Counting spanning trees on fractal graphs and their asymptotic complexity

Using the method of spectral decimation and a modified version of Kirchhoff's Matrix-Tree Theorem, a closed form solution to the number of spanning trees on approximating graphs to a fully symmetric self-similar structure on a finitely ramified fractal is given in Theorem \ref{thm:maintheoremfull}. We show how spectral decimation implies the existence of the asymptotic complexity constant and obtain some bounds for it. Examples calculated include the Sierpinski Gasket, a non post critically finite analog of the Sierpinski Gasket, the Diamond fractal, and the Hexagasket. For each example, the asymptotic complexity constant is found.Comment: 26 pages. arXiv admin note: substantial text overlap with arXiv:1211.734

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Rectorale oratie Vrije Universiteit 191

Hesse Pencils and 3-Torsion Structures

This paper intends to focus on the universal property of this Hesse pencil and of its twists. The main goal is to do this as explicit and elementary as possible, and moreover to do it in such a way that it works in every characteristic different from three

Stakeholder engagement in water governance as social learning: lessons from practice

The OECD Principles on Water Governance set out various requirements for stakeholder engagement. Coupled with conceptualizations of social learning, this article asks how we define and enact stakeholder engagement and explores the actual practice of engagement of stakeholders in three fields of water governance. The results suggest that a key consideration is the purpose of the stakeholder engagement, requiring consideration of its ethics, process, roles and expected outcomes. While facilitators cannot be held accountable if stakeholder engagement ‘fails’ in terms of social learning, they are responsible for ensuring that the enabling conditions for social learning are met

PlantyOrganic; Voortgang 2013

2013 was het tweede jaar waarin de systeemontwikkeling "PlantyOrganic" in praktijk is gebracht. Op de zes percelen zijn de gewassen geteeld die voorzien waren en zijn metingen verricht aan bodem en gewas. Met uitzondering van de aardappelen hadden in 2013 alle gewassen de voorvrucht die in het ontwerp was voorzien. De gebruikte meststoffen waren geheel afkomstig vanuit het eigen systeem, zoals in het ontwerp was voorzien. De totaal gegeven hoeveelheden stikstof waren ca. 45 % hoger dan waar in het ontwerp van uit is gegaan. De bodemstikstof is getoetst met metingen die in het stikstofmodel NDICEA zijn ingevoerd. De match tussen metingen en berekeningen is voldoende tot goed, met een enkele uitzondering. De gewassen groeiden goed, met hoge opbrengsten in de peen en de haver, en een tegenvallende opbrengsten in de tarwe. De tarwe heef last gehand van stikstofgebrek, waarvoor we nog geen goede verklaring hebben. In de bloemkool heeft stikstofgebrek in de laatste groeifase een negatieve invloed gehad op de kwaliteit, waardoor het niet afgezet kon worden. Alle percelen zijn groen de winter in gegaan. Tot nu toe is geen onderzoek aan beschikbaarheid van fosfaat en kali gedaan. Door de nul-aanvoer van mineralen van buiten het bedrijf is de balans negatief. Op termijn kan deze kringloop gesloten worden door regionale terugvoer van fosfaat en kali met bv. GFT compost of rioolslib. Planty Organic kan een zeer geschikte proeflocatie worden voor onderzoek naar de mobilisatie van fosfaat (en kali) onder omstandigheden van een lage aanvoer en/of een lage bodemchemisch gemeten beschikbaarheid

PlantyOrganic: Results 2013

2013 was the second year of the "PlantyOrganic" system development in practice. The six-year rotation is laid out and measurements took place at soil and crop. With the exception of the potatoes in 2013 all crops had the pre-crop as foreseen in the design. The fertilizers used were completely produced in the own system, as foreseen in the system design. The amounts of nitrogen applied were about 45 % higher than in the design. Soil nitrogen is measured and used as input in the nitrogen model NDICEA. There was a sufficient match between measured and calculated level of soil mineral nitrogen. The crops performed well, with a high yield in carrots and oats, and a disappointing yield in wheat. In wheat nitrogen was limiting for the yield, we do not yet have a satisfactory explanation. In cauliflower a lack of nitrogen ijn the last phase of the growth had a negative effect on the quality and the crop could not be sold. All plots went green into the winter. Until now no research has been done on the availability of phosphate and potassium. Because there is no supply of these minerals from outside the system, the balance is negative. In time the circle could be closed by means of regional re-use of minerals, for example by the application of household waste compost. PlantyOrganic can become a very good research location for research on the mobilisation of phosphate (and potassium) in circumstances of low supply and/or low chemically analysed availability

Effectiveness of multifaceted implementation strategies for the implementation of back and neck pain guidelines in health care: a systematic review

Background: For the optimal use of clinical guidelines in daily practice, mere distribution of guidelines and materials is not enough, and active implementation is needed. This review investigated the effectiveness of multifaceted implementation strategies compared to minimal, single, or no implementation strategy for the implementation of non-specific low back and/or neck pain guidelines in health care. Methods: The following electronic databases were searched from inception to June 1, 2015: MEDLINE, Embase, PsycInfo, the Cochrane Library, and CINAHL. The search strategy was restricted to low back pain, neck pain, and implementation research. Studies were included if their design was a randomized controlled trial, reporting on patients (age ≥18years) with non-specific low back pain or neck pain (with or without radiating pain). Trials were eligible if they reported patient outcomes, measures of healthcare professional behaviour, and/or outcomes on healthcare level. The primary outcome was professional behaviour. Guidelines that were evaluated in the studies had to be implemented in a healthcare setting. No language restrictions were applied, and studies had to be published full-text in peer-reviewed journals, thus excluding abstract only publications, conference abstracts, and dissertation articles. Two researchers independently screened titles and abstract, extracted data from included studies, and performed risk of bias assessments. Results: After removal of duplicates, the search resulted in 4750 abstracts to be screened. Of 43 full-text articles assessed for eligibility, 12 were included in this review, reporting on 9 individual studies, and separate cost-effectiveness analyses of 3 included studies. Implementation strategies varied between studies. Meta-analyses did not reveal any differences in effect between multifaceted strategies and controls. Conclusion: This review showed that multifaceted strategies for the implementation of neck and/or back pain guidelines in health care do not significantly improve professional behaviour outcomes. No effects on patient outcomes or cost of care could be found. More research is necessary to determine whether multifaceted implementation strategies are conducted as planned and whether these strategies are effective in changing professional behaviour and thereby clinical practice

Influences of hospital information systems, indicator data collection and computation on reported Dutch hospital performance indicator scores

Background: For health care performance indicators (PIs) to be reliable, data underlying the PIs are required to be complete, accurate, consistent and reproducible. Given the lack of regulation of the data-systems used in the Netherlands, and the self-report based indicator scores, one would expect heterogeneity with respect to the data collection and the ways indicators are computed. This might affect the reliability and plausibility of the nationally reported scores. Methods. We aimed to investigate the extent to which local hospital data collection and indicator computation strategies differ and how this affects the plausibility of self-reported indicator scores, using survey results of 42 hospitals and data of the Dutch national quality database. Results: The data collection and indicator computation strategies of the hospitals were substantially heterogenic. Moreover, the Hip and Knee replacement PI scores can be regarded as largely implausible, which was, to a great extent, related to a limited (computerized) data registry. In contrast, Breast Cancer PI scores were more plausible, despite the incomplete data registry and limited data access. This might be explained by the role of the regional cancer centers that collect most of the indicator data for the national cancer registry, in a standardized manner. Hospitals can use cancer registry indicator scores to report to the government, instead of their own locally collected indicator scores. Conclusions: Indicator developers, users and the scientific field need to focus more on the underlying (heterogenic) ways of data collection and conditional data infrastructures. Countries that have a liberal software market and are aiming to implement a self-report based performance indicator system to obtain health care transparency, should secure the accuracy and precision of the heath care data from which the PIs are calculated. Moreover, ongoing research and development of PIs and profound insight in the clinical practice of data registration is warranted