Individual Differences in Women's Salivary Testosterone and Estradiol Following Sexual Activity in a Nonlaboratory Setting

Objectives: The current study evaluated women's salivary testosterone and estradiol levels before and after exposure to sexual stimuli in a U.S. sex club. Methods: Behavioral data and salivary samples were collected from 19 women during semistructured interviews. Results: Findings demonstrate substantial individual differences in the magnitude and direction of women's hormonal changes following sexual activity. Conclusions: In an age of individualized medicine, these findings highlight the need to better understand factors shaping variation in physiological responses to sexual activity. Findings contribute to a relatively small and contradictory literature on women's hormonal responses to sexual stimuli.     

工业缝纫机针杆的气浮轴承性能数值计算与分析

为了对气浮针杆的小孔节流型轴承的支承性能进行研究,文章在建立数学模型的基础上,运用有限差分法对控 制方程进行数值有限差分的推导,利用MATLAB对针杆在低速和高速的情况下的压力分布进行了数值求解。结果表 明：气浮轴承能够较好地实现工业缝纫机的低速和高速情况下的气浮支承;双排节流小孔的压力分布承载效果比单排节 流小孔好;随着气浮针杆运动速度的变化双排节流小孔的气浮轴承的稳定性较好。对进一步深入对工业缝纫机针杆的 气浮支承研究具有指导意义。     

Parental Influence on Friendships Between Native and Immigrant Adolescents

Parental influence on friendships between native (N = 5,683) and immigrant (N = 3,371) adolescents (aged ± 15) was investigated with the CILS4EU data of pupils in German and Dutch school classes (N = 446) and parents. The researchers examined whether parents affect friendships across group boundaries by shaping the structural opportunities to establish out‐group friends and their children's out‐group attitudes. The results show that if parents have more out‐group friends and if they consider it less important to maintain in‐group traditions, their children have more out‐group friends. Part of this relationship is mediated by children's out‐group attitudes. Some evidence is found that the opportunity structure mediates the relationship between parental characteristics and adolescent out‐group friendship.     

Same-Gender Sexual Partnering: A Re-Analysis of Trend Data

Numerous studies have been carried out to estimate the prevalence of same-gender sexual behavior. Among studies conducted in recent years, few confirm the commonly quoted figure of 10%. Yet several studies in the early 2000s indicated that the prevalence of same-gender sex may be increasing, especially among women. This article reexamines the trends identified in previous research by using General Social Survey data from 1988 to 2010 and by focusing on multiple measures of same-gender sex over time. Results indicate that for both women and men the likelihood of having had a same-gender sexual partner since age 18 continued to increase through the 2000s, but that the likelihood of having had a same-gender sexual partner in both the past year and in the past five years leveled off for women and reversed for men. Results also indicate that the percentage of people reporting a pattern of predominantly same-gender sexual behavior has neither increased nor decreased over time. A similar result was found among persons who reported being in a same-gender sexual relationship. Overall, results paint a more complex picture than prior studies in characterizing trends in same-gender sexual behavior.     

The analytic construction of D-optimal designs for the two-variable binary logistic regression model without interaction

Candidate locally D-optimal designs for the binary two-variable logistic model with no interaction, which comprise 3 and 4 support points lying in the first quadrant of the two-dimensional Euclidean space, were introduced by Haines et al. (D-optimal designs for logistic regression in two variables. In: Lopez-Fidalgo J, Rodrigez-Diaz JM, Torsney B, editors. MODA8 – advances in model-oriented designs and analysis. Heidelberg: Physica-Verlag; 2007. p. 91–98). The authors proved algebraically the global D-optimality of the 3-point design for the special case in which the intercept parameter is equal to?1.5434. However for other selected values of the intercept parameter, the global D-optimality of the proposed 3- and 4-point designs was only demonstrated numerically. In this paper, we provide analytical proofs of the D-optimality of these 3- and 4-point designs for all negative and zero intercept parameters of the binary two-variable logistic model with no interaction. The results are extended to the construction of D-optimal designs on a rectangular design space and illustrated by means of two examples of which one is a real example taken from the literature.     

To adjust or not to adjust for baseline when analyzing repeated binary responses? The case of complete data when treatment comparison at study end is of interest

The benefits of adjusting for baseline covariates are not as straightforward with repeated binary responses as with continuous response variables. Therefore, in this study, we compared different methods for analyzing repeated binary data through simulations when the outcome at the study endpoint is of interest. Methods compared included chi‐square, Fisher's exact test, covariate adjusted/unadjusted logistic regression (Adj.logit/Unadj.logit), covariate adjusted/unadjusted generalized estimating equations (Adj.GEE/Unadj.GEE), covariate adjusted/unadjusted generalized linear mixed model (Adj.GLMM/Unadj.GLMM). All these methods preserved the type I error close to the nominal level. Covariate adjusted methods improved power compared with the unadjusted methods because of the increased treatment effect estimates, especially when the correlation between the baseline and outcome was strong, even though there was an apparent increase in standard errors. Results of the Chi‐squared test were identical to those for the unadjusted logistic regression. Fisher's exact test was the most conservative test regarding the type I error rate and also with the lowest power. Without missing data, there was no gain in using a repeated measures approach over a simple logistic regression at the final time point. Analysis of results from five phase III diabetes trials of the same compound was consistent with the simulation findings. Therefore, covariate adjusted analysis is recommended for repeated binary data when the study endpoint is of interest. Copyright © 2015 John Wiley & Sons, Ltd.