General equilibrium with asymmetric information: a dual approach

We study markets where the characteristics or decisions of certain agents are relevant but not known to their trading partners. Assuming exclusive transactions, the environment is described as a continuum economy with indivisible commodities. We characterize incentive efficient allocations as solutions to linear programming problems and appeal to duality theory to demonstrate the generic existence of external effects in these markets. Because under certain conditions such effects may generate non-convexities, randomization emerges as a theoretic possibility. In characterizing market equilibria we show that, consistently with the personalized nature of transactions, prices are generally non-linear in the underlying consumption. On the other hand, external effects may have critical implications for market efficiency. With adverse selection, in fact, cross-subsidization across agents with different private information may be necessary for optimality, and so, the market need not even achieve an incentive efficient allocation. In contrast, for the case of a single commodity, we find that when informational asymmetries arise after the trading period (e.g. moral hazard; ex post hidden types) external effects are fully internalized at a market equilibrium.

Mediation incomplete information bargaining with filtered communication

We analyze a continuous-time bilateral double auction in the presence of two-sided incomplete information and a smallest money unit. A distinguishing feature of our model is that intermediate concessions are not observable by the adversary: they are only communicated to a passive auctioneer. An alternative interpretation is that of mediated bargaining. We show that an equilibrium using only the extreme agreements always exists and display the necessary and sufficient condition for the existence of (perfect Bayesian) equilibra which yield intermediate agreements. For the symmetric case with uniform type distribution we numerically calculate the equilibria. We find that the equilibrium which does not use compromise agreements is the least efficient, however, the rest of the equilibria yield the lower social welfare the higher number of compromise agreements are used.

Allocative and productive efficiency in REE with asymetric information

We characterize the divergence between informational and economic efficiency in a rational expectations competitive market with asymmetric information about the costs of production. We find that prices may contain too much or too little information with respect to incentive efficient allocations depending on whether the main role of the price is, respectively, the traditional as index of scarcity or informational. Only when REE degenerate to Cournot equilibria the market solution does not show llocative inefficiency. With multidimensional uncertainty we find that the REE price does not have in general the incentive efficient information mix: It pays to sacrifice allocative efficiency at the REE to improve productive efficiency.

Information networks and worker recruitment

This paper studies experimentally how the existence of social information networks affects the ways in which firms recruit new personnel. Through such networks firms learn about prospective employees' performance in previous jobs. Assuming individualistic preferences social networks are predicted not to affect overall labor market behavior, while with social preferences the prediction is that when bilaterally negotiated: (i) wages will be higher and (ii) that workers in jobs with incomplete contracts will respond with higher effort. Our experimental results are consistent with the social preferences view, both for the case of excess demand and excess supply of labor. In particular, the presence of information networks leads to more efficient allocations.

Bioequivalence of meat products treated with high pressure processing

The effects of high pressure on the composition of food products have not been evaluated extensively. Since, it is necessary to take in consideration the possible effects in basis to the changes induced in the bio molecules by the application of high pressures. The main effect on protein is the denaturation, because the covalent bonds are not affected; however hydrogen bonding, hydrophobic and intermolecular interactions are modified or destroyed. 1 High pressure can modify the activity of some enzymes. If this is done the proteolysis and lipolysis could be more or less intense and the content of free amino acids and fatty acids will be different. This could be related to the bioavailability of these compounds. Low pressures (100 MPa) have been shown to activate some enzymes (monomeric enzymes). Higher pressures induce loss of the enzyme activity. However some enzymes are very stable (ex. Lipase ~ 600 - 1000 MPa). Lipoxygenase is less stable, and there is little information about the effects on antioxidant enzymes. Other important issue is the influence of high pressure on oxidation susceptibility. This could modify the composition of lipids if the degree of the oxidation would have been higher or lower than in the traditional product. Pressure produces the damage of cell membranes favouring the contact between substrates and enzymes, exposure to oxidation of membrane fatty acids and loos of the efficiency of vitamin E. These effects can also affect to protein oxidation. In this study different compounds were analysed to establish the differences between non-treated and high-pressure treated products.

Documentation and sport information: the challenges and opportunities brought by new technologies

This text corresponds to the contents of the seminar “Information Services at the Sport Institutions” held by the author as part of the programme of activities of the Invited Professor of Olympism of the International Chair in Olympism (IOC-UAB) in 2001. The seminar discusses the potential of technologies such as the Internet in sports documentation.

The Olympic Movement and Information Society: New Internet Challenges and Opportunities

Article describing the current situation of the Internet, the use of Internet by sport institutions, and the relationship between the Internet and the Olympic Games, and the Olympic Movement. This paper was presented at the International Symposium on Television in the Olympic Games held in Lausanne in October 1998.

Multi-product firms and product variety

The goal of this paper is to study the role of multi-product firms in the market provision of product variety. The analysis is conducted using the spokes model of non-localized competition proposed by Chen and Riordan (2007). Firstly, we show that multi-product firms are at a competitive disadvantage vis-a-vis single-product firms and can only emerge if economies of scope are sufficiently strong. Secondly, under duopoly product variety may be higher or lower with respect to both the first best and the monopolistically competitive equilibrium. However, within a relevant range of parameter values duopolists drastically restrict their product range in order to relax price competition, and as a result product variety is far below the efficient level.

Un diàleg de sords: intentant donar sentit al debat sobre la publicació electrònica

Aquest article se centra en les implicacions de la difusió electrònica per al sistema de publicació de revistes basat en la revisió per parells [peer-reviewed]. Per donar sentit a un assumpte tan complex, és de molt ajut mirar-s'ho des de la perspectiva dels orígens del sistema i de les seves tres funcions nuclears: el rànquing en la recerca, facilitar la comunicació interactiva entre els estudiosos i crear un arxiu global del coneixement científic. Cadascuna d’aquestes funcions principals té requeriments diferents que, en certa mesura, se sobreposen però que també entren, d'alguna manera, en conflicte. Internet obre la possibilitat de desenvolupar una varietat de models distints de comunicació científica modulant la intensitat de cadascun d'aquests tres rols que les revistes en paper han desenvolupat i, possiblement, d'altres funcions que no eren ni tan sols imaginables abans del desenvolupament de les xarxes electròniques d'abast planetari. Les implicacions de la distribució electrònica per a la propietat i accés a la literatura científica són profundes i tendeixen a agreujar la ja seriosa crisi dels preus de les revistes que està frenant l'accés a la informació científica. La comunitat d'estudiosos, que és autora del material que aquestes publicacions contenen i, al mateix temps, n'és el principal consumidor, està en possessió de la clau per a solucionar aquesta crisi tot permetent a Internet ser un vehicle que faciliti la difusió d’una recerca finançada des del sector públic en comptes de crear una situació de propietat privada d'aquesta recerca.

Diseño e implementación de un sistema PDM

En aquest projecte s'ha realitzat el disseny i la implementació d'un sistema PDM genèric mitjançant el qual sigui posible crear i gestionar la informació relacionada amb un producte. Amb aquesta eina web realitzada fent ús del patró d'arquitectura MVC, es pretèn disminuir la pèrdua de temps i de dades a la organització de dades de disseny, millorar la productivitat i augmentar la col·laboració.

Co-movements between US and UK stock prices: the roles of macroeconomic information and time-series varying conditional correlations

This paper provides evidence on the sources of co-movement in monthly US and UK stock price movements by investigating the role of macroeconomic and financial variables in a bivariate system with time-varying conditional correlations. Crosscountry communality in response is uncovered, with changes in the US Federal Funds rate, UK bond yields and oil prices having similar negative effects in both markets. Other variables also play a role, especially for the UK market. These effects do not, however, explain the marked increase in cross-market correlations observed from around 2000, which we attribute to time variation in the correlations of shocks to these markets. A regime-switching smooth transition model captures this time variation well and shows the correlations increase dramatically around 1999-2000. JEL classifications: C32, C51, G15 Keywords: international stock returns, DCC-GARCH model, smooth transition conditional correlation GARCH model, model evaluation.

The Complete Information First. Price Auction or the Importance of Being Indivisible

Abstract Despite the popularity of auction theoretical thinking, it appears that no one has presented an elementary equilibrium analysis of the first-price sealed-bid auction mechanism under complete information. This paper aims to remedy that omission. We show that the existence of pure strategy undominated Nash equilibria requires that the bidding space is not "too divisible" (that is, a continuum). In fact, when bids must form part of a finite grid there always exists a "high price equilibrium". However, there might also be "low price equilibria" and when the bidding space is very restrictive the revenue obtained in these "low price equilibria" might be very low. We discuss the properties of the equilibria and an application of auction theoretical thinking in which "low price equilibria" may be relevant. Keywords: First-price auctions, undominated Nash equilibria. JEL Classification Numbers: C72 (Noncooperative Games), D44 (Auctions).

Pautes de privacitat pels proveïdors de recursos electrònics

Les biblioteques llicencien la informació electrònica en nom dels seus clients i administradors. L'accés a la majoria dels recursos electrònics disponibles a les biblioteques es proporciona a través del world wide web per mitjà de les interfícies dels navegadors. La ràpida evolució del world wide web, com el mecanisme més gran de distribució d'informació, ha fet del web una rica font d'informació per als proveïdors sobre els interessos, comportaments i hàbits dels usuaris. De vegades es dóna el cas de que aquest tipus d'informació és recollida durant la utilització d'un producte web sense el coneixement o permís de l'individu que està utilitzant el producte.

Government information transparency

This paper studies a model of announcements by a privately informed government about the future state of the economic activity in an economy subject to recurrent shocks and with distortions due to income taxation. Although transparent communication would ex ante be desirable, we find that even a benevolent government may ex-post be non-informative, in an attempt to countervail the tax distortion with a "second best" compensating distortion in information. This result provides a rationale for independent national statistical offices, committed to truthful communication. We also find that whether inequality in income distribution favors or harms government transparency depends on labor supply elasticity.

Testing low-altitude infrared digital photography from a mini-UAV to retrieve information for biological conservation

Satellite remote sensing imagery is used for forestry, conservation and environmental applications, but insufficient spatial resolution, and, in particular, unavailability of images at the precise timing required for a given application, often prevent achieving a fully operational stage. Airborne remote sensing has the advantage of custom-tuned sensors, resolution and timing, but its price prevents using it as a routine technique for the mentioned fields. Some Unmanned Aerial Vehicles might provide a “third way” solution as low-cost techniques for acquiring remotely sensed information, under close control of the end-user, albeit at the expense of lower quality instrumentation and instability. This report evaluates a light remote sensing system based on a remotely-controlled mini-UAV (ATMOS-3) equipped with a color infra-red camera (VEGCAM-1) designed and operated by CATUAV. We conducted a testing mission over a Mediterranean landscape dominated by an evergreen woodland of Aleppo pine (Pinus halepensis) and (Holm) oak (Quercus ilex) in the Montseny National Park (Catalonia, NE Spain). We took advantage of state-of-the-art ortho-rectified digital aerial imagery (acquired by the Institut Cartogràfic de Catalunya over the area during the previous year) and used it as quality reference. In particular, we paid attention to: 1) Operationality of flight and image acquisition according to a previously defined plan; 2) Radiometric and geometric quality of the images; and 3) Operational use of the images in the context of applications. We conclude that the system has achieved an operational stage regarding flight activities, although with meteorological limits set by wind speed and turbulence. Appropriate landing areas can be sometimes limiting also, but the system is able to land on small and relatively rough terrains such as patches of grassland or short matorral, and we have operated the UAV as far as 7 km from the control unit. Radiometric quality is sufficient for interactive analysis, but probably insufficient for automated processing. A forthcoming camera is supposed to greatly improve radiometric quality and consistency. Conventional GPS positioning through time synchronization provides coarse orientation of the images, with no roll information.