Hypotheses Testing on a Multivariate Null Intercept Errors-in-Variables Model

Considering the Wald, score, and likelihood ratio asymptotic test statistics, we analyze a multivariate null intercept errors-in-variables regression model, where the explanatory and the response variables are subject to measurement errors, and a possible structure of dependency between the measurements taken within the same individual are incorporated, representing a longitudinal structure. This model was proposed by Aoki et al. (2003b Aoki , R. , Bolfarine , H. , Achcar , J. A. , Pinto Jr. , D. L. ( 2003b ). Bayesian analysis of a multivariate null intercept errors-in-variables regression model . Journal of Biopharmaceutical Statistics 13 : 767 – 775 .[Taylor & Francis Online] , [Google Scholar]) and analyzed under the bayesian approach. In this article, considering the classical approach, we analyze asymptotic test statistics and present a simulation study to compare the behavior of the three test statistics for different sample sizes, parameter values and nominal levels of the test. Also, closed form expressions for the score function and the Fisher information matrix are presented. We consider two real numerical illustrations, the odontological data set from Hadgu and Koch (1999 Hadgu , A. , Koch , G. ( 1999 ). Application of generalized estimating equations to a dental randomized clinical trial . Journal of Biopharmaceutical Statistics 9 ( 1 ): 161 – 178 .[Taylor & Francis Online] , [Google Scholar]), and a quality control data set.     

Controlling birth: science, politics, and public policy

Reproductive technologies raise a host of social and legal issues that challenge basic values and create intense controversy. If researchers wish to inform public policies related to reproductive technologies, they must understand how the scientific enterprise is being manipulated and research findings are being misrepresented to justify a particular social agenda and restrict access to contraception and abortion. To counter these distortions, scientists must defend the science advisory process, be involved in dissemination of their research findings beyond simple publication in scientific journals, and actively work to ensure that the findings are not misrepresented to the public .     

Criminal Victimization and Crime Risk Perception: A Multilevel Longitudinal Study

In a national sample of the Italian population, surveyed four times between October 2002 and January 2007 (N = 2,008), we performed a multilevel longitudinal study aimed at predicting the increase in crime risk perception as a function of three families of independent variables, respectively lying at the within individual level (direct victimization and indirect victimization), at the between-individuals level (being a woman, being an older person, being a poorly educated person and size of area of residence) and at the ecological level (county’s crime rate, unemployment rate and immigration rate). Direct and indirect victimization, being a woman, being an older person, living in a large town and in a context characterized by high crime and unemployment rates positively influenced the change in crime risk perception, while the other individual and ecological predictors we used in our predictive model did not. Strengths, limitations, implications and future developments of this research are discussed.     

Stability and Change in Youths’ Political Interest

Political interest is a key for the survival and development of democracies. Therefore, it is important to establish when political interest develops. We examined changes in political interest—when and in which directions—among youths between 13 and 28 years of age. We followed five age groups of Swedish youths over 2 years, with a total of 2621 participants. Analysis of stability coefficients supported the idea that political interest becomes more stable with age. From their early twenties, youths’ political interest was found to be as stable as has been earlier reported for adults. Among adolescents, the lowest stability rate was observed in the youngest cohort (ages 13–15). The results also showed that, when taking the increase in political interest into account, the proportion of youths losing their interest in politics corresponded to the proportion of youths gaining interest over time. On the whole, this study brings new insights on the development of political interest over time. It provides empirical evidence on when political interest is most susceptible to change and on how it is likely to change. Implications for research and intervention are discussed.     

Nonlinear mixed-effects models with scale mixture of skew-normal distributions

Aiming to avoid the sensitivity in the parameters estimation due to atypical observations or skewness, we develop asymmetric nonlinear regression models with mixed-effects, which provide alternatives to the use of normal distribution and other symmetric distributions. Nonlinear models with mixed-effects are explored in several areas of knowledge, especially when data are correlated, such as longitudinal data, repeated measures and multilevel data, in particular, for their flexibility in dealing with measures of areas such as economics and pharmacokinetics. The random components of the present model are assumed to follow distributions that belong to scale mixtures of skew-normal (SMSN) distribution family, that encompasses distributions with light and heavy tails, such as skew-normal, skew-Student-t, skew-contaminated normal and skew-slash, as well as symmetrical versions of these distributions. For the parameters estimation we obtain a numerical solution via the EM algorithm and its extensions, and the Newton-Raphson algorithm. An application with pharmacokinetic data shows the superiority of the proposed models, for which the skew-contaminated normal distribution has shown to be the most adequate distribution. A brief simulation study points to good properties of the parameter vector estimators obtained by the maximum likelihood method.     

Efficacy of a Facial Emotion Training Program for Children and Adolescents with Autism Spectrum Disorders

Twenty-five high-functioning, verbal children and adolescents with autism spectrum disorders (ASD; age range 8–15 years) who demonstrated a facial emotion recognition deficit were block randomized to an active intervention (n = 12) or waitlist control (n = 13) group. The intervention was a modification of a commercially-available, computerized, dynamic facial emotion training tool, the MiX by Humintell©. Modifications were introduced to address the special learning needs of individuals with ASD and to address limitations in current emotion recognition programs. Modifications included: coach-assistance, a combination of didactic instruction for seven basic emotions, scaffold instruction which included repeated practice with increased presentation speeds, guided attention to relevant facial cues, and imitation of expressions. Training occurred twice each week for 45–60 min across an average of six sessions. Outcome measures were administered prior to and immediately after treatment, as well as after a delay period of 4–6 weeks. Outcome measures included (a) direct assessment of facial emotion recognition, (b) emotion self-expression, and (c) generalization through emotion awareness in videos and stories, use of emotion words, and self-, parent-, and teacher-report on social functioning questionnaires. The facial emotion training program enabled children and adolescents with ASD to more accurately and quickly identify feelings in facial expressions with stimuli from both the training tool and generalization measures and demonstrate improved self-expression of facial emotion.     

Association between dietary phytoestrogens intakes and prostate cancer risk in Sicily

Objective: In this study we aimed to investigate the association between dietary phytoestrogen consumption and prostate cancer in a sample of southern Italian individuals.

Methods: A population-based case-control study on the association between prostate cancer and dietary factors was conducted from January 2015 to December 2016 in a single institution of the municipality of Catania, southern Italy (Registration number: 41/2015). A total of 118 histopathological-verified prostate cancer (PCa) cases and a total of 222 controls were collected. Dietary data was collected by using two food frequency questionnaires.

Results: Patients with PCa consumed significantly higher levels of phytoestrogens. Multivariate logistic regression showed that lignans (Q[quartile]4 vs. Q1, OR [odds ratio]?=?4.72; p?p?p?p?p?p?p?Conclusion: We found of an inverse association between dietary isoflavone intake and PCa, while a positive association was found with lignans intake.     

Effects of strength and power training on neuromuscular variables in older adults

The purpose of this study was to compare the neuromuscular adaptations produced by strength-training (ST) and power-training (PT) regimens in older individuals. Participants were balanced by quadriceps cross-sectional area (CSA) and leg-press 1-repetition maximum and randomly assigned to an ST group (n = 14; 63.6 ± 4.0 yr, 79.7 ± 17.2 kg, and 163.9 ± 9.8 cm), a PT group (n = 16; 64.9 ± 3.9 yr, 63.9 ± 11.9 kg, and 157.4 ± 7.7 cm), or a control group (n = 13; 63.0 ± 4.0 yr, 67.2 ± 10.8 kg, and 159.8 ± 6.8 cm). ST and PT were equally effective in increasing (a) maximum dynamic and isometric strength (p < .05), (b) increasing quadriceps muscle CSA (p < .05), and (c) decreasing electrical mechanical delay of the vastus lateralis muscle (p < .05). There were no significant changes in neuromuscular activation after training. The novel finding of the current study is that PT seems to be an attractive alternative to regular ST to maintain and improve muscle mass.