heterochrony
heterochrony Any change in the relative rates or timing of development of different cell lines in the body. Such changes can lead to significant alterations in form; for example, if a particular organ develops earlier or faster it may be larger. Hence, mutations causing such changes play an important role in evolution. Heterochronic changes affecting the relative rates of development of germ (reproductive) cells and somatic (body) cells are of particular interest. They fall into four categories –
acceleration,
progenesis,
neoteny, and
hypermorphosis – depending on whether the change in rate (speeded up or slowed down) affects the somatic tissues or the reproductive tissues (see table). However, they have only two possible outcomes: one is
paedomorphosis, in which reproduction occurs in an ancestrally juvenile form; the other is
peramorphosis, in which development is extended by the addition of stages to the sequence shown in the ancestral form.
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Classification of weapons and military equipment: problems and solutions.
Magazine article from: Military Thought; 5/1/2003; ; 700+ words
; ...various types of classifications and considered a...logical analysis of the classification and its relation...correctness of a classification," formal logic...construct and realize classifications with all their inherent...requirements to a classification's end result...
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Classification modulo invariance, with application to face recognition.
Magazine article from: Journal of Computational & Graphical Statistics; 12/1/2003; ; 700+ words
; ...dimension of the measurements in modern classification problems such as speech of image recognition...information about transformations to which classification should be invariant. For the face...relative to the camera. Ideally, the classification should be invariant with respect to...
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Revisiting classification and identification.
Magazine article from: Learning Disability Quarterly; 3/22/2005; ; 700+ words
; ...Scanlon suggested I discuss issues of classification and identification. I am pleased...with vagaries and inconsistencies in classification, definition, and identification...To muddle the problem further, classification problems are compounded by limited...
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Classification of soil texture based on wavelet domain singular values.(Technical report)
Magazine article from: International Journal of Tomography & Statistics; 6/22/2008; ; 700+ words
; ...packet transformation is proposed for classification of soil textures. A procedure for...WPNN) is employed for performing the classification. Compared to probabilistic neural...the proposed approach in terms of classification rate at various Peak Signal-to...
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Classification of digital libraries--an e-business model-based approach.
Magazine article from: Journal of Digital Information Management; 2/1/2008; ; 700+ words
; ...and portal features. Traditional classification schemes for digital libraries do not...we present a novel approach to the classification of digital libraries. It is based...information service providers. Our classification approach helps suppliers to communicate...
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Classification and low back pain: a review of the literature and critical analysis of selected systems.
Magazine article from: Physical Therapy; 7/1/1998; ; 700+ words
; Key words: Classification, Diagnosis, Low back pain. The concept of classification has recently gained interest among researchers...heterogeneous subgroups.[1,7] Interest in classification stems from the notion that this very large...
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Modified classification of xerophthalmia.(Original Article)(care and treatment)
Magazine article from: Indian Journal of Ophthalmology; 5/1/1991; ; 700+ words
; ...There are many classifications of xerophthalmia...present study all these classification have been exhaustively...objections to previous classifications have been raised...lacunae in the previous classifications, the following points...think over another classification. A clinician, who...
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Keeping classification current. (correctional institutions)
Magazine article from: Corrections Today; 7/1/1997; ; 700+ words
; ...Federal Bureau of Prison's (BOP) classification system. At that time, objective inmate classification as we know it today did not exist...discussions of criminal justice trends, classification systems are often forgotten. Issues...
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Classification and the dichotomous key: tools for teaching identification.(Report)
Magazine article from: The Science Teacher; 3/1/2009; ; 700+ words
; ...discuss how I approach and teach the concepts of classification and identification in my science classes. Simplifying tasks To introduce classification, I ask students for examples of how classification simplifies and organizes their everyday lives...
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Classification based on tree-structured allocation rules.(Report)
Magazine article from: The Journal of Experimental Education; 3/22/2008; ; 700+ words
; ...We developed this classification tree (trained) by...variable (diameter) for classification. Other characteristics...to further train the classification tree and provide better classifications. This might be us
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Classification of Disease
Encyclopedia entry from: Encyclopedia of Public Health
...and so on. Every classification has basic attributes...and epidemiology, classifications are designed primarily...The earliest use of classifications in public health...injuries. Later, as classifications were expanded to...version of the standard classification used in public health...
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Classification
Book article from: -Ologies and -Isms
83. Classification See also 288. NAMES ; 301. ORDER...biosystematy the science of the classification of living things. Also called biosystematics...into two parts for the purpose of classification. — dichotomist , n...
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Carnegie Classification System, the
Encyclopedia entry from: Encyclopedia of Education
...Carnegie Classification system was...studies. The Classifications were first...Revisions to the classifications were published...Carnegie Classification. An extensive...reservations. 1994 Classifications The 1994...Carnegie Classification comprised...
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occupational classification
Book article from: A Dictionary of Sociology
...Occupational classifications are essentially...Systems of classification vary according...deployed. Most classifications are developed...most common classification being the...x2019; classifications). The latest (1988) classification is based...
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Classification of Arts and Sciences, Early Modern
Dictionary entry from: New Dictionary of the History of Ideas
CLASSIFICATION OF ARTS AND SCIENCES, EARLY MODERN. The concept of classification seems obvious and benign. To classify is...inception in antiquity. The significance of classification lies not in what it means, but in how it...
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