Foreword to the special virtual issue on Modern approaches and tools for teaching crystallography.

A compilation of articles with a strong teaching element published since 2018 is presented alongside an overview of the articles in the special issue on this topic.

Further definition on the multiple partner choice arena: a potential animal model for the study of premature ejaculation.

INTRODUCTION: The multiple partner choice arena (MPCA) is an experimental setup in which male rats display a significant shortening of ejaculation latency, which is the main characteristic of premature ejaculation (PE) in men. Thus, the MPCA is a potential animal model for PE. AIM: In this study, we further analyze whether the features of the MPCA satisfy the validity criteria for it to be considered an animal model as well as the possible participation of the serotoninergic system in the faster ejaculation exhibited by male rats in the MPCA. METHODS: In Experiment 1, male rats were tested in a standard arena to assess their sexual behavior, then were assessed 1 week later in the MPCA. Another group was first tested in the MPCA, then in a standard arena. In Experiment 2, male rats divided into two groups were treated daily with WAY-100635 (5-HT(1A) antagonist) or vehicle for 15 days. In each group, half of the subjects were tested in a standard arena and half were tested in the MPCA on days 1, 8, and 15 of treatment. MAIN OUTCOME MEASURES: Number of intromissions and intromission and ejaculation latencies were the main outcome measures. RESULTS: In Experiment 1, males tested in the MPCA ejaculated significantly faster, regardless of the order in which they were evaluated in both arenas. In Experiment 2, the administration of WAY-100635 increased intromission and ejaculation latencies, and the number of intromissions in the MPCA. CONCLUSIONS: The results obtained in the MPCA support its use as an animal model for PE evaluation.

Propiedades psicométricas del Cuestionario de Condiciones de Trabajo (qCT) en una muestra multiocupacional venezolana / Psychometric properties of the Questionnaire of Working Conditions (qCT) in a Multi-occupational Venezuelan Sample

En el presente estudio se determinó la validez de constructo y las propiedades psicométricas del Cuestionario de Condiciones de Trabajo (qCT), de Blanch, Sahagún y Cervantes (2010), en una muestra multiocupacional venezolana, que evalúa los componentes psicosociales del entorno laboral que afectan salud y rendimiento, siguiendo el método de dos pasos de Anderson y Gerbing (1988) y Boomsma (2000). Se determinaron tres modelos factoriales posibles (paso 1); se depuraron estadísticamente hasta obtener un modelo final (paso 2), que coincidió con el modelo teórico original. Adicionalmente se verificó la validez de criterio convergente del qCT con un indicador de bienestar psicológico general, encontrando que el modelo con mayor correlación con este indicador coincide con aquel de mejor ajuste obtenido en el paso 2. Se sugiere la estandarización de ítems, mediante la reducción de amplitud de respuesta en la escala Likert y el cálculo del puntaje en los factores por medio del método ponderado.

This research work aimed to establish the number of factor models underlying the Working Conditions Questionnaire (Blanch, Sahagún and Cervantes, 2010) that assesses the psychosocial components of the environment at work place. Its methodological justification is focused on the accuracy of the instrument, to clarify psychosocial aspects of work that affect employees' health and performance; as well as to determine the psychometric properties of the instrument in the country. The 2-phase method of Anderson , Gerbing and Boomsma was used to solve the error of factorial indeterminacy Exploratory Factor Analysis, and evaluate level adjustment models. Finally, two factor models were determined viable, the theoretical model obtained the highest number of indicators in the confirmatory stage setting and a good relation with the psychological well-being indicator. It is suggested items standardization, calculating weighted score obtained from confirmed factors, and reducing the scale response.