132 research outputs found
Dinâmica comparada da substituição das pastagens cultivadas e de sua densidade econômica no arco norte da pecuarização do Brasil.
Avalia comparativamente indicadores de substituição das pastagens cultivadas na Região Amazônica mais sujeitas à reconversão de áreas para pastos (Estados do Acre, Rondônia, Pará e Mato Grosso) com a evolução dos indicadores de sua respectiva densidade econômica, por tamanho de estabelecimento rural. A metodologia utilizada implica a utilização combinada de duas fronteiras, analisadas graficamente: a) uma fronteira da substituição de áreas (de pastagens cultivadas por outros usos do solo) e; b) uma segunda fronteira, que é a variação de relativos da densidade-valor da pecuária, em relação à Área Total Recenseada (ATR). Os resultados não se mostraram uniformes, havendo um ponto em comum para os Estados de Rondônia e Mato Grosso (curva da densidade-valor acima da curva de substituição para os estabelecimentos pequenos a médios), bem como para os Estados do Acre e do Pará, que revelaram uma tendência de a fronteira da densidade-valor se localizar sistematicamente abaixo da fronteira de substituição de áreas. Em termos gerais, pode-se afirmar que, para o espectro relevante da estrutura da produção da pecuária (grandes estabelecimentos), a fronteira da densidade-valor mostrou-se abaixo da fronteira da substituição de áreas. Levando-se em conta os resultados de levantamentos econômicos recentes levados a efeito por alguns autores, que mostram uma rentabilidade bastante favorável das atividades pecuárias na Região Amazônica, os resultados do presente trabalho parecem indicar que os movimentos alocativos mais que proporcionais da área das pastagens cultivadas em relação à densidade-valor, verificados até meados da década de 90 apresentam objetivos múltiplos, que vão além da produção pecuária em si mesma (abertura de áreas para consolidação da própria atividade pecuária, conversão para lavouras, consolidação de ativos patrimoniais, envolvendo a expulsão de populações nativas, etc
Agronomic Evaluation of Forage Grasses under Mature Rubber Plantation
The agronomic performance of seven forage grasses, under a mature rubber plantation, was assessed in a cutting trial carried out at Porto Velho, Rondônia. During the rainy season, the higher dry matter yields were obtained with B. brizantha, P. atratum BRA-9610 and B. humidicola. During the dry season, the grasses more productive were B. brizantha and P. atratum BRA-9610. In both seasons, magnesium and potassium contents did not vary among grasses. During the rainy season, the higher nitrogen and phosphorus contents were obtained with P. regnelli BRA-0159 and, P. guenoarum BRA-3824 and B. humidicola, respectively, while P. atratum BRA-9610 and B. humidicola provided higher contents of calcium. During the dry season, P. regnelli BRA-0159 showed the highest nitrogen content, while B. humidicola and B. brizantha gave the highest phosphorus and calcium contents. In order to obtain greater forage yields with better quality, the grasses more promising for pasture establishment in a silvipastoral systems were B. brizantha, B. humidicola and P. atratum BRA-9610
Structure of the TPR Domain of AIP: Lack of Client Protein Interaction with the C-Terminal alpha-7 Helix of the TPR Domain of AIP Is Sufficient for Pituitary Adenoma Predisposition
PMCID: PMC3534021This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
A Novel Mutation in the Upstream Open Reading Frame of the CDKN1B Gene Causes a MEN4 Phenotype
PubMed ID: 23555276This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Cup Blocks the Precocious Activation of the Orb Autoregulatory Loop
Translational regulation of localized mRNAs is essential for patterning and axes determination in many organisms. In the Drosophila ovary, the germline-specific Orb protein mediates the translational activation of a variety of mRNAs localized in the oocyte. One of the Orb target mRNAs is orb itself, and this autoregulatory activity ensures that Orb proteins specifically accumulate in the developing oocyte. Orb is an RNA-binding protein and is a member of the cytoplasmic polyadenylation element binding (CPEB) protein family. We report here that Cup forms a complex in vivo with Orb. We also show that cup negatively regulates orb and is required to block the precocious activation of the orb positive autoregulatory loop. In cup mutant ovaries, high levels of Orb accumulate in the nurse cells, leading to what appears to be a failure in oocyte specification as a number of oocyte markers inappropriately accumulate in nurse cells. In addition, while orb mRNA is mislocalized and destabilized, a longer poly(A) tail is maintained than in wild type ovaries. Analysis of Orb phosphoisoforms reveals that loss of cup leads to the accumulation of hyperphosphorylated Orb, suggesting that an important function of cup in orb-dependent mRNA localization pathways is to impede Orb activation
Dynamics of Socioeconomic Risk Factors for Neglected Tropical Diseases and Malaria in an Armed Conflict
Armed conflict and war and infectious diseases are globally among the leading causes of human suffering and premature death. Moreover, they are closely interlinked, as an adverse public health situation may spur violent conflict, and violent conflict may favor the spread of infectious diseases. The consequences of this vicious cycle are increasingly borne by civilians, often as a hidden and hence neglected burden. We analyzed household data that were collected before and after an armed conflict in a rural part of western Côte d'Ivoire, and investigated the dynamics of socioeconomic risk factors for neglected tropical diseases (NTDs) and malaria. We identified a worsening of the sanitation infrastructure, decreasing use of protective measures against mosquito bites, and increasing difficulties to reach public health care infrastructure. In contrast, household crowding, the availability of soap, and the accessibility of comparatively simple means of health care provision (e.g., traditional healers and community health workers) seemed to be more stable. Knowledge about such dynamics may help to increase crisis-proofness of critical infrastructure and public health systems, and hence mitigate human suffering due to armed conflict and war
Microbiological characteristics of clinical isolates of Cryptococcus spp. in Bahia, Brazil: molecular types and antifungal susceptibilities
To determine the profiles of susceptibility to antifungal and the genotypes of clinical isolates of Cryptococcus in Bahia, Brazil, 62 isolates were collected from cases of meningitis in the period from 2006 to 2010. Their susceptibilities to fluconazole, itraconazole, amphotericin B and 5-flucytosine were determined by the broth microdilution technique described by the Clinical and Laboratory Standards Institute and genotyping of the URA5 gene was accomplished by restriction fragment length polymorphism. C. neoformans accounted for 79% of the identified yeast and C. gattii represented the remaining 21%. Evaluation of the genotypes determined that 100% of the C. gattii isolates belong to the VGII genotype, and 98% of the C. neoformans isolates belong to the VNI genotype. Determination of susceptibility revealed isolates resistant to fluconazole (4.8%), 5-flucytosine (1.6%) and amphotericin B (3.2%); the stratification of sensitivity results for each species showed significant differences in susceptibility to azoles. This study is the first to describe the susceptibility profiles of molecular and clinical isolates of Cryptococcus in Bahia, Brazil. The high percentage of C. gattii isolates belonging to the VGII genotype and its lower susceptibility to antifungal agents highlight the importance of knowing which species are involved in cryptococcal infections in northeastern Brazil
Endothelial progenitor cells and integrins: adhesive needs
In the last decade there have been multiple studies concerning the contribution of endothelial progenitor cells (EPCs) to new vessel formation in different physiological and pathological settings. The process by which EPCs contribute to new vessel formation in adults is termed postnatal vasculogenesis and occurs via four inter-related steps. They must respond to chemoattractant signals and mobilize from the bone marrow to the peripheral blood; home in on sites of new vessel formation; invade and migrate at the same sites; and differentiate into mature endothelial cells (ECs) and/or regulate pre-existing ECs via paracrine or juxtacrine signals. During these four steps, EPCs interact with different physiological compartments, namely bone marrow, peripheral blood, blood vessels and homing tissues. The success of each step depends on the ability of EPCs to interact, adapt and respond to multiple molecular cues. The present review summarizes the interactions between integrins expressed by EPCs and their ligands: extracellular matrix components and cell surface proteins present at sites of postnatal vasculogenesis. The data summarized here indicate that integrins represent a major molecular determinant of EPC function, with different integrin subunits regulating different steps of EPC biology. Specifically, integrin α4β1 is a key regulator of EPC retention and/or mobilization from the bone marrow, while integrins α5β1, α6β1, αvβ3 and αvβ5 are major determinants of EPC homing, invasion, differentiation and paracrine factor production. β2 integrins are the major regulators of EPC transendothelial migration. The relevance of integrins in EPC biology is also demonstrated by many studies that use extracellular matrix-based scaffolds as a clinical tool to improve the vasculogenic functions of EPCs. We propose that targeted and tissue-specific manipulation of EPC integrin-mediated interactions may be crucial to further improve the usage of this cell population as a relevant clinical agent
Desenvolvimento de filmes poliméricos ultrafinos e reticulados para aplicações em sensores
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