Universidade Positivo

About: Universidade Positivo is a education organization based out in Curitiba, Brazil. It is known for research contribution in the topics: Population & Biodiversity. The organization has 1290 authors who have published 1237 publications receiving 9335 citations. The organization is also known as: Positive University.

Thermoanalytical study and characterization of native starches of Paraná pine seeds (Araucaria angustiofolia, Bert O. Ktze) and European chestnut seeds (Castanea sativa, Mill)

Abstract: Starch is the most important carbohydrate storage in plants. It is a raw material with diverse botanical origins, and is used by the food, paper, chemical, pharmaceutical, textile and other industries. In this work, native starches of Parana pine seeds (pinhao) (Araucaria angustiofolia, Bert O. Ktze) and european chestnut seeds (Castanea sativa, Mill) were studied by thermoanalytical techniques: thermo-gravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC), as well as X-ray powder patterns diffractometry. Apparent and total amylose content was also determined.

Gestão de operações no Brasil: uma análise do campo científico a partir da rede social de pesquisadores

Abstract: Este estudo analisa a rede de pesquisadores que publicam no campo de Gestao de Operacoes no Brasil, baseando-se em 2.668 artigos publicados entre 1997 a 2009. As hipoteses do estudo sao referenciadas na literatura de redes sociais e de avaliacao de campos cientificos. Os resultados apontam que, apesar da existencia de uma rede fragmentada e pouco densa, ha grupos coesos e proximos que dao estabilidade ao campo (redes small worlds). Verificou-se que o numero de lacos do pesquisador (centralidade de grau) esta positivamente associado ao numero de artigos publicados, embora afete negativamente sua produtividade. Quando consideramos os lacos nao redundantes (structural holes), os resultados se mostraram positivos e significativos tanto para a producao quanto para a produtividade. Ademais, observou-se ainda que a centralidade do pesquisador modera o efeito dos lacos nao redundantes, sendo seu efeito sobre a produtividade maior entre pesquisadores com maior grau de centralidade.

The role and contributions of sociological institutional theory to the socio-technical approach to innovation theory

Abstract: This study seeks to broaden the analytical scope of the socio-technical approach to innovation theory through the incorporation of a few theoretical constructs from sociological institutional theory This work is relevant due to its linking of these two theories which have points in common in the explanation of the variables and phenomena that they study, such as the possibility that innovation is diffused through the institutional bases and legitimacy of Institutional Theory, as well as the fact that the relationships between system actors can influence these results This study uses a narrative literature review to compare these two theories and presents a significant result in applying contributions from institutional theory to the theory of innovation

Effect of different bleaching protocols on whitening efficiency and enamel superficial microhardness.

Abstract: Background Tooth bleaching is a popular aesthetic treatment to modify the color of teeth. Despite the extensive literature concerning the subject, there is still no consensus regarding the application mode of the different bleaching agents and their effect on enamel. Therefore, this study evaluated the influence of different bleaching protocols on whitening efficiency and enamel superficial hardness. Material and methods Bovine enamel fragments were embedded in acrylic resin and wet-sanded to obtain a flat buccal surface. The specimens were then randomly divided into 6 groups (n=10), based on the bleaching material [HP Maxx 35% (35% hydrogen peroxide), HP Blue 35% (35% hydrogen peroxide + Ca) and Whiteness Perfect 10% (10% carbamide peroxide)] and application mode (3 applications of 15 min, 1 application of 45 min, 1 application of 1h30 or 1 application of 3h30). The color and superficial hardness were assessed before and after bleaching. The color was assessed by means of a digital spectrophotometer, using CIELab parameters. Vickers hardness was determined using a load of 200g for 10s. Data were statistically analyzed by one-way ANOVA with repeated measures and Tukey's test (α = 0.05). Results Concerning the color alteration, the groups were similar to each other, except for at-home bleaching protocols, which were statistically different from each other. Similarly, there was a reduction in hardness values comparing the initial and final periods, with lowest final hardness for the at-home bleaching protocol group applied for 3h30. Conclusions It can be concluded that the bleaching protocols influenced the final color and enamel surface hardness, evidencing that lower gel concentrations applied for longer periods promoted greater variation in color and lower final hardness. Key words:Tooth bleaching, roughness, microhardness, in-office, at-home bleaching.