O objetivo deste estudo foi avaliar a resistência de união à dentina da obturação de canais radiculares com cimentos à base de resina epóxica e de metacrilato, por meio do dispositivo material testing stage (MTS) acoplado ao microtomógrafo (&mu;CT), bem como avaliar qualitativamente a ruptura da massa obturadora por meio de imagens de &mu;CT. Além disso, foram utilizados o método de elementos finitos 3D e microscopia confocal de varredura a laser (MCVL) para verificar, respectivamente, a distribuição de tensões e presença de gaps na interface de união. Raízes de caninos superiores com 17 mm de comprimento foram submetidas ao preparo biomecânico com instrumentos rotatórios de níquel titânio, sob irrigação constante com NaOCl 1% e irrigação final com EDTA 17%. Os canais foram obturados pela técnica da condensação lateral com cones de guta percha e os cimentos: AH Plus, Epiphany SE ou RealSeal XT. As raízes foram armazenadas (100% de umidade, 37°C) por três vezes o tempo de endurecimento do cimento utilizado. Após este período, as raízes foram seccionadas para obtenção de dois slices (2 mm) de cada terço radicular. Um slices de cada terço foi submetido ao teste de push-out através de dispositivo mecânico MTS acoplado ao &mu;CT SkyScan 1174 (50kV, 80mA). Após o escaneamento inicial do slices, com resolução isotrópica de 13 &mu;m, filtro de 0.5 mm de Al e 360º de rotação, o teste mecânico foi iniciado até que ocorresse o deslocamento do material. Novo escaneamento foi realizado com os mesmos parâmetros iniciais, que determinou regiões de ruptura da massa obturadora em secções axiais. Os tipos de falhas foram avaliados por MCVL e classificadas em: adesivas, coesivas e mistas. Modelos 3D de elementos finitos foram gerados para os terços cervical, médio e apical, a partir de imagens de &mu;CT. No segundo slices de cada terço radicular, foi aferido o percentual de gaps do material obturador às paredes do canal radicular, por meio de MCVL e do programa OLS 4000. Os dados foram analisados por testes estatísticos paramétricos e não paramétricos (p<0,05). O cimento AH Plus [1,89 (1,01/2,39) MPa] apresentou maior resistência de união à dentina (p<0,001) quando comparado aos cimentos Epiphany SE [0,36 (0,29/0,44) MPa] e RealSeal XT [0,43 (0,32/0,54) MPa]. Para os cimentos AH Plus e RealSeal XT, os terços cervical e médio apresentaram maior resistência de união à dentina que o terço apical (p<0,001). As rupturas ocorreram nas margens da massa obturadora para o cimento AH Plus, enquanto os cimentos Epiphany SE e RealSeal XT tiveram este tipo de ruptura, bem como na própria massa obturadora. No cimento AH Plus, a interface de união mostrou maior concentração de tensões, que foram distribuídas principalmente na massa obturadora para os cimentos Epiphany SE e RealSeal XT. Houve predominância de falhas adesivas e mistas em todos os cimentos. Em relação ao percentual de gaps, o cimento AH Plus apresentou as menores médias (11,14% ± 4,03), com diferença estatisticamente significante (p<0,05) dos cimentos Epiphany SE (55,39% ± 13,46) e RealSeal XT (62,50% ± 6,72). O cimento à base de resina epóxica (AH Plus) apresentou a maior resistência de união à dentina e teve comportamento diferente em relação aos outros cimentos, quanto à ruptura da massa obturadora e distribuição de tensão interfacial. Além disso, o cimento AH Plus apresentou o menor percentual de gaps entre o material obturador e as paredes do canal radicular / The aim of this study was to evaluate the bond strength of epoxy resin- and methacrylate-based sealers to root dentin, using the material testing stage (MTS) coupled to a micro-computed tomography (&mu;CT) device and to qualitatively assess the root-filling mass rupture by &mu;CT images. Additional analyses were conducted using the 3D element finite method and confocal laser scanning microscopy (CLSM) to verify, respectively, the stress distribution and percentage of gaps on dentin filling material interfaces. Maxillary canine roots measuring 17 mm were subjected to biomechanical preparation with nickel-titanium rotary instruments under constant irrigation with 1% NaOCl and final irrigation with 17% EDTA. Canals were filled by the lateral condensation technique with gutta-percha cones and the following sealers: AH Plus, Epiphany SE or RealSeal XT. The roots were stored (100% humidity, 37 °C) for a period three times longer than the setting time required for each sealer and then sectioned transversally to obtain two 2-mm-thick slices from each root third. One slice of each third was subjected to the push-out test using the MTS coupled to the SkyScan 1174 &mu;CT (50 kV, 80 mA) with 13 &mu;m isotropic resolution, 0.5 mm Al filter and 360° rotation. After the initial scanning of the slice, the mechanical test was performed until material dislodgement occurred. A new scanning was performed using the same initial parameters. The axial sections obtained were used for qualitative evaluation of the root-filling mass rupture. Failure modes were assessed by CLSM and classified as adhesive, cohesive or mixed. 3D &mu;CT based finite element models were generated from cervical, middle and apical root thirds to simulate the push-out test. The second slice of each root third was used to assess the percentage of gaps between the filling material and the root canal walls, using CLSM with the aid of the OLS 4000 software. The data were analyzed by parametric and non-parametric tests (p<0.05). AH Plus presented higher bond strength [1.89 (1.01/2.39) MPa] to dentin (p<0.001) than Epiphany SE [0.36 (0.29/0.44) MPa] and RealSeal XT [0.43 (0.32/0.54) MPa]. For AH Plus and RealSeal XT sealers, the cervical and middle thirds showed higher bond strength to dentin than the apical third (p <0.001). The ruptures occurred in the margins of the root filling mass for AH Plus, while Epiphany SE and RealSeal XT had this type of rupture as well as in the root filling mass itself. AH Plus showed stress concentration on bond interface, while in Epiphany SE and RealSeal XT the stress was mainly distributed on the root-filling mass. Adhesive and mixed failures were the predominant fracture modes in all sealers. Regarding the percentage of gaps between the filling material and the root canal walls, AH Plus presented the lowest means (11.14%±4.03), differing significantly (p<0.05) from Epiphany SE (55.39%±13.46) and RealSeal XT (62.50%±6.72) sealers. The epoxy resin-based sealer (AH Plus) presented the highest bond strength to dentin, which had different behavior from other sealers regarding root-filling mass rupture and interfacial stress distribution. Moreover, AH Plus resulted in the lowest percentage of gaps between the material and the root canal walls

Introdução: A gastrostomia percutânea endoscópica (PEG) é utilizada como via de nutrição para pacientes sem capacidade de utilizar a via oral para manter ingestão suficiente. A disfagiaé uma das principais razões para a indicação da PEG, sendo geralmente atribuída a processos neurodegenerativos. Diferentes técnicas e tipos de sonda são utilizadas para confecção da PEG. A técnica de Tração é o método original, na qual a sonda é tracionada a partir de uma pequena incisão na parede abdominal, através a boca e do esôfago até estar posicionada junto da parede gástrica. A técnica de punção com gastropexia é uma variante da técnica de punção original, na qual a sonda não passa pela cavidade oral. Nesta técnica, após fixação do estômago na parede abdominal com uso de pontos, a sonda é introduzida diretamente através da parede abdominal sob visão endoscópica. De acordo com a técnica, diferentes modelos de sondas podem ser utilizadas, cada uma com diferentes tipos de retentores internos. Os retentores internos maiscomuns são: em forma de diamante, em forma de cogumelo, disco rígido e balão. Possivelmente, tanto a técnica de inserção como os modelos de sondas e retentores utilizados podem estar associados a diferentes desfechos. O objetivo deste estudo foi avaliar a incidência podem estar associados a diferentes desfechos. O objetivo deste estudo foi avaliar a incidência. Métodos: Foi realizada uma coorte histórica na qual foram incluídos todos os pacientes maiores de 18 anos submetidos à colocação de uma primeira PEG entre janeiro de 2010 e dezembro de 2015 no Hospital Moinhos de Vento, um hospital privado em Porto Alegre, sul do Brasil. Os dados foram coletados em formulário padronizado através de uma busca no sistema informatizado da Instituição. Para complementação dos dados foi realizada uma busca nos prontuários digitalizados, e em algumas situações realizado contato telefônico. Resultados: Foram identificados 245 pacientes, sendo 200 submetidos a técnica de tração (Pull) e 45 à técnica de punção com gastropexia (Push com gastropexia). A média da idade foi 80,3±13,3 anos. Cento e trinta e quatro (54,7%) pacientes eram do sexo feminino. O período médio de seguimento foi de 17,2±14,6 meses. A indicação mais comum foi doença neurodegenerativa (62,4%), seguido por acidente vascular cerebral (AVC) (16,3%). Todos os pacientes realizaram profilaxia com antibiótico no dia do procedimento. A mediana de dias de internação pós PEG foi de 8 dias. O modelo de sonda mais utilizado foi o retentor em forma de diamante (51,8/%). A colocação da PEG foi bem-sucedida em 99,6% dos casos. A mortalidade geral foi de 42,4% (104/245) durante o período de seguimento. Nenhum óbito foi atribuído diretamente a complicações relacionadas ao procedimento. Entretanto, três pacientes faleceram dentro de 48 horas após o procedimento: um por sepse respiratória, outro por parada cardiorrespiratória e o terceiro que realizou a PEG ambulatorial teve morte súbita no domicílio. A taxa de complicações (maiores ou menores) foi de 23,6%, sendo a mais frequente, a retirada acidental da sonda, que ocorreu em 17,1% dos pacientes em algum momento do seu seguimento. Não foi observada diferença entre as técnicas de realização da PEG gastrostomia com a incidência desta complicação. O tempo até a retirada acidental da sonda foi menor entre os pacientes cujas sondas tinham o retentor interno em forma de diamante em relação aos demais retentores (p = 0,02). Sepultamento do retentor interno (Buried Bumper Syndrome) ocorreu em 5,4% dos casos, todos submetidos a técnica de tração (p = 0,08). Pacientes portadores de sonda com retentor em forma de diamante apresentaram maior incidência de complicações gerais (p = 0,02) e de retirada acidental (p = 0,01), comparativamente aos pacientes portadores de sondas com outros tipos de retentor. Conclusões: A PEG é uma técnica segura, com baixa taxa de mortalidade diretamente associada ao procedimento. Entretanto, devido a população na qual o procedimento é realizado, a mortalidade geral é elevada. Complicações menores são frequentes, independentemente da técnica ou tipo de sonda utilizada, porém a técnica e o tipo de sonda parecem associadas a um perfil diferente de complicações. Perspectivas: O desenvolvimento da técnica, o desenvolvimento de materiais com melhor perfil de segurança e, especialmente, o aprimoramento das orientações e cuidados pós-gastrostomia são necessários para reduzir a incidência de complicações em pacientes submetidos a esse tipo de procedimento. Novos estudos comparando de maneira prospectiva e randomizada diferentes técnicas e modelos de sonda são necessários para determinar se há uma técnica ou modelo a ser utilizado como primeira escolha.

The Service Worker is a programmable proxy that allows the clients to keep offline parts of websites or even the whole domains, receive push notifications, have back-ground synchronization and other features. All of these features are available to the user without having to install an application - the user only visits a website. The service worker has gained popularity due to being a key component in the Progressive Web Applications (PWAs). PWAs have already proven to drastically increase the number of visits and the duration of browsing for websites such as Forbes [1], Twitter [2], and many others. The Service Worker is a powerful tool, yet it is hard for clients to understand the security implications of it. Therefore, all modern browser install the service workers without asking the client. While this offers many conveniences to the user, this powerful technology introduces new security risks. This thesis takes a closer look at the structure of the service worker and focuses on the vulnerabilities of its components. After the literature analysis and some testing using the demonstrator developed during this project, the vulnerabilities of the service worker components are classified and presented in the form of the vulnerability matrix; the mitigations to the vulnerabilities are then outlined, and the two are summarized in the form of security guidelines.

Functional heterojunctions in organic electronic devices are interfaces formed either between a conducting electrode and an organic semiconductor or between two different organic semiconductors in blended and multilayered structures. This thesis is primarily concerned with the energy level alignment and the interfacial electronic structures at functional heterojunctions encountered in electronic devices made with solution-processable semiconducting polymers. Investigations on the electronic structures across these heterointerfaces are performed with the combined use of electromodulation and photoemission spectroscopic techniques. Electromodulation and ultraviolet photoemission spectroscopic techniques enable direct determination of the surface work functions of electrodes at the electrode/semiconducting polymer interfaces. We overcame the inherent problems faced by electromodulation spectroscopy, which undermine accurate determination of interfacial electronic structures, by performing electroabsorption (EA) measurements at reduced temperatures. We showed in this thesis that low-temperature EA spectroscopy is a surface sensitive technique that can determine the interface electronic structures in electrode/polymer semiconductor/electrode diodes. Using this technique, we demonstrated that the energy level alignments in these solution-processed organic electronic devices are determined by the surface work functions of passivated metals rather than by those of clean metals encountered in ultrahigh vacuum. This thesis also discloses our studies on the electronic structures in polymeric diodes with type II donor-acceptor heterojunctions using the EA spectroscopy. We showed that minimising meausurement temperature and attenuating EA illumination intensity enable accurate determinations of the electronic structures in these devices. We demonstrated that the electronic structures and the performance characteristics of multilayered polymer light-emitting diodes are also determined by the surface work functions of passivated metals. Our investigations confirm that electronic doping of the organic active layers, rather than minimisation of the Schottky barriers at electrode/polymer contacts, holds the key in realising high-performance organic light-emitting devices.

No description available.

The news landscape has changed during recent years because of the digitization. News can nowadays be found in both newspapers and on different sites online. The availability of the digital newspapers leads to competition among the news companies. To make the users stay on one specific platform for news, relevance is required in the content and oneway of creating relevance is through personalization, to tailor the content to each user. The focus of this thesis is therefore personalizing newspush notifications for a digital  newspaper and making them more relevant for users. The project was made in cooperation with VK Media, and their digital newspaper. The task in this thesis is to implement personalization of push notifications by building a recommendation system and to test the implemented system with data from VK. In order to perform the task, a dataset representing reading habits of VK’s users was extracted from their data warehouse. Then a user-based and content-based recommendation system was implemented in Python.The idea with the system is to recommend new articles that are sufficiently similar to one or more of the already read articles. Articles that may be liked by one of the most similar users should also be recommended. Finally, the system’s performance was evaluated with the data representing reading habits for VK’s users. The results show that the implemented system has better performance than the current solution without any personalization, when recommending a few articles to each user. The results from the evaluation also show that the more articles the users have read, the better predictions are possible to make. Thus, this thesis offers a first step towards meeting the expectations of more relevant content among VK’s users.

After the second world war it became common for individuals in economically unstable countries to work migrate towards countries with better work opportunities. Common for this type of migration is that the individual only works for a few years before re-emigrating to their home country. In the town of Olofström in southern Sweden of the migrant workers an overwhelming majority instead chose to permanently settle. By examining the worker migration during the 60- and 70s in Olofström through archive studies and interviews with the individuals involved in the worker migration, this study aims to examine the push-pull-factors that were the basis for the individual's decision to permanently settle instead of re-emigrate. The study shows that it was partially a “lucky” coincidence that the surroundings of Olofström was very similar to the migrant workers home areas, but also that the municipality in Olofström was willing to spend enormous resources to develop their school system for the migrant workers' children played a big role. A well-built school system that gave the Finnish children an opportunity to receive a good education in both the foreign language and their mother tongue proved to be a bigger pull-factor than social acceptance was a push-factor.

The purpose of this thesis is to analyze the various reasons that have contributed to the decisionof international students not to return to their home countries after completing their studies, with a focus on students from Rwanda, Nigeria, and Cameroon. The study will include information about student’s home countries to provide a greater understanding of where they come from and how this has contributed to the decisions they have made. The push and pull factor theory will help to understand the different reasons why people choose to immigrate instead of staying in their home countries and what becomes a pull factor in the whole process. To gain even more insight into the students' choice not to return home, semistructured interviews with the 10 individuals will become important. By interviewing the 10 individuals from Rwanda, Nigeria, and Cameroon, one could tell that the countries have had amajor impact on the students' choice not to return home. Results showed that many chose not to return home because of the political instability that council in their home countries, some also felt living a life where they did not have to worry about tomorrow was an important factor in not going back home. The conclusion drawn was that countries were losing talented people because of their inability to put the needs of their citizens first.

A significant progress in the evolution of the computer systems and their interconnection over the past 70 years has allowed replacing the frequently used centralized architectures with the highly distributed ones, formed by independent entities fulfilling specific functionalities as one user-intransparent unit. This has resulted in an intense scientic interest in distributed algorithms and their frequent implementation into real systems. Especially, distributed algorithms for multi-sensor data fusion, ensuring an enhanced QoS of executed applications, find a wide usage. This doctoral thesis addresses an optimization and an analysis of the distributed systems, namely the distributed consensus-based algorithms for an aggregate function estimation (primarily, my attention is focused on a mean estimation). The first section is concerned with a theoretical background of the distributed systems, their evolution, their architectures, and a comparison with the centralized systems (i.e. their advantages/disadvantages). The second chapter deals with multi-sensor data fusion, its application, the classification of the distributed estimation techniques, their mathematical modeling, and frequently quoted algorithms for distributed averaging (e.g. protocol Push-Sum, Metropolis-Hastings weights, Best Constant weights etc.). The practical part is focused on mechanisms for an optimization of the distributed systems, the proposal of novel algorithms and complements for the distributed systems, their analysis, and comparative studies in terms of such as the convergence rate, the estimation precision, the robustness, the applicability to real systems etc.

Sveriges storstäder och många kommuner i större regioner tampas alltmer med bostadsbrist, där platsen inte räcker till för invånarna. På Sveriges landsbygder är problemet tvärtom, på platsen finns inte en fördelaktig befolkningsmängd. I Filipstads kommun är avfolkningen ett stort problem, inte minst när den unga befolkningen väljer att flytta, vilket leder till en hög medelålder och en minskad arbetskraft som bidrar med låga skatteintäkter. Att många unga väljer att flytta från landsbygden är ingen hemlighet, men i denna uppsats är syftet att förstå varför unga personer faktiskt väljer att bo kvar på landsbygden, med fokus på Filipstads kommun. Uppsatsens syfte är att förstå varför unga i Filipstads kommun väljer att gå mot den rådande urbaniseringsnormen som finns och faktiskt bo kvar på landsbygden. Utifrån detta är även syftet att studera om det finns skillnader i inställningen bland unga kvinnor och män. För att uppfylla syftet har elever på Spångbergsgymnasiet i Filipstads kommun tagits till hjälp genom en webbaserad enkät, för att få inblick i deras inställning till sin hemkommun. För att få förståelse för hur kommunen arbetar strategiskt i att bibehålla den unga befolkningen, har intervjuer utförts med tjänstepersoner på Filipstads kommun. I arbetet har tidigare forskning och teorier använts såsom push- and pullteorin, migration i förhållande till genus samt nyckelbegreppet plats som även inkluderat aspekter av platsbundenhet och bruksanda. Detta har gett oss stor förståelse till varför situationen ser ut som den gör i denna kommun. Resultatet visade att inställningen mellan unga kvinnor och män skiljer sig åt, då det framförallt är kvinnor som har en negativ inställning till Filipstads kommun. Den största skillnaden fanns dock inte mellan könen, utan mellan högskoleförberedande- och yrkesprogram. Detta då det främst var elever inom yrkesprogram som uttryckte en vilja av att bo kvar inom kommunen. Orsakerna till varför dessa unga människor i gymnasieålder vill bo kvar, grundade sig i en typ av platsbundenhet till familj och vänner samt även hopp och löfte om framtida arbete. Tjänstepersonerna på kommunen redogjorde i sin tur att kommunen inte har en övergripande strategi eller ett arbete för att bibehålla den unga befolkningen. Det är istället upp till varje förvaltning att göra det de kan i sitt arbete. Fokus inom Filipstads kommun ligger istället i att vara attraktiva för barnfamiljer, med hopp om att de utflyttande ska återvända när det är dags att bilda familj.