Interaction of vortices in viscous planar flows

We consider the inviscid limit for the two-dimensional incompressible Navier-Stokes equation in the particular case where the initial flow is a finite collection of point vortices. We suppose that the initial positions and the circulations of the vortices do not depend on the viscosity parameter \nu, and we choose a time T > 0 such that the Helmholtz-Kirchhoff point vortex system is well-posed on the interval [0,T]. Under these assumptions, we prove that the solution of the Navier-Stokes equation converges, as \nu -> 0, to a superposition of Lamb-Oseen vortices whose centers evolve according to a viscous regularization of the point vortex system. Convergence holds uniformly in time, in a strong topology which allows to give an accurate description of the asymptotic profile of each individual vortex. In particular, we compute to leading order the deformations of the vortices due to mutual interactions. This allows to estimate the self-interactions, which play an important role in the convergence proof.Comment: 39 pages, 1 figur

Prevalence and determinants of chronic respiratory diseases in adults in rural Sudan

BACKGROUND: Chronic respiratory diseases (CRDs) greatly contribute to worldwide mortality. Despite new data emerging from Africa, prevalence estimates and determinants of CRDs in rural settings are limited. This study sought to extend the existing research conducted in urban Sudan by conducting a rural comparison. METHODS: Participants aged ≥18 years (n = 1,850), living in rural Gezira State completed pre-and post-bronchodilator spirometry and a questionnaire. Prevalence of respiratory symptoms and spirometric abnormalities were reported. Regression analyses were used to identify risk factors for CRDs. RESULTS: Prevalence of chronic airflow obstruction (CAO) was 4.1% overall and 5.5% in those aged ≥40 years. Reversibility was seen in 6.4%. Low forced vital capacity (FVC) was seen in 58.5%, and at least one respiratory symptom was present in 40.7% of the participants. CAO was more common among people aged 60-69 years (OR 2.07, 95% CI 1.13-3.82) and less common among highly educated participants (OR 0.50, 95% CI 0.27-0.93). Being underweight was associated with lower FVC (OR 3.07, 95% CI 2.24-4.20). CONCLUSIONS: A substantial burden of CRD exists among adults in rural Sudan. Investment in CRD prevention and management strategies is needed

Institucionalização e execução das políticas públicas de economia solidária no Brasil

O artigo investiga a política pública de economia solidária no governo federal, implementada a partir de 2003 com a criação da Secretaria Nacional de Economia Solidária (SENAES), visando analisar com que mecanismos a temática se converte em política pública no âmbito do governo federal. Partindo do modelo teórico de Kingdon (1995), o artigo analisa, em primeiro lugar, o processo político (em sentido lato) que sucedeu sua inserção como política pública para a geração de trabalho e renda. A seguir, analisa-se os projetos e ações desenvolvidas no programa entre 2003 e 2010, com ênfase nas suas diretrizes, estrutura interna, dotação orçamentária e capacidade de execução. Finalmente, o artigo analisa as parcerias engendradas pelo SENAES com outros programas governamentais que fazem interface com a economia solidária, com vistas a aumentar a aderência do tema no interior do governo federal. A análise sugere que o modelo de Kingdon explica o processo de inserção da economia solidária como política pública em 2003, ainda que essa inserção seja apenas uma etapa do seu ciclo. Definida sua constituição normativa, nota-se uma disputa do programa no interior do governo: passados oito anos, não se observou uma intervenção efetiva do governo ao ponto de consolidar as práticas socioeconômicas - difundidas pela economia solidária - como estratégia real para a inserção no mundo do trabalho, ou mesmo criar um ambiente institucional que incentive a formalização dos grupos econômicos associativos existentes. Em que pese sua baixa dotação orçamentária face a outros programas do MTE, o PESD não se constituiu em um programa de referência para uma nova estratégia de desenvolvimento, mesmo que a SENAES tenha conseguido aglutinar ao seu entorno forças sociais e políticas importantes para a defesa da economia solidária enquanto política pública. O trabalho situa e problematiza a inserção e a condução das politicas de economia solidaria no governo federal, revelando que a temática não ascendeu ao macrossistema político, gravitando em um campo marginal, fora desse núcleo, em busca de espaço para sua valorização interna. Enquanto ela for encarada meramente como uma alternativa paliativa ao problema do desemprego, dificilmente conseguirá enfrentar os antagonismos e conflitos de interesse que impedem sua viabilização

Prevalence and determinants of chronic respiratory diseases in adults in rural Sudan

BACKGROUND: Chronic respiratory diseases (CRDs) are considered a significant cause of morbidity and mortality worldwide, although data from Africa are limited. This study aimed to determine the prevalence and determinants of CRDs in Khartoum, Sudan. METHODS: Data were collected from 516 participants aged ≥40 years, who had completed a questionnaire and undertook pre- and post-bronchodilator spirometry testing. Trained field workers administered the questionnaires and conducted spirometry. Survey-weighted prevalence of respiratory symptoms and spirometric abnormalities were estimated. Regression analysis models were used to identify risk factors for chronic lung diseases. RESULTS: Using the Third National Health and Nutrition Examination Survey, 1988–1994 (NHANES III) reference equations, the prevalence of chronic airflow obstruction (CAO) was 10%. The main risk factor was older age, 60–69 years (OR 3.16, 95% CI 1.20–8.31). Lower education, high body mass index and a history of TB were also identified as significant risk factors. The prevalence of a low forced vital capacity (FVC) using NHANES III was 62.7% (SE 2.2) and 11.3% (SE 1.4) using locally derived values. CONCLUSION: The prevalence of spirometric abnormality, mainly low FVC, was high, suggesting that CRD is of substantial public health importance in urban Sudan. Strategies for the prevention and control of these problems are needed

Crystallization And Preliminary X-ray Study Of Haem-binding Protein From The Bloodsucking Insect Rhodnius Prolixus.

Rhodnius haem-binding protein (RHBP) from the bloodsucking insect Rhodnius prolixus, a 15 kDa protein, has been crystallized using polyethylene glycol as a precipitant. X-ray diffraction data have been collected at a synchrotron source. The crystals belong to the space group P4(1(3))2(1)2, with unit-cell parameters a = b = 64.98, c = 210.68 A, and diffract beyond 2.6 A resolution.57860-

Crystal structures of beta-galactosidase from Penicillium sp. and its complex with galactose

Beta-galactosidases catalyze the hydrolysis of beta(1-3) and beta(1-4) galactosyl bonds in oligosaccharides as well as the inverse reaction of enzymatic condensation and transglycosylation. Here we report the crystallographic structures of Penicillium sp. beta-galactosidase and its complex with galactose solved by the SIRAS quick cryo-soaking technique at 1.90 A and 2.10 A resolution, respectively. The amino acid sequence of this 120 kDa protein was first assigned putatively on the basis of inspection of the experimental electron density maps and then determined by nucleotide sequence analysis. Primary structure alignments reveal that Penicillium sp. beta-galactosidase belongs to family 35 of glycosyl hydrolases (GHF-35). This model is the first 3D structure for a member of GHF-35. Five distinct domains which comprise the structure are assembled in a way previously unobserved for beta-galactosidases. Superposition of this complex with other beta-galactosidase complexes from several hydrolase families allowed the identification of residue Glu200 as the proton donor and residue Glu299 as the nucleophile involved in catalysis. Penicillium sp. beta-galactosidase is a glycoprotein containing seven N-linked oligosaccharide chains and is the only structure of a glycosylated beta-galactosidase described to date

Expression, purification, crystallization and preliminary X-ray analysis of YaeQ (XAC2396) from Xanthomonas axonopodis pv. citri

The first crystallographic study of a member of the YaeQ family of proteins, which are conserved in a small group of Gram-negative bacteria, most of which are animal or plant pathogens, is reported. Diffraction data were collected to 1.9 Å resolution and an interpretable electron-density map was obtained