Vortex motion around a circular cylinder above a plane

The study of vortex flows around solid obstacles is of considerable interest from both a theoretical and practical perspective. One geometry that has attracted renewed attention recently is that of vortex flows past a circular cylinder placed above a plane wall, where a stationary recirculating eddy can form in front of the cylinder, in contradistinction to the usual case (without the plane boundary) for which a vortex pair appears behind the cylinder. Here we analyze the problem of vortex flows past a cylinder near a wall through the lenses of the point-vortex model. By conformally mapping the fluid domain onto an annular region in an auxiliary complex plane, we compute the vortex Hamiltonian analytically in terms of certain special functions related to elliptic theta functions. A detailed analysis of the equilibria of the model is then presented. The location of the equilibrium in front of the cylinder is shown to be in qualitative agreement with the experimental findings. We also show that a topological transition occurs in phase space as the parameters of the systems are variedComment: 17 pages, 8 figure

A SUSTENTABILIDADE FINANCEIRA DA UFS: ENTRAVES E ALTERNATIVAS

Este trabalho tem como objetivo analisar a composição dos recursos da Universidade Federal de Sergipe (UFS) apresentando os entraves e alternativas para ampliar a captação da receita. Explana uma abordagem histórica dos valores e fatos que definiram as fontes consolidadas de recursos no período de 1998 a 2008 da UFS e evidencia a importância do financiamento como lastro de sustentabilidade às políticas públicas educacionais. Para desenvolvimento da pesquisa foram utilizados os seguintes recursos: bibliografias inerentes ao tema, documentos contábeis extraídos do Sistema de Administração Financeira (SIAFI), do Governo Federal e, os Relatórios de Gestão do período compreendido neste trabalho. Dentre os resultados obtidos, destacam-se os seguintes: a captação de recursos por meio de descentralização de crédito, oriundos de projetos e parcerias, é uma alternativa para majorar os créditos orçamentários da instituição, posto que a dotação liberada pelo governo é limitada e; a UFS poderia, ainda, implementar a estratégia de inteligência para captação de recursos por meio de doações. Com relação à capacidade de execução orçamentária, a instituição praticamente realiza plenamente sua dotação

Muscidae (Diptera) of medico-legal importance associated with ephemeral organic substrates in seasonally dry tropical forests

Muscidae (Diptera) comprises one of the most important taxa in medical, veterinary and forensic entomology, especially due to their association with decomposing carcasses and cadavers. Yet, knowledge on their distribution and behaviour is still incipient in several biomes, which is the case of dry tropical forests. This study aimed to evaluate the attractiveness of different organic substrates to species of Muscidae in areas of seasonally dry forests (Caatinga) in Northern Brazil. Sampling was carried out in five Caatinga areas between 2015 and 2017, using suspended traps baited with bovine spleen, fish or human faeces. When all samplings were combined, 3,176 adults of nine species were collected. The assemblages of muscids had higher richness and abundances on bovine spleen, which attracted 66% of all specimens, when compared to the other substrates. Musca domestica was the most abundant species, and it was dominant in assemblages associated with spleen and fish. Assemblages attracted to spleen and fish had higher similarity, differing from those associated with faeces. Differences in food attractiveness are presented for species of medical interest as pathogen vectors (e.g., Synthesiomyia nudiseta (Wulp, 1883)) and of forensic relevance as colonizers of human corpses (e.g., Ophyra aenescens (Wiedemann, 1830))

Muscidae (Diptera) of medico-legal importance associated with ephemeral organic substrates in seasonally dry tropical forests

Muscidae (Diptera) comprises one of the most important taxa in medical, veterinary and forensic entomology, especially due to their association with decomposing carcasses and cadavers. Yet, knowledge on their distribution and behaviour is still incipient in several biomes, which is the case of dry tropical forests. This study aimed to evaluate the attractiveness of different organic substrates to species of Muscidae in areas of seasonally dry forests (Caatinga) in Northern Brazil. Sampling was carried out in five Caatinga areas between 2015 and 2017, using suspended traps baited with bovine spleen, fish or human faeces. When all samplings were combined, 3,176 adults of nine species were collected. The assemblages of muscids had higher richness and abundances on bovine spleen, which attracted 66% of all specimens, when compared to the other substrates. Musca domestica was the most abundant species, and it was dominant in assemblages associated with spleen and fish. Assemblages attracted to spleen and fish had higher similarity, differing from those associated with faeces. Differences in food attractiveness are presented for species of medical interest as pathogen vectors (e.g., Synthesiomyia nudiseta (Wulp, 1883)) and of forensic relevance as colonizers of human corpses (e.g., Ophyra aenescens (Wiedemann, 1830))

Development of Plasmonic Nanosandwiches for Biosensing Applications

Structures composed of two gold disks with different diameters and separated by a thin alumina layer were studied for protein biodetection. The small top disk will be used as the biosensing element since it has a shorter decay length (and thus, it has a higher sensitivity) whereas the big bottom one will give a high signal due to its bigger interaction with light. The interaction between both disks will happen through plasmon hybridisation. The samples were prepared using colloidal lithography and material deposition was made through an electron beam assisted evaporation system. A fabrication method was developed to spatially isolate the bottom disk from the sensing medium to fully exploit the small disk’s higher sensitivity. Sample’s characterisation consisted in a morphologic analysis by scanning electronic microscopy (SEM), the optical response was studied experimentally and by finite-domain time-difference (FDTD) simulations and also the electric field distribution was analysed in three types of structures. Structures with the upper disk centred relative to the lower disk and at the edge of it. The oxide’s thickness effect was studied (3 and 6 nm). The low energy peak is mainly given by a plasmonic gap dipole mode, whereas as the high energy peak is given by a contribution from a gap mode and the structure’s overall net dipole. The structure with a smaller separation and the top disk centre regarding the bottom disk was found to have a higher electric field enhancement around it and should be the one to be used as a biosensor

Extrato de alho melhora a superação da dormência de videiras ‘Niagara Rosada’em regiões subtropicais.

Nas regiões com invernos amenos, normalmente as exigências de frio para a quebra de dormência de gemas de videiras não são atendidas, e apenas os produtos altamente tóxicos CaCN2 e H2CN2 são recomendados na viticultura convencional para quebra de dormência. A proposta deste estudo foi verificar o efeito do extrato de alho na quebra de dormência de videiras ‘Niagara Rosada’, em dois diferentes vinhedos. A dose mais elevada de extrato de alho (70mL L-1)demonstrou ter um grande potencial para a quebra de dormência na produção orgânica, apresentando efeitos similares aos das cianamidas, na quebra de dormência. Este tratamento aumentou a porcentagem de brotação e o número de cachos, antecipou o começo da brotação e reduziu o ciclo entre poda e colheita

Use of plant protection products in agriculture

Introduction: Agriculture is an activity practiced for thousands of years by humans for food production representing risks to the workers' health. These risks are present mainly due to the use of Plant Protection Products (PPP) that despite having benefits in getting food also entail disadvantages for their handlers, to consumers of food produced and also for the environment me to carry out an empirical evaluation of the use of PPP in agriculture. Objectives: Assess knowledge about the use and application of plant protection products in agriculture. Methods: Study exploratory was conducted in several companies in the agricultural sector in the north and centre of Portugal. As the target population were considered all workers who used PF in their work duties for a total of 46 employees to whom questionnaires were administered to collect information on the practices adopted by the workers as regards the labour use of PPP. The investigation lasted eight months, starting in October 2015 and ending in May 2016. Results: The application of this research has shown the good practices adopted by the workers who were questioned and which are reading the labels, use of equipment for individual safety and proceed the correct disposal of waste of empty containers of PPP. However it can be noted that there are still aspects that the workers have to improve awareness level about the risk they are exposed to when handling PPP since not all employees were careful to adopt these good agricultural practices. Conclusions: The results also demonstrate the need for further action by the supervisory bodies to ensure that the PPP applicators have all the required training certificate by law. It should also be created more awareness campaigns about the safety issues when these products are used like the importance of reading labels, use of appropriate equipment for individual safety for each product type and exposure, and properly route for the waste package.info:eu-repo/semantics/publishedVersio