Análise bibliométrica de revistas veterinárias multilíngues

Indexación: Scopus; Scielo.The purpose of this study was to investigate the association between language and total number of citations found among documents in journals written in English and other languages. We selected all the journals clustered together in the Journal Citation Reports 2014 under the subject category "Veterinary Sciences" and downloaded all the data registered between 1994-2013 by Web of Science for the journals that stated publishing documents in languages other than English. We classified each of these journals by quartile and extracted information regarding their impact factor, language(s) stated, country of origin, total number of documents published, total number of reviews published, percentage of documents published in English and the quartile in which each journal ranked. Of the 48,118 documents published by the 28 journals analyzed, 55.8% were published in English. Interestingly, although most of the journals state being multi-language, most documents published in quartile 1 journals were in English (an average of 99.2%), while the percentage was 93.1% in quartile 2 journals, 62.1% in quartile 3 journals and 27.4% in quartile 4 journals. We also confirmed that citation distribution in these journals was highly skewed. The results of this study suggest that journals should consider adopting English as the main language as this will increase citation counts and the impact factor of the journal.O objetivo deste estudo foi investigar a associação entre a escolha do idioma e o número de citações, a partir da análise de revistas publicadas em inglês e em outras línguas. Foram selecionadas as revistas agrupadas no Journal Citation Reports de 2014 sob a categoria “ciências veterinárias”, bem como os dados registrados na Web of Science entre 1994 e 2013 sobre as revistas que declararam documentos publicados em outro idioma que não o inglês. A seguir, as revistas foram classificadas por quartil, extraindo-se informações acerca de: índice de impacto, idioma(s) declarado(s), país de origem, número total de documentos publicados, número total de revisões publicadas, porcentagem de documentos publicados em inglês e quartil em que cada jornal foi classificado. Dos 48.118 documentos editados por 28 revistas analisadas, 55,8% foram publicados em inglês. Interessantemente, apesar de a maioria dessas revistas se declarar multilíngue, a maior parte dos documentos publicados em revistas quartil 1 empregou o inglês (uma média de 99,2%), enquanto para as revistas quartil 2 esse índice foi de 93,1%, para quartil 3 foi de 62,1%, e para quartil 4 foi de 27,4%. A pesquisa também confirmou que a distribuição das citações nessas revistas foi altamente distorcida. Os resultados do estudo sugerem que as revistas deveriam adotar o inglês como idioma principal, o que faz aumentar o número de citações e o fator de impacto da revista.http://ref.scielo.org/zzbf6

The role of natural variability in projections of climate change impacts on U.S. ozone pollution

Climate change can impact air quality by altering the atmospheric conditions that determine pollutant concentrations. Over large regions of the U.S., projected changes in climate are expected to favor formation of ground-level ozone and aggravate associated health effects. However, modeling studies exploring air quality-climate interactions have often overlooked the role of natural variability, a major source of uncertainty in projections. Here we use the largest ensemble simulation of climate-induced changes in air quality generated to date to assess its influence on estimates of climate change impacts on U.S. ozone. We find that natural variability can significantly alter the robustness of projections of the future climate's effect on ozone pollution. In this study, a 15 year simulation length minimum is required to identify a distinct anthropogenic-forced signal. Therefore, we suggest that studies assessing air quality impacts use multidecadal simulations or initial condition ensembles. With natural variability, impacts attributable to climate may be difficult to discern before midcentury or under stabilization scenarios

Natural Variability in Projections of Climate Change Impacts on Fine Particulate Matter Pollution

Variations in meteorology associated with climate change can impact fine particulate matter (PM2.5) pollution by affecting natural emissions, atmospheric chemistry, and pollutant transport. However, substantial discrepancies exist among model-based projections of PM2.5 impacts driven by anthropogenic climate change. Natural variability can significantly contribute to the uncertainty in these estimates. Using a large ensemble of climate and atmospheric chemistry simulations, we evaluate the influence of natural variability on projections of climate change impacts on PM2.5 pollution in the United States. We find that natural variability in simulated PM2.5 can be comparable or larger than reported estimates of anthropogenic-induced climate impacts. Relative to mean concentrations, the variability in projected PM2.5 climate impacts can also exceed that of ozone impacts. Based on our projections, we recommend that analyses aiming to isolate the effect climate change on PM2.5 use 10 years or more of modeling to capture the internal variability in air quality and increase confidence that the anthropogenic-forced effect is differentiated from the noise introduced by natural variability. Projections at a regional scale or under greenhouse gas mitigation scenarios can require additional modeling to attribute impacts to climate change. Adequately considering natural variability can be an important step toward explaining the inconsistencies in estimates of climate-induced impacts on PM2.5. Improved treatment of natural variability through extended modeling lengths or initial condition ensembles can reduce uncertainty in air quality projections and improve assessments of climate policy risks and benefits

Exact and approximate symmetries for light propagation equations with higher order nonlinearity

For the first time exact analytical solutions to the eikonal equations in (1+1) dimensions with a refractive index being a saturated function of intensity are constructed. It is demonstrated that the solutions exhibit collapse; an explicit analytical expression for the self-focusing position, where the intensity tends to infinity, is found. Based on an approximated Lie symmetry group, solutions to the eikonal equations with arbitrary nonlinear refractive index are constructed. Comparison between exact and approximate solutions is presented. Approximate solutions to the nonlinear Schrodinger equation in (1+2) dimensions with arbitrary refractive index and initial intensity distribution are obtained. A particular case of refractive index consisting of Kerr refraction and multiphoton ionization is considered. It is demonstrated that the beam collapse can take place not only at the beam axis but also in an off-axis ring region around it. An analytical condition distinguishing these two cases is obtained and explicit formula for the self-focusing position is presented.Comment: 25 pages, 5 figure

Semiempirical Modeling of Reset Transitions in Unipolar Resistive-Switching based Memristors

We have measured the transition process from the high to low resistivity states, i.e., the reset process of resistive switching based memristors based on Ni/HfO2/Si-n+ structures, and have also developed an analytical model for their electrical characteristics. When the characteristic curves are plotted in the current-voltage (I-V) domain a high variability is observed. In spite of that, when the same curves are plotted in the charge-flux domain (Q-phi), they can be described by a simple model containing only three parameters: the charge (Qrst) and the flux (rst) at the reset point, and an exponent, n, relating the charge and the flux before the reset transition. The three parameters can be easily extracted from the Q-phi plots. There is a strong correlation between these three parameters, the origin of which is still under study