581 research outputs found

    Superconductivity, Electron Paramagnetic Resonance, and Raman Scattering Studies of Heterofullerides with Cs and Mg

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    In the present study, the results of investigation of physical properties of heterofullerides A3−xMxC60 (A=K, Rb, Cs, M=Be, Mg, Ca, Al, Fe, Tl, x=1,2); as well as RbCsTlC60, KCsTlC60, and KMg2C60 are described. All of the fullerides were synthesized by the exchange reactions of alkaline fullerides with anhydrous metal halides. Superconductivity was found in RbCsTlC60 and KCsTlC60

    THROMBOLYTIC THERAPY IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION

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    It is reported that the implementation in clinical practice thrombolytic (fibrinolytic) therapy resulted inmortality reduction during firstmonth after myocardial infarction from 17-18% to 5-8%. Different details of this therapy are considered: terms of thrombolysis since the beginning of myocardial infarction, alternative methods of coronary blood flow recovery , indications and contraindications, complications and side effects, estimation of thrombolysis efficacy. Fibrin-selective and fibrin-non-selective drugs are presented. Different fibrinolytics are described: streptokinase, anistreplase, alteplase, reteplase, tenekteplase. The results of large randomized clinical trials devoted to fibrinolytic therapy of myocardial infarction are analyzed: GISSI, ISSIS, TIMI, GUSTO, INJECT, ASSENT. The possibility to increase in efficacy and safety of fibrinolytics by their combination with acetylsalicylic acid, IIb/IIIa receptor inhibitors and heparins are discussed

    Direct detection of a magnetic field in the photosphere of the single M giant EK Boo: How common is magnetic activity among M giants?

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    We study the fast rotating M5 giant EK Boo by means of spectropolarimetry to obtain direct and simultaneous measurements of both the magnetic field and activity indicators, in order to infer the origin of the activity in this fairly evolved giant. We used the new spectropolarimeter NARVAL at the Bernard Lyot Telescope (Observatoire du Pic du Midi, France) to obtain a series of Stokes I and Stokes V profiles for EK Boo. Using the Least Square Deconvolution technique we were able to detect the Zeeman signature of the magnetic field. We measured its longitudinal component by means of the averaged Stokes V and Stokes I profiles. The spectra also permitted us to monitor the CaII K&H chromospheric emission lines, which are well known as indicators of stellar magnetic activity. From ten observations obtained between April 2008 and March 2009, we deduce that EK Boo has a magnetic field, which varied in the range of -0.1 to -8 G. We also determined the initial mass and evolutionary stage of EK Boo, based on up-to-date stellar evolution tracks. The initial mass is in the range of 2.0-3.6 M_sun, and EK Boo is either on the asymptotic giant branch (AGB), at the onset of the thermal pulse phase, or at the tip of the first (or red) giant branch (RGB). The fast rotation and activity of EK Boo might be explained by angular momentum dredge-up from the interior, or by the merging of a binary. In addition, we observed eight other M giants, which are known as X-ray emitters, or to be rotating fast for their class. For one of these, beta And, presumably also an AGB star, we have a marginal detection of magnetic field, and a longitudinal component Bl of about 1G was measured. More observations like this will answer the question whether EK Boo is a special case, or whether magnetic activity is, rather, more common among M giants than expected.Comment: Accepted for publication in Astronomy & Astrophysics, 10 pages, 8 figure

    Simultaneous monitoring of the photometric and polarimetric activity of the young star PV Cep in the optical/near-infrared bands

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    We present the results of a simultaneous monitoring, lasting more than 2 years, of the optical and near-infrared photometric and polarimetric activity of the variable protostar PV Cep. During the monitoring period, an outburst has occurred in all the photometric bands, whose declining phase (Δ\DeltaJ \approx 3 mag) lasted about 120 days. A time lag of \sim 30 days between optical and infrared light curves has been measured and interpreted in the framework of an accretion event. This latter is directly recognizable in the significant variations of the near-infrared colors, that appear bluer in the outburst phase, when the star dominates the emission, and redder in declining phase, when the disk emission prevails. All the observational data have been combined to derive a coherent picture of the complex morphology of the whole PV Cep system, that, in addition to the star and the accretion disk, is composed also by a variable biconical nebula. In particular, the mutual interaction between all these components is the cause of the high value of the polarization (\approx 20%) and of its fluctuations. The observational data concur to indicate that PV Cep is not a genuine EXor star, but rather a more complex object; moreover the case of PV Cep leads to argue about the classification of other recently discovered young sources in outburst, that have been considered, maybe over-simplifying, as EXor.Comment: Accepted for publication on Ap

    High-Q trenched aluminum coplanar resonators with an ultrasonic edge microcutting for superconducting quantum devices

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    Dielectric losses are one of the key factors limiting the coherence of superconducting qubits. The impact of materials and fabrication steps on dielectric losses can be evaluated using coplanar waveguide (CPW) microwave resonators. Here, we report on superconducting CPW microwave resonators with internal quality factors systematically exceeding 5x106 at high powers and 2x106 (with the best value of 4.4x106) at low power. Such performance is demonstrated for 100-nm-thick aluminum resonators with 7-10.5 um center trace on high-resistivity silicon substrates commonly used in quantum Josephson junction circuits. We investigate internal quality factors of the resonators with both dry and wet aluminum etching, as well as deep and isotropic reactive ion etching of silicon substrate. Josephson junction compatible CPW resonators fabrication process with both airbridges and silicon substrate etching is proposed. Finally, we demonstrate the effect of airbridges positions and extra process steps on the overall dielectric losses. The best quality fa ctors are obtained for the wet etched aluminum resonators and isotropically removed substrate with the proposed ultrasonic metal edge microcutting.Comment: 6 pages, 2 figure

    Management of students professional competencies formation on the basis of interdisciplinary integration

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    © 2016, Econjournals. All rights reserved.The relevance of the study is conditioned by the modernization of professional training the leading strategy of which is the formation of professional competencies. Professional education is characterized by the desire to overcome the professional isolation and to develop a more democratic and effective professional training systems focused on competitive creative professional. The purpose of the article is to provide a control mechanism for the formation of professional competencies of future specialists on the basis of interdisciplinary integration. The leading method has become the method of action research, which allows gaining of new knowledge about the future specialists’ professional training, focused on the formation of entity-entity relations, personal meanings and life values on the basis of interdisciplinary integration. The article reveals leading trends in the development of future specialists’ professional training (reforming, accessibility, solidity and continuity); structure-forming components of professional competencies are allocated (epistemological, normative and functional); the peculiarities of future specialists’ professional competencies formation on the basis of interdisciplinary integration are clarified (focus on holistic education throughout life; upbringing of sustainable civil qualities of the person; the relationship of academic disciplines, ensuring complementarities of content, forms, methods and means of professional training and the creation of common educational modules for various logical reasons); the idea of case-method implementation in the training process is suggested. The paper submissions can be useful for teachers of research universities; centers to enhance personnel training and retraining while selecting and structuring of the content for professional development of the research universities’ teaching staff

    Electronic structure and luminescence properties of Ca2Ge7O16:Dy3+

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    The present report represents an overview of the results of a combined experimental-computational study of electronic structure, thermoluminescence (TL) and afterglow properties of Ca2Ge7O16:Dy3+ synthesized for the first time. Afterglow curves of Ca2Ge7O16:Dy3+ at 575 nm showing persistent luminescence have been described in Becquerel law. The TL measurements reveal at least one TL band at 326 K and two luminescence bands at 475 and 535 nm. Persistent luminescence in Ca2Ge7O16:Dy3+ originates from relatively shallow charge traps with high probability of charge carriers recapture. The model of energy processes, configurations of traps and luminescence centers has been proposed with the aid of ab initio calculations performed using the LCAO approximation and several hybrid functionals
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