Big plant closures and agglomeration economies

This paper analyses the effects of large manufacturing plant closures on local employment. Specifically, we estimate the net employment effects of the closure of 45 large manufacturing plants in Spain, which relocated abroad between 2001 and 2006. We run differences-in-differences specifications in which locations that experience a closure are matched to locations with similar pre-treatment employment levels and trends. The results show that when a plant closes, for each job directly lost in the plant closure, between 0.3 and 0.6 jobs are actually lost in the local economy. The adjustment is concentrated in incumbent firms in the industry that suffered the closure, providing indirect evidence of labor market pooling effects. We find no employment effects in the rest of manufacturing industries or in the services sectors. These findings suggest that traditional input-output analyses tend to overstate the net employment losses of large plant closures

Valorization of tannery wastes: Lipoamino acid surfactant mixtures from the protein fraction of process wastewater

The first stages of the transformation process of hides into leather (beamhouse process) generate an important waste in the tanning industry, since a considerable fraction of solubilized proteins ends up in waste water with the corresponding increase in contamination parameters, especially when the process is carried out without hair recovery (hair-pulping process). The objective of this work was the valorisation of this waste (the separated protein fraction) which conveniently hydrolyzed to amino acid level constituted the starting material for the production of biodegradable surfactants. The lipoamino acid surfactants were obtained by acylation of the amino acids from the protein hydrolysate. These surfactants were characterized and their physico-chemical and biological properties evaluated. They exhibit very low cmc values (about 40. mg/L). These surfactants are readily biodegradable and present an aquatic toxicity significantly lower than many common commercial surfactants derived whether from renewable or petrochemical feedstock. The mixtures of surfactants obtained are able to form oil/water emulsions that remain stable for at least 1. year. The results obtained in this work confirmed that it is possible the production of biodegradable and efficient lipoamino acid surfactant mixtures from the protein fraction present in beamhouse process wastewaters. This study constitutes a promising approach for the reduction of the pollution load from industrial tannery wastes and its valorisation as raw material for the production of surfactants with excellent environmental properties and good technical properties.The authors are grateful to the Spanish Ministry of Economy and Competitiveness for the financial support given through the CTQ2013-41514P, CTQ2013-43029P and MAT2012-38047-C02-02 Projects.Peer reviewe

Sequential city growth in the US: does age matter?

We provide empirical evidence of the dynamics of city size distribution for the whole of the twentieth century in U.S. cities and metropolitan areas. We focus our analysis on the new cities that were created during the period of analysis. The main contribution of this paper, therefore, is the parametric and nonparametric analysis of the population growth experienced by these new-born cities. Our results enable us to confirm that, when cities appear, they grow very rapidly and, as the decades pass, their growth slows or even falls into decline. This is consistent with the theoretical framework regarding mean reversion (convergence) in the steady state and with the theories of sequential city growth

Big plant closures and local employment

This paper estimates the impact of large plant closures on the local employment in the affected industry. Specifically, we examine the closure of 45 large manufacturing plants in Spain which relocated abroad between 2001 and 2006. We run differences-in-differences specifications in which locations that experience a closure are matched to locations with similar pre-treatment employment levels and trends. The results show that when a plant closes, for each job directly lost in the plant closure, only between 0.6 and 0.7 jobs are actually lost in the local affected industry. These effects are driven by employment expansions in local incumbent firms and, to a lesser extent, by the creation of new firms in the local industry

Polarized cortical tension drives zebrafish epiboly movements

The principles underlying the biomechanics of morphogenesis are largely unknown. Epiboly is an essential embryonic event in which three tissues coordinate to direct the expansion of the blastoderm. How and where forces are generated during epiboly, and how these are globally coupled remains elusive. Here we developed a method, hydrodynamic regression (HR), to infer 3D pressure fields, mechanical power, and cortical surface tension profiles. HR is based on velocity measurements retrieved from 2D+T microscopy and their hydrodynamic modeling. We applied HR to identify biomechanically active structures and changes in cortex local tension during epiboly in zebrafish. Based on our results, we propose a novel physical description for epiboly, where tissue movements are directed by a polarized gradient of cortical tension. We found that this gradient relies on local contractile forces at the cortex, differences in elastic properties between cortex components and the passive transmission of forces within the yolk cell. All in all, our work identifies a novel way to physically regulate concerted cellular movements that might be instrumental for the mechanical control of many morphogenetic processes.Peer ReviewedPostprint (author's final draft

Proteomics: a poweful tool to deepen the molecular mechanisms of ischemic stroke

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