Labor demand and information technologies: evidence for Spain, 1980-2005

Utilizando la base de datos EU KLEMS, se contrasta la hipótesis de complementariedad entre habilidad y capital en los distintos sectores productivos en España en el periodo 1980-2005. Se analizan tres tipos de trabajadores clasificados según su nivel de habilidad sea alto, medio o bajo. Los activos de capital se van a clasificar entre activos TIC (tecnologías de la información y la comunicación) y activos no-TIC. La adquisición y el uso de activos TIC son costosos pero ha ido disminuyendo en el periodo en consideración en términos relativos a otros activos y al factor trabajo. El principal resultado que se obtiene es que existe un grado de sustituibilidad entre los trabajadores y los activos TIC a medida que la habilidad del trabajador va aumentando. De hecho, los activos TIC son muy complementarios con los trabajadores de alta habilidad. A lo largo del periodo analizado, la fracción de trabajadores con habilidad media y alta ha crecido un 21% y un 12%, respectivamente, en detrimento de los trabajadores de baja habilidad. Después de descomponer estos cambios, se descubre que existe un ajuste dentro de los sectores más que un ajuste del trabajo entre sectores.capital-skill complementarity, ICT, translog cost function, elasticity of substitution.

Labor Demand and Information Technologies: Evidence for Spain, 1980-2005

Using the EU KLEMS dataset we test the capital-skill complementarity hypothesis in a cross-section of sectors in Spain between 1980 and 2005. We analyze three groups of workers, who are classed according to skill level: high, medium and low. Capital assets have been broken down into ICT (information and communication technologies) assets and non-ICT assets. Acquisition and usage costs of ICT assets declined throughout the period studied, both in absolute terms and relative to the other capital assets and workers. Our principal finding is that the substitutibility between workers and ICT assets falls as worker skill level rises. In fact, the ICT assets were strongly complement with highly skilled workers and were not substitutive with them. Throughout the period analyzed, the fraction of employed medium- and high-skill workers rose by 21% and 12%, respectively, to the disadvantage of low-skill workers. After decomposing these changes, we found that the latter were dominated by an ajustment within sectors more than by a composition effect or adjustment between sectors. These adjustments may be explained by reference to the estimated elasticities of substitution.capital-skill complementarity, ICT, translog cost function, elasticity of substitution.

H-Galois extensions with normal basis for weak Hopf algebras

Let H be a weak Hopf algebra and let A be an H-comodule algebra with subalgebra of coinvariants AH. In this paper we introduce the notion of H-Galois extension with normal basis and we prove that AH ,→ A is an H-Galois extension with normal basis if and only if AH ,→ A is an H-cleft extension which admits a convolution invertible total integral. As a consequence, if H is cocommutative and A commutative, we obtain a bijective correspondence between the second cohomology group H2 ϕAH (H, AH) and the set of isomorphism classes of H-Galois extensions with normal basis whose left action over AH is ϕAHThis work was supported by Ministerio de Economía y Competitividad and by Feder founds. Grant MTM2013-43687-P: Homología, homotopía e invariantes categóricos en grupos y álgebras no asociativasS

Mergeable weighted majority games and characterizations of some power indices

In this paper, we introduce a notion of mergeable weighted majority games with the aim of providing the first characterization of the Colomer–Martínez power index (Colomer and Martínez in J Theor Polit 7(1):41–63, 1995). Furthermore, we define and characterize a new power index for the family of weighted majority games that combines ideas of the Public Good (Holler in Polit Stud 30(2):262–271, 1982) and Colomer–Martínez power indices. Finally, we analyze the National Assembly of Ecuador using these and some other well-known power indicesWe would like to thank Balbina V. Casas-Méndez and two anonymous referees for their valuable comments. This work is part of the R+D+I project grants MTM2017-87197-C3-2-P, MTM2017-87197-C3-3-P, PID2021-124030NB-C32, and PID2021-124030NB-C33, that were funded by MCIN/AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”/EU. This research was also funded by Grupos de Referencia Competitiva ED431C-2020/03 and ED431C-2021/24 from the Consellería de Cultura, Educación e Universidades, Xunta de Galicia. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NatureS

Weak C-cleft extensions, weak entwining structures and weak Hopf algebras

En este artigo formúlase a noción de extensión cleft feble para unha estructura entrelazante feble nunha categoría monoidal trenzada C. Próbase que, dada unha extensión deste tipo, se obtén unha xeneralización dun produto semidirecto a este contexto. Estes resultados permiten obter versións para álxebras de Hopf febles de resultados clásicos de álxebras de Hopf, como o teorema de Radford para álxebras de Hopf febles con proxección.The authors would like to thank the referee for his constructive and interesting comments. The authors have been supported by Ministerio de Ciencia y Tecnología, by Xunta de Galicia and by FEDER, Projects: BFM2003-07353-C02-01, BFM2003-07353-C02-02, PGIDITO4PXIC32202PN, PGIDITO4PXIC20703PN.S

Los materiales de cambio de fase en las granjas y en los establos

Se analizan las condiciones climáticas que se requieren en las granjas de aves, en particular: temperatura, velocidades de aire, humedad, renovaciones de aire, en función del tipo de aves: pollos de engorde, ponedoras y para carne. Se revisan los tipos de granjas de aves más empleados y se establecen los sistemas de calefacción y climatización más usados en particular los de enfriamiento evaporativo. Se discuten los peligros más graves que tienen las granjas de aves debido a las temperaturas y las humedades.Se analizan los materiales de cambio de fase (PCM), en particular los que se consideran idóneos para su empleo en la climatización de granjas para aves. Por último se describen posibles soluciones para la climatización de granjas de aves empleando los PCM, concluyendo con un análisis de sus ventajas.Peer reviewe

Transporte de pescado con materiales de cambio de fase

Se analiza la pesca en España, planteando algunos de sus problemas como el derivado de la normativa de la Comunidad Europea, sobre la comercialización y el transporte del pescado y marisco con agua y hielo, y se proponen algunas soluciones, como es el empleo de mezclas eutécticas en bolsas o recipientes estancos. Figura 1

Crossed Products in Weak Contexts

his version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s10485-008-9139-2We define the general notion of crossed products in a weak context, which generalizes the ones defined by Blattner, Cohen and Montgomery, Doi and Takeuchi in the context of Hopf algebras and the one given by Brzezin´ ski. Also, the crossed products obtained by the authors, for weak Hopf algebras living in a symmetric monoidal category and weak C-cleft extensiMinisterio de Educación, proxectos MTM2007-62427, MTM2006-14908-CO2-01. Xunta de Galicia, proxecto PGIDT07PXB32-2079PR.S

Determination of the glass-forming concentration range in binary alloys from a semiempirical theory: Application to Zr-based alloys

Producción CientíficaA semiempirical theory is presented to calculate free-energy diagrams of glass-forming alloys. The theory is based on the enthalpy of formation of the solid solution expressed as a sum of two contributions: (a) a chemical contribution due to electronic redistribution in forming the alloy, and (b) an elastic contribution arising from the difference in size between solute and solvent atoms. The enthalpy of formation of the amorphous phase has only the chemical contribution. The theory is used to successfully describe the glass-forming concentration range of some Zr-based alloys, which have been experimentally analyzed by several distinct techniques