1,084 research outputs found

    Thermal scale modeling

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    Complex system study data indicate that factors associated with multilayer insulation pose major problem in scale modeling, that numerical analysis aids correction for known compromises of scaling criteria, and that probable errors in scale modeling experiments fall within range predicted by statistical analysis

    Limitations in thermal similitude Final report

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    Thermal scale modeling limitation

    Electron generation of leptons and hadrons with reciprocal alpha-quantized lifetimes and masses

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    Hadron elementary particle measurements have long revealed an alpha-dependence in the long-lived threshold-state lifetimes, together with an alpha-related mass structure, where alpha ~ 1/137 is the fine structure constant. A detailed lifetime analysis shows that of the 156 particles with well-determined lifetimes, the 120 shortest lifetimes have a continuum of values, but the 36 longer lifetimes occur in alpha-spaced groups which are sorted into s, c, b quark flavors. Guided by these lifetime results, we deduce an alpha-generated set of universal mass quanta, based on the electron ground state, which apply to both leptons and hadrons. A low-mass "threshold-state octet" of particles - muon, proton, tau, pion, eta, eta prime, kaon, phi meson - is reproduced to an average mass accuracy of 0.4%, with no adjustable parameters except a small hadronic binding energy. Without the lepton states, the hadron mass pattern is difficult to ascertain.Comment: 106 pages, 33 figures, invited review articl

    Obstetric and Neonatal Outcomes 1 or More Years After a Diagnosis of Breast Cancer

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    OBJECTIVE:To evaluate obstetric and neonatal outcomes of the first live birth conceived 1 or more years after breast cancer diagnosis.METHODS:We performed a population-based study to compare live births between women with a history of breast cancer (case group) and matched women with no cancer history (control group). Individuals in the case and control groups were identified using linked data from the California Cancer Registry and California Office of Statewide Health Planning and Development data sets. Individuals in the case group were diagnosed with stage I-III breast cancer at age 18-45 years between January 1, 2000, and December 31, 2012, and conceived 12 or more months after breast cancer diagnosis. Individuals in the control group were covariate-matched women without a history of breast cancer who delivered during 2000-2012. The primary outcome was preterm birth at less than 37 weeks of gestation. Secondary outcomes were preterm birth at less than 32 weeks of gestation, small for gestational age (SGA), cesarean delivery, severe maternal morbidity, and neonatal morbidity. Subgroup analyses were used to assess the effect of time from initial treatment to fertilization and receipt of additional adjuvant therapy before pregnancy on outcomes of interest.RESULTS:Of 30,021 women aged 18-45 years diagnosed with stage I-III breast cancer during 2000-2012, 553 met the study inclusion criteria. Those with a history of breast cancer and matched women in the control group had similar odds of preterm birth at less than 37 weeks of gestation (odds ratio [OR], 1.29; 95% CI 0.95-1.74), preterm birth at less than 32 weeks of gestation (OR 0.77; 95% CI 0.34-1.79), delivering an SGA neonate (less than the 5th percentile: OR 0.60; 95% CI 0.35-1.03; less than the 10th percentile: OR 0.94; 95% CI 0.68-1.30), and experiencing severe maternal morbidity (OR 1.61; 95% CI 0.74-3.50). Patients with a history of breast cancer had higher odds of undergoing cesarean delivery (OR 1.25; 95% CI 1.03-1.53); however, their offspring did not have increased odds of neonatal morbidity compared with women in the control group (OR 1.15; 95% CI 0.81-1.62).CONCLUSION:Breast cancer 1 or more years before fertilization was not strongly associated with obstetric and neonatal complications

    El Uso de Las Letras como Fuente de Errores de Estudiantes Universitarios en la Resolución de Tareas Algebraicas

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    La presente investigación es un estudio realizado con 194 estudiantes del Centro Universitario de la Costa Sur, en Autlán, México, cuyo objetivo es analizar los errores más comunes que los alumnos de primer semestre presentan en las producciones, al operar con los distintos significados que pueden tener las letras en álgebra y con base a esos resultados, establecer su ubicación dentro de alguna de las cuatro categorías de entendimiento en el uso y significado de las letras en álgebra que propone Küchemann (1980). Los resultados muestran que más de la mitad de los estudiantes de este nivel educativo no manifiestan dificultades al evaluar las letras, manejarlas como objetos o considerar su presencia, sin embargo, sí revelan deficiencias en el discernimiento para comprender el uso y significado de las letras como incógnitas de valor especifico, números generalizados y como variables

    Measurement of hadronic event shapes in high-p T multijet final states at √s = 13 TeV with the ATLAS detector

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    A measurement of event-shape variables in proton-proton collisions at large momentum transfer is presented using data collected at s = 13 TeV with the ATLAS detector at the Large Hadron Collider. Six event-shape variables calculated using hadronic jets are studied in inclusive multijet events using data corresponding to an integrated luminosity of 139 fb−1. Measurements are performed in bins of jet multiplicity and in different ranges of the scalar sum of the transverse momenta of the two leading jets, reaching scales beyond 2 TeV. These measurements are compared with predictions from Monte Carlo event generators containing leading-order or next-to-leading order matrix elements matched to parton showers simulated to leading-logarithm accuracy. At low jet multiplicities, shape discrepancies between the measurements and the Monte Carlo predictions are observed. At high jet multiplicities, the shapes are better described but discrepancies in the normalisation are observed. [Figure not available: see fulltext.

    The ATLAS fast tracKer system

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    The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η-ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation. © The ATLAS collaboratio

    A search for the dimuon decay of the Standard Model Higgs boson with the ATLAS detector

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    A search for the dimuon decay of the Standard Model (SM) Higgs boson is performed using data corresponding to an integrated luminosity of 139 fb(-1) collected with the ATLAS detector in Run 2 pp collisions at root s = 13 TeV at the Large Hadron Collider. The observed (expected) significance over the background-only hypothesis for a Higgs boson with a mass of 125.09 GeV is 2.0 sigma (1.7 sigma). The observed upper limit on the cross section times branching ratio for pp -> H -> mu mu is 2.2 times the SM prediction at 95% confidence level, while the expected limit on a H -> mu mu signal assuming the absence (presence) of a SM signal is 1.1(2.0). The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the SM, is mu = 1.2 +/- 0.6. (C) 2020 The Author(s). Published by Elsevier B.V

    A search for an unexpected asymmetry in the production of e+μ− and e−μ+ pairs in proton-proton collisions recorded by the ATLAS detector at root s = 13 TeV

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    This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e(+)mu(-) and e(-)mu(+) pairs to constrain physics processes beyond the Standard Model. It uses 139 fb(-1) of proton-proton collision data recorded at root s = 13 TeV at the LHC. Targeting sources of new physics which prefer final states containing e(+)mu(-) and e(-)mu(+), the search contains two broad signal regions which are used to provide model-independent constraints on the ratio of cross sections at the 2% level. The search also has two special selections targeting supersymmetric models and leptoquark signatures. Observations using one of these selections are able to exclude, at 95% confidence level, singly produced smuons with masses up to 640 GeV in a model in which the only other light sparticle is a neutralino when the R-parity-violating coupling lambda(23)(1)' is close to unity. Observations using the other selection exclude scalar leptoquarks with masses below 1880 GeV when g(1R)(eu) = g(1R)(mu c) = 1, at 95% confidence level. The limit on the coupling reduces to g(1R)(eu) = g(1R)(mu c) = 0.46 for a mass of 1420 GeV
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