Дисертації з теми "Survival test"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Survival test.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Survival test".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Eklund, Karin, and Malin Engström. "Comparison between two different cryoprotectants for human sperm, with emphasis on survival." Thesis, Uppsala University, Department of Medical Biochemistry and Microbiology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9287.
Повний текст джерелаАнотація:
The increasing number of patients undergoing treatment with assisted reproductive techniques (ART) during the past years have led to the need of developing different methods for separation of spermatozoa that can be used for different fertilisation procedures and for freezing. Cryopreservation of spermatozoa includes preparation, freezing, storage and thawing.
In this study two different cryomedia (Cryo Protec I and Cryo Protec II) for human spermatozoa were compared. The main outcome was spermsurvival rate for spermatozoa after freezing. Sperm viability was assessed using the Hypo-osmotic swelling test which is based on osmolality.
A total of 86 samples of semen were used in this study (Cryo Protec I=38, Cryo Protec II=48). The survival rate between the two cryomedia did not differ much but Cryo Protectant I showed a small increase in survival for the spermatozoa after freezing. The Hypo-osmotic swelling test also showed similar values of viable spermatozoa for the two cryomedia both before and after freezing.
2
Tahir, Muhammad-Ramzan. "On validation of parametric models applied in survival analysis and reliability." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14547/document.
Повний текст джерелаАнотація:
Le premier objectif de la thèse est de présenter un test d'ajustement pour les modèles paramétriques couramment utilisés en l'analyse de survie, la fiabilité, les sciences sociales, l'ingénierie, la santé publique et la démographie, en présence de censure à droite. Nous développons un logiciel en langue R pour les modèles paramétrique. Le modèle de Birnbaum-Saunders (BS) est utilisé pour la test d'ajustement pour les modèles AFT paramétriques et en analyse de système redondant. L'autre contribution porte sur l'analyse de système redondant composé avec une composante en état hot et l'autre en réserve fonctionnent en état warm pour augmenter la fiabilité de systeme. Nous calculons la fiabilité du système en termes de Fonction de répartition et nous donnons l'intervalle de confiance asymptotiqueThis is an increasing importance in survival analysis and reliability to select a suitable basic model for further inquiries of the data. Little deviation in basic model can cause serious problems in final results. The presence of censoring and accelerated stresses make this task more difficult. Chi-square type goodness of fit tests are most commonly used for model selection. Many modifications in chi-square tests have been proposed by various researcher. The first aim of the thesis is to present a goodness of fit test for wide rage of parametric models (shape-scale families) commonly used in survival analysis, social sciences, engineering, public health and demography, in presence of right censoring. We give the explicit forms of the quadratic form of the test statistic (NRR test) for various models and apply the test on real data. We develop a computer program in R-language for all models. A separate section is dedicated for the test in demography. We focus on the Birnbaum-Saunders (BS) distribution for goodness of fit test for parametric AFT-model and analysis of redundant system.The other purpose of the thesis is to give the analysis of redundant system. To ensure high reliability of the main components of the systems, standby units are used. The main component is replaced by the standby unit automatically, if it fails. The standby unit can be in warm, hot, or cold state. We give the procedure of one main and (n-1) standby units placed in hot state, and give the detailed analysis of one main and one standby unit using BS parametric family. We use Sedyakin's physical principal and the approach of accelerated failure time model for the analysis of redundant system. This approach is different from the traditional ones in the literature but difficulties in calculations. We calculate the reliability of the system in terms of distribution function (unreliability function) and asymptotic confidence interval
3
Jubane, Ido. "A simulation study of the behaviour of the logrank test under different levels of stratification and sample sizes." Thesis, University of Fort Hare, 2013. http://hdl.handle.net/10353/d1018558.
Повний текст джерелаАнотація:
In clinical trials, patients are enrolled into two treatment arms. A researcher may be interested in studying the effectiveness of a new drug or the comparison of two drugs for the treatment of a disease. This survival data is later analysed using the logrank test or the Cox regression model to detect differences in survivor functions. However, the power function of the logrank test depends solely on the number of patients enrolled into the study. Because statisticians will always minimise type I and type II errors, a researcher carrying out a clinical trial must define beforehand, the number of patients to be enrolled into the clinical study. Without proper sample size and power estimation a clinical trial may fail to detect a false hypothesis of the equality of survivor functions. This study presents through simulation, a way of power and sample size estimation for clinical trials that use the logrank test for their data analysis and suggests an easy method to estimate power and sample size in such clinical studies. Findings on power analysis and sample size estimation on logrank test are applied to two real examples: one is the Veterans' Administration Lung Cancer study; and the other is the data from a placebo controlled trial of gamma interferon in chronic granulotomous disease.
4
Oller, Piqué Ramon. "Survival analysis issues with interval-censored data." Doctoral thesis, Universitat Politècnica de Catalunya, 2006. http://hdl.handle.net/10803/6520.
Повний текст джерелаАнотація:
L'anàlisi de la supervivència s'utilitza en diversos àmbits per tal d'analitzar dades que mesuren el temps transcorregut entre dos successos. També s'anomena anàlisi de la història dels esdeveniments, anàlisi de temps de vida, anàlisi de fiabilitat o anàlisi del temps fins a l'esdeveniment. Una de les dificultats que té aquesta àrea de l'estadística és la presència de dades censurades. El temps de vida d'un individu és censurat quan només és possible mesurar-lo de manera parcial o inexacta. Hi ha diverses circumstàncies que donen lloc a diversos tipus de censura. La censura en un interval fa referència a una situació on el succés d'interès no es pot observar directament i només tenim coneixement que ha tingut lloc en un interval de temps aleatori. Aquest tipus de censura ha generat molta recerca en els darrers anys i usualment té lloc en estudis on els individus són inspeccionats o observats de manera intermitent. En aquesta situació només tenim coneixement que el temps de vida de l'individu es troba entre dos temps d'inspecció consecutius.Aquesta tesi doctoral es divideix en dues parts que tracten dues qüestions importants que fan referència a dades amb censura en un interval. La primera part la formen els capítols 2 i 3 els quals tracten sobre condicions formals que asseguren que la versemblança simplificada pot ser utilitzada en l'estimació de la distribució del temps de vida. La segona part la formen els capítols 4 i 5 que es dediquen a l'estudi de procediments estadístics pel problema de k mostres. El treball que reproduïm conté diversos materials que ja s'han publicat o ja s'han presentat per ser considerats com objecte de publicació.
En el capítol 1 introduïm la notació bàsica que s'utilitza en la tesi doctoral. També fem una descripció de l'enfocament no paramètric en l'estimació de la funció de distribució del temps de vida. Peto (1973) i Turnbull (1976) van ser els primers autors que van proposar un mètode d'estimació basat en la versió simplificada de la funció de versemblança. Altres autors han estudiat la unicitat de la solució obtinguda en aquest mètode (Gentleman i Geyer, 1994) o han millorat el mètode amb noves propostes (Wellner i Zhan, 1997).
El capítol 2 reprodueix l'article d'Oller et al. (2004). Demostrem l'equivalència entre les diferents caracteritzacions de censura no informativa que podem trobar a la bibliografia i definim una condició de suma constant anàloga a l'obtinguda en el context de censura per la dreta. També demostrem que si la condició de no informació o la condició de suma constant són certes, la versemblança simplificada es pot utilitzar per obtenir l'estimador de màxima versemblança no paramètric (NPMLE) de la funció de distribució del temps de vida. Finalment, caracteritzem la propietat de suma constant d'acord amb diversos tipus de censura. En el capítol 3 estudiem quina relació té la propietat de suma constant en la identificació de la distribució del temps de vida. Demostrem que la distribució del temps de vida no és identificable fora de la classe dels models de suma constant. També demostrem que la probabilitat del temps de vida en cadascun dels intervals observables és identificable dins la classe dels models de suma constant. Tots aquests conceptes els
il·lustrem amb diversos exemples.
El capítol 4 s'ha publicat parcialment en l'article de revisió metodològica de Gómez et al. (2004). Proporciona una visió general d'aquelles tècniques que s'han aplicat en el problema no paramètric de comparació de dues o més mostres amb dades censurades en un interval. També hem desenvolupat algunes rutines amb S-Plus que implementen la versió permutacional del tests de Wilcoxon, Logrank i de la t de Student per a dades censurades en un interval (Fay and Shih, 1998). Aquesta part de la tesi doctoral es complementa en el capítol 5 amb diverses propostes d'extensió del test de Jonckeere. Amb l'objectiu de provar una tendència en el problema de k mostres, Abel (1986) va realitzar una de les poques generalitzacions del test de Jonckheere per a dades censurades en un interval. Nosaltres proposem altres generalitzacions d'acord amb els resultats presentats en el capítol 4. Utilitzem enfocaments permutacionals i de Monte Carlo. Proporcionem programes informàtics per a cada proposta i realitzem un estudi de simulació per tal de comparar la potència de cada proposta sota diferents models paramètrics i supòsits de tendència. Com a motivació de la metodologia, en els dos capítols s'analitza un conjunt de dades d'un estudi sobre els beneficis de la zidovudina en pacients en els primers estadis de la infecció del virus VIH (Volberding et al., 1995).
Finalment, el capítol 6 resumeix els resultats i destaca aquells aspectes que s'han de completar en el futur.
Survival analysis is used in various fields for analyzing data involving the duration between two events. It is also known as event history analysis, lifetime data analysis, reliability analysis or time to event analysis. One of the difficulties which arise in this area is the presence of censored data. The lifetime of an individual is censored when it cannot be exactly measured but partial information is available. Different circumstances can produce different types of censoring. Interval censoring refers to the situation when the event of interest cannot be directly observed and it is only known to have occurred during a random interval of time. This kind of censoring has produced a lot of work in the last years and typically occurs for individuals in a study being inspected or observed intermittently, so that an individual's lifetime is known only to lie between two successive observation times.
This PhD thesis is divided into two parts which handle two important issues of interval censored data. The first part is composed by Chapter 2 and Chapter 3 and it is about formal conditions which allow estimation of the lifetime distribution to be based on a well known simplified likelihood. The second part is composed by Chapter 4 and Chapter 5 and it is devoted to the study of test procedures for the k-sample problem. The present work reproduces several material which has already been published or has been already submitted.
In Chapter 1 we give the basic notation used in this PhD thesis. We also describe the nonparametric approach to estimate the distribution function of the lifetime variable. Peto (1973) and Turnbull (1976) were the first authors to propose an estimation method which is based on a simplified version of the likelihood function. Other authors have studied the uniqueness of the solution given by this method (Gentleman and Geyer, 1994) or have improved it with new proposals (Wellner and Zhan, 1997).
Chapter 2 reproduces the paper of Oller et al. (2004). We prove the equivalence between different characterizations of noninformative censoring appeared in the literature and we define an analogous constant-sum condition to the one derived in the context of right censoring. We prove as well that when the noninformative condition or the constant-sum condition holds, the simplified likelihood can be used to obtain the nonparametric maximum likelihood estimator (NPMLE) of the failure time distribution function. Finally, we characterize the constant-sum property according to different types of censoring. In Chapter 3 we study the relevance of the constant-sum property in the identifiability of the lifetime distribution. We show that the lifetime distribution is not identifiable outside the class of constant-sum models. We also show that the lifetime probabilities assigned to the observable intervals are identifiable inside the class of constant-sum models. We illustrate all these notions with several examples.
Chapter 4 has partially been published in the survey paper of Gómez et al. (2004). It gives a general view of those procedures which have been applied in the nonparametric problem of the comparison of two or more interval-censored samples. We also develop some S-Plus routines which implement the permutational version of the Wilcoxon test, the Logrank test and the t-test for interval censored data (Fay and Shih, 1998). This part of the PhD thesis is completed in Chapter 5 by different proposals of extension of the Jonckeere's test. In order to test for an increasing trend in the k-sample problem, Abel (1986) gives one of the few generalizations of the Jonckheree's test for interval-censored data. We also suggest different Jonckheere-type tests according to the tests presented in Chapter 4. We use permutational and Monte Carlo approaches. We give computer programs for each proposal and perform a simulation study in order compare the power of each proposal under different parametric assumptions and different alternatives. We motivate both chapters with the analysis of a set of data from a study of the benefits of zidovudine in patients in the early stages of the HIV infection (Volberding et al., 1995).
Finally, Chapter 6 summarizes results and address those aspects which remain to be completed.
5
Bagdonavičius, Vilijandas B., Ruta Levuliene, Mikhail S. Nikulin, and Olga Zdorova-Cheminade. "Tests for homogeneity of survival distributions against non-location alternatives and analysis of the gastric cancer data." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2011/5152/.
Повний текст джерелаАнотація:
The two and k-sample tests of equality of the survival distributions against
the alternatives including cross-effects of survival functions, proportional and monotone hazard ratios, are given for the right censored data. The asymptotic power against approaching alternatives is investigated. The tests are applied to the well known chemio and radio therapy data of the Gastrointestinal Tumor Study Group. The P-values for both proposed tests are much smaller then in the case of other known tests. Differently from the test of Stablein and Koutrouvelis the new tests can be applied not only for singly but also to randomly censored data.
6
Liang, Yi. "Likelihood ratio test for the presence of cured individuals : a simulation study /." Internet access available to MUN users only, 2002. http://collections.mun.ca/u?/theses,157472.
Повний текст джерела
7
Lauth, John R. "Development of methodology for community level toxicity testing using the fathead minnow seven day survival-growth impairment test." Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/39417.
Повний текст джерелаАнотація:
Single species toxicity tests are widely used to assess the potential effects of a toxicant on aquatic life. Increasingly, it is necessary to understand how the results of these tests relate to toxicant effects in natural communities. This dissertation presents the methodology and validation for a community level toxicity test that bridges the gap between single species tests and natural community responses. The research involved control of environmental parameters, improvement of feeding regimes and testing of the final community. The results are presented as four separate papers.
The first paper addresses the development and validation of a standardized reconstituted water for culturing and toxicity testing of algae, cladocerans, a rotifer and two fish species. The next two papers address the substitution of the food source currently used in the fathead minnow survival-growth impairment test (Artemia) with a freshwater food source (the rotiter, Brachionus calyciflorus). Along with the alga Chlorella vulgaris (producer), B. calyciflorus (primary consumer) and the fathead minnow larvae (secondary consumer) comprise a three level food chain that was used to address trophic level interactions (feeding reduction and growth impairment) in the final phase of this research. The end result is an experimental procedure in which environmental parameters (water quality, temperature, etc.) and trophic structure parameters (Le. producer and primary consumer density) can be controlled well enough to insure that any shifts in community structure can be attributed to toxicant related effects.Ph. D.
8
Mai, Yabing. "Comparing survival distributions in the presence of dependent censoring asymptotic validity and bias-corrections of the logrank test /." College Park, Md. : University of Maryland, 2008. http://hdl.handle.net/1903/8037.
Повний текст джерелаАнотація:
Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Mathematics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
9
Morris, Jesse Randal. "Methods and Application for Tracking Seedling Fate on the Utah Test and Training Range." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/9102.
Повний текст джерелаАнотація:
Remote sensing of the environment has become an effective and useful research approach applied across a wide range of scientific and professional disciplines. Generally remote sensing is used to evaluate patterns and processes at broad spatio-temporal scales, such as classifying landscape vegetation patterns or for creating digital surface models, however, there are increasing opportunities to expand the use of remotely sensed information to a wider range of applications at variable spatial and temporal scales. In the field of plant seedling and germination research methods are needed to improve plant establishment and restoration monitoring, particularly in areas that have historically low success rates such as in semi-arid and arid rangeland landscapes. The purpose of this research is to assess the efficacy of remote sensing for tracking seedling height, seedling density, and seedling fate, and determine the biotic causes of seedling mortality in a rangeland revegetation site in northwestern Utah. In Chapter 1, we use 28 time-lapse and motion sensing infrared cameras (Reconyx) to measure seedling density and height in fenced and unfenced plots during the initial four months of seedling establishment and growth. We compare imaged-based measurements of seedling height and density with similar measurements collected in the field and at different daylight hours to determine the accuracy and reliability of remotely sensed measurements. We found that the ideal sample periods for capturing the clearest images were at the time the sun passed zenith and shadows were minimized. Average seedling height was 14% lower in image-based versus field estimates. Seedling density was underestimated by approximately 30% when using cameras. Our study establishes that remote sensing of seedlings using time-lapse cameras is a method for seedling research and monitoring in restoration efforts which merits further research and development. In Chapter 2, we track biotic causes of seedling fate using the methods developed in Chapter 1, and compare seedling survival in fenced and unfenced plots. Fencing led to a four-fold increase in the number of seedlings emerged from the soil. Herbivory and damage caused by trampling and burial resulted in the death of 61.4 % of all unfenced seedlings. Fencing plots increased the probability of seedling survival by seven times. Using cameras to track seedling fate at two restoration sites revealed that small herbivores, including Lepus californicus, Thomomys bottae, and Dipodomys sp. drastically reduced seedling survival during the first year after planting. Effects of herbivores on seedling survival should be taken into consideration when planning revegetation operations, and further research can increase knowledge of how herbivory affects restoration efforts. Using cameras can provide meaningful information to managers and researchers about seedling status and fate.
10
Rückbeil, Marcia Viviane [Verfasser], Ralf-Dieter Akademischer Betreuer] Hilgers, and Klaus [Akademischer Betreuer] [Willmes. "The impact of bias on test decisions in survival analysis / Marcia Viviane Rückbeil ; Ralf-Dieter Hilgers, Klaus Willmes-von Hinckeldey." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1220729183/34.
Повний текст джерела
11
Rückbeil, Marcia Viviane Verfasser], Ralf-Dieter [Akademischer Betreuer] Hilgers, and Klaus [Akademischer Betreuer] [Willmes. "The impact of bias on test decisions in survival analysis / Marcia Viviane Rückbeil ; Ralf-Dieter Hilgers, Klaus Willmes-von Hinckeldey." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1220729183/34.
Повний текст джерела
12
Teixeira, Juliana Cecilia da Silva. "Testes de superioridade para modelos de chances proporcionais com e sem fração de cura." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/104/104131/tde-16022018-104100/.
Повний текст джерелаАнотація:
Estudos que comprovem a superioridade de um fármaco em relação a outros já existentes no mercado são de grande interesse na prática clínica. Através deles a Agência Nacional de Vigilância Sanitária (ANVISA) concede registro a novos produtos, que podem curar mais rápido ou aumentar a probabilidade de cura dos pacientes, em comparação ao tratamento padrão. É de suma importância que os testes de hipóteses controlem a probabilidade do erro tipo I, ou seja, controlem a probabilidade de que um tratamento não superior seja aprovado para uso; e também atinja o poder de teste regulamentado com o menor número de indivíduos possível. Os testes de hipóteses existentes para esta finalidade ou desconsideram o tempo até que o evento de interesse ocorra (reação alérgica, efeito positivo, etc) ou são baseados no modelo de riscos proporcionais. No entanto, na prática, a hipótese de riscos proporcionais pode nem sempre ser satisfeita, como é o caso de ensaios cujos riscos dos diferentes grupos em estudo se igualam com o passar do tempo. Nesta situação, o modelo de chances proporcionais é mais adequado para o ajuste dos dados. Neste trabalho desenvolvemos e investigamos dois testes de hipóteses para ensaios clínicos de superioridade, baseados na comparação de curvas de sobrevivência sob a suposição de que os dados seguem o modelo de chances de sobrevivências proporcionais, um sem a incorporação da fração de cura e outro com esta incorporação. Vários estudos de simulação são conduzidos para analisar a capacidade de controle da probabilidade do erro tipo I e do valor do poder dos testes quando os dados satisfazem ou não a suposição do teste para diversos tamanhos amostrais e dois métodos de estimação das quantidades de interesse. Concluímos que a probabilidade do erro tipo I é subestimada quando os dados não satisfazem a suposição do teste e é controlada quando satisfazem, como esperado. De forma geral, concluímos que é imprescindível satisfazer as suposições dos testes de superioridade.Studies that prove the superiority of a drug in relation to others already existing in the market are of great interest in clinical practice. Based on them the Brazilian National Agency of Sanitary Surveillance (ANVISA) grants superiority drugs registers which can cure faster or increase the probability of cure of patients, compared to standard treatment. It is of the utmost importance that hypothesis tests control the probability of type I error, that is, they control the probability that a non-superior treatment is approved for use; and also achieve the test power regulated with as few individuals as possible. Tests of hypotheses existing for this purpose or disregard the time until the event of interest occurrence (allergic reaction, positive effect, etc.) or are based on the proportional hazards model. However, in practice, the hypothesis of proportional hazards may not always be satisfied, as is the case of trials whose risks of the different study groups become equal over time. In this situation, the proportional odds survival model is more adequate for the adjustment of the data. In this work we developed and investigated two hypothesis tests for clinical trials of superiority, based on the comparison of survival curves under the assumption that the data follow the proportional survival odds model, one without the incorporation of cure fraction and another considering cure fraction. Several simulation studies are conducted to analyze the ability to control the probability of type I error and the value of the power of the tests when the data satisfy or not the assumption of the test for different sample sizes and two estimation methods of the quantities of interest. We conclude that the probability of type I error is underestimated when the data do not satisfy the assumption of the test and it is controlled when they satisfy, as expected. In general, we conclude that it is indispensable to satisfy the assumptions of superiority tests.
13
Messager, Syndie. "Development of an 'ex-vivo' test to study microbial survival on human skin and the antimicrobial efficacy of formulations with antiseptic properties." Thesis, University of London, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496750.
Повний текст джерела
14
Oliveira, Jocelânio Wesley de. "Gráficos de controle CUSUM para monitoramento de dados de sobrevivência." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-23072018-124341/.
Повний текст джерелаАнотація:
Neste trabalho propomos gráficos de controle tipo CUSUM para monitoramento de tempos de sobrevivência. Nossa proposta é desenvolver diferentes estatísticas para o escore do gráfico CUSUM de forma prospectiva. Inicialmente propomos um gráfico CUSUM não paramétrico para monitoramento de populações homogêneas que avalia a variação na estatística log-rank como forma de identificar se há uma mudança significativa no risco de falha ao longo do tempo. Algumas abordagens diferentes foram consideradas e em destaque colocamos o gráfico ZDiff CUSUM, que tem como escore o incremento na estatística Z do teste log-rank em relação à inspeção anterior. Foi constatado, via simulação, que este método é eficiente. Posteriormente investigamos abordagens que levam em conta heterogeneidade na população por meio do modelo de Cox, considerando medidas baseadas na razão de verossimilhanças e em resíduos martingal e deviance. Através de simulações, verificou-se que o método com base na razão de verossimilhanças se mostrou ágil para detectar alteração na taxa de falha, quando se conhece a intensidade da mudança e este valor é informado na construção do teste. Por outro lado, os gráficos CUSUM com base em resíduos são mais simples e se mostraram eficazes para identificar aumentos no padrão da sobrevivência. Estes três métodos e o ZDiff CUSUM foram aplicados a dados de um estudo conduzido no Instituto do Coração (InCor) envolvendo pacientes com insuficiência cardíaca. Foi detectado que ao longo do tempo estes pacientes apresentam sobrevida maior, o que pode estar ligado à melhoria no tratamento e procedimentos realizados no hospital. Como conclusão, sugerimos que os gráficos tipo CUSUM com resíduos do modelo de Cox e o método não paramétrico com teste log-rank podem ser alternativas para utilização na prática em monitoramento de dados de sobrevivência.In this work we propose CUSUM control charts to monitor survival times. Our proposal is to develop different statistics for the CUSUM chart score in a prospective way, to take into account SA approaches. We initially consider a non-parametric approach to monitor homogeneous populations. This CUSUM evaluates the variation on the log-rank test statistics as a way to identify significant changes in the risk of failure. Some different expressions for this have been considered and, in particular, we propose a ZDiff CUSUM chart computed as the increment on the log-rank test statistics Z at each inspection point in relation to the previous one. Based on simulation studies it was found that this method is efficient. Subsequently we investigated approaches that take into account heterogeneity in the population through the Cox model, considering measures based on the likelihood ratio and on martingal and deviance residuals. Through simulations, it was verified that the method based on the likelihood ratio was agile to detect a change in the hazard rate, when the intensity of the change is known and this value is informed in the construction of the test. On the other hand, CUSUM methods based on residuals are simpler and have been shown to be effective in identifying increases in survival pattern. These three methods and the ZDiff CUSUM were applied to a dataset from a study conducted at the Heart Institute (InCor) on patients with heart failure. It has been found that, over time, these patients have greater survival, which may be linked to improved treatment and procedures performed at the hospital. As a conclusion, we suggest that the CUSUM methods based on Cox model residuals and the nonparametric method on the log-rank test may be alternatives for practice in monitoring survival data.
15
Nord, Anette. "Bystander CPR : New aspects of CPR training among students and the importance of bystander education level on survival." Doctoral thesis, Linköpings universitet, Avdelningen för kardiovaskulär medicin, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-142460.
Повний текст джерелаАнотація:
Background: It has been proved that bystander cardiopulmonary resuscitation (CPR) saves lives; however, which training method in CPR is most instructive and whether survival is affected by the training level of the bystander have not yet been fully described. Aim: To identify the factors that may affect 7th grade students’ acquisition of CPR skills during CPR training and their willingness to act, and to describe 30-day survival from outof- hospital cardiac arrest (OHCA) after bystander CPR and the actions performed by laymen versus off-duty medically educated personnel. Methods: Studies I–III investigate a CPR training intervention given to students in 7th grade during 2013–2014. The classes were randomized to the main intervention: the mobile phone application (app) or DVD-based training. Some of the classes were randomized to one or several additional interventions: a practical test with feedback, reflection, a web course, a visit from elite athletes and automated external defibrillator (AED) training. The students’ practical skills, willingness to act and knowledge of stroke symptoms, symptoms of acute myocardial infarction (AMI) and lifestyle factors were assessed directly after training and at 6 months using the Laerdal PC SkillReporting system (and entered into a modified version of the Cardiff test scoring sheet) and a questionnaire. The Cardiff test resulted in a total score of 12–48 points, and the questionnaire resulted in a total score of 0–7 points for stroke symptoms, 0–9 points for symptoms of AMI and 0– 6 points on lifestyle factors. Study IV is based on retrospective data from the national quality register, the Swedish registry of cardiopulmonary resuscitation, 2010-2014. Results: A total of 1339 students were included in the CPR training intervention. The DVD-based group was superior to the app-based group in CPR skills, with a total score of 35 (SD 4.o) vs 33 (SD 4.2) points directly after training (p<0.001) and 33 (SD 4.0) vs 31 (SD 4.2) points at six months (p<0.001). Of the additional interventions, the practical test with feedback had the greatest influence regarding practical skills: at six months the intervention group scored 32 (SD 3.9) points and the control group (CPR only) scored 30 (SD 4.0) points (p<0.001). Reflection, the web course, visits from elite athletes and AED training did not further increase the students’ acquisition of practical CPR skills. The students who completed the web course Help-Brain-Heart received a higher total score for theoretical knowledge in comparison with the control group, directly after training: stroke 3.8 (SD 1.8) vs 2.7 (SD 2.0) points (p<0.001); AMI 4.0 (SD 2.0) vs 2.5 (SD 2.0) points (p<0.001); lifestyle factors 5.4 (SD 1.2) vs 4.5 (SD 2.0) points p<0.001. Most of the students (77% at 6 months), regardless of the intervention applied, expressed that they would perform both chest compressions and ventilations in a cardiac arrest (CA) situation involving a relative. If a stranger had CA, a significantly lower proportion of students (32%; p<0.001) would perform both compressions and ventilations. In this case, however, many would perform compressions only. In most cases of bystander-witnessed OHCA, CPR was performed by laymen. Off-duty health care personnel bystanders initiated CPR within 1 minute vs 2 minutes for laymen (p<0.0001). Thirty-day survival was 14.7% among patients who received CPR from laymen and 17.2% (p=0.02) among patients who received bystander CPR from off-duty health care personnel. Conclusions: The DVD-based method was superior to the app-based method in terms of teaching practical CPR skills to 7th grade students. Of the additional interventions, a practical test with feedback was the most efficient intervention to increase learning outcome. The additional interventions, reflection, web course, visit from elite athletes and AED did not increase CPR skills further. However, the web course Help-Brain-Heart improved the students’ acquisition of theoretical knowledge regarding stroke, AMI and lifestyle factors. For OHCA, off-duty health care personnel bystanders initiated CPR earlier and 30-day survival was higher compared with laymen bystanders.
16
Fei, Mingwei. "A study of the robustness of Cox's proportional hazards model used in testing for covariate effects." Kansas State University, 2012. http://hdl.handle.net/2097/13528.
Повний текст джерелаАнотація:
Master of ArtsDepartment of Statistics
Paul Nelson
There are two important statistical models for multivariate survival analysis, proportional hazards(PH) models and accelerated failure time(AFT) model. PH analysis is most commonly used multivariate approach for analysing survival time data. For example, in clinical investigations where several (known) quantities or covariates, potentially affect patient prognosis, it is often desirable to investigate one factor effect adjust for the impact of others. This report offered a solution to choose appropriate model in testing covariate effects under different situations. In real life, we are very likely to just have limited sample size and censoring rates(people dropping off), which cause difficulty in statistical analysis. In this report, each dataset is randomly repeated 1000 times from three different distributions (Weibull, Lognormal and Loglogistc) with combination of sample sizes and censoring rates. Then both models are evaluated by hypothesis testing of covariate effect using the simulated data using the derived statistics, power, type I error rate and covergence rate for each situation. We would recommend PH method when sample size is small(n<20) and censoring rate is high(p>0.8). In this case, both PH and AFT analyses may not be suitable for hypothesis testing, but PH analysis is more robust and consistent than AFT analysis. And when sample size is 20 or above and censoring rate is 0.8 or below, AFT analysis will have slight higher convergence rate and power than PH, but not much improvement in Type I error rates when sample size is big(n>50) and censoring rate is low(p<0.3). Considering the privilege of not requiring knowledge of distribution for PH analysis, we concluded that PH analysis is robust in hypothesis testing for covariate effects using data generated from an AFT model.
17
Graffeo, Nathalie. "Méthodes d'analyse de la survie nette : utilisation des tables de mortalité, test de comparaison et détection d'agrégats spatiaux." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM5067/document.
Повний текст джерелаАнотація:
La survie nette, indicateur clé de l'efficacité des systèmes de soin dans la lutte contre le cancer, est un concept théorique représentant la survie que l'on observerait dans un monde hypothétique où le cancer étudié serait la seule cause de décès. En s'affranchissant de la mortalité due aux causes autres que ce cancer, elle permet des comparaisons entre populations. Dans cette thèse, après présentation du concept et des méthodes d'estimation de la survie nette quand la cause de décès est inconnue, nous étudions trois problématiques. La première porte sur les tables de mortalité utilisées pour estimer la survie nette. En France, ces tables sont stratifiées sur âge, sexe, année et département. Il serait intéressant d'utiliser des tables stratifiées sur d'autres facteurs impactant la mortalité. Nous étudions l'impact du manque de stratification sur les estimations des effets des facteurs pronostiques sur la mortalité en excès (celle due au cancer en l'absence des autres causes de décès) par des études de simulations et sur données réelles. La deuxième problématique porte sur la construction d'un test de type log-rank pour comparer des distributions de survie nette estimées par l'estimateur Pohar-Perme, estimateur non paramétrique consistant de la survie nette. Notre troisième problématique est de déterminer dans une aire géographique des zones différentes en termes de survie nette. Nous adaptons une méthode de détection de clusters à la survie nette en utilisant le test précédemment développé comme critère de découpage. Ce travail propose ainsi des développements et outils nouveaux pour étudier et améliorer la qualité de la prise en charge des patients atteints d'un cancerIn cancer research, net survival is a key indicator of health care efficiency. This theoretical concept is the survival that would be observed in an hypothetical world where the disease under study would be the only possible cause of death. In population-based studies, where cause of death is unknown, net survival allows to compare net cancer survival between different groups by removing the effect of death from causes other than cancer. In this work, after presenting the concept and the estimation methods of net survival, we focus on three complementary issues. The first one is about the life tables used in the estimates of net survival. In France, these tables are stratified by age, sex, year and département. Other prognostic factors impact on mortality. So it would be interesting to use life tables stratified by some of these factors. We study the impact of the lack of stratification in life tables on the estimates of the effects of prognostic factors on excess mortality by simulations and real data studies. In 2012, the Pohar-Perme estimator was proposed. It is a consistent non parametric estimator of net survival. The second issue involves the building of a log-rank type test to compare distributions of net survival (estimated by the Pohar-Perme estimator) between several groups. Our third issue is to propose a method providing potential spatial clusters which could contain patients with similar net cancer survival rates. We adapt a clustering method using the test we have built as a splitting criterion. This work proposes new developments and new tools to study and improve the quality of care for cancer patients. These methods are suitable to other chronic diseases
18
Carneiro, H?rica Priscila de Ara?jo. "Testes de hip?teses em modelos de sobreviv?ncia com Fra??o de cura." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/18644.
Повний текст джерелаАнотація:
Made available in DSpace on 2015-03-03T15:28:33Z (GMT). No. of bitstreams: 1
HericaPAC_DISSERT.pdf: 752483 bytes, checksum: c4526cc225ac72a39965ad5818e0e718 (MD5)
Previous issue date: 2012-08-14Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Survival models deals with the modeling of time to event data. However in some situations part of the population may be no longer subject to the event. Models that take this fact into account are called cure rate models. There are few studies about hypothesis tests in cure rate models. Recently a new test statistic, the gradient statistic, has been proposed. It shares the same asymptotic properties with the classic large sample tests, the likelihood ratio, score and Wald tests. Some simulation studies have been carried out to explore the behavior of the gradient statistic in fi nite samples and compare it with the classic statistics in diff erent models. The main objective of this work is to study and compare the performance of gradient test and likelihood ratio test in cure rate models. We first describe the models and present the main asymptotic properties of the tests. We perform a simulation study based on the promotion time model with Weibull distribution to assess the performance of the tests in finite samples. An application is presented to illustrate the studied concepts
Modelos de sobreviv?ncia tratam do estudo do tempo at? a ocorr?ncia de um evento. Contudo em algumas situa??es, uma propor??o da popula??o pode n?o estar mais sujeita a ocorr?ncia deste evento. Modelos que tratam desta abordagem s?o chamados de modelos de fra??o de cura. Existem poucos estudos na literatura sobre testes de hip?teses aplicados a modelos de fra??o de cura. Recentemente foi proposta uma nova estat?stica de teste, denominada estat?stica gradiente que possui distribui??o assint?tica equivalente a das estat?sticas usuais. Alguns estudos de simula??o v?m sendo desenvolvidos no sentido de explorar caracter?sticas dessa nova estat?stica e comparar com as estat?sticas cl?ssicas, aplicadas a diferentes modelos. Este trabalho tem como principal objetivo estudar e comparar o desempenho do teste gradiente e do teste da raz?o de verossimilhan?as, em modelos de fra??o de cura. Para isso descrevemos caracter?sticas do modelo e apresentamos os principais resultados assint?ticos dos testes. Consideramos um estudo de simula??o com base no modelo de tempo de promo??o com distribui??o Weibull, para avaliar o desempenho dos testes em amostras finitas. Uma aplica??o e realizada para ilustrar os conceitos estudados
19
鄧雅恩 and Nga-yan Fancy Tang. "Resampling tests for some survival models." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31226759.
Повний текст джерела
20
Tang, Nga-yan Fancy. "Resampling tests for some survival models /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23457338.
Повний текст джерела
21
He, Bin. "APPLICATION OF THE EMPIRICAL LIKELIHOOD METHOD IN PROPORTIONAL HAZARDS MODEL." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4384.
Повний текст джерелаАнотація:
In survival analysis, proportional hazards model is the most commonly used and the Cox model is the most popular. These models are developed to facilitate statistical analysis frequently encountered in medical research or reliability studies. In analyzing real data sets, checking the validity of the model assumptions is a key component. However, the presence of complicated types of censoring such as double censoring and partly interval-censoring in survival data makes model assessment difficult, and the existing tests for goodness-of-fit do not have direct extension to these complicated types of censored data. In this work, we use empirical likelihood (Owen, 1988) approach to construct goodness-of-fit test and provide estimates for the Cox model with various types of censored data. Specifically, the problems under consideration are the two-sample Cox model and stratified Cox model with right censored data, doubly censored data and partly interval-censored data. Related computational issues are discussed, and some simulation results are presented. The procedures developed in the work are applied to several real data sets with some discussion.Ph.D.
Department of Mathematics
Sciences
Mathematics
22
Pecková, Monika. "Efficiency based adaptive tests for censored survival data /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9599.
Повний текст джерела
23
Ye, Hong. "Comparison of Cox regression and discrete time survival models." Thesis, Wayne State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10153426.
Повний текст джерелаАнотація:
A standard analysis of prostate cancer biochemical failure data is done by conducting two approaches in which risk factors or covariates are measured. Cox regression and discrete-time survival models were compared under different attributes: sample size, time periods, and parameters in the model. The person-period data was reconstructed when examining the same data in discrete-time survival model. Twenty-four numerical examples covering a variety of sample sizes, time periods, and number of parameters displayed the closeness of Cox regression and discrete-time survival methods in situations typical of the cancer study.
24
Perdona, Gleici da Silva Castro. "Modelos de riscos aplicados à análise de sobrevivência." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-07112006-135528/.
Повний текст джерелаАнотація:
Assumir suposições especiais sobre a função de risco tem sido a estratégia adotada por vários autores, com intuito de garantir modelos gerais e abrangentes, tanto para a análise de dados de sobrevivência quanto de conDabilidade. Neste estudo, modelos aplicados a dados da área de sobrevivência e conDabilidade são considerados. A Dnalidade deste estudo é propor modelos mais Pexíveis e/ou mais abrangentes de forma a generalizar modelos já existentes, bem como estudar suas propriedades e propor possíveis comparações entre os modelos via testes de hipóteses. Considera-se nesta tese, três classes de modelos baseados na função de risco (modelos de risco). A primeira classe apresenta-se como um caso particular do modelo de risco estendido (Louzada-Neto, 1999), formada por modelos que relacionam o parâmetro de escala a covariáveis, sendo que esse relacionamento pode ser considerado log-linear ou log-nãolinear. Considera-se um modelo particular onde a dependência do parâmetro de escala se dá de forma log-não-linear. Na segunda classe considera-se modelos que estão vinculados a dados de riscos competitivos, quando se tem ou não informação sobre qual tipo de risco foi responsável pela falha de um equipamento ou pelo óbito de um paciente. A terceira classe de modelos foi proposta, nesta tese, relacionando o contexto de modelos de longa duração.Assuming special suppositions for the hazard function have been the strategy used for many authors in order to guarantee general and Pexible models for survival and reliability data. The present thesis considers two classes of hazard models, with the basic objective of proposing more Pexible models, studying their properties and proposing possible comparisons via hypothesis tests. We consider, three families of models where the struture was based in hazard function. The Drst class is a special case of the extented hazard model (Louzada, 1999). This class of models is composed by models with relationship between the scale parameter and the covariates could be log-linear or log-non-linear, we consider the log-non-linear. The second class is into the context of competing risk, where we do not known what kind of risk is responsable for the fail.or death. The third class, proposed in this work refers to a context of long term survivals. All the procedures were ilustrated in real datasets
25
Tran, Xuan Quang. "Les modèles de régression dynamique et leurs applications en analyse de survie et fiabilité." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0147/document.
Повний текст джерелаАнотація:
Cette thèse a été conçu pour explorer les modèles dynamiques de régression, d’évaluer les inférences statistiques pour l’analyse des données de survie et de fiabilité. Ces modèles de régression dynamiques que nous avons considérés, y compris le modèle des hasards proportionnels paramétriques et celui de la vie accélérée avec les variables qui peut-être dépendent du temps. Nous avons discuté des problèmes suivants dans cette thèse.Nous avons présenté tout d’abord une statistique de test du chi-deux généraliséeY2nquiest adaptative pour les données de survie et fiabilité en présence de trois cas, complètes,censurées à droite et censurées à droite avec les covariables. Nous avons présenté en détailla forme pratique deY2nstatistique en analyse des données de survie. Ensuite, nous avons considéré deux modèles paramétriques très flexibles, d’évaluer les significations statistiques pour ces modèles proposées en utilisantY2nstatistique. Ces modèles incluent du modèle de vie accélérés (AFT) et celui de hasards proportionnels (PH) basés sur la distribution de Hypertabastic. Ces deux modèles sont proposés pour étudier la distribution de l’analyse de la duré de survie en comparaison avec d’autre modèles paramétriques. Nous avons validé ces modèles paramétriques en utilisantY2n. Les études de simulation ont été conçus.Dans le dernier chapitre, nous avons proposé les applications de ces modèles paramétriques à trois données de bio-médicale. Le premier a été fait les données étendues des temps de rémission des patients de leucémie aiguë qui ont été proposées par Freireich et al. sur la comparaison de deux groupes de traitement avec des informations supplémentaires sur les log du blanc du nombre de globules. Elle a montré que le modèle Hypertabastic AFT est un modèle précis pour ces données. Le second a été fait sur l’étude de tumeur cérébrale avec les patients de gliome malin, ont été proposées par Sauerbrei & Schumacher. Elle a montré que le meilleur modèle est Hypertabastic PH à l’ajout de cinq variables de signification. La troisième demande a été faite sur les données de Semenova & Bitukov, à concernant les patients de myélome multiple. Nous n’avons pas proposé un modèle exactement pour ces données. En raison de cela était les intersections de temps de survie.Par conséquent, nous vous conseillons d’utiliser un autre modèle dynamique que le modèle de la Simple Cross-Effect à installer ces donnéesThis thesis was designed to explore the dynamic regression models, assessing the sta-tistical inference for the survival and reliability data analysis. These dynamic regressionmodels that we have been considered including the parametric proportional hazards andaccelerated failure time models contain the possibly time-dependent covariates. We dis-cussed the following problems in this thesis.At first, we presented a generalized chi-squared test statisticsY2nthat is a convenient tofit the survival and reliability data analysis in presence of three cases: complete, censoredand censored with covariates. We described in detail the theory and the mechanism to usedofY2ntest statistic in the survival and reliability data analysis. Next, we considered theflexible parametric models, evaluating the statistical significance of them by usingY2nandlog-likelihood test statistics. These parametric models include the accelerated failure time(AFT) and a proportional hazards (PH) models based on the Hypertabastic distribution.These two models are proposed to investigate the distribution of the survival and reliabilitydata in comparison with some other parametric models. The simulation studies were de-signed, to demonstrate the asymptotically normally distributed of the maximum likelihood estimators of Hypertabastic’s parameter, to validate of the asymptotically property of Y2n test statistic for Hypertabastic distribution when the right censoring probability equal 0% and 20%.n the last chapter, we applied those two parametric models above to three scenes ofthe real-life data. The first one was done the data set given by Freireich et al. on thecomparison of two treatment groups with additional information about log white blood cellcount, to test the ability of a therapy to prolong the remission times of the acute leukemiapatients. It showed that Hypertabastic AFT model is an accurate model for this dataset.The second one was done on the brain tumour study with malignant glioma patients, givenby Sauerbrei & Schumacher. It showed that the best model is Hypertabastic PH onadding five significance covariates. The third application was done on the data set given by Semenova & Bitukov on the survival times of the multiple myeloma patients. We did not propose an exactly model for this dataset. Because of that was an existing oneintersection of survival times. We, therefore, suggest fitting other dynamic model as SimpleCross-Effect model for this dataset
26
GHASEMI, ABOLFAZL. "Application of Survival Analysis in Forecasting Medical Students at Risk." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1535107693904394.
Повний текст джерела
27
High, Wayne. "A formal protocol test procedure for the Survivable Adaptable Fiber Optic Embedded Network (SAFENET)." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from the National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA267410.
Повний текст джерела
28
Hernández, Velasco Silvia Clara. "Genetics of litter size and prenatal survival in pigs." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6467.
Повний текст джерелаАнотація:
Female reproductive performance is a critical component of sustainable pig production systems. There is abundant evidence of genetic variation in these traits among pig breeds. The aims of this study were to identify quantitative trait loci (QTL) affecting reproductive traits and to identify and characterise positional candidate gene(s) underlying the QTL. A Large White - Meishan F2 population was scanned for QTL with effects on reproductive traits. This analysis revealed 13 putative QTLs on seven different chromosomes with effects on five different traits: ovulation rate (OR), teat number (TN), prenatal survival (PS), total born alive (TBA) and litter size (LS). QTL for PS and LS on chromosome 8 were fine mapped and Secreted Phosphoprotein 1 (SPP1) confirmed as a candidate gene. A genome-wide association study was performed on a diverse population of different breeds and crosses lines, for reproductive traits including LS, TBA, number of stillborn piglets, and number of mummified piglets. Fourteen SNPs were found significantly associated with reproductive traits. The functional study of SPP1 examined the hypothesis that differences in foetal growth may be associated with the effectiveness of conceptus attachment, as measured by SPP1 expression. Patterns of SPP1 mRNA and protein expression in placental and uterine tissues supplying the smallest and a normal-sized foetus from the same uterus were examined in Large White-Landrace (LW-LR), Large White (LW) and Meishan (MS) females 40 and 45 of pregnancy. The smallest LW-LR foetuses tended to have a higher level of SPP1 mRNA in endometrium tissue compared to the normal-sized foetuses. However, placenta expression was higher in the normal-sized foetuses compared to the smallest ones. SPP1 protein levels in normal sized foetuses were significantly higher than in the smallest litter mates for all the tissues. Significantly higher levels of SPP1 mRNA and protein were found in MS compared to LW. In both breeds, significant differences between sizes were found in some tissues, with similar expression patterns in respect to size, for both mRNA and protein in endometrial tissues when compared to contemporary LW. In placenta, the direction of the expression differed between breeds, with a higher expression of mRNA and protein in the normal-sized MS foetuses and in the smallest sized LW foetuses. The comparison of SPP1 expression between different foetal sizes and different breeds revealed associations between breed, foetal size, and SPP1 protein, factors implicated in PS and LS. These results together with the genetic evidence indicate that the potential role of SPP1 in placental and foetal development merits further investigation.
29
Adhikari, Ramesh. "Two Essays in Finance: “Selection Biases and Long-run Abnormal Returns” And “The Impact of Financialization on the Benefits of Incorporating Commodity Futures in Actively Managed Portfolios”." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2050.
Повний текст джерелаАнотація:
This dissertation consists of two essays. First essay investigates the implications of researcher data requirement on the risk-adjusted returns of firms. Using the monthly CRSP data from 1925 to 2013, we present evidence that firms which survive longer have higher average returns and lower standard deviation of annualized returns than the firms which do not. I further demonstrate that there is a positive relation between firms’ survival and average performance. In order to account for the positive correlation between survival and average performance, I model the relation of survival and pricing errors using a Farlie-Gumbel-Morgenstern joint distribution function and fit resulting the moment conditions to the data. Our results show that even a low correlation between firm survival time and pricing errors can lead to a much higher correlation between the survival time and average pricing errors. Failure to adjust for this data selection biases can result in over/under estimates of abnormal returns by 5.73 % in studies that require at least five years of returns data.
Second essay examines diversification benefits of commodity futures portfolios in the light of the rapid increase in investor participation in commodity futures market since 2000. Many actively managed portfolios outperform traditional buy and hold portfolios for the sample period from January, 1986 to October, 2013. The evidence documented through traditional intersection test and stochastic discount factor based spanning test indicates that financializaiton has reduced segmentation of commodity market with equity and bond market and has increased the riskiness of investing in commodity futures markets. However, diversifying property of commodity portfolios have not disappeared despite the increased correlation between commodity portfolios returns and equity index returns.
30
Denson, Kathleen. "Factors Affecting Discrete-Time Survival Analysis Parameter Estimation and Model Fit Statistics." Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc278405/.
Повний текст джерелаАнотація:
Discrete-time survival analysis as an educational research technique has focused on analysing and interpretating parameter estimates. The purpose of this study was to examine the effects of certain data characteristics on the hazard estimates and goodness of fit statistics. Fifty-four simulated data sets were crossed with four conditions in a 2 (time period) by 3 (distribution of Y = 1) by 3 (distribution of Y = 0) by 3 (sample size) design.
31
Masiulaitytė, Inga. "Regression and degradation models in reliability theory and survival analysis." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100527_134956-15325.
Повний текст джерелаАнотація:
In doctoral thesis redundant systems and degradation models are considered. To ensure high reliability of important elements of the system, the stand-by units can be used. These units are commuted and operate instead of the main failed unit. The stand-by units can function in the different conditions: “hot”, “cold” or “warm” reserving. In the thesis systems with “warm” stand-by units are analyzed. Hypotheses of smooth commuting are formulated and goodness-of-fit tests for these hypotheses are constructed. Nonparametric and parametric point and interval estimation procedures are given. Modeling and statistical estimation of reliability of systems from failure time and degradation data are considered.Daktaro disertacijos tyrimo objektai yra rezervuotos sistemos ir degradaciniai modeliai. Norint užtikrinti svarbių sistemos elementų aukštą patikimumą, naudojami jų rezerviniai elementai, kurie gali būti įjungiami sugedus šiems pagrindiniams elementams. Rezerviniai elementai gali funkcionuoti skirtinguose režimuose: „karštame“, „šaltame“ arba „šiltame“. Disertacijoje yra nagrinėjamos sistemos su „šiltai“ rezervuotais elementais. Darbe suformuluojama rezervinio elemento „sklandaus įjungimo“ hipotezė ir konstruojami statistiniai kriterijai šiai hipotezei tikrinti. Nagrinėjami neparametrinio ir parametrinio taškinio bei intervalinio vertinimo uždaviniai. Disertacijoje nagrinėjami pakankamai bendri degradacijos modeliai, kurie aprašo elementų gedimų intensyvumą kaip funkciją kiek naudojamų apkrovų, tiek ir degradacijos lygio, kuri savo ruožtu modeliuojama naudojant stochastinius procesus.
32
Nakagawa, Janete Tamami Tomiyoshi [UNIFESP]. "Avaliação do Programa Nacional de Controle do Câncer do Colo do Útero no Estado de Mato Grosso: impacto sobre o perfil da doença." Universidade Federal de São Paulo (UNIFESP), 2010. http://repositorio.unifesp.br/handle/11600/9095.
Повний текст джерелаАнотація:
Made available in DSpace on 2015-07-22T20:49:36Z (GMT). No. of bitstreams: 0
Previous issue date: 2010-10-28Em 2002, o Estado de Mato Grosso aderiu à segunda fase de intensificação Programa Nacional de Controle do Câncer do Colo do Útero (PNCCU) como medida de enfrentamento das altas taxas da doença e de morte por neoplasia cervical. Com o objetivo de analisar os principais resultados do PNCCU, foi feito um estudo em duas partes. A primeira parte teve como objetivo levantar o perfil da doença e a cobertura do exame rastreamento pelo PNCCU no Estado. Os objetivos da segunda parte foram: analisar o seguimento clínico da população rastreada, analisar as diferentes características evolutivas da doença associadas aos fatores sócio-demográficos e clínicos, bem como analisar o risco de óbito e a taxa de sobrevida estratificada pelas variáveis sócio-demográficas e clínicas das mulheres que apresentaram carcinoma invasivo. Na primeira parte, foi utilizado estudo do tipo transversal e na segunda parte, foi realizado um estudo de coorte. O período do estudo compreendeu de 2002 a 2007 e abrangeu todos os municípios do Estado de Mato Grosso. A população estudada na primeira fase do estudo correspondeu todas as mulheres que fizeram o exame de rastreamento no ano de 2002. Na segunda parte do estudo, a população correspondeu a uma amostra aleatória representativa das mulheres que apresentaram alterações citológicas na primeira fase do estudo, totalizando 323 mulheres. A fonte de dados utilizada foi o sistema de informação oficial de saúde, dentre eles o SISCOLO, SIM, APAC, além de dados oficiais da Secretaria Estadual de Saúde/MT (SES/MT), dados disponíveis no site do INCA e do DATASUS e prontuários clínicos. Para análise estatística dos dados foram utilizadas técnicas descritivas e inferenciais. Na parte descritiva foram utilizados tabelas, gráficos e medidas de posição e de dispersão. Para avaliar a o risco de adoecer por carcinoma cervical invasor foi utilizado regressão logística univariada e multivariada. Para analisar a taxa de sobrevida global foi utilizado o estimador de Kaplan-Meier e para analisar os fatores prognósticos, foi utilizado o modelo de riscos proporcionais de Cox. Dentre os principais resultados, destaca-se que no período estudado, Mato Grosso apresentou taxas de incidência elevadas, acima da média nacional. Os dados do seguimento clínico mostraram os diferentes desfechos, dentre eles, destaca-se que: entre as 323 mulheres, 18 (6,2%) foram a óbito tendo o câncer do colo do útero como causa básica da morte. Foi analisado o risco de a doença evoluir para o carcinoma invasor, segundo as variáveis sócio-demográficas e clínicas, sendo que as variáveis: faixa etária, estado civil, tabagismo, menarca e município foram as que apresentaram forte associação com a doença na fase invasora. Já na análise de sobrevivência, a taxa de sobrevida global em 60 meses, estimada pelo método de Kaplan-Meier, foi de 66,7%. No modelo final de risco proporcional de Cox, as variáveis com maior risco de óbito foi o estágio avançado da doença e a raça/cor. Estes dados levam a concluir que a doença no Estado de Mato Grosso tem uma determinação social muito grande, considerando a dificuldade de acesso aos serviços de saúde da população desfavorecida pelas condições raciais, sócio-econômicas, e chegam aos serviços com a doença em fase adiantada, quando a chance de sobrevivência é muito pequena. Conclui-se que para o efetivo combate a doença são necessárias políticas governamentais, como o PNCCU, que garantam a universalidade da assistência, principalmente da população desfavorecida socialmente.
In 2002, the State joined the second phase of intensification of the National Program for the Control of Cervical Cancer (PNCCU) as a measure to deal with the high rates of the disease and of death by cervical neoplasia. With the aim of analyzing the main PNCCU results, a two-stage study was carried out. The first phase aimed at presenting the disease profile and the coverage of the screening exam by the PNCCU in the State. The aims of the second phase were to analyze the clinical follow-up of the population that was screened, analyze the different evolutionary characteristics of the disease associated to socio-demographic and clinic factors, as well as analyze the factors associated to death risk and the stratified survival rate by the socio-demographic and clinical variables of women that presented invasive carcinoma. In the first part, the cross-sectional study was used and a cohort study was used in the second phase. The period of study was from 2002 to 2007 and comprised all the municipalities of the State of Mato Grosso. The population studied in the first phase of the study was all the women who had undergone the screening test in 2002. The population used in the second phase of the study was a representative random sample of those that presented cytological alterations in the first phase of the study, a total of 323 women. The source of data used was the official health information system, among them the SISCOLO, SIM, APAC, and also the official data of the State Health Department/MT (SES/MT), data available in the INCA and DATASUS sites and medical records. For the statistical analysis of the data, descriptive and inferential techniques were used. In the descriptive part, tables, graphics and position and dispersion measures were used. In order to evaluate the risk of being sick due to invasive cervical carcinoma, the univariate and multivariate logistic regression analysis was used. The Kaplan-Meier estimator was used to analyze the survival rate and to analyze the prognostic factors, the Cox proportional hazards model was used. Among the main results it is highlighted that in 2002, Mato Grosso presented high incidence rates, above the national average. The data of the clinical follow up showed the different clinical outcomes, among the 323 women, 18 (6,2%) died having as the basic cause of death the cervical cancer. The risk of the disease developing into the invasive carcinoma was analyzed according to the socio-demographic and clinical variables, and the variables: age group, marital status, smoking history, menopause and municipality were those that presented a strong association with the disease in the invasive phase. However, in the survival analysis, the global survival rate in 60 months, estimated by the Kaplan-Meier method, was of 66,7%. In the final Cox proportional hazards model, the variables with higher death risk was the advanced stage of the disease and the race/color. These data lead to a conclusion that the disease in the State of Mato Grosso has a very large social determination, considering the difficulties in the access to the health services by the population affected by racial, socio-economic conditions that arrive in the health services with the disease in an advanced stage, when the survival probability is very small. The conclusion is that for the effective fight against the disease governmental policies such as the PNCCU are necessary, and that the universality of the assistance be guaranteed, mainly to the socially disadvantaged population.
TEDE
BV UNIFESP: Teses e dissertações
33
Austin, William H. "The United States Department of Homeland Security concept of regionalization - Will it survive the test?" Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Sep%5FAustin.pdf.
Повний текст джерелаАнотація:
Thesis (M.S. in Security Studies (Homeland Security and Defense))--Naval Postgraduate School, September 2006.Thesis Advisor(s): Robert Bach. "September 2006." Includes bibliographical references (p. 75-80). Also available in print.
34
Villalba, Wander de Oliveira. "Avaliação do comprometimento pulmonar em pacientes com esclerodermia por meio do teste da caminhada de seis minutos." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/309671.
Повний текст джерелаАнотація:
Orientador: Ilma Aparecida PaschoalTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-08T16:31:05Z (GMT). No. of bitstreams: 1 Villalba_WanderdeOliveira_D.pdf: 1859144 bytes, checksum: 532cfe4e767abd01ec5a17cc59abfa37 (MD5) Previous issue date: 2006
Resumo: INTRODUÇÃO - O envolvimento pulmonar é a principal causa de morte relacionada a Esclerose Sistêmica ( ES ). Um teste simples para avaliar a capacidade de exercício é o teste da caminhada de 6 minutos (TC6), e a distância percorrida é usada como desfecho primário em experimentos clínicos. A variação da saturação da hemoglobina (? Sat) durante o TC6 é preditiva de mortalidade nos pacientes com Hipertensão Arterial Pulmonar (HAP). O objetivo deste trabalho foi avaliar a distância percorrida e a queda na saturação (? Sat), no TC6 em pacientes com ES e estabelecer associações entre os resultados do TC6 com outras variáveis clínicas. MÉTODOS - Foram avaliados 110 pacientes com ES. A variação da saturação foi determinada pela diferença entre a saturação de repouso e a saturação ao final dos seis minutos. Foram consideradas como dessaturação variações iguais ou maiores que 4 pontos percentuais. Os dados clínicos e demográficos foram coletados. Todos os pacientes foram submetidos a radiograma de tórax, tomografia computadorizada de alta resolução, teste de função pulmonar, ecocardiograma e pesquisa de marcadores imunológicos no sangue (Scl70 e FAN). RESULTADOS - As variáveis que se associaram com uma distância da caminhada < 400m (p < 0,05) foram a idade, índice de dispnéia, fibrose no radiograma, pressão arterial pulmonar sistólica > 30 mm Hg e a dessaturação; as variáveis associadas com o ? Sat (p < 0,05) foram a idade, anti ScL 70 positivo, índice de dispnéia, fibrose no radiograma de tórax, CVF < 80%, Pressão sistólica da artéria pulmonar > 30 mm Hg e o escore de opacidade reticular e vidro fosco na tomografia computadorizada. Na análise de regressão logística multivariada, três variáveis foram significativas quando testadas com a distância percorrida: idade, raça e dispnéia; e quatro variáveis foram significativas quando testadas com ? Sat: idade, índice de dispnéia, anti Scl 70 positivo e CVF < 80%. CONCLUSÃO - A dessaturação durante o TC6 fornece informação adicional a respeito da doença pulmonar em pacientes com ES
Abstract: Six minute walk test evaluation of pulmonary involvement in scleroderma patients Pulmonary involvement is the leading cause of systemic sclerosis (SSc) related deaths. A simple test to evaluate exercise capacity is the 6-minute walk test (6MWT), and the walk distance is increasingly used as a primary outcome in clinical trials. Hemoglobin desaturation during a 6MWT is predictive of mortality in patients with primary pulmonary hipertension. Objectives: To evaluate the walk distance and oxygen desaturation (?sat) during the 6MWT in patients with SSc and to establish correlations between the 6MWT results and other clinical variables. Methods: This study analysed 110 SSc patients who underwent 6MWT. ?sat was defined as a decrease of 4 or more points in saturation between the resting point and the end of the test. Clinical and demographic data was collected. All the patients underwent radiological evaluations (X-rays and HRCT), had pulmonary function tests and echocardiograms performed, and the presence of autoantibodies determined. Results: The variables associated with a walk distance < 400 m (p<0.05) were age, dyspnea index, fibrosis on X-ray, PASP =30 mm Hg, desaturation; the variables associated with ? sat (p<0.05) were age, positive anti-Scl 70, dyspnea index, fibrosis on X-ray, FVC < 80%, PASP= 30 mm Hg, ground-glass or reticular opacities on HRCT. In the multivariate logistic regression analysis, 3 variables were significant when tested with walk distance: age, race and dyspnea index; and 4 variables were significant when tested with ? sat: age, dyspnea index, positive anti-Scl-70 and FVC< 80%. (91) Conclusions: Desaturation during a 6MWT provides additional information regarding severity of disease in scleroderma patients with pulmonary manifestations
Doutorado
Clinica Medica
Doutor em Clínica Médica
35
Allen, Brenda. "Emperors of the text: Change and cultural survival in the poetry of Philip Larkin and Carol Ann Duffy." Thesis, University of Canterbury. English, 1999. http://hdl.handle.net/10092/4566.
Повний текст джерелаАнотація:
Philip Larkin and Carol Ann Duffy have been, and are, regarded as a step ahead, as the voices that aid other citizens in their struggle to delineate the nature of their concerns about their society and the changes that must be coped with, internalised and incorporated into daily life. Because they are living in times of change, Larkin and Duffy are forced to find new ways to preserve their cultural identity that are not predicated on traditions that are dying or being superseded. The most startling of these changes, however, also affects Britain at the national and international level and in this thesis I examine the writing (including archival material) and life of these poets to argue that their efforts to deal with change may be seen as mirroring the stance of their nation, since in a nation with an elected government there must be, at some level, approval for and participation in, the modus operandi of that government. That these practices are imperialistic can come as no surprise, but ideas and practices of imperialism have changed. Thus it is that the older of the poets, Philip Larkin, harks back to the time of British Imperial glory, and the younger, Carol Ann Duffy, maintains a watching and speaking brief based on humanistic values of egalitarianism.
Larkin, although he purports to be liberal, especially in matters he regards as the merely conventional, fights against the very structures that could be helpful to him and prioritises the sustaining of a past that has no future except as memory and text. His refusal to conform to the social and canonical demands of his younger days, however, ensures that he experiences ambivalence toward most of the structures he criticises as well as toward those he embraces. Nevertheless, his directionless rebellion paves the way for Carol Ann Duffy to move freely between the canonical and the vernacular, in terms of diction and subject matter. To this, Duffy has added her own determination to interrogate meaning, and to represent a culture that is changing by de constructing and reconstructing canonical form in a way that Larkin did not.
The first two chapters of this thesis are about the importance of data and archive, especially the written word, to ideas of the British Empire, and Larkin's over-reliance on archive in his own life. The dysfunctional subjects of Duffy's poems, who display similar reliance on data and archive, are then discussed and related to her own, contrasting awareness of the difference between data and knowledge. The third chapter, in two parts, demonstrates that the imperialist practices of each poet are carried over into the world of personal relationships. Because of his more rigid attitudes, Larkin does not achieve transcendence in this sphere, but Duffy demonstrates that moments of rapture are possible. The last three chapters deal with the most prominent features of imperialism: religion, territory and war. The chapter on war, in particular, is based on archival material that Larkin wrote during or about war, that he saw fit to keep private until after his death; and the chapter also utilises Duffy's lesser-known early works. The conclusions of these chapters confirm those of the previous chapters.
36
Rois, Rumana Verfasser], and Jürgen [Akademischer Betreuer] [Franke. "Nonparametric Tests for Change Points in Hazard Functions under Random Censorship in Survival Analysis / Rumana Rois ; Betreuer: Jürgen Franke." Kaiserslautern : Technische Universität Kaiserslautern, 2017. http://d-nb.info/1140760904/34.
Повний текст джерела
37
Danieli, Coraline. "Contributions méthodologiques à l’estimation de la survie nette : comparaison des estimateurs et tests des hypothèses du modèle du taux en excès." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10294/document.
Повний текст джерелаАнотація:
La survie nette est un indicateur très utilisé en épidémiologie des cancers. Il s'agit de la survie que l'on observerait si la seule cause de mortalité était le cancer ; il est le seul indicateur épidémiologique utilisable à des fins de comparaisons de survie (entre périodes/pays) car il s'affranchit des éventuelles différences de mortalité dues aux autres causes que le cancer. Le premier objectif de notre travail était d'analyser les performances des différentes méthodes d'estimation de la survie nette sur données simulées ainsi que sur données réelles afin que les méthodes non biaisées soient reconnues scientifiquement et soient les seules à être utilisées par la suite. Nous avons ainsi démontré que deux approches étaient capables d'estimer sans biais la survie nette : l'approche non paramétrique de Pohar-Perme et l'approche reposant sur une modélisation multivariée du taux de mortalité en excès dû au cancer. Cette dernière approche impose une stratégie de construction difficile à mettre en place. Le deuxième objectif était de développer une boîte à outils composée de différents tests permettant de vérifier les différentes hypothèses faites lors de la construction d'un modèle de régression du taux de mortalité en excès. Ces hypothèses concernent habituellement la proportionnalité ou non de l'effet des covariables, leur forme fonctionnelle, ainsi que la fonction de lien utilisée. Le troisième objectif était une application épidémiologique qui visait à étudier l'impact des facteurs pronostiques, tel que le stade au diagnostic, sur la survie nette conditionnelle, en d'autres termes sur la dynamique du taux de mortalité en excès, après la survenue d'un cancer du côlonNet survival is one of the most important indicators in cancer epidemiology. It is defined as the survival that would be observed if cancer were the only cause of death. This is the only one indicator allowing comparisons of cancer impact between countries or time periods because it is not influenced by death because of other causes. The first objective of this work was to compare the performance of several estimators of the net survival in a simulation study and then on real data in order to promote unbiased methods. Those methods are the non-parametric Pohar-Perme method and the parametric multivariable excess rate model. The latest one needs a model building strategy. The use of diagnostic procedures for model checking is an essential part of the modeling process. The second objective was to develop a tool box composed of diagnostic tools allowing to check hypothesis usually considered when constructing an excess mortality rate model, that is, the proportionality or not of the effect of covariates, their functional form and the link function. The third objective deals with the study of the impact of prognostic variables, such as stage at diagnosis, on conditional net survival, that is, on the dynamic of the excess hazard mortality after the diagnosis of colon cancer
38
Saaidia, Noureddine. "Sur les familles des lois de fonction de hasard unimodale : applications en fiabilité et analyse de survie." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14794/document.
Повний текст джерелаАнотація:
En fiabilité et en analyse de survie, les distributions qui ont une fonction de hasard unimodale ne sont pas nombreuses, qu'on peut citer: Gaussienne inverse ,log-normale, log-logistique, de Birnbaum-Saunders, de Weibull exponentielle et de Weibullgénéralisée. Dans cette thèse, nous développons les tests modifiés du Chi-deux pour ces distributions tout en comparant la distribution Gaussienne inverse avec les autres. Ensuite nousconstruisons le modèle AFT basé sur la distribution Gaussienne inverse et les systèmes redondants basés sur les distributions de fonction de hasard unimodaleIn reliability and survival analysis, distributions that have a unimodalor $\cap-$shape hazard rate function are not too many, they include: the inverse Gaussian,log-normal, log-logistic, Birnbaum-Saunders, exponential Weibull and power generalized Weibulldistributions. In this thesis, we develop the modified Chi-squared tests for these distributions,and we give a comparative study between the inverse Gaussian distribution and the otherdistributions, then we realize simulations. We also construct the AFT model based on the inverseGaussian distribution and redundant systems based on distributions having a unimodal hazard ratefunction
39
Brito, Leonardo Barbosa Barreto de. "Teste de sentar-levantar: relação com a mortalidade por todas as causas e com a flexibilidade." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9352.
Повний текст джерелаАнотація:
Sabe-se que um estilo de vida sedentário e uma condição aeróbica baixa são associados com uma maior chance de desenvolvimento de doenças cardiovasculares e um maior risco de mortalidade por todas as causas. Contudo, é possível que outros indicadores de aptidão física possam ter significado clínico prognóstico. Originalmente proposto em 1999, o teste de sentar-levantar (TSL) é, simples de executar e possui comprovada reprodutibilidade inter e intra-avaliador. O avaliado inicia o teste com o escore máximo de 5 pontos para cada uma das ações de sentar e levantar, sendo subtraído do mesmo, um ponto para cada apoio extra utilizado (mão, braço e joelho) e meio ponto para cada desequilíbrio corporal perceptível. A pontuação do TSL escore, variando de 0 a 10, é realizada pela soma das ações de sentar e levantar. Considerando o potencial papel da flexibilidade para uma execução mais eficiente de gestos motores, não é surpreendente que o desempenho sobre TSL possa ser influenciado por essa valência. O objetivo desta dissertação foi analisar a relação entre o resultado do TSL e a mortalidade por todas as causas e a flexibilidade. No primeiro estudo, 2002 indivíduos entre 51 e 80 anos (68% homens), realizaram o TSL e os resultados foram estratificados em quatro faixas: 0/3; 3,5/5,5, 6/7,5 and 8/10. Baixos resultados no TSL escore foram associados com um maior risco de mortalidade (p<0,001). Uma tendência contínua de maior sobrevivência se refletiu no ajuste multivariado idade, sexo, índice de massa corporal em um razão de risco de 5,44 [95%IC=3,19,5], 3,44 [95%IC=2,05,9] e 1,84 [95%IC=1,13,0] (p<0,001) dos menores para as maiores faixas de resultados do TSL. Cada aumento de um ponto no escore do TSL significou uma melhora de 21% na sobrevivência. Já o segundo estudo, contou com 3927 indivíduos (67,4% homens) que realizaram o TSL e o Flexiteste. O Flexiteste avalia a amplitude máxima passiva de 20 movimentos corporais. Para cada um dos movimentos, existem cinco escores possíveis, 0 a 4 em uma ordem de mobilidade crescente. A soma dos resultados dos 20 movimentos fornece uma pontuação de flexibilidade global denominada de Flexíndice (FLX). Os resultados do FLX foram estratificados em quartis (626, 2735, 3644 and 4577). Os valores do TSL em cada quartil diferiram entre si (p<0,001). Além disso, o escore do TSL e o FLX foram diretamente associados (r=0,296; p<0,001). Os indivíduos com um TSL escore zero são menos flexíveis para todos os 20 movimentos do Flexiteste do que aqueles com escore 10. Portanto, os dados da presente dissertação, indicam que: o resultado do TSL se mostrou um importante preditor de mortalidade por todas as causas para indivíduos entre 51-80 anos de idade e que indivíduos mais flexíveis tendem a ter maiores escores no TSL.It is known that a sedentary lifestyle and low aerobic fitness are associated with a greater chance of developing cardiovascular disease and increased risk of mortality from all causes. However, it is possible that other indicators of physical fitness may have clinical significance prognosis. Originally proposed in 1999, the sitting-rising test (SRT) is simple to perform and has proven its reliability. The individual begins the test with the maximum score of 5 points for each of the actions of sitting and rising, and being deducted a point for each extra support used (hand, arm and knee) and half a point for each body imbalance noticeable. The SRT score, ranging from 0 to 10, is performed by the sum of the actions of sitting and rising. Considering the potential role of flexibility for a more efficient execution of motor gestures, it is not surprising that the performance of SRT can be influenced by this valence. The aim of this thesis was to analyze association of SRT score and mortality for all-causes and lexibility. In the first study, 2002 individuals between 51 and 80 years (68% men) underwent the SRT and were stratified into four groups: 0/3, 3.5/5.5, 6/7.5 and 8/10. SRT results in low scores were associated with an increased risk of mortality (p <0.001). A continuous trend for longer survival was reflected by multivariate adjusted age, sex, body mass index - hazard ratios of 5.44 [95%CI=3.19.5], 3.44 [95%CI=2.05.9] and 1.84 [95%CI=1.13.0] (p<.001) from lower to higher SRT scores. Each unit increase in SRT score conferred a 21% improvement in survival. The second study included 3927 individuals (67.4% men) who performed the SRT and Flexitest. Flexitest evaluates the maximum passive range of motion of 20 body joint movements. For each one of the movements, there are five possible scores, 0 to 4 in a crescent mobility order. Adding the results of the 20 movements provides an overall flexibility score called Flexindex (FLX). The results of SRT scores were stratified into quartiles (6-26, 27-35, 36-44 and 45-77) and its FLX results differed between (p<0.001). SRT and FLX scores were moderately and positively associated (r = 0.296; p < 0.001). Besides, subjects with a zero SRT score are less flexible for all 20 Flexitest movements than those scoring 10.Therefore, the data of this thesis, showed that the SRT proved an important predictor of mortality from all causes for individuals between 51-80 years of age and that more flexible individuals tend to have higher scores on the SRT.
40
Casalle, Nicole. "Susceptibilidade de carcinoma espinocelular oral ao óleo essencial de Melaleuca Alternifolia e suas principais porções solúveis /." Araraquara, 2016. http://hdl.handle.net/11449/144695.
Повний текст джерелаАнотація:
Orientador: Cleverton Roberto de AndradeResumo: O óleo essencial de Melaleuca alternifolia (tea tree oil - TTO) é composto por aproximadamente 100 componentes, sendo que os de maior concentração são o terpinen-4-ol e gama-terpineno. Os estudos da sua capacidade citotóxica têm demonstrado efeito sobre linhagens neoplásicas malignas. O objetivo do trabalho foi avaliar a capacidade citotóxica e mutagênica do TTO e seus componentes, terpinen-4-ol e gama terpineno em culturas celulares. Duas linhagens de carcinomas espinocelulares orais e uma linhagem de ceratinócitos foram analisadas por: (1) Análise colorimétrica de Metiltetrazolium (MTT); (2) Teste do Micronúcleo. Os resultados foram expressos na forma de ensaios de susceptibilidade e grau de mutagenicidade. Posteriormente foram analisados por one-way Anova com pós-teste de Tukey. Os valores de IC50 obtidos nas análises de MTT das células expostas ao TTO foram de 0,2% para a HaCaT, 0,14% para a HSC-3 e 0,17% para a SCC-25. Para a exposição ao terpinen-4ol, os valores de IC50, foram 0,5%, 0,3% e 0,45% para as linhagens HaCaT, HSC-3 e SCC-25, respectivamente. O gama-terpineno, não demonstrou atividade citotóxica expressiva, não sendo possível calcular o IC50. O TTO não demonstrou mutagenicidade nas linhagens HaCaT e HSC-3. O terpinen-4-ol, não foi capaz de produzir mutagenicidade em nenhuma das linhagens em estudo. Conclui-se que tanto o TTO quanto o terpinen-4-ol apresentam capacidade citotóxica sobre as linhagens HaCaT, HSC-3 e SCC-25. O TTO não foi mutagênico nas linhagens... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The essential oil of Melaleuca alternifolia (tea tree oil - TTO) consists of about 100 components, and the highest concentration are terpinen-4-ol and gammaterpinene. Studies of their cytotoxic capacity have shown effect on malignant neoplastic lineages. The aim of this study was to evaluate the cytotoxic and mutagenic capacity of TTO and main soluble components, terpinen-4-ol and gama-terpinene in cell cultures. Two lineages of oral squamous cell carcinoma and a keratinocyte cell were analyzed: (1) colorimetric analysis Metiltetrazolium (MTT); (2) Micronucleus assay. The results were expressed as susceptibility tests and degree of mutagenicity. The statistical test used in the analysis was one-way ANOVA (Tukey test). The IC50 values obtained from the MTT analysis of cells exposed to TTO were 0.2% for HaCaT, 0.14% for HSC-3, and 0.17% for SCC-25. For exposure to terpinen-4ol, IC50 values were 0.5%, 0.3% and 0.45% for HaCaT, HSC-3 and SCC-25, respectively. The gamma-terpinene didn't show significant cytotoxic activity, therefore it was impossible to calculate the IC50. The TTO was unable to produce mutagenicity in HSC-3 and HaCaT. The terpinen-4-ol was not mutagenic in any of the lineages tested. In conclusion, both the TTO and terpinen- 4-ol had cytotoxic capacity on HaCaT, HSC-3 and SCC-25. The TTO was unable to produce mutagenicity in HSC-3 and HaCaT. The terpinen-4-ol was not mutagenic in any of the lineages tested.
Mestre
41
Melo, Brian Alvarez Ribeiro de. "Análise Bayesiana de modelos de mistura finita com dados censurados." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-11052017-163847/.
Повний текст джерелаАнотація:
Misturas finitas são modelos paramétricos altamente flexíveis, capazes de descrever diferentes características dos dados em vários contextos, especialmente na análise de dados heterogêneos (Marin, 2005). Geralmente, nos modelos de mistura finita, todas as componentes pertencem à mesma família paramétrica e são diferenciadas apenas pelo vetor de parâmetros associado a essas componentes. Neste trabalho, propomos um novo modelo de mistura finita, capaz de acomodar observações censuradas, no qual as componentes são as densidades das distribuições Gama, Lognormal e Weibull (mistura GLW). Essas densidades são reparametrizadas, sendo reescritas em função da média e da variância, uma vez que estas quantidades são mais difundidas em diversas áreas de estudo. Assim, construímos o modelo GLW e desenvolvemos a análise de tal modelo sob a perspectiva bayesiana de inferência. Essa análise inclui a estimação, através de métodos de simulação, dos parâmetros de interesse em cenários com censura e com fração de cura, a construção de testes de hipóteses para avaliar efeitos de covariáveis e pesos da mistura, o cálculo de medidas para comparação de diferentes modelos e estimação da distribuição preditiva de novas observações. Através de um estudo de simulação, avaliamos a capacidade da mistura GLW em recuperar a distribuição original dos tempos de falha utilizando testes de hipóteses e estimativas do modelo. Os modelos desenvolvidos também foram aplicados no estudo do tempo de seguimento de pacientes com insuficiência cardíaca do Instituto do Coração da Faculdade de Medicina da Universidade de São Paulo. Nesta aplicação, os resultados mostram uma melhor adequação dos modelos de mistura em relação à utilização de apenas uma distribuição na modelagem dos tempos de seguimentos. Por fim, desenvolvemos um pacote para o ajuste dos modelos apresentados no software R.Finite mixtures are highly flexible parametric models capable of describing different data features and are widely considered in many contexts, especially in the analysis of heterogeneous data (Marin, 2005). Generally, in finite mixture models, all the components belong to the same parametric family and are only distinguished by the associated parameter vector. In this thesis, we propose a new finite mixture model, capable of handling censored observations, in which the components are the densities from the Gama, Lognormal and Weibull distributions (the GLW finite mixture). These densities are rewritten in such a way that the mean and the variance are the parameters, since the interpretation of such quantities is widespread in various areas of study. In short, we constructed the GLW model and developed its analysis under the bayesian perspective of inference considering scenarios with censorship and cure rate. This analysis includes the parameter estimation, wich is made through simulation methods, construction of hypothesis testing to evaluate covariate effects and to assess the values of the mixture weights, computatution of model adequability measures, which are used to compare different models and estimation of the predictive distribution for new observations. In a simulation study, we evaluated the feasibility of the GLW mixture to recover the original distribution of failure times using hypothesis testing and some model estimated quantities as criteria for selecting the correct distribution. The models developed were applied in the study of the follow-up time of patients with heart failure from the Heart Institute of the University of Sao Paulo Medical School. In this application, results show a better fit of mixture models, in relation to the use of only one distribution in the modeling of the failure times. Finally, we developed a package for the adjustment of the presented models in software R.
42
Ben, elouefi Rim. "Inférence statistique dans le modèle de mélange à risques proportionnels." Thesis, Rennes, INSA, 2017. http://www.theses.fr/2017ISAR0011/document.
Повний текст джерелаАнотація:
Dans ce travail, nous nous intéressons à l'inférence statistique dans deux modèles semi-paramétrique et non-paramétrique stratifiés de durées de vie censurées. Nous proposons tout d'abord une statistique de test d'ajustement pour le modèle de régression stratifié à risques proportionnels. Nous établissons sa distribution asymptotique sous l'hypothèse nulle d'un ajustement correct du modèle aux données. Nous étudions les propriétés numériques de ce test (niveau, puissance sous différentes alternatives) au moyen de simulations. Nous proposons ensuite une procédure permettant de stratifier le modèle à 1isques proportionnels suivant un seuil inconnu d'une variable de stratification. Cette procédure repose sur l'utilisation du test d'ajustement proposé précédemment. Une étude de simulation exhaustive est conduite pour évaluer les pe1fonnances de cette procédure. Dans une seconde partie de notre travail, nous nous intéressons à l'application du test du logrank stratifié dans un contexte de données manquantes (nous considérons la situation où les strates ne peuvent être observées chez tous les individus de l'échantillon). Nous construisons une version pondérée du logrank stratifié adaptée à ce problème. Nous en établissons la loi limite sous l'hypothèse nulle d'égalité des fonctions de risque dans les différents groupes. Les propriétés de cette nouvelle statistique de test sont évaluée au moyen de simulations. Le test est ensuite appliqué à un jeu de données médicalesIn this work, we are interested in the statistical inference in two semi-parametric and non-parametric stratified models for censored data. We first propose a goodnessof- fit test statistic for the stratified proportional hazards regression model. We establish its asymptotic distribution under the null hypothesis of a correct fit of the model. We investigate the numerical properties of this test (level, power under different alternatives) by means of simulations. Then, we propose a procedure allowing to stratify the proportional hazards model according to an unknown threshold in a stratification variable. This procedure is based on the goodness-of-fit test proposed earlier. An exhaustive simulation study is conducted to evaluate the performance of this procedure. In a second part of our work, we consider the stratified logrank test in a context of missing data (we consider the situation where strata can not be observed on all sample individuals). We construct a weighted version of the stratified logrank, adapted to this problem. We establish its asymptotic distribution under the null hypothesis of equality of the hazards functions in the different groups. The prope1ties of this new test statistic are assessed using simulatious. Finally, the test is applied to a medical dataset
43
Hultman, Bo. "Clinical and Experimental Studies in Peritoneal Metastases from Gastric Cancer." Doctoral thesis, Uppsala universitet, Kolorektalkirurgi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-197776.
Повний текст джерелаАнотація:
Gastric cancer (GC) is one of leading causes of death in the world, and peritoneal metastases (PM) are a major site of recurrence. PM from GC implies a poor prognosis, with median overall survival (mOS) approximately 3 months and no survival at five years. The aims of this thesis were to explore the incidence and evaluate prognostic factors for mOS of PM from GC in a defined population; to investigate the outcome of a new multimodal treatment; to analyse the treatment costs, and to investigate differences in drug sensitivity between individual patient samples and between various tumours. The incidence of loco-regional advanced GC was 3.8 per 100,000 person-years. Synchronous loco-regional GC in combination with synchronous distant metastasis was a negative prognostic factor while chemotherapy and good performance status, and radiotherapy plus chemotherapy were positive prognostic factors . There were no significant differences in mOS for the group of patients included during the period 2000-2004 versus 2005-2009, and this lack of improvement in mOS during the past decade justifies new treatment approaches. In a Phase II study of patients treated with neoadjuvant systemic chemotherapy followed by cytoreductive surgery + hyperthermic intraperitoneal chemotherapy, mOS was 14.3 months and for patients with macroscopically radical surgery mOS was 19.1 months. The mean overall cost of the loco-regional treatment was $145,700 compared to $59,300 with systemic chemotherapy treatment. In an ex vivo chemo-sensitivity test, it was determined that GC samples were equivalent to colorectal cancer in chemo-sensitivity to standard drugs and targeted drugs, whereas ovarian cancer samples were more sensitive. The individual GC samples varied considerably in sensitivity to increasing concentrations of the drugs, arguing for individualized drug selection. The incidence of loco-regional advanced GC was more common than previously reported and there were no improvements in mOS over the past decade. The mOS for patients with neoadjuvant systemic chemotherapy followed by macroscopically radical cytoreductive surgery + hyperthermic intraperitoneal chemotherapy was better than in recent reports on treatment with systemic chemotherapy. Treatment of advanced GC patients is costly irrespective of treatment modality. The GC samples varied considerably between individuals in terms of sensitivity to increasing concentrations of the drugs and were comparable to colorectal cancer in chemo-sensitivity.
44
Bika, Gildas. "Les logiques de survie des réfugiés de guerre : clinique de la reconstruction post-traumatique dans un pays d’asile : contributions des méthodes projectives (Rorschach et TAT)." Thesis, Lyon 2, 2011. http://www.theses.fr/2011LYO20043/document.
Повний текст джерелаАнотація:
A partir d’une clinique constituée de 15 sujets bourreaux et victimes, cette étude porte sur « Les logiques de survie des réfugiés de guerre », en se servant du Rorschach et du TAT comme «dispositifs à symboliser» (Roussillon, 2003 ; Roman, 2005 ; Dérivois, 2004). Comment les réfugiés se reconstruisent-ils dans un pays d’asile ? A quel niveau topique les traumatismes vécus se seraient-ils enkystés ? A quelles stratégies de survie recourent-ils ? Quels mécanismes de défense mettent-ils en œuvre ? Comment les traumatismes subis, les éventuels (ré) aménagements s’expriment-ils au Rorschach et au TAT ? Enfin, l’établissement des indices d’une « personnalité traumatique » est-elle possible au Rorschach et au TAT ?Il existerait un lien entre les traumatismes subis, les troubles référés à l’identité dans le pays d’asile et les différentes modalités de reconstruction psychiques. Les logiques de survie se déclinent en victimisation et logiques victimaires ; bourreaux et boucs-émissaires ; triomphalismes et engagements ; honte et culpabilité ; errance ; silence ; recherche et création. La somatisation constitue une autre déclinaison.Les effets du traumatique sont souvent pensés sous le primat de la négativité. L’hypothèse du traumatisme-moteur a été envisagée. Enfin, un appareil psychique des liens inter-institutionnels a été modéliséFrom a clinical subjects consisting of 15 executioners and victims, this study focuses on "survival strategies of refugees from war, "using the Rorschach and the TAT as "devices to symbolize" (Roussillon, 2003; Roman 2005; Dérivois, 2004).How do they rebuild refugees in asylum countries? At what level topical traumas would they encysted? Which coping strategies do they use? What defenses are they implemented? How trauma, the possible (re) development they are expressed on the Rorschach and the TAT? Finally, Compiling a "personality disorder" is it possible the Rorschach and the TAT? There is a link between trauma, disorders referred to identity in the country of asylum and the various methods of psychological reconstruction. The logic of survival and victimization are divided into logical victimizers; executioners and scapegoats; triumphalism and commitments; shame and guilt, wander; silence, research and creation. Somatization is another variation. The effects of trauma are often designed under the primacy of negativity. The hypothesis of trauma-engine was considered. Finally, a psychic apparatus of inter-institutional linkages have been modeled
45
Coaguila, Zavaleta Katherine Elizabeth. "Modelos série de potência com excesso de zeros observáveis e latentes." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8890.
Повний текст джерелаАнотація:
Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-06-23T18:57:54Z
No. of bitstreams: 1
TeseKECZ.pdf: 1800356 bytes, checksum: a555e52c04756515d694387c471b4030 (MD5)Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-06-28T08:32:51Z (GMT) No. of bitstreams: 1 TeseKECZ.pdf: 1800356 bytes, checksum: a555e52c04756515d694387c471b4030 (MD5)
Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-06-28T08:33:00Z (GMT) No. of bitstreams: 1 TeseKECZ.pdf: 1800356 bytes, checksum: a555e52c04756515d694387c471b4030 (MD5)
Made available in DSpace on 2017-06-28T08:41:16Z (GMT). No. of bitstreams: 1 TeseKECZ.pdf: 1800356 bytes, checksum: a555e52c04756515d694387c471b4030 (MD5) Previous issue date: 2016-09-28
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
The present work's main objective is to study the significance of zeros in an observable and latent data. In observable data set that occur excess of zeros, its common to have sobredispersion. In this sense, the models zero-inflated power series (ZISP) were proposed to accommodate these excesses. Specifically for the analysis of observed data, it was made a study of gradient statistic, proposed by Terrell (2002), to test the hypotheses in relation to inflation parameter ZISP models. This test is based on evaluation of the performance of gradient statistic compared with the classical likelihood ratio (Wilks, 1938), score (Rao, 1948) and Wald (Wald, 1943) statistics. In addition, recently, fragility has being modeled by discrete distributions using non-negative integers values that allows zero fragility, which means, individuals who do not present the event of interest (fraction of zero risk). For this type of latent data, we have proposed a new survival model induced by discrete frailty with ZISP distribution. This proposal brings a real description of individuals without risk, because individuals cured due to genetic factors (immune) are modeled by fraction of deterministic zero risk, while the cured by treatment are modeled by fraction of random zero risk. In this context, we also developed the gradient statistic to verify parameter significance of zero risk for data modeled by fraction of deterministic zero risk. To show our proposals, we present the results of simulation studies and applications using real data.
O presente trabalho teve como objetivo principal, estudar a significância de zeros numa análise de dados observáveis e latentes. Nos conjuntos de dados observáveis que ocorrem excessos de zeros, é comum a existência de sobredispersão. Neste sentido os modelos Zero-Inflacionados Série de Potência (ZISP) foram propostos para acomodar o excesso de zeros. Especifcamente para a análise de dados observáveis com excesso de zeros desenvolvemos um estudo da estatística gradiente, proposta por Terrell (2002), para testar as hipóteses em relação ao parâmetro de inflação do modelo ZISP, baseado na avaliação da performance da estatística gradiente em comparação com as estatísticas clássicas da razão de verossimilhan ça (Wilks, 1938), escore (Rao, 1948) e Wald (Wald, 1943). Por outro lado, recentemente a fragilidade é modelada por distribuições discretas sob os inteiros não negativos e permite fragilidade zero, isto é, indivíduos que não apresentam o evento de interesse (fração de risco zero). Para este tipo dados de latentes, propusemos um novo modelo de sobrevivência induzida por fragilidade discreta com distribuição ZISP. Essa proposta traz uma descrição mais real dos indivíduos sem risco, pois inclui indivíduos curados devido aos fatores genéticos (imunes) modelados como a fração de risco zero determinístico, enquanto que, os indivíduos curados por tratamento são modelados pela fração de risco zero aleatório. Neste contexto desenvolvemos também a estatística gradiente para verificar a significância do parâmetro de risco zero para dados modelados pela fração de risco zero determinístico. E para completar o desenvolvimento das propostas, apresentamos os resultados de estudos de simulação e exemplos de aplicação com uso de dados reais.
46
Dantas, Poliana Medeiros Cunha. "Avalia??o cl?nica e radiogr?fica das complica??es t?cnicas em pr?teses sobre implantes." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17823.
Повний текст джерелаАнотація:
Made available in DSpace on 2014-12-17T15:43:52Z (GMT). No. of bitstreams: 1
PolianaMCD_DISSERT.pdf: 1792247 bytes, checksum: 7f68d2f3ec1dcc9a4fd54fc8a9e991be (MD5)
Previous issue date: 2012-12-13The evaluation criteria of the cases treated with dental implants are based on clinical and radiographic tests. In this context it is important to conduct research to determine prognosis of different types of prosthetic rehabilitation and determination of the main problems affecting this type of treatment. Thus, the objective of this study was to assess the prosthetic conditions of individuals rehabilitated with implant-supported prosthesis. In this cross-sectional study 153 patients were treated, accounting for a sample of 509 implants. The failures were observed by clinical and radiographic examination. The results showed that the fracture (0.2%) loss (0.4%) and loosening of the screws (3.3%) were failures are less frequent. The fracture structures as the resin (12.4%), porcelain (5.5%) and metallic (1.5%), loss of resin that covers the screw (23.8%) and loss of retention overdentures on implants (18.6%) had a higher occurrence. The failure of adaptation between the abutment and the implant (6.9%) and especially between the prosthesis and the abutment (25.4%) had a high prevalence and, when related to other parameters showed a significant association, particularly with the cemented prosthesis (OR = 6.79). It can be concluded that to minimize the appearance of failures, protocols must be observed from diagnosis to the settlement and control of prostheses on implants, particularly with respect to technical steps of the making of the prosthesis and care in radiographic evaluating the fit between their components
Os crit?rios de avalia??o dos casos tratados com implantes osseointegrados s?o baseados em testes cl?nicos e exames radiogr?ficos. Nesse contexto, ? importante a realiza??o de pesquisas na determina??o do progn?stico dos diferentes tipos de reabilita??es prot?ticas e na determina??o dos principais problemas que atingem este tipo de tratamento. Desta forma, o objetivo deste trabalho foi avaliar as condi??es prot?ticas de indiv?duos reabilitados com implantes osseointegrados e pr?teses sobre implantes. Neste estudo transversal foram atendidos 153 pacientes, contabilizando uma amostra de 509 implantes. As falhas foram observadas atrav?s do exame cl?nico e radiogr?fico. Os resultados demonstraram que a fratura (0,2%), a perda (0,4%) e o afrouxamento dos parafusos (3,3%) foram as falhas menos frequentes. A fratura das estruturas como a resina (12,4%), porcelana (5,5%) e met?lica (1,5%), a perda da resina que recobre o parafuso de fixa??o (23,8%) e a perda de reten??o nas pr?teses overdentures (18,6%), tiveram uma ocorr?ncia maior. A falha de adapta??o, entre o pilar e o implante (6,9%) e principalmente entre a pr?tese e o pilar (25,4%) teve uma alta preval?ncia e, quando relacionada com outros par?metros, demonstrou uma associa??o significativa, principalmente com a fixa??o do tipo cimentada (OR= 5,39). Pode-se concluir que para minimizar o aparecimento de falhas, protocolos devem ser observados desde o diagn?stico at? o assentamento e controle das pr?teses sobre implantes, principalmente com rela??o aos passos t?cnicos da confec??o da pr?tese e com o cuidado em avaliar radiograficamente a adapta??o entre seus componentes
47
Nenad, Šolajić. "Prognostički značaj gustine tumorskih pupoljaka i citoplazmatskih pseudofragmenata u tumorskom tkivu karcinoma kolona kod bolesnika u stadijumu II." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=101547&source=NDLTD&language=en.
Повний текст джерелаАнотація:
UVOD: Karcinom kolona (KK) je velik javnozdravstveni problem usled visoke incidence i stope mortaliteta. Kod KK je stadijum bolesti najvažniji pojedinačni nezavisni faktor prognoze. U prisustvu nepovoljnih prognostičkih parametara, u koje spadaju visok histološki gradus, ileus, limfo-vaskularna i perineuralna invazija, nakon potencijalno kurativne operacije se kod pacijenata u stadijumu II indikuje primena adjuvantne hemioterapije koja ima pozitivan uticaj na ukupno preživljavanje i na produženje perioda bez bolesti. Međutim, relapsi bolesti nastaju kod nekih bolesnika bez negativnih prognostičkih faktora, što ukazuje na moguće postojanje drugih tkivnih faktora loše prognoze. U novije vreme se sve veća pažnja posvećuje fenomenu tumorskog pupljenja koje predstavlja pojavu tumorskih pupoljaka (TP), odnosno oligocelularnih grupa tumorskih ćelija koje se na invazivnom frontu tumora odvajaju od glavne tumorske mase. Ove tumorske ćelije poprimaju fenotip mezenhimnih ćelija i stiču sposobnost ameboidnog kretanja kroz ekstracelularni matriks, uz pomoć citoplazmatskih podija koje se na dvodimenzionalnim histološkim rezovima vizualizuju kao citoplazmatski pseudofragmenti (CPF). Značaj gustine TP i CPF je još uvek nedovoljno ispitan, ali postoje indicije da se radi o moćnom prediktoru biološkog ponašanja tumora. CILJ: Cilj je bio da se ispita zavisnost dužine perioda bez relapsa, veličine primarnog tumora, gustine peritumorske limfocitne infiltracije i konfiguracije tumorske margine od gustine TP i CPF kod bolesnika sa KK u stadijumu II. METODOLOGIJA: Istraživanjem je obuhvaćeno 114 bolesnika operisanih od KK u stadijumu II na Institutu za onkologiju Vojvodine, bez nepovoljnih prognostičkih faktora i bez indikacija za primenu adjuvantne hemioterapije. Mikroskopskom analizom rutinskih histoloških i imunohistohemijskih preparata utvrđivana je gustina TP i CPF, koja je zatim korelirana sa vremenom pojave relapsa, veličinom primarnog tumora, gustinom peritumorske limfocitne infiltracije i konfiguracijom tumorske margine. REZULTATI: Velika gustina TP i/ili CPF nađena je kod 45 tumora (39,5%). U ovoj grupi se relaps dogodio kod 26 bolesnika (57,8%). U grupi bolesnika sa malom gustinom TP/CPF relaps je registrovan u 4 slučaja (5,8%). Poređenje krivih preživljavanja pokazalo je da je verovatnoća relapsa značajno veća ako se u tumoru nalazi velika gustina TP/CPF (p<0,0001). Tumori sa velikom gustinom TP/CPF su imali najveći prečnik koji je varirao u rasponu od 25 do 100 mm, dok su tumori sa malom gustinom TP/CPF bili najvećeg prečnika od 20 do 110 mm (p=0,6744). Intenzitet peritumorskog limfoidnog odgovora je bio velik kod 13 tumora sa velikom gustinom TP/CPF (28,9%) i kod 17 tumora sa malom gustinom TP/CPF (24,6%), p=0,7747. Konfiguracija tumorske margine je bila infiltrativna u svim tumorima sa velikom gustinom TP/CPF, kao i kod 42 tumora sa malom gustinom TP/CPF (60,9%). ZAKLJUČAK: Velika gustina TP/CPF je nezavisan tkivni indikator loše prognoze kod bolesnika sa KK u stadijumu II, koji je ne korelira ni sa veličinom primarnog tumora ni sa intenzitetom peritumorskog limfoidnog odgovora. Velika gustina TP/CPF nije kompatibilna sa ekspanzivnom konfiguracijom tumorske margine, ali infiltrativna konfiguracija tumorske margine nije prediktor velike gustine TP/CPF.INTRODUCTION: Colonic carcinoma (CC) is a serious public health problem due to its high incidence and mortality rate. Stage is the single most important independent prognosticator in patients with CC. In the presence of indicators of poor prognosis, including high histologic grade, ileus, lympho-vascular invasion and perineural invasion, there is a need for adjuvant chemotherapy after a potentially curative operation in patients with stage II CC, because the therapy improves both overall survival and disease-free survival. However, some patients with no documented poor prognostic factors suffer recurrences, which indicates that there may be some other tissue features that confer poor prognosis. In the recent publications there is an increasing interest in the phenomenon of tumor budding, a term assigned to the presence of small groups of discohesive tumor cells at the invasive front of the tumor – tumor buds (TB's). These cells acquire mesenchymal phenotype and gain the ability to migrate through the extracellular matrix by means of cytoplasmic extrusions which are visible on the two-dimensional immunohistologic sections and are called cytoplasmic pseudofragments (CPF's). Significance of density of TB's and CPF's is still to be evaluated, but the pool of evidence suggests that this is a powerful predictor of biologic behaviour of CC. AIM: The aim of this study was to determine the influence of density of TB's and CPF's on the risk of recurrence in patients with stage II CC. This research also attempted to establish whether there is a correlation between the density of TB's and CPF's and several other morphologic features such as tumor diameter, peritumoral lymphocytic response and the configuration of the tumor margin. METHODS: 114 patients with stage II CC were enrolled in the study. All the patients received surgery at the Institute of Oncology in Sremska Kamenica and no patient had indication for adjuvant chemotherapy. Microscopic analysis of routine histologic and immunohistochemical slides was performed to establish the density of TB's and CPF's, to estimate the intensity of the peritumoral lymphocytic response and to determine the configuration of the tumor margin. RESULTS: High density of TB's and/or CPF's was found in 45 tumors (39.5%). In this group recurrence occured in 26 patients (57.8%). In the group of patients with low density of TB/CPF in the tumor tissue 4 patients relapsed (5.8%). Comparison of survival curves showed that the probability of recurrence was significantly greater if the density of TB/CPF's was high (p<0.0001). Tumors with high density of TB/CPF's ranged from 25 to 100 mm in greatest diameter, while those with low density measured from 20 to 110 mm (p=0.6744). Intensity of peritumoral lymphocytic response was high in 13 tumors with high density of TB/CPF's (28.9%) and in 17 tumors with low density of TB/CPF's (24.6%), p=0.7747. All tumors with high density of TB/CPF's and 42 tumors with low density of TB/CPF's (60.9%) had infiltrative configuration of tumor margin. CONCLUSION: High density of TB/CPF's is an independent indicator of poor prognosis in patients with stage II CC and it correlates neither with tumor diameter nor with intensity of peritumoral lymphocytic response. High density of TB/CPF's is not compatible with the expansive configuration of tumor margin, but the infiltrative configuration of tumor margin is not a predictor of high density of TB/CPF's.
48
Cowan, Nigel Christopher. "The development of CT urography for investigating haematuria." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:284084de-2a71-4e35-8342-41f039b03df1.
Повний текст джерелаАнотація:
This thesis addresses the three principal questions concerning the development of CT urography for investigating haematuria and each question is the subject of a separate chapter. The questions are: What is the reasoning behind using CT urography? What is the optimum diagnostic strategy using CT urography? What are the problems with using CT urography and how may solutions be provided? Haematuria can signify serious disease such as urinary tract stones, renal cell cancer, upper tract urothelial cancer (UTUC) and bladder cancer (BCa). CT urography is defined as contrast enhanced CT examination of kidneys, ureters and bladder. The technique used here includes unenhanced, nephrographic and excretory-phases for optimized diagnosis of stones, renal masses and urothelial cancer respectively. The reasoning behind using excretory-phase CT urography for investigating haematuria is based on results showing its high diagnostic accuracy for UTUC and BCa. Patients with haematuria are classified as low risk or high risk for UTUC and BCa, by a risk score, determined by the presence/absence of risk factors: age > 50 years, visible or nonvisible haematuria, history of smoking and occupational exposure. The optimum diagnostic strategy for patients at high risk for urothelial cancer, uses CT urography as a replacement test for ultrasonography and intravenous urography and as a triage test for flexible and rigid cystoscopy, resulting in earlier diagnosis and potentially improving prognosis. For patients at low risk, ultrasonography, unenhanced and nephrographic-phase CT urography are proposed as initial imaging tests. Problems with using CT urography include false positive results for UTUC, which are eliminated by retrograde ureteropyelography-guided biopsy, an innovative technique, for histopathological confirmation of diagnosis. Recommendations for the NHS and possible future developments are discussed. CT urography, including excretory-phase imaging, is recommended as the initial diagnostic imaging test before cystoscopy for patients with haematuria at high risk for urothelial cancer.
49
JENG, JR-FENG, and 鄭智峯. "A test for survival functions of quality of life adjusted survival time." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/92591323776627818285.
Повний текст джерелаАнотація:
碩士國立臺北大學
統計學系
91
A major purpose in many clinical trials is to compare two competing treatments in a randomized experiment. The conventional way of performing this task is to compare patients’ total survival times, which are defined as either time to death or time to some adverse event, such as disease and relapse. However, in clinical trials such as studying chronic diseases, it does not suffice to consider simple time-to-event endpoints since a new experimental treatment may have the potential of extending overall survival but can be toxic for longer periods of time. Therefore, taking patients’ quality of life into account in the treatment comparisons will be more meaningful. Thus, adapting the method by Zhao and Tsiatis (2001), we present a test for survival functions of quality of life adjusted survival time. This test statistic is the ordinary log-rank test when quality-adjusted lifetime is the same as the survival time. Simulations are conducted to examine the behavior of the test statistic under both null and alternative hypotheses. Finally we apply this test statistic to a breast cancer study for comparing the distribution of quality of life adjusted survival time between breast cancer surgery with radiation and mastectomy.
50
Chih, Hsu Min, and 許敏智. "Empirical Bayes Test in Two-Sample Survival Ananlysis." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/08278280482711095142.
Повний текст джерела