522 research outputs found
Efeitos da aplicação do efluente municipal tratado sobre os atributos químicos do substrato da gérbera.
Este estudo visa avaliar os efeitos da aplicação do efluente municipal tratado sobre os atributos químicos do substrato cultivado da gérbera em ambiente protegido, no período de julho a outubro de 2007, em Teresina, PI. O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e cinco repetições. Foram aplicados diferentes volumes de água residuária tratada associados a fertilizantes químicos (N e K2O). Os elementos que apresentaram maior aumento, após a aplicação do efluente tratado ocorreram no tratamento com apenas volume de água residuária: pH (5,24 para 5,76), Ca2+(1,71 para 3,14 cmolc dm-3), Mg2+ (1,03 para 1,44 cmolc dm-3) e S (3,11 para 4,87 cmolc dm-3). A aplicação do efluente doméstico tratado no substrato cultivado não ocasionou alterações nos atributos químicos que viessem a provocar efeitos prejudiciais na cultura da gérbera
Efficiency of biological control for fall armyworm resistant to the protein Cry1F.
O entendimento de relações ecológicas e toxicológicas envolvendo culturas geneticamente modificadas (GM) e agentes de controle biológico é de grande importância para discussões relativas à compatibilidade de culturas GM com estratégias de manejo integrado e manejo de resistência de pragas. Este trabalho avaliou o comportamento de busca e a capacidade predatória de Orius insidiosus (Say) (Hemiptera: Anthocoridae) e Doru luteipes (Scudder) (Dermaptera: Forficulidae) sobre ovos e lagartas de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistente ou não à proteína Cry1F expressa em milho Bt. Para determinar o tempo de busca foi utilizado um cronômetro que foi disparado até a captura da primeira presa; a capacidade de predação foi avaliada através da contagem das presas remanescentes 24 h após infestação. Também foram avaliadas as injúrias de S. frugiperda em milho transgênico e milho convencional na presença ou ausência dos predadores. Os predadores não foram capazes de distinguir entre presas (ovos ou lagartas) resistentes e suscetíveis, considerando os comportamentos predatórios avaliados. Não houve diferença no tempo de busca e capacidade predatória sobre ovos e lagartas de S. frugiperda resistente ou suscetível entre os predadores. Na presença dos predadores, as notas de injúria de S. frugiperda resistente nas plantas de milho Bt foram menores. Conclui-se que O. insidiosus e D. luteipes não percebem a presença da proteína Cry1F na presa S. frugiperda, o que pode contribuir para o uso integrado de milho GM e controle biológico em programas de manejo integrado e manejo de resistência de pragas.Ahead of print
Spatial variability of litter temperature, relative air humidity and skin temperature of chicks in a commercial broiler house
ArticleThe thermal environment inside a broiler house has a great influence on animal welfare
and productivity during the production phase. Among the importance of the chicken litter is the
function of absorbing moisture, provide thermal insulation and provide a soft surface for broilers.
The skin temperature is an important physiological parameter to quantify the thermal comfort of
animals, its variations may occur as a function of thermal variables. So, the aim of this work was
to analyse the magnitude and spatial variability of chicken litter temperature and relative humidity
of the air and to correlate them with the spatial distribution of chicks’ skin surface temperature
throughout the broiler house during the 7th, 14th and 21st days of the chicks’ life, using
geostatistical techniques. The experiment was performed in a commercial broiler house located
in the western mesoregion of Minas Gerais, Brazil, where 28,000 male Cobb chicks were housed.
The heating system consisted of an industrial indirect-fired biomass furnace. The heated air was
inflated by an AC motor, 2,206 W of power, 1,725 RPM. Geostatistical techniques were used
through semivariogram analysis and isochore maps were generated through data interpolation by
kriging. The semivariogram was fitted by the restricted maximum likelihood method. The used
mathematical model was the spherical one. After fitting the semivariograms, the data were
interpolated by ordinary kriging. The semivariograms along with the isochore maps allowed
identifying the non-uniformity of spatial distribution of the broiler litter temperature throughout
the broiler house for 3 days of chicks’ life. It was observed that skin surface presented a positive
correlation with the litter temperature and a negative correlation with the air humidity. The
semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial
distribution of the litter temperature, air humidity and skin temperature of chicks throughout the
broiler aviary for the three days. In addition, the use of geostatistics and distribution maps made
possible to identify different environmental conditions in regions inside the broiler house that
may harm the development of chicks
Utilização do plástico preto, farelo de mamona e nim no manejo de fitonematóides em mudas de mamoeiro.
Avaliação hematológica de tambaqui (Colossoma macropomum) alimentado com farelo do coco.
Resumo simples
Crystalline Assemblies and Densest Packings of a Family of Truncated Tetrahedra and the Role of Directional Entropic Forces
Polyhedra and their arrangements have intrigued humankind since the ancient
Greeks and are today important motifs in condensed matter, with application to
many classes of liquids and solids. Yet, little is known about the
thermodynamically stable phases of polyhedrally-shaped building blocks, such as
faceted nanoparticles and colloids. Although hard particles are known to
organize due to entropy alone, and some unusual phases are reported in the
literature, the role of entropic forces in connection with polyhedral shape is
not well understood. Here, we study thermodynamic self-assembly of a family of
truncated tetrahedra and report several atomic crystal isostructures, including
diamond, {\beta}-tin, and high- pressure lithium, as the polyhedron shape
varies from tetrahedral to octahedral. We compare our findings with the densest
packings of the truncated tetrahedron family obtained by numerical compression
and report a new space filling polyhedron, which has been overlooked in
previous searches. Interestingly, the self-assembled structures differ from the
densest packings. We show that the self-assembled crystal structures can be
understood as a tendency for polyhedra to maximize face-to-face alignment,
which can be generalized as directional entropic forces.Comment: Article + supplementary information. 23 pages, 10 figures, 2 table
Morphology of supported polymer electrolyte ultra-thin films: a numerical study
Morphology of polymer electrolytes membranes (PEM), e.g., Nafion, inside PEM
fuel cell catalyst layers has significant impact on the electrochemical
activity and transport phenomena that determine cell performance. In those
regions, Nafion can be found as an ultra-thin film, coating the catalyst and
the catalyst support surfaces. The impact of the hydrophilic/hydrophobic
character of these surfaces on the structural formation of the films has not
been sufficiently explored yet. Here, we report about Molecular Dynamics
simulation investigation of the substrate effects on the ionomer ultra-thin
film morphology at different hydration levels. We use a mean-field-like model
we introduced in previous publications for the interaction of the hydrated
Nafion ionomer with a substrate, characterized by a tunable degree of
hydrophilicity. We show that the affinity of the substrate with water plays a
crucial role in the molecular rearrangement of the ionomer film, resulting in
completely different morphologies. Detailed structural description in different
regions of the film shows evidences of strongly heterogeneous behavior. A
qualitative discussion of the implications of our observations on the PEMFC
catalyst layer performance is finally proposed
The effect of thermal, chlorine and ozone treatments on survival of Escherichia coli and Salmonella spp. in açai berries.
Açai berries (Euterpe oleracea Mart.) have a high natural microbial load that can compromise the quality of their products. In this study, test microorganisms were inoculated on raw açai berries in drip trials, with five strains of Salmonella spp. and E. coli, separately. Açai berries sanitizing processes were: i) chlorination with 200 mg.L-1 for a period of 15 min; ii) blanching at 80 °C for 10 s (regional legislation); iii) blanching at 90 °C for 10 s; iv) aqueous ozonation at 4 mg.L-1 for 5 min; and v) washing with distilled water for 15 min as control treatment. Thermal treatment at 90 °C 10 s achieved the highest efficiency in reducing counts of E.coli (3.0 ± 0.8 log CFU.mL-1). In Salmonella spp., all sanitizing treatments were similar and better than simple washing with water. Thus, blanching of açai berries at 90 °C 10 s, with immediate cooling with chlorinated water (50 mg.L-1), is an alternative process for sanitization for açai berries, considering the application of good manufacturing practices
Effects of exposure to cigarette smoke prior to pregnancy in diabetic rats
<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to evaluate the effects of cigarette smoke exposure before pregnancy on diabetic rats and their offspring development.</p> <p>Methods</p> <p>Diabetes was induced by streptozotocin and cigarette smoke exposure was conducted by mainstream smoke generated by a mechanical smoking device and delivered into a chamber. Diabetic female Wistar rats were randomly distributed in four experimental groups (n minimum = 13/group): nondiabetic (ND) and diabetic rats exposed to filtered air (D), diabetic rats exposed to cigarette smoke prior to and into the pregnancy period (DS) and diabetic rats exposed to cigarette smoke prior to pregnancy period (DSPP). At day 21 of pregnancy, rats were killed for maternal biochemical determination and reproductive outcomes.</p> <p>Results</p> <p>The association of diabetes and cigarette smoke in DSPP group caused altered glycemia at term, reduced number of implantation and live fetuses, decreased litter and maternal weight, increased pre and postimplantation loss rates, reduced triglyceride and VLDL-c concentrations, increased levels of thiol groups and MDA. Besides, these dams presented increased SOD and GSH-Px activities. However, the increased antioxidant status was not sufficient to prevent the lipid peroxidation observed in these animals.</p> <p>Conclusion</p> <p>Despite the benefits stemming from smoking interruption during the pregnancy of diabetic rats, such improvement was insufficient to avoid metabolic alterations and provide an adequate intrauterine environment for embryofetal development. Therefore, these results suggest that it is necessary to cease smoking extensive time before planning pregnancy, since stopping smoking only when pregnancy is detected may not contribute effectively to fully adequate embryofetal development.</p
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