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top 10 words in brain distribution (in article): animal wear light species century head design time type size |
top 10 words in brain distribution (in article): iron blade steel handle cut metal tool nail hammer hand |
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top 10 words in brain distribution (not in article): horse iron blade drink lamp steel wine handle beer wolf |
top 10 words in brain distribution (not in article): head hair whip breast size design sword century bra cell |
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times more probable under cat 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under knife (words not in the model) | |
| The cat'" ("Felis catus"), also known as the domestic cat'" or "'house cat'" to distinguish it from other felines and felids, is a small predatory carnivorous species of crepuscular mammal that is valued by humans for its companionship and its ability to hunt vermin, snakes, scorpions, and other unwanted household pests. It has been associated with humans for at least 9,500 years. A skilled predator, the cat is known to hunt over 1,000 species for food. It can be trained to obey simple commands. Individual cats have also been known to learn on their own to manipulate simple mechanisms, such as doorknobs. Cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. Cats may be the most popular pet in the world, with over 600 million in homes all over the world. They are also bred and shown as registered pedigree pets. This hobby is known as the "cat fancy." Until recently the cat was commonly believed to have been domesticated in ancient Egypt, where it was a cult animal. However a 2007 study found that the lines of descent of all house cats probably run through as few as five self-domesticating African Wildcats "(Felis silvestris lybica)" circa 8000 BC, in the Near East. Size. Cats typically weigh between 2.5 and 7 kg (5.5–16 pounds); however, some, such as the Maine Coon, can exceed. Some have been known to reach up to due to overfeeding. Conversely, very small cats (less than) have been reported. The largest cat ever was officially reported to have weighed in at about (46 lb 15.25 oz). The smallest cat ever officially recorded weighed around 3 lbs (1.36 kg). Cats average about in height and in head body length (males being larger than females), with tails averaging in length. Skeleton. Cats have 7 cervical vertebrae like almost all mammals, 13 thoracic vertebrae (humans have 12), 7 lumbar vertebrae (humans have 5), 3 sacral vertebrae like most mammals (humans have 5 because of their bipedal posture), and, except for Manx cats, 22 or 23 caudal vertebrae (humans have 3 to 5, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's enhanced spinal mobility and flexibility, compared with humans. The caudal vertebrae form the tail, used by the cat as a counterbalance to the body during quick movements. Cats also have free-floating clavicle bones, which allows them to pass their body through any space into which they can fit their heads. Mouth. Cats have highly specialized teeth for the killing of prey and the tearing of meat. The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently functions to shear meat like a pair of scissors. While this is present in canids, it is highly developed in felines. The cat's tongue has sharp spines, or papillae, useful for retaining and ripping flesh from a carcass. These papillae are small backward-facing hooks that contain keratin which also assist in their grooming. As facilitated by their oral structure, cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. Ears. Thirty-two individual muscles in each ear allow for a manner of directional hearing: a cat can move each ear independently of the other. Because of this mobility, a cat can move its body in one direction and point its ears in another direction. Most cats have straight ears pointing upward. Unlike dogs, flap-eared breeds are extremely rare (Scottish Folds are one such exceptional mutation.) When angry or frightened, a cat will lay back its ears, to accompany the growling or hissing sounds it makes. Cats also turn their ears back when they are playing, or to listen to a sound coming from behind them. The angle of cats' ears is an important clue to their mood. Legs. Cats, like dogs, are digitigrades. They walk directly on their toes, with the bones of their feet making up the lower part of the visible leg. Cats are capable of walking very precisely, because like all felines they directly register; that is, they place each hind paw (almost) directly in the print of the corresponding forepaw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain. Claws. Like nearly all members of family Felidae, cats have protractable claws. In their normal, relaxed position the claws are sheathed with the skin and fur around the toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hind feet. Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, "kneading", or for extra traction on soft surfaces (bedspreads, thick rugs, etc.). It is also possible to make a cooperative cat extend its claws by carefully pressing both the top and bottom of the paw. The curved claws may become entangled in carpet or thick fabric, which may cause injury if the cat is unable to free itself. Most cats have five claws on their front paws, and four or five on their rear paws. Because of an ancient mutation, however, domestic and feral cats are prone to polydactylyism, (particularly in the east coast of Canada and north east coast of the United States) and may have six or seven toes. The fifth front claw (the dewclaw) is proximal to the other claws. More proximally, there is a protrusion which appears to be a sixth "finger". This special feature of the front paws, on the inside of the wrists, is the carpal pad, also found on the paws of big cats and dogs. It has no function in normal walking, but is thought to be an anti-skidding device used while jumping. Skin. Cats possess rather loose skin; this allows them to turn and confront a predator or another cat in a fight, even when it has a grip on them. This is also an advantage for veterinary purposes, as it simplifies injections. In fact, the lives of cats with kidney failure can sometimes be extended for years by the regular injection of large volumes of fluid subcutaneously, which serves as an alternative to dialysis. The particularly loose skin at the back of the neck is known as the "scruff", and is the area by which a mother cat grips her kittens to carry them. As a result, cats tend to become quiet and passive when gripped there. This behavior also extends into adulthood, when a male will grab the female by the scruff to immobilize her while he mounts, and to prevent her from running away as the mating process takes place. This technique can be useful when attempting to treat or move an uncooperative cat. However, since an adult cat is heavier than a kitten, a pet cat should never be carried by the scruff, but should instead have its weight supported at the rump and hind legs, and at the chest and front paws. Often (much like a small child) a cat will lie with its head and front paws over a person's shoulder, and its back legs and rump supported under the person's arm. Senses. Cat senses are attuned for hunting. Cats have highly advanced hearing, eyesight, taste, and touch receptors, making the cat extremely sensitive among mammals. Cats' night vision is superior to humans although their vision in daylight is inferior. Cat eyes have a tapetum lucidum and cat eyes that are blue typically lack melanin and hence can show the red-eye effect (see odd-eyed cat). Humans and cats have a similar range of hearing on the low end of the scale, but cats can hear much higher-pitched sounds, up to 64 kHz, which is 1.6 octaves above the range of a human, and even one octave above the range of a dog. A domestic cat's sense of smell is about fourteen times as strong as a human's. Due to a mutation in an early cat ancestor, one of two genes necessary to taste sweetness may have been lost by the cat family. To aid with navigation and sensation, cats have dozens of movable vibrissae (whiskers) over their body, especially their face. Metabolism. Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually 12–16 hours, with 13–14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term "cat nap" refers to the cat's ability to fall asleep (lightly) for a brief period and has entered the English lexicon – someone who nods off for a few minutes is said to be "taking a cat nap". Due to their crepuscular nature, cats are often known to enter a period of increased activity and playfulness during the evening and early morning, dubbed the "evening crazies", "night crazies", "elevenses", or "mad half-hour" by some. The temperament of a cat can vary depending on the breed and socialization. Cats with oriental body types tend to be thinner and more active, while cats that have a cobby body type tend to be heavier and less active. The normal body temperature of a cat is between 38 and 39 °C (101 and 102.2 °F). A cat is considered febrile (hyperthermic) if it has a temperature of 39.5 °C (103 °F) or greater, or hypothermic if less than 37.5 °C (100 °F). For comparison, humans have a normal temperature of approximately 36.8 °C (98.6 °F). A domestic cat's normal heart rate ranges from 140 to 220 beats per minute, and is largely dependent on how excited the cat is. For a cat at rest, the average heart rate usually is between 150 and 180 bpm, about twice that of a human (average 80 bpm). Genetics. A 2007 study published in the journal "Science" asserts that all house cats are descended from a group of self-domesticating desert wildcats "Felis silvestris lybica" circa 10,000 years ago, in the Near East. The domesticated cat and its closest wild ancestor are both diploid organisms that possess 38 chromosomes, in which over 200 heritable genetic defects have been identified, many homologous to human inborn errors. Specific metabolic defects have been identified underlying many of these feline diseases. There are several genes responsible for the hair color identified. The combination of them gives different phenotypes. Features like hair length, lack of tail, or presence of a very short tail (bobtail cat) are also determined by single alleles and modified by polygenes. The Cat Genome Project, sponsored by the Laboratory of Genomic Diversity at the U.S. National Cancer Institute Frederick Cancer Research and Development Center in Frederick, Maryland, focuses on the development of the cat as an animal model for human hereditary disease, infectious disease, genome evolution, comparative research initiatives within the family Felidae, and forensic potential. All felines, including the big cats, have a genetic anomaly that may prevent them from tasting sweetness, which is a likely factor for their indifference to or avoidance of fruits, berries, and other sugary foods. Feeding and diet. Cats feed on small | A knife'" is a handheld sharp-edged instrument consisting of a handle attached to a blade that is used for cutting. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools. History. The earliest knives were shaped by knapping (percussive flaking) of rock, particularly harder rocks such as obsidian and flint. During the Paleolithic era Homo habilis likely made similar tools out of wood, bone, and similar perishable materials that have not survived. As recent as five thousand years ago, as advances in metallurgy progressed, stone, wood, and bone blades were gradually succeeded by copper, bronze, iron, and eventually steel. The first metal (copper) knives were symmetrical double edged daggers, which copied the earlier flint daggers. In Europe the first single edged knives appeared during the middle bronze age. Modern knives may be made from many different materials such as alloy tool steels, carbon fiber, ceramics, and titanium. Materials and construction. Today, knives come in many forms but can be generally categorized between two broad types: fixed blade knives and folding, or pocket, knives. Modern knives consist of a "blade" (1'") and "handle" (2'"). The blade edge can be plain or serrated or a combination of both. The handle, used to grip and manipulate the blade safely, may include the "tang", a portion of the blade that extends into the handle. Knives are made with partial (extending part way into the handle) and full (extending the full length of the handle, often visible on top and bottom) tangs. The handle can also include a bolster, which is a piece of material used to balance the knife, usually brass or other metal, at the front of the handle where it meets the blade. The blade consists of the "point" (3'"), the end of the knife used for piercing, the "edge" (4'"), the cutting surface of the knife extending from the point to the heel, the "grind" (5'"), the "cross-section" shape of the blade, the "spine", (6'"), the top, thicker portion of the blade, the "fuller" (7'"), the groove added to lighten the blade, and the "ricasso" (8'"), the thick portion of the blade joining the blade and the handle. The "guard" (9'") is a barrier between the blade and the handle which protects the hand from an opponent, or the blade of the knife itself. A "choil", where the blade is unsharpened and possibly indented as it meets the handle, may be used to prevent scratches to the handle when sharpening or as a forward-finger grip. The end of the handle, or "butt" (10'"), may allow a "lanyard" (11'"), used to secure the knife to the wrist, or a portion of the tang to protrude as a striking surface for pounding or glass breaking. Blade. Knife blades can be manufactured from a variety of materials, each of which has advantages and disadvantages. Carbon steel, an alloy of iron and carbon, can be very sharp, hold its edge well, and remain easy to sharpen, but is vulnerable to rust and stains. Stainless steel is an alloy of iron, chromium, possibly nickel, and molybdenum, with only a small amount of carbon. It is not able to take quite as sharp an edge as carbon steel, but is highly resistant to corrosion. High carbon stainless steel is stainless steel with a higher amount of carbon, intended to incorporate the better attributes of carbon steel and stainless steel. High carbon stainless steel blades do not discolor or stain, and maintain a sharp edge. Laminate blades use multiple metals to create a layered sandwich, combining the attributes of both. For example, a harder, more brittle steel may be sandwiched between an outer layer of softer, tougher, stainless steel to reduce vulnerability to corrosion. In this case, however, the part most affected by corrosion, the edge, is still vulnerable. Pattern-welding is similar to laminate construction. Layers of different steel types are welded together, but then the stock is manipulated to create patterns in the steel. Titanium is metal that has a better strength-to-weight ratio, is more wear resistant, and more flexible than steel. Although less hard and unable to take as sharp an edge, carbides in the titanium alloy allow them to be heat-treated to a sufficient hardness. Ceramic blades are hard, brittle, and lightweight: they may maintain a sharp edge for years with no maintenance at all. They are immune to common corrosion, and can only be sharpened on silicon carbide sandpaper and some grinding wheels. Plastic blades are not especially sharp and typically serrated. They are often disposable. Steel blades are commonly shaped by forging or stock removal. Forged blades are made by heating a single piece of steel, then shaping the metal while hot using a hammer or press. Stock removal blades are shaped by grinding and removing metal. With both methods, after shaping, the steel must be heat treated. This involves heating the steel above its critical point, then quenching the blade to harden it. After hardening, the blade is tempered to remove stresses and make the blade tougher. Mass manufactured kitchen cutlery uses both the forging and stock removal processes. Forging tends to be reserved for manufacturers' more expensive product lines, and can often be distinguished from stock removal product lines by the presence of an integral bolster, though integral bolsters can be crafted through either shaping method. Knives are sharpened in various ways. Flat ground blades have a profile that tapers from the thick spine to the sharp edge in a straight or convex line. Seen in cross section, the blade would form a long, thin triangle, or where the taper does not extend to the back of the blade, a long thin rectangle with one peaked side. Hollow ground blades have concave, beveled edges. The resulting blade has a thinner edge, so it may have better cutting ability for shallow cuts, but it is lighter and less durable than flat ground blades and will tend to bind in deep cuts. Serrated blade knives have a wavy, scalloped or saw-like blade. Serrated blades are more well suited for tasks that require aggressive 'sawing' motions, whereas plain edge blades are better suited for tasks that require push-through cuts (e.g., shaving, chopping). Fixed blade features. A fixed blade knife does not fold or slide, and is typically stronger due to the tang, the extension of the blade into the handle, and lack of moving parts. Folding blade features. A folding knife connects the blade to the handle through a pivot, allowing the blade to fold into the handle. To prevent injury to the knife user through the blade accidentally closing on the user's hand, folding knives typically have a locking mechanism. Different locking mechanisms are favored by various individuals for reasons such as perceived strength (lock safety), legality, and ease of use. Another prominent feature on many folding knives is the opening mechanism. Traditional pocket knives and Swiss Army Knives commonly employ the nail nick, while modern folding knives more often use a stud, hole, disk, or "flipper" located on the blade, all which have the benefit of allowing the user to open the knife with one hand. "Automatic" or "switchblade" knives open using the stored energy from a spring that is released when the user presses a button or lever or other actuator built into the handle of the knife. Automatic knives are popular amongst law enforcement and military users for their ease of rapid deployment and their ability to be opened using only one hand. Automatic knives are severely restricted by law in most states. Increasingly common are "assisted opening" knives which use springs to propel the blade once the user has moved it past a certain angle. These differ from automatic or switchblade knives in that the blade is not released by means of a button or catch on the handle; rather, the blade itself is the actuator. Most assisted openers use flippers as their opening mechanism. Assisted opening knives can be as fast or faster than automatic knives to deploy. Sliding blade features. A sliding knife is a knife which can be opened by sliding the knife blade out the front of the handle. One method of opening is where the blade exits out the front of the handle point-first and then is locked into place (an example of the this is the gravity knife). Another form is a O-T-F (out-the-front) switchblade, which only requires the push of a button or spring to cause the blade to slide out of the handle, and lock into place. To retract the blade back into the handle, a release lever or button, usually the same control as to open, is pressed. A very common form of sliding knife is the sliding utility knife (commonly known as a stanley knife). Handle. The handles of knives can be made from a number of different materials, each of which has advantages and disadvantages. Handles are produced in a wide variety of shapes and styles. Handles are often textured to enhance grip. More exotic materials usually only seen on art or ceremonial knives include: Stone, bone, mammoth tooth, mammoth ivory, oosic (walrus penis bone), walrus tusk, antler (often called stag in a knife context), sheep horn, buffalo horn, teeth, etc. Many materials have been employed in knife handles. Knives as weapons. As a weapon, the knife is universally adopted as an essential tool. For example: Knives as utensils. A primary aspect of the knife as a tool includes dining, used either in food preparation or as cutlery. Examples of this include: Knives as tools. As a utility tool the knife can take many forms, including: Rituals and superstitions. The knife plays a significant role in some cultures through ritual and superstition, as the knife was an essential tool for survival since early man. Knife symbols can be found in various cultures to symbolize all stages of life; for example, a knife placed under the bed while giving birth is said to ease the pain, or, stuck into the headboard of a cradle, to protect the baby.; knives were included in some Anglo-Saxon burial rites, so the dead would not be defenseless in the next world. The knife plays an important role in some initiation rites, and many cultures perform rituals with a variety of knives, including the ceremonial sacrifices of animals. Samurai warriors, as part of bushido, could perform ritual suicide, or seppuku, with a tantō, a common Japanese knife. An athame, a ceremonial black-handled knife, is used in Wicca and derived forms of neopagan witchcraft. In Greece a black-handled knife placed under the pillow is used to keep away nightmares. As early as 1646 reference is made to a superstition of laying a knife across another piece of cutlery being a sign of witchcraft. A common belief is that if a knife is given as a gift, the relationship of the giver and recipient will be severed. Something such as a small coin or dove is exchanged for the gift, rendering "payment." Legislation. Knives are typically restricted by law, although restrictions vary greatly by country or state and type of knife. For example, some laws restrict carrying an unconcealed knife in public while other laws can restrict even private ownership of certain knives, such as switchblades. |