First and Second Order Convex Sweeping Processes in Reflexive Smooth Banach Spaces
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In this paper we establish new characterizations of the normal cone of closed convex sets in reflexive smooth Banach spaces and then we use those results to prove the existence of solutions for first order convex sweeping processes and their variants in reflexive smooth Banach spaces. The case of second order convex sweeping processes is also studied. (author)
Mixed Variational-Like Inequality for Fuzzy Mappings in Reflexive Banach Spaces
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Petrot Narin
2009-01-01
Full Text Available Some existence theorems for the mixed variational-like inequality for fuzzy mappings (FMVLIP in a reflexive Banach space are established. Further, the auxiliary principle technique is used to suggest a novel and innovative iterative algorithm for computing the approximate solution. Consequently, not only the existence of solutions of the FMVLIP is shown, but also the convergence of iterative sequences generated by the algorithm is also proven. The results proved in this paper represent an improvement of previously known results.
Existence of fixed points for mappings on a ball of a reflexive and separable Banach space
Viola, Gabriella; Delbosco, Domenico
2006-01-01
Let X be a reflexive and separable Banach space, Br denotes the closed ball of radius r in X and f : Br \\to X a continuous mapping in the weak topology of X satisfying the following boundary condition \\vert fx \\vert < \\vert fx - x \\vert + \\vert x \\vert for all x ? \\partial B_r. This paper contains some theorems of existence of a fixed point under the above boundary condition. Moreover a connection with Leray Schauder nonlinear alternative.
Akagi, Goro
We prove the existence of solutions of the Cauchy problem for the doubly nonlinear evolution equation: dv(t)/dt+??(u(t))?f(t), v(t)???(u(t)), 0Hilbert space H (respectively, reflexive Banach space V) into (-?,+?] and f is given. To do so, we suppose that V?H?H?V compactly and densely, and we also assume smoothness in t, boundedness and coercivity of ? in an appropriate sense, but use neither strong monotonicity nor boundedness of ??. The method of our proof relies on approximation problems in H and a couple of energy inequalities. We also treat the initial-boundary value problem of a non-autonomous degenerate elliptic-parabolic problem.
International Nuclear Information System (INIS)
Let E be a real reflexive Banach space with uniformly Gateaux differentiable norm. Let K be a nonempty closed convex subset of E. Suppose that every nonempty closed convex bounded subset of K has the fixed point property for nonexpansive mappings. Let T1, T2, ..., TN be a family of nonexpansive self-mappings of K, with F := intersectioni=1N Fix(Ti) ? 0, F = Fix(TNTN-1... T1) = Fix(T1TN ... T2) = ... Fix(TN-1TN-2... T1TN). Let { ?n} be a sequence in (0, 1) satisfying the following conditions: C1 : lim ?n 0; C2 : ? ?n = ? . For a fixed ? element of (0, 1), define Sn : K ? K by Snx := (1 - ? )x + ?Tnx for all x element of K where Tn = Tn mod N. For arbitrary fixed u, x0 element of K, let B := { x element of K : TNTN-1... T1x ?x+(1- ?)u, for some ? > 1} be bounded and let the sequence {xn} be defined iteratively by xn+1 ?n+1u + (1 - ?n+1 )Sn+1xn, for n ? 0. Assume that lim n?? vertical bar vertical bar Tnxn - Tn+1 xn vertical bar vertical bar = 0. Then, {xn} converges strongly to a common fixed point of the family T1, T2, ..., TN. Convergence theorem is also proved for non-self maps. (author)
Klotz, Michael
2009-01-01
A Banach symmetric space in the sense of O. Loos is a smooth Banach manifold $M$ endowed with a multiplication map $\\mu\\colon M \\times M \\to M$ such that each left multiplication map $\\mu_x := \\mu(x,\\cdot)$ (with $x \\in M$) is an involutive automorphism of $(M,\\mu)$ with the isolated fixed point $x$. We show that morphisms of Lie triple systems of symmetric spaces can be uniquely integrated provided the first manifold is 1-connected. The problem is attacked by showing that a continuous linear map between tangent spaces of affine Banach manifolds with parallel torsion and curvature is integrable to an affine map if it intertwines the torsion and curvature tensors provided the first manifold is 1-connected and the second one is geodesically complete. Further, we show that the automorphism group of a connected Banach symmetric space $M$ can be turned into a Banach-Lie group acting smoothly and transitively on $M$. In particular, $M$ is a Banach homogeneous space.
Multipliers of Banach valued weighted function spaces
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Serap Öztop
2000-10-01
Full Text Available We generalize Banach valued spaces to Banach valued weighted function spaces and study the multipliers space of these spaces. We also show the relationship between multipliers and tensor product of Banach valued weighted function spaces.
On unconditionally saturated Banach spaces
Dodos, Pandelis
2008-01-01
We prove a structural property of the class of unconditionally saturated separable Banach spaces. We show, in particular, that for every analytic set $\\aaa$, in the Effros-Borel space of subspaces of $C[0,1]$, of unconditionally saturated separable Banach spaces, there exists an unconditionally saturated Banach space $Y$, with a Schauder basis, that contains isomorphic copies of every space $X$ in the class $\\aaa$.
Dzamonja, Mirna; Shelah, Saharon
1998-01-01
Suppose that lambda = lambda^{ aleph_0, and we are considering a theory T. We give a criterion on T which is sufficient for the consistent existence of a universal model of T of size lambda^+ for models of T of size lambda^+. In fact, we work more generally with abstract elementary classes. We apply this criterion to show that for such lambda it is consistent to have a universal Banach space over R (or C) of density lambda^+, under isometries, while 2^{lambda}=2^{lambda^+}>> lambda^{++} . We further observe that for such lambda, for any fixed mu > lambda^+ regular with mu = mu^{lambda^+}, it is consistent that 2^lambda = mu and there is no normed vector space over Q of size < mu which is universal for normed vector spaces over Q of dimension lambda^+ under the notion of embedding h which specifies (a,b) such that | h(x) |/ | x | in (a,b) for all x . The criterion for the consistent existence of universals which is mentioned in the previous paragraph, applies to some other theories as well, like triangle-fr...
Existence of zeros for operators taking their values in the dual of a Banach space
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Ricceri Biagio
2004-01-01
Full Text Available Using continuous selections, we establish some existence results about the zeros of weakly continuous operators from a paracompact topological space into the dual of a reflexive real Banach space.
Infimal convolution in Efimov-Ste?kin Banach spaces.
Czech Academy of Sciences Publication Activity Database
Fabian, Marián
2008-01-01
Ro?. 339, ?. 1 (2008), s. 735-739. ISSN 0022-247X R&D Projects: GA AV ?R(CZ) IAA100190610 Institutional research plan: CEZ:AV0Z10190503 Keywords : reflexive Banach space * Kadec- Klee norm * infimal convolution Subject RIV: BA - General Mathematics Impact factor: 1.046, year: 2008
Isometries on Banach spaces function spaces
Fleming, Richard J
2002-01-01
Fundamental to the study of any mathematical structure is an understanding of its symmetries. In the class of Banach spaces, this leads naturally to a study of isometries-the linear transformations that preserve distances. In his foundational treatise, Banach showed that every linear isometry on the space of continuous functions on a compact metric space must transform a continuous function x into a continuous function y satisfying y(t) = h(t)x(p(t)), where p is a homeomorphism and |h| is identically one.Isometries on Banach Spaces: Function Spaces is the first of two planned volumes that survey investigations of Banach-space isometries. This volume emphasizes the characterization of isometries and focuses on establishing the type of explicit, canonical form given above in a variety of settings. After an introductory discussion of isometries in general, four chapters are devoted to describing the isometries on classical function spaces. The final chapter explores isometries on Banach algebras.This treatment p...
Reflexivity of the isometry group of some classical spaces
Sanchez, Felix Cabello; Molnar, Lajos
2001-01-01
We investigate the reflexivity of the isometry group and the automorphism group of some important metric linear spaces and algebras. The paper consists of the following sections: 1. Preliminaries. 2. Sequence spaces. 3. Spaces of measurable functions. 4. Hardy spaces. 5. Banach algebras of holomorphic functions. 6. Frechet algebras of holomorphic functions. 7. Spaces of continuous functions.
Isometric embeddings of compact spaces into Banach spaces
Dutrieux, Yves; Lancien, Gilles
2008-01-01
We show the existence of a compact metric space $K$ such that whenever $K$ embeds isometrically into a Banach space $Y$, then any separable Banach space is linearly isometric to a subspace of $Y$. We also address the following related question: if a Banach space $Y$ contains an isometric copy of the unit ball or of some special compact subset of a separable Banach space $X$, does it necessarily contain a subspace isometric to $X$? We answer positively this question when $X$ ...
On Peano's theorem in Banach spaces
Hájek, Petr
2009-01-01
We show that if $X$ is an infinite-dimensional separable Banach space (or more generally a Banach space with an infinite-dimensional separable quotient) then there is a continuous mapping $f\\colon X\\to X$ such that the autonomous differential equation $x'=f(x)$ has no solution at any point.
Topics in Banach space integration
Schwabik, Štefan
2005-01-01
The relatively new concepts of the Henstock-Kurzweil and McShane integrals based on Riemann type sums are an interesting challenge in the study of integration of Banach space-valued functions. This timely book presents an overview of the concepts developed and results achieved during the past 15 years. The Henstock-Kurzweil and McShane integrals play the central role in the book. Various forms of the integration are introduced and compared from the viewpoint of their generality. Functional analysis is the main tool for presenting the theory of summation gauge integrals.
Diffeomorphisms with Banach space domains
Zampieri, Gaetano
2012-01-01
Our basic element is a $C^1$ mapping $f:X\\to Y$, with $X,Y$ Banach spaces, and with derivative everywhere invertible. So $f$ is a local diffeomorphism at every point. The aim of this paper is to find a sufficient condition for $f$ to be injective, and so a global diffeomorphism $X\\to f(X)$, and a sufficient condition for $f$ to be bijective and so a global diffeomorphism onto $Y$. This last condition is also necessary in the particular case $X=Y=\\R^n$. In these theorems the key role is played by nonnegative auxiliary scalar coercive functions.
Banach spaces of analytic functions
Hoffman, Kenneth
2014-01-01
A classic of pure mathematics, this advanced graduate-level text explores the intersection of functional analysis and analytic function theory. Close in spirit to abstract harmonic analysis, it is confined to Banach spaces of analytic functions in the unit disc.The author devotes the first four chapters to proofs of classical theorems on boundary values and boundary integral representations of analytic functions in the unit disc, including generalizations to Dirichlet algebras. The fifth chapter contains the factorization theory of Hp functions, a discussion of some partial extensions of the f
Condensation rank of injective Banach spaces
Gazor, Majid
2011-01-01
The condensation rank associates any topological space with a unique ordinal number. In this paper we prove that the condensation rank of any infinite dimensional injective Banach space is equal to or greater than the first uncountable ordinal number.
On Uniformly finitely extensible Banach spaces
Castillo, Jesu?s M. F.; Ferenczi, Valentin; Moreno, Yolanda
2013-01-01
We continue the study of Uniformly Finitely Extensible Banach spaces (in short, UFO) initiated in Moreno-Plichko, \\emph{On automorphic Banach spaces}, Israel J. Math. 169 (2009) 29--45 and Castillo-Plichko, \\emph{Banach spaces in various positions.} J. Funct. Anal. 259 (2010) 2098-2138. We show that they have the Uniform Approximation Property of Pe\\l czy\\'nski and Rosenthal and are compactly extensible. We will also consider their connection with the automorphic space probl...
Weakly compact approximation in Banach spaces
Odell, Edward; Tylli, Hans-olav
2003-01-01
The Banach space $E$ has the weakly compact approximation property (W.A.P. for short) if there is a constant $C 0$ there is a weakly compact operator $V: E \\to E$ satisfying $\\sup_{x\\in D} || x - Vx || < \\epsilon$ and $|| V|| \\leq C$. We give several examples of Banach spaces both with and without this approximation property. Our main results demonstrate that the James-type spaces from a general class...
A class of Banach spaces with few non strictly singular operators
Argyros, S A; Todorcevic, S
2003-01-01
We construct a family $(\\mathcal{X}_\\al)_{\\al\\le \\omega_1}$ of reflexive Banach spaces with long transfinite bases but with no unconditional basic sequences. In our spaces $\\mathcal{X}_\\al$ every bounded operator $T$ is split into its diagonal part $D_T$ and its strictly singular part $S_T$.
A pythagorean approach in Banach spaces
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available Let X be a Banach space and S ( X = { x ? X , ? x ? = 1 } be the unit sphere of X . Parameters E ( X = sup ? { ? ( x , x ? S ( X } , e ( X = inf ? { ? ( x , x ? S ( X } , F ( X = sup ? { ? ( x , x ? S ( X } , and f ( X = inf ? { ? ( x , x ? S ( X } , where ? ( x = sup ? { ? x + y ? 2 + ? x ? y ? 2 , y ? S ( X } and ? ( x = inf ? { ? x + y ? 2 + ? x ? y ? 2 , y ? S ( X } are introduced and studied. The values of these parameters in the l p spaces and function spaces L p [ 0 , 1 ] are estimated. Among the other results, we proved that a Banach space X with E ( X < 8 , or 2$"> f ( X > 2 is uniform nonsquare; and a Banach space X with E ( X < 5 , or frac{32}{9}$"> f ( X > 32 / 9 has uniform normal structure.
Completely positive linear operators for Banach spaces
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Mingze Yang
1994-03-01
Full Text Available Using ideas of Pisier, the concept of complete positivity is generalized in a different direction in this paper, where the Hilbert space Ã¢Â„Â‹ is replaced with a Banach space and its conjugate linear dual. The extreme point results of Arveson are reformulated in this more general setting.
Banach spaces of vector-valued functions
Cembranos, Pilar
1997-01-01
"When do the Lebesgue-Bochner function spaces contain a copy or a complemented copy of any of the classical sequence spaces?" This problem and the analogous one for vector- valued continuous function spaces have attracted quite a lot of research activity in the last twenty-five years. The aim of this monograph is to give a detailed exposition of the answers to these questions, providing a unified and self-contained treatment. It presents a great number of results, methods and techniques, which are useful for any researcher in Banach spaces and, in general, in Functional Analysis. This book is written at a graduate student level, assuming the basics in Banach space theory.
Three-space problems in Banach space theory
Castillo, Jesús M F
1997-01-01
This book on Banach space theory focuses on what have been called three-space problems. It contains a fairly complete description of ideas, methods, results and counterexamples. It can be considered self-contained, beyond a course in functional analysis and some familiarity with modern Banach space methods. It will be of interest to researchers for its methods and open problems, and to students for the exposition of techniques and examples.
Factorizations of EP Banach space operators and EP Banach algebra elements
Boasso, Enrico
2013-01-01
EP Banach space operators and EP Banach algebra elements are characterized using different kinds of factorizations. The results obtained generalize well-known characterizations of EP matrices, EP Hilbert space operators and EP $C^*$-algebra elements. Furthermore, new results that hold in these contexts are presented.
Topological Vector-Space Valued Cone Banach Spaces
Nayyar Mehmood; Akbar Azam; Suzana Aleksic
2014-01-01
In this paper we introduce the notion of tvs-cone normed spaces, discuss related topological concepts and characterize the tvs-cone norm in various directions. We construct generalize locally convex tvs generated by a family of tvs-cone seminorms. The class of weak contractions properly includes large classes of highly applicable contractions like Banach, Kannan, Chatterjea and quasi etc. We prove fixed point results in tvs-cone Banach spaces for nonexpansive self mappings and self/non-self w...
Geometric, spectral and asymptotic properties of averaged products of projections in Banach spaces
Badea, Catalin; Lyubich, Yuri I.
2010-01-01
According to the von Neumann-Halperin and Lapidus theorems, in a Hilbert space the iterates of products or, respectively, of convex combinations of orthoprojections are strongly convergent. We extend these results to the iterates of convex combinations of products of some projections in a complex Banach space. The latter is assumed uniformly convex or uniformly smooth for the orthoprojections, or reflexive for more special projections, in particular, for the hermitian ones. ...
Introduction to Banach spaces and algebras
Allan, Graham
2010-01-01
Banach spaces and algebras are a key topic of pure mathematics. Graham Allan's careful and detailed introductory account will prove essential reading for anyone wishing to specialise in functional analysis and is aimed at final year undergraduates or masters level students. Based on the author's lectures to fourth year students at Cambridge University, the book assumes knowledge typical of first degrees in mathematics, including metric spaces, analytic topology, and complexanalysis. However, readers are not expected to be familiar with the Lebesgue theory of measure and integration.The text be
Nonlinear evolution equations on Banach space
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N. U. Ahmed
1991-01-01
Full Text Available In this paper we consider the questions of existence and uniqueness of solutions of certain semilinear and quasilinear evolution equations on Banach space. We consider both deterministic and stochastic systems. The approach is based on semigroup theory and fixed point theorems. Our results allow the nonlinear perturbations in all the semilinear problems to be bounded or unbounded with reference to the base space, thereby increasing the scope for applications to partial differential equations. Further, quasilinear stochastic evolution equations seemingly have never been considered in the literature.
Discretization of variational regularization in Banach spaces
Pöschl, Christiane; Resmerita, Elena; Scherzer, Otmar
2010-10-01
Consider a nonlinear ill-posed operator equation F(u) = y, where F is defined on a Banach space X. In this paper we analyze finite-dimensional variational regularization, which takes into account operator approximations and noisy data. As shown in the literature, depending on the setting, convergence of the regularized solutions of the finite-dimensional problems can be with respect to the strong or just a weak topology. In this paper our contribution is twofold. First, we derive convergence rates in terms of Bregman distances in the convex regularization setting under appropriate sourcewise representation of a solution of the equation. Secondly, for particular regularization realizations in nonseparable Banach spaces, we discuss the finite-dimensional approximations of the spaces and the type of convergence, which is needed for the convergence analysis. These considerations lay the fundament for efficient numerical implementation. In particular, we emphasize on the space X of finite total variation functions and analyze in detail the cases when X is the space of the functions of finite bounded deformation and the L?-space. The latter two settings are of interest in numerous problems arising in optimal control, machine learning and engineering.
Discretization of variational regularization in Banach spaces
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Consider a nonlinear ill-posed operator equation F(u) = y, where F is defined on a Banach space X. In this paper we analyze finite-dimensional variational regularization, which takes into account operator approximations and noisy data. As shown in the literature, depending on the setting, convergence of the regularized solutions of the finite-dimensional problems can be with respect to the strong or just a weak topology. In this paper our contribution is twofold. First, we derive convergence rates in terms of Bregman distances in the convex regularization setting under appropriate sourcewise representation of a solution of the equation. Secondly, for particular regularization realizations in nonseparable Banach spaces, we discuss the finite-dimensional approximations of the spaces and the type of convergence, which is needed for the convergence analysis. These considerations lay the fundament for efficient numerical implementation. In particular, we emphasize on the space X of finite total variation functions and analyze in detail the cases when X is the space of the functions of finite bounded deformation and the L?-space. The latter two settings are of interest in numerous problems arising in optimal control, machine learning and engineering
Unbounded operators on Banach spaces over the quaternion field
Ludkovsky, S. V.
2004-01-01
Resolvents of quasi-linear operators and operator algebras in Banach spaces over the quaternion field are investigated. Spectral theory of unbounded nonlinear operators in quaternion Banach spaces is studied. Strongly continuous semigroups of quaternion quasi-linear operators are investigated and the polar decomposition theorem for them is proved.
Banach spaces adapted to Anosov systems
Gouezel, S; Gouezel, Sebastien; Liverani, Carlangelo
2004-01-01
We study the spectral properties of the Ruelle-Perron-Frobenius operator associated to an Anosov map on classes of functions with high smoothness. To this end we construct anisotropic Banach spaces of distributions on which the transfer operator has a large spectral gap. In the C^\\infty case, the spectral radius is arbitrarily small, which yields a description of the correlations with arbitrary precision. Moreover, we obtain sharp spectral stability results for deterministic and random perturbations. In particular, we obtain differentiability results for spectral data (which imply differentiability of the SRB measure, the variance for the CLT, the rates of decay for smooth observable, etc.).
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Ofoedu EU
2008-01-01
Full Text Available Abstract Let be a real reflexive and strictly convex Banach space which has a uniformly Gâteaux differentiable norm and be a closed convex nonempty subset of . Strong convergence theorems for approximation of a common zero of a countably infinite family of -accretive mappings from to are proved. Consequently, we obtained strong convergence theorems for a countably infinite family of pseudocontractive mappings.
Banach frames for multivariate alpha-modulation spaces
DEFF Research Database (Denmark)
Borup, Lasse; Nielsen, Morten
2006-01-01
The ?-modulation spaces [$Mathematical Term$], form a family of spaces that include the Besov and modulation spaces as special cases. This paper is concerned with construction of Banach frames for ?-modulation spaces in the multivariate setting. The frames constructed are unions of independent Riesz sequences based on tensor products of univariate brushlet functions, which simplifies the analysis of the full frame. We show that the multivariate ?-modulation spaces can be completely characterized by the Banach frames constructed. Udgivelsesdato: SEP 15
On algebras which are inductive limits of Banach spaces
Alpay, Daniel; Salomon, Guy
2013-01-01
We introduce algebras which are inductive limits of Banach spaces and carry inequalities which are counterparts of the inequality for the norm in a Banach algebra. We then define an associated Wiener algebra, and prove the corresponding version of the well-known Wiener theorem. Finally, we consider factorization theory in these algebra, and in particular, in the associated Wiener algebra.
Generalized quasi-Banach sequence spaces and measures of noncompactness
Scientific Electronic Library Online (English)
EDUARDO B., SILVA; DIOCESAR L., FERNANDEZ; LUDMILA, NIKOLOVA.
2013-06-01
Full Text Available Dado 0 [...] ão compacidade de Hausdorff. Como uma aplicação, conjuntos compactos nos espa, cos de interpolação s – ?, de um par quase-Banach são estudados. Abstract in english Given 0 [...] As an application, compact sets in s – ? -interpolation spaces of a quasi-Banach couple are studied.
A Dichotomy for Ordinary Differential Equations in a Banach Space
Kiskinov, Hristo; Kostadinov, Stepan
2010-01-01
A dichotomysimilar property for a class of homogeneous differential equations in an arbitrary Banach space is introduced. By help of them, existence of quasi bounded solutions of the appropriate nonhomogeneous equation is proved.
On second order impulsive functional differential equations in Banach spaces
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M. Benchohra
2002-01-01
Full Text Available In this paper, a fixed point theorem due to Schaefer is used to investigate the existence of solutions for second order impulsive functional differential equations in Banach spaces.
Stochastic evolution equations in UMD Banach spaces
van Neerven, J M A M; Weis, L
2008-01-01
We discuss existence, uniqueness, and space-time H\\"older regularity for solutions of the parabolic stochastic evolution equation dU(t) = (AU(t) + F(t,U(t))) dt + B(t,U(t)) dW_H(t), t\\in [0,\\Tend], U(0) = u_0, where $A$ generates an analytic $C_0$-semigroup on a UMD Banach space $E$ and $W_H$ is a cylindrical Brownian motion with values in a Hilbert space $H$. We prove that if the mappings $F:[0,T]\\times E\\to E$ and $B:[0,T]\\times E\\to \\mathscr{L}(H,E)$ satisfy suitable Lipschitz conditions and $u_0$ is $\\F_0$-measurable and bounded, then this problem has a unique mild solution, which has trajectories in $C^\\l([0,T];\\D((-A)^\\theta)$ provided $\\lambda\\ge 0$ and $\\theta\\ge 0$ satisfy $\\l+\\theta<\\frac12$. Various extensions of this result are given and the results are applied to parabolic stochastic partial differential equations.
Geometric, spectral and asymptotic properties of averaged products of projections in Banach spaces
Badea, Catalin
2010-01-01
According to the von Neumann-Halperin and Lapidus theorems, in a Hilbert space the iterates of products or, respectively, of convex combinations of orthoprojections are strongly convergent. We extend these results to the iterates of convex combinations of products of some projections in a complex Banach space. The latter is assumed uniformly convex or uniformly smooth for the orthoprojections, or reflexive for more special projections, in particular, for the hermitian ones. In all cases the proof of convergence is based on a known criterion in terms of the boundary spectrum.
Tauberian theorems for generalized functions with values in Banach spaces
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Drozhzhinov, Yu N; Zav' yalov, B I [Steklov Mathematical Institute, Russian Academy of Sciences (Russian Federation)
2002-08-31
We state and prove Tauberian theorems of a new type. In these theorems we give sufficient conditions under which the values of a generalized function (distribution) that are assumed to lie in a locally convex topological space actually belong to some narrower (Banach) space. These conditions are stated in terms of 'general class estimates' for the standard average of this generalized function with a fixed kernel belonging to a space of test functions. The applications of these theorems are based, in particular, on the fact that asymptotical (and some other) properties of the generalized functions under investigation can be described in terms of membership of certain Banach spaces. We apply these theorems to the study of asymptotic properties of solutions of the Cauchy problem for the heat equation in the class of generalized functions of small growth (tempered distributions), and to the study of Banach spaces of Besov-Nikol'skii type.
Tauberian theorems for generalized functions with values in Banach spaces
International Nuclear Information System (INIS)
We state and prove Tauberian theorems of a new type. In these theorems we give sufficient conditions under which the values of a generalized function (distribution) that are assumed to lie in a locally convex topological space actually belong to some narrower (Banach) space. These conditions are stated in terms of 'general class estimates' for the standard average of this generalized function with a fixed kernel belonging to a space of test functions. The applications of these theorems are based, in particular, on the fact that asymptotical (and some other) properties of the generalized functions under investigation can be described in terms of membership of certain Banach spaces. We apply these theorems to the study of asymptotic properties of solutions of the Cauchy problem for the heat equation in the class of generalized functions of small growth (tempered distributions), and to the study of Banach spaces of Besov-Nikol'skii type
Metric embeddings bilipschitz and coarse embeddings into Banach spaces
Ostrovskii, Mikhail I
2013-01-01
Embeddings of discrete metric spaces into Banach spaces recently became an important tool in computer science and topology. The book will help readers to enter and to work in this very rapidly developing area having many important connections with different parts of mathematics and computer science. The purpose of the book is to present some of the most important techniques and results, mostly on bilipschitz and coarse embeddings. The topics include embeddability of locally finite metric spaces into Banach spaces is finitely determined, constructions of embeddings, distortion in terms of Poinc
Banach Contraction Principle for Cyclical Mappings on Partial Metric Spaces
Abdeljawad, Thabet; Alzabut, Jehad O.; Mukheimer, Aiman; Zaidan, Younes
2011-01-01
In this paper, we prove that the Banach contraction principle proved by S. G. Matthews in 1994 on 0--complete partial metric spaces can be extended to cyclical mappings. However, the generalized contraction principle proved by D. Ili\\'{c}, V. Pavlovi\\'{c} and V. Rako\\u{c}evi\\'{c} in "Some new extensions of Banach's contraction principle to partial metric spaces, Appl. Math. Lett. 24 (2011), 1326--1330" on complete partial metric spaces can not be extended to cyclical mapping...
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E. U. Ofoedu
2008-03-01
Full Text Available Let E be a real reflexive and strictly convex Banach space which has a uniformly GÃƒÂ¢teaux differentiable norm and C be a closed convex nonempty subset of E. Strong convergence theorems for approximation of a common zero of a countably infinite family of m-accretive mappings from C to E are proved. Consequently, we obtained strong convergence theorems for a countably infinite family of pseudocontractive mappings.
Banach spaces and descriptive set theory selected topics
Dodos, Pandelis
2010-01-01
This volume deals with problems in the structure theory of separable infinite-dimensional Banach spaces, with a central focus on universality problems. This topic goes back to the beginnings of the field and appears in Banach's classical monograph. The novelty of the approach lies in the fact that the answers to a number of basic questions are based on techniques from Descriptive Set Theory. Although the book is oriented on proofs of several structural theorems, in the main text readers will also find a detailed exposition of numerous “intermediate” results which are interesting in their own right and have proven to be useful in other areas of Functional Analysis. Moreover, several well-known results in the geometry of Banach spaces are presented from a modern perspective.
Stochastic Integration in Banach Spaces using a product structure with partial order
Bierkens, Joris; Gaans, Onno
2009-01-01
Using a multiplicative structure (for example that of a Banach algebra) and a partial order we construct a weak version of a Banach space valued stochastic integral with respect to square integrable martingales.
Coincidence and fixed point theorems in metric and Banach spaces
Khan, Mohammad S.; Jeong Sheok Ume; Zeqing Liu
2001-01-01
We prove some coincidence and fixed point theorems for generalized (ÃÂ•,f)-contractive type and f-nonexpansive type multivalued and singlevalued mappings in metric and Banach spaces, respectively. Our results extend, improve, and unify a few known results due to Browder, Browder and Petryshyn, Chang, Huang, and Cho, Husain and Latif, Husain and Tarafdar, and Karlovitz.
On polynomial equations in Banach space, perturbation techniques and applications
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Ioannis K. Argyros
1987-03-01
Full Text Available We use perturbation techniques to solve the polynomial equation in Banach space. Our techniques provide more accurate information on the location of solutions and yield existence and uniqueness in cases not covered before. An example is given to justify our method.
On the uniqueness of minimal projections in Banach spaces
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Ewa Szlachtowska
2012-01-01
Full Text Available Let \\(X\\ be a uniformly convex Banach space with a continuous semi-inner product. We investigate the relation of orthogonality in \\(X\\ and generalized projections acting on \\(X\\. We prove uniqueness of orthogonal and co-orthogonal projections.
The reconstruction property in Banach spaces and a perturbation theorem
DEFF Research Database (Denmark)
Casazza, P.G.; Christensen, Ole
2008-01-01
Perturbation theory is a fundamental tool in Banach space theory. However, the applications of the classical results are limited by the fact that they force the perturbed sequence to be equivalent to the given sequence. We will develop a more general perturbation theory that does not force equivalence of the sequences.
On nonlocal problems for fractional differential equations in Banach spaces
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XiWang Dong
2011-01-01
Full Text Available In this paper, we study the existence and uniqueness of solutions to the nonlocal problems for the fractional differential equation in Banach spaces. New sufficient conditions for the existence and uniqueness of solutions are established by means of fractional calculus and fixed point method under some suitable conditions. Two examples are given to illustrate the results.
Functional differential equations with infinite delay in Banach spaces
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Tijun Xiao
1991-09-01
Full Text Available In this paper, a definition of the fundamental operator for the linear autonomous functional differential equation with infinite delay in a Banach space is given, and some sufficient and necessary conditions of the fundamental operator being exponentially stable in abstract phase spaces which satisfy some suitable hypotheses are obtained. Moreover, we discuss the relation between the exponential asymptotic stability of the zero solution of nonlinear functional differential equation with infinite delay in a Banach space and the exponential stability of the solution semigroup of the corresponding linear equation, and find that the exponential stability problem of the zero solution for the nonlinear equation can be discussed only in the exponentially fading memory phase space.
Integral operators on the section space of a Banach bundle
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D. A. Robbins
1993-09-01
Full Text Available Let ÃÂ€:EÃ¢Â†Â’X and ÃÂ:FÃ¢Â†Â’X be bundles of Banach spaces, where X is a compact Hausdorff space, and let V be a Banach space. Let ÃŽÂ“(ÃÂ€ denote the space of sections of the bundle ÃÂ€. We obtain two representations of integral operators T:ÃŽÂ“(ÃÂ€Ã¢Â†Â’V in terms of measures. The first generalizes a recent result of P. Saab, the second generalizes a theorem of Grothendieck. We also study integral operators T:ÃŽÂ“(ÃÂ€Ã¢Â†Â’ÃŽÂ“(ÃÂ which are C(X-linear.
Integrals and Banach spaces for finite order distributions
Talvila, Erik
2011-01-01
Let $\\Bc$ denote the real-valued functions continuous on the extended real line and vanishing at $-\\infty$. Let $\\Br$ denote the functions that are left continuous, have a right limit at each point and vanish at $-\\infty$. Define $\\acn$ to be the space of tempered distributions that are the $n$th distributional derivative of a unique function in $\\Bc$. Similarly with $\\arn$ from $\\Br$. A type of integral is defined on distributions in $\\acn$ and $\\arn$. The multipliers are iterated integrals of functions of bounded variation. For each $n\\in\\N$, the spaces $\\acn$ and $\\arn$ are Banach spaces, Banach lattices and Banach algebras isometrically isomorphic to $\\Bc$ and $\\Br$, respectively. Under the ordering in this lattice, if a distribution is integrable then its absolute value is integrable. The dual space is isometrically isomorphic to the functions of bounded variation. The space $\\ac^1$ is the completion of the $L^1$ functions in the Alexiewicz norm. The space $\\ar^1$ contains all finite signed Borel measure...
Banach Contraction Principle for Cyclical Mappings on Partial Metric Spaces
Abdeljawad, Thabet; Mukheimer, Aiman; Zaidan, Younes
2011-01-01
In this paper, we prove that the Banach contraction principle proved by S. G. Matthews in 1994 on 0--complete partial metric spaces can be extended to cyclical mappings. However, the generalized contraction principle proved by D. Ili\\'{c}, V. Pavlovi\\'{c} and V. Rako\\u{c}evi\\'{c} in "Some new extensions of Banach's contraction principle to partial metric spaces, Appl. Math. Lett. 24 (2011), 1326--1330" on complete partial metric spaces can not be extended to cyclical mappings. Some examples are given to illustrate the effectiveness of our results. Moreover, we generalize some of the results obtained by W. A. Kirk, P. S. Srinivasan and P. Veeramani in "Fixed points for mappings satisfying cyclical contractive conditions, Fixed Point Theory 4 (1) (2003),79--89". Finally, an Edelstein's type theorem is also extended in case one of the sets in the cyclic decomposition is 0-compact.
Radon-Nikod\\'ym compact spaces of low weight and Banach spaces
Avile?s, Antonio
2010-01-01
We prove that a continuous image of a Radon-Nikod\\'ym compact space of weight less than b is Radon-Nikod\\'ym compact. As a Banach space counterpart, subspaces of Asplund generated Banach spaces of density character less than b are Asplund generated. In this case, in addition, there exists a subspace of an Asplund generated space which is not Asplund generated which has density character exactly b.
On best proximity points in metric and Banach spaces
Espinola, Rafa
2009-01-01
In this paper we study the existence and uniqueness of best proximity points of cyclic contractions as well as the convergence of iterates to such proximity points. We do it from two different approaches, leading each one of them to different results which complete, if not improve, other similar results in the theory. Results in this paper stand for Banach spaces, geodesic metric spaces and metric spaces. We also include an appendix on CAT(0) spaces where we study the particular behavior of these spaces regarding the problems we are concerned with.
Strong convergence of an iterative sequence for maximal monotone operators in a Banach space
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Wataru Takahashi
2004-04-01
Full Text Available We first introduce a modified proximal point algorithm for maximal monotone operators in a Banach space. Next, we obtain a strong convergence theorem for resolvents of maximal monotone operators in a Banach space which generalizes the previous result by Kamimura and Takahashi in a Hilbert space. Using this result, we deal with the convex minimization problem and the variational inequality problem in a Banach space.
Geometric properties of Banach spaces and nonlinear iterations
Chidume, Charles
2009-01-01
Nonlinear functional analysis and applications is an area of study that has provided fascination for many mathematicians across the world. This monograph delves specifically into the topic of the geometric properties of Banach spaces and nonlinear iterations, a subject of extensive research over the past thirty years. Chapters 1 to 5 develop materials on convexity and smoothness of Banach spaces, associated moduli and connections with duality maps. Key results obtained are summarized at the end of each chapter for easy reference. Chapters 6 to 23 deal with an in-depth, comprehensive and up-to-date coverage of the main ideas, concepts and results on iterative algorithms for the approximation of fixed points of nonlinear nonexpansive and pseudo-contractive-type mappings. This includes detailed workings on solutions of variational inequality problems, solutions of Hammerstein integral equations, and common fixed points (and common zeros) of families of nonlinear mappings. Carefully referenced and full of recent,...
Squared-Norm Empirical Process in Banach Space
Vu, Vincent Q.; Lei, Jing
2013-01-01
This note extends a recent result of Mendelson on the supremum of a quadratic process to squared norms of functions taking values in a Banach space. Our method of proof is a reduction by a symmetrization argument and observation about the subadditivity of the generic chaining functional. We provide an application to the supremum of a linear process in the sample covariance matrix indexed by finite rank, positive definite matrices.
Polynomial algebras and smooth functions in Banach spaces.
Czech Academy of Sciences Publication Activity Database
D'Alessandro, Stefania; Hájek, Petr Pavel
2014-01-01
Ro?. 266, ?. 3 (2014), s. 1627-1646. ISSN 0022-1236 R&D Projects: GA ?R(CZ) GAP201/11/0345; GA MŠk(CZ) 7AMB12FR003 Institutional support: RVO:67985840 Keywords : polynomials in Banach space Subject RIV: BA - General Mathematics Impact factor: 1.152, year: 2013 http://www.sciencedirect.com/science/article/pii/S0022123613004588
Some problems on ordinary differential equations in Banach spaces.
Czech Academy of Sciences Publication Activity Database
Hájek, Petr Pavel; Vivi, P.
2010-01-01
Ro?. 104, ?. 2 (2010), s. 245-255. ISSN 1578-7303 R&D Projects: GA AV ?R IAA100190801; GA ?R GA201/07/0394 Institutional research plan: CEZ:AV0Z10190503 Keywords : Banach space * ODE * Peano's theorem Subject RIV: BA - General Mathematics Impact factor: 0.400, year: 2010 http://link.springer.com/article/10.5052%2FRACSAM.2010.16
Geometry and Gâteaux smoothness in separable Banach spaces.
Czech Academy of Sciences Publication Activity Database
Hájek, Petr Pavel; Montesinos, V.; Zizler, Václav
2012-01-01
Ro?. 6, ?. 2 (2012), s. 201-232. ISSN 1846-3886 R&D Projects: GA ?R(CZ) GAP201/11/0345; GA AV ?R IAA100190901 Institutional research plan: CEZ:AV0Z10190503 Keywords : Gâteaux differentiable norms * extreme points * Radon -Nikodým property Subject RIV: BA - General Mathematics Impact factor: 0.529, year: 2012 http://oam.ele-math.com/06-15/Geometry-and-Gateaux-smoothness-in-separable-Banach-spaces
Almost automorphic solutions of some differential equations in Banach spaces
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Gaston Mandata N'Guerekata
2000-03-01
Full Text Available We discuss the conditions under which bounded solutions of the evolution equation xÃ¢Â€Â²(t=Ax(t+f(t in a Banach space are almost automorphic whenever f(t is almost automorphic and A generates a C0-group of strongly continuous operators. We also give a result for asymptotically almost automorphic solutions for the more general case of xÃ¢Â€Â²(t=Ax(t+f(t,x(t.
A proximal point method for nonsmooth convex optimization problems in Banach spaces
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Y. I. Alber
1997-01-01
Full Text Available In this paper we show the weak convergence and stability of the proximal point method when applied to the constrained convex optimization problem in uniformly convex and uniformly smooth Banach spaces. In addition, we establish a nonasymptotic estimate of convergence rate of the sequence of functional values for the unconstrained case. This estimate depends on a geometric characteristic of the dual Banach space, namely its modulus of convexity. We apply a new technique which includes Banach space geometry, estimates of duality mappings, nonstandard Lyapunov functionals and generalized projection operators in Banach spaces.
Convergence theorems for Banach space valued integrable multifunctions
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Nikolaos S. Papageorgiou
1987-09-01
Full Text Available In this work we generalize a result of Kato on the pointwise behavior of a weakly convergent sequence in the Lebesgue-Bochner spaces LXP(ÃŽÂ©Ã¢Â€Â‰(1Ã¢Â‰Â¤pÃ¢Â‰Â¤Ã¢ÂˆÂž. Then we use that result to prove Fatou's type lemmata and dominated convergence theorems for the Aumann integral of Banach space valued measurable multifunctions. Analogous convergence results are also proved for the sets of integrable selectors of those multifunctions. In the process of proving those convergence theorems we make some useful observations concerning the Kuratowski-Mosco convergence of sets.
Linearization of class C1 for contractions on Banach spaces
Rodrigues, Hildebrando M.; Solà-Morales, J.
In this work we prove a C1-linearization result for contraction diffeomorphisms, near a fixed point, valid in infinite-dimensional Banach spaces. As an intermediate step, we prove a specific result of existence of invariant manifolds, which can be interesting by itself and that was needed on the proof of our main theorem. Our results essentially generalize some classical results by P. Hartman in finite dimensions, and a result of Mora-Sola-Morales in the infinite-dimensional case. It is shown that the result can be applied to some abstract systems of semilinear damped wave equations.
Square variation of Brownian paths in Banach spaces
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Mou-Hsiung Chang
1982-09-01
Full Text Available It is known that if {W(t,Ã¢Â€Â‰Ã¢Â€Â‰Ã¢Â€Â‰0Ã¢Â‰Â¤tÃ¢Â‰Â¤1} is a standard Brownian motion in Ã¢Â„Â then limnÃ¢Â†Â’Ã¢ÂˆÂžÃ¢ÂˆÂ‘i=12n|W(i/2nÃ¢ÂˆÂ’W((iÃ¢ÂˆÂ’1/2n|2=1 almost surely. We generalize this celebrated theorem of Levy to Brownian motion in real separable Banach spaces.
p-adic Banach space operators and adelic Banach space operators
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Ilwoo Cho
2014-01-01
Full Text Available In this paper, we study non-Archimedean Banach \\(*\\-algebras \\(\\frak{M}_{p}\\ over the \\(p\\-adic number fields \\(\\mathbb{Q}_{p}\\, and \\(\\frak{M}_{\\mathbb{Q}}\\ over the adele ring \\(\\mathbb{A}_{\\mathbb{Q}}\\. We call elements of \\(\\frak{M}_{p}\\, \\(p\\-adic operators, for all primes \\(p\\, respectively, call those of \\(\\frak{M}_{\\mathbb{Q}}\\, adelic operators. We characterize \\(\\frak{M}_{ \\mathbb{Q}}\\ in terms of \\(\\frak{M}_{p}\\'s. Based on such a structure theorem of \\(\\frak{M}_{\\mathbb{Q}}\\, we introduce some interesting \\(p\\-adic operators and adelic operators.
Smoothness in Banach spaces. Selected problems.
Czech Academy of Sciences Publication Activity Database
Fabian, Marián; Montesinos, V.; Zizler, Václav
2006-01-01
Ro?. 100, ?. 2 (2006), s. 101-125. ISSN 1578-7303 R&D Projects: GA ?R(CZ) GA201/04/0090; GA AV ?R(CZ) IAA100190610 Institutional research plan: CEZ:AV0Z10190503 Keywords : smooth norm * renorming * weakly compactly generated space Subject RIV: BA - General Mathematics
On strictly singular operators between separable Banach spaces
Beanland, Kevin
2010-01-01
Let $X$ and $Y$ be separable Banach spaces and denote by $\\sss\\sss(X,Y)$ the subset of $\\llll(X,Y)$ consisting of all strictly singular operators. We study various ordinal ranks on the set $\\sss\\sss(X,Y)$. Our main results are summarized as follows. Firstly, we define a new rank $\\rs$ on $\\sss\\sss(X,Y)$. We show that $\\rs$ is a co-analytic rank and that dominates the rank $\\varrho$ introduced by Androulakis, Dodos, Sirotkin and Troitsky [Israel J. Math., 169 (2009), 221-250]. Secondly, for every $1\\leq p<+\\infty$ we construct a Banach space $Y_p$ with an unconditional basis such that $\\sss\\sss(\\ell_p, Y_p)$ is a co-analytic non-Borel subset of $\\llll(\\ell_p,Y_p)$ yet every strictly singular operator $T:\\ell_p\\to Y_p$ satisfies $\\varrho(T)\\leq 2$. This answers a question of Argyros.
Weighted Admissibility and Wellposedness of linear systems in Banach spaces
Haak, B H; Haak, Bernhard H.; Kunstmann, Peer Christian
2006-01-01
We study linear control systems in infinite--dimensional Banach spaces governed by analytic semigroups. For $p\\in[1,\\infty]$ and $\\alpha\\in\\RR$ we introduce the notion of $L^p$--admissibility of type $\\alpha$ for unbounded observation and control operators. Generalising earlier work by Le Merdy and the first named author and Le Merdy we give conditions under which $L^p$--admissibility of type $\\alpha$ is characterised by boundedness conditions which are similar to those in the well--known Weiss conjecture. We also study $L^p$--wellposedness of type $\\alpha$ for the full system. Here we use recent ideas due to Pruess and Simonett. Our results are illustrated by a controlled heat equation with boundary control and boundary observation where we take Lebesgue and Besov spaces as state space. This extends the considerations from Byrnes, Gilliam, Shubov and Weiss to non--Hilbertian settings and to $p\
Frechet Differentiability of Lipschitz Functions and Porous Sets in Banach Spaces
Lindenstrauss, Joram; Tiaer, Jaroslav
2012-01-01
This book makes a significant inroad into the unexpectedly difficult question of existence of Fréchet derivatives of Lipschitz maps of Banach spaces into higher dimensional spaces. Because the question turns out to be closely related to porous sets in Banach spaces, it provides a bridge between descriptive set theory and the classical topic of existence of derivatives of vector-valued Lipschitz functions. The topic is relevant to classical analysis and descriptive set theory on Banach spaces. The book opens several new research directions in this area of geometric nonlinear functional analysi
Stochastic integration in Banach spaces theory and applications
Mandrekar, Vidyadhar
2015-01-01
Considering Poisson random measures as the driving sources for stochastic (partial) differential equations allows us to incorporate jumps and to model sudden, unexpected phenomena. By using such equations the present book introduces a new method for modeling the states of complex systems perturbed by random sources over time, such as interest rates in financial markets or temperature distributions in a specific region. It studies properties of the solutions of the stochastic equations, observing the long-term behavior and the sensitivity of the solutions to changes in the initial data. The authors consider an integration theory of measurable and adapted processes in appropriate Banach spaces as well as the non-Gaussian case, whereas most of the literature only focuses on predictable settings in Hilbert spaces. The book is intended for graduate students and researchers in stochastic (partial) differential equations, mathematical finance and non-linear filtering and assumes a knowledge of the required integrati...
A note on local asymptotic behaviour for Brownian motion in Banach spaces
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Mou-Hsiung Chang
1979-12-01
Full Text Available In this paper we obtain an integral characterization of a two-sided upper function for Brownian motion in a real separable Banach space. This characterization generalizes that of Jain and Taylor [2] where B=Ã¢Â„Ân. The integral test obtained involves the index of a mean zero Gaussian measure on the Banach space, which is due to Kuelbs [3]. The special case that when B is itself a real separable Hilbert space is also illustrated.
Convergence Theorems for Asymptotically Nonexpansive Mappings in Banach Spaces
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Meijuan Shang
2008-03-01
Full Text Available Let E be a uniformly convex Banach space, and let K be a nonempty convex closed subset which is also a nonexpansive retract of E. Let T: K ® E be an asymptotically nonexpansive mapping with {kn} Ì [1, ¥ such that (å from n=1 to ¥(kn - 1 ¥ and let F(T be nonempty, where F(T denotes the fixed points set of T. Let{an}, {bn},{gn}, {a¢n}, {b¢n}, {g¢n}, {a¢¢n}, {b¢¢n}and {g¢¢n}be real sequences in [0, 1] such that an +bn +gn =a¢n +b¢n +g¢n =a¢¢n +b¢¢n +g¢¢n = 1 and e £ an,a¢n, a¢¢n £ 1 - e for all n Î N and some e > 0, starting with arbitrary x1 Î K,define the sequence { xn} by setting zn = P(a¢¢nT(PTn-1xn+ b¢¢nxn+ g¢¢nwn, yn =P(a¢nT(PTn-1zn+ b¢nxn+ g¢nvn, xn+1 =P(anT(PTn-1yn+ bnxn+ gnun,with the restrictions (å from n=1 to ¥ (gn ¥,(å from n=1 to ¥ (g¢n ¥ and (å from n=1 to ¥ (g¢¢n ¥ where { wn} , { vn} and { un} are bounded sequences in K. (i If E is realuniformly convex Banach space satisfying Opial's condition, then weak convergence of { xn} to some p Î F(T is obtained; (ii If T satisfies condition (A, then { xn} convergence strongly to some p Î F(T.
Strong convergence theorems for uniformly L-Lipschitzian mappings in Banach spaces
International Nuclear Information System (INIS)
Let E be a real reflexive Banach space with uniform Gateaux differentiable norm, K be a nonempty bounded closed and convex subset of E , T : K ? K be a uniformly L-Lipschitzian mapping such that F (T) := {x element of K : Tx = x} ? 0, u element of K be fixed and let {?n}n?0 and {?n}n?0 subset of (0, 1) be such that limn?? ?n = 0 = limn? ? ?n and limn? ?(?n - 1)/ ?n = 0, where ?n ?j=0n ?j and ?j = 1 + ?j?jL. Let Sn := (1 - ?n?n)I + ?n?nTn. It is proved that there exists some integer N0 > 1, such that for each n ? N0, there exists unique xn element of K such that xn = ?nu+(1 -?n) 1/ (n + 1) ?j=0n Sjxn. If ? : E ? R is defined by ? (y) := LIMn vertical bar vertical bar xn -y vertical bar vertical bar2 for all y element of E here LIM denotes a Banach limit, vertical bar vertical bar xn - Txn vertical bar vertical bar ? 0 as n ? ? and Kmin intersection F (T) ? 0, where Kmin := {x element of E : ? (x) = min (u element of K) ? (u) }, then it is proved that {xn} converges strongly to a fixed point of T. As an application, it is proved that the iterative process, z0 element of K, zn+1 alpha#nu + (1 - ?n) 1/ (n + 1) ?j=0n Sjzn , n ? 0, under suitable conditions on the iteration parameters, converges strongly to a fixed point of T. (author)
Greedy Algorithms for Reduced Bases in Banach Spaces
DeVore, Ronald; Wojtaszczyk, Przemyslaw
2012-01-01
Given a Banach space X and one of its compact sets F, we consider the problem of finding a good n dimensional space X_n \\subset X which can be used to approximate the elements of F. The best possible error we can achieve for such an approximation is given by the Kolmogorov width d_n(F)_X. However, finding the space which gives this performance is typically numerically intractable. Recently, a new greedy strategy for obtaining good spaces was given in the context of the reduced basis method for solving a parametric family of PDEs. The performance of this greedy algorithm was initially analyzed in A. Buffa, Y. Maday, A.T. Patera, C. Prud'homme, and G. Turinici, "A Priori convergence of the greedy algorithm for the parameterized reduced basis", M2AN Math. Model. Numer. Anal., 46(2012), 595-603 in the case X = H is a Hilbert space. The results there were significantly improved on in P. Binev, A. Cohen, W. Dahmen, R. DeVore, G. Petrova, and P. Wojtaszczyk, "Convergence rates for greedy algorithms in reduced bases ...
Initial value problems for integro-differential equations of Volterra type in Banach spaces
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Dajun Guo
1994-01-01
Full Text Available This paper investigates the extremal solutions of initial value problems for first order integro-differential equations of Volterra type in Banach spaces by means of establishing a comparison result.
Strong convergence theorems for infinite families of nonexpansive mappings in general Banach spaces
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Suzuki Tomonari
2005-01-01
Full Text Available In 1979, Ishikawa proved a strong convergence theorem for finite families of nonexpansive mappings in general Banach spaces. Motivated by Ishikawa's result, we prove strong convergence theorems for infinite families of nonexpansive mappings.
Strong convergence theorems for infinite families of nonexpansive mappings in general Banach spaces
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Tomonari Suzuki
2005-04-01
Full Text Available In 1979, Ishikawa proved a strong convergence theorem for finite families of nonexpansive mappings in general Banach spaces. Motivated by Ishikawa's result, we prove strong convergence theorems for infinite families of nonexpansive mappings.
Existence of solutions for semilinear nonlocal Cauchy problems in Banach spaces
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Xingmei Xue
2005-06-01
Full Text Available In this paper, we study a semilinear differential equations with nonlocal initial conditions in Banach spaces. We derive conditions for $f$, $T(t$, and $g$ for the existence of mild solutions.
Nonsmooth and nonlocal differential equations in lattice-ordered Banach spaces
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S. Heikkilä
2005-06-01
Full Text Available We derive existence results for initial and boundary value problems in lattice-ordered Banach spaces. The considered problems can be singular, functional, discontinuous, and nonlocal. Concrete examples are also solved.
Nonsmooth and nonlocal differential equations in lattice-ordered Banach spaces
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Heikkilä S
2005-01-01
Full Text Available We derive existence results for initial and boundary value problems in lattice-ordered Banach spaces. The considered problems can be singular, functional, discontinuous, and nonlocal. Concrete examples are also solved.
Ma, Haifeng
2012-01-01
In this dissertation, continuous homogeneous selections for the set-valued metric generalized inverses T? of linear operators T in Banach spaces are investigated by means of the methods of geometry of Banach spaces. Necessary and sufficient conditions in order that the set valued metric generalized inverses T? of bounded linear operators T have continuous homogeneous selections are given. The results give an answer to the problem posed by Nashed and Votruba. Secondly, the perturbations of...
Convergence on Composite Iterative Schemes for Nonexpansive Mappings in Banach Spaces
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Jong Soo Jung
2008-05-01
Full Text Available Let E be a reflexive Banach space with a uniformly GÃƒÂ¢teaux differentiable norm. Suppose that every weakly compact convex subset of E has the fixed point property for nonexpansive mappings. Let C be a nonempty closed convex subset of E, f:CÃ¢Â€Â‰Ã¢Â€Â‰Ã¢Â†Â’Ã¢Â€Â‰Ã¢Â€Â‰C a contractive mapping (or a weakly contractive mapping, and T:CÃ¢Â€Â‰Ã¢Â€Â‰Ã¢Â†Â’Ã¢Â€Â‰Ã¢Â€Â‰C nonexpansive mapping with the fixed point set F(TÃ¢Â€Â‰Ã¢Â€Â‰Ã¢Â‰Â Ã¢Â€Â‰Ã¢Â€Â‰Ã¢ÂˆÂ…. Let {xn} be generated by a new composite iterative scheme: yn=ÃŽÂ»nf(xn+(1Ã¢ÂˆÂ’ÃŽÂ»nTxn, xn+1=(1Ã¢ÂˆÂ’ÃŽÂ²nyn+ÃŽÂ²nTyn, (nÃ¢Â‰Â¥0. It is proved that {xn} converges strongly to a point in F(T, which is a solution of certain variational inequality provided that the sequence {ÃŽÂ»n}Ã¢ÂŠÂ‚(0,1 satisfies limnÃ¢Â†Â’Ã¢ÂˆÂžÃŽÂ»n=0 and Ã¢ÂˆÂ‘n=1Ã¢ÂˆÂžÃŽÂ»n=Ã¢ÂˆÂž, {ÃŽÂ²n}Ã¢ÂŠÂ‚[0,a for some 0
Regularity of solutions of Sobolev type semilinear integrodifferential equations in Banach spaces
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Krishnan Balachandran
2003-11-01
Full Text Available In this article, we prove the existence of mild and classical solutions of Sobolev type semilinear integrodifferential equations of the form $$ frac{d}{dt}[Ex(t] = A[x(t+int_0^tF(t-sx(sds]+f(t,x(t $$ in Banach spaces. The results are obtained by using the Banach contraction mapping principle and resolvent operator. An application is provided to illustrate the theory.
Banach algebras generated by an invertible isometry of an $L^p$-space
Gardella, Eusebio; Thiel, Hannes
2014-01-01
We study and classify Banach algebras that are generated by an invertible isometry of an $L^p$-space together with its inverse. We associate to each such isometry a spectral invariant which contains considerably more information than its spectrum as an operator. We show that this invariant describes the isometric isomorphism type of the Banach algebra that the isometry generates together with its inverse. In the case of invertible isometries with full spectrum, these Banac...
Scientific Electronic Library Online (English)
Violeta, Petkova.
2012-10-01
Full Text Available SciELO Chile | Language: English Abstract in spanish Estudiamos el espectro de los multiplicadores (operadores acotados que conmutan con el operador shift ) en un espacio de Banach [...] =24 id="_x0000_i1042" src="http://fbpe/img/cubo/v14n3/art02-03.jpg" alt="http://fbpe/img/cubo/v14n3/art02-03.jpg">de sucesiones en . Dado un multiplicador , probamos que donde es el símbolo de . Obtenemos un resultados similar para el espectro de un operador que conmuta con el shift en un espacio de Banach de sucesiones en . Generalizamos los resultados sobre multiplicadores en espacios de Banach de sucesiones en . Abstract in english We study the spectrum of multipliers (bounded operators commuting with the shift operator ) on a Banach space [...] 51" src="http://fbpe/img/cubo/v14n3/art02-03.jpg" alt="http://fbpe/img/cubo/v14n3/art02-03.jpg">of sequences on . Given a multiplier , we prove that where is the symbol of . We obtain a similar result for the spectrum of an operator commuting with the shift on a Banach space of sequences on . We generalize the results for multipliers on Banach spaces of sequences on .
Space charge equation calculations for the reflex triode
International Nuclear Information System (INIS)
The Poisson equation solution of the space charge problem for the reflex triode is reviewed and illustrated with a number of examples. The numerical calculation technique for obtaining these results is briefly described. The results show that the characteristics of the triode are strong functions of the reflex-electron kinetic-energy spectrum, especially of the high-energy electrons
Metric and Generalized Projection Operators in Banach Spaces Properties and Applications
Alber, Y I
1993-01-01
Metric projection operators can be defined in similar wayin Hilbert and Banach spaces. At the same time, they differ signifitiantly in their properties. Metric projection operator in Hilbert space is a monotone and nonexpansive operator. It provides an absolutely best approximation for arbitrary elements from Hilbert space by the elements of convex closed sets . This leads to a variety of applications of this operator for investigating theoretical questions in analysis and for approximation methods. Metric projection operators in Banach space do not have properties mentioned above and their applications are not straightforward. Two of the most important applications of the method of metric projection operators are as follows: 1. Solve a variational inequality by the iterative-projection method, 2. Find common point of convex sets by the iterative-projection method. In Banach space these problems can not be solved in the framework of metric projection operators. Therefore, in the present paper we introduce new...
Algorithm for Solving a Generalized Mixed Equilibrium Problem with Perturbation in a Banach Space
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Jen-Chih Yao
2010-01-01
Full Text Available Let B be a real Banach space with the dual space B*. Let ?:B?R?{+?} be a proper functional and let ?:B×B?R be a bifunction. In this paper, a new concept of ?-proximal mapping of ? with respect to ? is introduced. The existence and Lipschitz continuity of the ?-proximal mapping of ? with respect to ? are proved. By using properties of the ?-proximal mapping of ? with respect to ?, a generalized mixed equilibrium problem with perturbation (for short, GMEPP is introduced and studied in Banach space B. An existence theorem of solutions of the GMEPP is established and a new iterative algorithm for computing approximate solutions of the GMEPP is suggested. The strong convergence criteria of the iterative sequence generated by the new algorithm are established in a uniformly smooth Banach space B, and the weak convergence criteria of the iterative sequence generated by this new algorithm are also derived in B=H a Hilbert space.
Accretive operators and Banach Alaoglu theorem in Linear 2-normed spaces
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P. K Harikrishnan
2011-12-01
Full Text Available In this paper we introduce the concept of accretive operator in linear 2-normed spaces, focusing on the relationships and the various aspects of accretive, m-accretive and maximal accretive operators. We prove the analogous of Banach-Alaoglu theorem in linear 2- normed spaces, obtaining an equivalent definition for accretive operators in linear 2-normed spaces.
Accretive operators and Banach Alaoglu theorem in Linear 2-normed spaces
Scientific Electronic Library Online (English)
P. K, Harikrishnan; Bernardo La Fuerza, Guillén; K. T, Ravindran.
2011-12-01
Full Text Available In this paper we introduce the concept of accretive operator in linear 2-normed spaces, focusing on the relationships and the various aspects of accretive, m-accretive and maximal accretive operators. We prove the analogous of Banach-Alaoglu theorem in linear 2- normed spaces, obtaining an equivalen [...] t definition for accretive operators in linear 2-normed spaces.
Haak, B; Haak, Bernhard; Neerven, Jan van
2006-01-01
Here, $A$ is the generator of a strongly continuous semigroup of operators on a Banach space $E$, $B$ is a bounded linear operator from a separable Hilbert space $H$ into $E$, and $W_H$ is an $H$--cylindrical Brownian motion.
International Nuclear Information System (INIS)
The method of approximate inverse is a mollification method for stably solving inverse problems. In its original form it has been developed to solve operator equations in L2-spaces and general Hilbert spaces. We show that the method of approximate inverse can be extended to solve linear, ill-posed problems in Banach spaces. This paper is restricted to function spaces. The method itself consists of evaluations of dual pairings of the given data with reconstruction kernels that are associated with mollifiers and the dual of the operator. We first define what we mean by a mollifier in general Banach spaces and then investigate two settings more exactly: the case of Lp-spaces and the case of the Banach space of continuous functions on a compact set. For both settings we present the criteria turning the method of approximate inverse into a regularization method and prove convergence with rates. As an application we refer to x-ray diffractometry which is a technique of non-destructive testing that is concerned with computing the stress tensor of a specimen. Since one knows that the stress tensor is smooth, x-ray diffractometry can appropriately be modelled by a Banach space setting using continuous functions
Periodic and almost periodic solutions for multi-valued differential equations in Banach spaces
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E. Hanebaly
2000-03-01
Full Text Available It is known that for $omega$-periodic differential equations of monotonous type, in uniformly convex Banach spaces, the existence of a bounded solution on ${Bbb R}^+$ is equivalent to the existence of an omega-periodic solution (see Haraux [5] and Hanebaly [7, 10]. It is also known that if the Banach space is strictly convex and the equation is almost periodic and of monotonous type, then the existence of a continuous solution with a precompact range is equivalent to the existence of an almost periodic solution (see Hanebaly [8]. In this note we want to generalize the results above for multi-valued differential equations.
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Chen Jia-wei
2011-01-01
Full Text Available Abstract In order to unify some variational inequality problems, in this paper, a new system of generalized quasivariational inclusion (for short, (SGQVI is introduced. By using Banach contraction principle, some existence and uniqueness theorems of solutions for (SGQVI are obtained in real Banach spaces. Two new iterative algorithms to find the common element of the solutions set for (SGQVI and the fixed points set for Lipschitz mappings are proposed. Convergence theorems of these iterative algorithms are established under suitable conditions. Further, convergence rates of the convergence sequences are also proved in real Banach spaces. The main results in this paper extend and improve the corresponding results in the current literature. 2000 MSC: 47H04; 49J40.
Ã¢Â„Â‚-convexity in infinite-dimensional Banach spaces and applications to Kergin interpolation
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Lars Filipsson
2006-07-01
Full Text Available We investigate the concepts of linear convexity and Ã¢Â„Â‚-convexity in complex Banach spaces. The main result is that any Ã¢Â„Â‚-convex domain is necessarily linearly convex. This is a complex version of the Hahn-Banach theorem, since it means the following: given a Ã¢Â„Â‚-convex domain ÃŽÂ© in the Banach space X and a point pÃ¢ÂˆÂ‰ÃŽÂ©, there is a complex hyperplane through p that does not intersect ÃŽÂ©. We also prove that linearly convex domains are holomorphically convex, and that Kergin interpolation can be performed on holomorphic mappings defined in Ã¢Â„Â‚-convex domains.
Schuster, Thomas; Hofmann, Bernd; Kaltenbacher, Barbara
2012-10-01
Inverse problems can usually be modelled as operator equations in infinite-dimensional spaces with a forward operator acting between Hilbert or Banach spaces—a formulation which quite often also serves as the basis for defining and analyzing solution methods. The additional amount of structure and geometric interpretability provided by the concept of an inner product has rendered these methods amenable to a convergence analysis, a fact which has led to a rigorous and comprehensive study of regularization methods in Hilbert spaces over the last three decades. However, for numerous problems such as x-ray diffractometry, certain inverse scattering problems and a number of parameter identification problems in PDEs, the reasons for using a Hilbert space setting seem to be based on conventions rather than an appropriate and realistic model choice, so often a Banach space setting would be closer to reality. Furthermore, non-Hilbertian regularization and data fidelity terms incorporating a priori information on solution and noise, such as general Lp-norms, TV-type norms, or the Kullback-Leibler divergence, have recently become very popular. These facts have motivated intensive investigations on regularization methods in Banach spaces, a topic which has emerged as a highly active research field within the area of inverse problems. Meanwhile some of the most well-known regularization approaches, such as Tikhonov-type methods requiring the solution of extremal problems, and iterative ones like the Landweber method, the Gauss-Newton method, as well as the approximate inverse method, have been investigated for linear and nonlinear operator equations in Banach spaces. Convergence with rates has been proven and conditions on the solution smoothness and on the structure of nonlinearity have been formulated. Still, beyond the existing results a large number of challenging open questions have arisen, due to the more involved handling of general Banach spaces and the larger variety of concrete instances with special properties. The aim of this special section is to provide a forum for highly topical ongoing work in the area of regularization in Banach spaces, its numerics and its applications. Indeed, we have been lucky enough to obtain a number of excellent papers both from colleagues who have previously been contributing to this topic and from researchers entering the field due to its relevance in practical inverse problems. We would like to thank all contributers for enabling us to present a high quality collection of papers on topics ranging from various aspects of regularization via efficient numerical solution to applications in PDE models. We give a brief overview of the contributions included in this issue (here ordered alphabetically by first author). In their paper, Iterative regularization with general penalty term—theory and application to L1 and TV regularization, Radu Bot and Torsten Hein provide an extension of the Landweber iteration for linear operator equations in Banach space to general operators in place of the inverse duality mapping, which corresponds to the use of general regularization functionals in variational regularization. The L? topology in data space corresponds to the frequently occuring situation of uniformly distributed data noise. A numerically efficient solution of the resulting Tikhonov regularization problem via a Moreau-Yosida appriximation and a semismooth Newton method, along with a ?-free regularization parameter choice rule, is the topic of the paper L? fitting for inverse problems with uniform noise by Christian Clason. Extension of convergence rates results from classical source conditions to their generalization via variational inequalities with a priori and a posteriori stopping rules is the main contribution of the paper Regularization of linear ill-posed problems by the augmented Lagrangian method and variational inequalities by Klaus Frick and Markus Grasmair, again in the context of some iterative method. A powerful tool for proving convergence rates of Tikhonov type but also othe
Khinchin inequality and Banach-Saks type properties in rearrangement-invariant spaces
Sukochev, F
2010-01-01
{\\it We study the class of all rearrangement-invariant (=r.i.) function spaces $E$ on $[0,1]$ such that there exists $00$ does not depend on $n$. We completely characterize all Lorentz spaces having this property and complement classical results of Rodin and Semenov for Orlicz spaces $exp(L_p)$, $p\\ge 1$. We further apply our results to the study of Banach-Saks index sets in r.i. spaces.
Generalized Bohl-Perron principle for differential equations with delay in a Banach spaces
Michael Gil'
2013-01-01
We consider a linear homogeneous functional differential equation with delay in a Banach space. It is proved that if the corresponding non-homogeneous equation, with an arbitrary free term bounded on the positive half-line and with the zero initial condition, has a bounded solution, then the considered homogeneous equation is exponentially stable.
Psi-exponential dichotomy for linear differential equations in a Banach space
Atanaska Georgieva; Hristo Kiskinov; Stepan Kostadinov; Andrey Zahariev
2013-01-01
In this article we extend the concept psi-exponential and psi-ordinary dichotomies for homogeneous linear differential equations in a Banach space. With these two concepts we prove the existence of psi-bounded solutions of the appropriate inhomogeneous equation. A roughness of the psi-dichotomy is also considered.
Psi-exponential dichotomy for linear differential equations in a Banach space
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Atanaska Georgieva
2013-07-01
Full Text Available In this article we extend the concept psi-exponential and psi-ordinary dichotomies for homogeneous linear differential equations in a Banach space. With these two concepts we prove the existence of psi-bounded solutions of the appropriate inhomogeneous equation. A roughness of the psi-dichotomy is also considered.
Generalized Bohl-Perron principle for differential equations with delay in a Banach spaces
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Michael Gil'
2013-06-01
Full Text Available We consider a linear homogeneous functional differential equation with delay in a Banach space. It is proved that if the corresponding non-homogeneous equation, with an arbitrary free term bounded on the positive half-line and with the zero initial condition, has a bounded solution, then the considered homogeneous equation is exponentially stable.
Bound and periodic solutions of the Riccati equation in Banach space
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A. Ya. Dorogovtsev
1995-01-01
Full Text Available An abstract, nonlinear, differential equation in Banach space is considered. Conditions are presented for the existence of bounded solutions of this equation with a bounded right side, and also for the existence of stationary (periodic solutions of this equation with a stationary (periodic process in the right side.
Fixed point iterations for quasi-contractive maps in uniformly smooth Banach spaces
International Nuclear Information System (INIS)
Two well-known fixed point iteration methods are applied to approximate fixed points of quasi-contractive maps in real uniformly smooth Banach spaces. While our theorems generalize important known results, our method is of independent interest. (author). 25 refs
Terminal value problems of impulsive integro-differential equations in Banach spaces
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Dajun Guo
1997-01-01
Full Text Available This paper uses cone theory and the monotone iterative technique to investigate the existence of minimal nonnegative solutions of terminal value problems for first order nonlinear impulsive integro-differential equations of mixed type in a Banach space.
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K. Balachandran
2006-09-01
Full Text Available In this paper we prove the existence of mild and strong solutions of nonlinear time varying delay integrodifferential equations of Sobolev type with nonlocal conditions in Banach spaces. The results are obtained by using the theory of compact semigroups and Schaefer's fixed point theorem.
ON THE ALGEBRAIC DIMENSION OF BANACH SPACES OVER NON-ARCHIMEDEAN VALUED FIELDS OR ARBITRARY RANK
Scientific Electronic Library Online (English)
HERMINIA, OCHSENIUS; W. H., SCHIKHOF.
2007-12-01
Full Text Available SciELO Chile | Language: English Abstract in english Let K be a complete non-archimedean valued field of any rank, and let E be a K-Banach space with a countable topological base. We determine the algebraic dimension of E (2.3, 2.4, 3.1). [...
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An existence theorem for a new class of multi-valued variational inclusion problems is established in smooth Banach spaces. Further, it is shown that a sequence of a Mann-type iteration algorithm is strongly convergent to the solutions in this class of variational inclusion problems. (author)
Observational Banach Manifolds
Mehrpoya, Mohammad; Molaei, Mohammadreza
2014-01-01
In this paper, the concept of selective real manifolds is extended. It is proved that the product of two selective Banach manifolds is a selective Banach manifold. The notion of the $\\alpha$--level differentiation of the mappings between selective Banach manifolds is presented. Basic properties of $(r, \\alpha)$--differentiable maps are studied. Tangent space for at a point of a selective Banach manifold is considered.
Functional analysis an introduction to metric spaces, Hilbert spaces, and Banach algebras
Muscat, Joseph
2014-01-01
This textbook is an introduction to functional analysis suited to final year undergraduates or beginning graduates. Its various applications of Hilbert spaces, including least squares approximation, inverse problems, and Tikhonov regularization, should appeal not only to mathematicians interested in applications, but also to researchers in related fields. Functional Analysis adopts a self-contained approach to Banach spaces and operator theory that covers the main topics, based upon the classical sequence and function spaces and their operators. It assumes only a minimum of knowledge in elementary linear algebra and real analysis; the latter is redone in the light of metric spaces. It contains more than a thousand worked examples and exercises, which make up the main body of the book.
Jeu, Marcel; Tomiyama, Jun
2014-01-01
If $X$ is a compact Hausdorff space and $\\sigma$ is a homeomorphism of $X$, then a Banach algebra $\\ell^1(\\Sigma)$ of crossed product type is naturally associated with this topological dynamical system $\\Sigma=(X,\\sigma)$. If $X$ consists of one point, then $\\ell^1(\\Sigma)$ is the group algebra of the integers. We study the algebraically irreducible representations of $\\ell^1(\\Sigma)$ on complex vector spaces, its primitive ideals and its structure space. The finite dim...
International Nuclear Information System (INIS)
In this paper we deal with convergence rates for regularizing ill-posed problems with operator mapping from a Hilbert space into a Banach space. Since we cannot transfer the well-established convergence rates theory in Hilbert spaces, only few convergence rates results are known in the literature for this situation. Therefore we present an alternative approach for deriving convergence rates. Hereby we deal with so-called distance functions which quantify the violation of a reference source condition. With the aid of these functions we present error bounds and convergence rates for regularized solutions of linear and nonlinear problems when the reference source condition is not satisfied. We show that the approach of applying distance functions carries over the idea of considering generalized source conditions in Hilbert spaces to inverse problems in Banach spaces in a natural way. Introducing this topic for linear ill-posed problems we additionally show that this theory can be easily extended to nonlinear problems
From Hahn-Banach to monotonicity
Simons, Stephen
2008-01-01
In this new edition of LNM 1693 the essential idea is to reduce questions on monotone multifunctions to questions on convex functions. However, rather than using a “big convexification” of the graph of the multifunction and the “minimax technique”for proving the existence of linear functionals satisfying certain conditions, the Fitzpatrick function is used. The journey begins with a generalization of the Hahn-Banach theorem uniting classical functional analysis, minimax theory, Lagrange multiplier theory and convex analysis and culminates in a survey of current results on monotone multifunctions on a Banach space. The first two chapters are aimed at students interested in the development of the basic theorems of functional analysis, which leads painlessly to the theory of minimax theorems, convex Lagrange multiplier theory and convex analysis. The remaining five chapters are useful for those who wish to learn about the current research on monotone multifunctions on (possibly non reflexive) Banach spac...
Buried object detection by means of a Lp Banach-space inversion procedure
Estatico, Claudio; Fedeli, Alessandro; Pastorino, Matteo; Randazzo, Andrea
2015-01-01
Electromagnetic inspection techniques are becoming powerful tools for buried object detection and subsurface prospection in several applicative fields, such as civil engineering and archeology. However, the nonlinearity and ill-posedness of the underlying inverse problem make the development of efficient imaging techniques a very challenging task. In the present paper, an algorithm based on a regularizing approach in Lp Banach spaces is proposed for tackling such problems. The effectiveness of the approach is verified by means of numerical simulations in a noisy environment aimed at evaluating the reconstruction capabilities with respect to the choice of several model parameters. The reported results show that, for small targets, the use of Lp Banach spaces with 1 < p < 2 allows to obtain a better localization of different buried scatterers.
C0-semigroups of linear operators on some ultrametric Banach spaces
Toka Diagana
2006-01-01
C0-semigroups of linear operators play a crucial role in the solvability of evolution equations in the classical context. This paper is concerned with a brief conceptualization of C0-semigroups on (ultrametric) free Banach spaces E. In contrast with the classical setting, the parameter of a given C0-semigroup belongs to a clopen ball ÃŽÂ©r of the ground field K. As an illustration, we will discuss the solvability of some homogeneous p-adic differential equations.
Two-points problem for an evolutional first order equation in Banach space
????????, ?. ?.; ???????, ?. ?.
2010-01-01
Two-points nonlocal problem for the first order differential evolution equation with an operator coefficient in a Banach space $X$ is considered. An exponentially convergent algorithm is proposed and justified in assumption that the operator coefficient is strongly positive and some existence and uniqueness conditions are fulfilled. This algorithm leads to a system of linear equations that can be solved by fixed-point iteration. The algorithm provides exponentially convergen...
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Suzuki Tomonari
2006-01-01
Full Text Available We prove Browder's type strong convergence theorems for infinite families of nonexpansive mappings. One of our main results is the following: let be a bounded closed convex subset of a uniformly smooth Banach space . Let be an infinite family of commuting nonexpansive mappings on . Let and be sequences in satisfying for . Fix and define a sequence in by for . Then converges strongly to , where is the unique sunny nonexpansive retraction from onto .
Mann Type Implicit Iteration Approximation for Multivalued Mappings in Banach Spaces
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Huimin He
2010-01-01
Full Text Available Let K be a nonempty compact convex subset of a uniformly convex Banach space E and let T be a multivalued nonexpansive mapping. For the implicit iterates x0?K, xn=?nxn-1+(1-?nyn, yn?Txn, n?1. We proved that {xn} converges strongly to a fixed point of T under some suitable conditions. Our results extended corresponding ones and revised a gap in the work of Panyanak (2007.
Embedding theorems in Banach-valued -spaces and maximal -regular differential-operator equations
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Shakhmurov Veli B
2006-01-01
Full Text Available The embedding theorems in anisotropic Besov-Lions type spaces are studied; here and are two Banach spaces. The most regular spaces are found such that the mixed differential operators are bounded from to , where are interpolation spaces between and depending on and . By using these results the separability of anisotropic differential-operator equations with dependent coefficients in principal part and the maximal -regularity of parabolic Cauchy problem are obtained. In applications, the infinite systems of the quasielliptic partial differential equations and the parabolic Cauchy problems are studied.
Scientific Electronic Library Online (English)
Elke, Wolf.
Full Text Available SciELO Chile | Language: English Abstract in spanish Sea X y Y espacios de Banach complejos, B X y B Y las bolas unitarias cerradas correspondientes. Las aplicaciones analíticas : B Y [...] width=29 height=24 id="_x0000_i1044" src="http:/fbpe/img/cubo/v15n2/art04-02.jpg" alt="Descripción: http:/fbpe/img/cubo/v15n2/art04-02.jpg">B X y: B X inducen el operador de composición con pesos: C , : H (B Y) H (Bx), f (f o ), donde H (B Y) y H (Bx) denotan la colección de todas las funciones analíticas f : Bx (resp. B Y) . Estudiamos cuándo dichos operadores que actúan entre los espacios con peso de funciones analíticas son isométricas. Abstract in english Let X and Y be complex Banach spaces and B X resp. B Y the closed unit ball. Analytic maps : B Y [...] " src="http:/fbpe/img/cubo/v15n2/art04-02.jpg" alt="Descripción: http:/fbpe/img/cubo/v15n2/art04-02.jpg">B X and : B X induce the weighted composition operator: C , : H (B Y) H (Bx), f (f o ), where H (B Y) resp. H (Bx) denotes the collection of all analytic functions f : Bx (resp. B Y) . We study when such operators acting between weighted spaces of analytic functions are isometric.
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Liu Min
2010-01-01
Full Text Available We prove a strong convergence theorem by using a hybrid method for finding a common element of the set of solutions for generalized mixed equilibrium problems, the set of fixed points of a family of quasi- -asymptotically nonexpansive mappings in strictly convex reflexive Banach space with the Kadec-Klee property and, a Fréchet differentiable norm under weaker conditions. The method of the proof is different from, S. Takahashi and W. Takahashi that by (2008 and that by Takahashi and Zembayashi (2008 and see references. It also shows that the type of projection used in the iterative method is independent of the properties of the mappings. The results presented in the paper improve and extend some recent results.
A note on set-valued Henstock--McShane integral in Banach (lattice) space setting
Boccuto, Antonio; Candeloro, Domenico; Sambucini, Anna Rita
2014-01-01
We study Henstock-type integrals for functions defined in a Radon measure space and taking values in a Banach lattice $X$. Both the single-valued case and the multivalued one are considered (in the last case mainly $cwk(X)$-valued mappings are discussed). The main tool to handle the multivalued case is a R{\\aa}dstr\\"{o}m-type embedding theorem established in [50]: in this way we reduce the norm-integral to that of a single-valued function taking values in an $M$-space and we...
Nielsen, Lance
2011-12-01
In this paper we investigate the relation between weak convergence of a sequence left\\{ ?nright\\} of probability measures on a Polish space S converging weakly to the probability measure ? and continuous, norm-bounded functions into a Banach space X. We show that, given a norm-bounded continuous function f: S? X, it follows that lim_{ntoinfty}intSf d?n=intSf d?—the limit one has for bounded and continuous real (or complex)—valued functions on S. This result is then applied to the stability theory of Feynman's operational calculus where it is shown that the theory can be significantly improved over previous results.
The penalty method for variational inequalities with nonsmooth unbounded operators in Banach space
Alber, Y I
1993-01-01
The existence of a solution, convergence and stability of the penalty method for variational inequalities with nonsmooth unbounded uniformly and properly monotone operators in Banach spase $B$ are investigated. All the objects of the inequality - the operator A, "the right-hand part" $f$ and the set of constrains $\\Omega $ - are to be perturbed. The stability theorems are formulated in terms of geometric characteristics of the spaces $B$ and $B^*$. The results of this paper are continuity and generalization of the Lions' ones, published earlier in \\cite{l}. They are new even in Hilbert spaces.
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Elke Wolf
2010-01-01
Full Text Available We consider analytic self-maps ø?1,ø ?2 of the open unit disk as well as analytic maps? 1, ?2. These maps induce differences of weighted composition operators acting between weighted Banach spaces of holomorphic functions and weighted Bloch type spaces. In this article we give necessary and sufficient conditions for such a difference to be bounded resp. compact.Nosotros consideramos auto aplicaciones ø?1,ø ?2 del disco unitario abierto bien como aplicaciones analíticas ?1, ?2. Estas aplicaciones inducen diferencias de compición de operadores con peso actuando entre espacios de Banach pesados de funciones holomorfas y espacios de tipo Bloch con peso. En este artículo damos condiciones necesarias y suficientes para que tal diferencia sea acotada, respectivamente, compacta.
Double-dual n-types over Banach spaces not containing Ã¢Â„Â“1
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Markus Pomper
2004-07-01
Full Text Available Let E be a Banach space. The concept of n-type overE is introduced here, generalizing the concept of type overE introduced by Krivine and Maurey. Let EÃ¢Â€Â³ be the second dual of E and fix gÃ¢Â€Â³1,Ã¢Â€Â¦gÃ¢Â€Â³nÃ¢ÂˆÂˆEÃ¢Â€Â³. The function ÃÂ„:EÃƒÂ—Ã¢Â„ÂnÃ¢Â†Â’Ã¢Â„Â, defined by letting ÃÂ„(x,a1,Ã¢Â€Â¦,an=Ã¢Â€Â–x+Ã¢ÂˆÂ‘i=1naigÃ¢Â€Â³iÃ¢Â€Â– for all xÃ¢ÂˆÂˆE and all a1,Ã¢Â€Â¦,anÃ¢ÂˆÂˆÃ¢Â„Â, defines an n-type over E. Types that can be represented in this way are called double-dual n-types; we say that (gÃ¢Â€Â³1,Ã¢Â€Â¦gÃ¢Â€Â³nÃ¢ÂˆÂˆ(EÃ¢Â€Â³n realizes ÃÂ„. Let E be a (not necessarily separable Banach space that does not contain Ã¢Â„Â“1. We study the set of elements of (EÃ¢Â€Â³n that realize a given double-dual n-type over E. We show that the set of realizations of this n-type is convex. This generalizes a result of Haydon and Maurey who showed that the set of realizations of a given 1-type over a separable Banach space E is convex. The proof makes use of Henson's language for normed space structures and uses ideas from mathematical logic, most notably the LÃƒÂ¶wenheim-Skolem theorem.
Quasi-Banach spaces of almost universal disposition.
Czech Academy of Sciences Publication Activity Database
Sánchez, C. F.; Garbuli?ska, J.; Kubi?, Wieslaw
2014-01-01
Ro?. 267, ?. 3 (2014), s. 744-771. ISSN 0022-1236 R&D Projects: GA ?R(CZ) GAP201/12/0290 Institutional support: RVO:67985840 Keywords : p-Gurarii space * space of universal disposition * isometry Subject RIV: BA - General Mathematics Impact factor: 1.152, year: 2013 http://www.sciencedirect.com/science/article/pii/S0022123614002043
Local subdifferentials and multivariational inequalities in Banach and Frechet spaces
Kasyanov, Pavlo O.; Mel’nik, Valery S.; Piccirillo, Anna M.
2008-01-01
Some functional-topological concepts of subdifferential and locally subdifferential maps in Frechet spaces are established. Multivariational inequalities with an operator of the pseudo-monotone type, connected with subdifferential maps, are considered.
Maximal regular boundary value problems in Banach-valued function spaces and applications
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Veli B. Shakhmurov
2006-07-01
Full Text Available The nonlocal boundary value problems for differential operator equations of second order with dependent coefficients are studied. The principal parts of the differential operators generated by these problems are non-selfadjoint. Several conditions for the maximal regularity and the Fredholmness in Banach-valued Lp-spaces of these problems are given. By using these results, the maximal regularity of parabolic nonlocal initial boundary value problems is shown. In applications, the nonlocal boundary value problems for quasi elliptic partial differential equations, nonlocal initial boundary value problems for parabolic equations, and their systems on cylindrical domain are studied.
Convergence theorems for a class of nonlinear maps in uniformly smooth Banach spaces
International Nuclear Information System (INIS)
Let K be a nonempty closed and convex subset of a real uniformly smooth Banach space, E, with modulus of smoothness of power type q>1. Let T be a mapping of K into itself, T is an element of C (in the notion of Browder and Petryshyn; and Rhoades). It is proved that the Mann iteration process, under suitable conditions, converges strongly to the unique fixed point of T. If K is also bounded, then the Ishikawa iteration process converges to the fixed point of T. While our theorems generalize important known results, our method is also of independent interest. (author). 14 refs
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Zhou Yong
2011-01-01
Full Text Available Abstract The paper is devoted to the study of an approximation process of time optimal control for fractional evolution systems in Banach spaces. We firstly convert time optimal control problem into Meyer problem. By virtue of the properties of the family of solution operators given by us, the existence of optimal controls for Meyer problem is proved. Secondly, we construct a sequence of Meyer problems to successive approximation of the original time optimal control problem. Finally, a new approximation process is established to find the solution of time optimal control problem. Our method is different from the standard method.
Approximating common fixed points of two asymptotically quasi-nonexpansive mappings in Banach spaces
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Udomene Aniefiok
2006-01-01
Full Text Available Suppose is a nonempty closed convex subset of a real Banach space . Let be two asymptotically quasi-nonexpansive maps with sequences such that and , and . Suppose is generated iteratively by where and are real sequences in . It is proved that (a converges strongly to some if and only if ; (b if is uniformly convex and if either or is compact, then converges strongly to some . Furthermore, if is uniformly convex, either or is compact and is generated by , where , are bounded, are real sequences in such that and , are summable; it is established that the sequence (with error member terms converges strongly to some .
A linear regularization scheme for inverse problems with unbounded linear operators on Banach spaces
International Nuclear Information System (INIS)
This paper extends the linear regularization scheme known as the approximate inverse to unbounded linear operators on Banach spaces. The principle of feature reconstruction is adapted from bounded operators to the unbounded scenario and, in addition, a new situation is examined where the data need to be pre-processed to fit into the mathematical model. In all these cases, invariance and regularization properties are surveyed and established for the example of fractional differentiation. Numerical results confirm the derived characteristics of the presented methods. (paper)
Isometric group actions on Banach spaces and representations vanishing at infinity
Cornulier, Yves; Tessera, Romain; Valette, Alain
2006-01-01
Our main result is that the simple Lie group $G=Sp(n,1)$ acts properly isometrically on $L^p(G)$ if $p>4n+2$. To prove this, we introduce property $({\\BP}_0^V)$, for $V$ be a Banach space: a locally compact group $G$ has property $({\\BP}_0^V)$ if every affine isometric action of $G$ on $V$, such that the linear part is a $C_0$-representation of $G$, either has a fixed point or is metrically proper. We prove that solvable groups, connected Lie groups, and linear algebraic gro...
Quasi-geostrophic equations with initial data in Banach spaces of local measures
Sadek Gala
2005-01-01
This paper studies the well posedness of the initial value problem for the quasi-geostrophic type equations $$displaylines{ partial_{t}heta+u ablaheta+( -Delta) ^{gamma}heta =0 quad hbox{on }mathbb{R}^{d}imes] 0,+infty[cr heta( x,0) =heta_{0}(x), quad xinmathbb{R}^{d} }$$ where 0 less than $gammaleq 1$ is a fixed parameter and the velocity field $u=(u_{1},u_{2},dots,u_{d}) $ is divergence free; i.e., $ abla u=0)$. The initial data $heta_{0}$ is taken in Banach spaces of local measures (see ...
The Banach space $H^1(X,d,\\mu)$, II
Müller, P F X
1994-01-01
In this paper we give the isomorphic classification of atomic $H^1(X,d,\\mu)$, where $(X,d,\\mu)$ is a space of homogeneous type, hereby completing a line of investigation opened by the work of Bernard Maurey [Ma1], [Ma2], [Ma3] and continued by Lennard Carleson [C] and Przemyslaw Wojtaszczyk [Woj1], [Wpj2].
A convergence rates result for an iteratively regularized Gauss–Newton–Halley method in Banach space
Kaltenbacher, B.
2015-01-01
The use of second order information on the forward operator often comes at a very moderate additional computational price in the context of parameter identification problems for differential equation models. On the other hand the use of general (non-Hilbert) Banach spaces has recently found much interest due to its usefulness in many applications. This motivates us to extend the second order method from Kaltenbacher (2014 Numer. Math. at press), (see also Hettlich and Rundell 2000 SIAM J. Numer. Anal. 37 587620) to a Banach space setting and analyze its convergence. We here show rates results for a particular source condition and different exponents in the formulation of Tikhonov regularization in each step. This includes a complementary result on the (first order) iteratively regularized Gauss–Newton method in case of a one-homogeneous data misfit term, which corresponds to exact penalization. The results clearly show the possible advantages of using second order information, which get most pronounced in this exact penalization case. Numerical simulations for an inverse source problem for a nonlinear elliptic PDE illustrate the theoretical findings.
A perturbation result for quasi-linear stochastic differential equations in UMD Banach spaces
Cox, Sonja
2012-01-01
We consider the effect of perturbations to a quasi-linear parabolic stochastic differential equation set in a UMD Banach space $X$. To be precise, we consider perturbations of the linear part, i.e. the term concerning a linear operator $A$ generating an analytic semigroup. We provide estimates for the difference between the solution to the original equation $U$ and the solution to the perturbed equation $U_0$ in the $L^p(\\Omega;C([0,T];X))$-norm. In particular, this difference can be estimated $|| R(\\lambda:A)-R(\\lambda:A_0) ||$ for sufficiently smooth non-linear terms. The work is inspired by the desire to prove convergence of space discretization schemes for such equations. In this article we prove convergence rates for the case that $A$ is approximated by its Yosida approximation, and in a forthcoming publication we consider convergence of Galerkin and finite-element schemes in the case that $X$ is a Hilbert space.
International Nuclear Information System (INIS)
It is proved that a semilinear function on a complex banach space is not differentiable according to the usual definition of differentiability in the calculus on banch spaces. It is shown that this result makes the calculus largely inapplicable to the solution od variational problems of quantum mechanics. A new concept of differentiability called semidifferentiability is defined. This generalizes the standard concept of differentiability in a banach space and the resulting calculus is particularly suitable for optimizing real-value functions on a complex banach space and is directly applicable to the solution of quantum mechanical variational problems. As an example of such application a rigorous proof of a generalized version of a result due to Sharma (J. Phys. A; 2:413 (1969)) is given. In the course of this work a new concept of prelinearity is defined and some standard results in the calculus in banach spaces are extended and generalized into more powerful ones applicable directly to prelinear functions and hence yielding the standard results for linear function as particular cases. (author)
Ahmetoglu, Feyzullah
2011-01-01
Kuhn-Tucker conditions for mathematical programming problems in Banach spaces partially ordered by cone with empty interior are obtained under strong simultaneity condition. If partial ordered cone has interior point, it is proved that Slater and strong simultaneity conditions are equivalent.
Monotone path-connectedness and solarity of Menger-connected sets in Banach spaces
Alimov, A. R.
2014-08-01
We prove that every boundedly compact \\operatorname{m}-connected (Menger-connected) set is monotone path-connected and is a sun in a broad class of Banach spaces (in particular, in separable spaces). We show that the intersection of a boundedly compact monotone path-connected ( \\operatorname{m}-connected) set with a closed ball is cell-like (of trivial shape) and, in particular, acyclic (contractible in the finite-dimensional case) and is a sun. We also prove that every boundedly weakly compact \\operatorname{m}-connected set is monotone path-connected. In passing, we extend the Rainwater-Simons weak convergence theorem to the case of convergence with respect to the associated norm (in the sense of Brown).
Double-dual types over the Banach space C(K
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Markus Pomper
2005-10-01
Full Text Available Let K be a compact Hausdorff space and C(K the Banach space of all real-valued continuous functions on K, with the sup-norm. Types over C(K (in the sense of Krivine and Maurey can be uniquely represented by pairs (Ã¢Â„Â“,u of bounded real-valued functions on K, where Ã¢Â„Â“ is lower semicontinuous, u is upper semicontinuous, Ã¢Â„Â“Ã¢Â‰Â¤u, and Ã¢Â„Â“(x=u(x for all isolated points x of K. A condition that characterizes the pairs (Ã¢Â„Â“,u that represent double-dual types over C(K is given.
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Sangeetha Rajendran
2013-10-01
Full Text Available Classification based on supervised learning theory is one of the most significant tasks frequently accomplished by so-called Intelligent Systems. Contrary to the traditional classification techniques that are used to validate or contradict a predefined hypothesis, kernel based classifiers offer the possibility to frame new hypotheses using statistical learning theory (Sangeetha and Kalpana, 2010. Support Vector Machine (SVM is a standard kernel based learning algorithm where it improves the learning ability through experience. It is highly accurate, robust and optimal kernel based classification technique that is well-suited to many real time applications. In this paper, kernel functions related to Hilbert space and Banach Space are explained. Here, the experimental results are carried out using benchmark multiclass datasets which are taken from UCI Machine Learning Repository and their performance are compared using various metrics like support vector, support vector percentage, training time and accuracy.
Exponential stability of linear and almost periodic systems on Banach spaces
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Constantin Buse
2003-12-01
Full Text Available Let $v_f(cdot, 0$ the mild solution of the well-posed inhomogeneous Cauchy problem $$ dot v(t=A(tv(t+f(t, quad v(0=0quad tge 0 $$ on a complex Banach space $X$, where $A(cdot$ is an almost periodic (possible unbounded operator-valued function. We prove that $v_f(cdot, 0$ belongs to a suitable subspace of bounded and uniformly continuous functions if and only if for each $xin X$ the solution of the homogeneous Cauchy problem $$ dot u(t=A(tu(t, quad u(0=xquad tge 0 $$ is uniformly exponentially stable. Our approach is based on the spectral theory of evolution semigroups.
Asymptotic behaviour of solutions of nonlinear delay difference equations in Banach spaces
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Anna Kisiolek
2005-10-01
Full Text Available We consider the second-order nonlinear difference equations of the form ÃŽÂ”(rnÃ¢ÂˆÂ’1ÃŽÂ”xnÃ¢ÂˆÂ’1+pnf(xnÃ¢ÂˆÂ’k=hn. We show that there exists a solution (xn, which possesses the asymptotic behaviour Ã¢Â€Â–xnÃ¢ÂˆÂ’aÃ¢ÂˆÂ‘j=0nÃ¢ÂˆÂ’1(1/rj+bÃ¢Â€Â–=o(1, a,bÃ¢ÂˆÂˆÃ¢Â„Â. In this paper, we extend the results of Agarwal (1992, Dawidowski et al. (2001, Drozdowicz and Popenda (1987, M. Migda (2001, and M. Migda and J. Migda (1988. We suppose that f has values in Banach space and satisfies some conditions with respect to the measure of noncompactness and measure of weak noncompactness.
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Suppose E is a real uniformly smooth Banach space and K is a nonempty closed convex and bounded subset of E, T:K ? K is a Lipschitz pseudo-contraction. It is proved that the Picard iterates of a suitably defined operator converges strongly to the unique fixed point of T. Furthermore, this result also holds for the slightly larger class of Lipschitz strong hemi-contractions. Related results deal with strong convergence of the Picard iterates to the unique solution of operator equations involving Lipschitz strongly accretive maps. Apart from establishing strong convergence, our theorems give existence, uniqueness and convergence-rate which is at least as fast as a geometric progression. (author). 51 refs
Hybrid methods for accretive variational inequalities involving pseudocontractions in Banach spaces
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Chen Rudong
2011-01-01
Full Text Available Abstract We use strongly pseudocontractions to regularize a class of accretive variational inequalities in Banach spaces, where the accretive operators are complements of pseudocontractions and the solutions are sought in the set of fixed points of another pseudocontraction. In this paper, we consider an implicit scheme that can be used to find a solution of a class of accretive variational inequalities. Our results improve and generalize some recent results of Yao et al. (Fixed Point Theory Appl, doi:10.1155/2011/180534, 2011 and Lu et al. (Nonlinear Anal, 71(3-4, 1032-1041, 2009. 2000 Mathematics subject classification 47H05; 47H09; 65J15
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G. S. Saluja
2007-03-01
Full Text Available In this paper, we study strong convergence of common fixed points of two asymptotically quasi-nonexpansive mappings and prove that if $K$ is a nonempty closed convex subset of a real Banach space $E$ and let $ S, T\\colon K\\to K $ be two asymptotically quasi-nonexpansive mappings with sequences $ \\{u_n\\}$, $\\{v_n\\}\\subset [0,\\infty $ such that $ \\sum_{n=1}^{\\infty}u_n$$ \\begin{cases} x_{n+1}& = (1-\\alpha_nx_n + \\alpha_nS^ny_n + l_n \\\\ y_n &= (1-\\beta_nx_n + \\beta_nT^nx_n + m_n, \\quad \\forall n\\in N \\end{cases} $$where $ \\{l_n\\}_{n=1}^{\\infty},\\{m_n\\}_{n=1}^{\\infty} $ are sequences in $K$ satisfying $ \\sum_{n=1}^{\\infty}\\Vert l_n\\Vert
A Banach space-valued ergodic theorem for amenable groups and applications
Pogorzelski, Felix
2012-01-01
In this paper we study unimodular amenable groups. The first part is devoted to results on the existence of uniform families of quasi tilings for these groups. In light of that, constructions of Ornstein and Weiss are extended by quantitative estimates for the covering properties of the corresponding decompositions. Afterwards, we apply the developed methods to obtain an abstract ergodic theorem for a class of functions mapping subsets of the group into some Banach space. Moreover, applications of this convergence result are studied: the uniform existence of the integrated density of states (IDS) for operators on amenable Cayley graphs; the uniform existence of the IDS for operators on discrete structures being quasi-isometric to some amenable group; the approximation of L2-Betti numbers on cellular CW-complexes; the existence of certain densities of clusters in a percolated Cayley graph.
Mimura, Masato
2009-01-01
In this paper, we prove that for a unital commutative and finitely generated ring $A$, the group $G= EL_n (A)$ has a fixed point property for affine isometric actions on $B$ if $n \\geq 4$. Here $B$ stands for any $L^p$ space or any Banach space isomorphic to a Hilbert space. We also verify that the comparison map in degree 2 $\\Psi^2 \\colon H_b^2 (G,B) \\to H^2 (G,B)$ from bounded to usual cohomology is injective, where $G$ and $B$ are same as in above. For our proof, we establish a certain implication from Kazhdan's property (T) to a fixed point property on uniformly convex Banach spaces.
Quasi-geostrophic equations with initial data in Banach spaces of local measures
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Sadek Gala
2005-06-01
Full Text Available This paper studies the well posedness of the initial value problem for the quasi-geostrophic type equations $$displaylines{ partial_{t}heta+u ablaheta+( -Delta ^{gamma}heta =0 quad hbox{on }mathbb{R}^{d}imes] 0,+infty[cr heta( x,0 =heta_{0}(x, quad xinmathbb{R}^{d} }$$ where 0 less than $gammaleq 1$ is a fixed parameter and the velocity field $u=(u_{1},u_{2},dots,u_{d} $ is divergence free; i.e., $ abla u=0$. The initial data $heta_{0}$ is taken in Banach spaces of local measures (see text for the definition, such as Multipliers, Lorentz and Morrey-Campanato spaces. We will focus on the subcritical case 1/2 less than $gammaleq1$ and we analyse the well-posedness of the system in three basic spaces: $L^{d/r,infty}$, $dot {X}_{r}$ and $dot {M}^{p,d/r}$, when the solution is global for sufficiently small initial data. Furtheremore, we prove that the solution is actually smooth. Mild solutions are obtained in several spaces with the right homogeneity to allow the existence of self-similar solutions.
International Nuclear Information System (INIS)
Let E be a real uniformly convex Banach space whose dual space E* satisfies the Kadec- Klee property, K be a closed convex nonempty subset of E . Let T1, T2, . . . , Tm : K ? K be asymptotically nonexpansive mappings of K into E with sequences (respectively) {kin}n=1? satisfying kin ? 1 as n ? ?, i = 1, 2 , ...,m and ?n=1?(kin - 1) in}n=1? be a sequence in [?, 1 - ? ], for each i element of { 1, 2 , . . . ,m} (respectively). Let {xn} be a sequence generated for m ? 2 by, x1 element of K, xn+1 = (1 - ?1n)xn + ?1nT1nyn+m-2, yn+m-2 = (1 - ?2n)xn + ?2nT2nyn+m-3, ..., yn = (1 - ?mn)xn + ?mnTmnxn , n ? 1. Let Intersectioni=1m F (Ti) ? 0 . Then, {xn} converges weakly to a common fixed point of the family {Ti}i=1m. Under some appropriate condition on the family {Ti}i=1m, a strong convergence theorem is also roved. (author)
Liu, Lishan; Wu, Yonghong; Zhang, Xinguang
2006-05-01
In this paper, we develop an existence and uniqueness theorem of the solution to an initial value problems for a class of second-order impulsive integro-differential equations of Volterra type in a real Banach space by using the generalized Banach fixed point theorem. An explicit iterative scheme for the solution and an error estimate of the approximation sequence for the initial value problem are also derived. Two examples are presented to demonstrate the application of our results.
Strong Convergence of a New Three Step Iterative Scheme in Banach Spaces
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Renu Chugh
2012-12-01
Full Text Available
In this paper, we suggest a new type of three step iterative scheme called the CR iterative scheme and study the strong convergence of this iterative scheme for a certain class of quasi-contractive operators in Banach spaces. We show that for the aforementioned class of operators, the CR iterative scheme is equivalent to and faster than Picard, Mann, Ishikawa, Agarwal et al., Noor and SP iterative schemes. Moreover, we also present various numerical examples using computer programming in C++ for the CR iterative scheme to compare it with the other above mentioned iterative schemes. Our results show that as far as the rate of convergence is concerned 1 for increasing functions the CR iterative scheme is best, while for decreasing functions the SP iterative scheme is best; 2 CR iterative scheme is best for a certain class of quasi-contractive operators.
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Microwave imaging apparatuses have become very important tools in the framework of imaging systems. However, particular care must be taken when developing the data-processing algorithm needed to solve the underlying nonlinear and ill-posed inverse problem. Usually, regularization techniques developed in the framework of Hilbert spaces are used. In this paper, a new approach based on a regularization in the framework of Lp Banach spaces is considered, and its performances are evaluated by considering a reference canonical target with elliptical cross section. (paper)
Demand functions and reflexivity
Polyrakis, Ioannis A.
2008-02-01
In the theory of ordered spaces and in microeconomic theory two important notions, the notion of the base for a cone which is defined by a continuous linear functional and the notion of the budget set are equivalent. In economic theory the maximization of the preference relation of a consumer on any budget set defines the demand correspondence which at any price vector indicates the preferred vectors of goods and this is one of the fundamental notions of this theory. Contrary to the finite-dimensional economies, in the infinite-dimensional ones, the existence of the demand correspondence is not ensured. In this article we show that in reflexive spaces (and in some other classes of Banach spaces), there are only two classes of closed cones, i.e. cones whose any budget set is bounded and cones whose any budget set is unbounded. Based on this dichotomy result, we prove that in the first category of these cones the demand correspondence exists and that it is upper hemicontinuous. We prove also a characterization of reflexive spaces based on the existence of the demand correspondences.
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D. A. Robbins
1994-12-01
Full Text Available We study bundles of Banach algebras ÃÂ€:AÃ¢Â†Â’X, where each fiber Ax=ÃÂ€Ã¢ÂˆÂ’1({x} is a Banach algebra and X is a compact Hausdorff space. In the case where all fibers are commutative, we investigate how the Gelfand representation of the section space algebra ÃŽÂ“(ÃÂ€ relates to the Gelfand representation of the fibers. In the general case, we investigate how adjoining an identity to the bundle ÃÂ€:AÃ¢Â†Â’X relates to the standard adjunction of identities to the fibers.
Gorbachuk, Myroslav L.; Gorbachuk, Valentyna I.
2003-01-01
For the Cauchy problem for an operator differential equation of the form $y'(z) = Ay(z)$, where $A$ is a closed linear operator on a Banach space over the completion of an algebraic closure of the field of $p$-adic numbers, a criterion of correct solvability in the class of locally analytic vector-functions is established. It is shown how the Cauchy-Kovalevskaya theorem for $p$-adic partial differential equations may be obtained as a particular case from this criterion.
ON THE LOCAL CONVERGENCE OF A MIDPOINT METHOD IN BANACH SPACES UNDER A GAMMA-TYPE CONDITION
Scientific Electronic Library Online (English)
Ioannis K, Argyros.
2009-08-01
Full Text Available SciELO Chile | Language: English Abstract in english In this study we are concerned with the problem of approximating a locally unique solution of an operator equation in a Banach space setting using the midpoint method, introduced by us in [5], [6]. Here, we use gamma-type condition to provide a local convergence analysis. Our results compare favorab [...] ly with the relevant ones in [9], [11], [12]-[14]- In particular our radius of convergence is larger. Numerical examples are also provided.
Fry, R.; Keener, L.
2009-01-01
This note corrects a gap and improves results in an earlier paper by the first named author. More precisely, it is shown that on weakly compactly generated Banach spaces X which admit a C^{p} smooth norm, one can uniformly approximate uniformly continuous functions f:X->R by Lipschitz, C^{p} smooth functions. Moreover, there is a constant C>1 so that any L-Lipschitz function f:X->R can be uniformly approximated by CL-Lipschitz, C^{p} smooth functions. This provides a ...
A Variational Principle in Reflexive Spaces with Kadec-Klee Norm.
Czech Academy of Sciences Publication Activity Database
Fabian, Marián; Revalski, J. P.
2009-01-01
Ro?. 16, ?. 1 (2009), s. 211-226. ISSN 0944-6532 R&D Projects: GA ?R GA201/04/0090 Institutional research plan: CEZ:AV0Z10190503 Keywords : reflexive space * Kadec- Klee norm * variational principle * perturbed function * well-posed infimum Subject RIV: BA - General Mathematics Impact factor: 0.813, year: 2009
Ring homomorphisms on real Banach algebras
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Sin-Ei Takahasi
2003-08-01
Full Text Available Let B be a strictly real commutative real Banach algebra with the carrier space ÃŽÂ¦B. If A is a commutative real Banach algebra, then we give a representation of a ring homomorphism ÃÂ:AÃ¢Â†Â’B, which needs not be linear nor continuous. If A is a commutative complex Banach algebra, then ÃÂ(A is contained in the radical of B.
Hoop, Maarten V.; Qiu, Lingyun; Scherzer, Otmar
2012-01-01
We consider nonlinear inverse problems described by operator equations in Banach spaces. Assuming conditional stability of the inverse problem, that is, assuming that stability holds on a closed, convex subset of the domain of the operator, we introduce a novel nonlinear projected steepest descent iteration and analyze its convergence to an approximate solution given limited accuracy data. We proceed with developing a multi-level algorithm based on a nested family of closed,...
International Nuclear Information System (INIS)
The notion of a 2-Banach algebra is introduced and its structure is studied. After a short discussion of some fundamental properties of bivectors and tensor product, several classical results of Banach algebras are extended to the 2-Banach algebra case. A condition under which a 2-Banach algebra becomes a Banach algebra is obtained and the relation between algebra of bivectors and 2-normed algebra is discussed. 11 refs
Zeng, Lu-Chuan; Yao, Jen-Chih
2006-09-01
Recently, Agarwal, Cho, Li and Huang [R.P. Agarwal, Y.J. Cho, J. Li, N.J. Huang, Stability of iterative procedures with errors approximating common fixed points for a couple of quasi-contractive mappings in q-uniformly smooth Banach spaces, J. Math. Anal. Appl. 272 (2002) 435-447] introduced the new iterative procedures with errors for approximating the common fixed point of a couple of quasi-contractive mappings and showed the stability of these iterative procedures with errors in Banach spaces. In this paper, we introduce a new concept of a couple of q-contractive-like mappings (q>1) in a Banach space and apply these iterative procedures with errors for approximating the common fixed point of the couple of q-contractive-like mappings. The results established in this paper improve, extend and unify the corresponding ones of Agarwal, Cho, Li and Huang [R.P. Agarwal, Y.J. Cho, J. Li, N.J. Huang, Stability of iterative procedures with errors approximating common fixed points for a couple of quasi-contractive mappings in q-uniformly smooth Banach spaces, J. Math. Anal. Appl. 272 (2002) 435-447], Chidume [C.E. Chidume, Approximation of fixed points of quasi-contractive mappings in Lp spaces, Indian J. Pure Appl. Math. 22 (1991) 273-386], Chidume and Osilike [C.E. Chidume, M.O. Osilike, Fixed points iterations for quasi-contractive maps in uniformly smooth Banach spaces, Bull. Korean Math. Soc. 30 (1993) 201-212], Liu [Q.H. Liu, On Naimpally and Singh's open questions, J. Math. Anal. Appl. 124 (1987) 157-164; Q.H. Liu, A convergence theorem of the sequence of Ishikawa iterates for quasi-contractive mappings, J. Math. Anal. Appl. 146 (1990) 301-305], Osilike [M.O. Osilike, A stable iteration procedure for quasi-contractive maps, Indian J. Pure Appl. Math. 27 (1996) 25-34; M.O. Osilike, Stability of the Ishikawa iteration method for quasi-contractive maps, Indian J. Pure Appl. Math. 28 (1997) 1251-1265] and many others in the literature.
Strong Convergence of CesÃƒÂ ro Mean Iterations for Nonexpansive Nonself-Mappings in Banach Spaces
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Rabian Wangkeeree
2007-10-01
Full Text Available Let E be a real uniformly convex Banach space which admits a weakly sequentially continuous duality mapping from E to E*, C a nonempty closed convex subset of E which is also a sunny nonexpansive retract of E, and T:CÃ¢Â†Â’E a non-expansive nonself-mapping with F(TÃ¢Â‰Â Ã¢ÂˆÂ…. In this paper, we study the strong convergence of two sequences generated by xn+1=ÃŽÂ±nx+(1Ã¢ÂˆÂ’ÃŽÂ±n(1/n+1Ã¢ÂˆÂ‘j=0n(PTjxn and yn+1=(1/n+1Ã¢ÂˆÂ‘j=0nP(ÃŽÂ±ny+(1Ã¢ÂˆÂ’ÃŽÂ±n(TPjyn for all nÃ¢Â‰Â¥0, where x,x0,y,y0Ã¢ÂˆÂˆC, {ÃŽÂ±n} is a real sequence in an interval [0,1], and P is a sunny non-expansive retraction of E onto C. We prove that {xn} and {yn} converge strongly to Qx and Qy, respectively, as nÃ¢Â†Â’Ã¢ÂˆÂž, where Q is a sunny non-expansive retraction of C onto F(T. The results presented in this paper generalize, extend, and improve the corresponding results of Matsushita and Kuroiwa and many others.
Some Extensions of Banach's Contraction Principle in Complete Cone Metric Spaces
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Raja P
2008-01-01
Full Text Available Abstract In this paper we consider complete cone metric spaces. We generalize some definitions such as -nonexpansive and -uniformly locally contractive functions -closure, -isometric in cone metric spaces, and certain fixed point theorems will be proved in those spaces. Among other results, we prove some interesting applications for the fixed point theorems in cone metric spaces.
Critical values of functionals on Banach surfaces
International Nuclear Information System (INIS)
In this paper we define the directional differentiability along a dense linear subspace D of a Banach space E and study the critical values of D-differentiable functionals on surfaces in E. (author). 11 refs
Stochastic integration in Banach spaces and applications to parabolic evolution equations:
Veraar, M. C.
2006-01-01
Stochastic partial differential equations (SPDEs) of evolution type are usually modelled as ordinary stochastic differential equations (SDEs) in an infinite-dimensional state space. In many examples such as the stochastic heat and wave equation, this viewpoint may lead to existence and uniqueness results and regularity properties. To model the equation in such a way one needs a stochastic integration theory for processes with values in an infinite-dimensional space. This approach has been con...
Botelho, Fabio
2014-01-01
This book introduces the basic concepts of real and functional analysis. It presents the fundamentals of the calculus of variations, convex analysis, duality, and optimization that are necessary to develop applications to physics and engineering problems. The book includes introductory and advanced concepts in measure and integration, as well as an introduction to Sobolev spaces. The problems presented are nonlinear, with non-convex variational formulation. Notably, the primal global minima may not be attained in some situations, in which cases the solution of the dual problem corresponds to an appropriate weak cluster point of minimizing sequences for the primal one. Indeed, the dual approach more readily facilitates numerical computations for some of the selected models. While intended primarily for applied mathematicians, the text will also be of interest to engineers, physicists, and other researchers in related fields.
Structure of biprojective Banach algebras with non-trivial radical
Energy Technology Data Exchange (ETDEWEB)
Aristov, O Yu [Obninsk State Technical University for Nuclear Power Engineering, Obninsk, Kaluzhskaya obl. (Russian Federation)
2008-12-31
We study the structure of biprojective Banach algebras. In contrast to earlier results of Selivanov, we admit the presence of nilpotent ideals in the algebras under consideration, and the structure theorem covers almost all known examples. As a corollary, we obtain a complete classification of finite-dimensional biprojective Banach algebras. A major role in the proof is played by the approximation property for certain Banach spaces related to the algebras under consideration.
n-Approximately Weak Amenability of Banach Algebras
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H. Najafi
2009-01-01
Full Text Available We introduce new notions of approximate amenability for a Banach algebra A. A Banach algebra A is n-approximately weakly amenable, for n ? N, if every continuous derivation from A into the n-th dual space A(n is approximately inner. First we examine the relation between m-approximately weak amenability and n-approximately weak amenability for distinct m,n ? N. Then we investigate (2n+1-approximately weak amenability of module extension Banach algebras. Finally, we give an example of a Banach algebra that is 1-approximately weakly amenable but not 3-approximately weakly amenable.
Scientific Electronic Library Online (English)
William, Dimbour; Jean-Claude, Mado.
Full Text Available SciELO Chile | Language: English Abstract in spanish En este artículo entregamos algunas condiciones suficientes para la existencia y unicidad de las soluciones mild ?-periódicas S-asintóticas para una ecuación diferencial semilineal con argumento constante por tramos en un espacio de Banach cuando ? es un entero. Luego, entregamos ejemplos para ilust [...] rar nuestros resultados. Abstract in english In this paper, we give some sufficient conditions for the existence and uniqueness of S-asymptotically ?-periodic (mild) solutions for a differential equation with piecewise constant argument, when ? is an integer. An example is also given in order to illustrate the result. [...
Knee Jerk Reflex (Patellar Reflex)
2012-06-26
In this quick and simple activity about reflexes (third activity on the page), learners conduct a simple test to explore the knee jerk reflex, typically conducted at the doctor's office. In this version, learners work in pairs and use their hand to prompt the reflex (not a hammer!). This activity is one of several activities featured on this webpage related to human reflexes.
Reduction of Lie–Jordan Banach algebras and quantum states
International Nuclear Information System (INIS)
In this paper, it is shown that the concept of dynamical correspondence for Jordan Banach algebras is equivalent to a Lie structure compatible with the Jordan one. Then a theory of reduction of Lie–Jordan Banach algebras in the presence of quantum constraints is presented and compared to the standard reduction of C*-algebras of observables of a quantum system. The space of states of the reduced Lie–Jordan Banach algebra is characterized in terms of Dirac states on the physical algebra of observables and its GNS representations described in terms of states on the unreduced algebra. (paper)
Escassut, Alain
2003-01-01
In this book, ultrametric Banach algebras are studied with the help of topological considerations, properties from affinoid algebras, and circular filters which characterize absolute values on polynomials and make a nice tree structure. The Shilov boundary does exist for normed ultrametric algebras. In uniform Banach algebras, the spectral norm is equal to the supremum of all continuous multiplicative seminorms whose kernel is a maximal ideal. Two different such seminorms can have the same kernel. Krasner-Tate algebras are characterized among Krasner algebras, affinoid algebras, and ultrametri
Wood, Scott J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.
2009-01-01
Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, less than 20 cm radius), the effects of stimulus frequency (0.15 - 0.6 Hz) are examined on eye movements and motion perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. One result of this study will be to characterize the variability (gain, asymmetry) in both otolith-ocular responses and motion perception during variable radius centrifugation, and measure the time course of post-flight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved with vibrotactile feedback of orientation.
Peterka, Robert J.
Recent studies by Diamond and Markham 1,2 have identified significant correlations between space motion sickness susceptibility and measures of disconjugate torsional eye movements recorded during parabolic flights. These results support an earlier proposal by von Baumgarten and Thümler 3 which hypothesized that an asymmetry of otolith function between the two ears is the cause of space motion sickness. It may be possible to devise experiments that can be performed in the 1 g environment on earth that could identify and quantify the presence of asymmetric otolith function. This paper summarizes the known physiological and anatomical properties of the otolith organs and the properties of the torsional vestibulo-ocular reflex which are relevant to the design of a stimulus to identify otolith asymmetries. A specific stimulus which takes advantage of these properties is proposed.
An algebraic property of an isometry between the groups of invertible elements in Banach algebras
Hatori, Osamu
2009-01-01
We show that if $T$ is an isometry (as metric spaces) between the invertible groups of unital Banach algebras, then $T$ is extended to a surjective real-linear isometry up to translation between the two Banach algebras. Furthermore if the underling algebras are closed unital standard operator algebras, $(T(e_A))^{-1}T$ is extended to a surjective real algebra isomorphism; if $T$ is a surjective isometry from the invertible group of a unital commutative Banach algebra onto th...
Module amenability for Banach modules
Scientific Electronic Library Online (English)
D, Ebrahimi Bagha; M, Amini.
2011-06-01
Full Text Available SciELO Chile | Language: English Abstract in spanish Se estudia el módulo de receptividad de los módulos de Banach. Esta es una generalización natural de la receptividad de Johnson de las álgebras de Banach. Como ejemplo se muestra que para un grupo abeliano discreto G l p(G) es receptivo como un G l p(G)- módulo, si y sólo si G es receptivo, donde l¹ [...] (G) es un álgebra de Banach con producto punto. Abstract in english We study the module amenability of Banach modules. This is a natural generalization of Johnson’s amenability of Banach algebras. As an example we show that for a discrete abelian group G, l p(G) is amenable as an l¹(G)-module if and only if G is amenable, where l¹(G) is a Banach algebra with pointwi [...] se multiplication.
Zegeye, Habtu; Shahzad, Naseer
2014-01-01
We introduce an iterative process for finding an element of a common fixed point of a finite family of Bregman weak relatively nonexpansive mappings. Our theorems improve and unify most of the results that have been proved for this important class of nonlinear operators. PMID:24757423
Fibrations on Banach manifolds
Gutu?, Olivia; Jaramillo Aguado, Jesu?s A?ngel
2004-01-01
Let f be a split submersion between paracompact Banach manifolds. We obtain here various conditions for f to be a fiber bundle. First, we give general conditions in terms of path-liftings. As a consequence, we deduce several criteria: For example, f is a fiber bundle provided it satisfies either some topological requirements ( such as being a proper or a closed map) or, in the case of Finsler manifolds, some metric requirements (such as Hadamard integral condition).
International Nuclear Information System (INIS)
From a special class of systems has been used the linear homogeneous differential equations with impulse effect in Minkowski space field theory with time dependent boundary conditions, i.e. those of moving mirrors. The field theoretical approach for studing the properties of the vacuum starts from an analysis of the behaviour of local field quantities in Minkowski space with uniformly moving mirrors. For the impulsive moving mirror model is the real process of interaction between the quantum field and the external mirror a subject to disturbances in its evolution acting in time very short compared with the entire duration of the process. The stability of the process in the stability of the vacuum state energy. 7 refs
Directory of Open Access Journals (Sweden)
Hacer Bozdemir
2009-04-01
Full Text Available Reflex epilepsies are induced by specific stimulants. Stimulants could be simple or complex as well as from intrinsic or extrinsic sources. The prevelance of reflex epilepsies among epilepsy patients is 4-7%. The most common form is photosensitive epilepsy. The treatment is composed of primarily avoidance from the inducer and usage of antiepileptic drugs. [Archives Medical Review Journal 2009; 18(2.000: 70-90
Directory of Open Access Journals (Sweden)
Zhang Peiguo
2011-01-01
Full Text Available Abstract By obtaining intervals of the parameter ?, this article investigates the existence of a positive solution for a class of nonlinear boundary value problems of second-order differential equations with integral boundary conditions in abstract spaces. The arguments are based upon a specially constructed cone and the fixed point theory in cone for a strict set contraction operator. MSC: 34B15; 34B16.
Spherical isometries are reflexive
Didas, Michael
2004-01-01
Let H be a complex Hilbert space. A commuting system T=(T_{1},...,T_{n}) of bounded linear operators on H is called a spherical isometry if T_{1}^{\\star}T_{1}+T_{2}^{\\star}T_{2}+\\cdots+T_{n}^{\\star}T_{n}=1_{H}. In this note we prove that each spherical isometry is reflexive.
The Reflexive Adaptations of School Principals in a "Local" South African Space
Fataar, Aslam
2009-01-01
This paper is an analysis of the work of three principals in an impoverished black township in post-apartheid South Africa. Based on qualitative approaches, it discusses the principals' entry into the township, and their navigation of their schools' surrounding social dynamics. It combines the lenses of "space" and "performance" to analyse the…
Voiculescu, Dan-virgil
2011-01-01
Is there a mod Hilbert-Schmidt analogue of the BDF-theorem, with the Pincus g-function playing the role of the index ? We show that part of the question is about the K-theory of certain Banach algebras. These Banach algebras, related to Lipschitz functions and dirichlet algebras have nice Banach space duality properties. Moreover their corona algebras are C*-algebras.
Tensor products of abstract Besov spaces
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Dmytryshyn M.I.
2012-12-01
Full Text Available We prove the interpolation theorem for tensor products of abstract Besov spaces, associated with closed operators in Banach spaces and show its application to the problems of approximations of elements of tensor products of Banach spaces.
Derivation into duals of ideals of Banach algebras
Gorgi, M E
2005-01-01
We introduce two notions of amenability for a Banach algebra $\\cal A$. Let $I$ be a closed two-sided ideal in $\\cal A$, we say $\\cal A$ is $I$-weakly amenable if the first cohomology group of $\\cal A$ with coefficients in the dual space $I^*$ is zero; i.e., $H^1({\\cal A},I^*)=\\{0\\}$, and, $\\cal A$ is ideally amenable if $\\cal A$ is $I$-weakly amenable for every closed two-sided ideal $I$ in $\\cal A$. We relate these concepts to weak amenability of Banach algebras. We also show that ideal amenability is different from amenability and weak amenability. We study the $I$-weak amenability of a Banach algebra $\\cal A$ for some special closed two-sided\\break ideal $I$.
Additive Functional Inequalities in Banach Modules
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An JongSu
2008-01-01
Full Text Available Abstract We investigate the following functional inequality in Banach modules over a -algebra and prove the generalized Hyers-Ulam stability of linear mappings in Banach modules over a -algebra in the spirit of the Th. M. Rassias stability approach. Moreover, these results are applied to investigate homomorphisms in complex Banach algebras and prove the generalized Hyers-Ulam stability of homomorphisms in complex Banach algebras.
Marlene Y. MacLeish
2012-06-26
In this activity about the baroreceptor reflex (BR) arc (page 123 of the PDF), learners discover the importance of maintaining adequate arterial blood pressure through a role playing exercise. This activity will model how the brain processes information and sends out signals to the heart and arteries. Learners can also consider how this affects astronauts in the microgravity environment of space. The lesson guide, part of NASA's "The Brain in Space: A Teacher's Guide with Activities for Neuroscience," includes background information and evaluation strategies. Note: this activity requires 9 learners per group.
Endomorphic Elements in Banach Algebras
Babalola, V A
2004-01-01
The use of the properties of actions on an algebra to enrich the study of the algebra is well-trodden and still fashionable. Here, the notion and study of endomorphic elements of (Banach) algebras are introduced. This study is initiated, in the hope that it will open up, further, the structure of (Banach) algebras in general, enrich the study of endomorphisms and provide examples. In particular, here, we use it to classify algebras for the convenience of our study. We also present results on the structure of some classes of endomorphic elements and bring out the contrast with idempotents.
??C*-????????????????? A Note on the Operator Space Projective Tensor Product of C*-Algebras
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???
2013-05-01
Full Text Available ??C*-??????????Banach*-??????????????C*-??????????????*-???????Banach*-????????????????????????????????For C*-algebras and , we discuss some properties of the Banach*-algebra . Then, we prove that the operator space projective tensor product of C*-algebras preserves *-homomorphism and a universal property of Banach*-algebra will be given. At last, a characterization of the convergence property of dual space is also obtained.
Wagon, Stan
1985-01-01
The Banach-Tarski paradox is a most striking mathematical construction: it asserts that a solid ball may be taken apart into finitely many pieces that can be rearranged using rigid motions to form a ball twice as large as the original. This volume explore
Integrability of weak distributions on Banach manifolds
Pelletier, Fernand
2010-01-01
This paper concerns the problem of integrability of non closed distributions on Banach manifolds. We introduce the notion of weak distribution and we look for conditions under which these distributions admit weak integral submanifolds. We give some applications to Banach Lie algebroid and Banach Lie-Poisson manifold. The main results of this paper generalize the works presented in [ChSt], [Nu] and [Gl].
Several complex variables and Banach algebras
International Nuclear Information System (INIS)
This paper aims to present certain applications of the theory of holomorphic functions of several complex variables to the study of commutative Banach algebras. The material falls into the following sections: (A) Introcution to Banach algebras (this will not presuppose any knowledge of the subject); (B) Groups of differential forms (mainly concerned with setting up a useful language); (C) Polynomially convex domains. (D) Holomorphic functional calculus for Banach algebras; (E) Some applications of the functional calculus. (author)
Asymptotically Pseudocontractions, Banach Operator Pairs and Best Simultaneous Approximations
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Hussain N
2011-01-01
Full Text Available The existence of common fixed points is established for the mappings where is asymptotically -pseudo-contraction on a nonempty subset of a Banach space. As applications, the invariant best simultaneous approximation and strong convergence results are proved. Presented results are generalizations of very recent fixed point and approximation theorems of Khan and Akbar (2009, Chen and Li (2007, Pathak and Hussain (2008, and several others.
Compact failure of multiplicativity for linear maps between Banach algebras
Heath, M J
2009-01-01
We introduce notions of compactness and weak compactness for multilinear maps from a product of normed spaces to a normed space, and prove some general results about these notions. We then consider linear maps $T:A\\to B$ between Banach algebras that are "close to multiplicative" in the following senses: the failure of multiplicativity, defined by $S_T(a,b)=T(a)T(b)-T(ab)$, is compact [respectively weakly compact]. We call such maps cf-homomorphisms [respectively wcf-homomorphisms]. We also introduce a number of other, related definitions. We state and prove some general theorems about these maps when they are bounded, showing that they form categories and are closed under inversion of mappings and we give a variety of examples. We then turn our attention to commutative $C^*$-algebras and show that the behaviour of the various types of "close-to-multiplicative" maps depends on the existence of isolated points. Finally, we look at the splitting of Banach extensions when considered in the category of Banach alge...
Scientific Electronic Library Online (English)
DIOMEDES, BARCENAS; WALTER, ESPINOZA; EDIXON, ROJAS.
2008-06-15
Full Text Available En este artículo se prueba que algunas álgebras de Banach clásicas no son isomorfas a un álgebra de grupo. Estas álgebras incluyen a las álgebras C(K) donde K es un espacio de Hausdorff Compacto. En el caso de las amalgamas, damos condiciones para que una amalgama sea un álgebra de grupo. [...] Abstract in english It is proved in this paper that several classical Banach algebras are not isomorphic to a group algebra. These algebras includes C(K) algebras where K is a compact Hausdorff space. In the case of amalgams, we give conditions for an amalgam to be a group algebra. [...
Modern methods in topological vector spaces
Wilansky, Albert
2013-01-01
Designed for a one-year course in topological vector spaces, this text is geared toward advanced undergraduates and beginning graduate students of mathematics. The subjects involve properties employed by researchers in classical analysis, differential and integral equations, distributions, summability, and classical Banach and Frechét spaces. Optional problems with hints and references introduce non-locally convex spaces, Köthe-Toeplitz spaces, Banach algebra, sequentially barrelled spaces, and norming subspaces.Extensive introductory chapters cover metric ideas, Banach space, topological vect
Order-type Henstock and McShane integrals in Banach lattice setting
Candeloro, Domenico; Sambucini, Anna Rita
2014-01-01
We study Henstock-type integrals for functions defined in a compact metric space $T$ endowed with a regular $\\sigma$-additive measure $\\mu$, and taking values in a Banach lattice $X$. In particular, the space $[0,1]$ with the usual Lebesgue measure is considered.
Emotionally Colorful Reflexive Games
Tarasenko, Sergey
2011-01-01
This study addresses the matter of reflexive control of the emotional states by means of Reflexive Game Theory (RGT). It is shown how to build a bridge between RGT and emotions. For this purpose the Pleasure-Arousal-Dominance (PAD) model is adopted. The major advantages of RGT are its ability to predict human behavior and unfold the entire spectra of reflexion in the human mind. On the other hand, PAD provides ultimate approach to model emotions. It is illustrated that emotions are reflexive processes and, consequently, RGT fused with PAD model is natural solution to model emotional interactions between people. The fusion of RGT and PAD, called Emotional Reflexive Games (ERG), inherits the key features of both components. Using ERG, we show how reflexive control can be successfully applied to model human emotional states. Up to date, EGR is a unique methodology capable of modeling human reflexive processes and emotional aspects simultaneously.
GK-12 Program, Computational Neurobiology Center,
Students learn about human reflexes, how our bodies react to stimuli and how some body reactions and movements are controlled automatically, without thinking consciously about the movement or responses. In the associated activity, students explore how reflexes work in the human body by observing an involuntary human reflex and testing their own reaction times using dominant and non-dominant hands. Once students understand the stimulus-to-response framework components as a way to describe human reflexes and reactions in certain situations, they connect this knowledge to how robots can be programmed to conduct similar reactions.
Banach–Mazur Distance Between Convex Quadrangles
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Lassak Marek
2014-12-01
Full Text Available It is proved that the Banach-Mazur distance between arbitrary two convex quadrangles is at most 2. The distance equals 2 if and only if the pair of these quadrangles is a parallelogram and a triangle.
The Kaplan Extension of the Ring and Banach Algebra of Continuous Functions as a Divisible Hull
Zakharov, V. K.
1995-06-01
The new algebraic structure of c-rings and c-algebras with a refinement is introduced, and on its basis the concept of a divisible hull of graduated type. These concepts are used to obtain a ring and Banach algebra characterization of the universally measurable extension C \\rightarrowtail UM as a certain type of divisible hull of the ring and Banach algebra C of all bounded continuous functions on an Aleksandrov space (Theorem 1). For purposes of comparison a description of the Arens second dual extension C\\rightarrowtail C'' is given without proof (Theorem 2).
Isometries and Isomorphisms in quasi-Banach algebras
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Zhihua Wang
2011-09-01
Full Text Available In this paper, we prove the Hyers-Ulam-Rassias stability of isometries and of homomorphisms for additive functional equations in quasi-Banach algebras. This is applied to investigate isomorphisms between quasi-Banach algebras.
Volitional control of reflex cough
Hegland, Karen W.; Bolser, Donald C.; Davenport, Paul W.
2012-01-01
Multiple studies suggest a role for the cerebral cortex in the generation of reflex cough in awake humans. Reflex cough is preceded by detection of an urge to cough; strokes specifically within the cerebral cortex can affect parameters of reflex cough, and reflex cough can be voluntarily suppressed. However, it is not known to what extent healthy, awake humans can volitionally modulate the cough reflex, aside from suppression. The aims of this study were to determine whether conscious humans ...
Lipschitz extension of multiple Banach-valued functions in the sense of Almgren
Goblet, J
2006-01-01
A multiple-valued function $f:X\\to {\\bf Q}_Q(Y)$ is essentially a rule assigning $Q$ unordered and non necessarily distinct elements of $Y$ to each element of $X$. We study the Lipschitz extension problem in this context by using two general Lipschitz extension theorems recently proved by U. Lang and T. Schlichenmaier. We prove that the pair $(X,{\\bf Q}_Q(Y))$ has the Lipschitz extension property if $Y$ is a Banach space and $X$ is a metric space with a finite Nagata dimension. We also show that ${\\bf Q}_{Q}(Y)$ is an absolute Lipschitz retract if $Y$ is a finite algebraic dimensional Banach space.
Trigeminocardiac reflex: current trends.
Chowdhury, Tumul; Sandu, Nora; Sadr-Eshkevari, Pooyan; Meuwly, Cyrill; Schaller, Bernhard
2014-01-01
Since the first introduction of the trigeminocardiac reflex (TCR) in 1999, substantial new knowledge about this brainstem reflex has been created. First, by different clinical case reports and case studies, and second, from basic research that gives inputs from bench to bedside. In the present work, the authors therefore introduce the molecular/anatomical knowledge of the TCR and show its different connections to clinical aspects. Special reference is given to prevention and treatment of the TCR; but always with a link to knowledge of the basis sciences. In such a context different topics of future interest are introduced. PMID:24308808
Primitive reflexes in Parkinson's disease.
Vreeling, F. W.; Verhey, F. R.; Houx, P. J.; Jolles, J.
1993-01-01
A standardised protocol for the examination of 15 primitive reflexes in which the amplitude and the persistence were scored separately, was applied to 25 patients with Parkinson's disease and an equal number of healthy matched control subjects. Most reflexes were found considerably more often in the patients than in the control subjects, especially the snout, the glabellar tap, and its variant, the nasopalpebral reflex. Only the mouth open finger spread reflex was present more often in the co...
On Reflection : Is Reflexivity Necessarily Beneficial in Intercultural Education?
DEFF Research Database (Denmark)
Blasco, Maribel
2012-01-01
This article explores how the concept of reflexivity is used in intercultural education. Reflexivity is often presented as a key learning goal in acquiring intercultural competence (ICC). Yet, reflexivity can be defined in different ways, and take different forms across time and space, depending on the concepts of selfhood that prevail and how notions of difference are constructed. First, I discuss how the dominant usages of reflexivity in intercultural education reflect and reproduce a Cartesian view of the self that shapes how ICC is conceptualized and taught. I discuss three assumptions that this view produces: that the self is accessible and transcendable, that reflexivity is universal across space and time, and that the self can act as its own remedial change agent or ‘inner consultant.’ I argue that because reflexivity is understood in many different ways, attention to definition is crucial, both in designing learning objectives in intercultural education and in devising ways to attain them. Greater attention is also needed in intercultural education to the ways in which selfhood, and hence also reflexivity and constructions of difference, differ across space and time.
Angles and Polar Coordinates In Real Normed Spaces
Thu?rey, Volker
2009-01-01
We try to create a wise definition of 'angle spaces'. Based on an idea of Ivan Singer, we introduce a new concept of an angle in real Banach spaces, which generalizes the euclidean angle in Hilbert spaces. With this angle it is shown that in every two-dimensional subspace of a real Banach space we can describe elements uniquely by polar coordinates.
Homotopical stable ranks for Banach algebras
Nica, Bogdan
2009-01-01
The connected stable rank and the general stable rank are homotopy invariants for Banach algebras, whereas the Bass stable rank and the topological stable rank should be thought of as dimensional invariants. This paper studies the two homotopical stable ranks, viz. their general properties as well as specific examples and computations. The picture that emerges is that of a strong affinity between the homotopical stable ranks, and a marked contrast with the dimensional ones.
Emergence and Reflexive Downward
John Symons
2002-01-01
This paper responds to Jaegwon Kim's powerful objection to the very possibility of genuinely novel emergent properties Kim argue that the incoherence of reflexive downward causation means that the causal power of an emergent phenomenon is ultimately reducible to the causal powers of its constituents. I offer a a simple argument showing how to characterize emergent properties m terms of the effects of structural relations an the causal powers of that constituents.
Adductor T reflex abnormalities in patients with decreased patellar reflexes.
Tataroglu, Cengiz; Deneri, Ersin; Ozkul, Ayca; Sair, Ahmet; Yaycioglu, Soner
2009-08-01
The adductor reflex (AR) is a tendon reflex that has various features that differ from other tendon reflexes. This reflex was tested in different disorders presenting with diminished patellar reflexes such as diabetic lumbosacral radiculoplexus neuropathy (DLRPN), L2-L4 radiculopathy, and distal symmetric diabetic neuropathy (diabetic PNP). The AR and crossed-AR (elicited by tapping the contralateral patellar tendon) were recorded using concentric needle electrodes. Additionally, the patellar T reflex (vm-TR) and vastus medialis H reflex (vm-HR) were recorded using surface electrodes. AR was recorded in only one out of eight patients with DLRPN, but it was recorded in 21 out of 22 patients with L2-L4 radiculopathy (95.5%). Of these reflexes, only AR showed prolonged latency in the L2-L4 radiculopathy group. The latencies of AR, vm-TR, and vm-HR were prolonged in patients with diabetic PNP. We conclude that AR can be useful in the differential diagnosis of some lower motor neuron disorders that present with patellar reflex disturbance. Muscle Nerve 40: 264-270, 2009. PMID:19609916
Perceptual Rivalry: Reflexes Reveal the Gradual Nature of Visual Awareness
Naber, Marnix; Frässle, Stefan; Einhäuser, Wolfgang
2011-01-01
Rivalry is a common tool to probe visual awareness: a constant physical stimulus evokes multiple, distinct perceptual interpretations (“percepts”) that alternate over time. Percepts are typically described as mutually exclusive, suggesting that a discrete (all-or-none) process underlies changes in visual awareness. Here we follow two strategies to address whether rivalry is an all-or-none process: first, we introduce two reflexes as objective measures of rivalry, pupil dilation and optokinetic nystagmus (OKN); second, we use a continuous input device (analog joystick) to allow observers a gradual subjective report. We find that the “reflexes” reflect the percept rather than the physical stimulus. Both reflexes show a gradual dependence on the time relative to perceptual transitions. Similarly, observers' joystick deflections, which are highly correlated with the reflex measures, indicate gradual transitions. Physically simulating wave-like transitions between percepts suggest piece-meal rivalry (i.e., different regions of space belonging to distinct percepts) as one possible explanation for the gradual transitions. Furthermore, the reflexes show that dominance durations depend on whether or not the percept is actively reported. In addition, reflexes respond to transitions with shorter latencies than the subjective report and show an abundance of short dominance durations. This failure to report fast changes in dominance may result from limited access of introspection to rivalry dynamics. In sum, reflexes reveal that rivalry is a gradual process, rivalry's dynamics is modulated by the required action (response mode), and that rapid transitions in perceptual dominance can slip away from awareness. PMID:21677786
Supersets for the spectrum of elements in extended Banach algebras
Morteza Seddighin
1989-01-01
If A is a Banach Algebra with or without an identity, A can be always extended to a Banach algebra AÃ‚Â¯ with identity, where AÃ‚Â¯ is simply the direct sum of A and C, the algebra of complex numbers. In this note we find supersets for the spectrum of elements of AÃ‚Â¯.
Jóhannes Gísli Jónsson
2011-01-01
This paper argues that the simple reflexive pronoun sig is unambiguously a thematic argument in Icelandic. This is shown to be true not only of sig with naturally reflexive verbs but also of inherently reflexive sig. This view is mainly supported by two sets of facts: (i) that sig is impossible with verbs that fail to theta-mark their object (middles and anticausatives), and (ii) that case assignment works the same way for sig as for non- reflexive DP arguments. Potential counterarguments aga...
Measures on Banach Manifolds and Supersymmetric Quantum Field Theory
Weitsman, J
2005-01-01
We show how to construct measures on Banach manifolds associated to supersymmetric quantum field theories. We give three concrete examples of our construction. The first example is a family $\\mu_P^{s,t}$ of measures on a space of functions on the two-torus, parametrized by a polynomial $P$ (the Wess-Zumino-Landau-Ginzburg model). The second is a family $\\mu_\\cG^{s,t}$ of measures on a space $\\cG$ of maps from $\\P^1$ to a Lie group (the Wess-Zumino-Novikov-Witten model). Finally we study a family $\\mu_{M,G}^{s,t}$ of measures on the product of a space of connections on the trivial principal bundle with structure group $G$ on a three-dimensional manifold $M$ with a space of $\\fg$-valued three-forms on $M.$ We show that these measures are positive, and that the measures $\\mu_\\cG^{s,t}$ are Borel probability measures. As an application we show that formulas arising from expectations in the measures $\\mu_\\cG^{s,1}$ reproduce formulas discovered by Frenkel and Zhu in the theory of vertex operator algebras. We conje...
Primitive reflex profile. A pilot study.
Capute, A J; Accardo, P J; Vining, E P; Rubenstein, J E; Walcher, J R; Harryman, S; Ross, A
1978-09-01
Seven primitive reflexes used by physical and occupational therapists in evaluating children with cerebral palsy were each graded on a 0 to 4+ scale to constitute a Primitive Reflex Profile. The reflexes studied were the asymmetrical tonic neck reflex, the symmetrical tonic neck reflex, the tonic labyrinthine reflex, the positive support reflex, the derotational righting reflex, the Moro reflex, and the Galant reflex. The Primitive Reflex Profile was studied in 53 cerebral palsied patients to assess both the feasibility of its administration and its usefulness in discriminating functional levels of ambulation. The Primitive Reflex Profile was administered by at least two members of a team consisting of four pediatric developmentalists and two physical therapists. In using this instrument, the extreme functional groups were clearly defined and showed the expected overlap with the intermediate classification. PMID:684082
Gordji, M E
2006-01-01
Let $X$ be a left introverted subspace of dual of a Banach algebra. We study $Z_t(X^*),$ the topological center of Banach algebra $X^*$. We fined the topological center of $(X\\cA)^*$, when $\\cA$ has a bounded right approximate identity and $\\cA\\subseteq X^*.$ So we introduce a new notation of amenability for a dual Banach algebra $\\cal A$. A dual Banach algebra $\\cal A$ is weakly Connes-amenable if the first $weak^*-$continuous cohomology group of $\\cal A$ with coefficients in $\\cal A$ is zero; i.e., $H^1_{w^*}(\\cal A, \\cal A)=\\{o\\}$. We study the weak Connes-amenability of some dual Banach algebras.
Decompositions of Reflexive Modules
Goebel, Ruediger; Shelah, Saharon
2000-01-01
We continue [GbSh:568] (math.LO/0003164), proving a stronger result under the special continuum hypothesis (CH). The original question of Eklof and Mekler related to dual abelian groups. We want to find a particular example of a dual group, which will provide a negative answer to the question. In order to derive a stronger and also more general result we will concentrate on reflexive modules over countable principal ideal domains R. Following H.Bass, an R-module G is reflexi...
Reflex Sympathetic Dystrophy Syndrome
Directory of Open Access Journals (Sweden)
Annil Mahajan, Pawan Suri, Ghulam Hussain Bardi, J.B. Singh, Dheeraj Gandotra, Vijay Gupta
2004-07-01
Full Text Available Reflex Sympathetic Dystrophy (RSD or Complex Regional Pain Syndome Type-I (CRPS-I, adisease of unknown prevalance, complicates any minor trauma, stroke, myocardial infection, colle’sfracture, peripheral nerve injury and in one-fourth of cases without any precipitant factor. Anawareness of RSD and the injuries, illnesses and drugs that can provoke it is the first step to learnfor an early treatment and better outcome. Here we present a neglected case of RSD followingminor trauma who presented to us after 6-7 months of onset of disease. Delay in treatment resultedin partial recovery of the patient.
Hyers-Ulam-Rassias stability of Jordan homomorphisms on Banach algebras
Directory of Open Access Journals (Sweden)
Hirasawa Go
2005-01-01
Full Text Available We prove that a Jordan homomorphism from a Banach algebra into a semisimple commutative Banach algebra is a ring homomorphism. Using a signum effectively, we can give a simple proof of the Hyers-Ulam-Rassias stability of a Jordan homomorphism between Banach algebras. As a direct corollary, we show that to each approximate Jordan homomorphism from a Banach algebra into a semisimple commutative Banach algebra there corresponds a unique ring homomorphism near to .
Analytic semigroups of pseudodifferential operators on vector-valued Sobolev spaces
Barraza Martinez, Bienvenido; Denk, Robert; Hernandez Monzon, Jairo
2012-01-01
In this paper we study continuity and invertibility of pseudodifferential operators with non-regular Banach space valued symbols. The corresponding pseudodifferential operators generate analytic semigroups on the Sobolev spaces Wpk(Rn,E). Here E is an arbitrary Banach space. We also apply the theory to solve non-autonomous parabolic pseudodifferential equations in Sobolev spaces.
Motor functions: associated primitive reflex profiles.
Capute, A J; Shapiro, B K; Accardo, P J; Wachtel, R C; Ross, A; Palmer, F B
1982-10-01
The results of reflex/motor activity interactions in 177 normal infants are evaluated. The asymmetrical tonic neck reflex, tonic labyrinthine reflex-supine, and Moro reflexes were assessed for each child at birth and at intervals up to 12 months. Ages of rolling prone to supine, rolling supine to prone, and sitting alone were elicited from parents. The effects of the primitive reflexes on early motor activity were assessed, and statistically significant correlations were demonstrated between decreased reflex activity and the emergence of motor milestones. The distinctive association of reflex activity with motor function suggests the interaction of several reflexes (a primitive reflex profile) rather than the influence of isolated reflex activity. Such patterns support the hypothesis that decreasing primitive reflex activity is associated with the onset of volitional motor activity in normal infants. PMID:6183159
QCSP on partially reflexive forests
Martin, Barnaby
2011-01-01
We study the (non-uniform) quantified constraint satisfaction problem QCSP(H) as H ranges over partially reflexive forests. We obtain a complexity-theoretic dichotomy: QCSP(H) is either in NL or is NP-hard. The separating condition is related firstly to connectivity, and thereafter to accessibility from all vertices of H to connected reflexive subgraphs. In the case of partially reflexive paths, we give a refinement of our dichotomy: QCSP(H) is either in NL or is Pspace-complete.
Topological radicals, IV. Frattini theory for Banach Lie algebras
Kissin, Edward; Turovskii, Yurii
2012-01-01
The paper develops the theory of topological radicals of Banach Lie algebras and studies the structure of Banach Lie algebras with sufficiently many Lie subalgebras of finite codimensions -- the intersection of all these subalgebras is zero. It is shown that the intersections of certain families of Lie subalgebras (closed Lie subalgebras of finite codimension, closed Lie ideals of finite codimension, closed maximal Lie subalgebras of finite codimension, closed maximal Lie ideals of finite codimension) correspond to different preradicals, and that these preradicals generate the same radical, the Frattini radical. The main attention is given to structural properties of Frattini-semisimple Banach Lie algebras and, in particular, to a new infinite-dimensional phenomenon associated with the strong Frattini preradical introduced in this paper. A constructive description of Frattini-free Banach Lie algebras is obtained.
A Banach algebraic Approach to the Borsuk-Ulam Theorem
Taghavi, Ali
2011-01-01
Using methods from the theory of commutative graded Banach algebras, we obtain a generalization of the two dimensional Borsuk-Ulam theorem as follows: Let $\\phi:S^{2} \\rightarrow S^{2}$ be a homeomorphism of order n and $\\lambda\
Dentocardiac Reflex: an Allegedly New Subform of the Trigeminocardiac Reflex
Amr Abdulazim; Ashkan Rashad; Behnam Bohluli; Bernhard Schaller; Fatemeh Momen-Heravi; Pooyan Sadr-Eshkevari
2011-01-01
Trigeminocardiac reflex (TCR) is currently defined as a sudden bradycardia and decrease in mean arterial blood pressure by 20% during the manipulation of the branches of trigeminal nerve. TCR, especially during the last decade has been mostly studied in the course of neurosurgical procedures which are supposed to elicit the central subtype of TCR. Previously the well-known oculocardiac reflex was also considered as a subtype of TCR. Recently, surgeons dealing with the other branches of the fi...
Operators which factor through Banach lattices not containing c_0
Ghoussoub, Nassif; Johnson, William B.
1990-01-01
In this supplement to [GJ1], [GJ3], we give an intrinsic characterization of (bounded, linear) operators on Banach lattices which factor through Banach lattices not containing a copy of $c_0$ which complements the characterization of [GJ1], [GJ3] that an operator admits such a factorization if and only if it can be written as the product of two operators neither of which preserves a copy of $c_0$. The intrinsic characterization is that the restriction of the second adjoint ...
Annihilators in infinite-dimensional Grassmann-Banach algebras
International Nuclear Information System (INIS)
A family of infinite-dimensional Grassmann-Banach algebras over a complete normed field K is considered. It is shown that every element G of the family is an associative supercommutative Banach superalgebra over K: G double-bond G0 circle-plus G1 with zero annihilators G0perpendicular double-bond G1perpendicular double-bond(G1(?))perpendicular double-bond(0), k ? 2
Polynomial Bridgeland Stable Objects and Reflexive Sheaves
Lo, Jason
2011-01-01
On a smooth projective threefold, we show that there are only two isomorphism types for the moduli of stable objects with respect to Bayer's standard polynomial Bridgeland stability - the moduli of Gieseker-stable sheaves and the moduli of PT-stable objects - under the following assumptions: no two of the stability vectors are collinear, and the degree and rank of the objects are relatively prime. We also describe a close relation between the intersection of the moduli spaces of PT-stable and dual-PT-stable objects, and the moduli of reflexive sheaves.
Neufang, Matthias
2002-01-01
Let G be a locally compact group. Consider the Banach algebra L_1(G)^**, equipped with the first Arens multiplication, as well as the algebra LUC(G)^*, the dual of the space of bounded left uniformly continuous functions on G, whose product extends the convolution in the measure algebra M(G). We present (for the most interesting case of a non-compact group) completely different - in particular, direct - proofs and even obtain sharpened versions of the results, first proved b...
Dentocardiac Reflex: an Allegedly New Subform of the Trigeminocardiac Reflex
Directory of Open Access Journals (Sweden)
Amr Abdulazim
2011-05-01
Full Text Available Trigeminocardiac reflex (TCR is currently defined as a sudden bradycardia and decrease in mean arterial blood pressure by 20% during the manipulation of the branches of trigeminal nerve. TCR, especially during the last decade has been mostly studied in the course of neurosurgical procedures which are supposed to elicit the central subtype of TCR. Previously the well-known oculocardiac reflex was also considered as a subtype of TCR. Recently, surgeons dealing with the other branches of the fifth cranial nerve have become more interested in this reflex. Some noteworthy points have been published discussing new aspects of the trigeminocardiac reflex (TCR in simple oral surgical procedures. Arakeri et al. have reviewed the similarities and differences between TCR, vasovagal response (VVR, and syncope. They have also explained a new possible pathway for the reflex during the simple extraction of upper first molars. The present paper aims to briefly discuss these recently presented points. Although the discussed concepts are noteworthy and consistent our preliminary results of our yet to be published studies, it seemed timely for us to discuss some possible shortcomings that may affect the results of such assessments.
Operating characteristics of a magnetically insulated reflex ion diode
International Nuclear Information System (INIS)
Steady-state space charge limited-flow calculations have been carried out for an applied B/sub theta/ magnetically insulated reflexing ion diode. Reflex ion energy spectra characteristic of a thin foil cathode and of a transparent mesh have been used. A one-dimensional calculation shows higher ion current densities with a mesh cathode, and that the emission electron current density increases with the applied B/sub theta/ magnetic field. The ion current density is calculated to increase slightly with radius
On Sussmann theorem for orbits of sets of vector fields on Banach manifolds
Lathuille, Arnauld
2011-01-01
The purpose of this paper is to give some generalizations, in the context of Banach mani- folds, of Sussmann's results about the orbits of families of vector fields ([Su]). Essentially, we define the notion of "l1-orbits" for any family of vector fields on a Banach manifold, and we prove, under appropriate assumptions, that such an orbit is a weak Banach submanifold.
Lower bounds for homological dimensions of Banach algebras
International Nuclear Information System (INIS)
Let A be a commutative unital Banach algebra with infinite spectrum. Then by Helemskii's global dimension theorem the global homological dimension of A is strictly greater than one. This estimate has no analogue for abstract algebras or non-normable topological algebras. It is proved in the present paper that for every unital Banach algebra B the global homological dimensions and the homological bidimensions of the Banach algebras A widehat-otimes B and B (assuming certain restrictions on A) are related by A widehat-otimes B?2 + dg B and A widehat-otimes B?2 + db B. Thus, a partial extension of Helemskii's theorem to tensor products is obtained. Bibliography: 28 titles.
Albert Wilansky
1981-01-01
A Mazur space is a locally convex topological vector space X such that every fÃÂµXs is continuous where Xs is the set of sequentially continuous linear functionals on X; Xs is studied when X is of the form C(H), H a topological space, and when X is the weak * dual of a locally convex space. This leads to a new classification of compact T2 spaces H, those for which the weak * dual of C(H) is a Mazur space. An open question about Banach spaces with weak * sequentially compact dual ball is ...
TRANSIENT RELEASE REFLEXES IN CATONIC SCHIZOPHRENIA
Damodaran, Saji S.; Sinha, Vinod K.
1994-01-01
This case report describes the presence of grasp reflex and palmomental reflex as a state dependant phenomenon in a 23 year old patient with catatonic schizophrenia. A transitory disturbance of frontal lobe function is proposed as the probable mechanism. The need to study the release reflexes as an effort to delineate a neurological “sub group” of schizophrenia is suggested.
Educating the Reflexive Practitioner
Directory of Open Access Journals (Sweden)
Marc J. Neveu
2012-09-01
Full Text Available “I cannot teach anybody anything, I can only make them think.”SocratesIntroductionStudio as a model of education is distinct from many other professionaldisciplines and although it can be quite rewarding on many levels it mayalso be an extremely unconstructive endeavor.1 The amount of time spent in studio typically far outweighs that spent for other courses and often atthe expense of such other courses. The dedication that students bring tothe studio is remarkable, yet much of the time spent in studio is not alwaysproductive. Students often complain of not knowing what is expected ofthem and as a result much of the time is spent thinking about what they think the professor wants to see as opposed to working through theirprojects. In an alternate scenario, students are crushed by the workload, tasks, demands or expectations of their instructors. In either case, the work is almost invariably driven by the students’ own creativity and imagination; unlike law, medicine, business, or engineering for example, where the interpretation and inquiry into case studies and cadaversis much less based on the personal introspection than established traditions. This extremely personal nature of the architectural studio canmake reviews either a devastating or extremely empowering process. As seen from the perspective of the larger university community, the studio is simply not an efficient way of education. The faculty to student ratio, for example, is not in accordance with other undergraduate disciplines. But this ratio, as we all know can also be a real strength. The often hermeticnature of the studio offers latitude for students to develop theirwork in relatively safe surroundings. This environment, however, may also foster the cult of personality that develops around certain professorsthat harkens back to the very roots of education but can also lead to anentourage of disciples who have no incentive to inform the Emperor that he or she is no longer wearing any clothes.Notwithstanding such issues, I do believe the studio holds the potentialto be an empowering learning experience. The intention of this article is to question the mode of instruction in an architectural studio. I’ve structured the paper in three parts. First, I will briefly describe the findingsof the study made by the Carnegie Foundation for the Advancementof Teaching known as the Boyer Report.2 To develop and support the findings of the Boyer Report, I introduce the work of the educator Donald Schön. Though I see much merit in the Boyer Report, and Schön’sproposals, I argue that a more nuanced approach is required. I will recommend, therefore, in the second section of this paper that a meansof architectural education as based on the Socratic method may be amore productive approach. My reading of the Socratic method is basedprimarily on early Socratic dialogues and I will specifically use Charmidesto illustrate the issues that I believe are relevant to studio pedagogy.3 From my analysis of Charmides I will, in the third section of the essay,describe how the Socratic method is beneficial to studio pedagogy threeways: reflexive, non-propositional, and finally how Socrates’ approachmay indeed be practical. This last section will be illustrated with a studentproject. It is my conjecture that the Socratic method offers insight intocurrent discussions of educational theory, namely student-centered,project-based learning.
Reflexive aerostructures: increased vehicle survivability
Margraf, Thomas W.; Hemmelgarn, Christopher D.; Barnell, Thomas J.; Franklin, Mark A.
2007-04-01
Aerospace systems stand to benefit significantly from the advancement of reflexive aerostructure technologies for increased vehicle survivability. Cornerstone Research Group Inc. (CRG) is developing lightweight, healable composite systems for use as primary load-bearing aircraft components. The reflexive system is comprised of piezoelectric structural health monitoring systems, localized thermal activation systems, and lightweight, healable composite structures. The reflexive system is designed to mimic the involuntary human response to damage. Upon impact, the structural health monitoring system will identify the location and magnitude of the damage, sending a signal to a discrete thermal activation control system to resistively heat the shape memory polymer (SMP) matrix composite above activation temperature, resulting in localized shape recovery and healing of the damaged areas. CRG has demonstrated SMP composites that can recover 90 percent of flexural yield stress and modulus after postfailure healing. During the development, CRG has overcome issues of discrete activation, structural health monitoring integration, and healable resin systems. This paper will address the challenges associated with development of a reflexive aerostructure, including integration of structural health monitoring, discrete healing, and healable shape memory resin systems.
Almost Lie structures on an anchored Banach bundle
Cabau, Patrick
2011-01-01
Under appropriate assumptions, we generalize the concept of linear almost Poisson struc- tures, almost Lie algebroids, almost differentials in the framework of Banach anchored bundles and the relation between these objects. We then obtain an adapted formalism for mechanical systems which is illustrated by the evolutionary problem of the "Hilbert snake"
Banach matchboxes problem and a congruence for primes
Shevelev, Vladimir
2011-01-01
Using an identity arising in the known Banach probability problem on matchboxes, we prove an unexpected congruence for odd prime $p:$ for $1\\leq k\\leq \\frac{p-1}{2},\\enskip \\sum_{i=1}^{p-2k-1}2^{i-1}\\binom{k-1+i}{k}\\equiv 0\\pmod p.$
Trigeminocardiac reflexes: maxillary and mandibular variants of the oculocardiac reflex.
Lang, S; Lanigan, D T; van der Wal, M
1991-09-01
Three case reports are presented to illustrate the existence and importance of reflex bradycardic responses that can occur during maxillofacial surgical procedures. All three patients were healthy young adults undergoing operations which did not include any manipulation of orbital structures. After the patients had been anaesthetized for some time and were haemodynamically stable, profound bradycardia or ventricular asystole occurred suddenly in response to manipulations of the bony structures of the maxilla or mandible, or dissection of, or traction on, the attached soft tissue structures. The parasympathetic supply to the face is carried in the trigeminal nerve. Alternative afferent pathways must exist via the maxillary and/or mandibular divisions, in addition to the commonly reported pathway via the ophthalmic division of the trigeminal nerve in the classic oculocardiac reflex. The efferent arc involves the vagus, regardless of which branch of the trigeminal nerve transmits the afferent impulses. All patients undergoing maxillofacial procedures should be monitored carefully for reflex bradycardia and ventricular asystole. PMID:1914059
Integrating Reflexivity in Livelihoods Research
DEFF Research Database (Denmark)
Prowse, Martin
2010-01-01
Much poverty and development research is not explicit about its methodology or philosophical foundations. Based on the extended case method of Burawoy and the epistemological standpoint of critical realism, this paper discusses a methodological approach for reflexive inductive livelihoods research that overcomes the unproductive social science dualism of positivism and social constructivism. The approach is linked to a conceptual framework and a menu of research methods that can be sequenced and iterated in light of research questions.
Integrating Reflexivity in Livelihoods Research
Prowse, Martin
2010-01-01
Much poverty and development research is not explicit about its methodology or philosophical foundations. Based on the extended case method of Burawoy and the epistemological standpoint of critical realism, this paper discusses a methodological approach for reflexive inductive livelihoods research that overcomes the unproductive social science dualism of positivism and social constructivism. The approach is linked to a conceptual framework and a menu of research methods that can be sequenced ...
Geometry of Müntz spaces and related questions
Gurariy, Vladimir
2005-01-01
Starting point and motivation for this volume is the classical Muentz theorem which states that the space of all polynomials on the unit interval, whose exponents have too many gaps, is no longer dense in the space of all continuous functions. The resulting spaces of Muentz polynomials are largely unexplored as far as the Banach space geometry is concerned and deserve the attention that the authors arouse. They present the known theorems and prove new results concerning, for example, the isomorphic and isometric classification and the existence of bases in these spaces. Moreover they state many open problems. Although the viewpoint is that of the geometry of Banach spaces they only assume that the reader is familiar with basic functional analysis. In the first part of the book the Banach spaces notions are systematically introduced and are later on applied for Muentz spaces. They include the opening and inclination of subspaces, bases and bounded approximation properties and versions of universality.
Trigeminocardiac reflex in the Postanesthesia care unit.
Hemmer, Laura B; Afifi, Sherif; Koht, Antoun
2010-05-01
Bradycardia caused by the oculocardiac reflex is an anticipated occurrence during certain surgeries. The afferent pathway involves the trigeminal nerve's ophthalmic division. Reflex bradycardia from the trigeminocardiac reflex, via stimulation of maxillary or mandibular divisions of cranial nerve V, although less well known, has also been reported intraoperatively. Unstable bradycardia associated with stimulation of the mandibular division of cranial nerve V during trigeminal neuralgia pain episodes in the Postanesthesia Care Unit is presented. PMID:20400008
Arakeri’s Reflex: an Alternative Pathway for Dento-Cardiac Reflex Mediated Syncope
Veena Arali; Shailaja Reddy; Raghuram, C. G.; Gururaj Arakeri
2010-01-01
Introduction: Dentocardiac reflex, a variant of trigeminocardiac reflex elicited specifically during tooth extraction procedures in den-tal/maxillofacial surgery and is believed to cause syncope with an afferent link mediated by posterior superior alveolar nerve. Another variant of trigeminocardiac reflex which is also of interest to the oral and maxillofacial surgeon is oculocardiac reflex which can be triggered by direct or indirect manipulation of eye globe or muscles around it.The hypothe...
Stability of stationary and periodic solutions equations in Banach space
Directory of Open Access Journals (Sweden)
A. Ya. Dorogovtsev
1997-01-01
Full Text Available Linear difference and differential equations with operator coefficients and random stationary (periodic input are considered. Conditions are presented for the mean stability of stationary (periodic solutions under small perturbation of the coefficients.
SOME LYAPUNOV TYPE POSITIVE OPERATORS ON ORDERED BANACH SPACES
Vasile Dragan; Toader Morozan; Viorica Ungureanu
2013-01-01
In this paper we investigate several properties of Lyapunov type operators occurring in connection with the characterization of exponential stability in mean square of systems of linear It^o differential equations perturbed by a Markov process with an innite countable number of states. A criterion for exponential stability of linear differential equations defined by a Lyapunov operator is derived under the assumption of property of detetability adequately defined for this type of operator val...
Sharp form of the Sobolev trace theorems. [Proof of trace theorems for Besov spaces
Energy Technology Data Exchange (ETDEWEB)
Scott, R.
1977-05-01
Trace theorems for Besov spaces are proved by use of piecewise polynomial approximation theory and the K-method of interpolating Banach spaces. These theorems are limiting cases of standard embedding results.
Representation of by vector-valued function spaces
Fourie, Jan H.
2007-08-01
In this paper we use results from the theory of tensor products of Banach spaces to establish the isometry of the space of so-called strongly p-integrable functions in a Banach space X to the space of integral X-valued operators on Lp([mu]) and the complete projective tensor product of Lp([mu]) with an arbitrary Banach space X. Although there are similar results in recent papers (for instance in [Q. Bu, P.K. Lin, Radon-Nikodym property for the projective tensor product of Kothe function spaces, J. Math. Anal. Appl. 293 (2004) 149-159] and [J. Diestel, J.H. Fourie, J. Swart, The projective tensor product II: The Radon-Nikodym property, Rev. R. Acad. Cienc. Ser. A Mat. 100 (2006) 75-100]), our contribution in the present paper is to remove all restrictions attached to the Banach space X. Through similar techniques, the result is then also considered in the context of the complete projective tensor product of a Banach lattice X (satisfying some conditions) with an arbitrary Banach space Y.
Lectures given at the Banach Center and C.I.M.E. Joint Summer School
Lachowicz, Miros?aw
2008-01-01
The aim of this volume that presents Lectures given at a joint CIME and Banach Center Summer School, is to offer a broad presentation of a class of updated methods providing a mathematical framework for the development of a hierarchy of models of complex systems in the natural sciences, with a special attention to Biology and Medicine. Mastering complexity implies sharing different tools requiring much higher level of communication between different mathematical and scientific schools, for solving classes of problems of the same nature. Today more than ever, one of the most important challenges derives from the need to bridge parts of a system evolving at different time and space scales, especially with respect to computational affordability. As a result the content has a rather general character; the main role is played by stochastic processes, positive semigroups, asymptotic analysis, kinetic theory, continuum theory and game theory.
Operators which factor through Banach lattices not containing c_0
Ghoussoub, N; Ghoussoub, Nassif; Johnson, William B.
1992-01-01
In this supplement to [GJ1], [GJ3], we give an intrinsic characterization of (bounded, linear) operators on Banach lattices which factor through Banach lattices not containing a copy of $c_0$ which complements the characterization of [GJ1], [GJ3] that an operator admits such a factorization if and only if it can be written as the product of two operators neither of which preserves a copy of $c_0$. The intrinsic characterization is that the restriction of the second adjoint of the operator to the ideal generated by the lattice in its bidual does not preserve a copy of $c_0$. This property of an operator was introduced by C. Niculescu [N2] under the name ``strong type B".
The Dynamics of the Stapedial Acoustic Reflex.
Moss, Sherrin Mary
Available from UMI in association with The British Library. This thesis aims to separate the neural and muscular components of the stapedial acoustic reflex, both anatomically and physiologically. It aims to present an hypothesis to account for the differences between ipsilateral and contralateral reflex characteristics which have so far been unexplained, and achieve a greater understanding of the mechanisms underlying the reflex dynamics. A technique enabling faithful reproduction of the time course of the reflex is used throughout the experimental work. The technique measures tympanic membrane displacement as a result of reflex stapedius muscle contraction. The recorded response can be directly related to the mechanics of the middle ear and stapedius muscle contraction. Some development of the technique is undertaken by the author. A model of the reflex neural arc and stapedius muscle dynamics is evolved that is based upon a second order system. The model is unique in that it includes a latency in the ipsilateral negative feedback loop. Oscillations commonly observed on reflex responses are seen to be produced because of the inclusion of a latency in the feedback loop. The model demonstrates and explains the complex relationships between neural and muscle dynamic parameters observed in the experimental work. This more comprehensive understanding of the interaction between the stapedius dynamics and the neural arc of the reflex would not usually have been possible using human subjects, coupled with a non-invasive measurement technique. Evidence from the experimental work revealed the ipsilateral reflex to have, on average, a 5 dB lower threshold than the contralateral reflex. The oscillatory charcteristics, and the steady state response, of the contralateral reflex are also seen to be significantly different from those of the ipsilateral reflex. An hypothesis to account for the experimental observations is proposed. It is propounded that chemical neurotransmitters, and their effect upon the contralateral reflex arc from the site of the superior olivary complex to the motoneurones innervating the stapedius, account for the difference between the contralateral and ipsilateral reflex thresholds and dynamic characteristics. In the past two years the measurement technique used for the experimental work has developed from an audiological to a neurological diagnostic tool. This has enabled the results from the study to be applied in the field for valuable biomechanical and neurological explanations of the reflex response. (Abstract shortened by UMI.).
Characterizing Hilbert spaces using Fourier transform over the field of p-adic numbers
Radyna, Yauhen; Sidorik, Anna
2008-01-01
We characterize Hilbert spaces in the class of all Banach spaces using Fourier transform of vector-valued functions over the field $Q_p$ of $p$-adic numbers. Precisely, Banach space $X$ is isomorphic to a Hilbert one if and only if Fourier transform $F: L_2(Q_p,X)\\to L_2(Q_p,X)$ in space of functions, which are square-integrable in Bochner sense and take value in $X$, is a bounded operator.
Regular norm and the operator semi-norm on a non-unital Banach Algebra
Orenstein, Adam
2014-01-01
We show that if $\\mathfrak{A}$ is a Banach Algebra with norm $\\|\\cdot\\|$ and with no left unit, then $\\|\\cdot\\|$ is regular on $\\mathfrak{A}$ if and only if $\\|\\cdot\\|_{op}$ is a norm $\\mathfrak{A}\\oplus\\mathbb{C}$ is a Banach Algebra with respect to $\\|\\cdot\\|_{op}$.
Cutaneous reflex modulation and self-induced reflex attenuation in cerebellar patients.
Hoogkamer, Wouter; Van Calenbergh, Frank; Swinnen, Stephan P; Duysens, Jacques
2015-02-01
Modulation of cutaneous reflexes is important in the neural control of walking, yet knowledge about underlying neural pathways is still incomplete. Recent studies have suggested that the cerebellum is involved. Here we evaluated the possible roles of the cerebellum in cutaneous reflex modulation and in attenuation of self-induced reflexes. First we checked whether leg muscle activity during walking was similar in patients with focal cerebellar lesions and in healthy control subjects. We then recorded cutaneous reflex activity in leg muscles during walking. Additionally, we compared reflexes after standard (computer triggered) stimuli with reflexes after self-induced stimuli for both groups. Biceps femoris and gastrocnemius medialis muscle activity was increased in the patient group compared with the control subjects, suggesting a coactivation strategy to reduce instability of gait. Cutaneous reflex modulation was similar between healthy control subjects and cerebellar patients, but the latter appeared less able to attenuate reflexes to self-induced stimuli. This suggests that the cerebellum is not primarily involved in cutaneous reflex modulation but that it could act in attenuation of self-induced reflex responses. The latter role in locomotion would be consistent with the common view that the cerebellum predicts sensory consequences of movement. PMID:25392164
Astronomical Data Reduction Workflows with Reflex
Ballester, P.; Bramich, D.; Forchi, V.; Freudling, W.; Garcia-Dabó, C. E.; klein Gebbinck, M.; Modigliani, A.; Moehler, S.; Romaniello, M.
2014-05-01
Reflex (http://www.eso.org/reflex) is an environment that provides an easy and flexible way to reduce VLT/VLTI science data using the ESO. Its top-level functionalities are: (1) Reflex allows to graphically specify the sequence in which the data reduction steps are executed, including conditional stops, loops and conditional branches, (2) Reflex makes it easy to inspect the intermediate and final data products and to repeat selected processing steps to optimize the data reduction, (3) the data organization necessary to reduce the data is built into the system and is fully automatic, (4) advanced users can plug-in their own Python or IDL modules and steps into the data reduction sequence, and (5) Reflex supports the development of data reduction workflows based on the ESO Common Pipeline Library. Reflex is based on the concept of a scientific workflow, whereby the data reduction cascade is rendered graphically and data seamlessly flow from one processing step to the next. It is distributed with a number of complete test datasets so that users can immediately start experimenting and familiarize themselves with the system (http://www.eso.org/pipelines). In this demo, we present the latest version of Reflex and its applications for astronomical data reduction processes.
Scientific Electronic Library Online (English)
Mehdi, Dehghan; Masoud, Hajarian.
Full Text Available SciELO Brazil | Language: English Abstract in english An n × n real matrix P is said to be a generalized reflection matrix if P T = P and P² = I (where P T is the transpose of P). A matrix A ? Rn×n is said to be a reflexive (anti-reflexive) matrix with respect to the generalized reflection matrix P if A = P A P (A = - P A P). The reflexive and anti-ref [...] lexive matrices have wide applications in many fields. In this article, two iterative algorithms are proposed to solve the coupled matrix equations { A1 XB1 + C1X T D1 = M1. A2 XB2 + C2X T D2 = M2. over reflexive and anti-reflexive matrices, respectively. We prove that the first (second) algorithm converges to the reflexive (anti-reflexive) solution of the coupled matrix equations for any initial reflexive (anti-reflexive) matrix. Finally two numerical examples are used to illustrate the efficiency of the proposed algorithms. Mathematical subject classification: 15A06, 15A24, 65F15, 65F20.
Interpolation theorems for Block-Lorentz spaces.
Czech Academy of Sciences Publication Activity Database
Gogatishvili, Amiran; Moriton, S.; Niwa, M.; Sobukawa, T.
Yokohama : Yokohama Publishers, 2004, s. 215-223. [International Symposium on Banach and Function Spaces. Kitakyushu (JP), 02.10.2003-04.10.2003] Institutional research plan: CEZ:AV0Z1019905 Keywords : weighted Lorentz spaces * real interpolation * block-Lorentz spaces Subject RIV: BA - General Mathematics
A testbed for autonomous reflexive grasping
Kemme, David A.; McDonnell, John R.
1993-03-01
This work describes the development of a testbed which combines a subsumption architecture approach with neural network processing of tactile information in a reflexive behavior feasibility study. An overview of the tactile sensor, the neural network processor, and subsumption architecture is provided along with a plan for integrating these components into a single system. By incorporating local (reflexive) processing capabilities within a robot gripper, an additional layer of control is attained without an increased computing burden being placed on the system controller.
Reflexivity in Teams: A Measure and Correlates
Schippers, M. C.; Hartog, D. N. Den; Koopman, P. L.
2005-01-01
Reflexivity -the extent to which teams reflect upon and modify their functioning- has been identified as a possible key factor in the effectiveness of work teams. The aim of the present study was to develop a questionnaire to measure (aspects of) reflexivity, with a focus on team reflection. The questionnaire was tested in two different samples, namely a first sample of 59 teams from fourteen different organizations (Study 1) and a confirmation sample of 59 school management teams (Study 2). ...
Adductor T and H reflexes in humans.
Ertekin, Cumhur; Bademkiran, Fikret; Tataroglu, Cengiz; Aydogdu, Ibrahim; Karapinars, Nevin
2006-11-01
In the belief that changes in the adductor reflex (AR) may be helpful in evaluating lumbar root and plexus lesions, expression of the AR was studied in 43 healthy human subjects. ARs elicited with an electronic reflex hammer were recorded from the inner side of the proximal thigh using needle and surface electrodes, and patellar reflexes (PRs) were recorded simultaneously. These reflexes were obtained by tapping the ipsilateral medial aspect of the knee, the contralateral patellar tendon, the ipsilateral and contralateral anterior superior iliac spines, and the Achilles tendon. The H reflex of the obturator nerve was also evaluated in 17 cases. ARs were evoked consistently by tapping the ipsilateral medial aspect of the knee and by contralateral patellar tap, and by tapping ipsilateral and contralateral anterior superior iliac spines when a needle recording electrode was used. Sometimes an Achilles tendon tap also elicited the AR ipsilaterally. By contrast, the PR could only be elicited by a tap to the ipsilateral patellar tendon. ARs have somewhat different features than other well-known tendon reflexes such as the PR and are recorded consistently when a needle electrode is used, being elicited from both distal and proximal areas of the legs by tapping the Achilles tendon or anterior superior iliac spines unilaterally or bilaterally. Their role in evaluating lumbar root disease and monitoring adductor spasticity merits investigation. PMID:16941659
[The oculocardiac reflex during vitrectomy under neuroleptanalgesia].
Dornberger, I; Quast, D; Velhagen, K H; Bellach, J; Guckler, A
1991-01-01
Oculocardiac reflex (OCR) is a frequently occurring complication in eye operations. It is a trigemino-vagal reflex characterised by the clinical occurrence of bradycardia and other cardiac rhythm disturbances following manipulations on the eye and its surroundings especially after traction of the external eye muscles. In this paper based on an analysis of 402 anaesthesia records, a bradycardia frequency (f = less than 60/min) of 31.8% was noted while other rhythm disturbances occurred in 5.7%. Predisposition facts were identified as age over 50, hypertension and cardiac diseases requiring medication with cardiac drugs. The frequency of OCR is considerably lowered by diabetes mellitus. Examination of 159 traction measurements made at the lateral rectus muscle revealed that the first manipulation made at the rectus bulbi superior muscle resulted in a statistically significantly stronger reflex activity than at the other muscles. In a further series of investigations in which rectus bulbi superior muscle was tested last, this muscle again showed the biggest frequency deviation. Only determination of the percentage heart rate decrease is suitable for characterising reflex activity. The frequency of the reflex occurring in our study was 71.7%, the result being reduced by the high proportion of diabetics, who are relatively reflex insensitive. PMID:2054038
Hypercyclic operators on topological vector spaces
Shkarin, Stanislav
2010-01-01
Bonet, Frerick, Peris and Wengenroth constructed a hypercyclic operator on the locally convex direct sum of countably many copies of the Banach space $\\ell_1$. We extend this result. In particular, we show that there is a hypercyclic operator on the locally convex direct sum of a sequence $\\{X_n\\}_{n\\in\\N}$ of Fr\\'echet spaces if and only if each $X_n$ is separable and there are infinitely many $n\\in\\N$ for which $X_n$ is infinite dimensional. Moreover, we characterize inductive limits of sequences of separable Banach spaces which support a hypercyclic operator.
Somatosensory evoked potential of the stretch-reflex (T-reflex).
Ganchev, G N; Yankov, E
1979-01-01
Averaging of EEG recorded monopolarly from C3, contralateral to the activated limb, in the stretch reflex shows the presence of somatosensory evoked potential (SSEP) with characteristic shape: four constant waves--P29, N84, P202 and N294, and four inconstant waves--N31, P74, P99 and N123. Comparison of this SSEP with the SSEP in children, evoked in the stretch reflex, shows shorter latencies of the waves in adults. On the basis of data from the different series of experiments, it is assumed that kinesthetic signalization plays a dominant role in the genesis of SSEP of the T-reflex. Studies have shown that SSEP of the T-reflex is succeptible to habituation upon long repetition of the stretch reflex. PMID:543413
Reflexivity of the automorphism and isometry groups of the suspension of $B(H)$
Molnar, Lajos; Gyory, M.
1997-01-01
The aim of this paper is to show that the automorphism and isometry groups of the suspension of $B(H)$, $H$ being a separable infinite dimensional Hilbert space, are algebraically reflexive. This means that every local automorphism, respectively local surjective isometry of $C_0(\\mathbb R)\\otimes B(H)$ is an automorphism, respectively a surjective isometry.
Mobilizing "Implicit Activisms" in Schools through Practices of Critical Emotional Reflexivity
Zembylas, Michalinos
2013-01-01
This paper discusses the role of emotions in mobilizing implicit activisms--that is, small-scale, personal, and modest activisms--in schools. For this purpose, the discussion evokes the notion of critical emotional reflexivity to illuminate how creating spaces for critical reflection on emotions may contribute to making implicit activisms more…
Isometries of a function space
Directory of Open Access Journals (Sweden)
U. D. Vyas
1987-09-01
Full Text Available It is proved here that an isometry on the subset of all positive functions of L1Ã¢Â‹Â‚Lp(Ã¢Â„Â can be characterized by means of a function h together with a Borel measurable mapping ÃÂ• of Ã¢Â„Â, thus generalizing the Banach-Lamparti theorem of Lp spaces.
Determining elements in Banach algebras through spectral properties
Brešar, M
2012-01-01
Let $A$ be a Banach algebra. By $\\sigma(x)$ and $r(x)$ we denote the spectrum and the spectral radius of $x\\in A$, respectively. We consider the relationship between elements $a,b\\in A$ that satisfy one of the following two conditions: (1) $\\sigma(ax) = \\sigma(bx)$ for all $x\\in A$, (2) $r(ax) \\le r(bx)$ for all $x\\in A$. In particular we show that (1) implies $a=b$ if $A$ is a $C^*$-algebra, and (2) implies $a\\in \\mathbb C b$ if $A$ is a prime $C^*$-algebra. As an application of the results concerning the conditions (1) and (2) we obtain some spectral characterizations of multiplicative maps.
Reflexive structures an introduction to computability theory
Sanchis, Luis E
1988-01-01
Reflexive Structures: An Introduction to Computability Theory is concerned with the foundations of the theory of recursive functions. The approach taken presents the fundamental structures in a fairly general setting, but avoiding the introduction of abstract axiomatic domains. Natural numbers and numerical functions are considered exclusively, which results in a concrete theory conceptually organized around Church's thesis. The book develops the important structures in recursive function theory: closure properties, reflexivity, enumeration, and hyperenumeration. Of particular interest is the treatment of recursion, which is considered from two different points of view: via the minimal fixed point theory of continuous transformations, and via the well known stack algorithm. Reflexive Structures is intended as an introduction to the general theory of computability. It can be used as a text or reference in senior undergraduate and first year graduate level classes in computer science or mathematics.
An asymmetrical tonic neck reflex rating scale.
Parmenter, C L
1983-07-01
Although the asymmetrical tonic neck reflex (ATNR) is commonly used as one clinical assessment when evaluating children with suspected sensory integration deficits, maturational lags, or behavioral dysfunctions, observations are limited on the degree of this reflex in normal children at different age levels. A quantitative rating scale that indicates the degree of integration of the ATNR in normal first and third grade children is presented for purposes of comparison with the "suspect" child. A procedure for testing this reflex is described using the quadrupedal position, four sequences of lateral head rotation, and a rating scale consisting of four components. Using this ATNR rating scale, scores can be derived that could serve as a guide in determining whether the residual ATNR is comparable to that of normal subjects of the same age. PMID:6614125
Reflex and non-reflex torque responses to stretch of the human knee extensors.
Mrachacz-Kersting, N; Sinkjaer, T
2003-07-01
Reflex responses to unexpected stretches are well documented for selected muscles in both animal and human. Moreover, investigations of their possible functional significance have revealed that stretch reflexes can contribute substantially to the overall stiffness of a joint. In the lower extremity only the muscles spanning the human ankle joint have been investigated in the past. This study implemented a unique hydraulic actuator to study the contributions of the knee extensor stretch reflex to the overall knee joint torque. The quadriceps muscles were stretched at various background torques, produced either voluntarily or by electrical stimulation, and thus the purely reflex mediated torque could be calculated. The stretch had a velocity of 67 degrees /s and an amplitude of 20 degrees. A reflex response as measured by electromyography (EMG) was observed in all knee extensors at latencies of 26 - 36 ms. Both phasic and tonic EMG stretch responses increased with increasing background torques. Lines of best fit produced correlation coefficients of 0.59 - 0.78. This study is the first to examine the reflex contribution of the knee extensors to the total torque at background torques of 0 - 90% MVC. The contribution of the reflex mediated torque is initially low and peaked at background torques of 20 - 40% MVC. In terms of the total torque the reflex contributed 16 - 52% across all levels of background torque. It is concluded that during medium background torque levels such as those obtained during walking, the stretch reflex of the quadriceps muscle group contributes substantially to the total torque around the knee joint. PMID:12707748
Some properties of space of compact operators
Randrianantoanina, Narcisse
1994-01-01
Let $X$ be a separable Banach space, $Y$ be a Banach space and $\\Lambda$ be a subset of the dual group of a given compact metrizable abelian group. We prove that if $X^*$ and $Y$ have the type I-$\\Lambda$-RNP (resp. type II-$\\Lambda$-RNP) then $K(X,Y)$ has the type I-$\\Lambda$-RNP (resp. type II-$\\Lambda$-RNP) provided $L(X,Y)=K(X,Y)$. Some corollaries are then presented as well as results conserning the separability assumption on $X$. Similar results for the NearRNP and the...
Polarized neutron reflectometer 'Reflex-P'
Korneev, D A; Yaradajkin, S P
2002-01-01
About 10 years ago the idea of a new spectrometer 'Reflex' at the IBR-2 reactor was formulated. According to the initial idea, the spectrometer was projected as a combination of two reflectometers. One of them is the spectrometer with polarized neutrons and another one with nonpolarized neutrons. At present half of the project has been executed. On the 9th beam of the IBR-2 reactor the polarized branch of the spectrometer 'Reflex-P' is successfully working. This paper is devoted to the description of main parameters of this spectrometer and development perspectives.
Computer modeling of a spinal reflex circuit
Scientific Electronic Library Online (English)
Bruno L., Dalcin; Frederico Alan, Cruz; Célia Martins, Cortez; Emmanuel P. L., Passos.
2005-12-01
Full Text Available We used a set of properties of the interactions among the spinal neurons in order to develop a computer model for a spinal reflex circuit. The model equations take into account the synaptic characteristics of the somatodendritic membrane of neurons in a morphofunctional unity of the spinal reflex ac [...] tivity. This model is based on the idea that the responses of spinal alpha-motoneurons to a sensorial stimulation can be modulated by the serial activation of a motor command chain. We developed a Fortran program for simulating a physiological situation. The results are discussed in terms of available experimental data for the motoneuron firing rate.
Reflex control for safe autonomous robot operation
International Nuclear Information System (INIS)
This paper describes the design of an autonomous, sonar-based world mapping system for collision prevention in robotic systems. Obstacle detection and mapping is performed as a task that competes with higher-level tasks for the robot's attention. All tasks are integrated within a hierarchy, organized and co-ordinated by schemes analogous to biological reflexes and fixed action patterns. It is illustrated how the existence of low-level reflex behaviours can enhance the survivability and autonomy of complex systems and simplify the design of complex higher-level controls like our autonomous sonar-based world mapping system
Monitoring of head injury by myotatic reflex evaluation
Cozens, J.; Miller, S.; Chambers, I.; Mendelow, A.
2000-01-01
OBJECTIVES—(1) To establish the feasibility of myotatic reflex measurement in patients with head injury. (2) To test the hypothesis that cerebral dysfunction after head injury causes myotatic reflex abnormalities through disordered descending control. These objectives arise from a proposal to use reflex measurements in monitoring patients with head injury.?METHODS—The phasic stretch reflex of biceps brachii was elicited by a servo-positioned tendon hammer. Antago...
Is Palmomental Reflex Actually A Part of Feeding Behavior?
Ugurel, Burcu; Oztura, Ibrahim; Sener, Ufuk; Senocak, Ozlem; Hurel, Dilek; Yener, Gorsev; Ertekin, Cumhur
2009-01-01
Purpose and hypothesis: Palmomental reflex is considered to be a primitive reflex and related to pathologic processes. The reflex can be obtained from every individual by electrophysiologic measures. There have been no reports concerning submental, orbicularis oris and masseter muscle reflex responses provoked by median nerve stimulation in healthy elderly individuals and patients with dementia up to now.Method: In the present study the median nerve was stimulated below the pain threshold and...
Human investigations into the exercise pressor reflex
DEFF Research Database (Denmark)
Secher, Niels H; Amann, Markus
2012-01-01
During exercise, neural input from skeletal muscles reflexly maintains or elevates blood pressure (BP) despite a maybe fivefold increase in vascular conductance. This exercise pressor reflex is illustrated by similar heart rate (HR) and BP responses to electrically induced and voluntary exercise. The importance of the exercise pressor reflex for tight cardiovascular regulation during dynamic exercise is supported by studies using pharmacological blockade of lower limb muscle afferent nerves. These experiments show attenuation of the increase in BP and cardiac output when exercise is performed with attenuated neural feedback. Additionally, there is no BP response to electrically induced exercise with paralysing epidural anaesthesia or when similar exercise is evoked in paraplegic patients. Furthermore, BP decreases when electrically induced exercise is carried out in tetraplegic patients. The lack of an increase in BP during exercise with paralysed legs manifests, although electrical stimulation of muscles enhances lactate release and reduces muscle glycogen. Thus, the exercise pressor reflex enhances sympathetic activity and maintains perfusion pressure by restraining abdominal blood flow, while brain, skin and muscle blood flow may also become affected because the reflex 'resets' arterial baroreceptor modulation of vascular conductance, making BP the primarily regulated cardiovascular variable during exercise.
Atropine treatment of reflex anoxic seizures.
Mcwilliam, R. C.; Stephenson, J. B.
1984-01-01
In 7 children with unusually severe or frequent reflex anoxic seizures atropine treatment, which was well tolerated, reduced seizure frequency by a mean value of 98%. Treatment withdrawal (five patients) was followed by an increase in seizure frequency and reintroduction (three patients) by restoration of control.
Reflectivity, Reflexivity and Situated Reflective Practice
Malthouse, Richard; Roffey-Barentsen, Jodi; Watts, Mike
2014-01-01
This paper describes an aspect of reflective practice referred to as situated reflective practice. The overarching theory is derived from social theories of structuration and reflexivity. In particular, from Giddens' theory of structuration, which sees social life as an interplay of agency and structure. Discussion of the research reported…
Isoperimetric inequalities of euclidean type in metric spaces
Wenger, Stefan
2003-01-01
In this paper we prove an isoperimetric inequality of euclidean type for complete metric spaces admitting a cone-type inequality. These include all Banach spaces and all complete, simply-connected metric spaces of non-positive curvature in the sense of Alexandrov or, more generally, of Busemann. The main theorem generalizes results of Gromov and Ambrosio-Kirchheim.
Managing Normative Criteria in Action Research : A reflexive analysis
DEFF Research Database (Denmark)
Boulus-RØdje, Nina
2015-01-01
A much revisited question within the field of Information Systems is how research- ers can intervene in the context of large-scale, complex and heterogeneous information in- frastructures, while ensuring impact on field settings. To explore this question, I draw upon my interventions and fieldwork experiences from an action research project in a healthcare infrastructural setting. I use these experiences as a basis for appraising the normative crite- ria for rigor and relevance that are enacted in IS action research literature. I argue that while these criteria originally had important contributions, there are also weaknesses with norma- tive approaches. Specifically, these norms of action research leave relatively little space for understanding and managing emerging empirical uncertainties. These norms are important because they have implications not only on how we conduct action research in practice, but also on how we share research experiences, document and report research processes, and on how we use this literature for teaching and training purposes. Therefore, we need meth- odological perspectives more adequate to the varied experiences of empirical IS research. I propose replacing the normative frameworks found in some IS action research literature with a reflexive framework that encourages researchers to investigate critically how their methods are enacted and practiced in the field. The contribution of this paper lies in pro- viding a reflexive analysis of the situated and emergent challenges encountered when han- dling action researcher’s dual agenda of combining academic and practical contribution.
Reflexive polytopes of higher index and the number 12
Kasprzyk, Alexander M
2011-01-01
We introduce reflexive polytopes of index l as a natural generalisation of the notion of a reflexive polytope of index 1. These l-reflexive polytopes also appear as dual pairs. In dimension two we show that they arise from reflexive polygons via a change of the underlying lattice. This allows us to efficiently classify all isomorphism classes of l-reflexive polygons up to index 200. As another application, we show that any reflexive polygon of arbitrary index satisfies the famous "number 12" property. This is a new, infinite class of lattice polygons possessing this property, and extends the previously known sixteen instances. The number 12 property also holds more generally for l-reflexive non-convex or self-intersecting polygonal loops. We conclude by discussing higher-dimensional examples and open questions.
Feminist Politics as Reflexive Citizenship
Directory of Open Access Journals (Sweden)
Nikos Katrivesis
2008-11-01
Full Text Available This article examines the potential feminist contribution to a radically renovated citizenship, according to which we all ought to undertake our responsibilities towards family, society and world. This contribution mainly consists in the critical transgression of the traditional dualism between private and public space, which arises from the politicization of everyday experience and results to the emergence of an essentially participial civil society.
Reflex-diode high-power microwave source on Aurora
Huttlin, George A.; Bushell, Michael S.; Conrad, D. B.; Davis, David P.; Ebersole, K. L.; Judy, Daniel C.; Lezcano, P. A.; Litz, Marc S.; Pereira, Nino R.; Ruth, Brian G.; Weidenheimer, Douglas M.; Agee, Forrest J.
1990-04-01
Work begun in 1986 is continuing on the reflex-diode oscillator mounted on one of the Aurora 10-MV 22- ci pulsers. The most recent work extracted microwaves radially into six rectangular WR-975 waveguides at the virtual cathode and into two additional arms a few meters downstream. Two of the waveguides were open-ended and radiated into an anechoic chamber. Diagnostics for radially extracted microwave energy included directional couplers card calorimeters and free-field sensors. The peak output is ''-50 3 per arm for the frequencies below 1. 0 (3Hz. Parameter variations have included the anode/cathode spacing and the positioning of a second anode foil. Dosimetry and electric field measurements were made to study beani dynamics in the drift region. Thus far the measurements suggest that our virtual cathode is weak. 1.
Stick balancing with reflex delay in case of parametric forcing
Insperger, Tamas
2011-04-01
The effect of parametric forcing on a PD control of an inverted pendulum is analyzed in the presence of feedback delay. The stability of the time-periodic and time-delayed system is determined numerically using the first-order semi-discretization method in the 5-dimensional parameter space of the pendulum's length, the forcing frequency, the forcing amplitude, the proportional and the differential gains. It is shown that the critical length of the pendulum (that can just be balanced against the time-delay) can significantly be decreased by parametric forcing even if the maximum forcing acceleration is limited. The numerical analysis showed that the critical stick length about 30 cm corresponding to the unforced system with reflex delay 0.1 s can be decreased to 18 cm with keeping maximum acceleration below the gravitational acceleration.
The spinal reflex cannot be perceptually separated from voluntary movements.
Ghosh, Arko; Haggard, Patrick
2014-01-01
Both voluntary and involuntary movements activate sensors in the muscles, skin, tendon and joints. As limb movement can result from a mixture of spinal reflexes and voluntary motor commands, the cortical centres underlying conscious proprioception might either aggregate or separate the sensory inputs generated by voluntary movements from those generated by involuntary movements such as spinal reflexes. We addressed whether healthy volunteers could perceive the contribution of a spinal reflex during movements that combined both reflexive and voluntary contributions. Volunteers reported the reflexive contribution in leg movements that were partly driven by the knee-jerk reflex induced by a patellar tendon tap and partly by voluntary motor control. In one condition, participants were instructed to kick back in response to a tendon tap. The results were compared to reflexes in a resting baseline condition without voluntary movement. In a further condition, participants were instructed to kick forwards after a tap. Volunteers reported the perceived reflex contribution by repositioning the leg to the perceived maximum displacement to which the reflex moved the leg after each tendon tap. In the resting baseline condition, the reflex was accurately perceived. We found a near-unity slope of linear regressions of perceived on actual reflexive displacement. Both the slope value and the quality of regression fit in individual volunteers were significantly reduced when volunteers were instructed to generate voluntary backward kicks as soon as they detected the tap. In the kick forward condition, kinematic analysis showed continuity of reflex and voluntary movements, but the reflex contribution could be estimated from electromyography (EMG) recording on each trial. Again, participants' judgements of reflexes showed a poor relation to reflex EMG, in contrast to the baseline condition. In sum, we show that reflexes can be accurately perceived from afferent information. However, the presence of voluntary movement significantly impairs reflex perception. We suggest that perceptual separation between voluntary and reflex movement is poor at best. Our results imply that the brain has no clear marker for perceptually separating voluntary and involuntary movement. Attribution of body movement to voluntary or involuntary motor commands is surprisingly poor when both are present. PMID:24060990
Context-Specific Adaptation of Gravity-Dependent Vestibular Reflex Responses
Shelhamer, Mark J.
1999-01-01
Stabilization of the eyes and head during body movements is important for maintaining balance and keeping the images of objects stationary on our retinas. Impairment of this ability can lead to disorientation and reduced performance in sensorimotor tasks such as piloting of spacecraft. In the absence of a normal earth gravity field, the dynamics of head stabilization, and the interpretation of vestibular signals that sense gravity and linear acceleration, are subject to change. Transitions between different gravitoinertial force environments - as during different phases of space flight - provide an extreme test of the adaptive mechanisms that maintain these reflexive abilities. It is vitally important to determine human adaptive capabilities in such a circumstance, so that we can know to what extent the sensorimotor skills acquired in one gravity environment will transfer to others. Our work lays the foundation for understanding these capabilities, and for determining how we can aid the processes of adaptation and readaptation. An integrated set of experiments addresses this issue. We use the general approach of adapting some type of reflexive eye movement (saccades, the angular vestibulo-ocular reflex (AVOR), the linear vestibulo-ocular reflex (LVOR)), or the vestibulo-collic reflex (VCR), to a particular change in gain or phase in one condition of gravitoiner-tial force, and adapting to a different gain or phase (or asking for no change) in a second gravitoinertial force condition, and then seeing if the gravitoinertial force itself - the context cue - can recall the previously learned adapted responses. The majority of the experiments in the laboratory use the direction of vertical gaze or the direction of gravity (head tilt) as the context cue. This allows us to study context-specificity in a ground-based setting. One set of experiments, to be performed in parabolic flight, specifically uses the magnitude of gravitoinertial force as a context cue. This is a much better analog of the situation encountered in space flight. Various experiments investigate the behavioral properties, neurophysiological basis, and anatomical substrate of context-specific learning mechanisms. We use otolith (gravity) signals as the contextual cue for switching between adapted states of the saccadic system, the angular and linear vestibulo-ocular reflexes, and the VCR. (By LVOR we mean the oculomotor response - horizontal, vertical, and torsional - to linear translation of the head and body.) We are studying the effect of context on adaptation of saccade gain, phase and gain of the AVOR and LVOR, on ocular counterrolling (OCR) in response to static head tilt, and on head/neck reflexes (VCR) in response to rotation in different orientations. Such research is particularly germane to potential problems of postural and oculomotor control upon exposure to different gravitational environments.
How to Classify Reflexive Gorenstein Cones
Skarke, Harald
2012-01-01
Two of my collaborations with Max Kreuzer involved classification problems related to string vacua. In 1992 we found all 10,839 classes of polynomials that lead to Landau-Ginzburg models with c=9 (Klemm and Schimmrigk also did this); 7,555 of them are related to Calabi-Yau hypersurfaces. Later we found all 473,800,776 reflexive polytopes in four dimensions; these give rise to Calabi-Yau hypersurfaces in toric varieties. The missing piece - toric constructions that need not be hypersurfaces - are the reflexive Gorenstein cones introduced by Batyrev and Borisov. I explain what they are, how they define the data for Witten's gauged linear sigma model, and how one can modify our classification ideas to apply to them. I also present results on the first and possibly most interesting step, the classification of certain basic weights systems, and discuss limitations to a complete classification.
Creativity in ethnographic interviews : reflexive participatory observation
DEFF Research Database (Denmark)
Kauffmann, Lene Teglhus
2014-01-01
The article discusses interviews as participatory reflexive observation. It is based on experiences of interviewing policymakers and researchers about knowledge and evidence in health promotion. This particular group of informants challenged an approach to interviews as getting informants to describe their everyday work life. By employing a methodological framework focusing on reflexive processes, interviews became consensual interactions, and the content of the interviews turned out to be analyses, interpretations and meaning making, that is, knowledge production. Interpretation and meaning making drew on ideologies, norms and values central to the field and thereby the strategies employed by the informants as well as by the researcher could be seen as wayfaring strategies; creating the paths in the field as they go along. Such an approach to interviews opens up the creative character of knowledge production and points out the role of the researcher as an active participant in the creative process.
A new model of the acoustic reflex.
Longtin, A; Derome, J R
1986-01-01
A system-type model of the acoustic reflex in man is proposed with the intention of sheding light on certain of its nonlinear behaviors. This model is the first to incorporate into the multipath structure of the reflex arc the adaptation and recovery processes. Parameter distribution in the parallel pathways is based on the current knowledge on the stapedius muscle and on motoneuron pool organization. A piecewise linear system is used in modeling adaptation at onset and recovery at offset. The model is calibrated at 2000 Hz, a frequency for which all the important parameters are available. Two nonlinear behaviors of the adaptation rate are explained: the frequency and intensity dependence, related respectively to the frequency dependence of the feedback gain and to the sigmoidal shape of the closed-loop stimulus-response curve. Underlying physiological mechanisms are discussed, along with other plausible nonlinear models, and extensions of the model to other stimuli are suggested. PMID:3697403
Shelhamer, Mark; Goldberg, Jefim; Minor, Lloyd B.; Paloski, William H.; Young, Laurence R.; Zee, David S.
1999-01-01
Impairment of gaze and head stabilization reflexes can lead to disorientation and reduced performance in sensorimotor tasks such as piloting of spacecraft. Transitions between different gravitoinertial force (gif) environments - as during different phases of space flight - provide an extreme test of the adaptive capabilities of these mechanisms. We wish to determine to what extent the sensorimotor skills acquired in one gravity environment will transfer to others, and to what extent gravity serves as a context cue for inhibiting such transfer. We use the general approach of adapting a response (saccades, vestibuloocular reflex: VOR, or vestibulocollic reflex: VCR) to a particular change in gain or phase in one gif condition, adapting to a different gain or phase in a second gif condition, and then seeing if gif itself - the context cue - can recall the previously-learned adapted responses. Previous evidence indicates that unless there is specific training to induce context-specificity, reflex adaptation is sequential rather than simultaneous. Various experiments in this project investigate the behavioral properties, neurophysiological basis, and anatomical substrate of context-specific learning, using otolith (gravity) signals as a context cue. In the following, we outline the methods for all experiments in this project, and provide details and results on selected experiments.
Casazza, Peter G
1989-01-01
This monograph provides a structure theory for the increasingly important Banach space discovered by B.S. Tsirelson. The basic construction should be accessible to graduate students of functional analysis with a knowledge of the theory of Schauder bases, while topics of a more advanced nature are presented for the specialist. Bounded linear operators are studied through the use of finite-dimensional decompositions, and complemented subspaces are studied at length. A myriad of variant constructions are presented and explored, while open questions are broached in almost every chapter. Two appendices are attached: one dealing with a computer program which computes norms of finitely-supported vectors, while the other surveys recent work on weak Hilbert spaces (where a Tsirelson-type space provides an example).
Arakeri’s Reflex: an Alternative Pathway for Dento-Cardiac Reflex Mediated Syncope
Directory of Open Access Journals (Sweden)
Veena Arali
2010-03-01
Full Text Available Introduction: Dentocardiac reflex, a variant of trigeminocardiac reflex elicited specifically during tooth extraction procedures in den-tal/maxillofacial surgery and is believed to cause syncope with an afferent link mediated by posterior superior alveolar nerve. Another variant of trigeminocardiac reflex which is also of interest to the oral and maxillofacial surgeon is oculocardiac reflex which can be triggered by direct or indirect manipulation of eye globe or muscles around it.The hypothesis: Excessive or injudicious pressure or manipulations around the maxillary first molars during extraction procedure are as-sociated with maximum incidence of bradycardia and hypotension than around incisor/ canine/ third molars. This is because; the pressure on eye globe and ophthalmic rectus muscle is maximum during extraction of first molar than incisor/canine and third molars. This observation led us to postulate an alternative pathway for dentocardiac reflex mediated syncope which may possibly justify the maxillary first molar region as a prone factor for the trigger. Evaluation of the hypothesis: Present hypothesis may not confer the specific factor responsible for switch in autonomic response in syncope origin during the tooth extraction procedure, but may provide a clue to where we should be looking.
Mechanically evoked perioral reflexes in infants.
Barlow, S M; Finan, D S; Rowland, S G
1992-12-18
Mechanically evoked activity in the superior and inferior segments of the orbicularis oris muscle was sampled in several young infants using a specially designed position-servo linear motor and a pacifier instrumented with eight miniature EMG electrodes. Unilateral stimulation of lip vermilion resulted in short latency, bilateral activation of the upper and lower lip recording sites. The ontogenesis of facial reflex sensitivity to mechanical inputs is discussed in relation to the acquisition of motor skills, including speech and smiling. PMID:1493544
Axially evoked postural reflexes: influence of task
Govender, Sendhil; Dennis, Danielle L.; Colebatch, James G.
2014-01-01
Postural reflexes were recorded in healthy subjects (n = 17) using brief axial accelerations and tap stimuli applied at the vertebra prominens (C7) and manubrium sterni. Short latency (SL) responses were recorded from the soleus, hamstrings and tibialis anterior muscles and expressed as a percentage of the background EMG prior to stimulus onset. In the majority of postural conditions tested, subjects were recorded standing erect and leaning forward with their feet together. The SL response ...
A Reflexive Extension to Arachne's Aspect Language
Loriant, Nicolas; Se?gura-devillechaise, Marc; Fritz, Thomas; Menaud, Jean-marc
2006-01-01
Aspect weaving at run time has proven to be an effective way of implementing software evolution. Nevertheless, it is often hard to achieve adequate modularization and reusability in face of run time and implementation issues. Arachne is an AO system that features a run time aspect weaver for C applications, and a language close to the C syntax. In this paper we present a reflexive extension of Arachne's aspect language. We show through extracts of a deadlock detection aspect, how this extensi...
The learnability of the reflexive in Esperanto
Jansen, W.
2012-01-01
Esperanto is a planned language for international use. Much of its grammar is easily learnable by speakers with all sorts of linguistic backgrounds. The adjectival reflexive possessive is one of the elements in the grammar which is experienced by many learners as a serious difficulty. It is also one of the topics that has caused many debates among scholars and language users in general, who, despite 125 years of intensive linguistic development, have not managed to come up with a universally ...
Photic sneeze reflex in nephropathic cystinosis.
Katz, B.; Melles, R. B.; Swenson, M. R.; Schneider, J. A.
1990-01-01
Photic induced sneeze is a reflex that occurs in certain individuals after exposure to bright light. Cystinosis is an autosomal recessive inborn error of metabolism in which nonprotein cystine accumulates within lysosomes. The pathognomonic ocular manifestation of cystinosis is corneal crystal deposition. We observed photic induced sneezes during ophthalmoscopic examination in five of 19 patients with nephropathic cystinosis (26%). We report on this observation and discuss possible pathophysi...
Reflex anuria affecting both kidneys following hysterectomy
Gholyaf Mahmoud; Afzali Saeed; Babolhavaegi Hoshang; Rahimi Abolfazl; Wagharseyedayn Seyed
2009-01-01
In situations when there is unilateral ureteral obstruction, the contralateral kidney retains its normal function. In rare instances however, it has been reported that unilateral ureteral obstruction can lead to reflex anuria (RA) and acute renal failure (ARF). Even more unusually, RA with ARF can occur without organic obstruction due to ureteric manipulation during pelvic surgery. We report a 78- year-old woman, who underwent hysterectomy because of endometrial carcinoma. She developed ARF e...
Exaggerated postural vasoconstrictor reflex in Raynaud's phenomenon.
Chant, A. D. B.
1987-01-01
The central and local regulation of capillary blood flow in the finger was studied by the local xenon-133 washout technique in women with primary Raynaud's phenomenon, men with vibration induced white finger, and their respective sex matched controls. The vasoconstrictor response to venous stasis of 40 mm Hg elicited by local reflex was normal in both types of Raynaud's phenomenon. Change in posture from lying to sitting induced vasoconstriction in all groups, which was abolished by proximal ...
Basic Gravitational Reflexes in the Larval Frog
Cochran, Stephen L.
1996-01-01
This investigation was designed to determine how a primitive vertebrate, the bullfrog tadpole, is able to sense and process gravitational stimuli. Because of the phylogenetic similarities of the vestibular systems in all vertebrates, the understanding of the gravitational reflexes in this relatively simple vertebrate should elucidate a skeletal framework on a elementary level, upon which the more elaborate reflexes of higher vertebrates may be constructed. The purpose of this study was to understand how the nervous system of the larval amphibian processes gravitational information. This study involved predominantly electrophysiological investigations of the isolated, alert (forebrain removed) bullfrog tadpole head. The focus of these experiments is threefold: (1) to understand from whole extraocular nerve recordings the signals sent to the eye following static gravitational tilt of the head; (2) to localize neuronal centers responsible for generating these signals through reversible pharmacological ablation of these centers; and (3) to record intracellularly from neurons within these centers in order to determine the single neuron's role in the overall processing of the center. This study has provided information on the mechanisms by which a primitive vertebrate processes gravitational reflexes.
Directory of Open Access Journals (Sweden)
Stransky Albert
2008-04-01
Full Text Available Abstract Fifty spontaneously breathing pentobarbital-anesthetized cats were used to determine the incidence rate and parameters of short reflex expirations induced by mechanical stimulation of the tracheal mucosa (ERt. The mechanical stimuli evoked coughs; in addition, 67.6% of the stimulation trials began with ERt. The expiration reflex mechanically induced from the glottis (ERg was also analyzed (99.5% incidence, p In an additional 8 cats, the effect of codeine administered via the vertebral artery was tested. Codeine, in a dose (0.03 mg/kg that markedly suppressed cough did not significantly alter either the incidence rate or magnitudes of ERt. In the anesthetized cat the ERt induced by mechanical stimulation of the trachea was similar to the ERg from the glottis. These two reflex responses differ substantially only in the frequency of occurrence in response to mechanical stimulus and in the intensity of motor output.
Dopamine agonists suppress visual-cortical reflex myoclonus.
Obeso, J. A.; Artieda, J.; Tun?o?n, T.; Luquin, M. R.; Marti?nez Lage, J. M.
1985-01-01
Two patients with a diagnosis of olivo-ponto-cerebellar atrophy developed cortical reflex myoclonus to visual (flash) and somaesthetic stimuli. Oral treatment with levodopacarbidopa (1000/100 mg) or subcutaneous administration of apomorphine (1 mg) abolished the visually-triggered myoclonus, without modifying reflex myoclonus to electrical or tactile stimulation. Intravenous administration of lisuride (0.1 mg) produced a marked reduction in both types of reflex myoclonus. These results indica...
Reducing occurrences of an asymmetrical tonic neck reflex.
Lee, J M; Mahler, T J; Westling, D L
1985-05-01
A custom-designed foam rubber headpiece was used during lunch with a multiply handicapped child to reduce the occurrences of an asymmetrical tonic neck reflex. After the inappropriate reflex was inhibited, the apparatus was gradually faded out by cutting away sections of the rubber. Ultimately, the headpiece was completely eliminated and the asymmetrical tonic neck reflex maintained a zero level of occurrence during lunch periods. Concomitantly, there was an increase in correct bites of food. PMID:4003456
The Role of Transformational Leadership in Enhancing Team Reflexivity
Schippers, M. C.; Hartog, D. N. Den; Koopman, P. L.; Knippenberg, D. L.
2007-01-01
Team reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to develop theorizing around the determinants of reflexivity. From an applied perspective, leadership is a very relevant factor. The current study is a first step in the development of such a theory, and add...
Coactivation of leg reflexes in the stick insect
Cruse, Holk; Dautenhahn, Kerstin; Schreiner, H.
1992-01-01
Each leg of a standing stick insect acts as a height controller. The leg contains several joints. Most of these joints are known to be controlled by feedback loops which are the basis of resistance reflexes (review Bässler 1983). This leads to the question of whether the resistance reflex of the whole leg can be understood as a simple, vectorial sum of the individual reflexes provided by the different joints, or whether additional properties emerge by simultaneous stimulation of several join...
On the L-characteristic of nonlinear superposition operators in lp-spaces
International Nuclear Information System (INIS)
In this paper we describe the L-characteristic of the nonlinear superposition operator F(x) f(s,x(s)) between two Banach spaces of functions x from N to R. It was shown that L-characteristic of the nonlinear superposition operator which acts between two Lebesgue spaces has so-called ?-convexity property. In this paper we show that L-characteristic of the operator F (between two Banach spaces) has the convexity property. It means that the classical interpolation theorem of Reisz-Thorin for a linear operator holds for the nonlinear operator superposition which acts between two Banach spaces of sequences. Moreover, we consider the growth function of the operator superposition in mentioned spaces and we show that one has the logarithmically convexity property. (author). 7 refs
Axially evoked postural reflexes: influence of task.
Govender, Sendhil; Dennis, Danielle L; Colebatch, James G
2015-01-01
Postural reflexes were recorded in healthy subjects (n = 17) using brief axial accelerations and tap stimuli applied at the vertebra prominens (C7) and manubrium sterni. Short latency (SL) responses were recorded from the soleus, hamstrings and tibialis anterior muscles and expressed as a percentage of the background EMG prior to stimulus onset. In the majority of postural conditions tested, subjects were recorded standing erect and leaning forward with their feet together. The SL response was larger for soleus than for the hamstrings during standing (soleus vs hamstrings; 70.4 vs 28.1%), whereas the opposite occurred during kneeling (25.3 vs 127.3%). Concordant head and trunk accelerations produced larger SL responses than discordant accelerations for soleus and hamstrings, but the evoked excitatory response was independent of head direction and as expected for the direction of truncal acceleration. Postural reflexes for soleus and tibialis anterior were strongly affected by conditions that posed a significant threat to postural stability; stimulation at C7 was associated with significant SL enhancement for soleus during anterior lean while sternal stimulation showed SL enhancement for tibialis anterior during posterior lean. Cutaneous anaesthesia applied over the C7 stimulation site had no significant effect on EMG responses, nor did vision or surface type (rigid or compliant). This study provides further evidence that postural reflexes produced by brief axial accelerations are independent of cutaneous receptors, vestibular afferents and ankle proprioceptors, and demonstrates that postural tasks and truncal orientation significantly affect the evoked response, consistent with a role in stabilising posture. PMID:25300958
Hatori, Osamu; Takaggi, Hiroyuki
2009-01-01
Let $A$ and $B$ be unital semisimple commutative Banach algebras and $T$ a map from the invertible group $A^{-1}$ onto $B^{-1}$. Linearity and multiplicativity of the map are not assumed. We consider the hypotheses on $T$: (1) $\\sigma (TfTg)=\\sigma (fg)$; (2) $\\sigma_{\\pi}(TfTg-\\alpha)\\cap \\sigma_{\\pi}(fg-\\alpha)\
Central limit theorem for the Banach-valued weakly dependent random variables
International Nuclear Information System (INIS)
The central limit theorem (CLT) for the Banach-valued weakly dependent random variables is proved. In proving CLT convergence of finite-measured (i.e. cylindrical) distributions is established. A weak compactness of the family of measures generated by a certain sequence is confirmed. The continuity of the limiting field is checked
On solvability of some quadratic functional-integral equation in Banach algebra
International Nuclear Information System (INIS)
Using the technique of a suitable measure of non-compactness in Banach algebra, we prove an existence theorem for some functional-integral equations which contain, as particular cases, a lot of integral and functional-integral equations that arise in many branches of nonlinear analysis and its applications. Also, the famous Chandrasekhar's integral equation is considered as a special case. (author)
Gorini, C.; Jameson, H. S.; Mendelowitz, D.
2009-01-01
Stimulation of the trigeminal nerve evokes a dramatic decrease in heart rate and blood pressure, and this reflex has generally been termed the trigeminocardiac reflex. A subset of the trigeminocardiac reflex is the diving reflex in which the nasal mucosa is stimulated with water or air-borne chemical irritants. Activation of the diving reflex evokes a pronounced bradycardia, mediated by increased parasympathetic cardiac activity, and is the most powerful autonomic reflex. However, exaggeratio...
Berckmoes, Ben
2012-01-01
We prove a uniformly continuous linear extension principle in topological vector spaces from which we derive a very short and canonical construction of the Lebesgue integral of Banach space valued maps on a finite measure space. The Vitali Convergence Theorem and the Riesz-Fischer Theorem are shown to follow as easy consequences from our construction.
Sympathetic reflex control of blood flow in human peripheral tissues.
DEFF Research Database (Denmark)
Henriksen, O
1991-01-01
Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human skeletal muscle, cutaneous and subcutaneous tissues of the limbs indicate that the situation is more complex. Measurements have been carried out during acute as well as chronic sympathetic denervation. Spinal sympathetic reflex mechanisms have been evaluated in tetraplegic patients, where supraspinal sympathetic vasoconstrictor reflexes are blocked. Blood flow has been measure by the local 133Xe-technique. The results indicate the presence of spinal as well as supraspinal sympathetic vasoconstrictor reflexes to human peripheral tissues. Especially is emphasized the presence of a local sympathetic veno-arteriolar axon reflex which is elicited by increase in venous transmural pressure of more than about 25 mm Hg. Finally, centrally elicited vasoconstrictor activity is modified by simultaneously activating the local veno-arteriolar axon reflex or vice versa by means of an intraneuronal impulse inhibition due to collision of normodromically and antidromically conducted impulses in efferent sympathetic vasoconstrictor fibers. The evidence obtained suggests that sympathetic vasoconstrictor reflexes to postural changes are complex and highly differentiated.
Reflexivity of Discomfort in Insider-Outsider Educational Research
Hamdan, Amani K.
2009-01-01
This paper discusses my position as an Arab Muslim woman researcher who is affiliated with a Western university, researching Arab Muslim Canadian women. I discuss how reflexivity has emerged as an element of my research endeavours. Various notions of reflexivity in educational research have been expressed in the literature, yet I focus on what it…
Iris Pigmentation and Fractionated Reaction and Reflex Time.
Hale, Bruce D.; And Others
Behavioral measures, fractionated reaction and reflex times by means of electromyography, were used to determine if the eye color differences are found in the central or peripheral regions of the nervous system. The purpose of this research was to determine the truth of the hypothesis that dark-eyed individuals have faster reflex and reaction time…
Reflexive obstacle avoidance for kinematically-redundant manipulators
Karlen, James P.; Thompson, Jack M., Jr.; Farrell, James D.; Vold, Havard I.
1989-01-01
Dexterous telerobots incorporating 17 or more degrees of freedom operating under coordinated, sensor-driven computer control will play important roles in future space operations. They will also be used on Earth in assignments like fire fighting, construction and battlefield support. A real time, reflexive obstacle avoidance system, seen as a functional requirement for such massively redundant manipulators, was developed using arm-mounted proximity sensors to control manipulator pose. The project involved a review and analysis of alternative proximity sensor technologies for space applications, the development of a general-purpose algorithm for synthesizing sensor inputs, and the implementation of a prototypical system for demonstration and testing. A 7 degree of freedom Robotics Research K-2107HR manipulator was outfitted with ultrasonic proximity sensors as a testbed, and Robotics Research's standard redundant motion control algorithm was modified such that an object detected by sensor arrays located at the elbow effectively applies a force to the manipulator elbow, normal to the axis. The arm is repelled by objects detected by the sensors, causing the robot to steer around objects in the workspace automatically while continuing to move its tool along the commanded path without interruption. The mathematical approach formulated for synthesizing sensor inputs can be employed for redundant robots of any kinematic configuration.
Partial inner product spaces theory and applications
Antoine, Jean-Pierre
2009-01-01
Partial Inner Product (PIP) Spaces are ubiquitous, e.g. Rigged Hilbert spaces, chains of Hilbert or Banach spaces (such as the Lebesgue spaces Lp over the real line), etc. In fact, most functional spaces used in (quantum) physics and in signal processing are of this type. The book contains a systematic analysis of PIP spaces and operators defined on them. Numerous examples are described in detail and a large bibliography is provided. Finally, the last chapters cover the many applications of PIP spaces in physics and in signal/image processing, respectively. As such, the book will be useful both for researchers in mathematics and practitioners of these disciplines.
Contractive projections and operator spaces
Neal, Matthew; Russo, Bernard
2002-01-01
Parallel to the study of finite dimensional Banach spaces, there is a growing interest in the corresponding local theory of operator spaces. We define a family of Hilbertian operator spaces H_n^k,0< k < n+1, generalizing the row and column Hilbert spaces R_n,C_n and show that an atomic subspace X of B(H) which is the range of a contractive projection on B(H) is isometrically completely contractive to a direct sum of the H_n^k and Cartan factors of types 1 to 4. In particular...
More smoothly real compact spaces
Kriegl, A; Kriegl, Andreas; Michor, Peter W.
1993-01-01
A topological space $X$ is called $\\Cal A$-real compact, if every algebra homomorphism from $\\Cal A$ to the reals is an evaluation at some point of $X$, where $\\Cal A$ is an algebra of continuous functions. Our main interest lies on algebras of smooth functions. In \\cite{AdR} it was shown that any separable Banach space is smoothly real compact. Here we generalize this result to a huge class of locally convex spaces including arbitrary products of separable Fr\\'echet spaces.
Effects of Bed Rest on Conduction Velocity of the Triceps Surae Stretch Reflex and Postural Control
Reschke, M. F.; Wood, S. J.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Esteves, J. T.; Taylor, L. C.; DeDios, Y. E.; Harm, D. L.
2011-01-01
Despite rigorous exercise and nutritional management during space missions, astronauts returning from microgravity exhibit neuromuscular deficits and a significant loss in muscle mass in the postural muscles of the lower leg. Similar changes in the postural muscles occur in subjects participating in long-duration bed rest studies. These adaptive muscle changes manifest as a reduction in reflex conduction velocity during head-down bed rest. Because the stretch reflex encompasses both the peripheral (muscle spindle and nerve axon) and central (spinal synapse) components involved in adaptation to calf muscle unloading, it may be used to provide feedback on the general condition of neuromuscular function, and might be used to evaluate the effectiveness of countermeasures aimed at preserving muscle mass and function during periods of unloading. Stretch reflexes were measured on 18 control subjects who spent 60 to 90 days in continuous 6 deg head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 degrees at a peak velocity of about 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender. Computerized posturography was also conducted on these same subjects before and after bed rest as part of the standard measures. Peak-to-peak sway was measured during Sensory Organization Tests (SOTs) to evaluate changes in the ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Although no gender differences were found, a significant increase in reflex latency and a significant decrease in CV were observed during the bed rest period, with a return to baseline 3 to 5 days after bed rest, depending on the duration of bed rest. In addition, a relationship between CV and loss of muscle strength in the lower leg was observed post bed rest for most subjects. Immediately post-bed rest, most subjects showed decreased performance on SOTs, with the greater decrements on sway-referenced support and head movement conditions. Post-bed rest decrements were less than typically observed following spaceflight. Decrements in postural control and the stretch reflex can be primarily attributed to the unloading mechanisms this ground-based analog provides. The stretch reflex is a concise test measurement that can be obtained during the head-down phase of bed rest, as it does not interfere with the bed rest paradigm. This makes it an ideal tool that can detect, early on, whether a countermeasure is successful in preserving muscle function.
Sex differences in nociceptive withdrawal reflex and pain perception.
Mylius, Veit; Kunz, Miriam; Schepelmann, Karsten; Lautenbacher, Stefan
2005-09-01
Experimentally induced pain often reveals sex differences, with higher pain sensitivity in females. The degree of differences has been shown to depend on the stimulation and assessment methods. Since sex differences in pain develop anywhere along the physiological and psychological components of the nociceptive system, we intended to compare the nociceptive flexion reflex (NFR) as a more physiological (spinal) aspect of pain procession to the verbal pain report of intensity and unpleasantness as the more psychological (cortical) aspect. Twenty female and twenty male healthy university students were investigated by use of nociceptive flexion reflex threshold (staircase method) after electrical stimulation of the N. suralis. Furthermore, we assessed supra-threshold reflex responses (latency, amplitude and area) by applying 10 stimuli 5 mA above reflex threshold. Following each stimulation, the subjects provided pain ratings of intensity and unpleasantness on a visual analogue scale. Females exhibited marked lower nociceptive flexion reflex thresholds than males, while the supra-threshold reflex response tailored to the individual reflex threshold did not show any significant differences. The verbal pain ratings, corrected for NFR threshold, were not found to differ significantly. The large sex differences in nociception that were present in NFR threshold but not in the pain ratings corroborate the hypothesis that spinal processes contribute substantially to sex differences in pain procession. PMID:16338828
Is Palmomental Reflex Actually A Part of Feeding Behavior?
Directory of Open Access Journals (Sweden)
Burcu UGUREL
2009-06-01
Full Text Available Purpose and hypothesis: Palmomental reflex is considered to be a primitive reflex and related to pathologic processes. The reflex can be obtained from every individual by electrophysiologic measures. There have been no reports concerning submental, orbicularis oris and masseter muscle reflex responses provoked by median nerve stimulation in healthy elderly individuals and patients with dementia up to now.Method: In the present study the median nerve was stimulated below the pain threshold and activities obtained from mental, submental, orbicularis oris and masseter muscles were recorded simultaneously in patients with dementia (n = 18 and in healthy elderly individuals (n = 18.Result: Latencies obtained from mental, submental, orbicularis oris and masseter muscles were approximately recorded within 80 – 100 milliseconds and the differences between the latencies were not statistically significant.Conclusion: The palmomental reflex seems to be an activity co-occurring with functions like mouth opening and swallowing, and reflecting hand – mouth reaction, rather than being only a primitive reflex involving mental muscle. We believe close temporal relationship among the activities of mental, submental, orbicularis oris and masetter muscles after hand stimulation requires these reflexes to be investigated in the physiology of hand and mouth coordination in further studies.
Distrofia simpático-reflexa Reflex sympathetic dystrophy
Directory of Open Access Journals (Sweden)
Ana P. N. Lotito
2004-04-01
Full Text Available OBJETIVO: Descrever as características clínicas, laboratoriais e terapêuticas de oito crianças com distrofia simpático-reflexa. DESCRIÇÃO: Foram analisados retrospectivamente oito casos de distrofia simpático-reflexa. O diagnóstico foi baseado na presença de dor no segmento distal de um membro, edema local, alterações vasomotoras e de sensibilidade. Dentre os oito pacientes com distrofia simpático-reflexa, dois eram portadores de lúpus eritematoso sistêmico, um de artrite idiopática juvenil e um de trombastenia de Glanzmann. Quatro eram meninas, e a média de idade foi de 11,5 anos. Os membros inferiores foram acometidos na maioria dos pacientes (7/8, e as características clínicas mais marcantes foram dor, edema e alterações vasomotoras da extremidade afetada (7/8, incapacitação funcional (7/8 e alterações de sensibilidade (3/8. A velocidade de hemossedimentação esteve alterada em três pacientes, e a cintilografia músculo-esquelética em cinco. Todos os pacientes receberam antiinflamatórios não-hormonais e fisioterapia, com melhora clínica observada em sete pacientes em até 6 meses de tratamento. Três pacientes foram submetidos à acupuntura, com boa resposta. Um paciente teve curso de difícil controle, tendo recebido antidepressivos tricíclicos e apresentando melhora após mais de 1 ano de tratamento. COMENTÁRIOS: A distrofia simpático-reflexa é uma doença que deve ser incluída no diagnóstico diferencial das dores em membros na infância, para que se estabeleça o diagnóstico precocemente, evitando-se, assim, prejuízo funcional a médio e longo prazo.OBJECTIVE: To describe eight patients with reflex sympathetic dystrophy in terms of clinical and laboratory characteristics and treatment. DESCRIPTION: Eight children (four girls with reflex sympathetic dystrophy were retrospectively analyzed. The diagnosis of reflex sympathetic dystrophy was based on the presence of pain in the distal extremities, local edema, vasomotor instability and impairment of sensibility. Two patients had associated systemic lupus erythematosus, one had juvenile idiopathic arthritis and one had Glanzmann's thrombasthenia. Mean age was 11.5 years. Most of the patients had lower extremity involvement (7/8. The most important clinical signs were pain, edema and vasomotor instability in the affected extremity (8/8, functional impairment (7/8, and impaired sensibility (3/7. The erythrocyte sedimentation rate was abnormal in three patients and the bone scans in five. All patients received non-steroidal anti-inflammatory drugs and physical therapy with improvement of the symptoms in seven patients, until six months of treatment. Three patients were submitted to acupuncture with good response. One patient had a severe disease and received tricyclic antidepressants, with improvement more than one year after. COMMENTS: Reflex sympathetic dystrophy should be included as part of the differential diagnosis of limb pains of childhood, so that physicians can make an earlier diagnosis and prevent functional impairment.
Distrofia simpático-reflexa / Reflex sympathetic dystrophy
Scientific Electronic Library Online (English)
Ana P. N., Lotito; Lúcia M. M. A., Campos; Marialda H. P., Dias; Clovis A. A., Silva.
2004-04-01
Full Text Available SciELO Brazil | Languages: English, Portuguese Abstract in portuguese OBJETIVO: Descrever as características clínicas, laboratoriais e terapêuticas de oito crianças com distrofia simpático-reflexa. DESCRIÇÃO: Foram analisados retrospectivamente oito casos de distrofia simpático-reflexa. O diagnóstico foi baseado na presença de dor no segmento distal de um membro, edem [...] a local, alterações vasomotoras e de sensibilidade. Dentre os oito pacientes com distrofia simpático-reflexa, dois eram portadores de lúpus eritematoso sistêmico, um de artrite idiopática juvenil e um de trombastenia de Glanzmann. Quatro eram meninas, e a média de idade foi de 11,5 anos. Os membros inferiores foram acometidos na maioria dos pacientes (7/8), e as características clínicas mais marcantes foram dor, edema e alterações vasomotoras da extremidade afetada (7/8), incapacitação funcional (7/8) e alterações de sensibilidade (3/8). A velocidade de hemossedimentação esteve alterada em três pacientes, e a cintilografia músculo-esquelética em cinco. Todos os pacientes receberam antiinflamatórios não-hormonais e fisioterapia, com melhora clínica observada em sete pacientes em até 6 meses de tratamento. Três pacientes foram submetidos à acupuntura, com boa resposta. Um paciente teve curso de difícil controle, tendo recebido antidepressivos tricíclicos e apresentando melhora após mais de 1 ano de tratamento. COMENTÁRIOS: A distrofia simpático-reflexa é uma doença que deve ser incluída no diagnóstico diferencial das dores em membros na infância, para que se estabeleça o diagnóstico precocemente, evitando-se, assim, prejuízo funcional a médio e longo prazo. Abstract in english OBJECTIVE: To describe eight patients with reflex sympathetic dystrophy in terms of clinical and laboratory characteristics and treatment. DESCRIPTION: Eight children (four girls) with reflex sympathetic dystrophy were retrospectively analyzed. The diagnosis of reflex sympathetic dystrophy was based [...] on the presence of pain in the distal extremities, local edema, vasomotor instability and impairment of sensibility. Two patients had associated systemic lupus erythematosus, one had juvenile idiopathic arthritis and one had Glanzmann's thrombasthenia. Mean age was 11.5 years. Most of the patients had lower extremity involvement (7/8). The most important clinical signs were pain, edema and vasomotor instability in the affected extremity (8/8), functional impairment (7/8), and impaired sensibility (3/7). The erythrocyte sedimentation rate was abnormal in three patients and the bone scans in five. All patients received non-steroidal anti-inflammatory drugs and physical therapy with improvement of the symptoms in seven patients, until six months of treatment. Three patients were submitted to acupuncture with good response. One patient had a severe disease and received tricyclic antidepressants, with improvement more than one year after. COMMENTS: Reflex sympathetic dystrophy should be included as part of the differential diagnosis of limb pains of childhood, so that physicians can make an earlier diagnosis and prevent functional impairment.
International Nuclear Information System (INIS)
The main purpose of this paper is the theoretical study and the development of a technique for designing. A low power Reflex-Klystron, in order to construct it in the graduated section laboratories of the Instituto Politecnico Nacional. It is pretended to attain a power of 15-45 m W in frequencies of 8-10 GHz with low acceleration potentials (300-400 V) and electric current of 15-25 m A; the device will be mechanically tuned and will have a fine tuning through the potential of the reflector (150-180 V negative with respect to the resonator). The International System of Units is used in this thesis. (Author)
Interindividual differences in H reflex modulation during normal walking
DEFF Research Database (Denmark)
Simonsen, Erik B; Dyhre-Poulsen, Poul
2002-01-01
Based on previous studies, at least two different types of soleus Hoffmann (H) reflex modulation were likely to be found during normal human walking. Accordingly, the aim of the present study was to identify different patterns of modulation of the soleus H reflex and to examine whether or not subjects with different H reflex modulation would exhibit different walking mechanics and different EMG activity. Fifteen subjects walked across two force platforms at 4.5 km/h (+/-10%) while the movements were recorded on video. The soleus H reflex and EMG activity were recorded separately during treadmill walking at 4.5 km/h. Using a two-dimensional analysis joint angles, angular velocities, accelerations, linear velocities and accelerations were calculated, and net joint moments about the ankle, knee and hip joint were computed by inverse dynamics from the video and force plate data. Six subjects (group S) showed a suppressed H reflex during the swing phase, and 9 subjects (group LS) showed increasing reflex excitability during the swing phase. The plantar flexor dominated moment about the ankle joint was greater for group LS. In contrast, the extensor dominated moment about the knee joint was greater for the S group. The hip joint moment was similar for the groups. The EMG activity in the vastus lateralis and anterior tibial muscles was greater prior to heel strike for the S group. These data indicate that human walking exhibits at least two different motor patterns as evaluated by gating of afferent input to the spinal cord, by EMG activity and by walking mechanics. Increasing H reflex excitability during the swing phase appears to protect the subject against unexpected perturbations around heel strike by a facilitated stretch reflex in the triceps surae muscle. Alternatively, in subjects with a suppressed H reflex in the swing phase the knee joint extensors seem to form the primary protection around heel strike.
Taylor, Myra; Houghton, Stephen; Chapman, Elaine
2004-01-01
The present research studied the symptomatologic overlap of AD/HD behaviours and retention of four primitive reflexes (Moro, Tonic Labyrinthine Reflex [TLR], Asymmetrical Tonic Neck Reflex [ATNR], Symmetrical Tonic Neck Reflex [STNR]) in 109 boys aged 7-10 years. Of these, 54 were diagnosed with AD/HD, 34 manifested sub-syndromal coordination,…
Rank 2 reflexive sheaves on a smooth threefold
Valenzano, Mario
2004-01-01
We show that some properties of rank 2 reflexive sheaves true on P3 can be extended to a wide class of smooth projective threefolds. In particular, we extend the Hartshorne-Serre correspondence between rank 2 reflexive sheaves and curves lying on the threefold. Secondly, we establish some cohomological conditions in order that a rank 2 reflexive sheaf is locally free or a split bundle, i.e., which is equivalent, that an equidimensional, locally Cohen-Macaulay and generically local complete in...
The functional and pragmatic features of assonance phraseological reflexes
Directory of Open Access Journals (Sweden)
Shkapenko T.
2014-09-01
Full Text Available This paper analyzes a specific group of phraseological reflexes based on an assonance rhyme with an initial interrogative utterance. Assonance phraseological reflexes cannot perform a descriptive or nominative function acting in the process of verbal interaction only as markers of pragmatic intentions. Therefore, the attempts to describe them in terms of traditional semantics prove unsuccessful. A proper study of assonance phraseological reflexes is possible only in the framework of speech act theory. From the cognitive perspective, these units of speech are an example of a language game typical of speech subcultures.
Widths of embeddings of 2-microlocal Besov spaces
Zhang, Shun
2011-01-01
We consider the asymptotic behaviour of the approximation, Gelfand and Kolmogorov numbers of compact embeddings between 2-microlocal Besov spaces with weights defined in terms of the distance to a $d$-set $U\\subset \\mathbb{R}^n$. The sharp estimates are shown in most cases, where the quasi-Banach setting is included.
Ogilvie, J; Simpson, D A; Clarke, R W
1999-01-01
The excitability of the heel-gastrocnemius withdrawal reflex pathway has been monitored in rabbits undergoing surgical preparation for electrophysiological experimentation under Saffan anaesthesia. Reflexes were evoked by percutaneous electrodes inserted at the heel and recorded as electromyograph signals from the ipsilateral medial gastrocnemius muscle. Two levels of surgery were carried out. The "full surgical" preparation was performed under deep Saffan anaesthesia. The trachea, carotid artery, jugular vein and intrathecal space (via a small laminectomy at L1) were cannulated, the animals were decerebrated by suction, and the left hindlimb was immobilized by screw clamps applied to the tibia and the femur. The sciatic nerve and its branches were exposed by bisection of the posterior biceps muscle and the anaesthetic was withdrawn. In the "reduced surgery" preparation, procedures were carried out with a lighter level of Saffan anaesthesia and operated tissues were infiltrated with local anaesthetic. Only the cannulations were performed in these animals. The excitability of the heel-gastrocnemius reflex declined throughout the full surgical preparation, with the median threshold increasing from 0.8 to 4.2 mA (n=19) and responses to suprathreshold stimuli reducing in size. Most of this effect was reversed after surgery was complete and anaesthesia withdrawn subsequent to decerebration. There were no significant changes in reflex excitability during the reduced surgery preparation (n = 15). Animals prepared by each of these protocols were given increasing intrathecal doses of either the selective alpha2-adrenoceptor antagonist RX 821002 (0.3 to 300 microg) or the serotonin/5-hydroxytryptamine (5-HT)1A-receptor antagonist WAY-100635 (0.01 to 30 microg). Both drugs caused significant, dose-dependent increases in reflex responses, to four to six times pre-drug control in both groups of animals. There were no differences in the effects on reflexes of either drug between the preparations. Thus, surgical preparation of decerebrated rabbits for electrophysiological recording results in depression of hindlimb withdrawal reflexes, although much of this effect did not persist beyond the completion of surgery. Tonic monoaminergic inhibition of reflexes was present to the same extent in both preparations investigated and is not therefore an epiphenomenon of the way in which the animals were prepared. PMID:10362312
Countable Degree-1 Saturation of Certain C*-Algebras Which Are Coronas of Banach Algebras
Voiculescu, Dan-virgil
2013-01-01
We study commutants modulo some normed ideal of n-tuples of operators which satisfy a certain approximate unit condition relative to the ideal. We obtain results about the quotient of these Banach algebras by their ideal of compact operators being C*-algebras which have the countable degree-1 saturation property in the model-theory sense of I. Farah and B. Hart. We also obtain results about quasicentral approximate units, multipliers and duality.
A note on power values of generalized derivation in prime ring and noncommutative Banach algebras
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Shervin Sahebi
2014-05-01
Full Text Available Let $R$ be a prime ring with extended centroid $C$?, ?$H$ a generalized derivation of $R$ and $n\\geq 1$ a fixed integer?. ?In this paper we study the situations?: ?(1? ?If $(H(xy^n=(H(x^n(H(y^n$ for all? ?$x?, ?y \\in R$;? ?(2 obtain some related result in case $R$ is? ?a noncommutativeBanach algebra and $H$ is continuous? ?or spectrally bounded?.
Modified van der Pauw method based on formulas solvable by the Banach fixed point method
Cie?li?ski, Jan L
2012-01-01
We propose a modification of the standard van der Pauw method for determining the resistivity and Hall coefficient of flat thin samples of arbitrary shape. Considering a different choice of resistance measurements we derive a new formula which can be numerically solved (with respect to sheet resistance) by the Banach fixed point method for any values of experimental data. The convergence is especially fast in the case of almost symmetric van der Pauw configurations (e.g., clover shaped samples).
Fuzzy optimization for portfolio selection based on Embedding Theorem in Fuzzy Normed Linear Spaces
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Solatikia Farnaz
2014-05-01
Full Text Available Background: This paper generalizes the results of Embedding problem of Fuzzy Number Space and its extension into a Fuzzy Banach Space C(? × C(?, where C(? is the set of all real-valued continuous functions on an open set ?.
[A method for recording the human periodontal muscular reflex].
Malevich, O E; Zhitni?, N I; Chirkin, V I; Ivashenko, M V
1989-01-01
Principal block-diagram and characteristics of devices recording the parameters of periodontal muscular reflex in humans are presented. Twenty healthy volunteers aged 20 to 30 years with full dentition and normal occlusion and temporomandibular articulations unchanged were studied. Parameters of periodontal muscular reflex showed no bilateral asymmetry. Temporal muscles displayed 15 +/- 0.87 s latencies, masseters 13 +/- 0.8 latencies. Silent periods in temporal muscles were 22 +/- 0.89 ms and in masseters 24 +/- 0.75 ms. In patients with mandibular fractures the time of periodontal muscular reflex was increased up to 3-4-fold as compared to that in normal subjects. The indices of the reflex are clearly different in normal and pathological conditions. This technique is useful both in scientific and diagnostic purposes. PMID:2749808
Sustainable Development: Representing a Reflexive Modernity Inside the United Nations
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Dr. Gregory Borne
2010-01-01
Full Text Available This paper suggests that the discourse of sustainable development (SD within the United Nations (UN represents a paradigm shift from first/industrial modernity to a reflexive modernity. Reflexive modernity is defined by the changing nature of political structures in the face of globalised environmental risk, as well as a questioning of the hegemony of the scientific process as a basis for the development of humanity and the planet. SD is a concept that innately reflects these concerns, questioning normative assumptions. This paper will argue that the rise of SD in governance discourse is not only a catalyst for a reflexive modernity, but also is representative of a modernity that is already in a state of reflexivity. This proposition is examined by exploring the various ways that SD is utilised in the governance structure of the United Nations (UN.
Reflex Bronchospasm-Induced Acute Massive Pulmonary Collapse
Lee, San-chih; Lin, Yaw-shin; Lin, Kuo-juei; Wang, Min-heh
1988-01-01
Acute massive pulmonary collapse following reflex bronchospasm is described in a patient undergoing general anesthesia. The authors suggest that a chest radiograph should be taken as routine procedure after the onset of airway constriction during anesthesia.
Soleus H-reflex excitability during pedaling post-stroke
DEFF Research Database (Denmark)
Schindler-Ivens, Sheila; Brown, David A.
2008-01-01
A major contributor to impaired locomotion post-stroke is abnormal phasing of paretic muscle activity, but the mechanisms remain unclear. Previous studies have shown that, in the paretic limb of people post-stroke, Group Ia reflexes are abnormally elevated and fail to decrease in amplitude during locomotion. Hence, we hypothesized that inappropriate muscle phasing may be associated with enhanced transmission in the monosynaptic Group Ia afferent pathway. Soleus (SO) H-reflexes were used to examine transmission in the Group Ia afferent pathway to SO motor neurons during pedaling, a locomotor task in which abnormal muscle phasing is evident. Our hypothesis predicted that H-reflexes would be elevated during the flexion phase of pedaling where inappropriate SO activity occurs. H-reflexes were elicited in paretic (n = 13) and neurologically intact (NI, n = 26) individuals at 11 different positions in the pedaling cycle and during tonic plantar flexion at comparable limb positions and levels of SO EMG. In both groups, SO H-reflexes were smaller during pedaling as compared to matched tonic plantar flexion. In the NI group, but not the paretic group, SO H-reflex amplitude was significantly modulated across the pedaling cycle. H-reflexes were large during extension and small during flexion. Reduced H-reflex modulation post-stroke was associated with the level of neuromuscular impairment as indicated by Fugl-Meyer score. However, regardless of impairment level, stroke subjects displayed H-reflex suppression during the flexion phase of pedaling. After correcting for the level of background muscle activity, H-reflexes were found to be larger in paretic as compared to NI individuals, regardless of the phase of the pedaling cycle. We conclude that Group Ia afferent transmission is enhanced in the paretic SO of people post-stroke as compared to NI individuals. However, contrary to our hypothesis, enhanced transmission in the Group Ia monosynaptic spinal pathway is not specifically associated with extraneous extensor muscle activity during the flexion phase of pedaling and is unlikely to account for abnormal locomotor muscle phasing post-stroke. This result is important because it suggests that, despite the presence of hyperactive monosynaptic reflexes post-stroke, this impairment may not make an important contribution to abnormal locomotor muscle activity.
Muscle reflex in heart failure: the role of exercise training
HanjunWang
2012-01-01
Exercise evokes sympathetic activation and increases blood pressure and heart rate (HR). Two neural mechanisms that cause the exercise-induced increase in sympathetic discharge are central command and the exercise pressor reflex (EPR). The former suggests that a volitional signal emanating from central motor areas leads to increased sympathetic activation during exercise. The latter is a reflex originating in skeletal muscle which contributes significantly to the regulation of the cardiovascu...
The ecologic reflexivity in the context of hospital work
Silviamar Camponogara; Flavia Regina Souza Ramos; Ana Lucia Cardoso Kirchhof
2007-01-01
This article is about a thesis project, which aims to debate the relation between the hospital worker and the present ecologic problematic. The structuring of the object of study comes with the understanding that we live in a “reflexive” society (Giddens, 1997) and that, as social “actors” or characters we present manifestations related to this reflexivity. Also related to this, the ecologic problematic demands from all human beings a responsible behavior concerning the environment (J...
Nonlinear shunting model of the pupil light reflex.
Bressloff, P C; Wood, C V; Howarth, P A
1996-08-22
A leaky-integrator equation with shunting is introduced to represent processing at the retinal level as part of a system of delay-differential equations modelling the pupil light reflex. This system of equations exhibits the correct behaviour in response to monocular and binocular sinusoidal inputs. Understanding such behaviour can help to establish (non-invasively) the location and nature of nonlinearities in the reflex arc and how signals from the two eyes combine. PMID:8805832
Mechanical Characteristics of Reflex Durign Upright Posture in Paralyzed Subjects
Kim, Yongchul; Youm, Youngil; Lee, Bumsuk; Kim, Youngho; Choi, Hyeonki
The characteristics of flexor reflexes have been investigated in the previous studies with human subjects who were seated or supine position. However, researchers did not describe how the spinal circuits are used in different hip angles for paralyzed subjects, such as the standing position with walker or cane. In upright posture the compatibility between a flexor reflex of leg and body balance is a special problem for lower limb injured subjects. Therefore, the purpose of this study was to investigate the effects of hip angle change on the flexor reflex evoked in standing paralyzed subjects supported by walker. In this study, six spinal cord injured and four stroke subjects were recruited through the inpatient physical therapy clinics of Korea national rehabilitation hospital. A single axis electronic goniometer was mounted on the lateral side of the hip joint of the impaired limb to record movements in the sagittal plane at this joint. The electronic goniometer was connected to a data acquisition system, through amplifiers to a computer. Since subject' posture influenced characteristics of the flexion reflex response, the subjects were supported in an upright posture by the help of parallelogram walder. Two series of tests were performed on each leg. The first series of the tests investigated the influence of hip angle during stationary standing posture on flexion reflex response. The hip angle was adjusted by the foot plate. The second examined the effect of the voluntary action of subject on swing motion during the gait. The electrically induced flexion reflex simultaneously produced the flexion of the hip, knee and dorsiflexion of the ankle enabling the swing phase of walking. Form the experimental results we observed that the reflex response of hip joint was largerwith the hip in the extended position than in the flexed position during standing posture. Under voluntary movement on flexion reflex during gaint, the peak hip angle induced by stimulation was increased in spinal cord injury and stroke patients by subject' voluntary movement.
Management of the trigeminocardiac reflex: Facts and own experience
Arasho Belachew; Sandu Nora; Spiriev Toma; Prabhakar Hemanshu; Schaller Bernhard
2009-01-01
The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hyper-motility during stimulation of any of the sensory branches of the trigeminal nerve. The proposed mechanism for the development of TCR is-the sensory nerve endings of the trigeminal nerve send neuronal signals via the Gasserian ganglion to the sensory nucleus of the trigeminal nerve, forming the afferent pathway of the reflex arc. It has been demonst...
Trigeminocardiac Reflex during Maxillary Reconstruction Surgery: A Case Report
Mayank Kulshrestha; Sahil Kapur; Kapadia, Col M.
2014-01-01
Systemic hypotension, cardiac dysrhythmia especially bradycardia, apnoea, and gastric hypermotility occurring presumably after stimulation of any of the sensory branches of trigeminal nerve is coined as trigeminocardiac reflex (TCR). It has been described to occur in various surgeries like cerebello-pontine angle and pituitary fossa surgeries. Such bradycardic reflex responses have also been observed during maxillofacial surgeries. The TCR presents as a challenge to both the Anaesthesiologis...
Coronary Spasm in Neurosurgical Patients and Role of Trigeminocardiac Reflex
Tumul Chowdhury; Cyrill Meuwly; Nora Sandu; Cappellani, Ronald B.; Bernhard Schaller
2014-01-01
Background. Coronary artery spasm (CAS) is a rarely reported complication in neurosurgical patients and its main causative mechanism was attributed to vagal mediated responses. However, these may be the unusual manifestations of trigeminal cardiac reflex (TCR) which is a well established brain stem reflex observed in various neurosurgical patients. Methods and Results. In this review, we have searched for the case reports/papers related to intraoperative coronary spasm in neurosurgical patien...
Reflexive Water Management in Arid Regions: The Case of Iran
Balali, M. R.; Keulartz, F. W. J.; Korthals, M. J. J. A. A.
2012-01-01
To illuminate the problems and perspectives of water management in Iran and comparable (semi-) arid Middle East and North Africa (MENA) countries, three paradigms can be distinguished: the traditional, the industrial and the reflexive paradigm. Each paradigm is characterised by its key technical system, its main social institution and its ethico-religious framework. Iran seems to be in a state of transition from the 'hydraulic mission' of industrial modernity to a more reflexive approach to w...
HPLC analysis of closed, open, and reflex eye tear proteins
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Sitaramamma T
1998-01-01
Full Text Available Changes in the closed, open and reflex eye tear proteins of normal subjects were compared and analysed. Tear proteins were resolved by high-performance liquid chromatography (HPLC utilising both gel filtration (P-300 SW and reverse-phase (C-18 columns and the HPLC fractions were further analysed by sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE under reducing and non-reducing conditions. The protein composition of the closed-eye tear was significantly different from that of the open and reflex-eye tear. Secretory IgA (sIgA was the predominant protein in closed eye tears constituting 49% of the total protein compared to 11% in reflex tears, whereas lysozyme was the predominant protein (53% in reflex tears. Levels of lactoferrin, lipocalin and lysozyme were relatively constant in both open and reflex tears. HPLC profiles of the closed-eye tears, upon continuous stimulation of lacrimal glands indicated that sIgA was significantly reduced whereas lactoferrin, lipocalin, and lysozyme were significantly increased. These results indicate that the tear composition upon waking attains that of the open eye within 4 to 5 minutes, and upon continuous stimulation this reflects the reflex-eye tear composition. It also indicates that mechanisms responsible for changes in concentration of constitutive and regulated tear protein with stimulus can be studied successfully using non-invasive methods to collect human tears.
Compensatory adrenal growth - A neurally mediated reflex
Dallman, M. F.; Engeland, W. C.; Shinsako, J.
1976-01-01
The responses of young rats to left adrenalectomy or left adrenal manipulation were compared to surgical sham adrenalectomy in which adrenals were observed but not touched. At 12 h right adrenal wet weight, dry weight, DNA, RNA, and protein content were increased (P less than 0.05) after the first two operations. Left adrenal manipulation resulted in increased right adrenal weight at 12 h but no change in left adrenal weight. Sequential manipulation of the left adrenal at time 0 and the right adrenal at 12 h resulted in an enlarged right adrenal at 12 h (P less than 0.01), and an enlarged left adrenal at 24 h (P less than 0.05), showing that the manipulated gland was capable of response. Bilateral adrenal manipulation of the adrenal glands resulted in bilateral enlargement of 12 h (P less than 0.01). Taken together with previous results, these findings strongly suggest that compensatory adrenal growth is a neurally mediated reflex.
Reflex anuria affecting both kidneys following hysterectomy
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Gholyaf Mahmoud
2009-01-01
Full Text Available In situations when there is unilateral ureteral obstruction, the contralateral kidney retains its normal function. In rare instances however, it has been reported that unilateral ureteral obstruction can lead to reflex anuria (RA and acute renal failure (ARF. Even more unusually, RA with ARF can occur without organic obstruction due to ureteric manipulation during pelvic surgery. We report a 78- year-old woman, who underwent hysterectomy because of endometrial carcinoma. She developed ARF evidenced by anuria of 120-hours duration, and gradual rise of serum creatinine levels to 11.8 mg/dL on the fifth day after hysterectomy. Ultrasound study of the urinary tract revealed bilateral moderate hydronephrosis. Detailed evaluation did not reveal any organic obstruc-tion. She was managed with hemodialysis, control of hypertension and correction of fluid and elec-trolyte imbalances. By the sixth day, diuresis was established, and the blood urea and serum crea-tinine levels decreased to normal by the sixteenth day. The patient was finally discharged on the eighteenth day. Our case suggests that urologists and nephrologists should consider RA as one of the causes of anuria and ARF.
Determination of trigeminocardiac reflex during rhinoplasty.
Yorgancilar, E; Gun, R; Yildirim, M; Bakir, S; Akkus, Z; Topcu, I
2012-03-01
In most rhinoplasty procedures, osteotomies are usually required. The osteotomy areas are innervated by sensory branches of the trigeminal nerve. The trigeminocardiac reflex (TCR) is clinically defined as the sudden onset of parasympathetic activity during stimulation of the trigeminal nerve. When an osteotomy is performed or external pressure is applied over the nasal bone, the infraorbital nerve may send signals via this nerve. The aim of this prospective study is to determine the blood pressure changes and occurrence of TCR during rhinoplasty. one hundred and eight patients were enrolled into the study. Lidocaine and adrenaline combination (LAC) was injected only into the left lateral osteotomy sites. All patients underwent median, right-side, then left-side lateral osteotomies and nasal pyramid infracture. The haemodynamic changes were recorded. A 10% or more decrease in the heart rate from baseline was considered a TCR. TCR was detected in nine patients following lateral osteotomies and nasal pyramid infracture procedures (8.3%). The authors determined that LAC injection prior to osteotomy did not prevent TCR. Manipulation at or near the infraorbital nerve during rhinoplasty may cause TCR, even if local anaesthetic infiltration is used. PMID:22240287
Impaired Sacculocollic Reflex in Lateral Medullary Infarction
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SeonhyeKim
2011-02-01
Full Text Available Objective: The aim of this study was to determine saccular dysfunction by measuring cervical vestibular-evoked myogenic potentials (cVEMP and to correlate abnormality of cVEMP with results of other vestibular function tests in lateral medullary infarction (LMI. Methods: We recorded cVEMP in 21 patients with LMI documented on MRI. cVEMP was induced by a short tone burst and was recorded in contracting sternocleidomastoid muscle while patients turned their heads forcefully to the contralateral side against resistance. Patients also underwent video-oculographic recording of spontaneous, gaze-evoked and head-shaking (HSN nystagmus, evaluation of ocular tilt reaction (OTR, measurement of the subjective visual vertical (SVV tilt, bithermal caloric tests and audiometry. Results: Nine patients (43% showed abnormal cVEMP, unilateral in seven and bilateral in two. The cVEMP abnormalities included decreased p13-n23 amplitude in four, delayed p13/n23 responses in five, and both decreased and delayed responses in two. The abnormal cVEMP was ipsilesional in five, contralesional in two, and bilateral in two. The prevalence of OTR/SVV tilt, spontaneous nystagmus, and HSN did not differ between the patients with normal and abnormal cVEMP. Conclusion: cVEMP was abnormal in approximately half of the patients with LMI. The abnormal cVEMP indicates damage to the descending sacculocollic reflex pathway or disruption of commissural modulation between the vestibular nuclei.
Fiber Structure and Local Coordinates for the Teichmueller Space of a Bordered Riemann Surface
Radnell, David
2009-01-01
We show that the infinite-dimensional Teichmueller space of a Riemann surface whose boundary consists of n closed curves is a holomorphic fiber space over the Teichmueller space of n-punctured surfaces. Each fiber is a complex Banach manifold modeled on a two-dimensional extension of the universal Teichmueller space. The local model of the fiber, together with the coordinates from internal Schiffer variation, provides new holomorphic local coordinates for the infinite-dimensional Teichmueller space.
The clinical grouping of skin reflexes in different forms of cerebral palsy.
Vlach, V
1991-01-01
Previous studies in healthy infants and children showed the gradual disappearance of skin reflexes at specific times: distal skin reflexes disappeared early while trunk-dorsal reflexes disappeared later. In this study the same twenty-eight skin reflexes on the extremities and the trunk were examined in one hundred and thirty-three cerebral palsy patients aged from 1.3 to 18 years. Some of these reflexes persisted longer and were more intense than in healthy children. In spastic forms of cerebral palsy they were mainly the distal skin reflexes that persisted longer, while in the dyskinetic form longer persistence of trunk-dorsal reflexes and stronger abdominal reflexes were found. In the cerebellar form only very low persistence of distal reflexes was ascertained. PMID:2055549
Trigeminocardiac reflex. A clinical phenomenon or a new physiological entity?
Schaller, B
2004-06-01
The trigemino-cardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. The sensory nerve endings of the trigeminal nerve send neuronal signals via the Gasserian ganglion to the sensory nucleus of the trigeminal nerve, forming the afferent pathway of the reflex arc. This afferent pathway continues along the short internuncial nerve fibers in the reticular formatio to connect with the efferent pathway in the motor nucleus of the vagus nerve. Clinically, the trigemino-cardiac reflex has been reported to occur during craniofacial surgery, balloon-compression rhizolysis of the trigeminal ganglion, and tumor resection in the cerebellopontine angle. Apart from the few clinical reports, the physiological function of this brainstem-reflex has not yet been fully explored. From experimental findings, it may be suggested that the trigemino-cardiac reflex represents an expression of a central neurogenic reflex leading to rapid cerebrovascular vasodilatation generated from excitation of oxygen-sensitive neurons in the rostral ventrolateral medulla oblongata. By this physiological response, the adjustments of the systemic and cerebral circulations are initiated to divert blood to the brain or to increase blood flow within it. As it is generally accepted that the diving reflex and ischemic tolerance appear to involve at least partially similar physiological mechanisms, the existence of such endogenous neuroprotective strategies may extend the actually known clinical appearance of the TCR and include the prevention of other potentially brain injury states as well. This may be in line with the suggestion that the TCR is a physiological, but not a pathophysiological entity. PMID:15311339
Regional cerebral perfusion in cardiovascular reflex syncope
International Nuclear Information System (INIS)
Little is known about the regional cerebral perfusion in subjects with presyncope or syncope, and the impact that autonomic nervous dysfunction has on it. Seven subjects with cardiovascular vasodepressor reflex syncope were studied. A baseline test was performed with the patients standing in the 70 upright position, while the passive head-up tilt table test with and without isoprenaline infusion was employed for provocation. Regional cerebral perfusion was assessed by means of single-photon emission tomography with technetium-99m labelled V-oxo-1,2-N,N1-ethylenedylbis-l-cysteine diethylester (baseline, and during blood pressure decline in the provocation test) and the autonomic nervous function by means of spectral analysis of heart rate variability (baseline, and before blood pressure decline in the provocation test). Every subject showed an abrupt decline in blood pressure in the provocation test (five with presyncope and two with syncope). The systolic and diastolic blood pressures decreased significantly (P<0.001) between the baseline and the provocation study time points (radiopharmaceutical injection and lowest systolic blood pressure). Mean cerebral perfusion as average count densities decreased upon provocation as compared with baseline (190±63 vs 307±90 counts/voxel, respectively, P=0.013). Hypoperfusion was most pronounced in the frontal lobe. These results suggest that cerebral perfusion decreases markedly during presyncope or syncope with systy during presyncope or syncope with systemic blood pressure decline in subjects with cardiovascular vasodepressor syncope. Furthermore, the autonomic nervous function remains unchanged before the systemic blood pressure decline. (orig.). With 3 figs., 2 tabs
Measure, integration and function spaces
Swartz, Charles
1994-01-01
This text contains a basic introduction to the abstract measure theory and the Lebesgue integral. Most of the standard topics in the measure and integration theory are discussed. In addition, topics on the Hewitt-Yosida decomposition, the Nikodym and Vitali-Hahn-Saks theorems and material on finitely additive set functions not contained in standard texts are explored. There is an introductory section on functional analysis, including the three basic principles, which is used to discuss many of the classic Banach spaces of functions and their duals. There is also a chapter on Hilbert space and
Fixed point theorems in modular spaces
Elaidi, Hanebaly
2005-01-01
By iterative techniques,we present two fixed point theorems, whose modular formulations are relatively close to the Banach's fixed point theorem in the normed spaces.The first result concerns the fixed point of the strongly contraction mappings.The second result deals with the fixed point of the strict contraction mappings where the modular satisfies the delta-condition. For the nonexpansive mappings,where the modular satisfies the regular growth condition,we present a fixe...
Stable Ranks, K-Groups and Witt Groups of some Banach and C-star Algebras
Badea, C.
1999-01-01
We show that certain dense and spectral invariant subalgebras of a $C^*$-algebra have the same bilateral Bass stable rank. This is a partial answer for (a version of) an open problem raised by R.G. Swan. Then, for certain Banach algebras, we indicate when the homotopy groups $\\pi_{i}(GL_{n}(A))$ stabilize for large $n$. This is an improvement of a result due to G. Corach and A. Larotonda. Using some results due to M. Karoubi, we show the isomorphism of the Witt group of a sy...
The Prepared Reflex: Behavioral and Subjective Flanker Interference Effects
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Pin-Wei Chen
2014-11-01
Full Text Available One can easily learn to associate a motor response to a given sensory stimulus. This linking of stimuli to responses (“S-R links,” for short may be learned through verbal instruction or through extensive training. The former has been characterized as something akin to the acquisition of a “prepared reflex.” Recently, it has been demonstrated that, in the flanker paradigm, S-R links acquired through prepared reflexes can yield the interference effects found with the traditional versions of this task, which normally include training. In a fully within-subjects paradigm, we replicated this current research and extended it, by including (a contrasts between all traditional flanker conditions (including response interference and perceptual interference and (b trial-by-trial subjective measures of performance (i.e., “urges to err”. The behavioral and subjective effects found with prepared reflexes resembled those found following normal S-R link acquisition. The theoretical implications of this finding are discussed.
Faroese long-distance reflexives face off against Icelandic long-distance reflexives
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Tania E. Strahan
2009-01-01
Full Text Available Long-distance reflexives (LDRs in Faroese are often compared to those in Icelandic, and are even considered to have the same distribution (Thráinsson et al., 2004. In this paper I evaluate the extent to which this is true. The results from recent fieldwork show that there are clear differences between the LDR in the two closely related languages, in particular that Faroese speakers often reject LDR sentences that contain a non-third person, and that Faroese LDR is often completely acceptable out of a non-complement clause. In addition, initial findings suggest that there may be dialectal variation with respect to at least these two aspects of LDR in Faroese.
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2009-02-01
Full Text Available We give conditions for the parabolic evolution operator to be analytic with respect to a coefficient operator. We also show that the solution of a homogeneous parabolic evolution equation is analytic with respect to the coefficient operator and to the initial data. We apply our results to example that can not be studied by the standard methods.
Asymptotic behaviour of solutions of nonlinear delay difference equations in Banach spaces
Anna Kisiolek; Ireneusz Kubiaczyk
2005-01-01
We consider the second-order nonlinear difference equations of the form ÃŽÂ”(rnÃ¢ÂˆÂ’1ÃŽÂ”xnÃ¢ÂˆÂ’1)+pnf(xnÃ¢ÂˆÂ’k)=hn. We show that there exists a solution (xn), which possesses the asymptotic behaviour Ã¢Â€Â–xnÃ¢ÂˆÂ’aÃ¢ÂˆÂ‘j=0nÃ¢ÂˆÂ’1(1/rj)+bÃ¢Â€Â–=o(1), a,bÃ¢ÂˆÂˆÃ¢Â„Â. In this paper, we extend the results of Agarwal (1992), Dawidowski et al. (2001), Drozdowicz and Popenda (1987), M. Migda (2001), and M. Migda...
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Zhiqun Xue
2008-03-01
Full Text Available The purpose of this paper is to compare convergence speed of the Picard and Mann iterations on one hand, Krasnoselskij and Ishikawa iterations on the other hand, for the class of Zamfirescu operators. The results improve corresponding results of (Berinde 2004 and (Babu and Vara Prasad 2006.
Xue Zhiqun
2008-01-01
The purpose of this paper is to compare convergence speed of the Picard and Mann iterations on one hand, Krasnoselskij and Ishikawa iterations on the other hand, for the class of Zamfirescu operators. The results improve corresponding results of (Berinde 2004) and (Babu and Vara Prasad 2006).
Zajicek, Ludek
2013-01-01
The classical Denjoy-Young-Saks theorem on Dini derivatives of arbitrary functions $f: \\R \\to \\R$ was extended by U.S. Haslam-Jones (1932) and A.J. Ward (1935) to arbitrary functions on $\\R^2$. This extension gives the strongest relation among upper and lower Hadamard directional derivatives $f^+_H (x,v)$, $f^-_H (x,v)$ ($v \\in X$) which holds almost everywhere for an arbitrary function $f:\\R^2\\to \\R$. Our main result extends the theorem of Haslam-Jones and Ward to functions...
Halpern-type Iterations for Strong Relatively Nonexpansive Multi-valued Mappings in Banach Spaces
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Fuhai ZHAO
2012-05-01
Full Text Available
In this paper, an iterative sequence for strong relatively nonexpansive multi-valued mapping by modifying Halpern’s iterations is introduced, and then some strong convergence theorems are proved. At the end of the paper some applications are given also.
Key words Multi-valued mapping; Strong relatively nonexpansive; Fixed point; Iterative sequence; Normalized duality mapping
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J. K. Kim
2008-10-01
Full Text Available In this paper, a new implicit iteration process with errors for finite families of strictly asymptotically pseudocontractive mappings and nonexpansive mappings is introduced. By using the iterative process, some strong convergence theorems to approximating a common fixed point of strictly asymptotically pseudocontractive mappings and nonexpansive mappings are proved. The results presented in the paper are new which extend and improve some recent results of Osilike et al. (2007, Liu (1996, Osilike (2004, Su and Li (2006, Gu (2007, Xu and Ori (2001.
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Chang Shih-sen
2008-01-01
Full Text Available Abstract In this paper, a new implicit iteration process with errors for finite families of strictly asymptotically pseudocontractive mappings and nonexpansive mappings is introduced. By using the iterative process, some strong convergence theorems to approximating a common fixed point of strictly asymptotically pseudocontractive mappings and nonexpansive mappings are proved. The results presented in the paper are new which extend and improve some recent results of Osilike et al. (2007, Liu (1996, Osilike (2004, Su and Li (2006, Gu (2007, Xu and Ori (2001.
Mujica, J
1985-01-01
Problems arising from the study of holomorphic continuation and holomorphic approximation have been central in the development of complex analysis in finitely many variables, and constitute one of the most promising lines of research in infinite dimensional complex analysis. This book presents a unified view of these topics in both finite and infinite dimensions.
Pengyu Chen; Jia Mu
2010-01-01
We use a monotone iterative method in the presence of lower and upper solutions to discuss the existence and uniqueness of mild solutions for the initial value problem $$displaylines{ u'(t)+Au(t)= f(t,u(t),Tu(t)),quad tin J,; t eq t_k,cr Delta u |_{t=t_k}=I_k(u(t_k)) ,quad k=1,2,dots ,m,cr u(0)=x_0, }$$ where $A:D(A)subset Eo E$ is a closed linear operator and $-A$ generates a strongly continuous semigroup $T(t)(tgeq 0)$ in $E$. Under wide monotonicity conditions and the non-compac...
Integral representations of cylindrical local martingales in every separable Banach space.
Czech Academy of Sciences Publication Activity Database
Ondreját, Martin
2007-01-01
Ro?. 10, ?. 3 (2007), s. 1-15. ISSN 0219-0257 R&D Projects: GA ?R GA201/04/0750 Institutional research plan: CEZ:AV0Z10190503 Keywords : brownian representation Subject RIV: BA - General Mathematics Impact factor: 0.689, year: 2007
A New One-Step Iterative Process for Common Fixed Points in Banach Spaces
Directory of Open Access Journals (Sweden)
Jong Kyu Kim
2008-12-01
Full Text Available We introduce a new one-step iterative process and use it to approximate the common fixed points of two asymptotically nonexpansive mappings through some weak and strong convergence theorems. Our process is computationally simpler than the processes currently being used in literature for the purpose.
A New One-Step Iterative Process for Common Fixed Points in Banach Spaces
Khan SafeerHussain; Kim JongKyu; Abbas Mujahid
2008-01-01
Abstract We introduce a new one-step iterative process and use it to approximate the common fixed points of two asymptotically nonexpansive mappings through some weak and strong convergence theorems. Our process is computationally simpler than the processes currently being used in literature for the purpose.
A New One-Step Iterative Process for Common Fixed Points in Banach Spaces
Directory of Open Access Journals (Sweden)
Khan SafeerHussain
2008-01-01
Full Text Available Abstract We introduce a new one-step iterative process and use it to approximate the common fixed points of two asymptotically nonexpansive mappings through some weak and strong convergence theorems. Our process is computationally simpler than the processes currently being used in literature for the purpose.
"A case of self-induced reflex epilepsy "
Moatamedi M; Banki A; Sahraian M "
2000-01-01
The term reflex epilepsy in reserved for a small subgroup o seizures that occur regularly in response to specific stimuli. Our patient is a 20- year old male, who had pleasure, euphoria, loss of conciousness and generalized tonic- clonic convulstion when he watched TV since ten years. During puberty the patient that self-induced reflex epilepsy with photic stimulation, when watching TV or looking at sun and with had moving in front of his eyes to produce flickers. The patient first had sex pl...
Standardisation of the electrical elicitation of the human flexor reflex.
Tøorring, J.; Pedersen, E.; Klemar, B.
1981-01-01
The threshold and latency of the human flexor reflex were recorded by different kinds of electrical stimuli in order to find the optimal stimulus, defined as the lowest amount of currency and the shortest possible duration. Stimulation was given over the posterior tibial nerve of the foot. The reflex response was recorded from the tibialis anterior muscle and the number and duration of the pulses and the inter-phase interval were varied. A train of five square wave pulses with a duration of 0...
Startle reflex habituation in functional psychoses: a controlled study.
Bolino, F; Manna, V; Di Cicco, L; Di Michele, V; Daneluzzo, E; Rossi, A; Casacchia, M
1992-10-12
The habituation of the startle reflex in a paradigm using electrical stimulation was studied in 17 psychotic patients and 18 healthy controls. The magnitude of the R2 component of the blink reflex differed between the groups (ANOVA, F = 5.81; P = 0.022) and during the course of trials (F = 25.72; P < 0.0001). Furthermore a statistically significant interaction of diagnosis x trials (F = 3.34; P = 0.022) emerged suggesting that an impairment in habituation of startle is present in patients but not in healthy controls despite a comparable reactivity. PMID:1465206
Primary reflex persistence in children with partial hearing.
Livingstone, Nuala; McPhillips, Martin
2014-01-01
Persistence of the asymmetrical tonic neck reflex (ATNR) was examined in children with partial hearing (aged 6-12 years). Core literacy skills were also assessed. Three groups of children were selected from three schools with special units for children with partial hearing. All children completed an upright ATNR test protocol and standardized tests of reading and spelling. Children with partial hearing had significant levels of ATNR persistence, and significant reading and spelling difficulties. The findings suggest that persistence of an early sub-cortical reflex system may be associated with some of the motor and cognitive difficulties experienced by children with partial hearing. PMID:24742313
Mirroring Meetings, Mirroring Media: The Microphysics of Reflexivity
Forna?s, Johan
1994-01-01
There is today a growing reflexivity in individual and collective identity constructions. Identities are always formed in relation to others and through symbolic structures, but this process has been more mobilized, differentiated, focused and problematized in late modernity – the most recent phase of the process of modernization.[i] This is true for daily life as well as for research. Reflexivity has in various ways been an important theme within psychoanaly...
Trigeminocardiac Reflex during Maxillary Reconstruction Surgery: A Case Report
Directory of Open Access Journals (Sweden)
Mayank Kulshrestha
2014-03-01
Full Text Available Systemic hypotension, cardiac dysrhythmia especially bradycardia, apnoea, and gastric hypermotility occurring presumably after stimulation of any of the sensory branches of trigeminal nerve is coined as trigeminocardiac reflex (TCR. It has been described to occur in various surgeries like cerebello-pontine angle and pituitary fossa surgeries. Such bradycardic reflex responses have also been observed during maxillofacial surgeries. The TCR presents as a challenge to both the Anaesthesiologist and the Surgeon in view of its varied presentations, diagnosis, prevention and appropriate management.
Stably reflexive modules and a Lemma of Knudsen
Ile, Runar
2011-01-01
In his fundamental work on the stack of stable n-pointed genus g curves, Finn F. Knudsen introduced the concept of a stably reflexive module in order to prove a key technical lemma. We propose an alternative definition and generalise the results in the appendix to his article. Then we give a `coordinate free' generalisation of his lemma and also generalise a construction used in Knudsen's proof concerning versal families of pointed algebras. In addition we prove approximation theorems generalising Cohen-Macaulay approximation with stably reflexive modules in flat families.
Directory of Open Access Journals (Sweden)
Kim Knott
2005-12-01
Full Text Available Two issues are explored in this article: the way in which "space" has been theorized in relation to the "sacred", and the use of contemporary cultural and social theories of space in the development of a methodology for locating religion in places, objects, bodies and groups open to investigation. After a brief recollection of the spatial contributions of van der Leeuw and Eliade, attention is given to the theoretical and methodological insights of Jonathan Z. Smith, Veikko Anttonen, and Kim Knott.
Fixed Points, Inner Product Spaces, and Functional Equations
Choonkil Park
2010-01-01
Rassias introduced the following equality , , for a fixed integer . Let be real vector spaces. It is shown that, if a mapping satisfies the following functional equation for all with , which is defined by the above equality, then the mapping is realized as the sum of an additive mapping and a quadratic mapping. Using the fixed point method, we prove the generalized Hyers-Ulam stability of the above functional equation in real Banach spaces.
Snakes and articulated arms in an Hilbert space
Pelletier, Fernand
2011-01-01
The purpose of this paper is to give an illustration of results on integrability of distributions and orbits of vector fields on Banach manifolds obtained in [Pe] and [LaPe]. Using arguments and results of these papers, in the context of a separable Hilbert space, we give a generalization of a Theorem of accessibility contained in [Ha], [Ro] and proved for a finite dimensional Hilbert space
Modulation of flexion reflex induced by hip angle changes in human spinal cord injury
Knikou, Maria; Kay, Elizabeth; Rymer, William Zev
2005-01-01
The flexion reflex can be elicited via stimulation of skin, muscle, and high-threshold afferents inducing a generalized flexion of the limb. In spinalized animal models this reflex is quite prominent and is strongly modulated by actions of hip proprioceptors. However, analogous actions on the flexion reflex in spinal cord injured (SCI) humans have not yet been examined. In this study, we investigated the effects of imposed static hip angle changes on the flexion reflex in ten motor incomplete...
Klass, Malgorzata; Baudry, Ste?phane; Duchateau, Jacques
2011-01-01
During voluntary contractions, motor neurone activity is modulated by descending input and sensory feedback. Impaired excitatory afferent feedback with ageing may, therefore, alter motor control. This study investigated the age-related changes in afferent feedback through the recording of reflex responses during voluntary muscle activation. Short- and long-latency components of the stretch reflex and Hoffmann reflex (H-reflex) were recorded during voluntary contractions (10% of maximal volunt...
Spiriev Toma; Tzekov Christo; Laleva Lili; Kostadinova Christina; Kondoff Slavomir; Sandu Nora; Schaller Bernhard
2012-01-01
Abstract Introduction Trigeminocardiac reflex is a well-known phenomenon in neurosurgery, craniofacial surgery, ophthalmology and interventional neuroradiology. Even though the trigeminocardiac reflex has become an important factor in skull base surgery and neurosurgery, the central form of trigeminocardiac reflex has only been described in adult subpopulations until now. Case presentation We present a clear form of repetitive trigeminocardiac reflex expressed during revision surgery of a gia...
Embeddings of Sobolev-type spaces into generalized Hölder spaces involving k-modulus of smoothness.
Czech Academy of Sciences Publication Activity Database
Gogatishvili, Amiran; Moura, S.; Neves, J. S.; Opic, B.
2015-01-01
Ro?. 194, ?. 2 (2015), s. 425-450. ISSN 0373-3114 R&D Projects: GA ?R GA13-14743S Institutional support: RVO:67985840 Keywords : rearrangement-invariant Banach function space * modulus of smoothness * distributional gradient Subject RIV: BA - General Mathematics Impact factor: 0.909, year: 2013 http://link.springer.com/article/10.1007/s10231-013-0383-1
ARENS REGULARITY OF SOME BILINEAR MAPS
Scientific Electronic Library Online (English)
M. ESHAGHI, GORDJI.
2009-05-01
Full Text Available Let H be a Hilbert space. we show that the following statements are equivalent: (a) B(H) is finite dimension, (b) every left Banach module action l : B(H)×H ? H, is Arens regular (c) every bilinear map f : B(H)*? B(H) is Arens regular. Indeed we show that a Banach space X is reflexive if and only if [...] every bilinear map f : X* × X ? X* is Arens regular.
Coorbit description and atomic decomposition of Besov spaces
Christensen, Jens Gerlach; Olafsson, Gestur
2011-01-01
Function spaces are central topic in analysis. Often those spaces and related analysis involves symmetries in form of an action of a Lie group. Coorbit theory as introduced by Feichtinger and Gr\\"ochenig and then later extended in [3] gives a unified method to construct Banach spaces of functions based on representations of Lie groups. In this article we identify the homogeneous Besov spaces on stratified Lie groups introduced in [13] as coorbit spaces in the sense of [3] and use this to derive atomic decompositions for the Besov spaces.
Gelfand and Kolmogorov numbers of Sobolev embeddings of weighted function spaces II
Zhang, Shun
2011-01-01
We determine the sharp asymptotic degree of the Gelfand and Kolmogorov numbers of compact embeddings between weighted function spaces of Besov and Triebel-Lizorkin type with polynomial weights in the non-limiting case. This complements our previous results in the context of the quasi-Banach setting, $0 < p, q \\le \\infty$. In addition the comparisons with corresponding approximation numbers are made.
Liu, Xiaoji; Qin, Xiaolan
2015-01-01
We investigate additive properties of the generalized Drazin inverse in a Banach algebra A. We find explicit expressions for the generalized Drazin inverse of the sum a + b, under new conditions on a, b ? A. As an application we give some new representations for the generalized Drazin inverse of an operator matrix. PMID:25729767
Analysis of the mechanism of interoceptive reflexes in altitude meteorism
Chirkin, M. D.
1973-01-01
Mechanisms of interoceptor reflexes during high altitude meteorisms are analyzed. The effects of pharmaceutical preparations on these mechanisms are discussed in detail, together with the EKG findings pertinent to these mechanisms and the conditions associated with them under the effect of extremal actions. Both respiratory and circulatory manifestations in the major organs (hollow organs) are considered.
[Acupuncture reflex therapy in the treatment of coccygodynia].
Gataullin, I G; Samitov, O Sh
1989-02-01
A complex of measures including physiotherapy, procaine-alcohol blockades, and massage of the coccyx and muscles of the pelvic floor were used in the treatment of 37 patients. Acupuncture reflex therapy was applied in addition in 24 patients. The complex method led to stable recovery of most of the patients. PMID:2709719
Processing Reflexives and Pronouns in Picture Noun Phrase
Runner, Jeffrey T.; Sussman, Rachel S.; Tanenhaus, Michael K.
2006-01-01
Binding theory (e.g., Chomsky, 1981) has played a central role in both syntactic theory and models of language processing. Its constraints are designed to predict that the referential domains of pronouns and reflexives are nonoverlapping, that is, are complementary; these constraints are also thought to play a role in online reference resolution.…
Experimental Optimization of a reflex triode virtual cathode oscillator
International Nuclear Information System (INIS)
Experimental findings on a high power Reflex Triode Virtual Cathode Oscillator (Vircator) are reported. The performance of a vircator are modified with the inclusion of reflecting strips. Motivation for this technique was driven by success of reflector inclusion to a coaxial vircator. A parametric experimental study was performed to optimize the performance of this geometry
Reflex sympathetic dystrophy/complex regional pain syndrome.
Gann, Charlotte
2008-02-01
Occupational health nurses are usually the first to assess workers with reflex sympathetic dystrophy/complex regional pain syndrome. Therefore, they must be aware of the signs and symptoms, implications for lost time, and higher incidence of disability related to this disorder. PMID:18306652
Primitive reflexes and the determination of fetal presentation at birth.
Bartlett, D; Piper, M; Okun, N; Byrne, P; Watt, J
1997-05-28
Ninety term breech-presenting singletons with birth weights greater than 2500 g and no congenital anomalies were matched with similar cephalic-presenting infants on gender and mode of delivery (n = 180). Thirteen primitive reflexes were examined at birth, 6 weeks and 3 and 5 months. No significant differences in the intensity of the asymmetrical tonic neck, symmetrical tonic neck, positive support tonic labyrinthine (prone and supine), segmental rolling (head-on-body and body-on-body), Galant, Moro, upper and lower extremity grasp, lower extremity placing and stepping reflexes were observed between these two groups of infants. Infants delivered vaginally, regardless of presentation, had weaker Moro reflexes at 5 months than infants delivered by cesarean section. The popular notion that precursors to early motor behaviors, such as the placing and stepping reflexes, are determinants of fetal presentation at the end of pregnancy is not supported by these results. Instead, spontaneously generated active whole body movements may be more significant influences of fetal orientation at the time of birth. PMID:9154417
Conducting Systematic Review in Education: A Reflexive Narrative
Nind, Melanie
2006-01-01
The evaluation of systematic review as part of the evidence-based or evidence-informed practice movement is a dominant theme in current debates in educational research. This article contributes to the debate by offering a personal, reflexive narrative on the process of doing systematic review, relating some of the arguments regarding the merits…
A reflexing electron microwave amplifier for rf particle accelerator applications
International Nuclear Information System (INIS)
The evolution of rf-accelerator technology toward high-power, high-current, low-emittance beams produces an ever-increasing demand for efficient, very high power microwave power sources. The present klystron technology has performed very well but is not expected to produce reliable gigawatt peak-power units in the 1- to 10-GHz regime. Further major advancements must involve other types of sources. The reflexing-electron class of sources can produce microwave powers at the gigawatt level and has demonstrated operation from 800-MHz to 40-GHz. The pulse length appears to be limited by diode closure, and reflexing-electron devices have been operated in a repetitively pulsed mode. A design is presented for a reflexing electron microwave amplifier that is frequency and phase locked. In this design, the generated microwave power can be efficiently coupled to one or several accelerator loads. Frequency and phase-locking capability may permit parallel-source operation for higher power. The low-frequency (500-MHz to 10-GHz) operation at very high power required by present and proposed microwave particle accelerators makes an amplifier, based on reflexing electron phenomena, a candidate for the development of new accelerator power sources. (author)
GlueAPI joining REFLEX and CometOS
Siegemund, Gerry; Lohs, Stefan
2013-01-01
Präsentation der glueAPI, einer API um CometOS und REFLEX, Betriebssysteme für drahtlose Sensornetze, zu koppeln. Detaillierte Beschreibungen wie auch Beispiele werden zur Verfügung gestellt. Drahtlose Sensornetzwerke (WSN) wurden für viele verschiedene Aufgaben in unterschiedlichsten Umgebungen entworfen. Betriebssysteme für Sensorknoten, den Komponenten von WSNs, gibt es in diversen Formen, von unterschiedlichen Anbietern, Universitäten, oder Privatpersonen. Die GlueAPI ist ein...
Spinal reflex properties in the long term after stroke.
Groenewegen, Jan S; de Groot, Jurriaan H; Schouten, Alfred C; Maier, Andrea B; Arendzen, J Hans; Meskers, Carel G M
2012-04-01
In the long term after stroke, secondary functional deterioration may be observed while patients also get older. Possible underlying mechanisms are largely unknown. We aimed to assess neuromuscular degeneration represented by alterations in peripheral reflex loop characteristics as a function of follow-up time after stroke, controlled for age. Twenty-one stroke survivors within a small age range (62-67 years) but large variance in follow-up time after stroke (1-15 years) and both five age matched (59-62 years) and young subjects (28-36 years) participated. Short and long latency reflexes evoked by ramp and hold stretches were identified from EMG traces of the m. flexor carpi radialis. Short latency reflex onset time was not enhanced (mean difference 1.6ms compared to age matched controls) and did not relate to follow-up time after stroke (p=0.81). Young controls showed significantly lower reflex delay times (mean difference 7.2ms with respect to older subjects, p=0.009). No evidence was found for peripheral neuromuscular deterioration as a function of follow up time after stroke. Functional deterioration as a result of ageing of stroke patients that may interact with post stroke follow-up time is of further interest. PMID:22196888
Postoperative seizure outcome after corpus callosotomy in reflex epilepsy.
Kwan, S Y; Wong, T T; Chang, K P; Yang, T F; Lee, Y C; Guo, W Y; Su, M S
2000-03-01
Flickering light and color patterns, reading, language, movement, decision making, eating, tapping and touching, hot water immersion and auditory stimulation can induce seizures in some epileptic patients. These are known as the "reflex epilepsies". The mechanism of reflex epilepsy is not clear. Recently, we performed anterior two-thirds corpus callosotomies in two reflex epilepsy patients (ages 12 and 14 years), with follow-up for more than three years. Patient 1 had Lennox-Gastaut syndrome with auditory-induced generalized atonic or tonic seizures (startle epilepsy), which decreased by 60% after callosotomy. Patient 2 had Lennox-Gastaut syndrome with somatosensory-induced generalized tonic seizures (tap epilepsy). He was seizure-free for one year immediately after callosotomy, but his seizures recurred with the same degree and frequency as before surgery. The nonsignificant postoperative seizure outcome suggests that the corpus callosum only plays a partial role in seizure generation. Our report also discusses the possible mechanisms of generation of reflex seizures. PMID:10746422
Power from Switching across Netdoms through Reflexive and Indexical Language.
Directory of Open Access Journals (Sweden)
Fontdevila, Jorge
2010-06-01
Full Text Available In differentiated societies with far-reaching yet fragmented social networks, the ability to manage pervasive ambiguity is crucial to navigate domination orders. In this paper we contend that identities, to enhance their control through switchings across networks and domains (netdoms, manage growing ambiguity via language’s reflexive and indexical features. We elaborate on several features—metapragmatics, heteroglossia, and poetics—and assert that they are seldom innocent performances to build consensus in the reproduction of social orders. On the contrary, language is inherently implicated in relations of domination. We then argue that metapragmatic control of stories acquired in countless netdom switchings leads to strong footings that secure resources and opportunity; that rhetorics that include rich heteroglossic voicing via structural holes generate stories that can be reflexively transposed to other institutional arenas; and that poetic control of speech styles may transform identities into power-law constellations with robust footing that decouple into prisms to preserve quality. Our goal is to twofold: First, to show that the reflexivity and indexicality of language emerges from myriad switchings across netdoms; and second, to demonstrate that reflexive and indexical language is critical to identities’ struggles for control—of footing and domination—via their switchings across rapidly polymerizing netdoms.
Muscle reflex in heart failure: the role of exercise training
Directory of Open Access Journals (Sweden)
HanjunWang
2012-10-01
Full Text Available Exercise evokes sympathetic activation and increases blood pressure and heart rate. Two neural mechanisms that cause the exercise-induced increase in sympathetic discharge are central command and the exercise pressor reflex (EPR. The former suggests that a volitional signal emanating from central motor areas leads to increased sympathetic activation during exercise. The latter is a reflex originating in skeletal muscle which contributes significantly to the regulation of the cardiovascular and respiratory systems during exercise. The afferent arm of this reflex is composed of metabolically sensitive (predominantly group IV, C-fibers and mechanically sensitive (predominately group III, A-delta fibers afferent fibers. Activation of these receptors and their associated afferent fibers reflexively adjusts sympathetic and parasympathetic nerve activity during exercise. In heart failure, the sympathetic activation during exercise is exaggerated, which potentially increases cardiovascular risk and contributes to exercise intolerance during physical activity in chronic heart failure (CHF patients. A therapeutic strategy for preventing or slowing the progression of the exaggerated EPR may be of benefit in CHF patients. Long-term exercise training (ExT, as a non-pharmacological treatment for CHF increases exercise capacity, reduces sympatho-excitation and improves cardiovascular function in CHF animals and patients. In this review, we will discuss the effects of ExT and the mechanisms that contribute to the exaggerated EPR in the CHF state.
Positioning Resumes and Cover Letters as Reflective-Reflexive Process
Randazzo, Chalice
2012-01-01
Although the resume and cover letter genre is widely discussed in both popular and scholarly publications, discussion thus far has failed to acknowledge that the process of creating a resume and cover letter has the potential for encouraging students' reflective and reflexive capacities. This article suggests that business communication educators…
A Maurey type result for operator spaces
Junge, Marius
2007-01-01
The little Grothendieck theorem for Banach spaces says that every bounded linear operator between $C(K)$ and $\\ell_2$ is 2-summing. However, it is shown in \\cite{J05} that the operator space analogue fails. Not every cb-map $v : \\K \\to OH$ is completely 2-summing. In this paper, we show an operator space analogue of Maurey's theorem : Every cb-map $v : \\K \\to OH$ is $(q,cb)$-summing for any $q>2$ and hence admits a factorization $\\|v(x)\\| \\leq c(q) \\|v\\|_{cb} \\|axb\\|_q$ with $a,b$ in the unit ball of the Schatten class $S_{2q}$.
Chen, Yi; Wang, Yu; Chen, Lu; Sun, Chenyuo; English, Arthur W.; Wolpaw, Jonathan R.; Chen, Xiang Yang
2010-01-01
Operant conditioning of the spinal stretch reflex or its electrical analog, the H-reflex, produces spinal cord plasticity and can thereby affect motoneuron responses to primary afferent input. To explore whether this conditioning can affect the functional outcome after peripheral nerve injury, we assessed the effect of up-conditioning soleus (SOL) H-reflex on SOL and tibialis anterior (TA) function after sciatic nerve transection and repair. Sprague-Dawley rats were implanted with EMG electro...
A new hypothesis of cause of syncope: trigeminocardiac reflex during extraction of teeth.
Arakeri, Gururaj; Arali, Veena
2010-02-01
Transient Loss Of Consciousness (TLOC) or vasovagal syncope is well known phenomenon in dental/maxillofacial surgery. Despite considerable study of vasovagal syncope, its pathophysiology remains to be fully elucidated. After having encountered a case of trigeminocardiac reflex after extraction of maxillary first molar we observed and studied 400 extractions under local anesthesia to know the relation between trigeminocardiac reflex and syncope. We make hypothesis that trigeminocardiac reflex which is usually seen under general anesthesia when all sympathetic reflexes are blunted can also occur under local anesthesia during extractions of maxillary molars (dento-cardiac reflex) and mediate syncope. PMID:19815349
Mu, Laiyong; Ritzmann, Roy E
2008-03-01
Tethered cockroaches turn from unilateral antennal contact using asymmetrical movements of mesothoracic (T2) legs (Mu and Ritzmann in J Comp Physiol A 191:1037-1054, 2005). During the turn, the leg on the inside of the turn (the inside T2 leg) has distinctly different motor patterns from those in straight walking. One possible neural mechanism for the transformation from walking to inside leg turning could be that the descending commands alter a few critical reflexes that start a cascade of physical changes in leg movement or posture, leading to further alterations. This hypothesis has two implications: first, the descending activities must be able to influence thoracic reflexes. Second, one should be able to initiate the turning motor pattern without descending signals by mimicking a point farther down in the reflex cascade. We addressed the first implication in this paper by experiments on chordotonal organ reflexes. The activity of depressor muscle (Ds) and slow extensor tibia muscle (SETi) was excited and inhibited by stretching and relaxing the femoral chordotonal organ. However, the Ds responses were altered after eliminating the descending activity, while the SETi responses remain similar. The inhibition to Ds activity by stretching the coxal chordotonal organ was also altered after eliminating the descending activity. PMID:18094976
Retention of primitive reflexes and delayed motor development in very low birth weight infants.
Marquis, P J; Ruiz, N A; Lundy, M S; Dillard, R G
1984-06-01
Primitive reflexes and motor development were evaluated in 127 very low birth weight (VLBW) infants (birth weight less than 1501 grams) at four months corrected age. The asymmetrical tonic neck reflex, tonic labyrinth reflex, and Moro reflex were assessed for each child. The ability of each child to reach (obtain a red ring) and roll were observed. The child's performance on the gross motor scale of the Denver Development Screening Test was recorded. Thirty-seven term infants were administered identical evaluations at four months of age. The VLBW infants retained stronger primitive reflexes and exhibited a significantly higher incidence of motor delays than term infants. Significant correlations existed between the strength of the primitive reflexes and early motor development for VLBW infants. This study confirms a high incidence of motor delays among VLBW infants and demonstrates a clear association between retained primitive reflexes and delayed motor development in VLBW infants. PMID:6736257
Locally Convex Valued Rectangular Metric Spaces and The Kannan's Fixed Point Theorem
Abdeljawad, Thabet; Tu?rkog?lu, Duran
2011-01-01
Rectangular TVS-cone metric spaces are introduced and Kannan's fixed point theorem is proved in these spaces. Two approaches are followed for the proof. At first we prove the theorem by a direct method using the structure of the space itself. Secondly, we use the nonlinear scalarization used recently by Wei-Shih Du in [A note on cone metric fixed point theory and its equivalence, {Nonlinear Analysis},72(5),2259-2261 (2010).] to prove the equivalence of the Banach contraction...
Post-activation depression of Soleus stretch reflexes in healthy and spastic humans.
DEFF Research Database (Denmark)
Grey, Michael J; Klinge, Klaus
2007-01-01
Reduced depression of transmitter release from Ia afferents following previous activation (post-activation depression) has been suggested to be involved in the pathophysiology of spasticity. However, the effect of this mechanism on the myotatic reflex and its possible contribution to increased reflex excitability in spastic participants has not been tested. To investigate these effects, we examined post-activation depression in Soleus H-reflex responses and in mechanically evoked Soleus stretch reflex responses. Stretch reflex responses were evoked with consecutive dorsiflexion perturbations delivered at different intervals. The magnitude of the stretch reflex and ankle torque response was assessed as a function of the time between perturbations. Soleus stretch reflexes were evoked with constant velocity (175 degrees /s) and amplitude (6 degrees ) plantar flexion perturbations. Soleus H-reflexes were evoked by electrical stimulation of the tibial nerve in the popliteal fossa. The stretch reflex and H-reflex responses of 30 spastic participants (with multiple sclerosis or spinal cord injury) were compared with those of 15 healthy participants. In the healthy participants, the magnitude of the soleus stretch reflex and H-reflex decreased as the interval between the stimulus/perturbation was decreased. Similarly, the stretch-evoked torque decreased. In the spastic participants, the post-activation depression of both reflexes and the stretch-evoked torque was significantly smaller than in healthy participants. These findings demonstrate that post-activation depression is an important factor in the evaluation of stretch reflex excitability and muscle stiffness in spasticity, and they strengthen the hypothesis that reduced post-activation depression plays a role in the pathophysiology of spasticity.
Post-activation depression of soleus stretch reflexes in healthy and spastic humans
DEFF Research Database (Denmark)
Grey, Michael James; Klinge, Klaus
2007-01-01
Reduced depression of transmitter release from Ia afferents following previous activation (post-activation depression) has been suggested to be involved in the pathophysiology of spasticity. However, the effect of this mechanism on the myotatic reflex and its possible contribution to increased reflex excitability in spastic participants has not been tested. To investigate these effects, we examined post-activation depression in Soleus H-reflex responses and in mechanically evoked Soleus stretch reflex responses. Stretch reflex responses were evoked with consecutive dorsiflexion perturbations delivered at different intervals. The magnitude of the stretch reflex and ankle torque response was assessed as a function of the time between perturbations. Soleus stretch reflexes were evoked with constant velocity (175 degrees /s) and amplitude (6 degrees ) plantar flexion perturbations. Soleus H-reflexes were evoked by electrical stimulation of the tibial nerve in the popliteal fossa. The stretch reflex and H-reflex responses of 30 spastic participants (with multiple sclerosis or spinal cord injury) were compared with those of 15 healthy participants. In the healthy participants, the magnitude of the soleus stretch reflex and H-reflex decreased as the interval between the stimulus/perturbation was decreased. Similarly, the stretch-evoked torque decreased. In the spastic participants, the post-activation depression of both reflexes and the stretch-evoked torque was significantly smaller than in healthy participants. These findings demonstrate that post-activation depression is an important factor in the evaluation of stretch reflex excitability and muscle stiffness in spasticity, and they strengthen the hypothesis that reduced post-activation depression plays a role in the pathophysiology of spasticity. Udgivelsesdato: 2008-Feb
Rhythmic arm cycling differentially modulates stretch and H-reflex amplitudes in soleus muscle.
Palomino, Andres F; Hundza, Sandra R; Zehr, E Paul
2011-10-01
During rhythmic arm cycling, soleus H-reflex amplitudes are reduced by modulation of group Ia presynaptic inhibition. This suppression of reflex amplitude is graded to the frequency of arm cycling with a threshold of 0.8 Hz. Despite the data on modulation of the soleus H-reflex amplitude induced by rhythmic arm cycling, comparatively little is known about the modulation of stretch reflexes due to remote limb movement. Therefore, the present study was intended to explore the effect of arm cycling on stretch and H-reflex amplitudes in the soleus muscle. In so doing, additional information on the mechanism of action during rhythmic arm cycling would be revealed. Although both reflexes share the same afferent pathway, we hypothesized that stretch reflex amplitudes would be less suppressed by arm cycling because they are less inhibited by presynaptic inhibition. Failure to reject this hypothesis would add additional strength to the argument that Ia presynaptic inhibition is the mechanism modulating soleus H-reflex amplitude during rhythmic arm cycling. Participants were seated in a customized chair with feet strapped to footplates. Three motor tasks were performed: static control trials and arm cycling at 1 and 2 Hz. Soleus H-reflexes were evoked using single 1 ms pulses of electrical stimulation delivered to the tibial nerve at the popliteal fossa. A constant M-wave and ~6% MVC activation of soleus were maintained across conditions. Stretch reflexes were evoked using a single sinusoidal pulse at 100 Hz given by a vibratory shaker placed over the triceps surae tendon and controlled by a custom-written LabView program. Results demonstrated that rhythmic arm cycling that was effective for conditioning soleus H-reflexes did not show a suppressive effect on the amplitude of the soleus stretch reflex. We suggest this indicates that stretch reflexes are less sensitive to conditioning by rhythmic arm movement, as compared to H-reflexes, due to the relative insensitivity to Ia presynaptic inhibition. PMID:21901451
Almost automorphic functions with values in p-Frechet spaces
Directory of Open Access Journals (Sweden)
Gaston M. N'Guerekata
2008-02-01
Full Text Available In this paper we develop a theory of almost automorphic functions with values in p-Frechet spaces, $0
spaces and the Hardy space $H^{p}$. Although the p-norm for $0
Banach spaces are extended to this case. Applications to semigroups of linear operators and to dynamical systems in p-Frechet spaces are given.
Directory of Open Access Journals (Sweden)
Özdemir Ismet
2014-06-01
Full Text Available In this paper, we study the existence of the solutions of a class of functional integral equations which contain a lot of classical nonlinear integral equations as special cases. We consider the solvability of the equations in the Banach algebra of continuous functions on a closed and bounded interval. The main tools here are the measure of noncompactness and the suitable fixed point theorem for the product of two operators in the Banach algebra.
Generalized coorbit space theory and inhomogeneous function spaces of Besov-Lizorkin-Triebel type
Rauhut, Holger
2010-01-01
Coorbit space theory is an abstract approach to function spaces and their atomic decompositions. The original theory developed by Feichtinger and Gr{\\"o}chenig in the late 1980ies heavily uses integrable representations of locally compact groups. Their theory covers, in particular, homogeneous Besov-Lizorkin-Triebel spaces, modulation spaces, Bergman spaces, and the recent shearlet spaces. However, inhomogeneous Besov-Lizorkin-Triebel spaces cannot be covered by their group theoretical approach. Later it was recognized by Fornasier and the first named author that one may replace coherent states related to the group representation by more general abstract continuous frames. In the first part of the present paper we significantly extend this abstract generalized coorbit space theory to treat a wider variety of coorbit spaces. A unified approach towards atomic decompositions and Banach frames with new results for general coorbit spaces is presented. In the second part we apply the abstract setting to a specific ...
Two mechanisms for microwave generation: Reflexing electrons and oscillating virtual cathode
International Nuclear Information System (INIS)
The Air Force Weapons Laboratory has begun an experimental program to investigate the generation of high power microwaves with a relativistic electron beam source. The experiment and several modifications were simulated at Los Alamos using CCUBE, two-dimensional, fully electromagnetic, relativistic particle-in-cell simulation code. Two mechanisms appear to produce microwaves: (1) reflexing electrons trapped in a potential well between the cathode and a virtual cathode which formed because the emitted beam current exceeded the space-charge limit, and (2) the virtual cathode oscillating in position. Our goal is to understand the interplay between these two mechanisms and to study systems in which either one of the two is dominant. The machine characteristics are: 1.4 MV diode voltage, frequency tuning range 1-20 GHz, microwave power levels around 1 GW. A thin anode foil was placed at various distances from the cathode tip
Cavalli, Alessandra
2014-09-01
This paper attempts to describe how, in the very first months of extra-uterine life, personality structures are formed around notions of personal space, separateness, attachment and individuation. The contribution of a forgotten Hungarian analyst, Imre Hermann, who wrote about the 'clinging reflex', will be explored in relation to the origin of Bowlby's concept of attachment and Rey's theoretical understanding of personal space. Particular attention will be given to transitions, transitional experiences and the development of a sense of internal space. Vignettes from infant observations will be used to illustrate the theoretical frame of reference. Clinical material from the analysis of a child and an adult patient will be provided to postulate how a distorted perception of personal space and separateness in the first few months of life may affect the capacity to attach and to individuate. PMID:25155677
Fixed point theory in distance spaces
Kirk, William
2014-01-01
This is a monograph on fixed point theory, covering the purely metric aspects of the theory–particularly results that do not depend on any algebraic structure of the underlying space. Traditionally, a large body of metric fixed point theory has been couched in a functional analytic framework. This aspect of the theory has been written about extensively. There are four classical fixed point theorems against which metric extensions are usually checked. These are, respectively, the Banach contraction mapping principal, Nadler’s well known set-valued extension of that theorem, the extension of Banach’s theorem to nonexpansive mappings, and Caristi’s theorem. These comparisons form a significant component of this book. This book is divided into three parts. Part I contains some aspects of the purely metric theory, especially Caristi’s theorem and a few of its many extensions. There is also a discussion of nonexpansive mappings, viewed in the context of logical foundations. Part I also contains certain re...
Changes in soleus H-reflex during walking in middle-aged, healthy subjects
DEFF Research Database (Denmark)
Raffalt, Peter C; Alkjær, Tine
2015-01-01
INTRODUCTION: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4±6.9 years) and 15 young (mean age 23.7±3.9 years) subjects were compared. METHODS: The H-reflex amplitude, muscle activity (EMG) of the soleus and tibialis anterior muscles, and EMG/H-reflex gain were measured during 4-km/h treadmill walking. RESULTS: The normalized H-reflex amplitude was lower in the swing phase for the middle-aged group, and there was no difference in muscle activity. EMG/H-reflex gain did not differ between groups. CONCLUSIONS: H-reflex amplitude during walking was affected by aging, and changes during the swing phase could be seen in the middle-aged subjects. Subdividing the 2 age groups into groups of facilitated or suppressed swing-phase H-reflex revealed that the H-reflex amplitude modulation pattern in the group with facilitated swing-phase H-reflex may be influenced by aging.
Is the maturation of monosynaptic stretch reflex in rats affected by neonatal malnutrition?
Freitas-Silva, S R; Manhães-de-Castro, R; Pérot, C
2008-10-01
We compared the maturation of the monosynaptic stretch reflex in control rats and in rats submitted to neonatal malnutrition. Electrical stimulations of the sciatic nerve were applied in wakeful rats of different ages (21-90 days) to record, by surface electrodes, the maximal direct motor response (M(max)) or the maximal Hoffmann reflex (H(max)). Percussion on the Achilles tendon induced the T-reflex. Animals submitted to neonatal malnutrition showed significant reductions in H-reflex latency and in velocity index of nervous conduction. The H- or T-reflex amplitudes were lower for malnourished rats of 21 days but the difference was significant only for the T(max)/M(max) ratios. The reflexes evoked at older ages did not present differences between control and malnourished rats. In conclusion, rats submitted to neonatal malnutrition present long-term alteration in reflex latency and nervous conduction velocity. Neonatal malnutrition also alters the reflex excitability at weaning but, since the rat were submitted to a normal diet after weaning, a normal reflex excitability was rapidly recovered which indicates a remarkable plasticity of the reflex pathway. PMID:18782480
"A case of self-induced reflex epilepsy "
Directory of Open Access Journals (Sweden)
"Moatamedi M
2000-10-01
Full Text Available The term reflex epilepsy in reserved for a small subgroup o seizures that occur regularly in response to specific stimuli. Our patient is a 20- year old male, who had pleasure, euphoria, loss of conciousness and generalized tonic- clonic convulstion when he watched TV since ten years. During puberty the patient that self-induced reflex epilepsy with photic stimulation, when watching TV or looking at sun and with had moving in front of his eyes to produce flickers. The patient first had sex pleasure, euphoria, erection and ejaculation, and then developed loss of consiousness and generalized tonic- clonic seizure, that took about 4-5 min. what is more intersing is that he asked us for a kind of drug that controlled his generalized tonic-clonic seizures but not his pleasure and orgasm, and he said that he would refuse any drug interfered with his orgasm.
Lack of trigemino-cervical reflexes in progressive supranuclear palsy.
Bartolo, Michelangelo; Serrao, Mariano; Perrotta, Armando; Tassorelli, Cristina; Sandrini, Giorgio; Pierelli, Francesco
2008-07-30
Trigemino-cervical reflexes (TCRs) are multisynaptic neck muscle withdrawal responses that are clearly identifiable in humans. Mediated by neural circuits at brainstem level, these reflex responses have been found to be significantly impaired in patients with Parkinson's disease (PD), and it has been hypothesized that a degeneration of brainstem neural structures could play a role in these abnormalities. Because extensive neuronal degeneration at brainstem level has been demonstrated in progressive supranuclear palsy (PSP), in this pilot study we evaluated the TCR responses in 12 subjects with PSP, and in 16 healthy controls. The TCRs were absent in 11 out of the 12 PSP patients while clear responses were evoked in all the healthy subjects. These findings indicate that PSP patients are unable to react to the painful stimuli to the face, suggesting a generalized impairment of the brainstem circuits mediating TCRs. PMID:18561341
[Typological characteristics of conditioned reflex learning in monkeys].
Sheremet, I P; Belkaniia, G S
1987-01-01
Three types of conditioned learning dynamics were singled out in males of the rhesus monkeys by the speed of formation of a positive motor instrumental reflex and differentiation. Type I is characterized by the fastest mastering of separate subprograms and of the whole test program of conditioned behaviour, by optimal functional characteristics in the process of learning and by a high adaptivity in new conditions. The most prolonged formation of the conditioned reflexes occurs in monkeys of the III-d type; 50% of them do not master the whole learning program; monkeys with such type of learning dynamics have no adaptation of previously acquired conditioned stereotype to new environmental conditions. Monkeys of the II-nd type of learning dynamics possess intermediate characteristics. A notion is substantiated of interconnection of higher nervous activity properties with typological characteristics of conditioned learning dynamics in monkeys. PMID:3433932
[A case of trigeminocardiac reflex in the pterional approach].
Kitabayashi, Mayumi; Nakamura, Kazuhito; Murata, Takaho
2012-10-01
Trigeminocardiac reflex (TCR) is a type of vasovagal reflex which happens in stimulation of the trigeminal nerve. We present a case of TCR in the pterional approach for clipping of an unruptured anterior communicating artery (Acom) aneurysm. A 69-year-old female was evaluated because of syncope. MRI showed incidentally Acom aneurysm. During the operation for clipping this aneurysm, only when we manipulated the dura attached to the sphenoid ridge, a total of three times, asystole appeared temporarily. In this case, a branch of the trigeminal nerve accompanying the middle meningeal artery was stimulated, then TCR may have been induced, leading to asystole. Furthermore, it seems that remifentanil used for anesthesia is related to TCR. PMID:23045405
Avoidance and management of trigeminocardiac reflex complicating awake-craniotomy.
Prabhu, Vikram C; Bamber, Norman I; Shea, John F; Jellish, W Scott
2008-12-01
The trigeminocardiac reflex occurs from manipulation or stimulation of peripheral branches or the central component of the trigeminal nerve and consists of bradycardia, hypotension, apnea, and increased gastric motility. The efferent limb of the response is mediated by the vagus nerve. This 65-year-old Caucasian male suffered an episode of bradycardia progressing to transient asystole during the course of an awake-craniotomy procedure for tumor resection. The cardiac rhythm changes resolved with administration of intravenous atropine, removal of the precipitating stimulus, and application of topical anesthetic on the dura of the middle cranial fossa. The trigeminocardiac response may complicate the course of a craniotomy and may place an awake, unintubated patient at increased risk for morbidity. The reflex may be prevented by anesthetizing the dura innervated by the trigeminal nerve via injection or topical application of local anesthetic. If encountered, removal of the stimulus, airway protection, and administration of vagolytic medications are measures that need to be considered. PMID:18845385
Trigeminocardiac reflex: the current clinical and physiological knowledge.
Chowdhury, Tumul; Mendelowith, David; Golanov, Eugene; Spiriev, Toma; Arasho, Belachew; Sandu, Nora; Sadr-Eshkevari, Pooyan; Meuwly, Cyrill; Schaller, Bernhard
2015-04-01
The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported in all the surgical procedures in which a structure innervated by the trigeminal nerve is involved. Although, there is an abundant literature with reports of incidences and risk factors of the TCR; the physiological significance and function of this brainstem reflex has not yet been fully elucidated. In addition, there are complexities within the TCR that requires examination and clarification. There is also a growing need to discuss its cellular mechanism and functional consequences. Therefore, the current review provides an updated examination of the TCR with a particular focus on the mechanisms and diverse nature of the TCR. PMID:25602626
Abnormal oculocardiac reflex in two patients with Marcus Gunn syndrome.
Pandey, Maitree; Baduni, Neha; Jain, Aruna; Sanwal, Manoj Kumar; Vajifdar, Homay
2011-07-01
Marcus Gunn phenomenon is seen in 4 to 6% of congenital ptosis patients. We report two cases of abnormal oculocardiac reflex during ptosis correction surgery. Marcus Gunn syndrome is an autosomal dominant condition with incomplete penetrance. It is believed to be a neural misdirection syndrome in which fibres of the motor division of the trigeminal nerve are congenitally misdirected into the superior pterygoid and the levator muscles. Anesthetic considerations include taking a detailed history about any previous anaesthetic exposure and any reaction to it as this syndrome has a high probability of being associated with malignant hyperthermia. It is also postulated that an atypical oculocardiac reflex might be initiated in these patients as seen in our patients, so precautions must be taken for its prevention and early detection. PMID:21897519
Modeling multistage decision processes with Reflexive Game Theory
Tarasenko, Sergey
2012-01-01
This paper introduces application of Reflexive Game Theory to the matter of multistage decision making processes. The idea behind is that each decision making session has certain parameters like "when the session is taking place", "who are the group members to make decision", "how group members influence on each other", etc. This study illustrates the consecutive or sequential decision making process, which consist of two stages. During the stage 1 decisions about the parame...
About the turbulent scale dependent response of reflexed airfoils
Scientific Electronic Library Online (English)
J. S., Delnero; J., Colman; U., Boldes; M., Martinez; J., Marañón di Leo; F. A., Bacchi.
2005-10-01
Full Text Available Boundary layer wind tunnel experiments have been conducted to explore differences in the aerodynamic behavior of two autostable or reflexed airfoils, with different positive camber submitted to three different incoming flows with the same mean velocity but with different turbulence characteristics. [...] The variations of lift and drag coefficients due to the path of turbulent structures with different scales are presented. The experiments were performed at a mean speed of 10 m/sec, corresponding to a Reynolds Number of 205000.
Stimulation of the corneal blinking reflex by ionizing radiation
Energy Technology Data Exchange (ETDEWEB)
Tobias, C.; Luce, J.; Yanni, N.; Brustad, T.; Lyman, J.; Kimura, S.
1961-05-04
Accelerated alpha particles from the Berkeley heavy-ion linear accelerator were used in a series of experiments designed to elucidate the conditions by which radiation can stimulate or modify nerve action in mammals. Single millisecond pulses in excess of 40,000 radsor pulse trains of less than 1 sec duration elicited the corneal blinking reflex when delivered to the cornea of unanesthetized rabbits. The lowest threshold dose was observed when the Bragg ionization peak was placed at 140 {mu} depth.
An evolutionary perspective on reflective and reflexive processing
Directory of Open Access Journals (Sweden)
AronKBarbey
2012-07-01
Full Text Available Human neuroscience has seen a recent boom in studies on reflective, controlled, explicit social cognitive functions like imitation, perspective?taking, and empathy. The relationship of these higher?level functions to lower?level, reflexive, automatic, implicit functions is an area of current research. As the field continues to address this relationship, we suggest that an evolutionary, comparative approach will be useful, even essential. There is a large body of research on reflexive, automatic, implicit processes in animals. A growing perspective sees social cognitive processes as phylogenically continuous, making findings in other species relevant for understanding our own. One of these phylogenically continuous processes appears to be self?other matching or simulation. Mice are more sensitive to pain after watching other mice experience pain; geese experience heart rate increases when seeing their mate in conflict; and infant macaques, chimpanzees, and humans automatically mimic adult facial expressions. In this article, we review findings in different species that illustrate how such reflexive processes are related to (“higher order” reflexive processes, such as cognitive empathy, theory of mind, and learning by imitation. We do so in the context of self?other matching in three different domains – in the motor domain (somatomotor movements, in the perceptual domain (eye movements and cognition about visual perception, and in the autonomic/emotional domain. We also review research on the developmental origin of these processes and their neural bases across species. We highlight gaps in existing knowledge and point out some questions for future research. We conclude that our understanding of the psychological and neural mechanisms of self?other mapping and other functions in our own species can be informed by considering the layered complexity these functions in other species.
Impulsive consumption and reflexive thought: Nudging ethical consumer behavior
Lades, Leonhard K.
2012-01-01
The paper deals with impulsive consumption and highlights the roles that cognitive and motivational aspects of reflexive thought (namely self-control and self-image motives, respectively) play in intertemporal decisions. While self-control inhibits individuals from consuming impulsively, self-image motives can induce impulsive consumption. Based on recent neuroscientific findings about 'wanting'-'liking' dissociations, the paper presents a potential motivational mechanism underlying such impu...
Trigeminocardiac reflex: a MaxFax literature review.
Bohluli, Behnam; Ashtiani, Abbas Kazemi; Khayampoor, Anahita; Sadr-Eshkevari, Pooyan
2009-08-01
Trigeminocardiac reflex (TCR) is a shocking event in the course of operation involving the maxillofacial area. The authors have tried to present an overview on the history, clinical implications, literature review, anatomic and biologic basis, predisposing and triggering factors, and management of the event. Being familiar with the presentations, preventive measures, and management procedures are seemingly the most important aspects of the TCR to oral and maxillofacial surgeons and anesthesiologists. PMID:19615657
The cough reflex in animals: Relevance to human cough research
Canning, Brendan J.
2007-01-01
All mammalian species studied cough or display some similar respiratory reflex upon aerosol challenge with tussigenic stimuli such as citric acid or capsaicin. Animals cough to the same stimuli that evoke coughing in humans, and therapeutic agents that display antitussive effects in human studies also prevent coughing in animals. The many invasive procedures and complementary in vitro studies possible in animals but readily reproduced in human subjects, along with the proven predictive value ...
Abnormal oculocardiac reflex in two patients with Marcus Gunn syndrome
Pandey, Maitree; Baduni, Neha; Jain, Aruna; Sanwal, Manoj Kumar; Vajifdar, Homay
2011-01-01
Marcus Gunn phenomenon is seen in 4 to 6% of congenital ptosis patients. We report two cases of abnormal oculocardiac reflex during ptosis correction surgery. Marcus Gunn syndrome is an autosomal dominant condition with incomplete penetrance. It is believed to be a neural misdirection syndrome in which fibres of the motor division of the trigeminal nerve are congenitally misdirected into the superior pterygoid and the levator muscles. Anesthetic considerations include taking a detailed histor...
Cough reflex sensitivity in adolescents with diabetic autonomic neuropathy
Ciljakova M; Vojtkova J; Durdik P; Turcan T; Petrikova M; Michnova Z; Banovcin P
2009-01-01
Abstract Objective Diabetic autonomic neuropathy (DAN) is one of the chronic complications of diabetes mellitus which can involve one or more organ systems. DAN without apparent symptoms is more often in childhood and adolescence. While heart rate variability (HRV) and Ewing's battery of cardiovascular tests are regarded as a gold standard for the diagnosis of DAN, the examination of cough reflex sensitivity (CRS) is another possibility. The aim of this study was to compare HRV and CRS in chi...
Composition operators on function spaces
Singh, RK
1993-01-01
This volume of the Mathematics Studies presents work done on composition operators during the last 25 years. Composition operators form a simple but interesting class of operators having interactions with different branches of mathematics and mathematical physics. After an introduction, the book deals with these operators on Lp-spaces. This study is useful in measurable dynamics, ergodic theory, classical mechanics and Markov process. The composition operators on functional Banach spaces (including Hardy spaces) are studied in chapter III. This chapter makes contact with the theory of analytic functions of complex variables. Chapter IV presents a study of these operators on locally convex spaces of continuous functions making contact with topological dynamics. In the last chapter of the book some applications of composition operators in isometries, ergodic theory and dynamical systems are presented. An interesting interplay of algebra, topology, and analysis is displayed. This comprehensive and up-to-date stu...
The ecologic reflexivity in the context of hospital work
Directory of Open Access Journals (Sweden)
Silviamar Camponogara
2007-12-01
Full Text Available This article is about a thesis project, which aims to debate the relation between the hospital worker and the present ecologic problematic. The structuring of the object of study comes with the understanding that we live in a “reflexive” society (Giddens, 1997 and that, as social “actors” or characters we present manifestations related to this reflexivity. Also related to this, the ecologic problematic demands from all human beings a responsible behavior concerning the environment (Jonas, 1995. It brings as an aim: to analyze the manifestations of the ecologic reflexivity in the relation of the subjects with their work in a hospital. The research has a qualitative approach, through the strategy of case study, developed in a school-hospital, having as subjects the workers of that institution. The data were collected through a documental analysis and observation as well as a semi-structured interview. The analysis of the data (in progress will happen with the formation of an analysis corpus and also categorization, with later interpretation in the light of the theoretical referential.
The ecologic reflexivity in the context of hospital work
Directory of Open Access Journals (Sweden)
Silviamar Camponogara
2007-09-01
Full Text Available This article is about a thesis project, which aims to debate the relation between the hospital worker and the present ecologic problematic. The structuring of the object of study comes with the understanding that we live in a “reflexive” society (Giddens, 1997 and that, as social “actors” or characters we present manifestations related to this reflexivity. Also related to this, the ecologic problematic demands from all human beings a responsible behavior concerning the environment (Jonas, 1995. It brings as an aim: to analyze the manifestations of the ecologic reflexivity in the relation of the subjects with their work in a hospital. The research has a qualitative approach, through the strategy of case study, developed in a school-hospital, having as subjects the workers of that institution. The data were collected through a documental analysis and observation as well as a semi-structured interview. The analysis of the data (in progress will happen with the formation of an analysis corpus and also categorization, with later interpretation in the light of the theoretical referential.
Rapid motor learning in the translational vestibulo-ocular reflex
Zhou, Wu; Weldon, Patrick; Tang, Bingfeng; King, W. M.; Shelhamer, M. J. (Principal Investigator)
2003-01-01
Motor learning was induced in the translational vestibulo-ocular reflex (TVOR) when monkeys were repeatedly subjected to a brief (0.5 sec) head translation while they tried to maintain binocular fixation on a visual target for juice rewards. If the target was world-fixed, the initial eye speed of the TVOR gradually increased; if the target was head-fixed, the initial eye speed of the TVOR gradually decreased. The rate of learning acquisition was very rapid, with a time constant of approximately 100 trials, which was equivalent to or=1 d without any reinforcement, indicating induction of long-term synaptic plasticity. Although the learning generalized to targets with different viewing distances and to head translations with different accelerations, it was highly specific for the particular combination of head motion and evoked eye movement associated with the training. For example, it was specific to the modality of the stimulus (translation vs rotation) and the direction of the evoked eye movement in the training. Furthermore, when one eye was aligned with the heading direction so that it remained motionless during training, learning was not expressed in this eye, but only in the other nonaligned eye. These specificities show that the learning sites are neither in the sensory nor the motor limb of the reflex but in the sensory-motor transformation stage of the reflex. The dependence of the learning on both head motion and evoked eye movement suggests that Hebbian learning may be one of the underlying cellular mechanisms.
Reciprocal inhibition versus unloading response during stretch reflex in humans.
Manning, C D; McDonald, P L L; Murnaghan, C D; Bawa, P
2013-04-01
Rotation of an upper limb joint produces excitatory stretch reflex peaks M1 and M2 in the stretched muscles and simultaneous decrease in electromyographic (EMG) activity in the shortened muscles. The objective of this study was to examine whether the decreased activity in the antagonists (rINHIB) is purely from unloading of the spindles or receives active inhibition involving inhibitory interneurons. If rINHIB is due only to unloading, then the termination of rINHIB should vary with the duration of perturbation used to elicit stretch reflex, namely shorter stretches should result in shorter values of decreased periods of EMG. To examine this question, rectangular pulses, ranging in duration from 25 to 150 ms, were used to stretch wrist flexors or extensors with a torque motor. These rectangular pulses resulted in joint rotations which peaked at times (T(peak)) ranging from approximately 75-160 ms. As shown by previous authors, when the duration of rotation was shortened, the magnitude of M1 did not change, while the magnitude of M2 decreased. However, termination time of rINHIB in the shortened muscles did not change with change in T(peak), implying thereby that unloading of spindles of the antagonist muscles is not the only mechanism for the reduction in activity and that inhibitory reflex pathways most likely contribute. Possible sources of inhibition are discussed for the short- and long-latency inhibition. PMID:23354665
A Case of Trigeminocardiac Reflex During Infrastructure Maxillectomy.
Mohan, Suresh; Flis, Daniel W; O'Leary, Miriam A
2014-05-01
IMPORTANCE The trigeminocardiac reflex refers to the sudden development of bradycardia or even asystole with arterial hypotension from manipulation of any sensory branches of the trigeminal nerve. Although it has only rarely been associated with morbidity and tends to be self-limited with removal of the stimulus, it is an important phenomenon for head and neck surgeons to recognize and respond to. OBSERVATIONS We present the case of a woman in her late 60s with maxillary alveolar ridge squamous cell carcinoma who developed episodes of asystole and bradycardia during posterior maxillary manipulation for an infrastructure maxillectomy at a tertiary academic medical center. Administration of atropine and removal of the inciting stimulus sufficed to extinguish the episodes and allow procedure completion. CONCLUSIONS AND RELEVANCE The trigeminocardiac reflex can be provoked by a number of head and neck and skull base procedures including parotidectomy and posterior maxillectomy. Surgeons and anesthesiologists should be wary of inciting the reflex during manipulation of trigeminal branches. Careful dissection for prevention and early intervention with stimulus removal and anticholinergic use as needed are paramount to ensure good outcomes. PMID:24788865
Radiographic assessment of laryngeal reflexes in ketamine-anesthetized cats
International Nuclear Information System (INIS)
The competence of the laryngeal closure reflexes of cats anesthetized with ketamine was assessed. Radiographic evaluations of the respiratory and digestive tracts were made after colloidal barium suspension was instilled into the pharynges of conscious and ketamine-anesthetized cats. There was a significant ketamine dose-related response of spread of contrast medium into the supraglottic laryngeal area and into the stomach 2 minutes after contrast medium was instilled into the pharynx (P less than 0.05). Cats did not aspirate contrast medium into the lower respiratory tract. Three ketamine-anesthetized cats aspirated contrast medium into the subglottic area of the larynx, and 2 of these cats also aspirated the material into the cranial part of the trachea. This material was coughed up and swallowed within 5 minutes. Transit time of contrast medium into the stomach seemed to be increased in 11 of the 15 cats given the larger dosages of ketamine (24, 36, 48 mg/kg of body weight), compared with that in conscious cats and those given ketamine at 12 mg/kg. Competent laryngeal protective reflexes in cats can be maintained with ketamine anesthesia. Contrast radiography could be used as a diagnostic aid in ketamine-anesthetized cats suspected of laryngeal reflex abnormalities
Primitive reflexes in amyotrophic lateral sclerosis: prevalence and correlates.
Tremolizzo, Lucio; Susani, Emanuela; Lunetta, Christian; Corbo, Massimo; Ferrarese, Carlo; Appollonio, Ildebrando
2014-06-01
Identifying frontal impairment in ALS is an important goal albeit disease-dedicated tools are still scarce. For this reason, we decided to consider primitive reflexes (PRs), variably regarded as correlates of frontal release and/or of upper motor neuron (UMN) impairment, often in the setting of dementias. Specifically, the aims of this work consisted in assessing the exact prevalence of the combination of seven PRs in ALS, trying to clarify their role as putative proxies of cognitive impairment or of UMN dysfunction. In this cross-sectional study, 50 consecutive ALS outpatients were evaluated for the presence of: palmomental (PM), corneomandibular (CM), glabella tap (MY), rooting, sucking, snout, and grasping reflexes. Cognitive screening was performed by the Frontal Assessment Battery (FAB) and the Weigl's Sorting test (WST); UMN dysfunction was concomitantly evaluated. PM, CM and MY were more frequently detected (62, 52, and 44 % of the ALS sample, respectively), while the other reflexes were under-represented. Patients displaying three or more PRs had significantly lower FAB and WST scores. On the other hand, UMN dysfunction was only moderately associated to PRs. In conclusion, PRs' assessment is a promising complementary tool for screening cognitive impairment in ALS; however, further work will be necessary to establish its added value with respect to already existing ALS-dedicated screening tools for cognition. PMID:24728376
Hypercyclic operators on topological vector spaces
Shkarin, Stanislav
2010-01-01
Bonet, Frerick, Peris and Wengenroth constructed a hypercyclic operator on the locally convex direct sum of countably many copies of the Banach space $\\ell_1$. We extend this result. In particular, we show that there is a hypercyclic operator on the locally convex direct sum of a sequence $\\{X_n\\}_{n\\in\\N}$ of Fr\\'echet spaces if and only if each $X_n$ is separable and there are infinitely many $n\\in\\N$ for which $X_n$ is infinite dimensional. Moreover, we characterize induc...
Note on Kadets Klee property and Asplund spaces.
Czech Academy of Sciences Publication Activity Database
Hájek, Petr Pavel; Talponen, J.
2014-01-01
Ro?. 142, ?. 11 (2014), s. 3933-3939. ISSN 0002-9939 R&D Projects: GA ?R(CZ) GAP201/11/0345 Institutional support: RVO:67985840 Keywords : uniformly rotund norms * Banach spaces * sequences Subject RIV: BA - General Mathematics Impact factor: 0.627, year: 2013 http://www.ams.org/journals/proc/2014-142-11/S0002-9939-2014-12123-X/
Isomorphic classification of atomic weak L^p spaces
Leung, D H
1994-01-01
Let $\\msp$ be a measure space and let $1 0}t^{\\frac{1}{p}}f^*(t) < \\infty,\\] where $f^*$ is the decreasing rearrangement of $|f|$. It is a Banach space under a norm which is equivalent to the expression above. In this paper, we pursue the problem of classifying weak $L^p$ spaces isomorphically when $\\msp$ is purely atomic. It is also shown that if $\\msp$ is a countably generated $\\sigma$-finite measure space, then $\\wlp$ (if infinite dimensional) must be isomorphic to either $\\ell^\\infty$ or $\\seq$. The results of this article were presented at the conference in Columbia, Missouri in May, 1994.
Fock-Sobolev spaces and their Carleson measures
Cho, Hongrae; Zhu, Kehe
2012-01-01
We consider the Fock-Sobolev space $F^{p,m}$ consisting of entire functions $f$ such that $f^{(m)}$, the $m$-th order derivative of $f$, is in the Fock space $F^p$. We show that an entire function $f$ is in $F^{p,m}$ if and only if the function $z^mf(z)$ is in $F^p$. We also characterize the Carleson measures for the spaces $F^{p,m}$, establish the boundedness of the weighted Fock projection on appropriate $L^p$ spaces, identify the Banach dual of $F^{p,m}$, and compute the ...
A Reflex Charger with ZVS and Non-Dissipative Cells for Photovoltaic Energy Conversion
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Cheng-Tao Tsai
2015-02-01
Full Text Available In this paper, a reflex charger with zero-voltage-switching (ZVS and non-dissipative cells for photovoltaic (PV energy conversion is presented. The proposed reflex charger has the following advantages: (1 A ZVS cell is incorporated to reduce the switching losses of the main and auxiliary switches. Therefore, the conversion efficiency of the proposed reflex charger can be improved significantly; (2 A non-dissipative charging/discharging reflex cell is used to increase charging efficiency and extend lifecycle of battery. Finally, a prototype reflex charger with ZVS and non-dissipative cells is built and implemented. Experimental results are presented to verify the performance and the feasibility of the proposed reflex charger for PV energy conversion.
A comparative study on the presence of the asymmetrical tonic neck reflex in adult hemiplegia.
Warren, M L
1984-06-01
In this study, the intensity of the asymmetrical tonic neck reflex (ATNR) was measured in post-cerebrovascular accident (CVA) adults with hemiplegia and in neurologically intact adults to determine if the reflex exaggerated following CVA. Fourteen subjects with right and left hemiplegia were matched to neurologically intact subjects by age and sex and tested for the ATNR. Intensity of the reflex was measured using electromyography (EMG) biofeedback. The results indicate that no difference exists between the two groups in intensity of the reflex. The method of rotation used to elicit the reflex did significantly affect the strength of the muscle response. A possible explanation for observation of the reflex in the hemiplegic individual's movement and its significance in neuromuscular re-education programs is discussed. PMID:6742088
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Spiriev Toma
2012-10-01
Full Text Available Abstract Introduction Trigeminocardiac reflex is a well-known phenomenon in neurosurgery, craniofacial surgery, ophthalmology and interventional neuroradiology. Even though the trigeminocardiac reflex has become an important factor in skull base surgery and neurosurgery, the central form of trigeminocardiac reflex has only been described in adult subpopulations until now. Case presentation We present a clear form of repetitive trigeminocardiac reflex expressed during revision surgery of a giant (110×61mm right temporoparietal meningioma in an 18-month-old male Caucasian patient. After cessation of the surgical stimulus, his heart rate and mean arterial blood pressure returned to normal physiological levels. The further follow-up was uneventful. Conclusion Our case demonstrates that the central trigeminocardiac reflex also exists in pediatric patients, especially if manipulating trigeminal innervated structures or around the nerve itself. Whether the incidence and the behavior of the trigeminocardiac reflex is similar in pediatric neurosurgery compared with adult patients has to be shown in further studies.
Academic achievement and the paired Hoffman reflex in students practicing meditation.
Wallace, R K; Orme-Johnson, D W; Mills, P J; Dillbeck, M C
1984-11-01
The paired H reflex, considered to be the electrically evoked counterpart of the monosynaptic stretch reflex, provides a measure of motoneuron excitability under a variety of experimental and clinical conditions. It also offers a potentially useful tool in examining the neurophysiologic basis of alterations in reflex response in different states of awareness. This study investigated the relationship between the paired H reflex and academic achievement in students practicing the Transcendental Meditation program. The paired H reflex correlated significantly with grade point average, but not with SAT scores or any of three IQ measurements. These results suggest that the facilitation period of the paired H-reflex recovery curve may be a useful indicator of academic achievement, perhaps as a result of its relationship to awareness or wakefulness level. PMID:6392128
Variable Lebesgue spaces and hyperbolic systems
2014-01-01
This book targets graduate students and researchers who want to learn about Lebesgue spaces and solutions to hyperbolic equations. It is divided into two parts. Part 1 provides an introduction to the theory of variable Lebesgue spaces: Banach function spaces like the classical Lebesgue spaces but with the constant exponent replaced by an exponent function. These spaces arise naturally from the study of partial differential equations and variational integrals with non-standard growth conditions. They have applications to electrorheological fluids in physics and to image reconstruction. After an introduction that sketches history and motivation, the authors develop the function space properties of variable Lebesgue spaces; proofs are modeled on the classical theory. Subsequently, the Hardy-Littlewood maximal operator is discussed. In the last chapter, other operators from harmonic analysis are considered, such as convolution operators and singular integrals. The text is mostly self-contained, with only some mor...
Vestibulosympathetic reflex during the early follicular and midluteal phases of the menstrual cycle
Lawrence, Johnathan E.; Ray, Chester A.; Carter, Jason R.
2008-01-01
Evidence suggests that both the arterial baroreflex and vestibulosympathetic reflex contribute to blood pressure regulation, and both autonomic reflexes integrate centrally in the medulla cardiovascular center. A previous report indicated increased sympathetic baroreflex sensitivity during the midluteal (ML) phase of the menstrual cycle compared with the early follicular (EF) phase. On the basis of this finding, we hypothesize an augmented vestibulosympathetic reflex during the ML phase of th...
The oculocardiac reflex in an adult with a non-displaced orbital floor fracture.
Kasi, Sundeep K; Gorovoy, Ian R; Vagefi, M Reza; Kersten, Robert C
2014-08-01
The current dogma is that the oculocardiac reflex from orbital trapdoor fractures occurs only in children and young adults. We present the occurrence of the oculocardiac reflex in an adult with a non-displaced orbital floor fracture. CT demonstrated the adventitia surrounding the inferior rectus trapped in and below the orbital floor fracture. The patient's oculocardiac reflex resolved by early next morning, presumably from the tissue escaping from the orbital floor defect. PMID:24830832
Cornelissen, Laura; Fabrizi, Lorenzo; Patten, Deborah; Worley, Alan; Meek, Judith; Boyd, Stewart; Slater, Rebeccah; Fitzgerald, Maria
2013-01-01
Cutaneous flexion reflexes are amongst the first behavioural responses to develop and are essential for the protection and survival of the newborn organism. Despite this, there has been no detailed, quantitative study of their maturation in human neonates. Here we use surface electromyographic (EMG) recording of biceps femoris activity in preterm (response to tactile, punctate and clinically required skin-breaking lance stimulation of the heel. We show that all infants display a robust and long duration flexion reflex (>4 seconds) to a single noxious skin lance which decreases significantly with gestational age. This reflex is not restricted to the stimulated limb: heel lance evokes equal ipsilateral and contralateral reflexes in preterm and term infants. We further show that infant flexion withdrawal reflexes are not always nociceptive specific: in 29% of preterm infants, tactile stimulation evokes EMG activity that is indistinguishable from noxious stimulation. In 40% of term infants, tactile responses are also present but significantly smaller than nociceptive reflexes. Infant flexion reflexes are also evoked by application of calibrated punctate von Frey hairs (vFh), 0.8-17.2 g, to the heel. Von Frey hair thresholds increase significantly with gestational age and the magnitude of vFh evoked reflexes are significantly greater in preterm than term infants. Furthermore flexion reflexes in both groups are sensitized by repeated vFh stimulation. Thus human infant flexion reflexes differ in temporal, modality and spatial characteristics from those in adults. Reflex magnitude and tactile sensitivity decreases and nociceptive specificity and spatial organisation increases with gestational age. Strong, relatively non-specific, reflex sensitivity in early life may be important for driving postnatal activity dependent maturation of targeted spinal cord sensory circuits. PMID:24124564
Wang, Han-jun; Pan, Yan-xia; Wang, Wei-zhong; Gao, Lie; Zimmerman, Matthew C.; Zucker, Irving H.; Wang, Wei
2010-01-01
An exaggerated exercise pressor reflex (EPR) occurs in the chronic heart failure (CHF) state, which contributes to exercise intolerance and excessive sympathoexcitation during exercise. Exercise training (ExT) improves abnormal cardiovascular reflexes in CHF. Whether ExT can normalize the exaggerated EPR function remains to be determined. This study was designed to investigate the effects of ExT on the EPR and on the mechanical or metabolic components of this reflex in sham-operated and CHF r...
Arasho Belachew; Sandu Nora; Spiriev Toma; Kondoff Slavomir; Tzekov Christo; Schaller Bernhard
2010-01-01
Abstract Introduction The trigemino-cardiac reflex is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, trigemino-cardiac reflex has been reported to occur during neurosurgical skull-base surgery. Apart from the few clinical reports, the physiological function of this brainstem reflex has not yet been fully explored. Little is known regardin...
Is initial preservation of deep tendon reflexes in West Nile Virus paralysis a good prognostic sign?
Mojumder, Deb Kumar; Agosto, Melina; Wilms, Henrik; Kim, Jongyeol
2014-01-01
Typical West Nile virus paralysis is characterized by muscle weakness, decreased tone, and loss of deep tendon reflexes attributed to destruction of anterior horn cells. Two cases in which deep tendon reflexes were initially preserved in the presence of profound and persistent muscle weakness are presented here. In both cases, deep tendon reflexes were later severely attenuated or lost, while weakness of the involved muscles remained profound and unchanged. Both patients showed good motor rec...
Study of Achilles Tendon Reflex in Normal Korean and Various Thyroid Diseases
International Nuclear Information System (INIS)
In an attempt to establish the diagnostic value of Achilles tendon reflex and to determine the normal value of Achilles tendon reflex time in normal Korean, the author measured the Achilles tendon reflex time by photomotograph. This study was carried out in 272 cases with various thyroid diseases and 340 normal Korean. 1) The Achilles tendon reflex time in normal Korean was like this, between 11 years old and 20 years old; male (62 cases); 250±27 msec, female (36 cases); 266±27 msec, between 21 years old and 30 years old; male (38 cases); 271±27 msec, female (21 cases); 284±27 msec, between 31 years old and 40 years old; male (26 cases); 275±25 msec, female (29 cases); 291±27 msec, between 41 years old and 50 years old; male (20 cases); 286±35 msec, female (24 cases); 307±42 msec, between 51 years old and 60 years old, male (20 cases); 296±33 msec, female (20 cases); 318±46 msec, over 61 years; male (24 cases) 301±33 msec, female (20 cases); 325±35 msec. The Achilles tendon reflex time was delayed with increasing age and delayed in the female. 2) The Achilles tendon reflex time was markedly shortened to 221±20 msec in untreated hyperthyroidism. 3) The Achilles tendon reflex time was markedly delayed to 435±59 msec in hypothyroidism. 4) The Achilles tendon reflex time was not changed significantly in other thyroid diseases with norms thyroid function. 5) The Achilles tendon reflex time showed good correlationship with ETR, T3RU, 131Ib>3RU, 131I thyroid uptake and serum TSH. 6) Reproducibility of Achilles tendon reflex time was good, and no significant difference between left and right was noted. 7) Diagnostic accuracy of Achilles tendon reflex time was 71% in hyperthyroidism and 90% in hypothyroidism. 8) The Achilles tendon reflex time showed useful test to evaluate the clinical course of the hyperthyroidism.
Reduction of the linear reflex gain explained from the M1-M2 refractory period.
Klomp, Asbjorn; de Vlugt, Erwin; Meskers, Carel G M; de Groot, Jurriaan H; Arendzen, J Hans; van der Helm, Frans C T
2013-06-01
Linear system identification methods combined with neuromechanical modeling enable the quantification of reflex gains from recorded joint angular perturbation, torque, and/or electromyography (EMG). However, the stretch reflex response as recorded by EMG consists of multiple consecutive activation volleys (M1 and M2 responses) separated by a period of reduced activity and is nonlinearly related to joint perturbation. The goal of this study is to assess to what extent linear assumptions hold when quantifying these reflexive responses. Series of ramp-and-hold angular perturbations with fixed velocity but different ramp durations (and, therefore, different amplitudes) were applied to the wrist joint of seven healthy volunteers. Evoked EMG responses were compared to the reflex response estimated from a common linear reflex model relating EMG to perturbation velocity. Model fits described the measured EMG responses best when the perturbation and M1 response durations were equivalent. With increasing perturbation duration, i.e., amplitude, EMG response increased but reflex gain decreased due to the inert period after M1, which is believed to be related to alignment of the refractory period of the motoneurons. For angular joint perturbations exceeding the M1 duration (coinciding with 2 (°) of wrist joint rotation in this study), reflex gain variation may be largely explained from a shortcoming of the linear model in describing the nonlinear reflex response, and in particular the period of low reflexive activity after M1. PMID:23358942
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Postradiation dynamics of strengthened motor-defense conditioned reflex in rats-males irradiated with the doses of 94.111 and 137 Gy was studied. Phase disturbances of conditioned-reflex activity increased with enhancing irradiation dose have been revealed. Rapid recovery of conditioned reflex after short primary aggravation was a characteristic peculiarity. At that, the dynamics of relation of main nervous processes in cortex was noted for significant instability increasing with radiation syndrom development. Enhancement of force of electro-defense support promoted more effective strengthening of temporary connections and conditioned high stability of trained-reflex reactions during serious functional disturbances resulted from sublethal dose irradiation
Ertekin, Cumhur; Bademkiran, Fikret; Yalin, Sevket; Karapinar, Nevin; Uysal, Hilmi
2008-11-01
The withdrawal reflex in the short head of the biceps femoris muscle after electrical stimulation of the sural nerve at the ankle has been investigated in numerous studies. These studies have described two distinct responses: early (R-II) and late (R-III). However, withdrawal reflex activity of the adductor muscles in the legs has not been studied systematically. Adductor muscle reflex activity is important because it can produce serious clinical problems, such as adductor spasticity and spasms, during bladder surgery. The present study examined withdrawal reflex features of adductor muscles obtained by electrical and magnetic stimulation of the obturator nerve (ON) in 34 normal healthy subjects. Early adductor muscle withdrawal reflex responses were elicited by ipsilateral ON electrical stimulation with a mean latency of 45.7+/-2.0 ms (responses in 94% of subjects). Reflex responses were also obtained using magnetic stimulation at a similar incidence rate. Contralateral ON electrical stimulation resulted in a similar reflex, but with a lower incidence. ON and femoral nerve electrical and magnetic coil stimulation produced similar low-incidence responses in the vastus medialis. These findings indicate that short latency adductor withdrawal reflexes are easily obtained on both sides following electrical or magnetic stimulation of the ON, and they can be elicited by both nociceptive and nonnociceptive stimuli. These reflexes prepare the body for a proper response to incoming signals and likely serve to protect the pelvic floor and pelvic organs. PMID:18816621
Stretch reflex of quadriceps femoris and its relation to rigidity in Parkinson's disease.
Lopiano, Leonardo; Bergui, Mauro; Bergamasco, Bruno
1992-01-01
Much evidence suggests that parkinsonian rigidity is due to hyperactivity of a reflex arc. While tendon jerk and H reflex are not modified in Parkinson's disease (PD), the long-latency component of stretch reflex (LLR) shows an increased size in PD. It has been proposed that this modification could account for rigidity. We studied in 14 PD patients and 8 normal subjects the stretch reflex of the quadriceps femoris. The muscle was stretched by a torque motor in two experimental sets: at rest a...
A $\\phi$ - contraction Principle in Partial Metric Spaces with Self-distance Terms
Abdeljawad, Thabet; Zaidan, Younis; Shahzad, Naseer
2012-01-01
We prove a generalized contraction principle with control function in complete partial metric spaces. The contractive type condition used allows the appearance of self distance terms. The obtained result generalizes some previously obtained results such as the very recent " D. Ili\\'{c}, V. Pavlovi\\'{c} and V. Rako\\u{c}evi\\'{c}, Some new extensions of Banach's contraction principle to partial metric spaces, Appl. Math. Lett. 24 (2011), 1326--1330". An example is given to illu...
A simple proof to an extension of a theorem of A. Pazy in Hilbert space
International Nuclear Information System (INIS)
We prove that if (xn)n?0 is a non expansive sequence in a Hilbert space H, the sequence (nxn)n?1 converges strongly in H to the element of minimum norm in the closed convex hull of the sequence (xn+1-xn)n?0. This result was previously proved; the proof we give here is even much simpler and can be extended to a Banach space. 29 refs
Generalizations of the Lax-Milgram theorem
Drivaliaris, D
2008-01-01
We prove a linear and a nonlinear generalization of the Lax-Milgram theorem. In particular we give sufficient conditions for a real-valued function defined on the product of a reflexive Banach space and a normed space to represent all bounded linear functionals of the latter. We also give two applications to singular differential equations.
Generalizations of the Lax-Milgram Theorem
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Dimosthenis Drivaliaris
2007-05-01
Full Text Available We prove a linear and a nonlinear generalization of the Lax-Milgram theorem. In particular, we give sufficient conditions for a real-valued function defined on the product of a reflexive Banach space and a normed space to represent all bounded linear functionals of the latter. We also give two applications to singular differential equations.
Activity of motoneurons during fictitious scratch reflex in the cat.
Berkinblit, M B; Deliagina, T G; Orlovsky, G N; Feldman, A G
1980-07-14
(1) Intracellular recording of motoneurons of different hindlimb muscles: tibialis anterior (TA), gastrocnemius and soleus (GS), vastus crureus (Vast), posterior biceps and semitendinosus (PBSt), was carried out during the fictitious scratch reflex in decerebrate cats. (2) During the postural stage of the reflex, a depolarizaiton (3.8 mV on average) was observed in TA motoneurons accompanied by tonic discharge. No change of the membrane potential (MP) and no discharge were observed during this stage in GS, Vast and PBSt motoneurons. (3) In the rhythmical stage of the reflex, the MP of TA motoneurons changed only slightly during the 'long' (L) phase of the scratch cycle and remained at approximately the same level as during the postural stage. In this phase, motoneurons discharged at frequencies of 20-100 pps. In the 'short' (S) phase of the scratch cycle a strong repolarization occurred, the MP reached the same level as observed during resting conditons (MP0), and the discharge discontinued. (4) GS motoneurons were gradually depolarized during the second half of the L-phase. The depolarization reached its maximum (5.5 mV on average in relation to the MP0) on average in relation to the MP0) in the S-phase, and several action potentials were generated with intervals of 5-10 msec. Then, at the beginning of the L-phase, the motoneurons were repolarized and the MP reached the level of the MP0. The behavior of Vast motoneurons was essentially similar to that of GS motoneurons. (5) The PBSt motoneurons usually had two peaks of depolarization per cycle--in the S-phase and at the beginning of the L-phase. The maximal depolarization was 3.5 mV (on average). The motoneurons generated action potentials at one or both peaks of depolarization. (6) The possible organization of the central influences upon motoneurons of different muscles during scratching is discussed. PMID:7388601
Neural reflex of the canine pylorus to intraduodenal acid infusion.
Allescher, H D; Daniel, E E; Dent, J; Fox, J E; Kostolanska, F
1989-01-01
In 29 chloralose-urethane anesthetized dogs, a manometric assembly was inserted through a gastrostomy to monitor pressure of the pyloric region with a sleeve sensor. Antral and duodenal contractions were monitored with both manometric sideholes and serosal strain gauges. An additional tube channel allowed intraduodenal infusions 1-2 cm aborad from the pylorus. Intraluminal infusion of hydrochloric acid (0.1 N, 0.92 ml/min, for 2 min) reproducibly caused activation of motor activity in the pyloric region and peristaltic duodenal activity. Proximal duodenal activity probably contributed to the total phasic response recorded in the pylorus region. Excitatory responses could also be elicited by infusion of phenyl-biguanide (stimulant of sensory nerve endings), but not by control infusions with diluent (Krebs' buffer or saline). The motor response of the pyloric region to intraduodenal acid was blocked by intraduodenal application of 2% xylocaine. Atropine (30 micrograms/kg i.v. and 100 micrograms i.a.) or hexamethonium (10 mg/kg and 1 mg i.a.) markedly reduced or blocked the acid-induced pyloric motor response of this region but propranolol (1.0 mg/kg i.v. and 100 micrograms i.a.), phentolamine (1.5 mg/kg i.v. and 100 micrograms i.a.), or naloxone (200 micrograms/kg and 20 micrograms i.a.) had no effect. We believe these observations show the existence of a reflex from the duodenum to the pylorus in response to intraluminal stimuli mediated by a chain of cholinergic nerves. In the dog, endogenous opioid peptides do not contribute to the excitatory reflex pathway activated by intraduodenal acid or phenyl-biguanide. As intraluminal acid in the duodenum activates this reflex, it may play a role in the physiologic and pathophysiologic role of gastric emptying in this species. PMID:2562833
Predictive value of reflex-otalgia in locally radical radiotherapy of oropharynx carcinoma
International Nuclear Information System (INIS)
Background: Patients with carcinomas of the upper aero-digestive tract often suffer from ear pain as a tumor associated syndrome. This prospective study examines the predictive and prognostic value of this symptom. Patients and Methods: Ninety-six consecutive patients who completed a locally radical radiotherapy of a carcinoma of the oropharynx were prospectively evaluated and followed. Forty-nine out of 96 patients stated the symptom, either spontaneously or after questioning. The 2 groups showed no difference regarding TNM-classification, histology and total dose. Overall survival, local control and disease specific survival were calculated according to Kaplan-Meier and compared by the log-rank test. Results: A clinically complete remission was obtained in significantly fewer patients with reflex-otalgia as compared to patients without reflex-otalgia, 61.2% versus 89.3%, p<0.002. Local control of patients with reflex-otalgia was significantly less with 49%, mean follow-up 564 days, in comparison to local control in patients without reflex-otalgia, mean follow-up 613 days, p=0.01. Disease specific survival was significantly worse for patients with reflex-otalgia, p<0.012. The probability of local control of T1/T2 tumors with reflex-otalgia was similar to T3/T4 tumors without reflex-otalgia. Local control for all tumor categories combined is 74% for patients without reflex-otalgia versus 49% for patients with reflex-otalgia. Conclusion: In our patients, reflex-otalgiaonclusion: In our patients, reflex-otalgia is a new and statistically significant parameter for the probability of local control and disease specific survival. (orig.)
Study of multicomponent plasma parameters in the pulsed reflex discharge
Kovtun, Yu V.; Skibenko, A. I.; Skibenko, E. I.; Larin, Yu V.; Shapoval, A. N.; Volkov, E. D.; Yuferov, V. B.
2010-01-01
Parameters of a dense 10^13-10^14cm^-3) multicomponent gas-metal plasma in the pulsed reflex discharge with a moderate power (W \\leq 10 MW) have been studied. The dynamics of the plasma density in time, the mass-element composition of the plasma generated, the radial distribution of the electron density in plasma, the rotation velocity and the rotation frequency of a plasma layer with n_p \\geq n_crit, the radial electric field strength, and the recombination factor at the st...
Instrumentalization Theory and Reflexive Design in Animal Husbandry
Bos, A. P.
2008-01-01
In animal husbandry in The Netherlands, as in a wide variety of other societal areas, we see an increased awareness of the fact that progress cannot be attained anymore by simply repeating the way we modernized this sector in the decades before, due to the multiplicity of the problems to be dealt with. The theory of reflexive modernization articulates this macro-social phenomenon, and at the same time serves as a prescriptive master-narrative. In this paper, I analyse the relationship between...
Approximation of Müntz-Szász type in weighted spaces
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The paper looks at whether a system of exponentials exp(-?nt), Re?n>0, is complete in various function spaces on the half-line R+. Wide classes of Banach spaces E and F of functions on R+ are described such that this system is complete in E and F simultaneously. A test is established to determine when this system is complete in the weighted spaces C0 and Lp with weight (1+t)? on R+, for ?<0 and ?<-1, respectively. Bibliography: 18 titles
Okada, H; Honda, M; Ono, H
2001-05-01
Mice were used to record the spinal reflex potentials and to examine the effects of some drugs upon them. In anesthetized mice, laminectomy was performed in the lumbo-sacral region, and monosynaptic reflex potential (MSR) and polysynaptic reflex potential were recorded from the L5 ventral root after stimulation of the L5 dorsal root. Thyrotropin-releasing hormone (TRH) and 1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride (DOI) produced transient and long-lasting increases in the MSR amplitude, respectively. Tolperisone hydrochloride and baclofen produced transient and long-lasting MSR depressions, respectively. These results show that mice can be used to record spinal reflex potentials, and that it may be possible to study the spinal cord function of mutant and knockout mice using this method. PMID:11430467
Glass, Michael R.
2014-01-01
Fieldwork in urban geography courses can encourage reflexivity among students regarding the cities they encounter. This article outlines how student reflexivity was encouraged within a new international field research course in Singapore and Malaysia. Drawing on examples from students' field exercises written during an intensive and…
Role of the asymmetrical tonic neck reflex in hand visualization in normal infants.
Coryell, J; Henderson, A
1979-04-01
Fourteen infants were each videotaped 7 times within the first 12 weeks of life to determine whether or not the asymmetrical tonic neck reflex had a role in placing their hands within their fields of vision. Infants' arms were more frequently out of the reflex position. Hands were within the peripheral visual field more often than in the focal visual field or not within the visual field. The proportion of observations that hands were in a particular visual field varied in accordance with the presence or absence of the reflex. A higher proportion of reflex observations occurred in the focal visual field, whereas a higher proportion of observations made when the infants were not in the reflex position occurred in the peripheral visual field. Further, the proportion of focal field observations in the reflex position was greater than the proportion of observations out of the reflex position for the first six of the seven ages. This study confirms that when infants are in the asymmetrical tonic neck reflex position, their hands are more likely to be in a position in which they can be visualized. PMID:443149
Habituation of the blink reflex in the neonatal period and development of auditory processing
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Tânia Tochetto
2011-03-01
Full Text Available Objective: To check the existence of an association between the presence/absence of the blink reflex habituation in the neonatal period and auditory processing development. Methods: The occurrence of blink reflex habituation was studied in 33 neurologically normal neonates, aged between 9 and 25 months, who had their behavioral responses analyzed and classified according to Azevedo (1993. Habituation of the blink reflex was verified using 90-dB sound stimulus. The stage of auditory processing development was evaluated through 41-dB sound stimulus. Statistical data were analyzed with Fischer and ?2 tests. Results: Out of the 33 studied children, 22 presented blink reflex habituation in the first stage of the study. In 7 of them, the auditory processing stage matched their chronological age, while in 15 of them the auditory processing stage was not in accordance with their chronological age. Eleven children failed to present habituation of the blink reflex in the first stage of the study. From this group, eight children presented auditory responses that were appropriate to their chronological age, whereas three had inappropriate responses. A statistically significant association between the presence of blink reflex habituation and auditory processing delay was verified, in addition to an association between the absence of the blink reflex habituation and chronologically suitable responses. Conclusions: The presence of blink reflex habituation in the neonatal period does not seem to be a predictive factor of suitable auditory processing.
McClean, Michael D.
1987-01-01
Surface electrodes were used to describe the perioral reflexes in seven stutterers and five nonstutterers and electromyographic (EMG) recordings were obtained at electrode sites associated with the orbicularis oris inferior muscle and the depressor labia inferior muscle. A difference was noted in the pattern of reflex response between the two…
Cutaneous inhibitory receptive fields of withdrawal reflexes in the decerebrate spinal rat.
Weng, H R; Schouenborg, J
1996-05-15
1. The inhibitory cutaneous input to the withdrawal reflex pathways to single hindlimb muscles was investigated in decerebrate spinal rats (n = 53) using electromyography. 2. Withdrawal reflexes in the peronei, extensor digitorum longus and tibialis anterior muscles of the leg were strongly inhibited by conditioning mechanical, thermal (CO2 laser) and intracutaneous electrical stimulation of specific skin areas. By contrast, withdrawal reflexes in the biceps posterior-semitendinosus muscles of the thigh could only be weakly inhibited by conditioning skin stimulation. 3. Powerful inhibition of withdrawal reflexes in single lower leg muscles was elicited from the ipsilateral hindpaw plantar area, which would move towards the stimulation on contraction in the respective muscle. In addition, weak nociceptive inhibition was evoked from the corresponding skin areas on the contralateral hindlimb and, in some muscles, the tail. 4. The ipsilateral inhibitory and excitatory receptive fields of the withdrawal reflexes in single muscles overlapped somewhat. On stimulation of these transitional areas the reflex responses were preceded by a short-lasting inhibition. 5. Graded mechanical and thermal stimulation demonstrated prominent inhibitors effects from nociceptive receptors. Weak inhibitory effects were elicited by innocuous mechanical stimulation, suggesting a weak contribution from low threshold mechanoreceptors. Latency measurements indicated an inhibitory input from both myelinated and unmyelinated fibres. 6. In conclusion, the withdrawal reflex pathways receive a powerful nociceptive inhibitory input through spinal pathways. The movement-related organization of this input suggests that it serves to prevent inappropriate withdrawal reflexes. PMID:8735710
Processing Reflexives in a Second Language: The Timing of Structural and Discourse-Level Constraints
Felser, Claudia; Cunnings, Ian
2012-01-01
We report the results from two eye-movement monitoring experiments examining the processing of reflexive pronouns by proficient German-speaking learners of second language (L2) English. Our results show that the nonnative speakers initially tried to link English argument reflexives to a discourse-prominent but structurally inaccessible antecedent,…