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

Resonant x-ray scattering study on multiferroic BiMnO3

Resonant x-ray scattering is performed near the Mn K-absorption edge for an epitaxial thin film of BiMnO3. The azimuthal angle dependence of the resonant (003) peak (in monoclinic indices) is measured with different photon polarizations; for the $\sigma\to\pi'$ channel a 3-fold symmetric oscillation is observed in the intensity variation, while the $\sigma\to\sigma'$ scattering intensity remains constant. These features are accounted for in terms of the peculiar ordering of the manganese 3d orbitals in BiMnO3. It is demonstrated that the resonant peak persists up to 770 K with an anomaly around 440 K; these high and low temperatures coincide with the structural transition temperatures, seen in bulk, with and without a symmetry change, respectively. A possible relationship of the orbital order with the ferroelectricity of the system is discussed.Comment: 14 pages, 4 figure

Criticality and oscillatory behavior in non-Markovian Contact Process

A Non-Markovian generalization of one-dimensional Contact Process (CP) is being introduced in which every particle has an age and will be annihilated at its maximum age $\tau$. There is an absorbing state phase transition which is controlled by this parameter. The model can demonstrate oscillatory behavior in its approach to the stationary state. These oscillations are also present in the mean-field approximation which is a first-order differential equation with time-delay. Studying dynamical critical exponents suggests that the model belongs to the DP universlity class.Comment: 4 pages, 5 figures, to be published in Phys. Rev.

Edible coatings from galactomannans and their application to tropical fruits

Edible coatings play an important role in the quality and in the resistance to transportation, storage and display of a wide range of fresh and processed foods. Polysaccharide coatings with an oil-free appearance and low caloric content can be used to increase the shelf life of fresh fruits, since they allow the modification of the internal gas composition of fruits, retarding their senescence. The objective of this work was to study the ability of seed galactomannans, with different manose:galactose relation, from the Leguminosae Caesalpinea pulcherrima (2.8:1) and Adenanthera pavonina (2:1) as coatings to extend the shelf life of acerola (Malpighia emarginata), cajá (Spondias lutea), mango (Mangifera indica), pitanga (Eugenia uniflora) and sirigüela (Spondias purpurea). Fresh fruits surface properties, galactomannans relative viscosity as well as the wetting capacity of the coatings were determined. Galactomannans were obtained from seed endosperm and their toxicological safety was determined by oral administration to Wistar adult rats. No toxic effects were detected. Blends with different galactomannan:glycerol proportions were tested as coatings. The blends wettability was determined by the spreading coefficient using the sessile-drop method. The best proportions of galactomannan/glycerol were determined for coatings of C.pulcherrima and A.pavonina in the various fruits tested.Fundação para a Ciência e a Tecnologia (FCT) ; Alfa-Valnatura; CNPq; CAPES; FUNCAP.Alfa-Valnatur

Protein intake and obesity in schoolchildren

[resumo]Resumo de comunicação apresentada em: 16th European Congress on Obesity - ECO 2008; 2008 Mai 14-17; Genebra, Suíça

On the Formation of Copper Linear Atomic Suspended Chains

We report high resolution transmission electron microscopy and classical molecular dynamics simulation results of mechanically stretching copper nanowires conducting to linear atomic suspended chains (LACs) formation. In contrast with some previous experimental and theoretical work in literature that stated that the formation of LACs for copper should not exist our results showed the existence of LAC for the [111], [110], and [100] crystallographic directions, being thus the sequence of most probable occurence.Comment: 4 pages, 3 figure

Produção de sementes de guandu.

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Influence of Fish Capture Methods on Genotoxic Assessment in Different Tissues of Astyanax fasciatus (Osteichthyes, Characidae)

Among the approaches to evaluate genotoxicity of aquatic environments, fish are being used as biomonitors due to their sensitivity to any changes in the environment, characterizing it as sentinel organisms for the biomonitoring of rivers and lakes. Biomarkers that reflect damage to genetic material of fish are detected by the Comet Assay (EC) and through analysis of Micronucleus (MN) produced by different chemical agents and/or stressor factors due to capture, handling and keeping. Cast net and electric fishing were used for capture in this study, aiming to evaluate the influence of these methods on the analyzed biomarkers in different tissues, such as blood, gills and liver. Astyanax fasciatus (Characidae) individuals were captured in Quadros lagoon – RS, Brazil, site considered free on industrial contamination, showing a good physico-chemical quality. Results of MN test, which reflect clastogenic and aneugenic effects, presented no significant difference between the catch methods used, possibly because there was not enough time for cell division that is necessary for micronucleus forming. EC, which detects direct DNA brakeage, showed significant differences in Damage Index (ID) and Damage Percentage (%D) between capture methods in all tissues examined (p ≤ 0.001), indicating an effect of electricity on organisms collected

Moderate exercise training provides left ventricular tolerance to acute pressure overload

Moreira-Goncalves D, Henriques-Coelho T, Fonseca H, Ferreira RM, Amado F, Leite-Moreira A, Duarte JA. Moderate exercise training provides left ventricular tolerance to acute pressure overload. Am J Physiol Heart Circ Physiol 300: H1044-H1052, 2011. First published December 24, 2010; doi: 10.1152/ajpheart.01008.2010.-The present study evaluated the impact of moderate exercise training on the cardiac tolerance to acute pressure overload. Male Wistar rats were randomly submitted to exercise training or sedentary lifestyle for 14 wk. At the end of this period, the animals were anaesthetized, mechanically ventilated, and submitted to hemodynamic evaluation with biventricular tip pressure manometers. Acute pressure overload was induced by banding the descending aorta to induce a 60% increase of peak systolic left ventricular pressure during 120 min. This resulted in the following experimental groups: 1) sedentary without banding (SED + Sham), 2) sedentary with banding (SED + Band), and 3) exercise trained with banding (EX + Band). In response to aortic banding, SED + Band animals could not sustain the 60% increase of peak systolic pressure for 120 min, even with additional narrowing of the banding. This was accompanied by a reduction of dP/dt(max) and dP/dt(min) and a prolongation of the time constant tau, indicating impaired systolic and diastolic function. This impairment was not observed in EX + Band (P < 0.05 vs. SED + Band). Additionally, compared with SED + Band, EX + Band presented less myocardial damage, exhibited attenuated protein expression of active caspase-3 and NF-kappa B (P < 0.016), and showed less protein carbonylation and nitration (P < 0.05). These findings support our hypothesis that exercise training has a protective role in the modulation of the early cardiac response to pressure overload

Seleção de clones de copa de seringueira resistentes ao mal das folhas.

A fim de selecionar novos materiais genéticos para novos cultivos o trabalho teve por objetivos estimar os parâmetros genéticos de clones de copas de seringueira resistentes ao M. ulei nas condições edafoclimáticas da Amazônia Tropical Úmida, durante seis anos de produção em análise conjunta