568 research outputs found

    Friction factor and heat transfer correlation for irradiated organic coolants

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    "September 1965."Series statement handwritten on cover"MIT-334-23 Chemistry."Also written as an M.S. theses written by the first author and advised by the second author, Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1966Includes bibliographical references (pages 163-165)M.I.T. DSR Project no. 9819Work performed for the Savannah River Operations Office, U.S. Atomic Energy Commission under contract no. AT(38-1)-33

    In-pile loop irradiation studies of organic coolant materials : progress report, October 1, 1963 - December 31, 1964,

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    Statement of responsibility on title page reads: Report prepared by: E. A. Mason, Project Supervisor; Contributors: W.N. Bley, J.C. Kim, T.H. Timmins, J.F. Terrien, A.H. Swan"Issued: February 1, 1965.""AEC Research and Development Report"--Cover"MIT-334-12."Includes bibliographical references (leaves 21-22)Progress report; October 1, 1963 - December 31, 1964M.I.T. Project no. DSR 9819U.S. Atomic Energy Commission, Savannah River Operations Office contract no. AT(38-1)-33

    Feasibility, reliability and validity of a questionnaire on healthcare consumption and productivity loss in patients with a psychiatric disorder (TiC-P)

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    Background: Patient self-report allows collecting comprehensive data for the purpose of performing economic evaluations. The aim of the current study was to assess the feasibility, reliability and a part of the construct validity of a commonly applied questionnaire on healthcare utilization and productivity losses in patients with a psychiatric disorder (TiC-P). Methods. Data were derived alongside two clinical trials performed in the Netherlands in patients with mental health problems. The response rate, average time of filling out the questionnaire and proportions of missing values were used as indicators of feasibility of the questionnaire. Test-retest analyses were performed including Cohen's kappa and intra class correlation coefficients to assess reliability of the data. The construct validity was assessed by comparing patient reported data on contacts with psychotherapists and reported data on long-term absence from work with data derived from registries. Results: The response rate was 72%. The mean time needed for filling out the first TiC-P was 9.4 minutes. The time needed for filling out the questionnaire was 2.3 minutes less for follow up measurements. Proportions of missing values were limited (< 2.4%) except for medication for which in 10% of the cases costs could not be calculated. Cohen's kappa was satisfactory to almost perfect for most items related to healthcare consumption and satisfactory for items on absence from work and presenteeism. Comparable results were shown by the ICCs on variables measuring volumes of medical consumption and productivity losses indicating good reliability of the questionnaire. Absolute agreement between patient-reported data and data derived from medical registrations of the psychotherapists was satisfactory. Accepting a margin o

    The impacts of Information and Communications Technology (ICT) and E-commerce on bilateral trade flows

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    This study examines the impact of Internet and e-commerce adoption on bilateral trade flows using a panel of 21 developing- and least-developed countries and 30 OECD countries. Given the commitment of East African Community (EAC) to become the frontrunner in export-led economy across the African continent, special attention is dedicated to analyse the role of ICT and e-commerce on EAC’s export performance. The empirical results indicate that better access to the modern ICT and adoption of e-commerce applications stimulate bilateral trade flows at various levels. The study notes that the efficient use of ICT equipped with high speed internet and secured servers is a crucial milestone for unlocking the e-trade potentials for developing- and least-developed counties

    Head Mounted Display Interaction Evaluation: Manipulating Virtual Objects in Augmented Reality

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    Augmented Reality (AR) is getting close to real use cases,which is driving the creation of innovative applications and the unprecedented growth of Head-Mounted Display (HMD) devices in consumer availability. However, at present there is a lack of guidelines, common form factors and standard interaction paradigms between devices, which has resulted in each HMD manufacturer creating their own specifications. This paper presents the first experimental evaluation of two AR HMDs evaluating their interaction paradigms, namely we used the HoloLens v1 (metaphoric interaction) and Meta2 (isomorphic interaction). We report on precision, interactivity and usability metrics in an object manipulation task-based user study. 20 participants took part in this study and significant differences were found between interaction paradigms of the devices for move tasks, where the isomorphic mapped interaction outperformed the metaphoric mapped interaction in both time to completion and accuracy, while the contrary was found for the resize task. From an interaction perspective, the isomorphic mapped interaction (using the Meta2) was perceived as more natural and usable with a significantly higher usability score and a significantly lower task-load index. However, when task accuracy and time to completion is key mixed interaction paradigms need to be considered

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    The Morphology of the Asteroidal Dust around White Dwarf Stars: Optical and Near-infrared Pulsations in G29-38

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    More than 36 yr have passed since the discovery of the infrared excess from circumstellar dust orbiting the white dwarf G29-38, which at 17.5 pc it is the nearest and brightest of its class. The precise morphology of the orbiting dust remains only marginally constrained by existing data, subject to model-dependent inferences, and thus fundamental questions of its dynamical origin and evolution persist. This study presents a means to constrain the geometric distribution of the emitting dust using stellar pulsations measured at optical wavelengths as a variable illumination source of the dust, which reradiates primarily in the infrared. By combining optical photometry from the Whole Earth Telescope with 0.7-2.5 μm spectroscopy obtained with SpeX at NASA’s Infrared Telescope Facility, we detect luminosity variations at all observed wavelengths, with variations at most wavelengths corresponding to the behavior of the pulsating stellar photosphere, but toward the longest wavelengths the light curves probe the corresponding time variability of the circumstellar dust. In addition to developing methodology, we find the pulsation amplitudes decrease with increasing wavelength for principal pulsation modes, yet increase beyond ≈2 μm for nonlinear combination frequencies. We interpret these results as combination modes derived from the principal modes of identical ℓ values and discuss the implications for the morphology of the warm dust. We also draw attention to some discrepancies between our findings and theoretical expectations for the results of the nonlinearity imposed by the surface convection zone on mode-mode interactions and on the behavior of the first harmonic of the highest-amplitude pulsation mode

    Low Phytoestrogen Levels in Feed Increase Fetal Serum Estradiol Resulting in the “Fetal Estrogenization Syndrome” and Obesity in CD-1 Mice

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    doi:10.1289/ehp.10448Although estrogenic chemicals can disrupt development of the reproductive system, there is debate about whether phytoestrogens in soy are beneficial, benign, or harmful. We compared reproductive and metabolic characteristics in male and female mice reared and maintained on non-soy low-phytoestrogen feed or soy-based high-phytoestrogen feed. Removing phytoestrogens from mouse feed produces an obese phenotype consistent with metabolic syndrome, and the associated reproductive system abnormalities are consistent with FES due to elevated endogenous fetal estradiol. Laboratory rodents may have become adapted to high-phytoestrogen intake over many generations of being fed soy-based commercial feed; removing all phytoestrogens from feed leads to alterations that could disrupt many types of biomedical research
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