401 research outputs found

    Can output explain the predictability and volatility of stock returns?.

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    This paper examines whether a general equilibrium asset pricing model can explain two important empirical regularities of asset returns, extensively documented in the literature: (i) returns can be predicted by a set of macro variables, and (ii) returns are very volatile. We derive a closed-form solution for the equilibrium asset pricing model that relates asset returns to output by using an approximate method proposed by Campbell (Am. Econ. Rev. 83 (1993) 487) and Restoy and Weil (W.P. NBER, No. 6611 (1998)). We obtain evidence on eight OECD economies using both quarterly and annual observations. Equilibrium models seem to fin fewer difficultie in explaining the volatility of returns than their predictability for general output processes. In the case of the US, the observed predictability and volatility of asset returns, for annual frequencies, are broadly compatible with the predictions of equilibrium models for a reasonableGeneralized isoelastic preferences; Asset returns; Real activity; Volatility;

    A general equilibrium approach to the stock returns and real activity relationship

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    This paper brings together two separate and important topics in finance: the predictability of aggregated stock returns and the intertemporal asset pricing models. We present empirical evidence about the predictability of stock returns with a sample of OECD economies and investigate whether such evidence is consistent with a simple general equilibrium model. Our framework allow us to formalize the extensively documented empirical relationship between asset returns and real activity. The principal parameters in this relationship are the relative risk aversion and the elasticity of intertemporal substitution for the first moment of the returns and only the elasticity of substitution for the second moments. Except for the United States annual case, the puzzle of volatility remains in our model

    CONSTRUCCIÓN Y PROGRAMACIÓN DE SENSORES DE BAJO COSTO COMPATIBLES CON EL KIT DE ROBÓTICA LEGO MINDSTORMS NXT

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    El presente artículo expone de forma breve los conceptos claves relacionados con la implementación y construcción de sensores de bajo costo para el kit de robótica LEGO Mindstorms NXT. El kit principalmente consta de un bloque inteligente con cuatro puertos de entrada que permiten capturar la información que proviene de distintos sensores. Estos se pueden programar a partir de software como LeJOS, BRICXCC y LabVIEW entre otros. En este documento se muestra el proceso necesario para el diseño e implementación de librerías en estos lenguajes, con el fin  de poner en funcionamiento los sensores de bajo costo construidos, y de esta manera brindar pautas y herramientas necesarias para que el usuario y estudiante pueda implementar sus propios S.B.C1. Se exponen puntos claves en cuanto a la conexión y adaptación de los S.B.C al NXT y sus diferencias con respecto a los sensores originales del kit y  los homologados

    8-bit softcore microprocessor with dual accumulator designed to be used in FPGA

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    Context: This paper is presents the design and implementation of an 8-bit softcore RISC microprocessor able to be run on space-optimized FPGA, in order to be used for embedded applications. Method: The design of this microprocessor was developed in Verilog hardware description language and can be implemented in FPGA from different manufacturers; therefore, the user has only to define the input and output ports according to the type of FPGA. This is an accumulator-type processor, but it has two different accumulators that can be used as pointers for indirect addressing. The processor is Harvard with a RAM of 8x256 bits, and a ROM that can be resized from 17x252 bits to 17x8K bits. Additionally, it has one 8-bit input port, one 8-bit output port, and one 8-bit address port, which means that the processor can address more than 256 8-bit output ports/devices. The same applies for input ports. Results: The developed processor, named “ZA-SUA,” was compared with PICOBLAZE softcore and other three similar processors of free distribution in the Web, and some improvements over those were found. Criteria such as the Flip Flops used, occupied LUTs, Slices in use, and maximum delay of each processor were analyzed, all these results were obtained from the implementation of the processors in the Xilinx FPGAs. Conclusions: The designed architecture is composed by two accumulators, which can be used either as source or destination for the operation of the ALU. This fact gives some flexibility to the design, doing it better than a single-accumulator processor, and getting it closer to the register-based processors

    8-bit softcore microprocessor with dual accumulator designed to be used in FPGA

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    Context: This paper is presents the design and implementation of an 8-bit softcore RISC microprocessor able to be run on space-optimized FPGA, in order to be used for embedded applications.Method: The design of this microprocessor was developed in Verilog hardware description language and can be implemented in FPGA from different manufacturers; therefore, the user has only to define the input and output ports according to the type of FPGA. This is an accumulator-type processor, but it has two different accumulators that can be used as pointers for indirect addressing. The processor is Harvard with a RAM of 8x256 bits, and a ROM that can be resized from 17x252 bits to 17x8K bits. Additionally, it has one 8-bit input port, one 8-bit output port, and one 8-bit address port, which means that the processor can address more than 256 8-bit output ports/devices. The same applies for input ports.Results: The developed processor, named “ZA-SUA,” was compared with PICOBLAZE softcore and other three similar processors of free distribution in the Web, and some improvements over those were found. Criteria such as the Flip Flops used, occupied LUTs, Slices in use, and maximum delay of each processor were analyzed, all these results were obtained from the implementation of the processors in the Xilinx FPGAs.Conclusions: The designed architecture is composed by two accumulators, which can be used either as source or destination for the operation of the ALU. This fact gives some flexibility to the design, doing it better than a single-accumulator processor, and getting it closer to the register-based processors

    La enseñanza del Derecho del Trabajo a través del método jurídico: análisis normativo, judicial y doctrinal

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    La presente memoria tiene por objeto exponer las principales conclusiones a las que se ha llegado en relación con la materia de análisis concerniente a los instrumentos docentes que resultan más adecuados en orden a alcanzar con éxito los objetivos relativos a la enseñanza por competencias y el aprendizaje autónomo que permitan al alumno afrontar con éxito el ejercicio de las profesiones para las que le capacita su titulación. El análisis se lleva a cabo en relación con la asignatura Derecho del Trabajo, que constituye una materia central en el Área de Conocimiento del Derecho del Trabajo y de la Seguridad Social, impartida en varias titulaciones universitarias, principalmente, en los estudios de Derecho, DADE, Relaciones Laborales y Recursos Humanos, pero también en los Grados de Turismo, Criminología o Trabajo Social. En este contexto, y partiendo de la base de la importancia y necesidad de diseñar un tipo de formación (y evaluación) por competencias, el equipo investigador de esta red ha trazado el diseño de dicha asignatura a través del recurso a tres herramientas básicas del método jurídico: el análisis de las normas jurídicas, la interpretación judicial de las mismas, y la exégesis efectuada por parte de la doctrina científica

    D-chiro-inositol prevents memory deficits in the 3xTg mouse model of Alzheimer’s disease in a sex-dependent manner.

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    Subida por la tutora, a petición de Beatriz Pacheco Sánchez.Alzheimer’s disease (AD) is recognized as an age-related neurodegenerative disorder, characterized by the aggregation and deposition of amyloid-β (Aβ) in plaques and neurofibrillary tangles (NFTs) composed of aggregates of hyperphosphorylated tau, a microtubule-associated protein. Sporadic AD, the most prevalent form of the disease, has been proposed to be associated with alterations on insulin signaling. Insulin regulates a series of cognitive processes, such as learning and memory formation and emerging data demonstrate pivotal roles for brain insulin resistance and insulin deficiency as mediators of neurodegeneration, particularly in AD. The present study describes the effect of oral dietary administration of D-Chiro-inositol (DCI), an inositol used against insulin resistance, on the occurrence of the cognitive impairment of 3xTg-AD mice. This so called “triple‐ transgenic mice” model mimics many critical aspects of AD neuropathology. To this end, we analysed the effects of daily oral administration DCI 200 mg/Kg/day in male and female 3xTg and WT mice of 9 and 3 months of age. In addition to the evaluation of memory on the Novel Object Recognition, both the locomotion and time in the centre zone of an open field (OF), and the locomotion and anxiety-like behaviour in the elevated plus maze (EPM) test, were monitored. Our results showed that the exploration time of the new object was remarkably higher in the male 3xTg-DCI group when compared to those obtained from the 3xTg-vehicle and WT- vehicle groups at a middle and older age (3 and 9 months). When the center exploration time was analyzed in OPF test, three-way ANOVA showed an effect of the genotype in middle-aged animals. In the EPM test, only 9 months old 3xtg-DCI females were more prone to explore the open-arm, suggesting DCI decreases anxiety levels related to AD. In conclusion, our study suggest that DCI prevents and improves in a sex-dependent manner, the cognitive impairment associated to AD.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Manual de higiene postural para operadores de medios tecnológicos en una empresa de seguridad privada de Bogotá.

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    Los operadores de pantallas de visualización de datos son trabajadores expuestos a una elevada carga física de trabajo estática derivada del mantenimiento por largos periodos de tiempo de posturas sedentes en el trabajo. Objetivo: Diseñar un manual de higiene postural para operadores de medios tecnológicos en empresas de seguridad privada de Bogotá. Metodología: Evaluación de la carga física por medio del método RULA y de los síntomas musculo esqueléticos por medio del Cuestionario Nórdico de Kourinka. Con sus resultados diseñar un manual de higiene postural para los operadores de pantallas de visualización de datos. Resultados: Calificaciones altas a nivel de miembros superiores que suponen una importante carga física en este segmento corporal, así como en la región dorsal lumbar. Resultados que se relacionan con los datos del cuestionario de Kourinka que muestra molestias en estos segmentos corporales. Se desarrolla un manual conforme a los resultados de las evaluaciones adelantadas. Conclusiones: Se requiere un estudio más detallado de las condiciones de carga física; es deseable realizar seguimiento a los trabajadores para evitar la aparición de trastornos musculo esqueléticos crónicos

    Caracterización química y cuantificación del rendimiento de extracción de pigmento en siete accesiones mexicanas de Bixa orellana

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    Achiote (Bixa orellana) is a plant used for obtaining a natural dye rich on carotenoids (mainly bixin and norbixin); it is also the plant species with the highest content of tocotrienols in nature. In the present work, the pigment extraction yield of seven Mexican accessions of Bixa orellana was quantified. Also color parameters and content of tocotrienols, tocopherols, norbixin, bixin, total phenolic compounds and antioxidant capacity were evaluated in the corresponding annatto extracts. The highest percentage of pigment extraction yield was obtained with KOH (4.84%). Accessions 43 (L*= 4.01 ± 0.79, C*= 7.33 ± 1.07, h= 25.76 ± 6.35) and 50 (L*= 3.17 ± 0.64, C*= 6.81 ± 0.53, h= 26.41 ± 4.41) had the lowest color values, meaning these accessions had a darker and redder color. Four accessions showed the highest content of bixin: accession 48 (3.1%), 45 (2.6%) 43 (2.4%) and 47 (2.2%). Accession 50 had showed the highest content of total phenolic compounds and of tocotrienols (T3), mainly the isoform δ-T3 (5.03 ± 0.64 mg g−1 Seed Dry Weight), as well as the highest antioxidant capacity.El achiote (Bixa orellana) es una planta utilizada para obtener un colorante natural rico en carotenoides (principalmente bixina y norbixina); además, es la especie vegetal con el mayor contenido de tocotrienoles. En este trabajo, se determinó el rendimiento de extracción de pigmento de siete accesiones mexicanas de Bixa orellana. También se evaluaron los parámetros de color y el contenido de tocotrienoles, tocoferoles, norbixina, bixina, compuestos fenólicos totales y la capacidad antioxidante en extractos de annato. El mayor porcentaje de rendimiento de extracción de pigmento fue obtenido con KOH (4.847905%). Las accesiones 43 (L*= 4.01 ± 0.79, C*= 7.33 ± 1.07, h= 25.76 ± 6.35) y 50 (L*= 3.17 ± 0.64, C*= 6.81 ± 0.53, h= 26.41 ± 4.41) presentaron los valores más bajos de los párametros de color, lo que significa que estas accesiones tuvieron un color más oscuro y más rojo. Cuatro accesiones mostraron el mayor contenido de bixina: accesión 48 (3.1%), 45 (2.6%) 43 (2.4%) and 47 (2.2%). La accession 50 mostró el mayor contenido de compuestos fenólicos totales y de tocotrienoles (T3), principalmente la isoforma δ-T3 (5.03 ± 0.64 mg g-1 Peso Seco), así como también la mayor capacidad antioxidante.Fil: Raddatz Mota, D.. Universidad Autónoma Metropolitana; MéxicoFil: Pérez Flores, L. J.. Universidad Autónoma Metropolitana; MéxicoFil: Carrari, Fernando Oscar. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Insani, Ester Marina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Asis, Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Mendoza Espinoza, J. A.. Universidad Nacional Autónoma de México; MéxicoFil: Díaz de León Sánchez, F.. Universidad Autónoma Metropolitana; MéxicoFil: Rivera Cabrera, F.. Universidad Autónoma Metropolitana; Méxic

    Implementción de servicios de Zentyal Server

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    Zentyal server es una distribución Linux/GNU que permite una adecuada gestión de servicios como DHCP, DNS controlador de dominios, proxy no transparente, cortafuegos, VPN entre otros, con una interface muy amigable y además con bastante documentación sobre su uso y configuración, este documento busca explicar su instalación además de su adecuada configuración para los servicios mencionados.Zentyal server is a Linux / GNU distribution that allows proper management of services such as DHCP, DNS, domain controller, non-transparent proxy, firewall, VPN, among others, with a very friendly interface and also with a lot of documentation on its use and configuration, This document seeks to explain its installation in addition to its adequate configuration for specific services
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