ratio of word probabilities predicted from brain for bed and bee

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bed

bee

top 10 words in brain distribution (in article):
sexual people woman build house world time refer form century
top 10 words in brain distribution (in article):
species plant fruit food seed produce flower male human female
top 10 words in brain distribution (not in article):
city love god animal species state human female store male
top 10 words in brain distribution (not in article):
animal grow tree leaf breed sugar hunt cat dog water
times more probable under bed 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under bee
(words not in the model)
A bed'" is a piece of furniture (or a location) used as a place to sleep, and as a primary place for relaxation and sexual intercourse. To make beds more comfortable, mattresses are usually placed on top of them. The second layer is the box spring Inner-sprung Base. The box spring or "divan" is a large mattress-sized box containing wood and springs that provide additional support and suspension for the mattress. The box spring will typically lie on a bed frame(which lifts the mattress mattress-box spring off the ground) or on slats (usually made of 2" x 4" wood). A "headboard", "side rails", and "footboard" or "front rail" will complete the bed. "Headboard only" beds often incorporate a "dust ruffle", "bed skirt", or "valance sheet" to hide the bed frame. For greater head support, most people use a pillow, placed at the top of a mattress. Also used is some form of covering blanket to insulate the sleeper, often bed sheets, a quilt, or a duvet. Also, some people prefer to dispense with the box spring and bed frame, and replace it with a platform bed style. This is more common in Europe and Japan. The Ancient World. Early beds were little more than piles of straw or some other natural materials. An important change was raising them off the ground, to avoid draughts, dirt, and pests. The Egyptians had high bedsteads which were ascended by steps, with bolsters or pillows, and curtains to hang round. The elite of Egyptian society such as its pharaohs and queens even had beds made of wood and gilded with gold. Often there was a head-rest as well, semi-cylindrical and made of stone, wood or metal. Assyrians, Medes and Persians had beds of a similar kind, and frequently decorated their furniture with inlays or appliqués of metal, mother-of-pearl and ivory. The oldest account of a bed is probably that of Odysseus: a charpoy woven of rope, plays a role in the Odyssey. A similar bed can be seen at the St Fagans National History Museum in Wales. Odysseus also gives an account of how he crafted the nuptial bed for himself and Penelope, out of an ancient, huge olive tree trunk that used to grow on the spot before the bridal chamber was built. His detailed description finally persuades the doubting Penelope that the shipwrecked, aged man is indeed her long-lost husband. Homer also mentions the inlaying of the woodwork of beds with gold, silver and ivory.The Greek bed had a wooden frame, with a board at the head and bands of hide laced across, upon which skins were placed. At a later period the bedstead was often veneered with expensive woods; sometimes it was of solid ivory veneered with tortoise-shell and with silver feet; often it was of bronze. The pillows and coverings also became more costly and beautiful; the most celebrated places for their manufacture were Miletus, Corinth and Carthage. Folding beds, too, appear in the vase paintings. The Roman mattresses were stuffed with reeds, hay, wool or feathers; the last was used towards the end of the Republic, when custom demanded luxury. Small cushions were placed at the head and sometimes at the back. The bedsteads were high and could only be ascended by the help of steps. They were often arranged for two persons, and had a board or railing at the back as well as the raised portion at the head. The counterpanes were sometimes very costly, generally purple embroidered with figures in gold; and rich hangings fell to the ground masking the front. The bedsteads themselves were often of bronze inlaid with silver, and Elagabalus had one of solid silver. In the walls of some of the houses at Pompeii bed niches are found which were probably closed by curtains or sliding partitions. Ancient Romans had various kinds of beds for repose. These included: Medieval Europe. The ancient Germans lay on the floor on beds of leaves covered with skins, or in a kind of shallow chest filled with leaves and moss. In the early middle ages they laid carpets on the floor or on a bench against the wall, placed upon them mattresses stuffed with feathers, wool or hair, and used skins as a covering. They appear to have generally lain naked in bed, wrapping themselves in the large linen sheets which were stretched over the cushions. In the 13th century luxury increased, and bedsteads were made of wood much decorated with inlaid, carved and painted ornament. They also used folding beds, which served as couches by day and had cushions covered with silk laid upon leather. At night a linen sheet was spread and pillows placed, while silk-covered skins served as coverlets. Curtains were hung from the ceiling or from an iron arm projecting from the wall. The Carolingian manuscripts show metal bedsteads much higher at the head than at the feet, and this shape continued in use until the 13th century in France, many cushions being added to raise the body to a sloping position. In the 12th-century manuscripts the bedsteads appear much richer, with inlays, carving and painting, and with embroidered coverlets and mattresses in harmony. Curtains were hung above the bed, and a small hanging lamp is often shown. In the 14th century the woodwork became of less importance, being generally entirely covered by hangings of rich materials. Silk, velvet and even cloth of gold were much used. Inventories from the beginning of the 14th century give details of these hangings lined with fur and richly embroidered. Then it was that the tester bed made its first appearance, the tester being slung from the ceiling or fastened to the walls, a form which developed later into a room within a room, shut in by double curtains, sometimes even so as to exclude all drafts. The space between bed and wall was called the "ruelle", and very intimate friends were received there. In the 15th century beds became very large, reaching to 7 or 8 feet by 6 or 7 feet. The mattresses were often filled with pea-shucks, straw or feathers. At this time great personages were in the habit of carrying most of their property about with them, including beds and bed-hangings, and for this reason the bedsteads were for the most part mere frameworks to be covered up; but about the beginning of the 16th century bedsteads were made lighter and more decorative, since the lords remained in the same place for longer periods. Renaissance and Modern Europe. In the 17th century, which has been called "the century of magnificent beds," the style "a la duchesse", with tester and curtains only at the head, replaced the more enclosed beds in France, though they lasted much longer in England. Louis XIV had an enormous number of sumptuous beds, as many as 413 being described in the inventories of his palaces. Some of them had embroideries enriched with pearls, and figures on a silver or golden ground. The great bed at Versailles had crimson velvet curtains on which "The Triumph of Venus" was embroidered. So much gold was used that the velvet scarcely showed. In the 18th century feather pillows were first used as coverings in Germany, which in the fashions of the bed and the curious etiquette connected with the bedchamber followed France for the most part. The beds were "a la duchesse", but in France itself there was great variety both of name and shape. The custom of the "bed of justice" upon which the king of France reclined when he was present in parliament, the princes being seated, the great officials standing, and the lesser officials kneeling, was held to denote the royal power even more than the throne. Louis XI is credited with its first use, and the custom lasted till the end of the monarchy. In the "chambre de parade", where the ceremonial bed was placed, certain persons, such as ambassadors or great lords, whom it was desired to honour, were received in a more intimate fashion than the crowd of courtiers. At Versailles women received their friends in their beds, both before and after childbirth, during periods of mourning, and even directly after marriage; in fact in any circumstances which were thought deserving of congratulation or condolence. During the 17th century this curious custom became general, perhaps to avoid the tiresome details of etiquette. Portable beds were used in high society in France till the end of the "ancien regime". The earliest of which mention has been found belonged to Charles the Bold. They had curtains over a light framework, and were in their way as fine as the stationary beds. Iron beds appear in the 18th century; the advertisements recommend them as free from the insects which sometimes infested wooden bedsteads. Elsewhere, there was also the closed bed with sliding or folding shutters, and in England, where beds were commonly quite simple in form, the four poster was the usual citizen's bed until the middle of the 19th century. Bed sizes. Beds come in a wide array of shapes and sizes. Most countries have a standard set of four sizes of mattresses. While the "Double" size appears to be standard among English speaking countries, based on the imperial measurement of 4 ft 6 in by 6 ft 3 in, the sizes for other bed types tend to vary. The European sizes differ; they are based on the metric system. A king-sized bed differs from the other sizes in implementation, as it is not common to have a king-sized box spring; rather, two smaller box-springs are used under a king-sized mattress. It is a common misconception that on a U.S. "Standard" or "Eastern King", the box springs are identical in size to a "Twin Extra-Long," however "Twin Extra-Long" mattresses next to each other add up to 78 inches wide instead of the 76 inch width that is standard for an "Eastern King." Standard sizes. Modern manufacturing conventions have resulted in a limited number of standard sizes of commercial bedding for mattresses and box springs. They vary by country of origin. The sizes in the UK and Ireland, other than the "Double", vary compared to the U.S. sizes, being generally smaller. The U.S. "Queen" corresponds to UK "King" and "King" to "Super King". The European or continental basic sizes are similar to the UK but have a set length of 2 metres. The denominations Queen, King and Super King are not used in continental Europe, and "Double" refers to 140cm or any higher width. Instead of these US UK denominations, the bed width is given in centimetres. These dimensions are for the mattress—the actual bed frame will be a little bigger in order to fully encompass and support the mattress. The thickness of the mattress may vary considerably. Other European sizes. Modern continental Europe practice is to refer to a bed by explicit width or size ("80 cm bed" or "80x200 cm bed"). Other sizes found include: In France, Spain and Mexico, the length of older beds is sometimes 1.9 metres instead of 2 metres. Most mattress sizes in the Netherlands are also available in extra long, meaning 2.2 m instead of 2.0 m. In the Scandinavian countries, standards vary from one country to another. In Norway, these sizes are used: Small single: 0.75 x 2m (30 x 79 inches) Single: 0.90 x 2m (35.5 x 79 inches) Large Single: 1.2m x 2m (47 x 79 inches) Queen: 1.50 x 2m (60 x 79 inches, equal to two small single mattresses) King: 1.80 x 2m (71 x 79 inches, equal to two single mattresses) Beds mattresses are often available also in "extra long" (2.2m or 86.6 inches length). Some older beds are only 1.9m (75 inches) long, while antique beds often are even shorter (since they in older times often slept in a reclined position rather than the close to supine position which is common today). Other New Zealand sizes. The following bed sizes are available in New Zealand: Types of beds. There are many varieties of beds: Bed frames. Bed frames, also called bed steads, are made of wood or metal. The frame is made up of head, foot, and side rails. For heavy duty or larger frames (such as for queen- and king-sized beds), the bed frame also includes a center support rail. These rails are assembled to create a box for the mattress or mattress box spring to sit on. Though not truly parts of a bed frame, many people include headboards, footboards, and bed rails in their definition of bed frames. Headboards and footboards can be wood or metal. They can be stained, painted, or covered in fabric or leather. Bed rails are made of wood or metal and are attached to a headboard and footboard. Wooden slats are placed perpendicular to the bed rails to support the mattress mattress box spring. Bed rails and frames are often attached to the bed post using knock-down fittings. A knock-down fitting enables the bed to be easily dismantled for removal. Primary knock-down fittings for bed rails are as follows: Safety rails can be added to the sides of a bed (normally a children's bed) to stop anyone falling out of the sides of the bed. A safety rail is normally a piece of wood that attaches to the side rails on one or both sides of the bed. They are made so that they can be easily removed when no longer required. Bees'" are flying insects closely related to wasps and ants. Bees are a monophyletic lineage within the superfamily "'Apoidea'", presently classified by the unranked taxon name "'Anthophila'". There are nearly 20,000 known species of bee, in nine recognized families, though many are undescribed and the actual number is probably higher. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. Introduction. Bees are adapted for feeding on nectar and pollen, the former primarily as an energy source, and the latter primarily for protein and other nutrients. Most pollen is used as food for larvae. Bees have a long proboscis (a complex "tongue") that enables them to obtain the nectar from flowers. They have antennae almost universally made up of 13 segments in males and 12 in females, as is typical for the superfamily. Bees all have two pairs of wings, the hind pair being the smaller of the two; in a very few species, one sex or caste has relatively short wings that make flight difficult or impossible, but none is wingless. The smallest bee is "Trigona minima", a stingless bee whose workers are about 2.1 mm (5 64") long. The largest bee in the world is "Megachile pluto", a leafcutter bee whose females can attain a length of 39 mm (1.5"). Members of the family Halictidae, or sweat bees, are the most common type of bee in the Northern Hemisphere, though they are small and often mistaken for wasps or flies. The best-known bee species is the European honey bee, which, as its name suggests, produces honey, as do a few other types of bee. Human management of this species is known as beekeeping or apiculture. Bees are the favorite meal of "Merops apiaster", the bee-eater bird. Other common predators are kingbirds, mockingbirds, bee wolves, and dragonflies. Pollination. Bees play an important role in pollinating flowering plants, and are the major type of pollinator in ecosystems that contain flowering plants. Bees either focus on gathering nectar or on gathering pollen depending on demand, especially in social species. Bees gathering nectar may accomplish pollination, but bees that are deliberately gathering pollen are more efficient pollinators. It is estimated that one third of the human food supply depends on insect pollination, most of which is accomplished by bees, especially the domesticated European honey bee. Contract pollination has overtaken the role of honey production for beekeepers in many countries. Monoculture and the massive decline of many bee species (both wild and domesticated) have increasingly caused honey bee keepers to become migratory so that bees can be concentrated in seasonally-varying high-demand areas of pollination. Most bees are fuzzy and carry an electrostatic charge, which aids in the adherence of pollen. Female bees periodically stop foraging and groom themselves to pack the pollen into the scopa, which is on the legs in most bees, and on the ventral abdomen on others, and modified into specialized pollen baskets on the legs of honey bees and their relatives. Many bees are opportunistic foragers, and will gather pollen from a variety of plants, while others are oligolectic, gathering pollen from only one or a few types of plant. A small number of plants produce nutritious floral oils rather than pollen, which are gathered and used by oligolectic bees. One small subgroup of stingless bees, called "vulture bees," is specialized to feed on carrion, and these are the only bees that do not use plant products as food. Pollen and nectar are usually combined together to form a "provision mass", which is often soupy, but can be firm. It is formed into various shapes (typically spheroid), and stored in a small chamber (a "cell"), with the egg deposited on the mass. The cell is typically sealed after the egg is laid, and the adult and larva never interact directly (a system called "mass provisioning"). Visiting flowers can be a dangerous occupation. Many assassin bugs and crab spiders hide in flowers to capture unwary bees. Other bees are lost to birds in flight. Insecticides used on blooming plants kill many bees, both by direct poisoning and by contamination of their food supply. A honey bee queen may lay 2000 eggs per day during spring buildup, but she also must lay 1000 to 1500 eggs per day during the foraging season, mostly to replace daily casualties, most of which are workers dying of old age. Among solitary and primitively social bees, however, lifetime reproduction is among the lowest of all insects, as it is common for females of such species to produce fewer than 25 offspring. The population value of bees depends partly on the individual efficiency of the bees, but also on the population itself. Thus, while bumblebees have been found to be about ten times more efficient pollinators on cucurbits, the total efficiency of a colony of honey bees is much greater, due to greater numbers. Likewise, during early spring orchard blossoms, bumblebee populations are limited to only a few queens, and thus are not significant pollinators of early fruit. Depopulation. Recently, managed populations of European honey bees have experienced substantial declines. This has prompted investigations into the phenomenon amidst great concern over the nature and extent of the losses. One aspect of the problem is believed to be "Colony Collapse Disorder" but many of the losses outside the US are attributed to other causes. Pesticides used to treat seeds, such as Clothianidin and Imidacloprid, may also negatively impact honey bee populations. Other species of bees such as mason bees are increasingly cultured and used to meet the agricultural pollination need. Most native pollinators are solitary bees, which often survive in refuge in wild areas away from agricultural spraying, but may still be poisoned in massive spray programs for mosquitoes, gypsy moths, or other insect pests. Evolution. Bees, like ants, are a specialized form of wasp. The ancestors of bees were wasps in the family Crabronidae, and therefore predators of other insects. The switch from insect prey to pollen may have resulted from the consumption of prey insects that were flower visitors and were partially covered with pollen when they were fed to the wasp larvae. This same evolutionary scenario has also occurred within the vespoid wasps, where the group known as "pollen wasps" also evolved from predatory ancestors. Up until recently the oldest non-compression bee fossil had been "Cretotrigona prisca" in New Jersey amber and of Cretaceous age, a meliponine. A recently reported bee fossil, of the genus "Melittosphex", is considered "an extinct lineage of pollen-collecting Apoidea sister to the modern bees", and dates from the early Cretaceous (~100 mya). Derived features of its morphology ("apomorphies") place it clearly within the bees, but it retains two unmodified ancestral traits ("plesiomorphies") of the legs (two mid-tibial spurs, and a slender hind basitarsus), indicative of its transitional status. The earliest animal-pollinated flowers were pollinated by insects such as beetles, so the syndrome of insect pollination was well established before bees first appeared. The novelty is that bees are "specialized" as pollination agents, with behavioral and physical modifications that specifically enhance pollination, and are generally more efficient at the task than beetles, flies, butterflies, pollen wasps, or any other pollinating insect. The appearance of such floral specialists is believed to have driven the adaptive radiation of the angiosperms, and, in turn, the bees themselves. Among living bee groups, the Dasypodaidae are now considered to be the most "primitive", and sister taxon to the remainder of the bees, contrary to earlier hypotheses that the "short-tongued" bee family Colletidae was the basal group of bees; the short, wasp-like mouthparts of colletids are the result of convergent evolution, rather than indicative of a plesiomorphic condition. Eusocial and semisocial bees. Bees may be solitary or may live in various types of communities. The most advanced of these are eusocial colonies found among the honey bees, bumblebees, and stingless bees. Sociality, of several different types, is believed to have evolved separately many times within the bees. In some species, groups of cohabiting females may be sisters, and if there is a division of labor within the group, then they are considered semisocial. If, in addition to a division of labor, the group consists of a mother and her daughters, then the group is called eusocial. The mother is considered the "queen" and the daughters are "workers". These castes may be purely behavioral alternatives, in which case the system is considered "primitively eusocial" (similar to many paper wasps), and if the castes are morphologically discrete, then the system is "highly eusocial". There are many more species of primitively eusocial bees than highly eusocial bees, but they have rarely been studied. The biology of most such species is almost completely unknown. The vast majority are in the family Halictidae, or "sweat bees". Colonies are typically small, with a dozen or fewer workers, on average. The only physical difference between queens and workers is average size, if they differ at all. Most species have a single season colony cycle, even in the tropics, and only mated females (future queens, or "gynes") hibernate (called diapause). A few species have long active seasons and attain colony sizes in the hundreds. The orchid bees include a number of primitively eusocial species with similar biology. Certain species of allodapine bees (relatives of carpenter bees) also have primitively eusocial colonies, with unusual levels of interaction between the adult bees and the developing brood. This is "progressive provisioning"; a larva's food is supplied gradually as it develops. This system is also seen in honey bees and some bumblebees. Highly eusocial bees live in colonies. Each colony has a single queen, many workers and, at certain stages in the colony cycle, drones. When humans provide the nest, it is called a hive. A honey bee hive can contain up to 40,000 bees at their annual peak, which occurs in the spring, but usually have fewer. Bumblebees. Bumblebees ("Bombus terrestris", "B. pratorum", et al.) are eusocial in a manner quite similar to the eusocial Vespidae such as hornets. The queen initiates a nest on her own (unlike queens of honey bees and stingless bees which start nests via swarms in the company of a large worker force). Bumblebee colonies typically have from 50 to 200 bees at peak population, which occurs in mid to late summer. Nest architecture is simple, limited by the size of the nest cavity (pre-existing), and colonies are rarely perennial. Bumblebee queens sometimes seek winter safety in honey bee hives, where they are sometimes found dead in the spring by beekeepers, presumably stung to death by the honey bees. It is unknown whether any survive winter in such an environment. Stingless bees. Stingless bees are very diverse in behavior, but all are highly eusocial. They practice mass provisioning, complex nest architecture, and perennial colonies. Honey bees. The true honey bees (genus "Apis") have arguably the most complex social behavior among the bees. The European (or Western) honey bee, "Apis mellifera", is the best known bee species and one of the best known of all insects. Africanized honey bee. Africanized bees, also called killer bees, are a hybrid strain of "Apis mellifera" derived from experiments to cross European and African honey bees by Warwick Estevam Kerr. Several queen bees escaped his laboratory in South America and have spread throughout the Americas. Africanized honey bees are more defensive than European honey bees. Solitary and communal bees. Most other bees, including familiar species of bee such as the Eastern carpenter bee ("Xylocopa virginica"), alfalfa leafcutter bee ("Megachile rotundata"), orchard mason bee ("Osmia lignaria") and the hornfaced bee ("Osmia cornifrons") are solitary in the sense that every female is fertile, and typically inhabits a nest she constructs herself. There are no "worker" bees for these species. Solitary bees typically produce neither honey nor beeswax. They are immune from acarine and "Varroa" mites (see diseases of the honey bee), but have their own unique parasites, pests and diseases. Solitary bees are important pollinators, and pollen is gathered for provisioning the nest with food for their brood. Often it is mixed with nectar to form a paste-like consistency. Some solitary bees have very advanced types of pollen carrying structures on their bodies. A very few species of solitary bees are being increasingly cultured for commercial pollination. Solitary bees are often oligoleges, in that they only gather pollen from one or a few species genera of plants (unlike honey bees and bumblebees which are generalists). No known bees are nectar specialists; many oligolectic bees will visit multiple plants for nectar, but there are no bees which visit only one plant for nectar while also gathering pollen from many different sources. Specialist pollinators also include bee species that gather floral oils instead of pollen, and male orchid bees, which gather aromatic compounds from orchids (one of the only cases where male bees are effective pollinators). In a very few cases only one species of bee can effectively pollinate a plant species, and some plants are endangered at least in part because their pollinator is dying off. There is, however, a pronounced tendency for oligolectic bees to be associated with common, widespread plants which are visited by multiple pollinators (e.g., there are some 40 oligoleges associated with creosotebush in the US desert southwest, and a similar pattern is seen in sunflowers, asters, mesquite, etc.) Solitary bees create nests in hollow reeds or twigs, holes in wood, or, most commonly, in tunnels in the ground. The female typically creates a compartment (a "cell") with an egg and some provisions for the resulting larva, then seals it off. A nest may consist of numerous cells. When the nest is in wood, usually the last (those closer to the entrance) contain eggs that will become males. The adult does not provide care for the brood once the egg is laid, and usually dies after making one or more nests. The males typically emerge first and are ready for mating when the females emerge. Providing nest boxes for solitary bees is increasingly popular for gardeners. Solitary bees are either stingless or very unlikely to sting (only in self defense, if ever). While solitary females each make individual nests, some species are gregarious, preferring to make nests near others of the same species, giving the appearance to the casual observer that they are social. Large groups of solitary bee nests are called "aggregations", to distinguish them from colonies. In some species, multiple females share a common nest, but each makes and provisions her own cells independently. This type of group is called "communal" and is not uncommon. The primary advantage appears to be that a nest entrance is easier to defend from predators and parasites when there are multiple females using that same entrance on a regular basis. Cleptoparasitic bees. Cleptoparasitic bees, commonly called "cuckoo bees" because their behavior is similar to cuckoo birds, occur in several bee families, though the name is technically best applied to the apid subfamily Nomadinae. Females of these bees lack pollen collecting structures (the scopa) and do not construct their own nests. They typically enter the nests of pollen collecting species, and lay their eggs in cells provisioned by the host bee. When the cuckoo bee larva hatches it consumes the host larva's pollen ball, and if the female cleptoparasite has not already done so, kills and eats the host larva. In a few cases where the hosts are social species, the cleptoparasite remains in the host nest and lays many eggs, sometimes even killing the host queen and replacing her. Many cleptoparasitic bees are closely related to, and resemble, their hosts in looks and size, (i.e., the "Bombus" subgenus "Psithyrus", which are parasitic bumblebees that infiltrate nests of species in other subgenera of "Bombus"). This common pattern gave rise to the ecological principle known as "Emery's Rule". Others parasitize bees in different families, like "Townsendiella", a nomadine apid, one species of which is a cleptoparasite of the dasypodaid genus "Hesperapis", while the other species in the same genus attack halictid bees. Nocturnal bees. Four bee families (Andrenidae, Colletidae, Halictidae, and Apidae) contain some species that are crepuscular (these may be either the vespertine or matinal type). These bees have greatly enlarged ocelli, which are extremely sensitive to light and dark, though incapable of forming images. Many are pollinators of flowers that themselves are crepuscular, such as evening primroses, and some live in desert habitats where daytime temperatures are extremely high. Bee flight. In his 1934 French book "Le vol des insectes", M. Magnan wrote that he and a Mr. Saint-Lague had applied the equations of air resistance to bumblebees and found that their flight could not be explained by fixed-wing calculations, but that "One shouldn't be surprised that the results of the calculations don't square with reality". This has led to a common misconception that bees "violate aerodynamic theory", but in fact it merely confirms that bees do not engage in fixed-wing flight, and that their flight is explained by other mechanics. In 1996 Charlie Ellington at Cambridge University showed that vortices created by many insects’ wings and non-linear effects were a vital source of lift; vortices and non-linear phenomena are notoriously difficult areas of hydrodynamics, which has made for slow progress in theoretical understanding of insect flight. In 2005 Michael Dickinson and his Caltech colleagues studied honey bee flight with the assistance of high-speed cinematography and a giant robotic mock-up of a bee wing. Their analysis revealed sufficient lift was generated by "the unconventional combination of short, choppy wing strokes, a rapid rotation of the wing as it flops over and reverses direction, and a very fast wing-beat frequency". Wing beat frequency normally increases as size decreases, but as the bee's wing beat covers such a small arc, it flaps approximately 230 times per second, faster than a fruitfly (200 times per second) which is 80 times smaller. In 2008 Barbara Shipman discovered a mathematical connection between the dance of bees and the Flag manifold. Bees and humans. Bees figure prominently in mythology (See Bee (mythology)) and have been used by political theorists as a model for human society. Journalist Bee Wilson states that the image of a community of honey bees "occurs from ancient to modern times, in Aristotle and Plato; in Virgil and Seneca; in Erasmus and Shakespeare; Tolstoy, as well as by social theorists Bernard Mandeville and Karl Marx." Despite the honey bee's painful sting and the stereotype of insects as pests, bees are generally held in high regard. This is most likely due to their usefulness as pollinators and as producers of honey, their social nature, and their reputation for diligence. Bees are one of the few insects regularly used on advertisements, being used to illustrate honey and foods made with honey (such as Honey Nut Cheerios). In North America, yellowjackets and hornets, especially when encountered as flying pests, are often misidentified as bees, despite numerous differences between them; see Characteristics of common wasps and bees. Although a bee sting can be deadly to those with allergies, virtually all bee species are non-aggressive if undisturbed and many cannot sting at all. Humans are often a greater danger to bees, as bees can be affected or even harmed by encounters with toxic chemicals in the environment; see Bees and toxic chemicals.