DIGITAL TELEVISION |
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DTV can be used to carry more channels in the same amount of bandwidth than analog TV (6 MHz or 7 MHz in Europe) and to receive high-definition programming. The digital signal eliminates common analog broadcasting artifacts such as "ghosting", "snow", and static noises in audio. However, when the signal is transmitted at a too low data rate DTV replaces these artifacts with new MPEG compression artifacts, such as "blocking", and may fail to work entirely in situations where analog television would have produced an impaired but watchable picture. Depending on the sophistication and level of the error correction defined by the technical standard that the broadcaster complies with, DTV may either work perfectly or not work at all.
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FISHERIES |
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A fishery (plural: fisheries) is an organized effort by humans to catch fish or other aquatic species, an activity known as fishing. Generally, a fishery exists for the purpose of providing human food, although other aims are possible (such as sport or recreational fishing), or obtaining ornamental fish or fish products such as fish oil. Industrial fisheries are fisheries where the catch is not intended for direct human consumption (Castro and Huber 2003).
Regardless of purpose, however, the term fishery generally refers to a fishing effort centered on either a particular ecoregion or a particular species or type of fish or aquatic animal, and usually fisheries are differentiated by both criteria. Examples would be the salmon fishery of Alaska, the cod fishery off the Lofoten islands or the tuna fishery of the Eastern Pacific. Most fisheries are marine, rather than freshwater; most marine fisheries are based near the coast. This is not only because harvesting from relatively shallow waters is easier than in the open ocean, but also because fish are much more abundant near the coastal shelf, due to coastal upwelling and the abundance of nutrients available there.
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INTERNET |
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The Internet, or simply the Net, is the publicly accessible worldwide system of interconnected computer networks that transmit data by packet switching using a standardized Internet Protocol (IP). It is made up of thousands of smaller commercial, academic, domestic, and government networks. It carries various information and services, such as electronic mail, online chat, and the interlinked Web pages and other documents of the World Wide Web.
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SEMANTICS |
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Semantics is a subfield of linguistics that is traditionally defined as the study of meaning of (parts of) words, phrases, sentences, and texts. Semantics can be approached from a theoretical as well as an empirical (for example psycholinguistic and neuroscientific) point of view. The decompositional perspective towards meaning holds that the meaning of words can be analyzed by defining meaning atoms or primitives, which establish a language of thought. An area of study is the meaning of compounds, another is the study of relations between different linguistic expressions (homonymy, synonymy, antonymy, polysemy, paronyms, hypernymy, hyponymy, meronymy, metonymy, holonymy, exocentric, and endocentric). Semantics includes the study of thematic roles, argument structure, and its linking to syntax. Semantics deals with sense and reference, truth conditions, and discourse analysis. Pragmatics is often considered a part of semantics, but otherwise is treated as a branch of its own.
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