SKILL POLARIZATION IN LOCAL LABOR MARKETS UNDER SHARE‐ALTERING TECHNICAL CHANGE

This paper considers the “share‐altering” technical change hypothesis in a spatial general equilibrium model where individuals have different levels of skills. Building on a simple Cobb‐Douglas production function, our model shows that the implementation of skill‐biased technologies requires a sufficient proportion of highly educated individuals. Moreover, when technical progress disproportionately replaces middle‐skill jobs, the local distribution of skills will exhibit “fat‐tails,” where the proportion of both highly skilled and low‐skilled workers increases. These and several other predictions of the model are consistent with recent existing evidence, and avoid some major criticism against the “canonical” CES framework.     

Isotopic Composition of Lead in Copper Ores and a Copper Artefact from the La Profunda Mine (León,Spain)

This paper continues the characterization of the lead isotopic fingerprint of ancient copper mines in the north‐west of Spain. In this work, the lead isotopic compositions found in copper ores from the La Profunda mine are presented. Azurites and malachites sampled from this deposit were subjected to lead isotope analysis by multicollector ICP–MS. The results showed a clear radiogenic lead signature compatible with the presence of uranium‐rich minerals (such as zeunerite) in the same mining complex. Moreover, a rare copper artefact, found in the galleries of the mine during its modern exploitation, was also analysed and showed that local mineral was used for its manufacturing.     

Identification of Employment Concentration Areas

This article presents a method to identify “Absolute and Relative Employment Concentration (AREC) areas” for a particular industry. Two novel characteristics of the method are that it simultaneously analyses AREC, and that it combines spatial concentration per area with the spatial concentration in neighbouring areas. The method is easy to understand and apply. It is developed to assist regional policy makers and corporate decision-makers with their investment decisions related to new infrastructure or plants. The identification of concentration areas also allows for analysing the performance of these areas in relation to characteristics such as infrastructure availability and the housing and labour market. This can yield new academic insights that are relevant for regional planners. An application of the newly developed method to five industries in a Dutch province subdivided into 502 areas illustrates the value of the method in comparison to other methods.     

Philosophy as a cultural resource and medium of reflection for Hermann Weyl

In a talk given at Zurich in the late 1940s, Hermann Weyl discussed Ferdinand Gonseth's dialectical epistemology and considered it as being restricted too strictly to aspects of historical change. His experiences with post-Kantian dialectical philosophy, in particular Johann Gottlieb Fichte's derivation of the concept of space and matter, had been a stronger dialectical background for his own 1918 studies in purely infinitesimal geometry and the early geometrically unified field theory of matter (extending the Mie-Hilbert program). Although now Weyl distantiated himself from the speculative features of his youthful philosophizing and in particular from his earlier enthusiasm for Fichte, he again had deep doubts as to the cultural foundations of modern mathematical sciences and its role in material culture of high modernity. For Weyl, philosophical «reflection» was a cultural necessity he now turned towards Karl Jaspers' and Martin Heidegger's existentialism to find deeper grounds, similar to his turn towards Fichte's philosophy after World War I. The discussion in the late 1940s can be read as a kind of post-World-War-II «Nachtrag» to Weyl's more widely known philosophical comments on mathematics and the natural sciences published in the middle of the 1920s.     

Bridge the Gap: From Spatial Planning to Strategic Projects

This paper introduces one of the largest single research projects ever granted in the field of spatial planning. It presents the context the project has to work in and the challenges it has to face. It further gives a broad outline of the research project, with three horizontal and three vertical tracks and some success indicators.     

Use of robust methods to determine quadratic surfaces: application to heritage

3D surveys of archaeological elements and the construction of virtual models enable us to reconstruct historical sites. They provide useful data to select specific building processes.Photogrammetry and Terrestrial Laser Scanning (TLS) are the most common techniques to obtain synthetically heritage models. These techniques provide massive data which can only be managed by replacing them by primitive shapes, thereby obtaining more simple models and the explicit geometry of the element. Statistical and robust methods are used for this substitution, thereby avoiding the common errors due to measuring. Of these methods, the most widely used are the least-median-of-squares (LMedS) and the RANSAC method.Another computation method consists in recursive processes based on evolutive-type algorithms to adjust the model to the data captured.This paper describes two surface computation methodologies to determine the modelling of a column shaft located in temple G of the archaeological park of Selinunte (Sicily).