Evaluation of an evaluation list for model complexity

This study (‘WOt-werkdocument’) builds on the project ‘Evaluation model complexity’, in which a list has been developed to assess the ‘equilibrium’ of a model or database. This list compares the complexity of a model or database with the availability and quality of data and the application area. A model or database is said to be in equilibrium if the uncertainty in the predictions by the model or database is appropriately small for the intended application, while the data availability supports this complexity. In this study the prototype of the list is reviewed and tested by applying it to test cases. The review has been performed by modelling experts from within and outside Wageningen University & Research centre (Wageningen UR). The test cases have been selected form the scientific literature in order to evaluate the various elements of the list. The results are used to update the list to a new version

Peg Solitaire on Trees with Diameter Four

In a paper by Beeler and Hoilman, the traditional game of peg solitaire is generalized to graphs in the combinatorial sense. One of the important open problems in this paper was to classify solvable trees. In this thesis, we will give necessary and sufficient conditions for the solvability for all trees with diameter four. We also give the maximum number of pegs that can be left on such a graph under the restriction that we jump whenever possible

Towards a Soil Information System with quantified accuracy : a prototype for mapping continuous soil properties

This report describes the potential and functionality of software for spatial analysis, prediction and stochastic simulation of continuous soil properties using data from the Dutch Soil Information System (BIS). A geostatistical framework and R codes were developed. The geostatistical model of a soil property has a deterministic component representing the mean value within a soil category, and a stochastic component of standardized residuals. The standardized residuals are interpolated or simulated based on the simple kriging system. The software was tested in four case studies: exchangeable soil pH, clay content, organic matter content and Mean Spring Water table depth (MSW). It is concluded that the geostatistical framework and R codes developed in this study enable to predict values of continuous soil properties spatially, and to quantify the inaccuracy of these predictions. The inaccuracy of a spatial prediction at a certain location is quantified by the kriging variance, which can be interpreted as an indication of the uncertainty about the true value

Processivity in Bacterial Glycosyltransferases

Extracellular polysaccharides and glycoproteins of pathogenic bacteria assist in adherence, autoaggregation, biofilm formation, and host immune system evasion. As a result, considerable research in the field of glycobiology is dedicated to study the composition and function of glycans associated with virulence, as well as the enzymes involved in their biosynthesis with the aim to identify novel antibiotic targets. Especially, insights into the enzyme mechanism, substrate binding, and transition-state structures are valuable as a starting point for rational inhibitor design. An intriguing aspect of enzymes that generate or process polysaccharides and glycoproteins is the level of processivity. The existence of enzymatic processivity reflects the need for regulation of the final glycan/glycoprotein length and structure, depending on the role they perform. In this Review, we describe the currently reported examples of various processive enzymes involved in polymerization and transfer of sugar moieties, predominantly in bacterial pathogens, with a focus on the biochemical methods, to showcase the importance of studying processivity for understanding the mechanism

Licht of zwaar mesten van varkens

Een belangrijke vraag waarvoor de varkenshouder zich steeds weer ziet geplaatst is tot welk gewicht de dieren dienen te worden gemest om een zo hoog mogelijk inkomen te behalen. Indien de varkens op een hoger gewicht worden afgeleverd is in het algemeen de geldopbrengst groter. Hier staat tegenover dat de kosten eveneens hoger zijn. Bij welk gewicht de rentabiliteit het grootst is hangt af van de mate waarin opbrengsten en kosten toenemen

On the reactivity and selectivity of donor glycosides in glycochemistry and glycobiology

The processes of glycosidic bond formation and destruction are a central theme in glycochemistry and glycobiology, and form the basis of the research described in this Thesis. In the first part, studies towards the stereoselective construction of two complex bacterial oligosaccharide fragments are described. These fragments contain mannuronic acid residues connected through a beta-linkage, which is amongst the most challenging linkages to construct synthetically. In the second part, the use of mannuronic acid building blocks in the automated synthesis of alginates using solid-phase chemistry is presented. Using a second-generation carbohydrate synthesizer, alginate fragments up to 12 residues were assembled with high stereoselectivity. Using the same automated set-up, fragments of hyaluronic acid of up to 15 residues were synthesized. In the third part, 2-deoxy-2-fluoroglucosides are investigated as activity-based probes for glucocerebrosidase, a retaining beta-glucosidase enzyme.NWO, TI PharmaUBL - phd migration 201