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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Cytologic studies of the fallopian tube in patients undergoing salpingo-oophorectomy

Chen, Hao, Klein, Robert, Arnold, Stacy, Chambers, Setsuko, Zheng, Wenxin 01 October 2016 (has links)
Background: Mounting evidence suggests the fallopian tube as the origin for ovarian high grade serous carcinoma (HGSC). We attempted to identify the tubal cytological features that allow us to distinguish malignant from benign conditions. Methods: Tubal specimens (n = 56) were collected from patients who underwent bilateral salpingo-oophorectomy (BSO) due to various clinical indications. A standard procedure to collect fallopian tube brushings from freshly received surgical specimens was developed. Cytological diagnoses were classified into three categories: benign, atypical, and suspicious for malignancy/malignant. Cytological variables of individual cells and epithelia were subjected to statistical analysis. The fallopian tube histology was used as diagnostic reference for confirmation of cytology diagnosis. Results: Among the 56 fallopian tube specimens, 2 (3.7 %) showed inadequate cellularity preventing further evaluation, 11 (20.4 %) were diagnosed as malignant or suspicious of malignancy, 7 were atypical, and 36 were benign. The presence of three dimensional clusters (p < 0.0001, Fisher's Exact Test), or prominent nucleoli (p = 0.0252, Fisher Exact test) was highly correlated with the diagnosis of malignancy. The suspicious malignant/malignant cytological diagnosis was also highly correlated with presence of HGSC with or without serous tubal intraepithelial carcinoma (STIC). Conclusions: Tubal cytology may be useful for ovarian cancer screening and early detection.
22

Analyse dynamique de la biodégradation du bois et des composites à base de bois et fibres végétales

Surini, Thibaud 05 October 2009 (has links)
La biodégradation du bois est étudiée pour comprendre et quantifier l’endommagement mécanique résultant. Il apparaît que le bois, et notamment le pin maritime, est sensible à une attaque fongique, faisant baisser sa résistance (en compression ou en fissuration) avant même la constatation d’une perte de masse. Cette observation oblige à développer des outils de détection précoce, comme la relaxométrie RMN, pour détecter l’apparition d’un pathogène sur des structures bois de plus en plus encouragées. Par ailleurs, l’emploi de composites à base de bois s’avère justifié pour rendre durable le matériau, et présente un avantage écologique, grâce au recyclage des éléments comme le plastique. Cet argument « vert » est d’une importance grandissante et requiert le développement de nouveaux procédés de préservation du bois. Ainsi, cette thèse étudie aussi le comportement à plus ou moins long terme des bois imprégnés d’anhydrides et d’huile d’origine végétale, ou encore du bois traité thermiquement. Des domaines autres que la mécanique sont abordés, afin d’expliquer l’ensemble des phénomènes intervenant durant une dégradation et comprendre les axes d’amélioration dans cette discipline « vivante ». / Wood biodegradation is studied in order to understand and quantify the mechanical damage. Wood, and especially maritime pine, is sensitive to a fungal attack that causes a decrease of its strength (compression or fracture resistance), before a weight loss occurs. This requires developing or ameliorating the tools of early detection, such as NMR relaxometry, in order to detect the appearance of a pathogen in wooden structures that are more and more appreciated. Besides, wooden composites are a good alternative to make the material more durable, and are ecologically interesting, as they permit to recycle some element, like plastics. This “green” effect is of main importance, which implies a development of new ways in wood preservation. This thesis, led in a short as well as in a long term scale, also studies the behaviour of wood, impregnated with anhydrides or oils from a vegetal origin, or even heat-treated wood. Not only mechanics is described, so that many phenomena are explained and perspectives are clarified.
23

Development of a novel virtual environment for assessing cognitive function : design, development and evaluation of a novel virtual environment to investigate cognitive function and discriminate between mild cognitive impairment and healthy elderly

Shamsuddin, Syadiah Nor Wan January 2012 (has links)
Alzheimer's disease (AD) is neurodegenerative disorder that causes memory loss and cognitive dysfunction. It affects one in five people over the age of 80 and is distressing for both sufferers and their families. A transitional stage between normal ageing and dementia including AD is termed a mild cognitive impairment (MCI). Recent studies have shown that people with MCI may convert to AD over time although not all MCI cases progress to AD. Much research is now focussing on early detection of AD and diagnosing an MCI that will progress to AD to allow prompt treatment and disease management before the neurons degenerate to a stage beyond repair. Hence, the ability to obtain a method of identifying MCI is of great importance. Virtual reality plays an important role in healthcare and offers opportunities for detection of MCI. There are various studies that have focused on detection of early AD using virtual environments, although results remain limited. One significant drawback of these studies has been their limited capacity to incorporate levels of difficulty to challenge users' capability. Furthermore, at best, these studies have only been able to discriminate between early AD and healthy elderly with about 80% of overall accuracy. As a result, a novel virtual simulation called Virtual Reality for Early Detection of Alzheimer's Disease (VREAD) was developed. VREAD is a quick, easy and friendly tool that aims to investigate cognitive functioning in a group of healthy elderly participants and those with MCI. It focuses on the task of following a route, since Topographical Disorientation (TD) is common in AD. An investigation was set up with two cohorts: non-elderly and elderly participants. The findings with regard to the non-elderly are important as they represent a first step towards implementation with elderly people. The results with elderly participants indicate that this simulation based assessment could provide a method for the detection of MCI since significant correlations between the virtual simulation and existing neuropsychological tests were found. In addition, the results proved that VREAD is comparable with well-known neuropsychological tests, such as Cambridge Neuropsychological Automated Test Battery, Paired Associate Learning (CANTAB PAL) and Graded Naming Test (GNT). Furthermore, analysis through the use of machine learning techniques with regard to the prediction of MCI also obtained encouraging results. This novel simulation was able to predict with about 90% overall accuracy using weighting function proposed to discriminate between MCI and healthy elderly.
24

Isolierung und Charakterisierung funktioneller Exosomen durch sequentielle Filtration

Heinemann, Mitja Leonard 04 October 2016 (has links) (PDF)
Exosomen aus Zellen nehmen eine immer größere Rolle in aktuellen Erkenntnissen zu Tumorwachstum und Metastasierung ein. Die Funktionen dieser circa 40-100 nm großen, aktiv sezernierten Vesikel sind bisher noch weitesgehend ungeklärt. Für die Untersuchung von Exosomen sind optimierte und schonende Isolierungsmethoden notwendig. Zur Zeit gibt es jedoch weder eine standardisierte Methode zur routinemäßigen Isolation von Exosomen noch zur Isolation von funktionell intakten Exosomen für die anschließende Funktionsanalyse. Ziel dieser Arbeit war es, eine vereinfachte, größenbasierte und standardisierbare Methode zur Isolation von funktionell intakten Exosomen zu entwickeln und die isolierten Exosomen qualitativ und quantitativ zu charakterisieren. Die Ergebnisse dieser Arbeit konnten in einer internationalen Fachzeitschrift publiziert werden. Die Publikation liegt dieser Arbeit bei (Heinemann et al. 2014).
25

Conhecimento e práticas de médicos da atenção primária à saúde relacionadas à prevenção do câncer / Primary care physicians\' knowledge and practices related to cancer prevention

Silveira, Tauana Pavanelli do Amaral de Arruda 07 June 2016 (has links)
Introdução: O câncer é uma doença que acomete grande parte da população mundial, sendo o segundo maior responsável pelas mortes no Brasil. A maior parte do cânceres é passível de prevenção e outra grande parte tem altos índices de cura se diagnosticados precocemente. Por isso, o papel dos profissionais de saúde é de fundamental importância para programas eficazes de rastreamento e prevenção do câncer. Objetivos: Avaliar o conhecimento e as práticas de médicos que trabalham em equipes da APS (Estratégia Saúde da Família e Unidades Básicas de Saúde Tradicionais) relacionadas à prevenção do câncer. Material e métodos: Foram realizadas entrevistas com os profissionais da atenção primária: Médicos de Família e Comunidade, Clínicos Gerais e Ginecologistas e Obstetras, vinculados a Unidades de Saúde da Família e Unidades Básicas de Saúde do município de Ribeirão Preto. Os As entrevistas foram realizadas utilizando-se um questionário semi-estruturado, subdividido em 5 partes: dados profissionais, rastreamento do câncer de mama e colo de útero, rastreamento do câncer de cólon e reto, rastreamento do câncer de pulmão e rastreamento de outros tipos de câncer. Resultados: Apesar de afirmarem conhecer as diretrizes de rastreamento de câncer dos principais órgãos nacionais de combate à doença, a análise das práticas referidas pelos entrevistados estava muito aquém daquilo preconizado por essas instituições. Conclusões: Há que se investir em estratégias de conscientização dos profissionais de saúde como um todo (e não apenas os médicos) para o correto aconselhamento de medidas de promoção de saúde relacionada ao câncer, bem como dos exames de rastreamento para o diagnóstico precoce dessas doenças. / Introduction: Cancer is a disease that affects a big part of the world\'s population, and is the second most prevalent cause of death in Brazil. The majority of cancers are preventable and another large part has high rates of cure if diagnosed in early stages. Therefore, the role of health professionals is fundamental for effective cancer prevention and screening programs. Objectives: Evaluate the practices and knowledge of physicians that work in primary health centers (Family Health Strategy Centers and traditional Health Posts) related to cancer prevention. Methodology: Interviews were made with the primary care professionals: family health practitioners, general practitioners and gynecologists and obstetricians, who work at primary health centers in Ribeirão Preto´s local health system. The Interviews were made using a semi-structured questionnaire, divided into 5 parts: professional data, cervical and breast cancer screening, colon and rectal cancer screening, lung cancer screening and screening of other types of cancer. Results: In spite of respondents declare to know the main cancer screening guidelines from the major national institutions for fighting the disease, the analysis of the referred practices of the interviewed participants were too far from what is recommend by those institutions. Conclusion: There is a need to invest in awareness strategies as a whole (and not just the the physicians) for the correct health promotion counseling related to cancer, as well as in the screening tests for early diagnosis of these diseases.
26

Conhecimento e práticas de médicos da atenção primária à saúde relacionadas à prevenção do câncer / Primary care physicians\' knowledge and practices related to cancer prevention

Tauana Pavanelli do Amaral de Arruda Silveira 07 June 2016 (has links)
Introdução: O câncer é uma doença que acomete grande parte da população mundial, sendo o segundo maior responsável pelas mortes no Brasil. A maior parte do cânceres é passível de prevenção e outra grande parte tem altos índices de cura se diagnosticados precocemente. Por isso, o papel dos profissionais de saúde é de fundamental importância para programas eficazes de rastreamento e prevenção do câncer. Objetivos: Avaliar o conhecimento e as práticas de médicos que trabalham em equipes da APS (Estratégia Saúde da Família e Unidades Básicas de Saúde Tradicionais) relacionadas à prevenção do câncer. Material e métodos: Foram realizadas entrevistas com os profissionais da atenção primária: Médicos de Família e Comunidade, Clínicos Gerais e Ginecologistas e Obstetras, vinculados a Unidades de Saúde da Família e Unidades Básicas de Saúde do município de Ribeirão Preto. Os As entrevistas foram realizadas utilizando-se um questionário semi-estruturado, subdividido em 5 partes: dados profissionais, rastreamento do câncer de mama e colo de útero, rastreamento do câncer de cólon e reto, rastreamento do câncer de pulmão e rastreamento de outros tipos de câncer. Resultados: Apesar de afirmarem conhecer as diretrizes de rastreamento de câncer dos principais órgãos nacionais de combate à doença, a análise das práticas referidas pelos entrevistados estava muito aquém daquilo preconizado por essas instituições. Conclusões: Há que se investir em estratégias de conscientização dos profissionais de saúde como um todo (e não apenas os médicos) para o correto aconselhamento de medidas de promoção de saúde relacionada ao câncer, bem como dos exames de rastreamento para o diagnóstico precoce dessas doenças. / Introduction: Cancer is a disease that affects a big part of the world\'s population, and is the second most prevalent cause of death in Brazil. The majority of cancers are preventable and another large part has high rates of cure if diagnosed in early stages. Therefore, the role of health professionals is fundamental for effective cancer prevention and screening programs. Objectives: Evaluate the practices and knowledge of physicians that work in primary health centers (Family Health Strategy Centers and traditional Health Posts) related to cancer prevention. Methodology: Interviews were made with the primary care professionals: family health practitioners, general practitioners and gynecologists and obstetricians, who work at primary health centers in Ribeirão Preto´s local health system. The Interviews were made using a semi-structured questionnaire, divided into 5 parts: professional data, cervical and breast cancer screening, colon and rectal cancer screening, lung cancer screening and screening of other types of cancer. Results: In spite of respondents declare to know the main cancer screening guidelines from the major national institutions for fighting the disease, the analysis of the referred practices of the interviewed participants were too far from what is recommend by those institutions. Conclusion: There is a need to invest in awareness strategies as a whole (and not just the the physicians) for the correct health promotion counseling related to cancer, as well as in the screening tests for early diagnosis of these diseases.
27

Föräldrar och förskolepersonals skattningar av psykisk hälsa hos treåringar

Bolander, Elin, Ahlund, Sofia January 2018 (has links)
Bakgrund: Psykisk ohälsa ökar bland barn och unga och ett av barnhälsovårdens mål är att främja hälsa och utveckling. Tidigare forskning belyser vinsten av tidig upptäckt. I The Strengths and Difficulties Questionnaire (SDQ) upptäcks tecken på psykisk ohälsa genom att svårigheter och styrkor hos barn skattas av föräldrar och förskolepersonal. Föräldrar och förskolepersonal upptäcker svårigheter inom olika områden. En bedömning från både förälder och förskolepersonal ger distriktssköterskan ökad möjlighet att tidigt identifiera ohälsa och initiera åtgärder för att främja hälsa. Syfte: Syftet var att kartlägga föräldrars och förskolepersonals skattning av barns psykiska hälsa genom användning av SDQ i samband med treårsbesök på barnavårdscentral. Metod: Studien är en tvärsnittsstudie med en konsekutiv datainsamling och ett konsekutivt urval. Datan utgörs av skattningar gjorda av föräldrar och förskolepersonal i hälsoformulär som samlats in vid barnets treårsbesök på barnavårdscentralen 2016-01-01 och 2018-06-30. Cohens kappa och Chitvåtest användes som analysmetod. Resultat: Resultaten visade att i SDQ skattades 47 procent av barnen ha svårighet inom någon av dimensionerna som SDQ fångar. Hyperaktivitet-koncentrationsproblem var den dimension som flest treåringarna i studien skattades ha svårigheter i. Resultatet visade en låg överensstämmelse och en signifikant skillnad mellan skattningar gjorda av förskolepersonal och föräldrar. Pojkar skattades oftare med Hyperaktivitet-koncentrationsproblem jämfört med flickor. Slutsats: Skattningar gjorda i SDQ av föräldrar och förskolepersonal kompletterar varandra avseende bedömningen av barns psykiska hälsa i detta material. Tillgång till båda skattningar ger distriktssköterskan i barnhälsovården verktyg i arbetet med att tidigt upptäcka och initiera åtgärder vid psykisk ohälsa för att främja hälsa och utveckling. / Background: Mental health problems are increasing among children and youth. Previous research emphasises the importance of early detection. Signs of mental health and behavior problems can be detected through parents’ and preschool teachers’ assessments using the The Strengths and Difficulties Questionnaire (SDQ). Their assessments identify problems in different areas. Assessment from both parents and preschool teachers may therefore provide the Child Health Services (CHS) a better opportunity to detect early signs of health problems and initiate health promotive measures. Purpose: The aim was to map parents’ and preschool teachers’ assessment of three year old children's mental health problems using the SDQ as part of a broad routine health assessment. Methods: The study had a cross-sectional design, a consecutive data collection method and a consecutive data selection. Data consists of parents’ and preschool teachers’ SDQ assessments collected at the child’s three-year visit in the CHS between 2016-01-01 and 2018-06-30. Cohen´s kappa and Chi Square was used for data analysis. Results: 47 percent of the children were assessed by parents and preschool teachers as having difficulties. Hyperactivity-concentration difficulties were the most common. A low but significant agreement and differences were found between parents’ and preschool teachers’ assessments. Boys were more often assessed as having hyperactivity-concentration difficulties compared with girls. Conclusion: Assessments made by parents and preschool teachers using the SDQ complement each other with respect to children’s behavior in this data set. Access to both assessments provides the CHS-nurse with information that enables early detection and early intervention.
28

Field application of environmental DNA techniques to detect early stages of invasion by the destructive New Zealand mud snail

Woodell, James D. 01 May 2019 (has links)
Nonnative species that cause damage to ecosystems to which they are introduced are considered in-vasive. Restoration of the original ecosystem after an invasive population has established is expensive and difficult but more likely to succeed when invasions are discovered early. Containment efforts to prevent the spread of known invasions also benefit from earlier knowledge of invaded sites. Environ-mental DNA (eDNA) techniques are emerging as a tool that can identify invasive species at a distinctly earlier time point than traditional methods of detection. I collected water samples from eight sites not known to be invaded by the freshwater New Zealand mud snail (NZMS). After filtering these samples to collect eDNA, I used a species-specific probe with qPCR to identify NZMS eDNA. I found evidence for NZMS invasion at five of the eight sites, with later physical confirmation of mud snails at one of these sites. This study is the first example of successful application of eDNA to detect new invasions of the freshwater New Zealand mud snail, setting the stage for further monitoring of at-risk sites to de-tect and control new invasions of this destructive snail.
29

Early Detection and Prevention of Corporate Financial Fraud

Schillermann, Marcia 01 January 2018 (has links)
The economic cost of financial statement fraud continues to be a problem for organizations and society. The research problem addressed in this study was the limited risk management strategies available for the early detection and prevention of financial statement fraud by corporate managers and auditors. These strategies are important to the proactive prevention of fraud. This study is important to future trustworthiness of financial statements. The purpose of this qualitative, multiple-case study was to explore current early detection and prevention methods in financial statement fraud using a risk management conceptual framework. The research question focused on current fraud detection and prevention policies and risk management strategies that are currently used for proactively detecting and preventing financial statement fraud. Multiple sources of information were used, including examining recent financial fraud scandals, interviews, documents, and past research. The target population was managers and auditors of publicly traded corporations. A purposive sampling procedure was used to select 23 participants, which provided rich data. The qualitative data was coded and analyzed using the concept of risk management, along with triangulation to ensure credibility. The key findings indicated that current practitioners are moving beyond the era of reactive measures born from the past fraud crises and are working toward improved financial statement quality and trust. The results of the study also indicated that future research should include proactive methods of preventing fraud. This study is socially significant because it could enhance the ability to trust financial statement reporting in the future and improve corporate reputations.
30

Fuzzy logic based robust control of queue management and optimal treatment of traffic over TCP/IP networks

Li, Zhi January 2005 (has links)
Improving network performance in terms of efficiency, fairness in the bandwidth, and system stability has been a research issue for decades. Current Internet traffic control maintains sophistication in end TCPs but simplicity in routers. In each router, incoming packets queue up in a buffer for transmission until the buffer is full, and then the packets are dropped. This router queue management strategy is referred to as Drop Tail. End TCPs eventually detect packet losses and slow down their sending rates to ease congestion in the network. This way, the aggregate sending rate converges to the network capacity. In the past, Drop Tail has been adopted in most routers in the Internet due to its simplicity of implementation and practicability with light traffic loads. However Drop Tail, with heavy-loaded traffic, causes not only high loss rate and low network throughput, but also long packet delay and lengthy congestion conditions. To address these problems, active queue management (AQM) has been proposed with the idea of proactively and selectively dropping packets before an output buffer is full. The essence of AQM is to drop packets in such a way that the congestion avoidance strategy of TCP works most effectively. Significant efforts in developing AQM have been made since random early detection (RED), the first prominent AQM other than Drop Tail, was introduced in 1993. Although various AQMs also tend to improve fairness in bandwidth among flows, the vulnerability of short-lived flows persists due to the conservative nature of TCP. It has been revealed that short-lived flows take up traffic with a relatively small percentage of bytes but in a large number of flows. From the user’s point of view, there is an expectation of timely delivery of short-lived flows. Our approach is to apply artificial intelligence technologies, particularly fuzzy logic (FL), to address these two issues: an effective AQM scheme, and preferential treatment for short-lived flows. Inspired by the success of FL in the robust control of nonlinear complex systems, our hypothesis is that the Internet is one of the most complex systems and FL can be applied to it. First of all, state of the art AQM schemes outperform Drop Tail, but their performance is not consistent under different network scenarios. Research reveals that this inconsistency is due to the selection of congestion indicators. Most existing AQM schemes are reliant on queue length, input rate, and extreme events occurring in the routers, such as a full queue and an empty queue. This drawback might be overcome by introducing an indicator which takes account of not only input traffic but also queue occupancy for early congestion notification. The congestion indicator chosen in this research is traffic load factor. Traffic load factor is in fact dimensionless and thus independent of link capacity, and also it is easy to use in more complex networks where different traffic classes coexist. The traffic load indicator is a descriptive measure of the complex communication network, and is well suited for use in FL control theory. Based on the traffic load indicator, AQM using FL – or FLAQM – is explored and two FLAQM algorithms are proposed. Secondly, a mice and elephants (ME) strategy is proposed for addressing the problem of the vulnerability of short-lived flows. The idea behind ME is to treat short-lived flows preferably over bulk flows. ME’s operational location is chosen at user premise gateways, where surplus processing resources are available compared to other places. By giving absolute priority to short-lived flows, both short and long-lived flows can benefit. One problem with ME is starvation of elephants or long-lived flows. This issue is addressed by dynamically adjusting the threshold distinguishing between mice and elephants with the guarantee that minimum capacity is maintained for elephants. The method used to dynamically adjust the threshold is to apply FL. FLAQM is deployed to control the elephant queue with consideration of capacity usage of mice packets. In addition, flow states in a ME router are periodically updated to maintain the data storage. The application of the traffic load factor for early congestion notification and the ME strategy have been evaluated via extensive experimental simulations with a range of traffic load conditions. The results show that the proposed two FLAQM algorithms outperform some well-known AQM schemes in all the investigated network circumstances in terms of both user-centric measures and network-centric measures. The ME strategy, with the use of FLAQM to control long-lived flow queues, improves not only the performance of short-lived flows but also the overall performance of the network without disadvantaging long-lived flows.

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