Federal University of Roraima

About: Federal University of Roraima is a based out in . It is known for research contribution in the topics: Population & Thermogravimetry. The organization has 981 authors who have published 1218 publications receiving 7849 citations. The organization is also known as: Federal University of Roraima.

Pyomelanin biosynthetic pathway in pigment-producer strains from the pandemic Acinetobacter baumannii IC-5.

Abstract: BACKGROUND Acinetobacter baumannii outbreaks have been associated with pandemic International Clones (ICs), but the virulence factors involved with their pathogenicity are sparsely understood. Pigment production has been linked with bacterial pathogenicity, however, this phenotype is rarely observed in A. baumannii. OBJECTIVES This study aimed to characterise the reddish-brown pigment produced by A. baumannii strains, and to determine its biosynthetic pathway by genomic approaches. METHODS Pigment characterisation and antimicrobial susceptibility were conducted by phenotypic tests. The clonal relationship was obtained by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The genome of an A. baumannii was obtained for characterisation of genes involved with pigment production. FINDINGS The pyomelanin was the pigment produced by A. baumannii. Strains were extensively drug resistant and belonged to the IC-5/ST79. The pyomelanin biosynthetic pathway was determined and presented a particular architecture concerning the peripheral (tyrB, phhB and hpd) and central (hmgB, hmgC and hmgR) metabolic pathway genes. The identification of a distant HmgA homologue, probably without dioxygenase activity, could explain pyomelanin production. Virulence determinants involved with adherence (csuA/BABCDE and a T5bSS-carrying genomic island), and iron uptake (basABCDEFGHIJ, bauABCDEF and barAB) were characterised. MAIN CONCLUSION There is a biosynthetic pathway compatible with the pyomelanin production observed in persistent A. baumannii IC-5 strains.

Stellar parameters for stars of the CoRoT exoplanet field

Abstract: Context. Spectroscopic observations represent a fundamental step in the physical characterization of stars and, in particular, in the precise location of stars in the HR diagram. Rotation is also a key parameter, impacting stellar properties and evolution, which modulates the interior and manifests itself on the surface of stars. To date, the lack of analysis based on large samples has prevented our understanding of the real impact of stellar parameters and rotation on the stellar evolution as well as on the behavior of surface abundances. The space missions, CoRoT and Kepler , are providing us with rotation periods for thousands of stars, thus enabling a robust assessment of the behavior of rotation for different populations and evolutionary stages. For these reasons, the follow-up programs are fundamental to increasing the returns of these space missions. An analysis that combines spectroscopic data and rotation/modulation periods obtained from these space missions provides the basis for establishing the evolutionary behavior of the angular momentum of solar-like stars at different evolutionary stages, and the relation of rotation with other relevant physical and chemical parameters. Aims. To support the computation and evolutionary interpretation of periods associated with the rotational modulation, oscillations, and variability of stars located in the CoRoT fields, we are conducting a spectroscopic survey for stars located in the fields already observed by the satellite. These observations allow us to compute physical and chemical parameters for our stellar sample. Methods. Using spectroscopic observations obtained with UVES/VLT and Hydra/Blanco, and based on standard analysis techniques, we computed physical and chemical parameters (T eff , log (g ), [Fe/H], v mic , v rad , v sin (i ), and A (Li)) for a large sample of CoRoT targets. Results. We provide physical and chemical parameters for a sample comprised of 138 CoRoT targets. Our analysis shows the stars in our sample are located in different evolutionary stages, ranging from the main sequence to the red giant branch, and range in spectral type from F to K. The physical and chemical properties for the stellar sample are in agreement with typical values reported for FGK stars. However, we report three stars presenting abnormal lithium behavior in the CoRoT fields. These parameters allow us to properly characterize the intrinsic properties of the stars in these fields. Our results reveal important differences in the distributions of metallicity, T eff , and evolutionary status for stars belonging to different CoRoT fields, in agreement with results obtained independently from ground-based photometric surveys. Conclusions. Our spectroscopic catalog, by providing much-needed spectroscopic information for a large sample of CoRoT targets, will be of key importance for the successful accomplishment of several different programs related to the CoRoT mission, thus it will help further boost the scientific return associated with this space mission.

Estudo cinético por TG e DSC da decomposição térmica de alguns adutos de haletos de cádmio

Abstract: By DSC data, the kinetical parameters Ea , n and A were calculated for the thermal decomposition of the adducts CdCl2.2dmf, CdCl2.dmf and CdBr2.dmf (dmf= dimethylformamide) by using Rogers and Smith method. The found values were : Ea = 85, 176 and 101 kJ mol-1 , n= 0.23, 0.25, and 0.17, A= 2.40x109, 1.89x1019 and 1.07x109 respectively. By TGA data, the kinetical patameters for the thermal decomposition of the adduct CdCl2.1,5 dmeu (dmeu=dimethylethyleneurea) were calculated by using five different methods.

Sistema internacional com hegemonia das democracias de mercado: desafios de Brasil e Argentina

Abstract: Um duro retrato da realidade internacional: esta talvez seja a frase que melhor sintetiza o livro de Eduardo Viola, professor titular de Relacoes Internacionais da Universidade de Brasilia, e Hector Ricardo Leis, professor da Universidade Federal de Santa Catarina. Apos quase vinte anos do colapso da Uniao Sovietica as transformacoes operadas no sistema internacional agora podem ser melhor percebidas: coube aos autores descreve-las de forma coerente e contundente. A linha central de pensamento dos autores e que o sistema de estados que delineia a ordem internacional vigente e baseado na hegemonia das democracias de mercado. Nesse sentido, o protagonismo norte-americano so e valido em composicao com outras grandes potencias: juntas, como democracias de mercado consolidadas, fazem da democracia seu modelo politico, do capitalismo de mercado sua moldura economica definidora e da globalizacao seu veiculo de manutencao ou transformacao da ordem vigente. Ainda que exaltando o verdadeiro liberalismo, a analise de ambos aponta para uma valorizacao do progresso social e economico como metas universais, em detrimento de orientacoes puramente ideologicas. O objetivo da obra e o de apresentar ao leitor inteligente um retrato realista da cena internacional do seculo 21, desenhada nao por incertezas e bifurcacoes, nem por antagonismos de classes e forcas sociais, mas pela certeza da preponderância do liberalismo em construir um mundo em consonância com as demandas sociais e com o objetivo de preparar as novas geracoes para lidar com a infinidade de velhos e novos desafios deste milenio, como terrorismo, pobreza e desigualdades globais, epidemias e problemas ecologicos (poluicao, desflorestamento, escassez de agua...). Para tanto, os autores dividem a obra em tres partes principais com cinco capitulos: tratam da rota de Brasil, Argentina e America do Sul rumo ao universo pos-historico das democracias de mercado. No primeiro capitulo, O sistema internacional com hegemonia das democracias de mercado no inicio do seculo XXI, os

Psicologia, política pública para a população quilombola e racismo

Abstract: This paper summarizes part of the doctoral research on quilombo Maria Rosa, one of the first rural black communities in the state of Sao Paulo to be granted a quilombola land title. The aim is to understand whether, within that community, land titling public policy operates as a mechanism to counter racism. To reach the proposed objectives, observations and interviews were carried out based on the formulations of Enrique Pichon-Riviere. Other authors such as Rene Kaes contributed to the analysis of the material. The study concluded that the policy brings those quilombo residents into contact with the effects of slavery and racism. However, they still lack an adequate support policy integrating different government levels and addressing the issue of racism.