79 research outputs found

    Kinetic Inductance of Josephson Junction Arrays: Dynamic and Equilibrium Calculations

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    We show analytically that the inverse kinetic inductance L1L^{-1} of an overdamped junction array at low frequencies is proportional to the admittance of an inhomogeneous equivalent impedance network. The ijthij^{th} bond in this equivalent network has an inverse inductance Jijcos(θi0θj0Aij)J_{ij}\cos(\theta_i^0-\theta_j^0-A_{ij}), where JijJ_{ij} is the Josephson coupling energy of the ijthij^{th} bond, θi0\theta_i^0 is the ground-state phase of the grain ii, and AijA_{ij} is the usual magnetic phase factor. We use this theorem to calculate L1L^{-1} for square arrays as large as 180×180180\times 180. The calculated L1L^{-1} is in very good agreement with the low-temperature limit of the helicity modulus γ\gamma calculated by conventional equilibrium Monte Carlo techniques. However, the finite temperature structure of γ\gamma, as a function of magnetic field, is \underline{sharper} than the zero-temperature L1L^{-1}, which shows surprisingly weak structure. In triangular arrays, the equilibrium calculation of γ\gamma yields a series of peaks at frustrations f=12(11/N)f = \frac{1}{2}(1-1/N), where NN is an integer 2\geq 2, consistent with experiment.Comment: 14 pages + 6 postscript figures, 3.0 REVTe

    Rationale for prostaglandin I2 in bone marrow oedema – from theory to application

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    Introduction: Bone marrow oedema (BME) and avascular osteonecrosis (AVN) are disorders of unclear origin. Although there are numerous operative and non-operative treatments for AVN, pain management in patients with AVN remains challenging. Prostaglandins play an important role in inflammatory responses and cell differentiation. It is thought that prostaglandin I2 ([PGI2] or synonoma prostacyclin) and its analogues promote bone regeneration on a cellular or systemic level. The purpose of this study was to assess the curative and symptomatic efficacy of the prostacyclin analogue iloprost in BME and AVN patients. Method: We are reporting on 50 patients (117 bones) affected by BME/AVN who were treated with iloprost. Pain levels before, during and 3 and 6 months after iloprost application were evaluated by a visual analogue scale (VAS). The short form(SF)-36 health survey served to judge general health status before and after treatment. Harris Hip Score (HHS) and Knee Society Score (KSS) were performed as functional scores and MRI and X-rays before and 3 and 6 months after iloprost application served as objective parameters for morphological changes of the affected bones. Results: We found a significant improvement in pain, functional and radiological outcome in BME and early AVN stages after iloprost application, whereas patients with advanced AVN stages did not benefit from iloprost infusions. Mean pain level decreased from 5.26 (day 0) to 1.63 (6 months) and both HHS and KSS increased during follow-up. Moreover, the SF-36 increased from 353.2 (day 0) to 560.5 points (6 months). We found a significant decrease in BME on MRI scans after iloprost application. Conclusions: In addition to other drugs, iloprost may be an alternative substance which should be considered in the treatment of BME/AVN-associated pain

    Northern Togo and the world economy

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    How global is the world economy? Does it also encompass the remote corners of the Third World where subsistence agriculture still predominates and where the first hard-surface roads have yet to be built? And if it does, when did these areas become incorporated into the world economy? Whereas by 1919 northernmost Togo had hardly any economic contacts with the outside world, the impact which the Great Depression had on it serves as evidence that only 10 years later this rural periphery had lost part of its former isolated, self-sufficient existence. Since then, capitalist penetration has made further inroads into the area. With most other Third-World ‘backwaters’ having experienced similar developments since the turn of the century, today's world economy does appear to be one globe-spanning, interdependent system

    The potential of pregnant women as a sentinel population for malaria surveillance

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    With increasing spatial heterogeneity of malaria transmission and a shift of the disease burden towards older children and adults, pregnant women attending antenatal care (ANC) have been proposed as a pragmatic sentinel population for malaria surveillance. However, the representativeness of routine ANC malaria test-positivity and its relationship with prevalence in other population subgroups are yet to be investigated.; Monthly ANC malaria test-positivity data from all Tanzanian health facilities for January 2014 to May 2016 was compared to prevalence data from the School Malaria Parasitaemia Survey 2015, the Malaria Indicator Survey (MIS) 2015/16, the Malaria Atlas Project 2015, and a Bayesian model fitted to MIS data. Linear regression was used to describe the difference between malaria test-positivity in pregnant women and respective comparison groups as a function of ANC test-positivity and potential covariates.; The relationship between ANC test-positivity and survey prevalence in children follows spatially and biologically meaningful patterns. However, the uncertainty of the relationship was substantial, particularly in areas with high or perennial transmission. In comparison, modelled data estimated higher prevalence in children at low transmission intensities and lower prevalence at higher transmission intensities.; Pregnant women attending ANC are a pragmatic sentinel population to assess heterogeneity and trends in malaria prevalence in Tanzania. Yet, since ANC malaria test-positivity cannot be used to directly predict the prevalence in other population subgroups, complementary community-level measurements remain highly relevant

    Технология сборки и сварки стропильной фермы

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    Цель работы заключается в разработке технологии сборки и сварки полигональных стропильных ферм и выполнении плана расстановки оборудования в производственном цеху. В результате выполнения выпускной квалификационной работы был определен перечень необходимых операций для производственного цикла, выбран способ сварки, а так же сварочное оборудование, материалы и приспособления, облегчающие сборку. Предложен план расстановки оборудования в производственном цеху. Проведен анализ конкурентоспособности, ресурсоэффективности предлагаемой технологии и анализ вредных и опасных факторов на производстве.The aim of the work is to develop a technology for assembling and welding polygonal rafters and implementing a plan for arranging equipment in the production hall. As a result of the final qualification work, a list of necessary operations for the production cycle was determined, a welding method, as well as welding equipment, materials and devices facilitating assembly was selected. A plan is proposed for arranging equipment in the production shop. The analysis of competitiveness, resource efficiency of the proposed technology and the analysis of harmful and dangerous factors in production are carried out

    Effectiveness of neonatal pulse oximetry screening for detection of critical congenital heart disease in daily clinical routine—results from a prospective multicenter study

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    Pulse oximetry screening (POS) has been proposed as an effective, noninvasive, inexpensive tool allowing earlier diagnosis of critical congenital heart disease (cCHD). Our aim was to test the hypothesis that POS can reduce the diagnostic gap in cCHD in daily clinical routine in the setting of tertiary, secondary and primary care centres. We conducted a prospective multicenter trial in Saxony, Germany. POS was performed in healthy term and post-term newborns at the age of 24–72 h. If an oxygen saturation (SpO2) of ≤95% was measured on lower extremities and confirmed after 1 h, complete clinical examination and echocardiography were performed. POS was defined as false-negative when a diagnosis of cCHD was made after POS in the participating hospitals/at our centre. From July 2006–June 2008, 42,240 newborns from 34 institutions have been included. Seventy-two children were excluded due to prenatal diagnosis (n = 54) or clinical signs of cCHD (n = 18) before POS. Seven hundred ninety-five newborns did not receive POS, mainly due to early discharge after birth (n = 727; 91%). In 41,445 newborns, POS was performed. POS was true positive in 14, false positive in 40, true negative in 41,384 and false negative in four children (three had been excluded for violation of study protocol). Sensitivity, specificity, positive and negative predictive value were 77.78%, 99.90%, 25.93% and 99.99%, respectively. With POS as an adjunct to prenatal diagnosis, physical examination and clinical observation, the percentage of newborns with late diagnosis of cCHD was 4.4%. POS can substantially reduce the postnatal diagnostic gap in cCHD, and false-positive results leading to unnecessary examinations of healthy newborns are rare. POS should be implemented in routine postnatal care

    First Search for Axion-Like Particles in a Storage Ring Using a Polarized Deuteron Beam

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    Based on the notion that the local dark-matter field of axions or axion-like particles (ALPs) in our Galaxy induces oscillating couplings to the spins of nucleons and nuclei (via the electric dipole moment of the latter and/or the paramagnetic axion-wind effect), we performed the first experiment to search for ALPs using a storage ring. For that purpose, we used an in-plane polarized deuteron beam stored at the Cooler Synchrotron COSY, scanning momenta near 970 MeV/c. This entailed a scan of the spin precession frequency. At resonance between the spin precession frequency of deuterons and the ALP-induced EDM oscillation frequency there will be an accumulation of the polarization component out of the ring plane. Since the axion frequency is unknown, the momentum of the beam and consequently the spin precession frequency were ramped to search for a vertical polarization change that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the axion/ALP field. A frequency window of 1.5-kHz width around the spin precession frequency of 121 kHz was scanned. We describe the experimental procedure and a test of the methodology with the help of a radiofrequency Wien filter located on the COSY ring. No ALP resonance was observed. As a consequence an upper limit of the oscillating EDM component of the deuteron as well as its axion coupling constants are provided.Comment: 25 pages, 24 figures, 7 tables, 67 reference
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