72 research outputs found

    Modelo de microcuásar de Población III

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    En este trabajo presentamos los resultados obtenidos en la elaboraci√≥n de un modelo completo de microcu√°sar de Poblaci√≥n III. Consideramos que la p√©rdida de masa de la estrella se debe exclusivamente al derrame de materia por desborde del l√≥bulo de Roche hacia el agujero negro. Hemos determinado que el r√©gimen de acreci√≥n para estos objetos es s√ļper-Eddington, con una intensa p√©rdida de masa del sistema en forma de vientos del disco de acreci√≥n y jets. El campo magn√©tico en el disco es supuesto toroidal y en equipartici√≥n con la densidad de energńĪŐĀa t√©rmica. Calculamos la distribuci√≥n de energńĪŐĀa espectral del disco de acreci√≥n y de la distribuci√≥n de partńĪŐĀculas relativistas en los jets, considerando un modelo lepto-hadr√≥nico.In this we present the results obtained in the elaboration of a complete Population III microquasar model. We consider that the loss of mass of the star is due exclusively to the spillage of matter due to the overflow of the Roche lobe towards the black hole. We have determined that the accretion regime for these objects is super-Eddington, with an intense loss of mass from the system in the form of accretion disk winds and jets. The magnetic field in the disk is assumed toroidal and equipartition with the density of thermal energy. We calculate the spectral energy distribution of the accretion disk and the relativistic particle distribution in the jets, considering a lepto-hadronic model.Fil: Sotomayor Checa, Pablo Omar. Provincia de Buenos Aires. Gobernaci√≥n. Comisi√≥n de Investigaciones Cient√≠ficas. Instituto Argentino de Radioastronom√≠a. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto Argentino de Radioastronom√≠a; ArgentinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernaci√≥n. Comisi√≥n de Investigaciones Cient√≠ficas. Instituto Argentino de Radioastronom√≠a. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto Argentino de Radioastronom√≠a; ArgentinaFil: Pellizza, Leonardo. Provincia de Buenos Aires. Gobernaci√≥n. Comisi√≥n de Investigaciones Cient√≠ficas. Instituto Argentino de Radioastronom√≠a. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto Argentino de Radioastronom√≠a; Argentina60 Reuni√≥n Anual de la Asociaci√≥n Argentina de Astronom√≠aMalarg√ľeArgentinaInstituto de Tecnolog√≠as en Detecci√≥n y Astropart√≠culasUNiversidad Nacional de R√≠o NegroObservatorio Pierre Auge

    Efecto de los hongos micorrícicos arbusculares en un cultivo ecológico de ají (Capsicum annuum L.) cacho de cabra

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    Mapuche farmers in southern Chile have been cultivating local ecotypes of chili pepper (Capsicum annuum L.), called locally "Cacho de cabra", for many decades. It is used to make "merkén", a condiment that is consumed locally and exported. This vegetable requires a nursery stage and can obtain nutritional benefits from symbiotic associations such as mycorrhizal fungi, achieving a better adaptation to transplanting. Arbuscular mycorrhizal fungi (AMF) are obligate biotrophes appearing in abundance in agroecosystems with conservation management. The aim of this study was to compare effectiveness of two AMF, a commercial mycorrhizal inoculant (IC, Glomus intraradices) and another native (IN, Glomus claroideum) with a control without inoculation (-I) on the production and quality of "Cacho de cabra". At 45 days after sowing (DAS) transplanting was carried out and at 90 and 216 DAS fruit quality, fungal and edaphic parameters were evaluated. The harvest was at four stages. With IN inoculation plants and with greater foliar area were obtained. Also, precocity of fruit production was observed. The harvest started 49 days earlier and fresh weight was 177% higher than that of the control. Root colonization was low, showing significant differences between IN and IC, while a large number of spores was produced in the substrate. It was concluded that inoculation with native fungi decreased transplanting stress thus accelerating the maturation stage of plants and resulting in higher and better yield quality

    Actitudes de los alumnos en educación física desde la voz de sus docentes

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    Tesis (Profesor de Educaci√≥n F√≠sica para la Ense√Īanza General B√°sica, Licenciado en Educaci√≥n)Las actitudes de los estudiantes en la clase de Educaci√≥n F√≠sica es un tema que ha sido investigado con cierta amplitud en los √ļltimos a√Īos. Sin embargo, la voz de los estudiantes en relaci√≥n con estas actitudes ha sido escasamente explorado en el campo. Este estudio tuvo como objetivo principal conocer las actitudes y pensamientos de los escolares seg√ļn sus profesores de Educaci√≥n F√≠sica de distintos establecimientos educacionales de la regi√≥n de Valpara√≠so, Chile. Se realiz√≥ un estudio de tipo cualitativo, exploratorio y descriptivo debido a que en Chile son escasos los trabajos que abordan esta tem√°tica, no existiendo ninguno en la regi√≥n de Valpara√≠so. Para identificar estos aspectos se realizaron entrevistas virtuales semi estructuradas a docentes que se desempe√Īan en el contexto p√ļblico y privado. El m√©todo de an√°lisis ocupado se basa en la Teor√≠a Fundamentada, donde se identificaron, clasificaron, separaron y relacionaron los distintos c√≥digos derivados de una categor√≠a general. Los resultados de la investigaci√≥n indican que los aspectos que afectan en las actitudes de los estudiantes son: los m√©todos de ense√Īanza, las caracter√≠sticas del docente y la organizaci√≥n de la Educaci√≥n F√≠sica. Adem√°s, las diferencias entre establecimientos p√ļblicos y privados tienen relaci√≥n con la oportunidad que tienen estos √ļltimos para generar mejores actitudes, siendo las horas curriculares la diferencia m√°s importante. Finalmente, a partir de las entrevistas, se concluy√≥ que, existen ciertos aspectos del docente que influyen favorable o desfavorablemente en las actitudes de los alumnos, dentro de los cuales se encontraron diferencias o similitudes dependiendo del g√©nero de los alumnos y del tipo de establecimiento educativo.The attitudes of students in Physical Education class is a topic that has been investigated to some extent in recent years. However, the voice of students in relation to these attitudes has been little explored in the field. The main objective of this study was to know the attitudes and thoughts of schoolchildren according to their Physical Education teachers from different educational establishments in the Valpara√≠so region, Chile. A qualitative, exploratory and descriptive study was carried out due to the fact that in Chile there are few works that address this issue, and none exist in the Valpara√≠so region. To identify these aspects, semi-structured virtual interviews were conducted with teachers who work in the public and private context. The busy analysis method is based on Grounded Theory, where the different codes derived from a general category were identified, classified, separated and related. The results of the investigation indicate that the aspects that affect the attitudes of the students are: teaching methods, the characteristics of the teacher and the organization of Physical Education. Furthermore, the differences between public and private establishments are related to the opportunity that the latter have to generate better attitudes, with the curricular hours being the most important difference. Finally, from the interviews, it was concluded that there are certain aspects of the teacher that have a favorable or unfavorable influence on the attitudes of the students, among which differences or similarities were found depending on the gender of the students and the type of educational establishment

    Prospective and Occupational Expectations Fishworkers of Ecuador to Change Matrix Production Country

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    Este artículo expone un acercamiento a la prospectiva de la movilidad ocupacional de los pescadores artesanales del Ecuador ante el cambio de la matriz productiva del país, al mejoramiento de las condiciones de trabajo en sus puertos pequeros artesanales y al apoyo al sector pesquero artesanal, a través de un análisis cuantitativo de sus aspiraciones y expectativas ocupacionales. La metodología que se consideró es el uso de datos secundarios recolectados a través de una encuesta administrada a 392 pescadores en los cinco principales puertos pesqueros artesanales del Ecuador, Puerto Aconcito y Santa Rosa de la provincia de Santa Elena, Puerto Jaramijo y San Mateo de la provincia d,e Manabí y Puerto La Poza de la Provincia de Esmeraldas. Los resultados indican que existe un componente de identidad que define las pautas sobre la ocupacionalidad de los pescadores en términos de sus aspiraciones ocupacionales y de las expectativas que los pescadores proyectan para sí mismos y a sus hijos. A un nivel subjetivo, la dimensión tradicional del oficio de pescador artesanal se ejemplifica en la importancia que tiene el trabajo como eje constituyente de la identidad de los individuos, en la permanencia en el sector, en la transmisión intergeneracional del oficio, en la creación de empresas familiares en torno a la pesca y en la negación a cambiar de ocupación.This article presents a forward-looking approach to occupational mobility of artisanal fishermen from Ecuador to changing the productive matrix of the country and the improvement of working conditions in their craft piques ports, through a quantitative analysis of their aspirations and occupational expectations. The methodology to be considered is the use of secondary data collected through a survey administered to 392 fishermen in the five major artisanal fishing ports of Ecuador, Puerto Aconcito and Santa Rosa in the province of Santa Elena, Puerto Jaramijo and the San Mateo Manabí province and Puerto La Poza of the Province of Esmeraldas. The results indicate that there is an element of identity that defines the guidelines for the ocupacionalidad of fishermen in terms of their occupational aspirations and expectations that fishermen cast for themselves and their children. At a subjective level, the traditional dimension of the office of Fish workers exemplified the importance of work as constituent axis of the identity of individuals, permanence in the sector, in the intergenerational transmission of the trade, in the creation of family businesses around fishing and the refusal to change occupations

    An Assessment of the Representation of Ecosystems in Global Protected Areas Using New Maps of World Climate Regions and World Ecosystems

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    Representation of ecosystems in protected area networks and conservation strategies is a core principle of global conservation priority setting approaches and a commitment in Aichi Target 11 of the Convention on Biological Diversity. The 2030 Sustainable Development Goals (SDGs) explicitly call for the conservation of terrestrial, freshwater, and marine ecosystems. Accurate ecosystem distribution maps are required to assess representation of ecosystems in protected areas, but standardized, high spatial resolution, and globally comprehensive ecosystem maps have heretofore been lacking. While macroscale global ecoregions maps have been used in global conservation priority setting exercises, they do not identify distinct localized ecosystems at the occurrence (patch) level, and instead describe large ecologically meaningful areas within which additional conservation planning and management are necessary. We describe a new set of maps of globally consistent climate regions and ecosystems at a much finer spatial resolution (250 m) than existing ecological regionalizations. We then describe a global gap analysis of the representation of these ecosystems in protected areas. The new map of terrestrial World Ecosystems was derived from the objective development and integration of 1) global temperature domains, 2) global moisture domains, 3) global landforms, and 4) 2015 global vegetation and land use. These new terrestrial World Ecosystems do not include either freshwater or marine ecosystems, but analog products for the freshwater and marine domains are in development. A total of 431 World Ecosystems were identified, and of these a total of 278 units were natural or semi-natural vegetation/environment combinations, including different kinds of forestlands, shrublands, grasslands, bare areas, and ice/snow regions. The remaining classes were different kinds of croplands and settlements. Of the 278 natural and semi-natural classes, 9 were not represented in global protected areas with a strict biodiversity conservation management objective (IUCN management categories I-IV), and an additional 206 were less than 8.5% protected (half way to the 17% Aichi Target 11 goal). Forty four classes were between 8.5% and 17% protected (more than half way towards the Aichi 17% target), and only 19 classes exceeded the 17% Aichi target. However, when all protected areas (IUCN management categories I-VI plus protected areas with no IUCN designation) were included in a separate global gap analysis, representation of ecosystems increases substantially, with a third of the ecosystems exceeding the 17% Aichi target, and another third between 8.5% and 17%. The overall protection (representation) of global ecosystems in protected areas is considerably less when assessed using only strictly conserved protected areas, and more if all protected areas are included in the analysis. Protected area effectiveness should be included in further evaluations of global ecosystem protection. The ecosystems with the highest representation in protected areas were often bare or sparsely vegetated and found in inhospitable environments (e.g. cold mountains, deserts), and the eight most protected ecosystems were all snow and ice ecosystems. In addition to the global gap analysis of World Ecosystems in protected areas, we report on the representation results for the ecosystems in each biogeographic realm (Neotropical, Nearctic, Afrotropical, Palearctic, Indomalayan, Australasian, and Oceania)

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60‚ÄČ109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‚ÄėTypical‚Äô symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (‚ȧ‚ÄČ18 years: 69, 48, 23; 85%), older adults (‚Č•‚ÄČ70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P‚ÄČ<‚ÄČ0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

    Ubicación estratégica gerencia gestión de materiales Lan Airlines

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    Tesis (Ingeniero en Administraci√≥n de Empresas)La Gerencia de Gesti√≥n de Materiales de LAN Airlines S.A. presta servicios, principalmente a gerencias de mantenimiento de aeronaves. Uno de los proyectos que esta gerencia est√° analizando es la ubicaci√≥n estrat√©gica que debe tener, y se han detectado algunos problemas, que podr√≠an traer complicaciones al nivel de servicio. Estos son principalmente: Dobles fletes, y una relaci√≥n comprador - proveedor no eficiente. El objetivo del presente estudio es examinar la utilidad de estas t√©cnicas de toma de decisi√≥n y de qu√© forma se puede definir la ubicaci√≥n estrat√©gica de la Gerencia de Gesti√≥n de Materiales, para lograr la optimizaci√≥n de flujos de informaci√≥n y materiales en busca de minimizar los costos y hacer eficiente la operaci√≥n. Se describe en el marco te√≥rico temas de log√≠stica, investigaci√≥n de operaciones y m√©todos de decisi√≥n multicriterio necesarios para introducir al tema de ubicaci√≥n de empresas. El m√©todo que se utilizar√° es el Modelo de Proceso de An√°lisis Jer√°rquico (AHP), ya que permite de manera eficiente organizar la informaci√≥n, descomponerla y analizarla por partes y luego unir las soluciones en una conclusi√≥n. Los criterios que se tomaron en cuenta son: Costo de Inventario, Mano de obra, Cercan√≠a a los clientes, Tiempos de Transporte y Zonas Francas. Las alternativas propuestas son: Santiago, Buenos Aires, Miami y Lima. En el cap√≠tulo aplicaci√≥n del AHP se desarrolla el modelo seg√ļn el √°rbol de jerarqu√≠as de los criterios y las alternativas del problema. En el cap√≠tulo Resultados del M√©todo se presentan las matrices con que se obtienen las preferencias de selecci√≥n de localizaci√≥n. En el dise√Īo de la metodolog√≠a se describe el esquema del AHP y el an√°lisis del inventario operacional que es el factor que servir√° para el estudio de los criterios. La suma del costo promedio anual del inventario operacional de los cuatro almacenes es de MUS14.783,01.EncomparacioňänalcostopromediodeinventariooperacionalquetendrńĪňäaquetenercadaCentrodeDistribucioňänsumadoalinventariomńĪňänimoatenerenlasotrasfilialesentregalossiguientesdatos:SantiagoMUS14.783,01. En comparaci√≥n al costo promedio de inventario operacional que tendr√≠a que tener cada Centro de Distribuci√≥n sumado al inventario m√≠nimo a tener en las otras filiales entrega los siguientes datos: Santiago MUS15.286,69, Miami MUS16.969,99,BuenosAiresMUS16.969,99, Buenos Aires MUS17.286,55 y para Lima de MUS$17.382,03. Por lo tanto, se puede concluir que, bajo el concepto de costo promedio de inventario, es conveniente trabajar con el modelo actual. Luego de la aplicaci√≥n del m√©todo se obtuvo el vector de prioridad global de las alternativas. Seg√ļn estos resultados mostrados a continuaci√≥n, se concluye que la alternativa de Santiago es preferida a las otras alternativas. La alternativa que la sigue, es Miami. Muy lejos de estas alternativas se encuentra Buenos Aires y Lima, y esto se debe principalmente a que no cumple con los criterios de Tiempo de Transporte, Zonas Francas y Mano de Obra

    Competencia pol√≠tica, empleo burocr√°tico y eficiencia en la provisi√≥n de bienes p√ļblicos: Un modelo formal

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    Este art√≠culo analiza el efecto que tiene la competencia pol√≠tica sobre el desempe√Īo gubernamental, en el sentido de la eficiencia del nivel de empleo burocr√°tico y en la provisi√≥n de bienes p√ļblicos. En contraste con otros argumentos que relacionan positivamente la competencia pol√≠tica y la eficiencia del gubernamental, el principal resultado muestra que en cualquier equilibrio pol√≠tico-econ√≥mico la competencia pol√≠tica genera incentivos para un nivel de empleo burocr√°tico excesivo y una provisi√≥n ineficiente de bienes p√ļblicos. En el art√≠culo presenta un modelo espacial de competencia pol√≠tica con dos partidos donde el partido incumbente ofrece empleo burocr√°tico para proveer bienes p√ļblicos. Los partidos compiten para maximizar el n√ļmero de partidarios dentro de la ciudadan√≠a y la oferta de empleo burocr√°tico puede ser utilizada como patronazgo lo cual incentiva el crecimiento excesivo de empleo burocr√°tico
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