Browsing by Issue Date, starting with "2008-07"
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- The effects of innovation on vertical structure: perspectives on transaction costs and competencesPublication . Wolter, Claudio; Veloso, Francisco M.We analyze how transaction cost economics and competence arguments determine vertical organization boundaries when firms react to innovation. Existing perspectives and empirical evidence have been ambiguous because of conflicting tensions between the two frameworks and simplistic views of innovation. Using Henderson and Clark's (1990) innovation categories and a careful review of both theories, we show that it is possible to reach a consistent set of predictions on vertical integration and to reconcile apparently conflicting empirical results.
- O discurso histórico sobre o serviço social: uma perspectiva analítica sobre o quadro de produção científica em Portugal (1987-2007)Publication . Santos, Maria IsabelO trabalho desenvolvido constitui um estudo exploratório acerca do discurso histórico sobre o Serviço Social em Portugal, a partir do quadro de produção científica nacional, entre 1987 e 2007. O discurso em causa (modo de escrita e reflexão sobre a história) não resulta do trabalho produzido pelos historiadores em geral, mas de estudos desenvolvidos por assistentes sociais que indagaram historicamente a sua profissão. O estudo realizado permitiu evidenciar a necessidade de estabilizar um quadro teórico de referência sobre a natureza do Serviço Social, levando-nos a questionar se a própria história do Serviço Social não poderá carrilar elementos para o aprofundamento desta reflexão.
- Instrumental and sensory approaches for the characterization of compounds responsible for wine aromaPublication . Barbe, Jean-Christophe; Pineau, Bénédicte; Ferreira, Antonio Cesar SilvaMore than 800 aromatic compounds have been identified in wine, some of them at the ng/l level. Wine, therefore, constitutes a very complex matrix, from which it is difficult to isolate a specific aroma character. Gas chromatography–olfactometry (GC–O) applied to wine extracts is used to characterize odor-active zones that are often treated in a hierarchical way by Aroma Extract Dilution Analysis (AEDA). The aromatic impact of the volatiles is evaluated, generally by determining perception thresholds. This methodology has provided convincing results concerning wine flavors, but it does have its limitations. Forinstance , data on b-damascenone have demonstrated that these methods could reach their limits for this volatile, in particular, because of the non-quantitative representation of aroma extracts of wines, and because of the difficulty to accurately determine the perception threshold in wines for a compound already present. For b-damascenone, we have shown that its very low detection threshold with GC–O, its wide range, and its dependence on the composition of the medium resulted in overestimating its direct impact on the aroma of wine. Another way to facilitate the characterization of aromatic compounds was, therefore, investigated. High-Performance Liquid Chromatography (HPLC) methods were developed for the analysis of wine extracts. From an aromatic extract, 25 fractions with various flavors were thus obtained, and reverse-phase methodology was used for the selection and characterization of red- and black-fruit aromas in red wines.
- Effect of phenolic aldehydes and flavonoids on growth and inactivation of Oenococcus oeni and Lactobacillus hilgardiiPublication . Figueiredo, Ana Rita; Campos, Francisco; Freitas, Víctor de; Hogg, Tim; Couto, José AntónioThe aim of this work was to investigate the effect of wine phenolic aldehydes, flavonoids and tannins on growth and viability of strains of Oenococcus oeni and Lactobacillus hilgardii. Cultures were grown in ethanol-containing MRS/TJ medium supplemented with different concentrations of phenolic aldehydes or flavonoids and monitored spectrophotometrically. The effect of tannins was evaluated by monitoring the progressive inactivation of cells in ethanol-containing phosphate buffer supplemented with grape seed extracts with different molecular weight tannins. Of the phenolic aldehydes tested, sinapaldehyde, coniferaldehyde, p-hydroxybenzaldehyde, 3,4- dihydroxybenzaldehyde and 3,4,5-trihydroxybenzaldehyde significantly inhibited the growth of O. oeni VF, while vanillin and syringaldehyde had no effect at the concentrations tested. Lact. hilgardii 5 was only inhibited by sinapaldehyde and coniferaldehyde. Among the flavonoids, quercetin and kaempferol exerted an inhibitory effect especially on O. oeni VF. Myricetin and the flavan-3-ols studied (catechin and epicatechin) did not affect considerably the growth of both strains. Condensed tannins (particularly tetramers and pentamers) were found to strongly affect cell viability, especially in the case of O. oeni VF. In general, this strain was found to be more sensitive than Lact. hilgardii 5 to the phenolic compounds studied. This work contributes to the knowledge of the effect of different phenolic compounds on the activity of wine lactic acid bacteria, which, especially in the case of aldehydes and of different molecular weight fractions of tannins, is very scarce.
- Informática dentária: uma disciplina emergentePublication . Correia, André Ricardo Maia; Matos, César Ricardo Coimbra de; Pinto, Ana Lúcia Matos; Filipe, Magda Joana Marques; Costa, Patrícia Margarida F. VasconcelosEste trabalho de revisão de literatura pretende demonstrar não só a importância da introdução da disciplina de Informática Odontológica no currículo das Faculdades de Odontologia mas também no cotidiano do médico-dentista ou cirurgião-dentista. Nos últimos anos houve um rápido desenvolvimento da Informática aplicada à Odontologia, sobretudo em áreas dedicadas ao exame do paciente, ao diagnóstico e ao plano de tratamento. Os sistemas CAD-CAM, as sondas periodontais computadorizadas, os aparelhos de radiologia digital, as câmaras intra-orais são exemplos da aplicação da Informática em Odontologia. É neste sentido que surge a disciplina de Informática Odontológica, uma área em constante desenvolvimento, que tem por base a aplicação de computadores e ciências de informação para melhorar a prática clínica, a pesquisa, a educação e a gestão. É importante que simultaneamente com a formação em Odontologia haja também adequada formação em Informática Odontológica. Atualmente os avanços tecnológicos e as pesquisas científicas requerem interdisciplinaridade e integração de uma grande quantidade de informação, muitas vezes proveniente de fontes díspares, havendo necessidade de compilar a informação em bases de dados. Os meios informáticos podem aumentar significativamente a velocidade de integração e correlação dessa informação, tornando o diagnóstico médico-odontológico mais rápido e a implementação da terapêutica mais eficaz. Palavras-chave: Informática Odontológica; bioinformática; base de dados; formação odontológica; diagnóstico