142 research outputs found

    "Punch" Dickins and the Origin of Canol's Mackenzie Air Fields

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    Correspondence between the Canadian flyer, C.H. "Punch" Dickins, and government officials in Ottawa during the early summer of 1942 reveals that the United States Army began building an "unauthorized" military air route to Norman Wells ... much earlier than the U.S. War Department's official histories admit, and that, although Canada's Cabinet War Committee professedly knew nothing of it, certain Canadian government personnel were privy to the secret. ..

    Yukon Wildlife: A Social History, by Robert G. McCandless

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    The Canol Project, 1942-45

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    ... Except for the fact that the press dramatized the difficulty in constructing a mountain pipeline, the Canol Project is among the least known episodes of the war years in Canada. Yet Canol's contribution to the advance of oil exploration and development in the Mackenzie Basin is one of the significant events of the time. In August 1940, before the U.S. entered World War II, Prime Minister Mackenzie King and President Franklin D. Roosevelt met in Ogdensburg, New York, to decide upon future defence collaboration. Their agreement was the basis for U.S. military activities in Canada that began as soon as the Japanese attacked Pearl Harbour in December 1941. Meanwhile, President Roosevelt had negotiated a deal to supply the Soviet Union with thousands of fighter planes on a "lend-lease" basis. These aircraft would fly to Siberia by way of Alaska, using an air route through northwestern Canada. As soon as the U.S. declared war, American aircraft converged on the region to transport men and materials to Alaska and to prepare the way for delivering the lend-lease airplanes ...

    A multi-resolution, non-parametric, Bayesian framework for identification of spatially-varying model parameters

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    This paper proposes a hierarchical, multi-resolution framework for the identification of model parameters and their spatially variability from noisy measurements of the response or output. Such parameters are frequently encountered in PDE-based models and correspond to quantities such as density or pressure fields, elasto-plastic moduli and internal variables in solid mechanics, conductivity fields in heat diffusion problems, permeability fields in fluid flow through porous media etc. The proposed model has all the advantages of traditional Bayesian formulations such as the ability to produce measures of confidence for the inferences made and providing not only predictive estimates but also quantitative measures of the predictive uncertainty. In contrast to existing approaches it utilizes a parsimonious, non-parametric formulation that favors sparse representations and whose complexity can be determined from the data. The proposed framework in non-intrusive and makes use of a sequence of forward solvers operating at various resolutions. As a result, inexpensive, coarse solvers are used to identify the most salient features of the unknown field(s) which are subsequently enriched by invoking solvers operating at finer resolutions. This leads to significant computational savings particularly in problems involving computationally demanding forward models but also improvements in accuracy. It is based on a novel, adaptive scheme based on Sequential Monte Carlo sampling which is embarrassingly parallelizable and circumvents issues with slow mixing encountered in Markov Chain Monte Carlo schemes

    Deceleration and trapping of heavy diatomic molecules using a ring-decelerator

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    We present an analysis of the deceleration and trapping of heavy diatomic molecules in low-field seeking states by a moving electric potential. This moving potential is created by a 'ring-decelerator', which consists of a series of ring-shaped electrodes to which oscillating high voltages are applied. Particle trajectory simulations have been used to analyze the deceleration and trapping efficiency for a group of molecules that is of special interest for precision measurements of fundamental discrete symmetries. For the typical case of the SrF molecule in the (N,M) = (2, 0) state, the ring-decelerator is shown to outperform traditional and alternate-gradient Stark decelerators by at least an order of magnitude. If further cooled by a stage of laser cooling, the decelerated molecules allow for a sensitivity gain in a parity violation measurement, compared to a cryogenic molecular beam experiment, of almost two orders of magnitude

    A xenon gas purity monitor for EXO

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    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.Comment: 41 pages, 26 figure

    Twelve-year outcomes of watchful waiting versus surgery of mildly symptomatic or asymptomatic inguinal hernia in men aged 50 years and older:a randomised controlled trial

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    Background: Inguinal hernia belongs to the most common surgical pathology worldwide. Approximately, one third is asymptomatic. The value of watchful waiting (WW) in patients with asymptomatic or mildly symptomatic inguinal hernia has been established in a few randomised controlled trials (RCTs). The aim of this study was to assess long-term outcomes of a RCT comparing WW and elective surgery.Methods: In the original study, men aged ≄50 years with an asymptomatic or mildly symptomatic inguinal hernia were randomly assigned to WW or elective repair. In the present study, the primary outcome was the 12-year crossover rate to surgery, secondary outcomes were time-to-crossover, patient regret, pain, quality of life and incarceration. Dutch Trial Registry: NTR629. Findings: Out of 496 originally analysed patients, 488 (98.4%) were evaluable for chart review (WW: n = 258, surgery: n = 230), and 200 (41.0%) for telephone contact (WW: n = 106, surgery: n = 94) between November 2021 and March 2022 with a median 12 years follow-up (IQR 9–14). After 12 years, the estimated cumulative crossover rate to surgery was 64.2%, which was higher in mildly symptomatic than in asymptomatic patients (71.7% versus 60.4%, HR 1.451, 95% CI: 1.064–1.979). Time-to-crossover was longer in asymptomatic patients (50% after 6.0 years versus 2.0 years, p = 0.019). Patient regret was higher in the WW group (37.7 versus 18.0%, p = 0.002), as well as pain/discomfort (p = 0.031). Quality of life did not differ (p = 0.737). In the WW group, incarceration occurred in 10/255 patients (3.9%). Interpretation: During 12-year follow-up, most WW patients crossed over to surgery, significantly earlier with mildly symptomatic hernia. Considering the relatively low incarceration rate, WW might still be an option in asymptomatic patients with a clear preference and being well-informed about pros and cons.</p

    Twelve-year outcomes of watchful waiting versus surgery of mildly symptomatic or asymptomatic inguinal hernia in men aged 50 years and older:a randomised controlled trial

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    Background: Inguinal hernia belongs to the most common surgical pathology worldwide. Approximately, one third is asymptomatic. The value of watchful waiting (WW) in patients with asymptomatic or mildly symptomatic inguinal hernia has been established in a few randomised controlled trials (RCTs). The aim of this study was to assess long-term outcomes of a RCT comparing WW and elective surgery. Methods: In the original study, men aged ≄50 years with an asymptomatic or mildly symptomatic inguinal hernia were randomly assigned to WW or elective repair. In the present study, the primary outcome was the 12-year crossover rate to surgery, secondary outcomes were time-to-crossover, patient regret, pain, quality of life and incarceration. Dutch Trial Registry: NTR629. Findings: Out of 496 originally analysed patients, 488 (98.4%) were evaluable for chart review (WW: n = 258, surgery: n = 230), and 200 (41.0%) for telephone contact (WW: n = 106, surgery: n = 94) between November 2021 and March 2022 with a median 12 years follow-up (IQR 9–14). After 12 years, the estimated cumulative crossover rate to surgery was 64.2%, which was higher in mildly symptomatic than in asymptomatic patients (71.7% versus 60.4%, HR 1.451, 95% CI: 1.064–1.979). Time-to-crossover was longer in asymptomatic patients (50% after 6.0 years versus 2.0 years, p = 0.019). Patient regret was higher in the WW group (37.7 versus 18.0%, p = 0.002), as well as pain/discomfort (p = 0.031). Quality of life did not differ (p = 0.737). In the WW group, incarceration occurred in 10/255 patients (3.9%). Interpretation: During 12-year follow-up, most WW patients crossed over to surgery, significantly earlier with mildly symptomatic hernia. Considering the relatively low incarceration rate, WW might still be an option in asymptomatic patients with a clear preference and being well-informed about pros and cons. Funding: The initial trial was funded by the Netherlands Organisation for Health Research and Development (ZonMW). This long-term study did not receive funding.</p

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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