1,152 research outputs found

    An improved Monte Carlo method for direct calculation of the density of states

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    We present an efficient Monte Carlo algorithm for determining the density of states which is based on the statistics of transition probabilities between states. By measuring the infinite temperature transition probabilities--that is, the probabilities associated with move proposal only--we are able to extract excellent estimates of the density of states. When this estimator is used in conjunction with a Wang-Landau sampling scheme [F. Wang and D. P. Landau, Phys. Rev. Lett. 86, 2050 (2001)], we quickly achieve uniform sampling of macrostates (e.g., energies) and systematically refine the calculated density of states. This approach requires only potential energy evaluations, continues to improve the statistical quality of its results as the simulation time is extended, and is applicable to both lattice and continuum systems. We test the algorithm on the Lennard-Jones liquid and demonstrate good statistical convergence properties.Comment: 7 pages, 4 figures. to appear in Journal of Chemical Physic

    The Role of Bargaining Style in Public Company Audits

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    According to prior auditing research, negotiation plans an important role in audit outcomes. General purpose negotiating literature suggests that bargaining styles are an important factor in business negotiations and that bargaining style mismatches between negotiating counter-parties can influence negotiation results. To date, the role of auditors\u27 bargaining-style tendencies in audit negotiations has gone unnoticed in the auditing literature. A study examines the bargaining styles of accountants and managers as measured by the Thomas-Kilmann Conflict Mode Instrument. The results suggest that accountants are predisposed to avoid conflict or accommodate whereas managers are predisposed to collaborate or compete. Recognizing this potential mismatch of bargaining styles should help the auditor to develop more effective negotiation strategies

    Even faster sorting of (not only) integers

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    In this paper we introduce RADULS2, the fastest parallel sorter based on radix algorithm. It is optimized to process huge amounts of data making use of modern multicore CPUs. The main novelties include: extremely optimized algorithm for handling tiny arrays (up to about a hundred of records) that could appear even billions times as subproblems to handle and improved processing of larger subarrays with better use of non-temporal memory stores

    New instrumentation technologies for testing the bonding of sensors to solid materials

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    This report presents the results of a comprehensive research and development project that was conducted over a three-year period to develop new technologies for testing the attachment of sensors to solid materials for the following NASA applications: (1) testing the performance of composites that are used for the lining of solid rocket motor nozzles, (2) testing the bonding of surface-mounted platinum resistance thermometers that are used on fuel and oxidizer lines of the space shuttle to detect valve leaks by monitoring temperature, (3) testing the attachment of strain gages that are used in testing the performance of space shuttle main engines, and (4) testing the thermocouples that are used for determining the performance of blast tube liner material in solid rocket boosters

    Influence of Peer Pressure and Self-Efficacy for Alcohol Self-Regulation on Chinese University Physical Education Students’ Drinking Behaviors

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    This study examined peer group influence on university student drinking in China and the indirect effects of peer pressure and self-efficacy for alcohol self-regulation. A total of 951 undergraduate university students (first, second and third year) from a university in central China completed questionnaires asking about perceived peer pressures, self-efficacy for alcohol self-regulation, and drinking frequency. Analysis of their answers showed that the drinking frequency among physical education (PE) students was higher than among the comparison group (History students). The PE students perceived greater peer pressure, and had lower self-efficacy for alcohol self-regulation, both of which contributed directly to drinking frequency. Path analysis indicated indirect effects of peer pressure and self-efficacy for alcohol self-regulation on the association between peer group membership and drinking frequency. This suggested that skills training to increase self-efficacy for alcohol self-regulation in culturally-specific settings have the potential to both directly and indirectly lower drinking rates in peer groups with high peer pressure and higher than normal drinking

    Defining the Transcriptional and Post-transcriptional Landscapes of Mycobacterium smegmatis in Aerobic Growth and Hypoxia

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    The ability of Mycobacterium tuberculosis to infect, proliferate, and survive during long periods in the human lungs largely depends on the rigorous control of gene expression. Transcriptome-wide analyses are key to understanding gene regulation on a global scale. Here, we combine 5′-end-directed libraries with RNAseq expression libraries to gain insight into the transcriptome organization and post-transcriptional mRNA cleavage landscape in mycobacteria during log phase growth and under hypoxia, a physiologically relevant stress condition. Using the model organism Mycobacterium smegmatis, we identified 6,090 transcription start sites (TSSs) with high confidence during log phase growth, of which 67% were categorized as primary TSSs for annotated genes, and the remaining were classified as internal, antisense, or orphan, according to their genomic context. Interestingly, over 25% of the RNA transcripts lack a leader sequence, and of the coding sequences that do have leaders, 53% lack a strong consensus Shine-Dalgarno site. This indicates that like M. tuberculosis, M. smegmatis can initiate translation through multiple mechanisms. Our approach also allowed us to identify over 3,000 RNA cleavage sites, which occur at a novel sequence motif. To our knowledge, this represents the first report of a transcriptome-wide RNA cleavage site map in mycobacteria. The cleavage sites show a positional bias toward mRNA regulatory regions, highlighting the importance of post-transcriptional regulation in gene expression. We show that in low oxygen, a condition associated with the host environment during infection, mycobacteria change their transcriptomic profiles and endonucleolytic RNA cleavage is markedly reduced, suggesting a mechanistic explanation for previous reports of increased mRNA half-lives in response to stress. In addition, a number of TSSs were triggered in hypoxia, 56 of which contain the binding motif for the sigma factor SigF in their promoter regions. This suggests that SigF makes direct contributions to transcriptomic remodeling in hypoxia-challenged mycobacteria. Taken together, our data provide a foundation for further study of both transcriptional and posttranscriptional regulation in mycobacteria

    A test of non-equilibrium thermodynamics in glassy systems: the soft-sphere case

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    The scaling properties of the soft-sphere potential allow the derivation of an exact expression for the pressure of a frozen liquid, i.e., the pressure corresponding to configurations which are local minima in its multidimensional potential energy landscape. The existence of such a relation offers the unique possibility for testing the recently proposed extension of the liquid free energy to glassy out-of-equilibrium conditions and the associated expression for the temperature of the configurational degrees of freedom. We demonstrate that the non-equilibrium free energy provides an exact description of the soft-sphere pressure in glass states

    Coordinated Multiple Cadaver Use for Minimally Invasive Surgical Training

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    BackgroundThe human cadaver remains the gold standard for anatomic training and is highly useful when incorporated into minimally invasive surgical training programs. However, this valuable resource is often not used to its full potential due to a lack of multidisciplinary cooperation. Herein, we propose the coordinated multiple use of individual cadavers to better utilize anatomical resources and potentiate the availability of cadaver training.MethodsTwenty-two postgraduate surgeons participated in a robot-assisted surgical training course that utilized shared cadavers. All participants completed a Likert 4-scale satisfaction questionnaire after their training session. Cadaveric tissue quality and the quality of the training session related to this material were assessed.ResultsNine participants rated the quality of the cadaveric tissue as excellent, 7 as good, 5 as unsatisfactory, and 1 as poor. Overall, 72% of participants who operated on a previously used cadaver were satisfied with their training experience and did not perceive the previous use deleterious to their training.ConclusionThe coordinated use of cadavers, which allows for multiple cadaver use for different teaching sessions, is an excellent training method that increases availability of human anatomical material for minimally invasive surgical training

    Energy landscapes, ideal glasses, and their equation of state

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    Using the inherent structure formalism originally proposed by Stillinger and Weber [Phys. Rev. A 25, 978 (1982)], we generalize the thermodynamics of an energy landscape that has an ideal glass transition and derive the consequences for its equation of state. In doing so, we identify a separation of configurational and vibrational contributions to the pressure that corresponds with simulation studies performed in the inherent structure formalism. We develop an elementary model of landscapes appropriate to simple liquids which is based on the scaling properties of the soft-sphere potential complemented with a mean-field attraction. The resulting equation of state provides an accurate representation of simulation data for the Lennard-Jones fluid, suggesting the usefulness of a landscape-based formulation of supercooled liquid thermodynamics. Finally, we consider the implications of both the general theory and the model with respect to the so-called Sastry density and the ideal glass transition. Our analysis shows that a quantitative connection can be made between properties of the landscape and a simulation-determined Sastry density, and it emphasizes the distinction between an ideal glass transition and a Kauzmann equal-entropy condition.Comment: 11 pages, 3 figure
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