Power-law distributions for the citation index of scientific publications and scientists

The number of citations of a scientific publication or of an individual scientist has become an important factor of quality assessment in science. We report a study of the statistical distribution of the citation index of both scientific publications and scientists. We give numerical evidence that Tsallis (power law) statistics explains the entire distribution over eight orders of magnitude (10-4 to 10(4)). Also, we draw Zipf plots in order to analyze the statistical distribution of the citation index of Brazilian and international physicists and chemists. The relatively small group of Brazilian scientists seems more adequate to explain the dynamics of the citation index. In this case, we find that the distribution of the citation index can also be explained by a gradually truncated power law with similar parameters. We finally discuss possible mechanisms behind the citation index of scientists and scientific publications.

The perception of brazilian researchers concerning the factors that influence the citation of their articles: A study in the field of sustainability

With growing institutional pressure from the Brazilian government to increase the impact of research that it funds, Brazilian researchers are increasingly interested in discovering factors that affect the citation of their articles. The aim of the present article was to assess the perceptions of Brazilian sustainability researchers to identify factors that influence the impacts of their research. A survey was conducted with researchers in the field of sustainability and 89 questionnaires were completed. All of those researchers have articles or research projects in the field of sustainability (mixing environmental, social and/or economical) recorded in the Scielo or Lattes Curriculum Brazilian databases. Results suggest four factors that may explain the impact of article citations: (1) prestige of the author and the research network; (2) prestige of the means of publication and indexing; (3) accessibility and quality characteristics of the article; and (4) international nature of communication and scope of the study. Surprisingly, such factors were not statistically significant in explaining the citations of the participating researchers. These results show the need to consider other factors that can explain the impact of research, discovering the missing links. © 2013 Elsevier Inc.

Constant Pioneers: The Citation Frontiers of Indexing Theory in the ISKO International Proceedings

Presents a citation analysis of indexing research in the two Proceedings. Understanding that there are different traditions of research into indexing, we look for evidence of this in the citing and cited authors. Three areas of cited and citing authors surface, after applying Price's elitism analysis, each roughly corresponding to geographic distributions.

Scientific knowledge and digital democracy in Brazil: how to assess public health policy debate with applied Scientometrics

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A neural system to robust Nonlinear optimization subject to disjoint and constrained sets

The ability of neural networks to realize some complex nonlinear function makes them attractive for system identification. This paper describes a novel method using artificial neural networks to solve robust parameter estimation problems for nonlinear models with unknown-but-bounded errors and uncertainties. More specifically, a modified Hopfield network is developed and its internal parameters are computed using the valid-subspace technique. These parameters guarantee the network convergence to the equilibrium points. A solution for the robust estimation problem with unknown-but-bounded error corresponds to an equilibrium point of the network. Simulation results are presented as an illustration of the proposed approach.

Mercury emissions from forest burning in southern Amazon

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relationship between visualization of meiotic spindle in human oocytes and ICSI outcomes: a meta-analysis

The objective of this meta-analysis was to investigate the influence of meiotic spindle visualization in human oocytes on intracytoplasmic sperm injection (ICSI) outcomes. Search strategies included on-line Surveys of databases (MEDLINE, em BASE, Science Citation Index, Cochrane Controlled Trials Register and Ovid). The fixed effect was used for odds ratio. Ten trials fulfilled the inclusion criteria comparing in-vitro and clinical ICSI outcomes with or without visualization of meiotic spindle in fresh and in-vivo matured oocytes. According to the meta-analysis, the results showed statistically significant higher fertilization rate (P < 0.0001) when the meiotic spindle was viewed than when it was not. Moreover, the percentage of pro-nuclear-stage embyros with good morphology (P = 0.003), cleavage rate (P < 0.0001), percentage of day-3 top-quality embryos (P = 0.003) and percentage of embryos that reached the blastocyst stage (P < 0.0001) were statistically significantly better among, embryos derived from oocytes in which meiotic spindle was viewed compared with those in which meiotic spindle was not observed. However, these differences were not observed in the clinical pregnancy or implantation rates. This observation has clinical relevance mainly in countries where there is a legal limit on the number of oocytes to be fertilized. However, additional controlled trials are needed to further confirm these results.

Identification and characterization of a potyvirus isolated from siratro plants

The present work describes the identification and characterization of a potyvirus isolated from siratro (Macroptilium atropurpureum Urb.) in the north-west region of the State of Sdo Paulo, Brazil. The virus was transmitted by mechanical inoculation. Its host range was restricted mainly to members of the Fabaceae. A cDNA fragment of about 930 bp was amplified by RT/PCR, cloned and sequenced. The fragment, which included the coat protein gene, had amino acid identity percentages between 88 and 98% with isolates of Bean common mosaic virus (BCMV). Phylogenetic analysis grouped the. siratro potyvirus and BCMV isolates in 99% of the replicates, including Azuki mosaic virus, Dendrobium mosaic virus, Blackeye cowpea mosaic virus and Peanut stripe virus, which have been classified as BCMV strains. This is the first citation on the presence of BCMV in siratro plants in Brazil.

Inflorescence and floral development of Dahlstedtia species (Leguminosae: Papilionoideae: Millettieae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

What are Scientific Leaders? The Introduction of a Normalized Impact Factor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Anatomia e ultra-estrutura foliar de Cyperus maritimus Poir. (Cyperaceae): estratégias adaptativas ao ambiente de dunas litorâneas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An intelligent system to real time rainfall prediction using radar data

This work presents a new approach for rainfall measurements making use of weather radar data for real time application to the radar systems operated by institute of Meteorological Research (IPMET) - UNESP - Bauru - SP-Brazil. Several real time adjustment techniques has been presented being most of them based on surface rain-gauge network. However, some of these methods do not regard the effect of the integration area, time integration and distance rainfall-radar. In this paper, artificial neural networks have been applied for generate a radar reflectivity-rain relationships which regard all effects described above. To evaluate prediction procedure, cross validation was performed using data from IPMET weather Doppler radar and rain-gauge network under the radar umbrella. The preliminary results were acceptable for rainfalls prediction. The small errors observed result from the spatial density and the time resolution of the rain-gauges networks used to calibrate the radar.