258 research outputs found

    Nuclear pairing and Coriolis effects in proton emitters

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    We introduce a Hartree-Fock-Bogoliubov mean-field approach to treat the problem of proton emission from a deformed nucleus. By substituting a rigid rotor in a particle-rotor-model with a mean-field we obtain a better description of experimental data in 141^{141}Ho. The approach also elucidates the softening of kinematic coupling between particle and collective rotation, the Coriolis attenuation problem.Comment: 2 pages, 1 figur

    Diet and diving behaviour of European Storm Petrels Hydrobates pelagicus in the Mediterranean (ssp. melitensis).

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    Unlike Atlantic populations, which feed on krill, Mediterranean populations feed mainly on pelagic fish Gymnammodites cicerellus. European Storm Petrels in the Mediterranean exploit pelagic fish which are taken by diving. This contrasts with the Atlantic populations which feed mainly on krill. Mediterranean birds also feed on Opossum Shrimps Mysidacea during short foraging trips made at night just outside the colony. Differences in diet between long and short foraging trips may be because adults have to forage for both themselves and their chicks

    Driving calmodulin protein towards conformational shift by changing ionization states of select residues

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    Proteins are complex systems made up of many conformational sub-states which are mainly determined by the folded structure. External factors such as solvent type, temperature, pH and ionic strength play a very important role in the conformations sampled by proteins. Here we study the conformational multiplicity of calmodulin (CaM) which is a protein that plays an important role in calcium signaling pathways in the eukaryotic cells. CaM can bind to a variety of other proteins or small organic compounds, and mediates different physiological processes by activating various enzymes. Binding of calcium ions and proteins or small organic molecules to CaM induces large conformational changes that are distinct to each interacting partner. In particular, we discuss the effect of pH variation on the conformations of CaM. By using the pKa values of the charged residues as a basis to assign protonation states, the conformational changes induced in CaM by reducing the pH are studied by molecular dynamics simulations. Our current view suggests that at high pH, barrier crossing to the compact form is prevented by repulsive electrostatic interactions between the two lobes. At reduced pH, not only is barrier crossing facilitated by protonation of residues, but also conformations which are on average more compact are attained. The latter are in accordance with the fluorescence resonance energy transfer experiment results of other workers. The key events leading to the conformational change from the open to the compact conformation are (i) formation of a salt bridge between the N-lobe and the linker, stabilizing their relative motions, (ii) bending of the C-lobe towards the N-lobe, leading to a lowering of the interaction energy between the two-lobes, (iii) formation of a hydrophobic patch between the two lobes, further stabilizing the bent conformation by reducing the entropic cost of the compact form, (iv) sharing of a Ca+2 ion between the two lobes

    Changes in the biochemical and immunological components of serum and colostrum of overweight and obese mothers

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    Abstract\ud \ud Background\ud Obesity in pregnancy is associated with systemic inflammation, immunological changes and adverse maternal-fetal outcomes. Information on the association between maternal obesity and breast milk composition is scarce. This study describes changes and relationships between biochemical and immunological parameters of colostrum and serum of overweight and obese women.\ud \ud \ud Methods\ud Colostrum and blood samples were collected from 25 normal weight, 24 overweight and 19 obese women for determination of glucose, total protein, triglycerides, cholesterol, immunoglobulins, complement proteins (C3 and C4), fat and calorie content and C-reactive protein (CRP).\ud \ud \ud Results\ud Glucose was higher in colostrum of obese women (p = .002). In normal weight and obese women, total protein content was higher in colostrum than in serum (p = .001). Serum triglycerides (p = .008) and cholesterol (p = .010) concentrations were significantly higher in overweight and obese women than in their normal weight counterparts, but in colostrum their concentrations were similar across the three groups. Secretory IgA (sIgA) in colostrum and IgA in serum concentrations were significantly higher (p = .001) in overweight and obese mothers, whereas IgG and IgM concentrations did not vary among the groups (p = .825). Serum C3 (p = .001) and C4 (p = .040) concentrations were higher in obese women. No differences in colostrum complement proteins were detected among the groups. Calorie content (p = .003) and fat (p = .005) concentrations in colostrum and serum CRP (p = .002) were higher in obese women.\ud \ud \ud Conclusions\ud The results corroborate the hypothesis that colostrum of overweight and obese women undergoes biochemical and immunological changes that affect its composition, namely increasing glucose concentrations, calorie content, fat and sIgA concentrations.Fundação de Amparo a Pesquisa de São Paulo (FAPESP-No 2012-17843-8; No 2012-16662-0)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq-No 308702/2013-1; No 475238/2013-3

    Produção de forragem de populações de azevém anual em diferentes ambientes do Rio Grande do Sul.

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    O azevém anual (Lolium multiflorum Lam.) é uma das forrageiras mais utilizadas no RS durante o período frio do ano, seja na sobressemeadura em campos naturais, ou na formação de pastagens cultivadas. Porém, existem poucas cultivares registradas no Brasil. Assim, o objetivo do trabalho foi avaliar, em diferentes ambientes, algumas populações de azevém anual, visando a seleção de genótipos que apresentem um elevado potencial produtivo e o futuro lançamento de cultivares. Foram avaliadas sete populações, sendo comparadas com uma população comercial e com o cultivar LE-284. O experimento foi implantado em cinco diferentes regiões fisiográficas do RS e as variáveis analisadas foram produção de MS Total e produção de MS de Folhas, sendo procedida uma análise estatística conjunta para locais. A análise estatística indicou como significativa a interação local x população tanto para MS Total quanto para MS Folhas. A produção de MS Total não diferiu muito entre as populações na maioria dos locais. Porém, em alguns deles, a população Vacaria e o cultivar LE-284 apresentaram-se com produções inferiores. Por outro lado, as populações Trovão e Sarandi foram as melhores em Augusto Pestana e Eldorado do Sul, respectivamente. Quanto a produção de MS Folhas, a população comercial Comum-RS figurou entre as menos produtivas em todos os locais, exceto em São Gabriel, em função da sua maior precocidade reprodutiva

    Análise do Fluxo de Co2 sobre uma Cultura de Soja

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    Análise do fluxo de CO2 sobre uma cultura de soj
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