Credit cycles in theory and experiment

We test in the laboratory the potential of evolutionary dynamics as predictor of actual behavior. To this end, we propose an asymmetricgame -which we interpret as a borrowerlender relation-, study itsevolutionary dynamics in a random matching set-up, and tests itspredictions. The model provides conditions for the existence ofcredit markets and credit cycles. The theoretical predictions seemto be good approximations of the experimental results.

Contracting externalities and multiple equilibria in sectors: Theory and evidence

We consider an economy where the production technology has constantreturns to scale but where in the descentralized equilibrium thereare aggregate increasing returns to scale. The result follows froma positive contracting externality among firms. If a firms issurrounded by more firms, employees have more opportunitiesoutside their own firm. This improves employees' incentives toinvest in the presence of ex post renegotiation at the firm level,at not cost. Our leading result is that if a region is sparselypopulated or if the degree of development in the region is lowenough, there are multiple equilibria in the level of sectorialemployment. From the theoretical model we derive a non-linearfirst-order censored difference equation for sectoral employment.Our results are strongly consistent with the multiple equilibriahypothesis and the existence of a sectoral critical scale (belowwich the sector follows a delocation process). The scale of theregions' population and the degree of development reduce thecritical scale of the sector.

Externalities and interdependent growth: Theory and evidence

I formulate and estimate a model of externalities within countriesand technological interdependence across countries. I find that externalreturns to scale to physical capital within countries are 8 percent; thata 10 percent increase of total factor productivity of a country's neighborsraises its total factor productivity by 6 percent; and that a 2 percentannual growth rate of labor productivity can be explained as an endogenousresponse to an exogenous 0.2 percent annual growth rate of total factorproductivity in the steady--state.

Conflicts of interest, information provision and competition in banking

In some markets, such as the market for drugs or for financial services, sellers have better information than buyersregarding the matching between the buyer's needs and the good's actual characteristics. Depending on the market structure,this may lead to conflicts of interest and/or the underprovision of information by the seller. This paper studies this issuein the market for financial services. The analysis presents a new model of competition between banks, as banks' pricecompetition influences the ensuing incentives for truthful information revelation. We compare two different firm structures,specialized banking, where financial institutions provide a unique financial product, and one-stop banking, where a financialinstitution is able to provide several financial products which are horizontally differentiated. We show first that, althoughconflicts of interest may prevent information disclosure under monopoly, competition forces full information provision forsufficiently high reputation costs. Second, in the presence of market power, one-stop banks will use information strategicallyto increase product differentiation and therefore will always provide reliable information and charge higher rices thanspecialized banks, thus providing a new justification for the creation of one-stop banks. Finally, we show that, ifindependent financial advisers are able to provide reliable information, this increases product differentiation and thereforemarket power, so that it is in the interest of financial intermediaries to promote external independent financial advice.

Social security in theory and practice (I): Facts and political theories

166 countries have some kind of public old age pension. What economic forcescreate and sustain old age Social Security as a public program? We document some of the internationally and historically common features of Social Security programs including explicit and implicit taxes on labor supply, pay-as-you-go features, intergenerational redistribution, benefits which areincreasing functions of lifetime earnings and not means-tested. We partition theories of Social Security into three groups: "political", "efficiency" and "narrative" theories. We explore three political theories in this paper: the majority rational voting model (with its two versions: "the elderly as the leaders of a winning coalition with the poor" and the "once and for all election" model), the "time-intensive model of political competition" and the "taxpayer protection model". Each of the explanations is compared with the international and historical facts. A companion paper explores the "efficiency" and "narrative" theories, and derives implicationsof all the theories for replacing the typical pay-as-you-go system with a forced savings plan.

Endogeneous matching in university-industry collaboration: Theory and empirical evidence from the UK

We develop a two-sided matching model to analyze collaboration between heterogeneousacademics and firms. We predict a positive assortative matching in terms of both scientificability and affinity for type of research, but negative assortative in terms of ability on one sideand affinity in the other. In addition, the most able and most applied academics and the mostable and most basic firms shall collaborate rather than stay independent. Our predictionsreceive strong support from the analysis of the teams of academics and firms that proposeresearch projects to the UK's Engineering and Physical Sciences Research Council.

Inclusive fitness theory and eusociality.

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.

Informe sobre la I International Conference on Multidisciplinary Information Sciences and Technologies - InSciT2006 (Mèrida, 25, 26, 27 i 28 d'octubre de 2006)

Podeu consultar la versió en castellà a http://hdl.handle.net/2445/8955

Informe sobre la I International Conference on Multidisciplinary Information Sciences and Technologies - InSciT2006 (Mérida, 25, 26, 27 y 28 de octubre de 2006)

Podeu consultar la versió en català a http://hdl.handle.net/2445/8954

Quasilocal density functional theory and its application within the extended Thomas-Fermi approximation

In this paper we propose a generalization of the density functional theory. The theory leads to single-particle equations of motion with a quasilocal mean-field operator, which contains a quasiparticle position-dependent effective mass and a spin-orbit potential. The energy density functional is constructed using the extended Thomas-Fermi approximation and the ground-state properties of doubly magic nuclei are considered within the framework of this approach. Calculations were performed using the finite-range Gogny D1S forces and the results are compared with the exact Hartree-Fock calculations

Relaxation times in a bistable system with parametric, white noise: Theory and experiment

We consider the effects of external, multiplicative white noise on the relaxation time of a general representation of a bistable system from the points of view provided by two, quite different, theoretical approaches: the classical Stratonovich decoupling of correlations and the new method due to Jung and Risken. Experimental results, obtained from a bistable electronic circuit, are compared to the theoretical predictions. We show that the phenomenon of critical slowing down appears as a function of the noise parameters, thereby providing a correct characterization of a noise-induced transition.