18,801 research outputs found

    Twisted algebra R-matrices and S-matrices for bn(1)b_n^{(1)} affine Toda solitons and their bound states

    Full text link
    We construct new Uq(a2n1(2))U_q(a^{(2)}_{2n-1}) and Uq(e6(2))U_q(e^{(2)}_6) invariant RR-matrices and comment on the general construction of RR-matrices for twisted algebras. We use the former to construct SS-matrices for bn(1)b^{(1)}_n affine Toda solitons and their bound states, identifying the lowest breathers with the bn(1)b^{(1)}_n particles.Comment: Latex, 24 pages. Various misprints corrected. New section added clarifying relationship between R-matrices and S-matrice

    Pattern Formation in Semiconductors

    Get PDF
    In semiconductors, nonlinear generation and recombination processes of free carriers and nonlinear charge transport can give rise to non-equilibrium phase transitions. At low temperatures, the basic nonlinearity is due to the autocatalytic generation of free carriers by impact ionization of shallow impurities. The electric field accelerates free electrons, causing an abrupt increase in free carrier density at a critical electric field. In static electric fields, this nonlinearity is known to yield complex filamentary current patterns bound to electric contacts

    Electron-positron momentum distributions and positron lifetime in semiconductors in the generalized gradient approximation

    Get PDF
    The positron annihilation characteristics have been calculated taking the electron-positron correlation in the generalized gradient approximation (GGA). The calculated electron-positron momentum distributions in Si along the [110] direction in the GGA scheme agree very well with the experiment. The comparison of anisotropies of the momentum distributions along different crystal directions with the theory shows that only the GGA scheme gives the exact values. The enhancement factor for the valence electrons in the electron-positron momentum density is found to be weakly dependent on the momentum. The positron lifetimes in group IV, III-V, and II-VI semiconductors agree very well with the previous calculations and the experiment.published_or_final_versio

    Cell sorting in a Petri dish controlled by computer vision.

    Get PDF
    Fluorescence-activated cell sorting (FACS) applying flow cytometry to separate cells on a molecular basis is a widespread method. We demonstrate that both fluorescent and unlabeled live cells in a Petri dish observed with a microscope can be automatically recognized by computer vision and picked up by a computer-controlled micropipette. This method can be routinely applied as a FACS down to the single cell level with a very high selectivity. Sorting resolution, i.e., the minimum distance between two cells from which one could be selectively removed was 50-70 micrometers. Survival rate with a low number of 3T3 mouse fibroblasts and NE-4C neuroectodermal mouse stem cells was 66 +/- 12% and 88 +/- 16%, respectively. Purity of sorted cultures and rate of survival using NE-4C/NE-GFP-4C co-cultures were 95 +/- 2% and 62 +/- 7%, respectively. Hydrodynamic simulations confirmed the experimental sorting efficiency and a cell damage risk similar to that of normal FACS

    Dimension-independent Harnack inequalities for subordinated semigroups

    Full text link
    Dimension-independent Harnack inequalities are derived for a class of subordinate semigroups. In particular, for a diffusion satisfying the Bakry-Emery curvature condition, the subordinate semigroup with power α\alpha satisfies a dimension-free Harnack inequality provided α(1/2,1)\alpha \in(1/2, 1), and it satisfies the log-Harnack inequality for all α(0,1).\alpha \in (0,1). Some infinite-dimensional examples are also presented

    Geroch--Kinnersley--Chitre group for Dilaton--Axion Gravity

    Get PDF
    Kinnersley--type representation is constructed for the four--dimensional Einstein--Maxwell--dilaton--axion system restricted to space--times possessing two non--null commuting Killing symmetries. New representation essentially uses the matrix--valued SL(2,R)SL(2,R) formulation and effectively reduces the construction of the Geroch group to the corresponding problem for the vacuum Einstein equations. An infinite hierarchy of potentials is introduced in terms of 2×22\times 2 real symmetric matrices generalizing the scalar hierarchy of Kinnersley--Chitre known for the vacuum Einstein equations.Comment: Published in ``Quantum Field Theory under the Influence of External Conditions'', M. Bordag (Ed.) (Proc. of the International Workshop, Leipzig, Germany, 18--22 September 1995), B.G. Teubner Verlagsgessellschaft, Stuttgart--Leipzig, 1996, pp. 228-23

    SUSY parameter determination at the LHC using cross sections and kinematic edges

    Full text link
    We study the determination of supersymmetric parameters at the LHC from a global fit including cross sections and edges of kinematic distributions. For illustration, we focus on a minimal supergravity scenario and discuss how well it can be constrained at the LHC operating at 7 and 14 TeV collision energy, respectively. We find that the inclusion of cross sections greatly improves the accuracy of the SUSY parameter determination, and allows to reliably extract model parameters even in the initial phase of LHC data taking with 7 TeV collision energy and 1/fb integrated luminosity. Moreover, cross section information may be essential to study more general scenarios, such as those with non-universal gaugino masses, and distinguish them from minimal, universal, models.Comment: 22 pages, 8 figure

    Statistical Analysis of the Road Network of India

    Full text link
    In this paper we study the Indian Highway Network as a complex network where the junction points are considered as nodes, and the links are formed by an existing connection. We explore the topological properties and community structure of the network. We observe that the Indian Highway Network displays small world properties and is assortative in nature. We also identify the most important road-junctions (or cities) in the highway network based on the betweenness centrality of the node. This could help in identifying the potential congestion points in the network. Our study is of practical importance and could provide a novel approach to reduce congestion and improve the performance of the highway networ

    Home country advantage? The influence of Italian, German and Austrian employee representatives in the UniCredit European Works Council

    Get PDF
    This article examines the first European Works Council (EWC) to be established in the Italian banking sector, at UniCredit. It focuses on the interaction between Italian, German and Austrian delegations of employee representatives and on the perspectives and practices that reflect their different cultural and institutional backgrounds in industrial relations. Much of the literature suggests that employee representatives from the home country of a multinational company are likely to mould EWC structures in accordance with their own national backgrounds and have greater confidence in dealing with central management in EWC meetings. Our findings partly substantiate this argument, but also suggest that minority delegations, when they have the benefit of strong national institutional arrangements and less fragmented union patterns, are more likely to be cohesive and experienced and therefore able to challenge management and sometimes win significant arguments over strategy

    To dash or to dawdle: verb-associated speed of motion influences eye movements during spoken sentence comprehension

    Get PDF
    In describing motion events verbs of manner provide information about the speed of agents or objects in those events. We used eye tracking to investigate how inferences about this verb-associated speed of motion would influence the time course of attention to a visual scene that matched an event described in language. Eye movements were recorded as participants heard spoken sentences with verbs that implied a fast (“dash”) or slow (“dawdle”) movement of an agent towards a goal. These sentences were heard whilst participants concurrently looked at scenes depicting the agent and a path which led to the goal object. Our results indicate a mapping of events onto the visual scene consistent with participants mentally simulating the movement of the agent along the path towards the goal: when the verb implies a slow manner of motion, participants look more often and longer along the path to the goal; when the verb implies a fast manner of motion, participants tend to look earlier at the goal and less on the path. These results reveal that event comprehension in the presence of a visual world involves establishing and dynamically updating the locations of entities in response to linguistic descriptions of events
    corecore