Dreijen Regeneration Study: Professional Academy 2007

This year the students of the “Professional Academy”, a combined theory and design class in landscape architecture, elaborated on a vision on the campus “de Dreijen” in Wageningen. This campus will be left by the university within the coming decade, university functions mainly moving towards the new campus “de Born” in the North of the city. Their “research by design” study brought about very different visions, but they all reflected the main theories learnt about urban sustainability and ecolog

Sudden Collapse of a Granular Cluster

Single clusters in a vibro-fluidized granular gas in N connected compartments become unstable at strong shaking. They are experimentally shown to collapse very abruptly. The observed cluster lifetime (as a function of the driving intensity) is analytically calculated within a flux model, making use of the self-similarity of the process. After collapse, the cluster diffuses out into the uniform distribution in a self-similar way, with an anomalous diffusion exponent 1/3.Comment: 4 pages, 4 figures. Figure quality has been reduced in order to decrease file-siz

Predictors of outcomes in diabetic foot osteomyelitis treated initially with conservative (nonsurgical) medical management: A retrospective study

The optimal way to manage diabetic foot osteomyelitis remains uncertain, with debate in the literature as to whether it should be managed conservatively (ie, nonsurgically) or surgically. We aimed to identify clinical variables that influence outcomes of nonsurgical management in diabetic foot osteomyelitis. We conducted a retrospective study of consecutive patients with diabetes presenting to a tertiary center between 2007 and 2011 with foot osteomyelitis initially treated with nonsurgical management. Remission was defined as wound healing with no clinical or radiological signs of osteomyelitis at the initial or contiguous sites 12 months after clinical and/or radiological resolution. Nine demographic and clinical variables including osteomyelitis site and presence of foot pulses were analyzed. We identified 100 cases, of which 85 fulfilled the criteria for analysis. After a 12-month follow-up period, 54 (63.5%) had achieved remission with nonsurgical management alone with a median (interquartile range) duration of antibiotic treatment of 10.8 (10.1) weeks. Of these, 14 (26%) were admitted for intravenous antibiotics. The absence of pedal pulses in the affected foot (n = 34) was associated with a significantly longer duration of antibiotic therapy to achieve remission, 8.7 (7.1) versus 15.9 (13.3) weeks (P = .003). Osteomyelitis affecting the metatarsal was more likely to be amputated than other sites of the foot (P = .016). In line with previous data, we have shown that almost two thirds of patients presenting with osteomyelitis healed without undergoing surgical bone resection

Effects of light and soil flooding on the growth and photosynthesis of ramin (Gonystylus bancanus) seedlings in Malaysia

We studied the ecophysiology of ramin (Gonystylus bancanus) seedlings in an experimental set up at the Forest Research Centre in Kuching, Sarawak, Malaysia. Ramin seedlings were grown on flooded and drained peat soil under 100, 76, 46 and 23% sunlight, thus simulating effects of different light conditions (canopy gap size) and drainage that occur in natural ramin populations. Seedling growth was highest in partial sunlight (76%) and reduced with reducing light levels. Aboveground productivity and fine root development were significantly higher in seedlings grown on flooded soil compared with those on drained soil. In contrast, investment in coarse root biomass was significantly higher in seedlings grown on drained soil. It appeared that the aboveground growth benefits in flooded conditions were the result of more advantageous conditions for allocation of carbon to leaves, thus enhancing overall relative growth rates through higher light interception rates despite lower photosynthetic capacity. The results of this experiment suggested that drainage of peat swamp forests would seriously hamper natural regeneration of ramin by limiting the growth of seedlings. It is also suggested that selective logging operations which produce medium-size canopy gaps improve ramin regeneration in hydrologically undisturbed mixed swamp forest

Bifurcations of the Hamiltonian fourfold 1:1 resonance with toroidal symmetry

This paper deals with the analysis of Hamiltonian Hopf as well as saddle-centre bifurcations in 4-DOF systems defined by perturbed isotropic oscillators (1:1:1:1 resonance), in the presence of two quadratic symmetries ¿ and L1. When we nor- malize the system with respect to the quadratic part of the energy and carry out a reduction with respect to a 3-torus group we end up with a 1-DOF system with several parameters on the thrice reduced phase space. Then, we focus our analysis on the evolution of relative equilibria around singular points of this reduced phase space. In particular, dealing with the Hamiltonian Hopf bifurcation the `geometric approach' is used, following the steps set up by one of the authors in the context of 3-DOF systems. In order to see the interplay between integrals and physical param- eters in the analysis of bifurcations, we consider as perturbation a one-parameter family, which in particular includes one of the classical Stark-Zeeman models (par- allel case) in 3 dimension

Hamiltonian four fold 1:1 resonance with two rotational symmetries

In this communication we deal with the analysis of Hamiltonian Hopf bifurcations in 4-DOF systems defined by perturbed isotropic oscillators (1-1-1-1 resonance), in the presence of two quadratic symmetries I 1 and I 2. As a perturbation we consider a polynomial function with a parameter. After normalization, the truncated normal form gives rise to an integrable system which is analyzed using reduction to a one degree of freedom system. The Hamiltonian Hopf bifurcations are found using the ‘geometric method’ set up by one of the authors

De functie van het Borgstellingsfonds voor de Landbouw: Een quickscan naar de functie in de huidige vorm en marktsituatie

By means of a quickscan, this research describes the role of the Agricultural Loan Guarantee Fund (BF) instrument for agricultural entrepreneurs in its current form and within the current market situation. In this, account was taken of the general trends in the sectors that are important for the BF, the current BF decree, indications providing insight into the importance of the instrument, the financing policy of banks and the role of the BF, and the idea of possibly using the BF to stimulate innovation. The description is based on data from LEI's Farm Accountancy Data Network, data from the Agricultural Loan Guarantee Fund foundation, and interviews with experts from banking practice. Dit onderzoek beschrijft in een quickscan de functie van het instrument Borgstellingsfonds voor de Landbouw (BF) in de huidige vorm en marktsituatie voor de agrarische ondernemers. Hierbij is rekening gehouden met de algemene trends in de voor BF belangrijke sectoren, het huidige besluit BF, indicatoren die inzicht geven in het belang van het instrument, het financieringsbeleid van banken en de rol van BF en het idee om BF mogelijk te gebruiken voor het stimuleren van innovaties. De beschrijving is gebaseerd op gegevens uit het Bedrijven-Informatienet van het LEI, gegevens van de Stichting Borgstellingsfonds voor de Landbouw en interviews met deskundigen uit de bancaire praktijk.Agricultural Finance,

Bifurcation Diagram for Compartmentalized Granular Gases

The bifurcation diagram for a vibro-fluidized granular gas in N connected compartments is constructed and discussed. At vigorous driving, the uniform distribution (in which the gas is equi-partitioned over the compartments) is stable. But when the driving intensity is decreased this uniform distribution becomes unstable and gives way to a clustered state. For the simplest case, N=2, this transition takes place via a pitchfork bifurcation but for all N>2 the transition involves saddle-node bifurcations. The associated hysteresis becomes more and more pronounced for growing N. In the bifurcation diagram, apart from the uniform and the one-peaked distributions, also a number of multi-peaked solutions occur. These are transient states. Their physical relevance is discussed in the context of a stability analysis.Comment: Phys. Rev. E, in press. Figure quality has been reduced in order to decrease file-siz