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981.
Pollen specialization by solitary bees in an urban landscape 总被引:1,自引:1,他引:0
Many polylectic bee species are known to specialize locally on one or a few pollen types to increase foraging efficiency. What is relatively unknown is how different landscapes influence foraging decisions, and whether habitat alteration, such as that resulting from urbanization, influences broad-scale foraging activities of bees. This study evaluates the type and diversity of pollen collected by two solitary bees that are common in Toronto, Ontario, Canada, the native Osmia pumila and the exotic O. caerulescens, sampled in trap nests set up in urban parks and gardens. We found that the dominant pollen in every successful brood cell was either of one widespread, cosmopolitan lawn-invasive plant species (Trifolium repens) or one of two wind-pollinated tree genera (Quercus spp. and Betula spp.). In combination, these three represented more than 90 % of all pollen collected by each bee species. Despite considerable overlap in the dominant pollen types collected by each bee species, the exotic O. caerulescens was significantly more specialized than the native O. pumila. Brood cells with Betula as the dominant pollen type were more pollen species-rich than those cells having Trifolium or Quercus as dominant, perhaps a result of the comparatively low protein content in Betula pollen. 相似文献
982.
Global guidelines for physical activity are not being met by most of the world’s youths, adults, and older adults. Family and friends who engage in physical activity across generations derive emotional, social, cognitive, and physical benefits from their interaction. Youths depend on adult assistance to travel long distances, adults are encumbered with obligations to work, and older adults often live more than 200 miles from their extended families. Intergenerational physical activity is difficult because generations are distant and lead busy lifestyles. Remotely played exergames can connect family and friends for intergenerational physical activity. Internet exergaming can help to make physical activity convenient and enjoyable as well as eliminate the effect of distance on playing with family and friends. 相似文献
983.
Researchers have documented the consequences of relationship instability for parenting stress but have given little attention to within‐partner relationship instability. In this study, the authors used data from the Fragile Families and Child Wellbeing Study (N = 3,544) to estimate the association between within‐partner relationship instability (known as churning or on‐again/off‐again relationships) and parenting stress. First, they found that by the focal child's 5th birthday about 16% of biological parents experience churning. Second, compared to being stably together with or stably separated from the child's other parent, churning is associated with greater parenting stress for both mothers and fathers. Because parenting stress is the same or higher among churners compared to their counterparts who stably separate, this suggests that, more than a change in partner, relationship instability—whether within or across relationships—is tied to parenting stress. 相似文献
984.
Rafaela Ganga José Pedro Silva Rui Gomes Henrique Vaz João Teixeira Lopes Sílvia Silva Luísa Cerdeira Belmiro Cabrito Dulce Magalhães Maria de Lurdes Machado‐Taylor Paulo Peixoto Tomás Patrocínio Rui Brites 《International migration (Geneva, Switzerland)》2016,54(6):43-55
In the economic and social aftermath of the 2008 crisis there has been an important and growing new wave of highly qualified Portuguese emigration comprising scientists. No or very few public policies have been designed to reverse this phenomenon, risking the consequences of brain drain. International literature argues that professional reasons are central to scientists’ decision to migrate, even after the 2008 crisis. Spending some time in a foreign country to study, research, or teach, is perceived as a common step in an individual academic trajectory and an advantage for a successful professional career in academia. It is also encouraged by European Union policies. Twelve individual portraits of Portuguese scientists living in central Europe reveal how important other factors are to the migration decision‐making process. These factors include the economic crisis, student mobility programmes, and the current Portuguese scientific system revision. 相似文献
985.
Liene Ozoliņa‐Fitzgerald 《The British journal of sociology》2016,67(3):456-475
This article presents an ethnographic study of politics of waiting in a post‐Soviet context. While activation has been explored in sociological and anthropological literature as a neo‐liberal governmental technology and its application in post‐socialist context has also been compellingly documented, waiting as a political artefact has only recently been receiving increased scholarly attention. Drawing on ethnographic fieldwork at a state‐run unemployment office in Riga, this article shows how, alongside activation, state welfare policies also produce passivity and waiting. Engaging with the small but developing field of sociological literature on the politics of waiting, I argue that, rather than interpreting it as a clash between ‘neo‐liberal’ and ‘Soviet’ regimes, we should understand the double‐move of activation and imposition of waiting as a key mechanism of neo‐liberal biopolitics. This article thus extends the existing theorizations of the temporal politics of neo‐liberalism. 相似文献
986.
987.
Unemployment,Reemployment, and Health Insurance Status Among Older Workers in the Flexible Labor Market 下载免费PDF全文
As employment becomes more precarious, and spells of displacement become more common across the labor market, many individuals are forced to make decisions about the speed at which they seek reemployment and the types of employment they will seek. Using repeated cross‐sectional data from various years of the Displaced Worker Supplement of the Current Population Survey, we examine the degree to which employer‐provided health insurance and organizational provision of advanced layoff warning helped workers—particularly those from earlier birth cohorts—navigate the labor market during a period of growing employment flexibility. Our results indicate that workers from older cohorts, rather than older chronological ages, suffered more from displacement in terms of longer unemployment spells and declines in job quality upon reemployment. Workers able to obtain a job with health insurance had shorter unemployment durations, while those displaced from jobs with health insurance remained unemployed for longer periods of time. Advance notice appears to reduce some of the disproportionately negative effects of displacement for older workers, perhaps by easing the shock of a psychological contract breach. Our findings point to the importance of historical and cultural factors in shaping labor market outcomes. 相似文献
988.
The Role of Household Social Organization in the Structure of Rural Economies: Comparing Forest Resource Dependent and Agriculturally Dependent Regions in Russia 下载免费PDF全文
Sociologists have examined how structural economic change affects household social organization and generation of household income from different sources. The introduction of elements of a market economy into rural Russia in the early 1990s provides a unique opportunity to examine these relationships. Much of the work on this topic, however, has been conducted in black earth zone, agriculturally dependent regions. Less attention has been given to non‐black‐earth zone, forest resource dependent regions. This article addresses this limitation by comparing the relationships between household income generation strategies and household social organization in a 2009 survey of villages in three forest resource dependent regions in northwest Russia with findings from a 2006 survey of households in nine agricultural regions of Russia. Income generated from enterprises based on household social organization—household labor and social helping networks—is substantially greater in agriculturally dependent than in forest resource dependent regions. We discuss the implications of these findings for understanding intranational regional differences in the relationship between economic systems, household social organization, and rural household economies as well as the obstacles facing policymakers and environmentalists who attempt to shift household income generation strategies away from an environmentally harmful lumber industry to income generation activities that are less harmful to the environment. 相似文献
989.
Residential Instability,Family Support,and Parent–Child Relationships Among Ethnically Diverse Urban Families 下载免费PDF全文
From a social disorganization standpoint, neighborhood residential instability potentially brings negative consequences to parent–child relationship qualities, but family social support and racial/ethnic identity may modify this association. Using data (n = 3,116) from the Project on Human Development in Chicago Neighborhoods, this study examines associations between neighborhood residential instability and parent–child warmth and conflict, whether family social support moderates associations between residential instability and parent–child relationships, and variation by race/ethnicity. Multilevel models reveal that residential instability undermines parent–child relationship qualities, particularly for non‐White individuals. Family support is a protective factor for families in less stable neighborhoods and specifically buffers the association between neighborhood residential instability and reduced parent–child warmth. Among Hispanics, family support mitigates the association between residential instability and heightened parent–child conflict. Findings highlight residential instability as a detriment to parent–child relationships; families in unstable neighborhoods may benefit from family social support. 相似文献
990.
A Cost–Benefit Analysis of a Family Systems Intervention for Managing Pediatric Chronic Illness 下载免费PDF全文
Brian J. Distelberg Natacha D. Emerson Paul Gavaza Daniel Tapanes Whitney N. Brown Huma Shah Jacqueline Williams‐Reade Susanne Montgomery 《Journal of marital and family therapy》2016,42(3):371-382
Despite recent increases of psychosocial programs for pediatric chronic illness, few studies have explored their economic benefits. This study investigated the costs–benefits of a family systems‐based, psychosocial intervention for pediatric chronic illness (MEND: Mastering Each New Direction). A quasi‐prospective study compared the 12‐month pre–post direct and indirect costs of 20 families. The total cost for program was estimated to $5,320. Families incurred $15,249 less in direct and $15,627 less in indirect costs after MEND. On average, medical expenses reduced by 86% in direct and indirect costs, for a cost–benefit ratio of 0.17. Therefore, for every dollar spent on the program, families and their third payers saved approximately $5.74. Implications for healthcare policy and reimbursements are discussed. 相似文献