检索结果-南通市图书馆

海南省玛瑙螺物种鉴定及其感染广州管圆线虫的调查

在线全文

学校读者我要写书评

暂无评论

热带医学杂志 2024年第4期24卷 480-485,489,I0002页

作者：高素真舒畅吕鑫焦惠生周云飞吕志跃海南医学院公共卫生学院海南海口571199 海南医学院基础医学与生命科学学院海南海口571199 中山大学中山医学院寄生虫学教研室广东广州510080

目的结合野外调查和实验室分析,了解海南现存玛瑙螺物种多样性及其携带广州管圆线虫的情况。方法采用分层随机抽样的调查方法,于2022年12月-2023年10月在海南省18个市县53个采样点采集玛瑙螺样本1060份,根据形态特征对样本进行初步鉴定... 详细信息

目的结合野外调查和实验室分析,了解海南现存玛瑙螺物种多样性及其携带广州管圆线虫的情况。方法采用分层随机抽样的调查方法,于2022年12月-2023年10月在海南省18个市县53个采样点采集玛瑙螺样本1060份,根据形态特征对样本进行初步鉴定,并取形态特征有差异的部分样本进行DNA提取和COI基因扩增,通过GenBank数据库内序列比对确定物种,并使用Mega 11软件构建进化树。同时采用肺检法和消化法了解其感染广州管圆线虫的情况并分析影响因素。结果在采集的1060份玛瑙螺样本中,通过形态学鉴定和分子鉴定确定海南存在两种玛瑙螺,其中褐云玛瑙螺占70.57%(748/1060),虎纹玛瑙螺占29.43%(312/1060)。形态学区分主要在胼胝部颜色上;分子鉴定显示,与褐云玛瑙螺处于同一支的样本,COI基因序列一致性在99.84%~100.00%;采集的未定种样本与虎纹玛瑙螺在同一进化分支上,COI基因一致性为90.75%~95.97%。二者与亲缘关系最近的物种间平均遗传距离分别为0.000~0.003和0.043~0.102。海南省玛瑙螺整体广州管圆线虫感染率为5.85%。褐云玛瑙螺和虎纹玛瑙螺的广州管圆线虫感染率分别为5.08%(38/748)和7.69%(24/312),差异无统计学意义(χ^(2)=2.728,P>0.05);二者感染度中位数分别为107.70条/g和37.32条/g,差异有统计学意义(Z=2.067,P0.05)。结论存在未定种玛瑙螺,高度疑似虎纹玛瑙螺,为岛内入侵物种玛瑙螺生物多样性提供相关研究依据。岛内玛瑙螺广州管圆线虫感染率无下降,但区域间感染率差异较大,防控措施应因地制宜。

关键词：玛瑙螺 COI基因广州管圆线虫

Two-Dimensional Fluid Simulation of Collisional Plasma Sheath over rf Powered electrode with Cylindrical Hole

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2004年第4期6卷 2404-2410页

作者：侯璐景王友年 Z.l.Miskvic State Key lab of Materials Modification by Beams Department of PhysicsDalian University of TechnologyDalian 116023China Department of Applied Mathematics University of WaterlooWaterlooOntarioCanada N2L 3G1he characteristics of collisional radio-frequency (rf) sheath dynamics over an elec-trode with a cylindrical hole is simulated by means of a self-consistent model which consists of two-dimensional time-dependent fluid equations coupled with Poisson equation. In addition an equivalent-circuit model is coupled to the fluid equations in order to self-consistently determine re-lationship between the instantaneous potential at the rf-biased electrode and the sheath thickness. Two-dimensional profiles of the potential the ion fluid velocity and the distributions of the ion and electron densities within the sheath are computed under various discharge conditions such as the discharge powers and the gas pressures. The results show that the existence of the cylindrical hole on the electrode significantly affects the sheath structure and generates a potential trap in the horizontal direction which is particularly strong when the sheath thickness is comparable to the depth of the hole. Moreover it is found that the collisional effects have a significant influence on the sheath characteristics.

The characteristics of collisional radio-frequency (rf) sheath dynamics over an elec-trode with a cylindrical hole is simulated by means of a self-consistent model which consists of two-dimensional time-dependent fluid equations coupled with Poisson equation. In addition, an equivalent-circuit model is coupled to the fluid equations in order to self-consistently determine re-lationship between the instantaneous potential at the rf-biased electrode and the sheath thickness. Two-dimensional profiles of the potential, the ion fluid velocity, and the distributions of the ion and electron densities within the sheath are computed under various discharge conditions, such as the discharge powers and the gas pressures. The results show that the existence of the cylindrical hole on the electrode significantly affects the sheath structure and generates a potential trap in the horizontal direction, which is particularly strong when the sheath thickness is comparable to the depth of the hole. Moreover, it is found that the collisional effects have a significant influence on the sheath characteristics.

关键词： two-dimensional sheath numerical simulation dusty plasma

Stability of a Variable Coefficient Star-Shaped Network with Distributed Delay

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2022年第6期35卷 2077-2106页

作者： ZHANG Hai-e XU Gen-Qi CHeN Hao lI Min School of Mathematics Tianjin UniversityTianjin 300350China Department of Basic Science Tangshan UniversityTangshan 063000China School of Mechatronical engineering Beijing Institute of TechnologyBeijing 100081China

The paper deals with the exponential stability problem of a variable coefficient star-shaped network,whose strings are coupled at a common end in a star-shaped configuration and the common connection of all strings can be *** kinds of media materials with a component of viscous and another simply elastic are distributed on each *** suitable hypothesis on the coefficient functionsμj(x)of damping terms and the kernelsηj(s)of distributed delay terms,the well-posedness of the system is obtained by means of resolvent family *** addition,the allocation proportion of the two parts and the property of the material character functions are discussed when the starshaped network is exponentially ***,the sufficient condition of exponential stability is *** simulations are also included to verify the main results.

关键词： Allocation proportion elastic and viscous exponential stability resolvent family starshaped network

A Survey of Human-centered Intelligent Robots:Issues and Challenges

在线全文

学校读者我要写书评

暂无评论

Ieee/CAA Journal of Automatica Sinica 2017年第4期4卷 602-609页

作者： Wei He Zhijun li C.l.Philip Chen Ieee School of Automation and electrical engineering University of Science and Technology Beijing College of Automation Science and engineering South China University of Technology Department of Computer and Information Science Faculty of Science and Technology University of Macao

Intelligent techniques foster the dissemination of new discoveries and novel technologies that advance the ability of robots to assist and support humans. The human-centered intelligent robot has become an important research field that spans all of the robot capabilities including navigation, intelligent control, pattern recognition and human-robot interaction. This paper focuses on the recent achievements and presents a survey of existing works on human-centered robots. Furthermore, we provide a comprehensive survey of the recent development of the human-centered intelligent robot and discuss the issues and challenges in the field.

关键词： Human-centered robots human-robot interaction intelligent control navigation path planning pattern recognition

Mediator Complex Dependent Regulation of Cardiac Development and Disease

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2013年第3期11卷 151-157页

作者： Chad e. Grueter Division of Cardiovascular Medicine Department of Internal Medicine University of Iowa Carver College of Medicine

Cardiovascular disease （CVD） is a leading cause of morbidity and mortality. The risk factors for CVD include environmental and genetic components. Human mutations in genes involved in most aspects of cardiovascular function have been identified, many of which are involved in transcriptional regulation. The Mediator complex serves as a pivotal transcriptional reg- ulator that functions to integrate diverse cellular signals by multiple mechanisms including recruit- ing RNA polymerase II, chromatin modifying proteins and non-coding RNAs to promoters in a context dependent manner. This review discusses components of the Mediator complex and the contribution of the Mediator complex to normal and pathological cardiac development and func- tion. enhanced understanding of the role of this core transcriptional regulatory complex in the heart will help us gain further insights into CVD.

关键词： Mediator complexCardiac disease Transcription Development

Chemically reactive and radiative von Kármán swirling flow due to a rotating disk

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(english edition) 2018年第9期39卷 1295-1310页

作者： M.KHAN J.AHMeD l.AHMAD Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan Department of Mathematics Shaheed Benazir Bhutto UniversitySheringal Upper Dir 18000Pakistan

A new mathematical model is presented to study the heat and mass transfer characteristics of magnetohydrodynamic(MHD) Maxwell fluid flow over a convectively heated stretchable rotating disk. To regulate the fluid temperature at the surface, a simple isothermal model of homogeneous-heterogeneous reactions is employed. The impact of nonlinear thermal radiative heat flux on thermal transport features is studied. The transformed nonlinear system of ordinary differential equations is solved numerically with an efficient method, namely, the Runge-Kutta-Felberg fourth-order and fifth-order(RKF45)integration scheme using the MAPle software. Achieved results are validated with previous studies in an excellent way. Major outcomes reveal that the magnetic flux reduces the velocity components in the radial, angular, and axial directions, and enhances the fluid temperature. Also, the presence of radiative heat flux is to raise the temperature of fluid. Further, the strength of homogeneous-heterogeneous reactions is useful to diminish the concentration of reaction.

关键词： rotating stretchable disk magnetic field nonlinear radiative heat flux homogeneous-heterogeneous chemical reaction

Neuronal avalanches:Sandpiles of self-organized criticality or critical dynamics of brain waves?

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2023年第4期18卷 337-348页

作者： Vitaly l.Galinsky lawrence R.Frank Center for Scientific Computation in Imaging University of California at San DiegoLa JollaCA 92037-0854USA Center for Functional MRI University of California at San DiegoLa JollaCA 92037-0677USA

Analytical expressions for scaling of brain wave spectra derived from the general nonlinear wave Hamiltonian form show excellent agreement with experimental“neuronal avalanche”*** theory of the weakly evanescent nonlinear brain wave dynamics[*** 2,023061(2020);*** Neurosci.32,2178(2020)]reveals the underlying collective processes hidden behind the phenomenological statistical description of the neuronal avalanches and connects together the whole range of brain activity states,from oscillatory wave-like modes,to neuronal avalanches,to incoherent spiking,showing that the neuronal avalanches are just the manifestation of the different nonlinear side of wave processes abundant in cortical *** a more broad way these results show that a system of wave modes interacting through all possible combinations of the third order nonlinear terms described by a general wave Hamiltonian necessarily produces anharmonic wave modes with temporal and spatial scaling properties that follow scale free power *** the best of our knowledge this has never been reported in the physical literature and may be applicable to many physical systems that involve wave processes and not just to neuronal avalanches.

关键词： nonlinear waves critical exponent Hamiltonian system neuronal avalanches critical dynamics

Cold plumes trigger contamination of oceanic mantle wedges with continental crust-derived sediments:evidence from chromitite zircon grains of eastern Cuban ophiolites

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第6期9卷 1921-1936页

作者： J.A.Proenza J.M.González-Jiménez A.Garcia-Casco e.Belousova W.l.Griffin C.Talavera Y.Rojas-Agramonte T.Aiglsperger D.Navarro-Ciurana N.Pujol-Solà F.Gervilla S.Y.O’Reilly D.e.Jacob Departament de Mineralogia Petrologia i Geologia AplicadaUniversitat de BarcelonaC/Martíi Franquès s/n08028BarcelonaSpain Departamento de Mineralogía y Petrología Universidad de GranadaFacultad de CienciasFuentenueva s/n 18002GranadaSpain Instituto Andaluz de Ciencias de la Tierra(CSIC-UGR) Avda.de las Palmeras 4E-18100ArmillaGranadaSpain ARC Centre of excellence for Core to Crust Fluid Systems(CCFS) GEMOC National Key CentreDepartment of Earth and Planetary SciencesMacquarie UniversitySydneyNSW 2109Australia John de laeter Centre Curtin UniversityPerthWA 6102Australia Geocycles-earth System Research Center Institut fur GeowissenschaftenJohannes Gutenberg-UniversitatBecherweg 21D-55099 MainzGermany Departamento de Geociencias Universidad de los AndesBogotáColombia

The origin of zircon grains, and other exotic minerals of typical crustal origin, in mantle-hosted ophiolitic chromitites are hotly debated. We report a population of zircon grains with ages ranging from Cretaceous(99 Ma) to Neoarchean(2750 Ma), separated from massive chromitite bodies hosted in the mantle section of the supra-subduction(SSZ)-type Mayari-Baracoa Ophiolitic Belt in eastern Cuba. Most analyzed zircon grains(n = 20, 287 ± 3 Ma to 2750 ± 60 Ma) are older than the early Cretaceous age of the ophiolite body, show negativeε_(Hf)(t)(-26 to-0.6) and occasional inclusions of quartz, K-feldspar,biotite, and apatite that indicate derivation from a granitic continental crust. In contrast, 5 mainly rounded zircon grains(297±5 Ma to 2126±27 Ma) show positive εHf(t)(+0.7 to +13.5) and occasional apatite inclusions, suggesting their possible crystallization from melts derived from juvenile(mantle)sources. Interestingly, younger zircon grains are mainly euhedral to subhedral crystals, whereas older zircon grains are predominantly rounded grains. A comparison of the ages and Hf isotopic compositions of the zircon grains with those of nearby exposed crustal terranes suggest that chromitite zircon grains are similar to those reported from terranes of Mexico and northern South America. Hence, chromitite zircon grains are interpreted as sedimentary-derived xenocrystic grains that were delivered into the mantle wedge beneath the Greater Antilles intra-oceanic volcanic arc by metasomatic fluids/melts during subduction processes. Thus, continental crust recycling by subduction could explain all populations of old xenocrystic zircon in Cretaceous mantle-hosted chromitites from eastern Cuba *** integrate the results of this study with petrological-thermomechanical modeling and existing geodynamic models to propose that ancient zircon xenocrysts, with a wide spectrum of ages and Hf isotopic compositions, can be transferred to the mantle wedge above subducting slabs by

关键词： Zircon U-Pb geochronology Chromitites Cold plumes Ophiolites Cuba

Floquet bands and photon-induced topological edge states of graphene nanoribbons

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 449-456页

作者： Weijie Wang Xiaolong lü Hang Xie College of Physics Chongqing UniversityChongqingChina

Floquet theorem is widely used in the light-driven systems. But many 2 D-materials models under the radiation are investigated with the high-frequency approximation, which may not be suitable for the practical experiment. In this work,we employ the non-perturbative Floquet method to strictly investigate the photo-induced topological phase transitions and edge states properties of graphene nanoribbons under the light irradiation of different frequencies(including both low and high frequencies). By analyzing the Floquet energy bands of ribbon and bulk graphene, we find the cause of the phase transitions and its relation with edge states. Besides, we also find the size effect of the graphene nanoribbon on the band gap and edge states in the presence of the light.

关键词： Floquet bands graphene topological phase transition edge states