Sample records for complex symmetric linear

  1. The SCBiCG class of algorithms for complex symmetric linear systems with applications in several electromagnetic model problems

    NASA Astrophysics Data System (ADS)

    Gu, Xian-Ming; Clemens, Markus; Huang, Ting-Zhu; Li, Liang

    2015-06-01

    Frequency domain formulations of computational electromagnetic problems often require the solutions of complex-valued non-Hermitian systems of equations, which are still symmetric. For this kind of problems a whole class of sub-variant solver methods derived from the complex-valued Bi-Conjugate Gradient method is available. This class of methods contains established iterative methods as the Conjugate Orthogonal Conjugate Gradient (COCG) method, Bi-Conjugate Gradient Conjugate Residual (BiCGCR) method and Conjugate A-Orthogonal Conjugate Residual (COCR) method. The mathematical equivalence of the BiCGCR method and COCR method is shown and preconditioned variants of the various solvers are derived. An efficient kind of two-step preconditioning technique is also proposed. Numerical experiments involving e.g. electro-quasistatic frequency domain simulation are employed to show the difference in the convergence behaviors of these iterative methods and effectiveness of the two-step preconditioning techniques.

  2. Linearization Method and Linear Complexity

    NASA Astrophysics Data System (ADS)

    Tanaka, Hidema

    We focus on the relationship between the linearization method and linear complexity and show that the linearization method is another effective technique for calculating linear complexity. We analyze its effectiveness by comparing with the logic circuit method. We compare the relevant conditions and necessary computational cost with those of the Berlekamp-Massey algorithm and the Games-Chan algorithm. The significant property of a linearization method is that it needs no output sequence from a pseudo-random number generator (PRNG) because it calculates linear complexity using the algebraic expression of its algorithm. When a PRNG has n [bit] stages (registers or internal states), the necessary computational cost is smaller than O(2n). On the other hand, the Berlekamp-Massey algorithm needs O(N2) where N(?2n) denotes period. Since existing methods calculate using the output sequence, an initial value of PRNG influences a resultant value of linear complexity. Therefore, a linear complexity is generally given as an estimate value. On the other hand, a linearization method calculates from an algorithm of PRNG, it can determine the lower bound of linear complexity.

  3. Minimal Residual Methods for Complex Symmetric, Skew Symmetric ...

    E-print Network

    Sou-Cheng (Terrya) Choi

    2013-04-26

    Apr 26, 2013 ... three-term recurrent complex-symmetric Lanczos process. Whether the ... (1975) with enhanced stability and capability. Key words. .... k in subscripts or superscripts denote integer indices, otherwise they may represent. ?.

  4. PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS

    E-print Network

    PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS- tition complex, and identify it as the Tits building. This gives a homological relationship of equivalence relations on a finite set; a Tits building is a geometric object associated to the poset

  5. PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS

    E-print Network

    PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS G. Z. ARONE AND W. G. DWYER Abstract. We construct a homological approximation to the par- tition complex, and identify it as the Tits building on a finite set; a Tits building is a geometric object associated to the poset of subspaces of a vector space

  6. Symmetric nested complexes of fullerenes.

    PubMed

    Mar, Naveicy; Sansores, Luis Enrique; Muhl, Stephen; Ramos, Estrella; Salcedo, Roberto

    2015-04-01

    Large fullerenes such as C180 and C116 can be used as hosts for other molecules of the same family. Based on this idea, two complexes were designed, one in which C180 accepts a C60 molecule as a guest and the other in which C20 was placed inside C116. The behavior of these new assemblies was closer to that of a large endohedral complex rather than onion-like. There were marked differences between the systems. In the first system, there was minor interaction between the two cages but the association resulted in a more stable thermodynamic state. In the second system, there was strong electronic interchange between the cages, and the thermodynamic results suggest that such a combination might be useful for forming stable C20. PMID:25823391

  7. Irreducible complexity of iterated symmetric bimodal maps

    Microsoft Academic Search

    J. P. Lampreia; R. Severino; J. Sousa Ramos

    2004-01-01

    We introduce a tree structure for the iterates of symmetric bimodal maps and identify a subset which we prove to be isomorphic to the family of unimodal maps. This subset is used as a second factor for a $\\\\ast $-product that we define in the space of bimodal kneading sequences. Finally, we give some properties for this product and study

  8. Irreducible complexity of iterated symmetric bimodal maps

    E-print Network

    J. P. Lampreia; R. Severino; J. Sousa Ramos

    2004-03-08

    We introduce a tree structure for the iterates of symmetric bimodal maps and identify a subset which we prove to be isomorphic to the family of unimodal maps. This subset is used as a second factor for a $\\ast $-product that we define in the space of bimodal kneading sequences. Finally, we give some properties for this product and study the *-product induced on the associated Markov shifts.

  9. Irreducible complexity of iterated symmetric bimodal maps

    Microsoft Academic Search

    J. P. Lampreia; R. Severino; J. Sousa Ramos

    2004-01-01

    We introduce a tree structure for the iterates of symmetric bimodal maps and\\u000aidentify a subset which we prove to be isomorphic to the family of unimodal\\u000amaps. This subset is used as a second factor for a $\\\\ast $-product that we\\u000adefine in the space of bimodal kneading sequences. Finally, we give some\\u000aproperties for this product and study

  10. Left-symmetric Structures on Complex Simple Lie Superalgebras

    E-print Network

    Run-Xuan Zhang

    2013-02-23

    A well-known fact is that there does not exist any compatible left-symmetric structures on a finite-dimensional complex semisimple Lie algebra (see \\cite{Chu1974}). This result is not valid in semisimple Lie superalgebra case. In this paper, we study the compatible Left-symmetric superalgebra (LSSA for short) structures on complex simple Lie superalgebras. We prove that there is not any compatible LSSA structure on a finite-dimensional complex simple Lie superalgebra except for the classical simple Lie superalgebra $A(m,n)(m\

  11. The solitons in parity-time symmetric mixed Bessel linear potential and modulated nonlinear lattices

    NASA Astrophysics Data System (ADS)

    Chen, Haibo; Hu, Sumei

    2014-12-01

    The optical solitons in parity-time (PT) symmetric mixed Bessel linear potential and modulated nonlinear lattices are studied, including linear case, and self-focusing modulated nonlinear lattices' cases. For linear case, the PT-breaking points, the eigenvalues and eigenfunction for different modulated depths of PT symmetry Bessel complex potential, are obtained numerically. The eigenvalue for linear case is equal to the critical propagation constant bc of soliton existence. With increasing of the depth of the nonlinear lattices, the power of fundamental solitons decreases and the beam width changes little, but the power of multipole solitons increases and the beam width decreases. Fundamental solitons are stable in the whole region and multipole solitons are stable with the propagation constants close to bc. The range of multipole solitons stability decreases with increasing of the depth of the nonlinear lattices.

  12. The Complexity of Computing Symmetric Functions Using Threshold Circuits 1

    E-print Network

    Beame, Paul

    are an interesting class of circuits to study because of their relationship to neural networks [15] and perceptronsThe Complexity of Computing Symmetric Functions Using Threshold Circuits 1 Paul Beame Erik Brisson Revised 2/8/91 Abstract This paper considers size­depth tradeo#s for threshold circuits computing

  13. New Upper Bounds on the Boolean Circuit Complexity of Symmetric Functions

    E-print Network

    New Upper Bounds on the Boolean Circuit Complexity of Symmetric Functions E. Demenkova,1 , A on the circuit complexity of symmetric Boolean functions. In particular, we describe circuits of size 4.5n + o: Computational complexity, Boolean circuit complexity; Upper bounds; Symmetric functions; Modular functions 1

  14. Regulator problem for linear discrete-time systems with non-symmetrical constrained control

    Microsoft Academic Search

    ABDELLAH BENZAOUIA; CHRISTIAN BURGAT

    1988-01-01

    The regulator problem is studied for linear discrete-time systems with non-symmetrical constrained control, i.e. systems described by the state equation xk+1 = Axk + Buk, where uk ? ?, and uk = Fxk. Necessary and sufficient conditions allowing us to obtain the largest non-symmetrical polyhedral domain of positive invariance and contractivity with respect to motions of the system in the closed loop are established. The case of symmetrically

  15. A study of PT-symmetric Non-linear Schroedinger Equation

    E-print Network

    K. Nireekshan Reddy; Subhrajit Modak; Kumar Abhinav; Prasanta K. Panigrahi

    2015-05-20

    Systems governed by the Non-linear Schroedinger Equation (NLSE) with various external PT-symmetric potentials are considered. Exact solutions have been obtained for the same through the method of ansatz, some of them being solitonic in nature. It is found that only the unbroken PT-symmetric phase is realized in these systems, characterized by real energies.

  16. Bounds for axially symmetric linear perturbations for the extreme Kerr black hole

    E-print Network

    Sergio Dain; Ivan Gentile de Austria

    2015-01-15

    We obtain remarkably simple integral bounds for axially symmetric linear perturbations for the extreme Kerr black hole in terms of conserved energies. From these estimates we deduce pointwise bounds for the perturbations outside the horizon.

  17. Bounds for axially symmetric linear perturbations for the extreme Kerr black hole

    NASA Astrophysics Data System (ADS)

    Dain, Sergio; Gentile de Austria, Ivan

    2015-07-01

    We obtain remarkably simple integral bounds for axially symmetric linear perturbations for the extreme Kerr black hole in terms of conserved energies. From these estimates we deduce pointwise bounds for the perturbations outside the horizon.

  18. Symmetric matrices properties to duality in linear programming problem

    Microsoft Academic Search

    Ikhsan Romli; Taufik; Adi Saptari; Muzalna bt Mohd Jusoh

    2011-01-01

    Duality is one of the most important topics in optimization either a theoretical and algorithmic perspective. Optimization problem usually involved mathematical model. One of the applications widely used is Linear Programming. Linear functions applications are frequently used in production planning, networks, scheduling, and other application of a linear function subject to linear constraints. Extensive number of papers related with duality

  19. Solitons supported by complex PT-symmetric Gaussian potentials

    SciTech Connect

    Hu Sumei [Laboratory of Photonic Information Technology, South China Normal University, Guangzhou 510631 (China); Department of Physics, Guangdong University of Petrochemical Technology, Maoming 525000 (China); Ma Xuekai; Lu Daquan; Yang Zhenjun; Zheng Yizhou; Hu Wei [Laboratory of Photonic Information Technology, South China Normal University, Guangzhou 510631 (China)

    2011-10-15

    The existence and stability of fundamental, dipole, and tripole solitons in Kerr nonlinear media with parity-time-symmetric Gaussian complex potentials are reported. Fundamental solitons are stable not only in deep potentials but also in shallow potentials. Dipole and tripole solitons are stable only in deep potentials, and tripole solitons are stable in deeper potentials than for dipole solitons. The stable regions of solitons increase with increasing potential depth. The power of solitons increases with increasing propagation constant or decreasing modulation depth of the potentials.

  20. Solitons supported by complex PT symmetric Gaussian potentials

    E-print Network

    Hu, Sumei; Lu, Daquan; Yang, Zhenjun; Zheng, Yizhou; Hu, Wei

    2011-01-01

    The existence and stability of fundamental, dipole, and tripole solitons in Kerr nonlinear media with parity-time (PT) symmetric Gaussian complex potentials are reported. Fundamental solitons are stable not only in deep potentials but also in shallow potentials. Dipole and tripole solitons are stable only in deep potentials, and tripole solitons are stable in deeper potentials than that for dipole solitons. The stable regions of solitons increase with increasing of the potential depth. The power of solitons increases with increasing of propagation constant or decreasing of modulation depth of the potentials.

  1. Talbot self-imaging in PT-symmetric complex crystals

    NASA Astrophysics Data System (ADS)

    Longhi, Stefano

    2014-10-01

    The Talbot effect, i.e., the self-imaging property of a periodic wave in near-field diffraction, is a remarkable interference phenomenon in paraxial systems with continuous translational invariance. In crystals, i.e., systems with discrete translational invariance, self-imaging has been regarded so far as a rare effect, restricted to special sets of initial field distributions. Here it is shown that in a class of gapless PT-symmetric complex crystals at the symmetry-breaking threshold Talbot revivals can arise for almost any initial periodic wave distribution which is commensurate with the lattice period. A possible experimental realization of commensurate Talbot self-imaging for light pulses in complex "temporal" crystals, realized in an optical dispersive fiber loop with amplitude and phase modulators, is briefly discussed.

  2. Experimental beta limits of symmetric linear heliac configurations

    SciTech Connect

    Spanjers, G.G.; Nelson, B.A.; Ribe, F.L.; Jarboe, T.R. (120 AERL FL-10, University of Washington, Seattle, Washington 98195 (United States))

    1994-08-01

    Helically symmetric heliac equilibria [H. P. Furth, [ital Plasma] [ital Physics] [ital and] [ital Controlled] [ital Fusion] [ital Research] (International Atomic Energy Agency, Vienna, 1966), Vol. 1, p. 103] are formed on the High Beta Q Machine (HBQM) [C. M. Greenfield, Phys. Fluids B [bold 2], 133 (1990)] by using a fast-rising central conductor (hardcore) current in conjunction with a shock-heated [ital l]=1 stellarator configuration. The equilibria are found to possess a high global beta and the plasma pressure is approximately a flux-surface quantity. Under the effects of plasma, the magnetic well is found to deepen and the rotational transform is greatly increased and becomes highly sheared, owing to plasma currents induced by the fast-rising hardcore current. In the second phase of the experiment, the equilibrium fields of the symmetric heliac are lowered while maintaining the same shock heating in an attempt to raise the global beta. No substantial change in global beta is seen, indicating that the configuration forms at the beta limit in the shock-heated HBQM, and that the plasma beta seen in the first phase of the experiment is the symmetric heliac beta limit.

  3. On the linear stability of the extreme Kerr black hole under axially symmetric perturbations

    E-print Network

    Sergio Dain; Ivan Gentile de Austria

    2014-09-19

    We prove that for axially symmetric linear gravitational perturbations of the extreme Kerr black hole there exists a positive definite and conserved energy. This provides a basic criteria for linear stability in axial symmetry. In the particular case of Minkowski, using this energy we also prove pointwise boundedness of the perturbation in a remarkable simple way.

  4. Symmetrical and unsymmetrical dizinc complexes as models for the active sites of hydrolytic enzymes.

    PubMed

    Jarenmark, Martin; Kappen, Sascha; Haukka, Matti; Nordlander, Ebbe

    2008-02-28

    Dinuclear carboxylate-bridged zinc complexes of one symmetric and one asymmetric phenolate-based ligand catalyse the transesterification of 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) at different rates, with an unsymmetrical complex being more active than a symmetric one. PMID:18274677

  5. The Asymptotic Normalized Linear Complexity of Multisequences

    E-print Network

    Vielhaber, Michael

    2007-01-01

    We show that the asymptotic linear complexity of a multisequence a in F_q^\\infty that is I := liminf L_a(n)/n and S := limsup L_a(n)/n satisfy the inequalities M/(M+1) <= S <= 1 and M(1-S) <= I <= 1-S/M, if all M sequences have nonzero discrepancy infinitely often, and all pairs (I,S) satisfying these conditions are met by 2^{\\aleph_0} multisequences a. This answers an Open Problem by Dai, Imamura, and Yang. Keywords: Linear complexity, multisequence, Battery Discharge Model, isometry.

  6. Generation of Symmetric Dicke States of Remote Qubits with Linear Optics

    Microsoft Academic Search

    C. Thiel; J. von Zanthier; T. Bastin; E. Solano; G. S. Agarwal

    2007-01-01

    We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using linear optical tools only. By means of a suitable multiphoton detection technique, erasing Welcher-Weg information, our proposed scheme allows the generation and measurement of an important class of entangled

  7. Pseudo-radial solutions of semi-linear elliptic on symmetric domains

    E-print Network

    Paris-Sud XI, Université de

    Pseudo-radial solutions of semi-linear elliptic equations on symmetric domains Ahmad El Soufi and Mustapha Jazar Abstract In this paper we investigate existence and characterization of non-radial pseudo description of the set of pseudo-radial solutions of equations of the form u = ±a2 (|x|)u|u|q-1 , with q > 0

  8. The complexity of propositional linear temporal logics

    Microsoft Academic Search

    A. Prasad Sistla; Edmund M. Clarke

    1985-01-01

    The complexity of satisfiability and determination of truth in a particular finite structure are considered for different propositional linear temporal logics. It is shown that these problems are NP-complete for the logic with F and are PSPACE-complete for the logics with F, X, with U, with U, S, X operators and for the extended logic with regular operators given by

  9. Hilbert Function and Complexity Lower Bounds for Symmetric Boolean Functions

    Microsoft Academic Search

    Anna Bernasconi; Lavinia Egidi

    1999-01-01

    This paper explores the application of certain algebraic geometry techniques involving Hilbert functions and Gröbner bases to the analysis of properties of Boolean functions. It gives some results and applications for symmetric functions.

  10. Generation of Symmetric Dicke States of Remote Qubits with Linear Optics

    SciTech Connect

    Thiel, C.; Zanthier, J. von [Institut fuer Optik, Information und Photonik, Max-Planck Forschungsgruppe, Universitaet Erlangen-Nuernberg, 91058 Erlangen (Germany); Bastin, T. [Institut de Physique Nucleaire, Atomique et de Spectroscopie, Universite de Liege, 4000 Liege (Belgium); Solano, E. [Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado Postal 1761, Lima (Peru); Agarwal, G. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078-3072 (United States)

    2007-11-09

    We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using linear optical tools only. By means of a suitable multiphoton detection technique, erasing Welcher-Weg information, our proposed scheme allows the generation and measurement of an important class of entangled multiqubit states.

  11. Trellis Decoding Complexity of Linear Block Codes

    NASA Technical Reports Server (NTRS)

    Kiely, A. B.; McEliece, R. J.; Lin, W.; Ekroot, L.; Dolinar, S.

    1995-01-01

    We consider the problem of finding a trellis for a linear block code that minimizes one or more measures of trellis complexity. The domain of optimization may be different permutations of the same code, or different codes with the same parameters. Constraints on trellises, including relationships between the minimal trellis of a code and that of the dual code, are used to derive bounds on complexity. We define a partial ordering on trellises: if a trellis is optimum with respect to this partial ordering, it has the desirable property that it simultaneously minimizes all of the complexity measures examined. We examine properties of such optimal trellises and give examples of optimal permutations of codes, most notably the (48,24,12) quadratic residue code.

  12. Symmetric periodic solutions of semi-linear wave equations on S{sup 3}

    SciTech Connect

    Zhao, Xin-Ming; Zhou, Zhengfang [Michigan State Univ., East Lansing, MI (United States)

    1996-12-31

    This paper is primarily concerned with the regularity and the existence of symmetric and periodic solutions of the semi-linear wave equation on S{sup 3} u{sub tt}-{Delta}u+u+F(t,x,u)=0 in S{sup 1} x S{sup 3}, where {Delta} is the Laplace-Beltrami operator on S{sup 3}. Under various conditions on function F, the existence results for semi-linear wave equation on S{sup 1} x S{sup n} are obtained by many authors, e.g., Benci and Fortunato, Brezis and Nirenberg, Rabinowitz and Zhou, among others. The regularity results in the case of n=1 are obtained by Brezis and Nirenberg for asymptotically linear F and by Rabinowitz for super-linear F. Jerison, Sogge and Zhou studied and proved the regularity results for n = 2, n = 4 and n = 6. 15 refs.

  13. On the linear equation method for the subduction problem in symmetric groups

    NASA Astrophysics Data System (ADS)

    Chilla, Vincenzo

    2006-06-01

    We focus on the transformation matrices between the standard Young-Yamanouchi basis of an irreducible representation for the symmetric group Sn and the split basis adapted to the direct product subgroups S_{n_1} \\times S_{n-n_1} . We introduce the concept of subduction graph and show that it conveniently describes the combinatorial structure of the equation system arisen from the linear equation method. Thus we can outline an improved algorithm to solve the subduction problem in symmetric groups by a graph searching process. We conclude by observing that the general matrix form for multiplicity separations, resulting from orthonormalization, can be expressed in terms of Sylvester matrices relative to a suitable inner product in the multiplicity space.

  14. Preconditioning the bidomain model with almost linear complexity

    NASA Astrophysics Data System (ADS)

    Pierre, Charles

    2012-01-01

    The bidomain model is widely used in electro-cardiology to simulate spreading of excitation in the myocardium and electrocardiograms. It consists of a system of two parabolic reaction diffusion equations coupled with an ODE system. Its discretisation displays an ill-conditioned system matrix to be inverted at each time step: simulations based on the bidomain model therefore are associated with high computational costs. In this paper we propose a preconditioning for the bidomain model either for an isolated heart or in an extended framework including a coupling with the surrounding tissues (the torso). The preconditioning is based on a formulation of the discrete problem that is shown to be symmetric positive semi-definite. A block LU decomposition of the system together with a heuristic approximation (referred to as the monodomain approximation) are the key ingredients for the preconditioning definition. Numerical results are provided for two test cases: a 2D test case on a realistic slice of the thorax based on a segmented heart medical image geometry, a 3D test case involving a small cubic slab of tissue with orthotropic anisotropy. The analysis of the resulting computational cost (both in terms of CPU time and of iteration number) shows an almost linear complexity with the problem size, i.e. of type nlog ?( n) (for some constant ?) which is optimal complexity for such problems.

  15. A unidirectional invisible PT-symmetric complex crystal with arbitrary thickness

    E-print Network

    Stefano Longhi

    2014-10-20

    We introduce a new class of $\\mathcal{PT}$-symmetric complex crystals which are almost transparent and one-way reflectionless over a broad frequency range around the Bragg frequency, i.e. unidirectionally invisible, regardless of the thickness $L$ of the crystal. The $\\mathcal{PT}$-symmetric complex crystal is synthesized by a supersymmetric transformation of an Hermitian square well potential, and exact analytical expressions of transmission and reflection coefficients are given. As $L$ is increased, the transmittance and reflectance from one side remain close to one and zero, respectively, whereas the reflectance from the other side secularly grows like $ \\sim L^2$ owing to unidirectional Bragg scattering. This is a distinctive feature as compared to the previously studied case of the complex sinusoidal $\\mathcal{PT}$-symmetric potential $V(x)=V_0 \\exp(-2i k_ox)$ at the symmetry breaking point, where transparency breaks down as $L \\rightarrow \\infty$.

  16. BER optimal linear combiner for signal detection in symmetric alpha-stable noise: small values of alpha

    Microsoft Academic Search

    S. Niranjayan; Norman C. Beaulieu

    2010-01-01

    The maximum likelihood optimal combiner for signal detection in alpha-stable noise is not known in general, except for some special values of the characteristic exponent ¿. A linear Rake combiner receiver is simple and easy to realize. The optimal linear Rake receiver, in the sense of minimizing the bit error rate, for the detection of signals contaminated by symmetric alpha

  17. New algorithm for modulated complex lapped transform with symmetrical window function

    Microsoft Academic Search

    Qionghai Dai; Xinjian Chen

    2004-01-01

    An algorithm for the fast computation of modulated complex lapped transform (MCLT) with symmetrical window function is proposed. The method is based on two discrete cosine transforms (DCTs), two stages of butterfly operations and additional multiplications. The real or imaginary part of the MCLT coefficients can be independently obtained from one of the two blocks of DCT coefficients. The proposed

  18. A Symmetrical Tetramer for S. aureus Pyruvate Carboxylase in Complex with Coenzyme A

    E-print Network

    Tong, Liang

    Structure Article A Symmetrical Tetramer for S. aureus Pyruvate Carboxylase in Complex@columbia.edu DOI 10.1016/j.str.2009.04.008 SUMMARY Pyruvate carboxylase (PC) is a conserved metabolic enzyme more competent. INTRODUCTION Pyruvate carboxylase (PC, EC 6.4.1.1) is a biotin-dependent enzyme

  19. Split Register Allocation: Linear Complexity Without the Performance Penalty

    E-print Network

    Paris-Sud XI, Université de

    Split Register Allocation: Linear Complexity Without the Performance Penalty Boubacar Diouf,1 a limited set of hot functions for ag- gressive optimization. To date, (quasi-)linear complexity has remained a driving force in the design of just-in-time optimizers. This paper describes a split register

  20. AVERAGE CASE COMPLEXITY OF LINEAR MULTIVARIATE PROBLEMS

    E-print Network

    multivariate problems LMP equipped with the folded Wiener sheet measure. We are particularly interested in multivariate weighted integration and multivariate function approximation. We prove that any LMP which in \\Lambda std . 1. Introduction In this part we study linear multivariate problems LMP which are equipped

  1. A Shared and Programmable Maximum-Confident Discrimination among Linearly Dependent Symmetric Qubit States

    NASA Astrophysics Data System (ADS)

    Chen, LiBing; Lu, Hong

    2015-06-01

    We show how a shared and programmable maximum-confidence discrimination (SPMCD) can be implemented by two remote parters Alice and Bob. Here Bob is given a qubit prepared in one of N linearly dependent symmetric equiprobable states. Alice has the knowledge of Bob's signal states, but Bob has not. We build a quantum network that would be able to perform various desired maximum-confidence discrimination among Bob's measured (data) states depending on Alice's auxiliary (program) state. The SPMCD can be thought of as a two-step process, in which a two-outcome shared and programmable probability operator measure (POM) performed on data qubit B is firstly implemented by Alice and Bob followed by a N-outcome local POM on B implemented by Bob. We explicitly construct the required POMs. The fact that the nonlocal data-program conditional evolution, which induces the shared and programmable POM, can be realized deterministically using only two partially entangled qubit pairs is notable. The successful probability of implementing this SPMCD is optimal only for one program setting. However, for a relatively large set of program settings it can be very close to the optimal value in an ordinary, local, maximum-confidence discrimination. This protocol is feasible for current experimental technology.

  2. Collision-induced absorption in mixtures of symmetrical linear and tetrahedral molecules - Methane-nitrogen

    NASA Technical Reports Server (NTRS)

    Birnbaum, G.; Borysow, A.; Buechele, A.

    1993-01-01

    The far infrared absorption of a CH4-N2 mixture was measured at 297, 195, and 162 K from 30 to 650/cm. The spectral invariants gamma1 and alpha1, proportional, respectively, to the zeroth and first spectral moments, due to bimolecular collisions between CH4 and N2 were obtained from these data and compared with theoretical values. The theory for collision-induced dipoles between a tetrahedral and a diatomic or symmetrical linear molecule includes contributions not previously considered. Whereas the theoretical values of gamma1 are only somewhat greater than experiment at all temperatures, the theoretical values of alpha1 are significantly lower than the experimental values. From the theoretical spectral moments for the various induced dipole components, the parameters of the BC shape were computed, and theoretical spectra were constructed. Good agreement was obtained at the lower frequencies, but with increasing frequencies the theoretical spectra were increasingly less intense than the experimental spectra. Although the accuracy of the theoretical results may suffer from the lack of a reliable potential function, it does not appear that this high frequency discrepancy can be removed by any conceivable modification in the potential.

  3. The linear complexity of the self-shrinking generator

    Microsoft Academic Search

    Simon R. Blackburn

    1999-01-01

    The self-shrinking generator, a stream cipher due to Meier and Staffelbach, uses the output of a primitive binary linear-feedback shift register (LFSR) of length to generate a keystream sequence of period dividing . The article proves that the linear complexity of the keystream is at most

  4. DIMACS Technical Report 9936 Randomized Complexity of Linear

    E-print Network

    DIMACS Technical Report 99­36 Randomized Complexity of Linear Arrangements and Polyhedra by Marek several open problems and possible directions for future research. #12; 1 Introduction. Linear search algorithms, algebraic decision trees, and computation trees were introduced early to simulate random access

  5. Eigenvalue problems for the complex PT-symmetric potential V(x)= igx

    E-print Network

    Zafar Ahmed

    2006-11-21

    The spectrum of complex PT-symmetric potential, $V(x)=igx$, is known to be null. We enclose this potential in a hard-box: $V(|x| \\ge 1) =\\infty $ and in a soft-box: $V(|x|\\ge 1)=0$. In the former case, we find real discrete spectrum and the exceptional points of the potential. The asymptotic eigenvalues behave as $E_n \\sim n^2.$ The solvable purely imaginary PT-symmetric potentials vanishing asymptotically known so far do not have real discrete spectrum. Our solvable soft-box potential possesses two real negative discrete eigenvalues if $|g|<(1.22330447)$. The soft-box potential turns out to be a scattering potential not possessing reflectionless states.

  6. A variant of the linear isotropic indeterminate couple stress model with symmetric local force-stress, symmetric nonlocal force-stress, symmetric couple-stresses and complete traction boundary conditions

    E-print Network

    Ionel-Dumitrel Ghiba; Patrizio Neff; Angela Madeo; Ingo Münch

    2015-04-03

    In this paper we venture a new look at the linear isotropic indeterminate couple stress model in the general framework of second gradient elasticity and we propose a new alternative formulation which obeys Cauchy-Boltzmann's axiom of the symmetry of the force stress tensor. For this model we prove the existence of solutions for the equilibrium problem. Relations with other gradient elastic theories and the possibility to switch from a {4th order} (gradient elastic) problem to a 2nd order micromorphic model are also discussed with a view of obtaining symmetric force-stress tensors. It is shown that the indeterminate couple stress model can be written entirely with symmetric force-stress and symmetric couple-stress. The difference of the alternative models rests in specifying traction boundary conditions of either rotational type or strain type. If rotational type boundary conditions are used in the partial integration, the classical anti-symmetric nonlocal force stress tensor formulation is obtained. Otherwise, the difference in both formulations is only a divergence--free second order stress field such that the field equations are the same, but the traction boundary conditions are different. For these results we employ a novel integrability condition, connecting the infinitesimal continuum rotation and the infinitesimal continuum strain. Moreover, we provide the complete, consistent traction boundary conditions for both models.

  7. A Family of Symmetric Linear Multistep Methods for the Numerical Solution of the Schroedinger Equation and Related Problems

    SciTech Connect

    Anastassi, Z. A. [Department of Finance and Auditing, School of Management and Economics, Technological Educational Institute of Kalamata, GR-241 00 Antikalamos (Greece); Simos, T. E. [Laboratory of Computational Sciences, Department of Computer Science and Technology, Faculty of Sciences and Technology, University of Peloponnese, GR-22 100 Tripolis (Greece)

    2010-09-30

    We develop a new family of explicit symmetric linear multistep methods for the efficient numerical solution of the Schroedinger equation and related problems with oscillatory solution. The new methods are trigonometrically fitted and have improved intervals of periodicity as compared to the corresponding classical method with constant coefficients and other methods from the literature. We also apply the methods along with other known methods to real periodic problems, in order to measure their efficiency.

  8. A Symmetrical Tetramer for S. aureus Pyruvate Carboxylase in Complex with Coenzyme A

    SciTech Connect

    Yu, L.; Xiang, S; Lasso, G; Gil, D; Valle, M; Tong, L

    2009-01-01

    Pyruvate carboxylase (PC) is a conserved metabolic enzyme with important cellular functions. We report crystallographic and cryo-electron microscopy (EM) studies of Staphylococcus aureus PC (SaPC) in complex with acetyl-CoA, an allosteric activator, and mutagenesis, biochemical, and structural studies of the biotin binding site of its carboxyltransferase (CT) domain. The disease-causing A610T mutation abolishes catalytic activity by blocking biotin binding to the CT active site, and Thr908 might play a catalytic role in the CT reaction. The crystal structure of SaPC in complex with CoA reveals a symmetrical tetramer, with one CoA molecule bound to each monomer, and cryo-EM studies confirm the symmetrical nature of the tetramer. These observations are in sharp contrast to the highly asymmetrical tetramer of Rhizobium etli PC in complex with ethyl-CoA. Our structural information suggests that acetyl-CoA promotes a conformation for the dimer of the biotin carboxylase domain of PC that might be catalytically more competent.

  9. Zero width resonance (spectral singularity) in a complex PT-symmetric potential

    E-print Network

    Zafar Ahmed

    2009-08-20

    We show that the complex PT-Symmetric potential, $V(x)=-V_1 {sech}^2x + iV_2 {sech}x ~\\tanh x, $, entails a single zero-width resonance (spectral singularity) when $V_1+|V_2|=4n^2+4n+{3\\over 4}(n=1,2,3.., |V_2|>|V_1|+ {{sgn}(V_1) \\over 4})$ and the positive resonant energy is given as $E_*={1 \\over 4}[|V_2|-(1/4+V_1)]$.

  10. Reducing the parallel complexity of certain linear programming problems

    Microsoft Academic Search

    Pravin M. Vaidya

    1990-01-01

    The parallel complexity of solving linear programming problems is studied in the context of interior point methods. If n and m, respectively, denote the number of variables and the number of constraints in the given problem, an algorithm that solves linear programming problems in O((mn)1\\/4 (log 1 n)3L) time using O(M(n)m\\/n+1n3 ) processors is given. (M(n) is the number of

  11. Simulation of linear polymer melts in transient complex flow

    E-print Network

    Wapperom, Peter

    Simulation of linear polymer melts in transient complex flow P. Wapperom, R. Keunings CESAME into the numerical framework of Lagrangian par- ticle methods, developed previously to simulate dilute polymer of entangled polymers like polymer melts and concentrated solutions. The theory is based on the conceptually

  12. Solving the GPS Problem in Almost Linear Complexity

    E-print Network

    California at Berkeley, University of

    Solving the GPS Problem in Almost Linear Complexity Speaker: Shamgar Gurevich, UW Madison. Abstract (GPS) was built to ful...ll this task. It works as follows: Satellites send to earth their location. For simplicity, the Figure 1: Satellites communicate location in GPS. location of a satellite is a bit b 2 f 1g

  13. Non-linear radial accretion of an ideal gas onto a spherically symmetric black hole

    NASA Astrophysics Data System (ADS)

    Gracia-Linares, M.; Guzmán, F. S.; Lora-Clavijo, F. D.

    2013-07-01

    We solve numerically the Einstein-Euler system of equations for a perfect fluid with an ideal gas equation of state, moving radially toward a spherically symmetric black hole. In order to do so we use the 3+1 decomposition of space-time with the ADM formulation of general relativity. In particular we study the growth of the event horizon and verify the convergence of our code.

  14. Malachite green mediates homodimerization of antibody VL domains to form a fluorescent ternary complex with singular symmetric interfaces

    PubMed Central

    Szent-Gyorgyi, Chris; Stanfield, Robyn L.; Andreko, Susan; Dempsey, Alison; Ahmed, Mushtaq; Capek, Sara; Waggoner, Alan; Wilson, Ian A.; Bruchez, Marcel P.

    2013-01-01

    We report that a symmetric small molecule ligand mediates the assembly of antibody light chain variable domains (VLs) into a correspondent symmetric ternary complex with novel interfaces. The L5* Fluorogen Activating Protein (FAP) is a VL domain that binds malachite green dye (MG) to activate intense fluorescence. Crystallography of liganded L5* reveals a 2:1 protein:ligand complex with inclusive C2 symmetry, where MG is almost entirely encapsulated between an antiparallel arrangement of the two VL domains. Unliganded L5* VL domains crystallize as a similar antiparallel VL/VL homodimer. The complementarity determining regions (CDRs) are spatially oriented to form novel VL/VL and VL/ligand interfaces that tightly constrain a propeller conformer of MG. Binding equilibrium analysis suggests highly cooperative assembly to form a very stable VL/MG/VL complex, such that MG behaves as a strong chemical inducer of dimerization. Fusion of two VL domains into a single protein tightens MG binding over 1,000-fold to low picomolar affinity without altering the large binding enthalpy, suggesting that bonding interactions with ligand and restriction of domain movements make independent contributions to binding. Fluorescence activation of a symmetrical fluorogen provides a selection mechanism for the isolation and directed evolution of ternary complexes where unnatural symmetric binding interfaces are favored over canonical antibody interfaces. As exemplified by L5*, these self-reporting complexes may be useful as modulators of protein association or as high affinity protein tags and capture reagents. PMID:23978698

  15. Chaperonin-Assisted Protein Folding: Relative Population of Asymmetric and Symmetric GroEL:GroES Complexes.

    PubMed

    Haldar, Shubhasis; Gupta, Amit J; Yan, Xiao; Mili?i?, Goran; Hartl, F Ulrich; Hayer-Hartl, Manajit

    2015-06-19

    The chaperonin GroEL, a cylindrical complex consisting of two stacked heptameric rings, and its lid-like cofactor GroES form a nano-cage in which a single polypeptide chain is transiently enclosed and allowed to fold unimpaired by aggregation. GroEL and GroES undergo an ATP-regulated interaction cycle that serves to close and open the folding cage. Recent reports suggest that the presence of non-native substrate protein alters the GroEL/ES reaction by shifting it from asymmetric to symmetric complexes. In the asymmetric reaction mode, only one ring of GroEL is GroES bound and the two rings function sequentially, coupled by negative allostery. In the symmetric mode, both GroEL rings are GroES bound and are folding active simultaneously. Here, we find that the results of assays based on fluorescence resonance energy transfer recently used to quantify symmetric complexes depend strongly on the fluorophore pair used. We therefore developed a novel assay based on fluorescence cross-correlation spectroscopy to accurately measure GroEL:GroES stoichiometry. This assay avoids fluorophore labeling of GroEL and the use of GroEL cysteine mutants. Our results show that symmetric GroEL:GroES2 complexes are substantially populated only in the presence of non-foldable model proteins, such as ?-lactalbumin and ?-casein, which "over-stimulate" the GroEL ATPase and uncouple the negative GroEL inter-ring allostery. In contrast, asymmetric complexes are dominant both in the absence of substrate and in the presence of foldable substrate proteins. Moreover, uncoupling of the GroEL rings and formation of symmetric GroEL:GroES2 complexes is suppressed at physiological ATP:ADP concentration. We conclude that the asymmetric GroEL:GroES complex represents the main folding active form of the chaperonin. PMID:25912285

  16. Near consensus complex linear and nonlinear social networks

    NASA Astrophysics Data System (ADS)

    Ling, Bingo Wing-Kuen; Ho, Charlotte Yuk-Fan; Wang, Lidong; Teo, Kok-Lay; Tse, Chi K.; Dai, Qingyun

    2014-05-01

    Some of the nodes of complex social networks may support for a given proposal, while the rest of the nodes may be against the given proposal. Even though all the nodes support for or are against the given proposal, the decision certitudes of individual nodes may be different. In this case, the steady state values of the decision certitudes of the majority of the nodes are either higher than or lower than a threshold value. Deriving the near consensus property is a key to the analysis of the behaviors of complex social networks. So far, no result on the behaviors of the complex social networks satisfying the near consensus property has been reported. Hence, it is useful to extend the definition of the exact consensus property to that of a near consensus property and investigate the behaviors of the complex social networks satisfying the near consensus property. This paper extends the definition of exact consensus complex social networks to that of near consensus complex social networks. For complex linear social networks, this paper investigates the relationships among the vectors representing the steady state values of the decision certitudes of the nodes, the influence weight matrix and the set of vectors representing the initial state values of the decision certitudes of the nodes under a given near consensus specification. The above analysis is based on the Eigen theory. For complex nonlinear social networks with certain types of nonlinearities, the relationship between the influence weight matrix and the vectors representing the steady state values of the decision certitudes of the nodes is studied. When a complex nonlinear social network does not achieve the exact consensus property, the optimal near consensus condition that the complex social network can achieve is derived. This problem is formulated as an optimization problem. The total number of nodes that the decision certitudes of the nodes are either higher than or lower than a threshold value is maximized subject to the corresponding near consensus specification. The optimization problem is a nonsmooth optimization problem. The nonsmooth constraints are first approximated by smooth constraints. Then, the approximated optimization problem is solved via a conventional smooth optimization approach. Computer numerical simulation results as well as the comparisons of the behaviors of complex nonlinear social networks to those of the complex linear social networks are presented. The obtained results demonstrate that some complex social networks can satisfy the near consensus property but not the exact consensus property. Also, the conditions for the near consensus property are dependent on the types of nonlinearities, the influence weight matrix and the vectors representing the initial state values of the decision certitudes of the nodes.

  17. Charge-transfer complexes of some linear conjugated polyenes.

    PubMed Central

    Mallik, B; Jain, K M; Misra, T N

    1980-01-01

    On adsorption of some electron-acceptor molecules on the solid films of all-trans-beta-carotene, beta-apo-8'-carotenal, astacene and methylbixin a new absorption band appears on the longer-wavelength side of the spectrum in addition to the original bands. The position of this new band is dependent on the electron affinity (EA) of the acceptor molecules, and the intensity of this band increases with the amount of adsorbed acceptor molecules. A linear relationship between the vmax. of the new band and EA was observed. The value of the ionization potential of the polyenes estimated from such linear relationship agrees satisfactorily with the value obtained by other methods. It has been concluded that the polyenes behave as electron donor and first form molecular charge-transfer complexes (of type [polyene . I2] with iodine) with electron acceptors, these finally dissociating to yield ionic complexes (of type [polyene . I+] with iodine). PMID:7213346

  18. A criterion for the reality of the spectrum of PT symmetric Schroedinger operators with complex-valued periodic potentials

    E-print Network

    E. Caliceti; S. Graffi

    2008-04-29

    Consider in $L^2(\\R)$ the \\Sc operator family $H(g):=-d^2_x+V_g(x)$ depending on the real parameter $g$, where $V_g(x)$ is a complex-valued but $PT$ symmetric periodic potential. An explicit condition on $V$ is obtained which ensures that the spectrum of $H(g)$ is purely real and band shaped; furthermore, a further condition is obtained which ensures that the spectrum contains at least a pair of complex analytic arcs.

  19. Trellis complexity bounds for decoding linear block codes

    NASA Technical Reports Server (NTRS)

    Kiely, A. B.; Dolinar, S.; Ekroot, L.; Mceliece, R. J.; Lin, W.

    1995-01-01

    We consider the problem of finding a trellis for a linear block code that minimizes one or more measures of trellis complexity. The domain of optimization may be different permutations of the same code or different codes with the same parameters. Constraints on trellises, including relationships between the minimal trellis of a code and that of the dual code, are used to derive bounds on complexity. We define a partial ordering on trellises: If a trellis is optimum with respect to this partial ordering, if has the desirable property that it simultaneously minimizes all of the complexity measures examined. We examine properties of such optimal trellises and give examples of optimal permutations of codes, most notably the (48,24,12) quadratic residue code.

  20. Complexity of necessary efficiency in interval linear programming and multiobjective linear programming

    Microsoft Academic Search

    Milan Hladík

    We present some complexity results on checking necessary efficiency in interval multiobjective linear programming. Supposing\\u000a that objective function coefficients perturb within prescribed intervals, a feasible point x* is called necessarily efficient if it is efficient for all instances of interval data. We show that the problem of checking\\u000a necessary efficiency is co-NP-complete even for the case of only one objective.

  1. Branched-linear polyion complexes investigated by Monte Carlo simulations.

    PubMed

    Angelescu, Daniel G; Linse, Per

    2014-08-28

    Complexes formed by one charged and branched copolymer with an oppositely charged and linear polyion have been investigated by Monte Carlo simulations. A coarse-grained description has been used, in which the main chain of the branched polyion and the linear polyion possess the same absolute charge and charge density. The spatial extension and other structural properties, such as bond-angle orientational correlation function, asphericity, and scaling analysis of formed complexes, at varying branching density and side-chain length of the branched polyion, have been explored. In particular, the balance between cohesive Coulomb attraction and side-chain repulsions resulted in two main structures of a polyion complex. These structures are (i) a globular polyion core surrounded by side chains appearing at low branching density and (ii) an extended polyion core with side chains still being expelled at high branching density. The globule-to-extended transition occurred at a crossover branching density being practically independent of the side chain length. PMID:24999910

  2. Infinitely many solutions to a linearly coupled Schrödinger system with non-symmetric potentials

    NASA Astrophysics Data System (ADS)

    Wang, Chunhua; Yang, Jing

    2015-05-01

    We study a linearly coupled Schrödinger system in ?N(N ? 3). Assume that the potentials in the system are continuous functions satisfying suitable decay assumptions, but without any symmetry properties, and the parameters in the system satisfy some suitable restrictions. Using the Liapunov-Schmidt reduction methods two times and combining localized energy method, we prove that the problem has infinitely many positive synchronized solutions, which extends result Theorem 1.2 about nonlinearly coupled Schrödinger equations in Ao and Wei [Calculus Var. Partial Differ. Equations 51, 761-798 (2014)] to our linearly coupled problem.

  3. Adaptive Multiresolution and Dedicated Elastic Matching in Linear Time Complexity for Time Series Data Mining

    E-print Network

    Paris-Sud XI, Université de

    Adaptive Multiresolution and Dedicated Elastic Matching in Linear Time Complexity for Time Series multiresolution approach to the problem of multidimensional time series characterization. Furthermore we provide theoretically and experimentally that our multiresolution decomposition of times series has a linear complexity

  4. Complex linear effective theory and supersymmetry breaking vacua

    NASA Astrophysics Data System (ADS)

    Farakos, Fotis; von Unge, Rikard

    2015-02-01

    We calculate the low-energy effective action of massless and massive complex linear superfields coupled to a massive U(1) vector multiplet. Our calculations include superspace higher-derivative corrections and therefore go beyond previous results. Among the superspace higher derivatives, we find that terms that lead to a deformation of the auxiliary field potential and may break supersymmetry are also generated. We show that the supersymmetry breaking vacua can only be trusted if there exists a hierarchy between the higher-order terms. A renormalization group analysis shows that generically a hierarchy is not generated by the quantum corrections.

  5. Trajectories of probe spheres in generalized linear viscoelastic complex fluids.

    PubMed

    Khan, Manas; Mason, Thomas G

    2014-12-01

    We have developed a fast simulation that generates a random walk of an isolated probe sphere in a generalized linear viscoelastic complex fluid over a highly extended dynamic range. We introduce a coupled harmonically bound Brownian particle (c-HBBP) model, in which the relaxation modes of the viscoelastic medium are treated as harmonic wells. These wells are coupled to the probe sphere and perform Brownian motion in bound harmonic potentials corresponding to the next-longer relaxation mode, according to the relaxation spectrum of the viscoelastic material. We implement this c-HBBP model by generating variable temporal step sizes that have a uniform distribution in logarithmic time. We create and analyze trajectories for several different viscoelastic complex fluids: a polymer system at its gel point, a dense emulsion system, a blend of two monodisperse polystyrene polymers for which the relaxation spectrum has been measured, and a model anisotropic soft system that shows dense emulsion-like and gel-point behaviors along two orthogonal directions. Except for unusual viscoelastic materials, such as the polymer system at its gel point, the generated trajectories are neither self-similar nor self-affine. The resulting mean square displacements predicted by the c-HBBP model are consistent with the single-particle generalized Stokes-Einstein relation of linear passive microrheology. PMID:25259775

  6. Extending the eigCG algorithm to non-symmetric linear systems with multiple right-hand sides

    SciTech Connect

    Abdou Abdel-Rehim, Kostas Orginos, Andreas Stathopoulos

    2009-11-01

    For Hermitian positive definite linear systems and eigenvalue problems, the eigCG algorithm is a memory efficient algorithm that solves the linear system and simultaneously computes some of its eigenvalues. The algorithm is based on the Conjugate-Gradient (CG) algorithm, however, it uses only a window of the vectors generated by the CG algorithm to compute approximate eigenvalues. The number and accuracy of the eigenvectors can be increased by solving more right-hand sides. For Hermitian systems with multiple right-hand sides, the computed eigenvectors can be used to speed up the solution of subsequent systems. The algorithm was tested on Lattice QCD problems by solving the normal equations and was shown to give large speed up factors and to remove the critical slowing down as we approach light quark masses. Here, an extension to the non-symmetric case based on the two-sided Lanczos algorithm is given. The new algorithm is tested on Lattice QCD problems and is shown to give promising results. We also study the removal of the critical slowing down and compare results with those of the eigCG algorithm. We also discuss the case when the system is gamma5-Hermitian.

  7. On the experimental verification of quantum complexity in linear optics

    NASA Astrophysics Data System (ADS)

    Carolan, Jacques; Meinecke, Jasmin D. A.; Shadbolt, Peter J.; Russell, Nicholas J.; Ismail, Nur; Wörhoff, Kerstin; Rudolph, Terry; Thompson, Mark G.; O'Brien, Jeremy L.; Matthews, Jonathan C. F.; Laing, Anthony

    2014-08-01

    Quantum computers promise to solve certain problems that are forever intractable to classical computers. The first of these devices are likely to tackle bespoke problems suited to their own particular physical capabilities. Sampling the probability distribution from many bosons interfering quantum-mechanically is conjectured to be intractable to a classical computer but solvable with photons in linear optics. However, the complexity of this type of problem means its solution is mathematically unverifiable, so the task of establishing successful operation becomes one of gathering sufficiently convincing circumstantial or experimental evidence. Here, we develop scalable methods to experimentally establish correct operation for this class of computation, which we implement for three, four and five photons in integrated optical circuits, on Hilbert spaces of up to 50,000 dimensions. Our broad approach is practical for all quantum computational architectures where formal verification methods for quantum algorithms are either intractable or unknown.

  8. Implementation of Simplicial Complexes for CPA functions in C++11 using the Armadillo Linear Algebra Library

    E-print Network

    Hafstein, Sigurður Freyr

    Implementation of Simplicial Complexes for CPA functions in C++11 using the Armadillo Linear linear, nonlinear system, triangulation, simplicial complex, C++11, Armadillo linear algebra library to manipulate CPA functions for these purposes and discuss their implementation in C++11 using the Armadillo

  9. Detecting internally symmetric protein structures

    Microsoft Academic Search

    Changhoon Kim; Jodi Basner; Byungkook Lee

    2010-01-01

    BACKGROUND: Many functional proteins have a symmetric structure. Most of these are multimeric complexes, which are made of non-symmetric monomers arranged in a symmetric manner. However, there are also a large number of proteins that have a symmetric structure in the monomeric state. These internally symmetric proteins are interesting objects from the point of view of their folding, function, and

  10. Conventional quantum phase transition driven by a complex parameter in a non-Hermitian PT-symmetric Ising model

    NASA Astrophysics Data System (ADS)

    Li, C.; Zhang, G.; Zhang, X. Z.; Song, Z.

    2014-07-01

    A conventional quantum phase transition (QPT) can be accessed by varying a real parameter at absolute zero temperature. Motivated by the discovery of the pseudo-Hermiticity of non-Hermitian systems, we explore the QPT in the non-Hermitian PT-symmetric Ising model, which is driven by a staggered complex transverse field. Exact solution shows that the Laplacian of the ground-state energy density, with respect to real and imaginary components of the transverse field, diverges on the boundary in the complex plane. The phase diagram indicates that the imaginary transverse field has the effect of shrinking the paramagnetic phase. In addition, we also investigate the connection between the geometric phase and the QPT.

  11. Spreading of infectious diseases on complex networks with non-symmetric transmission probabilities

    E-print Network

    Britta Daudert; Bai-Lian Li

    2006-11-23

    We model the spread of a SIS infection on Small World and random networks using weighted graphs. The entry $w_{ij}$ in the weight matrix W holds information about the transmission probability along the edge joining node $v_i$ and node $v_j$. We use the analogy between the spread of a disease on a network and a random walk performed on this network to derive a master equation describing the dynamics of the process. We find conditions under which an epidemic does not break out and investigate numerically the effect of a non-symmetric weight distribution of the initially infected individual on the dynamics of the disease spread.

  12. Overlapping community detection in complex networks using symmetric binary matrix factorization.

    PubMed

    Zhang, Zhong-Yuan; Wang, Yong; Ahn, Yong-Yeol

    2013-06-01

    Discovering overlapping community structures is a crucial step to understanding the structure and dynamics of many networks. In this paper we develop a symmetric binary matrix factorization model to identify overlapping communities. Our model allows us not only to assign community memberships explicitly to nodes, but also to distinguish outliers from overlapping nodes. In addition, we propose a modified partition density to evaluate the quality of community structures. We use this to determine the most appropriate number of communities. We evaluate our methods using both synthetic benchmarks and real-world networks, demonstrating the effectiveness of our approach. PMID:23848725

  13. Remarks on the k-error linear complexity of -periodic sequences

    E-print Network

    Yanikoglu, Berrin

    Remarks on the k-error linear complexity of pn -periodic sequences Wilfried Meidl1 and Ayineedi -periodic binary sequences with given 1-error linear complexity, and an exact formula for the expected 1, of a random 2n -periodic binary sequence. A crucial role for the anal- ysis played the Chan-Games algorithm

  14. BiCMOS Implementation of a Full-digital Linearized System for Complex Modulation Transmitter

    E-print Network

    Boyer, Edmond

    BiCMOS Implementation of a Full-digital Linearized System for Complex Modulation Transmitter Jorge power, full-digital, linearized system for complex modulation transmitter. The circuit is devoted to all In the context of the proliferation of various standards in 3G or more, the evolution of transmitters leads

  15. An invitation to Linear Time How to fit Computational Complexity to

    E-print Network

    Edmundo, Mário Jorge

    that there is no universal notion of Linear Time and different versions of Linear Time are appropriate for different Time in a general (universal?) sense. . . with some implicit model: Random Access Machine (RAM), iAn invitation to Linear Time or How to fit Computational Complexity to Algorithm Analysis? Etienne

  16. A 2.5 mW 370 mV/pF high linearity stray-immune symmetrical readout circuit for capacitive sensors

    NASA Astrophysics Data System (ADS)

    Kaimin, Zhou; Ziqiang, Wang; Chun, Zhang; Zhihua, Wang

    2012-06-01

    A stray-insensitive symmetrical capacitance-to-voltage converter for capacitive sensors is presented. By introducing a reference branch, a symmetrical readout circuit is realized. The linear input range is increased, and the systematic offsets of two input op-amps are cancelled. The common-mode noise and even-order distortion are also rejected. A chopper stabilization technique is adopted to further reduce the offset and flicker noise of the op-amps, and a Verilog-A-based varactor is used to model the real variable sensing capacitor. Simulation results show that the output voltage of this proposed readout circuit responds correctly, while the under-test capacitance changes with a frequency of 1 kHz. A metal-insulator-metal capacitor array is designed on chip for measurement, and the measurement results show that this circuit achieves sensitivity of 370 mV/pF, linearity error below 1% and power consumption as low as 2.5 mW. This symmetrical readout circuit can respond to an FPGA controlled sensing capacitor array changed every 1 ms.

  17. Critical coupling and coherent perfect absorption for ranges of energies due to a complex gain and loss symmetric system

    SciTech Connect

    Hasan, Mohammad, E-mail: mohammadhasan786@gmail.com [ISRO Satellite Centre (ISAC), Bangalore-560017 (India); Ghatak, Ananya, E-mail: gananya04@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Mandal, Bhabani Prasad, E-mail: bhabani.mandal@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India)

    2014-05-15

    We consider a non-Hermitian medium with a gain and loss symmetric, exponentially damped potential distribution to demonstrate different scattering features analytically. The condition for critical coupling (CC) for unidirectional wave and coherent perfect absorption (CPA) for bidirectional waves are obtained analytically for this system. The energy points at which total absorption occurs are shown to be the spectral singular points for the time reversed system. The possible energies at which CC occurs for left and right incidence are different. We further obtain periodic intervals with increasing periodicity of energy for CC and CPA to occur in this system. -- Highlights: •Energy ranges for CC and CPA are obtained explicitly for complex WS potential. •Analytical conditions for CC and CPA for PT symmetric WS potential are obtained. •Conditions for left and right CC are shown to be different. •Conditions for CC and CPA are shown to be that of SS for the time reversed system. •Our model shows the great flexibility of frequencies for CC and CPA.

  18. On the solutions of some linear complex quaternionic equations.

    PubMed

    Bolat, Cennet; ?pek, Ahmet

    2014-01-01

    Some complex quaternionic equations in the type AX - XB = C are investigated. For convenience, these equations were called generalized Sylvester-quaternion equations, which include the Sylvester equation as special cases. By the real matrix representations of complex quaternions, the necessary and sufficient conditions for the solvability and the general expressions of the solutions are obtained. PMID:25101318

  19. On the Solutions of Some Linear Complex Quaternionic Equations

    PubMed Central

    ?pek, Ahmet

    2014-01-01

    Some complex quaternionic equations in the type AX ? XB = C are investigated. For convenience, these equations were called generalized Sylvester-quaternion equations, which include the Sylvester equation as special cases. By the real matrix representations of complex quaternions, the necessary and sufficient conditions for the solvability and the general expressions of the solutions are obtained. PMID:25101318

  20. Development of virus-like particle technology from small highly symmetric to large complex virus-like particle structures.

    PubMed

    Pushko, Peter; Pumpens, Paul; Grens, Elmars

    2013-01-01

    Virus-like particle (VLP) technology is a promising approach for the construction of novel vaccines, diagnostic tools, and gene therapy vectors. Initially, VLPs were primarily derived from non-enveloped icosahedral or helical viruses and proved to be viable vaccine candidates due to their effective presentation of epitopes in a native conformation. VLP technology has also been used to prepare chimeric VLPs decorated with genetically fused or chemically coupled epitope stretches selected from immunologically defined target proteins. However, structural constraints associated with the rigid geometrical architecture of icosahedral or helical VLPs pose challenges for the expression and presentation of large epitopes. Complex VLPs derived from non-symmetric enveloped viruses are increasingly being used to incorporate large epitopes and even full-length foreign proteins. Pleomorphic VLPs derived from influenza or other enveloped viruses can accommodate multiple full-length and/or chimeric proteins that can be rationally designed for multifunctional purposes, including multivalent vaccines. Therefore, a second generation of VLP carriers is represented by complex particles reconstructed from natural or chimeric structural proteins derived from complex enveloped viruses. Further development of safe and efficient VLP nanotechnology may require a rational combination of both approaches. PMID:23594863

  1. Condensation phase transitions of symmetric conserved-mass aggregation model on complex networks

    NASA Astrophysics Data System (ADS)

    Kwon, Sungchul; Lee, Sungmin; Kim, Yup

    2006-05-01

    We investigate condensation phase transitions of the symmetric conserved-mass aggregation (SCA) model on random networks (RNs) and scale-free networks (SFNs) with degree distribution P(k)˜k-? . In the SCA model, masses diffuse with unit rate, and unit mass chips off from mass with rate ? . The dynamics conserves total mass density ? . In the steady state, on RNs and SFNs with ?>3 for ??? , we numerically show that the SCA model undergoes the same type of condensation transitions as those on regular lattices. However, the critical line ?c(?) depends on network structures. On SFNs with ??3 , the fluid phase of exponential mass distribution completely disappears and no phase transitions occurs. Instead, the condensation with exponentially decaying background mass distribution always takes place for any nonzero density. For the existence of the condensed phase for ??3 at the zero density limit, we investigate one lamb-lion problem on RNs and SFNs. We numerically show that a lamb survives indefinitely with finite survival probability on RNs and SFNs with ?>3 , and dies out exponentially on SFNs with ??3 . The finite lifetime of a lamb on SFNs with ??3 ensures the existence of the condensation at the zero density limit on SFNs with ??3 , at which direct numerical simulations are practically impossible. At ?=? , we numerically confirm that complete condensation takes place for any ?>0 on RNs. Together with the recent study on SFNs, the complete condensation always occurs on both RNs and SFNs in zero range process with constant hopping rate.

  2. The complex structure of Abell 2345: a galaxy cluster with non-symmetric radio relics

    E-print Network

    Boschin, Walter; Girardi, Marisa

    2010-01-01

    We aim to obtain new insights into the internal dynamics of the cluster Abell 2345. This cluster exhibits two non-symmetric radio relics well studied through recent, deep radio data. Our analysis is based on redshift data for 125 galaxies acquired at the Telescopio Nazionale Galileo and on new photometric data acquired at the Isaac Newton Telescope. We also use ROSAT/HRI archival X-ray data. We combine galaxy velocities and positions to select 98 cluster galaxies and analyze the internal dynamics of the cluster. We estimate a mean redshift =0.1789 and a LOS velocity dispersion \\sigma ~ 1070 km/s. The two-dimensional galaxy distribution reveals the presence of three significant peaks within a region of ~ 1 Mpc (the E, NW, and SW peaks). The spectroscopic catalog confirms the presence of these three clumps. The total mass of the cluster is very uncertain: M~ 2 10^15 solar masses. The E clump well coincides with the main mass peak as recovered from the weak gravitational lensing analysis and is off-set to the ea...

  3. C{sub 2}-symmetric Copper(II) complexes as chiral Lewis acids

    SciTech Connect

    Evans, D.A.; Murry, J.A.; Matt, P. von [Harvard Univ., Cambridge, MA (United States)] [and others

    1995-12-01

    Two new Cu(II)-derived Lewis acid catalysts 1 and 2 have been prepared and their utility as catalysts in the Diels-Alder reaction documented. While complex 1 is effective in catalyzing the cycloaddition of unsaturated aldehyde dienophiles with cyclopentadiene complex 2 is optimal for imide dienophiles. This study provides a rational basis for the design of Lewis acids based on the coordinating capacity of cationic Cu(II) complexes which possess sufficient Lewis acidity to catalyze a range of synthetically useful Diels-Alder reactions. In particular, documentation of the importance of counterion structure in the use of cationic metal centers as Lewis acids has been made for the first time.

  4. The linear and nonlinear rheology of multiscale complex fluids

    E-print Network

    Jaishankar, Aditya

    2014-01-01

    The microstructures of many complex fluids are typically characterized by a broad distribution of internal length scales. Examples of such multiscale materials include physically and chemically cross-linked gels, emulsions, ...

  5. Non-centro-symmetric electron diffraction pattern of icosahedral quasicrystal induced by combination of linear phason strain and curvature of Ewald sphere.

    PubMed

    Xiong, Dongxia; Lu, Lu; Wang, Jianbo; Zhao, Dongshan; Sun, Yufeng

    2013-01-01

    Non-centro-symmetric characteristics are observed in the experimental electron diffraction patterns (EDPs) from the icosahedral quasicrystalline precipitates in ZrAlNiCuNb alloys. Different from the well-known breaking of the Friedel's law, where a strong dynamical effect will reveal in EDPs the concealed non-centro-symmetry originated from the crystal structures themselves, the current results can be interpreted in terms of changes in deviation parameters due to a delicate combination of the linear phason strain characteristic of quasicrystals and the curvature of Ewald sphere. After taking this effect into consideration, the corresponding simulated EDPs fit quite well to the experimental data. PMID:24041584

  6. 1. 2-GeV damping-ring complex for the Stanford Linear Collider

    SciTech Connect

    Fischer, G.E.; Davies-White, W.; Fieguth, T.; Wiedemann, H.

    1983-07-01

    The choice of parameters, the design, a 2-1/2 year consruction program and the early operation of a high field, high tune research and development damping ring complex for one of the two linear collider beams are described.

  7. Complexity analysis of a linear complementarity algorithm based on a Lyapunov function

    Microsoft Academic Search

    Paul Tseng

    1992-01-01

    We consider a path following algorithm for solving linear complementarity problems with positive semi-definite matrices. This algorithm can start from any interior solution and attain a linear rate of convergence. Moreover, if the starting solution is appropriately chosen, this algorithm achieves a complexity of O(\\u000a

  8. Complex Plane and Parameter Plane Linear System Design Methods

    Microsoft Academic Search

    J. B. MOORE

    Summary Constraint equations and inequalities relating the adjustable parameters of a system are considered for a multi-parameter design. Constraints determined from the characteristic equation root specifications, dominant root parameter sensitivity specifications and error constant specifications are incorporated into the design analytically, while relative stability and dominancy constraints are considered using graphical methods on the parameter and complex planes.

  9. Solving the GPS Problem in Almost Linear Complexity

    E-print Network

    Glasner, Yair

    : A client on the earth surface wants to know his/her geographical location. The Global Positioning System[n]; (0.1) where 0 2 C is the complex amplitude, with j 0j 1; !0 2 ZN encodes the radial velocity lecture I will explain our recent group representation construction of sequences S that allow us

  10. Linear and nonlinear rheology of architecturally complex polymers

    NASA Astrophysics Data System (ADS)

    Kapnistos, Michail

    We investigated the linear and nonlinear rheology of several model polymeric materials ranging from combs with linear or star-like backbone to third generation dendrimers and cyclic polymers (with no free ends or branches). These systems are governed by topological interactions, which influence their mechanical properties. We combined experiments with theoretical models in order to identify the factors that affect the mechanical response of polymers of various architectures. All polymeric materials exhibited some universal features that were assigned to their microscopic motions. The tube model and the concept of hierarchy of motions along with the dynamic tube dilation (DTD) were the key elements to understand the rheology of branched polymer melts and solutions. We also performed nonlinear experiments in solutions of branched polymers obtaining an extensive dataset of damping functions in combs. We found evidence that the above ideas and mainly DTD, are also present during nonlinear deformations. Apart for the experiments, we modified the existent tube model, improving several shortcomings. The topological free ends of combs were treated simultaneously with the branches and included the effect of polydispersity in a direct manner. The equations were integrated with a user-friendly computer interface for modeling the linear viscoelastic data of several polymer architectures. We explored the role of polymer topology in rheology with the use of model polymers. We found universal principles that govern the mechanical response and linked the microstructure with macroscopic experiments. The extended experimental data have revealed some issues not explained by current theoretical model that need to be addressed in the future.

  11. Linear Conversion of Dust-Lattice Modes in Complex Plasmas

    SciTech Connect

    Yaroshenko, V.V.; Ivlev, A.V.; Morfill, G.E. [Max-Planck-Institut fuer Extraterrestrishe Physik, D-85741, Garching (Germany)

    2005-10-31

    The linear coupling between transverse and longitudinal dus-lattice modes due to anisotropy in dust-dust interactions is considered. A character of DL mode interactions is determined by a sign of the coupling coefficient. When this term is negative, the DL waves remain stable, but demonstrate a specific mode conversion. In the opposite case of positive coupling coefficient, the dust-lattice waves can be subjected to a resonance instability, the criterion for which has been derived. This instability can explain experimentally observed spontaneous excitation of vibrational modes in a plasma crystal when the pressure is decreased below a critical value.

  12. Coherent H? control for a class of linear complex quantum systems

    Microsoft Academic Search

    Aline I. Maalouf; Ian R. Petersen

    2009-01-01

    This paper considers a coherent Hinfin control problem for a class of linear quantum systems which can be defined by complex quantum stochastic differential equations in terms of annihilation operators only. For this class of quantum systems, a solution to the Hinfin control problem can be obtained in terms of a pair of complex Riccati equations. The paper also considers

  13. Complex transition metal hydrides: linear correlation of countercation electronegativity versus T-D bond lengths.

    PubMed

    Humphries, T D; Sheppard, D A; Buckley, C E

    2015-06-30

    For homoleptic 18-electron complex hydrides, an inverse linear correlation has been established between the T-deuterium bond length (T = Fe, Co, Ni) and the average electronegativity of the metal countercations. This relationship can be further employed towards aiding structural solutions and predicting physical properties of novel complex transition metal hydrides. PMID:26077621

  14. Linear complex polarization propagator in a four-component Kohn-Sham framework

    Microsoft Academic Search

    Sebastien Villaume; Trond Saue; Patrick Norman

    2010-01-01

    An algorithm for the solution of the linear response equation in the random phase approximation is presented. All entities including frequency arguments, matrices, and vectors, are assumed to be complex, and it represents the core equation solver needed in complex polarization propagator approaches where nonstimulated relaxation channels are taken into account. Stability and robustness of the algorithm are demonstrated in

  15. High resolution analysis of the complex symmetric CF3 stretching chromophore absorption in CF3I

    NASA Astrophysics Data System (ADS)

    He, Yabai; Hollenstein, Hans; Quack, Martin; Richard, Erik; Snels, Marcel; Bürger, Hans

    2002-01-01

    We report a detailed high resolution rovibrational analysis of the ?1 fundamental absorption band system of CF3I, which appears as a very complex resonance polyad. Pulsed slit jet diode laser spectra (instrumental bandwidth ?25 MHz) of CF3I (neat and seeded in He) at rotational temperatures of about 7, 30, and 70 K have been obtained. The low J, K part of the observed transitions can be fitted by a model including the anharmonically coupled levels ?1(?˜0=1076.0551 cm-1), 2?50(?˜0=1079.6732 cm-1) and ?3+3?6±3(?˜0=1072.3884 cm-1), and the local Coriolis perturber ?3+3?6+1(?˜0=1074.1845 cm-1). The level ?3+3?6+3 was observed and included for the first time, and an additional anharmonic coupling between the levels ?3+3?6+3 and ?3+3?6-3 proved relevant. In order to analyze the higher J, K regions, perturbations arising from 2?5±2 turned out to be important. In certain regions of the spectra, effects due to nuclear quadrupole interaction are clearly visible. We report new sets of parameters for a low J, K model and for an extended model including the perturber 2?5±2. The results are discussed in relation to infrared multiphoton excitation of CF3I, infrared absorption in the atmospheric window and intramolecular vibrational redistribution.

  16. Complex Craniofacial Changes in Blind Cave-Dwelling Fish Are Mediated by Genetically Symmetric and Asymmetric Loci

    PubMed Central

    Gross, Joshua B.; Krutzler, Amanda J.; Carlson, Brian M.

    2014-01-01

    The genetic regulators of regressive craniofacial morphologies are poorly understood. To shed light on this problem, we examined the freshwater fish Astyanax mexicanus, a species with surface-dwelling and multiple independent eyeless cave-dwelling forms. Changes affecting the skull in cavefish include morphological alterations to the intramembranous circumorbital bones encircling the eye. Many of these modifications, however, have evolved separately from eye loss, such as fragmentation of the third suborbital bone. To understand the genetic architecture of these eye-independent craniofacial alterations, we developed and scored 33 phenotypes in the context of an F2 hybrid mapping pedigree bred from Pachón cavefish and surface fish. We discovered several individuals exhibiting dramatic left–right differences in bone formation, such as extensive fragmentation on the right side only. This observation, along with well-known eye size asymmetry in natural cave-dwelling animals, led us to further evaluate left–right genetic differences for the craniofacial complex. We discovered three phenotypes, inclusive of bone fragmentation and fusion, which demonstrated a directional heritable basis only on one side. Interestingly, the overall areas of affected bones were genetically symmetric. Phenotypic effect plots of these novel craniofacial QTL revealed that cave alleles are associated with abnormal conditions such as bony fusion and fragmentation. Moreover, many linked loci overlapped with other cave-associated traits, suggesting regressive craniofacial changes may evolve through linkage or as antagonistic pleiotropic consequences of cave-associated adaptations. These novel findings illuminate significant craniofacial changes accompanying evolution in complete darkness and reveal complex changes to the skull differentially influenced by genetic changes affecting the left and right sides. PMID:24496009

  17. Low-complexity lossless compression of hyperspectral imagery via linear prediction

    Microsoft Academic Search

    Francesco Rizzo; Bruno Carpentieri; Giovanni Motta; James A. Storer

    2005-01-01

    We present a new low-complexity algorithm for hyperspectral image compression that uses linear prediction in the spectral domain. We introduce a simple heuristic to estimate the performance of the linear predictor from a pixel spatial context and a context modeling mechanism with one-band look-ahead capability, which improves the overall compression with marginal usage of additional memory. The proposed method is

  18. Some comparisons of complexity in dictionary-based and linear computational models.

    PubMed

    Gnecco, Giorgio; K?rková, V?ra; Sanguineti, Marcello

    2011-03-01

    Neural networks provide a more flexible approximation of functions than traditional linear regression. In the latter, one can only adjust the coefficients in linear combinations of fixed sets of functions, such as orthogonal polynomials or Hermite functions, while for neural networks, one may also adjust the parameters of the functions which are being combined. However, some useful properties of linear approximators (such as uniqueness, homogeneity, and continuity of best approximation operators) are not satisfied by neural networks. Moreover, optimization of parameters in neural networks becomes more difficult than in linear regression. Experimental results suggest that these drawbacks of neural networks are offset by substantially lower model complexity, allowing accuracy of approximation even in high-dimensional cases. We give some theoretical results comparing requirements on model complexity for two types of approximators, the traditional linear ones and so called variable-basis types, which include neural networks, radial, and kernel models. We compare upper bounds on worst-case errors in variable-basis approximation with lower bounds on such errors for any linear approximator. Using methods from nonlinear approximation and integral representations tailored to computational units, we describe some cases where neural networks outperform any linear approximator. PMID:21094023

  19. Non-linear dynamic complexity of the human EEG during meditation.

    PubMed

    Aftanas, L I; Golocheikine, S A

    2002-09-20

    We used non-linear analysis to investigate the dynamical properties underlying the EEG in the model of Sahaja Yoga meditation. Non-linear dimensional complexity (DCx) estimates, indicating complexity of neuronal computations, were analyzed in 20 experienced meditators during rest and meditation using 62-channel EEG. When compared to rest, the meditation was accompanied by a focused decrease of DCx estimates over midline frontal and central regions. By contrast, additionally computed linear measures exhibited the opposite direction of changes: power in the theta-1 (4-6 Hz), theta-2 (6-8 Hz) and alpha-1 (8-10 Hz) frequency bands was increased over these regions. The DCx estimates negatively correlated with theta-2 and alpha-1 and positively with beta-3 (22-30 Hz) band power. It is suggested that meditative experience, characterized by less complex dynamics of the EEG, involves 'switching off' irrelevant networks for the maintenance of focused internalized attention and inhibition of inappropriate information. Overall, the results point to the idea that dynamically changing inner experience during meditation is better indexed by a combination of non-linear and linear EEG variables. PMID:12231432

  20. Linear Complexity over Fp of M-ary Sidel'nikov Sequences 1

    E-print Network

    No, Jong-Seon

    -Seon No, and **Habong Chung *School of Electrical Engineering and Computer Science, Seoul National discrete Fourier transform. As an example, we represent the linear complexities of the ternary Sidel in the analysis of the sequence. For a positive integer m such that M|pm - 1, Sidel'nikov [8] constructed M

  1. Linearly Compressed Pages: A Main Memory Compression Framework with Low Complexity and Low Latency

    E-print Network

    Linearly Compressed Pages: A Main Memory Compression Framework with Low Complexity and Low Latency@cmu.edu Categories and Subject Descriptors: B.3.2 [Design Styles]: Primary Memory, Cache Memories Keywords: Main memory compression, cache compression 1. Introduction and Motivation Main memory is a critical resource

  2. Local Genealogies in a Linear Mixed Model for Genome-Wide Association Mapping in Complex

    E-print Network

    Schierup, Mikkel Heide

    Local Genealogies in a Linear Mixed Model for Genome-Wide Association Mapping in Complex Pedigreed fashion. Here, we present a complementary approach, called `GENMIX (genealogy based mixed model)' which combines advantages from two powerful GWAS methods: genealogy-based haplotype grouping and MMA. Subjects

  3. Main Vector Adaptation: A CMA Variant with Linear Time and Space Complexity

    E-print Network

    Zell, Andreas

    Main Vector Adaptation: A CMA Variant with Linear Time and Space Complexity Jan Poland University T The covariance matrix adaptation (CMA) is one of the most powerful self adapta- tion mechanisms for Evolution Strategies. However, for increasing search space dimen- sion N, the performance declines, since the CMA has

  4. Learning Probabilistic Non-Linear Models for Tracking Complex Activities: Extended

    E-print Network

    Gall, Juergen

    Learning Probabilistic Non-Linear Models for Tracking Complex Activities: Extended Experimentation tracking on the CMU dataset. 1 Neighborhood type and size We tested three different distance measures ('xL2' - Euclidean distance in the latent space, 'yL2' - Euclidean distance in the data space and 'temp' - temporal

  5. SOME OSCILLATION RESULTS FOR LINEAR DIFFERENTIAL EQUATIONS IN THE COMPLEX PLANE

    E-print Network

    Chiang, Edmund Yik-Man

    SOME OSCILLATION RESULTS FOR LINEAR DIFFERENTIAL EQUATIONS IN THE COMPLEX PLANE Yik-Man Chiang.7). 1991 Mathematics Subject Classification. 1991 Primary 34A20, 30D35; Secondary 34C10. Key words obtained by Y. Chiang in his London thesis [7], partially improved by Y. Chiang [8]. The aim

  6. Complex representations of the full linear group over a finite field

    Microsoft Academic Search

    D. K. Faddeev

    1978-01-01

    The properties of the system of irreducible complex representations of full linear groups are described, without making use of the characteristics of the representations. The description is given in terms involving the multiplication of irreducible representations, which was introduced by Green. Explicitly, the concept of prime and primary representations is introduced, theorems are proved on the unique decomposition into primary

  7. PT-symmetric strings

    SciTech Connect

    Amore, Paolo, E-mail: paolo.amore@gmail.com [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico); Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Garcia, Javier [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Gutierrez, German [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico)

    2014-04-15

    We study both analytically and numerically the spectrum of inhomogeneous strings with PT-symmetric density. We discuss an exactly solvable model of PT-symmetric string which is isospectral to the uniform string; for more general strings, we calculate exactly the sum rules Z(p)??{sub n=1}{sup ?}1/E{sub n}{sup p}, with p=1,2,… and find explicit expressions which can be used to obtain bounds on the lowest eigenvalue. A detailed numerical calculation is carried out for two non-solvable models depending on a parameter, obtaining precise estimates of the critical values where pair of real eigenvalues become complex. -- Highlights: •PT-symmetric Hamiltonians exhibit real eigenvalues when PT symmetry is unbroken. •We study PT-symmetric strings with complex density. •They exhibit regions of unbroken PT symmetry. •We calculate the critical parameters at the boundaries of those regions. •There are exact real sum rules for some particular complex densities.

  8. On the Path-Integral Derivation of the Anomaly for the Hermitian Equivalent of the Complex $PT$-Symmetric Quartic Hamiltonian

    E-print Network

    Jones, H F; Rivers, R J

    2006-01-01

    It can be shown using operator techniques that the non-Hermitian $PT$-symmetric quantum mechanical Hamiltonian with a "wrong-sign" quartic potential $-gx^4$ is equivalent to a Hermitian Hamiltonian with a positive quartic potential together with a linear term. A naive derivation of the same result in the path-integral approach misses this linear term. In a recent paper by Bender et al. it was pointed out that this term was in the nature of a parity anomaly and a more careful, discretized treatment of the path integral appeared to reproduce it successfully. However, on re-examination of this derivation we find that a yet more careful treatment is necessary, keeping terms that were ignored in that paper. An alternative, much simpler derivation is given using the additional potential that has been shown to appear whenever a change of variables to curvilinear coordinates is made in a functional integral.

  9. A self-consistent three-wave coupling model with complex linear frequencies

    SciTech Connect

    Kim, J.-H.; Terry, P. W. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2011-09-15

    A three-wave coupling model with complex linear frequencies is investigated for the nonlinear interaction in a triad that has linearly unstable and stable modes. Time scales associated with linear and nonlinear physics are identified and compared with features of the frequency spectrum. From appropriate time scales, the frequency spectra are well characterized even in the transition to the steady state. The nonlinear time scales that best match spectral features are the nonlinear frequency of the fixed point and a frequency that depends on the amplitude displacement from the fixed point through the large-amplitude Jacobian elliptic solution. Two limited efforts to model the effect of other triads suggest robustness in the single triad results.

  10. A Simple Modification in CMA-ES Achieving Linear Time and Space Complexity

    Microsoft Academic Search

    Raymond Ros; Nikolaus Hansen

    2008-01-01

    This paper proposes a simple modification of the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) for high dimensional objective func- tions, reducing the internal time and space complexity from quadratic to linear. The covariance matrix is constrained to be diagonal and the resulting algorithm, sep-CMA-ES, samples each coordinate independently. Because the model com- plexity is reduced, the learning rate for the

  11. Finding Lower Bounds on the Complexity of Secret Sharing Schemes by Linear Programming

    Microsoft Academic Search

    Carles Padró; Leonor Vázquez

    2010-01-01

    \\u000a Determining the optimal complexity of secret sharing schemes for every given access structure is a difficult and long-standing\\u000a open problem in cryptology. Lower bounds have been found by a combinatorial method that uses polymatroids. In this paper,\\u000a we point out that the best lower bound that can be obtained by this method can be determined by using linear programming,\\u000a and

  12. Synthesis, spectral characterization, DNA binding ability and antibacterial screening of copper(II) complexes of symmetrical NOON tetradentate Schiff bases bearing different bridges

    NASA Astrophysics Data System (ADS)

    Bahaffi, Saleh O.; Abdel Aziz, Ayman A.; El-Naggar, Maher M.

    2012-08-01

    A novel series of four copper(II) complexes were synthesized by thermal reaction of copper acetate salt with symmetrical tetradentate Schiff bases, N,N'bis(o-vanillin)4,5-dimethyl-l,2-phenylenediamine (H2L1), N,N'bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L2), N,N'bis(o-vanillin)4,5-dichloro-1,2-phenylenediamine (H2L3) and N,N'bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L4), respectively. All the new synthesized complexes were characterized by using of microanalysis, FT-IR, UV-Vis, magnetic measurements, ESR, and conductance measurements, respectively. The data revealed that all the Schiff bases (H2L1-4) coordinate in their deprotonated forms and behave as tetradentate NOON coordinated ligands. Moreover, their copper(II) complexes have square planar geometry with general formula [CuL1-4]. The binding of the complexes with calf thymus DNA (CT-DNA) was investigated by UV-Vis spectrophotometry, fluorescence quenching and viscosity measurements. The results indicated that the complexes bind to CT-DNA through an intercalative mode. From the biological activity view, the copper(II) complexes and their parent ligands were screened for their in vitro antibacterial activity against the bacterial species Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosai by well diffusion method. The complexes showed an increased activity in comparison to some standard drugs.

  13. The linear ubiquitin assembly complex (LUBAC) is essential for NLRP3 inflammasome activation

    PubMed Central

    Rodgers, Mary A.; Bowman, James W.; Fujita, Hiroaki; Orazio, Nicole; Shi, Mude; Liang, Qiming; Amatya, Rina; Kelly, Thomas J.; Iwai, Kazuhiro; Ting, Jenny

    2014-01-01

    Linear ubiquitination is a newly discovered posttranslational modification that is currently restricted to a small number of known protein substrates. The linear ubiquitination assembly complex (LUBAC), consisting of HOIL-1L, HOIP, and Sharpin, has been reported to activate NF-?B–mediated transcription in response to receptor signaling by ligating linear ubiquitin chains to Nemo and Rip1. Despite recent advances, the detailed roles of LUBAC in immune cells remain elusive. We demonstrate a novel HOIL-1L function as an essential regulator of the activation of the NLRP3/ASC inflammasome in primary bone marrow–derived macrophages (BMDMs) independently of NF-?B activation. Mechanistically, HOIL-1L is required for assembly of the NLRP3/ASC inflammasome and the linear ubiquitination of ASC, which we identify as a novel LUBAC substrate. Consequently, we find that HOIL-1L?/? mice have reduced IL-1? secretion in response to in vivo NLRP3 stimulation and survive lethal challenge with LPS. Together, these data demonstrate that linear ubiquitination is required for NLRP3 inflammasome activation, defining the molecular events of NLRP3 inflammasome activation and expanding the role of LUBAC as an innate immune regulator. Furthermore, our observation is clinically relevant because patients lacking HOIL-1L expression suffer from pyogenic bacterial immunodeficiency, providing a potential new therapeutic target for enhancing inflammation in immunodeficient patients. PMID:24958845

  14. Steric hindrances create a discrete linear Dy4 complex exhibiting SMM behaviour.

    PubMed

    Lin, Shuang-Yan; Zhao, Lang; Ke, Hongshan; Guo, Yun-Nan; Tang, Jinkui; Guo, Yang; Dou, Jianmin

    2012-03-21

    Two linear tetranuclear lanthanide complexes of general formula [Ln(4)(L)(2)(C(6)H(5)COO)(12)(MeOH)(4)], where HL = 2,6-bis((furan-2-ylmethylimino)methyl)-4-methylphenol, () and Ln(III) = Dy(III) (1) and Gd(III) (2), have been synthesized and characterized. The crystal structural analysis demonstrates that two Schiff-base ligands inhibit the growth of benzoate bridged 1D chains, leading to the isolation of discrete tetranuclear complexes due to their steric hindrances. Every Ln(III) ion is coordinated by eight donor atoms in a distorted bicapped trigonal-prismatic arrangement. Alternating current (ac) susceptibility measurements of complex 1 reveal a frequency- and temperature-dependent out-of-phase signal under zero dc field, typical of single-molecule magnet (SMM) behaviour with an anisotropic barrier ?(eff) = 17.2 K. PMID:22286075

  15. Linear complexity integral-equation based methods for large-scale electromagnetic analysis

    NASA Astrophysics Data System (ADS)

    Chai, Wenwen

    In general, to solve problems with N parameters, the optimal computational complexity is linear complexity O( N). However, for most computational electromagnetic methods, the complexity is higher than O(N). In this work, we introduced and further developed the H - and H2 -matrix based mathematical framework to break the computational barrier of existing integral-equation (IE)-based methods for large-scale electromagnetic analysis. Our significant contributions include the first-time dense matrix inversion and LU factorization of O(N) complexity for large-scale 3-D circuit extraction and a fast direct integral equation solver that outperforms existing direct solvers for large-scale electrodynamic analysis having millions of unknowns and ˜100 wavelengths. The major contributions of this work are: (1) Direct Matrix Solution of Linear Complexity for 3-D Integrated Circuit (IC) and Package Extraction • O(N) complexity dense matrix inversion and LU factorization algorithms and their applications to capacitance extraction and impedance extraction of large-scale 3-D circuits • O(N) direct matrix solution of highly irregular matrices consisting of both dense and sparse matrix blocks arising from full-wave analysis of general 3-D circuits with lossy conductors in multiple dielectrics. (2) Fast H - and H2 -Based IE Solvers for Large-Scale Electrodynamic Analysis • theoretical proof on the error bounded low-rank representation of electrodynamic integral operators • fast H2 -based iterative solver with O(N) computational cost and controlled accuracy from small to tens of wavelengths • fast H -based direct solver with computational cost minimized based on accuracy • Findings on how to reduce the complexity of H - and H2 -based methods for electrodynamic analysis, which are also applicable to many other fast IE solvers. (3) Fast Algorithms for Accelerating H - and H2 -Based Iterative and Direct Solvers • Optimal H -based representation and its applications from circuits to electrically large problems • Optimal H2 -based representation for dense matrices arising from IE-based analysis • Iterative as well as direct solvers significantly accelerated by optimal H - and H2 -based representations. (4) Advanced Mathematical Computing • The construction of a simple H2 -representation with Csp = 1 • Linear-time matrix-matrix multiplication with controlled accuracy. The proposed methods have successfully solved large-scale electromagnetic scattering problems having 100 wavelengths and integrated circuit problems involving millions of unknowns in fast CPU time, modest memory consumption, and without sacrificing accuracy. Comparisons with state-of-the-art solvers have demonstrated the clear advantages of the proposed methods. The proposed methods have important applications in a wide range of areas such as electromagnetics, optics, acoustics, plasmonics, etc.

  16. Critical coupling and coherent perfect absorption for ranges of energies due to a complex gain and loss symmetric system

    E-print Network

    Mohammad Hasan; Ananya Ghatak; Bhabani Prasad Mandal

    2014-03-03

    We consider a non-Hermitian medium with a gain and loss symmetric, exponentially damped potential distribution to demonstrate different scattering features analytically. The condition for critical coupling (CC) for unidirectional wave and coherent perfect absorption (CPA) for bidirectional waves are obtained analytically for this system. The energy points at which total absorption occurs are shown to be the spectral singular points for the time reversed system. The possible energies at which CC occurs for left and right incidence are different. We further obtain periodic intervals with increasing periodicity of energy for CC and CPA to occur in this system.

  17. A non-canonical UBA–UBL interaction forms the linear-ubiquitin-chain assembly complex

    PubMed Central

    Yagi, Hirokazu; Ishimoto, Kazuhiro; Hiromoto, Takeshi; Fujita, Hiroaki; Mizushima, Tsunehiro; Uekusa, Yoshinori; Yagi-Utsumi, Maho; Kurimoto, Eiji; Noda, Masanori; Uchiyama, Susumu; Tokunaga, Fuminori; Iwai, Kazuhiro; Kato, Koichi

    2012-01-01

    HOIL-1L and its binding partner HOIP are essential components of the E3-ligase complex that generates linear ubiquitin (Ub) chains, which are critical regulators of NF-?B activation. Using crystallographic and mutational approaches, we characterize the unexpected structural basis for the specific interaction between the Ub-like domain (UBL) of HOIL-1L and the Ub-associated domain (UBA) of HOIP. Our data indicate the functional significance of this non-canonical mode of UBA–UBL interaction in E3 complex formation and subsequent NF-?B activation. This study highlights the versatility and specificity of protein–protein interactions involving Ub/UBLs and their cognate proteins. PMID:22430200

  18. Essential Role of the Linear Ubiquitin Chain Assembly Complex in Lymphoma Revealed by Rare Germline Polymorphisms

    PubMed Central

    Yang, Yibin; Schmitz, Roland; Mitala, Joseph; Whiting, Amanda; Xiao, Wenming; Ceribelli, Michele; Wright, George W.; Zhao, Hong; Yang, Yandan; Xu, Weihong; Rosenwald, Andreas; Ott, German; Gascoyne, Randy D.; Connors, Joseph M.; Rimsza, Lisa M.; Campo, Elias; Jaffe, Elaine S.; Delabie, Jan; Smeland, Erlend B.; Braziel, Rita M.; Tubbs, Raymond R.; Cook, James. R.; Weisenburger, Dennis D.; Chan, Wing C.; Wiestner, Adrian; Kruhlak, Michael J.; Iwai, Kazuhiro; Bernal, Federico; Staudt, Louis M.

    2014-01-01

    Constitutive activation of NF-?B is a hallmark of the activated B cell-like (ABC) subtype of diffuse large B cell lymphoma (DLBCL), owing to upstream signals from the B cell receptor (BCR) and MyD88 pathways. The linear polyubiquitin chain assembly complex (LUBAC) attaches linear polyubiquitin chains to I?B kinase ?, a necessary event in some pathways that engage NF-?B. Two germ line polymorphisms affecting the LUBAC subunit RNF31 are rare among healthy individuals (~1%) but enriched in ABC DLBCL (7.8%). These polymorphisms alter RNF31 ? helices that mediate binding to the LUBAC subunit RBCK1, thereby increasing RNF31-RBCK1 association, LUBAC enzymatic activity, and NF-?B engagement. In the BCR pathway, LUBAC associates with the CARD11/MALT1/BCL10 adapter complex and is required for ABC DLBCL viability. A stapled RNF31 ?-helical peptide based on the ABC DLBCL-associated Q622L polymorphism inhibited RFN31-RBCK1 binding, decreased NF-?B and killed ABC DLBCL cells, credentialing this protein-protein interface as a therapeutic target. PMID:24491438

  19. Palladium(II) and platinum(II) complexes of a symmetric Schiff base derived from 2,6,diformyl-4-methylphenol with N-aminopyrimidine: Synthesis, characterization and detection of DNA interaction by voltammetry

    Microsoft Academic Search

    Mehmet Sönmez; Metin Çelebi; Yavuz Yard?m; Zühre ?entürk

    2010-01-01

    The two new mononuclear complexes were prepared by reacting symmetric Schiff base, containing pyrimidine rings and the metal chlorides of Pd(II) and Pt(II) in methanol. The mononuclear structure of the complexes was confirmed on the basis of elemental analyses, magnetic susceptibility, IR, UV–Vis, NMR, DTA\\/TGA and API-ES mass spectral data. The interaction of these metal complexes with fish sperm double-stranded

  20. Linear assembly of a porphyrin-C60 complex confined in vertical nanocylinders of amphiphilic block copolymer films.

    PubMed

    Kamimura, Takuya; Komura, Motonori; Komiyama, Hideaki; Iyoda, Tomokazu; Tani, Fumito

    2015-01-31

    Linear assemblies of a 1?:?1 porphyrin-fullerene C60 complex were formed in vertical cylindrical polyether nanodomains of amphiphilic block copolymer films by a simple spin coating-annealing method. The nanocylinder structures were retained even with high contents of the complex in the polymer films. PMID:25512950

  1. The Floquet Method for $PT$-symmetric Periodic Potentials

    E-print Network

    H. F. Jones

    2012-11-07

    By the general theory of $PT$-symmetric quantum systems, their energy levels are either real or occur in complex-conjugate pairs, which implies that the secular equation must be real. However, for periodic potentials it is by no means clear that the secular equation arising in the Floquet method is indeed real, since it involves two linearly independent solutions of the Schr\\"odinger equation. In this brief note we elucidate how that reality can be established.

  2. Preparation, linear and NLO properties of DNA-CTMA-SBE complexes

    NASA Astrophysics Data System (ADS)

    Manea, Ana-Maria; Rau, Ileana; Kajzar, Francois; Meghea, Aurelia

    2013-10-01

    Synthesis of deoxyribonucleic acid (DNA) - was cetyltrimethylammonium (CTMA) - sea buckthorn extract (SBE) at different concentrations is decribed. The complexes were processed into good optical quality thin films by spin coating on different substrates such as: glass, silica and ITO covered glass substrates. SBE contains many bioactive substances that can be used in the treatment of several diseases, such as cardiovascular disease, cancer, and acute mountain sickness. The obtained thin films were characterized for their spectroscopic, fluorescent, linear and nonlinear optical properties as function of SBE concentration. The third-order nonlinear optical (NLO) properties of thin films were determined by the optical third-harmonic generation technique at 1 064.2 nm fundamental wavelength.

  3. Synthesis and characterization of a series of transition metal complexes with a new symmetrical polyoxaaza macroacyclic Schiff base ligand: X-ray crystal structure of cobalt(II) and nickel(II) complexes and their antibacterial properties.

    PubMed

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Valencia, Laura

    2013-01-15

    A new symmetrical [N4O2] hexadentate Schiff base ligand, (E)-N-(pyridin-2-ylmethylene)-2-(3-(2-((E)-pyridin-2-lmethyleneamino)phenoxy)naphthalen-2-yloxy)benzenamine, abbreviated to L, and its complexes of Ni(II), Cu(II), Zn(II), Co(II), Cd(II) and Mn(II) have been synthesized in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV-Vis, NMR and molar conductivity. The crystal structures of two complexes, [NiL(ONO2)2]·2H2O and [CoLCl2]CH3OH·0.5H2O, have been determined by a single crystal X-ray diffraction study. In these complexes, the ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms. The metal ions complete their six coordination with two coordinated nitrate or chloride ions, forming a distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epid and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The activity data show that the complexes are more potent antibacterials than the parent Schiff base. PMID:23099161

  4. Complex non-linear modal analysis for mechanical systems: Application to turbomachinery bladings with friction interfaces

    NASA Astrophysics Data System (ADS)

    Laxalde, Denis; Thouverez, Fabrice

    2009-05-01

    A method for modal analysis of non-linear and non-conservative mechanical systems is proposed. In particular, dry-friction nonlinearities are considered although the method is not restricted to these. Based on the concept of complex nonlinear modes, eigensolutions are written as generalized Fourier series and the eigenproblem is then formulated in the frequency-domain. An alternating frequency-time domain method is used for the calculation of implicit nonlinear forces. A two degrees-of-freedom example featuring dry-friction illustrates the method and highlights the effects of dissipation on modal parameters. The stabilizing effects of friction in presence of negative damping in the system are also addressed. Then an application on a large-scale nonlinear system consisting of a turbomachinery blade, with dry-friction interfaces is proposed. In the latter, an original framework for the description of two-dimensional frictional motions by complex variables is proposed and applied, in particular, to a Dahl model. Effects of friction parameters and models on the blade's modal characteristics are investigated.

  5. A new ion mobility-linear ion trap instrument for complex mixture analysis.

    PubMed

    Donohoe, Gregory C; Maleki, Hossein; Arndt, James R; Khakinejad, Mahdiar; Yi, Jinghai; McBride, Carroll; Nurkiewicz, Timothy R; Valentine, Stephen J

    2014-08-19

    A new instrument that couples a low-pressure drift tube with a linear ion trap mass spectrometer is demonstrated for complex mixture analysis. The combination of the low-pressure separation with the ion trapping capabilities provides several benefits for complex mixture analysis. These include high sensitivity, unique ion fragmentation capabilities, and high reproducibility. Even though the gas-phase separation and the mass measurement steps are each conducted in an ion filtering mode, detection limits for mobility-selected peptide ions are in the tens of attomole range. In addition to ion separation, the low-pressure drift tube can be used as an ion fragmentation cell yielding mobility-resolved fragment ions that can be subsequently analyzed by multistage tandem mass spectrometry (MS(n)) methods in the ion trap. Because of the ion trap configuration, these methods can be comprised of any number (limited by ion signal) of collision-induced dissociation (CID) and electron transfer dissociation (ETD) processes. The high reproducibility of the gas-phase separation allows for comparison of two-dimensional ion mobility spectrometry (IMS)-MS data sets in a pixel-by-pixel fashion without the need for data set alignment. These advantages are presented in model analyses representing mixtures encountered in proteomics and metabolomics experiments. PMID:25068446

  6. IEEE COMMUNICATIONS LETTERS 1 Symmetric and a-symmetric Slepian-Wolf codes

    E-print Network

    Dragotti, Pier Luigi

    IEEE COMMUNICATIONS LETTERS 1 Symmetric and a-symmetric Slepian-Wolf codes with systematic and non channel codes that can achieve any point of the Slepian-Wolf achievable rate region. Our approach is very coding, Slepian-Wolf theo- rem, symmetric encoding, linear channel codes. I. INTRODUCTION THE Slepian-Wolf

  7. Axially Symmetric Black Hole Skyrmions

    E-print Network

    Sawado, N; Sawado, Nobuyuki; Shiiki, Noriko

    2003-01-01

    It has been known that a B=2 skyrmion is axially symmetric. We consider the Skyrme model coupled to gravity and obtain static axially symmetric black hole solutions numerically. The black hole skyrmion no longer has integer baryonic charge but has fractional charge outside the horizon as in the spherically symmetric case. Therefore, the solution represents a black hole partially swallowing a deuteron. Recent studies of theories with large extra dimensions suggest an effective Planck scale of order a TeV and thus the deuteron black hole may be produced in the Linear Hadron Collider (LHC) in future.

  8. Spin depolarizing effect in collisions with neutral hydrogen. II. Application to simple/complex ions in spherically symmetric states

    NASA Astrophysics Data System (ADS)

    Derouich, M.; Barklem, P. S.

    2007-02-01

    Aims: We develop an accurate and general semi-classical formalism that deals with the definition and the calculation of the collisional depolarizing constants of the levels of simple and complex singly-ionized atoms in arbitrary s-states perturbed by collisions with hydrogen atoms. The case of ions with hyperfine structure is investigated fully. Methods: We obtain potential energy curves based on the MSMA exchange perturbation theory by employing the Unsöld approximation. These potentials enter the Schrödinger equation to determine the collisional T-matrix elements in a semi-classical description. We use the T-matrix elements for the calculation of the collisional depolarization rates of simple atoms. Then, we use these rates to calculate the collisional coefficients in cases of ions with hyperfine structure. Results: We evaluate the collisional depolarization and polarization transfer rates of the ground levels of the ionized alkaline earth metals Be II, Mg II, Ca II, Sr II, and Ba II. We study the variation of the collisional rates with effective principal quantum number n* characterizing an arbitrary s-state of a perturbed simple ion. We find that the collisional rates for simple ions obey simple power laws as a function of n^*. We present direct and indirect formulations of the problem of the calculation of the depolarization and polarization transfer rates of levels of complex atoms and hyperfine levels from those for simple atoms. In particular, the indirect method allows a quick and simple calculation with its simple power-law relations. For the state 4s ^2S{1/2} of Ca II, our computed rate of the destruction of orientation differs from existing quantum chemistry calculations by only 4% at T=5000 K.

  9. Accurate dynamics in an azimuthally-symmetric accelerating cavity

    NASA Astrophysics Data System (ADS)

    Appleby, R. B.; Abell, D. T.

    2015-02-01

    We consider beam dynamics in azimuthally-symmetric accelerating cavities, using the EMMA FFAG cavity as an example. By fitting a vector potential to the field map, we represent the linear and non-linear dynamics using truncated power series and mixed-variable generating functions. The analysis provides an accurate model for particle trajectories in the cavity, reveals potentially significant and measurable effects on the dynamics, and shows differences between cavity focusing models. The approach provides a unified treatment of transverse and longitudinal motion, and facilitates detailed map-based studies of motion in complex machines like FFAGs.

  10. Symmetric Cryptography Asymmetric Cryptography

    E-print Network

    Ramkumar, Mahalingam

    Outline Symmetric Cryptography Asymmetric Cryptography Key Management Network Security Cryptography Symmetric Cryptography Asymmetric Cryptography Key Management Network Security 1 Symmetric Cryptography Symmetric Cryptography Overview Block Cipher Modes Multiple Encryption Hash Functions Message Authentication

  11. T-Matrix Modeling of Linear Depolarization by Morphologically Complex Soot and Soot-Containing Aerosols

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael I.; Liu, Li; Mackowski, Daniel W.

    2013-01-01

    We use state-of-the-art public-domain Fortran codes based on the T-matrix method to calculate orientation and ensemble averaged scattering matrix elements for a variety of morphologically complex black carbon (BC) and BC-containing aerosol particles, with a special emphasis on the linear depolarization ratio (LDR). We explain theoretically the quasi-Rayleigh LDR peak at side-scattering angles typical of low-density soot fractals and conclude that the measurement of this feature enables one to evaluate the compactness state of BC clusters and trace the evolution of low-density fluffy fractals into densely packed aggregates. We show that small backscattering LDRs measured with groundbased, airborne, and spaceborne lidars for fresh smoke generally agree with the values predicted theoretically for fluffy BC fractals and densely packed near-spheroidal BC aggregates. To reproduce higher lidar LDRs observed for aged smoke, one needs alternative particle models such as shape mixtures of BC spheroids or cylinders.

  12. The new WAsP flow model: a fast, linearized Mixed Spectral-Integration model applicable to complex terrain

    E-print Network

    The new WAsP flow model: a fast, linearized Mixed Spectral- Integration model applicable to complex on a commercial scale on personal computers. The Wind Atlas Analysis and Application Program (WAsP) [1. The current WAsP model for flow over orography is very quick, and accurate in flat to mildly undulating

  13. Introduction: Language attrition as a complex, non-linear development Monika S. Schmid, Barbara Kpke, Kees de Bot

    E-print Network

    Paris-Sud XI, Université de

    Introduction: Language attrition as a complex, non-linear development Monika S. Schmid, Barbara). Attitudes can thus interact with input in shaping the growth of language knowledge. Where L1 attrition, change or loss. As Roger Andersen put it thirty years ago, "[l]anguage attrition is a special case

  14. Temporal linear mode complexity as a surrogate measure of the anesthetic drug effects during sevoflurane anesthesia

    PubMed Central

    Choi, Byung-Moon; Koh, Eun-Hyo; Kim, Mun-Gyu; Kim, Sang-Ho; Noh, Gyu-Jeong

    2013-01-01

    Background The aims of this study were to compare the stability, correlation with end-tidal sevoflurane, and area below the effect (AUCeffect) vs. time curves of temporal linear mode complexity (TLMC) and approximate entropy (ApEn) during sevoflurane anesthesia. Another study goal was to characterize the time course of the effects of sevoflurane. Methods Electroencephalogram (EEG) parame1ter stability was evaluated using the coefficients of variation (CV) of the median baseline (E0), maximal (Emax), and individual median E0 - Emax values. Correlations between sevoflurane concentration and EEG parameters were tested. AUCeffect vs. time curves of TLMC and ApEn were calculated to quantitate any decrease in central nervous system activities. A sigmoid Emax model was used for pharmacodynamic modeling. Results TLMC and ApEn demonstrated CVs of 8.36 and 7.35 (for E0) and 19.61 and 13.45 (Emax), respectively. The CVs of the individual median E0 - Emax values were 65.16 for TLMC and 59.97 for ApEn. The Spearman correlation coefficient was -0.3103 for TLMC and -0.3410 for ApEn (P < 0.001 for both parameters). The median AUCeffect value was 338.9 for TLMC and 246.5 for ApEn (P = 0.457). The final pharmacodynamic parameters estimated by sigmoid Emax models were described as follows; E0: 0.614, 0.617, Emax: 0.334, 0.287, Ce50: 5.48, 5.07 vol%, ?: 1.88, 2.01, ke0: 0.306, 0.236 min (TLMC, ApEn). Conclusions TLMC is comparable to ApEn according to the univariate EEG descriptors of the effects of sevoflurane. A sigmoid Emax model well described the pharmacodynamics of sevoflurane for TLMC and ApEn. PMID:24363840

  15. Differential Dynamic Engagement within 24 SH3 Domain: Peptide Complexes Revealed by Co-Linear Chemical Shift Perturbation Analysis

    PubMed Central

    Stollar, Elliott J.; Lin, Hong; Davidson, Alan R.; Forman-Kay, Julie D.

    2012-01-01

    There is increasing evidence for the functional importance of multiple dynamically populated states within single proteins. However, peptide binding by protein-protein interaction domains, such as the SH3 domain, has generally been considered to involve the full engagement of peptide to the binding surface with minimal dynamics and simple methods to determine dynamics at the binding surface for multiple related complexes have not been described. We have used NMR spectroscopy combined with isothermal titration calorimetry to comprehensively examine the extent of engagement to the yeast Abp1p SH3 domain for 24 different peptides. Over one quarter of the domain residues display co-linear chemical shift perturbation (CCSP) behavior, in which the position of a given chemical shift in a complex is co-linear with the same chemical shift in the other complexes, providing evidence that each complex exists as a unique dynamic rapidly inter-converting ensemble. The extent the specificity determining sub-surface of AbpSH3 is engaged as judged by CCSP analysis correlates with structural and thermodynamic measurements as well as with functional data, revealing the basis for significant structural and functional diversity amongst the related complexes. Thus, CCSP analysis can distinguish peptide complexes that may appear identical in terms of general structure and percent peptide occupancy but have significant local binding differences across the interface, affecting their ability to transmit conformational change across the domain and resulting in functional differences. PMID:23251481

  16. Differential dynamic engagement within 24 SH3 domain: peptide complexes revealed by co-linear chemical shift perturbation analysis.

    PubMed

    Stollar, Elliott J; Lin, Hong; Davidson, Alan R; Forman-Kay, Julie D

    2012-01-01

    There is increasing evidence for the functional importance of multiple dynamically populated states within single proteins. However, peptide binding by protein-protein interaction domains, such as the SH3 domain, has generally been considered to involve the full engagement of peptide to the binding surface with minimal dynamics and simple methods to determine dynamics at the binding surface for multiple related complexes have not been described. We have used NMR spectroscopy combined with isothermal titration calorimetry to comprehensively examine the extent of engagement to the yeast Abp1p SH3 domain for 24 different peptides. Over one quarter of the domain residues display co-linear chemical shift perturbation (CCSP) behavior, in which the position of a given chemical shift in a complex is co-linear with the same chemical shift in the other complexes, providing evidence that each complex exists as a unique dynamic rapidly inter-converting ensemble. The extent the specificity determining sub-surface of AbpSH3 is engaged as judged by CCSP analysis correlates with structural and thermodynamic measurements as well as with functional data, revealing the basis for significant structural and functional diversity amongst the related complexes. Thus, CCSP analysis can distinguish peptide complexes that may appear identical in terms of general structure and percent peptide occupancy but have significant local binding differences across the interface, affecting their ability to transmit conformational change across the domain and resulting in functional differences. PMID:23251481

  17. Two C3 -symmetric Dy3III complexes with triple di-?-methoxo-?-phenoxo bridges, magnetic ground state, and single-molecule magnetic behavior.

    PubMed

    Hänninen, Mikko M; Mota, Antonio J; Aravena, Daniel; Ruiz, Eliseo; Sillanpää, Reijo; Camón, Agustín; Evangelisti, Marco; Colacio, Enrique

    2014-07-01

    Two series of isostructural C(3)-symmetric Ln(3) complexes Ln(3)?[BPh(4)] and Ln(3)?0.33[Ln(NO(3))(6)] (in which Ln(III) =Gd and Dy) have been prepared from an amino-bis(phenol) ligand. X-ray studies reveal that Ln(III) ions are connected by one ?(2)-phenoxo and two ?(3)-methoxo bridges, thus leading to a hexagonal bipyramidal Ln(3)O(5) bridging core in which Ln(III) ions exhibit a biaugmented trigonal-prismatic geometry. Magnetic susceptibility studies and ab initio complete active space self-consistent field (CASSCF) calculations indicate that the magnetic coupling between the Dy(III) ions, which possess a high axial anisotropy in the ground state, is very weakly antiferromagnetic and mainly dipolar in nature. To reduce the electronic repulsion from the coordinating oxygen atom with the shortest Dy-O distance, the local magnetic moments are oriented almost perpendicular to the Dy(3) plane, thus leading to a paramagnetic ground state. CASSCF plus restricted active space state interaction (RASSI) calculations also show that the ground and first excited state of the Dy(III) ions are separated by approximately 150 and 177?cm(-1), for Dy(3)?[BPh(4)] and Dy(3)?0.33[Dy(NO(3))(6)], respectively. As expected for these large energy gaps, Dy(3)?[BPh(4)] and Dy(3)?0.33[Dy(NO(3)(6)] exhibit, under zero direct-current (dc) field, thermally activated slow relaxation of the magnetization, which overlap with a quantum tunneling relaxation process. Under an applied Hdc field of 1000?Oe, Dy(3)?[BPh(4)] exhibits two thermally activated processes with U(eff) values of 34.7 and 19.5?cm(-1), whereas Dy(3)?0.33[Dy(NO(3))(6)] shows only one activated process with Ueff =19.5?cm(-1). PMID:24890335

  18. The crystal field theory for D 2d symmetric complexes and the splitting of d-orbitals of Mo 5+ in Mo[S 2 CN(C 2 H 5 ) 2 ] 4 I 3

    Microsoft Academic Search

    Yang Jian-Hua; Zhou Kang-Wei

    1989-01-01

    The energy order assignment of the d-orbitals of Mo5+ in Mo[S2CN(C2H5)2]4I3 given by Jasimet al. (1985) is restudied and corrected. It is indicated that, in general, the energy order of the d-orbitals of D2d symmetric complexes is depending on the bond angles and bond lengths of the ligands, thus there cannot be any universal energy order.

  19. Design, Activity, and 2.8 overset{circ}{A} Crystal Structure of a C_2 Symmetric Inhibitor Complexed to HIV1 Protease

    Microsoft Academic Search

    John Erickson; David J. Neidhart; John Vandrie; Dale J. Kempf; Xiu Chun Wang; Daniel W. Norbeck; Jacob J. Plattner; Judith W. Rittenhouse; Mary Turon; Norman Wideburg; William E. Kohlbrenner; Robert Simmer; Rosalind Helfrich; Deborah A. Paul; Mark Knigge

    1990-01-01

    A two-fold (C_2) symmetric inhibitor of the protease of human immunodeficiency virus type-1 (HIV-1) has been designed on the basis of the three-dimensional symmetry of the enzyme active site. The symmetric molecule inhibited both protease activity and acute HIV-1 infection in vitro, was at least 10,000-fold more potent against HIV-1 protease than against related enzymes, and appeared to be stable

  20. On Symmetric Signatures Holographic Algorithms

    E-print Network

    Cai, Jin-Yi

    recently introduced a beautiful theory called holographic algorithms. Holographic algorithms are custom nodes. 10 #12;Linear bases transformations The first ingredient of the theory of holographic algorithmsOn Symmetric Signatures in Holographic Algorithms Jin-Yi Cai University of Wisconsin, Madison

  1. Smoothed analysis of condition numbers and complexity implications for linear programming

    Microsoft Academic Search

    John Dunagan; Daniel A. Spielman; Shang-Hua Teng

    2011-01-01

    We perform a smoothed analysis of Renegar's condition number for linear programming by analyzing the distribution of the distance to ill-posedness of a linear program subject to a slight Gaussian perturbation. In particular, we show that for every n-by-d matrix ¯

  2. Average case complexity results for a centering algorithm for linear programming problems under Gaussian distributions

    Microsoft Academic Search

    Petra Huhn; Verena Wehlitz

    2009-01-01

    To solve linear programming problems by interior point methods an approximately centered interior point has to be known. Such a point can be found by an algorithmic approach – a so-called phase 1 algorithm or centering algorithm. For random linear programming problems distributed according to the rotation symmetry model, especially with normal distribution, we present probabilistic results on the quality

  3. Simply Symmetric

    ERIC Educational Resources Information Center

    de Villiers, Michael

    2011-01-01

    Symmetry is found in the visual arts, architecture and design of artefacts since the earliest time. Many natural objects, both organic and inorganic, display symmetry: from microscopic crystals and sub-atomic particles to macro-cosmic galaxies. Today it features strongly in higher mathematics such as Linear and Abstract Algebra, Projective and…

  4. Computing Linear Harmonic Unsteady Flows in Turbomachines with Complex Iterative Solvers

    E-print Network

    Giles, Mike

    of the linear harmonic Euler/Navier-Stokes solver of the HYDRA suite of parallel FORTRAN codes consists is used, to fully- coupled nonlinear three-dimensional unsteady viscous methods3 in which the structural

  5. Lipophilic platinum complexes entrapped in liposomes: improved stability and preserved antitumor activity with complexes containing linear alkyl carboxylato leaving groups

    Microsoft Academic Search

    Roman Perez-Soler; Insook Han; Salaam Al-Baker; Abdul R. Khokhar

    1994-01-01

    Lipophilic diaminocyclohexane (DACH) platinum complexes have shown significant promise in preclinical studies. One of these compounds, cis-bis-neodecanoato- trans-R,R-1,2-diaminocyclohexaneplatinum(II) (NDDP), which contains two branched leaving groups of 10 carbons, showed a favorable toxicity profile in a liposomal formulation in early clinical trials. However, like many other DACH platinum compounds with branched leaving groups, it is unstable within the liposomes, thus preventing

  6. Lipophilic platinum complexes entrapped in liposomes: improved stability and preserved antitumor activity with complexes containing linear alkyl carboxylato leaving groups

    Microsoft Academic Search

    Roman Perez-Solerl; Insook Hanl; Salaam Al-Baker; Abdul R. Khokhar

    1994-01-01

    Lipophilic diaminocyclohexane (DACH) platinum complexes have shown significant promise in preclinical studies. One of these compounds,cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexaneplatinum(II) (NDDP), which contains two branched leaving groups of 10 carbons, showed a favorable toxicity profile in a liposomal formulation in early clinical trials. However, like many other DACH platinum compounds with branched leaving groups, it is unstable within the liposomes, thus preventing its widespread

  7. Probabilistic cloning of three symmetric states

    SciTech Connect

    Jimenez, O. [Center for Optics and Photonics, Departamento de Fisica, Universidad de Concepcion, Casilla 4016, Concepcion (Chile); Departamento de Fisica, Facultad de Ciencias Basicas, Universidad de Antofagasta, Casilla 170, Antofagasta (Chile); Bergou, J. [Department of Physics, Hunter College, City University of New York, 695 Park Avenue, New York, New York 10021 (United States); Delgado, A. [Center for Optics and Photonics, Departamento de Fisica, Universidad de Concepcion, Casilla 4016, Concepcion (Chile); Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)

    2010-12-15

    We study the probabilistic cloning of three symmetric states. These states are defined by a single complex quantity, the inner product among them. We show that three different probabilistic cloning machines are necessary to optimally clone all possible families of three symmetric states. We also show that the optimal cloning probability of generating M copies out of one original can be cast as the quotient between the success probability of unambiguously discriminating one and M copies of symmetric states.

  8. Symmetric and Hermitian In this chapter, we discuss the special classes of symmetric and Hermitian matrices.

    E-print Network

    Kilmer, Misha Elena

    that aij = ¯aji for every i, j pair. Thus, the diagonal of a Hermitian matrix must be real. Definition 5 meanings. There is such a thing as a complex-symmetric matrix (aij = aji) - a complex symmetric matrix need

  9. Linear Motif-Mediated Interactions Have Contributed to the Evolution of Modularity in Complex Protein Interaction Networks

    PubMed Central

    Kim, Inhae; Lee, Heetak; Han, Seong Kyu; Kim, Sanguk

    2014-01-01

    The modular architecture of protein-protein interaction (PPI) networks is evident in diverse species with a wide range of complexity. However, the molecular components that lead to the evolution of modularity in PPI networks have not been clearly identified. Here, we show that weak domain-linear motif interactions (DLIs) are more likely to connect different biological modules than strong domain-domain interactions (DDIs). This molecular division of labor is essential for the evolution of modularity in the complex PPI networks of diverse eukaryotic species. In particular, DLIs may compensate for the reduction in module boundaries that originate from increased connections between different modules in complex PPI networks. In addition, we show that the identification of biological modules can be greatly improved by including molecular characteristics of protein interactions. Our findings suggest that transient interactions have played a unique role in shaping the architecture and modularity of biological networks over the course of evolution. PMID:25299147

  10. Haptic rendering of complex deformations through handle-space force linearization

    Microsoft Academic Search

    Carlos Garre; Miguel A. Otaduy

    2009-01-01

    The force-update-rate requirements of transparent rendering of vir- tual environments are in conflict with the computational cost re- quired for computing complex interactions between deforming ob- jects. In this paper we introduce a novel method for satisfying high force update rates with deformable objects, yet retaining the visual quality of complex deformations and interactions. The objects that are haptically manipulated

  11. A dense out-of-core solver (DOCS) for complex-valued linear systems

    SciTech Connect

    Lee, Cullen E.

    1998-09-01

    Dense systems of linear equations are quite common in many science and engineering applications. Such linear systems place extreme storage and computational demands on computer resources and, in many cases, may severely limit the subsequent analysis. A dense out-of-core solver (DOCS) that operates on a partitioned coefficient matrix can reduce the in-core storage requirements of the linear system while spreading the associated computational burden over multiple processors (which reduces run time as well). In this report, I describe a DOCS that operates on a partitioned coefficient matrix that maybe distributed over multiple external storage devices. I have implemented this solver using Message-Passing Interface (MPI) protocols. This report presents petiormance data from a series of run time trials that compare the run time of both sequential and parallel implementations of the DOCS.

  12. Differences between stress and strain control in the non-linear behavior of complex fluids

    Microsoft Academic Search

    Jörg Läuger; Heiko Stettin

    2010-01-01

    Various techniques have been proposed to characterize the behavior in the non-linear regime. A new theoretical framework,\\u000a as proposed recently by Ewoldt et al. (J Rheol 52(6):1427–1458, 2008), provides a quantitative analysis of Lissajous figures during large-amplitude oscillatory shear (LAOS). Intra- and intercycle\\u000a non-linearities, strain stiffening and softening, and shear thinning and thickening are described and can be distinguished.\\u000a The new

  13. Spectral Norm of Symmetric Functions

    E-print Network

    Ada, Anil; Hatami, Hamed

    2012-01-01

    The spectral norm of a Boolean function $f:\\{0,1\\}^n \\to \\{-1,1\\}$ is the sum of the absolute values of its Fourier coefficients. This quantity provides useful upper and lower bounds on the complexity of a function in areas such as learning theory, circuit complexity, and communication complexity. In this paper, we give a combinatorial characterization for the spectral norm of symmetric functions. We show that the logarithm of the spectral norm is of the same order of magnitude as $r(f)\\log(n/r(f))$ where $r(f) = \\max\\{r_0,r_1\\}$, and $r_0$ and $r_1$ are the smallest integers less than $n/2$ such that $f(x)$ or $f(x) \\cdot parity(x)$ is constant for all $x$ with $\\sum x_i \\in [r_0, n-r_1]$. We mention some applications to the decision tree and communication complexity of symmetric functions.

  14. A low-complexity linear and iterative receiver architecture for multi-antenna communication systems

    E-print Network

    Milliner, David Louis, 1981-

    2004-01-01

    Multi-antenna systems have been shown to significantly improve channel capacity in wireless environments. The focus of this thesis is on the design of low-complexity multi-antenna receiver architectures for communication ...

  15. Scaled Langevin equation for complex systems: New linear scaling relation for weight factor

    Microsoft Academic Search

    S. Fujita; S. S. Lee; J. Koyama

    1997-01-01

    A set of scaled Langevin equations is proposed to study a long time tail of correlation functions for two model systems (Type I and Type II). Each system is composed of elements which are grouped into clusters according to dynamical activations for external forces. The clusters in Type I are characterized by linear scaling rules in repetitive operations, whereas the

  16. Estimation of Complex Generalized Linear Mixed Models for Measurement and Growth

    ERIC Educational Resources Information Center

    Jeon, Minjeong

    2012-01-01

    Maximum likelihood (ML) estimation of generalized linear mixed models (GLMMs) is technically challenging because of the intractable likelihoods that involve high dimensional integrations over random effects. The problem is magnified when the random effects have a crossed design and thus the data cannot be reduced to small independent clusters. A…

  17. Discrete site surface complexation constants for lanthanide adsorption to bacteria as determined by experiments and linear free energy relationships.

    PubMed

    Ngwenya, Bryne T; Magennis, Marisa; Olive, Valerie; Mosselmans, J Fred W; Ellam, Robert M

    2010-01-15

    Bacteria are abundant in many natural and engineered environments where they are thought to exert important controls on the cycling, mobility, bioavailability, and toxicity of metal contaminants. In order to probe their role in moderating the behavior of lanthanides, pH-dependent adsorption edges of 13 individual lanthanides and yttrium to the Gram-negative bacterium Pantoea agglomerans were used to generate discrete site surface complexation constants. The calculated surface complexation constants were compared with stability constants estimated using linear free energy relationships based on a number of hydroxyl-containing ligands. The experimental data suggests that lanthanide adsorption edges below pH 6.5 are consistent with adsorption to phosphate groups for the light and some of the middle lanthanides (La to Gd), whereas some of the middle and heavy lanthanides appear to favor carboxyl co-ordination (Tb to Yb), although exceptions occur in each grouping. The experimentally derived surface complexation constants for carboxyl coordination were of similar magnitude to stability constants estimated from linear free energy correlations using fulvic acid stability constants. The implication is that the adsorption of lanthanides to bacterial surfaces could be modeled reasonably well using lanthanide stability constants for natural organic matter, except perhaps at low pH where phosphate binding dominates. PMID:20000843

  18. Crystal structure of a symmetric football-shaped GroEL:GroES2-ATP14 complex determined at 3.8Å reveals rearrangement between two GroEL rings.

    PubMed

    Koike-Takeshita, Ayumi; Arakawa, Takatoshi; Taguchi, Hideki; Shimamura, Tatsuro

    2014-10-23

    The chaperonin GroEL is an essential chaperone that assists in protein folding with the aid of GroES and ATP. GroEL forms a double-ring structure, and both rings can bind GroES in the presence of ATP. Recent progress on the GroEL mechanism has revealed the importance of a symmetric 1:2 GroEL:GroES2 complex (the "football"-shaped complex) as a critical intermediate during the functional GroEL cycle. We determined the crystal structure of the football GroEL:GroES2-ATP14 complex from Escherichia coli at 3.8Å, using a GroEL mutant that is extremely defective in ATP hydrolysis. The overall structure of the football complex resembled the GroES-bound GroEL ring of the asymmetric 1:1 GroEL:GroES complex (the "bullet" complex). However, the two GroES-bound GroEL rings form a modified interface by an ~7° rotation about the 7-fold axis. As a result, the inter-ring contacts between the two GroEL rings in the football complex differed from those in the bullet complex. The differences provide a structural basis for the apparently impaired inter-ring negative cooperativity observed in several biochemical analyses. PMID:25174333

  19. Separation of fetal and maternal ECG complexes from a mixed signal using an algorithm based on linear regression.

    PubMed

    Genevier, E S; Deans, A C; Carter, M C; Steer, P J

    1995-10-01

    Fetal scalp ECG and Doppler ultrasound are the two methods universally used to derive the fetal heart rate (FHR) for cardiotocography. Other fetal signal sources have not been used successfully because of the complexity of the signal and the need for an additional maternal ECG input. In this paper, we present an algorithm for separating the fetal and maternal ECG signals obtained from intrauterine electrodes during labour. The algorithm detects all occurrences of ECG complexes and uses linear regression functions to compare each complex with a set templates. Sets of templates are identified as either maternal or fetal in origin and two signals are output for heart rate measurement. The outputs are also processed to eliminate artefacts that may occur when the maternal and fetal complexes are coincident. The algorithm processes 10 seconds of data at a time (in about 200 ms on a standard PC) while a further 10 s of data is being acquired. It has the advantage that no extra input is required, such as maternal ECG obtained from chest leads, and only assumes that two different populations of complexes of two different shapes are present in the input signal. The algorithm could also be used for the separation of fetal and maternal signals obtained from abdominal electrodes. PMID:7489124

  20. Fully linear reconstruction method for fluorescence yield and lifetime through inverse complex-source formulation: simulation studies

    PubMed Central

    Gao, Hao; Lin, Yuting; Gulsen, Gultekin; Zhao, Hongkai

    2014-01-01

    In fluorescence imaging, both fluorescence yield and lifetime are of great importance. Traditionally, with the frequency-domain data, two parameters can be directly recovered through a nonlinear formulation. However, the reconstruction accuracy highly depends on initial guesses. To overcome this hurdle, we propose the linear scheme via an inverse complex-source formulation. Using the real and imaginary parts of the frequency-domain data, the proposed method is fully linear; it is not sensitive to initial guesses and is stable with high-level noise. Meanwhile, the algorithm is efficient, and the reconstruction takes one or a few iterations. In addition, the colocalization constraint due to the unique feature of fluorescence imaging is imposed to enhance algorithm performance. The algorithms are tested with simulated data. PMID:20517455

  1. Ruthenium-complex-catalyzed regio- and stereoselective linear codimerization of 2-norbornenes with acrylic compounds.

    PubMed

    Ura, Yasuyuki; Tsujita, Hiroshi; Wada, Kenji; Kondo, Teruyuki; Mitsudo, Take-aki

    2005-08-19

    A linear codimerization of 2-norbornenes with acrylic compounds such as acrylates and an acrylamide proceeded efficiently by ruthenium catalyst systems, RuCl3(tpy)/Zn (tpy = 2,2':6',2' '-terpyridine) or [RuCl2(C6H6)]2/Zn in a primary or secondary alcoholic solvent, to afford the corresponding exo-trans-2-norbornylacrylates as major products regio- and stereoselectively along with a small amount of cis isomers. The reaction of 2,5-norbornadiene with methyl acrylate also gave the linear exo-trans codimer, which was effectively catalyzed by the addition of triarylphosphines to the RuCl3(tpy)/Zn catalyst system. PMID:16095279

  2. A (Not Really) Complex Method for Finding Solutions to Linear Differential Equations. Modules and Monographs in Undergraduate Mathematics and Its Applications Project. UMAP Unit 497.

    ERIC Educational Resources Information Center

    Uebelacker, James W.

    This module considers ordinary linear differential equations with constant coefficients. The "complex method" used to find solutions is discussed, with numerous examples. The unit includes both problem sets and an exam, with answers provided for both. (MP)

  3. On the worst case complexity of potential reduction algorithms for linear programming

    Microsoft Academic Search

    Dimitris Bertsimas; Xiaodong Luo

    1997-01-01

    There are several classes of interior point algorithms that solve linear programming problems in O(x\\/ffL) iterations. Among them, several potential reduction algorithms combine both theoretical (o(vr~L) iterations) and practical efficiency as they allow the flexibility of line searches in the potential function, and thus can lead to practical implementations. It is a significant open question whether interior point algorithms can

  4. A new method for predicting response in complex linear systems. II. [under random or deterministic steady state excitation

    NASA Technical Reports Server (NTRS)

    Bogdanoff, J. L.; Kayser, K.; Krieger, W.

    1977-01-01

    The paper describes convergence and response studies in the low frequency range of complex systems, particularly with low values of damping of different distributions, and reports on the modification of the relaxation procedure required under these conditions. A new method is presented for response estimation in complex lumped parameter linear systems under random or deterministic steady state excitation. The essence of the method is the use of relaxation procedures with a suitable error function to find the estimated response; natural frequencies and normal modes are not computed. For a 45 degree of freedom system, and two relaxation procedures, convergence studies and frequency response estimates were performed. The low frequency studies are considered in the framework of earlier studies (Kayser and Bogdanoff, 1975) involving the mid to high frequency range.

  5. Two dimensional symmetric correlation functions of the {hat S} operator and two dimensional Fourier transforms: Considering the line coupling for P and R lines of linear molecules

    NASA Astrophysics Data System (ADS)

    Ma, Q.; Boulet, C.; Tipping, R. H.

    2014-03-01

    The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the {hat S} operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements.

  6. Two Dimensional Symmetric Correlation Functions of the S Operator and Two Dimensional Fourier Transforms: Considering the Line Coupling for P and R Lines of Linear Molecules

    NASA Technical Reports Server (NTRS)

    Ma, Q.; Boulet, C.; Tipping, R. H.

    2014-01-01

    The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the ^S operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements.

  7. Two dimensional symmetric correlation functions of the ? operator and two dimensional Fourier transforms: considering the line coupling for P and R lines of linear molecules.

    PubMed

    Ma, Q; Boulet, C; Tipping, R H

    2014-03-14

    The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the ? operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements. PMID:24628166

  8. Symmetric Novikov superalgebras

    SciTech Connect

    Ayadi, Imen; Benayadi, Saied [Laboratoire de Mathematiques et Applications de Metz, CNRS-UMR 7122, Universite Paul Verlaine-Metz, Ile du Saulcy, F-57045 Metz Cedex 1 (France)

    2010-02-15

    We study Novikov superalgebras with nondegenerate associative supersymmetric bilinear forms which are called symmetric Novikov superalgebras. We show that Novikov symmetric superalgebras are associative superalgebras with additional condition. Several examples of symmetric Novikov superalgebras are included, in particular, examples of symmetric Novikov superalgebras which are not 2-nilpotent. Finally, we introduce some notions of double extensions in order to give inductive descriptions of symmetric Novikov superalgebras.

  9. Minimally symmetric Higgs boson

    NASA Astrophysics Data System (ADS)

    Low, Ian

    2015-06-01

    Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized S U (2 )L×U (1 )Y electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective Lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal among all models where the Higgs arises as a pseudo-Nambu-Goldstone boson. Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.

  10. A Family of Linear Complexity Likelihood Ascent Search Multiuser Detectors for CDMA Communications

    E-print Network

    Sun, Yi

    . However, its computational complexity grows exponentially with the number of active users. Many low a family of modified Hopfield neural network algorithms [6] with the earliest application to image and metric Consider a bit-synchronous CDMA Gaussian channel of K users. The received one-shot signal

  11. Accelerating simulations of first principle models of complex industrial systems using quasi linear parameter varying models

    Microsoft Academic Search

    Robert Bos; Xavier Bombois; Paul M. J. Van den Hof

    2005-01-01

    First principles models of complex industrial processes are often derived using finite element or finite difference methods. One of the advantages of these models is that the states in the model have a clear physical interpretation. Using such models we can attempt to monitor or control selected physical quantities, even though they may not be directly measurable. Unfortunately the CPU

  12. Controlled loading of cryoprotectants (CPAs) to oocyte with linear and complex CPA profiles on a microfluidic platform†

    PubMed Central

    Heo, Yun Seok; Lee, Ho-Joon; Hassell, Bryan A.; Irimia, Daniel; Toth, Thomas L.; Elmoazzen, Heidi; Toner, Mehmet

    2013-01-01

    Oocyte cryopreservation has become an essential tool in the treatment of infertility by preserving oocytes for women undergoing chemotherapy. However, despite recent advances, pregnancy rates from all cryopreserved oocytes remain low. The inevitable use of the cryoprotectants (CPAs) during preservation affects the viability of the preserved oocytes and pregnancy rates either through CPA toxicity or osmotic injury. Current protocols attempt to reduce CPA toxicity by minimizing CPA concentrations, or by minimizing the volume changes via the step-wise addition of CPAs to the cells. Although the step-wise addition decreases osmotic shock to oocytes, it unfortunately increases toxic injuries due to the long exposure times to CPAs. To address limitations of current protocols and to rationally design protocols that minimize the exposure to CPAs, we developed a microfluidic device for the quantitative measurements of oocyte volume during various CPA loading protocols. We spatially secured a single oocyte on the microfluidic device, created precisely controlled continuous CPA profiles (step-wise, linear and complex) for the addition of CPAs to the oocyte and measured the oocyte volumetric response to each profile. With both linear and complex profiles, we were able to load 1.5 M propanediol to oocytes in less than 15 min and with a volumetric change of less than 10%. Thus, we believe this single oocyte analysis technology will eventually help future advances in assisted reproductive technologies and fertility preservation. PMID:21887438

  13. A new complexity result on multiobjective linear integer programming using short rational generating functions

    Microsoft Academic Search

    Víctor Blanco; Justo Puerto

    This paper presents a new complexity result for solving multiobjective integer programming problems. We prove that encoding\\u000a the entire set of nondominated solutions of the problem in a short sum of rational functions is polynomially doable, when\\u000a the dimension of the decision space is fixed. This result extends a previous result presented in De Loera et al. (INFORMS\\u000a J. Comput. 21(1):39–48,

  14. Linear free energy relations and solvent effects for complexes of m-cresol and various bases

    SciTech Connect

    Spencer, J.N.; Allott, K.N.; Chanandin, S.; Enders, B.G.; Grushow, A.; Kneizys, S.P.; Mobley, D.; Naghdi, J.; Patti, L.M.; Salata, J.S. (Franklin and Marshall College, Lancaster, PA (USA))

    1988-03-01

    The enthalpies, entropies, and equilibrium constants for the hydrogen bonded complexes of m-cresol with ten bases in cyclohexane solvent have been determined by calorimetric and spectroscopic methods. The logarithm of the equilibrium constant correlates well with the dipole moment of the base and the solvatochromic parameter {beta} which measures the electron donating ability of the base. The enthalpy and entropy data show that the dipole term does not enter into the log K correlation as a consequence of electrostatic interactions between acid and base in the complex. The free base-solvent interaction, which appears to be dipolar in origin, reduces the entropy of the free base and hence contributes to a favorable entropy change for complex formation. The present data are compared to previously reported data obtained in CCl{sub 4} solvent. Solvent effects on the thermodynamic parameters in CCl{sub 4} and cyclohexane appear to be related to dipolar interactions by m-cresol and the bases with the two solvents.

  15. Affine Stanley symmetric functions for classical types

    E-print Network

    Pon, Steven

    2011-01-01

    We introduce affine Stanley symmetric functions for the special orthogonal groups, a class of symmetric functions that model the cohomology of the affine Grassmannian, continuing the work of Lam and Lam, Schilling, and Shimozono on the special linear and symplectic groups, respectively. For the odd orthogonal groups, a Hopf-algebra isomorphism is given, identifying (co)homology Schubert classes with symmetric functions. For the even orthogonal groups, we conjecture an approximate model of (co)homology via symmetric functions. In the process, we develop type B and type D non-commutative k-Schur functions as elements of the nilCoxeter algebra that model homology of the affine Grassmannian. Additionally, Pieri rules for multiplication by special Schubert classes in homology are given in both cases. Finally, we present a type-free interpretation of Pieri factors, used in the definition of noncommutative k-Schur functions or affine Stanley symmetric functions for any classical type.

  16. Linear free energy relationships for metal-ligand complexation: Bidentate binding to negatively-charged oxygen donor atoms

    NASA Astrophysics Data System (ADS)

    Carbonaro, Richard F.; Atalay, Yasemin B.; Di Toro, Dominic M.

    2011-05-01

    Stability constants for metal complexation to bidentate ligands containing negatively-charged oxygen donor atoms can be estimated from the following linear free energy relationship (LFER): log KML = ?OO( ?O log KHL,1 + ?O log KHL,2) where KML is the metal-ligand stability constant for a 1:1 complex, KHL,1 and KHL,2 are the proton-ligand stability constants (the ligand p Ka values), and ?O is the Irving-Rossotti slope. The parameter ?OO is metal specific and has slightly different values for five and six membered chelate rings. LFERs are presented for 21 different metal ions and are accurate to within approximately 0.30 log units in predictions of log KML values. Ligands selected for use in LFER development include dicarboxylic acids, carboxyphenols, and ortho-diphenols. For ortho-hydroxybenzaldehydes, ?-hydroxycarboxylic acids, and ?-ketocarboxylic acids, a modification of the LFER where log KHL,2 is set equal to zero is required. The chemical interpretation of ?OO is that it accounts for the extra stability afforded to metal complexes by the chelate effect. Cu-NOM binding constants calculated from the bidentate LFERs are similar in magnitude to those used in WHAM 6. This LFER can be used to make log KML predictions for small organic molecules. Since natural organic matter (NOM) contains many of the same functional groups (i.e. carboxylic acids, phenols, alcohols), the LFER log KML predictions shed light on the range of appropriate values for use in modeling metal partitioning in natural systems.

  17. Optimal symmetric flight studies

    NASA Technical Reports Server (NTRS)

    Weston, A. R.; Menon, P. K. A.; Bilimoria, K. D.; Cliff, E. M.; Kelley, H. J.

    1985-01-01

    Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory.

  18. Localization of c-di-GMP-Binding Protein with the Linear Terminal Complexes of Acetobacter xylinum

    PubMed Central

    Kimura, Satoshi; Chen, He Ping; Saxena, Inder M.; Brown, R. Malcolm; Itoh, Takao

    2001-01-01

    Specific labeling of a single row of cellulose-synthesizing complexes (terminal complexes, TC subunits, TCs, or TC arrays) in Acetobacter xylinum by antibodies raised against a 93-kDa protein (the cyclic dignanylic acid-binding protein) has been demonstrated by using the sodium dodecyl sulfate (SDS)–freeze-fracture labeling (FRL) technique. The antibodies to the 93-kDa protein specifically recognized the TC subunits on the protoplasmic fracture (PF) face of the outer membrane in A. xylinum; however, nonlabeled TCs were also observed. Two types of TC subunits (particles or pits) are observed on the PF face of the outer membrane: (i) immunogold-labeled TCs showing a line of depressions (pits) with an indistinct particle array and (ii) nonlabeled TC subunits with a distinct single row of particle arrays. The evidence indicates that the labeling patterns differ with respect to the presence or absence of certain TC subunits remaining attached to the replica after SDS treatment. This suggests the presence of at least two TC components, one in the outer membrane and the other in the cytoplasmic membrane. If the TC component in the outer membrane is preferentially fractured and remains attached to the ectoplasmic fracture face (or outer leaflet) of the outer membrane, subsequent replica formation reveals a pit or depression with positive antibody labeling on the PF face of the outer membrane. If the TC component in the outer membrane remains with the PF face (or inner leaflet) of the outer membrane, the innermost TC component is removed during SDS treatment and labeling does not occur. SDS-FRL of TCs in A. xylinum has enabled us to provide the first topological molecular analysis of component proteins in a cellulose-synthesizing TC structure in a prokaryotic organism. PMID:11544230

  19. Symmetric Cryptography Asymmetric Cryptography

    E-print Network

    Ramkumar, Mahalingam

    Outline Trust Symmetric Cryptography Asymmetric Cryptography Key Management Network Security Cryptography - A Review Mahalingam Ramkumar Mississippi State University, MS September 22, 2006 Ramkumar Review #12;Outline Trust Symmetric Cryptography Asymmetric Cryptography Key Management Network Security 1

  20. Synthesis and characterization of Cu(II) complexes of tetradentate and tridentate symmetrical Schiff base ligands involving o -phenelenediamine, salicylaldehyde and diacetylmonoxime

    Microsoft Academic Search

    Debdulal Maity; Michael G. B. Drew; Jeffrey F. Godsell; Saibal Roy; Gurucharan Mukhopadhyay

    2010-01-01

    A mononuclear complex [CuL] (1), a binuclear complex [Cu2LCl2(H2O)] (2), a trinuclear complex [Cu3L2](ClO4)2 (3) involving o-phenylenediamine and salicylaldehyde and another binuclear complex of a tridentate ligand (H2L1) [Cu2L21](CH3COO)2 (4) involving o-phenylenediamine and diacetylmonoxime have been synthesized, where H2L = N,N?-o-phenylenebis(salicylideneimine) and H2L1 = 3-(2-aminophenylimino)butan-2-one oxime. All the complexes have been characterized by elemental analyses, spectral and\\u000a magnetic studies. The binuclear complex (2) was

  1. A simple scheme for universal linear optics quantum computing with constant experimental complexity using fiber-loops

    E-print Network

    Peter P. Rohde

    2014-10-02

    Recently, Motes, Gilchrist, Dowling & Rohde [Phys. Rev. Lett. 113, 120501 (2014)] presented a scheme for photonic boson-sampling using a fiber-loop architecture. Here we show that the same architecture can be modified to implement full, universal linear optics quantum computing, in various incarnations. The scheme employs two embedded fiber-loops, a single push-button photon source, three dynamically controlled beamsplitters, and a single time-resolved photo-detector. The architecture has only a single point of interference, and thus may be significantly easier to align than other schemes. The experimental complexity of the scheme is constant, irrespective of the size of the computation, limited only by fiber lengths and their respective loss rates.

  2. Energy of gravitational radiation in plane-symmetric space-times

    E-print Network

    Sean A. Hayward

    2008-05-19

    Gravitational radiation in plane-symmetric space-times can be encoded in a complex potential, satisfying a non-linear wave equation. An effective energy tensor for the radiation is given, taking a scalar-field form in terms of the potential, entering the field equations in the same way as the matter energy tensor. It reduces to the Isaacson energy tensor in the linearized, high-frequency approximation. An energy conservation equation is derived for a quasi-local energy, essentially the Hawking energy. A transverse pressure exerted by interacting low-frequency gravitational radiation is predicted.

  3. Non-linear model for the kinetics of 10B in blood after BPA-fructose complex infusion

    NASA Astrophysics Data System (ADS)

    Ryynänen, Päivi; Kangasmäki, Aki; Hiismäki, Pekka; Coderre, Jeffrey; Diaz, Aidnag Z.; Kallio, Merja; Laakso, Juha; Kulvik, Martti; Savolainen, Sauli

    2002-03-01

    A numerical model with a memory effect was created to describe the kinetics of 10B in blood after a single 4-dihydroxyborylphenylalanine-fructose complex (BPA-F) infusion in boron neutron capture therapy (BNCT). The model formulation was based on the averaged data from 10 glioma patients from the Brookhaven National Laboratory (BNL) BNCT-trials. These patients received a 2 h i.v. infusion of a BPA-fructose complex that delivered 290 mg BPA/kg body weight. The model was validated by fitting the original BNL patient data and new patient data from the Finnish BNCT-trials. The new 3-parameter non-linear model provided mean absolute differences between the measured and estimated 10B concentrations in blood that were less than 3.9% when used to simulate actual patient irradiations that comprised two irradiation fields separated by a break to reposition the patient. The flexibility of the model was successfully tested with two different infusion protocols. The patient data were modelled with a two-compartment model and a bi-exponential fit for comparison. The 3-parameter model is better than previously described models in predicting the time course of blood 10B concentration after cessation of intravenous infusion of BPA-fructose.

  4. Modal analysis of optical fibers with symmetrically distributed nonuniform cores

    Microsoft Academic Search

    Naoto Kishi; K. Tayama; E. Yamashita

    1996-01-01

    This paper describes the modal analysis of optical fibers with symmetrically distributed multiple cores. Each core has an identical, axially symmetrical, and nonuniform refractive index profile. Group theoretical approach is applied to treat the symmetry of the waveguide structure. The point-matching method combined with the staircase-approximation method is used to take into account complex boundary conditions and complex refractive index

  5. Isospecific polymerization of 1-hexene by C1-symmetric half-metallocene dimethyl complexes of group 4 metals with bidentate N-substituted iminomethylpyrrolyl ligands.

    PubMed

    Yasumoto, Takahiro; Yamamoto, Keishi; Tsurugi, Hayato; Mashima, Kazushi

    2013-07-01

    Non-bridged half-metallocene dimethyl complexes of group 4 metals 2a-4a with an N-4-methoxyphenyl(iminomethyl)pyrrolyl ligand 1a were synthesized and characterized by NMR spectroscopy and X-ray analysis. Upon activation with [Ph3C][B(C6F5)4], these complexes became active catalysts for the polymerization of 1-hexene. A series of hafnium complexes with various N-substituents on the imine group of ligands 1b-1g were also prepared and applied as catalysts for 1-hexene polymerization. The activation parameters for the exchange process between the two methyl groups bound to the metal for Cp*MMe2(R-pyr) complexes were estimated by NMR shape analysis at various temperatures. The findings indicated that the transition state of the ligand flipping process might be associated with the isoselectivity of the polymerization reaction. PMID:23235804

  6. Solving Fuzzy Linear Programming Problems with Linear Membership Functions

    Microsoft Academic Search

    Rafail N. Gasimov

    In this paper, we concentrate on two kinds of fuzzy linear programming problems: linear programming problems with only fuzzy technological coecients and linear programming problems in which both the right-hand side and the technological coecients are fuzzy numbers. We consider here only the case of fuzzy numbers with linear membership functions. The symmetric method of Bellman and Zadeh (2) is

  7. The optical solitons in the Scarff parity-time symmetric potentials

    NASA Astrophysics Data System (ADS)

    Chen, Haibo; Hu, Sumei; Qi, Lingmin

    2014-11-01

    We investigate the existence and stability of solitons in parity-time (PT) symmetric Scarff complex potentials, including linear case, and self-focusing and self-defocusing nonlinear cases. For linear case, the PT-breaking points, the eigenvalues and eigenfunction for different modulated depths of PT symmetry Scarff complex potential are obtained numerically. For nonlinear cases, the existence and stability of fundamental and multipole solitons are studied in self-focusing and self-defocusing media. For a fixed modulated depth, the eigenvalue for fundamental or multipole linear modes is equal to the critical propagation constant bc of fundamental and multipole solitons existence. Fundamental solitons are stable in the self-defocusing nonlinear media and low power region for the self-focusing nonlinear case. Multipole solitons are stable with the propagation constants close to bc both for self-focusing and self-defocusing nonlinearities.

  8. Ligand field influence on the electronic and magnetic properties of quasi-linear two-coordinate iron(ii) complexes.

    PubMed

    Chilton, Nicholas F; Lei, Hao; Bryan, Aimee M; Grandjean, Fernande; Long, Gary J; Power, Philip P

    2015-06-28

    The 2 to 300 K magnetic susceptibilities of Fe{N(SiMe2Ph)2}2, 1, Fe{N(SiMePh2)2}2, 2, and the diaryl complex Fe(Ar(Pr(i)4))2, 3, where Ar(Pr(i)4) is C6H3-2,6(C6H3-2,6-Pr(i)2)2 have been measured. Initial fits of these properties in the absence of an independent knowledge of their ligand field splitting have proven problematic. Ab initio calculations of the CASSCF/RASSI/SINGLE-ANISO type have indicated that the orbital energies of the complexes, as well as those of Fe(Ar(Me6))2, 4, where Ar(Me6) is C6H3-2,6(C6H2-2,4,6-Me3)2), are in the order dxy? dx(2)-y(2) < dxz? dyz < dz(2), and the iron(ii) complexes in this ligand field have the (dxy, dx(2)-y(2))(3)(dxz, dyz)(2)(dz(2))(1) ground electronic configuration with a substantial orbital contribution to their effective magnetic moments. An ab initio-derived ligand field and spin-orbit model is found to yield an excellent simulation of the observed magnetic properties of 1-3. The calculated ligand field strengths of these ligands are placed in the broader context of common coordination ligands in hypothetical two-coordinate linear iron(ii) complexes. This yields the ordering I(-) < H(-) < Br(-)? PMe3 < CH3(-) < Cl(-)? C(SiMe3)3(-) < CN(-)? SAr(Pr(i)6-) < Ar(Pr(i)4-) < Ar(Me6-)? N3(-) < NCS(-)? NCSe(-)? NCBH3(-)? MeCN ? H2O ? NH3 < NO3(-)? THF ? CO ? N(SiMe2Ph)2(-)? N(SiMePh2)2(-) < F(-)? N(H)Ar(Pr(i)6-)? N(SiMe3)Dipp(-) < OAr(Pr(i)4-). The magnetic susceptibility of the bridged dimer, [Fe{N(SiMe3)2}2]2, 5, has also been measured between 2 and 300 K and a fit of ?MT with the isotropic Heisenberg Hamiltonian, ? = -2J?1·?2 yields an antiferromagnetic exchange coupling constant, J, of -131(2) cm(-1). PMID:26006177

  9. The first example of a centro-symmetrical bis(imido)-bridged dinuclear cobalt(III) complex: synthesis via oxidative dehydrogenation and phenoxazinone synthase activity.

    PubMed

    Panja, Anangamohan; Guionneau, Philippe

    2013-04-14

    A bis(imido)-bridged dinuclear cobalt(III) complex, [Co2(amp)2(?-imp)2Cl2]Cl2·2H2O () [amp = 2-aminomethylpyridine; imp = 2-iminomethylpyridine anion], was synthesized by the reaction of cobalt(II) chloride with 2-aminomethylpyridine in the presence of alkaline hydrogen peroxide at room temperature. X-ray crystallography reveals that both the metal centres in the molecule are related to each other through an inversion centre, and the geometry of each of the Co(III) ions is a distorted octahedral structure having a CoN5Cl coordination environment. The most important feature of the structure is the modification of half of the coordinated amines by the oxidative dehydrogenation process which involves double bridging in the complex cation. To the best of our knowledge, this is the first example of a bis(imido)-bridged dinuclear cobalt(III) complex derived from metal-assisted oxidative dehydrogenation of the coordinated primary amine ligand. Complex was found to be an excellent functional model for the phenoxazinone synthase, catalyzing the oxidative coupling of 2-aminophenol to the corresponding 2-aminophenoxazinone chromophore in dioxygen saturated methanol. The detailed kinetic investigations reveal that the phenoxazinone chromophore is produced via a potential complex-substrate intermediate. PMID:23396321

  10. Control of linear modes in cylindrical resistive magnetohydrodynamics with a resistive wall, plasma rotation, and complex gain

    SciTech Connect

    Brennan, D. P. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Finn, J. M. [Applied Mathematics and Plasma Physics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-10-15

    Feedback stabilization of magnetohydrodynamic (MHD) modes in a tokamak is studied in a cylindrical model with a resistive wall, plasma resistivity, viscosity, and toroidal rotation. The control is based on a linear combination of the normal and tangential components of the magnetic field just inside the resistive wall. The feedback includes complex gain, for both the normal and for the tangential components, and it is known that the imaginary part of the feedback for the former is equivalent to plasma rotation [J. M. Finn and L. Chacon, Phys. Plasmas 11, 1866 (2004)]. The work includes (1) analysis with a reduced resistive MHD model for a tokamak with finite ? and with stepfunction current density and pressure profiles, and (2) computations with a full compressible visco-resistive MHD model with smooth decreasing profiles of current density and pressure. The equilibria are stable for ??=?0 and the marginal stability values ?{sub rp,rw}?complex gain G{sub i} to optimize in the presence of rotation in this regime with ??>??{sub rp,iw} is presented. The effect of imaginary gain with tangential sensors is more complicated but essentially destabilizes above and below ?{sub rp,iw}.

  11. The pneumococcal MgaSpn virulence transcriptional regulator generates multimeric complexes on linear double-stranded DNA

    PubMed Central

    Solano-Collado, Virtu; Lurz, Rudi; Espinosa, Manuel; Bravo, Alicia

    2013-01-01

    The MgaSpn transcriptional regulator contributes to the virulence of Streptococcus pneumoniae. It is thought to be a member of the Mga/AtxA family of global regulators. MgaSpn was shown to activate in vivo the P1623B promoter, which is divergent from the promoter (Pmga) of its own gene. This activation required a 70-bp region (PB activation region) located between both promoters. In this work, we purified an untagged form of the MgaSpn protein, which formed dimers in solution. By gel retardation and footprinting assays, we analysed the binding of MgaSpn to linear double-stranded DNAs. MgaSpn interacted with the PB activation region when it was placed at internal position on the DNA. However, when it was positioned at one DNA end, MgaSpn recognized preferentially the Pmga promoter placed at internal position. In both cases, and on binding to the primary site, MgaSpn spread along the adjacent DNA regions generating multimeric protein–DNA complexes. When both MgaSpn-binding sites were located at internal positions on longer DNAs, electron microscopy experiments demonstrated that the PB activation region was the preferred target. DNA molecules totally or partially covered by MgaSpn were also visualized. Our results suggest that MgaSpn might recognize particular DNA conformations to achieve DNA-binding specificity. PMID:23723245

  12. DELAY-DOPPLER CHANNEL ESTIMATION WITH ALMOST LINEAR COMPLEXITY --BY FISH, GUREVICH, HADANI, SAYEED, AND SCHWARTZ 1 Delay-Doppler Channel Estimation in Almost

    E-print Network

    Sayeed, Akbar M.

    DELAY-DOPPLER CHANNEL ESTIMATION WITH ALMOST LINEAR COMPLEXITY -- BY FISH, GUREVICH, HADANI, SAYEED, Ronny Hadani, Akbar Sayeed, and Oded Schwartz To Solomon Golomb for the occasion of his 80 birthday. Sayeed is with the Department of Electrical and Computer Engi- neering, University of Wisconsin, Madison

  13. DELAY-DOPPLER CHANNEL ESTIMATION WITH ALMOST LINEAR COMPLEXITY --BY FISH, GUREVICH, HADANI, SAYEED, AND SCHWARTZ 1 Delay-Doppler Channel Estimation with Almost

    E-print Network

    Sydney, University of

    DELAY-DOPPLER CHANNEL ESTIMATION WITH ALMOST LINEAR COMPLEXITY -- BY FISH, GUREVICH, HADANI, SAYEED, Ronny Hadani, Akbar Sayeed, and Oded Schwartz To Solomon Golomb for the occasion of his 80 birthday@math.utexas.edu. A. Sayeed is with the Department of Electrical and Computer Engineering, University of Wisconsin

  14. DELAY-DOPPLER CHANNEL ESTIMATION WITH ALMOST LINEAR COMPLEXITY --BY FISH, GUREVICH, HADANI, SAYEED, AND SCHWARTZ 1 Delay-Doppler Channel Estimation in Almost

    E-print Network

    Sayeed, Akbar M.

    DELAY-DOPPLER CHANNEL ESTIMATION WITH ALMOST LINEAR COMPLEXITY -- BY FISH, GUREVICH, HADANI, SAYEED, Ronny Hadani, Akbar Sayeed, and Oded Schwartz To Solomon Golomb for the occasion of his 80 birthday 78712, USA. Email: hadani@math.utexas.edu. A. Sayeed is with the Department of Electrical and Computer

  15. Linearly bridging CO2 in a metal-organic framework.

    PubMed

    Yi, Fei-Yan; Jiang, Hai-Long; Sun, Zhong-Ming

    2015-05-18

    A very rare structurally characterized CO2-coordinated metal-organic framework was synthesized by a solvothermal reaction. The CO2 ligand links two open Zn metal centers in a linear and symmetrical ?(O,O') coordination mode with a C[double bond, length as m-dash]O distance of 1.107(4) Å. The new complex reported here is stable under ambient conditions and may provide a new strategy for CO2 fixation. PMID:25738886

  16. Asymmetric allylic substitution catalyzed by C1-symmetrical complexes of molybdenum: structural requirements of the ligand and the stereochemical course of the reaction.

    PubMed

    Malkov, Andrei V; Gouriou, Laure; Lloyd-Jones, Guy C; Starý, Ivo; Langer, Vratislav; Spoor, Paul; Vinader, Victoria; Kocovský, Pavel

    2006-09-01

    Application of new chiral ligands (R)-(-)-12 a and (S)-(+)-12 c (VALDY), derived from amino acids, to the title reaction, involving cinnamyl (linear) and isocinnamyl (branched) type substrates (4 and 5 --> 6), led to excellent regio- and enantioselectivities (>30:1, < or =98 % ee), showing that ligands with a single chiral center are capable of high asymmetric induction. The structural requirements of the ligand and the mechanism are discussed. The application of single enantiomers of deuterium-labeled substrates (both linear 38 c and branched 37 c) and analysis of the products (41-43) by (2)H{(1)H} NMR spectroscopy in a chiral liquid crystal matrix allowed the stereochemical pathways of the reaction to be distinguished. With ligand (S)-(+)-12 c, the matched enantiomer of branched substrate was found to be (S)-5, which was converted into (R)-6 with very high regio- and stereoselectivity via a process that involves net retention of stereochemistry. The mismatched enantiomer of the branched substrate was found to be (R)-5, which was also converted into (R)-6, that is, with apparent net inversion, but at a lower rate and with lower overall enantioselectivity. This latter feature, which may be termed a "memory effect", reduced the global enantioselectivity in the reaction of the racemic substrate (+/-)-5. The stereochemical pathway of the mismatched manifold has been shown also to be one of net retention, the apparent inversion occurring through equilibration via an Mo-allyl intermediate prior to nucleophilic attack. Incomplete equilibration leads to the memory effect and thus to lower enantioselectivity. Analysis of the mismatched manifold over the course of the reaction revealed that the memory effect is progressively attenuated with the nascent global selectivity increasing substantially as the reaction proceeds. The origin of this effect is suggested to be the depletion of CO sources in the reaction mixture, which attenuates turnover rate and thus facilitates greater equilibrium. The linear substrate was also converted into the branched product with net syn stereochemistry, as shown by isotopic labeling. An analogous process operates in the generation of small quantities of linear product from branched substrate. PMID:16807930

  17. Viscosity in spherically symmetric accretion

    E-print Network

    Arnab K. Ray

    2004-09-27

    The influence of viscosity on the flow behaviour in spherically symmetric accretion, has been studied here. The governing equation chosen has been the Navier-Stokes equation. It has been found that at least for the transonic solution, viscosity acts as a mechanism that detracts from the effectiveness of gravity. This has been conjectured to set up a limiting scale of length for gravity to bring about accretion, and the physical interpretation of such a length-scale has been compared with the conventional understanding of the so-called "accretion radius" for spherically symmetric accretion. For a perturbative presence of viscosity, it has also been pointed out that the critical points for inflows and outflows are not identical, which is a consequence of the fact that under the Navier-Stokes prescription, there is a breakdown of the invariance of the stationary inflow and outflow solutions -- an invariance that holds good under inviscid conditions. For inflows, the critical point gets shifted deeper within the gravitational potential well. Finally, a linear stability analysis of the stationary inflow solutions, under the influence of a perturbation that is in the nature of a standing wave, has indicated that the presence of viscosity induces greater stability in the system, than has been seen for the case of inviscid spherically symmetric inflows.

  18. Condition Number Complexity of an Elementary Algorithm for Computing a Reliable Solution of a Conic Linear System

    Microsoft Academic Search

    Marina Epelman; Robert M. Freund

    1997-01-01

    . A conic linear system is a system of the form (FP d ) Ax = b x 2 CX ; where A : X ! Y is a linear operator between n- and m-dimensional linear spaces X and Y , b 2 Y , and CX X is a closed convex cone. The data for the system is d

  19. Properties of Cationic Pnicogen-Bonded Complexes F4-nHnP(+):N-Base with F-P···N Linear and n = 0-3.

    PubMed

    Del Bene, Janet E; Alkorta, Ibon; Elguero, José

    2015-06-01

    Ab initio MP2/aug'-cc-pVTZ calculations were performed to investigate the pnicogen-bonded complexes F4-nHnP(+):N-base, for n = 0-3, each with a linear or nearly linear F-P···N alignment. The nitrogen bases include the sp(3) bases NH3, NClH2, NFH2, NCl2H, NCl3, NFCl2, NF2H, NF2Cl, and NF3 and the sp bases NCNH2, NCCH3, NP, NCOH, NCCl, NCH, NCF, NCCN, and N2. The binding energies vary between -20 and -180 kJ·mol(-1), while the P-N distances vary from 1.89 to 3.01 Å. In each series of complexes, binding energies decrease exponentially as the P-N distance increases, provided that complexes with sp(3) and sp hybridized bases are treated separately. Different patterns are observed for the change in the binding energies of complexes with a particular base as the number of F atoms in the acid changes. Thus, the particular acid-base pair is a factor in determining the binding energies of these complexes. Three different charge-transfer interactions stabilize these complexes. These arise from the nitrogen lone pair to the ?*P-Fax, ?*P-Feq, and ?*P-Heq orbitals. The dominant single charge-transfer energy in all complexes is Nlp ? ?*P-Fax. However, since there are three Nlp ? ?*P-Feq charge-transfer interactions in complexes with F4P(+) and two in complexes with F3HP(+), the sum of the Nlp ? ?*P-Feq charge-transfer energies is greater than the Nlp ? ?*P-Fax charge-transfer energies in the former complexes, and similar to the Nlp ? ?*P-Fax energies in the latter. The total charge-transfer energies of all complexes decrease exponentially as the P-N distance increases. Coupling constants (1p)J(P-N) across the pnicogen bond vary with the P-N distance, but different patterns are observed for complexes with F4P(+) and complexes of the sp(3) bases with F3HP(+). These initially increase as the P-N distance decreases, reach a maximum, and then decrease with decreasing P-N distance as the P···N bond acquires increased covalent character. For the remaining complexes, (1p)J(P-N) increases with decreasing P-N distance. Complexation increases the P-Fax distance and (1)J(P-Fax) relative to the corresponding isolated ion. (1)J(P-Fax) correlates quadratically with the P-N distance. PMID:26009801

  20. PT-Symmetric Talbot Effects

    E-print Network

    Ramezani, Hamidreza; Kovanis, V; Vitebskiy, I; Kottos, Tsampikos; 10.1103/PhysRevLett.109.033902

    2012-01-01

    We show that complex PT-symmetric photonic lattices can lead to a new class of self-imaging Talbot effects. For this to occur, we find that the input field pattern, has to respect specific periodicities which are dictated by the symmetries of the system. While at the spontaneous PT-symmetry breaking point, the image revivals occur at Talbot lengths governed by the characteristics of the passive lattice, at the exact phase it depends on the gain and loss parameter thus allowing one to control the imaging process.

  1. PT-symmetric optical lattices

    SciTech Connect

    Makris, Konstantinos G.; El-Ganainy, Ramy; Christodoulides, Demetrios N.; Musslimani, Z. H. [College of Optics/CREOL, University of Central Florida, Orlando, Florida 32816 (United States); Department of Mathematics, Florida State University Tallahassee, Florida 32306-4510 (United States)

    2010-06-15

    The basic properties of Floquet-Bloch (FB) modes in parity-time (PT)-symmetric optical lattices are examined in detail. Due to the parity-time symmetry of such complex periodic potentials, the corresponding FB modes are skewed (nonorthogonal) and nonreciprocal. The conjugate pairs of these FB modes are obtained by reflecting both the spatial coordinate and the Bloch momentum number itself. The orthogonality conditions are analytically derived for a single cell, for both a finite and an infinite lattice. Some of the peculiarities associated with the diffraction dynamics in PT lattices such as nonreciprocity, power oscillations, and phase dislocations, are also examined.

  2. On the communication complexity of XOR functions

    E-print Network

    Ashley Montanaro; Tobias Osborne

    2010-02-10

    An XOR function is a function of the form g(x,y) = f(x + y), for some boolean function f on n bits. We study the quantum and classical communication complexity of XOR functions. In the case of exact protocols, we completely characterise one-way communication complexity for all f. We also show that, when f is monotone, g's quantum and classical complexities are quadratically related, and that when f is a linear threshold function, g's quantum complexity is Theta(n). More generally, we make a structural conjecture about the Fourier spectra of boolean functions which, if true, would imply that the quantum and classical exact communication complexities of all XOR functions are asymptotically equivalent. We give two randomised classical protocols for general XOR functions which are efficient for certain functions, and a third protocol for linear threshold functions with high margin. These protocols operate in the symmetric message passing model with shared randomness.

  3. A Pyridine-Based Ligand with Two Hydrazine Functions for Lanthanide Chelation: Remarkable Kinetic Inertness for a Linear, Bishydrated Complex.

    PubMed

    Bonnet, Célia S; Laine, Sophie; Buron, Frédéric; Tircsó, Gyula; Pallier, Agnès; Helm, Lothar; Suzenet, Franck; Tóth, Éva

    2015-06-15

    To study the influence of hydrazine functions in the ligand skeleton, we designed the heptadentate HYD ligand (2,2',2?,2?-(2,2'-(pyridine-2,6-diyl)bis(2-methylhydrazine-2,1,1-triyl)) tetraacetic acid) and compared the thermodynamic, kinetic, and relaxation properties of its Ln(3+) complexes to those of the parent pyridine (Py) analogues without hydrazine (Py = 2,6-pyridinebis(methanamine)-N,N,N',N'-tetraacetic acid). The protonation constants of HYD were determined by pH-potentiometric measurements, and assigned by a combination of UV-visible and NMR spectroscopies. The protonation sequence is rather unusual and illustrates that small structural changes can strongly influence ligand basicity. The first protonation step occurs on the pyridine nitrogen in the basic region, followed by two hydrazine nitrogens and the carboxylate groups at acidic pH. Contrary to Py, HYD self-aggregates through a pH-dependent process (from pH ca. 4). Thermodynamic stability constants have been obtained by pH-potentiometry and UV-visible spectrophotometry for various Ln(3+) and physiological cations (Zn(2+), Ca(2+), Cu(2+)). LnHYD stability constants show the same trend as those of LnDTPA complexes along the Ln(3+) series, with log K = 18.33 for Gd(3+), comparable to the Py analogue. CuHYD has a particularly high stability (log K > 19) preventing its determination from pH-potentiometric measurements. The stability constant of CuPy was also revisited and found to be underestimated in previous studies, highlighting that UV-visible spectrophotometry is often indispensable to obtain reliable stability constants for Cu(2+) chelates. The dissociation of GdL, assessed by studying the Cu(2+)-exchange reaction, occurs mainly via an acid-catalyzed process, with limited contribution from direct Cu(2+) attack. The kinetic inertness of GdHYD is remarkable for a linear bishydrated chelate; the 25-fold increase in the dissociation half-life with respect to the monohydrated commercial contrast agent GdDTPA (t1/2 = 5298 h for GdHYD vs 202 h for GdDTPA) is related to the rigidity of the HYD ligand due to the pyridine and methylated hydrazine functions of the backbone. A combined analysis of variable-temperature (17)O NMR and NMRD data on GdHYD yielded the microscopic parameters influencing relaxation properties. The high relaxivity (r1 = 7.7 mM(-1) s(-1) at 20 MHz, 25 °C) results from the bishydrated character of the complex combined with an optimized water exchange rate (kex(298) = 7.8 × 10(6) s(-1)). The two inner-sphere water molecules are not replaced through interaction with biological cations such as carbonate, citrate, and phosphate as monitored by (1)H relaxivity and luminescence lifetime measurements. PMID:26030671

  4. Creating a Symmetrical Design

    NSDL National Science Digital Library

    National Security Agency Central Security Service

    2009-04-24

    This unit teaches students the meaning of symmetry by having them manipulate a variety of objects. Using this knowledge, they will create a symmetrical design and write an informative paragraph about the quilt design and the importance of symmetry.

  5. Resonances for Symmetric Two-Barrier Potentials

    ERIC Educational Resources Information Center

    Fernandez, Francisco M.

    2011-01-01

    We describe a method for the accurate calculation of bound-state and resonance energies for one-dimensional potentials. We calculate the shape resonances for symmetric two-barrier potentials and compare them with those coming from the Siegert approximation, the complex scaling method and the box-stabilization method. A comparison of the…

  6. Vector fields on $?$-symmetric flag supermanifolds

    E-print Network

    E. G. Vishnyakova

    2015-06-07

    The main result of this paper is the computation of the Lie superalgebras of holomorphic vector fields on the complex $\\Pi$-symmetric flag supermanifolds, introduced by Yu.I.~Manin. We prove that with one exception any vector field is fundamental with respect to the natural action of the Lie superalgebra $\\mathfrak q_n(\\mathbb C)$.

  7. Construction of dynamics and time-ordered exponential for unbounded non-symmetric Hamiltonians

    SciTech Connect

    Futakuchi, Shinichiro; Usui, Kouta [Department of Mathematics, Hokkaido University, 060-0810 Sapporo (Japan)

    2014-06-15

    We prove under certain assumptions that there exists a solution of the Schrödinger or the Heisenberg equation of motion generated by a linear operator H acting in some complex Hilbert space H, which may be unbounded, not symmetric, or not normal. We also prove that, under the same assumptions, there exists a time evolution operator in the interaction picture and that the evolution operator enjoys a useful series expansion formula. This expansion is considered to be one of the mathematically rigorous realizations of so-called “time-ordered exponential,” which is familiar in the physics literature. We apply the general theory to prove the existence of dynamics for the mathematical model of Quantum Electrodynamics quantized in the Lorenz gauge, the interaction Hamiltonian of which is not even symmetric or normal.

  8. Noncommutative spherically symmetric spaces

    SciTech Connect

    Murray, Sean; Govaerts, Jan [Centre for Cosmology, Particle Physics and Phenomenology, Universite catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium); Centre for Cosmology, Particle Physics and Phenomenology, Universite catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium) and International Chair in Mathematical Physics and Applications, University of Abomey-Calavi, 072 B. P. 50, Cotonou (Benin)

    2011-01-15

    We examine some noncommutative spherically symmetric spaces in three space dimensions. A generalization of Snyder's noncommutative (Euclidean) space allows the inclusion of the generator of dilations into the defining algebra of the coordinate and rotation operators. We then construct a spherically symmetric noncommutative Laplacian on this space having the correct limiting spectrum. This is presented via a creation and annihilation operator realization of the algebra, which may lend itself to a truncation of the Hilbert space.

  9. Synthesis, crystal structures and magnetic properties of bis(?-dialkoxo)-bridged linear trinuclear copper(II) complexes with aminoalcohol ligands: a theoretical/experimental magneto-structural study.

    PubMed

    Seppälä, Petri; Colacio, Enrique; Mota, Antonio J; Sillanpää, Reijo

    2012-03-01

    The bis(?-dialkoxo)-bridged trinuclear copper(II) complexes [Cu(3)(ap)(4)(ClO(4))(2)EtOH] (1), [Cu(3)(ap)(4)(NO(3))(2)] (2), [Cu(3)(ap)(4)Br(2)] (3) and [Cu(3)(ae)(4)(NO(3))(2)] (4) (ae = 2-aminoethanolato and ap = 3-aminopropanolato) have been synthesised via self-assembly from chelating aminoalcohol ligands with the corresponding copper(II) salts. The complexes are characterised by single-crystal X-ray diffraction analyses and variable temperature magnetic measurements. The crystal structures of complexes 1-4 consist of slightly bent linear or linear trinuclear [Cu(3)(aa)(4)](2+) (aa = aminoalcoholato) units to which the perchlorate, nitrate or bromide anions are weakly coordinated. The adjacent trinuclear units of 1-4 are connected together by hydrogen bonds and bridging nitrate or bromide anions resulting in the formation of 2D layers. Magnetic studies of 1, 2 and 4 show that J values vary from -379 to +36.0 cm(-1) as the Cu-O-Cu angle (?) and the out-of-plane shift of the carbon atom of the bridging alkoxo group (?) vary from 103.7 to 94.4° and from 0.9 to 35.5°, respectively. Magnetic exchange coupling constants calculated by DFT methods are of the same nature and magnitude as the experimental ones. For complexes 1, 2 and 4, which have complementarity effects between the ? and ? angles (small ? values are associated with large ? values and vice versa), an almost linear relationship between the calculated J values with ? angles could be established, thus supporting that the ? and ? angles are the two key structural factors that determine the magnetic exchange coupling for such a type of compounds. Complex 3 does not obey this linear correlation because of the existence of counter-complementarity effects between these angles (small ? values are associated with small ? values and vice versa). It is of interest that the theoretical calculations for the magnetic exchange interaction between next-nearest neighbours indicate that the usual approximation in experimental studies of neglecting the magnetic coupling between the next-nearest neighbours in linear trinuclear complexes could lead to considerable errors, especially when J(1) and J(2) are of the same order of magnitude as J(3). PMID:22234645

  10. Photodissociation of the linear Ar-I2 van der Waals complex: velocity-map imaging of the I2 fragment.

    PubMed

    Zhang, Yongwei; Vidma, Konstantin; Parker, David H; Loomis, Richard A

    2009-03-14

    Photodissociation of the Ar-I(2) 1:1 linear van der Waals complex is studied over the 490-520 nm region using the velocity-map imaging technique. Molecular iodine, and both the T-shaped and linear Ar-I(2)(X,v(")=0) ground-state complexes absorb strongly in this range, and these transitions access both the bound and dissociative regions of the I(2)(B) state. We measure the angle-speed distribution of vibrationally excited I(2)(B,v(')) state products by resonant 1+1 ionization via the E and f ion-pair states, forming I(2) (+), which is imaged under velocity-mapping conditions. The images show a strong angular anisotropy, which is the same for all excitation energies, spanning from the bound region to above the molecular dissociation limit. The observed angular anisotropy of the I(2) fragments is consistent with a direct dissociation of linear Ar-I(2) complexes promoted to the inner repulsive potential wall of the Ar+I(2)(B,v(')) potential energy surface. PMID:19292529

  11. A Minimally Symmetric Higgs Boson

    E-print Network

    Ian Low

    2015-06-10

    Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized SU(2)xU(1) electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal in all models where the Higgs arises as a pseudo-Nambu-Goldstone boson (PNGB). Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.

  12. Symmetric differential capacitive pressure sensor

    NASA Astrophysics Data System (ADS)

    Peters, Randall D.

    1993-08-01

    Differential capacitive sensors are common to pressure gauges. Previous sensors of the bridge type have utilized only two variable (active) components, resulting in a half-bridge electrical equivalent circuit. There are numerous advantages of a symmetric full bridge, using four active components. The symmetry improves linearity and increases signal to noise ratio, especially when supported by electronics based on synchronous detection. Another advantage of symmetry is invariance to scaling, through immunity to stray capacitance. This feature is especially important in relationship to the current trend toward micro-electro-mechanical systems. A crude, inexpensive, macroscopic prototype of the present design was built with attention to high sensitivity. Constructed with a thin aluminized Mylar diaphragm, this device can readily resolve pressure changes smaller than 10-2 Pa.

  13. A Minimally Symmetric Higgs Boson

    E-print Network

    Ian Low

    2014-12-05

    Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized SU(2)xU(1) electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal in all models where the Higgs arises as a pseudo-Nambu-Goldstone boson (PNGB). Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.

  14. Condition number complexity of an elementary algorithm for computing a reliable solution of a conic linear system

    Microsoft Academic Search

    Marina Epelman; Robert M. Freund

    2000-01-01

    .   A conic linear system is a system of the form¶¶(FP\\u000a d\\u000a \\u000a )Ax=b¶x?C\\u000a \\u000a X\\u000a ,¶¶where A:X?Y is a linear operator between n- and m-dimensional linear spaces X and Y, b?Y, and C\\u000a \\u000a X\\u000a \\u000a ?X is a closed convex cone. The data for the system is d=(A,b). This system is “well-posed” to the extent that (small) changes in the data d=(A,b)

  15. On the Fourier Spectrum of Symmetric Boolean Functions Mihail N. Kolountzakis

    E-print Network

    Kolountzakis, Mihalis

    is to understand the complexity of learning symmetric juntas. A k-junta is a boolean function of n variablesOn the Fourier Spectrum of Symmetric Boolean Functions Mihail N. Kolountzakis Richard J. Lipton is the smallest t such that every symmetric boolean function on k variables (which is not a constant or a parity

  16. On the Fourier Spectrum of Symmetric Boolean Functions # Mihail N. Kolountzakis + Richard J. Lipton # Evangelos Markakis

    E-print Network

    Kolountzakis, Mihalis

    is to understand the complexity of learning symmetric juntas. A k­junta is a boolean function of n variablesOn the Fourier Spectrum of Symmetric Boolean Functions # Mihail N. Kolountzakis + Richard J. Lipton is the smallest t such that every symmetric boolean function on k variables (which is not a constant or a parity

  17. The symmetric method 

    E-print Network

    Strub, James Earl

    1962-01-01

    = T and the proof of' (2) III. C~ PROGRAM OF THE SYMMETRIC METHOD Descri ion The computer program oi' the Symmetric Method is in the form of a FAP subroutine for the IBM 709/7090. This subroutine is compatible with either FORTRAN or FAP calling programs and... includes 2' locations for P snd thus permits an n of 244 if the calling program hss 29, 890 locations available for the array A. Csllin Se uence Be irements A FORTRAN calling program will use the statement CALL SYMINV(ApNpDELTA~INDCTR) where...

  18. Braids, shuffles and symmetrizers

    NASA Astrophysics Data System (ADS)

    Isaev, A. P.; Ogievetsky, O. V.

    2009-07-01

    Multiplicative analogues of the shuffle elements of the braid group rings are introduced; in local representations they give rise to certain graded associative algebras (b-shuffle algebras). For the Hecke and BMW algebras, the (anti)-symmetrizers have simple expressions in terms of the multiplicative shuffles. The (anti)-symmetrizers can be expressed in terms of the highest multiplicative 1-shuffles (for the Hecke and BMW algebras) and in terms of the highest additive 1-shuffles (for the Hecke algebras). The spectra and multiplicities of eigenvalues of the operators of the multiplication by the multiplicative and additive 1-shuffles are examined. Dedicated to the memory of Aleosha Zamolodchikov.

  19. On the optimum bit orders with respect to the state complexity of trellis diagrams for binary linear codes

    NASA Technical Reports Server (NTRS)

    Kasami, Tadao; Takata, Toyoo; Fujiwara, Toru; Lin, Shu

    1993-01-01

    It was shown earlier that for a punctured Reed-Muller (RM) code or a primitive BCH code, which contains a punctured RM code of the same minimum distance as a large subcode, the state complexity of the minimal trellis diagram is much greater than that for an equivalent code obtained by a proper permutation on the bit positions. To find a permutation on the bit positions for a given code that minimizes the state complexity of its minimal trellis diagram is an interesting and challenging problem. This permutation problem is related to the generalized Hamming weight hierarchy of a code, and is shown that for RM codes, the standard binary order of bit positions is optimum at every bit position with respect to the state complexity of a minimal trellis diagram by using a theorem due to Wei. The state complexity of trellis diagram for the extended and permuted (64, 24) BCH code is discussed.

  20. A free-knot spline modeling framework for piecewise linear logistic regression in complex samples with body mass index and mortality as an example

    PubMed Central

    Keith, Scott W.; Allison, David B.

    2014-01-01

    This paper details the design, evaluation, and implementation of a framework for detecting and modeling nonlinearity between a binary outcome and a continuous predictor variable adjusted for covariates in complex samples. The framework provides familiar-looking parameterizations of output in terms of linear slope coefficients and odds ratios. Estimation methods focus on maximum likelihood optimization of piecewise linear free-knot splines formulated as B-splines. Correctly specifying the optimal number and positions of the knots improves the model, but is marked by computational intensity and numerical instability. Our inference methods utilize both parametric and nonparametric bootstrapping. Unlike other nonlinear modeling packages, this framework is designed to incorporate multistage survey sample designs common to nationally representative datasets. We illustrate the approach and evaluate its performance in specifying the correct number of knots under various conditions with an example using body mass index (BMI; kg/m2) and the complex multi-stage sampling design from the Third National Health and Nutrition Examination Survey to simulate binary mortality outcomes data having realistic nonlinear sample-weighted risk associations with BMI. BMI and mortality data provide a particularly apt example and area of application since BMI is commonly recorded in large health surveys with complex designs, often categorized for modeling, and nonlinearly related to mortality. When complex sample design considerations were ignored, our method was generally similar to or more accurate than two common model selection procedures, Schwarz’s Bayesian Information Criterion (BIC) and Akaike’s Information Criterion (AIC), in terms of correctly selecting the correct number of knots. Our approach provided accurate knot selections when complex sampling weights were incorporated, while AIC and BIC were not effective under these conditions. PMID:25610831

  1. Bcl2 inhibits recruitment of Mre11 complex to DNA double-strand breaks in response to high-linear energy transfer radiation

    PubMed Central

    Xie, Maohua; Park, Dongkyoo; You, Shuo; Li, Rui; Owonikoko, Taofeek K.; Wang, Ya; Doetsch, Paul W.; Deng, Xingming

    2015-01-01

    High-linear energy transfer ionizing radiation, derived from high charge (Z) and energy (E) (HZE) particles, induces clustered/complex DNA double-strand breaks (DSBs) that include small DNA fragments, which are not repaired by the non-homologous end-joining (NHEJ) pathway. The homologous recombination (HR) DNA repair pathway plays a major role in repairing DSBs induced by HZE particles. The Mre11 complex (Mre11/Rad50/NBS1)-mediated resection of DSB ends is a required step in preparing for DSB repair via the HR DNA repair pathway. Here we found that expression of Bcl2 results in decreased HR activity and retards the repair of DSBs induced by HZE particles (i.e. 56iron and 28silicon) by inhibiting Mre11 complex activity. Exposure of cells to 56iron or 28silicon promotes Bcl2 to interact with Mre11 via the BH1 and BH4 domains. Purified Bcl2 protein directly suppresses Mre11 complex-mediated DNA resection in vitro. Expression of Bcl2 reduces the ability of Mre11 to bind DNA following exposure of cells to HZE particles. Our findings suggest that, after cellular exposure to HZE particles, Bcl2 may inhibit Mre11 complex-mediated DNA resection leading to suppression of the HR-mediated DSB repair in surviving cells, which may potentially contribute to tumor development. PMID:25567982

  2. Symmetrohedra: Polyhedra from Symmetric

    E-print Network

    Kaplan, Craig S.

    Symmetrohedra: Polyhedra from Symmetric Placement of Regular Polygons Craig S. Kaplan University://www.georgehart.com george@georgehart.com Abstract In the quest for new visually interesting polyhedra with regular faces, we axes of a polyhedral symmetry group. This new technique can be used to generate many existing polyhedra

  3. Self-assembly behavior of a linear-star supramolecular amphiphile based on host-guest complexation.

    PubMed

    Wang, Juan; Wang, Xing; Yang, Fei; Shen, Hong; You, Yezi; Wu, Decheng

    2014-11-01

    A star polymer, ?-cyclodextrin-poly(l-lactide) (?-CD-PLLA), and a linear polymer, azobenzene-poly(ethylene glycol) (Azo-PEG), could self-assemble into a supramolecular amphiphilic copolymer (?-CD-PLLA@Azo-PEG) based on the host-guest interaction between ?-CD and azobenzene moieties. This linear-star supramolecular amphiphilic copolymer further self-assembled into a variety of morphologies, including sphere-like micelle, carambola-like micelle, naan-like micelle, shuttle-like lamellae, tube-like fiber, and random curled-up lamellae, by tuning the length of hydrophilic or hydrophobic chains. The variation of morphology was closely related to the topological structure and block ratio of the supramolecular amphiphiles. These self-assembly structures could disassemble upon an ultraviolet (UV) light irradiation. PMID:25310380

  4. Controlled release of ?-tocopherol, quercetin, and their cyclodextrin inclusion complexes from linear low-density polyethylene (LLDPE) films into a coconut oil model food system.

    PubMed

    Koontz, J L; Moffitt, R D; Marcy, J E; O'Keefe, S F; Duncan, S E; Long, T E

    2010-11-01

    Polymer additive migration into a food product is dependent upon numerous factors including the original concentration of the additive in the polymer, its solubility in the food, its diffusion coefficient in the polymer, its partition coefficient between the polymer and food, temperature, and time. The limited solubility of quercetin in linear low-density polyethylene (LLDPE) did not allow release from the film due to phase segregation of the quercetin in the bulk polymer. Increasing the molecular weight of ?-tocopherol by ?-cyclodextrin inclusion complexation can greatly reduce its diffusion coefficient in LLDPE. Ziegler-Natta and metallocene LLDPE contain different crystalline structure morphologies and diffusion path networking arrangements that allow for differences in additive release rates. Effective controlled-release packaging should combine ?-cyclodextrin complexation of additives and polymer morphology control to target delivery of an optimal antioxidant concentration to achieve prolonged activity, resulting in extended shelf life foods. PMID:20672204

  5. Accelerating simulations of first principle models of complex industrial processes using accurate quasi linear parameter varying models

    Microsoft Academic Search

    Robert Bos; Xavier Bombois; Paul M. J. Van den Hof

    First principles models of complex industrial processes are commonly obtained us- ing finite element or finite difference methods. One of the advantages of these models is that the states in the model have a clear physical interpretation. This makes of them perfect candidates for the monitoring of the states of the system. Unfortunately, the CPU time associated with each evaluation

  6. Complexation of Mercury(II) in Soil Organic Matter: EXAFS Evidence for Linear Two-Coordination with Reduced Sulfur Groups

    Microsoft Academic Search

    Ulf Skyllberg; Paul R. Bloom; Jin Qian; Chung-Min Lin; William F. Bleam

    2006-01-01

    The chemical speciation of inorganic mercury (Hg) is to a great extent controlling biologically mediated processes, such as mercury methylation, in soils, sediments, and surface waters. Of utmost importance are complexation reactions with functional groups of natural organic matter (NOM), indirectly determining concentrations of bioavailable, inorganic Hg species. Two previous extended X-ray absorption fine structure (EXAFS) spectroscopic studies have revealed

  7. Separation of fetal and maternal ECG complexes from a mixed signal using an algorithm based on linear regression

    Microsoft Academic Search

    E. S. G. Genevier; A. C. Deans; M. C. Carter; P. J. Steer

    1995-01-01

    Fetal scalp ECG and Doppler ultrasound are the two methods universally used to derive the fetal heart rate (FHR) for cardiotocography. Other fetal signal sources have not been used successfully because of the complexity of the signal and the need for an additional maternal ECG input. In this paper, we present an algorithm for separating the fetal and maternal ECG

  8. Functional models for catechol dioxygenases: iron(III) complexes of cis-facially coordinating linear 3N ligands.

    PubMed

    Velusamy, Marappan; Mayilmurugan, Ramasamy; Palaniandavar, Mallayan

    2005-05-01

    A series of 1:1 iron(III) complexes of simple and sterically hindered tridentate 3N donor ligands have been synthesized and studied as functional models for catechol dioxygenases. All of them are of the type [FeLCl3], where L is bis(pyrid-2-yl-methyl)amine (L1), N,N-bis(benzimidazol-2-ylmethyl)amine (L2), N-methyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L3), N,N-dimethyl-N'-(pyrid-2-ylmethyl)-ethylenediamine (L4) and N-phenyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L5). They have been characterised by spectral and electrochemical methods. The X-ray crystal structure of the complex [Fe(L4)Cl3] has been successfully determined. The complex crystallizes in the triclinic space group P1 with a = 7.250(6), b = 8.284(3), c = 12.409(4) angstroms, alpha = 80.84(3) degrees, beta = 86.76(6) degrees, gamma = 72.09(7) degrees and Z = 2. It possesses a distorted octahedral geometry in which the L4 ligand is cis-facially coordinated to iron(III) and the chloride ions occupy the remaining coordination sites. The systematic variation in the ligand donor atom type significantly influences the Lewis acidity of the iron(III) center and hence the binding interaction of the complexes with simple and substituted catechols. The spectroscopic and electrochemical properties of the catecholate complexes generated in situ have been investigated. All the complexes catalyze mainly the oxidative intradiol cleavage of 3,5-di-tert-butylcatechol (H2DBC) in the presence of dioxygen, which is unexpected of the cis-facial coordination of the ligands. The rate of intradiol catechol cleavage reaction depends upon the Lewis acidity of iron(III) center and steric demand and hydrogen-bonding functionalities of the ligands. Interestingly, the electron-sink property of N-phenyl substituent in [Fe(L5)Cl3] complex leads to enhancement in rate of cleavage. All these observations provide support to the substrate activation mechanism proposed for intradiol-cleaving enzymes. PMID:15833326

  9. Binary Lattice Vector Quantization with Linear Block Codes and Affine Index Assignments

    Microsoft Academic Search

    András Méhes; Kenneth Zeger

    1998-01-01

    We determine analytic expressions for the perfor- mance of some low-complexity combined source-channel coding systems. The main tool used is the Hadamard transform. In particular, we obtain formulas for the average distortion of binary lattice vector quantization with affine index assignments, linear block channel coding, and a binary-symmetric channel. The distortion formulas are specialized to nonredundant chan- nel codes for

  10. Elimination of matrix effect and simultaneous determination of multi-components in complex systems by matrix coefficient non-linearity multivariate calibration based on single point response signals.

    PubMed

    Zhang, Tai-Ming; Yuan, Bin; Liang, Yi-Zeng; Cao, Juan; Pan, Chun-Xiao; Ying, Bin; Lu, Di-Yi

    2007-05-01

    In order to deal with the matrix effect in the simultaneous determination of multi-components in a complex system, we have developed a novel method named matrix coefficient multivariate calibration method (MCMCM) for simultaneously determining n analytes in complex systems. The calibration models of n analytes, which are based on the experimental data of known samples, are first transformed into n linear equations, and then the equations are solved to obtain matrix calibration coefficients of the analytes in congeneric samples. In this way, the concentrations of n analytes in the unknown sample could be obtained easily and simultaneously by solving another n-variate linear equations with the help of the matrix calibration coefficients obtained-above. The method proposed in this work has been tested by voltammetry and atomic absorption spectrometry (AAS) with satisfactory results. On determining the elements such as Cu, Pb, Cd, Ni, Zn, Fe, Mn, Co, Ca, Mg, etc. in synthetic samples, the relative standard deviations (RSDs) of the results were 0.91 - 4.5%, and the recoveries were 95.8 - 105%. For actual samples, the RSDs and the recoveries were 1.5 - 6.9 and 92.0 - 110%, respectively. PMID:17495405

  11. Zero Knowledge and Soundness Are Symmetric

    Microsoft Academic Search

    Shien Jin Ong; Salil P. Vadhan

    2007-01-01

    We give a complexity-theoretic characterization of the class of problems in NP having zero-knowledge argument systems. This char- acterization is symmetric in its treatment of the zero knowledge and the soundness conditions, and thus we deduce that the class of prob- lems in NP \\\\ coNP having zero-knowledge arguments is closed under complement. Furthermore, we show that a problem in

  12. Static cylindrically symmetric spacetimes

    NASA Astrophysics Data System (ADS)

    Fjällborg, Mikael

    2007-05-01

    We prove the existence of static solutions to the cylindrically symmetric Einstein Vlasov system, and we show that the matter cylinder has finite extension in two of the three spatial dimensions. The same results are also proved for a quite general class of equations of state for perfect fluids coupled to the Einstein equations, extending the class of equations of state considered by Bicak et al (2004 Class. Quantum Grav.21 1583). We also obtain this result for the Vlasov Poisson system.

  13. Generalized linear mixed models for ordered responses in complex multilevel structures: effects beneath the school or college in education

    Microsoft Academic Search

    Antony Fielding; Min Yang

    2005-01-01

    The complexities of educational processes and structure and the need for disentangling effects beneath the level of the school or college are discussed. Ordinal response multilevel crossed random-effects models for educational grades are introduced. Weighted random effects for teacher contributions are then added. Estimation methodology is reviewed. Specially written macros for quasi-likelihood with second-order terms are described. The application discusses

  14. Linear coding of complex sound spectra by discharge rate in neurons of the medial nucleus of the trapezoid body (MNTB) and its inputs.

    PubMed

    Koka, Kanthaiah; Tollin, Daniel J

    2014-01-01

    The interaural level difference (ILD) cue to sound location is first encoded in the lateral superior olive (LSO). ILD sensitivity results because the LSO receives excitatory input from the ipsilateral cochlear nucleus and inhibitory input indirectly from the contralateral cochlear nucleus via glycinergic neurons of the ipsilateral medial nucleus of the trapezoid body (MNTB). It is hypothesized that in order for LSO neurons to encode ILDs, the sound spectra at both ears must be accurately encoded via spike rate by their afferents. This spectral-coding hypothesis has not been directly tested in MNTB, likely because MNTB neurons have been mostly described and studied recently in regards to their abilities to encode temporal aspects of sounds, not spectral. Here, we test the hypothesis that MNTB neurons and their inputs from the cochlear nucleus and auditory nerve code sound spectra via discharge rate. The Random Spectral Shape (RSS) method was used to estimate how the levels of 100-ms duration spectrally stationary stimuli were weighted, both linearly and non-linearly, across a wide band of frequencies. In general, MNTB neurons, and their globular bushy cell inputs, were found to be well-modeled by a linear weighting of spectra demonstrating that the pathways through the MNTB can accurately encode sound spectra including those resulting from the acoustical cues to sound location provided by head-related directional transfer functions (DTFs). Together with the anatomical and biophysical specializations for timing in the MNTB-LSO complex, these mechanisms may allow ILDs to be computed for complex stimuli with rapid spectrotemporally-modulated envelopes such as speech and animal vocalizations and moving sound sources. PMID:25565971

  15. Complex degree of mutual anisotropy of linear birefringence and optical activity of biological tissues in diagnostics of prostate cancer

    NASA Astrophysics Data System (ADS)

    Ushenko, V. A.; Gorsky, M. P.

    2013-08-01

    We present theoretical fundamentals of polarization and correlation analysis of the optical anisotropy of biological tissues. Results of measurements of coordinate distributions of the complex degree of mutual anisotropy (CDMA) that are formed by birefringent structures of the prostate tissue with benign and malignant changes are compared. Magnitudes and ranges of variation of statistical (the firstto fourth-order distribution moments) and correlation (excess of autocorrelation functions) parameters of the coordinate CDMA distributions of histological sections of the prostate postoperative bioptic material are studied. Objective criteria of the diagnostics of the appearance of pathology and of the differentiation of the degree of its severity are determined.

  16. Reversible Switching between Nonquenched and Quenched States in Nanoscale Linear Arrays of Plant Light-Harvesting Antenna Complexes

    PubMed Central

    2014-01-01

    A simple and robust nanolithographic method that allows sub-100 nm chemical patterning on a range of oxide surfaces was developed in order to fabricate nanoarrays of plant light-harvesting LHCII complexes. The site-specific immobilization and the preserved functionality of the LHCII complexes were confirmed by fluorescence emission spectroscopy. Nanopatterned LHCII trimers could be reversibly switched between fluorescent and quenched states by controlling the detergent concentration in the imaging buffer. A 3-fold quenching of the average fluorescence intensity was accompanied by a decrease in the average (amplitude-weighted) fluorescence lifetime from approximately 2.24 ns to approximately 0.4 ns, attributed to the intrinsic ability of LHCII to switch between fluorescent and quenched states upon changes in its conformational state. The nanopatterning methodology was extended by immobilizing a second protein, the enhanced green fluorescent protein (EGFP), onto LHCII-free areas of the chemically patterned surfaces. This very simple surface chemistry, which allows simultaneous selective immobilization and therefore sorting of the two types of protein molecules on the surface, is a key underpinning step toward the integration of LHCII into switchable biohybrid antenna constructs. PMID:24988144

  17. Forecasting transitions in systems with high-dimensional stochastic complex dynamics: a linear stability analysis of the tangled nature model.

    PubMed

    Cairoli, Andrea; Piovani, Duccio; Jensen, Henrik Jeldtoft

    2014-12-31

    We propose a new procedure to monitor and forecast the onset of transitions in high-dimensional complex systems. We describe our procedure by an application to the tangled nature model of evolutionary ecology. The quasistable configurations of the full stochastic dynamics are taken as input for a stability analysis by means of the deterministic mean-field equations. Numerical analysis of the high-dimensional stability matrix allows us to identify unstable directions associated with eigenvalues with a positive real part. The overlap of the instantaneous configuration vector of the full stochastic system with the eigenvectors of the unstable directions of the deterministic mean-field approximation is found to be a good early warning of the transitions occurring intermittently. PMID:25615342

  18. Homogeneous solvation controlled photoreduction of cobalt(III) complexes in aqueous 2-methyl-2-propanol solutions linear solvation energy relationship and cyclic voltammetric analyses.

    PubMed

    Anbalagan, K; Lydia, I Sharmila

    2008-03-01

    The effect of solvent participation on the ligand-to-metal charge transfer (LMCT, L-->Co(III)) reduction of the of Co(III)(en)(2)Br(RC(6)H(4)NH(2))(2+) where R=m-OCH(3), p-F, H, m-CH(3), p-CH(3,)p-OC(2)H(5) and p-OCH(3) were examined in aqueous 2-methyl-2-propanol (Bu(t)OH) solutions. The change in the reduction behavior of Co(III) centre was also examined through cyclic voltammetric studies. The observed reduction in quantum yield due to LMCT excitation can mainly be accounted using linear solvation energy relationship (LSER) comprising model correlation equations. These consist of empirical parameters such as Grunwald-Winstein's solvent ionizing power, Y, Dimroth-Richardt's solvent micro-polarity parameter, E(T)(N), Gutmann's donor number, DN(N), along with Kamlet-Taft's solvatochromic parameters (hydrogen bond acceptor acidity/basicity alpha/beta and solvent dipolarity/polarizability, pi*). The origin of solvent effect is found to be due to microscopic interaction between the solvent donor and the nitrogen-bound hydrogen of the ligand. Cyclic voltammograms show an irreversible reduction of Co(III) in DMF using Glassy Carbon Electrode, GCE, the redox peaks for the aniline complexes appear at -0.20 and 0.525V. Irradiation of the complexes with UV light (lambda=254nm) in binary mixtures produce Co(II)(aq) and the concentration of this species are highly dependent on x(alc) (x(alc)=mole fraction of alcohol). The observed quantum yield (logPhi(Co(II))) is found to be linearly related to mole fraction of organic co-solvent added in the mixture, therefore, logPhi(Co(II))=26.41 x 10(-2) when x(2)=0.0094 and 43.75 x 10(-2) when x(2)=0.076 for a typical complex Co(III)(en)(2)Br(p-OCH(3)C(6)H(4)NH(2))(2+) in aqueous 2-methyl-2-propanol at 300K. Cyclic voltammetry and LSER analyses illustrate the variation of reduction property of Co(III) by the aryl ligand and homogeneous solvation of the excited state of the complex Co(III)(en)(2)Br(RC(6)H(4)NH(2))(2+) in H(2)O/Bu(t)OH mixtures. PMID:17698408

  19. Homogeneous solvation controlled photoreduction of cobalt(III) complexes in aqueous 2-methyl-2-propanol solutions. Linear solvation energy relationship and cyclic voltammetric analyses

    NASA Astrophysics Data System (ADS)

    Anbalagan, K.; Lydia, I. Sharmila

    2008-03-01

    The effect of solvent participation on the ligand-to-metal charge transfer (LMCT, L ? Co III) reduction of the of Co III(en) 2Br(RC 6H 4NH 2) 2+ where R = m-OCH 3, p-F, H, m-CH 3, p-CH 3,p-OC 2H 5 and p-OCH 3 were examined in aqueous 2-methyl-2-propanol (Bu tOH) solutions. The change in the reduction behavior of Co III centre was also examined through cyclic voltammetric studies. The observed reduction in quantum yield due to LMCT excitation can mainly be accounted using linear solvation energy relationship (LSER) comprising model correlation equations. These consist of empirical parameters such as Grunwald-Winstein's solvent ionizing power, Y, Dimroth-Richardt's solvent micro-polarity parameter, ETN, Gutmann's donor number, DN N, along with Kamlet-Taft's solvatochromic parameters (hydrogen bond acceptor acidity/basicity ?/ ? and solvent dipolarity/polarizability, ?*). The origin of solvent effect is found to be due to microscopic interaction between the solvent donor and the nitrogen-bound hydrogen of the ligand. Cyclic voltammograms show an irreversible reduction of Co III in DMF using Glassy Carbon Electrode, GCE, the redox peaks for the aniline complexes appear at -0.20 and 0.525 V. Irradiation of the complexes with UV light ( ? = 254 nm) in binary mixtures produce Co IIaq and the concentration of this species are highly dependent on xalc ( xalc = mole fraction of alcohol). The observed quantum yield (log ?Co(II)) is found to be linearly related to mole fraction of organic co-solvent added in the mixture, therefore, log ?Co(II) = 26.41 × 10 -2 when x2 = 0.0094 and 43.75 × 10 -2 when x2 = 0.076 for a typical complex Co III(en) 2Br( p-OCH 3C 6H 4NH 2) 2+ in aqueous 2-methyl-2-propanol at 300 K. Cyclic voltammetry and LSER analyses illustrate the variation of reduction property of Co(III) by the aryl ligand and homogeneous solvation of the excited state of the complex Co III(en) 2Br(RC 6H 4NH 2) 2+ in H 2O/Bu tOH mixtures.

  20. Symmetry breaking in linearly coupled Korteweg-de Vries systems.

    PubMed

    Espinosa-Cerón, A; Malomed, B A; Fujioka, J; Rodríguez, R F

    2012-09-01

    We consider solitons in a system of linearly coupled Korteweg-de Vries (KdV) equations, which model two-layer settings in various physical media. We demonstrate that traveling symmetric solitons with identical components are stable at velocities lower than a certain threshold value. Above the threshold, which is found exactly, the symmetric modes are unstable against spontaneous symmetry breaking, which gives rise to stable asymmetric solitons. The shape of the asymmetric solitons is found by means of a variational approximation and in the numerical form. Simulations of the evolution of an unstable symmetric soliton sometimes produce its breakup into two different asymmetric modes. Collisions between moving stable solitons, symmetric and asymmetric ones, are studied numerically, featuring noteworthy features. In particular, collisions between asymmetric solitons with identical polarities are always elastic, while in the case of opposite polarities the collision leads to a switch of the polarities of both solitons. Three-soliton collisions are studied too, featuring quite complex interaction scenarios. PMID:23020484

  1. On the complex non-linear interaction between bacteria and redox dynamics in sediments and its effects on water quality

    NASA Astrophysics Data System (ADS)

    Sanchez-Vila, X.; Rubol, S.; Fernandez-Garcia, D.

    2011-12-01

    Despite the fact that the prognoses on the availability of resources related to different climate scenarios have been already formulated, the complex hydrological and biogeochemical reactions taking place in different compartments in natural environmental media are poorly understood, especially regarding the interactions between water bodies, and the reactions taking place at soil-water interfaces. Amongst them, the inter-relationship between hydrology, chemistry and biology has important implications in natural (rivers, lakes) and man-made water facilities (lagoons, artificial recharge pounds, reservoirs, slow infiltration systems, etc). The consequences involve environment, economic, social and health-risk aspects. At the current stage, only limited explanations are available to understand the implications of these relationships on ecosystem services, water quality and water quantity. Therefore, there is an urgent need to seek a full understanding of these physical-biogeochemical processes in water-bodies, sediments and biota and its implications in ecological and health risk. We present a soil column experiment and a mathematical model which aim to study the mutual interplay between water and bacteria activity in porous media, the corresponding dynamics and the feedback on nutrient cycling by using a multidisciplinary approach.

  2. Stability of Reflection Symmetric Collapsing Structures

    E-print Network

    M. Sharif; M. Zaeem Ul Haq Bhatti

    2015-05-25

    In this paper, we explore instability regions of non-static axial reflection symmetric spacetime with anisotropic source in the interior. We impose linear perturbation on the Einstein field equations and dynamical equations to establish the collapse equation. The effects of different physical factors like energy density and anisotropic stresses on the instability regions are studied under Newtonian and post-Newtonian limits. We conclude that stiffness parameter has a significant role in this analysis while the reflection terms increase instability ranges of non-static axial collapse.

  3. Stability of Reflection Symmetric Collapsing Structures

    E-print Network

    Sharif, M

    2015-01-01

    In this paper, we explore instability regions of non-static axial reflection symmetric spacetime with anisotropic source in the interior. We impose linear perturbation on the Einstein field equations and dynamical equations to establish the collapse equation. The effects of different physical factors like energy density and anisotropic stresses on the instability regions are studied under Newtonian and post-Newtonian limits. We conclude that stiffness parameter has a significant role in this analysis while the reflection terms increase instability ranges of non-static axial collapse.

  4. Note on free symmetric rigid body motion

    NASA Astrophysics Data System (ADS)

    Dragovi?, Vladimir; Gaji?, Borislav; Jovanovi?, Božidar

    2015-05-01

    We consider the Euler equations of motion of a free symmetric rigid body around a fixed point, restricted to the invariant subspace given by the zero values of the corresponding linear Noether integrals. In the case of the SO( n - 2)-symmetry, we show that almost all trajectories are periodic and that the motion can be expressed in terms of elliptic functions. In the case of the SO( n - 3)-symmetry, we prove the solvability of the problem by using a recent Kozlov's result on the Euler-Jacobi-Lie theorem.

  5. Support graph preconditioners for sparse linear systems 

    E-print Network

    Gupta, Radhika

    2005-02-17

    Elliptic partial differential equations that are used to model physical phenomena give rise to large sparse linear systems. Such systems can be symmetric positive de?nite and can be solved by the preconditioned conjugate gradients method...

  6. Structure and function of cytochrome c2 in electron transfer complexes with the photosynthetic reaction center of Rhodobacter sphaeroides: optical linear dichroism and EPR.

    PubMed

    Drepper, F; Mathis, P

    1997-02-11

    The photosynthetic reaction center (RC) and its secondary electron donor the water-soluble cytochrome (cyt) c2 from the purple bacterium Rhodobacter sphaeroides have been used in cross-linked and non-cross-linked complexes, oriented in compressed gels or partially dried multilayers, to study the respective orientation of the primary donor P (BChl dimer) and of cyt c2. Three methods were used: (i) Polarized optical absorption spectra at 295 and 10 K were measured and the linear dichroism of the two individual transitions (Qx, Qy), which are nearly degenerate within the alpha-band of reduced cyt c2, was determined. Attribution of the polarization directions to the molecular axes within the heme plane yielded the average cyt orientation in the complexes. (ii) Time-resolved flash absorption measurements using polarized light allowed determination of the orientation of cyt c2 in complexes which differ in their kinetics of electron transfer. (iii) EPR spectroscopy of ferricyt c2 in cross-linked RC-cyt c2 complexes was used to determine the angle between the heme and the membrane plane. The results suggest the following structural properties for the docking of cyt c2 to the RC: (i) In cross-linked complexes, the two cytochromes displaying half-lives of 0.7 and 60 micros for electron transfer to P+ are similarly oriented (difference < 10 degrees). (ii) For cross-linked cyt c2 the heme plane is parallel to the symmetry axis of the RC (0 degrees +/- 10 degrees). Moreover, the Qy transition, which is assumed to be polarized within the ring III-ring I direction of the heme plane, makes an angle of 56 degrees +/- 1 degree with the symmetry axis. (iii) The dichroism spectrum for the fast phase (0.7 micros) for the non-cross-linked cyt c2-RC complex suggests an orientation similar to that of cross-linked cyt c2, but the heme plane is tilted about 20 degrees closer to the membrane. An alternative model is that two or more bound states of cyt c2 with heme plane tilt angles between 0 degrees and 30 degrees allow the fast electron transfer. Zero-length cross-linking of cyt c2 may take place in one of these bound states. These orientations of cyt c2 are compared to different structural models of RC-cyt c2 complexes proposed previously. The relation of the two kinetic phases observed in cross-linked cyt c2 complexes to biphasic kinetics of the mobile reaction partners is discussed with respect to the dynamic electrostatic interactions during the formation of a docking complex and its dissociation. A mechanism is proposed in which a pre-orientation of cyt c2 relative to the membrane plane occurs by interaction of its strong electrostatic dipole with the negative surface charges of the RC. The optimal matching of the oppositely charged surfaces of the two proteins necessitates further rotation of the cyt around its dipole axis. PMID:9063891

  7. General Solutions to Static Plane Symmetric Einstein's Equations

    E-print Network

    Leandro G. Gomes

    2013-08-23

    A general formula for the metric as an explicit function of the generic energy-momentum tensor is given which satisfies static plane symmetric Einstein's equations with cosmological constant.In order to illustrate it, the solutions for the vacuum with cosmological constant, the perfect fluid with a linear equation of state and the electrically charged plane are derived and compared with known results. The general solution with a linear relation among the energy-momentum tensor components is also obtained.

  8. Controller Failure Time Analysis for Symmetric H Control Systems Guisheng ZHAI

    E-print Network

    Antsaklis, Panos

    Controller Failure Time Analysis for Symmetric H Control Systems Guisheng ZHAI Department of Opto a controller failure time analysis problem for a class of symmetric linear time-invariant (LTI) systems properties for the entire system. Our objective is to find conditions concerning controller failure time

  9. 14 CFR 23.331 - Symmetrical flight conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...conservative manner when determining the wing loads and linear inertia loads corresponding to any of the symmetrical flight conditions...due to maneuvering and gusts must be reacted by the angular inertia of the airplane in a rational or conservative manner....

  10. 14 CFR 23.331 - Symmetrical flight conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...conservative manner when determining the wing loads and linear inertia loads corresponding to any of the symmetrical flight conditions...due to maneuvering and gusts must be reacted by the angular inertia of the airplane in a rational or conservative manner....

  11. Mutations in NDUFB11, encoding a complex I component of the mitochondrial respiratory chain, cause microphthalmia with linear skin defects syndrome.

    PubMed

    van Rahden, Vanessa A; Fernandez-Vizarra, Erika; Alawi, Malik; Brand, Kristina; Fellmann, Florence; Horn, Denise; Zeviani, Massimo; Kutsche, Kerstin

    2015-04-01

    Microphthalmia with linear skin defects (MLS) syndrome is an X-linked male-lethal disorder also known as MIDAS (microphthalmia, dermal aplasia, and sclerocornea). Additional clinical features include neurological and cardiac abnormalities. MLS syndrome is genetically heterogeneous given that heterozygous mutations in HCCS or COX7B have been identified in MLS-affected females. Both genes encode proteins involved in the structure and function of complexes III and IV, which form the terminal segment of the mitochondrial respiratory chain (MRC). However, not all individuals with MLS syndrome carry a mutation in either HCCS or COX7B. The majority of MLS-affected females have severe skewing of X chromosome inactivation, suggesting that mutations in HCCS, COX7B, and other as-yet-unidentified X-linked gene(s) cause selective loss of cells in which the mutated X chromosome is active. By applying whole-exome sequencing and filtering for X-chromosomal variants, we identified a de novo nonsense mutation in NDUFB11 (Xp11.23) in one female individual and a heterozygous 1-bp deletion in a second individual, her asymptomatic mother, and an affected aborted fetus of the subject's mother. NDUFB11 encodes one of 30 poorly characterized supernumerary subunits of NADH:ubiquinone oxidoreductase, known as complex I (cI), the first and largest enzyme of the MRC. By shRNA-mediated NDUFB11 knockdown in HeLa cells, we demonstrate that NDUFB11 is essential for cI assembly and activity as well as cell growth and survival. These results demonstrate that X-linked genetic defects leading to the complete inactivation of complex I, III, or IV underlie MLS syndrome. Our data reveal an unexpected role of cI dysfunction in a developmental phenotype, further underscoring the existence of a group of mitochondrial diseases associated with neurocutaneous manifestations. PMID:25772934

  12. ccsd00003900, ON SYMMETRIC SENSITIVITY

    E-print Network

    ccsd­00003900, version 1 ­ 14 Jan 2005 ON SYMMETRIC SENSITIVITY Benoît CADRE and Pierre JACOB UMR, 34095 Montpellier cedex 5, FRANCE Abstract We de#28;ne the concept of symmetric sensitivity with respect sensitive map may diverge from a positive quantity independent of the initial points. We study

  13. Averaging in spherically symmetric cosmology

    SciTech Connect

    Coley, A. A.; Pelavas, N. [Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia (Canada)

    2007-02-15

    The averaging problem in cosmology is of fundamental importance. When applied to study cosmological evolution, the theory of macroscopic gravity (MG) can be regarded as a long-distance modification of general relativity. In the MG approach to the averaging problem in cosmology, the Einstein field equations on cosmological scales are modified by appropriate gravitational correlation terms. We study the averaging problem within the class of spherically symmetric cosmological models. That is, we shall take the microscopic equations and effect the averaging procedure to determine the precise form of the correlation tensor in this case. In particular, by working in volume-preserving coordinates, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. We find that the correlation tensor in a Friedmann-Lemaitre-Robertson-Walker (FLRW) background must be of the form of a spatial curvature. Inhomogeneities and spatial averaging, through this spatial curvature correction term, can have a very significant dynamical effect on the dynamics of the Universe and cosmological observations; in particular, we discuss whether spatial averaging might lead to a more conservative explanation of the observed acceleration of the Universe (without the introduction of exotic dark matter fields). We also find that the correlation tensor for a non-FLRW background can be interpreted as the sum of a spatial curvature and an anisotropic fluid. This may lead to interesting effects of averaging on astrophysical scales. We also discuss the results of averaging an inhomogeneous Lemaitre-Tolman-Bondi solution as well as calculations of linear perturbations (that is, the backreaction) in an FLRW background, which support the main conclusions of the analysis.

  14. The odd association of a C(3h) trisamidinium cation and tosylate anion with a series of linear oxalate-bridged trinuclear heterometallic complexes.

    PubMed

    Maxim, Catalin; Pardo, Emilio; Hosseini, Mir Wais; Ferlay, Sylvie; Train, Cyrille

    2013-04-01

    A series of six isostructural heterometallic trinuclear oxalate-bridged complexes of the formula (TDbenz)(2)(TsO)(2)[M(II)(H(2)O)(2){(?-ox)M(III)(ox)(2)}(2)]·6H(2)O·2CH(3)OH (TDbenz = 1,3,5-tris[2-(1,3-diazolinium)]benzene; TsO = 4-methylbenzenesulfonate; ox = oxalate; M(III) = Fe, M(II) = Mn (1), Fe (2), Co (3); M(III) = Cr, M(II) = Mn (4), Fe (5), Co (6)) have been synthesized from (NH(4))(3)[M(III)(ox)(3)]·3H(2)O, the chloride salts of the divalent metal ions and the tosylate salt of 1,3,5-tris[2-(1,3-diazolinium)]benzene (trisamidinium). Whereas the crystal structures of compounds 2, 3, 4 and 5 have been investigated by single-crystal X-ray diffraction, the structures of 1 and 6 have been checked by X-ray powder diffraction. All six compounds are isostructural and crystallise in the P1 space group. The crystals are composed of discrete linear [M(II)(H(2)O)(2){(?-ox)M(III)(ox)(2)}(2)](4-) trinuclear bimetallic units, trisamidinium and tosylate ions and solvent molecules. The linear trinuclear unit is based on a central trans-diaquametal(II) entity connected to two [M(III)(ox)(3)](3-) (M(III) = Cr(III), Fe(III)) moieties through oxalate bridges. The divalent metal ions, surrounded by six oxygen atoms, adopt a distorted octahedral coordination geometry. The coordination sphere is composed of four oxygen atoms belonging to two oxalate ligands and two trans-coordinated water molecules. One of the oxalate ions is coordinated to the central metal centre whereas the other two oxalate ligands are non-bridging. In the crystal, intermolecular hydrogen bonds involving oxalate ligands, solvent molecules and the counter-ions form a complex 3D network. Variable-temperature magnetic susceptibility measurements indicate an antiferromagnetic interaction between the iron(III) and the metal(II) ions (J = -4.23, -6.73, -8.97 cm(-1) for 1, 2 and 3 respectively) whereas this interaction is ferromagnetic when iron(III) is replaced by chromium(III) (J = +1.21, +2.20, +3.63 cm(-1) for 4, 5 and 6 respectively). Moreover, the cobalt(II) derivatives exhibit high D values (D = 29.3 cm(-1) for and D = 27.4 cm(-1) for 6). PMID:23360960

  15. APPROXIMATING SYMMETRIC POSITIVE SEMIDEFINITE TENSORS OF EVEN ORDER*

    PubMed Central

    BARMPOUTIS, ANGELOS; JEFFREY, HO; VEMURI, BABA C.

    2012-01-01

    Tensors of various orders can be used for modeling physical quantities such as strain and diffusion as well as curvature and other quantities of geometric origin. Depending on the physical properties of the modeled quantity, the estimated tensors are often required to satisfy the positivity constraint, which can be satisfied only with tensors of even order. Although the space P02m of 2mth-order symmetric positive semi-definite tensors is known to be a convex cone, enforcing positivity constraint directly on P02m is usually not straightforward computationally because there is no known analytic description of P02m for m > 1. In this paper, we propose a novel approach for enforcing the positivity constraint on even-order tensors by approximating the cone P02m for the cases 0 < m < 3, and presenting an explicit characterization of the approximation ?2m ? ?2m for m ? 1, using the subset ?2m?P02m of semi-definite tensors that can be written as a sum of squares of tensors of order m. Furthermore, we show that this approximation leads to a non-negative linear least-squares (NNLS) optimization problem with the complexity that equals the number of generators in ?2m. Finally, we experimentally validate the proposed approach and we present an application for computing 2mth-order diffusion tensors from Diffusion Weighted Magnetic Resonance Images. PMID:23285313

  16. Achromatic axially symmetric wave plate.

    PubMed

    Wakayama, Toshitaka; Komaki, Kazuki; Otani, Yukitoshi; Yoshizawa, Toru

    2012-12-31

    An achromatic axially symmetric wave plate (AAS-WP) is proposed that is based on Fresnel reflections. The wave plate does not introduce spatial dispersion. It provides retardation in the wavelength domain with an axially symmetric azimuthal angle. The optical configuration, a numerical simulation, and the optical properties of the AAS-WP are described. It is composed of PMMA. A pair of them is manufactured on a lathe. In the numerical simulation, the achromatic angle is estimated and is used to design the devices. They generate an axially symmetric polarized beam. The birefringence distribution is measured in order to evaluate the AAS-WPs. PMID:23388751

  17. Symmetric M-Theory Backgrounds

    E-print Network

    Figueroa-O'Farrill, José

    2011-01-01

    We classify symmetric backgrounds of eleven-dimensional supergravity up to local isometry. In other words, we classify triples (M,g,F), where (M,g) is an eleven-dimensional lorentzian locally symmetric space and F is an invariant 4-form, satisfying the equations of motion of eleven-dimensional supergravity. The possible (M,g) are given either by (not necessarily nondegenerate) Cahen-Wallach spaces or by products AdS_d x M for 1 < d < 8 and M a not necessarily irreducible riemannian symmetric space of dimension 11-d. In most cases we determine the corresponding F-moduli spaces.

  18. Nonlinear wave dynamics near phase transition in $\\mathcal{PT}$-symmetric localized potentials

    E-print Network

    Nixon, Sean

    2015-01-01

    Nonlinear wave propagation in parity-time ($\\mathcal{PT}$) symmetric localized potentials is investigated analytically near a phase-transition point where a pair of real eigenvalues of the potential coalesce and bifurcate into the complex plane. Necessary conditions for phase transition to occur are derived based on a generalization of the Krein signature. Using multi-scale perturbation analysis, a reduced nonlinear ODE model is derived for the amplitude of localized solutions near phase transition. Above phase transition, this ODE model predicts a family of stable solitons not bifurcating from linear (infinitesimal) modes under a certain sign of nonlinearity. In addition, it predicts periodically-oscillating nonlinear modes away from solitons. Under the opposite sign of nonlinearity, it predicts unbounded growth of solutions. Below phase transition, solution dynamics is predicted as well. All analytical results are compared to direct computations of the full system and good agreement is observed.

  19. Linear electric field mass spectrometry

    DOEpatents

    McComas, D.J.; Nordholt, J.E.

    1992-12-01

    A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.

  20. Zero Knowledge and Soundness are Symmetric Shien Jin Ong and Salil Vadhan

    E-print Network

    Vadhan, Salil

    Zero Knowledge and Soundness are Symmetric Shien Jin Ong and Salil Vadhan School of Engineering,salil}@eecs.harvard.edu Abstract. We give a complexity-theoretic characterization of the class of problems in NP having zero-knowledge argument systems. This char- acterization is symmetric in its treatment of the zero knowledge

  1. SYMMETRIC TENSOR DECOMPOSITION Jerome Brachat

    E-print Network

    Paris-Sud XI, Université de

    for symmetric tensors whose rank did not exceed dimension [10] [11]. Now, it has become possible to estimate not fully exploit symmetries [16], minimize different succes- sive criteria sequentially [17] [18

  2. On Landau Theory and Symmetric Energy Landscapes for Phase Transitions

    E-print Network

    Hormann, Kai

    On Landau Theory and Symmetric Energy Landscapes for Phase Transitions Kai Hormann Department of Informatics Clausthal University of Technology Johannes Zimmer Department of Mathematical Sciences University the global complex energy landscapes of phase transitions. For the sake of clarity and brevity the exposition

  3. Staggered parity-time-symmetric ladders with cubic nonlinearity.

    PubMed

    D'Ambroise, Jennie; Kevrekidis, P G; Malomed, Boris A

    2015-03-01

    We introduce a ladder-shaped chain with each rung carrying a parity-time- (PT-) symmetric gain-loss dimer. The polarity of the dimers is staggered along the chain, meaning alternation of gain-loss and loss-gain rungs. This structure, which can be implemented as an optical waveguide array, is the simplest one which renders the system PT-symmetric in both horizontal and vertical directions. The system is governed by a pair of linearly coupled discrete nonlinear Schrödinger equations with self-focusing or defocusing cubic onsite nonlinearity. Starting from the analytically tractable anticontinuum limit of uncoupled rungs and using the Newton's method for continuation of the solutions with the increase of the inter-rung coupling, we construct families of PT-symmetric discrete solitons and identify their stability regions. Waveforms stemming from a single excited rung and double ones are identified. Dynamics of unstable solitons is investigated too. PMID:25871238

  4. Power Amplifier Linearization Techniques

    E-print Network

    Dawson, Joel

    Power Amplifier Linearization Techniques: An Overview Workshop on RF Circuits for 2.5G and 3G(x))) is a linear function of the input variable x. x (Power amplifier) #12;Technique II estimation. · Depends on having a good power amplifier model. · Complexity: incurs power overhead of a DSP

  5. Symmetric and antisymmetric nonlinear modes supported by dual local gain in lossy lattices

    NASA Astrophysics Data System (ADS)

    Chow, K. W.; Ding, Edwin; Malomed, B. A.; Tang, A. Y. S.

    2014-01-01

    We introduce a discrete lossy system, into which a double "hot spot" (HS) is inserted, i.e., two mutually symmetric sites carrying linear gain and cubic nonlinearity. The system can be implemented as an array of optical or plasmonic waveguides, with a pair of amplified nonlinear cores embedded into it. We focus on the case of self-defocusing nonlinearity and cubic losses acting at the HSs. Symmetric localized modes pinned to the double HS are constructed in an implicit analytical form, which is done separately for the cases of odd and even numbers of intermediate sites between the HSs. In the former case, some stationary solutions feature a W-like shape, with a low peak at the central site, added to tall peaks at the positions of the embedded HSs. The special case of two adjacent HSs is considered too. Stability of the solution families against small perturbations is investigated in a numerical form, which reveals stable and unstable subfamilies. The instability generated by an isolated positive eigenvalue leads to a spontaneous transformation into a co-existing stable antisymmetric mode, while a pair of complex-conjugate eigenvalues gives rise to persistent breathers. This article is a contribution to the volume dedicated to Professor Helmut Brand on the occasion of his 60th birhday.

  6. The generalized sidelobe canceller based on quaternion widely linear processing.

    PubMed

    Tao, Jian-wu; Chang, Wen-xiu

    2014-01-01

    We investigate the problem of quaternion beamforming based on widely linear processing. First, a quaternion model of linear symmetric array with two-component electromagnetic (EM) vector sensors is presented. Based on array's quaternion model, we propose the general expression of a quaternion semiwidely linear (QSWL) beamformer. Unlike the complex widely linear beamformer, the QSWL beamformer is based on the simultaneous operation on the quaternion vector, which is composed of two jointly proper complex vectors, and its involution counterpart. Second, we propose a useful implementation of QSWL beamformer, that is, QSWL generalized sidelobe canceller (GSC), and derive the simple expressions of the weight vectors. The QSWL GSC consists of two-stage beamformers. By designing the weight vectors of two-stage beamformers, the interference is completely canceled in the output of QSWL GSC and the desired signal is not distorted. We derive the array's gain expression and analyze the performance of the QSWL GSC in the presence of one type of interference. The advantage of QSWL GSC is that the main beam can always point to the desired signal's direction and the robustness to DOA mismatch is improved. Finally, simulations are used to verify the performance of the proposed QSWL GSC. PMID:24955425

  7. The Generalized Sidelobe Canceller Based on Quaternion Widely Linear Processing

    PubMed Central

    Tao, Jian-wu; Chang, Wen-xiu

    2014-01-01

    We investigate the problem of quaternion beamforming based on widely linear processing. First, a quaternion model of linear symmetric array with two-component electromagnetic (EM) vector sensors is presented. Based on array's quaternion model, we propose the general expression of a quaternion semiwidely linear (QSWL) beamformer. Unlike the complex widely linear beamformer, the QSWL beamformer is based on the simultaneous operation on the quaternion vector, which is composed of two jointly proper complex vectors, and its involution counterpart. Second, we propose a useful implementation of QSWL beamformer, that is, QSWL generalized sidelobe canceller (GSC), and derive the simple expressions of the weight vectors. The QSWL GSC consists of two-stage beamformers. By designing the weight vectors of two-stage beamformers, the interference is completely canceled in the output of QSWL GSC and the desired signal is not distorted. We derive the array's gain expression and analyze the performance of the QSWL GSC in the presence of one type of interference. The advantage of QSWL GSC is that the main beam can always point to the desired signal's direction and the robustness to DOA mismatch is improved. Finally, simulations are used to verify the performance of the proposed QSWL GSC. PMID:24955425

  8. Integrable deformations of strings on symmetric spaces

    NASA Astrophysics Data System (ADS)

    Hollowood, Timothy J.; Miramontes, J. Luis; Schmidtt, David M.

    2014-11-01

    A general class of deformations of integrable sigma-models with symmetric space F/G target-spaces are found. These deformations involve defining the non-abelian T dual of the sigma-model and then replacing the coupling of the Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original sigma-model is obtained in the limit of large level. The resulting deformed theories are shown to preserve both integrability and the equations-of-motion, but involve a deformation of the symplectic structure. It is shown that this deformed symplectic structure involves a linear combination of the original Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket which we show can be re-expressed as two decoupled F current algebras. It is then shown that the deformation can be incorporated into the classical model of strings on via a generalization of the Pohlmeyer reduction. In this case, in the limit of large sigma-model coupling it is shown that the theory becomes the relativistic symmetric space sine-Gordon theory. These results point to the existence of a deformation of this kind for the full Green-Schwarz superstring on AdS5 × S 5.

  9. Transformations between symmetric sets of quantum states

    E-print Network

    Vedran Dunjko; Erika Andersson

    2012-06-22

    We investigate probabilistic transformations of quantum states from a `source' set to a `target' set of states. Such transforms have many applications. They can be used for tasks which include state-dependent cloning or quantum state discrimination, and as interfaces between systems whose information encodings are not related by a unitary transform, such as continuous-variable systems and finite-dimensional systems. In a probabilistic transform, information may be lost or leaked, and we explain the concepts of leak and redundancy. Following this, we show how the analysis of probabilistic transforms significantly simplifies for symmetric source and target sets of states. In particular, we give a simple linear program which solves the task of finding optimal transforms, and a method of characterizing the introduced leak and redundancy in information-theoretic terms. Using the developed techniques, we analyse a class of transforms which convert coherent states with information encoded in their relative phase to symmetric qubit states. Each of these sets of states on their own appears in many well studied quantum information protocols. Finally, we suggest an asymptotic realization based on quantum scissors.

  10. Bunch-Kaufman factorization for real symmetric indefinite banded matrices

    NASA Technical Reports Server (NTRS)

    Jones, Mark T.; Patrick, Merrell L.

    1989-01-01

    The Bunch-Kaufman algorithm for factoring symmetric indefinite matrices was rejected for banded matrices because it destroys the banded structure of the matrix. Herein, it is shown that for a subclass of real symmetric matrices which arise in solving the generalized eigenvalue problem using Lanczos's method, the Bunch-Kaufman algorithm does not result in major destruction of the bandwidth. Space time complexities of the algorithm are given and used to show that the Bunch-Kaufman algorithm is a significant improvement over LU factorization.

  11. Universal symmetric cloning: No-signalling and nonlinear quantum mechanics

    E-print Network

    Gedik, Z

    2012-01-01

    We present a pseudo-spin representation for universal symmetric 1-to-M cloning of qubits, including both linear and nonlinear evolutions. We derive a set of equations to be satisfied by the cloning transformation under the no-signalling condition, and find an expression for the fidelity. We further introduce the linearity constraint, and obtain the unique universal symmetric quantum cloning machine for "an arbitrary" fidelity. No-signalling condition alone leads to fidelities higher than those of the quantum machines, and the maximum value converges to 3/4 rather than the optimal quantum limit of 2/3. We introduce the "prime cloners" whose fidelities have multiplicative property and show that the infinite copy limit of the prime cloners is 1/2.

  12. Matroid matching via mixed skew--symmetric matrices James F. Geelen 1 and Satoru Iwata 2

    E-print Network

    Yamamoto, Hirosuke

    Matroid matching via mixed skew--symmetric matrices James F. Geelen 1 and Satoru Iwata 2 1 generalization of the matching problem contains the linear matroid matching problem and, more generally, the linear delta--matroid parity problem. We present a tight upper bound on the rank of T +K by decomposing

  13. The Theory of Symmetrical Gravity Waves of Finite Amplitude. I

    Microsoft Academic Search

    T. V. Davies

    1951-01-01

    The two-dimensional problem of symmetric finite amplitude gravity waves in an incompressible fluid of infinite depth is treated by a method which first involves satisfying a non-linear boundary condition exactly. The higher approximations are obtained by the method of small parameters. The breaking-wave conditions are discussed and expressions are given for the free-surface equation, the kinetic and the potential energies

  14. Existence of symmetric central configurations

    NASA Astrophysics Data System (ADS)

    Montaldi, James

    2015-06-01

    Central configurations have been of great interest over many years, with the earliest examples due to Euler and Lagrange. There are numerous results in the literature demonstrating the existence of central configurations with specific symmetry properties, using slightly different techniques in each. The aim here is to describe a uniform approach by adapting to the symmetric case the well-known variational argument showing the existence of central configurations. The principal conclusion is that there is a central configuration for every possible symmetry type, and for any symmetric choice of masses. Finally the same argument is applied to the class of balanced configurations introduced by Albouy and Chenciner.

  15. Looking for symmetric Bell inequalities

    NASA Astrophysics Data System (ADS)

    Bancal, Jean-Daniel; Gisin, Nicolas; Pironio, Stefano

    2010-09-01

    Finding all Bell inequalities for a given number of parties, measurement settings and measurement outcomes is in general a computationally hard task. We show that all Bell inequalities which are symmetric under the exchange of parties can be found by examining a symmetrized polytope which is simpler than the full Bell polytope. As an illustration of our method, we generate 238 885 new Bell inequalities and 1085 new Svetlichny inequalities. We find, in particular, facet inequalities for Bell experiments involving two parties and two measurement settings that are not of the Collins-Gisin-Linden-Massar-Popescu type.

  16. Nuclear physics with spherically symmetric supernova models

    E-print Network

    M. Liebendoerfer; T. Fischer; C. Fröhlich; F. -K. Thielemann; S. Whitehouse

    2007-08-31

    Few years ago, Boltzmann neutrino transport led to a new and reliable generation of spherically symmetric models of stellar core collapse and postbounce evolution. After the failure to prove the principles of the supernova explosion mechanism, these sophisticated models continue to illuminate the close interaction between high-density matter under extreme conditions and the transport of leptons and energy in general relativistically curved space-time. We emphasize that very different input physics is likely to be relevant for the different evolutionary phases, e.g. nuclear structure for weak rates in collapse, the equation of state of bulk nuclear matter during bounce, multidimensional plasma dynamics in the postbounce evolution, and neutrino cross sections in the explosive nucleosynthesis. We illustrate the complexity of the dynamics using preliminary 3D MHD high-resolution simulations based on parameterized deleptonization. With established spherically symmetric models we show that typical features of the different phases are reflected in the predicted neutrino signal and that a consistent neutrino flux leads to electron fractions larger than 0.5 in neutrino-driven supernova ejecta.

  17. Ordinary versus PT-symmetric ?³ quantum field theory

    DOE PAGESBeta

    Bender, Carl M.; Branchina, Vincenzo; Messina, Emanuele

    2012-04-01

    A quantum-mechanical theory is PT-symmetric if it is described by a Hamiltonian that commutes with PT, where the operator P performs space reflection and the operator T performs time reversal. A PT-symmetric Hamiltonian often has a parametric region of unbroken PT symmetry in which the energy eigenvalues are all real. There may also be a region of broken PT symmetry in which some of the eigenvalues are complex. These regions are separated by a phase transition that has been repeatedly observed in laboratory experiments. This paper focuses on the properties of a PT-symmetric ig?³ quantum field theory. This quantum fieldmore »theory is the analog of the PT-symmetric quantum-mechanical theory described by the Hamiltonian H=p²+ix³, whose eigenvalues have been rigorously shown to be all real. This paper compares the renormalization group properties of a conventional Hermitian g?³ quantum field theory with those of the PT-symmetric ig?³ quantum field theory. It is shown that while the conventional g?³ theory in d=6 dimensions is asymptotically free, the ig?³ theory is like a g?? theory in d=4 dimensions; it is energetically stable, perturbatively renormalizable, and trivial.« less

  18. Ordinary versus PT-symmetric ?³ quantum field theory

    DOE PAGESBeta

    Bender, Carl M.; Branchina, Vincenzo; Messina, Emanuele

    2012-04-01

    A quantum-mechanical theory is PT-symmetric if it is described by a Hamiltonian that commutes with PT, where the operator P performs space reflection and the operator T performs time reversal. A PT-symmetric Hamiltonian often has a parametric region of unbroken PT symmetry in which the energy eigenvalues are all real. There may also be a region of broken PT symmetry in which some of the eigenvalues are complex. These regions are separated by a phase transition that has been repeatedly observed in laboratory experiments. This paper focuses on the properties of a PT-symmetric ig?³ quantum field theory. This quantum field theory is the analog of the PT-symmetric quantum-mechanical theory described by the Hamiltonian H=p²+ix³, whose eigenvalues have been rigorously shown to be all real. This paper compares the renormalization group properties of a conventional Hermitian g?³ quantum field theory with those of the PT-symmetric ig?³ quantum field theory. It is shown that while the conventional g?³ theory in d=6 dimensions is asymptotically free, the ig?³ theory is like a g?? theory in d=4 dimensions; it is energetically stable, perturbatively renormalizable, and trivial.

  19. Multidimensional linear distinguishing attacks and Boolean functions

    Microsoft Academic Search

    Miia Hermelin; Kaisa Nyberg

    Linear cryptanalysis and linear approximation methods in general are among the most important cryptanalysis methods of symmetric\\u000a ciphers and their components. Recently, these methods have been extended to efficiently exploit multiple linear approximations\\u000a simultaneously. It is known that high nonlinearity of Boolean functions and S-boxes is a desirable property and that the bent\\u000a functions offer the strongest resistance against cryptanalysis

  20. Experimental demonstration of optimal universal asymmetric quantum cloning of polarization states of single photons by partial symmetrization

    E-print Network

    Dusek, Miloslav

    Experimental demonstration of optimal universal asymmetric quantum cloning of polarization states asymmetric 12 quantum cloning machine for qubits encoded into polarization states of single photons. Our linear-optical machine performs asymmetric cloning by partially symmetrizing the input polarization state

  1. Bumblebee preference for symmetrical flowers.

    PubMed

    Møller, A P

    1995-03-14

    Fluctuating asymmetry, which represents small random deviations from otherwise bilateral symmetry, is a measure of the phenotypic quality of individuals indicating the ability of controlled development under given environmental and genetic conditions. I tested whether floral symmetry reliably reflects phenotypic quality measured in terms of pollinator rewards and whether pollinators respond to floral symmetry in a series of observations and experiments on Epilobium angustifolium (Onagraceae). Lower petal asymmetry was negatively related to mean lower petal length, whereas asymmetry in leaf width was positively related to mean leaf width. Flowers visited by bumblebees were larger and more symmetrical than the nearest neighboring flower. This relationship between pollinator preference for large and symmetrical flowers was demonstrated to be causal in experiments in which the lower petals were manipulated symmetrically or asymmetrically. Nectar production was larger in symmetrical flowers, and this may explain the bumblebee preference for flower symmetry. Floral symmetry therefore reliably reflects nectar production and hence enhances pollen transport. Extensive embryo abortion has been documented in E. angustifolium and other outcrossing plant species. Floral fluctuating asymmetry, which reflects general developmental homeostasis, may explain such developmental selection in these plants. PMID:11607519

  2. On Symmetrical Multilevel Diversity Coding

    Microsoft Academic Search

    Raymond W. Yeung; Zhen Zhang

    1999-01-01

    Symmetrical multilevel diversity coding with independent data streams has been studied by Roche et al. (1992), and the admissible coding rate region was determined for the case of three levels. In particular, it was shown that coding by superposition is optimal, which means that optimality can be achieved by very simple coding. However, it is very difficult to generalize their

  3. A note on sampling and parameter estimation in linear stochastic systems

    E-print Network

    Duncan, Tyrone E.; Mandl, P.; Pasik-Duncan, Bozenna

    1999-11-01

    or antisymmetric frequency response,? IEEE Trans. Circuits Syst., vol. 36, pp. 968?979, 1989. [2] S. C. Pei and J. J. Shyu, ?Fast design of 2-D linear-phase complex FIR digital filters by analytical least squares methods,? IEEE Trans. Signal Processing, vol. 44, pp...2120 IEEE TRANSACTIONS ON AUTOMATIC CONTROL, VOL. 44, NO. 11, NOVEMBER 1999 REFERENCES [1] M. O. Ahmad and J. D. Wang, ?An analytical least square solution to the design problem of two-dimensional FIR filters with quadrantally symmetric...

  4. On Some Analogues to Linear Combinations of Order Statistics in the Linear Model

    Microsoft Academic Search

    P. J. Bickel

    1973-01-01

    We consider the general linear model with independent symmetric errors. In this context we propose and examine the large sample behavior of some estimates of the regression parameters. For the location model these statistics are linear combinations of order statistics. In general they depend on a preliminary estimate and the ordered residuals based on it. The asymptotic efficiency of these

  5. Skyrmions and vector mesons: a symmetric approach

    SciTech Connect

    Caldi, D.G.

    1984-01-01

    We propose an extension of the effective, low-energy chiral Lagrangian known as the Skyrme model, to one formulated by a non-linear sigma model generalized to include vector mesons in a symmetric way. The model is based on chiral SU(6) x SU(6) symmetry spontaneously broken to static SU(6). The rho and other vector mesons are dormant Goldstone bosons since they are in the same SU(6) multiplet as the pion and other pseudoscalars. Hence the manifold of our generalized non-linear sigma model is the coset space (SU(6) x SU(6))/Su(6). Relativistic effects, via a spin-dependent mass term, break the static SU(6) and give the vectors a mass. The model can then be fully relativistic and covariant. The lowest-lying Skyrmion in this model is the whole baryonic 56-plet, which splits into the octet and decuplet in the presence of relativistic SU(6)-breaking. Due to the built-in SU(6) and the presence of vector mesons, the model is expected to have better phenomenological results, as well as providing a conceptually more unified picture of mesons and baryons. 29 references.

  6. Replication of avocado sunblotch viroid: evidence for a symmetric pathway with two rolling circles and hammerhead ribozyme processing.

    PubMed

    Daròs, J A; Marcos, J F; Hernández, C; Flores, R

    1994-12-20

    The structure of a series of RNAs extracted from avocado infected by the 247-nt avocado sunblotch viroid (ASBVd) was investigated. The identification of multistranded complexes containing circular ASBVd RNAs of (+) and (-) polarity suggests that replication of ASBVd proceeds through a symmetric pathway with two rolling circles where these two circular RNAs are the templates. This is in contrast to the replication of potato spindle tuber viroid and probably of most of its related viroids, which proceeds via an asymmetric pathway where circular (+)-strand and linear multimeric (-)-strand RNAs are the two templates. Linear (+) and (-) ASBVd RNAs of subgenomic length (137 nt and about 148 nt, respectively) and one linear (+)-strand ASBVd RNA of supragenomic length (383-384 nt) were also found in viroid-infected tissue. The two linear (+)-strand RNAs have the same 5'- and 3'-terminal sequences, with the supragenomic species being a fusion product of the monomeric and subgenomic (+)-strand ASBVd RNAs. The 3' termini of these two (+)-strand molecules, which at least in the subgenomic RNA has an extra nontemplate cytidylate residue, could represent sites of either premature termination of the (+)-strands or specific initiation of the (-)-strands. The 5' termini of sub- and supragenomic (+)-strand and the 5' terminus of the subgenomic (-)-strand ASBVd RNA are identical to those produced in the in vitro self-cleavage reactions of (+) and (-) dimeric ASBVd RNAs, respectively. These observations strongly suggest that the hammerhead structures which mediate the in vitro self-cleavage reactions are also operative in vivo. PMID:7809126

  7. Duality in linearized gravity

    E-print Network

    Marc Henneaux; Claudio Teitelboim

    2005-01-06

    We show that duality transformations of linearized gravity in four dimensions, i.e., rotations of the linearized Riemann tensor and its dual into each other, can be extended to the dynamical fields of the theory so as to be symmetries of the action and not just symmetries of the equations of motion. Our approach relies on the introduction of two "superpotentials", one for the spatial components of the spin-2 field and the other for their canonically conjugate momenta. These superpotentials are two-index, symmetric tensors. They can be taken to be the basic dynamical fields and appear locally in the action. They are simply rotated into each other under duality. In terms of the superpotentials, the canonical generator of duality rotations is found to have a Chern-Simons like structure, as in the Maxwell case.

  8. On the linear stability of solitons and hairy black holes with a negative cosmological constant: the odd-parity sector

    E-print Network

    O. Sarbach; E. Winstanley

    2001-02-08

    Using a recently developed perturbation formalism based on curvature quantities, we investigate the linear stability of black holes and solitons with Yang-Mills hair and a negative cosmological constant. We show that those solutions which have no linear instabilities under odd- and even- parity spherically symmetric perturbations remain stable under odd-parity, linear, non-spherically symmetric perturbations.

  9. Introduction to Modern Cryptography Symmetric Encryption

    E-print Network

    Beimel, Amos

    Introduction to Modern Cryptography Benny Chor Symmetric Encryption: Stream & Block Ciphers Lecture of such G cannot be truly random! Introduction to Modern Cryptography Benny Chor Symmetric Encryption Symmetric Encryption: Stream & Block Ciphers #12;PRGs and OW Functions · Notice that if P=NP then neither

  10. Drawing Trees Symmetrically in Three Dimensions ?

    E-print Network

    Hong,Seokhee

    Drawing Trees Symmetrically in Three Dimensions ? Seok-Hee Hong and Peter Eades School. Symmetric graph drawing enables a clear understanding of the structure of the graph. Previous work on symmetric graph drawing has focused on two dimensions. Symmetry in three dimensions is much richer than

  11. Symmetric Walking Control: Invariance and Global Stability

    Microsoft Academic Search

    Sang-Ho Hyon; Takashi Emura

    2005-01-01

    This paper first presents a novel control strategy for periodic motion control based on a Hamiltonian system. Ac- cording to the strategy, hybrid symmetric orbits (ideal walking gaits) are explored using reversal symmetry of the Hamiltonian system. Then, an invariance controller, a Symmetric Walking Controller, is derived systematically to distribute the symmetric orbits densely throughout the entire phase space. Finally,

  12. Differential complexes and exterior calculus

    E-print Network

    Jenny Harrison

    2006-06-07

    In this paper we present a new theory of calculus over $k$-dimensional domains in a smooth $n$-manifold, unifying the discrete, exterior, and continuum theories. The calculus begins at a single point and is extended to chains of finitely many points by linearity, or superposition. It converges to the smooth continuum with respect to a norm on the space of ``pointed chains,'' culminating in the chainlet complex. Through this complex, we discover a broad theory of coordinate free, multivector analysis in smooth manifolds for which both the classical Newtonian calculus and the Cartan exterior calculus become special cases. The chainlet operators, products and integrals apply to both symmetric and antisymmetric tensor cochains. As corollaries, we obtain the full calculus on Euclidean space, cell complexes, bilayer structures (e.g., soap films) and nonsmooth domains, with equal ease. The power comes from the recently discovered prederivative and preintegral that are antecedent to the Newtonian theory. These lead to new models for the continuum of space and time, and permit analysis of domains that may not be locally Euclidean, or locally connected, or with locally finite mass.

  13. Inflation in a Symmetric Vacuum

    E-print Network

    Kevin Cahill

    2007-05-23

    If in a finite universe, the tree-level vacuum is a symmetric superposition of coherent states, in each of which the inflaton field assumes a different, energy-minimizing mean value (vev), then the resulting energy is positive and decreases exponentially as the volume of the universe increases. This effect can drive inflation when that volume is small and explain part of dark energy when it is big, but the effect is exceedingly tiny except at very early times.

  14. Diagram spaces and symmetric spectra

    Microsoft Academic Search

    Steffen Sagave; Christian Schlichtkrull

    2011-01-01

    We present a general homotopical analysis of structured diagram spaces and discuss the relation to symmetric spectra. The main motivating examples are the I-spaces, which are diagrams indexed by finite sets and injections, and J-spaces, which are diagrams indexed by the Grayson-Quillen construction on the category of finite sets and bijections. We show that the category of I-spaces provides a

  15. Symmetric informationally complete quantum measurements

    Microsoft Academic Search

    Joseph M. Renes; Robin Blume-Kohout; A. J. Scott; Carlton M. Caves

    2004-01-01

    We consider the existence in arbitrary finite dimensions d of a positive operator valued measure (POVM) comprised of d2 rank-one operators all of whose operator inner products are equal. Such a set is called a “symmetric, informationally complete” POVM (SIC–POVM) and is equivalent to a set of d2 equiangular lines in Cd. SIC–POVMs are relevant for quantum state tomography, quantum

  16. Greedy algorithm and symmetric matroids

    Microsoft Academic Search

    André Bouchet

    1987-01-01

    Symmetric matroids are set systems which are obtained, in some sense, by a weakening of the structure of a matroid. These\\u000a set systems are characterized by a greedy algorithm and they are suitable for dealing with autodual properties of matroids.\\u000a Applications are given to the eulerian tours of 4-regular graphs and the theory ofg-matroids.

  17. Symmetrization, quantum images and measurement

    E-print Network

    Fariel Shafee

    2005-07-11

    We argue that symmetrization of an incoming microstate with similar states in a sea of microstates contained in a macroscopic detector can produce an effective image, which does not contradict the no-cloning theorem, and such a combinatorial set can then be used with first passage random walk interactions suggested in an earlier work to give the right quantum mechanical weight for measured eigenvalues.

  18. Symmetry breaking of solitons in two-dimensional complex potentials.

    PubMed

    Yang, Jianke

    2015-02-01

    Symmetry breaking is reported for continuous families of solitons in the nonlinear Schrödinger equation with a two-dimensional complex potential. This symmetry breaking is forbidden in generic complex potentials. However, for a special class of partially parity-time-symmetric potentials, it is allowed. At the bifurcation point, two branches of asymmetric solitons bifurcate out from the base branch of symmetry-unbroken solitons. Stability of these solitons near the bifurcation point are also studied, and two novel properties for the bifurcated asymmetric solitons are revealed. One is that at the bifurcation point, zero and simple imaginary linear-stability eigenvalues of asymmetric solitons can move directly into the complex plane and create oscillatory instability. The other is that the two bifurcated asymmetric solitons, even though having identical powers and being related to each other by spatial mirror reflection, can possess different types of unstable eigenvalues and thus exhibit nonreciprocal nonlinear evolutions under random-noise perturbations. PMID:25768620

  19. The first near-linear bis(amide) f-block complex: a blueprint for a high temperature single molecule magnet.

    PubMed

    Chilton, Nicholas F; Goodwin, Conrad A P; Mills, David P; Winpenny, Richard E P

    2015-01-01

    We report the first near-linear bis(amide) 4f-block compound and show that this novel structure, if implemented with dysprosium(III), would have unprecedented single molecule magnet (SMM) properties with an energy barrier, Ueff, for reorientation of magnetization of 1800 cm(-1). PMID:25384179

  20. Accuracy assessment of the linear Poisson-Boltzmann equation and reparametrization of the OBC generalized Born model for nucleic acids and nucleic acid-protein complexes.

    PubMed

    Fogolari, Federico; Corazza, Alessandra; Esposito, Gennaro

    2015-04-01

    The generalized Born model in the Onufriev, Bashford, and Case (Onufriev et al., Proteins: Struct Funct Genet 2004, 55, 383) implementation has emerged as one of the best compromises between accuracy and speed of computation. For simulations of nucleic acids, however, a number of issues should be addressed: (1) the generalized Born model is based on a linear model and the linearization of the reference Poisson-Boltmann equation may be questioned for highly charged systems as nucleic acids; (2) although much attention has been given to potentials, solvation forces could be much less sensitive to linearization than the potentials; and (3) the accuracy of the Onufriev-Bashford-Case (OBC) model for nucleic acids depends on fine tuning of parameters. Here, we show that the linearization of the Poisson Boltzmann equation has mild effects on computed forces, and that with optimal choice of the OBC model parameters, solvation forces, essential for molecular dynamics simulations, agree well with those computed using the reference Poisson-Boltzmann model. PMID:25581160

  1. How can an agent-based modelling approach help to understand dynamic vulnerability leading to humanitarian crises in complex, non-linear systems?

    Microsoft Academic Search

    Cilli Sobiech

    The paper for the summer academy outlines the conceptual framework and methodological approach for the development of a multi-agent model to achieve an integrative view on the dynamic aspects of social vulnerability. Agent-based models have been introduced to disaster management as an approach which goes beyond structuralistic analysis and linear models. To date they have mainly been used for the

  2. Magnetic Behaviour of the Ferrimagnetic (1B\\/2,5\\/2,1\\/2) Linear Trimer in Complexes of Mn(hfac)2 with Bis and Trisnitroxide Radicals

    Microsoft Academic Search

    A. S. Markosyan; H. Iwamura; K. Inoue

    1999-01-01

    Characterisation and magnetic properties of new metal-radical complexes with bivalent Mn having a general formula {[Mn(hfac)2]m(R)n} are given. In these complexes, the aminoxyl radicals have magnetic, triplet or quartet, ground state and form with Mn heterospin structures. They show 1D, 2D and 3D behaviour depending on the crystal structure, chemical formula and molecular structure of radical. In the ordered state,

  3. Boson sampling with displaced single-photon Fock states versus single-photon-added coherent states---The quantum-classical divide and computational-complexity transitions in linear optics

    E-print Network

    Kaushik P. Seshadreesan; Jonathan P. Olson; Keith R. Motes; Peter P. Rohde; Jonathan P. Dowling

    2015-02-27

    Boson sampling is a specific quantum computation, which is likely hard to implement efficiently on a classical computer. The task is to sample the output photon number distribution of a linear optical interferometric network, which is fed with single-photon Fock state inputs. A question that has been asked is if the sampling problems associated with any other input quantum states of light (other than the Fock states) to a linear optical network and suitable output detection strategies are also of similar computational complexity as boson sampling. We consider the states that differ from the Fock states by a displacement operation, namely the displaced Fock states and the photon-added coherent states. It is easy to show that the sampling problem associated with displaced single-photon Fock states and a displaced photon number detection scheme is in the same complexity class as boson sampling for all values of displacement. On the other hand, we show that the sampling problem associated with single-photon-added coherent states and the same displaced photon number detection scheme demonstrates a computational complexity transition. It transitions from being just as hard as boson sampling when the input coherent amplitudes are sufficiently small, to a classically simulatable problem in the limit of large coherent amplitudes.

  4. Modeling Symmetric Macromolecular Structures in Rosetta3

    PubMed Central

    DiMaio, Frank; Leaver-Fay, Andrew; Bradley, Phil; Baker, David; André, Ingemar

    2011-01-01

    Symmetric protein assemblies play important roles in many biochemical processes. However, the large size of such systems is challenging for traditional structure modeling methods. This paper describes the implementation of a general framework for modeling arbitrary symmetric systems in Rosetta3. We describe the various types of symmetries relevant to the study of protein structure that may be modeled using Rosetta's symmetric framework. We then describe how this symmetric framework is efficiently implemented within Rosetta, which restricts the conformational search space by sampling only symmetric degrees of freedom, and explicitly simulates only a subset of the interacting monomers. Finally, we describe structure prediction and design applications that utilize the Rosetta3 symmetric modeling capabilities, and provide a guide to running simulations on symmetric systems. PMID:21731614

  5. Introduction to Linear Dynamical Systems

    NSDL National Science Digital Library

    Boyd, Stephen

    Introduction to applied linear algebra and linear dynamical systems, with applications to circuits, signal processing, communications, and control systems.Topics include: Least-squares approximations of over-determined equations and least-norm solutions of underdetermined equations. Symmetric matrices, matrix norm and singular value decomposition. Eigenvalues, left and right eigenvectors, and dynamical interpretation. Matrix exponential, stability, and asymptotic behavior. Multi-input multi-output systems, impulse and step matrices; convolution and transfer matrix descriptions. Control, reachability, state transfer, and least-norm inputs. Observability and least-squares state estimation.Prerequisites: Exposure to linear algebra and matrices. You should have seen the following topics: matrices and vectors, (introductory) linear algebra; differential equations, Laplace transform, transfer functions. Exposure to topics such as control systems, circuits, signals and systems, or dynamics is not required, but can increase your appreciation.

  6. Matching method and exact solvability of discrete PT-symmetric square wells

    E-print Network

    Miloslav Znojil

    2006-05-24

    Discrete PT-symmetric square wells are studied. Their wave functions are found proportional to classical Tshebyshev polynomials of complex argument. The compact secular equations for energies are derived giving the real spectra in certain intervals of non-Hermiticity strengths Z. It is amusing to notice that although the known square well re-emerges in the usual continuum limit, a twice as rich, upside-down symmetric spectrum is exhibited by all its present discretized predecessors.

  7. Novel iron(III) complexes of tripodal and linear tetradentate bis(phenolate) ligands: close relevance to intradiol-cleaving catechol dioxygenases.

    PubMed

    Velusamy, Marappan; Palaniandavar, Mallayan; Gopalan, R Srinivasa; Kulkarni, G U

    2003-12-15

    Four new iron(III) complexes of the bis(phenolate) ligands N,N-dimethyl-N',N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine [H2(L1)], N,N-dimethyl-N',N'-bis(2-hydroxy-4-nitrobenzyl)ethylenediamine [H2(L2)], N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine [H2(L3)], and N,N'-dimethyl-N,N'-bis(2-hydroxy-4-nitrobenzyl)ethylenediamine [H2(L4)] have been isolated and studied as structural and functional models for the intradiol-cleaving catechol 1,2-dioxygenases (CTD). The complexes [Fe(L1)Cl] (1), [Fe(L2)(H2O)Cl] (2), [Fe(L3)Cl] (3), and [Fe(L4)(H2O)Cl] (4) have been characterized using absorption spectral and electrochemical techniques. The single-crystal X-ray structures of the ligand H2(L1) and the complexes 1 and 2 have been successfully determined. The tripodal ligand H2(L1) containing a N2O2 donor set represents the metal-binding region of the iron proteins. Complex 1 contains an FeN2O2Cl chromophore with a novel trigonal bipyramidal coordination geometry. While two phenolate oxygens and an amine nitrogen constitute the trigonal plane, the other amine nitrogen and chloride ion are located in the axial positions. In contrast, 2 exhibits a rhombically distorted octahedral coordination geometry for the FeN2O3Cl chromophore. Two phenolate oxygen atoms, an amine nitrogen atom, and a water molecule are located on the corners of a square plane with the axial positions being occupied by the other nitrogen atom and chloride ion. The interaction of the complexes with a few monodentate bases and phenolates and differently substituted catechols have been investigated using absorption spectral and electrochemical methods. The effect of substituents on the phenolate rings on the electronic spectral features and FeIII/FeII redox potentials of the complexes are discussed. The interaction of the complexes with catecholate anions reveals changes in the phenolate to iron(III) charge-transfer band and also the appearance of a low-energy catecholate to iron(III) charge-transfer band similar to catechol dioxygenase-substrate complexes. The redox behavior of the 1:1 adducts of the complexes with 3,5-di-tert-butylcatechol (H2DBC) has been also studied. The reactivities of the present complexes with H2DBC have been studied and illustrated. Interestingly, only 2 and 4 catalyze the intradiol-cleavage of H2DBC, the rate of oxygenation being much faster for 4. Also 2, but not 4, yields an extradiol cleavage product. The reactivity of the complexes could be illustrated not on the basis of the Lewis acidity of the complexes alone but by assuming that the product release is the rate-determining phase of the catalytic reaction. PMID:14658880

  8. Spherically symmetric canonical quantum gravity

    NASA Astrophysics Data System (ADS)

    Brahma, Suddhasattwa

    2015-06-01

    Canonical quantization of spherically symmetric space-times is carried out, using real-valued densitized triads and extrinsic curvature components, with specific factor-ordering choices ensuring in an anomaly free quantum constraint algebra. Comparison with previous work [Nucl. Phys. B399, 211 (1993)] reveals that the resulting physical Hilbert space has the same form, although the basic canonical variables are different in the two approaches. As an extension, holonomy modifications from loop quantum gravity are shown to deform the Dirac space-time algebra, while going beyond "effective" calculations.

  9. Symmetric spaces of exceptional groups

    SciTech Connect

    Boya, L. J., E-mail: luisjo@unizar.e [Universidad de Zaragoza, Departamento de Fisica Teorica (Spain)

    2010-02-15

    We address the problem of the reasons for the existence of 12 symmetric spaces with the exceptional Lie groups. The 1 + 2 cases for G{sub 2} and F{sub 4}, respectively, are easily explained from the octonionic nature of these groups. The 4 + 3 + 2 cases on the E{sub 6,7,8} series require the magic square of Freudenthal and, for the split case, an appeal to the supergravity chain in 5, 4, and 3 space-time dimensions.

  10. AN EXTENSION OF THE DIVIDE-AND-CONQUER METHOD FOR A CLASS OF SYMMETRIC BLOCK-TRIDIAGONAL

    E-print Network

    Ward, Robert C.

    of Computer Science, University of Tennessee, 203 Claxton Complex, 1122 Volun- teer Blvd., Knoxville, TN 37996 if all eigenvalues and eigenvectors of a large dense or banded symmetric matrix are to be computed [8

  11. The Stark Effect in Linear Potentials

    ERIC Educational Resources Information Center

    Robinett, R. W.

    2010-01-01

    We examine the Stark effect (the second-order shifts in the energy spectrum due to an external constant force) for two one-dimensional model quantum mechanical systems described by linear potentials, the so-called quantum bouncer (defined by V(z) = Fz for z greater than 0 and V(z) = [infinity] for z less than 0) and the symmetric linear potential…

  12. Risk aversion in symmetric and asymmetric contests

    Microsoft Academic Search

    Richard Cornes; Roger Hartley

    2008-01-01

    We analyze existence, uniqueness and properties of equilibria in incompletely discriminating Tullock contests with logistic\\u000a contest success functions, when contestants are risk averse. We prove that a Nash equilibrium for such a contest exists, but\\u000a give an example of a symmetric contest with both symmetric and asymmetric equilibria, showing that risk aversion may lead\\u000a to multiple equilibria. Symmetric contests have

  13. Recursive partitioned inversion of large (1500 x 1500) symmetric matrices

    NASA Technical Reports Server (NTRS)

    Putney, B. H.; Brownd, J. E.; Gomez, R. A.

    1976-01-01

    A recursive algorithm was designed to invert large, dense, symmetric, positive definite matrices using small amounts of computer core, i.e., a small fraction of the core needed to store the complete matrix. The described algorithm is a generalized Gaussian elimination technique. Other algorithms are also discussed for the Cholesky decomposition and step inversion techniques. The purpose of the inversion algorithm is to solve large linear systems of normal equations generated by working geodetic problems. The algorithm was incorporated into a computer program called SOLVE. In the past the SOLVE program has been used in obtaining solutions published as the Goddard earth models.

  14. BDDC for nonsymmetric positive definite and symmetric indefinite problems

    SciTech Connect

    Tu, Xuemin; Li, Jing

    2008-12-10

    The balancing domain decomposition methods by constraints are extended to solving both nonsymmetric, positive definite and symmetric, indefinite linear systems. In both cases, certain nonstandard primal constraints are included in the coarse problems of BDDC algorithms to accelerate the convergence. Under the assumption that the subdomain size is small enough, a convergence rate estimate for the GMRES iteration is established that the rate is independent of the number of subdomains and depends only slightly on the subdomain problem size. Numerical experiments for several two-dimensional examples illustrate the fast convergence of the proposed algorithms.

  15. Propagation Effects on the Breakdown of a Linear Amplifier Model: Complex-Mass Schrödinger Equation Driven by the Square of a Gaussian Field

    NASA Astrophysics Data System (ADS)

    Mounaix, Philippe; Collet, Pierre; Lebowitz, Joel L.

    2006-06-01

    Solutions to the equation [InlineMediaObject not available: see fulltext.] are investigated, where S( x, t) is a complex Gaussian field with zero mean and specified covariance, and m?0 is a complex mass with Im( m) ? 0. For real m this equation describes the backscattering of a smoothed laser beam by an optically active medium. Assuming that S( x, t) is the sum of a finite number of independent complex Gaussian random variables, we obtain an expression for the value of ? at which the q th moment of [InlineMediaObject not available: see fulltext.] w.r.t. the Gaussian field S diverges. This value is found to be less or equal for all m ? 0, Im( m) ? 0 and | m|<+? than for | m| = +?, i.e. when the [InlineMediaObject not available: see fulltext.] term is absent. Our solution is based on a distributional formulation of the Feynman path-integral and the Paley-Wiener theorem.

  16. POVM construction: a simple recipe with applications to symmetric states

    E-print Network

    Swarnamala Sirsi; Karthik Bharath; S. P. Shilpashree

    2015-05-01

    We propose a simple method for constructing POVMs using any set of matrices which form an orthonormal basis for the space of complex matrices. Considering the orthonormal set of irreducible spherical tensors, we examine the properties of the construction on the $N+1$-dimensional subspace of the $2^N$-dimensional Hilbert space of $N$ qubits comprising the permutationally symmetric states. Similar in spirit to Neumark's result on realization of a POVM as a projective measurement, we present a method to physically realize the constructed POVMs for symmetric states using the Clebsch--Gordan decomposition of the tensor product of irreducible representations of the rotation group. We illustrate the proposed construction on a spin-1 system, and show that it is possible to generate entangled states from separable ones.

  17. Nonlinearly PT-symmetric systems: Spontaneous symmetry breaking and transmission resonances

    SciTech Connect

    Miroshnichenko, Andrey E.; Kivshar, Yuri S. [Nonlinear Physics Centre, Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Malomed, Boris A. [Department of Physical Electronics, Faculty of Engineering, Tel Aviv University, IL-69978 Tel Aviv (Israel)

    2011-07-15

    We consider a class of PT-symmetric systems which include mutually matched nonlinear loss and gain (in other words, a class of PT-invariant Hamiltonians in which both the harmonic and anharmonic parts are non-Hermitian). For a basic system in the form of a dimer, symmetric and asymmetric eigenstates, including multistable ones, are found analytically. We demonstrate that, if coupled to a linear chain, such a nonlinear PT-symmetric dimer generates previously unexplored types of nonlinear Fano resonances, with completely suppressed or greatly amplified transmission, as well as a regime similar to the electromagnetically induced transparency. The implementation of the systems is possible in various media admitting controllable linear and nonlinear amplification of waves.

  18. Symmetric and Asymmetric Encryption GUSTAVUS J. SIMMONS

    E-print Network

    Lee, Ruby B.

    Symmetric and Asymmetric Encryption GUSTAVUS J. SIMMONS Sandm Laboratories, Albuquerque, New Mexico;306 · Gustavus J. Simmons CONTENTS INTRODUCTION 1 CLASSICAL CRYPTOGRAPHY 2 READER'S GUIDE 3 THE COMMUNICATIONS

  19. Phasor Analysis of Linear Mechanical Systems and Linear Differential Equations

    E-print Network

    Paden, Brad

    Phasor Analysis of Linear Mechanical Systems and Linear Differential Equations ME104, Prof. B equations, the phasor analysis we learned for electric circuits. Recall how we derived the complex impedance, we see that we can jump directly from (1) to (5) by making the substitution j dt d (7) Phasor

  20. Phasor Analysis of Linear Mechanical Systems and Linear Differential Equations

    E-print Network

    Paden, Brad

    Phasor Analysis of Linear Mechanical Systems and Linear Differential Equations ME104, Prof. B equations, the phasor analysis we learned for electric circuits. Recall how we derived the complex impedance see that we can jump directly from (1) to (5) by making the substitution j dt d (7) Phasor Analysis

  1. Experimental characterization of qutrits using symmetric informationally complete positive operator-valued measurements

    Microsoft Academic Search

    Z. E. D. Medendorp; L. K. Shalm; A. M. Steinberg; F. A. Torres-Ruiz; G. N. M. Tabia; C. A. Fuchs

    2011-01-01

    Generalized quantum measurements [also known as positive operator-valued measures (POVMs)] are of great importance in quantum information and quantum foundations but are often difficult to perform. We present an experimental approach which can in principle be used to perform arbitrary POVMs in a linear-optical context. One of the most interesting POVMs, the symmetric informationally complete (SIC) POVM, is the most

  2. Continuous-time symmetric Hopfield nets are computationally universal.

    PubMed

    Síma, Jirí; Orponen, Pekka

    2003-03-01

    We establish a fundamental result in the theory of computation by continuous-time dynamical systems by showing that systems corresponding to so-called continuous-time symmetric Hopfield nets are capable of general computation. As is well known, such networks have very constrained Lyapunov-function controlled dynamics. Nevertheless, we show that they are universal and efficient computational devices, in the sense that any convergent synchronous fully parallel computation by a recurrent network of n discrete-time binary neurons, with in general asymmetric coupling weights, can be simulated by a symmetric continuous-time Hopfield net containing only 18n + 7 units employing the saturated-linear activation function. Moreover, if the asymmetric network has maximum integer weight size w(max) and converges in discrete time t*, then the corresponding Hopfield net can be designed to operate in continuous time Theta(t*/epsilon) for any epsilon > 0 such that w(max)2(12n) symmetric Hopfield nets. PMID:12620163

  3. Linear ubiquitination in immunity.

    PubMed

    Shimizu, Yutaka; Taraborrelli, Lucia; Walczak, Henning

    2015-07-01

    Linear ubiquitination is a post-translational protein modification recently discovered to be crucial for innate and adaptive immune signaling. The function of linear ubiquitin chains is regulated at multiple levels: generation, recognition, and removal. These chains are generated by the linear ubiquitin chain assembly complex (LUBAC), the only known ubiquitin E3 capable of forming the linear ubiquitin linkage de novo. LUBAC is not only relevant for activation of nuclear factor-?B (NF-?B) and mitogen-activated protein kinases (MAPKs) in various signaling pathways, but importantly, it also regulates cell death downstream of immune receptors capable of inducing this response. Recognition of the linear ubiquitin linkage is specifically mediated by certain ubiquitin receptors, which is crucial for translation into the intended signaling outputs. LUBAC deficiency results in attenuated gene activation and increased cell death, causing pathologic conditions in both, mice, and humans. Removal of ubiquitin chains is mediated by deubiquitinases (DUBs). Two of them, OTULIN and CYLD, are constitutively associated with LUBAC. Here, we review the current knowledge on linear ubiquitination in immune signaling pathways and the biochemical mechanisms as to how linear polyubiquitin exerts its functions distinctly from those of other ubiquitin linkage types. PMID:26085216

  4. A QMR-based interior-point algorithm for solving linear programs

    Microsoft Academic Search

    Roland W. Freund; Florian Jarre

    1997-01-01

    A new approach for the implementation of interior-point methods for solving linear programs is proposed. Its main feature\\u000a is the iterative solution of the symmetric, but highly indefinite 2×2-block systems of linear equations that arise within\\u000a the interior-point algorithm. These linear systems are solved by a symmetric variant of the quasi-minimal residual (QMR) algorithm,\\u000a which is an iterative solver for

  5. Symmetrical mixtures in external fields

    NASA Astrophysics Data System (ADS)

    Materniak, S.; Patrykiejew, A.

    2013-07-01

    We have studied the behavior of symmetrical binary mixtures of Lennard-Jones particles in contact with strongly adsorbing walls using Monte Carlo simulation methods in the grand canonical and semi-grand canonical ensembles. Two types of the surface potential have been applied. The first depends on the distance from the surface only, while the second involves periodic modulations in the directions parallel to the wall. In the latter case, it has been assumed that the solid substrate is a fcc crystal with the surface being the (100) face. We have considered the systems in which the surface potential is strong enough to induce the layer-by-layer adsorption at low temperatures and discussed the interplay between the demixing transition and the structure of thin films for several systems characterized by different parameters describing the interactions in the system.

  6. Symmetrical mixtures in external fields.

    PubMed

    Materniak, S; Patrykiejew, A

    2013-07-01

    We have studied the behavior of symmetrical binary mixtures of Lennard-Jones particles in contact with strongly adsorbing walls using Monte Carlo simulation methods in the grand canonical and semi-grand canonical ensembles. Two types of the surface potential have been applied. The first depends on the distance from the surface only, while the second involves periodic modulations in the directions parallel to the wall. In the latter case, it has been assumed that the solid substrate is a fcc crystal with the surface being the (100) face. We have considered the systems in which the surface potential is strong enough to induce the layer-by-layer adsorption at low temperatures and discussed the interplay between the demixing transition and the structure of thin films for several systems characterized by different parameters describing the interactions in the system. PMID:23822318

  7. Compactifications of Bruhat-Tits buildings associated to linear representations

    E-print Network

    Werner, Annette

    Compactifications of Bruhat-Tits buildings associated to linear representations Annette Werner, geometrically irreducible linear representation of G we define a compactification of the associated Bruhat-Tits compactifications of Bruhat-Tits buildings, which are analogous to Satake compactifications of symmetric spaces

  8. Permutation inference for the general linear model

    PubMed Central

    Winkler, Anderson M.; Ridgway, Gerard R.; Webster, Matthew A.; Smith, Stephen M.; Nichols, Thomas E.

    2014-01-01

    Permutation methods can provide exact control of false positives and allow the use of non-standard statistics, making only weak assumptions about the data. With the availability of fast and inexpensive computing, their main limitation would be some lack of flexibility to work with arbitrary experimental designs. In this paper we report on results on approximate permutation methods that are more flexible with respect to the experimental design and nuisance variables, and conduct detailed simulations to identify the best method for settings that are typical for imaging research scenarios. We present a generic framework for permutation inference for complex general linear models (glms) when the errors are exchangeable and/or have a symmetric distribution, and show that, even in the presence of nuisance effects, these permutation inferences are powerful while providing excellent control of false positives in a wide range of common and relevant imaging research scenarios. We also demonstrate how the inference on glm parameters, originally intended for independent data, can be used in certain special but useful cases in which independence is violated. Detailed examples of common neuroimaging applications are provided, as well as a complete algorithm – the “randomise” algorithm – for permutation inference with the glm. PMID:24530839

  9. The Magic Square and Symmetric Compositions II

    Microsoft Academic Search

    Alberto Elduque

    2005-01-01

    The construction of Freudenthal's Magic Square, which contains the exceptional simple Lie algebras, in terms of symmetric composition algebras is further developed here. The para-Hurwitz algebras, which form a subclass of the symmetric composition algebras, will be defined, in the split case, in terms of the natural two dimensional module for the simple Lie algebra sl(2). As a consequence, it

  10. Results on rotation symmetric bent functions

    Microsoft Academic Search

    Deepak Kumar Dalai; Subhamoy Maitra; Sumanta Sarkar

    2009-01-01

    In this paper we analyze the combinatorial properties related to the Walsh spectra of rotation symmetric Boolean functions on even number of variables. These results are then applied in studying rotation symmetric bent functions. 2n n ) than the total space of Boolean functions (22 n ) and the set contains functions with very good cryptographic properties. It has been

  11. EM Algorithm for Symmetric Causal Independence Models

    Microsoft Academic Search

    Rasa Jurgelenaite; Tom Heskes

    2006-01-01

    Causal independence modelling is a well-known method both for reducing the size of probability tables and for explaining the underly- ing mechanisms in Bayesian networks. In this paper, we present the EM algorithm to learn the parameters in causal independence models based on the symmetric Boolean function. The developed algorithm enables us to assess the practical usefulness of the symmetric

  12. Error correction and symmetrization in quantum computers

    Microsoft Academic Search

    Asher Peres

    1996-01-01

    Errors in quantum computers are of two kinds: sudden perturbations to isolated qubits, and slow random drifts of all the qubits. The latter may be reduced, but not eliminated, by means of symmetrization, namely by using many replicas of the computer, and forcing their joint quantum state to be completely symmetric. On the other hand, isolated errors can be corrected

  13. Detecting Symmetry and Symmetric Constellations of Features

    Microsoft Academic Search

    Gareth Loyand; Jan-olof Eklundh

    2006-01-01

    A novel and efficient method is presented for grouping feature points on the basis of their underlying symmetry and characterising the symmetries present in an image. We show how symmetric pairs of features can be efficiently detected, how the symmetry bonding each pair is extracted and evaluated, and how these can be grouped into symmetric constellations that specify the domi-

  14. The free-electron laser in a symmetrical confocal resonator

    NASA Technical Reports Server (NTRS)

    Ozcan, Meric; Pantell, Richard H.

    1993-01-01

    A tapered wiggler is used in a FEL oscillator to improve the saturation efficiency. During signal buildup the tapered wiggler does not provide optimum phase synchronism between the electron beam and the electromagnetic wave, resulting in an appreciable loss in small-signal gain. This problem can be ameliorated by using a multicomponent wiggler, which is a combination of a uniform wiggler and a tapered section. During buildup, gain is primarily contributed by the linear element, and at high power levels the gain and efficiency are enhanced by the taper. Ideally, one would like to have the optical waist location near the linear section at small-signal levels and at near the tapered section at high power levels. Placing the FEL in a symmetrical confocal resonator approaches this desired effect automatically since it has the unique characteristic that a stable mode exists for all locations of the waist of a Gaussian beam along the axis of the interferometer.

  15. Whorled hairless nevus of the scalp, linear hyperpigmentation, and telangiectatic nevi of the lower limbs: a novel variant of the "phacomatosis complex".

    PubMed

    Castori, Marco; Scarciolla, Oronzo; Morlino, Silvia; Manente, Liborio; Biscaglia, Assunta; Fragasso, Alberto; Grammatico, Paola

    2012-02-01

    The term "phacomatosis" refers to a growing number of sporadic genetic skin disorders characterized by the combination of two or more different nevi and possibly resulting from non-allelic twin spotting. While phacomatosis pigmentovascularis (PPV) and pigmentokeratotica represent the most common patterns, some patients do not fit with either condition and are temporarily classified as unique phenotypes. We report on an 8-year-old boy with striking right hemihypoplasia, resulting in limb asymmetry and fixed dislocation of right hip. Skin on the affected side showed three distinct nevi: (i) A whorled, hairless nevus of the scalp in close proximity with (ii) epidermal hyperpigmentation following lines of Blaschko on the neck and right upper limb, and (iii) multiple telangiectatic nevi of the right lower limb and hemiscrotum. Didymosis atricho-melanotica was proposed for the combination of adjacent patchy congenital alopecia and linear hyperpigmentation, while phacomatosis atricho-pigmento-vascularis appears to define the entire cutaneous phenotype, thus implying the involvement of three neighboring loci influencing the development of distinct constituents of the skin. Given the striking asymmetry of the observed phenotype, the effect of mosaicism (either genomic or functional) for a mutation in a single gene with pleiotropic action and influenced by the lateralization pattern of early development cannot be excluded. PMID:22247078

  16. Application of non-linear angle synchronous spectrofluorimetry to the determination of complex mixtures of drugs in urine: A comparative study

    NASA Astrophysics Data System (ADS)

    Murillo Pulgarín, J. A.; Alañón Molina, A.; Boras, N.

    2012-12-01

    Synchronous fluorescence spectroscopy (SFS) is a rapid, sensitive and non-destructive method suitable for the analysis of multifluorophoric mixtures. In this study non linear variable angle synchronous spectrofluorimetry was applied to the determination of three fluoroquinololes in urine. Although this technique provides very good results, total resolution of multicomponent mixtures is not always achieved when the spectral profiles strongly overlap. Partial least-squares regression (PLS-1) was utilized to a develop calibration model that related synchronous fluorescence spectra to the analytical concentration of fluoroquinolones in the presence of urine. The same multicomponent mixture was determined using excitation emission matrix fluorescence (EEMF) along with N-way partial least squares regression (N-PLS and U-PLS). The determination was carried out in micellar medium 0.01 M with a pH of 4.8 provided by 0.2 M sodium acetate/acetic acid buffer. A central composite design was selected to obtain a calibration matrix of 25 standards plus a blank sample. The proposed methods were validated by application to a test set of synthetic samples. The results show that SFS with PLS-1 is a better method compared to EEMF with N-PLS or U-PLS because of the low RMSEP values of the former.

  17. Towards an exact theory of linear absorbance and circular dichroism of pigment-protein complexes: Importance of non-secular contributions

    NASA Astrophysics Data System (ADS)

    Dinh, Thanh-Chung; Renger, Thomas

    2015-01-01

    A challenge for the theory of optical spectra of pigment-protein complexes is the equal strength of the pigment-pigment and the pigment-protein couplings. Treating both on an equal footing so far can only be managed by numerically costly approaches. Here, we exploit recent results on a normal mode analysis derived spectral density that revealed the dominance of the diagonal matrix elements of the exciton-vibrational coupling in the exciton state representation. We use a cumulant expansion technique that treats the diagonal parts exactly, includes an infinite summation of the off-diagonal parts in secular and Markov approximations, and provides a systematic perturbative way to include non-secular and non-Markov corrections. The theory is applied to a model dimer and to chlorophyll (Chl) a and Chl b homodimers of the reconstituted water-soluble chlorophyll-binding protein (WSCP) from cauliflower. The model calculations reveal that the non-secular/non-Markov effects redistribute oscillator strength from the strong to the weak exciton transition in absorbance and they diminish the rotational strength of the exciton transitions in circular dichroism. The magnitude of these corrections is in a few percent range of the overall signal, providing a quantitative explanation of the success of time-local convolution-less density matrix theory applied earlier. A close examination of the optical spectra of Chl a and Chl b homodimers in WSCP suggests that the opening angle between Qy transition dipole moments in Chl b homodimers is larger by about 9? than for Chl a homodimers for which a crystal structure of a related WSCP complex exists. It remains to be investigated whether this change is due to a different mutual geometry of the pigments or due to the different electronic structures of Chl a and Chl b.

  18. Towards an exact theory of linear absorbance and circular dichroism of pigment-protein complexes: importance of non-secular contributions.

    PubMed

    Dinh, Thanh-Chung; Renger, Thomas

    2015-01-21

    A challenge for the theory of optical spectra of pigment-protein complexes is the equal strength of the pigment-pigment and the pigment-protein couplings. Treating both on an equal footing so far can only be managed by numerically costly approaches. Here, we exploit recent results on a normal mode analysis derived spectral density that revealed the dominance of the diagonal matrix elements of the exciton-vibrational coupling in the exciton state representation. We use a cumulant expansion technique that treats the diagonal parts exactly, includes an infinite summation of the off-diagonal parts in secular and Markov approximations, and provides a systematic perturbative way to include non-secular and non-Markov corrections. The theory is applied to a model dimer and to chlorophyll (Chl) a and Chl b homodimers of the reconstituted water-soluble chlorophyll-binding protein (WSCP) from cauliflower. The model calculations reveal that the non-secular/non-Markov effects redistribute oscillator strength from the strong to the weak exciton transition in absorbance and they diminish the rotational strength of the exciton transitions in circular dichroism. The magnitude of these corrections is in a few percent range of the overall signal, providing a quantitative explanation of the success of time-local convolution-less density matrix theory applied earlier. A close examination of the optical spectra of Chl a and Chl b homodimers in WSCP suggests that the opening angle between Qy transition dipole moments in Chl b homodimers is larger by about 9(?) than for Chl a homodimers for which a crystal structure of a related WSCP complex exists. It remains to be investigated whether this change is due to a different mutual geometry of the pigments or due to the different electronic structures of Chl a and Chl b. PMID:25612686

  19. High-Order Fluxes for Conservative Skew-Symmetric-like Schemes in Structured Meshes: Application to Compressible Flows

    Microsoft Academic Search

    F. Ducros; F. Laporte; T. Soulères; V. Guinot; P. Moinat; B. Caruelle

    2000-01-01

    Developing high-order non-dissipative schemes is an important research task for both steady and unsteady flow computations. We take as a starting point the “built-in” de-aliasing property of the discretized skew-symmetric form for the non-linear terms of the Navier–Stokes equations, recalled in Kravchenko and Moin [1]. Two families of high-order locally conservative schemes matching this discretized skew-symmetric form are considered and

  20. Spatial-frequency Fourier polarimetry of the complex degree of mutual anisotropy of linear and circular birefringence in the diagnostics of oncological changes in morphological structure of biological tissues

    SciTech Connect

    Ushenko, Yu A; Gorskii, M P; Dubolazov, A V; Motrich, A V; Ushenko, V A; Sidor, M I [Yuriy Fedkovych Chernivtsi National University, Chernivtsi (Ukraine)

    2012-08-31

    Theory of polarisation-correlation analysis of laser images of histological sections of biopsy material from cervix tissue based on spatial frequency selection of linear and circular birefringence mechanisms is formulated. Comparative results of measuring the coordinate distributions of the complex degree of mutual anisotropy (CDMA), produced by fibrillar networks formed by myosin and collagen fibres of cervix tissue in different pathological conditions, namely, pre-cancer (dysplasia) and cancer (adenocarcinoma), are presented. The values and variation ranges of statistical (moments of the first - fourth order), correlation (excess-autocorrelation functions), and fractal (slopes of approximating curves and dispersion of extrema of logarithmic dependences of power spectra) parameters of the CDMA coordinate distributions are studied. Objective criteria for pathology diagnostics and differentiation of its severity degree are determined. (image processing)

  1. An accurate Fourier splitting scheme for solving the cubic quintic complex Ginzburg-Landau equation

    NASA Astrophysics Data System (ADS)

    Mohammedi, Tidjani; Aissat, Abdelkader

    2014-11-01

    In this paper, we present a splitting scheme for the pseudo-spectral numerical method namely the Split-Step Fourier method (SSFM), in our approach we expand the exponential term in a manner that a succession of linear and nonlinear terms are distributed uniformly along one step size, the splitting will be performed symmetrically, this new scheme will be tested on one of the most used nonlinear partial deferential equation in optics, namely the cubic quintic complex Ginzburg-Landau (CQCGL) equation, in this work we demonstrate that the accuracy of the Split Step Fourier method scheme can be improved by expanding and distributing it in small parts within one step.

  2. Solitons in PT-symmetric periodic systems with the quadratic nonlinearity

    NASA Astrophysics Data System (ADS)

    Moreira, F. C.; Konotop, V. V.; Malomed, B. A.

    2013-01-01

    We introduce a one-dimensional system combining the PT-symmetric complex periodic potential and the ?(2) (second-harmonic-generating) nonlinearity. The imaginary part of the potential, which represents spatially separated and mutually balanced gain and loss, affects only the fundamental-frequency (FF) wave, while the real potential acts on the second-harmonic (SH) component too. Soliton modes are constructed, and their stability is investigated (by means of the linearization and direct simulations) in semi-infinite and finite gaps in the corresponding spectrum, starting from the bifurcation which generates the solitons from edges of the gaps’ edges. Families of solitons embedded into the continuous spectrum of the SH component are found too, and it is demonstrated that a part of the families of these embedded solitons is stable. The analysis is focused on effects produced by the variation of the strength of the imaginary part of the potential, which is a specific characteristic of the PT system. The consideration is performed chiefly for the most relevant case of matched real potentials acting on the FF and SH components. The case of the real potential acting solely on the FF component is briefly considered too.

  3. Honors problem 1: Complex numbers. Arithmetic of complex numbers

    E-print Network

    Leininger, Christopher J.

    Honors problem 1: Complex numbers. Arithmetic of complex numbers Recall that the complex numbers identify the complex numbers with the set of linear polynomials with real coefficients). The numbers as a subset of the complex numbers by identifying the real number a with a+0i. The imaginary numbers

  4. Honors problem 1: Complex numbers. Arithmetic of complex numbers

    E-print Network

    Leininger, Christopher J.

    Honors problem 1: Complex numbers. Arithmetic of complex numbers Recall that the complex numbers we can identify the complex numbers with the set of linear polynomials with real coefficients as a subset of the complex numbers by identifying the real number a with a + 0i. The imaginary numbers

  5. $\\mathcal{PT}$-symmetric microring laser-absorber

    E-print Network

    Stefano Longhi; Liang Feng

    2014-07-17

    The lasing and coherent perfect absorption (CPA) properties of $\\mathcal{PT}$-symmetric microrings with mixed index and gain gratings, externally coupled to a bus waveguide, are theoretically investigated. For a complex grating at the $\\mathcal{PT}$ symmetry breaking point, perfect unidirectional (either clockwise or counterclockwise) laser emission can be realized, however the grating does not discriminate longitudinal modes and CPA can not be simultaneously achieved. Above the grating $\\mathcal{PT}$ symmetry breaking point, single mode emission and simultaneous CPA can be obtained, with unbalanced and controllable excitation of clockwise and counterclockwise modes in the ring.

  6. Symmetric Tensor Decomposition Description of Fermionic Many-Body Wavefunctions

    E-print Network

    Uemura, Wataru

    2012-01-01

    The configuration interaction (CI) is a versatile wavefunction theory for interacting fermions but it involves an extremely long CI series. Using a symmetric tensor decomposition (STD) method, we convert the CI series into a compact and numerically tractable form. The converted series encompasses the Hartree-Fock state in the first term and rapidly converges to the full-CI state, as numerically tested using small molecules. Provided that the length of the STD-CI series grows only moderately with the increasing complexity of the system, the new method will serve as one of the alternative variational methods to achieve full-CI with enhanced practicability.

  7. The Topology of Three-Dimensional Symmetric Tensor Fields

    NASA Technical Reports Server (NTRS)

    Lavin, Yingmei; Levy, Yuval; Hesselink, Lambertus

    1994-01-01

    We study the topology of 3-D symmetric tensor fields. The goal is to represent their complex structure by a simple set of carefully chosen points and lines analogous to vector field topology. The basic constituents of tensor topology are the degenerate points, or points where eigenvalues are equal to each other. First, we introduce a new method for locating 3-D degenerate points. We then extract the topological skeletons of the eigenvector fields and use them for a compact, comprehensive description of the tensor field. Finally, we demonstrate the use of tensor field topology for the interpretation of the two-force Boussinesq problem.

  8. Weyl Group Symmetric Functions Representation Theory of Lie Algebras

    E-print Network

    Ram, Arun

    of symmetric functions in the spirit of Macdonald's book [Mac] for Weyl groups other than the symmetric group of the classical symmetric function theory. See [Mac] Chapter 1 for a complete treatment. Fix a positive integer n

  9. Invertible extensions of continuous maps Real symmetric functions

    E-print Network

    Mortini, Raymond

    Invertible extensions of continuous maps Real symmetric functions Covering dimension Bass and topological stable rank Real symmetric extensions of invertible tuples of multivariable continuous functions;Invertible extensions of continuous maps Real symmetric functions Covering dimension Bass and topological

  10. Complex Trajectories of a Simple Pendulum

    E-print Network

    Carl M. Bender; Darryl D. Holm; Daniel W. Hook

    2006-09-25

    The motion of a classical pendulum in a gravitational field of strength g is explored. The complex trajectories as well as the real ones are determined. If g is taken to be imaginary, the Hamiltonian that describes the pendulum becomes PT-symmetric. The classical motion for this PT-symmetric Hamiltonian is examined in detail. The complex motion of this pendulum in the presence of an external periodic forcing term is also studied.

  11. A terminal, fluxional ?4-benzene complex with a thermally accessible triplet state is the primary photoproduct in the intercyclobutadiene haptotropism of (CpCo)phenylenes.

    PubMed

    Albright, Thomas A; Drissi, Rima; Gandon, Vincent; Oldenhof, Sander; Oloba-Whenu, Oluwakemi A; Padilla, Robin; Shen, Hao; Vollhardt, K Peter C; Vreeken, Vincent

    2015-03-16

    Low-temperature irradiation of linear [3]- and [4]phenylene cyclopentadienylcobalt complexes generates labile, fluxional ?(4)-arene complexes, in which the metal resides on the terminal ring. Warming induces a haptotropic shift to the neighboring cyclobutadiene rings, followed by the previously reported intercyclobutadiene migration. NMR scrutiny of the primary photoproduct reveals a thermally accessible 16-electron cobalt ?(2)-triplet species, which, according to DFT computations, is responsible for the rapid symmetrization of the molecules along their long axes. Calculations indicate that the entire haptotropic manifold along the phenylene frame is governed by dual-state reactivity of alternating 18-electron singlets and 16-electron triplets. PMID:25644142

  12. Baryon symmetric big bang cosmology

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1978-01-01

    Both the quantum theory and Einsteins theory of special relativity lead to the supposition that matter and antimatter were produced in equal quantities during the big bang. It is noted that local matter/antimatter asymmetries may be reconciled with universal symmetry by assuming (1) a slight imbalance of matter over antimatter in the early universe, annihilation, and a subsequent remainder of matter; (2) localized regions of excess for one or the other type of matter as an initial condition; and (3) an extremely dense, high temperature state with zero net baryon number; i.e., matter/antimatter symmetry. Attention is given to the third assumption, which is the simplest and the most in keeping with current knowledge of the cosmos, especially as pertains the universality of 3 K background radiation. Mechanisms of galaxy formation are discussed, whereby matter and antimatter might have collided and annihilated each other, or have coexisted (and continue to coexist) at vast distances. It is pointed out that baryon symmetric big bang cosmology could probably be proved if an antinucleus could be detected in cosmic radiation.

  13. Self-gravitating spherically symmetric solutions in scalar-torsion theories

    NASA Astrophysics Data System (ADS)

    Kofinas, Georgios; Papantonopoulos, Eleftherios; Saridakis, Emmanuel N.

    2015-05-01

    We study spherically symmetric solutions in scalar-torsion gravity theories in which a scalar field is coupled to torsion with a derivative coupling. We obtain the general field equations from which we extract a decoupled master equation, the solution of which leads to the specification of all other unknown functions. We first obtain an exact solution which represents a new wormholelike solution dressed with a regular scalar field. Then, we find large distance linearized spherically symmetric solutions in which the space asymptotically is anti-de Sitter.

  14. Generalized universal cloning and purification in quantum information by multistep state symmetrization

    NASA Astrophysics Data System (ADS)

    Masullo, L.; Ricci, M.; de Martini, F.

    2005-12-01

    A general multistep linear state symmetrization device for photonic qubits is presented together with the experimental realizations of the 1?3 and 2?3 universal optimal quantum cloning machines and of a 3-qubit purification procedure. Since the present method exploits the bosonic nature of the photons, it can be applied to any particle obeying to the Bose statistics. On a technological perspective, the present protocol is expected to find relevant applications as a multiqubit symmetrization device to be used in modern quantum-information networks.

  15. On the local form of static plane symmetric space-times in the presence of matter

    E-print Network

    Leandro G. Gomes

    2015-02-10

    For any configuration of a static plane-symmetric distribution of matter along space-time, there are coordinates where the metric can be put explicitly as a functional of the energy density and pressures. It satisfies Einstein equations as far as we require the conservation of the energy-momentum tensor, which is the single ODE for self-gravitating hydrostatic equilibrium. As a direct application, a general solution is given when the pressures are linearly related to the energy density, recovering, as special cases, most of known solutions of static plane-symmetric Einstein equations.

  16. Symmetric Informationally Complete Measurements of Arbitrary Rank

    E-print Network

    D. M. Appleby

    2006-11-27

    There has been much interest in so-called SIC-POVMs: rank 1 symmetric informationally complete positive operator valued measures. In this paper we discuss the larger class of POVMs which are symmetric and informationally complete but not necessarily rank 1. This class of POVMs is of some independent interest. In particular it includes a POVM which is closely related to the discrete Wigner function. However, it is interesting mainly because of the light it casts on the problem of constructing rank 1 symmetric informationally complete POVMs. In this connection we derive an extremal condition alternative to the one derived by Renes et al.

  17. Characterization of Randomly Time-Variant Linear Channels

    Microsoft Academic Search

    P. Bello

    1963-01-01

    This paper is concerned with various aspects of the characterization of randomly time-variant linear channels. At the outset it is demonstrated that time-varying linear channels (or filters) may be characterized in an interesting symmetrical manner in time and frequency variables by arranging system functions in (timefrequency) dual pairs. Following this a statistical characterization of randomly time-variant linear channels is carried

  18. Symmetric and asymmetric hybridization in citrus spp.

    E-print Network

    Bona, Claudine M.

    2009-05-15

    it difficult to create large segregating populations for selection. Somatic hybridization by protoplast fusion circumvents sexual incompatibilities and is a powerful tool in genetic improvement. Symmetric and asymmetric hybdridization (gamma irradiation plus...

  19. Dual PT-Symmetric Quantum Field Theories

    E-print Network

    Bender, C M; Rivers, R J

    2005-01-01

    Some quantum field theories described by non-Hermitian Hamiltonians are investigated. It is shown that for the case of a free fermion field theory with a $\\gamma_5$ mass term the Hamiltonian is $\\cal PT$-symmetric. Depending on the mass parameter this symmetry may be either broken or unbroken. When the $\\cal PT$ symmetry is unbroken, the spectrum of the quantum field theory is real. For the $\\cal PT$-symmetric version of the massive Thirring model in two-dimensional space-time, which is dual to the $\\cal PT$-symmetric scalar Sine-Gordon model, an exact construction of the $\\cal C$ operator is given. It is shown that the $\\cal PT$-symmetric massive Thirring and Sine-Gordon models are equivalent to the conventional Hermitian massive Thirring and Sine-Gordon models with appropriately shifted masses.

  20. On Blockwise Symmetric Signatures for JinYi Cai 1 and Pinyan Lu 2#

    E-print Network

    Cai, Jin-Yi

    computation e#ciently. Valiant's theory of matchgate and holographic algorithms [10, 12] is one a classification of block­wise symmetric signatures in the theory of matchgate computations. The main proof fundamental question in computational complexity theory is what di#erentiate between polynomial time

  1. Geometric morphometrics of corolla shape: dissecting components of symmetric and asymmetric variation in Erysimum

    E-print Network

    Klingenberg, Christian Peter

    Methods Geometric morphometrics of corolla shape: dissecting components of symmetric and asymmetric morphometrics, Procrustes fit, symmetry. Summary Symmetry isan important feature of floral structure, and floral symmetries are diverse and often complex. We use a new morphometric approach for analysing shapes

  2. STEIN EXTENSIONS OF RIEMANN SYMMETRIC SPACES AND DUALITIES OF ORBITS ON FLAG MANIFOLDS

    E-print Network

    STEIN EXTENSIONS OF RIEMANN SYMMETRIC SPACES AND DUALITIES OF ORBITS ON FLAG-orbits S and GR-orbits S0 on a complex flag manifold are in one-to-one correspondence by the condition compact subgroup K of GR. Let X = GC=P be a flag manifold of GC where P is an arbitrary parabolic

  3. Symmetric informationally complete measurements of arbitrary rank

    Microsoft Academic Search

    D. M. Appleby

    2007-01-01

    There has been much interest in so-called SIC-POVMs, i.e., rank 1 symmetric informationally complete positive operator valued\\u000a measures. In this paper we discuss the larger class of POVMs that are symmetric and informationally complete, but not necessarily\\u000a rank 1. This class of POVMs is of some independent interest. In particular it includes a POVM that is closely related to the

  4. Symmetric Key Structural Residues in Symmetric Proteins with Beta-Trefoil Fold

    Microsoft Academic Search

    Jianhui Feng; Mingfeng Li; Yanzhao Huang; Yi Xiao; Annalisa Pastore

    2010-01-01

    To understand how symmetric structures of many proteins are formed from asymmetric sequences, the proteins with two repeated beta-trefoil domains in Plant Cytotoxin B-chain family and all presently known beta-trefoil proteins are analyzed by structure-based multi-sequence alignments. The results show that all these proteins have similar key structural residues that are distributed symmetrically in their structures. These symmetric key structural

  5. On exact quantum query complexity

    E-print Network

    Montanaro, Ashley; Mitchison, Graeme

    2011-01-01

    We present several families of total boolean functions which have exact quantum query complexity which is a constant multiple (between 1/2 and 2/3) of their classical query complexity, and show that optimal quantum algorithms for these functions cannot be obtained by simply computing parities of pairs of bits. We also characterise the model of nonadaptive exact quantum query complexity in terms of coding theory and completely characterise the query complexity of symmetric boolean functions in this context. These results were originally inspired by numerically solving the semidefinite programs characterising quantum query complexity for small problem sizes. We include numerical results giving the optimal success probabilities achievable by quantum algorithms computing all boolean functions on up to 4 bits, and all symmetric boolean functions on up to 6 bits.

  6. Linear Filters

    NSDL National Science Digital Library

    Holden, Joshua

    Created by Joshua Holden for the Connected Curriculum Project, the purpose of this module is to explore a common application of difference equations and linear algebra in electrical engineering and signal processing. The is part of a larger collection of modules hosted by Duke University.

  7. Linear Equations

    NSDL National Science Digital Library

    2004-01-01

    This narrated demonstration introduces students to linear equations with one variable, their visual representation, and how to solve them. After the clear instructions, students are allowed to test what they've learned by solving two equations on their own. The lesson is concluded with a review of the objective and summary of the key points.

  8. Artificial conditions for the linear elasticity equations V. Bonnaillie-Noel

    E-print Network

    Paris-Sud XI, Université de

    .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 IRMAR - UMR6625, ENS Cachan Bretagne, Univ. Rennes 1, CNRS, UEB, av Robert Schuman, 35170 Bruz for a linear isotropic material with Hooke's law H. Recall that for any symmetric matrix e, H is defined by He

  9. Artificial conditions for the linear elasticity equations V. Bonnaillie-Noel

    E-print Network

    Paris-Sud XI, Université de

    of elasticity for a linear isotropic material with Hooke's law H. Recall that for any symmetric matrix e, H, Univ. Rennes 1, CNRS, UEB, av. Robert Schuman, 35170 Bruz, France, bonnaillie@math.cnrs.fr LMAP - UMR

  10. Advances in Interior Point Methods for Large-Scale Linear Programming 

    E-print Network

    Colombo, Marco

    2007-01-01

    This research studies two computational techniques that improve the practical performance of existing implementations of interior point methods for linear programming. Both are based on the concept of symmetric neighbourhood ...

  11. Symmetrical waveform generation based on temporal pulse shaping using

    E-print Network

    Yao, Jianping

    Symmetrical waveform generation based on temporal pulse shaping using amplitude-only modulator H. Chi and J. Yao Symmetrical waveform generation based on temporal pulse shaping using only an amplitude transform of a real and symmetrical waveform is still real and symmetrical. There- fore, it is possible

  12. On the Algebraic Immunity of Symmetric Boolean Functions

    Microsoft Academic Search

    An Braeken; Bart Preneel

    2005-01-01

    In this paper, we analyse the algebraic immunity of symmetric Boolean functions. We identify a set of lowest degree annihilators for symmetric functions and propose an ecient algorithm for computing the algebraic immunity of a symmetric function. The existence of several symmetric functions with maximum algebraic immunity is proven. In this way, a new class of function which have good

  13. Linear stability analysis of dynamical quadratic gravity

    NASA Astrophysics Data System (ADS)

    Ayzenberg, Dimitry; Yagi, Kent; Yunes, Nicolás

    2014-02-01

    We study the linear stability of dynamical, quadratic gravity, focusing on two particular subclasses (the even-parity sector, exemplified by Einstein-Dilaton-Gauss-Bonnet gravity, and the odd-parity sector, exemplified by dynamical Chern-Simons modified gravity) in the high-frequency, geometric optics approximation. This analysis is carried out by studying gravitational and scalar modes propagating on spherically symmetric and axially symmetric, vacuum solutions of the theory and finding the associated dispersion relations. These relations are solved in two separate cases (the scalar regime and the gravitational wave regime, defined by requiring the ratio of the amplitude of the perturbations to be much greater or smaller than unity) and found in both cases to not lead to exponential growth of the propagating modes, suggesting linearly stability. The modes are found to propagate at subluminal and superluminal speeds, depending on the propagating modes' direction relative to the background geometry, just as in dynamical Chern-Simons gravity.

  14. Tolerantly linear separability of Boolean functions and its numbering

    Microsoft Academic Search

    Zhang Junying; Xu Jin

    1996-01-01

    Linear and non-linear separability of Boolean functions are difficult problems in feedforward neural networks. Only linear separability of Boolean functions with the number of variables n<7 had been discussed before. In this paper, a tolerantly linear-separable complexity of Boolean functions is defined to simplify discussions and optimize solutions. An approach of numbering Boolean functions whose tolerantly linear-separable complexity is c

  15. A modified direct preconditioner for indefinite symmetric Toeplitz systems

    SciTech Connect

    Concus, P. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Mathematics; Saylor, P. [Illinois Univ., Urbana, IL (United States). Dept. of Computer Science

    1992-11-01

    A modification is presented of the classical O(n{sup 2}) algorithm of Trench for the direct solution of Toeplitz systems of equations. The Trench algorithm can be guaranteed to be stable only for matrices that are (symmetric) positive definite; it is generally unstable otherwise. The modification permits extension of the algorithm to compute an approximate inverse in the indefinite symmetric case, for which the unmodified algorithm breaks down when principal submatrices are singular. As a preconditioner, this approximate inverse has an advantage that only matrix-vector multiplications are required for the solution of a linear system, without forward and backward solves. The approximate inverse so obtained can be sufficiently accurate, moreover, that, when it is used as a preconditioner for the applications investigated, subsequent iteration may not even be necessary. Numerical results are given for several test matrices. The perturbation to the original matrix that defines the modification is related to a perturbation in a quantity generated in the Trench algorithm; the associated stability of the Trench algorithm is discussed.

  16. A modified direct preconditioner for indefinite symmetric Toeplitz systems

    SciTech Connect

    Concus, P. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Mathematics); Saylor, P. (Illinois Univ., Urbana, IL (United States). Dept. of Computer Science)

    1992-11-01

    A modification is presented of the classical O(n[sup 2]) algorithm of Trench for the direct solution of Toeplitz systems of equations. The Trench algorithm can be guaranteed to be stable only for matrices that are (symmetric) positive definite; it is generally unstable otherwise. The modification permits extension of the algorithm to compute an approximate inverse in the indefinite symmetric case, for which the unmodified algorithm breaks down when principal submatrices are singular. As a preconditioner, this approximate inverse has an advantage that only matrix-vector multiplications are required for the solution of a linear system, without forward and backward solves. The approximate inverse so obtained can be sufficiently accurate, moreover, that, when it is used as a preconditioner for the applications investigated, subsequent iteration may not even be necessary. Numerical results are given for several test matrices. The perturbation to the original matrix that defines the modification is related to a perturbation in a quantity generated in the Trench algorithm; the associated stability of the Trench algorithm is discussed.

  17. Honors question 3: Complex numbers (revisited). Arithmetic of complex numbers

    E-print Network

    Leininger, Christopher J.

    Honors question 3: Complex numbers (revisited). Arithmetic of complex numbers Recall that the complex numbers are formally defined as C = {a + bi} where a and b can be any real numbers and i is treated as a variable (so we can identify the complex numbers with the set of linear polynomials with real

  18. Local conservation laws in nonlinear sigma models based on symmetric spaces

    SciTech Connect

    Snyder, M.A.

    1982-01-01

    The formalism of a class of two-dimensional field theories known as nonlinear sigma models based on a symmetric space is reviewed, and the projective representation of such a symmetric space is used to find a natural geometric interpretation for the Riccati-like equations, and the consequent infinity of local conservation laws, for these models. The inverse scattering method, which has been used to great effect in the search for exact solutions to certain nonlinear partial differential equations in two variables is reviewed. These general methods are illustrated by applying them to the Korteweg-de Vries equation. After a short mathematical digression on symmetric spaces, the inverse scattering formalism is developed for nonlinear sigma models in which the fundamental field takes values in a symmetric space G/H, where G is the global invariance group of the model, and H is a subset of G is the hidden local invariance group. The isospectral pair of the inverse scattering method is interpreted as expressing the infinitesimal linear action of the group G on itself. On the other hand, the group G can be taken to act nonlinear on one of its associated symmetric spaces G/H. This nonlinear action is taken to be infinitesimal. A pair of Riccati-like equations is found. A natural geometric interpretation for the Riccati equations which in the literature appear ex nihilo is found.

  19. Elements of Cryptography.Elements of Cryptography. Symmetric Encryption.Symmetric Encryption.

    E-print Network

    Fisher, Michael

    COMP 522 Elements of Cryptography.Elements of Cryptography. Symmetric Encryption.Symmetric Encryption. NSE, sections 2.1-2.2 WSPC, chapter 3 COMP 522 Cryptography · Cryptography is a collection of mathematical techniques for protecting information; · Most important technique is encryption/decryption; · We

  20. Symmetric and Anti-Symmetric Lamb Waves in a Two-Dimensional Phononic Crystal Plate

    NASA Astrophysics Data System (ADS)

    Li, Yong; Hou, Zhi-Lin; Fu, Xiu-Jun; Badreddine, M. Assouar

    2010-07-01

    It is well known that Lamb waves in a plate with a mirror plane can be separated into two uncoupled sets: symmetric and anti-symmetric modes. Based on this property, we present a revised plane wave expansion method (PWE) to calculate the band structure of a phononic crystal (PC) plate with a mirror plane. The developed PWE method can be used to calculate the band structure of symmetric and anti-symmetric modes separately, by which the depending relationship between the partial acoustic band gap (PABG), which belongs to the symmetric and anti-symmetric modes alternatively, and the position of the scatterers can be determined. As an example of its application, the band structure of the Lamb modes in a two-dimensional PC plate with two layers of void circular inclusions is investigated. The results show that the band structure for the symmetric and anti-symmetric modes can be changed by the position of the scatterers drastically, and larger PABGs will be opened when the scatterers are inserted into the area of the plate, where the elastic potential energy is concentrated.

  1. Unmagnetized diffusion for azimuthally symmetric wave and particle distributions

    NASA Technical Reports Server (NTRS)

    Dusenbery, P. B.; Lyons, L. R.

    1988-01-01

    The quasi-linear diffusion of particles from resonant interactions with a spectrum of electrostatic waves is investigated theoretically, extending results obtained for no magnetic field and for strong magnetic fields to cases where the ambient magnetic field which organizes azimuthally symmetric wave and particle distributions does not have to be taken into consideration in evaluating the local interaction. The derivation of the governing equations is explained, and numerical results are presented in extensive graphs and characterized in detail. Slow-mode ion-acoustic waves are shown to be unstable under the plasma conditions studied, and the dependence of resonant-ion diffusion rates with pitch angle, speed, and the distribution of wave energy in wavenumber space is explored. The implications of the present findings for theoretical models of the earth bow shock and plasma-sheet boundary layer are indicated.

  2. Symmetric and asymmetric charge transport in interacting asymmetric quantum impurities

    NASA Astrophysics Data System (ADS)

    Roy, Dibyendu

    2010-02-01

    We study steady-state charge transfer across an interacting resonance-level model connected asymmetrically to two leads. For a linear energy dispersion relation of the leads, we calculate current-voltage characteristics of the model exactly employing the scattering Bethe ansatz of Mehta-Andrei and find symmetric transport showing the absence of diode effect. Next we study a lattice version of this model with a nonlinear dispersion for the leads using the Lippmann-Schwinger scattering theory. We find that the inclusion of nonlinearity in the leads’ dispersion causes rectification for asymmetric junctions but does not rectify for asymmetric interactions and perfect junctions. The model in the latter case can be mapped into a model of a single noninteracting electron in higher dimensions.

  3. Symmetric nonnegative matrix factorization: algorithms and applications to probabilistic clustering.

    PubMed

    He, Zhaoshui; Xie, Shengli; Zdunek, Rafal; Zhou, Guoxu; Cichocki, Andrzej

    2011-12-01

    Nonnegative matrix factorization (NMF) is an unsupervised learning method useful in various applications including image processing and semantic analysis of documents. This paper focuses on symmetric NMF (SNMF), which is a special case of NMF decomposition. Three parallel multiplicative update algorithms using level 3 basic linear algebra subprograms directly are developed for this problem. First, by minimizing the Euclidean distance, a multiplicative update algorithm is proposed, and its convergence under mild conditions is proved. Based on it, we further propose another two fast parallel methods: ?-SNMF and ? -SNMF algorithms. All of them are easy to implement. These algorithms are applied to probabilistic clustering. We demonstrate their effectiveness for facial image clustering, document categorization, and pattern clustering in gene expression. PMID:22042156

  4. Linear baroclinic instability in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Barnes, J. R.

    1984-05-01

    A spherical quasi-geostrophic model is used in an examination of linear baroclinic instability in such zonal-mean flows as those of the Martian atmosphere in winter, under both relatively nondusty and very dusty conditions. These zonal flows, which possess both vertical and meridional shear, are characterized by baroclinically unstable modes whose growth rates and phase speeds are generally consistent with available observations. The structures of the spherical modes are similar to those obtained for terrestrial zonal flows, if similar zonal wavelengths are compared. Zonally symmetric topography, like that of Mars' northern hemisphere, reduces linear growth rates without changing the most unstable scale. It also increases phase speeds.

  5. A Berger type normal holonomy theorem for complex submanifolds

    Microsoft Academic Search

    Sergio Console; Antonio J. Di Scala; Carlos Olmos

    2008-01-01

    We prove a Berger type theorem for the normal holonomy group (i.e., the holonomy group of the normal connection) of a full complete complex submanifold of the complex projective space. Namely, if the normal holonomy does not act transitively, then the submanifold is the complex orbit, in the complex projective space, of the isotropy representation of an irreducible Hermitian symmetric

  6. Linear Dependence and Linear Independence

    E-print Network

    PRETEX (Halifax NS) #1 1054 1999 Mar 05 10:59:16

    2010-02-12

    Feb 16, 2007 ... (7, 2, 5). (3,2, 1). (3,2, 0). (1, 1, 0). (1, 1, 1). (7, 2, 0) v3. 4v1 v2 v1 v2 ..... Corollary 4.5.12 is actually true even if the set of vectors in question is .... The set of functions {f1,f2,...,fk} is linearly independent on an interval I if and.

  7. CAST: Contraction Algorithm for Symmetric Tensors

    SciTech Connect

    Rajbhandari, Samyam; NIkam, Akshay; Lai, Pai-Wei; Stock, Kevin; Krishnamoorthy, Sriram; Sadayappan, Ponnuswamy

    2014-09-22

    Tensor contractions represent the most compute-intensive core kernels in ab initio computational quantum chemistry and nuclear physics. Symmetries in these tensor contractions makes them difficult to load balance and scale to large distributed systems. In this paper, we develop an efficient and scalable algorithm to contract symmetric tensors. We introduce a novel approach that avoids data redistribution in contracting symmetric tensors while also avoiding redundant storage and maintaining load balance. We present experimental results on two parallel supercomputers for several symmetric contractions that appear in the CCSD quantum chemistry method. We also present a novel approach to tensor redistribution that can take advantage of parallel hyperplanes when the initial distribution has replicated dimensions, and use collective broadcast when the final distribution has replicated dimensions, making the algorithm very efficient.

  8. Spherically Symmetric Thick Branes Cosmological Evolution

    E-print Network

    Bernardini, Alex E; da Rocha, Roldao

    2014-01-01

    Spherically symmetric time-dependent solutions for the 5D system of a scalar field canonically coupled to gravity are obtained and identified as an extension of recent results obtained by Ahmed, Grzadkowskia and Wudkab. The corresponding cosmology of models with regularized branes generated by such a 5D scalar field scenario is also investigated. It has been shown that the anisotropic evolution of the warp factor and consequently the Hubble like parameter are both driven by the radial coordinate on the brane, which leads to an emergent thick brane-world scenario with spherically symmetric time dependent warp factor. Meanwhile, the separability of variables depending on fifth dimension, y, which is exhibited by the equations of motion, allows one to recover the extra dimensional profiles obtained in the literature, namely the extra dimensional part of the scale (warp) factor and the scalar field dependence on y. Therefore, our results are mainly concerned with the time dependence of a spherically symmetric war...

  9. Cotton-Type and Joint Invariants for Linear Elliptic Systems

    PubMed Central

    Aslam, A.; Mahomed, F. M.

    2013-01-01

    Cotton-type invariants for a subclass of a system of two linear elliptic equations, obtainable from a complex base linear elliptic equation, are derived both by spliting of the corresponding complex Cotton invariants of the base complex equation and from the Laplace-type invariants of the system of linear hyperbolic equations equivalent to the system of linear elliptic equations via linear complex transformations of the independent variables. It is shown that Cotton-type invariants derived from these two approaches are identical. Furthermore, Cotton-type and joint invariants for a general system of two linear elliptic equations are also obtained from the Laplace-type and joint invariants for a system of two linear hyperbolic equations equivalent to the system of linear elliptic equations by complex changes of the independent variables. Examples are presented to illustrate the results. PMID:24453871

  10. SYMMETRIC INTERIOR PENALTY DG METHODS FOR THE COMPRESSIBLE NAVIER-STOKES EQUATIONS I: METHOD FORMULATION

    Microsoft Academic Search

    RALF HARTMANN; PAUL HOUSTON

    2006-01-01

    In this article we consider the development of discontinuous Galerkin finite element methods for the numerical approximation of the compressible Navier-Stokes equations. For the discretization of the leading order terms, we propose employing the generalization of the symmetric version of the interior penalty method, originally developed for the numerical approximation of linear self-adjoint second-order elliptic partial differential equations. In order

  11. Full and reduced model solutions of unsteady axi-symmetric ice sheet flow over a flat bed

    Microsoft Academic Search

    K. A. Cliffe; L. W. Morland

    2004-01-01

    A finite element algorithm is presented for the solution of the unsteady free-surface problem governed by the full, axi-symmetric, slow, linearly-viscous fluid flow equations for an isothermal ice sheet on a flat bed. A class of linearly viscous Reduced Model, Shallow Ice Approximation, exact solutions is also constructed, for which the relative error is of order of the very small

  12. The Axially Symmetric One-Monopole

    SciTech Connect

    Wong, K.-M.; Teh, Rosy [School of Physics, Universiti Sains Malaysia, 11800 USM Penang (Malaysia)

    2009-07-07

    We present new classical generalized one-monopole solution of the SU(2) Yang-Mills-Higgs theory with the Higgs field in the adjoint representation. We show that this solution with theta-winding number m = 1 and phi-winding number n = 1 is an axially symmetric generalization of the 't Hooft-Polyakov one-monopole. We construct this axially symmetric one-monopole solution by generalizing the large distance asymptotic solutions of the 't Hooft-Polyakov one-monopole to the Jacobi elliptic functions and solving the second order equations of motion numerically when the Higgs potential is vanishing. This solution is a non-BPS solution.

  13. All-optical symmetric ternary logic gate

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay

    2010-09-01

    Symmetric ternary number (radix=3) has three logical states (1¯, 0, 1). It is very much useful in carry free arithmetical operation. Beside this, the logical operation using this type of number system is also effective in high speed computation and communication in multi-valued logic. In this literature all-optical circuits for three basic symmetrical ternary logical operations (inversion, MIN and MAX) are proposed and described. Numerical simulation verifies the theoretical model. In this present scheme the different ternary logical states are represented by different polarized state of light. Terahertz optical asymmetric demultiplexer (TOAD) based interferometric switch has been used categorically in this manuscript.

  14. Linear Clouds

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03667 Linear Clouds

    These clouds are located near the edge of the south polar region. The cloud tops are the puffy white features in the bottom half of the image.

    Image information: VIS instrument. Latitude -80.1N, Longitude 52.1E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. On generalized symmetric powers and a generalization of Kolmogorov-Gelfand-Buchstaber-Rees theory

    E-print Network

    H. M. Khudaverdian; Th. Th. Voronov

    2007-03-05

    The classical Kolmogorov-Gelfand theorem gives an embedding of a (compact Hausdorff) topological space X into the linear space of all linear functionals C(X)^* on the algebra of continuous functions C(X). The image is specified by algebraic equations: f(ab)=f(a)f(b) for all functions a, b on X; that is, the image consists of all algebra homomorphisms of C(X) to numbers. Buchstaber and Rees have found that not only X, but all symmetric powers of X can be embedded into the space C(X)^*. The embedding is again given by algebraic equations, but more complicated. Algebra homomorphisms are replaced by the so-called "n-homomorphisms", the notion that can be traced back to Frobenius, but which explicitly appeared in Buchstaber and Rees's works on multivalued groups. We give a further natural generalization of Kolmogorov-Gelfand-Buchstaber-Rees theory. Symmetric powers of a space X or of an algebra A are replaced by certain "generalized symmetric powers" Sym^{p|q}(X) and S^{p|q}A, which we introduce, and n-homomorphisms, by the new notion of "p|q-homomorphisms". Important tool of our study is a certain "characteristic function" R(f,a,z), which we introduce for an arbitrary linear map of algebras f, and whose functional properties with respect to the variable z reflect algebraic properties of the map f.

  16. Applications of the method of complex characteristics

    NASA Astrophysics Data System (ADS)

    Chen, Connie Kangyan

    1997-11-01

    Computational fluid dynamics has proved to be an exceptionally effective method for analyzing flow problems. In particular, the method of complex characteristics can be used to analyze transonic flows in two-dimensions. It has served to design supercritical wing sections that reduce the wave drag significantly on modern aircraft, and it is an excellent tool for the numerical construction of shockless airfoils. The present research is devoted to applications of the method of complex characteristics. First, the method has been developed as a parallel algorithm to solve the Dirichlet problem for a linear elliptic partial differential equation with analytic coefficients in the plane. Numerical experiments have been performed to establish that this technique works well as a parallel algorithm on a cluster of computers. A second phase of the research has led to a robust engineering code for the design of shockless airfoils, either isolated or in cascade, that can be run on either large or small computers. The code has been applied to study uniqueness in transonic flow problems. It has led to the discovery of an exceptionally thick and smooth symmetric airfoil with several solutions so that a flow with lift is produced at zero angle of attack.

  17. Higher Dimensional Spherically Symmetric Gravitational Collapse

    NASA Astrophysics Data System (ADS)

    Ahmad, Zahid; Haseeb, Abdul

    2014-04-01

    In this paper, the gravitational collapse of type I matter has been investigated in the context of higher dimensional spherically symmetric spacetime. The equation of state with b>0 is assumed. The effects of more than four dimensions on the nature of the singularity are being discussed.

  18. ccsd00002799, KILLING FORMS ON SYMMETRIC SPACES

    E-print Network

    ccsd­00002799, version 1 ­ 7 Sep 2004 KILLING FORMS ON SYMMETRIC SPACES FLORIN BELGUN, ANDREI MOROIANU AND UWE SEMMELMANN Abstract. Killing forms on Riemannian manifolds are di#11;erential forms whose space carries a non{parallel Killing p{form (p #21; 2) if and only if it isometric to a Riemannian

  19. Symmetrical parametrizations of the lepton mixing matrix

    SciTech Connect

    Rodejohann, W. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, 69029 Heidelberg (Germany); Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apt 22085, E-46071 Valencia (Spain)

    2011-10-01

    Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases. It is also ideal for parametrizing scenarios with light sterile neutrinos.

  20. Symmetric Projections of the Entropy Region

    E-print Network

    Cai, Xinyi

    2014-11-19

    OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Thesis... Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. ON THE AVERAGE ENTROPY REGIONS . . . . . . . . . . . . . . . . . 6 2.1 Group-Induced Symmetric Projections . . . . . . . . . . . . . . . . . 7 2.2 The Total-Average Projection...

  1. HOMOGENEOUS EINSTEINWEYL STRUCTURES ON SYMMETRIC SPACES

    E-print Network

    Kerr, Megan M.

    is Date: August 18, 1997. 1 #12;2 MEGAN M. KERR the Gauduchon metric. Hence we will assume from nowHOMOGENEOUS EINSTEIN­WEYL STRUCTURES ON SYMMETRIC SPACES MEGAN M. KERR Abstract. In this paper we of the metric ( is a function on M). Three-dimensional compact Einstein­Weyl spaces have been completely

  2. Vacuum calculations in azimuthally symmetric geometry

    Microsoft Academic Search

    M. S. Chance

    1997-01-01

    A robustly accurate and effective method is presented to solve Laplace{close_quote}s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conductors. These conductors can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various magnetohydrodynamic

  3. Vacuum calculations in azimuthally symmetric geometry

    Microsoft Academic Search

    M. S. Chance

    1997-01-01

    A robustly accurate and effective method is presented to solve Laplace’s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conductors. These conductors can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various magnetohydrodynamic

  4. VACUUM calculation in azimuthally symmetric geometry

    Microsoft Academic Search

    1996-01-01

    A robustly accurate and effective method is presented to solve Laplace`s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conducting shells. These shells can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various

  5. Ch.19 Symmetric Encryption and Message Confidentiality

    E-print Network

    Dong, Yingfei

    1 1 Ch.19 Symmetric Encryption and Message Confidentiality · HW 9 and 10: upto this Wen · Next week: Ch.20 Public key Crypto · Conventional Encryption Principles · Conventional Encryption Algorithms: DES, AES · Cipher Block Modes of Operation: Block vs. stream · Location of Encryption Devices · Key

  6. NonceBased Symmetric Encryption Phillip Rogaway

    E-print Network

    Rogaway, Phillip

    Nonce­Based Symmetric Encryption Phillip Rogaway Dept. of Computer Science, University encryption schemes are usually formalized so as to make the encryption operation a probabilistic or state­dependent func­ tion E of the message M and the key K: the user supplies M and K and the encryption process does

  7. Symmetric Stereo Matching for Occlusion Handling

    Microsoft Academic Search

    Jian Sun; Yin Li; Sing Bing Kang; Heung-Yeung Shum

    2005-01-01

    In this paper, we propose a symmetric stereo model to han- dle occlusion in dense two-frame stereo. Our occlusion reasoning is directly based on the visibility constraint that is more general than both ordering and uniqueness con- straints used in previous work. The visibility constraint requires occlusion in one image and disparity in the other to be consistent. We embed

  8. Unidirectional nonlinear PT-symmetric optical structures

    SciTech Connect

    Ramezani, Hamidreza [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States); Kottos, Tsampikos [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States); Max-Planck-Institute for Dynamics and Self-Organization, D-37073 Goettingen (Germany); El-Ganainy, Ramy; Christodoulides, Demetrios N. [College of Optics and Photonics-CREOL, University of Central Florida, Orlando, Florida 32816 (United States)

    2010-10-15

    We show that nonlinear optical structures involving a balanced gain-loss profile can act as unidirectional optical valves. This is made possible by exploiting the interplay between the fundamental symmetries of parity (P) and time (T), with optical nonlinear effects. This unidirectional dynamics is specifically demonstrated for the case of an integrable PT-symmetric nonlinear system.

  9. Reciprocal Symmetric and Origin of Quantum Statistics

    E-print Network

    Mushfiq Ahmad

    2007-03-21

    Boltzmann's differential equation is replaced by the corresponding reciprocal symmetric finite difference equation. Finite difference translates discreteness of energy. Boltzmann's function, then, splits into two reciprocally related functions. One of them gives Planck's radiation relation and the other one gives the corresponding Fermi-Dirac relation.

  10. Symmetrization of cyclic sigma-telluranes

    SciTech Connect

    Sadekov, I.D.; Rivkin, B.B.; Maslakov, A.G.; Minkin, V.I.

    1987-09-01

    The authors examine reactions involving cyclic sigma-telluranes. Refluxing 5,5-dichlorodibenzotellurophene with tellurium tetrachloride in o-dichlorobenzene results in symmetrization and the formation of 2,2'-bis(trichlorotelluro)diphenyl in high yield. The other compounds formed and described are polymeric ditelluride, dibenzotellurophene, and dimethyltellurium dibromide.

  11. MINIMUM POWER SYMMETRIC CONNECTIVITY PROBLEM IN

    E-print Network

    Gambardella, Luca Maria

    the probability of detection by enemy radar. In this paper, we focus on the minimum power topology problemMINIMUM POWER SYMMETRIC CONNECTIVITY PROBLEM IN WIRELESS NETWORKS: A NEW APPROACH Roberto preprocessing technique. Keywords: Wireless networks, minimum power topology, exact algorithms. 1. Introduction

  12. Stability Analysis of a Symmetrical Induction Machine

    Microsoft Academic Search

    ROBERT H. NELSON; THOMAS A. LIPO; PAUL C. KRAUSE

    1969-01-01

    A stability study of an induction machine is performed by applying the root-locus criterion to the equations which describe the behavior of the machine during small displacements about a steady-state operating point. This investigation reveals that a symmetrical induction machine may become unstable at low speeds (low frequencies) even though balanced, constant amplitude, sinusoidal voltages are applied to the stator

  13. Symmetric Projections of the Entropy Region 

    E-print Network

    Cai, Xinyi

    2014-11-19

    OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Thesis... Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. ON THE AVERAGE ENTROPY REGIONS . . . . . . . . . . . . . . . . . 6 2.1 Group-Induced Symmetric Projections . . . . . . . . . . . . . . . . . 7 2.2 The Total-Average Projection...

  14. Realizability of stationary spherically symmetric transonic accretion

    E-print Network

    Arnab K. Ray; J. K. Bhattacharjee

    2004-09-20

    The spherically symmetric stationary transonic (Bondi) flow is considered a classic example of an accretion flow. This flow, however, is along a separatrix, which is usually not physically realizable. We demonstrate, using a pedagogical example, that it is the dynamics which selects the transonic flow.

  15. Symmetric Publish/Subscribe via Constraint Publication

    E-print Network

    Symmetric Publish/Subscribe via Constraint Publication Anthony Tomasic, Charles Garrod, and Kris 15213 Abstract Current publish / subscribe systems o#er a range of expressive subscription languages for con­ straints. However, classical systems restrict the publish operation to be a single published

  16. Symmetric Publish/Subscribe via Constraint Publication

    E-print Network

    Symmetric Publish/Subscribe via Constraint Publication Anthony Tomasic, Charles Garrod, and Kris 15213 Abstract Current publish / subscribe systems offer a range of expressive subscription languages for con- straints. However, classical systems restrict the publish operation to be a single published

  17. Formation of interpolymer complexes

    Microsoft Academic Search

    Eishun Tsuchida; Yoshihito Osada; Hiroyuki Ohno

    1980-01-01

    Interpolymer complex formations of poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) with oligocations as well as poly(ethylene oxide) (PEO), and poly-(N-vinyl-2-pyrrolidone of various chain lengths were studied. For the case of complexation between PMAA and oligocations, the standard free energy change for the complexation ?G° was found to be linearly dependent on the number of interacting sites, n. The stability

  18. A fully symmetric nonlinear biorthogonal decomposition theory for random fields

    NASA Astrophysics Data System (ADS)

    Venturi, Daniele

    2011-02-01

    We present a general approach for nonlinear biorthogonal decomposition of random fields. The mathematical theory is developed based on a fully symmetric operator framework that unifies different types of expansions and allows for a simple formulation of necessary and sufficient conditions for their completeness. The key idea of the method relies on an equivalence between nonlinear mappings of Hilbert spaces and local inner products, i.e. inner products that may be functionals of the random field being decomposed. This extends previous work on the subject and allows for an effective formulation of field-dependent and field-independent representations. The proposed new methodology can be applied in many areas of mathematical physics, for stochastic low-dimensional modelling of partial differential equations and dimensionality reduction of complex nonlinear phenomena. An application to a transient stochastic heat conduction problem in a one-dimensional infinite medium is presented and discussed.

  19. Waterbomb base: a symmetric single-vertex bistable origami mechanism

    NASA Astrophysics Data System (ADS)

    Hanna, Brandon H.; Lund, Jason M.; Lang, Robert J.; Magleby, Spencer P.; Howell, Larry L.

    2014-09-01

    The origami waterbomb base is a single-vertex bistable origami mechanism that has unique properties which may prove useful in a variety of applications. It also shows promise as a test bed for smart materials and actuation because of its straightforward geometry and multiple phases of motion, ranging from simple to more complex. This study develops a quantitative understanding of the symmetric waterbomb base's kinetic behavior. This is done by completing kinematic and potential energy analyses to understand and predict bistable behavior. A physical prototype is constructed and tested to validate the results of the analyses. Finite element and virtual work analyses based on the prototype are used to explore the locations of the stable equilibrium positions and the force-deflection response. The model results are verified through comparisons to measurements on a physical prototype. The resulting models describe waterbomb base behavior and provide an engineering tool for application development.

  20. Optimal Computation of Symmetric Boolean Functions in Collocated Networks

    E-print Network

    Kowshik, Hemant

    2011-01-01

    We consider collocated wireless sensor networks, where each node has a Boolean measurement and the goal is to compute a given Boolean function of these measurements. We first consider the worst case setting and study optimal block computation strategies for computing symmetric Boolean functions. We study three classes of functions: threshold functions, delta functions and interval functions. We provide exactly optimal strategies for the first two classes, and a scaling law order-optimal strategy with optimal preconstant for interval functions. We also extend the results to the case of integer measurements and certain integer-valued functions. We use lower bounds from communication complexity theory, and provide an achievable scheme using information theoretic tools. Next, we consider the case where nodes measurements are random and drawn from independent Bernoulli distributions. We address the problem of optimal function computation so as to minimize the expected total number of bits that are transmitted. In ...

  1. UNREDUCED SYMMETRIC KKT SYSTEMS ARISING FROM ...

    E-print Network

    2014-07-01

    Jul 1, 2014 ... constituted by the solution of a structured algebraic linear system. Therefore, much ef- ...... stcqp1 b with K3,reg, the use of preconditioned iterative solvers speeds the solution of the linear algebra ..... block-angular problems.

  2. Computed tomography of cylindrically symmetric object by use of digital holography

    NASA Astrophysics Data System (ADS)

    Pan, Zhelang; Li, Shiping; Zhong, Jingang

    2013-04-01

    Digital holographic tomography, a computed tomography by use of digital holography, has a huge potential for three-dimensional imaging of weakly-diffracting phase objects. But the need of multiple angles of illumination weakened imaging capability of dynamic objects. For cylindrically symmetric object, we can use complex amplitude data of single hologram under zero incidence angles to replace the other complex amplitude data under different incidence angles. Therefore, it is possible to achieve the dynamic imaging of cylindrically symmetric objects. The digital holographic tomography can provide a way for the dynamic imaging of phase-type objects having a cylindrically symmetric structure. We report an experimental example of the capillary tube having a cylindrically symmetric structure. Tomography of the capillary tube is performed by filtered back-projection algorithm and Fourier diffraction algorithm respectively to reconstruct the 3-D map of refractive index. Experimental results show that, comparing with the filtered back-projection reconstruction, diffraction tomography based on the Rytov approximation better respects the dimensions of the capillary tube.

  3. An Approximate Solution and Master Curves for Buckling of Symmetrically Laminated Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    2013-01-01

    Nondimensional linear-bifurcation buckling equations for balanced, symmetrically laminated cylinders with negligible shell-wall anisotropies and subjected to uniform axial compression loads are presented. These equations are solved exactly for the practical case of simply supported ends. Nondimensional quantities are used to characterize the buckling behavior that consist of a stiffness-weighted length-to-radius parameter, a stiffness-weighted shell-thinness parameter, a shell-wall nonhomogeneity parameter, two orthotropy parameters, and a nondimensional buckling load. Ranges for the nondimensional parameters are established that encompass a wide range of laminated-wall constructions and numerous generic plots of nondimensional buckling load versus a stiffness-weighted length-to-radius ratio are presented for various combinations of the other parameters. These plots are expected to include many practical cases of interest to designers. Additionally, these plots show how the parameter values affect the distribution and size of the festoons forming each response curve and how they affect the attenuation of each response curve to the corresponding solution for an infinitely long cylinder. To aid in preliminary design studies, approximate formulas for the nondimensional buckling load are derived, and validated against the corresponding exact solution, that give the attenuated buckling response of an infinitely long cylinder in terms of the nondimensional parameters presented herein. A relatively small number of "master curves" are identified that give a nondimensional measure of the buckling load of an infinitely long cylinder as a function of the orthotropy and wall inhomogeneity parameters. These curves reduce greatly the complexity of the design-variable space as compared to representations that use dimensional quantities as design variables. As a result of their inherent simplicity, these master curves are anticipated to be useful in the ongoing development of buckling-design technology.

  4. Linear theory for optimal control of molecular wave packets

    Microsoft Academic Search

    Jianshu Cao; Kent R. Wilson

    1997-01-01

    A linear theory for optimizing optical fields to achieve a molecular configuration at a chosen time is formulated with an emphasis on the symmetric transformation between time domain and space domain representations. Based on two different measures of control, the yield and achievement functions, two parallel but distinct optimization schemes are derived in a unified algebraic format. Connections are then

  5. Tunneling control using classical non-linear oscillator

    SciTech Connect

    Kar, Susmita [Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata -700032 (India); Bhattacharyya, S. P., E-mail: pcspb@chem.iitb.ac.in [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai- 400076 (India)

    2014-04-24

    A quantum particle is placed in symmetric double well potential which is coupled to a classical non-linear oscillator via a coupling function. With different spatial symmetry of the coupling and under various controlling fashions, the tunneling of the quantum particle can be enhanced or suppressed, or totally destroyed.

  6. The nervous system of Microstomum lineare (Turbellaria, Macrostomida)

    Microsoft Academic Search

    Maria Reuter; Abo Akademi

    1981-01-01

    The ultrastructure of release sites of neurochemical messenger substances in the microturbellarian Microstomum lineare was examined. Aminergic neurites form conventional synapses and synapse-like structures (SLS). Variants of true synapses include: “single” synapses with symmetric pre- and postsynaptic densities, “shared” synapses, i.e., contacts between 1 pre- and 2 postsynaptic fibres, en passant synapses between parallel axonal membranes, and synapses without thickenings

  7. Dissipative trapped-electron instability in quasihelically symmetric stellarators

    SciTech Connect

    Rafiq, T.; Hegna, C.C. [Engineering Physics Department, University of Wisconsin, Madison, Wisconsin 53706-1609 (United States)

    2006-05-15

    The linear electrostatic dissipative trapped-electron mode is investigated in a quasihelically symmetric (QHS) stellarator and a configuration whose symmetry is spoiled by the addition of a mirror contribution to the magnetic spectrum. The effect of the trapped electrons is accounted for using the drift kinetic equation with an energy-dependent Krook collision operator and an effective collision frequency giving the rate of detrapping. The ballooning mode formalism and Wentzel-Kramers-Brillouin type boundary conditions are used to solve an eigenvalue problem for a drift wave equation with nearly adiabatic electrons in a fully three-dimensional magnetohydrodynamic equilibria. The trapped-electron growth rate is calculated using a perturbative approach. Multiple classes of helically localized and toroidally localized eigenfunctions in the ballooning space are calculated. The results of the QHS configuration is compared and contrasted with the results of the mirror configuration. The helically trapped modes are found to be most destabilizing. In both configurations the magnitude of the linear growth rates are comparable, crudely indicating the same level of anomalous flux as has also been observed in the edge region of experiments.

  8. Universal Linear Optics

    E-print Network

    Jacques Carolan; Chris Harrold; Chris Sparrow; Enrique Martín-López; Nicholas J. Russell; Joshua W. Silverstone; Peter J. Shadbolt; Nobuyuki Matsuda; Manabu Oguma; Mikitaka Itoh; Graham D. Marshall; Mark G. Thompson; Jonathan C. F. Matthews; Toshikazu Hashimoto; Jeremy L. O'Brien; Anthony Laing

    2015-05-05

    Linear optics underpins tests of fundamental quantum mechanics and computer science, as well as quantum technologies. Here we experimentally demonstrate the longstanding goal of a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons and their measurement with a 12 single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with average fidelity 0.999 $\\pm$ 0.001. Our system is capable of switching between these and any other linear optical protocol in seconds. These results point the way to applications across fundamental science and quantum technologies.

  9. Linear Thermodynamics of Rodlike DNA Filtration

    E-print Network

    Li, Zirui

    Linear thermodynamics transportation theory is employed to study filtration of rodlike DNA molecules. Using the repeated nanoarray consisting of alternate deep and shallow regions, it is demonstrated that the complex ...

  10. A NOTE ON THE COMPOSITION PRODUCT OF SYMMETRIC MICHAEL CHING

    E-print Network

    Ching, Michael

    sequences, it has enough structure, namely that of a `normal oplax' monoidal product, to be able to defineA NOTE ON THE COMPOSITION PRODUCT OF SYMMETRIC SEQUENCES MICHAEL CHING Abstract. We consider the composition product of symmetric sequences in the case where the underlying symmetric monoidal structure does

  11. Computational Soundness for Key Exchange Protocols with Symmetric Encryption

    E-print Network

    Computational Soundness for Key Exchange Protocols with Symmetric Encryption Ralf K¨usters and Max, for the case of active adversaries and protocols that use symmetric encryption computational soundness has exchange protocols with symmetric encryption, along the lines of a paper by Canetti and Herzog on protocols

  12. Invertible Symmetric 3 3 Binary Matrices and GQ(2, 4)

    E-print Network

    Paris-Sud XI, Université de

    Invertible Symmetric 3 × 3 Binary Matrices and GQ(2, 4) Andrea Blunck,1 P´eter L´evay,2 Metod of 27 (disregarding the identity) invertible symmetric 3 × 3 matrices over GF(2) and the points of invertible symmetric 3 × 3 matrices over the field GF(2) has 28 elements. The elements different from

  13. A Uniform Description of Riemannian Symmetric Spaces as Grassmannians Using

    E-print Network

    Leung, Naichung Conan

    A Uniform Description of Riemannian Symmetric Spaces as Grassmannians Using Magic Square HUANG;Symmetric Spaces as Grassmannians Using Magic Square 1 Abstract In this thesis we introduce and study the (i description of all symmetric spaces. This is analogous to Tits magic square description for simple Lie

  14. Not so Complex: Iteration in the Complex Plane

    ERIC Educational Resources Information Center

    O'Dell, Robin S.

    2014-01-01

    The simple process of iteration can produce complex and beautiful figures. In this article, Robin O'Dell presents a set of tasks requiring students to use the geometric interpretation of complex number multiplication to construct linear iteration rules. When the outputs are plotted in the complex plane, the graphs trace pleasing designs…

  15. International Workshop on Linear Colliders 2010

    ScienceCinema

    None

    2011-10-06

    IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat  IWLC2010 is hosted by CERN

  16. Regularizing Linear Discriminant Analysis for Speech Recognition

    E-print Network

    Erdogan, Hakan

    Regularizing Linear Discriminant Analysis for Speech Recognition Hakan Erdogan Faculty in a pattern recognition system is the feature extractor. Feature extraction is an important step for speech recognition since the time-domain speech signal is highly variable, thus complex linear and nonlinear

  17. Energy-momentum distribution of a general plane symmetric spacetime in metric f(R) gravity

    E-print Network

    Morteza Yavari

    2014-06-13

    In this paper, the exact vacuum solution of a general plane symmetric spacetime is investigated in metric f(R) gravity with the assumption of constant Ricci scalar. For this solution, we have studied the generalized Landau-Lifshitz energy-momentum complex in this theory to determine the energy distribution expressions for some specific f(R) models. Also, we show that these models satisfy the constant curvature condition.

  18. Design and Synthesis of C2-Symmetric N-Heterocyclic Carbene Precursors and Metal Carbenoids

    PubMed Central

    Albright, Abigail; Eddings, Daniel; Black, Regina; Welch, Christopher J.; Gerasimchuk, Nikolay N.; Gawley, Robert E.

    2011-01-01

    Chiral, C2-symmetric imidazolium and imidazolinium ions, as well as the corresponding copper or silver bound carbenoids, have been prepared. Structural study of these compounds by X-ray crystallography reveals a chiral pocket that surrounds the putative carbene site or the metal-carbene bond, at carbon 2, in three of the four ligands prepared. Preliminary investigation into the application of these complexes has shown one of them to be highly enantioselective in the hydrosilylation of acetophenone. PMID:21823580

  19. The atness theorem for non-symmetric convex bodies via the local theory of Banach

    E-print Network

    Pajor, Alain

    of that constant is relevant to the complexity of Lenstra's algorithm. Given convex body K #26; IR n denote Flt(K that if K is an n-dimensional convex body, then Flt(K) #20; Cn 2 (here and below, C, c, c 0 , c 0 etc. It was later proved by Banaszczyk (1996) that Flt(K) #20; C n(1 + log n) if K is symmetric, and that Flt(K) #20

  20. Cusped Wilson lines in symmetric representations

    E-print Network

    Correa, Diego H; Trancanelli, Diego

    2015-01-01

    We study the cusped Wilson line operators and Bremsstrahlung functions associated to particles transforming in the rank-$k$ symmetric representation of the gauge group $U(N)$ for ${\\cal N} = 4$ super Yang-Mills. We find the holographic D3-brane description for Wilson loops with internal cusps in two different limits: small cusp angle and $k\\sqrt{\\lambda}\\gg N$. This allows for a non-trivial check of a conjectured relation between the Bremsstrahlung function and the expectation value of the 1/2 BPS circular loop in the case of a representation other than the fundamental. Moreover, we observe that in the limit of $k\\gg N$, the cusped Wilson line expectation value is simply given by the exponential of the 1-loop diagram. Using group theory arguments, this eikonal exponentiation is conjectured to take place for all Wilson loop operators in symmetric representations with large $k$, independently of the contour on which they are supported.

  1. Binary switching in a ‘symmetric' potential landscape

    PubMed Central

    Roy, Kuntal; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2013-01-01

    A binary switch is the basic building block for information processing. The potential energy profile of a bistable binary switch is a ‘symmetric' double well. The traditional method of switching it from one state (one well) to the other is to tilt the profile towards the desired state. Here, we present a case, where no such tilting is necessary to switch successfully, even in the presence of thermal noise. This happens because of the built-in dynamics inside the switch itself. It differs from the general perception on binary switching that in a ‘symmetric' potential landscape, the switching probability is 50% in the presence of thermal noise. Our results, considering the complete three-dimensional potential landscape, demonstrate intriguing phenomena on binary switching mechanism. With experimentally feasible parameters, we theoretically demonstrate such intriguing possibility in electric field induced magnetization switching of a shape-anisotropic single-domain magnetostrictive nanomagnet with two stable states at room-temperature. PMID:24154561

  2. Cusped Wilson lines in symmetric representations

    E-print Network

    Diego H. Correa; Fidel I. Schaposnik Massolo; Diego Trancanelli

    2015-06-04

    We study the cusped Wilson line operators and Bremsstrahlung functions associated to particles transforming in the rank-$k$ symmetric representation of the gauge group $U(N)$ for ${\\cal N} = 4$ super Yang-Mills. We find the holographic D3-brane description for Wilson loops with internal cusps in two different limits: small cusp angle and $k\\sqrt{\\lambda}\\gg N$. This allows for a non-trivial check of a conjectured relation between the Bremsstrahlung function and the expectation value of the 1/2 BPS circular loop in the case of a representation other than the fundamental. Moreover, we observe that in the limit of $k\\gg N$, the cusped Wilson line expectation value is simply given by the exponential of the 1-loop diagram. Using group theory arguments, this eikonal exponentiation is conjectured to take place for all Wilson loop operators in symmetric representations with large $k$, independently of the contour on which they are supported.

  3. A parallel solution for the symmetric Eigenproblem

    NASA Technical Reports Server (NTRS)

    Thurston, Gaylen A.

    1987-01-01

    A completely parallel algorithm for the symmetric eigenproblem AX = Lambda BX is outlined. The algorithm is parallel in the sense that the numerical operations do not occur in a fixed sequence. Therefore, a large number of operations can be programmed to be performed concurrently on a computer with multiple central processing units. The standard symmetric eigenvalue problem AX = Lambda X has the property that the n eigenvalues of the principal submatrix of A of order n are separated by the (n-1) eignvalues of the principal submatrix of order (n-1). The separation property delineated n intervals containing one eigenvalue. Each eigenvalue and corresponding eigenvector can be computed independently. The n eigenproblem calculations can be divided among multiple processing units.

  4. Error correction and symmetrization in quantum computers

    E-print Network

    Peres, A

    1996-01-01

    Errors in quantum computers are of two kinds: sudden perturbations to isolated qubits, and slow random drifts of all the qubits. The latter may be reduced, but not eliminated, by means of symmetrization, namely by using many replicas of the computer, and forcing their joint quantum state to be completely symmetric. On the other hand, isolated errors can be corrected by quantum codewords that represent a logical qubit in a redundant way, by several physical qubits. If one of the physical qubits is perturbed, for example if it gets entangled with an unknown environment, there still is enough information encoded in the other physical qubits to restore the logical qubit, and disentangle it from the environment. The recovery procedure may consist of unitary operations, without the need of actually identifying the error.

  5. Error correction and symmetrization in quantum computers

    E-print Network

    Asher Peres

    1996-11-26

    Errors in quantum computers are of two kinds: sudden perturbations to isolated qubits, and slow random drifts of all the qubits. The latter may be reduced, but not eliminated, by means of symmetrization, namely by using many replicas of the computer, and forcing their joint quantum state to be completely symmetric. On the other hand, isolated errors can be corrected by quantum codewords that represent a logical qubit in a redundant way, by several physical qubits. If one of the physical qubits is perturbed, for example if it gets entangled with an unknown environment, there still is enough information encoded in the other physical qubits to restore the logical qubit, and disentangle it from the environment. The recovery procedure may consist of unitary operations, without the need of actually identifying the error.

  6. Multiphoton states related via linear optics

    NASA Astrophysics Data System (ADS)

    Migda?, Piotr; Rodríguez-Laguna, Javier; Oszmaniec, Micha?; Lewenstein, Maciej

    2014-06-01

    We investigate which pure states of n photons in d modes can be transformed into each other via passive linear optics, without postselection. In other words, we study the local unitary (LU) equivalence classes of symmetric many-qudit states. Writing our state as f†|?>, with f† a homogeneous polynomial in the mode creation operators, we propose two sets of LU invariants: spectral invariants, which are the eigenvalues of the operator ff†, and moments, each given by the norm of the symmetric component of a tensor power of the initial state, which can be computed as vacuum expectation values of fk(f†)k. We provide a scheme for experimental measurement of the later, as related to the postselection probability of creating state f†k|?> from k copies of f†|?>.

  7. Fitting Skyrme functionals using linear response theory

    E-print Network

    Pastore, A; Bennaceur, K; Meyer, J; Hellemans, V

    2012-01-01

    Recently, it has been recently shown that the linear response theory in symmetric nuclear matter can be used as a tool to detect finite size instabilities for different Skyrme functionals. In particular it has been shown that there is a correlation between the density at which instabilities occur in infinite matter and the instabilities in finite nuclei. In this article we present a new fitting protocol that uses this correlation to add new additional constraint in Symmetric Infinite Nuclear Matter in order to ensure the stability of finite nuclei against matter fluctuation in all spin and isospin channels. As an application, we give the parameters set for a new Skyrme functional which includes central and spin-orbit parts and which is free from instabilities by construction.

  8. Fitting Skyrme functionals using linear response theory

    E-print Network

    A. Pastore; D. Davesne; K. Bennaceur; J. Meyer; V. Hellemans

    2012-10-30

    Recently, it has been recently shown that the linear response theory in symmetric nuclear matter can be used as a tool to detect finite size instabilities for different Skyrme functionals. In particular it has been shown that there is a correlation between the density at which instabilities occur in infinite matter and the instabilities in finite nuclei. In this article we present a new fitting protocol that uses this correlation to add new additional constraint in Symmetric Infinite Nuclear Matter in order to ensure the stability of finite nuclei against matter fluctuation in all spin and isospin channels. As an application, we give the parameters set for a new Skyrme functional which includes central and spin-orbit parts and which is free from instabilities by construction.

  9. Surface-Bound Ruthenium Diimine Organometallic Complexes: Excited-State Properties

    PubMed Central

    2015-01-01

    Ruthenium complexes of the general formula [Ru(CO)(H)(L2)(L?2)][PF6] (L2 = trans-2PPh3, L? = ?2-4,4?-dicarboxybipyridine (1); L2 =trans-2Ph2PCH2CH2COOH, L?2 = bipyridine (2); L2 = Ph2PCHCHPPh2, L? = ?2-5-amino-1,10-phenanthroline (3); L2 = trans-2PPh3, L?2 = ?2-4-carboxaldehyde-4?-methylbipyridine (4)) have been shown to have longer emission lifetimes and higher quantum yields in solution compared with more symmetrical molecules such as [Ru(bpy)3][Cl]2. Compound 4 is obtained as a mixture with the corresponding acetal, 4?. These less symmetrical complexes have been covalently immobilized on the surface of silica polyamine composites, and their photophysical properties have been studied. The surface-bound complexes have been characterized by solid-state CPMAS 13C, 31P, and 29Si NMR, UV–vis, and FT-IR spectroscopies. Excited-state lifetime studies revealed that, in general, the lifetimes of the immobilized complexes are 1.4 to 8 times longer than in solution and are dependent on particle size (300–500 ?m versus 10–20 nm average diameter silica gels), polymer structure (linear poly(allylamine) versus branched poly(ethylenimine)), and the type of surface tether. One exception to this trend is the previously reported complex [Ru(bpy)2(5-amino-1,10-phenanthroline)][PF6]2 (5), where only a slight increase in lifetime is observed. Only minor changes in emission wavelength are observed for all the complexes. This opens up the possibility for enhanced heterogeneous electron transfer in photocatalytic reactions. PMID:24891753

  10. Thiolation of symmetrical and unsymmetrical diketopiperazines.

    PubMed

    Ruff, Bettina M; Zhong, Sabilla; Nieger, Martin; Bräse, Stefan

    2012-02-01

    The introduction of sulfur units into a variety of symmetrical and unsymmetrical diketopiperazines (DKPs) is described. We investigated different thiolation methods utilizing several bases and electrophilic sulfur reagents, leading to monomethylthio-, bis(methylthio)-, and epithio-DKPs. Their formation proceeded diastereoselectively, facilitating the application in total syntheses of many thiodiketopiperazine (TDKP) natural products. Furthermore, possible side reactions as well as mechanistic studies and stereochemical structural assignments of the obtained products are given. PMID:22183416

  11. Solitons in PT-symmetric nonlinear lattices

    SciTech Connect

    Abdullaev, Fatkhulla Kh.; Konotop, Vladimir V.; Zezyulin, Dmitry A. [Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Universidade de Lisboa, Avenida Professor Gama Pinto 2, P-1649-003 Lisboa (Portugal); Kartashov, Yaroslav V. [ICFO-Institut de Ciencies Fotoniques, and Universitat Politecnica de Catalunya, Mediterranean Technology Park, E-08860 Castelldefels, Barcelona (Spain)

    2011-04-15

    The existence of localized modes supported by the PT-symmetric nonlinear lattices is reported. The system considered reveals unusual properties: unlike other typical dissipative systems, it possesses families (branches) of solutions, which can be parametrized by the propagation constant; relatively narrow localized modes appear to be stable, even when the conservative nonlinear lattice potential is absent; and finally, the system supports stable multipole solutions.

  12. On the Symmetric Negabent Boolean Functions

    Microsoft Academic Search

    Sumanta Sarkar

    2009-01-01

    We study the negabent Boolean functions which are symmetric. The Boolean function which has equal absolute spectral values\\u000a under the nega-Hadamard transform is called a negabent function. For a bent function, the absolute spectral values are the\\u000a same under the Hadamard-Walsh transform. Unlike bent functions, negabent functions can exist on odd number of variables. Moreover,\\u000a all the affine functions are

  13. Symmetric corticobasal degeneration (S-CBD)

    PubMed Central

    Hassan, Anhar; Boeve, Bradley F.; Whitwell, Jennifer L.; Jack, Clifford R; Parisi, Joseph E.; Dickson, Dennis W.; Josephs, Keith A.

    2010-01-01

    Background Corticobasal degeneration (CBD) is a neurodegenerative disease characterized pathologically by neuronal loss, gliosis and tau deposition in neocortex, basal ganglia and brainstem. Typical clinical presentation is known as corticobasal syndrome (CBS) and involves the core features of progressive asymmetric rigidity and apraxia, accompanied by other signs of cortical and extrapyramidal dysfunction. Asymmetry is also emphasized on neuroimaging. Objective To describe a series of cases of CBD with symmetric clinical features and to compare clinical and imaging features of these symmetric CBD cases (S-CBD) to typical cases of CBS with CBD pathology. Methods All cases of pathologically confirmed CBD from the Mayo Clinic Rochester database were identified. Clinical records were reviewed and quantitative volumetric analysis of symmetric atrophy on head MRI using atlas based parcellation was performed. Subjects were classified as S-CBD if no differences had been observed between right- and left-sided cortical or extrapyramidal signs or symptoms. S-CBD cases were compared to 10 randomly selected typical CBS cases. Results Five cases (2 female) met criteria for S-CBD. None had limb dystonia, myoclonus, apraxia or alien limb phenomena. S-CBD cases had significantly less asymmetric atrophy when compared with CBS cases (p=0.009); they were also younger at onset (median 61 versus 66 years, p<0.05) and death (67 versus 73 years, p<0.05). Family history was present in 40% of S-CBD cases. Conclusions CBD can have a symmetric presentation, clinically and radiologically, in which typical features of CBS, such as limb apraxia, myoclonus, dystonia and alien limb phenomenon, may be absent. PMID:20018548

  14. Symmetric vertex models on planar random graphs

    Microsoft Academic Search

    D. A. Johnston

    1999-01-01

    We solve a 4-(bond)-vertex model on an ensemble of 3-regular (?3) planar random graphs, which has the effect of coupling the vertex model to 2D quantum gravity. The method of solution, by mapping onto an Ising model in field, is inspired by the solution by Wu et.al. of the regular lattice equivalent – a symmetric 8-vertex model on the honeycomb

  15. Symmetric vertex models on planar random graphs

    Microsoft Academic Search

    D. A. Johnston

    1999-01-01

    We solve a 4-(bond)-vertex model on an ensemble of 3-regular (Phi3) planar random graphs, which has the effect of coupling the vertex model to 2D quantum gravity. The method of solution, by mapping onto an Ising model in field, is inspired by the solution by Wu et.al. of the regular lattice equivalent - a symmetric 8-vertex model on the honeycomb

  16. An assessment of the LCD method for solving linear systems arising in SDFEM

    E-print Network

    John, Volker

    An assessment of the LCD method for solving linear systems arising in SDFEM discretizations¨ucken, Germany Abstract A numerical assessment of the recently proposed left conjugate direction method (LCD) for solving non­symmetric systems of linear equations is presented. A restarted version of LCD is compared

  17. STABILITY OF SECOND-ORDER ASYMMETRIC LINEAR MECHANICAL SYSTEMS WITH APPLICATION TO ROBOT GRASPING

    E-print Network

    Shapiro, Amir

    is concerned with the stability of second-order linear systems that have an asymmetric stiffness matrix. Our that the symmetric part of the stiffness matrix, ´Kpµs 1 2 ´Kp · KT p µ, is positive definite. This assumption hasSTABILITY OF SECOND-ORDER ASYMMETRIC LINEAR MECHANICAL SYSTEMS WITH APPLICATION TO ROBOT GRASPING

  18. The Nonlinear Evolution of Idealized, Unforced, Conditional Symmetric Instability: A Numerical Study.

    NASA Astrophysics Data System (ADS)

    Persson, P. Ola G.; Warner, Thomas T.

    1995-10-01

    A two-dimensional version of the Penn State-NCAR mesoscale model (MM4) has been used to simulate the life cycle of conditional symmetric instability (CSI) under conditions of no deformational or planetary boundary layer forcing with the model starting from idealized initial conditions. Detailed diagnostics from the growth, decay, and post-CSI stages of the life cycle are presented, and some of these features are compared to expectations from linear theory.The life cycle features include local areas of potential and inertial instability and specific patterns of ageo-strophic zonal flow. Local areas of increased and decreased dry potential vorticity (q), including areas of negative q, develop from the initially everywhere-positive q field, principally because of the horizontally differential diabatic heating. Negative wet-bulb potential vorticity (qw) is principally advected into the upper troposphere by the CSI updraft, though some changes in qw do occur because of the diffusion of temperature. Model-output soundings along surfaces of constant absolute momentum (m) show that lower-tropospheric thermodynamic stabilization and a decrease in slantwise convective available potential energy occur during the simulation. Net changes produced by the CSI circulations include low-level frontogenesis, upper-level frontolysis, and local buoyant and inertial stabilization-destabilization.The modeled updraft slope is between that of the surfaces of constant wet-bulb potential temperature (w) and that of the surfaces of constant m, since the viscosity and finite grid spacing yield an unstable mode with a finite updraft width. Such a mode differs from the inviscid mode, which has an infinitely narrow updraft width and a slope along the w surfaces. The cessation of the CSI is not due to the removal of the area of negative moist potential vorticity. Instead, linear stability analysis suggests that the cessation is due to the stabilization of modes with resolvable updraft widths and, possibly, to the depletion of the water vapor supply.Idealized studies such as these do not attempt to achieve absolute realism but are necessary steps in the methodical process of linking simple theoretical treatment of CSI with the complex observations; they may be useful as aids in interpreting observational data or numerical model simulations of real-atmosphere cases.

  19. Center-symmetric 1/N expansion

    SciTech Connect

    Schaden, Martin [Department of Physics, Rutgers University in Newark, 365 Smith Hall, 101 Warren Street, Newark, New Jersey 07102 (United States)

    2005-05-15

    The free energy of U(N) gauge theory is expanded about a center-symmetric topological background configuration with vanishing action and vanishing Polyakov loops. We construct this background for SU(N) lattice gauge theory and show that it uniquely describes center-symmetric minimal action orbits in the limit of infinite lattice volume. The leading contribution to the free energy in the 1/N expansion about this background is of O(N{sup 0}) rather than O(N{sup 2}) as one finds when the center symmetry is spontaneously broken. The contribution of planar 't Hooft diagrams to the free energy is O(1/N{sup 2}) and subleading in this case. The change in behavior of the diagrammatic expansion is traced to Linde's observation that the usual perturbation series of non-Abelian gauge theories suffers from severe infrared divergences [A. Linde, Phys. Lett. B 96, 289 (1980).]. This infrared problem does not arise in a center-symmetric expansion. The 't Hooft coupling {lambda}=g{sup 2}N is found to decrease {proportional_to}1/ln(N) for large N. There is evidence of a vector-ghost in the planar truncation of the model.

  20. Universal horizons in maximally symmetric spaces

    E-print Network

    Jishnu Bhattacharyya; David Mattingly

    2014-08-27

    Universal horizons in Ho\\v{r}ava-Lifshitz gravity and Einstein-{\\ae}ther theory are the equivalent of causal horizons in general relativity and appear to have many of the same properties, including a first law of horizon thermodynamics and thermal radiation. Since universal horizons are infrared solutions of a putative power counting renormalizable quantum gravitational theory, fully understanding their thermodynamics will shed light on the interplay between black hole thermodynamics and quantum gravity. In this paper, we provide a complete classification, including asymptotic charges, of all four dimensional static and spherically symmetric universal horizon solutions with maximally symmetric asymptotics -- the equivalents of the Schwarzschild, Schwarzschild de Sitter or Schwarzschild anti-de Sitter spacetimes. Additionally we derive the associated first laws for the universal horizon solutions. Finally we prove that independent of asymptotic boundary conditions, any spherically symmetric solution in Ho\\v{r}ava-Lifshitz gravity with a universal horizon is also a solution of Einstein-{\\ae}ther theory, thereby broadening and complementing the known equivalence region of the solution spaces.

  1. Super-symmetric informationally complete measurements

    E-print Network

    Huangjun Zhu

    2014-12-02

    Symmetric informationally complete measurements (SICs in short) are highly symmetric structure in the Hilbert space. They possess many nice properties which render them an ideal candidate of fiducial measurements. The symmetry of SICs is intimately connected with the geometry of the quantum state space and also has profound implications for foundational studies. Here we study those SICs that are most symmetric according to a natural criterion and show that all of them are covariant with respect to the Heisenberg-Weyl groups, which are characterized by the discrete analog of the canonical commutation relation. Moreover, their symmetry groups are subgroups of the Clifford groups. In particular, we prove that the SIC in dimension~2, the Hesse SIC in dimension~3, and the set of Hoggar lines in dimension~8 are the only three SICs up to unitary equivalence whose symmetry groups act transitively on pairs of SIC projectors. Our work is of intrinsic interest to studying the geometry of quantum state space and foundational issues entangled with the geometry.

  2. ?to e in R-symmetric Supersymmetry

    E-print Network

    Ricky Fok; Graham D. Kribs

    2010-11-23

    We demonstrate that mu/e slepton mixing is significantly more restricted than previously thought within the already remarkably flavor-safe R-symmetric supersymmetric standard model. We calculate bounds from mu to e gamma, mu to 3e and, most importantly, mu to e conversion. The process mu to e conversion is significantly more restrictive in R-symmetric models since this process can occur through operators that do not require a chirality-flip. We delineate the allowed parameter space, demonstrating that maximal mixing is rarely possible with weak scale superpartners, while O(0.1) mixing is permitted within most of the space. The best approach to find or rule out mu/e mixing in R-symmetric supersymmetric models is a multi-pronged attack looking at both mu to e conversion as well as mu to e gamma. The redundancy eliminates much of the parameter space where one process, but not both processes, contain amplitudes that accidentally destructively interfere. We briefly discuss implications for searches of slepton flavor violation at the LHC.

  3. Spherically Symmetric Thick Branes Cosmological Evolution

    E-print Network

    Alex E. Bernardini; R. T. Cavalcanti; Roldao da Rocha

    2014-11-13

    Spherically symmetric time-dependent solutions for the 5D system of a scalar field canonically coupled to gravity are obtained and identified as an extension of recent results obtained by Ahmed, Grzadkowskia and Wudkab. The corresponding cosmology of models with regularized branes generated by such a 5D scalar field scenario is also investigated. It has been shown that the anisotropic evolution of the warp factor and consequently the Hubble like parameter are both driven by the radial coordinate on the brane, which leads to an emergent thick brane-world scenario with spherically symmetric time dependent warp factor. Meanwhile, the separability of variables depending on fifth dimension, y, which is exhibited by the equations of motion, allows one to recover the extra dimensional profiles obtained in the literature, namely the extra dimensional part of the scale (warp) factor and the scalar field dependence on y. Therefore, our results are mainly concerned with the time dependence of a spherically symmetric warp factor. Besides evincing possibilities for obtaining asymmetric stable brane-world scenarios, the extra dimensional profiles here obtained can also be reduced to those ones investigated in the literature.

  4. The EPSILON experimental pseudo-symmetric trap

    NASA Astrophysics Data System (ADS)

    Arsenin, V. V.; Dlougach, E. D.; Kulygin, V. M.; Kuyanov, A. Yu.; Skovoroda, A. A.; Timofeev, A. V.; Zhil'tsov, V. A.; Zvonkov, A. V.

    2001-07-01

    Within the framework of the Adaptive Plasma Experiment (APEX) conceptual project, a trap with closed magnetic field lines, the Experimental Pseudo-Symmetric Closed Trap (EPSILON), is examined. The APEX project is aimed at theoretical and experimental development of the physical foundations for a steady state thermonuclear reactor designed on the basis of an alternative magnetic trap with tokamak-like large ? plasma confinement. A discussion is given of the fundamental principle of pseudo-symmetry, which a magnetic configuration with tokamak-like plasma confinement should satisfy. Examples are given of calculations in the paraxial approximation of pseudo-symmetric curvilinear elements with a poloidal modulus B isoline. The EPSILON trap, consisting of two direct axisymmetric mirrors linked by two curvilinear pseudo-symmetric elements, is considered. To increase the equilibrium ?, the plasma currents are short-circuited within curvilinear equilibrium elements. An untraditional scheme of MHD stabilization for a trap with closed field lines by use of axisymmetric mirrors with a divertor is analysed. The experimental installation EPSILON-One Mirror Element (OME), which is under construction for experimental investigation of stabilization by divertor, is discussed. The opportunity for applying the ECR method of plasma production in EPSILON-OME in conditions of high density and low magnetic field is examined.

  5. Replication of Avocado Sunblotc Viroid: Evidence for a Symmetric Pathway with Two Rolling Circles and Hammerhead Ribozyme Processing

    Microsoft Academic Search

    Jose A. Daros; Jose F. Marcos; Carmen Hernandez; Ricardo Flores

    1994-01-01

    The structure of a series of RNAs extracted from avocado infected by the 247-nt avocado sunblotch viroid (ASBVd) was investigated. The identification of multistranded complexes containing circular ASBVd RNAs of (+) and (-) polarity suggests that replication of ASBVd proceeds through a symmetric pathway with two rolling circles where these two circular RNAs are the templates. This is in contrast

  6. Gap solitons in PT-symmetric optical lattices with higher-order diffraction.

    PubMed

    Ge, Lijuan; Shen, Ming; Ma, Chunlan; Zang, Taocheng; Dai, Lu

    2014-12-01

    The existence and stability of gap solitons are investigated in the semi-infinite gap of a parity-time (PT)-symmetric periodic potential (optical lattice) with a higher-order diffraction. The Bloch bands and band gaps of this PT-symmetric optical lattice depend crucially on the coupling constant of the fourth-order diffraction, whereas the phase transition point of this PT optical lattice remains unchangeable. The fourth-order diffraction plays a significant role in destabilizing the propagation of dipole solitons. Specifically, when the fourth-order diffraction coupling constant increases, the stable region of the dipole solitons shrinks as new regions of instability appear. However, fundamental solitons are found to be always linearly stable with arbitrary positive value of the coupling constant. We also investigate nonlinear evolution of the PT solitons under perturbation. PMID:25606878

  7. Symmetric RBF classifier for nonlinear detection in multiple-antenna-aided systems.

    PubMed

    Chen, Sheng; Wolfgang, Andreas; Harris, Chris J; Hanzo, Lajos

    2008-05-01

    In this paper, we propose a powerful symmetric radial basis function (RBF) classifier for nonlinear detection in the so-called "overloaded" multiple-antenna-aided communication systems. By exploiting the inherent symmetry property of the optimal Bayesian detector, the proposed symmetric RBF classifier is capable of approaching the optimal classification performance using noisy training data. The classifier construction process is robust to the choice of the RBF width and is computationally efficient. The proposed solution is capable of providing a signal-to-noise ratio (SNR) gain in excess of 8 dB against the powerful linear minimum bit error rate (BER) benchmark, when supporting four users with the aid of two receive antennas or seven users with four receive antenna elements. PMID:18467204

  8. Adaptive nonlinear least bit error-rate detection for symmetrical RBF beamforming.

    PubMed

    Chen, S; Wolfgang, A; Harris, C J; Hanzo, L

    2008-01-01

    A powerful symmetrical radial basis function (RBF) aided detector is proposed for nonlinear detection in so-called rank-deficient multiple-antenna assisted beamforming systems. By exploiting the inherent symmetry of the optimal Bayesian detection solution, the proposed RBF detector becomes capable of approaching the optimal Bayesian detection performance using channel-impaired training data. A novel nonlinear least bit error algorithm is derived for adaptive training of the symmetrical RBF detector based on a stochastic approximation to the Parzen window estimation of the detector output's probability density function. The proposed adaptive solution is capable of providing a signal-to-noise ratio gain in excess of 8 dB against the theoretical linear minimum bit error rate benchmark, when supporting four users with the aid of two receive antennas or seven users employing four receive antenna elements. PMID:18207699

  9. Cutting Force Predication Based on Integration of Symmetric Fuzzy Number and Finite Element Method

    PubMed Central

    Wang, Zhanli; Hu, Yanjuan; Wang, Yao; Dong, Chao; Pang, Zaixiang

    2014-01-01

    In the process of turning, pointing at the uncertain phenomenon of cutting which is caused by the disturbance of random factors, for determining the uncertain scope of cutting force, the integrated symmetric fuzzy number and the finite element method (FEM) are used in the prediction of cutting force. The method used symmetric fuzzy number to establish fuzzy function between cutting force and three factors and obtained the uncertain interval of cutting force by linear programming. At the same time, the change curve of cutting force with time was directly simulated by using thermal-mechanical coupling FEM; also the nonuniform stress field and temperature distribution of workpiece, tool, and chip under the action of thermal-mechanical coupling were simulated. The experimental result shows that the method is effective for the uncertain prediction of cutting force. PMID:24790556

  10. Relative equilibria in the unrestricted problem of a sphere and symmetric rigid body

    NASA Astrophysics Data System (ADS)

    Vereshchagin, Mikhail; Maciejewski, Andrzej J.; Go?dziewski, Krzysztof

    2010-04-01

    We consider the unrestricted problem of two mutually attracting rigid bodies, a uniform sphere (or a point mass) and an axially symmetric body. We present a global, geometric approach for finding all relative equilibria (stationary solutions) in this model, which was already studied by Kinoshita. We extend and generalize his results, showing that the equilibria solutions may be found by solving at most two non-linear, algebraic equations, assuming that the potential function of the symmetric rigid body is known explicitly. We demonstrate that there are three classes of the relative equilibria, which we call cylindrical, inclined coplanar and conic precessions, respectively. Moreover, we also show that in the case of conic precession, although the relative orbit is circular, the point mass and the mass centre of the body move in different parallel planes. This solution has not been known yet in the literature.

  11. A microscopic derivation of nuclear collective rotation-vibration model, axially symmetric case

    E-print Network

    Parviz Gulshani

    2015-05-12

    We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed the to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms and applied to the ground-state rotational bands in some axially-symmetric nuclei. The results are compared with the measured data.

  12. Concentration of diffuse linear light sources with continuous optical elements.

    PubMed

    Davidson, N; Khaykovich, L

    1999-06-01

    A new technique for geometric transformation of a diffuse linear light source into a two-dimensional symmetric virtual source is proposed and demonstrated. It involves two cylindrical lenses and a single holographic element that is optically recorded with a simple and single step. The results for a specific arrangement that transforms a 40 mm x 0.4 mm source, with diffusive angle of 0.1 rad, into a 1 mm x 1.2 mm nearly symmetric spot are presented. The lack of sharp boundaries in either the beam or the optical elements suppresses any diffraction losses, relaxes alignment tolerances, and improves stability. PMID:18319961

  13. Linear Syzygies Of Stanley-Reisner Ideals

    Microsoft Academic Search

    V. Reiner; V. Welker

    1998-01-01

    . We give an elementary description of the maps in the linear strandof the minimal free resolution of a square-free monomial ideal, that is, theStanley-Reisner ideal associated to a simplicial complex \\\\Delta. The descriptionis in terms of the homology of the canonical Alexander dual complex \\\\Delta. Asapplications we are able toffl prove for monomial ideals and j = 1 a

  14. Adsorption of symmetric random copolymer onto symmetric random surface: the annealed case

    E-print Network

    A. A. Polotsky

    2015-06-12

    Adsorption of a symmetric (AB) random copolymer (RC) onto a symmetric (ab) random heterogeneous surface (RS) is studied in the annealed approximation by using a two-dimensional partially directed walk model of the polymer. We show that in the symmetric case, the expected a posteriori compositions of the RC and the RS have correct values (corresponding to their a priori probabilities) and do not change with the temperature, whereas second moments of monomers and sites distributions in the RC and RS change. This indicates that monomers and sites do not interconvert but only rearrange in order to provide better matching between them and, as a result, a stronger adsorption of the RC on the RS. However, any violation of the system symmetry shifts equilibrium towards the major component and/or more favorable contacts and leads to interconversion of monomers and sites.

  15. Three-Dimensional Structures of the Spatiotemporal Nonlinear Schrödinger Equation with Power-Law Nonlinearity in PT-Symmetric Potentials

    PubMed Central

    Dai, Chao-Qing; Wang, Yan

    2014-01-01

    The spatiotemporal nonlinear Schrödinger equation with power-law nonlinearity in -symmetric potentials is investigated, and two families of analytical three-dimensional spatiotemporal structure solutions are obtained. The stability of these solutions is tested by the linear stability analysis and the direct numerical simulation. Results indicate that solutions are stable below some thresholds for the imaginary part of -symmetric potentials in the self-focusing medium, while they are always unstable for all parameters in the self-defocusing medium. Moreover, some dynamical properties of these solutions are discussed, such as the phase switch, power and transverse power-flow density. The span of phase switch gradually enlarges with the decrease of the competing parameter k in -symmetric potentials. The power and power-flow density are all positive, which implies that the power flow and exchange from the gain toward the loss domains in the cell. PMID:24983624

  16. Three-dimensional structures of the spatiotemporal nonlinear Schrödinger equation with power-law nonlinearity in PT-symmetric potentials.

    PubMed

    Dai, Chao-Qing; Wang, Yan

    2014-01-01

    The spatiotemporal nonlinear Schrödinger equation with power-law nonlinearity in PT-symmetric potentials is investigated, and two families of analytical three-dimensional spatiotemporal structure solutions are obtained. The stability of these solutions is tested by the linear stability analysis and the direct numerical simulation. Results indicate that solutions are stable below some thresholds for the imaginary part of PT-symmetric potentials in the self-focusing medium, while they are always unstable for all parameters in the self-defocusing medium. Moreover, some dynamical properties of these solutions are discussed, such as the phase switch, power and transverse power-flow density. The span of phase switch gradually enlarges with the decrease of the competing parameter k in PT-symmetric potentials. The power and power-flow density are all positive, which implies that the power flow and exchange from the gain toward the loss domains in the PT cell. PMID:24983624

  17. Three-Dimensional Solutions for Contact Area in Laminated Composite Pinned Joints with Symmetric and Non-Symmetric Stacking Sequences

    NASA Astrophysics Data System (ADS)

    Javadi, H.; Rajabi, I.; Yavari, V.; Kadivar, M. H.

    The aim of this study is computing and evaluating the behavior of the laminated composite plate at the contact area in single lap, mechanically fastened joints. The analyses involve three dimensional finite element models performed by ABAQUS 6.4-PR11 code to evaluate the stress distribution in contact surface, separation angle, the magnitude and location of maximum radial stress. Results are determined for composite laminates with different layer configurations and attempts are made to validate the models with previous works. For cross ply and angle ply configurations only symmetric stacking sequences are used while for quasi-isotropic laminate both symmetric and non-symmetric models are generated. In cross-ply laminate symmetric separation about bearing plane could be found while in quasi-isotropic and angle-ply laminates non-symmetric separation occurs. Also, the separation angle is less than 90° in symmetric laminates and greater than 90° in some plies of non-symmetric laminates.

  18. LINEAR DIFFUSION Erkut Erdem

    E-print Network

    Erdem, Erkut

    LINEAR DIFFUSION Erkut Erdem Hacettepe University February 24th, 2012 CONTENTS 1 Linear Diffusion 1 2 Appendix - The Calculus of Variations 5 References 6 1 LINEAR DIFFUSION The linear diffusion (heat (noisy) input image and u(x, t) be initialized with u(x, 0) = u0(x) = f (x). Then, the linear diffusion

  19. Symmetrical and anti-symmetrical coherent perfect absorption for acoustic waves

    SciTech Connect

    Wei, Pengjiang; Croënne, Charles; Tak Chu, Sai [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Li, Jensen, E-mail: j.li@bham.ac.uk [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2014-03-24

    We investigate tunable acoustic absorption enabled by the coherent control of input waves. It relies on coherent perfect absorption originally proposed in optics. By designing appropriate acoustic metamaterial structures with resonating effective bulk modulus or density, we show that complete absorption of incident waves impinging on the metamaterial can be achieved for either symmetrical or anti-symmetrical inputs in the forward and backward directions. By adjusting the relative phase between the two incident beams, absorption can be tuned effectively from unity to zero, making coherent control useful in applications like acoustic modulators, noise controllers, transducers, and switches.

  20. Linear ubiquitination signals in adaptive immune responses.

    PubMed

    Ikeda, Fumiyo

    2015-07-01

    Ubiquitin can form eight different linkage types of chains using the intrinsic Met 1 residue or one of the seven intrinsic Lys residues. Each linkage type of ubiquitin chain has a distinct three-dimensional topology, functioning as a tag to attract specific signaling molecules, which are so-called ubiquitin readers, and regulates various biological functions. Ubiquitin chains linked via Met 1 in a head-to-tail manner are called linear ubiquitin chains. Linear ubiquitination plays an important role in the regulation of cellular signaling, including the best-characterized tumor necrosis factor (TNF)-induced canonical nuclear factor-?B (NF-?B) pathway. Linear ubiquitin chains are specifically generated by an E3 ligase complex called the linear ubiquitin chain assembly complex (LUBAC) and hydrolyzed by a deubiquitinase (DUB) called ovarian tumor (OTU) DUB with linear linkage specificity (OTULIN). LUBAC linearly ubiquitinates critical molecules in the TNF pathway, such as NEMO and RIPK1. The linear ubiquitin chains are then recognized by the ubiquitin readers, including NEMO, which control the TNF pathway. Accumulating evidence indicates an importance of the LUBAC complex in the regulation of apoptosis, development, and inflammation in mice. In this article, I focus on the role of linear ubiquitin chains in adaptive immune responses with an emphasis on the TNF-induced signaling pathways. PMID:26085218

  1. Symmetric Euler orientation representations for orientational averaging.

    PubMed

    Mayerhöfer, Thomas G

    2005-09-01

    A new kind of orientation representation called symmetric Euler orientation representation (SEOR) is presented. It is based on a combination of the conventional Euler orientation representations (Euler angles) and Hamilton's quaternions. The properties of the SEORs concerning orientational averaging are explored and compared to those of averaging schemes that are based on conventional Euler orientation representations. To that aim, the reflectance of a hypothetical polycrystalline material with orthorhombic crystal symmetry was calculated. The calculation was carried out according to the average refractive index theory (ARIT [T.G. Mayerhöfer, Appl. Spectrosc. 56 (2002) 1194]). It is shown that the use of averaging schemes based on conventional Euler orientation representations leads to a dependence of the result from the specific Euler orientation representation that was utilized and from the initial position of the crystal. The latter problem can be overcome partly by the introduction of a weighing factor, but only for two-axes-type Euler orientation representations. In case of a numerical evaluation of the average, a residual difference remains also if a two-axes type Euler orientation representation is used despite of the utilization of a weighing factor. In contrast, this problem does not occur if a symmetric Euler orientation representation is used as a matter of principle, while the result of the averaging for both types of orientation representations converges with increasing number of orientations considered in the numerical evaluation. Additionally, the use of a weighing factor and/or non-equally spaced steps in the numerical evaluation of the average is not necessary. The symmetrical Euler orientation representations are therefore ideally suited for the use in orientational averaging procedures. PMID:16043055

  2. Symmetrical band-pass loudspeaker systems

    NASA Astrophysics Data System (ADS)

    Matusiak, Grzegorz Piotr

    2001-12-01

    Loudspeaker systems are analyzed in a doctoral dissertation. The dissertation concerns loudspeaker systems, which are known as subwoofers or band-pass loudspeaker systems. Their advantages include: high- quality sound reproduction in the low-frequency range, small dimensions, small nonlinear distortions and the fact that they can be placed anywhere in a room or car. Band-pass loudspeaker systems are used widely in the so- called Home Theatre as well as to provide sound in cinema, theatre, concert, discotheque, opera, operetta, philharmonic and amphitheater halls, at open-air concerts, and so on. Various designs are mass-produced by a large number of manufacturers. The study covers an analysis of band-pass loudspeaker systems to which the frequency transformation, i.e. the reactance transformation, has been applied. Since this is a symmetrical transformation, amplitude frequency responses of the studied band-pass systems are also symmetrical (logarithmic scale of a frequency). As a result, the high-pass loudspeaker system design method, known as the Thiele-Small, Benson analysis, can be employed. The investigations include the formulation of band-pass system equations (fourth, sixth and eighth-order polynomials) and the subsequent derivation of relations for the calculation of system parameters. The obtained results enable the calculation of optimum designs for prescribed alignments, e.g. (Chebyshev) equal-ripple, (Butterworth) maximally flat, or quasi-maximally flat (QB). The analysis covers fourth, sixth and eighth-order symmetrical systems. Eighth-order systems have been divided into three kinds according to three ways of physical realization. The doctoral dissertation includes band-pass loudspeaker systems, which can be designed with active or passive filters or without the filter. Designed systems consist of a loudspeaker whose front of a diaphragm is loaded with a Helmholtz resonator, i.e. an enclosure with a vent, which radiates sound outwards. The back is loaded with a closed-box or the Helmholtz resonator.

  3. Microfabricated linear Paul-Straubel ion trap

    DOEpatents

    Mangan, Michael A. (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Tigges, Chris P. (Albuquerque, NM); Linker, Kevin L. (Albuquerque, NM)

    2011-04-19

    An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

  4. Expanding symmetric multiprocessor capability through gang scheduling

    SciTech Connect

    Jette, M.A.

    1998-03-01

    Symmetric Multiprocessor (SMP) systems normally provide both space- sharing and time-sharing to insure high system utilization and good responsiveness. However the prevailing lack of concurrent scheduling for parallel programs precludes SMP use in addressing many large-scale problems. Tightly synchronized communications are impractical and normal time-sharing reduces the benefit of cache memory. Evidence gathered at Lawrence Livermore National Laboratory (LLNL) indicates that gang scheduling can increase the capability of SMP systems and parallel program performance without adverse impact upon system utilization or responsiveness.

  5. Gapped symmetric boundaries of topological insulators

    NASA Astrophysics Data System (ADS)

    Lee, Dung-Hai; Lu, Yuan-Ming

    2014-03-01

    Topological insulators (TIs) are gapped quantum phases which host symmetry-protected gapless boundary excitations. On the other hand, the boundary states can be gapped by spontaneously breaking symmetry. We show that topological defects on the symmetry-broken boundary cannot proliferate due to their fractional statistics. A gapped symmetric boundary, however, can be achieved between a TI phase and certain fractionalized phase by condensing the bound state of a topological defect and an anyon. Such a hybrid structure containing TI and fractionalized phase generally support ground state degeneracy on torus.

  6. Single mode PT symmetric large area lasers

    NASA Astrophysics Data System (ADS)

    Hodaei, Hossein; Miri, Mohammad-Ali; Heinrich, Matthias; Christodoulides, Demetrios N.; Khajavikhan, Mercedeh

    2014-09-01

    We experimentally demonstrate single longitudinal mode operation in microring laser using the concept of PT symmetry. A PT-symmetric coupled resonator arrangement can considerably enhance the maximum achievable gain of single mode microring cavity. The method is broadband thus work well for inhomogenously broadened gain mediums. It doesn't rely on any additional component to ensure its mode selective performance, and it is robust with respect to fabrication inaccuracies. This result may pave the way for a novel way of designing integrated laser sources based on PT symmetry.

  7. Quantum asymmetric cryptography with symmetric keys

    E-print Network

    Fei Gao; Qiao-Yan Wen; Su-Juan Qin; Fu-Chen Zhu

    2008-10-16

    Based on quantum encryption, we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme, which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore, the state-estimation attack to a prior QPKC scheme is demonstrated.

  8. Communities and classes in symmetric fractals

    NASA Astrophysics Data System (ADS)

    Krawczyk, Ma?gorzata J.

    2015-07-01

    Two aspects of fractal networks are considered: the community structure and the class structure, where classes of nodes appear as a consequence of a local symmetry of nodes. The analyzed systems are the networks constructed for two selected symmetric fractals: the Sierpinski triangle and the Koch curve. Communities are searched for by means of a set of differential equations. Overlapping nodes which belong to two different communities are identified by adding some noise to the initial connectivity matrix. Then, a node can be characterized by a spectrum of probabilities of belonging to different communities. Our main goal is that the overlapping nodes with the same spectra belong to the same class.

  9. LINEAR DATA DECOMPOSITION METHODS FOR FORCED NON-LINEAR SPATIOTEMPORAL SYSTEMS

    E-print Network

    Texas at San Antonio, University of

    convection loop. The spatial complexity and dynamic properties of this system can be controlled by adjusting the convection loop model and is also ineffective at separating the system's solutions from linear mixtures. PCA

  10. Photovoltaic effect in symmetrical cells of a liquid crystal porphyrin

    SciTech Connect

    Gregg, B.A.; Fox, M.A.; Bard, A.J. (Univ. of Texas, Austin (USA))

    1990-02-22

    An unusual photovoltaic effect has been observed in symmetrical cells consisting of indium-tin oxide (ITO) electrodes and a liquid crystal porphyrin (LCP, zinc octakis({beta}-octyloxyethyl)porphyrin). The illuminated electrode acts as a photoanode; the direction of current flow reverses upon reversal of the direction of illumination. Stable photocurrents of up to ca. 0.4 mA/cm{sup 2} have been measured under illumination with a 150-W Xe lamp (intensity ca. 150 mW/cm{sup 2}). The photocurrent increases linearly with incident light intensity (I{sub 0}) at all wavelengths up to I{sub 0} > 10{sup 15} photons s{sup {minus}1} cm{sup {minus}2}. This photovoltaic effect is interpreted as resulting from exciton dissociation at the illuminated electrode leading to the preferential photoinjection of electrons into the ITO electrode and holes into the porphyrin. This appears to be the first unambiguous example of a photovoltaic cell controlled entirely by interfacial kinetics.

  11. Effects of the Chain Architecture on the Miscibility of Symmetric Linear/Linear and Star/Star Polymer Blends

    E-print Network

    Theodorakis, Panagiotis E.

    Versity of Ioannina, 45110 Ioannina, Greece J. J. Freire Departamento de Ciencias y Te´cnicas Fisicoqui´micas, Uni and C. Vlahos* Department of Chemistry, UniVersity of Ioannina, 45110 Ioannina, Greece ReceiVed March 14

  12. Electroweak Baryogenesis in R-symmetric Supersymmetry

    SciTech Connect

    Fok, R.; Kribs, Graham D.; Martin, Adam; Tsai, Yuhsin

    2013-03-01

    We demonstrate that electroweak baryogenesis can occur in a supersymmetric model with an exact R-symmetry. The minimal R-symmetric supersymmetric model contains chiral superfields in the adjoint representation, giving Dirac gaugino masses, and an additional set of "R-partner" Higgs superfields, giving R-symmetric \\mu-terms. New superpotential couplings between the adjoints and the Higgs fields can simultaneously increase the strength of the electroweak phase transition and provide additional tree-level contributions to the lightest Higgs mass. Notably, no light stop is present in this framework, and in fact, we require both stops to be above a few TeV to provide sufficient radiative corrections to the lightest Higgs mass to bring it up to 125 GeV. Large CP-violating phases in the gaugino/higgsino sector allow us to match the baryon asymmetry of the Universe with no constraints from electric dipole moments due to R-symmetry. We briefly discuss some of the more interesting phenomenology, particularly of the of the lightest CP-odd scalar.

  13. Fast numerical determination of symmetric sparsity patterns

    SciTech Connect

    Carter, R.G. [Univ. of Minnesota, Minneapolis (United States)

    1994-08-01

    The author considers a function g: {Re}{sup n} {yields} {Re}{sup n} for which the Jacobian is symmetric and sparse. Such functions often arise, for instance, in numerical optimization, where g is the gradient of some objective function f so that the Jacobian of g is the Hessian of f. In many such applications one can generate extremely efficient algorithms by taking advantage of the sparsity structure of the problem if this pattern is known a priori. Unfortunately, determining such sparsity structures by hand is often difficult and prone to error. If one suspects a mistake has been made, or if g is a {open_quotes}black box{close_quotes} so that the true structure is completely unknown, one often has no alternative but to compute the entire matrix by finite differences - a prohibitively expensive task for large problems. The author shows that it is possible to numerically determine symmetric sparsity patterns using a relatively small number of g evaluations. Numerical results are shown for n up to 100,000 in which all nonzeros in the Jacobian are correctly identified in about one-hundredth of the time required to estimate the sparsity structure by a full finite difference calculation. When a good initial guess for the sparsity structure is available, numerical results are presented for n up to 500,000, in which all missing nonzeros are correctly located almost five-thousand times faster than would be possible with a full finite difference calculation.

  14. Compressible flow about symmetrical Joukowski profiles

    NASA Technical Reports Server (NTRS)

    Kaplan, Carl

    1938-01-01

    The method of Poggi is employed for the determination of the effects of compressibility upon the flow past an obstacle. A general expression for the velocity increment due to compressibility is obtained. The general result holds whatever the shape of the obstacle; but, in order to obtain the complete solution, it is necessary to know a certain Fourier expansion of the square of the velocity of flow past the obstacle. An application is made to the case flow of a symmetrical Joukowski profile with a sharp trailing edge, fixed in a stream of an arbitrary angle of attack and with the circulation determined by the Kutta condition. The results are obtained in a closed form and are exact insofar as the second approximation to the compressible flow is concerned, the first approximation being the result for the corresponding incompressible flow. Formulas for lift and moment analogous to the Blasius formulas in incompressible flow are developed and are applied to thin symmetrical Joukowski profiles for small angles of attack.

  15. The modelling of symmetric airfoil vortex generators

    NASA Technical Reports Server (NTRS)

    Reichert, B. A.; Wendt, B. J.

    1996-01-01

    An experimental study is conducted to determine the dependence of vortex generator geometry and impinging flow conditions on shed vortex circulation and crossplane peak vorticity for one type of vortex generator. The vortex generator is a symmetric airfoil having a NACA 0012 cross-sectional profile. The geometry and flow parameters varied include angle-of-attack alfa, chordlength c, span h, and Mach number M. The vortex generators are mounted either in isolation or in a symmetric counter-rotating array configuration on the inside surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio is delta/R = 0. 17. Circulation and peak vorticity data are derived from crossplane velocity measurements conducted at or about 1 chord downstream of the vortex generator trailing edge. Shed vortex circulation is observed to be proportional to M, alfa, and h/delta. With these parameters held constant, circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio AR. Shed vortex peak vorticity is also observed to be proportional to M, alfa, and h/delta. Unlike circulation, however, peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at AR approx. 2.0 before falling off.

  16. Adaptive linear generalized synchronization between two nonidentical networks

    Microsoft Academic Search

    Z. Q. Yang; Q. Zhang; Z. Q. Chen

    In this paper, the linear generalized synchronization between two nonidentical complex dynamical networks is investigated. Both non-delay and delay-coupled complex dynamical networks are studied. By designing effective adaptive controllers, the linear generalized synchronization between two networks with identical and nonidentical topological structures can realize. The feasibility of the proposed scheme is proved in theory and illustrative examples are presented to

  17. Linear Back-Drive Differentials

    NASA Technical Reports Server (NTRS)

    Waydo, Peter

    2003-01-01

    Linear back-drive differentials have been proposed as alternatives to conventional gear differentials for applications in which there is only limited rotational motion (e.g., oscillation). The finite nature of the rotation makes it possible to optimize a linear back-drive differential in ways that would not be possible for gear differentials or other differentials that are required to be capable of unlimited rotation. As a result, relative to gear differentials, linear back-drive differentials could be more compact and less massive, could contain fewer complex parts, and could be less sensitive to variations in the viscosities of lubricants. Linear back-drive differentials would operate according to established principles of power ball screws and linear-motion drives, but would utilize these principles in an innovative way. One major characteristic of such mechanisms that would be exploited in linear back-drive differentials is the possibility of designing them to drive or back-drive with similar efficiency and energy input: in other words, such a mechanism can be designed so that a rotating screw can drive a nut linearly or the linear motion of the nut can cause the screw to rotate. A linear back-drive differential (see figure) would include two collinear shafts connected to two parts that are intended to engage in limited opposing rotations. The linear back-drive differential would also include a nut that would be free to translate along its axis but not to rotate. The inner surface of the nut would be right-hand threaded at one end and left-hand threaded at the opposite end to engage corresponding right- and left-handed threads on the shafts. A rotation and torque introduced into the system via one shaft would drive the nut in linear motion. The nut, in turn, would back-drive the other shaft, creating a reaction torque. Balls would reduce friction, making it possible for the shaft/nut coupling on each side to operate with 90 percent efficiency.

  18. Performance enhancement of nonlinear drives by feedback linearization of linear-bilinear cascade models

    Microsoft Academic Search

    L. Del Re; A. Isidori

    1995-01-01

    Complex plants seldom fulfil the conditions required for the design of exact feedback linearizing controls. Using suitable approximate models, however, may allow the design of a feedback linearizing controller which, when applied to the true plant, leads to substantial performance enhancements provided the approximate model captures the essential characteristics of the plant. This paper discusses this issue in the case

  19. A geometrical relation between symmetric operators and mutually unbiased operators

    E-print Network

    Amir Kalev

    2013-05-26

    In this work we study the relation between the set of symmetric operators and the set of mutually unbiased operators from finite plane geometry point of view. Here symmetric operators are generalization of symmetric informationally complete probability-operator measurements (SIC POMs), while mutually unbiased operators are the operator generalization of mutually unbiased bases (MUB). We also discuss the implication of this relation to the particular cases of rank-1 SIC POMs and MUB.

  20. The inequality between mass and angular momentum for axially symmetric black holes

    E-print Network

    Sergio Dain

    2007-07-20

    In this essay I first discuss the physical relevance of the inequality $m\\geq \\sqrt{|J|}$ for axially symmetric (non-stationary) black holes, where m is the mass and J the angular momentum of the spacetime. Then, I present a proof of this inequality for the case of one spinning black hole. The proof involves a remarkable characterization of the extreme Kerr black hole as an absolute minimum of the total mass. Finally, I conjecture on the physical implications of this characterization for the non linear stability problem for black holes.