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Le dépistage du cancer de la prostate est largement controversé de par l’équilibre de la balance bénéfices-risques de cette procédure. L’enjeu de santé publique est alors d’accompagner au mieux les hommes susceptibles de se faire dépister pour qu’ils puissent être informés et participer au choix. L’objectif de ce doctorat est de contribuer à comprendre pourquoi les hommes participent au dépistage du cancer de la prostate, pour pouvoir améliorer dans un second temps leur accompagnement. Nous avons tout d’abord interrogé des hommes sur leurs connaissances, leurs sources d’informations et leur rôle dans le choix de participer au dépistage du cancer de la prostate. Ces entretiens ont abouti à la nécessité de concevoir un nouvel outil d’information pour améliorer les connaissances des hommes, en particulier sur les risques de la procédure de dépistage. Enfin, nous avons estimé comment les bénéfices et les risques étaient intégrés dans le choix des individus selon si ces derniers avaient eu accès à notre outil d’information. Les résultats de ce travail montrent que les hommes semblent moins favorables à une proposition de dépistage après avoir eu accès à notre outil d’information. Cependant, cela ne modifie pas leur appréciation des bénéfices et des risques du dépistage. Il est nécessaire de poursuivre les efforts pour permettre aux hommes de faire un choix éclairé. / Prostate cancer screening is highly controversial because of the benefit risk ratio. An issue is to support men susceptible to perform this screening towards informed choice and shared decision-making. The aim of this doctorate is to understand why men adhere to prostate cancer screening, and in a second time to improve their support. We interviewed men about their knowledge, their information seeking behaviour, and their implication in prostate cancer screening decision. This highlighted the necessity to create a new information tool to improve men’s knowledge, in particular regarding risks of the screening procedure. Finally, we investigate benefit risk trade-off with and without our information tool access. Results of this work shows that men are less favourable to a screening option after taking into account our information tool. However, benefit and risk of this screening appreciation was not changed. We need to continue efforts to allow men to make an informed choice.

The overall goal of this study was to analyse the welfare effect of improved wastewater treatment with the view of making policy recommendations for sustainable urban and peri-urban irrigation agriculture in Kenya. This goal was achieved by investigating three specific objectives. The first objective was to assess the farmers’ awareness of health risks in urban and peri-urban wastewater irrigation. Second objective was to analyse the factors that affect the choice of low-risk adaptations in reuse of untreated wastewater for irrigation. The third objective was to estimate the value that urban and peri-urban farmers who practice wastewater irrigation impute to improvements in specific characteristics of the wastewater input in agriculture. In order to achieve the first objective, an ordered probit model was used to identify the factors that influence farmers’ awareness of health risks in untreated wastewater irrigation. The model was fitted to data collected from a cross-sectional survey of 317 urban farm households in the Kibera informal settlement of Kenya. Results of this study show that gender of household head, household size, education level of household head, farm size, ownership of the farm, membership to farmers’ group, and market access for the fresh produce significantly affect awareness of farmers about health risks in wastewater irrigation. Therefore, there is need for awareness programs to promote public education through regular training and local workshops on wastewater reuse in order to improve the human capital of the urban and peri-urban farmers. To achieve the second objective, the study used a multinomial logit model to analyse the farmers’ choice of low-risk adaptations in untreated wastewater irrigation. A survey of 317 urban and peri-urban farmers was conducted and measures for risk-reduction in wastewater reuse were analysed. The urban and peri-urban farmers were found to have adopted low-risk wastewater irrigation techniques such as cessation of irrigation before harvesting, crop restriction and safer application methods. Results of the study show that adoption of risk-reduction measures is significantly influenced by the following factors: household size, age of the household head, education of household head, access to extension, access to media, access to credit, farmers’ group membership, and risk awareness. Also, marginal analysis of the coefficients confirmed the socio-economic characteristics are key determinants in adoption of low-risk measures in wastewater reuse. The study recommends that policies in support of low-risk urban and peri-urban irrigation agriculture should disaggregate farmers according to their socio-economic and institutional characteristics in order to achieve their intended objectives. To achieve the third objective, the study employed the discrete choice experiment approach to estimate the benefits farmers impute to improvements in attributes of the wastewater irrigation input, whose aim is to reduce the health risks associated with untreated wastewater irrigation. Urban and peri-urban farmers who practice wastewater irrigation drawn from Motoine-Ngong River in Nairobi were randomly selected for the study. A total of 241 farmers completed the presented choice cards for the choice model estimation. A random parameter logit model was used to estimate the individual level willingness to pay for wastewater treatment. The results show that urban and peri-urban farmers are willing to pay significant monthly municipality taxes for treatment of wastewater. Conclusion of this study was that, quality of treated wastewater, quantity of treated wastewater and the riverine ecosystem restoration are significant factors of preference over policy alternative designs in wastewater treatment and reuse. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Agricultural Economics, Extension and Rural Development / unrestricted

Das Ziel der Masterarbeit ist es zu klären, ob private Haushalte variable Strompreise akzeptieren und die Stärke der charakteristischen Merkmale zu ermitteln. Der dazu benötigte Datensatz wurde mit Hilfe einer Stated Choice Befragung im Internet ermittelt. Dafür wurden drei Gerätekategorien und ein Dreitarifmodell formuliert. Für die Auswertung wurde ein additiv verknüpftes Teilwert-Nutzenmodell und ein binäres Logit-Choice-Modell verwendet. Signifikante Variablen wurden über das Top-down-Verfahren bestimmt. Das Modell und die Schätzer der Preise wurden im Anschluss durch Hypothesentest getestet. Als signifikante Schätzer, mit stark negativen Werten, stellten sich in allen Kategorien die Preise heraus. Die Hypothesentests ergaben, dass es sinnvoll ist, die Schätzer der Preise für die ersten beiden Gerätetypen zusammenzufassen. Es stellte sich eine unterproportionale Preiselastizität der Nachfrage heraus und eine hohe Akzeptanz ein Teil der Geräte in den Nachtstunden zu nutzen. Insgesamt sprachen sich mehr Teilnehmer für ein Smart-Meter-Gateway aus als dagegen.:Kurzfassung I Abstract I Themenbeschreibung für eine Forschungsarbeit II Inhaltsverzeichnis III Abbildungsverzeichnis V Tabellenverzeichnis VI Abkürzungsverzeichnis VII 1. Einleitung - 1 - 2. Gegenwärtiger Strommarkt - 3 - 2.1 Aufbau der Elektrizitätswirtschaft - 3 - 2.2 Strombörse - 5 - 2.3 Preisbildung des Stroms - 8 - 3. Nutzung variabler Strompreise - 13 - 3.1 Probleme und Gestaltung eines zukünftigen Strommarktes - 14 - 3.2 Funktionsweise des Demand Side Management - 19 - 3.3 Ausblick auf zukünftige Tarife - 25 - 3.4 Aufbau einer zukünftigen überregionalen und häuslichen Energieinfrastruktur - 28 - 3.5 Bandbreite möglicher Speichertechnologien des zukünftigen Strommarktes - 32 - 4. Theoretische Grundlagen - 39 - 4.1 Stated Preference vs. Revealed Preference - 39 - 4.2 Conjoint-Analyse - 40 - 4.3 Diskrete Wahlmodelle - 42 - 5. Hintergründe zur Erstellung des Fragebogens - 50 - 6. Modellspezifikation - 53 - 7. Analyse der Umfrage - 57 - 7.1 Auswertung des Modells - 57 - 7.2 Teststatistik - 62 - 8. Interpretation der Ergebnisse - 66 - 9. Fazit - 68 - Literaturverzeichnis IX Anhang XIV Erklärung zur Urheberschaft XXII / The aim of the master thesis is to clarify whether private households accept variable electricity prices and determine the strength of the characteristic attributes. The data set was determined with a Stated Choice survey on the Internet. For this purpose, three device categories and a three-tariff model were formulated. An additive-linked partial-value model and a binary logit choice model were used for the evaluation. Significant variables were determined by using the top-down method. Afterwards the model and the estimators of the prices were tested with statistical hypothesis testings. The price emerged as a significant estimator, with strongly negative values in all categories. The hypothesis tests showed that it is useful to conclude the estimators of the prices for the first two device types. The results showed an inelastic price elasticity of demand and a high acceptance of the subjects to use a part of the devices in the night hours. Overall, more participants decide to use a smart meter gateway than to refuse it.:Kurzfassung I Abstract I Themenbeschreibung für eine Forschungsarbeit II Inhaltsverzeichnis III Abbildungsverzeichnis V Tabellenverzeichnis VI Abkürzungsverzeichnis VII 1. Einleitung - 1 - 2. Gegenwärtiger Strommarkt - 3 - 2.1 Aufbau der Elektrizitätswirtschaft - 3 - 2.2 Strombörse - 5 - 2.3 Preisbildung des Stroms - 8 - 3. Nutzung variabler Strompreise - 13 - 3.1 Probleme und Gestaltung eines zukünftigen Strommarktes - 14 - 3.2 Funktionsweise des Demand Side Management - 19 - 3.3 Ausblick auf zukünftige Tarife - 25 - 3.4 Aufbau einer zukünftigen überregionalen und häuslichen Energieinfrastruktur - 28 - 3.5 Bandbreite möglicher Speichertechnologien des zukünftigen Strommarktes - 32 - 4. Theoretische Grundlagen - 39 - 4.1 Stated Preference vs. Revealed Preference - 39 - 4.2 Conjoint-Analyse - 40 - 4.3 Diskrete Wahlmodelle - 42 - 5. Hintergründe zur Erstellung des Fragebogens - 50 - 6. Modellspezifikation - 53 - 7. Analyse der Umfrage - 57 - 7.1 Auswertung des Modells - 57 - 7.2 Teststatistik - 62 - 8. Interpretation der Ergebnisse - 66 - 9. Fazit - 68 - Literaturverzeichnis IX Anhang XIV Erklärung zur Urheberschaft XXII

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<p>QC 20130524</p>

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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

In traditional investment decision making, one tool commonly used is the mean variance model, also known as an expected-value variance (EV) model, which evaluates the anticipated payout of different assets with respect to uncertainty where portfolios with higher risk demand higher expected returns from an individual. This thesis adapts this framework to a cost setting where decision makers are evaluating alternative physical assets that carry lifetime cost uncertainty for maintenance. Specifically, this paper examines homeowner choices for their home plumbing systems in the event of a pinhole leak, a tiny pin-sized hole that forms in copper, drinking-water pipes. These leaks can cause substantial damage and cost homeowners thousands of dollars in repairs. Since pinhole leaks are not related to the age of pipe material, a homeowner is subject to the risk of additional costs if a pinhole leak occurs again despite their repair efforts. The EV cost model in this paper defines two discrete choices for the homeowner in the event of a leak; to apply a simple repair at lower cost and higher future cost uncertainty, or to replace their plumbing with new pipe material, usually made of plastic, at a higher upfront cost but lower likelihood of future expenses. The risk preference of homeowners are demonstrated by their repair strategy selection, as well as the level of cost they incur to reduce uncertainty. Risk neutral individuals will select the repair strategy with the lowest lifetime expected cost and high variance, while risk averse homeowners will prefer to replace their plumbing with higher cost but lower variance. Risk averse individuals are also exposed to indirect costs, which is an additional unobserved cost in the form of a risk premium the homeowner is willing to pay to remove all uncertainty of future pinhole leak expense. Expected costs and variances are also higher for regions in the U.S. that experience elevated leak incident rates, known as hotspots. Using this mean variance cost framework, indirect cost can be quantified for homeowners in hotspot regions and compared to the rest of the U.S. to evaluate the magnitude of pinhole leak risk. The EV cost model estimates risk premiums on pinhole leaks to be $442 for homeowners in hotspots and $305 for those in the rest of the U.S. Finally, this paper examines the impact of pinhole leak cost uncertainty on the U.S. economy. Of an estimated $692 million in annual pinhole leak costs to homeowners, this study estimates a lower bound cost of $54 million per year (7.8% of estimated national annual cost) in risk premium that homeowners would be willing to pay to avoid pinhole leak cost uncertainty. Information in this study on the role of risk in home plumbing decisions and indirect costs would be helpful to policymakers and water utility managers as they deal with infrastructure management decisions. Furthermore, the EV cost methodology established in this paper demonstrates an effective use of mean variance modeling under cost uncertainty. / Master of Science