156 research outputs found

    Signal-to-noise ratio of temperature measurement with Cernox sensors at various supply currents

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    The Karlsruhe Institute of Technology (KIT) has developed a new thermal method for flow measurement, which is particularly suitable for the application in cryogenic systems. In this method, the stability and the resolution of temperature measurement is important, rather than precision. In other words, constant offsets in temperature measurements can be ignored, and the temperature sensors can be operated at supply currents beyond their nominal design value in order to gain resolution. For this application, the performance of two Cernox TM type CX-1050-SD-HT-1.4L sensors was measured in a temperature range between 300 K and 4 K. The experiments were carried out in the calibration cryostat at the Institute for Technical Physics. Sensors were connected to a Lake Shore Model 121 current source and a Keithley 2701/E digital multimeter for voltage measurements. At constant calibration temperatures, the supply currents were varied such that the resulting voltage drops lay in-between 10 mV and 100 mV. The influence on both the noise and the temperature offset are presented

    Literatur-Rundschau

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    Thomas Bohrmann/Werner Veith/Stephan Zöller (Hg.): Handbuch Theologie und Populärer Film (Benjamin Städter)Thomas Langkau: Filmstar Jesus Christus. Dieneuesten Jesus-Filme als Herausforderung für Theologie und Religionspädagogik (Peter Hasenberg)Julia Wippersberg: Prominenz. Entstehung, Erklärungen, Erwartungen (Ulrich Saxer)Kar! Josef Rivinius: Im Dienst der Mission und der Wissenschaft. Zur Entstehungsgeschichte der Zeitschrift Anthropos (Nicole Stroth)Urs Dahinden: Framing. Eine integrative Theorie der Massenkommunikation (Gerhard Vowe)Grit Kienzlen/Jan Lublinski/Volker Stollorz (Hg.): Fakt, Fiktion, Fälschung. Trends im Wissenschaftsjournalismus (Liane Rothenberger)Heinz-D. Fischer/Erika J. Fischer: Der Pulitzer-Preis. Konkurrenten, Kämpfe, Kontroversen (Joan Hemels)Achim Baum u. a. (Hg.): Handbuch Medienselbstkontrolle (Reiner Burger)

    Genetic deletion of the adaptor protein p66Shc increases susceptibility to short-term ischaemic myocardial injury via intracellular salvage pathways

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    Genetic deletion of p66Shc, as shown in the present study, leads to increased myocardial infarction in response to short-term ischaemia and reperfusion. Therefore, heart-specific activation of p66Shc protein may represent a promising novel strategy to prevent ischaemic and reperfusion myocardial injury. In particular, pharmacological modulation of apoptosis via myocardial salvage pathways involving p66Shc might be a promising approach to limit short-term ischaemic injury, for instance in patients with acute coronary syndrome (ACS) from the time of symptom onset to percutaneous coronary intervention. However, the present study also adds complexity to the use of this pathway as a therapeutic target. Indeed, given the different effects of activation and silencing of p66Shc in different cells, tissues and organs, tissue selective inhibition would be required. Indeed, while short-term activation might be protective in the context of an ACS, long-term inhibition may prevent endothelial dysfunction, atherosclerosis, and diabetic vascular disease. Obviously, this complexity also raises safety concerns for the potential use of p66Shc in acute myocardial infarction that need to be clarified by additional researc

    Protocol requirements and diagnostic value of PET/MR imaging for liver metastasis detection

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    Purpose: To compare the accuracy of PET/MR imaging with that of FDG PET/CT and to determine the MR sequences necessary for the detection of liver metastasis using a trimodality PET/CT/MR set-up. Methods: Included in this single-centre IRB-approved study were 55 patients (22 women, age 61 ± 11years) with suspected liver metastases from gastrointestinal cancer. Imaging using a trimodality PET/CT/MR set-up (time-of-flight PET/CT and 3-T whole-body MR imager) comprised PET, low-dose CT, contrast-enhanced (CE) CT of the abdomen, and MR with T1-W/T2-W, diffusion-weighted (DWI), and dynamic CE imaging. Two readers evaluated the following image sets for liver metastasis: PET/CT (set A), PET/CECT (B), PET/MR including T1-W/T2-W (C), T1-W/T2-W with either DWI (D) or CE imaging (E), and a combination (F). The accuracy of each image set was determined by receiver-operating characteristic analysis using image set B as the standard of reference. Results: Of 120 liver lesions in 21/55 patients (38%), 79 (66%) were considered malignant, and 63/79 (80%) showed abnormal FDG uptake. Accuracies were 0.937 (95% CI 89.5-97.9%) for image set A, 1.00 (95% CI 99.9-100.0%) for set C, 0.998 (95% CI 99.4-100.0%) for set D, 0.997 (95% CI 99.3-100.0%) for set E, and 0.995 (95% CI 99.0-100.0%) for set F. Differences were significant for image sets D-F (P < 0.05) when including lesions without abnormal FDG uptake. As shown by follow-up imaging after 50-177days, the use of image sets D and both sets E and F led to the detection of metastases in one and three patients, respectively, and further metastases in the contralateral lobe in two patients negative on PET/CECT (P = 0.06). Conclusion: PET/MR imaging with T1-W/T2-W sequences results in similar diagnostic accuracy for the detection of liver metastases to PET/CECT. To significantly improve the characterization of liver lesions, we recommend the use of dynamic CE imaging sequences. PET/MR imaging has a diagnostic impact on clinical decision making

    Counting and effective rigidity in algebra and geometry

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    The purpose of this article is to produce effective versions of some rigidity results in algebra and geometry. On the geometric side, we focus on the spectrum of primitive geodesic lengths (resp., complex lengths) for arithmetic hyperbolic 2-manifolds (resp., 3-manifolds). By work of Reid, this spectrum determines the commensurability class of the 2-manifold (resp., 3-manifold). We establish effective versions of these rigidity results by ensuring that, for two incommensurable arithmetic manifolds of bounded volume, the length sets (resp., the complex length sets) must disagree for a length that can be explicitly bounded as a function of volume. We also prove an effective version of a similar rigidity result established by the second author with Reid on a surface analog of the length spectrum for hyperbolic 3-manifolds. These effective results have corresponding algebraic analogs involving maximal subfields and quaternion subalgebras of quaternion algebras. To prove these effective rigidity results, we establish results on the asymptotic behavior of certain algebraic and geometric counting functions which are of independent interest.Comment: v.2, 39 pages. To appear in Invent. Mat

    A multi-decade record of high quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)

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    The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) “living data” publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID

    'Education, education, education' : legal, moral and clinical

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    This article brings together Professor Donald Nicolson's intellectual interest in professional legal ethics and his long-standing involvement with law clinics both as an advisor at the University of Cape Town and Director of the University of Bristol Law Clinic and the University of Strathclyde Law Clinic. In this article he looks at how legal education may help start this process of character development, arguing that the best means is through student involvement in voluntary law clinics. And here he builds upon his recent article which argues for voluntary, community service oriented law clinics over those which emphasise the education of students

    Comparison of intima-media thickness and ophthalmic artery resistance index for assessing subclinical atherosclerosis in HIV-1-infected patients

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    <p>Abstract</p> <p>Background</p> <p>Human immunodeficiency virus (HIV) infection and antiretroviral treatment are associated with metabolic and cardiovascular complications that potentially increase the risk of atherosclerosis and cardiovascular disease in this population. Measurement of arterial wall thickness has been used as a surrogate of extent, severity and progression of atherosclerosis. A cross-sectional cohort study was performed to compare the validity of two non-invasive arterial measures: carotid intima-media thickness (IMT), a parameter of atherosclerosis, and ophthalmic artery resistance index (OARI), an index of occlusive carotid artery disease.</p> <p>Methods</p> <p>A total of 95 patients receiving highly active antiretroviral therapy (HAART) for more than 12 months were consecutively enrolled. IMT and OARI were measured by 7.5 MHz linear probe.</p> <p>Results</p> <p>There was a significant linear increase in IMT and OARI values as the grade of cardiovascular risk (0.70 and 0.69 for very low risk, 0.86 and 0.72 for low risk and 0.98 and 0.74 for medium/high risk, p < 0.001). A IMT > 0.83 and an OARI > 0.72 were the most discriminatory values for predicting a cardiovascular risk ≥ 10% (sensibility 89.6% and 75.8%; sensitivity 70.5% and 68.4%; p < 0.001).</p> <p>Conclusions</p> <p>Our data indicate that OARI may have a potential as a new precocious marker of subclinical atherosclerosis in HIV-1-infected patients.</p

    Protocol requirements and diagnostic value of PET/MR imaging for liver metastasis detection

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    PURPOSE: To compare the accuracy of PET/MR imaging with that of FDG PET/CT and to determine the MR sequences necessary for the detection of liver metastasis using a trimodality PET/CT/MR set-up. METHODS: Included in this single-centre IRB-approved study were 55 patients (22 women, age 61 ± 11 years) with suspected liver metastases from gastrointestinal cancer. Imaging using a trimodality PET/CT/MR set-up (time-of-flight PET/CT and 3-T whole-body MR imager) comprised PET, low-dose CT, contrast-enhanced (CE) CT of the abdomen, and MR with T1-W/T2-W, diffusion-weighted (DWI), and dynamic CE imaging. Two readers evaluated the following image sets for liver metastasis: PET/CT (set A), PET/CECT (B), PET/MR including T1-W/T2-W (C), T1-W/T2-W with either DWI (D) or CE imaging (E), and a combination (F). The accuracy of each image set was determined by receiver-operating characteristic analysis using image set B as the standard of reference. RESULTS: Of 120 liver lesions in 21/55 patients (38 %), 79 (66 %) were considered malignant, and 63/79 (80 %) showed abnormal FDG uptake. Accuracies were 0.937 (95 % CI 89.5 - 97.9 %) for image set A, 1.00 (95 % CI 99.9 - 100.0 %) for set C, 0.998 (95 % CI 99.4 - 100.0 %) for set D, 0.997 (95 % CI 99.3 - 100.0 %) for set E, and 0.995 (95 % CI 99.0 - 100.0 %) for set F. Differences were significant for image sets D - F (P < 0.05) when including lesions without abnormal FDG uptake. As shown by follow-up imaging after 50 - 177 days, the use of image sets D and both sets E and F led to the detection of metastases in one and three patients, respectively, and further metastases in the contralateral lobe in two patients negative on PET/CECT (P = 0.06). CONCLUSION: PET/MR imaging with T1-W/T2-W sequences results in similar diagnostic accuracy for the detection of liver metastases to PET/CECT. To significantly improve the characterization of liver lesions, we recommend the use of dynamic CE imaging sequences. PET/MR imaging has a diagnostic impact on clinical decision making

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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