959 resultados para Casual labor


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In agricultural societies, adjusting land and labor according to changes of labor endowment that result from family life cycle events is premised on making full use of resources for each farming household and for the economy as a whole. This paper examines how and how well households in pre-modern Japan reallocated land and labor, using a population register covering 150 years from 1720–1870 for a village in the Tohoku region. We find that households reacted to equalize their production factors; land-scarce households tended to acquire or rent-in land and out-migrate their kin members, while land-abundant households tended to release or rent-out land, in-migrate kin members, or employ non-kin members. Estimates suggest that more than 80% of the surplus or deficit area of land was resolved if the household rented or "sold" land. We discuss a potential underlying mechanism; namely, that the village's collective responsibility for tax payment (murauke) motivated both individual households and the village as a whole to reallocate land and labor for the efficient use of resources.

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This paper compares three knowledge carriers—trade, foreign direct investment (FDI), and inventors—as knowledge mediums, and investigates their effects on knowledge flow in East Asia from 1996 to 2010. Using patent citations as a proxy for knowledge flow, this paper shows that FDI and inventor mobility have positive effects on increasing patent citations in East Asia when the technological portfolios of two countries are less similar. While trade shows statistical significance, the effect is inconsistent according to the regression models.

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El cumplimiento de los objetivos agrotécnicos de los cultivos de raíces y tubérculos exige que la labor de surcado configure un caballón que permita el trabajo de los posteriores aperos que participan en las demás labores de cultivo. En la agricultura cubana se emplean diversos tipos de surcadores que difieren en las características de los elementos aporcadores. Este hecho afecta a la capacidad de trabajo del conjunto tractor-apero y por extensión en el consumo de combustible y el rendimiento del cultivo. El objetivo de este trabajo ha sido fundamentar el empleo del apero más adecuado para la labor de surcado en cultivos de raíces y tubérculos (patata, boniato, yuca) en Fluvisoles, teniendo en cuenta el comportamiento de las dimensiones y forma del caballón, cualidades tecnológicas explotativas del conjunto tractor-apero, consumo energético del proceso productivo y el rendimiento agrícola. Los tratamientos considerados estuvieron determinados por la utilización del surcador fertilizador IIMA-BALDAN 4.500 (T1), y los surcadores aporcadores SA-5 (T2) y SA-3 (T3). En los tres tratamientos se alcanzó un perfil de la sección transversal del caballón de configuración cóncavo-convexo. El surcador BALDAN logró el mejor comportamiento de los indicadores tecnológico-explotativos lo que se tradujo en la mayor capacidad de trabajo de 1,36 ha h-1 y el menor consumo de combustible de 5,38 L ha-1. Este mismo tratamiento proporcionó el mayor rendimiento medio de los cultivos superando en un 43,2% al del surcador SA-5 y en un 57,9% al del surcador SA-3. Desde el punto de vista energético T1, obtuvo una mejor eficiencia energética superior en un 43,5% a la del tratamiento T2, y en un 57,1% a la del tratamiento T3. ABSTRACT The achievement of agrotechnical objectives in the cultivation of roots and tubers demands the plow through activity creates a ridge to allow the work of subsequent farming tools participating in other cultivation works. In Cuban Agriculture various kinds of furrowers are used which differ in the characteristics of their earth up elements. This fact affects work capacity of the tractor-farming tool combination and by extension to fuel consumption and cultivation yield. The aim of this work has been to support the use of the most accurate farming tool in the plow through activity for the cultivation of roots and tubers (potato, sweet potato, cassava) in Fluvisoils, taking into account the behaviour of the ridge´s dimensions and shape, technologic-explotative qualities of the tractor-farming tool combination, energy consumption of the productive process and agricultural yield. The treatments considered were determined by the use of fertlizing furrower IIMA-BALDAN 4.500 (T1), and the earth up furrowers SA-5 (T2) and SA-3 (T3). During the three treatments a transverse section profile of the ridge under concave-convex configuration was obtained. The furrower BALDAN achieved the best behaviour of the technologic-explotative indicators, which was translated into the largest work capacity of 1,36 ha h-1 and the smallest fuel consumption of 5,38 L ha-1. This treatment also provided the biggest average yield of the cultivation, overcoming in a 43,2% the furrower SA-5 and furrower SA-3 in a 57,9%. From the energetic point of view T1 gained better energetic efficiency than treatment T2 in a 43,5% and treatment T3 in a 57,1%.

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La norma UNE 153010:2003 recogía requisitos para el subtitulado para personas sordas a través de teletexto. Fue el resultado de varios años de trabajo en el Subcomité 5 del Comité Técnico de Normalización (CTN) 153 de AENOR. Los cambios en los últimos años en cuanto a los medios audiovisuales llevaron a dicho Subcomité a plantearse en el año 2008 la posibilidad de actualizar los contenidos de esta norma, con el fin de adaptarse a nuevas tecnologías, como los DVD, la televisión digital o la televisión emitida a través de Internet. Inicialmente se planteó la posibilidad de realizar normas específicas de subtitulado para cada tecnología de emisión, pero finalmente se decidió desarrollar una norma general de subtitulado que fuera de aplicación general. Tras un largo periodo de trabajo, la nueva versión de la norma UNE 153010 está a punto de ver la luz, dado que se encuentra en periodo de información pública. En este artículo se narra el proceso de desarrollo de esta norma y se describe los aspectos más importantes de la misma, resultado de una intensa labor con gran voluntad de consenso por parte de las entidades implicadas.

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Estudio analítico del tipo de vivienda de labradores en Extremadura como ejemplo de arquitectura popular doméstica.

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Entrevista personal. Alfredo Blanco, Premio UPM Investigación para el Desarrollo.

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Division of labor is a widely studied aspect of colony behavior of social insects. Division of labor models indicate how individuals distribute themselves in order to perform different tasks simultaneously. However, models that study division of labor from a dynamical system point of view cannot be found in the literature. In this paper, we define a division of labor model as a discrete-time dynamical system, in order to study the equilibrium points and their properties related to convergence and stability. By making use of this analytical model, an adaptive algorithm based on division of labor can be designed to satisfy dynamic criteria. In this way, we have designed and tested an algorithm that varies the response thresholds in order to modify the dynamic behavior of the system. This behavior modification allows the system to adapt to specific environmental and collective situations, making the algorithm a good candidate for distributed control applications. The variable threshold algorithm is based on specialization mechanisms. It is able to achieve an asymptotically stable behavior of the system in different environments and independently of the number of individuals. The algorithm has been successfully tested under several initial conditions and number of individuals.

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The influence of training in labor risk prevention and the development of the resulting pre-emptive culture are analyzed within this paper. In order to achieve this, a quantitative analysis of the students of Building Degree in the Technic University of Madrid has been developed. This study has been made in all grades, valuating the previous knowledge acquired during compulsory education. It must be kept in mind that the students in 3rd and 4th grade have received general and specific compulsory training in prevention and safety in the building sector.

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Contact of cultured mammary epithelial cells with the basement membrane protein laminin induces multiple responses, including cell shape changes, growth arrest, and, in the presence of prolactin, transcription of the milk protein β-casein. We sought to identify the specific laminin receptor(s) mediating the multiple cell responses to laminin. Using assays with clonal mammary epithelial cells, we reveal distinct functions for the α6β4 integrin, β1 integrins, and an E3 laminin receptor. Signals from laminin for β-casein expression were inhibited in the presence of function-blocking antibodies against both the α6 and β1 integrin subunits and by the laminin E3 fragment. The α6-blocking antibody perturbed signals mediated by the α6β4 integrin, and the β1-blocking antibody perturbed signals mediated by another integrin, the α subunit(s) of which remains to be determined. Neither α6- nor β1-blocking antibodies perturbed the cell shape changes resulting from cell exposure to laminin. However, the E3 laminin fragment and heparin both inhibited cell shape changes induced by laminin, thereby implicating an E3 laminin receptor in this function. These results elucidate the multiplicity of cell-extracellular matrix interactions required to integrate cell structure and signaling and ultimately permit normal cell function.

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We report the isolation and expression of the Hox gene, Cnox-2, in Hydractinia symbiolongicarpus, a hydrozoan displaying division of labor. We found different patterns of aboral-to-oral Cnox-2 expression among polyp polymorphs, and we show that experimental conversion of one polyp type to another is accompanied by concordant alteration in Cnox-2 expression. Our results are consistent with the suggestion that polyp polymorphism, characteristic of hydractiniid hydroids, arose via evolutionary modification of proportioning of head to body column.

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Temporal polyethism is a highly derived form of behavioral development displayed by social insects. Hormonal and genetic mechanisms regulating temporal polyethism in worker honey bees have been identified, but the evolution of these mechanisms is not well understood. We performed three experiments with male honey bees (drones) to investigate how mechanisms regulating temporal polyethism may have evolved because, relative to workers, drones display an intriguing combination of similarities and differences in behavioral development. We report that behavioral development in drones is regulated by mechanisms common to workers. In experiment 1, drones treated with the juvenile hormone (JH) analog methoprene started flying at significantly younger ages than did control drones, as is the case for workers. In experiment 2, there was an age-related increase in JH associated with the onset of drone flight, as in workers. In experiment 3, drones derived from workers with fast rates of behavioral development themselves started flying at younger ages than drones derived from workers with slower rates of behavioral development. These results suggest that endocrine and genetic mechanisms associated with temporal polyethism did not evolve strictly within the context of worker social behavior.

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In the period 1999-2007 Spanish imports from China multiplied by six, making that Asian country the fourth largest supplier to the Spanish economy. In this paper, we analyse whether this massive increase in imports impacted on the labour markets of Spanish provinces to differing degrees, due to differences in their initial productive specialization. Our results show that Spanish provinces with a higher exposure to Chinese imports experienced larger drops in manufacturing employment as a share of the working-age population. However, this reduction was compensated for by increases in non-manufacturing employment.