18 research outputs found

    Uniform Convergence Analysis of the Discontinuous Galerkin Method on Layer-Adapted Meshes for Singularly Perturbed Problem

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    This paper concerns a discontinuous Galerkin (DG) method for a one-dimensional singularly perturbed problem which possesses essential characteristic of second order convection-diffusion problem after some simple transformations. We derive an optimal convergence of the DG method for eight layer-adapted meshes in a general framework. The convergence rate is valid independent of the small parameter. Furthermore, we establish a sharper L2-error estimate if the true solution has a special regular component. Numerical experiments are also given

    A light-weight full-band speech enhancement model

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    Deep neural network based full-band speech enhancement systems face challenges of high demand of computational resources and imbalanced frequency distribution. In this paper, a light-weight full-band model is proposed with two dedicated strategies, i.e., a learnable spectral compression mapping for more effective high-band spectral information compression, and the utilization of the multi-head attention mechanism for more effective modeling of the global spectral pattern. Experiments validate the efficacy of the proposed strategies and show that the proposed model achieves competitive performance with only 0.89M parameters

    Carbamoylphosphinidene:A Phosphorus Analogue of Carbonyl Nitrene

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    Carbonyl nitrenes are versatile intermediates that have been extensively characterized; however, their phosphorus analogues remain largely unknown. Herein, we report the observation of a rare example of carbonyl phosphinidene NH2C(O)P, which was generated through the photolytic (193 nm) dehydrogenation of phosphinecarboxamide (NH2C(O)PH2) in a solid N2-matrix at 12 K. The characterization of NH2C(O)P in the triplet ground state with matrix-isolation IR and ultraviolet–visible (UV–vis) spectroscopy is supported by comprehensive isotope labeling experiments (D and 15N) and quantum chemical calculations. Upon visible-light irradiation at 680 nm, NH2C(O)P inserts into dihydrogen by the reformation of NH2C(O)PH2 with concomitant isomerization to the more stable aminophosphaketene (NH2PCO). Additionally, the photoisomerization of NH2C(O)PH2 to NH2C(OH) = PH along with decomposition by yielding hydrogen-bonded complexes HNCO···PH3 and HPCO···NH3 has been observed in the matrix

    A follow-up study on the recovery and reinfection of Omicron COVID-19 patients in Shanghai, China

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    ABSTRACTLimited follow-up data is available on the recovery of Omicron COVID-19 patients after acute illness. It is also critical to understand persistence of neutralizing antibody (NAb) and of T-cell mediated immunity and the role of hybrid immunity in preventing SARS-CoV-2 reinfection. This prospective cohort study included Omicron COVID-19 individuals from April to June 2022 in Shanghai, China, during a large epidemic caused by the Omicron BA.2 variant. A total of 8945 patients from three medical centres were included in the follow up programme from November 2022 to February 2023. Of 6412 individuals enrolled for the long COVID analysis, 605 (9.4%) individuals experienced at least one sequelae, mainly had fatigue and mental symptoms specific to Omicron BA.2 infection compared with other common respiratory tract infections. During the second-visit, 548 (12.1%) cases of Omicron reinfection were identified. Hybrid immunity with full and booster vaccination had reduced risk of SARS-CoV-2 reinfection by 0.29-fold (95% CI: 0.63–0.81) and 0.23-fold (95% CI: 0.68–0.87), respectively. For 469 participants willing to the hospital during the first visit, those who received full (72 [IQR, 36–156]) or booster (64 [IQR, 28–132]) vaccination had significantly higher neutralizing antibody titers than those with incomplete vaccination (36 [IQR, 16–79]). Moreover, non-reinfection cases had higher neutralizing antibody titers (64 [IQR, 28–152]) compared to reinfection cases (32 [IQR, 20–69])

    A follow-up study on the recovery and reinfection of Omicron COVID-19 patients in Shanghai, China

    No full text
    Limited follow-up data is available on the recovery of Omicron COVID-19 patients after acute illness. It is also critical to understand persistence of neutralizing antibody (NAb) and of T-cell mediated immunity and the role of hybrid immunity in preventing SARS-CoV-2 reinfection. This prospective cohort study included Omicron COVID-19 individuals from April to June 2022 in Shanghai, China, during a large epidemic caused by the Omicron BA.2 variant. A total of 8945 patients from three medical centers were included in the follow up program from November, 2022 to February, 2023. Of 6412 individuals enrolled for the long COVID analysis, 605 (9.4%) individuals experienced at least one sequelae, mainly had fatigue and mental symptoms specific to Omicron BA.2 infection compared with other common respiratory tract infections. During the second-visit, 548 (12.1%) cases of Omicron reinfection were identified. Hybrid immunity with full and booster vaccination had reduced risk of SARS-CoV-2 reinfection by 0.29-fold (95% CI: 0.63 - 0.81) and 0.23-fold (95% CI: 0.68 - 0.87), respectively. For 469 participants willing to the hospital during the first visit, those who received full (72 [IQR, 36 - 156]) or booster (64 [IQR, 28 - 132]) vaccination had significantly higher neutralizing antibody titers than those with incomplete vaccination (36 [IQR, 16 - 79]). Moreover, non-reinfection cases had higher neutralizing antibody titers (64 [IQR, 28 - 152]) compared to reinfection cases (32 [IQR, 20 - 69]).</p
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