Influence of pH on properties of ZnS thin films deposited on SiO2 substrate by chemical bath deposition

Artículo Publicado en Revista indexadaThis work focuses on the study of zinc sulfide (ZnS) thin films prepared by chemical bath deposition. The effect of the pH ranging from 10.0 to 10.75 on quality of ZnS thin films on SiO2 substrate is investigated. The effect of pH on the surface showed that the variation of pH has a significant effect on the morphology of the ZnS thin films. The sample with pH value of 10.50 was uniform, free of agglomerates with band gap energy about 3.67 eV. The resistivity of ZnS thin films on SiO2 substrate with different pH value were about 107 Ω cm.DGAPA-PAPIIT IN108613-2 - PROYECTO UNA

Mineralization of human premolar occlusal fissures: a quantitative histochemical microanalysis

The mechanisms of cariogenesis in occlusal fissures remain elusive because of limited information about fissure structure and wall mineralization. The purpose of the present study was to determine the correlation between morphological patterns in occlusal fissures in human premolars and quantitative histochemical patterns of mineralization in the walls of these formations. We used scanning electron microscopy and quantitative X-ray microanalysis with the peak-tolocal background ratio method and microcrystalline calcium salts as standards. We distinguished three morphological patterns of fissures in scanning electron microscopic images. The wall of the fissures was less mineralized than the control enamel in all three types of fissures. Because the fissure walls are hypomineralized, we suggest that practicing dentists should take into account the degree of mineralization when they are preparing the fissures for the application of sealant.This work was partially supported by the Ministerio de Educación y Cultura (PB97-0840) and the Agencia Española de Cooperación Internacional (AECI)

Bibliometric analysis of scientific production in environmental accounting

La literatura académica tiene décadas de abordar el concepto y contexto que engloba la contabilidad ambiental, con lo cual, exige un monitoreo riguroso y continuo de su evidencia científica. El objetivo del manuscrito fue analizar la producción científica mundial relacionada con la contabilidad medioambiental a fin de evaluar el contexto y el comportamiento de sus contribuciones, viabilizando así la planificación y ejecución de futuras investigaciones. Se realizó una búsqueda bibliográfica utilizando la base de datos de Web of Science. Se identificaron un total de 299 documentos publicados, la modalidad de publicación, los países mayormente productivos, las revistas científicas, las instituciones más productivas e indicadores de citación e impacto. Se encontró que Australia ocupa el primer lugar con 50 documentos publicados. A su vez, se identifica a Victoria University Wellington como la institución que presenta mayor liderazgo respecto al número de publicaciones. El número total de citas de todas las publicaciones fue de 11.411. Se puede concluir que existe un crecimiento exponencial de la producción científica, siendo la última década la de mayor producción, destacando países como Australia, Estados Unidos e Inglaterra, donde las publicaciones tuvieron un impacto relativamente alto al estar alojados en revistas de cuartil (Q1 y Q2) del Scimago Journal Rank.Academic literature has decades of addressing the concept and context that encompasses environmental accounting, thus requiring rigorous and continuous monitoring of its scientific evidence. The aim of the manuscript was to analyze the global scientific production related to environmental accounting in order to assess the context and behavior of its contributions, thus enabling the planning and execution of future research. A literature search was conducted using the Web of Science database. A total of 299 published documents were identified, as well as the publication modality, the most productive countries, the scientific journals, the most productive institutions, and citation and impact indicators. Australia was found to occupy the first place with 50 published papers. In turn, Victoria University Wellington was identified as the institution with the highest number of publications. The total number of citations of all publications was 11,411. It can be concluded that there is an exponential growth of scientific production, being the last decade the one with the highest production, highlighting countries such as Australia, the United States and England, where publications had a relatively high impact as they are housed in quartile journals (Q1 and Q2) of the Scimago Journal Rank.A literatura acadêmica tem décadas para abordar o conceito e o contexto que engloba a contabilidade ambiental, exigindo assim um rigoroso e contínuo monitoramento de suas evidências científicas. O objetivo do manuscrito era analisar a produção científica global relacionada à contabilidade ambiental a fim de avaliar o contexto e o desempenho de suas contribuições, possibilitando assim o planejamento e a execução de pesquisas futuras. Foi realizada uma pesquisa bibliográfica utilizando o banco de dados da Web of Science. Foram identificados 299 artigos publicados, o modo de publicação, os países mais produtivos, as revistas mais produtivas, as instituições mais produtivas e os indicadores de citação e impacto. A Austrália ficou em primeiro lugar com 50 artigos publicados. Por sua vez, a Victoria University Wellington foi identificada como a instituição líder em termos de número de publicações. O número total de citações de todas as publicações foi de 11.411. Pode-se concluir que há um crescimento exponencial na produção científica, sendo a última década a de maior produção, destacando-se países como Austrália, Estados Unidos e Inglaterra, onde as publicações tiveram um impacto relativamente alto por estarem alojadas em periódicos quartis (Q1 e Q2) do Scimago Journal Rank

Prácticas de lectura en estudiantes de educación media : La lectura interdisciplinar e intertextual como aproximación a la cultura académica universitaria

En esta tesis de grado, se describen las características que adquiere las prácticas de lectura (PL) de estudiantes de educación media, a partir de una propuesta didáctica interdisciplinar e intertextual, como aproximación a la cultura académica universitaria. Para ello, se abordaron tres aspectos considerados importantes. El primero, la cultura académica universitaria (CAU), desde su canon y pre requisitos relacionados con el desarrollo de las prácticas lectoras en los estudiantes al ingresar a ésta cultura, para lograr las comprensiones disciplinares en sus estudios. El segundo, la necesidad de abordar la lectura académica como práctica discursiva en la educación media, a partir de las necesidades de la CAU. Por último, la importancia de abordar esta práctica, desde un enfoque interdisciplinar e intertextual, para posibilitar comprensiones contextual izadas en los estudiantes. Así, se desarrolló una secuencia didáctica en lectura para la educación media, que permitiera una aproximación a la CAU. En la descripción de estas características de la PL, se utilizó un enfoque metodológico holístico- inductivo-ideográfíco desde la sistematización y el análisis de contenido, en donde, se construyeron categorías de análisis deductivas e inductivas, de las cuales se obtuvieron como resultados más relevantes, la comprensión del texto académico y aprendizajes interdisciplinares en las estudiantes.In this thesis, the characteristics achieved by the reading practice (PL) of middle school students are described, based on an interdisciplinary and intertextual didactic proposal, as an approximation to the university academic culture. For this, three aspects considered important had been addressed. The first, the academic university culture (CAU), from its canon and pre requircments related to the development of reading practice in students to enter this culture, to achieve the disciplinary understandings in their studies. The second, the need to approach academic reading as a discursive practice in secondary education, based on the needs of the CAU. Finally, the importance of addressing this practice, from an interdisciplinary and intertextual approach, to enable contextualized understandings in students. Thus, a didactic sequence was developed in reading for secondary education, which allowed an approximation to the CAU. In the description of these features of PL, a holistic-inductive-idiographic methodological approach was used ffom the systematization and the content analysis, where categories of deductive and inductive analysis were constructed, ffom which they were obtained as more relevant results, comprehension of academic text and interdisciplinary learning in students.Magíster en EducaciónMaestrí

ESTUDIO DE PARÁMETROS MEDIANTE SIMULACIÓN PARA OPTIMIZACIÓN DE UN MESFET DE ZNO (STUDY OF SIMULATING PARAMETERS TO OPTIMIZE A MESFET OF ZNO)

Resumen En este trabajo se realiza un estudio de los parámetros principales que afectan el desempeño de una unión rectificadora Schottky que es la base del control del canal en un MESFET de ZnO. Los parámetros estudiados son el grosor a, el ancho de compuerta y las distancias de separación entre la compuerta y la fuente , y entre la compuerta y el drenaje . Así como diferentes metales para el contacto rectificador de compuerta, del análisis se encuentra que la estructura de Paladio de 500nm de y con un grosor y una concentración de da , la mejor rectificación y valores de resistencia serie de 0.076 ohms que son característicos de este material. Palabras Clave: Diseño de dispositivos, física de semiconductores, microelectrónica. Abstract In this work is realized a study of the main parameters and the effects of the behavior of a rectifier Schottky junction that is used as a base to channel control of a ZnO MESFET. The parameters considered are thickness a, gate width , and the lengths of the source at gate and gate at drain . Different metals are considered like rectifier contact of the gate, results of the analysis shown that the Palladium structure of 500nm of and 500nm= with thickness and a free carrier density of yield , the best rectification and values of serial resistance of 0.076 Ohms are typical of this material. Keywords: Device design, microelectronic, physics of semiconductors

White wine processing by UHPH without SO2. Elimination of microbial populations and effect in oxidative enzymes, colloidal stability and sensory quality

The use of UHPH sterilization in the absence of SO2 has been used to eliminate wild microorganisms and inactivate oxidative enzymes. A white must of the Muscat of Alexandria grape variety was continuously processed by UHPH at 300 MPa (inlet temperature: 23–25 °C). The initial microbial load of the settled must was 4-log CFU/mL for both yeast and moulds, and slightly lower for bacteria. After UHPH processing, no microorganisms were detected in 1 mL. UHPH musts remain without fermentative activity for more than 60 days.Postprint (published version

Mortality and risk of tuberculosis among people living with HIV in whom TB was initially ruled out

Tuberculosis (TB) misdiagnosis remains a public health concern, especially among people living with HIV (PLHIV), given the high mortality associated with missed TB diagnoses. The main objective of this study was to describe the\xC2\xA0all-cause mortality, TB incidence rates and their\xC2\xA0associated risk factors in a cohort of PLHIV with presumptive TB in whom TB was initially ruled out. We retrospectively followed a cohort of PLHIV with presumptive TB over a 2\xC2\xA0year-period in a rural district in Southern Mozambique. During the study period 382 PLHIV were followed-up. Mortality rate was 6.8/100 person-years (PYs) (95% CI 5.2-9.2) and TB incidence rate was 5.4/100 PYs (95% CI 3.9-7.5). Thirty-six percent of deaths and 43% of TB incident cases occurred in the first 12\xC2\xA0months of the follow up. Mortality and TB incidence rates in the 2-year period after TB was initially ruled out was very high. The\xC2\xA0TB diagnostic work-up and linkage to HIV\xC2\xA0care should be strengthened to decrease TB burden and all-cause mortality among PLHIV with presumptive TB