1,276 research outputs found

    New genera and species of leaf beetles (Coleoptera: Chrysomelidae) from China and South Korea

    Get PDF
    Two new genera from China (Taumaceroides Lopatin and Yunnaniata Lopatin) and 11 new species (Smaragdina quadrimaculata Lopatin, S. oblongum Lopatin, Hyphaenia volkovitshi Lopatin, Arthrotus daliensis Lopatin, Taumaceroides sinicus Lopatin, Yunnaniata konstantinovi Lopatin, Calomicrus yunnanus Lopatin, C. minutissimus Lopatin, Hermaeophaga belkadavi Konstantinov, H. dali Konstantinov from China, and H. korotyaevi Konstantinov from South Korea) are described and illustrated. A key to Hermaeophaga species of Eurasia is presented. Since Hermaeophaga dali was collected feeding on Paederia foetida L. (Rubiaceae), which is an invasive noxious weed in the United States, this species has potential as a biological control agent of this weed

    REVIEW OF THE LONGITARSUS ASPERIFOLIARUM GROUP OF SPECIES (COLEOPTERA: CHRYSOMELIDAE: ALTICINAE)

    Get PDF
    The Longitarsus asperifoliarum species group is reviewed. Four new species are de- scribed: L. hissaricus Lopatin, new species (Tadzhikistan), L. marguzoricus Konstanti- nov, new species (Tadzhikistan), L. tishechkini Konstantinov, new species (Kazakhstan), and L. violentoides Konstantinov, new species (Armenia). Longitarsus afghanicus Lo- patin is elevated to species status from its former status as L. asperifoliarum afghanicus. A key to the species and diagnostic characters for the group are provided. The setation of the apical and preapical abdominal tergites of females is recognized as a novel source of characters. Host plant and distributional data are included

    Semi-invariants of symmetric quivers of finite type

    Get PDF
    Let (Q,σ)(Q,\sigma) be a symmetric quiver, where Q=(Q0,Q1)Q=(Q_0,Q_1) is a finite quiver without oriented cycles and σ\sigma is a contravariant involution on Q0Q1Q_0\sqcup Q_1. The involution allows us to define a nondegenerate bilinear form on a representation $V$ of $Q$. We shall call the representation orthogonal if is symmetric and symplectic if is skew-symmetric. Moreover we can define an action of products of classical groups on the space of orthogonal representations and on the space of symplectic representations. For symmetric quivers of finite type, we prove that the rings of semi-invariants for this action are spanned by the semi-invariants of determinantal type cVc^V and, in the case when matrix defining cVc^V is skew-symmetric, by the Pfaffians pfVpf^V

    The H.E.S.S. central data acquisition system

    Full text link
    The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric Cherenkov Telescopes (IACTs) located in the Khomas Highland in Namibia. It measures cosmic gamma rays of very high energies (VHE; >100 GeV) using the Earth's atmosphere as a calorimeter. The H.E.S.S. Array entered Phase II in September 2012 with the inauguration of a fifth telescope that is larger and more complex than the other four. This paper will give an overview of the current H.E.S.S. central data acquisition (DAQ) system with particular emphasis on the upgrades made to integrate the fifth telescope into the array. At first, the various requirements for the central DAQ are discussed then the general design principles employed to fulfil these requirements are described. Finally, the performance, stability and reliability of the H.E.S.S. central DAQ are presented. One of the major accomplishments is that less than 0.8% of observation time has been lost due to central DAQ problems since 2009.Comment: 17 pages, 8 figures, published in Astroparticle Physic

    Cadaveric renal transplantation at the University of Pittsburgh: a two and one-half-year experience with the point system.

    Get PDF
    From January 1, 1986 to July 30, 1988, 530 consecutive cadaver kidney transplantations were performed with patient selection by a point system that took into account time awaiting an organ, donor-recipient matching, degree of presensitization, and some less important factors. The effect of the system was to diminish judgmental factors in case selection which in the past, had probably operated to the disadvantage of "undesirable" potential recipients, including older ones. Primary 1-year graft survival (74%) and graft survival after retransplantation (71%) were lower than in the earlier time. However, the results with triple-drug therapy using CsA, AZA and P demonstrated 88% 1-year graft survival for primary graft recipients and 74% in highly sensitized patients, with comparable patient mortality. These latter observations provide some assurance that the concepts of equitable access and efficient utilization of a scarce resource are not mutually exclusive

    Instanton approach to the Langevin motion of a particle in a random potential

    Full text link
    We develop an instanton approach to the non-equilibrium dynamics in one-dimensional random environments. The long time behavior is controlled by rare fluctuations of the disorder potential and, accordingly, by the tail of the distribution function for the time a particle needs to propagate along the system (the delay time). The proposed method allows us to find the tail of the delay time distribution function and delay time moments, providing thus an exact description of the long-time dynamics. We analyze arbitrary environments covering different types of glassy dynamics: dynamics in a short-range random field, creep, and Sinai's motion.Comment: 4 pages, 1 figur

    Generation of low-temperature plasma by low-pressure arcs for synthesis of nitride coatings

    Get PDF
    Experiments were performed to study gas, metal, and mixed metal-gas plasmas. The plasmas were generated with the use of an arc evaporator and a gas-plasma source with a hot filament and hollow cathode that were operated independently or simultaneously. It has been revealed that the arc current of gas-plasma source affects the parameters of the metal-gas plasma and the element concentrations in the coatings. It has been demonstrated that the characteristics of the nitride coatings produced by plasma-assisted vacuum-arc deposition can be controlled by varying the parameters of the arc in the gas-plasma source
    corecore