BacteriaBacteria (bækˈtɪəriə; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere.
Natural competenceIn microbiology, genetics, cell biology, and molecular biology, competence is the ability of a cell to alter its genetics by taking up extracellular ("naked") DNA from its environment in the process called transformation. Competence may be differentiated between natural competence, a genetically specified ability of bacteria which is thought to occur under natural conditions as well as in the laboratory, and induced or artificial competence, which arises when cells in laboratory cultures are treated to make them transiently permeable to DNA.
Probabilistic latent semantic analysisProbabilistic latent semantic analysis (PLSA), also known as probabilistic latent semantic indexing (PLSI, especially in information retrieval circles) is a statistical technique for the analysis of two-mode and co-occurrence data. In effect, one can derive a low-dimensional representation of the observed variables in terms of their affinity to certain hidden variables, just as in latent semantic analysis, from which PLSA evolved.
Esophageal motility disorderAn esophageal motility disorder (EMD) is any medical disorder causing difficulty in swallowing, regurgitation of food and a spasm-type pain which can be brought on by an allergic reaction to certain foods. The most prominent one is dysphagia. Esophageal motility disorder may be a result of CREST syndrome, referring to the five main features: calcinosis, Raynaud syndrome, esophageal dysmotility, sclerodactyly and telangiectasia. Symptoms of EMD can include chest pain, and intermittent dysphagia for solids, liquids, or both, and regurgitation.
Latent Dirichlet allocationIn natural language processing, Latent Dirichlet Allocation (LDA) is a Bayesian network (and, therefore, a generative statistical model) that explains a set of observations through unobserved groups, and each group explains why some parts of the data are similar. The LDA is an example of a Bayesian topic model. In this, observations (e.g., words) are collected into documents, and each word's presence is attributable to one of the document's topics. Each document will contain a small number of topics.
Esophageal motility studyAn esophageal motility study (EMS) or esophageal manometry is a test to assess motor function of the upper esophageal sphincter (UES), esophageal body and lower esophageal sphincter (LES). An EMS is typically done to evaluate suspected disorders of motility or peristalsis of the esophagus. These include achalasia, diffuse esophageal spasm, nutcracker esophagus and hypertensive lower esophageal sphincter. These disorders typically present with dysphagia, or difficulty swallowing, usually to both solids and liquids even initially.
Economic mobilityEconomic mobility is the ability of an individual, family or some other group to improve (or lower) their economic status—usually measured in income. Economic mobility is often measured by movement between income quintiles. Economic mobility may be considered a type of social mobility, which is often measured in change in income. There are many different ideas in the literature as to what constitutes a good mathematical measure of mobility, each with their own advantages and drawbacks.
Personal computerA personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician. Unlike large, costly minicomputers and mainframes, time-sharing by many people at the same time is not used with personal computers. Primarily in the late 1970s and 1980s, the term home computer was also used.
Personal digital assistantA personal digital assistant (PDA), also known as a handheld PC, is a variety mobile device which functions as a personal information manager. PDAs have been mostly displaced by the widespread adoption of highly capable smartphones, in particular those based on iOS and Android, seeing a rapid decline in use after 2007. A PDA has an electronic visual display. Most models also have audio capabilities, allowing usage as a portable media player, and also enabling many of them to be used as telephones.
