2,156 research outputs found

    Analytic solution of nonlinear fractional Burgers-type equation by invariant subspace method

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    In this paper we study the analytic solutions of Burgers-type nonlinear fractional equations by means of the Invariant Subspace Method. We first study a class of nonlinear equations directly related to the time-fractional Burgers equation. Some generalizations linked to the forced time-fractional Burgers equations and variable-coefficient diffusion are also considered. Finally we study a Burgers-type equation involving both space and time-fractional derivatives

    Applied Weaving: Mapping Creativity Into Every Strand of a Curriculum

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    The purpose of this paper is to explore the value of adding creativity skills into curriculum mapping documents at the elementary and middle school level, with the goal of gaining some clarity regarding the intrinsic value and ubiquity of teaching for creativity. The language for the maps was taken from Weaving Creativity Into Every Strand of Your Curriculum (Burnett & Figliotti, 2015). The maps were developed after observations of and meetings with classroom teachers in order to assure their accuracy and authenticity. Because the intended purpose of a curriculum map is to provide a sweeping view of targeted content and skills, the maps are non-specific by their nature. As a result, a major challenge of this project continues to be how to find ways to make these maps meaningful to the greater community, who is largely unaware of the meaning and value of creativity. For the purposes of this project, creativity skills were added to the curriculum maps of grades five through eight at the Elmwood Franklin School in Buffalo, New York

    Nonlinear time-fractional dispersive equations

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    In this paper we study some cases of time-fractional nonlinear dispersive equations (NDEs) involving Caputo derivatives, by means of the invariant subspace method. This method allows to find exact solutions to nonlinear time-fractional partial differential equations by separating variables. We first consider a third order time-fractional NDE that admits a four-dimensional invariant subspace and we find a similarity solution. We also study a fifth order NDE. In this last case we find a solution involving Mittag-Leffler functions. We finally observe that the invariant subspace method permits to find explicit solutions for a wide class of nonlinear dispersive time-fractional equations.Comment: 14 pages; in press in Communications in Applied and Industrial Mathematics (2014

    Aortic Arch Thrombus and Pulmonary Embolism in a COVID-19 Patient

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    © 2020 Elsevier Inc. Background: Coronavirus disease 2019 (COVID-19) is associated with endothelial inflammation and a hypercoagulable state resulting in both venous and arterial thromboembolic complications. We present a case of COVID-19-associated aortic thrombus in an otherwise healthy patient. Case Report: A 53-year-old woman with no past medical history presented with a 10-day history of dyspnea, fever, and cough. Her pulse oximetry on room air was 84%. She tested positive for severe acute respiratory syndrome coronavirus 2 infection, and chest radiography revealed moderate patchy bilateral airspace opacities. Serology markers for cytokine storm were significantly elevated, with a serum D-dimer level of 8180 ng/mL (normal \u3c 230 ng/mL). Computed tomography of the chest with i.v. contrast was positive for bilateral ground-glass opacities, scattered filling defects within the bilateral segmental and subsegmental pulmonary arteries, and a large thrombus was present at the aortic arch. The patient was admitted to the intensive care unit and successfully treated with unfractionated heparin, alteplase 50 mg, and argatroban 2 μg/kg/min. Why Should an Emergency Physician Be Aware of This?: Mural aortic thrombus is a rare but serious cause of distal embolism and is typically discovered during an evaluation of cryptogenic arterial embolization to the viscera or extremities. Patients with suspected hypercoagulable states, such as that encountered with COVID-19, should be screened for thromboembolism, and when identified, aggressively anticoagulated

    Chemotherapy-Response Monitoring of Breast Cancer Patients Using Quantitative Ultrasound-Based Intra-Tumour Heterogeneities

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    © 2017 The Author(s). Anti-cancer therapies including chemotherapy aim to induce tumour cell death. Cell death introduces alterations in cell morphology and tissue micro-structures that cause measurable changes in tissue echogenicity. This study investigated the effectiveness of quantitative ultrasound (QUS) parametric imaging to characterize intra-tumour heterogeneity and monitor the pathological response of breast cancer to chemotherapy in a large cohort of patients (n = 100). Results demonstrated that QUS imaging can non-invasively monitor pathological response and outcome of breast cancer patients to chemotherapy early following treatment initiation. Specifically, QUS biomarkers quantifying spatial heterogeneities in size, concentration and spacing of acoustic scatterers could predict treatment responses of patients with cross-validated accuracies of 82 ± 0.7%, 86 ± 0.7% and 85 ± 0.9% and areas under the receiver operating characteristic (ROC) curve of 0.75 ± 0.1, 0.80 ± 0.1 and 0.89 ± 0.1 at 1, 4 and 8 weeks after the start of treatment, respectively. The patients classified as responders and non-responders using QUS biomarkers demonstrated significantly different survivals, in good agreement with clinical and pathological endpoints. The results form a basis for using early predictive information on survival-linked patient response to facilitate adapting standard anti-cancer treatments on an individual patient basis

    Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons

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    We present improved measurements of CP-violation parameters in the decays B0π+πB^0 \to \pi^+ \pi^-, B0K+πB^0 \to K^+ \pi^-, and B0π0π0B^0 \to \pi^0 \pi^0, and of the branching fractions for B0π0π0B^0 \to \pi^0 \pi^0 and B0K0π0B^0 \to K^0 \pi^0. The results are obtained with the full data set collected at the Υ(4S)\Upsilon(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory, corresponding to 467±5467 \pm 5 million BBˉB\bar B pairs. We find the CP-violation parameter values and branching fractions Sπ+π=0.68±0.10±0.03,Cπ+π=0.25±0.08±0.02,AKπ+=0.107±0.0160.004+0.006,Cπ0π0=0.43±0.26±0.05,Br(B0π0π0)=(1.83±0.21±0.13)×106,Br(B0K0π0)=(10.1±0.6±0.4)×106, S_{\pi^+\pi^-} = -0.68 \pm 0.10 \pm 0.03, C_{\pi^+\pi^-} = -0.25 \pm 0.08 \pm 0.02, A_{K^-\pi^+} = -0.107 \pm 0.016 ^{+0.006}_{-0.004}, C_{\pi^0\pi^0} = -0.43 \pm 0.26 \pm 0.05, Br(B^0 \to \pi^0 \pi^0) = (1.83 \pm 0.21 \pm 0.13) \times 10^{-6}, Br(B^0 \to K^0 \pi^0) = (10.1 \pm 0.6 \pm 0.4) \times 10^{-6}, where in each case, the first uncertainties are statistical and the second are systematic. We observe CP violation with a significance of 6.7 standard deviations for B0π+πB^0 \to\pi^+\pi^- and 6.1 standard deviations for B0K+πB^0 \to K^+ \pi^-, including systematic uncertainties. Constraints on the Unitarity Triangle angle α\alpha are determined from the isospin relations among the BππB \to \pi\pi rates and asymmetries. Considering only the solution preferred by the Standard Model, we find α\alpha to be in the range [71,109][71^\circ,109^\circ] at the 68% confidence level.Comment: 18 pages, 11 postscript figures, submitted to Phys. Rev.
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