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Adolescents have begun to initiate sexual activity at increasingly early ages in the past few decades. Using a sample of 2,494 adolescents from the National Longitudinal Survey of Youth (NLSY97), structural and parental process variables were examined in the prediction of sexual onset. Results indicated that the age at which youth initiate sexual intercourse is related to the structural characteristics of their grandmothers and mothers, as well as puberty, gender, and race. There is support for partial mediation of the effects of these grandmother characteristics via mother characteristics and parental process. Results are discussed within the framework of the life course perspective and provide support for the importance of previous generations in the explanation of adolescent sexual behavior. Implications for families and adolescents are also addressed. Katherine A. Johnson, is a doctoral student at the University of Nebraska–Lincoln. Her research interests include the study of crime, gender, and high-risk youth using both qualitative and quantitative methodology. Kimberly A. Tyler, is an associate professor in the Department of Sociology at the University of Nebraska–Lincoln. Her research interests include homelessness, child abuse and neglect, victimization, and high-risk behaviors among adolescents and youth.  相似文献   
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Y-chromosome short tandem repeats (Y-STRs) provide valuable information in cases of rape and questioned paternity, and they allow for the genetic identification of male lineages. The present study validated a Y-STR 10-plex on the ABI PRISM 3100 Genetic Analyzer for use in forensic and paternity laboratories at Orchid Cellmark. Following optimization of the polymerase chain reaction, father-son pairs were analyzed to ensure that each pair generated identical haplotypes. This study demonstrated that the 10-plex is sensitive to 0.125 ng of input DNA and that female samples mixed with male samples did not interfere with Y-STR haplotyping. In a sample of 525 males, there were three instances of locus multiplication, two at DYS19 and one at DYS435. Overall, haplotype diversity was 0.996, suggesting that the 10-plex can effectively distinguish among male lineages.  相似文献   
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This study examined the prevalence of alcohol- and substance-related disorders in a random sample of 627 adult probationers in Illinois. The investigation also explored the prevalence of major psychiatric disorders and their co-occurrences with alcohol and substance use disorders. To detect the presence of psychiatric disorders, researchers employed standardized assessment tools based on Diagnostic and Statistical Manual of Mental Disorders criteria. Overall, results showed that probationers had significantly higher rates of psychiatric disorders, substance use disorders, and co-occurring disorders compared with persons in the general population. In light of these findings, probation administrators are urged to invest more resources in treating drug use, mental illness, and codisorders, the latter of which is associated with a higher risk of violent behaviors.  相似文献   
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The term Government Transfer Services is used in reference to any of the organized streams of public resources that flow into private economic activity. This includes such activities as offshore leasing, Social Security, and NASA technology transfer services. This paper describes a performance measure, empirical results, a theory, and a control model for such services. These are illustrated by a specific example (NASA). An agenda for developing this service control method is also presented.  相似文献   
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