1,844 research outputs found
Measuring and Explaining the Productive Efficiency of Tax Offices. a Non-Parametric Best Practice Frontier Approach
In this paper we mimic an engineeriilg approach to the "production" of tax offices. Essentially one dominant physical input (labour) is converted into heterogeneous non-monetary outputs such as theNumber of audited returns with a different degree of complexity. Productive efficiency is evaluated against a best practice frontier using the non-parametric Free Disposal (FDH) method and Data Envelopment Analysis (DEA). We first calculate efficiency measures for 289 regional tax offices, responsible for the personal income tax in Belgium. Next we explain the differences in efficiency scores in terms of characteristics related to managerial skills/culture and organizational structures.
The Effect of Psychiatric Rehabilitation on the Activity and Participation Level of Clients with Long-Term Psychiatric Disabilities
During the last decades of the 20th century, many psychiatric hospitals changed the living environments of their clients with long-term psychiatric disabilities.
We investigated the effect of this environmental psychiatric rehabilitation and normalization process on the activity and participation level of such clients residing in one Dutch psychiatric hospital. The seven years of panel research demonstrated that more normal living environments have a positive effect on clients’ activity and participation level. This is controlled for the fact that younger clients, and clients with a relative high activity and participation level were selected for these normal living environments.
“A wind of change” in recreational fisheries? Recreational fishermen and wind farms: current use and perception
Offshore wind farms create opportunities for recreational fishermen in Belgium, since the presence of hard substrates and the closure for trawling create a favorable habitat for fish. After the construction in 2008, a concentration of anglers was observed in the vicinity of the first wind farm during monitoring. In the following years, however, the interest of anglers for the wind farms seemed to disappear. To elucidate the evolution in the relation between recreational angling intensity and wind farms, this study aimed to assess how Belgian recreational fishermen perceive wind farms, how often they visit them and why, and which fish species they (expect to) catch. Data were derived from the annual DCF survey for recreational fishermen. Less than 2% of the sea anglers reported to go fishing in the larger wind farm area, even when 30 to 40 percent of the respondents either expected more fish, bigger fish or other fish species. The main reasons to stay away from wind farms is because entering the wind farms themselves is not allowed, because the distance to the wind farms is relatively large, because charter vessels do not offer fish trips to wind farms, and because wind farms are protection zones and nursery areas for fish. 40% of the respondents would consider fishing inside wind farms if it were allowed, mainly because they expect more or other fish. This is a clear indication that the enforcement of wind farm closure for fisheries and shipping is vital when aiming at the creation and/or restoration of nursing grounds in the area. However, the large distance to the wind farms will probably continue to limit fishing pressure, even if wind farms would (partly) be opened for recreational fisheries
The influence of the secondary electrons induced by energetic electrons impacting the Cassini Langmuir probe at Saturn
The Cassini Langmuir Probe (LP) onboard the Radio and Plasma Wave Science experiment has provided much information about the Saturnian cold plasma environment since the Saturn Orbit Insertion in 2004. A recent analysis revealed that the LP is also sensitive to the energetic electrons (250–450 eV) for negative potentials. These electrons impact the surface of the probe and generate a current of secondary electrons, inducing an energetic contribution to the DC level of the current-voltage (I-V) curve measured by the LP. In this paper, we further investigated this influence of the energetic electrons and (1) showed how the secondary electrons impact not only the DC level but also the slope of the (I-V) curve with unexpected positive values of the slope, (2) explained how the slope of the (I-V) curve can be used to identify where the influence of the energetic electrons is strong, (3) showed that this influence may be interpreted in terms of the critical and anticritical temperatures concept detailed by Lai and Tautz (2008), thus providing the first observational evidence for the existence of the anticritical temperature, (4) derived estimations of the maximum secondary yield value for the LP surface without using laboratory measurements, and (5) showed how to model the energetic contributions to the DC level and slope of the (I-V) curve via several methods (empirically and theoretically). This work will allow, for the whole Cassini mission, to clean the measurements influenced by such electrons. Furthermore, the understanding of this influence may be used for other missions using Langmuir probes, such as the future missions Jupiter Icy Moons Explorer at Jupiter, BepiColombo at Mercury, Rosetta at the comet Churyumov-Gerasimenko, and even the probes onboard spacecrafts in the Earth magnetosphere
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Upwelling O+ ion source characteristics
Recent observations from the Dynamics Explorer 1 (DE-1) spacecraft have shown that the dayside auroral zone is an important source of very low-energy superthermal O^+ ions for the polar magnetosphere. When observed at 2000- to 5000-km altitude, the core of the O^+ distribution exhibits transverse heating to energies on the order of 10 eV, significant upward heat flux, and subsonic upward flow at significant flux levels exceeding 10^8 cm^{-2}s^{-1}. The term "upwelling ions" has been adopted to label these flows, which stand out in sharp contrast to the light ion polar wind flows observed in the same altitude range in the polar cap and subauroral magnetosphere. We have chosen a typical upwelling ion event for detailed study, correlating retarding ion mass spectrometer observations of the low-energy plasma with energetic ion observations and local electromagnetic field observations. The upwelling ion signature is colocated with the magnetospheric cleft as marked by precipitating energetic magnetosheath ions. The apparent ionospheric heating is clearly linked with the magnetic field signatures of strong field-aligned currents in the vicinity of the dayside polar cap boundary. Electric field and ion plasma measurements indicate that a very strong and localized convection channel or jet exists coincident with the other signatures of this event. These observations indicate that transverse ion heating to temperatures on the order of 10^5 K in the 2000- to 5000-km ionosphere is an important factor in producing heavy ion outflows into the polar magnetosphere. This result contrasts with recent suggestions that electron heating to temperatures of order 10^4 K is the most important parameter with regard to O^+ outflow
A Sensitivity Study of the Enceladus Torus
We have developed a homogeneous model of physical chemistry to investigate
the neutral-dominated, water-based Enceladus torus. Electrons are treated as
the summation of two isotropic Maxwellian distributionsa thermal component
and a hot component. The effects of electron impact, electron recombination,
charge exchange, and photochemistry are included. The mass source is neutral
HO, and a rigidly-corotating magnetosphere introduces energy via pickup of
freshly-ionized neutrals. A small fraction of energy is also input by Coulomb
collisions with a small population ( 1%) of supra-thermal electrons. Mass
and energy are lost due to radial diffusion, escaping fast neutrals produced by
charge exchange and recombination, and a small amount of radiative cooling. We
explore a constrained parameter space spanned by water source rate, ion radial
diffusion, hot-electron temperature, and hot-electron density. The key findings
are: (1) radial transport must take longer than 12 days; (2) water is input at
a rate of 100--180 kg s; (3) hot electrons have energies between 100 and
250 eV; (4) neutrals dominate ions by a ratio of 40:1 and continue to dominate
even when thermal electrons have temperatures as high as 5 eV; (5)
hot electrons do not exceed 1% of the total electron population within the
torus; (6) if hot electrons alone drive the observed longitudinal variation in
thermal electron density, then they also drive a significant variation in ion
composition.Comment: 9 pages text, 3 tables, 9 figure
Magnetic signatures of plasma-depleted flux tubes in the Saturnian inner magnetosphere
Initial Cassini observations have revealed evidence for interchanging magnetic flux tubes in the inner Saturnian magnetosphere. Some of the reported flux tubes differ remarkably by their magnetic signatures, having a depressed or enhanced magnetic pressure relative to their surroundings. The ones with stronger fields have been interpreted previously as either outward moving mass-loaded or inward moving plasma-depleted flux tubes based on magnetometer observations only. We use detailed multi-instrumental observations of small and large density depletions in the inner Saturnian magnetosphere from Cassini Rev. A orbit that enable us to discriminate amongst the two previous and opposite interpretations. Our analysis undoubtedly confirms the similar nature of both types of reported interchanging magnetic flux tubes, which are plasma-depleted, whatever their magnetic signatures are. Their different magnetic signature is clearly an effect associated with latitude. These Saturnian plasma-depleted flux tubes ultimately may play a similar role as the Jovian ones
Cryo-FIB Machining: An Alternative to TEM Cryo-Sections Cut with Diamonds?
Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7-August 11, 201
Recreational sea fishing in Belgium: Monitoring the capacity, intensity and density at sea (first results)
Survey of Saturn Z-mode Emission
Because of the role of Z-mode emission in the diffusive scattering and resonant acceleration of electrons, we conduct a survey of intensity in the Saturn inner magnetosphere. Z-mode is primarily observed as “5 kHz” narrowband emission in the lower density regions where the ratio of cyclotron to plasma frequency, fc/fp > 1 to which we limit this study. This occurs at Saturn along the inner edge of the Enceladus torus near the equator and at higher latitudes. We present profiles and parametric fits of intensity as a function of frequency, radius, latitude, and local time. The magnetic field intensity levels are lower than chorus, but the electric field intensities are comparable. We conclude that Z-mode wave-particle interactions may make a significant contribution to electron acceleration in the inner magnetosphere of Saturn, supplementing acceleration produced by chorus emission
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