3,678 research outputs found

    Vibrations on pulse tube based Dry Dilution Refrigerators for low noise measurements

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    Dry Dilution Refrigerators (DDR) based on pulse tube cryo-coolers have started to replace Wet Dilution Refrigerators (WDR) due to the ease and low cost of operation. However these advantages come at the cost of increased vibrations, induced by the pulse tube. In this work, we present the vibration measurements performed on three different commercial DDRs. We describe in detail the vibration measurement system we assembled, based on commercial accelerometers, conditioner and DAQ, and examined the effects of the various damping solutions utilized on three different DDRs, both in the low and high frequency regions. Finally, we ran low temperature, pseudo-massive (30 and 250 g) germanium bolometers in the best vibration-performing system under study and report on the results

    Forced and free response of the Adriatic Sea level

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    The aim of this paper is to improve the knowledge of the variations of the sea level in the Adriatic Sea in the domains of forced and free oscillations. For this purpose, one-year long-time series of data collected at nine tide gauge stations placed on the eastern shoreline have been collected and processed by spectral analysis. The harmonic constituents have been calculated too. Semidiurnal and diurnal tides have got larger variations of amplitude on the islands than on the coast. The response of the sea level in the domain of synoptic and planetary formations is quite synchronous in the whole Adriatic for periods longer than 3.5 days, with a gap around 9.5 days. These formations excite the sea level first in the North Adriatic, and then, secondly in the Middle and South Adriatic. The seiches occurred at already known periods of 22-23, 10.8 and 7.5-8 hours, and at a new one of about 4 hours. 4 hour seiche occurs in the region inside the Middle Adriatic islands, and it is predominantly influenced by the Sirocco wind forcing

    The Establishment of International Mechanisms for Enforcing Provisional Orders and Final Judgments Arising From Securities Law Violations

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    In the 1980s and early 1990s, securities regulators have made substantial progress in developing cooperative relationships to reduce the value of international borders as barriers to the detection and prosecution of securities fraud, but there needs to be an establishment of international mechanisms for enforcing provisional orders and final judgments. The development of mechanisms pursuant to which regulators can assist each other in freezing assets and recovering illicit profits is discussed

    Ferromagnetism in the Periodic Anderson Model - a Modified Alloy Analogy

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    We introduce a new aproximation scheme for the periodic Anderson model (PAM). The modified alloy approximation represents an optimum alloy approximation for the strong coupling limit, which can be solved within the CPA-formalism. Zero-temperature and finite-temperature phase diagrams are presented for the PAM in the intermediate-valence regime. The diversity of magnetic properties accessible by variation of the system parameters can be studied by means of quasiparticle densities of states: The conduction band couples either ferro- or antiferromagneticaly to the f-levels. A finite hybridization is a necessary precondition for ferromagnetism. However, too strong hybridization generally suppresses ferromagnetism, but can for certain system parameters also lead to a semi-metallic state with unusual magnetic properties. By comparing with the spectral density approximation, the influence of quasiparticle damping can be examined.Comment: 20 pages, 13 figure

    Transient band keratopathy associated with ocular inflammation and systemic hypercalcemia

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    Anat Galor, Henry A Leder, Jennifer E Thorne, James P DunnThe Wilmer Eye Institute, Department of Ophthalmology, the Johns Hopkins University School of MedicinePurpose: To report a case of visually significant band keratopathy associated with ocular inflammation and systemic hypercalcemia which markedly decreased in severity after treatment of these underlying factors.Methods: Retrospective case report.Results: A 53-year-old Asian female with granulomatous panuveitis in the left eye presented with diffuse band keratopathy through the central cornea. The serum calcium was elevated. The patient was treated with topical prednisolone acetate 1% and oral prednisone with marked improvement in inflammation. The band keratopathy lessened in severity with clearing of the central cornea and improvement in visual acuity.Conclusions: Early medical treatment of underlying factors may allow reversal of band keratopathy.Keywords: ocular inflammation, transient band keratopath

    Functional approaches to infrared Yang-Mills theory in the Coulomb gauge

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    We present the current status of ongoing efforts to use functional methods, Dyson-Schwinger equations and functional renormalization group equations, for the description of the infrared regime of nonabelian (pure) gauge theories in the Coulomb gauge. In particular, we present a new determination of the color-Coulomb potential with the help of the functional renormalization group that results in an almost linearly rising potential between static color charges at large spatial distances.Comment: 11 pages, 3 figures. Slightly improved version of J. Phys.: Conf. Ser. 287 (2011) 01202

    ‘It stays with you’: multiple evocative representations of dance and future possibilities for studies in sport and physical cultures

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    This article considers the integration of arts-based representations via poetic narratives together with artistic representation on dancing embodiment so as to continue an engagement with debates regarding multiple forms/representations. Like poetry, visual images are unique and can evoke particular kinds of emotional and visceral responses, meaning that alternative representational forms can resonate in different and powerful ways. In the article, we draw on grandparent-grandchild interactions, narrative poetry, and artistic representations of dance in order to illustrate how arts-based methods might synergise to offer new ways of ‘knowing’ and ‘seeing’. The expansion of the visual arts into interdisciplinary methodological innovations is a relatively new, and sometimes contentious approach, in studies of sport and exercise. We raise concerns regarding the future for more arts-based research in the light of an ever-changing landscape of a neoliberal university culture that demands high productivity in reductionist terms of what counts as ‘output’, often within very restricted time-frames. Heeding feminist calls for ‘slow academies’ that attempt to ‘change’ time collectively, and challenge the demands of a fast-paced audit culture, we consider why it is worth enabling creative and arts-based methods to continue to develop and flourish in studies of sport, exercise and health, despite the mounting pressures to ‘perform’
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