Research on Risk Measurement in Financial Market Based on GARCH-VaR and FHS——An Example of Chinese Bond Market

Accurately measuring the risk of bond market is very important for improving the risk management level of bond market and maintaining the stability of the financial system. Taking ChinaBond New Composite Wealth (gross) Index as the research object, this paper selects the closing price from January 1, 2002 to March 30, 2018, establishes the GARCH, EGARCH and GJR-GARCH model based on normal distribution and t distribution, and finds out the volatility aggregation and the leverage effect of the bond market. Then, this paper use two methods  to measure the risk of the bond market: first, we estimate the value at risk (VaR) of the bond market by the parameter method, using conditional variance estimated by the GARCH models, and we carry out backtesting analysis and the Kupiec failure rate test on measurement accuracy of VaR. The results show that t distribution hypothesis and elimination of autocorrelation of the yield rate can improve the accuracy and robustness of the estimation of the VaR; second, we simulate the future revenue path of the bond market and compare it with the actual loss, using Filtered Historical Simulation (FHS) based on Bootstrap method. The results show that the bond market has leverage effect. The maximum possible loss under extreme conditions can be far greater than the maximum possible revenue. But the estimated VaR under 95% confidence level can predict future risks very well. Finally, according to the conclusion, this paper puts forward some suggestions for regulators and investors from the perspective of risk management

Effects of oligosaccharides on particle structure, pasting and thermal properties of wheat starch granules under different freezing temperatures

peer-reviewedThe effects of fructooligosaccharides (FOS), galactooligosaccharides (GOS), and xylooligosaccharides (XOS) on gelatinization, retrogradation, thermal properties and particle size of wheat starch at different freezing temperatures were studied. The results showed that the wheat starch porosity, particle size, peak viscosity increased with increasing freezing temperature. With the addition of 16% oligosaccharides to starch, the porosity, particle size, crystallinity, initial gelatinization temperature, peak value, breakdown and retrogradation viscosity of the starch granules significantly decreased in the order of XOS > GOS > FOS. However, the pasting temperature of the granules increased. The addition of oligosaccharides (especially XOS, which has the most significant effect in inhibiting starch retrogradation) can inhibit the formation of starch crystal structures to a certain extent, reduce the damage from ice crystals to starch granules and delay starch retrogradation. Therefore, functional oligosaccharides can be used as a potentially effective additive to increase freezing stability in frozen starch-based foods

Nearly a decade-long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan, China).

Uncovering which environmental factors govern community diversity patterns and how ecological processes drive community turnover are key questions related to understand the community assembly. However, the ecological mechanisms regulating long-term variations of bacterioplankton communities in lake ecosystems remain poorly understood. Here we present nearly a decade-long study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing with MiSeq platform. We found strong repeatable seasonal diversity patterns in terms of both common (detected in more than 50% samples) and dominant (relative abundance >1%) bacterial taxa turnover. Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is a key environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern of bacterioplankton communities across the main lake areas within season was overwhelmed by their temporal variabilities. Phylogenetic analysis further indicated that 75%-82% of community turnover was governed by homogeneous selection due to consistent environmental conditions within seasons, suggesting that the microbial communities in Lake Donghu are mainly controlled by niche-based processes. Therefore, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout different lake areas

Phenolic acid-induced phase separation and translation inhibition mediate plant interspecific competition

Phenolic acids (PAs) secreted by donor plants suppress the growth of their susceptible plant neighbours. However, how structurally diverse ensembles of PAs are perceived by plants to mediate interspecific competition remains a mystery. Here we show that a plant stress granule (SG) marker, RNA-BINDING PROTEIN 47B (RBP47B), is a sensor of PAs in Arabidopsis. PAs, including salicylic acid, 4-hydroxybenzoic acid, protocatechuic acid and so on, directly bind RBP47B, promote its phase separation and trigger SG formation accompanied by global translation inhibition. Salicylic acid-induced global translation inhibition depends on RBP47 family members. RBP47s regulate the proteome rather than the absolute quantity of SG. The rbp47 quadruple mutant shows a reduced sensitivity to the inhibitory effect of the PA mixture as well as to that of PA-rich rice when tested in a co-culturing ecosystem. In this Article, we identified the long sought-after PA sensor as RBP47B and illustrated that PA-induced SG-mediated translational inhibition was one of the PA perception mechanisms.This work was supported by funds from the National Natural Science Foundation of China (31970641); the State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Center for Life Sciences; the USDA National Institute of Food and Agriculture, Hatch project 3808 to W.W.; the National Natural Science Foundation of China (31970283); Beijing Nova Program of Science and Technology (Z191100001119027); Capital Normal University and State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, to M.Z.; the European Commission Marie Curie-IEF reSGulating-702473 to E.G.B.; Natural Science Foundation of Fujian Province (2020J01546) to J.L.; Knut and Alice Wallenberg Foundation and Swedish Research Council VR to P.V.B.; International Postdoctoral Exchange Fellowship Program and Postdoctoral Fellowship of Center for Life Sciences, and National Natural Science Foundation of China (3220050423) to Z.X.; and the Postdoctoral Fellowship of Center for Life Sciences to S.Z., Y.L. and C.C.Peer reviewe

The Current Status of Breastfeeding Knowledge and Its Influencing Factors in Nursing Undergraduates: A Cross-Sectional Study in China

The aim of this study was to explore the breastfeeding knowledge of nursing undergraduates and the influencing factors. Human milk (HM) is one of the most effective nutritional supplies to improve early development and physical health, but the current status of breastfeeding in China is still not optimal. The breastfeeding knowledge of perinatal women influences their feeding beliefs and behavior. Nursing undergraduates, as core professionals who will care for perinatal women and provide feeding guidance in the future, can significantly affect feeding behavior of mothers and their babies, so their knowledge of breastfeeding may have a potential impact on breastfeeding in China. However, studies on breastfeeding knowledge among nursing undergraduates in China are limited. A convenience sampling method was conducted in four medical universities in China, and eligible nursing undergraduates were selected. An online survey was collected from 5 July 2022 to 5 August 2022. Categorical data were reported as number and percentage, while continuous data were reported as mean ± SD. Multivariate linear regression was used to evaluate the association between influencing factors and breastfeeding knowledge. The overall mean score of the 460 returned questionnaires was 43.991 out of 100. The pass rate of the questionnaire was only 23.04%. Nursing undergraduates had a relatively better grasp of the benefits of breastfeeding and related advice (correct rates: 67.83%). Birthplace, only child or not, the course in obstetrics and gynecological nursing, the course in pediatrics nursing, and placements in maternity or neonatology units were relevant factors for breastfeeding knowledge (p < 0.05). Nursing undergraduates showed unsatisfactory breastfeeding knowledge. It is urgent to raise the knowledge level of breastfeeding among nursing undergraduates. Medical colleges should optimally structure a curriculum of breastfeeding knowledge. Furthermore, it is also necessary to improve the public’s understanding of breastfeeding and the whole society’s attention to breastfeeding in China

Preparation and luminescence properties of Tm

Various novel SrBi2Ta2O9:Tm3+ blue-emitting materials were achieved via solid-state synthesis. The structure and phase purity of prepared SrBi2Ta2O9:xTm3+ (x = 0.005-0.30 mol) were examined by X-ray powder diffraction. The surface morphology of SrBi2Ta2O9:0.01Tm3+ were studied by scanning electron microscopy. Photoluminescence properties were systematically explored under the monitoring emission (λem = 468 nm) and excitation (λex = 303 nm) spectra. The optimum mole ratio of as-synthesized phosphors was 0.01 mol. The concentration quenching mechanism in the SrBi2Ta2O9 host was due to electric multipole interaction. Particularly, the chromaticity coordinates (0.1334, 0.0474) of SrBi2Ta2O9:0.01Tm3+ are near to those of the commercial BaMgAl10O17:Eu2+. These results validated the SrBi2Ta2O9:Tm3+ phosphor can be utilized good blue-emitting candidate for W-LEDs

Synthesis, characterization and photoluminescence properties of Tm

A series of Ca2YTaO6: Tm3+ blue-emitting phosphors were firstly prepared by the solid-state method. The phase formations and purity of Ca2YTaO6: xTm3+ (x = 0.3%-5% mol) were verified by X-ray powder diffraction. The morphological characteristics of Ca2YTaO6: 0.005Tm3+ were detected by scanning electron microscopy (SEM). Photoluminescence properties were discussed by emission (λem = 460 nm) and excitation (λex = 359 nm) spectra. The critical doping concentration of the products was 0.005 mol. The proposed concentration quenching mechanism in Ca2YTaO6 materials was the electric multipole interaction. Besides, the color coordinates (0.1408, 0.0891) of Ca2YTaO6: 0.005Tm3+ were located in blue region. The results suggested the Ca2YTaO6: Tm3+ phosphors can be promising blue-emitting components for the WLED applications

Study on Mechanism of MSWI Fly Ash Solidified by Multiple Solid Waste-Based Cementitious Material Using the Rietveld Method

A novel multiple solid waste-based cementitious material (MSWCM) was developed to immobilize municipal solid waste incineration (MSWI) fly ash. The compressive strength of MSWCM with different ratios of MSWI fly ash reached the standard requirements after curing for 28 days. X-ray powder diffraction (XRD) in combination with the Rietveld method was employed to investigate the content and phase transformation of hydration products. The main hydration products of pure MSWCM paste were C-S-H, hydroxyapatite, ettringite and C-A-S-H. With increases in curing time, the content of ettringite and C-A-S-H increased significantly. The main hydration products of MSWCM paste with MSWI fly ash were C-S-H and Friedel’s salt. The contents increased markedly with increased curing time from 21.8% to 28.0% and from 8.53% to 16.7%, respectively. Additionally, a small amount of PbHPO4 (0.51–0.96%) and lead phosphate Pb3(PO4)2 (0.14–0.51%) were detected, indicating that phosphate had an effective curing effect on lead ions. The results showed that most of the hydration reactions had started at the initial stage of curing and reacted quickly to form a large number of hydration products. The quantitative analyses of hydration products provide essential information for understanding the immobilization mechanism of MSWI fly ash in MSWCM paste