939 resultados para 1603 Demography
Resumo:
Ocean acidification is predicted to have detrimental effects on many marine organisms and ecological processes. Despite growing evidence for direct impacts on specific species, few studies have simultaneously considered the effects of ocean acidification on individuals (e.g. consequences for energy budgets and resource partitioning) and population level demographic processes. Here we show that ocean acidification increases energetic demands on gastropods resulting in altered energy allocation, i.e. reduced shell size but increased body mass. When scaled up to the population level, long-term exposure to ocean acidification altered population demography, with evidence of a reduction in the proportion of females in the population and genetic signatures of increased variance in reproductive success among individuals. Such increased variance enhances levels of short-term genetic drift which is predicted to inhibit adaptation. Our study indicates that even against a background of high gene flow, ocean acidification is driving individual- and population-level changes that will impact eco-evolutionary trajectories.
Resumo:
In a traditional system of exogamous and patrilocal marriage prevalent in much of Sub-Saharan Africa, when she marries, a rural woman typically leaves her kin to reside with her husband living outside her natal village. Since a village that allows a widow to inherit her late husband's land can provide her with old age security, single females living outside the village are more likely to marry into the village. Using a natural experimental setting, provided by the longitudinal household panel data drawn from rural Tanzania for the period from 1991 to 2004, during which several villages that initially banned a widow's land inheritance removed this discrimination, this study provides evidence in support of this view, whereby altering a customary land inheritance rules in a village in favor of widows increased the probability of males marrying in that village. This finding suggests that providing rural women with old age protection (e.g., insurance, livelihood protection) has remarkable spatial and temporal welfare effects by influencing their decision to marry.
Resumo:
This short essay, built on a foundation of more than a decade of fieldwork in the hydrocarbon-rich societies of the Arabian peninsula, distills a set of overarching threads woven through much of that time and work. Those threads include a discussion of the social heterogeneity of the Gulf State citizenries, the central role of development and urban development in these emergent economies, the multifaceted impact of migrants and migration upon these host societies, and the role of foreign 'imagineers' in the portrayal of Gulf societies, Gulf values, and Gulf social norms.
Resumo:
Port. con escudo xil. real de Felipe II
Resumo:
Port. con escudo xil. real de Felipe II