4,771 research outputs found

    John T. Loughran--An Appreciation: The Man

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    Violence Prevention: Reaching Adolescents with the Message

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    To identify an effective medium for communicating with adolescents in a large-scale, cost-effective violence prevention program. A set of youth violence prevention programs was established at The Stamford Hospital, a level II trauma center. The traveling version of the program was presented to middle school students in four parts: 1) a rap music video created by our violence prevention staff, 2) a facilitated discussion about dealing with anger, 3) a video of a trauma resuscitation in our emergency department, and 4) a commercial video of a teenage boy paralyzed after a gunshot wound. A written questionnaire with a five-point rating scale (1 to 5) was used to survey the audience 1 month after the program. The survey assessed the respondents\u27 recall of each part of the program and the perceptions of the value of each part in identifying the problem of violence and reducing violent behavior. Results: Of 99 respondents, the highest ratings for retention, problem identification, and impact were given to the commercial video (combined average category ranking of 11.394) and the rap music video (11.182). The trauma resuscitation video and the discussion of anger were ranked as being less effective (10.253 and 9.383, respectively). The audience seemed to comprehend the main point of the program and ranked the program, as a whole, higher than any of the parts when measured by success at problem identification and impact. Effective communication with adolescents is possible through many avenues. Children of the video age respond well to visual material. A violence prevention program should incorporate effective multimedia presentations. A variety of methods hi combination proves to be most effective

    Flexible epidemiological model for estimates and short-term projections in generalised HIV/AIDS epidemics

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    International audienceObjective UNAIDS and country analysts use a simple infectious disease model, embedded in the Estimation and Projection Package (EPP), to generate annual updates on the global HIV/AIDS epidemic. Our objective was to develop modifications to the current model that improve fit to recently observed prevalence trends across countries. Methods Our proposed alternative to the current EPP approach simplifies the model structure and explicitly models changes in average infection risk over time, operationalised using penalised B-splines in a Bayesian framework. We also present an alternative approach to initiating the epidemic that improves standardisation and efficiency, and add an informative prior distribution for changes in infection risk beyond the last data point that enhances the plausibility of short-term extrapolations. Results The spline-based model produces better fits than the current model to observed prevalence trends in settings that have recently experienced levelling or rising prevalence following a steep decline, such as Uganda and urban Rwanda. The model also predicts a deceleration of the decline in prevalence for countries with recent experience of steady declines, such as Kenya and Zimbabwe. Estimates and projections from our alternative model are comparable to those from the current model where the latter performs well. Conclusions A more flexible epidemiological model that accommodates changing infection risk over time can provide better estimates and short-term projections of HIV/AIDS incidence, prevalence and mortality than the current EPP model. The alternative model specification can be incorporated easily into existing analytical tools that are used to produce updates on the global HIV/AIDS epidemic

    Accelerating Binary String Comparisons with a Scalable, Streaming-Based System Architecture Based on FPGAs

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    Pilz S, Porrmann F, Kaiser M, Hagemeyer J, Hogan JM, Rückert U. Accelerating Binary String Comparisons with a Scalable, Streaming-Based System Architecture Based on FPGAs. Algorithms. 2020;13(2): 47.This paper is concerned with Field Programmable Gate Arrays (FPGA)-based systems for energy-efficient high-throughput string comparison. Modern applications which involve comparisons across large data sets—such as large sequence sets in molecular biology—are by their nature computationally intensive. In this work, we present a scalable FPGA-based system architecture to accelerate the comparison of binary strings. The current architecture supports arbitrary lengths in the range 16 to 2048-bit, covering a wide range of possible applications. In our example application, we consider DNA sequences embedded in a binary vector space through Locality Sensitive Hashing (LSH) one of several possible encodings that enable us to avoid more costly character-based operations. Here the resulting encoding is a 512-bit binary signature with comparisons based on the Hamming distance. In this approach, most of the load arises from the calculation of the O ( m ∗ n ) Hamming distances between the signatures, where m is the number of queries and n is the number of signatures contained in the database. Signature generation only needs to be performed once, and we do not consider it further, focusing instead on accelerating the signature comparisons. The proposed FPGA-based architecture is optimized for high-throughput using hundreds of computing elements, arranged in a systolic array. These core computing elements can be adapted to support other string comparison algorithms with little effort, while the other infrastructure stays the same. On a Xilinx Virtex UltraScale+ FPGA (XCVU9P-2), a peak throughput of 75.4 billion comparisons per second—of 512-bit signatures—was achieved, using a design with 384 parallel processing elements and a clock frequency of 200 MHz. This makes our FPGA design 86 times faster than a highly optimized CPU implementation. Compared to a GPU design, executed on an NVIDIA GTX1060, it performs nearly five times faster

    Seeking the Ultraviolet Ionizing Background at z~3 with the Keck Telescope

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    We describe the initial results of a deep long-slit emission line search for redshifted (2.7<z<4.1) Lyman-alpha. These observations are used to constrain the fluorescent Ly-alpha emission from the population of clouds whose absorption produces the higher-column-density component of the Ly-alpha forest in quasar spectra. We use the results to set an upper limit on the ultraviolet ionizing background. Our spectroscopic data obtained with the Keck II telescope at lambda/(Delta lambda FWHM)~2000 reveals no candidate Ly-alpha emission over the wavelength range of 4500-6200 Ang along a 3 arcmin slit in a 5400 s integration. Our 3 sigma upper bound on the mean intensity of the ionizing background at the Lyman limit is J(nu 0) < 2E-21 erg/s/cm**2/Hz/sr for 2.7<z<3.1 (where we are most sensitive), assuming Lyman limit systems have typical radii of 70 kpc (q_0=0.5, H_0=50 km/s/Mpc). This constraint is more than an order of magnitude more stringent than any previously published direct limit. However, it is still a factor of three above the ultraviolet background level expected due to the integrated light of known quasars at z~3. This pilot study confirms the conclusion of Gould \& Weinberg (1996) that integrations of several hours on a 10-m class telescope should be capable of measuring J(nu 0) at high redshift.Comment: 22 pages, 2 postscipt figures. Latex requires aaspp4.sty and epsf.sty (included). Accepted for publication in the Astronomical Journal (Nov 1998

    Adoption of Conservation-Tillage Practices in Cotton Production

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    Replaced with revised version of paper 10/23/07.conservation tillage, cotton, genetically modified seed, herbicide-resistant cotton, stacked-gene cotton, simultaneous logit model, single-equation logit model, technology adoption, Crop Production/Industries,

    Chemiluminescence from reactions with bis-cyclometalated iridium complexes in acidic aqueous solution

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    Chemical reactions between certain bis-cyclometalated iridium complexes, cerium(IV) and organic reducing agents in aqueous solution produce an emission of light which in some cases is more intense than that from analogous reactions with conventional ruthenium-based reagents, thus providing a new avenue for chemically-initiated luminescence detection.<br /

    The significance of motivation in student-centred learning : a reflective case study

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    The theoretical underpinnings of student-centred learning suggest motivation to be an integral component. However, lack of clarification of what is involved in motivation in education often results in unchallenged assumptions that fail to recognise that what motivates some students may alienate others. This case study, using socio-cognitive motivational theory to analyse previously collected data, derives three fuzzy propositions which, collectively, suggest that motivation interacts with the whole cycle of episodes in the teachinglearning process. It argues that the development of the higherlevel cognitive competencies that are implied by the term, student-centred learning, must integrate motivational constructs such as goal orientation, volition, interest and attributions into pedagogical practices

    The fate of indeterminate liver lesions: What proportion are precursors of hepatocellular carcinoma?

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    BACKGROUND: The natural history and incidence of hepatocellular carcinoma (HCC) arising from indeterminate liver lesions are not well described. We aimed to define the incidence of HCC in a cohort of patients undergoing surveillance by magnetic resonance imaging (MRI) and estimate any associations with incident HCC. METHODS: We performed a retrospective follow-up study, identifying MRI scans in which indeterminate lesions had been reported between January 2006 and January 2017. Subsequent MRI scan reports were reviewed for incident HCC arising from indeterminate lesions, data were extracted from electronic patient records and survival analysis performed to estimate associations with baseline factors. RESULTS: One hundred and nine patients with indeterminate lesions on MRI were identified. HCC developed in 19 (17%) patients over mean follow up of 4.6 years. Univariate Cox proportional hazards analysis found incident HCC to be significantly associated with baseline low platelet count (hazard ratio (HR) = 7.3 (95% confidence intervals (CI) 2.1-24.9), high serum alpha-fetoprotein level (HR = 2.7 (95% CI 1.0-7.1)) and alcohol consumption above fourteen units weekly (HR = 3.1 (95% CI 1.1-8.7)). Multivariate analysis, however, found that only low platelet count was independently associated with HCC (HR = 5.5 (95% CI 0.6-5.1)). CONCLUSIONS: HCC arises in approximately one fifth of indeterminate liver lesions over 4.6 years and is associated with a low platelet count at the time of first diagnosis of an indeterminate lesion. Incidence of HCC was more common in people with viral hepatitis and in those consuming > 14 units of alcohol per week. Our data may be used to support a strategy of enhanced surveillance in patients with indeterminate lesions

    Tests of the Accelerating Universe with Near-Infrared Observations of a High-Redshift Type Ia Supernova

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    We have measured the rest-frame B,V, and I-band light curves of a high-redshift type Ia supernova (SN Ia), SN 1999Q (z=0.46), using HST and ground-based near-infrared detectors. A goal of this study is the measurement of the color excess, E_{B-I}, which is a sensitive indicator of interstellar or intergalactic dust which could affect recent cosmological measurements from high-redshift SNe Ia. Our observations disfavor a 30% opacity of SN Ia visual light by dust as an alternative to an accelerating Universe. This statement applies to both Galactic-type dust (rejected at the 3.4 sigma confidence level) and greyer dust (grain size > 0.1 microns; rejected at the 2.3 to 2.6 sigma confidence level) as proposed by Aguirre (1999). The rest-frame II-band light cur ve shows the secondary maximum a month after B maximum typical of nearby SNe Ia of normal luminosi ty, providing no indication of evolution as a function of redshift out to z~0.5. A n expanded set of similar observations could improve the constraints on any contribution of extragalactic dust to the dimming of high-redshift SNe Ia.Comment: Accepted to the Astrophysical Journal, 12 pages, 2 figure
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