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In nature H. rhamnoides is found growing profusely on a wide range of soil types, but does better in soils with a light physical structure, rich in nutrient compounds and with a pH near neutral (pH 6.5–7.5). Best growth occurs in deep, well drained, sandy loam with ample organic matter. Very light, sandy soils have low water carrying capacity and are also low in nutrient mineral elements; so without the previous addition of organic matter, are not appropriate. Similarly inappropriate are clayey soils, with high density and water retention characteristics.H. | https://en.wikipedia.org/wiki/Common_sea-buckthorn |
rhamnoides is considered drought resistant but it is a moisture sensitive plant especially in the spring when plants are flowering and young fruits are beginning to develop. Planting in arid or semiarid areas is possible, if water is supplied for establishment. It can bear fruits at altitudes up to 2000 m above sea level. | https://en.wikipedia.org/wiki/Common_sea-buckthorn |
The plant can withstand temperatures from −43 °C to + 40 °C. Vegetation begins at average daily air temperatures of 5 to 7 °C. It flowers at temperatures 10 to 15 °C and requires total effective temperatures, spring to harvest time, of 14.5 °C to 17.5 °C, depending on latitude, elevation and species. | https://en.wikipedia.org/wiki/Common_sea-buckthorn |
Frost hardiness is the highest in deep dormancy in November and December. During this period, negative temperatures of −50 °C may be tolerated. | https://en.wikipedia.org/wiki/Common_sea-buckthorn |
Whereas in the post-dormant period in January to March, the critical temperature drops in air temperature for the male to −30 °C to −35 °C and for the female, −40 °C to −45 °C. H. rhamnoides can only be grown in well-lit, unshaded areas. Starting from its very earliest stage of development, it can not tolerate shade. As for fertilization, phosphorus is indispensable for the normal life process of the nodules on the roots. The plant requires little nitrogen, due to its ability to fix nitrogen. | https://en.wikipedia.org/wiki/Common_sea-buckthorn |
In nature and human societies, many phenomena have causal relationships where one phenomenon A (a cause) impacts another phenomenon B (an effect). Establishing causal relationships is the aim of many scientific studies across fields ranging from biology and physics to social sciences and economics. It is also a subject of accident analysis, and can be considered a prerequisite for effective policy making. To describe causal relationships between phenomena, non-quantitative visual notations are common, such as arrows, e.g. in the nitrogen cycle or many chemistry and mathematics textbooks. | https://en.wikipedia.org/wiki/Causal_notation |
Mathematical conventions are also used, such as plotting an independent variable on a horizontal axis and a dependent variable on a vertical axis, or the notation y = f ( x ) {\displaystyle y=f(x)} to denote that a quantity " y {\displaystyle y} " is a dependent variable which is a function of an independent variable " x {\displaystyle x} ". Causal relationships are also described using quantitative mathematical expressions.The following examples illustrate various types of causal relationships. These are followed by different notations used to represent causal relationships. | https://en.wikipedia.org/wiki/Causal_notation |
In nature bacteria play a major role in the degradation of phosphonates. Due to the presence of natural phosphonates in the environment, bacteria have evolved the ability to metabolize phosphonates as nutrient sources. Some bacteria use phosphonates as a phosphorus source for growth. Aminophosphonates can also be used as sole nitrogen source by some bacteria. | https://en.wikipedia.org/wiki/Phosphonate |
The polyphosphonates used in industry differ greatly from natural phosphonates such as 2-aminoethylphosphonic acid, because they are much larger, carry a high negative charge and are complexed with metals. Biodegradation tests with sludge from municipal sewage treatment plants with HEDP and NTMP showed no indication for any degradation. An investigation of HEDP, NTMP, EDTMP and DTPMP in standard biodegradation tests also failed to identify any biodegradation. | https://en.wikipedia.org/wiki/Phosphonate |
It was noted, however, that in some tests due to the high sludge to phosphonate ratio, removal of the test substance from solution observed as loss of DOC was observed. This factor was attributed to adsorption rather than biodegradation. However, bacterial strains capable of degrading aminopolyphosphonates and HEDP under P-limited conditions have been isolated from soils, lakes, wastewater, activated sludge and compost. | https://en.wikipedia.org/wiki/Phosphonate |
"No biodegradation of phosphonates during water treatment is observed but photodegradation of the Fe(III)-complexes is rapid. Aminopolyphosphonates are also rapidly oxidized in the presence of Mn(II) and oxygen and stable breakdown products are formed that have been detected in wastewater. The lack of information about phosphonates in the environment is linked to analytical problems of their determination at trace concentrations in natural waters. Phosphonates are present mainly as Ca and Mg-complexes in natural waters and therefore do not affect metal speciation or transport." Phosphonates interact strongly with some surfaces, which results in a significant removal in technical and natural systems. | https://en.wikipedia.org/wiki/Phosphonate |
In nature conservation, a shifted baseline is a baseline for conservation targets and desired population sizes, that is based on non-pristine conditions. In this sense, the term was coined by marine biologist Daniel Pauly when he observed, that some fisheries scientists used the population sizes of fish at the beginning of their own careers to assess a desired baseline, notwithstanding whether the fishing stocks they used as baselines had already been diminished by human exploitation. He noticed, that the estimations these scientists took for reference markedly differed from historical accounts. Consequently, he concluded, that over generations the perception of what is considered to be normal would change, and so may what is considered a depleted population. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
Pauly called this the shifting baseline syndrome.In line with this, it may be argued that the prevalance of closed-canopy forest as the prevailing conservation narrative in Europe similarly arises from multiple shifted baselines: While it is plausble that lions, leopards, hyenas, dholes, gazelles and moon bears among other victims of European Quaternary and Holocene extinctions would still be native to Europe, had they not been evicted by humans, none of these species are listed as such in the EU's Habitats Directive's annexes. This absence in conservation law, if applied also to globally extinct megafauna, would imply that elephants and rhinos should be considered native to Europe, too, and hence any landscape that is considered to be natural, yet results from a situation where these are lacking, would necessarily be the consequence of a shifted baseline. It is very likely, that the megafauna extinctions of the late Pleistocene and early Holocene had profound implications for European and worldwide ecosystems, especially given the paramount importance comparable animals have for modern ecosystems. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
Vera points out that words like wold and forest would have had different connotations than they do today. While today, a forest is a dense and reasonably large tract of trees, the Medieval Latin forestis, from which it derives, would have assigned open stands of trees, and was a wild and uncultivated land home also to aurochs and wild horses. According to historical sources, these forestis included hawthorn, blackthorn, wild cherry, wild apple and wild pear, as well as oaks, all of which are light-demanding species that cannot regenerate successfully in closed-canopy forest. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
From this Vera concluded that the assumption by scholars of the 19th and 20th century that grazing animals destroyed the original European closed-canopy wildwoods still present in the early medieval period is based on a misinterpretation of these terms and is closely related to the severe overstocking characteristic of their own time, which in turn would have been a consequence of population growth following the industrial revolution.He further argues that from this initial misinterpretation another misinterpretation arose: that forest regeneration would naturally take place inside the forest. Thus, scholars of the 19th and 20th century would have interpreted medieval grazing regulations to allow tree regeneration in coppiced mantle and fringe vegetation as meant to allow for regeneration in a forest. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
During their time, solid firewood would have been preferred over the medieval coppice bundles, e.g. faggots. However, the production of firewood would have required the felling of trees at an age at which they cannot produce suckers anymore, an ability trees commonly lose with progressing age. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
This would then have led to a different management system: the replacement by saplings planted or naturally regenerated via, for example, shelterwood cuttings. Initially these trees regenerated inside the forests would have been differentiated from wild growth outside the forests. In German, the former would have been referred to as natural regeneration (Naturverjüngung) while the latter had another name: Holzwildwuchse. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
Thus, natural regeneration would not have been synonymous with the natural regeneration of trees in a natural situation. Only in the 19th and 20th centuries would this distinction have been abandoned in German. However, in the absence of thorny nurse bushes, which would have disappeared due to the shadow under the trees, the planted trees would then have had to be manually protected. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
Therefore, the "natural regeneration" would still have depended on work like ploughing, removal of browsing pressure and the suppression of weeds and thus was and is not "natural" in the ordinary sense of the word. Instead, according to Vera, the original meaning of the word "natural" in this context was that a seed had fallen from a tree and then grown by itself, as opposed to being planted. This shifted baseline of where regeneration of trees was to be expected, shifting from thorny fringes of groves in wood-pastures to the interior of closed tree stands, would then have led to the notion of herbivores being considered detrimental for forest regeneration and would have necessitated fenced-out areas, tree shelters and population control via hunting. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
Also because of this shifted baseline, cattle and horses would now have been considered "alien" to the landscape akin to invasive species and consequently removed from the forests, as it happened in former wood-pastures like Białowieża and other modern forest reserves, because they were seen as harmful to the creation of a new old-growth forest. At the same time, the introduction of the potato would have made pannage, the fattening of pigs on acorns, obsolete, and grass species specifically bred for a high yield would have superseded the traditional pasturing, mostly of cattle, in wood-pastures. Together, these mechanisms would have created the spatial separation between livestock rearing and forestry, grassland and forest enshrined into modern law and practice. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
Finally, the biodiversity losses associated with the conversion of open grassland, mantle and fringe vegetation and open-grown trees into closed-canopy forests would then have been legitimised by the assumption that the forest was the only natural ecosystem, and hence species losses were casualties of a natural cause.However, a strong argument that may put Vera's etymological evidence into perspective altogether is that the composition of medieval woodlands may not be relevant to their naturalness. Since by the medieval period agricultural traditions had already been ubiquitous in most of Europe for millennia, it may be unrealistic to assume that what people of the time perceived and labelled as wilderness may indeed have been one. Instead, it is doubtful that pristine conditions had survived in the Central- and Western European lowlands, Vera's area of study, at any rate up to this point. | https://en.wikipedia.org/wiki/Megaherbivore_theory |
In nature or crop fields, water is often the most limiting factor for plant growth. If plants do not receive adequate rainfall or irrigation, the resulting dehydration stress can reduce growth more than all other environmental stresses combined. Drought can be defined as the absence of rainfall or irrigation for a period of time sufficient to deplete soil moisture and cause dehydration in plant tissues. Dehydration stress results when water loss from the plant exceeds the ability of the plant's roots to absorb water and when the plant's water content is reduced enough to interfere with normal plant processes. | https://en.wikipedia.org/wiki/Breeding_for_drought_stress_tolerance |
In nature the ion is destroyed by reacting with other hydrogen molecules: H+2 + H2 → H+3 + H. | https://en.wikipedia.org/wiki/Hydrogen_molecule_ion |
In nature worship, a nature deity is a deity in charge of forces of nature, such as a water deity, vegetation deity, sky deity, solar deity, fire deity, or any other naturally occurring phenomena such as mountains, trees, or volcanoes. Accepted in panentheism, pantheism, deism, polytheism, animism, totemism, shamanism, and paganism, the deity embodies natural forces and can have various characteristics, such as that of a mother goddess, "Mother Nature", or lord of the animals. | https://en.wikipedia.org/wiki/Nature_deity |
In nature, DNA can form three structures, A-, B-, and Z-DNA. A- and B-DNA are very similar, forming right-handed helices, whereas Z-DNA is a left-handed helix with a zig-zag phosphate backbone. Z-DNA is thought to play a specific role in chromatin structure and transcription because of the properties of the junction between B- and Z-DNA. At the junction of B- and Z-DNA, one pair of bases is flipped out from normal bonding. | https://en.wikipedia.org/wiki/Chromatin_structure |
These play a dual role of a site of recognition by many proteins and as a sink for torsional stress from RNA polymerase or nucleosome binding.DNA bases are stored as a code structure with four chemical bases such as “Adenine (A), Guanine (G), Cytosine (C), and Thymine (T)”. The order and sequences of these chemical structures of DNA are reflected as information available for the creation and control of human organisms. “A with T and C with G” pairing up to build the DNA base pair. | https://en.wikipedia.org/wiki/Chromatin_structure |
Sugar and phosphate molecules are also paired with these bases, making DNA nucleotides arrange 2 long spiral strands unitedly called “double helix”. In eukaryotes, DNA consists of a cell nucleus and the DNA is providing strength and direction to the mechanism of heredity. Moreover, between the nitrogenous bonds of the 2 DNA, homogenous bonds are forming. | https://en.wikipedia.org/wiki/Chromatin_structure |
In nature, DNA molecules are synthesised by all living cells through the process of DNA replication. This typically occurs as a part of cell division. DNA replication occurs so, during cell division, each daughter cell contains an accurate copy of the genetic material of the cell. In vivo DNA synthesis (DNA replication) is dependent on a complex set of enzymes which have evolved to act during the S phase of the cell cycle, in a concerted fashion. | https://en.wikipedia.org/wiki/DNA_synthesis |
In both eukaryotes and prokaryotes, DNA replication occurs when specific topoisomerases, helicases and gyrases (replication initiator proteins) uncoil the double-stranded DNA, exposing the nitrogenous bases. These enzymes, along with accessory proteins, form a macromolecular machine which ensures accurate duplication of DNA sequences. | https://en.wikipedia.org/wiki/DNA_synthesis |
Complementary base pairing takes place, forming a new double-stranded DNA molecule. This is known as semi-conservative replication since one strand of the new DNA molecule is from the 'parent' strand. Continuously, eukaryotic enzymes encounter DNA damage which can perturb DNA replication. | https://en.wikipedia.org/wiki/DNA_synthesis |
This damage is in the form of DNA lesions that arise spontaneously or due to DNA damaging agents. DNA replication machinery is therefore highly controlled in order to prevent collapse when encountering damage. Control of the DNA replication system ensures that the genome is replicated only once per cycle; over-replication induces DNA damage. | https://en.wikipedia.org/wiki/DNA_synthesis |
Deregulation of DNA replication is a key factor in genomic instability during cancer development.This highlights the specificity of DNA synthesis machinery in vivo. Various means exist to artificially stimulate the replication of naturally occurring DNA, or to create artificial gene sequences. However, DNA synthesis in vitro can be a very error-prone process. | https://en.wikipedia.org/wiki/DNA_synthesis |
In nature, Komagataella is found on trees, such as chestnut trees. They are heterotrophs and they can use several carbon sources for living, like glucose, glycerol and methanol. However, they cannot use lactose. | https://en.wikipedia.org/wiki/Pichia_pastoris |
In nature, S. sempervirens is primarily a plant of the seashore, and is accordingly found along coasts of the Atlantic Ocean, the Caribbean, and the Gulf of Mexico from Central America north as far as Newfoundland. It grows on sand dunes, salt marshes, and the banks of estuaries. It is naturally found inland along the St. Lawrence Seaway and the Great Lakes, and has expanded its range further inland along roadsides over the past 30 years. | https://en.wikipedia.org/wiki/Solidago_sempervirens |
It is highly tolerant of both saline soils and salt spray, and is usually found growing on coastal dunes and in salt marshes. VarietiesSolidago sempervirens var. mexicana (L.) Fernald - from Massachusetts south to Central America and the West Indies Solidago sempervirens var. sempervirens - from Newfoundland south to Virginia; introduced in Great Lakes region | https://en.wikipedia.org/wiki/Solidago_sempervirens |
In nature, a light source emits a ray of light which travels, eventually, to a surface that interrupts its progress. One can think of this "ray" as a stream of photons traveling along the same path. In a perfect vacuum this ray will be a straight line (ignoring relativistic effects). Any combination of four things might happen with this light ray: absorption, reflection, refraction and fluorescence. | https://en.wikipedia.org/wiki/Real-time_raytracing |
A surface may absorb part of the light ray, resulting in a loss of intensity of the reflected and/or refracted light. It might also reflect all or part of the light ray, in one or more directions. If the surface has any transparent or translucent properties, it refracts a portion of the light beam into itself in a different direction while absorbing some (or all) of the spectrum (and possibly altering the color). | https://en.wikipedia.org/wiki/Real-time_raytracing |
Less commonly, a surface may absorb some portion of the light and fluorescently re-emit the light at a longer wavelength color in a random direction, though this is rare enough that it can be discounted from most rendering applications. Between absorption, reflection, refraction and fluorescence, all of the incoming light must be accounted for, and no more. A surface cannot, for instance, reflect 66% of an incoming light ray, and refract 50%, since the two would add up to be 116%. From here, the reflected and/or refracted rays may strike other surfaces, where their absorptive, refractive, reflective and fluorescent properties again affect the progress of the incoming rays. Some of these rays travel in such a way that they hit our eye, causing us to see the scene and so contribute to the final rendered image. | https://en.wikipedia.org/wiki/Real-time_raytracing |
In nature, acarbose is synthesized by soil bacteria Actinoplanes sp through its precursor valienamine. And acarbose is also degraded by gut bacteria Lactobacillus plantarum and soil bacteria Thermus sp by acarbose degrading glucosidases. | https://en.wikipedia.org/wiki/Acarbose |
In nature, algal viruses have been observed to play an ecological role in algal bloom demise. Given this, scientists have proposed that algal viruses have the potential to be used as biological treatments for algal bloom control. For example, a particular algal virus, known as a cyanophage, can be used to control harmful algal blooms of cyanobacteria. Lytic cyanophages are often found in the presence of Microcystis cyanobacteria. | https://en.wikipedia.org/wiki/Algal_virus |
Specifically, the impact that cyanophages have on the population control of Microcystis aeruginosa has been a topic of interest given that this species of cyanobacteria is commonly responsible for harmful algal blooms. In one lab study, M. aeruginosa was collected and then treated with cyanophage that was found in the presence of M. aeruginosa in a lake. After six days, the M. aeruginosa algal biomass had decreased by 95 percent. | https://en.wikipedia.org/wiki/Algal_virus |
The results of another lab study showed that cyanophages maintain their observed function of algal bloom demise in a controlled eutrophic setting. In this case, the biomass of M. aeruginosa also greatly decreased when treated with cyanophages. | https://en.wikipedia.org/wiki/Algal_virus |
A negative correlation between M. aeruginosa and cyanophage has also been recorded in a natural setting. In the freshwater body, Lake Mikata, researchers analyzed samples of M. aeruginosa algal growth and found that the biomass of M. aeruginosa decreased in relation to an increase in cyanophage population density. == References == | https://en.wikipedia.org/wiki/Algal_virus |
In nature, approximations of parabolas and paraboloids are found in many diverse situations. The best-known instance of the parabola in the history of physics is the trajectory of a particle or body in motion under the influence of a uniform gravitational field without air resistance (for instance, a ball flying through the air, neglecting air friction). The parabolic trajectory of projectiles was discovered experimentally in the early 17th century by Galileo, who performed experiments with balls rolling on inclined planes. He also later proved this mathematically in his book Dialogue Concerning Two New Sciences. | https://en.wikipedia.org/wiki/Parabola |
For objects extended in space, such as a diver jumping from a diving board, the object itself follows a complex motion as it rotates, but the center of mass of the object nevertheless moves along a parabola. As in all cases in the physical world, the trajectory is always an approximation of a parabola. The presence of air resistance, for example, always distorts the shape, although at low speeds, the shape is a good approximation of a parabola. | https://en.wikipedia.org/wiki/Parabola |
At higher speeds, such as in ballistics, the shape is highly distorted and does not resemble a parabola. Another hypothetical situation in which parabolas might arise, according to the theories of physics described in the 17th and 18th centuries by Sir Isaac Newton, is in two-body orbits, for example, the path of a small planetoid or other object under the influence of the gravitation of the Sun. Parabolic orbits do not occur in nature; simple orbits most commonly resemble hyperbolas or ellipses. | https://en.wikipedia.org/wiki/Parabola |
The parabolic orbit is the degenerate intermediate case between those two types of ideal orbit. An object following a parabolic orbit would travel at the exact escape velocity of the object it orbits; objects in elliptical or hyperbolic orbits travel at less or greater than escape velocity, respectively. Long-period comets travel close to the Sun's escape velocity while they are moving through the inner Solar system, so their paths are nearly parabolic. | https://en.wikipedia.org/wiki/Parabola |
Approximations of parabolas are also found in the shape of the main cables on a simple suspension bridge. The curve of the chains of a suspension bridge is always an intermediate curve between a parabola and a catenary, but in practice the curve is generally nearer to a parabola due to the weight of the load (i.e. the road) being much larger than the cables themselves, and in calculations the second-degree polynomial formula of a parabola is used. Under the influence of a uniform load (such as a horizontal suspended deck), the otherwise catenary-shaped cable is deformed toward a parabola (see Catenary § Suspension bridge curve). | https://en.wikipedia.org/wiki/Parabola |
Unlike an inelastic chain, a freely hanging spring of zero unstressed length takes the shape of a parabola. Suspension-bridge cables are, ideally, purely in tension, without having to carry other forces, for example, bending. | https://en.wikipedia.org/wiki/Parabola |
Similarly, the structures of parabolic arches are purely in compression. Paraboloids arise in several physical situations as well. The best-known instance is the parabolic reflector, which is a mirror or similar reflective device that concentrates light or other forms of electromagnetic radiation to a common focal point, or conversely, collimates light from a point source at the focus into a parallel beam. | https://en.wikipedia.org/wiki/Parabola |
The principle of the parabolic reflector may have been discovered in the 3rd century BC by the geometer Archimedes, who, according to a dubious legend, constructed parabolic mirrors to defend Syracuse against the Roman fleet, by concentrating the sun's rays to set fire to the decks of the Roman ships. The principle was applied to telescopes in the 17th century. Today, paraboloid reflectors can be commonly observed throughout much of the world in microwave and satellite-dish receiving and transmitting antennas. | https://en.wikipedia.org/wiki/Parabola |
In parabolic microphones, a parabolic reflector is used to focus sound onto a microphone, giving it highly directional performance. Paraboloids are also observed in the surface of a liquid confined to a container and rotated around the central axis. In this case, the centrifugal force causes the liquid to climb the walls of the container, forming a parabolic surface. This is the principle behind the liquid-mirror telescope. Aircraft used to create a weightless state for purposes of experimentation, such as NASA's "Vomit Comet", follow a vertically parabolic trajectory for brief periods in order to trace the course of an object in free fall, which produces the same effect as zero gravity for most purposes. | https://en.wikipedia.org/wiki/Parabola |
In nature, camouflage is used by organisms to escape predators. This is achieved through creating an ambiguity of texture segmentation by imitating the surrounding environment. Without being able to perceive noticeable differences in texture and position, a predator will be unable to see their prey. | https://en.wikipedia.org/wiki/Reversible_figure |
In nature, carbon exists as three isotopes: two stable, nonradioactive (carbon-12 (12C), and carbon-13 (13C), and one radioactive carbon-14 (14C), also known as "radiocarbon"). The half-life of 14C (the time it takes for half of a given amount of 14C to decay) is about 5,730 years, so its concentration in the atmosphere might be expected to decrease over thousands of years, but 14C is constantly being produced in the lower stratosphere and upper troposphere, primarily by galactic cosmic rays, and to a lesser degree by solar cosmic rays. These cosmic rays generate neutrons as they travel through the atmosphere which can strike nitrogen-14 (14N) atoms and turn them into 14C. The following nuclear reaction is the main pathway by which 14C is created: n + 147N → 146C + p where n represents a neutron and p represents a proton.Once produced, the 14C quickly combines with the oxygen (O) in the atmosphere to form first carbon monoxide (CO), and ultimately carbon dioxide (CO2).14C + O2 → 14CO + O 14CO + OH → 14CO2 + H Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is taken up by plants via photosynthesis. | https://en.wikipedia.org/wiki/Radioactive_carbon_dating |
Animals eat the plants, and ultimately the radiocarbon is distributed throughout the biosphere. The ratio of 14C to 12C is approximately 1.25 parts of 14C to 1012 parts of 12C. In addition, about 1% of the carbon atoms are of the stable isotope 13C.The equation for the radioactive decay of 14C is:146C → 147N + e− + νe By emitting a beta particle (an electron, e−) and an electron antineutrino (νe), one of the neutrons in the 14C nucleus changes to a proton and the 14C nucleus reverts to the stable (non-radioactive) isotope 14N. | https://en.wikipedia.org/wiki/Radioactive_carbon_dating |
In nature, carbon fixation is done by green plants using the enzyme RuBisCO as a part of the Calvin cycle. RuBisCO is a rather slow catalyst compared to the vast majority of other enzymes, incorporating only a few molecules of carbon dioxide into ribulose-1,5-bisphosphate per minute, but does so at atmospheric pressure and in mild, biological conditions. The resulting product is further reduced and eventually used in the synthesis of glucose, which in turn is a precursor to more complex carbohydrates, such as cellulose and starch. | https://en.wikipedia.org/wiki/Artificial_Photosynthesis |
The process consumes energy in the form of ATP and NADPH. Artificial CO2 reduction for fuel production aims mostly at producing reduced carbon compounds from atmospheric CO2. Some transition metal polyphosphine complexes have been developed for this end; however, they usually require previous concentration of CO2 before use, and carriers (molecules that would fixate CO2) that are both stable in aerobic conditions and able to concentrate CO2 at atmospheric concentrations haven't been yet developed. The simplest product from CO2 reduction is carbon monoxide (CO), but for fuel development, further reduction is needed, and a key step also needing further development is the transfer of hydride anions to CO. | https://en.wikipedia.org/wiki/Artificial_Photosynthesis |
In nature, chloride is found primarily in seawater, which has a chloride ion concentration of 19400 mg/liter. Smaller quantities, though at higher concentrations, occur in certain inland seas and in subterranean brine wells, such as the Great Salt Lake in Utah and the Dead Sea in Israel. Most chloride salts are soluble in water, thus, chloride-containing minerals are usually only found in abundance in dry climates or deep underground. Some chloride-containing minerals include halite (sodium chloride NaCl), sylvite (potassium chloride KCl), bischofite (MgCl2∙6H2O), carnallite (KCl∙MgCl2∙6H2O), and kainite (KCl∙MgSO4∙3H2O). It is also found in evaporite minerals such as chlorapatite and sodalite. | https://en.wikipedia.org/wiki/Chloride_salt |
In nature, circular DNA is always isolated as a higher-order helix-upon-a-helix, known as a superhelix. In discussions of this subject, the Watson–Crick twist is referred to as a "secondary" winding, and the superhelices as a "tertiary" winding. The sketch at right indicates a "relaxed", or "open circular" Watson–Crick double-helix, and, next to it, a right-handed superhelix. The "relaxed" structure on the left is not found unless the chromosome is nicked; the superhelix is the form usually found in nature. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
For purposes of mathematical computations, a right-handed superhelix is defined as having a "negative" number of superhelical turns, and a left-handed superhelix is defined as having a "positive" number of superhelical turns. In the drawing (shown at the right), both the secondary (i.e., "Watson–Crick") winding and the tertiary (i.e., "superhelical") winding are right-handed, hence the supertwists are negative (–3 in this example). | https://en.wikipedia.org/wiki/Supercoiled_DNA |
The superhelicity is presumed to be a result of underwinding, meaning that there is a deficiency in the number of secondary Watson–Crick twists. Such a chromosome will be strained, just as a macroscopic metal spring is strained when it is either overwound or unwound. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
In DNA which is thusly strained, supertwists will appear. DNA supercoiling can be described numerically by changes in the linking number Lk. The linking number is the most descriptive property of supercoiled DNA. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
Lko, the number of turns in the relaxed (B type) DNA plasmid/molecule, is determined by dividing the total base pairs of the molecule by the relaxed bp/turn which, depending on reference is 10.4; 10.5; 10.6. L k o = b p / 10.4 {\displaystyle Lk_{o}=bp/10.4} Lk is the number of crosses a single strand makes across the other, often visualized as the number of Watson–Crick twists found in a circular chromosome in a (usually imaginary) planar projection. This number is physically "locked in" at the moment of covalent closure of the chromosome, and cannot be altered without strand breakage. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
The topology of the DNA is described by the equation below in which the linking number is equivalent to the sum of Tw, which is the number of twists or turns of the double helix, and Wr, which is the number of coils or "writhes." If there is a closed DNA molecule, the sum of Tw and Wr, or the linking number, does not change. However, there may be complementary changes in Tw and Wr without changing their sum: L k = T w + W r {\displaystyle Lk=Tw+Wr} Tw, called "twist," is the number of Watson–Crick twists in the chromosome when it is not constrained to lie in a plane. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
We have already seen that native DNA is usually found to be superhelical. If one goes around the superhelically twisted chromosome, counting secondary Watson–Crick twists, that number will be different from the number counted when the chromosome is constrained to lie flat. In general, the number of secondary twists in the native, supertwisted chromosome is expected to be the "normal" Watson–Crick winding number, meaning a single 10-base-pair helical twist for every 34 Å of DNA length. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
Wr, called "writhe," is the number of superhelical twists. Since biological circular DNA is usually underwound, Lk will generally be less than Tw, which means that Wr will typically be negative. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
If DNA is underwound, it will be under strain, exactly as a metal spring is strained when forcefully unwound, and that the appearance of supertwists will allow the chromosome to relieve its strain by taking on negative supertwists, which correct the secondary underwinding in accordance with the topology equation above. The topology equation shows that there is a one-to-one relationship between changes in Tw and Wr. For example, if a secondary "Watson–Crick" twist is removed, then a right-handed supertwist must have been removed simultaneously (or, if the chromosome is relaxed, with no supertwists, then a left-handed supertwist must be added). | https://en.wikipedia.org/wiki/Supercoiled_DNA |
The change in the linking number, ΔLk, is the actual number of turns in the plasmid/molecule, Lk, minus the number of turns in the relaxed plasmid/molecule Lko: Δ L k = L k − L k o {\displaystyle \Delta Lk=Lk-Lk_{o}} If the DNA is negatively supercoiled, Δ L k < 0 {\displaystyle \Delta Lk<0} . The negative supercoiling implies that the DNA is underwound. A standard expression independent of the molecule size is the "specific linking difference" or "superhelical density" denoted σ, which represents the number of turns added or removed relative to the total number of turns in the relaxed molecule/plasmid, indicating the level of supercoiling. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
σ = Δ L k / L k o {\displaystyle \sigma =\Delta {Lk/Lk_{o}}} The Gibbs free energy associated with the coiling is given by the equation below Δ G / N = 10 R T σ 2 {\displaystyle {\Delta G/N=10RT\sigma ^{2}}} The difference in Gibbs free energy between the supercoiled circular DNA and uncoiled circular DNA with N > 2000 bp is approximated by: Δ G / N = 700 Kcal / b p ∗ ( Δ L k / N ) {\displaystyle \Delta G/N=700\,{\text{Kcal}}/bp*(\Delta Lk/N)} or, 16 cal/bp. Since the linking number L of supercoiled DNA is the number of times the two strands are intertwined (and both strands remain covalently intact), L cannot change. The reference state (or parameter) L0 of a circular DNA duplex is its relaxed state. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
In this state, its writhe W = 0. Since L = T + W, in a relaxed state T = L. Thus, if we have a 400 bp relaxed circular DNA duplex, L ~ 40 (assuming ~10 bp per turn in B-DNA). Then T ~ 40. Positively supercoiling: T = 0, W = 0, then L = 0 T = +3, W = 0, then L = +3 T = +2, W = +1, then L = +3 Negatively supercoiling: T = 0, W = 0, then L = 0 T = -3, W = 0, then L = -3 T = -2, W = -1, then L = -3Negative supercoils favor local unwinding of the DNA, allowing processes such as transcription, DNA replication, and recombination. Negative supercoiling is also thought to favour the transition between B-DNA and Z-DNA, and moderate the interactions of DNA binding proteins involved in gene regulation. | https://en.wikipedia.org/wiki/Supercoiled_DNA |
In nature, controlling or the avoidance of pathogens is an essential fitness strategy because disease-causing agents are ever-present. Pathogens reproduce rapidly at the expense of their hosts' fitness, this creates a coevolutionary arms race between pathogen transmission and host avoidance. For a pathogen to move to a new host, it must exploit regions of the body that serve as points of contact between current and future hosts such as the mouth, the skin, the anus and the genitals. To avoid the cost of infection, organisms require counteradaptations to prevent pathogen transmission, by defending entry points such as the mouth and skin and avoiding other individual's exit points and the substances exiting these points such as feces and sneeze droplets. | https://en.wikipedia.org/wiki/Pathogen_avoidance |
Pathogen avoidance provides the first line of defense by physically avoiding conspecifics, other species, objects or locations that could increase vulnerability to pathogens.The pathogen avoidance theory of disgust predicts that behavior that reduces contact with pathogens, will have been under strong selection throughout the evolution of free-living organisms and should be prevalent throughout the Animalia kingdom. Compared to the alternative, facing the infectious threat, avoidance likely provides a reduction in exposure to pathogens and in energetic costs associated with activation of the physiological immune response. These behaviors are found throughout the animal literature, particularly amongst social animals. | https://en.wikipedia.org/wiki/Pathogen_avoidance |
In nature, cytochalasin B is involved in fungal virulence, food spoilage and the maintenance of the symbiosis between host and symbiont. | https://en.wikipedia.org/wiki/Cytochalasin_B |
In nature, denitrification can take place in both terrestrial and marine ecosystems. Typically, denitrification occurs in anoxic environments, where the concentration of dissolved and freely available oxygen is depleted. In these areas, nitrate (NO3−) or nitrite (NO2−) can be used as a substitute terminal electron acceptor instead of oxygen (O2), a more energetically favourable electron acceptor. Terminal electron acceptor is a compound that gets reduced in the reaction by receiving electrons. | https://en.wikipedia.org/wiki/Denitrification |
Examples of anoxic environments can include soils, groundwater, wetlands, oil reservoirs, poorly ventilated corners of the ocean and seafloor sediments. Furthermore, denitrification can occur in oxic environments as well. High activity of denitrifiers can be observed in the intertidal zones, where the tidal cycles cause fluctuations of oxygen concentration in sandy coastal sediments. | https://en.wikipedia.org/wiki/Denitrification |
For example, the bacterial species Paracoccus denitrificans engages in denitrification under both oxic and anoxic conditions simultaneously. Upon oxygen exposure, the bacteria is able to utilize nitrous oxide reductase, an enzyme that catalyzes the last step of denitrification. Aerobic denitrifiers are mainly Gram-negative bacteria in the phylum Proteobacteria. | https://en.wikipedia.org/wiki/Denitrification |
Enzymes NapAB, NirS, NirK and NosZ are located in the periplasm, a wide space bordered by the cytoplasmic and the outer membrane in Gram-negative bacteria.Denitrification can lead to a condition called isotopic fractionation in the soil environment. The two stable isotopes of nitrogen, 14N and 15N are both found in the sediment profiles. The lighter isotope of nitrogen, 14N, is preferred during denitrification, leaving the heavier nitrogen isotope, 15N, in the residual matter. This selectivity leads to the enrichment of 14N in the biomass compared to 15N. Moreover, the relative abundance of 14N can be analyzed to distinguish denitrification apart from other processes in nature. | https://en.wikipedia.org/wiki/Denitrification |
In nature, enzymes called Baeyer-Villiger monooxygenases (BVMOs) perform the oxidation analogously to the chemical reaction. To facilitate this chemistry, BVMOs contain a flavin adenine dinucleotide (FAD) cofactor. In the catalytic cycle (see figure on the right), the cellular redox equivalent NADPH first reduces the cofactor, which allows it subsequently to react with molecular oxygen. The resulting peroxyflavin is the catalytic entity oxygenating the substrate, and theoretical studies suggest that the reaction proceeds through the same Criegee intermediate as observed in the chemical reaction. | https://en.wikipedia.org/wiki/Baeyer-Villiger_oxidation |
After the rearrangement step forming the ester product, a hydroxyflavin remains, which spontaneously eliminates water to form oxidized flavin, thereby closing the catalytic cycle. BVMOs are closely related to the flavin-containing monooxygenases (FMOs), enzymes that also occur in the human body, functioning within the frontline metabolic detoxification system of the liver along the cytochrome P450 monooxygenases. Human FMO5 was in fact shown to be able to catalyse Baeyer-Villiger reactions, indicating that the reaction may occur in the human body as well.BVMOs have been widely studied due to their potential as biocatalysts, that is, for an application in organic synthesis. | https://en.wikipedia.org/wiki/Baeyer-Villiger_oxidation |
Considering the environmental concerns for most of the chemical catalysts, the use of enzymes is considered a greener alternative. BVMOs in particular are interesting for application because they fulfil a range of criteria typically sought for in biocatalysis: besides their ability to catalyse a synthetically useful reaction, some natural homologs were found to have a very large substrate scope (i.e. their reactivity was not restricted to a single compound, as often assumed in enzyme catalysis), they can be easily produced on a large scale, and because the three-dimensional structure of many BVMOs has been determined, enzyme engineering could be applied to produce variants with improved thermostability and/or reactivity. Another advantage of using enzymes for the reaction is their frequently observed regio- and enantioselectivity, owed to the steric control of substrate orientation during catalysis within the enzyme's active site. | https://en.wikipedia.org/wiki/Baeyer-Villiger_oxidation |
In nature, formic acid is found in most ants and in stingless bees of the genus Oxytrigona. Wood ants from the genus Formica can spray formic acid on their prey or to defend the nest. The puss moth caterpillar (Cerura vinula) will spray it as well when threatened by predators. | https://en.wikipedia.org/wiki/HCOOH |
It is also found in the trichomes of stinging nettle (Urtica dioica). Apart from that, this acid is incorporated in many fruits such as pineapple (0.21mg per 100g), apple (2mg per 100g) and kiwi (1mg per 100g), as well as in many vegetables, namely onion (45mg per 100g), eggplant (1.34 mg per 100g) and, in extremely low concentrations, cucumber (0.11mg per 100g). Formic acid is a naturally occurring component of the atmosphere primarily due to forest emissions. | https://en.wikipedia.org/wiki/HCOOH |
In nature, free field conditions occur only when sound reflections from the floor can be ignored, e.g. in new snow in a field, or approximately at good sound-absorbing floors (deciduous, dry sand, etc.) Free field conditions can be artificially produced in anechoic chambers. In particular, free field conditions play a major role in acoustic measurements and sound perception experiments as results are isolated from room reflections. With voice and sound recordings, one often seeks a condition free from sound reflections similar to a free field, even when during post-processing specifically desired spatial impression will be added, because this is not distorted by any sound reflections of the recording room. In the simple example shown in Figure 1, a singular sound source emits sound evenly and spherically with no obstructions. | https://en.wikipedia.org/wiki/Free_field_(acoustics) |
In nature, free oxygen is produced by the light-driven splitting of water during oxygenic photosynthesis. According to some estimates, green algae and cyanobacteria in marine environments provide about 70% of the free oxygen produced on Earth, and the rest is produced by terrestrial plants. Other estimates of the oceanic contribution to atmospheric oxygen are higher, while some estimates are lower, suggesting oceans produce ~45% of Earth's atmospheric oxygen each year.A simplified overall formula for photosynthesis is 6 CO2 + 6 H2O + photons → C6H12O6 + 6 O2or simply carbon dioxide + water + sunlight → glucose + dioxygenPhotolytic oxygen evolution occurs in the thylakoid membranes of photosynthetic organisms and requires the energy of four photons. Many steps are involved, but the result is the formation of a proton gradient across the thylakoid membrane, which is used to synthesize adenosine triphosphate (ATP) via photophosphorylation. | https://en.wikipedia.org/wiki/Medical_oxygen |
The O2 remaining (after production of the water molecule) is released into the atmosphere.Oxygen is used in mitochondria in the generation of ATP during oxidative phosphorylation. The reaction for aerobic respiration is essentially the reverse of photosynthesis and is simplified as C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 2880 kJ/molIn vertebrates, O2 diffuses through membranes in the lungs and into red blood cells. Hemoglobin binds O2, changing color from bluish red to bright red (CO2 is released from another part of hemoglobin through the Bohr effect). | https://en.wikipedia.org/wiki/Medical_oxygen |
Other animals use hemocyanin (molluscs and some arthropods) or hemerythrin (spiders and lobsters). A liter of blood can dissolve 200 cm3 of O2.Until the discovery of anaerobic metazoa, oxygen was thought to be a requirement for all complex life.Reactive oxygen species, such as superoxide ion (O−2) and hydrogen peroxide (H2O2), are reactive by-products of oxygen use in organisms. Parts of the immune system of higher organisms create peroxide, superoxide, and singlet oxygen to destroy invading microbes. | https://en.wikipedia.org/wiki/Medical_oxygen |
Reactive oxygen species also play an important role in the hypersensitive response of plants against pathogen attack. Oxygen is damaging to obligately anaerobic organisms, which were the dominant form of early life on Earth until O2 began to accumulate in the atmosphere about 2.5 billion years ago during the Great Oxygenation Event, about a billion years after the first appearance of these organisms.An adult human at rest inhales 1.8 to 2.4 grams of oxygen per minute. This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. | https://en.wikipedia.org/wiki/Medical_oxygen |
In nature, free oxygen is produced by the light-driven splitting of water during oxygenic photosynthesis. Green algae and cyanobacteria in marine environments provide about 70% of the free oxygen produced on earth. The remainder is produced by terrestrial plants, although, for example, almost all oxygen produced in tropical forests is consumed by organisms living there.A simplified overall formula for photosynthesis is: 6CO2 + 6H2O + photons → C6H12O6 + 6O2(or simply carbon dioxide + water + sunlight → glucose + oxygen) Photolytic oxygen evolution during photosynthesis occurs via the light-dependent oxidation of water to molecular oxygen and can be written as the following simplified chemical reaction: 2H2O → 4e− + 4H+ + O2The reaction occurs in the thylakoid membranes of cyanobacteria as well as algal and plant chloroplasts and requires the energy of four photons. | https://en.wikipedia.org/wiki/Dioxygen_in_biological_reactions |
The electrons extracted from the water molecules transfer to the electron-deficient high-energy state P680+ of the P680 pigment of Photosystem II, which have been removed into an electron transport chain after light-dependent excitation and a series of redox reactions onto plastoquinone. Photosystem II therefore has also been referred to as water-plastoquinone oxido-reductase. The protons split off from the water molecules are released into the thylakoid lumen, thus contributing to the generation of a proton gradient across the thylakoid membrane. | https://en.wikipedia.org/wiki/Dioxygen_in_biological_reactions |
This proton gradient is the driving force for ATP synthesis via photophosphorylation and couples the absorption of light energy and photolysis of water to the creation of chemical energy during photosynthesis. The O2 remaining after oxidation of the water molecule is released into the atmosphere. Water oxidation is catalyzed by a manganese-containing enzyme complex known as the oxygen evolving complex (OEC) or water-splitting complex found associated with the lumenal side of thylakoid membranes. Manganese is an important cofactor, and calcium and chloride are also required for the reaction to occur. | https://en.wikipedia.org/wiki/Dioxygen_in_biological_reactions |
In nature, heparin is a polymer of varying chain size. Unfractionated heparin (UFH) as a pharmaceutical is heparin that has not been fractionated to sequester the fraction of molecules with low molecular weight. In contrast, low-molecular-weight heparin (LMWH) has undergone fractionation for the purpose of making its pharmacodynamics more predictable. Often either UFH or LMWH can be used; in some situations one or the other is preferable. | https://en.wikipedia.org/wiki/Heparin |
In nature, hydroxytyrosol is generated by the hydrolysis of oleuropein that occurs during olive ripening. Oleuropein accumulates in olive leaves and fruit as a defense mechanism against pathogens and herbivores. During olive ripening or when the olive tissue is damaged by pathogens, herbivores, or mechanical damage, the enzyme β-glucosidase catalyzes hydroxytyrosol synthesis via hydrolysis from oleuropein. | https://en.wikipedia.org/wiki/Hydroxytyrosol |
In nature, iron, copper, lead, nickel, and other metals are found in impure states called ores, often oxidized and mixed in with silicates of other metals. During smelting, when the ore is exposed to high temperatures, these impurities are separated from the molten metal and can be removed. Slag is the collection of compounds that are removed. In many smelting processes, oxides are introduced to control the slag chemistry, assisting in the removal of impurities and protecting the furnace refractory lining from excessive wear. | https://en.wikipedia.org/wiki/Basic_slag |
In this case, the slag is termed synthetic. A good example is steelmaking slag: quicklime (CaO) and magnesite (MgCO3) are introduced for refractory protection, neutralizing the alumina and silica separated from the metal, and assisting in the removal of sulfur and phosphorus from the steel.As a co-product of steelmaking, slag is typically produced either through the blast furnace - oxygen converter route or the electric arc furnace - ladle furnace route. To flux the silica produced during steelmaking, limestone and/or dolomite are added, as well as other types of slag conditioners such as calcium aluminate or fluorspar. | https://en.wikipedia.org/wiki/Basic_slag |
In nature, limonene is formed from geranyl pyrophosphate, via cyclization of a neryl carbocation or its equivalent as shown. The final step involves loss of a proton from the cation to form the alkene. The most widely practiced conversion of limonene is to carvone. The three-step reaction begins with the regioselective addition of nitrosyl chloride across the trisubstituted double bond. This species is then converted to the oxime with a base, and the hydroxylamine is removed to give the ketone-containing carvone. | https://en.wikipedia.org/wiki/Limonene |
In nature, many blue phenomena arise from structural colouration, the result of interference between reflections from two or more surfaces of thin films, combined with refraction as light enters and exits such films. The geometry then determines that at certain angles, the light reflected from both surfaces interferes constructively, while at other angles, the light interferes destructively. Diverse colours therefore appear despite the absence of colourants. | https://en.wikipedia.org/wiki/Blue_color |
In nature, methoxy groups are found on nucleosides that have been subjected to 2′-O-methylation, for example in variations of the 5′-cap structure known as cap-1 and cap-2. They are also common substituents in O-methylated flavonoids, whose formation is catalyzed by O-methyltransferases that act on phenols, such as catechol-O-methyl transferase (COMT). Many natural products in plants, such as lignins, are generated via catalysis by caffeoyl-CoA O-methyltransferase. | https://en.wikipedia.org/wiki/Methoxy_group |
In nature, mice are usually herbivores, consuming a wide range of fruit or grain. However, in laboratory studies it is usually necessary to avoid biological variation and to achieve this, laboratory mice are almost always fed only commercial pelleted mouse feed. Food intake is approximately 15 g (0.53 oz) per 100 g (3.5 oz) of body weight per day; water intake is approximately 15 ml (0.53 imp fl oz; 0.51 US fl oz) per 100 g of body weight per day. | https://en.wikipedia.org/wiki/Laboratory_mice |
In nature, networks rarely appear in isolation. They are typically elements in larger systems and can have non-trivial effects on one another. For example, infrastructure networks exhibit interdependency to a large degree. The power stations which form the nodes of the power grid require fuel delivered via a network of roads or pipes and are also controlled via the nodes of communications network. | https://en.wikipedia.org/wiki/Interdependent_networks |
Though the transportation network does not depend on the power network to function, the communications network does. Thus the deactivation of a critical number of nodes in either the power network or the communication network can lead to a series of cascading failures across the system with potentially catastrophic repercussions. If the two networks were treated in isolation, this important feedback effect would not be seen and predictions of network robustness would be greatly overestimated. | https://en.wikipedia.org/wiki/Interdependent_networks |
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