Vocab v54

Collapse of the Atlantic northwest cod fishery

-communities fished cod for hundreds of years -new technology caught all the fish; population crashed -Canada declared moratorium in 1992 -loss of fishery cost $2 billion In the summer of 1992, when the Northern Cod biomass fell to 1% of earlier levels,[3] the Canadian Federal Minister of Fisheries and Oceans, John Crosbie, declared a moratorium on the Northern Cod fishery, which for the preceding 500 years had largely shaped the lives and communities of Canada's eastern coast.[4] A major factor that contributed to the depletion of the cod stocks off the shores of Newfoundland was the introduction of equipment and technology that increased the volume of landed fish.[5] From the 1950s onwards, new technology allowed fishermen to trawl a larger area, fish deeper, and for a longer time. By the 1960s, powerful trawlers equipped with radar, electronic navigation systems, and sonar allowed crews to pursue fish with unparalleled success, and Canadian catches peaked in the late-1970s and early-1980s.[6] Cod stocks were depleted at a faster rate than could be replenished. In June 2018, days before this image of an advertisement for cod for sale as fast food in New Brunswick after the long moratorium on the commercial Atlantic northwest cod fishery was taken, the federal government reduced the cod quota, finding that the cod stocks had fallen again after just two years of fair catches. We must make sure we don't repeat the past. Trying to implement sustainable fisheries management one population at a time has been a slow and ineffective process. Canada is not alone in this experience. Around the world, the catalyst for fisheries recovery, and the social, cultural and economic benefits that come along with it, has been a legally binding requirement to rebuild stocks. We can't keep fishing Northern cod the way we are today without risking its recovery in the long term. We must let it recover and become a rebuilding story that everyone can benefit from in the future.

A collapsing cloud of gas does not form a single star. Because of instabilities, the cloud breaks into fragments, producing perhaps thousands of stars. A stable group of stars that formed and are held together by their combined gravity is called a star cluster. In contrast, a stellar association is a group of stars that formed together but are not gravitationally bound to one another.

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Anger usually comes from selfishness. When you're mad at someone else it's because they were selfish. When someone is mad at you it's because you were selfish.

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As the global demand for cheap meat grows, the expansion of agricultural land is putting more and pressure on our forests, rivers and oceans, contributing to deforestation, soil erosion, marine pollution zones and the global biodiversity crisis, he said. "The UN has warned that if we continue as we are, the world's soils will have effectively gone within 60 years. And then what? We shouldn't look to the sea to bail us out because commercial fisheries are expected to be finished by 2048 ... "The rainforest homes of the likes of jaguars and the critically endangered sumatran elephants are being razed to make way for intensive crop production and plantations that are feeding factory farm animals ... the mixed farm habitats of once common farmland birds such as barn owls, turtle doves and skylarks are being stripped away, and ... vast quantities of wild fish are being scooped up to feed industrially reared farmed fish and chickens and pigs, leaving the likes of penguins, puffins and other species starving." Antibiotic use is another red flag area. "There is now overwhelming evidence that the routine prophylactic use of antibiotics is leading to the rise of antibiotic resistant superbugs, and the World Health Organisation has issued warnings that if we don't do something to curb antibiotic use in both human and animal medicine we will face a post-antibiotic era where currently treatable diseases will once again kill." Although some countries, the UK and the US for example, are now trying to cut back, antibiotic use is totally unregulated in other parts of the world: in China the farmers can just prescribe and administer antibiotics for themselves.

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Banning factory farms would mean the only meat available is local grass-fed blah blah. The price would shoot up drastically and people will be essentially forced to cut back because of less supply and because they simply can't afford it. As a vegan, I'm okay with this plan but you can see that the end result is the same as asking people to go vegan in the first place. Also good luck getting our heavily lobbied congress to ban factory farms.

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Breaking into your house is illegal. You probably don't abuse animals in your home or commit any level of substantial crime but your lack of having any legal activity you may want to hide does not imply I should break into your house to prove your innocence. This is very much one of those if you have nothing to hide then you shouldn't be closed off type things expect that entire idea is bullshit. Would you allow random people to just haphazardly go through your house doing what they please? Beyond that, it's not like these places just willingly allow random people to walk through as they please. Virtually all food production facilities are locked down hard with health and safety refs and most facilities whether food production or not just blatantly do not allow anyone on site without specifically signing into the visitors book and having any relevant inductions. I'm not even talking food industries at this point, it is completely 100% normal that regular people cannot just walk into whatever facilities they please. It is entirely unremarkable that it's illegal to break into, film and destroy property on farming operations as that is the status quo of literally every industry.

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Contracting stars heat up by converting gravitational energy into thermal energy. Low-mass stars have little gravitational energy, so when they contract, they can't get very hot. This limits the nuclear fuels they can ignite. In Chapter 10 Section 10-3b, you saw that objects less massive than 0.08 solar mass cannot sustain hydrogen fusion. Consequently, this section will concentrate on stars more massive than 0.08 solar mass but no more than about four times the mass of the Sun. Structural differences divide the lower-mainsequence stars into two subgroups, very-low-mass red dwarfs and medium-mass stars such as the Sun. The critical difference between the two groups is the extent of interior convection.

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General consumers continually demand lower prices. It's like people constantly drumming "Buy American!" yet always complain about the prices of American products. Lower prices require massive volume to be moved through the food chain at a low cost. This is what consumers get, because that's what they demand. They just don't perceive the process to get there.

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I don't put much stock in 'undercover expose' videos, because most of them seem focused on finding the worst and portraying them as typical.

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If stars didn't die, you wouldn't exist.

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In order for our ego to survive it needs enemies. The only way we can feel special is if others are not, and if those others are not there, all we have left is ourself. And the only reason we attack others is so we can feel good about ourselves. By attacking others you don't have to face the truth about yourself.

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Inspiration is everywhere, you just aren't paying attention.

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Meiosis I can take a long time. In human females, for example, meiosis I begins in the egg around birth but doesn't stop until puberty, meaning it may not complete this stage for decades. In fact, if the egg produced doesn't get fertilized, it never finishes meiosis II either. Here's an old-fashioned pregnancy test: inject a woman's urine into an African clawed frog, Xenopus laevis. If the woman is pregnant, the hormones in her urine will cause the frog to jump-start meiosis and produce eggs within 24 hours. Nowadays, we add those same hormones to monoclonal antibodies in urine dipsticks. Not only is this test much more accurate, it also means no more injections for the poor frogs.

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Most multiple star systems are triple stars. Systems with four or more components are less likely to occur.[5] Multiple-star systems are called triple, trinary or ternary if they contain three stars; quadruple or quaternary if they contain four stars; quintuple or quintenary with five stars; sextuple or sextenary with six stars; septuple or septenary with seven stars. These systems are smaller than open star clusters, which have more complex dynamics and typically have from 100 to 1,000 stars.[7] Most multiple star systems known are triple; for higher multiplicities, the number of known systems with a given multiplicity decreases exponentially with multiplicity.

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Natural laws have no pity.

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Of all the stars in the Orion Nebula, just one is hot enough to ionize the gas. Only photons with wavelengths shorter than 91.2 nm can ionize hydrogen. The second-hottest stars in the nebula are B1 stars, and they emit little of this ionizing radiation. The hottest star, however, is an O6 star that has 30 times the mass of the Sun. At a temperature of 40,000 K, it emits plenty of photons with wavelengths short enough to ionize hydrogen. Remove that one star, and the nebula's emission would turn off. As many as 85 percent of the stars in the Orion Nebula are surrounded by disks of gas and dust. One such disk is seen at the upper right of this Hubble Space Telescope image, magnified in the inset. Radiation from the nearby hot, luminous Trapezium stars is evaporating gas from the disk and driving it away to form an elongated nebula.

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Sharks are one of the ocean's most threatened species because they are mistakenly caught by vessels searching for fish, and end up getting tossed back into the ocean dead or dying[22] This disappearance of sharks has enabled prey animals like rays to multiply, which alters the food chain. Bycatch is the industry term for what they consider "unwanted or economically-worthless aquatic animals who are unintentionally caught using destructively indiscriminate fishing methods like longlines and driftnets, which generally target marketable marine creatures such as tuna and swordfish"[22] There are also billions of other animals that are killed in this manner every year such as: sea turtles, marine mammals, and sea birds. Between 1990 and 2008, it was estimated that 8.5 million sea turtles were fatally caught in nets or on longlines as bycatch. Fish farming is the raising of fish for food in underwater enclosures, otherwise known as aquaculture. There are environmental hazards such as waste, damage to ecosystems, and negative effects on humans. Because they are so densely packed together, the fecal matter that accumulates can create algal blooms, or deadly parasites and viruses that thrive on the filthy environment. These can infect wild fish that swim near the enclosure, or whole colonies of fish if an infected farm fish escapes the enclosure. Overfishing occurs because fish are captured at a faster rate than they can reproduce. Both advanced fishing technologies and increased demand for fish have resulted in overfishing. The Food and Agricultural Organization has reported that "about 25 percent of the world's captured fish end up thrown overboard because they are caught unintentionally, are illegal market species, or are of inferior quality and size" [23] It should not go unnoticed that overfishing has caused more ecological extinction than any other human influence on coastal ecosystems.

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The Sun generates its energy by breaking and reconnecting the bonds between the particles inside atomic nuclei. There are only four known forces in nature: the force of gravity, the electromagnetic force, and the strong and weak nuclear forces. The weak nuclear force is involved in the radioactive decay of certain kinds of nuclear particles, and the strong force binds together atomic nuclei. Thus, nuclear energy originates in the strong nuclear force.

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The only thing keeping you from your goals is consistently.

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The protostar stage is predicted to be less than 0.1 percent of a star's total lifetime, so, although that is a long time in human terms, you cannot expect to find many stars in the protostar stage. Furthermore, protostars form deep inside clouds of dusty gas that absorb any light the protostar might emit. Only when the protostar is hot enough to drive away its enveloping cloud of gas and dust does it become easy to observe at wavelengths your eye can see.

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Though mass alone does not reveal any pattern among giants, supergiants, and white dwarfs, density does. Once you know a star's mass and diameter, you can calculate its average density by dividing its mass by its volume. Stars are not uniform in density but are most dense at their centers and least dense near their surfaces. The center of the Sun, for instance, is about 100 times as dense as water; its density at the bottom of the photosphere is about 3400 times less dense than Earth's atmosphere at sea level. A star's average density is intermediate between its central and surface densities. The Sun's average density is approximately 1 gram per cubic centimeter—about the density of water. Main-sequence stars have average densities similar to the Sun's density. As you learned earlier in the discussion about luminosity classification, giant stars are much larger in diameter than the main-sequence stars but not much larger in mass, so giants have low average densities, ranging from 0.1 to 0.01 g/cm^3 . The enormous supergiants have still lower densities, ranging from 0.001 to 0.000001 g/cm^3 . These densities are thinner than the air you breathe, and if you could insulate yourself from the heat, you could fly an airplane through these stars. Only near the center would you be in any danger; astronomers calculate that the material there is very dense. The white dwarfs have masses about equal to the Sun's but are very small—only about the size of Earth. Thus, the matter is compressed to densities of 3 million g/cm3 or more. On Earth, a teaspoonful of this material would weigh about 15 tons

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To understand the mass-luminosity relation, you can consider both the law of hydrostatic equilibrium, which says that pressure balances weight, and the pressure- temperature thermostat, which regulates energy production. A star that is more massive than the Sun has more weight pressing down on its interior, so the interior must have a high pressure to balance that weight. That means the massive star's automatic pressure-temperature thermostat must keep the gas in its interior hot and the pressure high. A star less massive than the Sun has less weight on its interior and thus needs less internal pressure; therefore, its pressure-temperature thermostat is set lower. In other words, massive stars are more luminous because they must make more energy to support their larger weight. If they were not so luminous, they would not be stable.

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You might be wondering how the unimaginably cold gas of an interstellar cloud can heat up to form a star. The answer is gravity. Once part of a cloud is triggered to collapse, gravity draws each atom toward the center. At first the atoms fall unopposed; they hardly ever collide with each other. In this free-fall contraction, the atoms pick up speed as they fall until, by the time the gas becomes dense enough for the atoms to collide often, they are traveling very fast. Collisions convert the inward velocities of the atoms into random motions, and you remember that temperature is a measure of the random velocities of the atoms in a gas. Thus, the temperature of the gas goes up. As the internal temperature climbs, the gas becomes ionized, changing into a mixture of positively charged atomic nuclei and free electrons. The initial collapse of the gas forms a dense core of gas, and as more gas falls in, a warm protostar develops, buried deep in the dusty gas cloud that continues to contract, although much more slowly than free-fall. A protostar is an object that will eventually become a star. Theory predicts that protostars are luminous red objects larger than main-sequence stars, with temperatures ranging from a few hundred to a few thousand degrees Kelvin. Throughout its contraction, the protostar converts its gravitational energy into thermal energy. Half of this thermal energy radiates into space, but the remaining half raises the internal temperature. When the center gets hot enough, nuclear reactions begin generating enough energy to replace the radiation, leaving the surface of the star. The protostar then halts its contraction and becomes a stable, main-sequence star. The time a protostar takes to contract from a cool interstellar gas cloud to a main-sequence star depends on its mass. The more massive the star, the stronger its gravity and the faster it contracts. The Sun took about 30 million years to reach the main sequence, but a 15-solar-mass star can contract in only 100,000 years. Conversely, a star of 0.2 solar mass takes 1 billion years to reach the main sequence.

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interstellar reddening

1. First, very hot stars can excite clouds of gas and dust to emit light, and this reveals that the clouds contain mostly hydrogen gas at very low densities. 2. Second, where dusty clouds reflect the light of stars you see evidence that the dust in the clouds is made up of very small particles. 3. The third thing to notice is that some dense clouds of gas and dust are dark and are detectable only where they are silhouetted against background regions filled with stars or bright nebulae. If a cloud is less dense, the starlight may be able to penetrate it, and stars can be seen through the cloud; but the stars look dimmer because the dust in the cloud scatters some of the light. Because shorter wavelengths are scattered more easily than longer wavelengths, the redder photons are more likely to make it through the cloud, and the stars appear redder than they should for their respective spectral types. This effect is called interstellar reddening. The same physical process makes the setting Sun look red. Although you have been imagining individual nebulae, the thin gas and dust of the interstellar medium also fills the spaces between the nebulae. You can see evidence of that because the gas forms interstellar absorption lines in the spectra of distant stars, as shown in Figure 10-11. As starlight travels through the interstellar medium, gas atoms of elements such as calcium and sodium absorb photons of certain wavelengths, producing absorption lines. You can be sure those lines originate in the interstellar medium because they appear in the spectra of O and B stars—stars too hot to have visible calcium and sodium absorption lines in their own atmospheres. Also, the narrowness of the interstellar lines indicates they could not have been formed in the hot atmospheres of stars—the line widths indicate a very small range of Doppler shifts, meaning the atoms are moving at speeds corresponding to temperatures of only 10 to 50 K.

Does Precession of the Earth Affect Climate?

25,772 years, more or less. Axial precession is one of three periodic variations in the Earth's movements, along with axial tilt and orbital eccentricity, which combine to produce Milankovitch cycles. These cycles are named after Serbian geophysicist and astronomer Milutin Milanković, who in the 1920s theorized that combined effects of precession, variations in axial tilt, and variation of the eccentricity of the Earth's orbit strongly influenced its climatic patterns. As recently as 1982, the National Research Council of the U.S. National Academy of Sciences had embraced the Milankovitch Cycle model: ...orbital variations remain the most thoroughly examined mechanism of climatic change on time scales of tens of thousands of years and are by far the clearest case of a direct effect of changing insolation on the lower atmosphere of Earth (National Research Council, 1982).

how long did the egyptian empire last?

3,000 years The dynastic period started with the reign of Egypt's first king, Narmer, in approximately 3100 BCE, and ended with the death of Cleopatra VII in 30 BCE. During this long period there were times of strong centalised rule, and periods of much weaker, divided rule, but basically Egypt remained one, independent land.

how many miles is a light year?

6 trillion miles 5.879e+12 The average neutrino could pass unhindered through a lead wall more than 1 ly thick.

betelgeuse diameter miles

766.9 million mi

DNA-binding domain

A DNA-binding domain (DBD) is an independently folded protein domain that contains at least one structural motif that recognizes double- or single-stranded DNA. A DBD can recognize a specific DNA sequence (a recognition sequence) or have a general affinity to DNA.[1] Some DNA-binding domains may also include nucleic acids in their folded structure. One or more DNA-binding domains are often part of a larger protein consisting of further protein domains with differing function. The extra domains often regulate the activity of the DNA-binding domain. The function of DNA binding is either structural or involves transcription regulation, with the two roles sometimes overlapping. DNA-binding domains with functions involving DNA structure have biological roles in DNA replication, repair, storage, and modification, such as methylation.

eclipsing binary

A binary star system in which one star periodically blocks the light from the other. Can be detected by looking at the light curve (brightness/time)

visible binary

A binary star system in which the two stars are separately visible in the telescope.

bipolar outflow

A bipolar outflow comprises two continuous flows of gas from the poles of a star. Bipolar outflows may be associated with protostars (young, forming stars), or with evolved post-AGB stars (often in the form of bipolar nebulae). The presence of a bipolar outflow shows that the central star is still accumulating material from the surrounding cloud via an accretion disk. The outflow relieves the build-up of angular momentum as material spirals down onto the central star through the accretion disk. The magnetised material in these protoplanetary jets is rotating and comes from a wide area in the protostellar disk.[1]

Thousands of Atlantic salmon escape into Pacific Northwest waters

A catastrophic failure of a large aquaculture pen near Cypress Island recently freed thousands of nonnative Atlantic salmon into Puget Sound, near Seattle. In the aftermath of this outbreak, the Wild Fish Conservancy has launched a lawsuit against Cooke Aquaculture, the international corporation responsible for the accident. Puget Sound, the large Pacific estuary system in Washington state, offers the perfect refuge for spawning coho, Chinook and sockeye salmon, but in late August, local fishermen were bewildered when they caught Atlantic salmon, as well. Days later, the news broke that 160,000 or more Atlantic salmon had escaped from damaged aquaculture nets moored off the San Juan Islands.

How many species are critically endangered?

A critically endangered (CR) species is one that has been categorized by the International Union for Conservation of Nature (IUCN) as facing an extremely high risk of extinction in the wild. As of 2014, there are 2,464 animal and 2,104 plant species with this assessment.

Conchoidal fracture

A curved fracture surface; looks like the inside of a clam shell Conchoidal fracture is a smoothly curving fracture surface of fine-grained materials which have no planar surfaces of internal weakness or planes of separation (no cleavage). Such a curving fracture surface is characteristic of glass and other brittle materials with no crystal structure.

How do I make a Faraday cage?

A faraday cage is any conductive surface that encloses what's inside of it. The Faraday cage is just a manifestation of the fact that below a certain orifice size (hole) in a piece of metal, a given frequency of electromagnetic wave will see it is as a solid piece of metal. So it will (mostly) bounce (reflect) off. The size of the hole needs to be 1/10 of the wavelength of the EM wave, or smaller. This is how you can see your food in a microwave, but not get your brain cooked when watching you popcorn pop. If you look close in the door, you will see tiny holes. Holes are preferable to crossed wires, as they are the same distance across in all orientations. If you use a wire mesh, you need to size it for the diagonal distance to protect from all orientations of radiation. A Faraday cage operates because an external electrical field causes the electric charges within the cage's conducting material to be distributed so that they cancel the field's effect in the cage's interior. This phenomenon is used to protect sensitive electronic equipment (for example RF receivers) from external radio frequency interference (RFI) often during testing or alignment of the device. Faraday cages are also used to enclose devices that produce RFI, such as radio transmitters, to prevent their radio waves from interfering with nearby sensitive equipment. They are also used to protect people and equipment against actual electric currents such as lightning strikes and electrostatic discharges, since the enclosing cage conducts current around the outside of the enclosed space and none passes through the interior.

Feedlot

A feedlot or feed yard is a type of animal feeding operation which is used in intensive animal farming, notably beef cattle, but also swine, horses, sheep, turkeys, chickens or ducks, prior to slaughter.

Deep foundation

A foundation that transfers building loads into the earth well below the building structure. A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site. There are many reasons that a geotechnical engineer would recommend a deep foundation over a shallow foundation, such as for a skyscraper. Some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints like property lines. There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally driven into the ground in situ; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete or prestressed concrete.

vertical management

A hierarchical organization structure in which management or supervisors pass information and orders from the top of the organizational pyramid down toward the bottom. Little communication or feedback flows from the bottom up or from side to side.

Seet call

A high-pitched call made by birds to warn of the presence or approach of a predator.

anadromous

A life cycle in which creatures are hatched in fresh water, migrate to salt water as adults, and then go back to fresh water in order to reproduce (of a fish such as the salmon) migrating up rivers from the sea to spawn. Anadromous fishes, including many salmonids, lampreys, shad, and sturgeon, spend most of their lives in the sea and migrate to freshwater to reproduce. American and European eels are catadromous fishes, which spend most of their lives in freshwater and migrate to the sea to reproduce.

Giant stars

A main-sequence star generates its energy by nuclear fusion reactions that combine hydrogen to make helium. A star remains on the main sequence for a time span equal to 90 percent of its total existence as an energy-generating star. When the hydrogen is exhausted, however, the star begins to evolve rapidly. It swells into a giant star and then begins to fuse helium into heavier elements. A star can remain in this giant stage for only about 10 percent of its total lifetime; then, it must die. The giant-star stage is the first step in the death of a star. So all stars start as main sequence stars? The nuclear reactions in a main-sequence star's core produce helium. Helium can fuse into heavier elements only at temperatures higher than 100,000,000 K, and no mainsequence star has a core that hot, so helium accumulates at the star's center like ashes in a fireplace. Initially, this helium ash has little effect on the star, but as hydrogen is exhausted and the stellar core becomes almost pure helium, the star's ability to generate nuclear energy is reduced. Because the energy generated at the center is what opposes gravity and supports the star, the core begins to contract as soon as the energy generation starts to decline. Although the core of helium ash cannot generate nuclear energy, it can grow hotter because it contracts and converts gravitational energy into thermal energy. The rising temperature heats the unprocessed hydrogen just outside the core—hydrogen that previously was not hot enough to fuse. When the temperature of the surrounding hydrogen becomes high enough, hydrogen fusion begins in a spherical layer, called a shell, surrounding the exhausted core of the star. Like a grass fire burning outward from an exhausted campfire, the hydrogen-fusion shell creeps outward, leaving helium ash behind and increasing the mass of the helium core. Figure 11-1 illustrates how the flood of energy produced by the hydrogen-fusion shell pushes toward the surface, heating the outer layers of the star and forcing them to expand dramatically. Stars like the Sun become giant stars 10 to 100 times the current diameter of the Sun, and the most massive stars become supergiant stars as much as 1000 times larger than the Sun. The expansion of a star to giant or supergiant size cools the star's outer layers, and so the stars move toward the upper right in the H-R diagram. Look back to Figure 9-8 and notice that some of the most familiar stars, such as Aldebaran, Betelgeuse, and Polaris, are giants or supergiants. Although the energy output of the hydrogen-fusion shell can force the envelope of the star to expand, it cannot stop the contraction of the helium core. Because the core is not hot enough to fuse helium, gravity squeezes it to a relatively tiny size. If you represented a typical giant star as being the size of a baseball stadium, its helium core would be only about the size of a baseball, yet would contain about 10 percent of the star's mass.

DNA microarray

A microarray of immobilized single-stranded DNA fragments of known nucleotide sequence that is used especially in the identification and sequencing of DNA samples and in the analysis of gene expression (as in a cell or tissue). research tool used to study gene expression The core principle behind microarrays is hybridization between two DNA strands, the property of complementary nucleic acid sequences to specifically pair with each other by forming hydrogen bonds between complementary nucleotide base pairs. A high number of complementary base pairs in a nucleotide sequence means tighter non-covalent bonding between the two strands. After washing off non-specific bonding sequences, only strongly paired strands will remain hybridized. Fluorescently labeled target sequences that bind to a probe sequence generate a signal that depends on the hybridization conditions (such as temperature), and washing after hybridization. Total strength of the signal, from a spot (feature), depends upon the amount of target sample binding to the probes present on that spot. Microarrays use relative quantitation in which the intensity of a feature is compared to the intensity of the same feature under a different condition, and the identity of the feature is known by its position.

Pile driver

A pile driver is a device used to drive piles into soil to provide foundation support for buildings or other structures. The term is also used in reference to members of the construction crew that work with pile-driving rigs.

Electrophilic aromatic substitution

A reaction in which an electrophile is substituted for a hydrogen on an aromatic ring. Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system is replaced by an electrophile.

Reflection Nebula

A reflection nebula is produced when starlight scatters from the dust in a nebula. Consequently, the spectrum of a reflection nebula is just the reflected spectrum of the starlight, atmospheric absorption lines included. Gas is surely present in a reflection nebula, but it is not excited enough to emit photons. Image: The hottest stars in the Pleiades star cluster are spectral type B6, not hot enough to ionize hydrogen in the ISM. Instead, the brightest stars produce a reflection nebula as their light is scattered from interstellar dust in a cloud that the cluster happens to be passing through.

Semelparity and iteroparity

A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characterized by multiple reproductive cycles over the course of its lifetime.

Spectroscopic binary system

A star system in which the stars are too close together to be visible separately. We see a single point of light, and only by taking a spectrum can we determine that there are two stars. Familiar examples of spectroscopic binary systems are the stars Mizar and Alcor in the handle of the Big Dipper

spectral class

A star's label in the temperature classification system based on the appearance of the star's spectrum O, B, A, F, G, K, and M. This set of star types, called the spectral sequence, is important because it is a temperature sequence. The O stars are the hottest, and the temperature continues to decrease down to the M stars, the coolest. For further precision, astronomers divide each spectral class into 10 subclasses. For example, spectral class A consists of the subclasses A0, A1, A2, . . . A8, A9. Next come F0, F1, F2, and so on. These finer divisions define a star's temperature to a precision of about 5 percent. The Sun, for example, is not just a G star, but a G2 star, with a temperature of 5800 K. Generations of astronomy students have remembered the spectral sequence by using mnemonics such as "Oh Boy, An F Grade Kills Me," or "Only Bad Astronomers Forget Generally Known Mnemonics." The study of spectral types is more than a century old, but astronomers continue to discover and define new types. The L dwarfs, found in 1998, are cooler and fainter than M stars. They are understood to be objects smaller than stars but larger than planets and are called brown dwarfs, which you will learn more about in a later chapter. The spectra of M stars contain bands produced by metal oxides, such as titanium oxide (TiO), but L dwarf spectra contain bands produced by molecules such as iron hydride (FeH). The T dwarfs are an even cooler and fainter type of brown dwarfs than L dwarfs. Their spectra show absorption by methane (CH4 ) and water vapor. In 2011, astronomers using highly sensitive infrared detectors on space telescopes and large ground-based telescopes discovered a class of objects with temperatures below 500 K that are labeled Y dwarfs.

congress recess

A temporary interruption of the Senate's proceedings, sometimes within the same day. The Senate may also recess overnight rather than adjourn at the end of the day. Recess also refers to longer breaks, such as the breaks taken during holiday periods, pursuant to concurrent resolution. act. The provision was intended to prevent one house from thwarting legislative business simply by refusing to meet. To avoid obtaining consent during long recesses, the House or Senate may sometimes hold pro forma meetings, sometimes only minutes long, every three days.

Tuna

A tuna (also called tunny) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera,[2] the sizes of which vary greatly, ranging from the bullet tuna (max. length: 50 cm (1.6 ft), weight: 1.8 kg (4 lb)) up to the Atlantic bluefin tuna (max. length: 4.6 m (15 ft), weight: 684 kg (1,508 lb)). The bluefin averages 2 m (6.6 ft), and is believed to live up to 50 years. Tuna, opah, and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. Can swim 47 mph. Tunas achieve endothermy by conserving the heat generated through normal metabolism. In all tunas, the heart operates at ambient temperature, as it receives cooled blood, and coronary circulation is directly from the gills.[43] The rete mirabile ("wonderful net"), the intertwining of veins and arteries in the body's periphery, allows nearly all of the metabolic heat from venous blood to be "re-claimed" and transferred to the arterial blood via a counter-current exchange system, thus mitigating the effects of surface cooling.[44] This allows the tuna to elevate the temperatures of the highly-aerobic tissues of the skeletal muscles, eyes and brain,[41][43] which supports faster swimming speeds and reduced energy expenditure, and which enables them to survive in cooler waters over a wider range of ocean environments than those of other fish.[42] Also unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red myotomal muscles derive their color from myoglobin, an oxygen-binding molecule, which tuna express in quantities far higher than most other fish. The oxygen-rich blood further enables energy delivery to their muscles.[41] For powerful swimming animals like dolphins and tuna, cavitation may be detrimental, because it limits their maximum swimming speed.[45] Even if they have the power to swim faster, dolphins may have to restrict their speed, because collapsing cavitation bubbles on their tail are too painful. Cavitation also slows tuna, but for a different reason. Unlike dolphins, these fish do not feel the bubbles, because they have bony fins without nerve endings. Nevertheless, they cannot swim faster because the cavitation bubbles create a vapor film around their fins that limits their speed. Lesions have been found on tuna that are consistent with cavitation damage.[45] The Australian government alleged in 2006 that Japan had illegally overfished southern bluefin by taking 12,000 to 20,000 tonnes per year instead of the agreed upon 6,000 tonnes; the value of such overfishing would be as much as US$2 billion.[46]

parsec

A unit of distance that is equal to 3.26 light years

Ventifact

A ventifact is a rock that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals. Common on Antarctica

Wet market

A wet market is a marketplace selling fresh meat, fish, produce, and other perishable goods as distinguished from "dry markets" that sell durable goods such as fabric and electronics.

absolute visual magnitude (Mᵥ)

Absolute visual magnitude (Mᵥ) , which is the apparent visual magnitude that star would have if it were 10 pc away. The subscript V tells you it is a visual magnitude, referring only to the wavelengths of light your eye can see. Other magnitude systems are based on other parts of the electromagnetic spectrum, such as infrared and ultraviolet radiation. The Sun's absolute magnitude is easy to calculate because its distance and apparent magnitude are well known. The absolute visual magnitude of the Sun is about +4.8. In other words, if the Sun were only 10 pc (33 ly) from Earth, not a great distance in astronomy, it would have an apparent magnitude of +4.8 and look no brighter to your eye than the faintest star in the handle of the Little Dipper

broodstock

Adult fish retained for spawning Broodstock, or broodfish, are a group of mature individuals used in aquaculture for breeding purposes. Broodstock can be a population of animals maintained in captivity as a source of replacement for, or enhancement of, seed and fry numbers.

Agrobacterium

Agrobacterium is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. Agrobacterium tumefaciens is the most commonly studied species in this genus. Agrobacterium is well known for its ability to transfer DNA between itself and plants, and for this reason it has become an important tool for genetic engineering. Agrobacterium tumefaciens causes crown-gall disease in plants. The disease is characterised by a tumour-like growth or gall on the infected plant, often at the junction between the root and the shoot. Tumors are incited by the conjugative transfer of a DNA segment (T-DNA) from the bacterial tumour-inducing (Ti) plasmid. The ability of Agrobacterium to transfer genes to plants and fungi is used in biotechnology, in particular, genetic engineering for plant improvement. A modified Ti or Ri plasmid can be used. The plasmid is 'disarmed' by deletion of the tumor inducing genes; the only essential parts of the T-DNA are its two small (25 base pair) border repeats, at least one of which is needed for plant transformation.[13][14] The genes to be introduced into the plant are cloned into a plant transformation vector that contains the T-DNA region of the disarmed plasmid, together with a selectable marker (such as antibiotic resistance) to enable selection for plants that have been successfully transformed.

Algal bloom

Algal blooms are the result of a nutrient, like nitrogen or phosphorus from fertilizer runoff (or high concentrations of feces from fish farming), entering the aquatic system and causing excessive growth of algae. An algal bloom affects the whole ecosystem. Consequences range from the benign feeding of higher trophic levels, to more harmful effects like blocking sunlight from reaching other organisms, causing a depletion of oxygen levels in the water, and, depending on the organism, secreting toxins into the water. The process of the oversupply of nutrients leading to algae growth and oxygen depletion is called eutrophication. Blooms that can injure animals or the ecology are called "harmful algal blooms" (HAB), and can lead to fish die-offs, cities cutting off water to residents, or states having to close fisheries.

CNO (carbon-nitrogen-oxygen) cycle

All main-sequence stars fuse hydrogen into helium to generate energy. The Sun and smaller stars fuse hydrogen by the proton-proton chain. Upper-main-sequence stars, more massive than the Sun, fuse hydrogen by a more efficient process called the CNO (carbon-nitrogen-oxygen) cycle. The CNO cycle begins with a carbon nucleus and transforms it first into a nitrogen nucleus, then into an oxygen nucleus, and then back to a carbon nucleus. The carbon is unchanged in the end, but along the way four hydrogen nuclei are fused to make a helium nucleus plus energy, just as in the proton-proton chain. A carbon nucleus has six times more positive electric charge than hydrogen, so the Coulomb barrier is higher than for combining two protons. Temperatures higher than 16,000,000 K are required to make the CNO cycle work: The center of the Sun is not quite hot enough for this reaction. In stars more massive than about 1.1 solar masses, the cores are hot enough and the CNO cycle dominates over the slower proton-proton chain. In both the proton-proton chain and the CNO cycle, energy appears in the form of gamma-rays, positrons, and neutrinos. The gamma-rays are photons that are absorbed by the surrounding gas before they can travel more than a few centimeters. This heats the gas. The positrons produced in the first reaction combine with free electrons, and both particles vanish, converting their mass into more gamma-rays. Thus, the positrons also help keep the center of the star hot. The neutrinos, however, are particles that travel at nearly the speed of light and almost never interact with other particles. The average neutrino could pass unhindered through a lead wall more than 1 ly thick. Consequently, the neutrinos do not help heat the gas but race out of the star, carrying away roughly 2 percent of the energy produced.

Pacific bluefin tuna

Almost all fish are cold-blooded (ectothermic).[13] However, tuna and mackerel sharks are warm-blooded: they can regulate their body temperature. Warm-blooded fish possess organs near their muscles called retia mirabilia that consist of a series of minute parallel veins and arteries that supply and drain the muscles. As the warmer blood in the veins returns to the gills for fresh oxygen it comes into close contact with cold, newly oxygenated blood in the arteries. The system acts as a counter-current heat exchanger and the heat from the blood in the veins is given up to the colder arterial blood rather than being lost at the gills. The net effect is less heat loss through the gills. Fish from warmer water elevate their temperature a few degrees whereas those from cold water may raise it as much as 20 °C (36 °F) warmer than the surrounding sea. According to stock assessments completed in 2011, 2014 and 2016 by the International Scientific Committee for Tuna and Tuna-Like Species in the North Pacific Ocean (ISC), the present-day population is at just 2.6 percent of its historic levels.[26] The overall fishing mortality rate for this species remains up to three times higher than is sustainable.[27] In 2010, it was estimated that the complete spawning biomass was 40-60% of the historically observed spawning biomass.[1] In 2000-2004, between 16,000 tonnes and 29,000 tonnes were caught per year.[1] As much as 90% of the caught Pacific bluefins are juveniles.[28]

Endonuclease

An enzyme that cleaves its nucleic acid substrate at internal sites in the nucleotide sequence. Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically, while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences. cas9 is an example

Thwaites Glacier

Antarctica's Thwaites Glacier has been in the spotlight in recent years, as scientists have undertaken a multi-part international project to study the vast glacier from all angles. The urgency stems from observations and analyses showing that the amount of ice flowing from Thwaites—and contributing to sea level rise—has doubled in the span of three decades. Scientists think the glacier could undergo even more dramatic changes in the near future. Left 2001, Right 2019

induced pluripotent stem cells (iPS)

Any cell, even a highly differentiated cell in the adult body, that has been genetically reprogrammed to mimic the pluripotent behavior of embryonic stem cells Pluripotent stem cells hold promise in the field of regenerative medicine.[3] Because they can propagate indefinitely, as well as give rise to every other cell type in the body (such as neurons, heart, pancreatic, and liver cells), they represent a single source of cells that could be used to replace those lost to damage or disease. Induced pluripotent stem cells (also known as iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from a somatic cell. The iPSC technology was pioneered by Shinya Yamanaka's lab in Kyoto, Japan, who showed in 2006 that the introduction of four specific genes (named Myc, Oct3/4, Sox2 and Klf4) encoding transcription factors could convert somatic cells into pluripotent stem cells.[1] He was awarded the 2012 Nobel Prize along with Sir John Gurdon "for the discovery that mature cells can be reprogrammed to become pluripotent."[2] The most well-known type of pluripotent stem cell is the embryonic stem cell. However, since the generation of embryonic stem cells involves destruction (or at least manipulation)[4] of the pre-implantation stage embryo, there has been much controversy surrounding their use. Further, because embryonic stem cells can only be derived from embryos, it has so far not been feasible to create patient-matched embryonic stem cell lines.

Helium Fusion

As a star becomes a giant, fusing hydrogen in a shell, the inert core of helium ash contracts and grows hotter. When the core finally reaches a temperature of 100,000,000 K, helium nuclei can begin fusing to make carbon nuclei. The ignition of helium in the core changes the structure of the star. The star now makes energy in two locations by two different processes, helium fusion in the core and hydrogen fusion in the surrounding shell. The energy flowing outward from the core halts the contraction of the core, and at the same time the star's envelope contracts and grows hotter. Consequently, the point that represents the star in the H-R diagram moves downward, corresponding to lower luminosities, and to the left, corresponding to higher surface temperatures (Figure 11-2), to a region above the main sequence called the horizontal branch. Astronomers sometimes refer to stars with those characteristics as "yellow giants." Helium fusion produces carbon and oxygen that accumulate in an inert core. Once again, the core contracts and heats up, and a helium-fusion shell ignites below the hydrogen-fusion shell. The star now makes energy in two fusion shells, so it quickly expands and its surface cools once again. The point that represents the star in the H-R diagram moves back to the right, completing a loop to become a red giant again. The approximate rule is that if the core of a post-main-sequence star is "dead" (has no nuclear reactions), the star is a red giant, and if the core is "alive" (has fusion reactions), the star is a yellow giant.

How star clusters prove stellar evolution

Astronomers look at star clusters and say, "Aha! Evidence to solve a mystery." The stars in a star cluster all formed about the same time and from the same cloud of gas, so they must be about the same age and composition. Each star cluster freeze-frames and makes visible a moment in stellar evolution. The differences you see among stars in one cluster must arise from differences in their masses. You can estimate the age of a star cluster by observing the distribution of the points that represent its stars in the H-R diagram. A star cluster's H-R diagram shape is governed by the evolutionary paths the stars take. By comparing clusters of different ages, you can visualize how stars evolve almost as if you were watching a film of a star cluster changing over billions of years. Were it not for star clusters, astronomers would have little confidence in their understanding of the theories of stellar evolution. Star clusters make that evolution visible and assure astronomers that they really do know how stars are born, live, and die.

Supramolecular chemistry

Based on lock-and-key hypothesis: ability of one molecule to interact with another in a highly specific manner. Supramolecular chemistry is the domain of chemistry concerning chemical systems composed of a discrete number of molecules. The strength of the forces responsible for spatial organization of the system range from weak intermolecular forces, electrostatic charge, or hydrogen bonding to strong covalent bonding, provided that the electronic coupling strength remains small relative to the energy parameters of the component. Whereas traditional chemistry concentrates on the covalent bond, supramolecular chemistry examines the weaker and reversible non-covalent interactions between molecules.[3] These forces include hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, pi-pi interactions and electrostatic effects.[4] Important concepts advanced by supramolecular chemistry include molecular self-assembly, molecular folding, molecular recognition, host-guest chemistry, mechanically-interlocked molecular architectures, and dynamic covalent chemistry.[5] The study of non-covalent interactions is crucial to understanding many biological processes that rely on these forces for structure and function. Biological systems are often the inspiration for supramolecular research.

man on top of buffalo skull pile

Bison were hunted almost to extinction in the 19th century and were reduced to a few hundred by the mid-1880s. They were hunted for their skins, with the rest of the animal left behind to decay on the ground. Hides were prepared and shipped to the east and Europe (mainly Germany) for processing into leather. Homesteaders collected bones from carcasses left by hunters. Bison bones were used in refining sugar, and in making fertilizer and fine bone china. Bison bones price was from $2.50 to $15.00 a ton.

can different bird species communicate with each other?

But birds do communicate with one another. There are also cases where birds communicate across species lines. Alarm calls (seet calls) seems to be an area of interspecies communication where the message is communicated, understood and even repeated by perching birds of various species.

Carcosa

Carcosa is a fictional city in Ambrose Bierce's short story "An Inhabitant of Carcosa" (1886). The ancient and mysterious city is barely described and is viewed only in hindsight (after its destruction) by a character who once lived there.

Meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

Cloning

Cloning is the process of producing genetically identical individuals of an organism either naturally or artificially. In nature, many organisms produce clones through asexual reproduction. Cloning in biotechnology refers to the process of creating clones of organisms or copies of cells or DNA fragments (molecular cloning). Beyond biology, the term refers to the production of multiple copies of digital media or software. Cloning is a natural form of reproduction that has allowed life forms to spread for hundreds of millions of years. It is the reproduction method used by plants, fungi, and bacteria, and is also the way that clonal colonies reproduce themselves.[4][5] Examples of these organisms include blueberry plants, hazel trees, the Pando trees,[6][7] the Kentucky coffeetree, Myrica, and the American sweetgum. Cloning of any DNA fragment essentially involves four steps: - fragmentation - breaking apart a strand of DNA - ligation - gluing together pieces of DNA in a desired sequence - transfection - inserting the newly formed pieces of DNA into cells - screening/selection - selecting out the cells that were successfully transfected with the new DNA Cloning stem cells Somatic-cell nuclear transfer, popularly known as SCNT, can also be used to create embryos for research or therapeutic purposes. The most likely purpose for this is to produce embryos for use in stem cell research. This process is also called "research cloning" or "therapeutic cloning". The goal is not to create cloned human beings (called "reproductive cloning"), but rather to harvest stem cells that can be used to study human development and to potentially treat disease. While a clonal human blastocyst has been created, stem cell lines are yet to be isolated from a clonal source.[10] Therapeutic cloning is achieved by creating embryonic stem cells in the hopes of treating diseases such as diabetes and Alzheimer's. The process begins by removing the nucleus (containing the DNA) from an egg cell and inserting a nucleus from the adult cell to be cloned.[11] In the case of someone with Alzheimer's disease, the nucleus from a skin cell of that patient is placed into an empty egg. The reprogrammed cell begins to develop into an embryo because the egg reacts with the transferred nucleus. The embryo will become genetically identical to the patient.[11] The embryo will then form a blastocyst which has the potential to form/become any cell in the body.[12] The reason why SCNT is used for cloning is because somatic cells can be easily acquired and cultured in the lab. This process can either add or delete specific genomes of farm animals. A key point to remember is that cloning is achieved when the oocyte maintains its normal functions and instead of using sperm and egg genomes to replicate, the oocyte is inserted into the donor's somatic cell nucleus.[13] The oocyte will react on the somatic cell nucleus, the same way it would on sperm cells.[13]

conservation laws

Conservation laws say that certain things cannot be created out of nothing or vanish into nothing. Such conservation laws are powerful aids to help you understand how nature works. conservation of mass: It says that the total mass of a star must equal the sum of the masses of its shells. conservation of energy: It says that the amount of energy flowing out of the top of a layer in the star must be equal to the amount of energy coming in at the bottom, plus whatever energy is generated within the layer. That means that the energy leaving the surface of the star, its luminosity, must equal the sum of the energies generated in all the layers inside the star.

Process of genetic engineering

Creating a GMO is a multi-step process. Genetic engineers must first choose what gene they wish to insert into the organism. This is driven by what the aim is for the resultant organism and is built on earlier research. Genetic screens can be carried out to determine potential genes and further tests then used to identify the best candidates. The development of microarrays, transcriptomics and genome sequencing has made it much easier to find suitable genes.[50] Luck also plays its part; the round-up ready gene was discovered after scientists noticed a bacterium thriving in the presence of the herbicide.[51] The next step is to isolate the candidate gene. The cell containing the gene is opened and the DNA is purified.[52] The gene is separated by using restriction enzymes to cut the DNA into fragments[53] or polymerase chain reaction (PCR) to amplify up the gene segment.[54] These segments can then be extracted through gel electrophoresis. If the chosen gene or the donor organism's genome has been well studied it may already be accessible from a genetic library. If the DNA sequence is known, but no copies of the gene are available, it can also be artificially synthesised.[55] Once isolated the gene is ligated into a plasmid that is then inserted into a bacterium. The plasmid is replicated when the bacteria divide, ensuring unlimited copies of the gene are available.[56] Before the gene is inserted into the target organism it must be combined with other genetic elements. These include a promoter and terminator region, which initiate and end transcription. A selectable marker gene is added, which in most cases confers antibiotic resistance, so researchers can easily determine which cells have been successfully transformed. The gene can also be modified at this stage for better expression or effectiveness. These manipulations are carried out using recombinant DNA techniques, such as restriction digests, ligations and molecular cloning.[57] There are a number of techniques used to insert genetic material into the host genome. Some bacteria can naturally take up foreign DNA. This ability can be induced in other bacteria via stress (e.g. thermal or electric shock), which increases the cell membrane's permeability to DNA; up-taken DNA can either integrate with the genome or exist as extrachromosomal DNA. DNA is generally inserted into animal cells using microinjection, where it can be injected through the cell's nuclear envelope directly into the nucleus, or through the use of viral vectors.[58] In plants the DNA is often inserted using Agrobacterium-mediated recombination,[59] taking advantage of the Agrobacteriums T-DNA sequence that allows natural insertion of genetic material into plant cells.[60] Other methods include biolistics, where particles of gold or tungsten are coated with DNA and then shot into young plant cells,[61] and electroporation, which involves using an electric shock to make the cell membrane permeable to plasmid DNA As only a single cell is transformed with genetic material, the organism must be regenerated from that single cell. In plants this is accomplished through the use of tissue culture.[62][63] In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells.[64] Bacteria consist of a single cell and reproduce clonally so regeneration is not necessary. Selectable markers are used to easily differentiate transformed from untransformed cells. These markers are usually present in the transgenic organism, although a number of strategies have been developed that can remove the selectable marker from the mature transgenic plant.[65]

Cultured meat

Cultured meat is meat produced by in vitro cell culture of animal cells, instead of from slaughtered animals.[1] It is a form of cellular agriculture. There are three stages in the production of cultured meat: selection of starter cells, treatment of growth medium, and scaffolding. The initial stage of growing cultured meat is to collect cells that have a rapid rate of proliferation (high cell reproduction rate). Such cells include embryonic stem cells, adult stem cells, myosatellite cells, or myoblasts. Stem cells proliferate the quickest, but have not yet begun development towards a specific kind of cell, which creates the challenge of splitting the cells and directing them to grow a certain way. Fully developed muscle cells are ideal in the aspect that they have already finished development as a muscle, but proliferate hardly at all. Therefore, cells such as myosatellite and myoblast cells are often used as they still proliferate at an acceptable rate, but also sufficiently differentiate from other types of cells. The cells are then treated by applying a solution that promotes tissue growth, which is known as a growth medium. These mediums should contain the necessary nutrients and appropriate quantity of growth factors. They are then placed in a culture medium, in a bio-reactor, which is able to supply the cells with the energetic requirements they need. To culture three-dimensional meat, the cells are grown on a scaffold, which is a component that directs its structure and order. The ideal scaffold is edible so the meat does not have to be removed, and periodically moves to stretch the developing muscle, thereby simulating the animal body during normal development. Additionally the scaffold must maintain flexibility in order to not detach from the developing myotubes (early muscle fibers). Scaffold must also allow vascularization (creation of blood vessels) in order for normal development of muscle tissue. Heme Proteins In October 2019 MDPI published an article entitled Extracellular Heme Proteins Influence Bovine Myosatellite Cell Proliferation and the Color of Cell-Based Meat[75] that claimed that skeletal muscle-tissue engineering can be applied to produce cell-based meat for human consumption. Myoglobin was reported to have increased the proliferation and metabolic activity of bovine muscle satellite cells. The addition of either myoglobin or hemoglobin was reported to change of color of the product to more closly resemble traditional beef. Proliferating cells need a food source to grow and develop. The growth medium should be a well-balanced mixture of ingredients and growth factors. Scientists have already identified possible growth media for turkey,[83] fish,[84] sheep[85] and pig[86] muscle cells. _____________ Cyanobacteria hydrolysate is used as the source of nutrients and energy for muscle cell production. Cyanobacteria are assumed to be cultivated in an open pond made of concrete. The protein content of cyanobacteria species varies generally between 50 and 70% of DM,8 and in this study a protein content of 64% of DM was assumed. After harvesting, the cyanobacteria biomass is sterilized and hydrolyzed to break down the cells. The stem cells are taken from an animal embryo. Embryonic stem cells have almost infinite self-renewal capacity and theoretically one cell line would be sufficient to feed the world.4 However, slow accumulation of genetic mutations over time limits the maximum proliferation period. As an embryonic stem cell can produce more than 1000 kg cultured meat, the impacts related to the production of the stem cells are not included in this study. Engineered Escherichia coli bacteria are used for the production of specific growth factors that induce the stem cells to differentiate into muscle cells. Those growth factors are proteins or hormones specific for the species used. The muscle cells are grown in a bioreactor on a medium composed of the cyanobacterial hydrolysate supplemented with the growth factors and vitamins. It is assumed that cyanobacteria hydrosylate is used as an energy and nutrient source for the growth and proliferation of the muscle cells. Nitrogen-fixing cyanobacteria species, such as Anabaena sp. or Nostoc sp., 9 can be used, but the most common commercially produced cyanobacteria species, Arthrospira platensis and Arthrospira maxima (Spirulina), do not fix atmospheric nitrogen gas. In the base scenario, synthetic nitrogen fertilizers are used, but the impacts of using nitrogen-fixing species are assessed in the sensitivity analysis. Synthetic fertilizers can also be replaced by using nutrient-rich wastewater or organic fertilizers Cyanobacteria biomass is assumed to be cultivated in an open pond (0.30 m deep) and harvested by using sedimentation and continuous vacuum belt filters. The energy requirements used for cultivation of cyanobacteria, harvesting, fertilizer production, and construction and maintenance of the facility are based on the data from Chisti10 (Table 2). It is assumed that after harvesting the cyanobacteria biomass is transported without drying for 50 km, assuming energy need of 2.6 MJ t^-1 km^-1 . As large-scale cultured meat production does not currently exist, in this study the calculations are based on a hypothetical large-scale production system. The cyanobacteria biomass was assumed to be sterilized using autoclaving, and a cylinder stirred-tank bioreactor was assumed to be used for cultivation of the muscle cells. It is assumed that the bioreactor is made from stainless steel. Production of 1 kg stainless steel requires 30.6 MJ primary energy and emits 3.38 kg CO2-eq kg^-1. As cells produce heat during the growth, additional energy inputs in heating the reactor are not required. The bioreactor is assumed to be used for 20 years. During sterilization, 40% of the water embodied in the biomass is assumed to be lost. Water needed for muscle cell cultivation is 30 m3 , and the DM content of the end product (cultured meat) is 30%. It is assumed that 80% of the water used at the cell culturing process is recycled without any treatment. https://sci-hub.tw/https://pubs.acs.org/doi/full/10.1021/es200130u

how many different species have had their genome sequenced?

Currently, scientists have only sequenced the genomes of about 3,500 species of complex life and only about 100 have been sequenced at "reference quality" which is used for in-depth research. We need to do better than this. A species seed vault must be made before more species go extinct.

Binary star orbits

Each star in a binary system moves in its own orbit around the system's center of mass, the balance point of the system (look back to Chapter 3, Concept Art 3B). If one star is more massive than its companion, then the massive star is closer to the center of mass and travels in a smaller orbit, while the lower-mass star whips around in a larger orbit (Figure 9-11). The ratio of the masses of the stars in the binary system portrayed in Figure 9-11 is Ma/Mb , which equals Rb/Ra , the inverse of the ratio of the radii of the orbits. For example, if one star in a binary system has an orbit twice as large as the other star's orbit, then it must be half as massive. Getting the ratio of the masses is easy, but that doesn't tell you the individual masses of the stars, which is what you really want to know. That takes one more step. To find the total mass of a binary star system, you must know the size of the orbits and the orbital period—the length of time the stars take to complete one orbit. The smaller the orbits are and the shorter the orbital period is, the stronger the stars' gravity must be to hold each other in orbit. From the sizes of the orbits and the orbital period, astronomers can use Kepler's third law (see Section 3-3c of Chapter 3) to figure out how much mass the stars contain in total. Combining that information with the ratio of the masses found from the relative sizes of the orbits reveals the individual masses of the stars. Finding the mass of a binary star system is easier said than done. One difficulty is that the true sizes of the star orbits must be measured in units, such as meters or Astronomical Units, in order to find the masses of the stars in units such as kilograms or solar masses. Measuring the true sizes of the orbits in turn requires knowing the distance to the binary system. Therefore, the only stars whose masses astronomers know for certain are in binary systems with orbits that have been determined and distances from Earth that have been measured. Other complications are that the orbits of the two stars may be elliptical; also, the plane of their orbits can be tipped at an angle to your line of sight, distorting the apparent shapes of the orbits. Astronomers must find ways to correct for these complications.

Electron-positron annihilation byproducts

Electron-positron annihilation occurs when an electron (e−) and a positron (e+, the electron's antiparticle) collide. At low energies, the result of the collision is the annihilation of the electron and positron, and the creation of energetic photons: e− + e+ → γ + γ At high energies, other particles, such as B mesons or the W and Z bosons, can be created. All processes must satisfy a number of conservation laws, including:

emission nebula

Emission nebulae are produced when a hot star excites the gas near it to produce an emission spectrum. The star must be hotter than about spectral type B1 (25,000 K). Cooler stars do not emit enough ultraviolet radiation to ionize the gas. Emission nebulae have a distinctive pink color produced by the blending of the red, blue, and violet Balmer lines. Emission nebulae are also called H II regions, following the convention of using Roman numerals to indicate an atom's ionization state. Thus, H I means neutral hydrogen; H II is ionized. In an H II region, the ionized nuclei and free electrons are mixed. When a nucleus captures an electron, the electron falls down through the atomic energy levels, emitting photons at specific wavelengths. Spectra indicate that the nebulae have compositions much like that of the Sun—mostly hydrogen. Emission nebulae have densities of 100 to 1000 atoms per cubic centimeter, thinner than the best vacuums produced in laboratories on Earth.

energy transport

Energy moves from hot to cool regions by conduction, radiation, or convection.

Piles of dead and rotting piglets are piled up behind a sow, who is wedged into a crate so tightly that she cannot move away from the mess at Smithfield-owned Circle Four Farm in Utah. Photo: Wayne Hsiung/DxE

Female pigs give birth in this condition. They are put in so-called farrowing crates when they give birth, and their piglets run underneath them to suckle and are often trampled to death. The sows are bred repeatedly this way until their fertility declines, at which point they are slaughtered and turned into meat.

Cytosol

Fluid portion of cytoplasm The cytosol, also known as intracellular fluid (ICF) or cytoplasmic matrix, or groundplasm,[2] is the liquid found inside cells.[3] It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into many compartments. In the eukaryotic cell, the cytosol is surrounded by the cell membrane and is part of the cytoplasm, which also comprises the mitochondria, plastids, and other organelles (but not their internal fluids and structures); the cell nucleus is separate. The cytosol is thus a liquid matrix around the organelles. In prokaryotes, most of the chemical reactions of metabolism take place in the cytosol, while a few take place in membranes or in the periplasmic space. In eukaryotes, while many metabolic pathways still occur in the cytosol, others take place within organelles. The cytosol is a complex mixture of substances dissolved in water. Although water forms the large majority of the cytosol, its structure and properties within cells is not well understood. The concentrations of ions such as sodium and potassium are different in the cytosol than in the extracellular fluid; these differences in ion levels are important in processes such as osmoregulation, cell signaling, and the generation of action potentials in excitable cells such as endocrine, nerve and muscle cells. The cytosol also contains large amounts of macromolecules, which can alter how molecules behave, through macromolecular crowding.

nova

From the Latin, meaning "new," a sudden and temporary brightening of a star making it appear as a new star in the sky, evidently caused by an explosion of nuclear fuel on the surface of a white dwarf stellar remnant.

Gram-negative bacteria

Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation.[1] They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane.

Granule

Granules on the photosphere of the Sun are caused by convection currents (thermal columns, Bénard cells) of plasma within the Sun's convective zone. The grainy appearance of the solar photosphere is produced by the tops of these convective cells and is called granulation. The rising part of the granules is located in the center where the plasma is hotter. The outer edge of the granules is darker due to the cooler descending plasma. (The terms darker and cooler are strictly by comparison to the brighter, hotter plasma. Since luminosity increases with the fourth power of temperature, even a small loss of heat produces a large luminosity contrast; this "cooler", "darker" plasma is still far hotter and vastly brighter than a thermite reaction.) In addition to the visible appearance, which would be explained by convective motion, Doppler shift measurements of the light from individual granules provides evidence for the convective nature of the granules. A typical granule has a diameter on the order of 1,500 kilometres (930 mi)[1] and lasts 8 to 20 minutes before dissipating.[2] At any one time, the Sun's surface is covered by about 4 million granules. Below the photosphere is a layer of "supergranules" up to 30,000 kilometres (19,000 mi) in diameter with lifespans of up to 24 hours.

Koko

Hanabiko "Koko" (July 4, 1971 - June 19, 2018) was a female western lowland gorilla known for having learned many hand signs from a modified version of American Sign Language (ASL). Koko was born at the San Francisco Zoo and lived most of her life in Woodside, California. Her instructor and caregiver, Francine Patterson, reported that Koko had an active vocabulary of more than 1,000 signs of what Patterson calls "Gorilla Sign Language" (GSL).[4][5] This puts Koko's vocabulary at the same level as a 3 year old human.[6] In contrast to other experiments attempting to teach sign language to non-human primates, Patterson simultaneously exposed Koko to spoken English from an early age. It was reported that Koko understood approximately 2,000 words of spoken English, in addition to the signs.[7] Koko's life and learning process has been described by Patterson and various collaborators in books, peer-reviewed scientific articles, and on a website. After Patterson's research with Koko was completed, the gorilla moved to a reserve in Woodside, California. At the reserve, Koko lived with another gorilla, Michael, who also learned sign language, but he died in 2000. She then lived with another male gorilla, Ndume,[20] until her death. Koko was reported to have a preoccupation with both male and female human nipples, with several people saying that Koko requested to see their nipples. In 2005, three staff at The Gorilla Foundation, where Koko resided, filed lawsuits against the organization, alleging that they were pressured to reveal their nipples to Koko by the organization's executive director, among other violations of labor law. The lawsuits were settled out of court. Gorilla expert Kristen Lukas has said that other gorillas are not known to have had a similar nipple fixation. Koko died in her sleep during the morning of June 19, 2018, at the Gorilla Foundation's preserve in Woodside, California, at the age of 46. Patterson reported that Koko made several complex uses of signs that suggested a more developed degree of cognition than is usually attributed to non-human primates and their use of communication. For example, Koko was reported to use displacement (the ability to communicate about objects that are not currently present).[34] At age 19, Koko was able to pass the mirror test of self-recognition, which most other gorillas fail.[35][36] She had been reported to relay personal memories.[37] Koko was reported to use meta-language, being able to use language reflexively to speak about language itself, signing "good sign" to another gorilla who successfully used signing.[38] Koko was reported to use language deceptively, and to use counterfactual statements for humorous effects, suggesting an underlying theory of other minds. Patterson reported that she documented Koko inventing new signs to communicate novel thoughts. For example, she said that nobody taught Koko the word for "ring", but to refer to it, Koko combined the words "finger" and "bracelet", hence "finger-bracelet".

Herbig-Haro objects

Herbig-Haro (HH) objects are bright patches of nebulosity associated with newborn stars. They are formed when narrow jets of partially ionised gas ejected by stars collide with nearby clouds of gas and dust at several hundred kilometres per second. Herbig-Haro objects are commonly found in star-forming regions, and several are often seen around a single star, aligned with its rotational axis. Most of them lie within about one parsec (3.26 light-years) of the source, although some have been observed several parsecs away. HH objects are transient phenomena that last around a few tens of thousands of years. They can change visibly over timescales of a few years as they move rapidly away from their parent star into the gas clouds of interstellar space (the interstellar medium or ISM). Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a few years, as parts of the nebula fade while others brighten as they collide with the clumpy material of the interstellar medium.

Ruminant

Hooved animals that have a rumen and chew their cud Ruminants are mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process, which takes place in the front part of the digestive system and therefore is called foregut fermentation, typically requires the fermented ingesta (known as cud) to be regurgitated and chewed again. The process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination.[1][2] The word "ruminant" comes from the Latin ruminare, which means "to chew over again". Ruminants' mouths often smell of moist grass that is beginning to decompose. The first two chambers are the rumen and the reticulum. These two compartments make up the fermentation vat, they are the major site of microbial activity. Fermentation is crucial to digestion because it breaks down complex carbohydrates, such as cellulose, and enables the animal to utilize them. Microbes function best in a warm, moist, anaerobic environment with a temperature range of 37.7 to 42.2 °C (100 to 108 °F) and a pH between 6.0 and 6.4. Without the help of microbes, ruminants would not be able to utilize nutrients from forages.[11] The food is mixed with saliva and separates into layers of solid and liquid material.[12] Solids clump together to form the cud or bolus. The cud is then regurgitated and chewed to completely mix it with saliva and to break down the particle size. Smaller particle size allows for increased nutrient absorption. Fiber, especially cellulose and hemicellulose, is primarily broken down in these chambers by microbes (mostly bacteria, as well as some protozoa, fungi, and yeast) into the three volatile fatty acids (VFAs): acetic acid, propionic acid, and butyric acid. Protein and nonstructural carbohydrate (pectin, sugars, and starches) are also fermented. Saliva is very important because it provides liquid for the microbial population, recirculates nitrogen and minerals, and acts as a buffer for the rumen pH.[11] The type of feed the animal consumes affects the amount of saliva that is produced. Though the rumen and reticulum have different names, they have very similar tissue layers and textures, making it difficult to visually separate them. They also perform similar tasks. Together, these chambers are called the reticulorumen. The degraded digesta, which is now in the lower liquid part of the reticulorumen, then passes into the next chamber, the omasum. This chamber controls what is able to pass into the abomasum. It keeps the particle size as small as possible in order to pass into the abomasum. The omasum also absorbs volatile fatty acids and ammonia.[11]

Milky Way Gamma- and X-ray emitting Fermi bubbles

In November 2010, it was announced that two gamma-ray and X-ray emitting bubbles were detected around Earth's galaxy, the Milky Way.[54] The bubbles, named Fermi bubbles, extend about 25 thousand light-years distant above and below the galactic center.[54] The galaxy's diffuse gamma-ray fog hampered prior observations, but the discovery team led by D. Finkbeiner, building on research by G. Dobler, worked around this problem. The gamma rays are created by inverse compton scattering which just means that low energy photons bounce off high energy electrons. The energy is then transferred from the electron to the photon to make a high energy gamma ray.

Triple star systems

In a physical triple star system, each star orbits the center of mass of the system. Usually, two of the stars form a close binary system, and the third orbits this pair at a distance much larger than that of the binary orbit. This arrangement is called hierarchical. The reason for this is that if the inner and outer orbits are comparable in size, the system may become dynamically unstable, leading to a star being ejected from the system.[17] Triple stars that are not all gravitationally bound might comprise a physical binary and an optical companion, such as Beta Cephei, or rarely, a purely optical triple star, such as Gamma Serpentis.

Somatic Cell Nuclear Transfer (SCNT)

In genetics and developmental biology, somatic cell nuclear transfer (SCNT) is a laboratory strategy for creating a viable embryo from a body cell and an egg cell. The technique consists of taking an enucleated oocyte (egg cell) and implanting a donor nucleus from a somatic (body) cell. It is used in both therapeutic and reproductive cloning. In 1996, Dolly the sheep became famous for being the first successful case of the reproductive cloning of a mammal. The process of somatic cell nuclear transplant involves two different cells. The first being a female gamete, known as the ovum (egg/oocyte). In human SCNT (Somatic Cell Nuclear Transfer) experiments, these eggs are obtained through consenting donors, utilizing ovarian stimulation. The second being a somatic cell, referring to the cells of the human body. Skin cells, fat cells, and liver cells are only a few examples. The genetic material of the donor egg cell is removed and discarded, leaving it 'deprogrammed.' What is left is a somatic cell and an enucleated egg cell. These are then fused by inserting the somatic cell into the 'empty' ovum. After being inserted into the egg, the somatic cell nucleus is reprogrammed by its host egg cell. The ovum, now containing the somatic cell's nucleus, is stimulated with a shock and will begin to divide. The egg is now viable and capable of producing an adult organism containing all the necessary genetic information from just one parent. Development will ensue normally and after many mitotic divisions, this single cell forms a blastocyst (an early stage embryo with about 100 cells) with an identical genome to the original organism (i.e. a clone).[6] Stem cells can then be obtained by the destruction of this clone embryo for use in therapeutic cloning or in the case of reproductive cloning the clone embryo is implanted into a host mother for further development and brought to term. SCNT can be inefficient. Stresses placed on both the egg cell and the introduced nucleus in early research were enormous, resulting in a low percentage of successfully reprogrammed cells. For example, in 1996 Dolly the sheep was born after 277 eggs were used for SCNT, which created 29 viable embryos. Only three of these embryos survived until birth, and only one survived to adulthood.[25] As the procedure was not automated, but had to be performed manually under a microscope, SCNT was very resource intensive. The biochemistry involved in reprogramming the differentiated somatic cell nucleus and activating the recipient egg was also far from understood. However, by 2014, researchers were reporting success rates of 70-80% with cloning pigs[36] and in 2016 a Korean company, Sooam Biotech, was reported to be producing 500 cloned embryos a day.[37] interesting wiki page https://en.wikipedia.org/wiki/Somatic_cell_nuclear_transfer

Mutagen

In genetics, a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer, mutagens are therefore also likely to be carcinogens, although not always necessarily so. All mutagens have characteristic mutational signatures with some chemicals becoming mutagenic through cellular processes. Not all mutations are caused by mutagens: so-called "spontaneous mutations" occur due to spontaneous hydrolysis, errors in DNA replication, repair and recombination.

Transcription factor

In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence.[1][2] The function of TFs is to regulate—turn on and off—genes in order to make sure that they are expressed in the right cell at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are up to 1600 TFs in the human genome. TFs work alone or with other proteins in a complex, by promoting (as an activator), or blocking (as a repressor) the recruitment of RNA polymerase (the enzyme that performs the transcription of genetic information from DNA to RNA) to specific genes. A defining feature of TFs is that they contain at least one DNA-binding domain (DBD), which attaches to a specific sequence of DNA adjacent to the genes that they regulate.[7][8] TFs are grouped into classes based on their DBDs.[9][10] Other proteins such as coactivators, chromatin remodelers, histone acetyltransferases, histone deacetylases, kinases, and methylases are also essential to gene regulation, but lack DNA-binding domains, and therefore are not TFs.

Electrophile

In organic chemistry, an electrophile is an electron pair acceptor. Electrophiles are positively charged or neutral species having vacant orbitals that are attracted to an electron rich centre. It participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile. electrophilic

how long can tardigrades stay in cryptobiosis?

In these extreme environments, the animals will enter a type of hibernation called cryptobiosis, in which they recoil into a compact, dried ball and stay dormant for an indefinite period of time. A few years ago, a thawed tardigrade survived after being frozen for 30 years. Probably can stay dormant longer than that.

incinerator

Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials.[1] Incineration and other high-temperature waste treatment systems are described as "thermal treatment". Incineration of waste materials converts the waste into ash, flue gas and heat. The ash is mostly formed by the inorganic constituents of the waste and may take the form of solid lumps or particulates carried by the flue gas. The flue gases must be cleaned of gaseous and particulate pollutants before they are dispersed into the atmosphere. In some cases, the heat generated by incineration can be used to generate electric power. Incinerators reduce the solid mass of the original waste by 80%-85% and the volume (already compressed somewhat in garbage trucks) by 95%-96%, depending on composition and degree of recovery of materials such as metals from the ash for recycling.[2] This means that while incineration does not completely replace landfilling, it significantly reduces the necessary volume for disposal. Waste combustion is particularly popular in countries such as Japan, Singapore and the Netherlands, where land is a scarce resource. Denmark and Sweden have been leaders by using the energy generated from incineration for more than a century, in localised combined heat and power facilities supporting district heating schemes.[3] In 2005, waste incineration produced 4.8% of the electricity consumption and 13.7% of the total domestic heat consumption in Denmark.[4] A number of other European countries rely heavily on incineration for handling municipal waste, in particular Luxembourg, the Netherlands, Germany, and France. The typical incineration plant for municipal solid waste is a moving grate incinerator. The moving grate enables the movement of waste through the combustion chamber to be optimized to allow a more efficient and complete combustion. A single moving grate boiler can handle up to 35 metric tons (39 short tons) of waste per hour, and can operate 8,000 hours per year with only one scheduled stop for inspection and maintenance of about one month's duration. Moving grate incinerators are sometimes referred to as Municipal Solid Waste Incinerators (MSWIs). The flue gases are then cooled in the superheaters, where the heat is transferred to steam, heating the steam to typically 400 °C (752 °F) at a pressure of 40 bars (580 psi) for the electricity generation in the turbine. At this point, the flue gas has a temperature of around 200 °C (392 °F), and is passed to the flue gas cleaning system. The concerns over the health effects of dioxin and furan emissions have been significantly lessened by advances in emission control designs and very stringent new governmental regulations that have resulted in large reductions in the amount of dioxins and furans emissions.[16]

how old are the pyramids?

Introduction. Archaeologists believe Egypt's large pyramids are the work of the Old Kingdom society that rose to prominence in the Nile Valley after 3000 B.C. Historical analysis tells us that the Egyptians built the Giza Pyramids in a span of 85 years between 2589 and 2504 BC.

the golden spoon

It's basically a silver spoon, meaning someone was born with privilege and wealth. They didn't have to work for it, and it was given unconditionally. But, a golden spoon.

Lampreys

Lampreys are an ancient extant lineage of jawless fish of the order Petromyzontiformes, placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. There are about 38 known extant species of lampreys and five known extinct species.

st peter's basilica

Largest Christian church in the world. Located in the Vatican City in Italy. The dome was created by Michelangelo.

Microfungi

Microfungi are fungi— eukaryotic organisms such as molds, mildews and rusts— which exhibit tube tip-growth and have cell walls composed of chitin, a polymer of N-acetylglucosamine. a fungus in which no sexual process has been observed or in which the reproductive organs are microscopic.

Small farmers across the globe are losing out in the aftermath of the African swine fever (ASF) outbreak that killed a quarter of the world's pig population, argues a new report. After the first notification of the ASF outbreak in China in August 2018, the illness spread rapidly throughout the industry and led to the slaughter of millions of pigs within months.

Millions of pigs were killed, many by being buried alive, in China following the 2018 outbreak. Photograph: Reuters In a MARA survey of 1,500 Chinese pig farms in mid-2019, 55% said they had abandoned plans to raise pigs after culling due to future risk of disease, while 22% were waiting to see if the situation cleared up. Only 18% had definite plans to continue pig farming.

computer driver

More commonly known as a driver, a device driver or hardware driver is a group of files that enable one or more hardware devices to communicate with the computer's operating system. Without drivers, the computer would not be able to send and receive data correctly to hardware devices, such as a printer.

how many animals are slaughtered for meat each year?

More than 150 billion.

Yukawa potential

No idea. Supposed to be related to coulomb potential somehow. In interactions between a meson field and a fermion field, the constant g is equal to the gauge coupling constant between those fields. In the case of the nuclear force, the fermions would be a proton and another proton or a neutron.

The Pressure-Temperature Thermostat of Stars

Nuclear reactions in stars manufacture energy and heavy atoms under the supervision of a natural thermostat that keeps the reactions from erupting out of control. That thermostat is the relation between gas pressure and temperature. In a star, the nuclear reactions generate just enough energy to balance the inward pull of gravity. Consider what would happen if the reactions began to produce too much energy. The star balances gravity by generating energy, so the extra energy flowing out of the star would force it to expand. The expansion would lower the central temperature and density and slow the nuclear reactions until the star regained stability. Thus the star has a built-in regulator that keeps the nuclear reactions from occurring too rapidly. The same thermostat keeps the reactions from dying down. Suppose the nuclear reactions began making too little energy. Then the star would contract slightly, increasing the central temperature and density and increasing the nuclear energy generation. The overall stability of a star depends on the relation between gas pressure and temperature. If the material of the star has the property of normal gases—for which an increase or decrease in temperature produces a corresponding change in pressure—then the nuclear reaction pressure-temperature thermostat can function properly and contribute to the stability of the star. In the next section of this chapter, you will see how this thermostat accounts for the relation between mass and luminosity for main-sequence stars.

Nucleation

Nucleation is the first step in the formation of either a new thermodynamic phase or a new structure via self-assembly or self-organization. Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organized structure appears. For example, if a volume of water is cooled (at atmospheric pressure) below 0 °C, it will tend to freeze into ice, but volumes of water cooled only a few degrees below 0 °C often stay completely free of ice for long periods. At these conditions, nucleation of ice is either slow or does not occur at all. However, at lower temperatures ice crystals appear after little or no delay. At these conditions ice nucleation is fast.[1][2] Nucleation is commonly how first-order phase transitions start, and then it is the start of the process of forming a new thermodynamic phase. In contrast, new phases at continuous phase transitions start to form immediately. Nucleation is often found to be very sensitive to impurities in the system. These impurities may be too small to be seen by the naked eye, but still can control the rate of nucleation. Because of this, it is often important to distinguish between heterogeneous nucleation and homogeneous nucleation. Heterogeneous nucleation occurs at nucleation sites on surfaces in the system.[1] Homogeneous nucleation occurs away from a surface. Image: When sugar is supersaturated in water, nucleation will occur, allowing sugar molecules to stick together and form large crystal structures. Supersaturation is a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances. It can also refer to a vapor of a compound that has a higher (partial) pressure than the vapor pressure of that compound.

artificial nucleotides

Nucleic acid analogues are compounds which are analogous (structurally similar) to naturally occurring RNA and DNA, used in medicine and in molecular biology research. Nucleic acids are chains of nucleotides, which are composed of three parts: a phosphate backbone, a pentose sugar, either ribose or deoxyribose, and one of four nucleobases. An analogue may have any of these altered.[1] Typically the analogue nucleobases confer, among other things, different base pairing and base stacking properties. Examples include universal bases, which can pair with all four canonical bases, and phosphate-sugar backbone analogues such as PNA, which affect the properties of the chain (PNA can even form a triple helix).[2] Nucleic acid analogues are also called Xeno Nucleic Acid and represent one of the main pillars of xenobiology, the design of new-to-nature forms of life based on alternative biochemistries. Artificial nucleic acids include peptide nucleic acid (PNA), Morpholino and locked nucleic acid (LNA), as well as glycol nucleic acid (GNA) and threose nucleic acid (TNA). Each of these is distinguished from naturally occurring DNA or RNA by changes to the backbone of the molecule. In May 2014, researchers announced that they had successfully introduced two new artificial nucleotides into bacterial DNA, and by including individual artificial nucleotides in the culture media, were able to passage the bacteria 24 times; they did not create mRNA or proteins able to use the artificial nucleotides. The artificial nucleotides featured 2 fused aromatic rings. ________________ Romesberg says his lab spent 15 years developing DNA with two extra letters. In chemical terms, the letters are nucleotides, the components of DNA whose sequences spell out instructions for making proteins. Cells, you may remember, make proteins by transcribing DNA into RNA and using the RNA as a template to string together amino acids into proteins. Cells also have to copy their DNA each time they divide to make more cells. The biggest challenge, Romesberg says, was making sure the two new nucleotides played nice with the enzymes that do all this copying and transcribing. But could six-letter DNA actually function in the far more complex and chaotic environment of a living cell? The new study suggests it can. Romesberg and colleagues managed to coax E. coli bacteria into taking up their six-letter DNA and making copies of it. The cells' enzymes copied the two new letters, which the scientists call X and Y for short (not to be confused with the X and Y chromosomes that differentiate boys from girls), along with the usual four. The cells grew a little more slowly than normal, but otherwise seemed no worse for wear, the team reports today in Nature. The next steps, Romesberg says, will be to determine whether cells can also transcribe the unnatural base pairs into RNA, and, ultimately, use them to make proteins. With a bigger genetic alphabet, cells could potentially encode synthetic amino acids not found in nature and make novel proteins that would be difficult-if not impossible-to synthesize directly. It should also be possible to trick synthetic cells into evolving proteins or other molecules that are optimized for various biological tasks, Romesberg says. He has started a company, Synthorx, to explore these possibilities.

Ocean Fish Numbers Cut in Half Since 1970

OSLO, Sept 16 (Reuters) - The amount of fish in the oceans has halved since 1970, in a plunge to the "brink of collapse" caused by overfishing and other threats, the WWF conservation group said on Wednesday. The report said populations of fish, marine mammals, birds and reptiles had fallen 49 percent between 1970 and 2012. For fish alone, the decline was 50 percent. The analysis said it tracked 5,829 populations of 1,234 species, such as seals, turtles and dolphins and sharks. It said the ZSL data sets were almost twice as large as past studies. "This report suggests that billions of animals have been lost from the world's oceans in my lifetime alone," Ken Norris, director of science at the ZSL, said in a statement. "This is a terrible and dangerous legacy to leave to our grandchildren." Damage to coral reefs and mangroves, which are nurseries for many fish, add to problems led by over-fishing. Other threats include coastal development, pollution and climate change, which is raising temperatures and making waters more acidic.

Bioreactor

Organisms growing in bioreactors may be submerged in liquid medium or may be attached to the surface of a solid medium. Submerged cultures may be suspended or immobilized. Suspension bioreactors can use a wider variety of organisms, since special attachment surfaces are not needed, and can operate at a much larger scale than immobilized cultures. However, in a continuously operated process the organisms will be removed from the reactor with the effluent. Immobilization is a general term describing a wide variety of methods for cell or particle attachment or entrapment.[3] It can be applied to basically all types of biocatalysis including enzymes, cellular organelles, animal and plant cells.[4] Immobilization is useful for continuously operated processes, since the organisms will not be removed with the reactor effluent, but is limited in scale because the microbes are only present on the surfaces of the vessel. A photobioreactor (PBR) is a bioreactor which incorporates some type of light source (that may be natural sunlight or artificial illumination). Virtually any translucent container could be called a PBR, however the term is more commonly used to define a closed system, as opposed to an open storage tank or pond. Photobioreactors are used to grow small phototrophic organisms such as cyanobacteria, algae, or moss plants.[5] These organisms use light through photosynthesis as their energy source and do not require sugars or lipids as energy source. Consequently, risk of contamination with other organisms like bacteria or fungi is lower in photobioreactors when compared to bioreactors for heterotroph organisms.[citation needed] Conventional sewage treatment utilises bioreactors to undertake the main purification processes. In some of these systems, a chemically inert medium with very high surface area is provided as a substrate for the growth of biological film. Separation of excess biological film takes place in settling tanks or cyclones. In other systems aerators supply oxygen to the sewage and biota to create activated sludge in which the biological component is freely mixed in the liquor in "flocs". In these processes, the liquid's Biochemical Oxygen Demand (BOD) is reduced sufficiently to render the contaminated water fit for reuse. The biosolids can be collected for further processing, or dried and used as fertilizer. An extremely simple version of a sewage bioreactor is a septic tank whereby the sewage is left in situ, with or without additional media to house bacteria. In this instance, the biosludge itself is the primary host for the bacteria.[citation needed]

Peptidoglycan

Peptidoglycan is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall. The sugar component consists of alternating residues of β- linked N-acetylglucosamine and N-acetylmuramic acid. a substance forming the cell walls of many bacteria, consisting of glycosaminoglycan chains interlinked with short peptides.

How to detect exoplanets?

Planets gravitationally pull on the star which will cause a doppler shift to its spectra. You can also detect them by gravitational lensing or changes in luminosity. You will remember that Earth and its Moon orbit around their common center of mass, and two stars in a binary system orbit around their center of mass. When a planet orbits a star, the star moves very slightly as it orbits the center of mass of the planet-star system. Think of someone walking a poorly trained dog on a leash; the dog runs around pulling on the leash, and even if it were an invisible dog, you could plot its path by watching how its owner was jerked back and forth. Astronomers can detect a planet orbiting another star by watching how the star moves as the planet tugs on it. The first planet orbiting a Sun-like star detected this way was discovered in 1995. It orbits the star 51 Pegasi. As the planet circles the star, the star wobbles slightly, and this very small motion of the star is detectable as Doppler shifts in the star's spectrum, as shown in Figure 8-14a. This is the same technique used to study spectroscopic binary stars (see Chapter 9). From the motion of the star and estimates of the star's mass, astronomers can deduce that the planet has half the mass of Jupiter and orbits only 0.05 AU from the star. Half the mass of Jupiter amounts to 160 Earth masses, so this is a large planet, larger than Saturn. Note also that it orbits very close to its star

Recombinant DNA

Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.

Artificial cloning of organisms

Reproductive cloning generally uses "somatic cell nuclear transfer" (SCNT) to create animals that are genetically identical. This process entails the transfer of a nucleus from a donor adult cell (somatic cell) to an egg from which the nucleus has been removed, or to a cell from a blastocyst from which the nucleus has been removed.[23] If the egg begins to divide normally it is transferred into the uterus of the surrogate mother. Such clones are not strictly identical since the somatic cells may contain mutations in their nuclear DNA. Additionally, the mitochondria in the cytoplasm also contains DNA and during SCNT this mitochondrial DNA is wholly from the cytoplasmic donor's egg, thus the mitochondrial genome is not the same as that of the nucleus donor cell from which it was produced. This may have important implications for cross-species nuclear transfer in which nuclear-mitochondrial incompatibilities may lead to death. Artificial embryo splitting or embryo twinning, a technique that creates monozygotic twins from a single embryo, is not considered in the same fashion as other methods of cloning. During that procedure, a donor embryo is split in two distinct embryos, that can then be transferred via embryo transfer. It is optimally performed at the 6- to 8-cell stage, where it can be used as an expansion of IVF to increase the number of available embryos.[24] If both embryos are successful, it gives rise to monozygotic (identical) twins. Dolly, a Finn-Dorset ewe, was the first mammal to have been successfully cloned from an adult somatic cell. Dolly was formed by taking a cell from the udder of her 6-year-old biological mother.[25] Dolly's embryo was created by taking the cell and inserting it into a sheep ovum. It took 434 attempts before an embryo was successful.[26] The embryo was then placed inside a female sheep that went through a normal pregnancy.[27] She was cloned at the Roslin Institute in Scotland by British scientists Sir Ian Wilmut and Keith Campbell and lived there from her birth in 1996 until her death in 2003 when she was six. She was born on 5 July 1996 but not announced to the world until 22 February 1997.[28] Her stuffed remains were placed at Edinburgh's Royal Museum, part of the National Museums of Scotland.[29] Species cloned Carp: (1963) In China, embryologist Tong Dizhou produced the world's first cloned fish by inserting the DNA from a cell of a male carp into an egg from a female carp. He published the findings in a Chinese science journal.[35] Sheep: Marked the first mammal being cloned (1984) from early embryonic cells by Steen Willadsen. Megan and Morag[36] cloned from differentiated embryonic cells in June 1995 and Dolly the sheep from a somatic cell in 1996.[37][35] Gaur: (2001) was the first endangered species cloned.[44] Looks like an indian bison Camel: (2009) Injaz, is the first cloned camel.[55] Macaque monkey: (2017) First successful cloning of a primate species using nuclear transfer, with the birth of two live clones, named Zhong Zhong and Hua Hua. Conducted in China in 2017, and reported in January 2018.[59][60][61][62] In January 2019, scientists in China reported the creation of five identical cloned gene-edited monkeys, using the same cloning technique that was used with Zhong Zhong and Hua Hua and Dolly the sheep, and the same gene-editing Crispr-Cas9 technique allegedly used by He Jiankui in creating the first ever gene-modified human babies Lulu and Nana. The monkey clones were made in order to study several medical diseases. __________________ Two commonly discussed types of theoretical human cloning are therapeutic cloning and reproductive cloning. Therapeutic cloning would involve cloning cells from a human for use in medicine and transplants, and is an active area of research, but is not in medical practice anywhere in the world, as of 2014. Two common methods of therapeutic cloning that are being researched are somatic-cell nuclear transfer and, more recently, pluripotent stem cell induction. Reproductive cloning would involve making an entire cloned human, instead of just specific cells or tissues.[66]

Salmon

Salmon are native to tributaries of the North Atlantic (genus Salmo) and Pacific Ocean (genus Oncorhynchus). Many species of salmon have been introduced into non-native environments such as the Great Lakes of North America and Patagonia in South America. Salmon are intensively farmed in many parts of the world. There are six types of Salmon in North America. Five come from the Pacific coast and are called Pacific Salmon. These are Chinook, Coho, Sockeye, Pink, and Chum Salmon. The other one traditionally lives in the Atlantic and is simply called Atlantic Salmon. Where does most salmon you eat come from? This means that the two leading producer countries, Norway and Chile currently make up over 80 % of total production. With production shares in parentheses, Scotland (7.4 % ), Canada (5.7 % ) and the Faroe Islands (2.7 % ) round out the five leading producer countries. Typically, salmon are anadromous: they hatch in fresh water, migrate to the ocean, then return to fresh water to reproduce. However, populations of several species are restricted to fresh water through their lives. Folklore has it that the fish return to the exact spot where they hatched to spawn. Tracking studies have shown this to be mostly true. A portion of a returning salmon run may stray and spawn in different freshwater systems; the percent of straying depends on the species of salmon. Although most adult Pacific salmon feed on small fish, shrimp, and squid, sockeye feed on plankton they filter through gill rakers. _________ Salmon eggs are laid in freshwater streams typically at high latitudes. The eggs hatch into alevin or sac fry. The fry quickly develop into parr with camouflaging vertical stripes. The parr stay for six months to three years in their natal stream before becoming smolts, which are distinguished by their bright, silvery colour with scales that are easily rubbed off. Only 10% of all salmon eggs are estimated to survive to this stage. The smolt body chemistry changes, allowing them to live in salt water. While a few species of salmon remain in fresh water throughout their life cycle, the majority are anadromous and migrate to the ocean for maturation: in these species, smolts spend a portion of their out-migration time in brackish water, where their body chemistry becomes accustomed to osmoregulation in the ocean. The salmon spend about one to five years (depending on the species) in the open ocean, where they gradually become sexually mature. The adult salmon then return primarily to their natal streams to spawn. Atlantic salmon spend between one and four years at sea. When a fish returns after just one year's sea feeding, it is called a grilse in Canada, Britain, and Ireland. Grilse may be present at spawning, and go unnoticed by large males, releasing their own sperm on the eggs. Prior to spawning, depending on the species, salmon undergo changes. They may grow a hump, develop canine-like teeth, or develop a kype (a pronounced curvature of the jaws in male salmon). All change from the silvery blue of a fresh-run fish from the sea to a darker colour. Salmon can make amazing journeys, sometimes moving hundreds of miles upstream against strong currents and rapids to reproduce. Chinook and sockeye salmon from central Idaho, for example, travel over 1,400 km (900 mi) and climb nearly 2,100 m (7,000 ft) from the Pacific Ocean as they return to spawn. Condition tends to deteriorate the longer the fish remain in fresh water, and they then deteriorate further after they spawn, when they are known as kelts. In all species of Pacific salmon, the mature individuals die within a few days or weeks of spawning, a trait known as semelparity. Between 2 and 4% of Atlantic salmon kelts survive to spawn again, all females. However, even in those species of salmon that may survive to spawn more than once (iteroparity), postspawning mortality is quite high (perhaps as high as 40 to 50%). To lay her roe, the female salmon uses her tail (caudal fin), to create a low-pressure zone, lifting gravel to be swept downstream, excavating a shallow depression, called a redd. The redd may sometimes contain 5,000 eggs covering 2.8 m2 (30 sq ft).[51] The eggs usually range from orange to red. One or more males approach the female in her redd, depositing sperm, or milt, over the roe.[48] The female then covers the eggs by disturbing the gravel at the upstream edge of the depression before moving on to make another redd. The female may make as many as seven redds before her supply of eggs is exhausted.' A female may lay between 2000-5000 eggs before she is senescent (spawned out) and dies. Freshwater streams and estuaries provide important habitat for many salmon species. They feed on terrestrial and aquatic insects, amphipods, and other crustaceans while young, and primarily on other fish when older. Eggs are laid in deeper water with larger gravel, and need cool water and good water flow (to supply oxygen) to the developing embryos. Mortality of salmon in the early life stages is usually high due to natural predation and human-induced changes in habitat, such as siltation, high water temperatures, low oxygen concentration, loss of stream cover, and reductions in river flow. Estuaries and their associated wetlands provide vital nursery areas for the salmon prior to their departure to the open ocean. Wetlands not only help buffer the estuary from silt and pollutants, but also provide important feeding and hiding areas. Salmon not killed by other means show greatly accelerated deterioration (phenoptosis, or "programmed aging") at the end of their lives. Their bodies rapidly deteriorate right after they spawn as a result of the release of massive amounts of corticosteroids. In the Pacific Northwest and Alaska, salmon are keystone species, supporting wildlife such as birds, bears and otters.[52] The bodies of salmon represent a transfer of nutrients from the ocean, rich in nitrogen, sulfur, carbon and phosphorus, to the forest ecosystem. Grizzly bears function as ecosystem engineers, capturing salmon and carrying them into adjacent wooded areas. There they deposit nutrient-rich urine and feces and partially eaten carcasses. Bears are estimated to leave up to half the salmon they harvest on the forest floor,[53][54] in densities that can reach 4,000 kilograms per hectare,[55] providing as much as 24% of the total nitrogen available to the riparian woodlands. The foliage of spruce trees up to 500 m (1,600 ft) from a stream where grizzlies fish salmon have been found to contain nitrogen originating from fished salmon.[56] Beavers also function as ecosystem engineers; in the process of clear-cutting and damming, beavers alter their ecosystems extensively. Beaver ponds can provide critical habitat for juvenile salmon. An example of this was seen in the years following 1818 in the Columbia River Basin. In 1818, the British government made an agreement with the U.S. government to allow U.S. citizens access to the Columbia catchment (see Treaty of 1818). At the time, the Hudson's Bay Company sent word to trappers to extirpate all furbearers from the area in an effort to make the area less attractive to U.S. fur traders. In response to the elimination of beavers from large parts of the river system, salmon runs plummeted, even in the absence of many of the factors usually associated with the demise of salmon runs. Salmon recruitment can be affected by beavers' dams because dams can: - Slow the rate at which nutrients are flushed from the system; nutrients provided by adult salmon dying throughout the fall and winter remain available in the spring to newly hatched juveniles - Provide deeper water pools where young salmon can avoid avian predators - Increase productivity through photosynthesis and by enhancing the conversion efficiency of the cellulose-powered detritus cycle - Create slow-water environments where juvenile salmon put the food they ingest into growth rather than into fighting currents - Increase structural complexity with many physical niches where salmon can avoid predators Beavers' dams are able to nurture salmon juveniles in estuarine tidal marshes where the salinity is less than 10 ppm. Beavers build small dams of generally less than 60 cm (2 ft) high in channels in the myrtle zone. These dams can be overtopped at high tide and hold water at low tide. This provides refuges for juvenile salmon so they do not have to swim into large channels where they are subject to predation. Lampreys and salmon It has been discovered that rivers which have seen a decline or disappearance of anadromous lampreys, loss of the lampreys also affects the salmon in a negative way. Like salmon, anadromous lampreys stop feeding and die after spawning, and their decomposing bodies release nutrients into the stream. Also, along with species like rainbow trout and Sacramento sucker, lampreys clean the gravel in the rivers during spawning.[61] Their larvae, called ammocoetes, are filter feeders which contribute to the health of the waters. They are also a food source for the young salmon, and being fattier and oilier, it is assumed predators prefer them over salmon offspring, taking off some of the predation pressure on smolts. Adult lampreys are also the preferred prey of seals and sea lions, which can eat 30 lampreys to every salmon, allowing more adult salmon to enter the rivers to spawn without being eaten by the marine mammals. Sea lice, particularly Lepeophtheirus salmonis and various Caligus species, including C. clemensi and C. rogercresseyi, can cause deadly infestations of both farm-grown and wild salmon.[67][68] Sea lice are ectoparasites which feed on mucus, blood, and skin, and migrate and latch onto the skin of wild salmon during free-swimming, planktonic nauplii and copepodid larval stages, which can persist for several days. Large numbers of highly populated, open-net salmon farms[A] can create exceptionally large concentrations of sea lice; when exposed in river estuaries containing large numbers of open-net farms, many young wild salmon are infected, and do not survive as a result. On the Pacific coast of Canada, the louse-induced mortality of pink salmon in some regions is commonly over 80%. The risk of injury caused by underwater pile driving has been studied by Dr. Halvorsen and her co-workers.[76] The study concluded that the fish are at risk of injury if the cumulative sound exposure level exceeds 210 dB. ______ Recreational salmon fishing can be a technically demanding kind of sport fishing, not necessarily congenial for beginning fishermen.[77] A conflict exists between commercial fishermen and recreational fishermen for the right to salmon stock resources. Commercial fishing in estuaries and coastal areas is often restricted so enough salmon can return to their natal rivers where they can spawn and be available for sport fishing. On parts of the North American west coast sport salmon fishing completely replaces inshore commercial fishing.[78] In most cases, the commercial value of a salmon can be several times less than the value attributed to the same fish caught by a sport fisherman. This is "a powerful economic argument for allocating stock resources preferentially to sport fishing." Salmon are carnivorous. They are fed a meal produced from catching other wild fish and other marine organisms. Salmon farming leads to a high demand for wild forage fish. Salmon require large nutritional intakes of protein, and farmed salmon consume more fish than they generate as a final product. On a dry weight basis, 2-4 kg of wild-caught fish are needed to produce one kg of salmon.[79] As the salmon farming industry expands, it requires more wild forage fish for feed, at a time when 75% of the world's monitored fisheries are already near to or have exceeded their maximum sustainable yield.[80] The industrial-scale extraction of wild forage fish for salmon farming affects the survivability of the wild predator fish which rely on them for food. Work continues on substituting vegetable proteins for animal proteins in the salmon diet. This substitution results in lower levels of the highly valued omega-3 fatty acid content in the farmed product. Intensive salmon farming uses open-net cages, which have low production costs. It has the drawback of allowing disease and sea lice to spread to local wild salmon stocks.[81] Another form of salmon production, which is safer but less controllable, is to raise salmon in hatcheries until they are old enough to become independent. They are released into rivers in an attempt to increase the salmon population. This system is referred to as ranching. It was very common in countries such as Sweden, before the Norwegians developed salmon farming, but is seldom done by private companies. As anyone may catch the salmon when they return to spawn, a company is limited in benefiting financially from their investment. How could anyone possibly think this would work? There are limited resources... Because of this, the ranching method has mainly been used by various public authorities and nonprofit groups, such as the Cook Inlet Aquaculture Association, as a way to increase salmon populations in situations where they have declined due to overharvesting, construction of dams, and habitat destruction or fragmentation. Negative consequences to this sort of population manipulation include genetic "dilution" of the wild stocks. Many jurisdictions are now beginning to discourage supplemental fish planting in favour of harvest controls, and habitat improvement and protection. Farm-raised salmon are fed the carotenoids astaxanthin and canthaxanthin to match their flesh colour to wild salmon[82] to improve their marketability.[83] Wild salmon get these carotenoids, primarily astaxanthin, from eating shellfish and krill. One proposed alternative to the use of wild-caught fish as feed for the salmon, is the use of soy-based products. This should be better for the local environment of the fish farm, but producing soybeans has a high environmental cost for the producing region. The fish omega-3 fatty acid content would be reduced compared to fish-fed salmon. Another possible alternative is a yeast-based coproduct of bioethanol production, proteinaceous fermentation biomass. Substituting such products for engineered feed can result in equal (sometimes enhanced) growth in fish.[84] With its increasing availability, this would address the problems of rising costs for buying hatchery fish feed. Yet another attractive alternative is the increased use of seaweed. Seaweed provides essential minerals and vitamins for growing organisms. It offers the advantage of providing natural amounts of dietary fiber and having a lower glycemic load than grain-based fish meal.[84] In the best-case scenario, widespread use of seaweed could yield a future in aquaculture that eliminates the need for land, freshwater, or fertilizer to raise fish. Salmon is a popular food. Classified as an oily fish,[92] salmon is considered to be healthy due to the fish's high protein, high omega-3 fatty acids, and high vitamin D[93] content. Salmon is also a source of cholesterol, with a range of 23-214 mg/100 g depending on the species.[94] According to reports in the journal Science, farmed salmon may contain high levels of dioxins.[medical citation needed] PCB (polychlorinated biphenyl) levels may be up to eight times higher in farmed salmon than in wild salmon,[95] but still well below levels considered dangerous.[96][97] Nonetheless, according to a 2006 study published in the Journal of the American Medical Association, the benefits of eating even farmed salmon still outweigh any risks imposed by contaminants.[98] Farmed salmon has a high omega 3 fatty acid content comparable to wild salmon. Due to logging and development, much of the salmon's habitat (i.e., Ain River) has been destroyed, resulting in the fish being close to endangered.[103] For residents, this has resulted in limits on catches, in turn, has affected families diets, and cultural events such as feasts. Some of the salmon systems in danger include: the Davidon, Naden, Mamim, and Mathers.[103] It is clear that further protection is needed for salmon, such as their habitats, where logging commonly occurs. According to a recent Oceana report, "salmon farmers are using up to 950 grams of antibiotics to raise one ton of fish." The report also found that they might be applying more drugs per ton than any other fish industry in the world, twenty times more per ton than Norway. The reason for all these antibiotics is that the salmon are tightly confined in net pens filled to the brink with filth from fecal matter, uneaten food and chemical byproducts. According to a report by Universidad de Los Lagos, salmon farming generates discharges comparable to four times the number of human inhabitants in the area. The discharges are equivalent to the waste generated by a population of between 2.7 and 4.1 million people. Furthermore, the study indicates that, of all the feed supplied to the salmon, only around 25 percent is consumed. The other 75 percent remains in the environment. This food debris, in addition to fecal matter, produces an accumulation of phosphorus and nitrogen. Many farm pens are located near the mouths of rivers, where they contaminate other fish as they head downstream toward the ocean.

sea lice

Sea lice are marine ectoparasites (external parasites) that feed on the mucus, epidermal tissue, and blood of host marine fish. The genera Lepeophtheirus and Caligus parasitize marine fish, in particular those species that have been recorded on farmed salmon. The roughly 559 species in 37 genera include around 162 Lepeophtheirus and 268 Caligus species

silicon steel

Silicon steel is a soft magnetic material that is used in electrical power transformers, motors and generators. It has a high silicon content of about 3.2 mass %, which increases the electrical resistivity of iron and, therefore, reduces eddy current losses.

at what point does a species become a new species?

Speciation is the process by which new species form. It occurs when groups in a species become reproductively isolated and diverge. In allopatric speciation, groups from an ancestral population evolve into separate species due to a period of geographical separation.

Bluefin Tuna Population

Stocks of Pacific bluefin have fallen to 2.6 percent of their historic size, with countries like Mexico, Japan, Korea and the U.S. exceeding fishing quotas within the last two years. (2017) The groups agreed to establish sliding catch limits to reach that goal, based on how well the stocks recover in coming years, and have agreed to a harvest strategy timeline that includes stakeholder meetings over the next two years. The management groups have also committed to finding ways to prevent illegally caught bluefin tuna from reaching markets. There are currently 1.6 million Pacific bluefin in the Pacific, and of those, 145,000 are reproducing adults. "So while the numbers of bluefin tuna are much less than desirable, there are still a lot out there," says Yates.

How can supercooled water exist?

Supercooled water exists because it lacks the ability to complete the nucleation process. Two of the factors influencing the freezing of supercooled droplets are the need for a freezing nuclei (usually ice crystals) and latent heat which is released when water freezes.

could you see a supernova from another galaxy?

Supernova 1987A was visible to naked eye in southern hemisphere occurring in a nearby galaxy the Large Magellanic Cloud. Since the development of the telescope, the field of supernova discovery has expanded to other galaxies. These occurrences provide important information on the distances of galaxies.

Supersaturation

Supersaturation is a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances. It can also refer to a vapor of a compound that has a higher (partial) pressure than the vapor pressure of that compound.

Surface science

Surface science is the study of physical and chemical phenomena that occur at the interface of two phases, including solid-liquid interfaces, solid-gas interfaces, solid-vacuum interfaces, and liquid-gas interfaces. It includes the fields of surface chemistry and surface physics.[1] Some related practical applications are classed as surface engineering. The science encompasses concepts such as heterogeneous catalysis, semiconductor device fabrication, fuel cells, self-assembled monolayers, and adhesives. Surface science is closely related to interface and colloid science.[2] Interfacial chemistry and physics are common subjects for both. The methods are different. In addition, interface and colloid science studies macroscopic phenomena that occur in heterogeneous systems due to peculiarities of interfaces.

2002 Klamath River fish kill

The 2002 Klamath River fish kill occurred on the Klamath River in California in September 2002. According to the official estimate of mortality, about 34,000 fish died. Though some counts may estimate over 70,000 adult chinook salmon (Oncorhynchus tshawytscha) were killed when returning to the river to spawn,[1] making it the largest salmon kill in the history of the Western United States. A report by the U.S. Fish and Wildlife Service found that the kill resulted from water diversions to Klamath Basin by farmers and ranchers during a drought year.[3] The report found that the atypical low flow in the river along with high fish return numbers and high water temperatures allowed for a gill rot disease to kill at least 33,000 salmon in September 2002, before they could reproduce.

Hydrogen fusion

The Sun fuses four hydrogen nuclei to make one helium nucleus. Because one helium nucleus contains 0.7 percent less mass than four hydrogen nuclei, some mass vanishes in the process. In fact, that mass is converted to energy, and you could figure out how much by using Einstein's famous equation, E=mc^2 . For example, converting 1 kilogram (2.2 pounds) of matter completely into energy would produce an enormous amount of energy, 9 x 10^16 joules, comparable to the amount of energy a big city like Philadelphia uses in a year. Making one helium nucleus releases only a small amount of energy, hardly enough to raise a housefly one thousandth of an inch into the air. Only by concentrating many reactions in a small region can nature produce significant amounts of energy. The Sun has a voracious appetite and needs 10^38 reactions per second, transforming 4 million tons of mass into energy every second, just to replace the energy pouring into space from its surface. That might sound as if the Sun is losing mass at a furious rate, but in its entire 11-billion-year main-sequence lifetime, the Sun will convert only about 0.1 percent of its mass into energy Fusion reactions can occur only when the nuclei of two atoms get very close to each other. Because atomic nuclei carry positive charges, they repel each other with an electrostatic force called the Coulomb force. Physicists commonly refer to this repulsion between nuclei as the Coulomb barrier. To overcome this barrier, atomic nuclei must have violent collisions that are rare unless the gas is very hot, in which case the nuclei move at high speeds. (You recall that an object's temperature is just a measure of the average speed with which its particles move.) Thus nuclear reactions in the Sun take place only near the center, where the gas is hot and dense. A high temperature ensures that collisions between nuclei are violent enough to overcome the Coulomb barrier, and a high density ensures that there are enough collisions, and thus enough reactions, to produce enough energy to keep the Sun stable.

fish with antifreeze proteins

The antifreeze molecules allow icefish to live in subfreezing water by plugging gaps in existing small ice crystals and preventing the attachment of more ice molecules. Ice crystal growth is thus effectively stopped. To survive, Antarctic fishes have developed proteins that act as antifreeze. Antifreeze proteins (AFPs) or ice structuring proteins (ISPs) refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in subzero environments. AFPs bind to small ice crystals to inhibit the growth and recrystallization of ice that would otherwise be fatal.[3] There is also increasing evidence that AFPs interact with mammalian cell membranes to protect them from cold damage. This work suggests the involvement of AFPs in cold acclimatization. Unlike the widely used automotive antifreeze, ethylene glycol, AFPs do not lower freezing point in proportion to concentration.[citation needed] Rather, they work in a noncolligative manner. This phenomenon allows them to act as an antifreeze at concentrations 1/300th to 1/500th of those of other dissolved solutes. Their low concentration minimizes their effect on osmotic pressure.[4] The unusual properties of AFPs are attributed to their selective affinity for specific crystalline ice forms and the resulting blockade of the ice-nucleation process. ___________ Used to stop ice cream from melting. Edible antifreeze developed by a US researcher could keep ice cream tasty and smooth, and prevent other frozen foods from being ruined. The antifreeze contains proteins similar to those that help "snow flea" insects survive winter without freezing solid. He used a process called gel chromatography to separate the partly digested gelatine into proteins in different weight ranges. The gelatine samples were then added to different batches of identical ice cream frozen to -40 ºC. Damodaran studied the amino acid sequence of the most effective protein and found it was "strikingly similar" to that of a natural antifreeze found in snow fleas, a species of springtail that remains active throughout winter. There may be several commercial applications of these antifreeze proteins. These compounds are about 300 times more effective in preventing freezing than conventional chemical antifreezes at the same concentrations. The effectiveness of the fish antifreeze proteins in inhibiting ice growth suggests that they could be used to prevent freezing of food and freezing injury in several applications. For example, they could be used in the cryopreservation of foods that normally are rendered inedible due to ice crystal damage or to engineer cold resistance in living plants, as well as for the cryopreservation of tissues and organs. The study of the mechanism of how antifreezes bind to ice and inhibit its growth also provides insights into how other biomolecules affect growth of such pathogenic (harmful) bio-crystals as those associated with gout, kidney, and gall stones. Lastly, these proteins may have applications as non-polluting de-icing agents. To date, NSF-funded investigators have successfully introduced two of the four different types of fish antifreeze proteins into yeast and bacteria through recombinant DNA technology. Using these cloned genes and molecular technology, researchers can produce large quantities of antifreeze proteins through large-scale fermentation.

Will the worst bird flu outbreak in US history finally make us reconsider factory farming chicken?

The avian flu outbreak that has more than doubled egg prices across the country has also led to the death of more than 48 million birds in a dozen states, according to the US Department of Agriculture. Iowa, the hardest hit, has euthanized more than 31 million birds, including approximately 40% of the state's 60 million laying hens, according to Randy Olson, executive director of the Iowa Poultry Association. Turkey farmers in the state, while affected to a lesser degree, also have suffered. Minnesota, the leading turkey producer, has lost nearly 9 million turkeys. (2015) ______________ Currently, livestock operations burn through about 70 percent of the "medically important" antibiotics used in the nation—the ones people need when an infection strikes. Microbes that have evolved to withstand antibiotics now sicken 2 million Americans each year and kill 23,000 others—more than homicide. Even though public health authorities from the Food and Drug Administration and the Centers for Disease Control and Prevention have long pointed to the meat industry's reliance on antibiotics as a major culprit in human resistance to the drugs, the FDA has never reined in their use. And the worst part is that antibiotic use in factory farms isn't mostly a matter of keeping animals healthy. In 1950, a pharmaceutical company called American Cyanamid—now part of Pfizer—wanted to see if giving chickens vitamin B-12 made them fatter, so it ran some experiments. The idea seemed to work. But the researchers soon discovered it wasn't the vitamin that had fattened the birds; it was traces of an antibiotic called aureomycin. (B-12 can be a byproduct of aureomycin production; the vitamin researchers used had come from making the antibiotic.) This discovery revolutionized meat production. Adding a dash of antibiotics to feed and water rations magically made birds, pigs, and cows grow plumper, saving on feed costs and slashing the time it took to get animals to slaughter. In 1977, the General Accounting Office reported that "the use of antibiotics in animal feeds increased approximately sixfold" between 1960 and 1970. "Almost 100 percent of the chickens and turkeys, about 90 percent of the swine and veal calves, and about 60 percent of the cattle raised in the United States during 1970 received antibiotics in their feed."

carotid artery

The carotid arteries are major blood vessels in the neck that supply blood to the brain, neck, and face. There are two carotid arteries, one on the right and one on the left. In the neck, each carotid artery branches into two divisions: The internal carotid artery supplies blood to the brain.

mass-luminosity relation

The direct relationship between the masses and luminosities of main-sequence stars does not apply to stars not in the main sequence In fact, the mass-luminosity relation can be expressed as: Luminosity is proportional to mass to the 3.5 power. For example, a star with a mass of 4.0 M( can be expected to have a luminosity of about 4^3.5 or 128 L(. Giants, supergiants, and white dwarfs do not follow the mass-luminosity relation.

Deuterium fusion

The discovery of deuterium burning down to 0.012 solar masses and the impact of dust formation in the cool outer atmospheres of brown dwarfs in the late 1980s brought these theories into question. However, such objects were hard to find because they emit almost no visible light. Their strongest emissions are in the infrared (IR) spectrum, and ground-based IR detectors were too imprecise at that time to readily identify any brown dwarfs. Since then, numerous searches by various methods have sought these objects. These methods included multi-color imaging surveys around field stars, imaging surveys for faint companions of main-sequence dwarfs and white dwarfs, surveys of young star clusters, and radial velocity monitoring for close companions.

Interstellar Medium (ISM)

The gas and dust distributed between the stars. About 75 percent of the mass of interstellar gas is hydrogen, and 25 percent is helium; there are also traces of carbon, nitrogen, oxygen, calcium, sodium, and heavier atoms. Also, infrared light penetrates ISM dust better than shorter-wavelength radiation, so astronomers can use infrared cameras to look into and through interstellar clouds that are opaque to visible light. X-ray observations can detect regions of very hot gas apparently produced by exploding stars, like those in the constellation Cygnus (Figure 10-12b). Radio observations reveal the emissions of specific molecules in the interstellar medium—the equivalent of emission lines in visible light. Such studies show that some of the atoms in space have linked together to form molecules.

Kappa effect

The kappa effect or perceptual time dilation[1] is a temporal perceptual illusion that can arise when observers judge the elapsed time between sensory stimuli applied sequentially at different locations. In perceiving a sequence of consecutive stimuli, subjects tend to overestimate the elapsed time between two successive stimuli when the distance between the stimuli is sufficiently large, and to underestimate the elapsed time when the distance is sufficiently small.

Limbic System

The limbic system is a set of structures in the brain that deal with emotions and memory. It regulates autonomic or endocrine function in response to emotional stimuli and also is involved in reinforcing behavior .

zero-age main sequence (ZAMS)

The location in the H-R diagram where stars first reach stability as hydrogen-burning stars Recall that hydrogen fusion combines four nuclei into one. As a main-sequence star fuses its hydrogen, the total number of particles in its interior decreases. Each newly made helium nucleus can exert only the same pressure as a hydrogen nucleus. Because the gas has fewer nuclei, its total pressure is less. This unbalances the gravity-pressure stability, and gravity squeezes the core of the star more tightly. As the core contracts, its temperature increases and the nuclear reactions run faster, releasing more energy. This additional energy flowing outward forces the outer layers to expand. Therefore, as a main-sequence star slowly turns hydrogen into helium in its core, the core contracts and heats up while the outer parts of the star become larger, the star becomes more luminous, and its surface cools down. These gradual changes during the lifetimes of main-sequence stars mean that the main sequence is not a sharp line across the H-R diagram, but rather a band. Stars begin their stable lives fusing hydrogen on the lower edge of this band, which is known as the zero-age main sequence (ZAMS), but gradual changes in luminosity and surface temperature move the stars upward and slightly to the right, as shown in Figure 10-8. By the time they reach the upper edge of the main sequence, they have exhausted nearly all the hydrogen in their centers. If you precisely measure and plot the luminosity and temperature of main-sequence stars on the H-R diagram, you will find them at various positions within the main-sequence band, indicating how much hydrogen has been converted to helium in their cores. Therefore, you can use the position of a star in the band, combined with stellar evolution models, as one way to estimate the star's age. The Sun is a typical main-sequence star; and, as it undergoes these gradual changes, Earth will suffer. When the Sun began its main-sequence life about 5 billion years ago, it was only about 70 percent as luminous as it is now, and by the time it leaves the main sequence in another 6 billion years, the Sun will have twice its present luminosity. Long before that, the rising luminosity of the Sun will raise Earth's average temperature, melt the polar caps, modify Earth's climate, and ultimately boil away and destroy Earth's oceans. Life on Earth will probably not survive these changes in the Sun, but humans have a billion years or more to prepare. The average star spends 90 percent of its life on the main sequence. This explains why 90 percent of all true stars (stars powered by nuclear fusion) are main-sequence stars—you are most likely to see a star during that long, stable period while it is on the main sequence. The amount of time a star spends on the main sequence depends on its mass (Table 10-2). Massive stars consume fuel rapidly and live short lives, but low-mass stars conserve their fuel and shine for billions of years. For example, a 25-solar-mass star will exhaust its hydrogen and die in only about 4 million years. The Sun has enough fuel to last about 11 billion years. The red dwarfs, although they have little fuel, use it up very slowly and may be able to survive for 100 billion years or more.

brown dwarf

The mass-luminosity relation also tells you why the main sequence has a lower end, a minimum mass. Objects with masses less than about 0.08 of the Sun's mass cannot raise their central temperature high enough to sustain hydrogen fusion. These are called brown dwarfs, and may still be warm from the processes of formation, but they do not generate energy by hydrogen fusion. They have contracted as much as they can and are slowly cooling off. Comparison: most brown dwarfs are only slightly larger than Jupiter (10-15%) but up to 80 times more massive due to greater density. Image is approximately to scale, with Jupiter's radius 10 times that of Earth, and the Sun's radius 10 times that of Jupiter. Brown dwarfs fall in the gap between low-mass M stars and massive planets like Jupiter. They would look dull orange or red to your eyes—which is why they are labeled "brown"—because they emit most of their energy in the infrared. The warmer brown dwarfs fall in spectral class L and the cooler in spectral class T (look back to Chapter 9 Section 9-3a). Because they are so small and cool, brown dwarfs are very low-luminous objects and thus are difficult to find. Nevertheless, hundreds are known, and they may be as common as M stars.

spectroscopic parallax

The method of determining a star's distance by comparing its apparent magnitude with its absolute magnitude, as estimated from its spectrum.

The p-p II branch

The p-p II branch is dominant at temperatures of 14 to 23 MK. Note that the energies in the equation above are not the energy released by the reaction. Rather, they are the energies of the neutrinos that are produced by the reaction. 90 percent of the neutrinos produced in the reaction of 7Be to 7Li carry an energy of 0.861 MeV, while the remaining 10 percent carry 0.383 MeV. The difference is whether the lithium-7 produced is in the ground state or an excited (metastable) state, respectively.

The p-p III branch

The p-p III chain is dominant if the temperature exceeds 23 MK. The p-p III chain is not a major source of energy in the Sun (only 0.11 percent), but it was very important in the solar neutrino problem because it generates very high energy neutrinos (up to 14.06 MeV).

proton-proton chain

The proton-proton chain is a series of three nuclear reactions that build a helium nucleus by adding protons one at a time. This process is efficient at temperatures above 10,000,000 K. The Sun's energy is created this way. Recall from the previous section that models of the interior of the Sun based on its overall stability indicate the central temperature is about 16,000,000 K. In the first reaction, two hydrogen nuclei (two protons) combine, and one changes into a neutron, to result in a heavy hydrogen nucleus called deuterium, while emitting a particle called a positron (a positively charged electron, symbolized by e⁺) and another called a neutrino (v). In the second reaction, the heavy hydrogen nucleus absorbs another proton and, with the emission of a gamma-ray (γ), becomes a lightweight helium nucleus (He3). Finally, two light helium nuclei combine to form a normal helium nucleus and two hydrogen nuclei. Because the last reaction needs two He3 nuclei, the first and second reactions must occur twice for each He4 to be produced, as shown in Figure 10-6. The net result of this chain reaction is the transformation of four hydrogen nuclei into one helium nucleus plus energy All main-sequence stars fuse hydrogen into helium to generate energy. The Sun and smaller stars fuse hydrogen by the proton-proton chain. Upper-main-sequence stars, more massive than the Sun, fuse hydrogen by a more efficient process called the CNO (carbon-nitrogen-oxygen) cycle.

Compton scattering

The scattering of a photon by a charged particle, usually an electron. It results in a decrease in energy (increase in wavelength) of the photon (which may be an X-ray or gamma ray photon), called the Compton effect. Energy transfer from a photon to an electron or other charged particle.

The residual strong force is effective over a very short range (usually only a few femtometres (fm); roughly one or two nucleon diameters) and causes an attraction between any pair of nucleons. For example, between protons and neutrons to form [NP] deuteron, and also between protons and protons, and neutrons and neutrons.

The strong force starts off highly repulsive, but becomes attractive after 1.3 fm and shortly after falls off to zero.

luminosity

The total amount of energy emitted by a star, galaxy, or other astronomical object, in all wavelengths, per unit time. With the absolute magnitudes of the stars in hand, you can now compare stars using our Sun as a standard. The intrinsically brightest stars have absolute magnitudes of about −8.3. If such a star were 10 pc away from Earth, it would be more than 25 times as bright as Venus at its brightest. Such stars emit more than 100,000 times as much light at visual wavelengths than the Sun

protein therapeutics

Therapeutic proteins are proteins that are engineered in the laboratory for pharmaceutical use, including noncovalent binders, proteins that affect covalent bonds which are almost all enzymes, and albumin. Therapeutic proteins are highly effective in vivo and have revolutionized treatment of diseases.

VY Canis Majoris

This red hypergiant is among the largest known stars in our galaxy. It has an estimated radius between 1,800 and 2,100 times that of the Sun. At this size, if placed in our solar system, it would reach nearly to the orbit of Saturn 1.2277 billion mile diameter That's 3 quadrillion 729 trillion Earths that fit into the volume of VY Canis Majoris. Because of their high masses, the lifetime of a hypergiant is very short in astronomical timescales: only a few million years compared to around 10 billion years for stars like the Sun. Astronomers think that this star is at the end of its life, and will explode as a hypernova in the relatively near future. Situated in the constellation Canis Major, about 3,900 light years from earth, this star is the largest hypergiant we know of. This stellar titan was first observed over 200 years ago, and for many years afterwards it was suspected that it was part of a binary system. Because VY CMa is similar to what are known as Wolf-Rayet stars, it is surrounded by a large nebulae of complex arcs and filaments, meaning it was difficult for Astronomers to view the star effectively through the interstellar gas and dust clouds. After extensive studies were undertaken by the Hubble Space Telescope, it was confirmed in 1998 that there is no companion star. It takes over 8 HOURS for photons to travel from one side of the star to the other. Hypergiants like VY Canis Majoris are so massive that they devour themselves at exponential rates. The amount of energy our Sun emits in year is equal to what a hypergiant would release in the matter of just 6 seconds. Although, these enormous levels of activity means that their lives are only measurable in *millions* of years (by comparison, our Sun is a pretty 'normal' star, and will live for about 10 *billion* years). But as well as burning up their fuel quickly, they also throw out billions of tons of gas and matter in violent explosions and outbursts - this further shortens the life of the star. It is believed that VY Canis Majoris has already shed half of its original mass, and could literally reach hypernovae at any time, but some astronomers believe that the star has the capability to last nearly another 100,000 years. Hypernovae are a rare form of supernova, producing enough energy that they easily equal 100 regular supernovae. The core collapse of the star is so fast that the gamma rays produced can decompose the nuclei of elements such as iron inside the star. As neutrinos escape, the process is accelerated and protons and electrons are squeezed together to produce more neutrons and neutrinos - because the core now consists of almost no electrons, the neutrons/nuclei can pack together closer and closer until they can go no tighter. In a regular supernova this extremely dense ball could become a neutron star or a pulsar, but the unusually high mass of VY Canis Majoris (or a similar hypergiant) would result in the formation of a rogue stellar-mass black hole... with an explosion of gamma rays that has the ability to wipe out any cellular life in nearby solar systems. Luckily for us, we aren't at risk from these rare and deadly objects. In fact, there are only a little more than 10 hypergiants recorded out of the 100 billion other stars present in the Milky way. On the positive side, the explosion of a hypergiant has the potential to condense clouds and increase proto-star formation within nearby nebulae or dust clouds. The spectacle would also shine so brightly that we would be able to see it during daytime here on earth! In an average sized galaxy a supernova occurs about every 50 years, and this means many have been recorded by our early and late ancestors. The last of which, was recorded by the famed astronomer, Johannes Kepler in 1604.

pervert

To pervert something is to corrupt it. For example, you could "pervert the course of justice" by lying on the witness stand.

molecular clouds

To study the formation of stars, you can continue comparing hypothesis with evidence. The theory of gravity predicts that the combined gravitational attraction of the atoms in a cloud of gas will shrink the cloud, pulling every atom toward the center. That might lead you to expect that every cloud would eventually collapse and become a star; however, the thermal energy in the cloud resists collapse. Interstellar clouds are very cold; but, even at a temperature of only 10 K, the average particle moves at about 0.33 km/s (740 mph). That much thermal motion would make the cloud drift apart if gravity were too weak to hold it together. Other factors can help a cloud resist its own gravity. Observations show that clouds are turbulent with currents of gas pushing through and colliding with each other. Also, magnetic fields in clouds may resist being squeezed. The thermal motion of the atoms, turbulence in a cloud, and magnetic fields resist gravity, and only the densest clouds are likely to contract. The densest interstellar clouds contain from 10^3 to 10^5 atoms/cm3 and have temperatures as low as 10 K. They include a few hundred thousand to a few million solar masses. In such dense clouds, hydrogen can exist as molecules (H2) rather than as atoms. These very densest parts of the ISM are called molecular clouds, and the largest are called giant molecular clouds. Although hydrogen molecules cannot be detected by radio telescopes, the clouds can be mapped by the emission lines of carbon monoxide molecules (CO) present in small amounts in the gas. By now you may have realized the main point: Stars can form inside molecular clouds when the densest parts of the clouds become unstable and contract under the influence of their own gravity. Most clouds do not appear to be gravitationally unstable and will not contract to form stars on their own. However, a stable cloud colliding with a shock wave (the astronomical equivalent of a sonic boom) can be compressed and disrupted into fragments. Theoretical calculations show that some of these fragments can become dense enough to collapse under the influence of their own gravity and form stars, as shown in Figure 10-13.

Transcriptomics technologies

Transcriptomics technologies are the techniques used to study an organism's transcriptome, the sum of all of its RNA transcripts. The information content of an organism is recorded in the DNA of its genome and expressed through transcription. Here, mRNA serves as a transient intermediary molecule in the information network, whilst non-coding RNAs perform additional diverse functions. A transcriptome captures a snapshot in time of the total transcripts present in a cell. Transcriptomics technologies provide a broad account of which cellular processes are active and which are dormant. A major challenge in molecular biology lies in understanding how the same genome can give rise to different cell types and how gene expression is regulated.

Regenerative medicine

Using stem cells to repair damaged tissue that cannot repair itself Regenerative medicine is a branch of translational research[1] in tissue engineering and molecular biology which deals with the "process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function".[2] This field holds the promise of engineering damaged tissues and organs by stimulating the body's own repair mechanisms to functionally heal previously irreparable tissues or organs.[3] Regenerative medicine also includes the possibility of growing tissues and organs in the laboratory and implanting them when the body cannot heal itself. If a regenerated organ's cells would be derived from the patient's own tissue or cells,[4] this would potentially solve the problem of the shortage of organs available for donation, and the problem of organ transplant rejection.[5][6][7]

A third mass coral bleaching event in five years is recorded at the Great Barrier Reef.

Warmer sea temperatures - particularly in February - are feared to have caused huge coral loss across the world's largest reef system. Scientists say they have detected widespread bleaching, including extensive patches of severe damage. But they have also found healthy pockets. Two-thirds of the reef was damaged by similar events in 2016 and 2017. The reef system, which covers over 2,300km (1,400 miles), is a World Heritage site recognised for its "enormous scientific and intrinsic importance". Last year, Australia was forced to downgrade its five-year reef outlook from poor to very poor due to the impact of human-induced climate change. Global temperatures have already risen about 1C since pre-industrial times. The UN has warned that if temperatures rise by 1.5C, 90% of the world's corals will be wiped out.

Mitosis Vs. Meiosis

We have mentioned two types of nuclear division: mitosis, where the nucleus divides into two identical nuclei, and meiosis, which results in the production of four nuclei with half the original number of chromosomes of the parent cell. We will go through all the detailed steps of mitosis and meiosis in the next section, but first let's focus on how the processes have some features in common, yet are still different. In order to understand these two processes, it is important to become familiar with the terms diploid and haploid. A diploid cell has two of each chromosome, one from each parent. This is in contrast to a haploid cell, which only has one copy of every chromosome. Diploid cells comprise the majority of your body, while examples of haploid cells are eggs and sperm. If a haploid cell has n chromosomes, a diploid cell has 2n (n represents a number, which is different for every species - in humans, for example, n = 23 and 2n = 46). Both diploid and haploid cells can undergo mitosis. This makes a lot of sense, because mitosis is essentially like making a photocopy: it creates a perfect reproduction of what you started with. Therefore, if a diploid cell undergoes mitosis, the result is two identical diploid cells (2n →2n). Prokaryotic cells, for example bacteria, use this process to reproduce asexually, in a process known as binary fission. If a haploid cell undergoes mitosis, which is something certain types of plant and fungus do as part of their normal life cycles, the end result is two identical haploid cells (n→n). In meiosis, however, you start with a diploid cell that divides twice to produce four haploid cells. In other words a diploid cell that has 2n chromosomes produces four cells, each of which contains n chromosomes. Now let's step back and talk briefly about chromosomes. Most of the time, each chromosome is a single, long molecule of DNA. But, a chromosome isn't DNA; it also contains proteins, called histones, which the DNA is wrapped around for protection and support. Except in bacteria—their DNA is completely naked. And by naked, we mean doesn't have any histones. Sorry. Together, the DNA and proteins are known as chromatin, which translates roughly as "colored stuff"; in fact, the word chromosome literally means "colored body." Every eukaryotic organism has its own particular number of chromosomes of a particular shape and size. This is known as its karyotype. Cytogenetics is the study of karyotypes and is a important tool when studying human chromosomal abnormalities and diagnostically in prenatal screening. Now we've mentioned that a haploid cell has n chromosomes, while a diploid cell has 2n chromosomes. To recap, a diploid cell has two copies of each type of chromosome. These two copies are not exactly the same, though; one is from Mom and one is from Dad. These two chromosomes, one from each parent, are known as homologous chromosomes (or a homologous pair). They carry the same type of information (that is, the various genes on that chromosome), but they are not identical because each will have slightly different DNA sequences by which you can tell them apart. Humans have 23 homologous pairs of chromosomes: 22 pairs of autosomes and 1 "pair" of sex chromosomes. Technically, if you are a girl it is an actual pair (XX), but if you are a boy, they are different (XY). We will ignore the sex chromosome differences for now, because we are all about keeping it nice and simple. In mitosis, as we've said, the cell has chromosomes with 2 identical halves, the sister chromatids. The cell must ensure that when it divides into two, each cell gets only one of those sisters. Let's go back to our hot chocolate analogy: two customers, our daughter cells, order two hot chocolates each, they must be thirsty, one with whipped cream, representing Mom's chromosome, and one without, representing Dad's. The barista is efficient and decides to make both cups of the whipped cream hot chocolate at the same time. He puts the two cream ones on the counter next to each other and then does the same with the plain ones. He then checks the orders, putting one of each type of hot chocolate onto two separate trays, ready for each customer to take away. The cell uses this strategy too. Right after DNA replication, the two sister chromatids are held together by a group of proteins that act as a type of glue. When it is time to separate the chromatids the glue is dissolved and voila. Accurate chromosome segregation. How does the cell orchestrate the separation of chromosomes in this case? Let's return to our hot chocolate (yum). In our mitosis example above, all we cared about was that we separated our drinks, or chromatids, such that each customer, daughter cell, got one drink of each kind. One homologue, or the version of the drink with whipped cream is treated the same as the other, or the version of the drink without cream. But, meiosis is more complicated because we need to be able to keep track of all four chromatids individually. Let's say we have two customers again, the ones who are paying, if you like, but now they have brought their two friends along as well. One pair wants hot chocolate with whipped cream, the other pair is trying to be good, so no cream for them. Our barista is still efficient and makes the two whipped cream versions together, then the two plain ones. This time when he checks the orders, he puts both of creamy ones on one tray for one customer to take away, or the first meiotic division, before she gives one to her friend, or the second meiotic division. The same happens for the plain hot chocolates. The cell has special linkages called chiasmata that connect homologous chromosomes together during the earliest stage of meiosis (prophase I). During the first division, these linkages are dissolved and the two identical chromatids from Mom, or the two hot chocolates with whipped cream, and the two identical chromatids from Dad, or the two hot chocolates without whipped cream, are separated, or put on separate trays. In the next division, one of each of the sister chromatids, or identical drinks, makes it into a separate cell using effectively the same mechanism as in mitosis. _________ We have mostly talked about the celebrities of division, the chromosomes. But it turns out that chromosomes are not any different from puppets on a string. Without the string the puppets can't move, even though they are the stars of the show. In mitosis and meiosis, the string is the spindle, and without the spindle the chromosomes aren't going anywhere. What is the mitotic spindle? The spindle itself comprises microtubules, which are organized in animal cells by special structures called centrosomes. When it's time for the cell to divide, the two centrosomes in the cell move around the nucleus such that they are on opposite sides. Only one centrosome makes it into each daughter cell at the end of cell division, so the cell needs to create a new centrosome each cell cycle. In meiosis, a similar spindle forms during each meiotic division to orchestrate the movement of the chromosomes.

Goodhart's law

When a measure becomes a target, it ceases to be a good measure "Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes." Goodhart's law is an adage named after economist Charles Goodhart, which has been phrased by Marilyn Strathern as "When a measure becomes a target, it ceases to be a good measure." One way in which this can occur is individuals trying to anticipate the effect of a policy and then taking actions that alter its outcome.

Cell division

When scientists talk about a cell's life, they often use familial terms. For example, a chromosome that has undergone DNA replication has an exact copy of itself. We call this exact copy a sister chromatid. When a cell undergoes division to create two new identical cells, we call them daughter cells. Cell division is also called cellular reproduction. The eukaryotic cell cycle can be visually characterized into two phases, called M phase and interphase. If you looked at rapidly dividing cells from your body under the microscope, few cells would be physically separating their genetic material. That's because the actual division phase (M phase) takes only about 30-60 minutes. During M phase, in a series of dramatic events, the duplicated chromatids condense and become visible under a light microscope. They are then segregated to opposite poles of the cell, and the cell is pinched into two separate cells. We refer to mitosis as the division of the nuclear DNA, while cytokinesis refers to the process by which the cytoplasm is divided into two daughter cells. The rest of the time the cell is in interphase, and depending on the situation, interphase can last for days, weeks, or even longer. Weirdly, interphase is often called a resting phase which, as we will see, is anything but the truth. M phase may get all the attention because it is dramatic (remind you of anyone you know?), but most of the preparations for division occur during interphase. And in cell division, as in life, preparation is everything. What is interphase really? Interphase can be broken into three phases: G1, S, and G2. During G1 phase, or gap 1, cells grow, do their job, replicate their organelles, and produce the proteins needed for DNA replication and chromosome segregation. S phase, or synthesis phase, is when the cell replicates its DNA. In a typical human cell, S phase takes up almost half of the time of the cell cycle; therefore, S phase often takes about 10-12 hours. G2 phase, or gap 2, follows S phase. The cell uses this gap period to continue to grow and carry out its normal functions, replicate its organelles, and produce the proteins required for cell division. What controls the cell going from one phase to another? Eukaryotic cells have evolved a complex regulatory system that involves a large network of proteins. These proteins control the main events of the cell cycle, namely DNA replication and the segregation of the identical chromatids to opposite sides of the cell. It is helpful to think of these proteins as a sort of biochemical traffic-light system, giving the cell either the red or green light. The gap phases are important for coordinating this regulation, and it is during this time that the cell senses its environment and can make decisions about whether or not to proceed. This system is crucial because it helps ensure that all the events happen when they should—for example, by preventing the segregation of the chromatids until after DNA replication has finished. That'd be like baking chocolate chip cookies before adding the chocolate chips and sugar—yuck. What happens if the regulation fails? Such a failure can lead to cell death or even cancer. We will talk more about that when we come to regulation. Sometimes the cell exits from the cell cycle into special phases. One such phase is G0, sometimes called the quiescent phase, which is considered a resting phase the cells go into once they have stopped dividing. But again, it isn't exactly sitting around with its feet up, doing nothing. The cell is still carrying out its normal functions. Other times, the cell enters into a specialized phase of division called meiosis, so it can produce gametes for sexual reproduction. In meiosis the number of chromosomes in a parent cell is reduced by half. Meiosis occurs in two successive division stages, meiosis I and meiosis II, which we will cover in more detail later. Exactly when cells go into meiosis will differ, depending on whether you are male or female. Soda and the cell cycle? Sure, we all consume drinks with caffeine. However, did you know that caffeine is a commonly used tool by scientists studying the cell cycle? When caffeine is introduced to a cell stalled in its cell cycle because its DNA is damaged, the cell ignores its regulatory system and continues dividing. And you thought that caffeine was only good for keeping you awake. Another chemical used to study the cell cycle (and diagnostically in the field of cytogenetics) is colchicine. It stops the mitotic spindle from forming properly, arresting the cell cycle in metaphase. Where does colchicine come from? The autumn crocus. It's not so much "don't eat the daisies" as just "don't eat any crocus bulbs" if you want your cells to keep dividing.

When Yellow Warblers Warn of Brood Parasites, Red-winged Blackbirds Listen

While the Yellow Warbler is best known for its cheery song, the birds also produce a seet call that many birders might recognize. Research has shown that these calls are distinct from the bird's alarm call for predators such as Blue Jays, which prey on their eggs, and are specifically meant to warn against Brown-headed Cowbirds, brood parasites that often target Yellow Warbler nests. When a female hears the call, she rushes back to the nest to prevent the cowbird from laying an egg. Now, according to research published last month in Communications Biology, it turns out another species might also benefit from these seet calls: Red-winged Blackbirds who nest near Yellow Warblers. "We've known about the seet call of the Yellow Warbler," says Mark Hauber, a behavioral ecologist at the University of Illinois at Urbana-Champaign and co-author of the study. "What we didn't know was that another species understands the seet call and considers it to be a danger to itself, too." Although cowbirds trick more than 200 bird species into raising their young, only Yellow Warblers produce a specific warning call that signals a cowbird's presence. And though research has shown that several species, including nuthatches and hornbills, eavesdrop on their neighbors' conversations to gather intel on predators or good feeding spots, this is the first report of one species recognizing another's brood parasite warning. This ability might help Red-wingeds in their own defenses against cowbirds, the researchers say.

can we see stars in other galaxies with telescopes?

Yes. Andromeda is 2.5 million light years away. The Hubble Space Telescope easily resolves millions of individual stars in an outer region of the Andromeda Galaxy, also known as M31.

Is meat the same as muscle?

Yes. Technically, every part of the "animal" is edible. Many have described human as tasting like pork. Current imprisoned cannibals have likened it to veal. What makes muscle turn to "meat" is when the animal dies or is slaughtered, blood ceases to circulate through the muscle, since there is no oxygen sugars break down and lactic acid builds up. Since there is nothing regenerating, the muscle locks up in what we call rigor mortis. As proteins break down the meat becomes tender. All muscle is meat. There are also organ meats, like kidneys, liver, heart, tongue, gizzards, brains, etc. Though heart and tongue are usually also considered muscle. For that matter, fat is often considered meat, too. Especially if you're a vegetarian. It's tough to be precise when you're trying to apply anatomical and biological terms to the culinary world. Sort of like how a tomato is botanically a fruit, but you don't put tomatoes in fruit salad. Science and cooking are two different human pursuits with two different vocabularies, which only match up approximately. _______________ Meat is mainly composed of water, protein, and fat. It is edible raw, but is normally eaten after it has been cooked and seasoned or processed in a variety of ways. Unprocessed meat will spoil or rot within hours or days as a result of infection with and decomposition by bacteria and fungi. Adult mammalian muscle flesh consists of roughly 75 percent water, 19 percent protein, 2.5 percent intramuscular fat, 1.2 percent carbohydrates and 2.3 percent other soluble non-protein substances. These include nitrogenous compounds, such as amino acids, and inorganic substances such as minerals.[1]:76 Muscle proteins are either soluble in water (sarcoplasmic proteins, about 11.5 percent of total muscle mass) or in concentrated salt solutions (myofibrillar proteins, about 5.5 percent of mass).[1]:75 There are several hundred sarcoplasmic proteins.[1]:77 Most of them - the glycolytic enzymes - are involved in the glycolytic pathway, i.e., the conversion of stored energy into muscle power.[1]:78 The two most abundant myofibrillar proteins, myosin and actin,[1]:79 are responsible for the muscle's overall structure. The remaining protein mass consists of connective tissue (collagen and elastin) as well as organelle tissue.[1]:79 Fat in meat can be either adipose tissue, used by the animal to store energy and consisting of "true fats" (esters of glycerol with fatty acids),[1]:82 or intramuscular fat, which contains considerable quantities of phospholipids and of unsaponifiable constituents such as cholesterol.[1]:82 Meat can be broadly classified as "red" or "white" depending on the concentration of myoglobin in muscle fibre. When myoglobin is exposed to oxygen, reddish oxymyoglobin develops, making myoglobin-rich meat appear red. The redness of meat depends on species, animal age, and fibre type: Red meat contains more narrow muscle fibres that tend to operate over long periods without rest,[1]:93 while white meat contains more broad fibres that tend to work in short fast bursts.[1]:93 Draining as much blood as possible from the carcass is necessary because blood causes the meat to have an unappealing appearance and is a breeding ground for microorganisms. The exsanguination is accomplished by severing the carotid artery and the jugular vein in cattle and sheep, and the anterior vena cava in pigs. Additionally, slaughterhouse workers are exposed to noise of between 76 and 100 dB from the screams of animals being killed. 80 dB is the threshold at which the wearing of ear protection is recommended. During the first day after death, glycolysis continues until the accumulation of lactic acid causes the pH to reach about 5.5. The remaining glycogen, about 18 g per kg, is believed to increase the water-holding capacity and tenderness of the flesh when cooked.[1]:87 Rigor mortis sets in a few hours after death as ATP is used up, causing actin and myosin to combine into rigid actomyosin and lowering the meat's water-holding capacity,[1]:90 causing it to lose water ("weep").[1]:146 In muscles that enter rigor in a contracted position, actin and myosin filaments overlap and cross-bond, resulting in meat that is tough on cooking[1]:144 - hence again the need to prevent pre-slaughter stress in the animal. Over time, the muscle proteins denature in varying degree, with the exception of the collagen and elastin of connective tissue,[1]:142 and rigor mortis resolves. Because of these changes, the meat is tender and pliable when cooked just after death or after the resolution of rigor, but tough when cooked during rigor.[1]:142 As the muscle pigment myoglobin denatures, its iron oxidates, which may cause a brown discoloration near the surface of the meat.[1]:146 Ongoing proteolysis also contributes to conditioning. Hypoxanthine, a breakdown product of ATP, contributes to the meat's flavor and odor, as do other products of the decomposition of muscle fat and protein.[1]:155

shock wave

a cone shaped wave produced by an object moving at supersonic speed through a fluid Supernova explosions produce shock waves that compress the interstellar medium, and recent observations show young stars forming at the edges of such shock waves. Another source of shock waves may be the birth of very hot stars. A massive star is so luminous and hot that it emits vast amounts of ultraviolet photons. When such a star is born, the sudden blast of light, especially ultraviolet radiation, can ionize and drive away nearby gas, forming a shock wave that could compress nearby clouds and trigger further star formation. Even the collision of two interstellar clouds can produce a shock wave and trigger star formation. Some of these processes are shown in Figure 10-14. Most clouds do not appear to be gravitationally unstable and will not contract to form stars on their own. However, a stable cloud colliding with a shock wave (the astronomical equivalent of a sonic boom) can be compressed and disrupted into fragments. Theoretical calculations show that some of these fragments can become dense enough to collapse under the influence of their own gravity and form stars, as shown in Figure 10-13. Although these are important sources of shock waves, the dominant trigger of star formation in our Galaxy may be the spiral pattern itself. In Chapter 1, you learned that our Galaxy contains spiral arms. As interstellar clouds encounter these spiral arms, the clouds are compressed, and star formation can be triggered (see Chapter 12). Once begun, star formation can spread like a grass fire. Both high-mass and low-mass stars form together, but when the massive stars form, their intense radiation or eventual supernova explosions push back the surrounding gas and compress it. This compression in turn can trigger the formation of more stars, some of which will be massive. Thus, a few massive stars can drive a continuing cycle of star formation in a giant molecular cloud.

euphemism

a mild or indirect word or expression substituted for one considered to be too harsh or blunt when referring to something unpleasant or embarrassing. For example, "kick the bucket" is a euphemism that describes the death of a person.

zinger

a quick and witty comment that criticizes or insults someone

Keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically. Because of their role in transporting nutrients from the ocean to river and riparian ecosystems, Pacific salmon (Oncorhynchus spp.) and brown bear (Ursus arctos) have been described as keystone species and mobile links, although few data are available to quantify the importance of this interaction relative to other nutrient vectors. The jaguar, a keystone, flagship, and umbrella species, and an apex predator Ecological theory holds that certain animals exert a disproportionately important influence on the ecosystems in which they live. Paine (1966) first described this phenomenon in reporting how a predatory starfish (Pisaster ochraceus) influences the species composition and population density of an intertidal ecosystem. By eating masses of barnacles, Pisaster prevents competitive exclusion by dominant organisms, thereby creating open space for a greater number of species. Paine (1969) subsequently introduced the term ''keystone species'' to describe those animals that control the integrity and stability of their communities.

Binary stars

a system of two stars in which one star revolves around the other or both revolve around a common center. more than half of all stars are binary stars Exoplanets are possible in binary star systems. In fact, they are possible in trinary star systems. Proxima Centauri b is an exoplanet orbiting in the habitable zone of the red dwarf star Proxima Centauri, which is the closest star to the Sun and part of a triple star system.

stellar model

a table of numbers representing the conditions in various layers within a star R/R = Radius M/M = Mass L/L = Luminosity

Theory of mind

ability to reason about what other people know or believe Theory of mind is the ability to attribute mental states — beliefs, intents, desires, emotions, knowledge, etc. — to oneself and to others. Theory of mind is necessary to understand that others have beliefs, desires, intentions, and perspectives that are different from one's own.

Biomagnification

accumulation of pollutants at successive levels of the food chain Biological magnification often refers to the process whereby certain substances such as pesticides or heavy metals work their way into lakes, rivers and the ocean, and then move up the food chain in progressively greater concentrations as they are incorporated into the diet of aquatic organisms such as zooplankton, which in turn are eaten perhaps by fish, which then may be eaten by bigger fish, large birds, animals, or humans. The substances become increasingly concentrated in tissues or internal organs as they move up the chain. Bioaccumulants are substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted.

Transcriptome

all the RNA molecules transcribed from a genome The transcriptome is the set of all RNA molecules in one cell or a population of cells. It is sometimes used to refer to all RNAs, or just mRNA, depending on the particular experiment. It differs from the exome in that it includes only those RNA molecules found in a specified cell population, and usually includes the amount or concentration of each RNA molecule in addition to the molecular identities. It differs from the translatome, which is the set of RNAs undergoing translation.

supergiant

an extremely bright star of very large diameter and low density Exceptionally luminous star whose diameter is 100 to 1000 times that of the Sun

Overfishing

capturing fish faster than they can reproduce Overfishing is the removal of a species of fish from a body of water at a rate that the species cannot replenish in time, resulting in those species either becoming depleted or very underpopulated in that given area. If fishing rates continue unchanged, all the world's fisheries will have collapsed by the year 2048.

Mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Interspecific competition

competition between members of different species

luminosity classes

different groupings into which stars can be placed based upon the differing widths of their spectral lines The luminosity classes are represented by the Roman numerals I through V, with supergiants further subdivided into types Ia and Ib. For example, you can distinguish between a luminous supergiant (Ia) such as Rigel (Beta Orionis) and a regular supergiant (Ib) such as Polaris, the North Star (Alpha Ursa Minoris). The star Adhara (Epsilon Canis Majoris) is a luminous giant (II), Aldebaran (Alpha Tauri) is a giant (III), and Altair (Alpha Aquilae) is a subgiant (IV). The Sun is a main-sequence star (V). The luminosity class notation appears after the spectral type, as in G2 V for the Sun. White dwarfs don't enter into this classification because their spectra are very different from the other types of stars.

rhabdomyolysis

dissolution of striated muscle (caused by trauma, extreme exertion, or drug toxicity; in severe cases renal failure can result) A breakdown of muscle tissue that releases a damaging protein into the blood. This muscle tissue breakdown results in the release of a protein (myoglobin) into the blood. Myoglobin can damage the kidneys. Symptoms include dark, reddish urine, a decreased amount of urine, weakness, and muscle aches. Early treatment with aggressive fluid replacement reduces the risk of kidney damage. caused from working out too hard

catadromous

fishes that migrate from freshwater to spawn in the ocean (of a fish such as the eel) migrating down rivers to the sea to spawn. Anadromous fishes, including many salmonids, lampreys, shad, and sturgeon, spend most of their lives in the sea and migrate to freshwater to reproduce. American and European eels are catadromous fishes, which spend most of their lives in freshwater and migrate to the sea to reproduce.

Shark fin soup

health and full of nutrients, with claims of preventing cancer and other ailments) Shark fin soup is a traditional soup or stewed dish found in Chinese cuisine. The shark fins provide texture, while the taste comes from the other soup ingredients.[1] It is commonly served at special occasions such as weddings and banquets, or as a luxury item in Chinese cuisine. There are claims that shark fins prevent cancer;[9] however, there is no scientific evidence, and one study found shark cartilage generally to be of no value in cancer treatment.[10] Furthermore, there is no scientific evidence that shark fins can be used to treat any medical condition.[4] Sharks biomagnify toxins, so eating shark meat may raise the risk of dementia[11][12] and heavy metal poisoning such as mercury poisoning.[13][14]

Pressure ridge

ice formation formed by currents, tides, and winds A pressure ridge develops in an ice cover as a result of a stress regime established within the plane of the ice. Within sea ice expanses, pressure ridges originate from the interaction between floes, as they collide with each other

Myostatin

inhibits muscle growth Myostatin (also known as growth differentiation factor 8, abbreviated GDF-8) is a myokine, a protein produced and released by myocytes that acts on muscle cells' autocrine function to inhibit myogenesis: muscle cell growth and differentiation. In humans it is encoded by the MSTN gene.[6] Myostatin is a secreted growth differentiation factor that is a member of the TGF beta protein family.[7][8] Animals either lacking myostatin or treated with substances that block the activity of myostatin have significantly more muscle mass. Furthermore, individuals who have mutations in both copies of the myostatin gene have significantly more muscle mass and are stronger than normal. There is hope that studies into myostatin may have therapeutic application in treating muscle wasting diseases such as muscular dystrophy.[9]

Photometer

instrument for measuring intensity of light A photometer is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Most photometers convert light into an electric current using a photoresistor, photodiode, or photomultiplier

Rigor mortis

is the third stage of death. It is one of the recognizable signs of death, characterized by stiffening of the limbs of the corpse caused by chemical changes in the muscles postmortem. After death, respiration in an organism ceases, depleting the source of oxygen used in the making of adenosine triphosphate (ATP). ATP is required to cause separation of the actin-myosin cross-bridges during relaxation of muscle.[2] When oxygen is no longer present, the body may continue to produce ATP via anaerobic glycolysis. When the body's glycogen is depleted, the ATP concentration diminishes, and the body enters Rigor mortis because it is unable to break those bridges. Calcium enters the cytosol after death. Calcium is released into the cytosol due to the deterioration of the sarcoplasmic reticulum. Also, the breakdown of the sarcolemma causes additional calcium to enter the cytosol. The calcium activates the formation of actin-myosin cross-bridging. Once calcium is introduced into the cytosol, it binds to the troponin of thin filaments, which causes the troponin-tropomyosin complex to change shape and allow the myosin heads to bind to the active sites of actin proteins. In Rigor Mortis myosin heads continue binding with the active sites of actin proteins via adenosine diphosphate (ADP), and the muscle is unable to relax until further enzyme activity degrades the complex. Normal relaxation would occur by replacing ADP with ATP, which would destabilize the myosin-actin bond and break the cross-bridge. However, as ATP is absent, there must be a breakdown of muscle tissue by enzymes (endogenous or bacterial) during decomposition. As part of the process of decomposition, the myosin heads are degraded by the enzymes, allowing the muscle contraction to release and the body to relax.

Whale shark

largest known fish; endangered Shark species are increasingly becoming threatened because of commercial and recreational fishing pressures, the impact of non-shark fisheries on the seabed and shark prey species, and other habitat alterations such as damage and loss from coastal development and marine pollution.[6] Rising demands for shark products has increased pressure on shark fisheries, but little monitoring or management occurs of most fisheries.[7] Major declines in shark stocks have been recorded over the past few decades; some species had declined over 90% and population declines of 70% were not unusual by 1998.[8] In particular, harvesting young sharks before they reproduce severely impacts future populations. Sharks generally reach sexual maturity only after many years and produce few offspring in comparison to other fish species.[9] Conservationists estimate that up to 100 million sharks are killed by commercial and recreational fishing every year.[10][11] Sharks are often killed for shark fin soup, which some Asian countries regard as a status symbol. Fishermen capture live sharks, fin them, and dump the finless animal back into the water to die from suffocation or predators.[11][12] Sharks are also killed for their flesh in Europe and elsewhere.[13] In 2010, the Convention on International Trade in Endangered Species (CITES) rejected proposals from the United States and Palau that would have required countries to strictly regulate trade in several species of hammerhead, oceanic whitetip and dogfish sharks. The majority, but not the required two-thirds of voting delegates, approved the proposal. China, by far the world's largest shark consumer, and Japan, which battles all attempts to extend the Convention's protections to marine species, led the opposition.[18][19]

escapement

mechanical device that regulates movement Restrictions on subsistence fisheries will be necessary to meet the escapement goal. Officials said escapement goals will not be met without the restrictions.

metric ton vs short ton

metric ton = 2200 lbs short ton = 2000 lbs

subprime mortgage

mortgage for a borrower with a not-so-good credit rating In finance, subprime lending is the provision of loans to people who may have difficulty maintaining the repayment schedule. Historically, subprime borrowers were defined as having FICO scores below 600, although this threshold has varied over time.

Muscle hypertrophy

muscle enlargement from overuse Muscle hypertrophy involves an increase in size of skeletal muscle through a growth in size of its component cells. Two factors contribute to hypertrophy: sarcoplasmic hypertrophy, which focuses more on increased muscle glycogen storage; and myofibrillar hypertrophy, which focuses more on increased myofibril size. During a workout, increased blood flow to metabolically active areas causes muscles to temporarily increase in size, also known as being "pumped up" or getting "a pump".[7] About two hours after a workout and typically for seven to eleven days, muscles swell due to an inflammation response as tissue damage is repaired.[8] Longer-term hypertrophy occurs due to more permanent changes in muscle structure. Fancy way to say working out...

liberal

open to new behavior or opinions and willing to discard traditional values.

Regioselectivity

preferential formation of one constitutional isomer over another Regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions.[1][2] It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will add.

artisanal

relating to or characteristic of an artisan. made in a traditional or non-mechanized way. An artisan has both the creativity and the skill to make a product. Wandering around a local craft fair, you will often see artisans selling handicrafts like pot holders or beaded jewelry.

interstellar dust

small particles or grains of matter, primarily carbon and silicates, distributed throughout interstellar space This interstellar material is not uniformly distributed through space; it consists of a complex tangle of cool, dense clouds pushed and twisted by currents of hot, low-density gas. Although the cool clouds contain only 10 to 1000 atoms/cm^3 (fewer than in any laboratory vacuum on Earth), astronomers refer to them as dense clouds in contrast with the hot, low-density gas that fills the spaces between clouds. That thin gas contains only about 0.1 atom/cm^3

Bok globules

small, dark cloud only about 1 ly in diameter that contains 10 to 1000 solar masses of gas and dust, believed to be related to star formation In astronomy, Bok globules are isolated and relatively small dark nebulae, containing dense cosmic dust and gas from which star formation may take place.

Umbrella species

species selected for making conservation-related decisions, typically because protecting these species indirectly protects the many other species that make up the ecological community of its habitat. species whose being protected under the Endangered Species Act leads to the preservation of its habitat and all of the other organisms in its community

stellar parallax

the apparent shift in the position of a nearby star (relative to distant objects) that occurs as we view the star from different positions in Earth's orbit of the Sun each year Measuring the parallax p is very difficult because it is such a small angle. The visible star nearest the Sun, Alpha Centauri, has a parallax of only 0.76 arc second, and more distant stars have even smaller parallaxes. To see how small these angles are, imagine a dime 2 miles away from you. That dime covers an angle of about 1 arc second. Stellar parallaxes are so small that the first successful measurement of one did not happen until 1838, more than 200 years after the invention of the telescope. In 1989, the European Space Agency launched the satellite Hipparcos to measure stellar parallaxes from above the blurring effects of Earth's atmosphere. That small space telescope observed for 4 years, and the data were used to produce two parallax catalogs in 1997. One catalog contains 120,000 stars with parallaxes 20 times more accurate than ground-based measurements. The other catalog contains more than a million stars with parallaxes as accurate as ground-based parallaxes. Knowing accurate distances from the Hipparcos observations has given astronomers new insights into the nature of stars. The European Space Agency launched the Gaia spacecraft in 2013. It is designed to measure the parallaxes of a billion stars as faint as apparent visual magnitude +20. This will allow the first real three-dimensional map of our Galaxy; an initial catalog of results was released in 2016.

hydrostatic equilibrium

the balance of the inward gravitational force and the outward force of fusion within a star. This balance of forces is what keeps a main sequence star stable. The principle of hydrostatic equilibrium says that the pressure in each layer of a star must balance the weight on that layer. Consequently, as the weight increases from the surface of the star to its center, the pressure must also increase.

aquaculture

the cultivation of seafood Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, mariculture, algaculture (such as seaweed farming), and the cultivation of ornamental fish. Particular methods include aquaponics and integrated multi-trophic aquaculture, both of which integrate fish farming and aquatic plant farming.

carrion

the decaying flesh of dead animals

donning and doffing

the ease of putting a garment on and taking it off used when talking about PPE and how to properly take it off without contaminating yourself

Flagship species

the focus of public awareness campaigns aimed at generating interest in conservation in general; usually an interesting or charismatic species, such as the giant panda or tiger large and charismatic species used as spearheads for biodiversity conservation

light curve

the measure of a variable star's apparent magnitude as it brightens and dims with time

hysteresis

the phenomenon in which the value of a physical property lags behind changes in the effect causing it, as for instance when magnetic induction lags behind the magnetizing force.

Pharmacophore

the three-dimensional arrangement of atoms or groups of atoms responsible for the biological activity of a drug molecule A pharmacophore is an abstract description of molecular features that are necessary for molecular recognition of a ligand by a biological macromolecule.

intrinsic brightness

the total amount of light the star emits luminosity

multiple star systems

three or more stars that are bound by gravity Quaternary - Capella, a pair of giant stars orbited by a pair of red dwarfs, around 42 light years away from the Solar System. It has an apparent magnitude of around −0.47, making Capella one of the brightest stars in the night sky. Quintenary - Beta Capricorni: Beta Capricorni (β Capricorni, abbreviated Beta Cap, β Cap) is a multiple star system in the constellation of Capricornus and located 328 light-years from the Sun. Because it is near the ecliptic, Beta Capricorni can be occulted by the Moon,[2] and also (rarely) by planets. The system is believed to consist of five stars.[3] With binoculars or a small telescope, Beta Capricorni can be resolved into a binary pair. Sextenary - Beta Tucanae: Beta Tucanae (β Tuc, β Tucanae) is a group of six stars which appear to be at least loosely bound into a system in the constellation Tucana. Three of the stars are luminous and distinct enough to have been given their own Bayer designations, β¹ Tucanae through β³ Tucanae.[7] The system is approximately 140 light years from Earth. Septenary - Nu Scorpii: Nu Scorpii (ν Scorpii, abbreviated Nu Sco, ν Sco) is a multiple star system in the constellation of Scorpius. It is most likely a septuple star system,[5] consisting of two close groups (designated Nu Scorpii AB and CD) that are separated by 41 arcseconds.[5] Based on parallax measurements,[7] it is approximately 470 light-years from the Sun.

Apex predator

top of the food chain the top predator in an ecosystem

planet-walker

we really be made of star stuff doe

van der waals force

weak, short-range electrostatic attractive forces between uncharged molecules, arising from the interaction of permanent or transient electric dipole moments. a slight attraction that develops between the oppositely charged regions of nearby molecules The three types of van der Waals forces include: 1) dispersion (weak), 2) dipole-dipole (medium), and 3) hydrogen (strong). i have no idea

T Tauri Stars

young, variable pre-main-sequence stars associated with interstellar matter that show erratic changes in luminosity T Tauri stars (TTS) are a class of variable stars that are less than about ten million years old. This class is named after the prototype, T Tauri, a young star in the Taurus star-forming region. They are found near molecular clouds and identified by their optical variability and strong chromospheric lines.