A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring. Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass, many natural and synthetic dyes. Although heterocyclic chemical compounds may be inorganic compounds or organic compounds, most contain at least one carbon. While atoms that are neither carbon nor hydrogen are referred to in organic chemistry as heteroatoms, this is in comparison to the all-carbon backbone, but this does not prevent a compound such as borazine from being labelled "heterocyclic". IUPAC recommends the Hantzsch-Widman nomenclature for naming heterocyclic compounds. Heterocyclic compounds can be usefully classified based on their electronic structure; the saturated heterocycles behave like the acyclic derivatives. Thus and tetrahydrofuran are conventional amines and ethers, with modified steric profiles.
Therefore, the study of heterocyclic chemistry focuses on unsaturated derivatives, the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene and furan. Another large class of heterocycles are fused to benzene rings, which for pyridine, thiophene and furan are quinoline, benzothiophene and benzofuran, respectively. Fusion of two benzene rings gives rise to a third large family of compounds the acridine, dibenzothiophene and dibenzofuran; the unsaturated rings can be classified according to the participation of the heteroatom in the conjugated system, pi system. Heterocycles with three atoms in the ring are more reactive because of ring strain; those containing one heteroatom are, in general, stable. Those with two heteroatoms are more to occur as reactive intermediates. Common 3-membered heterocycles with one heteroatom are: Those with two heteroatoms include: Compounds with one heteroatom: Compounds with two heteroatoms: With heterocycles containing five atoms, the unsaturated compounds are more stable because of aromaticity.
The 5-membered ring compounds containing two heteroatoms, at least one of, nitrogen, are collectively called the azoles. Thiazoles and isothiazoles contain a nitrogen atom in the ring. Dithiolanes have two sulfur atoms. A large group of 5-membered ring compounds with three heteroatoms exists. One example is dithiazoles that contain a nitrogen atom. Six-membered rings with a single heteroatom: With two heteroatoms: With three heteroatoms: With four heteroatoms: With five heteroatoms: The hypothetical compound with six nitrogen heteroatoms would be hexazine. With 7-membered rings, the heteroatom must be able to provide an empty pi orbital for "normal" aromatic stabilization to be available. Compounds with one heteroatom include: Those with two heteroatoms include: Names in italics are retained by IUPAC and they do not follow the Hantzsch-Widman nomenclature Heterocyclic rings systems that are formally derived by fusion with other rings, either carbocyclic or heterocyclic, have a variety of common and systematic names.
For example, with the benzo-fused unsaturated nitrogen heterocycles, pyrrole provides indole or isoindole depending on the orientation. The pyridine analog is isoquinoline. For azepine, benzazepine is the preferred name; the compounds with two benzene rings fused to the central heterocycle are carbazole and dibenzoazepine. Thienothiophene are the fusion of two thiophene rings. Phosphaphenalenes are a tricyclic phosphorus-containing heterocyclic system derived from the carbocycle phenalene; the history of heterocyclic chemistry began in the 1800s, in step with the development of organic chemistry. Some noteworthy developments: 1818: Brugnatelli isolates alloxan from uric acid 1832: Dobereiner produces furfural by treating starch with sulfuric acid 1834: Runge obtains pyrrole by dry distillation of bones 1906: Friedlander synthesizes indigo dye, allowing synthetic chemistry to displace a large agricultural industry 1936: Treibs isolates chlorophyl derivatives from crude oil, explaining the biological origin of petroleum.
1951: Chargaff's rules are described, highlighting the role of heterocyclic compounds in the genetic code. Heterocyclic compounds are pervasive in many areas of technology. Many drugs are heterocyclic compounds. Hantzsch-Widman nomenclature, IUPAC Heterocyclic amines in cooked meat, US CDC List of known and probable carcinogens, American Cancer Society List of known carcinogens by the State of California, Proposition 65
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head close to the sensory organs for senses such as vision; the brain is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains 14–16 billion neurons, the estimated number of neurons in the cerebellum is 55–70 billion; each neuron is connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells. Physiologically, the function of the brain is to exert centralized control over the other organs of the body; the brain acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows coordinated responses to changes in the environment.
Some basic types of responsiveness such as reflexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires the information integrating capabilities of a centralized brain. The operations of individual brain cells are now understood in considerable detail but the way they cooperate in ensembles of millions is yet to be solved. Recent models in modern neuroscience treat the brain as a biological computer different in mechanism from an electronic computer, but similar in the sense that it acquires information from the surrounding world, stores it, processes it in a variety of ways; this article compares the properties of brains across the entire range of animal species, with the greatest attention to vertebrates. It deals with the human brain insofar; the ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because much more can be said about them in a human context.
The most important is brain disease and the effects of brain damage, that are covered in the human brain article. The shape and size of the brain varies between species, identifying common features is difficult. There are a number of principles of brain architecture that apply across a wide range of species; some aspects of brain structure are common to the entire range of animal species. The simplest way to gain information about brain anatomy is by visual inspection, but many more sophisticated techniques have been developed. Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, sliced apart for examination of the interior. Visually, the interior of the brain consists of areas of so-called grey matter, with a dark color, separated by areas of white matter, with a lighter color. Further information can be gained by staining slices of brain tissue with a variety of chemicals that bring out areas where specific types of molecules are present in high concentrations.
It is possible to examine the microstructure of brain tissue using a microscope, to trace the pattern of connections from one brain area to another. The brains of all species are composed of two broad classes of cells: neurons and glial cells. Glial cells come in several types, perform a number of critical functions, including structural support, metabolic support and guidance of development. Neurons, are considered the most important cells in the brain; the property that makes neurons unique is their ability to send signals to specific target cells over long distances. They send these signals by means of an axon, a thin protoplasmic fiber that extends from the cell body and projects with numerous branches, to other areas, sometimes nearby, sometimes in distant parts of the brain or body; the length of an axon can be extraordinary: for example, if a pyramidal cell of the cerebral cortex were magnified so that its cell body became the size of a human body, its axon magnified, would become a cable a few centimeters in diameter, extending more than a kilometer.
These axons transmit signals in the form of electrochemical pulses called action potentials, which last less than a thousandth of a second and travel along the axon at speeds of 1–100 meters per second. Some neurons emit action potentials at rates of 10–100 per second in irregular patterns. Axons transmit signals to other neurons by means of specialized junctions called synapses. A single axon may make as many as several thousand synaptic connections with other cells; when an action potential, traveling along an axon, arrives at a synapse, it causes a chemical called a neurotransmitter to be released. The neurotransmitter binds to receptor molecules in the membrane of the target cell. Synapses are the key functional elements of the brain; the essential function of the brain is cell-to-cell communication, synapses are the points at which communication occurs. The human brain has been estimated to contain 100 trillion synapses; the functions of these synapses are diverse: some are excitatory.
Crataegus monogyna, known as common hawthorn, oneseed hawthorn, or single-seeded hawthorn, is a species of hawthorn native to Europe, northwest Africa and western Asia. It has been introduced in many other parts of the world, it can be an invasive weed. Other common names include may, maythorn, whitethorn and haw; this species is one of several that have been referred to as Crataegus oxyacantha, a name, rejected by the botanical community as too ambiguous. In 1793 Medikus published the name C. apiifolia for a European hawthorn now included in C. monogyna, but that name is illegitimate under the rules of botanical nomenclature. The common hawthorn is a small tree 5 -- 14 metres tall, with a dense crown; the bark is dull brown with vertical orange cracks. The younger stems bear sharp thorns 12. 5mm long. The leaves are 20 to 40 mm long and lobed, sometimes to the midrib, with the lobes spreading at a wide angle; the upper surface is dark green paler underneath. The hermaphrodite flowers are produced in late spring in corymbs of 5–25 together.
The flowers are pollinated by midges and other insects and in the year bear numerous haws. The haw is a small, oval dark red fruit about 10 mm long, berry-like, but structurally a pome containing a single seed. Haws are important for wildlife in winter thrushes and waxwings; the common hawthorn is distinguished from the related but less widespread Midland hawthorn by its more upright growth, the leaves being lobed, with spreading lobes, in the flowers having just one style, not two or three. However they are inter-fertile and hybrids occur frequently. Crataegus monogyna is one of the most common species used as the "hawthorn" of traditional herbalism; the plant parts used are sprigs with both leaves and flowers, or alternatively the fruit. Hawthorne has been investigated by evidence-based medicine for treating cardiac insufficiency. Crataegus monogyna is a source of antioxidant phytochemicals extracts of hawthorn leaves with flowers. Common hawthorn is extensively planted as a hedge plant for agricultural use.
Its spines and close branching habit render it stock- and human-proof, with some basic maintenance. The traditional practice of hedge laying is most practised with this species, it is a good fire wood which burns with little smoke. Numerous hybrids exist, some of; the most used hybrid is C. × media, of which several cultivars are known, including the popular'Paul's Scarlet' with dark pink double flowers. Other garden shrubs that have sometimes been suggested as possible hybrids involving the common hawthorn, include the various-leaved hawthorn of the Caucasus, only occasionally found in parks and gardens; the fruit of hawthorn, called haws, are edible raw but are made into jellies and syrups, used to make wine, or to add flavour to brandy. Botanically they are pomes. A haw is small and oblong, similar in size and shape to a small olive or grape, red when ripe. Haws develop in groups of three along smaller branches, they are delicate in taste. In this species they have only one seed, but in other species of hawthorn there may be up to five seeds.
Petals are edible, as are the leaves, which if picked in spring when still young are tender enough to be used in salads. Hawthorn petals are used in the medieval English recipe for spinee, an almond-milk based pottage recorded in'The Forme of Cury' by the Chief Master-Cook of King Richard II, c. 1390. An ancient specimen, reputedly the oldest tree of any species in France, is to be found alongside the church at Saint Mars sur la Futaie, Mayenne; the tree has a height of 9 m, a girth of 265 cm. The inscription on the plaque beneath reads: "This hawthorn is the oldest tree in France, its origin goes back to St Julien". A famous specimen in England was the Glastonbury or Holy Thorn which, according to legend, sprouted from the staff of Joseph of Arimathea after he thrust it into the ground while visiting Glastonbury in the 1st century AD; the tree was noteworthy because it flowered twice in a year, once in the late spring, normal, but once after the harshness of midwinter had passed. The original tree at Glastonbury Abbey, felled in the 1640s during the English Civil War, has been propagated as the cultivar'Biflora'.
A replacement was planted by the local council in 1951, but was cut down by vandals in 2010. The oldest known living specimen in East Anglia, in the United Kingdom, is known as The Hethel Old Thorn, is located in the churchyard in the small village of Hethel, south of Norwich, in Norfolk, it is reputed to be more than 700 years old. The hawthorn is associated with Faerie in Ireland, as such is not disturbed by those who believe in the danger fairies traditionally represent; the hawthorn button-top gall on Hawthorn, is caused by the dipteron gall-midge Dasineura crataegi. Haweater List of Lepidoptera that feed on hawthorns Folklore about hawthorns the European species C. laevigata and/or C. monogyna and hybrids between these two species. Philips, R.. Trees
Cauliflower is one of several vegetables in the species Brassica oleracea in the genus Brassica, in the family Brassicaceae. It is an annual plant that reproduces by seed. Only the head is eaten – the edible white flesh sometimes called "curd"; the cauliflower head is composed of a white inflorescence meristem. Cauliflower heads resemble those in broccoli, which differs in having flower buds as the edible portion. Brassica oleracea includes broccoli, brussels sprouts, collard greens, kale, collectively called "cole" crops, though they are of different cultivar groups. In the 1st century AD, Pliny included what he called cyma among his descriptions of cultivated plants in Natural History: "Ex omnibus brassicae generibus suavissima est cyma,". Pliny's descriptions refer to the flowering heads of an earlier cultivated variety of Brassica oleracea, but comes close to describing modern cauliflower. In the Middle Ages early forms of cauliflower were associated with the island of Cyprus, with the Arab botanists Ibn al-'Awwam and Ibn al-Baitar, in the 12th and 13th centuries claiming its origins were Cyprus.
This association continued into Western Europe, where cauliflowers were sometimes known as Cyprus colewart, there was extensive trade in western Europe in cauliflower seeds from Cyprus, under the French Lusignan rulers of the island, until well into the sixteenth century. François Pierre La Varenne employed chouxfleurs in Le cuisinier françois, they were introduced to France from Genoa in the 16th century, are featured in Olivier de Serres' Théâtre de l'agriculture, as cauli-fiori "as the Italians call it, which are still rather rare in France. It was introduced to India in 1822 from England by the British; the word "cauliflower" derives from the Italian cavolfiore, meaning "cabbage flower". The ultimate origin of the name is from the Latin words caulis and flōs. Cauliflower is difficult to grow compared to cabbage, with common problems such as an underdeveloped head and poor curd quality; as weather is a limiting factor for producing cauliflower, the plant grows best in cool daytime temperatures 70–85 °F, with plentiful sun, moist soil conditions high in organic matter and sandy soils.
The earliest maturity possible for cauliflower is 7 to 12 weeks from transplanting. In the northern hemisphere, fall season plantings in July may enable harvesting before autumn frost. Long periods of sun exposure in hot summer weather may cause cauliflower heads to discolor with a red-purple hue. Transplantable cauliflowers can be produced in containers as flats, hotbeds, or in the field. In soil, loose, well-drained and fertile, field seedlings are shallow-planted 0.5 inches and thinned by ample space (about 12 plants per 1 foot. Ideal growing temperatures are about 65 °F when seedlings are 25 to 35 days old. Applications of fertilizer to developing seedlings begin when leaves appear with a starter solution weekly. Transplanting to the field begins late spring and may continue until mid-summer. Row spacing is about 15–18 inches. Rapid vegetative growth after transplanting may benefit from such procedures as avoiding spring frosts, using starter solutions high in phosphorus, irrigating weekly, applying fertilizer.
The most important disorders affecting cauliflower quality are a hollow stem, stunted head growth or buttoning, ricing and leaf-tip burn. Among major pests affecting cauliflower are aphids, root maggots, cutworms and flea beetles; the plant is susceptible to black rot, black leg, club root, black leaf spot, downy mildew. When cauliflower is mature, heads appear as clear white, 6–8 inches in diameter, should be cooled shortly after harvest. Forced air cooling to remove heat from the field during hot weather may be needed for optimal preservation. Short-term storage is possible using cool, high-humidity storage conditions. There are four major groups of cauliflower. Italian This specimen is diverse in appearance and annual in type; this group includes white, various brown, green and yellow cultivars. This type is the ancestral form from which the others were derived. Northern European annuals Used in Europe and North America for summer and fall harvest, it was developed in Germany in the 18th century, includes the old cultivars Erfurt and Snowball.
Northwest European biennial Used in Europe for winter and early spring harvest, this was developed in France in the 19th century, includes the old cultivars Angers and Roscoff. Asian A tropical cauliflower used in China and India, it was developed in India during the 19th century from the now-abandoned Cornish type, includes old varieties Early Benaras and Early Patna. There are hundreds of historic and current commercial varieties used around the world. A comprehensive list of about 80 North American varieties is maintained at North Carolina State University. White White cauliflower is the most common color of cauliflower having a contrasting white head surrounded by green leaves. Orange Orange cauliflower contains beta-carotene as the orange pigment, a provitamin A compound; this orange trait originated from a natural mutant found in a cauliflower field in Canada. Cultivars include'Cheddar' and'Orange Bouquet'. Green Green cauliflower, of the B. oleracea botrytis group, is sometimes called broccoflower.
It is available in the normal curd shape and with a fractal spiral curd cal
European Chemicals Agency
The European Chemicals Agency is an agency of the European Union which manages the technical and administrative aspects of the implementation of the European Union regulation called Registration, Evaluation and Restriction of Chemicals. ECHA is the driving force among regulatory authorities in implementing the EU's chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and addresses chemicals of concern, it is located in Finland. The agency headed by Executive Director Bjorn Hansen, started working on 1 June 2007; the REACH Regulation requires companies to provide information on the hazards and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most used substances have been registered; the information is technical but gives detail on the impact of each chemical on people and the environment.
This gives European consumers the right to ask retailers whether the goods they buy contain dangerous substances. The Classification and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU; this worldwide system makes it easier for workers and consumers to know the effects of chemicals and how to use products safely because the labels on products are now the same throughout the world. Companies need to notify ECHA of the labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100 000 substances; the information is available on their website. Consumers can check chemicals in the products. Biocidal products include, for example, insect disinfectants used in hospitals; the Biocidal Products Regulation ensures that there is enough information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation; the law on Prior Informed Consent sets guidelines for the import of hazardous chemicals.
Through this mechanism, countries due to receive hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have serious effects on human health and the environment are identified as Substances of Very High Concern 1; these are substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment and do not break down. Other substances considered. Companies manufacturing or importing articles containing these substances in a concentration above 0,1% weight of the article, have legal obligations, they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy. Once a substance has been identified in the EU as being of high concern, it will be added to a list; this list is available on ECHA's website and shows consumers and industry which chemicals are identified as SVHCs.
Substances placed on the Candidate List can move to another list. This means that, after a given date, companies will not be allowed to place the substance on the market or to use it, unless they have been given prior authorisation to do so by ECHA. One of the main aims of this listing process is to phase out SVHCs where possible. In its 2018 substance evaluation progress report, ECHA said chemical companies failed to provide “important safety information” in nearly three quarters of cases checked that year. "The numbers show a similar picture to previous years" the report said. The agency noted that member states need to develop risk management measures to control unsafe commercial use of chemicals in 71% of the substances checked. Executive Director Bjorn Hansen called non-compliance with REACH a "worry". Industry group CEFIC acknowledged the problem; the European Environmental Bureau called for faster enforcement to minimise chemical exposure. European Chemicals Bureau Official website
Scallop is a common name, applied to any one of numerous species of saltwater clams or marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is sometimes applied to species in other related families within the superfamily Pectinoidea, which includes the thorny oysters. Scallops are a cosmopolitan family of bivalves which are found in all of the world's oceans, although never in fresh water, they are one of few groups of bivalves to be "free-living", with many species capable of swimming short distances and of migrating some distance across the ocean floor. A small minority of scallop species live cemented to rocky substrates as adults, while others attach themselves to stationary or rooted objects such as sea grass at some point in their lives by means of a filament they secrete called a byssal thread; the majority of species, live recumbent on sandy substrates, when they sense the presence of a predator such as a starfish, they may attempt to escape by swimming swiftly but erratically through the water using jet propulsion created by clapping their shells together.
Scallops have a well-developed nervous system, unlike most other bivalves all scallops have a ring of numerous simple eyes situated around the edge of their mantles. Many species of scallops are prized as a food source, some are farmed as aquaculture; the word "scallop" is applied to the meat of these bivalves, the adductor muscle, sold as seafood. The brightly coloured, fan-shaped shells of scallops with their radiating and fluted ornamentation are valued by shell collectors, have been used since ancient times as motifs in art and design. Owing to their widespread distribution, scallop shells are a common sight on beaches and are brightly coloured, making them a popular object to collect among beachcombers and vacationers; the shells have a significant place in popular culture, including symbolism. Scallops inhabit all the oceans of the world, with the largest number of species living in the Indo-Pacific region. Most species live in shallow waters from the low tide line to 100 m, while others prefer much deeper water.
Although some species only live in narrow environments, most are opportunistic and can live under a wide variety of conditions. Scallops can be found living within, upon, or under either rocks, rubble, sea grass, sand, or mud. Most scallops begin their lives as byssally attached juveniles, an ability that some retain throughout their lives while others grow into freeliving adults. Little variation occurs in the internal arrangement of organs and systems within the scallop family, what follows can be taken to apply to the anatomy of any given scallop species; the shell of a scallop consists of two sides or valves, a left valve and a right one, divided by a plane of symmetry. Most species of scallops rest on their right valve, this valve is deeper and more rounded than the left valve, which in many species is concave. With the hinge of the two valves oriented towards the top, one side corresponds to the animal's morphological anterior or front, the other is the posterior or rear, the hinge is the dorsal or back/ top region, the bottom corresponds to the ventral or underside/ belly.
However, as many scallop shells are more or less bilaterally symmetrical, as well as symmetrical front/back, determining which way a given animal is "facing" requires detailed information about its valves. The model scallop shell consists of two shaped valves with a straight hinge line along the top, devoid of teeth, producing a pair of flat wings or "ears" on either side of its midpoint, a feature, unique to and apparent in all adult scallops; these ears may be of similar size and shape. As is the case in all bivalves, a series of lines and/or growth rings originates at the center of the hinge, at a spot called the "beak" surrounded by a raised area called the "umbo"; these growth rings increase in size downwards. The shells of most scallops are streamlined to facilitate ease of movement during swimming at some point in their lifecycles, while providing protection from predators. Scallops with ridged valves have the advantage of the architectural strength provided by these ridges called "ribs", although the ribs are somewhat costly in terms of weight and mass.
A unique feature of the scallop family is the presence, at some point during the animal's lifecycle, of a distinctive and taxonomically important shell feature, a comb-like structure called a ctenolium located on the anterior edge of the right valve next to the valve's byssal notch. Though many scallops lose this feature as they become free-swimming adults, all scallops have a ctenolium at some point during their lives, no other bivalve has an analogous shell feature; the ctenolium is found in modern scallops only. Like the true oysters, scallops have a single central adductor muscle, thus the inside of their shells has a characteristic central scar, marking the point of attachment for this muscle; the adductor muscle of scallops is larger and more developed than those of oysters, because scallops are active swimmers.
Beef is the culinary name for meat from cattle skeletal muscle. Humans have been eating beef since prehistoric times. Beef is a source of high-quality protein and nutrients. Beef skeletal muscle meat can be used as is by cutting into certain parts roasts, short ribs or steak, while other cuts are processed. Trimmings, on the other hand, are mixed with meat from older, leaner cattle, are ground, minced or used in sausages; the blood is used in some varieties called blood sausage. Other parts that are eaten include other muscles and offal, such as the oxtail, tongue, tripe from the reticulum or rumen, the heart, the brain, the kidneys, the tender testicles of the bull; some intestines are cooked and eaten as is, but are more cleaned and used as natural sausage casings. The bones are used for making beef stock. Beef from steers and heifers is similar. Depending on economics, the number of heifers kept for breeding varies; the meat from older bulls, because it is tougher, is used for mince. Cattle raised for beef may be allowed to roam free on grasslands, or may be confined at some stage in pens as part of a large feeding operation called a feedlot, where they are fed a ration of grain, roughage and a vitamin/mineral preblend.
Beef is the third most consumed meat in the world, accounting for about 25% of meat production worldwide, after pork and poultry at 38% and 30% respectively. In absolute numbers, the United States and the People's Republic of China are the world's three largest consumers of beef. According to the data from OECD, the average Uruguayan ate over 42 kg of beef or veal in 2014, representing the highest beef/veal consumption per capita in the world. In comparison, the average American consumed only about 24 kg beef or veal in the same year, while African countries, such as Mozambique and Nigeria, consumed the least beef or veal per capita. In 2015, the world's largest exporters of beef were India and Australia. Beef production is important to the economies of Uruguay, Paraguay, Argentina and Nicaragua; the word beef is from the Latin bōs, in contrast to cow, from Middle English cou. After the Norman Conquest, the French-speaking nobles who ruled England used French words to refer to the meats they were served.
Thus, various Anglo-Saxon words were used for the animal by the peasants, but the meat was called boef by the French nobles — who did not deal with the live animal — when it was served to them. This is one example of the common English dichotomy between the words for animals and their meat, found in such English word-pairs as pig/pork, deer/venison, sheep/mutton and chicken/poultry. Beef is cognate with bovine through the Late Latin bovīnus. People have eaten the flesh of bovines from prehistoric times. People domesticated cattle around 8000 BC to provide ready access to beef and leather. Most cattle originated in the Old World, with the exception of bison hybrids, which originated in the Americas. Examples include the Wagyū from Japan, Ankole-Watusi from Egypt, longhorn Zebu from the Indian subcontinent, it is unknown when people started cooking beef. Cattle were used across the Old World as draft animals, for milk, or for human consumption. With the mechanization of farming, some breeds were bred to increase meat yield, resulting in Chianina and Charolais cattle, or to improve the texture of meat, giving rise to the Murray Grey and Wagyū.
Some breeds have been selected for both milk production, such as the Brown Swiss. In the United States, the growth of the beef business was due to expansion in the Southwest. Upon the acquisition of grasslands through the Mexican–American War of 1848, the expulsion of the Plains Indians from this region and the Midwest, the American livestock industry began, starting with the taming of wild longhorn cattle. Chicago and New York City were the first to benefit from these developments in their stockyards and in their meat markets. Beef cattle are raised and fed using a variety of methods, including feedlots, free range, ranching and Intensive animal farming. Beef is first divided into primal cuts, pieces of meat butchering; these are basic sections from which other subdivisions are cut. The term "primal cut" is quite different from "prime cut", used to characterize cuts considered to be of higher quality. Since the animal's legs and neck muscles do the most work, they are the toughest. Different countries and cuisines have different cuts and names, sometimes use the same name for a different cut.