Vocab v55

sugar cube polio vaccine

Sabin's live-virus, oral polio vaccine (administered in drops or on a sugar cube) soon replaced Salk's killed-virus, injectable vaccine in many parts of the world. In 1994 the WHO declared that naturally occurring poliovirus had been eradicated from the Western Hemisphere owing to repeated mass immunization campaigns with the Sabin vaccine in Central and South America. The only occurrences of paralytic poliomyelitis in the West after this time were the few cases caused by the live-virus vaccine itself.

Holographic principle

The holographic principle is a tenet of string theories and a supposed property of quantum gravity that states that the description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region—such as a light-like boundary like a gravitational horizon. First proposed by Gerard 't Hooft, it was given a precise string-theory interpretation by Leonard Susskind[1] who combined his ideas with previous ones of 't Hooft and Charles Thorn.[1][2] As pointed out by Raphael Bousso,[3] Thorn observed in 1978 that string theory admits a lower-dimensional description in which gravity emerges from it in what would now be called a holographic way. The prime example of holography is the AdS/CFT correspondence. The holographic principle was inspired by black hole thermodynamics, which conjectures that the maximal entropy in any region scales with the radius squared, and not cubed as might be expected. In the case of a black hole, the insight was that the informational content of all the objects that have fallen into the hole might be entirely contained in surface fluctuations of the event horizon. The holographic principle resolves the black hole information paradox within the framework of string theory.[4] However, there exist classical solutions to the Einstein equations that allow values of the entropy larger than those allowed by an area law, hence in principle larger than those of a black hole. These are the so-called "Wheeler's bags of gold". The existence of such solutions conflicts with the holographic interpretation, and their effects in a quantum theory of gravity including the holographic principle are not fully understood yet.[5]

How did we find our solar systems orbital duration within the galaxy?

You can use the orbital motion of the Sun to find the mass of the galaxy inside the Sun's orbit. By observing the radial velocity of distant galaxies in various directions around the sky, astronomers can tell that the Sun moves about 225 kilometers/second in the direction of Cygnus, carrying Earth and the other planets of our Solar System along with it. Because its orbit is a circle with a radius of 8.3 kpc, you can divide the circumference of the orbit by the velocity and find that the Sun completes a single orbit in about 225 million years.

Colliding Galaxies

You should not be surprised that galaxies collide with each other. The average separation between galaxies is only about 20 times their diameter, so galaxies should bump into each other fairly often, astronomically speaking. In comparison, stars almost never collide because the typical separation between stars is about 10^7 times their diameter. Consequently, a collision between two stars is about as likely as a collision between two gnats flitting about in a baseball stadium.

standard candle

an object for which we have some means of knowing its true luminosity, so that we can use its apparent brightness to determine its distance with the luminosity-distance formula

Simonetta Di Pippo

She's the lady we call if aliens pull up. The literal ambassador of all lifekind... Simonetta Di Pippo is an Italian astrophysicist and the current Director of the United Nations Office for Outer Space Affairs. Prior to joining UNOOSA, she served as Director of Human Spaceflight at ESA, and Director of the Observation of the Universe at the Italian Space Agency.

Curd

Solid portion of coagulated milk Curd is a dairy product obtained by coagulating milk in a process called curdling. The coagulation can be caused by adding rennet or any edible acidic substance such as lemon juice or vinegar, and then allowing it to coagulate. The increased acidity causes the milk proteins (casein) to tangle into solid masses, or curds. Milk that has been left to sour (raw milk alone or pasteurized milk with added lactic acid bacteria) will also naturally produce curds, and sour milk cheeses are produced this way. Producing cheese curds is one of the first steps in cheesemaking; the curds are pressed and drained to varying amounts for different styles of cheese and different secondary agents (molds for blue cheeses, etc.) are introduced before the desired aging finishes the cheese. The remaining liquid, which contains only whey proteins, is the whey. In cow's milk, 90 percent of the proteins are caseins.

Population I star

Stars with significant amounts of atoms heavier than helium; relatively young stars nearly always found in the galactic disk. The Sun is an intermediate Population I star.

why you have to crank old cars?

That was the starter motor—your arm and the crank that turned over the crankshaft. In those days, alternators and starter motors were expensive and unreliable, as were the batteries that held the charge to push the starter.

Gas chromatography-mass spectrometry

The GC-MS is composed of two major building blocks: the gas chromatograph and the mass spectrometer. The gas chromatograph utilizes a capillary column whose properties regarding molecule separation depend on the column's dimensions (length, diameter, film thickness) as well as the phase properties (e.g. 5% phenyl polysiloxane). The difference in the chemical properties between different molecules in a mixture and their relative affinity for the stationary phase of the column will promote separation of the molecules as the sample travels the length of the column. The molecules are retained by the column and then elute (come off) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass-to-charge ratio.

local group

The Local Group is the group of galaxies that includes our galaxy, the Milky Way. The group has more than 50 galaxies (including dwarf galaxies). Its center of mass is somewhere between the Milky Way and the Andromeda galaxy.

look-back time

The amount by which you look into the past when you look at a distant galaxy; a time equal to the distance to the galaxy in light-years. Telescopes as time machines. The look-back time to nearby objects is usually not significant. The lookback time to the Moon is only 1.3 seconds, to the Sun 8 minutes, and to the nearest star about 4 years. The Andromeda Galaxy has a look-back time of about 2 million years, but that is a mere eye blink in the lifetime of a galaxy. When astronomers look at more distant galaxies, the look-back time becomes an appreciable part of the age of the Universe.

spiral density wave theory

The conjecture that spiral arms in disk galaxies are caused by a pressure wave that rotates slowly around the galaxy, triggering star formation by compressing interstellar gas clouds. Basically, this theory states that the spiral arms of a disk galaxy are regions of the galaxy that are of higher density; and so we call them density waves. They are also areas that are moving more slowly than the galaxy's stars and gas. Originally, astronomers had the idea that the arms of a spiral galaxy were material. However, if this were the case, then the arms would become more and more tightly wound, since the matter nearer to the center of the galaxy rotates faster than the matter at the edge of the galaxy.[6] The arms would become indistinguishable from the rest of the galaxy after only a few orbits. This is called the winding problem.[7] Lin and Shu proposed in 1964 that the arms were not material in nature, but instead made up of areas of greater density, similar to a traffic jam on a highway. The cars move through the traffic jam: the density of cars increases in the middle of it. The traffic jam itself, however, moves more slowly.[1] In the galaxy, stars, gas, dust, and other components move through the density waves, are compressed, and then move out of them. More specifically, the density wave theory argues that the "gravitational attraction between stars at different radii" prevents the so-called winding problem, and actually maintains the spiral pattern.[8] _________________ Beginning in the late 1970s, Peter Goldreich, Frank Shu, and others applied density wave theory to the rings of Saturn.[9][10][11] Saturn's rings (particularly the A Ring) contain a great many spiral density waves and spiral bending waves excited by Lindblad resonances and vertical resonances (respectively) with Saturn's moons. The physics are largely the same as with galaxies, though spiral waves in Saturn's rings are much more tightly wound (extending a few hundred kilometers at most) due to the very large central mass (Saturn itself) compared to the mass of the disk.

Monolithic Collapse (Top-down Hypothesis)

The conjecture that the Milky Way Galaxy and other large galaxies formed mostly by gravitational collapse of a single large gas cloud. Olin Eggen, Donald Lynden-Bell, and Allan Sandage[2] in 1962, proposed a theory that disk galaxies form through a monolithic collapse of a large gas cloud. The distribution of matter in the early universe was in clumps that consisted mostly of dark matter. These clumps interacted gravitationally, putting tidal torques on each other that acted to give them some angular momentum. As the baryonic matter cooled, it dissipated some energy and contracted toward the center. With angular momentum conserved, the matter near the center speeds up its rotation. Then, like a spinning ball of pizza dough, the matter forms into a tight disk. Once the disk cools, the gas is not gravitationally stable, so it cannot remain a singular homogeneous cloud. It breaks, and these smaller clouds of gas form stars. Since the dark matter does not dissipate as it only interacts gravitationally, it remains distributed outside the disk in what is known as the dark halo. Observations show that there are stars located outside the disk, which does not quite fit the "pizza dough" model. It was first proposed by Leonard Searle and Robert Zinn [3] that galaxies form by the coalescence of smaller progenitors. Known as a top-down formation scenario, this theory is quite simple yet no longer widely accepted.

iron maiden

The iron maiden is a torture and execution device, consisting of an iron cabinet with a hinged front and spike-covered interior, sufficiently tall to enclose a human being. The first stories citing the iron maiden were composed in the 19th century. The use of iron maidens is a myth from the 18th century that was heightened by the belief that people of the Middle Ages were uncivilized; evidence of their popularity is difficult to prove.[1]

Galaxy masses

The most precise method for measuring the mass of a galaxy is called the rotation curve method (Figure 13-5). It requires knowing: (1) the true sizes of the orbits of stars or gas clouds within a galaxy, which in turn requires knowing the distance of that galaxy; and (2) the orbital speeds of the stars or gas clouds, measured from the Doppler shifts of their spectral lines. That is enough information to use Kepler's third law and find the mass of the part of the galaxy contained within the star orbits with measured sizes and velocities (look back to Chapter 12 Section 12-1e). The rotation curve method works only for galaxies near enough to be well resolved. More distant galaxies appear so small that astronomers cannot measure the radial velocity at different points across the galaxy and must use other, less precise, methods to estimate masses. The masses of galaxies cover a wide range. The smallest are a million times less massive than the Milky Way, and the largest contain as much as 50 times more mass than the Milky Way

More on spiral density wave theory

The most prominent theory about spiral arms is called the spiral density wave theory, which proposes that the arms are waves of compression that move around the galaxy triggering star formation. The density wave is a bit like a traffic jam behind a truck moving slowly along a highway. Seen from an airplane overhead, the jam seems a permanent, though slow-moving, feature. But individual cars overtake the jam from behind, slow down, move up through the jam, wait their turn, pass the truck, and resume speed along the highway. Similarly, clouds of gas overtake the spiral density wave, become compressed in the "traffic jam," and eventually move out in front of the arm, leaving the slower-moving density wave behind. Of course, star formation will occur where the gas clouds are compressed. Stars pass through the spiral arms unaffected, like bullets passing through a wisp of fog, but large clouds of gas slam into the spiral density wave from behind and are suddenly compressed. The spiral density wave series of images demonstrates how this movement occurs (Figure 12-12). You saw in Chapter 10 Section 10-4b that sudden compression could trigger the formation of stars in a gas cloud. Thus, new stars should form along the spiral arms. The spiral arms are not wound up by differential rotation because they are patterns, not physically connected structures. The brightest stars, the O and B stars, live such short lives that they never travel far from their birthplace and are found only along the arms. Their presence is what makes the spiral arms glow so brightly, because of both their own light and the emission from clouds of gas excited by UV radiation from the stars, as shown in Figure 12-13a. Lower-mass stars, like the Sun, live longer and have time to move out of the arms and continue their journey around the galaxy. The Sun might have formed in a star cluster almost 5 billion years ago when a gas cloud smashed into a spiral arm. Since that time, the Sun has escaped from its birth cluster and made about 20 trips around the galaxy, passing through spiral arms many times.

hubbles law

The observation that the farther away a galaxy is, the faster it is moving away. The linear relation between the distances to galaxies and the apparent velocity of recession. This relation between apparent velocity of recession and distance is known as the Hubble law, and the slope of the line is known as the Hubble constant, symbolized by H.

calcifiers

The ocean is full of organisms known as calcifiers - creatures large and small - that use carbonate and calcium ions dissolved in seawater to construct their shells and skeletons.

Kepler's laws of planetary motion

The orbit of a planet is an ellipse with the Sun at one of the two foci. A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit. The elliptical orbits of planets were indicated by calculations of the orbit of Mars. From this, Kepler inferred that other bodies in the Solar System, including those farther away from the Sun, also have elliptical orbits. The second law helps to establish that when a planet is closer to the Sun, it travels faster. The third law expresses that the farther a planet is from the Sun, the longer its orbit, and vice versa.

self sustaining star formation

The process by which the birth of stars compresses the surrounding gas clouds and triggers the formation of more stars; proposed to explain spiral arms.

Demosaicing

The process of converting raw picture data to another format, such as JPEG or TIF. A demosaicing algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array (CFA). It is also known as CFA interpolation or color reconstruction. Most modern digital cameras acquire images using a single image sensor overlaid with a CFA, so demosaicing is part of the processing pipeline required to render these images into a viewable format.

How Etch A Sketch works

The toy is a kind of plotter. The inside surface of the glass screen is coated with aluminium powder, which is then scraped off by a movable stylus, leaving a dark line on the light gray screen. The stylus is controlled by the two large knobs, one of which moves it vertically and the other horizontally. Turning both knobs simultaneously makes diagonal lines. To erase the picture, the user turns the toy upside down and shakes it. Doing this causes polystyrene beads to smooth out and re-coat the inside surface of the screen with aluminum powder. The "black" line merely exposes the darkness inside the toy. Scraping out large "black" areas allows enough light through to expose parts of the interior.

Tangata manu

The winner of a traditional competition on Rapa Nui (Easter Island). The ritual was an annual competition that brought relative peace between war-ridden clans. The Tangata manu was the winner of a traditional competition on Rapa Nui (Easter Island). The ritual was an annual competition to collect the first sooty tern (manu tara) egg of the season from the islet of Motu Nui, swim back to Rapa Nui and climb the sea cliff of Rano Kau to the clifftop village of Orongo. In the Rapa Nui mythology, the deity Make-make was the chief god of the birdman cult, and the other three deities associated with it were Hawa-tuu-take-take (the Chief of the eggs, a male god), his wife Vie Hoa, and another female deity named Vie Kenatea. Each of these four also had a servant god who was associated with him/her. The names of all eight would be chanted by contestants during the various rituals preceding the egg hunt. They had Birdman religion.

host-plant resistance (HPR)

This describes a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. Plants can sense being touched,[1] and they can use several strategies to defend against damage caused by herbivores. Many plants produce secondary metabolites, known as allelochemicals, that influence the behavior, growth, or survival of herbivores. These chemical defenses can act as repellents or toxins to herbivores, or reduce plant digestibility. The earliest land plants evolved from aquatic plants around 450 million years ago (Ma) in the Ordovician period. Many plants have adapted to iodine-deficient terrestrial environment by removing iodine from their metabolism, in fact iodine is essential only for animal cells. An important antiparasitic action is caused by the block of the transport of iodide of animal cells inhibiting sodium-iodide symporter (NIS). Many plant pesticides are glycosides (as the cardiac digitoxin) and cyanogenic glycosides which liberate cyanide, which, blocking cytochrome c oxidase and NIS, is poisonous only for a large part of parasites and herbivores and not for the plant cells in which it seems useful in seed dormancy phase. Iodide is not a pesticide, but is oxidized, by vegetable peroxidase, to iodine, which is a strong oxidant, able to kill bacteria, fungi and protozoa.[3] The geranium, for example, produces a unique chemical compound in its petals to defend itself from Japanese beetles. Within 30 minutes of ingestion the chemical paralyzes the herbivore. While the chemical usually wears off within a few hours, during this time the beetle is often consumed by its own predators.[27] Alkaloids are derived from various amino acids. Over 3000 known alkaloids exist, examples include nicotine, caffeine, morphine, cocaine, colchicine, ergolines, strychnine, and quinine.[29] Alkaloids have pharmacological effects on humans and other animals. Some alkaloids can inhibit or activate enzymes, or alter carbohydrate and fat storage by inhibiting the formation phosphodiester bonds involved in their breakdown.[30] Certain alkaloids bind to nucleic acids and can inhibit synthesis of proteins and affect DNA repair mechanisms. Alkaloids can also affect cell membrane and cytoskeletal structure causing the cells to weaken, collapse, or leak, and can affect nerve transmission.[31] Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly invoke an aversively bitter taste. Cyanogenic glycosides are stored in inactive forms in plant vacuoles. They become toxic when herbivores eat the plant and break cell membranes allowing the glycosides to come into contact with enzymes in the cytoplasm releasing hydrogen cyanide which blocks cellular respiration.

Virus

When infected, a host cell is forced to rapidly produce thousands of identical copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or virions, consisting of: (i) the genetic material, i.e. long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts; (ii) a protein coat, the capsid, which surrounds and protects the genetic material; and in some cases (iii) an outside envelope of lipids. The shapes of these virus particles range from simple helical and icosahedral forms to more complex structures. Most virus species have virions too small to be seen with an optical microscope as they are one hundredth the size of most bacteria. Viruses spread in many ways. One transmission pathway is through disease-bearing organisms known as vectors: for example, viruses are often transmitted from plant to plant by insects that feed on plant sap, such as aphids; and viruses in animals can be carried by blood-sucking insects. Influenza viruses are spread by coughing and sneezing. Norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal-oral route, passed by contact and entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. The variety of host cells that a virus can infect is called its "host range". This can be narrow, meaning a virus is capable of infecting few species, or broad, meaning it is capable of infecting many.[10] Viruses display a wide diversity of shapes and sizes, called 'morphologies'. In general, viruses are much smaller than bacteria. Most viruses that have been studied have a diameter between 20 and 300 nanometres. Some filoviruses have a total length of up to 1400 nm; their diameters are only about 80 nm.[69] Most viruses cannot be seen with an optical microscope, so scanning and transmission electron microscopes are used to visualise them.[70] To increase the contrast between viruses and the background, electron-dense "stains" are used. These are solutions of salts of heavy metals, such as tungsten, that scatter the electrons from regions covered with the stain. When virions are coated with stain (positive staining), fine detail is obscured. Negative staining overcomes this problem by staining the background only.[71] A complete virus particle, known as a virion, consists of nucleic acid surrounded by a protective coat of protein called a capsid. These are formed from identical protein subunits called capsomeres.[72] Viruses can have a lipid "envelope" derived from the host cell membrane. The capsid is made from proteins encoded by the viral genome and its shape serves as the basis for morphological distinction.[73][74] Virally-coded protein subunits will self-assemble to form a capsid, in general requiring the presence of the virus genome. Complex viruses code for proteins that assist in the construction of their capsid. Proteins associated with nucleic acid are known as nucleoproteins, and the association of viral capsid proteins with viral nucleic acid is called a nucleocapsid. The capsid and entire virus structure can be mechanically (physically) probed through atomic force microscopy.[75][76] In general, there are four main morphological virus types: ___________ Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm.[1] The virus replication occurs in seven stages, namely; Adsorption, Entry, Uncoating, Transcription / mRNA production, Synthesis of virus components, Virion assembly and Release (Liberation Stage). Adsorption It is the first step of viral replication. The virus attaches to the cell membrane of the host cell. It then injects its DNA or RNA into the host to initiate infection. In animal cells these viruses get into the cell through the process of endocytosis which works through fusing of the virus and fusing of the viral envelope with the cell membrane of the animal cell and in plant cell it enters through the process of pinocytosis which works on pinching of the viruses. Entry The cell membrane of the host cell invaginates the virus particle, enclosing it in a pinocytotic vacuole. This protects the cell from antibodies like in the case of the HIV virus. Uncoating Cell enzymes (from lysosomes) strip off the virus protein coat. This releases or renders accessible the virus nucleic acid or genome. Transcription / mRNA production For some RNA viruses, the infecting RNA produces messenger RNA (mRNA). This is translation of the genome into protein products. For others with negative stranded RNA and DNA, viruses are produced by transcription then translation. The mRNA is used to instruct the host cell to make virus components. The virus takes advantage of the existing cell structures to replicate itself. Synthesis of virus components The following components are manufactured by the virus through the host's existing organelles: Viral protein synthesis: virus mRNA is translated on cell ribosomes into two types of virus protein. Structural: the proteins which make up the virus particle are manufactured and assembled. Non - structural: not found in particle, mainly enzymes for virus genome replication. Viral nucleic acid synthesis (genome replication) new virus genome is synthesized, templates are either the parental genome or with single stranded nucleic acid genomes, newly formed complementary strands. By a virus called polymerate or replicate in some DNA viruses by a cell enzyme. This is done in rapidly dividing cells. Virion assembly A virion is simply an active or intact virus particle. In this stage, newly synthesized genome (nucleic acid), and proteins are assembled to form new virus particles. This may take place in the cell's nucleus, cytoplasm, or at plasma membrane for most developed viruses. Release (liberation stage) The viruses, now being mature are released by either sudden rupture of the cell, or gradual extrusion(budding) of enveloped viruses through the cell membrane. The new viruses may invade or attack other cells, or remain dormant in the cell. In the case of bacterial viruses, the release of progeny virions takes place by lysis of the infected bacterium. However, in the case of animal viruses, release usually occurs without cell lysis.

How to tell the difference between a black hole and a pulsar?

You have learned about X-ray binaries such as Hercules X-1 that contain a neutron star, and they emit X-rays much as a binary containing a black hole should. You can tell the difference in two ways. If the compact object emits pulses, you know it is a neutron star. Otherwise, you might check the mass of the object. If the mass of the compact object is greater than about 3 solar masses, the object cannot be a neutron star, and you can conclude that it must be a black hole

contingency

a future event or circumstance that is possible but cannot be predicted with certainty If you plan to walk home if the weather is nice, but bring subway fare just in case, then taking the subway is your contingency plan. A contingency is an event you can't be sure will happen or not.

rotation curve

a graph of orbital velocity versus radius in the disk of a galaxy A graph that plots rotational (or orbital) velocity against distance from the center for any object or set of objects.

distance ladder

a method used in astronomy where greater and greater distances are determined using many different measuring techniques that overlap to establish a sequence of increasing distances. The calibration used to build a distance scale reaching from the size of Earth to the most distant visible galaxies.

Cepheid Variable Stars

a particularly luminous type of pulsating variable star that follows a period-luminosity relation and hence is very useful for measuring cosmic distances Why they pulse? Pulsating variable stars are intrinsic variables as their variation in brightness is due to a physical change within the star. In the case of pulsating variables this is due to the periodic expansion and contraction of the surface layers of the stars. Cepheid Variable Stars lie on the region known as the instability strip on an H-R Diagram. As stars evolve, and the points that represent their temperatures and luminosities move in the H-R diagram, they can cross into the instability strip and start pulsating; they stop pulsating when they evolve out of the strip. Massive stars are larger and pulsate slower, just as large bells vibrate slower and have deeper tones. Lower-mass stars are less luminous and, being smaller, pulsate faster. This explains why, as first noticed by Leavitt, the long-period Cepheids are more luminous than the short-period Cepheids. That is now known as the period-luminosity relation, shown graphically in Figure 12-4. You might be interested to learn that the North Star, Polaris, is a Cepheid variable with a pulsation period of 4 days.

nociceptors

a sensory receptor for painful stimuli. Nociception is the sensory nervous system's response to certain harmful or potentially harmful stimuli. In nociception, intense chemical, mechanical, or thermal stimulation of sensory nerve cells called nociceptors produces a signal that travels along a chain of nerve fibers via the spinal cord to the brain.

penrose diagram

a two-dimensional diagram capturing the causal relations between different points in spacetime. It is an extension of a Minkowski diagram where the vertical dimension represents time, and the horizontal dimension represents space, and slanted lines at an angle of 45° correspond to light rays.

poor galaxy cluster

an irregularly shaped cluster that contains fewer than 1000 galaxies, many of which are spiral, and no giant ellipticals

Rennet

curdled milk from the stomach of an unweaned calf, containing rennin and used in curdling milk for cheese. Rennet is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease enzyme that curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a lipase. Rennet is used to separate milk into solid curds (for cheesemaking) and liquid whey, and so it or its substitutes is used in the production of most cheeses.

Retroreflector

device or surface that reflects light back to its source with a minimum of scattering A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence. Being directed, the retroflector's reflection is brighter than that of a diffuse reflector. Corner reflectors, and Cat's eye reflectors are the most used kinds. Corner reflector A set of three mutually perpendicular reflective surfaces, placed to form the internal corner of a cube, work as a retroreflector. The three corresponding normal vectors of the corner's sides form a basis (x, y, z) in which to represent the direction of an arbitrary incoming ray, [a, b, c]. When the ray reflects from the first side, say x, the ray's x-component, a, is reversed to −a, while the y- and z-components are unchanged. Therefore, as the ray reflects first from side x then side y and finally from side z the ray direction goes from [a, b, c] to [−a, b, c] to [−a, −b, c] to [−a, −b, −c] and it leaves the corner with all three components of its direction exactly reversed. Cat's eye Another common type of retroreflector consists of refracting optical elements with a reflective surface, arranged so that the focal surface of the refractive element coincides with the reflective surface, typically a transparent sphere and (optionally) a spherical mirror. In the paraxial approximation, this effect can be achieved with lowest divergence with a single transparent sphere when the refractive index of the material is exactly one plus the refractive index ni of the medium from which the radiation is incident (ni is around 1 for air). In that case, the sphere surface behaves as a concave spherical mirror with the required curvature for retroreflection. In practice, the optimal index of refraction may be lower than ni + 1 ≅ 2 due to several factors. For one, it is sometimes preferable to have an imperfect, slightly divergent retroreflection, as in the case of road signs, where the illumination and observation angles are different. Due to spherical aberration, there also exists a radius from the centerline at which incident rays are focused at the center of the rear surface of the sphere. Finally, high index materials have higher Fresnel reflection coefficients, so the efficiency of coupling of the light from the ambient into the sphere decreases as the index becomes higher. Commercial retroreflective beads thus vary in index from around 1.5 (common forms of glass) up to around 1.9 (commonly barium titanate glass).

aseptic

free from disease-causing microorganisms free from contamination caused by harmful bacteria, viruses, or other microorganisms. sterilize

arbitrage

the purchase of securities in one market for immediate resale in another to profit from a price discrepancy In economics and finance, arbitrage is the practice of taking advantage of a price difference between two or more markets: striking a combination of matching deals that capitalize upon the imbalance, the profit being the difference between the market prices at which the unit is traded.

As you can see in Figure 12-8, the orbital motions of the stars in the halo are strikingly different from those in the disk. In the halo, each star and globular cluster follows its own randomly tipped elliptical orbit. These orbits carry the stars and clusters far out into the spherical halo, where they move slowly, but when they fall back into the inner part of the galaxy, their velocities increase. Motions in the halo do not resemble a general rotation but are more like the random motions of a swarm of bees. In contrast, the stars in the disk of the galaxy move in the same direction in nearly circular orbits that lie in the plane of the galaxy. The Sun is a disk star and follows a circular orbit around the galaxy that always remains within the disk.

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Classifying galaxy clusters into rich and poor clusters reveals a fascinating and suggestive clue to the evolution of galaxies. In general, rich clusters tend to contain 80 percent to 90 percent E and S0 galaxies and few spirals. Poor clusters contain a larger percentage of spirals; and among isolated galaxies, those that are not in clusters, 80 percent to 90 percent are spirals. This suggests that a galaxy's environment is important in determining its structure and has led astronomers to suspect that one of the secrets to galaxy evolution lies in the collisions between galaxies. A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation.

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Everyone wants to change the world, but no one wants to change their life.

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Evidence of galaxy mergers is all around you. Our Milky Way Galaxy is a cannibal galaxy, snacking on the two Magellanic Clouds as they sail past it. Its tides are also pulling apart two other small satellite galaxies, the Sagittarius and Canis Major dwarf galaxies, producing great streamers of stars wrapped around the Milky Way. Almost certainly, our Galaxy has dined on other small galaxies in the past.

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For me it's the exact opposite. I overblow my failures and undermine my achievements to only feed my low self-esteem.

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If a snake is unable to shed its skin, it dies. In a way that is the same with humans. Many of us cling to ways that we were thinking that is still who we are when its not.

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Motivation is temporary, discipline is eternal.

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The results of such observations show that galaxies differ dramatically in size and luminosity. Irregular galaxies tend to be small, 5 percent to 25 percent the diameter of our Galaxy, and of low luminosity. Although they are common, they are easy to overlook. Our Milky Way Galaxy is large and luminous compared with most spiral galaxies, though astronomers know about a few spiral galaxies that are even larger and more luminous. Elliptical galaxies cover a wide range of diameters and luminosities. The largest, called giant ellipticals, are 10 times the diameter of our Milky Way Galaxy, but many so-called dwarf elliptical galaxies are only 1 percent the diameter of our Galaxy. Clearly, the diameter and luminosity of a galaxy do not determine its type. Some small galaxies are irregular, and some are elliptical. Some large galaxies are spiral, and some are elliptical. Other factors must influence the evolution of galaxies.

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There is so much interstellar dust in the plane of the Milky Way that you cannot observe the nucleus of our Galaxy at visual wavelengths. The image below is a radio image of the innermost 300 pc (1000 ly). Many of the features are supernova remnants (labeled SNR), and a few are star formation clouds. Peculiar features such as threads, the Arc, and the Snake may be gas trapped in magnetic fields. At the center of the image lies the strong radio source Sagittarius A (Sgr A), the location of the nucleus of our Galaxy.

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This is why shia labeouf-"stop giving up" meme is so funny to me. It is a caricature of this whole idea. He is screaming "stop giving up" as if a stranger on the internet can solve peoples' deep problems by absurdly yelling and flexing.

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You are made of atoms that were cooked up inside stars. Gravity draws matter together to make stars, and although nuclear fusion delays gravity's final victory, stars must eventually die. That process of star life and star death produces atoms heavier than helium and spreads them back into the interstellar medium, where they can become part of the gas clouds that form new stars. All of the atoms in your body except for the hydrogen were made inside stars. Some of your atoms, such as the carbon, were cooked up in the cores of medium-mass stars like the Sun and were puffed out into space when those stars died and produced planetary nebulae. Some of your atoms, such as the calcium in your bones, were made inside massive stars and were blown out into space during type II supernova explosions. Many of the iron atoms in your blood were made by the sudden fusion of carbon atoms when white dwarfs collapsed in Type Ia supernova explosions. Other heavy atoms, such as iodine in your thyroid gland, selenium in your nerve cells, and gold in your class ring, were also produced in the raging violence of supernova explosions. You are made of atoms scattered into space long ago by the violent deaths of stars. What are we? We are stardust.

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megaparsec (Mpc)

3.26 million ly

Barred spiral galaxy

A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about half of all spiral galaxies. Bars generally affect both the motions of stars and interstellar gas within spiral galaxies and can affect spiral arms as well.

What is meant by eutectic mixture?

A eutectic mixture is defined as a mixture of two or more components which usually do not interact to form a new chemical compound but, which at certain ratios, inhibit the crystallization process of one another resulting in a system having a lower melting point than either of the components. Eutectic point of water and glycol: A point at which water and glycol crystallize together The lowest possible freezing point occurs at the eutectic, but due primarily to their viscous nature, solutions of approximately 60 to 80 percent ethylene glycol, which includes the concentration of the eutectic mixture, have low and difficult-to- determine freezing points

thomson bearing

A linear-motion bearing or linear slide is a bearing designed to provide free motion in one direction. There are many different types of linear motion bearings.

rotation curve method

A method of determining a galaxy's mass by measuring the orbital velocity and orbital radius of stars in the galaxy

Passive infrared sensor (PIR Sensor)

A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications. PIR sensors detect general movement, but do not give information on who or what moved. For that purpose, an active IR sensor is required. Operating principles A PIR sensor can detect changes in the amount of infrared radiation impinging upon it, which varies depending on the temperature and surface characteristics of the objects in front of the sensor.[2] When an object, such as a person, passes in front of the background, such as a wall, the temperature at that point in the sensor's field of view will rise from room temperature to body temperature, and then back again. The sensor converts the resulting change in the incoming infrared radiation into a change in the output voltage, and this triggers the detection. Objects of similar temperature but different surface characteristics may also have a different infrared emission pattern, and thus moving them with respect to the background may trigger the detector as well. All objects with a temperature above absolute zero emit heat energy in the form of radiation. Usually this radiation isn't visible to the human eye because it radiates at infrared wavelengths, but it can be detected by electronic devices designed for such a purpose. For a D.C. current, the PIR Sensor works from 3.3v to 5v DC and gives a transistor-transistor logic (TTL) output which is directly given to a micro-controller or to relay through a transistor. The PIR sensor consists of a pyroelectric sensor and a Fresnel lens. This curved lens concentrates infrared radiation toward a detector's sensor. The sensor output is inverted by the transistor. Collector of the transistor is connected to the input pin forms the latch circuit which is set when PIR output goes high to indicate the presence of a warm body. Output of the latch pin operates the relay driving circuit formed by transistors arranged in emitter follower mode.

instability strip

A region of the H-R diagram containing stars that pulsate with a periodic variation in luminosity.

Coccolithophore

A very small planktonic alga carrying discs of calcium carbonate, which contributes to biogenous sediments. Coccoliths are produced by a biomineralization process known as coccolithogenesis.[12] Generally, calcification of coccoliths occurs in the presence of light, and these scales are produced much more during the exponential phase of growth than the stationary phase.[15] Although not yet entirely understood, the biomineralization process is tightly regulated by calcium signaling. Calcite formation begins in the golgi complex where protein templates nucleate the formation of CaCO3 crystals and complex acidic polysaccharides control the shape and growth of these crystals.[16] As each scale is produced, it is exported in a Golgi-derived vesicle and added to the inner surface of the coccosphere. This means that the most recently produced coccoliths may lie beneath older coccoliths.[17] Depending upon the phytoplankton's stage in the life cycle, two different types of coccoliths may be formed. While the exact function of the coccosphere is unclear, many potential functions have been proposed. Most obviously coccoliths may protect the phytoplankton from predators. It also appears that it helps them to create a more stable pH. During photosynthesis carbon dioxide is removed from the water, making it more basic. Also calcification removes carbon dioxide, but chemistry behind it leads to the opposite pH reaction; it makes the water more acidic. The combination of photosynthesis and calcification therefore even out each other regarding pH changes.[19] In addition, these exoskeletons may confer an advantage in energy production, as coccolithogenesis seems highly coupled with photosynthesis.

Why is the ego bad? I guess my issue with this is that I'm failing to see why having an identity that's constructed through beliefs is something we should get rid of. Isn't it human nature to find an identity?

Actually, I think you get it. I like the metaphor of dressing appropriately for the situation. I find that metaphor to be consistent with my own ego / self investigation while meditating. I think the key thing to realize is that the self or ego is constructed. It isn't an immutable part of you, you can change it and still be you. Or maybe the entire idea of a 'you' is artificial, but don't worry too much about that. The trick is to not be enslaved by your ego. When you really recognize that your ego is like your clothing then you are in much greater control of your life. And really realizing this is typically something that requires deep thought. Just reading about it or hearing someone else talk about it isn't enough. You need to observe what you think is your ego, and start tinkering with it yourself to really know how mutable it is.

Agronomy

Agronomy is the science and technology of producing and using plants in agriculture for food, fuel, fiber, and land restoration. It is both a humanitarian career and a scientific one. Agronomy has come to encompass work in the areas of plant genetics, plant physiology, meteorology, and soil science.

Alkaloids

Alkaloids are derived from various amino acids. Over 3000 known alkaloids exist, examples include nicotine, caffeine, morphine, cocaine, colchicine, ergolines, strychnine, and quinine.[29] Alkaloids have pharmacological effects on humans and other animals. Some alkaloids can inhibit or activate enzymes, or alter carbohydrate and fat storage by inhibiting the formation phosphodiester bonds involved in their breakdown.[30] Certain alkaloids bind to nucleic acids and can inhibit synthesis of proteins and affect DNA repair mechanisms. Alkaloids can also affect cell membrane and cytoskeletal structure causing the cells to weaken, collapse, or leak, and can affect nerve transmission.[31] Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly invoke an aversively bitter taste.[32] Alkaloids are a class of naturally occurring organic compounds that mostly contain basic nitrogen atoms. This group also includes some related compounds with neutral[2] and even weakly acidic properties.[3] Some synthetic compounds of similar structure may also be termed alkaloids.[4] In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.[5] Alkaloids are produced by a large variety of organisms including bacteria, fungi, plants, and animals.[6] They can be purified from crude extracts of these organisms by acid-base extraction, or solvent extractions followed by silica-gel column chromatography.[

searching for black holes

An isolated black hole is totally invisible because nothing can escape from the event horizon. But a black hole into which matter is flowing would be a source of X-rays. Of course, X-rays can't escape from inside the event horizon, but X-rays emitted by the heated matter flowing into the black hole can escape if the X-rays are emitted before the matter crosses the event horizon. An isolated black hole in space will not have much matter flowing into it, but a black hole in a binary system might receive a steady flow of matter transferred from its companion star. This suggests you can search for black holes by searching among X-ray binaries.

Falling into a black hole

Before you can search for real black holes, you must understand what theory predicts about the behavior of a black hole. To explore that idea, you can imagine that you leap, feet-first, into a Schwarzschild black hole. If you were to leap into a black hole of a few solar masses from a distance of an astronomical unit, the gravitational pull would not be very large, and you would fall slowly at first. Of course, the longer you fell and the closer you came to the center, the faster you would travel. Your wristwatch would tell you that you fell for about 2 months before you reached the event horizon. Your friends who stayed behind would see something different. They would see you falling more slowly as you came closer to the event horizon because, as described by general relativity, time slows down in curved space-time. This is known as time dilation. In fact, your friends would never actually see you cross the event horizon. To them you would fall more and more slowly until you seemed hardly to move. Generations later, your descendants could focus their telescopes on you and see you still inching closer to the event horizon. You, however, would have sensed no slowdown and would conclude that you had crossed the event horizon after about 2 months. Another relativistic effect would make it difficult to see you with normal telescopes. As light travels out of a gravitational field, it loses energy, and its wavelength grows longer. This is known as the gravitational redshift. Although you would notice no effect as you fell toward the black hole, your friends would need to observe at longer and longer wavelengths in order to detect you. While these relativistic effects seem merely peculiar, other effects would be quite unpleasant. Imagine again that you are falling feet-first toward the event horizon of a black hole. You would feel your feet, which would be closer to the black hole, being pulled in more strongly than your head. This is a tidal force, and at first it would be minor. As you fell closer, however, the tidal force would become very large. Another tidal force would compress you as your left side and your right side both fell toward the center of the black hole. For any black hole with a mass like that of a star, the tidal forces would crush you laterally and stretch you longitudinally long before you reached the event horizon (Figure 11-19). Needless to say, this would render you inoperative as a thoughtful observer. Your imaginary leap into a black hole is not frivolous. You now know how to find a black hole: Look for a strong source of X-rays that might be from matter compressed and stressed just before disappearing as it approaches the event horizon.

Biocrystallization

Biocrystallization is the formation of crystals from organic macromolecules by living organisms.[1] This may be a stress response, a normal part of metabolism such as processes that dispose of waste compounds, or a pathology. Template mediated crystallization is qualitatively different from in vitro crystallization. Inhibitors of biocrystallization are of interest in drug design efforts against lithiasis and against pathogens that feed on blood, since many of these organisms use this process to safely dispose of heme. Under severe stress conditions the bacteria Escherichia coli protects its DNA from damage by sequestering it within a crystalline structure.[2] This process is mediated by the stress response protein Dps and allows the bacteria to survive varied assaults such as oxidative stress, heat shock, ultraviolet light, gamma radiation and extremes of pH.[3][4] Blood feeding organisms digest hemoglobin and release high quantities of free toxic heme. To avoid destruction by this molecule, the parasite biocrystallizes heme to form hemozoin.[5] To date, the only definitively characterized product of hematin disposal is the pigment hemozoin. Hemozoin is per definitionem not a mineral and therefore not formed by biomineralization. Heme biocrystallization has been found in blood feeding organisms of great medical importance including Plasmodium, Rhodnius and Schistosoma. Heme biocrystallization is inhibited by quinoline antimalarials such as chloroquine. Targeting heme biocrystallization remains one of the most promising avenues for antimalarial drug development because the drug target is highly specific to the malarial parasite, and outside the genetic control of the parasite.

Chytrid fungus (Bd) (Chytridiomycosis)

Chytridiomycosis is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, a nonhyphal zoosporic fungus. Chytridiomycosis has been linked to dramatic population declines or even extinctions of amphibian species in western North America, Central America, South America, eastern Australia, East Africa (Tanzania),[1] and Dominica and Montserrat in the Caribbean. Much of the New World is also at risk of the disease arriving within the coming years.[2] The fungus is capable of causing sporadic deaths in some amphibian populations and 100% mortality in others. No effective measure is known for control of the disease in wild populations. Various clinical signs are seen by individuals affected by the disease. A number of options are possible for controlling this disease-causing fungus, though none has proved to be feasible on a large scale. The disease has been proposed as a contributing factor to a global decline in amphibian populations that apparently has affected about 30% of the amphibian species of the world.[3] However recent research has shown the evidence linking chytrid fungi and chytridiomycosis to global amphibian declines is minimal to-date.[4] A study suggests that changing global temperatures may be responsible for increased proliferation of chytridiomycosis. The rise in temperature has increased evaporation in certain forest environments that as a result has promoted cloud formation.[12] Experts propose that increased cloud cover might actually be decreasing the daytime temperature by blocking the sun, while at night the cloud cover serves as insulation to raise the nighttime temperature from its normal range.

Specifics of Cocaine and Crack

Cocaine is a hydrochloride salt in its powdered form, while crack cocaine is derived from powdered cocaine by combining it with water and another substance, usually baking soda (sodium bicarbonate). After cocaine and baking soda are combined, the mixture is boiled, and a solid forms. Once it's cooled and broken into smaller pieces, these pieces are sold as crack. The name crack derives from the crackling sound that is produced when the drug is heated and then smoked.

gamma ray bursts

During the 1960s, the United States put a series of satellites in orbit to watch for bursts of gamma-rays coming from Earth indicating nuclear weapons tests that would be violations of an international treaty. The experts were startled when the satellites detected about one gamma-ray burst coming from space per day. The Compton Gamma Ray Observatory launched in 1991 discovered that gamma-ray bursts were occurring all over the sky and not from any particular region. Starting in 1997, new satellites in orbit were able to detect gamma-ray bursts, determine their location in the sky, and immediately alert astronomers on the ground. When telescopes swiveled to image the locations of the bursts, they detected fading glows that resembled supernovae, and that has led to the conclusion that some relatively long gamma-ray bursts are produced by a kind of supernova explosion called a hypernova. Other gamma-ray bursts might be produced by the merger of two neutron stars or a neutron star and a black hole, and yet others by sudden shifts in the crusts of highly magnetized neutron stars.

Escape velocity relation to black holes

For example, to escape from Earth, a spaceship has to leave Earth's surface at 11.2 km/s (25,100 mph), but if you could launch spaceships from the top of a tower 1000 mi high, the escape velocity would be only 10.0 km/s (22,400 mph). An object massive enough and/or small enough could have an escape velocity greater than the speed of light. Relativity says that nothing can travel faster than the speed of light, so even photons would be unable to escape. Such a small, massive object could never be seen because light could not leave it. This was first noted by British astronomer Reverend John Mitchell in 1783, long before Einstein and relativity. If the core of a star collapses and contains more than about 3 solar masses, no force can stop the collapse. When the object reaches the size of a white dwarf, the collapse continues because degenerate electrons cannot support that much weight. It also cannot stop when it reaches the even smaller size of a neutron star because degenerate neutrons also cannot support that weight. No force remains to stop the object from collapsing to zero radius. As an object collapses, its density and the strength of its surface gravity increase; and if an object collapses to zero radius, its density and gravity become infinite. Mathematicians call such a point a singularity, but in physical terms it is difficult to imagine an object of zero radius. Some theorists think that a singularity is impossible and that the laws of quantum physics must somehow halt the collapse at a subatomic radius roughly 1020 times smaller than a proton. Astronomically, it seems to make little difference. If the contracting core of a star becomes small enough, the escape velocity in a region around it is so large that no light can escape. You can receive no information about the object or about the region of space near it. Such a region is called a black hole. Note that the term black hole refers to a volume of space, not just the singularity at the region's center. If the core of an exploding star collapsed to create a black hole, the expanding outer layers of the star could produce a supernova remnant, but the core would vanish without a trace. Albert Einstein's general theory of relativity treats space and time as a single entity—space-time. His equations showed that gravity could be described as a curvature of spacetime, and almost immediately astronomer Karl Schwarzschild found a way to solve the equations to describe the gravitational field around a single, nonrotating, electrically neutral lump of matter. That solution contained the first general relativistic description of a black hole, and nonrotating, electrically neutral black holes are now known as Schwarzschild black holes. Theorists such as Roy Kerr and Stephen Hawking have found ways to apply the sophisticated mathematical equations of the general theory of relativity and quantum mechanics to black holes that are rotating and have electrical charges. For this discussion the differences are minor, and you can proceed as if all black holes were Schwarzschild black holes. Schwarzschild's solution shows that if matter is packed into a small enough volume, then space-time curves back on themselves. Objects can still follow paths that lead into the black hole, but no path leads out, so nothing can escape, not even light. Consequently, the inside of the black hole is totally beyond the view of an outside observer. The event horizon is the boundary between the isolated volume of space-time and the rest of the Universe, and the radius of the event horizon is called the Schwarzschild radius, RS—the radius within which an object must shrink to become a black hole, as in Figure 11-17, and the point of no return for any object falling in later. Although Schwarzschild's work was highly mathematical, his conclusions were quite simple. The size of a black hole, its Schwarzschild radius, is simply proportional to its mass. A 3-solar-mass black hole will have a Schwarzschild radius of about 9 km, a 10-solar-mass black hole will have a Schwarzschild radius of 30 km, and so on. Note that even a very massive black hole would not be very large—just a few miles across. It is a common misconception to think of black holes as giant vacuum cleaners that will suck up everything in the Universe. A black hole is just a gravitational field, and at a large distance its gravity is no greater than that of a normal object of similar mass. If the Sun were replaced by a 1-solar-mass black hole, the orbits of the planets would not change at all. The gravity of a black hole becomes extreme only when you approach close to it. Figure 11-18 illustrates this by representing gravitational fields as curvature of the fabric of space-time. Physicists like to graph the strength of gravity around a black hole as curvature in a flat sheet. The graphs look like funnels in which the depth of the funnel indicates the strength of the gravitational field, but black holes themselves are not shaped like funnels; they are spheres or spheroids. In Figure 11-18, you should note that the strength of the gravitational field around the black hole becomes extreme only if you venture too close.

History of Easter Island

Geologically one of the youngest inhabited territories on Earth, Easter Island, located in the mid-Pacific Ocean, was, for most of its history, one of the most isolated. Its inhabitants, the Rapa Nui, have endured famines, epidemics of disease and cannibalism, civil war, environmental collapse, slave raids, various colonial contacts,[1][2] and have seen their population crash on more than one occasion. The ensuing cultural legacy has brought the island notoriety out of proportion to the number of its inhabitants. In December 1862, Peruvian slave raiders struck Easter Island. Violent abductions continued for several months, eventually capturing or killing around 1500 men and women, about half of the island's population. International protests erupted, escalated by Bishop Florentin-Étienne Jaussen of Tahiti. The slaves were finally freed in autumn, 1863, but by then most of them had already died of tuberculosis, smallpox and dysentery. Finally, a dozen islanders managed to return from the horrors of Peru, but brought with them smallpox and started an epidemic, which reduced the island's population to the point where some of the dead were not even buried.[23]

Dark Matter in Galaxies

Given the size and luminosity of a galaxy, astronomers can make a rough guess as to the amount of matter it should contain. Astronomers know how much light stars produce, and they know about how much matter there is between the stars, so it should be possible to estimate very roughly the mass of a galaxy from its luminosity. When astronomers measure the masses of galaxies, however, they often find that the measured masses are much larger than expected from the luminosities of the galaxies. You discovered this effect in Chapter 12 when you studied the rotation curve of our own Galaxy and concluded that it must contain large amounts of dark matter, especially in its outer regions (look back to Figure 12-9). Astronomer Vera Rubin found, in observations begun in the 1960s, that this also seems to be true of most nearby galaxies. Measured masses of galaxies amount to 10 to 100 times more mass than you can see. Dark matter is difficult to detect, and it is even harder to explain. Some astronomers have suggested that dark matter consists of low-luminous white dwarfs and brown dwarfs scattered through the halos of galaxies. Searches for white dwarfs and brown dwarfs in the halo of our Galaxy have found a few but not enough to make up most of the dark matter. The dark matter can't be hidden in vast numbers of black holes and neutron stars, because astronomers don't see the X-rays these objects would emit. The evidence indicates there is 10 to 100 times more dark matter than visible matter in galaxies, and if there were that many black holes they would produce X-rays that would be easy to detect. Furthermore, recent images from the Chandra X-ray Observatory indicate that a collision between two galaxy clusters caused their gas and dark matter components to separate. Because observations imply that the dark matter can't be composed of familiar objects or material, astronomers are forced to conclude that the dark matter is made up of unexpected forms of matter. Until recently, neutrinos were thought to be massless, but studies now suggest they have a very small mass. Thus they can be part of the dark matter, but their masses are too low to make up all of the dark matter. There must be some other undiscovered form of matter in the Universe that is detectable only by its gravitational field. Dark matter remains one of the fundamental unresolved problems of modern astronomy. Observations of galaxies and clusters of galaxies reveal that 90 percent to 95 percent of the matter in the Universe is dark matter. The Universe you see—the kind of matter that you and the stars are made of—has been compared to the foam on an invisible ocean.

Supernova nucleosynthesis

Heat and Pressure from the Supernova that created elements heavier than iron. A supernova is a violent explosion of a star that occurs under two principal scenarios. The first is that a white dwarf star, which is the remnant of a low-mass star that has exhausted its nuclear fuel, undergoes a thermonuclear explosion after its mass is increased beyond its Chandrasekhar limit by accreting nuclear-fuel mass from a more diffuse companion star (usually a red giant) with which it is in binary orbit. The resulting runaway nucleosynthesis completely destroys the star and ejects its mass into space. The second, and about threefold more common, scenario occurs when a massive star (12-35 times more massive than the sun), usually a supergiant at the critical time, reaches nickel-56 in its core nuclear fusion (or burning) processes. Without exothermic energy from fusion, the core of the pre-supernova massive star loses heat needed for pressure support, and collapses owing to the strong gravitational pull. The energy transfer from the core collapse causes the supernova display.[19] The nickel-56 isotope has one of the largest binding energies per nucleon of all isotopes, and is therefore the last isotope whose synthesis during core silicon burning releases energy by nuclear fusion, exothermically. The binding energy per nucleon declines for atomic weights heavier than A = 56, ending fusion's history of supplying thermal energy to the star. The thermal energy released when the infalling supernova mantle hits the semi-solid core is very large, about 10^53 ergs, about a hundred times the energy released by the supernova as the kinetic energy of its ejected mass. Dozens of research papers have been published in the attempt to describe the hydrodynamics of how that small one percent of the in falling energy is transmitted to the overlying mantle in the face of continuous infall onto the core. That uncertainty remains in the full description of core-collapse supernovae.[citation needed] Nuclear fusion reactions that produce elements heavier than iron absorb nuclear energy and are said to be endothermic reactions. When such reactions dominate, the internal temperature that supports the star's outer layers drops. Because the outer envelope is no longer sufficiently supported by the radiation pressure, the star's gravity pulls its mantle rapidly inward. As the star collapses, this mantle collides violently with the growing incompressible stellar core, which has a density almost as great as an atomic nucleus, producing a shockwave that rebounds outward through the unfused material of the outer shell. The increase of temperature by the passage of that shockwave is sufficient to induce fusion in that material, often called explosive nucleosynthesis.[2][20] The energy deposited by the shockwave somehow leads to the star's explosion, dispersing fusing matter in the mantle above the core into interstellar space.

Iron star

In astronomy, an iron star is a hypothetical type of compact star that could occur in the universe in the extremely far future, after perhaps 10^1500 years. The premise behind iron stars states that cold fusion occurring via quantum tunnelling would cause the light nuclei in ordinary matter to fuse into iron-56 nuclei. Fission and alpha-particle emission would then make heavy nuclei decay into iron, converting stellar-mass objects to cold spheres of iron.[1] The formation of these stars is only a possibility if protons do not decay. Though the surface of a neutron star may be iron according to some predictions, it is distinct from an iron star. By the end of 10^10^26 to 10^10^76 years, iron stars would have collapsed into neutron stars and black holes.[1]

Curdling

In cookery, curdling is the breaking of an emulsion or colloid into large parts of different composition through the physico-chemical processes of flocculation, creaming, and coalescence. Curdling is intentional and desirable in making cheese and tofu; unintentional and undesirable in making a sauce or a custard. Curdling occurs naturally in cows' milk, if it is left open to air for a few days in a warm environment. Milk is composed of several compounds, primarily fat, protein, and sugar. The protein in milk is normally suspended in a colloidal (colloid) solution, which means that the small protein molecules float around freely and independently. These floating protein molecules refract light and contribute (with the suspended fat) to the white appearance of milk. Normally these protein molecules repel each other, allowing them to float about without clumping, but when the pH of their solution changes, they can attract one another and form clumps. This is what happens when milk curdles, as the pH drops and becomes more acidic, the protein (casein and others) molecules attract one another and become "curdles" floating in a solution of translucent whey. This clumping reaction happens more swiftly at warmer temperatures than it does at cold temperatures.

Hemocytometer

Instrument used in counting blood cells

Interesterified fat

Interesterified fat is a type of oil where the fatty acids have been moved from one triglyceride molecule to another. This is generally done to modify the melting point, slow rancidification and create an oil more suitable for deep frying or making margarine with good taste and low saturated fat content. It is not the same as partial hydrogenation which produces trans fatty acids, but interesterified fats used in the food industry can come from hydrogenated fat, for simplicity and frugality.

Irregular galaxies

Irregular galaxies (classified Irr) are a chaotic mix of gas, dust, and stars with no obvious nuclear bulge or spiral arms. The Large and Small Magellanic Clouds are visible to the unaided eye as hazy patches in the Southern Hemisphere sky. Telescopic images show that they are irregular galaxies that are interacting gravitationally with our own much larger Galaxy. Star formation is rapid in the Magellanic Clouds. The bright pink regions are emission nebulae excited by newborn O and B stars. The brightest nebula in the Large Magellanic Cloud is called the Tarantula Nebula.

densest element

It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with an experimentally measured (using x-ray crystallography) density of 22.59 g/cm3. Lead is 11.35, the 24th densest element https://www.lenntech.com/periodic-chart-elements/density.htm

Lifecycle of the Japanese beetle

Larvae feed on roots underground, while adults feed on leaves and stems. Ova are laid individually, or in small clusters near the soil surface.[9] Within approximately two weeks, the ova hatch, the larvae feeding on fine roots and other organic material. As the larvae mature, they become c-shaped grubs which consume progressively coarser roots and may do economic damage to pasture and turf at this time. Larvae hibernate in small cells in the soil, emerging in the spring when soil temperatures rise again.[9] Within 4-6 weeks of breaking hibernation, the larvae will pupate. Most of the beetle's life is spent as a larva, with only 30-45 days spent as an imago. Adults feed on leaf material above ground, using pheromones to attract other beetles and overwhelm plants, skeletonizing leaves from the top of the plant downward. The aggregation of beetles will alternate daily between mating, feeding, and ovipositing. An adult female may lay as many as 40-60 ova in her lifetime.[9] Throughout the majority of the Japanese beetle's range, its lifecycle takes one full year, however in the extreme northern parts of its range, as well as high altitude zones as found in its native Japan, development may take two years.[10]

Bottom-up theory galaxy formation

More recent theories include the clustering of dark matter halos in the bottom-up process. Instead of large gas clouds collapsing to form a galaxy in which the gas breaks up into smaller clouds, it is proposed that matter started out in these "smaller" clumps (mass on the order of globular clusters), and then many of these clumps merged to form galaxies,[4] which then were drawn by gravitation to form galaxy clusters. This still results in disk-like distributions of baryonic matter with dark matter forming the halo for all the same reasons as in the top-down theory. Models using this sort of process predict more small galaxies than large ones, which matches observations. Astronomers do not currently know what process stops the contraction. In fact, theories of disk galaxy formation are not successful at producing the rotation speed and size of disk galaxies. It has been suggested that the radiation from bright newly formed stars, or from an active galactic nucleus can slow the contraction of a forming disk. It has also been suggested that the dark matter halo can pull the galaxy, thus stopping disk contraction.[5] The Lambda-CDM model is a cosmological model that explains the formation of the universe after the Big Bang. It is a relatively simple model that predicts many properties observed in the universe, including the relative frequency of different galaxy types; however, it underestimates the number of thin disk galaxies in the universe.[6] The reason is that these galaxy formation models predict a large number of mergers. If disk galaxies merge with another galaxy of comparable mass (at least 15 percent of its mass) the merger will likely destroy, or at a minimum greatly disrupt the disk, and the resulting galaxy is not expected to be a disk galaxy (see next section). While this remains an unsolved problem for astronomers, it does not necessarily mean that the Lambda-CDM model is completely wrong, but rather that it requires further refinement to accurately reproduce the population of galaxies in the universe.

narrow bipolar event

Narrow bipolar pulses are high-energy, high-altitude, intra-cloud electrical discharges associated with thunderstorms. NBP are similar to other forms of lightning events such as return strokes and dart leaders, but produce an optical emission of at least an order of magnitude smaller. They typically occur in the 10-20 km altitude range and can emit a power on the order of a few hundred gigawatts. They produce far-field asymmetric bipolar electric field change signatures (called narrow bipolar events).

Components of our galaxy

Our Galaxy, like many others, contains two primary components—a disk and a sphere. The disk component consists of all matter confined to the plane of rotation—that is, everything in the disk itself. This includes stars, open star clusters, and nearly all of the galaxy's gas and dust. As you will learn in more detail in the next section, because the disk contains lots of gas, it is the site of most of the star formation in the galaxy. Consequently, the disk is illuminated by recently formed brilliant, blue, massive stars and has an overall relatively blue color. Observations made at other than visual wavelengths can help astronomers peer through the dust and gas. Infrared and radio photons have wavelengths long enough to be unaffected by the dust. Thus, a map of the sky at long infrared wavelengths reveals the disk of our Galaxy, which you can see in Figure 12-7. The most striking features of the disk component are the spiral arms—long curves of bright stars, star clusters, gas, and dust. Such spiral arms are easily visible in other galaxies, and you will see later how astronomers found that our own Galaxy has a spiral pattern. The second component of our Galaxy is the spherical component, which includes all matter in our Galaxy scattered in a roughly spherical distribution around the center. This includes a large halo and the central bulge. The halo is a spherical cloud of thinly scattered stars and globular star clusters. It contains only about 2 percent as many stars as the disk of the galaxy and has very little gas and dust. Thus, with no raw material available, no new stars are forming in the halo. In fact, the halo stars are mostly old, cool giants or dim lower-main-sequence stars plus old white dwarfs that are difficult to detect but have been revealed by recent careful studies. Astronomers can map the halo of our Galaxy by studying the more easily detected giant stars. The central bulge is the dense cloud of stars that surrounds the center of our Galaxy. It has a radius of about 2 kpc and is a slightly flattened spheroid. It is hard to observe because thick dust in the disk scatters and absorbs radiation of visible wavelengths, but observations at longer wavelengths can penetrate the dust. The bulge seems to contain little gas and dust, and there is not much star formation there. Most of the stars in the central bulge are old, cool stars like those in the halo.

Are potato eyes poisonous?

Potentially, they could be. When a potato or part of a potato plant is growing or undergoing photosynthesis, the green parts of the plant are producing a neurotoxin called solanine. The eyes of a potato are the part that potentially grow a new potato plant, if they get enough sunlight and there is enough moisture in the potato. The shoots and leaves that grow from the eyes can have a high enough concentration of solanine to make you ill. If you ate an entire meal of nothing but potato greens, you would probably get quite ill - possibly die without prompt treatment. When a potato gets enough light, the skin turns green. This indicates photosynthesis is occurring, and some solanine is being produced. You could probably eat an entire meal of such potatoes, however, even without skinning them, and suffer no ill effects at all. Potatoes are a member of the nightshade family. Atropa belladonna, also known as deadly nightshade, has very high concentrations of similar neurotoxic alkaloids in its fruit and leaves, (atropine, hyoscine (scopolamine), and hyoscyamine) and was once a source of poison used to murder people. A few berries would make an adult grow ill and/or hallucinate, and a few more would kill. The concentrated juice was a very effective poison. Back to potatoes, though - if the eyes are not green and nothing is growing from them, they have little to no solanine. Even if they do have young shoots visible as little bumps, the potato is safe, and besides, the little bumps are easy to snap off if one is concerned. ______________ Solanine is a glycoalkaloid poison found in species of the nightshade family within the genus Solanum, such as the potato, the tomato, and the eggplant. It can occur naturally in any part of the plant, including the leaves, fruit, and tubers. Solanine has pesticidal properties, and it is one of the plant's natural defenses. Solanum glycoalkaloids can inhibit cholinesterase, disrupt cell membranes, and cause birth defects.[6] One study suggests that the toxic mechanism of solanine is caused by the chemical's interaction with mitochondrial membranes. Experiments show that solanine exposure opens the potassium channels of mitochondria, increasing their membrane potential. This, in turn, leads to Ca2+ being transported from the mitochondria into the cytoplasm, and this increased concentration of Ca2+ in the cytoplasm triggers cell damage and apoptosis.

If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words?

Proposed by Feynman. His response: I believe it is the atomic hypothesis that all things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied.

Time + Awareness can usually solve any problem.

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Rich galaxy clusters

A cluster containing 1000 or more galaxies, usually mostly ellipticals, scattered over a volume only a few megaparsecs in diameter.

Elliptical galaxy

A galaxy shaped like a round or flattened ball, generally containing only old stars Elliptical galaxies are round or elliptical, contain no visible gas and dust, and lack hot, bright stars. They are classified with a numerical index ranging from 1 to 7; E0s are round, and E7s are highly elliptical.

where did cows originate

About 10,000 years ago, ancient people domesticated cows from wild aurochs (bovines that are 1.5 to two times as big as domestic cattle) in two separate events, one in the Indian subcontinent and one in Europe.

metal (astronomy)

All atoms heavier than helium

Corner reflector

Cavity formed by two or three smooth planar surfaces intersecting at right angles. Electromagnetic waves entering a corner reflector are reflected directly back toward the source. A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects waves back directly towards the source, but translated. The three intersecting surfaces often have square shapes Used on bike reflectors. Five arrays of optical corner reflectors have been placed on the Moon for use by Lunar Laser Ranging experiments observing a laser's time-of-flight to measure the Moon's orbit more precisely than was possible before. The three largest were placed by NASA as part of the Apollo program, and the Soviet Union's built two smaller ones into the Lunokhod rovers.

Cheese

Cheese is a dairy product derived from milk that is produced in a wide range of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, the milk is usually acidified, and adding the enzymes of rennet causes coagulation. The solids are separated and pressed into final form.[1] Some cheeses have molds on the rind, the outer layer, or throughout. Most cheeses melt at cooking temperature. Over a thousand types of cheese exist and are currently produced in various countries. Their styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether they have been pasteurized, the butterfat content, the bacteria and mold, the processing, and how long they have been aged for. Herbs, spices, or wood smoke may be used as flavoring agents. The yellow to red color of many cheeses is produced by adding annatto. Other ingredients may be added to some cheeses, such as black pepper, garlic, chives or cranberries. A cheesemonger, or specialist seller of cheeses, may have expertise with selecting the cheeses, purchasing, receiving, storing and ripening them. For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon juice. Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, then the addition of rennet completes the curdling. Vegetarian alternatives to rennet are available; most are produced by fermentation of the fungus Mucor miehei, but others have been extracted from various species of the Cynara thistle family. Cheesemakers near a dairy region may benefit from fresher, lower-priced milk, and lower shipping costs. Cheese is valued for its portability, long life, and high content of fat, protein, calcium, and phosphorus. Cheese is more compact and has a longer shelf life than milk, although how long a cheese will keep depends on the type of cheese.[3] Hard cheeses, such as Parmesan, last longer than soft cheeses, such as Brie or goat's milk cheese. The long storage life of some cheeses, especially when encased in a protective rind, allows selling when markets are favorable. Vacuum packaging of block-shaped cheeses and gas-flushing of plastic bags with mixtures of carbon dioxide and nitrogen are used for storage and mass distribution of cheeses in the 21st century.[3] Curdling A required step in cheesemaking is separating the milk into solid curds and liquid whey. Usually this is done by acidifying (souring) the milk and adding rennet. The acidification can be accomplished directly by the addition of an acid, such as vinegar, in a few cases (paneer, queso fresco). More commonly starter bacteria are employed instead which convert milk sugars into lactic acid. The same bacteria (and the enzymes they produce) also play a large role in the eventual flavor of aged cheeses. Most cheeses are made with starter bacteria from the Lactococcus, Lactobacillus, or Streptococcus families. Swiss starter cultures also include Propionibacter shermani, which produces carbon dioxide gas bubbles during aging, giving Swiss cheese or Emmental its holes (called "eyes"). Ripening A newborn cheese is usually salty yet bland in flavor and, for harder varieties, rubbery in texture. These qualities are sometimes enjoyed—cheese curds are eaten on their own—but normally cheeses are left to rest under controlled conditions. This aging period (also called ripening, or, from the French, affinage) lasts from a few days to several years. As a cheese ages, microbes and enzymes transform texture and intensify flavor. This transformation is largely a result of the breakdown of casein proteins and milkfat into a complex mix of amino acids, amines, and fatty acids.

what causes milk to go bad

Continual and rapid temperature shifts can breed bacteria such as lactococci and lactobacilli. Milk spoils when bacteria converts the lactose into glucose and galactose, producing lactic acid. Lactic acid creates casein and then forms a curd that can quickly curdle the milk within 24 hours. Once milk starts curdling toward the bottom of the jug, it's considered spoiled and should immediately be discarded. As bacteria forms on the sugary butterfat, mold also grows and spoils the milk even further.

how many kangaroos are eaten each year?

Current estimates indicate that there may be between 35 and 50 million kangaroos in Australia. In 2002, the number of kangaroos allowed to be shot by commercial hunters was increased from 5.5 million to 7 million per year.

Supermassive Black Holes in Galaxies

Doppler shift measurements show that the stars near the centers of many galaxies are orbiting very rapidly. To hold stars in such small, short-period orbits, the centers of those galaxies must contain masses of a million to a few billion solar masses, yet no object is visible. The evidence seems to require that the nuclei of many galaxies contain supermassive black holes. You saw in Chapter 12 Section 12-4 that the Milky Way Galaxy contains a supermassive black hole at its center. Evidently that is typical of galaxies. It is a common misconception that the orbits of stars throughout a galaxy are controlled by the central black hole. The masses of those black holes, large as they might seem, are negligible compared with a galaxy's mass. The 4.3-million-solar-mass black hole at the center of the Milky Way Galaxy contains only a thousandth of 1 percent of the total mass of the galaxy.

moai

Easter Island is most famous for its nearly 1,000 extant monumental statues, called moai, created by the early Rapa Nui people. In 1995, UNESCO named Easter Island a World Heritage Site, with much of the island protected within Rapa Nui National Park.

why graft trees?

Grafting and budding are commonly used to propagate most fruit and nut tree cultivars. ... Grafting a plant whose roots are prone to a soil disease onto a rootstock that is resistant to that disease would allow that plant to grow successfully where it would otherwise have problems.

Hemozoin

Haemozoin is a disposal product formed from the digestion of blood by some blood-feeding parasites. These hematophagous organisms such as malaria parasites (Plasmodium spp.), Rhodnius and Schistosoma digest haemoglobin and release high quantities of free heme, which is the non-protein component of hemoglobin. Heme is a prosthetic group consisting of an iron atom contained in the center of a heterocyclic porphyrin ring. Free heme is toxic to cells, so the parasites convert it into an insoluble crystalline form called hemozoin. In malaria parasites, hemozoin is often called malaria pigment.

Lithiasis

Lithiasis (formation of stones) is a global human health problem. Stones can form in both urinary and gastrointestinal tracts. Related to the formation of stones is the formation of crystals; this can occur in joints (e.g. gout) and in the viscera.[6]

Different cultured meat companies

Memphis Meats, is arguably the most famous cell based meat company in part because of notable investors including Bill Gates and Richard Branson. Memphis Meats has successfully cultivated and harvested cell based beef, chicken, and duck inside of bioreactors. The company expects to get the costs down and have the product in stores by 2021. Memphis Meats has a number of patents pending on specific developments that may enable the company to decrease costs and commercialize their products faster than the competition. The patents address cell immortalization, cell density, amino acid synthesis, and genetically engineered cell lines. It is unclear of the exact methods Memphis Meats will use to reduce the cost of their cell based meat, but based on the patents filed, it seems Memphis is looking to remove costly growth serums from their processes and possibly incorporate gene editing CRISPR based technologies. Future Meat Technologies has a proprietary technology for growing fibroblast cells inside of bioreactor systems. Fibroblasts are connective tissue cells (like those found underneath the skin) that grow rapidly and can be differentiated into fat or muscle cells without any genetic modification or foreign genetic material added. The fat and muscle cells are then grown in a bioreactor using animal free cell culture medium that Future Meat has developed and patented. The company has also developed a process for cleaning toxic waste (a major challenge involved in producing cell based meat) and recycling the medium to improve efficiency and reduce costs. This proprietary cleaning process is similar to a water filtration system that contains solid particles that bind to the toxic waste molecules (mostly ammonia) and filters them out of the bioreactor. Future Meat has a unique strategy to bring their cell based meat to market, which the company calls: distributive manufacturing. When operative, Future Meats sells tissue cells, cell culture media and bioreactors (that include the filtration system) to farmers who could then grow the meat themselves. In this model, Future Meat does not want to replace farmers, but provide them new tools to farm with. Yaakov Nahmias, founder of Future Meat has stated that using the bioreactor will be relatively easy for farmers to adopt as it is a "plug and play" operation. The entire cell growth process takes 10-12 days with 2 days to prepare and clean the system for the next batch. The system allows farmers to be more nimble as they can swiftly respond to changing consumer demands for what meat type they grow. MeaTech is developing a 3D stem cell printing technology for cell based meat production. The company's founder and CEO Sharon Fima is an expert in complex 3D printing processes. MeaTech isolates somatic stem cells from a bovine umbilical cord and grows these cells inside of a bioreactor. The cells are then differentiated into bioinks or edible inks to 3D print different cell types such as fat and muscle. Once the cells are 3D printed they are placed into incubators to mature and grow. This unique process allows for the development of structured meats such as steaks. Meatable is licensing a proprietary technology called,OPTi-OX to develop cell based meat. OPTi-OX is a form of genetic intervention that converts pluripotent stem cells into any desired cell type. This means that Meatable can take a stem cell sourced from a calf's umbilical cord and reprogram the cell to turn into a fat cell or a muscle cell — two types of cells that are found in every meat product. - Faster Doubling Time: 20,000 strands of muscle fiber in 3-5 days with OPTi-OX. - Indefinite Life-Span: a single vial of stem cells sourced from a single umbilical cord proliferate indefinitely. - Animal Free Serum: The cells grow off of E8, a completely animal free cell culture medium made up of amino acids, vitamins, minerals and salts. At the end of 2019, Meatable completed a $12 million funding round and announced an anticipated prototype for the end of 2020. This prototype is not expected to be like the meat slurry or blended products we have seen from other companies, rather Meatable's process enables production of full cuts of meat. The 2020 prototype is expected to be a fully structured pork chop, not bone in. IntegriCulture: The most expensive part of making cell based meat is the growth serum in the cell culture media. The growth serum + media can be recycled through what is scientifically referred to as a co-culture system. This means setting up a system that mimics how cells behave in the body, where one tissue produces waste that another type of tissue can reuptake and reuse as food. IntegriCulture has created a proprietary technology called CulNet, which is a system of three tanks with three different cell types simulating an environment that mimics the interaction between cells as they would behave in the animal's body. IntegriCulture's CulNet system will provide an advantage of recycling serum and reducing waste build up therefore reducing cost associated with producing a variety of cell types (muscle, fat, liver, connective tissue, etc.). In March 2019, Hiroki Ando, President and CEO of Nissin Food Holdings (ramen powerhouse and producer of the American brand, Cup Noodle) announced the company had been working with researchers at the Institute of Industrial Science and Technology (Uni. Tokyo) to produce diced steak using cell based technology. The research group had success in the maturation process of bovine muscle cells feeding the cells vitamin C and using collagen gel as a scaffold structure. Shiok Meats is developing cell based shrimp prawns, crabs, and lobster. To start, Shiok is focusing on shrimp and unveiled its first prototype in April 2019, which lacked texture and was a meat slurry formed into a shrimp dumpling, yet retained shrimp flavor and scent. Shiok is focusing on making a more structured shrimp product for a higher end market, but would not have a shell or eyeballs and just be the edible tissue portion. The company has reported it currently takes them 4-6 weeks to go from stem cell to meat and costs about $5000-$7000 for a kilogram (this is for the meat slurry shrimp product). The high cost can be attributed to the cell culture media that is currently sourced from pharma companies (likely a fetal bovine serum), which Shiok is working to replace with their own custom developed animal free formula. To develop a more structured shrimp product, Shiok is looking at mixing the shrimp with plant based collagen such as algae, seaweed or cactus, to create 3D scaffolding for the tissue to grow on. 3D Bioprinting Solutions is a Biotechnology laboratory founded by INVITRO, the largest private medical company in Russia. The laboratory develops and produces bioprinters and materials for 3D bioprinting, and also develops innovative technologies in the field of biofabrication. Bioprinters created in this laboratory could be used for 3D printing of cell based meat products. BayMedica is developing a proprietary cannabinoid biosynthetic manufacturing platform using yeast strains. The company is working on producing natural pharmaceutical-grade cannabinoids, including CBC, CBD and CBG as well as novel cannabinoid analogs for life science, pharmaceutical, nutraceutical, cosmetic and animal health applications. Cellibre is developing cell cultured cannabinoids through a set of host organisms (beyond the standard bacteria, yeast and algae) that are well suited to produce cannabinoids as part of their innate infrastructure. The company aims to be a contract manufacturer and supplier to cannabis companies as well as the CPG and Pharma industries. Most cannabis biosynthesis occurs through a specific host organism - bacteria, yeast, or algae. The host organism must be specifically engineered to produce cannabinoids. Each company is therefore creating a custom host organism, which can be patentable. The host organism is incredibly important to the overall process of cannabis biosynthesis because it determines how much engineering needs to occur to create a fully functioning synthesis factory. CUBIQ FOODS is the first European producer of cell-based fat. The company plans to develop and commercialize cell based fat to enhance the flavor of food and add essential fatty acids (omega-3) to food products. VOW is developing cell based kangaroo meat. In 2019, the company unveiled the first prototype, which was a few grams of kangaroo meat made into steamed dumplings. VOW is the first company we have seen taking a unique approach to cellular agriculture by cultivating species of meat not commonly consumed. Avant Meats is developing cell cultured fish maw (aka dried fish bladder), a delicacy in traditional Chinese cuisine. Fish maw is typically sourced from either the Chinese Bahaba (giant yellow croaker) or the Totoaba, both of which are on the brink of extinction due to such high demand for fish maw. Avant Meats will source cells from the Chinese Bahaba fish. Avant Meats has an advantage amongst cell based meat companies because they are focusing on solely producing the bladder, which is a more simple texture to produce compared to a whole meat cut. Further, fish maw is a very high value item — the retail price of Totoaba maw on the black Chinese market has been recently quoted up to USD 46 per gram in China. Craveri has extensive research experience in bioengineering cell types (keratinocytes, chondrocytes, cornea, etc) and has already created prototypes of muscle fiber rings that can be formed into a burger or meatball. They are currently working on culturing other cell types (connective tissue cells, fat cells, vascular cells) in order to combine them with the fibers and reach a product with the same texture, consistency and flavor then traditional meat. The company is working with local manufacturers to create scaled up bioreactors and once they acquire a big enough bioreactor, BIFE says they will be ready for commercial production. BlueNalu is developing a unique solution of vitamins, salts, lipids, sugars, plant proteins and amino acids (cell culture medium) that will also contain an animal free serum to efficiently cultivate fish muscle, connective tissue, and fat cells. At commercial scale, the cells will grow inside of a bioreactor with this cell culture medium. Thereafter, the cells will be placed in a centrifuge that separates them from excess materials by spinning rapidly. Lastly, the concentration of cells will be mixed with a nutritious liquid called bio-ink and then 3-D printed into the desired shape. The entire cell to edible fish process is expected to take two months. According to a company press release, BlueNalu has a goal to build 150,000 sq/ft manufacturing facilities in cities around the world to manufacture cell based seafood to meet the demands of 10 million nearby residents. Each 150,000 sq/ft facility shall produce between 9-18 million pounds of finished seafood products per year, or 36-72 million seafood fillets per year. BlueNalu's plans to break ground on its first production facility in 2025. In the immediate future, the company is optimizing the process on smaller scales with the target of a market launch in 2023. Bond Pet Foods is developing cell cultured proteins to be incorporated into pet food products. Instead of tissue engineering, the company uses DNA from a heritage hen as the blueprint for protein development. Unlike Tissue Engineering, Bond Pet Foods uses recombinant protein technology, meaning they are inserting animal muscle protein genes into microbes like yeast and then fermenting the engineered yeast cells. Finless Foods is developing cell based fish and seafood with its immediate focus on cultivating bluefin tuna cells. Bluefin tuna is one of the most expensive and overfished varieties of fish on the market and contains high levels of mercury. Finless plans to launch with a bluefin tuna sushi that is a ground product rather than a whole fillet of fish. JUST inc is based in San Francisco, California where the company makes plant based eggs, mayo, dressing and cookie dough. In 2018, JUST stated they would be entering into the cell based meat space starting with the production of cell cultured chicken nuggets and eventually moving into the production of cell cultured Wagyu beef. In November 2019, JUST announced the company would have a small scale launch of their cell based chicken nuggets that would cost $50 PER nugget. The nuggets will be primarily cell based chicken blended with a small amount of JUST proprietary mung bean protein isolate. As of December 2019, JUST is working with regulators to launch their nugget in several undisclosed countries. Mission Barns is a cell based tech company focused on producing flavor in the form of cell cultured fat. The company is working on developing bacon and duck fat working exclusively with fat cells as opposed to muscle cells that make up the bulk of animal tissue. Mission Barns was started by Eitan Fischer, former director of cellular agriculture at JUST and David Bowman, former researcher at JUST. New Age Meats is based in San Francisco, California where the company uses automation & data science to develop cell-cultured meat. New Age is currently working on developing pork sausage. The company released their first sausage prototype in September 2018, which cost $2600 to produce and was only 10% cultured pig cells (the remaining 90% was plant based). The company used fetal bovine serum to make these cultured pig cells, which they are currently working to replace. To reduce production costs and develop a viable growth medium, New Age is focusing on automated data collection. Wild Earth uses cellular fermentation to cultivate Koji, a high protein fungus that the company blends into pet treats and food. Wild Earth treats are currently on the market being sold online, at select brick-and-mortar retail stores, and wholesale to pet food retailers. Koji, the star ingredient in Wild Earth's pet food formula is very efficient to grow and scale and requires significantly fewer resources than meat. Wild Type is developing cell cultured salmon, which the company debuted during a tasting in June 2019. Just over a pound of cell based salmon was produced for the tasting, which reportedly took three and a half weeks to grow and cost an estimated $200 for 1 small serving (a single spicy salmon sushi roll). Wild Type plans to start with the introduction of smaller quantities of minced salmon where the meat is mixed with sauce. From there, they are targeting lox for bagels, and eventually, salmon filets. The company is aiming to produce full slabs of lab-grown salmon at a competitive retail cost of $7 to $8 per pound. Aleph's technology enables the growth of four types of animal cells including muscle fibers, blood vessels, fat, and connective tissue. This ability to grow all four types of cells that make up a steak, provide Aleph Farms a unique advantage versus other companies just focusing on a single cell type like muscle or fat exclusively. The company has also developed a custom animal free growth medium that contains many of the same nutrients and vitamins that are found inside a cow's body.

Autoclave

Piece of equipment used to sterilize articles by way of steam under pressure and/or dry heat Used in bio labs and medical applications

Rhizomucor miehei

Rhizomucor miehei is a species of fungus. It is commercially used to produce enzymes which can be used to produce a microbial rennet to curd milk and produce cheese. It is also used to produce lipases for interesterification of fats.

Population II stars

Stars poor in atoms heavier than helium; relatively old stars nearly always found in the halo, globular clusters, or the central bulge.

DNA Computers

Storing data in strand of DNA has one significant drawback: it's slow. Unlike computer chips, which communicate at nearly the speed of light using electrons, DNA data storage relies on physically moving molecules around. For this reason, we shouldn't expect to see DNA hard drives at your local computer store in the near future, Ceze says. Instead, he envisions using DNA data storage to preserve massive data archives, such as those used by Facebook and cloud storage services, where speed is not as crucial.

proper motion

The rate at which a star moves across the sky, measured in arc seconds per year

Tofu

Tofu, also known as bean curd, is a food prepared by coagulating soy milk and then pressing the resulting curds into solid white blocks of varying softness; it can be silken, soft, firm, or extra firm. Beyond these broad categories, there are many varieties of tofu. curd made from mashed soybeans, used chiefly in Asian and vegetarian cooking.

Kepler-1649c

Very little is known of Kepler-1649c's climate.[3] It receives fully 75% of the light from its host star that Earth receives from the Sun; therefore, depending on the atmosphere, its surface temperature may be similar enough to the temperature of the Earth that liquid water may be present.[2] It is unclear what the composition of Kepler-1649c's atmosphere is. 300 light-years from Earth The exoplanet was identified as a rocky planet by NASA[5] and is very similar to Earth in terms of size, with a radius 1.06 times that of Earth.[3][6] Kepler-1649c takes only 19.5 Earth days to orbit its host star Kepler-1649, an M-Type red dwarf.[7] It orbits within the habitable zone of its star system.

What makes traffic signs so reflective?

What you want instead is a reflector that reflects light right back where it came from. This is called "retroreflection". There are a number of ways to achieve retroreflection, but one common one is using a glass bead whose angles of refraction are carefully set up: Note that this works from most angles, not just straight on to the reflecting coat. So all you have to do is mix the beads in to your paint, or mix it in with the polymer sheet for making tape, and you get a highly retroreflective surface. Some of the beads won't be angled properly, but that's OK, since many will, and a large amount of light is reflected back at the driver of the car. http://www.rema.org.uk/pub/pdf/history-retroreflective-materials.pdf

flibbertigibbet

a frivolous, flighty, or excessively talkative person A flibbertigibbet is a very silly chatterbox. If your teacher calls you a flibbertigibbet, she clearly doesn't think you're a serious or scholarly person.

metallophilic

attraction between metal ions

extragalactic

outside or beyond a galaxy

porcine

pertaining to or resembling a pig

timbre (tamber)

the character or quality of a musical sound or voice as distinct from its pitch and intensity.

There is a branch of mathematics focused solely on knot theory. The literal tying of knots. This could have serious implications for protein folding.

Knot theory is a subject in mathematics where one studies what is known as the placement problem, or the embedding of one topological space into another. The simplest form of knot theory involves the embedding of the unit circle into three-dimensional space. Paper on knot theory and protein folding: https://sci-hub.tw/https://link.springer.com/article/10.1007/s00285-011-0488-3 https://www.youtube.com/watch?v=aqyyhhnGraw&feature=youtu.be&t=50

What is lab grown non-meat?

Lab grown non-meats including milk, eggs, gelatin, heme, flavors, and sweeteners are made using a different process than cell based meat. Lab grown foods (non-meat) are made through a process called precision fermentation. The process begins with a DNA sequence of the intended molecule. Advancements in DNA sequencing technology have made access to DNA quick and inexpensive. A bacteria or yeast cell aka a microorganism is modified; scientists insert the DNA sequence into the modified microorganism. The modified microorganism is placed into a fermentation tank where the cells multiply and proteins are formed. The heme ingredient in Impossible Foods plant-based meat is made using precision fermentation.

The Amazon represents over half of the planet's remaining rainforests, and comprises the largest and most biodiverse tract of tropical rainforest in the world, with an estimated 390 billion individual trees divided into 16,000 species.

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diameter of milky way

105,700 light years...

Geodesic dome

A geodesic dome is a hemispherical thin-shell structure based on a geodesic polyhedron. The triangular elements of the dome are structurally rigid and distribute the structural stress throughout the structure, making geodesic domes able to withstand very heavy loads for their size.

hubbles constant

A measure of the rate of expansion of the Universe, the average value of the apparent velocity of recession divided by distance, about 73 km/s/Mpc. The most precise measurements of the Hubble constant, made using the Hubble, Spitzer, and WMAP space telescopes yield a value for H of about 70 km/s/Mpc with an uncertainty of just a few percent. This means that a galaxy at a distance of 1 Mpc from the Milky Way is receding from us at a rate of 70 km/s, a galaxy 2 Mpc away is receding at 140 km/s, and so on. This relation between apparent velocity of recession and distance is known as the Hubble law, and the slope of the line is known as the Hubble constant, symbolized by H.

Neutron stars

A neutron star contains a little more than 1 solar mass compressed to a radius of about 10 km. Its density is so high that the matter is stable only as a fluid of pure neutrons.

Photomultiplier tube

A photomultiplier tube, useful for light detection of very weak signals, is a photoemissive device in which the absorption of a photon results in the emission of an electron. These detectors work by amplifying the electrons generated by a photocathode exposed to a photon flux Photomultiplier tubes (photomultipliers or PMTs for short), members of the class of vacuum tubes, and more specifically vacuum phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. These detectors multiply the current produced by incident light by as much as 100 million times or 10^8 (i.e., 160 dB)[1], in multiple dynode stages, enabling (for example) individual photons to be detected when the incident flux of light is low.

compact object

A star that has collapsed to form a white dwarf, neutron star, or black hole. One of the three final states of stellar evolution, which generates no nuclear energy and is much smaller and denser than a normal star.

Erg

An erg (also sand sea or dune sea, or sand sheet if it lacks dunes) is a broad, flat area of desert covered with wind-swept sand with little or no vegetative cover. The depth of sand in ergs varies widely around the world, ranging from only a few centimeters deep in the Selima Sand Sheet of Southern Egypt, to approximately 1 m (3.3 ft) in the Simpson Desert, and 21-43 m (69-141 ft) in the Sahara.

Theoretical Prediction of Neutron Stars

The subatomic particles called neutrons were discovered in a laboratory in 1932, and physicists quickly realized that because neutrons spin much like electrons, a gas of neutrons could become degenerate and therefore nearly incompressible. Just 2 years later, in 1934, two astronomers, Walter Baade and Fritz Zwicky, suggested that some of the most luminous novae in the historical record were not regular novae but were caused by the collapse plus explosion of a massive star in a cataclysm they named a "super-nova." If the collapsing core is more massive than the Chandrasekhar limit of 1.4 solar masses, then the weight is too great to be supported by degenerate electron pressure, and the core cannot become a stable white dwarf. The collapse would force protons to combine with electrons and become neutrons. The envelope of the star would be blasted away in a supernova explosion, and the core of the star would be left behind as a small, tremendously dense sphere of neutrons that Zwicky called a "neutron star." Mathematical models predict that a neutron star will be only 10 or so kilometers in radius (Figure 11-12) and will have a density of almost 10^15 g/cm^3 . That is roughly the density of atomic nuclei, and you can think of a neutron star as matter with all of the empty space squeezed out of it. On Earth, a sugar-cube-sized lump of this material would weigh more than a billion tons, the mass of a small mountain. Simple physics, the physics you have used in previous chapters to understand normal stars, predicts that neutron stars should (1) spin rapidly, perhaps 100 to 1000 rotations per second; (2) be hot, with surface temperatures of millions of degrees Kelvin; and (3) have strong magnetic fields, up to a trillion times stronger than the Sun's or Earth's magnetic fields. For example, the collapse of a massive star's core would greatly increase its spin rate by conservation of angular momentum. Other processes during core collapse should create high temperature and magnetic field strength. Despite their high temperature, neutron stars should be difficult to detect because of their tiny size. What is the maximum mass for a stable neutron star? In other words, is there an upper limit to the mass of neutron stars like the Chandrasekhar limit that defines the maximum mass of a white dwarf star? That is difficult to answer, because physicists don't know enough about the properties of pure neutron material. It can't be made in a laboratory, and theoretical calculations in this case are very difficult. The most widely accepted results suggest that a neutron star must be less massive than 2 to 3 solar masses. An object more massive than that can't be supported by degenerate neutron pressure, so it would collapse, presumably becoming a black hole. What size stars will end their lives with supernova explosions that leave behind neutron star corpses? Theoretical calculations suggest that stars that begin life on the main sequence with 8 to about 15 solar masses will end up as neutron stars. Stars more massive than about 15 solar masses are expected to form black holes when they die.

Fermentation

Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of respiration. In the context of food production, it may more broadly refer to any process in which the activity of microorganisms brings about a desirable change to a foodstuff or beverage.[1] The science of fermentation is known as zymology. In microorganisms, fermentation is the primary means of producing adenosine triphosphate (ATP) by the degradation of organic nutrients anaerobically.[2] Humans have used fermentation to produce foodstuffs and beverages since the Neolithic age. For example, fermentation is used for preservation in a process that produces lactic acid found in such sour foods as pickled cucumbers, kombucha, kimchi, and yogurt, as well as for producing alcoholic beverages such as wine and beer. Fermentation also occurs within the gastrointestinal tracts of all animals, including humans.[3] Along with photosynthesis and aerobic respiration, fermentation is a way of extracting energy from molecules, but it is the only one common to all bacteria and eukaryotes. It is therefore considered the oldest metabolic pathway, suitable for an environment that does not yet have oxygen.[5]:389 Yeast, a form of fungus, occurs in almost any environment capable of supporting microbes, from the skins of fruits to the guts of insects and mammals and the deep ocean, and they harvest sugar-rich materials to produce ethanol and carbon dioxide.[6][7] The basic mechanism for fermentation remains present in all cells of higher organisms. Mammalian muscle carries out the fermentation that occurs during periods of intense exercise where oxygen supply becomes limited, resulting in the creation of lactic acid.[8]:63 In invertebrates, fermentation also produces succinate and alanine.[9]:141 Fermentative bacteria play an essential role in the production of methane in habitats ranging from the rumens of cattle to sewage digesters and freshwater sediments. They produce hydrogen, carbon dioxide, formate and acetate and carboxylic acids; and then consortia of microbes convert the carbon dioxide and acetate to methane. Acetogenic bacteria oxidize the acids, obtaining more acetate and either hydrogen or formate. Finally, methanogens (which are in the domain Archea) convert acetate to methane.[10] Fermentation reacts NADH with an endogenous, organic electron acceptor.[2] Usually this is pyruvate formed from sugar through glycolysis. The reaction produces NAD+ and an organic product, typical examples being ethanol, lactic acid, carbon dioxide, and hydrogen gas (H2). However, more exotic compounds can be produced by fermentation, such as butyric acid and acetone. Fermentation products contain chemical energy (they are not fully oxidized), but are considered waste products, since they cannot be metabolized further without the use of oxygen. Although yeast carries out the fermentation in the production of ethanol in beers, wines, and other alcoholic drinks, this is not the only possible agent: bacteria carry out the fermentation in the production of xanthan gum.

disingenuous

Insincere, not genuine not candid or sincere, typically by pretending that one knows less about something than one really does.

We've arranged a global civilization in which most crucial elements profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces. - Carl Sagan

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Whats next after whats next?

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salt

An ionic compound made from the neutralization of an acid with a base. Salt, in chemistry, substance produced by the reaction of an acid with a base. A salt consists of the positive ion (cation) of a base and the negative ion (anion) of an acid.

"Science is more than a body of knowledge; it is a way of thinking. I have a foreboding of an America in my children's or grandchildren's time—when the United States is a service and information economy; when nearly all the key manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what's true, we slide, almost without noticing, back into superstition and darkness." -Carl Sagan

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"The best way to communicate from one human being to another is through story."

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As more pulsars were found, astronomers argued over their nature. The pulses, which typically last only about 0.001 second, gave astronomers an important clue. The pulse length places an upper limit on the size of the object producing the pulse. This is a very important principle in astronomy—an object cannot change its brightness significantly in an interval shorter than the time light takes to cross its diameter. If pulses from pulsars are no longer than 0.001 second, then the objects cannot be larger than 0.001 light-second, or 300 km (200 miles) in diameter, smaller than white dwarfs, which makes neutron stars the only reasonable explanation. The missing link between pulsars and neutron stars was found in late 1968, when astronomers discovered a pulsar at the heart of the Crab Nebula (see Figure 11-8). The Crab Nebula is a supernova remnant, which agrees nicely with Zwicky and Baade's prediction that some supernovae should produce a neutron star. The short pulses and the discovery of the pulsar in the Crab Nebula are strong evidence that pulsars are neutron stars.

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When Freeman Dyson passed away in February at the age of 96, the world lost one of its most versatile scientists and astute humanists. Trained as a mathematician, Dyson had an appetite for number theory, but his most famous achievement came early as a theoretical physicist, laying out the architecture of modern particle physics. He then moved into the design of nuclear reactors, nuclear-powered space travel, astronomy, astrobiology, climate change and futurism, all while being "a wise observer of the human scene." He described himself as a frog, not a bird, as he enjoyed jumping from pool to pool, studying their details deeply in the mud. The bird's-eye perspective was not for him, and he had a lifelong suspicion of grand unified theories. Together, they set their minds on resolving the mysteries of quantum theory. Among them was Richard Feynman, the quirkiest and most brilliant of the bunch. Dyson described him as "half genius and half buffoon." They made an immediate and lasting connection.

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What is needed for growing cultured meat?

1. Muscle Pre-Cursor Cells (starting cells taken from the animal to replicate) 2. Scaffold (a supportive structure for the cells to grow) 3. Bioreactor (an aseptic temperature and PH controlled environment i.e. a home) 4. Cell Culture Media (a growth medium i.e. food) Muscle pre-cursor cells are starter cells taken through a biopsy from an animal and used to cultivate tissues. Muscle pre-cursor cells have a limited lifespan and will regularly need replenishing in the form of another tissue biopsy from an animal. Some are using cow umbilical cord stem cells. Scaffolds provide structure for cells to replicate and enables the growth of a variety of structures of meat such as steaks or chicken breasts. There are materials that can be used as scaffolds — all containing a set of design requirements: biocompatibility, biodegradability, elasticity, pore size, geometry, tensile strength. Some examples of scaffold materials are silk, collagen, gellan gum and alginate. A cell based tech scaffold is not a physical structure or stage like those used for construction. A bioreactor is an aseptic environment with a controlled temperature and PH that supports cell proliferation. A bioreactor enables cell based meat to be produced on a large scale and a clean, stable environment for the cells to grow. Cell culture media contains nutrients (both organic and inorganic): vitamins, salts, O2 and CO2 gas phases, serum proteins, carbohydrates, cofactors. Serum proteins are an integral component to cell culture media. Serum provides various growth factors and hormones involved in growth promotion and specialized cell function. The most common serum on the market is fetal bovine serum: blood taken from an unborn calf whose mother was slaughtered. Therefore reliant on the current system of slaughterhouse agriculture and contrary to the point of cell based meat production. There are companies working on artificial cell culture media that do not contain fetal bovine serum, but it is still not clear as to whether these serums can efficiently promote cell growth.

how many satellite galaxies orbit the milky way?

In particular, the Milky Way is currently known to host 59 satellite galaxies (see satellite galaxies of the Milky Way), however two of these satellites known as the Large Magellanic Cloud and Small Magellanic Cloud have been observable in the Southern Hemisphere with the unaided eye since ancient times. A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and luminous host galaxy (also known as the primary galaxy).[1] Satellite galaxies and their constituents are bound to their host galaxy, in the same way that planets within our own solar system are gravitationally bound to the Sun.[2] While most satellite galaxies are dwarf galaxies, satellite galaxies of large galaxy clusters can be much more massive.[3] The Milky Way is orbited by 59 satellite galaxies, the largest of which is the Large Magellanic Cloud.

Degenerate matter

A normal star is supported by energy flowing outward from its core, but a white dwarf cannot generate energy by nuclear fusion. It has exhausted its hydrogen and helium fuel and produced carbon and oxygen. As the star contracts into a white dwarf, it converts gravitational energy into thermal energy, and its interior becomes very hot, but it cannot get hot enough to fuse carbon into heavier elements. The contraction of a white dwarf compresses the gases in its interior to such high densities that quantum mechanical laws become important, and the electrons in the gas cannot get closer together. Such a gas is termed degenerate matter, and it takes on two properties that are important in understanding the structure and evolution of dying stars. A degenerate gas is millions of times harder to compress than solid steel, and the pressure in the gas no longer depends on the temperature. Unlike a normal star, which is supported by ordinary gas pressure, a white dwarf is supported against its own gravity by the resistance to compression of a degenerate gas. Clearly, a white dwarf is not a true star. It generates no nuclear energy, is almost completely degenerate matter, and, except for a thin layer at its surface, contains no gas. Instead of calling a white dwarf a "star," you could call it a compact object. Later sections of this chapter discuss two other types of compact objects, neutron stars and black holes.

Sanger sequencing

A procedure in which chemical termination of daughter strands help in determining the DNA sequence. Sanger sequencing is a method of DNA sequencing based on the selective incorporation of chain-terminating dideoxynucleotides by DNA polymerase during in vitro DNA replication.

reverse merger

A reverse takeover or reverse merger takeover is the acquisition of a public company by a private company so that the private company can bypass the lengthy and complex process of going public. The transaction typically requires reorganization of capitalization of the acquiring company

tangential flow filtration

A type of ultrafiltration where small molecules diffuse out of a solution as they pass by a filtering membrane, resulting in a solution with a higher concentration of the molecule of interest- also called TFF. Allows the filter to self clean. In conventional filters the flow moves perpendicular to the filter. With this, it moves tangentially (horizontal). This allows the media to flow and be recirculated as long as it needs to until all of the desired material permeates through.

Biting on aluminum foil can be painful. Why?

Biting on aluminum foil can be painful and is usually noticed if you have metal in your mouth from dental work (e.g. fillings, crowns). Basically, when you bite on foil, you set up a battery in your mouth and the electrical current stimulates nerve endings in your tooth. Here is what happens: - pressure from biting brings two dissimilar metals (aluminum foil, mercury in fillings or gold in crowns) in contact in a moist, salty environment (saliva) - the two metals have an electrochemical potential difference or voltage across them - electrons flow from the foil into the tooth (i.e. electrical current) - the current gets conducted into the tooth's root, usually by the filling or crown - the current sets off a nerve impulse in the root's nerve - the nerve impulse is sent to the brain - the brain interprets the impulse as pain The production of electric current between two metals in contact is called the voltaic effect after Alessandro Volta, who discovered it. Early batteries were made by stacking metal discs together in a pile called a voltaic pile.

Bacteriophage

A virus that infects bacteria Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. MS2) and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm. Bacteriophages are among the most common and diverse entities in the biosphere.[1] Bacteriophages are ubiquitous viruses, found wherever bacteria exist. It is estimated there are more than 10^31 bacteriophages on the planet, more than every other organism on Earth, including bacteria, combined.[2] One of the densest natural sources for phages and other viruses is seawater, where up to 9x10^8 virions per millilitre have been found in microbial mats at the surface,[3] and up to 70% of marine bacteria may be infected by phages.[4] Bacteriophages may have a lytic cycle or a lysogenic cycle. With lytic phages such as the T4 phage, bacterial cells are broken open (lysed) and destroyed after immediate replication of the virion. As soon as the cell is destroyed, the phage progeny can find new hosts to infect. Lytic phages are more suitable for phage therapy. Some lytic phages undergo a phenomenon known as lysis inhibition, where completed phage progeny will not immediately lyse out of the cell if extracellular phage concentrations are high. This mechanism is not identical to that of temperate phage going dormant and usually, is temporary. Bacterial cells are protected by a cell wall of polysaccharides, which are important virulence factors protecting bacterial cells against both immune host defenses and antibiotics.[41] To enter a host cell, bacteriophages attach to specific receptors on the surface of bacteria, including lipopolysaccharides, teichoic acids, proteins, or even flagella. This specificity means a bacteriophage can infect only certain bacteria bearing receptors to which they can bind, which in turn, determines the phage's host range. Polysaccharide-degrading enzymes, like endolysins are virion-associated proteins to enzymatically degrade the capsular outer layer of their hosts, at the initial step of a tightly programmed phage infection process. Host growth conditions also influence the ability of the phage to attach and invade them.[42] As phage virions do not move independently, they must rely on random encounters with the correct receptors when in solution, such as blood, lymphatic circulation, irrigation, soil water, etc.

how many scientific papers are published each year?

According to research from the University of Ottawa, in 2009 we passed the 50 million mark in terms of the total number of science papers published since 1665, and approximately 2.5 million new scientific papers are published each year

Adipocyte

Adipocytes, also known as lipocytes and fat cells, are the cells that primarily compose adipose tissue, specialized in storing energy as fat. Adipocytes are derived from mesenchymal stem cells which give rise to adipocytes through adipogenesis. In cell culture, adipocytes can also form osteoblasts, myocytes and other cell types. There are two types of adipose tissue, white adipose tissue (WAT) and brown adipose tissue (BAT), which are also known as white and brown fat, respectively, and comprise two types of fat cells.

Spectrophotometry

An analytical method for identifying a substance by its selective absorption of different wavelengths of light. In chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength.[2] It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared, but does not cover time-resolved spectroscopic techniques. An example of an experiment in which spectrophotometry is used is the determination of the equilibrium constant of a solution. A certain chemical reaction within a solution may occur in a forward and reverse direction, where reactants form products and products break down into reactants. At some point, this chemical reaction will reach a point of balance called an equilibrium point. In order to determine the respective concentrations of reactants and products at this point, the light transmittance of the solution can be tested using spectrophotometry. The amount of light that passes through the solution is indicative of the concentration of certain chemicals that do not allow light to pass through.

Supernova remnant

An expanding shell of gas ejected at high speeds by a supernova explosion. Supernova remnants are often visible as diffuse gaseous nebulae usually with a shell-like structure. Many resemble "bubbles" in space. Most are not in the visible light region. Supernova remnants look quite delicate and do not survive very long—a few tens of thousands of years— before they gradually mix with the interstellar medium and vanish. The Crab Nebula is a young remnant, only about 960 years old and about 9 light-years in diameter. Older remnants can be larger. Some supernova remnants are visible only at radio and X-ray wavelengths. They have become too tenuous to emit detectable light, but the collision of the expanding hot gas with the interstellar medium can generate radio and X-ray radiation. You learned in Chapter 10 Section 10-4b that the compression of the interstellar medium by expanding supernova remnants can also trigger star formation. Gravity always wins. However a star lives, theory predicts it must eventually die and leave behind one of three types of final remains—a white dwarf, neutron star, or black hole. These compact objects are small monuments to the power of gravity. Almost all of the gravitational potential energy available has been squeezed out of compact objects, and you find them in their final, high-density states.

Planetary nebula

An expanding shell of gas ejected from a medium-mass star during the latter stages of its evolution. When a medium-mass star like the Sun becomes a distended giant, its atmosphere becomes cool and consequently more opaque. Light has to push against it to escape. At the same time, the fusion shells become thin and unstable, and they begin to flare, which pushes the atmosphere outward. An aging giant can expel its outer atmosphere in repeated surges to form one of the most beautiful objects in astronomy, a planetary nebula, so called because the first ones discovered looked like the greenish-blue disks of planets such as Uranus or Neptune. In fact, a planetary nebula has nothing to do with a planet. It is composed of ionized gases expelled by a dying star, like the nebulae in Figure 11-3.

Anaerobic digestion

Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen.[1] The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion. Many microorganisms affect anaerobic digestion, including acetic acid-forming bacteria (acetogens) and methane-forming archaea (methanogens). These organisms promote a number of chemical processes in converting the biomass to biogas.[14] Gaseous oxygen is excluded from the reactions by physical containment. Anaerobes utilize electron acceptors from sources other than oxygen gas. These acceptors can be the organic material itself or may be supplied by inorganic oxides from within the input material. When the oxygen source in an anaerobic system is derived from the organic material itself, the 'intermediate' end products are primarily alcohols, aldehydes, and organic acids, plus carbon dioxide. In the presence of specialised methanogens, the intermediates are converted to the 'final' end products of methane, carbon dioxide, and trace levels of hydrogen sulfide.[15] In an anaerobic system, the majority of the chemical energy contained within the starting material is released by methanogenic bacteria as methane.[16] The four key stages of anaerobic digestion involve hydrolysis, acidogenesis, acetogenesis and methanogenesis.[18] The overall process can be described by the chemical reaction, where organic material such as glucose is biochemically digested into carbon dioxide (CO2) and methane (CH4) by the anaerobic microorganisms. Hydrolysis In most cases, biomass is made up of large organic polymers. For the bacteria in anaerobic digesters to access the energy potential of the material, these chains must first be broken down into their smaller constituent parts. These constituent parts, or monomers, such as sugars, are readily available to other bacteria. The process of breaking these chains and dissolving the smaller molecules into solution is called hydrolysis. Therefore, hydrolysis of these high-molecular-weight polymeric components is the necessary first step in anaerobic digestion.[19] Through hydrolysis the complex organic molecules are broken down into simple sugars, amino acids, and fatty acids. Acidogenesis The biological process of acidogenesis results in further breakdown of the remaining components by acidogenic (fermentative) bacteria. Here, VFAs are created, along with ammonia, carbon dioxide, and hydrogen sulfide, as well as other byproducts.[21] The process of acidogenesis is similar to the way milk sours. Acetogenesis The third stage of anaerobic digestion is acetogenesis. Here, simple molecules created through the acidogenesis phase are further digested by acetogens to produce largely acetic acid, as well as carbon dioxide and hydrogen.[22] Methanogenesis The terminal stage of anaerobic digestion is the biological process of methanogenesis. Here, methanogens use the intermediate products of the preceding stages and convert them into methane, carbon dioxide, and water. These components make up the majority of the biogas emitted from the system. Methanogenesis is sensitive to both high and low pHs and occurs between pH 6.5 and pH 8.[23] The remaining, indigestible material the microbes cannot use and any dead bacterial remains constitute the digestate.

Aramid

Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, marine hull reinforcement, and as an asbestos substitute.[1] The name is a portmanteau of "aromatic polyamide". The chain molecules in the fibers are highly oriented along the fiber axis. As a result, a higher proportion of the chemical bond contributes more to fiber strength than in many other synthetic fibers. Aramides have a very high melting point (>500 °C) The most well-known aramids (Kevlar, Twaron, Nomex, New Star and Teijinconex) are AABB polymers.

Koji

Aspergillus oryzae, also known as kōji, is a filamentous fungus used in East Asia to ferment soybeans for making soy sauce and fermented bean paste, and also to saccharify rice, other grains, and potatoes in the making of alcoholic beverages such as sake and shōchū.

Pulsar planets

Because a pulsar's period is so precise, astronomers can detect tiny variations by comparison with atomic clocks. When astronomers checked pulsar PSR B1257+12, they found variations in the period of pulsation (Figure 11-16a) analogous to the variations caused by the orbital motion of the binary pulsar but much smaller. When these variations were interpreted as Doppler shifts, it became evident that the pulsar was being orbited by at least two objects with planet-like masses of about 3 to 4 Earth masses. The gravitational tugs of the planets make the pulsar wobble about the center of mass of the system by about 800 km, and that produces the tiny changes that are observed (Figure 11-16b). Astronomers wonder how a neutron star can have planets. The inner three planets that orbit PSR B1257+12 are closer to the pulsar than Venus is to the Sun. Any planets that orbit a star would be lost or vaporized when the star exploded. Furthermore, a star about to explode as a supernova would be a large giant or a supergiant, and planets only a few AU distant would be inside such a large star and could not survive. It seems more likely that these planets are the remains of a stellar companion that was devoured by the neutron star. In fact, PSR B1257+12 is very fast (161 pulses per second), suggesting that it was spun up in a binary system.

Some Animals Have No Microbiome. Here's What That Tells Us.

But when Sanders turned to the rest of the ants — about two-thirds of the different colonies and species he had collected — he was surprised to find that "you would be hard-pressed to find any cells in the gut that you could readily identify as bacteria," he said. Food, debris, the cells of the insects' gut lining — all were present. Microbes that might be engaged in the symbiotic relationships we take for granted — not so much. Some ants have microbiome, some don't. Deepa Agashe, an ecologist and evolutionary biologist at the National Center for Biological Sciences in Bangalore, India, saw something similar in insects that her team collected from several locations near the greenery of their campus. The microbes they found in dragonflies and butterflies strongly correlated with the insects' diets rather than with a particular insect species or developmental stage. The vast majority of the dragonflies' bacterial communities seemed to have come together by chance. "Most of the bacteria were just there because they got there," Agashe said. The insects "do not seem to be selecting for particular species of bacteria or a particular kind of bacteria." But maybe it shouldn't be so surprising. As the scientists realized, when microbiomes are present, they're often found in specific tissues — and they involve specific bacteria that influence specific traits at specific times. The bobtail squid, for example, has a symbiosis that's limited to one species of luminous bacteria, which is sequestered in a single light-producing organ while the squid's gut and skin remain microbe-free. Adult honeybees have important relationships with their bacteria, but the larvae don't. "If you think about it, there's lots of reasons not to have an established microbiome," Agashe said. "It's actually not surprising that there are animals that have gone a different route. ... But the key thing is, we don't know why" — what factors lead to and enable the formation and maintenance of a microbiome, and conversely, what factors might prevent those relationships.

Pitch-based carbon fiber

Carbon fiber is often time produced using two main methods: through the use of Polyacrylonitrile (PAN) and from pitch.[1][2][3] Pitch is a viscoelastic material that is composed of aromatic hydrocarbons. Pitch is produced via the distillation of carbon-based materials, such as plants, crude oil, and coal.[1][2][3] Pitch is isotropic, but can be made anisotropic through the use of heat treatments. However, the most important in carbon fiber production is mesophase pitch due to the ability to melt spin anisotropic mesophase pitch without filament breakage. There are four main steps in the production of carbon fiber from pitch 1) melt spinning 2) oxidization/precarbonization 3) carbonization and 4) graphitization. 1) Melt spinning is the method of forming fibers through the rapid cooling of a melt; due to the fast rates of cooling, the mesophase pitch is able to become highly oriented. Mesophase pitch can be melt spun, but because of its flow characteristics the process can be difficult.[7] The viscosity of mesophase pitch is more sensitive to temperature than other melt-spun materials. Therefore, during the creation of pitch based fibers the temperature and heat transfer rate must be carefully controlled. 2) Oxidization/Precarbonization is used in order to cross-link the fibers to the point where they cannot be melted or fused together.[1] This step is extremely important because it produces fibers that are stable at the high temperatures of carbonization and graphitization; otherwise, the fibers would fail in those steps of the process. 3) Carbonization is the process removing all nonorganic elements. In the case of carbon fibers, all elements except for carbon are removed. This is achieved by heating the fibers to high temperatures in an environment without oxygen.[6][8] This step removes all impurities from the fibers and leaves crystalline carbon structures. These structures are mostly hexagonal in shape and are composed of entirely carbon. 4) Graphitization is the process of treating the fibers at high temperatures in order to improve the alignment and orientation of the crystalline regions along the fiber direction [1,8]. Having the crystalline regions aligned, stacked, and oriented along the fiber direction increases the overall strength of the carbon fiber. The high strength of carbon fiber can be attributed to these four main processes. Having high levels of crystalline regions allows the fibers to withstand high levels of stress. These crystalline regions are formed via the melt spinning process; the crystals are stiff areas that do not deform when an external stress is applied. Orienting and aligning these crystalline regions gives further strength to the fibers, specifically if the orientation is along the fiber axis. Carbonization and graphitization are the two processes responsible for this alignment of the crystalline regions. Pitch based carbon fiber is lower in strength than fiberglass; however, it has a very high elastic modulus.

Carbon fibers

Carbon fibers or carbon fibres (alternatively CF, graphite fiber or graphite fibre) are fibers about 5-10 micrometres in diameter and composed mostly of carbon atoms. Carbon fibers have several advantages including high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion. These properties have made carbon fiber very popular in aerospace, civil engineering, military, and motorsports, along with other competition sports. However, they are relatively expensive when compared with similar fibers, such as glass fibers or plastic fibers. To produce a carbon fiber, the carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber as the crystal alignment gives the fiber high strength-to-volume ratio (in other words, it is strong for its size). Several thousand carbon fibers are bundled together to form a tow, which may be used by itself or woven into a fabric. Image: carbon fiber (small) compared to human hair

DNA has a strong negative charge

DNA has a negative charge due to the negative charge of its phosphate component. The other two components of DNA consist of a 5-carbon sugar and a nitrogen base. The phosphate are found in the ribose-phosphate backbone of DNA.

Viral replication

DNA viruses all replicate in the nucleus (except poxvirus) All RNA viruses replicate in the cytoplasm (except influenza virus and retroviruses) Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm.[1] The virus replication occurs in seven stages, namely; Adsorption, Entry, Uncoating, Transcription / mRNA production, Synthesis of virus components, Virion assembly and Release (Liberation Stage). Adsorption It is the first step of viral replication. The virus attaches to the cell membrane of the host cell. It then injects its DNA or RNA into the host to initiate infection. In animal cells these viruses get into the cell through the process of endocytosis which works through fusing of the virus and fusing of the viral envelope with the cell membrane of the animal cell and in plant cell it enters through the process of pinocytosis which works on pinching of the viruses. Entry The cell membrane of the host cell invaginates the virus particle, enclosing it in a pinocytotic vacuole. This protects the cell from antibodies like in the case of the HIV virus. Uncoating Cell enzymes (from lysosomes) strip off the virus protein coat. This releases or renders accessible the virus nucleic acid or genome. Transcription / mRNA production For some RNA viruses, the infecting RNA produces messenger RNA (mRNA). This is translation of the genome into protein products. For others with negative stranded RNA and DNA, viruses are produced by transcription then translation. The mRNA is used to instruct the host cell to make virus components. The virus takes advantage of the existing cell structures to replicate itself. Synthesis of virus components The following components are manufactured by the virus through the host's existing organelles: Viral protein synthesis: virus mRNA is translated on cell ribosomes into two types of virus protein. Structural: the proteins which make up the virus particle are manufactured and assembled. Non - structural: not found in particle, mainly enzymes for virus genome replication. Viral nucleic acid synthesis (genome replication) new virus genome is synthesized, templates are either the parental genome or with single stranded nucleic acid genomes, newly formed complementary strands. By a virus called polymerate or replicate in some DNA viruses by a cell enzyme. This is done in rapidly dividing cells. Virion assembly A virion is simply an active or intact virus particle. In this stage, newly synthesized genome (nucleic acid), and proteins are assembled to form new virus particles. This may take place in the cell's nucleus, cytoplasm, or at plasma membrane for most developed viruses. Release (liberation stage) The viruses, now being mature are released by either sudden rupture of the cell, or gradual extrusion(budding) of enveloped viruses through the cell membrane. The new viruses may invade or attack other cells, or remain dormant in the cell. In the case of bacterial viruses, the release of progeny virions takes place by lysis of the infected bacterium. However, in the case of animal viruses, release usually occurs without cell lysis.

The future of the sun

Evolutionary models of the Sun suggest that it might survive as an energy-generating star for another 7 or 8 billion years. In about 6 billion years, it will exhaust the hydrogen in its core, leave the main sequence, begin burning hydrogen in a shell, and swell into a red giant star about 30 times its current radius. Later, helium fusion will ignite in the core and the Sun will become a horizontal branch star. After the helium fuel is exhausted in its core, helium fusion will begin in a shell, and the Sun will expand again. That second red giant version of the Sun will be about as large as the orbit of Earth. Before that, the Sun's increasing luminosity will certainly evaporate Earth's oceans, drive away the atmosphere, and even vaporize much of Earth's crust. Astronomers are still uncertain about some of the details, but computer models that include tidal effects predict that the expanding Sun eventually will engulf and destroy Mercury, Venus, and Earth. While it is a giant star, the Sun will have a strong wind and lose a substantial fraction of its mass into space. The atoms that were once in Earth will be part of the expanding nebula around the Sun. Your atoms will be part of that nebula. If the white dwarf remnant Sun becomes hot enough, it will ionize the expelled gas and light it (and you) up as a planetary nebula. Models of the Sun's evolution are not precise enough to predict whether its white dwarf remnant will become hot enough soon enough to light up its expelled gas and create a planetary nebula before that gas disperses. Whether the expelled gas lights up or not, it would include atoms that were once part of Earth. Some research also suggests that a star needs a close binary companion to speed up its spin in order to create a planetary nebula. The Sun, of course, has no close stellar companion. This is an area of active research, and there are as yet no firm conclusions. There is no danger that the Sun will explode as a nova; it has no binary companion (see the next section of this chapter). And, as you will see, the Sun is definitely not massive enough to die the violent supernova death of the most massive stars.

Oil Immersion Microscopy

Filling the air gap on a microscope with oil to improve visibility. In light microscopy, oil immersion is a technique used to increase the resolving power of a microscope. This is achieved by immersing both the objective lens and the specimen in a transparent oil of high refractive index, thereby increasing the numerical aperture of the objective lens.

foie gras

Foie gras is a specialty food product made of the liver of a duck or goose. By French law, foie gras is defined as the liver of a duck or goose fattened by force-feeding corn with a feeding tube, a process also known as gavage. In Spain and other countries, it is occasionally produced using natural feeding.

What's special about hypersonic speeds?

Hypersonics are conveniently defined as any speed above Mach 5, because around Mach 5 a lot of engineering problems change their form. At supersonic speeds, you can quite easily maintain subsonic combustion (a shock cone or ramp intake will do much of this, check Concorde's intakes which are well documented) for a conventional turbine-based engine. Your airframe will experience drag heating from skin friction, but this again can be solved using titanium, ceramics, carbon, etc. Flight controls can be conventional control surfaces, so long as you take into account things like aileron reversal. As we approach hypersonic velocities, all this starts to change. Subsonic combustion becomes impractical, it causes too much drag, so you need to either not intake oxygen (e.g. a rocket) or do your combustion supersonic (e.g. scramjet). Airframe heating is more intense, but that's manageable (orbital craft re-enter way, way faster than mach 5), what changes is that the leading edge is now exposed to reactive oxygen species (ROS), oxygen plasmas, atomic oxygen, ionised oxygen. Oxygen attacks metal just sat in the open, ROS are types of oxygen turned up to 11: Atomic oxygen can oxidise fluorides. Coming back from orbit, we can use disposable ablative heat shields, and large blunt-bodies to push the shock back. In flight we can't do this if we want to remain flying very long. Flight controls are different too. If you actuate an elevator, you lose your elevator and empennage, so your turn radius is extremely large. Hypersonic craft get their lift from inertia (ballistics) as much as from the air, and from the air it's less wings as much as lifting bodies. This is partly the sheer speed of oncoming air, and partly your enormous inertial momentum. You go in a straight line, which becomes a ballistic trajectory at hypersonic speeds, aerodynamic flight is a secondary concern. So in summary, hypersonics are where the engineering challenges change substantially, and it's conventionally accepted to be around mach 5 where those challenges are the primary ones.

INFJ

INFJ (introverted, intuitive, feeling, and judging) is one of the 16 personality types identified by the Myers-Briggs Type Indicator (MBTI). ... INFJs are usually reserved but highly sensitive to how others feel. They are typically idealistic, with high moral standards and a strong focus on the future. ive been attacked, arm the defences!

Crab Nebula

In the year 1054, Chinese astronomers saw a "guest star" appear in the constellation known in the Western tradition as Taurus the Bull. The star quickly became so bright it was visible in the daytime, and then, after a month, it slowly faded, taking almost 2 years to vanish from sight. When modern astronomers turned their telescopes to the location of the guest star, they found a peculiar nebula now known as the Crab Nebula for its many-legged shape. The Crab Nebula is clearly the remains of the supernova seen in 1054. In the next section, you will meet the neutron star found at the center of the Crab Nebula. The blue glow of the Crab Nebula is produced by synchrotron radiation. This form of electromagnetic radiation, unlike blackbody radiation, is produced by rapidly moving electrons spiraling through magnetic fields and is common in the nebulae produced by supernovae. In the case of the Crab Nebula, the electrons travel so fast that they emit visual wavelengths. In most such nebulae, the electrons move slower, and the synchrotron radiation is at radio wavelengths.

Atlantic Forest

It was the first environment that the Portuguese colonists encountered over 500 years ago, when it was thought to have had an area of 390,000-580,000 sq mi, and stretching an unknown distance inland. Over 85% of the original area has been deforested, threatening many plant and animal species with extinction. The Atlantic Forest is in Brazil on the Eastern side.

Accretion disk to novae

Mass transferred from one star to another in a binary system must conserve its angular momentum. Thus it must flow into a rapidly rotating whirlpool called an accretion disk around the second star, as shown in Figure 11-6. The gas in the disk grows hot because of friction and tidal forces (look back to Chapter 3 Section 3-5c) and eventually falls onto the second star. If that second star, the one receiving the matter lost from its companion, is a compact object like a white dwarf, the gas in the accretion disk can become very compressed. The gas temperature can exceed a million Kelvin, producing X-rays. In addition, the matter accumulating on the white dwarf can eventually cause a violent explosion called a nova. Nova explosions occur when mass transfers from a normal star into an accretion disk around a white dwarf. As the matter loses its angular momentum in the accretion disk, it settles inward onto the surface of the white dwarf and forms a layer of unused nuclear fuel—mostly hydrogen. As the layer deepens, it becomes denser and hotter until the hydrogen fuses in a sudden explosion that blows the surface off the white dwarf. Although the expanding cloud of debris contains less than 0.0001 solar mass, it is hot, and its expanding surface area makes it very luminous. Nova explosions can become 100,000 times more luminous than the Sun. As the debris cloud expands, cools, and thins over a period of weeks and months, the nova fades from view. The explosion of its surface hardly disturbs the white dwarf and its companion star. Mass transfer quickly resumes, and a new layer of fuel begins to accumulate. How fast the fuel builds up depends on the rate of mass transfer. Accordingly, you can expect novae to repeat each time an explosive layer accumulates. Many novae take thousands of years to build an explosive layer, but some take only decades.

what is meat made of?

Meat is mostly the muscle tissue of an animal. Most animal muscle is roughly 75% water, 20% protein, and 5% fat, carbohydrates, and assorted proteins. Muscles are made of bundles of cells called fibers. Each cell is crammed with filaments made of two proteins: actin and myosin. In a live animal, these protein filaments make muscles contract and relax. Both actions require enormous amounts of energy, which they get from the energy-carrying molecule ATP (adenosine triphosphate). The most efficient generation of ATP requires oxygen, which muscles get from circulating blood. After an animal is slaughtered, blood circulation stops, and muscles exhaust their oxygen supply. Muscle can no longer use oxygen to generate ATP and turn to anaerobic glycolysis, a process that breaks down sugar without oxygen, to generate ATP from glycogen, a sugar stored in muscle. The breakdown of glycogen produces enough energy to contract the muscles, and also produces lactic acid. With no blood flow to carry the lactic acid away, the acid builds up in the muscle tissue. If the acid content is too high, the meat loses its water-binding ability and becomes pale and watery. If the acid is too low, the meat will be tough and dry. Lactic acid buildup also releases calcium, which causes muscle contraction. As glycogen supplies are depleted, ATP regeneration stops, and the actin and myosin remain locked in a permanent contraction called rigor mortis. Freezing the carcass too soon after death keeps the proteins all bunched together, resulting in very tough meat. Aging allows enzymes in the muscle cells to break down the overlapping proteins, which makes the meat tender. Individual protein molecules in raw meat are wound-up in coils, which are formed and held together by bonds. When meat is heated, the bonds break and the protein molecule unwinds. Heat also shrinks the muscle fibers both in diameter and in length as water is squeezed out and the protein molecules recombine, or coagulate. Because the natural structure of the protein changes, this process of breaking, unwinding, and coagulating is called denaturing.

How do dimmer switches for lights work?

Most residential dimmer switches are built around a thyristor, with a variable resistor and capacitor to adjust the duty cycle of AC power. A thyristor acts like a voltage controlled switch, and the variable resistor limits how quickly the voltage of the capacitor rises or falls. While the voltage of the capacitor is above a certain level, the thyristor's gate will have a high enough potential to allow current to flow through the light bulb. When the voltage across the capacitor falls below that value, no energy will be delivered to the bulb. The longer it takes for the capacitor to charge, the less of each AC cycle will be allowed through by the thyristor, which decreases the power delivered to the bulb (controlling brightness).

satellite cells

Myosatellite cells, also known as satellite cells or muscle stem cells, are small multipotent cells with very little cytoplasm found in mature muscle. Satellite cells are precursors to skeletal muscle cells, able to give rise to satellite cells or differentiated skeletal muscle cells.

LIGO Mirrors

Normally, glass isn't reflective. Metal reflects because light waves shake its freely moving electrons, which absorb and reemit photons in the process. Glass, by contrast, lets most light pass through because its electrons stay within their atoms and don't interact much with light. But LIGO makes mirrors out of glass using a trick first invented in 1939. The mirrors consist of 70 layers of glass that alternate between silicon oxide glass (or "silica," the material of most glass) and tantalum pentoxide ("tantala"). Each layer reflects a small fraction of the light. The thickness of each layer is chosen with exquisite precision so that, for the exact wavelength of LIGO's laser, all the reflections constructively interfere, adding up to a mirror that's 99.9999% reflective. LIGO's mirrors are imperfect, however, because of a strange form of noise that is baked into glass, a mysterious substance in general. Glass consists of atoms or molecules that are haphazardly arranged like those in a liquid yet somehow stuck, unable to flow. Physicists believe that the noise inherent in glass comes from small clusters of atoms switching back and forth between two different configurations. These "two-level systems" ever so slightly change the distance laser light travels between LIGO's mirrors, since the surface of each glassy layer shifts by as much as an atom's width. There's hope, though. Fueled by recent theoretical insights about the nature of glass, Hellman's group and others are racing to find more perfect glass to use in LIGO's mirrors. Advanced LIGO Plus, the next iteration of the experiment, slated to begin in 2024, will require mirrors that are less than half as noisy as the current ones. In conjunction with other upgrades, this improvement will translate into seven times more gravitational-wave detections — approximately one every few hours.

Coronal heating problem

One possible mechanism for coronal heating is called 'wave heating'. Prof Alan Hood from the Solar and Magnetospheric Theory Group at St. Andrews explains: "The Sun has a very strong magnetic field which can carry waves upwards from the bubbling solar surface. Then these waves dump their energy in the corona, like ordinary ocean waves crashing on a beach. The energy of the wave has to go somewhere and in the corona it heats the electrified gases to incredible temperatures." The other rival mechanism is dependent on twisting the Sun's magnetic field beyond breaking point. Prof Richard Harrison of the UK's Rutherford Appleton Laboratory says "The Sun's magnetic field has loops, known to be involved in the processes of sun spots and solar flares. These loops reach out into the Sun's corona and can become twisted. Like a rubber band, they can become so twisted that eventually they snap. When that happens, they release their energy explosively, heating the coronal gases very rapidly".

Hulse-Taylor binary

PSR B1913+16 is a pulsar which, together with another neutron star, orbit around a common center of mass, thus forming a binary star system. PSR 1913+16 was the first binary pulsar to be discovered. PSR B1913+16 consists of two neutron stars separated by a distance roughly equal to the radius of our Sun. The masses of the two neutron stars are each about 1.4 solar masses, in good agreement with models of neutron stars and how they are created. A nice surprise was hidden in the motion of PSR B1913+16. In 1916, Albert Einstein published his general theory of relativity that described gravity as a curvature of space-time. Einstein realized that any rapid change in a gravitational field should spread outward at the speed of light as gravitational radiation. Taylor and Hulse were able to show that the orbital period of the binary pulsar is slowly growing shorter because the stars are radiating orbital energy away at exactly the rate expected for gravitational radiation and so are gradually spiraling toward each other. (Normal binary stars are too far apart and orbit too slowly to emit significant gravitational radiation.)

Photopolymerization

Photopolymerization is a technique that uses light (visible or ultraviolet; UV) to initiate and propagate a polymerization reaction to form a linear or crosslinked polymer structure. A photopolymer or light-activated resin is a polymer that changes its properties when exposed to light, often in the ultraviolet or visible region of the electromagnetic spectrum.[1] These changes are often manifested structurally, for example hardening of the material occurs as a result of cross-linking when exposed to light. An example is shown below depicting a mixture of monomers, oligomers, and photoinitiators that conform into a hardened polymeric material through a process called curing.[2][3] A wide variety of technologically useful applications rely on photopolymers, for example some enamels and varnishes depend on photopolymer formulation for proper hardening upon exposure to light. In some instances, an enamel can cure in a fraction of a second when exposed to light, as opposed to thermally cured enamels which can require half an hour or longer.[4] Curable materials are widely used for medical, printing, and photoresist technologies.

Quantum money from knots

Quantum money is a cryptographic protocol in which a mint can produce a quantum state, no one else can copy the state, and anyone (with a quantum computer) can verify that the state came from the mint. We present a concrete quantum money scheme based on superpositions of diagrams that encode oriented links with the same Alexander polynomial. We expect our scheme to be secure against computationally bounded adversaries.

Quorn

Quorn is a meat substitute product originating in the UK and sold primarily in Europe, but is available in 18 countries.[1] Quorn is sold as both a cooking ingredient and as the meat substitute used in a range of prepackaged meals. All Quorn foods contain mycoprotein as an ingredient, which is derived from the Fusarium venenatum fungus.[2] In most Quorn products, the fungus culture is dried and mixed with egg albumen, which acts as a binder, and then is adjusted in texture and pressed into various forms. A vegan formulation also exists that uses potato protein as a binder instead of egg albumen. Quorn is made from the soil mould Fusarium venenatum strain PTA-2684 (previously misidentified as the parasitic mould Fusarium graminearum[35]). The fungus is grown in continually oxygenated water in large, otherwise sterile fermentation tanks. Glucose and fixed nitrogen are added as a food for the fungus, as are vitamins and minerals to improve the food value of the product. The resulting mycoprotein is then extracted and heat-treated to remove excess levels of RNA. Previous attempts to produce such fermented protein foodstuffs were thwarted by excessive levels of DNA or RNA; without the heat treatment, purines, found in nucleic acids, are metabolised by humans to produce uric acid, which can lead to gout.[36] However two recent studies have found dietary factors once believed to be associated with gout are in fact not, including the intake of purine-rich vegetables and total protein.[37][38] The Mayo Clinic, meanwhile, advises gout sufferers to avoid some foods that are high in purines.[39]

SN 1987A

SN 1987A was a type II supernova in the Large Magellanic Cloud, a dwarf galaxy satellite of the Milky Way. It occurred approximately 51.4 kiloparsecs from Earth and was the closest observed supernova since Kepler's Supernova in 1604. One observation of SN 1987A is critical in that it confirms the hypothesis of core collapse. About 3 hours before the supernova was first noticeable in photographs, a blast of neutrinos swept through Earth. Instruments buried in a salt mine under Lake Erie and in a lead mine in Japan, though designed for another purpose, recorded 19 neutrinos in less than 15 seconds. Neutrinos are so difficult to detect that the 19 neutrinos actually detected mean that some 10^17 neutrinos must have passed through the detectors in those 15 seconds. Furthermore, the neutrinos were arriving from the direction of the supernova. Thus, astronomers conclude that the burst of neutrinos was released when the iron core collapsed, and the supernova was first seen at visual wavelengths hours later when the shock wave blasted the star's surface into space. The star that exploded as Supernova 1987A had about 20 times the mass of the Sun. Interactions of the burst of light and gas expanding from the explosion with material lost by the star during previous stages as a blue giant and red supergiant have produced rings around the central glow, as shown in the high-resolution image and the artist's conception. A shock wave from the explosion is now expanding into a 1 light-year-diameter ring of gas ejected roughly 20,000 years before the explosion. As that ring is excited, it is lighting up the region around it, revealing how the star shed mass before it collapsed.

brightest star in the sky

Sirius A The brightest star in the sky is Sirius, also known as the "Dog Star" or, more officially, Alpha Canis Majoris, for its position in the constellation Canis Major. Sirius is a binary star dominated by a luminous main sequence star, Sirius A, with an apparent magnitude of -1.46. Sirius Black from HP has a whole new meaning.

Nuclear Fusion in Massive Stars

Stars on the upper main sequence have too much mass to die as white dwarfs, but their evolution begins much like that of their lower-mass cousins. They consume the hydrogen in their cores, ignite hydrogen shells, and become giants or, for the most massive stars, supergiants. Their cores contract and fuse helium first in the core and then in a shell, producing a carbon-oxygen core. Unlike medium-mass stars, the massive stars finally can get hot enough to ignite carbon fusion at a temperature of about 1 billion Kelvin. Carbon fusion produces more oxygen plus neon. As soon as the carbon is exhausted in the core, the core contracts, and carbon ignites in a shell. This pattern of core ignition and shell ignition continues with a series of heavier nuclei as fusion fuel, and the star develops a layered structure as shown in Figure 11-7, with a hydrogen-fusion shell surrounding a helium-fusion shell surrounding a carbon-fusion shell surrounding ... and so on. At higher temperatures than carbon fusion, nuclei of oxygen, neon, and magnesium fuse to make silicon and sulfur, and at even higher temperatures silicon can fuse to make iron. The fusion of the nuclear fuels in this series goes faster and faster as the massive star evolves rapidly. The amount of energy released per fusion reaction decreases as the mass of the types of atoms involved increases. To support its weight and remain stable, a star must fuse oxygen much faster than it fused hydrogen. Also, there are fewer nuclei in the core of the star by the time heavy nuclei begin to fuse. Four hydrogen nuclei make one helium nucleus, and three helium nuclei make one fusion can last 7 million years in a 25-solar-mass star, but that same star will fuse its oxygen in 6 months and its silicon in just 1 day. The image is a magnified image of the core by 100,000 times magnification. Silicon fusion produces iron, the most tightly bound of all atomic nuclei (see Figure 10-5). Nuclear fusion releases energy only when less tightly bound nuclei combine into a more tightly bound nucleus. Once the gas in the core of the star has been converted to iron, there are no further nuclear reactions that can release energy. The iron core is a dead end in the evolution of a massive star. As a star develops an iron core, energy production begins to decline, and the core contracts. Nuclear reactions involving iron begin, but they remove energy from the core, causing it to contract even further. Once this process starts, the core of the star collapses inward in less than a tenth of a second. The collapse of a giant star's core after iron fusion starts is calculated to happen so rapidly that the most powerful computers are unable to predict the details. Thus, models of supernova explosions contain many approximations. Nevertheless, the models predict exotic nuclear reactions in the collapsing core that should produce a flood of neutrinos (look back to Chapter 10 Section 10-2c). In fact, for a short time the core produces more energy per second than all of the stars in all of the visible galaxies in the Universe, and 99 percent of that energy is in the form of neutrinos. This flood of neutrinos carries large amounts of energy out of the core, allowing the core to collapse further. The models also predict that the collapsing core of the star must quickly become a neutron star or a black hole, the subjects of the next sections of this chapter, while the envelope of the star is blasted outward. To understand how the inward collapse of the core can produce an outward explosion, you can think about a traffic jam. The collapse of the innermost part of the degenerate core allows the rest of the core to fall inward, and this creates a tremendous traffic jam as all of the nuclei fall toward the center. The position of the traffic jam, called a shock wave, begins to move outward as more in-falling material encounters the jam. The torrent of neutrinos, as well as energy flowing out of the core in sudden violent convective turbulence, help drive the shock wave outward. Within a few hours, the shock wave bursts outward through the surface of the star and blasts it apart. The supernova seen from Earth is the brightening of the star as its envelope is blasted outward by the shock wave. As months pass, the cloud of gas expands, thins, and fades, but the manner in which it fades tells astronomers more about the death throes of the star. The rate at which the supernova's brightness decreases matches the rate at which radioactive nickel and cobalt decay, so the explosion must produce great abundances of those atoms. The radioactive cobalt decays into iron, so destruction of iron in the core of the star is followed by the production of iron through nuclear reactions in the expanding outer layers.

closest satellite galaxy to milky way

The Large Magellanic Cloud (LMC) is a satellite dwarf galaxy of the Milky Way that is among the closest galaxies to Earth. At about 163,000 light-years from Earth, the dwarf galaxy looks like a faint cloud in Southern Hemisphere skies 30 billion stars Andromeda is 2.537 million light years away. Idk why people say this is the closest "galaxy".

fish maw

The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish to control their buoyancy, and thus to stay at their current water depth without having to waste energy in swimming. Fish maw contains rich proteins and nutrients such as phosphor and calcium. It nourishes 'yin', replenishes kidney and boosts stamina. ... Furthermore, fish maw does not contain cholesterol and therefore it is a very valuable health enhancing ingredient suitable for long time consumption.

bio-artificial muscles

The human bio-artificial muscle (BAM) is formed in a seven day tissue engineering procedure during which human myoblasts fuse and differentiate to aligned myofibers in an extracellular matrix. The dimensions of the BAM constructs allow for injection and follow-up during several days after injection. Electric field actuation Electroactive polymers (EAPs) are polymers that can be actuated through the application of electric fields. Currently, the most prominent EAPs include piezoelectric polymers, dielectric actuators (DEAs), electrostrictive graft elastomers, liquid crystal elastomers (LCE) and ferroelectric polymers. While these EAPs can be made to bend, their low capacities for torque motion currently limit their usefulness as artificial muscles. Moreover, without an accepted standard material for creating EAP devices, commercialization has remained impractical. However, significant progress has been made in EAP technology since the 1990s.[7] Ion-based actuation Ionic EAPs are polymers that can be actuated through the diffusion of ions in an electrolyte solution (in addition to the application of electric fields). Current examples of ionic electroactive polymers include polyelectrode gels, ionomeric polymer metallic composites (IPMC), conductive polymers and electrorheological fluids (ERF). In 2011, it was demonstrated that twisted carbon nanotubes could also be actuated by applying an electric field. Pneumatic actuation Thermal actuation Shape-memory alloys

turnoff point

The point on an H-R diagram where the stars in a cluster are leaving the main sequence. As a star cluster ages, its main sequence grows shorter, like a candle burning down. You can judge the age of a star cluster by looking at the turnoff point, the point on the main sequence where stars are currently evolving to the right to become giants. Stars at the turnoff point have lived out their lives and are about to die. Consequently, the life expectancy of the stars at the turnoff point equals the age of the cluster.

Gel electrophoresis

The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel. Procedure used to separate and analyze DNA fragments by placing a mixture of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel. The smallest fragments will move the furthest over and the largest ones will move the least.

3D stem cell printing technology

The stem cells are printed in a hydrogel solution using a special 3D printer they call ITOP. This printer makes it possible for the printed stem cells to develop into life-sized tissues and organs that have built-in microchannels that allow blood, oxygen and other nutrients to flow through.

Roche lobe

The volume of space a star controls gravitationally within a binary system. A teardrop-shaped volume surrounding a star in a binary inside which gases are gravitationally bound to that star. Binary stars can sometimes interact by transferring mass from one star to the other. Of course, the gravitational field of each star holds its mass together, but the gravitational fields of the two stars, combined with the rotation of the binary system, define a dumbbell-shaped volume called the Roche lobes around the pair of stars. Matter inside a star's Roche lobe is gravitationally bound to the star, but matter outside the lobe can be transferred to the other star or lost completely from the system. Matter flowing from one star to another cannot fall directly into the star. Rather, because of conservation of angular momentum, it must flow into a whirling disk around the star

Type ! vs Type II Supernovae

Type I supernovae have no hydrogen lines in their spectra whereas Type II supernovae spectra have hydrogen lines. Type II supernovae appear to be produced by the collapse and explosion of a massive star, the process discussed in the previous section. A Type Ia supernova evidently occurs when a white dwarf in a binary system receives enough mass to exceed the Chandrasekhar limit and collapse. The collapse of a white dwarf is different from the collapse of a massive star because the core of the white dwarf contains usable fuel. As the collapse begins, the temperature and density shoot up, and the carbon-oxygen core begins to fuse in violent nuclear reactions. In a few seconds, the carbon-oxygen core interior is entirely consumed, and the outermost layers are blasted away in a violent explosion that, at its brightest, is about six times more luminous than a Type II supernova. The white dwarf is destroyed; no neutron star or black hole is left behind. This explains why no hydrogen lines are seen in the spectrum of a Type Ia supernova explosion—white dwarfs contain very little hydrogen. The less common Type Ib supernova is understood to occur when a massive star in a binary system loses its hydrogen-rich outer layers to its companion star. The remains of the massive star could develop an iron core and collapse, as described in the previous section, producing a supernova explosion that lacked hydrogen lines in its spectrum.

Why are planes white? Why are some black?

White to reflect heat. Why black? Military aircraft flying at night have often been painted black or other dark colors, applied to just the underside of some aircraft and to the entirety of others, in the hope of reducing the risk of being seen in enemy searchlights or by night fighters.

Red dwarfs

What astronomers know about stellar evolution indicates that these red dwarfs should use up nearly all of their hydrogen and live very long lives on the lower main sequence. They could survive for a hundred billion years or more. Of course, astronomers can't test this part of their theories because the Universe is only 13.8 billion years old (see Chapter 14), so not a single red dwarf has died of old age anywhere in the Universe. Every red dwarf that has ever been born is still glowing today.

What makes pulsars pulse?

Why a neutron star emits beams of electromagnetic radiation is one of the challenging problems of modern astronomy, but astronomers have a general idea. A neutron star contains a powerful magnetic field and spins very rapidly. The spinning magnetic field generates a tremendously powerful electric field, and the field causes the production of electron-positron (matter-antimatter) pairs. As these charged particles are accelerated through the magnetic field, they emit photons in the direction of their motion, which produce powerful beams of radiation emerging from the magnetic poles of the neutron star. lighthouse model: The explanation of a pulsar as a spinning neutron star sweeping beams of electromagnetic radiation around the sky. The name pulsar is, in a sense, inaccurate: A pulsar does not pulse (vibrate) but rather emits beams of radiation that sweep around the sky as the neutron star rotates, like a rotating lighthouse light. The mechanism that produces the beams involves extremely high energies and strong electric and magnetic fields and is not fully understood. More than 1000 pulsars are now known. There might be many more which are undetected because their beams never point toward Earth. When a pulsar first forms, it might be spinning as many as 100 times a second. The energy it radiates into space ultimately comes from its energy of rotation, so as it blasts beams of radiation outward, its rotation slows. Judging from their pulse periods and rates at which they slow down, the average pulsar is apparently only a few million years old and the oldest has an age of about 10 million years. Presumably, neutron stars older than that rotate too slowly to generate detectable radio beams. Supernova remnants last only about 50,000 years before they mix into the interstellar medium and disappear, so most pulsars have long outlived the remnants in which they were originally embedded. The explosion of Supernova 1987A in February 1987 probably formed a neutron star. You can draw this conclusion because a burst of neutrinos was detected passing through Earth, and theory predicts that the collapse of a massive star's core into a ball of neutrons would produce such a burst of neutrinos. The neutron star initially should be hidden at the center of the expanding shells of gas ejected into space by the supernova explosion, but as the gas continues to expand and become thinner, you can expect that astronomers might eventually be able to detect it. As of this writing (October 2016), no neutron star has been detected in the SN 1987A remnant, but astronomers continue to watch the site hoping to find the youngest pulsar known.

camera obscura

a darkened enclosure in which images of outside objects are projected through a small aperture or lens onto a facing surface Rays of light travel in straight lines and change when they are reflected and partly absorbed by an object, retaining information about the color and brightness of the surface of that object. Lit objects reflect rays of light in all directions. A small enough opening in a screen only lets through rays that travel directly from different points in the scene on the other side, and these rays form an image of that scene when they are collected on a surface opposite from the opening. The human eye (as well as those of other animals including birds, fish, reptiles etc.) works much like a camera obscura with an opening (pupil), a biconvex lens and a surface where the image is formed (retina).

Agar

a gel-like polysaccharide compound used for culturing microbes; extracted from certain red algae Agar is a mixture of two components: the linear polysaccharide agarose, and a heterogeneous mixture of smaller molecules called agaropectin.[2] It forms the supporting structure in the cell walls of certain species of algae, and is released on boiling. These algae are known as agarophytes, and belong to the Rhodophyta (red algae) phylum.

Green Fluorescent Protein (GFP)

a protein that fluoresces green and is widely used in genetic analysis a protein that exhibits bright green fluorescence when exposed to blue light Green fluorescent protein (GFP) is a protein in the jellyfish Aequorea Victoria that exhibits green fluorescence when exposed to light. The protein has 238 amino acids, three of them (Numbers 65 to 67) form a structure that emits visible green fluorescent light.

White dwarf

a small very dense star that is typically the size of a planet. A white dwarf is formed when a low-mass star has exhausted all its central nuclear fuel and lost its outer layers as a planetary nebula. A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth. In fact, it is about the size of Earth. Dividing its mass by its volume reveals that it is very dense—about 2 x 10^6 g/cm^3 . On Earth, a teaspoonful of Sirius B material would weigh more than 10 tons. These basic observations and simple physics lead to the conclusion that white dwarfs are astonishingly dense. A white dwarf's future is bleak. As it radiates energy into space, its temperature gradually falls, but it cannot shrink any smaller because its degenerate electrons cannot get closer together. This degenerate matter is a very good thermal conductor, so heat flows to the surface and escapes into space, and the white dwarf gets fainter and cooler, moving downward and to the right in the H-R diagram. Because the white dwarf contains a tremendous amount of heat, it needs billions of years to radiate that heat through its small surface area. The coolest white dwarfs in our Galaxy are about the same temperature as of the Sun.

Heterocyst

a specialized cell that engages in nitrogen fixation in some filamentous cyanobacteria Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc punctiforme, Cylindrospermum stagnale, and Anabaena sphaerica.[1] They fix nitrogen from dinitrogen (N2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis.[2] Nitrogenase is inactivated by oxygen, so the heterocyst must create a microanaerobic environment. The heterocysts' unique structure and physiology require a global change in gene expression. For example, heterocysts: produce three additional cell walls, including one of glycolipid that forms a hydrophobic barrier to oxygen produce nitrogenase and other proteins involved in nitrogen fixation degrade photosystem II, which produces oxygen up-regulate glycolytic enzymes produce proteins that scavenge any remaining oxygen contain polar plugs composed of cyanophycin which slows down cell-to-cell diffusion Cyanobacteria usually obtain a fixed carbon (carbohydrate) by photosynthesis. The lack of water-splitting in photosystem II prevents heterocysts from performing photosynthesis, so the vegetative cells provide them with carbohydrates, which is thought to be sucrose. The fixed carbon and nitrogen sources are exchanged through channels between the cells in the filament. Heterocysts maintain photosystem I, allowing them to generate ATP by cyclic photophosphorylation.

open cluster

a star cluster that has a loose, disorganized appearance and contains no more than a few thousand stars An open cluster is a collection of 10 to 1000 stars in a region about 25 pc in diameter. Some open clusters are quite small, and some are large, but they all have an open, transparent appearance because the stars are not crowded together.

preposition

a word governing, and usually preceding, a noun or pronoun and expressing a relation to another word or element in the clause, as in "the man on the platform," "she arrived after dinner," "what did you do it for ?".

Binary Pulsars

because of the strength of gravity at the surface of a neutron star. Matter falling onto a neutron star can release titanic amounts of energy. If you dropped an ordinary apple onto the surface of a neutron star from a distance of 1 AU, it would hit with an impact equivalent to a 1-megaton nuclear warhead. Even a small amount of matter flowing from a companion star to a neutron star can generate high temperatures and release X-rays and gamma-rays. Image: Sometimes the X-ray pulses from Hercules X-1 are on, and sometimes they are off. A graph of X-ray intensity versus time looks like the light curve of an eclipsing binary. (b) In Hercules X-1, matter flows from a star into an accretion disk around a neutron star producing X-rays, which heat the near side of the star to 20,000 K compared with only 7000 K on the far side. X-rays turn off from Earth's point of view when the neutron star is eclipsed behind the star.

Laminar flow hood

contained, controlled area designed to produce laminar columns of sterile, pyrogen-free air as a sterile environment for aseptic production of parenteral products. A laminar flow cabinet or tissue culture hood is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive materials. Air is drawn through a HEPA filter and blown in a very smooth, laminar flow towards the user. Due to the direction of air flow, the sample is protected from the user but the user is not protected from the sample. The cabinet is usually made of stainless steel with no gaps or joints where spores might collect.[1]

bicephalism

having two heads.

Seagulls "stamp" thier feet on grass/dirt to mimic the rain and lure worms to them.

https://www.youtube.com/watch?v=-dU8PYR5i-w&feature=youtu.be

Grafting

method of propagation used to reproduce seedless plants and varieties of woody plants that cannot be propagated from cuttings Grafting or graftage[1] is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion (/ˈsaɪən/) while the lower part is called the rootstock. The success of this joining requires that the vascular tissues grow together and such joining is called inosculation. Advantages Precocity: The ability to induce fruitfulness without the need for completing the juvenile phase. Juvenility is the natural state through which a seedling plant must pass before it can become reproductive. In most fruiting trees, juvenility may last between 5 and 9 years, but in some tropical fruits, e.g., mangosteen, juvenility may be prolonged for up to 15 years. Grafting of mature scions onto rootstocks can result in fruiting in as little as two years. Dwarfing: To induce dwarfing or cold tolerance or other characteristics to the scion. Most apple trees in modern orchards are grafted on to dwarf or semi-dwarf trees planted at high density. They provide more fruit per unit of land, of higher quality, and reduce the danger of accidents by harvest crews working on ladders. Care must be taken when planting dwarf or semi-dwarf trees. If such a tree is planted with the graft below the soil, then the scion portion can also grow roots and the tree will still grow to its standard size. Disease/pest resistance: In areas where soil-borne pests or pathogens would prevent the successful planting of the desired cultivar, the use of pest/disease tolerant rootstocks allow the production from the cultivar that would be otherwise unsuccessful. A major example is the use of rootstocks in combating Phylloxera. Pollen source: To provide pollenizers. For example, in tightly planted or badly planned apple orchards of a single variety, limbs of crab apple may be grafted at regularly spaced intervals onto trees down rows, say every fourth tree. This takes care of pollen needs at blossom time.

Adipogenesis

production of fat, either fatty degeneration or fatty infiltration Adipocytes play a vital role in energy homeostasis and process the largest energy reserve as triglycerol in the body of animals.[3] Adipocytes stay in a dynamic state, they start expanding when the energy intake is higher than the expenditure and undergo mobilization when the energy expenditure exceeds the intake. This process is highly regulated by counter regulatory hormones to which these cells are very sensitive. The hormone insulin promotes expansion whereas the counter hormones epinephrine, glucagon, and ACTH promote mobilization. Adipogenesis is a tightly regulated cellular differentiation process, in which mesenchymal stem cells committing to preadipocytes and preadipocytes differentiating into adipocytes. Cellular differentiation is a change of gene expression patterns which multipotent gene expression alters to cell type specific gene expression. Therefore, transcription factors are crucial for adipogenesis. Transcription factors, peroxis proliferator-activated receptor γ (PPARγ) and CCAAT enhancer-binding proteins (C/EBPs) are main regulators of adipogenesis.[4] Comparing with cells from other lineage, the in vitro differentiation of fat cells is authentic and recapitulates most of the characteristic feature of in vivo differentiation. The key features of differentiated adipocytes are growth arrest, morphological change, high expression of lipogenic genes and production of adipokines like adiponectin, leptin, resistin (in the mouse, not in humans) and TNF-alpha. Adipose tissue-derived stem cells (ADSCs) are mesenchymal cells with the capacity for self-renewal and multipotential differentiation. This multipotentiality allows them to become adipocytes, chondrocytes, myocytes, osteoblasts and neurocytes among other cell lineages

Chandrasekhar limit

the most mass a white dwarf can have before annihilating in a thermonuclear blast (supernova) The maximum mass of a white dwarf, about 1.4 solar masses. A white dwarf of greater mass cannot support itself and will collapse. Can stars lose substantial amounts of mass? Observations provide clear evidence that young stars have strong stellar winds, and aging giants and supergiants also lose mass. This suggests that stars more massive than the Chandrasekhar limit can eventually end up as white dwarfs if they reduce their mass under the limit. Theoretical models show that stars that begin life with as much as 8 solar masses could lose mass fast enough to reduce their mass so low they could collapse to form white dwarfs with masses below 1.4 solar masses. With mass loss, a wide range of medium-mass stars could eventually die as white dwarfs.

Ion chromatography

the stationary phase is an ion-exchange resin, and the detection is ordinarily accomplished by a conductivity detector Ion chromatography (or ion-exchange chromatography) is a chromatography process that separates ions and polar molecules based on their affinity to the ion exchanger. It works on almost any kind of charged molecule—including large proteins, small nucleotides, and amino acids. However, ion chromatography must be done in conditions that are one unit away from the isoelectric point of a protein.