349 research outputs found

    Desarrollo organizacional en las empresas de la Region del Maule

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    296 p.La presente investigación parte con la descripción de los objetivos e hipótesis planteadas, y la metodología seguida para lograrlos. Enseguida se expone un marco teórico sobre el Desarrollo Organizacional, y se explican los modelos de comportamiento de los cuales se obtuvieron las variables utilizadas para estructurar una encuesta que se aplico a una muestra de empresas regionales, con el objeto de realizar un diagnostico organizacional. Luego se procedió a un análisis de los datos, que permitió detectar que existen algunas funciones organizacionales que deben ser mejor utilizadas, tanto en forma particular como integral, de tal manera de que las empresas regionales alcancen condiciones para enfrentarse exitosamente al cambio

    Looking at the field of “Urbanística y Ordenación del Territorio” by surveying its academic staff

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    El área de conocimiento “Urbanística y Ordenación del Territorio” (AUOT) está formada por un conjunto de profesores y profesoras vinculados en su mayoría a titulaciones universitarias de carácter tecnológico (ej. arquitectura e ingeniería de caminos). Transcurridos casi cuatro décadas desde la creación de esta área de conocimiento, el presente artículo muestra un sondeo académico a su profesorado a partir de una muestra de aproximadamente el 30% del colectivo. Los resultados obtenidos permiten explorar tendencias del colectivo académico del área de conocimiento, analizando inquietudes y visiones sobre aspectos docentes, de investigación y de promoción universitaria. Se reflexiona también sobre elementos claves que pueden ayudar al AUOT a afrontar algunos de los retos académicos del momento, incluyendo la necesidad de una mayor organización colectiva a nivel estatal.The Spanish knowledge field “Urbanística y Ordenación del Territorio” includes academics with teaching and research tasks mainly linked to technical degrees (e.g. architecture and civil engineering). Almost four decades after creating this official knowledge field, this paper presents a survey to approximately 30% of its teaching staff. The obtained results show a diagnosis and strategic reflection on the knowledge field, analyzing the academics´ concerns and visions on teaching, research, and careers expectations. It also discusses some key issues to cope with present academic challenges, including the need for a better collective coordination at the national level

    Caracterización del 4,5-diamino-1,6-dihidro-1-metil-2-metiltio-6-oxo-pirimidina con vistas a su utilización como posible ligando

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    A partir de los espectros de absorción en la zona del ultravioleta e I. R., así como del espectro de R. M, N. se ha determinado la estructura más probable para la molécula de 4,5-diamino-1,6-dihidro-1-metil-2-metiltio-6-oxo-pirimidina. Asimismo, se ha estudiado la estabilidad térmica de esta sustancia a partir de los diagramas de A. T. D. Y T. G. Por último, se ha determinado el valor de su constante ácida, que es del orden de 10-12.From the absorption spectra in the ultraviolet and infrarred regions, and from the M NR spectrum, the most probable molecular structure of the 4,5-diamino-1,6-dihidro-1-methyl-2-methylthio-6-oxo-pyrimidine has been deter mined. The thermal stability of this substance has been studied from the D. T. A. and T. G. diagrams. The apparent acid constant of the mentioned substance has also been calculated

    Estabilidad de catalizadores Ni soportados en ZrO₂ durante la hidrogenación selectiva de CO₂ hacia metano

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    En el presente trabajo se estudió el efecto del método de síntesis de soportes de ZrO₂, y el efecto de la carga metálica sobre la hidrogenación catalítica del CO₂ para la producción de metano. Los soportes utilizados fueron ZrO₂ comercial (ZrO₂-COM), y óxidos de zirconio sintetizados por los métodos de coprecipitación (ZrO₂-COP) y Sol-Gel (ZrO₂-SG). Para los catalizadores sintetizados se utilizaron cargas metálicas de níquel del 10 y 20% peso. La evaluación catalítica se llevó a cabo a presión atmosférica, en un intervalo de temperatura de 350-500°C, utilizando una relación molar estequiométrica de CO₂/H₂. Los resultados más sobresalientes se obtuvieron con los catalizadores 20%/NiZrO₂-COM y 20%/NiZrO₂-COP con conversiones de CO2 cercanas al 50% a temperaturas de 400°C. El catalizador 20%/NiZrO₂-COP presentó una buena estabilidad con una caída en la conversión de solo el 8% a un tiempo de corrida experimental de 200 horas.In this work the effect of synthesis method for ZrO₂ as support, and the effect of metal loading on the catalytic hydrogenation of CO₂ to methane production were studied. The supports were commercial ZrO₂ (ZrO₂-COM), and zirconia synthesized by the coprecipitation (ZrO₂-COP) and the Sol-Gel (ZrO₂-SG) methods. Nickel metal loading of 10 and 20 wt. % were impregnated on the synthetized catalyst. Catalytic evaluation test was performed at atmospheric pressure conditions, in a temperature range of 350-500°C, and using a stoichiometric CO₂/H₂ molar ratio. The most outstanding results were obtained with the catalysts 20%/NiZrO₂-COM and 20%/NiZrO₂-COP with CO2 conversions close to 50% at temperatures of 400°C. The catalyst 20%/NiZrO₂-COP showed a very good stability with a decrease in CO2 conversion of only 8% after 200 hours of experimental test

    Reducción de la fertilización sintética con composta y optimización del riego sobre la pudrición del tallo (Fusarium spp) del maíz

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    Maize is the most important grain crop in Mexico due to the largest area grown and as the main source of feeding nationwide; being Sinaloa de major producer. The same crop over repeated seasons has favored disease proliferation of stem and ear rot mainly attributed to Fusarium spp which represents a risk potential so that growers are warned top pay close attention to crop management. With the purpose of evaluating the effect of synthetic fertilization with compost and irrigation on maize stem and ear rot at Valle del Fuerte. Field experiments were conducted in the growing season of 2009 at INIFAP. The experiments were arranged under a split plot in randomized complete block design with three replicates. At the end of the season, it was found that fertilization or irrigation by themselves did not have any significant effect in yield and phenology variables evaluated. However, incidence on stem rot which was evaluated at 53 days after planting was that of 100%. Moreover, there were significant differences regarding severity of rotten ears when less irrigation was applied. Finally, morphological study showed that the main agent associated in maize stem rot was Fusarium verticilliodes. In contrast to that of ear rot that the main agents involved were Apergillus spp, Penicillum pinophilum, and with a higher incidence was Fusarium verticilliodes.El maíz es el cultivo agrícola de grano más importante de México por ser sembrado con mayor superficie y ser la base de la alimentación en toda la nación siendo Sinaloa el principal productor. La siembra repetitiva del cultivo efectuada a través de los años, ha favorecido la proliferación de enfermedades como la pudrición de tallos y la pudrición de mazorcas, atribuidas principalmente a Fusarium spp, las cuales representan un potencial de riesgo y han alertado al productor a poner mucha atención en el manejo del cultivo. Con el objetivo de evaluar el efecto de la fertilización sintética con composta y riego sobre la pudrición de tallos y mazorcas de maíz en el Valle del Fuerte; experimentos de campo se condujeron en el ciclo agrícola primavera-verano 2009 en el INIFAP. El experimento fue diseñado en parcelas divididas en bloques completos al azar con tres repeticiones; al final del ciclo se encontró que no hubo diferencias significativas del factor fertilización y riego respecto al rendimiento así como las variables fenológicas evaluadas. La incidencia de pudrición de tallos evaluada a los 53 días después de la siembra fue de 100%. Sin embargo, se encontraron diferencias significativas en cuanto a la severidad de mazorcas podridas donde se aplicaron menos riegos. Finalmente, el estudio morfológico mostro que el principal agente asociado en pudrición de tallos fue Fusarium verticilliodes y en cuanto a pudrición de mazorcas se detectó una mayor diversidad de agentes asociados tales como Apergillus spp, Penicillum pinophilum, y con mayor incidencia Fusarium verticilliodes

    Main properties of Al2O3 thin films deposited by magnetron sputtering of an Al2O3 ceramic target at different radio-frequency power and argon pressure and their passivation effect on p-type c-Si wafers

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    In this work, 50-nm thick Al2O3 thin films were deposited at room temperature by magnetron sputtering from an Al2O3 ceramic target at different RF power and argon pressure values. The sputtering technique could be preferred to conventional atomic layer deposition for an industrial application, owing to its simplicity, availability, and higher deposition rate. The resulting thin films were characterized by UV/Vis/NIR spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The deposited Al2O3 material was always highly transparent and amorphous in nature. It was found that the O/Al ratio is higher when the Al2O3 layer is deposited at lower RF power or higher argon pressure. Also, some argon incorporation into the films was observed at low deposition pressure. On the other hand, the performance of the previously characterized Al2O3 thin films in the passivation of 2.25-Ωcm p-type float zone c-Si wafer surfaces was evaluated by the quasi-steady-state photoconductance technique. The best effective carrier lifetime value at one-sun illumination, 0.34 ms (corresponding to a surface recombination velocity of 41 cm/s), was obtained with the 50-nm Al2O3 deposited at the higher argon pressure studied, 0.67 Pa (5.0 mTorr), with the lowest RF power studied, 150 W (corresponding to a power density of 3.3 W/cm2), and after an annealing process, in this case at 350ºC for 20 min with forming gas. It was assumed that the reduction of the surface passivation quality at higher RF power or lower argon pressure is a consequence of an increased surface damage, and, probably, to a decrease of the O/Al ratio of the Al2O3 passivation material. These assumptions were confirmed with the obtainment of a lifetime of 0.73 ms (a surface recombination velocity equal to 19 cm/s) with a simple experiment with Al2O3 deposited with progressively varied sputtering conditions started from minimal silicon surface damage conditions: 50 W (corresponding to a power density of 1.1 W/cm2) and 6.67 Pa (50 mTorr). Finally, comments about further improvement of the effective lifetime (up to 1.25 ms, corresponding to a surface recombination velocity of 11 cm/s) with preliminary experiments about the incorporation of an intrinsic hydrogenated amorphous silicon interlayer are included

    Cross-Sectional Study of the Anthropometric Profile and Nutrient Status of Elite Female Ice Hockey Players: Differences by Play Position

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    Both the characteristics of ice hockey and the environmental conditions in which it is played affect the maintenance of the player’s nutritional status and, therefore, their state of health and performance. The primary aim of this work was to examine the anthropometric profile, estimated energy expenditure, and macronutrient and micronutrient dietary intake of elite female ice hockey players by play position. As a secondary aim, their dietary intakes were compared with the recommendations. Hypotheses suggest variations in body composition based on ice hockey players’ positions, with the expectation that these athletes may not align with energy and nutrient recommendations. Fifteen elite female ice hockey players were anthropometrically measured, basal metabolic rate and total energy expenditure were estimated, a 3-day, 24 h recall questionnaire was registered, and the results were compared with the recommended dietary intake for the Spanish population. Each player’s position on the field requires an individualized physical and nutritional approach. There are no significant imbalances (p > 0.05) between energy and nutrient intake in relation to the Recommended Daily Intake (RDI); however, increasing the consumption of vegetables and seafood while reducing meat and fat intake would assist these athletes in maintaining a healthier energy balance, optimizing body composition, and aligning with nutritional parameters that are better suited to enhance physical performance.High Council for Sports (CSD), Spanish Ministry of Culture and Sport, through the NESA NETWORK “Spanish Network of Sports Care at Altitude (RADA),” Ref. 19/UPB/23Instituto de Salud Carlos III through CIBEROBN CB12/03/30038, which is cofounded by the European Regional Development Fun

    Conducta estral circanual en ovejas Pelibuey bajo condiciones áridas del noroeste de México

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    In order  to determine  the  circannual  estrus  behavior of Pelibuey  ewes  under  arid  conditions of  Northwestern Mexico(32o  NL),  22  adult  ewes  were  maintained  in  confinement  conditions  with  constant  feeding  during  one  year.  Daily,morning  and  afternoon,  the  ewe  group  was  exposed  to  one  of  three  ram  fitted  with  an  apron  to  detect estrusbehavior.  Annual  averages  of  temperature,  relative  humidity  and  temperature-humidity  index  were  25.3±8.1  ºC,33.1±10.7  %  and  72.0±8.4  units,  respectively.  Monthly  percentage  of  ewes  in  estrus  was  lower  (P0.05).  Compared  with  others  months,  a  higher  (P36  and  0.05). Comparado con el resto de los meses; un mayor (P36 y <48h) fue mayor (P<0.05) en junio y agosto. En conclusión, en condiciones áridas del noroeste de México, las ovejas Pelibuey disminuyen su actividad estral de enero a junio, y las elevadas  temperaturas ambientales de verano no son un factor que afecte la presencia de estro en dicha raza
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