726 research outputs found

    Selection of native trees for intercropping with coffee in the Atlantic Rainforest biome

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    A challenge in establishing agroforestry systems is ensuring that farmers are interested in the tree species, and are aware of how to adequately manage these species. This challenge was tackled in the Atlantic Rainforest biome (Brazil), where a participatory trial with agroforestry coffee systems was carried out, followed by a participatory systematisation of the farmers experiences. Our objective was to identify the main tree species used by farmers as well as their criteria for selecting or rejecting tree species. Furthermore, we aimed to present a specific inventory of trees of the Leguminosae family. In order to collect the data, we reviewed the bibliography of the participatory trial, visited and interviewed the farmers and organised workshops with them. The main farmers' criteria for selecting tree species were compatibility with coffee, amount of biomass, production and the labour needed for tree management. The farmers listed 85 tree species; we recorded 28 tree species of the Leguminosae family. Most trees were either native to the biome or exotic fruit trees. In order to design and manage complex agroforestry systems, family farmers need sufficient knowledge and autonomy, which can be reinforced when a participatory methodology is used for developing on-farm agroforestry systems. In the case presented, the farmers learned how to manage, reclaim and conserve their land. The diversification of production, especially with fruit, contributes to food security and to a low cost/benefit ratio of agroforestry systems. The investigated agroforestry systems showed potential to restore the degraded landscape of the Atlantic Rainforest biome

    Distributed situation awareness in nuclear, chemical, and maritime domains

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    The increase in size, automation and complexity of modern sociotechnical systems changed the dynamics of work environments and calls for new methodologies and metaphors towards safety of complex systems. Chemical, nuclear, and transportation (i.e. road, maritime, and aviation) industries are composed of various nested sub-systems where smooth coordination and communication are essential features to achieve continuous and safe operations. Even though such sub-systems exist since the industrial revolution, fewer studies have been conducted in these domains: to understand the work as it is done (rather than it is imagined), which is the only way to shed light about the variability in work performance and how these subsystems can combine to generate dangerous and unexpected outcomes. The theoretical framework of Distributed Situation Awareness provides a firm background to investigate the sub-systems that constitute the chemical, nuclear, and maritime industries/domains. This paper unfolds the key sub-systems (e.g., operators, human-computer interfaces, communication tools, and distant/different locations) that play a critical role in normal and abnormal situations in these industries. The complex interconnections among various artifacts are explained and their significance is assessed

    Use Dosimetry Virtual Tool for Security Studies Physics and Nuclear

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    AbstractThe objective of this work is to develop a virtual detection tool of radioactive sources, such as to facilitate and assist the training and nuclear security planning. To accomplish this tool was created a virtual model of the Nuclear Engineering Institute (IEN) with virtual characters (avatars), able to move and interact with the environment, radiation detectors (fixed and portable) and sources radioactive. A tool developed enabled the simulation where individuals who were carrying radioactive sources were identified through the detectors installed at strategic points in the virtual environment. Furthermore, it was possible to detect and locate sources for handling portable detectors, operated by the characters within the virtual environment. The results showed a radiation detection system before the continuous profile radioactive sources, making it possible to evaluate the dose rate at any position of the virtual environment. So this work could help in both the security agents training and in the evaluation of the radiological safety of a nuclear site

    Thermal analysis of cement panels with lignocellulosic materials for building

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    The use of lignocellulosic material residue in cement composites can be considered as a good option because they allow good thermal behaviour. This paper aimed to compare three kinds of cement panels reinforced with different lignocellulosic materials (Coffee husk, Coconut shell, and Banana pseudostem) based on their thermal properties. To produce each panel, the methodology suggested by Souza (1994) was used. Six replicates of each lignocellulosic panel with dimensions of 7.0×7.5 were evaluated. The thermal analysis was performed in a chamber composed of MDP (medium density particleboard). The chamber contained the heat source (incandescent lamp) connected to a thermostat that maintained the temperature at 48.0 °C. The porosity and thickness of the panels and the thermal behaviour of each sample panel (thermal conductivity, resistivity, resistance, and transmittance) and the difference in temperature of both sides of the panel were evaluated. The temperature difference to stabilization was obtained after a sampling time of 200 minutes, with 1,000 readings of 12 s each. Although all the panels were submitted under the same temperature, the inner and external superficial temperatures of the coffee husk panels reached smaller values. Besides, coconut and banana pseudostem panels presented the best results of thermal transmittance and thermal resistance. Thus, coconut shell panels present the best thermal performance, which means that this panel might be an attractive alternative building material, in terms of heat insulation for indoor applications

    Wolbachia pipientis: first detection in populations of Glycaspis brimblecombei (Hemiptera: Aphalaridae) and Psyllaephagus bliteus (Hymenoptera: Encyrtidae) in Brazil

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    The sucking insect, Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), is originally from Australia and reduces the productivity of Eucalyptus crops. The parasitoid Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is the main agent used in the integrated management of G. brimblecombei. Endosymbionts, in insects, are important in the adaptation and protection of their hosts to the environment. The intracellular symbionts Wolbachia, induces reproductive changes such as cytoplasmic incompatibility, feminization, male death and parthenogenesis. The objective of this study was to report the first record of Wolbachia pipientis in populations of G. brimblecombei and of its parasitoid P. bliteus in the field in Brazil. Branches with adults of G. brimblecombei and P. bliteus were collected from eucalyptus trees in commercial farms in six Brazilian states and, after emergence, the insects obtained were frozen at -20 °C. Polymerase chain reaction (PCR) was performed to detect the Wolbachia endosymbiont. Wolbachia pipientis was identified in individuals of G. brimblecombei and its parasitoid P. bliteus from populations of the counties of Agudos and Mogi-Guaçu (São Paulo State), Itamarandiba (Minas Gerais State) and São Jerônimo da Serra (Paraná State) in Brazi

    Detection of somatic mutations of the PIG-A gene in Brazilian patients with paroxysmal nocturnal hemoglobinuria

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    Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal syndrome characterized by intravascular hemolysis mediated by complement, thrombotic events and alterations in hematopoiesis. Basically, the molecular events which underlie the complexity of the syndrome consist of the absence of the glycosylphosphatidylinositol (GPI) anchor as a consequence of somatic mutations in the PIG-A gene, located on the X chromosome. The GPI group is responsible for the attachment of many proteins to the cytoplasmic membrane. Two of them, CD55 and CD59, have a major role in the inhibition of the action of complement on the cellular membrane of blood cells. The absence of GPI biosynthesis can lead to PNH. Since mutations in the PIG-A gene are always present in patients with PNH, the aim of this study was to characterize the mutations in the PIG-A gene in Brazilian patients. The analysis of the PIG-A gene was performed using DNA samples derived from bone marrow and peripheral blood. Conformation-sensitive gel electrophoresis was used for screening the mutation and sequencing methods were used to identify the mutations. Molecular analysis permitted the identification of three point mutations in three patients: one G->A transition in the 5' portion of the second intron, one T->A substitution in the second base of codon 430 (Leu430->stop), and one deletion deltaA in the third base of codon 63. This study represents the first description of mutations in the PIG-A gene in a Brazilian population.76376

    Testing the Meson Cloud Model in Inclusive Meson Production

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    We have applied the Meson Cloud Model to calculate inclusive momentum spectra of pions and kaons produced in high energy proton-proton and proton-nucleus collisions. For the first time these data are used to constrain the cloud cut-off parameters. We show that it is possible to obtain a reasonable description of data, especially the large xFx_F (xF0.2x_F \geq 0.2) part of the spectrum and at the same time describe (partially) the E866 data on dˉuˉ\bar d - \bar u and dˉ/uˉ\bar d / \bar u. We also discuss the relative strength of the πN\pi N and πΔ\pi \Delta vertices. We find out that the corresponding cut-off parameters should be both soft and should not differ by more than 200 MeV from each other. An additional source (other than the meson cloud) of sea antiquark asymmetry, seems to be necessary to completely explain the data. A first extension of the MCM to proton nucleus collisions is discussed.Comment: 14 pages, Latex, 6 ps figures. Submitted to Phys. Rev.

    Benefícios Da Adequação Postural Em Cadeira De Rodas E Fatores Que Interferem Em Sua Utilização: Uma Revisão Sistemática

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    Seating and positioning are an assistive technology resource that aims to improve functional performance in the wheelchair. The aim of this paper was to find in the literature studies that addressed the benefits of seating and positioning in a wheelchair and factors that interfere with the prescription and use of this technology. Articles found that discuss the benefits addressed: the functionality and respiratory function; the pressure ulcer prevention; and user satisfaction and the family with assistive technology. Articles discussing the factors linked to prescription and use of adapting wheelchairs are those that address the environmental factors, components and wheelchair accessories. There are factors involved in the prescription process to achieve its benefits through its use, the prescribed process must have an interdisciplinary and biopsychosocial approach applied individually to each patient.5218119
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