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A search for strongly Mg-enhanced stars from the Sloan Digital Sky Survey

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Research in Astronomy and Astrophysics 2014年第11期14卷 1423-1437页

作者： Xiang li Gang Zhao Yu-Qin Chen hai-ning li Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academyof Sciences University of Chinese Academy of Sciences

Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution （R≈2000） spectra from the Sloan Digital Sky Survey （SDSS） is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic （HRS） analysis by Nissen ＆ Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters （M92, M 13, M3, M71） which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.

关键词： stars abundance -- stars chemically peculiar -- method data analysis-- techniques spectroscopic analysis

Stellar mass estimation based on IRAC photometry for Spitzer SWIRE-field galaxies

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Research in Astronomy and Astrophysics 2010年第4期10卷 329-347页

作者： Yi-Nan Zhu Hong Wu hai-ning li Chen Cao National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Institute of Space Science and Physics Shandong University at Weihai Shandong 264209

We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey.We derived the formulae to calculate the stellar mass by using IRAC 3.6μm and 4.5μm luminosities.The massto-luminosity ratios of IRAC 3.6μm and 4.5μm luminosities are more sensitive to the star formation history of galaxies than to other factors,such as the intrinsic extinction,metallicity and star formation rate.To remove the effect of star formation history,we used g-r color to recalibrate the formulae and obtain a better result.Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae.Due to the emission from dust heated by the hottest young stars,luminous infrared galaxies present higher IRAC 4.5μm luminosities compared to IRAC 3.6μm luminosities.For most of type-Ⅱ AGNs,the nuclear activity cannot enhance 3.6μm and 4.5μm luminosities compared with normal galaxies.Star formation in our AGNhosting galaxies is also very weak,almost all of which are early-type galaxies.

关键词： galaxies：stellar content - galaxies：active - infrared：galaxies

Discovery of a strongly r-process enhanced extremely metal-poor star LAMOST J110901.22+075441.8

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Research in Astronomy and Astrophysics 2015年第8期15卷 1264-1274页

作者： hai-ning li Wako Aoki Satoshi Honda Gang Zhao Norbert Christlieb Takuma Suda Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences National Astronomical Observatory of Japan 2-21-1 OsawaMitakaTokyo181-8588Japan Department of Astronomical Science School of Physical SciencesThe Graduate University of Advanced Studies (SOKENDAI)2-21-1 OsawaMitakaTokyo 181-8588Japan University of Hyogo Center for AstronomyNishigaichiSayo-choSayoHyogo679-5313Japan Zentrum für Astronomie der Universitt Heidelberg LandessternwarteKnigstuhl 12D-69117 HeidelbergGermany Research Center for the Early Universe The University of TokyoHongo 7-3-1Bunkyo-kuTokyo 113-0033Japan

We report the discovery of an extremely metal-poor（EMP） giant,LAMOST J110901.22＋075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ～＋1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a highresolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22＋075441.8. The abundance pattern of LAMOST J110901.22＋075441.8 in the range of C through Zn is in line with the ＂normal＂ population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22＋075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern well.LAMOST J110901.22＋075441.8 provides the first detailed measurements of neutroncapture elements among r-II stars at such low metallicity with [Fe/H]-3.4, and exhibits similar behavior as other r-II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.

关键词： star： abundances—stars： PopulationⅡ— nucleosynthesis

High-α-Metal-Rich stars in the LAMOST-MRS survey and its connection with the galactic bulge

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Research in Astronomy and Astrophysics 2021年第6期21卷 424-432页

作者： Hao-Peng Zhang Yu-Qin Chen Gang Zhao Jing-Kun Zhao Xi-Long liang hai-ning li Ya-Qian Wu Ali Luo Rui Wang CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We report the detection of a large sample of high-α-metal-rich stars on the low giant branch with 2.60.2 than the comparison group.These properties strongly indicate its connection with the outer bar/bulge region at ... 详细信息

We report the detection of a large sample of high-α-metal-rich stars on the low giant branch with 2.6libration.A comparison group is selected to have a solarαratio at super metallicity,which is young and has a narrow age range around 3 Gyr.Both groups have thin-disk like kinematics but the former shows slightly large velocity dispersions.The special group shows a larger extension in a vertical distance toward 1.2 kpc,a second peak at smaller Galactic radius and a larger fraction of super metal rich stars with[Fe/H]>0.2 than the comparison group.These properties strongly indicate its connection with the outer bar/bulge region at R=3-5 kpc.A tentative interpretation of this special group is that its stars were formed in the X-shaped bar/bulge region,close to its corotation radius,where radial migration is the most intense,and brings them to present locations at 9 kpc and beyond.Low eccentricities and slightly outward radial excursions of its stars are consistent with this scenario.Its kinematics(cold)and chemistry([α/Fe]~0.1)further support the formation of the instability-driven X-shaped bar/bulge from the thin disk.

关键词： stars:late type stars:abundances stars:fundamental parameters Galaxy:disk Galaxy:evolution Galaxy:structure

Identification of WWTR1 as an immune infiltration-correlated prognostic biomarker in colon cancer

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Medical Data Mining 2022年第2期5卷 43-53页

作者： Jian-Shun Ge Jie Zhang Rui Wang hai-ning li Xin-Nong liu Xu-Dong Yin Yan-Bing Ding Guo-Tao Lu lin-lin Tian Institute of Digestive Diseases The Affiliated Hospital of Yangzhou UniversityYangzhou 225000China Department of General Surgery The Affiliated Hospital of Yangzhou UniversityYangzhou 225000China Department of Oncology The Affiliated Hospital of Yangzhou UniversityYangzhou 225000China Department of Gastroenterology The Affiliated Hospital of Yangzhou UniversityYangzhou 225000China Department of Oncology Dalian Medical UniversityDalian 116044China

WWTR1,a gene related to the TGF-βsignaling pathway,has been elucidated to be involved in oncogenesis in multiple studies.There is,however,no research on its link to immune infiltration in colon cancer.The TCGA database has identified WWTR1,a gene related to the TGF-βsignaling pathway,which is lowly expressed in colon cancer patients compared to normal subjects.Meanwhile,we produced the Kapan-Meier curve with GEO and the TCGA database,which revealed that colon cancer patients with high WWTR1 expression had a poor prognosis.We discovered that high expression of WWTR1 in colon cancer was associated with clinical stage,pathological T-stage,and lymphatic metastasis after examining the clinical characteristics of colon cancer patients.WWTR1 was found to be an independent predictive factor for colon cancer in a multivariate Cox regression study.Infiltration of immunological cells(B cells,CD8^(+)T cells,CD4^(+)T cells,Macrophage,Neutrophil,Dendritic cells)was linked to WWTR1 expression.In colon cancer,WWTR1 expression was also found to be favorably linked with major immune cell markers.According to an analysis of WWTR1 DCGs,GO,and KEGG enrichment analysis,WWTR1 expression levels were associated with ameboidal-type cell migration,focal adhesion,actin binding,Chemical carcinogenesis-reactive oxygen species,Non-alcoholic fatty liver disease,and Alzheimer disease.These findings imply that WWTR1 is a prognostically valuable and important biomarker for colon cancer,and imply that its expression is strongly linked to colon cancer immune infiltration,making it a potential new target for colon cancer biotherapy.

关键词： WWTR1 colon cancer The Cancer Genome Atlas Transforming growth factor-βsignaling immune infiltration prognosis

Automatic determination of stellar atmospheric parameters and construction of stellar spectral templates of the Guoshoujing Telescope (LAMOST)

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Research in Astronomy and Astrophysics 2011年第8期11卷 924-946页

作者： Yue Wu A-li Luo hai-ning li Jian-Rong Shi Philippe Prugniel Yan-Chun liang Yong-Heng Zhao Jian-Nan Zhang Zhong-Rui Bai Peng Wei Wei-Xiang Dong Hao-Tong Zhang Jian-Jun Chen National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Universitede Lyon Universite Lyon 1 Villeurbanne F-69622 France CRAL Observatoire de Lyon CNRS UMR 5574 69561 Saint-Genis Laval France Key Laboratory of Optical Astronomy NAOC Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Beijing 100049 China Shandong University at Weihai Weihai 264209 China

A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting the ULySS package, we have tested the effect of different resolutions and signal-to- noise ratios （SNR） on the measurement of the stellar atmospheric parameters （effective temperature Teff, surface gravity log g, and metaUicity [Fe/H]）. We show that ULySS is reliable for determining these parameters with medium-resolution spectra （R ～2000）. Then, we applied the method to measure the parameters of 771 stars selected in the commissioning database of the Guoshoujing Telescope （LAMOST）. The results were compared with the SDSS/SEGUE Stellar Parameter Pipeline （SSPP）, and we derived precisions of 167 K, 0.34dex, and 0.16dex for Teff, logg and [Fe/H] respectively. Furthermore, 120 of these stars are selected to construct the primary stellar spectral template library （Version 1.0） of LAMOST, and will be deployed as basic ingredients for the LAMOST automated parametrization pipeline.

关键词： astronomical data bases： atlases -- stars： fundamental parameters techniques： spectroscopic -- surveys

Searching for r-process-enhanced stars in the LAMOST surveyⅠ:the method

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Research in Astronomy and Astrophysics 2021年第2期21卷 89-96页

作者： Tian-Yi Chen Jian-Rong Shi Timothy CBeers Hong-liang Yan Qi Gao Chun-Qian li hai-ning li Gang Zhao CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Department of Physics and JINA Center for the Evolution of the Elements University of Notre DameNotre DameIN 46556USA

The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our Galaxy.To expand the sample of known r-process-enhanced stars,we have developed a method to search for candidates in the LAMOST medium-resolution(R7500)spectroscopic survey by matching the observed spectra to synthetic templates around the EuⅡline at 6645.1 A.We obtain a sample of 13 metal-poor(-2.35licity,using the strength of the BaⅡline at 6496.9 A.

关键词： stars abundances-stars chemically peculiar-stars statistics

Test observations that search for metal-poor stars with the Guoshoujing Telescope (LAMOST)

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Research in Astronomy and Astrophysics 2010年第8期10卷 753-760页

作者： hai-ning li Gang Zhao Norbert Christlieb A-li Luo Jing-Kun Zhao Yong-Heng Zhao Jian-Jun Chen Zhong-Rui Bai Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Zentrum fur Astronomie der Universitat Heidelberg Landessternwarte Konigstuhl 12 69117 Heidelberg Germany

Metal-deficient stars are regarded as fossils of the early generation of stars and therefore make crucial observational targets related to stellar astrophysics. They provide fundamental information and insights on properties of the very early stage of the chemical history of the Galaxy and have been investigated for decades. The unique design of the Guoshoujing Telescope （LAMOST）, such as its large field and multi-object observational capability, enables it to be an excellent tool for searching for these metal-poor stars in the Milky Way. This work reports the result of test observations which search for metal-poor stars with LAMOST, during which nine candidate metal-poor stars with [Fe/H] ≤ - 1.0 were newly detected based on the low-resolution spectroscopic observations of the LAMOST commissioning data. The sample of stars demonstrates the efficiency of selecting from the input catalog, as well as the ability of LAMOST to enlarge the sample of metal-poor stars in the Milky Way. Furthermore, the sample of stars could be used for future calibrations of the LAMOST stellar pa- rameter pipeline.

关键词： Galaxy stellar content -- surveys -- stars Population Ⅱ

太白山森林样地系统发育多样性格局及其影响因素

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Journal of Plant Ecology 2021年第1期14卷 96-107页

作者： Yong Xu Jia-Jia liu hai-ning li Juan liu Kevin S.Burgess Xue-Jun Geb Key Laboratory of Plant Resources Conservation and Sustainable Utilization South China Botanical GardenChinese Academy of SciencesGuangzhou 510650China University of Chinese Academy of Sciences Beijing 100049China School of Chinese Materia Medica Yunnan University of Chinese MedicineKunming 650500China College of Forestry Jiangxi Agriculture UniversityNanchang 310045China Department of Biology Columbus State UniversityUniversity System of GeorgiaColumbusGA 31907-5645USA Center of Conservation Biology Core Botanical GardensChinese Academy of SciencesGuangzhou 510650China

系统发育多样性指数常被用作区分植物群落构建过程中生态和演化过程的相对作用。系统发育多样性格局的推断方法(如系统树的构建和不同的系统发育多样性指数)、演化历史(如生活型)以及环境梯度都可能影响系统发育多样性格局的估计值,进... 详细信息

系统发育多样性指数常被用作区分植物群落构建过程中生态和演化过程的相对作用。系统发育多样性格局的推断方法(如系统树的构建和不同的系统发育多样性指数)、演化历史(如生活型)以及环境梯度都可能影响系统发育多样性格局的估计值,进而可能影响我们对植物群落构建过程的认知。因此,有必要区分这些因素如何作用于系统发育多样性格局的估计值,但其相对重要性及其交互作用仍不清楚。本研究利用位于太白山北坡沿海拔分布的20个森林样地(整体高差2800 m左右)的野外调查数据,包括274种木本植物和581种草本植物。对于上述样地内所有植物,我们构建了当前广泛采用的合成树和分子树以比较系统树的构建,特别是合成树末端的多歧分支结构,及其对系统发育多样性格局估计值的可能影响。同时,我们计算了每个样地的3种不同的系统发育多样性指数,包括Faithl PD,平均成对距离(MPD)和平均最近类群距离(MNTD),并分别对木本和草本植物进行计算。多模型比较分析系统发育多样性格局的估计值与系统树重建方法、多样性指数、生活型、海拔及其交互作用的最简约关系。研究结果表明,基于合成树和分子树所得到的系统发育多样性格局之间没有显著差异。海拔和多样性指数与生活型在解释系统发育多样性格局方面存在强烈的交互作用,并且能够解释44%以上的变异。系统发育多样性格局的估计值总体随海拔升高而降低,但草本植物相比木本植物变化更平缓。对于木本植物,3种系统发育多样性指数表现出一致的海拔分布格局(即系统发育聚集),而草本植物的平均成对距离指数则表现为随机的海拔分布格局。因此,分析沿环境梯度的系统发育多样性格局需要考虑系统发育格局的推断方法和演化历史的影响,以帮助我们更好地理解植物群落的构建过程。

关键词：群落构建海拔生活型多模型比较分析系统发育多样性系统发育重建太白山