Rift Valley fever (RVF) is a mosquito-borne zoonotic disease caused by a virus of the family Bunyaviridae, genus Phlebovirus. It is responsible for extensive outbreaks of disease in livestock in Africa with significant mortality and economic impact. Virus neutralization is considered the gold standard for confirming Rift Valley fever virus (RVFV) infection but the procedure is time consuming and expensive. Real-time reverse transcription-polymerase chain reaction (rRT-PCR), histopathology, and immunohistochemistry (IHC) are the diagnostic methods most often used in South Africa to confirm or exclude a diagnosis of RVF in necropsied animals. Validated estimates of diagnostic accuracy of these tests, in naturally infected livestock, however, have not been published. The objective of this study was to estimate the diagnostic sensitivity and specificity of rRT-PCR, histopathology, and IHC using Bayesian latent class methods in the absence of a gold standard. A secondary objective was to estimate stratum-specific values based on species, age, degree of specimen autolysis, and the presence/absence of tissue pigments. The Sensitivity (Se) and Specificity (Sp) of qRT-PCR were 97.4% (95% credibility interval (CI): 95.2% - 98.8%) and 71.7% (95% CI: 65% - 77.9%) respectively. The extraordinary analytical sensitivity of PCR makes this test very susceptible to false positive reactions, and thus reduced specificity. This is more likely during large-scale epidemics due to crosscontamination of specimens at necropsy facilities or testing laboratories. The Se and Sp of histopathology were 94.6% (95% CI: 91% - 97.2%) and 92.3% (95% CI: 87.6% - 95.8%) respectively. Single cases of RVF could be confused with acute poisoning with plants, bacterial septicaemias, and viral diseases such as infectious bovine rhinotracheitis and Wesselsbron disease. Most of these conditions, however, can be excluded using histological examination of the liver, special stains, bacterial culture, and toxicological or serological investigations. The Se and Sp of IHC were 97.6% (95% CI: 93.9% - 99.8%) and 99.4% (95% CI: 96.9% - 100%) respectively. Immunohistochemistry is highly specific because characteristic positive immunolabelling of the cytoplasm of hepatocytes can be correlated with the presence of hepatocellular injury typical for RVFV infection. False negative results are sometimes obtained with IHC because of reader error or loss of the antigenic epitopes due to advanced autolysis. Scant positive immunolabelling might be missed or viral proteins might be absent from sections of liver with advanced hepatocellular damage. The stratified analysis suggested differences in test accuracy in foetuses and severely autolysed specimens. The Sp of histopathology in foetuses (83.0%) was 9.3% lower than the value obtained for the sample population (92.3%). Lesions in some foetuses are more subtle and the typical eosinophilic intranuclear inclusions are often difficult to detect. In severely autolysed specimens, the Se of IHC decreased by 16.1% and the Sp of rRT-PCR by 17.4%. There is no plausible biological explanation for this decrease in the Sp of rRTPCR since the RNA of RVFV is resistant to degradation in autolysed tissues. Conversely, the antibody used to detect RVFV using IHC detects epitopes raised against nucleoproteins of the virus and it is possible that viral proteins become too widely dispersed and/or degraded in autolysed tissues to detect by light microscopy. It is possible that the marked decrease in Se of histopathology and IHC in severely autolysed specimens caused an apparent decrease in Sp of rRT-PCR, due to the latent class method. In conclusion, the high estimated Sp (99.4%) of IHC and the low Sp of rRT-PCR (71.3%) suggests that the definitive diagnosis or exclusion of RVF should not rely on a single PCR test and that IHC would be an effective confirmatory test for rRT-PCR positive field cases necropsied during an epidemic. Immunohistochemistry results from severely autolysed specimens, however, should be interpreted with caution and aborted foetuses in areas endemic for RVF should be screened using a variety of tests. The diagnostic Se and Sp of histopathology was much higher than expected confirming the value of routine post mortem examinations and histopathology of liver specimens. The most feasible RVF testing option in areas that do not have suitably equipped PCR laboratories, and where disease is often not detected in livestock until after human cases have been diagnosed, would be routine histopathology screening with IHC confirmation. Key Words: Rift Valley fever; Rift Valley fever virus; Bayesian; latent-class model; real-time reverse transcription-polymerase chain reaction; immunohistochemistry; histopathology; diagnosis; sensitivity; specificity. / Dissertation (MSc)--University of Pretoria, 2014. / gm2014 / Paraclinical Sciences / unrestricted

The thesis "The Potential of Latent Class Analysis: the Czech Television Audience Case Study" deals with latent class analysis and it's potential as a segmentation method. Three different approaches are examined - latent class analysis for joint data from six research waves, simultaneous latent class analysis for each wave separately and latent class analysis for joint data transferred into dichotomous form. The results of all three methods are compared through secondary analysis of data from case study focused on audience's perception of the Czech Television; their strong and weak points are described and the most suitable solution is chosen. Based on these findings, four identified segments of the audience are then interpreted from the point of their characteristic features and sociodemographic parameters. This paper is supported by works of classic authors in the area of latent class analysis; the thesis refers to their findings that also served as basis for composition of the research hypotheses.

Title: Joint Models for Longitudinal and Time-to-Event Data Author: Jana Vorlíčková Department: Department of Probability and Mathematical Statistics Supervisor: doc. RNDr. Arnošt Komárek, Ph.D., Department of Probability and Mathematical Statistics Abstract: The joint model of longitudinal data and time-to-event data creates a framework to analyze longitudinal and survival outcomes simultaneously. A commonly used approach is an interconnection of the linear mixed effects model and the Cox model through a latent variable. Two special examples of this model are presented, namely, a joint model with shared random effects and a joint latent class model. In the thesis we focus on the joint latent class model. This model assumes an existence of latent classes in the population that we are not able to observe. Consequently, it is assumed that the longitudinal part and the survival part of the model are independent within one class. The main intention of this work is to transfer the model to the Bayesian framework and to discuss an estimation procedure of parameters using a Bayesian statistic. It consists of a definition of the model in the Bayesian framework, a discussion of prior distributions and the derivation of the full conditional distributions for all parameters of the model. The model's ability to...

Ce mémoire a été fait sous la tutelle de Jean Proulx. Il a été évalué par un jury composé de Denis Lafortune, Jean Proulx et Catherine Arseneault. Suite à l'évaluation du mémoire, ce dernier a été recommandé à la liste d'honneur du doyen et du recteur, et a été soumis pour le prix du meilleur mémoire de la FESP 2022. / Encore à ce jour, le portrait de l’agresseur sexuel sadique rapporté dans la littérature ne fait pas consensus, et ce notamment dû aux limites des études desquelles il découle (ex. : définition du sadisme sexuel qui ne fait pas consensus, échantillon hétérogène, temporalité fixée à l’âge adulte). Dans l’objectif de combler ces limites, nous avons examiné, à partir d’un échantillon composé de 206 agresseurs sexuels de femmes adultes, incarcérés au Québec (Canada), et sur la base d’une définition du sadisme sexuel validée empiriquement, la Severe Sexual Sadism Scale (SESAS), et d’une centaine de variables s’étalant de l’enfance à la phase post-délictuelle, ce qui distingue les agresseurs sexuels sadiques (n = 69) des non-sadiques (n = 137). Pour ce faire, des analyses bivariées (chi-deux) ont été réalisées. Ces analyses ont révélé que les agresseurs sexuels sadiques et non-sadiques de femmes adultes se distinguent sur plusieurs aspects, notamment de nature développementale (ex. : victimisation avant l’âge de 18 ans), psychologique (ex. : personnalité, psychopathologie), sexologique (ex. : fantaisies sexuelles déviantes) et criminologique (ex. : modus operandi). En outre, nous avons examiné, auprès du même échantillon, si le sadisme sexuel constitue ou non un phénomène hétérogène. À cette fin, des analyses de classes latentes ont été réalisées sur les items de la SESAS, lesquelles nous ont révélé que le sadisme sexuel ne constitue pas un phénomène hétérogène, se manifestant différemment selon les caractéristiques de l’agresseur sexuel. Les résultats susmentionnés et leurs implications théoriques et cliniques sont discutés. / To date, there has been no consensus in the literature on the characteristics of the sadistic sexual aggressor. This has been largely the result of the limitations of studies of this phenomenon (e.g., idiosyncratic definitions of sexual sadism, heterogeneous samples, temporality fixed at adulthood). In an effort to address these limitations, we identified the distinguishing features of sadistic (n = 69) and nonsadistic (n = 137) sexual aggressors against adult women, all of whom were incarcerated in Quebec (Canada), using the Severe Sexual Sadism Scale (SESAS), an empirically validated measurement instrument for sexual sadism, as well as other variables. Bivariate (chi-square) analyses revealed that sadistic and nonsadistic sexual aggressors of adult women differed in several ways, including developmental (e.g., victimization before age 18), psychological (e.g., personality, psychopathology), sexological (e.g., deviant sexual fantasies), and criminological (e.g., modus operandi). To determine whether sexual sadism is a heterogeneous phenomenon, latent class analyses were conducted on the SESAS items. These analyses revealed that sexual sadism is not heterogeneous, manifesting itself differently depending on the characteristics of the sexual aggressor. The above results and their theoretical and clinical implications are discussed.

This study was designed to empirically derive latent classes of mothers who were sexually abused during childhood and to assess the association between depression, alcohol/drug use, supportive intimate partner, and specific classes. One hundred six women between the ages of 20 and 44 years (M = 27) who reported having been sexually abused during childhood (CSA) and 158 non-CSA mothers between the ages of 20 and 43 years (M = 23) were interviewed and assessed along six parenting dimensions. Logistic regression models evaluated the association between psychoemotional variables and specific classes. The final model consisted of three classes--53.2%, 31.7%, and 15.2%. Alcohol/drug use was not statistically significantly associated with either class. Maternal depression and intimate partner support were differentially associated with the three parenting classes. Empirical support is provided for distinct classes of mothers sexually abused in childhood. The data-driven categorization of CSA mothers provides research and clinical directions for future parenting of survivors of childhood sexual abuse.

L’objectif de la présente étude est de soutenir l’utilisation d’une approche écologique pour l’analyse des données d’une évaluation standardisée. Nous implémentons cette approche en utilisant une Analyse de Classes Latentes (ACL) avec covariables sur les données du test de lecture du Programme d’Analyse des Systèmes Éducatifs de la CONFEMEN (PASEC) des élèves francophones de 6e année du primaire au Cameroun (N=617) et montrons comment une telle approche peut susciter un regard nouveau sur les résultats de cette évaluation. En effet, les programmes d’Évaluations standardisées à Larges Échelles (ELE) visent à évaluer les apprentissages et les compétences des individus et fournissent des données d’aide à la décision dans beaucoup de pays (Hogan, 2017 ; Loye, 2011 ; Wagemaker, 2014). Dans le cadre de ces ELE, les performances sont estimées uniquement sur la base des réponses que fournissent les candidats et donc de leurs capacités cognitives (Zumbo et al, 2015). Pourtant, de plus en plus de recherches suggèrent de considérer la performance à un test comme un phénomène qui se réalise dans un réseau interconnecté de connaissances, de caractéristiques individuelles et de contextes particuliers (McNamara, 2007 ; McNamara et Roever, 2006 ; Mislevy, 2018 ; Zumbo et al, 2015). L’approche écologique, qui s’inscrit dans cette perspective, s’intéresse aux hypothèses contextuelles, sociales et culturelles lors de l’estimation des performances à un test (McNamara, 2007 ; McNamara et Roever, 2006 ; Zumbo et al, 2015). Nos résultats mettent en évidence des écologies de performances en lecture qui varient en fonction des régions. Dans chacune de ces écologies, les profils de performances en lecture qui s’y dégagent dépendent des caractéristiques des élèves et des caractéristiques des milieux scolaires et extrascolaires dans lesquels ils évoluent. Nous mettons ainsi l’emphase sur le caractère situé des performances à un test permettant une lecture plus équitable des performances des différents candidats. Ce faisant, nous formulons des recommandations qui tiennent compte des réalités contextuelles des candidats contrairement aux recommandations uniformes souvent formulées à la suite des résultats aux ELE. / The purpose of this study is to support the use of an ecological approach for the analysis of standardized data assessment. This study is implimented by Latent Classes Analysis (ACL) with covariables on the test reading data of the « Programme d’Analyse des Systèmes Éducatifs de la CONFEMEN » (PASEC) french-speaking students of 6th grade primary school in Cameroon (N = 617) and shows how this approach can change the way we interpret the results of this study. Indeed, Standardized Large Scale Assessments (ELE) programs aim to appraise the learning and skills of individuals and provide decision support data in many countries (Hogan, 2017 ; Loye, 2011; Wagemaker, 2014). In the context of these ELEs, performance is estimated solely based on the responses provided by the candidates and therefore of their cognitive abilities (Zumbo et al, 2015). Yet a growing body of research suggests viewing test performance as a phenomenon that occurs in an interconnected network of knowledge, individual characteristics, and particular contexts (McNamara, 2007 ; McNamara and Roever, 2006 ; Mislevy, 2018 ; Zumbo et al. , 2015). The ecological approach, which is part of this perspective, is interested in the contextual, social and cultural hypotheses when estimating the performance of a test (McNamara and Roever, 2006 ; McNamara, 2007 ; Zumbo et al, 2015). Our results highlight reading performance ecologies that vary by region. In each of these ecologies, the reading performance profiles that emerge depend on the characteristics of the students and the characteristics of the school and out-of-school environments in which they operate. We therefore put the emphasis on the situated character of the performances on a test allowing a fairer reading of the performances of the different candidates. In doing so, we formulate recommendations that take into account the contextual realities of applicants, unlike the standard recommendations often made following ELE results.

No description available.

Abstract Objective The goal of this study is to uncover latent classes of maternal and paternal helicopter parenting among American and Chinese college students, and to examine whether latent classes of maternal and paternal helicopter parenting are related to college students’ mental health (depression and self-esteem). Background Previous studies have examined the association between helicopter parenting and college students’ well-being. However, less is known about how the multidimensional construct of helicopter parenting is related to college students’ mental health across Western and Eastern cultural contexts. Method We conducted three-step latent class analyses using nine helicopter parenting indicators for 1,386 mother–child and 1,214 father–child groups in the United States and 520 mother–child and 454 father–child groups in China. Next, we tested the association between the class membership of maternal and paternal helicopter parenting and college students’ mental health. Results We identified distinct helicopter parenting latent classes among four American and Chinese parent–child groups. We also found that American college students in the strong maternal helicopter parenting latent class reported poorer mental health than those in other latent classes. Conclusion Our findings indicate that the multidimensional construct of helicopter parenting can be interpreted differently by parents and college-aged children according to their social and cultural contexts. Implications The findings of this study suggest that it is necessary to strengthen understanding of the multidimensional construct of helicopter parenting for parents with college-aged children to enable them to develop more appropriate parenting practices as well as support their children's well-being.

No description available.

The aim of this study is to examine the public preferences for urban riparian corridors in arid ‎regions, by testing to what extent people are willing to trade-off unmaintained ecological ‎landscape for aesthetics offered by specific micro and ‎macro environmental factors. Landscape ‎design reflects ecological and aesthetic values, and trade-offs are often made ‎between the two in ‎‎practice. In arid regions, water scarcity means riparian corridors are the ‎richest landscape ‎typology and the only ‎blue-green links for hundreds of miles. Pressure from ‎urbanization and ‎lack of eco-literacy contribute to negative ‎feedback loops which present dire ‎challenges for ‎migrating avifauna and regional wildlife. Regarding natural ‎resources and ‎biodiversity, where ‎multiple deliverable ‎ecosystem services rely on the quality and health of that ‎‎ecosystem, riparian ‎systems with high biomass are more desirable. Although this can be ‎achieved with low or no ‎‎maintenance riparian buffers, these unmaintained ecological landscapes ‎play an intrinsic role in ‎sustaining the ‎global ecosystem services and are important for the survival of the inhabitants ‎‎(avifauna). Ecological ‎landscapes are often subjected to trade-offs with aesthetic ‎landscapes that ‎include micro and ‎macro environmental factors such as manicured landscapes. It is accepted that ‎‎there is a ‎preference for aesthetics in landscape design; however, it is unclear how laypeople ‎prioritize ‎aesthetics ‎over different ecological factors in landscape scenes. This study uses a ‎Discrete Choice ‎Experiment (DCE) to elicit the ‎preferences of current or pretendant residents of ‎Jeddah City, Saudi Arabia for multiple landscape scenes. The method ‎combines ecological ‎landscape characteristics adopted from ‎the QBR index that are found in the study area in Jeddah ‎and aesthetic ‎characteristics, such as micro and macro environmental factors that are commonly ‎suggested in landscape design projects adapted from relevant visual preference studies (Alsaiari, ‎‎2018; Kenwick et al., 2009; Kuper‎ ‎,‎2017; Zhao et al., 2017). ‎DCE is a widely used method to ‎reveal preferences by analyzing the trade-offs people make ‎between ‎alternatives. Participants in ‎this study were exposed to a set of designs, which included ‎various configurations of ‎aesthetic ‎and ecological elements. Participants' choices revealed the influence of their ecological and ‎‎aesthetic values. Results show that minimal design interventions would prevent trading off the ‎ecological unmaintained landscape and that there are four subgroups with distinct homogeneous ‎preferences for the attributes affecting the appeal for the urban riparian corridor in Jeddah City. ‎Finally, results show that even though there are significant differences between subgroups based ‎on preferences, the demographic information is proportionally distributed in a way the means ‎differences diminish between the subgroups. ‎Findings in this study will equip ‎decision-makers ‎with operational definitions relating to riparian ‎landscape design and a method ‎that they can use ‎to minimize losses in ecological value over aesthetic value. This study will help‎ ‎researchers and ‎landscape architects advance visual preference research further into the domain ‎of empirical ‎‎studies.‎ ‎ / Doctor of Philosophy / Landscape architecture is a profession that entails planning and design outdoor spaces, ‎‎landmarks, and ‎structures to improve the built environment and increasing the quality of ‎‎people's lives by achieving ‎environmental, social, economic, and aesthetic outcomes‎. The ‎profession often reflects ecological and ‎aesthetic values, and trade-offs are often made ‎between ‎the two in ‎practice. These ecological values ‎represent environmental characteristics that are ‎important for the survival of wildlife (protected path ‎and safe habitat) and the overall ecosystem ‎‎(every being has a role that sustain the health of the ‎environment). Culturally, human is ‎accustomed to a slick-and-clean (tamped) looking plant within urban ‎developments (i.e., ‎neighborhoods). An example of the trade-off that often happen in practice between ‎the ‎ecological and aesthetic values is replacing an ecologically unmaintained plants that play ‎important ‎ecological role (i.e., wildlife habitat) with clean tamped plants to increase the value of ‎a real estate. Due ‎to the uncertainty surrounding people's acceptance of the features of these ‎ecological unmaintained ‎plants, especially when it entails introducing ecological riparian ‎landscape attributes within ‎neighborhoods for the first time, this dissertation focuses on both ‎assessing ecological elements ‎preferences within an urban arid region in Jeddah, Saudi Arabia ‎and assessing the extent to which ‎advanced analytical methods are capable of providing a better ‎understanding of ecological riparian ‎landscape attributes preference differences among a ‎seemingly homogenous sample of participants. ‎The increasing usage of manipulated images in ‎choice tasks inspired this dissertation. The results of the ‎study demonstrate that among the ‎relatively homogenous sample of participants that was recruited, ‎four significant preference ‎patterns have emerged, which could be used to describe and predict ‎preference for ecological ‎riparian landscape attributes and choice with great accuracy. The dissertation ‎also investigates ‎policy implications that might be beneficial in creating a ‎physical environment that ‎match public ‎preferences. ‎It also offers research implications and recommendations for landscape ‎architects ‎and urban designers on how to employ visual choice experiments, which have been well-‎‎developed in other research field