657 research outputs found

    Real-time motion analytics during brain MRI improve data quality and reduce costs

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    Head motion systematically distorts clinical and research MRI data. Motion artifacts have biased findings from many structural and functional brain MRI studies. An effective way to remove motion artifacts is to exclude MRI data frames affected by head motion. However, such post-hoc frame censoring can lead to data loss rates of 50% or more in our pediatric patient cohorts. Hence, many scanner operators collect additional 'buffer data', an expensive practice that, by itself, does not guarantee sufficient high-quality MRI data for a given participant. Therefore, we developed an easy-to-setup, easy-to-use Framewise Integrated Real-time MRI Monitoring (FIRMM) software suite that provides scanner operators with head motion analytics in real-time, allowing them to scan each subject until the desired amount of low-movement data has been collected. Our analyses show that using FIRMM to identify the ideal scan time for each person can reduce total brain MRI scan times and associated costs by 50% or more

    Prospective Latin American cohort evaluating outcomes of patients with COVID-19 and abnormal liver tests on admission

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    Introduction & objectives: The independent effect of liver biochemistries as a prognostic factor in patients with COVID-19 has not been completely addressed. We aimed to evaluate the prognostic value of abnormal liver tests on admission of hospitalized patients with COVID-19. Materials & methods: We performed a prospective cohort study including 1611 hospitalized patients with confirmed SARS-CoV-2 infection from April 15, 2020 through July 31, 2020 in 38 different Hospitals from 11 Latin American countries. We registered clinical and laboratory parameters, including liver function tests, on admission and during hospitalization. All patients were followed until discharge or death. We fit multivariable logistic regression models, further post-estimation effect through margins and inverse probability weighting. Results: Overall, 57.8% of the patients were male with a mean age of 52.3 years, 8.5% had chronic liver disease and 3.4% had cirrhosis. Abnormal liver tests on admission were present on 45.2% (CI 42.7–47.7) of the cohort (n = 726). Overall, 15.1% (CI 13.4–16.9) of patients died (n = 244). Patients with abnormal liver tests on admission presented higher mortality 18.7% (CI 15.9–21.7), compared to those with normal liver biochemistries 12.2% (CI 10.1–14.6); P 30. Conclusions: The presence of abnormal liver tests on admission is independently associated with mortality and severe COVID-19 in hospitalized patients with COVID-19 infection and may be used as surrogate marker of inflammation.Fil: Mendizabal, Manuel. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Piñero, Federico. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Ridruejo, Ezequiel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones MĂ©dicas e Investigaciones ClĂ­nicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Anders, Margarita. Hospital Aleman; ArgentinaFil: Silveyra, MarĂ­a Dolores. Sanatorio Anchorena; ArgentinaFil: Torre, Aldo. Centro MĂ©dico ABC; MĂ©xicoFil: Montes, Pedro. Hospital Nacional Daniel A. CarriĂłn; PerĂșFil: UrzĂșa, Alvaro. Hospital ClĂ­nico de la Universidad de Chile; ChileFil: Pages, Josefina. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Toro, Luis G.. Hospitales de San Vicente FundaciĂłn de MedellĂ­n y Rionegro; ColombiaFil: DĂ­az, Javier. Hospital Nacional Edgardo Rebagliati Martins; PerĂșFil: Gonzalez Ballerga, Esteban. Universidad de Buenos Aires. Facultad de Medicina. Hospital de ClĂ­nicas General San MartĂ­n; ArgentinaFil: Miranda Zazueta, Godolfino. Instituto Nacional de Ciencias MĂ©dicas y NutriciĂłn; MĂ©xicoFil: Peralta, Mirta. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: GutiĂ©rrez, Isabel. Centro MĂ©dico ABC; MĂ©xicoFil: Michelato, Douglas. Hospital Especializado en Enfermedades Infecciosas Instituto Couto Maia; BrasilFil: Venturelli, Maria Grazia. Hospital Nacional Guillermo Almenara Irigoyen; PerĂșFil: VarĂłn, Adriana. FundaciĂłn Cardio-Infantil; ColombiaFil: Vera Pozo, Emilia. Hospital Regional Dr. Teodoro Maldonado Carbo; EcuadorFil: Tagle, MartĂ­n. ClĂ­nica Anglo-Americana; PerĂșFil: GarcĂ­a, MatĂ­as. Centro de EducaciĂłn MĂ©dica e Investigaciones ClĂ­nicas "Norberto Quirno"; ArgentinaFil: Tassara, Alfredo. Hospital Aleman; ArgentinaFil: Brutti, Julia. Sanatorio Anchorena; ArgentinaFil: Ruiz GarcĂ­a, Sandro. Hospital de VĂ­ctor Lazarte Echegaray; PerĂșFil: Bustios, Carla. ClĂ­nica Delgado; PerĂșFil: Escajadillo, Nataly. Hospital Nacional Almanzor Aguinaga Asenjo; PerĂșFil: Macias, Yuridia. No especifĂ­ca;Fil: Higuera de la Tijera, FĂĄtima. Hospital General de MĂ©xico “Dr. Eduardo Liceaga"; MĂ©xicoFil: GĂłmez, AndrĂ©s J.. Hospital Universitario FundaciĂłn Santa FĂ© de BogotĂĄ; ColombiaFil: Dominguez, Alejandra. Hospital Padre Hurtado; ChileFil: Castillo Barradas, Mauricio. Hospital de Especialidades del Centro MĂ©dico Nacional La Raza; MĂ©xicoFil: Contreras, Fernando. No especifĂ­ca;Fil: Scarpin, Aldana. Centro de EducaciĂłn MĂ©dica e Investigaciones ClĂ­nicas "Norberto Quirno"; ArgentinaFil: Schinoni, Maria Isabel. Hospital Alianza; BrasilFil: Toledo, Claudio. Universidad Austral de Chile; ChileFil: Girala, Marcos. Universidad Nacional de AsunciĂłn; ParaguayFil: Mainardi, Victoria. Hospital Central De las Fuerzas Armadas; UruguayFil: Sanchez, Abel. Hospital Roosevelt; GuatemalaFil: Bessone, Fernando. Provincia de Santa Fe. Ministerio de Salud y Medio Ambiente - Rosario. Hospital Provincial del Centenario; ArgentinaFil: Rubinstein, Fernando Adrian. Instituto de Efectividad ClĂ­nica y Sanitaria; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Silva, Marcelo Oscar. Universidad Austral. Hospital Universitario Austral; Argentin

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

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    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

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    Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

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    A fiducial cross section for W gamma production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137 fb(-1) of data collected using the CMS detector at the LHC. The W -> e nu and mu nu decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.Peer reviewe

    Performance of the CMS muon trigger system in proton-proton collisions at √s = 13 TeV

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    The muon trigger system of the CMS experiment uses a combination of hardware and software to identify events containing a muon. During Run 2 (covering 2015-2018) the LHC achieved instantaneous luminosities as high as 2 × 10 cm s while delivering proton-proton collisions at √s = 13 TeV. The challenge for the trigger system of the CMS experiment is to reduce the registered event rate from about 40 MHz to about 1 kHz. Significant improvements important for the success of the CMS physics program have been made to the muon trigger system via improved muon reconstruction and identification algorithms since the end of Run 1 and throughout the Run 2 data-taking period. The new algorithms maintain the acceptance of the muon triggers at the same or even lower rate throughout the data-taking period despite the increasing number of additional proton-proton interactions in each LHC bunch crossing. In this paper, the algorithms used in 2015 and 2016 and their improvements throughout 2017 and 2018 are described. Measurements of the CMS muon trigger performance for this data-taking period are presented, including efficiencies, transverse momentum resolution, trigger rates, and the purity of the selected muon sample. This paper focuses on the single- and double-muon triggers with the lowest sustainable transverse momentum thresholds used by CMS. The efficiency is measured in a transverse momentum range from 8 to several hundred GeV

    Search for long-lived particles decaying to jets with displaced vertices in proton-proton collisions at root s=13 Te V

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    A search is presented for long-lived particles produced in pairs in proton-proton collisions at the LHC operating at a center-of-mass energy of 13 TeV. The data were collected with the CMS detector during the period from 2015 through 2018, and correspond to a total integrated luminosity of 140 fb(-1). This search targets pairs of long-lived particles with mean proper decay lengths between 0.1 and 100 mm, each of which decays into at least two quarks that hadronize to jets, resulting in a final state with two displaced vertices. No significant excess of events with two displaced vertices is observed. In the context of R-parity violating supersymmetry models, the pair production of long-lived neutralinos, gluinos, and top squarks is excluded at 95% confidence level for cross sections larger than 0.08 fb, masses between 800 and 3000 GeV, and mean proper decay lengths between 1 and 25 mm.Peer reviewe

    Search for top squark production in fully hadronic final states in proton-proton collisions at root s=13 TeV

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    A search for production of the supersymmetric partners of the top quark, top squarks, is presented. The search is based on proton-proton collision events containing multiple jets, no leptons, and large transverse momentum imbalance. The data were collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 137 fb(-1). The targeted signal production scenarios are direct and gluino-mediated top squark production, including scenarios in which the top squark and neutralino masses are nearly degenerate. The search utilizes novel algorithms based on deep neural networks that identify hadronically decaying top quarks and W bosons, which are expected in many of the targeted signal models. No statistically significant excess of events is observed relative to the expectation from the standard model, and limits on the top squark production cross section are obtained in the context of simplified supersymmetric models for various production and decay modes. Exclusion limits as high as 1310 GeVare established at the 95% confidence level on the mass of the top squark for direct top squark production models, and as high as 2260 GeV on the mass of the gluino for gluino-mediated top squark production models. These results represent a significant improvement over the results of previous searches for supersymmetry by CMS in the same final state.Peer reviewe
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