1,043 research outputs found

    Some thoughts about nonequilibrium temperature

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    The main objective of this paper is to show that, within the present framework of the kinetic theoretical approach to irreversible thermodynamics, there is no evidence that provides a basis to modify the ordinary Fourier equation relating the heat flux in a non-equilibrium steady state to the gradient of the local equilibrium temperature. This fact is supported, among other arguments, through the kinetic foundations of generalized hydrodynamics. Some attempts have been recently proposed asserting that, in the presence of non-linearities of the state variables, such a temperature should be replaced by the non-equilibrium temperature as defined in Extended Irreversible Thermodynamics. In the approximations used for such a temperature there is so far no evidence that sustains this proposal.Comment: 13 pages, TeX, no figures, to appear in Mol. Phy

    Rhizosphere microbial community manipulation under salted soil by the inoculation of Pseudomonas sp CMAA 1215 in Zea mays.

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    Soil salinity reduces the soil organic carbon stock, the microbial biomass and activity and modifies the biogeochemical cycle and the microbial diversity. Osmotic stress caused by ethylene on plants can be reduced using 1-aminocyclopropane-1-carboxylate (ACC) deaminase plant growth promoting bacteria (PGPR) producers. Studies of PGPR and commercially strains are based only on the growth of the plant without concern about modification of the microbial community. This scenario has shown an increasing need to study the ecological functions of bacterial community on salted soil and to develop new technologies to reduce environmental impacts and waste of natural resources. Our aim was to study the influence of the Pseudomonas sp. CMAA1215, a known ACC deaminase on rhizosphere bacteria community of Zea mays under saline soil by sequencing the rhizosphere metagenome. The NMDS of the OTU table (ANOSIM p<0.01) discriminate all the treatments (with and without inoculation under salted and non-salted soils) indicating a modification of the bacteria community by inoculation or by soil salinization. The main groups of the rhizosphere that had the abundance increased by Pseudomonas inoculation were Acidobacteriales, Solibacteriales, Bacillales and Rhizobiales. The relative abundance of Rhodospirillales (Alphaproteobacteria) and Chthoniobacterales (Spartobacteria) was stimulated by the inoculation only under higher salinization. The inoculation can be important to stimulate other PGPR under saline soil or microbes that are not benefic to plants

    Change in enzymatic activity of microbial communities on the seasonal differences in soils the of biomes caatinga and atlantic forest.

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    Abstract: The average global temperature has increased and will continue increasing, with forecast of up to 5.8° C by the end of this century as a result of the increase in the concentration of greenhouse gases in the atmosphere. Due to these increased temperature, some biomes may introduce features of arid and semi-arid environments in the coming years. The patterns of water availability in the soil can select groups of microorganisms with physiological strategies to tolerate these seasonal changes. Nutrient availability for plants becomes limited when the aqueous part of the soil is low in the dry period. On the other hand, in irrigated soils the concentration of nutrients available associated with mineralization increases rapidly. Environmental indicators such as seasonal variations in the enzymatic activity, the abundance of microorganisms and soil physical and chemical characteristics, are useful to measure and analyze the change of the functionality soil microbiota. This work was aimed to study the seasonal changes of enzymatic activity (dehydrogenase, acid phosphatase and alkaline, arylsulfatase, phytase, cellulase, amylase and urease) of microbial communities in soils of Caatinga and Atlantic Forest. The soils were collected in Bertioga-SP, Cananéia-SP, Juazeiro-BA and Petrolina-PE. The samples of soil were sifted and separated into 18 glass bottles of 200 mL containing 50 g of each soil. The bottles were incubated at 28° C varying moisture in 60% and 30% every 14 days corresponding to three seasonal cycles. The sequencing of 16S ribosomal RNA gene (rRNA) of samples was performed using the Ion Sequencing Kit 400 (Life Technologies). The dynamics of the bacterial communities had influences of seasonal changes, especially when compared the biogeographic patterns. The effect of moisture was significantly different (p < 0.05) only to the activity of alkaline phosphatase and phytase enzymes. The activity of all enzymes, except phytase, was important to discriminate the soils between Caatinga and Atlantic Forest biomes. Seasonality had an effect on the enzymatic activity that was related with the functional change in the soil microbiota

    The morita-baylis-hillman reaction: advances and contributions from brazilian chemistry

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    The Morita-Baylis-Hillman reaction is an organocatalyzed chemical transformation that allows access to small poly-functionalized molecules and has considerable synthetic potential and promising biological profiles. In this review, we report the efforts made by Brazilian research groups in recent years on the development of Morita-Baylis-Hillman chemistry. The review covers these contributions, with a focus on mechanistic studies, improvement of the experimental conditions, and the use of Morita-Baylis-Hillman adducts as building blocks for the synthesis of heterocycles, natural products and drugs126830852CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2013/10449-5; 2013/07600-5; 2012/08048-

    Curtimento de pele ovina passo a passo.

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    Cuidados a serem observados antes do curtimento; Primeira etapa do curtimento; Segunda etapa; Terceira etapa (lavagem e remolho); Quarta etapa (engraxamento); Quinta etapa (acabamento).bitstream/item/55740/1/it05-2000.pd

    Morfometria celular na análise da qualidade de grãos de café nas etapas do processamento via úmida e durante o armazenamento.

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    Objetivou-se com este trabalho avaliar a qualidade do café (Coffea arabica L.), obtido de quatro etapas do processamento via úmida, utilizando-se morfometria celular (por análise da estrutura anatômica do endosperma), prova de xícara e características físicas dos grãos. Foi utilizado café da variedade Catuaí Vermelho, obtido de propriedade comercial da região da Zona da Mata de Minas Gerais e processado por via úmida. Procedeu-se uma limpeza retirando folhas, galhos e pedras misturados aos frutos e, em seguida, retirou-se uma quantidade de frutos de café para a composição da amostra ?Lavador? (etapa 1). Em seguida, os frutos cerejas e verdes foram separados dos frutos bóias e outra amostra foi retirada, composta pelos frutos mais densos (cereja e verde), sendo denominada ?Separador? (etapa 2). Na sequência, os frutos seguiram para o descascador e, após terem sido descascados, retirou-se a terceira amostra, ?Descascador? (etapa 3). Os grãos de café cereja envolvidos apenas com o pergaminho e a mucilagem passaram pela desmucilagem mecânica por meio do atrito entre os grãos e entre os grãos e um cilindro metálico e foi obtido o café desmucilado, etapa denominada ?Desmucilador? (etapa 4). Foram analisados o teor de água dos grãos, a qualidade da bebida, a estrutura anatômica do endosperma (quantificada pelo número de paredes celulares do endosperma rompidas), a integridade das paredes celulares pelo teste de condutividade elétrica, a massa específica aparente e o pH. A partir dos resultados obtidos concluiu-se que: não foi possível obter uma relação direta entre a etapa de processamento via úmida do café e o aumento do número de paredes celulares rompidas, quantificadas pela morfometria; a análise da morfometria celular refletiu a qualidade pelo teste de bebida sendo esta técnica útil para relacionar a estrutura anatômica do endosperma dos grãos com a qualidade; a bebida apresentou menor padrão de qualidade na etapa 1 (classificado como ?Duro?) em relação às demais que apresentaram padrão ?Mole? ou ?Apenas mole?; a etapa que apresentou a melhor qualidade durante o armazenamento pelas características físicas (cor e massa especifica aparente) e químicas (pH) foi a etapa 3 (?Descascador?)
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