72 research outputs found

    Ocorrência e caracterização de bactérias isoladas de nódulos de amendoinzeiro (Arachis hypogaea L.) em solos paranaenses, Brasil.

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    RESUMO: O objetivo deste trabalho foi avaliar a ocorrência e caracterizar morfofisiologicamente e geneticamente bactérias isoladas de nódulos de amendoinzeiro (Arachis hypogaea L.), em solos paranaenses, Brasil. Em amostras de 36 municípios representativos do estado Paraná foi observada nodulação do amendoim em 84,4%, independente se em áreas cultivadas, ou em florestas. Nos testes de caracterização morfofisiológica de 44 estirpes autenticadas, 75% das estirpes apresentaram taxa de crescimento rápido em meio de cultura com manitol; 25 acidificaram o meio, cinco alcalinizaram e 14 não resultaram em modificação do pH. A capacidade de produzir sideróforos foi observada em 43% das estirpes e 16% foram capazes de solubilizar fosfato de cálcio em meio de cultura. O sequenciamento do gene 16S rRNA mostrou a formação de três principais grupos, correspondentes a três filos: Alfaproteobacteria, Betaproteobacteria e Firmicutes. O gênero com maior ocorrência foi o Bacillus

    Azospirillum brasilense associado a pós de rocha no cultivo de milho orgânico.

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    A inoculação com Azospirillum brasilense pode auxiliar na nutrição nitrogenada em milho, sobretudo em condições de cultivo orgânico em que fontes solúveis de N são evitadas. Além da fonte biológica de N, a associação dessa bactéria pode melhorar o estado nutricional em relação a outros nutrientes, quando as plantas recebem fontes de baixa solubilidade como pós de rocha. O objetivo foi avaliar o efeito da inoculação de A. brasilense em milho sob sistema de produção orgânico, em combinação com pós de basalto de três origens geológicas e fosfato natural fosforita. O experimento foi realizado em duas localidades, Cruz Machado- PR e Irineópolis-SC, no segundo ano de avaliação. O delineamento experimental foi em blocos casualizados, com seis tratamentos de pós de rocha (parcela), em milho inoculado ou não com A. brasilense (subparcela), com quatro repetições. Os tratamentos foram: 3 Mg/ha de pó de basalto I, II e III, 1 Mg/ha de fosfato natural, 3 Mg/ha de pó de basalto I + 1 Mg/ha de fosfato natural e um controle sem rochagem. O milho (variedade crioula Caiano) foi consorciado com feijão de porco na entrelinha. No florescimento, avaliaram-se os teores de N e P nas folhas e a ocorrência de bactérias diazotróficas endofíticas na região da coroa das plantas. Os dados foram submetidos à ANOVA e aplicado o teste Tukey a 5 %. Na área de Cruz Machado, o teor de N nas plantas foi maior nos tratamentos inoculados com A. brasilense, exceto na testemunha sem pó de rocha. Em Irineópolis, não houve efeito dos tratamentos ou subtratamentos. Já o teor de P nas plantas não foi alterado pelos tratamentos ou subtratamentos em Cruz Machado, mas em Irienópolis o milho inoculado apresentou maior teor de P que o não inoculado, e quando inoculadas, as plantas do tratamento com pó de basalto + fosfato natural apresentaram maior teor de P em relação às da testemunha. No geral, nas duas áreas houve maior densidade de bactérias diazotróficas endofíticas nas plantas inoculadas, o que inclui não só A. brasilense, mas também outras bactérias que podem estar contribuindo para a fixação do N2 e promoção do crescimento vegetal. A inoculação com A. brasilense foi eficiente na melhora da nutrição do milho não apenas em relação ao N, mas em alguns casos também em relação ao P, casos em que também houve maior colonização por bactérias diazotróficas no interior da planta.Resumo, 1400-1

    Avaliação da eficiência do inoculante contendo estirpes de Azospirillum brasilense em variedades de cana-de-açúcar.

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    Com aumento do consumo mundial de álcool, as indústrias sucroalcooleiras vêm enfrentando desafios em reduzir insumos e assegurar uma agricultura sustentável. Uma forma de conseguir tais resultados seria a utilização de algumas bactérias diazotróficas e/ou promotoras do crescimento de plantas, como o Azospirillum, contribuindo para o crescimento e a nutrição das plantas e resultando em incremento na produtividade e em diminuição dos custos de produção, principalmente no uso de fertilizantes nitrogenados. O objetivo deste trabalho foi avaliar a eficiência do inoculante Azototal® (Total Biotecnologia- Embrapa), contendo as estirpes AbV5 e AbV6 de Azospirillum brasilense no desenvolvimento da cana-de-açúcar (Saccharum spp.). O experimento foi conduzido em casa de vegetação na Embrapa - Soja, no período de dezembro de 2010 a junho de 2011, em solo de baixo teor de nitrogênio, no crescimento de dez variedades da cana-de-açúcar. Os ensaios foram conduzidos em vasos de 9 Kg, sob condições controladas, sendo compostos pelos tratamentos: (2 mg.Kg?1 de N [T1] controle; 2 mg.Kg?1 de N + Azospirillum brasilense [T2] e 9 mg.Kg?1 de N [T3]). Foram avaliadas dez variedades de cana com oito repetições, totalizando 240 vasos. Foram avaliadas a massa da parte aérea seca e o número de perfilhos das variedades analisadas no período de 90 dias após o brotamento das gemas. Após o corte foi feita a re-inoculação com A. brasilense. Na rebrota os mesmos parâmetros foram analisados. Os resultados demonstram que o A. brasilense, influenciou de maneira significativa o aumento no número de perfilhos e o crescimento da cana-de-açúcar. No primeiro corte, em cinco das dez cultivares houve incremento na produção de massa seca e em duas das variedades houve incremento no número de perfilhos. Já na rebrota, sete variedades tiveram incremento significativo na massa seca e nove em aumento no número de perfilhos. Tais resultados permitem inferir o uso de inoculante contendo Azospirillum como promotor do crescimento da cana-de-açúcar, permitindo também a substituição parcial de fertilizante nitrogenado. Agradecimentos: CNPq pela bolsa fornecida para o desenvolvimento do trabalho e a Embrapa-soja pela disponibilização de recursos e estrutura para a pesquisa.Resumo, 916-1

    Optical properties of aerosol particles over the Amazon rain forest: From background to biomass burning conditions

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    Atmospheric aerosols over the Amazon rainforest are strongly influenced by biomass burning activities in the southern regions of the Amazon Basin between July and October. This implies a complete change of the physical and chemical aerosol properties from the wet season, which is dominated by Primary Biological Aerosol Particles (PBAP) and biogenic secondary organic aerosols. Biomass burning emissions are highly loaded with light-absorbing aerosols, like black and brown carbon (BC and BrC, respectively). The latter one consists of a fraction of organic carbon that is able to absorb visible radiation (Andreae and Gelencs\ue9r, 2006). BrC is a strong absorber at near-UV to UV wavelengths. Therefore, light absorption by this component is wavelength dependent. This wavelength dependency, expressed as the absorption \uc5ngstr\uf6m exponent (AAE), has been used as a parameter to estimate the influence of biomass burning aerosols to total aerosol light absorption. However, the biogenic BrC contribution remains to be studied and could be significant under pristine conditions. The measurements presented here were carried out at the Amazon Tall Tower Observatory (ATTO), located 150 km NE of the city of Manaus, in the Uatum\ue3 Sustainable Development Reserve in Amazonas State, Brazil. The aerosol inlet (60 m high, 2.5 cm diameter) is installed on an 81-m triangular mast. The measurement period, from June to September 2014, includes the wetto- dry transition season (June-July) and part of the dry season (August and beginning of September). The optical properties were measured online by different instruments: 3-wavelengths nephelometer, Multi-Angle Absorption Photometer (MAAP), Single Particle Soot Photometer (SP2) and a 7-wavelength Aethalometer. Additionally, MAAP filter samples were analyzed by the Multi-Wavelength Absorbance Analyzer (MWAA) (Massab\uf2 et al, 2013), as well as levoglucosan analysis was carried out for filters collected between 18-22 August 2014. The average light absorption coefficient at 637 nm was 1.0 \ub1 0.6 Mm-1 and 5.5 \ub1 3.9 Mm-1, during the wet-to-dry transition and the dry season, respectively. Here we concentrate on measurements during 18-22 August 2014 (Figure 1) when a high absorption coefficient was measured at 637 nm, averaging 10 \ub1 3 Mm-1. The AAE calculated from MWAA measurements increased from less than 1.0 to values higher than 1.4, indicating the presence of BrC aerosol particles. This period is characterized by a long-range transport of biomass burning aerosol (confirmed by backward trajectory analysis). Levoglucosan analysis reveals significantly increased concentration but is still relatively low compared to measurements close to the source (Graham et al, 2002). Nevertheless, AAE and levoglucosan concentration show a significant correlation (r\ub2 > 0.9)

    Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

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    Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP) data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA), which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June\u2013September 2014). The mean absorption coefficient (at 637 nm) during this period was 1.8 +/-2.1Mm-1, with a maximum of 15.9Mm-1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption \uc5ngstr\uf6m exponent (\ue5ABS/ retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct \ue5ABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the \ue5ABS retrieved from offline MWAA measurements

    Target for improvement: a cluster randomised trial of public involvement in quality-indicator prioritisation (intervention development and study protocol)

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    <p>Abstract</p> <p>Background</p> <p>Public priorities for improvement often differ from those of clinicians and managers. Public involvement has been proposed as a way to bridge the gap between professional and public clinical care priorities but has not been studied in the context of quality-indicator choice. Our objective is to assess the feasibility and impact of public involvement on quality-indicator choice and agreement with public priorities.</p> <p>Methods</p> <p>We will conduct a cluster randomised controlled trial comparing quality-indicator prioritisation with and without public involvement. In preparation for the trial, we developed a 'menu' of quality indicators, based on a systematic review of existing validated indicator sets. Participants (public representatives, clinicians, and managers) will be recruited from six participating sites. In intervention sites, public representatives will be involved through direct participation (public representatives, clinicians, and managers will deliberate together to agree on quality-indicator choice and use) and consultation (individual public recommendations for improvement will be collected and presented to decision makers). In control sites, only clinicians and managers will take part in the prioritisation process. Data on quality-indicator choice and intended use will be collected. Our primary outcome will compare quality-indicator choice and agreement with public priorities between intervention and control groups. A process evaluation based on direct observation, videorecording, and participants' assessment will be conducted to help explain the study's results. The marginal cost of public involvement will also be assessed.</p> <p>Discussion</p> <p>We identified 801 quality indicators that met our inclusion criteria. An expert panel agreed on a final set of 37 items containing validated quality indicators relevant for chronic disease prevention and management in primary care. We pilot tested our public-involvement intervention with 27 participants (11 public representatives and 16 clinicians and managers) and our study instruments with an additional 21 participants, which demonstrated the feasibility of the intervention and generated important insights and adaptations to engage public representatives more effectively. To our knowledge, this study is the first trial of public involvement in quality-indicator prioritisation, and its results could foster more effective upstream engagement of patients and the public in clinical practice improvement.</p> <p>Trial registration</p> <p><a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2496">NTR2496</a> (Netherlands National Trial Register, <url>http://www.trialregister.nl</url>).</p

    African volcanic emissions influencing atmospheric aerosols over the Amazon rain forest

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    The long-range transport (LRT) of trace gases and aerosol particles plays an important role for the composition of the Amazonian rain forest atmosphere. Sulfate aerosols originate to a substantial extent from LRT sources and play an important role in the Amazonian atmosphere as strongly light-scattering particles and effective cloud condensation nuclei. The transatlantic transport of volcanic sulfur emissions from Africa has been considered as a source of particulate sulfate in the Amazon; however, direct observations have been lacking so far. This study provides observational evidence for the influence of emissions from the Nyamuragira–Nyiragongo volcanoes in Africa on Amazonian aerosol properties and atmospheric composition during September 2014. Comprehensive ground-based and airborne aerosol measurements together with satellite observations are used to investigate the volcanic event. Under the volcanic influence, hourly mean sulfate mass concentrations in the submicron size range reached up to 3.6&thinsp;µg&thinsp;m−3 at the Amazon Tall Tower Observatory, the highest value ever reported in the Amazon region. The substantial sulfate injection increased the aerosol hygroscopicity with κ values up to 0.36, thus altering aerosol–cloud interactions over the rain forest. Airborne measurements and satellite data indicate that the transatlantic transport of volcanogenic aerosols occurred in two major volcanic plumes with a sulfate-enhanced layer between 4 and 5&thinsp;km of altitude. This study demonstrates how African aerosol sources, such as volcanic sulfur emissions, can substantially affect the aerosol cycling and atmospheric processes in Amazonia.</p

    Dental Health and Mortality in People With End-Stage Kidney Disease Treated With Hemodialysis: A Multinational Cohort Study

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    Background Dental disease is more extensive in adults with chronic kidney disease, but whether dental health and behaviors are associated with survival in the setting of hemodialysis is unknown. Study Design Prospective multinational cohort. Setting & Participants 4,205 adults treated with long-term hemodialysis, 2010 to 2012 (Oral Diseases in Hemodialysis [ORAL-D] Study). Predictors Dental health as assessed by a standardized dental examination using World Health Organization guidelines and personal oral care, including edentulousness; decayed, missing, and filled teeth index; teeth brushing and flossing; and dental health consultation. Outcomes All-cause and cardiovascular mortality at 12 months after dental assessment. Measurements Multivariable-adjusted Cox proportional hazards regression models fitted with shared frailty to account for clustering of mortality risk within countries. Results During a mean follow-up of 22.1 months, 942 deaths occurred, including 477 cardiovascular deaths. Edentulousness (adjusted HR, 1.29; 95% CI, 1.10-1.51) and decayed, missing, or filled teeth score ≥ 14 (adjusted HR, 1.70; 95% CI, 1.33-2.17) were associated with early all-cause mortality, while dental flossing, using mouthwash, brushing teeth daily, spending at least 2 minutes on oral hygiene daily, changing a toothbrush at least every 3 months, and visiting a dentist within the past 6 months (adjusted HRs of 0.52 [95% CI, 0.32-0.85], 0.79 [95% CI, 0.64-0.97], 0.76 [95% CI, 0.58-0.99], 0.84 [95% CI, 0.71-0.99], 0.79 [95% CI, 0.65-0.95], and 0.79 [95% CI, 0.65-0.96], respectively) were associated with better survival. Results for cardiovascular mortality were similar. Limitations Convenience sample of clinics. Conclusions In adults treated with hemodialysis, poorer dental health was associated with early death, whereas preventive dental health practices were associated with longer survival
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