On Testing Changes in Autoregressive Parameters of a VAR Model

The article deals with the problem of testing a change in autoregressive matrices of the p-th order vector autoregressive process, VAR(p). The proposed test statistics are based on the likelihood ratio concept and are studied under the null hypothesis of no change in parameters. Their asymptotic behavior is derived under minimal moment assumptions in both cases where the time point of possible change is known a priori and is undefined. The Gumbel-type approximation of the test statistic is also developed, which previous papers on VAR(p) models do not cover.     

Hungarian Medical Students’ Knowledge About and Attitude Toward Homosexual,Bisexual, and Transsexual Individuals

ABSTRACT

Discrimination that LGBTQ individuals experience in health care settings might affect their health and intention of using health care services. However, health needs of LGBTQ patients are still inappropriately addressed in the medical curriculum. First-, third-, and fourth-year medical students (N = 569) from the four Hungarian medical universities participated in a study in 2017 to assess knowledge about homosexuality, homonegativity, and their attitude as health care professionals toward sexual minorities. We found that higher levels of knowledge about homosexuality were associated with lower levels of homonegativity, upper-grade level in university, not being religious, and having close LGBTQ acquaintances. Our results suggest that it may be necessary to introduce LGBTQ themes in the medical curricula (not only in Hungary, but also in other countries) in order to improve the knowledge and attitude of medical students and thereby improve the health care of LGBTQ individuals.     

Modernity, Traditionality, and Junior High School Attainment in Turkey

This study focuses on the impact of modernityand traditionality on junior high schoolattainment of children in Turkey. Using thenationwide Turkish Family Structure Survey, theprimary objectives are to determine whetherjunior high school attainment varies by region,city size, and by family background. Based ona sample of 2025 16 year-old adolescents, weprovide the first multivariate, nationwideanalysis of the factors associated with juniorhigh school attainment of children in Turkey. The results of the multivariate logisticregression analysis show significant variationin children's junior high school attainment byfamily background, region and urban location,which are factors that help explain persistentgender inequality in education.     

Impact of recreational physical activity on bone mineral density in middle-aged men

Physical activity is known to exert beneficial effects on general health status of young, adult and elderly populations. Exercise (aside from genetic, hormonal, nutritional and pathological factors) also influences bone mineral density (BMD). Unfortunately, the association between physical exercise and BMD in adult population is controversial. Our aim was to assess relations between recreational physical activity and BMD in middle-aged men. We performed densitometry and hormonal measurements (total testosterone, free testosterone, dehydroepiandrosterone sulfate, estradiol) in a homogenous group of 38 subjects. Among them, we distinguished 22 who had not engaged in any physical activity, and 16 who had recreationally exercised for about 10 years. Both groups did not differ in regard to hormonal status. Similarly, densitometry did not reveal any statistically significant differences in BMD between both groups of men. Upon our observation, we can hypothesize that recreational physical activity does not affect bone mineral density in middle-aged men.     

Associations Between 1980 U.S. Mortality Rates and Alternative Measures of Airborne Particle Concentration

We analyzed the 1980 U.S. vital statistics and available ambient air pollution data bases for sulfates and fine, inhalable, and total suspended particles. Using multiple regression analyses, we conducted a cross-sectional analysis of the association between various particle measures and total mortality. Results from the various analyses indicated the importance of considering particle size, composition, and source information in modeling of particle pollution health effects. Of the independent mortality predictors considered, particle exposure measures related to the respirable and/or toxic fraction of the aerosols, such as fine particles and sulfates, were most consistently and significantly associated with the reported SMSA-specific total annual mortality rates. On the other hand, particle mass measures that included coarse particles (e.g., total suspended particles and inhalable particles) were often found to be nonsignificant predictors of total mortality. Furthermore, based on the application of fine particle source apportionment, particles from industrial sources (e.g., from iron/steel emissions) and from coal combustion were suggested to be more significant contributors to human mortality than soil-derived particles.     

The odd power cauchy family of distributions: properties,regression models and applications

We study some mathematical properties of a new generator of continuous distributions with one extra parameter called the odd power Cauchy family including asymptotics, linear representation, moments, quantile and generating functions, entropies, order statistics and extreme values. We introduce two bivariate extensions of the new family. The maximum likelihood method is discussed to estimate the model parameters by means of a Monte Carlo simulation study. We define a new log-odd power Cauchy–Weibull regression model. The usefulness of the proposed models is proved empirically by means of three real data sets.