Text in English, Zulu and Afrikaans / The study investigated assistive technology for the deaf, specifically applied to the teaching and learning of mathematics at a rural Namibian special primary school. The problem was the lack of prior research about the effects of Constructivist assistive technology for guiding Namibian special schools and educators. The objective was to conduct an experiment with deaf learners and interviews with the teachers involved. The study was a mixed methods study, involving quantitative academic achievement data and qualitative interview data. The findings suggest that there was a statistically significant effect on the multiplication and division achievement of the learners, but not their addition and subtraction achievement. The emergent Constructivist-related categories were collaborating, cooperating, exploring, selfassessing, learning from errors, seeking knowledge independently, self-regulating, selfreflecting, metacognitive thinking and being self-aware. These scientific insights contribute to the field and stem from a useful method for reviewing and selecting an appropriate learning theory and assistive technology. / Isifundo socwaningo siphenya ngobuchwepheshe obuluncedo kulabo abayizimpumputhe, ikakhulukazi lolu cwaningo lumayelana nokufundisa kanye nokufundwa kwesifundo sezibalo esikoleni sabakhubazekile endaweni yasemakhaya ngaseNamibia. Inkinga lapha ukusweleka kocwaningo lwangaphambili olumayelana nemithintela yohlelo lobuchwepheshe oluncedayo losolwazi abangama-contructivists ngokuhola izikole zabakhubazekile zaseNamibia kanye nabafundisi. Inhloso kwaye kuwukwenza ucwaningo oluphathekayo kanye nabafundi abakhubazeke amehlo kanye nenhlolovo nothisha ababandakanyekayo, ngokusebenzisa ucwaningo oluxubile, oluxuba idatha mayelana nempumelelo kwezemfundo kanye nedatha yezamanani yenhlolovo. . Okutholwe wucwaningo kuchaza ukuthi kunomthelela obonakalayo wezamanani mayelana nempumelelo yekhono lokuphindaphinda kanye nokwehlukanisa, kodwa hayi impumelelo yabo ngokwekhono lokuhlanganisa kanye nokunciphisa. Izigaba ezihambisana nosolwazi abakhasayo zisebenza ngokuncedana, ngokusebenzisana, ngokuvumbulula, ngokuzihlola wena siqu sakho, ngokufunda ngokwenza amaphutha, ngokucinga ulwazi ngokuzimela, ngokuzenzela imigomo, ngokubheka impumelelo yakho, ngokucabangisisa ngokusebenzisa ulwazi kanye nokuzibhekisisa. Lolu lwazi lwezesayensi lunomthelela emkhakheni kanti lususelwa endleleni esebenzayo ngokubuyekeza kanye nokukhetha ithiyori yokufunda efanele kanye nohlelo oluncedayo lobuchwepheshe. / Die studie het ’n ondersoek na bystandstegnologie vir dowes, spesifiek ten opsigte van hoe dit in die onderrig en leer van wiskunde by ’n landelike spesiale laerskool in Namibië toegepas word, behels. Die navorsingsprobleem was die gebrek aan navorsing oor die effek van konstruktivistiese bystandstegnologie wat leiding aan Namibiese spesiale skole en opvoeders kan bied. Die navorsingsdoelwit was om ’n eksperiment met dowe leerders uit te voer en onderhoude met die betrokke onderwysers te voer as deel van ’n gemengdemetodestudie, wat die insameling van kwantitatiewe data oor akademiese prestasie en kwalitatiewe onderhouddata behels het. Die bevindings van die studie dui op ’n statisties beduidende effek op die leerders se prestasie met betrekking tot vermenigvuldiging en deling, maar nie hulle prestasie met betrekking tot optel en aftrek nie. Die voortkomende konstruktivisties-verwante kategorieë is meewerking, samewerking, verkenning, selfassessering, die vermoë om uit foute te leer, ’n onafhanklike soeke na kennis, selfregulering, selfbesinning, metakognitiewe denke en selfbewussyn. Hierdie wetenskaplike insigte lewer ’n bydrae tot die studieveld en spruit uit ’n nuttige metode vir die beoordeling en seleksie van geskikte leerteorieë en bystandstegnologie. / School of Computing / M. Sc. (Computing)

Three of Impatiens species are widespread in the Czech republic, one is native, two of them invasive. Because all species occur in relatively similar habitats, the question is, whether the invasive species can negatively affect the native species, or even the original can can be displaced. The aim of the thesis was: (i) to compare habitat requirments of the Impatiens species, (ii) to determine if the coexistence of species is possible, (iii) to assess the impact of invasive species to the original species. The investigation was carried out using two sets of permanent plots in 5 localities. In the first set with a total of 84 plots (combinations of occurrence of the three species) site characteristics as tree cover, soil humidity, slope and bare land cover were directly measured and nutrient, light, humidity and soil reaction characteristic assessed using Ellenberg indicator values. The second set contained a total of 45 plots with one of the native-invasive congener pair being removed and the intact controls. Number, cover and height of the plants were assesed. The key enviromental factors determining distribution of the species were soil moisture for I. noli-tangere and I. parviflora, and tree cover for I. glandulifera and I. parviflora. Ellenberg indicator values had poor explanation value;...

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This article investigates the decision of consumers at bottle refund machines to either reclaim their bottle deposit or to donate the refund to a non-profit organization. The study documents the unique pre-intervention data on donating behaviour and introduces a field experiment to increase donation levels. The design comprised the strategic framing of the situation by highlighting different cues about the normative, descriptive and local expectations of charitable giving as well as cues about the warm glow of donating money. The experiment took place in 20 supermarkets in Germany and lasted for 12 months. By varying the experimental design and using different modelling approaches, the study arrives at the conclusion that individuals largely act consistent with the assumption having self-regarding preferences that are stable and difficult to change. Hence, our pre-test and postintervention data stand in sharp contrast to results from lab experiments.

Indiana University - Purdue University - Indianapolis (IUPUI) / This philanthropic studies thesis aims to “increase the understanding of philanthropy, improve its practice, and enhance philanthropic participation” (Center on Philanthropy at Indiana University Overview) by studying the effects of social information, social norms and social identity on giving. It connects philanthropic studies research with theoretical developments in motivations for giving in economics, nonprofit management, nonprofit marketing, consumer behavior, and social psychology. It utilizes personal observations as well as quantitative methods including experiments and surveys on multiple samples including donors, undergraduate students and samples of the U.S. population. It generates actionable and efficacious knowledge to improve the practice of philanthropy. It contributes to the formation and growth of the young field called philanthropic studies - in theory, in methodology and in practice. This thesis includes five chapters. Chapter I will explain how the research question, philosophy and methodology are selected. This discussion will be for the entire thesis. Specific research questions, hypotheses, research designs, findings and implications will be explained in the subsequent chapters. Chapter II demonstrates the immediate and long-term effects of social information on donations and its boundary conditions in existing nonprofit donors in two field experiments. Chapter III shows that the psychological mechanism through which social information influences subsequent giving is perceived descriptive social norms in one field survey of donors and one laboratory experiment on undergraduate students. Chapter IV investigates how social identity congruency moderates the effect of social information on donations. It reports three field experiments on donors and samples of the general U.S. population and two laboratory experiments on undergraduate students. It shows that donors give more money to a public radio station if told that a previous donor with a similar identity also made a large contribution. This effect is more likely to occur when donors have high collective identity esteem and when attention is focused on others. Each chapter provides original fundraising techniques developed from these studies. Chapter V concludes with a discussion of the theoretical, methodological and practical contributions of this thesis and suggests directions for future research in philanthropic studies, and philanthropic psychology in particular.

Phytoplankton blooms compromise the quality of freshwater ecosystems and the efficient processing of water by treatment works worldwide. This research aims to determine whether in-situ filamentous biofiltration processes mediated by living roots and synthetic filters as media can reduce or remove the phytoplankton loading (micro-algae and cyanobacteria) prior to a potable water treatment works intake. The underlying biofiltration mechanisms were investigated using field and laboratory studies. A novel macroscale biofilter with three plant species, named the "Living-Filter", installed in Farmoor II reservoir, UK, was surveyed weekly for physicochemical and biological variables under continuous flow conditions during 17 weeks. The efficiency of a mesoscale biofilter using the aquatic plant Phalaris arundinacea and synthetic filters, was tested with Microcystis aeruginosa under continuous flow conditions and in batch experiments. The 'simultaneous allelochemical method' was developed for quantifying allelochemicals from Phalaris in aqueous samples. Microscale studies were used to investigate biofilter allelochemical release in response to environmental stressors and Microcystis growth inhibition in filtered and unfiltered aqueous root exudate. Results demonstrate that the removal of phytoplankton biomass by physical mechanisms has a removal efficiency of ≤45% in the "Living-Filter" (filamentous biofilter plus synthetic fabric) and that the removal of Microcystis biomass using only biofilters was 25%. Chemical mechanisms that reduce Microcystis cell numbers are mediated by allelochemicals released from biofilter roots. Root exudate treatments on Microcystis revealed that Microcystis growth is inhibited by allelochemicals, not by nutrient competition, and that protists and invertebrates play a role in removing Microcystis. Filamentous biofilters can remove phytoplankton biomass by physical, chemical and biological mechanisms. Biofilters and synthetic filters in combination improve removal efficiency. Application of macroscale biofilters prior to potable water treatment works benefits the ecosystem. Plant properties, biofilter size to surface water ratio, and retention time must be considered to maximise the benefits of biofiltration processes.

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Cette thèse traite des mesures à prendre afin d'assurer le succès de projets de développement exécutés par des firmes privées, et plus particulièrement les Organisations Non Gouvernementales (ONGs). Les ONGs sont des firmes à but non lucratif qui sont semblables aux gouvernements dans leur préoccupation pour le bien-être des bénéficiaires et aux firmes privées standard sur le plan organisationnel. Leur participation aux projets de développement soulève la question de savoir si elles sont plus efficaces que ces entités similaires. Malgré la croissance rapide du secteur ONG, surtout des multinationales basées dans les pays riches avec des branches implantées dans les pays pauvres, peu de recherches en économie de développement se sont intéressées à comment la nature d’une organisation peut affecter son comportement dans l’implémentation des projets de développement. Les trois chapitres de cette thèse soulignent des différences entre Les ONG, les firmes privées et les gouvernements et examinent comment la nature même de chaque type d'organisation affecte sa fourniture de services publics. Les deux questions-clés sont donc pourquoi et sous quelles des conditions choisir une ONG comme fournisseur de biens et services dans le cadre d'un projet de développement, et comment s’assurer que les normes culturelles des bénéficiaires n’affectent négativement la réussite desdits projets. / This thesis addresses the question of how to ensure the success of development projects executed by private firms, especially Non-Governmental Organizations (NGOs). NGOs are non-profit firms that are similar to governments in their concern about beneficiaries' welfare and to standard private firms in their organizational form. Their involvement in development projects raises the issue of how well they perform in service provision compared to alternative entities. Despite the rapid growth of the non-profit sector, especially international firms based in high-income countries that operate in low-income countries, the existing literature on economic development has hardly investigated the issue of non-profit performance and regulation. The three chapters of this thesis emphasize differences between NGOs and either private for-profit firms or governements, and examine how the very nature of each type of organization affects service provision. The two key questions are why and under which conditions to choose an NGO as goods or services provider in the framework of a development project, and how to ensure beneficiaries' cultural norms do not undermine the success of development projects.

Cette thèse porte sur la façon dont les individus prennent des décisions en présence de risque et d'incertitude. Elle est composée de quatre essais qui étudient théoriquement et expérimentalement la prise de décision.Les deux premiers essais étudient des situations où un décideur doit décider si un événement a eu lieu en utilisant des informations incertaines. Le fait d'identifier correctement que cet événement s'est produit est plus rémunéré que le fait d'identifier correctement qu'il ne s'est pas produit. Ce problème de décision induit une divergence entre deux qualités d'une décision : l'optimalité et l'exactitude. Les deux essais reproduisent de telles situations dans une expérience de laboratoire basée sur des tâches perceptuelles et analysent les décisions en utilisant la théorie de la détection du signal pour étudier l'arbitrage optimalité-exactitude. Le premier essai confirme l'existence d'un tel arbitrage avec un rôle dominant de la recherche de l'exactitude. Il explique l'existence de cet arbitrage par utilité non-monétaire associée au fait d'avoir raison. Le deuxième chapitre montre que présenter les informations perceptuelles en dernier contribue à l'existence de l'arbitrage optimalité-exactitude.Le troisième essai étudie comment les préférences vie-à-vie d'autrui interagissent avec l'attitude face à l'ambiguïté. Il présente les résultats d'une expérience où les sujets doivent faire des dons à des associations caritatives. Les dons peuvent avoir des coûts ou des bénéfices ambigus. Nous constatons que l'ambiguïté a pour effet de rendre les individus plus égoïstes. En d'autres termes, nous montrons que les individus utilisent l'ambiguïté comme une excuse pour ne pas donner. Ce comportement d’auto-justification est plus marqué pour les coûts ambigus que pour les avantages ambigus.Le quatrième essai examine la validité externe des mesures de préférence pour le risque en laboratoire en utilisant des décisions dans d'autres tâches expérimentales risquées et des décisions prisent sur en dehors du laboratoire. Nous constatons que les mesures de préférence pour le risque permettent d'expliquer les premières, mais qu'elles n'expliquent pas les secondes. / This thesis investigates how individuals make decisions under risk and uncertainty. It is composed of four essays that theoretically and experimentally investigate decision-making.The first two essays study situations where a decision maker has to decide whether an event has occurred using uncertain evidence. Accurately identifying that this event has occurred is more rewarded than accurately identifying that it has not occurred. This decision problem induces a divergence between two qualities of a decision: optimality and accuracy. Both essays reproduce such situations in a laboratory experiment based on perceptual tasks and analyze behavior using Signal Detection Theory to study the optimality-accuracy trade-off. The first essay confirms the existence of the trade-off with a leading role of accuracy. It explains the trade-off by the concern of individuals for being right. The second chapter finds that presenting perceptual evidence last contributes to the existence of the optimality-accuracy trade-off.The third essay studies how other-regarding preferences interact with attitude toward ambiguity. It reports the results of an experiment where subjects have to make donations to charities. Donations may have either ambiguous costs or ambiguous benefits. We find that other-regarding preferences are decreased under ambiguity. In other terms, we highlight that individual use ambiguity has an excuse not to give. This excuse-driven behavior is stronger for ambiguous costs than ambiguous benefits.The fourth essay challenges the external validity of laboratory risk preference measures using behavior in experimental risk tasks and naturally occurring behavior under risk. We find that risk preference measures are related with the former but that they fail to explain the latter.

Modern agriculture is causing a wide range of environmental problems. By regulating the agricultural sector, human societies try to find a balance between enabling the production of food and public goods and preventing negative consequences for the environment. In the European Union this is mainly achieved through the Common Agricultural Policy (CAP). Since many of the environmental indicators are still showing negative trends, an ongoing evaluation and adaptation of the policy instruments included in the CAP is asked for. At the same time, the field of policy evaluation is more and more incorporating a behavioral economic perspective on human behavior, one that deviates from the homo oeconomicus model that has long dominated research in this area. This thesis presents a study on “Behavioral Economics of Agri-Environmental Policies” by combining themes from agricultural and environmental economics with methods and perspectives from behavioral and experimental economics. It thereby contributes to the emerging field of behavioral agricultural economics. Specifically, it aims to shed light on the behavioral drivers of pro-environmental decisions of farmers and how these insights can be used to evaluate and adapt the CAP. With a lab-in-the-field experiment with farmers from Lower Saxony in Germany, an influence of the framing of the farmers’ societal role, their self-identity, as well as control aversion and feelings of warm glow on farmers’ behavior was uncovered. From a policy perspective, the results of this thesis provide a case for the continued use of both mandatory and voluntary policy instruments. Furthermore, with a Principal Components and Cluster Analysis, a multi-facetted picture of different farmer self-identities prevalent in the sample population was revealed. Based on a literature review, the thesis also provides an analysis of how behaviorally-informed interventions might increase the environmental performance of the CAP in the future.