Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： The influence of different slope-facing environmental factors on the natural regeneration of Piceaschrenkiana in the middle section of the northern slope of Tianshan Mountains was investigated. A series of plotswere established on shady, semishady, semisunny, and sunny slopes at the same altitude, in a Picea schrenkianaforest to develop the structure equation model for the regeneration index which uses different slope- facingenvironmental factors. According to the environmental characteristics of the different slope- facings, therelationship between the survival status of Picea schrenkiana seedlings and environmental factors was analyzed.The results showed that the semishady and semisunny slopes were more suitable for the survival and growth ofseedlings, and the regeneration indexes of the two slopes (0.065 and 0.057) were significantly higher than thoseof the shady and sunny slopes. Litter was found to have a dual effect on the regeneration of Picea schrenkiana.The undecomposed litter layer was too thick to be beneficial to regeneration, while the rich organic matter couldpromote the formation of a high nitrogen environment in the soil, which was conducive to the regeneration ofseedlings. The influence of different slope-facing environmental factors on the regeneration index was in theorder of total nitrogen content (0.60) > adult tree density (0.46) > litter half- decomposed layer (0.37) > totalpotassium content (0.24) > organic matter content (0.23) > total phosphorus content ( − 0.16) > availablephosphorus content ( − 0.32) > litter undecomposed layer thickness ( − 0.34). Overall, the regeneration of Piceaschrenkiana seedlings in the region was best on the semishady and semisunny slopes with a closure degree ofapproximately 0.6 and litter thickness of approximately 2.5 cm, as well as high total nitrogen and total potassiumcontents in the soil.
Subjects: Astronomy >> Astronomical Instruments and Techniques submitted time 2022-03-15
Abstract：
High energy gamma-rays carry the fundamental information of the astrophysical sources in extreme conditions. The space detection of gamma-rays is distinguished by the wide energy range, the observation continuity as well as the high energy resolution. With the experience in constructing and running the DArk Matter Particle Explorer (DAMPE), we propose a new satellite mission——Very Large Area gamma-ray Space Telescope (VLAST). VLAST has an acceptance of ~10 m2·sr at GeV energies and ~ 1 m2·sr at MeV energies. Together with a much better energy resolution, VLAST is expected to increase the sensitivity of Fermi Large Area Telescope by a factor of 10. In this work, the main scientific objectives, the detection principle, the payload and the expected performance of VLAST are introduced.
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Peer Review Status:
Awaiting Review
Subjects: Biology >> Ecology submitted time 2018-05-18 Cooperative journals: 《生态学报》
Abstract：采矿及矿产品运输过程会对环境造成重金属污染进而对生物体产生危害。为定量描述艾维尔沟矿区道路两侧重金属污染程度、明确雪岭云杉叶片对重金属的吸收富集效应，通过采集雪岭云杉叶片和土壤样品，测试其铅（Pb）、锌（Zn）、镉（Cd）、砷（As）、铜（Cu）、铬（Cr）的含量，分析重金属的富集效应和空间分异特征。结果表明：（1）雪岭云杉叶片和土壤中各重金属含量差异显著（P P < 0.05），平均达86.28 μg/g，土壤中Zn、Cu超过了国家土壤质量标准的一级限制值，而As比三级限制值大41%；（2）以背景区（板房沟林场）的土壤和雪岭云杉叶片重金属为评价标准，研究区雪岭云杉叶片重金属综合污染指数为2.05，属中度污染，其中As和Pb单项污染指数较高，达3.65和2.57。研究区土壤重金属综合污染指数为1.69，属轻度污染；（3）随距离增加，除土壤和叶片中Pb含量表现为负线性递减外，As和Cu均表现为先升高后降低，土壤中Cr、Zn逐渐升高，但叶片中Cr逐渐降低，Zn变化不大；（4）冗余分析（RDA）结果显示土壤中Cu、As、Pb与雪岭云杉死树胸径和树高呈正相关关系，而Cr、Zn与其呈负相关。采矿及运输已对土壤和雪岭云杉的生长造成影响，本文对天山雪岭云杉森林的生态修复与保育具有一定的借鉴作用。
Subjects: Biology >> Bioengineering submitted time 2017-07-24 Cooperative journals: 《中国生物工程杂志》
Abstract： Abstract: object Separation and identification glycerol transporter in pichia pastoris (P. pastoris) and studying its function. Methods: In this study, the candidate glycerol transporter (gt1, GeneID: 8197545) was found in NCBI database by bioinformatics, and transmembrance structure was predicted by DAS. Targeted gene fused with egfp was cloned into pPICZ B and pRS424 to study its location in cells; recombinant plasmid (gt1+ pRS424) was transformed into Schizosaccharomyces pombe (S. pombe) to study its function; In order to study the relationship between gt1 and aox1, gt1 was deleted by homologous recombination, and enzyme activity of AOX1 in wild and mutant were detected. Results: According to results of bioinformatics, it was found that GT1 share the same transmembrance regions with sugar transporter 1( stl1) which has been identified as a glycerol transporter in Saccharomuces cerevisiae (S. cerevisiae), results of subcellular localization showed that GT1 located on membrance, S. pombe transformed into gt1 could growth on glycerol medium, but wild type could not, which suggested that GT1 could absorbed glycerol from medium to support cells growth. Moreover, AOX1 achieved constitutive expression in Δgt1. Conclusion: glycerol transporter (gt1) in P. pastoris was separated and identified, and its function in glycerol repression was preliminarily clarified.
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