scholarly journals Spatial and space-time correlations in systems of subpopulations with genetic drift and migration.

Genetics ◽  
1993 ◽  
Vol 133 (3) ◽  
pp. 711-727
Author(s):  
B K Epperson
Keyword(s):  
Population Genetics ◽  
Time Correlation ◽  
Space Time ◽  
Spatial Correlations ◽  
Gene Frequencies ◽  
Migration Patterns ◽  
Migration Rates ◽  
Space And Time ◽  
Time Correlations ◽  
And Migration

Abstract The geographic distribution of genetic variation is an important theoretical and experimental component of population genetics. Previous characterizations of genetic structure of populations have used measures of spatial variance and spatial correlations. Yet a full understanding of the causes and consequences of spatial structure requires complete characterization of the underlying space-time system. This paper examines important interactions between processes and spatial structure in systems of subpopulations with migration and drift, by analyzing correlations of gene frequencies over space and time. We develop methods for studying important features of the complete set of space-time correlations of gene frequencies for the first time in population genetics. These methods also provide a new alternative for studying the purely spatial correlations and the variance, for models with general spatial dimensionalities and migration patterns. These results are obtained by employing theorems, previously unused in population genetics, for space-time autoregressive (STAR) stochastic spatial time series. We include results on systems with subpopulation interactions that have time delay lags (temporal orders) greater than one. We use the space-time correlation structure to develop novel estimators for migration rates that are based on space-time data (samples collected over space and time) rather than on purely spatial data, for real systems. We examine the space-time and spatial correlations for some specific stepping stone migration models. One focus is on the effects of anisotropic migration rates. Partial space-time correlation coefficients can be used for identifying migration patterns. Using STAR models, the spatial, space-time, and partial space-time correlations together provide a framework with an unprecedented level of detail for characterizing, predicting and contrasting space-time theoretical distributions of gene frequencies, and for identifying features such as the pattern of migration and estimating migration rates in experimental studies of genetic variation over space and time.

Estimating Effective Population Size and Migration Rates From Genetic Samples Over Space and Time

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 429-446 ◽  
Author(s):  
Jinliang Wang ◽  
Michael C Whitlock
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Joint Estimation ◽  
Large Sample Size ◽  
Effective Population ◽  
Likelihood Methods ◽  
Marker Allele ◽  
Migration Rates ◽  
Space And Time ◽  
And Migration

Abstract In the past, moment and likelihood methods have been developed to estimate the effective population size (Ne) on the basis of the observed changes of marker allele frequencies over time, and these have been applied to a large variety of species and populations. Such methods invariably make the critical assumption of a single isolated population receiving no immigrants over the study interval. For most populations in the real world, however, migration is not negligible and can substantially bias estimates of Ne if it is not accounted for. Here we extend previous moment and maximum-likelihood methods to allow the joint estimation of Ne and migration rate (m) using genetic samples over space and time. It is shown that, compared to genetic drift acting alone, migration results in changes in allele frequency that are greater in the short term and smaller in the long term, leading to under- and overestimation of Ne, respectively, if it is ignored. Extensive simulations are run to evaluate the newly developed moment and likelihood methods, which yield generally satisfactory estimates of both Ne and m for populations with widely different effective sizes and migration rates and patterns, given a reasonably large sample size and number of markers.

scholarly journals Identification of the cosmogenic $$^{11}$$C background in large volumes of liquid scintillators with Borexino

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
M. Agostini ◽  
K. Altenmüller ◽  
S. Appel ◽  
V. Atroshchenko ◽  
Z. Bagdasarian ◽  
...  
Keyword(s):  
Solar Neutrino ◽  
Time Correlation ◽  
Space Time ◽  
Low Energy ◽  
High Multiplicity ◽  
Data Sets ◽  
Novel Technique ◽  
Energy Neutrino ◽  
Time Correlations ◽  
Neutrino Experiments

AbstractCosmogenic radio-nuclei are an important source of background for low-energy neutrino experiments. In Borexino, cosmogenic $$^{11}$$ 11 C decays outnumber solar pep and CNO neutrino events by about ten to one. In order to extract the flux of these two neutrino species, a highly efficient identification of this background is mandatory. We present here the details of the most consolidated strategy, used throughout Borexino solar neutrino measurements. It hinges upon finding the space-time correlations between $$^{11}$$ 11 C decays, the preceding parent muons and the accompanying neutrons. This article describes the working principles and evaluates the performance of this Three-Fold Coincidence (TFC) technique in its two current implementations: a hard-cut and a likelihood-based approach. Both show stable performances throughout Borexino Phases II (2012–2016) and III (2016–2020) data sets, with a $$^{11}$$ 11 C tagging efficiency of $$\sim 90$$ ∼ 90  % and $$\sim $$ ∼  63–66 % of the exposure surviving the tagging. We present also a novel technique that targets specifically $$^{11}$$ 11 C produced in high-multiplicity during major spallation events. Such $$^{11}$$ 11 C appear as a burst of events, whose space-time correlation can be exploited. Burst identification can be combined with the TFC to obtain about the same tagging efficiency of $$\sim 90\%$$ ∼ 90 % but with a higher fraction of the exposure surviving, in the range of $$\sim $$ ∼  66–68 %.

Population trends and migration patterns in the critically endangered Yellow-breasted Bunting (Emberiza aureola) in the Republic of Korea

2020 ◽  
Vol 27 (1) ◽  
pp. 56-63
Author(s):  
Jong-Gil Park ◽  
Chang-uk Park ◽  
Kyoung-Soon Jin ◽  
Yang-Mo Kim ◽  
Hee-Young Kim ◽  
...  
Keyword(s):  
Population Trends ◽  
Critically Endangered ◽  
Republic Of Korea ◽  
Migration Patterns ◽  
The Republic ◽  
And Migration

Espaço, Tempo e Modernidade

GEOgraphia ◽  
2009 ◽  
Vol 2 (3) ◽  
pp. 51
Author(s):  
Gilvan Luiz Hansen
Keyword(s):  
Modern Philosophy ◽  
Space Time ◽  
Space And Time ◽  
Time Concepts

Resumo Este artigo é uma discussão introdutória acerca da importância das concepções de espaço e tempo na modernidade. O objetivo deste texto é enfatizar os aspectos teóricos e práticos dos conceitos de espaço e tempo, mediante a apresentação de três perspectivas de interpretação desta questão na filosofia desenvolvida na modernidade. Palavras-chave: Modernidade, Espaço, Tempo, Filosofia Moderna, J. Habermas.Abstract This article is an introductory debate about the importance of space and time conceptions in modernity. The objective from this text is emphasize the theoretical and practical aspects of space and time concepts, by presentation of three interpretation perspectives of this question in the philosophy developed in modernity. Keywords: Modernity, Space, Time, Modern Philosophy, J. Habermas.

Samuel Beckett's Debt to Aristotle: Cosmology, Syllogism, Space, Time

2010 ◽  
Vol 22 (1) ◽  
pp. 181-195 ◽  
Author(s):  
Anthony Cordingley
Keyword(s):  
Trinity College ◽  
Space Time ◽  
Formal Logic ◽  
Trinity College Dublin ◽  
Space And Time ◽  
Creative Transformation ◽  
Cosmic Order

This essay argues for the presence of Aristotelian ideas of cosmic order, syllogism, space and time in Beckett's . It accounts for how such ideas impact upon the novel's 'I' as he attempts to offer a philosophical 'solution' to his predicament in an underworld divorced from the revolving heavens. Beckett's study of formal logic as a student at Trinity College, Dublin and his private study of philosophy in 1932 is examined in this light; particularly his “Philosophy Notes,” along with some possible further sources for his knowledge. The essay then reveals a creative transformation of Aristotelian ideas in which led to formal innovations, such as the continuous present of its narrative.

Distribution characteristics and migration patterns of hazardous trace elements in coal combustion products of power plants

Fuel ◽  
2019 ◽  
Vol 258 ◽  
pp. 116062 ◽  
Author(s):  
Jinxi Wang ◽  
Zhen Yang ◽  
Shenjun Qin ◽  
Balaji Panchal ◽  
Yuzhuang Sun ◽  
...  
Keyword(s):  
Trace Elements ◽  
Coal Combustion ◽  
Power Plants ◽  
Combustion Products ◽  
Distribution Characteristics ◽  
Migration Patterns ◽  
Coal Combustion Products ◽  
Hazardous Trace Elements ◽  
And Migration

scholarly journals On the computation of space-time correlations by large-eddy simulation

2004 ◽  
Vol 16 (11) ◽  
pp. 3859-3867 ◽  
Author(s):  
Guo-Wei He ◽  
Meng Wang ◽  
Sanjiva K. Lele
Keyword(s):  
Large Eddy Simulation ◽  
Space Time ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Time Correlations
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