Estudio comparativo de microfiltración marginal en restauraciones de composite, utilizando diferentes adhesivos de 5ta generación

Tesis (Cirujano Dentista, Especialización en Clínica Integral del Adulto)Objetivo: Comparar el grado de microfiltracion marginal de restauraciones de composite clase II, utilizando diferentes sistemas de adhesivos de quinta generacion. - Materiales y métodos: Se seleccionaron 30 premolares superiores e inferiores, extraídos por indicación ortodóncica en el CESFAM Dr. Luis Ferrada de Maipú, a los cuales se les realizó cavidades clase ll en su cara mesial y distal. Se dividió la muestra aleatoriamente en 3 grupos de 10. Se obturaron las cavidades con resina Filtek Z250 3M, utilizando 3 sistemas adhesivos diferentes de 5ta generación. Se realizó termociclado de las piezas restauradas, luego tinción con fucsina básica 1% por 24 hrs y finalmente se cortó axialmentecorte cada corona para analizar el grado de microfiltración marginal. El análisis estadístico se realizó con el test de Kruskal-Wallis. - Resultados: Se obtuvo un valor de P= 0,210 lo que significa que no hubo diferencias estadísticamente significativas entre los grupos. - Conclusión: Se acepta la hipótesis planteada,´´No existen diferencias significativas en el grado de microfiltración marginal de restauraciones de composite realizadas con diferentes sistemas de adhesivos de quinta generación´´

A fuzzy approach to construction project risk assessment

The increasing complexity and dynamism of construction projects have imposed substantial uncertainties and subjectivities in the risk analysis process. Most of the real-world risk analysis problems contain a mixture of quantitative and qualitative data; therefore quantitative risk assessment techniques are inadequate for prioritizing risks. This article presents a risk assessment methodology based on the Fuzzy Sets Theory, which is an effective tool to deal with subjective judgement, and on the Analytic Hierarchy Process (AHP), which is used to structure a large number of risks. The proposed methodology incorporates knowledge and experience acquired from many experts, since they carry out the risks identification and their structuring, and also the subjective judgements of the parameters which are considered to assess the overall risk factor: risk impact, risk probability and risk discrimination. All of these factors are expressed by qualitative scales which are defined by trapezoidal fuzzy numbers to capture the vagueness in the linguistic variables. The most notable differences with other fuzzy risk assessment methods are the use of an algorithm to handle the inconsistencies in the fuzzy preference relation when pair-wise comparison judgements are necessary, and the use of trapezoidal fuzzy numbers until the defuzzification step. An illustrative example on risk assessment of a rehabilitation project of a building is used to demonstrate the proposed methodology

A fuzzy multi-criteria decision making model for construction contractor prequalification

Selecting an appropriate contractor is essential for the success of any construction project. Contractor prequalification procedure makes it possible to admit for tendering only competent contractor. Prequalification is a multi-criteria decision problem that is, in essence, largely dependent on the uncertainty and vagueness in the nature of construction projects and subjective judgement of the decision-maker. This paper presents a systematic prequalification procedure, based on Fuzzy Set Theory, whose main differences and advantages in comparison with other models are the use of an algorithm to handle the inconsistencies in the fuzzy preference relation when pair-wise comparison judgements are used and the use of linguistic assessment or exact assessment of performance of the contractors on qualitative or quantitative criterion, respectively. Finally, a case study for the rehabilitation project of a building at Technical University of Cartagena is presented to illustrate the use of the proposed model and to demonstrate its effectiveness

Last planner control system applied to a chemical plant construction

The main difference between the Last Planner production control system developed by Ballard and classical control systems is the way in which projects are controlled and planned. The Last Planner system focuses on controlling production units, workflows and the quality of the performed work. It also permits the identification of the causes for the non-completion of planned work and decision making in accordance with the project requirements so that actions are timely and productivity is increased. The objective of this paper is to present the results obtained from implementing the Last Planner system in the construction department of a chemical company. In this department, an information flow problem was detected among its members, in which supervisors lacked knowledge about the work to be performed until the project had been perfectly designed. This problem often led to meant long delays in the projects. The results from Last Planner system implementation show that identifying the constraints of the planned work leads to an improvement in the percentage and quality of completed activitie

Estudio de mercado de frutilla nativa (Fragaria chiloensis (L., Duch.)) en la Región Metropolitana

67 p.Este estudio de mercado forma parte de un proyecto financiado por la Fundación para la Innovación Agraria (FIA), el cual tiene por objetivo investigar la extensión de la época de cosecha y la presencia en el mercado nacional de la frutilla nativa chilena. El objetivo de este estudio fue analizar la disposición de restaurantes dirigidos al sector socioeconómico alto a incorporar en su carta la frutilla nativa. El estudio implementó una encuesta a restaurantes del sector Oriente de Santiago, específicamente en las comunas de Las Condes y Providencia, entre Diciembre de 2010 y Enero de 2011. Se aplicaron 34 encuestas con una degustación previa a administradores o chefs de restaurantes, 20 en la comuna de Providencia y 14 en la comuna de Las Condes. Los resultados demostraron que más de la mitad de los encuestados desconocía la frutilla nativa, pero una vez realizada la degustación e informados de las características organolépticas que posee, el 82% optó por utilizarla en diferentes preparaciones, principalmente en estado fresco para postres y jugos. Esto demuestra que existe interés en incluirla como producto gourmet, pero existe falta de conocimiento, por lo que es necesario implementar estrategias de marketing para hacerla conocida y llamar la atención de posibles clientes. De los encuestados dispuestos a incluir la frutilla en la carta de postres y jugos el 61% está dispuesto a pagar un sobreprecio comparado con el precio pagado por frutilla roja. El sobreprecio que están dispuestos a pagar está en un rango entre 17% a 400%, es decir desde $160 a los$3.200 adicionales al precio pagado por el kilo de frutilla roja./ABSTRACT: This market study is part of a project funded by the Foundation for Agricultural Innovation (FIA), which aims to research the extent of the harvest season and the presence in the domestic market for Chilean native strawberry. The objective of this study was to analyze the willingness to incorporate by restaurants oriented to high socioeconomic sector the native strawberry in their menu. The study implemented a survey to restaurants of the East sector of Santiago, specifically in the counties of Las Condes and Providencia, between December 2010 and January 2011. Thirty-four surveys were applied after a testing of the product to managers of chefs of the restaurant, 20 in Providencia and 14 in Las Condes. The results showed that more than half of respondents did not know the native strawberry, but once they tasted it and got information about the organoleptic characteristics a 82% were willing to use it in different preparations, mainly fresh in desserts and juices. This shows that there is interest in including it as a gourmet product, but there is lack of knowledge about it, which makes necessary to implement marketing strategies to make it known and attract the attention of potential customers. From the respondents that are willing to use de native strawberry in their menu of dessert and juices, 61% are willing to pay a premium compared to price paid for the red strawberry. The range of premium goes from 17% to 400% or in other words from $160 to$3.200 additional to the price of red strawberry

Evolución y tendencias en la industria fotovoltaica española

Durante la relativamente corta vida de las instalaciones fotovoltaicas en España con relación a otro tipo de energías, la regulación efectuada en los últimos años está jugando un papel fundamental en el desarrollo de esta industria. La energía solar fotovoltaica supone actualmente el 0,1% de la demanda en barras de central (muy lejano del 10% de la energía eólica, por ejemplo), eso sí, con un incremento de número de instalaciones que se dobla cada año, y con crecimientos anuales de energía vendida totalmente exponenciales, pero que está todavía muy lejos de suponer un coste excesivo al sistema (45 millones de euros en 2006 con respecto a los 1200 millones de euros vendidos a las distribuidoras, o los 3300 millones de euros de participación en el mercado, todos ellos dentro de las energías renovables)

Accessibility do not explain abundance of medium and large-sized mammals in Terra Do Meio, Altamira, Pará, Brazil

The aim of this study was to evaluate the effects of accessibility on hunting pressure by considering the mammal abundance and biomass of two protected areas belonging to different conservation categories -indigenous land and Ecological Station- in the Xingu River basin, eastern Amazon. For doing so, we used linear transection methods (total effort 240 km, in four tracks), camera traps (487 days) and complementary records. We also developed an accessibility coefficient based on the distance between navigable rivers and roads, and the center point of the sampled trails. We used the Simple linear regression test to analyze the effects of this accessibility on the biomass of the sighted species, gathering them in orders. We found 34 species belonging to seven families and six orders. We found no relation between mammal biomass and our accessibility index, which suggests that hunting pressure affects even the most distant studied areas.Nosso objetivo foi analisar os efeitos da acessibilidade sobre a pressão de caça refletida na abundância e biomassa de mamíferos em duas áreas protegidas de diferentes categorias de conservação. Terra indígena e Estação Ecológica, na bacia do rio Xingu, no leste da Amazônia. Para tal, usamos os métodos de transição linear (esforço de 240 km), armadilhas fotográficas (487 dias) e registros complementares. Adicionalmente, desenvolvemos um coeficiente de acessibilidade com base na distância dos rios e estradas navegáveis para o ponto central das trilhas percorridas. Utilizamos regressão linear simples para analisar os efeitos da acessibilidade sobre a biomassa das espécies avistadas (agrupadas em ordens). Encontramos 34 espécies pertencentes a 07 famílias. Não encontramos relação entre a biomassa de mamíferos e nosso índice de acessibilidade, sugerindo que a pressão de caça afeta a área estudada a uma maior distância