Agglomeration externalities and 1981-2006 regional growth in Brazil

This paper focuses on manufacturing employment growth across the 26 states of Brazil. We employ the Glaeser et al. (1992) approach to identify the role played by knowledge externalities in growth and convergence. To assess robustness of the results, we compare cross-section models, dynamic panel models and pooled-periods fixed-effect models. We find that cross-section models confirm the positive impact of Porter’s and Jacobs’ competition externalities on growth, whereas dynamic panel models and pooled-periods fixed-effect models are consistent with the predictions of Marshall-Arrow-Romer and Porter regarding the role of specialisation in manufacturing vis-à-vis other employment. The results provide new insights into the rapid growth since 1981 in particularly the North and Centre West of Brazil

Agglomeration externalities, innovation and regional growth: Theoretical perspectives and meta-analysis

Technological change and innovation and are central to the quest for regional development. In the globally-connected knowledge-driven economy, the relevance of agglomeration forces that rely on proximity continues to increase, paradoxically despite declining real costs of information, communication and transportation. Globally, the proportion of the population living in cities continues to grow and sprawling cities remain the engines of regional economic transformation. The growth of cities results from a complex chain that starts with scale, density and geography, which then combine with industrial structure characterised by its extent of specialisation, competition and diversity, to yield innovation and productivity growth that encourages employment expansion, and further urban growth through inward migration. This paper revisits the central part of this virtuous circle, namely the Marshall-Arrow-Romer externalities (specialisation), Jacobs externalities (diversity) and Porter externalities (competition) that have provided alternative explanations for innovation and urban growth. The paper evaluates the statistical robustness of evidence for such externalities presented in 31 scientific articles, all building on the seminal work of Glaeser et al. (1992). We aim to explain variation in estimation results using study characteristics by means of ordered probit analysis. Among the results, we find that the impact of diversity depends on how it is measured and that diversity is important for the high-tech sector. High population density increases the chance of finding positive effects of specialisation on growth. More recent data find more positive results for both specialization and diversity, suggesting that agglomeration externalities become more important over time. Finally, primary study results depend on whether or not the externalities are considered jointly and on other features of the regression model specification

A century of the evolution of the urban system in Brazil

In this paper, we study the hitherto unexplored evolution of the size distribution of 185 urban areas in Brazil between 1907 and 2008. We find that the power law parameter of the size distribution of the 100 largest urban areas increases from 0.63 in 1907 to 0.89 in 2008, which confirms an agglomeration process in which the size distribution has become more unequal. A panel fixed effects model pooling the same range of urban size distributions provides a power law parameter equal to 0.53, smaller than those from cross-sectional estimation. Clearly, Zipf’s Law is rejected. The lognormal distribution fits the city size distribution quite well until the 1940s, but since then applies to small and medium size cities only. These results are consistent with our understanding of historical-political and socio-economic processes that have shaped the development of Brazilian cities

Nanomechanical properties of few-layer graphene membranes

We have measured the mechanical properties of few-layer graphene and graphite flakes that are suspended over circular holes. The spatial profile of the flake's spring constant is measured with an atomic force microscope. The bending rigidity of and the tension in the membranes are extracted by fitting a continuum model to the data. For flakes down to eight graphene layers, both parameters show a strong thickness-dependence. We predict fundamental resonance frequencies of these nanodrums in the GHz range based on the measured bending rigidity and tension.Comment: 9 pages, 3 figures, This article has been accepted by Appl. Phys. Lett. After it is published, it will be found at http://apl.aip.org

Societal Change and the Economics of Fertility and Female Labour Force Participation

This paper reports the results of a New Zealand study of one aspect of household economics: the relationship between fertility behaviour and labour supply. Empirical research has shown that the presence of young children affects labour supply of the mother. New Zealand examples are Hyman (1979) and Harris and Raney (1991). However, Hockey and Khawaja (1984) found that a woman's labour force participation negatively affects fertility. In this paper we argue that fertility and labour force participation decisions are determined jointly rather than that there is a one-way causal relationship. We test this hypothesis by means of a simple regression model of fertility and female labour force participation using grouped data from 22 Local Government Regions (LGRs), pooled for the years 1976, 1981 and 1986. The next section discusses some of the theoretical issues. This is followed by a description of the data and a discussion of regression equations. After summing up the results, the last section provides some suggestions for further research