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Second-order error analysis of the averaged L1 scheme L1 for time-fractional initial-value and subdiffusion problems

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Science China Mathematics 2024年第7期67卷 1641-1664页

作者： Jinye Shen Fanhai Zeng Martin Stynes School of Mathematics Southwestern University of Finance and EconomicsChengdu611130China School of Mathematics Shandong UniversityJinan250100China Applied and Computational Mathematics Division Beijing Computational Science Research CenterBeijing100193China

Fractional initial-value problems(IVPs) and time-fractional initial-boundary value problems(IBVPs), each with a Caputo temporal derivative of order α ∈(0, 1), are considered. An averaged variant of the well-known L1 scheme is proved to be O(N^(-2)) convergent for IVPs on suitably graded meshes with N points, thereby improving the O(N^(-(2-α))) convergence rate of the standard L1 scheme. The analysis relies on a delicate decomposition of the temporal truncation error that yields a sharp dependence of the order of convergence on the degree of mesh grading used. This averaged L1 scheme can be combined with a finite difference or piecewise linear finite element discretization in space for IBVPs, and under a restriction on the temporal mesh width, one gets again O(N^(-2)) convergence in time, together with O(h^(2)) convergence in space,where h is the spatial mesh width. Numerical experiments support our results.

关键词： time-fractional subdiffusion averaged L1 scheme

Machine learning model based on non-convex penalized huberized-SVM

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Journal of Electronic Science and Technology 2024年第1期22卷 81-94页

作者： Peng Wang Ji Guo Lin-Feng Li School of Finance and economics Xizang Minzu UniversityXianyang712082China Research center for Quality Development of Xizang Special Industries Xianyang712082China School of Computer Science and Technology Xinjiang UniversityUrumqi830017China

The support vector machine(SVM)is a classical machine learning *** the hinge loss and least absolute shrinkage and selection operator(LASSO)penalty are usually used in traditional ***,the hinge loss is not differentiable,and the LASSO penalty does not have the Oracle *** this paper,the huberized loss is combined with non-convex penalties to obtain a model that has the advantages of both the computational simplicity and the Oracle property,contributing to higher accuracy than traditional *** is experimentally demonstrated that the two non-convex huberized-SVM methods,smoothly clipped absolute deviation huberized-SVM(SCAD-HSVM)and minimax concave penalty huberized-SVM(MCP-HSVM),outperform the traditional SVM method in terms of the prediction accuracy and classifier *** are also superior in terms of variable selection,especially when there is a high linear correlation between the *** they are applied to the prediction of listed companies,the variables that can affect and predict financial distress are accurately filtered *** all the indicators,the indicators per share have the greatest influence while those of solvency have the weakest *** companies can assess the financial situation with the indicators screened by our algorithm and make an early warning of their possible financial distress in advance with higher precision.

关键词： Huberized loss Machine learning Non-convex penalties Support vector machine(SVM)

MiR-107-3p/Atp6v0e1 contributes to protective effects of two selenium-containing peptides,TSeMMM and SeMDPGQQ on lead-induced neurotoxicity

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Food Science and Human Wellness 2024年第4期13卷 2060-2067页

作者： Yong Fang Tianhang Huang Jian Wu Xieqi Luo Fengjiao Fan Peng Li Jian Ding Xinyang Sun College of Food Science and Engineering Nanjing University of Finance and Economics/Collaborative Innovation Center for Modern Grain Circulation and SafetyNanjing 210023China Laboratory of Neurodegenerative and Neuroinjury Diseases Wuxi School of MedicineJiangnan UniversityWuxi 214122China

Two selenium(Se)-containing peptides from Se-enriched rice,TSeMMM and SeMDPGQQ,possess neuroprotective potency against lead(Pb2+)-induced ***,the crosstalk between mRNA and microRNAs(miRNA)involved in the neuroprotection mechanism remains to be *** this study,RNA-sequencing and miRNA-sequencing were used to independently identify differentially expressed mRNAs and small RNAs profiles in Pb^(2+)-treated primary fetal rat cortical neurons and then the correlated miRNA-mRNA target pairs were *** was found that 34 mRNAs related to oxidative phosphorylation could be reversed by pretreatment of TSeMMM and *** protective effect of TSeMMM and SeMDPGQQ was mediated by upregulation of miR-107-3p,which downregulates the ATPase H+transporting V0 subunit e1(Atp6v0e1)mRNA level.A zebrafish model was applied to verify the relevance between the targeted mRNA and miRNA by real-time quantitative *** results indicated that miR-107-3p was a potential therapeutic target to achieve neuroprotection of Se-containing peptides via stimulation of Atp6v0e1.

关键词： Lead Se-containing peptides Neuroprotection miRNA

Cholesky GAS models for large time-varying covariance matrices

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Journal of Management Science and Engineering 2024年第1期9卷 115-142页

作者： Tingguo Zheng Shiqi Ye Department of Statistics and Data Science School of EconomicsXiamen UniversityXiamen361005China Wang Yanan Institute for Studies in economics Xiamen UniversityXiamen361005China Paula and Gregory Chow Institute for Studies in economics Xiamen UniversityXiamen361005China

This paper develops a new class of multivariate models for large-dimensional time-varying covariance matrices,called Cholesky generalized autoregressive score(GAS)models,which are based on the Cholesky decomposition of the covariance matrix and assume that the parameters are ***,two types of score-driven updates are considered:one is closer to the GARCH family,and the other is inspired by the stochastic volatility *** demonstrate that the models can be estimated equation-wise and are computationally feasible for high-dimensional ***,we design an equationwise dynamic model averaging or selection algorithm which simultaneously extracts model and parameter uncertainties,equipped with dynamically estimated model *** simulation results illustrate the superiority of the proposed ***,using a sizeable daily return dataset that includes 124 sectors in the Chinese stock market,two empirical studies with a small sample and a full sample are conducted to verify the advantages of our *** full sample analysis by a dynamic correlation network documents significant structural changes in the Chinese stock market before and after COVID-19.

关键词： Cholesky decomposition GAS Dynamic conditional correlations Dynamic model averaging

Wild Gibbon Optimization Algorithm

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Computers, Materials & Continua 2024年第7期80卷 1203-1233页

作者： Jia Guo JinWang Ke Yan Qiankun Zuo Ruiheng Li Zhou He Dong Wang Yuji Sato Hubei Key Laboratory of Digital Finance Innovation Hubei University of EconomicsWuhan430205China School of Information Engineering Hubei University of EconomicsWuhan430205China China Construction Third Engineering Bureau Installation Engineering Co. Ltd.Wuhan430074China Hubei Internet Finance Information Engineering Technology Research center Hubei University of EconomicsWuhan430205China College of Informatics Huazhong Agricultural UniversityWuhan430070China Faculty of Computer and Information Sciences Hosei UniversityTokyo184-8584Japan

Complex optimization problems hold broad significance across numerous fields and ***,as the dimensionality of such problems increases,issues like the curse of dimensionality and local optima trapping also *** address these challenges,this paper proposes a novel Wild Gibbon Optimization Algorithm(WGOA)based on an analysis of wild gibbon population *** two strategies:community search and community *** community search strategy facilitates information exchange between two gibbon families,generating multiple candidate solutions to enhance algorithm ***,the community competition strategy reselects leaders for the population after each iteration,thus enhancing algorithm *** assess the algorithm’s performance,CEC2017 and CEC2022 are chosen as test *** the CEC2017 test suite,WGOA secures first place in 10 *** the CEC2022 benchmark functions,WGOA obtained the first rank in 5 *** ultimate experimental findings demonstrate that theWildGibbonOptimization Algorithm outperforms others in tested *** underscores the strong robustness and stability of the gibbonalgorithm in tackling complex single-objective optimization problems.

关键词： Complex optimization wild gibbon optimization algorithm community search community competition

Quantifying the agreement and accuracy characteristics of four satellite-based LULC products for cropland classification in China

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Journal of Integrative Agriculture 2024年第1期23卷 283-297页

作者： Jie Xue Xianglin Zhang Songchao Chen Bifeng Hu Nan Wang Zhou Shi Department of Land Management Zhejiang UniversityHangzhou 310058China Institute of Applied Remote Sensing and Information Technology College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China ZJU-Hangzhou Global Scientific and Technological Innovation center Zhejiang UniversityHangzhou 311215China Department of Land Resource Management School of Public Finance and Public AdministrationJiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and economics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Spectroscopy Sensing Ministry of Agriculture and Rural AffairsHangzhou 310058China

Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing *** the differences in LULC classification schemes,there is a lack of research on assessing the accuracy of their application to croplands in a unified ***,this study evaluated the spatial and area accuracies of cropland classification for four commonly used global LULC products(i.e.,MCD12Q1V6,GlobCover2009,FROM-GLC and GlobeLand30)based on the harmonised FAO criterion,and quantified the relationships between four factors(i.e.,slope,elevation,field size and crop system)and cropland classification *** validation results indicated that MCD12Q1 and GlobeLand30 performed well in cropland classification regarding spatial consistency,with overall accuracies of 94.90 and 93.52%,*** FROMGLC showed the worst performance,with an overall accuracy of 83.17%.Overlaying the cropland generated by the four global LULC products,we found the proportions of complete agreement and disagreement were 15.51 and 44.72% for the cropland classification,*** consistency was mainly observed in the Northeast China Plain,the Huang-Huai-Hai Plain and the northern part of the Middle-lower Yangtze Plain,*** contrast,low consistency was detected primarily on the eastern edge of the northern and semiarid region,the Yunnan-Guizhou Plateau and southern *** size was the most important factor for mapping *** area accuracy,compared with China Statistical Yearbook data at the provincial scale,the accuracies of different products in descending order were:GlobeLand30,FROM-GLC,MCD12Q1,and *** cropland classification schemes mainly caused large area deviations among the four products,and they also resulted in the different ranks of spatial accuracy and area accuracy among the four *** results can provide valuable suggestions for selecting cropland products at the national or provinc

关键词： global LULC products cropland mapping accuracy evaluation food security China

Heat Shock Factor A1s are required for phytochrome-interacting factor 4-mediated thermomorphogenesis in Arabidopsis

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Journal of Integrative Plant Biology 2024年第1期66卷 20-35页

作者： Bingjie Li Shimeng Jiang Liang Gao Wenhui Wang Haozheng Luo Yining Dong Zhihua Gao Shuzhi Zheng Xinye Liu Wenqiang Tang Key Laboratory of Molecular and Cellular Biology of Ministry of Education Hebei Research Center of the Basic Discipline of Cell BiologyHebei Collaboration Innovation Center for Cell SignalingHebei Key Laboratory of Molecular and Cellular BiologyCollege of Life SciencesHebei Normal UniversityShijiazhuang 050024China School of Information Technology Hebei University of Economics and BusinessShijiazhuang 050061China

Thermomorphogenesis and the heat shock(HS)response are distinct thermal responses in plants that are regulated by PHYTOCHROME-INTERACTING FACTOR 4(PIF4)and HEAT SHOCK FACTOR A1s(HSFA1s),*** is known about whether these responses are interconnected and whether they are activated by similar *** analysis of transcriptome dynamics in response to warm temperature(28℃)treatment revealed that 30 min of exposure activated the expression of a subset of HSFA1 target genes in Arabidopsis ***,a loss-of-function HSFA1 quadruple mutant(hsfa1-cq)was insensitive to warm temperature-induced hypocotyl *** hsfa1-cq plants grown at 28℃,the protein and transcript levels of PIF4 were greatly reduced,and the circadian rhythm of many thermomorphogenesis-related genes(including PIF4)was ***,the nuclear localization of HSFA1s and the binding of HSFA1d to the PIF4 promoter increased following warm temperature exposure,whereas PIF4 overexpression in hsfa1-cq partially rescued the altered warm temperature-induced hypocotyl growth of the *** together,these results suggest that HSFA1s are required for PIF4 accumulation at a warm temperature,and they establish a central role for HSFA1s in regulating both thermomorphogenesis and HS responses in Arabidopsis.

关键词： HSFA1 PIF4 thermomorphogenesis

Shikimic acid accelerates phase change and flowering in Chinese jujube

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Horticultural Plant Journal 2024年第2期10卷 413-424页

作者： Xianwei Meng Zhiguo Liu Li Dai Weiqiang Zhao Jiurui Wang Lili Wang Yuanpei Cui Ying Li Yinshan Cui Yao Zhang Luyao Wang Fengjiao Yu Jin Zhao Mengjun Liu Research center of Chinese Jujube Hebei Agricultural UniversityBaodingHebei 071000China College of Horticulture Hebei Agricultural UniversityBaodingHebei 071000China College of Life Science Hebei Agricultural UniversityBaodingHebei 071000China College of Forestry Hebei Agricultural UniversityBaodingHebei 071000China eCollege of Economics and ManagementHebei Agricultural UniversityBaodingHebei 071000China College of economics and Management Hebei Agricultural University

The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like propert

关键词： Ziziphus jujuba Mill. Phase change Flowering Shikimic acid Transcriptome Metabolome

Risk assessment of oil and gas investment environment in countries along the Belt and Road Initiative

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Petroleum Science 2024年第2期21卷 1429-1443页

作者： Bao-Jun Tang Chang-Jing Ji Yu-Xian Zheng Kang-Ning Liu Yi-Fei Ma Jun-Yu Chen center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing100081China School of Management and economics Beijing Institute of TechnologyBeijing100081China Collaborative Innovation center of Electric Vehicles in Beijing BeijingChina Sustainable Development Research Institute for Economy and Society of Beijing BeijingChina Institute of Carbon Neutrality ShanghaiTech UniversityShanghai201210China

With the implementation of the Belt and Road Initiative, China is deepening its cooperation in oil and gas resources with countries along the Initiative. In order to better mitigate risks and enhance the safety of investments, it is of significant importance to research the oil and gas investment environment in these countries for China's overseas investment macro-layout. This paper proposes an indicator system including 27 indicators from 6 dimensions. On this basis, game theory models combined with global entropy method and analytic hierarchy process are applied to determine the combined weights, and the TOPSIS-GRA model is utilized to assess the risks of oil and gas investment in 76 countries along the Initiative from 2014 to 2021. Finally, the GM(1,1) model is employed to predict risk values for 2022-2025. In conclusion, oil and gas resources and political factors have the greatest impact on investment environment risk, and 12 countries with greater investment potential are selected through cluster analysis in conjunction with the predicted results. The research findings may provide scientific decisionmaking recommendations for the Chinese government and oil enterprises to strengthen oil and gas investment cooperation with countries along the Belt and Road Initiative.

关键词： Belt and Road Initiative Oil and Gas Investment Risk assessment