175 research outputs found

    A taxonomy of parallel sorting

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    TR 84-601In this paper, we propose a taxonomy of parallel sorting that includes a broad range of array and file sorting algorithms. We analyze the evolution of research on parallel sorting, from the earliest sorting networks to the shared memory algorithms and the VLSI sorters. In the context of sorting networks, we describe two fundamental parallel merging schemes - the odd-even and the bitonic merge. Sorting algorithms have been derived from these merging algorithms for parallel computers where processors communicate through interconnection networks such as the perfect shuffle, the mesh and a number of other sparse networks. After describing the network sorting algorithms, we show that, with a shared memory model of parallel computation, faster algorithms have been derived from parallel enumeration sorting schemes, where keys are first ranked and then rearranged according to their rank

    Adverse Events in Robotic Surgery: A Retrospective Study of 14 Years of FDA Data

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    Understanding the causes and patient impacts of surgical adverse events will help improve systems and operational practices to avoid incidents in the future. We analyzed the adverse events data related to robotic systems and instruments used in minimally invasive surgery, reported to the U.S. FDA MAUDE database from January 2000 to December 2013. We determined the number of events reported per procedure and per surgical specialty, the most common types of device malfunctions and their impact on patients, and the causes for catastrophic events such as major complications, patient injuries, and deaths. During the study period, 144 deaths (1.4% of the 10,624 reports), 1,391 patient injuries (13.1%), and 8,061 device malfunctions (75.9%) were reported. The numbers of injury and death events per procedure have stayed relatively constant since 2007 (mean = 83.4, 95% CI, 74.2-92.7). Surgical specialties, for which robots are extensively used, such as gynecology and urology, had lower number of injuries, deaths, and conversions per procedure than more complex surgeries, such as cardiothoracic and head and neck (106.3 vs. 232.9, Risk Ratio = 2.2, 95% CI, 1.9-2.6). Device and instrument malfunctions, such as falling of burnt/broken pieces of instruments into the patient (14.7%), electrical arcing of instruments (10.5%), unintended operation of instruments (8.6%), system errors (5%), and video/imaging problems (2.6%), constituted a major part of the reports. Device malfunctions impacted patients in terms of injuries or procedure interruptions. In 1,104 (10.4%) of the events, the procedure was interrupted to restart the system (3.1%), to convert the procedure to non-robotic techniques (7.3%), or to reschedule it to a later time (2.5%). Adoption of advanced techniques in design and operation of robotic surgical systems may reduce these preventable incidents in the future.Comment: Presented as the J. Maxwell Chamberlain Memorial Paper for adult cardiac surgery at the 50th Annual Meeting of the Society of Thoracic Surgeons in January. See Appendix for more detailed results, discussions, and related work. Updated the header

    Crystal Structures of (\u3cem\u3eZ\u3c/em\u3e)-5-[2-(benzo[\u3cem\u3eb\u3c/em\u3e]thiophen-2-yl)-1-(3,5-dimethoxyphenyl)ethenyl]-1\u3cem\u3eH\u3c/em\u3e-tetrazole and (\u3cem\u3eZ\u3c/em\u3e)-5-[2-(benzo[\u3cem\u3eb\u3c/em\u3e]thiophen-3-yl)-1-(3,4,5-trimethoxyphenyl)ethenyl]-1\u3cem\u3eH\u3c/em\u3e-tetrazole

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    (Z)-5-[2-(Benzo[b]thio­phen-2-yl)-1-(3,5-di­meth­oxy­phen­yl)ethen­yl]-1H-tetrazole methanol monosolvate, C19H16N4O2S·CH3OH, (I), was prepared by the reaction of (Z)-3-(benzo[b]thio­phen-2-yl)-2-(3,5-di­meth­oxy­phen­yl)acrylo­nitrile with tri­butyl­tin azide via a [3 + 2]cyclo­addition azide condensation reaction. The structurally related compound (Z)-5-[2-(benzo[b]thio­phen-3-yl)-1-(3,4,5-tri­meth­oxy­phen­yl)ethen­yl]-1H-tetra­zole, C20H18N4O3S, (II), was prepared by the reaction of (Z)-3-(benzo[b]thio­phen-3-yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylo­nitrile with tri­butyl­tin azide. Crystals of (I) have two mol­ecules in the asymmetric unit (Z′ = 2), whereas crystals of (II) have Z′ = 1. The benzo­thio­phene rings in (I) and (II) are almost planar, with r.m.s deviations from the mean plane of 0.0084 and 0.0037 Å in (I) and 0.0084 Å in (II). The tetra­zole rings of (I) and (II) make dihedral angles with the mean planes of the benzo­thio­phene rings of 88.81 (13) and 88.92 (13)° in (I), and 60.94 (6)° in (II). The di­meth­oxy­phenyl and tri­meth­oxy­phenyl rings make dihedral angles with the benzo­thio­phene rings of 23.91 (8) and 24.99 (8)° in (I) and 84.47 (3)° in (II). In both structures, mol­ecules are linked into hydrogen-bonded chains. In (I), these chains involve both tetra­zole and methanol, and are parallel to the b axis. In (II), mol­ecules are linked into chains parallel to the a axis by N—H⋯N hydrogen bonds between adjacent tetra­zole rings

    Detailed Bathymetric Surveys in the Central Indian Basin

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    Over 420,000 line kilometers of echo-sounding data was collected in the Central Indian Basin. This data was digitized, merged with navigation data and a detailed bathymetric map of the Basin was prepared. The Basin can be broadly classified into three regions as high relief area, medium relief area and plain area represented by western, eastern and central portions of the Basin, respectively. The bathymetric map prepared from this survey is the first of its kind for this region and will in the future be used as a base by navigators and researchers

    Evaluation of the antimicrobial activity of Gooseberry and Wild Apple fruit juices of the northeast region of India

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    A large number of wild fruits belonging to the North Eastern region of India are considered to be nutritionally abundant and traditionally used for the treatment of various ailments. In the present study, juices of Gooseberry and Wild Apple have been evaluated for their antimicrobial activity in its consumable form as a potential source of natural anti-infective agent. The fruit juices were screened for their antibacterial and antifungal activities qualitatively, using the agar well diffusion method followed by quantitative assessment by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The study revealed that both the fruit juices exhibited broad spectrum antibacterial activity. Considerable activity against drug resistant pathogens such as Methicillin Resistant Staphylococcus aureus (MRSA), Vancomycin Resistant Enterococci (VRE) and Extended Spectrum β-Lactamases (ESBL) producing Gram Negative bacteria (GNB) was observed. Thus, this study highlights the antibacterial efficacy of Wild Apple and Gooseberry fruit juices and augments the beneficiary properties of highly nutritional fruit juices that are specific to the Indian region

    A fractional K-BKZ constitutive formulation for describing the nonlinear rheology of multiscale complex fluids

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    The relaxation processes of a wide variety of soft materials frequently contain one or more broad regions of power-law like or stretched exponential relaxation in time and frequency. Fractional constitutive equations have been shown to be excellent models for capturing the linear viscoelastic behavior of such materials, and their relaxation modulus can be quantitatively described very generally in terms of a Mittag–Leffler function. However, these fractional constitutive models cannot describe the nonlinear behavior of such power-law materials. We use the example of Xanthan gum to show how predictions of nonlinear viscometric properties, such as shear-thinning in the viscosity and in the first normal stress coefficient, can be quantitatively described in terms a nonlinear fractional constitutive model. We adopt an integral K-BKZ framework and suitably modify it for power-law materials exhibiting Mittag–Leffler type relaxation dynamics at small strains. Only one additional parameter is needed to predict nonlinear rheology, which is introduced through an experimentally measured damping function. Empirical rules such as the Cox–Merz rule and Gleissle mirror relations are frequently used to estimate the nonlinear response of complex fluids from linear rheological data. We use the fractional model framework to assess the performance of such heuristic rules and quantify the systematic offsets, or shift factors, that can be observed between experimental data and the predicted nonlinear response. We also demonstrate how an appropriate choice of fractional constitutive model and damping function results in a nonlinear viscoelastic constitutive model that predicts a flow curve identical to the elastic Herschel-Bulkley model. This new constitutive equation satisfies the Rutgers-Delaware rule, which is appropriate for yielding materials. This K-BKZ framework can be used to generate canonical three-element mechanical models that provide nonlinear viscoelastic generalizations of other empirical inelastic models such as the Cross model. In addition to describing nonlinear viscometric responses, we are also able to provide accurate expressions for the linear viscoelastic behavior of complex materials that exhibit strongly shear-thinning Cross-type or Carreau-type flow curves. The findings in this work provide a coherent and quantitative way of translating between the linear and nonlinear rheology of multiscale materials, using a constitutive modeling approach that involves only a few material parameters

    Ligand-Induced Proton Transfer and Low-Barrier Hydrogen Bond Revealed by X-ray Crystallography

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    Ligand binding can change the pKa of protein residues and influence enzyme catalysis. Herein, we report three sub-Angstrom resolution X-ray crystal structures of CTX-M \u3b2-lactamase, representing three stages of the enzymatic pathway, apo protein (0.79 \uc5), pre-covalent complex (0.89 \uc5), and acylation transition state analog (0.84 \uc5). The binding of a non-covalent ligand induces a proton transfer from the catalytic Ser70 to the general base Glu166, and the formation of a low-barrier hydrogen bond (LBHB) between Ser70 and Lys73. QM/MM reaction path calculations determined the proton transfer barrier between Ser70 and Lys73 to be 1.53 kcal/mol, further confirming the presence of a LBHB. This LBHB is absent in the other two structures. Our data represents the first evidence of a direct and transient LBHB stabilizing a nucleophilic serine, as hypothesized by Cleland and Kreevoy. These results have important implications for the study of enzyme mechanisms as well as protein-inhibitor interactions

    Just married: the synergy between feminist criminology and the Tripartite Cybercrime Framework

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    This article is a theoretical treatment of feminist epistemology of crime, which advocates the centrality of gender as a theoretical starting point for the investigating of digital crimes. It does so by exploring the synergy between the feminist perspectives and the Tripartite Cybercrime Framework (TCF) (which argues that three possible factors motivate cybercrimes – socioeconomic, psychosocial, and geopolitical) to critique mainstream criminology and the meaning of the term “cybercrime”. Additionally, the article examines gender gaps in online harassment, cyber‐bullying, cyber‐fraud, revenge porn, and cyber‐stalking to demonstrate that who is victimised, why, and to what effect are the critical starting points for the analysis of the connections between gender and crimes. In turn, it uses the lens of intersectionality to acknowledge that, while conceptions of gender and crime interact, they intersect with other categories (e.g., sexuality) to provide additional layers of explanation. To nuance the utilitarian value of the synergy between the TCF and the feminist perspectives, the focus shifts to a recent case study (which compared socioeconomic and psychosocial cybercrimes). The article concludes that, while online and offline lives are inextricably intertwined, the victimisations in psychosocial cybercrimes may be more gendered than in socioeconomic cybercrimes. These contributions align the TCF to the feminist epistemology of crime in their attempt to move gender analysis of digital crimes “from margin to centre”
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