12,938 research outputs found

    New public management reform in European countries: The retreat of the state from telecommunication services

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    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

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    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

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    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

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    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 228^{228}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

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    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

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    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 (15\sim 15'') \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

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    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

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    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
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