Formal Education and Public Knowledge

In this paper, I examine the transitional dynamics of an economy populated by individuals who split their time between acquiring a formal education, producing final goods, and innovating. The paper has two objectives: (i) uncovering the macroeconomic circumstances that favored the rise of formal education; (ii) to reconcile the remarkable growth of the education sector with the constancy of other key macroeconomic variables, such as the interest rate, the consumption-output ratio, and the growth rate of per capita income (Kaldor facts). The transitional dynamics of human capital growth models, such as Lucas (1988), would attribute the arrival of education to the diminishing marginal productivity of physical capital. Conversely, the model proposed here suggests that it is the rate of learning that catches up with the rate of return on physical capital. As technical knowledge expands, the rate of return on education increases, and this induces individuals to stay longer in school. The model's transitional paths are matched with long run U.S. educational and economic data.Public Knowledge, Learning Rate, Transitional Dynamics, Calibration.

Human Capital Dispersion and Incentives to Innovate

Do policies that alter the allocation of human capital across individuals affect the innovation capacity of an economy? To answer this question I extend Romer’s growth model to allow for individual heterogeneity. I find that the value of an invention rises with equality. If skills and talents are evenly distributed, inventions are more widely adopted in production and users are willing to bid a higher price. Therefore more inequality is associated with a larger share of the population employed in the business of invention. But, somehow surprisingly, the analysis suggests that although an equal society values inventions more than an unequal one, it may produce fewer of them, or, equivalently, generates inventions of a lower quality. A calibration of the model suggests a weak, but positive, relationship between the rate of innovation and inequality. Finally, in a two-country world, in which ideas, individuals, and capital circulate without restrictions, I find that the unequal economy tends to specialize into the business of innovation. The main implication of the analysis is that an observed difference in the innovation rate between two countries with similar levels of education can hardly be attributed to variations in domestic human capital policies.human capital, inequality, innovation

Human Capital Dispersion and Incentives to Innovate

Do policies that alter the allocation of human capital across individuals affect the innovation capacity of an economy? To answer this question, I extend Romer's (1990) growth model to allow for individual heterogeneity. I find that the value of an invention rises with equality. If skills and talents are evenly distributed, inventions are more widely adopted in production and users are willing to bid a higher price. Therefore, more equality is associated with a larger share of the population employed in the business of invention. However, inventors of an equal society are not as creative as those of an unequal one. As a result an inverted-U curve relating inequality and the innovation rate emerges, indicating that departures from extreme forms of equality or inequality are growth-enhancing. I discuss evidence that agrees with the main implications of the analysis, namely that the market size and the number of inventors are negatively affected by inequality. Finally, a calibration exercise suggests that in recent decades the U.S. has been in the ascending portion of the inequality-growth curve.human capital, inequality, innovation

Dynamic Programming, Maximum Principle and Vintage Capital

We present an application of the Dynamic Programming (DP) and of the Maximum Principle (MP) to solve an optimization over time when the production function is linear in the stock of capital (Ak model). Two views of capital are considered. In one, which is embraced by the great majority of macroeconomic models, capital is homogeneous and depreciates at a constant exogenous rate. In the other view each piece of capital has its own finite productive life cycle (vintage capital). The interpretation of the time patterns of macroaggregates is quite different between the two cases. A technological shock generates an oscillatory movement in the time pattern of per capita output when capital has a vintage structure; conversely an instantaneous adjustment with no transitional dynamics occurs when capital is homogeneous. From a methodological point of view it emerges that the DP approach delivers sharper results than the MP approach (for instance it delivers a closed form solution for the optimal investment strategy) under slacker parameter restrictions. Cross-time and cross-country data on investments, income, and consumption drawn from the Penn World Table version 6.2 are used to evaluate the vintage and standard Ak model.Vintage Capital; Penn World Table; Maximum Principle; Hilbert Space

« Retrouver l’esprit industriel du capitalisme » : de la recherche d’actionnaires patients à celle d’une gouvernance partagée

Le gouvernement, fort de la loi visant à reconquérir l’économie réelle, dite loi Florange, qui institue la possibilité de votes doubles pour les actionnaires patients (conservant leurs actions au moins deux ans), vient de prendre deux décisions significatives en augmentant temporairement sa participation au capital de Renault et d’Air France afin d’éviter qu’en assemblée générale cette possibilité de votes doubles soit rejetée par la majorité qualifiée retenue dans la loi. L’objectif affiché par le Ministre de l’Economie dans une tribune du journal Le Monde est d’aider à « retrouver l’esprit industriel du capitalisme » en privilégiant les engagements à long terme de manière à promouvoir des investissements porteurs d’une croissance solide. Cette initiative conduit à reprendre la discussion sur les conditions de gouvernance des sociétés par actions (‘corporations’) (Pollin, 2004, 2006), à examiner les dérives dont elle a pu être l’objet et les remèdes qui ont pu et pourraient dans l’avenir y être apportés, impliquant de savoir ce que peut en attendre le gouvernement. [Premiers paragraphes

The TP53 colorectal cancer international collaborative study on the prognostic and predictive significance of p53 mutation: influence of tumor site, type of mutation, and adjuvant treatment

PURPOSE: The aims of the TP53 Colorectal Cancer (CRC) International Collaborative Study were to evaluate the possible associations between specific TP53 mutations and tumor site, and to evaluate the prognostic and predictive significance of these mutations in different site, stage, and treatment subgroups. PATIENTS AND METHODS: A total of 3,583 CRC patients from 25 different research groups in 17 countries were recruited to the study. Patients were divided into three groups according to site of the primary tumor. TP53 mutational analyses spanned exons 4 to 8. RESULTS: TP53 mutations were found in 34% of the proximal colon tumors and in 45% of the distal colon and rectal tumors. They were associated with lymphatic invasion in proximal tumors. In distal colon tumors, deletions causing loss of amino acids were associated with worse survival. In proximal colon tumors, mutations in exon 5 showed a trend toward statistical significance (P < .05) when overall survival was considered. Dukes' C tumors with wild-type TP53 and those with mutated TP53 (proximal tumors) showed significantly better prognosis when treated with adjuvant chemotherapy. CONCLUSION: Analysis of TP53 mutations from a large cohort of CRC patients has identified tumor site, type of mutation, and adjuvant treatment as important factors in determining the prognostic significance of this genetic alteration

Reply: Thymidylate synthase polymorphism and survival of colorectal cancer patients treated with 5-fluorouracil

British Journal of Cancer (2002) 86, 1366. DOI: 10.1038/sj/bjc/6600230 www.bjcancer.co

A dynamic analysis of nash equilibria in search models with fiat money

We analyze the rise in the acceptability fiat money in a Kiyotaki–Wright economy by developing a method that can determine dynamic Nash equilibria for a class of search models with genuine heterogeneous agents. We also address open issues regarding the stability properties of pure strategy equilibria and the presence of multiple equilibria, numerical experiments illustrate the liquidity conditions that favor the transition from partial to full acceptance of fiat money, and the effects of inflationary shocks on production, liquidity, and trade

Comparison of the intracellular trafficking itinerary of ctla-4 orthologues.

CTLA-4 is an essential inhibitor of T cell immune responses. At steady state, most CTLA-4 resides in intracellular compartments due to constitutive internalisation mediated via a tyrosine based endocytic motif (YVKM) within the cytoplasmic domain. This domain is highly conserved in mammals suggesting strong selective pressure. In contrast, the C-terminal domain varies considerably in non-mammals such as fish, xenopus and birds. We compared the ability of the C-terminus of these species to direct the trafficking of CTLA-4 with human CTLA-4. Using a chimeric approach, endocytosis was found to be conserved between human, xenopus and chicken CTLA-4 but was reduced substantially in trout CTLA-4, which lacks the conserved YXXM motif. Nevertheless, we identified an alternative YXXF motif in trout CTLA-4 that permitted limited endocytosis. Post-internalisation, CTLA-4 was either recycled or targeted for degradation. Human and chicken CTLA-4, which contain a YVKM motif, showed efficient recycling compared to xenopus CTLA-4 which contains a less efficient YEKM motif. Specific mutation of this motif in human CTLA-4 reduced receptor recycling. These findings suggest evolutionary development in the endocytic and recycling potential of CTLA-4, which may facilitate more refined functions of CTLA-4 within the mammalian immune system