822 resultados para risky choice
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This study evaluated anteroposterior trunk movements and the time spent on activities of load-carrying to surfaces at different heights, among experienced and inexperienced individuals. Thirty-six healthy males (16 experienced and 20 inexperienced in load-carrying) had their trunk movements recorded by an electrogoniometer while transporting boxes (7 and 15 kg) to surfaces of variable heights (low, low intermediate, high intermediate and high). Longer time was spent on trunk flexion when carrying loads to low surfaces and on trunk extension when carrying to high surfaces (p<0.05). Differences in time spent on trunk flexion/extension were identified between loads, and between groups for the heavier load. There were no differences in flexion/extension amplitudes between groups or loads. Although unnecessary flexion/extension occurring prior to a task may increase the exposure of the trunk to risky movements, the amplitudes reported here were relatively small and seemed to have occurred to facilitate the final tasks.Relevance to industryLifting devices and technological assistance are increasingly available in industrial settings. However, distribution centers and delivery services represent new demands on workers and involve an expressive amount of manual handling and carrying activities. Thus, studies on carrying strategies are necessary as they can provide guidelines for safer activities. (C) 2007 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Children's labour as a risky pathways to resilience: children's growth in contexts of poor resources
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Nesse artigo, analisamos a questão do trabalho infantil como um fenômeno complexo, englobando fatores de risco por um lado e possíveis resultados positivos por outro. Baseados na teoria da resiliência e a partir de uma revisão de literatura, centrada em pesquisas que analisam a própria experiência de crianças sobre o trabalho desenvolvido, mostramos que quando inseridos em ecologias socialmente e fisicamente pobres em recursos, crianças associam sua experiência de trabalho como um caminho para assegurar recursos próprios para superação de adversidades. A compreensão de aspectos subjetivos da experiência de crianças trabalhadores nos permite considerar o trabalho como uma construção culturalmente embasada. Apesar da exploração de crianças não se configurar como o melhor para elas, há evidências de que elas usam quaisquer oportunidades disponíveis, incluindo o trabalho, para navegar em busca de recursos que necessitam e negociam por uma identidade associada à resiliência. Implicações para políticas públicas e intervenções também são discutidas.
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As substâncias traçadoras são usadas para avaliar a eficácia de pulverizações mas, normalmente, elas modificam a tensão superficial de soluções aquosas. O trabalho objetivou definir um método para avaliar a distribuição e a quantidade de produto depositada em pulverizações, utilizando-se substâncias traçadoras, com a possibilidade de ajustar a tensão superficial da calda. Foram testados os produtos Azul Brilhante a 0,15%, Saturn Yellow a 0,15% suspenso em lignosulfonato Vixilperse a 0,015% e a Fluoresceína Sódica a 0,005%, e as misturas de Azul Brilhante mais Saturn Yellow e Azul Brilhante mais Fluoresceína, nas mesmas concentrações. Para avaliar a degradação as soluções com os produtos foram depositados sobre folhas de citros e avaliados as quantidades através da leitura de unidade de fluorescência e densidade óptica, das soluções sem secar, secas no escuro, exposta ao sol por 2, 4 e 8 horas e comparadas com as leituras obtidas com os depósitos direto em água. A tensão superficial da solução traçadora foi determinada pela passagem de gotas formadas no período entre 20 e 40 segundos. A mistura do Azul Brilhante mais o Saturn Yellow a 0,15%, não apresentou degradação em todas as condições de avaliação, não foi absorvida pelas folhas e manteve a solução na mesma tensão superficial da água, possibilitando ajustá-la aos mesmos níveis das concentrações dos produtos fitossanitários. Isto proporcionou o estabelecimento de um método qualitativo pela avaliação visual sobre luz ultravioleta da distribuição do pigmento e quantitativo com a determinação da quantidade depositada do corante numa mesma solução, em diferentes tensões superficiais na calda de pulverização.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Dairy cows often have to choose which of two sides to enter in the milking parlour. Some cows are very consistent in this choicė, and it is common to assume that when these cows are more disturbed are being milked in their non-preferred side. Such disturbance might involve significantly poor welfare. In order to assess this assumption, we decided to study the behaviour and milk yield of dairy cows and their relationships with side preference in the milking parlour. The study was carried out at Cambridge University Farm, in a two-sided tandem milking parlour. The data collection followed the daily management routine. We recorded the side chosen by each cow (left or right) during 40 milking sessions. Data from 70 cows, which were present in at least 25 milking sessions (mode = 36), were included in the statistical analysis. Cows' reactivity (CR) during premilking udder preparation, time spent fitting the milking cluster (FT), milk yield (MY) and duration of milking (DM) were measured. There was evident individual variation in the consistency of side choice. Individual differences (ANOVA, P < 0.001) were also found in CR, FT, MY and DM; although these variables were not significantly affected by the side or the interaction animal × side (ANOVA, P < 0.05). The comparison between left and right side means (paired t-test) of these variables did not show significant differences (P < 0.05). We concluded that there is no evidence that the cows were discomforted or stressed when milked in the non-preferred side of the milking parlour. © 2001 Elsevier Science B.V.
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A recent theory suggests that economic considerations are more important than genetic ones in the emergence and maintenance of social behavior. Evolution of social behavior in wasps, thus, could be based on the development of worker castes, which increase the efficiency of brood care and energy use of the colony. If so, social wasps should collect a larger range of prey, favoring polyethism, as social behavior should increase the adaptive value of social species among wasps by increasing the range of prey accessible. We explored the literature and showed that the Eumeninae, which are mostly solitary, draw prey from significantly fewer orders of arthropods than wasps in the subfamily Vespinae and Polistinae, which are mainly social, supporting the hypothesis that social behavior may have emerged as a more efficient way to feed and care for the young by opening a wider range of food sources, increasing the amount of food and quality of care provided to the young. Two alternative explanations of this data are also discussed.
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Includes bibliography
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Goal Programming (GP) is an important analytical approach devised to solve many realworld problems. The first GP model is known as Weighted Goal Programming (WGP). However, Multi-Choice Aspirations Level (MCAL) problems cannot be solved by current GP techniques. In this paper, we propose a Multi-Choice Mixed Integer Goal Programming model (MCMI-GP) for the aggregate production planning of a Brazilian sugar and ethanol milling company. The MC-MIGP model was based on traditional selection and process methods for the design of lots, representing the production system of sugar, alcohol, molasses and derivatives. The research covers decisions on the agricultural and cutting stages, sugarcane loading and transportation by suppliers and, especially, energy cogeneration decisions; that is, the choice of production process, including storage stages and distribution. The MCMIGP allows decision-makers to set multiple aspiration levels for their problems in which the more/higher, the better and the less/lower, the better in the aspiration levels are addressed. An application of the proposed model for real problems in a Brazilian sugar and ethanol mill was conducted; producing interesting results that are herein reported and commented upon. Also, it was made a comparison between MCMI GP and WGP models using these real cases. © 2013 Elsevier Inc.
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Incluye Bibliografía
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Includes bibliography
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)