Aperfeiçoamento do método para avaliação da deriva de inseticida granulado aplicado por via aérea em lavouras de arroz irrigado.

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A seleção de critérios no zoneamento agroecológico: proposta metodológica.

A seleção de critérios espaciais para um trabalho de zoneamento agroecológico envolve critérios de aptidão, biodiversidade, socioeconomia, recursos hídricos, legais, ambientais, políticas etc. É necessário identificar a questão-chave e traçar diretrizes do zoneamento que representem as orientações do setor. Essas diretrizes são econômicas, estratégicas, empresariais, sociais, técnicas e políticas, obtidas em negociação com representantes de diferentes setores da sociedade e, ao fim, ponderar os diversos critérios segundo a importância de cada um, no contexto em análise. Este trabalho tem por objetivo apresentar uma metodologia de identificação coletiva desses critérios com o aporte de recursos de sistemas de suporte à decisão espacial e de planejamento estratégico territorial. A metodologia apresenta as seguintes etapas: diagnóstico estratégico, identificação de critérios determinantes (não ponderáveis), identificação dos critérios a serem ponderados e uma proposta de fluxo de procedimentos para a seleção de critérios espaciais. Visa subsidiar a formulação de políticas públicas de ordenamento territorial do setor rural. O resultado é composto de um conjunto de procedimentos e de uma lista de perguntas-chave para compor os diagnósticos e selecionar os critérios espaciais que podem ser aplicados em trabalhos de planejamento territorial adicionado a visão estratégica

Endophytic Bacillus strains enhance pearl millet growth and nutrient uptake under low-P.

tBacterial endophytes are considered to have a beneficial effect on host plants, improv-ing their growth by different mechanisms. The objective of this study was to investigatethe capacity of four endophytic Bacillus strains to solubilize iron phosphate (Fe-P), pro-duce siderophores and indole-acetic acid (IAA) in vitro, and to evaluate their plant growthpromotion ability in greenhouse conditions by inoculation into pearl millet cultivated ina P-deficient soils without P fertilization, with Araxá rock phosphate or soluble triplesuperphosphate. All strains solubilized Fe-P and three of them produced carboxylate-typesiderophores and high levels of IAA in the presence of tryptophan. Positive effect of inocu-lation of some of these strains on shoot and root dry weight and the N P K content of plantscultivated in soil with no P fertilization might result from the synergistic combination ofmultiple plant growth promoting (PGP) traits. Specifically, while B1923 enhanced shoot androot dry weight and root N P content of plants cultivated with no P added, B2084 and B2088strains showed positive performance on biomass production and accumulation of N P K inthe shoot, indicating that they have higher potential to be microbial biofertilizer candidatesfor commercial applications in the absence of fertilization

Arborização urbana no semiárido: espécies potenciais na Caatinga.

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Efeito da interrupção da inundação da cultura do arroz na população do gorgulho-aquático e produção de grãos.

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Same Exposure but Two Radically Different Responses to Antibiotics: Resilience of the Salivary Microbiome versus Long-Term Microbial Shifts in Feces

Due to the spread of resistance, antibiotic exposure receives increasing attention. Ecological consequences for the different niches of individual microbiomes are, however, largely ignored. Here, we report the effects of widely used antibiotics (clindamycin, ciprofloxacin, amoxicillin, and minocycline) with different modes of action on the ecology of both the gut and the oral microbiomes in 66 healthy adults from the United Kingdom and Sweden in a two-center randomized placebo-controlled clinical trial. Feces and saliva were collected at baseline, immediately after exposure, and 1, 2, 4, and 12 months after administration of antibiotics or placebo. Sequences of 16S rRNA gene amplicons from all samples and metagenomic shotgun sequences from selected baseline and post-antibiotic-treatment sample pairs were analyzed. Additionally, metagenomic predictions based on 16S rRNA gene amplicon data were performed using PICRUSt. The salivary microbiome was found to be significantly more robust, whereas the antibiotics negatively affected the fecal microbiome: in particular, health-associated butyrate-producing species became strongly underrepresented. Additionally, exposure to different antibiotics enriched genes associated with antibiotic resistance. In conclusion, healthy individuals, exposed to a single antibiotic treatment, undergo considerable microbial shifts and enrichment in antibiotic resistance in their feces, while their salivary microbiome composition remains unexpectedly stable. The health-related consequences for the gut microbiome should increase the awareness of the individual risks involved with antibiotic use, especially in a (diseased) population with an already dysregulated microbiome. On the other hand, understanding the mechanisms behind the resilience of the oral microbiome toward ecological collapse might prove useful in combating microbial dysbiosis elsewhere in the body. IMPORTANCE Many health care professionals use antibiotic prophylaxis strategies to prevent infection after surgery. This practice is under debate since it enhances the spread of antibiotic resistance. Another important reason to avoid nonessential use of antibiotics, the impact on our microbiome, has hardly received attention. In this study, we assessed the impact of antibiotics on the human microbial ecology at two niches. We followed the oral and gut microbiomes in 66 individuals from before, immediately after, and up to 12 months after exposure to different antibiotic classes. The salivary microbiome recovered quickly and was surprisingly robust toward antibiotic-induced disturbance. The fecal microbiome was severely affected by most antibiotics: for months, health-associated butyrate-producing species became strongly underrepresented. Additionally, there was an enrichment of genes associated with antibiotic resistance. Clearly, even a single antibiotic treatment in healthy individuals contributes to the risk of resistance development and leads to long-lasting detrimental shifts in the gut microbiome

Inoculantes de microrganismos promotores de crescimento em milho: transferindo a diversidade do laboratório para o campo.

O milho é uma commoditie com grande volume de produção no mundo. No entanto, o sistema de produção dessa cultura é ainda altamente dependente de insumos químicos, particularmente em solos tropicais, onde fatores de estresses abióticos relacionados à fertilidade do solo limitam o crescimento e a produção vegetal. Tendo isso, a manutenção e/ou o aumento da competitividade dessa commoditie depende de inovações tecnológicas que permitam a sustentabilidade com a exploração de parâmetros como redução dos custos de produção, dos impactos ambientais e do uso de fontes não renováveis de energia. Diante desse cenário, o desenvolvimento de bioprodutos com aplicação na agricultura tem ganhado força, baseado na produção de insumos de base biológica que podem ser divididos em biofertilizantes, inoculantes e produtos utilizados no biocontrole de pragas e doenças. Países como Argentina, Canadá, África do Sul, Índia, Austrália, Filipinas, Estados Unidos e Brasil abraçaram estas tecnologias e têm investido nesta linha de bioprodutos visando reduzir o uso indiscriminado de agroquímicos e crescer a oferta de produtos que aumentem a tolerância das plantas a estresses de forma eficiente. Prosseguir com sucesso, do laboratório à escala industrial e no campo, é um dos principais desafios para o uso dos bioprodutos. Nem sempre os resultados promissores obtidos em bancadas são reproduzidos no campo, por causa da alta complexidade das interações inoculante-planta e inoculante-microbiota do solo. Com este desafio, cresce a demanda por novos produtos, microrganismos e rotas biotecnológicas capazes de suprir lacunas referentes ao desenvolvimento de inoculantes com fins agrícolas mais eficazes.bitstream/item/186427/1/doc-227.pd

Exact String Solutions in Nontrivial Backgrounds

We show how the classical string dynamics in $D$-dimensional gravity background can be reduced to the dynamics of a massless particle constrained on a certain surface whenever there exists at least one Killing vector for the background metric. We obtain a number of sufficient conditions, which ensure the existence of exact solutions to the equations of motion and constraints. These results are extended to include the Kalb-Ramond background. The $D1$-brane dynamics is also analyzed and exact solutions are found. Finally, we illustrate our considerations with several examples in different dimensions. All this also applies to the tensionless strings.Comment: 22 pages, LaTeX, no figures; V2:Comments and references added; V3:Discussion on the properties of the obtained solutions extended, a reference and acknowledgment added; V4:The references renumbered, to appear in Phys Rev.

Nonadditivity of critical Casimir forces

In soft condensed matter physics, effective interactions often emerge due to the spatial confinement of fluctuating fields. For instance, microscopic particles dissolved in a binary liquid mixture are subject to critical Casimir forces whenever their surfaces confine the thermal fluctuations of the order parameter of the solvent close to its critical demixing point. These forces are theoretically predicted to be nonadditive on the scale set by the bulk correlation length of the fluctuations. Here we provide direct experimental evidence of this fact by reporting the measurement of the associated many-body forces. We consider three colloidal particles in optical traps and observe that the critical Casimir force exerted on one of them by the other two differs from the sum of the forces they exert separately. This three-body effect depends sensitively on the distance from the critical point and on the chemical functionalisation of the colloid surfaces