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141.
Urbanization poses threats to earth’s biota, and retention of remnant native habitat in protected areas within expanding urban boundaries may help alleviate threats to wildlife. However, it is unclear for nearly all nonsynanthropic (i.e., not benefiting from an association with humans) species whether vital rates in urban habitats can sustain populations or if populations persist only through immigration from outside the urban boundary. We conducted a three-year study of spotted towhees (Aves: Pipilo maculatus) breeding in four undeveloped parks in Portland, OR, USA, to measure park-specific seasonal reproductive output (F) and annual adult survival (SA). We developed a stochastic model that combined F and SA with an estimate of first-year survival to measure population growth rate (λ) in all parks assumed to be closed to immigration. F differed among parks but SA did not. Relatively high F was possible because many pairs raised >1 brood/season. When combined with empirical estimates of survival through the 30-day period of post-fledging parental care (SD = 0.645), only 2 of 4 parks were self-sustaining (i.e., λ > 1.0). However, SD reflected substantial loss of fledglings to domestic cats (Felis catus). Assuming no loss to cats and either partial compensatory or additive mortality of fledglings substantially improved prospects of population persistence for declining (sink) populations. Moreover, allowing low levels of immigration to sinks reversed population declines in most parks even when vital rates were insufficient to maintain populations. Our results suggest that nonsynanthropic bird species can persist in urban landscapes, but also that offspring mortality in the post-fledging period may be a critical determinant of population viability.  相似文献   
142.
143.
Across the United States, many afterschool and out-of-school time programs are making constructive and lasting impacts on the lives of homeless children and youth by providing expanded learning opportunities and positive youth development outcomes in a safe space. In this brief, we profile two youth-serving organizations and the After School Division of the California Department of Education to illustrate how afterschool programs can be part of the solution for homeless children and youth. Staff from these organizations shared their practices, successes, challenges, and lessons learned. Most importantly, they shared a message of hope and a vision for what is possible in the midst of trauma, uncertainty, and displacement.  相似文献   
144.
The methods used when samples of journal articles are treated as the basis for measuring levels of quantification in national sociologies are examined. The data come from every identified example in English. It is found that operational definitions of ‘quantitative’ vary, while ‘qualitative’ work is characterised simply by the absence of sophisticated quantification, which is sometimes taken to imply quantitative incompetence rather than methodological choice. The articles used as data on the state of a whole national sociology are usually drawn from elite general journals in which many sociologists have never published, and ignore the authors’ national backgrounds and publications elsewhere. It is concluded that there is a gap between concepts and operational definitions which it would be desirable to fill.  相似文献   
145.
This study examines how preadolescent African American students in Washington, D.C., used a linguistic practice called ‘joning,’ a style of verbal play similar to ritual insults, in peer interactions. Sociolinguists have focused on how children socialize each other into vernacular styles appropriate for peer group use but often assume that they disalign with social and linguistic norms for classroom behavior. Drawing from a nine‐month ethnographic study that the author conducted in an after‐school program, this article analyzes the structure and function of joning as a vernacular style of African American Vernacular English and its uses in constructing classroom identities. Joning often facilitated student learning, but it was perceived as a socially and physically risky linguistic practice because of its uses as conflict talk in the local community. Focusing on preadolescence as a key stage of language socialization, this article shows how minority students modify peer‐learned linguistic practices to pursue academic success on their own terms.  相似文献   
146.
The current study explored two possible comparison groups for the double Face‐to‐Face Still‐Face (FFSF) paradigm to evaluate their effects on infant behavior and different hypotheses about the nature of the Still‐Face (SF) effect, an effect not fully understood. Mothers and their 4‐month‐old infants were randomly assigned to one of three groups, a double FFSF group (GroupFFSF, n = 44), a control, semi‐structured play group (GroupStory, n = 46), or a control, unstructured play group (GroupPlay, n = 28). As hypothesized, GroupFFSF infants exhibited the classic SF response (decreased positive affect and gaze to mother; increased negative affect) and GroupPlay infants showed an increase in negative affect over episodes. Contrary to expectations, GroupStory infants displayed a similar, but less intense, pattern of behavior as GroupFFSF. Taken together, the findings indicate that multiple episodes of face‐to‐face play exceeded 4‐month‐olds' regulatory capacities and that infants are sensitive to shared communicative intentions and violations of social expectations, whether these violations are negative or positive in nature.  相似文献   
147.
148.
Alcohol and marijuana use are thought to increase sexual risk taking, but event-level studies conflict in their findings and often depend on reports from a limited number of people or on a limited number of sexual events per person. With event-level data from 1,856 sexual intercourse events provided by 297 college women (M age = 18 years; 71% White), we used multilevel modeling to examine associations between alcohol and marijuana use and condom use as well as interactions involving sexual partner type and alcohol-sexual risk expectancies. Controlling for alternative contraception use, partner type, regular levels of substance use, impulsivity and sensation seeking, and demographics, women were no more or less likely to use condoms during events involving drinking or heavy episodic drinking than during those without drinking. However, for drinking events, there was a negative association between number of drinks consumed and condom use; in addition, women with stronger alcohol-sexual risk expectancies were marginally less likely to use condoms when drinking. Although there was no main effect of marijuana use on condom use, these data suggest marijuana use with established romantic partners may increase risk of unprotected sex. Intervention efforts should target expectancies and emphasize the dose-response relationship of drinks to condom use.  相似文献   
149.
“Hookups” are sexual encounters between partners who are not in a romantic relationship and do not expect commitment. We examined the associations between sexual hookup behavior and depression, sexual victimization (SV), and sexually transmitted infections (STIs) among first-year college women. In this longitudinal study, 483 women completed 13 monthly surveys assessing oral and vaginal sex with hookup and romantic partners, depression, SV, and self-reported STIs. Participants also provided biological specimens that were tested for STIs. During the study, 50% of participants reported hookup sex and 62% reported romantic sex. Covariates included previous levels of the outcome, alcohol use, impulsivity, sensation seeking, and romantic sex. Autoregressive cross-lagged models showed that, controlling for covariates, hookup behavior during college was correlated with depression, Bs = .21, ps < .05, and SV, Bs = .19, ps < .05. In addition, precollege hookup behavior predicted SV early in college, B = .62, p < .05. Hookup sex, OR 1.32, p < .05, and romantic sex, OR 1.19, p < .05, were associated with STIs. Overall, sexual hookup behavior among college women was positively correlated with experiencing depression, SV, and STIs, but the nature of these associations remains unclear, and hooking up did not predict future depression.  相似文献   
150.
On the basis of theories of maternal identity development, role conflict, and childbearing motivation, the authors tested whether high educational aspirations among pregnant adolescents are related to the unwantedness of the pregnancy and whether pregnancy unwantedness leads to subsequent parenting stress and inadequacy. Longitudinal data from 100 first‐time‐pregnant, unmarried Latina adolescents (M age = 17.3 years) were analyzed. Results from structural equation path modeling confirmed these associations, with strong educational ambitions related to greater unwantedness of the pregnancy, which led to feeling trapped by parenting at 6 months postpartum, which in turn was related to unaffectionate parenting and feeling inadequate in mothering at 1 year postpartum. The potential long‐term negative consequences of high educational aspirations for pregnant adolescents' adjustment to parenting are discussed.  相似文献   
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