ABSTRACT
This paper examines and analyses the volatility of precious metal assets and the portfolios management. The innovative study of precious metal assets and equity portfolios is instructive and forward-looking under the background of global COVID-19. We use GARCH model, Markowitz model, CAPM Model and Fama-French Three-Factor Model to study volatility, asset forecasts, and the relationship between asset prices and markets. The results show that, firstly, precious metals are less volatile than stocks;secondly, precious metals, especially gold, make up a large percentage of rational risk-hedged portfolios;and finally, the stock prices have an almost linear relationship with the market, but precious metal prices do not have a linear relationship with the market. Our conclusion suggests that investors should consider precious metal assets, especially gold, in addition to stocks when considering their portfolios, which helps to hedge investment risk and provides some guidance to the market. © 2022 SPIE.
ABSTRACT
Background: Based on the current prevalence of Coronavirus Disease 2019 (COVID-19), early diagnosis, isolation, and treatment are important methods to prevent and control infectious diseases. The establishment of convenient and efficient immunochromatographic detection techniques is essential for the prevention and control of COVID-19 epidemic. Objective: To establish a method for the detection of SARS-CoV-2 anti-N protein IgG antibody by immun of luorescence chromatography method based on quantum dots labeling technology in August, 2020. In order to determine whether the detected persons had been infected with COVID-19 or been injected with SARS-CoV-2 inactivated vaccine. Methods The prepared rat anti-human secondary antibody and anti-N protein antibody were immobilized on a Nitrocellulose (NC) membrane as detection line (T) and quality control line (C), respectively. Then the SARS-CoV-2 N protein labeled by quantum dots was evenly sprayed on glass fiber, which was assembled, cut and packaged into test strips after drying. The test strips were used to detect the clinical serum of 35 COVID-19 patients and 50 healthy individuals, the results of the initial screening of the ELISA kit were used as a control to calculate the detection specificity and sensitivity of quantum dots fluorescence immunochromatography. The sensitivity of the test strip was detected by using the N protein antibody standard. Results The specificity and sensitivity of the strip were 100.00%, 94.29%, and the susceptibility was 8.53-17.06 ng/ml antibody concentration. Conclusion: The detection of anti-N protein IgG antibody in serum by quantum dots labeling is simple, fast, with strong sensitivity and specificity. Copyright © 2022 by the Chinese General Practice.