Individual-level Effects (individual-level + effects)

Distribution by Scientific Domains


Selected Abstracts


Why do citizens want to keep refugees out?

EUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 1 2007
Threats, fairness, hostile norms in the treatment of asylum seekers
A social identity framework was employed to understand why people support the exclusionary treatment of refugee claimants (,asylum seekers') in Australia. Over and above individual difference effects of social dominance orientation and individuals' instrumental threat perceptions, insecure intergroup relations between citizens and asylum seekers were proposed to motivate exclusionary attitudes and behaviour. In addition, perceived procedural and distributive fairness were proposed to mediate the effects of social identity predictors on intergroup competitiveness, serving to legitimise citizens' exclusionary behaviours. Support for these propositions was obtained in a longitudinal study of Australians' social attitudes and behaviour. Small and inconsistent individual-level effects were noted. In contrast, after controlling for these variables, hostile Australian norms, perceived legitimacy of citizen status, and threatening socio-structural relations were strongly and consistently linked to intentions to support the harsh treatment of asylum seekers, and exclusionary attitudes and action at Time 2. Moreover, perceived procedural and distributive justice significantly mediated these relationships. The roles of fairness and intergroup socio-structural perceptions in social attitudes and actions are discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source]


The Effects of Health Sector Market Factors and Vulnerable Group Membership on Access to Alcohol, Drug, and Mental Health Care

HEALTH SERVICES RESEARCH, Issue 3p1 2007
Susan E. Stockdale
Objective. This study adapts Andersen's Behavioral Model to determine if health sector market conditions affect vulnerable subgroups' use of alcohol, drug, and mental health services (ADM) differently than the general population, focusing specifically on community-level predisposing and enabling characteristics. Data Sources. Wave 2 data (2000,2001) from the Health Care for Communities study, supplemented with cases from wave 1 (1997,1998), were merged with area characteristics taken from Census, Area Resource File (ARF), and other data sources. Study Design. The study used four-level hierarchical logistic regression to examine access to ADM care from any provider and specialty ADM access. Interactions between community-level predisposing and enabling vulnerability characteristics with individual race/ethnicity, age, income category, and insurance type were explored. Principal Findings. Nonwhites, the poor, uninsured, and elderly had lower likelihoods of service use, but interactions between race/ethnicity, income, age and insurance status with community-level vulnerability factors were not statistically significant for any service use. For ADM specialty care, those with Medicare, Medicaid, private fully managed, and private partially managed insurance, the likelihood of utilization was higher in areas with higher HMO penetration. However, for those with other insurance or no insurance plan, the likelihood of utilization was lower in areas with higher HMO penetration. Conclusions. Community-level enabling factors explain part of the effect of disadvantaged status but, with the exception of the effect of HMO penetration on the relationship between insurance and specialty care use, do not modify any of the residual individual-level effects of disadvantage. Interventions targeting both structural and individual levels may be necessary to address the problem of health disparities. More research with longitudinal data is necessary to sort out the causal direction of social context and ADM access outcomes, and whether policy interventions to change health sector market conditions can shift ADM treatment utilization. [source]


Selection on Arctic charr generated by competition from brown trout

OIKOS, Issue 3 2003
Torbjørn Forseth
We experimentally explored population- and individual-level effects on Arctic charr (Salvelinus alpinus) resulting from resource competition with its common European competitor, the brown trout (Salmo trutta). At the population level, we compared performance of the two species in their natural sympatric state with that of Arctic charr in allopatry. At the individual level, we established selection gradients for morphological traits of Arctic charr in allopatric and in sympatric conditions. We found evidence for interspecific competition likely by interference at the population level when comparing differences in average performance between treatments. The growth and feeding rates did not differ significantly between allopatric and sympatric Arctic charr despite lower charr densities (substitutive design) in sympatric enclosures indicating that inter- and intraspecific competition are of similar strength. The two species showed distinct niche segregation in sympatry, and brown trout grew faster than Arctic charr. Arctic charr did not expand their niche in allopatry, indicating that the two species compete to a limited degree for the same resources and that interference may suppress the growth of charr in sympatric enclosures. At the individual level, however, we found directional selection in sympatric enclosures against individual Arctic charr with large head and long fins and against individuals feeding on zoobenthos rather than zooplankton indicating competition for common resources (possibly exploitative) between trout and these charr individuals. In allopatric enclosures these relations were not significant. Diets were correlated to the morphology supporting selection against the benthic-feeding type, i.e. individuals with morphology and feeding behaviour most similar to their competitor, the benthic feeding brown trout. Thus, this study lends support to the hypothesis that Arctic charr have evolved in competition with brown trout, and through ecological character displacement adapted to their present niche. [source]


Modelling impacts of long-line fishing: what are the effects of pair-bond disruption and sex-biased mortality on albatross fecundity?

ANIMAL CONSERVATION, Issue 4 2005
Michael S. L. Mills
Long-line fishing mortality poses a significant threat to many large procellariiform seabirds. To date, estimates of impacts have concentrated on lower survival rates, largely ignoring the costs to fecundity resulting from disruption of breeding pairs and skews in sex ratio. A comparative, stochastic, individual-based model was used to investigate these costs for the wandering albatross Diomedea exulans. Ignoring the time taken to replace a lost mate overestimates fecundity by 13,18%, resulting in annual population growth rates (,) being 0.006,0.007 too high. Long-line mortality exacerbates this cost, which becomes more substantial with increasing demographic skew resulting from female-biased mortality. At moderate levels of long-line mortality (2,4% per year), 80% female-biased mortality reduces fecundity by 9,27% and , by 0.003,0.010 relative to models with random mortality. Biased sex ratios accumulate and, unlike reduced survival, their impacts on albatross demography persist after long-line mortality ceases. Estimates of the demographic costs of long-line mortality should incorporate individual-level effects, especially where mortality is sex-biased. [source]