Composite pre-heating: Effects on marginal adaptation, degree of conversion and mechanical properties

Objectives. This study evaluated the effect of composite pre-polymerization temperature and energy density on the marginal adaptation (MA), degree of conversion (DC), flexural strength (FS), and polymer cross-linking (PCL) of a resin composite (Filtek Z350, 3M/ESPE). Methods. For MA, class V cavities (4mmx2mmx2mm) were prepared in 40 bovine incisors. The adhesive system Adper Single Bond 2 (3M/ESPE) was applied. Before being placed in the cavities, the resin composite was either kept at room-temperature (25 degrees C) or previously pre-heated to 68 degrees C in the Calset (TM) device (AdDent Inc., Danbury, CT, USA). The composite was then light polymerized for 20 or 40s at 600mW/cm(2) (12 or 24 J/cm(2), respectively). The percentage of gaps was analyzed by scanning electron microscopy, after sectioning the restorations and preparing epoxy resin replicas. DC (n = 3) was obtained by FT-Raman spectroscopy on irradiated and non-irradiated composite surfaces. FS (n = 10) was measured by the three-point-bending test. KHN (n = 6) was measured after 24h dry storage and again after immersion in 100% ethanol solution for 24 h, to calculate PCL density. Data were analyzed by appropriate statistical analyses. Results. The pre-heated composite showed better MA than the room-temperature groups. A higher number of gaps were observed in the room-temperature groups, irrespective of the energy density, mainly in the axial wall (p < 0.05). Composite pre-heating and energy density did not affect the DC, FS and PCL (p > 0.05). Significance. Pre-heating the composite prior to light polymerization similar in a clinical situation did not alter the mechanical properties and monomer conversion of the composite, but provided enhanced composite adaptation to cavity walls. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The marginal dentition of the Australian lungfish, Neoceratodus forsteri (Osteichthyes : Dipnoi)

The dentary, a component of the transient marginal dentition found in the mandible of juveniles of the living Australian lungfish Neoceratodus forsteri, is a tooth plate exactly comparable to the tooth plates with radiating ridges that make up the marginal dentitions of Devonian dipnoans like Andreyevichthys, Orlovichthys and Ichnomylax. In N. forsteri, the dentary consists of two ridges, set almost in line with each other, and growing by the addition of cusps, of increasing sizes, to the extremity of each ridge. It is therefore equivalent to two ridges of a more normal tooth plate with radiating ridges. Despite its appearance, as a long row of sharp cusps ankylosed to a slender bone, and its position, embedded in soft tissue above the anterolabial margin of Meckel's cartilage, it is a tooth plate and is not comparable to the marginal dentitions of other vertebrates. Structure and development of the transient marginal dentition of this lungfish is another indication that dipnoans may not be the sister group of tetrapods.

Deviance and marginal occupations: the case of taxi drivers

The taxi industry provides a strategic site to explore workplace deviance in low supervision, low status, occupational settings. Despite this theoretical opportunity and the objective importance of the taxi industry worldwide, very little is known about deviance among taxi drivers. Making use of interview data, this exploratory study maps out forms of workplace deviance and the explanations given for them by a sample of male taxi drivers. Major illegal activities reported included speeding, driving unsafe vehicles, taking drugs, and fraud. Theories pertaining to worker alienation, stress management, victim precipitation, and social control were relevant to the rationalizations some of the drivers provided to account for their illegal behaviors. We conclude that the occupational culture of taxi drivers and the structure of the taxi industry facilitate the forms of deviance reported here.

A mandibulectomia marginal no tratamento dos tumores de loja amigdalina e região retromolar

A ressecção do ramo ascendente da mandíbula ocasiona um déficit funcional e estético considerável. OBJETIVO: Comparar a mandibulectomia marginal e segmentar de tumores avançados de loja amigdalina e região retromolar sem envolvimento ósseo mandibular detectado no período pré-operatório, em relação à sobrevida e recidiva loco-regional. Forma de Estudo: Estudo de coorte contemporânea com corte transversal. MATERIAL E MÉTODO: Compararam-se 20 pacientes tratados com mandibulectomia marginal e 22 tratados com mandibulectomia segmentar de outubro de 1994 a dezembro de 2001 em serviço de referência em Cirurgia de Cabeça e Pescoço. RESULTADOS: Dos 20 pacientes tratados com mandibulectomia marginal, 35% morreram com doença, 15% por recidiva local, 15% por recidiva regional e 5% por recidiva loco-regional. Dos 22 pacientes tratados com mandibulectomia segmentar 45,4% morreram pela doença, sendo 31,8% por recidiva local e 13,6% por recidiva à distância. Na análise pelo método de Kaplan-Meier o grupo tratado com mandibulectomia marginal apresentou uma taxa de 55%, e o grupo tratado com ressecção segmentar 45% com p= 0,8329. CONCLUSÕES: A análise dos dois grupos evidenciou que a conservação do ramo ascendente da mandíbula, mesmo em lesões avançadas, sem envolvimento mandibular, não aumenta o índice de recidiva.

Macrófitas aquáticas de um lago marginal ao rio Embu-mirim, São Paulo, Brasil

Durante os anos de 1984/1985 obtiveram-se amostras sazonais para determinação de parâmetros físicos, químicos e biológicos de um lago marginal ao rio Embu-mirim, em Itapecerica da Serra, na bacia do reservatório de Guarapiranga (São Paulo, Brasil). Além de discutir os resultados obtidos quanto à flora de macrófitas aquáticas e suas relações com os outros parâmetros ambientais, são também analisados os efeitos da variação sazonal. As espécies encontradas estão presentes em diversos corpos d'água marginais, bem como ao longo do rio Embu-mirim, permitindo avaliar seu comportamento em corpos d'água semelhantes, da mesma bacia. A macrófita predominante foi Eichhornia crassipes (Mart.) Solms. Os resultados obtidos demostram a tendência de uma eutrofização acelerada e o risco de macrófitas potencialmente problemáticas, como E. crassipes e Salvinia auriculata, formarem camalotes de altas densidades, que podem chegar ao reservatório de Guarapiranga, através do rio Embu-mirim, causando problemas aos diversos usos da água.

Virtual power players demand response programs management based on locational marginal prices

Power systems have been suffering huge changes mainly due to the substantial increase of distributed generation and to the operation in competitive environments. Virtual power players can aggregate a diversity of players, namely generators and consumers, and a diversity of energy resources, including electricity generation based on several technologies, storage and demand response. Resource management gains an increasing relevance in this competitive context, while demand side active role provides managers with increased demand elasticity. This makes demand response use more interesting and flexible, giving rise to a wide range of new opportunities.This paper proposes a methodology for managing demand response programs in the scope of virtual power players. The proposed method is based on the calculation of locational marginal prices (LMP). The evaluation of the impact of using demand response specific programs on the LMP value supports the manager decision concerning demand response use. The proposed method has been computationally implemented and its application is illustrated in this paper using a 32 bus network with intensive use of distributed generation.

Demand Response Design and Use Based on Network Locational Marginal Prices

Power systems have been experiencing huge changes mainly due to the substantial increase of distributed generation (DG) and the operation in competitive environments. Virtual Power Players (VPP) can aggregate several players, namely a diversity of energy resources, including distributed generation (DG) based on several technologies, electric storage systems (ESS) and demand response (DR). Energy resources management gains an increasing relevance in this competitive context. This makes the DR use more interesting and flexible, giving place to a wide range of new opportunities. This paper proposes a methodology to support VPPs in the DR programs’ management, considering all the existing energy resources (generation and storage units) and the distribution network. The proposed method is based on locational marginal prices (LMP) values. The evaluation of the impact of using DR specific programs in the LMP values supports the manager decision concerning the DR use. The proposed method has been computationally implemented and its application is illustrated in this paper using a 33-bus network with intensive use of DG.

Seroepidemiology of toxoplasmosis in women of childbearing age from a marginal community of Maracaibo, Venezuela

The aim of this study was to determine the prevalence of anti-T. gondii total and IgM antibodies in women of childbearing age. One hundred serum samples of women were studied with age range from 11 to 45 years old. Samples were chosen by random. The determination of total antibodies was carried out through the indirect hemagglutination technique and IgM antibodies by ELISA's technique. The statistical analysis was carried out through the Chi square and the Spearman correlation tests. The theoretical estimated incidence of congenital toxoplasmosis was calculated, according to the annual increment of antibody prevalence among the age groups. The overall prevalence of toxoplasmosis was 33%, while only six individuals (18.2%) were positive to IgM. The highest prevalence was observed in the 11-35 year-old age group. The theoretical estimated incidence was 1.5 for 100 pregnancies in women of 21-25 year-old group; it decreased until 0.1% in the 41-45 year-old age group. The findings show a high prevalence of toxoplasmosis in this community with a high infection risk in women of the studied age group and the high cat population observed, suggesting that the transmission way by contaminated soils may play a main role in the spreading of toxoplasmosis in this community.

Seroprevalence and sociocultural conditionants of Chagas disease in school aged children of marginal zones of Asunción

Chagas disease is becoming a public health problem in Latin America due to the wide distribution, the high prevalence, the magnitude of the damage caused and the difficulties to control it. In Paraguay, the disease is mainly distributed in the departments of Paraguari, Cordillera and Central. Prevalence in marginal zones, where migrations from rural populations and endemic areas make possible the urbanization of the disease, has no been studied yet. This is a descriptive study with a cross-sectional sampling and a probabilistic system recruitment carried out in school aged children from marginal zones of Asuncion to determine the prevalence of Chagas' disease. Serological methods, parasite isolation and questionnaires were used to achieve the goals. Nine hundred and fifty three children were studied to determine the prevalence of Chagas' disease in marginal zones which was 1.4%.

O provérbio: um género marginal(izado)?!

Enquanto o provérbio, numa cultura de tradição oral, representa tipicamente o tesouro do conhecimento e a colecção das regras sociais ou jurídicas, na transição para a cultura escrita e na formulação científica dos saberes, esse género da Literatura Tradicional perde a sua autoridade nos círculos dominantes da sociedade. Ressalve-se, porém, o facto de, ao longo desse processo, haver ciclos.

Managing marginal capital requirements in solvency II: Analysis of a real insurance portfolio

This thesis provides a complete analysis of the Standard Capital Requirements given by Solvency II for a real insurance portfolio. We analyze the investment portfolio of BPI Vida e Pensões, an insurance company affiliated with a Portuguese bank BPI, both at security, sub-portfolio and asset class levels. By using the Standard Formula from EIOPA, Total SCR amounts to 239M€. This value is mostly explained by Market and Default Risk whereas the former is driven by Spread and Concentration Risks. Following the methodology of Leblanc (2011), we examine the Marginal Contribution of an asset to the SCR which allows for the evaluation of the risks of each security given its characteristics and interactions in the portfolio. The top contributors to the SCR are Corporate Bonds and Term Deposits. By exploring further the composition of the portfolio, our results show that slight changes in allocation of Term and Cash Deposits have severe impacts on the total Concentration and Default Risks, respectively. Also, diversification effects are very relevant by representing savings of 122M€. Finally, Solvency II represents an opportunity for the portfolio optimization. By constructing efficient frontiers, we find that as the target expected return increases, a shift from Term Deposits/ Commercial Papers to Eurozone/Peripheral and finally Equities occurs.

Persistence of the embryonic lateral marginal vein: report of two cases

PURPOSE: Congenital venous malformations of the lower limbs represent a particular challenge for the vascular surgeon. Persistence of fetal veins is a rare malformation, and the most common is the persistence of the lateral marginal vein usually observed in patients with Klippel-Trenaunnay Syndrome. The persistence of this embryonic vein as an isolated venous malformation without the other characteristics of the Klippel-Trenaunnay Syndrome has not yet been reported. This paper describes two cases. METHODS: Two patients, a 17-year-old male patient and a 16-year-old female, have had since their birth a large venous trunk in the lateral aspect of the right leg and thigh. The limbs underwent duplex scanning and phlebography. The surgical removal of the lateral marginal vein was performed. RESULTS: Surgical treatment resulted in very good functional and aesthetic results. Follow-up at 26 months showed no evidence of varicose vein recurrence. CONCLUSIONS: To achieve good results, surgical intervention may be indicated in cases of orthopedic deformity, hemorrhage, symptomatic, and unaesthetic lesions.

Creaciones fitogenéticas en Maíz con respuesta adaptativa a la zona marginal

La creación de una población mejorada de maíz, requiere al menos tres etapas: a) La conformación de una "población original" con variabilidad genética, b) La selección preliminar de plantas y/o progenies, y c) La "evaluación" en condiciones de campo de las mejores descendencias integradas en poblaciones experimentales. Precisamente, este proyecto está dirigido a la creación de variedades con estabilidad de rendimientos en las condiciones ambientales de la zona centro-norte de la Provincia de Córdoba, en donde el maíz es el único cereal que se cosecha y una de las mejores posibilidades como forrajera estival. Se ha inscripto el cv. "MPB-FCA 856", un maíz colorado duro creado para la producción de granos, que en marcado déficit hídrico produce rendimientos superiores a otros cultivares. Actualmente se dispone de una variedad sintética, próxima a ser inscripta como una nueva creación. Con orientación al desarrollo de otros cultivares, se plantean las líneas de trabajo que se enumeran seguidamente: Tema 1. Maíz Colorado Duro: Obtención de una variedad sintética. Se iniciará la caracterización varietal a fin de inscribir en el Instituto Nacional de Semillas el nuevo cv. sintético formado por 10 líneas S1, que presenta altos rendimientos de granos. Tema 2. Maíz Forrajero: Desarrollo de un cultivar con aptitud para ser utilizado como forraje en planta. En la zona marginal el pastoreo de lotes de maíz es común tanto en años con pocas precipitaciones pluviales como en ciclos favorables, por cuanto es una muy buena alternativa de forraje estival tanto en verdeo, silo o diferido. Se dispone de líneas propias con características de alto macollamiento y capacidad de rebrote; se plantea su mejoramiento por caracteres que hacen a la calidad forrajera, tales como porcentaje de materia seca, palatabilidad, fibra bruta, etc. Tema 3. Mejora en la eficiencia de selección para tolerancia a estrés hídrico en maíz ( Zea mays L.). Aportar evidencia experimental que mejore la eficiencia de la selección, cuando los genotipos se dispersarán en una gama de ambientes contrastantes por su disponibilidad hídrica. Se comenzará un esquema de selección recurrente en ambientes con diferente disponibilidad hídrica, empleando características que permitan identificar genotipos tolerantes. Paralelamente se implementarán metodologías de evaluación del germoplasma disponible mediante pruebas de laboratorio y campo, a fin de detectar fuentes de genes para tolerancia al estrés hídrico.

Propuesta de servicios de asesoramiento para el mantenimiento de la vivienda y el barrio en sectores de recursos insuficientes

La vivienda es un bien duradero y por ello debe cumplir una vida útil que está condicionada por los pasos anteriores a su construcción, por la construcción misma y por su uso posterior. En este proceso económico-técnico la vivienda constituye el capital y sus habitantes son los consumidores. Un 60% de la población, incluidos los sectores de bajos recursos, prioritariamente realizan sus viviendas, mejoras, ampliaciones y modificaciones sin ningún tipo de asesoramiento técnico-profesional. Esto produce obra clandestina con numerosas irregularidades al no respetar normas, ordenanzas, reglamentaciones y condiciones mínimas de habitabilidad. Debe haber mayor información, darse difusión a todas las ordenanzas, dar a conocer y agilizar tramitaciones. (...) Objetivos generales *Producir nuevos servicios a la comunidad; el resultado a largo alcance es el de crear un sistema de información y asesoramiento que contribuya a mejorar la calidad de vida de los sectores de menores recursos mediante el correcto uso y mantenimiento de la vivienda y el barrio. * Generar un proceso de Investigación Acción entendida como prestación de Servicios de Asesoramiento e información utilizando los medios de comunicación, los recursos humanos y comunitarios brindados por las instituciones públicas y privadas que contribuyan al desarrollo barrial. (...) Objetivos específicos * Proveer información que oriente y facilite el mantenimiento de los sectores sociales en la vivienda de bajos recursos. * Crear condiciones técnicas y de diseño para que la inversión económica del esfuerzo familiar sea redituable a largo plazo, mediante la programación de la vida útil de la vivienda. * Lograr operatorias de autoconstrucción para realizar trabajos de completamiento, modificaciones, ampliaciones, refacciones, etc. a nivel barrial. * Colaborar mediante la utilización de criterios de diseño diversos a la adaptación a nuevos usos o necesidades de los usuarios a través del tiempo. Adecuación a las distintas etapas de la vida familiar. * Transferir los resultados de la investigación y experiencias realizadas al sector productivo para su desarrollo y adecuación a las necesidades de los usuarios. * Generar estudios sobre la calidad residencial, cambios y transformaciones en la vivienda social. * Lograr la transferencia de conocimientos de la Facultad hacia el medio y la retroalimentación hacia el proceso de enseñanza-aprendizaje.