A Large TPC Prototype with MPGD Readout: Status and Plans

The use of a TPC in future collider experiments needs significant research and development. Within the EUDET program an infrastructure has been designed and built to allow the efficient testing of TPC prototypes under realistic conditions. The infrastructure consists of a test beam facility, located at DESY Hamburg, and a multi-purpose TPC field cage.Comment: Conference LCES 2008, Chicag

A critical approach to some new ideas about the Dutch flood risk system

Decisions on measures to improve a flood risk system are in part supported by general ideas about how the system works and should work. After the completion of the Dutch Delta Works around 1990, such new ideas regarding flood risk emerged. Some of these may be appealing at first, but appear debatable after a closer look. In this paper, fourteen such debatable ideas, familiar to most Dutch water professionals, are formulated and criticised, in order to find out what can be learned from them. The most important Dutch national flood risk policy documents since 1990 are reviewed for quotes that illustrate these ideas, complemented by scientific papers and other documents. These quotes present different expressions of these ideas, and their number can suggest whether they are broadly shared or marginal. In twelve of the twenty most important government documents, 47 quotes were found; in 26 documents of other types, another 39. Eleven quotes describe the idea that ‘water should not be our enemy, but our friend’. Fifteen quotes were based on the idea that flood protection entraps us in a dangerous ‘spiral of risk’, which can be stopped, 44 quotes are related to the idea that flood risk reducing measures should be ‘natural’ or ‘move with nature’. The remaining quotes illustrate other debatable ideas, such as ‘water should lead spatial planning’ and ‘rivers should not be squeezed into a corset’. The frequency of such quotes suggests that ideas about ‘water as a friend’, the ‘spiral of risk’ and ‘moving with nature’ have not been marginal. It is however difficult to determine how influential they have been in decision-making, since general ideas are not the only factors leading to decisions. The general critique to the three ideas is that they present preferred measures as generally logical conclusions without a systematic comparison of alternatives for particular situations. Behind the new ideas lies increasing societal interest for objectives like an attractive water landscape (water as a friend), reducing our dependence on technology (spiral of risk) and nature conservation and development (moving with nature). This analysis further suggests a couple of final remarks, which are hard to prove and are open for discussion

Multimodality imaging in prevention of coronary artery disease:creating synergy between tests and therapies

In the Netherlands, 34.000 individuals suffer from a heart attack and 36.000 individuals die from cardiovascular disease yearly. A heart attack is caused by calcification of the coronary arteries of the heart, also known as coronary artery calcification. Currently, no national screenings program exists for coronary artery calcification, unlike for other common diseases such as cancer. Prevention of coronary artery calcification, that can cause heart attack or sudden cardiac death, is currently arranged in a way that individuals need to visit the general practitioner themselves in the Netherlands to seek preventive care. The general practitioner will then make a risk estimation based on the presence of traditional risk factors for coronary artery calcification, such as high blood pressure and smoking. Based on this risk estimation, early therapy with support in lifestyle adjustments, such as quitting smoking, and in certain cases also prescription of cholesterol- and blood pressure-lowering medication is initiated. Risk estimation based on clinical risk prediction doesn’t provide a direct image of what is happening in the coronary arteries. This risk prediction is therefore often inaccurate, leading to over- and undertreatment. By a combination of imaging techniques of the heart, such as CT- and MRI-scans, coronary artery calcification can be early detected, which allows for treatment adapted to the actual state of disease. The use of imaging techniques of the heart to predict the risk of heart attack and sudden cardiac death in screening, in which each individual who would like to can undergo a scan, might allow a unique chance to early detect and effectively treat individuals with a strongly increased risk, before they suffer from severe damage to the heart. In this thesis, a first step is being made by investigating whether several stages of subclinical coronary artery calcification can be effectively detected by a combination of imaging techniques of the heart, and whether this leads to improved prevention. Also, this thesis tries to seek for methods to improve the selection of those who potentially benefit from early detection, to reduce costs and increase efficiency

Regulation of sulfate metabolism in C4 plants:A whole plant perspective

Plants usually acquire sulfur, which is an essential macronutrient for the proper taste, smell and color of crop products, as sulfate. The availability of sulfate is, however, often suboptimal and hence sulfur availability limits crop yield and quality across the world. To improve sulfur fertilizer levels, a detailed understanding of the regulation of sulfate uptake and reduction is crucial. It is particularly important to appreciate this regulation in plants that employ C4 photosynthesis, since C4 crops may be increasingly cultivated. Research has, however, been focused on plants that employ C3 photosynthesis. Findings cannot simply be generalized from C3 to C4 plants, for these plants differ considerably in their physiology. Thus, my dissertation addresses the regulation of sulfate uptake and reduction in C4 plants. I first emphasize the need for plant sulfur research by showing that sulfate deprivation is associated with the production of aberrant floral displays. Subsequently, I analyze the regulation of sulfate uptake and reduction at the whole plant level by exposing plants to atmospheric hydrogen sulfide (H2S). I observed that plants differ considerably in their response to gaseous H2S, though C3 and C4 plants did not respond distinctively to atmospheric H2S. Therefore, I conclude that the whole plant regulation of sulfate uptake and reduction profoundly differs among plants, but that C3 and C4 photosynthesis are not associated with markedly different types of this regulation. To understand the variation in whole plant sulfate metabolism, I recommend to conduct physiological experiments (instead of molecular biological experiments). I argue that regulatory mechanisms at the molecular level have no direct significance in determining the whole plant regulation of sulfate uptake and reduction

On the capacity and normalisation of ISI channels

[Abstract]: We investigate the capacity of various ISI channels with additive white Gaussian noise. Previous papers showed a minimum Eb/N0 of −4.6 dB, 3 dB below the capacity of a flat channel, is obtained using the water-pouring capacity formulas for the 1 + D channel. However, these papers did not take into account that the channel power gain can be greater than unity when water-pouring is used. We present a generic power normalization method of the channel frequency response, namely peak bandwidth normalisation, to facilitate the fair capacity comparison of various ISI channels. Three types of ISI channel, i.e., adder channels, RC channels and magnetic recording channels, are examined. By using our channel power gain normalization, the capacity curves of these ISI channels are shown