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991.
During the last decade there has been a dramatic increase in the both the number and the rate of Mexican naturalization. Some have interpreted this increase as a response to changes in welfare and immigration policy surrounding the 1996 Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA), which limited public assistance to non‐citizens, and the 1996 Illegal Immigration Reform and Immigrant Responsibility Act (IIRIRA), which may have increased the incentive to naturalize by making it more difficult for legal immigrants to sponsor their relatives for entry to the United States. This article uses Current Population Survey data from 1994/95 and 2000/01 to examine how the social and economic determinants of naturalization may have changed in order to provide insight into which explanation for the increase in naturalizations is most relevant. We find that while the proportion of Mexican immigrants who are naturalized increased during the 1990s, their determinants have remained largely the same with the exception that those with noncitizen spouses have become more likely to be naturalized in the post‐reform period. This suggests that a more cautious interpretation be taken about the relationship between the increase in naturalizations and welfare and sponsorship restrictions, particularly when regarding Mexican immigrants. 相似文献
992.
993.
Estimating the reliability of repeatedly measured endpoints based on linear mixed‐effects models. A tutorial
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Wim Van der Elst Geert Molenberghs Ralf‐Dieter Hilgers Geert Verbeke Nicole Heussen 《Pharmaceutical statistics》2016,15(6):486-493
There are various settings in which researchers are interested in the assessment of the correlation between repeated measurements that are taken within the same subject (i.e., reliability). For example, the same rating scale may be used to assess the symptom severity of the same patients by multiple physicians, or the same outcome may be measured repeatedly over time in the same patients. Reliability can be estimated in various ways, for example, using the classical Pearson correlation or the intra‐class correlation in clustered data. However, contemporary data often have a complex structure that goes well beyond the restrictive assumptions that are needed with the more conventional methods to estimate reliability. In the current paper, we propose a general and flexible modeling approach that allows for the derivation of reliability estimates, standard errors, and confidence intervals – appropriately taking hierarchies and covariates in the data into account. Our methodology is developed for continuous outcomes together with covariates of an arbitrary type. The methodology is illustrated in a case study, and a Web Appendix is provided which details the computations using the R package CorrMixed and the SAS software. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
994.
Sonja N Sax P. Robinan Gentry Cynthia Van Landingham Harvey J. Clewell III Kenneth A. Mundt 《Risk analysis》2020,40(2):294-318
β-Chloroprene is used in the production of polychloroprene, a synthetic rubber. In 2010, Environmental Protection Agency (EPA) published the Integrated Risk Information System “Toxicological Review of Chloroprene,” concluding that chloroprene was “likely to be carcinogenic to humans.” This was based on findings from a 1998 National Toxicology Program (NTP) study showing multiple tumors within and across animal species; results from occupational epidemiological studies; a proposed mutagenic mode of action; and structural similarities with 1,3-butadiene and vinyl chloride. Using mouse data from the NTP study and assuming a mutagenic mode of action, EPA calculated an inhalation unit risk (IUR) for chloroprene of 5 × 10−4 per µg/m3. This is among the highest IURs for chemicals classified by IARC or EPA as known or probable human carcinogens and orders of magnitude higher than the IURs for carcinogens such as vinyl chloride, benzene, and 1,3-butadiene. Due to differences in pharmacokinetics, mice appear to be uniquely responsive to chloroprene exposure compared to other animals, including humans, which is consistent with the lack of evidence of carcinogenicity in robust occupational epidemiological studies. We evaluated and integrated all lines of evidence for chloroprene carcinogenicity to assess whether the 2010 EPA IUR could be scientifically substantiated. Due to clear interspecies differences in carcinogenic response to chloroprene, we applied a physiologically based pharmacokinetic model for chloroprene to calculate a species-specific internal dose (amount metabolized/gram of lung tissue) and derived an IUR that is over 100-fold lower than the 2010 EPA IUR. Therefore, we recommend that EPA's IUR be updated. 相似文献
995.
Der Ananian C Wilcox S Watkins K Saunders R Evans AE 《Journal of aging and physical activity》2008,16(2):125-143
Most people with arthritis are not regularly active. Understanding what factors influence exercise is essential for designing programs to increase participation. The objective of this study was to examine the correlates of exercise in people with arthritis. Using a cross-sectional design, sociodemographic, health-related, and psychosocial variables were collected from community-dwelling individuals with arthritis (N = 141). Associations with exercise level were examined with bivariate statistics (ANOVAs, chi-squares) and logistic-regression analyses. Exercisers were less likely than nonexercisers and insufficiently active people to report that arthritis negatively affected their physical and social functioning, and they reported more positive affect and greater self-efficacy (p < .05). Exercisers also reported less pain than nonexercisers (p < .05). In multiple logistic-regression analyses, self-efficacy and physical limitations remained independent predictors of exercise. The results suggest the need to target exercise self-efficacy when designing exercise interventions. Results also suggest the need to tailor exercise programs to individuals' physical limitations. 相似文献
996.
The Job Demand-Control (JDC) model (Karasek, 1979) and the Job Demand-Control-Support (JDCS) model (Johnson, and Hall, 1988) have dominated research on occupational stress in the last 20 years. This detailed narrative review focuses on the JDC(S) model in relation to psychological well-being. It covers research from 63 samples, published in the period 1979-1997. In the review a distinction is drawn between two different hypotheses prevailing in research on the models. According to the strain hypothesis of the JDC model, employees working in a high-strain job (high demands-low control) experience the lowest well-being. The buffer hypothesis states that control can moderate the negative effects of high demands on well-being. Translating these hypotheses to the expanded JDCS model, the iso-strain hypothesis predicts the most negative outcomes among workers in an iso-strain job (high demands-low control-low social support/isolation), whereas the buffer hypothesis states that social support can moderate the negative impact of high strain on well-being. Although the literature gives considerable support for the strain and iso-strain hypotheses, support for the moderating influence of job control and social support is less consistent. The conceptualization of demands and control is a key factor in discriminating supportive from nonsupportive studies. Only aspects of job control that correspond to the specific demands of a given job moderate the impact of high demands on well-being. Furthermore, certain subpopulations appear to be more vulnerable to high (iso)strain, whereas others benefit more from high control. On the basis of the results of this review, suggestions for future research and theoretical development are formulated. 相似文献
997.
Brigitte A. Bloem Theo G. Van Tilburg Fleur Thomése 《Journal of Housing for the Elderly》2013,27(1-2):28-47
The authors examined eight personal and contextual conditions associated with starting new relationships with neighbors after short- and long-distance moves. A total of 625 Dutch movers and 1,936 non-movers (57–93 years old) were selected from the Longitudinal Aging Study Amsterdam. OLS linear regression analyses showed that short-distance movers mainly started relationships with neighbors when they did volunteer work. Long-distance movers who moved to rural areas and felt safe in their new neighborhood or moved to areas with lower priced homes also started new relationships with neighbors. Contextual conditions appear to play a larger role than personal ones, especially after long-distance moves. 相似文献
998.
Carina Van Vliet Catharina P. B. Van der Ploeg Nancy Kidula Isaac M. Malonza Mark Tyndall Nico J. D. Nagelkerke 《Journal of sex research》2013,50(3):298-305
In mathematical models for predicting the spread of sexually transmitted diseases (STDs), the rate of acquisition of new sex partners and concurrency, the number of simultaneous sexual partnerships, are important parameters. Yet, information on these parameters is rarely obtained in routine sexual behavior surveys; instead, questions about the total number of sex partners during specific periods are often asked. We present two methods that estimate the rate of partnership acquisition and concurrency from reported numbers of sex partners in two overlapping periods. The first method assumes homogeneous behavior, while the second method also takes account of heterogeneity in sexual behavior. Both methods assume random (Poisson) partnership acquisition and the possibility of overlap in relationships. For both methods it might be relevant to distinguish individuals who are in a stable relationship from those who are not. 相似文献
999.
Brian R. Spisak Astrid C. Homan Allen Grabo Mark Van Vugt 《The Leadership Quarterly》2012,23(2):273-280
Using an evolutionary psychology framework we propose that leadership and followership are evolved traits to solve recurrent group coordination problems. We argue that adaptive problems such as those concerning intergroup conflict or cooperation activate different cognitive leadership prototypes, and the face conveys diagnostic information about the suitability and emergence of intergroup leadership. Consistent with hypotheses we find that followers expect masculine-faced leaders to behave competitively and feminine-faced leaders cooperatively in intergroup relations. Furthermore, individuals prefer leaders whose facial cues match the adaptive problem. For example, a masculine-looking leader is preferred in a competitive intergroup setting. Also, this match between face and situation is reinforced with a consistent leadership message such as a masculine-looking leader expressing the need for competition. An evolutionary perspective provides a deeper understanding of the biological aspects of leadership and generates many novel hypotheses about how markers such as the human face affect leadership emergence and effectiveness. 相似文献
1000.
Stormwater ponds now comprise a significant portion of standing water in urban areas. These ponds act to sequester excess
run-off and pollutants, such as road salt deicers. While these man-made ponds are not intended to serve as freshwater ecosystems,
it is becoming clear that they do provide habitat for many organisms, but we know little of their ecosystem structure, function
and interactions with pollutants. From April through June 2009, we surveyed 8 stormwater ponds in the Red Run Watershed, Baltimore
County, Maryland, USA to describe patterns in aquatic food webs associated with a gradient in road salt inputs. Periphyton,
phytoplankton and zooplankton samples were collected from each pond every 4–6 weeks. Specific conductance, a measure of chloride
salt loading, among the 8 ponds varied widely throughout the survey, ranging from 99 μS cm−1 to 19,320 μS cm−1. Low (average = 404 +/− 82.6 (SE) μS cm−1) and medium (average = 1749 +/− 267 (SE) μS cm−1) conductance ponds had lower algal biomass and higher densities of zooplankton taxa relative to high (average = 7231 +/−
2143 (SE) μS cm−1) conductance ponds, which were largely devoid of all zooplankton through the end of May. The observed decline in zooplankton
density along an increasing chloride gradient is consistent with experimental results of road deicer effects, suggesting algal
resources are possibly freed from grazing pressure as zooplankton consumers are negatively impacted by road salt exposure.
Our results highlight the potential for both direct and indirect effects of road deicers on freshwater communities. 相似文献