Public Inputs and Endogenous Growth in the Agricultural Sector: a Dynamic Dual Approach

This paper examines growth in the U.S. agricultural sector under the conditions hypothesized by endogenous growth theory. Public capital and R&D are explicitly considered to capture the effects of public inputs in a model based on dynamic duality theory. Results support some necessary conditions for this hypothesis to be true.International Development,

PUBLIC CAPITAL, R&D, AGRICULTURAL PRODUCTION AND ENDOGENOUS GROWTH

The paper examines growth in the U.S. agricultural sector under the conditions hypothesized by endogenous growth theory. Public capital and R&D in agriculture are explicitly considered to capture the effect of public inputs. Results support some of the necessary conditions for this hypothesis to be true.Agricultural and Food Policy, Public Economics,

Public Inputs and Productivty in the Agricultural Sector: A Dynamic Dual Approach

This paper introduces a dynamic model of productivity measurement based on recent endogenous growth theories. The model presented in this study is based on dynamic duality theory and incorporate public goods (public capital and R&D) as external factors to the firms. It also rationalizes the provision of public inputs by a benevolent social planner that internalizes the effects of them. Moreover, the Le Chatelier principle is extended for this dynamic duality modelin which the public factors are quasi-fixed for the firm and all firm-specific inputs can be adjusted in the long run. Therefore, increasing returns to scale over all inputs can still be tested at the long-run equilibrium perceived by the firm. Additionally, this model permits deriving testable hypotheses related to the two conditions of endogenous growth theory mentioned above. The model is tested with data for the U.S. agricultural sector.endogenous growth, dynamic productivity, public goods, duality, U.S. agriculture

Public inputs and dynamic producer behavior: endogenous growth in U.S. agriculture

This paper is an attempt to understand the impact of public RD (2) positive effect of additional units of public inputs on the long-run demand for private capital; and (3) negative impact of public inputs on cost. They are tested using two estimation procedures on two data sets for U.S. agriculture. One, covering the period 1948–1994, developed by USDA, the other, covering the period 1926–1990, from Thirtle et al. Maximum likelihood estimates do not conform to the regularity and behavioral properties of the economic model rendering them unusable for testing these hypotheses. Bayesian estimates, although not totally satisfactory, do not reject the hypotheses after prior imposition of some of the regularity conditions. This supports the notion of an important role for public inputs on the rapid and sustained growth of the sector. We calculate that, on average, one additional dollar spent on public R&D stock reduces private cost by $6.5, implying a return on these public expenses of 190%.Facultad de Ciencias Económica

Uniparental markers of contemporary Italian population reveals details on its pre-Roman heritage.

BACKGROUND: According to archaeological records and historical documentation, Italy has been a melting point for populations of different geographical and ethnic matrices. Although Italy has been a favorite subject for numerous population genetic studies, genetic patterns have never been analyzed comprehensively, including uniparental and autosomal markers throughout the country. METHODS/PRINCIPAL FINDINGS: A total of 583 individuals were sampled from across the Italian Peninsula, from ten distant (if homogeneous by language) ethnic communities--and from two linguistic isolates (Ladins, Grecani Salentini). All samples were first typed for the mitochondrial DNA (mtDNA) control region and selected coding region SNPs (mtSNPs). This data was pooled for analysis with 3,778 mtDNA control-region profiles collected from the literature. Secondly, a set of Y-chromosome SNPs and STRs were also analyzed in 479 individuals together with a panel of autosomal ancestry informative markers (AIMs) from 441 samples. The resulting genetic record reveals clines of genetic frequencies laid according to the latitude slant along continental Italy--probably generated by demographical events dating back to the Neolithic. The Ladins showed distinctive, if more recent structure. The Neolithic contribution was estimated for the Y-chromosome as 14.5% and for mtDNA as 10.5%. Y-chromosome data showed larger differentiation between North, Center and South than mtDNA. AIMs detected a minor sub-Saharan component; this is however higher than for other European non-Mediterranean populations. The same signal of sub-Saharan heritage was also evident in uniparental markers. CONCLUSIONS/SIGNIFICANCE: Italy shows patterns of molecular variation mirroring other European countries, although some heterogeneity exists based on different analysis and molecular markers. From North to South, Italy shows clinal patterns that were most likely modulated during Neolithic times

Public Inputs and dynamic producer behavior: endogenous growth in U.S. agriculture

This paper is an attempt to understand the impact of public R&D and public infrastructure on the performance of the U.S. agricultural sector during the last part of the twentieth century. A neoclassical Solow growth model is not sufficient for this understanding given the sustained growth performance of the sector. We base our analysis on a well known endogenous growth model, the \u27AK model\u27 where nonconvexities are introduced through non-rival inputs. Based on these models and within the dynamic models that rationalize private and public decision making, we have identified three testable hypotheses regarding the aggregate agricultural production technology. They are: 1) increasing returns to scale over all inputs; 2) positive effect of additional units of public inputs on the long-run demand for private capital; and 3) negative impact of public inputs on cost. They are tested using two estimation procedures on two data sets for U.S. agriculture. One, covering the period 1948-1994, developed by USDA, the other, covering the period 1926-1990, from Thirtle et al. Maximum likelihood estimates do not conform to the regularity and behavioral properties of the economic model rendering them unusable for testing these hypotheses. Bayesian estimates, although not totally satisfactory, do not reject the hypotheses after prior imposition of some of the regularity conditions. This supports the notion of an important role for public inputs on the rapid and sustained growth of the sector. We calculate that, on average, one additional dollar spent on public R&D stock reduces private cost by $6.5, implying a return on these public expenses of 190 percent

Public Inputs and Dynamic Producer Behavior: Endogenous Growth in U.S. Agriculture

This paper is an attempt to understand the impact of public R&D and public infrastructure on the performance of the U.S. agricultural sector during the last part of the twentieth century. A neoclassical Solow growth model is not sufficient for this understanding given the sustained growth performance of the sector. We base our analysis on a well known endogenous growth model, the \u27AK model\u27 where nonconvexities are introduced through non-rival inputs. Based on these models and within the dynamic models that rationalize private and public decision making, we have identified three testable hypotheses regarding the aggregate agricultural production technology. They are: 1) increasing returns to scale over all inputs; 2) positive effect of additional units of public inputs on the long-run demand for private capital; and 3) negative impact of public inputs on cost. They are tested using two estimation procedures on two data sets for U.S. agriculture. One, covering the period 1948-1994, developed by USDA, the other, covering the period 1926-1990, from Thirtle et al. Maximum likelihood estimates do not conform to the regularity and behavioral properties of the model rendering them unusable for testing these hypotheses. Bayesian estimates, although not totally satisfactory, do not reject the hypotheses after prior imposition of some of the regularity conditions. This supports the notion of an important role for public inputs on the rapid and sustained growth of the sector. We calculate that, on average, one additional dollar spent on public R&D stock reduces private cost by $6.5, implying a return on these public expenses of 190 percent