Orientaciones socialmente responsables para la permanencia estudiantil en programas de educación a distancia de la Universidad Industrial de Santander - UIS

Ante las dinámicas sociales del mundo actual, la educación a distancia se ha convertido en la principal estrategia orientada al aumento de capacidades y oportunidades para alcanzar niveles óptimos de bienestar social. No obstante, a pesar de programas flexibles que facilitan la vinculación universitaria como Tecnología y Gestión Empresarial, ofertados por el Instituto de Proyección Regional y Educación a Distan-cia-IPRED de la Universidad Industrial de Santander - UIS, el número de graduados en comparación con los ingresantes no es el esperado: durante el periodo 2007-2009 se identificó un índice de abandono del 55 % y 28% respectivamente. Este estudio cuantitativo de diseño descriptivo a partir de la muestra aleatoria estratificada permite la identificación de características, patrones de conducta y actitudes, para señalar los comportamientos concretos de los desertores. Como resultado, se estableció que las motivaciones socioeconómicas de abandono escolar están interconectadas con otras variables, afirmando un fenómeno multicausal que orienta a la construcción de estrategias socialmente responsables de seguimiento y permanencia, en procura de su disminución, en el marco de la Responsabilidad Social de la UIS.

In light of the social dynamics in today's world, Distance Education has become the main strategy aimed to increase capacities and opportunities, in order to achieve optimal levels of social welfare. However despite of the flexible programs that facilitate university linkage such as Technology and Business Management, offered by Instituto de Proyección Regional y Educación a Distancia - IPRED of Universidad Industrial de Santander-UIS, the number of graduates compared to the number of newcomers is not the expected: during the period of 2007-2009 it was identified a dropout index of 55% and 28% respectively. This quantitative study of descriptive design it's based in a stratified random sample, and allows the identification of characteristics, behavior patterns and attitudes, in order to indicate the specific behavior of the deserters. As a result, it was established that socioeconomic motivations of dropout are interconnected with other variables, affirming a multi-causal phenomenon that guides the construction of socially responsible strategies of monitoring and permanence, in the pursuit of its decrease, in the framework of Social Responsibility of UIS.

Dada a dinâmica social do mundo de hoje, a educação a distância se tornou a principal estratégia destinada a aumentar as capacidades e oportunidades para atingir níveis ideais de bem-estar social. No entanto, apesar dos programas flexíveis que facilitam a ligação universidade como Tecnologia e Gestão de Negócios, oferecido pelo Instituto de alcance regional e Educação a Distância-IPRED da Universidade Industrial de Santander - UIS, o número de graduados em comparação com ingresantes não se espera: durante o período de 2007-2009 uma queda do índice de 55% e 28%, respectivamente, foi identificado. Este projeto estudo descritivo quantitativo a partir de amostra aleatória estratificada permite a identificação de características, padrões de comportamento e atitudes, para indicar o comportamento específico dos desertores. Como resultado, foi estabelecido que as motivações socioeconómicas das desistências estão interligadas com outras variáveis, alegando um fenômeno multicausal que visa a construção de estratégias de monitoramento e permanência socialmente responsável, em busca de seu declínio, no âmbito da Responsabilidade Social a UIS.

Development of cell differentiation in the transition to multicellularity: a dynamical modeling approach.

Multicellularity has emerged and continues to emerge in a variety of lineages and under diverse environmental conditions. In order to attain individuality and integration, multicellular organisms must exhibit spatial cell differentiation, which in turn allows cell aggregates to robustly generate traits and behaviors at the multicellular level. Nevertheless, the mechanisms that may lead to the development of cellular differentiation and patterning in emerging multicellular organisms remain unclear. We briefly review two conceptual frameworks that have addressed this issue: the cooperation-defection framework and the dynamical patterning modules (DPMs) framework. Then, situating ourselves in the DPM formalism first put forward by S. A. Newman and collaborators, we state a hypothesis for cell differentiation and arrangement in cellular masses of emerging multicellular organisms. Our hypothesis is based on the role of the generic cell-to-cell communication and adhesion patterning mechanisms, which are two fundamental mechanisms for the evolution of multicellularity, and whose molecules seem to be well-conserved in extant multicellular organisms and their unicellular relatives. We review some fundamental ideas underlying this hypothesis and contrast them with empirical and theoretical evidence currently available. Next, we use a mathematical model to illustrate how the mechanisms and assumptions considered in the hypothesis we postulate may render stereotypical arrangements of differentiated cells in an emerging cellular aggregate and may contribute to the variation and recreation of multicellular phenotypes. Finally, we discuss the potential implications of our approach and compare them to those entailed by the cooperation-defection framework in the study of cell differentiation in the transition to multicellularity.

Influence of occlusal contact area on cusp defection and stress distribution.

OBJECTIVE: The purpose of this study was to evaluate the effect of occlusal contact area for loading on the cuspal defection and stress distribution in a first premolar restored with a high elastic modulus restorative material. MATERIALS AND METHODS: The Rhinoceros 4.0 software was used for modeling the three-dimensional geometries of dental and periodontal structures and the inlay restoration. Thus, two different models, intact and restored teeth with three occlusal contact areas, 0.1, 0.5 and 0.75 mm(2), on enamel at the occlusal surface of buccal and lingual cusps. Finite element analysis (FEA) was performed with the program ANSYS (Workbench 13.0), which generated a mesh with tetrahedral elements with greater refinement in the regions of interest, and was constrained at the bases of cortical and trabecular bone in all axis and loaded with 100 N normal to each contact area. RESULTS: To analysis of maximum principal stress, the smaller occlusal contact area showed greater compressive stress in region of load application for both the intact and inlay restored tooth. However, tensile stresses at the occlusal isthmus were similar for all three tested occlusal contact areas (60 MPa). To displacement of the cusps was higher for teeth with inlay (0.46-0.48 mm). For intact teeth, the smaller contact area showed greater displacement (0.10 mm). For teeth with inlays, the displacement of the cusps were similar in all types of occlusal area. CONCLUSION: Cuspal displacement was higher in the restored tooth when compared to the intact tooth, but there were no significant variations even with changes in the occlusal contact area. RELEVANCE CLINICAL: Occlusal contacts have a great influence on the positioning of teeth being able to maintain the position and stability of the mandible. Axial loads would be able to generate more uniform stress at the root presenting a greater concentration of load application in the point and the occlusal surface. Thus, is necessary to analyze the relationship between these occlusal contacts as dental wear and subsequent occlusal interferences.

Cuspal deflection of directly or indirectly restored teeth / Deflexão cuspídea de dentes restaurados direta ou indiretamente

Objective: The aim of this study was to evaluate the cuspal deflection of teeth restored directly and indirectly. Material and Methods: Forty sound maxillary premolar teeth were restored with composite and different base materials. Wide mesial-occlusal-distal cavity preparations were performed, with isthmus width of one third of the distance between the cuspal tips, 3 mm occlusal and a 5 mm interproximal preparation height. The teeth were divided into 4 groups (n = 10), according to the restoration type: G1) GIC-DCR (1 mm glass ionomer cement base and direct restoration using nanoparticulate composite); G2) FL-DCR (1 mm base of flowable composite resin and direct restoration using nanoparticulate composite); G3) GIC-ICR (1 mm glass ionomer cement base and indirect restoration using nanoparticulate composite GIC base); G4) FL-ICR (1 mm base of flowable composite resin and indirect restoration using nanoparticulate composite). The specimens were submitted to compressive load of 50 N on the buccal and lingual cusps, in a universal testing machine. The lingual cusp microstrain (με) measurements were executed by strain gauges. Results: The Kruskal-Wallis (5%) test was used and showed there were no significant differences among the microstrain values for the four study groups (G1 = 1250; G2 = 1075; G3 = 1279; G4 = 937). Conclusion: It could be concluded that the restorative techniques and the bases employed did not show any influences in cuspal deflection

Objetivo: O objetivo deste trabalho foi avaliar, por meio de medidores de tensão, a deflexão cuspídea sofrida por dentes restaurados, direta e indiretamente, com resinas compostas e diferentes materiais de base. Material e Métodos: Para o preparo dos corpos-de-prova (CP) foram utilizados 28 dentes pré-molares humanos íntegros, extraídos por razões ortodônticas que tiveram suas raízes embutidas em poliuretano de densidade semelhante a do osso e suas raízes recobertas por um espaçador visando simular o espaço referente ao ligamento periodontal. Na etapa seguinte os dentes receberam preparos cavitários do tipo mésio-ocluso-distais amplos e então restaurados direta e indiretamente com resina composta e dois diferentes materiais de base/forramento, resina flow e cimento de ionômero de vidro. Para a realização das medidas de deflexão das cúspides foram utilizados extensômetros lineares elétricos colados à face lingual de cada dente e submetidos a uma carga de 50 N aplicada por uma ponta romba de diâmetro de 3,0 mm, que promoveu compressão simultânea nas vertentes triturantes das cúspides vestibular e lingual, numa máquina universal de ensaios. Resultados: Foi realizado o teste de Kruskall-Wallis (5%) de significância e não foram encontradas diferenças estatísticamente significantes entre os grupos (G1 – 1250; G2 = 1075; G3 = 1279; G4 = 937). Conclusão: Pode-se concluir que o tipo de restauração bem como o tipo de base empregados nesse estudo não alteram a deflexão cuspídea dos dentes com restaurações amplas.

Ocorrência de diferentes tipos de canais acessórios cavo inter-radiculares em molares de humanos. Estudo histológico / Ocurrence of different types of cavo inter-radicular accessory canals in human molars. A histologic study

Apesar de haver muitos estudos que mostrem a prevalência e o diâmetro dos canais acessórios na região de furca, há escassez de trabalhos que observem o trajeto e os diferentes tipos de canais cavo inter-radiculares. Assim, o objetivo de nosso estudo foi verificar a ocorrência dos diferentes tipos morfológicos de canais acessórios na região de furca, na tentativa de mostrar os seus trajetos, através de cortes histológicos em molares de humanos. Foram utilizados 40 terceiros molares inferiores inclusos com separação radicular, os quais foram extraídos e descalcificados para a realização de microtomia no plano axial mésio-distal, obtendo-se cortes semi-seriados com espessura de 5µm. Os cortes foram corados com Hematoxilina e Eosina e observados em microscopia ótica em 40X, 100X, 200X e 400X. Os resultados mostraram que todos os tipos morfológicos foram encontrados, sendo que os canais acessórios verdadeiros, do tipo A estavam presentes em 10% dos espécimes. Os canais mais prevalentes foram os microcanais do tipo E, com prevalência de 100%, seguidos pelos fechados do tipo D com 87,5%, e pelos cegos do tipo B, com 75%. Os canais acessórios em alça, do tipo C, foram observados em apenas 5% dos dentes, sendo os menos prevalentes

Although there are several studies that show prevalence and diameter of accessory root canals in the furcation area, there is a scarceness of studies which observe the trajectory and different types of cavo inter-radicular canals. The objective of the present study was to verify the occurrence of different morphologic types of accessory root canals in the furcation area, in an attempt to show their trajectories, through histological sections in human molar teeth. Forty unerupted mandibular third molar teeth with radicular separation were used. They were extracted and decalcified so that microtomy could be performed towards mesio-distal axial plane, obtaining semi-serial sections with thickness of 5µm. The sections were stained with Hematoxylin and Eosin, and were observed under optical microscopy at 40X, 100X, 200X and 400X magnifications. The results showed that all morphologic types were found; the real accessory canals, type A, were present in 10% of the specimens. The most prevalent canals were type-E microcanals, with prevalence of 100%, followed by sealed type-D canals, with 87.5%, and by blind type-B canals, with 75%. The loop type-C accessory canals were observed in only 5% of the teeth, and were the least prevalent