34,741 research outputs found
Breast pathology: evaluation of the Portuguese scientific activity based on bibliometric indicators
Introdução e Objectivos A análise bibliométrica da produção científica portuguesa na área da patologia da mama durante os anos de 1995 à actualidade (Julho de 2005) dá-nos a visão sobre a actividade científica desenvolvida nesta temática e possibilita a caracterização de alguns aspectos relevantes e a sua evolução temporal. Material e Métodos Estudaram-se os documentos recolhidos da produção científica nacional na área da patologia mamária entre 1995 e Julho de 2005 em 3 bases de dados, Medline (com interface de pesquisa PubMed), Science Citation Index e Índex das Revistas Médicas Portuguesas. A partir do número de artigos encontrados e das revistas onde foram publicados aplicámos indicadores bibliométricos quantitativos e qualitativos. Os indicadores quantitativos baseados no número de artigos publicados, dão-nos a posição de Portugal na área da patologia da mama dentro da comunidade científica internacional, assim como, conhecer a participação das distintas instituições e organismos nacionais e das áreas geográficas na produção científica, e também a determinação da colaboração internacional. Com os indicadores qualitativos estudámos a influência, a visibilidade da produção científica. São indicadores baseados na classificação das revistas onde estão publicados os artigos e nas citações que receberam. Utilizámos o Science Citation Índex para determinar o número de citações obtidas pelos artigos que recolhemos nas pesquisas efectuadas. E o Factor de Impacto (FI) das revistas publicado anualmente no Journal Citation Reports (JCR). Apesar de todas as suas limitações é difícil não aceitar a opinião que o Factor de Impacto constitui na actualidade um dos poucos meios, se não o único, para avaliar a influência de uma revista no mundo científico internacional. Resultados Durante o período estudado a produção científica portuguesa na área que seleccionámos teve um crescimento de 200 %. Analisaram-se 348 documentos (232 publicados nas bases de dados internacionais que seleccionámos e 116 na base de dados nacional). Artigos publicados por um só autor são em número muito reduzido, n=6, a forma mais comum de publicar é em co-autoria. A produção de artigos concentrou-se em 59% na zona Norte, 26% zona Sul e 15% na zona Centro. As instituições nacionais que mais publicam em revistas de prestígio internacionais são IPATIMUP, IPO Porto e IPO Lisboa. As instituições que publicam o maior número de trabalhos em revistas portuguesas são Hospitais e Centros de Saúde. As revistas estrangeiras seleccionadas pelos produtores de ciência nacionais gozam de um factor de impacto elevado. De todos os artigos recolhidos nas bases de dados internacionais num total de 232, 81 não foram citados e 120 obtiveram um total de 1.856 citações. Convém realçar que os artigos mais recentes ainda não têm citações. Os artigos efectuados em colaboração internacional obtiveram um maior número de citações. Conclusões Observa-se uma crescente visibilidade da investigação nesta temática, avaliada pelo incremento experimentado no número de artigos publicados em revistas internacionais de prestígio. Tendência em publicar em revistas com maior factor de impacto e o crescente papel da co-autoria e colaboração internaciona
Bibliometry of Cancer in Portugal: 1997 to 2006
Introdução: Analisou-se a produção científica das instituições portuguesas na área específica da Oncologia, durante um período de 10 anos, 1997 a 2006.
Verificou-se a contribuição dos autores nacionais na produção científica internacional, o que permitiu julgar e quantificar a importância de autores, departamentos, instituições e investigações científicas.
Material e Métodos: Usando a versão de 2006 da Web of Science,a secção Science Citation Index, base de dados de referências bibliográficas que permite análise de citações, e do Journal Citation Reports, ferramentas produzidas pela ISI Thomson Scientific, realizou-se uma análise quantitativa e qualitativa da produção científica portuguesa sobre o cancro entre o período de 1997 a 2006.
Resultados: Durante o período estudado produziram-se 1.811 artigos publicados em revistas com factor de impacto atribuído, que obtiveram um total de 24.803 citações, o que dá uma média de 13,70 citações por artigo.
Entre 1997 e 2006 verificou-se um crescimento de 202% da produção científica nacional na área que seleccionámos.
Dez autores são responsáveis por 45% dos documentos produzidos.
A maioria dos trabalhos publicados foram realizados pelas Universidades, sendo a Universidade do Porto a que mais publicou.
A regra na produção de artigos é a co-autoria, e Portugal não é excepção.
Os artigos efectuados em colaboração internacional foram os que obtiveram um maior número de citações.
A contribuição portuguesa para a produção científica internacional na área da Oncologia no período estudado foi de 1,8%.
Conclusões: A análise bibliométrica é um recurso credível para avaliar o desenvolvimento e a qualidade da produção científica.
Observou-se uma crescente visibilidade da investigação nesta temática, avaliada pelo aumento do número de artigos publicados em revistas internacionais de grande prestígio reconhecido.
Os autores nacionais publicam poucos trabalhos, mas fazem-no em revistas de qualidade
Evaluation of portuguese scientific activity in obstetrics and gynecology based on bibliometric indicators
Erosional effects on runout of fast landslides, debris flows and avalanches: A numerical investigation
The mechanism of mass changes in debris transportation process is an important topic in the study of fast landslides, debris flows and avalanches. Basal erosion is recognised as a dynamic interaction between the original moving material and the entrained basal topsoil shearing along their non-slip contact surface. In this paper we propose a new concept of yield rate and establish the erosional relationship to bridge these two systems. A pertinent mathematical model and numerical implementation are formulated. Parametric numerical experiments are conducted to compare the erosional effects. The simulated results are consistent with available experimental and field observations. The influence of the involvement of the erosive material on runout behaviour and the global mobility of the moving material are elucidated. The proposed method is then employed to analyse a recent debris flow event in northern Italy. The excellent match to the field data gives it a plausible potential application to the analysis of this type of gravity-driven flow with significant erosion. Defined in a dimensionless form, the proposed yield rate can be estimated conveniently in general geotechnical practices.published_or_final_versio
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Gladstone and Scott: Family, identity, and nation
In the 175 years since his death, Walter Scott has regularly been hailed as an influence by politicians. Amongst the poet-novelist's nineteenth-century political admirers, William Ewart Gladstone was possibly the most ardent, genuine, and significant. Scott's poems and novels were amongst the earliest texts Gladstone read; he read no works (in English), except the Bible, so consistently or completely over such a length of time. They offered him a plethora of inspirations, ideas, and language, which he imbibed and appropriated into his public and private lives. His concept of self, his understanding of family, and his sense of home, were all forged and conducted within a Scottian frame of reference. Scott's life and works also crucially influenced Gladstone's political understanding of the Scottish nation and its people, and his conception of how he could best serve their political interests. This article casts new light on an important and influential relationship in Gladstone's life, establishing that it was neither the superficial and recreational association some have described, nor simply a ploy of an astute politician. The article falls into three parts. The first elucidates how Gladstone's consumption of Scott's writings was seminal in the formation of his private identity, both individual and familial. The second explains how Gladstone's readings of Scott fitted into the specific and serious character of his other reading and knowledge-gathering, and the third shows how the details of Gladstone's response to Scott related to the broader intellectual and cultural context of his public life. By placing Gladstone within his Scottish context, this article shows how frequently and significantly his private and public worlds intersected
A Rapid Dynamical Monte Carlo Algorithm for Glassy Systems
In this paper we present a dynamical Monte Carlo algorithm which is
applicable to systems satisfying a clustering condition: during the dynamical
evolution the system is mostly trapped in deep local minima (as happens in
glasses, pinning problems etc.). We compare the algorithm to the usual Monte
Carlo algorithm, using as an example the Bernasconi model. In this model, a
straightforward implementation of the algorithm gives an improvement of several
orders of magnitude in computational speed with respect to a recent, already
very efficient, implementation of the algorithm of Bortz, Kalos and Lebowitz.Comment: RevTex 7 pages + 4 figures (uuencoded) appended; LPS preprin
Tillage Frequency, Soil Compaction and N-Fertilizer Rate Effects on Yield of Teff (Eragrostis Tef (Zucc) Trotter) in Central Zone of Tigray, Northern Ethiopia
In Ethiopia, teff is grown for its grain and straw. There is a dearth of information with respect to plowing, compaction and fertilization on vertisols in central zone of Tigray. Therefore, this study was conducted to determine the effects of plowing frequency, soil compaction and N on teff yields. The experimental design was a split-split plot where main plot was plowing frequency with three levels (once, twice and thrice); sub-plot was compaction with two levels (with and without compaction) and sub-sub plot was N-fertilizer rate with four levels (0kg N/ha, 46Kg N/ha, 69Kg N/ha and 92Kg N/ha). There were three replications. Results showed that plowing frequency had no significant effect on most of the yield components except on tillering when the soil is compacted. Maximum average number of tillers per plant (2.75) was obtained from compacted plots plowed two times. Compaction affected almost all yield and yield components significantly. Higher number of tillers per plant (2.64) from non compacted plots and higher stand cover (about 94%) from compacted plots were found. In addition, maximum biomass (4210.617 kg/ha) and grain (1221.98 kg/ha) yields were obtained from compacted plots due to enhanced soil to seed contact resulting in increased plant population. Nitrogen fertilizer significantly increased grain yield and yield components. Maximum stand cover (94.78%), plant height (92.16cm), panicle length (37.75cm), biomass yield (4724 kg/ha) and grain yield (1387.9 kg/ha) were found from plots receiving 92kgN/ha. Partial budget analysis of N fertilizer rates indicted that higher marginal rate of return (525%) were found by applying 69kg N/ha. It is recommended that farmers use 69kg N/ha so as to get economically feasible returns and yield.
Keywords: Compaction, Fertilizer N, Plowing frequency, Teff, Vertisol
A Trial of a 7-Valent Pneumococcal Conjugate Vaccine in HIV-Infected Adults.
BACKGROUND: Streptococcus pneumoniae is a leading and serious coinfection in adults with human immunodeficiency virus (HIV) infection, particularly in Africa. Prevention of this disease by vaccination with the current 23-valent polysaccharide vaccine is suboptimal. Protein conjugate vaccines offer a further option for protection, but data on their clinical efficacy in adults are needed. METHODS: In this double-blind, randomized, placebo-controlled clinical efficacy trial, we studied the efficacy of a 7-valent conjugate pneumococcal vaccine in predominantly HIV-infected Malawian adolescents and adults who had recovered from documented invasive pneumococcal disease. Two doses of vaccine were given 4 weeks apart. The primary end point was a further episode of pneumococcal infection caused by vaccine serotypes or serotype 6A. RESULTS: From February 2003 through October 2007, we followed 496 patients (of whom 44% were male and 88% were HIV-seropositive) for 798 person-years of observation. There were 67 episodes of pneumococcal disease in 52 patients, all in the HIV-infected subgroup. In 24 patients, there were 19 episodes that were caused by vaccine serotypes and 5 episodes that were caused by the 6A serotype. Of these episodes, 5 occurred in the vaccine group and 19 in the placebo group, for a vaccine efficacy of 74% (95% confidence interval [CI], 30 to 90). There were 73 deaths from any cause in the vaccine group and 63 in the placebo group (hazard ratio in the vaccine group, 1.18; 95% CI, 0.84 to 1.66). The number of serious adverse events within 14 days after vaccination was significantly lower in the vaccine group than in the placebo group (3 vs. 17, P=0.002), and the number of minor adverse events was significantly higher in the vaccine group (41 vs. 13, P=0.003). CONCLUSIONS: The 7-valent pneumococcal conjugate vaccine protected HIV-infected adults from recurrent pneumococcal infection caused by vaccine serotypes or serotype 6A. (Current Controlled Trials number, ISRCTN54494731.) Copyright 2010 Massachusetts Medical Society
Spin texture and magnetoroton excitations at nu=1/3
Neutral spin texture (ST) excitations at nu=1/3 are directly observed for the first time by resonant inelastic light scattering. They are determined to involve two simultaneous spin flips. At low magnetic fields, the ST energy is below that of the magnetoroton minimum. With increasing in-plane magnetic field these mode energies cross at a critical ratio of the Zeeman and Coulomb energies of eta(c)=0.020 +/- 0.001. Surprisingly, the intensity of the ST mode grows with temperature in the range in which the magnetoroton modes collapse. The temperature dependence is interpreted in terms of a competition between coexisting phases supporting different excitations. We consider the role of the ST excitations in activated transport at nu=1/3
Advanced Post-Processing and Correlation Analyses in High-Velocity Air-Water Flows
The interest in air-water flows has not diminished in recent years, but it is accompanied by frequent citations of early, sometimes outdated articles. A basic issue is the inadequate, incomplete interpretation of air-water flow instrumentation by hydraulic engineers and researchers. This article comments on high-velocity air-water flow measurements by means of intrusive phase detection probes. This article focus on the bubbly flow structure of high-velocity air-water flow based upon measurements by means of intrusive phase detection probes. It is shown that some advanced post-processing techniques may yields expanded information on the air-water turbulent flow properties and bubbly flow structures. The outcomes demonstrate simple techniques in high-velocity air-water flow analysis
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