5,545 research outputs found

    The Topology of Foliations Formed by the Generic K-Orbits of a Subclass of the Indecomposable MD5-Groups

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    The present paper is a continuation of [13], [14] of the authors. Specifically, the paper considers the MD5-foliations associated to connected and simply connected MD5-groups such that their Lie algebras have 4-dimensional commutative derived ideal. In the paper, we give the topological classification of all considered MD5-foliations. A description of these foliations by certain fibrations or suitable actions of R2\mathbb{R}^{2} and the Connes' C*-algebras of the foliations which come from fibrations are also given in the paper.Comment: 20 pages, no figur

    Life cycle assessment of biogas production in small-scale household digesters in Vietnam

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    Small-scale household digesters have been promoted across Asia as a sustainable way of handling manure. The major advantages are that they produce biogas and reduce odor. However their disadvantages include the low recycling of nutrients, because digestate is dilute and therefore difficult to transport, and the loss of biogas as a result of cracks and the intentional release of excess biogas. In this study, life cycle assessment (LCA) methodology was used to assess the environmental impacts associated with biogas digesters in Vietnam. Handling 1,000 kg of liquid manure and 100 kg of solid manure in a system with a biogas digester reduced the impact potential from 4.4 kg carbon dioxide (CO2) equivalents to 3.2 kg CO2 equivalents compared with traditional manure management. However, this advantage could easily be compromised if digester construction is considered in the LCA or in situations where there is an excess of biogas which is intentionally released. A sensitivity analysis showed that biogas digesters could be a means of reducing global warming if methane emissions can be kept low. In terms of eutrophication, farms with biogas digesters had 3 to 4 times greater impacts. In order to make biogas digesters sustainable, methods for recycling digestates are urgently required

    Monolithic Pixel Sensors in Deep-Submicron SOI Technology

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    Monolithic pixel sensors for charged particle detection and imaging applications have been designed and fabricated using commercially available, deep-submicron Silicon-On-Insulator (SOI) processes, which insulate a thin layer of integrated full CMOS electronics from a high-resistivity substrate by means of a buried oxide. The substrate is contacted from the electronics layer through vias etched in the buried oxide, allowing pixel implanting and reverse biasing. This paper summarizes the performances achieved with a first prototype manufactured in the OKI 0.15 micrometer FD-SOI process, featuring analog and digital pixels on a 10 micrometer pitch. The design and preliminary results on the analog section of a second prototype manufactured in the OKI 0.20 micrometer FD-SOI process are briefly discussed.Comment: Proceedings of the PIXEL 2008 International Workshop, FNAL, Batavia, IL, 23-26 September 2008. Submitted to JINST - Journal of Instrumentatio

    On the theory of the vortex state in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase

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    We demonstrate that the vortex state in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase may be very different depending on the field orientation relative to the crystalline axes. We calculate numerically the upper critical field near the tricritical point taking into account the modulation of the order parameter along the magnetic field as well as the higher Landau levels. For s-wave superconductors with the anisotropy described by an elliptical Fermi surface we propose a general scheme of the analysis of the angular dependence of upper critical field at all temperatures on the basis of the exact solution for the order parameter. Our results show that the transitions (with tilting magnetic field) between different types of mixed states may be a salient feature of the FFLO phase. Moreover we discuss the reasons for the first-order phase transition into the FFLO state in the case of CeCoIn5 compound.Comment: 7 figure

    Quantum mechanics in multiply connected spaces

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    This paper analyses quantum mechanics in multiply connected spaces. It is shown that the multiple connectedness of the configuration space of a physical system can determine the quantum nature of physical observables, such as the angular momentum. In particular, quantum mechanics in compactified Kaluza-Klein spaces is examined. These compactified spaces give rise to an additional angular momentum which can adopt half-integer values and, therefore, may be identified with the intrinsic spin of a quantum particle.Comment: Latex 15 page

    Zooming in on local level statistics by supersymmetric extension of free probability

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    We consider unitary ensembles of Hermitian NxN matrices H with a confining potential NV where V is analytic and uniformly convex. From work by Zinn-Justin, Collins, and Guionnet and Maida it is known that the large-N limit of the characteristic function for a finite-rank Fourier variable K is determined by the Voiculescu R-transform, a key object in free probability theory. Going beyond these results, we argue that the same holds true when the finite-rank operator K has the form that is required by the Wegner-Efetov supersymmetry method of integration over commuting and anti-commuting variables. This insight leads to a potent new technique for the study of local statistics, e.g., level correlations. We illustrate the new technique by demonstrating universality in a random matrix model of stochastic scattering.Comment: 38 pages, 3 figures, published version, minor changes in Section

    Epidural Catheters for Cervical Epidural Steroid Injections to Target Higher Cervical Pathology: Clinical Images in Practice

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    Cervical radicular pain is commonly treated with cervical epidural steroid injections. The transforaminal approach allows for direct treatment of the steroid at a particular nerve root or level. Still, it carries a significant risk of morbidity and mortality with thromboembolism or injury to cervical vasculature. The interlaminar approach is commonly utilized as it avoids vascular structures. However, the epidural space becomes narrower at higher levels, limiting the ability to perform this approach at higher cervical levels. Cervical epidural catheters can be used and advanced to target higher cervical pathology through the interlaminar approach. We present clinical images demonstrating the utility of a cervical catheter for treating higher cervical levels

    Peripheral Nerve Stimulation After Total Knee Arthroplasty and Non-Operable Patella Fracture

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    Chronic knee pain, affecting over 25% of adults in the United States, has surged by 65% over the past two decades leading to rising functional deficits, mobility problems, and a diminished quality of life. While conservative management with pharmacologic and minimally invasive injections are pursued early in the disease process, total knee arthroplasty for refractory osteoarthritis of the knee is often considered. This procedure usually improves pain and functionality within the first three months. However, a significant portion of patients often suffer from postoperative pain that can become chronic and debilitating. We detail the case of a patient with a previous TKA as well as a non-operable patella fracture who obtained significant relief with PNS despite prior conservative and minimally invasive management

    Healthcare use for diarrhoea and dysentery in actual and hypothetical cases, Nha Trang, Viet Nam.

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    To better understand healthcare use for diarrhoea and dysentery in Nha Trang, Viet Nam, qualitative interviews with community residents and dysentery case studies were conducted. Findings were supplemented by a quantitative survey which asked respondents which healthcare provider their household members would use for diarrhoea or dysentery. A clear pattern of healthcare-seeking behaviours among 433 respondents emerged. More than half of the respondents self-treated initially. Medication for initial treatment was purchased from a pharmacy or with medication stored at home. Traditional home treatments were also widely used. If no improvement occurred or the symptoms were perceived to be severe, individuals would visit a healthcare facility. Private medical practitioners are playing a steadily increasing role in the Vietnamese healthcare system. Less than a quarter of diarrhoea patients initially used government healthcare providers at commune health centres, polyclinics, and hospitals, which are the only sources of data for routine public-health statistics. Given these healthcare-use patterns, reported rates could significantly underestimate the real disease burden of dysentery and diarrhoea
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