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In nature, organisms are neither distributed uniformly nor at random, forming instead some sort of spatial pattern. This is due to various energy inputs, disturbances, and species interactions that result in spatially patchy structures or gradients. This spatial variance in the environment creates diversity in communities of organisms, as well as in the variety of the observed biological and ecological events. The type of spatial arrangement present may suggest certain interactions within and between species, such as competition, predation, and reproduction. | https://en.wikipedia.org/wiki/Spatial_ecology |
On the other hand, certain spatial patterns may also rule out specific ecological theories previously thought to be true.Although spatial ecology deals with spatial patterns, it is usually based on observational data rather than on an existing model. This is because nature rarely follows set expected order. To properly research a spatial pattern or population, the spatial extent to which it occurs must be detected. | https://en.wikipedia.org/wiki/Spatial_ecology |
Ideally, this would be accomplished beforehand via a benchmark spatial survey, which would determine whether the pattern or process is on a local, regional, or global scale. This is rare in actual field research, however, due to the lack of time and funding, as well as the ever-changing nature of such widely-studied organisms such as insects and wildlife. With detailed information about a species' life-stages, dynamics, demography, movement, behavior, etc., models of spatial pattern may be developed to estimate and predict events in unsampled locations. | https://en.wikipedia.org/wiki/Spatial_ecology |
In nature, proanthocyanidins serve among other chemical and induced defense mechanisms against plant pathogens and predators, such as occurs in strawberries. | https://en.wikipedia.org/wiki/Proanthocyanidin |
In nature, pyruvate oxidase employs two cofactors thiamine pyrophosphate (ThDP) and Flavin adenine dinucleotide (FAD) to catalyze a conversion of pyruvate to acetyl phosphate. First, ThDP mediates a decarboxylation of pyruvate and generates an active aldehyde as a product. The aldehyde is then oxidized by FAD and is subsequently attacked by phosphate to yield acetyl phosphate. | https://en.wikipedia.org/wiki/Supramolecular_catalysis |
Diederich and coworkers mimicked this system with a supramolecular catalyst based on cyclophane. The catalyst has thiazolium ion, a reactive part of ThDP and flavin, a bare-bones core of FAD, in close proximity and near the substrate binding site. The catalytic cycle is almost the same as that in nature, except the substrate is an aromatic aldehyde rather than pyruvate. | https://en.wikipedia.org/wiki/Supramolecular_catalysis |
First, the catalyst binds the substrate within its cyclophane ring. Then, it uses thiazolium ion to condense with the substrate generating an active aldehyde. This aldehyde is oxidized by flavin and then attacked by methanol to yield a methyl ester. | https://en.wikipedia.org/wiki/Supramolecular_catalysis |
In nature, scandium is found exclusively as the isotope 45Sc, which has a nuclear spin of 7/2; this is its only stable isotope. Twenty-five radioisotopes have been characterized with the most stable being 46Sc, which has a half-life of 83.8 days; 47Sc, 3.35 days; the positron emitter 44Sc, 4 hours; and 48Sc, 43.7 hours. All of the remaining radioactive isotopes have half-lives less than 4 hours, and the majority of these have half-lives less than 2 minutes. | https://en.wikipedia.org/wiki/Scandium |
This element also has five nuclear isomers, with the most stable being 44m2Sc (t1/2 = 58.6 h).The known isotopes of scandium range from 36Sc to 60Sc. The primary decay mode at masses lower than the only stable isotope, 45Sc, is electron capture, and the primary mode at masses above it is beta emission. The primary decay products at atomic weights below 45Sc are calcium isotopes and the primary products from higher atomic weights are titanium isotopes. | https://en.wikipedia.org/wiki/Scandium |
In nature, self-assembled gyroid structures are found in certain surfactant or lipid mesophases and block copolymers. In a typical A-B diblock copolymer phase diagram, the gyroid phase can be formed at intermediate volume fractions between the lamellar and cylindrical phases. In A-B-C block copolymers, the double and alternating-gyroid phases can be formed. Such self-assembled polymer structures have found applications in experimental supercapacitors, solar cells photocatalysts, and nanoporous membranes. | https://en.wikipedia.org/wiki/Gyroid |
Gyroid membrane structures are occasionally found inside cells. Gyroid structures have photonic band gaps that make them potential photonic crystals. Single gyroid photonic crystals have been observed in biological structural coloration such as butterfly wing scales and bird feathers, inspiring work on biomimetic materials. | https://en.wikipedia.org/wiki/Gyroid |
The gyroid mitochondrial membranes found in the retinal cone cells of certain tree shrew species present a unique structure which may have an optical function.In 2017, MIT researchers studied the possibility of using the gyroid shape to turn bi-dimensional materials, such as graphene, into a three-dimensional structural material with low density, yet high tensile strength.Researchers from Cambridge University have shown the controlled chemical vapor deposition of sub–60 nm graphene gyroids. These interwoven structures are one of the smallest free-standing graphene 3D structures. They are conductive, mechanically stable, and easily transferable, and are of interest for a wide range of applications.The gyroid pattern has also found use in 3D printing for lightweight internal structures, due to its high strength, combined with speed and ease of printing using an FDM 3D printer.In an in silico study, researchers from the university hospital Charité in Berlin investigated the potential of gyroid architecture when used as a scaffold in a large bone defect in a rat femur. When comparing the regenerated bone within a gyroid scaffold compared to a traditional strut-like scaffold, they found that gyroid scaffolds led to less bone formation and attributed this reduced bone formation to the gyroid architecture hindering cell penetration. | https://en.wikipedia.org/wiki/Gyroid |
In nature, species do not evolve in isolation but in large networks of interacting species. One of the main goals in evolutionary ecology is to disentangle the evolutionary mechanisms that shape and are shaped by patterns of interaction between species. A particularly important question concerns how coevolution, the reciprocal evolutionary change in local populations of interacting species driven by natural selection, is shaped by the architecture of food webs, plant-animal mutualistic networks, and host-parasite communities. The concept of diffuse coevolution, where adaptation is in response to a suite of biotic interactions, was the first step towards a framework unifying relevant theories in community ecology and coevolution. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
Understanding how individual interactions within networks influence coevolution, and conversely how coevolution influences the overall structure of networks, requires an appreciation for how pair-wise interactions change due to their broader community contexts as well as how this community context shapes selective pressures. Accordingly, research is now focusing on how reciprocal selection influences and is embedded within the structure of multispecies interactive webs, not only on particular species in isolation.Coevolution in a community context can be addressed theoretically via mathematical modeling and simulation, by looking at ancient footprints of evolutionary history via ecological patterns that persist and are observable today, and by performing laboratory experiments with microorganisms. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
In spite of the long time scales involved and the substantial effort that is necessary to isolate and quantify samples, the latter approach of testing biological evolution in the lab has been successful over the last two decades. However, studying the evolution of interspecific interactions, which involves dealing with more complex webs of multiple interacting species, has proven to be a much more difficult challenge. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
A meta-analysis of host-phage interaction networks, carried out by Weitz and his team, found a striking statistical structure to the patterns of infection and resistance across a wide variety of environments and methods from which the hosts and phage were obtained. However, the ecological mechanisms and evolutionary processes responsible have yet to be unraveled. Digital ecological networks enable the direct, comprehensive, and real time observation of evolving ecological interactions between antagonistic and/or mutualistic digital organisms that are difficult to study in nature. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
Research using self-replicating computer programs can help us understand how coevolution shapes the emergence and diversification of coevolving species interaction networks and, in turn, how changes in the overall structure of the web (e.g., through extinction of taxa or the introduction of invasive species) affect the evolution of a given species. Studying the evolution of species interaction networks in these artificial evolving systems also contributes to the development of the field, while overcoming limitations evolutionary biologists may face. For example, laboratory studies have shown that historical contingency can enable or impede the outcome of the interactions between bacteria and phage, depending on the order in which mutations occur: the phage often, but not always, evolve the ability to infect a novel host. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
Therefore, in order to obtain statistical power for predicting such outcomes of the coevolutionary process, experiments require a high level of replication. This stochastic nature of the evolutionary process was exemplified by Stephen Jay Gould's inquiry ("What would happen if the tape of the history of life were rewound and replayed?") Because of their ease in scalability and replication, evolving digital ecological networks open the door to experiments that incorporate this approach of replaying the tape of life. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
Such experiments allow researchers to quantify the role of historical contingency and repeatability in network evolution, enabling predictions about the architecture and dynamics of large networks of interacting species. The inclusion of ecological interactions in digital systems enables new research avenues: investigations using self-replicating computer programs complement laboratory efforts by broadening the breadth of viable experiments focused on the emergence and diversification of coevolving interactions in complex communities. This cross-disciplinary research program provides fertile grounds for new collaborations between computer scientists and evolutionary biologists. | https://en.wikipedia.org/wiki/Evolving_digital_ecological_network |
In nature, the false percula clownfish is hosted by Heteractis magnifica and Stichodactyla gigantea. However, in captivity in a reef aquarium, the false percula is hosted by other species of anemone, including Entacmaea quadricolor. In addition, clownfish may adopt a surrogate host as opposed to an anemone, such as Euphyllia divisa, xenia coral, etc. | https://en.wikipedia.org/wiki/Common_clownfish |
In nature, the incorporation of a deoxyribonucleoside triphosphate (dNTP) into a growing DNA strand involves the formation of a covalent bond and the release of pyrophosphate and a positively charged hydrogen ion. A dNTP will only be incorporated if it is complementary to the leading unpaired template nucleotide. Ion semiconductor sequencing exploits these facts by determining if a hydrogen ion is released upon providing a single species of dNTP to the reaction. Microwells on a semiconductor chip that each contain many copies of one single-stranded template DNA molecule to be sequenced and DNA polymerase are sequentially flooded with unmodified A, C, G or T dNTP. | https://en.wikipedia.org/wiki/Ion_semiconductor_sequencing |
If an introduced dNTP is complementary to the next unpaired nucleotide on the template strand it is incorporated into the growing complementary strand by the DNA polymerase. If the introduced dNTP is not complementary there is no incorporation and no biochemical reaction. The hydrogen ion that is released in the reaction changes the pH of the solution, which is detected by an ISFET. The unattached dNTP molecules are washed out before the next cycle when a different dNTP species is introduced. | https://en.wikipedia.org/wiki/Ion_semiconductor_sequencing |
In nature, there are six different pathways where CO2 is fixed. Of these, the Wood–Ljungdahl pathway is the predominant sink in anaerobic conditions. Acetyl-CoA Synthase (ACS) and carbon monoxide dehydrogenase (CODH) are integral enzymes in this one pathway and can perform diverse reactions in the carbon cycle as a result. Because of this, the exact activity of these molecules has come under intense scrutiny over the past decade. | https://en.wikipedia.org/wiki/Acetyl-CoA_synthase |
In nature, there are very few organisms who can fly in such manner, making the phenomenon very rare. In the class Aves (birds), there is only one family, Trochilidae (hummingbirds) where the backward flying phenomenon can be found. In the class Insecta (insects), in the infraorder Anisoptera (dragonflies), genus Hemaris (bee hawk-moths) and order Diptera (true flies), species with this ability can be also found.There are also some species that don't use the traditional wing flapping mechanism to fly backwards. One such example is the Japanese flying squid, which uses a jet propulsion mechanism for backward flying. | https://en.wikipedia.org/wiki/Backward_flying |
In nature, there is a wide array of biominerals, ranging from iron oxide to strontium sulfate, with calcareous biominerals being particularly notable. However, the most taxonomically widespread biomineral is silica (SiO2·nH2O), being present in all eukaryotic supergroups. Notwithstanding, the degree of silicification can vary even between closely related taxa, from being found in composite structures with other biominerals (e.g., limpet teeth; to forming minor structures (e.g., ciliate granules; or being a major structural constituent of the organism. The most extreme degree of silicification is evident in the diatoms, where almost all species have an obligate requirement for silicon to complete cell wall formation and cell division. | https://en.wikipedia.org/wiki/Biomineralization |
Biogeochemically and ecologically, diatoms are the most important silicifiers in modern marine ecosystems, with radiolarians (polycystine and phaeodarian rhizarians), silicoflagellates (dictyochophyte and chrysophyte stramenopiles), and sponges with prominent roles as well. In contrast, the major silicifiers in terrestrial ecosystems are the land plants (embryophytes), with other silicifying groups (e.g., testate amoebae) having a minor role.Broadly, biomineralized structures evolve and diversify when the energetic cost of biomineral production is less than the expense of producing an equivalent organic structure. | https://en.wikipedia.org/wiki/Biomineralization |
The energetic costs of forming a silica structure from silicic acid are much less than forming the same volume from an organic structure (≈20-fold less than lignin or 10-fold less than polysaccharides like cellulose). Based on a structural model of biogenic silica, Lobel et al. (1996) identified by biochemical modeling a low-energy reaction pathway for nucleation and growth of silica. The combination of organic and inorganic components within biomineralized structures often results in enhanced properties compared to exclusively organic or inorganic materials. | https://en.wikipedia.org/wiki/Biomineralization |
With respect to biogenic silica, this can result in the production of much stronger structures, such as siliceous diatom frustules having the highest strength per unit density of any known biological material, or sponge spicules being many times more flexible than an equivalent structure made of pure silica. As a result, biogenic silica structures are used for support, feeding, predation defense and environmental protection as a component of cyst walls. Biogenic silica also has useful optical properties for light transmission and modulation in organisms as diverse as plants, diatoms, sponges, and molluscs. | https://en.wikipedia.org/wiki/Biomineralization |
There is also evidence that silicification is used as a detoxification response in snails and plants, biosilica has even been suggested to play a role as a pH buffer for the enzymatic activity of carbonic anhydrase, aiding the acquisition of inorganic carbon for photosynthesis. There are questions which have yet to be resolved, such as why some organisms biomineralize while others do not, and why is there such a diversity of biominerals besides silicon when silicon is so abundant, comprising 28% of the Earth's crust. The answer to these questions lies in the evolutionary interplay between biomineralization and geochemistry, and in the competitive interactions that have arisen from these dynamics. | https://en.wikipedia.org/wiki/Biomineralization |
Fundamentally whether an organism produces silica or not involves evolutionary trade-offs and competition between silicifiers themselves, and non-silicifying organisms (both those which use other biominerals, and non-mineralizing groups). Mathematical models and controlled experiments of resource competition in phytoplankton have demonstrated the rise to dominance of different algal species based on nutrient backgrounds in defined media. These have been part of fundamental studies in ecology. However, the vast diversity of organisms that thrive in a complex array of biotic and abiotic interactions in oceanic ecosystems are a challenge to such minimal models and experimental designs, whose parameterization and possible combinations, respectively, limit the interpretations that can be built on them. | https://en.wikipedia.org/wiki/Biomineralization |
In nature, unsaturated fatty acids generally have double bonds in cis configuration (with the adjacent C–C bonds on the same side) as opposed to trans. Nevertheless, trans fatty acids (TFAs) occur in small amounts in meat and milk of ruminants (such as cattle and sheep), typically 2–5% of total fat. Natural TFAs, which include conjugated linoleic acid (CLA) and vaccenic acid, originate in the rumen of these animals. CLA has two double bonds, one in the cis configuration and one in trans, which makes it simultaneously a cis- and a trans-fatty acid. | https://en.wikipedia.org/wiki/Dietary_fat |
Concerns about trans fatty acids in human diet were raised when they were found to be an unintentional byproduct of the partial hydrogenation of vegetable and fish oils. While these trans fatty acids (popularly called "trans fats") are edible, they have been implicated in many health problems. The hydrogenation process, invented and patented by Wilhelm Normann in 1902, made it possible to turn relatively cheap liquid fats such as whale or fish oil into more solid fats and to extend their shelf-life by preventing rancidification. | https://en.wikipedia.org/wiki/Dietary_fat |
(The source fat and the process were initially kept secret to avoid consumer distaste.) This process was widely adopted by the food industry in the early 1900s; first for the production of margarine, a replacement for butter and shortening, and eventually for various other fats used in snack food, packaged baked goods, and deep fried products.Full hydrogenation of a fat or oil produces a fully saturated fat. | https://en.wikipedia.org/wiki/Dietary_fat |
However, hydrogenation generally was interrupted before completion, to yield a fat product with specific melting point, hardness, and other properties. Partial hydrogenation turns some of the cis double bonds into trans bonds by an isomerization reaction. | https://en.wikipedia.org/wiki/Dietary_fat |
The trans configuration is favored because it is the lower energy form. This side reaction accounts for most of the trans fatty acids consumed today, by far. An analysis of some industrialized foods in 2006 found up to 30% "trans fats" in artificial shortening, 10% in breads and cake products, 8% in cookies and crackers, 4% in salty snacks, 7% in cake frostings and sweets, and 26% in margarine and other processed spreads. | https://en.wikipedia.org/wiki/Dietary_fat |
Another 2010 analysis however found only 0.2% of trans fats in margarine and other processed spreads. Up to 45% of the total fat in those foods containing man-made trans fats formed by partially hydrogenating plant fats may be trans fat. Baking shortenings, unless reformulated, contain around 30% trans fats compared to their total fats. | https://en.wikipedia.org/wiki/Dietary_fat |
High-fat dairy products such as butter contain about 4%. Margarines not reformulated to reduce trans fats may contain up to 15% trans fat by weight, but some reformulated ones are less than 1% trans fat. High levels of TFAs have been recorded in popular "fast food" meals. | https://en.wikipedia.org/wiki/Dietary_fat |
An analysis of samples of McDonald's French fries collected in 2004 and 2005 found that fries served in New York City contained twice as much trans fat as in Hungary, and 28 times as much as in Denmark, where trans fats are restricted. For Kentucky Fried Chicken products, the pattern was reversed: the Hungarian product containing twice the trans fat of the New York product. Even within the United States, there was variation, with fries in New York containing 30% more trans fat than those from Atlanta. | https://en.wikipedia.org/wiki/Dietary_fat |
In nature, uranium is found as uranium-238 (99.2742%) and uranium-235 (0.7204%). Isotope separation concentrates (enriches) the fissile uranium-235 for nuclear weapons and most nuclear power plants, except for gas cooled reactors and pressurised heavy water reactors. Most neutrons released by a fissioning atom of uranium-235 must impact other uranium-235 atoms to sustain the nuclear chain reaction. The concentration and amount of uranium-235 needed to achieve this is called a 'critical mass'. | https://en.wikipedia.org/wiki/Uranium_Processing |
To be considered 'enriched', the uranium-235 fraction should be between 3% and 5%. This process produces huge quantities of uranium that is depleted of uranium-235 and with a correspondingly increased fraction of uranium-238, called depleted uranium or 'DU'. To be considered 'depleted', the uranium-235 isotope concentration should be no more than 0.3%. | https://en.wikipedia.org/wiki/Uranium_Processing |
The price of uranium has risen since 2001, so enrichment tailings containing more than 0.35% uranium-235 are being considered for re-enrichment, driving the price of depleted uranium hexafluoride above $130 per kilogram in July 2007 from $5 in 2001.The gas centrifuge process, where gaseous uranium hexafluoride (UF6) is separated by the difference in molecular weight between 235UF6 and 238UF6 using high-speed centrifuges, is the cheapest and leading enrichment process. The gaseous diffusion process had been the leading method for enrichment and was used in the Manhattan Project. In this process, uranium hexafluoride is repeatedly diffused through a silver-zinc membrane, and the different isotopes of uranium are separated by diffusion rate (since uranium-238 is heavier it diffuses slightly slower than uranium-235). | https://en.wikipedia.org/wiki/Uranium_Processing |
The molecular laser isotope separation method employs a laser beam of precise energy to sever the bond between uranium-235 and fluorine. This leaves uranium-238 bonded to fluorine and allows uranium-235 metal to precipitate from the solution. An alternative laser method of enrichment is known as atomic vapor laser isotope separation (AVLIS) and employs visible tunable lasers such as dye lasers. | https://en.wikipedia.org/wiki/Uranium_Processing |
Another method used is liquid thermal diffusion.The only significant deviation from the 235U to 238U ratio in any known natural samples occurs in Oklo, Gabon, where natural nuclear fission reactors consumed some of the 235U some two billion years ago when the ratio of 235U to 238U was more akin to that of low enriched uranium allowing regular ("light") water to act as a neutron moderator akin to the process in humanmade light water reactors. The existence of such natural fission reactors which had been theoretically predicted beforehand was proven as the slight deviation of 235U concentration from the expected values were discovered during uranium enrichment in France. Subsequent investigations to rule out any nefarious human action (such as stealing of 235U) confirmed the theory by finding isotope ratios of common fission products (or rather their stable daughter nuclides) in line with the values expected for fission but deviating from the values expected for non-fission derived samples of those elements. | https://en.wikipedia.org/wiki/Uranium_Processing |
In nature, variations in isotopic ratios of trace metals on the order of a few tenths to several ‰ are observed within and across diverse environments spanning the geosphere, hydrosphere and biosphere. A complete understanding of all processes that fractionate trace metal isotopes is presently lacking, but in general, isotopes of trace metals are fractionated during various chemical and biological processes due to kinetic and equilibrium isotope effects. | https://en.wikipedia.org/wiki/Trace_metal_stable_isotope_biogeochemistry |
In nature, water cascading down a mountain will always follow the path of least resistance – the easiest route. In thinking, too, our minds tend to take the path of least resistance – those avenues most familiar to us. So doing, it is difficult to arrive at ideas new to us or to our competitors. SIT encourages an approach to the counter-intuitive path – the path of most resistance. | https://en.wikipedia.org/wiki/Systematic_inventive_thinking |
In nature, wings have evolved in insects, pterosaurs, dinosaurs (birds, Scansoriopterygidae), and mammals (bats) as a means of locomotion. Various species of penguins and other flighted or flightless water birds such as auks, cormorants, guillemots, shearwaters, eider and scoter ducks and diving petrels are avid swimmers, and use their wings to propel through water. | https://en.wikipedia.org/wiki/Wing |
In nature, yeast cells are found primarily on ripe fruits such as grapes (before maturation, grapes are almost free of yeasts). S. cerevisiae can also be found year-round in the bark of oak trees. Since S. cerevisiae is not airborne, it requires a vector to move.Queens of social wasps overwintering as adults (Vespa crabro and Polistes spp.) can harbor yeast cells from autumn to spring and transmit them to their progeny. The intestine of Polistes dominula, a social wasp, hosts S. cerevisiae strains as well as S. cerevisiae × S. paradoxus hybrids. Stefanini et al. (2016) showed that the intestine of Polistes dominula favors the mating of S. cerevisiae strains, both among themselves and with S. paradoxus cells by providing environmental conditions prompting cell sporulation and spores germination.The optimum temperature for growth of S. cerevisiae is 30–35 °C (86–95 °F). | https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae |
In nautical navigation the absolute bearing is the clockwise angle between north and an object observed from the vessel. If the north used as reference is the true geographical north then the bearing is a true bearing whereas if the reference used is magnetic north then the bearing is a magnetic bearing. An absolute bearing is measured with a bearing compass. The measurement of absolute bearings of fixed landmarks and other navigation aids is useful for the navigator because this information can be used on the nautical chart together with simple geometrical techniques to aid in determining the position of the vessel. | https://en.wikipedia.org/wiki/Bearing_angle |
A grid bearing (also known as grid azimuth) is measured in relation to the fixed horizontal reference plane of grid north, that is, using the direction northwards along the grid lines of the map projection as a reference point. A compass bearing, as in vehicle or marine navigation, is measured in relation to the magnetic compass of the navigator's vehicle or vessel (if aboard ship). It should be very close to the magnetic bearing. The difference between a magnetic bearing and a compass bearing is the deviation caused to the compass by ferrous metals and local magnetic fields generated by any variety of vehicle or shipboard sources (steel vehicle bodies/frames or vessel hulls, ignition systems, etc.) | https://en.wikipedia.org/wiki/Bearing_angle |
In nautical navigation the relative bearing of an object is the clockwise angle from the heading of the vessel to a straight line drawn from the observation station on the vessel to the object. The relative bearing is measured with a pelorus or other optical and electronic aids to navigation such as a periscope, sonar system, and radar systems. Since World War II, relative bearings of such diverse point sources have been and are calibrated carefully to one another. The United States Navy operates a special range off Puerto Rico and another on the west coast to perform such systems integration. | https://en.wikipedia.org/wiki/Absolute_bearing |
Relative bearings then serve as the baseline data for converting relative directional data into true bearings (N-S-E-W, relative to the Earth's true geography). By contrast, Compass bearings have a varying error factor at differing locations about the globe, and are less reliable than the compensated or true bearings. The measurement of relative bearings of fixed landmarks and other navigational aids is useful for the navigator because this information can be used on the nautical chart together with simple geometrical techniques to aid in determining the vessel's position, speed, course, etc. The measurement of relative bearings of other vessels and objects in movement is useful to the navigator in avoiding the danger of collision. | https://en.wikipedia.org/wiki/Absolute_bearing |
For example: The navigator on a ship observes a lighthouse when its relative bearing is 45° and again when it is 90°. He now knows that the distance from the ship to the lighthouse is equal to the distance travelled by the vessel between both observations. The pilot of a boat observes that the relative bearing of another boat is less than 180° and decreasing (that is, it is now closer to dead ahead than before). He now knows he will pass astern of the other boat. If the bearing were to remain constant, the two boats would be on a collision course. | https://en.wikipedia.org/wiki/Absolute_bearing |
In nautical settings, a stopper may refer to a length of rope that is belayed at one end with the other end attached to a tensioned main line using a friction hitch in order to tension the stopper and thereby slacken the portion of the tensioned main line behind the friction hitch. For example if a sheet becomes jammed on a winch while under sail, a "stopper" can be used to temporarily take the strain off the winch while the riding turn is cleared. Rolling hitch & similar friction hitches | https://en.wikipedia.org/wiki/Stopper_knot |
In nautical terminology, stowage is the amount of room available for stowing materials aboard a ship, tank or an airplane. In container shipping, stowage planning refers to the arrangement of containers on board a container vessel. The stowage of a container ship involves different objectives, such as to optimize the available space and prevent damage to the goods, and more importantly, to minimize the time the vessel spends at the port terminal. | https://en.wikipedia.org/wiki/Stowage |
Containers will be arranged depending on their destinations (those going to the first port calls in the schedule will be placed on top), cargo weight (lighter containers are stored on top of heavier ones), cargo nature (dangerous goods containers normally are placed at the end of ship, and on upper deck to minimize the loss, in case of fire or leakage), etc.In the past, this process was done by the ship's captain, merely based on his experience. Today, it has become more automated with optimization software. == References == | https://en.wikipedia.org/wiki/Stowage |
In nautical terms, the word sound is used to describe the process of determining the depth of water in a tank or under a ship. Tanks are sounded to determine if they are full (for cargo tanks) or empty (to determine if a ship has been holed) and for other reasons. Soundings may also be taken of the water around a ship if it is in shallow water to aid in navigation. | https://en.wikipedia.org/wiki/Sound_(nautical) |
In nautical usage the term "sheet" is applied to a line or chain attached to the lower corners of a sail for the purpose of extension or change of direction. The connection in derivation with the root "shoot" is more clearly seen in "sheet-anchor", one that is kept in reserve, to be "shot" in case of emergency. | https://en.wikipedia.org/wiki/Jib_sheet |
In nautical use, any boat uses a specific flag of a specific Nation to indicate its organizational membership. The ensign is flown on a ship for that reason. The flag signifies the home port of the ship owner and that his tax is paid there for his income made with the ship. Flagging out always means that the relevant laws of the country apply on the ship like employment contracts, safety, stamp duty or value-added taxes.In most countries, especially in Europe and the countries of the Commonwealth of Nations, it is common for the ensign to display additional information as well. For example, whether it is a civil, state or military flag.Ensigns are usually at the stern flagstaff when in port, and may be shifted to a gaff (if available) or mast amidships when the ship is under way, becoming known as a steaming ensign.A boat flag is also often used as guest country flag and is flown on the boat when navigating in foreign waters or entering another country's port. | https://en.wikipedia.org/wiki/Ensign_(flag) |
In naval architecture an afterdeck or after deck, or sometimes the aftdeck, aft deck or a-deck, is the open deck area toward the stern or aft back part of a ship or boat. The afterdeck can be used for a number of different purposes. Not all ships have an afterdeck. In place of the afterdeck a ship may be built with a poop deck, that is a deck that forms the roof of a cabin built in the rear, or "aft", part of the superstructure of a ship. | https://en.wikipedia.org/wiki/Afterdeck |
A poop deck usually is higher up than an afterdeck. A ship may have its superstructure or aftercastle located in the stern and thus not have an afterdeck. The stern and afterdeck of a ship are usually more smooth and stable than the bow (front) of the ship in motion. A taffrail is the handrail around the open afterdeck or poop deck. On wooden sailing ships like man-of-war or East Indiaman the taffrail is usually a hand carved wood rail and often highly decorated. | https://en.wikipedia.org/wiki/Afterdeck |
In naval architecture and aerospace engineering, the fineness ratio is the ratio of the length of a body to its maximum width. Shapes that are short and wide have a low fineness ratio, those that are long and narrow have high fineness ratios. Aircraft that spend time at supersonic speeds, e.g. the Concorde, generally have high fineness ratios. At speeds below critical mach, one of the primary forms of drag is skin friction. | https://en.wikipedia.org/wiki/Fineness_ratio |
As the name implies, this is drag caused by the interaction of the airflow with the aircraft's skin. To minimize this drag, the aircraft should be designed to minimize the exposed skin area, or "wetted surface". One solution to this problem is constructing an "egg shaped" fuselage, for example as used on the home-built Questair Venture. | https://en.wikipedia.org/wiki/Fineness_ratio |
Theoretical ideal fineness ratios in subsonic aircraft fuselages are typically found at about 6:1, however this may be compromised by other design considerations such as seating or freight size requirements. Because a higher fineness fuselage can have reduced tail surfaces, this ideal ratio can practically be increased to 8:1.Most aircraft have fineness ratios significantly greater than this, however. This is often due to the competing need to place the tail control surfaces at the end of a longer moment arm to increase their effectiveness. | https://en.wikipedia.org/wiki/Fineness_ratio |
Reducing the length of the fuselage would require larger controls, which would offset the drag savings from using the ideal fineness ratio. An example of a high-performance design with an imperfect fineness ratio is the Lancair. In other cases, the designer is forced to use a non-ideal design due to outside factors such as seating arrangements or cargo pallet sizes. | https://en.wikipedia.org/wiki/Fineness_ratio |
Modern airliners often have fineness ratios much higher than ideal, a side effect of their cylindrical cross-section which is selected for strength, as well as providing a single width to simplify seating layout and air cargo handling. As an aircraft approaches the speed of sound, shock waves form on areas of greater curvature. These shock waves radiate away energy that the engines must supply, energy that does not go into making the aircraft go faster. | https://en.wikipedia.org/wiki/Fineness_ratio |
This appears to be a new form of drag—referred to as wave drag—which peaks at about three times the drag at speeds even slightly below the critical mach. In order to minimize the wave drag, the curvature of the aircraft should be kept to a minimum, which implies much higher fineness ratios. This is why high-speed aircraft have long pointed noses and tails, and cockpit canopies that are flush to the fuselage line. | https://en.wikipedia.org/wiki/Fineness_ratio |
More technically, the best possible performance for a supersonic design is typified by two "perfect shapes", the Sears-Haack body which is pointed at both ends, or the von Kármán ogive, which has a blunt tail. Examples of the latter design include the Concorde, F-104 Starfighter and XB-70 Valkyrie, although to some degree practically every post-World War II interceptor aircraft featured such a design. | https://en.wikipedia.org/wiki/Fineness_ratio |
Missile designers are even less interested in low-speed performance, and missiles generally have higher fineness ratios than most aircraft. The introduction of aircraft with higher fineness ratios also introduced a new form of instability, inertial coupling. As the engines and cockpit moved away from the aircraft's center of mass, the roll inertia of these masses grew to be able to overwhelm the power of the aerodynamic surfaces. A variety of methods are used to combat this effect, including oversized controls and stability augmentation systems. | https://en.wikipedia.org/wiki/Fineness_ratio |
In naval architecture, a poop deck is a deck that forms the roof of a cabin built in the rear, or "aft", part of the superstructure of a ship.The name originates from the French word for stern, la poupe, from Latin puppis. Thus the poop deck is technically a stern deck, which in sailing ships was usually elevated as the roof of the stern or "after" cabin, also known as the "poop cabin" (or simply the poop). On sailing ships, the helmsman would steer the craft from the quarterdeck, immediately in front of the poop deck. At the stern, the poop deck provides an elevated position ideal for observation. While the main purpose of the poop is adding buoyancy to the aft, on a sailing ship the cabin was also used as an accommodation for the shipmaster and officers.On modern, motorized warships, the ship functions which were once carried out on the poop deck have been moved to the bridge, usually located in a superstructure. | https://en.wikipedia.org/wiki/Poop_Deck |
In naval architecture, sill also refers to the lower horizontal plate (frame) height, above which doors and access opening are fixed. | https://en.wikipedia.org/wiki/Sill_plate |
In naval architecture, the term transom has two meanings. First, it can be any of the individual beams that run side-to-side or "athwart" the hull at any point abaft the fashion timber; second, it can refer specifically to the flat or slightly curved surface that is the very back panel of a transom stern. In this sense, a transom stern is the product of the use of a series of transoms, and hence the two terms have blended. The stern of a classical sailing ship housed the captain's quarters and became increasingly large and elaborate between the 15th and 18th centuries, especially in the baroque era, when such wedding-cake-like structures became so heavy that crews sometimes threw the decoration overboard rather than be burdened with its useless weight. | https://en.wikipedia.org/wiki/Transom_stern |
Until a new form of stern appeared in the 19th century, the transom stern was a floating house—and required just as many timbers, walls, windows, and frames. The stern frame provided the foundational structure of the transom stern, and was composed of the sternpost, wing transom, and fashion piece.Abaft the fashion timber, the transom stern was composed of two different kinds of timbers: Transoms – These timbers extend across the low parts of the hull near the rudder, and are secured (notched and/or bolted) to the sternpost. The transom located at the base of the stern, and the uppermost of the main transoms, was typically called the wing transom; the principal transom below this and level with the lower deck was called the deck transom; between these two were a series of filling transoms. | https://en.wikipedia.org/wiki/Transom_stern |
If the stern had transoms above the wing transom, they would no longer be affixed to the sternpost. The first of these might be called a counter transom; next up was the window sill transom; above that, the spar deck transom. | https://en.wikipedia.org/wiki/Transom_stern |
The larger the vessel, the more numerous and wider the transoms required to support its stern. Stern timbers (also called stern frames) – These timbers are mounted vertically in a series; each timber typically rests or "steps" on the wing transom and then stretches out (aft) and upward. Those not reaching all the way to the taffrail are called short stern timbers, while those that do are called long stern timbers. | https://en.wikipedia.org/wiki/Transom_stern |
The two outermost of these timbers, located at the corners of the stern, are called the side-counter timbers or outer stern timbers. It is the stern timbers collectively which determine the backward slope of the square stern, called its rake – that is, if the stern timbers end up producing a final transom that falls vertically to the water, this is considered a transom with no rake; if the stern timbers produce a stern with some degree of slope; such a stern is considered a raked stern.The flat surface of any transom stern may begin either at or above the waterline of the vessel. The geometric line which stretches from the wing transom to the archboard is called the counter; a large vessel may have two such counters, called a lower counter and a second or upper counter. The lower counter stretches from directly above the wing transom to the lower counter rail, and the upper counter from the lower counter rail to the upper counter rail, immediately under the stern's lowest set of windows (which in naval parlance were called "lights"). | https://en.wikipedia.org/wiki/Transom_stern |
In naval battles of the 1890s the decisive weapon was the medium-calibre, typically 6-inch (152 mm), quick-firing gun firing at relatively short range; at the Battle of the Yalu River in 1894, the victorious Japanese did not commence firing until the range had closed to 4,300 yards (3,900 m), and most of the fighting occurred at 2,200 yards (2,000 m). At these ranges, lighter guns had good accuracy, and their high rate of fire delivered high volumes of ordnance on the target, known as the "hail of fire". Naval gunnery was too inaccurate to hit targets at a longer range.By the early 20th century, British and American admirals expected future battleships would engage at longer distances. Newer models of torpedo had longer ranges. | https://en.wikipedia.org/wiki/Dreadnought_battleship |
For instance, in 1903, the US Navy ordered a design of torpedo effective to 4,000 yards (3,700 m). Both British and American admirals concluded that they needed to engage the enemy at longer ranges. In 1900, Admiral Fisher, commanding the Royal Navy Mediterranean Fleet, ordered gunnery practice with 6-inch guns at 6,000 yards (5,500 m). | https://en.wikipedia.org/wiki/Dreadnought_battleship |
By 1904 the US Naval War College was considering the effects on battleship tactics of torpedoes with a range of 7,000 to 8,000 yards (6,400 to 7,300 m).The range of light and medium-calibre guns was limited, and accuracy declined badly at longer range. At longer ranges the advantage of a high rate of fire decreased; accurate shooting depended on spotting the shell-splashes of the previous salvo, which limited the optimum rate of fire.On 10 August 1904 the Imperial Russian Navy and the Imperial Japanese Navy had one of the longest-range gunnery duels to date—over 14,000 yd (13,000 m) during the Battle of the Yellow Sea. The Russian battleships were equipped with Liuzhol range finders with an effective range of 4,400 yd (4,000 m), and the Japanese ships had Barr & Stroud range finders that reached out to 6,600 yd (6,000 m), but both sides still managed to hit each other with 12-inch (305 mm) fire at 14,000 yd (13,000 m). Naval architects and strategists around the world took notice. | https://en.wikipedia.org/wiki/Dreadnought_battleship |
In naval gunnery, when long-range guns became available, an enemy ship would move some distance after the shells were fired. It became necessary to figure out where the enemy ship, the target, was going to be when the shells arrived. The process of keeping track of where the ship was likely to be was called rangekeeping, because the distance to the target—the range—was a very important factor in aiming the guns accurately. As time passed, train (also called bearing), the direction to the target, also became part of rangekeeping, but tradition kept the term alive. | https://en.wikipedia.org/wiki/Mathematical_discussion_of_rangekeeping |
Rangekeeping is an excellent example of the application of analog computing to a real-world mathematical modeling problem. Because nations had so much money invested in their capital ships, they were willing to invest enormous amounts of money in the development of rangekeeping hardware to ensure that the guns of these ships could put their projectiles on target. This article presents an overview of the rangekeeping as a mathematical modeling problem. | https://en.wikipedia.org/wiki/Mathematical_discussion_of_rangekeeping |
To make this discussion more concrete, the Ford Mk 1 Rangekeeper is used as the focus of this discussion. The Ford Mk 1 Rangekeeper was first deployed on the USS Texas in 1916 during World War I. This is a relatively well documented rangekeeper that had a long service life. While an early form of mechanical rangekeeper, it does illustrate all the basic principles. | https://en.wikipedia.org/wiki/Mathematical_discussion_of_rangekeeping |
The rangekeepers of other nations used similar algorithms for computing gun angles, but often differed dramatically in their operational use.In addition to long range gunnery, the launching of torpedoes also requires a rangekeeping-like function. The US Navy during World War II had the TDC, which was the only World War II-era submarine torpedo fire control system to incorporate a mechanical rangekeeper (other navies depended on manual methods). There were also rangekeeping devices for use with surface ship-launched torpedoes. For a view of rangekeeping outside that of the US Navy, there is a detailed reference that discusses the rangekeeping mathematics associated with torpedo fire control in the Imperial Japanese Navy. The following discussion is patterned after the presentations in World War II US Navy gunnery manuals. | https://en.wikipedia.org/wiki/Mathematical_discussion_of_rangekeeping |
In naval parlance, the sail (American usage) or fin (British/Commonwealth usage) (also known as a fairwater) of a submarine is the tower-like structure found on the dorsal (topside) surface of submarines. Submarine sails once housed the conning tower (command and communications data center), the periscope(s), radar and communications masts (antenna), though most of these functions have now been relocated to the hull proper (and so the sail is no longer considered a "conning tower"). When above the water's surface, the sail serves as an observation platform. | https://en.wikipedia.org/wiki/Submarine_sail |
It also provides an entrance and exit point on the submarine that has enough freeboard to prevent the submarine being swamped. Under water, the sail acts as a vertical stabilizer. In some submarines, the sail also supports diving planes (or fairwater planes), which are control surfaces used for underwater stability and steering. | https://en.wikipedia.org/wiki/Submarine_sail |
In naval terminology, a destroyer is a fast, maneuverable, long-endurance warship intended to escort larger vessels in a fleet, convoy, or battle group and defend them against powerful short-range attackers. They were originally developed in 1885 by Fernando Villaamil for the Spanish Navy as a defense against torpedo boats, and by the time of the Russo-Japanese War in 1904, these "torpedo boat destroyers" (TBDs) were "large, swift, and powerfully armed torpedo boats designed to destroy other torpedo boats". Although the term "destroyer" had been used interchangeably with "TBD" and "torpedo boat destroyer" by navies since 1892, the term "torpedo boat destroyer" had been generally shortened to simply "destroyer" by nearly all navies by the First World War.Before World War II, destroyers were light vessels with little endurance for unattended ocean operations; typically, a number of destroyers and a single destroyer tender operated together. After the war, destroyers grew in size. | https://en.wikipedia.org/wiki/Destroyer_minelayer |
The American Allen M. Sumner-class destroyers had a displacement of 2,200 tons, while the Arleigh Burke class has a displacement of up to 9,600 tons, a difference of nearly 340%. Moreover, the advent of guided missiles allowed destroyers to take on the surface-combatant roles previously filled by battleships and cruisers. This resulted in larger and more powerful guided-missile destroyers more capable of independent operation. | https://en.wikipedia.org/wiki/Destroyer_minelayer |
At the start of the 21st century, destroyers are the global standard for surface-combatant ships, with only two nations (the United States and Russia) officially operating the heavier cruisers, with no battleships or true battlecruisers remaining. Modern guided-missile destroyers are equivalent in tonnage but vastly superior in firepower to cruisers of the World War II era, and are capable of carrying nuclear-tipped cruise missiles. At 510 feet (160 m) long, a displacement of 9,200 tons, and with an armament of more than 90 missiles, guided-missile destroyers such as the Arleigh Burke class are actually larger and more heavily armed than most previous ships classified as guided-missile cruisers. The Chinese Type 055 destroyer has been described as a cruiser in some US Navy reports due to its size and armament.Some NATO navies, such as the Canadian, French, Spanish, Dutch, and German, use the term "frigate" for their destroyers, which leads to some confusion. | https://en.wikipedia.org/wiki/Destroyer_minelayer |
In naval terms, turret traditionally and specifically refers to a gun mounting where the entire mass rotates as one, and has a trunk that projects below the deck. The rotating part of a turret seen above deck is the gunhouse, which protects the mechanism and crew, and is where the guns are loaded. The gunhouse is supported on a bed of rotating rollers, and is not necessarily physically attached to the ship at the base of the rotating structure. In the case of the German battleship Bismarck, the turrets were not vertically restrained and fell out when she sank. | https://en.wikipedia.org/wiki/Gun_turret |
The British battlecruiser Hood, like some American battleships, did have vertical restraints.Below the gunhouse there may be a working chamber, where ammunition is handled, and the main trunk, which accommodates the shell and propellant hoists that bring ammunition up from the magazines below. There may be a combined hoist (cf the animated British turret) or separate hoists (cf the US turret cutaway). The working chamber and trunk rotate with the gunhouse, and sit inside a protective armoured barbette. | https://en.wikipedia.org/wiki/Gun_turret |
The barbette extends down to the main armoured deck (red in the animation). At the base of the turret sit handing rooms, where shell and propelling charges are passed from the shell room and magazine to the hoists. The handling equipment and hoists are complex arrangements of machinery that transport the shells and charges from the magazine into the base of the turret. | https://en.wikipedia.org/wiki/Gun_turret |
Bearing in mind that shells can weigh around a ton, the hoists have to be powerful and rapid; a 15-inch turret of the type in the animation was expected to perform a complete loading and firing cycle in a minute. The loading system is fitted with a series of mechanical interlocks that ensure that there is never an open path from the gunhouse to the magazine down which an explosive flash might pass. Flash-tight doors and scuttles open and close to allow the passage between areas of the turret. | https://en.wikipedia.org/wiki/Gun_turret |
Generally, with large-calibre guns, powered or assisted ramming is required to force the heavy shell and charge into the breech. As the hoist and breech must be aligned for ramming to occur, there is generally a restricted range of elevations at which the guns can be loaded; the guns return to the loading elevation, are loaded, then return to the target elevation, at which time they are said to be "in battery". | https://en.wikipedia.org/wiki/Gun_turret |
The animation illustrates a turret where the rammer is fixed to the cradle that carries the guns, allowing loading to occur across a wider range of elevations. Earlier turrets differed significantly in their operating principles. It was not until the last of the "rotating drum" designs described in the previous section were phased out that the "hooded barbette" arrangement above became the standard. | https://en.wikipedia.org/wiki/Gun_turret |
In naval tradition, mast is the traditional location of the non-judicial hearing under which a commanding officer studies and disposes of cases involving those in his command. In the United States Navy and United States Coast Guard, these proceedings take place under the authority of Article 15 of the Uniform Code of Military Justice (UCMJ). If the individual conducting the proceeding is either a captain, or a lower ranking officer (typically a commander or lieutenant commander) serving as commanding officer of a naval or coast guard vessel, an aviation squadron, or similar command afloat or ashore, then the proceeding is referred to as a captain's mast. | https://en.wikipedia.org/wiki/Non-judicial_punishment |
If an admiral is overseeing the mast, then the procedure is referred to as an admiral's mast or a flag mast.A captain's mast or admiral's mast is a procedure whereby the commanding officer must: Make inquiry into the facts surrounding minor offenses allegedly committed by a member of the command; Afford the accused a hearing as to such offenses; and Dispose of such charges by dismissing the charges, imposing punishment under the provisions of military law or referring the case to a court-martial.A captain's mast is not: A trial, as the term "non-judicial" implies; A conviction, even if punishment is imposed; An acquittal, even if punishment is not imposed.The term mast may also refer to when a captain or commanding officer makes him/herself available to hear concerns, complaints, or requests from the crew. Traditionally, on a naval vessel, the captain would stand at the main mast of that vessel when holding mast. The crew, who by custom did not speak with the captain, could speak to him directly at these times. It could also refer to the naval punishment of tying one to a mast and lashing them with a whip. In modern times, a meritorious mast refers to the commanding officer taking this time to single out a member of the crew for praise and present written recognition of work well done. | https://en.wikipedia.org/wiki/Non-judicial_punishment |
In naval warfare during the Age of Sail, a vessel always sought to use the wind to its advantage, maneuvering if possible to attack from windward. This was particularly important for less maneuverable square-rigged warships, which had limited ability to sail upwind, and sought to "hold the weather gage" entering battle.This was particularly important once artillery was introduced to naval warfare. Ships heel away from the wind, so the leeward vessel would expose more of her topsides to shot, in extreme cases even part of her bottom. | https://en.wikipedia.org/wiki/Lee_side |
In navigation the instrument is also called a cross-staff and was used to determine angles, for instance the angle between the horizon and Polaris or the sun to determine a vessel's latitude, or the angle between the top and bottom of an object to determine the distance to said object if its height is known, or the height of the object if its distance is known, or the horizontal angle between two visible locations to determine one's point on a map. The Jacob's staff, when used for astronomical observations, was also referred to as a radius astronomicus. With the demise of the cross-staff, in the modern era the name "Jacob's staff" is applied primarily to the device used to provide support for surveyor's instruments. | https://en.wikipedia.org/wiki/Jacob's_staff |
In navigation, a radio beacon or radiobeacon is a kind of beacon, a device that marks a fixed location and allows direction-finding equipment to find relative bearing. But instead of employing visible light, radio beacons transmit electromagnetic radiation in the radio wave band. They are used for direction-finding systems on ships, aircraft and vehicles.Radio beacons transmit a continuous or periodic radio signal with limited information (for example, its identification or location) on a specified radio frequency. Occasionally, the beacon's transmission includes other information, such as telemetric or meteorological data. Radio beacons have many applications, including air and sea navigation, propagation research, robotic mapping, radio-frequency identification (RFID), near-field communication (NFC) and indoor navigation, as with real-time locating systems (RTLS) like Syledis or simultaneous localization and mapping (SLAM). | https://en.wikipedia.org/wiki/Radio_beacon_station |
In navigation, a rhumb line (or loxodrome) is a line crossing all meridians of longitude at the same angle, i.e. a path derived from a defined initial bearing. That is, upon taking an initial bearing, one proceeds along the same bearing, without changing the direction as measured relative to true or magnetic north. | https://en.wikipedia.org/wiki/Navigation |
In navigation, a rhumb line or loxodrome is an arc crossing all meridians of longitude at the same angle. Loxodromes are the same as straight lines in the Mercator projection. A rhumb line is not a spherical spiral. Except for some simple cases, the formula of a rhumb line is complicated. | https://en.wikipedia.org/wiki/Curve_on_a_sphere |
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