This database contains bibliographic descriptions of all Wageningen University PhD theses from 1920 onwards. It is updated on a daily basis by WUR Library.
Author abstracts and/or summaries are added to all descriptions. A link to the full text dissertation is added to the bibliographic description. In a few cases, no electronic version is available, mostly because of copyright issues.
Hard copies of all theses are available for loan at WUR Library. To request them, click the link Request this publication in the full record presentation. This is a fee based service.
community development - community involvement - acquired immune deficiency syndrome - human immunodeficiency viruses - households - community health - health - socioeconomics - social behaviour - tanzania - social capital - livelihoods - networks - Women Tanzania - Poverty Tanzania - AIDS (Disease) - AIDS (Disease) Social aspects - Poverty - Women
natural resources - natural resource economics - resource management - resource utilization - public ownership - rural development - community development - community involvement - china - guizhou - national wealth - community participation
Abstract: In wastewater treatment plants (WWTPs), large amounts of biological waste sludge are produced. In the Netherlands, the application of this sludge in agriculture or disposal in landfills is no longer allowed, mainly because of its high heavy metal content. The sludge therefore generally is incinerated. Sludge processing costs are estimated to be half of the total wastewater treatment costs. This thesis focuses on the application of aquatic worms to reduce the amount and volume of the excess sludge. Several worm species, belonging to the Aeolosomatidae, Tubificidae (including Naidinae) or Lumbriculidae have specific characteristics that could make them suitable for such an application
Abstract: Het gaat goed met de varens in de Nederlandse bossen. Zeventig procent van de soorten neemt toe in aantal. De groei is voor een belangrijke deel te danken aan nieuwe leefgebieden in de bossen van Flevoland, waar zich binnen enkele decennia `hotspots` voor varens ontwikkelden. Dat is op wereldschaal niet eerder vertoond. Tot die bevinding komt, na dertig jaar onderzoek, Piet Bremer in zijn proefschrift
Abstract: Metingen van neerslag boven land zijn van groot belang voor het voorspellen van het weer, en voor het begrip van de uitwisseling van water tussen het landoppervlak en de atmosfeer. Deze uitwisseling is weer zeer belangrijk in klimaatmodellen. Het is mogelijk om regen te meten met de bestaande infrastructuur voor de communicatie tussen mobiele telefoons. Dit concludeert Hidde Leijnse in zijn proefschrift 'Hydrometeorologische toepassingen van microgolf straalverbindingen: meting van verdamping en neerslag'. Verder is onderzocht welke theoretische onzekerheden er horen bij de regenschattingen met verschillende systemen
pectins - characterization - chemical structure - mass spectrometry - degradation - capillary electrophoresis
Abstract: Pectine wordt in levensmiddelen vooral gebruikt als geleermiddel, stabilisator of verdikkingsmiddel in producten zoals jam, yoghurtdranken, vruchten-zuiveldranken en ijs. Daarnaast is er in toenemende mate interesse in het mogelijk gezondheidbevorderend effect van dit polysaccharide. Kennis van de exacte structuur zal bijdragen aan het begrip van de fysiologische functie van pectine in de plant en aan een verdere optimalisering van industriële en medische toepassingen van dit polymeer. Om meer inzicht te krijgen in de structuur werden nieuwe LC-MS en CE-MS methoden ontwikkeld, waarmee verbindingen tussen verschillende structuurelementen konden worden aangetoond. Als gevolg van de verkregen inzichten over de opbouw van pectine, wordt een aanpassing aan het structuurmodel van pectine voorgesteld, waarbij homogalacturonan ketens zowel lineair als vertakt aan rhamnogalacturonan I worden gepositioneerd. De ontwikkelde methoden, kunnen worden toegepast in onderzoek gericht op de opheldering van techno- en biofunctionele eigenschappen van complexe polysaccharidestructuren.
ecosystems - vegetation - management - sustainability - species - species diversity - spatial distribution - botanical composition - remote sensing - spectral analysis - discriminant analysis
Abstract: Sustainable management of natural ecosystems requires comprehensive information on species distribution and composition. Remote sensing has the potential to improve the collection of information on species composition. Compared to other vegetation attributes plant species so far remained a difficult attribute to detect with remote sensing. Broad band remote sensing sensors, which have been used extensively for mapping of plant communities, are however not sufficiently sensitive to allow discrimination of individual plant species. The advent of hyperspectral and high spatial resolution sensors offers new opportunities in this respect
land use - planning - learning - society - farming systems - sustainability - models - decision making - farm enterprises - problem analysis - problem solving - netherlands - uruguay - modeling - sustainable land use
Abstract: Barriers in rivers severely obstruct fish migration. To mitigate the impact, different types of fishways have been developed to facilitate upstream movements of fish. In this PhD-thesis the effect of a series of V-stepped fishways alongside weirs in the regulated River Vecht, the Netherlands, was evaluated.
Abstract: Livestock production has been identified as a major source of nitrogen (N) losses in agro-ecosystems. N excreted in dung and urine contributes to environmental N pollution either as ammonia and N oxides in air, or as nitrate in soil and ground water. Therefore, it is important to reduce N output through animal excretions by improving N utilisation by the animal. Bovine N utilisation can be increased substantially through changing the composition of the diet. In many parts of Europe, a large proportion of the bovine’s diet consists of grass taken up by grazing. Manipulating the nutritional composition of grazed grass poses a complex challenge, since it is hard to control the diet under grazing as this depends on grassland management and environmental factors. The objective of this research was to investigate the efficacy of grassland management tools for manipulating herbage quality and to assess the subsequent effect on the N efficiency of grazing cows. In the literature review, three pathways were identified through which more efficient N utilisation by grazing bovines can be achieved by manipulation of the chemical composition of the grass forage: 1) matching protein supply to animal requirements, 2) balancing and synchronising carbohydrate and N supply in the rumen, and 3) increasing the proportion of rumen undegradable protein (RUP). Under grazing conditions, grassland management tools, such as the length of the regrowth period, defoliation height, fertiliser N application rate, and growing high-sugar grass cultivars, are the main tools to manipulate herbage quality and subsequent bovine N efficiency. A field experiment was carried out to study the effect of those grassland management tools on the chemical composition of lamina and sheath material. These results were used to design a model for predicting the efficacy of herbage management tools for affecting the quality of herbage ingested by cattle under strip-grazing management. This model was validated and connected to the Cornell Net Carbohydrate and Protein System model in order to evaluate the effectiveness of a) the grassland management tools and b) the herbage quality pathways on the N utilisation of grazing dairy cows. Within the modelled scenario the concentration of crude protein (CP) in the ingested dry matter (DM) was the main factor affecting N utilisation. Model predictions indicated that herbage should be managed to achieve a CP concentration of 130−150 g / kg DM in order to maximise the efficiency of N utilisation for milk production and minimise the proportion of N excreted in urine. Both N application rate and rotation length were shown to be effective tools for affecting the CP concentration of the intake and subsequent cow N utilisation. However, there was no effect of the high-sugar cultivar and defoliation height on cow N utilisation. Assessment of the effectiveness of the three herbage quality pathways for improving bovine N utilisation resulted in the following conclusions: 1) N utilisation is strongly related to the daily N intake (g / day), however, this seems more connected to the N concentration of the ingested DM (g / kg DM), rather than the actual daily N intake. Therefore, the effect is more related to the balance between energy and N (pathway 2). 2) The balance between N and energy is the most important herbage quality factor for improving bovine N utilisation. In contrast, the synchronisation between the release of energy and N seems to have little effect. 3) The proportion of protein in the form of RUP is not much affected by the herbage management tools, and is therefore not an effective pathway for improving the N utilisation of grazing cows. It is recommended that the model will be extended to include a herbage yield and intake component. This would allow the model to be used to design herbage management systems to optimise N utilisation on a yearly basis.
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