1,050 research outputs found

    Dissipation of the 3^He A-B Transition

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    A rigorous hydrodynamic theory of the A-B transition is presented. All dissipative processes are considered. At low interface velocities, those occurring on hydrodynamic length scales, not considered hitherto, are most probably the dominant ones.Comment: 13 pages, REVTeX, 2 figures, ITP-UH 13/9

    Bubble Growth in Superfluid 3-He: The Dynamics of the Curved A-B Interface

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    We study the hydrodynamics of the A-B interface with finite curvature. The interface tension is shown to enhance both the transition velocity and the amplitudes of second sound. In addition, the magnetic signals emitted by the growing bubble are calculated, and the interaction between many growing bubbles is considered.Comment: 20 pages, 3 figures, LaTeX, ITP-UH 11/9

    The Patient in Patient Safety: Clinicians’ Experiences Engaging Patients as Partners in Safety

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    Patients and families play a role in the safety of care provided across clinical settings, highlighting the need to understand clinician perspectives and experiences related to their engagement. Through a panel discussion entitled, The Patient in Patient Safety: Clinicians’ Experiences Engaging Patients as Partners in Safety, we elicited clinician perspectives that have implications for human factors relevance in both, research and solution development/evaluation. We provide an overview of the panel including participants, format and content, and the resulting discussion

    The ALICE Data Challenges

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    Since 1998, the ALICE experiment and the CERN/IT division have jointly executed several large-scale high throughput distributed computing exercises: the ALICE data challenges. The goals of these regular exercises are to test hardware and software components of the data acquisition and computing systems in realistic conditions and to execute an early integration of the overall ALICE computing infrastructure. This paper reports on the third ALICE Data Challenge (ADC III) that has been performed at CERN from January to March 2001. The data used during the ADC III are simulated physics raw data of the ALICE TPC, produced with the ALICE simulation program AliRoot. The data acquisition was based on the ALICE online framework called the ALICE Data Acquisition Test Environment (DATE) system. The data after event building were then formatted with the ROOT I/O package and a data catalogue based on MySQL was established. The Mass Storage System used during ADC III is CASTOR. Different software tools have been used to monitor the performances. DATE has demonstrated performances of more than 500 MByte/s. An aggregate data throughput of 85 MByte/s was sustained in CASTOR over several days. The total collected data amounts to 100 TBytes in 100,000 files

    Variants Within TSC2 Exons 25 and 31 Are Very Unlikely to Cause Clinically Diagnosable Tuberous Sclerosis

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    Inactivating mutations in TSC1 and TSC2 cause tuberous sclerosis complex (TSC). The 2012 international consensus meeting on TSC diagnosis and management agreed that the identification of a pathogenic TSC1 or TSC2 variant establishes a diagnosis of TSC, even in the absence of clinical signs. However, exons 25 and 31 of TSC2 are subject to alternative splicing. No variants causing clinically diagnosed TSC have been reported in these exons, raising the possibility that such variants would not cause TSC. We present truncating and in‐frame variants in exons 25 and 31 in three individuals unlikely to fulfil TSC diagnostic criteria and examine the importance of these exons in TSC using different approaches. Amino acid conservation analysis suggests significantly less conservation in these exons compared with the majority of TSC2 exons, and TSC2 expression data demonstrates that the majority of TSC2 transcripts lack exons 25 and/or 31 in many human adult tissues. In vitro assay of both exons shows that neither exon is essential for TSC complex function. Our evidence suggests that variants in TSC2 exons 25 or 31 are very unlikely to cause classical TSC, although a role for these exons in tissue/stage specific development cannot be excluded

    Synthesis and Characterization of Cobalt(II) N,Nâ€Č‑Diphenylazodioxide Complexes

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    Removal of chloride from CoCl2 with TlPF6 in acetonitrile, followed by addition of excess nitrosobenzene, yielded the eight-coordinate cobalt(II) complex salt [Co{Ph(O)NN(O)- Ph}4](PF6)2, shown by single-crystal X-ray analysis to have a distorted tetragonal geometry. The analogous treatment of the bipyridyl complex Co(bpy)Cl2 yielded the mixed-ligand cobalt(II) complex salt [Co(bpy){Ph(O)NN(O)Ph}2](PF6)2, whose singlecrystal X-ray structure displays a trigonal prismatic geometry, similar to that of the iron(II) cation in the previously known complex salt [Fe{Ph(O)NN(O)Ph}3](FeCl4)2. The use of TlPF6 to generate solvated metal complex cations from chloride salts or chlorido complexes, followed by the addition of nitrosobenzene, is shown to be a useful synthetic strategy for the preparation of azodioxide complex cations with the noncoordinating, diamagnetic PF6 − counteranion. Coordination number appears to be more important than d electron count in determining the geometry and metal−ligand bond distances of diphenylazodioxide complexes

    Annual Greenland accumulation rates (2009–2012) from airborne snow radar

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    Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor its surface mass balance in order to improve sea-level rise predictions. Snow accumulation is the largest component of the ice sheet's surface mass balance, but in situ observations thereof are inherently sparse and models are difficult to evaluate at large scales. Here, we quantify recent Greenland accumulation rates using ultra-wideband (2–6.5 GHz) airborne snow radar data collected as part of NASA's Operation IceBridge between 2009 and 2012. We use a semiautomated method to trace the observed radiostratigraphy and then derive annual net accumulation rates for 2009–2012. The uncertainty in these radar-derived accumulation rates is on average 14 %. A comparison of the radar-derived accumulation rates and contemporaneous ice cores shows that snow radar captures both the annual and long-term mean accumulation rate accurately. A comparison with outputs from a regional climate model (MAR) shows that this model matches radar-derived accumulation rates in the ice sheet interior but produces higher values over southeastern Greenland. Our results demonstrate that snow radar can efficiently and accurately map patterns of snow accumulation across an ice sheet and that it is valuable for evaluating the accuracy of surface mass balance models
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