Connectivity in urbanizing landscapes: The importance of habitat configuration,urban area size,and dispersal

Human activities affect both the amount and configuration of habitat. These changes have important ecological implications that can be measured as changes in landscape connectivity. I investigated how urbanization interacts with the initial amount and aggregation of habitat to change dispersal potential, restoration potential, and the risk of spatially extensive disturbances. I used a factorial set of simulated landscapes and subjected each landscape to habitat loss by overlaying 66 different US urban areas. I used a common connectivity metric, CONNECT, to assess the magnitude and direction of changes for a range of dispersal distances. My results show that the relationship between habitat loss and connectivity loss is non-linear and subject to interactions between the spatial patterns of habitat distribution, urban morphology, and dispersal capabilities. The implications of a given urban form vary widely as a function of habitat distribution and dispersal capabilities. This implies that impact assessments, restoration activities, and conservation planning should consider historical habitat distribution when evaluating observed changes in connectivity. While my results clearly show that more aggregated or continuous habitats are more vulnerable to connectivity loss, this approach can also be used to identify landscapes where restoring connectivity will be particularly effective, for example through placement of stepping stone habitats.     

Differences in Delaying Motherhood Across European Countries: Empirical Evidence from the ECHP

Motherhood postponement and fertility decline have been observed in almost all developed countries. In this article, we aim to assess some of the potential determinants of first childbirth timing in Europe, in a comparative perspective, using data from the European Community Household Panel Survey (ECHP). We estimate, separately by country, hazard rates for the timing at first childbirth conditioning to education and work characteristics. Moreover, in order to explain differences between European countries, we decompose the differences between rates in the part due to the national population composition by specific characteristics and the part due to different propensities for women with given characteristics.     

Does Family Structure Matter in the Relationships Between Youth Assets and Youth Alcohol,Drug and Tobacco Use?

This study investigated significant relationships between youth assets and youth alcohol, tobacco, and drug use that differ according to family structure (one- or two-parent households). Data were collected from a randomly sampled inner-city population (n=1,256 teenagers and 1,256 parents of the teenagers) using in-home, in-person interviews. Logistic regression analyses, stratifying by one- and two-parent household status, were conducted with nine youth assets as the independent variables and youth alcohol, tobacco, and drug use as the dependent variables. Results indicated that the associations between assets and risk behaviors varied depending upon whether the youth lived in one- or two-parent households. Continued research is warranted to further investigate associations among family structure, youth assets, and youth risk behaviors.     

Contexte local et migration: l’exemple des dynamiques migratoires internationales de quartiers dans la ville sénégalaise de Kaolack

Despite the diversity of the variables considered, explanatory models of migration do not fully incorporate the locality of origin as a scale of observation for migratory behaviour. Migration is often perceived to generate notions of territory; conversely, are local territories drivers of mobility? If so, in what forms, and by what means? This article analyses international migration from the city of Kaolack in Senegal, with particular focus on the role of the neighbourhood in migration dynamics. Here, the neighbourhood is seen as relatively homogeneous and singular historical and social entity. The ties that are established and maintained from one generation to the next take the form of shared lifestyles and modes of organization which may influence inhabitants’ propensity to emigrate.     

Grandchild Care Transfers by Ageing Immigrants in France: Intra-household Allocation and Labour Market Implications

Using a unique sample on ageing first generation immigrants in France, we explore the distribution of grandchild care across offspring and the impact of this transfer on the labour supply of the mother. Our results indicate that grandchild care is spread unequally across siblings, and this inequality is driven more strongly by better labour market potential than by weaker financial status of the recipient. There is further evidence that even after accounting for potential endogeneity and unobserved heterogeneity, grandchild care has a positive impact on the labour supply of the mother. The pattern of intergenerational time transfers differs across people with different national and religions backgrounds.     

Race–gender Differences in Risk and Protective Factors among Youth in Residential Group Homes

Analysis reported here examined youth in residential group home placements in order to better understand how sexual behaviors, drug use, and environmental experiences differ by race and gender subgroups. Data were collected from 336 youth aged 14–21 residing in one of 41 group homes in Maryland. Chi square and logistic regression analyses were done to determine differences on study variables among the race-gender groupings. Results demonstrate not only significant health concerns overall but notable differences were also found between race-gender subgroups. Findings suggest that found race-gender subgroup differences might be informative for tailoring programming for youth of residential group home settings.     

The Significance of Shift Work: Current Status and Future Directions

This paper provides a review and synthesis of research literature on the effects of shift work on workers’ physical health, mental health/well-being, and family life. The focus is on current knowledge, unanswered questions, and new directions for future research. The selection of research literature is guided by a general conceptual framework that identifies predictor variables, moderating variables, and outcome variables. The paper concludes with a discussion of the variables that should be incorporated into an agenda for future research.