The Effective Size of a Metapopulation Living in a Heterogeneous Patch Network

2002 ◽  
Vol 160 (5) ◽  
pp. 612 ◽  
Author(s):  
Ovaskainen
Keyword(s):  
Effective Size ◽  
Patch Network

scholarly journals Parametrizations of Liquid and Ice Clouds’ Optical Properties in Operational Numerical Weather Prediction Models

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 89
Author(s):  
Harel. B. Muskatel ◽  
Ulrich Blahak ◽  
Pavel Khain ◽  
Yoav Levi ◽  
Qiang Fu
Keyword(s):  
Optical Properties ◽  
Numerical Weather Prediction ◽  
Radiation Transfer ◽  
Prediction Models ◽  
Weather Prediction ◽  
Effective Size ◽  
Asymmetry Factor ◽  
Numerical Weather ◽  
Numerical Weather Prediction Models ◽  
Spectral Averaging

Parametrization of radiation transfer through clouds is an important factor in the ability of Numerical Weather Prediction models to correctly describe the weather evolution. Here we present a practical parameterization of both liquid droplets and ice optical properties in the longwave and shortwave radiation. An advanced spectral averaging method is used to calculate the extinction coefficient, single scattering albedo, forward scattered fraction and asymmetry factor (bext, v, f, g), taking into account the nonlinear effects of light attenuation in the spectral averaging. An ensemble of particle size distributions was used for the ice optical properties calculations, which enables the effective size range to be extended up to 570 μm and thus be applicable for larger hydrometeor categories such as snow, graupel, and rain. The new parameterization was applied both in the COSMO limited-area model and in ICON global model and was evaluated by using the COSMO model to simulate stratiform ice and water clouds. Numerical weather prediction models usually determine the asymmetry factor as a function of effective size. For the first time in an operational numerical weather prediction (NWP) model, the asymmetry factor is parametrized as a function of aspect ratio. The method is generalized and is available on-line to be readily applied to any optical properties dataset and spectral intervals of a wide range of radiation transfer models and applications.

Population and Conservation Genetics of Marsupials

1989 ◽  
Vol 37 (3) ◽  
pp. 161 ◽  
Author(s):  
WB Sherwin ◽  
ND Murray
Keyword(s):  
Population Genetics ◽  
Conservation Genetics ◽  
Current Knowledge ◽  
Effective Size ◽  
Individual Species ◽  
Census Size ◽  
Electrophoretic Data ◽  
Marsupial Species ◽  
Small Effective Size ◽  
Census Number

This article summarises current knowledge of marsupial population genetics, and discusses its relevance to the conservation of marsupial species. It has been suggested that there is much lower genetic variation within marsupial populations than in eutherian mammals. This trend is not evident in the electrophoretic data summarised here. However, genetic differentiation between populations, subspecies, and species of marsupials appears to be slightly lower than comparable values for eutherians. Genetic estimates of migration between populations are scarce at present, but show values that are comparable with eutherians. Some studies of marsupial population genetics have used non-electrophoretic characteristics, or have addressed the possibility of selection on the characters analysed. Although few, these studies indicate the suitability of marsupials for such investigations. Recent debate over the theories and applications of conservation genetics has made it clear that more research is required on individual species. Given the record of extinction of marsupials in the last 200 years, it is important to test the applicability of these theories to individual marsupial species. Several examples are discussed emphasising the need for ecological studies that estimate the effective number of reproducing individuals per generation. This figure, called the effective size, is the corner- stone of conservation genetics theory, being an important determinant of both the rate of loss of variation between individuals, and the rate of inbreeding. The effective size of the mainland population of the eastern barred bandicoot, Perameles gunnii, appears to be only about one-tenth of its census number. This result is comparable with estimates made in other vertebrates, and demonstrates that many marsupial species which appear to have an adequate census size on ecological grounds may face genetic problems resulting from small effective size.

A Neutral Model With Fluctuating Population Size and Its Effective Size

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 381-388
Author(s):  
Masaru Iizuka ◽  
Hidenori Tachida ◽  
Hirotsugu Matsuda
Keyword(s):  
Asymptotic Behavior ◽  
Population Size ◽  
Diffusion Model ◽  
Arithmetic Mean ◽  
Harmonic Mean ◽  
Effective Size ◽  
Neutral Model ◽  
Average Heterozygosity ◽  
Special Case ◽  
Concrete Model

Abstract We consider a diffusion model with neutral alleles whose population size is fluctuating randomly. For this model, the effects of fluctuation of population size on the effective size are investigated. The effective size defined by the equilibrium average heterozygosity is larger than the harmonic mean of population size but smaller than the arithmetic mean of population size. To see explicitly the effects of fluctuation of population size on the effective size, we investigate a special case where population size fluctuates between two distinct states. In some cases, the effective size is very different from the harmonic mean. For this concrete model, we also obtain the stationary distribution of the average heterozygosity. Asymptotic behavior of the effective size is obtained when the population size is large and/or autocorrelation of the fluctuation is weak or strong.

scholarly journals Effective size of a trapped atomic Bose gas

2005 ◽  
Vol 72 (5) ◽  
Author(s):  
Wenxian Zhang ◽  
Z. Xu ◽  
L. You
Keyword(s):  
Bose Gas ◽  
Effective Size

Temperature driven interchange of the effective size of proton with deuterium

2021 ◽  
pp. 138775
Author(s):  
Rafał Topolnicki ◽  
Przemysław Dopieralski
Keyword(s):  
Effective Size

scholarly journals EFFECTIVE SIZE OF FLUCTUATING POPULATIONS WITH TWO SEXES AND OVERLAPPING GENERATIONS

Evolution ◽  
2007 ◽  
Vol 61 (8) ◽  
pp. 1873-1885 ◽  
Author(s):  
Steinar Engen ◽  
Thor Harald Ringsby ◽  
Bernt-Erik Saether ◽  
Russell Lande ◽  
Henrik Jensen ◽  
...  
Keyword(s):  
Overlapping Generations ◽  
Effective Size ◽  
Fluctuating Populations

scholarly journals Breeding strategy in small and closed livestock populations

2007 ◽  
Vol 23 (5-6-1) ◽  
pp. 269-275 ◽  
Author(s):  
V. Bogdanovic ◽  
R. Djedovic ◽  
P. Perisic ◽  
M.M. Petrovic
Keyword(s):  
Genetic Improvement ◽  
Breeding Strategy ◽  
Effective Size ◽  
Small Populations ◽  
Female Head ◽  
Animal Genetic Resources ◽  
Marginal Areas ◽  
The Family ◽  
Breeding Programmes ◽  
Commercial Breeding

This paper reviews the main characteristics of small and/or closed livestock populations. Although the emphasis during the realization of the genetic improvement in animal breeding is put on commercial breeding programmes, autochthonous breeds, races, strains, even herds of domestic animas, at the same time represent a potentially important segment for achieving the maintenance of the overall livestock production. These programmes are particularly important for the improvement of populations of animal genetic resources, as well as for the improvement of production in rural marginal areas. One of the main parameters for determining the size, and also the potential danger of a population is a so called effective size of the population (Ne). This parameter is determined according to the available number of male and female head of breeding stock in the population or in the herd and it varies under the influence of the sexes, changes in the size of the families, changes in the size of the population during time, as well as overlapping of the generations. Apart from the improvement of the economically important traits, the breeding programmes in small populations first of all must provide the increase of the effective size of the population aiming to limit or decrease the inbreeding, as well as the decrease of the variance in the size of the family. This is mainly achieved with so called "circular breeding plans" the sires being replaced by sons in the reproduction, and dams by daughters. The shortage of the generation interval by the change of the presence of some age categories i.e. larger number of young animals and animals that are at the peak of production comparing to a small number of older animals, can additionally influence on the genetic improvement of the traits.

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