12,938 research outputs found
New public management reform in European countries: The retreat of the state from telecommunication services
In the post war period, telecommunications - being services of 'general economic interest' - were initially managed by public administrative bodies in many Western European countries. With the rise of New Public Management (NPM) in the 1980s, these bodies were often transformed into public corporations or joint stock companies. Following corporatisation, the provision and the management of these services of general economic interest was gradually transferred to private actors. This paper analyses whether privatisation, as part of NPM reforms, has benefited the consumer. We have, therefore, compiled data on privatisation in the telecommunication sector for 15 European countries from 1980 to 2006. The data set covers the corporatisation process, as well as the transfer of the service provision to the private sector. Three empirical findings stand out: first, the reform processes have differed widely from each other. Second, it's not just the transfer of ownership to the private sector that has ensured efficiency gains and increased consumer benefits; corporatisation has done this as well. Third, efficiency gains have been transferred to the consumer, especially at the beginning of the reform process. -- In der Nachkriegszeit wurden Telekommunikationsdienstleistungen in vielen westeuropäischen Ländern zumeist von Verwaltungseinheiten bereitgestellt. Mit dem Aufkommen des New Public Managements (NPMs) in den 1980er Jahren wurden diese Verwaltungseinheiten in öffentlich-rechtliche Unternehmen oder Aktiengesellschaften umgewandelt (=formelle Privatisierung) und anschließend stückweise an private Akteure übertragen (=materielle Privatisierung). Dieser Beitrag untersucht, ob die Konsumenten von diesen Privatisierungsmaßnahmen profitieren konnten. Zur Beantwortung dieser Frage wurde ein vollständig neuer Paneldatensatz zusammengestellt, mit dem die Privatisierung im Telekommunikationssektor für 15 europäische Länder von 1980 bis 2006 abgebildet werden kann. Der Datensatz umfasst erstmals sowohl formelle als auch materielle Privatisierungsschritte. Drei empirische Ergebnisse sind besonders hervorzuheben. Erstens, der Privatisierungsprozess unterscheidet sich teilweise erheblich zwischen den Ländern. Zweitens, die Konsumenten konnten nicht nur vom Verkauf von Unternehmensanteilen profitieren, sondern auch von formellen Privatisierungsmaßnahmen. Drittens, Effizienzgewinne wurden insbesondere am Anfang des Reformprozesses an die Konsumenten weitergegeben.
Quantization of the electromagnetic field outside static black holes and its application to low-energy phenomena
We discuss the Gupta-Bleuler quantization of the free electromagnetic field
outside static black holes in the Boulware vacuum. We use a gauge which reduces
to the Feynman gauge in Minkowski spacetime. We also discuss its relation with
gauges used previously. Then we apply the low-energy sector of this field
theory to investigate some low-energy phenomena. First, we discuss the response
rate of a static charge outside the Schwarzschild black hole in four
dimensions. Next, motivated by string physics, we compute the absorption cross
sections of low-energy plane waves for the Schwarzschild and extreme
Reissner-Nordstr\"om black holes in arbitrary dimensions higher than three.Comment: 26 pages (revtex), no figures, misprints in some conditions correcte
Plasmon Evolution and Charge-Density Wave Suppression in Potassium Intercalated Tantalum Diselenide
We have investigated the influence of potassium intercalation on the
formation of the charge-density wave (CDW) instability in 2H-tantalum
diselenide by means of Electron Energy-Loss Spectroscopy and density functional
theory. Our observations are consistent with a filling of the conduction band
as indicated by a substantial decrease of the plasma frequency in experiment
and theory. In addition, elastic scattering clearly points to a destruction of
the CDW upon intercalation as can be seen by a vanishing of the corresponding
superstructures. This is accompanied by a new superstructure, which can be
attributed to the intercalated potassium. Based on the behavior of the c-axis
upon intercalation we argue in favor of interlayer-sites for the alkali-metal
and that the lattice remains in the 2H-modification
Deep learning based pulse shape discrimination for germanium detectors
Experiments searching for rare processes like neutrinoless double beta decay
heavily rely on the identification of background events to reduce their
background level and increase their sensitivity. We present a novel machine
learning based method to recognize one of the most abundant classes of
background events in these experiments. By combining a neural network for
feature extraction with a smaller classification network, our method can be
trained with only a small number of labeled events. To validate our method, we
use signals from a broad-energy germanium detector irradiated with a Th
gamma source. We find that it matches the performance of state-of-the-art
algorithms commonly used for this detector type. However, it requires less
tuning and calibration and shows potential to identify certain types of
background events missed by other methods.Comment: Published in Eur. Phys. J. C. 9 pages, 10 figures, 3 table
Avalanches in a Bose-Einstein condensate
Collisional avalanches are identified to be responsible for an 8-fold
increase of the initial loss rate of a large 87-Rb condensate. We show that the
collisional opacity of an ultra-cold gas exhibits a critical value. When
exceeded, losses due to inelastic collisions are substantially enhanced. Under
these circumstances, reaching the hydrodynamic regime in conventional BEC
experiments is highly questionable.Comment: 4 pages, 2 figures, 1 tabl
Polarization of the \lya Halos Around Sources Before Cosmological Reionization
In Loeb & Rybicki (1999; paper I) it was shown that before reionization, the
scattering of \lya photons from a cosmological source might lead to a fairly
compact () \lya halo around the source. Observations of such halos
could constrain the properties of the neutral intergalactic medium (IGM), and
in particular yield the cosmological density parameters of baryons and matter
on scales where the Hubble flow is unperturbed. Paper I did not treat the
polarization of this scattered radiation, but did suggest that the degree of
such polarization might be large. In this Letter we report on improved
calculations for these \lya halos, now accounting for the polarization of the
radiation field. The polarization is linear and is oriented tangentially to the
projected displacement from the center of the source. The degree of
polarization is found to be 14% at the core radius, where the intensity has
fallen to half of the central value. It rises to 32% and 45% at the radii where
the intensity has fallen to one-tenth and one-hundreth of the central
intensity, respectively. At larger radii the degree of polarization rises
further, asymptotically to 60%. Such high values of polarization should be
easily observable and provide a clear signature of the phenomenon of \lya halos
surrounding sources prior to reionization.Comment: 8 pages, 2 Postscript figures, accepted by Astrophysical Journal
Letters; some typos corrected; added two paragraphs at the end of section 3
concerning detectability of Lyman alpha halo
Semi-Automated SVG Programming via Direct Manipulation
Direct manipulation interfaces provide intuitive and interactive features to
a broad range of users, but they often exhibit two limitations: the built-in
features cannot possibly cover all use cases, and the internal representation
of the content is not readily exposed. We believe that if direct manipulation
interfaces were to (a) use general-purpose programs as the representation
format, and (b) expose those programs to the user, then experts could customize
these systems in powerful new ways and non-experts could enjoy some of the
benefits of programmable systems.
In recent work, we presented a prototype SVG editor called Sketch-n-Sketch
that offered a step towards this vision. In that system, the user wrote a
program in a general-purpose lambda-calculus to generate a graphic design and
could then directly manipulate the output to indirectly change design
parameters (i.e. constant literals) in the program in real-time during the
manipulation. Unfortunately, the burden of programming the desired
relationships rested entirely on the user.
In this paper, we design and implement new features for Sketch-n-Sketch that
assist in the programming process itself. Like typical direct manipulation
systems, our extended Sketch-n-Sketch now provides GUI-based tools for drawing
shapes, relating shapes to each other, and grouping shapes together. Unlike
typical systems, however, each tool carries out the user's intention by
transforming their general-purpose program. This novel, semi-automated
programming workflow allows the user to rapidly create high-level, reusable
abstractions in the program while at the same time retaining direct
manipulation capabilities. In future work, our approach may be extended with
more graphic design features or realized for other application domains.Comment: In 29th ACM User Interface Software and Technology Symposium (UIST
2016
Numerical Studies of Fano Resonance in Quantum dots Embedded in AB Rings
The Fano resonance in quantum dots embedded in Aharonov-Bohm rings is
examined theoretically, using two models of non-interacting electrons. The
first model yields an analytical expression for the conductance G. G is written
in an extended Fano form with a complex parameter. The shape of the resonance
can be asymmetric or symmetric, depending on the magnetic flux enclosed in the
ring. The "phase" of the resonance is changed continuously with increasing the
flux in two-terminal situations. These are in accordance with recent
experimental results. In the second model, we consider the dephasing effect on
the Fano resonance by numerical calculations.Comment: 2 pages, 4 figures, to appear in J. Phys. Soc. Jpn., proceedings of
International Conference on Quantum Transport and Quantum Coherence
(Localisation 2002, Tokyo
- …
