The role of research in viral disease eradication and elimination programs: Lessons for malaria eradication

By examining the role research has played in eradication or regional elimination initiatives for three viral diseases-smallpox, poliomyelitis, and measles-we derive nine cross-cutting lessons applicable to malaria eradication. In these initiatives, some types of research commenced as the programs began and proceeded in parallel. Basic laboratory, clinical, and field research all contributed notably to progress made in the viral programs. For each program, vaccine was the lynchpin intervention, but as the programs progressed, research was required to improve vaccine formulations, delivery methods, and immunization schedules. Surveillance was fundamental to all three programs, whilst polio eradication also required improved diagnostic methods to identify asymptomatic infections. Molecular characterization of pathogen isolates strengthened surveillance and allowed insights into the geographic source of infections and their spread. Anthropologic, sociologic, and behavioural research were needed to address cultural and religious beliefs to expand community acceptance. The last phases of elimination and eradication became increasingly difficult, as a nil incidence was approached. Any eradication initiative for malaria must incorporate flexible research agendas that can adapt to changing epidemiologic contingencies and allow planning for posteradication scenarios. © 2011 Breman et al

Determinants of City Growth in Brazil

In this paper, we examine the determinants of Brazilian city growth between 1970 and 2000. We consider a model of a city, which combines aspects of standard urban economics and the new economic geography literatures. For the empirical analysis, we constructed a dataset of 123 Brazilian agglomerations, and estimate aspects of the demand and supply side as well as a reduced form specification that describes city sizes and their growth. Our main findings are that increases in rural population supply, improvements in inter-regional transport connectivity and education attainment of the labor force have strong impacts on city growth. We also find that local crime and violence, measured by homicide rates impinge on growth. In contrast, a higher share of private sector industrial capital in the local economy stimulates growth. Using the residuals from the growth estimation, we also find that cities who better administer local land use and zoning laws have higher growth. Finally, our policy simulations show that diverting transport investments from large cities towards secondary cities do not provide significant gains in terms of national urban performance.

Determinants of city growth in Brazil

The authors examine the determinants of Brazilian city growth between 1970 and 2000. They consider a model of a city that combines aspects of standard urban economics and the new economic geography literatures. For the empirical analysis, the authors construct a dataset of 123 Brazilian agglomerations and estimate aspects of the demand and supply side, as well as a reduced form specification that describes city sizes and their growth. Their main findings are that increases in rural population supply, improvements in interregional transport connectivity, and education attainment of the labor force have strong impacts on city growth. They also find that local crime and violence, measured by homicide rates, impinge on growth. In contrast, a higher share of private sector industrial capital in the local economy stimulates growth. Using the residuals from the growth estimation, the authors also find that cities that better administer local land use and zoning laws have higher growth. Finally, their policy simulations show that diverting transport investments from large cities toward secondary cities does not provide significant gains in terms of national urban performance.Economic Theory&Research,City Development Strategies,Municipal Financial Management,Achieving Shared Growth,Economic Growth

Examining the growth patterns of Brazilian cities

The share of urban population in Brazil increased from 58 to 80 percent between 1970 and 2000 and all net population growth over the next 30 years is predicted to be in cities. This paper explores population growth and its implications for economic dynamics and income generation among 123 urban agglomerations. Incomes are higher in larger agglomerations and in the South, but there is some indication of regional convergence with higher rates of income growth in poorer areas. In particular, agglomerations in the North and Central-West are growing faster than the more established urban centers in the South. Economic dynamics point to a process of increased diversification among larger cities, and greater specialization among medium-sized agglomerations. In bigger centers there is a trend toward deconcentration toward the periphery. The paper provides a simple analysis of correlates of labor supply, as measured by population growth and economic productivity, which is proxied by changes in per capita income.

Sistemas agroflorestais e mudanças na qualidade do solo em assentamento de reforma agrária.

Os sistemas agroflorestais (SAFs) vêm sendo uma alternativa de produção agrícola que alia a produção de alimentos com a recuperação e conservação dos recursos naturais no assentamento Sepé- Tiarajú, localizado na região canavieira de Ribeirão Preto e primeiro assentamento na modalidade Projeto de Desenvolvimento Sustentável no Estado de São Paulo. Este trabalho objetivou avaliar os efeitos dos SAFs na qualidade do solo do assentamento, através de 10 indicadores qualitativos da qualidade do solo, comparando-se os relatos de 10 agricultores sobre o momento anterior ao uso dos SAFs com o momento atual. Os resultados mostram que os SAFs contribuíram para a descompactação do solo, controle de erosão, aumento de retenção de umidade, escurecimento do solo, aumento da ocorrência de plantas indicadoras de solos de boa qualidade, melhoria no crescimento, desenvolvimento, aspecto e produção dos cultivos, aumento da ocorrência de minhocas, insetos e outros organismos no solo e diminuição do ataque de pragas e doenças

Resonant helical deformations in nonhomogeneous Kirchhoff filaments

We study the three-dimensional static configurations of nonhomogeneous Kirchhoff filaments with periodically varying Young's modulus. This type of variation may occur in long tandemly repeated sequences of DNA. We analyse the effects of the Young's modulus frequence and amplitude of oscillation in the stroboscopic maps, and in the regular (non chaotic) spatial configurations of the filaments. Our analysis shows that the tridimensional conformations of long filaments may depend critically on the Young's modulus frequence in case of resonance with other natural frequencies of the filament. As expected, far from resonance the shape of the solutions remain very close to that of the homogeneous case. In the case of biomolecules, it is well known that various other elements, besides sequence-dependent effects, combine to determine their conformation, like self-contact, salt concentration, thermal fluctuations, anisotropy and interaction with proteins. Our results show that sequence-dependent effects alone may have a significant influence on the shape of these molecules, including DNA. This could, therefore, be a possible mechanical function of the ``junk'' sequences.Comment: 18 pages (twocolumn), 5 figures Revised manuscrip

Utilização de práticas agroecológicas na construção de projetos sustentáveis para a reforma agrária: um estudo de caso no assentamento Sepé Tiaraju – SP.

O assentamento Sepé Tiaraju, situado na região canavieira de Ribeirão Preto (SP), constitui-se o primeiro na modalidade PDS (Projeto de Desenvolvimento Sustentável) no Estado de São Paulo e tem a agroecologia como centro da matriz tecnológica. Dentro desta proposta, o uso de Sistemas Agroflorestais (SAFs) vem constituindo-se como uma alternativa de estímulo econômico à recuperação florestal e incorporação do componente arbóreo nos sistemas produtivos dos agricultores. Este trabalho visa levantar experiências de SAFs executadas pelos assentados em seus lotes e de como as práticas agroecológicas desenvolvidas pelos mesmos vêm contribuindo para a construção de um novo modelo de assentamento. A pesquisa, realizada por intermédio de técnicas de diagnóstico rural participativo, abrangeu um conjunto de 32 famílias. Observou-se que com a elevação da diversificação dos cultivos nos SAFs os assentados aumentaram a estabilidade de seus agroecossistemas, resultando na menor dependência de insumos externos. Também constatou-se que estágios mais avançados da transição agroecológica estão sendo alcançados por assentados que fazem uso de SAFs

A geometric network model of intrinsic grey-matter connectivity of the human brain

Network science provides a general framework for analysing the large-scale brain networks that naturally arise from modern neuroimaging studies, and a key goal in theoretical neuro- science is to understand the extent to which these neural architectures influence the dynamical processes they sustain. To date, brain network modelling has largely been conducted at the macroscale level (i.e. white-matter tracts), despite growing evidence of the role that local grey matter architecture plays in a variety of brain disorders. Here, we present a new model of intrinsic grey matter connectivity of the human connectome. Importantly, the new model incorporates detailed information on cortical geometry to construct ‘shortcuts’ through the thickness of the cortex, thus enabling spatially distant brain regions, as measured along the cortical surface, to communicate. Our study indicates that structures based on human brain surface information differ significantly, both in terms of their topological network characteristics and activity propagation properties, when compared against a variety of alternative geometries and generative algorithms. In particular, this might help explain histological patterns of grey matter connectivity, highlighting that observed connection distances may have arisen to maximise information processing ability, and that such gains are consistent with (and enhanced by) the presence of short-cut connections

The liquid-vapor interface of an ionic fluid

We investigate the liquid-vapor interface of the restricted primitive model (RPM) for an ionic fluid using a density-functional approximation based on correlation functions of the homogeneous fluid as obtained from the mean-spherical approximation (MSA). In the limit of a homogeneous fluid our approach yields the well-known MSA (energy) equation of state. The ionic interfacial density profiles, which for the RPM are identical for both species, have a shape similar to those of simple atomic fluids in that the decay towards the bulk values is more rapid on the vapor side than on the liquid side. This is the opposite asymmetry of the decay to that found in earlier calculations for the RPM based on a square-gradient theory. The width of the interface is, for a wide range of temperatures, approximately four times the second moment correlation length of the liquid phase. We discuss the magnitude and temperature dependence of the surface tension, and argue that for temperatures near the triple point the ratio of the dimensionless surface tension and critical temperature is much smaller for the RPM than for simple atomic fluids.Comment: 6 postscript figures, submitted to Phys. Rev.

Experimental investigation of classical and quantum correlations under decoherence

It is well known that many operations in quantum information processing depend largely on a special kind of quantum correlation, that is, entanglement. However, there are also quantum tasks that display the quantum advantage without entanglement. Distinguishing classical and quantum correlations in quantum systems is therefore of both fundamental and practical importance. In consideration of the unavoidable interaction between correlated systems and the environment, understanding the dynamics of correlations would stimulate great interest. In this study, we investigate the dynamics of different kinds of bipartite correlations in an all-optical experimental setup. The sudden change in behaviour in the decay rates of correlations and their immunity against certain decoherences are shown. Moreover, quantum correlation is observed to be larger than classical correlation, which disproves the early conjecture that classical correlation is always greater than quantum correlation. Our observations may be important for quantum information processing.Comment: 7 pages, 4 figures, to appear in Nature Communication