70 research outputs found

    Application Areas of the Shared Service Concept within the Romanian Health System

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    The Romanian healthcare system can be characterized by chronic under financing, leading to poor services towards the patients, corruption and high debts of the public institutions towards their suppliers. In order to cope with the situation, the Romanian state approved in 2010 the emergency ordinance 48/2010 on the decentralization of the health systems. Due to this legislation more than 370 hospitals across the country had been transferred under the administration of local public administration officials, whereas only roundabout 60 hospitals remained under the control of the Ministry of Health. As a consequence, local authorities have to familiarize themselves with questions concerning the proper management of the assigned hospitals. The present paper explores the different application areas of the shared service concept and the benefits this concept can add to the healthcare system. Three areas from the administration and from the operative function of the hospitals had exemplarily been selected in order to demonstrate the potential of shared services in terms of reducing the existing costs, while increasing the quality and performance of the services in question. In order to provide a holistic picture, possible disadvantages are highlighted and explained. The paper concludes that the benefits of the shared service concept can counterbalance the possible negative aspects and support the Romanian health system in overcoming this crisis and improve overall performance.Healthcare, Local Public Services, Shared Services, Contracting out, Privatization

    Interplay between Kondo effect and Ruderman-Kittel-Kasuya-Yosida interaction

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    The interplay between the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction and the Kondo effect is expected to provide the driving force for the emergence of many phenomena in strongly correlated electron materials. Two magnetic impurities in a metal are the smallest possible system containing all these ingredients and define a bottom up approach towards a long term understanding of concentrated / dense systems. Here we report on the experimental and theoretical investigation of iron dimers buried below a Cu(100) surface by means of low temperature scanning tunnelling spectroscopy (STS) combined with density functional theory (DFT) and numerical renormalization group (NRG) calculations. The Kondo effect, in particular the width of the Abrikosov-Suhl resonance, is strongly altered or even suppressed due to magnetic coupling between the impurities. It oscillates as function of dimer separation revealing that it is related to the RKKY interaction mediated by the conduction electrons. Simulations based on density functional theory support this concept showing the same oscillation period and trends in the coupling strength as found in the experiment

    Magnetotransport on the nano scale

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    Transport experiments in strong magnetic fields show a variety of fascinating phenomena like the quantum Hall effect, weak localization or the giant magnetoresistance. Often they originate from the atomic-scale structure inaccessible to macroscopic magnetotransport experiments. To connect spatial information with transport properties, various advanced scanning probe methods have been developed. Capable of ultimate spatial resolution, scanning tunnelling potentiometry has been used to determine the resistance of atomic-scale defects such as steps and interfaces. Here we combine this technique with magnetic fields and thus transfer magnetotransport experiments to the atomic scale. Monitoring the local voltage drop in epitaxial graphene, we show how the magnetic field controls the electric field components. We find that scattering processes at localized defects are independent of the strong magnetic field while monolayer and bilayer graphene sheets show a locally varying conductivity and charge carrier concentration differing from the macroscopic average

    Structure and Non-Equilibrium Heat-Transfer of a Physisorbed Molecular Layer on Graphene

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    The structure of a physisorbed sub-monolayer of 1,2-bis(4-pyridyl)ethylene (bpe) on epitaxial graphene is investigated by Low-Energy Electron Diffraction and Scanning Tunneling Microscopy. Additionally, non-equilibrium heat-transfer between bpe and the surface is studied by Ultrafast Low-Energy Electron Diffraction. Bpe arranges in an oblique unit cell which is not commensurate with the substrate. Six different rotational and/or mirror domains, in which the molecular unit cell is rotated by 28{\pm}0.1{\deg} with respect to the graphene surface, are identified. The molecules are weakly physisorbed, as evidenced by the fact that they readily desorb at room temperature. At liquid nitrogen temperature, however, the layers are stable and time-resolved experiments can be performed. The temperature changes of the molecules and the surface can be measured independently through the Debye-Waller factor of their individual diffraction features. Thus, the heat flow between bpe and the surface can be monitored on a picosecond timescale. The time-resolved measurements, in combination with model simulations, show the existence of three relevant thermal barriers between the different layers. The thermal boundary resistance between the molecular layer and graphene was found to be 2{\pm}1{\cdot}10-8 K m2 W-1

    Theory of real space imaging of Fermi surfaces

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    A scanning tunneling microscope can be used to visualize in real space Fermi surfaces with buried impurities far below substrates acting as local probes. A theory describing this feature is developed based on the stationary phase approximation. It is demonstrated how a Fermi surface of a material acts as a mirror focusing electrons that scatter at hidden impurities.Comment: 10 pages, 4 figure

    Substrate induced nanoscale resistance variation in epitaxial graphene

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    Graphene, the first true two-dimensional material, still reveals the most remarkable transport properties among the growing class of two-dimensional materials. Although many studies have investigated fundamental scattering processes, the surprisingly large variation in the experimentally determined resistances is still an open issue. Here, we quantitatively investigate local transport properties of graphene prepared by polymer assisted sublimation growth using scanning tunneling potentiometry. These samples exhibit a spatially homogeneous current density, which allows to analyze variations in the local electrochemical potential with high precision. We utilize this possibility by examining the local sheet resistance finding a significant variation of up to 270% at low temperatures. We identify a correlation of the sheet resistance with the stacking sequence of the 6H silicon carbide substrate and with the distance between the graphene and the substrate. Our results experimentally quantify the impact of the graphene-substrate interaction on the local transport properties of graphene

    Long-range Kondo signature of a single magnetic impurity

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    The Kondo effect, one of the oldest correlation phenomena known in condensed matter physics, has regained attention due to scanning tunneling spectroscopy (STS) experiments performed on single magnetic impurities. Despite the sub-nanometer resolution capability of local probe techniques one of the fundamental aspects of Kondo physics, its spatial extension, is still subject to discussion. Up to now all STS studies on single adsorbed atoms have shown that observable Kondo features rapidly vanish with increasing distance from the impurity. Here we report on a hitherto unobserved long range Kondo signature for single magnetic atoms of Fe and Co buried under a Cu(100) surface. We present a theoretical interpretation of the measured signatures using a combined approach of band structure and many-body numerical renormalization group (NRG) calculations. These are in excellent agreement with the rich spatially and spectroscopically resolved experimental data.Comment: 7 pages, 3 figures + 8 pages supplementary material; Nature Physics (Jan 2011 - advanced online publication
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