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Retention Cyst
Retention may refer to: General * Recall (memory), in learning, the ability to recall facts and figures in memory * Memory and retention in learning * Selective retention * Cultural retention * Customer retention * University student retention * Employee retention, the ability to keep employees within an organization * Forced retention * Grade retention, in schools, keeping a student in the same grade for another year (that is, not promoting the student to the next higher grade with his/her classmates) * Retention basin, * Retention election, in the United States court system, a process whereby a judge is periodically subject to a vote in order to remain in the position of judge * Retention rate * Retention ratio, in company earnings * Retention of vision, in magic * Water retention (medicine), abnormal accumulation of fluid in the body * Urinary retention, the lack or inability to urinate * Variable retention, in land management and forestry conservation Information and record ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recall (memory)
Recall in memory refers to the mental process of retrieval of information from the past. Along with encoding and storage, it is one of the three core processes of memory. There are three main types of recall: free recall, cued recall and serial recall. Psychologists test these forms of recall as a way to study the memory processes of humansrecall. (2010). In Encyclopædia Britannica. Retrieved March 04, 2010, from Encyclopædia Britannica Online: http://www.britannica.com/EBchecked/topic/493353/recal/ref> and animals. Two main theories of the process of recall are the two-stage theory and the theory of Encoding specificity principle, encoding specificity. Theories Two-stage theory The ''two-stage theory'' states that the process of recall begins with a search and retrieval process, and then a decision or recognition process where the correct information is chosen from what has been retrieved. In this theory, recognition only involves the latter of these two stages, or processes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Retention
Variable retention is a relatively new silvicultural system that retains forest structural elements for at least one rotation in order to preserve environmental values associated with structurally complex forests. Some examples for environmental values are forest cover connectivity, soil stabilization, microclimate under retained trees, habitats associated with live or dead trees and species diversity due to habitat preservation, and wildlife corridor preservation. Variable retention also aids in emulation of natural disturbances by leaving behind some residual structure from previous stand which is typical for stand replacing disturbances Traditional silviculture systems such as clearcut, patch cut, shelterwood, etc. are focused on maximizing timber production and future regeneration of the trees. Variable retention on the other hand is focused on what is retained Value of variable retention Variable retention is gradually becoming a popularly promoted tool for helping resolve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retention Uniformity
Retention uniformity, or ''RU'', is a concept in thin layer chromatography. It is designed for the quantitative measurement of ''equal-spreading'' of the spots on the chromatographic plate and is one of the Chromatographic response functions. Formula Retention uniformity is calculated from the following formula: R_ = 1 - \sqrt{\frac{6(n+1)}{n(2n+1)}\sum_{i=1}^{n}{\left(R_{Fi}-\frac{i}{n+1}\right)^2 where ''n'' is the number of compounds separated, ''Rf (1...n)'' are the Retention factor In chromatography, the retardation factor (''R'') is the fraction of an analyte An analyte, component (in clinical chemistry), or chemical species is a substance or chemical constituent that is of interest in an analytical procedure. The purest ... of the compounds sorted in non-descending order. Theoretical considerations The coefficient lies always in range and 0 indicates worst case of separation (all Rf values equal to 0 or 1), value 1 indicates ideal equal-spreading of the spot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retention Distance
Retention distance, or ''RD'', is a concept in thin layer chromatography, designed for quantitative measurement of ''equal-spreading'' of the spots on the chromatographic plate and one of the Chromatographic response functions. It is calculated from the following formula: R_D = \Bigg n+1)^ \prod^n_ where ''n'' is the number of compounds separated, ''Rf (1...n)'' are the Retention factor of the compounds sorted in non-descending order, ''Rf0'' = 0 and ''Rf(n+1)'' = 1. Theoretical considerations The coefficient lies always in range and 0 indicates worst case of separation (all Rf values equal to 0 or 1), value 1 indicates ideal equal-spreading of the spots, for example (0.25,0.5,0.75) for three solutes, or (0.2,0.4,0.6,0.8) for four solutes. This coefficient was proposed as an alternative to earlier approaches, such as delta-Rf, delta-Rf product or MRF (Multispot Response Function). Besides its stable range, the advantage is a stable distribution as a random variable, rega ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retention Factor
In chromatography, the retardation factor (''R'') is the fraction of an analyte in the mobile phase of a chromatographic system. In planar chromatography in particular, the retardation factor ''R''F is defined as the ratio of the distance traveled by the center of a spot to the distance traveled by the solvent front. Ideally, the values for ''RF'' are equivalent to the R values used in column chromatography. Although the term retention factor is sometimes used synonymously with retardation factor in regard to planar chromatography the term is not defined in this context. However, in column chromatography, the retention factor or capacity factor (''k'') is defined as the ratio of time an analyte is retained in the stationary phase to the time it is retained in the mobile phase, which is inversely proportional to the retardation factor. General definition In chromatography, the retardation factor, ''R'', is the fraction of the sample in the mobile phase at equilibrium, defined as: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ER Retention
ER retention refers to proteins that are retained in the endoplasmic reticulum, or ER, after folding; these are known as ER resident proteins. Protein localization to the ER often depends on certain sequences of amino acids located at the N terminus or C terminus. These sequences are known as signal peptides, molecular signatures, or sorting signals. The classical ER retention signal is the C-terminal KDEL sequence for lumen bound proteins and KKXX (signal sequence is located in cytoplasm) for transmembrane localization. These signals allow for retrieval from the Golgi apparatus by ER retention receptors, effectively maintaining the protein in the ER. Other mechanisms for ER retention are being studied but are not as well characterized as signal retention. ER retention receptors proteins *KDELR1 *KDELR2 *KDELR3 See also * KKXX (amino acid sequence) * KDEL (amino acid sequence) * Signal peptide *Protein targeting :''This article deals with protein targeting in eukaryotes unless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retention Of Configuration
Walden inversion is the inversion of a stereogenic center in a chiral molecule in a chemical reaction. Since a molecule can form two enantiomers around a stereogenic center, the Walden inversion converts the configuration of the molecule from one enantiomeric form to the other. For example, in an SN2 reaction, Walden inversion occurs at a tetrahedral carbon atom. It can be visualized by imagining an umbrella turned inside-out in a gale. In the Walden inversion, the backside attack by the nucleophile in an SN2 reaction gives rise to a product whose configuration is opposite to the reactant. Therefore, during SN2 reaction, 100% inversion of product takes place. This is known as Walden inversion. It was first observed by chemist Paul Walden in 1896. He was able to convert one enantiomer of a chemical compound into the other enantiomer and back again in a so-called Walden cycle which went like this: (+) chlorosuccinic acid (1 in the illustration) was converted to (+) malic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CO₂ Retention
Hypercapnia (from the Greek ''hyper'' = "above" or "too much" and ''kapnos'' = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous product of the body's metabolism and is normally expelled through the lungs. Carbon dioxide may accumulate in any condition that causes hypoventilation, a reduction of alveolar ventilation (the clearance of air from the small sacs of the lung where gas exchange takes place) as well as resulting from inhalation of CO2. Inability of the lungs to clear carbon dioxide, or inhalation of elevated levels of CO2, leads to respiratory acidosis. Eventually the body compensates for the raised acidity by retaining alkali in the kidneys, a process known as "metabolic compensation". Acute hypercapnia is called acute hypercapnic respiratory failure (AHRF) and is a medical emergency as it generally occurs in the context of acute illness. Chronic hypercapn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retention Agent
A retention agent is a chemical process that improves the retention of a functional chemical in a substrate. The result is that totally fewer chemicals are used to get the same effect as the functional chemical and fewer chemicals go to waste. Applications Retention agents (retention aids) are used in the papermaking industry. These are added in the wet end of the paper machine to improve retention fine particles and fillers during the formation of paper. Retention aids can also be used to improve the retention of other papermaking chemicals, including sizing and cationic starches. The improved retention of papermaking furnish components improves the operational efficiency of the paper machine, reduces the solids and organic loading in the process water loop, and can lower overall chemical costs. Typical chemicals used as retention aids are: polyacrylamide (PAM), polyethyleneimine (PEI), colloidal silica, and bentonite. Retention Agents or Retention Aids are often used along with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Title Retention Clause
A retention of title clause (also called a reservation of title clause or a ''Romalpa'' clause in some jurisdictions) is a provision in a contract for the sale of goods that the title to the goods remains vested in the seller until the buyer fulfils certain obligations (usually payment of the purchase price). Purpose The main purpose of retention of title ("ROT" or "RoT") clauses is to ensure that where goods are supplied on credit, if the buyer subsequently goes into bankruptcy, the seller can repossess the goods. They are often seen as a natural extension of the credit economy; where suppliers are expected to sell goods on credit, there is a reasonable expectation that if they are not paid they should be able to repossess the goods. Nonetheless, in a number of jurisdictions, insolvency regimes or credit arrangement regimes prevent title retention clauses from being enforced where doing so would upset administration of the regime. Retention of title clauses are mandated in the E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retention Period
A retention period (associated with a retention schedule or retention program) is an aspect of records and information management (RIM) and the records life cycle that identifies the duration of time for which the information should be maintained or "retained," irrespective of format (paper, electronic, or other). Retention periods vary with different types of information, based on content and a variety of other factors, including internal organizational need, regulatory requirements for inspection or audit, legal statutes of limitation, involvement in litigation, and taxation and financial reporting needs, as well as other factors as defined by local, regional, state, national, and/or international governing entities. Once an applicable retention period has elapsed for a given type or series of information, and all holds/moratoriums have been released, the information is typically destroyed using an approved and effective destruction method, which renders the information completely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Data Retention
Data retention defines the policies of persistent data and records management for meeting legal and business data archival requirements. Although sometimes interchangeable, it is not to be confused with the Data Protection Act 1998. The different data retention policies weigh legal and privacy concerns against economics and need-to-know concerns to determine the retention time, archival rules, data formats, and the permissible means of storage, access, and encryption. In the field of telecommunications, data retention generally refers to the storage of call detail records (CDRs) of telephony and internet traffic and transaction data ( IPDRs) by governments and commercial organisations. In the case of government data retention, the data that is stored is usually of telephone calls made and received, emails sent and received, and websites visited. Location data is also collected. The primary objective in government data retention is traffic analysis and mass surveillance. By analy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
