194 research outputs found

    Evidence for Magnetic Field Induced Changes of the Phase of Tunneling States: Spontaneous Echoes in (KBr)1−x_{1-x}(KCN)x_x in Magnetic Fields

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    Recently, it has been discovered that in contrast to expectations the low-temperature dielectric properties of some multi-component glasses depend strongly on magnetic fields. In particular, the low-frequency dielectric susceptibility and the amplitude of coherent polarization echoes show striking non-monotonic magnetic field dependencies. The low-temperature dielectric response of these materials is governed by atomic tunneling systems. We now have investigated the coherent properties of tunneling states in a crystalline host in magnetic fields up to 230 mT. Two-pulse echo experiments have been performed on a KBr crystal containing about 7.5% CN−^-. Like in glasses, but perhaps even more surprising in the case of a crystalline system, we observe a very strong magnetic field dependence of the echo amplitude. Moreover, for the first time we have direct evidence that magnetic fields change the phase of coherent tunneling systems in a well-defined way. We present the data and discuss the possible origin of this intriguing effect.Comment: 4 pages, 3 figures, submitted to PR

    DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) OF THE SPINE: A CAUSE OF BACK PAIN? A CONTROLLED STUDY

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    This is the first controlled study of the frequency of back pain in a European caucasian population with diffuse idiopathic skeletal hyperostosis (DISH). Elderly patients admitted to hospital for reasons other than back pain were assessed for the presence of spinal DISH using the routine lateral chest radiograph films. A total of 106 probands (82 males, 24 females) with a mean age of 70 years fulfilled the criteria for DISH as defined previously. One hundred and seventyeight patients (117 males, 61 females) not meeting these criteria were used as controls. The prevalence of back pain was assessed by a blinded interviewer using a structured questionnaire. Our primary hymthesis was that spinal DISH positive probands had not had back pain more often than controls. The controlled study showed no statistically significant difference in pain frequency between spinal DISH positive probands and controls at any spinal level. We conclude that back pain does not occur more often in radiographically defined DISH positive probands than in controls. The radiological finding of spinal DISH, as far as it does not lead to stenosis of the spinal canal or dysphagia, thus seems to be a finding without clinical relevanc

    THE PREVALENCE OF PALPABLE FINGER JOINT NODULES IN DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH). A CONTROLLED STUDY

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    The presence of clinically palpable finger joint nodules a(Heberden's and Bouchard's nodes) was documented in 123 consecutive cases with diffuse idiopathic skeletal hyperostosis (DISH) of the thoracic spine and 191 matched DISH negative controls. The prevalence of palpable finger joint nodules was almost twice as frequent in cases with spinal DISH compared to controls (46% versus 31%, X2 = 7.67, P<0.01; multivariate adjusted odds ratio OR = 1.84; 95% CI: 1.14-2.98). This increase was most marked at the proximal interphalangeal joint, in males and in patients up to the age of 65 years. In addition and independent of other variables such as hyperostotic features, age and sex, the prevalence of palpable finger joint nodules was about twice as high in probands with a history of physically heavy work compared to those without (43% ver sus 26%, X = 9.18, P<0.005; multivariate adjusted odds ratio OR = 2.10; 95% CI: 1.26-3.52). From these results we con clude that DISH should be considered as an independent risk factor in the development of finger joint nodule

    Bio-Inspired Multi-Layer Spiking Neural Network Extracts Discriminative Features from Speech Signals

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    Spiking neural networks (SNNs) enable power-efficient implementations due to their sparse, spike-based coding scheme. This paper develops a bio-inspired SNN that uses unsupervised learning to extract discriminative features from speech signals, which can subsequently be used in a classifier. The architecture consists of a spiking convolutional/pooling layer followed by a fully connected spiking layer for feature discovery. The convolutional layer of leaky, integrate-and-fire (LIF) neurons represents primary acoustic features. The fully connected layer is equipped with a probabilistic spike-timing-dependent plasticity learning rule. This layer represents the discriminative features through probabilistic, LIF neurons. To assess the discriminative power of the learned features, they are used in a hidden Markov model (HMM) for spoken digit recognition. The experimental results show performance above 96% that compares favorably with popular statistical feature extraction methods. Our results provide a novel demonstration of unsupervised feature acquisition in an SNN

    DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) OF THE SHOULDER: A CAUSE OF SHOULDER PAIN?

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    Shoulder pain is a common complaint and shoulder hyperostosis a frequent radiological condition. However, little is known about the association between the clinical and radiological findings. To evaluate the clinical relevance of shoulder hyperostosis we performed a controlled, blind study of 99 hospitalized probands with and without thoracospinal hyperostosis on lateral chest X-rays. The study included grading of the shoulder hyperostosis on the basis of three bilateral standard radiographs, assessing shoulder pain in a standardized way by an interviewer and recording extraskeletal causes of shoulder pain. The prevalence of shoulder hyperostosis was doubled in probands with thoracospinal hyperostosis compared to controls (X2= 5.90, F>0.025, n = 99). Shoulder hyperostosis, irrespective of thoracospinal hyperostosis, predisposed to shoulder pain (40% versus 18%, x2 = 4.06, F>0.05, n = 74). Shoulder hyperostosis in combination with thoracospinal hyperostosis (shoulder DISH) predisposed to shoulder pain to an even greater extent (46% versus 12%, x2 = 6.64, P>0.01, n = 47). We conclude that shoulder hyperostosis is a radiological finding of potential clinical relevanc

    DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) OF THE ELBOW: A CAUSE OF ELBOW PAIN? A CONTROLLED STUDY

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    Elbow pain is a common complaint and elbow hyperostosis a frequent radiological condition. However, little is known about the association between the clinical and radiological findings. To evaluate the relationship between spinal and extraspinal hyperostotic features and the clinical relevance of elbow hyperostosis we have performed the first controlled, double-blinded study of 85 hospitalized probands, 33 with and 52 without thoracospinal hyperostosis on lateral chest X-ray. Elbow and shoulder hyperostosis were graded on bilateral standard radiographs. Elbow pain was assessed by an interviewer using a standardized questionnaire and extraskeletal causes of elbow pain were recorded. The prevalence of elbow hyperostosis was increased in cases with thoracospinal hyperostosis compared to controls (82% versus 58%, X2 = 5.32, P<0.025, n = 85, odds ratio (OR) 3.30 (95% Cl 1.16-9.35)). Similarly, the prevalence of elbow hyperostosis was increased in cases with shoulder hyperostosis compared to controls (83% versus 60%, x2 = 4.51, P<0.05, n = 84, OR = 3.20 (95% CI 1.06-9.66)), emphasizing the multifocal nature of hyperostotic features. Elbow pain was only slightly more prevalent in cases with elbow hyperostosis compared to controls (21% versus l3%, x2 = 0.75, NS, OR = 1.84 (95% CI 0.46-7.44)). We conclude that elbow hyperostosis is a radiological finding of doubtful clinical relevanc

    Temozolomide plus pegylated interferon alfa-2b as first-line treatment for stage IV melanoma: a multicenter phase II trial of the Dermatologic Cooperative Oncology Group (DeCOG)

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    Background: Combination of temozolomide (TMZ) with nonpegylated interferon alfa is associated with increased efficacy in terms of response rates compared with monotherapy. A multicenter phase II study was carried out to assess the activity and toxicity of TMZ plus pegylated interferon alfa-2b (peg-IFNα-2b), hypothesizing improved efficacy due to modified pharmacokinetic properties of the novel interferon (IFN) formulation. Patients and methods: In all, 124 patients with stage IV melanoma without prior chemotherapy and no cerebral metastases were treated with 100 μg peg-IFNα-2b s.c. per week and oral TMZ 200 mg/m2 (days 1-5, every 28 days). Primary study end point was objective response, and secondary end points were overall and progression-free survival (PFS) and safety. Results: In all, 116 patients were assessable for response: 2 (1.7%) had a complete response and 19 (16.4%) a partial response (overall response rate 18.1%). Of total, 25.0% achieved disease stabilization and 56.9% progressed. Overall survival was 9.4 months; PFS was 2.8 months. Grade 3/4 thrombocytopenia occurred in 20.7% and grade 3/4 leukopenia in 23.3%. Conclusions: The efficacy of TMZ plus peg-IFNα-2b in this large phase II study is moderate and comparable to published results of the combination of TMZ with non-peg-IFN. Likewise, the safety profile of peg-IFNα-2b seems to be similar to non-peg-IFN when combined with TM

    Why do women choose private over public facilities for family planning services? A qualitative study of post-partum women in an informal urban settlement in Kenya

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    BACKGROUND: Nearly 40 % of women in developing countries seek contraceptives services from the private sector. However, the reasons that contraceptive clients choose private or public providers are not well studied. METHODS: We conducted six focus groups discussions and 51 in-depth interviews with postpartum women (n = 61) to explore decision-making about contraceptive use after delivery, including facility choice. RESULTS: When seeking contraceptive services, women in this study preferred private over public facilities due to convenience and timeliness of services. Women avoided public facilities due to long waits and disrespectful providers. Study participants reported, however, that they felt more confident about the technical medical quality in public facilities than in private, and believed that private providers prioritized profit over safe medical practice. Women reported that public facilities offered comprehensive counseling and chose these facilities when they needed contraceptive decision-support. Provision of comprehensive counseling and screening, including side effects counseling and management, determined perception of quality. CONCLUSION: Women believed private providers offered the advantages of convenience, efficiency and privacy, though they did not consistently offer high-quality care. Quality-improvement of contraceptive care at private facilities could include technical standardization and accreditation. Development of support and training for side effect management may be an important intervention to improve perceived quality of care
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