Collaboration networks from a large CV database: dynamics, topology and bonus impact

Understanding the dynamics of research production and collaboration may reveal better strategies for scientific careers, academic institutions and funding agencies. Here we propose the use of a large and multidisciplinar database of scientific curricula in Brazil, namely, the Lattes Platform, to study patterns of scientific production and collaboration. In this database, detailed information about publications and researchers are made available by themselves so that coauthorship is unambiguous and individuals can be evaluated by scientific productivity, geographical location and field of expertise. Our results show that the collaboration network is growing exponentially for the last three decades, with a distribution of number of collaborators per researcher that approaches a power-law as the network gets older. Moreover, both the distributions of number of collaborators and production per researcher obey power-law behaviors, regardless of the geographical location or field, suggesting that the same universal mechanism might be responsible for network growth and productivity.We also show that the collaboration network under investigation displays a typical assortative mixing behavior, where teeming researchers (i.e., with high degree) tend to collaborate with others alike. Finally, our analysis reveals that the distinctive collaboration profile of researchers awarded with governmental scholarships suggests a strong bonus impact on their productivity.Comment: 8 pages, 8 figure

Tactical Voting in Plurality Elections

How often will elections end in landslides? What is the probability for a head-to-head race? Analyzing ballot results from several large countries rather anomalous and yet unexplained distributions have been observed. We identify tactical voting as the driving ingredient for the anomalies and introduce a model to study its effect on plurality elections, characterized by the relative strength of the feedback from polls and the pairwise interaction between individuals in the society. With this model it becomes possible to explain the polarization of votes between two candidates, understand the small margin of victories frequently observed for different elections, and analyze the polls' impact in American, Canadian, and Brazilian ballots. Moreover, the model reproduces, quantitatively, the distribution of votes obtained in the Brazilian mayor elections with two, three, and four candidates.Comment: 7 pages, 4 figure

Pastagens no Trópico Úmido.

bitstream/item/19074/1/Doc-241.pdfVersão eletrônica. 1ª impressão: 2009

Impacto da gliricidia Sepium na caracterização química do solo em sistemas agroflorestais no Estado de Sergipe.

O presente trabalho tem por objetivo avaliar o impacto da espécie florestal Gliricídia (Gliricídia Sepium) nas características químicas do solo, em seis localidades no estado de Sergipe em Nossa Senhora da Glória (Alto Sertão sergipano), Nossa Senhora das Dores (Médio Sertão Sergipano), Salgado (Centro Sul Sergipe), Pacatuba (Baixo São Francisco), Tobias Barreto e Simão Dias (Sertão Ocidental) comparando com áreas de pastagens. Amostras de solo para avaliação química foram coletadas onde serão analisadas pH em água; extração com KCl 1M: Cálcio, Magnésio e Alumínio; Extração com solução de Mehlich1: Fósforo, Potássio, Sódio e Micronutrientes; Matéria Orgânica. Espera-se que a Gliricídia tenha impacto positivo comparado a solos sobre o manejo de pastagem

Uso da gliricídia (Gliricídia sepium) como componente forrageiro em sistemas agropecuários sustentáveis.

Objetivou-se avaliar a composição bromatológica da gliricídia implantada em diferentes condições climáticas e sistemas de plantio, permitindo realizar recomendações de suplementação de acordo com as composições apresentadas. As coletas foram realizadas em áreas de produtores beneficiados pelo Projeto Sistema Agropecuário Sustentável, implantados em municípios dos territórios Alto Sertão Sergipano (Nossa Senhora da Glória), Médio Sertão Sergipano (Nossa Senhora das Dores), Baixo São Francisco Sergipano (Pacatuba), Centro Sul Sergipano (Salgado), Sertão Ocidental (Tobias Barreto e Simão Dias) e Grande Aracaju (Itaporanga). As coletas foram realizadas no primeiro semestre de 2014, buscando-se coletar plantas com mesma idade de rebrote (3 a 4 meses) e em sistemas de plantio consorciado (milho e feijão), raízes e cactáceas e adensado para formação de banco de proteína para alimentação animal. O material coletado foi encaminhado ao Laboratório de Nutrição Animal da Universidade Federal de Sergipe (UFS) para a que fossem avaliadas as seguintes análises: matéria seca (MS), matéria mineral ou cinzas (MM), extrato etéreo (EE), proteína bruta (PB), fi bra em detergente neutro (FDN) e fibra em detergente ácido (FDA). As amostras foram pré- secas em estufa a 55ºC por 72 h e posteriormente moído em peneira de 1 mm em moinho tipo Willey e armazenadas à temperatura ambiente em recipientes plásticos para posteriores análises

Technical note: Influence of feed on image quality of abdominal ultrasonography in New Zealand white kits

[EN] The aim of this study was to evaluate the influence of feed change on image quality of ultrasound scanning of the gallbladder, kidney and jejunum in New Zealand White kits. Thirty-nine 35-day-old rabbits were used, distributed into 4 diet groups: C, only commercial feed; CH, commercial feed and hay; C24H, only commercial feed, replaced by hay 24 h before examination; and CH24H, commercial feed and hay, with the commercial feed withdrawn 24 h before the exam. The rabbits received the diet for 42 d (from 35 to 77 d of age) and the ultrasound evaluations were performed on days 56 and 77. Ultrasonographic assessment for image quality focused on the possibility of visualisation and an image quality rating (3 scores: unacceptable, acceptable or excellent) for the gallbladder, kidneys and jejunum. The kidneys were visualised in 100% of animals of all diets and ages. There was no difference in visualisation (P>0.05) of the gallbladder among the animals fed different diets on days 56 and 77. The C24H diet had a higher visualisation possibility (P<0.05) of the jejunum compared to the C and CH diets on day 77. For the image quality score, there was no difference in the studied organs on day 56. However, on day 77, there was a difference for the jejunum (P<0.05), and only the C24H and CH24H diets presented images classified as excellent. In conclusion, the image quality of the kidneys and gallbladder was unaffected by feed, and the jejunum had an improved image quality with the inclusion of hay and without the commercial feed 24 h before the test in New Zealand White rabbits at 77 d of age.Silva, KG.; Andrade, C.; Costa, LB.; Sotomaior, CS. (2017). Technical note: Influence of feed on image quality of abdominal ultrasonography in New Zealand white kits. World Rabbit Science. 25(4):339-343. doi:10.4995/wrs.2017.6821SWORD33934325