325 research outputs found

    Fluctuating pressures measured beneath a high-temperature, turbulent boundary layer on a flat plate at Mach number of 5

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    Fluctuating pressures were measured beneath a Mach 5, turbulent boundary layer on a flat plate with an array of piezoresistive sensors. The data were obtained with a digital signal acquisition system during a test run of 4 seconds. Data sampling rate was such that frequency analysis up to 62.5 kHz could be performed. To assess in situ frequency response of the sensors, a specially designed waveguide calibration system was employed to measure transfer functions of all sensors and related instrumentation. Pressure time histories were approximated well by a Gaussian prohibiting distribution. Pressure spectra were very repeatable over the array span of 76 mm. Total rms pressures ranged from 0.0017 to 0.0046 of the freestream dynamic pressure. Streamwise, space-time correlations exhibited expected decaying behavior of a turbulence generated pressure field. Average convection speed was 0.87 of freestream velocity. The trendless behavior with sensor separation indicated possible systematic errors

    Fibercomposite and steel pavement dowels

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    Life in recovery in Australia and the United Kingdom : do stages of recovery differ across national boundaries?

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    The evidence is now clear that more than one half of those who have a lifetime addiction to alcohol or drugs will eventually achieve stable recovery. As documented in the Life in Recovery surveys and elsewhere, recovery often brings about positive changes across a diverse range of life domains. Although this suggests that there are some universal experiences of recovery, there has been a lack of comparative recovery research examining the variations in recovery experiences across different settings and cultures. Using a combined data set of the United Kingdom and Australian Life in Recovery surveys and the three-stage model of recovery, the authors compare life achievements at each stage across the two settings. There are differences in patterns of recovery, with elevated levels of ongoing mental health problems in Australia, and significant involvement with the criminal justice system in the United Kingdom, suggesting a contextual and structural role in understanding recovery pathways. The implications for policy and practice are reviewed around structural barriers and the role of social justice in advancing recovery models and pathways

    Layout of Graphs with Bounded Tree-Width

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    A \emph{queue layout} of a graph consists of a total order of the vertices, and a partition of the edges into \emph{queues}, such that no two edges in the same queue are nested. The minimum number of queues in a queue layout of a graph is its \emph{queue-number}. A \emph{three-dimensional (straight-line grid) drawing} of a graph represents the vertices by points in Z3\mathbb{Z}^3 and the edges by non-crossing line-segments. This paper contributes three main results: (1) It is proved that the minimum volume of a certain type of three-dimensional drawing of a graph GG is closely related to the queue-number of GG. In particular, if GG is an nn-vertex member of a proper minor-closed family of graphs (such as a planar graph), then GG has a O(1)×O(1)×O(n)O(1)\times O(1)\times O(n) drawing if and only if GG has O(1) queue-number. (2) It is proved that queue-number is bounded by tree-width, thus resolving an open problem due to Ganley and Heath (2001), and disproving a conjecture of Pemmaraju (1992). This result provides renewed hope for the positive resolution of a number of open problems in the theory of queue layouts. (3) It is proved that graphs of bounded tree-width have three-dimensional drawings with O(n) volume. This is the most general family of graphs known to admit three-dimensional drawings with O(n) volume. The proofs depend upon our results regarding \emph{track layouts} and \emph{tree-partitions} of graphs, which may be of independent interest.Comment: This is a revised version of a journal paper submitted in October 2002. This paper incorporates the following conference papers: (1) Dujmovic', Morin & Wood. Path-width and three-dimensional straight-line grid drawings of graphs (GD'02), LNCS 2528:42-53, Springer, 2002. (2) Wood. Queue layouts, tree-width, and three-dimensional graph drawing (FSTTCS'02), LNCS 2556:348--359, Springer, 2002. (3) Dujmovic' & Wood. Tree-partitions of kk-trees with applications in graph layout (WG '03), LNCS 2880:205-217, 200

    The Asthma-COPD Overlap Syndrome: A Common Clinical Problem in the Elderly

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    Many patients with breathlessness and chronic obstructive lung disease are diagnosed with either asthma, COPD, or—frequently—mixed disease. More commonly, patients with uncharacterized breathlessness are treated with therapies that target asthma and COPD rather than one of these diseases. This common practice represents the difficulty in distinguishing these disorders clinically, particularly in patients with a history that does not easily differentiate asthma from COPD. A common clinical scenario is an older former smoker with partially reversible or fixed airflow obstruction and evidence of atopy, demonstrating “overlap” features of asthma and COPD. We stress that asthma-COPD overlap syndrome becomes more prevalent with advancing age as patients respond less favorably to guideline-recommended drug therapy. We review the similarities and differences in clinical characteristics between these disorders, and their physiologic and inflammatory profiles within the context of the aging patient. We underscore the difficulties in differentiating asthma from COPD in current or former smokers, share our institutional experience with overlap syndrome, and highlight the need for new research to better characterize and investigate this important clinical phenotype

    Statistics in the Jury Box: How Jurors Respond to Mitochondrial DNA Match Probabilities

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    This article describes parts of an unusually realistic experiment on the comprehension of expert testimony on mitochondrial DNA (mtDNA) sequencing in a criminal trial for robbery. Specifically, we examine how jurors who responded to summonses for jury duty evaluated portions of videotaped testimony involving probabilities and statistics. Although some jurors showed susceptibility to classic fallacies in interpreting conditional probabilities, the jurors as a whole were not overwhelmed by a 99.98% exclusion probability that the prosecution presented. Cognitive errors favoring the defense were more prevalent than ones favoring the prosecution. These findings lend scant support to the legal argument that mtDNA evidence (with modest exclusion probabilities) should be excluded because jurors are prone to overvalue such evidence. The article also introduces a new method for inferring the perceived probability of guilt that satisfies the burden of persuasion for most jurors

    Testing Jury Reforms

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    DNA evidence has become a key law enforcement tool and is increasingly presented in criminal trials in Delaware and elsewhere. The integrity of the criminal trial process turns upon the jury\u27s ability to understand DNA evidence and to evaluate properly the testimony of experts. How well do they do? Can we assist them in the process
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