516 research outputs found
Accounting for substitution and spatial heterogeneity in a labeled choice experiment
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labeled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.FWO grant number 12G5415
Accounting for substitution and spatial heterogeneity in a labeled choice experiment
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labeled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.FWO grant number 12G5415
Accounting for substitution and spatial heterogeneity in a labeled choice experiment
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labeled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.FWO grant number 12G5415
Accounting for substitution and spatial heterogeneity in a labeled choice experiment
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labeled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.FWO grant number 12G5415
Accounting for substitution and spatial heterogeneity in a labelled choice experiment
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labelled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.</p
Public preferences for river restoration: application of a labeled choice experiment in two Belgian river basins
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labeled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.FWO grant number 12G5415
Public preferences for river restoration: application of a labeled choice experiment in two Belgian river basins
No full textMany environmental valuation studies using stated preferences techniques are single-site studies that ignore essential spatial aspects, including possible substitution effects. In this paper substitution effects are captured explicitly in the design of a labeled choice experiment and the inclusion of different distance variables in the choice model specification. We test the effect of spatial heterogeneity on welfare estimates and transfer errors for minor and major river restoration works, and the transferability of river specific utility functions, accounting for key variables such as site visitation, spatial clustering and income. River specific utility functions appear to be transferable, resulting in low transfer errors. However, ignoring spatial heterogeneity increases transfer errors.FWO grant number 12G5415
Effectiveness of zinc fortified drinking water on zinc intake, status and morbidity of rural Kenyan pre-school children
No full text<strong>Background</strong>: Zinc deficiency is considered a significant public health problem in preschool children in Africa together with infections such as diarrhea, which further deplete the body of zinc. Young children are more vulnerable to zinc deficiency due to increased requirements and frequent infections. Zinc fortified water is one way of improving zinc intake and reducing diarrheal infections in such vulnerable groups. Vestergaard Frandsen has developed a point-of-use device capable of purifying and concomitantly fortifying water with zinc at concentration ranges of ≈ 1-4mg/L. This filter is meant for households in areas of poor socioeconomic status with limited access to improved water sources. The overall aim of this thesis is to assess the contribution that zinc fortified water can make to zinc intake and bioavailability in children aged 2-6 years old from rural Western Kenya. <strong>Methods: </strong>The investigations in this thesis comprise a cross sectional and effectiveness study conducted in rural Western Kenya and a stable isotope study conducted in Switzerland. Firstly we assessed the baseline prevalence of zinc, iron and vitamin A deficiency in 461 children aged between 2-6 years in rural Western Kenya in a cross sectional study. We conducted a stable isotope study in Swiss adults to determine bioavailability of zinc from zinc fortified water produced by a household water purification and fortification device – the Lifestraw Family filter (LSF filter). Furthermore we conducted laboratory trials to investigate effect of usage pattern and idle time on zinc elution levels. Next we investigated the effectiveness of daily consumption of zinc fortified water on zinc intake, zinc status and morbidity in rural Kenyan children 2-6 years old (n=184). Lastly we used dietary intake data of the children involved in the effectiveness trial to develop food based recommendations that should accompany the introduction of zinc fortified water to ensure overall nutrient adequacy. <strong>Results: </strong>The results indicated that zinc and iron deficiency were highly prevalent and affected 74% and 61% respectively of the children. Vitamin A deficiency affected 34% of the children. Inflammation was high in this population and applying published approaches to correct nutrient biomarker for inflammation led to varying estimates of deficiency. Percent decrease in zinc and vitamin A deficiency ranged from 2-19%, and 43-78% respectively, with iron deficiency (definition inclusive of soluble transferrin receptor) decreasing by 10% using exclusion method and increasing by range 0.6-3.6% by all other approaches. The stable isotope study showed that geometric mean (-SD, +SD) fractional absorption was 65.9% (42.2, 102.4) from fortified water, higher (p<0.01) than 9.8% (5.7, 16.7) and 9.1% (6.0, 13.7) when either water was fortified and consumed with maize or when maize was fortified and consumed with water, respectively (p<0.01). Zinc elution was higher in filters used to treat 2L/day (4.7±1.6mg/L) than 10L/d (1.7±0.9) and 20L/d (1.3±0.7mg/L) (p<0.05). Percent increase in zinc eluted after 1 week storage was 23.4% (2L/d), 82.4% (10L/d) and 43.1% (20L/d). After the second week of storage, zinc elution further increased by 56.9% (2L/d), 12.9% (10L/d) and 7.5% (20L/d), compared to previous week of continuous usage. Daily consumption of zinc fortified water at the rate ≈461ml/d per child, contributed 42% and 36% of daily requirements for absorbable zinc in children 2-3 and 4-6 years respectively. Zinc fortified water decreased overall morbidity (RR=0.91; 95%CI: 0.87, 0.96), morbidity due to colds (RR=0.91; 95%CI: 0.83, 0.99) and stomach pain (RR =0.70; 95%CI: =0.56, 0.89) and a significant reduction for diarrhea in the per protocol analysis, (RR=0.72; 95%CI: =0.53, 0.96). There was no treatment effect on plasma zinc concentration and stunting. The final set of FBRs developed comprised unfortified whole grain products (14 serves per week), unfortified fluid or powdered milk (7 serves per week), nuts and seeds (4 serves per week), vitamin A rich vegetables (7 serves per week), other starchy plants (7 serves per week), vitamin C rich vegetables (7 serves per week) and small whole fish with bones (7 serves per week). These FBRs achieved nutrient adequacy for all nutrients except for vitamin A (25%RNI) and folate (68%RNI). <strong>Conclusion: </strong>We have shown that in areas at elevated risk of zinc deficiency and with limited access to improved water sources, daily consumption of zinc fortified water contributes substantially to daily zinc intake and is effective in reducing prevalence of common infectious morbidity in children. A single nutrient intervention such as zinc fortified water must be accompanied by food based recommendations in order to fulfill nutrient gaps as these communities often suffer from multi micronutrient deficiencies. In areas with high prevalence of deficiencies, correcting nutritional biomarker for inflammation does not change the conclusion that deficiency levels are of public health relevance
Dependently Typed Languages in Statix
No full textStatic type systems can greatly enhance the quality of programs, but implementing a type checker that is both expressive and user-friendly is challenging and error-prone. The Statix meta-language (part of the Spoofax language workbench) aims to make this task easier by automatically deriving a type checker from a declarative specification of a type system. However, so far Statix has not been used to implement dependent types, which is a class of type systems which require evaluation of terms during type checking. In this paper, we present an implementation of a simple dependently typed language in Statix, and discuss how to extend it with several common features such as inductive data types, universes, and inference of implicit arguments. While we encountered some challenges in the implementation, our conclusion is that Statix is already usable as a tool for implementing dependent types
Erlebnis-Raum in 'Der Garten' und 'Heufieber'
No full textNormalerweise erfolgt die Situierung des Betrachters zur gebotenen Bildwelt über die Perspektivierung, beispielsweise durch die Zentralperspektive, die dem Publikum einen bestimmten Blickpunkt zuweist. Mit zeitbasierten Arbeiten ist es hingegen möglich, entweder die Perspektivierung als eine dynamisierte zu exemplifizieren oder Veränderungen des Blickpunktes über die Art der gezeigten bildlich-motivischen Dynamik in der Rezeption zu provozieren. Der Beitrag zielt darauf ab, verschiedene Weisen der Verschränkung zwischen Perspektivierung und Bildzeitlichkeit zu thematisieren. Die künstlerische Animation Der Garten macht mit bildnerischen Mitteln erfahrbar, dass eine intensive Auseinandersetzung mit der Umwelt letztere für die Tätigen je unterschiedliche Qualitäten annimmt. Zur Verdeutlichung wird der Darstellungsraum mit den Handlungen der Protagonistin korreliert und damit auch dynamisiert. Die zweite besprochene Arbeit, das Video Heufieber, funktioniert insofern analog, als dass das im ersten Beispiel gezeigte Motiv einer Weltgestaltung nun in die Rezeption verlagert ist und somit als Erfahrung nicht mehr für andere externalisiert wird. Der antizipierte aktive Betrachter moduliert seinen Raumeindruck aufgrund der gesammelten Erfahrungswerte angesichts von Abläufen. Um das komplexe Phänomen zu umkreisen, werden theoretische Positionen aus unterschiedlichsten Gebieten herangezogen: Über die Beobachtung (zweiter Ordnung) und Niklas Luhmann lässt sich Handeln und Betrachten verschränken, mit Henri Bergson wird die qualitative Auffassung von Raum denkbar und schließlich bietet Ludwig Wittgenstein neben der Gestaltpsychologie über den Aspektwechsel ein theoretisches Instrumentarium, um die festgestellten Bildraumumschwünge in Heufieber zu charakterisieren
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