10 research outputs found
Modeling the Subsurface Structure of Sunspots
While sunspots are easily observed at the solar surface, determining their
subsurface structure is not trivial. There are two main hypotheses for the
subsurface structure of sunspots: the monolithic model and the cluster model.
Local helioseismology is the only means by which we can investigate
subphotospheric structure. However, as current linear inversion techniques do
not yet allow helioseismology to probe the internal structure with sufficient
confidence to distinguish between the monolith and cluster models, the
development of physically realistic sunspot models are a priority for
helioseismologists. This is because they are not only important indicators of
the variety of physical effects that may influence helioseismic inferences in
active regions, but they also enable detailed assessments of the validity of
helioseismic interpretations through numerical forward modeling. In this paper,
we provide a critical review of the existing sunspot models and an overview of
numerical methods employed to model wave propagation through model sunspots. We
then carry out an helioseismic analysis of the sunspot in Active Region 9787
and address the serious inconsistencies uncovered by
\citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find
that this sunspot is most probably associated with a shallow, positive
wave-speed perturbation (unlike the traditional two-layer model) and that
travel-time measurements are consistent with a horizontal outflow in the
surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic
Recent Developments in Helioseismic Analysis Methods and Solar Data Assimilation
MR and AS have received funding from the European Research Council under the European Unionâs Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 307117
ResistĂȘncia a antimicrobianos em Staphylococcus aureus isolados de mastite em bovinos leiteiros de Minas Gerais, Brasil
Produção de biofilme por Staphylococcus chromogenes isolados de amostras de leite provenientes de rebanhos bovinos com mastite
RESUMO Foram estudadas 135 vacas mestiças, provenientes de 10 rebanhos leiteiros no estado do Acre. O objetivo foi identificar espĂ©cies de Staphylococcus isoladas dos quartos mamĂĄrios de vacas com mastite e, posteriormente, avaliar a capacidade de produção de biofilme pela espĂ©cie Staphylococcus chromogenes. A caracterização dos isolados presentes nas amostras encontradas, correspondentes a Staphylococcus sp., foi realizada utilizando-se a tĂ©cnica do MALDI TOF MS (Matrix Associated Laser Desorption-Ionization - Time of Flight - Mass Spectrometry). Foram identificados: S. chromogenes (36), Staphylococcus saprophyticus (5), S. chromogenes ou Staphylococcus hycus (5), Staphylococcus haemolyticus (4), Staphylococcus epidermidis (3), Staphylococcus hycus (3), Staphylococcus aureus (1), Staphylococcus auriculares (1), Staphylococcus kloosii (1) e Staphylococcus xylosus (1). A espĂ©cie S. chromogenes correspondeu a 60% dos isolados do gĂȘnero (17 isolados coagularam o plasma de coelho no teste da coagulase em tubo), sendo 83,3% dos isolados (30/36) produtores de biofilme, nĂŁo estando esse fator de virulĂȘncia associado ao fenĂłtipo de coagulação do plasma. A identificação desses microrganismos Ă© importante para a elucidação da etiologia da mastite bovina. O alto percentual de S. chromogenes, produtores de biofilme, isolados de vacas com mastite Ă© um achado relevante e pode revelar uma mudança de perfil na colonização de agentes etiolĂłgicos causadores dessa enfermidade
Isolation, homology modeling and renal effects of a C-type natriuretic peptide from the venom of the Brazilian yellow scorpion (Tityus serrulatus)
Mammalian natriuretic peptides (NPs) have been extensively investigated for use as therapeutic agents in the treatment of cardiovascular diseases. Here, we describe the isolation, sequencing and tridimensional homology modeling of the first C-type natriuretic peptide isolated from scorpion venom. In addition, its effects on the renal function of rats and on the mRNA expression of natriuretic peptide receptors in the kidneys are delineated. Fractionation of Tityusserrulatus venom using chromatographic techniques yielded a peptide with a molecular mass of 2190.64Da, which exhibited the pattern of disulfide bridges that is characteristic of a C-type NP (TsNP, T. serrulatus Natriuretic Peptide). In the isolated perfused rat kidney assay, treatment with two concentrations of TsNP (0.03 and 0.1Όg/mL) increased the perfusion pressure, glomerular filtration rate and urinary flow. After 60min of treatment at both concentrations, the percentages of sodium, potassium and chloride transport were decreased, and the urinary cGMP concentration was elevated. Natriuretic peptide receptor-A (NPR-A) mRNA expression was down regulated in the kidneys treated with both concentrations of TsNP, whereas NPR-B, NPR-C and CG-C mRNAs were up regulated at the 0.1Όg/mL concentration. In conclusion, this work describes the isolation and modeling of the first natriuretic peptide isolated from scorpion venom. In addition, examinations of the renal actions of TsNP indicate that its effects may be related to the activation of NPR-B, NPR-C and GC-C. © 2013 Elsevier Ltd
Chemical composition and energy value of guava and tomato wastes for broilers chickens at different ages Composição quĂmica e valores energĂ©ticos dos resĂduos de goiaba e tomate para frangos corte em diferentes idades
The chemical composition and energy value of guava and tomato wastes for broilers at different ages were determined in this research. The metabolism assays were carried out by using the methodology of total excreta collection to calculate the chemical composition of wastes collected in different months. A total of 270 COBB broiler chicks was used: 150 in the period from 1 to 8 days of age (phase 1) and 120 chicks were used in the period from 10 to 17 days of age (phase 2). The trials were analyzed as completely randomized design with three treatments with five replications of 10 and 8 birds at the respective ages. The treatments consisted of different diets: one reference diet, one with 30% tomato meal and another with 20% guava meal, both partially replacing the reference diet. The values of the chemical composition of guava and tomato wastes varied according to the collection season. The chemical composition indicated that the wastes can be used in poultry feed, but with high crude fiber contents. The values of apparent metabolizable energy and nitrogen-corrected apparent metabolizable energy and of gross energy metabolizability coefficient of guava waste was not affected by the birds age, different from the result observed for tomato waste, whose digestibility coefficients and apparent metabolizable energy values varied among growing phases. The apparent metabolizable energy values (AME) for broilers form 1 to 8 and from 10 to 17 days of age were 1,331 and 1,358 kcal/kg for guava waste and from 2,351 to 2,465 kcal/kg for tomato waste.<br>Objetivou-se determinar a composição quĂmica e os valores nergĂ©ticos dos resĂduos de goiaba e de tomate para frangos de corte em diferentes idades. Os resĂduos foram coletados em meses distintos e, posteriormente, determinada a composição quĂmica por meio de ensaios de metabolismo utilizando a metodologia da coleta total de excretas. Utilizaram-se 270 pintos de corte da linhagem COBB, sendo 150 no perĂodo de 1 a 8 dias e 120 no perĂodo de 10 a 17 dias de idade. Nos ensaios utilizou-se o delineamento inteiramente casualizado e trĂȘs tratamentos com cinco repetiçÔes de 10 e 8 aves nas respectivas idades. Os tratamentos consistiram de trĂȘs dietas: uma dieta referĂȘncia, uma com 30% de farelo de tomate e outra com 20% de farelo de goiaba, ambas substituindo parte da ração referĂȘncia. Os valores de composição quĂmica dos resĂduos da goiaba e do tomate variaram quanto Ă Ă©poca de coleta. Os resĂduos apresentaram composição satisfatĂłria para alimentação de aves, porĂ©m com altos teores de fibra bruta. Os valores de energia metabolizĂĄvel o coeficiente de metabolizabilidade da energia bruta do resĂduo da goiaba nĂŁo sofreram influĂȘncia da idade das aves. Para o resĂduo de tomate os valores de energia metabolizĂĄvel aparente e coeficiente de metabolização variaram entre as idades. Os valores de energia metabolizĂĄvel aparente corrigida para pintos de corte de 1 a 8 e de 10 a 17 dias de idade foram de 1.331 e 1.358 kcal/kg para o resĂduo de goiaba e de 2.351 e 2.465 kcal/kg para o resĂduo de tomate
Prevalence, genetic diversity, and antimicrobial susceptibility profiles of Staphylococcus aureus isolated from bovine mastitis in Zhejiang Province, China
Effect of boron and zinc fertilization on white oats grown in soil with average content of these nutrients
The objective of this study was to evaluate the effect of fertilization with zinc or boron on the growth and dry matter production, nutritional value and accumulation of nutrients in white oats. The study comprised two experiments conducted in glasshouses, the first consisting of the application of four doses of zinc (0, 0.2, 0.4 and 0.6 mg/dmÂł) in the form of zinc sulphate (20% Zn), and the second consisting of the application of four doses of boron (0, 0.2, 0.4 and 0.6 mg/dmÂł) in the form of Borax (11% B). The experimental design in each case was a randomized block design, with five replicates. Fertilization with zinc and boron increased the growth of white oats, but had no significant effect on the nutritional value of the forage. Higher levels of absorption and accumulation of nutrients in plant tissues were observed following the application of boron and zinc at rates of up to 0.60 mg/dmÂł of soil