Unitats litològiques d'interès per a la producció d'àrids a l'àrea del curs mitjà del riu Fluvià (la Garrotxa)

Pleistocene and Quaternary sediments adjacent to the medium course of the Fluvià river are a source of aggregate in the Garrotxa. Four lithological units can be used directly, or with a minimal processing as coarse aggregate. They have been mapped in detail at the 1:5.000 escale. The stratigraphic analysis have made possible the four units to be ordered in relation to their suitibility for usage as aggregate. From high to low relative quality they are: the basaltic flow, fluviatile deposits, plio-quaternary conglomerates, and glacis deposits

A wavelet-based method for the determination of the relative resolution between remotely sensed images

Spatial resolution is a key parameter of all remote sensing satellites and platforms. The nominal spatial resolution of satellites is a well-known characteristic because it is directly related to the area in ground that represents a pixel in the detector. Nevertheless, in practice, the actual resolution of a specific image obtained from a satellite is difficult to know precisely because it depends on many other factors such as atmospheric conditions. However, if one has two or more images of the same region, it is possible to compare their relative resolutions. In this paper, a wavelet-decomposition-based method for the determination of the relative resolution between two remotely sensed images of the same area is proposed. The method can be applied to panchromatic, multispectral, and mixed (one panchromatic and one multispectral) images. As an example, the method was applied to compute the relative resolution between SPOT-3, Landsat-5, and Landsat-7 panchromatic and multispectral images taken under similar as well as under very different conditions. On the other hand, if the true absolute resolution of one of the images of the pair is known, the resolution of the other can be computed. Thus, in the last part of this paper, a spatial calibrator that is designed and constructed to help compute the absolute resolution of a single remotely sensed image is described, and an example of its use is presented.

A virtual exhibition of open source software for libraries

Frequently the choice of a library management program is conditioned by social, economic and/or political factors that result in the selection of a system that is not altogether suitable for the library’s needs, characteristics and functions. Open source software is quickly becoming a preferred solution, owing to the freedom to copy, modify and distribute it and the freedom from contracts, as well as for greater opportunities for interoperability with other applications. These new trends regarding open source software in libraries are also reflected in LIS studies, as evidenced by the different courses addressing automated programs, repositorymanagement, including the Linux/GNU operating system, among others. The combination of the needs of the centres and the new trends for open source software is the focus of a virtual laboratory for the use of open source software for library applications. It was the result of a project, whose aim was to make a useful contribution to the library community, that was carried out by a group of professors of the School of Library and Information Science of the University of Barcelona, together with a group of students, members of a Working Group on Open Source Software for Information Professionals, of the Professional Library Association of Catalonia.

Microsatellite markers reveal shallow genetic differentiation between cohorts of the common sea urchin Paracentrotus lividus (Lamarck) in northwest Mediterranean

Temporal variability was studied in the common sea urchin Paracentrotus lividus through the analysis of the genetic composition of three yearly cohorts sampled over two consecutive springs in a locality in northwestern Mediterranean. Individuals were aged using growth ring patterns observed in tests and samples were genotyped for five microsatellite loci. No reduction of genetic diversity was observed relative to a sample of the adult population from the same location or within cohorts across years. FST and amova results indicated that the differentiation between cohorts is rather shallow and not significant, as most variability is found within cohorts and within individuals. This mild differentiation translated into estimates of effective population size of 90100 individuals. When the observed excess of homozygotes was taken into account, the estimate of the average number of breeders increased to c. 300 individuals. Given our restricted sampling area and the known small-scale heterogeneity in recruitment in this species, our results suggest that at stretches of a few kilometres of shoreline, large numbers of progenitors are likely to contribute to the larval pool at each reproduction event. Intercohort variation in our samples is six times smaller than spatial variation between adults of four localities in the western Mediterranean. Our results indicate that, notwithstanding the stochastic events that take place during the long planktonic phase and during the settlement and recruitment processes, reproductive success in this species is high enough to produce cohorts genetically diverse and with little differentiation between them. Further research is needed before the link between genetic structure and underlying physical and biological processes can be well established.

Industrial agglomerations and wage gradients: the Spanish economy in the interwar period

This paper gives new evidence on the relationship between integration and industrial agglomeration in the presence of scale economies, by testing directly one of the predictions that can be derived from Krugman (1991), that is, the existence of regional nominal wage gradients and its transformation following changes in trade regimes. Our case study analyzes the effects of the substitution of an open economy by a closed economy regime, exactly the opposite process studied by Hanson (1996, 1997). In Spain, during the interwar period, protectionist policies would have favored the loss of centrality of the coastal location (Barcelona) and the relative rise of central locations (such as Madrid). Our results indicate the existence of a wage gradient centered in Barcelona during the interwar period (1914-1930) and its weakening after 1925.

Evidence on the complex link between

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.

Integración económica y localización industrial. Cataluña, la fábrica de España: ¿cuándo y por qué?

En este artículo se analizan los determinantes de la localización de la actividad industrial en España durante la segunda mitad del siglo XIX. El objetivo es estudiar la existencia de cambios en los factores explicativos de la localización, con el fin de identificar los efectos de la integración económica sobre la geografía industrial española. Para hacerlo, en primer lugar se analiza la literatura histórica existente. En segundo lugar, se describen las teorías que explican la localización de l'actividad. En tercer lugar, se realiza un análisis empírico de la localización y la concentración de la industria española al siglo XIX. A continuación, se propone un estudio econométrico de los determinantes de la localización industrial en dos cortes temporales, 1856 y 1893. Los resultados son consistentes con las teorías del comercio. Durante el decurso de la segunda mitad del siglo XIX, España paso a ser una economía integrada, la movilidad del trabajo y del capital se vio favorecida y como resultado, las diferencias relativas en las dotaciones de factores perdieron importancia en la explicación de las pautas de especialización industrial. Por el contrario, la integración económica favoreció la significación relativa de las economías de escala o de la proximidad a los mercados como elementos explicativos de la localización de la industria, favoreciendo, de esta manera, la aglomeración de la actividad industrial

Tax differentials and agglomeration economies in intraregional firm location

This paper analyses empirically how differences in local taxes affect the intraregional location of new manufacturing plants. These effects are examined within the random profit maximization framework while accounting for the presence of different types of agglomeration economies (localization/ urbanization/ Jacobs¿ economies) at the municipal level. We look at the location decision of more than 10,000 establishments locating between 1996 and 2003 across more than 400 municipalities in Catalonia, a Spanish region. It is necessary to restrict the choice set to the local labor market and, above all, to control for agglomeration economies so as to identify the effects of taxes on the location of new establishments.

Polarization strategies to improve the emission of a Si-based light source emitting at 1.55 um

We present a electroluminescence (EL) study of the Si-rich silicon oxide (SRSO) LEDs with and without Er3+ ions under different polarization schemes: direct current (DC) and pulsed voltage (PV). The power efficiency of the devices and their main optical limitations are presented. We show that under PV polarization scheme, the devices achieve one order of magnitude superior performance in comparison with DC. Time-resolved measurements have shown that this enhancement is met only for active layers in which annealing temperature is high enough (>1000 ◦C) for silicon nanocrystal (Si-nc) formation. Modeling of the system with rate equations has been done and excitation cross-sections for both Si-nc and Er3+ ions have been extracted.

Were Spanish migrants attracted by industrial agglomerations?: an analysis for the interwar years in the light of the new economic geography

In this paper we examine whether access to markets had a significant influence onmigration choices of Spanish internal migrants in the inter-war years. We perform astructural contrast of a New Economic Geography model that focus on the forwardlinkage that links workers location choice with the geography of industrial production,one of the centripetal forces that drive agglomeration in the NEG models. The resultshighlight the presence of this forward linkage in the Spanish economy of the inter-warperiod. That is, we prove the existence of a direct relation between workers¿ localizationdecisions and the market potential of the host regions. In addition, the direct estimationof the values associated with key parameters in the NEG model allows us to simulatethe migratory flows derived from different scenarios of the relative size of regions andthe distances between them. We show that in Spain the power of attraction of theagglomerations grew as they increased in size, but the high elasticity estimated for themigration costs reduced the intensity of the migratory flows. This could help to explainthe apparently low intensity of internal migrations in Spain until its upsurge during the1920s. This also explains the geography of migrations in Spain during this period,which hardly affected the regions furthest from the large industrial agglomerations (i.e.,regions such as Andalusia, Estremadura and Castile-La Mancha) but had an intenseeffect on the provinces nearest to the principal centres of industrial development.

Evidence on the complex link between

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.

Tax differentials and agglomeration economies in intraregional firm location

This paper analyses empirically how differences in local taxes affect the intraregional location of new manufacturing plants. These effects are examined within the random profit maximization framework while accounting for the presence of different types of agglomeration economies (localization/ urbanization/ Jacobs¿ economies) at the municipal level. We look at the location decision of more than 10,000 establishments locating between 1996 and 2003 across more than 400 municipalities in Catalonia, a Spanish region. It is necessary to restrict the choice set to the local labor market and, above all, to control for agglomeration economies so as to identify the effects of taxes on the location of new establishments.

Integración económica y localización industrial. Cataluña, la fábrica de España: ¿cuándo y por qué?

En este artículo se analizan los determinantes de la localización de la actividad industrial en España durante la segunda mitad del siglo XIX. El objetivo es estudiar la existencia de cambios en los factores explicativos de la localización, con el fin de identificar los efectos de la integración económica sobre la geografía industrial española. Para hacerlo, en primer lugar se analiza la literatura histórica existente. En segundo lugar, se describen las teorías que explican la localización de l'actividad. En tercer lugar, se realiza un análisis empírico de la localización y la concentración de la industria española al siglo XIX. A continuación, se propone un estudio econométrico de los determinantes de la localización industrial en dos cortes temporales, 1856 y 1893. Los resultados son consistentes con las teorías del comercio. Durante el decurso de la segunda mitad del siglo XIX, España paso a ser una economía integrada, la movilidad del trabajo y del capital se vio favorecida y como resultado, las diferencias relativas en las dotaciones de factores perdieron importancia en la explicación de las pautas de especialización industrial. Por el contrario, la integración económica favoreció la significación relativa de las economías de escala o de la proximidad a los mercados como elementos explicativos de la localización de la industria, favoreciendo, de esta manera, la aglomeración de la actividad industrial

The determinants of industrial location in Spain, 1856-1929

Durant el segle XIX, l'economia espanyola va transitar per les primeres etapes de la industrialització. Aquest procés es va donar en paral·lel a la integració del mercat domèstic de béns i factors, en un moment en què les reformes liberals i la construcció de la xarxa ferroviària, entre d'altres, van generar una important caiguda en els costos detransport. Al mateix temps que es donava aquesta progressiva integració del mercat domèstic espanyol, es van produir canvis significatius en la pauta de localització industrial. D'una banda, hi hagué un augment considerable de la concentració espacial de la indústria des de mitjans de segle XIX i fins a la Guerra Civil, i d¿altra, un increment de l'especialització regional. Ara bé, quines van ser les forces que van generar aquests canvis? Des d¿un punt de vista teòric, el model de Heckscher-Ohlin suggereix que la distribució a l'espai de l¿activitat econòmica ve determinada per l'avantatge comparativa dels territoris en funció de la dotació relativa de factors. Al seu torn, els models de Nova Geografia Econòmica (NEG) mostren l'existència d'una relació en forma de campana entre el procés d'integració econòmica i el grau de concentració geogràfica de l'activitat industrial. Aquest article examina empíricament els determinants de la localització industrial a Espanya entre 1856 i 1929, mitjançant l'estimació d¿un model que combina els elements de tipus Heckscher-Ohlin i els factors apuntats des de la NEG, amb l'objectiu de contrastar la força relativa dels arguments vinculats a aquestes dues interpretacions a l'hora de modular la localització de la indústria a Espanya. L'anàlisi dels resultats obtinguts mostra que tant la dotació de factors com els mecanismes de tipus NEG van ser elements determinants que expliquen la distribució geogràfica de la indústria des del segle XIX, tot i que la seva força relativa va anar variant amb el temps.