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251.
Trees provide important ecological services in cities, yet the vulnerability of the urban forest to massive tree losses from pest outbreaks could threaten those services, with unknown environmental consequences. The outbreak of emerald ash borer is an imminent threat to the ash population in North America. In the Minneapolis?CSaint Paul, Minnesota, metropolitan area, ash trees are present in 50?% of residential landscapes in Ramsey and Anoka Counties. We used a large survey of household activities, a tree inventory, a Household Flux Calculator accounting tool, and a set of annual evapotranspiration measurements, to quantify the current carbon, nitrogen, and phosphorus storage in ash trees, the cycling of these elements, and the total evapotranspiration from ash trees in residential areas in the metropolitan region. Ash represented 6?% of the trees in residential areas and the removal of the entire ash population would correspondingly reduce net primary production and carbon sequestration by only a few percent and would have negligible effects on losses of nitrogen and phosphorus from residential landscapes. Similarly, the effects of ash loss on the hydrologic cycle would be minimal and would depend largely on management choices for the ground currently underneath ash tree canopies. Overall, the percentage change in biogeochemical and hydrological fluxes corresponded closely with the percent of the total urban tree population that was represented by ash, suggesting that areas with higher densities of ash would experience correspondingly larger effects. A hypothetical tree replacement scenario with similar broadleaf species was determined to be likely to re-establish the original biogeochemical and hydrological conditions once the replacement trees reach maturity.  相似文献   
252.
This study examined pathways to early coital debut among early to middle adolescent girls in the United States. In a two-year longitudinal study of 104 adolescent girls, recursive partitioning (RP) analyses were conducted to examine the specific factors that were related to engaging in first intercourse by the 10th grade among adolescent girls who had not yet engaged in sexual intercourse by the 8th grade. RP analyses identified subsamples of girls who had low, medium, and high likelihoods of engaging in early coital debut based on six variables (i.e., school aspirations, early physical intimacy experiences, depression, body objectification, body image, and relationship inauthenticity). For example, girls in the lowest likelihood group (3% had engaged in sex by the 10th grade) reported no prior experiences with being touched under their clothes, low body objectification, high aspirations to complete graduate education, and low depressive symptoms; girls in the highest likelihood group (75% had engaged in sex by the 10th grade) also reported no prior experiences with being touched under their clothes, but had high levels of body objectification. The implications of these analyses for the development of female adolescent sexuality, as well as for advances in quantitative methods, are discussed.  相似文献   
253.
In Egypt, kin relations have been governed by a patriarchal contract, which defines expectations for intergenerational support along gendered lines. Social changes may be disrupting these customs and bringing attention to the ways gender may influence intergenerational support in rapidly changing contexts. Using data from 4,465 parent–child dyads in Ismailia, Egypt, we examined whether intergenerational material transfers favored women over men and whether gaps in needs and endowments accounted for gender differences in transfers. Fathers gave children money and goods more often than did mothers; mothers received material transfers from children more often than did fathers. Compared to sons, daughters made transfers to parents less often and received transfers from parents more often. We found residual advantages to mothers and daughters, even adjusting for differential needs and endowments. Findings corroborate persistent norms of gender complementarity, patrilocal endogamy, and reciprocation for women's caregiving, despite changes that have threatened patriarchal rules of exchange.  相似文献   
254.
This paper examines the failed attempt to reauthorize the American educational law known as No Child Left Behind (NCLB) in 2007. Drawing on existing research on cultural processes of policymaking and insights from inhabited institutionalism, we analyze data from 20 congressional hearings, viewing them as social interactions. We find that hearing participants identified problems with strict accountability policies and, in interpreting those problems, introduced alternative meanings, including “NCLB means children left behind.” Our approach stresses the symbolic politics of reform at the meso level of interaction and makes the case for a cultural analysis of policymaking that synthesizes both interactionism and institutionalism.  相似文献   
255.
This study examines the use of Facebook by Lowe's to reach its stakeholders after the controversial decision to pull its advertising from TLC's All-American Muslim. Through an online survey, the study gauges people's thoughts about the use of Facebook to apologize. Results showed significant differences based on age, race/ethnicity, and political affiliation regarding the use of Facebook and significant differences based on education, time spent on Facebook, political affiliation and race/ethnicity regarding the wording of Lowe's apology.  相似文献   
256.
257.
Previous research suggests that the choice of graphical format for communicating risk information affects both understanding of the risk magnitude and the likelihood of acting to decrease risk. However, the mechanisms through which these effects work are poorly understood. To explore these mechanisms using a real‐world scenario, we examined the relative impact of two graphical displays for depicting the risk of exposure to unexploded ammunition during potential land redevelopment. One display depicted only the foreground information graphically (a bar graph of the number of people harmed), and a second depicted the foreground and background graphically (a stacked bar graph representing both the number harmed and at risk). We presented 296 participants with either the foreground‐only or the foreground and background graphical display and measured a broad set of outcome variables, examining (1) the graphical display effect on each of the outcome measures and (2) the pathways by which any display effects work to influence decision making. We found that the foreground‐only graphical display increased perceived likelihood and experienced fear, which produced greater worry, which in turn increased risk aversion. In addition, a positive evaluation of the communication materials increased support for policies related to land redevelopment, whether those policies were risk taking or risk mitigating. Finally, the foreground‐only graphical display decreased understanding of the risk magnitude, showing that approaches to accomplish one risk communication goal (promoting risk‐averse decisions) may do so at the expense of another goal (increasing understanding).  相似文献   
258.
In the aftermath of the Great Recession, a substantial number of families were left financially at risk, especially those with lower income, less wealth, fewer years of education, and unstable employment. This study examined how families responded to the financial stresses of the Great Recession and found that families who were working age, had higher levels of education, and had become non-homeowners were more likely to maintain or open a basic savings account; whereas families who had lost a substantial amount of annual family income or wealth or were Black or Hispanic were more likely to have been without a savings account over the period. Insights from this study will help inform policymakers and others interested in encouraging family financial security and resiliency through basic savings accounts.  相似文献   
259.
A cooperative program is reported which makes available to the school a series of group discussions on boy-girl relations, sexual physiology, venereal disease, and contraception. Girls attending these sessions, if they so desire, may attend the University Hospital Teen Clinic for physical examination and contraceptive supplies. One hundred and seventy students attended groups, of whom 74 attended teen clinics, and 61 became contraceptors. A second city high school has been added to the program. Staff believes that as young women learn that pregnancy is their choice, they will move into responsible relationships with ability to handle adequately planned motherhood.  相似文献   
260.
In this paper data from a nationally representative British longitudinal study are used to analyse exchanges of support between Third Age parents (aged 55-75) and their adult children. Results show that between two thirds and three quarters of parents in this age group were involved in some sort of exchange relationship with at least one of their children. Generally, more Third Age parents were providers than recipients of help, but there was a strong reciprocal element to intergenerational exchange with, for example, married parents who provided support to at least one child being twice as likely as those who did not to receive support from a child, after allowance for a range of relevant parental and child characteristics. Parental characteristics associated with higher probability of providing help included higher income, home ownership and being married or widowed rather than divorced. Higher income and home ownership were, however, negatively associated with odds of receiving help from a child, again after adjustment for other co-variates, suggesting socio-economic differences in the balance of support exchanges. Children seem responsive to parental needs in that receipt of help from a child was positively associated with older parental age and with parental disability. The paper shows that in Britain, as in the USA, the balance of intergenerational exchanges involving Third Age adults is downward rather than upward, in contravention of depictions of older adults as 'burdens' on younger generations. Current demographic and social changes are, it is argued, likely to increase support demands from adult children to Third Age parents in coming decades.  相似文献   
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