396 resultados para Impacte
Resumo:
The New Economic Geography literature allows detailed analysis of the factors that determine the location decisions of firms in integrated markets. However, the competitive process is modelled in a rather rudimentary way, and the empirical evidence has usually been obtained from reduced-form econometric specifications. This study describes a structural model that takes into account strategic interactions between firms. We investigate the relationship between the degree of perceived competition ¿ not only from local firms but from firms in other regions ¿ and geographic concentration. The preliminary results indicate that, in aggregate terms, local firms present stronger competition than firms in other regions. Moreover, it is confirmed that greater geographical concentration of production reduces market power, due to the intensification of local competition; however, its impact on production costs is unclear.
Resumo:
The changes undergone by the Si surface after oxygen bombardment have special interest for acquiring a good understanding of the Si+-ion emission during secondary ion mass spectrometry (SIMS) analysis. For this reason a detailed investigation on the stoichiometry of the builtup surface oxides has been carried out using in situ x-ray photoemission spectroscopy (XPS). The XPS analysis of the Si 2p core level indicates a strong presence of suboxide chemical states when bombarding at angles of incidence larger than 30°. In this work a special emphasis on the analysis and interpretation of the valence band region was made. Since the surface stoichiometry or degree of oxidation varies with the angle of incidence, the respective valence band structures also differ. A comparison with experimentally measured and theoretically derived Si valence band and SiO2 valence band suggests that the new valence bands are formed by a combination of these two. This arises from the fact that Si¿Si bonds are present on the Si¿suboxide molecules, and therefore the corresponding 3p-3p Si-like subband, which extends towards the Si Fermi level, forms the top of the respective new valence bands. Small variations in intensity and energy position for this subband have drastic implications on the intensity of the Si+-ion emission during sputtering in SIMS measurements. A model combining chemically enhanced emission and resonant tunneling effects is suggested for the variations observed in ion emission during O+2 bombardment for Si targets.
Resumo:
The variation in the emission of Si+ ions from ion-beam-induced oxidized silicon surfaces has been studied. The stoichiometry and the electronic structure of the altered layer has been characterized using x-ray photoelectron spectroscopy (XPS). The XPS analysis of the Si 2p core level indicates the strong presence of suboxide chemical states when bombarding at angles of incidence larger than 30 °. Since the surface stoichiometry or degree of oxidation varies with the angle of incidence, the corresponding valence-band structures also differ among each other. A comparison between experimental measurements and theoretically calculated Si and SiO2 valence bands indicates that the valence bands for the altered layers are formed by a combination of those two. Since Si-Si bonds are present in the suboxide molecules, the top of the respective new valence bands are formed by the corresponding 3p-3p Si-like subbands, which extend up to the Si Fermi level. The changes in stoichiometry and electronic structure have been correlated with the emission of Si+ ions from these surfaces. From the results a general model for the Si+ ion emission is proposed combining the resonant tunneling and local-bond-breaking models.
Resumo:
Most studies analysing the infrastructure impact on regional growth show a positive relationship between both variables. However, the public capital elasticity estimated in a Cobb-Douglas function, which is the most common specification in these works, is sometimes too big to be credible, so that the results have been partially desestimated. In the present paper, we give some new advances on the real link between public capital and productivity for the Spanish regions in the period 1964-1991. Firstly, we find out that the association for both variables is smaller when controlling for regional effects, being industry the sector which reaps the most benefits from an increase in the infrastructural dotation. Secondly, concerning to the rigidity of the Cobb-Douglas function, it is surpassed by using the variable expansion method. The expanded functional form reveals both the absence of a direct effect of infrastructure and the fact that the link between infrastructure and growth depends on the level of the existing stock (threshold level) and the way infrastructure is articulated in its location relative to other factors. Finally, we analyse the importance of the spatial dimension in infrastructure impact, due to spillover effects. In this sense, the paper provides evidence of the existence of spatial autocorrelation processes that may invalidate previous results.
Resumo:
The New Economic Geography literature allows detailed analysis of the factors that determine the location decisions of firms in integrated markets. However, the competitive process is modelled in a rather rudimentary way, and the empirical evidence has usually been obtained from reduced-form econometric specifications. This study describes a structural model that takes into account strategic interactions between firms. We investigate the relationship between the degree of perceived competition ¿ not only from local firms but from firms in other regions ¿ and geographic concentration. The preliminary results indicate that, in aggregate terms, local firms present stronger competition than firms in other regions. Moreover, it is confirmed that greater geographical concentration of production reduces market power, due to the intensification of local competition; however, its impact on production costs is unclear.
Resumo:
As adult height is a well-established retrospective measure of health and standard of living, it is important to understand the factors that determine it. Among them, the influence of socio-environmental factors has been subjected to empirical scrutiny. This paper explores the influence of generational (or environmental) effects and individual and gender-specific heterogeneity on adult height. Our data set is from contemporary Spain, a country governed by an authoritarian regime between 1939 and 1977. First, we use normal position and quantile regression analysis to identify the determinants of self-reported adult height and to measure the influence of individual heterogeneity. Second, we use a Blinder-Oaxaca decomposition approach to explain the `gender height gap¿ and its distribution, so as to measure the influence on this gap of individual heterogeneity. Our findings suggest a significant increase in adult height in the generations that benefited from the country¿s economic liberalization in the 1950s, and especially those brought up after the transition to democracy in the 1970s. In contrast, distributional effects on height suggest that only in recent generations has ¿height increased more among the tallest¿. Although the mean gender height gap is 11 cm, generational effects and other controls such as individual capabilities explain on average roughly 5% of this difference, a figure that rises to 10% in the lowest 10% quantile.
Resumo:
[cat] Una qüestió clau sobre la producció de salut relativament poc explorada es refereix a la influència dels factors socioeconòmics i mediambientals sobre el pes i l’obesitat. Aquesta problemàtica adquireix particular rellevància quan es comparen dos països Mediterranis com Itàlia i Espanya. És interessant adonar-se que l’obesitat a Espanya és 5 punts percentual més elevada al 2003 mentre que a l’any 1990 era aproximadament la mateixa en ambdós països. Aquesta article presenta una descomposició no lineal dels gaps o diferencials en taxes de sobrepès (índex de massa corporal – IMC- entre 25 i 29.9 9 kg/m2), obesitat classe 1 (IMC≥30 kg/m2) i classe 2 (IMC≥35 kg/m2) entre Espanya i Itàlia per gènere i grups d’edat. En explicar aquests gaps entre països aïllem les influències dels estils de vida, els efectes socioeconòmics i els mediambientals. Els nostres resultats indiquen que quan no es controla pels efectes mediambientals (efectes de grup o ‘peer effects’) els hàbits alimentaris i el nivell educatiu són els principals predictors del gaps totals entre països (36-52%), si bé aquests dos factors exerceixen un impacte diferenciat segons gènere i edat. Un tant paradoxalment, quan controlem pels efectes de grup aquests predictors perden la seva capacitat explicativa i els efectes de grup passen a explicar entre el 46-76% dels gaps en sobrepès i obesitat i mostren un patró creixent amb l’edat.
Resumo:
La construcción de autovías disminuye el coste temporal del viaje por carretera, con efectos sobre la demanda del transporte por carretera. Pero, además de los efectos intramodales, existen efectos intermodales, puesto que las autovías afectan a la demanda en otros modos alternativos a la carretera. En este trabajo formulamos y contrastamos empíricamente un modelo que permite obtener resultados para evaluar el impacto de las autovías sobre la demanda de ferrocarril. Seguidamente se pronostican algunos efectos sobre la demanda ferroviaria de algunas actuaciones en infraestructuras viarias incluidas en el Plan Director de Infraestructuras (1993-2007).
Resumo:
La literatura económica sobre los servicios municipales de residuos sólidos en España es muy escasa, aun cuando estos servicios han sido objeto d'intensas reformas organizativas y regulatorias. En esta investigación se estudia su estructura de costes con el objetivo de explicar la variabilidad entre los municipios de los costes soportados por el servicio. Se determina una función de costes y se estima de forma paramétrica. Los resultados del análisis empírico permiten estudiar la existencia de economías de escala con el output, y el efecto de algunos factores directamente asociados con el servicio como el grado de residuos selectivos, la frecuencia de recogida o la existencia de instalaciones de depósito en el municipio. Además, se analiza el impacto sobre los costes de otros factores como la densidad de población, los niveles salariales, la estacionalidad y la forma de producción, pública o privada.
Resumo:
The objective of this work is to study the impact of the unions' bargaining power on production and wages. We present a model where a competitive final good is produced through two substitutable intermediate goods, one produced by unskilled labor and the other by skilled labor. Potential workers decide at their cost to become skilled or unskilled and, thus, labor supplies are determined endogenously. We find that the reallocation of the labor supplies due to changes in the unskilled (or skilled) unions¿ bargaining power may have a positive impact on the final goods production. At the same time, total labor earnings increase with the unskilled unions¿ bargaining power if the final goods production increases too. We also show that the minimum wage legislation has efects similar to an increase in the bargaining power of the unskilled unions.
Resumo:
This paper investigates the contribution of public investment to the reduction of regional inqualities, with a specific application to Mexico. We use quantile regressions to examine the impact of public investment on regional disparities according to the position of each region in the conditional distribution of regional income. Results confirm the hypothesis that regional inequalities can indeed be atrributed to the regional distribution of public investment, where the observed pattern shows that public investment mainly helped to reduce regional inequalities between the richest regions
Resumo:
[spa] Este texto forma parte de un proyecto de investigación Los efectos de los cambios sociales en el trabajo y la vida profesional de los docentes universitarios, parcialmente financiado por el Ministerio de Ciencia e Innovación (SEJ2006-01876), en el que nos planteamos explorar los cambios los ámbitos de la legislación, laorganización institucional, la investigación, la gestión y la docencia en los últimos treinta años. El principal objetivo del estudio era profundizar en nuestra comprensión sobre el impacto del cambio económico, social, cultural, tecnológico y laboral que están experimentando las universidades españolas en la vida y la identidad profesional del personal docente e investigador, teniendo en cuenta el contexto nacional y europeo. Estapublicación recoge la 24 historias de vida profesional realizas con o sobre otros tantos docentes universitarios. Sus relatos analizados y contextualizados, significan una contribución significativa al conocimiento basado en la investigación sobre el saber profesional y la experiencia laboral en las universidades españolas, y en consecuencia, a nuestra comprensión sobre cómo los académicos se están enfrentando con los cambios actuales.
Resumo:
Es presenten els resultats obtinguts en el projecte de recerca finançat per l'ICE-UB que porta per títol: Projecte d'estudi sobre l'avaluació de l'impacte (grau de satisfacció) dels projectes d'aprenentatge-servei.
Resumo:
La construcción de autovías disminuye el coste temporal del viaje por carretera, con efectos sobre la demanda del transporte por carretera. Pero, además de los efectos intramodales, existen efectos intermodales, puesto que las autovías afectan a la demanda en otros modos alternativos a la carretera. En este trabajo formulamos y contrastamos empíricamente un modelo que permite obtener resultados para evaluar el impacto de las autovías sobre la demanda de ferrocarril. Seguidamente se pronostican algunos efectos sobre la demanda ferroviaria de algunas actuaciones en infraestructuras viarias incluidas en el Plan Director de Infraestructuras (1993-2007).
Resumo:
La literatura económica sobre los servicios municipales de residuos sólidos en España es muy escasa, aun cuando estos servicios han sido objeto d'intensas reformas organizativas y regulatorias. En esta investigación se estudia su estructura de costes con el objetivo de explicar la variabilidad entre los municipios de los costes soportados por el servicio. Se determina una función de costes y se estima de forma paramétrica. Los resultados del análisis empírico permiten estudiar la existencia de economías de escala con el output, y el efecto de algunos factores directamente asociados con el servicio como el grado de residuos selectivos, la frecuencia de recogida o la existencia de instalaciones de depósito en el municipio. Además, se analiza el impacto sobre los costes de otros factores como la densidad de población, los niveles salariales, la estacionalidad y la forma de producción, pública o privada.