scholarly journals Demographic models of the reproductive process: Past, interlude, and future

2021 ◽  
pp. 1-19
Author(s):  
Daniel Ciganda ◽  
Nicolas Todd
Keyword(s):  
Reproductive Process ◽  
Demographic Models

The specifics of shadow economic activity in Russia

2020 ◽  
Vol 19 (10) ◽  
pp. 1896-1915
Author(s):  
E.R. Ermakova ◽  
O.M. Lizina
Keyword(s):  
Economic Activity ◽  
Shadow Economy ◽  
Integrated Approach ◽  
Economic Activities ◽  
Reproductive Process ◽  
Scientific Methods ◽  
Current Period ◽  
Russian Economy ◽  
Analysis And Synthesis ◽  
The Impact

Subject. The article addresses the specifics of shadow economic activities in reformed Russia in the context of systemic transformations. Objectives. We focus on determining the role of shadow economy in the reproductive process, identifying and understanding the specifics of underground economic activity of the Russian economy. Methods. The study rests on general scientific methods (scientific abstraction, unity of historical and logical, analysis and synthesis, induction and deduction, comparison and analogy) and special methods of cognition (monetary methods). We employ the systems and integrated approach. The official statistics, regulations, works of leading researchers on shadow economy expansion, resources of reference and legal systems like Garant and ConsultantPlus serve as the study's information base. Results. We present a retrospective rapid analysis of the extent of shadow economic activity in the domestic economy, establishing the relationships with the processes that take place at different stages of the country's development. We also reveal the specifics of shadow economy relations in Russia, factors that play a key role in expansion for a particular period, a shift to another form of shadow economy. The study characterizes the current period of development, assesses the impact of external shocks on shadow economy expansion. Conclusions. The current period is characterized by the digitization of shadow relations, the shift of corruption to the upper echelons of power, the continued outflow of capital abroad, and increased penalties for underground activities.

scholarly journals Identifying loci under selection via explicit demographic models

2021 ◽  
Author(s):  
Hirzi Luqman ◽  
Alex Widmer ◽  
Simone Fior ◽  
Daniel Wegmann
Keyword(s):  
Demographic Models

scholarly journals Demographic effects of interacting species: exploring stable coexistence under increased climatic variability in a semiarid shrub community

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana I. García-Cervigón ◽  
Pedro F. Quintana-Ascencio ◽  
Adrián Escudero ◽  
Merari E. Ferrer-Cervantes ◽  
Ana M. Sánchez ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Species Coexistence ◽  
Climatic Factors ◽  
Demographic Data ◽  
Climatic Variability ◽  
Biotic Interactions ◽  
Vital Rates ◽  
Climatic Fluctuations ◽  
Demographic Models ◽  
Shrub Community

AbstractPopulation persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.

scholarly journals A Genealogical Interpretation of Linkage Disequilibrium

Genetics ◽  
2002 ◽  
Vol 162 (2) ◽  
pp. 987-991 ◽  
Author(s):  
Gilean A T McVean
Keyword(s):  
Monte Carlo Simulation ◽  
Population Structure ◽  
Linkage Disequilibrium ◽  
Population Bottlenecks ◽  
Neutral Model ◽  
Demographic Models ◽  
Degree Of Association ◽  
Different Parts ◽  
Direct Correspondence ◽  
Coalescence Times

Abstract The degree of association between alleles at different loci, or linkage disequilibrium, is widely used to infer details of evolutionary processes. Here I explore how associations between alleles relate to properties of the underlying genealogy of sequences. Under the neutral, infinite-sites assumption I show that there is a direct correspondence between the covariance in coalescence times at different parts of the genome and the degree of linkage disequilibrium. These covariances can be calculated exactly under the standard neutral model and by Monte Carlo simulation under different demographic models. I show that the effects of population growth, population bottlenecks, and population structure on linkage disequilibrium can be described through their effects on the covariance in coalescence times.

scholarly journals The Probability of Fixation in Populations of Changing Size

Genetics ◽  
1997 ◽  
Vol 146 (2) ◽  
pp. 723-733 ◽  
Author(s):  
Sarah P Otto ◽  
Michael C Whitlock
Keyword(s):  
Diffusion Equation ◽  
Adaptive Evolution ◽  
Process Model ◽  
Branching Process ◽  
Approximate Solutions ◽  
Logistic Growth ◽  
Beneficial Mutations ◽  
Demographic Models ◽  
Deleterious Alleles ◽  
Probability Of Fixation

The rate of adaptive evolution of a population ultimately depends on the rate of incorporation of beneficial mutations. Even beneficial mutations may, however, be lost from a population since mutant individuals may, by chance, fail to reproduce. In this paper, we calculate the probability of fixation of beneficial mutations that occur in populations of changing size. We examine a number of demographic models, including a population whose size changes once, a population experiencing exponential growth or decline, one that is experiencing logistic growth or decline, and a population that fluctuates in size. The results are based on a branching process model but are shown to be approximate solutions to the diffusion equation describing changes in the probability of fixation over time. Using the diffusion equation, the probability of fixation of deleterious alleles can also be determined for populations that are changing in size. The results developed in this paper can be used to estimate the fixation flux, defined as the rate at which beneficial alleles fix within a population. The fixation flux measures the rate of adaptive evolution of a population and, as we shall see, depends strongly on changes that occur in population size.

scholarly journals Reproductive failure in mice lacking inter-alpha-trypsin inhibitor (ITI) – ITI target genes in mouse ovary identified by microarray analysis

2004 ◽  
Vol 183 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Mika Suzuki ◽  
Hiroshi Kobayashi ◽  
Yoshiko Tanaka ◽  
Naohiro Kanayama ◽  
Toshihiko Terao
Keyword(s):  
Real Time ◽  
Trypsin Inhibitor ◽  
Target Genes ◽  
Reproductive Function ◽  
Pcr Analysis ◽  
Rt Pcr ◽  
Reproductive Process ◽  
Female Mice ◽  
Retinoid Metabolism ◽  
Regulatory Effects

Bikunin, a Kunitz-type protease inhibitor, is found in blood and urine. It has been established by two laboratories independently that the bikunin knockout female mice display a severe reduction in fertility: the cumulus oophorus has a defect in forming the extracellular hyaluronan-rich matrix during expansion. Proteins of the inter-alpha-trypsin inhibitor (ITI) family are eliminated in mice in which the bikunin gene has been inactivated, since bikunin is essential for their biosynthesis. Proteins of the ITI family may contribute to the microenvironment in which ovulation takes place. It is not clear, however, whether a single mechanism affects the reproductive function including ovulation. For identifying the full repertoire of the ITI deficiency-related genes, a cDNA microarray hybridization screening was conducted using mRNA from ovaries of wild-type or bik−/− female mice. A number of genes were identified and their regulation was confirmed by real-time RT-PCR analysis. Our screen identified that 29 (0.7%) and 5 genes (0.1%) of the genes assayed were, respectively, up- and down-regulated twofold or more. The identified genes can be classified into distinct subsets. These include stress-related, apoptosis-related, proteases, signaling molecules, aging-related, cytokines, hyaluronan metabolism and signaling, reactive oxygen species-related, and retinoid metabolism, which have previously been implicated in enhancing follicle development and/or ovulation. Real-time RT-PCR analysis confirmed that these genes were up- and down-regulated two- to tenfold by bikunin knockout. These studies demonstrate that proteins of the ITI family may exert potent regulatory effects on a major physiological reproductive process, ovulation.

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