632 research outputs found

    Improved inapproximability factors for some Σ^p₂ minimization problems

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    We give improved inapproximability results for some minimization problems in the second level of the Polynomial-Time Hierarchy. Extending previous work by Umans [Uma99], we show that several variants of DNF minimization are Σ^p₂-hard to approximate to within factors of n^(1/3−ϵ) and ^(n1/2−ϵ) (where the previous results achieved n^(1/4−ϵ)), for arbitrarily small constant ϵ > 0. For one problem shown to be inapproximable to within n^(1/2−ϵ), we give a matching O(n^(1/2))-approximation algorithm, running in randomized polynomial time with access to an NP oracle, which shows that this result is tight assuming the PH doesn't collapse

    SDSU Cow-Calf Teaching and Research Unit

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    The SDSU Cow/Calf Teaching and Research Unit serves as a resource for teaching, research, extension and student organizations. In addition to use in the classroom, cattle are used for the annual SDSU Little International, Block & Bridle activities, field days, and numerous 4-H, FFA, and other educational events. Recent research projects at the Unit include studies on estrus synchronization, winter supplementation, and absorption of colostrum. For teaching purposes, cattle that vary in calving ease, growth rate, mature size, and maternal value are maintained. It is not feasible to maintain all of the breeds that are important in this region. The herd consists of 100 purebred Angus and Simmental x Angus cows and their calves. Tables 1 and 2 show the average expected progeny differences for the current sires, replacement heifers and the 2002 calf cro

    Fault de-interleaving for reliability in high-speed circuits

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    Prevalence of Abnormal Radiological Findings in Health Care Workers with Latent Tuberculosis Infection and Correlations with T Cell Immune Response

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    More than half of all health care workers (HCWs) in high TB-incidence, low and middle income countries are latently infected with tuberculosis (TB). We determined radiological lesions in a cohort of HCWs with latent TB infection (LTBI) in India, and determined their association with demographic, occupational and T-cell immune response variables.We obtained chest radiographs of HCWs who had undergone tuberculin skin test (TST) and QuantiFERON-TB Gold In Tube (QFT), an interferon-gamma release assay, in a previous cross-sectional study, and were diagnosed to have LTBI because they were positive by either TST or QFT, but had no evidence of clinical disease. Two observers independently interpreted these radiographs using a standardized data form and any discordance between them resolved by a third observer. The radiological diagnostic categories (normal, suggestive of inactive TB, and suggestive of active TB) were compared with results of TST, QFT assay, demographic, and occupational covariates.A total of 330 HCWs with positive TST or QFT underwent standard chest radiography. Of these 330, 113 radiographs (34.2%) were finally classified as normal, 206 (62.4%) had lesions suggestive of inactive TB, and 11 (3.4%) had features suggestive of active TB. The mean TST indurations and interferon-gamma levels in the HCWs in these three categories were not significantly different. None of the demographic or occupational covariates was associated with prevalence of inactive TB lesions on chest radiography.In a high TB incidence setting, nearly two-thirds of HCWs with latent TB infection had abnormal radiographic findings, and these findings had no clear correlation with T cell immune responses. Further studies are needed to verify these findings and to identify the causes and prognosis of radiologic abnormalities in health care workers

    Search Engine Optimisation in UK news production

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    This is an Author's Accepted Manuscript of an article published in Journalism Practice, 5(4), 462 - 477, 2011, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/17512786.2010.551020.This paper represents an exploratory study into an emerging culture in UK online newsrooms—the practice of Search Engine Optimisation (SEO), which assesses its impact on news production. Comprising a short-term participant observational case study at a national online news publisher, and a series of semi-structured, in-depth interviews with SEO professionals at three further UK media organisations, the author sets out to establish how SEO is operationalised in the newsroom, and what consequences these practices have for online news production. SEO practice is found to be varied and application is not universal. Not all UK news organisations are making the most of SEO even though some publishers take a highly sophisticated approach. Efforts are constrained by time, resources and management support, as well as off-page technical issues. SEO policy is found, in some cases, to inform editorial policy, but there is resistance to the principal of SEO driving decision-making. Several themes are established which call for further research

    Producción académica y desempeño docente en una universidad privada de la región San Martín – Perú, 2021

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    La presente investigación tuvo como objetivo, Determinar la relación entre producción académica y desempeño docente en la escuela de Derecho de una Universidad privada de la región San Martín – Perú, 2021. El tipo de investigación básica, con diseño no experimental, la población y muestra estuvo conformada 80 docentes; la técnica la encuesta y el instrumento, el cuestionario. Los resultados del nivel de la producción académica fueron medio con un 47,5 %. El nivel de las dimensiones de la producción académica que más destaca fue las publicaciones, con un 60 % en un nivel bajo, El nivel de desempeño docente fue bueno con el 90 %. El nivel de dimensiones del desempeño docente que más resalta fue la del dominio tecnológico, con un 86.25 %también fue bueno. Se concluyó que, no existe relación entre la producción académica y el desempeño docente en la Escuela de Derecho de una universidad privada de la región San Martín – Perú, 2021. Mediante el análisis estadístico del coeficiente de correlación de Rho de Spearman se alcanzó el 0,064 y una significancia bilateral de 0,570 siendo mayor que 0,05; por lo que, se acepta la H0 y rechaza la hipótesis alterna

    Early Contrast Enhancement: a novel Magnetic Resonance Imaging biomarker of pleural malignancy

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    Introduction: Pleural Malignancy (PM) is often occult on subjective radiological assessment. We sought to define a novel, semi-objective Magnetic Resonance Imaging (MRI) biomarker of PM, targeted to increased tumour microvessel density (MVD) and applicable to minimal pleural thickening. Materials and methods: 60 consecutive patients with suspected PM underwent contrast-enhanced 3-T MRI then pleural biopsy. In 58/60, parietal pleura signal intensity (SI) was measured in multiple regions of interest (ROI) at multiple time-points, generating ROI SI/time curves and Mean SI gradient (MSIG: SI increment/time). The diagnostic performance of Early Contrast Enhancement (ECE; which was defined as a SI peak in at least one ROI at or before 4.5 min) was compared with subjective MRI and Computed Tomography (CT) morphology results. MSIG was correlated against tumour MVD (based on Factor VIII immunostain) in 31 patients with Mesothelioma. Results: 71% (41/58) patients had PM. Pleural thickening was <10 mm in 49/58 (84%). ECE sensitivity was 83% (95% CI 61–94%), specificity 83% (95% CI 68–91%), positive predictive value 68% (95% CI 47–84%), negative predictive value 92% (78–97%). ECE performance was similar or superior to subjective CT and MRI. MSIG correlated with MVD (r = 0.4258, p = .02). Discussion: ECE is a semi-objective, perfusion-based biomarker of PM, measurable in minimal pleural thickening. Further studies are warranted
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