Learning from Private and Public Observation of Other's Actions

We study how a continuum of agents learn about disseminated information by observing others’ actions. Every period each agent observes a public and private noisy signal centered around the aggregate action taken by the population. The public signal represents an endogenous aggregate variable such as a price or a quantity. The private signal represents the information gathered through private communication and local interactions. We identify conditions such that the average learning curve is S-shaped: learning is slow initially, intensifies rapidly, and finally converges slowly to the truth. We show that increasing public information always slows down learning in the long run and, under some conditions, reduces welfare. Lastly, optimal diffusion of information requires that agents “strive to be different”: agents need to be rewarded for choosing actions away from the population average.Learning externality; welfare cost of public information

Investment Cycles and Sovereign Debt Overhang

We characterize optimal taxation of foreign capital and optimal sovereign debt policy in a small open economy where the government cannot commit to policy and seeks to insure a risk averse domestic constituency. The expected tax on capital is shown to vary with the state of the economy, generating cyclicality in investment and debt in an environment where the first best capital stock is a constant. The government's lack of commitment induces a negative correlation between investment and the stock of government debt, a "debt overhang'' effect. If the government discounts the future at a rate higher than the market, then capital oscillates indefinitely at a level strictly below the first best. Debt relief is never Pareto improving and cannot affect the long-run level of investment. Further, restricting the government to a balanced budget can eliminate the cyclical distortion of investment.

Efficient Fiscal Policy and Amplification

We provide a rationale for the observed pro-cyclicality of tax policies in emerging markets and present a novel mechanism through which tax policy amplifies the business cycle. Our explanation relies on two features of emerging markets: limited access to financial markets and limited commitment to tax policy. We present a small open economy model with capital where a government maximizes the utility of a working population that has no access to financial markets and is subject to endowment shocks. The government's insurance motive generates pro-cyclical taxes on capital income. If the government could commit, this policy is not distortionary. However, we show that if the government lacks the ability to commit, the best fiscal policy available exacerbates the economic cycle by distorting investment during recessions. We characterize the mechanism through which limited commitment generates cycles in investment in an environment where under commitment investment would be constant. We extend our results to standard productivity shocks and to the case where the government has access to intra-period insurance markets. Lastly, we conjecture that our results would hold as well if the government could issue debt subject to borrowing constraints.

Commitment Vs. Flexibility

This paper studies the optimal trade-off between commitment and flexibility in an intertemporal consumption/savings choice model. Individuals expect to receive relevant information regarding their own situation and tastes - generating a value for flexibility - but also expect to suffer from temptations - generating a value for commitment. The model combines the representations of preferences for flexibility introduced by Kreps (1979) with its recent antithesis for commitment proposed by Gul and Pesendorfer (2002), which nests the hyperbolic discounting model. We set up and solve a mechanism design problem that optimizes over the set of consumption/saving options available to the individual each period. We characterize the conditions under which the solution takes a simple threshold form where minimum savings policies are optimal. Our analysis is also relevant for other issues such as situations with externalities or the problem faced by a 'paternalistic' planner, which may be important for thinking about some regulations such as forced minimum schooling laws.

Gas mass-flow meters: Principles and applications

Gas mass-flow meters (GMFM) for original equipment manufacturers (OEM) applications are presently found in a relatively easy and cheap way. GMFM may be applied in a number of different situations but technical formation concerning its principles of measurement and applications are still misleading. In this paper, the principles of GMFM measurement are discussed and the operating parameters are clarified. A concept of gas mass-flow response factor is introduced and further used in a model for gas mass-flow measurement that is suitable to any gas mixture of known composition. In addition, a model for the application of GMFM to dynamic volumetric methods of dilution is presented and generalized

Flexor tendon injuries in children. About a series of cases

Introduction: Flexor tendon injuries in children represent a diagnostic and therapeutic challenge for the surgeons involved in the treatment. These Injuries go unnoticed, directed rehabilitation is difficult but good results are achieved during follow-up. The objective of this study is to describe the clinical characteristics of a series of pediatric patients with injuries of flexor tendons of the hand and their functional results. Materials and methods: This is a retrospective study of patients with flexor tendon injuries over a two-year period. Variables analyzed were: age, sex, laterality, trauma mechanism, affected area, associated lesions and results with TAM scale. Inclusion criteria: age 0-16 years, diagnosis of flexor lesion and minimum follow-up of 10 weeks. Results: Twenty-one patients were found, 15 of them had a cutting injury. One case had bilateral involvement. Zone V was the most affected in all cases, followed by zone II. The most frequent associated lesions were colateral nerve and ulnar nerve injuries. Short-term results were good in most patients. Conclusions: A high index of suspicion is necessary for the diagnosis of these lesions; In pediatric patients, surgical exploration is recommended in case of clinical suspicion of tendinous lesion. Primary repair is the gold standard of treatment and the results are good with an adequate follow-up and immobilization protocol

Propriedades Termofísicas de alguns Gases, Sólidos e da Água

Trata-se de um trabalho que resultou da compilação de informação com o objectivo de fornecer informação de base aos modelos computacionais que temos em uso para diversas finalidades (docência, investigação e desenvolvimento)

Dressing Spain? Costume and National Identity in the Reign of Charles III

Se pretende analizar el discurso identitario subyacente en dos obras impresas durante el reinado de Carlos III: el libro Discurso sobre el luxô de las señoras (1788) y el repertorio de grabados Colección de trages de España (1777-1790) de Juan de la Cruz Cano.This article aims to examine the identity discourse which underlies in two printed works published during the reign of Charles III: the book Discurso sobre el luxô de las señoras (1788) and the collection of engravings Colección de trages de España (1777-1790) by Juan de la Cruz Cano