Principios para socializar y promocionar la lectura de libros científicos y docentes

Introducción: los libros científicos con fines docentes o para el aprendizaje, muestran resultados de investigación, experimentos y contenidos que permiten a los estudiantes adquirir conocimientos. En la literatura científica publicada se evidencia una carencia de publicaciones que fundamente los medios y formas que permitan realizar una correcta socialización y promoción de lectura para textos científicos y docentes. Objetivo: establecer los principios que deben regir la socialización y promoción de lectura de textos científicos con fines docentes. Métodos: el presente estudio clasifica como descriptivo con aporte práctico. Para la obtención de resultados se emplearon métodos en los niveles teórico y empírico. En el nivel teórico se emplean los métodos analítico - sintético, histórico-lógico, inductivo - deductivo y sistémico-estructural. En el nivel empírico se emplea el análisis documental clásico. Resultados: se plantean las formas y medios para la realización de una socialización y promoción de lectura de textos científicos con fines docentes tanto en el ámbito tradicional como en la web. Conclusiones: la socialización de los libros científicos y docentes debe realizarse en los medios tradicionales como en los digitales. La socialización puede realizarse a partir de tres formas: presencial, a través de un intermediario y por medio de la citación. Los medios tradicionales más empleados para la promoción y socialización de los libros científicos para la docencia son los eventos especializados. En la web se recomienda el uso de las redes sociales y académicas, los sitios web profesionales y los repositorios

PRINCIPIOS PARA SOCIALIZAR Y PROMOCIONAR LA LECTURA DE LIBROS CIENTÍFICOS Y DOCENTES

Los Libros científicos con fines docentes o para el aprendizaje, muestra resultados de investigación, experimentos y contenidos que permitan a los estudiantes adquirir conocimientos. En la literatura científica publicada se evidencia una carencia de publicaciones que fundamente los medios y formas que permitan realizar una correcta socialización y promoción de lectura para textos científicos y docentes. El presente estudio está enfocado en establecer los principios que deben regir la socialización y promoción de lectura de textos científicos con fines docentes. El presente estudio clasifica como descriptivo con aporte práctico. Para la obtención de resultados se emplearon métodos en los niveles teórico y empírico. En el nivel teórico se emplean los métodos analítico-sintético, histórico-lógico, inductivo-deductivo y sistémico-estructural. En el nivel empírico se emplea el análisis documental clásico. Se plantean las formas y medios para la realización de una socialización y promoción de lectura de textos científicos con fines docentes tanto en el ámbito tradicional como en la web

Prevalencia de los defectos congénitos renales en Pinar del Río durante el periodo 2009-2014

Introduction: renal congenital defects occur with a high frequency, where prenatal ultrasonography techniques play an important role in detecting, localizing and characterizing these abnormalities.Objectives: to describe the prevalence of renal congenital defects in Pinar del Río province during the period 2009-2014.Method: a retrospective observational study was conducted on the diagnosis of renal congenital defects in Pinar del Río province during the period 2009-2014. The sample consisted of 103 pregnant women diagnosed with a renal defect.Results: the overall prevalence rate was 23.9 per 10 000 births, 2011 showed the highest rate in the period, with 37.6 per 10 000 live births. The municipalities that occupied the first place were San Juan y Martinez with 40.6, La Palma with 32.1 and Pinar del Rio with 30.7 per 10 000 births. Among renal defects the most frequent was hydronephrosis with 46.6% of the total analyzed.Conclusions: ultrasonography is a useful technique in prenatal diagnosis, since it allows the diagnosis of fetal congenital defects of the renal system. The stable trend in relation to the number of cases diagnosed responds to the stability and the technical training of the personnel performing the ultrasonographic study in the genetic service of the province.Introducción: los defectos  congénitos  renales se presentan con una alta frecuencia, donde la ultrasonografía prenatal desempeña un papel importante al detectar, localizar y caracterizar estas anomalías.Objetivos: describir la prevalencia de los defectos congénitos renales en la provincia de Pinar del Río durante el periodo 2009-2014.Método: se realizó un estudio retrospectivo de tipo observacional sobre el diagnóstico de los defectos congénitos renales en la provincia de Pinar del Río durante el periodo 2009-2014. La muestra  estuvo constituida por 103 gestantes en las que se diagnosticó un defecto  renal.Resultados: la tasa de prevalencia  general  fue  de  23.9  por  cada 10 000 nacimientos, siendo el año 2011 el de mayor  tasa  del período, con 37.6 por cada 10 000 nacidos vivos.  Los municipios que ocuparon el primer lugar fueron San Juan y Martínez con 40.6, La Palma con 32.1 y Pinar del Río con 30.7 por cada 10 000 nacimientos. Entre los defectos renales el más frecuente fue la hidronefrosis con el 46,6% del total analizado.Conclusiones: la ecografía  es  una  técnica  útil  en  el  diagnóstico  prenatal,  pues  permite  el  diagnóstico de  defectos congénitos  fetales del sistema  renal. La   tendencia  estable  en  relación   con   la cantidad   de  casos diagnosticados  responde a la estabilidad y el entrenamiento técnico del personal que realiza el estudio ecográfico en el servicio de genética de la provincia

Photocatalytic performance of Ta2O5/BiVO4 heterojunction for hydrogen production and methylene blue photodegradation

Forming semiconductor heterojunction is promising for improved photocatalytic performance due to synergistic combination of the best properties of each material. The present study reports a simple hydrothermal strategy to form n-n heterojunction of Ta2O5 nanotubes and BiVO4 microstructures. The Ta2O5/BiVO4 heterojunctions were characterized by Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and their photocatalytic activity was evaluated by hydrogen production and photodegradation of methylene blue (MB) dye in aqueous medium under AM 1.5 G (100 mW cm-2 ) condition. The heterojunctions have optical absorption in the visible region (200-500 nm) with crystal structures defined as monoclinic for BiVO4 and orthogonal for Ta2O5. For MB photodegradation, the Ta2O5/BiVO4 obtained via hydrothermal route showed a photodegradation of 72.3%, compared to 28.3% presented by the sample produced through the mechanical mixture, with the maintenance of 86.4% of its photocatalytic performance after 3 cycles of photodegradation. For H2 production, hydrothermally prepared Ta2O5/BiVO4 generated 10.2 μmol g-1 of H2 in 3 h; while Ta2O5 nanotubes and mechanical Ta2O5/BiVO4 mixture shows 6.82 and 2.80 μmol g-1, respectively. The results suggest that Ta2O5/BiVO4 is a promising material for applications in photocatalysis, promoting sustainable energy production through hydrogen and for the treatment of effluents containing cationic dyes

Modelo para simular el efecto de la distorsión armónica en las pérdidas de transformadores monofásicos

En este trabajo se propone un método para simular transformadores monofásicos empleando el software Simulink/Matlab. El modelo está basado en los parámetros del circuito equivalente del transformador y el diseño de una carga no lineal, que provoca una distorsión armónica elevada de las corrientes, permitiendo evaluar su influencia en las pérdidas de la máquina. A través de las señales de tensión ycorrientes en los devanados del transformador, su procesamiento y el empleo de la Norma ANSI/IEEE Std. C57.110,es posible determinar las pérdidas enel transformador considerando la influencia de la distorsión armónica. El modelo se construye a partir del espectro de las señales de corriente de la carga no lineal y de los parámetros del circuito aquivalente del transformador. Los resultados de las simulaciones permiten estimar las pérdidas debido a la influencia de los armónicos, así como su influencia en la eficiencia y la cargabilidad del transformador

Biocontrol of Fusarium oxysporum by Trichoderma spp. in Aloe vera under greenhouse and field conditions

 During the last decade, an increase in the incidence of the fungus Fusarium oxysporum in aloe [Aloe vera (L.) Burm.f.] plants has been observed, reducing the national production by 14%. A study was conducted to evaluate five native strains of Trichoderma against F. oxysporum in A. vera plants, under greenhouse and field conditions. The experiment in the greenhouse consisted of evaluating 1-year-old A. vera plants, which were inoculated in the root with a suspension of 10 mL of 1×108 conidia of Trichoderma spp. This experiment consisted of six treatments with ten repetitions; five strains of Trichoderma spp. and the control (without chemical treatment). The evaluation in field was conducted for one year (2016-17) to test five strains of Trichoderma spp. and the control (without chemical treatment), under a randomized complete block design with five replications. The evaluation under greenhouse conditions showed that when A. vera plants were treated with Trichoderma asperellum, the lowest incidence (5%) of F. oxysporum was observed and plants had the highest number of leaves than the rest of the treatments with 0.9% of total solids. Under greenhouse conditions, plants inoculated with Trichoderma asperellum and T. harzianum reduced the incidence of F. oxysporum by 30% and 40%, respectively. In the field, when evaluating T. asperellum, a lower incidence (9%) of F. oxysporum was observed in A. vera plants, and the leaves showed 0.9% of total solids. The plants inoculated with T. asperellum and T. harzianum decreased the incidence of the phytopathogen by 40% and 50%, respectively.  In addition, an increase was observed in plant height, number of leaves, total solids, weight of root and leaves of A. vera with different Trichoderma species both under greenhouse and field conditions.&nbsp

Field identification of Huanglongbing (HLB) and its management alternatives

Huanglongbing or citrus greening is the most devastating disease of citrus which has caused millions in losses worldwide. However, although there are various investigations, there is still no established cure, therefore, the objective of this research was to identify HLB in the field and to know it's control alternatives, the introduction of the phytopathogen, symptoms and disease control were investigated. The generally observed symptoms of this disease are: irregular yellowing of the leaves and inverted ripening of the fruit. According to various authors, an integrated control of the disease must be carried out, such as pest control, production of seedlings in certified nurseries, adequate nutritional management and work together with various institutions and organizations, since research such as the one carried out by the University of California Riverside by the geneticist Hailing Jin can give hope for the cure or control of this phytopathogen, however there are limitations of this product and it is not yet commercialized.EObjective: The objective of this investigation is to identify huanglongbing (HLB) in the field and know their control altenatives.  Design/methodology/approach: Was investigated the introduction of the phytopathogen Candidatus Liberibacter, symptoms and control of HLB. The generally observed symptoms of this disease are irregular yellowing in the leaves and reversed ripening on the fruit.  Results: According to various authors, an integrated control of the disease must be carried out, such as pest control, production of seedlings in certified nurseries, a suitable nutrition management and working together with educational and research institutions.  Limitations on study/implications: HLB or citrus greening is the most devastating disease of citrus trees which has caused millions of dollars in losses worldwide. However, although there are several research, there is still no established cure.  Findings/conclusions: Research such as that carried out by geneticist Hailing Jin at the University of California Riverside can give hope for the cure or control of this disease, however, there are limitations to this product since it is not yet commercialized

Platinum–Vanadium Oxide Nanotube Hybrids

The present contribution reports on the features of platinum-based systems supported on vanadium oxide nanotubes. The synthesis of nanotubes was carried out using a commercial vanadium pentoxide via hydrothermal route. The nanostructured hybrid materials were prepared by wet impregnation using two different platinum precursors. The formation of platinum nanoparticles was evaluated by applying distinct reduction procedures. All nanostructured samples were essentially analysed by X-ray diffraction and transmission electron microscopy. After reduction, transmission electron microscopy also made it possible to estimate particle size distribution and mean diameter calculations. It could be seen that all reduction procedures did not affect the nanostructure of the supports and that the formation of metallic nanoparticles is quite efficient with an indistinct distribution along the nanotubes. Nevertheless, the reduction procedure determined the diameter, dispersion and shape of the metallic particles. It could be concluded that the use of H2PtCl6 is more suitable and that the use of hydrogen as reducing agent leads to a nanomaterial with unagglomerated round-shaped metallic particles with mean size of 6–7 nm