نتایج جستجو برای: depended to immigration
تعداد نتایج: 10618431 فیلتر نتایج به سال:
Climate-induced phenological shifts can influence population, evolutionary, and ecological dynamics, but our understanding of these phenomena is hampered by a lack of long-term demographic data. We use a multi-decade census of 5 salmonid species representing 14 life histories in a warming Alaskan stream to address the following key questions about climate change and phenology: How consistent ar...
Americans' conflicted attitudes toward immigrants and immigration has stymied immigration reform for decades. In this article, we explore the nuanced nature of stereotypes about immigrants and how they relate to ambivalent attitudes toward immigrant groups and the disparate array of immigration policies that affect them. Using item response theory and multiple regression analysis, we identified...
BACKGROUND Migrant populations consist of migrants with differences in generational status and length of residence. Several studies suggest that health outcomes differ by generational status and duration of residence. We examined the association of generational status and age at immigration of the mother with infant mortality in migrant populations in The Netherlands. METHODS Data from Statis...
Immigration, Citizenship, and the Size of Government This paper analyzes the political sustainability of the welfare state in an environment where immigration is the main demographic force and where governments are able to influence the size and skill composition of immigration flows. Specifically, I present a dynamic politicaleconomy model where both income redistribution and immigration polic...
We tested the hypothesis that temporally autocorrelated variation should increase the abundance of an inferior competitor sustained by immigration. Temporally autocorrelated variability can increase abundance of the inferior species through effects on demography, the strength of competition, and the mean and variance in the abundance of competing species. We allowed the competitive inferior to ...
Theoretical studies of adaptation to sink environments (with conditions outside the niche requirements of a species) have shown that immigration from source habitats can either facilitate or inhibit local adaptation. Here, we examine the influence of immigration on the evolution of local adaptation, given an Allee effect (i.e., at low densities, absolute fitness increases with population densit...
This paper presents a case study of migrant transnationalism on the basis of ethnographic data collected among Croatians migrants in Western Australia. So far transnationalism has been theorized as the sustained connection of migrants to their homelands, while this paper introduces a distinction between “ethnic” and “cosmopolitan” transnationalism. The sample of respondents comes from two disti...
The understanding of migration patterns can significantly contribute to conservation and management. The spawning migrations of Atlantic salmon (Salmo salar) cover thousands of kilometers from the feeding areas at sea to their natal rivers to reproduce. Migrating salmon are exposed to intensive harvest, but little is known of the population-specific differences in migration behavior. In this st...
Flight direction is a major component of an animal's migratory success. However, few studies have focused on variation in flight direction both between and within individuals, which is likely to be correlated with other traits implied in migration processes. We report patterns of intra- and inter-individual variation in flight direction in the large white butterfly Pieris brassicae. The presenc...
OBJECTIVE To investigate the altitude, immigration and suicide rates association in Turkey. METHODS Suicide and immigration rates of 81 provinces and their elevation data were obtained. RESULTS There were not significant correlations between country elevation, immigration and mean suicide rate. CONCLUSION The findings of this study points out that altitude related hypoxia and suicide asso...
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