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Ataxia–telangiectasia
Ataxia–telangiectasia (AT or A–T), also referred to as ataxia–telangiectasia syndrome or Louis–Bar syndrome, is a rare, neurodegenerative disease causing severe disability. Ataxia refers to poor coordination and telangiectasia to small dilated blood vessels, both of which are hallmarks of the disease. A–T affects many parts of the body: * It impairs certain areas of the brain including the cerebellum, causing difficulty with movement and coordination. * It weakens the immune system, causing a predisposition to infection. * It prevents the repair of broken DNA, increasing the risk of cancer. Symptoms most often first appear in early childhood (the toddler stage) when children begin to sit or walk. Though they usually start walking at a normal age, they wobble or sway when walking, standing still, or sitting. In late pre-school and early school age, they develop difficulty moving their eyes in a natural manner from one place to the next (oculomotor apraxia). They develop sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Personal Computer/AT
The IBM Personal Computer AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 80286 microprocessor. Name IBM did not specify an expanded form of ''AT'' on the machine, press releases, brochures or documentation, but some sources expand the term as ''Advanced Technology'', including at least one internal IBM document. History IBM's 1984 introduction of the AT was seen as an unusual move for the company, which typically waited for competitors to release new products before producing its own models. At $4,000–6,000, it was only slightly more expensive than considerably slower IBM models. The announcement surprised rival executives, who admitted that matching IBM's prices would be difficult. No major competitor showed a comparable computer at COMDEX Las Vegas that year. Features The AT is IBM PC compatible, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appalachian Trail
The Appalachian Trail, also called the A.T., is a hiking trail in the Eastern United States, extending almost between Springer Mountain in Georgia and Mount Katahdin in Maine, and passing through 14 states.Gailey, Chris (2006)"Appalachian Trail FAQs" Outdoors.org (accessed September 14, 2006) The Appalachian Trail Conservancy claims the Appalachian Trail to be the world's longest hiking-only trail. More than three million people hike segments of it each year. The trail was first proposed in 1921 and completed in 1937. Improvements and changes have continued since then. It became the Appalachian National Scenic Trail under the National Trails System, National Trails System Act of 1968. The trail is maintained by 31 trail clubs and multiple partnerships and managed by the National Park Service, United States Forest Service, and the nonprofit Appalachian Trail Conservancy. Most of the trail is in forest or wild lands, but some parts traverse towns, roads, and farms. From south t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hayes Command Set
The Hayes command set (also known as the AT command set) is a specific command language originally developed by Dale Heatherington and Dennis Hayes for the Hayes Smartmodem in 1981. The command set consists of a series of short text strings which can be combined to produce commands for operations such as dialing, hanging up, and changing the parameters of the connection. The vast majority of dial-up modems use the Hayes command set in numerous variations. The command set covered only those operations supported by the earliest modems. When new commands were required to control additional functionality in higher speed modems, a variety of one-off standards emerged from each of the major vendors. These continued to share the basic command structure and syntax, but added any number of new commands using some sort of prefix character for Hayes and USRobotics, and for Microcom, for instance. Many of these were re-standardized on the Hayes extensions after the introduction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT (form Factor)
In the era of IBM compatible personal computers, the AT form factor comprises the dimensions and layout (Comparison of computer form factors, form factor) of the motherboard for the IBM AT. Baby AT motherboards are slightly smaller, measuring 8.5" by 13". Like the IBM PC and IBM XT models before it, many third-party manufacturers produced motherboards Interoperability, compatible with the IBM AT form factor, allowing end users to Computer hardware#Hardware_upgrade, upgrade their computers for faster Processor (computing), processors. The IBM AT became a widely copied design in the booming home computer market of the 1980s. IBM clones made at the time began using AT compatible designs, contributing to its popularity. In the 1990s many computers still used AT and its variants. Since 1997, the AT form factor has been largely supplanted by ATX. Design The original AT motherboard, later known as "Full AT", is , which means it will not fit in "mini desktop" or "minitower cases". The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
