Spatial distribution of economic activities: an empirical approach usingself-organizing maps

The aim of this paper is to analyse the colocation patterns of industries and firms. We study the spatial distribution of firms from different industries at a microgeographic level and from this identify the main reasons for this locational behaviour. The empirical application uses data from Mercantile Registers of Spanish firms (manufacturers and services). Inter-sectorial linkages are shown using self-organizing maps. Key words: clusters, microgeographic data, self-organizing maps, firm location JEL classification: R10, R12, R34

Quantifying rock fabrics: a test of autocorrelation of the spatial distribution of cristals

A novel test of spatial independence of the distribution of crystals or phases in rocksbased on compositional statistics is introduced. It improves and generalizes the commonjoins-count statistics known from map analysis in geographic information systems.Assigning phases independently to objects in RD is modelled by a single-trial multinomialrandom function Z(x), where the probabilities of phases add to one and areexplicitly modelled as compositions in the K-part simplex SK. Thus, apparent inconsistenciesof the tests based on the conventional joins{count statistics and their possiblycontradictory interpretations are avoided. In practical applications we assume that theprobabilities of phases do not depend on the location but are identical everywhere inthe domain of de nition. Thus, the model involves the sum of r independent identicalmultinomial distributed 1-trial random variables which is an r-trial multinomialdistributed random variable. The probabilities of the distribution of the r counts canbe considered as a composition in the Q-part simplex SQ. They span the so calledHardy-Weinberg manifold H that is proved to be a K-1-affine subspace of SQ. This isa generalisation of the well-known Hardy-Weinberg law of genetics. If the assignmentof phases accounts for some kind of spatial dependence, then the r-trial probabilitiesdo not remain on H. This suggests the use of the Aitchison distance between observedprobabilities to H to test dependence. Moreover, when there is a spatial uctuation ofthe multinomial probabilities, the observed r-trial probabilities move on H. This shiftcan be used as to check for these uctuations. A practical procedure and an algorithmto perform the test have been developed. Some cases applied to simulated and realdata are presented.Key words: Spatial distribution of crystals in rocks, spatial distribution of phases,joins-count statistics, multinomial distribution, Hardy-Weinberg law, Hardy-Weinbergmanifold, Aitchison geometry

Technology diffusion and the spatial distribution of wages in the US

What explains the spatial distribution of wages across US counties? I find that two of the most important factors are spatial technology diffusion and externalities due to the aggregate scale of production. One empirical finding supporting the importance of spatial technology diffusion is that average wages in a county decrease with the average level of schooling in neighboring counties when employment in the county and average wages in neighboring counties are held constant. All empirical results are obtained using anovel instrument for (endogenous) employment at the county-leveland take into account other factors (e.g. productivity-differencesacross states, climate) that may determine wages.

Spatial distribution and biomass of aquatic rooted macrophytes and their relevance in the metabolism of a Mediterranean coastal lagoon

This work aims to characterise the current autotrophic compartment of the Albufera des Grau coastal lagoon (Menorca, Balearic Islands) and to assess the relationship between the submerged macrophytes and the limnological parameters of the lagoon. During the study period the submerged vegetation was dominated by the macrophyte Ruppia cirrhosa, which formed dense extensive meadows covering 79% of the surface. Another macrophyte species, Potamogeton pectinatus, was also observed but only forming small stands near the rushing streams. Macroalgae were only occasionally observed. Macrophyte biomass showed a clear seasonal trend, with maximum values in July. The biomass of R. cirrhosa achieved 1760 g DW m-2, the highest biomass ever reported for this species in the literature. The seasonal production-decomposition cycle of the macrophyte meadows appears to drive the nutrient dynamics and carbon fluxes in the lagoon. Despite the significant biomass accumulation and the absence of a washout of nutrients and organic matter to the sea, the lagoon did not experience a dystrophic collapse. These results indicate that internal metabolism is more important than exchange processes in the lagoon.

Evaluation of spatial distribution of flatfish by laser scannig

Peer reviewed

The Spatial Distribution of Spanish Transport Infrastructure between 1860 and 1930

The origin of Spanish regional economic divergence can be traced back at least until the seventeenth century, although its full definition took place during industrialisation. Historians have often included uneven regional infrastructure endowments among the factors that explain divergence among Spanish regions, although no systematic analysis of the spatial distribution of Spanish infrastructure and its determinants has been carried out so far. This paper aims at filling that gap, by offering a description of the regional distribution of the main Spanish transport infrastructure between the middle of the nineteenth century and the Civil War. In addition, it estimates a panel data model to search into the main reasons that explain the differences among the Spanish regional endowments of railways and roads during that period. The outcomes of that analysis indicate that both institutional factors and the physical characteristics of each area had a strong influence on the distribution of transport infrastructure among the Spanish regions.

The Spatial Distribution of Human Capital: Can It Really Be Explained by Regional Differences in Market Access?

This paper tests the robustness of estimates of market access impact on regional variability in human capital, as previously derived in the NEG literature. Our hypothesis is that these estimates of the coefficient of market access, in fact, capture the effects of regional differences in the industrial mix and the spatial dependence in the distribution of human capital. Results for the Spanish provinces indicate that the estimated impact of market access vanishes and becomes non-significant once these two elements are included in the empirical analysis.

Agonistic strategies and spatial distribution in captive sooty mangabeys (Cercocebus atys lunulatus)

The aim of this article is to study the relationship between the dominance hierarchy and the spatial distribution of a group of captive sooty mangabeys (Cercocebus atys). The analysis of the spatial distribution of individuals in relation to their rank in the dominance hierarchy showed a clear linear hierarchy in which the dominant individual was located in central positions with regard to the rest of the group members. The large open enclosure where the group was living allowed them to adopt a high-risk agonistic strategy in which individuals attacked other individuals whose rank was significantly different from their own. The comparison of the results with a previous study of mangabeys showed that, although the dominance ranks of both groups were similar, the fact that they lived in facilities with different layouts caused different agonistic strategies to emerge and allowed the dominant individual to assume different spatial locations.

Inventors on the move: tracing inventors’ mobility and its spatial distribution

This paper aims to provide insights into the phenomenon of knowledge flows. We study one of the main mechanisms through which these flows occur, i.e., the mobility of highly-skilled individuals. We focus on the geographical mobility of inventors across European regions. Thus, patent data are used to trace the pattern of inventors’ mobility across european regions, to track down focuses of attraction of talent throughout the continent, and to study their distribution across the space. To do so, we gather information from PCT patent documents and we first match the names which seemed to belong to the same inventor and then we create a new algorithm to decide whether each patent applied for under each name belongs to the same inventor.

Distribution Patterns of Soil Properties in a Rural Mediterranean Area in Northeastern Spain

Soil properties on the Cap de Creus Peninsula, NE Spain depend primarily on scarce agricultural practices and early abandonment. In the study area, 90% of which is mainly covered by Cistus shrubs, 8 environments representing variations in land use/land cover and soil properties at different depths were identified. In each environment variously vegetated areas were selected and sampled. The soils, collected at different depths, were classified as Lithic Xerorthents according to the United States Department of Agriculture system of soil classification (USDA-NRCS 1975). Differences in soil properties were largely found according to the evolution of the plant canopy and the land use history. To identify underlying patterns in soil properties related to environmental evolution, factor analysis was performed and factor scores were used to determine how the factor patterns varied between soil variables, soil depths and selected environments. The three-factor model always accounted for 80% of the total variation in the data at the different soil depths. Organic matter was the more relevant soil property at 0–2 cm depth, whereas active minerals (silt and clay) were found to be the most relevant soil parameters controlling soil dynamics at the other depths investigated. Results showed that vineyards and olive tree soils are poorly developed and present worse conditions for mineral and organic compounds. Analysis of factor scores allowed independent assessment of soils, depth and plant cover and demonstrated that soils present the best physico-chemical characteristics under Erica arborea and meadows. In contrast, soils under Cistus monspeliensis were less nutrient rich and less well structured

The spatial inequality of wage income in Barcelona Metropolitan Area

ABSTRACT The measure and estimation of income levels in Barcelona Metropolitan Area (BMA) goes back a long way. Using different approaches and focusing on different municipalities, there is a lot of work in the field. The majority of the literature has focused on the estimation of income levels using variables related to consumption. The empirical evidence on wage differentials has shown an important growth during 80’s and 90’s especially in United Kingdom and USA. Less is known on spatial distribution of inequality. This paper presents a new data set for analyzing spatial distribution of wage income. This data is obtained by matching Wage Structure Survey (WSS) with data from Census disaggregated by census tracts. In this way we have a unique data set with wage incomes for every census track for 36 municipalities belonging to BMA. We develop a descriptive analysis of spatial distribution, testing for spatial autocorrelation and use the family of Generalised Entropy Indices to measure inequality. Properties of the index allow us to decompose inequality into inter and intra-municipality measures. Since we have two cross-sectional data for WSS (1995-2002) we can also analyze the evolution of the inequality in this period of economic growth. Key words: spatial distribution of wages, spatial autocorrelation, inequality indices.

Estràtegies de gestió per al manteniment de la biodiversitat a la sabana brasilera: control d'especies exòtiques amb foc

Report for the scientific sojourn at the Instituto de Biociências, of the Universidade de Sao Paulo, Brazil, from 2007 to 2009. African exotic grasses, used as forage crops for cattle, found optimal conditions in Brazilian savannas for their spread. They established as invasive grasses in almost all conservation units, becoming a serius threat to native biote and to most ecological processes. Fire is a cyclical event in Brazilian savannas and can be used as a management tool for enhancing competitivity of native grasses and controlling exotic grasses. Seeking for alternatives for the management of these grasses, this study investigates the effect of recurrent burnings in different periods of the year (fire regimes) on: distribution patterns of exotic grasses and their associations wotih native grasses, the local edaphic characteristics, the nutrient pool of the aerial biomass of both native and exotic grasses, and soil seed banks. This project is held on the IBGE Ecological Reserve, in Brasília (Brazil), in an area destined specifically for research of fire effects on brazilian savannas. The project quantifies: aerial biomass of native and exotic grasses, soil seed bank of exotic grasses, nutrient pool in soil and also in grasses tissues. Spatial relationships for any association between species, as well as for nutrient pools in soil and in plant tissues will be established. A better understanding of these processes will provide useful tools for adopting specific policies on the management of exotic grasses in Brazilian savanna.

Spatial variability of tree hight at treeline ecotones in the Pyrenees.

We describe the spatial distribution of tree height of Pinus uncinata at two undisturbed altitudinal treeline ecotones in the southern Pyrenees (Ordesa, O, and Tessó, T). At each site, a rectangular plot (30 x 140 m) was located with its longest side parallel to the slope and encompassing treeline and timberline. At site O, height increased abruptly going downslope with a high spatial autocorrelation at short distances. In contrast, the changes of tree height across the ecotone at site T were gradual, and tree height was less spatially autocorrelated. These results can be explained by the greater importance of wind and snow avalanches at sites O and T, respectively.

Nuevas técnicas de estadística espacial para la detección de clusters residenciales de población inmigrante

La estadística aplicada a la geografía ha experimentado un avance espectacular en las últimas dos décadas introduciéndose el espacio como eje fundamental del análisis. Este avance se ha visto acompañado por un rápido desarrollo de aplicaciones estadísticas integradas en los sistemas de información geográfica, constituyéndose de esta forma en un conjunto de herramientas imprescindibles en la planificación territorial. Por otro lado, en España, el incremento de población inmigrada en un corto intervalo de tiempo ha hecho necesario analizar su distribución espacial en las áreas urbanas. Los índices de autocorrelación espacial, tanto global como local, y su representación cartográfica constituyen una técnica adecuada para la detección de clusters y patrones espaciales y abre la posibilidad de plantear diferentes modelos econométricos. A partir del caso de la ciudad de Barcelona se aplican las técnicas descritas y se observan los diferentes comportamientos según el grupo de población estudiado.

Comparison between land suitability and actual crop distribution in an irrigation district of the Ebro valley (Spain)

El objetivo de la presente investigación fue analizar la correspondencia entre los resultados de una evaluación de tierras con la distribución real de los cultivos. Para ello la aptitud biofísica de las tierras se comparó con diferentes tipologías de frecuencia de ocurrencia de los cultivos y rotaciones derivadas de mapas de cultivos multitemporales. La investigación fue llevada a cabo en el distrito de riego de Flumen (33.000 ha), localizado en el valle del Ebro (NE España). La evaluación de tierras se basó en una cartografía de suelos 1:100.000, según el esquema FAO, para los principales cultivos presentes en el área de estudio (alfalfa, cereales de invierno, maíz, arroz y girasol). Se utilizaron tres mapas de frecuencia de cultivos y un mapa de rotaciones, derivado de una serie temporal de imágenes Landsat TM y ETM+ del periodo 1993-2000, y se compararon con los mapas de aptitud de tierras para los diferentes cultivos. Se analizó estadísticamente (Pearson χ2, Cramer V, Gamma y Somers D) la relación entre los dos tipos de variables. Los resultados muestran la existencia de una relación significativa (P=0,001) entre la localización de los cultivos y la idoneidad de las tierras, excepto de cultivos oportunistas como el girasol, muy influenciado por las subvenciones en el periodo estudiado. Las rotaciones basadas en la alfalfa muestran los mayores porcentajes (52%) de ocupación en las tierras más aptas para la agricultura en el área de estudio. El presente enfoque multitemporal de análisis de la información ofrece una visión más real que la comparación entre un mapa de evaluación de tierras y un mapa de cultivos de una fecha determinada, cuando se valora el grado de acuerdo entre las recomendaciones sobre la aptitud de las tierras y los cultivos realmente cultivados por los agricultores.