Mean and Bold?

The Dutch drinking water sector experienced two drastic changes over the last 10 years. Firstly, in 1997, the sector association started with a voluntary benchmarking aimed to increase the efficiency and effectiveness of the sector. Secondly, merger activity arose. This paper develops a tailored nonparametric model to dissect and distinguish the effects on efficiency of these two evolutions. In particular, we adapt Free Disposal Hull (FDH) to estimate robust and conditional non-oriented efficiency estimates. Parametric COLS (Fourier) tests show the robustness of the model with respect to the specification and its variables. We classify the merger economies into scale economies and increased incentives to fight inefficiencies. Although we detect a significant efficiency enhancing effect of benchmarking, we find insignificant merger economies due to the absence of scale economies and the absence of increased incentives to fight inefficiencies

Design and development of spherical array antennas

Array antennas have been developed that can achieve electronic beamsteering over wide angles. With circular array antennas, a radiation pattern can be steered over 360 azimuthal degrees without pattern deterioration. Some applications may require an omnidirectional beamsteering capability in azimuth as well as in elevation, with antenna characteristics that are independent from the direction of the beam. To achieve this without mechanical actuators requires an antenna that is homeomorphic to the sphere. Spherical array antennas are the 3-dimensional equivalent of circular array antennas and offer a full omnidirectional beamsteering coverage. Using standard Fourier techniques, the analysis and synthesis of a circular array can be simplified. The technique is known as phase mode theory and allows a number of signal process ing techniques such as electronic direction finding to be demonstrated. The symmetry found in spherical array antennas can equally be exploited using spherical harmonics as a basis for Fourier analysis. Spherical array antennas have not enjoyed the same attention as circular arrays, nor have they been the subject, with the exception of SONAR arrays, of a profound study that is equivalent to phase mode theory. This thesis aims to put spherical arrays on the same foot as circular arrays, by using spherical modes to build the theoretical framework for the analysis, synthesis and design of spherical array antennas. Using a technique for conformal array antennas, an holistic model for the spherical array antenna is derived to analyse the radiation from complex spherical arrays, based on analytically obtained expressions. Mutual coupling effects are quantified and included in the calculations. Also some typical antenna characteristics and design considerations are reviewed in the light of modal theory, in order to obtain design formula's for the spherical array antenna. Apart from the electromagnetic approach, attention is given to the processing of the signals. Modal theory lends itself for the development of smart antennas, and the foundations to do that with spherical arrays are laid down. A particular problem arises when one wants to distribute the array elements evenly over the spherical surface. This topic is also given an in-depth treatment, for distributions of single elements as well as for more advanced subarraying techniques. To back up the findings from theory and simulation, as well as to demonstrate the unique capabilities of the spherical array antenna, a prototype array has been designed and partially constructed. The design and development of this antenna is covered to the point where a partially completed spherical array could be measured. Results of these measurements are encouraging and sufficient to show the potential of spherical array antennas. Finally, suggestions are given for future experiments and how to further advance spherical array technology

Superparamagnetic relaxation in Cu_{x}Fe_{3-x}O_{4} (x=0.5 and x=1) nanoparticles

The scope of this article is to report very detailed results of the measurements of magnetic relaxation phenomena in the new Cu$_{0.5}$Fe$_{2.5}$O$_{4}$ nanoparticles and known CuFe$_{2}$O$_{4}$ nanoparticles. The size of synthesized particles is (6.5$\pm$1.5)nm. Both samples show the superparamagnetic behaviour, with the well-defined phenomena of blocking of magnetic moment. This includes the splitting of zero-field-cooled and field-cooled magnetic moment curves, dynamical hysteresis, slow quasi-logarithmic relaxation of magnetic moment below blocking temperature. The scaling of the magnetic moment relaxation data at different temperatures confirms the applicability of the simple thermal relaxation model. The two copper-ferrites with similar structures show significantly different magnetic anisotropy density and other magnetic properties. Investigated systems exhibit the consistency of all obtained results.Comment: 18 pages, 8 figure

User-centered development and testing of a monitoring system that provides feedback regarding physical functioning to elderly people

Purpose: To involve elderly people during the development of a mobile interface of a monitoring system that provides feedback to them regarding changes in physical functioning and to test the system in a pilot study. Methods and participants: The iterative user-centered development process consisted of the following phases: (1) selection of user representatives; (2) analysis of users and their context; (3) identification of user requirements; (4) development of the interface; and (5) evaluation of the interface in the lab. Subsequently, the monitoring and feedback system was tested in a pilot study by five patients who were recruited via a geriatric outpatient clinic. Participants used a bathroom scale to monitor weight and balance, and a mobile phone to monitor physical activity on a daily basis for six weeks. Personalized feedback was provided via the interface of the mobile phone. Usability was evaluated on a scale from 1 to 7 using a modified version of the Post-Study System Usability Questionnaire (PSSUQ); higher scores indicated better usability. Interviews were conducted to gain insight into the experiences of the participants with the system. Results: The developed interface uses colors, emoticons, and written and/or spoken text messages to provide daily feedback regarding (changes in) weight, balance, and physical activity. The participants rated the usability of the monitoring and feedback system with a mean score of 5.2 (standard deviation 0.90) on the modified PSSUQ. The interviews revealed that most participants liked using the system and appreciated that it signaled changes in their physical functioning. However, usability was negatively influenced by a few technical errors. Conclusion: Involvement of elderly users during the development process resulted in an interface with good usability. However, the technical functioning of the monitoring system needs to be optimized before it can be used to support elderly people in their self-management

Diffractive shear interferometry for extreme ultraviolet high-resolution lensless imaging

We demonstrate a novel imaging approach and associated reconstruction algorithm for far-field coherent diffractive imaging, based on the measurement of a pair of laterally sheared diffraction patterns. The differential phase profile retrieved from such a measurement leads to improved reconstruction accuracy, increased robustness against noise, and faster convergence compared to traditional coherent diffractive imaging methods. We measure laterally sheared diffraction patterns using Fourier-transform spectroscopy with two phase-locked pulse pairs from a high harmonic source. Using this approach, we demonstrate spectrally resolved imaging at extreme ultraviolet wavelengths between 28 and 35 nm

From vocational training to education: the development of a no-frontiers education policy for Europe?

This article focuses on developments towards an EU educational policy. Education was not included as one of the Community competencies in the Treaty of Rome. The first half of the article analyses the way that the European Court of Justice and the Commission of the European Communities between them managed to develop a series of substantial Community programmes out of Article 128 on vocational training. The second half of the article discusses educational developments in the community following the Treaty on European Union and the Treaty of Amsterdam. Whilst the legal competence of the community now includes education, the author's argument is that the inclusion of an educational competence will not result in further developments to mirror those in the years before the Treaty on Europe</p

In-gas-cell laser ionization spectroscopy in the vicinity of 100Sn: Magnetic moments and mean-square charge radii of N=50-54 Ag

In-gas-cell laser ionization spectroscopy studies on the neutron deficient 97-101Ag isotopes have been performed with the LISOL setup. Magnetic dipole moments and mean-square charge radii have been determined for the first time with the exception of 101Ag, which was found in good agreement with previous experimental values. The reported results allow tentatively assigning the spin of 97,99Ag to 9/2 and confirming the presence of an isomeric state in these two isotopes, whose collapsed hyperfine structure suggests a spin of 1/2 . The effect of the N=50 shell closure is not only manifested in the magnetic moments but also in the evolution of the mean-square charge radii of the isotopes investigated, in accordance with the spherical droplet model predictions