Total testosterone levels are correlated to metabolic syndrome components

Introduction: Metabolic syndrome (MetS) is a constellation of interrelated risk factors of metabolic origin. Some studies suggest a possible link between low total testosterone (TT) levels and the presence of MetS.

Aim: To analyze the strength and independence of associations between TT and MetS components in non-diabetic men.

Methods: In this cross-sectional study, 143 non-diabetic men older than 40 were analyzed.

Main outcomes measure: Blood samples were collected to evaluate metabolic profile and TT levels. MetS was defined as the presence of three or more of the following characteristics: fasting blood glucose levels?≥?100?mg/dL, triglyceride?≥?150?mg/dL, HDL-c??102?cm.

Results: Mean age of the study population was 61.5?±?8.61 years old. MetS was present in 47.9% of the individuals. Thirty-four men had low TT and MetS was observed in 23 (70%) against 50 (46%) in those with normal TT (≥?300?ng/dL) (OR 4.94, p?p?=?0.03) and HDL-c (Beta: 0.19; p?=?0.04) remained significantly correlated with TT levels.

Conclusions: Low TT levels were associated with MetS diagnosis. Abdominal obesity was the MetS component independently correlated to low TT levels.     

Influence diagnostics in a multivariate normal regression model with general parameterization

Patriota and Lemonte [24] introduced a quite general multivariate normal regression model. This model considers that the mean vector and the covariance matrix share the same vector of parameters. In this paper we present some influence assessment for this model, such as the local influence, total local influence of an individual and generalized leverage which are discussed. Additionally, the normal curvatures for local influence studies are derived under some perturbation schemes.     

Personality characteristics of sexual addicts and pathological gamblers

Personality characteristics of three groups were compared: sexual addicts (N=32, 6 females, 26 males, ¯x age=36.37), pathological gamblers (N=32, 13 females, 19 males, ¯x age=46.15), and non-addicts (N=38, 13 females, 25 males, ¯x age=39.65). The sexual addict group was significantly more anxious, depressed, obsessive-compulsive and interpersonally sensitive than the non-addict control group. The sexuai addict group was significantly more depressed than the pathological gambler group. The pathological gambler group was significantly more depressed than the non-addict control group, but was not significantly more anxious, obsessive-compulsive, or interpersonally sensitive. Neither addict group scored higher on levels of sensation-seeking or self-defeating behaviors than did the non-addict control group. The results supported the view that sexual addiction can be explained as a means of coping with anxiety, depression, obsessive-compulsiveness and interpersonal sensitivity whereas pathological gambling may be used as an anti-depressant but there is no significant relationship between that addiction and the other above-mentioned personality characteristics.     

The Poisson Generalized Linear Failure Rate Model

We formulate a new cure rate survival model by assuming that the number of competing causes of the event of interest has the Poisson distribution, and the time to this event has the generalized linear failure rate distribution. A new distribution to analyze lifetime data is defined from the proposed cure rate model, and its quantile function as well as a general expansion for the moments is derived. We estimate the parameters of the model with cure rate in the presence of covariates for censored observations using maximum likelihood and derive the observed information matrix. We obtain the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes and present some ways to perform global influence analysis. The usefulness of the proposed cure rate survival model is illustrated in an application to real data.     

Peace and Conflict Resolution Organizations in Three Protracted Conflicts: Structures,Resources and Ideology

Guided by organizational and social movement theories, this study compares the structures, resource bases, ideologies, and strategies of nongovernmental organizations engaged in peace and conflict resolution (P/CROs) in three regions with extended violent conflicts: Northern Ireland, South Africa, and Israel/Palestine. Qualitative content analysis techniques are used to analyze 27 detailed case reports. We analyze the funding patterns and structural attributes of the P/CROs in our sample, with particular attention to how they obtain fiscal resources and membership in spite of the risks they may experience. We then explore the degree of formalization among P/CROs over time and, finally, we examine the ideological frames that P/CROs use and how these frames relate to their tactics. Throughout the analysis we pay attention to how the political context of each region influences P/CRO behavior.     

Signed likelihood ratio tests in the Birnbaum-Saunders regression model

The Birnbaum-Saunders regression model is becoming increasingly popular in lifetime analyses and reliability studies. In this model, the signed likelihood ratio statistic provides the basis for testing inference and construction of confidence limits for a single parameter of interest. We focus on the small sample case, where the standard normal distribution gives a poor approximation to the true distribution of the statistic. We derive three adjusted signed likelihood ratio statistics that lead to very accurate inference even for very small samples. Two empirical applications are presented.     

Multivariate elliptical models with general parameterization

In this paper we introduce a general elliptical multivariate regression model in which the mean vector and the scale matrix have parameters (or/and covariates) in common. This approach unifies several important elliptical models, such as nonlinear regressions, mixed-effects model with nonlinear fixed effects, errors-in-variables models, and so forth. We discuss maximum likelihood estimation of the model parameters and obtain the information matrix, both observed and expected. Additionally, we derived the generalized leverage as well as the normal curvatures of local influence under some perturbation schemes. An empirical application is presented for illustrative purposes.     

Non Null Asymptotic Distributions of Some Criteria in Censored Exponential Regression

In this article, we consider the class of censored exponential regression models which is very useful for modeling lifetime data. Under a sequence of Pitman alternatives, the asymptotic expansions up to order n^{? 1/2} of the non null distribution functions of the likelihood ratio, Wald, Rao score, and gradient statistics are derive in this class of models. The non null asymptotic distribution functions of these statistics are obtained for testing a composite null hypothesis in the presence of nuisance parameters. The power of all four tests, which are equivalent to first order, are compared based on these non null asymptotic expansions. Furthermore, in order to compare the finite-sample performance of these tests in this class of models, we consider Monte Carlo simulations. We also present an empirical application for illustrative purposes.     

Local power properties of some asymptotic tests in symmetric linear regression models

In this paper we obtain asymptotic expansions, up to order n^−1/2 and under a sequence of Pitman alternatives, for the nonnull distribution functions of the likelihood ratio, Wald, score and gradient test statistics in the class of symmetric linear regression models. This is a wide class of models which encompasses the t model and several other symmetric distributions with longer-than normal tails. The asymptotic distributions of all four statistics are obtained for testing a subset of regression parameters. Furthermore, in order to compare the finite-sample performance of these tests in this class of models, Monte Carlo simulations are presented. An empirical application to a real data set is considered for illustrative purposes.