Steel Cold-formed Trussed Girders with Joint Eccentricities - Improvements on Design and Performance by Numerical and Experimental Analysis

Long span light roof systems of industrial buildings are frequently designed with cold-formed steel members, leading to competitive solution which allows liberating useful internal space inside the building. This type of structural solution is usually cost saving if it is combined with standardization of the manufacturing process thus enabling specialized solution. This is the case of a family of trussed girders ranging from 0.6 to 1.8 m depth, developed by the steel structures manufacturer and addressed to a standard system for general application enabling to bridge up to 40 m span of light roof construction. Typical buckling behavior of the cold-formed members, with special emphasis to the unsymmetrical stiffened Z section chord members was investigated as well as the effect of the eccentricities in the joints. Numerical and experimental results allowed understanding the buckling behavior of these members as well as confirming its strength capacity. For this both axially compressed tests of the Z chord member and load test of a complete trussed beam were performed and the obtained results were applied to improve the structural design. The comparison between experimental results and those from the prescriptions of the Brazilian design code addressed to steel cold-formed structural members (direct strength method-based strength check) will be presented and commented. The obtained results allowed confirming the actual behavior and ultimate loading condition of the trussed girder

Polistes canadensis (Linnaeus, 1758) (Vespidae: Polistinae) in the Western Amazon: a Potential Biological Control Agent

Wasps of the genus Polistes (Vespidae: Polistinae) are eusocial, considered valuable biological control agents. The objective of this work was to determine the resources collected by Polistes canadensis wasps, evaluate their performance and importance as a natural enemy and possible agent of biological control in the Brazilian Amazon. Between October 8th and November 20th, 2014, 20 evaluations were performed, totalizing 101 hours of observations of the foraging activity of an aggregation out in stage of development post-emergence with approximately 50 adult individuals distributed in 15 colonies. Additionally, observations of the predatory activity of Polistes canadensis on Plutella xylostella on a small organic plantation of kale (Brassica oleracea L. var. acephala DC), were also made. During the evaluations 1742 returns were recorded, 11.72% of them with prey, 3.10% with plant fiber, 16.76% with nectar, 45.17% with water and 23.25% without any visible load. All the preys identified were classified as Lepidoptera, belonging to ten morphospecies. Only one morphospecies was identified as Spodoptera frugiperda, which was the most commonly resource used by the wasps in 37 % in immature feeding. Only returns with nectar had statistically significant difference between the evaluated schedules. Polistes canadensis wasps did not prey Plutella xylostella caterpillars. The wasp aggregation studied was able to prey an average of 10.2 caterpillars per day, which demonstrates the potential of this species for the biological control of pests in the Amazon region. © 2017 Universidade Estadual de Feira de Santana. All Rights Reserved

Sensitivity of the Immunohistochemistry technique in central nervous system fragments of cattle and horses naturally infected by rabies virus

A raiva é uma zoonose viral que acomete o sistema nervoso central (SNC) de mamíferos, considerada um grave problema de saúde pública. Herbívoros (bovinos e equinos) são frequentemente acometidos pela in-fecção após serem atacados por morcegos hematófagos (Desmodus rotundus). A técnica de imunofluorescência direta (IFD) realizada em tecidos frescos, recomendada pela Organização Mundial de Saúde (OMS), é utilizada para o diagnóstico da raiva. A técnica de imuno-histoquímica (IHQ) é utilizada para detectar antígenos em tecidos fixados, pelo uso de anticorpos monoclonais/policlonais. O objetivo deste trabalho foi avaliar a sensibilidade da IHQ na detecção de antígenos do vírus da raiva em amostras de SNC de herbívoros fixadas em formol, analisando a distribuição antigênica em diferentes fragmentos do SNC. Os resultados demonstraram concordância das técnicas de IFD e IHQ. A IHQ mostrou maior sensibilidade em amostras de bovinos em relação às de equinos, especialmente quando realizada em fragmentos de cerebelo e tronco encefálico. A detecção de antígeno nestes fragmentos foi mais consistente para ambas as técnicas, nas duas espécies. Estes resultados demonstram que a IHQ pode ser empregada para a vigilância epidemiológica da raiva, entretanto, recomenda-se cautela ao se empregar a IHQ para diagnóstico de doença em herbívoros, especialmente quando o fragmento encaminhado ao laboratório for apenas o hipocampo.Rabies is a viral zoonosis that causes disease in the central nervous system (CNS) of mammals and it is considered a serious problem of public health. Herbivorous (bovines and equines) are often infected after being attacked by vampire bats (Desmodus rotundus). The direct fluorescent antibody technique is used as a diagnostic test to detect viral antigens in fresh tissues and is recommended by the World Health Organization. The immunohistochemistry technique (IHC) is used to detect the viral antigen through the use of monoclonal/policlonal antibodies in formalin-fixed tissues. The aim of this work was to evaluate the sensitivity of the IHC in samples of CNS of herbivorous fixed in formol, analyzing the antigenic distribution in different fragments of the CNS. The results demonstrated good agreement between the two techniques for the rabies diagnosis. The IHC presented higher sensitivity in samples of cattle comparing to horse samples, especially in fragments of cerebellum and brain stem. These fragments demonstrated to be more suitable for antigen detection by both techniques in the two species. These data demonstrate that the IHC is suitable for rabies vigilance yet cautions should be taken in examining cattle and horses samples, when the submitted specimen is only the hippocampus

Combined effect of bumetanide, bromide, and GABAergic agonists: An alternative treatment for intractable seizures

Univ Fed Sao Joao del Rei, Lab Neurociencia Expt & Computac, Programa Inst Bioengn, Sao Joao Del Rei, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Expt Neurol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Fisiol, São Paulo, BrazilPontificia Univ Catolica Rio Grande do Su, Inst Cerebro, Porto Alegre, RS, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Expt Neurol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Fisiol, São Paulo, BrazilWeb of Scienc

Uniformity of water distribution in a central pivot with the use of the Time Domain Reflectometry technique on surface and soil

The evaluation of the uniformity of water distribution in an irrigation system is done above the surface of the soil. The main objective of this work was to evaluate the uniformity of water distribution in a central pivot under field conditions, through the use of the CUD and CUC coefficients. On the surface, the uniformity was obtained with the use of the ABNT methodology, therefore placing two collector lines displaced three degrees from the initial pivot position. In order to obtain the uniformity in the soil, the water content was determined with the TDR (Time Domain Reflectometry), which is a simple and fast technique. The results demonstrated that uniformity in the soil was greater than on the surface and above the recommended range. The water arrangement in the soil promotes that condition. Therefore in the economic design of irrigation systems, the uniformity coefficients in the soil should be considered.A avaliação da uniformidade de distribuição de água de um sistema de irrigação é feita acima da superfície do solo. Tendo em vista a importância da uniformidade no interior do solo quando submetido a uma irrigação, desenvolveu-se o presente trabalho com o objetivo de se avaliar a uniformidade de distribuição de água, tanto acima como no interior do solo, através dos coeficientes CUD e CUC, com um pivô central operando em condições de campo. Acima da superfície, a uniformidade foi obtida seguindo-se a metodologia da Associação Brasileira de Normas Técnicas (ABNT) e se alocando duas linhas de coletores com abertura de 3º, a partir do ponto inicial do pivô. Propôs-se, para obtenção da uniformidade no interior do solo, a utilização da umidade determinada pelo TDR (Reflectometria no Domínio do Tempo) visto que é uma técnica simples e produz resultados imediatos. Os resultados encontrados demonstraram que a uniformidade no interior do solo foi maior que na superfície, ficando acima da faixa recomendada, mostrando que a redistribuição da água no interior do solo promove maior uniformidade de umidade no perfil do solo que a encontrada na lâmina aplicada; portanto, no dimensionamento econômico de sistemas de irrigação, os coeficientes de uniformidade obtidos no interior do solo devem ser considerados.18719

Temporal patterns of the catadromous thinlip grey mullet migration in freshwater

The thinlip grey mullet (Chelon ramada Risso, 1827) is a catadromous fish that performs massive migrations to freshwater habitats for feeding purposes that can assume a structuring role on riverine ecology due to the biomass involved in these movements. Seasonal movements of thinlip grey mullet through a vertical slot fish pass located in River Mondego (Portugal) were continuously monitored between 2013 and 2017. The extent of trophic migration, population size structure, biomass and the environmental triggers of bi-directional species' migratory activity were analysed. Between March and November of 2013/2014, ~2 million and 1 million movements were respectively recorded. From a subsampling approach, the upstream movements between 2015 and 2017 were estimated. Annually, around five hundred thousand upstream movements can occur to provide species access to the upstream freshwater reaches. Movements are exclusively diurnal, and the population composed by young adults in their first year of maturity, yet juveniles and larger fish were present (TL range: 90–540 mm). Upstream movements increased with temperatures above 15°C, reaching a peak at around 20°C coupled with a photoperiod of 15 h. Downstream movements attained the higher rates when temperature dropped from 22°C to 20°C and photoperiod to 13 h. However, under wetter hydrological conditions (as in 2014), discharge flows have a higher influence. These finding provide unique information regarding species migration to freshwater habitats in the Atlantic coast, namely the extended periods spent in such environments, overlapping with the spawning migration period. Additionally, highlights the importance of species' trophic migration both for its life cycle and riverine food-web

Bistable Firing Pattern in a Neural Network Model

Excessively high, neural synchronization has been associated with epileptic seizures, one of the most common brain diseases worldwide. A better understanding of neural synchronization mechanisms can thus help control or even treat epilepsy. In this paper, we study neural synchronization in a random network where nodes are neurons with excitatory and inhibitory synapses, and neural activity for each node is provided by the adaptive exponential integrate-and-fire model. In this framework, we verify that the decrease in the influence of inhibition can generate synchronization originating from a pattern of desynchronized spikes. The transition from desynchronous spikes to synchronous bursts of activity, induced by varying the synaptic coupling, emerges in a hysteresis loop due to bistability where abnormal (excessively high synchronous) regimes exist. We verify that, for parameters in the bistability regime, a square current pulse can trigger excessively high (abnormal) synchronization, a process that can reproduce features of epileptic seizures. Then, we show that it is possible to suppress such abnormal synchronization by applying a small-amplitude external current on > 10% of the neurons in the network. Our results demonstrate that external electrical stimulation not only can trigger synchronous behavior, but more importantly, it can be used as a means to reduce abnormal synchronization and thus, control or treat effectively epileptic seizures.Peer Reviewe

Unpredictability in seasonal infectious diseases spread

In this work, we study the unpredictability of seasonal infectious diseases considering a SEIRS model with seasonal forcing. To investigate the dynamical behaviour, we compute bifurcation diagrams type hysteresis and their respective Lyapunov exponents. Our results from bifurcations and the largest Lyapunov exponent show bistable dynamics for all the parameters of the model. Choosing the inverse of latent period as control parameter, over 70% of the interval comprises the coexistence of periodic and chaotic attractors, bistable dynamics. Despite the competition between these attractors, the chaotic ones are preferred. The bistability occurs in two wide regions. One of these regions is limited by periodic attractors, while periodic and chaotic attractors bound the other. As the boundary of the second bistable region is composed of periodic and chaotic attractors, it is possible to interpret these critical points as tipping points. In other words, depending on the latent period, a periodic attractor (predictability) can evolve to a chaotic attractor (unpredictability). Therefore, we show that unpredictability is associated with bistable dynamics preferably chaotic, and, furthermore, there is a tipping point associated with unpredictable dynamics