1,091 research outputs found

    Self-Consistent MHD Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-Shaped Arcade Formation

    Full text link
    We performed magnetohydrodynamic simulation of coronal mass ejections (CMEs) and associated giant arcade formations, and the results suggested new interpretations of observations of CMEs. We performed two cases of the simulation: with and without heat conduction. Comparing between the results of the two cases, we found that reconnection rate in the conductive case is a little higher than that in the adiabatic case and the temperature of the loop top is consistent with the theoretical value predicted by the Yokoyama-Shibata scaling law. The dynamical properties such as velocity and magnetic fields are similar in the two cases, whereas thermal properties such as temperature and density are very different.In both cases, slow shocks associated with magnetic reconnectionpropagate from the reconnection region along the magnetic field lines around the flux rope, and the shock fronts form spiral patterns. Just outside the slow shocks, the plasma density decreased a great deal. The soft X-ray images synthesized from the numerical results are compared with the soft X-ray images of a giant arcade observed with the Soft X-ray Telescope aboard {\it Yohkoh}, it is confirmed that the effect of heat conduction is significant for the detailed comparison between simulation and observation. The comparison between synthesized and observed soft X-ray images provides new interpretations of various features associated with CMEs and giant arcades.Comment: 39 pages, 18 figures. Accepted for publication in the Astrophysical Journal. The PDF file with high resplution figures can be downloaded from http://www.kwasan.kyoto-u.ac.jp/~shiota/study/ApJ62426.preprint.pdf

    Lectures on the Asymptotic Expansion of a Hermitian Matrix Integral

    Full text link
    In these lectures three different methods of computing the asymptotic expansion of a Hermitian matrix integral is presented. The first one is a combinatorial method using Feynman diagrams. This leads us to the generating function of the reciprocal of the order of the automorphism group of a tiling of a Riemann surface. The second method is based on the classical analysis of orthogonal polynomials. A rigorous asymptotic method is established, and a special case of the matrix integral is computed in terms of the Riemann ζ\zeta-function. The third method is derived from a formula for the τ\tau-function solution to the KP equations. This method leads us to a new class of solutions of the KP equations that are \emph{transcendental}, in the sense that they cannot be obtained by the celebrated Krichever construction and its generalizations based on algebraic geometry of vector bundles on Riemann surfaces. In each case a mathematically rigorous way of dealing with asymptotic series in an infinite number of variables is established

    〔研究ノート〕Curriculum, Collaboration, and Coaching: A Multi-Faceted Approach to Study Abroad Preparation

    Get PDF
    The American College Readiness Track was created as part of an intensive English study abroad program in order to prepare female Japanese students for matriculation at universities that use English as the medium of instruction. This paper describes the specific goals of this academic track and the development of its curriculum using a backward design approach. The paper also explains the process used in selecting faculty to teach in the track, the professional development activities organized to prepare those faculty members for their assignments, and the ways in which the faculty collaborated to further develop and improve the track. In addition, the paper discusses the introduction of coaching into the American College Readiness Track. Coaching is defined, and its benefits are described. Cultural considerations, for example, the reinforcement of hierarchy inherent in the Japanese language and Japanese students' relative reticence in the classroom environment are also discussed in relation to their impact on the coaching process.departmental bulletin pape

    Functional representation of the Ablowitz-Ladik hierarchy

    Full text link
    The Ablowitz-Ladik hierarchy (ALH) is considered in the framework of the inverse scattering approach. After establishing the structure of solutions of the auxiliary linear problems, the ALH, which has been originally introduced as an infinite system of difference-differential equations is presented as a finite system of difference-functional equations. The representation obtained, when rewritten in terms of Hirota's bilinear formalism, is used to demonstrate relations between the ALH and some other integrable systems, the Kadomtsev-Petviashvili hierarchy in particular.Comment: 15 pages, LaTe

    Determinantal Characterization of Canonical Curves and Combinatorial Theta Identities

    Full text link
    We characterize genus g canonical curves by the vanishing of combinatorial products of g+1 determinants of Brill-Noether matrices. This also implies the characterization of canonical curves in terms of (g-2)(g-3)/2 theta identities. A remarkable mechanism, based on a basis of H^0(K_C) expressed in terms of Szego kernels, reduces such identities to a simple rank condition for matrices whose entries are logarithmic derivatives of theta functions. Such a basis, together with the Fay trisecant identity, also leads to the solution of the question of expressing the determinant of Brill-Noether matrices in terms of theta functions, without using the problematic Klein-Fay section sigma.Comment: 35 pages. New results, presentation improved, clarifications added. Accepted for publication in Math. An

    A Symmetric Generalization of Linear B\"acklund Transformation associated with the Hirota Bilinear Difference Equation

    Full text link
    The Hirota bilinear difference equation is generalized to discrete space of arbitrary dimension. Solutions to the nonlinear difference equations can be obtained via B\"acklund transformation of the corresponding linear problems.Comment: Latex, 12 pages, 1 figur

    Improvement in diastolic suction in patients with hypertrophic obstructive cardiomyopathy after septal ablation

    Get PDF
    Background: The ESMO Magnitude of Clinical Benefit Scale (ESMO-MCBS) version 1.0 (v1.0) was published in May 2015 and was the first version of a validated and reproducible tool to assess the magnitude of clinical benefit from new cancer therapies. The ESMO-MCBS was designed to be a dynamic tool with planned revisions and updates based upon recognition of expanding needs and shortcomings identified since the last review. Methods: The revision process for the ESMO-MCBS incorporates a nine-step process: Careful review of critiques and suggestions, and identification of problems in the application of v1.0; Identification of shortcomings for revision in the upcoming version; Proposal and evaluation of solutions to address identified shortcomings; Field testing of solutions; Preparation of a near-final revised version for peer review for reasonableness by members of the ESMO Faculty and Guidelines Committee; Amendments based on peer review for reasonableness; Near-final review by members of the ESMO-MCBS Working Group and the ESMO Executive Board; Final amendments; Final review and approval by members of the ESMO-MCBS Working Group and the ESMO Executive Board. Results: Twelve issues for revision or amendment were proposed for consideration; proposed amendments were formulated for eight identified shortcomings. The proposed amendments are classified as either structural, technical, immunotherapy triggered or nuanced. All amendments were field tested in a wide range of studies comparing scores generated with ESMO-MCBS v1.0 and version 1.1 (v1.1). Conclusions: ESMO-MCBS v1.1 incorporates 10 revisions and will allow for scoring of single-arm studies. Scoring remains very stable; revisions in v1.1 alter the scores of only 12 out of 118 comparative studies and facilitate scoring for single-arm studies

    Integrable equations in nonlinear geometrical optics

    Full text link
    Geometrical optics limit of the Maxwell equations for nonlinear media with the Cole-Cole dependence of dielectric function and magnetic permeability on the frequency is considered. It is shown that for media with slow variation along one axis such a limit gives rise to the dispersionless Veselov-Novikov equation for the refractive index. It is demonstrated that the Veselov-Novikov hierarchy is amenable to the quasiclassical DBAR-dressing method. Under more specific requirements for the media, one gets the dispersionless Kadomtsev-Petviashvili equation. Geometrical optics interpretation of some solutions of the above equations is discussed.Comment: 33 pages, 7 figure

    From Hurwitz numbers to Kontsevich-Witten tau-function: a connection by Virasoro operators

    Full text link
    In this letter,we present our conjecture on the connection between the Kontsevich--Witten and the Hurwitz tau-functions. The conjectural formula connects these two tau-functions by means of the GL()GL(\infty) group element. An important feature of this group element is its simplicity: this is a group element of the Virasoro subalgebra of gl()gl(\infty). If proved, this conjecture would allow to derive the Virasoro constraints for the Hurwitz tau-function, which remain unknown in spite of existence of several matrix model representations, as well as to give an integrable operator description of the Kontsevich--Witten tau-function.Comment: 13 page
    corecore