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Urban floods/inundation disasters are becoming a prominent problem affecting urban public security due to the impact of global climate change and rapid urbanization. Therefore, research on urban flooding via numerical modelling has important practical significance. According to hydrological and hydrodynamic theories and methods, based on the Storm Water Management Model and the self-developed Graphics Processing Unit (GPU) Accelerated Surface Water Flow and Associated Transport (GAST) model, we explore the best coupling mode, and take Xiaozhai block in Xi'an, China, as the research object to study, through the selected mode, the impact of the change of local land use type on surface inundation and pipe network. The results show that the hydrology–hydrodynamic coupling model (G-S) is more realistic, and its simulation results are more in line with the actual urban flood processes. The results are expected to provide help to other experts and scholars in future model coupling research. [ABSTRACT FROM AUTHOR]

Purpose: At present, it has been found that managing patients with a redetected positive RNA test after recovery from foreign-imported coronavirus disease 2019 (COVID-19) cases in China is challenging. The purpose of the current study was to describe the clinical characteristics of these patients. Methods: This retrospective cohort study included 137 COVID-19 patients who were discharged from the Xi'an Public Health Center from 28 July 2020 to 31 December 2021. We compared the clinical characteristics between positive retest patients and non-positive retest patients. Results: 137 COVID-19 patients entered our study, 27 (19.7%) cases of COVID-19 with a redetected positive RNA test by the end of the follow-up period. Fever [(n = 31 (22.6%)], cough [n = 26 (18.9%)] and sore throat [n = 20 (14.5%)] were the most common initial symptoms among the foreign-imported COVID-19 patients, and there were almost no significant differences in initial symptoms between positive retest patients and non-positive retest patients. The positive retest patients had a higher lymphocyte count (p = 0.031) and lymphocyte percentage (p = 0.007) during readmission. There were generally no significant differences in other routine blood test findings, IgG and IgM antibody responses, between positive retest patients and non-positive retest patients, or in positive retest patients over time (before, during, or after positive patient detection). After readmission, positive retest patients displayed fewer symptoms or no obvious disease progression and more sustained remission by CT imaging. Conclusion: Our findings revealed that the clinical characteristics at the time of initial diagnosis were not closely related to redetected positive RNA tests after recovery from foreign-imported COVID-19 cases. Positive retest patients had virtually no symptoms and displayed no obvious disease progression during readmission. These findings provide important information and clinical evidence for the effective management of foreign-imported COVID-19 patients during their convalescent phase. [ABSTRACT FROM AUTHOR]

Background: Effective management of foreign-imported COVID-19 cases is a new and great challenge for China. Our study focused on the foreign-imported COVID-19 cases to provide detailed data for insights into the prevention, early diagnosis, treatment and control of imported COVID-19. Methods: For this observational and retrospective study, we investigated the clinical characteristics of imported COVID-19 cases that were confirmed by real-time RT-PCR in the Xi'an Public Health Center from 29 March 2020 to 31 August 2020. Results: Of the 79 patients with COVID-19, 19 (24.1%) had exposure to confirmed COVID-19 patients, 15 (19.0%) had exposure to suspicious COVID-19 patients, and 45 (56.9%) had an unclear history of exposure to confirmed patients. The mean age of the patients was 38 years, and 70 (88.7%) patients were male. Except for 2 severe cases, the remaining 58 (73.4%) cases displayed mild or moderate symptoms, and 19 (24.2%) infected patients were asymptomatic. Twenty-one (26.6%) patients were not diagnosed until a third or later nucleic acid test. Ten (12.7%) patients had chronic diseases. The most common manifestations of the patients were cough [18 (22.8%) cases], fever [9 (11.4%) cases] and sore throat [9 (11.4%) cases]. Forty-one (51.9%) cases showed abnormal chest CT images, To date, all patients have been discharged, and no patient has died. Conclusion: The imported COVID-19 cases in Xi'an were mainly young and middle-aged adults with mild or moderate symptoms who had a low rate of comorbidity, showed favourable laboratory and chest CT images, and had a better prognosis. Notably, for suspected COVID-19 cases, at least three consecutive nucleic acid tests should be carried out to avoid missed detection of infected patients. Except for severe cases, high-level medical resources are not necessary in most cases. [ABSTRACT FROM AUTHOR]