Dynamic modeling of three-phase upflow fixed-bed reactor including pore diffusion

The dynamics of a three-phase upflow fixed-bed reactor are investigated using a non-isothermal heterogeneous model including gas–liquid and liquid–solid mass transfer and diffusion/reaction phenomena inside the catalyst. The partial differential and algebraic equations involving three integration variables (time and two space coordinates) are solved via discretization of the spatial coordinates coupled with the Gear method. For a multistep hydrogenation on a shell catalyst, the model exhibits significant effects of the external and above all internal resistance to hydrogen transfer but also non-trivial internal hydrocarbons concentration profiles. A simplified model is compared with the extended one and with experimental data in transient regime. In the investigated conditions—hydrocarbons in large excess—the diffusion of hydrocarbons appears to be actually not limiting, so that the simplest model predicts accurately the transient reactor behavior

Emigration and human capital : who leaves, who comes back and what difference does it make?

This paper studies the loss of human capital that emigration generates in the country of origin. To that end I estimate the human capital distribution of emigrants had they not migrated. Unlike previous studies, I take into account the selection of migrants in terms of unobserved characteristics that affect their productivity. Wages in Mexico of those migrants who come back home after being abroad for some time will be crucial to learn something about the selection of non-returning migrants in terms of unobserved productivity. To test whether returning migrants' wages contain any useful information, I follow two steps. First, I use the model of Borjas and Bratsberg (1986) to show that, regardless of the cause for coming back, the distribution of abilities of non-returning migrants is more similar to the distribution of temporary migrants than to that of non-migrants. Moreover, I test some implications of the model in the data. Second, I show that returning migrants' wages reflect their pre-emigration productivity and are not affected by possible human capital gains derived from the decision to emigrate. Taking into account all this evidence, I use returning migrants' wages in Mexico upon return to estimate the distribution of human capital of non-returning migrants had they not migrated. I show that emigrants come form the middle part of the distribution of human capital in the origin country. I find evidence that taking unobserved human capital factors into account is relevant for the dispersion of the estimated distribution as well as for each of its quantiles. Moreover, it does not greatly affect the aggregate mean of human capital. [resumen de autor

Population at risk of poverty or social exclusion in Spain, according to the European Council

Artículo de revistaThis article describes the concept of population at risk of poverty or social exclusion that is used to quantify the targets set in this respect for the countries of the European Union. Drawing on this definition, the article analyses how poverty in Spain has evolved. It also examines the factors that have contributed to poverty levels in Spain still being above the official targets for 2020 and the average of the rest of the countries of the European Union. Lastly, some aspects of the definition are identified that suggest that the concept of economic poverty should be addressed from several complementary standpoints

Ageing, productivity and employment status

Artículo de revistaThe article analyses how labour market participation and the type of work performed change with age. Drawing on data from the OECD’s Programme for the International Assessment of Adult Competencies (PIAAC), it is documented that as people age they gradually lose certain skills relating to their ability to do physical work or use new technologies, or their literacy and numeracy skills. By contrast, as they build up experience, older workers develop better planning skills and a greater ability to supervise the work of others and respond to setbacks. However, the transition between these tasks is not problem-free, especially in certain sectors, such as agriculture, small retail trade, hotels and restaurants and domestic help, which in Spain are more likely to have a higher concentration of older workers with a lower level of education than in the rest of the euro area. In this respect, larger firm size, flexible working environments, retirement schemes with certain specificities relating to skills required in different occupations and an increase in continuing training would all be conducive to a lower decline in productivity and a higher degree of employability of older workers. This is particularly important in Spain’s current demographic context of a gradually ageing population

National productivity boards

Artículo de revist

Cyclical migration patterns

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Wage inequality in Spain : recent developments

This paper analyses wage inequality in Spain from 1995 to 2002. Inequality has decreased slightly in this period although the fall has not been constant over the whole distribution. We use non-parametric techniques to distinguish the effect on inequality of changes in the composition of the labour force and changes in relative returns. We focus mainly on three factors that have varied substantially between 1995 and 2002: female participation, educational attainment and changes in the tenure level. On one hand, changes in the composition of the labour force would have increased inequality had the structure of wages not changed in relation to the 1995 level. Changes in education and especially tenure would have been responsible for most of the higher dispersion. On the other, changes in relative returns between 1995 and 2002 are predominant and are responsible for the lower dispersion observed in the latter year. Changes in the returns to education and age are important factors underlying this decrease in inequality. [resumen de autor

Micro evidence of the brain gain hypothesis : the case of Cape Verde

Does emigration really drain human capital accumulation in origin countries? This paper explores a unique household survey purposely designed and conducted to answer this specific question for the case of Cape Verde. This is allegedly the African country suffering from the largest "brain drain", despite also having a fast-growing stock of human capital. Our micro data enables us to propose a novel, explicit test of "brain gain" arguments according to which the possibility of own future emigration positively impacts educational attainment in the origin country. The innovative empirical strategy we propose hinges on the ideal characteristics of our survey, namely on full histories of migrants and on a new set of exclusion restrictions. Our results point to a very substantial impact of the “brain gain” channel on the educational attainment of those who do not emigrate. Alternative channels (namely remittances, family disruption, and general equilibrium effects at the local level) are also considered, but do not seem to play an important role. Our findings are robust to the choice of instruments and the empirical mode

Artrosis de cadera en futbolistas. Revisión sistemática.

INTRODUCCIÓN: La artrosis es la segunda artrosis más común en pacientes de edad avanzada. En el caso de los futbolistas es muy incapacitante en el transcurso de su transcurso deportivo por los síntomas variados de esta enfermedad. OBJETIVOS: El objetivo principal de este estudio es el de estudiar la biomecánica, el tratamiento y síntomas de la coxartrosis en los futbolistas. METODOLOGÍA: Para realizar este estudio se hizo una búsqueda en la base de datos Pubmed y PEDro. Después de realizar la criba nos quedamos con 8 artículos RESULTADOS: La principal causa de la alta prevalencia de síntomas es la cantidad elevada de caderas tipo cam y ángulos alfa aumentados que existe en los futbolistas. Los síntomas físicos principales de estos suelen ser el dolor, movilidad reducida y debilidad muscular. En el caso de los futbolistas el factor psicológico juega un papel fundamental. El tratamiento fisioterapéutico consta de la cinesiterapia activa y la terapia manual. Por otro lado, existe el tratamiento farmacéutico, en el cual existen varios tipos de opciones como los AINEs, paracetamol, opioides o infiltraciones. DISCUSIÓN: Los rasgos biomecánicos específicos de los futbolistas demuestran que las mujeres tienen una mayor movilidad de la cadera y que la morfología tipo cam y el ángulo alfa aumentado, muy frecuente en futbolistas, contribuyen al desgaste articular. Por otro lado, estas lesiones pueden afectar a la salud psicológica de los futbolistas. En el caso del tratamiento del dolor se demuestra que tanto la fisioterapia y el tratamiento farmacéutico muestran mejoras significativas, pero teniendo en cuenta las contradicciones de los medicamentos y los resultados favorables de la fisioterapia, se le debería de dar más peso al tratamiento fisioterapéutico. Por último, es importante la instrucción y conciencia de los futbolistas y cuerpo técnico sobre esta enfermedad por la prevalencia y consecuencias que conlleva. CONCLUSIÓN: La biomecánica muestra diferencias de movilidad entre géneros y gran prevalencia de cambios estructurales. Los síntomas psicológicos y físicos disminuyen la calidad de vida y efectividad de los futbolistas. Se subraya la importancia de la fisioterapia en el tratamiento de los diferentes síntomasGrado en Fisioterapi

Heterogeneity of the impact of the Spanish programme of incentives for the purchase of electric vehicles

Artículo de revistaPromoting e-mobility in the transport sector is essential for the transition to a low-emission economy. One of the goals of the Spanish programmes of incentives for efficient and sustainable mobility (MOVES) is to encourage the general public and firms to purchase electric vehicles. This article analyses the impact of the MOVES II programme, launched in June 2020, on electric vehicle registrations, based on the microdata provided by the Directorate General for Traffic. The results suggest that the impact has been very uneven across Spain’s regions. Specifically, from its launch up to December 2020, the programme appears to have increased the percentage of new electric vehicle registrations in Asturias, Madrid, Navarre and the Balearic Islands, and on average in the provinces of Catalonia, by an average of at least 1 percentage point. By contrast, the average impact on electric vehicle registrations by province in each of the other regions may be statistically zero