The Asymmetric Overnight Return Anomaly in the Chinese Stock Market

Traditional asset pricing theory suggests that to compensate for the uncertainty that investors bear, risky assets should generate considerably higher rates of return than the risk-free rate. However, the overnight return anomaly in the Chinese stock market, which refers to the anomaly that overnight return is significantly negative, contradicts the risk–return trade-off. We find that this anomaly is asymmetrical, as the overnight return is significantly negative after a negative daytime return, whereas the anomaly does not occur following a positive daytime return. We explain this anomaly from the perspective of investor attention. We show that the attention of individual investors behaves asymmetrically such that they draw more attention on negative daytime returns, and play an essential role in explaining the overnight return puzzle

The Mechanism of Intragranular Acicular Ferrite Nucleation Induced by Mg-Al-O Inclusions

The features of inclusion and microstructure for carbon structural steel containing Mg-Al-O inclusions were studied through the scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). It can be seen that, in Mg-Al-O inclusions, the elements of Mn, Si, and S coexist, and their central mole ratio of Mg/Al varies in a wide range. This value for most inclusions is larger than 0.5, which suggests the formation of solid solution between MgAl2O4 and MgO. After etching, the typical microstructure of intragranular acicular ferrites is observed, which is due to the nucleation effect induced by Mg-Al-O inclusions. From the SEM-EDS mapping images, it is found that the element of sulfur accumulates on the periphery of nucleation inclusion. Moreover, line EDS analysis hints that Mn-depletion zone (MDZ) exists in steel matrix, which is adjacent to the complex inclusion. Combined with the theoretical analysis, this phenomenon can be explained by the absorption of Mn due to the magnesium vacancy in MgAl2O4, and this MDZ promotes the nucleation of intragranular acicular ferrite. Through statistical analysis of SEM images for microstructure, the probabilistic nature of inducing nucleation effect is revealed. These results may be helpful to clarify the nature of oxide metallurgy

Composition and distribution of diatom assemblages in the surface sediments of the Bering Sea

Diatoms collected from the top 1 cm of the surface sediment layer at seven Bering Sea stations during the Fourth Chinese National Arctic Research Expedition (4th CHINARE-Arctic) in 2010 were studied. In total, 101 taxa belonging to 38 genera were found. The species were divided into four groups: eurythermal species, boreal-temperate species, polar species, and sea-ice species. The diatom assemblages at the stations in the southwestern basin area were primarily composed of boreal-temperate species, such as Neodenticula seminae, Thalassiosira trifulta, Rhizosolenia hebetata f. hiemalis, and Actinocyclus curvatulus. The northeastern shelf stations were dominated by polar species, including Fragilariopsis oceanica, Thalassiosira antarctica spora, Thalassiosira nordenskioeldii, and Thalassiosira hyalina. The overall abundance was highest at the basin stations with 3.7 ×106 cells∙g-1 of wet sediment, whereas the eastern shelf stations had the lowest abundance of 0.7×106 cells∙g-1 of wet sediment (excluding the resting spores of Chaetoceros spp.). The relationship between the distribution of the surface sediment diatom assemblages and the environment is discussed

Automatic quantitative analysis of morphology of apoptotic HL-60 cells

Morphological identification is a widespread procedure to assess the presence of apoptosis by visual inspection of the morphological characteristics or the fluorescence images. The procedure is lengthy and results are observer dependent. A quantitative automatic analysis is objective and would greatly help the routine work. We developed an image processing and segmentation method which combined the Otsu thresholding and morphological operators for apoptosis study. An automatic determination method of apoptotic stages of HL-60 cells with fluorescence images was developed. Comparison was made between normal cells, early apoptotic cells and late apoptotic cells about their geometric parameters which were defined to describe the features of cell morphology. The results demonstrated that the parameters we chose are very representative of the morphological characteristics of apoptotic cells. Significant differences exist between the cells in different stages, and automatic quantification of the differences can be achieved

Clinical characteristics of respiratory tract infection caused by Klebsiella pneumoniae in immunocompromised patients: a retrospective cohort study

PurposeWith advancements in medical technology and the growth of an aging society, the number of immunocompromised patients has increased progressively. Klebsiella pneumoniae (K. pneumoniae) is one of the most common opportunistic pathogens, causing a severe disease burden. We aimed to further clarify the differences in respiratory tract K. pneumoniae infections between immunocompromised and immunocompetent populations.MethodsWe retrospectively compared cases of respiratory tract K. pneumoniae infection in immunocompromised and immunocompetent patients admitted to Ruijin Hospital in Shanghai between January 2019 and August 2020 to clarify the differences between the two groups.ResultsWe enrolled 400 immunocompromised patients and 386 immunocompetent patients. Compared to the immunocompetent group, immunocompromised patients were more likely to develop bacteremia and shock and to require mechanical ventilation support during hospitalization. Immunocompromised patients also had a greater probability of polymicrobial infection and a higher rate of antibacterial resistance to carbapenem, which resulted in a higher intensive care unit admission rate, 30-day case fatality rate (CFR), and 6-month CFR. Multivariate analysis indicated that immunocompromised patients with respiratory diseases (odds ratio [OR], 2.189; 95% confidence interval [CI], 1.103-4.344; P = 0.025) and cardiovascular diseases (OR, 2.008; 95% CI, 1.055-3.822; P = 0.034), using mechanical ventilation (OR, 3.982; 95% CI, 2.053-7.722; P = 0.000), or infected with multidrug-resistant K. pneumoniae (OR, 3.870; 95%, 1.577-9.498; P = 0.003) were more likely to have a higher 30-day CFR.ConclusionThe disease burden of K. pneumoniae infection in immunocompromised patients is high. Immunocompromised patients who presented with respiratory diseases and cardiovascular diseases, used mechanical ventilation, or were infected with multidrug-resistant K. pneumoniae experienced a higher 30-day mortality rate

Optimal Operation Strategy for Multi-Energy Microgrid Participating in Auxiliary Service

Since multi-energy microgrid (MEMG) can coordinate various resources to operate as a virtual power plant (VPP), it is an important way to maintain the stable and economic operation of the power systems and decrease the impact of intermittence of distributed energy resources (DERs). However, the potential of MEMG as a VPP has not been thoroughly explored since auxiliary service (AS) market is not fully open for MEMG at present. The relevant challenges include balancing conflict of interests among multiple energy entities, motivating users to adjust flexible loads, integrating multiple flexible resources in energy supply/demand sides and formulating specific policies, etc. To handle these tasks, an optimal operation strategy for MEMG participating in AS is proposed by considering Stackelberg game theory and integrated demand response (IDR). The feasibility of the proposed strategy is validated by a practical MEMG in Hunan, China. The results show that the economic benefits of energy entities are effectively raised and the peak-shaving AS is realized while user satisfaction is also maintained. This work would give reference to the constructor of future AS market to formulate polices about the operation modes and pricing schemes of MEMG