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Shrinking in the dark: Parallel endosymbiont genome erosions are associated with repeated host transitions to an underground life

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INSECT sciENCE 2024年第6期31卷 1810-1821页

作者： Beasley-Hall, Perry G. Kinjo, Yukihiro Rose, Harley A. Walker, James Foster, Charles S. P. Kovacs, Toby G. L. Bourguignon, Thomas Ho, Simon Y. W. Lo, Nathan univ Sydney Sch Life & Environm Sci Sydney NSW Australia univ Adelaide Sch Biol Sci Adelaide SA 5000 Australia okinawa inst sci & technol grad univ Evolutionary Genom Unit Onna Okinawa Japan Australian Govt Dept Agr Water & Environm Canberra Australia univ New South Wales Sch Comp Sci & Engn Sydney NSW Australia

Microbial symbioses have had profound impacts on the evolution of animals. Conversely, changes in host biology may impact the evolutionary trajectory of symbionts themselves. Blattabacterium cuenoti is present in almost all cockroach species and enables hosts to subsist on a nutrient-poor diet. To investigate if host biology has impacted Blattabacterium at the genomic level, we sequenced and analyzed 25 genomes from Australian soil-burrowing cockroaches (Blaberidae: Panesthiinae), which have undergone at least seven separate subterranean, subsocial transitions from above-ground, wood-feeding ancestors. We find at least three independent instances of genome erosion have occurred in Blattabacterium strains exclusive to Australian soil-burrowing cockroaches. These shrinkages have involved the repeated inactivation of genes involved in amino acid biosynthesis and nitrogen recycling, the core role of Blattabacterium in the host-symbiont relationship. The most drastic of these erosions have occurred in hosts thought to have transitioned underground the earliest relative to other lineages, further suggestive of a link between gene loss in Blattabacterium and the burrowing behavior of hosts. As Blattabacterium is unable to fulfill its core function in certain host lineages, these findings suggest soil-burrowing cockroaches must acquire these nutrients from novel sources. Our study represents one of the first cases, to our knowledge, of parallel host adaptations leading to concomitant parallelism in their mutualistic symbionts, further underscoring the intimate relationship between these two partners. Endosymbiotic bacteria live in the cells of other organisms. These microbes are particularly prevalent in insects, with whom they share a mutually beneficial relationship. In cockroaches, the endosymbiont Blattabacterium is vital for producing essential amino acids that hosts cannot acquire on their own. Soil-burrowing cockroaches of Australia are an interesting example in whic

关键词： Blattabacterium endosymbiosis gene loss molecular evolution parallel evolution subterranean habitats

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ON SYMMETRIC SCALAR CURVAURE ON S^2

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Chinese Annals of Mathematics,Series B 1999年第3期20卷 325-330页

作者： JI MIN(graduate School at Beijing, university of science and technology of China, Beijing 100039, China.)(Project supported by the National Natural science Foundation of China (No.19631050, No.19725102)and the Foundation of the Ministry of Education of Ch univ sci & technol China Grad Sch Beijing 100039 Peoples R China

Some new results are obtained for the problem of prescribing scalar curvature R on S2 when R possesses some kinds of symmetries.

关键词： Scalar curvature Symmetry Critical point Minimax method

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The Investigation of Oscillographic Chronopotentiometry at Silver Disk Electrode and Its Mechanism

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Chinese Chemical Letters 2000年第7期11卷 615-616页

作者： She Ying DONG Ke Qi YU Hong Sheng TANG Hong GAO(institute of Analytical science, Northwest university, Xi’an 710069graduate School, university of science & TecnoLogy of China, Beijing 100039) NW univ Xian Inst Analyt Sci Xian 710069 Peoples R China univ sci & technol China Grad Sch Beijing 100039 Peoples R China

A new method of oscillographic chronopotentiometry at silver disk electrode was investigated. By using it, a series of ions such as Pb, In, Cr, Tl, Bi etc. were determined. The detection limits are two or three orders of magnitude lower than those by oscillographic chronopotentiometry at mercury electrode. The proposed method is characterized by fine sensitivity, stable oscillogram and no mercury. The research on the mechanism of this method shows that these achievements are caused by the characterristics of silver electroxidation and electroreduction and the oscillographic chronopotentiometry (OC).

关键词： silver disk electrode oscillographic determination oscillographic chronopotentiometry

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ASYMPTOTIC NORMALITY OF PARAMETERSESTIMATION IN EV MODEL WITH REPLICATEDOBSERVATIONS

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Acta Mathematica scientia 2002年第1期22卷 107-114页

作者：张三国陈希孺 univ sci & technol China Grad Sch Beijing 100039 Peoples R China Chinese Acad sci Grad Sch Beijing 100039 Peoples R China

This paper based on the essay [1], studies in case that replicated observations are available in some experimental points., the parameters estimation of one dimensional linear errors-in-variables (EV) models. Asymptot... 详细信息

关键词： errors-in-variables model asymptotic normality replicated observations

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Special issue： Development of renewable energy and smart grid

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Frontiers in Energy 2017年第2期11卷 105-118页

作者： Schwarz, Harald Cai, Xiaoshu Brandenburg univ technol Cottbus Senftenberg Cottbus Germany univ Shanghai sci & technol Grad Sch Shanghai Peoples R China univ Shanghai sci & technol Coll Power Engn Shanghai Peoples R China

Germany,as well as China,conducted a variety of activities in the past decade to reduce CO2 in national power supply and strived to move to more renewable *** to geological differences in both countries,Germany established very fast a huge number of decentralized generation units from wind energy and *** from a technical point of view,these types of generation are highly fluctuating and not easily able to follow the power demand in the system minute by minute.

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A TOBIN-TYPE ESTIMATE OF CENSORED LINEAR MODELS

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Acta Mathematica scientia 1998年第4期18卷 361-370页

作者：陈希孺朱力行 univ sci & technol China Grad Sch Beijing 100039 Peoples R China Acad Sinica Inst Appl Math Beijing 100080 Peoples R China

The paper presents a two-stage method for estimating the parameters in the censored linear model Y-i = max(0, alpha(o) + X-i'beta(o)), 1 less than or equal to i less than or equal to n. In the first stage the data are grouped in some groups and then some adjustments are made, the results are used in the latter stage to form a Tobin-type estimate. The asymptotic normality of the estimate is proved and some simulations are made.

关键词： censoring linear models Tobin-type estimate

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Synthesis and characteristics of nitric oxide spin probes

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Chinese science Bulletin 1997年第20期42卷 1693-1699页

作者： Zhao, HT Liu, L Zhang, JZ Cong, JB Wu, K Sun, CP univ sci & technol China Grad Sch Dept Chem Beijing 100039 Peoples R China

NITRIC oxide (NO) is the important cell messenger molecule that regulates the central ner-vous, cardiovascular, endocrine and immunity systems. The study of NO not only canexplain many physiological phenomena, but also can provide new ways to prevent and treat alot of diseases. However, at present, most of the methods for assaying NO produced by or-ganism have some defects, for example, low sensitivity, no specificity, no convenience.

关键词： imidazole analogs nitrozide radical NO spin probe ESR.

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Conformal minimal two-spheres with constant Gauss curvature in U(3)

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Chinese science Bulletin 1998年第12期43卷 994-997页

作者： Jiao Xiaoxiang Peng Jiagui univ sci & technol China Grad Sch Dept Math Beijing 100039 Peoples R China

A complete classification of all conformal minimal 2-sphere with constant Gauss curvature is given in U(3).

关键词： conformal minimal Gauss curvature.

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THE RATES OF CONVERGENCE OF M-ESTIMATORS FOR PARTLY LINEAR MODELS IN DEPENDENT CASES

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Chinese Annals of Mathematics,Series B 1996年第3期17卷 317-324页

作者： LIU LUOFEI(Depatment of Mathematics, Jishou university, Hunan 416000, China) BEIJING univ DEPT PROBABIL & STATBEIJING 100871PEOPLES R CHINA univ sci & technol CHINA GRAD SCHBEIJING 100039PEOPLES R CHINA

The author proves several embedding theorems for finite covering maps, principal G-bundlesinto bundles. The main results are1. Let π: E→X be a finite covering mapt and X a connected locally pathconnectedparacompact space. If cat X≤5 k, then the finite covering space π: E→X can be embeddedinto the trivial real k-plane bundle.2. Let x: E→ X be a principal G-bundle over a paracompact space. If there exists alinear action of G on F (F = R or C) and cat X≤ k, then π: E→X can be embedded intofor any F-vector bundles ζi, i = 1,’’’ k.

关键词： Lusternik-Schnirelmann category Finite covering map Principal G-bundle

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Study on the Tribological Properties of Graphite-like Amorphous Carbon Film under Different Testing Conditions

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稀有金属材料与工程 2012年第S1期41卷 359-365页

作者： Wang Yongjun Li Hongxuan Ji Li Zhao Fei Liu Xiaohong Wu Yanxia Zhou Huidi Chen Jianmin Chinese Acad sci Lanzhou Inst Chem Phys State Key Lab Solid Lubricat Lanzhou 730000 Peoples R China Chinese Acad sci Grad Univ Beijing 100049 Peoples R China Henan univ sci & technol Sch Mat Sci & Engn Luoyang 471003 Peoples R China

Graphite-like amorphous carbon film was fabricated by unbalanced magnetron sputtering *** spectroscopy,atomic force microscopy(AFM)and tribometer were subsequently used to investigate the microstructure and tribological properties of the resultant *** is found that the deposited carbon film is dominated by sp 2 sites,and the intensity ratio of the D and G peaks is as high as 4.0,which is one order of magnitude larger than that of diamond-like carbon films with high sp 3 content,indicating a more graphite-like ***,the as-deposited carbon film exhibits moderately high hardness(13.7 GPa),low internal stress(0.38 GPa)and superior tribological properties with high load bearing capacity(Hertz contact stress about 3.2 GPa)and low wear rate(2.73×10-10 cm3/N.m)in ambient *** it displays a poor wear resistance in water lubricated condition,a superior wear resistance is achieved in oil lubricated *** inherent physical property,the formation of transfer layer and the friction induced chemical reactions may be commonly responsible for its tribological properties.

关键词： magnetron sputtering graphite-like carbon film microstructure tribological properties load bearing capacity

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