Metric variations in populations of Carcinus moenas

1941 ◽  
Vol 25 (2) ◽  
pp. 261-281 ◽  
Author(s):  
G. Williams ◽  
A. E. Needham
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Carapace Length ◽  
Rate Of Change ◽  
The Other ◽  
Differential Growth ◽  
Moderate Amount ◽  
The Individual ◽  
Striking Fact ◽  
Selection Of

1. Measurements of Carcinus, comparable to those taken by Weldon at Plymouth 40 years ago, have been made on material from three Irish localities, the observations in each area extending over three years. The three localities afford different environments, one having no silt, one a moderate amount and the other much silt.2. The results support the view that the change in the ratio frontal width/ carapace length with increase in body size is due to differential growth in the individual and is not caused, as Weldon supposed, by the continuous removal through natural selection of those crabs with a relatively wide frontal aperture. Measurement on the growth of individuals confirms this view.3. A striking fact which emerged from Weldon's work was that the ratio mentioned above showed a successive diminution in each of the three years covered by the observations. A precisely similar diminution has been found at each of the Irish localities, and it is shown that the annual differences are mathematically significant.4. The results disprove Weldon's hypothesis that the change in the ratio is correlated with the slow accumulation of silt in Plymouth Sound. The Irish locality with most silt has the widest frontal aperture and the intermediate locality the narrowest. It is also shown that the yearly trend towards a lower value for the ratio cannot be continuous, for the rate of change is too rapid to be maintained indefinitely, and the values obtained in the Irish localities overlap those at Plymouth 40 years earlier. Possible explanations of the changes are discussed.5. The differences between populations from the three localities in any year are much less marked than the annual differences at one locality, and are not generally significant. Though small, however, they do show a consistent sequence among the three localities (but not corresponding to the order for siltiness).

Evidence for divergent natural selection of a Lake Tanganyika cichlid inferred from repeated radiations in body size

2009 ◽  
Vol 18 (14) ◽  
pp. 3110-3119 ◽  
Author(s):  
T. TAKAHASHI ◽  
K. WATANABE ◽  
H. MUNEHARA ◽  
L. RÜBER ◽  
M. HORI
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Lake Tanganyika ◽  
Divergent Natural Selection ◽  
Selection Of

thymos

2019 ◽  
Author(s):  
Douglas Cairns
Keyword(s):  
The Other ◽  
Psychological Process ◽  
Mental Functioning ◽  
Fundamental Point ◽  
The Individual ◽  
Psychological Activity ◽  
Different Order ◽  
Selection Of ◽  
Point Of Reference

Thymos (or thumos), cognate with Indo-European words meaning “smoke,” is one of a number of terms in Greek which associate psychological activity with air and breath. In the Homeric poems, thymos is one of a family of terms associated with internal psychological process of thought, emotion, volition, and motivation. Though the range of the term’s applications in Homer is wide, that in itself gives us a sense of the unity of cognitive, affective, and desiderative processes in Homeric psychology. No post-Homeric author can rival that range, but something of the richness of the Homeric conception of thymos as an interrelated set of motivations re-emerges in Plato’s conception of the tripartite soul in the Republic and the Phaedrus. Plato’s thymos represents a pared-down model of human agency typified by one central desire or aim in life but also exhibiting whatever further capacities of persons are necessary to enable it to pursue that aim in interaction with the other elements of the personality. As in Homer, the metaphorical agency of Plato’s thymos does not detract from the notion of the individual as the real centre of agency. Plato’s conception of thymos, in turn, is a fundamental point of reference for Aristotle’s treatment of thymos as a type of desire (orexis). Though Aristotle tends more generally to use the term as a synonym for orgē (anger), there are also traces of older associations between thymos and qualities such as assertiveness and goodwill towards others. Elsewhere, thymos tends to mean “heart” or “mind” (as aspects of mental functioning), “spirit,” “inclination,” or “anger.” A selection of these uses is surveyed, but the article overall concentrates on Homer, Plato, and Aristotle, where the role of thymos is of a different order of importance.

Research on the High-Power Directional Acoustic Transducer

2014 ◽  
Vol 912-914 ◽  
pp. 753-756
Author(s):  
Guo Zhu Zhao ◽  
Li Xuan Ma
Keyword(s):  
Rare Earth ◽  
Sound Source ◽  
Beam Width ◽  
Directivity Pattern ◽  
Acute Angle ◽  
The Other ◽  
Acoustic Transducer ◽  
Element Number ◽  
The Individual ◽  
Selection Of

Through studying how to affect acoustic directivity with MATLAB software, it show that selection of a relatively larger surface of the transducer and a relatively closer transducer interval will be more preferable for directivity. While an array which possess more array element number and whose frequency of the drive signal can be as large as possible in a range, directivity will be more preferable. On the other hand, when the structure of the sound radiating surface of the transducer or array layout is symmetrical, the corresponding directivity pattern will be symmetrical. At a frequency of 10kHz, the individual rare earth magnetostrictive transducers its first point of the simulation carried out before the test. Sounding board with aluminum by the method used to improve the sound source diameter. With the sound plate diameter incrementing, the smaller the angle of the directivity. The beam width of the 3×3 array is about at 23kHz, and the directivity acute angle is about 10°, with a sounding board by the method used to improve their the diameter of the sound source, so as to realize the sound has directivity is feasible.

Dynamic Analysis of Flexible Multi-Body Mechanical Systems

1996 ◽  
Vol 210 (4) ◽  
pp. 309-316
Author(s):  
P Davison ◽  
D K Longmore ◽  
C R Burrows
Keyword(s):  
Rate Of Change ◽  
The Other ◽  
Structural Deformation ◽  
Euler Parameters ◽  
Time Rate ◽  
Constraint Equations ◽  
Rigid Body Modes ◽  
The Individual ◽  
Multi Body ◽  
Flexible Component

The use of only the free component modes as coordinates when computing the motion of mechanisms involving flexible component structures connected together by driven or undriven joints has been further developed, with the constraint errors being controlled by penalty parameters related to both the errors and their time rate of change. Symbolic computation is used to incorporate the constraint equations into the solution program. The degenerate rigid-body modes may be indefinitely large, with Euler parameters being used for rotation, but the other free modes of the individual components, which involve structural deformation, are assumed small. The approach is examined in two examples in which the computed results are compared with experimental measurements.

scholarly journals Periodic Fluctuations in the Numbers of Animals: Their Causes and Effects

1924 ◽  
Vol 2 (1) ◽  
pp. 119-163 ◽  
Author(s):  
C. S. ELTON
Keyword(s):  
Natural Selection ◽  
Rapid Expansion ◽  
The Other ◽  
The Arctic ◽  
Arctic Regions ◽  
Biological Phenomena ◽  
Short Period ◽  
Periodic Fluctuations ◽  
Selection Of ◽  
New Mutations

I. Four main points are dealt with :-- (a) The widespread existence of fluctuations in the numbers of animals. (b) The existence, in many birds and mammals, of periodic fluctuations (p.f.). (c) The cause of the latter, which must be some periodic climatic change acting over wide areas. (d) The effects of fluctuations in general, and in particular of the p.f., on the method of evolution and other biological phenomena. 2. A short sketch is given of what is known about short- period climatic cycles (2 to 20 years), and their causes. 3. P.f. of lemmings have an average period of about 3½ years. The maxima in numbers occur synchronously in North America and Europe, and probably all round the arctic regions. The varying hare in Canada has a period of 10 to 11 years. 5. The only regular periods shown by the animals dealt with are the short one of 3½ years and the longer one of 10 to 11 years. The former is probably more marked in the arctic and the other further south. 6. The sandgrouse p.f. point to the existence of an 11-year climatic cycle in the deserts of Central Asia. 7. The effects of these p.f. on evolution must be very great, although at present problematical; but the following suggestions are made :-- (a) Natural selection of some characters must be periodic. (b) There will be different types of natural selection at the maxima and minima of numbers. (c) The struggle for existence, and therefore natural selection, tend to cease temporarily during the rapid expansion in numbers from a minimum, and new mutations have then a chance to get established and spread, i.e. without the aid of natural selection. This might happen only rarely. (d) This would explain the origin and survival of non adaptive characters in a species. (e) On the other hand periodic reduction in numbers will act as an important factor causing uniformity in the species. (f) The opposing factors (c) and (e) will vary much in different species, and the problem will require the combined attentions of mathematicians, and of ecologists working on the methods of regulation of the numbers of animals. (g) This mechanical uniformity factor, since it acts independently of natural selection, explains how a particular structure or habit may evolve, when it only has a general adaptive significance.

Gesture–speech unity

2014 ◽  
Vol 5 (2) ◽  
pp. 137-184 ◽  
Author(s):  
David McNeill
Keyword(s):  
Prefrontal Cortex ◽  
Natural Selection ◽  
Language Evolution ◽  
The Other ◽  
Shared Intentionality ◽  
Origin Of Language ◽  
Child Speech ◽  
The Brain ◽  
Shed Light ◽  
Selection Of

This paper outlines an argument for how development in child speech and gesture could shed light on language evolution: child acquisition can be thought of as two types of acquisition, one of which goes extinct (gesture-first, Acquisition 1) and is replaced by another (gesture–speech unity, Acquisition 2). For ontogenesis, this implies that children acquire two languages, one of which is extinct, and which again goes extinct in ontogenesis (it continues as “gestures of silence” rather than as gestures of speech). There is no way to get from Acquisition 1 to Acquisition 2. They are on different tracks. Even when they converge in the same sentence, as they sometimes do, they alternate and do not combine. I propose that the 3~4 year timing of Acquisition 2 relates to the natural selection of a kind of gestural self–response I call “Mead’s Loop”, which took place in a certain psychological milieu at the origin of language. This milieu emerges now in ontogenesis at 3~4 years and with it Mead’s Loop. It is self-aware agency, on which a self-response depends. Other developments, such as theory of mind and shared intentionality, likewise depend on it and also emerge around the same time. The prefrontal cortex, anchoring a ring of language centers in the brain, matures at that point as well, another factor influencing the late timing. On the other hand, a third acquisition, speech evoking adult attachment, begins at (or even before) birth, as shown by a number of studies, and provides continuity through the two acquisitions and extinction.

scholarly journals Updating Darwin: Information and entropy drive the evolution of life

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2808 ◽  
Author(s):  
Irun R. Cohen
Keyword(s):  
Natural Selection ◽  
The Other ◽  
Evolution Of Complexity ◽  
Programmed Death ◽  
Evolution Of Life ◽  
The One ◽  
Survival Of The Fittest ◽  
Darwinian Paradigm ◽  
Physical Principles ◽  
Selection Of

The evolution of species, according to Darwin, is driven by struggle – by competition between variant autonomous individuals for survival of the fittest and reproductive advantage; the outcome of this struggle for survival is natural selection. The Neo-Darwinians reframed natural selection in terms of DNA: inherited genotypes directly encode expressed phenotypes; a fit phenotype means a fit genotype – thus the evolution of species is the evolution of selfish, reproducing individual genotypes.  Four general characteristics of advanced forms of life are not easily explained by this Neo-Darwinian paradigm: 1) Dependence on cooperation rather than on struggle, manifested by the microbiome, ecosystems and altruism; 2) The pursuit of diversity rather than optimal fitness, manifested by sexual reproduction; 3) Life’s investment in programmed death, rather then in open-ended survival; and 4) The acceleration of complexity, despite its intrinsic fragility.   Here I discuss two mechanisms that can resolve these paradoxical features; both mechanisms arise from viewing life as the evolution of information. Information has two inevitable outcomes; it increases by autocatalyis and it is destroyed by entropy. On the one hand, the autocalalysis of information inexorably drives the evolution of complexity, irrespective of its fragility. On the other hand, only those strategic arrangements that accommodate the destructive forces of entropy survive – cooperation, diversification, and programmed death result from the entropic selection of evolving species. Physical principles of information and entropy thus fashion the evolution of life.

scholarly journals Globalne testy szkolne i ukryty program neoliberalnej kolonizacji

1970 ◽  
pp. 29-37
Author(s):  
Agnieszka Gromkowska-Melosik
Keyword(s):  
Public Good ◽  
Educational Policy ◽  
Hidden Curriculum ◽  
The Other ◽  
Culturally Different ◽  
Micro Level ◽  
The Individual ◽  
Equality In Education ◽  
National Governments ◽  
Selection Of

Tests have influence on the phenomenon of stratification and selection of students, their lifestyle and way of thinking. Without a doubt, they have their hidden curriculum. At the micro level tests shape the identity of the individual. They are a factor of socialization. On the other hand, at the macro level tests are the significant instrument of educational policy governments. In my article I analyse the second problem – in the context of international developments PISA tests, which are an instrument of neo-liberal policies of national governments, as well as the OECD. The tests are part of the abandonment of the idea of "equality in education" for the system market and competitiveness, in which education ceases to be a "public good" and becomes a "personal good." The essence of the hidden curriculum PISA test is the pursuit of homogenization student population living in culturally different countries as well as the shaping the attitudes of rivalry.

scholarly journals Processes and patterns of interaction as units of selection: An introduction to ITSNTS thinking

2018 ◽  
Vol 115 (16) ◽  
pp. 4006-4014 ◽  
Author(s):  
W. Ford Doolittle ◽  
S. Andrew Inkpen
Keyword(s):  
Natural Selection ◽  
Biogeochemical Cycles ◽  
The Other ◽  
Units Of Selection ◽  
Biological Hierarchy ◽  
Global Biogeochemical Cycles ◽  
Evolution By Natural Selection ◽  
Definition Of ◽  
Patterns Of Interaction ◽  
Selection Of

Many practicing biologists accept that nothing in their discipline makes sense except in the light of evolution, and that natural selection is evolution’s principal sense-maker. But what natural selection actually is (a force or a statistical outcome, for example) and the levels of the biological hierarchy (genes, organisms, species, or even ecosystems) at which it operates directly are still actively disputed among philosophers and theoretical biologists. Most formulations of evolution by natural selection emphasize the differential reproduction of entities at one or the other of these levels. Some also recognize differential persistence, but in either case the focus is on lineages of material things: even species can be thought of as spatiotemporally restricted, if dispersed, physical beings. Few consider—as “units of selection” in their own right—the processes implemented by genes, cells, species, or communities. “It’s the song not the singer” (ITSNTS) theory does that, also claiming that evolution by natural selection of processes is more easily understood and explained as differential persistence than as differential reproduction. ITSNTS was formulated as a response to the observation that the collective functions of microbial communities (the songs) are more stably conserved and ecologically relevant than are the taxa that implement them (the singers). It aims to serve as a useful corrective to claims that “holobionts” (microbes and their animal or plant hosts) are aggregate “units of selection,” claims that often conflate meanings of that latter term. But ITSNS also seems broadly applicable, for example, to the evolution of global biogeochemical cycles and the definition of ecosystem function.

Immunological assays of apolipoproteins in plasma: methods and instrumentation

1990 ◽  
Vol 36 (4) ◽  
pp. 591-597 ◽  
Author(s):  
C Labeur ◽  
J Shepherd ◽  
M Rosseneu
Keyword(s):  
Monoclonal Antibodies ◽  
Immunosorbent Assay ◽  
The Other ◽  
Antigenic Determinants ◽  
Enzyme Linked Immunosorbent Assay ◽  
Technical Details ◽  
Plasma Methods ◽  
Immunological Assays ◽  
The Individual ◽  
Selection Of

Abstract A number of immunological techniques--radioimmunoassay, enzyme-linked immunosorbent assay (ELISA), electroimmunoassay, radial immunodiffusion, and a variety of immunoprecipitin assays--have been used to quantify apolipoproteins in plasma. This paper outlines their technical details and discusses their major advantages and drawbacks. The most sensitive procedures, RIAs and ELISAS, are best suited to quantifying those apoproteins found in low concentration in plasma. Immunoturbidimetric assays, on the other hand, which are readily automated, are being widely used to quantify apolipoproteins A-I and B. Apolipoprotein quantification is complicated by the interaction of the proteins with lipids, which can often mask their antigenic determinants. This problem may be circumvented by pretreatment of the samples, by selection of appropriate standards, or by the use of polyclonal or monoclonal antibodies that interact with permanently exposed epitopes on the lipoproteins' surfaces. Our proposed methods for measurement of the individual apolipoproteins give consideration to these approaches.

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