420 research outputs found

    Traveling-Wave Tubes

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    Contains reports on two research projects

    CERAD und NOSGER: Der prädiktive Wert dieser Verfahren in der Demenzdiagnostik einer Schweizer gerontopsychiatrischen Patientenpopulation

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    Zusammenfassung: Hintergrund: Die CERAD-Batterie (Consortium to Establish a Registry for Alzheimer's Disease) ist ein gängiges Screeninginstrument in der Diagnostik der Alzheimer-Demenz. Dem NOSGER (Nurses Observation' Scale for Geriatric Patients), eigentlich entwickelt, um Verhaltensauffälligkeiten im Alltag zu erfassen, scheint bei der Alzheimer-Demenz auch eine diagnostische Bedeutung zuzukommen. Material und Methode: In einer retrospektiven Studie mit 400 Patienten unserer Klinik, die bei unterschiedlichen psychiatrischen Erkrankungen kognitive Störungen aufwiesen, haben wir CERAD und NOSGER mittels logistischer Berechnung in uni- und multivariaten Modellen auf ihren prädiktiven Wert für die Diagnose Demenz untersucht. Ergebnisse: Im univariaten Modell waren alle CERAD-Subtests signifikante Prädiktoren für Demenz. Das beste multivariate Modell umfasste die Subtests "Verbale Flüssigkeit", "Wortliste Abrufen", "Konstruktive Praxie Abrufen" und MMS (Mini-Mental Status). Der NOSGER zeigte keinen prädiktiven diagnostischen Wert. Schlussfolgerung: Innerhalb einer gerontopsychiatrischen Population grenzt der CERAD Demenzpatienten von nicht dementen mit hoher Vorhersagewahrscheinlichkeit ab, während der NOSGER keinen prädiktiven Wert für die Diagnose Demenz aufweis

    Rapid tests and urine sampling techniques for the diagnosis of urinary tract infection (UTI) in children under five years: a systematic review

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    Background: Urinary tract infection (UTI) is one of the most common sources of infection in children under five. Prompt diagnosis and treatment is important to reduce the risk of renal scarring. Rapid, cost-effective, methods of UTI diagnosis are required as an alternative to culture. Methods: We conducted a systematic review to determine the diagnostic accuracy of rapid tests for detecting UTI in children under five years of age. Results: The evidence supports the use of dipstick positive for both leukocyte esterase and nitrite (pooled LR+ = 28.2, 95% CI: 17.3, 46.0) or microscopy positive for both pyuria and bacteriuria (pooled LR+ = 37.0, 95% CI: 11.0, 125.9) to rule in UTI. Similarly dipstick negative for both LE and nitrite (Pooled LR- = 0.20, 95% CI: 0.16, 0.26) or microscopy negative for both pyuria and bacteriuria (Pooled LR- = 0.11, 95% CI: 0.05, 0.23) can be used to rule out UTI. A test for glucose showed promise in potty-trained children. However, all studies were over 30 years old. Further evaluation of this test may be useful. Conclusion: Dipstick negative for both LE and nitrite or microscopic analysis negative for both pyuria and bacteriuria of a clean voided urine, bag, or nappy/pad specimen may reasonably be used to rule out UTI. These patients can then reasonably be excluded from further investigation, without the need for confirmatory culture. Similarly, combinations of positive tests could be used to rule in UTI, and trigger further investigation

    Institutional Pressures and Organizational Identity: The Case of Deutsche Werkstätten Hellerau in the GDR and Beyond, 1945-1996

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    This article explores the case of Deutsche Werkstätten Hellerau (DWH) - a furniture and interior manufacturer founded in 1898 - through state socialism after 1945 and reprivatization in the 1990s. Our analysis suggests that the firm's survival through multiple systemic disruptions was partly due to the preservation of a unique identity despite heavy institutional pressures for conformity. DWH adopted a "mixed conformity" strategy that attempted to pitch multiple concerns (cultural-aesthetic, ideological, economic) of political authorities against one another to buffer sociopolitical pressures, thus ultimately conforming to some (identity-consistent) demands, while violating other (identity-threatening) ones. This allowed DWH to successfully navigate tensions between sociopolitical expectations and the need to preserve a collective sense of distinctiveness and continuity over time

    How does study quality affect the results of a diagnostic meta-analysis?

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    Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited

    Common Genetic Variation at the IL1RL1 Locus Regulates IL-33/ST2 Signaling

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    The suppression of tumorigenicity 2/IL-33 (ST2/IL-33) pathway has been implicated in several immune and inflammatory diseases. ST2 is produced as 2 isoforms. The membrane-bound isoform (ST2L) induces an immune response when bound to its ligand, IL-33. The other isoform is a soluble protein (sST2) that is thought to be a decoy receptor for IL-33 signaling. Elevated sST2 levels in serum are associated with an increased risk for cardiovascular disease. We investigated the determinants of sST2 plasma concentrations in 2,991 Framingham Offspring Cohort participants. While clinical and environmental factors explained some variation in sST2 levels, much of the variation in sST2 production was driven by genetic factors. In a genome-wide association study (GWAS), multiple SNPs within IL1RL1 (the gene encoding ST2) demonstrated associations with sST2 concentrations. Five missense variants of IL1RL1 correlated with higher sST2 levels in the GWAS and mapped to the intracellular domain of ST2, which is absent in sST2. In a cell culture model, IL1RL1 missense variants increased sST2 expression by inducing IL-33 expression and enhancing IL-33 responsiveness (via ST2L). Our data suggest that genetic variation in IL1RL1 can result in increased levels of sST2 and alter immune and inflammatory signaling through the ST2/IL-33 pathway.Stem Cell and Regenerative Biolog

    Optical implementation of a unitarily correctable code

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    Noise poses a challenge for any real-world implementation in quantum information science. The theory of quantum error correction deals with this problem via methods to encode and recover quantum information in a way that is resilient against that noise. Unitarily correctable codes are an error correction technique wherein a single unitary recovery operation is applied without the need for an ancilla Hilbert space. Here, we present the first optical implementation of a non-trivial unitarily correctable code for a noisy quantum channel with no decoherence-free subspaces or noiseless subsystems. We show that recovery of our initial states is achieved with high fidelity (>=0.97), quantitatively proving the efficacy of this unitarily correctable code.Comment: 6 pages, 3 figure

    Mitigation of ionospheric signatures in Swarm GPS gravity field estimation using weighting strategies

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    Even though ESA's three-satellite low-earth orbit (LEO) mission Swarm is primarily a magnetic field mission, it can also serve as a gravity field mission. Located in a near-polar orbit with initial altitudes of 480&thinsp;km for Swarm A and Swarm C and 530&thinsp;km for Swarm B and equipped with geodetic-type dual frequency Global Positioning System (GPS) receivers, it is suitable for gravity field computation. Of course, the Swarm GPS-only gravity fields cannot compete with the gravity fields derived from the ultra-precise Gravity Recovery And Climate Experiment (GRACE) K-band measurements. But for various reasons like the end of the GRACE mission in October 2017, data gaps in the previous months due to battery aging, and the gap between GRACE and the recently launched GRACE Follow-On mission, Swarm gravity fields became important to maintain a continuous time series and to bridge the gap between the two dedicated gravity missions. By comparing the gravity fields derived from Swarm kinematic positions to the GRACE gravity fields, systematic errors have been observed in the Swarm results, especially around the geomagnetic equator. These errors are already visible in the kinematic positions as spikes up to a few centimeters, from where they propagate into the gravity field solutions. We investigate these systematic errors by analyzing the geometry-free linear combination of the GPS carrier-phase observations and its time derivatives using a combination of a Gaussian filter and a Savitzky–Golay filter and the Rate of Total Electron Content (TEC) Index (ROTI). Based on this, we present different weighting schemes and investigate their impact on the gravity field solutions in order to assess the success of different mitigation strategies. We will show that a combination of a derivative-based weighting approach with a ROTI-based weighting approach is capable of reducing the geoid rms from 21.6 to 12.0&thinsp;mm for a heavily affected month and that almost 10&thinsp;% more kinematic positions can be preserved compared to a derivative-based screening.</p
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