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This letter presents a multiscale low-rank decomposition (MSLRD) method to extract multiscale spatial structures from hyperspectral images. The MSLRD assumes that ground objects have divergent characteristics in changing spatial scales. It decomposes each band image into a series of block-wise matrices, where these low-rank blocks take detailed spatial structures at multiple scales. It formulates the low-rank matrix decomposition problem into minimizing the ranks of all block matrices and adopts the alternative direction of the multiplier method to optimize it. Experiments on Indian Pines and Pavia University data sets show that the MSLRD can greatly improve the classification performance of regular classification on spectral features (i.e., all bands) and perform better than five state-of-the-art spatial feature extraction methods.

The coronavirus disease 2019 (COVID-19) pandemic is a major threat to global health. Relevant studies have shown that ambient temperature may influence the spread of novel coronavirus. However, the effect of ambient temperature on COVID-19 remains controversial. Human mobility is also closely related to the pandemic of COVID-19, which could be affected by temperature at the same time. The purpose of this study is to explore the underlying mechanism of the association of temperature with COVID-19 transmission rate by linking human mobility. The effective reproductive number, meteorological conditions and human mobility data in 47 countries are collected. Panel data models with fixed effects are used to analyze the association of ambient temperature with COVID-19 transmission rate, and the mediation by human mobility. Our results show that there is a negative relationship between temperature and COVID-19 transmission rate. We also observe that temperature is positively associated with human mobility and human mobility is positively related to COVID-19 transmission rate. Thus, the suppression effect (also known as the inconsistent mediation effect) of human mobility is confirmed, which remains robust when different lag structures are used. These findings provide evidence that temperature can influence the spread of COVID-19 by affecting human mobility. Therefore, although temperature is negatively related to COVID-19 transmission rate, governments and the public should pay more attention to control measures since people are more likely to go out when temperature rising. Our results could partially explain the reason why COVID-19 is not prevented by warm weather in some countries., Highlights • There is a negative relationship between temperature and COVID-19 transmission rate. • Temperature is positively associated with human mobility. • Human mobility is positively related to COVID-19 transmission rate. • Human mobility has a suppressing effect on the association between temperature and transmission rate.

Two polysaccharides were isolated successfully from Flammulina velutipes and identified as CHFVP-1 (24.44 kDa) and CHFVP-2 (1497 kDa). Based on the results of Fourier transform-infrared spectroscopy (FT-IR), gas chromatography (GC), gas chromatography–mass spectrometry (GC–MS), and nuclear magnetic resonance (NMR) spectroscopy regarding the structure of CHFVP-1 and CHFVP-2, CHFVP-1 was constructed with the backbone of→6)-α-D-Galp-(1→ and the branch of Galp by an →3,6)-α-D-Manp-(1→attached with T-β-D-Glcp or t-α-L-Fucp side chains. Meanwhile, the CHFVP-2 was a glucan with the construction of →6)-β-D-Glcp-(1→ and T-β-D-Glcp. Moreover, the coagulant activity in vitro of CHFVP-1 and CHFVP-2 was evaluated, and the results showed that CHFVP-1 exerts procoagulant activity by shortening the activated partial thromboplastin time (APTT) and thrombin time (TT), while CHFVP-2 did not reveal a definite coagulant activity. The finding would benefit the further application of F. velutipes in the field of medicine.