Programa de prevención del consumo de drogas Saluda: evaluación de una nueva versión en adolescentes españoles

En la actualidad se han evaluado numerosas intervenciones preventivas de drogodependencias en el medio escolar. Sin embargo, en España son pocos los estudios que analizan la influencia precisa de cada uno de los componentes específicos a los programas con el fin de determinar cuáles se consideran cruciales para el cambio de conducta de consumo. El objetivo del presente estudio fue evaluar los efectos de una nueva versión del programa de prevención del consumo de drogas Saluda en la que se prescinde del componente fomento del ocio saludable y las tareas para casa. Esta versión reducida fue dirigida a una muestra de 106 escolares (44.6 % chicos) entre 14 y 17 años (M = 15.20; DT = 0.92) de un centro de Educación Secundaria. Se trata de un estudio exploratorio de tipo cuasi experimental y un diseño pre-post de un único grupo. Se realizó diferencia de proporciones mediante la prueba Z y diferencia de medias mediante la prueba T para muestras relacionadas. Los resultados muestran una reducción en el porcentaje de episodios de embriaguez, así como un efecto de mejora significativa sobre las variables protectoras del consumo. Se discuten estos hallazgos y se realizan propuestas para la mejora de futuras intervenciones.

Reducing visual deficits caused by refractive errors in school and preschool children: results of a pilot school program in the Andean region of Apurimac, Peru

Background: Refractive error is defined as the inability of the eye to bring parallel rays of light into focus on the retina, resulting in nearsightedness (myopia), farsightedness (Hyperopia) or astigmatism. Uncorrected refractive error in children is associated with increased morbidity and reduced educational opportunities. Vision screening (VS) is a method for identifying children with visual impairment or eye conditions likely to lead to visual impairment. Objective: To analyze the utility of vision screening conducted by teachers and to contribute to a better estimation of the prevalence of childhood refractive errors in Apurimac, Peru. Design: A pilot vision screening program in preschool (Group I) and elementary school children (Group II) was conducted with the participation of 26 trained teachers. Children whose visual acuity was<6/9 [20/30] (Group I) and≤6/9 (Group II) in one or both eyes, measured with the Snellen Tumbling E chart at 6 m, were referred for a comprehensive eye exam. Specificity and positive predictive value to detect refractive error were calculated against clinical examination. Program assessment with participants was conducted to evaluate outcomes and procedures. Results: A total sample of 364 children aged 3–11 were screened; 45 children were examined at Centro Oftalmológico Monseñor Enrique Pelach (COMEP) Eye Hospital. Prevalence of refractive error was 6.2% (Group I) and 6.9% (Group II); specificity of teacher vision screening was 95.8% and 93.0%, while positive predictive value was 59.1% and 47.8% for each group, respectively. Aspects highlighted to improve the program included extending training, increasing parental involvement, and helping referred children to attend the hospital. Conclusion: Prevalence of refractive error in children is significant in the region. Vision screening performed by trained teachers is a valid intervention for early detection of refractive error, including screening of preschool children. Program sustainability and improvements in education and quality of life resulting from childhood vision screening require further research.

Interplay Between Structure, Stoichiometry, and Electron Transfer Dynamics in SILAR-based Quantum Dot-Sensitized Oxides

We quantify the rate and efficiency of picosecond electron transfer (ET) from PbS nanocrystals, grown by successive ionic layer adsorption and reaction (SILAR), into a mesoporous SnO2 support. Successive SILAR deposition steps allow for stoichiometry- and size-variation of the QDs, characterized using transmission electron microscopy. Whereas for sulfur-rich (p-type) QD surfaces substantial electron trapping at the QD surface occurs, for lead-rich (n-type) QD surfaces, the QD trapping channel is suppressed and the ET efficiency is boosted. The ET efficiency increase achieved by lead-rich QD surfaces is found to be QD-size dependent, increasing linearly with QD surface area. On the other hand, ET rates are found to be independent of both QD size and surface stoichiometry, suggesting that the donor–acceptor energetics (constituting the driving force for ET) are fixed due to Fermi level pinning at the QD/oxide interface. Implications of our results for QD-sensitized solar cell design are discussed.