The Oligocene-Neogene deep-sea Columbia Channel system in the South Brazilian Basin: Seismic stratigraphy and environmental changes

The Columbia Channel (CCS) system is a depositional system located in the South Brazilian Basin, south of the Vitoria-Trindade volcanic chain. It lies in a WNW-ESE direction on the continental rise and abyssal plain, at a depth of between 4200 and 5200 m. It is formed by two depocenters elongated respectively south and north of the channel that show different sediment patterns. The area is swept by a deep western boundary current formed by AABW. The system has been previously interpreted has a mixed turbidite-contourite system. More detailed study of seismic data permits a more precise definition of the modern channel morphology, the system stratigraphy as well as the sedimentary processes and control. The modern CCS presents active erosion and/or transport along the channel. The ancient Oligo-Neogene system overlies a ""upper Cretaceous-Paleogene"" sedimentary substratum (Unit U1) bounded at the top by a major erosive ""late Eocene-early Oligocene"" discordance (D2). This ancient system is subdivided into 2 seismic units (U2 and U3). The thick basal U2 unit constitutes the larger part of the system. It consists of three subunits bounded by unconformities: D3 (""Oligocene-Miocene boundary""), D4 (""late Miocene"") and D5 (""late Pliocene""). The subunits have a fairly tabular geometry in the shallow NW depocenter associated with predominant turbidite deposits. They present a mounded shape in the deep NE depocenter, and are interpreted as forming a contourite drift. South of the channel, the deposits are interpreted as a contourite sheet drift. The surficial U3 unit forms a thin carpet of deposits. The beginning of the channel occurs at the end of U1 and during the formation of D2. Its location seems to have been determined by active faults. The channel has been active throughout the late Oligocene and Neogene and its depth increased continuously as a consequence of erosion of the channel floor and deposit aggradation along its margins. Such a mixed turbidite-contourite system (or fan drift) is characterized by frequent, rapid lateral facies variations and by unconformities that cross the whole system and are associated with increased AABW circulation. (C) 2009 Elsevier B.V. All rights reserved.

Describing the Situational Contexts of Sweetened Product Consumption in a Middle Eastern Canadian Community: Application of a Mixed Method Design

Little is known about the situational contexts in which individuals consume processed sources of dietary sugars. This study aimed to describe the situational contexts associated with the consumption of sweetened food and drink products in a Catholic Middle Eastern Canadian community. A two-stage exploratory sequential mixed-method design was employed with a rationale of triangulation. In stage 1 (n = 62), items and themes describing the situational contexts of sweetened food and drink product consumption were identified from semi-structured interviews and were used to develop the content for the Situational Context Instrument for Sweetened Product Consumption (SCISPC). Face validity, readability and cultural relevance of the instrument were assessed. In stage 2 (n = 192), a cross-sectional study was conducted and exploratory factor analysis was used to examine the structure of themes that emerged from the qualitative analysis as a means of furthering construct validation. The SCISPC reliability and predictive validity on the daily consumption of sweetened products were also assessed. In stage 1, six themes and 40-items describing the situational contexts of sweetened product consumption emerged from the qualitative analysis and were used to construct the first draft of the SCISPC. In stage 2, factor analysis enabled the clarification and/or expansion of the instrument's initial thematic structure. The revised SCISPC has seven factors and 31 items describing the situational contexts of sweetened product consumption. Initial validation of the instrument indicated it has excellent internal consistency and adequate test-retest reliability. Two factors of the SCISPC had predictive validity for the daily consumption of total sugar from sweetened products (Snacking and Energy demands) while the other factors (Socialization, Indulgence, Constraints, Visual Stimuli and Emotional needs) were rather associated to occasional consumption of these products.

Correlating phase and microstructure development versus dielectric properties in La3+ and Er3+ co-doped Bi4Ti3O12 ferroelectric ceramics

Bi3.25La0.75-xErxTi3O12 and Bi3.25La0.75Ti3-xErxO12-delta ceramics were prepared and studied in this work in terms of dopant-induced phase and microstructure development as well as dielectric response. The results show that introduction of Er3+ tends to reduce the materials' sintering temperature and average grain size. Moreover, it was noted that in these systems the substitution site of this dopant is controlled by valence state and ionic radii mismatch effects. In particular, even when a nominal substitution of Ti4+ is conceived, here it is found that Er3+ also incorporates at the (Bi,La)(3+) sites. These and other interesting concluding remarks from this work, including Er3+ tolerance, were possible only after comparing, especially, the X-ray diffraction results and the intrinsic ferroelectric characteristics extracted from the dielectric measurements. (C) 2011 Elsevier B.V. All rights reserved.

Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome.

Linking origin of the electric field-assisted beta-PbF2 crystallization in lead oxyfluoroborate glasses below T (g) to simultaneous cathode/anode-compensated electrochemical reactions

Full validation of the electrochemical mechanisms so far postulated as driving force of electric field-assisted non-spontaneous crystallization development in given glasses has suffered experimental restrictions. In this work, we looked into origin of this phenomenon in lead oxyfluoroborate glasses, resulting in beta-PbF2 growth even below the corresponding glass transition temperatures, through achieving a systematic study of not only Pt,Ag/Glass/Ag,Pt- but also Pt,Ag/Glass/YSZ:PbF2/Ag,Pt-type cells, where YSZ:PbF2 represents a two-phase system (formed by Y2O3-doped ZrO2 and PbF2). It is demonstrated that crystallization induction in these glasses involves Pb2+ ions reduction at the cathode, the phenomenon being, however, confirmed only when the F- ions were simultaneously also able to reach the anode for oxidation, after assuring either a direct glass-anode contact or percolation pathways for free fluoride migration across the YSZ:PbF2 mixtures. A further support of this account is that the electrochemically induced beta-PbF2 phase crystallizes showing ramified-like microstructure morphology that arises, accordingly, from development of electroconvective diffusion processes under electric field action.

Effect of pH-induced nanopowder deagglomeration on sintering, microstructure and dielectric properties of Ba0.77Ca0.23TiO3 ceramics

Ba0.77Ca0.23TiO3 ceramics were produced in this work starting from nanopowders synthesized via a polymeric precursor method. By adjusting the pH values of the precursor solutions above 7, it was possible to prepare powders weakly aggregated and with a smaller particle size, both facts which traduced into an enhanced nanopowders' sintering process at comparatively lower temperatures. Irrespective of the initial pH value, highly-dense and second phase-free ceramics were obtained following optimal sintering parameters (temperature and time) extracted from dilatometric and density measurements. By considering these and other sintering conditions, moreover, polycrystalline materials with an average grain size varying from 0.35 to 8 mm were produced, the grain growth process involving liquid phase-assisted sintering for heat treatments achieved at 1320 °C. The study of grain size effects on the ferroelectric properties of these materials was conducted, the results being discussed in the light of previous debates, including grain size-dependent degree of tetragonal distortion in such materials, as verified in this work.

Acessibilidade e visibilidade de revistas científicas eletrônicas

Prefácio Antonio Miranda Apresentação Sueli Mara Soares Pinto Ferreira e Maria das Graças Targino PARTE I: COMO GARANTIR ACESSIBILIDADE DA PRODUÇÃO CIENTÍFICA Acesso Aberto e divisão entre ciência predominante e ciência periférica Jean-Claude Guédon Motivação para publicar em revistas científicas: estudo nas áreas de ciências da comunicação e ciência da informação Sueli Mara Soares Pinto Ferreira, Patrícia Zeni Marchiori e Fulvio Cristofoli Percepção sobre acesso e visibilidade dos repositórios digitais e das revistas eletrônicas Simone da Rocha Weitzel e Sueli Mara Soares Pinto Ferreira PARTE II: COMO PROMOVER E MEDIR MAIOR DISSEMINAÇÃO E VISIBILIDADE DA PRODUÇÃO CIENTÍFICA Indicadores web e sua aplicação à produção científica disponibilizada em revistas eletrônicas Nadia Vanti Limites e potencialidades da avaliação científica: crítica epistemológica à cobertura de bases de dados e à construção de indicadores Eduardo Aguado-López, Rosario Rogel-Salazar e Arianna Becerril-García Como usar – e se beneficiar – do formato RSS (Really Simple Syndication) para disseminação de informações em revistas científicas eletrônicas Robson Lopes de Almeida Métricas alternativas de avaliação do impacto e do uso de revistas eletrônicas: estudo em ciências da comunicação.

Em busca de novas métricas de avaliação da produção científica em ciências da comunicação

A busca da comunidade científica por melhores posições e maiores reconhecimentos, junto a sociedade científica e agências de fomento nacionais e internacionais, sempre esteve atrelada ao sistema de avaliação de sua produção. Portanto, conhecer os fluxos da comunicação científica, desvendar os mecanismos existentes para a qualificação da ciência e implementar mecanismos e ferramentas para a obtenção de indicadores e parâmetros que possibilitem o mapeamento por áreas específicas do conhecimento, tem sido foco de estudos já há muito tempo. Como resultados surgem dois movimentos internacionais: Open Archives Initiative (OAI) e Open Access (OA), ambos oferecendo maiores e distintas oportunidades de se revisar os atuais critérios de qualidade. Observando-se especificamente a área das ciências da comunicação brasileira, várias indagações se tornam relevantes: Qual o impacto da produção científica brasileira da área de Ciências da Comunicação? Quais mecanismos de medição estão disponíveis nesta área e como tem sido feita a avaliação desta produção brasileira pela comunidade científica nacional e internacional? O que tem sido feito para melhoria da área em termos nacionais? Como garantir a visibilidade e a acessibilidade desta produção e ainda possibilitar a produção de novos indicadores bibliométricos e infométricos? Quais serviços se encontram disponíveis hoje e como se apresentam seus resultados? Este artigo visa trazer uma discussão epistemológica sobre o modelo internacional de avaliação da produção científica adotado pelo Brasil, de modo a contextualizar e problematizar a situação específica de uma subárea das ciências sociais aplicadas, qual seja a ciências da comunicação, e buscar novas opções em relação a indicadores e métricas de avaliação da produção científica da área. Para tanto, sumariza as principais idéias e pontos relevantes para responder cada uma das questões básicas enunciadas anteriormente, evidencia algumas das possibilidades e iniciativas disponíveis hoje em distintos países e aponta iniciativas brasileiras que buscam incluir a área de ciências da comunicação brasileira no contexto científico nacional e internacional.