Efectos y consecuencias económicas de la inmigración de trabajadores educados

Buscamos analizar la inmigración de trabajadores más calificados hacia un nuevo país y su correspondiente impacto sobre los sectores de la economía local y el salario de equilibrio. La idea de este trabajo tiene sus raíces en el análisis de Iranzo y Peri (2009)2 en el cual se comparan las consecuencias de las migraciones entre Europa Oriental y Occidental, y sus repercusiones en el comercio internacional. A diferencia de los autores, que en la primera parte de su trabajo utilizan una función de utilidad CES, nosotros la hemos adaptado correspondientemente para nuestro modelo a una función de producción Cobb- Douglas. En la primera sección del trabajo desarrollaremos un modelo de factores específicos en el cual tomaremos como factor móvil al trabajo y asignaremos un factor específico a cada uno de los 2 sectores de la economía (tierra y capital). Asumiremos que un sector de la economía posee una productividad mayor al otro sector, y que esto se debe a que el mismo cuenta con una masa de trabajadores de "mayor calidad". Una vez determinado esto, procederemos a analizar los efectos ocasionados por un aumento en la productividad en el sector menos productivo junto con un aumento en la cantidad total de trabajadores del país. Dicho aumento en el número total de trabajadores se debe a un proceso migratorio, el cual estará compuesto en su totalidad por trabajadores de "mayor calidad" que deberán dirigirse, sin excepción, al sector de menor productividad de la economía. En la segunda sección del presente trabajo elaboraremos nuevamente un modelo de factores específicos, con la diferencia de que ahora tomaremos como factores específicos dos diferentes tipos de trabajo que pueden ser interpretados como “trabajo de alta calidad” y “trabajo de baja calidad” en relación a, por ejemplo, su nivel educativo; mientras que el factor móvil será el capital. Por último, serán presentadas las conclusiones obtenidas a partir del análisis de cada una de las secciones previamente descritas.Por motivos relacionados con los derechos de autor este documento solo puede ser consultado en la Biblioteca Di Tella. Para reservar una cita podés ponerte en contacto con [email protected]. Si sos el autor de esta tesis y querés autorizar su publicación en este repositorio, podés ponerte en contacto con [email protected]

Climate and land-use change during the late Holocene at Lake Ledro (southern Alps, Italy)

International audienceThis paper investigates the relative influences of climatic and anthropogenic factors in explaining environmental and societal changes in the southern Alps, Italy. We investigate a deep sediment core (LL081) from Lake Ledro (652 m a.s.l.). Environmental changes are reconstructed through multiproxy analysis, that is, pollen-based vegetation and climate reconstruction, magnetic susceptibility (MS), lake level, and flood frequency, and the paper focuses on the climate and land-use changes which occurred during the late Holocene. For this time interval, Lake Ledro records high mean water table, increasing amount of pollen-based precipitation, and more erosive conditions. Therefore, while a more humid late Holocene in the southern Alps has the potential to reinforce the forest presence, pollen evidence suggests that anthropogenic activities changed the impact of this regional scenario. Land-use activity (forest clearance for pastoralism, farming, and arboriculture) opened up the large vegetated slopes in the catchment of Lake Ledro, which in turn magnified the erosion related to the change in the precipitation pattern. The record of an almost continuous human occupation for the last 4100 cal. BP is divided into several land-use phases. On the one hand, forest redevelopments on abandoned or less cultivated areas appear to be climatically induced as they occurred in relation with well-known events such as the 2.8-kyr cold event and the ‘Little Ice Age’. On the other hand, climatically independent changes in land use or habitat modes are observed, such as the late-Bronze-Age lake-dwellings abandonment, the human population migration at c. 1600 cal. BP, and the period of the Black Death and famines at 600 cal. BP

Modeling and Simulation of a miRNA Regulatory Network of the PTEN Gene

The PTEN onco-suppressor gene is likely to play an important role in the onset of brain cancer, namely glioblastoma multiforme. Consequently, the PTEN regulatory network, involving microRNAs and competitive endogenous RNAs, becomes a crucial tool for understanding the mechanism related to low levels of expression in cancer patients. This paper introduces a novel model for the regulation of PTEN whose solution is approximated by a high-dimensional system of ordinary differential equations under the assumption that the Law of Mass Action applies. Extensive numerical simulations are presented that mirror parts of the biological subtext that lies behind various alterations. Given the complexity of processes involved in the acquisition of empirical data, initial conditions and reaction rates were inferred from the literature. Despite this, the proposed model is shown to be capable of capturing biologically reasonable behaviors of inter-species interactions, thus representing a positive result, which encourages pursuing the possibility of experimenting on data hopefully provided by omics disciplines

Identification, Expression and Preliminary Characterization of a Recombinant Bifunctional Enzyme of Photobacterium damselae subsp. piscicida with Glutamate Decarboxylase/Transaminase Activity

Glutamate decarboxylase catalyzes the conversion of glutamate to gamma-aminobutyric acid (GABA), contributing to pH homeostasis through proton consumption. The reaction is the first step toward the GABA shunt. To date, the enzymes involved in the glutamate metabolism of Photobacterium damselae subsp. piscicida have not been elucidated. In this study, an open reading frame of P. damselae subsp. piscicida, showing homology to the glutamate decarboxylase or putative pyridoxal-dependent aspartate 1-decarboxylase genes, was isolated and cloned into an expression vector to produce the recombinant enzyme. Preliminary gas chromatography-mass spectrometry characterization of the purified recombinant enzyme revealed that it catalyzed not only the decarboxylation of glutamate but also the transamination of GABA. This enzyme of P. damselae subsp. piscicida could be bifunctional, combining decarboxylase and transaminase activities in a single polypeptide chain