3,704 research outputs found

    Perfil das unidades de produção familiares na comunidade de N. S. do Rosário - Parintins/AM.

    Get PDF
    O objetivo deste trabalho foi realizar a caracterização e a sistematização das práticas agrícolas sustentáveis desenvolvidas pelos agricultores familiares de comunidade tradicionais da Amazônia, devido o baixo interesse sobre estudos para a sistematização e caracterização de agriculturas com base ecológica nas comunidades rurais de terra firme no município foi escolhida uma comunidade com estas características

    Seismic vulnerability assessment of historical urban centres: The case study of campi alto di norcia, Italy

    Get PDF
    Seismic damage assessment is a valuable opportunity to evaluate the accuracy of vulnerability and risk methodologies applied to historic masonry buildings, giving the possibility of enhancing and optimizing mitigation and retrofit strategies. Vulnerability index methodologies are flexible and powerful tools for the seismic assessment at urban scale, able to provide a first screening of the critical issues present in masonry structural aggregates. The different structural features of the buildings, directly and indirectly influencing their structural behaviour, are measured through different weights and scores finally achieving a vulnerability indicator. In the present paper, four different vulnerability index methodologies are applied to the medieval city of Campi Alto di Norcia in Valnerina, Umbria, recently stroke by the 2016 Central Italy earthquakes. The accuracy of the adopted Iv methods is assessed based on the real damages' analysis performed in the surrounding area, comparing results achieved from the application of considered methodologies to direct in-situ observations. Data collected during the 2016 post-earthquake damage surveys and usability assessment, together with the external visual inspections carried out and with the information coming from retrofitting design interventions performed between 1979 and 1997, are used

    Temperature dependence of the electron spin g factor in GaAs

    Get PDF
    The temperature dependence of the electron spin gg factor in GaAs is investigated experimentally and theoretically. Experimentally, the gg factor was measured using time-resolved Faraday rotation due to Larmor precession of electron spins in the temperature range between 4.5 K and 190 K. The experiment shows an almost linear increase of the gg value with the temperature. This result is in good agreement with other measurements based on photoluminescence quantum beats and time-resolved Kerr rotation up to room temperature. The experimental data are described theoretically taking into account a diminishing fundamental energy gap in GaAs due to lattice thermal dilatation and nonparabolicity of the conduction band calculated using a five-level kp model. At higher temperatures electrons populate higher Landau levels and the average gg factor is obtained from a summation over many levels. A very good description of the experimental data is obtained indicating that the observed increase of the spin gg factor with the temperature is predominantly due to band's nonparabolicity.Comment: 6 pages 4 figure

    Visual adaptation reveals multichannel coding for numerosity

    Get PDF
    Visual numerosity is represented automatically and rapidly, but much remains unknown about the computations underlying this perceptual experience. For example, it is unclear whether numerosity is represented with an opponent channel or multichannel coding system. Within an opponent channel system, all numerical values are represented via the relative activity of two pools of neurons (i.e., one pool with a preference for small numerical values and one pool with a preference for large numerical values). However, within a multichannel coding system, all numerical values are represented directly, with separate pools of neurons for each (discriminable) numerical value. Using an adaptation paradigm, we assessed whether the visual perception of number is better characterized by an opponent channel or multichannel system. Critically, these systems make distinct predictions regarding the pattern of aftereffects exhibited when an observer is adapted to an intermediate numerical value. Opponent channel coding predicts no aftereffects because both pools of neurons adapt equally. By contrast, multichannel coding predicts repulsive aftereffects, wherein numerical values smaller than the adapter are underestimated and those larger than the adapter are overestimated. Consistent with multichannel coding, visual adaptation to an intermediate value (50 dots) yielded repulsive aftereffects, such that participants underestimated stimuli ranging from 10–50 dots, but overestimated stimuli ranging from 50–250 dots. These findings provide novel evidence that the visual perception of number is supported by a multichannel, not opponent channel, coding system, and raise important questions regarding the contributions of different cortical regions, such as the ventral and lateral intraparietal areas, to the representation of number

    Structural changes in intestinal enteroendocrine cells after ileal interposition in normal rats

    Get PDF
    INTRODUCTION: No therapeutic approach has significantly impacted the progression of diabetes. As early improvement of glicaemic control is observed after bariatric surgeries, there is currently a search for surgical procedures that can promote euglycemia also in non-obese patients. Glicaemic control can be achieved by increasing the blood concentration of GLP-1, a hormone produced by L cells that are more densely concentrated in the terminal ileum. The interposition of ileal segment to a more anterior region (proximal jejunum) can promote a greater stimulation of the L cells by poorly digested food, increasing the production of GLP-1 and reflecting on glicaemic control.
AIMS: To investigate long-term histological modifications of intestinal mucosa of rats submitted to interposition of ileum segment to a proximal region (jejunum).
METHODS: Forty 8-week old male Wistar-EPM1 rats (Rattus norvegicus albinus) were randomly distributed into 3 groups: the Interposition Group (IG) was subjected to ileal interposition, the Sham Group (SG) was subjected to sham operations, and the Control Group (CG) was not subjected to surgery. All animals were followed until the 60th postoperative day (8 postoperative week) when they were euthanized. Segments of jejunum and ileum from all groups were collected and analyzed by optical microscopy and immunohistochemistry.
RESULTS: No structural nor histological changes in intestinal L cells in the interposed intestinal segment and other intestinal segments were noted after ileal interposition surgery. 
CONCLUSION: As L cells endocrine characteristics were likely maintained, the use of metabolic surgical techniques for the treatment of metabolic diseases, especially diabetes, seems to be justified

    Implantação de ervais.

    Get PDF
    Distribuição e propagacao da erva-mate, area de distribuicao natural, clima, solos; Propagacao da erva-mate: selecao de arvores matrizes, colheita de sementes, separacao de sementes, estratificacao de sementes, conservacao de sementes, construcao do viveiro, construcao das sementeiras, semeadura, germinacao, cuidados com as plântulas e repicagem, recipientes, propagacao vegetativa, doenças de sementeira e viveiro, adubarão de mudas em viveiro, justificação das mudas para o plantio; Preparo e conservacao do solo; Espaçamentos: pequenos produtores, médios e grandes produtores; Plantio: época de plantio e proteção das mudas, adubação de plantio; Replantio; Associação com outras culturas no ano do plantio; Poda de formação.bitstream/CNPF-2009-09/15737/1/circ-tec41.pd

    Caracterização de agroecossistemas baseados na cana de açúcar na comunidade do Caburi, Parintins - Amazonas.

    Get PDF
    O objetivo deste estudo foi realizar levantamento e sistematizar experiências de agriculturas de base ecológica na comunidade do Caburi, Parintins-AM. Foram selecionadas famílias de forma aleatória cuja amostra fosse representativa da comunidade
    corecore