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Momentum Effect Differs Across Stock Performances:Chinese Evidence

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Acta Mathematicae Applicatae sinica 2014年第2期30卷 279-288页

作者： Zhao-yuan LI si-bo LIU Mao-zai TIAN Department of Statistics and Actuarial Science The University of Hong Kong Department of Finance and Insurance Lingnan University Center for Applied Statistics School of StatisticsRenmin University of China School of Statistics Lanzhou University of Finance and Economics

Prior empirical studies find positive and negative momentum effect across the global nations, but few focus on explaining the mixed results. In order to address this issue, we apply the quantile regression approach to analyze the momentum effect in the context of Chinese stock market in this paper. The evidence suggests that the momentum effect in Chinese stock is not stable across firms with different levels of performance. We find that negative momentum effect in the short and medium horizon （3 months and 9 months） increases with the quantile of stock returns. And the positive momentum effect is observed in the long horizon （12 months）, which also intensifies for the high performing stocks. According to our study, momentum effect needs to be examined on the basis of stock returns. OLS estimation, which gives an exclusive and biased result, provides misguiding intuitions for momentum effect across the global nations. Based on the empirical results of quantile regression, effective risk control strategies can also be inspired by adjusting the proportion of assets with past performances.

关键词： chinese stock market investment strategy momentum effect quantile regression

Tumor angiogenesis and its clinical significance in pediatric malignant liver tumor

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World Journal of Gastroenterology 2005年第5期11卷 741-743页

作者： Xiao-YiSun zai-DeWu Xiao-FengLiao ji-YanYuan DepartmentofPediatricSurgery TongjiHospitalAffiliatedtoTongjiMedicalCollegeHuazhongUniversityofScienceandTechnologyWuhan430030HubeiProvinceChina

AIM: To investigate the expression of vascular endothelial growth factor (VEGF) and microvascular density (MVD) count in pediatric malignant liver tumor and their clinical significances. METHODS: Fourteen children with malignant liver tumors including seven hepatocellular carcinomas (HCCs), five hepatoblastomas, one malignant mesenchymoma and one rhabdomyosarcoma were studied. Twelve adult HCC samples served as control group. All samples were examined with streptavidin-biotin peroxidase (SP) immunohistochemical staining for VEGF expression and MVD count. RESULTS: VEGF positive expression in all pediatric malignant liver tumors was significantly higher than that in adult HCC (0.4971±0.14 vs0.4027±0.03, Psion in pediatric HCC group was also markedly higher than that in adult HCC group (0.5665±0.10 vs0.4027±0.03, Psignificantly higher than that in adult HCC (33.66±12.24 vs 26.52±4.38, Psignificantly higher compared to that in adult HCC group (36.94±9.28 vs 26.52±4.38, Psignificant difference compared to the pediatric non-HCC group (36.94±9.28 vs 30.37±14.61, P>0.05). All 7 children in HCC group died within 2 years, whereas the prognosis in pediatric non-HCC group was better, in which two patients survived more than 5 years. CONCLUsiON: Children with malignant liver tumors, especially with HCC, may have extensive angiogenesis that induces a rapid tumor growth and leads to a poor prognosis.

关键词： Liver tumor Angiogenesis Vascular endothelial growth factor Microvascular density

Fermi Blazars in the Zwicky Transient Facility Survey:Properties of Large Optical Variations

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Research in Astronomy and Astrophysics 2024年第10期24卷 104-115页

作者： si-si Sun Zhong-Xiang Wang Shun-Hao ji Department of Astronomy School of Physics and AstronomyYunnan UniversityKunming 650091China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

We analyze the optical light curve data,obtained with the Zwicky Transient Facility(ZTF)survey,for 47 γ-ray blazars monitored by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope(Fermi).These 47sources are selected because they are among the Fermi blazars with the largest optical variations in the ZTF *** color-magnitude variation patterns are seen in them,with one being redder-to-stable-when-brighter(RSWB;in 31 sources)and the other being stable when brighter(in 16 sources).The patterns fit with the results recently reported in several similar studies with different ***,we find that the colors in the stable state of the sources share similar values,for which(after being corrected for the Galactic extinction)most sources are in a range of 0.4–*** feature could be intrinsic and may be applied in,for example,study of the intragalactic *** also determine the turning points for the sources showing the RSWB pattern,after which the color changes saturate and become *** find a correlation between optical fluxes and γ-ray fluxes at the turning *** physical implications of the correlation remain to be investigated,probably better with a sample of high-qualityγ-ray flux measurements.

关键词： (galaxies:)BL Lacertae objects:general (galaxies:)quasars:general gamma-rays:galaxies

The Attractor of Fibonacci-like Renormalization Operator

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Acta Mathematica sinica,English Series 2020年第11期36卷 1256-1278页

作者： Hao Yang ji si Min LI School of Matherratical Sciences Uriversitgy of Science anad Technology of ChinaHefei 230026P.R.Chinra

In this paper we extend the Fibonacci-like maps to a wider class with the so-called“bounded combinatorics”.The Fibonacci-like renormalization operator R is defined and we showthat the orbit of each map from this cla... 详细信息

关键词： Fibonacci combinatorics principal nest renormalization

Time-Inconsistent Stochastic LQ Problem with Regime Switching

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Journal of Systems Science & Complexity 2020年第6期33卷 1733-1754页

作者： si Binbin NI Yuan-Hua ZHANG ji-Feng College of Artificial Intelligence Nankai UniversityTianjin 300350China Key Laboratory of IntelligentRobotics of Tianjin Tianjin 300350China Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy ofSciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper investigates a time-inconsistent stochastic linear-quadratic problem with regime switching that is characterized via a finite-state Markov ***-loop equilibrium control is studied in this paper whose existence is characterized via Markov-chain-modulated forward-backward stochastic difference equations and generalized Riccati-like equations with jumps.

关键词： Forward-backward stochastic difference equation open-loop equilibrium control regime switching stochastic linear-quadratic problem time inconsistency

Asymptotic Estimates to Non-global Solutions of a Multi-coupled Parabolic System

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Acta Mathematica sinica,English Series 2008年第10期24卷 1713-1726页

作者： Rui Hong ji si Ning ZHENG Department of Applied Mathematics Dalian University of Technology Dalian 116024 P. R. China

This paper deals with asymptotic behavior of solutions to a parabolic system, where two heat equations with inner absorptions are multi-coupled via inner sources and boundary flux. We determine four kinds of simultaneous blow-up rates under different dominations of nonlinearities in the model. Two characteristic algebraic systems associated with the problem are introduced to get very simple descriptions for the four simultaneous blow-up rates as well as the known critical exponents, respectively. It is observed that the blow-up rates are independent of the nonlinear inner absorptions.

关键词： simultaneous blow-up rates asymptotic estimates characteristic algebraic system multicoupled parabolic system non-global solution critical exponent

Supervised Vessels Classification Based on Feature Selection

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Journal of Computer Science & Technology 2017年第6期32卷 1222-1230页

作者： Bei-ji Zou Yao Chen Cheng-Zhang Zhu zai-Liang Chen Zi-Qian Zhang School of Information Science and Engineering Central South University Changsha 410083 China ‘Mobile Health' Ministry of Education-China Mobile Joint Laboratory Central South University Changsha 410083 China College of Literature and Journalism Central South University Changsha 410083 China

Arterial-venous classification of retinal blood vessels is important for the automatic detection of cardiovascular diseases such as hypertensive retinopathy and stroke. In this paper, we propose an arterial-venous classification （AVC） method, which focuses on feature extraction and selection from vessel centerline pixels. The vessel centerline is extracted after the preprocessing of vessel segmentation and optic disc （OD） localization. Then, a region of interest （ROI） is extracted around OD, and the most efficient features of each centerline pixel in ROI are selected from the local features, grey-level co-occurrence matrix （GLCM） features, and an adaptive local binary patten （A-LBP） feature by using a max-relevance and min-redundancy （mRMR） scheme. Finally, a feature-weighted K-nearest neighbor （FW-KNN） algorithm is used to classify the arterial-venous vessels. The experimental results on the DRIVE database and INSPIRE-AVR database achieve the high accuracy of 88.65% and 88.51% in ROI, respectively.

关键词： fundus image arterial-venous classification adaptive local binary patten(A-LBP) feature selection feature-weighted K-nearest neighbor(FW-KNN)

Changes in bacterial community and abundance of functional genes in paddy soil with cry1Ab transgenic rice

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Journal of Integrative Agriculture 2021年第6期20卷 1674-1686页

作者： SONG Ya-na CHEN zai-jie WU Ming-ji LI Gang WANG Feng Institute of Biotechnology Fujian Academy of Agricultural Sciences/Fujian Provincial Key Laboratory of Genetic Engineering for AgricultureFuzhou 350003P.R.China

A field experiment involving cry1Ab transgenic rice(GM) and its parental non-cry1Ab rice(M) has been on-going since 2014. The diversity of the bacterial communities and the abundance of the microbial functional genes which drive the conversion of nitrogen in paddy soil were analyzed during the growth period of rice in the fifth year of the experiment, using 16 S rRNAbased Illumina Mi Seq and real-time PCR on the amoA, nirS and nirK genes. The results showed no differences in the alpha diversity indexes of the bacterial communities, including Chao1, Shannon and simpson, between the fields cultivated with line GM and cultivar M at any of the growth stages of rice. However, the bacterial communities in the paddy soil with line GM were separated from those of paddy soil with cultivar M at each of the growth stages of rice, based on the unweighted Uni Frac NMDS or PCoA. In addition, the analyses of ADONIS and ANOsiM, based on the unweighted Uni Frac distance, indicated that the above separations between line GM and cultivar M were statistically significant(Psignificantly increased(Psition of bacterial communities or the abundance of microbial functional genes in the paddy soil.

关键词： cry1Ab transgenic rice bacterial community microbial functional gene Illumina MiSeq Platform real-time PCR

Cage Clusters: from Structure Prediction to Rational Design of Functional Nanomaterials

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Chinese Journal of Structural Chemistry 2020年第7期39卷 1185-1193页

作者： ZHOU si ZHAO Yan-Yan ZHAO ji-Jun Key Laboratory of Materials Modification by Laser Ion and Electron Beams Dalian University of TechnologyMinistry of EducationDalian 116024China

Atomic clusters of subnanometer scale and variable chemical composition offer great opportunities for rational design of functional *** them,cage clusters doped with endohedral atom are particularly interesting owing to their enhanced stability and highly tunable physical and chemical *** this perspective,first we give a brief overview of the history of doped cage clusters and introduce the home-developed comprehensive genetic algorithm(CGA)for structure prediction of ***,we show a few examples of magnetic clusters and subnanometer catalysts based on doped cage clusters,which are computationally revealed or designed by the CGA ***,we give an outlook for some future directions of cluster science.

关键词： cluster genetic algorithm magnetism subnanometer catalysts