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241.
Getting is Giving: Time Banking as Formalized Generalized Exchange   总被引:1,自引:0,他引:1       下载免费PDF全文
This article applies principles of the social exchange framework of social psychology to the social phenomenon of time banking. A “time bank” is an organization that facilitates the giving and receiving of services among its members by allowing them to provide a service, such as an hour of tutoring, in exchange for a “time credit,” which can then be redeemed for receipt of a service, such as an hour of yard work. Empirical research on time banking has focused on its ability to build community and its place within the sharing economy as a form of “connected consumption.” We build on these lines of thought by examining the practice of time banking as a formalized version of generalized exchange. Generalized exchange is a prosocial type of social exchange in which benefits are repaid indirectly, sometimes referred to as “paying it forward.” We discuss how two of time banking's most commonly cited benefits, building social capital and empowering members, can be better understood through this lens of generalized exchange. We then identify two specific motivational issues that time banks face and use a social exchange perspective to propose a possible solution under a framework we refer to as getting is giving.  相似文献   
242.
The prequential approach to statistics leads naturally to model list selection because the sequential reformulation of the problem is a guided search over model lists drawn from a model space. That is, continually updating the action space of a decision problem to achieve optimal prediction forces the collection of models under consideration to grow neither too fast nor too slow to avoid excess variance and excess bias, respectively. At the same time, the goal of good predictive performance forces the search over good predictors formed from a model list to close in on the data generator. Taken together, prequential model list re-selection favors model lists which provide an effective approximation to the data generator but do so by making the approximation match the unknown function on important regions as determined by empirical bias and variance.  相似文献   
243.
The dose–response relationship between folate levels and cognitive impairment among individuals with vitamin B12 deficiency is an essential component of a risk-benefit analysis approach to regulatory and policy recommendations regarding folic acid fortification. Epidemiological studies provide data that are potentially useful for addressing this research question, but the lack of analysis and reporting of data in a manner suitable for dose–response purposes hinders the application of the traditional evidence synthesis process. This study aimed to estimate a quantitative dose–response relationship between folate exposure and the risk of cognitive impairment among older adults with vitamin B12 deficiency using “probabilistic meta-analysis,” a novel approach for synthesizing data from observational studies. Second-order multistage regression was identified as the best-fit model for the association between the probability of cognitive impairment and serum folate levels based on data generated by randomly sampling probabilistic distributions with parameters estimated based on summarized information reported in relevant publications. The findings indicate a “J-shape” effect of serum folate levels on the occurrence of cognitive impairment. In particular, an excessive level of folate exposure is predicted to be associated with a higher risk of cognitive impairment, albeit with greater uncertainty than the association between low folate exposure and cognitive impairment. This study directly contributes to the development of a practical solution to synthesize observational evidence for dose–response assessment purposes, which will help strengthen future nutritional risk assessments for the purpose of informing decisions on nutrient fortification in food.  相似文献   
244.
We apply some log-linear modelling methods, which have been proposed for treating non-ignorable non-response, to some data on voting intention from the British General Election Survey. We find that, although some non-ignorable non-response models fit the data very well, they may generate implausible point estimates and predictions. Some explanation is provided for the extreme behaviour of the maximum likelihood estimates for the most parsimonious model. We conclude that point estimates for such models must be treated with great caution. To allow for the uncertainty about the non-response mechanism we explore the use of profile likelihood inference and find the likelihood surfaces to be very flat and the interval estimates to be very wide. To reduce the width of these intervals we propose constraining confidence regions to values where the parameters governing the non-response mechanism are plausible and study the effect of such constraints on inference. We find that the widths of these intervals are reduced but remain wide.  相似文献   
245.
ABSTRACT

Ferguson, Missouri became the center of the nation’s attention when an unarmed African American teenager was killed by a Caucasian police officer. Civic unrest continued for weeks. The aim of this study was to learn how older adults experienced the social unrest. Ten focus groups were conducted with 73 participants. Eight themes were identified. Issues related to safety were most commonly discussed. Participants reported a breakdown in intergenerational communications and expressed a desire for more exchange. Findings are being discussed with relevant organizations to increase the involvement of older adults in on-going community development efforts and to provide opportunities for intergenerational dialogue.  相似文献   
246.
Adolescent violence and abuse towards parents is under researched, especially in the UK where reports of the phenomenon are increasing with little clear guidance as to how practitioners might respond. In this qualitative study, 6 parents were recruited through youth offending teams and were interviewed about their lived experiences of violence and/or abuse from their adolescent child. Using interpretative phenomenological analysis, 3 superordinate themes emerged (a) the tensions and (b) the ambiguities produced by living with the violence and abuse and (c) the ways that parents manage the harms caused by these tensions and ambiguities. Theoretical and clinical implications are discussed, including consideration of how practitioners might support parents who are living with adolescent‐to‐parent violence and abuse to establish healthy and sustainable coping strategies while repairing family relationships.  相似文献   
247.
Partnerships and parenthood can have important effects on economic, social and psychological well-being. We provide new long-term analysis of how disability affects both parental status and partnerships. Analysis of the new Life Opportunities Survey, which is based on social model approaches, demonstrates that disabled people are more likely than non-disabled people to face disadvantages in terms of family formation. Disabled people are more likely to remain single over time, although there is less evidence for any differences in rates of relationship breakdown for those who enter them. Allied to these conclusions, disabled adults are less likely to form households where there are dependent children. These conclusions are supported by longitudinal results from the British Household Panel Survey.  相似文献   
248.
249.
Although gross primary productivity (GPP) is estimated with remote sensing over large regions of Earth, urban areas are usually excluded due to the lack of light use efficiency (LUE) parameters for urban vegetation and the spatial heterogeneity of urban land cover. Here, we estimated midsummer GPP, both within and among vegetation and land-use types, across the Minneapolis-Saint Paul, Minnesota metropolitan region. We derived LUE parameters for urban vegetation types using estimates of GPP from tree sap flow and eddy covariance CO2 flux observations, and from fraction of absorbed photosynthetically active radiation based on 2 m resolution WorldView-2 satellite imagery. Mean GPP per unit land area (including vegetation, impervious surfaces, and soil) was 2.64 g C m?2 d?1, and was 4.45 g C m?2 d?1 per unit vegetated area. Mapped GPP estimates were within 11.4% of estimates from independent tall tower eddy covariance measurements. Turf grass GPP had a larger coefficient of variation (0.18) than other vegetation classes (~0.10). Vegetation composition was largely consistent across the study area. Excluding golf courses, mean land-use GPP for the total study area varied more by percent vegetation cover (R2?=?0.98, p?<?0.001) than by variability within vegetation classes (R2?=?0.21, p?=?0.19). Urban GPP in general was less than half that of natural forests and grasslands in the same climate zone.  相似文献   
250.
ABSTRACT

Through empirical research on academics and veterinary surgeons, this article focuses on identity and how it is reflected in, and reproduced by, anxiety and insecurity at work. Three analytical themes – perfection, performativity and commodified service – each of which generates anxiety indicates a loss of autonomy as academics and vets are subjected to competitive market forces as well as an intensification of masculine managerial controls of assessment, audit and accountability. We see these pressures and their effects as reflecting a commodification of service provision where the consumer (student or client) begins to redefine the relationship between those offering some expertise and those who are its recipients, partly achieved through the performative gaze of constant and visible rating mechanisms. Our empirical research also identifies sources of anxiety concerns in their attempts to achieve perfection against this background of uncertain knowledge and precarious contexts of the performative nature of professional expertise.  相似文献   
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