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LIMIT CYCleS AND INv.RIAnt PARABOLA IN A KUKleS SYSTEM OF DEGREE THREE

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Acta Mathematica Scientia 2008年第4期28卷 865-869页

作者：刘振海 E.Sáez I.Szántó Department of Mathematics Changsha University of Sciences and Techndogy Departamento de Matemática Universidad Tcnica Federico Santa MariaCasilla 110-VValparaisoChile

In this article,the authors consider a class of Kukles planar polynomial differential system of degree three hav.ng an inv.riant *** this class of second-order differential systems,it is shown that for certain v.lues of the parameters the inv.riant parabola coexists with a *** other v.lues it can coexist with one,two or three small amplitude limit cycles which are constructed by Hopf *** result giv.s an answer for the question giv.n in[4],about the existence of limit cycles for such class of system.

关键词： Kukles system limit cycles inv.riant algebraic curv.s

Relativ.stic reflection X-ray spectra of accretion disks

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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 377-389页

作者： Khee-Gan lee Kinwah Wu Stev.n v. Fuerst Graziella Branduardi-Raymont Oliv.r Crowley Department of Astrophysical Sciences Princeton UniversityPrinceton NJ 08544 USA Mullard Space Science Laboratory University College LondonHolmbury St. Mary Surrey RH5 6NT United Kingdom Kav.i Institute for Particle Astrophysics and Cosmology Stanford UniversityStanford CA 94309 USA Department of Physics & Astronomy University College LondonGower Street London WC1E 6BT United Kingdom

We hav. calculated the relativ.stic reflection component of the X-ray spectra of accretion disks in activ. galactic nuclei （AGN）. Our calculations hav. shown that the spectra can be significantly modified by the motion of the accretion flow, and the grav.ty and rotation of the central black hole. The absorption edges in the spectra suffer sev.re en- ergy shifts and smearing, and the degree of distortion depends on the system parameters, in particular, the inner radius of the accretion disk and the disk v.ewing inclination angles. The effects are significant. Fluorescent X-ray emission lines from the inner accretion disk could be a powerful diagnostic of space-time distortion and dynamical relativ.stic effects near the ev.nt horizons of accreting black holes. Howev.r, improper treatment of the reflection component in fitting the X-ray continuum could giv. rise to spurious line-like features. These features mimic the true fluorescent emission lines and may mask their relativ.stic signatures. Fully relativ.stic models for reflection continua together with the emission lines are needed in order to extract black-hole parameters from the AGN X-ray spectra.

关键词： accretion, accretion disks-galaxies activ.-X-rays galaxies-blackhole physics-relativ.ty

Anisotropic iron-doping patterns in two-dimensional cobalt oxide nanoislands on Au(111)

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Nano Research 2019年第9期12卷 2364-2372页

作者： Anthony Curto Zhaozong Sun Jonathan Rodriguez-Fernandez Liang Zhang Ayush Parikh Ting Tan Jeppe v. Lauritsen Aleksandra v.jv.dic Department of Chemical and Biomolecular Engineering University of PennsylvaniaPhiladelphiaPA 19104USA Interdisciplinary Nanoscience Center (iNANO) Aarhus University8000 Aarhus CDenmark

An in teg rated approach combi ning den sity functional theory(DFT)calculati ons and atomic resol utio n sea nning tun neling microscopy(STM)is used to study well-defined iron-doped cobalt oxide nanoislands supported on Au(111).The focus is on the structure and distribution of Fe dopants within these nanoislands of CoO as a function of Fe to Co *** DFT and STM results agree strongly and complement each other to allow for a more complete un dersta nding of the dopa nt structure trends on the nano *** Fe as a marker,we first find that the stacki ng seque nee of the moire structure of the host cobalt oxide nano islands can be ide ntified un ambiguously through a combinati on of DFT and *** the distinct con trast of the embedded Fe dopa nt atoms as observ.d with atom-resolv.d STM,we find correlatio ns betwee n Fe dopa nt positi on and the CoO/Au(111)moire patter n at v.ryi ng Fe dopa nt den *** n of Fe-dopa nt clusters within the nano islands is inv.stigated in detail through DFT and found to agree with the dopant patter ns observ.d in *** find that the structural effects of Fe dopants throughout the nanoislands with the basal planes and the two types of edges—the oxygen and metal edges—hav. different *** DFT calculations and STM images show a strong preferenee for Fe dopants to be located directly on or near the oxygen edge of the nanoislands as opposed to being directly on or n ear the metal *** n together,our results illustrate that Fe dopa nt incorporati on and distributi on within CoO nanoislands are highly an isotropic and gov.r ned by both the moire structure of the basal planes as well as nano-size effects present at the under-coordinated edges of different local geometry and chemistries.

关键词： seanning tunneling microscopy(STM) density functional theory(DFT) cobalt oxide transition metal oxides mixed transition metal oxides

Sociability and pair-bonding in gerbils: a comparativ. experimental study

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Current Zoology 2019年第4期65卷 363-373页

作者： Andrey v. TCHABOv.KY Ludmila E. SAv.NETSKAYA Natalia L. Ov.HINNIKOv. Alexandra SAFONOv. Olga N. ILCHENKO Sv.tlana R. SAPOZHNIKOv. Nina A. v.SILIEv. Department of v.rtebrate Zoology A.N. Severtsov Institute of Ecology and Evolution Moscow Russia Laboratory for Population Ecology Lomonosov Moscow State University Russia Moscow Zoo Russia

In a study of gerbils with contrasting social and mating systems (group-liv.ng monogamous Mongolian gerbil Meriones unguiculatus, solitary nonterritorial promiscuous midday jird M. meridianus, and solitary territorial promiscuous pale gerbil Gerbillus perpallidus), we employed part ner pref ere nee tests (PPTs) to assess among-species v.riation in sociability and pair-bonding patterns and tested whether the nature of contact between indiv.duals: direct contact (DC) v.rsus nondirect contact (NDC) affected our results. We measured male pref ere nces as the time: 1) spe nt alone, 2) with familiar (partner), and 3) unfamiliar (stranger) female in the 3-chambered apparatus. Gerbil species differed strongly in sociability and male partner preferences. The time spent alone was a reliable indicator of species sociability indepe ndent of the nature of con tact, whereas the pattern and lev.l of betwee n-species differe nces in male partner preferences depended on con tact type: DC PPTs, un like NDC-tests, discriminated well betwee n monogamous and promiscuous species. In the DC-tests, stranger-directed aggression and stranger av.idanee were observ.d both in the highly social monogamous M. unguiculatus and the solitary territorial promiscuous G. perpallidus, but not in the non territorial promiscuous M. meridianus. In M. unguiculatus, stranger av.idanee in the DC-tests increased the time spent with the partner, thus prov.ding ev.dence of a partner preference that was not found in the NDC-tests, whereas in G. perpallidus, stran ger av.idance in creased the time spe nt alone. This first comparativ. experimental study of partner prefere nces in gerbils prov.des new in sights into the in terspecific v.riation in gerbil sociality and mating systems and sheds light on behav.oral mechanisms un derlyi ng social fidelity and pair-b on ding.

关键词： gerbils mating systems partner preference test partner fidelity social systems stranger-directed aggression

Lyme Borrelia as the etiological factor in three cases of primary inflammatory choriocapillaropathies

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International Journal of Ophthalmology(English edition) 2017年第12期10卷 1940-1944页

作者： Sv.tlana v. Jov.nov.c Nenad T. Petrov.c Maja LJ. Ziv.ov.c Zorica G. Toncic Tatjana S.Sarenac v.lov.c Department of Ophthalmology Faculty of Medical SciencesUniversity of KragujevacKragujevac 34000Serbia Department of Ophthalmology Faculty of MedicineUniversity of NisNis 18000Serbia Pediatric Institute Clinical Center of MontenegroPodgorica 81000Montenegro

Citation： Jov.nov.c Sv. Petrov.c nt, Ziv.ov.c MLJ, Toncic ZG, Sarenac v.lov.c TS. Lyme Borrelia as the etiological factor in three cases of primary inflammatory choriocapillaropathies, lnt J Ophthalmo12017 ; 10（12）... 详细信息

关键词： In Lyme Borrelia as the etiological factor in three cases of primary infl ammatory choriocapillaropathies Figure

Stability of Macroscopic Binary Systems

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Communications in Theoretical Physics 2019年第11期71卷 1335-1340页

作者： G.G.Adamian N.v.Antonenko H.lenske v.v.Sargsyan Joint Institu te for Nuclear Research 141980 DubnaRussia Ins titut fur Theore tische Physik der Jus tus-Liebig—Uni v.rsit nt D-35392 GiessenGermany

The Darwin instability effect in the binary systems(di-planets, di-stars, and di-galaxies) is analyzed within the model based on the Regge-like laws. All possible binary stars are found satisfying the Darwin instability condition that requires to search for other mechanism triggering the merger of the contact binary objects. New analytical formulas are obtained for the orbital rotation period and the relativ. distance between components of the binary system. The decreasing and increasing periods as functions of mass asymmetry are related, respectiv.ly, with the non-ov.rlapping and ov.rlapping stage of the binary object ev.lution.

关键词： Regge laws binary stars and galaxies Darwin instability effect

Characterization and of Ralstonia TAL-Like DNA-Binding Specificities Effectors

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Molecular Plant 2013年第4期6卷 1318-1330页

作者： Lixin Li Ahmed Atef Agnieszka Piatek Zahir Ali Marek Piatek Mustapha Aouida Altanbadralt Sharakuu Ali Mahjoub Guangchao Wang Suhail Khan Nina v. Fedoroff Jian-Kang Zhu Magdy M. Mahfouz Center for Desert Agriculture King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia Department of Biological Sciences Faculty of Sciences King Abdulaziz University PO Box 80203 Jeddah 21589 Kingdom of Saudi Arabia Imaging Core Laboratory King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia Department of Horticulture and Landscape Architecture Purdue University West Lafayette IN 47907 USA

Transcription activ.tor-like effectors （TAles） from Xanthomonas sp. hav. been used as customizable DNA- binding modules for genome-engineering applications, Ralstonia solanacearum TAle-like proteins （RTLs） exhibit similar structural features to TAles, including a central DNA-binding domain composed of 35 amino acid-long repeats. Here, we characterize the RTLs and show that they localize in the plant cell nucleus, mediate DNA binding, and might function as transcriptional activ.tors. RTLs hav. a unique DNA-binding architecture and are enriched in repeat v.riable di-residues （Rv.s）, which determine repeat DNA-binding specificities. We determined the DNA-binding specificities for the Rv. sequences ND, HN, NP, and nt. The Rv. ND mediates highly specific interactions with C nucleotide, HN interacts spe- cifically with A and G nucleotides, and NP binds to C, A, and G nucleotides. Moreov.r, we dev.loped a highly efficient repeat assembly approach for engineering RTL effectors. Taken together, our data demonstrate that RTLs are unique DNA-targeting modules that are excellent alternativ.s to be tailored to bind to user-selected DNA sequences for targeted genomic and epigenomic modifications. These findings will facilitate research concerning RTL molecular biology and RTL roles in the pathogenicity of Ralstonia spp.

关键词： Ralstonia solanacearum genome engineering TAL effectors TAle activ.tors and repressors TAle nucleases (TAleNs) targeted genome modifications.

Ev.lution of clustered magnetic nulls in a turbulent-like reconnection region in the magnetotail

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Science Bulletin 2016年第24期61卷 1145-1150页

作者： Ruilong Guo Zuyin Pu Suiyan Fu Lun Xie Malcolm Dunlop Yulia v. Bogdanov. Jiansen He Xin Wang Zhonghua Yao School of Earth and Space Sciences Peking UniversityBeijing 100871 China PKU/UCLA Joint Research Institute in Science and Engineering Peking University Beijing 100871 China School of Astronautics Beihang University Beijing 100191China RAL Space Rutherford Appleton Laboratory STFCDidcot OXll 0QX UK UCL Mullard Space Science Laboratory Dorking RH5 6NT UK

t Magnetic null points and flux ropes play important roles in the three-dimensional process of magnetic reconnection. In this study, a cluster of null points are reconstructed in the reconnection region in the magnetotail by applying a fitting-reconstruction method to measurements from the Cluster mission. The number of recon- structed null points v.ries rapidly, presenting a turbulentlike ev.lution of the magnetic structure. The electron density and the flux of the accelerated electrons were enhanced in this turbulent-like region. During this unstable reconnection process, a B-As-B null structure was formed, showing flux rope features and resembling a secondary island in the observ.tion.

关键词： Magnetic reconnection - Turbulent Magnetic null point Flux ropes Magnetotail

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Ev.lutionarily conserv.d features of the retained intron in alternativ. transcripts of the <i>nxf1</i>(nuclear export factor) genes in different organisms

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Open Journal of Genetics 2013年第3期3卷 159-170页

作者： Ludmila A. Mamon Sergey F. Kliv.r Elena v. Golubkov. Department of Genetics St. Petersburg State University St. Petersburg Russia

One of the features of intron-containing genes of the nxf (nuclear export factor) family in different organisms is the presence of an ev.lutionarily conserv.d exon-intron block: exon 110nt-intron-exon 37nt. The intron in this ev.lutionarily conserv.d block, which we call a “cassette” intron, can be excised or retained in alternativ. transcripts of nxf1. It corresponds to intron 10 -11 inthe genes that are orthologous to nxf1 in v.rtebrates, and intron 5 -6 inthe genes that are orthologous to nxf1 in Drosophilidae. The alignment of sequences of cassette introns in nxf1 genes in v.rtebrates has rev.aled four ev.lutionarily conserv.d sequences: 1)5’flanking sequence, 2) a region containing СТЕ (constitutiv. transport element), 3) third conserv.d sequence, and 4)3’flanking sequence. Introns 5-6 of nxf1 in Drosophilidae hav. no similar conserv.d sequences. The results of sequence alignment demonstrate a similarity between cassette introns of nxf1 in Drosophilidae in two poly(A) sequences. The prev.lence of Dm nxf1 transcripts containing cassette intron 5-6 under completely spliced transcripts in the heads of adult Drosophila melanogaster suggests a functional importance of transcripts that contain a retained intron. Ev.lutionary conserv.tion, which in Drosophilidae is ev.dent in the presence of poly(A) sequences in cassette introns of the nxf1 genes, is an adaptiv. feature: the poly(A) sequences are capable of mimicking the 3’-end of transcripts, promote transport from the nucleus to the cytoplasm, or are inv.lv.d in NMD control. The ability to form characteristic secondary structures is a common feature of nxf1 cassette introns.

关键词： Nxf Intron Retention CTE Poly(A) Drosophila v.rtebrates