269 research outputs found

    Increased Litterfall in Tropical Forests Boosts the Transfer of Soil CO2 to the Atmosphere

    Get PDF
    Aboveground litter production in forests is likely to increase as a consequence of elevated atmospheric carbon dioxide (CO2) concentrations, rising temperatures, and shifting rainfall patterns. As litterfall represents a major flux of carbon from vegetation to soil, changes in litter inputs are likely to have wide-reaching consequences for soil carbon dynamics. Such disturbances to the carbon balance may be particularly important in the tropics because tropical forests store almost 30% of the global soil carbon, making them a critical component of the global carbon cycle; nevertheless, the effects of increasing aboveground litter production on belowground carbon dynamics are poorly understood. We used long-term, large-scale monthly litter removal and addition treatments in a lowland tropical forest to assess the consequences of increased litterfall on belowground CO2 production. Over the second to the fifth year of treatments, litter addition increased soil respiration more than litter removal decreased it; soil respiration was on average 20% lower in the litter removal and 43% higher in the litter addition treatment compared to the controls but litter addition did not change microbial biomass. We predicted a 9% increase in soil respiration in the litter addition plots, based on the 20% decrease in the litter removal plots and an 11% reduction due to lower fine root biomass in the litter addition plots. The 43% measured increase in soil respiration was therefore 34% higher than predicted and it is possible that this ‘extra’ CO2 was a result of priming effects, i.e. stimulation of the decomposition of older soil organic matter by the addition of fresh organic matter. Our results show that increases in aboveground litter production as a result of global change have the potential to cause considerable losses of soil carbon to the atmosphere in tropical forests

    Intimate partner violence against women in an economically vulnerable urban area, Central-West Brazil

    Get PDF
    OBJETIVO: Estimar a prevalência de tipos de violência e de comportamentos de controle praticados por parceiros íntimos contra mulheres residentes em área economicamente vulnerável. MÉTODOS: Conduziu-se estudo transversal com 278 mulheres de 15 a 49 anos que tiveram parceiros íntimos alguma vez na vida, residentes em uma área metropolitana de Brasília, DF, em 2007. Utilizou-se processo de amostragem aleatória sistemática. O instrumento de pesquisa constou de um questionário com 58 perguntas desenvolvido pela Organização Mundial de Saúde. Foram analisadas as prevalências de violência física, psicológica e sexual. As variáveis independentes consideradas foram características sociodemográficas da mulher, de contexto familiar e comunitário bem como as sociodemográfi cas do parceiro, de comportamento (freqüência do uso de bebidas ou drogas ilícitas e relacionamento extraconjugal). RESULTADOS: A prevalência de violência psicológica foi a mais alta: 80,2% (n=223) das mulheres entrevistadas relataram pelo menos um ato no decorrer da vida e 50% (n=139) nos últimos 12 meses. A prevalência de violência física ao longo da vida foi (58,6%) e nos últimos 12 meses (32%), enquanto a prevalência de mulheres que sofreram violência sexual foi de 28,8% e 15,5%, respectivamente. CONCLUSÕES: As altas prevalências das violências mostram a magnitude da vulnerabilidade e das agressões praticadas contra mulheres nas relações com parceiros íntimos.OBJECTIVE: To estimate the prevalence of gender-based controlling behavior and types of violence committed by intimate partners against women living in an economically vulnerable area. METHODS: A cross-sectional study was performed with 278 women aged between 15 and 49 years, who had had at least one male intimate partner in their lives and lived in a metropolitan area of the city of Brasília, Central-West Brazil, in 2007. Systematic random sampling process was used. The research instrument consisted of a questionnaire with 58 questions, developed by the World Health Organization. Prevalences of physical, psychological and sexual violence were analyzed. Independent variables considered were women’s sociodemographic, family and community context characteristics, in addition to their partners’ sociodemographic and behavior characteristics (frequency of alcohol or illicit drug use and extra-marital relationship). RESULTS: The highest prevalence was that of psychological violence: 80.2% (n=223) of the women interviewed reported at least one act throughout their lives and 50% (n=139) in the last 12 months. Prevalence of physical violence was 58.6% throughout life and 32% in the last 12 months, whereas those of sexual violence were 28.8% and 15.5%, respectively. CONCLUSIONS: High prevalences of violence show the magnitude of vulnerability and aggressions committed against women in relationships with intimate partners

    Phytochemicals as antibiotic alternatives to promote growth and enhance host health

    Get PDF
    There are heightened concerns globally on emerging drug-resistant superbugs and the lack of new antibiotics for treating human and animal diseases. For the agricultural industry, there is an urgent need to develop strategies to replace antibiotics for food-producing animals, especially poultry and livestock. The 2nd International Symposium on Alternatives to Antibiotics was held at the World Organization for Animal Health in Paris, France, December 12-15, 2016 to discuss recent scientific developments on strategic antibiotic-free management plans, to evaluate regional differences in policies regarding the reduction of antibiotics in animal agriculture and to develop antibiotic alternatives to combat the global increase in antibiotic resistance. More than 270 participants from academia, government research institutions, regulatory agencies, and private animal industries from >25 different countries came together to discuss recent research and promising novel technologies that could provide alternatives to antibiotics for use in animal health and production; assess challenges associated with their commercialization; and devise actionable strategies to facilitate the development of alternatives to antibiotic growth promoters (AGPs) without hampering animal production. The 3-day meeting consisted of four scientific sessions including vaccines, microbial products, phytochemicals, immune-related products, and innovative drugs, chemicals and enzymes, followed by the last session on regulation and funding. Each session was followed by an expert panel discussion that included industry representatives and session speakers. The session on phytochemicals included talks describing recent research achievements, with examples of successful agricultural use of various phytochemicals as antibiotic alternatives and their mode of action in major agricultural animals (poultry, swine and ruminants). Scientists from industry and academia and government research institutes shared their experience in developing and applying potential antibiotic-alternative phytochemicals commercially to reduce AGPs and to develop a sustainable animal production system in the absence of antibiotics.Fil: Lillehoj, Hyun. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Liu, Yanhong. University of California; Estados UnidosFil: Calsamiglia, Sergio. Universitat Autònoma de Barcelona; EspañaFil: Fernandez Miyakawa, Mariano Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Chi, Fang. Amlan International; Estados UnidosFil: Cravens, Ron L.. Amlan International; Estados UnidosFil: Oh, Sungtaek. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Gay, Cyril G.. United States Department of Agriculture. Agricultural Research Service; Argentin

    Participation, knowledge production, and evaluative research: participation by different actors in a mental health study

    Get PDF
    This article reflects on the interrelations between participation, knowledge production, and public policy evaluation in light of issues from our own experience with evaluative research on a municipal network of Psychosocial Care Centers (CAPS) in Brazil. The article discusses the coordination of the complex process and the potentials and limits of partnerships for conducting qualitative evaluative studies in mental health with participation by different social actors. The authors conclude that qualitative evaluative research aligned with the perspective of including different points of view representing various segments is the best approach for understanding the numerous spin-offs from the implementation of services linked to the Brazilian psychiatric reform movement, given the inherent specificities of the mental health field.No presente texto apresentamos considerações sobre pesquisa avaliativa qualitativa e participativa com base em investigação desta natureza realizada junto a uma rede municipal de Centros de Atenção Psicossocial (CAPS) ligados ao Sistema Único de Saúde (SUS). A coordenação do complexo processo, bem como as potencialidades e limites do estabelecimento de parcerias para a realização de trabalhos de investigação avaliativa qualitativa em saúde mental, com a inclusão de diferentes atores sociais, são aqui discutidas. Concluímos que a pesquisa avaliativa qualitativa aliada à perspectiva de inclusão de distintos pontos de vista dos vários segmentos envolvidos é a que melhor se adequa à compreensão dos muitos desdobramentos oriundos da implementação de serviços ligados ao movimento de reforma psiquiátrica brasileira, dado as especificidades inerentes ao campo da saúde mental.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP)Universidade Estadual de Campinas FCMUNIFESPSciEL

    Identification of a tyrosine residue responsible for N-acetylimidazole-induced increase of activity of ecto-nucleoside triphosphate diphosphohydrolase 3

    Get PDF
    Chemical modification in combination with site-directed mutagenesis was used to identify a tyrosine residue responsible for the increase in ecto-nucleoside triphosphate diphosphohydrolase 3 (NTPDase3) nucleotidase activity after acetylation with a tyrosine-selective reagent, N-acetylimidazole. The NTPDase3 ATPase activity is increased more than the ADPase activity by this reagent. Several fairly well conserved tyrosine residues (252, 255, and 262) that are located in or very near apyrase conserved region 4a (ACR4a) were mutated. These mutants were all active, but mutation of tyrosine 252 to either alanine or phenylalanine eliminated the activity increase observed after N-acetylimidazole treatment of the wild-type enzyme. This suggests that the acetylation of tyrosine 252 is responsible for the increased activity. Stabilization of quaternary structure has resulted in increased enzyme activities for the NTPDases. However, mutation of these three tyrosine residues did not result in global changes of tertiary or quaternary structure, as measured by Cibacron blue binding, chemical cross linking, and native gel electrophoretic analysis. Nevertheless, disruption of the oligomeric structure with the detergent Triton X-100 abolished the increase in activity induced by this reagent. In addition, mutations that abolished the N-acetylimidazole effect also attenuated the increases of enzyme activity observed after lectin and chemical cross-linking treatments, which were previously attributed to stabilization of the quaternary structure. Thus, we speculate that the acetylation of tyrosine 252 might induce a subtle conformational change in NTPDase3, resulting in the observed increase in activity

    Cloning and characterization of the ecto-nucleotidase NTPDase3 from rat brain: Predicted secondary structure and relation to other members of the E-NTPDase family and actin

    Get PDF
    The protein family of ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDase family) contains multiple members that hydrolyze nucleoside 5’-triphosphates and nucleoside 5’-diphosphates with varying preference for the individual type of nucleotide. We report the cloning and functional expression of rat NTPDase3. The rat brain-derived cDNA has an open reading frame of 1590 bp encoding 529 amino acid residues, a calculated molecular mass of 59.1 kDa and predicted N- and C-terminal hydrophobic sequences. It shares 94.3% and 81.7% amino acid identity with the mouse and human NTPDase3, respectively, and is more closely related to cell surface-located than to the intracellularly located members of the enzyme family. The NTPDase3 gene is allocated to chromosome 8q32 and organized into 11 exons. Rat NTPDase3 expressed in CHO cells hydrolyzed both nucleoside triphosphates and nucleoside diphosphates with hydrolysis ratios of ATP:ADP of 5:1 and UTP:UDP of 8:1. After addition of ATP, ADP is formed as an intermediate product that is further hydrolyzed to AMP. The enzyme is preferentially activated by Ca2+ over Mg2+ and reveals an alkaline pH optimum. Immunocytochemistry confirmed expression of heterologously expressed NTPDase3 to the surface of CHO cells. PC12 cells express endogenous surface-located NTPDase3. An immunoblot analysis detects NTPDase3 in all rat brain regions investigated. An alignment of the secondary structure domains of actin conserved within the actin/HSP70/sugar kinase superfamily to those of all members of the NTPDase family reveals apparent similarity. It infers that NTPDases share the two-domain structure with members of this enzyme superfamily
    corecore