559 research outputs found

    DISTRIBUIÇÃO LONGITUDINAL DE PLANTAS E RESISTÊNCIA MECÂNICA DO SOLO À PENETRAÇÃO EM SEMEADURA DE FEIJÃO

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    Seeders-fertilizers can present problems of direct seeding performance, which are related to soils with high clay contents. Mapping the spatial variability of soil attributes makes it possible to rationalize agricultural management and promote sustainable agriculture. The objective of this work was to evaluate the spatial variability of the longitudinal distribution of plants, and the mechanical resistance of the soil to penetration (RMSP) in sowing of beans grown under no-tillage. A sampling mesh with 112 points spaced 25 m was used, where the plant stand, the uniformity of spacing between seedlings and the RMSP were determined. Most of the area showed low levels of acceptable spacing (45 and 55%), and consequently high levels of double spacing (15 and 25%) and flaws (15 to 35%), showing that the arrangement of plants in the experimental area did not is adequate. The plant stand showed good uniformity throughout the area, with a predominance of 9 to 11 plants m-1. The Mechanical Resistance of Soil to Penetration in the layers of 0.00 - 0.10, 0.10 - 0.20, 0.20 - 0.30, 0.30 - 0.40 m are within the tolerable limits, not restricting plant development.As semeadoras-adubadoras podem apresentar problemas de desempenho de semeadura direta, sendo estes relacionados a solos com altos teores de argila. Com o mapeamento da variabilidade espacial de atributos do solo se torna possível racionalizar o manejo agrícola e promover uma agricultura sustentável. O objetivo deste trabalho foi avaliar a variabilidade espacial da distribuição longitudinal de plantas, e a resistência mecânica do solo à penetração (RMSP) em semeadura de feijão cultivado em semeadura direta. Foi utilizada uma malha amostral com 112 pontos espaçados em 25 m, onde determinou-se o estande de plantas, a uniformidade de espaçamento entre plântulas e a RMSP. A Maior parte da área mostrou baixos níveis de espaçamentos aceitáveis (45 e 55%), e consequentemente altos níveis de espaçamentos duplos (15 e 25%) e falhos (15 a 35%), mostrando que o arranjo de plantas na área experimental não está adequado. O estande de plantas apresentou boa uniformidade ao longo da área, com predomínio da faixa de 9 a 11 plantas m-1. A Resistência Mecânica do Solo à Penetração nas camadas de 0,00 - 0,10, 0,10 - 0,20, 0,20 - 0,30, 0,30 - 0,40 m estão dentro dos limites toleráveis, não restringindo o desenvolvimento de plantas

    Sensibility of coffee plants micorrized to herbicides

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    Objetivou-se com esse trabalho avaliar o efeito de herbicidas aplicados em pós-emergência em plantas de café arábica inoculadas com fungos micorrízicos arbusculares. O experimento foi conduzido em esquema fatorial 2 x 6, sendo mudas de café arábica cultivar Catuaí IAC 99 inoculadas e não inoculadas com fungos micorrízicos arbusculares, e cinco herbicidas (chlorimuron-ethyl, oxyfluorfen, fluazifop-p-butil, fomesafen, [fluazifop-p-butil+fomesafen]) e uma testemunha, com quatro repetições. As mudas inoculadas com fungos micorrízicos arbusculares (Rhizophagus clarus e Gigaspora margarita) e produzidas em sacolas plásticas contendo solo e esterco (3:1) foram transplantadas para vasos de 20 dm3 de solo, no estádio de cinco pares de folhas. No estádio de sete pares de folhas foram submetidas a aplicação dos herbicidas. Após a aplicação do herbicida foram mensuradas: porcentagem de intoxicação, altura, área foliar, volume radicular, matéria seca das folhas e raízes, teor nutricional da folha e colonização radicular. Observou-se que a aplicação de chlorimuron-ethyl, oxyfluorfen e [fluazifop-p-butil+fomesafen] resultaram em menor incremento das variáveis e maior intoxicação. O fluazifop-p-butil apresentou maior seletividade para as plantas de café. As plantas inoculadas obtiveram maior colonização radicular de fungos micorrízicos que as não inoculadas. Apenas o fluazifop-p-butil não causou interferência na colonização, sendo que as plantas inoculadas mostraram menor intoxicação que as não inoculadas. Considerando todos os parâmetros avaliados conclui-se que as plantas de café arábica cultivar Catuaí Vermelho IAC 99 inoculadas com fungos micorrízicos arbusculares apresentaram maior tolerância ao fluazifop-p-butil. Da mesma forma, conclui-se também que plantas de café quando inoculadas com FMAs apresentaram-se mais tolerantes aos efeitos negativos dos herbicidas chlorimuron-ethyl, fomesafen, oxyfluorfen e [fluazifop-p-butil+fomesafen].  The objective of this work was to evaluate the effects of herbicides applied in post-emergence of Arabic coffee plants inoculated and non-inoculated with arbuscular mycorrhizal fungi. The experiment was conducted in a factorial arrangement 2 x 6, being seedlings of Arabic coffee (Catuaí IAC 99 cv) inoculated and non-inoculated with mycorrhizal fungi (Factor 1), and five herbicides (chlorimuron-ethyl, oxyfluorfen, fluazifop-p-butil, fomesafen, [fluazifop-p-butil + fomesafen]) and a control treatment (Factor 2), with four replications. The seedlings inoculated with mycorrhizal fungi (Rhizophagus clarus and Gigaspora margarita) were produced in polyethylene bags and transplanted to 20 dm3 pots when it was in five pairs leaves stage. In seven pairs leaves stage the plants were submitted to the herbicide applications. After 45 days were measured: percentage of intoxication, height, leaf area, root volume, leaves and roots dry matter, leaf nutrient content and root colonization. Noted that chlorimuron-ethyl, oxyfluorfen and [fluazifop-p-butil+fomesafen] resulting in less increment of variables and higher phytotoxicity. The fluazifop-p-butil showed greater selectivity to coffee plants. The inoculated plants obtained higher root colonization than non-inoculated. Considering all parameters, it is concluded that the Arabica coffee cultivar Catuaí Vermelho IAC 99 inoculated with mycorrhizal fungi showed higher tolerance to fluazifop-p-butil. Similarly, also concludes that coffee plants inoculated with FMAs had become more tolerant to the adverse effects of chlorimuron-ethyl, fomesafen, oxyfluorfen and [fluazifop-p-butil + fomesafen]

    Perdas na colheita mecanizada direta do feijoeiro comum / Losses on the mechanized direct harvest of common bean

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    O feijoeiro é uma cultura de grande importância para a sociedade brasileira. Dentre as etapas de produção, a colheita é uma das mais importantes. Objetivou-se com esse trabalho avaliar as perdas na colheita mecanizada direta do feijoeiro, sob diferentes velocidades de deslocamento e regulagens da colhedora. O experimento foi realizado na Fazenda Bom Sucesso, localizada no município de São Luiz do Norte - GO, situado na região do Vale São Patrício. O delineamento experimental utilizado foi o DIC, em esquema fatorial 3x2, sendo os tratamentos compostos por três velocidades de deslocamento (3, 4 e 5 km h-1) e duas regulagens dos sistemas da colhedora, com 6 repetições por tratamento. Foram avaliadas as perdas por altura de corte (PAC), perdas na plataforma (PP), perdas internas (PI), perdas total da máquina (PTM), e perdas total colheita (PTC). Os resultados foram submetidos à análise de variância e ao controle estatístico de processo. As diferentes velocidades de colheita e regulagens avaliadas não influenciaram significativamente nas perdas, embora tenha se verificado nas cartas de controle uma alta variabilidade dos dados, principalmente para as velocidades de 4 e 5 km h-1 na regulagem 1. Os maiores níveis de perdas foram observados nos mecanismos internos da colhedora, que representaram 46 a 60% da perda total da máquina. Sob a ótica do controle estatístico de processo, a velocidade de 3 km h-1 associada a regulagem 2 proporcionou menor variabilidade dos dados

    Transcriptional profiles of the human pathogenic fungus paracoccidioides brasiliensis in mycelium and yeast cells

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    This work was supported by MCT, CNPq, CAPES, FUB, UFG, and FUNDECT-MS. PbGenome Network: Alda Maria T. Ferreira, Alessandra Dantas, Alessandra J. Baptista, Alexandre M. Bailão, Ana Lídia Bonato, André C. Amaral, Bruno S. Daher, Camila M. Silva, Christiane S. Costa, Clayton L. Borges, Cléber O. Soares, Cristina M. Junta, Daniel A. S. Anjos, Edans F. O. Sandes, Eduardo A. Donadi, Elza T. Sakamoto-Hojo, Flábio R. Araújo, Flávia C. Albuquerque, Gina C. Oliveira, João Ricardo M. Almeida, Juliana C. Oliveira, Kláudia G. Jorge, Larissa Fernandes, Lorena S. Derengowski, Luís Artur M. Bataus, Marcus A. M. Araújo, Marcus K. Inoue, Marlene T. De-Souza, Mauro F. Almeida, Nádia S. Parachin, Nadya S. Castro, Odair P. Martins, Patrícia L. N. Costa, Paula Sandrin-Garcia, Renata B. A. Soares, Stephano S. Mello, and Viviane C. B. ReisParacoccidioides brasiliensis is the causative agent of paracoccidioidomycosis, a disease that affects 10 million individuals in Latin America. This report depicts the results of the analysis of 6,022 assembled groups from mycelium and yeast phase expressed sequence tags, covering about 80% of the estimated genome of this dimorphic, thermo-regulated fungus. The data provide a comprehensive view of the fungal metabolism, including overexpressed transcripts, stage-specific genes, and also those that are up- or down-regulated as assessed by in silico electronic subtraction and cDNA microarrays. Also, a significant differential expression pattern in mycelium and yeast cells was detected, which was confirmed by Northern blot analysis, providing insights into differential metabolic adaptations. The overall transcriptome analysis provided information about sequences related to the cell cycle, stress response, drug resistance, and signal transduction pathways of the pathogen. Novel P. brasiliensis genes have been identified, probably corresponding to proteins that should be addressed as virulence factor candidates and potential new drug targets

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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    Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

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    Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

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    Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications
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