The motor systems that produce behavioral movements are among the primary targets for the action of steroid hormones, including androgens. Androgens such as testosterone bind to androgen receptors (AR) to induce physiological changes in the size, strength, and energetic capacity of skeletal muscles, which can directly influence the performance of behaviors in which those muscles are used. Because tissues differentially express AR, resulting in tissue-specific sensitivity to androgens, AR expression may be a major target of selection for the evolution of behavior. Anolis lizards (i.e., anoles) provide a robust system for the study of androgen-regulated traits, including the behavioral traits that facilitate social display and locomotion. In this study, we examined six anole species that demonstrate significant variation in the behavioral use of the forelimbs to measure the proportion of myonuclei in the bicep muscles that express AR. Using phylogenetic comparative analyses, we found that species with a greater proportion of nuclei positive for AR expression in the biceps exhibited greater frequencies of locomotor movements and pushup displays. These results suggest that AR expression in skeletal muscles may influence the evolution of androgen-regulated behaviors in this group.
Background: A high rate of student abuse has been reported in various studies; however, few studies substantiate the seriousness of the issue in Latin American contexts. This study aimed to characterize the abuse of university students in five Latin American countries and its association with student satisfaction. Methods: An analytical transversal study was conducted, in which 2,141 undergraduate students from Paraguay, Ecuador, Colombia, Venezuela, and Panama were surveyed. A validated questionnaire was applied to evaluate four types of abuse (Cronbach's Alpha: 0.90): psychological, physical, academic, and sexual. In addition, students’ perception of satisfaction of four items in the university environment (Cronbach's Alpha: 0.85) was also analyzed. Results: It was found that the older students were, the more dissatisfied they were with “logistics” (aPR: 1.02; 95% CI: 1.00-1.04; p-value; 0.014) and the top-third segment of those who perceived “sexual abuse” were more dissatisfied with the teaching provided by their universities (aPR: 1.23; 95% CI: 1.00-1.52; p-value: 0.048). Moreover, those who were most dissatisfied with the agreements were part of the top-third segment of those who perceived sexual abuse (aPR: 1.16; 95% CI: 1.03-1.32; p-value: 0.016) and those in the country of Panama were less dissatisfied with “agreements” (RPa: 0.70; 95% CI: 0.66-0.073; p-value<0.001). The countries of Colombia (aPR: 0.08; IC95%: 0.01-0.59; p-value: 0.014) and Panama (aPR: 0.57; 95% CI: 0.52-0.64; p-value<0.001) were less dissatisfied with investigation programs. Conclusions: The perception of ‘sexual abuse’ was the only risk factor statistically associated with dissatisfaction with teaching and agreements.
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