In this paper, we combine the time-varying financial network model and FARM-selection approach to analyze the tail risk contagion between international financial market during the COVID-19 epidemic. ...Since the tail risk acts as a global transmission channel, we use the sample of 19 international financial markets to explore the contagion of tail risk during the epidemic. We find that the COVID-19 epidemic increases the number of contagion channels in the international financial system. The clustering level of the financial system has a significant growth during the COVID-19 pandemic, and the number of risk drivers is also larger than risk takers. The key financial market of each international financial network is related to the epidemic country. We also consider the tail risk contagion in local financial markets and find that the COVID-19 pandemic has an important influence on the tail risk contagions in local network systems
•Introducing Factor-Adjusted Regularized Model (FARM) selection method into the research on tail risk.•Combines FARM-selection and the rolling-window financial network model to study the tail risk contagion between international markets.•Analyzes the tail risk contagion from the aspects of clustering level, risk drivers and takers.•Provides some implications of the impact of the COVID-19 epidemic.
Effectively forecasting the stock mid-price movements based on Limit Order Book (LOB) data is crucial for issuing the right trade instructions in an automated trading market. The LOB data contains ...much valuable information which reflects the microstructure of the stock market and investor trading behavior. However, there are bear several challenges when utilize LOB to built forecasting model, such as dealing with very large amounts of data with high-dimensional, high-frequency, and underlying nonlinear dependencies relationship. In this paper, we propose a novel deep learning architecture tailored to meet the needs of high-frequency mid-price movements forecasting using complex LOB. Specifically, we introduce dual-stage temporal attention mechanism to repeatedly highlight the most valuable time-dimension information. In the first stage, we adaptively assign the temporal attention weights for input data to emphasize the degree of importance of different moments. In the second stage, we adaptively assign the temporal attention weights for hidden states across all time steps to emphasize the degree of importance of different states. Moreover, the architecture utilizes stacked GRU network to enhance the ability of representation learning. Extensive experiments on two datasets demonstrate the validity and superiority of the proposed architecture. Furthermore, by feature importance analysis we find that the time-sensitive feature set is more important than other feature sets, where the derivation of price and volume is the most important feature in all features. The results provide evidence for further understanding the influence factors of the stock market and give a reference for processing financial time series data with high-frequency characteristics.
•In-situ observation of evapotranspiration (ET) in a data scarce region.•ET from semi-arid alpine steppe was mainly controlled by precipitation.•Different drivers for evapotranspiration for different ...seasons.•ET and precipitation are nearly balanced in the closed basin of central TP.
Characterizing the water and energy flux in the alpine steppe ecosystem in Tibetan Plateau (TP) is of particular importance for elucidating hydrological cycle mechanisms in high altitude areas. In the present study, two years of actual evapotranspiration (ET) values from a semi-arid alpine steppe region (4947m above sea level) and their environmental and biophysical controls were investigated using the energy balance Bowen ratio energy balance (BREB) method. Seasonally, ET was much lower in frozen soil period and transition period mainly because of low soil water availability. However, ample soil water supplied by rainfall during the rainy period substantially increased ET. The available energy played an important role in controlling ET in the rainy period. Also, the leaf-level stomata closure and plant leaf development could impact the ET through changing bulk surface conductance (Gs) in rainy period. Similarly, the land–atmosphere energy exchange was dominated by latent heat flux (λE) in July, but was dominated by sensible heat flux (H) in December and May. Annual ET (plus sublimation) were 362.9mm and 353.4mm in the first and second observation year, respectively, which were close to the annual precipitation. On annual scale, the low Gs (3.30–3.62mms−1), decoupling factor (Ω, 0.25–0.27) and the ratio of ET to equilibrium evapotranspiration (ET/ETeq, 0.34–0.35) corroborated the overall water-limited conditions for the high-altitude alpine steppe. This research provides not only the ground truth data for future hydrological modeling in the data scarce region of TP but also the insights for elucidating how the environmental and biophysical stress factors control the land surface ET in high-altitude region.
Lake water storage change (ΔSw) is an important indicator of the hydrologic cycle and greatly influences lake expansion/shrinkage over the Tibetan Plateau (TP). Accurate estimation of ΔSw will ...contribute to improved understanding of lake variations in the TP. Based on a water balance, this study explored the variations of ΔSw for the Lake Selin Co (the largest closed lake on the TP) during 2003–2012 using the Water and Energy Budget‐based Distributed Hydrological Model (WEB‐DHM) together with two different evapotranspiration (ET) algorithms (the Penman‐Monteith method and a simple sublimation estimation approach for water area in unfrozen and frozen period). The contributions of basin discharge and climate causes to the ΔSw are also quantitatively analyzed. The results showed that WEB‐DHM could well reproduce daily discharge, the spatial pattern, and basin‐averaged values of MODIS land surface temperature (LST) during nighttime and daytime. Compared with the ET reference values estimated from the basin‐wide water balance, our ET estimates showed better performance than three global ET products in reproducing basin‐averaged ET. The modeled ET at point scale matches well with short‐term in situ daily measurements (RMSE = 0.82 mm/d). Lake inflows and precipitation over the water area had stronger relationships with ΔSw in the warm season and monthly scale, whereas evaporation from the water area had remarkable effects on ΔSw in the cold season. The total contribution of the three factors to ΔSw was about 90%, and accounting for 49.5%, 22.1%, and 18.3%, respectively.
Key Points:
Lake water storage changes are quantitatively explored for the largest TP lake
Global products, water balance method, and in situ data are used for evaluation
Lake inflow and climate changes drive the variations of lake water storage
It has been reported that increasingly microRNAs are associated with diseases. However, the patterns among the microRNA-disease associations remain largely unclear. In this study, in order to dissect ...the patterns of microRNA-disease associations, we performed a comprehensive analysis to the human microRNA-disease association data, which is manually collected from publications. We built a human microRNA associated disease network. Interestingly, microRNAs tend to show similar or different dysfunctional evidences for the similar or different disease clusters, respectively. A negative correlation between the tissue-specificity of a microRNA and the number of diseases it associated was uncovered. Furthermore, we observed an association between microRNA conservation and disease. Finally, we uncovered that microRNAs associated with the same disease tend to emerge as predefined microRNA groups. These findings can not only provide help in understanding the associations between microRNAs and human diseases but also suggest a new way to identify novel disease-associated microRNAs.
The complementary relationship (CR) of evapotranspiration allows the estimation of the actual evapotranspiration rate (ETa) of the land surface using only routine meteorological data, which is of ...great importance in the Tibetan Plateau (TP) due to its sparse observation network. With the highest in situ automatic climate observation system in a typical semiarid alpine steppe region of the TP, the wind function of Penman was replaced by one based on the Monin‐Obukhov Similarity theory for calculating the potential evapotranspiration rate (ETp); the Priestley‐Taylor coefficient, α, was estimated using observations in wet days; and the slope of the saturation vapor pressure curve was evaluated at an estimate of the wet surface temperature, provided the latter was smaller than the actual air temperature. A symmetric CR was obtained between the observed daily actual and potential evapotranspiration. Local calibration of the parameter value (in this order) is key to obtaining a symmetric CR: α, wet environment air temperature (Twea), and wind function. Also, present symmetric CR contradicts previous research that used default parameter values for claiming an asymmetric CR in arid and semiarid regions of the TP. The effectiveness of estimating the daily ETa via symmetric CR was greatly improved when local calibrations were implemented. At the same time, an asymmetric CR was found between the observed daily ETa and pan evaporation rates (Epan), both for D20 aboveground and E601B sunken pans. The daily ETa could also be estimated by coupling the Epan of D20 aboveground and/or E601B sunken pan through CR. The former provided good descriptors for observed ETa, while the latter still tended to overestimate it to some extent.
Key Points:
The complementary relationship (CR) of evapotranspiration exists in alpine steppe
Local calibrations reveal the CR pattern in semiarid region of Tibetan Plateau
CR‐based estimation of actual evapotranspiration from semiarid alpine steppe
Fertigation strategy has been shown to impact nitrogen distribution in drip irrigation, but it remains unclear whether it would impose a comparable effect on phosphorus migration in phosphorus ...fertigation. A two-year field experiment was conducted to evaluate the effects of different phosphorus sources (mono-ammonium phosphate (MAP) and ammonium polyphosphate (APP)) and four fertigation strategies with varying sequences and durations of water irrigation and fertilization in the irrigation cycle (i.e., applying the fertilizer for the full irrigation cycle, 1/4 W-1/2 F-1/4 W (first applying water (W) for one-fourth of the total irrigation time, then applying fertilizer solution (F) for one-half of the total irrigation time, followed by applying water (W) for the remaining irrigation time, 1/2 W-1/2 F, and 1/2 F-1/2 W) on soil nutrient distribution, maize yield, and nutrient use efficiency. The results indicated that advancing the fertilization period within an irrigation cycle favored nitrogen and phosphorus migration, especially in the 10–40 cm soil layer. APP enhanced soil phosphorus mobility and availability compared to MAP under a given fertigation strategy, particularly during the maize filling stage. The combined performance of fertigation strategies and phosphorus sources varied in terms of soil nutrient distribution and nutrient uptake. MAP is more suitable for fertigation strategies with more post-fertilization irrigation water. For simultaneous fertigation with nitrogen and phosphate fertilizers, it is recommended to apply nitrogen and weakly adsorbed phosphate fertilizers during the middle of the irrigation cycle, while strongly adsorbed phosphate fertilizers occur earlier, along with appropriately extending the duration of post-fertilization water application.
Many breast cancer patients suffer from obvious side effects induced by chemotherapy. Formononetin (FM), one kind ingredient of Chinese herbal medicine, has been suggested to inhibit MCF-7 breast ...cancer cells. And recently metformin (MET) has gained more attention as a potential anti-cancer drug. The aim of this study was to investigate the synergistic effects of FM and MET on the proliferation of MCF-7 cells and to clarify the possible molecular mechanism involved. MCF-7 cells were treated with various concentrations of FM (40 and 80 μM) or FM (40 and 80 μM) combined with MET (150 μM) for 48 h. Cell proliferation was tested by an methyl tetrazolium (MTT) (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay. The percentage of apoptotic cells was measured by flow cytometry. The expression level of b-cell lymphoma/leukemia-2 (bcl-2) mRNA was examined by RT-PCR, while the expression levels of phosphorylated extracellular signal-regulated kinases (p-ERK1/2) and bcl-2 protein were detected by Western blotting. Compared with untreated cells, 40 μM and 80 μM FM efficiently inhibited proliferation and increased apoptosis in MCF-7 cells. Additionally, 40 μM and 80 μM FM greatly downregulated bcl-2 mRNA expression when compared with untreated cells. Furthermore, the protein expression of bcl-2 and p-ERK1/2 was significantly reduced by 40 μM and 80 μM FM. The cytotoxic effect of FM was more remarkable when 150 μM MET was added. Taken together, the combinational use of FM and MET enhanced cell growth inhibition, and the induction of apoptosis in MCF-7 cells mediated by the ERK1/2 signaling pathway.
Nonalcoholic fatty liver disease (NAFLD) including nonalcoholic steatohepatitis (NASH) has reached epidemic proportions with no pharmacological therapy approved. Lower circulating glycine is ...consistently reported in patients with NAFLD, but the causes for reduced glycine, its role as a causative factor, and its therapeutic potential remain unclear. We performed transcriptomics in livers from humans and mice with NAFLD and found suppression of glycine biosynthetic genes, primarily alanine-glyoxylate aminotransferase 1 (
). Genetic (
mice) and dietary approaches to limit glycine availability resulted in exacerbated diet-induced hyperlipidemia and steatohepatitis, with suppressed mitochondrial/peroxisomal fatty acid β-oxidation (FAO) and enhanced inflammation as the underlying pathways. We explored glycine-based compounds with dual lipid/glucose-lowering properties as potential therapies for NAFLD and identified a tripeptide (Gly-Gly-L-Leu, DT-109) that improved body composition and lowered circulating glucose, lipids, transaminases, proinflammatory cytokines, and steatohepatitis in mice with established NASH induced by a high-fat, cholesterol, and fructose diet. We applied metagenomics, transcriptomics, and metabolomics to explore the underlying mechanisms. The bacterial genus
sensu stricto was markedly increased in mice with NASH and decreased after DT-109 treatment. DT-109 induced hepatic FAO pathways, lowered lipotoxicity, and stimulated de novo glutathione synthesis. In turn, inflammatory infiltration and hepatic fibrosis were attenuated via suppression of NF-κB target genes and TGFβ/SMAD signaling. Unlike its effects on the gut microbiome, DT-109 stimulated FAO and glutathione synthesis independent of NASH. In conclusion, impaired glycine metabolism may play a causative role in NAFLD. Glycine-based treatment attenuates experimental NAFLD by stimulating hepatic FAO and glutathione synthesis, thus warranting clinical evaluation.
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