Sökning: "population structure"

Visar resultat 36 - 40 av 734 avhandlingar innehållade orden population structure.

1. 36. Population genetic analyses in the orchid genus Gymnadenia : a conservation genetic perspective

   Författare :Susanne Gustafsson; Pia Mutikainen; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Genetic engineering; Orchidaceae; Gymnadenia; conservation; microsatellites; genetic structure; mating pattern; Genteknik; Genetic engineering including functional genomics; Genteknik inkl. funktionsgenomik; naturvårdsbiologi; Conservation Biology;

   Sammanfattning : Small populations are facing a particular risk of extinction due to a lack of appropriate genetic diversity and associated negative effects, factors dealt with in the discipline of conservation genetics. Many orchid species exhibit characteristics that make them a perfect study object in the scope of conservation genetics. LÄS MER

3. 37. POPULATION DYNAMICS AND TREE GROWTH STRUCTURE IN MATHEMATICAL ECOLOGY

   Författare :Tin Nwe Aye; Linus Carlsson; Sergei Silvestrov; Masood Ayapoor; Christian Engström; Mälardalens högskola; []
   Nyckelord :Mathematics Applied Mathematics; matematik tillämpad matematik;

   Sammanfattning : This thesis is based on four papers related to mathematical biology, where three papers focus on population dynamics and one paper concerns tree growth and stem structure. The first two papers are mainly devoted to studying the dynamics of physiologically structured population models by using Escalator Boxcar Train (EBT) method. LÄS MER

4. 38. Live Longer, Work Longer? Evidence from Sweden’s Ageing Population

   Författare :Haodong Qi; Centrum för ekonomisk demografi; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Employment; Retirement Behavior; Working Life; Labor Supply; Pension Reform; Financial Incentives; Population Ageing;

   Sammanfattning : Sweden’s elderly population is growing, propelled by a continuous decline in old-age mortality, while coupled with a persistent replacement level fertility. This changing age structure increases the per worker cost of providing a given age-vector of per capita benefits, encompassing costs for pensions, health care, and all other type of old-age welfare services, which presents a looming challenge for the welfare state to sustain its social transfer system. LÄS MER

5. 39. Population differentiation in Lythrum salicaria along a latitudinal gradient

   Författare :Katarina Olsson; Jon Ågren; Susan Kalisz; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; additive genetic variance; clinal variation; evolutionary constraints; G matrix; genetic correlation; natural selection; pollen limitation; population differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. LÄS MER

7. 40. Life histories and population dynamics

   Författare :Annie Jonsson; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : During the last decades there has been a growing interest and attention to random variation in population densities and their causes. It has been shown that even in constant environments (deterministic population growth) the dynamics of populations can display random like behaviour depending on parameter values. LÄS MER