Three main hypotheses have been postulated over the past century to explain the outbreaking population dynamics of eastern spruce budworm, Choristoneura fumiferana (Clemens). The Silviculture Hypothesis first arose in the 1920s, with the idea that outbreaks were driven by forestry practices favoring susceptible softwood species. In the 1960s, it was proposed that populations were governed by Mu...

Genetic diversity is essential for population survival and adaptation to changing environments. Demographic processes (e.g., bottleneck and expansion) and spatial structure (e.g., migration, number, and size of populations) are known to shape the patterns of the genetic diversity of populations. However, the impact of temporal changes in migration on genetic diversity has seldom been considered...

in this paper, the factors affecting the attitude of youth toward immigration have been examined, using a survey method and questionnaire. the sample under study consisted of 892 young people from shiraz. the theoretical framework of the research was based on the theories of giddens, bayen, izen, and lee’s theory of immigration and the experimental method of research was designed based on their...

We investigate the effect of immigration on the labor supply of skilled women, using data on Spain’s large recent immigration wave. We adopt a spatial correlations approach and instrument for current immigration using ethnic networks. We find that female immigration increases the local availability of household services and reduces their price. It also increases the labor supply of skilled nati...

Researchers have suggested that perceptions of discrimination may vary depending on place of birth and the length of time spent living in the U.S., variables related to acculturation. However, the existing literature provides a mixed picture, with data suggesting that the effects of acculturation on perceptions of discrimination vary by race and other sociodemographic factors. This study evalua...

This study examined the relationships among cognitive variables, family immigration history, negative life events, and depressive symptoms in a sample of 306 low-income, urban fifth- and sixth-grade children. Explanatory style and negative automatic thoughts were the cognitive variables examined. There were three key findings. First, children who were immigrants reported significantly more depr...

Migratory birds often follow detours when confronted with ecological barriers, and understanding the extent and the underlying drivers of such detours can provide important insights into the associated cost to the annual energy budget and the migration strategies. The Qinghai-Tibetan Plateau is the most daunting geographical barrier for migratory birds because the partial pressure of oxygen is ...

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...

It seems like a day does not go by in the United States without hearing about immigration on televised news broadcasts, print news stories, radio talk shows, or Internet blogs. Immigration, more specifically “illegal immigration,” is a hot topic in the U.S., perhaps fueled by the fact that 2008 is a presidential election year. Furthermore, since the issue of illegal immigration tends to divide ...