495 research outputs found

    Once again: Instanton method vs. WKB

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    A recent analytic test of the instanton method performed by comparing the exact spectrum of the Lameˊ{\acute e} potential (derived from representations of a finite dimensional matrix expressed in terms of su(2)su(2) generators) with the results of the tight--binding and instanton approximations as well as the standard WKB approximation is commented upon. It is pointed out that in the case of the Lameˊ{\acute e} potential as well as others the WKB--related method of matched asymptotic expansions yields the exact instanton result as a result of boundary conditions imposed on wave functions which are matched in domains of overlap.Comment: 10 pages, no figures. References list revised according to JHE

    Leguminosenkörnerschrote und andere vegetabile Dünger im Ökologischen Gemüsebau

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    The potential of different plant based organic fertilisers (PBOF) to substitute animal based organic fertilisers (ABOF) in organic vegetable production were investigated in incubation, pot and field experiments. PBOFs have the potential to replace ABOFs. Particularly legume seed meals show fast net N-release even at low soil temperatures. Considerable differences in nitrate contents of vegetables can be found between the different fertilisers although fresh matter and N yields are nearly identical

    Unternehmensplanung

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    D-Branes and their Absorptivity in Born-Infeld Theory

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    Standard methods of nonlinear dynamics are used to investigate the stability of particles, branes and D-branes of abelian Born-Infeld theory. In particular the equation of small fluctuations about the D-brane is derived and converted into a modified Mathieu equation and - complementing earlier low-energy investigations in the case of the dilaton-axion system - studied in the high-energy domain. Explicit expressions are derived for the S-matrix and absorption and reflection amplitudes of the scalar fluctuation in the presence of the D-brane. The results confirm physical expectations and numerical studies of others. With the derivation and use of the (hitherto practically unknown) high energy expansion of the Floquet exponent our considerations also close a gap in earlier treatments of the Mathieu equation.Comment: latex, 26 pages, 4 figures, one reference added, to appear in Nucl. Phys.

    Coherent States of the Deformed Heisenberg-Weyl Algebra in Noncommutative Space

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    In two-dimensional space a subtle point that for the case of both space-space and momentum-momentum noncommuting, different from the case of only space-space noncommuting, the deformed Heisenberg-Weyl algebra in noncommutative space is not completely equivalent to the undeformed Heisenberg-Weyl algebra in commutative space is clarified. It follows that there is no well defined procedure to construct the deformed position-position coherent state or the deformed momentum-momentum coherent state from the undeformed position-momentum coherent state. Identifications of the deformed position-position and deformed momentum-momentum coherent states with the lowest energy states of a cold Rydberg atom in special conditions and a free particle, respectively, are demonstrated.Comment: 10 pages, no figur

    Quinpramine Ameliorates Rat Experimental Autoimmune Neuritis and Redistributes MHC Class II Molecules

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    Activation of inflammatory cells is central to the pathogenesis of autoimmune demyelinating diseases of the peripheral nervous system. The novel chimeric compound quinpramine—generated from imipramine and quinacrine—redistributes cholesterol rich membrane domains to intracellular compartments. We studied the immunological and clinical effects of quinpramine in myelin homogenate induced Lewis rat experimental autoimmune neuritis (EAN), a model system for acute human inflammatory neuropathies, such as the Guillain-Barré syndrome. EAN animals develop paresis of all limbs due to autoimmune inflammation of peripheral nerves. Quinpramine treatment ameliorated clinical disease severity of EAN and infiltration of macrophages into peripheral nerves. It reduced expression of MHC class II molecules on antigen presenting cells and antigen specific T cell proliferation both in vitro and in vivo. Quinpramine exerted its anti-proliferatory effect on antigen presenting cells, but not on responder T cells. Our data suggest that quinpramine represents a candidate pharmaceutical for inflammatory neuropathies

    Pharmacogenetic Analysis of Voriconazole Treatment in Children

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    Voriconazole is among the first-line antifungal drugs to treat invasive fungal infections in children and known for its pronounced inter- and intraindividual pharmacokinetic variability. Polymorphisms in genes involved in the metabolism and transport of voriconazole are thought to influence serum concentrations and eventually the therapeutic outcome. To investigate the impact of these genetic variants and other covariates on voriconazole trough concentrations, we performed a retrospective data analysis, where we used medication data from 36 children suffering from invasive fungal infections treated with voriconazole. Data were extracted from clinical information systems with the new infrastructure SwissPKcdw, and linear mixed effects modelling was performed using R. Samples from 23 children were available for DNA extraction, from which 12 selected polymorphism were genotyped by real-time PCR. 192 (49.1%) of 391 trough serum concentrations measured were outside the recommended range. Voriconazole trough concentrations were influenced by polymorphisms within the metabolizing enzymes CYP2C19 and CYP3A4, and within the drug transporters ABCC2 and ABCG2, as well as by the co-medications ciprofloxacin, levetiracetam, and propranolol. In order to prescribe an optimal drug dosage, pre-emptive pharmacogenetic testing and careful consideration of co-medications in addition to therapeutic drug monitoring might improve voriconazole treatment outcome of children with invasive fungal infections. Keywords: ABCC2; ABCG2; CYP2C19; CYP3A4; children; non-linear mixed effects modelling; pediatric pharmacology; pharmacogenetics; therapeutic drug monitoring; voriconazol

    Angular Momentum of Supersymmetric Cold Rydberg Atoms

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    Semiunitary transformation is applied to discuss supersymmetrization of cold Rydberg atoms. In the limit of vanishing kinetic energy the lowest angular momentum of the supersymmetric cold Rydberg atom is 3/23\hbar/2. A possible experimental verification is suggested.Comment: 11 pages, no figur

    Management of biliary obstruction in patients with newly diagnosed alveolar echinococcosis: a Swiss retrospective cohort study

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    BACKGROUND AND STUDY AIMS: Alveolar echinococcosis, an orphan zoonosis affecting the liver, is of increasing concern worldwide. Most symptomatic cases present at an advanced and inoperable stage, sometimes with biliary obstruction prompting biliary tract interventions. These are, however, associated with a high risk of infectious complications. The aim of this retrospective study was to compare the effectiveness and safety of conservative and interventional treatment approaches in patients with newly diagnosed alveolar echinococcosis and biliary obstruction. PATIENTS AND METHODS: Alveolar echinococcosis patients treated at two referral centres in Switzerland, presenting with hyperbilirubinaemia (total bilirubin >1.5 Upper Limit of Normal) at diagnosis were included, unless another underlying aetiology, i.e. common bile duct stones or decompensated cirrhosis, was identified. Patients were divided into two groups, according to whether they initially received a biliary tract intervention. The primary endpoint was normalisation of bilirubin levels within a 6-month period. Secondary endpoints included, among others, the occurrence of early and late biliary complications, the need for biliary tract interventions during follow-up and overall duration of hospital stays for treatment initiation and for biliary complications. RESULTS: 28 patients were included in this study, of whom 17 received benzimidazole therapy alone and 11 additionally received a biliary tract intervention. Baseline characteristics did not differ between groups. All but one patient in each group achieved the primary endpoint (p=0.747). Biliary tract intervention was associated with faster laboratory improvement (t1/2 1.3 vs 3.0 weeks), but also with more frequent early biliary complications (7/11 vs 1/17, p=0.002) and longer initial hospital stay (18 days vs 7 days, p=0.007). CONCLUSION: Biliary obstruction in patients with newly diagnosed alveolar echinococcosis can be treated effectively with benzimidazole therapy alone. Biliary tract intervention, on the other hand, is associated with a high complication rate and should probably be reserved for patients with insufficient response to benzimidazole therapy
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