1,077 research outputs found

    R-Process Nucleosynthesis In Neutrino-Driven Winds From A Typical Neutron Star With M = 1.4 Msun

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    We study the effects of the outer boundary conditions in neutrino-driven winds on the r-process nucleosynthesis. We perform numerical simulations of hydrodynamics of neutrino-driven winds and nuclear reaction network calculations of the r-process. As an outer boundary condition of hydrodynamic calculations, we set a pressure upon the outermost layer of the wind, which is approaching toward the shock wall. Varying the boundary pressure, we obtain various asymptotic thermal temperature of expanding material in the neutrino-driven winds for resulting nucleosynthesis. We find that the asymptotic temperature slightly lower than those used in the previous studies of the neutrino-driven winds can lead to a successful r-process abundance pattern, which is in a reasonable agreement with the solar system r-process abundance pattern even for the typical proto-neutron star mass Mns ~ 1.4 Msun. A slightly lower asymptotic temperature reduces the charged particle reaction rates and the resulting amount of seed elements and lead to a high neutron-to-seed ratio for successful r-process. This is a new idea which is different from the previous models of neutrino-driven winds from very massive (Mns ~ 2.0 Msun) and compact (Rns ~ 10 km) neutron star to get a short expansion time and a high entropy for a successful r-process abundance pattern. Although such a large mass is sometimes criticized from observational facts on a neutron star mass, we dissolve this criticism by reconsidering the boundary condition of the wind. We also explore the relation between the boundary condition and neutron star mass, which is related to the progenitor mass, for successful r-process.Comment: 14 pages, 2 figure

    Genetic variation of wheat landraces in Afghanistan

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    Genetic variation of wheat landraces in Afghanistan

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    Dissertação de mestrado em Ensino de Biologia e de Geologia no 3º Ciclo do Ensino Básico e no Ensino Secundário, apresentada ao Departamento de Ciências da Terra e Departamento de Ciências da VidaO presente relatório é referente ao período de Estágio Pedagógico, desenvolvido no âmbito do Mestrado em Ensino de Biologia e de Geologia no 3º Ciclo do Ensino Básico e no Ensino Secundário. O relatório descreve e analisa as atividades organizadas e desenvolvidas durante o estágio realizado na Escola Secundária D. Duarte, durante o ano letivo de 2013/2014. As práticas letivas foram circunscritas ao lecionamento supervisionado dos temas selecionados em Geologia e Biologia do 10º ano. Mais concretamente, os Métodos de estudo para o interior da geosfera e Vulcanologia e o Transporte nas plantas. Neste trabalho participaram alunos de duas turmas tendo sido lecionado o conteúdo de Geologia à turma A e o de Biologia à turma B. As estratégias e os recursos foram avaliados por intermédio de instrumentos de avaliação: diagnóstica (pré-teste e pós-teste, no início e final, respetivamente, de cada um dos períodos de lecionamento); sumativa (questões, específicas dos conteúdos selecionados, e integradas no terceiro e quinto teste sumativo); e questionários. Tanto em Geologia como em Biologia, verificou-se evolução positiva nos resultados do pré para o pós-teste. Relativamente aos testes sumativos, a avaliação foi diferenciada em procedimental e conceptual. Apesar dos resultados positivos a nível conceptual, os alunos revelaram muitas dificuldades a nível procedimental, provavelmente relacionado com o facto de a amostra ter uma média de idades inferior a 15 anos, não tendo sido preparados para o tipo de questões (itens de construção) utilizadas na avaliação procedimental. A análise dos resultados permitiu concluir que as estratégias e recursos tiveram influência na construção dos conhecimentos científicos de Geologia e Biologia. Nos questionários, os alunos também consideraram que as estratégias e recursos contribuíram para as suas aprendizagens. Neste trabalho, identificam-se as limitações das estratégias, dos recursos e dos procedimentos do docente, propondo-se possíveis alternativas e soluções.This report comprises the period of Pedagogical Training, developed within the framework of the Master in Teaching of Biology and Geology in the 3rd Cycle of Basic Education and Secondary Education. The report describes and analyzes the activities organized and carried out during the internship at D. Duarte High School, throughout the academic year of 2013/2014. The practices were confined to the supervised teaching of the selected themes in 10th grade Geology and Biology. Specifically, the Methods of study into the interior of the geosphere and Volcanology and Transport in plants. Students from two classes participated in this work, having been taught the content of Geology in class A and of Biology in class B. Strategies and resources were evaluated by means of assessment tools: diagnostic (pre-test and post-test, respectively in the beginning and end of each of the teaching periods); summative (specific questions of the selected content, and integrated in the third and fifth summative test); and questionnaires. It was ascertain, both in Biology and Geology, a positive development of the results from the pre to the post-test. Regarding summative tests, evaluation was differentiated as procedural and conceptual. Despite the positive results at the conceptual level, students revealed many difficulties in the procedural level, probably related to the fact that the age average of the sample was less than 15 years old and had not been prepared for the type of questions (building items) used in the procedural evaluation. The analysis of the results permitted to conclude that the strategies and resources influenced the construction of scientific knowledge of geology and biology. In the questionnaires, students also felt that the strategies and resources contributed to their learning. In this work are identified the limitations of the strategies, resources and teacher procedures, proposing possible alternatives and solutions

    Detection of serum soluble markers of immune activation in rheumatoid arthritis

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    The mutual correlation among soluble CD4 (sCD4), soluble CD8 (sCD8), and soluble CD23 (sCD23) has not yet been studied in patients with rheumatoid arthritis (RA), although previous studies have demonstrated that certain soluble markers of immune activation are elevated in RA. Thus, we examined this correlation based on the serum levels of sCD4, sCD8 and sCD23, and that of their levels with other serum markers such as immunoglobulin (Ig) subtypes (IgG, IgM and IgA), IgM-rheumatoid factor (IgM-RF) and C-reactive protein (CRP) in 25 RA patients, sCD4 was not elevated, whereas both sCD8 and sCD23 increased in RA patients compared with the healthy controls; a majority of RA patients, in particular, showed a high sCD23 level. The level of sCD23 showed a correlation with that of IgM-RF, but not with those of IgG, IgM, IgA and CRP. Importantly, a high level of sCD23 was not always accompartied with that of sCD8. The independent change between sCD23 and sCD8 levels was also observed in a one-year follow-up study of the two RA patients. These findings indicate that B cells might be generally activated in RA, whereas T-cell activation in variable in each patient with RA, suggesting that sCD23 is a more indicative marker for the immune status of RA patients than sCD8 from the clinical aspects

    Moderate exercise improves cognitive performance and decreases cortical activation in the go/no-go task

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    Background: A lot of studies have reported that physical activity has a beneficial influence not only on physical and mental disorders but also on cognitive and brain function. Performance of a go/no-go task improves after exercise. However, few studies have compared neural activity in a go/no-go task performed before and after exercise to identify brain regions that may respond to exercise and underlie this result. Therefore, the purpose of this study was to examine the brain blood flow and compare the cortical activation pattern during a go/no-go task performed before and after exercise.Method: Fifteen healthy subjects performed a go/no-go task before and after exercise. Functional near-infrared spectroscopy (fNIRS) was used to measure oxygenated hemoglobin concentration at 44 locations over both hemispheres. The exercise was of moderate intensity, defined as 50% of peak oxygen uptake.Result: The reaction time on the go/no-go task was significantly faster after exercise than before. The oxygenated hemoglobin concentration quantified across the whole brain was lower after exercise, and this was the case for go trials and no-go trials. In go trials, the oxygenated hemoglobin concentration in dorsolateral prefrontal cortex and supplementary motor area were significantly lower after exercise.Conclusion: These results suggest that the dorsolateral prefrontal cortex and supplementary motor area had lower activity in go trials in the go/no-go task performed after exercise than in go trials in the go/no-go task performed before exercise.ArticleBAOJ Medical and nursing.1(1):002(2015)journal articl

    Development and some applications of enzyme-linked immunosorbent assay system for murine macrophage inflammatory protein-2 (MIP-2)

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    We attempted to establish an enzyme-linked immunosorbent assay (ELISA) system by preparation of recombinant murine MIP-2 and its rabbit antibodies. A fusion construct of MIP-2 to protein A was used to enable easy purification as well as the generation of a sufficiently large antibody response. The specificity of antibody was confirmed by Western blotting analysis of 20-h conditioned medium from lipopolysaccharide (LPS)-stimulated RAW264.7 cells, a murine macrophage cell line; antibody gave a single band with a molecular weight of approximately 6000, which is identical to that of murine MIP-2 reported previously. Biotin–streptavidin sandwich ELISA could detect quantitatively MIP-2 at concentration range of 20 to 1000 pg/ml. In some applications of this ELISA system, time-related production of MIP-2 and inhibitory effect of dexamethasone on its production have been demonstrated in LPS-stimulated RAW264.7 cells. Thus, ELISA system established in this study is considered to be a useful tool to study MIP-2 response in various inflammation models in mice
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