Elicited bid functions in (a)symmetric first-price auctions

We report on a series of experiments that examine bidding behavior in first-price sealed bid auctions with symmetric and asymmetric bidders. To study the extent of strategic behavior, we use an experimental design that elicits bidders' complete bid functions in each round (auction) of the experiment. In the aggregate, behavior is consistent with the basic equilibrium predictions for risk neutral or homogenous risk averse bidders (extent of bid shading, average seller's revenues and deviations from equilibrium). However, when we look at the extent of best reply behavior and the shape of bid functions, we find that individual behavior is not in line with the received equilibrium models, although it exhibits strategic sophistication.

Towards an emotion-driven interactive music system: ridging the gaps between affect, physiology and sound generation

Report for the scientific sojourn at the Stanford University from January until June 2007. Music is well known for affecting human emotional states, yet the relationship between specific musical parameters and emotional responses is still not clear. With the advent of new human-computer interaction (HCI) technologies, it is now possible to derive emotion-related information from physiological data and use it as an input to interactive music systems. Providing such implicit musical HCI will be highly relevant for a number of applications including music therapy, diagnosis, nteractive gaming, and physiologically-based musical instruments. A key question in such physiology-based compositions is how sound synthesis parameters can be mapped to emotional states of valence and arousal. We used both verbal and heart rate responses to evaluate the affective power of five musical parameters. Our results show that a significant correlation exists between heart rate and the subjective evaluation of well-defined musical parameters. Brightness and loudness showed to be arousing parameters on subjective scale while harmonicity and even partial attenuation factor resulted in heart rate changes typically associated to valence. This demonstrates that a rational approach to designing emotion-driven music systems for our public installations and music therapy applications is possible.

GAPS: generador de aplicaciones sintéticas

Gaps es un generador de aplicaciones sintéticas de estructura compuesta Master/Worker de pipelines. Para crear una aplicación sintética, el investigador utilizará Gaspar, que recibe un fichero de texto con los parámetros de la aplicación a generar: cantidad de workers, etapas, tamaño de mensaje a enviar, etc., y genera un fichero con las propiedades de cada etapa. A partir de estos datos, Gaps, que esta hecho en C con MPI, genera y ejecuta la aplicación paralela. Estas aplicaciones se utilizan para comprobar en un entorno real los estudios analíticos que constituyen el modelo de rendimiento y sintonización dinámica.

Symmetric planar central configurations of five bodies: Euler plus two

We study planar central configurations of the five-body problem where three of the bodies are collinear, forming an Euler central configuration of the three-body problem, and the two other bodies together with the collinear configuration are in the same plane. The problem considered here assumes certain symmetries. From the three bodies in the collinear configuration, the two bodies at the extremities have equal masses and the third one is at the middle point between the two. The fourth and fifth bodies are placed in a symmetric way: either with respect to the line containing the three bodies, or with respect to the middle body in the collinear configuration, or with respect to the perpendicular bisector of the segment containing the three bodies. The possible stacked five-body central configurations satisfying these types of symmetries are: a rhombus with four masses at the vertices and a fifth mass in the center, and a trapezoid with four masses at the vertices and a fifth mass at the midpoint of one of the parallel sides.

On Strategy-proofness and symmetric single-peakedness

We characterize the class of strategy-proof social choice functions on the domain of symmetric single-peaked preferences. This class is strictly larger than the set of generalized median voter schemes (the class of strategy-proof and tops-only social choice functions on the domain of single-peaked preferences characterized by Moulin (1980)) since, under the domain of symmetric single-peaked preferences, generalized median voter schemes can be disturbed by discontinuity points and remain strategy-proof on the smaller domain. Our result identifies the specific nature of these discontinuities which allow to design non-onto social choice functions to deal with feasibility constraints.

A model structure for coloured operads in symmetric spectra

We describe a model structure for coloured operads with values in the category of symmetric spectra (with the positive model structure), in which fibrations and weak equivalences are defined at the level of the underlying collections. This allows us to treat R-module spectra (where R is a cofibrant ring spectrum) as algebras over a cofibrant spectrum-valued operad with R as its first term. Using this model structure, we give sufficient conditions for homotopical localizations in the category of symmetric spectra to preserve module structures.

Are the maximum hardness and minimum polarizability principles always obeyed in nontotally symmetric vibrations?

An overview is given on a study which showed that not only in chemical reactions but also in the favorable case of nontotally symmetric vibrations where the chemical and external potentials keep approximately constant, the generalized maximum hardness principle (GMHP) and generalized minimum polarizability principle (GMPP) may not be obeyed. A method that allows an accurate determination of the nontotally symmetric molecular distortions with more marked GMPP or anti-GMPP character through diagonalization of the polarizability Hessian matrix is introduced

Markups, Gaps, and the Welfare Costs of Business Fluctuations

In this paper we present a simple theory-based measure of the variations in aggregate economic efficiency: the gap between the marginal product of labor and the household s consumption/leisure tradeoff. We show that this indicator corresponds to the inverse of the markup of price over social marginal cost, and give some evidence in support of this interpretation. We then show that, with some auxilliary assumptions our gap variable may be used to measure the efficiency costs of business fluctuations. We find that the latter costs are modest on average. However, to the extent the flexible price equilibrium is distorted, the gross efficiency losses from recessions and gains from booms may be large. Indeed, we find that the major recessions involved large efficiency losses. These results hold for reasonable parameterizations of the Frisch elasticity of labor supply, the coefficient of relative risk aversion, and steady state distortions.

Gender gaps in performance: Evidence from young lawyers

This paper documents and studies the gender gap in performance among associatelawyers in the United States. Unlike most high-skilled professions, the legal professionhas widely-used objective methods to measure and reward lawyers' productivity: thenumber of hours billed to clients and the amount of new-client revenue generated. Wefind clear evidence of a gender gap in annual performance with respect to bothmeasures. Male lawyers bill ten-percent more hours and bring in more than double thenew-client revenue. We show that the differential impact across genders in the presenceof young children and the differences in aspirations to become a law-firm partneraccount for a large part of the difference in performance. These performance gaps haveimportant consequences for gender gaps in earnings. While individual and firmcharacteristics explain up to 50 percent of earnings gap, the inclusion of performancemeasures explains most of the remainder.

Unfolding a symmetric matrix

Graphical displays which show inter--sample distances are importantfor the interpretation and presentation of multivariate data. Except whenthe displays are two--dimensional, however, they are often difficult tovisualize as a whole. A device, based on multidimensional unfolding, isdescribed for presenting some intrinsically high--dimensional displays infewer, usually two, dimensions. This goal is achieved by representing eachsample by a pair of points, say $R_i$ and $r_i$, so that a theoreticaldistance between the $i$-th and $j$-th samples is represented twice, onceby the distance between $R_i$ and $r_j$ and once by the distance between$R_j$ and $r_i$. Self--distances between $R_i$ and $r_i$ need not be zero.The mathematical conditions for unfolding to exhibit symmetry are established.Algorithms for finding approximate fits, not constrained to be symmetric,are discussed and some examples are given.

Gender gaps in policy making: Evidence from direct democracy in Switzerland

In spite of increasing representation of women in politics, little is known about their impact onpolicies. Comparing outcomes of parliaments with different shares of female members does not identifytheir causal impact because of possible differences in the underlying electorate. This paper usesa unique data set on voting decisions to sheds new light on gender gaps in policy making. Ouranalysis focuses on Switzerland, where all citizens can directly decide on a broad range of policiesin referendums and initiatives. We show that there are large gender gaps in the areas of health,environmental protection, defense spending and welfare policy which typically persist even conditionalon socio-economic characteristics. We also find that female policy makers have a substantial effect onthe composition of public spending, but a small effect on the overall size of government.

Markups, gaps and the welfare costs of business fluctuations

In this paper we present a simple theory-based measure of the variations in aggregate economic efficiency: the gap between the marginal product of labor and the household s consumption/leisure tradeoff. We show that this indicator corresponds to the inverse of the markup of price over social marginal cost, and give some evidence in support of this interpretation. We then show that, with some auxilliary assumptions our gap variable may be used to measure the efficiency costs of business fluctuations. We find that the latter costs are modest on average. However, to the extent the flexible price equilibrium is distorted,the gross efficiency losses from recessions and gains from booms may be large. Indeed, we find that the major recessions involved large efficiency losses. These results hold for reasonable parameterizations of the Frisch elasticity of labor supply, the coefficient of relative risk aversion, and steady state distortions.

Decomposing Cross-Country Gaps in Obesity and Overweight: Does the Social Environment Matter?

[cat] Una qüestió clau sobre la producció de salut relativament poc explorada es refereix a la influència dels factors socioeconòmics i mediambientals sobre el pes i l’obesitat. Aquesta problemàtica adquireix particular rellevància quan es comparen dos països Mediterranis com Itàlia i Espanya. És interessant adonar-se que l’obesitat a Espanya és 5 punts percentual més elevada al 2003 mentre que a l’any 1990 era aproximadament la mateixa en ambdós països. Aquesta article presenta una descomposició no lineal dels gaps o diferencials en taxes de sobrepès (índex de massa corporal – IMC- entre 25 i 29.9 9 kg/m2), obesitat classe 1 (IMC≥30 kg/m2) i classe 2 (IMC≥35 kg/m2) entre Espanya i Itàlia per gènere i grups d’edat. En explicar aquests gaps entre països aïllem les influències dels estils de vida, els efectes socioeconòmics i els mediambientals. Els nostres resultats indiquen que quan no es controla pels efectes mediambientals (efectes de grup o ‘peer effects’) els hàbits alimentaris i el nivell educatiu són els principals predictors del gaps totals entre països (36-52%), si bé aquests dos factors exerceixen un impacte diferenciat segons gènere i edat. Un tant paradoxalment, quan controlem pels efectes de grup aquests predictors perden la seva capacitat explicativa i els efectes de grup passen a explicar entre el 46-76% dels gaps en sobrepès i obesitat i mostren un patró creixent amb l’edat.