226 research outputs found

    A Deep Learning Approach to Radar-based QPE

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    In this study, we propose a volume-to-point framework for quantitative precipitation estimation (QPE) based on the Quantitative Precipitation Estimation and Segregation Using Multiple Sensor (QPESUMS) Mosaic Radar data set. With a data volume consisting of the time series of gridded radar reflectivities over the Taiwan area, we used machine learning algorithms to establish a statistical model for QPE in weather stations. The model extracts spatial and temporal features from the input data volume and then associates these features with the location-specific precipitations. In contrast to QPE methods based on the Z-R relation, we leverage the machine learning algorithms to automatically detect the evolution and movement of weather systems and associate these patterns to a location with specific topographic attributes. Specifically, we evaluated this framework with the hourly precipitation data of 45 weather stations in Taipei during 2013-2016. In comparison to the operational QPE scheme used by the Central Weather Bureau, the volume-to-point framework performed comparably well in general cases and excelled in detecting heavy-rainfall events. By using the current results as the reference benchmark, the proposed method can integrate the heterogeneous data sources and potentially improve the forecast in extreme precipitation scenarios.Comment: 22 pages, 11 figures. Published in Earth and Space Scienc

    Integrin-mediated membrane blebbing is dependent on the NHE1 and NCX1 activities.

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    Integrin-mediated signal transduction and membrane blebbing have been well studied to modulate cell adhesion, spreading and migration^1-6^. However, the relationship between membrane blebbing and integrin signaling has not been explored. Here we show that integrin-ligand interaction induces membrane blebbing and membrane permeability change. We found that sodium-proton exchanger 1 (NHE1) and sodium-calcium exchanger 1 (NCX1) are located in the membrane blebbing sites and inhibition of NHE1 disrupts membrane blebbing and decreases membrane permeability change. However, inhibition of NCX1 enhances cell blebbing to cause cell swelling which is correlated with an intracellular sodium accumulation induced by NHE17. These data suggest that sodium influx induced by NHE1 is a driving force for membrane blebbing growth, while sodium efflux induced by NCX1 in a reverse mode causes membrane blebbing retraction. Together, these data reveal a novel function of NHE1 and NCX1 in membrane permeability change and blebbing and provide the link for integrin signaling and membrane blebbing

    The Clinical COPD Questionnaire Correlated with BODE Index-A Cross-Sectional Study

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    The Global initiative for Chronic Obstructive Lung Disease (GOLD) staging has widely used in the stratification of the severity of COPD, while BODE (body mass index, airflow obstruction, dyspnea, and exercise capacity) index was proven superior to FEV1 in predicting mortality, exacerbation and disease severity in patients with COPD. Clinical COPD Questionnaire (CCQ), a questionnaire with ten items categorized into three domains (symptoms, functional state and mental state) was developed to measure health status of COPD patients. However, little is known about the relationship between CCQ score and BODE index. We performed a prospective study with the inclusion of 89 patients who were clinically stable after a 6-week-therapy for COPD symptoms comparing their health status assessed by CCQ, BODE index and GOLD staging. We found that the total CCQ score was correlated with BODE score (P < 0.001) and GOLD staging (P < 0.001); of three CCQ domains, the functional status correlated the most with BODE index (rS = 0.670) and GOLD staging (rS = 0.531), followed by symptoms (rS = 0.482; rS = 0.346, respectively), and mental status (rS = 0.340; rS = 0.236, respectively). Our data suggest that CCQ is a reliable and convenient alternative tool to evaluate the severity of COPD

    Association between plasma levels of hyaluronic acid and functional outcome in acute stroke patients

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    BACKGROUND: Activation of hyaluronic acid (HA) and associated enzyme synthesis has been demonstrated in experimental stroke animal models. Our study aimed to investigate the plasma levels of HA in acute stroke patients and the associations between HA levels and functional outcome. METHODS: This was a multicenter case–control study. Acute stroke patients and age- and sex-matched non-stroke controls were recruited. Plasma levels of HA in acute stroke patients were determined at <48 hours and at 48 to 72 hours after stroke onset by standard ELISA. Favorable functional outcome was defined as modified Rankin scale ≤2 at 3 months after stroke. RESULTS: The study included 206 acute stroke patients, including 43 who had intracerebral hemorrhage and 163 who had ischemic stroke, and 159 controls. The plasma levels of HA in the acute stroke patients were significantly higher than those in the controls (219.7 ± 203.4 ng/ml for <48 hours and 343.1 ± 710.3 ng/ml for 48 to 72 hours versus 170.4 ± 127.9 ng/ml in the controls; both P < 0.05). For intracerebral hemorrhage patients, HA ≤500 ng/ml (<48 hours) was an independent favorable outcome predictor (P = 0.016). For ischemic stroke patients, an inverted U-shaped association between plasma HA (48 to 72 hours) and outcome was noted, indicating that ischemic stroke patients with too high or too low plasma HA levels tended to have an unfavorable outcome. CONCLUSION: HA plasma level was elevated in patients with acute stroke, and can predict 3-month functional outcome, particularly for patients with intracerebral hemorrhage

    Associations between Aerosol Types and Chlorophyll-a Concentration over Coastal Area in East Asia from Satellite Observations

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    This study improved significantly the relationship between aerosol optical depth (AOD) and sea surface chlorophyll-a concentration (Chl-a), after considering the effects of sea surface temperature (SST), ocean surface current (OSC) and type of aerosols. The decadal satellite-retrieved Orbview-2/SeaWiFS Chl-a and Terra/MODIS AOD550nm data (from March 2000 to December 2010) were used to investigate the impact of atmospheric aerosols on the Chl-a concentration in the coastal water around the region of East Asia (equator to 75°N and from 100°E to 180°E). Two sets of sequential areas (A1 to A10 and B1 to B9) were selected for examining and excluding the influence of SST and OSC. After taking the potential location of aerosol deposition from OSC into account, an obvious correlation between AOD550nm and Chl-a concentration was demonstrated around the site of study area A. For aerosol partition, the Normalized Gradient Aerosol Index (NGAI) was applied to MODIS AOD products for aerosol type identification and mixed status determination. The results indicated that the type of mineral dust (DS) significantly increases the Chl-a while the biomass burning (BB) aerosols may restrain the Chl-a. This seems to be a non-impact of anthropogenic pollutant (AP) on Chl-a within the surface layer. The other area, B (B1 to B9), next to the region of area A, also shows similar results with high consistency; thus, the significant impact of DS aerosols on Chl-a production is suggested over the coastal region of East Asia

    Gender Difference in Statin Intervention on Blood Lipid Control among Patients with Coronary Heart Disease

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    SummaryBackgroundThe aim of this study was to clarify the current status in the effective control of dyslipidemia in Taiwanese women and men with coronary heart disease (CHD).Materials and methodsA total 1584 patients with CHD (1188 men, aged 64.8 ± 11.6 years and 396 women, aged 69.0 ± 9.8 years) from 3486 patients who had atherosclerotic vascular disease and complete lipids measured values [total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C)] were used for analysis.ResultsThe waist, height, weight, and creatinine levels were higher in men than in women. The systolic blood pressure, TC, HDL-C, LDL-C, fasting blood glucose, and platelet were lower in men than in women. Men were more likely to achieve the target goal than women in TC < 160 mg/dL, LDL-C < 100 mg/dL, and TG < 150 mg/dL as well as to achieve HDL-C goal.ConclusionA significant gap was found between the guidelines and clinical practice in statin intervention among these CHD patients, particularly for women. The strategy in control of dyslipidemia should consider gender difference

    Quantum metric nonlinear Hall effect in a topological antiferromagnetic heterostructure

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    Quantum geometry - the geometry of electron Bloch wavefunctions - is central to modern condensed matter physics. Due to the quantum nature, quantum geometry has two parts, the real part quantum metric and the imaginary part Berry curvature. The studies of Berry curvature have led to countless breakthroughs, ranging from the quantum Hall effect in 2DEGs to the anomalous Hall effect (AHE) in ferromagnets. However, in contrast to Berry curvature, the quantum metric has rarely been explored. Here, we report a new nonlinear Hall effect induced by quantum metric by interfacing even-layered MnBi2Te4 (a PT-symmetric antiferromagnet (AFM)) with black phosphorus. This novel nonlinear Hall effect switches direction upon reversing the AFM spins and exhibits distinct scaling that suggests a non-dissipative nature. Like the AHE brought Berry curvature under the spotlight, our results open the door to discovering quantum metric responses. Moreover, we demonstrate that the AFM can harvest wireless electromagnetic energy via the new nonlinear Hall effect, therefore enabling intriguing applications that bridges nonlinear electronics with AFM spintronics.Comment: 19 pages, 4 figures and a Supplementary Materials with 66 pages, 4 figures and 3 tables. Originally submitted to Science on Oct. 5, 202
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