Sustainable flower bulb production: prototyping integrated flower bulb production systems on sandy soils in The Netherlands

Flower bulb production in The Netherlands is economically successful. However, production methods rely heavily on external inputs, causing contamination of surface and ground water. The use of pesticides has been estimated 100 kg active ingredient (a.i.) per ha in 1994. In the same year the annual use of nitrogen and phosphate was 310 and 130 kg per ha respectively. Over the last decade the Dutch government established targets for the input and emission of pesticides and (in)organic fertilizers, energy use and volume of production related waste. Prototype flower bulb farming systems, with regard to these objectives, were developed, tested and improved on three experimental farms. This article concentrates on the results of two experimental farms on sandy soils in the west of The Netherlands in the period 1991-1997: ‘De Noord’ at St. Maartensbrug and ‘De Zuid’ at Hillegom. At both experimental farms the use of pesticides was reduced with at least 75% compared to the reference year of 1987-1988. Considerable reduction in the use of soil fumigants and fungicides was realised, but not of herbicides and insecticides. The use of nitrogen and phosphate decreased to approximately 215 kg and 55 kg per ha respectively. The integrated prototypes of experimental farm ‘De Zuid’ were economically competitive with flowerbulb farms in the same region. Integrated farming prototypes of ‘De Noord’ were less profitable due to suboptimal soil conditions, over-ambitious research targets and i nexperienced management. As a spin-off of this farming system research, 24 flower bulb growers are converting to integrated flowerbulb growing on their farms. They are supported by research and extension worker

ECONOMIES OF SIZE AMONG MUNICIPAL WATER AUTHORITIES IN PENNSYLVANIA

Resource /Energy Economics and Policy,

Structural and biochemical characterization of ctTel1, an ATM kinase ortholog from Chaetomium thermophilum

Ataxia-Telangiectasia Mutated (ATM) is an apical signalling kinase that responds to DNA double strand breaks (DSBs). DSBs are the most dangerous form of DNA damage. Therefore cells have evolved multiple pathways to repair such lesions and signal the damage to the cell to organise the DNA damage response (DDR). DSBs are sensed by the Mre11-Rad50-Nbs1 (MRN) complex, which initiates repair via homologous recombination (HR). At the beginning of this process, MRN activates the ATM kinase, which phosphorylates hundreds of substrates, including other DNA repair factors and kinases to orchestrate a cell-wide DNA damage response. ATM belongs to the family of PI3-kinase like kinases (PIKKs). It has a very large HEAT-repeat domain, which plays a role in interacting with other proteins, and a highly conserved kinase domain, showing more homology to PI3-lipid kinases than protein kinases. ATM is normally present in the nucleus as an autoinhibited dimer, but rapidly becomes active upon DNA damage. As a part of its activation mechanism ATM is postulated to monomerise and become autophosphorylated. In order to understand the molecular mechanism of ATM activation better, the aim of this work was to solve the structure of ctTel1, a fungal ATM ortholog from the mould Chaetomium thermophilum, using cryo-electron microscopy (cryo-EM). Due the large size of the protein (650 kDa as a dimer) recombinant expression was not possible. Therefore ctTel1 was puried from endogenous sources. The other aim was to characterise its interaction with MRN and DNA, for which a truncated ctTel1 construct was used which could be obtained in large quantities. Using the truncated construct, the interactions between ATM and Nbs1, and the MRN complex were characterised using pull-downs, analytical gel filtration and fluorescence anisotropy, showing that it forms a stable complex. Furthermore we found that truncated ctTel1 has DNA binding properties, preferring blunt-ended double stranded DNA and displaying a length-dependency. Using cryo-EM we determined the first complete and the highest resolution structure of any ATM kinase to date, with the kinase domain at 2.8 A and an overall structure including the HEAT repeat domain at 3.7 A. This allowed for the building of a complete atomic model, except for a number of flexible loops. The structure reveals a hydrophobic dimer interface, suggesting monomerisation is unlikely to be an aspect of the activation mechanism. In the active site of the kinase the loops required for catalysis are structured, coordinating ATPgS and a Mg2+ ion. This suggests that ATM is in a catalytic proficient state. However, access to the active site is physically blocked by the PIKK regulatory domain (PRD) a regulatory helix. The PRD thus functions as a pseudosubstrate, suggesting that part of the activation mechanism entails its removal in response to allosteric binding of activators. Cancer mutations and ataxia-telangiectasia (A-T) mutations were mapped onto the structure, revealing the elements which are important for the activation. Taken together, the ctTel1 structure reveals the autoinhibitory circuitry and provides the first step towards understanding the activation mechanism of this important kinase

A Functional Perspective on probiotic Interventions in the Small Intestine:Dynamics and Emergent Properties of the Microbial Community

Our intestines are inhabited by bacteria, which form a network and keep us healthy. Simultaneously, too many bad bacteria can affect our health negatively. Luckily, many types of treatments targeting our gut bacteria are being developed, such as probiotics. However, most probiotics target the large intestine.In this thesis, we studied the effect of probiotics on the small intestinal bacteria. Since the bacterial community in the small intestine is not as easily accessible, we used two ways to circumvent this inaccessible organ. First we used content obtained from stoma bags of people without a large intestine. Secondly, we made a mock small intestinal community by growing three bacteria together. In both experiments we measured the number of bacteria, the pH and metabolites, which are compounds that can be used or produced by the bacteria. In both experiments, we observed an altered production of metabolites and growth of specific bacteria. Secondly, the probiotic bacteria mad a more connected network of metabolites, which indicates a higher resistance to perturbations of bad bacteria. When we compared the functionality, which are the metabolites each bacteria can produce, of the probiotic bacteria, and compared it to the bacteria in the community, we found that the probiotic bacteria with a different functionality from the community increased the usage of metabolites. Thus it is important to know the functionality of someone’s gut bacteria and find a probiotic with a functionality that is complementary. To do this, we describe how flux balance analysis, a simulation method, can be used to personalize probiotic treatment

Samen appels plukken in het park

Vijftien steden, verenigd in het netwerk stadslandbouw, zoeken naar wegen om stadslandbouw te stimuleren. Nu lopen nog veel initiatieven vast op gebrek aan beleid en tegenwerkende regelgeving

Self-management in rehabilitation practice:On the design and implementation of a serious theory-based analogue problem-solving game called ‘Think Along?’.

This thesis describes the place of the concept of self-management within rehabilitation practice at UMCG Beatrixoord in Haren and the development of a serious game called "Denk je Mee?" ("Think Along?"). Better self-management skills in patients are expected to improve their transfer from the rehabilitation centre to their homes. A literature review by means of a comparative language analysis revealed that besides similarities, there are also differences between the concepts self-management and rehabilitation. Extensive qualitative research (document analysis, observations, and interviews) provided insights into the extent to which self-management is interwoven into daily rehabilitation practice. These research findings were then used to develop a serious game, "Think Along?". It was designed as a problem-solving game since problem solving is considered as one of the important self-management skills. While playing the serious game, players are given the opportunity to experiment with problems they will very likely encounter in their home situation. To give the serious game a place in existing healthcare logistics, it was implemented in a circular way through seven steps. Whenever it became clear during a step that an adaptation was needed, this was done always in consultation with the practitioners. This way of working has led to "Think Along?" being an integral part of care logistics in both the pulmonary and oncology departments of rehabilitation centre UMCG Beatrixoord until this day