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161.
We consider asymptotic properties of the maximum likelihood and related estimators in a clustered logistic joinpoint model with an unknown joinpoint. Sufficient conditions are given for the consistency of confidence bounds produced by the parametric bootstrap; one of the conditions required is that the true location of the joinpoint is not at one of the observation times. A simulation study is presented to illustrate the lack of consistency of the bootstrap confidence bounds when the joinpoint is an observation time. A removal algorithm is presented which corrects this problem, but at the price of an increased mean square error. Finally, the methods are applied to data on yearly cancer mortality in the US for individuals age 65 and over. 相似文献
162.
By using data from the National Longitudinal Study of Adolescent Health, we examine how adolescent relationship characteristics, partner attributes, and sexual relationship histories are associated with contraceptive use and consistency, incorporating random effects to control for respondent-level unobserved heterogeneity. Analyses show that teens' contraceptive use patterns vary across relationships. Teens with more-homogamous partners, with more-intimate relationships, and who communicate about contraception before sex have greater odds of contraceptive use and/or consistency. Teens in romantic relationships, and who are older when engaging in sex for the first time, have greater odds of ever using contraceptives but reduced odds of always using contraceptives. Teens continue habits from previous relationships: teens with experience practicing contraceptive consistency and females who previously have used hormonal contraceptive methods are better able to maintain consistency in subsequent relationships. Also, relationship and partner characteristics are less important for females who previously used hormonal methods. 相似文献
163.
Maureen C. Kenny Vjolca Capri Reena R. Thakkar‐Kolar Erika E. Ryan Melissa K. Runyon 《Child Abuse Review》2008,17(1):36-54
There are a growing number of child abuse prevention and education programmes, including primarily group‐based parent and child education, which are taught by teachers within the school system. This article reviews some of the existing sexual abuse education and/or body safety programmes, as well as the research surrounding them. Advantages as well as criticisms of such programmes are reviewed. Issues such as target populations (i.e. children, teachers, parents), programme components and methodological limitations are addressed. Major findings include: children as young as three can be effectively taught self‐protection skills, parental and family involvement in training is important, and repeated exposure helps children maintain knowledge gains. The components of successful programmes include teaching children to identify and resist inappropriate touching, reassuring children that it is not their fault and learning the proper names of their genitals. Finally, future directions for programme development, research and policy are explored. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
164.
165.
A population's long-term exposure distribution for a specified compound is typically estimated from short-term measurements of a sample of individuals from the population of interest. In this situation, estimates of a population's long-term exposure parameters contain two sources of sampling error: the typical sampling error associated with taking a sample from the population and the sampling error from estimating individual long-term exposure. These components are not separable in the data collected, i.e. , the value observed is due partly to the individual sampled and partly to the time at which the individual was sampled. Hence, the distribution of the data collected is not the same as the population exposure distribution. Monte Carlo simulations are used to compare the distribution of the observed data with the population exposure distribution for a simple additive model. A simple adjustment to standard estimates of percentiles and quantils is shown to be effective in reducing bias particularly for the upper percentiles and quantils of the population distribution. 相似文献
166.
Neuroimaging research has brought major advances to child health and wellbeing. However, because of the vulnerabilities associated with neurological and developmental conditions, the parental need for hope, and the expectation of parents that new medical advances can benefit their child, pediatric neuroimaging research presents significant challenges to the general problem of consent in the context of research involving children. A particular challenge in this domain is created by the presence of therapeutic misconception on the part of parents and other key research stakeholders. This article revierws the concept of therapeutic misconception and its role in pediatric neuroimaging research. It argues that this misconception can compromise consent given by parents for the involvement of their children in research as healthy controls or as persons with neurological and developmental conditions. The article further contends that therapeutic misconception can undermine the research ethics review process for proposed and ongoing neuroimaging studies. Against this backdrop, the article concludes with recommendations for mitigating the effects of therapeutic misconception in pediatric neuroimaging research. 相似文献
167.
Too Cool for School? The Relationship between Coolness and Academic Reputation in Early Adolescence
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The relationship between peer‐nominated coolness and academic reputation was examined at two time points spanning the first year of middle school (N = 807; 52 percent female; 52 percent African‐American; 48 percent European American). Students predominantly nominated peers who were from their same gender and ethnic group as being cool. Associations between coolness and academic reputation differed across subgroups, were contingent upon level of disruptive behavior, and changed over time from fall to spring of the academic year. In the fall, patterns differed by gender, not by ethnicity. For both white and African‐American boys, hierarchical regressions evidenced a null association between coolness and academic reputation; for both white and African‐American girls, this association was positive. In the spring, findings for white girls were similar to findings from the fall. For the three remaining groups—white boys and African‐American boys and girls—conditions worsened over time, albeit in slightly dissimilar ways. For white boys, fall coolness did not predict significant declines in academic reputation over time; nonetheless, as a group, the coolness–academic reputation was negative by the end of the year. For African‐American boys and girls, fall coolness significantly predicted declines in academic reputation from fall to spring, although the concurrent coolness–academic reputation association was not significantly negative for either group in the spring. 相似文献
168.
Caroline E. Shanholtz Sacha Devine Brown Ryan D. Davidson Connie J. Beck 《Journal of divorce & remarriage》2019,60(2):141-151
Young adults from divorced families experience clear emotional distress despite most not meeting diagnostic criteria for emotional disorders. Laumann-Billings and Emery (2000) developed the Painful Feelings About Divorce (PFAD) scale to assess the emotional distress emerging adults feel regarding childhood parental divorce. The study sample is undergraduates predominately between the ages of 18 and 22. This study adds to the literature by (a) further demonstrating the PFAD scale reliability and validity, (b) including participants with both divorced and separated but never married parents, and (c) assessing generalizability of the PFAD with a more diverse socioeconomic sample. 相似文献
169.
Recently, many articles have obtained analytical expressions for the biases of various maximum likelihood estimators, despite their lack of closed-form solution. These bias expressions have provided an attractive alternative to the bootstrap. Unless the bias function is “flat,” however, the expressions are being evaluated at the wrong point(s). We propose an “improved” analytical bias-adjusted estimator, in which the bias expression is evaluated at a more appropriate point (at the bias adjusted estimator itself). Simulations illustrate that the improved analytical bias-adjusted estimator can eliminate significantly more bias than the simple estimator, which has been well established in the literature. 相似文献
170.
Doug P. VanderLaan Lanna J. Petterson Ryan W. Mallard Paul L. Vasey 《Journal of sex research》2015,52(6):710-720
Samoan transgendered males are known as fa'afafine. Although Samoan women are characterized as the primary child care providers, fa'afafine report elevated willingness to invest in nieces and nephews compared to men and women. We hypothesized that Samoans hold unique transgender role expectations such that fa'afafine are expected to invest more toward nieces and nephews compared to others. Participants (N = 214) included Samoan men (30.23 years ±8.19), women (30.00 years ±10.93), and fa'afafine (30.25 years ±7.45). For a variety of child care activities, participants nominated men, women, fa'afafine, or all three of these categories of individuals as responsible for investing toward nieces and nephews. Participants also reported how frequently their family members asked them to perform these activities for nieces and nephews. Responsibility for performing these activities was typically designated for women; men and women viewed fa'afafine as least responsible. Men's, but not fa'afafine's, family members asked them to allocate investment toward nieces and nephews more frequently. These findings are not consistent with the transgender role expectation hypothesis. Discussion details how the findings contribute to the literature on child care in Samoa. Alternate hypotheses for explaining why fa'afafine report elevated willingness to invest in nieces and nephews are considered. 相似文献