Factor shares, the price markup, and the elasticity of substitution between capital and labor.

In a Walrasian labor market, the labor income share is constant under the assumptions of a Cobb-Douglas production function and perfect competition. Given the observed decline of the labor share in recent decades, this paper relaxes these assumptions, proposes a time-series calculation of the aggregate price mark-up reflecting the degree of imperfect competition in the product market, and provides estimates of the elasticity of substitution under such product market imperfections. We focus on Spain and the U.S. and show that the elasticity of substitution is above one in Spain and below one in the U.S. We also show that the price markup drives the elasticity of substitution away from one, upwards in Spain, downwards in the U.S. These results are used to explain the declining path of the labor income share, common to both economies, and their contrasted patterns in terms of capital deepening.

Factor shares, the price markup, and the elasticity of substitution between capital and labor

[spa] La participación del trabajo en la renta nacional es constante bajo los supuestos de una función de producción Cobb-Douglas y competencia perfecta. En este artículo se relajan estos supuestos y se investiga si el comportamiento no constante de la participación del trabajo en la renta nacional se explica por (i) una elasticidad de sustitución entre capital y trabajo no unitaria y (ii) competencia no perfecta en el mercado de producto. Nos centramos en España y los U.S. y estimamos una función de producción con elasticidad de sustitución constante y competencia imperfecta en el mercado de producto. El grado de competencia imperfecta se mide a través del cálculo del price markup basado en laaproximación dual. Mostramos que la elasticidad de sustitución es mayor que uno en España y menor que uno en los US. También mostramos que el price markup aleja la elasticidad de sustitución de uno, lo aumenta en España, lo reduce en los U.S. Estos resultados se utilizan para explicar la senda decreciente de la participación del trabajo en la renta nacional, común a ambas economías, y sus contrastadas sendas de capital.

Factor shares, the price markup, and the elasticity of substitution between capital and labor

[spa] La participación del trabajo en la renta nacional es constante bajo los supuestos de una función de producción Cobb-Douglas y competencia perfecta. En este artículo se relajan estos supuestos y se investiga si el comportamiento no constante de la participación del trabajo en la renta nacional se explica por (i) una elasticidad de sustitución entre capital y trabajo no unitaria y (ii) competencia no perfecta en el mercado de producto. Nos centramos en España y los U.S. y estimamos una función de producción con elasticidad de sustitución constante y competencia imperfecta en el mercado de producto. El grado de competencia imperfecta se mide a través del cálculo del price markup basado en laaproximación dual. Mostramos que la elasticidad de sustitución es mayor que uno en España y menor que uno en los US. También mostramos que el price markup aleja la elasticidad de sustitución de uno, lo aumenta en España, lo reduce en los U.S. Estos resultados se utilizan para explicar la senda decreciente de la participación del trabajo en la renta nacional, común a ambas economías, y sus contrastadas sendas de capital.

App Menu Today HTML5

Aplicació web en html5 multi plataforma sense necessitat d'instal·lació. L'aplicació mostrarà una petita xarxa de restaurants al món empresarial per tal de poder gestionar les reserves.

Menu Today

Desenvolupament d'una aplicació web en HTML5 multiplataforma sense necessitat d'instal·lació. L'aplicació mostrarà una petita xarxa de restaurants al món empresarial per tal de poder gestionar les reserves.

The possibility for continuous growth with exhaustible resources: unknowingly an agreement has been reached, but it may not be correct

It is the size of the elasticity of substitution that has been the central issue in the long debate over the possibility of continuous growth in the presence of exhaustible resources. This paper reviews the debate and comes to the surprising conclusion that , unnoticed by the pessimists, the optimist position has gradually evolved so that it now approximates that of the pessimists. The paper also summarises some preliminary work by the author that indicates that this common position may not be correct

Gerogescu-Roegen versus Solow/Stiglitz and the convergence to the Cobb-Douglas

The value of the elasticity of substitution of capital for resources is a crucial element in the debate over whether continual growth is possible. It is generally held that the elasticity has to be at least one to permit continual growth and that there is no way of estimating this outside the range of the data. This paper presents a model in which the elasticity is determined endogenously and may converge to one. It is concluded that the general opinion is wrong: that the possibility of continual growth does not depend on the exogenously given value of the elasticity and that the value of the elasticity outside the range of the data can be studied by econometric methods.

A marxian model of the breakdown of capitalism

This paper sets out a Marxian model that is based on the one by Stephen Marglin with one sector and continuous substitution. It is extended by adding technical progress and land as a factor of production. It is then shown that capital accumulation causes the preconditions for the breakdown of capitalism to emerge; that is, it causes the organic composition of capital to rise, the rate of profit to fall and the rate of exploitation to rise. A compressed history of the idea of the breakdown of capitalism is then set out and an explanation is given as to how the model relates to this and how it may serve as the basis for further research.

Land, technical progress and the falling rate of profit

The paper sets out a one sector growth model with a neoclassical production function in land and a capital-labour aggregate. Capital accumulates through capitalist saving, the labour supply is infinitely elastic at a subsistence wage and all factors may experience factor augmenting technical progress. The main result is that, if the elasticity of substitution between land and the capital-labour aggregate is less than one and if the rate of caital augmenting technical progress is strictly positive, then the rate of profit will fall to zero. The surprise is that this result holds regardless of the rate of land augmenting technical progress; that is, no amount of technical advance in agriculture can stop the fall in the rate of profit. The paper also discusses the relation of this result to the classical and Marxist literature and sets out the path of the relative price of land.

Artificial diets for the production of natural enemies (predators and parasitoids) of greenhouse pest insects

The aim of this contract was to finalise in vitro rearing on artificial diets of entomophagous insects useful to control insect pests mainly in greenhouses through an analytical and rational approach. The work focuses on the development and optimisation of artificial diets for one coccinellid (Harmonia axyridis), two heteropteran predators (Orius laevigatus, Dicyphus tamaninii), and a braconid parasitoid of aphids (Aphidius ervi). The definition of the artificial diets was based on biochemical analyses of their natural food (aphids) or substitution food for the predators (Ephestia kuehniella eggs). Reliable quality control parameters of the entomophages produced were used in order to adjust dietary composition and formulation of the different diets tested.

The Timing of labor demand

We examine the timing of firms' operations in a formal model of labor demand. Merging a variety of data sets from Portugal from 1995-2004, we describe temporal patterns of firms' demand for labor and estimate production-functions and relative labor-demand equations. The results demonstrate the existence of substitution of employment across times of the day/week and show that legislated penalties for work at irregular hours induce firms to alter their operating schedules. The results suggest a role for such penalties in an unregulated labor market, such as the United States, in which unusually large fractions of work are performed at night and on weekends.

Mapa web interactiu de Barcelona

L’objectiu principal d’aquest projecte és crear un sistema que permeti generar i gestionar un mapa de navegació interactiu per a la web i per qualsevol àmbit. Per aconseguir-ho, el projecte està dividit en dos parts: el mapa de navegació i el gestor de continguts. La primera part és una interfície gràfica on hi hauran diferents menús amb les seves categories, cadascuna amb els seus filtres, i per últim, un menú per seleccionar diferents nivells de zoom. El gestor de continguts, la segona part del projecte, és l’eina que permet gestionar via web tots els aspectes relacionats amb la configuració del mapa i la gestió de continguts (menús, punts del mapa, punts d’interès i rutes).

Budget constrained expenditure multipliers

We show that standard expenditure multipliers capture economy-wide effects of new government projects only when financing constraints are not binding. In actual policy making, however, new projects usually need financing. Under liquidity constraints, new projects are subject to two opposite effects: an income effect and a set of spending substitution effects. The former is the traditional, unrestricted, multiplier effect; the latter is the result of expenditure reallocation to upheld effective financing constraints. Unrestricted multipliers will therefore be, as a general rule, upward biased and policy designs based upon them should be reassessed in the light of the countervailing substitution effects.

Effects of increased drought and selective thinning on growth and resprouting of two coexisting Mediterranean oaks with contrasting leaf habit (Quercus ilex and Quercus cerrioides)

According to the IPCC (2007), the Mediterranean basin is expected to suffer important changes in temperature and precipitation in the next few decades, leading the climate warmer and dryer. Therefore, it is necessary to determine the possible effects of increased drought on species with different structural and physiological traits, to be able to predict possible changes in the structure and composition of Mediterranean forests. Moreover, it will be necessary to assess whether traditional management practices can mitigate the effects of climate change on these forests. The main aim of this study has been to analyze the effects of increased drought on the mortality, growth and resprouting patterns of two co-occurring Mediterranean oak species with contrasting leaf habit (the evergreen Quercus ilex and the winter-deciduous Quercus cerrioides), and to assess the effects of selective thinning on their response to increased drought. Our results show a differential effect of increased drought between species: no differences were observed in the growth of Q. ilex while Q. cerrioides reduced its growth under increased drought conditions. Selective thinning reduced the negative effects of increased drought on tree growth, although this beneficial effect tended to decrease during the experiment. Our results show that increasing aridity in Mediterranean areas can be a constraining factor for deciduous oaks, thus potentially causing their decline in mixed forests and favouring their substitution by the evergreen congeneric species. However, as seen in this study, management can strongly encourage growth both for deciduous and evergreen species, thus reversing the effects of increased water stress on Mediterranean coppices.

Els cultius in vitro i el desenvolupament vegetal

Biotecnologia Vegetal de materials de treball que incorporin les TICs. El material elaborat ha estat un llibre electrònic utilitzable tant on-line (web) com off-line (CD). Els materials generats com a resultes d’aquest projecte han estat situats en un servidor de la UdL accessible des de l’exterior de la Universitat. Aquest llibre electrònic és d’accés obert i es pot consultar on-line a l’URL (http://sakai.udl.es/cursos/76304/indexC.htm). El llibre electrònic conté un total de 98 Mb d’informació hipermèdia i hipertexual distribuïda en més de 380 arxius dels quals 50 són pàgines html, 10 arxius doc, 10 arxius pdf, 258 imatges fixes i 8 arxius de vídeo en format flash (swf). L’accés al llibre electrònic es realitza a través d’una pantalla inicial que dóna pas a un menú que distribueix els materials en 7 apartats. Els textos estan acompanyats de gran quantitat d’imatges fotogràfiques, gràfics, esquemes, imatges infogràfiques i videoclips generats de novo per aquest projecte. En dissenyar la web s’han tingut en compte criteris de confiabilitat, accessibilitat i usabilitat. El primer disseny de la web ha estat validat per un panel d’usuaris i utilitzat posteriorment amb alumnes durant el curs 2007-2008. Les observacions i suggeriments fets per aquests ja han estat incorporats en aquest document final. Una primera enquesta de satisfacció realitzada amb aquest alumnat permet concloure, a títol provisional donat lo reduït de la població enquestada, que l’alumnat mostra un grau de coneixement de les eines TIC suficient i que consideren positiva la incorporació de materials multimèdia com a recurs educatiu. A més a més, la realització d’aquest projecte i la seva aplicació a l’aula ha estat presentada en dues ponències al “Congreso Internacional de Docencia y Innovación Universitaria”.