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61.
Evan Senreich 《Journal of homosexuality》2015,62(4):433-462
There is virtually no literature concerning the experiences of self-identified heterosexual clients in substance abuse treatment who have a history of same-gender sexual contact (HSGS). In a U.S. urban inpatient program in 2009–2010, 99 HSGS clients were compared to 681 other heterosexual and 86 lesbian, gay, and bisexual clients regarding background factors, program completion rates, and feelings about treatment. Male HSGS participants had lower completion rates than other male heterosexual participants. Qualitative data indicated that most male HSGS participants experienced difficult emotions regarding same-gender sexual encounters, particularly those involving trading sex for money or drugs. Implications for treatment are discussed. 相似文献
62.
Evolutionary ecology is the study of evolutionary processes, and the ecological conditions that influence them. A fundamental paradigm underlying the study of evolution is natural selection. Although there are a variety of operational definitions for natural selection in the literature, perhaps the most general one is that which characterizes selection as the process whereby heritable variation in fitness associated with variation in one or more phenotypic traits leads to intergenerational change in the frequency distribution of those traits. The past 20 years have witnessed a marked increase in the precision and reliability of our ability to estimate one or more components of fitness and characterize natural selection in wild populations, owing particularly to significant advances in methods for analysis of data from marked individuals. In this paper, we focus on several issues that we believe are important considerations for the application and development of these methods in the context of addressing questions in evolutionary ecology. First, our traditional approach to estimation often rests upon analysis of aggregates of individuals, which in the wild may reflect increasingly non-random (selected) samples with respect to the trait(s) of interest. In some cases, analysis at the aggregate level, rather than the individual level, may obscure important patterns. While there are a growing number of analytical tools available to estimate parameters at the individual level, and which can cope (to varying degrees) with progressive selection of the sample, the advent of new methods does not reduce the need to consider carefully the appropriate level of analysis in the first place. Estimation should be motivated a priori by strong theoretical analysis. Doing so provides clear guidance, in terms of both (i) assisting in the identification of realistic and meaningful models to include in the candidate model set, and (ii) providing the appropriate context under which the results are interpreted. Second, while it is true that selection (as defined) operates at the level of the individual, the selection gradient is often (if not generally) conditional on the abundance of the population. As such, it may be important to consider estimating transition rates conditional on both the parameter values of the other individuals in the population (or at least their distribution), and population abundance. This will undoubtedly pose a considerable challenge, for both single- and multi-strata applications. It will also require renewed consideration of the estimation of abundance, especially for open populations. Thirdly, selection typically operates on dynamic, individually varying traits. Such estimation may require characterizing fitness in terms of individual plasticity in one or more state variables, constituting analysis of the norms of reaction of individuals to variable environments. This can be quite complex, especially for traits that are under facultative control. Recent work has indicated that the pattern of selection on such traits is conditional on the relative rates of movement among and frequency of spatially heterogeneous habitats, suggesting analyses of evolution of life histories in open populations can be misleading in some cases. 相似文献
63.
Evan Osborne 《Journal of Labor Research》2000,21(3):463-475
conclusion My approach for the first time connects profit maximization to work force composition given full information. Physical productivity,
which dominates so much popular dis-cussion of this issue, matters, but demand-side factors are also important. Defining a
firm’s optimal work force composition is nonsensical until at least the product’s char-acteristics, the extent to which different
markets value them, and the extent to which groups inherently differ in their capacity to provide them are precisely defined. 相似文献
64.
Evan G. Cooch 《Journal of applied statistics》2002,29(1-4):143-162
In many birds, body size at fledging is assumed to predict accurately the probability of subsequent survival, and size at fledging is often used as a proxy variable in analyses attempting to assess the pattern of natural selection on body size. However, in some species, size at fledging can vary significantly as a function of variation in the environmental component of growth. Such developmental plasticity has been demonstrated in several species of Arctic-breeding geese. In many cases, slower growth and reduced size at fledging has been suggested as the most parsimonious explanation for reduced post-fledging survival in goslings reared under poor environmental conditions. However, simply quantifying a relationship between mean size at fledging and mean survival rate (Francis et al ., 1992) may obscure the pattern of selection on the interaction of the genetic and environmental components of growth. The hypothesis that selection operates on the environmental component of body size at fledging, rather than the genetic component of size per se, was tested using data from the long-term study of Lesser Snow Geese ( Anser c. caerulescens ) breeding at La Pérouse Bay, Manitoba, Canada. Using data from female goslings measured at fledging, post-fledging survival rates were estimated using combined live encounter and dead recovery data (Burnham, 1993). To control for the covariation between growth and environmental factors, survival rates were constrained to be functions of individual covariation of size at fledging, and various measures of the timing of hatch; in all Arctic-breeding geese studied to date, late hatching goslings grow significantly more slowly than do early hatching goslings. The slower growth of late-hatching goslings has been demonstrated to reflect systematic changes in the environmental component of growth, and thus controlling for hatch date controls for a significant proportion of variation in the environmental component of growth. The relationship between size at fledging, hatch date and survival was found to be significantly non-linear; among early hatching goslings, there was little indication of significant differences in survival rate among large and small goslings. However, with increasingly later hatch dates, there was progressively greater mortality selection against smaller, slower growing goslings in most years. This would appear to suggest that body size matters, but not absolutely; small size leads to reduced survival for late-hatching goslings only at La Pe´rouse Bay. Since at least some of the variation in size among goslings for a given hatch date reflects genetic differences, this suggests selection may favour larger size at fledging, albeit only among late-hatching goslings. 相似文献
65.
The estimation of survival rates from analysis of recapture of individually marked animals assumes that all individuals are equally likely to be re-encountered. This assumption is frequently violated in natural populations due to movements to and from the sampling area. We evaluated potential sources of heterogeneity using data from recaptures of 36000 individually marked female lesser snow geese, Anser c. caerulescens , from an expanding population in northern Manitoba, Canada. By stratifying individuals according to marking age and origin (hatched at the colony or not), we assessed the degree to which variation in apparent survival reflected permanent or temporary differences in emigration and effects of handling. In general, for birds ringed as adults, estimated apparent survival rates were significantly lower during the first year after ringing than in subsequent years. By comparing birds ringed as adults (classified by origin) with those ringed as goslings, we were able to demonstrate that these differences are not due to permanent emigration from the colony by transient individuals or heterogeneity of individual capture probability, but more likely reflect differences among individuals in their response to initial marking. Approximately 25% of birds permanently emigrate from the sampling area following marking. 相似文献
66.
67.
Evan K. Perrault 《Journal of American college health : J of ACH》2013,61(8):813-816
ABSTRACTObjective: To examine current knowledge and perceptions toward primary care providers commonly staffed at student health centers (PAs and NPs), and also assess the effectiveness of information-rich provider biographies to improve knowledge and perceptions. Participants: One thousand six hundred forty six students from 2 universities in 2 states participated in this study from February to November, 2016. Methods: An online survey. Students were exposed to an improved biography of an NP discussing how she can perform many of the same duties as primary care physicians. Changes in knowledge and perceptions were assessed pre- and post-biography exposure. Results: More than half of students are unaware NPs and PAs can prescribe medications and diagnose illnesses. Students exposed to the biography increased their knowledge of NPs, and perceptions of their expertise. Conclusions: Results suggest improved provider biographies on student health centers' websites can help reduce the knowledge deficit that exists among students regarding common primary care providers. 相似文献
68.
Evan Senreich Lydia P. Ogden Joy Pastan Greenberg 《Journal of Social Work Education》2013,49(2):260-275
ABSTRACTScreening, Brief Intervention, and Referral to Treatment (SBIRT) is an evidence-based protocol that addresses both moderate-risk and high-risk substance use problems for individuals. In an urban college’s master’s and bachelor’s social work programs with 218 students, SBIRT training was introduced into core course curricula, with many students subsequently using SBIRT in their field placements. Evaluation of the initiative demonstrated increases in the students’ knowledge and favorable attitudes regarding working with substance using clients. Students’ ratings of the usefulness and effectiveness of SBIRT were high. In response to studies indicating the lack of preparedness of graduating social work students to work with substance users, this study demonstrated the effectiveness of SBIRT training to educate students to work with this population. 相似文献
69.
Explanations for the increase of employment for American mothers with young children have focused on womens motivations and skills or on increased wages. Instead, this analysis considers how access to professional and managerial occupations may explain this employment trend. Relying on Current Population Survey data (1968–1995), the study reports that growing availability of these occupations explains less than 1/4 of employment growth. The percentage of full-time employed newer mothers in professional and managerial occupations, while having grown substantially over time, remains relatively small. Part-time employment does not explain the trend. Relatively high rates of full-time work, even for low-prestige occupations, affirm existing research emphasizing family economic need and validate questions about the structure of work for accommodating family obligations.The author thanks Paul Burstein, Charles Hirschman, Sharon Reitman, and the anonymous reviewers of JFEI for their helpful comments. An earlier version of this paper was presented at the annual meetings of the American Sociological Association in Washington, DC, August 2000. 相似文献
70.
Objective . We estimate a model of social-psychological determinants of entry into Aid to Families with Dependent Children (AFDC), the primary cash welfare program in the United States until 1996. Methods . Using information from the youngest cohorts of the National Longitudinal Survey of Youth, we estimate logit models of the probability of ever participating in AFDC and hazard models of the timing until first use of AFDC. Results . We find strong associations between welfare use and several attitudes and personality characteristics, but with two exceptions, most of the associations are not robust to the inclusion of exogenous background characteristics. There is consistent, strong evidence that positive attitudes toward school lower the likelihood of using welfare and increase duration until first receipt. Family background and social environment characteristics show strong robust effects. Conclusions . Our results point to relatively weak evidence for the hypothesis that individual attitudes in adolescence have a significant impact on initial welfare receipt. 相似文献