Sample records for fixed point action

  1. Characteristic Fixed-Point Sets of Semifree Actions on Spheres

    E-print Network

    Davis, James F.

    be- lieved [25]. In [31] the general PL, locally linear, fixed-point set theory is reducedCharacteristic Fixed-Point Sets of Semifree Actions on Spheres JAMES F. DAVIS Indiana University fixed-point set. P. A. Smith showed that when a finite group of order q acts semifreely on a sphere

  2. Fixed-Point Actions in 1-Loop Perturbation Theory

    E-print Network

    Peter Hasenfratz; Ferenc Niedermayer

    1997-06-02

    It has been pointed out in recent papers that the example considered earlier in the O(N) sigma-model to test whether fixed-point actions are 1-loop perfect actually checked classical perfection only. To clarify the issue we constructed the renormalized trajectory explicitly in 1-loop perturbation theory. We found that the fixed-point action is not exactly 1-loop perfect. The cut-off effects are, however, strongly reduced also on the 1-loop level relative to those of the standard and tree level improved Symanzik actions. Some points on off- and on-shell improvement, Symanzik's program and fixed-point actions are also discussed.

  3. New fixed point action for SU(3) lattice gauge theory

    E-print Network

    Marc Blatter; Ferenc Niedermayer

    1996-05-14

    We present a new fixed point action for SU(3) lattice gauge theory, which has --- compared to earlier published fixed point actions --- shorter interaction range and smaller violations of rotational symmetry in the static $q\\bar{q}$-potential even at shortest distances.

  4. Instantons and Fixed Point Actions in SU(2) Gauge Theory

    E-print Network

    Thomas DeGrand; Anna Hasenfratz; Decai Zhu

    1996-03-20

    We describe the properties of instantons in lattice gauge theory when the action is a fixed point action of some renormalization group transformation. We present a theoretically consistent method for measuring topological charge using an inverse renormalization group transformation. We show that, using a fixed point action, the action of smooth configurations with non-zero topological charge is greater than or equal to its continuum value $8\\pi^2/g^2$.

  5. Fixed point actions for SU(3) gauge theory

    E-print Network

    T. DeGrand; A. Hasenfratz; P. Hasenfratz; F. Niedermayer

    1995-08-23

    We summarize our recent work on the construction and properties of fixed point (FP) actions for lattice $SU(3)$ pure gauge theory. These actions have scale invariant instanton solutions and their spectrum is exact through 1--loop, i.e. in their physical predictions there are no $a^n$ nor $g^2 a^n$ cut--off effects for any $n$. We present a few-parameter approximation to a classical FP action which is valid for short correlation lengths. We perform a scaling test of the action by computing the quantity $G = L \\sqrt{\\sigma(L)}$, where the string tension $\\sigma(L)$ is measured from the torelon mass $\\mu = L \\sigma(L)$, on lattices of fixed physical volume and varying lattice spacing $a$. While the Wilson action shows scaling violations of about ten per cent, the approximate fixed point action scales within the statistical errors for $ 1/2 \\ge aT_c$.

  6. Fixed point actions in SU(3) gauge theory: surface tension and topology

    E-print Network

    F. Farchioni; A. Papa

    1997-10-04

    This work is organized in two independent parts. In the first part are presented some results concerning the surface tension in SU(3) obtained with a parametrized fixed point action. In the second part, a new, approximately scale-invariant, parametrized fixed point action is proposed which is suitable to study the topology in SU(3).

  7. The classically perfect fixed point action for SU(3) gauge theory

    E-print Network

    T. DeGrand; A. Hasenfratz; P. Hasenfratz; F. Niedermayer

    1995-06-27

    In this paper (the first of a series) we describe the construction of fixed point actions for lattice $SU(3)$ pure gauge theory. Fixed point actions have scale invariant instanton solutions and the spectrum of their quadratic part is exact (they are classical perfect actions). We argue that the fixed point action is even 1--loop quantum perfect, i.e. in its physical predictions there are no $g^2 a^n$ cut--off effects for any $n$. We discuss the construction of fixed point operators and present examples. The lowest order $q {\\bar q}$ potential $V(\\vec{r})$ obtained from the fixed point Polyakov loop correlator is free of any cut--off effects which go to zero as an inverse power of the distance $r$.

  8. Towards a perfect fixed point action for SU(3) gauge theory

    E-print Network

    T. DeGrand; A. Hasenfratz; P. Hasenfratz; F. Niedermayer; U. Weise

    1994-12-12

    We present an overview of the construction and testing of actions for SU(3) gauge theory which are approximate fixed points of renormalization group equations (at $\\beta\\rightarrow \\infty$). Such actions are candidates for use in numerical simulations on coarse lattices.

  9. Scaling and Topological Charge of a Fixed Point Action for $SU(2)$ Gauge Theory

    E-print Network

    Thomas DeGrand; Anna Hasenfratz; Decai Zhu

    1996-04-18

    We construct a few parameter approximate fixed point action for SU(2) pure gauge theory and subject it to scaling tests, via Monte Carlo simulation. We measure the critical coupling for deconfinement for lattices of temporal extent $N_t=2$, 3, 4, the torelon mass at fixed physical volume, and the string tension (and heavy quark potential) from Wilson loops. We calculate the topological susceptibility using inverse blocking and show that it scales over the observed range of lattice spacings.

  10. Non--perturbative tests of the fixed point action for SU(3) gauge theory

    E-print Network

    T. DeGrand; A. Hasenfratz; P. Hasenfratz; F. Niedermayer

    1995-06-27

    In this paper (the second of a series) we extend our calculation of a classical fixed point action for lattice $SU(3)$ pure gauge theory to include gauge configurations with large fluctuations. The action is parameterized in terms of closed loops of link variables. We construct a few-parameter approximation to the classical FP action which is valid for short correlation lengths. We perform a scaling test of the action by computing the quantity $G = L \\sqrt{\\sigma(L)}$ where the string tension $\\sigma(L)$ is measured from the torelon mass $\\mu = L \\sigma(L)$. We measure $G$ on lattices of fixed physical volume and varying lattice spacing $a$ (which we define through the deconfinement temperature). While the Wilson action shows scaling violations of about ten per cent, the approximate fixed point action scales within the statistical errors for $ 1/2 \\ge aT_c \\ge 1/6$. Similar behaviour is found for the potential measured in a fixed physical volume.

  11. Equivariant Fixed Point Theory

    Microsoft Academic Search

    Kate Ponto

    2009-01-01

    The Lefschetz fixed point theorem and its converse have many generalizations. One of these generalizations is to endomorphisms of a space with a group action. In this paper we define equivariant Lefschetz numbers and Reidemeister traces using traces in bicategories with shadows. We use the functoriality of this trace to identify different forms of these invariants and to prove an

  12. Fixed Point Theory

    Microsoft Academic Search

    Zoltán Ésik

    2009-01-01

    Fixed points and fixed point computations occur in just about every field of Computer Science. It has been noticed that several\\u000a fundamental theorems are consequences of just a few equational properties of fixed point operations. This chapter gives an\\u000a introduction to that part of the theory of fixed points that has applications to weighted automata and languages.

  13. Topology at the Deconfinement Transition Uncovered by Inverse Blocking in SU(2) Pure Gauge Theory with Fixed Point Action

    E-print Network

    M. Feurstein; E. -M. Ilgenfritz; M. Müller-Preussker; S. Thurner

    1997-10-20

    Renormalization group transformations as discussed recently in deriving fixed point actions are used to analyse the vacuum structure near to the deconfinement temperature. Monte Carlo configurations are generated using the fixed point action. We compare equilibrium configurations with configurations obtained by inverse blocking from a coarser lattice. The absence of short range vacuum fluctuations in the latter does not influence the string tension. For the inversely blocked configurations we find the following: (i) the topological susceptibility chi_top is consistent with the phenomenological value in the confinement phase, (ii) chi_top drops across the deconfinement transition, (iii) density and size of instantons are estimated, (iv) the topological density is found to be correlated to Abelian monopole currents and (v) the density of spacelike monopole currents becomes a confinement order parameter.

  14. The absence of cut--off effects for the fixed point action in 1--loop perturbation theory

    E-print Network

    F. Farchioni; P. Hasenfratz; F. Niedermayer; A. Papa

    1995-06-28

    In order to support the formal renormalization group arguments that the fixed point action of an asymptotically free model gives cut--off independent physical predictions in 1--loop perturbation theory, we calculate the finite volume mass--gap $m(L)$ in the non--linear $\\sigma$--model. No cut--off effect of the type $g^4\\left(a/L\\right)^n$ is seen for any $n$. The results are compared with those of the standard and tree level improved Symanzik actions.

  15. Relative fixed point theory

    Microsoft Academic Search

    Kate Ponto

    2009-01-01

    The Lefschetz fixed point theorem and its converse have many generalizations. One of these generalizations is to endomorphisms of a space relative to a fixed subspace. In this paper we define relative Lefschetz numbers and Reidemeister traces using traces in bicategories with shadows. We use the functoriality of this trace to identify different forms of these invariants and to prove

  16. Symplectic invariants of elliptic fixed points

    Microsoft Academic Search

    Karl Friedrich Siburg

    2000-01-01

    To the germ of an area--preserving diffeomorphism at an elliptic fixed point, we associate the germ of Mather's minimal action. This yields a strictly convex function which is symplectically invariant and comprises the classical Birkhoff invariants as the Taylor coefficients of its convex conjugate. In addition, however, the minimal action contains information about the local dynamics near the fixed point;

  17. fixed point sets of finite

    E-print Network

    Ravenel, Douglas

    role in chromatic homotopy theory. #12;Homotopy fixed point sets of finite subgroups of Sn Background role in chromatic homotopy theory. #12;Homotopy fixed point sets of finite subgroups of Sn Background role in chromatic homotopy theory. #12;Homotopy fixed point sets of finite subgroups of Sn Background

  18. Further evidence for a gravitational fixed point

    SciTech Connect

    Percacci, Roberto [SISSA, via Beirut 4, I-34014 Trieste (Italy); INFN, Sezione di Trieste (Italy)

    2006-02-15

    A theory of gravity with a generic action functional and minimally coupled to N matter fields has a nontrivial fixed point in the leading large N approximation. At this fixed point, the cosmological constant and Newton's constant are nonzero and UV relevant; the curvature squared terms are asymptotically free with marginal behavior; all higher order terms are irrelevant and can be set to zero by a suitable choice of cutoff function.

  19. Further Evidence for a Gravitational Fixed Point

    E-print Network

    Percacci, R

    2006-01-01

    A theory of gravity with a generic action functional and minimally coupled to N matter fields has a nontrivial fixed point in the leading large N approximation. At this fixed point, the cosmological constant and Newton's constant are nonzero and UV relevant; the curvature squared terms are asymptotically free with marginal behaviour; all higher order terms are irrelevant and can be set to zero by a suitable choice of cutoff function.

  20. Gravitational Fixed Points from Perturbation Theory

    SciTech Connect

    Niedermaier, Max R. [CNRS, Laboratoire de Mathematiques et Physique Theorique, 37000 Tours (France)

    2009-09-04

    The fixed point structure of the renormalization flow in higher derivative gravity is investigated in terms of the background covariant effective action using an operator cutoff that keeps track of powerlike divergences. Spectral positivity of the gauge fixed Hessian can be satisfied upon expansion in the asymptotically free higher derivative coupling. At one-loop order in this coupling strictly positive fixed points are found for the dimensionless Newton constant g{sub N} and the cosmological constant lambda, which are determined solely by the coefficients of the powerlike divergences. The renormalization flow is asymptotically safe with respect to this fixed point and settles on a lambda(g{sub N}) trajectory after O(10) units of the renormalization mass scale to accuracy 10{sup -7}.

  1. Nielsen Fixed Point Theory Ross Geoghegany

    E-print Network

    Geoghegan, Ross

    Nielsen Fixed Point Theory Ross Nielsen Fixed Point Theory combines the ideas of the Lefschetz Fixed Point T* *heorem the theory is named in his honor. The fixed point set, Fix(f), of a map f : X ! X is {x 2 X|f(x) = x

  2. Epsilon Nielsen fixed point theory

    Microsoft Academic Search

    Robert F. Brown

    2006-01-01

    Let f : X ? X be a map of a compact, connected Riemannian manifold, with or without boundary. For > 0s ufficiently small, we introduce an-Nielsen number N( f )t hat is a lower bound for the number of fixed points of all self-maps of X that are-homotopic to f . We prove that there is always a map

  3. Nielsen Fixed Point Theory Ross Geoghegan y

    E-print Network

    Geoghegan, Ross

    Nielsen Fixed Point Theory Ross Geoghegan y This is a draft chapter for ``Handbook of Geometric Point Theory combines the ideas of the Lefschetz Fixed Point Theorem with the fundamental group in the work of Nielsen [N] and that is why the theory is named in his honor. The fixed point set, Fix

  4. Fixed point theory and trace for bicategories

    Microsoft Academic Search

    Kate Ponto

    2008-01-01

    The Lefschetz fixed point theorem follows easily from the identification of the Lefschetz number with the fixed point index. This identification is a consequence of the functoriality of the trace in symmetric monoidal categories. There are refinements of the Lefschetz number and the fixed point index that give a converse to the Lefschetz fixed point theorem. An important part of

  5. The plane fixed point problem

    Microsoft Academic Search

    Robbert J. Fokkink; John C. Mayer; Lex G. Oversteegen; E. D. Tymchatyn

    2008-01-01

    In this paper we present proofs of basic results, including those developed\\u000aso far by H. Bell, for the plane fixed point problem. Some of these results had\\u000abeen announced much earlier by Bell but without accessible proofs. We define\\u000athe concept of the variation of a map on a simple closed curve and relate it to\\u000athe index of

  6. Fixed point theory for cyclic ? -contractions

    Microsoft Academic Search

    M?d?lina P?curar; Ioan A. Rus

    2010-01-01

    Following [W.A. Kirk, P.S. Srinivasan, P. Veeramany, Fixed points for mappings satisfying cyclical contractive conditions, Fixed Point Theory 4 (1) (2003) 79–89], we present a fixed point theorem for cyclic ?-contractions and following [I.A. Rus, The theory of a metrical fixed point theorem: Theoretical and applicative relevances, Fixed Point Theory 9 (2) (2008) 541–559] we construct a theory of this

  7. Heterogeneous Fixed Points with Application to Points-to Analysis

    E-print Network

    Kanade, Aditya

    be guaranteed using classical fixed point theory. In this paper, we define general conditions to guarantee, we call them heterogeneous fixed points. We illustrate heterogeneous fixed point theory through using heterogeneous fixed point theory. 2 Points-to Analyses In this section, we show that monotonicity

  8. Multiple Fixed-Point Cell

    NASA Astrophysics Data System (ADS)

    Edler, F.; Ederer, P.

    2014-07-01

    The paper describes the construction and investigation of multiple fixed-point cells usable for the calibration of thermocouples at temperatures above 1100 C. These fixed-point cells made of pure graphite are characterized by a simple construction as well as by a flexible application. The cylindrical basic mount is equipped with a central hole for the insertion of a thermocouple, and with eight drill holes containing exchangeable cartridges which surround the central bore axially symmetrically. The cartridges are filled with different metal-carbon (Me-C) eutectics: cobalt-carbon (Co-C), nickel-carbon (Ni-C), palladium-carbon (Pd-C), and rhodium-carbon (Rh-C). The melting temperatures of the different Me-C eutectics of the cartridges were compared to the melting temperatures of commonly used Me-C eutectic fixed-point cells of the Physikalisch-Technische Bundesanstalt by using a Pt/Pd thermocouple (Co-C, Ni-C) and Type B thermocouples (Pd-C, Rh-C). The uncertainties () of the emfs measured at the inflection points of the melting curves are in the order of a few V which correspond to temperature equivalents between 0.3 K and 0.6 K. Furthermore, the difference between the melting temperatures of the Co-C and Ni-C cartridges was found to be 4.2 K by using simultaneously two sets of four cartridges filled with the two materials and placed alternately in the eight outer holes of one basic mount.

  9. Symplectic fixed points and holomorphic spheres

    NASA Astrophysics Data System (ADS)

    Floer, Andreas

    1988-12-01

    LetP be a symplectic manifold whose symplectic form, integrated over the spheres inP, is proportional to its first Chern class. On the loop space ofP, we consider the variational theory of the symplectic action function perturbed by a Hamiltonian term. In particular, we associate to each isolated invariant set of its gradient flow an Abelian group with a cyclic grading. It is shown to have properties similar to the homology of the Conley index in locally compact spaces. As an application, we show that if the fixed point set of an exact diffeomorphism onP is nondegenerate, then it satisfies the Morse inequalities onP. We also discuss fixed point estimates for general exact diffeomorphisms.

  10. Automatic Floating-Point to Fixed-Point Transformations

    E-print Network

    Evans, Brian L.

    Automatic Floating-Point to Fixed-Point Transformations Kyungtae Han, Alex G. Olson, and Brian L processing and communication algorithms are first simulated using floating-point arithmetic and later transformed into fixed-point arithmetic to reduce implementation complexity. For the floating-point to fixed

  11. Fixed Point Theory of Multivalued Weighted Maps

    Microsoft Academic Search

    Jacobo Pejsachowicz; Robert Skiba

    Without doubt the golden age of fixed point theory for multival- ued map occurred in the post-war period. Motivated by the recently born disciplines of mathematical economics and game theory, using tools from the flourishing algebraic topology of that time, several well known fixed point theorems were proved. Most of the research was done in the area of fixed points

  12. FIXED POINT THEORY OF MULTIVALUED WEIGHTED MAPS

    E-print Network

    Ceragioli, Francesca

    FIXED POINT THEORY OF MULTIVALUED WEIGHTED MAPS JACOBO PEJSACHOWICZ AND ROBERT SKIBA 1. Introduction Without doubt the golden age of fixed point theory for multival- ued map occurred in the post classes of maps. The purpose of this paper is to survey the fixed point theory of two very special classes

  13. On fixed points of stratified maps

    Microsoft Academic Search

    Boju Jiang; Xuezhi Zhao; Hao Zheng

    2007-01-01

    .  Nielsen fixed point theory deals with the fixed point sets of self maps on compact polyhedra. In this note, we shall extend\\u000a it to stratified maps, to consider fixed points on (noncompact) strata. The extension was motivated by our recent work on\\u000a the braid forcing problem in which the deleted symmetric products are indispensable. The stratified viewpoint is theoretically\\u000a as

  14. Fixed point theorems and dissipative processes

    NASA Technical Reports Server (NTRS)

    Hale, J. K.; Lopes, O.

    1972-01-01

    The deficiencies of the theories that characterize the maximal compact invariant set of T as asymptotically stable, and that some iterate of T has a fixed point are discussed. It is shown that this fixed point condition is always satisfied for condensing and local dissipative T. Applications are given to a class of neutral functional differential equations.

  15. VIRTUALLY REPELLING FIXED POINTS. XAVIER BUFF

    E-print Network

    Buff, Xavier

    VIRTUALLY REPELLING FIXED POINTS. XAVIER BUFF Abstract. In this article, we study the notion of virtually repelling fixed point. We first give a definition and an interpretation of it. We then prove that most proper holomorphic mappings f : U V with U contained in V have at least one virtually repelling

  16. Two Generic Results in Fixed Point Theory

    Microsoft Academic Search

    Simeon Reich; Alexander J. Zaslavski

    2006-01-01

    Abstract. We give two examples of the generic approach to fixed point theory. The first example is concerned with the asymptotic behavior of infinite products of non- expansive mappings in Banach spaces and the second with the existence and stability of fixed points of continuous mappings,in finite-dimensional Euclidean spaces.

  17. Fixed Point Theory for Almost Convex Functions

    Microsoft Academic Search

    J. Garcia-falset; E. Llorens-fuster; Brailey Sims

    Introduction Traditionally, metric fixed point theory has sought classes of spaces in which a given type of mapping (nonexpansive, assymptotically or generalized nonexpansive, uniformly Lipschitz, etc.) from a nonempty weakly compact convex set into itself always has a fixed point. In some situations the class of space is determined by the application while there is some degree of freedom in

  18. HIGHER FIXED POINTS OF TOPOLOGICAL HOCHSCHILD HOMOLOGY

    E-print Network

    HIGHER FIXED POINTS OF TOPOLOGICAL HOCHSCHILD HOMOLOGY OF THE INTEGERS AT TWO John Rognes Abstract. We inductively determine the mod two homotopy of the fixed point spaces T (Z)C2n for subgroups ([BM1]) computing the completed algebraic K-theory of the p-adic integers when p is an odd prime

  19. HIGHER FIXED POINTS OF TOPOLOGICAL HOCHSCHILD HOMOLOGY

    E-print Network

    HIGHER FIXED POINTS OF TOPOLOGICAL HOCHSCHILD HOMOLOGY OF THE INTEGERS AT TWO John Rognes Abstract. We inductively determine the mod two homotopy of the fixed point spaces T (Z) C 2 n for subgroups ([BM1]) computing the completed algebraic K­theory of the p­adic integers when p is an odd prime

  20. FIXED POINTS OF ZIRCON AUTOMORPHISMS AXEL HULTMAN

    E-print Network

    Hultman, Axel

    FIXED POINTS OF ZIRCON AUTOMORPHISMS AXEL HULTMAN Abstract. A zircon is a poset in which every induced by the fixed points of any automorphism of a zircon is itself a zircon. This provides a natural.2. A poset P is a zircon if for any non-minimal element x P, the subposet induced by the principal order

  1. Introduction To Metric Fixed Point M.A. Khamsi

    E-print Network

    Khamsi, Mohamed Amine

    Introduction To Metric Fixed Point Theory M.A. Khamsi #12;2 International Workshop on Nonlinear Introduction to Metric Fixed Point Theory The fixed point problem (at the basis of the Fixed Point Theory) may Point Theory is divided into three major areas: 1. Topological Fixed Point Theory 2. Metric Fixed Point

  2. FIXED POINT THEORY APPROACH TO DIFFERENTIAL INCLUSIONS

    Microsoft Academic Search

    Lech Górniewicz

    The aim of this chapter is to give a systematic and unified account of topics in fixed point theory methods of differential inclusions which lie on the border line between topology and ordinary differential equations.

  3. Characterizations of fixed points of quantum operations

    SciTech Connect

    Li Yuan [College of Mathematics and Information Science, Shaanxi Normal University, Xi'an, 710062 (China)

    2011-05-15

    Let {phi}{sub A} be a general quantum operation. An operator B is said to be a fixed point of {phi}{sub A}, if {phi}{sub A}(B)=B. In this note, we shall show conditions under which B, a fixed point {phi}{sub A}, implies that B is compatible with the operation element of {phi}{sub A}. In particular, we offer an extension of the generalized Lueders theorem.

  4. Recent results in analytical fixed point theory

    Microsoft Academic Search

    2005-01-01

    We survey recent results in analytical fixed point theory. Firstly, we state resolutions of long-standing problems in infinite dimensional topology—the Schauder conjecture, the compact AR problem, and the Banach problem on the Hilbert cube. Secondly, we list some fixed point theorems on Kakutani maps, generalized upper hemicontinuous maps, Fan–Browder maps, approximable maps, acyclic maps, and admissible or better admissible class

  5. Infrared fixed point in quantum Einstein gravity

    E-print Network

    S. Nagy; J. Krizsan; K. Sailer

    2012-06-28

    We performed the renormalization group analysis of the quantum Einstein gravity in the deep infrared regime for different types of extensions of the model. It is shown that an attractive infrared point exists in the broken symmetric phase of the model. It is also shown that due to the Gaussian fixed point the IR critical exponent $\

  6. The 290 fixed-point sublattices of the Leech lattice

    E-print Network

    Hoehn, Gerald

    2015-01-01

    We determine the orbits of fixed-point sublattices of the Leech lattice with respect to the action of the Conway group Co_0. There are 290 such orbits. Detailed information about these lattices, the corresponding coinvariant lattices, and the stabilizing subgroups, is tabulated in several tables.

  7. The 290 fixed-point sublattices of the Leech lattice

    E-print Network

    Gerald Hoehn; Geoffrey Mason

    2015-06-09

    We determine the orbits of fixed-point sublattices of the Leech lattice with respect to the action of the Conway group Co_0. There are 290 such orbits. Detailed information about these lattices, the corresponding coinvariant lattices, and the stabilizing subgroups, is tabulated in several tables.

  8. Two results in metric fixed point theory

    Microsoft Academic Search

    Daniel Reem; Simeon Reich; Alexander J. Zaslavski

    2007-01-01

    .??We establish two fixed point theorems for certain mappings of contractive type. The first result is concerned with the case where such mappings take a nonempty, closed subset of a complete metric spaceXintoX, and the second with an application of the continuation method to the case where they satisfy the Leray?Schauder boundary condition in Banach spaces.

  9. Some problems in metric fixed point theory

    Microsoft Academic Search

    Kazimierz Goebel; W. A. Kirk

    2008-01-01

    .  Three papers, published coincidentally and independently by Felix Browder, Dietrich Göhde, and W. A. Kirk in 1965, triggered\\u000a a branch of mathematical research now called metric fixed point theory. This is a survey of some of the highlights of that\\u000a theory, with a special emphasis on some of the problems that remain open.

  10. Precise Point Positioning with Partial Ambiguity Fixing

    PubMed Central

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  11. Ultralimits and fixed-point properties, after Gromov

    E-print Network

    Sart, Remi

    Ultralimits and fixed-point properties, after Gromov Yves Stalder Université Blaise Pascal Geneva, August 26, 2008 Yves Stalder (Université Blaise Pascal) Ultralimits and fixed-point properties Geneva is a fixed point iff S(x) = 0. Yves Stalder (Université Blaise Pascal) Ultralimits and fixed-point properties

  12. Some computational aspects of metric fixed point theory

    E-print Network

    Haller-Dintelmann, Robert

    Some computational aspects of metric fixed point theory Ulrich Kohlenbach Department of Mathematics@mathematik.tu-darmstadt.de Key words: Nonexpansive mappings, fixed point theory, Krasnoselski-Mann iteration, computable analysis on the convergence towards a fixed point. 1 Introduction A substantial part of metric fixed point theory studies

  13. Some computational aspects of metric fixed point theory

    E-print Network

    Kohlenbach, Ulrich

    Some computational aspects of metric fixed point theory Ulrich Kohlenbach Department of Mathematics@mathematik.tu­darmstadt.de Key words: Nonexpansive mappings, fixed point theory, Krasnoselski­Mann iteration, computable analysis on the convergence towards a fixed point. 1 Introduction A substantial part of metric fixed point theory studies

  14. 85 years of Nielsen theory: Fixed Points P. Christopher Staecker

    E-print Network

    Staecker, P. Christopher

    85 years of Nielsen theory: Fixed Points P. Christopher Staecker Fairfield University, Fairfield CT Nielsen Theory and Related Topics 2013 Staecker (Fairfield U.) Fixed points 1 / 48 #12;Thanks Staecker Nielsen theory: Bob Brown, The Lefschetz Fixed Point Theorem, 1977. Staecker (Fairfield U.) Fixed points 3

  15. Holographic Superconductor for a Lifshitz fixed point

    E-print Network

    Sang-Jin Sin; Shan-Shan Xu; Yang Zhou

    2011-05-08

    We consider the gravity dual of strongly coupled system at a Lifshitz-fixed point and finite temperature, which was constructed in a recent work arXiv:0909.0263. We construct an Abelian Higgs model in that background and calculate condensation and conductivity using holographic techniques. We find that condensation happens and DC conductivity blows up when temperature turns below a critical value.

  16. Fixed points of higher-derivative gravity.

    PubMed

    Codello, Alessandro; Percacci, Roberto

    2006-12-01

    We recalculate the beta functions of higher-derivative gravity in four dimensions using the one-loop approximation to an exact renormalization group equation. We reproduce the beta functions of the dimensionless couplings that were known in the literature, but we find new terms for the beta functions of Newton's constant and of the cosmological constant. As a result, the theory appears to be asymptotically safe at a non-Gaussian fixed point rather than perturbatively renormalizable and asymptotically free. PMID:17155791

  17. Fixed Points of Higher-Derivative Gravity

    SciTech Connect

    Codello, Alessandro; Percacci, Roberto [Dipartimento di Fisica Teorica, Universita di Trieste, Viale Miramare, I-34014 Trieste (Italy); SISSA, via Beirut 4, I-34014 Trieste, Italy, and INFN, Sezione di Trieste (Italy)

    2006-12-01

    We recalculate the beta functions of higher-derivative gravity in four dimensions using the one-loop approximation to an exact renormalization group equation. We reproduce the beta functions of the dimensionless couplings that were known in the literature, but we find new terms for the beta functions of Newton's constant and of the cosmological constant. As a result, the theory appears to be asymptotically safe at a non-Gaussian fixed point rather than perturbatively renormalizable and asymptotically free.

  18. Fixed point theorems in ultrametric spaces 

    E-print Network

    Fullbright, Steven Edward

    1972-01-01

    Point Theorems in Ultrametric Spaces. (May 1972) Steven E. Fullbright, B. A. , Texas A&M University M. S. , Texas A&M University Directed by: L. F. Guseman, Jr. and Jack Bryant Let (X, d) be an ultrametric space and f a contractive selfmap of X.... It is shown that the existence of fixed points of f is related to simple properties of the metric d. iv ACKNOWLEDGEMENTS I wish to thank the following people for their assistance and support in writing this thesis: Larry Guseman, who provided guidance...

  19. Non-Trivial Fixed Points of the Scalar Field Theory

    E-print Network

    K. Sailer; W. Greiner

    1996-10-18

    The phase structure of the scalar field theory with arbitrary powers of the gradient operator and a local non-analytic potential is investigated by the help of the RG in Euclidean space. The RG equation for the generating function of the derivative part of the action is derived. Infinitely many non-trivial fixed points of the RG transformations are found. The corresponding effective actions are unbounded from below and do probably not exhibit any particle content. Therefore they do not provide physically sensible theories.

  20. COMPLEX DYNAMICS, GEOMETRIC FUNCTION THEORY, AND A FIXED POINT THEOREM

    E-print Network

    Matache, Dora

    COMPLEX DYNAMICS, GEOMETRIC FUNCTION THEORY, AND A FIXED POINT THEOREM TENG LI Abstract. A fixed, 2013. Key words and phrases. Fixed point theory, Denjoy­Wolff theorem. 1 #12;2 TENG LI Also, (3) | (0­contractive" as a consequence of the existence of a fixed point and their analyticity (which is essen- tial, since the proof

  1. Fixed Point Four-Fermi Theories

    E-print Network

    Simon Hands

    1997-06-24

    I review dynamical chiral symmetry breaking in four-fermi models, including results of Monte Carlo simulations with dynamical fermions. For 2fixed point of the renormalisation group, the continuum theory may either be describable using the large-N_f expansion, as in the case of the Gross-Neveu model, or be intrinsically non-perturbative, as in the case of the Thirring model. For d=4, the models are trivial and are described by a mean field equation of state with logarithmic corrections to scaling, which may nonetheless define new universality classes distinct from those of ferromagnetism.

  2. On Fixed Points of Lüders Operation

    E-print Network

    Liu Weihua; Wu Junde

    2009-09-08

    In this paper, we prove that if $\\mathcal{A}=\\{E_i\\}_{i=1}^{n}$ is a finite commutative quantum measurement, then the fixed points set of L\\"{u}ders operation $L_{{\\cal A}}$ is the commutant ${\\cal A}'$ of ${\\cal A}$, the result answers an open problem partially. We also give a concrete example of a L\\"{u}ders operation $L_{{\\cal A}}$ with $n=3$ such that $L_{{\\cal A}}(B)=B$ does not imply that the quantum effect $B$ commutes with all $E_1, E_2$ and $E_3$, this example answers another open problem.

  3. An intensional fixed point theory over first order arithmetic

    E-print Network

    Jäger, Gerhard

    An intensional fixed point theory over first order arithmetic Gerhard J¨ager Abstract The purpose of this article is to present a new theory IPA() for fixed points over arithmetic which allows the building up points over state spaces in the propositional modal µ-calculus. 1 Introduction Fixed point theories play

  4. Galois Connections and Fixed Point Calculus Roland Backhouse

    E-print Network

    de Gispert, Adrià

    Galois Connections and Fixed Point Calculus Roland Backhouse October 15, 2001 Abstract Fixed point ordered set. This tutorial presents the ba- sic theory of xed point calculus together with a number;2 Contents 1 Introduction 4 1.1 Fixed Point Equations

  5. FIXED POINT METHODS IN NONLINEAR ANALYSIS ZACHARY SMITH

    E-print Network

    May, J. Peter

    . Contents 1. Introduction 1 2. Differential Calculus on Banach Spaces 2 2.1. Banach Fixed Point Theory 2 2 Point Theory 7 3.1. Brouwer Fixed Point Theory 7 3.2. Ascoli-Arzel`a Theory 8 3.3. Schauder Fixed Point Spaces 2.1. Banach Fixed Point Theory. Definition 2.1. Let (X, d) be a metric space and T : M X X

  6. A Combinatorial Proof of a Fixed Point Kenneth Baclawski

    E-print Network

    Baclawski, Kenneth B.

    non- constructive results in the fixed point theory of finite partially ordered sets. Key words: fixedA Combinatorial Proof of a Fixed Point Property Kenneth Baclawski College of Computer is a combinatorial proof of the fixed simplex property for finite pseudo cones in which a combinatorial structure

  7. Fixed point theory for compact absorbing contractive admissible type maps

    Microsoft Academic Search

    Ravi P. Agarwal; Donal ORegan

    2008-01-01

    In this article we present new Lefschetz fixed point theorems for compact absorbing contractive admissible maps between Fréchet spaces. Also, we discuss condensing maps with a compact attractor. Finally we present new antipodal fixed point theory for Kakutani maps.

  8. RANDOM FIXED POINT THEORY FOR MULTIVALUED COUNTABLY CONDENSING RANDOM OPERATORS

    Microsoft Academic Search

    Ravi P. Agarwal; Donal ORegan; M. Sambandham

    2002-01-01

    A variety of random fixed point results are presented for continuous, countably condensing multivalued maps. Our arguments rely on a new result for hemicompact maps and on a new deterministic fixed point result of Agarwal and O'Regan.

  9. Fixed point theory in Fréchet spaces for Volterra type operators

    Microsoft Academic Search

    Donal ORegan; Xu Xian

    2007-01-01

    New fixed point theorems for maps (single and multivalued) between Fréchet spaces are presented. The proof relies on fixed point theory in Banach spaces and viewing a Fréchet space as the projective limit of a sequence of Banach spaces.

  10. Applications of Michael's selection theorems to fixed point theory

    Microsoft Academic Search

    2008-01-01

    Applying some of Ernest Michael's selection theorems, from recent fixed point theorems on u.s.c. multimaps, we deduce generalizations of the classical Bolzano theorem, several fixed point theorems on multimaps defined on almost convex sets, almost fixed point theorems, coincidence theorems, and collectively fixed point theorems. These results are related mainly to Michael maps, that is, l.s.c. multimaps having nonempty closed

  11. Fixed point theorems in ultrametric spaces

    E-print Network

    Fullbright, Steven Edward

    1972-01-01

    that Q * is not compact. P ~Exam le 1. 3. Let T be any nonempty set, and define g(T) to be the set of all sequences of elements of T. A metric d on g(T) can be defined as follows: For x = (x ) y = (y ) in Q(T) x T y, n n k(x, y) min (n c N: x $ y... fixed point of f . Otherwise, let 0 & $ & k & n and note that f (x) $ f (x) . Indeed, if f (x) = f (x), then k k x = fn(x) - fn-k(fk(x)) fn-k(fj(x)) = fn-k+3(x) which contradicts the minimality of n. Thus we have d(f(x), x) & d(f (x), f(x)) ?. . . d...

  12. FIXED-POINT-FREE REPRESENTATIONS OVER FIELDS OF PRIME CHARACTERISTIC

    E-print Network

    FIXED-POINT-FREE REPRESENTATIONS OVER FIELDS OF PRIME CHARACTERISTIC PETER MAYR Abstract as groups of fixed-point-free automorphisms on finite groups are determined. 1. Introduction A group of automorphisms is said to act fixed-point-free on a finite group G iff || > 1 and no automorphism in except

  13. On Fixed point and Looping Combinators in Type Theory

    E-print Network

    Geuvers, Herman

    On Fixed point and Looping Combinators in Type Theory Herman Geuvers and Joep Verkoelen Institute with f(Ln+1f). It was unclear whether a fixed point combinator exists in these systems. Later, Hurkens that arises from it: it is a real looping combinator (not a fixed point combinator) but in the Curry version

  14. Categorical Fixed Point Calculus Roland Backhouse, Marcel Bijsterveld,

    E-print Network

    Backhouse, Roland

    we develop a number of ``fixed­point rules'' in category theory each of which is inspired by (and generalises) a fixed­point rule in lattice theory. We then apply these rules to the construction of a numberCategorical Fixed Point Calculus Roland Backhouse, Marcel Bijsterveld, Rik van Geldrop and Jaap van

  15. Complete Axioms for Categorical Fixed-point Operators Alex Simpson

    E-print Network

    Plotkin, Gordon

    - sarily an iteration operator. 1. Introduction Fixed points play a central r^ole in domain theory. Tra by a form of Gaussian elim- ination, see e.g. [33]. More generally, the equational theory between fixed-point, as exemplified by the many completeness results for the free iteration theory in [3]. As in the case of the fixed-point

  16. Brief Announcement: Consistent Fixed Points and Negative Gain

    E-print Network

    Gouda, Mohamed G.

    state, the network is guaranteed to reach a fixed point [1]. The theory of network stabilization, thoughBrief Announcement: Consistent Fixed Points and Negative Gain Hrishikesh B. Acharya1 , Ehab S.e. starting from any global state, network N is guaranteed to reach a global fixed point. The first principle

  17. Intuitionistic Fixed Point Theories for Strictly Positive Operators

    Microsoft Academic Search

    Christian Rüede; Thomas Strahm

    2002-01-01

    In this paper it is shown that the intuitionistic fixed point theory#IDi# (strict) for # times iterated fixed points of strictly positive operatorforms is conservative for negative arithmetic and #02 sentences over thetheory ACA -i # for # times iterated arithmetic comprehension withoutset parameters. This generalizes results previously due to Buchholz[5] and Arai [2].Keywords: Intuitionistic fixed point theories, strictly positive

  18. The prooftheoretic analysis of transfinitely iterated fixed point theories

    E-print Network

    Jäger, Gerhard

    The proof­theoretic analysis of transfinitely iterated fixed point theories Gerhard J¨ager Reinhard of the transfinitely iterated fixed point theories c ID ff and c ID !ff . 1 Introduction The transfinitely iterated fixed point theories c ID ff are relatives of the better known theories ID ff for iterated inductive

  19. REMARKS ON CARISTI'S FIXED POINT THEOREM M. A. KHAMSI

    E-print Network

    Khamsi, Mohamed Amine

    ] of geometric fixed point theory in Banach spaces. Recall that inwardness conditions are the ones which assertREMARKS ON CARISTI'S FIXED POINT THEOREM M. A. KHAMSI Abstract. In this work, we give a characterization of the existence of min- imal elements in partially ordered sets in terms of fixed point

  20. THE LEFSCHETZ PRINCIPLE, FIXED POINT THEORY, AND INDEX THEORY

    E-print Network

    Heitsch, James L.

    THE LEFSCHETZ PRINCIPLE, FIXED POINT THEORY, AND INDEX THEORY November 5, 2009 JAMES L. HEITSCH Abstract. This is a rough historical account of some uses of the Lefschetz Principle in fixed point theory then follows easily. The Lefschetz Principle extends readily to index theory and general fixed point theory

  1. Collider Signals of Gravitational Fixed Points

    E-print Network

    JoAnne Hewett; Thomas Rizzo

    2007-07-21

    Recent studies have shown that the poor perturbative behavior of General Relativity in the ultraviolet regime may be ameliorated by the existence of a non-Gaussian fixed point which renders the theory asymptotically safe and possibly non-perturbatively renormalizable. This results in a running of the (effective) gravitational coupling such that gravity becomes weaker at high energies. We parameterize this effective coupling with a form factor and study its consequences at the LHC and ILC in models with large extra dimensions or warped extra dimensions. We find significant effects in the processes of Kaluza-Klein (KK) graviton exchange or resonant KK graviton production in both the Drell-Yan reaction as well as in $e^+e^-\\to f\\bar f$. On the otherhand, processes leading to KK graviton emission show qualitatively less sensitivity to the presence of a form factor. In addition, we examine tree-level perturbative unitarity in $2\\to 2$ gravity-mediated scattering and find that this form factor produces a far better behaved amplitude at large center of mass energies.

  2. DRAFT --DRAFT --DRAFT --DRAFT --DRAFT --Fixed Points Theorems

    E-print Network

    Liverani, Carlangelo

    DRAFT DRAFT -- DRAFT -- DRAFT -- DRAFT -- DRAFT -- Appendix A Fixed Points Theorems (an of the previous chapters. A.1 Banach Fixed Point Theorem Theorem A.1.1 (Fixed point contraction) Given a BanachL. This means that, for each n, m N, an, a0 A and am, an+m Am, hence an+m - am mL. That is 205 #12;DRAFT

  3. Asymptotic fixed point theory and the beer barrel theorem

    Microsoft Academic Search

    John Mallet-Paret; Roger D. Nussbaum

    2008-01-01

    .  In Sections 2 and 3 of this paper we refine and generalize theorems of Nussbaum (see [42]) concerning the approximate fixed\\u000a point index and the fixed point index class. In Section 4 we indicate how these results imply a wide variety of asymptotic\\u000a fixed point theorems. In Section 5 we prove a generalization of the mod p theorem: if p

  4. Stability in functional differential equations established using fixed point theory

    Microsoft Academic Search

    Chuhua Jin; Jiaowan Luo

    2008-01-01

    In this paper we consider a nonlinear scalar delay differential equation with variable delays and give some new conditions for the boundedness and stability by means of Krasnoselskii’s fixed point theory. A stability theorem with a necessary and sufficient condition is proved. The results in [T.A. Burton, Stability by fixed point theory or Liapunov’s theory: A comparison, Fixed Point Theory

  5. Some new results and generalizations in metric fixed point theory

    Microsoft Academic Search

    Wei-Shih Du

    2010-01-01

    The main purpose of this paper is the study of the generalization of some results given in [M. Berinde, V. Berinde, On a general class of multi-valued weakly Picard mappings, J. Math. Anal. Appl. 326 (2007) 772–782] and references therein. Some generalizations of the Mizoguchi–Takahashi fixed point theorem, Kannan’s fixed point theorems and Chatterjea’s fixed point theorems are established by

  6. PURE STRATEGY NASH EQUILIBRIUM POINTS AND THE LEFSCHETZ FIXED POINT THEOREM

    E-print Network

    Tesfatsion, Leigh

    to have appeared in either the economic or game theory literature. The Lefschetz approach to fixed pointPURE STRATEGY NASH EQUILIBRIUM POINTS AND THE LEFSCHETZ FIXED POINT THEOREM by Leigh Tesfatsion spaces. The principal tool used in the proof is a Lefschetz fixed point theorem for multivalued maps

  7. Gauge and Cutoff Function Dependence of the Ultraviolet Fixed Point in Quantum Gravity

    E-print Network

    Wataru Souma

    2000-06-03

    The exact renormalization group equation for pure quantum gravity is derived for an arbitrary gauge parameter in the space-time dimension $d=4$. This equation is given by a non-linear functional differential equation for the effective average action. An action functional of the effective average action is approximated by the same functional space of the Einstein-Hilbert action. From this approximation, $\\beta$-functions for the dimensionless Newton constant and cosmological constant are derived non-perturbatively. These are used for an analysis of the phase structure and the ultraviolet non-Gaussian fixed point of the dimensionless Newton constant. This fixed point strongly depends on the gauge parameter and the cutoff function. However, this fixed point exists without these ambiguities, except for some gauges. Hence, it is possible that pure quantum gravity in $d=4$ is an asymptotically safe theory and non-perturbatively renormalizable.

  8. A fixed-point fast Fourier transform error analysis

    Microsoft Academic Search

    PETER D. WELCH

    1969-01-01

    This paper contains an analysis of the fixed-point accuracy of the power of two, fast Fourier transform algorithm. This analysis leads to approximate upper and lower bounds on the root-mean-square error. Also included are the results of some accuracy experiments on a simulated fixed-point machine and their comparison with the error upper bound.

  9. An analog scheme for fixed point computation. I. Theory

    Microsoft Academic Search

    V. S. Borkar; K. Soumyanatha

    1997-01-01

    An analog system for fixed point computation is described. The system is derived from a continuous time analog of the classical over-relaxed fixed point iteration. The dynamical system is proved to converge for nonexpansive mappings under all p norms, p?(1,?). This extends previously established results to not necessarily differentiable maps which are nonexpansive under the ?-norm. The system will always

  10. Fixed Point Theory for Self Maps between Fréchet Spaces

    Microsoft Academic Search

    Ravi P. Agarwal; Donal O'Regan

    2001-01-01

    Using Krasnoselskii's fixed point theorem in a cone, we present a new fixed point theory for multivalued self maps between Fréchet spaces. Our analysis relies on a diagonal process and a result on hemicompact maps due to K. K. Tan and X. Z. Yuan (1994, J. Math. Anal. Appl.185, 378–390). An application is given to illustrate the theory.

  11. Some recent results in metric fixed point theory

    Microsoft Academic Search

    W. A. Kirk

    2007-01-01

    .  This is a survey of recent results on best approximation and fixed point theory in certain geodesic spaces. Some of these\\u000a results are related to fundamental fixed point theorems in topology that have been known for many years. However the metric\\u000a approach is emphasized here.

  12. LOCAL FIXED POINT THEORY INVOLVING THREE OPERATORS IN BANACH ALGEBRAS

    Microsoft Academic Search

    B. C. Dhage

    The present paper studies the local versions of a fixed point theorem of Dhage (1987) in Banach algebras. An application of the newly developed fixed point theorem is also discussed for proving the existence results to a nonlinear functional integral equation of mixed type.

  13. An intensional fixed point theory over first order arithmetic

    Microsoft Academic Search

    Gerhard Jäger

    2004-01-01

    The purpose of this article is to present a new theory IPA( ) for fixed points over arithmetic which allows the building up of fixed points in a very nested and entangled way. But in spite of its great expressive power we can show that the proof-theoretic strength of our theory - which is intensional in a meaning to be

  14. The Fixed Point Theory of Unbounded NonDeterminism

    Microsoft Academic Search

    Geoff Barrett

    1991-01-01

    This paper presents a fixed point theorem for the infinite traces model of CSP. Unlike any other model of CSP, there is no complete partial order over the infinite traces model whose fixed point theory agrees with the operational semantics (A. W. Roscoe, Oxford University Computing Laboratory Technical Monograph PRG-67, 1988). This arises from the introduction of unbounded non-determinism. However,

  15. Identification of Wiener systems based on fixed point theory

    Microsoft Academic Search

    Guoqi Li; Changyun Wen

    2010-01-01

    In this paper, we propose a new method for the identification of Wiener systems based on fixed point theory. The linear part of the system is an infinite impulse response (IIR) system and the nonlinear static function is allowed to be non-continuous or non-smooth. Our proposed technique transforms the estimation of parameters to finding a fixed point of a nonlinear

  16. Fixed points and infrared completion of quantum gravity

    E-print Network

    Nicolai Christiansen; Daniel F. Litim; Jan M. Pawlowski; Andreas Rodigast

    2012-09-18

    The phase diagram of four-dimensional Einstein-Hilbert gravity is studied using Wilson's renormalization group. Smooth trajectories connecting the ultraviolet fixed point at short distances with attractive infrared fixed points at long distances are derived from the non-perturbative graviton propagator. Implications for the asymptotic safety conjecture and further results are discussed.

  17. Neural Networks and Minimal Fixed Point Semantics for Logic Programs

    E-print Network

    Seda, Anthony Karel

    Neural Networks and Minimal Fixed Point Semantics for Logic Programs Vladimir Komendantsky School networks of the well-known immediate consequence operator TP determined by a normal logic program P semantics for P. Keywords: logic programs, fibring neural networks, least fixed point semantics. 1

  18. KAM-tori near an analytic elliptic fixed point

    NASA Astrophysics Data System (ADS)

    Eliasson, L. Hakan; Fayad, Bassam; Krikorian, Raphaël

    2013-11-01

    We study the accumulation of an elliptic fixed point of a real analytic Hamiltonian by quasi-periodic invariant tori. We show that a fixed point with Diophantine frequency vector ? 0 is always accumulated by invariant complex analytic KAM-tori. Indeed, the following alternative holds: If the Birkhoff normal form of the Hamiltonian at the invariant point satisfies a Rüssmann transversality condition, the fixed point is accumulated by real analytic KAM-tori which cover positive Lebesgue measure in the phase space (in this part it suffices to assume that ? 0 has rationally independent coordinates). If the Birkhoff normal form is degenerate, there exists an analytic subvariety of complex dimension at least d + 1 passing through 0 that is foliated by complex analytic KAM-tori with frequency ? 0. This is an extension of previous results obtained in [1] to the case of an elliptic fixed point.

  19. Coincidence and fixed points in symmetric spaces under strict contractions

    NASA Astrophysics Data System (ADS)

    Imdad, M.; Ali, Javid; Khan, Ladlay

    2006-08-01

    Some common fixed point theorems due to Aamri and El Moutawakil [M. Aamri, D. El Moutawakil, Some new common fixed point theorems under strict contractive conditions, J. Math. Anal. Appl. 270 (2002) 181-188] and Pant and Pant [R.P. Pant, V. Pant, Common fixed points under strict contractive conditions, J. Math. Anal. Appl. 248 (2000) 327-332] proved for strict contractive mappings in metric spaces are extended to symmetric (semi-metric) spaces under tight conditions. Some related results are derived besides discussing illustrative examples which establish the utility of results proved in this note.

  20. Fixed point and coincidence theory on circle bouquets in ten minutes

    E-print Network

    Staecker, P. Christopher

    Fixed point and coincidence theory on circle bouquets in ten minutes Chris Staecker MEB school meeting, March 25 2009 Staecker () Circle bouquets MEB 1 / 18 #12;Fixed Points A fixed point is some point;Fixed Points A fixed point is some point x with f (x) = x. We can find them on a graph like so: Staecker

  1. A further generalization of the Kakutani fixed point theorem with application to Nash equilibrium points

    Microsoft Academic Search

    I. L. Glicksberg

    Introduction. Kakutani's fixed point theorem (3)1 states that in Euclidean «-space a closed point to (nonvoid) convex set map of a convex compact set into itself has a fixed point. Kakutani showed that this implied the minimax theorem for finite games. The object of this note is to point out that Kakutani's theorem may be extended to convex linear topological

  2. 52. Fixed Span, Top Chord at Panel Point 6; diagonal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. Fixed Span, Top Chord at Panel Point 6; diagonal member goes to intermediate connection 7 & then to bottom chord at 8; looking ESE. - Pacific Shortline Bridge, U.S. Route 20,spanning Missouri River, Sioux City, Woodbury County, IA

  3. On Fixed Points of Order K of RSA

    E-print Network

    Zhang, Shaohua

    2009-01-01

    In this paper, we gave a preliminary dynamical analysis on the RSA cryptosystem and obtained a computational formulae of the number of the fixed points of $k$ order of the RSA. Thus, the problem in [8, 9] has been solved.

  4. The Fixed Point Theory for Some Generalized Nonexpansive Mappings

    Microsoft Academic Search

    Enrique Llorens Fuster; Elena Moreno Gálvez

    2011-01-01

    We study some aspects of the fixed point theory for a class of generalized\\u000anonexpansive mappings, which among others contain the class of generalized\\u000anonexpansive mappings recently defined by Suzuki in 2008.

  5. General equilibrium and fixed point theory: A partial survey

    Microsoft Academic Search

    Hichem Ben-El-Mechaiekh; Philippe Bich; Monique Florenzano

    2009-01-01

    .  Focusing mainly on equilibrium existence results, this paper emphasizes the role of fixed point theorems in the development\\u000a of general equilibrium theory, for its standard definition as well as for some of its extensions.

  6. Supersymmetric Quantum Mechanics and Lefschetz fixed-point formula

    E-print Network

    Si Li

    2005-11-09

    We review the explicit derivation of the Gauss-Bonet and Hirzebruch formulae by physical model and give a physical proof of the Lefschetz fixed-point formula by twisting boundary conditions for the path integral.

  7. Fixed Point Theory And The K-Theoretic Trace

    Microsoft Academic Search

    Ross Geoghegan; Andrew Nicas

    1996-01-01

    . The relationship between fixed point theory and K --theory is explained, bothclassical Nielsen theory (versus K0 ) and 1--parameter fixed point theory (versus K1 ). Inparticular, various zeta functions associated with suspension flows are shown to come in anatural way as "traces" of "torsions" of Whitehead and Reidemeister type.x1. IntroductionConsider the following facts:1. In modern geometric topology, K --theoretic

  8. Fixed point theory of multimaps in abstract convex uniform spaces

    Microsoft Academic Search

    2009-01-01

    This is to establish fixed point theorems for multimaps in abstract convex uniform spaces. Our new results generalize corresponding ones in topological vector spaces (t.v.s.), convex spaces due to Lassonde, C-spaces due to Horvath, and G-convex spaces due to Park. We show that fixed point theorems on multimaps of the Fan–Browder type, multimaps having ranges of the Zima–Hadži? type, and

  9. Equivariant Nielsen fixed point theory for n-valued maps

    Microsoft Academic Search

    Joel Better

    2010-01-01

    We develop an equivariant Nielsen fixed point theory for n-valued G-maps by associating (as in Better (2010) [2]) an abstract simplicial complex to any equivariant n-valued map and defining, in terms of this complex, two n-valued continuous G-homotopy invariants that are lower bounds for the number of fixed points and of orbits in the n-valued continuous G-homotopy class of a

  10. Non-Trivial Ultraviolet Fixed Point in Quantum Gravity

    E-print Network

    Wataru Souma

    1999-07-06

    The non-trivial ultraviolet fixed point in quantum gravity is calculated by means of the exact renormalization group equation in d-dimensions $(2\\simeq d\\leq4)$. It is shown that the ultraviolet non-Gaussian fixed point which is expected from the perturbatively $\\epsilon$-expanded calculations in $2+\\epsilon$ gravity theory remains in d=4. Hence it is possible that quantum gravity is an asymptotically safe theory and renormalizable in 2

  11. Image integrity authentication scheme based on fixed point theory.

    PubMed

    Li, Xu; Sun, Xingming; Liu, Quansheng

    2015-02-01

    Based on the fixed point theory, this paper proposes a new scheme for image integrity authentication, which is very different from digital signature and fragile watermarking. By the new scheme, the sender transforms an original image into a fixed point image (very close to the original one) of a well-chosen transform and sends the fixed point image (instead of the original one) to the receiver; using the same transform, the receiver checks the integrity of the received image by testing whether it is a fixed point image and locates the tampered areas if the image has been modified during the transmission. A realization of the new scheme is based on Gaussian convolution and deconvolution (GCD) transform, for which an existence theorem of fixed points is proved. The semifragility is analyzed via commutativity of transforms, and three commutativity theorems are found for the GCD transform. Three iterative algorithms are presented for finding a fixed point image with a few numbers of iterations, and for the whole procedure of image integrity authentication; a fragile authentication system and a semifragile one are separately built. Experiments show that both the systems have good performance in transparence, fragility, security, and tampering localization. In particular, the semifragile system can perfectly resist the rotation by a multiple of 90° flipping and brightness attacks. PMID:25420259

  12. On a fixed point in the metric space of normalized Hausdorff moment sequences

    E-print Network

    Berg, Christian

    classical results on attracting fixed points. For classical fixed point theory see [5]. The purposeOn a fixed point in the metric space of normalized Hausdorff moment sequences Christian Berg fixed point, which is attractive. The fixed point turns out to be a Hausdorff moment sequence studied

  13. Positive area and inaccessible fixed points for hedgehogs

    E-print Network

    Biswas, Kingshook

    2010-01-01

    Let f be a germ of holomorphic diffeomorphism with an irra- tionally indifferent fixed point at the origin in C (i.e. f(0) = 0, f'(0) = e 2pi i alpha, alpha in R - Q). Perez-Marco showed the existence of a unique family of nontrivial invariant full continua containing the fixed point called Siegel compacta. When f is non-linearizable (i.e. not holomorphically conjugate to the rigid rotation R_{alpha}(z) = e 2pi i z) the invariant compacts obtained are called hedgehogs. Perez-Marco developed techniques for the construction of examples of non-linearizable germs; these were used by the author to construct hedge- hogs of Hausdorff dimension one, and adapted by Cheritat to construct Siegel disks with pseudo-circle boundaries. We use these techniques to construct hedgehogs of positive area and hedgehogs with inaccessible fixed points.

  14. Banks-Zaks fixed point analysis in momentum subtraction schemes

    NASA Astrophysics Data System (ADS)

    Gracey, J. A.; Simms, R. M.

    2015-04-01

    We analyze the critical exponents relating to the quark mass anomalous dimension and ? -function at the Banks-Zaks fixed point in quantum chromodynamics in a variety of representations for the quark in the momentum subtraction schemes of Celmaster and Gonsalves. For a specific range of values of the number of quark flavors, estimates of the exponents appear to be scheme independent. Using the recent five-loop modified minimal subtraction scheme, quark mass anomalous dimension, and estimates of the fixed point location, we estimate the associated exponent as 0.263-0.268 for the S U (3 ) color group and 12 flavors when the quarks are in the fundamental representation.

  15. An order theoretic approach in fixed point theory

    E-print Network

    Yaé Ulrich Gaba

    2014-11-07

    In the present article, we show the existence of a coupled fixed point for an order preserving mapping in a preordered left K-complete quasi-pseudometric space using a preorder induced by an appropriate function. We also define the concept of left-weakly related mappings on a preordered space and discuss common coupled fixed points for two and three left-weakly related mappings in the same space. Similar results are given for right-weakly related mappings, the dual notion of left-weakly related mappings.

  16. Disordered horizons: holography of randomly disordered fixed points.

    PubMed

    Hartnoll, Sean A; Santos, Jorge E

    2014-06-13

    We deform conformal field theories with classical gravity duals by marginally relevant random disorder. We show that the disorder generates a flow to IR fixed points with a finite amount of disorder. The randomly disordered fixed points are characterized by a dynamical critical exponent z > 1 that we obtain both analytically (via resummed perturbation theory) and numerically (via a full simulation of the disorder). The IR dynamical critical exponent increases with the magnitude of disorder, probably tending to z ? ? in the limit of infinite disorder. PMID:24972193

  17. Fixed Point Problems for Linear Transformations on Pythagorean Triples

    ERIC Educational Resources Information Center

    Zhan, M.-Q.; Tong, J.-C.; Braza, P.

    2006-01-01

    In this article, an attempt is made to find all linear transformations that map a standard Pythagorean triple (a Pythagorean triple [x y z][superscript T] with y being even) into a standard Pythagorean triple, which have [3 4 5][superscript T] as their fixed point. All such transformations form a monoid S* under matrix product. It is found that S*…

  18. Intuitionistic fixed point theories for strictly positive operators

    E-print Network

    Jäger, Gerhard

    Intuitionistic fixed point theories for strictly positive operators Christian R¨uede Thomas Strahm parameters. This generalizes results previously due to Buchholz [5] and Arai [2]. Keywords: Intuitionistic]. Not long ago it has been observed by Buchholz [5] that the choice of logic is crucial in the context

  19. Kadanoff Sand Pile Model Avalanches and Fixed Points

    E-print Network

    Liège, Université de

    Kadanoff Sand Pile Model Avalanches and Fixed Points K´evin Perrot and ´Eric R´emila ´equipe MC2 #12;Aim of this work 1 2 D-1 ... #12;Introduction Definition Representation Known results Avalanches Inductive computation Avalanche as a carry the Snowball Conjecture Statement Approach and issues #12

  20. New triple fixed point results in cone metric spaces

    NASA Astrophysics Data System (ADS)

    Abusalim, Sahar Mohammad; Noorani, Mohd Salmi Md

    2015-05-01

    The conception of c-distance on a cone metric space was introduced in 2011. In this paper, some tripled fixed points theorems for some type of contraction mapping are evidenced in a cone metric space by using this concept of c-distance. We also provide examples to illustrate our obtained results.

  1. A fixed point solution for convolved audio source separation

    Microsoft Academic Search

    Nikolaos Mitianoudis; Mike Davies

    2001-01-01

    We examine the problem of blind audio source separation using independent component analysis (ICA). In order to separate audio sources recorded in a real recording environment, we need to model the mixing process as convolutional. Many methods have been introduced for separating convolved mixtures, the most successful of which require working in the frequency domain. This paper proposes a fixed-point

  2. Fixed Point Theorems with Applications to Economics and Game Theory

    Microsoft Academic Search

    Kim C. Border

    1985-01-01

    One of the problems in economics that economists have devoted a considerable amount of attention in prevalent years has been to ensure consistency in the models they employ. Assuming markets to be generally in some state of equilibrium, it is asked under what circumstances such equilibrium is possible. The fundamental mathematical tools used to address this concern are fixed point

  3. HOMOLOGICAL METHODS IN FIXED POINT THEORY OF MULTIVALUED MAPPINGS

    Microsoft Academic Search

    Lech Górniewicz

    In this chapter we would like to present a systematic study of the fixed point theory for multivalued maps by using homological methods. Homological methods were initiated in 1946 by S. Eilenberg and D. Montgomery in their celebrated paper [EM]. Using methods of homology we can obtain stronger results than those obtained by means of the approximation methods as used

  4. APPROXIMATION METHODS IN FIXED POINT THEORY OF MULTIVALUED MAPPINGS

    Microsoft Academic Search

    Lech Górniewicz

    There are two significant sets of methods in the fixed point theory of multivalued mappings. The first are the so called homological methods, started in 1946 by S. Eilenberg and D. Montgomery ([EM]), and depend on using algebraic topology tools, e.g. homology theory, homotopy theory, etc. The second, started in 1935 by J. Von Neumann ([Neu]), are called the approximation

  5. Nielsen fixed point theory for partially ordered sets

    Microsoft Academic Search

    Peter Wong

    2001-01-01

    In this paper, we introduce a Nielsen type number N?(f,P) for any selfmap f of a partially ordered set P of spaces. This Nielsen theory relates to various existing Nielsen type fixed point theories for different settings such as maps of pairs of spaces, maps of triads, fibre preserving maps, equivariant maps and iterates of maps, by exploring their underlying

  6. Wess Zumino Couplings for Generalized Sigma Orbifold Fixed-points

    E-print Network

    Juan Fernando Ospina Giraldo

    2000-07-09

    The Wess-Zumino couplings for generalized sigma-orbifold fixed-points are presented and the generalized GS 6-form that encoding the complete sigma-standard gauge-gravitational-non standard gauge anomaly and its opposite inflow is derived.

  7. Wess Zumino Couplings for Generalized $\\Sigma$ Orbifold Fixed-points

    E-print Network

    Ospina-Giraldo, J F

    2000-01-01

    The Wess-Zumino couplings for generalized sigma-orbifold fixed-points are presented and the generalized GS 6-form that encoding the complete sigma-standard gauge-gravitational-non standard gauge anomaly and its opposite inflow is derived.

  8. Non-Thermal Fixed Point in a Holographic Superfluid

    E-print Network

    Carlo Ewerz; Thomas Gasenzer; Markus Karl; Andreas Samberg

    2015-05-11

    We study the far-from-equilibrium dynamics of a (2+1)-dimensional superfluid at finite temperature and chemical potential using its holographic description in terms of a gravitational system in 3+1 dimensions. Starting from various initial conditions corresponding to ensembles of vortex defects we numerically evolve the system to long times. At intermediate times the system exhibits Kolmogorov scaling the emergence of which depends on the choice of initial conditions. We further observe a universal late-time regime in which the occupation spectrum and different length scales of the superfluid exhibit scaling behaviour. We study these scaling laws in view of superfluid turbulence and interpret the universal late-time regime as a non-thermal fixed point of the dynamical evolution. In the holographic superfluid the non-thermal fixed point can be understood as a stationary point of the classical equations of motion of the dual gravitational description.

  9. Non-thermal fixed point in a holographic superfluid

    NASA Astrophysics Data System (ADS)

    Ewerz, Carlo; Gasenzer, Thomas; Karl, Markus; Samberg, Andreas

    2015-05-01

    We study the far-from-equilibrium dynamics of a (2 + 1)-dimensional super-fluid at finite temperature and chemical potential using its holographic description in terms of a gravitational system in 3 + 1 dimensions. Starting from various initial conditions corresponding to ensembles of vortex defects we numerically evolve the system to long times. At intermediate times the system exhibits Kolmogorov scaling the emergence of which depends on the choice of initial conditions. We further observe a universal late- time regime in which the occupation spectrum and different length scales of the superfluid exhibit scaling behaviour. We study these scaling laws in view of superfluid turbulence and interpret the universal late-time regime as a non-thermal fixed point of the dynamical evolution. In the holographic superfluid the non-thermal fixed point can be understood as a stationary point of the classical equations of motion of the dual gravitational description.

  10. Bifurcation of fixed points from a manifold of trivial fixed points in the infinite-dimensional case

    Microsoft Academic Search

    Massimo Furi; Mario Martelli; Maria Patrizia Pera

    2007-01-01

    .  We obtain a necessary as well as a sufficient condition for the existence of bifurcation points of a coincidence equation,\\u000a and, in particular, of a parametrized fixed point problem. In both cases the trivial solutions are assumed to form a finite-dimensional\\u000a submanifold of a Banach manifold. An application is given to a delay differential equation on a manifold: we detect

  11. Some generalizations of Caristi’s fixed point theorem with applications to the fixed point theory of weakly contractive set-valued maps and the minimization problem

    Microsoft Academic Search

    A. Amini-Harandi

    2010-01-01

    In this paper, we first prove some generalizations of Caristi’s fixed point theorem. Then we give some applications to the fixed point theory of weakly contractive set-valued maps and the minimization problem.

  12. Gravity Duals of Lifshitz-Like Fixed Points

    SciTech Connect

    Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Liu, Xiao; /Perimeter Inst. Theor. Phys.; Mulligan, Michael; /Stanford U., Phys. Dept. /SLAC

    2008-11-05

    We find candidate macroscopic gravity duals for scale-invariant but non-Lorentz invariant fixed points, which do not have particle number as a conserved quantity. We compute two-point correlation functions which exhibit novel behavior relative to their AdS counterparts, and find holographic renormalization group flows to conformal field theories. Our theories are characterized by a dynamical critical exponent z, which governs the anisotropy between spatial and temporal scaling t {yields} {lambda}{sup z}t, x {yields} {lambda}x; we focus on the case with z = 2. Such theories describe multicritical points in certain magnetic materials and liquid crystals, and have been shown to arise at quantum critical points in toy models of the cuprate superconductors. This work can be considered a small step towards making useful dual descriptions of such critical points.

  13. Quantum adiabatic evolution using fixed-point quantum search

    E-print Network

    Avatar Tulsi

    2015-04-19

    A quantum system can be evolved from the ground state of an initial Hamiltonian to that of a final Hamiltonian by adiabatically changing the Hamiltonian with respect to time. The system remains in the ground-state of time-changing Hamiltonian provided the change is slow enough. More precisely, if $g$ is the minimum energy gap between the ground state and other eigenstates of time-changing Hamiltonian then the evolution time must scale as the inverse square of $g$ for a successful evolution. Childs et al.~\\cite{childs} proposed an alternative, where the system is kept in the ground state of a time-changing Hamiltonian by doing measurements at suitably small enough time intervals. Their scheme is successful only if the time scales as the inverse cube of $g$, and thus the time-scaling is inferior to the adiabatic evolution. Here, we propose another alternative which is essentially similar to the Childs' scheme but uses the concept of fixed-point quantum search (FPQS) algorithm~\\cite{fixed1,fixed2} to recover the inverse-square time-scaling behaviour of adiabatic evolution. Our algorithm uses selective transformations of the unknown ground states and phase-estimation algorithm (PEA) is the main tool to approximate such selective transformations. Thus we demonstrate an important application of fixed-point quantum search which achieves monotonic convergence towards the desired final state.

  14. A FIXED-POINT MINIMUM ERROR ENTROPY ALGORITHM Seungju Han, Jose Principe

    E-print Network

    Slatton, Clint

    to be faster, more stable and step- size free. Fixed-Point algorithms in neural learning theory have receivedA FIXED-POINT MINIMUM ERROR ENTROPY ALGORITHM Seungju Han, Jose Principe CNEL, Department propose the Fixed-Point Minimum Error Entropy (Fixed-Point MEE) as an alternative to the Minimum Error

  15. J. fixed point theory appl. Online First c 2009 Birkhauser Verlag Basel/Switzerland

    E-print Network

    Weinberger, Shmuel

    J. fixed point theory appl. Online First c 2009 Birkh¨auser Verlag Basel/Switzerland DOI 10.1007/s11784-009-0112-y Journal of Fixed Point Theory and Applications Fixed-point theories on noncompact three noncompact variants of Lefschetz­Nielsen fixed-point theory parallel to developments that have

  16. Banks-Zaks fixed point analysis in momentum subtraction schemes

    E-print Network

    Gracey, J A

    2015-01-01

    We analyse the critical exponents relating to the quark mass anomalous dimension and beta-function at the Banks-Zaks fixed point in Quantum Chromodynamics (QCD) in a variety of representations for the quark in the momentum subtraction (MOM) schemes of Celmaster and Gonsalves. For a specific range of values of the number of quark flavours, estimates of the exponents appear to be scheme independent. Using the recent five loop modified minimal subtraction (MSbar) scheme quark mass anomalous dimension and estimates of the fixed point location we estimate the associated exponent as 0.263-0.268 for the SU(3) colour group and 12 flavours when the quarks are in the fundamental representation.

  17. Inertially referenced pointing for body-fixed payloads

    NASA Astrophysics Data System (ADS)

    Germann, Lawrence M.; Gupta, Avanindra A.

    1990-10-01

    Important considerations are given in connection with achieving submicroradian jitter for body-fixed payloads employing inertial reference sensors. The derivation of the requirements, key design aspects, and specifications for important components are treated. The submicroradian-level pointing system for use on the body-fixed telescope (BFT) is described, emphasizing line-of-sight (LOS) jitter application. The pointing subsystem design is described. The BFT is tested on a motion table and shaker table, and compared with a simulation of LOS jitter due to base motion. Performance expectations are verified by the testbed, and are shown to vary from predicted results by less than 10 dB at all frequencies. A submicroradian-jitter stabilization subsystem may be built with qualified components that are presently available.

  18. On String Theory Duals of Lifshitz-like Fixed Points

    E-print Network

    Tatsuo Azeyanagi; Wei Li; Tadashi Takayanagi

    2009-05-06

    We present type IIB supergravity solutions which are expected to be dual to certain Lifshitz-like fixed points with anisotropic scale invariance. They are expected to describe a class of D3-D7 systems and their finite temperature generalizations are straightforward. We show that there exist solutions that interpolate between these anisotropic solutions in the IR and the standard AdS5 solutions in the UV. This predicts anisotropic RG flows from familiar isotropic fixed points to anisotropic ones. In our case, these RG flows are triggered by a non-zero theta-angle in Yang-Mills theories that linearly depends on one of the spatial coordinates. We study the perturbations around these backgrounds and discuss the possibility of instability. We also holographically compute their thermal entropies, viscosities, and entanglement entropies.

  19. Banks-Zaks fixed point analysis in momentum subtraction schemes

    E-print Network

    J. A. Gracey; R. M. Simms

    2015-04-01

    We analyse the critical exponents relating to the quark mass anomalous dimension and beta-function at the Banks-Zaks fixed point in Quantum Chromodynamics (QCD) in a variety of representations for the quark in the momentum subtraction (MOM) schemes of Celmaster and Gonsalves. For a specific range of values of the number of quark flavours, estimates of the exponents appear to be scheme independent. Using the recent five loop modified minimal subtraction (MSbar) scheme quark mass anomalous dimension and estimates of the fixed point location we estimate the associated exponent as 0.263-0.268 for the SU(3) colour group and 12 flavours when the quarks are in the fundamental representation.

  20. Fixed points, stable manifolds, weather regimes, and their predictability

    DOE PAGESBeta

    Deremble, Bruno; D'Andrea, Fabio; Ghil, Michael

    2009-01-01

    In a simple, one-layer atmospheric model, we study the links between low-frequency variability and the model’s fixed points in phase space. The model dynamics is characterized by the coexistence of multiple ''weather regimes.'' To investigate the transitions from one regime to another, we focus on the identification of stable manifolds associated with fixed points. We show that these manifolds act as separatrices between regimes. We track each manifold by making use of two local predictability measures arising from the meteorological applications of nonlinear dynamics, namely, ''bred vectors'' and singular vectors. These results are then verified in the framework of ensemblemore »forecasts issued from clouds (ensembles) of initial states. The divergence of the trajectories allows us to establish the connections between zones of low predictability, the geometry of the stable manifolds, and transitions between regimes.« less

  1. Fixed point structure of quenched, planar quantum electrodynamics

    SciTech Connect

    Love, S.T.

    1986-07-01

    Gauge theories exhibiting a hierarchy of fermion mass scales may contain a pseudo-Nambu-Boldstone boson of spontaneously broken scale invariance. The relation between scale and chiral symmetry breaking is studied analytically in quenched, planar quantum electrodynamics in four dimensions. The model possesses a novel nonperturbative ultraviolet fixed point governing its strong coupling phase which requires the mixing of four fermion operators. 12 refs.

  2. A fixed point approach to stability of a quadratic equation

    Microsoft Academic Search

    M. Mirzavaziri; M. S. Moslehian

    2006-01-01

    .  Using the fixed point alternative theorem we establish the orthogonal stability of the quadratic functional equation of Pexider\\u000a type f (x+y)+g(x?y) = h(x)+k(y), where f, g, h, k are mappings from a symmetric orthogonality space to a Banach space, by orthogonal additive mappings under a necessary and\\u000a sufficient condition on f.

  3. STABILITY BY FIXED POINT THEORY OR LIAPUNOV THEORY: A COMPARISON

    Microsoft Academic Search

    T. A. Burton

    Abstract. Liapunov’s direct method has been very eective,in establishing stability results for a wide variety of dierential equations. Yet, there is a large set of problems for which it has been ineective.,In a series of papers we have examined particular problems which have oered,great diculities,for that theory and have presented solutions by means of various fixed point theorems. In this

  4. Transfinite methods in metric fixed-point theory

    Microsoft Academic Search

    W. A. Kirk

    This is a brief survey of the use of transfinite induction in metric fixed-point theory. Among the results discussed in some detail is the author's 1989 result on directionally nonexpansive mappings (which is somewhat sharpened), a result of Kulesza and Lim giving conditions when\\u000acountable compactness implies compactness, a recent inwardness result for contractions due to Lim, and a recent

  5. A fixed-point DSP for graphics engines

    Microsoft Academic Search

    M. Johnson

    1989-01-01

    The use of the 16-bit ADSP-2100 digital signal microprocessor as a fixed-point, low-end graphics engine for applications such as video games and small computer graphics packages is examined. It serves as the basis for a complete, hardware-oriented approach to performing graphics operations on a 3-D database. Normalization and formatting are performed to avoid overflow and preserve data formats through the

  6. Fix-point Multiplier Distributions in Discrete Turbulent Cascade Models

    E-print Network

    B. Jouault; M. Greiner; P. Lipa

    1998-11-27

    One-point time-series measurements limit the observation of three-dimensional fully developed turbulence to one dimension. For one-dimensional models, like multiplicative branching processes, this implies that the energy flux from large to small scales is not conserved locally. This then renders the random weights used in the cascade curdling to be different from the multipliers obtained from a backward averaging procedure. The resulting multiplier distributions become solutions of a fix-point problem. With a further restoration of homogeneity, all observed correlations between multipliers in the energy dissipation field can be understood in terms of simple scale-invariant multiplicative branching processes.

  7. On Existence of Nontrivial Fixed Points in Large $N$ Gauge Theory in More than Four Dimensions

    E-print Network

    Jun Nishimura

    1996-08-22

    Inspired by a possible relation between large $N$ gauge theory and string theory, we search for nontrivial fixed points in large $N$ gauge theory in more than four dimensions. We study large $N$ gauge theory through Monte Carlo simulation of the twisted Eguchi-Kawai model in six dimensions as well as in four dimensions. The phase diagram of the system with the two coupling constants which correspond to the standard plaquette action and the adjoint term has been explored.

  8. Lecture 5: The Reduction, Periodicity and Fixed Point Theorems A solution to the Arf-Kervaire

    E-print Network

    Ravenel, Douglas

    concept from equivariant stable homotopy theory, that of geometric fixed points. 5.2 2 Geometric fixedLecture 5: The Reduction, Periodicity and Fixed Point Theorems A solution to the Arf and ~hC8 are equivalent, the Fixed Point Theorem. Before we can do this, we need to introduce another

  9. Queueing delay - error probability tradeoff for point-to-point channels with fixed length block codes

    Microsoft Academic Search

    Vineeth Bala Sukumaran; Utpal Mukherji

    2011-01-01

    We study the tradeoff between the average error probability and the average queueing delay of messages which randomly arrive to the transmitter of a point-to-point discrete memoryless channel that uses variable rate fixed codeword length random coding. Bounds to the exponential decay rate of the average error probability with average queueing delay in the regime of large average delay are

  10. Automatic Conversion of Floating Point MATLAB Programs into Fixed Point FPGA Based Hardware Design

    Microsoft Academic Search

    Prithviraj Banerjee; Debabrata Bagchi; Malay Haldar; Anshuman Nayak; Victor Kim; R. Uribe

    2003-01-01

    This paper describes how the floating point computations in MATLAB can be automatically converted to a fixed point MATLAB version of specific precision for hardware design. The techniques have been incorporated in the AcelFPGA behavioral synthesis tool (Banerjee et al., 2003) that reads in high-level descriptions of DSP applications written in MATLAB, and automatically generate synthesizable RTL models in VHDL

  11. A comparison of roundoff noise in floating point and fixed point digital filter realizations

    Microsoft Academic Search

    C. Weinstein; A. V. Oppenheim

    1969-01-01

    A statistical model for roundoff noise in floating point digital filters, proposed by Kaneko and Liu, is tested experimentally for first- and second-order digital filters. Good agreement between theory and experiment is obtained. The model is used to specify a comparison between floating point and fixed point digital filter realizations on the basis of their output noise-to-signal ratio, and curves

  12. (0, 2) SCFTs from the Leigh-Strassler fixed point

    NASA Astrophysics Data System (ADS)

    Bobev, Nikolay; Pilch, Krzysztof; Vasilakis, Orestis

    2014-06-01

    We show that there is a family of two-dimensional (0, 2) SCFTs associated with twisted compactifications of the four-dimensional = 1 Leigh-Strassler fixed point on a closed hyperbolic Riemann surface. We calculate the central charges for this class of theories using anomalies and c-extremization. In a suitable truncation of the five-dimensional maximal supergravity, we construct supersymmetric AdS 3 solutions that are holographic duals of those two-dimensional (0, 2) SCFTs. We also exhibit supersymmetric domain wall solutions that are holographically dual to the RG flows between the four-dimensional and two-dimensional theories.

  13. Chapter 7 Fixed point theory and elliptic boundary value problems

    Microsoft Academic Search

    Henghui Zou

    2008-01-01

    Let ? ? Rn be a bounded smooth domain. For k > 1, consider the following non-linear elliptic boundary value problem (I)÷Al(x,u,Du)+fl(x,u,Du)=0in?,l=1,...,k,u(x)=u0(x),on??, where u:??Rk,fl:?×Rk×Rnk?RAl:?×Rk×Rnk?Rn,l=1,...,k, are vector-valued functions. Under appropriate conditions on the functions fl and Al, we investigate the question of existence of positive solutions to the boundary value problem (I) via the fixed point theory. The a priori estimates

  14. Infrared Fixed Points in the minimal MOM Scheme

    E-print Network

    Thomas A. Ryttov

    2014-03-17

    We analyze the behavior of several renormalization group functions at infrared fixed points for $SU(N)$ gauge theories with fermions in the fundamental and two-indexed representations. This includes the beta function of the gauge coupling, the anomalous dimension of the gauge parameter and the anomalous dimension of the mass. The scheme in which the analysis is performed is the minimal momentum subtraction scheme through third loop order. Due to the fact that scheme dependence is inevitable once the perturbation theory is truncated we compare to previous identical studies done in the minimal subtraction scheme and the modified regularization invariant scheme. We find only mild to moderate scheme dependence.

  15. FIXED POINT THEORY FOR MULTIVALUED OPERATORS ON A SET WITH TWO METRICS

    Microsoft Academic Search

    ADRIAN PETRUSEL; IOAN A. RUS

    2007-01-01

    The purpose of this work is to present some fixed point results for multivalued operators on a set with two metrics. A multivalued version of Maia's fixed point theorem is proved. The data dependence and the well-posedness of the fixed point problem are also discussed. Some extensions to generalized multivalued contractions are pointed out.

  16. Fate of CPN-1 Fixed Points with q Monopoles

    NASA Astrophysics Data System (ADS)

    Block, Matthew S.; Melko, Roger G.; Kaul, Ribhu K.

    2013-09-01

    We present an extensive quantum Monte Carlo study of the Néel to valence-bond solid (VBS) phase transition on rectangular- and honeycomb-lattice SU(N) antiferromagnets in sign-problem-free models. We find that in contrast to the honeycomb lattice and previously studied square-lattice systems, on the rectangular lattice for small N, a first-order Néel-VBS transition is realized. On increasing N?4, we observe that the transition becomes continuous and with the same universal exponents as found on the honeycomb and square lattices (studied here for N=5, 7, 10), providing strong support for a deconfined quantum critical point. Combining our new results with previous numerical and analytical studies, we present a general phase diagram of the stability of CPN-1 fixed points with q monopoles.

  17. Area law for fixed points of rapidly mixing dissipative quantum systems

    E-print Network

    Fernando G. S. L. Brandao; Toby S. Cubitt; Angelo Lucia; Spyridon Michalakis; David Perez-Garcia

    2015-05-11

    We prove an area law for the mutual information for fixed points of local dissipative quantum system satisfying a rapid mixing condition, under either of the following assumptions: the fixed point is pure, or the system is frustration free.

  18. FIXED POINT THEORY FOR MULTIVALUED GENERALIZED CONTRACTION ON A SET WITH TWO b-METRICS

    Microsoft Academic Search

    MONICA BORICEANU

    The purpose of this paper is to present some fixed point results for multivalued generalized contraction on a set with two b-metrics. The data dependence and the well-posedness of the fixed point problem are also discussed.

  19. Fixed-point error analysis of Winograd Fourier transform algorithms

    NASA Technical Reports Server (NTRS)

    Patterson, R. W.; Mcclellan, J. H.

    1978-01-01

    The quantization error introduced by the Winograd Fourier transform algorithm (WFTA) when implemented in fixed-point arithmetic is studied and compared with that of the fast Fourier transform (FFT). The effect of ordering the computational modules and the relative contributions of data quantization error and coefficient quantization error are determined. In addition, the quantization error introduced by the Good-Winograd (GW) algorithm, which uses Good's prime-factor decomposition for the discrete Fourier transform (DFT) together with Winograd's short length DFT algorithms, is studied. Error introduced by the WFTA is, in all cases, worse than that of the FFT. In general, the WFTA requires one or two more bits for data representation to give an error similar to that of the FFT. Error introduced by the GW algorithm is approximately the same as that of the FFT.

  20. A Fixed-Point Iteration Method with Quadratic Convergence

    SciTech Connect

    Walker, Kevin P. [Engineering Science Software, Inc.; Sham, Sam [ORNL

    2012-01-01

    The fixed-point iteration algorithm is turned into a quadratically convergent scheme for a system of nonlinear equations. Most of the usual methods for obtaining the roots of a system of nonlinear equations rely on expanding the equation system about the roots in a Taylor series, and neglecting the higher order terms. Rearrangement of the resulting truncated system then results in the usual Newton-Raphson and Halley type approximations. In this paper the introduction of unit root functions avoids the direct expansion of the nonlinear system about the root, and relies, instead, on approximations which enable the unit root functions to considerably widen the radius of convergence of the iteration method. Methods for obtaining higher order rates of convergence and larger radii of convergence are discussed.

  1. Fixed point of second virial coefficients in the glass transition

    E-print Network

    Jialin Wu

    2007-01-16

    Classical thermodynamic theory still holds true in subsystem that is a percolation connected by 8 orders of self-similar 2-body-3-body coupling clusters. The fixed point, $B_2^* \\equiv 3/8$, for the clusters of different size, existing in reduced second Virial coefficients has been proved by scaling theory in percolation field. It is shown that, if $B_2^* \\equiv 3/8$ is combined with $B_3^* \\equiv 5/8$, the potentials of 2-body-3-body coupling clusters, in critical local cluster growth phase transition, balance the kinetic energy in the glass transition. It is also proved that the glass transition corresponds to the regime in which the chemical potentials in all subsystems hold zero.

  2. A Fixed Point Analysis of a Gene Pool GA with Mutation Alden H. Wright #

    E-print Network

    Wright, Alden H.

    recombination, selection, and mutation. We find and rigorously prove the stability of fixed points whiA Fixed Point Analysis of a Gene Pool GA with Mutation Alden H. Wright # Computer Science # is the string length. For linear fitness functions, we show that there is a single fixed point

  3. A methodology and design environment for DSP ASIC fixed point refinement

    Microsoft Academic Search

    Radim Cmar; Luc Rijnders; Patrick Schaumont; Serge Vernalde; Ivo Bolsens

    1999-01-01

    Complex signal processing algorithms are specified in floating point precision. When their hardware implemen- tation requires fixed point precision, type refinement is needed. The paper presents a methodology and design en- vironment for this quantization process. The method uses independent strategies for fixing MSB and LSB weights of fixed point signals. It enables short de- sign cycles by combining the

  4. Fixed point theory for generalized quasicontraction maps in vector modular spaces

    Microsoft Academic Search

    A. Amini-Harandi

    2011-01-01

    In this paper, we introduce vector modular spaces and prove the existence of fixed points for generalized quasicontraction maps and discuss their uniqueness in these spaces. Our fixed point theorem, even in the case of modular spaces, extends the main result of Khamsi [M.A. Khamsi, Quasicontraction mappings in modular spaces without ?2-condition, Fixed Point Theory and Applications 2008, 6 pages,

  5. ON GUPTABELNAP REVISION THEORIES OF TRUTH, KRIPKEAN FIXED POINTS, AND THE NEXT STABLE SET.

    E-print Network

    Welch, Philip

    ON GUPTA­BELNAP REVISION THEORIES OF TRUTH, KRIPKEAN FIXED POINTS, AND THE NEXT STABLE SET. P regarded as an alternative approach to the Kripkean theory of fixed points via monotone inductive operators, Kripkean fixed points. We should like to express our gratitude to the Department of Mathematics

  6. ON GUPTA-BELNAP REVISION THEORIES OF TRUTH, KRIPKEAN FIXED POINTS, AND THE NEXT STABLE SET.

    E-print Network

    Welch, Philip

    ON GUPTA-BELNAP REVISION THEORIES OF TRUTH, KRIPKEAN FIXED POINTS of truth has sometimes been regarded as an alternative approach to the Kripkean theory of fixed points via that the stable sets arising in such sequences are none other than Kripkean fixed points

  7. Fixed point structure of supersymmetric O(N) theories Tobias Hellwig

    E-print Network

    Rossak, Wilhelm R.

    Fixed point structure of supersymmetric O(N) theories Tobias Hellwig FS University Jena PAF TPI 24.09.2012 Tobias Hellwig (TPI FSU Jena) Fixed point of O(N) theories 24.09.2012 1 / 19 #12;Table of contents 1 Hellwig (TPI FSU Jena) Fixed point of O(N) theories 24.09.2012 3 / 19 #12;Physical fundamentals

  8. Computational fixed point theory for differential delay equations with multiple time lags

    E-print Network

    Lessard, Jean-Philippe

    Computational fixed point theory for differential delay equations with multiple time lags Jean nontrivial periodic solutions for a delay equation with three time lags. 1 Introduction Fixed point theory, that we describe here as computational fixed point theory, to the context of proving, in a direct

  9. The renormalization fixed point as a mathematical object R. P. Langlands

    E-print Network

    Langlands, Robert

    charge c = 1/2. The data defining this field theory must be present in the coordinates of the fixed pointThe renormalization fixed point as a mathematical object R. P. Langlands 1. Introduction directions, often just one or two, at the pertinent fixed point of the associated infinite

  10. Fixed point theories and dependent choice Gerhard Jager and Thomas Strahm

    E-print Network

    Jäger, Gerhard

    Fixed point theories and dependent choice Gerhard J¨ager and Thomas Strahm Abstract In this paper for this paper are (i) Avigad's fixed point theory FP 0 (see Avigad [1]) and (ii) the recent work in metapredicativity about transfinitely iterated fixed point theories (see J¨ager, Kahle, Setzer, Strahm [12]). Avigad

  11. Fixed point theory in cone metric spaces obtained via the scalarization method

    Microsoft Academic Search

    A. Amini-Harandi; M. Fakhar

    2010-01-01

    Motivated by the scalarization method in vector optimization theory, we take a new approach to fixed point theory on cone metric spaces. By using our method we prove some fixed point theorems and several common fixed point theorems on cone metric spaces in which the cone need not be normal. Our results improve and generalize many well-known results from the

  12. Lecture 6: Fixed Points and elements of Domain theory Consider recursive definition of gcd

    E-print Network

    Rabinovich, Alexander

    Lecture 6: Fixed Points and elements of Domain theory 1 Example Consider recursive definition semantics is the least fixed point of the functional GCD with respect to the partial order #18; between functions. The program computes the least h such that GCD(h) = h. 2 Fixed points in the space of partial

  13. ON GUPTA-BELNAP REVISION THEORIES OF TRUTH, KRIPKEAN FIXED POINTS, AND THE NEXT STABLE SET.

    E-print Network

    Welch, Philip

    ON GUPTA-BELNAP REVISION THEORIES OF TRUTH, KRIPKEAN FIXED POINTS, AND THE NEXT STABLE SET. P regarded as an alternative approach to the Kripkean theory of fixed points via monotone inductive operators, Kripkean fixed points. We should like to express our gratitude to the Department of Mathematics

  14. A method to combine chaos and neural network based on the fixed point theory

    Microsoft Academic Search

    D. Zhou; K. Yasuda; R. Yokoyama

    1997-01-01

    The dynamics of either associative or hierarchical neural network can boil down to the discovery of fixed point or contraction to the already established fixed point in a discrete dynamical system, and strict mathematical calculations have already proven this point. In other words, the dynamics of all types of neural network can be analyzed and explained by using the fixed

  15. of the Markov-Kakutani fixed point theorem via the Hahn-Banach theorem

    E-print Network

    Werner, Dirk

    : General Theory. Interscience Publishers, New York, 1958. [2] S. Kakutani. Two fixed-point theoremsA proof of the Markov-Kakutani fixed point theorem via the Hahn-Banach theorem Dirk Werner S. Kakutani, in [2] and [3], provides a proof of the Hahn-Banach theorem via the Markov-Kakutani fixed point

  16. On the Complexity of Nash Equilibria and Other Fixed Points Kousha Etessami

    E-print Network

    Etessami, Kousha

    , and probability theory, can be cast as fixed point problems for such algebraic functions. We discuss severalOn the Complexity of Nash Equilibria and Other Fixed Points Kousha Etessami LFCS, School to compute a fixed point of a given Brouwer function, and we investigate the complexity of the associated

  17. FIXED POINT THEORY AND THE K -THEORETIC TRACE Ross Geoghegan* and Andrew Nicas**

    E-print Network

    Geoghegan, Ross

    FIXED POINT THEORY AND THE K -THEORETIC TRACE Ross Geoghegan between fixed point theory and K -theory is exp* *lained, both classical Nielsen theory (versus K0) and 1-parameter fixed point theory (v* *ersus K1). In particular, various zeta functions

  18. Recent Applications of Proof Theory in Fixed Point and Ergodic Theory

    E-print Network

    Recent Applications of Proof Theory in Fixed Point and Ergodic Theory Ulrich Kohlenbach Department in a primitive recursive bound. Recent Applications of Proof Theory in Fixed Point and Ergodic Theory #12;Logical of assumptions (e.g. compactness). Recent Applications of Proof Theory in Fixed Point and Ergodic Theory #12

  19. Synthesis of Optimal Fixed-Point Implementation of Numerical Software Routines

    E-print Network

    Seshia, Sanjit A.

    theory. For the control theory examples, we not only exhibit the synthesized fixed-point programsSynthesis of Optimal Fixed-Point Implementation of Numerical Software Routines Susmit Jha1-environments such as Matlab. However, these designs are often implemented using fixed-point arithmetic for speed

  20. On the relationship between fixed points and iteration in admissible set theory without

    E-print Network

    Jäger, Gerhard

    On the relationship between fixed points and iteration in admissible set theory without foundation). Hence the relationship between fixed points and iteration persists in the framework of set theory In classical set theory, the relationship between fixed points and iteration is evident. Given a monotone

  1. The Fixed-Point Theory of Strictly Causal Functions Eleftherios Matsikoudis

    E-print Network

    The Fixed-Point Theory of Strictly Causal Functions Eleftherios Matsikoudis Edward A. Lee: Bosch, National Instruments, and Toyota. #12;The Fixed-Point Theory of Strictly Causal Functions induces a fixed-point constraint on the function modelling the component involved. We define strictly

  2. A SHARP LOWER BOUND ON FIXED POINTS OF SURFACE SYMPLECTOMORPHISMS IN EACH MAPPING CLASS

    E-print Network

    Cotton-Clay, Andrew

    -area-preserving maps on sur- faces, comes from Nielsen theory. The Nielsen class 0((M)) of a fixed point x of a mapA SHARP LOWER BOUND ON FIXED POINTS OF SURFACE SYMPLECTOMORPHISMS IN EACH MAPPING CLASS ANDREW obtain sharp lower bounds on the number of fixed points of a surface symplectomorphism (i.e. area

  3. Fixed Points, Nash Equilibria, and the Existential Theory of the Reals

    E-print Network

    Schaefer, Marcus

    Fixed Points, Nash Equilibria, and the Existential Theory of the Reals Marcus Schaefer School in the existential theory of the reals, and so solution sets do not necessarily contain rational points: the fixed problems; we show that the complexity of decision variants of fixed-point problems, including Nash

  4. A Comparison of the Commonsense and Fixed Point Theories of Nonmonotonicity

    Microsoft Academic Search

    Frank Brown

    1986-01-01

    The mathematical fixed point theories of nonmonotonic reasoning are examined and compared to a commonsense theory of nonmonotonic reasoning which models our intuitive ability to reason about defaults. It is shown that all of the known problems of the fixed point theories are solved by the commonsense theory. The concepts of this commonsense theory do not involve mathematical fixed points,

  5. Standard map in magnetized relativistic systems: Fixed points and regular acceleration

    SciTech Connect

    Sousa, M. C. de; Steffens, F. M.; Pakter, R.; Rizzato, F. B. [Departamento de Fisica-NFC, Universidade Prebisteriana Mackenzie, Rua da Consolacao 930, 01302-906 Sao Paulo, SP (Brazil); Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970, Porto Alegre, RS (Brazil)

    2010-08-15

    We investigate the concept of a standard map for the interaction of relativistic particles and electrostatic waves of arbitrary amplitudes, under the action of external magnetic fields. The map is adequate for physical settings where waves and particles interact impulsively, and allows for a series of analytical result to be exactly obtained. Unlike the traditional form of the standard map, the present map is nonlinear in the wave amplitude and displays a series of peculiar properties. Among these properties we discuss the relation involving fixed points of the maps and accelerator regimes.

  6. LOCAL FIXED POINT THEORY FOR THE SUM OF TWO OPERATORS IN BANACH SPACES

    Microsoft Academic Search

    B. C. DHAGE

    2003-01-01

    The present paper studies the local version of the well-known fixed point theo- rems of Krasnoselskii (5) and Nashed and Wong (5). Some applications of newly developed local fixed point theorems to nonlinear functional integral equations of fixed type are also discussed.

  7. Fixed point Open Ocean Observatory network (FixO3): Multidisciplinary observations from the air-sea interface to the deep seafloor

    NASA Astrophysics Data System (ADS)

    Lampitt, Richard; Cristini, Luisa

    2014-05-01

    The Fixed point Open Ocean Observatory network (FixO3) seeks to integrate the 23 European open ocean fixed point observatories and to improve access to these key installations for the broader community. These will provide multidisciplinary observations in all parts of the oceans from the air-sea interface to the deep seafloor. Coordinated by the National Oceanography Centre, UK, FixO3 builds on the significant advances achieved through the previous Europe-funded FP7 programmes EuroSITES, ESONET and CARBOOCEAN. Started in September 2013 with a budget of 7 Million Euros over 4 years the project has 29 partners drawn from academia, research institutions and SME's. In addition 12 international experts from a wide range of disciplines comprise an Advisory Board. On behalf of the FixO3 Consortium, we present the programme that will be achieved through the activities of 12 Work Packages: 1. Coordination activities to integrate and harmonise the current procedures and processes. Strong links will be fostered with the wider community across academia, industry, policy and the general public through outreach, knowledge exchange and training. 2. Support actions to offer a) free access to observatory infrastructures to those who do not have such access, and b) free and open data services and products. 3. Joint research activities to innovate and enhance the current capability for multidisciplinary in situ ocean observation. Support actions include Transnational Access (TNA) to FixO3 infrastructure, meaning that European organizations can apply to free-of-charge access to the observatories for research and testing in two international calls during the project lifetime. The first call for TNA opens in summer 2014. More information can be found on FixO3 website (www.fixo3.eu/). Open ocean observation is currently a high priority for European marine and maritime activities. FixO3 will provide important data on environmental products and services to address the Marine Strategy Framework Directive and in support of the European Integrated Maritime Policy. The FixO3 network will provide free and open access to in situ fixed point data of the highest quality. It will provide a strong integrated framework of open ocean facilities in the Atlantic from the Arctic to the Antarctic and throughout the Mediterranean, enabling an integrated, regional and multidisciplinary approach to understand natural and anthropogenic change in the ocean.

  8. Gauge invariant and gauge fixed actions for various higher-spin fields from string field theory

    E-print Network

    Masako Asano

    2012-09-18

    We propose a systematic procedure for extracting gauge invariant and gauge fixed actions for various higher-spin gauge field theories from covariant bosonic open string field theory. By identifying minimal gauge invariant part for the original free string field theory action, we explicitly construct a class of covariantly gauge fixed actions with BRST and anti-BRST invariance. By expanding the actions with respect to the level N of string states, the actions for various massive fields including higher-spin fields are systematically obtained. As illustrating examples, we explicitly investigate the level Nactions for massive graviton field, massive 3rd rank symmetric tensor field, or antisymmetric field. We also investigate the tensionless limit of the actions and explicitly derive the gauge invariant and gauge fixed actions for general rank n symmetric and anti-symmetric tensor fields.

  9. Fixed Points and elements of Domain theory continuation 1 Examples Context free Grammars

    E-print Network

    Rabinovich, Alexander

    Fixed Points and elements of Domain theory ­continuation 1 Examples ­ Context free Grammars 1. E = #15; j aE 2. E = a j bEb 3. E = #15; j aaEE One can use fixed point theorem to provide the semanticsX is continuous; X #26; fag S fbgXfbg is continuous. Therefore, these functions have the least fixed points

  10. Topological Methods in the Fixed-Point Theory of Multi-Valued Maps

    Microsoft Academic Search

    Yu G. Borisovich; B. D. Gel'man; A. D. Myshkis; V. V. Obukhovskii

    1980-01-01

    CONTENTSIntroduction Chapter I. Approximative methods in the fixed-point theory of multi-valued maps § 1.1. Multi-valued maps and single-valued approximations § 1.2. The rotation of multi-valued vector fields with convex images and fixed-point theorems § 1.3. Obstruction theory and single-valued approximations of multi-valued maps § 1.4. Guide to the literature in Chapter I Chapter II. Homological methods in the fixed-point theory

  11. TOPOLOGICAL METHODS IN THE FIXED-POINT THEORY OF MULTI-VALUED MAPS

    Microsoft Academic Search

    Yu G Borisovich; B D Gelman; A D Myshkis; V V Obukhovskii

    1980-01-01

    CONTENTSIntroduction Chapter I. Approximative methods in the fixed-point theory of multi-valued maps § 1.1. Multi-valued maps and single-valued approximations § 1.2. The rotation of multi-valued vector fields with convex images and fixed-point theorems § 1.3. Obstruction theory and single-valued approximations of multi-valued maps § 1.4. Guide to the literature in Chapter I Chapter II. Homological methods in the fixed-point theory

  12. INVOLUTIONS ON TORI WITH CODIMENSION-ONE FIXED POINT SET ALLAN L. EDMONDS

    E-print Network

    Edmonds, Allan

    . Secondary 57R67. Key words and phrases. Smith theory, torus, involution, fixed point set . 1 #12;2 ALLAN L theory, the fixed point set F of G acting on Rn is a Zp-acyclic Zp-homology k-manifold for some k nINVOLUTIONS ON TORI WITH CODIMENSION-ONE FIXED POINT SET ALLAN L. EDMONDS ABSTRACT. The standard P

  13. Arnowitt-Deser-Misner gravity with variable G and Lambda and fixed point cosmologies from the renormalization group

    E-print Network

    Alfio Bonanno; Giampiero Esposito; Claudio Rubano

    2004-09-27

    Models of gravity with variable G and Lambda have acquired greater relevance after the recent evidence in favour of the Einstein theory being nonperturbatively renormalizable in the Weinberg sense. The present paper applies the Arnowitt-Deser-Misner (ADM) formalism to such a class of gravitational models. Are modified action functional is then built which reduces to the Einstein-Hilbert action when G is constant, and leads to a power-law growth of the scale factor for pure gravity and for a massless Phi**4 theory in a Universe with Robertson-Walker symmetry, in agreement with the recently developed fixed-point cosmology. Interestingly, the renormalization-group flow at the fixed point is found to be compatible with a Lagrangian description of the running quantities G and Lambda.

  14. An Improved Multi-Objective Genetic Algorithm Based On Pareto Front and Fixed Point Theory

    Microsoft Academic Search

    Jingjun Zhang; Yanmin Shang; Ruizhen Gao; Yuzhen Dong

    2009-01-01

    For multi-objective optimization problems, an improved multi-objective genetic algorithm based on Pareto Front and Fixed Point Theory is proposed in this paper. In this Algorithm, the fixed point theory is introduced to multi-objective optimization questions and K1 triangulation is carried on to solutions for the weighting function constructed by all sub- functions, so the optimal problems are transferred to fixed

  15. Stability of fixed points and generalized critical behavior in multifield models

    E-print Network

    Astrid Eichhorn; David Mesterházy; Michael M. Scherer

    2014-11-20

    We study models with three coupled vector fields characterized by $O(N_1)\\oplus O(N_2) \\oplus O(N_3)$ symmetry. Using the nonperturbative functional renormalization group, we derive $\\beta$ functions for the couplings and anomalous dimensions in $d$ dimensions. Specializing to the case of three dimensions, we explore interacting fixed points that generalize the $O(N)$ Wilson-Fisher fixed point. We find a symmetry-enhanced isotropic fixed point, a large class of fixed points with partial symmetry enhancement, as well as partially and fully decoupled fixed point solutions. We discuss their stability properties for all values of $N_1, N_2$, and $N_3$, emphasizing important differences to the related two-field models. For small numbers of field components we find no stable fixed point solutions, and we argue that this can be attributed to the presence of a large class of possible (mixed) couplings in the three-field and multifield models. Furthermore, we contrast different mechanisms for stability interchange between fixed points in the case of the two- and three-field models, which generically proceed through fixed-point collisions.

  16. ANDERSON ACCELERATION FOR FIXED-POINT ITERATIONS HOMER F. WALKER AND PENG NI

    E-print Network

    Walker, Homer F.

    ANDERSON ACCELERATION FOR FIXED-POINT ITERATIONS HOMER F. WALKER AND PENG NI Abstract. This paper concerns an acceleration method for fixed-point iterations that originated in work of D. G. Anderson-560], which we accordingly call Anderson acceleration here. This method has enjoyed considerable success

  17. EA Models and Population Fixed-Points Versus Mutation Rates for Functions of Unitation

    E-print Network

    Wright, Alden H.

    EA Models and Population Fixed-Points Versus Mutation Rates for Functions of Unitation J Neal theory of evolutionary algorithms, infinite population models, unitation functions, fixed points, genetic algorithms. 1. INTRODUCTION The Vose infinite population model [1] of simple genetic algorithms is a dynamic

  18. Fixed point theorems in the Arnol'd model about instability of the actionvariables in phasespace

    E-print Network

    Perfetti, Paolo

    ' 2 +cos t)) I 2 R 2 (``Arnol'd model about diffusion''); by means of fixed point theorems tools suggested by Arnol'd i.e. the contraction mapping method togheter with the ``conical metric: Arnold diffusion, whiskers, Poincar'e map, fixed point theorem, stable manifold, unstable manifold

  19. A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties

    E-print Network

    A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties Jeffrey R@ipst.umd.edu #12;1 Abstract A new fixed-point charge potential model for water has been developed, targeting the accurate prediction of the vapor-liquid coexistence properties over a broad temperature range. The model

  20. An improved genetic algorithm based on J1 triangulation and fixed point theory

    Microsoft Academic Search

    Jingjun Zhang; Yanmin Shang; Ruizhen Gao; Yuzhen Dong

    2009-01-01

    An improved genetic algorithm based on J1 triangulation is proposed for multimodal optimization problems. And the fixed point theory is introduced into this improved algorithm. The optimal problems are conversed to fixed point problems. In this paper, several typical functions are used to demonstrate the effectiveness of this algorithm, and the testing results show that the improved genetic algorithm is

  1. THE LEFSCHETZ FIXED POINT THEORY FOR MORPHISMS IN TOPOLOGICAL VECTOR SPACES

    Microsoft Academic Search

    Lech Górniewicz; Danuta Rozpoch-Nowakowska

    The Lefschetz Fixed Point Theorem for compact absorbing contraction morphisms (CAC-morphisms) of retracts of open subsets in admissible spaces in the sense of Klee is proved. Moreover, the relative version of the Lefschetz Fixed Point Theorem and the Lefschetz Periodic Theorem are considered. Additionally, a full classification of morphisms with compact attractors in the non-metric case is obtained.

  2. The resolution of field identification fixed points in diagonal coset theories

    Microsoft Academic Search

    Jürgen Fuchs; Bert Schellekens; Christoph Schweigert

    1996-01-01

    The fixed point resolution problem is solved for diagonal coset theories. The primary fields into which the fixed points are resolved are described by submodules of the branching spaces, obtained as eigenspaces of the automorphisms that implement field identification. To compute the characters and the modular S-matrix we use ‘orbit Lie algebras’ and ‘twining characters’, which were introduced in a

  3. 24 CFR 50.16 - Decision points for policy actions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY General Policy: Decision Points § 50.16 Decision points for policy actions....

  4. 24 CFR 50.16 - Decision points for policy actions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY General Policy: Decision Points § 50.16 Decision points for policy actions....

  5. 24 CFR 50.16 - Decision points for policy actions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY General Policy: Decision Points § 50.16 Decision points for policy actions....

  6. 24 CFR 50.16 - Decision points for policy actions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY General Policy: Decision Points § 50.16 Decision points for policy actions....

  7. 24 CFR 50.16 - Decision points for policy actions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY General Policy: Decision Points § 50.16 Decision points for policy actions....

  8. Triple point of e-deuterium as an accurate thermometric fixed point

    SciTech Connect

    Pavese, F.; McConville, G.T.

    1986-01-01

    The triple point of deuterium (18.7/sup 0/K) is the only possibility for excluding vapor pressure measurements in the definition of a temperature scale based on fixed points between 13.81 and 24.562/sup 0/K. This paper reports an investigation made at the Istituto di Metrologia and Mound Laboratory, using extremely pure deuterium directly sealed at the production plant into small metal cells. The large contamination by HD of commercially available gas, that cannot be accounted and corrected for due to its increase in handling, was found to be very stable with time after sealing in IMGC cells. HD contamination can be limited to less than 100 ppM in Monsanto cells, both with n-D/sub 2/ and e-D/sub 2/, when filled directly from the thermal diffusion column and sealed at the factory. e-D/sub 2/ requires a special deuterated catalyst. The triple point temperature of e-D/sub 2/ has been determined to be: T(NPL-IPTS-68) = 18.7011 +- 0.002/sup 0/K. 20 refs., 3 figs., 2 tabs.

  9. Least Fixed Points in Modal Logic1 Sergej Mardaev

    E-print Network

    Mardaev, Sergey

    ::: qn) de nes the least xed point P if P = !(Q1 ::: Qn) holds. A formula !(q1 ::: qn) preserves, there is a formula !(q1 ::: qn) which de nes the unique xed point of the operator F' in each strictly partially

  10. A New Co-C Eutectic Fixed-Point Cell for Thermocouple Calibration at

    NASA Astrophysics Data System (ADS)

    Failleau, G.; Deuzé, T.; Jouin, D.; Mokdad, S.; Briaudeau, S.; Sadli, M.

    2014-07-01

    The eutectic Co-C is a promising system to serve as a thermometric fixed point beyond the freezing point of copper (). Some national metrology institutes have developed, characterized, and compared their Co-C fixed-point cells based on conventional designs. Indeed, the fixed-point cells constructed are directly inspired by the technologies applied to the fixed points of the ITS-90 to the lower levels of temperature. By studying the eutectic metal-carbon systems, is appears that the high temperatures of implementation give a set of difficulties, such as the strong mechanical stresses on the graphite crucibles, due to the important thermal expansion of the eutectic alloys during their phase transitions. If these devices are suitable with research activities to serve like primary standards, it is not envisaged to propose them for a direct application to the calibration activities for the industry. As regards the limited robustness of the conventional fixed-point cells constructed, an intensive use of these device would not be reasonable, in term of cost for example. In this paper, a new Co-C fixed-point design is introduced. This low cost device has been developed specifically for intensive use in thermocouple calibration activities, with the aim of achieving the lowest level of uncertainties as is practicable. Thus, in this paper, the metrological characterization of this device is also presented, and a direct comparison to a primary Co-C fixed-point cell previously constructed is discussed.

  11. Renormalization-group study of the fixed points and of their stability for phase transitions with four-component order parameters

    NASA Astrophysics Data System (ADS)

    Toledano, Jean-Claude; Michel, Louis; Toledano, Pierre; Brezin, Edouard

    1985-06-01

    The renormalization-group recursion relations are solved for the effective Hamiltonians relative to phase transitions with four-component order parameters. For this value of n there are 22 types of Hamiltonians which can be classified into two categories according to the action of their normalizer GN on the corresponding parameter space (GN is the symmetry group leaving globally invariant this space). In the first case, GN generates a finite number of isolated fixed points whose characteristics can be deduced from the detailed investigation of five Hamiltonians only. In the second category, for which GN is a continuous group, there are, in addition to isolated fixed points, continuous manifolds of physically equivalent fixed points (the dimension of the manifolds is either one or three). In the search for a stable fixed point, the continuous manifolds can be ignored, while the isolated points are related to the five former Hamiltonians. For n=4, it is necessary to solve the recursion relations to two-loop order. The only possible stable ones among the fixed points then arise from a splitting of points which coincide, to one-loop order, with the isotropic fixed point. Extending, to two-loop order, a result recently established to the preceding order, we show that if a stable fixed point exists, it is unique. For n=4, the stable fixed point has one of three possible symmetries : di-icosahedral, hypercubic, or dicylindrical. Despite this anisotropy of the critical fluctuations, the exponents associated with any of the stable fixed points are identical to order ?2 to the ``isotropic'' exponents corresponding to n=4. The cubic point is destabilized by any operator of symmetry lower than cubic. The dicylindrical one remains stable with respect to certain anisotropies of lower symmetry. We examine the available experimental data in light of the preceding theoretical results concerning the critical behavior and the thermodynamic order of the transitions. On the other hand, we establish two general symmetry conditions relative to the stable fixed points determined by the renormalization-group equations. The first one specifies group theoretically, for each value of n, the possible symmetries G*i of the stable fixed points. The second one formulates a necessary condition for the occurrence of an anisotropic stable fixed point: The normalizer GN of the considered parameter space must fulfill the condition GN?@BG*i for one, at least, of the former G*i groups. These rules are shown to be very restrictive for n=4: On the basis of symmetry the lack of a stable fixed point can be asserted for 10 Hamiltonians out of 22, without solving the fixed-point equations.

  12. Common fixed points in best approximation for Banach operator pairs with Ciric type I-contractions

    NASA Astrophysics Data System (ADS)

    Hussain, N.

    2008-02-01

    The common fixed point theorems, similar to those of Ciric [Lj.B. Ciric, On a common fixed point theorem of a Gregus type, Publ. Inst. Math. (Beograd) (N.S.) 49 (1991) 174-178; Lj.B. Ciric, On Diviccaro, Fisher and Sessa open questions, Arch. Math. (Brno) 29 (1993) 145-152; Lj.B. Ciric, On a generalization of Gregus fixed point theorem, Czechoslovak Math. J. 50 (2000) 449-458], Fisher and Sessa [B. Fisher, S. Sessa, On a fixed point theorem of Gregus, Internat. J. Math. Math. Sci. 9 (1986) 23-28], Jungck [G. Jungck, On a fixed point theorem of Fisher and Sessa, Internat. J. Math. Math. Sci. 13 (1990) 497-500] and Mukherjee and Verma [R.N. Mukherjee, V. Verma, A note on fixed point theorem of Gregus, Math. Japon. 33 (1988) 745-749], are proved for a Banach operator pair. As applications, common fixed point and approximation results for Banach operator pair satisfying Ciric type contractive conditions are obtained without the assumption of linearity or affinity of either T or I. Our results unify and generalize various known results to a more general class of noncommuting mappings.

  13. G-CO Fixed points of rigid motions

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A rigid motion of the plane is a map of the plane to itself which preserves distances between points. Let $f$ be such a function.A point $x$ in the pla...

  14. Computable counter-examples to the Brouwer fixed-point theorem

    E-print Network

    Petrus H. Potgieter

    2008-04-21

    This paper is an overview of results that show the Brouwer fixed-point theorem (BFPT) to be essentially non-constructive and non-computable. The main results, the counter-examples of Orevkov and Baigger, imply that there is no procedure for finding the fixed point in general by giving an example of a computable function which does not fix any computable point. Research in reverse mathematics has shown the BFPT to be equivalent to the weak K\\"onig lemma in RCA$_0$ (the system of recursive comprehension) and this result is illustrated by relating the weak K\\"onig lemma directly to the Baigger example.

  15. Math 512: Finite Model Theory Ptime = Fixed point axiomatizable

    E-print Network

    Baldwin, John T.

    is by induction on complexity of formulas. The_* *key point_ is that to decide [LF P __xXOE(__x, S)]__a, knowing by induction that_for any b* *, OE(b, S) can be decided in polynomial time. So step 0 setting S = ;, check is decided in PTIME we mean there is a deterministic Turing machine M s* *uch that for some k: 1. M

  16. Mean square asymptotic stability of stochastic delayed systems by fixed point theory

    Microsoft Academic Search

    Bi-Rong Zhao; Fei-Qi Deng; Jiao-Wan Luo

    2009-01-01

    In this paper, we consider a nonlinear neutral stochastic system with variable delays and give conditions to ensure that the zero solution is asymptotically mean square stable by means of fixed point theory. These conditions do not require the roundedness of delays, nor do they ask for a fixed sign on the coefficient functions. An asymptotically mean square stable theorem

  17. Fixed points, periodic points, and coin-tossing sequences for mappings defined on two-dimensional cells

    Microsoft Academic Search

    Duccio Papini; Fabio Zanolin

    2004-01-01

    We propose, in the general setting of topological spaces, a definition of two-dimensional oriented cell and consider maps which possess a property of stretching along the paths with respect to oriented cells. For these maps, we prove some theorems on the existence of fixed points, periodic points, and sequences of iterates which are chaotic in a suit- able manner. Our

  18. The Proof-Theoretic Analysis of Transfinitely Iterated Fixed Point Theories

    Microsoft Academic Search

    Gerhard Jäger; Reinhard Kahle; Anton Setzer; Thomas Strahm

    1999-01-01

    This article provides the proof-theoretic analysis of the transfinitely iterated fixed point theories $\\\\widehat{ID}_\\\\alpha and \\\\widehat{ID}_{<\\\\alpha};$ the exact proof-theoretic ordinals of these systems are presented.

  19. Common Fixed Point Theory for Multivalued Contractive Maps of Reich Type in Uniform Spaces

    Microsoft Academic Search

    Ravi P. Agarwal; Donal ORegan; Nikalaos S. Papageorgiou

    2004-01-01

    This article presents common fixed point theory for multivalued maps defined on complete gauge spaces. Our analysis is elementary and relies only on properties of the generalized Hausdorff pseudometric.

  20. Kondo effect in a Luttinger liquid: a two-channel Kondo fixed point is not possible

    NASA Astrophysics Data System (ADS)

    Le Hur, Karyn

    1999-01-01

    The fixed point of the two-channel Kondo (TCK) model does not respect the vacuum of the backward Kondo scattering exchange. It proves rigorously that such a solution for the Kondo effect in a Luttinger liquid is forbidden while backscattering effects are prominent. When U?0, a description of the fixed point in terms of a local Fermi-liquid is not completely satisfactory since the Wilson ratio is not universal.

  1. A Fixed Point Theory for Quasi-Contractive Mappings in Ordered Sets

    Microsoft Academic Search

    Jiawei Chen; Zhongping Wan; Zhanyi Ao; Liuyang Yuan

    \\u000a In this paper, the author presents a fixed point theorem for quasicontractive maps in partially ordered sets, which extends\\u000a corresponding results of [Nieto, J. J. and Rodriguez-Lopez, R.: Contractive Mapping Theorems in Partially Ordered Sets and\\u000a Applicationsto Ordinary Differential Equations. Order, 22(2005), 223-239; Nieto, J. J. and Rodriguez-Lopez, R.: Existence\\u000a and Uniqueness of Fixed Point in Partially Ordered Sets and

  2. Fixed-point smoothing for linear discrete-time systems with multiple delayed measurements

    Microsoft Academic Search

    Hongguo Zhao; Xiaochun Guo; Peng Cui

    2010-01-01

    This paper investigates the fixed-point smoothing problems for linear time-delay systems. The linear systems have l + 1 output channels. One is instantaneous observation and the others are delayed. The fixed-point smoothers involving recursive algorithm and non-recursive algorithm are designed by using reorganized innovation analysis approach without relying on the system augmentation. It is further shown that the deign of

  3. Remarks on a fixed point theorem of Caristi 

    E-print Network

    Egle, David Lee

    1977-01-01

    , &) is a partially ordered set. Let x c X. Define a set M by A = lA : A C X, x c A, and A is totally ordered&. Order M by set inclusion; that is, A Q B iff A C B. Let ( g, 6 ) be a chain in Af, and let B= UA Ac (g, g) Clearly, x c B and 8 L: X. Let a... point. Finally, it is shown that Theorem 1. 2 implies Theorem 1. 1 and hence is a generalization of Theorem 1. 1. Proof of Theorem 1. 1: Define the function q: X ~ R by + -r d(x, f(x)), if r & -1 4)t(x) = -I/r d(x, f(x)), if -1 & r & 0 Since...

  4. Motion Capture of Hands in Action using Discriminative Salient Points

    E-print Network

    Kersting, Kristian

    Motion Capture of Hands in Action using Discriminative Salient Points Luca Ballan1 , Aparna Taneja1 constraints, as in [6], to avoid hand intersections. #12;2 L. Ballan, A. Taneja, J. Gall, L. Van Gool, and M

  5. Extending the Nonlinear-Beam-Dynamics Concept of 1D Fixed Points to 2D Fixed Lines

    NASA Astrophysics Data System (ADS)

    Franchetti, G.; Schmidt, F.

    2015-06-01

    The origin of nonlinear dynamics traces back to the study of the dynamics of planets with the seminal work of Poincaré at the end of the nineteenth century: Les Méthodes Nouvelles de la Mécanique Céleste, Vols. 1-3 (Gauthier Villars, Paris, 1899). In his work he introduced a methodology fruitful for investigating the dynamical properties of complex systems, which led to the so-called "Poincaré surface of section," which allows one to capture the global dynamical properties of a system, characterized by fixed points and separatrices with respect to regular and chaotic motion. For two-dimensional phase space (one degree of freedom) this approach has been extremely useful and applied to particle accelerators for controlling their beam dynamics as of the second half of the twentieth century. We describe here an extension of the concept of 1D fixed points to fixed lines in two dimensions. These structures become the fundamental entities for characterizing the nonlinear motion in the four-dimensional phase space (two degrees of freedom).

  6. Extending the Nonlinear-Beam-Dynamics Concept of 1D Fixed Points to 2D Fixed Lines.

    PubMed

    Franchetti, G; Schmidt, F

    2015-06-12

    The origin of nonlinear dynamics traces back to the study of the dynamics of planets with the seminal work of Poincaré at the end of the nineteenth century: Les Méthodes Nouvelles de la Mécanique Céleste, Vols. 1-3 (Gauthier Villars, Paris, 1899). In his work he introduced a methodology fruitful for investigating the dynamical properties of complex systems, which led to the so-called "Poincaré surface of section," which allows one to capture the global dynamical properties of a system, characterized by fixed points and separatrices with respect to regular and chaotic motion. For two-dimensional phase space (one degree of freedom) this approach has been extremely useful and applied to particle accelerators for controlling their beam dynamics as of the second half of the twentieth century. We describe here an extension of the concept of 1D fixed points to fixed lines in two dimensions. These structures become the fundamental entities for characterizing the nonlinear motion in the four-dimensional phase space (two degrees of freedom). PMID:26196806

  7. Fixed point sensitivity analysis of interacting structured populations.

    PubMed

    Barabás, György; Meszéna, Géza; Ostling, Annette

    2014-03-01

    Sensitivity analysis of structured populations is a useful tool in population ecology. Historically, methodological development of sensitivity analysis has focused on the sensitivity of eigenvalues in linear matrix models, and on single populations. More recently there have been extensions to the sensitivity of nonlinear models, and to communities of interacting populations. Here we derive a fully general mathematical expression for the sensitivity of equilibrium abundances in communities of interacting structured populations. Our method yields the response of an arbitrary function of the stage class abundances to perturbations of any model parameters. As a demonstration, we apply this sensitivity analysis to a two-species model of ontogenetic niche shift where each species has two stage classes, juveniles and adults. In the context of this model, we demonstrate that our theory is quite robust to violating two of its technical assumptions: the assumption that the community is at a point equilibrium and the assumption of infinitesimally small parameter perturbations. Our results on the sensitivity of a community are also interpreted in a niche theoretical context: we determine how the niche of a structured population is composed of the niches of the individual states, and how the sensitivity of the community depends on niche segregation. PMID:24368160

  8. FIXED POINT THEORY AND THE K--THEORETIC TRACE Ross Geoghegan \\Lambda and Andrew Nicas \\Lambda\\Lambda

    E-print Network

    Geoghegan, Ross

    FIXED POINT THEORY AND THE K--THEORETIC TRACE Ross Geoghegan \\Lambda and Andrew Nicas \\Lambda\\Lambda August 27, 1996 Abstract. The relationship between fixed point theory and K --theory is explained, both classical Nielsen theory (versus K0 ) and 1--parameter fixed point theory (versus K1 ). In particular

  9. Fixed-points theory for global vibration control using vibration neutralizer

    Microsoft Academic Search

    Jedol Dayou

    2006-01-01

    The vibration neutralizer has been used in many applications since invented. In many cases, an ingenious design law called fixed-points theory was utilized in determining the optimum tuning and damping ratios of the device. However, those applications are limited to point response control of a relatively simple structure. There are some applications related to continuous structures but the purpose is

  10. Nonquadratic gauge fixing and global gauge invariance in the effective action

    SciTech Connect

    Brandt, F. T. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, Sao Paulo 05315-970 (Brazil); McKeon, D. G. C. [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada)

    2009-04-15

    The possibility of having a gauge fixing term in the effective Lagrangian that is not a quadratic expression has been explored in spin-two theories so as to have a propagator that is both traceless and transverse. We first show how this same approach can be used in spontaneously broken gauge theories as an alternate to the 't Hooft gauge fixing which avoids terms quadratic in the scalar fields. This 'nonquadratic' gauge fixing in the effective action results in two complex fermionic and one real bosonic ghost field. A global gauge invariance involving a fermionic gauge parameter, analogous to the usual Becchi-Rouet-Stora-Tyutin invariance, is present in this effective action.

  11. Infrared fixed point in SU(2) gauge theory with adjoint fermions

    SciTech Connect

    DeGrand, Thomas; Shamir, Yigal; Svetitsky, Benjamin [Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel)

    2011-04-01

    We apply Schroedinger-functional techniques to the SU(2) lattice gauge theory with N{sub f}=2 flavors of fermions in the adjoint representation. Our use of hypercubic smearing enables us to work at stronger couplings than did previous studies, before encountering a critical point and a bulk phase boundary. Measurement of the running coupling constant gives evidence of an infrared fixed point g{sub *} where 1/g{sub *}{sup 2}=0.20(4)(3). At the fixed point, we find a mass anomalous dimension {gamma}{sub m}(g{sub *})=0.31(6).

  12. Reference in Action: Links between Pointing and Language

    ERIC Educational Resources Information Center

    Cooperrider, Kensy Andrew

    2011-01-01

    When referring to things in the world, speakers produce utterances that are composites of speech and action. Pointing gestures are a pervasive part of such composite utterances, but many questions remain about exactly how pointing is integrated with speech. In this dissertation I present three strands of research that investigate relations of…

  13. Fixed-point bifurcation analysis in biological models using interval polynomials theory.

    PubMed

    Rigatos, Gerasimos G

    2014-06-01

    The paper proposes a systematic method for fixed-point bifurcation analysis in circadian cells and similar biological models using interval polynomials theory. The stages for performing fixed-point bifurcation analysis in such biological systems comprise (i) the computation of fixed points as functions of the bifurcation parameter and (ii) the evaluation of the type of stability for each fixed point through the computation of the eigenvalues of the Jacobian matrix that is associated with the system's nonlinear dynamics model. Stage (ii) requires the computation of the roots of the characteristic polynomial of the Jacobian matrix. This problem is nontrivial since the coefficients of the characteristic polynomial are functions of the bifurcation parameter and the latter varies within intervals. To obtain a clear view about the values of the roots of the characteristic polynomial and about the stability features they provide to the system, the use of interval polynomials theory and particularly of Kharitonov's stability theorem is proposed. In this approach, the study of the stability of a characteristic polynomial with coefficients that vary in intervals is equivalent to the study of the stability of four polynomials with crisp coefficients computed from the boundaries of the aforementioned intervals. The efficiency of the proposed approach for the analysis of fixed-point bifurcations in nonlinear models of biological neurons is tested through numerical and simulation experiments. PMID:24817437

  14. One-parameter semigroups of analytic functions, fixed points and the Koenigs function

    SciTech Connect

    Goryainov, Victor V; Kudryavtseva, Olga S [Volzhsky Institute of Humanities, Volgograd Region, Volzhsky (Russian Federation)

    2011-07-31

    Analogues of the Berkson-Porta formula for the infinitesimal generator of a one-parameter semigroup of holomorphic maps of the unit disc into itself are obtained in the case when, along with a Denjoy-Wolff point, there also exist other fixed points. With each one-parameter semigroup a so-called Koenigs function is associated, which is a solution, common for all elements of the one-parameter semigroup, of a certain functional equation (Schroeder's equation in the case of an interior Denjoy-Wolff point and Abel's equation in the case of a boundary Denjoy-Wolff point). A parametric representation for classes of Koenigs functions that takes account of the Denjoy-Wolff point and other fixed points of the maps in the one-parameter semigroup is presented. Bibliography: 19 titles.

  15. Fixed-point theorems for families of weakly non-expansive maps

    NASA Astrophysics Data System (ADS)

    Mai, Jie-Hua; Liu, Xin-He

    2007-10-01

    In this paper, we present some fixed-point theorems for families of weakly non-expansive maps under some relatively weaker and more general conditions. Our results generalize and improve several results due to Jungck [G. Jungck, Fixed points via a generalized local commutativity, Int. J. Math. Math. Sci. 25 (8) (2001) 497-507], Jachymski [J. Jachymski, A generalization of the theorem by Rhoades and Watson for contractive type mappings, Math. Japon. 38 (6) (1993) 1095-1102], Guo [C. Guo, An extension of fixed point theorem of Krasnoselski, Chinese J. Math. (P.O.C.) 21 (1) (1993) 13-20], Rhoades [B.E. Rhoades, A comparison of various definitions of contractive mappings, Trans. Amer. Math. Soc. 226 (1977) 257-290], and others.

  16. Infrared fixed point solution for the top quark mass and unification of couplings in the MSSM

    SciTech Connect

    Bardeen, W.A. [Superconducting Super Collider Lab., Dallas, TX (United States); Carena, M.; Pokorski, S.; Wagner, C.E.M. [Max-Planck-Institut fuer Physik, Muenchen (Germany). Werner-Heisenberg-Institut

    1993-08-01

    We analyze the implications of the infrared quasi fixed point solution for the top quark mass in the Minimal Supersymmetric Standard Model. This solution could explain in a natural way the relatively large value of the top quark mass and, if confirmed experimentally, may be suggestive of the onset of nonperturbative physics at very high energy scales. In the framework of grand unification, the expected bottom quark -- tau lepton Yukawa coupling unification is very sensitive to the fixed point structure of the top quark mass. For the presently allowed values of the electroweak parameters and the bottom quark mass, the Yukawa coupling unification implies that the top quark mass must be within ten percent of its fixed point values.

  17. Clarification of Uncertainty in the Triple Point of Water as a Temperature Fixed Point

    Microsoft Academic Search

    Yoshizo Suyama

    1980-01-01

    The triple point of water in sealed glass cells with commonly recommended specifications possesses incomprehensible characteristics, namely a gradual rise of the triple point temperature by about 0.2 mK during the first few days and, in some cells, a gradual depression after the first ten or so hours. This is a source of uncertainty in the triple point of water

  18. A least-squares fixed-point iterative algorithm for multiple illumination photoacoustic tomography

    PubMed Central

    Harrison, Tyler; Shao, Peng; Zemp, Roger J.

    2013-01-01

    The optical absorption of tissues provides important information for clinical and pre-clinical studies. The challenge in recovering optical absorption from photoacoustic images is that the measured pressure depends on absorption and local fluence. One reconstruction approach uses a fixed-point iterative technique based on minimizing the mean-squared error combined with modeling of the light source to determine optical absorption. With this technique, convergence is not guaranteed even with an accurate measure of optical scattering. In this work we demonstrate using simulations that a new multiple illumination least squares fixed-point iteration algorithm improves convergence - even with poor estimates of optical scattering. PMID:24156078

  19. Non-perturbative fixed points and renormalization group improved effective potential

    NASA Astrophysics Data System (ADS)

    Dias, A. G.; Gomez, J. D.; Natale, A. A.; Quinto, A. G.; Ferrari, A. F.

    2014-12-01

    The stability conditions of a renormalization group improved effective potential have been discussed in the case of scalar QED and QCD with a colorless scalar. We calculate the same potential in these models assuming the existence of non-perturbative fixed points associated with a conformal phase. In the case of scalar QED the barrier of instability found previously is barely displaced as we approach the fixed point, and in the case of QCD with a colorless scalar not only the barrier is changed but the local minimum of the potential is also changed.

  20. High-Density Fixed Point for Radially Compressed Single-Component Plasmas

    SciTech Connect

    Danielson, J. R.; Surko, C. M.; O'Neil, T. M. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

    2007-09-28

    Rotating electric fields are used to compress electron plasmas confined in a Penning-Malmberg trap. Bifurcation and hysteresis are observed between low-density and high-density steady states as a function of the applied electric field amplitude and frequency. These observations are explained in terms of torque-balanced fixed points using a simple model of the torques on the plasma. Perturbation experiments near the high-density fixed point are used to determine the magnitude, frequency, and voltage dependence of the drive torque. The broader implications of these results are discussed.

  1. Parallel fixed point implementation of a radial basis function network in an FPGA.

    PubMed

    de Souza, Alisson C D; Fernandes, Marcelo A C

    2014-01-01

    This paper proposes a parallel fixed point radial basis function (RBF) artificial neural network (ANN), implemented in a field programmable gate array (FPGA) trained online with a least mean square (LMS) algorithm. The processing time and occupied area were analyzed for various fixed point formats. The problems of precision of the ANN response for nonlinear classification using the XOR gate and interpolation using the sine function were also analyzed in a hardware implementation. The entire project was developed using the System Generator platform (Xilinx), with a Virtex-6 xc6vcx240t-1ff1156 as the target FPGA. PMID:25268918

  2. Non-Gaussian fixed point in four-dimensional pure compact U(1) gauge theory on the lattice

    E-print Network

    J. Jersak; C. B. Lang; T. Neuhaus

    1996-06-21

    The line of phase transitions, separating the confinement and the Coulomb phases in the four-dimensional pure compact U(1) gauge theory with extended Wilson action, is reconsidered. We present new numerical evidence that a part of this line, including the original Wilson action, is of second order. By means of a high precision simulation on homogeneous lattices on a sphere we find that along this line the scaling behavior is determined by one fixed point with distinctly non-Gaussian critical exponent nu = 0.365(8). This makes the existence of a nontrivial and nonasymptotically free four-dimensional pure U(1) gauge theory in the continuum very probable. The universality and duality arguments suggest that this conclusion holds also for the monopole loop gas, for the noncompact abelian Higgs model at large negative squared bare mass, and for the corresponding effective string theory.

  3. Performance simulation of a fixed-point rake receiver on CDMA2000 1X reverse link

    NASA Astrophysics Data System (ADS)

    Zhao, Junhui; Zhao, Chunming; You, XiaoHu

    2001-10-01

    The majority of the performance analysis of rake receiver presented in the cdma2000-1x has assumed the use of floating point arithmetic. However, if fixed-point arithmetic is employed, a corresponding degradation in the BER performance of the rake receiver is expected. In this paper, we present the performance degradation due to the finite word length implementation of the rake receiver with various A/D quantizers for a cdma2000-1x base station. The 4-bit, 6-bit and 8-bit resolution A/DS are used in some simulation runs to compare their impact on performance, 4-bit viterbi decoder is used in all the fixed-point simulations. It is show that, with proper design, the BER(Bit Error Ration) performance with 8-bit A/D seems sufficiently close to that of the floating point implementation.

  4. Automatic Accuracy-Guaranteed Bit-Width Optimization for Fixed and Floating-Point Systems

    Microsoft Academic Search

    W. G. Osborne; Ray C. C. Cheung; José Gabriel F. Coutinho; Wayne Luk; Oskar Mencer

    2007-01-01

    In this paper we present Minibit+, an approach that opti- mizes the bit-widths of fixed-point and floating-point de- signs, while guaranteeing accuracy. Our approach adopts different levels of analysis giving the designer the opportu- nity to terminate it at any stage to obtain a result. Range analysis is achieved using a combined affine and interval arithmetic approach to reduce the

  5. Reflections on Quantum Computing Quantum Computing Based on Fixed Point Dynamics

    E-print Network

    Svozil, Karl

    Reflections on Quantum Computing Quantum Computing Based on Fixed Point Dynamics WHEN ARE QUANTUM SPEEDUPS POSSIBLE? T his section discusses the possibility that speedups in quantum computing can the computational complexity class UP [2]. Typical examples are Shor's quantum algorithm for prime factoring [3

  6. A Buchholz rule for modal fixed point logics Gerhard Jager and Thomas Studer

    E-print Network

    Jäger, Gerhard

    A Buchholz rule for modal fixed point logics Gerhard J¨ager and Thomas Studer Abstract. Buchholz section we prove a cut elimination and collapsing result similar to that of Buchholz [3]. Mathematics, Buchholz rule. 1. Introduction Buchholz's µ+1-rules play a prominent role in the proof-theoretic analysis

  7. Fixed point theorems in the Arnol'd model about instability of the actionvariables in phasespace

    E-print Network

    ' 2 +cos t)) I 2 R 2 (``Arnol'd model about diffusion''); by means of fixed point theorems tools suggested by Arnol'd i.e. the contraction mapping method togheter with the ``conical metric theorem (``Arnol'd diffusion'') is stated Assume 0 ! A ! B: For any '' ? 0 there exists a ¯ o (''; A; B

  8. THE LEFSCHETZ FIXED POINT THEOREM AND SOLUTIONS TO POLYNOMIALS OVER FINITE FIELDS

    E-print Network

    May, J. Peter

    the Betti numbers in Example 2.24. Example 1.5. We use an open-source mathematical software called SageTHE LEFSCHETZ FIXED POINT THEOREM AND SOLUTIONS TO POLYNOMIALS OVER FINITE FIELDS ANG LI Contents 1 solutions over a finite field. If we consider the solutions over C, the set of solutions is a complex

  9. FastISA: A fast fixed-point algorithm for Independent Subspace Analysis

    E-print Network

    Hyvärinen, Aapo

    FastISA: A fast fixed-point algorithm for Independent Subspace Analysis Aapo Hyv¨arinen and Urs K¨oster x)2 )1/2 (1) Urs K¨oster is supported by a scholarship from the Alfried Krupp von Bohlen und Halbach

  10. Quaternary Voltage-Mode Logic Cells and Fixed-Point Multiplication Circuits*

    E-print Network

    Thornton, Mitchell

    in that higher density per integrated circuit area can be achieved as compared to binary logic implementationsQuaternary Voltage-Mode Logic Cells and Fixed-Point Multiplication Circuits* Satyendra R of logic circuits is based on Field Effect Transistors (FETs) that have different voltage threshold levels

  11. 3D transient fixed point mesh adaptation for time-dependent problems: Application to CFD simulations

    E-print Network

    Frey, Pascal

    , in general, the classical mesh adaptation algorithm reveals intrinsically inadequate when dealing with CFDAuthor's personal copy 3D transient fixed point mesh adaptation for time-dependent problems of unstructured meshes in three dimensions for transient problems with an empha- sis on CFD simulations

  12. 3D transient fixed point mesh adaptation for time-dependent problems: Application to CFD simulations

    E-print Network

    Alauzet, Frédéric

    3D transient fixed point mesh adaptation for time-dependent problems: Application to CFD dimensions for transient problems with an empha- sis on CFD simulations. The classical mesh adaptation scheme mesh adaptation algorithm reveals intrinsically inadequate when dealing with CFD transient simulations

  13. Viscosity approximation methods for equilibrium problems and fixed point problems in Hilbert spaces

    Microsoft Academic Search

    Satoru Takahashi; Wataru Takahashi

    2007-01-01

    In this paper, we introduce an iterative scheme by the viscosity approximation method for finding a common element of the set of solutions of an equilibrium problem and the set of fixed points of a nonexpansive mapping in a Hilbert space. Then, we prove a strong convergence theorem which is connected with Combettes and Hirstoaga's result [P.L. Combettes, S.A. Hirstoaga,

  14. Fixed Point Library Based on ISO\\/IEC Standard DTR 18037 for Atmel AVR Microcontrollers

    Microsoft Academic Search

    Wilfried Elmenreich; Maximilian Rosenblattl; Andreas Wolf

    2007-01-01

    The ISO\\/IEC Standard DTR 18037 defines the syntax and semantics for fixed point operations for programming embedded hardware in C. However, there are currently only few compilers available that support this standard. Therefore, we have implemented a stand-alone library according to the standard that can be compiled with standard C compilers. The library is available as open source and written

  15. Crustal deformation measurements in Central Japan determined by a global positioning system fixed-point network

    Microsoft Academic Search

    Seiichi Shimada; Yehuda Bock

    1992-01-01

    A Global Positioning System (GPS) fixed-point network has been operating in the Kanto and Tokai districts of central Japan since April 1988 to detect crustal deformation associated with the convergence of the Eurasian. Pacific, North American, and Philippine Sea plates and to monitor the deformation cycles of frequent large interplate and intraplate earthquakes. This 10-station network established by the National

  16. FEASIBILITY OF FIXED-POINT TRANSVERSAL ADAPTIVE FILTERS IN FPGA DEVICES WITH EMBEDDED DSP BLOCKS

    E-print Network

    Slatton, Clint

    FEASIBILITY OF FIXED-POINT TRANSVERSAL ADAPTIVE FILTERS IN FPGA DEVICES WITH EMBEDDED DSP BLOCKS adaptive filters for digital signal processing have traditionally been implemented into DSP processors due as incorporating the embedded DSP block, the FPGA devices have become a serious contender in the signal processing

  17. Comments on lattice gauge theories with infrared-attractive fixed points

    E-print Network

    Thomas DeGrand; Anna Hasenfratz

    2009-08-17

    Theories of interacting gauge fields and fermions can possess a running gauge coupling with an infrared attractive fixed point (IRFP). We present a minimal description of the physics of these systems and comment on some simple expectations for results from lattice simulations done within the basin of attraction of the IRFP in these theories.

  18. Total stability of a class of hybrid dynamic systems based on fixed point theory

    Microsoft Academic Search

    M. De la Sen

    2010-01-01

    Elementary stability results with robustness prametric issues are obtained for a class of nominally linear hybrid systems through total stability theorems based on fixed point theory. The class of hybrid systems is that of coupled continuous-time and digital systems subject to state perturbations whose nominal (i.e. unperturbed) parts are linear and, in general, time-varying.

  19. Axioms for a local Reidemeister trace in fixed point and coincidence theory on differentiable manifolds

    Microsoft Academic Search

    P. Christopher Staecker

    2009-01-01

    .  We give axioms which characterize the local Reidemeister trace for orientable differentiable manifolds. The local Reidemeister\\u000a trace in fixed point theory is already known, and we provide both uniqueness and existence results for the local Reidemeister\\u000a trace in coincidence theory.

  20. Some properties of the characteristic of convexity relating to fixed point theory

    Microsoft Academic Search

    DAVID J. DOWNING; BARRY TURETT

    1983-01-01

    Fixed point theorems for uniformly lipschitzian mappings often restrict the characteristic of convexity, ?o(X), of the underlying Banach space to be less than one. This condition is discussed; in particular, it is shown that, for Banach spaces, ?o(x) < 1 is equivalent to a condition imposed by E. A. Lif schitz in arbitrary metric spaces. The stability of this condition

  1. Scalar-tensor cosmologies: Fixed points of the Jordan frame scalar field

    SciTech Connect

    Jaerv, Laur; Kuusk, Piret; Saal, Margus [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Tartu Observatory, Toravere 61602 (Estonia)

    2008-10-15

    We study the evolution of homogeneous and isotropic, flat cosmological models within the general scalar-tensor theory of gravity with arbitrary coupling function and potential. After introducing the limit of general relativity we describe the details of the phase space geometry. Using the methods of dynamical systems for the decoupled equation of the Jordan frame scalar field we find the fixed points of flows in two cases: potential domination and matter domination. We present the conditions on the mathematical form of the coupling function and potential which determine the nature of the fixed points (attractor or other). There are two types of fixed points, both are characterized by cosmological evolution mimicking general relativity, but only one of the types is compatible with the Solar System parametrized post-Newtonian (PPN) constraints. The phase space structure should also carry over to the Einstein frame as long as the transformation between the frames is regular which however is not the case for the latter (PPN compatible) fixed point.

  2. Fixed point theory for a new type of contractive multivalued operators

    Microsoft Academic Search

    Ghiocel Mo?; Adrian Petru?el

    2009-01-01

    The aim of this paper is to discuss some basic problems (data dependence, well-posedness, nonself operators, homotopy results, generalized contractions) of the fixed point theory for a new type contractive multivalued operator. The results complement and extend some very recent results proved by M. Kikkawa and T. Suzuki, as well as, other theorems given by M. Frigon and A. Granas,

  3. One parameter fixed point theory and gradient flows of closed 1-forms

    Microsoft Academic Search

    D. Schuetz

    2001-01-01

    We use the one parameter fixed point theory of Geoghegan and Nicas to get information about the closed orbit structure of transverse gradient flows of closed 1-forms on a closed manifold M. We define a noncommutative zeta function in an object related to the first Hochschild homology group of the Novikov ring associated to the 1-form and relate it to

  4. Application of Fixed Point Theory to Uncertain Nonlinear and MIMO Feedback Problems

    Microsoft Academic Search

    Isaac Horowitz

    1990-01-01

    The essence of fixed point theory in feedback design is to replace the difficult parts of the design problem by others involving either uncertain linear time invariant (LTI) elements and\\/or disturbance sets. Since plant parameter and\\/or disturbance uncertainty is anyhow the basic problem in feedback design, this eliminates to a large extent the differences between linear and nonlinear systems. If

  5. Fixed point theory and semidefinite programming for computable performance analysis of block-sparsity recovery

    Microsoft Academic Search

    Gongguo Tang; Arye Nehorai

    2011-01-01

    In this paper, we employ fixed point theory and semidefinite programming to compute the performance bounds on convex block-sparsity recovery algorithms. As a prerequisite for optimal sensing matrix design, a computable performance bound would open doors for wide applications in sensor arrays, radar, DNA microarrays, and many other areas where block-sparsity arises naturally. We define a family of goodness measures

  6. About the Proof-Theoretic Ordinals of Weak Fixed Point Theories

    Microsoft Academic Search

    Gerhard Jäger; Barbara Primo

    1992-01-01

    This paper presents several proof-theoretic results concerning weak fixed point theories over second order number theory with arithmetic comprehension and full or restricted induction on the natural numbers. It is also shown that there are natural second order theories which are proof-theoretically equivalent but have different proof-theoretic ordinals.

  7. Approximation methods in equilibrium and fixed point theory Proximally nondegenerate sets

    Microsoft Academic Search

    Bernard CORNET; Marc-Olivier CZARNECKI

    The aim of this paper is to show how approximation methods allow to extend the Equilibrium and Fixed Point Theory to the nonsmooth and nonconvex setting. Our approach relies heavily on the use of the distance function dM to a set M. We show that, for our purpose, Clarke's subdierential @dM is too big, and that the appropriate notion is

  8. The non-constructive ? operator, fixed point theories with ordinals, and the bar rule

    Microsoft Academic Search

    Thomas Strahm

    2000-01-01

    This paper deals with the proof theory of first-order applicative theories with non-constructive ? operator and a form of the bar rule, yielding systems of ordinal strength ?0 and ?20, respectively. Relevant use is made of fixed-point theories with ordinals plus bar rule.

  9. Fixed point controllers and stabilization of the cart-pole system and the rotating pendulum

    Microsoft Academic Search

    Reza Olfati-Saber

    1999-01-01

    We consider stabilization of nonlinear systems in a special normal form as the cascade of a nonlinear subsystem and a linear subsystem. These systems do not possess any particular triangular structure. Despite this fact, we show how a backstepping type procedure applied to these systems naturally leads to a fixed point equation in the control input. We give conditions for

  10. Synthetic foundations of cevian geometry, I: Fixed points of affine maps in triangle geometry

    E-print Network

    Igor Minevich; Patrick Morton

    2015-03-29

    We give synthetic proofs of many new results in triangle geometry, focusing especially on fixed points of certain affine maps which are defined in terms of the cevian triangle $DEF$ of a point $P$ with respect to a given triangle $ABC$, as well as the cevian triangle of the isotomic conjugate $P'$ of $P$ with respect to $ABC$. We prove a formula for the cyclocevian map in terms of the isotomic and isogonal maps using an entirely synthetic argument, and show that the complement $Q$ of the isotomic conjugate $P'$ has many interesting properties. If $T_P$ is the affine map taking $ABC$ to $DEF$, we show synthetically that $Q$ is the unique ordinary fixed point of $T_P$ when $P$ is any point not lying on the sides of triangle $ABC$, its anti-complementary triangle, or the Steiner circumellipse of $ABC$. We also show that $T_P(Q')=P$ if $Q'$ is the complement of $P$, and that the affine map $T_P T_{P'}$ is either a homothety or a translation which always has the $P$-ceva conjugate of $Q$ as a fixed point. Finally, we show that $P$ lies on the Steiner circumellipse if and only if $T_PT_{P'}=K^{-1}$, where $K$ is the complement map for $ABC$. This paper forms the foundation for several more papers to follow, in which the conic on the 5 points $A,B,C,P,Q$ is studied and its center is characterized as a fixed point of the map $\\lambda=T_{P'} T_P^{-1}$.

  11. Collective fixed points, generalized games and systems of generalized quasi-variational inclusion problems in topological spaces

    Microsoft Academic Search

    Xie Ping Ding

    2010-01-01

    In this paper, by using a fixed point theorem for expansive set-valued mappings with noncompact and nonconvex domains and ranges in topological spaces due to the author, we first prove a collective fixed point theorem and an existence theorem of equilibrium points for a generalized game. As applications, some new existence theorems of solutions for systems of generalized quasi-variational inclusion

  12. On the creation of Wada basins in interval maps through fixed point tangent bifurcation

    NASA Astrophysics Data System (ADS)

    Breban, Romulus; Nusse, Helena E.

    2005-07-01

    Basin boundaries play an important role in the study of dynamics of nonlinear models in a variety of disciplines such as biology, chemistry, economics, engineering, and physics. One of the goals of nonlinear dynamics is to determine the global structure of the system such as boundaries of basins. A basin having the strange property that every point which is on the boundary of that basin is on the boundary of at least three different basins, is called a Wada basin, and its boundary is called a Wada basin boundary. Here we consider maps on the interval. We present a sufficient and necessary condition guaranteeing that three Wada basins are emerging from a tangent bifurcation for certain one-dimensional maps having negative Schwarzian derivative, two fixed point attractors on one side of the tangent bifurcation, and three fixed point attractors on the other side of the tangent bifurcation. All the conditions involved are numerically verifiable.

  13. Video-Based Point Cloud Generation Using Multiple Action Cameras

    NASA Astrophysics Data System (ADS)

    Teo, T.

    2015-05-01

    Due to the development of action cameras, the use of video technology for collecting geo-spatial data becomes an important trend. The objective of this study is to compare the image-mode and video-mode of multiple action cameras for 3D point clouds generation. Frame images are acquired from discrete camera stations while videos are taken from continuous trajectories. The proposed method includes five major parts: (1) camera calibration, (2) video conversion and alignment, (3) orientation modelling, (4) dense matching, and (5) evaluation. As the action cameras usually have large FOV in wide viewing mode, camera calibration plays an important role to calibrate the effect of lens distortion before image matching. Once the camera has been calibrated, the author use these action cameras to take video in an indoor environment. The videos are further converted into multiple frame images based on the frame rates. In order to overcome the time synchronous issues in between videos from different viewpoints, an additional timer APP is used to determine the time shift factor between cameras in time alignment. A structure form motion (SfM) technique is utilized to obtain the image orientations. Then, semi-global matching (SGM) algorithm is adopted to obtain dense 3D point clouds. The preliminary results indicated that the 3D points from 4K video are similar to 12MP images, but the data acquisition performance of 4K video is more efficient than 12MP digital images.

  14. Modeling of Transient Heat Transfer in Temperature Fixed Points: Indium Cell Design

    NASA Astrophysics Data System (ADS)

    Le Sant, V.; Morice, R.; Failleau, G.

    2008-10-01

    Laboratoire national de métrologie et d’essais has recently constructed a new device to realize the indium fixed point adiabatically. In parallel, a numerical heat transfer model has been developed as an aid to understanding its thermal behavior. This transient axially symmetric two-dimensional (2D) model simulates the melting process using the apparent specific heat method; the effects of mixing and convection within the liquid phase of indium are not taken into account. The thermal parameters, the nonuniformity of the furnace, and the thermal control of the surroundings were assessed with the aim of reducing parasitic heat exchanges. The results of the modeling are in good agreement with the measurements and clarify the parasitic heat flux observed during the phase transition. This article describes the model and the first results obtained. The model is a helpful tool in evaluating future technical improvements of the enclosure used to realize the indium fixed point.

  15. Probability of local bifurcation type from a fixed point: A random matrix perspective

    E-print Network

    D. J. Albers; J. C. Sprott

    2005-10-24

    Results regarding probable bifurcations from fixed points are presented in the context of general dynamical systems (real, random matrices), time-delay dynamical systems (companion matrices), and a set of mappings known for their properties as universal approximators (neural networks). The eigenvalue spectra is considered both numerically and analytically using previous work of Edelman et. al. Based upon the numerical evidence, various conjectures are presented. The conclusion is that in many circumstances, most bifurcations from fixed points of large dynamical systems will be due to complex eigenvalues. Nevertheless, surprising situations are presented for which the aforementioned conclusion is not general, e.g. real random matrices with Gaussian elements with a large positive mean and finite variance.

  16. Fixed-Point Quantum Search with an Optimal Number of Queries

    NASA Astrophysics Data System (ADS)

    Yoder, Theodore J.; Low, Guang Hao; Chuang, Isaac L.

    2014-11-01

    Grover's quantum search and its generalization, quantum amplitude amplification, provide a quadratic advantage over classical algorithms for a diverse set of tasks but are tricky to use without knowing beforehand what fraction ? of the initial state is comprised of the target states. In contrast, fixed-point search algorithms need only a reliable lower bound on this fraction but, as a consequence, lose the very quadratic advantage that makes Grover's algorithm so appealing. Here we provide the first version of amplitude amplification that achieves fixed-point behavior without sacrificing the quantum speedup. Our result incorporates an adjustable bound on the failure probability and, for a given number of oracle queries, guarantees that this bound is satisfied over the broadest possible range of ? .

  17. Fixed-point quantum search with an optimal number of queries.

    PubMed

    Yoder, Theodore J; Low, Guang Hao; Chuang, Isaac L

    2014-11-21

    Grover's quantum search and its generalization, quantum amplitude amplification, provide a quadratic advantage over classical algorithms for a diverse set of tasks but are tricky to use without knowing beforehand what fraction ? of the initial state is comprised of the target states. In contrast, fixed-point search algorithms need only a reliable lower bound on this fraction but, as a consequence, lose the very quadratic advantage that makes Grover's algorithm so appealing. Here we provide the first version of amplitude amplification that achieves fixed-point behavior without sacrificing the quantum speedup. Our result incorporates an adjustable bound on the failure probability and, for a given number of oracle queries, guarantees that this bound is satisfied over the broadest possible range of ?. PMID:25479481

  18. Fixed-point quantum search with an optimal number of queries

    E-print Network

    Theodore J. Yoder; Guang Hao Low; Isaac L. Chuang

    2014-11-24

    Grover's quantum search and its generalization, quantum amplitude amplification, provide quadratic advantage over classical algorithms for a diverse set of tasks, but are tricky to use without knowing beforehand what fraction $\\lambda$ of the initial state is comprised of the target states. In contrast, fixed-point search algorithms need only a reliable lower bound on this fraction, but, as a consequence, lose the very quadratic advantage that makes Grover's algorithm so appealing. Here we provide the first version of amplitude amplification that achieves fixed-point behavior without sacrificing the quantum speedup. Our result incorporates an adjustable bound on the failure probability, and, for a given number of oracle queries, guarantees that this bound is satisfied over the broadest possible range of $\\lambda$.

  19. Quadratic recurrence equations - exact explicit solution of period four fixed points functions in bifurcation diagram

    E-print Network

    Gvozden Rukavina

    2008-02-19

    This article presents the exact solution of fixed points functions for the cycle of period four of the quadratic recurrence equations. The solution is demonstrated for the quadratic map and the logistic map. These recurrence equations, presenting the real domain, as well as the Mandelbrot set, presenting the complex domain, are at the very heart of dynamical systems and chaos theory. Up to now, the closed explicit solutions of fixed points functions have only been known for three bifurcation ranges: for the cycles of period one, two and three. With the discovery of the solution for cycle four, disclosed in this paper, further step has been made in our comprehension of simultaneous complexity and simplicity which represents the beauty of nature.

  20. Single current sensor operation with fixed sampling points based on TSPWM

    Microsoft Academic Search

    Xiaomeng Cheng; Haifeng Lu; Wenlong Qu

    2010-01-01

    The single current sensor operation (SCSO) is favorable for cost reduction and fault-tolerance purposes in three-phase inverter-driven systems. This paper addresses a SCSO method based on tri-state pulse-width modulation technique (TSPWM). It enables fixed sampling points with minimal hardware and software requirements. Simultaneous three phase currents can be easily computed due to symmetrical sampling. No change to TSPWM is needed

  1. The algebraic multigrid projection for eigenvalue problems; backrotations and multigrid fixed points

    NASA Technical Reports Server (NTRS)

    Costiner, Sorin; Taasan, Shlomo

    1994-01-01

    The periods of the theorem for the algebraic multigrid projection (MGP) for eigenvalue problems, and of the multigrid fixed point theorem for multigrid cycles combining MGP with backrotations, are presented. The MGP and the backrotations are central eigenvector separation techniques for multigrid eigenvalue algorithms. They allow computation on coarse levels of eigenvalues of a given eigenvalue problem, and are efficient tools in the computation of eigenvectors.

  2. Removing Lead From Drinking Water With a Point-of-Use GAC Fixed-Bed Adsorber

    Microsoft Academic Search

    Roy W. Kuennen; Roy M. Taylor; Karl Van Dyke; Kevin Groenevelt

    1992-01-01

    An evaluation was carried out of a point-of-use (POU) granular activated carbon (GAC) fixed-bed adsorber (FBA) for removing soluble and insoluble lead from drinking water. Several factors affected the removal of lead from water by GAC, including carbon type, particle size distribution, solution pH, contact time of water with GAC, surface loading of lead onto GAC, competitive interactions with other

  3. Strong convergence algorithm for split equilibrium problems and hierarchical fixed point problems.

    PubMed

    Bnouhachem, Abdellah

    2014-01-01

    The purpose of this paper is to investigate the problem of finding the approximate element of the common set of solutions of a split equilibrium problem and a hierarchical fixed point problem in a real Hilbert space. We establish the strong convergence of the proposed method under some mild conditions. Several special cases are also discussed. Our main result extends and improves some well-known results in the literature. PMID:24701164

  4. 5d fixed points from brane webs and O7-planes

    E-print Network

    Oren Bergman; Gabi Zafrir

    2015-07-14

    We explore the properties of five-dimensional supersymmetric gauge theories living on 5-brane webs in orientifold 7-plane backgrounds. These include $USp(2N)$ and $SO(N)$ gauge theories with fundamental matter, as well as $SU(N)$ gauge theories with symmetric and antisymmetric matter. We find a number of new 5d fixed point theories that feature enhanced global symmetries. We also exhibit a number of new 5d dualities.

  5. One-Parameter Fixed-Point Theory and Gradient Flows of Closed 1Forms

    Microsoft Academic Search

    D. Schütz

    2002-01-01

    We use the one-parameter fixed-point theory of Geoghegan and Nicas to get information about the closed orbit structure of transverse gradient flows of closed 1-forms on a closed manifold M. We define a noncommutative zeta function in an object related to the first Hochschild homology group of the Novikov ring associated to the 1-form and relate it to the torsion

  6. Application of fixed point theory to chaotic attractors of forced oscillators

    Microsoft Academic Search

    H. Bruce Stewart

    1991-01-01

    A review of the structure of chaotic attractors of periodically forced second-order nonlinear oscillators suggests that the\\u000a theory of fixed points of transformations gives information about the fundamental topological structure of attractors. First\\u000a a simple extension of the Levinson index formula is proved. Then numerical evidence is used to formulate plausible conjectures\\u000a about absorbing regions containing chaotic attractors in forced

  7. BOUNDEDNESS AND STABILITY IN NONLINEAR DELAY DIFFERENCE EQUATIONS EMPLOYING FIXED POINT THEORY

    Microsoft Academic Search

    MUHAMMAD N. ISLAM; ERNEST YANKSON

    2005-01-01

    In this paper we study stability and boundedness of the nonlinear dierence equation x(t + 1) = a(t)x(t) + c(t) x(t g(t)) + q(x(t); x(t g(t)) : In particular we study equi-boundedness of solutions and the stability of the zero solution of this equation. Fixed point theorems are used in the analysis. Liapunov's method is normally used to study the

  8. Applications of General Infimum Principles to Fixed-Point Theory and Game Theory

    Microsoft Academic Search

    W?adys?aw Kulpa; Andrzej Szymanski

    2008-01-01

    The main result of the paper is a series of theorems, called here Infimum Principles. As applications, we derive some well-known\\u000a results related to fixed point, minimax, and equilibrium theorems including the Nash equilibrium theorem and Gale–Nikaido\\u000a theorem. Our study is based on and utilizes the techniques of simplicial structures and CO families. This approach enables\\u000a us to derive not

  9. Perturbed pendulum-like motions of a rigid body about a fixed point

    E-print Network

    Igor N. Gashenenko

    2012-12-09

    This paper is devoted to a detailed investigation of the perturbed pendulum-like motions of a heavy rigid body about a fixed point. Canonical variables that allow one to simplify the analysis of homoclinic and heteroclinic orbits are introduced. Characteristic properties of perturbed pendulum-like motions of the body in inertial space are studied. A qualitative description of asymptotics of pendulum-like motions in a neighbourhood of split separatrices is given.

  10. New Experimental Technique for the Study of Phase Transition Evolution in Fixed-Point Cells

    NASA Astrophysics Data System (ADS)

    Nemeth, T.; Nemeth, S.; Turzo-Andras, E.

    2015-04-01

    A new advanced technique was developed at the Hungarian Metrological Institute (MKEH), devoted to optimizing the realization of the International Temperature Scale ITS-90. The work was performed within the framework of the European project "Novel techniques for traceable temperature dissemination." The paper is devoted to describing this new measurement technique and its setup. The time evolution of the solid fraction and melt fraction along the phase transformation has been followed, using a technique based on the difference of the electrical conductivity between the solid and liquid phases of the metal. The measurement technique provides electrical signals, which are suitable for improving the quality of the freezing plateaus realized in the case of different fixed-point realizations, covering the temperature range from -39°C to 962°C. The ideal section of the freezing plateau can be maintained by ensuring a continuous flow of mass and energy of the fixed-point substance in the axial direction. The intervention is achieved by modifying the temperatures of the different zones of the furnace controller with more degrees, with the aid of developed intervening devices. Recent developments permit the selection of the ideal section of a freezing plateau and, what is more, the increase of this plateau section to practically unlimited for all metal fixed points.

  11. A study about the fitting curves for the calibration of the Pt/Rh family thermocouples in fixed points

    NASA Astrophysics Data System (ADS)

    del Campo, D.; García, C.

    2013-09-01

    The aim of this paper is to study the suitability of the common procedures used to estimate the calibration fitting curves of noble metal thermocouples, namely from the Pt/Rh family, in fixed points. The objective is to find out the best combination and the minimum number of fixed points that allows obtaining a reasonable interpolation uncertainty.

  12. Isotopic effects in the neon fixed point: uncertainty of the calibration data correction

    NASA Astrophysics Data System (ADS)

    Steur, Peter P. M.; Pavese, Franco; Fellmuth, Bernd; Hermier, Yves; Hill, Kenneth D.; Seog Kim, Jin; Lipinski, Leszek; Nagao, Keisuke; Nakano, Tohru; Peruzzi, Andrea; Sparasci, Fernando; Szmyrka-Grzebyk, Anna; Tamura, Osamu; Tew, Weston L.; Valkiers, Staf; van Geel, Jan

    2015-02-01

    The neon triple point is one of the defining fixed points of the International Temperature Scale of 1990 (ITS-90). Although recognizing that natural neon is a mixture of isotopes, the ITS-90 definition only states that the neon should be of ‘natural isotopic composition’, without any further requirements. A preliminary study in 2005 indicated that most of the observed variability in the realized neon triple point temperatures within a range of about 0.5?mK can be attributed to the variability in isotopic composition among different samples of ‘natural’ neon. Based on the results of an International Project (EUROMET Project No. 770), the Consultative Committee for Thermometry decided to improve the realization of the neon fixed point by assigning the ITS-90 temperature value 24.5561?K to neon with the isotopic composition recommended by IUPAC, accompanied by a quadratic equation to take the deviations from the reference composition into account. In this paper, the uncertainties of the equation are discussed and an uncertainty budget is presented. The resulting standard uncertainty due to the isotopic effect (k = 1) after correction of the calibration data is reduced to (4 to 40)??K when using neon of ‘natural’ isotopic composition or to 30??K when using 20Ne. For comparison, an uncertainty component of 0.15?mK should be included in the uncertainty budget for the neon triple point if the isotopic composition is unknown, i.e. whenever the correction cannot be applied.

  13. A primal-dual fixed point algorithm for convex separable minimization with applications to image restoration

    NASA Astrophysics Data System (ADS)

    Chen, Peijun; Huang, Jianguo; Zhang, Xiaoqun

    2013-02-01

    Recently, the minimization of a sum of two convex functions has received considerable interest in a variational image restoration model. In this paper, we propose a general algorithmic framework for solving a separable convex minimization problem from the point of view of fixed point algorithms based on proximity operators (Moreau 1962 C. R. Acad. Sci., Paris I 255 2897-99). Motivated by proximal forward-backward splitting proposed in Combettes and Wajs (2005 Multiscale Model. Simul. 4 1168-200) and fixed point algorithms based on the proximity operator (FP2O) for image denoising (Micchelli et al 2011 Inverse Problems 27 45009-38), we design a primal-dual fixed point algorithm based on the proximity operator (PDFP2O? for ? ? [0, 1)) and obtain a scheme with a closed-form solution for each iteration. Using the firmly nonexpansive properties of the proximity operator and with the help of a special norm over a product space, we achieve the convergence of the proposed PDFP2O? algorithm. Moreover, under some stronger assumptions, we can prove the global linear convergence of the proposed algorithm. We also give the connection of the proposed algorithm with other existing first-order methods. Finally, we illustrate the efficiency of PDFP2O? through some numerical examples on image supper-resolution, computerized tomographic reconstruction and parallel magnetic resonance imaging. Generally speaking, our method PDFP2O (? = 0) is comparable with other state-of-the-art methods in numerical performance, while it has some advantages on parameter selection in real applications.

  14. Infrared behavior and fixed-point structure in the compactified Ginzburg--Landau model

    E-print Network

    C. A. Linhares; A. P. C. Malbouisson; M. L. Souza

    2011-02-07

    We consider the Euclidean $N$-component Ginzburg--Landau model in $D$ dimensions, of which $d$ ($d\\leq D$) of them are compactified. As usual, temperature is introduced through the mass term in the Hamiltonian. This model can be interpreted as describing a system in a region of the $D$-dimensional space, limited by $d$ pairs of parallel planes, orthogonal to the coordinates axis $x_1,\\,x_2,\\,...,\\,x_d$. The planes in each pair are separated by distances $L_1,\\;L_2,\\; ...,\\,L_d$. For $D=3$, from a physical point of view, the system can be supposed to describe, in the cases of $d=1$, $d=2$, and $d=3$, respectively, a superconducting material in the form of a film, of an infinitely long wire having a retangular cross-section and of a brick-shaped grain. We investigate in the large-$N$ limit the fixed-point structure of the model, in the absence or presence of an external magnetic field. An infrared-stable fixed point is found, whether of not an external magnetic field is applied, but for different ranges of values of the space dimension $ D$.

  15. Ultraviolet fixed point and massive composite particles in TeV scales

    E-print Network

    She-Sheng Xue

    2014-09-02

    We present a further study of the dynamics of high-dimension fermion operators attributed to the theoretical inconsistency of the fundamental cutoff (quantum gravity) and the parity-violating gauge symmetry of the standard model. Studying the phase transition from a symmetry-breaking phase to a strong-coupling symmetric phase and the $\\beta$-function behavior in terms of four-fermion coupling strength, we discuss the critical transition point as a ultraviolet-stable fixed point where a quantum field theory preserving the standard model gauge symmetry with composite particles can be realized. The form-factors and masses of composite particles at TeV scales are estimated by extrapolating the solution of renormalization-group equations from the infrared-stable fixed point where the quantum field theory of standard model is realized and its phenomenology including Higgs mass has been experimentally determined. We discuss the probability of composite-particle formation and decay that could be experimentally verified in the LHC by measuring the invariant mass of relevant final states and their peculiar kinetic distributions.

  16. Global fixed point proof of time-dependent density-functional theory

    E-print Network

    Michael Ruggenthaler; Robert van Leeuwen

    2011-04-20

    We reformulate and generalize the uniqueness and existence proofs of time-dependent density-functional theory. The central idea is to restate the fundamental one-to-one correspondence between densities and potentials as a global fixed point question for potentials on a given time-interval. We show that the unique fixed point, i.e. the unique potential generating a given density, is reached as the limiting point of an iterative procedure. The one-to-one correspondence between densities and potentials is a straightforward result provided that the response function of the divergence of the internal forces is bounded. The existence, i.e. the v-representability of a density, can be proven as well provided that the operator norms of the response functions of the members of the iterative sequence of potentials have an upper bound. The densities under consideration have second time-derivatives that are required to satisfy a condition slightly weaker than being square-integrable. This approach avoids the usual restrictions of Taylor-expandability in time of the uniqueness theorem by Runge and Gross [Phys.Rev.Lett.52, 997 (1984)] and of the existence theorem by van Leeuwen [Phys.Rev.Lett. 82, 3863 (1999)]. Owing to its generality, the proof not only answers basic questions in density-functional theory but also has potential implications in other fields of physics.

  17. Estimating the Contribution of Impurities to the Uncertainty of Metal Fixed-Point Temperatures

    NASA Astrophysics Data System (ADS)

    Hill, K. D.

    2014-04-01

    The estimation of the uncertainty component attributable to impurities remains a central and important topic of fixed-point research. Various methods are available for this estimation, depending on the extent of the available information. The sum of individual estimates method has considerable appeal where there is adequate knowledge of the sensitivity coefficients for each of the impurity elements and sufficiently low uncertainty regarding their concentrations. The overall maximum estimate (OME) forsakes the behavior of the individual elements by assuming that the cryoscopic constant adequately represents (or is an upper bound for) the sensitivity coefficients of the individual impurities. Validation of these methods using melting and/or freezing curves is recommended to provide confidence. Recent investigations of indium, tin, and zinc fixed points are reported. Glow discharge mass spectrometry was used to determine the impurity concentrations of the metals used to fill the cells. Melting curves were analyzed to derive an experimental overall impurity concentration (assuming that all impurities have a sensitivity coefficient equivalent to that of the cryoscopic constant). The two values (chemical and experimental) for the overall impurity concentrations were then compared. Based on the data obtained, the pragmatic approach of choosing the larger of the chemical and experimentally derived quantities as the best estimate of the influence of impurities on the temperature of the freezing point is suggested rather than relying solely on the chemical analysis and the OME method to derive the uncertainty component attributable to impurities.

  18. c-theorem violation for effective central charge of infinite-randomness fixed points

    NASA Astrophysics Data System (ADS)

    Fidkowski, L.; Refael, G.; Bonesteel, N. E.; Moore, J. E.

    2008-12-01

    Topological insulators supporting non-Abelian anyonic excitations are in the center of attention as candidates for topological quantum computation. In this paper, we analyze the ground-state properties of disordered non-Abelian anyonic chains. The resemblance of fusion rules of non-Abelian anyons and real-space decimation strongly suggests that disordered chains of such anyons generically exhibit infinite-randomness phases. Concentrating on the disordered golden chain model with nearest-neighbor coupling, we show that Fibonacci anyons with the fusion rule ???=1?? exhibit two infinite-randomness phases: a random-singlet phase when all bonds prefer the trivial fusion channel and a mixed phase which occurs whenever a finite density of bonds prefers the ? fusion channel. Real-space renormalization-group (RG) analysis shows that the random-singlet fixed point is unstable to the mixed fixed point. By analyzing the entanglement entropy of the mixed phase, we find its effective central charge and find that it increases along the RG flow from the random-singlet point, thus ruling out a c theorem for the effective central charge.

  19. The Open-Source Fixed-Point Model Checker for Symbolic Analysis of Security Protocols

    Microsoft Academic Search

    Sebastian Mödersheim; Luca Viganò

    2009-01-01

    We introduce the Open-source Fixed-point Model Checker OFMC for symbolic security protocol analysis, which extends the On-the-fly\\u000a Model Checker (the previous OFMC). The native input language of OFMC is the AVISPA Intermediate Format IF. OFMC also supports\\u000a AnB, a new Alice-and-Bob-style language that extends previous similar languages with support for algebraic properties of cryptographic\\u000a operators and with a simple notation

  20. The infrared fixed point of Landau gauge Yang-Mills theory

    E-print Network

    Axel Weber

    2012-11-07

    Over the last decade, the infrared behavior of Yang-Mills theory in the Landau gauge has been scrutinized with the help of Dyson-Schwinger equations and lattice calculations. In this contribution, we describe a technically simple approach to the deep infrared regime via Callan-Symanzik renormalization group equations in an epsilon expansion. This approach recovers, in an analytical and systematically improvable way, all the solutions previously found as solutions of the Dyson-Schwinger equations and singles out the solution favored by lattice calculations as the infrared-stable fixed point (for space-time dimensions above two).

  1. $?I=1/2$ rule for kaon decays derived from QCD infrared fixed point

    E-print Network

    R. J. Crewther; Lewis C. Tunstall

    2015-02-24

    This article gives details of our proposal to replace ordinary chiral $SU(3)_L\\times SU(3)_R$ perturbation theory $\\chi$PT$_3$ by 3-flavor chiral-scale perturbation theory $\\chi$PT$_\\sigma$. In $\\chi$PT$_\\sigma$, amplitudes are expanded at low energies and small $u,d,s$ quark masses about an infrared fixed point $\\alpha^{}_\\mathrm{IR}$ of 3-flavor QCD. At $\\alpha^{}_\\mathrm{IR}$, the quark condensate $\\langle \\bar{q}q\\rangle_{\\mathrm{vac}} \

  2. Global solutions of functional fixed point equations via pseudo-spectral methods

    E-print Network

    Julia Borchardt; Benjamin Knorr

    2015-02-26

    We apply pseudo-spectral methods to construct global solutions of functional renormalisation group equations in field space to high accuracy. For this, we introduce a basis to resolve both finite as well as asymptotic regions of effective potentials. Our approach is benchmarked using the critical behaviour of the scalar $O(1)$ model, providing results for the global fixed point potential as well as leading critical exponents and their respective global eigenfunctions. We provide new results for (1) multi-critical $O(1)$ models in fractional dimensions, (2) the three-dimensional Gross-Neveu model at both small and large $N$, and (3) the scalar-tensor model, also in three dimensions.

  3. Nonthermal Fixed Points: Effective Weak Coupling for Strongly Correlated Systems Far from Equilibrium

    NASA Astrophysics Data System (ADS)

    Berges, Jürgen; Rothkopf, Alexander; Schmidt, Jonas

    2008-07-01

    Strongly correlated systems far from equilibrium can exhibit scaling solutions with a dynamically generated weak coupling. We show this by investigating isolated systems described by relativistic quantum field theories for initial conditions leading to nonequilibrium instabilities, such as parametric resonance or spinodal decomposition. The nonthermal fixed points prevent fast thermalization if classical-statistical fluctuations dominate over quantum fluctuations. We comment on the possible significance of these results for the heating of the early Universe after inflation and the question of fast thermalization in heavy-ion collision experiments.

  4. Stability analysis of coupled map lattices at locally unstable fixed points

    E-print Network

    H. Atmanspacher; T. Filk; H. Scheingraber

    2005-02-11

    Numerical simulations of coupled map lattices (CMLs) and other complex model systems show an enormous phenomenological variety that is difficult to classify and understand. It is therefore desirable to establish analytical tools for exploring fundamental features of CMLs, such as their stability properties. Since CMLs can be considered as graphs, we apply methods of spectral graph theory to analyze their stability at locally unstable fixed points for different updating rules, different coupling scenarios, and different types of neighborhoods. Numerical studies are found to be in excellent agreement with our theoretical results.

  5. HOMOCLINIC POINTS OF ALGEBRAIC Z d ACTIONS DOUGLAS LIND AND KLAUS SCHMIDT

    E-print Network

    Lind, Douglas A.

    properties for such actions. This provides an extensive class of examples of Z d ­actions to which RuelleHOMOCLINIC POINTS OF ALGEBRAIC Z d ­ACTIONS DOUGLAS LIND AND KLAUS SCHMIDT Abstract. Let # be an action of Z d by continuous automorphisms of a compact abelian group X. A point x in X is called

  6. Quasi-gaussian fixed points and factorial cumulants in nuclear multifragmentation

    E-print Network

    D. Lacroix; R. Peschanski

    1996-06-11

    We re-analyze the conditions for the phenomenon of intermittency (self-similar fluctuations) to occur in models of multifragmentation. Analyzing two different mechanisms, the bond-percolation and the ERW (Elattari, Richert and Wagner) statistical fragmentation models, we point out a common quasi-gaussian shape of the total multiplicity distribution in the critical range. The fixed-point property is also observed for the multiplicity of the second bin. Fluctuations are studied using scaled factorial cumulants instead of scaled factorial moments. The second-order cumulant displays the intermittency signal while higher order cumulants are equal to zero, revealing a large information redundancy in scaled factorial moments. A practical criterion is proposed to identify the gaussian feature of light-fragment production, distinguishing between a self-similarity mechanism (ERW) and the superposition of independent sources (percolation).

  7. Development of a new radiometer for the thermodynamic measurement of high temperature fixed points

    SciTech Connect

    Dury, M. R.; Goodman, T. M.; Lowe, D. H.; Machin, G.; Woolliams, E. R. [National Physical Laboratory, Teddington (United Kingdom)] [National Physical Laboratory, Teddington (United Kingdom)

    2013-09-11

    The National Physical Laboratory (NPL) has developed a new radiometer to measure the thermodynamic melting point temperatures of high temperature fixed points with ultra-low uncertainties. In comparison with the NPL's Absolute Radiation Thermometer (ART), the 'THermodynamic Optical Radiometer' (THOR) is more portable and compact, with a much lower size-of-source effect and improved performance in other parameters such as temperature sensitivity. It has been designed for calibration as a whole instrument via the radiance method, removing the need to calibrate the individual subcomponents, as required by ART, and thereby reducing uncertainties. In addition, the calibration approach has been improved through a new integrating sphere that has been designed to have greater uniformity.

  8. Optimization of the thermogauge furnace for realizing high temperature fixed points

    SciTech Connect

    Wang, T.; Dong, W. [National Institute of Metrology (NIM), Beijing (China)] [National Institute of Metrology (NIM), Beijing (China); Liu, F. [AVIC China Precision Engineering Institute for Aircraft Industry, Beijing (China)] [AVIC China Precision Engineering Institute for Aircraft Industry, Beijing (China)

    2013-09-11

    The thermogauge furnace was commonly used in many NMIs as a blackbody source for calibration of the radiation thermometer. It can also be used for realizing the high temperature fixed point(HTFP). According to our experience, when realizing HTFP we need the furnace provide relative good temperature uniformity to avoid the possible damage to the HTFP. To improve temperature uniformity in the furnace, the furnace tube was machined near the tube ends with a help of a simulation analysis by 'ansys workbench'. Temperature distributions before and after optimization were measured and compared at 1300 °C, 1700°C, 2500 °C, which roughly correspond to Co-C(1324 °C), Pt-C(1738 °C) and Re-C(2474 °C), respectively. The results clearly indicate that through machining the tube the temperature uniformity of the Thermogage furnace can be remarkably improved. A Pt-C high temperature fixed point was realized in the modified Thermogauge furnace subsequently, the plateaus were compared with what obtained using old heater, and the results were presented in this paper.

  9. A Method to Improve the Temperature Distribution of Holder Around the Fixed-Point Cell Position

    NASA Astrophysics Data System (ADS)

    Lim, S. D.; Karmalawi, A. M.; Salim, S. G. R.; Soliman, M. A.; Kim, B. H.; Lee, D. H.; Yoo, Y. S.

    2014-07-01

    The temperature profile along the furnaces used in heating high-temperature fixed points has a crucial impact on the quality and duration of melting plateaux, accordingly the accuracy of thermodynamic temperature determination of such fixed points. This paper describes a simple, yet efficient, approach for improving the temperature uniformity along a cell holder in high-temperature blackbody (HTBB) furnaces that use pyrolytic graphite rings as heating elements. The method has been applied on the KRISS' HTBB furnace. In this work, an ideal solution for arranging the heating elements inside the furnace is presented by which the temperature gradient across the cell holder can be kept as low as possible. Numerical calculations, based on a finite element method, have been carried out to find the best possible arrangement of the rings. This has been followed by measuring the temperature gradient along an empty cell holder to validate our calculations. A temperature gradient of 100 mK has been achieved at over a length of 50 mm within a cell holder of 10 cm in length. It has also been shown that for a 20 cm long holder surrounded by rings with an arbitrary resistance profile, the temperature uniformity can be improved by adding a few "hot" rings around the cell holder.

  10. Stability of a cubic fixed point in three dimensions. Critical exponents for generic N

    E-print Network

    Konstantin Varnashev

    2000-03-04

    The detailed analysis of the global structure of the renormalization-group (RG) flow diagram for a model with isotropic and cubic interactions is carried out in the framework of the massive field theory directly in three dimensions (3D) within an assumption of isotropic exchange. Perturbative expansions for RG functions are calculated for arbitrary $N$ up to the four-loop order and resummed by means of the generalized Pad$\\acute{\\rm e}$-Borel-Leroy technique. Coordinates and stability matrix eigenvalues for the cubic fixed point are found under the optimal value of the transformation parameter. Critical dimensionality of the model is proved to be equal to $N_c=2.89 \\pm 0.02$ that agrees well with the estimate obtained on the basis of the five-loop $\\ve$-expansion [H. Kleinert and V. Schulte-Frohlinde, Phys. Lett. B342, 284 (1995)] resummed by the above method. As a consequence, the cubic fixed point should be stable in 3D for $N\\ge3$, and the critical exponents controlling phase transitions in three-dimensional magnets should belong to the cubic universality class. The critical behavior of the random Ising model being the nontrivial particular case of the cubic model when N=0 is also investigated. For all physical quantities of interest the most accurate numerical estimates with their error bounds are obtained. The results achieved in the work are discussed along with the predictions given by other theoretical approaches and experimental data.

  11. Very low cost real time histogram-based contrast enhancer utilizing fixed-point DSP processing

    NASA Astrophysics Data System (ADS)

    McCaffrey, Nathaniel J.; Pantuso, Francis P.

    1998-03-01

    A real time contrast enhancement system utilizing histogram- based algorithms has been developed to operate on standard composite video signals. This low-cost DSP based system is designed with fixed-point algorithms and an off-chip look up table (LUT) to reduce the cost considerably over other contemporary approaches. This paper describes several real- time contrast enhancing systems advanced at the Sarnoff Corporation for high-speed visible and infrared cameras. The fixed-point enhancer was derived from these high performance cameras. The enhancer digitizes analog video and spatially subsamples the stream to qualify the scene's luminance. Simultaneously, the video is streamed through a LUT that has been programmed with the previous calculation. Reducing division operations by subsampling reduces calculation- cycles and also allows the processor to be used with cameras of nominal resolutions. All values are written to the LUT during blanking so no frames are lost. The enhancer measures 13 cm X 6.4 cm X 3.2 cm, operates off 9 VAC and consumes 12 W. This processor is small and inexpensive enough to be mounted with field deployed security cameras and can be used for surveillance, video forensics and real- time medical imaging.

  12. Dipeptide Aggregation in Aqueous Solution from Fixed Point-Charge Force Fields.

    PubMed

    Götz, Andreas W; Bucher, Denis; Lindert, Steffen; McCammon, J Andrew

    2014-04-01

    The description of aggregation processes with molecular dynamics simulations is a playground for testing biomolecular force fields, including a new generation of force fields that explicitly describe electronic polarization. In this work, we study a system consisting of 50 glycyl-l-alanine (Gly-Ala) dipeptides in solution with 1001 water molecules. Neutron diffraction experiments have shown that at this concentration, Gly-Ala aggregates into large clusters. However, general-purpose force fields in combination with established water models can fail to correctly describe this aggregation process, highlighting important deficiencies in how solute-solute and solute-solvent interactions are parametrized in these force fields. We found that even for the fully polarizable AMOEBA force field, the degree of association is considerably underestimated. Instead, a fixed point-charge approach based on the newly developed IPolQ scheme [Cerutti et al. J. Phys. Chem. 2013, 117, 2328] allows for the correct modeling of the dipeptide aggregation in aqueous solution. This result should stimulate interest in novel fitting schemes that aim to improve the description of the solvent polarization effect within both explicitly polarizable and fixed point-charge frameworks. PMID:24803868

  13. Sensitivity of collective action to uncertainty about climate tipping points

    NASA Astrophysics Data System (ADS)

    Barrett, Scott; Dannenberg, Astrid

    2014-01-01

    Despite more than two decades of diplomatic effort, concentrations of greenhouse gases continue to trend upwards, creating the risk that we may someday cross a threshold for `dangerous' climate change. Although climate thresholds are very uncertain, new research is trying to devise `early warning signals' of an approaching tipping point. This research offers a tantalizing promise: whereas collective action fails when threshold uncertainty is large, reductions in this uncertainty may bring about the behavioural change needed to avert a climate `catastrophe'. Here we present the results of an experiment, rooted in a game-theoretic model, showing that behaviour differs markedly either side of a dividing line for threshold uncertainty. On one side of the dividing line, where threshold uncertainty is relatively large, free riding proves irresistible and trust illusive, making it virtually inevitable that the tipping point will be crossed. On the other side, where threshold uncertainty is small, the incentive to coordinate is strong and trust more robust, often leading the players to avoid crossing the tipping point. Our results show that uncertainty must be reduced to this `good' side of the dividing line to stimulate the behavioural shift needed to avoid `dangerous' climate change.

  14. Unique normal forms near a degenerate elliptic fixed point in two-parametric families of area-preserving maps

    NASA Astrophysics Data System (ADS)

    Gelfreich, Vassili; Gelfreikh, Natalia

    2014-07-01

    We derive simplified normal forms for an area-preserving map in a neighbourhood of a degenerate resonant elliptic fixed point. Such fixed points appear in generic families of area-preserving maps. We also derive a simplified normal form for a generic two-parametric family. The normal forms are used to analyse bifurcations of n-periodic orbits. In particular, for n ? 6 we find regions of parameters where the normal form has ‘meandering’ invariant curves.

  15. Warm Humid Climate: Methodology to Study Air Temperature Distribution: Mobile Phones Base Stations as Viable Alternative for Fixed Points

    E-print Network

    Araujo, V.; Costa, A.; Labaki, L.

    2006-01-01

    WARM-HUMID CLIMATE: METHODOLOGY TO STUDY AIR TEMPERATURE DISTRIBUTION: MOBILE PHONES BASE STATIONS AS VIABLE ALTERNATIVE FOR FIXED POINTS Angelina Dias Leão Costa (1); Lucila Labaki (2); Virgínia Araújo (3) (1) and (2) School of Civil..., in February 2006, are presented. The fixed points were defined using 20 mobile phone base stations in the city of Natal/RN, distributed along the four administrative zones. Measurements were carried out for seven days, registering air temperature...

  16. The European Fixed point Open Ocean Observatory network (FixO3): Multidisciplinary observations from the air-sea interface to the deep seafloor

    NASA Astrophysics Data System (ADS)

    Lampitt, Richard; Cristini, Luisa; Alexiou, Sofia

    2015-04-01

    The Fixed point Open Ocean Observatory network (FixO3, http://www.fixo3.eu/ ) integrates 23 European open ocean fixed point observatories and improves access to these infrastructures for the broader community. These provide multidisciplinary observations in all parts of the oceans from the air-sea interface to the deep seafloor. Started in September 2013 with a budget of 7 Million Euros over 4 years, the project has 29 partners drawn from academia, research institutions and SME's coordinated by the National Oceanography Centre, UK. Here we present the programme's achievements in the 18 months and the activities of the 12 Work Packages which have the objectives to: • integrate and harmonise the current procedures and processes • offer free access to observatory infrastructures to those who do not have such access, and free and open data services and products • innovate and enhance the current capability for multidisciplinary in situ ocean observation Open ocean observation is a high priority for European marine and maritime activities. FixO3 provides important data and services to address the Marine Strategy Framework Directive and in support of the European Integrated Maritime Policy. FixO3 provides a strong integrated framework of open ocean facilities in the Atlantic from the Arctic to the Antarctic and throughout the Mediterranean, enabling an integrated, regional and multidisciplinary approach to understand natural and anthropogenic change in the ocean.

  17. Assessment of correct fixing rate for precise point positioning ambiguity resolution on a global scale

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohong; Li, Pan

    2013-06-01

    Ambiguity resolution (AR) for a single receiver has been a popular topic in Global Positioning System (GPS) recently. Ambiguity-resolution methods for precise point positioning (PPP) have been well documented in recent years, demonstrating that it can improve the accuracy of PPP. However, users are often concerned about the reliability of ambiguity-fixed PPP solution in practical applications. If ambiguities are fixed to wrong integers, large errors would be introduced into position estimates. In this paper, we aim to assess the correct fixing rate (CFR), i.e., number of ambiguities correctly fixing to the total number of ambiguities correctly and incorrectly fixing, for PPP user ambiguity resolution on a global scale. A practical procedure is presented to evaluate the CFR of PPP user ambiguity resolution. GPS data of the first 3 days in each month of 2010 from about 390 IGS stations are used for experiments. Firstly, we use GPS data collected from about 320 IGS stations to estimate global single-differenced (SD) wide-lane and narrow-lane satellite uncalibrated phase delays (UPDs). The quality of UPDs is evaluated. We found that wide-lane UPD estimates have a rather small standard deviation (Std) between 0.003 and 0.004 cycles while most of Std of narrow-lane estimates are from 0.01 to 0.02 cycles. Secondly, many experiments have been conducted to investigate the CFR of integer ambiguity resolution we can achieve under different conditions, including reference station density, observation session length and the ionospheric activity. The results show that the CFR of PPP can exceed 98.0 % with only 1 h of observations for most user stations. No obvious correlation between the CFR and the reference station density is found. Therefore, nearly homogeneous CFR can be achieved in PPP AR for global users. At user end, higher CFR could be achieved with longer observations. The average CFR for 30-min, 1-h, 2-h and 4-h observation is 92.3, 98.2, 99.5 and 99.7 %, respectively. In order to get acceptable CFR, 1 h is a recommended minimum observation time. Furthermore, the CFR of PPP can be affected by diurnal variation and geomagnetic latitude variation in the ionosphere. During one day at the hours when rapid ionospheric variations occur or in low geomagnetic latitude regions where equatorial electron density irregularities are produced relatively frequently, a significant degradation of the CFR is demonstrated.

  18. Corrective Action Plan for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada

    Microsoft Academic Search

    K. B. Campbell

    2002-01-01

    This Corrective Action Plan (CAP) provides selected corrective action alternatives and proposes the closure methodology for Corrective Action Unit (CAU) 262, Area 25 Septic Systems and Underground Discharge Point. CAU 262 is identified in the Federal Facility Agreement and Consent Order (FFACO) of 1996. Remediation of CAU 262 is required under the FFACO. CAU 262 is located in Area 25

  19. Development and investigation of WC-C fixed-point cells

    NASA Astrophysics Data System (ADS)

    Khlevnoy, B. B.; Grigoryeva, I. A.; Otryaskin, D. A.

    2012-04-01

    Three cells of the WC-C peritectic fixed point with a temperature of about 3021 K were built and investigated. Two different sources of tungsten with nominal purities of 5N and 3N were used, and two different filling techniques were applied. There was no difference in plateau shapes between the cells. The 3N purity cell showed a small difference (0.22 K) in the melting temperature from the 5N cell, which indicates significant purification of initially contaminated tungsten. The typical melting range and repeatability of the observed peritectic melting plateaux were 100 mK and 15 mK, respectively. The melting point was stable and reproducible within 25 mK per two weeks. T90 temperature of the WC-C melting point was found to be (2747.6 ± 1.1) °C (k = 2). The observed freezing plateaux were flat and repeatable within 50 mK and 15 mK, respectively. The WC1-x-WC eutectic transition showed a melting temperature about 29 K lower than the peritectic one with a repeatability of about 0.2 K. The problem of deep supercooling is discussed and a method for its solution is shown and tested.

  20. Crustal deformation measurements in central Japan determined by a Global Positioning System fixed-point network

    NASA Technical Reports Server (NTRS)

    Shimada, Seiichi; Bock, Yehuda

    1992-01-01

    Results are presented from temporally dense measurements of crustal deformation associated with the convergence of the Eurasian (EUR), Pacific, North American, and Philippine Sea (PHS) plates, carried out in April 1988 by a 10-station GPS fixed-point network established in central Japan. Using regional orbit relaxation methods, the analysis of the first 17-month data revealed significant horizontal deformation across the Suruga trough. Namely, it was found that a site in the northern tip of PHS plate moved nearly westward with a velocity of 28 +/-5 mm per year, and a site at the southeastern tip of EUR plate moved south-southwestward with a velocity of 18 +/-5 mm per year. A significant vertical uplift with a velocity of 20 mm/yr was detected at a site inland of the Tokai district located in the Akaishi uplift zone and at a site on the Hatsushima Island in Sagami Bay.

  1. Holographic non-relativistic fermionic fixed point by the charged dilatonic black hole

    E-print Network

    Wei-Jia Li; Rene Meyer; Hongbao Zhang

    2012-01-31

    Driven by the landscape of garden-variety condensed matter systems, we have investigated how the dual spectral function behaves at the non-relativistic as well as relativistic fermionic fixed point by considering the probe Dirac fermion in an extremal charged dilatonic black hole with zero entropy. Although the pattern for both of the appearance of flat band and emergence of Fermi surface is qualitatively similar to that given by the probe fermion in the extremal Reissner-Nordstrom AdS black hole, we find a distinctly different low energy behavior around the Fermi surface, which can be traced back to the different near horizon geometry. In particular, with the peculiar near horizon geometry of our extremal charged dilatonic black hole, the low energy behavior exhibits the universal linear dispersion relation and scaling property, where the former indicates that the dual liquid is a Fermi one while the latter implies that the dual liquid is not exactly of Landau Fermi type.

  2. An experimental verification of saturated salt solution-based humidity fixed points

    NASA Astrophysics Data System (ADS)

    Carotenuto, A.; Dell'Isola, M.

    1996-11-01

    The high instability and hysterisis of the relative humidity sensors currently available on the market render necessary simple and economic calibration methodologies that can be used as a secondary of working standards. The chemical equilibrium-type systems based on saturated aqueous salt solutions, even though simple and economical, are not always metrologically satisfactory for calibration. They can, in fact, be unreliable, when some fundamental requirements are neglected: also, unacceptable discrepancies continue to exist in the equilibrium relative humidity reference data of saturated aqueous salt solutions furnished by both literature and standards. To highlight the factors that increase the reliability of calibrations with saturated aqueous salt solutions, the authors of this paper have redetermined the equilibrium relative humidity reference data of 11 saturated aqueous salt solutions at ambient pressure and temperature. The solutions chosen were the ones generally used as fixed points to obtain a relative humidity calibration scale.

  3. A fast multi-level method for the fixed point form of matrix H-equations

    SciTech Connect

    Kelley, C.T. (North Carolina State Univ., Raleigh (United States)); Northrup, J.I. (Colby College, Waterville, ME (United States))

    1993-01-01

    In previous work quasi-Newton and multi-level algorithms for fully nonlinear integral equations were designed and analyzed. The motivating examples for that work were analogs of the Chandrasekhar H-equation for matrix-valued functions. A weakness of these algorithms was that transfer between grids was done with a piecewise linear interpolation instead of Nystroem interpolation. This choice of interpolation was used because the nonlinearity in the Chandrasekhar equation was expressed in the quadratic form for which a matrix inversion is not required. In this paper the fixed point formulation is reconsidered and a conditioning issue associated with the matrix is resolved. This allows use of Nystroem interpolation and thereby a more efficient multi-level method. Implementation details on the Alliant FX series of multiprocessor computers is also discussed. 18 refs., 3 tabs.

  4. Adaptive Control for Buck Power Converter Using Fixed Point Inducting Control and Zero Average Dynamics Strategies

    NASA Astrophysics Data System (ADS)

    Hoyos Velasco, Fredy Edimer; García, Nicolás Toro; Garcés Gómez, Yeison Alberto

    In this paper, the output voltage of a buck power converter is controlled by means of a quasi-sliding scheme. The Fixed Point Inducting Control (FPIC) technique is used for the control design, based on the Zero Average Dynamics (ZAD) strategy, including load estimation by means of the Least Mean Squares (LMS) method. The control scheme is tested in a Rapid Control Prototyping (RCP) system based on Digital Signal Processing (DSP) for dSPACE platform. The closed loop system shows adequate performance. The experimental and simulation results match. The main contribution of this paper is to introduce the load estimator by means of LMS, to make ZAD and FPIC control feasible in load variation conditions. In addition, comparison results for controlled buck converter with SMC, PID and ZAD-FPIC control techniques are shown.

  5. Stability of 3D Cubic Fixed Point in Two-Coupling-Constant ?^4-Theory

    E-print Network

    H. Kleinert; S. Thoms; V. Schulte-Frohlinde

    1996-11-27

    For an anisotropic euclidean $\\phi^4$-theory with two interactions $[u (\\sum_{i=1^M {\\phi}_i^2)^2+v \\sum_{i=1}^M \\phi_i^4]$ the $\\beta$-functions are calculated from five-loop perturbation expansions in $d=4-\\varepsilon$ dimensions, using the knowledge of the large-order behavior and Borel transformations. For $\\varepsilon=1$, an infrared stable cubic fixed point for $M \\geq 3$ is found, implying that the critical exponents in the magnetic phase transition of real crystals are of the cubic universality class. There were previous indications of the stability based either on lower-loop expansions or on less reliable Pad\\'{e approximations, but only the evidence presented in this work seems to be sufficently convincing to draw this conclusion.

  6. Stability analysis for stochastic Volterra-Levin equations with Poisson jumps: Fixed point approach

    NASA Astrophysics Data System (ADS)

    Guo, Lifang; Zhu, Quanxin

    2011-04-01

    This paper is devoted to investigate a class of stochastic Volterra-Levin equations with Poisson jumps. To the best of the authors' knowledge, till now, the stability problem for this class of new systems has not yet been solved since Poisson jumps are considered. The main objective of this paper is to fill the gap. By using the fixed point theory, we first study the existence and uniqueness of the solution as well as the pth moment exponential stability for the considered system. Then based on the well known Borel-Cantelli lemma, we prove that the solution is almost surely pth moment exponentially stable. Our results improve and generalize those given in the previous literature. Finally, two simple examples are provided to illustrate the effectiveness of the obtained results.

  7. Density equalized map projections: a method for analysing clustering around a fixed point.

    PubMed

    Schulman, J; Selvin, S; Merrill, D W

    1988-04-01

    Cases plotted on a geopolitical map entail difficulties in interpretation and analysis because of variable population density in the study area. Density equalized map projections (DEMPs) eliminate the distribution of the resident population as an interfering influence by transforming map area to be proportional to population. This paper discusses a transformation algorithm, its properties, and develops statistical methods to detect clustering of cases around a fixed point for data plotted on DEMPs. We suggest two numeric methods where exact solutions are too complicated or do not exist. Finally, we illustrate these methods using data from Denver and Jefferson counties in Colorado to investigate whether lung cancer and leukaemia incidence patterns are associated with plutonium exposure from the Rocky Flats plant site. PMID:3368676

  8. Progress report for the CCT-WG5 high temperature fixed point research plan

    SciTech Connect

    Machin, G.; Woolliams, E. R. [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex,TW11 0LW (United Kingdom)] [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex,TW11 0LW (United Kingdom); Anhalt, K. [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin (Germany)] [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin (Germany); Bloembergen, P. [National Institute of Metrology (NIM), Bei San Huan Dong Lu No. 18, Beijing, 100013 (China)] [National Institute of Metrology (NIM), Bei San Huan Dong Lu No. 18, Beijing, 100013 (China); Sadli, M. [Laboratoire Commun de Métrologie (LNE-Cnam), 61, rue du Landy, 93210 Saint-Denis, La Plaine (France)] [Laboratoire Commun de Métrologie (LNE-Cnam), 61, rue du Landy, 93210 Saint-Denis, La Plaine (France); Yamada, Y. [National Measurement Institute of Japan (NMIJ), AIST, Tsukuba, Ibaraki (Japan)] [National Measurement Institute of Japan (NMIJ), AIST, Tsukuba, Ibaraki (Japan)

    2013-09-11

    An overview of the progress in High Temperature Fixed Point (HTFP) research conducted under the auspices of the CCT-WG5 research plan is reported. In brief highlights are: Provisional long term stability of HTFPs has been demonstrated. Optimum construction methods for HTFPs have been established and high quality HTFPs of Co-C, Pt-C and Re-C have been constructed for thermodynamic temperature assignment. The major sources of uncertainty in the assignment of thermodynamic temperature have been identified and quantified. The status of absolute radiometric temperature measurement has been quantified through the circulation of a set of HTFPs. The measurement campaign to assign low uncertainty thermodynamic temperatures to a selected set of HTFPs will begin in mid-2012. It is envisaged that this will be complete by 2015 leading to HTFPs becoming routine reference standards for radiometry and high temperature metrology.

  9. Ceng et al. Fixed Point Theory and Applications 2012, 2012:117 http://www.fixedpointtheoryandapplications.com/content/2012/1/117

    E-print Network

    Wong, Ngai-Ching

    Ceng et al. Fixed Point Theory and Applications 2012, 2012:117 http. #12;Ceng et al. Fixed Point Theory and Applications 2012, 2012:117 Page 2 of 21 http the hybrid viscosity approximation method for finding a common fixed point of an infinite family

  10. Fixed-point structure of low-dimensional relativistic fermion field theories: Universality classes and emergent symmetry

    E-print Network

    Gehring, Friedrich; Janssen, Lukas

    2015-01-01

    We investigate a class of relativistic fermion theories in 2unified framework. Within the limit of pointlike interactions, the RG flow of couplings reveals a network of interacting fixed points, each of which defines a universality class. A subset of fixed points are "critical fixed points" with one RG relevant direction being candidates for critical points of second-order phase transitions. Identifying invariant hyperplanes of the RG flow and classifying their attractive/repulsive properties, we find evidence for emergent higher chiral symmetries as a function of Nf. For the case of the Thirring model, we discover a new critical flavor number that separates the RG stable large-Nf regime from an intermediate-Nf regime in which symmetry-breaking perturbations become RG relevant. This new critical flavor number has to be distinguished from the ...

  11. HOMOCLINIC POINTS OF ALGEBRAIC Zd-ACTIONS DOUGLAS LIND AND KLAUS SCHMIDT

    E-print Network

    Lind, Douglas A.

    specification properties for such actions. This provides an extensive class of examples of Zd-actions HOMOCLINIC POINTS OF ALGEBRAIC Zd-ACTIONS DOUGLAS LIND AND KLAUS SCHMIDT Abstract. Let ff be an action of Zd by continuous automorphisms of a compact abelian group X

  12. Conformal sector of quantum Einstein gravity in the local potential approximation: Non-Gaussian fixed point and a phase of unbroken diffeomorphism invariance

    SciTech Connect

    Reuter, M.; Weyer, H. [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany)

    2009-07-15

    We explore the nonperturbative renormalization group flow of quantum Einstein gravity (QEG) on an infinite dimensional theory space. We consider 'conformally reduced' gravity where only fluctuations of the conformal factor are quantized and employ the local potential approximation for its effective average action. The requirement of 'background independence' in quantum gravity entails a partial differential equation governing the scale dependence of the potential for the conformal factor which differs significantly from that of a scalar matter field. In the infinite dimensional space of potential functions we find a Gaussian as well as a non-Gaussian fixed point which provides further evidence for the viability of the asymptotic safety scenario. The analog of the invariant cubic in the curvature which spoils perturbative renormalizability is seen to be unproblematic for the asymptotic safety of the conformally reduced theory. The scaling fields and dimensions of both fixed points are obtained explicitly and possible implications for the predictivity of the theory are discussed. Spacetime manifolds with R{sup d} as well as S{sup d} topology are considered. Solving the flow equation for the potential numerically we obtain examples of renormalization group trajectories inside the ultraviolet critical surface of the non-Gaussian fixed point. The quantum theories based upon some of them show a phase transition from the familiar (low energy) phase of gravity with spontaneously broken diffeomorphism invariance to a new phase of unbroken diffeomorphism invariance; the latter phase is characterized by a vanishing expectation value of the metric.

  13. Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Meng, Xiaolin; Dodson, Alan H.; Ge, Maorong; Teferle, Felix N.

    2010-12-01

    Integer ambiguity resolution at a single receiver can be achieved if the fractional-cycle biases are separated from the ambiguity estimates in precise point positioning (PPP). Despite the improved positioning accuracy by such integer resolution, the convergence to an ambiguity-fixed solution normally requires a few tens of minutes. Even worse, these convergences can repeatedly occur on the occasion of loss of tracking locks for many satellites if an open sky-view is not constantly available, consequently totally destroying the practicability of real-time PPP. In this study, in case of such re-convergences, we develop a method in which ionospheric delays are precisely predicted to significantly accelerate the integer ambiguity resolution. The effectiveness of this method consists in two aspects: first, wide-lane ambiguities can be rapidly resolved using the ionosphere-corrected wide-lane measurements, instead of the noisy Melbourne-Wübbena combination measurements; second, narrow-lane ambiguity resolution can be accelerated under the tight constraints derived from the ionosphere-corrected unambiguous wide-lane measurements. In the test at 90 static stations suffering from simulated total loss of tracking locks, 93.3 and 95.0% of re-convergences to wide-lane and narrow-lane ambiguity resolutions can be achieved within five epochs of 1-Hz measurements, respectively, even though the time latency for the predicted ionospheric delays is up to 180 s. In the test at a mobile van moving in a GPS-adverse environment where satellite number significantly decreases and cycle slips frequently occur, only when the predicted ionospheric delays are applied can the rate of ambiguity-fixed epochs be dramatically improved from 7.7 to 93.6% of all epochs. Therefore, this method can potentially relieve the unrealistic requirement of a continuous open sky-view by most PPP applications and improve the practicability of real-time PPP.

  14. New Approach in Filling of Fixed-Point Cells: Case Study of the Melting Point of Gallium

    NASA Astrophysics Data System (ADS)

    Bojkovski, J.; Hiti, M.; Batagelj, V.; Drnovšek, J.

    2008-02-01

    The typical way of constructing fixed-point cells is very well described in the literature. The crucible is loaded with shot, or any other shape of pure metal, inside an argon-filled glove box. Then, the crucible is carefully slid into a fused-silica tube that is closed at the top with an appropriate cap. After that, the cell is removed from the argon glove box and melted inside a furnace while under vacuum or filled with an inert gas like argon. Since the metal comes as shot, or in some other shape such as rods of various sizes, and takes more volume than the melted material, it is necessary to repeat the procedure until a sufficient amount of material is introduced into the crucible. With such a procedure, there is the possibility of introducing additional impurities into the pure metal with each cycle of melting the material and putting it back into the glove box to fill the cell. Our new approach includes the use of a special, so-called dry-box system, which is well known in chemistry. The atmosphere inside the dry box contains less than 20 ppm of water and less than 3 ppm of oxygen. Also, the size of the dry box allows it to contain a furnace for melting materials, not only for gallium but for higher-temperature materials as well. With such an approach, the cell and all its parts (pure metal, graphite, fused-silica tube, and cap) are constantly inside the controlled atmosphere, even while melting the material and filling the crucible. With such a method, the possibility of contaminating the cell during the filling process is minimized.

  15. Realization of the WC-C peritectic fixed point at NIM and NMIJ

    SciTech Connect

    Wang, T.; Bai, C.; Yuan, Z.; Dong, W.; Lu, X. [National Institute of Metrology (NIM), Beijing (China)] [National Institute of Metrology (NIM), Beijing (China); Sasajima, N.; Yamada, Y.; Ara, C. [National Metrology Institute of Japan, AIST (NMIJ, AIST), Tsukuba (Japan)] [National Metrology Institute of Japan, AIST (NMIJ, AIST), Tsukuba (Japan)

    2013-09-11

    Three WC-C peritectic fixed point cells, constructed from different sources of tungsten with different nominal purities, were measured at NIM and NMIJ. The three cells were constructed at NMIJ by NIM and NMIJ staffs, and T{sub 90} values of the three cells were measured at NMIJ during the period 31 Aug. to 25 Dec. 2009. Thereafter, the three cells were then transported to NIM, and T{sub 90} values of these cells were measured from 7 Dec. 2011 to 9 Jan. 2012. The results showed that T{sub 90} values of the three cells measured at the two institutes agreed within 0.4 °C with the combined scale comparison uncertainty of 1.7 °C (k= 2). The main component of the uncertainty is not the uncertainty due to impurities of the cells but the scale uncertainty and the stability of the measurement system. From these results it can be concluded that the WC-C cell is stable enough to provide new means of international high-temperature scale comparison above 3000 K.

  16. 3D transient fixed point mesh adaptation for time-dependent problems: Application to CFD simulations

    NASA Astrophysics Data System (ADS)

    Alauzet, F.; Frey, P. J.; George, P. L.; Mohammadi, B.

    2007-03-01

    This paper deals with the adaptation of unstructured meshes in three dimensions for transient problems with an emphasis on CFD simulations. The classical mesh adaptation scheme appears inappropriate when dealing with such problems. Hence, another approach based on a new mesh adaptation algorithm and a metric intersection in time procedure, suitable for capturing and track such phenomena, is proposed. More precisely, the classical approach is generalized by inserting a new specific loop in the main adaptation loop in order to solve a transient fixed point problem for the mesh-solution couple. To perform the anisotropic metric intersection operation, we apply the simultaneous reduction of the corresponding quadratic form. Regarding the adaptation scheme, an anisotropic geometric error estimate based on a bound of the interpolation error is proposed. The resulting computational metric is then defined using the Hessian of the solution. The mesh adaptation stage (surface and volume) is based on the generation, by global remeshing, of a unit mesh with respect to the prescribed metric. A 2D model problem is used to illustrate the difficulties encountered. Then, 2D and 3D complexes and representative examples are presented to demonstrate the efficiency of this method.

  17. Resource and Performance Evaluations of Fixed Point QRD-RLS Systolic Array through FPGA Implementation

    NASA Astrophysics Data System (ADS)

    Yokoyama, Yoshiaki; Kim, Minseok; Arai, Hiroyuki

    At present, when using space-time processing techniques with multiple antennas for mobile radio communication, real-time weight adaptation is necessary. Due to the progress of integrated circuit technology, dedicated processor implementation with ASIC or FPGA can be employed to implement various wireless applications. This paper presents a resource and performance evaluation of the QRD-RLS systolic array processor based on fixed-point CORDIC algorithm with FPGA. In this paper, to save hardware resources, we propose the shared architecture of a complex CORDIC processor. The required precision of internal calculation, the circuit area for the number of antenna elements and wordlength, and the processing speed will be evaluated. The resource estimation provides a possible processor configuration with a current FPGA on the market. Computer simulations assuming a fading channel will show a fast convergence property with a finite number of training symbols. The proposed architecture has also been implemented and its operation was verified by beamforming evaluation through a radio propagation experiment.

  18. Fixed-point Algorithms for Constrained ICA and their Applications in fMRI Data Analysis

    PubMed Central

    Wang, Ze

    2011-01-01

    Constrained independent component analysis (CICA) eliminates the order ambiguity of standard ICA by incorporating prior information into the learning process to sort the components intrinsically. However, the original CICA (OCICA) and its variants depend on a learning rate, which is not easy to be tuned for various applications. To solve this problem, two learning-rate free CICA algorithms were derived in this paper using the fixed-point learning concept. A complete stability analysis was provided for the proposed methods, which also made a correction to the stability analysis given to OCICA. Variations for adding constraints either to the components or the associated time courses were derived too. Using synthetic data, the proposed methods yielded a better stability and a better source separation quality in terms of higher SNR and smaller performance index (PI) than OCICA. For the artificially generated brain activations, the new CICAs demonstrated a better sensitivity/specificity performance than standard univariate general linear model (GLM) and standard ICA. OCICA showed a similar sensitivity/specficity gain but failed to converge for several times. Using fMRI data acquired with a well-characterized sensorimotor task, the proposed CICAs yielded better sensitivity than OCICA, standard ICA, and GLM in all the target functional regions in terms of either higher t-values or larger suprathreshold cluster extensions using the same significance threshold. In addition, they were more stable than OCICA and standard ICA for analyzing the sensorimotor fMRI data. PMID:21908126

  19. Realization of the WC-C peritectic fixed point at NIM and NMIJ

    NASA Astrophysics Data System (ADS)

    Wang, T.; Sasajima, N.; Yamada, Y.; Bai, C.; Yuan, Z.; Dong, W.; Ara, C.; Lu, X.

    2013-09-01

    Three WC-C peritectic fixed point cells, constructed from different sources of tungsten with different nominal purities, were measured at NIM and NMIJ. The three cells were constructed at NMIJ by NIM and NMIJ staffs, and T90 values of the three cells were measured at NMIJ during the period 31 Aug. to 25 Dec. 2009. Thereafter, the three cells were then transported to NIM, and T90 values of these cells were measured from 7 Dec. 2011 to 9 Jan. 2012. The results showed that T90 values of the three cells measured at the two institutes agreed within 0.4 °C with the combined scale comparison uncertainty of 1.7 °C (k = 2). The main component of the uncertainty is not the uncertainty due to impurities of the cells but the scale uncertainty and the stability of the measurement system. From these results it can be concluded that the WC-C cell is stable enough to provide new means of international high-temperature scale comparison above 3000 K.

  20. General fixed points of quasi-local frustration-free quantum semigroups: from invariance to stabilization

    E-print Network

    Peter D. Johnson; Francesco Ticozzi; Lorenza Viola

    2015-06-25

    We investigate under which conditions a general mixed state on a finite-dimensional multipartite quantum system may be the unique, globally stable fixed point of frustration-free semigroup dynamics subject to specified quasi-locality constraints. Our central result is a linear-algebraic necessary and sufficient condition for a generic (full-rank) target state to be frustration-free quasi-locally stabilizable, along with an explicit procedure for constructing Markovian dynamics that achieve stabilization. If the target state is not full-rank, we establish sufficiency under an additional condition, which is naturally motivated by consistency with pure-state stabilization results yet provably not necessary in general. Several applications of our formalism are discussed, of relevance to both dissipative quantum engineering and non-equilibrium quantum statistical mechanics. In particular, we show that a large class of graph product states (including arbitrary thermal graph states) as well as Gibbs states of commuting Hamiltonians are frustration-free quasi-locally stabilizable relative to natural quasi-locality constraints. In addition, we explicitly demonstrate how stabilization may still be achieved, including for target states exhibiting non-trivial multipartite entanglement, despite the lack of an underlying commuting structure, albeit scalability to arbitrary system size remains in this case an open question.

  1. Universal self-similar dynamics of relativistic and nonrelativistic field theories near nonthermal fixed points

    E-print Network

    A. Pineiro Orioli; K. Boguslavski; J. Berges

    2015-03-09

    We investigate universal behavior of isolated many-body systems far from equilibrium, which is relevant for a wide range of applications from ultracold quantum gases to high-energy particle physics. The universality is based on the existence of nonthermal fixed points, which represent nonequilibrium attractor solutions with self-similar scaling behavior. The corresponding dynamic universality classes turn out to be remarkably large, encompassing both relativistic as well as nonrelativistic quantum and classical systems. For the examples of nonrelativistic (Gross-Pitaevskii) and relativistic scalar field theory with quartic self-interactions, we demonstrate that infrared scaling exponents as well as scaling functions agree. We perform two independent nonperturbative calculations, first by using classical-statistical lattice simulation techniques and second by applying a vertex-resummed kinetic theory. The latter extends kinetic descriptions to the nonperturbative regime of overoccupied modes. Our results open new perspectives to learn from experiments with cold atoms aspects about the dynamics during the early stages of our universe.

  2. Overcoming the Limitations of the SIE and OME Methods in Assessing the Effects of Impurities in Temperature Fixed Points

    NASA Astrophysics Data System (ADS)

    Fahr, M.; Cundy, D. S.

    2015-03-01

    Impurities are still among the primary concerns regarding the realization of many fixed points of the International Temperature Scale (ITS-90). Several methods have been suggested to correct for these effects. The most promising strategy, with regard to the achievable uncertainty level, is the `sum of the individual estimates' (SIE) method. It involves a chemical analysis of the material and a calculation of each of the detected chemical species' effect on the phase-transition temperature of the fixed-point substance. This correction can be accurate only if all the detected impurities are completely dissolved. Given the recent evidence for insoluble impurities in metal fixed points, this strategy needs to be modified; otherwise, it may lead to an inaccurate estimation of the impurity-related effect on the fixed-point temperature. In this article, a correction method is set out that reflects the crucial distinction between soluble, insoluble, and partially soluble impurities. This `sum of the individual estimates for the dissolved species' (SIEDS) method starts from a chemical analysis but takes into account only the dissolved particles. For this purpose, different types of substances are considered as possible dissolved impurities and are discussed from a chemical point of view. For those impurities where data are insufficient, only an uncertainty estimation is possible. For this purpose, the `overall maximum estimate of the dissolved species' (OMEDS) method is derived from the SIEDS method as the new counterpart to the well-known `overall maximum estimate' (OME) method.

  3. Group Action Recognition Using Space-Time Interest Points

    E-print Network

    Ling, Haibin

    in computer vision due to the large complexity induced by multiple motion patterns. This paper aims the number of people in the group action. our purpose is to distinguish the group actions, just as basketball. In fact, the system has a linear time complexity, given previously extracted features. The rest

  4. The H2O (I) - H2O (III) - H2O (L) Triple Point of Water as a Fixed Pressure Point

    Microsoft Academic Search

    N. Bignell; V. E. Bean

    1988-01-01

    An apparatus to utilize the H2O (I) - H2O (III) - H2O (L) triple point as a pressure fixed point is described. A technique to establish the three phases simultaneously in the cell is described. The value of the pressure was measured with a piston gage and was found to be (208.829 +\\/- 0.025) MPa at the 99.7 percent confidence

  5. A Floating-point Coprocessor Configured by a FPGA in a Digital Platform Based on Fixed-point DSP for Power Electronics

    Microsoft Academic Search

    Haibing Hu; Tianjun Jin; Xianmiao Zhang; Zhengyu Lu; Zhaoming Qian

    2006-01-01

    A configurable floating-point coprocessor by a FPGA is designed to enhance the computational capability of the digital platform based on the fixed-point DSP, with which the platform will be competent to implement intensively computational tasks. Detailed design procedures of the coprocessor are presented. A new division algorithm is proposed by combining the lookup-table algorithm and multiplicative algorithm in order to

  6. A simple fixed-point approach to invert a deformation field.

    PubMed

    Chen, Mingli; Lu, Weiguo; Chen, Quan; Ruchala, Kenneth J; Olivera, Gustavo H

    2008-01-01

    Inversion of deformation fields is applied frequently to map images, dose, and contours between the reference frame and the study frame. A prevailing approach that takes the negative of the forward deformation as the inverse deformation is oversimplified and can cause large errors for large deformations or deformations that are composites of several deformations. Other approaches, including Newton's method and scatter data interpolation, either require the first derivative or are very inefficient. Here we propose an iterative approach that is easy to implement, converges quickly to the inverse when it does, and works for a majority of cases in practice. Our approach is rooted in fixed-point theory. We build a sequence to approximate the inverse deformation through iterative evaluation of the forward deformation. A sufficient but not necessary convergence condition (Lipschitz condition) and its proof are also given. Though this condition guarantees the convergence, it may not be met for an arbitrary deformation field. One should always check whether the inverse exists for the given forward deformation field by calculating its Jacobian. If nonpositive values of the Jacobian occur only for few voxels, this method will usually converge to a pseudoinverse. In case the iteration fails to converge, one should switch to other means of finding the inverse. We tested the proposed method on simulated 2D data and real 3D computed tomography data of a lung patient and compared our method with two implementations in the Insight Segmentation and Registration Toolkit (ITK). Typically less than ten iterations are needed for our method to get an inverse deformation field with clinically relevant accuracy. Based on the test results, our method is about ten times faster and yet ten times more accurate than ITK's iterative method for the same number of iterations. Simulations and real data tests demonstrated the efficacy and the accuracy of the proposed algorithm. PMID:18293565

  7. My research area is the part of algebraic topology that is included within topological fixed point theory, a broad subject that has substantial interactions

    E-print Network

    Brown, Robert F.

    as with other parts of topology. Fixed point theory is the study of solutions to the equation f(x) = x for a map-valued map f means that x belongs to the set f(x). The general fixed point theory of such functions is a big of the Handbook of Topological Fixed Point Theory (Springer, 2005, pages 440 - 444). My research concerned n

  8. Crustal deformation measurements in Central Japan determined by a global positioning system fixed-point network

    NASA Astrophysics Data System (ADS)

    Bock, Yehuda

    1992-08-01

    A Global Positioning System (GPS) fixed-point network has been operating in the Kanto and Tokai districts of central Japan since April 1988 to detect crustal deformation associated with the convergence of the Eurasian. Pacific, North American, and Philippine Sea plates and to monitor the deformation cycles of frequent large interplate and intraplate earthquakes. This 10-station network established by the National Research Institute for Earth Science and Disaster Prevention (NIED) is the first continuously monitoring network of its kind. We determine deformation within the network using two consecutive days of data every 2 weeks for the first 17 months of operations. We use a station and orbit relaxation method which relies exclusively on data collected within the NIED network, except for 1 week of global GPS tracking data which is used to determine initial station positions with respect to the global refrence frame. We detect, relative to a station on the Eurasian plate in central Japan, significant westward motion of 28 mm/yr of the northern tip of the Philippine Sea plate, which is subducting beneath the Eurasian plate at the Suruga trough. Our results support finite element models of collision of the Izu Block with the Eruasian plate based on earthquake focal mechanisms and plate block motions of the Japanese archipelago determined from conventional geodetic measurements over the last century. We detect southwestward motion of 18 mm/yr of the southeastern tip of the Eurasian plate, confirming expected surface extension of the subducted plate parallel to the Suruga trough axis. Significant vertical uplift with a velocity of 20 mm/yr is suggested at a sites inland of the Tokai district located in the Akaishi uplift zone and at a site on Hatsushima Island in Sagami Bay. The general tendency of vertical movements of the other site agrees with vertical velocities obtained from 70 years of geodetic leveling and with Quaternary vertical displacements determined from geomorphological and other geological evidence. We detect no significant crustal motion across the Fossa Magna tectonic zone in central Japan (often considered a plate boundary), across the Tokyo metropolitan area, nor across the Sagami trough associated with the subduction of the Philippine Sea plate beneath northeast Japan. Our results demonstrate the power of regionally based, continuously monitoring GPS networks for obtaining temporally dense meausrements of small horizontal and vertical crustal movements across plate boundary zones.

  9. Fixed-point structure of low-dimensional relativistic fermion field theories: Universality classes and emergent symmetry

    E-print Network

    Friedrich Gehring; Holger Gies; Lukas Janssen

    2015-06-24

    We investigate a class of relativistic fermion theories in 2unified framework. Within the limit of pointlike interactions, the RG flow of couplings reveals a network of interacting fixed points, each of which defines a universality class. A subset of fixed points are "critical fixed points" with one RG relevant direction being candidates for critical points of second-order phase transitions. Identifying invariant hyperplanes of the RG flow and classifying their attractive/repulsive properties, we find evidence for emergent higher chiral symmetries as a function of Nf. For the case of the Thirring model, we discover a new critical flavor number that separates the RG stable large-Nf regime from an intermediate-Nf regime in which symmetry-breaking perturbations become RG relevant. This new critical flavor number has to be distinguished from the chiral-critical flavor number, below which the Thirring model is expected to allow spontaneous chiral symmetry breaking, and its existence offers a resolution to the discrepancy between previous results obtained in the continuum and the lattice Thirring models. Moreover, we find indications for a new feature of universality: details of the critical behavior can depend on additional "spectator symmetries" that remain intact across the phase transition. Implications for the physics of interacting fermions on the honeycomb lattice, for which our theory space provides a simple model, are given.

  10. Large-N Wilsonian beta function in SU(N) Yang-Mills theory by localization on the fixed points of a semigroup contracting the functional measure

    E-print Network

    Marco Bochicchio

    2011-02-21

    In a certain (non-commutative) version of large-N SU(N) Yang-Mills theory there are special Wilson loops, called twistor Wilson loops for geometrical reasons, whose v.e.v. is independent on the parameter that occurs in their operator definition. There is a semigroup that acts on the parameter by rescaling and on the functional measure, resolved into anti-selfdual orbits by a non-supersymmetric version of the Nicolai map, by contracting the support of the measure. As a consequence the twistor Wilson loops are localized on the fixed points of the semigroup of contractions. This localization is a non-supersymmetric analogue of the localization that occurs in the Nekrasov partition function of the n=2 SUSY YM theory on the fixed points of a certain torus action on the moduli space of (non-commutative) instantons. One main consequence of the localization in the large-N YM case, as in the n=2 SUSY YM case, is that the beta function of the Wilsonian coupling constant in the anti-selfdual variables is one-loop exact. Consequently the large-N Yang-Mills canonical beta function has a NSVZ form that reproduces the first two universal perturbative coefficients.

  11. Formalin Fixed Paraffin Embedded Tissue as a Starting Point for PrPSc Detection by ELISA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Formalin fixed paraffin embedded tissue are regularly employed in TSE diagnosis by IHC, the standard by which all other diagnostic protocols are currently judged. While IHC affords advantages over diagnostic approaches that typically utilize fresh or frozen tissue, such as Western blot...

  12. Properties of the non-Gaussian fixed point in 4D compact U(1) lattice gauge theory

    E-print Network

    J. Cox; W. Franzki; J. Jersak; C. B. Lang; T. Neuhaus; P. Stephenson

    1996-08-20

    We examine selected properties of the gauge-ball spectrum and fermionic variables in the vicinity of the recently discussed non-Gaussian fixed point of 4D compact U(1) lattice gauge theory within the quenched approximation. Approaching the critical point from within the confinement phase, our data support scaling of $T1^{+-}$ gauge-ball states in units of the string tension square root. The analysis of the chiral condensate within the framework of a scaling form for the equation of state suggests non mean-field values for the magnetic exponents $\\delta$ and $\\beta_{exp}$.

  13. Derivation of the Fixed-Points Theory with Some Numerical Simulations for Global Vibration Control of Structure with Closely Spaced Natural Frequencies

    Microsoft Academic Search

    Jedol Dayou; Semyung Wang

    2006-01-01

    The fixed-points theory has been used as one of the design laws in fabricating a vibration neutralizer for the control of a relatively simple structure. The underlying principle of the theory is that in the frequency response function (FRF) of the system considered, there exist two fixed points that are common to all FRF curves regardless of the damping value

  14. Fixed point action and topological charge for SU(2) gauge theory

    E-print Network

    Thomas A. DeGrand; Anna Hasenfratz; Decai Zhu

    1996-07-30

    We present a theoretically consistent definition of the topological charge operator based on renormalization group arguments. Results of the measurement of the topological susceptibility at zero and finite temperature for SU(2) gauge theory are presented.

  15. Two-stage fixed-bed gasifier with selectable middle gas off-take point

    DOEpatents

    Strickland, Larry D. (Morgantown, WV); Bissett, Larry A. (Morgantown, WV)

    1992-01-01

    A two-stage fixed bed coal gasifier wherein an annular region is in registry with a gasification zone underlying a devolatilization zone for extracting a side stream of high temperature substantially tar-free gas from the gasifier. A vertically displaceable skirt means is positioned within the gasifier to define the lower portion of the annular region so that vertical displacement of the skirt means positions the inlet into the annular region in a selected location within or in close proximity to the gasification zone for providing a positive control over the composition of the side stream gas.

  16. An accurate fixed-point 8×8 IDCT algorithm based on 2-D algebraic integer representation

    NASA Astrophysics Data System (ADS)

    Amer, Ihab; Badawy, Wael; Dimitrov, Vassil; Jullien, Graham

    2007-09-01

    This paper proposes an algorithm that is based on the application of Algebraic Integer (AI) representation of numbers on the AAN fast Inverse Discrete Cosine Transform (IDCT) algorithm. AI representation allows for maintaining an error-free representation of IDCT until the last step of each 1-D stage of the algorithm, where a reconstruction step from the AI domain to the fixed precision binary domain is required. This delay in introducing the rounding error prevents the accumulation of error throughout the calculations, which leads to the reported high-accuracy results. The proposed algorithm is simple and well suited for hardware implementation due to the absence of computationally extensive multiplications. The obtained results confirm the high accuracy of the proposed algorithm compared to other fixed-point implementations of IDCT.

  17. A Class of Boundary Value Problems Arising in Mathematical Physics: A Green's Function Fixed-point Iteration Method

    NASA Astrophysics Data System (ADS)

    Khuri, Suheil; Sayfy, Ali

    2015-05-01

    This paper presents a method based on embedding Green's function into a well-known fixed-point iteration scheme for the numerical solution of a class of boundary value problems arising in mathematical physics and geometry, in particular the Yamabe equation on a sphere. Convergence of the numerical method is exhibited and is proved via application of the contraction principle. A selected number of cases for the parameters that appear in the equation are discussed to demonstrate and confirm the applicability, efficiency, and high accuracy of the proposed strategy. The numerical outcomes show the superiority of our scheme when compared with existing numerical solutions.

  18. Computing the Least Fix-point Semantics of Denite Logic Programs Using BDDs

    Microsoft Academic Search

    Thomas Jensen; Tiphaine Turpin

    2009-01-01

    We present the semantic foundations for computing the least x-point semantics of denite logic programs using only standard operations over boolean functions. More precisely, we propose a representation of sets of rst-order terms by boolean functions and a provably sound formulation of intersection, union, and projection (an operation similar to restriction in relational databases) using conjunction, disjunction, and existential quantication.

  19. A Polynomial Time Algorithm for Counting Integral Points in Polyhedra when the Dimension Is Fixed

    Microsoft Academic Search

    Alexander I. Barvinok

    1993-01-01

    We prove that for any dimension d there exists a polynomial time algorithm for counting integral points in polyhedra in the d-dimensional Euclidean space. Previously such algorithms were known for dimensions d=1,2,3, and 4 only

  20. Corrective Action Plan for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada

    SciTech Connect

    K. B. Campbell

    2002-06-01

    This Corrective Action Plan (CAP) provides selected corrective action alternatives and proposes the closure methodology for Corrective Action Unit (CAU) 262, Area 25 Septic Systems and Underground Discharge Point. CAU 262 is identified in the Federal Facility Agreement and Consent Order (FFACO) of 1996. Remediation of CAU 262 is required under the FFACO. CAU 262 is located in Area 25 of the Nevada Test Site (NTS), approximately 100 kilometers (km) (62 miles [mi]) northwest of Las Vegas, Nevada. The nine Corrective Action Sites (CASs) within CAU 262 are located in the Nuclear Rocket Development Station complex. Individual CASs are located in the vicinity of the Reactor Maintenance, Assembly, and Disassembly (R-MAD); Engine Maintenance, Assembly, and Disassembly (E-MAD); and Test Cell C compounds. CAU 262 includes the following CASs as provided in the FFACO (1996); CAS 25-02-06, Underground Storage Tank; CAS 25-04-06, Septic Systems A and B; CAS 25-04-07, Septic System; CAS 25-05-03, Leachfield; CAS 25-05-05, Leachfield; CAS 25-05-06, Leachfield; CAS 25-05-08, Radioactive Leachfield; CAS 25-05-12, Leachfield; and CAS 25-51-01, Dry Well. Figures 2, 3, and 4 show the locations of the R-MAD, the E-MAD, and the Test Cell C CASs, respectively. The facilities within CAU 262 supported nuclear rocket reactor engine testing. Activities associated with the program were performed between 1958 and 1973. However, several other projects used the facilities after 1973. A significant quantity of radioactive and sanitary waste was produced during routine operations. Most of the radioactive waste was managed by disposal in the posted leachfields. Sanitary wastes were disposed in sanitary leachfields. Septic tanks, present at sanitary leachfields (i.e., CAS 25-02-06,2504-06 [Septic Systems A and B], 25-04-07, 25-05-05,25-05-12) allowed solids to settle out of suspension prior to entering the leachfield. Posted leachfields do not contain septic tanks. All CASs located in CAU 262 are inactive or abandoned. However, some leachfields may still receive liquids from runoff during storm events. Results from the 2000-2001 site characterization activities conducted by International Technology (IT) Corporation, Las Vegas Office are documented in the Corrective Action Investigation Report for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada. This document is located in Appendix A of the Corrective Action Decision Document for CAU 262. Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada. (DOE/NV, 2001).

  1. Mass Measurement Using the Fixed Point of a Spring-Mass System with a Dynamic Vibration Absorber

    NASA Astrophysics Data System (ADS)

    Yamamoto, Satoru; Ishino, Yuji; Takasaki, Masaya; Mizuno, Takeshi

    A vibration-type measurement system characterized by the use of an undamped dynamic vibration absorber has been developed. However, inevitable damping in the absorber may cause measurement error. A new method of measuring mass is proposed to overcome this problem. The measurement system utilizes the fixed point of a mass-spring system with a dynamic vibration absorber so that the mass is estimated regardless of damping in the absorber. A phase-looked loop (PLL) is used to achieve tuning. The principle of measurement is described on the basis of a mathematical model. A measuring apparatus was designed and fabricated, and several of its basic characteristics were studied experimentally. Damping of the primary system was found to affect fixed point formation. By reducing the damping of the primary system by a voice coil motor, the measurement conditions were achieved. The efficacy of the apparatus was studied both analytically and experimentally. The measurement conditions were realized automatically by the PLL. Mass measurement was performed while the PLL was operated; the average measurement error was within 0.21 [%].

  2. A Characterization of Cauchy Sequences in Fuzzy Metric Spaces and Its Application to Fuzzy Fixed Point Theory

    E-print Network

    Mortaza Abtahi

    2014-10-20

    We introduce the concept of fuzzy Ciric-Matkowski contractive mappings as a generalization of fuzzy Meir-Keeler type contractions. We also introduce a class $\\Psi_1$ of gauge functions $\\psi:(0,1]\\to(0,1]$ in the sense that, for any $r\\in(0,1)$, there exists $\\rho\\in(r,1)$ such that $1-r> \\tau >1-\\rho$ implies $\\psi(\\tau)\\geq 1-r$. We show that fuzzy $\\psi$-contractive mappings ($\\psi\\in\\Psi_1$) are fuzzy Ciric-Matkowski contractive mappings. Then, we present a characterization of $M$-Cauchy sequences in fuzzy metric spaces. This characterization is used to establish new fuzzy fixed point theorems. Our results include those of Mihet (Fuzzy $\\psi$-contractive mappings in non-Archimedean fuzzy metric spaces, Fuzzy Sets Syst. 159(2008) 739--744.), Wardowski (Fuzzy contractive mappings and fixed points in fuzzy metric spaces, Fuzzy Sets Syst. 222(2013) 108--114) and others. Examples are given to support the results.

  3. Higher order point and continuum mechanics from phase-space action

    Microsoft Academic Search

    J. Shamanna; B. Talukdar; U. Das

    2002-01-01

    It is pointed out that use of phase-space action provides an elegant method to study the canonical structure of problems in mechanics. Higher order Lagrangian systems are Hamiltonized by employing the variational principle in phase space. Studies are envisaged for both particle dynamics and field theory. Hamilton's equations are expressed in terms of appropriate Poisson brackets.

  4. Characterizing the size distribution of particles in urban stormwater by use of fixed-point sample-collection methods

    USGS Publications Warehouse

    Selbig, William R.; Bannerman, Roger T.

    2011-01-01

    The U.S Geological Survey, in cooperation with the Wisconsin Department of Natural Resources (WDNR) and in collaboration with the Root River Municipal Stormwater Permit Group monitored eight urban source areas representing six types of source areas in or near Madison, Wis. in an effort to improve characterization of particle-size distributions in urban stormwater by use of fixed-point sample collection methods. The types of source areas were parking lot, feeder street, collector street, arterial street, rooftop, and mixed use. This information can then be used by environmental managers and engineers when selecting the most appropriate control devices for the removal of solids from urban stormwater. Mixed-use and parking-lot study areas had the lowest median particle sizes (42 and 54 (u or mu)m, respectively), followed by the collector street study area (70 (u or mu)m). Both arterial street and institutional roof study areas had similar median particle sizes of approximately 95 (u or mu)m. Finally, the feeder street study area showed the largest median particle size of nearly 200 (u or mu)m. Median particle sizes measured as part of this study were somewhat comparable to those reported in previous studies from similar source areas. The majority of particle mass in four out of six source areas was silt and clay particles that are less than 32 (u or mu)m in size. Distributions of particles ranging from 500 (u or mu)m were highly variable both within and between source areas. Results of this study suggest substantial variability in data can inhibit the development of a single particle-size distribution that is representative of stormwater runoff generated from a single source area or land use. Continued development of improved sample collection methods, such as the depth-integrated sample arm, may reduce variability in particle-size distributions by mitigating the effect of sediment bias inherent with a fixed-point sampler.

  5. Corrective Action Investigation Plan for Corrective Action Unit 556: Dry Wells and Surface Release Points Nevada Test Site, Nevada (Draft), Revision 0

    SciTech Connect

    Grant Evenson

    2007-02-01

    Corrective Action Unit  (CAU) 556, Dry Wells and Surface Release Points, is located in Areas 6 and 25 of the Nevada Test Site, 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 556 is comprised of four corrective action sites (CASs) listed below: •06-20-04, National Cementers Dry Well •06-99-09, Birdwell Test Hole •25-60-03, E-MAD Stormwater Discharge and Piping •25-64-01, Vehicle Washdown and Drainage Pit These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document.

  6. Four-point vertices from the 2PI and 4PI effective actions

    NASA Astrophysics Data System (ADS)

    Carrington, M. E.; Fu, Wei-Jie; Mikula, P.; Pickering, D.

    2014-01-01

    We consider a symmetric scalar theory with quartic coupling in two and three dimensions and compare the self-consistent four-point vertex obtained from the four-particle-irreducible effective action with the Bethe-Salpeter 4-vertex from the two-particle-irreducible effective action. At zero external momenta the two vertices agree well with each other when the coupling strength is small, but differences between them become more and more pronounced as the coupling strength is increased. We also study the momentum dependence of the two vertices and show that for certain momentum configurations they are almost identical but differ for general momentum arguments.

  7. Optical fixing the positions of the off-shore objects applying the method of two reference points

    NASA Astrophysics Data System (ADS)

    Naus, Krzysztof; Szulc, Dariusz

    2014-06-01

    The Paper presents the optical method of fixing the off-shore objects positions from the land. The method is based on application of two reference points, having the geographical coordinates defined. The first point was situated high on the sea shore, where also the camera was installed. The second point was intended for use to determine the topocentric horizon plane and it was situated at the water-level. The first section of the Paper contains the definition of space and disposed therein reference systems: connected with the Earth, water-level and the camera system. The second section of the Paper provides a description of the survey system model and the principles of the Charge Coupled Device - CCD array pixel's coordinates (plate coordinates) transformation into the geographic coordinates located on the water-level. In the final section there are presented the general rules of using the worked out method in the optical system. W artykule przedstawiono optyczn? metod? wyznaczania pozycji obiektów nawodnych z l?du. Oparto j? na dwóch punktach odniesienia o znanych wspó?rz?dnych geograficznych. Pierwszy umiejscowiono wysoko na brzegu morza i przeznaczono do zamontowania kamery. Drugi przeznaczono do okre?lania p?aszczyzny horyzontu topocentrycznego i umiejscowiono na poziomie lustra wody. W pierwszej cz??ci artyku?u zdefi niowano przestrze? i rozmieszczone w niej uk?ady odniesienia: zwi?zany z Ziemi?, poziomem lustra wody i kamer?. Drug? cz??? artyku?u stanowi opis modelu uk?adu pomiarowego oraz zasad transformacji wspó?rz?dnych piksela (t?owych) z matrycy CCD na wspó?rz?dne geograficzne punktu umiejscowionego na poziomie lustra wody. W cz??ci ko?cowej zaprezentowano ogólne zasady wykorzystywania opracowanej metody w systemie optycznym.

  8. Quantum back-action in measurements of zero-point mechanical oscillations

    E-print Network

    Farid Ya. Khalili; Haixing Miao; Huan Yang; Amir H. Safavi-Naeini; Oskar Painter; Yanbei Chen

    2012-06-04

    Measurement-induced back action, a direct consequence of the Heisenberg Uncertainty Principle, is the defining feature of quantum measurements. We use quantum measurement theory to analyze the recent experiment of Safavi-Naeini et al. [Phys. Rev. Lett. {\\bf 108}, 033602 (2012)], and show that results of this experiment not only characterize the zero-point fluctuation of a near-ground-state nanomechanical oscillator, but also demonstrate the existence of quantum back-action noise --- through correlations that exist between sensing noise and back-action noise. These correlations arise from the quantum coherence between the mechanical oscillator and the measuring device, which build up during the measurement process, and are key to improving sensitivities beyond the Standard Quantum Limit.

  9. Renormalization-group fixed points, universal phase diagram, and 1/N expansion for quantum liquids with interactions near the unitarity limit

    SciTech Connect

    Nikolic, Predrag; Sachdev, Subir [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2007-03-15

    It has long been known that particles with short-range repulsive interactions in spatial dimension d=1 form universal quantum liquids in the low density limit: all properties can be related to those of the spinless free Fermi gas. Previous renormalization-group (RG) analyses demonstrated that this universality is described by a RG fixed point, infrared stable for d<2, of the zero density gas. We show that for d>2 the same fixed point describes the universal properties of particles with short-range attractive interactions near a Feshbach resonance; the fixed point is now infrared unstable, and the relevant perturbation is the detuning of the resonance. Some exponents are determined exactly, and the same expansion in powers of (d-2) applies for scaling functions for d<2 and d>2. A separate exact RG analysis of a field theory of the particles coupled to 'molecules' finds an alternative description of the same fixed point, with identical exponents; this approach yields a (4-d) expansion which agrees with the recent results of Nishida and Son [Phys. Rev. Lett. 97, 050403 (2006)]. The existence of the RG fixed point implies a universal phase diagram as a function of density, temperature, population imbalance, and detuning; in particular, this applies to the crossover between the Bose-Einstein condensate (BEC) and Bardeen-Cooper-Schrieffer (BCS) superfluid of s-wave paired fermions. Our results open the way towards computation of these universal properties using the standard field-theoretic techniques of critical phenomena, along with a systematic analysis of corrections to universality. We also propose a 1/N expansion [based upon models with Sp(2N) symmetry] of the fixed point and its vicinity, and use it to obtain results for the phase diagram.

  10. Asymptotically free four-Fermi theory in 4 dimensions at the z=3 Lifshitz-like fixed point

    SciTech Connect

    Dhar, Avinash; Mandal, Gautam [Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai 400 005 (India); Wadia, Spenta R. [Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai 400 005 (India); International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Mumbai 400 005 (India)

    2009-11-15

    We show that a Nambu-Jona-Lasinio type four-fermion coupling at the z=3 Lifshitz-like fixed point in 3+1 dimensions is asymptotically free and generates a mass scale dynamically. This result is nonperturbative in the limit of a large number of fermion species. The theory is ultraviolet complete and at low energies exhibits Lorentz invariance as an emergent spacetime symmetry. Many of our results generalize to z=d in odd d spatial dimensions; z=d=1 corresponds to the Gross-Neveu model. The above mechanism of mass generation has potential applications to the fermion mass problem and to dynamical electroweak symmetry breaking. We present a scenario in which a composite Higgs field arises from a condensate of these fermions, which then couples to quarks and leptons of the standard model. Such a scenario could eliminate the need for the Higgs potential and the associated hierarchy problem. We also show that the axial anomaly formula at z=3 coincides with the usual one in the relativistic domain.

  11. Application of Avery-Peterson fixed point theorem to nonlinear boundary value problem of fractional differential equation with the Caputo's derivative

    NASA Astrophysics Data System (ADS)

    Liu, Yang

    2012-12-01

    In this paper, by means of the Avery-Peterson fixed point theorem, we establish the existence result of at least triple positive solutions of four-point boundary value problem of nonlinear differential equation with Caputo's fractional order derivative. An example illustrating our main result is given. Our results complements previous work in the area of boundary value problems of nonlinear fractional differential equations.

  12. Computer-Aided Design of Machine Learning Algorithm: Training Fixed-Point Classifier for On-Chip Low-Power Implementation

    E-print Network

    Li, Xin

    been applied to a variety of big data for numerous commercial applications, including healthcare1 Computer-Aided Design of Machine Learning Algorithm: Training Fixed-Point Classifier for On application of brain computer interface. 1. INTRODUCTION Machine learning is an important technique that has

  13. Analogies between the Torque-Free Motion of a Rigid Body about a Fixed Point and Light Propagation in Anisotropic Media

    ERIC Educational Resources Information Center

    Bellver-Cebreros, Consuelo; Rodriguez-Danta, Marcelo

    2009-01-01

    An apparently unnoticed analogy between the torque-free motion of a rotating rigid body about a fixed point and the propagation of light in anisotropic media is stated. First, a new plane construction for visualizing this torque-free motion is proposed. This method uses an intrinsic representation alternative to angular momentum and independent of…

  14. Conclusions and future work We have shown that, in general, the fixed points of CD differ from those of ML, and thus CD is

    E-print Network

    Carreira-Perpiñán, Miguel Á.

    local optima of ML and CD. We try to characterise the set of all optima of ML and CD for a RBM(6, 4Conclusions and future work We have shown that, in general, the fixed points of CD differ from those of ML, and thus CD is a biased algorithm. However, our empirical results show the bias

  15. Current Work on Furnaces and Data Analysis to Improve the Uniformity and Noise Levels for Metal Fixed Points

    NASA Astrophysics Data System (ADS)

    Head, D. I.; Gray, J.; de Podesta, M.

    2009-02-01

    Ongoing work to improve the uniformity of vertically mounted furnaces, manufactured by Carbolite (e.g., Type TZF12/75—three-zone furnace capable of 1200 °C, with 75 mm inner bore) along the axis and across the working tube and/or equalizing block is reported. This involves adjusting the size of the end zones, the position of the control thermometers, and the use of cascade-control methods. Means regularly used at NPL to reduce electrical noise in some commercially available ac furnaces through a reduction in the voltage used to “fire” the heaters, and better use of thyristor controllers (by extending their cycle time) are described. The need to shield the controllers from local magnetic fields is described. With these measures, the electrical noise from ac furnaces can approach that of dc furnaces, without the large cost of a dc power supply. The application of new data analysis techniques (Allan deviation) will be shown to improve the representation of uninterrupted fixed-point traces (as used in ingot verification rather than PRT calibration). Reduction of statistical noise on the temperature measurements has been achieved for data on the freezing plateau by determining the statistically optimum averaging time. This shows that the statistical uncertainty in the determination of the temperature of a particular freezing plateau is less than 25 ?K and that noise (drift) from other sources, possibly due to variations in room temperature, starts to become appreciable over periods longer than a few tens of minutes. The measurement of freezing and melting plateaux at this level is aided by the introduction of new ASL-F900 bridge(s), and quieter/larger standard resistor baths.

  16. From Emergency to Fix: Point-of-Use Water Filtration Technology in Colonias Along the United States-Mexico Border 

    E-print Network

    Vandewalle, Emily Lauren

    2014-04-30

    Small-scale decentralized facilities and technologies are rapidly becoming a dominant technological fix to deliver water to underserved populations in developing nations. This project examines the case of a university partnership with government...

  17. Closure Report for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada

    Microsoft Academic Search

    D. S. Tobiason

    2003-01-01

    This Closure Report (CR) documents the activities undertaken to close Corrective Action Unit (CAU) 262: Area 25 Septic Systems and Underground Discharge Point, in accordance with the Federal Facility Agreement and Consent Order (FFACO) of 1996. Site closure was performed in accordance with the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) for CAU 262 (U.S. Department of

  18. Encoding of point of view during action observation in the local field potentials of macaque area F5.

    PubMed

    Caggiano, Vittorio; Giese, Martin; Thier, Peter; Casile, Antonino

    2015-02-01

    The discovery of mirror neurons compellingly shows that the monkey premotor area F5 is active not only during the execution but also during the observation of goal-directed motor acts. Previous studies have addressed the functioning of the mirror-neuron system at the single-unit level. Here, we tackled this research question at the network level by analysing local field potentials in area F5 while the monkey was presented with goal-directed actions executed by a human or monkey actor and observed either from a first-person or third-person perspective. Our analysis showed that rhythmic responses are not only present in area F5 during action observation, but are also modulated by the point of view. Observing an action from a subjective point of view produced significantly higher power in the low-frequency band (2-10 Hz) than observing the same action from a frontal view. Interestingly, an increase in power in the 2-10 Hz band was also produced by the execution of goal-directed motor acts. Independently of the point of view, action observation also produced a significant decrease in power in the 15-40 Hz band and an increase in the 60-100 Hz band. These results suggest that, depending on the point of view, action observation might activate different processes in area F5. Furthermore, they may provide information about the functional architecture of action perception in primates. PMID:25442357

  19. Impact of the Change of the Propagation Coefficient at the Break Point on Fixed Channel Assignment for GSM Networks

    Microsoft Academic Search

    Teun M. J. van Berkel; Matti H. A. J. Herben; Raúl Chávez-Santiago; Vladimir Lyandres

    2006-01-01

    The fixed channel assignment problem in GSM networks has been commonly modelled as a constraint satisfaction problem with binary channel separation constraints (graph-colouring model). However, it has been observed that heuristics using direct estimations of carrier-to-interference ratio (CIR) have several advantages over those using binary constraints, being the economisation of spectrum the most important one. This is due to the

  20. A Nondestructive Evaluation Method: Measuring the Fixed Strength of Spot-Welded Joint Points by Surface Electrical Resistivity.

    PubMed

    Shimamoto, Akira; Yamashita, Keitaro; Inoue, Hirofumi; Yang, Sung-Mo; Iwata, Masahiro; Ike, Natsuko

    2013-04-01

    Destructive tests are generally applied to evaluate the fixed strength of spot-welding nuggets of zinc-plated steel (which is a widely used primary structural material for automobiles). These destructive tests, however, are expensive and time-consuming. This paper proposes a nondestructive method for evaluating the fixed strength of the welded joints using surface electrical resistance. A direct current nugget-tester and probes have been developed by the authors for this purpose. The proposed nondestructive method uses the relative decrease in surface electrical resistance, ?. The proposed method also considers the effect of the corona bond. The nugget diameter is estimated by two factors: R Quota, which is calculated from variation of resistance, and a constant that represents the area of the corona bond. Since the maximum tensile strength is correlated with the nugget diameter, it can be inferred from the estimated nugget diameter. When appropriate measuring conditions for the surface electrical resistance are chosen, the proposed method can effectively evaluate the fixed strength of the spot-welded joints even if the steel sheet is zinc-plated. PMID:24891747

  1. Patterns of hypermetria and terminal cocontraction during point-to-point movements demonstrate independent action of trajectory and postural controllers

    PubMed Central

    Ghez, Claude; Asnani, Supriya

    2011-01-01

    We examined elbow muscle activities and movement kinematics to determine how subjects combine elementary control actions in performing movements with one and two trajectory segments. In reaching, subjects made a rapid elbow flexion to a visual target before stabilizing the limb with either a low or a higher level of elbow flexor/extensor coactivity (CoA), which was cued by target diameter. Cursor diameter provided real-time biofeedback of actual muscle CoA. In reversing, the limb was to reverse direction within the target and return to the origin with minimal CoA. We previously reported that subjects overshoot the goal when attempting a reversal after first having learned to reach accurately to the same target. Here we test the hypothesis that this hypermetria results because reversals co-opt the initial feedforward control action from the preceding trained reach, thereby failing to account for task-dependent changes in limb impedance induced by differences in flexor/extensor coactivity as the target is acquired (higher in reaching than reversing). Instructed increases in elbow CoA began mid-reach, thus increasing elbow impedance and reducing transient oscillations present in low CoA movments. Flexor EMG alone increased at movement onset. Test reversals incorporated the initial agonist activity of previous reaches but not the increased coactivity at the target, thus leading to overshoot. Moreover, we observed elevated coactivity in reversals upon returning to the origin even though coactivity in reaching was centered at the goal target. These findings refute the idea that the brain necessarily invokes distinct unitary control actions for reaches and reversals made to the same target. Instead, reaches and reversals share a common control action that initiates trajectories toward their target and another later control action that terminates movement and stabilizes the limb about its final resting posture, which differs in the two tasks. PMID:21849613

  2. Corrective Action Decision Document/ Closure Report for Corrective Action Unit 556: Dry Wells and Surface Release Points, Nevada Test Site, Nevada with Errata Sheet, Revision 0

    SciTech Connect

    Grant Evenson

    2008-09-01

    This Corrective Action Decision Document (CADD)/Closure Report (CR) has been prepared for Corrective Action Unit 556, Dry Wells and Surface Release Points, located at the Nevada Test Site, Nevada, in accordance with the Federal Facility Agreement and Consent Order (FFACO, 1996; as amended February 2008). Corrective Action Unit (CAU) 556 is comprised of four corrective action sites (CASs): • 06-20-04, National Cementers Dry Well • 06-99-09, Birdwell Test Hole • 25-60-03, E-MAD Stormwater Discharge and Piping • 25-64-01, Vehicle Washdown and Drainage Pit The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure of CAU 556 with no further corrective action. To achieve this, corrective action investigation (CAI) activities began on February 7 and were completed on June 19, 2008, as set forth in the Corrective Action Investigation Plan for Corrective Action Unit 556: Dry Wells and Surface Release Points, Nevada Test Site, Nevada (NNSA/NSO, 2007). The purpose of the CAI was to fulfill the following data needs as defined during the data quality objective (DQO) process: • Determine whether contaminants of concern (COCs) are present. • If COCs are present, determine their nature and extent. • Provide sufficient information and data to complete appropriate corrective actions. The CAU 556 data were evaluated based on the data quality assessment process, which demonstrated the quality and acceptability of the data for use in fulfilling the DQO data needs. Analytes detected during the CAI were evaluated against appropriate final action levels (FALs) to identify the COCs for each CAS. The results of the CAI identified COCs at one of the four CASs in CAU 556 that required the completion of a corrective action. Assessment of the data generated from investigation activities conducted at CAU 556 revealed the following: • Corrective Action Sites 06-20-04, 06-99-09, and 25-64-01 do not contain contamination at concentrations exceeding the FALs. • Polychlorinated biphenyl (PCB) contamination above the FAL was identified in the surface and/or shallow subsurface soils at the outfall and around Catch Basin 2, and in soils contained within the catch basins and the manhole at CAS 25-60-03. A corrective action of close in place with a soil removal action and use restriction (UR) was completed at CAS 25-60-03. The PCB-contaminated soils were removed from the outfall area and around Catch Basin 2, and disposed of at a Nevada Test Site landfill as part of a removal action. The catch basins and the manhole were sealed shut by filling them with grout. The end of the outfall pipe was plugged using grout, covered with soil, and the area was regraded. A UR was applied to the entire stormwater system at CAS 25-60-03, which includes the three catch basins, manhole, and associated piping. No further action is the corrective action for CASs 06-20-04, 06-99-09, and 25-64-01. The liquids in the test holes at CAS 06-99-09 were removed for disposal and the features were filled with grout as a best management practice. The drainage pipe between the vehicle washdown pad and the drainage pit at CAS 25-64-01 was sealed at each end as a best management practice. The corrective actions were evaluated on technical merit focusing on performance, reliability, feasibility, safety, and cost. They were judged to meet all requirements for the technical components evaluated. The corrective actions meet all applicable federal and state regulations for closure of the site and will reduce potential exposure pathways to the contaminated media to an acceptable level at CAU 556. Therefore, the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office provides the following recommendations: • Maintain a UR for the entire stormwater drainage system (i.e., three catch basins, one manhole, and associated piping) at CAS 25-60-03. • No further corrective action for CAU 556. • A Notice of Completion to the U.S. Department of Energy, National Nuclear Security Administration Nevada

  3. Critical review of information relevant to the correction of the effect of chemical impurities in gases used for the realization of ITS-90 fixed points

    NASA Astrophysics Data System (ADS)

    Pavese, Franco

    2009-02-01

    According to the Guide to the Expression of Uncertainty in Measurement (GUM) on which the expression of uncertainty in the field of metrology is based, since 1995, 'it is assumed that the results of a measurement have been corrected for all recognised significant systematic effects'. Since the International Temperature Scale of 1990 specifies that the substances used for the realization of the 'fixed points' be 'ideally pure', to fully implement the intent of the GUM corrections should be applied for any chemical impurities that affect the value of the measurand. In general, thermometrists' opinion is that significant laboratory research and more literature search are still needed for further progress towards reliable corrections. This paper, reviewing the available literature data, shows that the situation is more favourable in the case of the substances used for the realization of the Scale reference points in the range 13.8 K to 273.16 K based on the use of hydrogen, neon, oxygen and argon. The appendix reports a similar review also for nitrogen. Then the paper discusses the other conditions, physical-chemical and thermal, of the substances inside the thermometric cells, concurring with the chemical impurity effects to the overall state of knowledge of the realized triple point temperature relevant to the solution of the problem of performing the corrections.

  4. Emergent infinite-randomness fixed points from the extensive random bipartitions of the spin-1 Affleck-Kennedy-Lieb-Tasaki topological state

    E-print Network

    Min Lu; Rajesh Narayanan; Xin Wan; Guang-Ming Zhang

    2015-02-07

    Quantum entanglement under an extensive bipartition can reveal the critical boundary theory of a topological phase in the parameter space. In this study we demonstrate that the infinite-randomness fixed point for spin-1/2 degrees of freedom can emerge from an extensive random bipartition of the spin-1 Affleck-Kennedy-Lieb-Tasaki chain. The nested entanglement entropy of the ground state of the reduced density matrix exhibits a logarithmic scaling with an effective central charge $\\tilde{c} = 0.72 \\pm 0.02 \\approx \\ln 2$. We further discuss, in the language of bulk quantum entanglement, how to understand all phase boundaries and the surrounding Griffiths phases for the antiferromagnetic Heisenberg spin-1 chain with quenched disorder and dimerization.

  5. Infants' Understanding of Looking, Pointing, and Reaching as Cues to Goal-Directed Action

    ERIC Educational Resources Information Center

    Sodian, Beate; Thoermer, Claudia

    2004-01-01

    Phillips, Wellman, and Spelke (2002) provided experimental evidence indicating that by the age of 12 months infants use information about an adult's gaze-direction and emotional expression to predict action. We investigate the generality of this ability, using Phillips et al.'s paradigm across different referential gestures. If infants have a rich…

  6. Multizone Furnace for Analysis of Fixed-Point Realizations in the Range from 1,000°C to 1,700°C

    NASA Astrophysics Data System (ADS)

    Hiti, M.; Bojkovski, J.; Batagelj, V.; Drnovšek, J.

    2008-02-01

    In this article, the development of a laboratory furnace specially designed for analysis of fixed-point plateau realizations in the range from 1,000 °C to 1,700 °C that enables control of various temperature distribution settings along the heating zone length is presented. A total of 13 thermocouples are built into the furnace tube wall to control the temperature as well as to measure the temperature distribution. The furnace is divided into seven independently controlled heating zones. Each heating zone comprises a MoSi2 heating element and its dedicated DC power supply module. The furnace temperature is controlled by manipulating the output voltage of each power supply to control the temperature of each heating element, as estimated from its electrical resistance. The heating power and temperature measurement are fully controlled by a computer using an application written in Lab VIEW, allowing very flexible furnace control. The furnace can be used in air as well as in an inert atmosphere. Measurements of the temperature distribution of the furnace during a melting-point realization are presented.

  7. Towards a Robust Spatio-Temporal Interest Point Detection for Human Action Recognition

    Microsoft Academic Search

    Hossein Shabani; David A. Clausi; John S. Zelek

    2009-01-01

    Spatio-temporal salient features are widely being used for compact representation of objects and motions in video, especially for event and action recognition. The existing feature extraction methods have two main problems: First, they work in batch mode and mostly use Gaussian (linear) scale-space filtering for multi-scale feature extraction. This linear filtering causes the blurring of the edges and salient motions

  8. The power of phase II end-points for different possible mechanisms of action of an experimental treatment

    PubMed Central

    Wason, J.M.S.; Dentamaro, A.; Eisen, T.G.

    2015-01-01

    Background The high failure rate in phase III oncology trials is partly because the signal obtained from phase II trials is often weak. Several papers have considered the appropriateness of various phase II end-points for individual trials, but there has not been a systematic comparison using simulated data to determine which end-point should be used in which situation. Methods In this paper we carry out simulation studies to compare the power of several Response Evaluation Criteria in Solid Tumours (RECIST) response-based end-points for one-arm and two-arm trials, together with progression-free survival (PFS) and testing the tumour-shrinkage directly for two-arm trials. We consider six scenarios: (1) short-term cytotoxic therapy; (2) continuous cytotoxic therapy; (3 + 4) cytostatic therapy; (5 + 6) delayed tumour-shrinkage effect (seen in some immunotherapies). We also consider measurement error in the assessment of tumour size. Results Measurement error affects the type-I error rate and power of single-arm trials, and the power of two-arm trials. Generally no single end-point performed well in all scenarios. Best observed response rate, PFS and directly testing the tumour-shrinkages performed best for a number of scenarios. PFS performed very poorly when the effect of the treatment was short-lived. In scenario 6, where the delay in effect was long, no end-point performed well. Conclusions A clinician setting up a phase II trial should consider the likely mechanism of action the drug will have and choose an end-point that provides high power for that scenario. Testing the difference in tumour-shrinkage is often powerful. Alternative end-points are required for therapies with a long delayed effect. PMID:25840669

  9. Closure Report for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada

    SciTech Connect

    D. S. Tobiason

    2003-07-01

    This Closure Report (CR) documents the activities undertaken to close Corrective Action Unit (CAU) 262: Area 25 Septic Systems and Underground Discharge Point, in accordance with the Federal Facility Agreement and Consent Order (FFACO) of 1996. Site closure was performed in accordance with the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) for CAU 262 (U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office [NNSA/NV, 2002a]). CAU 262 is located at the Nevada Test Site (NTS) approximately 105 kilometers (65 miles) northwest of Las Vegas, Nevada. CAU 262 consists of the following nine Corrective Action Sites (CASs) located in Area 25 of the NTS: CAS 25-02-06, Underground Storage tank CAS 25-04-06, Septic Systems A and B CAS 25-04-07, Septic System CAS 25-05-03, Leachfield CAS 25-05-05, Leachfield CAS 25-05-06, Leachfield CAS 25-05-08, Radioactive Leachfield CAS 25-05-12, Leachfield CAS 25-51-01, Dry Well.

  10. Corrective Action Investigation Plan for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada, Revision No. 1 (9\\/2001)

    Microsoft Academic Search

    2000-01-01

    This corrective action investigation plan contains the U.S. Department of Energy, Nevada Operations Office's approach to collect data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 262 under the Federal Facility Agreement and Consent Order. Corrective Action Unit 262 consists of nine Corrective Action Sites (CASs): Underground Storage Tank (25-02-06), Septic Systems A

  11. [Action of red polarized light on the acupuncture point E-36 increases analgesic effect of corvitin].

    PubMed

    Tamarova, Z A; Lymans'ky?, Iu P; Kostiuk, O I; Mitruzaeva, V A; Lymans'ka, L I

    2010-01-01

    In experiments on mice of lines C57BL/6J and CBA/CaLac, the possibility of strengthening of analgesic effect of corvitin by the action of red polarized light (PL) on the acupoint (AP) E-36 was studied. The pain behavioral response (licking of the painful area) was caused by injection of 5% formalin in hind limb (0.25 microl subcutaneously). The duration of pain response was studied before and after systemic introduction of corvitin (10 mg/kg, intraperitoneal) or joint use of corvitin and red PL (10 minute session). It is established, that after application of red PL on the antinociceptive AP E-36 in all animals an authentic strengthening of antinociceptive effect of corvitin takes place. In C57BL/6J mice, application of corvitin alone weakened the pain response by 29.7% and during combined use of red PL and corvitin, it grew up to 53.1%. Mice of line CBA/CaLac were less sensitive both to corvitin, and PL. In this line, corvitin used alone reduced the duration of pain response by 14%, and by 32.4% during combined use with red PL. Non-traumatic, without side effects, the method of influence by low-intensive PL can be recommended to patients accepting corvitin for strengthening its efficiency. PMID:21469317

  12. The Anti-Inflammatory Actions of Auricular Point Acupressure for Chronic Low Back Pain

    PubMed Central

    Lin, Wei-Chun; Yeh, Chao Hsing; Chien, Lung-Chang; Morone, Natalia E.; Glick, Ronald M.; Albers, Kathryn M.

    2015-01-01

    Background. Auricular point acupressure (APA) is a promising treatment for pain management. Few studies have investigated the physiological mechanisms of APA analgesics. Method. In this pilot randomized clinical trial (RCT), a 4-week APA treatment was used to manage chronic low back pain (CLBP). Sixty-one participants were randomized into a real APA group (n = 32) or a sham APA group (n = 29). Blood samples, pain intensity, and physical function were collected at baseline and after 4 weeks of treatment. Results. Subjects in the real APA group reported a 56% reduction of pain intensity and a 26% improvement in physical function. Serum blood samples showed (1) a decrease in IL-1?, IL-2, IL-6, and calcitonin gene-related peptide [CGRP] and (2) an increase in IL-4. In contrast, subjects in the sham APA group (1) reported a 9% reduction in pain and a 2% improvement in physical function and (2) exhibited minimal changes of inflammatory cytokines and neuropeptides. Statistically significant differences in IL-4 and CGRP expression between the real and sham APA groups were verified. Conclusion. These findings suggest that APA treatment affects pain intensity through modulation of the immune system, as reflected by APA-induced changes in serum inflammatory cytokine and neuropeptide levels. PMID:26170869

  13. Corrective Action Investigation Plan for Corrective Action Unit 406: Area 3 Building 03-74 and Building 03-58 Under ground Discharge Points and Corrective Action Unit 429: Area 3 Building 03-55 and Area 9 Building 09-52 Underground Discharge Points, Tonopah Test Range, Nevada

    SciTech Connect

    DOE/NV

    1999-05-20

    This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references all of the specific information for investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs). According to the FFACO (1996), CASs are sites potentially requiring corrective action(s) and may include solid waste management units or individual disposal or release sites. Corrective Action Units consist of one or more CASs grouped together based on geography, technical similarity, or agency responsibility for the purpose of determining corrective actions. This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at the Underground Discharge Points (UDPs) included in both CAU 406 and CAU 429. The CAUs are located in Area 3 and Area 9 of the Tonopah Test Range (TTR). The TTR, included in the Nellis Air Force Range, is approximately 255 kilometers (km) (140 miles [mi]) northwest of Las Vegas, Nevada.

  14. Computational fluid dynamics simulations of fluid flow and heat transfer at the wall–particle contact points in a fixed-bed reactor

    Microsoft Academic Search

    S. A. Logtenberg; M. Nijemeisland; A. G. Dixon

    1999-01-01

    An accurate description of the fluid flow and heat transfer within a fixed-bed reactor is desirable. The prevailing models of fluid flow invoke either a constant velocity (plug-flow) profile, or make use of a single axial velocity component with radial variation across the tube diameter. However, difficulties in predicting reactor performance and the wide disagreement between effective heat transfer coefficients

  15. The Effects of Point-of-View Video Modeling on Symbolic Play Actions and Play-Associated Language Utterances in Preschoolers with Autism

    ERIC Educational Resources Information Center

    Bonnet, Lauren Kravetz

    2012-01-01

    This single-subject research study was designed to examine the effects of point-of-view video modeling (POVM) on the symbolic play actions and play-associated language of four preschool students with autism. A multiple baseline design across participants was conducted in order to evaluate the effectiveness of using POVM as an intervention for…

  16. Review of AdS/CFT Integrability, Chapter II.3: Sigma Model, Gauge Fixing

    E-print Network

    Marc Magro

    2011-03-01

    This review is devoted to the classical integrability of the AdS5xS5 superstring theory. It starts with a reminder of the corresponding action as a coset model. The symmetries of this action are then reviewed. The classical integrability is then considered from the lagrangian and hamiltonian points of view. The second part of this review deals with the gauge fixing of this theory. Finally, some aspects of the pure spinor formulation are also briefly reviewed.

  17. TP7 : le theor`eme du point fixe en action sous Cette seance de TP7 poursuit la familiarisation avec MATLAB. Elle illustre le

    E-print Network

    Yger, Alain

    ,Niter] = rayonspectral1(A,X,epsilon,k); qui, ´etant donn´e un nombre maximal k d'it´erations autoris´ees, une ma- trice matrice A de la question 1 en prenant k = 100, epsilon=eps, et pour X respectivement 1. Cela ne donne pas associ´e `a la valeur propre dominante ) : [VP,Niter] = AppVPdom(A,X,epsilon,k); qui fournisse, avec les

  18. Action imitation at 1½ years is better than pointing gesture in predicting late development of language production at 3 years of age.

    PubMed

    Zambrana, Imac M; Ystrom, Eivind; Schjølberg, Synnve; Pons, Francisco

    2013-01-01

    This study examined whether poor pointing gestures and imitative actions at 18 months of age uniquely predicted late language production at 36 months, beyond the role of poor language at 18 months of age. Data from the Norwegian Mother and Child Cohort Study were utilized. Maternal reports of the children's nonverbal skills and language were gathered for 42,517 children aged 18 months and for 28,107 of the same children at 36 months. Panel analysis of latent variables revealed that imitative actions, language comprehension, and language production uniquely contributed to predicting late development of language production, while pointing gestures did not. It is suggested that the results can be explained by underlying symbolic representational skills at 18 months. PMID:23033814

  19. Matter induced bimetric actions for gravity

    SciTech Connect

    Manrique, Elisa, E-mail: manrique@thep.physik.uni-mainz.de [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany); Reuter, Martin, E-mail: reuter@thep.physik.uni-mainz.de [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany); Saueressig, Frank, E-mail: saueressig@thep.physik.uni-mainz.de [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany)

    2011-02-15

    Research Highlights: > Gravitational effective action in the bimetric truncation. > RG flow in the large N limit of matter coupled to gravity. > Asymptotically safe theory found in the large N expansion. - Abstract: The gravitational effective average action is studied in a bimetric truncation with a nontrivial background field dependence, and its renormalization group flow due to a scalar multiplet coupled to gravity is derived. Neglecting the metric contributions to the corresponding beta functions, the analysis of its fixed points reveals that, even on the new enlarged theory space which includes bimetric action functionals, the theory is asymptotically safe in the large N expansion.

  20. Research and operational products from the combination of a monthly hydrographic station and an oceanic buoy: The Biscay AGL fixed-point water column observatory.

    NASA Astrophysics Data System (ADS)

    Lavin, Alicia; Cano, Daniel; González-Pola, Cesar; Tel, Elena; Rodriguez, Carmen; Ruiz, Manuel; Somavilla, Raquel

    2015-04-01

    Long term time series are an important tool for increasing the knowledge of ocean processes as well as for studying water masses variability in different time scales and changes and tendencies in marine ecosystems. Time series has been classically obtained by oceanographic ships that regularly cover standard sections and stations. From 1991, shelf and slope waters of the Southern Bay of Biscay are regularly sampled in a monthly hydrographic line north of Santander to a depth of 1000 m in early stages and for the whole water column down to 2580 m in recent times. Nearby, in June 2007, the IEO deployed an oceanic-meteorological buoy (AGL Buoy, 43° 50.67'N; 3° 46.20'W, and 40 km offshore, www.boya-agl.st.ieo.es). The long-term hydrographical record have allowed to define the seasonality, trends, and interannual variability at all levels, including the mixing layer and the main water masses North Atlantic Central Water and Mediterranean Water. The relation of these changes with high frequency surface conditions has been examined using the AGL buoy data from 2007 as well as satellite and reanalysis data. On that context and using that combination of sources, some products and quality controlled series of high interest and utility for scientific purposes have been developed and are offered hourly in the web page. Main products obtained are: SST and SSS anomalies, wave significant height character with respect to monthly average, and currents with respect to seasonal averages. Ocean-atmosphere heat fluxes (latent and sensible) are computed from the buoy atmospheric and oceanic measurements. Estimations of the mixed layer depth and bulk series at different water levels are provided in a monthly basis. Quality controlled series are provided for sea surface salinity, oxygen and chlorophyll data. Some sensors are particularly affected by biofouling, and monthly visits to the buoy permit to follow these sensors behaviour. Chlorophyll-fluorescence sensor is the main concern, but Dissolved Oxygen sensor is also problematic. Periods of realistic smooth variations present strong offset that is corrected based on the Winkler analysis of water samples. The incorporation of these observatories on larger scale research programs, as done in 2003 in the framework of the VACLAN and COVACLAN projects, is important in order to provide them with a larger spatial dimension and maximize its utility for process-oriented studies. In 2003, the Santander section was extended 90 miles offshore in the framework of a large-scale hydrographic and circulation monitoring program. Partnerships in a large EU project as FixO3 has provided tools for coordination, homogenization and data validation as well as improve the use of chemical-biological data.

  1. Methods for the assessment of correction for chemical-impurity effects and related uncertainty in ITS-90 fixed points, namely of e-H2, Ne, O2 and Ar

    NASA Astrophysics Data System (ADS)

    Pavese, Franco

    2011-10-01

    The expression of uncertainty in the field of metrology is based, since 1993, on the Guide to the Expression of Uncertainty in Measurement. According to this, 'it is assumed that the results of a measurement have been corrected for all recognized significant systematic effects'. Since the International Temperature Scale of 1990 considers the substances used for the realization of the 'fixed points' to be ideally pure, to fully implement the intent of the GUM corrections should be applied for any chemical impurities that affect the value of the measurand. The present paper aims at reviewing an aspect that must be tackled to arrive to reliable and scientifically sound corrections: the use of an appropriate statistical method. In addition to the SIE, OME and hybrid methods recommended by the CCT, two new approaches are proposed in this paper, called one-sided OME and Average Overall Estimate (AOE). They are illustrated and their merits compared with the previous one, by applying them for the correction of the measured values of the triple-point temperature of the four gaseous substances (hydrogen, neon, oxygen and argon) used for the realization of the ITS-90 reference points in the range 13.8 K to 273.16 K. Some suggestions are drawn from the resulting evidence.

  2. Action Recognition Based on A Bag of 3D Points Advanced Multimedia Research Lab, ICT Research Institute

    E-print Network

    Narasayya, Vivek

    of points posture model to deal with occlusions through simulation. 1. Introduction Recognition of human on the sequences of depth maps. As it is well known, the human body is an articulated system of rigid segments configuration of the segments or body posture [18]. Given a sequence of depth maps, if the body joints can be 1

  3. CONSTRUCTION OF MULTIPLY FIXED n-VALUED MAPS

    E-print Network

    Brown, Robert F.

    of n-valued maps and of their fixed point theory was initiated by Schirmer in [33], [34], [35]. In [34 = n,1. However, since X = X in general, we cannot study the fixed point theory of p-1 . A larger class fixed points. Let p: X X be a finite covering space, of degree n, of a connected finite polyhedron

  4. Biogenesis and Mechanism of Action of Small Non-Coding RNAs: Insights from the Point of View of Structural Biology

    PubMed Central

    Costa, Marina C.; Leitão, Ana Lúcia; Enguita, Francisco J.

    2012-01-01

    Non-coding RNAs are dominant in the genomic output of the higher organisms being not simply occasional transcripts with idiosyncratic functions, but constituting an extensive regulatory network. Among all the species of non-coding RNAs, small non-coding RNAs (miRNAs, siRNAs and piRNAs) have been shown to be in the core of the regulatory machinery of all the genomic output in eukaryotic cells. Small non-coding RNAs are produced by several pathways containing specialized enzymes that process RNA transcripts. The mechanism of action of these molecules is also ensured by a group of effector proteins that are commonly engaged within high molecular weight protein-RNA complexes. In the last decade, the contribution of structural biology has been essential to the dissection of the molecular mechanisms involved in the biosynthesis and function of small non-coding RNAs. PMID:22949860

  5. An effective action for asymptotically safe gravity

    NASA Astrophysics Data System (ADS)

    Bonanno, Alfio

    2012-04-01

    Asymptotically safe theories of gravitation have received great attention in recent times. In this framework an effective action embodying the basic features of the renormalized flow around the non-Gaussian fixed-point is derived and its implications for the early universe are discussed. In particular, a landscape of a countably infinite number of cosmological inflationary solutions characterized by an unstable de Sitter phase lasting for a large enough number of e-folds is found.

  6. Neuronal Network Triggering a Fixed Action Pattern

    Microsoft Academic Search

    A. O. D. Willows; G. Hoyle

    1969-01-01

    Bursts of impulses in groups of brain cells of the nudibranch Tritonia trigger prolonged swimming that is identical to the natural escape response. The cells in which the activity occurs form two bilaterally symmetrical groups of at least 30 cells in each pleural ganglion. These neurons are interconnected by pathways that have a low electrical resistance, both within a ganglion

  7. Holographic non-Fermi-liquid fixed points

    E-print Network

    Faulkner, Tom

    Techniques arising from string theory can be used to study assemblies of strongly interacting fermions. Via this ‘holographic duality’, various strongly coupled many-body systems are solved using an auxiliary theory of ...

  8. Holographic fermionic fixed points in d=3

    Microsoft Academic Search

    Joshua L. Davis; Hamid Omid; Gordon W. Semenoff

    2011-01-01

    We present a top-down string theory holographic model of strongly interacting relativistic 2 + 1-dimensional fermions, paying careful attention to the discrete symmetries of parity and time reversal invariance. Our construction is based on probe D7-branes in AdS 5 × S 5, stabilized by internal fluxes. We find three solutions, a parity and time reversal invariant conformal field theory which

  9. From Fixed Points to the Fifth Dimension

    E-print Network

    Raman Sundrum

    2012-09-17

    4D Lorentzian conformal field theory (CFT) is mapped into 5D anti-de Sitter spacetime (AdS), from the viewpoint of "geometrizing" conformal current algebra. A large-N expansion of the CFT is shown to lead to (infinitely many) weakly coupled AdS particles, in one-to-one correspondence with minimal-color-singlet CFT primary operators. If all but a finite number of "protected" primary operators have very large scaling dimensions, it is shown that there exists a low-AdS-curvature effective field theory regime for the corresponding finite set of AdS particles. Effective 5D gauge theory and General Relativity on AdS are derived in this way from the most robust examples of protected CFT primaries, Noether currents of global symmetries and the energy-momentum tensor. Witten's prescription for computing CFT local operator correlators within the AdS dual is derived. The main new contribution is the derivation of 5D locality of AdS couplings. This is accomplished by studying a confining IR-deformation of the CFT in the large-N "planar" approximation, where the discrete spectrum and existence of an S-matrix allow the constraints of unitarity and crossing symmetry to be solved (in standard fashion) by a tree-level expansion in terms of 4D local "glueball" couplings. When the deformation is carefully removed, this 4D locality (with plausible technical assumptions specifying its precise nature) combines with the restored conformal symmetry to yield 5D AdS locality. The sense in which AdS/CFT duality illustrates the possibility of emergent relativity, and the special role of strong coupling, are briefly discussed. Care is taken to conclude each step with well-defined mathematical expressions and convergent integrals.

  10. FIXED POINT THEORY AND STRUCTURAL OPTIMIZATION

    Microsoft Academic Search

    ROBERT LEVY

    1991-01-01

    This paper discusses the existence of solutions to problems of structural optimization which are of an iterative nature and possess explicit recurrence relationships for redesign. Five optimization problems are presented. These are the stress constrained truss, the stress constrained prestressed truss under two loading conditions, the natural frequency constrained truss, the overall stability constrained truss and the rigid frame. Common

  11. Fixed point varieties on affine flag manifolds

    Microsoft Academic Search

    D. Kazhdan; G. Lusztig

    1988-01-01

    We study the space of Iwahori subalgebras containing a given element of a semisimple Lie algebra over C((?)). We also define\\u000a and study a map from nilpotent orbits in a semisimple Lie algebra over C to conjugacy classes in the Weyl group.

  12. The American Suzuki Institute at the University of Wisconsin-Stevens Point: the Suzuki Method in Action

    NSDL National Science Digital Library

    Dr. Shinichi Suzuki developed the Suzuki method of violin instruction in Japan shortly after World War II. The University of Wisconsin-Stevens Point (UWSP) is home to the American Suzuki Institute, founded in 1971 by UWSP professor of violin, Margery V. Aber, who was an admirer of Suzuki's teaching method. This digital collection presents moving image footage recorded in 1976, when Suzuki spent two weeks at the American Suzuki Institute, giving lectures and demonstrations, as well as teaching both master classes and group classes. A search on the site for Suzuki will retrieve 35 videos in an easily browsed list. Additional instructions for searching by topic are given in the introductory essay, and it is also possible to search by the titles of musical compositions. For example, a keyword search on twinkle yields 5 recordings of Suzuki's students playing "Twinkle, twinkle little star" or other Twinkle variations.

  13. Algorithmic-Reducibility = Renormalization-Group Fixed-Points; ``Noise''-Induced Phase-Transitions (NITs) to Accelerate Algorithmics (``NIT-Picking'') Replacing CRUTCHES!!!: Gauss Modular/Clock-Arithmetic Congruences = Signal X Noise PRODUCTS..

    NASA Astrophysics Data System (ADS)

    Siegel, J.; Siegel, Edward Carl-Ludwig

    2011-03-01

    Cook-Levin computational-"complexity"(C-C) algorithmic-equivalence reduction-theorem reducibility equivalence to renormalization-(semi)-group phase-transitions critical-phenomena statistical-physics universality-classes fixed-points, is exploited with Gauss modular/clock-arithmetic/model congruences = signal X noise PRODUCT reinterpretation. Siegel-Baez FUZZYICS=CATEGORYICS(SON of ``TRIZ''): Category-Semantics(C-S) tabular list-format truth-table matrix analytics predicts and implements "noise"-induced phase-transitions (NITs) to accelerate versus to decelerate Harel [Algorithmics(1987)]-Sipser[Intro. Theory Computation(1997) algorithmic C-C: "NIT-picking" to optimize optimization-problems optimally(OOPO). Versus iso-"noise" power-spectrum quantitative-only amplitude/magnitude-only variation stochastic-resonance, this "NIT-picking" is "noise" power-spectrum QUALitative-type variation via quantitative critical-exponents variation. Computer-"science" algorithmic C-C models: Turing-machine, finite-state-models/automata, are identified as early-days once-workable but NOW ONLY LIMITING CRUTCHES IMPEDING latter-days new-insights!!!

  14. Memories of bug fixes

    Microsoft Academic Search

    Sunghun Kim; Kai Pan; E. E. James Whitehead Jr.

    2006-01-01

    The change history of a software project contains a rich collection of code changes that record previous development experience. Changes that fix bugs are especially interesting, since they record both the old buggy code and the new fixed code. This paper presents a bug finding algorithm using bug fix memories: a project-specific bug and fix knowledge base developed by analyzing

  15. Full and partial gauge fixing

    SciTech Connect

    Shirzad, A. [Institute for Studies in Theoretical Physics and Mathematics, P. O. Box 5531, Tehran 19395 (Iran, Islamic Republic of) and Department of Physics, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2007-08-15

    Gauge fixing may be done in different ways. We show that using the chain structure to describe a constrained system enables us to use either a full gauge, in which all gauged degrees of freedom are determined, or a partial gauge, in which some first class constraints remain as subsidiary conditions to be imposed on the solutions of the equations of motion. We also show that the number of constants of motion depends on the level in a constraint chain in which the gauge fixing condition is imposed. The relativistic point particle, electromagnetism, and the Polyakov string are discussed as examples and full or partial gauges are distinguished.

  16. Multiple point action mechanism of valproic acid-teratogenicity alleviated by folic acid, vitamin C, and N-acetylcysteine in chicken embryo model.

    PubMed

    Hsieh, Chiu-Lan; Wang, Hui-Er; Tsai, Wan-Jane; Peng, Chiung-Chi; Peng, Robert Y

    2012-01-27

    The teratogenicity of antiepilepsy drug valproic acid (VPA) mostly is found in genetic and somatic levels, causing teratogenesis involving neurotubular defects (NTDs), anencephaly, lumbosacral meningomyelocele, and leg dysfunction due to spina bifida aperta. A diversity of nutraceutics have been tried to alleviate the risk of VPA-teratogenicity. The effect was varying. In order to promote the preventive prescription, to find out its action mechanism can be rather crucial. We used chicken embryo model to try the effect of folic acid (FA), ascorbic acid (AA), and N-acetyl cysteine (NAC). VPA at 30mM showed the higher malformation rate (66.7%) with the least mortality (22.2%). Pathological findings indicated that the cervical muscle was more susceptible to VPA injury than the ankle muscle. VPA downregulated levels of superoxide dismutase (SOD), glutathione (GSH), histone deacetylase (HDAC) and folate, and upregulated H(2)O(2) and homocysteine. FA, AA, and NAC significantly upregulated SOD, but only AA alone activated GSH. AA and NAC downregulated H(2)O(2), while FA was totally ineffective. All three nutraceutics comparably rescued HDAC with simultaneously suppressed homocysteine accumulation and folate re-elevation, although less effectively by NAC. Based on these data, we conclude VPA possesses "Multiple Point Action Mechanism". In addition to affecting the cited transcription and translation levels, we hypothesize that VPA competitively antagonize the glutamic acid to couple with pteroic acid in biosynthesis of dihydrofolic acid (DHFA). H(2)O(2) directly destroyed the NADPH reducing system at dihydrofolate reductase (DHFR) and methylene tetrahydrofolate reductase (MTHFR) levels, while completely restored by AA, an implication in preservation of intact apoenzymes. In addition, the GSH-GSSG system is sandwiched between the reducing systems NADPH/NADP and DHA-AA, its net balance is highly dependent on in situ in vivo Redox state, hence folic acid transformation is varying. To rescue the VPA-induced teratogenicity, simultaneous multiple prescriptions are suggested. PMID:22051200

  17. Electrical Discharges from Pointed Conductors

    Microsoft Academic Search

    John Zeleny

    1920-01-01

    Surface Action in Electrical Discharges from Points.-The lag phenomena shown by the discharges from some points indicate a special surface action. Various possible surface actions are discussed and attention is centered upon an adhering layer of gas molecules. Further evidence is sought in discharges from points made of different materials. Electrical Discharges from Water Points. Surface Electric Intensities and Stopping

  18. Serial floating point formatter

    SciTech Connect

    Peterson, R. D.; Penner, W. A.

    1985-11-12

    A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

  19. Fixed points in programming: datatypes and protocols. Fixed points in programming: datatypes and

    E-print Network

    will be common ... Computing has blindly entered a new era of parallel power! There is no turning back ... #12 of syntax but no semantics ... Physics (quantum computing), biological computing, and environmental and protocols. J.R.B. Cockett Department of Computer Science University of Calgary Alberta, Canada robin

  20. 85 years of Nielsen theory: Periodic Points P. Christopher Staecker

    E-print Network

    Staecker, P. Christopher

    CT Nielsen Theory and Related Topics 2013 Staecker (Fairfield U.) Periodic points 1 / 46 #12;Fixed point theory is about f (x) = x. Staecker (Fairfield U.) Periodic points 2 / 46 #12;Fixed point theory.) Periodic points 2 / 46 #12;Fixed point theory is about f (x) = x. We want to generalize the ideas to f n

  1. Corrective Action Investigation Plan for Corrective Action Unit 406: Area 3 Building 03-74 and Building 03-58 Under ground Discharge Points and Corrective Action Unit 429: Area 3 Building 03-55 and Area 9 Building 09-52 Underground Discharge Points, Tonopah Test Range, Nevada

    Microsoft Academic Search

    1999-01-01

    This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE\\/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references

  2. Comparison of toxicogenomics and traditional approaches to inform mode of action and points of departure in human health risk assessment of benzo[a]pyrene in drinking water.

    PubMed

    Moffat, Ivy; Chepelev, Nikolai L; Labib, Sarah; Bourdon-Lacombe, Julie; Kuo, Byron; Buick, Julie K; Lemieux, France; Williams, Andrew; Halappanavar, Sabina; Malik, Amal I; Luijten, Mirjam; Aubrecht, Jiri; Hyduke, Daniel R; Fornace, Albert J; Swartz, Carol D; Recio, Leslie; Yauk, Carole L

    2015-01-01

    Toxicogenomics is proposed to be a useful tool in human health risk assessment. However, a systematic comparison of traditional risk assessment approaches with those applying toxicogenomics has never been done. We conducted a case study to evaluate the utility of toxicogenomics in the risk assessment of benzo[a]pyrene (BaP), a well-studied carcinogen, for drinking water exposures. Our study was intended to compare methodologies, not to evaluate drinking water safety. We compared traditional (RA1), genomics-informed (RA2) and genomics-only (RA3) approaches. RA2 and RA3 applied toxicogenomics data from human cell cultures and mice exposed to BaP to determine if these data could provide insight into BaP's mode of action (MOA) and derive tissue-specific points of departure (POD). Our global gene expression analysis supported that BaP is genotoxic in mice and allowed the development of a detailed MOA. Toxicogenomics analysis in human lymphoblastoid TK6 cells demonstrated a high degree of consistency in perturbed pathways with animal tissues. Quantitatively, the PODs for traditional and transcriptional approaches were similar (liver 1.2 vs. 1.0 mg/kg-bw/day; lungs 0.8 vs. 3.7 mg/kg-bw/day; forestomach 0.5 vs. 7.4 mg/kg-bw/day). RA3, which applied toxicogenomics in the absence of apical toxicology data, demonstrates that this approach provides useful information in data-poor situations. Overall, our study supports the use of toxicogenomics as a relatively fast and cost-effective tool for hazard identification, preliminary evaluation of potential carcinogens, and carcinogenic potency, in addition to identifying current limitations and practical questions for future work. PMID:25605026

  3. Note On The Dilaton Effective Action And Entanglement Entropy

    E-print Network

    Shamik Banerjee

    2014-06-11

    In this note we do the analysis of entanglement entropy more carefully when the non-conformal theory flows to a non-trivial IR fixed point. In particular we emphasize the role of the trace of the energy-momentum tensor in these calculations. We also compare the current technique for evaluating the entanglement entropy, particularly the Green's function method for gaussian theories, with the dilaton effective action approach and show that they compute identical quantities. As a result of this, the dilaton effective action approach can be thought of as an extension of Green's function technique to interacting theories.

  4. Note On The Dilaton Effective Action And Entanglement Entropy

    E-print Network

    Banerjee, Shamik

    2014-01-01

    In this note we do the analysis of entanglement entropy more carefully when the non-conformal theory flows to a non-trivial IR fixed point. In particular we emphasize the role of the trace of the energy-momentum tensor in these calculations. We also compare the current technique for evaluating the entanglement entropy, particularly the Green's function method for gaussian theories, with the dilaton effective action approach and show that they compute identical quantities. As a result of this, the dilaton effective action approach can be thought of as an extension of Green's function technique to interacting theories.

  5. Managing multiple non-point pressures on water quality and ecological habitat: Spatially targeting effective mitigation actions at the landscape scale.

    NASA Astrophysics Data System (ADS)

    Reaney, S. M.

    2014-12-01

    Catchment systems deliver many benefits to society and ecology but also produce a range of undesirable externalities including flooding, diffuse pollution from agriculture, forestry and urban areas and the export of FIOs. These diffuse pressures are coupled with increasing stream temperature pressures on river from projected climate change. These pressures can be reduced through actions at the landscape scale but are often tackled individually. Any intervention may have benefits for other pressures and hence the challenge is to consider all of the different pressures simultaneously to find solutions with high levels of cross-pressure benefits. The general approach taken within this research has been to use simple but spatially distributed models to predict the pattern of each of the pressures at the landscape scale. These models follow a minimum information requirement approach along the lines of the SCIMAP modelling approach (www.scimap.org.uk). This approach aims to capture the key features of the processes in relative rather than an absolute sense and hence is good at determining key locations to act within a landscape for maximum benefit. The core of the approach is to define the critical sources areas for each pressure based on the analysis of the pattern of the pressure in the landscape and the connectivity from the sources areas to the rivers and lakes. To identify the optimal locations with the landscape for mitigation actions, the benefit of a mitigation action at each location in the landscape needs to be considered. However, as one action has been made, it may change the suitability of other locations in the landscape. For example, as tree cover reduces the temperature in one river reach, the impacts of this cooling are transported downstream with the flow. Therefore, actions need to be considered in sets across multiple sites and objectives to identify the optimal actions set. These modelling results are integrated into a decision support tool which allows the user to explore the implications of considering an individual pressure as opposed to the set of pressures. This is achieved by allowing the user to change the importance of different pressures to identify the optimal locations for a custom combination of pressures. For example, reductions in flood risk can be prioritized over reductions in fine sediment.

  6. The Fix Issue 6 

    E-print Network

    Multiple Contributors

    1989-01-01

    story as well. It was great to see it, as I'm currently enjoying Mary Renault's The Persian Boy again. That's about all ror now, except to say that the next issue of THE FIX will appear at ZCon. I know I'm giving you all a very short deadline...

  7. Fixed pitch wind turbines

    Microsoft Academic Search

    D. B. Fenn; L. A. Viterna

    1978-01-01

    Wind turbines designed for fixed pitch operation offer potential reductions in the cost of the machine by eliminating many costly components. It was shown that a rotor can be designed which produces the same energy annually as Mod-0 but which regulates its power automatically by progressively stalling the blades as wind speed increases. Effects of blade twist, taper, root cutout,

  8. [Shaping the future of vocational rehabilitation of adults: eight fields of action as starting points for a cross-actor innovation process].

    PubMed

    Riedel, H-P; Ellger-Rüttgardt, S; Karbe, H; Niehaus, M; Rauch, A; Schian, H-M; Schmidt, C; Schott, T; Schröder, H; Spijkers, W; Wittwer, U

    2009-12-01

    Established by the Federal Ministry of Labour and Social Affairs (BMAS) in October 2007, the Scientific Expert Group RehaFutur had been commissioned to elaborate cornerstones for the medium- and long-term development of vocational rehabilitation of adults with disabilities (re-integration). Initial questions inter alia were as follows: Which function should vocational rehabilitation have in a service- and knowledge-oriented working world that will increasingly be affected by demographic change? How can disabled persons' right to occupational participation by way of vocational rehabilitation, a right stipulated both under the German constitution and in German law, be realized as needed also in the future? Various fields of action have been derived on the basis, for one, of an investigation of the factors, social law, social and education policy as well as European, influencing vocational rehabilitation and, for the other, of an evaluation of current labour market and demographic developments. Dealt with in the fields of action outlined are the aspects: equitable opportunities of access, developmental and needs orientation, closeness to the real occupational and working world, as well as the role of self-determination and self-responsibility. The fields of action are to be understood as framework concept for shaping a cross-actor innovation process. Sustainable vocational rehabilitation is characterized in particular by the fact that it is specifically targeted at promoting disabled persons' self-determination and self-responsibility actively using these in the process and that it strengthens an independent lifestyle, ensures social participation by inclusive structures; also, it facilitates continued participation in working life by ongoing education involving holistic development of professional and personal competencies oriented towards the individual's resources and potentials, safeguarding it by systematic networking with companies. The concept presented for vocational rehabilitation of adults with disabilities encompasses a change of paradigms which service carriers and providers will have to face jointly and including the service users, the rehabilitants. PMID:20069522

  9. Cannabidiol As a Putative Novel Therapy for Diabetic Retinopathy: A Postulated Mechanism of Action as an Entry Point for Biomarker-Guided Clinical Development

    PubMed Central

    Liou, GI; El-Remessy, AB; Ibrahim, AS; Caldwell, RB; Khalifa, YM; Gunes, A; Nussbaum, JJ

    2010-01-01

    Diabetic retinopathy is a leading cause of blindness in the Western world. However, treatment options for diabetic retinopathy are limited and display poor efficacy with marked patient-to-patient variation in therapeutic outcomes. Discovery of new molecular entities acting on mechanistically novel biological pathways remains as one of the key research priorities in diabetic retinopathy. Moreover, given the variable success of the existing treatment modalities, a targeted and personalized drug development strategy could be more fruitful for rational and successful transition of preclinical discoveries to the clinical realm. This review is focused on cannabidiol, a non-psychoactive native cannabinoid, as an emerging and novel therapeutic modality based on systematic studies in animal models of inflammatory retinal diseases including diabetic retinopathy - one of the retinal diseases associated with vascular neuroinflammation. We present the postulated and preclinically documented novel mechanisms that may underlie cannabidiol mode of action in diabetic retinopathy. We discuss the interindividual variation in pharmacokinetic pathways as well as in the SLC29A1 gene, a molecular target for cannabidiol. We emphasize that the novel mode of action of cannabidiol and the previous failures with nontargeted interventions in diabetic retinopathy collectively demand a more rational and personalized clinical development strategy for compounds that have shown promise at the preclinical stage. Moreover, it is noteworthy that ophthalmology, as a medical specialty, has fewer examples (e.g., compared to oncology) of personalized medicine and biomarker applications thus far. Understanding the biological action of cannabidiol in preclinical studies is therefore a rational first step to proactively map the pertinent biomarker strategies in clinical proof of concept studies in diabetic retinopathy, and to allow advances at the hitherto neglected intersection of personalized medicine and ophthalmology. PMID:20953236

  10. Procedures for behavioral experiments in head-fixed mice.

    PubMed

    Guo, Zengcai V; Hires, S Andrew; Li, Nuo; O'Connor, Daniel H; Komiyama, Takaki; Ophir, Eran; Huber, Daniel; Bonardi, Claudia; Morandell, Karin; Gutnisky, Diego; Peron, Simon; Xu, Ning-long; Cox, James; Svoboda, Karel

    2014-01-01

    The mouse is an increasingly prominent model for the analysis of mammalian neuronal circuits. Neural circuits ultimately have to be probed during behaviors that engage the circuits. Linking circuit dynamics to behavior requires precise control of sensory stimuli and measurement of body movements. Head-fixation has been used for behavioral research, particularly in non-human primates, to facilitate precise stimulus control, behavioral monitoring and neural recording. However, choice-based, perceptual decision tasks by head-fixed mice have only recently been introduced. Training mice relies on motivating mice using water restriction. Here we describe procedures for head-fixation, water restriction and behavioral training for head-fixed mice, with a focus on active, whisker-based tactile behaviors. In these experiments mice had restricted access to water (typically 1 ml/day). After ten days of water restriction, body weight stabilized at approximately 80% of initial weight. At that point mice were trained to discriminate sensory stimuli using operant conditioning. Head-fixed mice reported stimuli by licking in go/no-go tasks and also using a forced choice paradigm using a dual lickport. In some cases mice learned to discriminate sensory stimuli in a few trials within the first behavioral session. Delay epochs lasting a second or more were used to separate sensation (e.g. tactile exploration) and action (i.e. licking). Mice performed a variety of perceptual decision tasks with high performance for hundreds of trials per behavioral session. Up to four months of continuous water restriction showed no adverse health effects. Behavioral performance correlated with the degree of water restriction, supporting the importance of controlling access to water. These behavioral paradigms can be combined with cellular resolution imaging, random access photostimulation, and whole cell recordings. PMID:24520413

  11. Fixed Resistor Placement

    NSDL National Science Digital Library

    Flash Player 6 or greater is required to view this website. You are a student worker in the ACME Community College electronics department. Students have left 50 fixed resistors on the lab bench. Your supervisor has asked you to return these resistors to the proper drawers and she has given you 10 minutes to complete the task. Enter your name and click the Start button. A fixed resistor will be displayed. Click on and drag the resistor to the proper drawer. If placed in the correct drawer, a green light will be displayed. If placed incorrectly, a red light will be displayed and the resistor will be displayed at the bottom of the screen.

  12. 68 FR 49416 - Fisheries of the Exclusive Economic Zone Off Alaska; Allocation of Pacific Cod Among Fixed Gear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2003-08-18

    ...Allocation of Pacific Cod Among Fixed Gear Sectors AGENCY: National Marine Fisheries...allowable catch (TAC) among the fixed gear sectors. In addition, this action would...annual BSAI Pacific cod allocation to jig gear is seasonally apportioned, and...

  13. Fixed pitch wind turbines

    NASA Technical Reports Server (NTRS)

    Fenn, D. B.; Viterna, L. A.

    1978-01-01

    Wind turbines designed for fixed pitch operation offer potential reductions in the cost of the machine by eliminating many costly components. It was shown that a rotor can be designed which produces the same energy annually as Mod-0 but which regulates its power automatically by progressively stalling the blades as wind speed increases. Effects of blade twist, taper, root cutout, and airfoil shape on performance are discussed as well as various starting technqiues.

  14. Neutrophilic Fixed Drug Eruption.

    PubMed

    Waldman, Leah; Reddy, Swathi B; Kassim, Andrea; Dettloff, Jennifer; Reddy, Vijaya B

    2015-07-01

    Fixed drug eruption (FDE) is a cutaneous reaction to a medication that recurs in the same fairly localized site with each exposure to the offending drug. The classical histopathologic findings in FDE consist of an interface dermatitis with predominantly lymphocytic inflammatory cell infiltrate. An unusual case of FDE in a 27-year-old pregnant woman who presented with widespread lesions and a predominantly neutrophilic infiltrate on histopathologic examination is reported. PMID:25072682

  15. The Fix Issue 10

    E-print Network

    Multiple Contributors

    1991-01-01

    . ....................... .42 Lammas Eve, by Jennet Morgan ................................................. 44 Hutch Fever, by Theresa Kyle .................................................... .47 Exile to Freedom, Chapter 2, by Martha J. Bonds ............... 62 SVE-p.60... TACS - cover, pp. 9,19, 26, 63, 69 THE FIX is $5 per issue or $19.95 for a 3 issue subscription. Order from Carol Davis, 5 Paca Place, Rockville, MD 20852. Send contributions to Martha Bonds, 5905 Yorkwood Rd. , Baltimore, MD 21239 if) April, 1991...

  16. Action and entanglement in gravity and field theory.

    PubMed

    Neiman, Yasha

    2013-12-27

    In nongravitational quantum field theory, the entanglement entropy across a surface depends on the short-distance regularization. Quantum gravity should not require such regularization, and it has been conjectured that the entanglement entropy there is always given by the black hole entropy formula evaluated on the entangling surface. We show that these statements have precise classical counterparts at the level of the action. Specifically, we point out that the action can have a nonadditive imaginary part. In gravity, the latter is fixed by the black hole entropy formula, while in nongravitating theories it is arbitrary. From these classical facts, the entanglement entropy conjecture follows by heuristically applying the relation between actions and wave functions. PMID:24483789

  17. Effective Potential of the Conformal Factor: Gravitational Average Action and Dynamical Triangulations

    E-print Network

    Jan-Eric Daum; Martin Reuter

    2008-06-24

    We discuss the effective potential of the conformal factor in the effective average action approach to Quantum Einstein Gravity. Without invoking any truncation or other approximations we show that if the theory has has a non-Gaussian ultraviolet fixed point and is asymptotically safe the potential has a characteristic behavior near the origin. We argue that this characteristic behavior has already been observed in numerical simulations within the Causal Dynamical Triangulation approach.

  18. Fixed target facility at the SSC

    SciTech Connect

    Loken, S.C.; Morfin, J.G.

    1985-01-01

    The question of whether a facility for fixed target physics should be provided at the SSC must be answered before the final technical design of the SSC can be completed, particularly if the eventual form of extraction would influence the magnet design. To this end, an enthusiastic group of experimentalists, theoreticians and accelerator specialists have studied this point. The accelerator physics issues were addressed by a group led by E. Colton whose report is contained in these proceedings. The physics addressable by fixed target was considered by many of the Physics area working groups and in particular by the Structure Function Group. This report is the summary of the working group which considered various SSC fixed target experiments and determined which types of beams and detectors would be required. 13 references, 5 figures.

  19. Comprehensive Assessment of the Regulons Controlled by the FixLJ-FixK2-FixK1 Cascade in Bradyrhizobium japonicum? †

    PubMed Central

    Mesa, Socorro; Hauser, Felix; Friberg, Markus; Malaguti, Emmanuelle; Fischer, Hans-Martin; Hennecke, Hauke

    2008-01-01

    Symbiotic N2 fixation in Bradyrhizobium japonicum is controlled by a complex transcription factor network. Part of it is a hierarchically arranged cascade in which the two-component regulatory system FixLJ, in response to a moderate decrease in oxygen concentration, activates the fixK2 gene. The FixK2 protein then activates not only a number of genes essential for microoxic respiration in symbiosis (fixNOQP and fixGHIS) but also further regulatory genes (rpoN1, nnrR, and fixK1). The results of transcriptome analyses described here have led to a comprehensive and expanded definition of the FixJ, FixK2, and FixK1 regulons, which, respectively, consist of 26, 204, and 29 genes specifically regulated in microoxically grown cells. Most of these genes are subject to positive control. Particular attention was addressed to the FixK2-dependent genes, which included a bioinformatics search for putative FixK2 binding sites on DNA (FixK2 boxes). Using an in vitro transcription assay with RNA polymerase holoenzyme and purified FixK2 as the activator, we validated as direct targets eight new genes. Interestingly, the adjacent but divergently oriented fixK1 and cycS genes shared the same FixK2 box for the activation of transcription in both directions. This recognition site may also be a direct target for the FixK1 protein, because activation of the cycS promoter required an intact fixK1 gene and either microoxic or anoxic, denitrifying conditions. We present evidence that cycS codes for a c-type cytochrome which is important, but not essential, for nitrate respiration. Two other, unexpected results emerged from this study: (i) specifically FixK1 seemed to exert a negative control on genes that are normally activated by the N2 fixation-specific transcription factor NifA, and (ii) a larger number of genes are expressed in a FixK2-dependent manner in endosymbiotic bacteroids than in culture-grown cells, pointing to a possible symbiosis-specific control. PMID:18689489

  20. The Fix Issue 8

    E-print Network

    Multiple Contributors

    1990-01-01

    on the edge, thrived on it, and had taken as many punishments as rewards for her actions. Leslie had long ago discovered she could only take Kira in small doses before she was overwhelmed by the sheer immensity of her conceit. But she was ready for a dose...

  1. Bare action and regularized functional integral of asymptotically safe quantum gravity

    SciTech Connect

    Manrique, Elisa; Reuter, Martin [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany)

    2009-01-15

    Investigations of quantum Einstein gravity (QEG) based upon the effective average action employ a flow equation which does not contain any ultraviolet (UV) regulator. Its renormalization group trajectories emanating from a non-Gaussian fixed point define asymptotically safe quantum field theories. A priori these theories are, somewhat unusually, given in terms of their effective rather than bare action. In this paper we construct a functional integral representation of these theories. We fix a regularized measure and show that every trajectory of effective average actions, depending on an IR cutoff only, induces an associated trajectory of bare actions which depend on a UV cutoff. Together with the regularized measure these bare actions give rise to a functional integral which reproduces the prescribed effective action when the UV cutoff is removed. In this way we are able to reconstruct the underlying microscopic (classical) system and identify its fundamental degrees of freedom and interactions. The bare action of the Einstein-Hilbert truncation is computed and its flow is analyzed as an example. Various conceptual issues related to the completion of the asymptotic safety program are discussed.

  2. The Fix Issue 8 

    E-print Network

    Multiple Contributors

    1990-01-01

    , feel compelled to write one. Please! We're sticking our necks out here, putting our naked words and pictures out for your approval. If all we get is a collective yawn, we wonder if you really want us to continue. THE FIX has little trouble getting...-fogged. Was what enough? And why so early? And would he ever fathom the man he loved? But he tightened his grip, yawning broadly. "Everything is enough." Another yawn escaped as he spoke a breath later, reassuringly. "Just enough." He felt himself drifting back...

  3. Fixed Sagittal Plane Imbalance

    PubMed Central

    Savage, Jason W.; Patel, Alpesh A.

    2014-01-01

    Study Design?Literature review. Objective?To discuss the evaluation and management of fixed sagittal plane imbalance. Methods?A comprehensive literature review was performed on the preoperative evaluation of patients with sagittal plane malalignment, as well as the surgical strategies to address sagittal plane deformity. Results?Sagittal plane imbalance is often caused by de novo scoliosis or iatrogenic flat back deformity. Understanding the etiology and magnitude of sagittal malalignment is crucial in realignment planning. Objective parameters have been developed to guide surgeons in determining how much correction is needed to achieve favorable outcomes. Currently, the goals of surgery are to restore a sagittal vertical axis?Fixed sagittal malalignment often requires complex reconstructive procedures that include osteotomy correction. Reestablishing harmonious spinopelvic alignment is associated with significant improvement in health-related quality-of-life outcome measures and patient satisfaction. PMID:25396111

  4. Action selection and action value in frontal-striatal circuits

    PubMed Central

    Seo, Moonsang; Lee, Eunjeong; Averbeck, Bruno B.

    2012-01-01

    Summary The role that frontal-striatal circuits play in normal behavior remains unclear. Two of the leading hypotheses suggest that these circuits are important for action selection or reinforcement learning. To examine these hypotheses we carried out an experiment in which monkeys had to select actions in two different task conditions. In the first (random) condition actions were selected on the basis of perceptual inference. In the second (fixed) condition the animals used reinforcement from previous trials to select actions. Examination of neural activity showed that the representation of the selected action was stronger in lateral prefrontal cortex (lPFC), and occurred earlier in the lPFC than it did in the dorsal striatum (dSTR). In contrast to this, the representation of action values, in both the random and fixed conditions was stronger in the dSTR. Thus, the dSTR contains an enriched representation of action value, but it followed frontal cortex in action selection. PMID:22681697

  5. Fixing the Standard Model

    NASA Astrophysics Data System (ADS)

    de Regt, Maurits P.

    2002-10-01

    The Standard Model is enormously predictive, but it can't be entirely correct. It includes Quantum Chromodynamics, a Yang-Mills theory with gauge group SU(3), the theory of the strong force that predicts quark properties. A basic property of SU(3) produces a zero color charge for the baryon, the sum of the red, green and blue color charges of its constituent quarks. So the three charges are not independent: r = -(g+b). Doesn't this violate the Pauli exclusion principle? If it does, fixes would require substitutes for SU(3) that provide nonzero baryon color charge numbers. The electric charge numbers of the proton and neutron are 1 and 0, and those of their quark constituents are 1/3 and 2/3, with 2 electric charge types, + and - (22-1=3). If color charge numbers for the baryon and meson were also 1 and 0, the 3 color charge types suggest multiples of 1/7 (23-1=7) for quarks, thus 1/7+2/7+4/7=1 for the baryon, and n/7+(-n/7)=0 for the meson. The nonneutral gluon numbers would be -3/7, -5/7 and -6/7 (interaction calculations make use of independent inverse operators). We present substitute mathematics for the fractions and for charge numbers in the form of integers modulo 7, complex numbers and 2x2 matrices.

  6. Gauge fixing of stringlike models via OSp(D/2)

    SciTech Connect

    Delbourgo, R.; Jarvis, P.D.; Zhang, R.B.; Thompson, G.

    1988-02-01

    Within the formalism of OSrho(D/2) supersymmetry, wherein extended BRST transformations correspond to supertranslations, the authors fix the gauge of bosonic stringlike models in the form, par. deltag = 0, ..sqrt..g = rho. The action has no propagating or interacting conformal ghosts and the Srho(2) symmetry between the ghosts is manifest.

  7. Overscreened Kondo fixed point in S = 1 spin liquid

    E-print Network

    Serbyn, Maksym

    We propose a possible realization of the overscreened Kondo impurity problem by a magnetic s = 1/2 impurity embedded in a two-dimensional S = 1 U(1) spin liquid with a Fermi surface. This problem contains an interesting ...

  8. Fixed-point Hamiltonian for a randomly driven diffusive system

    Microsoft Academic Search

    B. Schmittmann

    1993-01-01

    We consider the universal behavior of a system of interacting particles, diffusing under the influence of thermal noise and a random external field which drives the system into a non-equilibrium steady state. Critical exponents, distinct from both the Ising model and the uniformly driven system, are computed to two-loop order in an expansion around the upper critical dimension dc =

  9. Finding and characterizing unstable fixed points by controlling system dynamics

    Microsoft Academic Search

    DANIEL T. KAPLAN

    1999-01-01

    We study time series data in order to understand better the underlying dynamics of a system. Unfortunately, many time series do not contain the information we seek in an accessible form, particularly in biological systems which habitually change during the course of an experiment. By using techniques originally developed for controlling chaotic systems, one can enhance the information contained in

  10. Exact scaling solutions and fixed points for general scalar field

    Microsoft Academic Search

    Yungui Gong; Anzhong Wang; Yuan-Zhong Zhang

    2006-01-01

    We show that the most general dark energy model that possesses a scaling solution ???an is the k-essence model, which includes both of the quintessence and tachyon models. The exact scaling solutions are then derived. The potential that gives the tracking solution in which dark energy exactly tracks the background matter field is the inverse squared potential. The quintessence field

  11. C 2 FIXED POINTS OF TOPOLOGICAL HOCHSCHILD HOMOLOGY

    E-print Network

    the cyclotomic trace map trc : K(A) p # TC(A) p , which is well defined up to homotopy after p­adic completion cover of the p­completed cyclotomic trace map trc : K( â?? Z p ) p # TC(Z) p [0, #) is a homotopy

  12. FIXED POINT AND SELECTION THEOREMS IN HYPERCONVEX SPACES

    Microsoft Academic Search

    M. A. KHAMSI; W. A. KIRK; Carlos Martinez Yanez

    It is shown that a set-valued mapping T of a hyperconvex metric space M which takes values in the space of nonempty externally hyperconvex subsets of M always has a lipschitzian single valued selection T which satises d(T (x);T(y)) dH (T(x);T(y)) for allx;y2 M.( HeredH denotes the usual Hausdor distance.) This fact is used to show that the space of

  13. Fixed point free elements of prime order in permutation groups

    E-print Network

    Giudici, Michael

    . . . . . . . . . . . . . . . . . . . . 38 3.4.1 T = PSp(2m; q) for m; q even and m 6= 2. . . . . . . . . . . . . 44 3.4.2 T = PSp(4; q) for q even. . . . . . . . . . . . . . . . . . . . . . 46 3.4.3 T = PSp(4; q) for q odd

  14. Proof-Theoretic Contributions to Modal Fixed Point Logics

    E-print Network

    Jäger, Gerhard

    not have the Beth property. Information Processing Letters, to appear. 5. D. Steiner and T. Studer. Total Workshop Methods for Modalities, pages 125­143. 2005. 7. G. J¨ager, M. Kretz, and T. Studer. Canonical

  15. Fixed point theory of iterative excitation schemes in NMR

    Microsoft Academic Search

    R. Tycko; A. Pines; J. Guckenheimer

    1985-01-01

    Iterative schemes for NMR have been developed by several groups. A theoretical framework based on mathematical dynamics is described for such iterative schemes in nonlinear NMR excitation. This is applicable to any system subjected to coherent radiation or other experimentally controllable external forces. The effect of the excitation, usually a pulse sequence, can be summarized by a propagator or superpropagator

  16. On some old problems of fixed point theory

    Microsoft Academic Search

    Robert F. Brown

    1974-01-01

    It is not uncommon to begin an expository paper with the modest admission that the paper contains no new mathematics. I must make the even more modest admission that much of what I will write over­ laps other expositions; especially the excellent paper of Fadell (17). The purpose of this paper, however, is quite different from FadeH's. He described some

  17. Using a Card Trick to Illustrate Fixed Points and Stability

    ERIC Educational Resources Information Center

    Champanerkar, Jyoti; Jani, Mahendra

    2015-01-01

    Mathematical ideas from number theory, group theory, dynamical systems, and computer science have often been used to explain card tricks. Conversely, playing cards have been often used to illustrate the mathematical concepts of probability distributions and group theory. In this paper, we describe how the 21-card trick may be used to illustrate…

  18. Secure Multiparty Linear Programming Using Fixed-Point Arithmetic

    Microsoft Academic Search

    Octavian Catrina; Sebastiaan de Hoogh

    2010-01-01

    \\u000a Collaborative optimization problems can often be modeled as a linear program whose objective function and constraints combine\\u000a data from several parties. However, important applications of this model (e.g., supply chain planning) involve private data\\u000a that the parties cannot reveal to each other. Traditional linear programming methods cannot be used in this case. The problem\\u000a can be solved using cryptographic protocols

  19. Regression Fixed Point Clusters: Motivation, Consistency and Simulations

    E-print Network

    Hennig, Christian

    from the Old Faithful Geyser in the Yellowstone National Park, collected in August 1985. The duration of an eruption of the geyser is modeled here as dependent on the waiting time since the previous eruption Figure 1.1: Old Faithful Geyser data. between ``waiting'' and ``duration'', corresponding

  20. Humidity Fixed Points of Binary Saturated Aqueous Solutions

    Microsoft Academic Search

    Lewis Greenspan

    An evaluated compilation of equilibrium relative humidities in air versus temperature from pure phase to approximately 105 pascal (1 atm) in pressure is presented for 28 binary saturated aqueous solutions. The relative humidities of the solutions range from about 3 to 98 percent. Using a data base from 21 separate investigations comprising 1106 individual measurements, fits were made by the

  1. Fixed volume versus fixed pressure liquid-vapor transition

    NASA Astrophysics Data System (ADS)

    Calecki, D.; Lederer, D.; Roulet, B.; Diu, B.; Guthmann, C.

    2010-12-01

    We consider the equilibrium conditions for nucleation at the liquid-vapor transition at fixed volume in contrast to the traditional fixed pressure treatment. Significant differences appear, particularly for the stability of the diphasic states, which strongly depends on the external conditions.

  2. Unparticle actions and gauge invariance

    SciTech Connect

    Ilderton, Anton [School of Mathematics, Trinity College, Dublin 2 (Ireland)

    2009-01-15

    We show that the requirement of gauge invariance is not enough to fix the form of interactions between unparticles and gauge fields, thus revealing a wide new class of gauged unparticle actions. Our approach also allows us to construct operators which create gauge invariant colored unparticles. We discuss both their perturbative and nonperturbative properties.

  3. Fixed Asset Procedure ADMINISTRATIVE PROCEDURE

    E-print Network

    Rainforth, Emma C.

    and a useful life of more than three years; donations with an estimated or appraised market value of $5, design fees, material and supplies, construction costs. Acquisition/Addition of Fixed Assets The college and account code criteria. #12;Fixed Asset Procedure 2 ADMINISTRATIVE PROCEDURE 6/6/2011 The Purchasing

  4. 47 CFR 22.603 - 488-494 MHz fixed service in Hawaii.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false 488-494 MHz fixed service in Hawaii. 22.603 Section 22.603 Telecommunication FEDERAL...Point-To-Point Operation § 22.603 488-494 MHz fixed service in Hawaii. Before filing applications for...

  5. 47 CFR 22.603 - 488-494 MHz fixed service in Hawaii.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false 488-494 MHz fixed service in Hawaii. 22.603 Section 22.603 Telecommunication FEDERAL...Point-To-Point Operation § 22.603 488-494 MHz fixed service in Hawaii. Before filing applications for...

  6. 47 CFR 22.603 - 488-494 MHz fixed service in Hawaii.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false 488-494 MHz fixed service in Hawaii. 22.603 Section 22.603 Telecommunication FEDERAL...Point-To-Point Operation § 22.603 488-494 MHz fixed service in Hawaii. Before filing applications for...

  7. 47 CFR 22.603 - 488-494 MHz fixed service in Hawaii.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false 488-494 MHz fixed service in Hawaii. 22.603 Section 22.603 Telecommunication FEDERAL...Point-To-Point Operation § 22.603 488-494 MHz fixed service in Hawaii. Before filing applications for...

  8. 47 CFR 22.603 - 488-494 MHz fixed service in Hawaii.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false 488-494 MHz fixed service in Hawaii. 22.603 Section 22.603 Telecommunication FEDERAL...Point-To-Point Operation § 22.603 488-494 MHz fixed service in Hawaii. Before filing applications for...

  9. 9 CFR 417.3 - Corrective actions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.3 Corrective actions. (a) The written HACCP plan shall identify the corrective action...a deviation from a critical limit. The HACCP plan shall describe the corrective...

  10. Complementary actions

    PubMed Central

    Sartori, Luisa; Betti, Sonia

    2015-01-01

    Complementary colors are color pairs which, when combined in the right proportions, produce white or black. Complementary actions refer here to forms of social interaction wherein individuals adapt their joint actions according to a common aim. Notably, complementary actions are incongruent actions. But being incongruent is not sufficient to be complementary (i.e., to complete the action of another person). Successful complementary interactions are founded on the abilities: (i) to simulate another person’s movements, (ii) to predict another person’s future action/s, (iii) to produce an appropriate incongruent response which differ, while interacting, with observed ones, and (iv) to complete the social interaction by integrating the predicted effects of one’s own action with those of another person. This definition clearly alludes to the functional importance of complementary actions in the perception–action cycle and prompts us to scrutinize what is taking place behind the scenes. Preliminary data on this topic have been provided by recent cutting-edge studies utilizing different research methods. This mini-review aims to provide an up-to-date overview of the processes and the specific activations underlying complementary actions. PMID:25983717

  11. Coset space dimensional reduction and gauge fixing over the supercircle

    SciTech Connect

    Jarvis, P.D. (Dept. of Physics, Univ. of Tasmania, Box 252c, GPO, Hobart Tasmania 7001 (AU))

    1989-01-01

    In this paper the constraints of CSDR are solved for vector gauge fields over a coset space IOSp(1/2, R)/OSp(1/2, R) including supertranslations (extended BRST transformations) and ordinary translations (rotations on the circle). The gauge-fixing action incorporates standard ghost and multiplier fields (and their modes) but is nonpolynomial in an additional scalar field {phi} and its modes. There is a new {phi}-BRST invariance with respect to {phi} dependent gauge transformations, a bosonic counterpart of the usual ghost-BRST invariance. In the Abelian case, {phi} can be integrated out, leading to a formalism equivalent to ordinary covariant gauge-fixing.

  12. Reasoning About Knowledge and Action

    Microsoft Academic Search

    Robert C. Moore

    1977-01-01

    This paper discusses the problems of representing and reasoning with information about knowledge and action. The first section discusses the importance of having systems that understand the concept of knowledge, and how knowledge is related to action. Section 2 points out some of the special problems that are involved in reasoning about knowledge, and section S presents a logic of

  13. Relational Abstract Domains for the Detection of Floating-Point

    E-print Network

    Miné, Antoine

    ESOP'2004 Relational Abstract Domains for the Detection of Floating-Point Run-Time Errors Antoine-time error. Floating-Point Nowadays, embedded software use floating-point numbers instead of fixed-point. Floating-point numbers are complex, not always understood by programmers. Floating-point numbers

  14. Intel I/O, Floating point o DOS System Calls

    E-print Network

    Biagioni, Edoardo S.

    Intel I/O, Floating point o DOS System Calls o Floating point 2 #12; Floating Point o integer: 1, 2, 3, 4 o fixed point: 100.001, 100.002, 123.456 o floating point: 100 x 103 , 101 x 103 , 123 x 105 o in the floating point

  15. Automatic measurement of scanned human body in fixed posture

    Microsoft Academic Search

    Lv Bing-ru; Sun Shou qian; Lv Rui min; Zhang Zhi dong; Liu Yang

    2010-01-01

    Clothing customization needs dimensional data of human body. The 3D scanner can only get the surface data, which usually consists of a great many points and triangles. Measurement of the scanned human body automatically is a very complicated problem in practical applications. This paper proposed a simple but rapid method for automatic measurement of scanned human body in fixed posture.

  16. 47 CFR 90.467 - Dispatch points.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control § 90.467 Dispatch points...A dispatch point may be linked to the transmitter(s) being operated by private or leased...operator at a fixed control point in the system is on duty and at no other...

  17. 47 CFR 90.467 - Dispatch points.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control § 90.467 Dispatch points...A dispatch point may be linked to the transmitter(s) being operated by private or leased...operator at a fixed control point in the system is on duty and at no other...

  18. Extreme Distances in Multicolored Point Sets

    Microsoft Academic Search

    Adrian Dumitrescu; Sumanta Guha

    2002-01-01

    Given a set of n colored points in somed-dimensional Euclidean space, a bichromatic closest (resp. farthest) pair is a closest (resp. farthest) pair of points of different colors. We present efficient algorithms to main- tain both a bichromatic closest pair and a bichromatic farthest pair when the the points are fixed but they dynamically change color. We do this by

  19. Statistics of Non-Poisson Point Processes in Several Kenneth A. Brakke

    E-print Network

    Brakke, Ken

    Introduction The phrase "a random set of points in space" is in itself ambiguous. The most popular version process in addition to a fixed lattice of points, and a fixed number of random points on a finite space random point process, but there are others. It is not always justifiable to assume that a random point

  20. Point configurations that are asymmetric yet balanced

    E-print Network

    Cohn, Henry

    Abstract: A configuration of particles confined to a sphere is balanced if it is in equilibrium under all force laws (that act between pairs of points with strength given by a fixed function of distance). It is straightforward ...

  1. Action Research

    NSDL National Science Digital Library

    Becky Beran

    2010-07-01

    Defined as "any systemic inquiry conducted by teachers? for the purpose of gathering information about how their particular schools operate, how they teach, and how their students learn" (Mertler, 2009), action research is empowering and professi

  2. Mass action

    NSDL National Science Digital Library

    David Liao

    In the first part of this video, we derive the law of mass action from one example of a picture of molecular collisions. For this course, we use the "law of mass action" to refer to an idea that chemical reaction kinetic rates can be expressed using products of the abundances of reactants raised to exponents. Studying cooperativity and Hill functions in the second part of the video allows us to investigate a simple example of bistability in the third video segment.

  3. SFT Action for Separated D-branes

    E-print Network

    Longton, Matheson

    2012-01-01

    We present an action for Cubic String Field Theory with one embedding coordinate treated separately. We truncate the action at level (3,9), but unlike many other works we do not impose twist symmetry. We also allow arbitrary zero-modes for the direction considered special. Our action provides a starting point for the study of numerous configurations of D-branes.

  4. SFT Action for Separated D-branes

    E-print Network

    Matheson Longton

    2012-03-20

    We present an action for Cubic String Field Theory with one embedding coordinate treated separately. We truncate the action at level (3,9), but unlike many other works we do not impose twist symmetry. We also allow arbitrary zero-modes for the direction considered special. Our action provides a starting point for the study of numerous configurations of D-branes.

  5. Memories of Bug Fixes Sunghun Kim

    E-print Network

    Whitehead, James

    Memories of Bug Fixes Sunghun Kim Department of Computer Science University of California, Santa experience. Changes that fix bugs are especially interesting, since they record both the old buggy code and the new fixed code. This paper presents a bug finding algorithm using bug fix memories: a project

  6. Settling of fixed erythrocyte suspension droplets

    NASA Technical Reports Server (NTRS)

    Omenyi, S. N.; Snyder, R. S.

    1983-01-01

    It is pointed out that when particles behave collectively rather than individually, the fractionation of micron-size particles on the basis of size, density, and surface characteristics by centrifugation and electrophoresis is hindered. The formation and sedimentation of droplets containing particles represent an extreme example of collective behavior and pose a major problem for these separation methods when large quantities of particles need to be fractionated. Experiments are described that measure droplet sizes and settling rates for a variety of particles and droplets. Expressions relating the particle concentration in a drop to measurable quantities of the fluids and particles are developed. The number of particles in each droplet is then estimated, together with the effective droplet density. Red blood cells from different animals fixed in glutaraldehyde provide model particle groups.

  7. AN APPARATUS FOR THE APPROXIMATION OF THE TRIPLE POINT OF ARGON

    Microsoft Academic Search

    Thomas Wiandt

    SPRT calibration over the ITS-90 sub-range of 83.8058 K to 273.16 K requires measurement at three defining fixed points—the triple points of water, mercury, and argon. Cells and apparatus are commercially available for the realization of these defining fixed points. Several factors have resulted in the widespread implementation of only two of these defining fixed points—the triple points of water

  8. A Partially Gauged Fixed Hamiltonian for Scalar Field Collapse

    E-print Network

    R. G. Daghigh; J. Gegenberg; G. Kunstatter

    2007-08-09

    We derive a partially gauge fixed Hamiltonian for black hole formation via real scalar field collapse. The class of models considered includes many theories of physical interest, including spherically symmetric black holes in $D$ spacetime dimensions. The boundary and gauge fixing conditions are chosen to be consistent with generalized Painleve-Gullstrand coordinates, in which the metric is regular across the black hole future horizon. The resulting Hamiltonian is remarkably simple and we argue that it provides a good starting point for studying the quantum dynamics of black hole formation.

  9. Comparison of slurry versus fixed-bed reactor costs for indirect liquefaction applications

    SciTech Connect

    Prakash, A.; Bendale, P.G.

    1991-12-01

    This work is a comparative evaluation of slurry reactors and fixed-bed reactors, with special emphasis on cost. Relative differences between slurry reactors and fixed-bed reactors have been pointed out in previous reviews; the differences pertinent to indirect liquefaction are summarized here. Design of both types is outlined.

  10. Uncertainty of Fixed Depth Seismic Event Locations

    NASA Astrophysics Data System (ADS)

    Ballard, S.

    2006-05-01

    In seismic nuclear explosion monitoring, accurate determination of the depth of a seismic event is an extremely important but elusive goal. Important because events with hypocenters deeper than a few km can be ruled out as potential nuclear explosions, and elusive because the inherent tradeoff between the depth of an event and its origin time makes tight constraint on the depth of an event difficult if depth phases are not observed. Given these considerations, proper formulation of the uncertainty of a computed seismic event location takes on increased significance. A routine task in seismic event location is to compute a location with depth fixed at some particular depth, typically the surface of the Earth. Generally, this is done because depth is acknowledged to be poorly constrained by the available observations but one would nonetheless like an answer to the question "Assuming that the event occurred at the surface, where did it occur?" This is certainly a valid question and calculation of the answer is straightforward. Care must be exercised, however, when formulating the uncertainty of the computed fixed depth location. A naïve approach, which is frequently reported in practice, assumes that the depth of the event is known with perfect certainty, yielding an uncertainty ellipse at the desired depth. This can lead to the absurd result that a well constrained event with a 3 dimensional uncertainty that indicates that the event occurred at great depth, can have a surface, fixed depth solution with a perfectly reasonable looking uncertainty ellipse. An uncertainty estimate that better addresses the needs of the person requesting the fixed depth solution is the intersection of the 3-dimensional uncertainty boundary with the horizontal plane at the depth in question. It would be nice if the linear 3 dimensional ellipsoid could be used for this purpose, but vertical non-linearity of the Earth models generally used to compute seismic event locations makes this approach inaccurate. A far better approach would be to use the non- elliptical intersection of the surface with the 3D nonlinear uncertainty bounds determined with a grid search algorithm. Unfortunately, such a result is too computationally expensive to compute and too difficult to store in relational databases for routine work. There is an alternative approach that yields a convenient, computationally inexpensive uncertainty estimate that is comparable to the grid search results for earth models where the horizontal non-linearity is not severe. Essentially, the uncertainty ellipse is calculated as before but the dimensions of the ellipse are rescaled to reflect 3D rather than 2D uncertainty statistics, and the minimum sum squared weighted residual that is used as the reference point of the uncertainty ellipse is shifted from the minimum found at the depth of interest to the minimum found by the full 3D event location solution. For events with infinite uncertainty in the vertical direction and events whose 3D solutions occur at the depth of the fixed depth solution, the alternative uncertainty ellipse has linear dimensions about 15% larger than those calculated assuming depth is known perfectly. If the 3D solution indicates that the event could not have occurred at the depth in question, the alternative approach will return an answer of null, appropriately indicating that the event did not occur at the depth of the fixed depth solution, at the indicated confidence level. This work was supported by the United States Department of Energy under Contract DE-AC04-94AL85000. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy.

  11. Reconfigurable Block Floating Point Processing Elements in Virtex Platforms

    Microsoft Academic Search

    Guillermo Conde; Gregory W. Donohoe

    2011-01-01

    This paper describes a project undertaken to simplify the implementation of high-throughput, low-power, numerically intensive applications on Virtex platforms. The system is a pipeline composed of block floating point processing elements. These combine the advantages of fixed-point and floating-point implementations: improved data accuracy (compared to fixed-point) while keeping the hardware resources to a minimum. The design is based on the

  12. Council actions

    NASA Astrophysics Data System (ADS)

    The AGU Council and Executive Committee met on May 19, 1987, in Baltimore, Md., during the 1987 AGU Spring Meeting. All Council members except the Foreign Secretary were present. A number of section secretaries, committee chairmen, editors, interested members, and staff also attended. The primary actions of Council are outlined below.

  13. Fraction Action

    NSDL National Science Digital Library

    Miss Broadhead

    2008-03-26

    Get into action and play with fractions! Practice your fractions with this website first: Learn Yo Fractions. Read the directions! The \\"Start\\" is at the top of the page. Now, same rules, but you have to find Grampy. Find him here: Find Grampy! Want another challenge? Now the scientist Melvin needs help with his mixed-up potions! ...

  14. Fixed-dose combination therapy in hypertension: cons.

    PubMed

    Angeli, Fabio; Reboldi, Gianpaolo; Mazzotta, Giovanni; Garofoli, Marta; Ramundo, Elisa; Poltronieri, Cristina; Verdecchia, Paolo

    2012-06-01

    The goal of antihypertensive therapy is to reduce the risk associated with blood pressure elevation. Although the choice of first-line drug therapy may exert some effects on different long-term cardiovascular endpoints, randomized clinical trials and meta-analyses demonstrated that blood pressure reduction per se is the primary determinant in primary and secondary prevention. Numerous analyses carried out over the last years have repeatedly shown that many patients require the combination of two or more drugs to reach the recommended level of blood pressure control. Within this context, combination therapy with separate agents or fixed-dose combination pills offers an attractive ability to lower blood pressure more quickly, decrease adverse effects and reach blood pressure target. It is not clear whether fixed combinations of antihypertensive agents in a single tablet provide a greater benefit than the corresponding components given separately. In other words, it is not clear if the use of fixed combinations translates into a clearly improved blood pressure control and cardiovascular prevention in clinical practice. Fixed-dose combinations may simplify the treatment regimen by reducing the number of pills and may be attractive for many hypertensive patients. However, single-pill (fixed) drug combinations have some disadvantages: (i) branded fixed combinations may be more expensive than equivalent free combinations; (ii) the duration of action of individual components may not be equivalent, and this may not justify a single daily dosing of the combination; and (iii) the use of fixed combinations implies less flexibility in modifying the doses of individual components and the exposure of patients to unnecessary therapy. Moreover, should a patient develop side effects to one component, the entire combination should be discontinued and replaced by free drugs. The following three types of fixed-dose tablets have been recently proposed to give additional flexibility: (i) tablet manufactured so that each of the two drugs is placed at opposite ends of the tablet with a drug-free (inactive) layer placed in between; (ii) tablet with the combination of drugs at each end with the inactive zone in between; and (iii) tablet divided into discrete, separate segments (the two drugs are combined uniformly), which provides benefits for initial close titration and dosage adjustments. Currently, none of the fixed-dose tablets available on the market have these characteristics and, consequently, are unable to be broken to allow sufficient flexibility. PMID:22867089

  15. Brains at necropsy: to fix or not to fix?

    PubMed Central

    Katelaris, A; Kencian, J; Duflou, J; Hilton, J M

    1994-01-01

    AIM--To investigate whether routine formalin fixation of all brains coming to necropsy increases the rate of detection of brain abnormalities relative to either selective formalin fixation of brain tissue or fresh dissection of all brain tissue at the time of post mortem examination. METHODS--A retrospective study of 300 medicolegal necropsies was performed. One hundred cases were examined by doctors with little or no formal training in necropsy pathology. One hundred cases were examined by forensic pathologists, who used their discretion as to whether to fix the brain in formalin. A further 100 cases were examined by neuropathologists; all the brains had already been fixed at the time of necropsy. RESULTS--When examined by doctors with little or no formal necropsy pathology training, only 15% of brains were found to be abnormal. In the case of selective fixation, 33% were found to be abnormal. When there was obligatory fixation of all brains, 51% of all brains were found to be abnormal. CONCLUSIONS--It is concluded that formalin fixation of the whole brain at the time of necropsy, followed by detailed examination of the brain by a neuropathologist, significantly increases the detection rate of brain pathology at necropsy. PMID:7962624

  16. Surgical Correction of Fixed Kyphosis

    PubMed Central

    Cho, Woo-Jin; Kang, Chang-Nam; Park, Ye-Soo; Kim, Hyoung-Jin

    2007-01-01

    Study Design A retrospective review was carried out on 23 patients with rigid fixed kyphosis who underwent surgical correction for their deformity. Purpose To report the results of surgical correction of fixed kyphosis according to the surgical approaches or methods. Overview of Literature Surgical correction of fixed kyphosis is more dangerous than the correction of any other spinal deformity because of the high incidence of paraplegia. Methods There were 12 cases of acute angular kyphosis (6 congenital, 6 healed tuberculosis) and 11 cases of round kyphosis (10 ankylosing spondylitis, 1 Scheuermann's kyphosis). Patients were excluded if their kyphosis was due to active tuberculosis, fractures, or degenerative lumbar changes. Operative procedures consisted of anterior, posterior and combined approaches with or without total vertebrectomy. Anterior procedure only was performed in 2 cases, while posterior procedure only was performed in 8 cases. Combined procedures were used in 13 cases, including 4 total vertebrectomies. Results The average kyphotic angle was 71.8° preoperatively, 31.0° postoperatively, and the average final angle was 39.2°. Thus, the correction rate was 57% and the correction loss rate was 12%. In acute angular kyphosis, correction rate of an anterior procedure only was 71%, correction rate of the combined procedures without total vertebrectomy was 49% and correction rate of the combined procedures with total vertebrectomy was 60%. In round kyphosis, correction rate of posterior procedure only was 65% and correction rate of combined procedures was 59%. The clinical results according to the Kirkaldy-Willis scale demonstrated 17 excellent outcomes, 5 good outcomes and one poor outcome. Conclusions Our data indicates that the combined approach and especially the total vertebrectomy showed the safety and the greatest correction rate if acute angular kyphosis was greater than 60 degrees. PMID:20411147

  17. Global Positioning System Antenna Fixed Height Tripod Adapter

    NASA Technical Reports Server (NTRS)

    Dinardo, Steven J.; Smith, Mark A.

    1997-01-01

    An improved Global Positioning em antenna adaptor allows fixed antenna height measurements by removably attaching an adaptor plate to a conventional surveyor's tripod. Antenna height is controlled by an antenna boom which is a fixed length rod. The antenna is attached to one end of the boom. The opposite end of the boom tapers to a point sized to fit into a depression at the center of survey markers. The boom passes through the hollow center of a universal ball joint which is mounted at the center of the adaptor plate so that the point of the rod can be fixed in the marker's central depression. The mountains of the ball joint allow the joint to be moved horizontally in any direction relative to the tripod. When the ball joint is moved horizontally, the angle between the boom and the vertical changes because the boom's position is fixed at its lower end. A spirit level attached to the rod allows an operator to determine when the boom is plumb. The position of the ball joint is adjusted horizontally until the boom is plumb. At that time the antenna is positioned exactly over the center of the monument and the elevation of the antenna is precisely set by the length of the boom.

  18. 8.EE Fixing the Furnace

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Ivan’s furnace has quit working during the coldest part of the year, and he is eager to get it fixed. He decides to call some mechanics and furnace spe...

  19. Tipping Points

    NASA Astrophysics Data System (ADS)

    Hansen, J.

    2007-12-01

    A climate tipping point, at least as I have used the phrase, refers to a situation in which a changing climate forcing has reached a point such that little additional forcing (or global temperature change) is needed to cause large, relatively rapid, climate change. Present examples include potential loss of all Arctic sea ice and instability of the West Antarctic and Greenland ice sheets. Tipping points are characterized by ready feedbacks that amplify the effect of forcings. The notion that these may be runaway feedbacks is a misconception. However, present "unrealized" global warming, due to the climate system's thermal inertia, exacerbates the difficulty of avoiding global warming tipping points. I argue that prompt efforts to slow CO2 emissions and absolutely reduce non-CO2 forcings are both essential if we are to avoid tipping points that would be disastrous for humanity and creation, the planet as civilization knows it.

  20. Actionable Nuggets

    PubMed Central

    McColl, Mary Ann; Aiken, Alice; Smith, Karen; McColl, Alexander; Green, Michael; Godwin, Marshall; Birtwhistle, Richard; Norman, Kathleen; Brankston, Gabrielle; Schaub, Michael

    2015-01-01

    Abstract Objective To present the results of a pilot study of an innovative methodology for translating best evidence about spinal cord injury (SCI) for family practice. Design Review of Canadian and international peer-reviewed literature to develop SCI Actionable Nuggets, and a mixed qualitative-quantitative evaluation to determine Nuggets’ effect on physician knowledge of and attitudes toward patients with SCI, as well as practice accessibility. Setting Ontario, Newfoundland, and Australia. Participants Forty-nine primary care physicians. Methods Twenty Actionable Nuggets (pertaining to key health issues associated with long-term SCI) were developed. Nugget postcards were mailed weekly for 20 weeks to participating physicians. Prior knowledge of SCI was self-rated by participants; they also completed an online posttest to assess the information they gained from the Nugget postcards. Participants’ opinions about practice accessibility and accommodations for patients with SCI, as well as the acceptability and usefulness of Nuggets, were assessed in interviews. Main findings With Actionable Nuggets, participants’ knowledge of the health needs of patients with SCI improved, as knowledge increased from a self-rating of fair (58%) to very good (75%) based on posttest quiz results. The mean overall score for accessibility and accommodations in physicians’ practices was 72%. Participants’ awareness of the need for screening and disease prevention among this population also increased. The usefulness and acceptability of SCI Nugget postcards were rated as excellent. Conclusion Actionable Nuggets are a knowledge translation tool designed to provide family physicians with concise, practical information about the most prevalent and pressing primary care needs of patients with SCI. This evidence-based resource has been shown to be an excellent fit with information consumption processes in primary care. They were updated and adapted for distribution by the Canadian Medical Association to approximately 50 000 primary care physicians in Canada, in both English and French.