2,582 research outputs found
DOES AEROBIC EXERCISE TRAINING PROMOTE CHANGES IN STRUCTURAL AND BIOMECHANICAL PROPERTIES OF THE TENDONS IN EXPERIMENTAL ANIMALS? A SYSTEMATIC REVIEW
To develop a systematic review to evaluate, through the best scientific evidence available, the effectiveness of aerobic exercise in improving the biomechanical characteristics of tendons in experimental animals. Two independent assessors conducted a systematic search in the databases Medline/PUBMED and Lilacs/BIREME, using the following descriptors of Mesh in animal models. The ultimate load of traction and the elastic modulus tendon were used as primary outcomes and transverse section area, ultimate stress and tendon strain as secondary outcomes. The assessment of risk of bias in the studies was carried out using the following methodological components: light/dark cycle, temperature, nutrition, housing, research undertaken in conjunction with an ethics committee, randomization, adaptation of the animals to the training and preparation for the mechanical test. Eight studies, comprising 384 animals, were selected; it was not possible to combine them into one meta-analysis due to the heterogeneity of the samples. There was a trend to increasing ultimate load without changes in the other outcomes studied. Only one study met more than 80% of the quality criteria. Physical training performed in a structured way with imposition of overloads seems to be able to promote changes in tendon structure of experimental models by increasing the ultimate load supported. However, the results of the influence of exercise on the elastic modulus parameters, strain, transverse section area and ultimate stress, remain controversial and inconclusive. Such a conclusion must be evaluated with reservation as there was low methodological control in the studies included in this review
Numerical modelling of the punching behaviour of steel fibre reinforced self-compacting concrete flat slabs
Punching shear failure on flat reinforced concrete slabs of residential and commercial
buildings is generally avoided by using transversal reinforcement and/or chapiters. The
first option requires intense labour, mainly when densely flexural reinforcement exists in
the potential punching failure region, with detrimental consequences in terms of costs of
this construction solution. The second option has also extra costs due to the necessity of
special arrangements of moulds for casting the chapiters. The interference of a chapiter on
the flatness of the slab can also be a negative aspect from the architectonic point of view.
The use of steel fibre reinforcement can be a solution to avoid both the conventional
punching reinforcement and chapiters. Therefore, an experimental program was carried
out to assess the potentialities of steel fibre reinforced self-compacting concrete (SFRSCC)
for the punching resistance of flat slabs centrically loaded. This experimental program is
described, and the main results are presented and analysed. To assess the potentialities of
the Reissner-Mindlin FEM-based theory for modelling the behaviour of flat SFRSCC slabs
submitted to punching loading configuration, new features were introduced in the out-ofplane
shear constitutive law of the SFRSCC. These features are briefly described and the
main focus was given on the modelling strategy adopted for simulating the punching tests.Fundação para a Ciência e a Tecnologia (FCT
Numerical simulation of the punching shear behaviour of self-compacting fibre reinforced flat slabs
This paper presents the numerical simulations of the punching behaviour of centrally loaded steel fibre reinforced self-compacting concrete (SFRSCC) flat slabs. Eight half scaled slabs reinforced with different content of hooked-end steel fibres (0, 60, 75 and 90 kg/m3) and concrete strengths of 50 and 70 MPa were tested and numerically modelled. Moreover, a total of 54 three-point bending tests were carried out to assess the post-cracking flexural tensile strength. All the slabs had a relatively high conventional flexural reinforcement in order to promote the occurrence of punching failure mode. Neither of the slabs had any type of specific shear reinforcement rather than the contribution of the steel fibres. The numerical simulations were performed according to the Reissner-Mindlin theory under the finite element method framework. Regarding the classic formulation of the Reissner-Mindlin theory, in order to simulate the progressive damage induced by cracking, the shell element is discretized into layers, being assumed a plane stress state in each layer. The numerical results are, then, compared with the experimental ones and it is possible to notice that they accurately predict the experimental force-deflection relationship. The type of failure observed experimentally was also predicted in the numerical simulations.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and
National Funds through FCT - Portuguese Foundation for Science and Technology under the project “SlabSys – HFRC –
Flat slabs for multi-storey buildings using hybrid reinforced self-compacting concrete: an innovative structural system”
PTDC/ECM/120394/2010
Development of a Solar Panel Control Strategy for Tracking Maximum Power Generation / Desenvolvimento de uma estratégia de controlo de painéis solares para rastrear a produção máxima de energia
The solar panel is an essential energy conversion component of photovoltaic (PV) systems, an indispensable key for converting clean and sustainable solar energy into electricity. Over the last few years, there has been a growing demand for renewable sources due to sustainable development and global warming. Therefore, this work describes the prototype of an electronic supervision and control system for the orientation of a bench solar panel. The developed tracker prototype has as its core an electronic circuit based on a commercial microcontroller model Tennsy 3.0, within which the control algorithm is embedded. In addition to the controller, a supervisory software was developed to monitor solar cells’ status in real-time. The supervisory showed the angle of the solar plate and values of luminosity and acquired power. Simulations results were presented to show that the amount of energy generated can reach 37 %.
Caso fatal de adiaspiromicose pulmonar humana
A fatal case of human pulmonary adiaspiromycosis is reported. The patient, a male farm laborer from Pernambuco, in the Northeastern part of Brazil, had moved to Planaltina, DF., one year prior the onset of his illness. The main clinical manifestations consisted in fever, myalgia, cough and dyspnea. After being sick for five weeks, the patient developed severe respiratory failure and died. Grossly, disseminated nodular lesions, a few millimeters in diameter, were observed throughout the lobes of both lungs. Microscopically, round structures, up to 600 /mi in diameter, with a thick membrane, identified as adiaconidia of Chrysosporium parvum var. crescens, were seen in the center of the nodular lesions. These adiaconidia appeared predominantly inside microabscesses or necrotic areas, both surrounded by a granulomatous reaction. The pulmonary alveoli not affected by the nodular lesions contained an inflammatory exudate composed of macrophages and neutrophils. The finding of several non-fatal cases of the disease in the area of the Federal District suggests that adiaspiromycosis is endemic in the Central Brazilian Plateau region, where the dry, warm and windy climate, particulary from August to October, may provide the appropriate environmental conditions for the dissemination of C. parvum conidia.É descrito um caso fatal de adiaspiromicose pulmonar, em paciente do sexo masculino, lavrador, que vivia em Planaltina-DF, para onde se mudara, vindo do Nordeste, cerca de um ano antes do aparecimento da enfermidade. As manifestações principais consistiram em febre, calafrios, mialgias, tosse seca e dispnéia. Após cinco semanas, o paciente faleceu, devido a insuficiência respiratória. Na autópsia, lesões nodulares incontáveis, medindo alguns milímetros de diâmetro, apareciam disseminadas por todos os lobos de ambos os pulmões. O exame microscópico revelou a existência, dentro dos nódulos, de estruturas redondas, volumosas (atingiam até 600 /tm de diâmetro), providas de membrana espessa, e identificadas como adiaconídios de Chrysosporium parvum var. crescens. Esses adiaconídios eram sempre encontrados no interior de microabscessos ou de áreas de necrose tissular, ambos cercados por reação granulomatosa. Os alvéolos pulmonares, não comprometidos pelos nódulos, apresentavam-se cheios de células da inflamação, principalmente macrófagos e neutrófilos. O achado de outros casos, não fatais, da doença, nos arredores de Brasília, indica que a adiaspiromicose deve ser endêmica na região do Planalto Central brasileiro, lugar onde o clima, principalmente nos meses de agosto a outubro, é quente e seco, com ventos fortes, fatores que devem contribuir para a disseminação dos conídios de C. parvum
Evaluation of the aquatic macroinvertebrate community as a tool for monitoring a reservoir in the Pitangui river basin, Paraná, Brazil
Os macroinvertebrados bentônicos e nectônicos representam elementos importantes na estrutura e funcionamento dos ecossistemas aquáticos e sua distribuição é influenciada pela natureza química do substrato, composição da vegetação e profundidade da lâmina d'água. O conhecimento desta fauna contribui para a avaliação da qualidade da água e a elaboração de ações visando à conservação da biodiversidade. No presente estudo foram avaliadas diferentes medidas bióticas da comunidade de invertebrados da represa de Alagados, importante manancial da cidade de Ponta Grossa, no Paraná. Em cinco diferentes pontos de amostragem, foram coletados 18.473 exemplares de macroinvertebrados aquáticos ou semi-aquáticos, pertencentes a 46 táxons dos filos Annelida (Hirudinea e Oligochaeta), Mollusca (Gastropoda), Platyhelminthes (Turbellaria), Nematoda e Arthropoda (Arachnida, Crustacea e Insecta). Esta comunidade foi constituída predominantemente por organismos predadores (45,7% dos táxons amostrados), seguidos de coletores e/ou filtradores (23,9%); raspadores (15,2%), fragmentadores (13%) e detritívoros (2,2%). De modo geral, os índices de diversidade (H') e equitabilidade (J) foram significativamente baixos para os cinco locais investigados, com H' variando de 0,3301 a 1,0396. Quanto à tolerância dos organismos à poluição orgânica, alguns táxons mais sensíveis foram muito raros (Plecoptera) ou em baixa frequência (Trichoptera e Ephemeroptera). Entre os grupos mais resistentes a ambientes poluídos estão os Chironomidae e os Hirudinea, ambos bastante comuns nas amostras de Alagados. Este estudo reforça a importância da análise de bioindicadores na avaliação da qualidade de água para consumo humano e também para a conservação de ecossistemas, considerando que um programa de monitoramento ambiental deve integrar medidas físicas, químicas e biológicas.Benthic and nektonic macroinvertebrates play an important role in the structure and function of aquatic ecosystems and their distribution is influenced by chemical features of the substrate, vegetation composition, and water depth. Knowledge on the fauna contributes to the assessment of water quality and development of biodiversity conservation activities. Different biotic factors affecting the invertebrate community were evaluated in the Alagados reservoir, the main water source of the city of Ponta Grossa, Paraná. In five different sampling points, 18,473 specimens of aquatic or semiaquatic macroinvertebrates were collected, belonging to 46 taxa of the phylla Annelida (Hirudinea and Oligochaeta), Mollusca (Gastropoda), Platyhelminthes (Turbellaria), Nematoda and Arthropoda (Arachnida, Crustacea and Insecta). This community was composed mainly of predators (45.7% of the taxa sampled), collectors and/or filterers (23.9%), scrapers (15.2%), shredders (13.0%) and detritivores (2.2%). Diversity (H') and evenness (J) indices were significantly low for the sites examined, and H' ranged between 0.3301 and 1.0396. Regarding tolerance of organisms to organic pollution, more sensitive taxa were very rare (Plecoptera) or unusual (Trichoptera and Ephemeroptera). Among the more resistant groups are Chironomidae and Hirudinea, both fairly common in the samples. This study corroborates the importance of bioindicators as a tool to assess water quality for human consumption and for the conservation of aquatic environments, integrating physical, chemical and biological factors in monitoring programs
Diagnosis of \u3ci\u3eSchistosoma mansoni\u3c/i\u3e Infections: What are the Choices in Brazilian Low-Endemic Areas?
The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then subsequent confirmation of positive cases by intensive parasitological investigations
Quantificação da variabilidade genética entre matrizes de Coffea canephora das variedades botânicas Conilon e Robusta.
O objetivo desse trabalho foi quantificar a divergência genética entre 130 acessos clonais de Coffea canephora das variedades botânicas Conilon, Robusta e híbridos interespecíficos.bitstream/item/216339/1/cpafro-18440-bdp-77.pd
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