Numeral systems
There is some evidence to suggest that early man may have used counting systems which consisted of "One, Two, Three" and thereafter "Many" to describe counting limits. Early peoples had a word to describe the quantities of one, two, and three but any quantity beyond was simply denoted as "Many". This is most likely based on the prevalence of this phenomenon among people in such disparate regions as the deep Amazon and Borneo jungles, where western civilizations explorers have historical records of their first encounters with these indigenous people. List of basic calculations
Science
The Roman numeral III stands for giant star in the Yerkes spectral classification scheme. Three is the atomic number of lithium. Three is the ASCII code of "End of Text". Three is the number of dimensions that humans can perceive. Humans perceive the universe to have three spatial dimensions, but some theories, such as string theory, suggest there are more. Three is the number of elementary fermion generations according to the Standard Model of particle physics. The triangle, a polygon with three edges and three vertices, is the most stable physical shape. For this reason it is widely utilized in construction, engineering and design. The ability of the human eye to distinguish colors is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. Humans being trichromatic, the retina contains three types of color receptor cells, or cones. There are three primary colors in the additive and subtractive models.
Argininosuccinic aciduria is an inherited disorder that causes the accumulation of argininosuccinic acid (also known as "ASA") in the blood and urine. Some patients may also have an elevation of ammonia, a toxic chemical, which can affect the nervous system. Argininosuccinic aciduria may become evident in the first few days of life because of high blood ammonia, or later in life presenting with "sparse" or "brittle" hair, developmental delay, and tremors. An infant with argininosuccinic aciduria may seem lethargic or be unwilling to eat, have poorly controlled breathing rate or body temperature, experience seizures or unusual body movements, or go into a coma. Complications from argininosuccinic aciduria may include developmental delay and mental retardation. Progressive liver damage, skin lesions, and brittle hair may also be seen. Immediate treatment and lifelong management (following a strict diet and using appropriate supplements) may prevent many of these complications. Occasionally, an individual may inherit a mild form of the disorder in which ammonia accumulates in the bloodstream only during periods of illness or other stress. Genetics
Mutations in the ASL gene cause argininosuccinic aciduria. Argininosuccinic aciduria belongs to a class of genetic diseases called urea cycle disorders. The urea cycle is a sequence of reactions in the cells of the liver. It processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys.In argininosuccinic aciduria, the enzyme argininosuccinate lyase, involved in the conversion of arginino succinate to arginine within the urea cycle, is damaged or missing.