31 research outputs found

    The design and construction of an electronic D-C analog computer

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    To make this project realizable with the funds available and in the time allowed, and to set forth some definite goals, the following objectives were adopted: Design, construct, and place in working order a d-c electronic analog computer capable of solving 4th order linear differential equations with constant coefficients. Include in the design provisions for real time computation, and also fast, repetitive operation. Provide for later expansion of the computer installation. Limit expenditures to $700 --Introduction, page 4

    Study of Gluon versus Quark Fragmentation in ΄→ggÎł\Upsilon\to gg\gamma and e+e−→qqˉγe^{+}e^{-}\to q\bar{q}\gamma Events at \sqrt{s}=10 GeV

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    Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio R(chrg) for the mean charged multiplicity observed in Upsilon(1S)->gggamma events, to the mean charged multiplicity observed in e+e- -> qqbar gamma events. We find R(chrg)=1.04+/-0.02+/-0.05 for jet-jet masses less than 7 GeV.Comment: 15 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    METERON Analog-1: A Touch Remote

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    The METERON project (Multipurpose End-To-End Robotics Operations Network) was implemented by the European Space Agency as an initiative to prepare Europe for future humanrobotic exploration scenarios that in particular, focused on examination of the human-robotic partnership, and how this partnership could be optimized through an evaluation of the tools and methodologies utilized in the experiments in the domains of operations, communications and robotics (specifically with respect to control strategies)

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Evidence for Fluctuating Wind in Shaping an Ancient Martian Dune Field: The Stimson Formation at the Greenheugh Pediment, Gale Crater

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    International audienceTemporal fluctuations of wind strength and direction can influence aeolian bedform morphology and orientation, which can be encoded into the architecture of aeolian deposits. These strata represent a direct record of atmospheric processes and can be used to understand ancient Martian atmospheric processes as well as those on Earth. The strata can: give insight to ancient atmospheric circulation, how the atmosphere evolved in response to global changes in habitability, and how ancient processes differ from modern processes. The Stimson formation at the Greenheugh pediment (Gale crater) records evidence of fluctuating wind across multiple temporal scales. The strata can be subdivided into three intervals-Gleann Beag, Ladder, and Edinburgh intervals. Internally, the intervals record changes of dune morphology and orientation, correlatable to wind fluctuations at multiple temporal scales. The basal Gleann Beag interval comprises compound cross-strata, deposited by oblique compound dunes. These dunes record a bimodal wind regime, resulting in net sediment transport toward the north. The Ladder interval records a reversal of sediment transport to the south, where straight-crested simple-dunes shaped by a seasonally variable winds formed. Finally, the Edinburgh interval records sediment transport to the west, where a unimodal wind formed sinuous-crested simple dunes. These observations demonstrate active and variable atmospheric circulation in Gale crater during the accumulation of the Stimson dune field, at multiple temporal scales from seasonally driven winds to much longer time-frames, during the Hesperian. These observations can be used to further understand ancient atmospheric conditions and processes, at a high temporal resolution on Mars

    POLARBEAR: Ultra-high Energy Physics with Measurements of CMB Polarization

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    International audiencePOLARBEAR is a ground-based experiment to measure polarization anisotropy in the Cosmic Microwave Background. It is designed to have a combination of sensitivity, foreground mitigation, and rejection of systematic errors to search for the B-mode signature of Inflationary gravity waves over much of the parameter range suggested by simple power-law Inflation models. POLARBEAR is designed to detect a gravitational-wave signature with a tensor-to-scalar ratio r as low as 0.025 (95% confidence). POLARBEAR will also measure polarized lensing of the Cosmic Microwave Background which will give valuable information on large-scale structure at z>1 and bound the total mass of the neutrinos. POLARBEAR will have a 3.5 meter primary meter giving it an angular resolution of 3.0' at its main observation frequency band centered at 150 GHz. The 250 mK focal plane design contains 637 dual-polarization pixels (1274 bolometers) that are coupled to the telescope using microlithographed planar antennas. The experiment will be sited in the Atacama Desert in Chile at 5000 meter (16,500 ft) altitude starting in 2009 after a prototype testing stage at Cedar Flats California. The first configuration of the experiment will observe at only one frequency band with the first season at 150 GHz and the second at 220 GHz. The optics will be upgraded to have simultaneous observations in those two bands in the third season of observations. POLARBEAR and QUIET will observe the same sky patches, and together they will have frequency bands at 30, 40, 90, 150, and 220 GHz giving broad coverage of galactic foregrounds and a valuable cross-check by comparison of polarization maps. In POLARBEAR, polarization systematic errors are mitigated by a continuously rotating 50 K half-wave plate and an observation strategy that takes advantage of parallactic angle rotation to rotate the experiment relative to polarization patterns on the sky

    Ultra high energy cosmology with POLARBEAR

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    Observations of the temperature anisotropy of the Cosmic Microwave Background (CMB) lend support to an inflationary origin of the universe, yet no direct evidence verifying inflation exists. Many current experiments are focussing on the CMB's polarization anisotropy, specifically its curl component (called "B-mode" polarization), which remains undetected. The inflationary paradigm predicts the existence of a primordial gravitational wave background that imprints a unique B-mode signature on the CMB's polarization at large angular scales. The CMB B-mode signal also encodes gravitational lensing information at smaller angular scales, bearing the imprint of cosmological large scale structures (LSS) which in turn may elucidate the properties of cosmological neutrinos. The quest for detection of these signals; each of which is orders of magnitude smaller than the CMB temperature anisotropy signal, has motivated the development of background-limited detectors with precise control of systematic effects. The POLARBEAR experiment is designed to perform a deep search for the signature of gravitational waves from inflation and to characterize lensing of the CMB by LSS. POLARBEAR is a 3.5 meter ground-based telescope with 3.8 arcminute angular resolution at 150 GHz. At the heart of the POLARBEAR receiver is an array featuring 1274 antenna-coupled superconducting transition edge sensor (TES) bolometers cooled to 0.25 Kelvin. POLARBEAR is designed to reach a tensor-to-scalar ratio of 0.025 after two years of observation -- more than an order of magnitude improvement over the current best results, which would test physics at energies near the GUT scale. POLARBEAR had an engineering run in the Inyo Mountains of Eastern California in 2010 and will begin observations in the Atacama Desert in Chile in 2011
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