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Sample records for hermitian positive definite

  1. Positive Eigenvalues of Generalized Words in Two Hermitian Positive Definite Matrices

    OpenAIRE

    Hillar, Christopher; Johnson, Charles R.

    2005-01-01

    We define a word in two positive definite (complex Hermitian) matrices $A$ and $B$ as a finite product of real powers of $A$ and $B$. The question of which words have only positive eigenvalues is addressed. This question was raised some time ago in connection with a long-standing problem in theoretical physics, and it was previously approached by the authors for words in two real positive definite matrices with positive integral exponents. A large class of words that do guarantee positive eig...

  2. Equivalent Hermitian Hamiltonian for the non-Hermitian -x4 potential

    International Nuclear Information System (INIS)

    Jones, H.F.; Mateo, J.

    2006-01-01

    The potential V(x)=-x 4 , which is unbounded below on the real line, can give rise to a well-posed bound state problem when x is taken on a contour in the lower-half complex plane. It is then PT-symmetric rather than Hermitian. Nonetheless it has been shown numerically to have a real spectrum, and a proof of reality, involving the correspondence between ordinary differential equations and integrable systems, was subsequently constructed for the general class of potentials -(ix) N . For such Hamiltonians the natural PT metric is not positive definite, but a dynamically-defined positive-definite metric can be defined, depending on an operator Q. Further, with the help of this operator an equivalent Hermitian Hamiltonian h can be constructed. This programme has been carried out exactly for a few soluble models, and the first few terms of a perturbative expansion have been found for the potential m 2 x 2 +igx 3 . However, until now, the -x 4 potential has proved intractable. In the present paper we give explicit, closed form expressions for Q and h, which are made possible by a particular parametrization of the contour in the complex plane on which the problem is defined. This constitutes an explicit proof of the reality of the spectrum. The resulting equivalent Hamiltonian has a potential with a positive quartic term together with a linear term

  3. Pseudo-Hermitian coherent states under the generalized quantum condition with position-dependent mass

    International Nuclear Information System (INIS)

    Yahiaoui, S A; Bentaiba, M

    2012-01-01

    In the context of the factorization method, we investigate the pseudo-Hermitian coherent states and their Hermitian counterpart coherent states under the generalized quantum condition in the framework of a position-dependent mass. By considering a specific modification in the superpotential, suitable annihilation and creation operators are constructed in order to reproduce the Hermitian counterpart Hamiltonian in the factorized form. We show that by means of these ladder operators, we can construct a wide range of exactly solvable potentials as well as their accompanying coherent states. Alternatively, we explore the relationship between the pseudo-Hermitian Hamiltonian and its Hermitian counterparts, obtained from a similarity transformation, to construct the associated pseudo-Hermitian coherent states. These latter preserve the structure of Perelomov’s states and minimize the generalized position–momentum uncertainty principle. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

  4. A possible method for non-Hermitian and Non-PT-symmetric Hamiltonian systems.

    Directory of Open Access Journals (Sweden)

    Jun-Qing Li

    Full Text Available A possible method to investigate non-Hermitian Hamiltonians is suggested through finding a Hermitian operator η+ and defining the annihilation and creation operators to be η+ -pseudo-Hermitian adjoint to each other. The operator η+ represents the η+ -pseudo-Hermiticity of Hamiltonians. As an example, a non-Hermitian and non-PT-symmetric Hamiltonian with imaginary linear coordinate and linear momentum terms is constructed and analyzed in detail. The operator η+ is found, based on which, a real spectrum and a positive-definite inner product, together with the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution, are obtained for the non-Hermitian and non-PT-symmetric Hamiltonian. Moreover, this Hamiltonian turns out to be coupled when it is extended to the canonical noncommutative space with noncommutative spatial coordinate operators and noncommutative momentum operators as well. Our method is applicable to the coupled Hamiltonian. Then the first and second order noncommutative corrections of energy levels are calculated, and in particular the reality of energy spectra, the positive-definiteness of inner products, and the related properties (the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution are found not to be altered by the noncommutativity.

  5. Hermitian-Einstein metrics on holomorphic vector bundles over Hermitian manifolds

    International Nuclear Information System (INIS)

    Xi Zhang

    2004-07-01

    In this paper, we prove the long-time existence of the Hermitian-Einstein flow on a holomorphic vector bundle over a compact Hermitian (non-kaehler) manifold, and solve the Dirichlet problem for the Hermitian-Einstein equations. We also prove the existence of Hermitian-Einstein metrics for holomorphic vector bundles on a class of complete noncompact Hermitian manifolds. (author)

  6. Some remarks on quasi-Hermitian operators

    Energy Technology Data Exchange (ETDEWEB)

    Antoine, Jean-Pierre, E-mail: jean-pierre.antoine@uclouvain.be [Institut de Recherche en Mathématique et Physique, Université Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Trapani, Camillo, E-mail: camillo.trapani@unipa.it [Dipartimento di Matematica e Informatica, Università di Palermo, I-90123, Palermo (Italy)

    2014-01-15

    A quasi-Hermitian operator is an operator that is similar to its adjoint in some sense, via a metric operator, i.e., a strictly positive self-adjoint operator. Whereas those metric operators are in general assumed to be bounded, we analyze the structure generated by unbounded metric operators in a Hilbert space. Following our previous work, we introduce several generalizations of the notion of similarity between operators. Then we explore systematically the various types of quasi-Hermitian operators, bounded or not. Finally, we discuss their application in the so-called pseudo-Hermitian quantum mechanics.

  7. Dirichlet problem for Hermitian-Einstein equations over almost Hermitian manifolds

    International Nuclear Information System (INIS)

    Xi Zhang

    2004-07-01

    In this paper, we investigate the Dirichlet problem for Hermitian-Einstein equations on complex vector bundle over almost Hermitian manifolds, and we obtain the unique solubility of the Dirichlet problem for Hermitian-Einstein equations. (author)

  8. Symmetries and conservation laws in non-Hermitian field theories

    Science.gov (United States)

    Alexandre, Jean; Millington, Peter; Seynaeve, Dries

    2017-09-01

    Anti-Hermitian mass terms are considered, in addition to Hermitian ones, for P T -symmetric complex-scalar and fermionic field theories. In both cases, the Lagrangian can be written in a manifestly symmetric form in terms of the P T -conjugate variables, allowing for an unambiguous definition of the equations of motion. After discussing the resulting constraints on the consistency of the variational procedure, we show that the invariance of a non-Hermitian Lagrangian under a continuous symmetry transformation does not imply the existence of a corresponding conserved current. Conserved currents exist, but these are associated with transformations under which the Lagrangian is not invariant and which reflect the well-known interpretation of P T -symmetric theories in terms of systems with gain and loss. A formal understanding of this unusual feature of non-Hermitian theories requires a careful treatment of Noether's theorem, and we give specific examples for illustration.

  9. Physical aspects of pseudo-Hermitian and PT-symmetric quantum mechanics

    International Nuclear Information System (INIS)

    Mostafazadeh, Ali; Batal, Ahmet

    2004-01-01

    For a non-Hermitian Hamiltonian H possessing a real spectrum, we introduce a canonical orthonormal basis in which a previously introduced unitary mapping of H to a Hermitian Hamiltonian h takes a simple form. We use this basis to construct the observables O α of the quantum mechanics based on H. In particular, we introduce pseudo-Hermitian position and momentum operators and a pseudo-Hermitian quantization scheme that relates the latter to the ordinary classical position and momentum observables. These allow us to address the problem of determining the conserved probability density and the underlying classical system for pseudo-Hermitian and in particular PT-symmetric quantum systems. As a concrete example we construct the Hermitian Hamiltonian h, the physical observables O α , the localized states and the conserved probability density for the non-Hermitian PT-symmetric square well. We achieve this by employing an appropriate perturbation scheme. For this system, we conduct a comprehensive study of both the kinematical and dynamical effects of the non-Hermiticity of the Hamiltonian on various physical quantities. In particular, we show that these effects are quantum mechanical in nature and diminish in the classical limit. Our results provide an objective assessment of the physical aspects of PT-symmetric quantum mechanics and clarify its relationship with both conventional quantum mechanics and classical mechanics

  10. Hermitian harmonic maps into convex balls

    International Nuclear Information System (INIS)

    Li Zhenyang; Xi Zhang

    2004-07-01

    In this paper, we consider Hermitian harmonic maps from Hermitian manifolds into convex balls. We prove that there exist no non-trivial Hermitian harmonic maps from closed Hermitian manifolds into convex balls, and we use the heat flow method to solve the Dirichlet problem for Hermitian harmonic maps when the domain is compact Hermitian manifold with non-empty boundary. The case where the domain manifold is complete(noncompact) is also studied. (author)

  11. Sufficient conditions for positivity of non-Markovian master equations with Hermitian generators

    International Nuclear Information System (INIS)

    Wilkie, Joshua; Wong Yinmei

    2009-01-01

    We use basic physical motivations to develop sufficient conditions for positive semidefiniteness of the reduced density matrix for generalized non-Markovian integrodifferential Lindblad-Kossakowski master equations with Hermitian generators. We show that it is sufficient for the memory function to be the Fourier transform of a real positive symmetric frequency density function with certain properties. These requirements are physically motivated, and are more general and more easily checked than previously stated sufficient conditions. We also explore the decoherence dynamics numerically for some simple models using the Hadamard representation of the propagator. We show that the sufficient conditions are not necessary conditions. We also show that models exist in which the long time limit is in part determined by non-Markovian effects

  12. New quasi-exactly solvable Hermitian as well as non-Hermitian PT ...

    Indian Academy of Sciences (India)

    We start with quasi-exactly solvable (QES) Hermitian (and hence real) as well as complex P T -invariant, double sinh-Gordon potential and show that even after adding perturbation terms, the resulting potentials, in both cases, are still QES potentials. Further, by using anti-isospectral transformations, we obtain Hermitian as ...

  13. Non-Hermitian optics in atomic systems

    Science.gov (United States)

    Zhang, Zhaoyang; Ma, Danmeng; Sheng, Jiteng; Zhang, Yiqi; Zhang, Yanpeng; Xiao, Min

    2018-04-01

    A wide class of non-Hermitian Hamiltonians can possess entirely real eigenvalues when they have parity-time (PT) symmetric potentials. Recently, this family of non-Hermitian systems has attracted considerable attention in diverse areas of physics due to their extraordinary properties, especially in optical systems based on solid-state materials, such as coupled gain-loss waveguides and microcavities. Considering the desired refractive index can be effectively manipulated through atomic coherence, it is important to realize such non-Hermitian optical potentials and further investigate their distinct properties in atomic systems. In this paper, we review the recent theoretical and experimental progress of non-Hermitian optics with coherently prepared multi-level atomic configurations. The realizations of (anti-) PT symmetry with different schemes have extensively demonstrated the special optical properties of non-Hermitian optical systems with atomic coherence.

  14. Self-dual geometry of generalized Hermitian surfaces

    International Nuclear Information System (INIS)

    Arsen'eva, O E; Kirichenko, V F

    1998-01-01

    Several results on the geometry of conformally semiflat Hermitian surfaces of both classical and hyperbolic types (generalized Hermitian surfaces) are obtained. Some of these results are generalizations and clarifications of already known results in this direction due to Koda, Itoh, and other authors. They reveal some unexpected beautiful connections between such classical characteristics of conformally semiflat (generalized) Hermitian surfaces as the Einstein property, the constancy of the holomorphic sectional curvature, and so on. A complete classification of compact self-dual Hermitian RK-surfaces that are at the same time generalized Hopf manifolds is obtained. This provides a complete solution of the Chen problem in this class of Hermitian surfaces

  15. Heralded Magnetism in Non-Hermitian Atomic Systems

    Directory of Open Access Journals (Sweden)

    Tony E. Lee

    2014-10-01

    Full Text Available Quantum phase transitions are usually studied in terms of Hermitian Hamiltonians. However, cold-atom experiments are intrinsically non-Hermitian because of spontaneous decay. Here, we show that non-Hermitian systems exhibit quantum phase transitions that are beyond the paradigm of Hermitian physics. We consider the non-Hermitian XY model, which can be implemented using three-level atoms with spontaneous decay. We exactly solve the model in one dimension and show that there is a quantum phase transition from short-range order to quasi-long-range order despite the absence of a continuous symmetry in the Hamiltonian. The ordered phase has a frustrated spin pattern. The critical exponent ν can be 1 or 1/2. Our results can be seen experimentally with trapped ions, cavity QED, and atoms in optical lattices.

  16. PREFACE: 6th International Workshop on Pseudo-Hermitian Hamiltonians in Quantum Physics

    Science.gov (United States)

    Fring, Andreas; Jones, Hugh; Znojil, Miloslav

    2008-06-01

    growing community of this subject. It is, for instance, well understood that the reality of the spectrum can be attributed either to the unbroken PT-symmetry of the entire system, that is, invariance of the Hamiltonian and the corresponding wavefunctions under a simultaneous parity transformation and time reversal, or more generally to its pseudo-Hermiticity . When the spectrum is real and discrete the Hamiltonian is actually quasi-Hermitian, with a positive-definite metric operator, and can in principle be related by a similarity transformation to an isospectral Hermitian counterpart. For all approaches well-defined procedures have been developed, which allow one to construct metric operators and therefore a consistent description of the underlying quantum mechanical observables. Even though the general principles have been laid out, it remains a challenge in most concrete cases to implement the entire procedure. Solvable models in this sense, some of which may be found in this issue, remain a rare exception. Nonetheless, despite this progress some important questions are still unanswered. For instance, according to the current understanding the non-Hermitian Hamiltonian does not uniquely define the physics of the system since a meaningful metric can no longer be associated with the system in a non-trivial and unambiguous manner. A fully consistent scattering theory has also not yet been formulated. Other issues remain controversial, such as the quantum brachistochrone problem, the problem of forming a mixture between a Hermitian and non-Hermitian system, the new phenomenological possibilities of forming a kind of worm-hole effect, etc. We would like to acknowledge the financial support of the London Mathematical Society, the Institute of Physics, the Doppler Institute in Prague and the School of Engineering and Mathematical Science of City University London. We hope this special issue will be useful to the newcomer as well as to the expert in the subject. Workshop

  17. General coupled mode theory in non-Hermitian waveguides.

    Science.gov (United States)

    Xu, Jing; Chen, Yuntian

    2015-08-24

    In the presence of loss and gain, the coupled mode equation on describing the mode hybridization of various waveguides or cavities, or cavities coupled to waveguides becomes intrinsically non-Hermitian. In such non-Hermitian waveguides, the standard coupled mode theory fails. We generalize the coupled mode theory with a properly defined inner product based on reaction conservation. We apply our theory to the non-Hermitian parity-time symmetric waveguides, and obtain excellent agreement with results obtained by finite element fullwave simulations. The theory presented here is typically formulated in space to study coupling between waveguides, which can be transformed into time domain by proper reformulation to study coupling between non-Hermitian resonators. Our theory has the strength of studying non-Hermitian optical systems with inclusion of the full vector fields, thus is useful to study and design non-Hermitian devices that support asymmetric and even nonreciprocal light propagations.

  18. Pseudo-Hermitian continuous-time quantum walks

    Energy Technology Data Exchange (ETDEWEB)

    Salimi, S; Sorouri, A, E-mail: shsalimi@uok.ac.i, E-mail: a.sorouri@uok.ac.i [Department of Physics, University of Kurdistan, PO Box 66177-15175, Sanandaj (Iran, Islamic Republic of)

    2010-07-09

    In this paper we present a model exhibiting a new type of continuous-time quantum walk (as a quantum-mechanical transport process) on networks, which is described by a non-Hermitian Hamiltonian possessing a real spectrum. We call it pseudo-Hermitian continuous-time quantum walk. We introduce a method to obtain the probability distribution of walk on any vertex and then study a specific system. We observe that the probability distribution on certain vertices increases compared to that of the Hermitian case. This formalism makes the transport process faster and can be useful for search algorithms.

  19. A rule of the equilibrium of forces in the Hermitian theory of relativity

    International Nuclear Information System (INIS)

    Antoci, S.

    1987-01-01

    When the behaviour of the singularities, which are used to represent masses, charges or currents in exact solutions to the field equations of the Hermitian theory of relativity, is restricted by a no-jump rule, conditions are obtained, which determine the relative positions of masses, charges and currents. Due to these conditions the Hermitian theory of relativity appears to provide a unified description of gravitational, colour and electromagnetic forces. (author)

  20. Piecewise adiabatic following in non-Hermitian cycling

    Science.gov (United States)

    Gong, Jiangbin; Wang, Qing-hai

    2018-05-01

    The time evolution of periodically driven non-Hermitian systems is in general nonunitary but can be stable. It is hence of considerable interest to examine the adiabatic following dynamics in periodically driven non-Hermitian systems. We show in this work the possibility of piecewise adiabatic following interrupted by hopping between instantaneous system eigenstates. This phenomenon is first observed in a computational model and then theoretically explained, using an exactly solvable model, in terms of the Stokes phenomenon. In the latter case, the piecewise adiabatic following is shown to be a genuine critical behavior and the precise phase boundary in the parameter space is located. Interestingly, the critical boundary for piecewise adiabatic following is found to be unrelated to the domain for exceptional points. To characterize the adiabatic following dynamics, we also advocate a simple definition of the Aharonov-Anandan (AA) phase for nonunitary cyclic dynamics, which always yields real AA phases. In the slow driving limit, the AA phase reduces to the Berry phase if adiabatic following persists throughout the driving without hopping, but oscillates violently and does not approach any limit in cases of piecewise adiabatic following. This work exposes the rich features of nonunitary dynamics in cases of slow cycling and should stimulate future applications of nonunitary dynamics.

  1. Cotangent bundles over all the Hermitian symmetric spaces

    International Nuclear Information System (INIS)

    Arai, Masato; Baba, Kurando

    2016-01-01

    We construct the N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. In order to construct them we use the projective superspace formalism which is an N = 2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N =1 superfields, once the Kähler potentials of the base manifolds are obtained. Starting with N = 1 supersymmetric Kähler nonlinear sigma models on the Hermitian symmetric spaces, we extend them into the N = 2 supersymmetric models by using the projective superspace formalism and derive the general formula for the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. We apply to the formula for the non-compact Hermitian symmetric space E 7 /E 6 × U(1) 1 . (paper)

  2. Non-Hermitian photonics based on parity-time symmetry

    Science.gov (United States)

    Feng, Liang; El-Ganainy, Ramy; Ge, Li

    2017-12-01

    Nearly one century after the birth of quantum mechanics, parity-time symmetry is revolutionizing and extending quantum theories to include a unique family of non-Hermitian Hamiltonians. While conceptually striking, experimental demonstration of parity-time symmetry remains unexplored in quantum electronic systems. The flexibility of photonics allows for creating and superposing non-Hermitian eigenstates with ease using optical gain and loss, which makes it an ideal platform to explore various non-Hermitian quantum symmetry paradigms for novel device functionalities. Such explorations that employ classical photonic platforms not only deepen our understanding of fundamental quantum physics but also facilitate technological breakthroughs for photonic applications. Research into non-Hermitian photonics therefore advances and benefits both fields simultaneously.

  3. Hermitian self-dual quasi-abelian codes

    Directory of Open Access Journals (Sweden)

    Herbert S. Palines

    2017-12-01

    Full Text Available Quasi-abelian codes constitute an important class of linear codes containing theoretically and practically interesting codes such as quasi-cyclic codes, abelian codes, and cyclic codes. In particular, the sub-class consisting of 1-generator quasi-abelian codes contains large families of good codes. Based on the well-known decomposition of quasi-abelian codes, the characterization and enumeration of Hermitian self-dual quasi-abelian codes are given. In the case of 1-generator quasi-abelian codes, we offer necessary and sufficient conditions for such codes to be Hermitian self-dual and give a formula for the number of these codes. In the case where the underlying groups are some $p$-groups, the actual number of resulting Hermitian self-dual quasi-abelian codes are determined.

  4. Hermitian versus anti-hermitian one-matrix models and their hierarchies

    International Nuclear Information System (INIS)

    Hollowood, T.; Miramontes, L.; Pasquinucci, A.; Nappi, C.

    1992-01-01

    Building on a recent work of C. Crnkovic, M. Douglas and G. Moore, a study of multi-critical multi-cut one-matrix models and their associated sl(2, C) integrable hierarchies, is further pursued. The double-scaling limits of hermitian matrix models with different scaling ansaetze, lead to the KdV hierarchy, to the modified KdV hierarchy and part of the non-linear Schroedinger hierarchy. Instead, the anti-hermitian matrix model, in the 2-arc sector, results in the Zakharov-Shabat hierarchy, which contains both KdV and mKdV as reductions. For all the hierarchies it is found that the Virasoro constraints act on the associated τ-functions. Whereas it is known that the ZS and KdV models lead to the Virasoro constraints of an sl(2, C) vacuum, we find that the mKdV model leads to the Virasoro constraints of a highest-weight state with arbitrary conformal dimension. (orig.)

  5. Para-Hermitian and para-quaternionic manifolds

    International Nuclear Information System (INIS)

    Ivanov, S.; Zamkovoy, S.

    2003-10-01

    A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S 1 x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)

  6. Para-Hermitian and para-quaternionic manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria) and Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Zamkovoy, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria)

    2003-10-01

    A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S{sup 1} x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)

  7. Some applicationS of non-Hermitian operators in quantum mechanics and quantum field theory

    International Nuclear Information System (INIS)

    Recami, E.; Rodrigues, W.A. Jr.; Smrz, P.

    1983-01-01

    Due to the possibility of rephrasing it in terms of Lie-admissible algebras, some work done in the past in collaboration with A., Agodi, M., Baldo and V.S., Olkhovsky is here reported. Such work led to the introduction of non-Hermitian operators in (classical and relativistic) quantum theory. In particular: (i) the association of unstable states (decaying 'Resonances') with the eigenvectors of non-Hermitian hamiltonians; (ii) the problem of the four position operators for relativistic spin-zero particles are dealth with

  8. Balanced Hermitian metrics from SU(2)-structures

    International Nuclear Information System (INIS)

    Fernandez, M.; Tomassini, A.; Ugarte, L.; Villacampa, R.

    2009-01-01

    We study the intrinsic geometrical structure of hypersurfaces in six-manifolds carrying a balanced Hermitian SU(3)-structure, which we call balanced SU(2)-structure. We provide sufficient conditions, in terms of suitable evolution equations, which imply that a five-manifold with such structure can be isometrically embedded as a hypersurface in a balanced Hermitian SU(3)-manifold. Any five-dimensional compact nilmanifold has an invariant balanced SU(2)-structure, and we show how some of them can be evolved to give new explicit examples of balanced Hermitian SU(3)-structures. Moreover, for n=3,4, we present examples of compact solvmanifolds endowed with a balanced SU(n)-structure such that the corresponding Bismut connection has holonomy equal to SU(n)

  9. Various scattering properties of a new PT-symmetric non-Hermitian potential

    International Nuclear Information System (INIS)

    Ghatak, Ananya; Mandal, Raka Dona Ray; Mandal, Bhabani Prasad

    2013-01-01

    We complexify a 1-d potential V(x)=V 0 cosh 2 μ(tanh[(x−μd)/d]+tanh(μ)) 2 which exhibits bound, reflecting and free states to study various properties of a non-Hermitian system. This potential turns out a PT-symmetric non-Hermitian potential when one of the parameters (μ,d) becomes imaginary. For the case of μ→iμ, we have an entire real bound state spectrum. Explicit scattering states are constructed to show reciprocity at certain discrete values of energy even though the potential is not parity symmetric. Coexistence of deep energy minima of transmissivity with the multiple spectral singularities (MSS) is observed. We further show that this potential becomes invisible from the left (or right) at certain discrete energies. The penetrating states in the other case (d→id) are always reciprocal even though it is PT-invariant and no spectral singularity (SS) is present in this case. The presence of MSS and reflectionlessness is also discussed for the free states in the later case. -- Highlights: •Existence of multiple spectral singularities (MSS) in PT-symmetric non-Hermitian system is shown. •Reciprocity is restored at discrete positive energies even for parity non-invariant complex system. •Co-existence of MSS with deep energy minima of transitivity is obtained. •Possibilities of both unidirectional and bidirectional invisibility are explored for a non-Hermitian system. •Penetrating states are shown to be reciprocal for all energies for PT-symmetric system

  10. New quasi-exactly solvable Hermitian as well as non-Hermitian PT ...

    Indian Academy of Sciences (India)

    Abstract. We start with quasi-exactly solvable (QES) Hermitian (and hence real) as ... the time reversal transformation t → −t and further, one replaces i → −i. One can ..... F M Fernandez, R Guardiola, J Ros and M Znojil, J. Phys. A32, 3105 ...

  11. Decoding Hermitian Codes with Sudan's Algorithm

    DEFF Research Database (Denmark)

    Høholdt, Tom; Nielsen, Rasmus Refslund

    1999-01-01

    We present an efficient implementation of Sudan's algorithm for list decoding Hermitian codes beyond half the minimum distance. The main ingredients are an explicit method to calculate so-called increasing zero bases, an efficient interpolation algorithm for finding the Q-polynomial, and a reduct......We present an efficient implementation of Sudan's algorithm for list decoding Hermitian codes beyond half the minimum distance. The main ingredients are an explicit method to calculate so-called increasing zero bases, an efficient interpolation algorithm for finding the Q...

  12. Multiple Meixner polynomials and non-Hermitian oscillator Hamiltonians

    International Nuclear Information System (INIS)

    Ndayiragije, F; Van Assche, W

    2013-01-01

    Multiple Meixner polynomials are polynomials in one variable which satisfy orthogonality relations with respect to r > 1 different negative binomial distributions (Pascal distributions). There are two kinds of multiple Meixner polynomials, depending on the selection of the parameters in the negative binomial distribution. We recall their definition and some formulas and give generating functions and explicit expressions for the coefficients in the nearest neighbor recurrence relation. Following a recent construction of Miki, Tsujimoto, Vinet and Zhedanov (for multiple Meixner polynomials of the first kind), we construct r > 1 non-Hermitian oscillator Hamiltonians in r dimensions which are simultaneously diagonalizable and for which the common eigenstates are expressed in terms of multiple Meixner polynomials of the second kind. (paper)

  13. Non-Hermitian spin chains with inhomogeneous coupling

    Energy Technology Data Exchange (ETDEWEB)

    Bytsko, Andrei G. [Rossijskaya Akademiya Nauk, St. Petersburg (Russian Federation). Inst. Matematiki; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie

    2009-11-15

    An open U{sub q}(sl{sub 2})-invariant spin chain of spin S and length N with inhomogeneous coupling is investigated as an example of a non-Hermitian (quasi-Hermitian) model. For several particular cases of such a chain, the ranges of the deformation parameter {gamma} are determined for which the spectrum of the model is real. For a certain range of {gamma}, a universal metric operator is constructed and thus the quasi-Hermiticity of the model is established. The constructed metric operator is non-dynamical, its structure is determined only by the symmetry of the model. The results apply, in particular, to all known homogeneous U{sub q}(sl{sub 2})-invariant integrable spin chains with nearest-neighbour interaction. In addition, the most general form of a metric operator for a quasi-Hermitian operator in finite dimensional space is discussed. (orig.)

  14. Non-Hermitian Heisenberg representation

    Czech Academy of Sciences Publication Activity Database

    Znojil, Miloslav

    2015-01-01

    Roč. 379, č. 36 (2015), s. 2013-2017 ISSN 0375-9601 Institutional support: RVO:61389005 Keywords : quantum mechanics * Non-Hermitian representation of observables * Generalized Heisenberg equations Subject RIV: BE - Theoretical Physics Impact factor: 1.677, year: 2015

  15. Moyal products-a new perspective on quasi-Hermitian quantum mechanics

    International Nuclear Information System (INIS)

    Scholtz, F G; Geyer, H B

    2006-01-01

    The rationale for introducing non-Hermitian Hamiltonians and other observables is reviewed and open issues identified. We present a new approach based on Moyal products to compute the metric for quasi-Hermitian systems. This approach is not only an efficient method of computation, but also suggests a new perspective on quasi-Hermitian quantum mechanics which invites further exploration. In particular, we present some first results which link the Berry connection and curvature to non-perturbative properties and the metric

  16. Various scattering properties of a new PT-symmetric non-Hermitian potential

    Energy Technology Data Exchange (ETDEWEB)

    Ghatak, Ananya, E-mail: gananya04@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Mandal, Raka Dona Ray, E-mail: rakad.ray@gmail.com [Department of Physics, Rajghat Besant School, Varanasi-221001 (India); Mandal, Bhabani Prasad, E-mail: bhabani.mandal@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India)

    2013-09-15

    We complexify a 1-d potential V(x)=V{sub 0}cosh{sup 2}μ(tanh[(x−μd)/d]+tanh(μ)){sup 2} which exhibits bound, reflecting and free states to study various properties of a non-Hermitian system. This potential turns out a PT-symmetric non-Hermitian potential when one of the parameters (μ,d) becomes imaginary. For the case of μ→iμ, we have an entire real bound state spectrum. Explicit scattering states are constructed to show reciprocity at certain discrete values of energy even though the potential is not parity symmetric. Coexistence of deep energy minima of transmissivity with the multiple spectral singularities (MSS) is observed. We further show that this potential becomes invisible from the left (or right) at certain discrete energies. The penetrating states in the other case (d→id) are always reciprocal even though it is PT-invariant and no spectral singularity (SS) is present in this case. The presence of MSS and reflectionlessness is also discussed for the free states in the later case. -- Highlights: •Existence of multiple spectral singularities (MSS) in PT-symmetric non-Hermitian system is shown. •Reciprocity is restored at discrete positive energies even for parity non-invariant complex system. •Co-existence of MSS with deep energy minima of transitivity is obtained. •Possibilities of both unidirectional and bidirectional invisibility are explored for a non-Hermitian system. •Penetrating states are shown to be reciprocal for all energies for PT-symmetric system.

  17. Infinite families of (non)-Hermitian Hamiltonians associated with exceptional Xm Jacobi polynomials

    International Nuclear Information System (INIS)

    Midya, Bikashkali; Roy, Barnana

    2013-01-01

    Using an appropriate change of variable, the Schrödinger equation is transformed into a second-order differential equation satisfied by recently discovered Jacobi-type X m exceptional orthogonal polynomials. This facilitates the derivation of infinite families of exactly solvable Hermitian as well as non-Hermitian trigonometric Scarf potentials and a finite number of Hermitian and an infinite number of non-Hermitian PT-symmetric hyperbolic Scarf potentials. The bound state solutions of all these potentials are associated with the aforesaid exceptional orthogonal polynomials. These infinite families of potentials are shown to be extensions of the conventional trigonometric and hyperbolic Scarf potentials by the addition of some rational terms characterized by the presence of classical Jacobi polynomials. All the members of a particular family of these ‘rationally extended polynomial-dependent’ potentials have the same energy spectrum and possess translational shape-invariant symmetry. The obtained non-Hermitian trigonometric Scarf potentials are shown to be quasi-Hermitian in nature ensuring the reality of the associated energy spectra. (paper)

  18. 15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics

    CERN Document Server

    Passante, Roberto; Trapani, Camillo

    2016-01-01

    This book presents the Proceedings of the 15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics, held in Palermo, Italy, from 18 to 23 May 2015. Non-Hermitian operators, and non-Hermitian Hamiltonians in particular, have recently received considerable attention from both the mathematics and physics communities. There has been a growing interest in non-Hermitian Hamiltonians in quantum physics since the discovery that PT-symmetric Hamiltonians can have a real spectrum and thus a physical relevance. The main subjects considered in this book include: PT-symmetry in quantum physics, PT-optics, Spectral singularities and spectral techniques, Indefinite-metric theories, Open quantum systems, Krein space methods, and Biorthogonal systems and applications. The book also provides a summary of recent advances in pseudo-Hermitian Hamiltonians and PT-symmetric Hamiltonians, as well as their applications in quantum physics and in the theory of open quantum systems.

  19. Analytical results for non-Hermitian parity–time-symmetric and ...

    Indian Academy of Sciences (India)

    Abstract. We investigate both the non-Hermitian parity–time-(PT-)symmetric and Hermitian asymmetric volcano potentials, and present the analytical solution in terms of the confluent Heun function. Under certain special conditions, the confluent Heun function can be terminated as a polynomial, thereby leading to certain ...

  20. Theory of superconductivity with non-Hermitian and parity-time reversal symmetric Cooper pairing symmetry

    Science.gov (United States)

    Ghatak, Ananya; Das, Tanmoy

    2018-01-01

    Recently developed parity (P ) and time-reversal (T ) symmetric non-Hermitian systems govern a rich variety of new and characteristically distinct physical properties, which may or may not have a direct analog in their Hermitian counterparts. We study here a non-Hermitian, PT -symmetric superconducting Hamiltonian that possesses a real quasiparticle spectrum in the PT -unbroken region of the Brillouin zone. Within a single-band mean-field theory, we find that real quasiparticle energies are possible when the superconducting order parameter itself is either Hermitian or anti-Hermitian. Within the corresponding Bardeen-Cooper-Schrieffer (BCS) theory, we find that several properties are characteristically distinct and novel in the non-Hermitian pairing case than its Hermitian counterpart. One of our significant findings is that while a Hermitian superconductor gives a second-order phase transition, the non-Hermitian one produces a robust first-order phase transition. The corresponding thermodynamic properties and the Meissner effect are also modified accordingly. Finally, we discuss how such a PT -symmetric pairing can emerge from an antisymmetric potential, such as the Dzyloshinskii-Moriya interaction, but with an external bath, or complex potential, among others.

  1. Modified Hermitian treatment of Dyson boson expansion theory

    International Nuclear Information System (INIS)

    Kajiyama, Atsushi

    2009-01-01

    The Hermitian treatment of the Dyson-type boson expansion theory is reinvestigated with the aid of small-parameter expansion. A naive application of the Hermitization formula sometimes yields an unrealistic phase that spoils the conventional treatment. The complementary use of another formula having the form of the arithmetic mean can avoid that problem. This modification will improve the accuracy of the Hermitian treatment. (author)

  2. Numerical solution to the hermitian Yang-Mills equation on the Fermat quintic

    International Nuclear Information System (INIS)

    Douglas, Michael R.; Karp, Robert L.; Lukic, Sergio; Reinbacher, Rene

    2007-01-01

    We develop an iterative method for finding solutions to the hermitian Yang-Mills equation on stable holomorphic vector bundles, following ideas recently developed by Donaldson. As illustrations, we construct numerically the hermitian Einstein metrics on the tangent bundle and a rank three vector bundle on P 2 . In addition, we find a hermitian Yang-Mills connection on a stable rank three vector bundle on the Fermat quintic

  3. Krylov Subspace Methods for Complex Non-Hermitian Linear Systems. Thesis

    Science.gov (United States)

    Freund, Roland W.

    1991-01-01

    We consider Krylov subspace methods for the solution of large sparse linear systems Ax = b with complex non-Hermitian coefficient matrices. Such linear systems arise in important applications, such as inverse scattering, numerical solution of time-dependent Schrodinger equations, underwater acoustics, eddy current computations, numerical computations in quantum chromodynamics, and numerical conformal mapping. Typically, the resulting coefficient matrices A exhibit special structures, such as complex symmetry, or they are shifted Hermitian matrices. In this paper, we first describe a Krylov subspace approach with iterates defined by a quasi-minimal residual property, the QMR method, for solving general complex non-Hermitian linear systems. Then, we study special Krylov subspace methods designed for the two families of complex symmetric respectively shifted Hermitian linear systems. We also include some results concerning the obvious approach to general complex linear systems by solving equivalent real linear systems for the real and imaginary parts of x. Finally, numerical experiments for linear systems arising from the complex Helmholtz equation are reported.

  4. Improved Power Decoding of One-Point Hermitian Codes

    DEFF Research Database (Denmark)

    Puchinger, Sven; Bouw, Irene; Rosenkilde, Johan Sebastian Heesemann

    2017-01-01

    We propose a new partial decoding algorithm for one-point Hermitian codes that can decode up to the same number of errors as the Guruswami–Sudan decoder. Simulations suggest that it has a similar failure probability as the latter one. The algorithm is based on a recent generalization of the power...... decoding algorithm for Reed–Solomon codes and does not require an expensive root-finding step. In addition, it promises improvements for decoding interleaved Hermitian codes....

  5. A fast, preconditioned conjugate gradient Toeplitz solver

    Science.gov (United States)

    Pan, Victor; Schrieber, Robert

    1989-01-01

    A simple factorization is given of an arbitrary hermitian, positive definite matrix in which the factors are well-conditioned, hermitian, and positive definite. In fact, given knowledge of the extreme eigenvalues of the original matrix A, an optimal improvement can be achieved, making the condition numbers of each of the two factors equal to the square root of the condition number of A. This technique is to applied to the solution of hermitian, positive definite Toeplitz systems. Large linear systems with hermitian, positive definite Toeplitz matrices arise in some signal processing applications. A stable fast algorithm is given for solving these systems that is based on the preconditioned conjugate gradient method. The algorithm exploits Toeplitz structure to reduce the cost of an iteration to O(n log n) by applying the fast Fourier Transform to compute matrix-vector products. Matrix factorization is used as a preconditioner.

  6. Quantum entropy of systems described by non-Hermitian Hamiltonians

    International Nuclear Information System (INIS)

    Sergi, Alessandro; Zloshchastiev, Konstantin G

    2016-01-01

    We study the quantum entropy of systems that are described by general non-Hermitian Hamiltonians, including those which can model the effects of sinks or sources. We generalize the von Neumann entropy to the non-Hermitian case and find that one needs both the normalized and non-normalized density operators in order to properly describe irreversible processes. It turns out that such a generalization monitors the onset of disorder in quantum dissipative systems. We give arguments for why one can consider the generalized entropy as the informational entropy describing the flow of information between the system and the bath. We illustrate the theory by explicitly studying few simple models, including tunneling systems with two energy levels and non-Hermitian detuning. (paper: quantum statistical physics, condensed matter, integrable systems)

  7. Supersymmetric Extension of Non-Hermitian su(2 Hamiltonian and Supercoherent States

    Directory of Open Access Journals (Sweden)

    Omar Cherbal

    2010-12-01

    Full Text Available A new class of non-Hermitian Hamiltonians with real spectrum, which are written as a real linear combination of su(2 generators in the form H=ωJ_3+αJ_−+βJ_+, α≠β, is analyzed. The metrics which allows the transition to the equivalent Hermitian Hamiltonian is established. A pseudo-Hermitian supersymmetic extension of such Hamiltonians is performed. They correspond to the pseudo-Hermitian supersymmetric systems of the boson-phermion oscillators. We extend the supercoherent states formalism to such supersymmetic systems via the pseudo-unitary supersymmetric displacement operator method. The constructed family of these supercoherent states consists of two dual subfamilies that form a bi-overcomplete and bi-normal system in the boson-phermion Fock space. The states of each subfamily are eigenvectors of the boson annihilation operator and of one of the two phermion lowering operators.

  8. Faster than Hermitian Quantum Mechanics

    International Nuclear Information System (INIS)

    Bender, Carl M.; Brody, Dorje C.; Jones, Hugh F.; Meister, Bernhard K.

    2007-01-01

    Given an initial quantum state vertical bar ψ I > and a final quantum state vertical bar ψ F >, there exist Hamiltonians H under which vertical bar ψ I > evolves into vertical bar ψ F >. Consider the following quantum brachistochrone problem: subject to the constraint that the difference between the largest and smallest eigenvalues of H is held fixed, which H achieves this transformation in the least time τ? For Hermitian Hamiltonians τ has a nonzero lower bound. However, among non-Hermitian PT-symmetric Hamiltonians satisfying the same energy constraint, τ can be made arbitrarily small without violating the time-energy uncertainty principle. This is because for such Hamiltonians the path from vertical bar ψ I > to vertical bar ψ F > can be made short. The mechanism described here is similar to that in general relativity in which the distance between two space-time points can be made small if they are connected by a wormhole. This result may have applications in quantum computing

  9. Non-Hermitian Extensions of Wishart Random Matrix Ensembles

    International Nuclear Information System (INIS)

    Akemann, G.

    2011-01-01

    We briefly review the solution of three ensembles of non-Hermitian random matrices generalizing the Wishart-Laguerre (also called chiral) ensembles. These generalizations are realized as Gaussian two-matrix models, where the complex eigenvalues of the product of the two independent rectangular matrices are sought, with the matrix elements of both matrices being either real, complex or quaternion real. We also present the more general case depending on a non-Hermiticity parameter, that allows us to interpolate between the corresponding three Hermitian Wishart ensembles with real eigenvalues and the maximally non-Hermitian case. All three symmetry classes are explicitly solved for finite matrix size N x M for all complex eigenvalue correlations functions (and real or mixed correlations for real matrix elements). These are given in terms of the corresponding kernels built from orthogonal or skew-orthogonal Laguerre polynomials in the complex plane. We then present the corresponding three Bessel kernels in the complex plane in the microscopic large-N scaling limit at the origin, both at weak and strong non-Hermiticity with M - N ≥ 0 fixed. (author)

  10. Geometry of quantal adiabatic evolution driven by a non-Hermitian Hamiltonian

    International Nuclear Information System (INIS)

    Wu Zhaoyan; Yu Ting; Zhou Hongwei

    1994-01-01

    It is shown by using a counter example, which is exactly solvable, that the quantal adiabatic theorem does not generally hold for a non-Hermitian driving Hamiltonian, even if it varies extremely slowly. The condition for the quantal adiabatic theorem to hold for non-Hermitian driving Hamiltonians is given. The adiabatic evolutions driven by a non-Hermitian Hamiltonian provide examples of a new geometric structure, that is the vector bundle in which the inner product of two parallelly transported vectors generally changes. A new geometric concept, the attenuation tensor, is naturally introduced to describe the decay or flourish of the open quantum system. It is constructed in terms of the spectral projector of the Hamiltonian. (orig.)

  11. Supersymmetry and cotangent bundle over non-compact exceptional Hermitian symmetric space

    International Nuclear Information System (INIS)

    Arai, Masato; Baba, Kurando

    2015-01-01

    We construct N=2 supersymmetric nonlinear sigma models on the cotangent bundles over the non-compact exceptional Hermitian symmetric spaces M=E 6(−14) /SO(10)×U(1) and E 7(−25) /E 6 ×U(1). In order to construct them we use the projective superspace formalism which is an N=2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N=2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N=1 superfields, once the Kähler potentials of the base manifolds are obtained. We derive the N=1 supersymmetric nonlinear sigma models on the Kähler manifolds M. Then we extend them into the N=2 supersymmetric models with the use of the result in arXiv:1211.1537 developed in the projective superspace formalism. The resultant models are the N=2 supersymmetric nonlinear sigma models on the cotangent bundles over the Hermitian symmetric spaces M. In this work we complete constructing the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces.

  12. Designing non-Hermitian dynamics for conservative state evolution on the Bloch sphere

    Science.gov (United States)

    Yu, Sunkyu; Piao, Xianji; Park, Namkyoo

    2018-03-01

    An evolution on the Bloch sphere is the fundamental state transition, including optical polarization controls and qubit operations. Conventional evolution of a polarization state or qubit is implemented within a closed system that automatically satisfies energy conservation from the Hermitian formalism. Although particular forms of static non-Hermitian Hamiltonians, such as parity-time-symmetric Hamiltonians, allow conservative states in an open system, the criteria for the energy conservation in a dynamical open system have not been fully explored. Here, we derive the condition of conservative state evolution in open-system dynamics and its inverse design method, by developing the non-Hermitian modification of the Larmor precession equation. We show that the geometrically designed locus on the Bloch sphere can be realized by different forms of dynamics, leading to the isolocus family of non-Hermitian dynamics. This increased degree of freedom allows the complementary phenomena of error-robust and highly sensitive evolutions on the Bloch sphere, which could be applicable to stable polarizers, quantum gates, and optimized sensors in dynamical open systems.

  13. Special issue on quantum physics with non-Hermitian operators Special issue on quantum physics with non-Hermitian operators

    Science.gov (United States)

    Bender, Carl M.; Fring, Andreas; Guenther, Uwe; Jones, Hugh F.

    2012-01-01

    This is a call for contributions to a special issue of Journal of Physics A: Mathematical and Theoretical dedicated to quantum physics with non-Hermitian operators. The main motivation behind this special issue is to gather together recent results, developments and open problems in this rapidly evolving field of research in a single comprehensive volume. We expect that such a special issue will become a valuable reference for the broad scientific community working in mathematical and theoretical physics. The issue will be open to all contributions containing new results on non-Hermitian theories which are explicitly PT-symmetric and/or pseudo-Hermitian or quasi-Hermitian. The main novelties in the past years in this area have been many experimental observations, realizations, and applications of PT symmetric Hamiltonians in optics and microwave cavities. We especially invite contributions on the theoretical interpretations of these recent PT-symmetric experiments and on theoretical proposals for new experiments. Editorial policy The Guest Editors for this issue are Carl Bender, Andreas Fring, Uwe Guenther and Hugh Jones. The areas and topics for this issue include, but are not limited to: spectral problems novel properties of complex optical potentials PT-symmetry related threshold lasers and spectral singularities construction of metric operators scattering theory supersymmetric theories Lie algebraic and Krein-space methods random matrix models classical and semi-classical models exceptional points in model systems operator theoretic approaches microwave cavities aspects of integrability and exact solvability field theories with indefinite metric All contributions will be refereed and processed according to the usual procedure of the journal. Papers should report original and significant research that has not already been published. Guidelines for preparation of contributions The deadline for contributed papers will be 31 March 2012. This deadline will allow the

  14. Pseudospectra in non-Hermitian quantum mechanics

    Science.gov (United States)

    Krejčiřík, D.; Siegl, P.; Tater, M.; Viola, J.

    2015-10-01

    We propose giving the mathematical concept of the pseudospectrum a central role in quantum mechanics with non-Hermitian operators. We relate pseudospectral properties to quasi-Hermiticity, similarity to self-adjoint operators, and basis properties of eigenfunctions. The abstract results are illustrated by unexpected wild properties of operators familiar from PT -symmetric quantum mechanics.

  15. Higher genus correlators from the hermitian one-matrix model

    International Nuclear Information System (INIS)

    Ambjoern, J.; Chekhov, L.; Makeenko, Yu.

    1992-01-01

    We develop an iterative algorithm for the genus expansion of the hermitian NxN one-matrix model (is the Penner model in an external field). By introducing moments of the external field, we prove that the genus g contribution to the m-loop correlator depends only on 3g-2+m lower moments (3g-2 for the partition function). We present the explicit results for the partition function and the one-loop correlator in genus one. We compare the correlators for the hermitian one-matrix model with those at zero momenta for c=1 CFT and show an agreement of the one-loop correlators for genus zero. (orig.)

  16. Factorisations for partition functions of random Hermitian matrix models

    International Nuclear Information System (INIS)

    Jackson, D.M.; Visentin, T.I.

    1996-01-01

    The partition function Z N , for Hermitian-complex matrix models can be expressed as an explicit integral over R N , where N is a positive integer. Such an integral also occurs in connection with random surfaces and models of two dimensional quantum gravity. We show that Z N can be expressed as the product of two partition functions, evaluated at translated arguments, for another model, giving an explicit connection between the two models. We also give an alternative computation of the partition function for the φ 4 -model.The approach is an algebraic one and holds for the functions regarded as formal power series in the appropriate ring. (orig.)

  17. Critical statistics for non-Hermitian matrices

    International Nuclear Information System (INIS)

    Garcia-Garcia, A.M.; Verbaarschot, J.J.M.; Nishigaki, S.M.

    2002-01-01

    We introduce a generalized ensemble of non-Hermitian matrices interpolating between the Gaussian Unitary Ensemble, the Ginibre ensemble, and the Poisson ensemble. The joint eigenvalue distribution of this model is obtained by means of an extension of the Itzykson-Zuber formula to general complex matrices. Its correlation functions are studied both in the case of weak non-Hermiticity and in the case of strong non-Hermiticity. In the weak non-Hermiticity limit we show that the spectral correlations in the bulk of the spectrum display critical statistics: the asymptotic linear behavior of the number variance is already approached for energy differences of the order of the eigenvalue spacing. To lowest order, its slope does not depend on the degree of non-Hermiticity. Close the edge, the spectral correlations are similar to the Hermitian case. In the strong non-Hermiticity limit the crossover behavior from the Ginibre ensemble to the Poisson ensemble first appears close to the surface of the spectrum. Our model may be relevant for the description of the spectral correlations of an open disordered system close to an Anderson transition

  18. Constant-intensity waves and their modulation instability in non-Hermitian potentials

    Science.gov (United States)

    Makris, K. G.; Musslimani, Z. H.; Christodoulides, D. N.; Rotter, S.

    2015-07-01

    In all of the diverse areas of science where waves play an important role, one of the most fundamental solutions of the corresponding wave equation is a stationary wave with constant intensity. The most familiar example is that of a plane wave propagating in free space. In the presence of any Hermitian potential, a wave's constant intensity is, however, immediately destroyed due to scattering. Here we show that this fundamental restriction is conveniently lifted when working with non-Hermitian potentials. In particular, we present a whole class of waves that have constant intensity in the presence of linear as well as of nonlinear inhomogeneous media with gain and loss. These solutions allow us to study the fundamental phenomenon of modulation instability in an inhomogeneous environment. Our results pose a new challenge for the experiments on non-Hermitian scattering that have recently been put forward.

  19. Hermitian Mindlin Plate Wavelet Finite Element Method for Load Identification

    Directory of Open Access Journals (Sweden)

    Xiaofeng Xue

    2016-01-01

    Full Text Available A new Hermitian Mindlin plate wavelet element is proposed. The two-dimensional Hermitian cubic spline interpolation wavelet is substituted into finite element functions to construct frequency response function (FRF. It uses a system’s FRF and response spectrums to calculate load spectrums and then derives loads in the time domain via the inverse fast Fourier transform. By simulating different excitation cases, Hermitian cubic spline wavelets on the interval (HCSWI finite elements are used to reverse load identification in the Mindlin plate. The singular value decomposition (SVD method is adopted to solve the ill-posed inverse problem. Compared with ANSYS results, HCSWI Mindlin plate element can accurately identify the applied load. Numerical results show that the algorithm of HCSWI Mindlin plate element is effective. The accuracy of HCSWI can be verified by comparing the FRF of HCSWI and ANSYS elements with the experiment data. The experiment proves that the load identification of HCSWI Mindlin plate is effective and precise by using the FRF and response spectrums to calculate the loads.

  20. Spontaneous symmetry breaking and the Goldstone theorem in non-Hermitian field theories arXiv

    CERN Document Server

    Alexandre, Jean; Millington, Peter; Seynaeve, Dries

    We demonstrate the extension to PT-symmetric field theories of the Goldstone theorem, confirming that the spontaneous appearance of a field vacuum expectation value via minimisation of the effective potential in a non-Hermitian model is accompanied by a massless scalar boson. Laying a basis for our analysis, we first show how the conventional quantisation of the path-integral formulation of quantum field theory can be extended consistently to a non-Hermitian model by considering PT conjugation instead of Hermitian conjugation. The extension of the Goldstone theorem to a PT-symmetric field theory is made possible by the existence of a conserved current that does not, however, correspond to a symmetry of the non-Hermitian Lagrangian. In addition to extending the proof of the Goldstone theorem to a PT-symmetric theory, we exhibit a specific example in which we verify the existence of a massless boson at the tree and one-loop levels.

  1. Resolutions of Identity for Some Non-Hermitian Hamiltonians. II. Proofs

    Directory of Open Access Journals (Sweden)

    Andrey V. Sokolov

    2011-12-01

    Full Text Available This part is a continuation of the Part I where we built resolutions of identity for certain non-Hermitian Hamiltonians constructed of biorthogonal sets of their eigen- and associated functions for the spectral problem defined on entire axis. Non-Hermitian Hamiltonians under consideration are taken with continuous spectrum and the following cases are examined: an exceptional point of arbitrary multiplicity situated on a boundary of continuous spectrum and an exceptional point situated inside of continuous spectrum. In the present work the rigorous proofs are given for the resolutions of identity in both cases.

  2. Astrophysical evidence for the non-Hermitian but PT-symmetric Hamiltonian of conformal gravity

    International Nuclear Information System (INIS)

    Mannheim, P.D.

    2013-01-01

    In this review we discuss the connection between two seemingly disparate topics, macroscopic gravity on astrophysical scales and Hamiltonians that are not Hermitian but PT symmetric on microscopic ones. In particular we show that the quantum-mechanical unitarity problem of the fourth-order derivative conformal gravity theory is resolved by recognizing that the scalar product appropriate to the theory is not the Dirac norm associated with a Hermitian Hamiltonian but is instead the norm associated with a non-Hermitian but PT-symmetric Hamiltonian. Moreover, the fourth-order theory Hamiltonian is not only not Hermitian, it is not even diagonalizable, being of Jordan-block form. With PT symmetry we establish that conformal gravity is consistent at the quantum-mechanical level. In consequence, we can apply the theory to data, to find that the theory is capable of naturally accounting for the systematics of the rotation curves of a large and varied sample of 138 spiral galaxies without any need for dark matter. The success of the fits provides evidence for the relevance of non-diagonalizable but PT-symmetric Hamiltonians to physics. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Pseudo-Hermitian description of PT-symmetric systems defined on a complex contour

    International Nuclear Information System (INIS)

    Mostafazadeh, Ali

    2005-01-01

    We describe a method that allows for a practical application of the theory of pseudo-Hermitian operators to PT-symmetric systems defined on a complex contour. We apply this method to study the Hamiltonians H = p 2 + x 2 (ix) ν with ν ε (-2, ∞) that are defined along the corresponding anti-Stokes lines. In particular, we reveal the intrinsic non-Hermiticity of H for the cases that ν is an even integer, so that H p 2 ± x 2+ν , and give a proof of the discreteness of the spectrum of H for all ν ε (-2, ∞). Furthermore, we study the consequences of defining a square-well Hamiltonian on a wedge-shaped complex contour. This yields a PT-symmetric system with a finite number of real eigenvalues. We present a comprehensive analysis of this system within the framework of pseudo-Hermitian quantum mechanics. We also outline a direct pseudo-Hermitian treatment of PT-symmetric systems defined on a complex contour which clarifies the underlying mathematical structure of the formulation of PT-symmetric quantum mechanics based on the charge-conjugation operator. Our results provide conclusive evidence that pseudo-Hermitian quantum mechanics provides a complete description of general PT-symmetric systems regardless of whether they are defined along the real line or a complex contour

  4. Parity-time symmetry meets photonics: A new twist in non-Hermitian optics

    Science.gov (United States)

    Longhi, Stefano

    2017-12-01

    In the past decade, the concept of parity-time (PT) symmetry, originally introduced in non-Hermitian extensions of quantum mechanical theories, has come into thinking of photonics, providing a fertile ground for studying, observing, and utilizing some of the peculiar aspects of PT symmetry in optics. Together with related concepts of non-Hermitian physics of open quantum systems, such as non-Hermitian degeneracies (exceptional points) and spectral singularities, PT symmetry represents one among the most fruitful ideas introduced in optics in the past few years. Judicious tailoring of optical gain and loss in integrated photonic structures has emerged as a new paradigm in shaping the flow of light in unprecedented ways, with major applications encompassing laser science and technology, optical sensing, and optical material engineering. In this perspective, I review some of the main achievements and emerging areas of PT -symmetric and non-Hermtian photonics, and provide an outline of challenges and directions for future research in one of the fastest growing research area of photonics.

  5. Higher genus correlators for the hermitian matrix model with multiple cuts

    International Nuclear Information System (INIS)

    Akemann, G.

    1996-01-01

    An iterative scheme is set up for solving the loop equation of the hermitian one-matrix model with a multi-cut structure. Explicit results are presented for genus one for an arbitrary but finite number of cuts. Due to the complicated form of the boundary conditions, the loop correlators now contain elliptic integrals. This demonstrates the existence of new universality classes for the hermitian matrix model. The two-cut solution is investigated in more detail, including the double scaling limit. It is shown that in special cases it differs from the known continuum solution with one cut. (orig.)

  6. On the subfield subcodes of Hermitian codes

    DEFF Research Database (Denmark)

    Pinero, Fernando; Janwa, Heeralal

    2014-01-01

    We present a fast algorithm using Gröbner basis to compute the dimensions of subfield subcodes of Hermitian codes. With these algorithms we are able to compute the exact values of the dimension of all subfield subcodes up to q ≤ 32 and length up to 215. We show that some of the subfield subcodes ...

  7. Pseudo-Hermitian quantum dynamics of tachyonic spin-1/2 particles

    International Nuclear Information System (INIS)

    Jentschura, U D; Wundt, B J

    2012-01-01

    We investigate the spinor solutions, the spectrum and the symmetry properties of a matrix-valued wave equation whose plane-wave solutions satisfy the superluminal (tachyonic) dispersion relation E 2 = p-vector 2 - m 2 , where E is the energy, p-vector is the spatial momentum and m is the mass of the particle. The equation reads (iγ μ  ∂ μ − γ 5  m)ψ = 0, where γ 5 is the fifth current. The tachyonic equation is shown to be CP invariant and T invariant. The tachyonic Hamiltonian breaks parity and is non-Hermitian but fulfils the pseudo-Hermitian property H 5 ( r-vector ) = P H + 5 (- r-vector ) P -1 =P H + 5 ( r-vector ) P -1 , where P is the parity matrix and P is the full parity transformation. The energy eigenvalues and eigenvectors describe a continuous spectrum of plane-wave solutions (which correspond to real eigenvalues for | p-vector |≥m) and evanescent waves, which constitute resonances and anti-resonances with complex-conjugate pairs of resonance eigenvalues (for | p-vector | 5 . This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

  8. Self-hybridization within non-Hermitian localized plasmonic systems

    Science.gov (United States)

    Lourenço-Martins, Hugo; Das, Pabitra; Tizei, Luiz H. G.; Weil, Raphaël; Kociak, Mathieu

    2018-04-01

    The orthogonal eigenmodes are well-defined solutions of Hermitian equations describing many physical situations from quantum mechanics to acoustics. However, a large variety of non-Hermitian problems, including gravitational waves close to black holes or leaky electromagnetic cavities, require the use of a bi-orthogonal eigenbasis with consequences challenging our physical understanding1-4. The need to compensate for energy losses made the few successful attempts5-8 to experimentally probe non-Hermiticity extremely complicated. We overcome this problem by considering localized plasmonic systems. As the non-Hermiticity in these systems does not stem from temporal invariance breaking but from spatial symmetry breaking, its consequences can be observed more easily. We report on the theoretical and experimental evidence for non-Hermiticity-induced strong coupling between surface plasmon modes of different orders within silver nanodaggers. The symmetry conditions for triggering this counter-intuitive self-hybridization phenomenon are provided. Similar observable effects are expected to exist in any system exhibiting bi-orthogonal eigenmodes.

  9. 2 × 2 random matrix ensembles with reduced symmetry: from Hermitian to PT -symmetric matrices

    International Nuclear Information System (INIS)

    Gong Jiangbin; Wang Qinghai

    2012-01-01

    A possibly fruitful extension of conventional random matrix ensembles is proposed by imposing symmetry constraints on conventional Hermitian matrices or parity–time (PT)-symmetric matrices. To illustrate the main idea, we first study 2 × 2 complex Hermitian matrix ensembles with O(2)-invariant constraints, yielding novel level-spacing statistics such as singular distributions, the half-Gaussian distribution, distributions interpolating between the GOE (Gaussian orthogonal ensemble) distribution and half-Gaussian distributions, as well as the gapped-GOE distribution. Such a symmetry-reduction strategy is then used to explore 2 × 2 PT-symmetric matrix ensembles with real eigenvalues. In particular, PT-symmetric random matrix ensembles with U(2) invariance can be constructed, with the conventional complex Hermitian random matrix ensemble being a special case. In two examples of PT-symmetric random matrix ensembles, the level-spacing distributions are found to be the standard GUE (Gaussian unitary ensemble) statistics or the ‘truncated-GUE’ statistics. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

  10. Hermitian relativity, chromodynamics and confinement

    International Nuclear Information System (INIS)

    Treder, H.J.

    1983-01-01

    The extension of the Riemann metrics of General Relativity to the complex domain (substitution of the symmetry conditions for the fundamental tensor, the affinity and the Ricci curvature by the conditions of hermicity) leads to a 'Generalized Theory of Gravity' (Einstein) describing the Newton-Einstein gravodynamics combined with the chromodynamics of quarks. The interaction of gravodynamics and chromodynamics implied by the Einstein-Schroedinger field equations of the hermitian relativity theory enforces the 'confinement'. The 'confinement' prevents the gravitational potential from divergence which would result in the lack of a Riemann space-time metric

  11. A spin chain model with non-Hermitian interaction: the Ising quantum spin chain in an imaginary field

    International Nuclear Information System (INIS)

    Castro-Alvaredo, Olalla A; Fring, Andreas

    2009-01-01

    We investigate a lattice version of the Yang-Lee model which is characterized by a non-Hermitian quantum spin chain Hamiltonian. We propose a new way to implement PT-symmetry on the lattice, which serves to guarantee the reality of the spectrum in certain regions of values of the coupling constants. In that region of unbroken PT-symmetry, we construct a Dyson map, a metric operator and find the Hermitian counterpart of the Hamiltonian for small values of the number of sites, both exactly and perturbatively. Besides the standard perturbation theory about the Hermitian part of the Hamiltonian, we also carry out an expansion in the second coupling constant of the model. Our constructions turn out to be unique with the sole assumption that the Dyson map is Hermitian. Finally, we analyse the magnetization of the chain in the z- and x-direction.

  12. A Boundary Value Problem for Hermitian Monogenic Functions

    Directory of Open Access Journals (Sweden)

    Ricardo Abreu Blaya

    2008-02-01

    Full Text Available We study the problem of finding a Hermitian monogenic function with a given jump on a given hypersurface in ℝm, m=2n. Necessary and sufficient conditions for the solvability of this problem are obtained.

  13. Optical Lattice Design Assisted by Non-Hermitian Hamiltonians

    International Nuclear Information System (INIS)

    Rodríguez-Lara, B M

    2016-01-01

    A brief introduction to non-Hermitian arrays of coupled waveguides is presented. The PT-symmetric dimer is revisited for the sake of clarity. It belongs to the class of photonic lattices with underlying SO(2,1) symmetry that have been shown to provide all-optical conversion from phase to amplitude. (paper)

  14. Generalized Lie superalgebras and superqravity with a positive cosmological constant

    International Nuclear Information System (INIS)

    Vasil'ev, M.A.

    1984-01-01

    A modified law of Hermitian conjugation has been suggested, which permits to plot the Hermitian effect for supergravitation with a positive cosmological constant Λ. The modified conjugation is shown to result in generalized (Z 2 xZ 2 - graded) Lie superalgebras, corresconding to supergravitation With Λ > 0

  15. Old and New about Positive Definite Matrices

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav

    2015-01-01

    Roč. 484, 1 November (2015), s. 496-503 ISSN 0024-3795 R&D Projects: GA ČR(CZ) GAP108/11/0853 Institutional support: RVO:67985807 Keywords : positive definite matrix * normalized positive definite matrix * sign pattern Subject RIV: BA - General Mathematics Impact factor: 0.965, year: 2015

  16. Geometrical meaning of winding number and its characterization of topological phases in one-dimensional chiral non-Hermitian systems

    Science.gov (United States)

    Yin, Chuanhao; Jiang, Hui; Li, Linhu; Lü, Rong; Chen, Shu

    2018-05-01

    We unveil the geometrical meaning of winding number and utilize it to characterize the topological phases in one-dimensional chiral non-Hermitian systems. While chiral symmetry ensures the winding number of Hermitian systems are integers, it can take half integers for non-Hermitian systems. We give a geometrical interpretation of the half integers by demonstrating that the winding number ν of a non-Hermitian system is equal to half of the summation of two winding numbers ν1 and ν2 associated with two exceptional points, respectively. The winding numbers ν1 and ν2 represent the times of the real part of the Hamiltonian in momentum space encircling the exceptional points and can only take integers. We further find that the difference of ν1 and ν2 is related to the second winding number or energy vorticity. By applying our scheme to a non-Hermitian Su-Schrieffer-Heeger model and an extended version of it, we show that the topologically different phases can be well characterized by winding numbers. Furthermore, we demonstrate that the existence of left and right zero-mode edge states is closely related to the winding number ν1 and ν2.

  17. Generalized Lie superalgebras and a supergravity with a positive cosmological constant

    International Nuclear Information System (INIS)

    Vasil'ev, M.A.

    1984-01-01

    A new law for forming the Hermitian conjugation makes it possible to construct a Hermitian action for a supergravity with a positive cosmological constant Λ. This modified conjugation leads to generalized (Z 2 x Z 2 -gauge) Lie superalgebras that correspond to a supergravity with Λ>0

  18. Comparison of different lattice definitions of the topological charge

    International Nuclear Information System (INIS)

    Cichy, Krzysztof; Ottnad, Konstantin; Bonn Univ.; Bonn Univ.; Urbach, Carsten; Zimmermann, Falk; Bonn Univ.; Wenger, Urs

    2014-11-01

    We present a comparison of different definitions of the topological charge on the lattice, using a small-volume ensemble with 2 flavours of dynamical twisted mass fermions. The investigated definitions are: index of the overlap Dirac operator, spectral projectors, spectral flow of the Hermitian Wilson-Dirac operator and field theoretic with different kinds of smoothing of gauge fields (HYP and APE smearings, gradient flow, cooling). We also show some results on the topological susceptibility.

  19. Random matrix theory for pseudo-Hermitian systems: Cyclic blocks

    Indian Academy of Sciences (India)

    We discuss the relevance of random matrix theory for pseudo-Hermitian systems, and, for Hamiltonians that break parity and time-reversal invariance . In an attempt to understand the random Ising model, we present the treatment of cyclic asymmetric matrices with blocks and show that the nearest-neighbour spacing ...

  20. Non-Hermitian quantum mechanics and localization in physical systems

    International Nuclear Information System (INIS)

    Hatano, Naomichi

    1998-01-01

    Recent studies on a delocalization phenomenon of a non-Hermitian random system is reviewed. The complex spectrum of the system indicates delocalization transition of its eigenfunctions. It is emphasized that the delocalization is related to various physical phenomena such as flux-line pinning in superconductors and population biology of bacteria colony

  1. Non-Hermitian Hamiltonians with a real spectrum and their physical ...

    Indian Academy of Sciences (India)

    We present an evaluation of some recent attempts to understand the role of pseudo-Hermitian and P T -symmetric Hamiltonians in modelling unitary quantum systems and elaborate on a particular physical phenomenon whose discovery originated in the study of complex scattering potentials.

  2. Defect States Emerging from a Non-Hermitian Flatband of Photonic Zero Modes

    Science.gov (United States)

    Qi, Bingkun; Zhang, Lingxuan; Ge, Li

    2018-03-01

    We show the existence of a flatband consisting of photonic zero modes in a gain and loss modulated lattice system as a result of the underlying non-Hermitian particle-hole symmetry. This general finding explains the previous observation in parity-time symmetric systems where non-Hermitian particle-hole symmetry is hidden. We further discuss the defect states in these systems, whose emergence can be viewed as an unconventional alignment of a pseudospin under the influence of a complex-valued pseudomagnetic field. These defect states also behave as a chain with two types of links, one rigid in a unit cell and one soft between unit cells, as the defect states become increasingly localized with the gain and loss strength.

  3. Random matrix theory for pseudo-Hermitian systems: Cyclic blocks

    Indian Academy of Sciences (India)

    Abstract. We discuss the relevance of random matrix theory for pseudo-Hermitian sys- tems, and, for Hamiltonians that break parity P and time-reversal invariance T. In an attempt to understand the random Ising model, we present the treatment of cyclic asym- metric matrices with blocks and show that the nearest-neighbour ...

  4. Extension of the CPT theorem to non-Hermitian Hamiltonians and unstable states

    Energy Technology Data Exchange (ETDEWEB)

    Mannheim, Philip D., E-mail: philip.mannheim@uconn.edu

    2016-02-10

    We extend the CPT theorem to quantum field theories with non-Hermitian Hamiltonians and unstable states. Our derivation is a quite minimal one as it requires only the time-independent evolution of scalar products, invariance under complex Lorentz transformations, and a non-standard but nonetheless perfectly legitimate interpretation of charge conjugation as an antilinear operator. The first of these requirements does not force the Hamiltonian to be Hermitian. Rather, it forces its eigenvalues to either be real or to appear in complex conjugate pairs, forces the eigenvectors of such conjugate pairs to be conjugates of each other, and forces the Hamiltonian to admit of an antilinear symmetry. The latter two requirements then force this antilinear symmetry to be CPT, while forcing the Hamiltonian to be real rather than Hermitian. Our work justifies the use of the CPT theorem in establishing the equality of the lifetimes of unstable particles that are charge conjugates of each other. We show that the Euclidean time path integrals of a CPT-symmetric theory must always be real. In the quantum-mechanical limit the key results of the PT symmetry program of Bender and collaborators are recovered, with the C-operator of the PT symmetry program being identified with the linear component of the charge conjugation operator.

  5. Theory of non-hermitian localization in one dimension: Localization ...

    Indian Academy of Sciences (India)

    of the finite depinning field H . The degree of depinning is measured by the averaged .... system [2] shows a direct relationship between the localization length of the ... tight-binding model in a non-hermitian field h, where the discrete sites n, ..... shows that complex eigenvalues do not appear for field strengths less thanh2.

  6. Hermitian-Einstein metrics on parabolic stable bundles

    International Nuclear Information System (INIS)

    Li Jiayu; Narasimhan, M.S.

    1995-12-01

    Let M-bar be a compact complex manifold of complex dimension two with a smooth Kaehler metric and D a smooth divisor on M-bar. If E is a rank 2 holomorphic vector bundle on M-bar with a stable parabolic structure along D, we prove the existence of a metric on E' = E module MbarD (compatible with the parabolic structure) which is Hermitian-Einstein with respect to the restriction of Kaehler metric of M-barD. A converse is also proved. (author). 24 refs

  7. Data depth and rank-based tests for covariance and spectral density matrices

    KAUST Repository

    Chau, Joris

    2017-06-26

    In multivariate time series analysis, objects of primary interest to study cross-dependences in the time series are the autocovariance or spectral density matrices. Non-degenerate covariance and spectral density matrices are necessarily Hermitian and positive definite, and our primary goal is to develop new methods to analyze samples of such matrices. The main contribution of this paper is the generalization of the concept of statistical data depth for collections of covariance or spectral density matrices by exploiting the geometric properties of the space of Hermitian positive definite matrices as a Riemannian manifold. This allows one to naturally characterize most central or outlying matrices, but also provides a practical framework for rank-based hypothesis testing in the context of samples of covariance or spectral density matrices. First, the desired properties of a data depth function acting on the space of Hermitian positive definite matrices are presented. Second, we propose two computationally efficient pointwise and integrated data depth functions that satisfy each of these requirements. Several applications of the developed methodology are illustrated by the analysis of collections of spectral matrices in multivariate brain signal time series datasets.

  8. Data depth and rank-based tests for covariance and spectral density matrices

    KAUST Repository

    Chau, Joris; Ombao, Hernando; Sachs, Rainer von

    2017-01-01

    In multivariate time series analysis, objects of primary interest to study cross-dependences in the time series are the autocovariance or spectral density matrices. Non-degenerate covariance and spectral density matrices are necessarily Hermitian and positive definite, and our primary goal is to develop new methods to analyze samples of such matrices. The main contribution of this paper is the generalization of the concept of statistical data depth for collections of covariance or spectral density matrices by exploiting the geometric properties of the space of Hermitian positive definite matrices as a Riemannian manifold. This allows one to naturally characterize most central or outlying matrices, but also provides a practical framework for rank-based hypothesis testing in the context of samples of covariance or spectral density matrices. First, the desired properties of a data depth function acting on the space of Hermitian positive definite matrices are presented. Second, we propose two computationally efficient pointwise and integrated data depth functions that satisfy each of these requirements. Several applications of the developed methodology are illustrated by the analysis of collections of spectral matrices in multivariate brain signal time series datasets.

  9. Non-Hermitian systems of Euclidean Lie algebraic type with real energy spectra

    International Nuclear Information System (INIS)

    Dey, Sanjib; Fring, Andreas; Mathanaranjan, Thilagarajah

    2014-01-01

    We study several classes of non-Hermitian Hamiltonian systems, which can be expressed in terms of bilinear combinations of Euclidean–Lie algebraic generators. The classes are distinguished by different versions of antilinear (PT)-symmetries exhibiting various types of qualitative behaviour. On the basis of explicitly computed non-perturbative Dyson maps we construct metric operators, isospectral Hermitian counterparts for which we solve the corresponding time-independent Schrödinger equation for specific choices of the coupling constants. In these cases general analytical expressions for the solutions are obtained in the form of Mathieu functions, which we analyze numerically to obtain the corresponding energy spectra. We identify regions in the parameter space for which the corresponding spectra are entirely real and also domains where the PT symmetry is spontaneously broken and sometimes also regained at exceptional points. In some cases it is shown explicitly how the threshold region from real to complex spectra is characterized by the breakdown of the Dyson maps or the metric operator. We establish the explicit relationship to models currently under investigation in the context of beam dynamics in optical lattices. -- Highlights: •Different PT-symmetries lead to qualitatively different systems. •Construction of non-perturbative Dyson maps and isospectral Hermitian counterparts. •Numerical discussion of the eigenvalue spectra for one of the E(2)-systems. •Established link to systems studied in the context of optical lattices. •Setup for the E(3)-algebra is provided

  10. Computing several eigenpairs of Hermitian problems by conjugate gradient iterations

    International Nuclear Information System (INIS)

    Ovtchinnikov, E.E.

    2008-01-01

    The paper is concerned with algorithms for computing several extreme eigenpairs of Hermitian problems based on the conjugate gradient method. We analyse computational strategies employed by various algorithms of this kind reported in the literature and identify their limitations. Our criticism is illustrated by numerical tests on a set of problems from electronic structure calculations and acoustics

  11. Exact 2-point function in Hermitian matrix model

    International Nuclear Information System (INIS)

    Morozov, A.; Shakirov, Sh.

    2009-01-01

    J. Harer and D. Zagier have found a strikingly simple generating function [1,2] for exact (all-genera) 1-point correlators in the Gaussian Hermitian matrix model. In this paper we generalize their result to 2-point correlators, using Toda integrability of the model. Remarkably, this exact 2-point correlation function turns out to be an elementary function - arctangent. Relation to the standard 2-point resolvents is pointed out. Some attempts of generalization to 3-point and higher functions are described.

  12. Tensor Dictionary Learning for Positive Definite Matrices.

    Science.gov (United States)

    Sivalingam, Ravishankar; Boley, Daniel; Morellas, Vassilios; Papanikolopoulos, Nikolaos

    2015-11-01

    Sparse models have proven to be extremely successful in image processing and computer vision. However, a majority of the effort has been focused on sparse representation of vectors and low-rank models for general matrices. The success of sparse modeling, along with popularity of region covariances, has inspired the development of sparse coding approaches for these positive definite descriptors. While in earlier work, the dictionary was formed from all, or a random subset of, the training signals, it is clearly advantageous to learn a concise dictionary from the entire training set. In this paper, we propose a novel approach for dictionary learning over positive definite matrices. The dictionary is learned by alternating minimization between sparse coding and dictionary update stages, and different atom update methods are described. A discriminative version of the dictionary learning approach is also proposed, which simultaneously learns dictionaries for different classes in classification or clustering. Experimental results demonstrate the advantage of learning dictionaries from data both from reconstruction and classification viewpoints. Finally, a software library is presented comprising C++ binaries for all the positive definite sparse coding and dictionary learning approaches presented here.

  13. Inequalities among partial traces of hermitian operators and partial sums of their eigenvalues

    International Nuclear Information System (INIS)

    Daboul, J.

    1990-01-01

    Two different proofs of the following inequality are given: Tr sup(k)(H):= sup(k)Σ sub(i=1) h sub(i) :sup(k)Σ sub(i=1)(X sub(i), Hx sub(i))≥ sup(k)Σ sub(i=1)E sub(i), for k = 1,-,N, where H is a Hermitian matrix, the {X sub(i), i = 1,2-,k } are any k orthonormal vectors and the e sub(i) are the eigenvalues of H, ordered according to increasing values. This result is a generalization of the well-known fact, that ground state of a Hamiltonian is given by its lowest eigenvalue, E sub(i). It can also be regarded as a generalization, for Hermitian operators, of the invariance of the trace under unitary transformation. A few consequences of the above result are also derived. (author)

  14. Sub-quadratic decoding of one-point hermitian codes

    DEFF Research Database (Denmark)

    Nielsen, Johan Sebastian Rosenkilde; Beelen, Peter

    2015-01-01

    We present the first two sub-quadratic complexity decoding algorithms for one-point Hermitian codes. The first is based on a fast realization of the Guruswami-Sudan algorithm using state-of-the-art algorithms from computer algebra for polynomial-ring matrix minimization. The second is a power...... decoding algorithm: an extension of classical key equation decoding which gives a probabilistic decoding algorithm up to the Sudan radius. We show how the resulting key equations can be solved by the matrix minimization algorithms from computer algebra, yielding similar asymptotic complexities....

  15. Concrete minimal 3 × 3 Hermitian matrices and some general cases

    Directory of Open Access Journals (Sweden)

    Klobouk Abel H.

    2017-12-01

    Full Text Available Given a Hermitian matrix M ∈ M3(ℂ we describe explicitly the real diagonal matrices DM such that ║M + DM║ ≤ ║M + D║ for all real diagonal matrices D ∈ M3(ℂ, where ║ · ║ denotes the operator norm. Moreover, we generalize our techniques to some n × n cases.

  16. Hermitian (ϵ,δ)-Freudenthal-Kantor Triple Systems and Certain Applications of *-Generalized Jordan Triple Systems to Field Theory

    International Nuclear Information System (INIS)

    Kamiya, Noriaki; Sato, Matsuo

    2014-01-01

    We define Hermitian (ϵ,δ)-Freudenthal-Kantor triple systems and prove a structure theorem. We also give some examples of triple systems that are generalizations of the u(N)⊕u(M) and sp(2N)⊕u(1) Hermitian 3-algebras. We apply a *-generalized Jordan triple system to a field theory and obtain a Chern-Simons gauge theory. We find that the novel Higgs mechanism works, where the Chern-Simons gauge theory reduces to a Yang-Mills theory in a certain limit

  17. Duality property for a hermitian scalar field

    International Nuclear Information System (INIS)

    Bisognano, J.J.

    1975-01-01

    A general hermitian scalar Wightman field is considered. On the Hilbert space of physical states ''natural'' domains for certain complex Lorentz transformations are constructed, and a theorem relating these transformations to the TCP symmetry is stated and proved. Under the additional assumption that the field is ''locally'' essentially self-adjoint, duality is considered for the algebras generated by spectral projections of smeared fields. For a class of unbounded regions duality is proved, and for certain bounded regions ''local'' extensions of the algebras are constructed which satisfy duality. The relationship of the arguments presented to the Tomita--Takesaki theory of modular Hilbert algebras is discussed. A separate analysis for the free field is also given. (auth)

  18. A note on Hermitian-Einstein metrics on parabolic stable bundles

    International Nuclear Information System (INIS)

    Li Jiayu; Narasimhan, M.S.

    2000-01-01

    Let M-bar be a compact complex manifold of complex dimension two with a smooth Kaehler metric and D a smooth divisor on M-bar. If E is a rank 2 holomorphic vector bundle on M-bar with a stable parabolic structure along D, we prove that there exists a Hermitian-Einstein metric on E' = E-vertical bar M-barbackslashD compatible with the parabolic structure, and whose curvature is square integrable. (author)

  19. Non-Hermitian systems of Euclidean Lie algebraic type with real energy spectra

    Science.gov (United States)

    Dey, Sanjib; Fring, Andreas; Mathanaranjan, Thilagarajah

    2014-07-01

    We study several classes of non-Hermitian Hamiltonian systems, which can be expressed in terms of bilinear combinations of Euclidean-Lie algebraic generators. The classes are distinguished by different versions of antilinear (PT)-symmetries exhibiting various types of qualitative behaviour. On the basis of explicitly computed non-perturbative Dyson maps we construct metric operators, isospectral Hermitian counterparts for which we solve the corresponding time-independent Schrödinger equation for specific choices of the coupling constants. In these cases general analytical expressions for the solutions are obtained in the form of Mathieu functions, which we analyze numerically to obtain the corresponding energy spectra. We identify regions in the parameter space for which the corresponding spectra are entirely real and also domains where the PT symmetry is spontaneously broken and sometimes also regained at exceptional points. In some cases it is shown explicitly how the threshold region from real to complex spectra is characterized by the breakdown of the Dyson maps or the metric operator. We establish the explicit relationship to models currently under investigation in the context of beam dynamics in optical lattices.

  20. Non-hermitian symmetric N = 2 coset models, Poincare polynomials, and string compactification

    International Nuclear Information System (INIS)

    Fuchs, J.; Schweigert, C.

    1994-01-01

    The field identification problem, including fixed point resolution, is solved for the non-hermitian symmetric N = 2 superconformal coset theories. Thereby these models are finally identified as well-defined modular invariant conformal field theories. As an application, the theories are used as subtheories in N = 2 tensor products with c = 9, which in turn are taken as the inner sector of heterotic superstring compactifications. All string theories of this type are classified, and the chiral ring as well as the number of massless generations and anti-generations are computed with the help of the extended Poincare polynomial. Several equivalences between a priori different non-hermitian coset theories show up; in particular there is a level-rank duality for an infinite series of coset theories based on C-type Lie algebras. Further, some general results for generic N = 2 coset theories are proven: a simple formula for the number of identification currents is found, and it is shown that the set of Ramond ground states of any N = 2 coset model is invariant under charge conjugation. (orig.)

  1. Information Geometry of Positive Measures and Positive-Definite Matrices: Decomposable Dually Flat Structure

    Directory of Open Access Journals (Sweden)

    Shun-ichi Amari

    2014-04-01

    Full Text Available Information geometry studies the dually flat structure of a manifold, highlighted by the generalized Pythagorean theorem. The present paper studies a class of Bregman divergences called the (ρ,τ-divergence. A (ρ,τ -divergence generates a dually flat structure in the manifold of positive measures, as well as in the manifold of positive-definite matrices. The class is composed of decomposable divergences, which are written as a sum of componentwise divergences. Conversely, a decomposable dually flat divergence is shown to be a (ρ,τ -divergence. A (ρ,τ -divergence is determined from two monotone scalar functions, ρ and τ. The class includes the KL-divergence, α-, β- and (α, β-divergences as special cases. The transformation between an affine parameter and its dual is easily calculated in the case of a decomposable divergence. Therefore, such a divergence is useful for obtaining the center for a cluster of points, which will be applied to classification and information retrieval in vision. For the manifold of positive-definite matrices, in addition to the dually flatness and decomposability, we require the invariance under linear transformations, in particular under orthogonal transformations. This opens a way to define a new class of divergences, called the (ρ,τ -structure in the manifold of positive-definite matrices.

  2. Some thoughts on positive definiteness in the consideration of nuclear data covariance matrices

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, L.P.; Smith, D.L.

    1988-01-01

    Some basic mathematical features of covariance matrices are reviewed, particularly as they relate to the property of positive difiniteness. Physical implications of positive definiteness are also discussed. Consideration is given to an examination of the origins of non-positive definite matrices, to procedures which encourage the generation of positive definite matrices and to the testing of covariance matrices for positive definiteness. Attention is also given to certain problems associated with the construction of covariance matrices using information which is obtained from evaluated data files recorded in the ENDF format. Examples are provided to illustrate key points pertaining to each of the topic areas covered.

  3. Some thoughts on positive definiteness in the consideration of nuclear data covariance matrices

    International Nuclear Information System (INIS)

    Geraldo, L.P.; Smith, D.L.

    1988-01-01

    Some basic mathematical features of covariance matrices are reviewed, particularly as they relate to the property of positive difiniteness. Physical implications of positive definiteness are also discussed. Consideration is given to an examination of the origins of non-positive definite matrices, to procedures which encourage the generation of positive definite matrices and to the testing of covariance matrices for positive definiteness. Attention is also given to certain problems associated with the construction of covariance matrices using information which is obtained from evaluated data files recorded in the ENDF format. Examples are provided to illustrate key points pertaining to each of the topic areas covered

  4. Chequered surfaces and complex matrices

    International Nuclear Information System (INIS)

    Morris, T.R.; Southampton Univ.

    1991-01-01

    We investigate a large-N matrix model involving general complex matrices. It can be reinterpreted as a model of two hermitian matrices with specific couplings, and as a model of positive definite hermitian matrices. Large-N perturbation theory generates dynamical triangulations in which the triangles can be chequered (i.e. coloured so that neighbours are opposite colours). On a sphere there is a simple relation between such triangulations and those generated by the single hermitian matrix model. For the torus (and a quartic potential) we solve the counting problem for the number of triangulations that cannot be quechered. The critical physics of chequered triangulations is the same as that of the hermitian matrix model. We show this explicitly by solving non-perturbatively pure two-dimensional ''chequered'' gravity. The interpretative framework given here applies to a number of other generalisations of the hermitian matrix model. (orig.)

  5. An integral conservative gridding--algorithm using Hermitian curve interpolation.

    Science.gov (United States)

    Volken, Werner; Frei, Daniel; Manser, Peter; Mini, Roberto; Born, Ernst J; Fix, Michael K

    2008-11-07

    The problem of re-sampling spatially distributed data organized into regular or irregular grids to finer or coarser resolution is a common task in data processing. This procedure is known as 'gridding' or 're-binning'. Depending on the quantity the data represents, the gridding-algorithm has to meet different requirements. For example, histogrammed physical quantities such as mass or energy have to be re-binned in order to conserve the overall integral. Moreover, if the quantity is positive definite, negative sampling values should be avoided. The gridding process requires a re-distribution of the original data set to a user-requested grid according to a distribution function. The distribution function can be determined on the basis of the given data by interpolation methods. In general, accurate interpolation with respect to multiple boundary conditions of heavily fluctuating data requires polynomial interpolation functions of second or even higher order. However, this may result in unrealistic deviations (overshoots or undershoots) of the interpolation function from the data. Accordingly, the re-sampled data may overestimate or underestimate the given data by a significant amount. The gridding-algorithm presented in this work was developed in order to overcome these problems. Instead of a straightforward interpolation of the given data using high-order polynomials, a parametrized Hermitian interpolation curve was used to approximate the integrated data set. A single parameter is determined by which the user can control the behavior of the interpolation function, i.e. the amount of overshoot and undershoot. Furthermore, it is shown how the algorithm can be extended to multidimensional grids. The algorithm was compared to commonly used gridding-algorithms using linear and cubic interpolation functions. It is shown that such interpolation functions may overestimate or underestimate the source data by about 10-20%, while the new algorithm can be tuned to

  6. An integral conservative gridding-algorithm using Hermitian curve interpolation

    International Nuclear Information System (INIS)

    Volken, Werner; Frei, Daniel; Manser, Peter; Mini, Roberto; Born, Ernst J; Fix, Michael K

    2008-01-01

    The problem of re-sampling spatially distributed data organized into regular or irregular grids to finer or coarser resolution is a common task in data processing. This procedure is known as 'gridding' or 're-binning'. Depending on the quantity the data represents, the gridding-algorithm has to meet different requirements. For example, histogrammed physical quantities such as mass or energy have to be re-binned in order to conserve the overall integral. Moreover, if the quantity is positive definite, negative sampling values should be avoided. The gridding process requires a re-distribution of the original data set to a user-requested grid according to a distribution function. The distribution function can be determined on the basis of the given data by interpolation methods. In general, accurate interpolation with respect to multiple boundary conditions of heavily fluctuating data requires polynomial interpolation functions of second or even higher order. However, this may result in unrealistic deviations (overshoots or undershoots) of the interpolation function from the data. Accordingly, the re-sampled data may overestimate or underestimate the given data by a significant amount. The gridding-algorithm presented in this work was developed in order to overcome these problems. Instead of a straightforward interpolation of the given data using high-order polynomials, a parametrized Hermitian interpolation curve was used to approximate the integrated data set. A single parameter is determined by which the user can control the behavior of the interpolation function, i.e. the amount of overshoot and undershoot. Furthermore, it is shown how the algorithm can be extended to multidimensional grids. The algorithm was compared to commonly used gridding-algorithms using linear and cubic interpolation functions. It is shown that such interpolation functions may overestimate or underestimate the source data by about 10-20%, while the new algorithm can be tuned to

  7. Photonic Band Structure of Dispersive Metamaterials Formulated as a Hermitian Eigenvalue Problem

    KAUST Repository

    Raman, Aaswath

    2010-02-26

    We formulate the photonic band structure calculation of any lossless dispersive photonic crystal and optical metamaterial as a Hermitian eigenvalue problem. We further show that the eigenmodes of such lossless systems provide an orthonormal basis, which can be used to rigorously describe the behavior of lossy dispersive systems in general. © 2010 The American Physical Society.

  8. Photonic Band Structure of Dispersive Metamaterials Formulated as a Hermitian Eigenvalue Problem

    KAUST Repository

    Raman, Aaswath; Fan, Shanhui

    2010-01-01

    We formulate the photonic band structure calculation of any lossless dispersive photonic crystal and optical metamaterial as a Hermitian eigenvalue problem. We further show that the eigenmodes of such lossless systems provide an orthonormal basis, which can be used to rigorously describe the behavior of lossy dispersive systems in general. © 2010 The American Physical Society.

  9. Correlation functions for Hermitian many-body systems: Necessary conditions

    International Nuclear Information System (INIS)

    Brown, E.B.

    1994-01-01

    Lee [Phys. Rev. B 47, 8293 (1993)] has shown that the odd-numbered derivatives of the Kubo autocorrelation function vanish at t=0. We show that this condition is based on a more general property of nondiagonal Kubo correlation functions. This general property provides that certain functional forms (e.g., simple exponential decay) are not admissible for any symmetric or antisymmetric Kubo correlation function in a Hermitian many-body system. Lee's result emerges as a special case of this result. Applications to translationally invariant systems and systems with rotational symmetries are also demonstrated

  10. Superradiance, disorder, and the non-Hermitian Hamiltonian in open quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Celardo, G. L.; Biella, A.; Giusteri, G. G.; Mattiotti, F. [Dipartimento di Matematica e Fisica and Interdisciplinary Laboratories for Advanced Materials Physics, Università Cattolica, via Musei 41, 25121 Brescia (Italy); Zhang, Y.; Kaplan, L. [Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118 (United States)

    2014-10-15

    We first briefly review the non-Hermitian effective Hamiltonian approach to open quantum systems and the associated phenomenon of superradiance. We next discuss the superradiance crossover in the presence of disorder and the relationship between superradiance and the localization transition. Finally, we investigate the regime of validity of the energy-independent effective Hamiltonian approximation and show that the results obtained by these methods are applicable to realistic physical systems.

  11. Generalized Eigenvalues for pairs on heritian matrices

    Science.gov (United States)

    Rublein, George

    1988-01-01

    A study was made of certain special cases of a generalized eigenvalue problem. Let A and B be nxn matrics. One may construct a certain polynomial, P(A,B, lambda) which specializes to the characteristic polynomial of B when A equals I. In particular, when B is hermitian, that characteristic polynomial, P(I,B, lambda) has real roots, and one can ask: are the roots of P(A,B, lambda) real when B is hermitian. We consider the case where A is positive definite and show that when N equals 3, the roots are indeed real. The basic tools needed in the proof are Shur's theorem on majorization for eigenvalues of hermitian matrices and the interlacing theorem for the eigenvalues of a positive definite hermitian matrix and one of its principal (n-1)x(n-1) minors. The method of proof first reduces the general problem to one where the diagonal of B has a certain structure: either diag (B) = diag (1,1,1) or diag (1,1,-1), or else the 2 x 2 principal minors of B are all 1. According as B has one of these three structures, we use an appropriate method to replace A by a positive diagonal matrix. Since it can be easily verified that P(D,B, lambda) has real roots, the result follows. For other configurations of B, a scaling and a continuity argument are used to prove the result in general.

  12. Large-N limit of the two-Hermitian-matrix model by the hidden BRST method

    International Nuclear Information System (INIS)

    Alfaro, J.

    1993-01-01

    This paper discusses the large-N limit of the two-Hermitian-matrix model in zero dimensions, using the hidden Becchi-Rouet-Stora-Tyutin method. A system of integral equations previously found is solved, showing that it contained the exact solution of the model in leading order of large N

  13. Complexified coherent states and quantum evolution with non-Hermitian Hamiltonians

    International Nuclear Information System (INIS)

    Graefe, Eva-Maria; Schubert, Roman

    2012-01-01

    The complex geometry underlying the Schrödinger dynamics of coherent states for non-Hermitian Hamiltonians is investigated. In particular, two seemingly contradictory approaches are compared: (i) a complex WKB formalism, for which the centres of coherent states naturally evolve along complex trajectories, which leads to a class of complexified coherent states; (ii) the investigation of the dynamical equations for the real expectation values of position and momentum, for which an Ehrenfest theorem has been derived in a previous paper, yielding real but non-Hamiltonian classical dynamics on phase space for the real centres of coherent states. Both approaches become exact for quadratic Hamiltonians. The apparent contradiction is resolved building on an observation by Huber, Heller and Littlejohn, that complexified coherent states are equivalent if their centres lie on a specific complex Lagrangian manifold. A rich underlying complex symplectic geometry is unravelled. In particular, a natural complex structure is identified that defines a projection from complex to real phase space, mapping complexified coherent states to their real equivalents. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)

  14. Eigenvalues of Words in Two Positive Definite Letters

    OpenAIRE

    Hillar, Christopher J; Johnson, Charles R

    2005-01-01

    The question of whether all words in two real positive definite letters have only positive eigenvalues is addressed and settled (negatively). This question was raised some time ago in connection with a long-standing problem in theoretical physics. A large class of words that do guarantee positive eigenvalues is identified, and considerable evidence is given for the conjecture that no other words do. In the process, a fundamental question about solvability of symmetric word equations is encoun...

  15. Multivariable Christoffel-Darboux Kernels and Characteristic Polynomials of Random Hermitian Matrices

    Directory of Open Access Journals (Sweden)

    Hjalmar Rosengren

    2006-12-01

    Full Text Available We study multivariable Christoffel-Darboux kernels, which may be viewed as reproducing kernels for antisymmetric orthogonal polynomials, and also as correlation functions for products of characteristic polynomials of random Hermitian matrices. Using their interpretation as reproducing kernels, we obtain simple proofs of Pfaffian and determinant formulas, as well as Schur polynomial expansions, for such kernels. In subsequent work, these results are applied in combinatorics (enumeration of marked shifted tableaux and number theory (representation of integers as sums of squares.

  16. Digital coherent superposition of optical OFDM subcarrier pairs with Hermitian symmetry for phase noise mitigation.

    Science.gov (United States)

    Yi, Xingwen; Chen, Xuemei; Sharma, Dinesh; Li, Chao; Luo, Ming; Yang, Qi; Li, Zhaohui; Qiu, Kun

    2014-06-02

    Digital coherent superposition (DCS) provides an approach to combat fiber nonlinearities by trading off the spectrum efficiency. In analogy, we extend the concept of DCS to the optical OFDM subcarrier pairs with Hermitian symmetry to combat the linear and nonlinear phase noise. At the transmitter, we simply use a real-valued OFDM signal to drive a Mach-Zehnder (MZ) intensity modulator biased at the null point and the so-generated OFDM signal is Hermitian in the frequency domain. At receiver, after the conventional OFDM signal processing, we conduct DCS of the optical OFDM subcarrier pairs, which requires only conjugation and summation. We show that the inter-carrier-interference (ICI) due to phase noise can be reduced because of the Hermitain symmetry. In a simulation, this method improves the tolerance to the laser phase noise. In a nonlinear WDM transmission experiment, this method also achieves better performance under the influence of cross phase modulation (XPM).

  17. Interpolation between Airy and Poisson statistics for unitary chiral non-Hermitian random matrix ensembles

    International Nuclear Information System (INIS)

    Akemann, G.; Bender, M.

    2010-01-01

    We consider a family of chiral non-Hermitian Gaussian random matrices in the unitarily invariant symmetry class. The eigenvalue distribution in this model is expressed in terms of Laguerre polynomials in the complex plane. These are orthogonal with respect to a non-Gaussian weight including a modified Bessel function of the second kind, and we give an elementary proof for this. In the large n limit, the eigenvalue statistics at the spectral edge close to the real axis are described by the same family of kernels interpolating between Airy and Poisson that was recently found by one of the authors for the elliptic Ginibre ensemble. We conclude that this scaling limit is universal, appearing for two different non-Hermitian random matrix ensembles with unitary symmetry. As a second result we give an equivalent form for the interpolating Airy kernel in terms of a single real integral, similar to representations for the asymptotic kernel in the bulk and at the hard edge of the spectrum. This makes its structure as a one-parameter deformation of the Airy kernel more transparent.

  18. Snyder noncommutativity and pseudo-Hermitian Hamiltonians from a Jordanian twist

    International Nuclear Information System (INIS)

    Castro, P.G.; Kullock, R.; Toppan, F.

    2011-01-01

    Nonrelativistic quantum mechanics and conformal quantum mechanics are de- formed through a Jordanian twist. The deformed space coordinates satisfy the Snyder noncommutativity. The resulting deformed Hamiltonians are pseudo-Hermitian Hamiltonians of the type discussed by Mostafazadeh. The quantization scheme makes use of the so-called 'unfolded formalism' discussed in previous works. A Hopf algebra structure, compatible with the physical interpretation of the coproduct, is introduced for the Universal Enveloping Algebra of a suitably chosen dynamical Lie algebra (the Hamiltonian is contained among its generators). The multi-particle sector, uniquely determined by the deformed 2-particle Hamiltonian, is composed of bosonic particles. (author)

  19. 20th International Workshop on Hermitian Symmetric Spaces and Submanifolds

    CERN Document Server

    Ohnita, Yoshihiro; Zhou, Jiazu; Kim, Byung; Lee, Hyunjin

    2017-01-01

    This book presents the proceedings of the 20th International Workshop on Hermitian Symmetric Spaces and Submanifolds, which was held at the Kyungpook National University from June 21 to 25, 2016. The Workshop was supported by the Research Institute of Real and Complex Manifolds (RIRCM) and the National Research Foundation of Korea (NRF). The Organizing Committee invited 30 active geometers of differential geometry and related fields from all around the globe to discuss new developments for research in the area. These proceedings provide a detailed overview of recent topics in the field of real and complex submanifolds.

  20. Strings from position-dependent noncommutativity

    International Nuclear Information System (INIS)

    Fring, Andreas; Gouba, Laure; Scholtz, Frederik G

    2010-01-01

    We introduce a new set of noncommutative spacetime commutation relations in two space dimensions. The space-space commutation relations are deformations of the standard flat noncommutative spacetime relations taken here to have position-dependent structure constants. Some of the new variables are non-Hermitian in the most natural choice. We construct their Hermitian counterparts by means of a Dyson map, which also serves to introduce a new metric operator. We propose PT-like symmetries, i.e. antilinear involutory maps, respected by these deformations. We compute minimal lengths and momenta arising in this space from generalized versions of Heisenberg's uncertainty relations and find that any object in this two-dimensional space is string like, i.e. having a fundamental length in one direction beyond which a resolution is impossible. Subsequently, we formulate and partly solve some simple models in these new variables, the free particle, its PT-symmetric deformations and the harmonic oscillator.

  1. Coping, goal adjustment, and positive and negative affect in definitive infertility

    NARCIS (Netherlands)

    Kraaij, V.; Garnefski, N.; Schroevers, M.J.

    2009-01-01

    The relationships between coping strategies, goal adjustment and positive and negative affect were studied in 83 definitive involuntary childless people. Self-report questionnaires were filled out. The findings suggested that positive ways to handle the childlessness were related to positive affect,

  2. Non-Hermitian Operator Modelling of Basic Cancer Cell Dynamics

    Science.gov (United States)

    Bagarello, Fabio; Gargano, Francesco

    2018-04-01

    We propose a dynamical system of tumor cells proliferation based on operatorial methods. The approach we propose is quantum-like: we use ladder and number operators to describe healthy and tumor cells birth and death, and the evolution is ruled by a non-hermitian Hamiltonian which includes, in a non reversible way, the basic biological mechanisms we consider for the system. We show that this approach is rather efficient in describing some processes of the cells. We further add some medical treatment, described by adding a suitable term in the Hamiltonian, which controls and limits the growth of tumor cells, and we propose an optimal approach to stop, and reverse, this growth.

  3. Non-Hermitian interaction representation and its use in relativistic quantum mechanics

    Czech Academy of Sciences Publication Activity Database

    Znojil, Miloslav

    2017-01-01

    Roč. 385, č. 10 (2017), s. 162-179 ISSN 0003-4916 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : unitary quantum systems * non-Hermitian version of Dirac's interaction picture * complete set of time-evolution equations * application in relativistic quantum mechanics * Klein-Gordon example with space-time-dependent mass Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics ( physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.465, year: 2016

  4. Investigating the Composite Step Biconjugate A-Orthogonal Residual Method for Non-Hermitian Dense Linear Systems in Electromagnetics

    NARCIS (Netherlands)

    Jing, Yan-Fei; Huang, Ting-Zhu; Carpentieri, Bruno; Duan, Yong

    An interesting stabilizing variant of the biconjugate A-orthogonal residual (BiCOR) method is investigated for solving dense complex non-Hermitian systems of linear equations arising from the Galerlcin discretization of surface integral equations in electromagnetics. The novel variant is naturally

  5. Phase integral approximation for coupled ordinary differential equations of the Schroedinger type

    International Nuclear Information System (INIS)

    Skorupski, Andrzej A.

    2008-01-01

    Four generalizations of the phase integral approximation (PIA) to sets of ordinary differential equations of Schroedinger type [u j '' (x)+Σ k=1 N R jk (x)u k (x)=0, j=1,2,...,N] are described. The recurrence relations for higher order corrections are given in a form valid to arbitrary order and for the matrix R(x)[≡(R jk (x))] either Hermitian or non-Hermitian. For Hermitian and negative definite R(x) matrices, a Wronskian conserving PIA theory is formulated, which generalizes Fulling's current conserving theory pertinent to positive definite R(x) matrices. The idea of a modification of the PIA, which is well known for one equation [u '' (x)+R(x)u(x)=0], is generalized to sets. A simplification of Wronskian or current conserving theories is proposed which in each order eliminates one integration from the formulas for higher order corrections. If the PIA is generated by a nondegenerate eigenvalue of the R(x) matrix, the eliminated integration is the only one present. In that case, the simplified theory becomes fully algorithmic and is generalized to non-Hermitian R(x) matrices. The general theory is illustrated by a few examples automatically generated by using the author's program in MATHEMATICA published in e-print arXiv:0710.5406 [math-ph

  6. Snyder noncommutativity and pseudo-Hermitian Hamiltonians from a Jordanian twist

    Energy Technology Data Exchange (ETDEWEB)

    Castro, P.G., E-mail: pgcastro@cbpf.b [Universidade Federal de Juiz de Fora (DM/ICE/UFJF), Juiz de Fora, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Matematica; Kullock, R.; Toppan, F., E-mail: ricardokl@cbpf.b, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (TEO/CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Fisica Teorica

    2011-07-01

    Nonrelativistic quantum mechanics and conformal quantum mechanics are de- formed through a Jordanian twist. The deformed space coordinates satisfy the Snyder noncommutativity. The resulting deformed Hamiltonians are pseudo-Hermitian Hamiltonians of the type discussed by Mostafazadeh. The quantization scheme makes use of the so-called 'unfolded formalism' discussed in previous works. A Hopf algebra structure, compatible with the physical interpretation of the coproduct, is introduced for the Universal Enveloping Algebra of a suitably chosen dynamical Lie algebra (the Hamiltonian is contained among its generators). The multi-particle sector, uniquely determined by the deformed 2-particle Hamiltonian, is composed of bosonic particles. (author)

  7. Problem of the coexistence of several non-Hermitian observables in PT -symmetric quantum mechanics

    Czech Academy of Sciences Publication Activity Database

    Znojil, Miloslav; Semorádová, Iveta; Růžička, František; Moulla, H.; Leghrib, I.

    2017-01-01

    Roč. 95, č. 4 (2017), č. článku 042122. ISSN 2469-9926 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : operators * Hilbert space * non-Hermitian Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.925, year: 2016

  8. Jacobi-Davidson methods for generalized MHD-eigenvalue problems

    NARCIS (Netherlands)

    J.G.L. Booten; D.R. Fokkema; G.L.G. Sleijpen; H.A. van der Vorst (Henk)

    1995-01-01

    textabstractA Jacobi-Davidson algorithm for computing selected eigenvalues and associated eigenvectors of the generalized eigenvalue problem $Ax = lambda Bx$ is presented. In this paper the emphasis is put on the case where one of the matrices, say the B-matrix, is Hermitian positive definite. The

  9. Frobenius–Perron eigenstates in deformed microdisk cavities: non-Hermitian physics and asymmetric backscattering in ray dynamics

    International Nuclear Information System (INIS)

    Kullig, Julius; Wiersig, Jan

    2016-01-01

    In optical microdisk cavities with boundary deformations the backscattering between clockwise and counter-clockwise propagating waves is in general asymmetric. The striking consequence of this asymmetry is that these apparently weakly open systems show pronounced non-Hermitian phenomena. The optical modes appear in non-orthogonal pairs, where both modes copropagate in a preferred sense of rotation, i.e. the modes exhibit a finite chirality. Full asymmetry in the backscattering results in a non-Hermitian degeneracy (exceptional point) where the deviation from closed system evolution is strongest. We study the effects of asymmetric backscattering in ray dynamics. For this purpose, we construct a finite approximation of the Frobenius–Perron operator for deformed microdisk cavities, which describes the dynamics of intensities in phase space. Eigenstates of the Frobenius–Perron operator show nice analogies to optical modes: they come in non-orthogonal copropagating pairs and have a finite chirality. We introduce a new cavity system with a smooth asymmetric boundary deformation where we demonstrate our results and we illustrate the main aspects with the help of a simple analytically solvable 1D model. (paper)

  10. Projective block Lanczos algorithm for dense, Hermitian eigensystems

    International Nuclear Information System (INIS)

    Webster, F.; Lo, G.C.

    1996-01-01

    Projection operators are used to effect open-quotes deflation by restrictionclose quotes and it is argued that this is an optimal Lanczos algorithm for memory minimization. Algorithmic optimization is constrained to dense, Hermitian eigensystems where a significant number of the extreme eigenvectors must be obtained reliably and completely. The defining constraints are operator algebra without a matrix representation and semi-orthogonalization without storage of Krylov vectors. other semi-orthogonalization strategies for Lanczos algorithms and conjugate gradient techniques are evaluated within these constraints. Large scale, sparse, complex numerical experiments are performed on clusters of magnetic dipoles, a quantum many-body system that is not block-diagonalizable. Plane-wave, density functional theory of beryllium clusters provides examples of dense complex eigensystems. Use of preconditioners and spectral transformations is evaluated in a preprocessor prior to a high accuracy self-consistent field calculation. 25 refs., 3 figs., 5 tabs

  11. On Some Analytic Operator Functions in the Theory of Hermitian Operators

    Directory of Open Access Journals (Sweden)

    Perch Melik-Adamyan

    2014-01-01

    Full Text Available A densely defined Hermitian operator $A_0$ with equal defect numbers is considered. Presentable by means of resolvents of a certain maximal dissipative or accumulative extensions of $A_0$, bounded linear operators acting from some defect subspace $\\mfn_\\gamma$ to arbitrary other $\\mfn_\\lambda$ are investigated. With their aid are discussed characteristic and Weyl functions. A family of Weyl functions is described, associated with a given self-adjoint extension of $A_0$. The specific property of Weyl function's factors enabled to obtain a modified formulas of von Neumann. In terms of characteristic and Weyl functions of suitably chosen extensions the resolvent of Weyl function is presented explicitly.

  12. Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting.

    Science.gov (United States)

    Kim, Soo Jin; Kang, Ju-Hyung; Mutlu, Mehmet; Park, Joonsuk; Park, Woosung; Goodson, Kenneth E; Sinclair, Robert; Fan, Shanhui; Kik, Pieter G; Brongersma, Mark L

    2018-01-22

    The ability to split an incident light beam into separate wavelength bands is central to a diverse set of optical applications, including imaging, biosensing, communication, photocatalysis, and photovoltaics. Entirely new opportunities are currently emerging with the recently demonstrated possibility to spectrally split light at a subwavelength scale with optical antennas. Unfortunately, such small structures offer limited spectral control and are hard to exploit in optoelectronic devices. Here, we overcome both challenges and demonstrate how within a single-layer metafilm one can laterally sort photons of different wavelengths below the free-space diffraction limit and extract a useful photocurrent. This chipscale demonstration of anti-Hermitian coupling between resonant photodetector elements also facilitates near-unity photon-sorting efficiencies, near-unity absorption, and a narrow spectral response (∼ 30 nm) for the different wavelength channels. This work opens up entirely new design paradigms for image sensors and energy harvesting systems in which the active elements both sort and detect photons.

  13. The Optimization on Ranks and Inertias of a Quadratic Hermitian Matrix Function and Its Applications

    Directory of Open Access Journals (Sweden)

    Yirong Yao

    2013-01-01

    Full Text Available We solve optimization problems on the ranks and inertias of the quadratic Hermitian matrix function subject to a consistent system of matrix equations and . As applications, we derive necessary and sufficient conditions for the solvability to the systems of matrix equations and matrix inequalities , and in the Löwner partial ordering to be feasible, respectively. The findings of this paper widely extend the known results in the literature.

  14. Positive definite functions and dual pairs of locally convex spaces

    Directory of Open Access Journals (Sweden)

    Daniel Alpay

    2018-01-01

    Full Text Available Using pairs of locally convex topological vector spaces in duality and topologies defined by directed families of sets bounded with respect to the duality, we prove general factorization theorems and general dilation theorems for operator-valued positive definite functions.

  15. A Robust Incomplete Factorization Preconditioner for Positive Definite Matrices

    Czech Academy of Sciences Publication Activity Database

    Benzi, M.; Tůma, Miroslav

    2003-01-01

    Roč. 10, - (2003), s. 385-400 ISSN 1070-5325 R&D Projects: GA AV ČR IAA2030801; GA AV ČR IAA1030103 Institutional research plan: AV0Z1030915 Keywords : sparse linear systems * positive definite matrices * preconditioned conjugate gradient s * incomplete factorization * A-orthogonalization * SAINV Subject RIV: BA - General Mathematics Impact factor: 1.042, year: 2003

  16. A method to compute the inverse of a complex n-block tridiagonal quasi-hermitian matrix

    International Nuclear Information System (INIS)

    Godfrin, Elena

    1990-01-01

    This paper presents a method to compute the inverse of a complex n-block tridiagonal quasi-hermitian matrix using adequate partitions of the complete matrix. This type of matrix is very usual in quantum mechanics and, more specifically, in solid state physics (e.g., interfaces and superlattices), when the tight-binding approximation is used. The efficiency of the method is analyzed comparing the required CPU time and work-area for different usual techniques. (Author)

  17. Robust domain decomposition preconditioners for abstract symmetric positive definite bilinear forms

    KAUST Repository

    Efendiev, Yalchin; Galvis, Juan; Lazarov, Raytcho; Willems, Joerg

    2012-01-01

    An abstract framework for constructing stable decompositions of the spaces corresponding to general symmetric positive definite problems into "local" subspaces and a global "coarse" space is developed. Particular applications of this abstract

  18. E2-quasi-exact solvability for non-Hermitian models

    International Nuclear Information System (INIS)

    Fring, Andreas

    2015-01-01

    We propose the notion of E 2 -quasi-exact solvability and apply this idea to find explicit solutions to the eigenvalue problem for a non-Hermitian Hamiltonian system depending on two parameters. The model considered reduces to the complex Mathieu Hamiltonian in a double scaling limit, which enables us to compute the exceptional points in the energy spectrum of the latter as a limiting process of the zeros for some algebraic equations. The coefficient functions in the quasi-exact eigenfunctions are univariate polynomials in the energy obeying a three-term recurrence relation. The latter property guarantees the existence of a linear functional such that the polynomials become orthogonal. The polynomials are shown to factorize for all levels above the quantization condition leading to vanishing norms rendering them to be weakly orthogonal. In two concrete examples we compute the explicit expressions for the Stieltjes measure. (paper)

  19. E2-quasi-exact solvability for non-Hermitian models

    Science.gov (United States)

    Fring, Andreas

    2015-04-01

    We propose the notion of E2-quasi-exact solvability and apply this idea to find explicit solutions to the eigenvalue problem for a non-Hermitian Hamiltonian system depending on two parameters. The model considered reduces to the complex Mathieu Hamiltonian in a double scaling limit, which enables us to compute the exceptional points in the energy spectrum of the latter as a limiting process of the zeros for some algebraic equations. The coefficient functions in the quasi-exact eigenfunctions are univariate polynomials in the energy obeying a three-term recurrence relation. The latter property guarantees the existence of a linear functional such that the polynomials become orthogonal. The polynomials are shown to factorize for all levels above the quantization condition leading to vanishing norms rendering them to be weakly orthogonal. In two concrete examples we compute the explicit expressions for the Stieltjes measure.

  20. Evaluating functions of positive-definite matrices using colored-noise thermostats

    Science.gov (United States)

    Nava, Marco; Ceriotti, Michele; Dryzun, Chaim; Parrinello, Michele

    2014-02-01

    Many applications in computational science require computing the elements of a function of a large matrix. A commonly used approach is based on the the evaluation of the eigenvalue decomposition, a task that, in general, involves a computing time that scales with the cube of the size of the matrix. We present here a method that can be used to evaluate the elements of a function of a positive-definite matrix with a scaling that is linear for sparse matrices and quadratic in the general case. This methodology is based on the properties of the dynamics of a multidimensional harmonic potential coupled with colored-noise, generalized Langevin equation thermostats. This "f-thermostat" approach allows us to calculate directly elements of functions of a positive-definite matrix by carefully tailoring the properties of the stochastic dynamics. We demonstrate the scaling and the accuracy of this approach for both dense and sparse problems and compare the results with other established methodologies.

  1. Wigner-Smith delay times and the non-Hermitian Hamiltonian for the HOCl molecule

    International Nuclear Information System (INIS)

    Barr, A.M.; Reichl, L.E.

    2013-01-01

    We construct the scattering matrix for a two-dimensional model of a Cl atom scattering from an OH dimer. We show that the scattering matrix can be written in terms of a non-Hermitian Hamiltonian whose complex energy eigenvalues can be used to compute Wigner-Smith delay times for the Cl-OH scattering process. We compute the delay times for a range of energies, and show that the scattering states with the longest delay times are strongly influenced by unstable periodic orbits in the classical dynamics. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. On the remarkable spectrum of a non-Hermitian random matrix model

    International Nuclear Information System (INIS)

    Holz, D E; Orland, H; Zee, A

    2003-01-01

    A non-Hermitian random matrix model proposed a few years ago has a remarkably intricate spectrum. Various attempts have been made to understand the spectrum, but even its dimension is not known. Using the Dyson-Schmidt equation, we show that the spectrum consists of a non-denumerable set of lines in the complex plane. Each line is the support of the spectrum of a periodic Hamiltonian, obtained by the infinite repetition of any finite sequence of the disorder variables. Our approach is based on the 'theory of words'. We make a complete study of all four-letter words. The spectrum is complicated because our matrix contains everything that will ever be written in the history of the universe, including this particular paper

  3. Gyroscopic stabilization and indefimite damped systems

    DEFF Research Database (Denmark)

    Pommer, Christian

    a class of feasibel skew-Hermitian matrices A depending on the choise of M. The theory can be applied to dynamical systems of the form x''(t) + ( dD + g G) x'(t) + K x(t) = 0 where G is a skew symmetric gyrocopic matrix, D is a symmetric indefinite damping matrix and K > 0 is a positive definite stiffness......An important issue is how to modify a given unstable matrix in such a way that the resulting matrix is stable. We investigate in general under which condition a matrix M+A is stable,where M is an arbitrary matrix and A is skew-Hermitian. We show that if trace(M) > 0 it is always possible to find...

  4. Robust Solvers for Symmetric Positive Definite Operators and Weighted Poincaré Inequalities

    KAUST Repository

    Efendiev, Yalchin; Galvis, Juan; Lazarov, Raytcho; Willems, Joerg

    2012-01-01

    An abstract setting for robustly preconditioning symmetric positive definite (SPD) operators is presented. The term "robust" refers to the property of the condition numbers of the preconditioned systems being independent of mesh parameters

  5. Multiphoton ionization of H+2 at critical internuclear separations: non-Hermitian Floquet analysis

    International Nuclear Information System (INIS)

    Likhatov, P V; Telnov, D A

    2009-01-01

    We present ab initio time-dependent non-Hermitian Floquet calculations of multiphoton ionization (MPI) rates of hydrogen molecular ions subject to an intense linearly polarized monochromatic laser field with a wavelength of 800 nm. The orientation of the molecular axis is parallel to the polarization vector of the laser field. The MPI rates are computed for a wide range of internuclear separations R with high resolution in R and reproduce resonance and near-threshold structures. We show that enhancement of ionization at critical internuclear separations is related to resonance series with higher electronic states. The effect of two-centre interference on the MPI signal is discussed.

  6. The BL-QMR algorithm for non-Hermitian linear systems with multiple right-hand sides

    Energy Technology Data Exchange (ETDEWEB)

    Freund, R.W. [AT& T Bell Labs., Murray Hill, NJ (United States)

    1996-12-31

    Many applications require the solution of multiple linear systems that have the same coefficient matrix, but differ in their right-hand sides. Instead of applying an iterative method to each of these systems individually, it is potentially much more efficient to employ a block version of the method that generates iterates for all the systems simultaneously. However, it is quite intricate to develop robust and efficient block iterative methods. In particular, a key issue in the design of block iterative methods is the need for deflation. The iterates for the different systems that are produced by a block method will, in general, converge at different stages of the block iteration. An efficient and robust block method needs to be able to detect and then deflate converged systems. Each such deflation reduces the block size, and thus the block method needs to be able to handle varying block sizes. For block Krylov-subspace methods, deflation is also crucial in order to delete linearly and almost linearly dependent vectors in the underlying block Krylov sequences. An added difficulty arises for Lanczos-type block methods for non-Hermitian systems, since they involve two different block Krylov sequences. In these methods, deflation can now occur independently in both sequences, and consequently, the block sizes in the two sequences may become different in the course of the iteration, even though they were identical at the beginning. We present a block version of Freund and Nachtigal`s quasi-minimal residual method for the solution of non-Hermitian linear systems with single right-hand sides.

  7. Unidirectional reflectionless phenomena in a non-Hermitian quantum system of quantum dots coupled to a plasmonic waveguide.

    Science.gov (United States)

    Wu, Nan; Zhang, Cong; Jin, Xing Ri; Zhang, Ying Qiao; Lee, YoungPak

    2018-02-19

    Unidirectional reflectionless phenomena are investigated theoretically in a non-Hermitian quantum system composed of several quantum dots and a plasmonic waveguide. By adjusting the phase shifts between quantum dots, single- and dual-band unidirectional reflectionlessnesses are realized at exceptional points based on two and three quantum dots coupled to a plasmonic waveguide, respectively. In addition, single- and dual-band unidirectional perfect absorptions with high quality factors are obtained at the vicinity of exceptional points.

  8. X-ray absorption in insulators with non-Hermitian real-time time-dependent density functional theory.

    Science.gov (United States)

    Fernando, Ranelka G; Balhoff, Mary C; Lopata, Kenneth

    2015-02-10

    Non-Hermitian real-time time-dependent density functional theory was used to compute the Si L-edge X-ray absorption spectrum of α-quartz using an embedded finite cluster model and atom-centered basis sets. Using tuned range-separated functionals and molecular orbital-based imaginary absorbing potentials, the excited states spanning the pre-edge to ∼20 eV above the ionization edge were obtained in good agreement with experimental data. This approach is generalizable to TDDFT studies of core-level spectroscopy and dynamics in a wide range of materials.

  9. Investigation of the existence and uniqueness of extremal and positive definite solutions of nonlinear matrix equations

    Directory of Open Access Journals (Sweden)

    Abdel-Shakoor M Sarhan

    2016-05-01

    Full Text Available Abstract We consider two nonlinear matrix equations X r ± ∑ i = 1 m A i ∗ X δ i A i = I $X^{r} \\pm \\sum_{i = 1}^{m} A_{i}^{*}X^{\\delta_{i}}A_{i} = I$ , where − 1 < δ i < 0 $- 1 < \\delta_{i} < 0$ , and r, m are positive integers. For the first equation (plus case, we prove the existence of positive definite solutions and extremal solutions. Two algorithms and proofs of their convergence to the extremal positive definite solutions are constructed. For the second equation (negative case, we prove the existence and the uniqueness of a positive definite solution. Moreover, the algorithm given in (Duan et al. in Linear Algebra Appl. 429:110-121, 2008 (actually, in (Shi et al. in Linear Multilinear Algebra 52:1-15, 2004 for r = 1 $r = 1$ is proved to be valid for any r. Numerical examples are given to illustrate the performance and effectiveness of all the constructed algorithms. In Appendix, we analyze the ordering on the positive cone P ( n ‾ $\\overline{P(n}$ .

  10. A symmetric positive definite formulation for monolithic fluid structure interaction

    KAUST Repository

    Robinson-Mosher, Avi; Schroeder, Craig; Fedkiw, Ronald

    2011-01-01

    In this paper we consider a strongly coupled (monolithic) fluid structure interaction framework for incompressible flow, as opposed to a loosely coupled (partitioned) method. This requires solving a single linear system that combines the unknown velocities of the structure with the unknown pressures of the fluid. In our previous work, we were able to obtain a symmetric formulation of this coupled system; however, it was also indefinite, making it more difficult to solve. In fact in practice there have been cases where we have been unable to invert the system. In this paper we take a novel approach that consists of factoring the damping matrix of deformable structures and show that this can be used to obtain a symmetric positive definite system, at least to the extent that the uncoupled systems were symmetric positive definite. We use a traditional MAC grid discretization of the fluid and a fully Lagrangian discretization of the structures for the sake of exposition, noting that our procedure can be generalized to other scenarios. For the special case of rigid bodies, where there are no internal damping forces, we exactly recover the system of Batty et al. (2007) [4]. © 2010 Elsevier Inc.

  11. A symmetric positive definite formulation for monolithic fluid structure interaction

    KAUST Repository

    Robinson-Mosher, Avi

    2011-02-01

    In this paper we consider a strongly coupled (monolithic) fluid structure interaction framework for incompressible flow, as opposed to a loosely coupled (partitioned) method. This requires solving a single linear system that combines the unknown velocities of the structure with the unknown pressures of the fluid. In our previous work, we were able to obtain a symmetric formulation of this coupled system; however, it was also indefinite, making it more difficult to solve. In fact in practice there have been cases where we have been unable to invert the system. In this paper we take a novel approach that consists of factoring the damping matrix of deformable structures and show that this can be used to obtain a symmetric positive definite system, at least to the extent that the uncoupled systems were symmetric positive definite. We use a traditional MAC grid discretization of the fluid and a fully Lagrangian discretization of the structures for the sake of exposition, noting that our procedure can be generalized to other scenarios. For the special case of rigid bodies, where there are no internal damping forces, we exactly recover the system of Batty et al. (2007) [4]. © 2010 Elsevier Inc.

  12. The complex Laguerre symplectic ensemble of non-Hermitian matrices

    International Nuclear Information System (INIS)

    Akemann, G.

    2005-01-01

    We solve the complex extension of the chiral Gaussian symplectic ensemble, defined as a Gaussian two-matrix model of chiral non-Hermitian quaternion real matrices. This leads to the appearance of Laguerre polynomials in the complex plane and we prove their orthogonality. Alternatively, a complex eigenvalue representation of this ensemble is given for general weight functions. All k-point correlation functions of complex eigenvalues are given in terms of the corresponding skew orthogonal polynomials in the complex plane for finite-N, where N is the matrix size or number of eigenvalues, respectively. We also allow for an arbitrary number of complex conjugate pairs of characteristic polynomials in the weight function, corresponding to massive quark flavours in applications to field theory. Explicit expressions are given in the large-N limit at both weak and strong non-Hermiticity for the weight of the Gaussian two-matrix model. This model can be mapped to the complex Dirac operator spectrum with non-vanishing chemical potential. It belongs to the symmetry class of either the adjoint representation or two colours in the fundamental representation using staggered lattice fermions

  13. Non-Hermitian multi-particle systems from complex root spaces

    International Nuclear Information System (INIS)

    Fring, Andreas; Smith, Monique

    2012-01-01

    We provide a general construction procedure for antilinearly invariant complex root spaces. The proposed method is generic and may be applied to any Weyl group allowing us to take any element of the group as a starting point for the construction. Worked-out examples for several specific Weyl groups are presented, focusing especially on those cases for which no solutions were found previously. When applied to the defining relations of models based on root systems, this usually leads to non-Hermitian models, which are nonetheless physically viable in a self-consistent sense as they are antilinearly invariant by construction. We discuss new types of Calogero models based on these complex roots. In addition, we propose an alternative construction leading to q-deformed roots. We employ the latter type of roots to formulate a new version of affine Toda field theories based on non-simply laced root systems. These models exhibit on the classical level a strong–weak duality in the coupling constant equivalent to a Lie algebraic duality, which is known for the quantum version of the undeformed case. (paper)

  14. Positive Behavior Support: A Proposal for Updating and Refining the Definition

    Science.gov (United States)

    Kincaid, Don; Dunlap, Glen; Kern, Lee; Lane, Kathleen Lynne; Bambara, Linda M.; Brown, Fredda; Fox, Lise; Knoster, Timothy P.

    2016-01-01

    Positive behavior support (PBS) has been a dynamic and growing enterprise for more than 25 years. During this period, PBS has expanded applications across a wide range of populations and multiple levels of implementation. As a result, there have been understandable inconsistencies and confusion regarding the definition of PBS. In this essay, we…

  15. The effect of a non-hermitian crystal potential on the scattering matrix in reflection electron diffraction

    International Nuclear Information System (INIS)

    Smith, A.E.; Josefsson, T.W.

    1994-01-01

    An extension to include general inelastic scattering effects is developed for the case of reflection electron diffraction scattering from surfaces. In this extension of work by Lynch and Moodie, it is shown how the resultant non-Hermitian matrix problem can be recast in a form that is suitable for computation. In particular, a computational method is outlined based on techniques developed by Eberlein for matrix diagonalisation using complex rotations and shears. The resultant methods are applied to the problem of Convergent Beam RHEED. 23 refs., 3 figs

  16. Is the concept of the non-Hermitian effective Hamiltonian relevant in the case of potential scattering?

    International Nuclear Information System (INIS)

    Savin, Dmitry V.; Sokolov, Valentin V.; Sommers, Hans-Juergen

    2003-01-01

    We examine the notion and properties of the non-Hermitian effective Hamiltonian of an unstable system using as an example potential resonance scattering with a fixed angular momentum. We present a consistent self-adjoint formulation of the problem of scattering on a finite-range potential, which is based on the separation of the configuration space into two segments, internal and external. The scattering amplitude is expressed in terms of the resolvent of a non-Hermitian operator H. The explicit form of this operator depends on both the radius of separation and the boundary conditions at this place, which can be chosen in many different ways. We discuss this freedom and show explicitly that the physical scattering amplitude is, nevertheless, unique, although not all choices are equally adequate from the physical point of view. The energy-dependent operator H should not be confused with the non-Hermitian effective Hamiltonian H eff which is usually exploited to describe interference of overlapping resonances. We note that the simple Breit-Wigner approximation is as a rule valid for any individual resonance in the case of few-channel scattering on a flat billiardlike cavity, leaving no room for nontrivial H eff to appear. The physics is appreciably richer in the case of an open chain of L connected similar cavities whose spectrum has a band structure. For a fixed band of L overlapping resonances, the smooth energy dependence of H can be ignored so that the constant LxL submatrix H eff approximately describes the time evolution of the chain in the energy domain of the band and the complex eigenvalues of H eff define the energies and widths of the resonances. We apply the developed formalism to the problem of a chain of L δ barriers, whose solution is also found independently in a closed form. We construct H eff for the two commonly considered types of boundary conditions (Neumann and Dirichlet) for the internal motion. Although the final results are in perfect

  17. Covariant loops and strings in a positive definite Hilbert space

    International Nuclear Information System (INIS)

    Rohrlich, F.

    1977-01-01

    Relativistic loops and strings are defined in the conventional way as solutions of a one-dimensional wave equation with certain boundary conditions and satisfying the orthogonal gauge conditions. Conventional pseudo-Cartesian co-ordinates (rather than null-plane co-ordinates) are used. The creation and annihilation operator four-vector αsub(μ)sup(+) and αsub(m) are required to be spacelike (orthogonal to the total momentum Psup(μ), so that the resulting Fock space is positive definite. This requirements is shown to be mathematically consistent with Poincare' invariance and to impose no additional physical constraints on the system. It can be implemented in a canonical realization of the Poincare' algebra as a condition on a state vectors, or in a noncanonical realization as an operator equation, as is done here. The space is further restricted by the Virasoro conditions to a physical subspace PHI which is of course also positive definite. In this way there arises no critical-dimension problem and Poincare' invariance holds also in 3+1 dimensions. The energy and spin spectra are the same as usual, leading to linear Regge trajectories, except that there are no tachyons and no zero mass states. The leading Regge trajectory has negative intercept

  18. Descriptions of spinal MRI lesions and definition of a positive MRI of the spine in axial spondyloarthritis

    DEFF Research Database (Denmark)

    Hermann, Kay-Geert A; Baraliakos, Xenofon; van der Heijde, Désirée M F M

    2012-01-01

    The aim of this study was to define characteristic MRI findings in the spine of patients with axial spondyloarthritis (SpA) and provide a definition of a positive spinal MRI for inflammation and structural changes.......The aim of this study was to define characteristic MRI findings in the spine of patients with axial spondyloarthritis (SpA) and provide a definition of a positive spinal MRI for inflammation and structural changes....

  19. Incomplete factorization technique for positive definite linear systems

    International Nuclear Information System (INIS)

    Manteuffel, T.A.

    1980-01-01

    This paper describes a technique for solving the large sparse symmetric linear systems that arise from the application of finite element methods. The technique combines an incomplete factorization method called the shifted incomplete Cholesky factorization with the method of generalized conjugate gradients. The shifted incomplete Cholesky factorization produces a splitting of the matrix A that is dependent upon a parameter α. It is shown that if A is positive definite, then there is some α for which this splitting is possible and that this splitting is at least as good as the Jacobi splitting. The method is shown to be more efficient on a set of test problems than either direct methods or explicit iteration schemes

  20. Proceedings – Mathematical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Let be a compact Riemann surface of genus g ≥ 1 , 1 , … , g be a basis of holomorphic 1-forms on and let H = ( h i j ) i , j = 1 g be a positive definite Hermitian matrix. It is well known that the metric defined as d s H 2 = ∑ i , j = 1 g h i j i ⊗ j ¯ is a K\\"a hler metric on of non-positive curvature. Let K H : C → R be ...

  1. Nonlinear transient heat transfer and thermoelastic analysis of thick-walled FGM cylinder with temperature-dependent material properties using Hermitian transfinite element

    Energy Technology Data Exchange (ETDEWEB)

    Azadi, Mohammad [Sharif University of Technology, Tehran (Iran, Islamic Republic of); Azadi, Mahboobeh [Shiraz University, Shiraz (Iran, Islamic Republic of)

    2009-10-15

    Nonlinear transient heat transfer and thermoelastic stress analyses of a thick-walled FGM cylinder with temperature dependent materials are performed by using the Hermitian transfinite element method. Temperature-dependency of the material properties has not been taken into account in transient thermoelastic analysis, so far. Due to the mentioned dependency, the resulting governing FEM equations of transient heat transfer are highly nonlinear. Furthermore, in all finite element analysis performed so far in the field, Lagrangian elements have been used. To avoid an artificial local heat source at the mutual boundaries of the elements, Hermitian elements are used instead in the present research. Another novelty of the present paper is simultaneous use of the transfinite element method and updating technique. Time variations of the temperature, displacements, and stresses are obtained through a numerical Laplace inversion. Finally, results obtained considering the temperature-dependency of the material properties are compared with those derived based on temperature independency assumption. Furthermore, the temperature distribution and the radial and circumferential stresses are investigated versus time, geometrical parameters and index of power law. Results reveal that the temperature-dependency effect is significant

  2. Non-Hermitian localization in biological networks.

    Science.gov (United States)

    Amir, Ariel; Hatano, Naomichi; Nelson, David R

    2016-04-01

    We explore the spectra and localization properties of the N-site banded one-dimensional non-Hermitian random matrices that arise naturally in sparse neural networks. Approximately equal numbers of random excitatory and inhibitory connections lead to spatially localized eigenfunctions and an intricate eigenvalue spectrum in the complex plane that controls the spontaneous activity and induced response. A finite fraction of the eigenvalues condense onto the real or imaginary axes. For large N, the spectrum has remarkable symmetries not only with respect to reflections across the real and imaginary axes but also with respect to 90^{∘} rotations, with an unusual anisotropic divergence in the localization length near the origin. When chains with periodic boundary conditions become directed, with a systematic directional bias superimposed on the randomness, a hole centered on the origin opens up in the density-of-states in the complex plane. All states are extended on the rim of this hole, while the localized eigenvalues outside the hole are unchanged. The bias-dependent shape of this hole tracks the bias-independent contours of constant localization length. We treat the large-N limit by a combination of direct numerical diagonalization and using transfer matrices, an approach that allows us to exploit an electrostatic analogy connecting the "charges" embodied in the eigenvalue distribution with the contours of constant localization length. We show that similar results are obtained for more realistic neural networks that obey "Dale's law" (each site is purely excitatory or inhibitory) and conclude with perturbation theory results that describe the limit of large directional bias, when all states are extended. Related problems arise in random ecological networks and in chains of artificial cells with randomly coupled gene expression patterns.

  3. The area distribution of two-dimensional random walks and non-Hermitian Hofstadter quantum mechanics

    International Nuclear Information System (INIS)

    Matveenko, Sergey; Ouvry, Stéphane

    2014-01-01

    When random walks on a square lattice are biased horizontally to move solely to the right, the probability distribution of their algebraic area can be obtained exactly (Mashkevich and Ouvry 2009 J. Stat. Phys. 137 71). We explicitly map this biased classical random system onto a non-Hermitian Hofstadter-like quantum model where a charged particle on a square lattice coupled to a perpendicular magnetic field hops only to the right. For the commensurate case, when the magnetic flux per unit cell is rational, an exact solution of the quantum model is obtained. The periodicity of the lattice allows one to relate traces of the Nth power of the Hamiltonian to probability distribution generating functions of biased walks of length N. (paper)

  4. Positive-definite functions and unitary representations of locally compact groups in a Hilbert space

    International Nuclear Information System (INIS)

    Gali, I.M.; Okb el-Bab, A.S.; Hassan, H.M.

    1977-08-01

    It is proved that the necessary and sufficient condition for the existence of an integral representation of a group of unitary operators in a Hilbert space is that it is positive-definite and continuous in some topology

  5. Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields

    Energy Technology Data Exchange (ETDEWEB)

    Puthumpally-Joseph, Raiju; Charron, Eric [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay (France); Sukharev, Maxim [Science and Mathematics Faculty, College of Letters and Sciences, Arizona State University, Mesa, Arizona 85212 (United States)

    2016-04-21

    We introduce a non-Hermitian Schrödinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.

  6. Approximation of a solution for a K-positive definite operator equation

    International Nuclear Information System (INIS)

    Chidume, C.E.; Osilike, M.O.

    1994-11-01

    Let E be a separable q-uniformly smooth Banach space, q > 1, and let A : D(A) is contained in-bar E → E be a K-positive definite operator. Let f is an element of E be arbitrary. An iterative method is constructed which converges strongly to the unique solution of the equation Ax = f. Our result resolves two questions raised in Chidume and Aneke (Applicable Analysis Vol. 50 (1993), p. 293). (author). 13 refs

  7. Schwinger-Dyson loop equations as the w1+∞-like constraints for hermitian multi-matrix chain model at finite N

    International Nuclear Information System (INIS)

    Cheng, Yi-Xin

    1992-01-01

    The Schwinger-Dyson loop equations for the hermitian multi-matrix chain models at finite N, are derived from the Ward identities of the partition functional under the infinitesimal field transformations. The constraint operators W n (m) satisfy the w 1+∞ -like algebra up to a linear combination of the lower spin operators. We find that the all the higher spin constraints are reducible to the Virasoro-type constraints for all the matrix chain models. (author)

  8. Construction of a unique metric in quasi-Hermitian quantum mechanics: Nonexistence of the charge operator in a 2 x 2 matrix model (vol 640, pg 52, 2006)

    Czech Academy of Sciences Publication Activity Database

    Znojil, Miloslav; Geyer, HB.

    2007-01-01

    Roč. 649, 5-6 (2007), s. 494-494 ISSN 0370-2693 R&D Projects: GA ČR GA202/07/1307 Institutional research plan: CEZ:AV0Z10480505 Keywords : metrics * quasi-Hermitian * charge Subject RIV: BE - Theoretical Physics Impact factor: 4.189, year: 2007

  9. Fock model and Segal-Bargmann transform for minimal representations of Hermitian Lie groups

    DEFF Research Database (Denmark)

    Hilgert, Joachim; Kobayashi, Toshiyuki; Möllers, Jan

    2012-01-01

    For any Hermitian Lie group G of tube type we construct a Fock model of its minimal representation. The Fock space is defined on the minimal nilpotent K_C-orbit X in p_C and the L^2-inner product involves a K-Bessel function as density. Here K is a maximal compact subgroup of G, and g......_C=k_C+p_C is a complexified Cartan decomposition. In this realization the space of k-finite vectors consists of holomorphic polynomials on X. The reproducing kernel of the Fock space is calculated explicitly in terms of an I-Bessel function. We further find an explicit formula of a generalized Segal-Bargmann transform which...... intertwines the Schroedinger and Fock model. Its kernel involves the same I-Bessel function. Using the Segal--Bargmann transform we also determine the integral kernel of the unitary inversion operator in the Schroedinger model which is given by a J-Bessel function....

  10. An algorithm to compute the square root of 3x3 positive definite matrix

    International Nuclear Information System (INIS)

    Franca, L.P.

    1988-06-01

    An efficient closed form to compute the square root of a 3 x 3 positive definite matrix is presented. The derivation employs the Cayley-Hamilton theorem avoiding calculation of eigenvectors. We show that evaluation of one eigenvalue of the square root matrix is needed and can not be circumvented. The algorithm is robust and efficient. (author) [pt

  11. Development of a definition for Rapid Progression (RP) of renal function in HIV-positive persons

    DEFF Research Database (Denmark)

    Kamara, David A; Nielsen, Lene Ryom; Ross, Michael

    2014-01-01

    No consensus exists on how to define abnormally rapid deterioration in renal function (Rapid Progression, RP). We developed an operational definition of RP in HIV-positive persons with baseline estimated glomerular filtration rate (eGFR) >90ml/min/1.73m2 (using Cockcroft Gault) in the Data...

  12. Legal positions of the Constitutional Court of Ukraine: main signs and definition

    Directory of Open Access Journals (Sweden)

    Romana Reva

    2016-04-01

    the Constitutional Court of Ukraine, the legal positions have a feature of the relative finality. Basing on the research results, by the author there is offered the following definition. The legal positions of the Constitutional Court of Ukraine are legal conclusions of the Court due to the interpretation of the Constitution of Ukraine and/ or provisions of laws and other regulations within its competence, which remove the constitutional and legal uncertainty, which have general character, particular legal force and which is the legal basis for a final decision, set in the Court act. The author concludes that the most reasonable approach is to formulate the definition of the legal positions of the Constitutional Court of Ukraine on the basis of objective main features of this phenomenon. Its further separate detailed study requires the issue of validity of the legal positions of the Constitutional Court of Ukraine.

  13. A look-ahead variant of the Lanczos algorithm and its application to the quasi-minimal residual method for non-Hermitian linear systems. Ph.D. Thesis - Massachusetts Inst. of Technology, Aug. 1991

    Science.gov (United States)

    Nachtigal, Noel M.

    1991-01-01

    The Lanczos algorithm can be used both for eigenvalue problems and to solve linear systems. However, when applied to non-Hermitian matrices, the classical Lanczos algorithm is susceptible to breakdowns and potential instabilities. In addition, the biconjugate gradient (BCG) algorithm, which is the natural generalization of the conjugate gradient algorithm to non-Hermitian linear systems, has a second source of breakdowns, independent of the Lanczos breakdowns. Here, we present two new results. We propose an implementation of a look-ahead variant of the Lanczos algorithm which overcomes the breakdowns by skipping over those steps where a breakdown or a near-breakdown would occur. The new algorithm can handle look-ahead steps of any length and requires the same number of matrix-vector products and inner products per step as the classical Lanczos algorithm without look-ahead. Based on the proposed look-ahead Lanczos algorithm, we then present a novel BCG-like approach, the quasi-minimal residual (QMR) method, which avoids the second source of breakdowns in the BCG algorithm. We present details of the new method and discuss some of its properties. In particular, we discuss the relationship between QMR and BCG, showing how one can recover the BCG iterates, when they exist, from the QMR iterates. We also present convergence results for QMR, showing the connection between QMR and the generalized minimal residual (GMRES) algorithm, the optimal method in this class of methods. Finally, we give some numerical examples, both for eigenvalue computations and for non-Hermitian linear systems.

  14. Bayesian Nonparametric Clustering for Positive Definite Matrices.

    Science.gov (United States)

    Cherian, Anoop; Morellas, Vassilios; Papanikolopoulos, Nikolaos

    2016-05-01

    Symmetric Positive Definite (SPD) matrices emerge as data descriptors in several applications of computer vision such as object tracking, texture recognition, and diffusion tensor imaging. Clustering these data matrices forms an integral part of these applications, for which soft-clustering algorithms (K-Means, expectation maximization, etc.) are generally used. As is well-known, these algorithms need the number of clusters to be specified, which is difficult when the dataset scales. To address this issue, we resort to the classical nonparametric Bayesian framework by modeling the data as a mixture model using the Dirichlet process (DP) prior. Since these matrices do not conform to the Euclidean geometry, rather belongs to a curved Riemannian manifold,existing DP models cannot be directly applied. Thus, in this paper, we propose a novel DP mixture model framework for SPD matrices. Using the log-determinant divergence as the underlying dissimilarity measure to compare these matrices, and further using the connection between this measure and the Wishart distribution, we derive a novel DPM model based on the Wishart-Inverse-Wishart conjugate pair. We apply this model to several applications in computer vision. Our experiments demonstrate that our model is scalable to the dataset size and at the same time achieves superior accuracy compared to several state-of-the-art parametric and nonparametric clustering algorithms.

  15. On conjugate gradient type methods and polynomial preconditioners for a class of complex non-Hermitian matrices

    Science.gov (United States)

    Freund, Roland

    1988-01-01

    Conjugate gradient type methods are considered for the solution of large linear systems Ax = b with complex coefficient matrices of the type A = T + i(sigma)I where T is Hermitian and sigma, a real scalar. Three different conjugate gradient type approaches with iterates defined by a minimal residual property, a Galerkin type condition, and an Euclidian error minimization, respectively, are investigated. In particular, numerically stable implementations based on the ideas behind Paige and Saunder's SYMMLQ and MINRES for real symmetric matrices are proposed. Error bounds for all three methods are derived. It is shown how the special shift structure of A can be preserved by using polynomial preconditioning. Results on the optimal choice of the polynomial preconditioner are given. Also, some numerical experiments for matrices arising from finite difference approximations to the complex Helmholtz equation are reported.

  16. False-positive positron emission tomography appearance with 18F-fluorodeoxyglucose after definitive radiotherapy for cancer of the mobile tongue.

    Science.gov (United States)

    Ariji, Y; Fuwa, N; Kodaira, T; Tachibana, H; Nakamura, T; Satoh, Y; Ariji, E

    2009-01-01

    (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) is an effective tool for evaluating the results of radiotherapy. However, some false-positive appearances caused by physiological or pathological accumulation are reported. We report on three patients who showed a high accumulation of FDG in the lingual muscles but had no recurrent tumour after definitive radiotherapy for the mobile tongue. All patients had squamous cell carcinoma of the tongue and received interstitial radiotherapy with small sources. High uptake was seen in the lingual muscles without recurrence or inflammation, based on physical and MR examinations. This false-positive appearance is thought to relate to ill-balanced high activity of the lingual muscles after definitive radiotherapy.

  17. Generalized space and linear momentum operators in quantum mechanics

    International Nuclear Information System (INIS)

    Costa, Bruno G. da; Borges, Ernesto P.

    2014-01-01

    We propose a modification of a recently introduced generalized translation operator, by including a q-exponential factor, which implies in the definition of a Hermitian deformed linear momentum operator p ^ q , and its canonically conjugate deformed position operator x ^ q . A canonical transformation leads the Hamiltonian of a position-dependent mass particle to another Hamiltonian of a particle with constant mass in a conservative force field of a deformed phase space. The equation of motion for the classical phase space may be expressed in terms of the generalized dual q-derivative. A position-dependent mass confined in an infinite square potential well is shown as an instance. Uncertainty and correspondence principles are analyzed

  18. Central line-associated bloodstream infections in adult hematology patients with febrile neutropenia: an evaluation of surveillance definitions using differential time to blood culture positivity.

    Science.gov (United States)

    Freeman, Joshua T; Elinder-Camburn, Anna; McClymont, Catherine; Anderson, Deverick J; Bilkey, Mary; Williamson, Deborah A; Berkahn, Leanne; Roberts, Sally A

    2013-01-01

    We used differential time to positivity between central and peripheral blood cultures to evaluate the positive predictive value (PPV) of the National Healthcare Safety Network central line-associated bloodstream infection (CLABSI) surveillance definition among hematology patients with febrile neutropenia. The PPV was 27.7%, which suggests that, when the definition is applied to this population, CLABSI rates will be substantially overestimated.

  19. Sputum, sex and scanty smears: new case definition may reduce sex disparities in smear-positive tuberculosis.

    Science.gov (United States)

    Ramsay, A; Bonnet, M; Gagnidze, L; Githui, W; Varaine, F; Guérin, P J

    2009-05-01

    Urban clinic, Nairobi. To evaluate the impact of specimen quality and different smear-positive tuberculosis (TB) case (SPC) definitions on SPC detection by sex. Prospective study among TB suspects. A total of 695 patients were recruited: 644 produced > or =1 specimen for microscopy. The male/female sex ratio was 0.8. There were no significant differences in numbers of men and women submitting three specimens (274/314 vs. 339/380, P = 0.43). Significantly more men than women produced a set of three 'good' quality specimens (175/274 vs. 182/339, P = 0.01). Lowering thresholds for definitions to include scanty smears resulted in increases in SPC detection in both sexes; the increase was significantly higher for women. The revised World Health Organization (WHO) case definition was associated with the highest detection rates in women. When analysis was restricted only to patients submitting 'good' quality specimen sets, the difference in detection between sexes was on the threshold for significance (P = 0.05). Higher SPC notification rates in men are commonly reported by TB control programmes. The revised WHO SPC definition may reduce sex disparities in notification. This should be considered when evaluating other interventions aimed at reducing these. Further study is required on the effects of the human immuno-deficiency virus and instructed specimen collection on sex-specific impact of new SPC definition.

  20. Extensions of positive definite functions applications and their harmonic analysis

    CERN Document Server

    Jorgensen, Palle E T; Tian, Feng

    2016-01-01

    This monograph deals with the mathematics of extending given partial data-sets obtained from experiments; Experimentalists frequently gather spectral data when the observed data is limited, e.g., by the precision of instruments; or by other limiting external factors. Here the limited information is a restriction, and the extensions take the form of full positive definite function on some prescribed group. It is therefore both an art and a science to produce solid conclusions from restricted or limited data. While the theory of is important in many areas of pure and applied mathematics, it is difficult for students and for the novice to the field, to find accessible presentations which cover all relevant points of view, as well as stressing common ideas and interconnections. We have aimed at filling this gap, and we have stressed hands-on-examples.

  1. A projected preconditioned conjugate gradient algorithm for computing many extreme eigenpairs of a Hermitian matrix

    International Nuclear Information System (INIS)

    Vecharynski, Eugene; Yang, Chao; Pask, John E.

    2015-01-01

    We present an iterative algorithm for computing an invariant subspace associated with the algebraically smallest eigenvalues of a large sparse or structured Hermitian matrix A. We are interested in the case in which the dimension of the invariant subspace is large (e.g., over several hundreds or thousands) even though it may still be small relative to the dimension of A. These problems arise from, for example, density functional theory (DFT) based electronic structure calculations for complex materials. The key feature of our algorithm is that it performs fewer Rayleigh–Ritz calculations compared to existing algorithms such as the locally optimal block preconditioned conjugate gradient or the Davidson algorithm. It is a block algorithm, and hence can take advantage of efficient BLAS3 operations and be implemented with multiple levels of concurrency. We discuss a number of practical issues that must be addressed in order to implement the algorithm efficiently on a high performance computer

  2. The consequences of non-normality

    International Nuclear Information System (INIS)

    Hip, I.; Lippert, Th.; Neff, H.; Schilling, K.; Schroers, W.

    2002-01-01

    The non-normality of Wilson-type lattice Dirac operators has important consequences - the application of the usual concepts from the textbook (hermitian) quantum mechanics should be reconsidered. This includes an appropriate definition of observables and the refinement of computational tools. We show that the truncated singular value expansion is the optimal approximation to the inverse operator D -1 and we prove that due to the γ 5 -hermiticity it is equivalent to γ 5 times the truncated eigenmode expansion of the hermitian Wilson-Dirac operator

  3. The development of an algebraic multigrid algorithm for symmetric positive definite linear systems

    Energy Technology Data Exchange (ETDEWEB)

    Vanek, P.; Mandel, J.; Brezina, M. [Univ. of Colorado, Denver, CO (United States)

    1996-12-31

    An algebraic multigrid algorithm for symmetric, positive definite linear systems is developed based on the concept of prolongation by smoothed aggregation. Coarse levels are generated automatically. We present a set of requirements motivated heuristically by a convergence theory. The algorithm then attempts to satisfy the requirements. Input to the method are the coefficient matrix and zero energy modes, which are determined from nodal coordinates and knowledge of the differential equation. Efficiency of the resulting algorithm is demonstrated by computational results on real world problems from solid elasticity, plate blending, and shells.

  4. The rank of a normally distributed matrix and positive definiteness of a noncentral Wishart distributed matrix

    NARCIS (Netherlands)

    Steerneman, A. G. M.; van Perlo-ten Kleij, Frederieke

    2008-01-01

    If X similar to N-nxk(M, I-n circle times Sigma), then S = X'X has the noncentral Wishart distribution W-k(')(n, Sigma; A), where Lambda = M'M. Here Sigma is allowed to be singular. It is well known that if Lambda = 0, then S has a (central) Wishart distribution and. S is positive definite with

  5. LINPACK, Subroutine Library for Linear Equation System Solution and Matrix Calculation

    International Nuclear Information System (INIS)

    Dongarra, J.J.

    1979-01-01

    1 - Description of problem or function: LINPACK is a collection of FORTRAN subroutines which analyze and solve various classes of systems of simultaneous linear algebraic equations. The collection deals with general, banded, symmetric indefinite, symmetric positive definite, triangular, and tridiagonal square matrices, as well as with least squares problems and the QR and singular value decompositions of rectangular matrices. A subroutine-naming convention is employed in which each subroutine name consists of five letters which represent a coded specification (TXXYY) of the computation done by that subroutine. The first letter, T, indicates the matrix data type. Standard FORTRAN allows the use of three such types: S REAL, D DOUBLE PRECISION, and C COMPLEX. In addition, some FORTRAN systems allow a double-precision complex type: Z COMPLEX*16. The second and third letters of the subroutine name, XX, indicate the form of the matrix or its decomposition: GE: General, GB: General band, PO: Positive definite, PP: Positive definite packed, PB: Positive definite band, SI: Symmetric indefinite, SP: Symmetric indefinite packed, HI: Hermitian indefinite, HP: Hermitian indefinite packed, TR: Triangular, GT: General tridiagonal, PT: Positive definite tridiagonal, CH: Cholesky decomposition, QR: Orthogonal-triangular decomposition, SV: Singular value decomposition. The final two letters, YY, indicate the computation done by the particular subroutine: FA: Factor, CO: Factor and estimate condition, SL: Solve, DI: Determinant and/or inverse and/or inertia, DC: Decompose, UD: Update, DD: Down-date, EX Exchange. The following chart shows all the LINPACK subroutines. The initial 'S' in the names may be replaced by D, C or Z and the initial 'C' in the complex-only names may be replaced by a Z. SGE: FA, CO, SL, DI; SGB: FA, CO, SL, DI; SPO: FA, CO, SL, DI; SPP: FA, CO, SL, DI; SPB: FA, CO, SL, DI; SSI: FA, CO, SL, DI; SSP: FA, CO, SL, DI; CHI: FA, CO, SL, DI; CHP: FA, CO, SL, DI; STR

  6. Alternative structures and bi-Hamiltonian systems on a Hilbert space

    International Nuclear Information System (INIS)

    Marmo, G; Scolarici, G; Simoni, A; Ventriglia, F

    2005-01-01

    We discuss transformations generated by dynamical quantum systems which are bi-unitary, i.e. unitary with respect to a pair of Hermitian structures on an infinite-dimensional complex Hilbert space. We introduce the notion of Hermitian structures in generic relative position. We provide a few necessary and sufficient conditions for two Hermitian structures to be in generic relative position to better illustrate the relevance of this notion. The group of bi-unitary transformations is considered in both the generic and the non-generic case. Finally, we generalize the analysis to real Hilbert spaces and extend to infinite dimensions results already available in the framework of finite-dimensional linear bi-Hamiltonian systems

  7. Unveiling the significance of eigenvectors in diffusing non-Hermitian matrices by identifying the underlying Burgers dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Burda, Zdzislaw, E-mail: zdzislaw.burda@agh.edu.pl [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, PL-30059 Kraków (Poland); Grela, Jacek, E-mail: jacekgrela@gmail.com [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland); Nowak, Maciej A., E-mail: nowak@th.if.uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland); Tarnowski, Wojciech, E-mail: wojciech.tarnowski@uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland); Warchoł, Piotr, E-mail: piotr.warchol@uj.edu.pl [M. Smoluchowski Institute of Physics and Mark Kac Complex Systems Research Centre, Jagiellonian University, PL-30348 Kraków (Poland)

    2015-08-15

    Following our recent letter, we study in detail an entry-wise diffusion of non-hermitian complex matrices. We obtain an exact partial differential equation (valid for any matrix size N and arbitrary initial conditions) for evolution of the averaged extended characteristic polynomial. The logarithm of this polynomial has an interpretation of a potential which generates a Burgers dynamics in quaternionic space. The dynamics of the ensemble in the large N limit is completely determined by the coevolution of the spectral density and a certain eigenvector correlation function. This coevolution is best visible in an electrostatic potential of a quaternionic argument built of two complex variables, the first of which governs standard spectral properties while the second unravels the hidden dynamics of eigenvector correlation function. We obtain general formulas for the spectral density and the eigenvector correlation function for large N and for any initial conditions. We exemplify our studies by solving three examples, and we verify the analytic form of our solutions with numerical simulations.

  8. Hermitian symmetry free optical-single-carrier frequency division multiple access for visible light communication

    Science.gov (United States)

    Azim, Ali W.; Le Guennec, Yannis; Maury, Ghislaine

    2018-05-01

    Optical-orthogonal frequency division multiplexing (O-OFDM) is an effective scheme for visible light communications (VLC), offering a candid extension to multiple access (MA) scenarios, i.e., O-OFDMA. However, O-OFDMA exhibits high peak-to-average power ratio (PAPR), which exacerbates the non-linear distortions from the light emitting diode (LED). To overcome high PAPR while sustaining MA, optical-single-carrier frequency-division multiple access (O-SCFDMA) is used. For both O-OFDMA and O-SCFDMA, Hermitian symmetry (HS) constraint is imposed in frequency-domain (FD) to obtain a real-valued time-domain (TD) signal for intensity modulation-direct detection (IM-DD) implementation of VLC. Howbeit, HS results in an increase of PAPR for O-SCFDMA. In this regard, we propose HS free (HSF) O-SCFDMA (HSFO-SCFDMA). We compare HSFO-SCFDMA with several approaches in key parameters, such as, bit error rate (BER), optical power penalty, PAPR, quantization, electrical power efficiency and system complexity. BER performance and optical power penalty is evaluated considering multipath VLC channel and taking into account the bandwidth limitation of LED in combination with its optimized driver. It is illustrated that HSFO-SCFDMA outperforms other alternatives.

  9. Neck control after definitive radiochemotherapy without planned neck dissection in node-positive head and neck cancers

    International Nuclear Information System (INIS)

    Jang, Na Young; Lee, Keun-Wook; Ahn, Soon-Hyun; Kim, Jae-Sung; Ah Kim, In

    2012-01-01

    The purpose of this study was to evaluate neck control outcomes after definitive radiochemotherapy without planned neck dissection in node-positive head and neck cancer. We retrospectively reviewed medical records of fifty patients with node-positive head and neck cancer who received definitive radiochemotherapy. Twelve patients subsequently underwent neck dissection for suspicious recurrent or persistent disease. A median dose of 70 Gy (range 60-70.6) was delivered to involved nodes. Response evaluation was performed at a median of 5 weeks after completion of radiotherapy. Neck failure was observed in 11 patients and the 3-year regional control (RC) rate was 77.1%. Neck dissection was performed in 10 of the 11 patients; seven of these cases were successfully salvaged, and the ultimate rate of neck control was 92%. The remaining two patients who received neck dissection had negative pathologic results. On univariate analysis, initial nodal size > 2 cm, a less-than-complete response at the primary site, post-radiotherapy nodal size > 1.5 cm, and post-radiotherapy nodal necrosis were associated with RC. On multivariate analysis, less-than-complete primary site response and post-radiotherapy nodal necrosis were identified as independent prognostic factors for RC. The neck failure rate after definitive radiochemotherapy without planned neck dissection was 22%. Two-thirds of these were successfully salvaged with neck dissection and the ultimate neck control rate was 92%. Our results suggest that planned neck dissection might not be necessary in patients with complete response of primary site, no evidence of residual lesion > 1.5 cm, or no necrotic lymph nodes at the 1-2 months follow-up evaluation after radiotherapy

  10. LD Definition.

    Science.gov (United States)

    Learning Disability Quarterly, 1987

    1987-01-01

    The position paper (1981) of the National Joint Committee on Learning Disabilities presents a revised definition of learning disabilities and identifies issues and concerns (such as the limitation to children and the exclusion clause) associated with the definition included in P.L. 94-142, the Education for All Handicapped Children Act. (DB)

  11. Robust Solvers for Symmetric Positive Definite Operators and Weighted Poincaré Inequalities

    KAUST Repository

    Efendiev, Yalchin

    2012-01-01

    An abstract setting for robustly preconditioning symmetric positive definite (SPD) operators is presented. The term "robust" refers to the property of the condition numbers of the preconditioned systems being independent of mesh parameters and problem parameters. Important instances of such problem parameters are in particular (highly varying) coefficients. The method belongs to the class of additive Schwarz preconditioners. The paper gives an overview of the results obtained in a recent paper by the authors. It, furthermore, focuses on the importance of weighted Poincaré inequalities, whose notion is extended to general SPD operators, for the analysis of stable decompositions. To demonstrate the applicability of the abstract preconditioner the scalar elliptic equation and the stream function formulation of Brinkman\\'s equations in two spatial dimensions are considered. Several numerical examples are presented. © 2012 Springer-Verlag.

  12. Sputum, sex and scanty smears: new case definition may reduce sex disparities in smear-positive tuberculosis

    OpenAIRE

    Ramsay, A; Bonnet, M; Gagnidze, L; Githui, W; Varaine, F; Guérin, P J

    2009-01-01

    SETTING: Urban clinic, Nairobi. OBJECTIVES: To evaluate the impact of specimen quality and different smear-positive tuberculosis (TB) case (SPC) definitions on SPC detection by sex. DESIGN: Prospective study among TB suspects. RESULTS: A total of 695 patients were recruited: 644 produced > or =1 specimen for microscopy. The male/female sex ratio was 0.8. There were no significant differences in numbers of men and women submitting three specimens (274/314 vs. 339/380, P = 0.43). Significantly ...

  13. 5 CFR 534.602 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... in 5 U.S.C. 105, excluding the U.S. General Accounting Office. Head of an agency means the head of an... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Definitions. 534.602 Section 534.602... Administrative Appeals Judge Positions § 534.602 Definitions. Administrative appeals judge position means a...

  14. Convexity Conditions and the Legendre-Fenchel Transform for the Product of Finitely Many Positive Definite Quadratic Forms

    International Nuclear Information System (INIS)

    Zhao Yunbin

    2010-01-01

    While the product of finitely many convex functions has been investigated in the field of global optimization, some fundamental issues such as the convexity condition and the Legendre-Fenchel transform for the product function remain unresolved. Focusing on quadratic forms, this paper is aimed at addressing the question: When is the product of finitely many positive definite quadratic forms convex, and what is the Legendre-Fenchel transform for it? First, we show that the convexity of the product is determined intrinsically by the condition number of so-called 'scaled matrices' associated with quadratic forms involved. The main result claims that if the condition number of these scaled matrices are bounded above by an explicit constant (which depends only on the number of quadratic forms involved), then the product function is convex. Second, we prove that the Legendre-Fenchel transform for the product of positive definite quadratic forms can be expressed, and the computation of the transform amounts to finding the solution to a system of equations (or equally, finding a Brouwer's fixed point of a mapping) with a special structure. Thus, a broader question than the open 'Question 11' in Hiriart-Urruty (SIAM Rev. 49, 225-273, 2007) is addressed in this paper.

  15. Hermitian Yang-Mills equations and pseudo-holomorphic bundles on nearly Kaehler and nearly Calabi-Yau twistor 6-manifolds

    International Nuclear Information System (INIS)

    Popov, Alexander D.

    2010-01-01

    We consider the Hermitian Yang-Mills (HYM) equations for gauge potentials on a complex vector bundle E over an almost complex manifold X 6 which is the twistor space of an oriented Riemannian manifold M 4 . Each solution of the HYM equations on such X 6 defines a pseudo-holomorphic structure on the bundle E. It is shown that the pull-back to X 6 of any anti-self-dual gauge field on M 4 is a solution of the HYM equations on X 6 . This correspondence allows us to introduce new twistor actions for bosonic and supersymmetric Yang-Mills theories. As examples of X 6 we consider homogeneous nearly Kaehler and nearly Calabi-Yau manifolds which are twistor spaces of S 4 , CP 2 and B 4 , CB 2 (real 4-ball and complex 2-ball), respectively. Various explicit examples of solutions to the HYM equations on these spaces are provided. Applications in flux compactifications of heterotic strings are briefly discussed.

  16. Approximate joint diagonalization and geometric mean of symmetric positive definite matrices.

    Science.gov (United States)

    Congedo, Marco; Afsari, Bijan; Barachant, Alexandre; Moakher, Maher

    2014-01-01

    We explore the connection between two problems that have arisen independently in the signal processing and related fields: the estimation of the geometric mean of a set of symmetric positive definite (SPD) matrices and their approximate joint diagonalization (AJD). Today there is a considerable interest in estimating the geometric mean of a SPD matrix set in the manifold of SPD matrices endowed with the Fisher information metric. The resulting mean has several important invariance properties and has proven very useful in diverse engineering applications such as biomedical and image data processing. While for two SPD matrices the mean has an algebraic closed form solution, for a set of more than two SPD matrices it can only be estimated by iterative algorithms. However, none of the existing iterative algorithms feature at the same time fast convergence, low computational complexity per iteration and guarantee of convergence. For this reason, recently other definitions of geometric mean based on symmetric divergence measures, such as the Bhattacharyya divergence, have been considered. The resulting means, although possibly useful in practice, do not satisfy all desirable invariance properties. In this paper we consider geometric means of covariance matrices estimated on high-dimensional time-series, assuming that the data is generated according to an instantaneous mixing model, which is very common in signal processing. We show that in these circumstances we can approximate the Fisher information geometric mean by employing an efficient AJD algorithm. Our approximation is in general much closer to the Fisher information geometric mean as compared to its competitors and verifies many invariance properties. Furthermore, convergence is guaranteed, the computational complexity is low and the convergence rate is quadratic. The accuracy of this new geometric mean approximation is demonstrated by means of simulations.

  17. Approximate joint diagonalization and geometric mean of symmetric positive definite matrices.

    Directory of Open Access Journals (Sweden)

    Marco Congedo

    Full Text Available We explore the connection between two problems that have arisen independently in the signal processing and related fields: the estimation of the geometric mean of a set of symmetric positive definite (SPD matrices and their approximate joint diagonalization (AJD. Today there is a considerable interest in estimating the geometric mean of a SPD matrix set in the manifold of SPD matrices endowed with the Fisher information metric. The resulting mean has several important invariance properties and has proven very useful in diverse engineering applications such as biomedical and image data processing. While for two SPD matrices the mean has an algebraic closed form solution, for a set of more than two SPD matrices it can only be estimated by iterative algorithms. However, none of the existing iterative algorithms feature at the same time fast convergence, low computational complexity per iteration and guarantee of convergence. For this reason, recently other definitions of geometric mean based on symmetric divergence measures, such as the Bhattacharyya divergence, have been considered. The resulting means, although possibly useful in practice, do not satisfy all desirable invariance properties. In this paper we consider geometric means of covariance matrices estimated on high-dimensional time-series, assuming that the data is generated according to an instantaneous mixing model, which is very common in signal processing. We show that in these circumstances we can approximate the Fisher information geometric mean by employing an efficient AJD algorithm. Our approximation is in general much closer to the Fisher information geometric mean as compared to its competitors and verifies many invariance properties. Furthermore, convergence is guaranteed, the computational complexity is low and the convergence rate is quadratic. The accuracy of this new geometric mean approximation is demonstrated by means of simulations.

  18. Development of a definition for Rapid Progression (RP) of renal function in HIV-positive persons : the D:A:D study

    NARCIS (Netherlands)

    Kamara, David A; Ryom, Lene; Ross, Michael; Kirk, Ole; Reiss, Peter; Morlat, Philippe; Moranne, Olivier; Fux, Christoph A; Mocroft, Amanda; Sabin, Caroline; Lundgren, Jens D; Smith, Colette J; Schölvinck, Elisabeth H.

    2014-01-01

    BACKGROUND: No consensus exists on how to define abnormally rapid deterioration in renal function (Rapid Progression, RP). We developed an operational definition of RP in HIV-positive persons with baseline estimated glomerular filtration rate (eGFR) >90 ml/min/1.73 m2 (using Cockcroft Gault) in the

  19. Development of a definition for Rapid Progression (RP) of renal function in HIV-positive persons: the D:A:D study

    NARCIS (Netherlands)

    Kamara, David A.; Ryom, Lene; Ross, Michael; Kirk, Ole; Reiss, Peter; Morlat, Philippe; Moranne, Olivier; Fux, Christoph A.; Mocroft, Amanda; Sabin, Caroline; Lundgren, Jens D.; Smith, Colette J.; Powderly, B.; Shortman, N.; Moecklinghoff, C.; Reilly, G.; Franquet, X.; Ryom, L.; Sabin, C. A.; Kamara, D.; Smith, C.; Phillips, A.; Mocroft, A.; Tverland, J.; Mansfeld, M.; Nielsen, J.; Raben, D.; Lundgren, J. D.; Brandt, R. Salbøl; Rickenbach, M.; Fanti, I.; Krum, E.; Hillebregt, M.; Geffard, S.; Sundström, A.; Prins, J. M.; Kuijpers, T. W.; Scherpbier, H. J.; van der Meer, J. T. M.; Wit, F. W. M. N.; Godfried, M. H.; Nellen, F. J. B.; Lange, J. M. A.; Geerlings, S. E.; van Vugt, M.; Pajkrt, D.; Grijsen, M. L.; Wiersinga, W. J.; Goorhuis, A.; Hovius, J. W. R.

    2014-01-01

    No consensus exists on how to define abnormally rapid deterioration in renal function (Rapid Progression, RP). We developed an operational definition of RP in HIV-positive persons with baseline estimated glomerular filtration rate (eGFR) >90 ml/min/1.73 m2 (using Cockcroft Gault) in the Data

  20. Development of a definition for Rapid Progression (RP) of renal function in HIV-positive persons: the D:A:D study

    NARCIS (Netherlands)

    Kamara, D.A.; Ryom, L.; Ross, M.; Kirk, O.; Reiss, P.; Morlat, P.; Moranne, O.; Fux, C.A.; Mocroft, A.; Sabin, C.; Lundgren, J.D.; Smith, C.J.; Koopmans †, P.P.; Keuter, M.; Ven, A.J.A.M. van der; Hofstede, H.J.M. ter; Dofferhoff, A.S.M.; Warris, A.; Crevel, R. van; et al.,

    2014-01-01

    BACKGROUND: No consensus exists on how to define abnormally rapid deterioration in renal function (Rapid Progression, RP). We developed an operational definition of RP in HIV-positive persons with baseline estimated glomerular filtration rate (eGFR) >90 ml/min/1.73 m2 (using Cockcroft Gault) in the

  1. Airway pressure release ventilation and biphasic positive airway pressure: a systematic review of definitional criteria.

    Science.gov (United States)

    Rose, Louise; Hawkins, Martyn

    2008-10-01

    The objective of this study was to identify the definitional criteria for the pressure-limited and time-cycled modes: airway pressure release ventilation (APRV) and biphasic positive airway pressure (BIPAP) available in the published literature. Systematic review. Medline, PubMed, Cochrane, and CINAHL databases (1982-2006) were searched using the following terms: APRV, BIPAP, Bilevel and lung protective strategy, individually and in combination. Two independent reviewers determined the paper eligibility and abstracted data from 50 studies and 18 discussion articles. Of the 50 studies, 39 (78%) described APRV, and 11 (22%) described BIPAP. Various study designs, populations, or outcome measures were investigated. Compared to BIPAP, APRV was described more frequently as extreme inverse inspiratory:expiratory ratio [18/39 (46%) vs. 0/11 (0%), P = 0.004] and used rarely as a noninverse ratio [2/39 (5%) vs. 3/11 (27%), P = 0.06]. One (9%) BIPAP and eight (21%) APRV studies used mild inverse ratio (>1:1 to branding may further add to confusion. Generic naming of modes and consistent definitional parameters may improve consistency of patient response for a given mode and assist with clinical implementation.

  2. Hermitian versus holomorphic complex and quaternionic generalized supersymmetries of the M-theory. A classification

    International Nuclear Information System (INIS)

    Toppan, Francesco

    2004-06-01

    Relying upon the division-algebra classification of Clifford algebras and spinors, a classification of generalized supersymmetries (or, with a slight abuse of language, 'generalized super translations') is provided. In each given space-time the maximal, saturated, generalized supersymmetry, compatible with the division-algebra constraint that can be consistently imposed on spinors and on superalgebra generators, is furnished. Constraining the superalgebra generators in both the complex and the quaternionic cases gives rise to the two classes of constrained hermitian and holomorphic generalized supersymmetries. In the complex case these two classes of generalized supersymmetries can be regarded as complementary. The quaternionic holomorphic supersymmetry only exists in certain space-time dimensions and can admit at most a single bosonic scalar central charge. The results here presented pave the way for a better understanding of the various M algebra-type of structures which can be introduced in different space-time signatures and in association with different division algebras, as well as their mutual relations. In a previous work, e.g., the introduction of a complex holomorphic generalized supersymmetry was shown to be necessary in order to perform the analytic continuation of the standard M-theory to the 11-dimensional Euclidean space. As an application of the present results, it is shown that the above algebra also admits a 12-dimensional, Euclidean, F-algebra presentation. (author)

  3. The Extremism of Two Variable Function Based on the Positive Definite Property

    Institute of Scientific and Technical Information of China (English)

    Lü Bao-xian; LI Xiu-li

    2004-01-01

    In this paper we give out a sufficientand solution of quadratic function's maximum with theory of quadratic form and give out the definition of the positivedefinite property of the following homogeneous polynomials of degree 2n two variables function, based on the definite of localmaximum of two variables function.

  4. Dosimetric comparison of the specific anthropomorphic mannequin (SAM) to 14 anatomical head models using a novel definition for the mobile phone positioning

    International Nuclear Information System (INIS)

    Kainz, Wolfgang; Christ, Andreas; Kellom, Tocher; Seidman, Seth; Nikoloski, Neviana; Beard, Brian; Kuster, Niels

    2005-01-01

    This paper presents new definitions for obtaining reproducible results in numerical phone dosimetry. Numerous numerical dosimetric studies have been published about the exposure of mobile phone users which concluded with conflicting results. However, many of these studies lack reproducibility due to shortcomings in the description of the phone positioning. The new approach was tested by two groups applying two different numerical program packages to compare the specific anthropomorphic mannequin (SAM) to 14 anatomically correct head models. A novel definition for the positioning of mobile phones next to anatomically correct head models is given along with other essential parameters to be reported. The definition is solely based on anatomical characteristics of the head. A simple up-to-date phone model was used to determine the peak spatial specific absorption rate (SAR) of mobile phones in SAM and in the anatomically correct head models. The results were validated by measurements. The study clearly shows that SAM gives a conservative estimate of the exposure in anatomically correct head models for head only tissue. Depending on frequency, phone position and head size the numerically calculated 10 g averaged SAR in the pinna can be up to 2.1 times greater than the peak spatial SAR in SAM. Measurements in small structures, such as the pinna, will significantly increase the uncertainty; therefore SAM was designed for SAR assessment in the head only. Whether SAM will provide a conservative value for the pinna depends on the pinna SAR limit of the safety standard considered

  5. The effects of intraoperative positioning on patients undergoing early definitive care for femoral shaft fractures.

    Science.gov (United States)

    Apostle, K L; Lefaivre, K A; Guy, P; Broekhuyse, H M; Blachut, P A; O'Brien, P J; Meek, R N

    2009-10-01

    To determine if there is a difference in morbidity and mortality in orthopaedic trauma patients with femoral shaft fractures undergoing early definitive care with intramedullary (IM) nails in the supine versus the lateral position. Retrospective cohort study, single centered. One level 1 trauma center. Nine hundred eighty-eight patients representing 1027 femoral shaft fractures treated with IM nails were identified through a prospectively gathered database between 1987 and 2006. Antegrade IM nail insertion with reaming of the femoral canal in either the supine or lateral position. Mortality was the primary outcome. Admission to intensive care unit (ICU) was the secondary outcome measure and a surrogate measure of morbidity. Literature review was performed to identify factors shown to contribute to morbidity and mortality in orthopaedic trauma patients. Intraoperative position in either the supine or lateral position was added to this list. Logistic regression analysis was performed to determine the magnitude and effect of the independent variables on each of the study end points. To determine if a more significant trend toward less favorable outcomes was observed with increasing severity of injury, particularly injuries of the chest and thorax, subgroup analysis was performed for all those with a femur fracture and an Injury Severity Score > or =18 and all those with a femur fracture and an Abbreviated Injury Score chest > or =3. Intraoperative position in either the supine or lateral position was not a significant predictor of mortality or ICU admission for the original cohort or the subgroup of Injury Severity Score > or =18. However, for the subgroup of Abbreviated Injury Score chest > or =3, intraoperative positioning in the lateral position had a statistically significant protective effect against ICU admission (P = 0.044). For polytrauma patients with femoral shaft fractures, surgical stabilization using IM nails inserted with reaming of the femoral canal in

  6. Robust Covariance Estimators Based on Information Divergences and Riemannian Manifold

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Hua

    2018-03-01

    Full Text Available This paper proposes a class of covariance estimators based on information divergences in heterogeneous environments. In particular, the problem of covariance estimation is reformulated on the Riemannian manifold of Hermitian positive-definite (HPD matrices. The means associated with information divergences are derived and used as the estimators. Without resorting to the complete knowledge of the probability distribution of the sample data, the geometry of the Riemannian manifold of HPD matrices is considered in mean estimators. Moreover, the robustness of mean estimators is analyzed using the influence function. Simulation results indicate the robustness and superiority of an adaptive normalized matched filter with our proposed estimators compared with the existing alternatives.

  7. 48 CFR 204.7101 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... OF DEFENSE GENERAL ADMINISTRATIVE MATTERS Uniform Contract Line Item Numbering System 204.7101 Definitions. Accounting classification reference number (ACRN) means any combination of a two position alpha... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Definitions. 204.7101...

  8. Statin intolerance – an attempt at a unified definition. Position paper from an International Lipid Expert Panel

    Science.gov (United States)

    Rizzo, Manfredi; Toth, Peter P.; Farnier, Michel; Davidson, Michael H.; Al-Rasadi, Khalid; Aronow, Wilbert S.; Athyros, Vasilis; Djuric, Dragan M.; Ezhov, Marat V.; Greenfield, Robert S.; Hovingh, G. Kees; Kostner, Karam; Serban, Corina; Lighezan, Daniel; Fras, Zlatko; Moriarty, Patrick M.; Muntner, Paul; Goudev, Assen; Ceska, Richard; Nicholls, Stephen J.; Broncel, Marlena; Nikolic, Dragana; Pella, Daniel; Puri, Raman; Rysz, Jacek; Wong, Nathan D.; Bajnok, Laszlo; Jones, Steven R.; Ray, Kausik K.; Mikhailidis, Dimitri P.

    2015-01-01

    Statins are one of the most commonly prescribed drugs in clinical practice. They are usually well tolerated and effectively prevent cardiovascular events. Most adverse effects associated with statin therapy are muscle-related. The recent statement of the European Atherosclerosis Society (EAS) has focused on statin associated muscle symptoms (SAMS), and avoided the use of the term ‘statin intolerance’. Although muscle syndromes are the most common adverse effects observed after statin therapy, excluding other side effects might underestimate the number of patients with statin intolerance, which might be observed in 10–15% of patients. In clinical practice, statin intolerance limits effective treatment of patients at risk of, or with, cardiovascular disease. Knowledge of the most common adverse effects of statin therapy that might cause statin intolerance and the clear definition of this phenomenon is crucial to effectively treat patients with lipid disorders. Therefore, the aim of this position paper was to suggest a unified definition of statin intolerance, and to complement the recent EAS statement on SAMS, where the pathophysiology, diagnosis and the management were comprehensively presented. PMID:25861286

  9. Building a Definition of Irritability From Academic Definitions and Lay Descriptions.

    Science.gov (United States)

    Barata, Paula C; Holtzman, Susan; Cunningham, Shannon; O'Connor, Brian P; Stewart, Donna E

    2016-04-08

    The current work builds a definition of irritability from both academic definitions and lay perspectives. In Study 1, a quantitative content analysis of academic definitions resulted in eight main content categories (i.e., behaviour, emotion or affect, cognition, physiological, qualifiers, irritant, stability or endurance, and other). In Study 2, a community sample of 39 adults participated in qualitative interviews. A deductive thematic analysis resulted in two main themes. The first main theme dealt with how participants positioned irritability in relation to other negative states. The second dealt with how participants constructed irritability as both a loss of control and as an experience that should be controlled. The discussion integrates the findings of both studies and provides a concise, but comprehensive definition.

  10. Life is hard: countering definitional pessimism concerning the definition of life

    Science.gov (United States)

    Smith, Kelly C.

    2016-10-01

    Cleland and Chyba published a classic piece in 2002 that began a movement I call definitional pessimism, where it is argued that there is no point in attempting anything like a general definition of life. This paper offers a critical response to the pessimist position in general and the influential arguments offered by Cleland and her collaborators in particular. One such argument is that all definitions of life fall short of an ideal in which necessary and sufficient conditions produce unambiguous categorizations that dispose of all counterexamples. But this concept of definition is controversial within philosophy; a fact that greatly diminishes the force of the admonition that biologists should conform to such an ideal. Moreover, biology may well be fundamentally different from logic and the physical sciences from which this ideal is drawn, to the point where definitional conformity misrepresents biological reality. Another idea often pushed is that the prospects for definitional success concerning life are on a par with medieval alchemy's attempts to define matter - that is, doomed to fail for lack of a unifying scientific theory. But this comparison to alchemy is both historically inaccurate and unfair. Planetary science before the discovery of the first exoplanets offers a much better analogy, with much more optimistic conclusions. The pessimists also make much of the desirability of using microbes as models for any universal concept of life, from which they conclude that certain types of 'Darwinian' evolutionary definitions are inadequate. But this argument posits an unrealistic ideal, as no account of life can both be universal and do justice to the sorts of precise causal mechanisms microbes exemplify. The character of biology and the demand for universality in definitions of life thus probably accords better with functional rather than structural categories. The bottom line is that there is simply no viable alternative, either pragmatically or

  11. 5 CFR 531.403 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Definitions. 531.403 Section 531.403 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY UNDER THE GENERAL SCHEDULE... not have a definite time limitation of one year or less. “Permanent position” includes a position to...

  12. Multiple Meixner polynomials and non-Hermitian oscillator Hamiltonians

    OpenAIRE

    Ndayiragije, François; Van Assche, Walter

    2013-01-01

    Multiple Meixner polynomials are polynomials in one variable which satisfy orthogonality relations with respect to $r>1$ different negative binomial distributions (Pascal distributions). There are two kinds of multiple Meixner polynomials, depending on the selection of the parameters in the negative binomial distribution. We recall their definition and some formulas and give generating functions and explicit expressions for the coefficients in the nearest neighbor recurrence relation. Followi...

  13. Simple Closed-Form Expression for Penning Reaction Rate Coefficients for Cold Molecular Collisions by Non-Hermitian Time-Independent Adiabatic Scattering Theory.

    Science.gov (United States)

    Pawlak, Mariusz; Ben-Asher, Anael; Moiseyev, Nimrod

    2018-01-09

    We present a simple expression and its derivation for reaction rate coefficients for cold anisotropic collision experiments based on adiabatic variational theory and time-independent non-Hermitian scattering theory. We demonstrate that only the eigenenergies of the resulting one-dimensional Schrödinger equation for different complex adiabats are required. The expression is applied to calculate the Penning ionization rate coefficients of an excited metastable helium atom with molecular hydrogen in an energy range spanning from hundreds of kelvins down to the millikelvin regime. Except for trivial quantities like the masses of the nuclei and the bond length of the diatomic molecule participating in the collision, one needs as input data only the complex potential energy surface (CPES). In calculations, we used recently obtained ab initio CPES by D. Bhattacharya et al. ( J. Chem. Theory Comput. 2017 , 13 , 1682 - 1690 ) without fitting parameters. The results show good accord with current measurements ( Nat. Phys. 2017 , 13 , 35 - 38 ).

  14. Positive predictive value of a case definition for diabetes mellitus using automated administrative health data in children and youth exposed to antipsychotic drugs or control medications: a Tennessee Medicaid study.

    Science.gov (United States)

    Bobo, William V; Cooper, William O; Stein, C Michael; Olfson, Mark; Mounsey, Jackie; Daugherty, James; Ray, Wayne A

    2012-08-24

    We developed and validated an automated database case definition for diabetes in children and youth to facilitate pharmacoepidemiologic investigations of medications and the risk of diabetes. The present study was part of an in-progress retrospective cohort study of antipsychotics and diabetes in Tennessee Medicaid enrollees aged 6-24 years. Diabetes was identified from diabetes-related medical care encounters: hospitalizations, outpatient visits, and filled prescriptions. The definition required either a primary inpatient diagnosis or at least two other encounters of different types, most commonly an outpatient diagnosis with a prescription. Type 1 diabetes was defined by insulin prescriptions with at most one oral hypoglycemic prescription; other cases were considered type 2 diabetes. The definition was validated for cohort members in the 15 county region geographically proximate to the investigators. Medical records were reviewed and adjudicated for cases that met the automated database definition as well as for a sample of persons with other diabetes-related medical care encounters. The study included 64 cases that met the automated database definition. Records were adjudicated for 46 (71.9%), of which 41 (89.1%) met clinical criteria for newly diagnosed diabetes. The positive predictive value for type 1 diabetes was 80.0%. For type 2 and unspecified diabetes combined, the positive predictive value was 83.9%. The estimated sensitivity of the definition, based on adjudication for a sample of 30 cases not meeting the automated database definition, was 64.8%. These results suggest that the automated database case definition for diabetes may be useful for pharmacoepidemiologic studies of medications and diabetes.

  15. THE PRACTICAL ANALYSIS OF FINITE ELEMENTS METHOD ERRORS

    Directory of Open Access Journals (Sweden)

    Natalia Bakhova

    2011-03-01

    Full Text Available Abstract. The most important in the practical plan questions of reliable estimations of finite elementsmethod errors are considered. Definition rules of necessary calculations accuracy are developed. Methodsand ways of the calculations allowing receiving at economical expenditures of computing work the best finalresults are offered.Keywords: error, given the accuracy, finite element method, lagrangian and hermitian elements.

  16. A positive semi-definite action in a Kaluza-Klein theory with compactification onto time-like extra dimensions

    International Nuclear Information System (INIS)

    Pollock, M.D.

    1986-01-01

    We consider the (4+N)-dimensional theory whose Lagrangian function is Lsub(4+N)=√-g-circumflex α R-circumflex 2 , where R-circumflex is the Ricci scalar and α is a positive constant. The metric is g-circumflexsub(AB)= diag(gsub(ab), phi -1 g-barsub(mn)). Dimensional reduction leads to an effective four-dimensional Lagrangian of induced-gravity type. The positive semi-definiteness of L avoids the difficulties, pointed out recently by Horowitz and by Rubakov, which can arise in quantum cosmology when the (Euclidean) action becomes negative. The compactification is onto a time-like internal space g-barsub(mn), as suggested by Aref'eva and Volovich, giving a four-dimensional de Sitter space-time with phi=constant, which however is classically unstable on a time scale approx. H -1 . Decrease of the radius phisup(-1/2) of the internal space is ultimately halted by quantum effects, via some V(phi), and L 4 then includes the usual Hilbert term and a cosmological constant. (author)

  17. Robust domain decomposition preconditioners for abstract symmetric positive definite bilinear forms

    KAUST Repository

    Efendiev, Yalchin

    2012-02-22

    An abstract framework for constructing stable decompositions of the spaces corresponding to general symmetric positive definite problems into "local" subspaces and a global "coarse" space is developed. Particular applications of this abstract framework include practically important problems in porous media applications such as: the scalar elliptic (pressure) equation and the stream function formulation of its mixed form, Stokes\\' and Brinkman\\'s equations. The constant in the corresponding abstract energy estimate is shown to be robust with respect to mesh parameters as well as the contrast, which is defined as the ratio of high and low values of the conductivity (or permeability). The derived stable decomposition allows to construct additive overlapping Schwarz iterative methods with condition numbers uniformly bounded with respect to the contrast and mesh parameters. The coarse spaces are obtained by patching together the eigenfunctions corresponding to the smallest eigenvalues of certain local problems. A detailed analysis of the abstract setting is provided. The proposed decomposition builds on a method of Galvis and Efendiev [Multiscale Model. Simul. 8 (2010) 1461-1483] developed for second order scalar elliptic problems with high contrast. Applications to the finite element discretizations of the second order elliptic problem in Galerkin and mixed formulation, the Stokes equations, and Brinkman\\'s problem are presented. A number of numerical experiments for these problems in two spatial dimensions are provided. © EDP Sciences, SMAI, 2012.

  18. Positive predictive value of a case definition for diabetes mellitus using automated administrative health data in children and youth exposed to antipsychotic drugs or control medications: a Tennessee Medicaid study

    Directory of Open Access Journals (Sweden)

    Bobo William V

    2012-08-01

    Full Text Available Abstract Background We developed and validated an automated database case definition for diabetes in children and youth to facilitate pharmacoepidemiologic investigations of medications and the risk of diabetes. Methods The present study was part of an in-progress retrospective cohort study of antipsychotics and diabetes in Tennessee Medicaid enrollees aged 6–24 years. Diabetes was identified from diabetes-related medical care encounters: hospitalizations, outpatient visits, and filled prescriptions. The definition required either a primary inpatient diagnosis or at least two other encounters of different types, most commonly an outpatient diagnosis with a prescription. Type 1 diabetes was defined by insulin prescriptions with at most one oral hypoglycemic prescription; other cases were considered type 2 diabetes. The definition was validated for cohort members in the 15 county region geographically proximate to the investigators. Medical records were reviewed and adjudicated for cases that met the automated database definition as well as for a sample of persons with other diabetes-related medical care encounters. Results The study included 64 cases that met the automated database definition. Records were adjudicated for 46 (71.9%, of which 41 (89.1% met clinical criteria for newly diagnosed diabetes. The positive predictive value for type 1 diabetes was 80.0%. For type 2 and unspecified diabetes combined, the positive predictive value was 83.9%. The estimated sensitivity of the definition, based on adjudication for a sample of 30 cases not meeting the automated database definition, was 64.8%. Conclusion These results suggest that the automated database case definition for diabetes may be useful for pharmacoepidemiologic studies of medications and diabetes.

  19. Positive predictive value of a case definition for diabetes mellitus using automated administrative health data in children and youth exposed to antipsychotic drugs or control medications: a Tennessee Medicaid study

    Science.gov (United States)

    2012-01-01

    Background We developed and validated an automated database case definition for diabetes in children and youth to facilitate pharmacoepidemiologic investigations of medications and the risk of diabetes. Methods The present study was part of an in-progress retrospective cohort study of antipsychotics and diabetes in Tennessee Medicaid enrollees aged 6–24 years. Diabetes was identified from diabetes-related medical care encounters: hospitalizations, outpatient visits, and filled prescriptions. The definition required either a primary inpatient diagnosis or at least two other encounters of different types, most commonly an outpatient diagnosis with a prescription. Type 1 diabetes was defined by insulin prescriptions with at most one oral hypoglycemic prescription; other cases were considered type 2 diabetes. The definition was validated for cohort members in the 15 county region geographically proximate to the investigators. Medical records were reviewed and adjudicated for cases that met the automated database definition as well as for a sample of persons with other diabetes-related medical care encounters. Results The study included 64 cases that met the automated database definition. Records were adjudicated for 46 (71.9%), of which 41 (89.1%) met clinical criteria for newly diagnosed diabetes. The positive predictive value for type 1 diabetes was 80.0%. For type 2 and unspecified diabetes combined, the positive predictive value was 83.9%. The estimated sensitivity of the definition, based on adjudication for a sample of 30 cases not meeting the automated database definition, was 64.8%. Conclusion These results suggest that the automated database case definition for diabetes may be useful for pharmacoepidemiologic studies of medications and diabetes. PMID:22920280

  20. European Position Paper on Rhinosinusitis and Nasal Polyps 2012

    NARCIS (Netherlands)

    Fokkens, Wytske J.; Lund, Valerie J.; Mullol, Joachim; Bachert, Claus; Alobid, Isam; Baroody, Fuad; Cohen, Noam; Cervin, Anders; Douglas, Richard; Gevaert, Philippe; Georgalas, Christos; Goossens, Herman; Harvey, Richard; Hellings, Peter; Hopkins, Claire; Jones, Nick; Joos, Guy; Kalogjera, Livije; Kern, Bob; Kowalski, Marek; Price, David; Riechelmann, Herbert; Schlosser, Rodney; Senior, Brent; Thomas, Mike; Toskala, Elina; Voegels, Richard; Wang, De Yun; Wormald, Peter John

    2012-01-01

    The European Position Paper on Rhinosinusitis and Nasal Polyps 2012 is the update of similar evidence based position papers published in 2005 and 2007.The document contains chapters on definitions and classification, we now also proposed definitions for difficult to treat rhinosinusitis, control of

  1. 5 CFR 351.203 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... for a position covered by a wage-board or similar wage-determining procedure, such as provided in the definition of representative rate for Federal Wage System positions in 5 CFR 532.401 of this chapter; (3) For... low priority program or to a vacant position. [51 FR 319, Jan. 3, 1986, as amended at 58 FR 65533, Dec...

  2. Incidence and risk factors of AIDS-defining cancers in a cohort of HIV-positive adults: Importance of the definition of incident cases.

    Science.gov (United States)

    Suárez-García, Inés; Jarrín, Inmaculada; Iribarren, José Antonio; López-Cortés, Luis Fernando; Lacruz-Rodrigo, José; Masiá, Mar; Gómez-Sirvent, Juan Luis; Hernández-Quero, José; Vidal, Francesc; Alejos-Ferreras, Belén; Moreno, Santiago; Del Amo, Julia

    2013-05-01

    The aim of this study was to investigate the incidence and risk factors for the development of AIDS-defining cancers (ADCs); and to investigate the effect of making different assumptions on the definition of incident cases. A multicentre cohort study was designed. Poisson regression was used to assess incidence and risk factors. To account for misclassification, incident cases were defined using lag-times of 0, 14 and 30 days after enrolment. A total of 6393 HIV-positive subjects were included in the study. The incidences of ADCs changed as the lag periods were varied from 0 to 30 days. Different risk factors emerged as the definition of incident cases was changed. For a lag time of 0, the risk of Kaposi sarcoma [KS] and non-Hodgkin lymphoma [NHL] increased at CD4 counts sex with men had a higher risk of KS. KS and NHL were not associated with viral load, gender, or hepatitis B or C. The results were similar for a lag-time of 14 and 30 days; however, hepatitis C was significantly associated with NHL. This analysis shows the importance of the definition of incident cases in cohort studies. Alternative definitions gave different incidence estimates, and may have implications for the analysis of risk factors. Copyright © 2011 Elsevier España, S.L. All rights reserved.

  3. 41 CFR 60-742.8 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... controversial topics under the ADA on which there is not yet definitive guidance setting forth EEOC's position... HOLDING GOVERNMENT CONTRACTS OR SUBCONTRACTS § 60-742.8 Definitions. As used in this part, the term: ADA... the Rehabilitation Act of 1973, that go beyond the nondiscrimination requirements imposed by the ADA...

  4. Supermanifolds and Berezin's new integral

    International Nuclear Information System (INIS)

    Ne'eman, Y.

    1984-01-01

    Berezin's new integral over a supermanifold is introduced and some of its applications are discussed. Generalized superdifferential exterior forms are outlined. The application of the concept of complementary forms to the integration over a sub-supermanifold is discussed. Commutative differentials are treated as plain commuting variables. The necessary definitions for a scalar product, possibly hermitian, are given. Characteristic classes are discussed

  5. A computer case definition for sudden cardiac death.

    Science.gov (United States)

    Chung, Cecilia P; Murray, Katherine T; Stein, C Michael; Hall, Kathi; Ray, Wayne A

    2010-06-01

    To facilitate studies of medications and sudden cardiac death, we developed and validated a computer case definition for these deaths. The study of community dwelling Tennessee Medicaid enrollees 30-74 years of age utilized a linked database with Medicaid inpatient/outpatient files, state death certificate files, and a state 'all-payers' hospital discharge file. The computerized case definition was developed from a retrospective cohort study of sudden cardiac deaths occurring between 1990 and 1993. Medical records for 926 potential cases had been adjudicated for this study to determine if they met the clinical definition for sudden cardiac death occurring in the community and were likely to be due to ventricular tachyarrhythmias. The computerized case definition included deaths with (1) no evidence of a terminal hospital admission/nursing home stay in any of the data sources; (2) an underlying cause of death code consistent with sudden cardiac death; and (3) no terminal procedures inconsistent with unresuscitated cardiac arrest. This definition was validated in an independent sample of 174 adjudicated deaths occurring between 1994 and 2005. The positive predictive value of the computer case definition was 86.0% in the development sample and 86.8% in the validation sample. The positive predictive value did not vary materially for deaths coded according to the ICO-9 (1994-1998, positive predictive value = 85.1%) or ICD-10 (1999-2005, 87.4%) systems. A computerized Medicaid database, linked with death certificate files and a state hospital discharge database, can be used for a computer case definition of sudden cardiac death. Copyright (c) 2009 John Wiley & Sons, Ltd.

  6. The Requirement of a Positive Definite Covariance Matrix of Security Returns for Mean-Variance Portfolio Analysis: A Pedagogic Illustration

    Directory of Open Access Journals (Sweden)

    Clarence C. Y. Kwan

    2010-07-01

    Full Text Available This study considers, from a pedagogic perspective, a crucial requirement for the covariance matrix of security returns in mean-variance portfolio analysis. Although the requirement that the covariance matrix be positive definite is fundamental in modern finance, it has not received any attention in standard investment textbooks. Being unaware of the requirement could cause confusion for students over some strange portfolio results that are based on seemingly reasonable input parameters. This study considers the requirement both informally and analytically. Electronic spreadsheet tools for constrained optimization and basic matrix operations are utilized to illustrate the various concepts involved.

  7. [Radiotherapy in node-positive prostate cancer].

    Science.gov (United States)

    Bottke, D; Bartkowiak, D; Bolenz, C; Wiegel, T

    2016-03-01

    There are numerous randomized trials to guide the management of patients with localized (and metastatic) prostate cancer, but only a few (mostly retrospective) studies have specifically addressed node-positive patients. Therefore, there is uncertainty regarding optimal treatment in this situation. Current guidelines recommend long-term androgen deprivation therapy (ADT) alone or radiotherapy plus long-term ADT as treatment options. This overview summarizes the existing literature on the use of radiotherapy for node-positive prostate cancer as definitive treatment and as adjuvant or salvage therapy after radical prostatectomy. In this context, we also discuss several PET tracers in the imaging evaluation of patients with biochemical recurrence of prostate cancer after radical prostatectomy. As for definitive treatment, retrospective studies suggest that ADT plus radiotherapy improves overall survival compared with ADT alone. These studies also consistently demonstrated that many patients with node-positive prostate cancer can achieve long-term survival - and are likely curable - with aggressive therapy. The beneficial impact of adjuvant radiotherapy on survival in patients with pN1 prostate cancer seems to be highly influenced by tumor characteristics. Men with ≤ 2 positive lymph nodes in the presence of intermediate- to high-grade disease, or positive margins, and those with 3 or 4 positive lymph nodes are the ideal candidates for adjuvant radiotherapy (plus long-term ADT) after surgery. There is a need for randomized trials to further examine the potential role of radiotherapy as either definitive or adjuvant treatment, for patients with node-positive prostate cancer.

  8. On Complex Random Variables

    Directory of Open Access Journals (Sweden)

    Anwer Khurshid

    2012-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE In this paper, it is shown that a complex multivariate random variable  is a complex multivariate normal random variable of dimensionality if and only if all nondegenerate complex linear combinations of  have a complex univariate normal distribution. The characteristic function of  has been derived, and simpler forms of some theorems have been given using this characterization theorem without assuming that the variance-covariance matrix of the vector  is Hermitian positive definite. Marginal distributions of  have been given. In addition, a complex multivariate t-distribution has been defined and the density derived. A characterization of the complex multivariate t-distribution is given. A few possible uses of this distribution have been suggested.

  9. Restricted numerical range: A versatile tool in the theory of quantum information

    Science.gov (United States)

    Gawron, Piotr; Puchała, Zbigniew; Miszczak, Jarosław Adam; Skowronek, Łukasz; Życzkowski, Karol

    2010-10-01

    Numerical range of a Hermitian operator X is defined as the set of all possible expectation values of this observable among a normalized quantum state. We analyze a modification of this definition in which the expectation value is taken among a certain subset of the set of all quantum states. One considers, for instance, the set of real states, the set of product states, separable states, or the set of maximally entangled states. We show exemplary applications of these algebraic tools in the theory of quantum information: analysis of k-positive maps and entanglement witnesses, as well as study of the minimal output entropy of a quantum channel. Product numerical range of a unitary operator is used to solve the problem of local distinguishability of a family of two unitary gates.

  10. Delta-function potential with a complex coupling

    International Nuclear Information System (INIS)

    Mostafazadeh, Ali

    2006-01-01

    We explore the Hamiltonian operator H = -d 2 /dx 2 + zδ(x), where x element of R, δ(x) is the Dirac delta function and z is an arbitrary complex coupling constant. For a purely imaginary z, H has a spectral singularity at E = -z 2 /4 element of R + . For Re(z) 2 /4. For the case that Re(z) > 0, H has a real, positive, continuous spectrum that is free from spectral singularities. For this latter case, we construct an associated biorthonormal system and use it to perform a perturbative calculation of a positive-definite inner product that renders H self-adjoint. This allows us to address the intriguing question of the nonlocal aspects of the equivalent Hermitian Hamiltonian for the system. In particular, we compute the energy expectation values for various Gaussian wave packets to show that the non-Hermiticity effect diminishes rapidly outside an effective interaction region

  11. Solitonic dynamics and excitations of the nonlinear Schrödinger equation with third-order dispersion in non-Hermitian PT-symmetric potentials.

    Science.gov (United States)

    Chen, Yong; Yan, Zhenya

    2016-03-22

    Solitons are of the important significant in many fields of nonlinear science such as nonlinear optics, Bose-Einstein condensates, plamas physics, biology, fluid mechanics, and etc. The stable solitons have been captured not only theoretically and experimentally in both linear and nonlinear Schrödinger (NLS) equations in the presence of non-Hermitian potentials since the concept of the parity-time -symmetry was introduced in 1998. In this paper, we present novel bright solitons of the NLS equation with third-order dispersion in some complex -symmetric potentials (e.g., physically relevant -symmetric Scarff-II-like and harmonic-Gaussian potentials). We find stable nonlinear modes even if the respective linear -symmetric phases are broken. Moreover, we also use the adiabatic changes of the control parameters to excite the initial modes related to exact solitons to reach stable nonlinear modes. The elastic interactions of two solitons are exhibited in the third-order NLS equation with -symmetric potentials. Our results predict the dynamical phenomena of soliton equations in the presence of third-order dispersion and -symmetric potentials arising in nonlinear fiber optics and other physically relevant fields.

  12. Quantum measurement with a positive operator-valued measure

    International Nuclear Information System (INIS)

    Brandt, Howard E

    2003-01-01

    In the quantum theory of measurement, the positive operator-valued measure (POVM) is an important concept, and its implementation can be useful. A POVM consists of a set of non-negative quantum-mechanical Hermitian operators that add up to the identity. The probability that a quantum system is in a particular state is given by the expectation value of the POVM operator corresponding to that state. Following a brief review of the mathematics and mention of the history of POVMs in quantum theory, a particular implementation of a POVM for use in the measurement of nonorthogonal photon polarization states is reviewed. The implementation consists simply of a Wollaston prism, a mirror, two beam splitters, a polarization rotator and three phototubes arranged in an interferometric configuration, and it is shown analytically that the device faithfully represents the POVM. Based on Neumark's extension theorem, the two-dimensional Hilbert space of the POVM implementation can be embedded in the three-dimensional Hilbert space of an ordinary projective-valued measure. Also, analytical expressions are given for the maximum Renyi information loss from the device to a disturbing probe, and for the error and inconclusive rates induced by the probe. Various aspects of the problem of probe optimization are elaborated

  13. FLIC-overlap fermions and topology

    International Nuclear Information System (INIS)

    Kamleh, W.; Kusterer, D.J.; Leinweber, D.B.; Williams, A.G.

    2003-01-01

    APE smearing the links in the irrelevant operators of clover fermions (Fat-Link Irrelevant Clover (FLIC) fermions) provides significant improvement in the condition number of the Hermitian-Dirac operator and gives rise to a factor of two savings in computing the overlap operator. This report investigates the effects of using a highly-improved definition of the lattice field-strength tensor F μν in the fermion action, made possible through the use of APE-smeared fat links in the construction of the irrelevant operators. Spurious double-zero crossings in the spectral flow of the Hermitian-Wilson Dirac operator associated with lattice artifacts at the scale of the lattice spacing are removed with FLIC fermions composed with an O(α 4 )-improved lattice field strength tensor. Hence, FLIC-Overlap fermions provide an additional benefit to the overlap formalism: a correct realization of topology in the fermion sector on the lattice

  14. Evaluation of the WHO clinical case definition for pediatric HIV infection in Bloemfontein, South Africa.

    Science.gov (United States)

    van Gend, Christine L; Haadsma, Maaike L; Sauer, Pieter J J; Schoeman, Cornelius J

    2003-06-01

    The WHO clinical case definition for pediatric HIV infection has been designed to be used in countries where diagnostic laboratory resources are limited. We evaluated the WHO case definition to determine whether it is a useful instrument to discriminate between HIV-positive and HIV-negative children. In addition, clinical features not included in this case definition were recorded. We recorded clinical data from 300 consecutively admitted children in a state hospital in Bloemfontein, South Africa, and tested these children for HIV infection. A total of 222 children were included in the study; 69 children (31.1 per cent) were HIV positive. The sensitivity of the WHO case definition in this study was 14.5 per cent, the specificity was 98.6 per cent. Apart from weight loss and generalized dermatitis, the signs of the WHO case definition were significantly more often seen in HIV-positive than in HIV-negative children. Of the clinical signs not included in the WHO case definition, marasmus and hepatosplenomegaly especially occurred more frequently in HIV-positive children. Based on these findings we composed a new case definition consisting of four signs: marasmus, hepatosplenomegaly, oropharyngeal candidiasis, and generalized lymphadenopathy. HIV infection is suspected in a child presenting with at least two of these four signs. The sensitivity of this case definition was 63.2 per cent, the specificity was 96.0 per cent. We conclude that in this study the WHO case definition was not a useful instrument to discriminate between HIV-positive and HIV-negative children, mainly because its sensitivity was strikingly low. The simplified case definition we propose, proved to be more sensitive than the WHO case definition (63.2 vs. 14.5 per cent), whilst its specificity remained high.

  15. Tacit definitions of informal caregiving.

    Science.gov (United States)

    Wrubel, J; Richards, T A; Folkman, S; Acree, M C

    2001-01-01

    This study describes three tacit definitions of informal caregiving and explores the extent to which differences in these tacit definitions explain variation in caregivers' negative mood over time. There is a growing need to understand the sources of stress and gratification for informal caregivers. Tacit definitions of informal caregiving refer to caregivers' understanding of what caregiving entails. These definitions are tacit because they arise from caregivers' taken-for-granted understanding rather than formally articulated positions concerning caregiving. A random sample of 60 men, all of whom were caregiving partners of men with acquired immunodeficiency syndrome (AIDS), was drawn from a larger cohort of 253 participants in the University of California San Francisco (UCSF) Coping Project (1990-1997). The caregivers were assessed bimonthly for 2 years with procedures that included a semi-structured interview focusing on a recent stressful event involving caregiving, and quantitative measures of well-being. Interpretive phenomenological case studies of the narrative accounts of the 60 caregivers produced three tacit definitions of caregiving - engagement, conflict and distance. These three tacit definitions were distinguished by differences in learning about caregiving, involvement in health care decisions, caregiving activities and reported sources of stress. The three groups differed on measures of dyadic adjustment, depression, anger and anxiety. Better understanding of caregivers' tacit definitions can facilitate and enhance effective support and interventions for caregivers.

  16. Positive-definite matrix processes of finite variation

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Stelzer, Robert

    2007-01-01

    Processes of finite variation, which take values in the positive semidefinite matrices and are representable as the sum of an integral with respect to time and one with respect to an extended Poisson random measure, are considered. For such processes we derive conditions for the square root (and ...

  17. Positive-Definite Matrix Processes of Finite Variation

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Stelzer, Robert

    Processes of finite variation, which take values in the positive semidefinite matrices and are representable as the sum of an integral with respect to time and one with respect to an extended Poisson random measure, are considered. For such processes we derive conditions for the square root (and ...

  18. Matched Cohort Analysis of Outcomes of Definitive Radiotherapy for Prostate Cancer in Human Immunodeficiency Virus-Positive Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Shannon, E-mail: shannonkahn@yahoo.com [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA (United States); Jani, Ashesh; Edelman, Scott; Rossi, Peter; Godette, Karen; Landry, Jerome; Anderson, Cynthia [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA (United States); Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA (United States)

    2012-05-01

    Purpose: To compare the biochemical outcome and toxicity scores of men with human immunodeficiency virus (HIV) and prostate cancer with a matched control population with negative or unknown HIV status when treated with external-beam radiotherapy (EBRT). Methods and Materials: A single-institution database of men with prostate cancer treated with EBRT from 1999 to 2009 was reviewed. Thirteen men with HIV were identified and matched to 2 control patients according to age, race, T stage, prostate-specific antigen level, Gleason score, RT dose, intensity-modulated RT vs. three-dimensional conformal RT, and whole-pelvis vs. prostate-only RT, for a total of 39 cases. The median follow-up time was 39 months (range, 3-110 months). Results: The 4-year biochemical failure (BF)-free survival rate was 87% in the HIV-positive group vs. 89% in the controls (p = 0.94). Pre- and post-RT viral loads were found to be predictive of BF (p = 0.04 and p = 0.04, respectively). No men with HIV died, whereas 2 in the control group died of causes unrelated to prostate cancer. Acute and chronic genitourinary and gastrointestinal toxicity were less in the HIV-positive patients than in controls (p < 0.001, p < 0.001, p = 0.003, and p < 0.001, respectively). The HIV-positive men experienced an average decline in CD4 count of 193 cells/mm{sup 3}. Conclusions: Our findings suggest that men with HIV treated with EBRT have a similar risk of BF; however, high viral loads may contribute to an increased risk. This analysis supports that HIV-positive men with prostate cancer can be treated with definitive EBRT with similar disease control and toxicity outcomes as in the general population.

  19. Matched Cohort Analysis of Outcomes of Definitive Radiotherapy for Prostate Cancer in Human Immunodeficiency Virus-Positive Patients

    International Nuclear Information System (INIS)

    Kahn, Shannon; Jani, Ashesh; Edelman, Scott; Rossi, Peter; Godette, Karen; Landry, Jerome; Anderson, Cynthia

    2012-01-01

    Purpose: To compare the biochemical outcome and toxicity scores of men with human immunodeficiency virus (HIV) and prostate cancer with a matched control population with negative or unknown HIV status when treated with external-beam radiotherapy (EBRT). Methods and Materials: A single-institution database of men with prostate cancer treated with EBRT from 1999 to 2009 was reviewed. Thirteen men with HIV were identified and matched to 2 control patients according to age, race, T stage, prostate-specific antigen level, Gleason score, RT dose, intensity-modulated RT vs. three-dimensional conformal RT, and whole-pelvis vs. prostate-only RT, for a total of 39 cases. The median follow-up time was 39 months (range, 3–110 months). Results: The 4-year biochemical failure (BF)-free survival rate was 87% in the HIV-positive group vs. 89% in the controls (p = 0.94). Pre- and post-RT viral loads were found to be predictive of BF (p = 0.04 and p = 0.04, respectively). No men with HIV died, whereas 2 in the control group died of causes unrelated to prostate cancer. Acute and chronic genitourinary and gastrointestinal toxicity were less in the HIV-positive patients than in controls (p 3 . Conclusions: Our findings suggest that men with HIV treated with EBRT have a similar risk of BF; however, high viral loads may contribute to an increased risk. This analysis supports that HIV-positive men with prostate cancer can be treated with definitive EBRT with similar disease control and toxicity outcomes as in the general population.

  20. Workaholism as positive social deviance

    OpenAIRE

    Belousov, Konstantin

    2014-01-01

    The article justifies a potential research of workaholism as a social phenomenon within the positive deviance approach. In this paper, the authors provide definitions of positive deviance by foreign and Russian scholars as well as analyse how such behaviors depart from the norms of a referent group and adduce a number of studies positively assessing the concept. Finally, the authors conclude that workaholism can be regarded as a supraconformal behavior that can boost economic, cultural and sc...

  1. Statin intolerance - a question of definition.

    Science.gov (United States)

    Algharably, Engi Abdel-Hady; Filler, Iris; Rosenfeld, Stephanie; Grabowski, Katja; Kreutz, Reinhold

    2017-01-01

    Statin therapy is the backbone of pharmacologic therapy for low-density lipoproteins cholesterol lowering and plays a pivotal role in cardiovascular disease prevention. Statin intolerance is understood as the inability to continue using a statin to reduce individual cardiovascular risk sufficiently, due to the development of symptoms or laboratory abnormalities attributable to the initiation or dose escalation of a statin. Muscle symptoms are the most common side effects observed. Areas covered: The main aim of this article is to present a review on published definitions of statin intolerance. In addition, a brief review on clinical aspects and risk factors of statin intolerance is provided and features for a common definition for statin intolerance are suggested. Expert opinion: A definition of statin intolerance by major drug regulatory agencies is not available. In clinical studies, different definitions are chosen and results are not comparable; different medical associations do not agree on one common definition. There is an unmet need to establish a common definition of statin intolerance to ensure an appropriate clinical use of this important drug class. Further work is required to develop a consensus definition on statin intolerance that could have significant positive impact on both research and clinical management.

  2. Lung recruitability is better estimated according to the Berlin definition of acute respiratory distress syndrome at standard 5 cm H2O rather than higher positive end-expiratory pressure: a retrospective cohort study.

    Science.gov (United States)

    Caironi, Pietro; Carlesso, Eleonora; Cressoni, Massimo; Chiumello, Davide; Moerer, Onner; Chiurazzi, Chiara; Brioni, Matteo; Bottino, Nicola; Lazzerini, Marco; Bugedo, Guillermo; Quintel, Michael; Ranieri, V Marco; Gattinoni, Luciano

    2015-04-01

    The Berlin definition of acute respiratory distress syndrome has introduced three classes of severity according to PaO2/FIO2 thresholds. The level of positive end-expiratory pressure applied may greatly affect PaO2/FIO2, thereby masking acute respiratory distress syndrome severity, which should reflect the underlying lung injury (lung edema and recruitability). We hypothesized that the assessment of acute respiratory distress syndrome severity at standardized low positive end-expiratory pressure may improve the association between the underlying lung injury, as detected by CT, and PaO2/FIO2-derived severity. Retrospective analysis. Four university hospitals (Italy, Germany, and Chile). One hundred forty-eight patients with acute lung injury or acute respiratory distress syndrome according to the American-European Consensus Conference criteria. Patients underwent a three-step ventilator protocol (at clinical, 5 cm H2O, or 15 cm H2O positive end-expiratory pressure). Whole-lung CT scans were obtained at 5 and 45 cm H2O airway pressure. Nine patients did not fulfill acute respiratory distress syndrome criteria of the novel Berlin definition. Patients were then classified according to PaO2/FIO2 assessed at clinical, 5 cm H2O, or 15 cm H2O positive end-expiratory pressure. At clinical positive end-expiratory pressure (11±3 cm H2O), patients with severe acute respiratory distress syndrome had a greater lung tissue weight and recruitability than patients with mild or moderate acute respiratory distress syndrome (pBerlin definition of acute respiratory distress syndrome assessed at 5 cm H2O allows a better evaluation of lung recruitability and edema than at higher positive end-expiratory pressure clinically set.

  3. Definitive radiotherapy for head-and-neck cancer with radiographically positive retropharyngeal nodes: Incomplete radiographic response does not necessarily indicate failure

    International Nuclear Information System (INIS)

    Liauw, Stanley L.; Mancuso, Anthony A.; Morris, Christopher G. M.S.; Amdur, Robert J.; Mendenhall, William M.

    2006-01-01

    Purpose: Our aim was to report the control rate of radiographically positive retropharyngeal (RP) nodes with radiation therapy (RT) and to correlate posttreatment imaging with clinical outcome. Methods and Materials: Sixteen patients treated with definitive RT for head-and-neck cancer had radiographically positive RP nodes (size >1 cm in largest axial dimension, or presence of focal enhancement, lucency, or calcification), and both pre-RT and post-RT image sets available for review. An additional 21 patients with unconfirmed radiographically positive RP nodes had post-RT imaging, which consisted of computed tomography (CT) at a median of 4 weeks after completing RT. Patients with positive post-RT RP nodes underwent observation with serial imaging. Results: Of 16 patients with pre-RT and post-RT images available for review, 9 (56%) had a radiographic complete response, and of 21 patients with unconfirmed positive RP nodes with post-RT images available for review, 14 (67%) had a radiographic complete response. In all, 14 patients with incomplete response on post-RT imaging experienced control of their disease with no further therapy, and no RP node or neck failures were noted during a median follow-up of 2.8 years. Six patients with positive post-RT RP nodes had serial imaging available for review, and none demonstrated radiographic progression of disease. Conclusions: Radiographic response at 4 weeks may not accurately reflect long-term locoregional control, as RP nodes may continue to resolve over time. The highest index of suspicion should be reserved for patients with progressive changes in size, focal lucency, or focal enhancement on serial imaging after RT

  4. Why victimology should stay positive: The ongoing need for positive victimology

    Directory of Open Access Journals (Sweden)

    Ronel Natti

    2015-01-01

    Full Text Available This paper presents the need for positive victimology and its unique contribution to victimology. Victimology presented a shift in attention and awareness in practice, research and theory, by focusing on victims of crime and of abuse of power, and on victims’ rights and victims’ services. Positive victimology indicates a more specified shift in attention and awareness, within the larger shift of victimology. This shift stands in line with positive psychology, positive criminology and the idea of victims’ victimology. It denotes an approach to provide the following, as much as possible: 1. A wide range of social responses to the victims and their victimization that victims can experience as positive, 2. Positive outcomes of healing and recovery for victims, and 3. Positive integration of victims. Within each of those, positive victimology suggests a pragmatic coordinated system that ranges from definitions of negative poles to those of positive ones. When moving towards the positive pole at any given coordinate, a sense of justice is an important factor that might reduce the impact of the harm. Support is also a crucial factor and at the very positive pole, stands human, inter-personal love.

  5. 40 CFR 63.941 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... another subpart that references the use of this subpart, then the definition in this subpart shall take precedence when implementing this subpart. Closure device means a cap, hatch, lid, plug, seal, valve, or... a surface impoundment cover when the device is secured in the closed position. Closure devices...

  6. Emotional complexity: Clarifying definitions and cultural correlates.

    Science.gov (United States)

    Grossmann, Igor; Huynh, Alex C; Ellsworth, Phoebe C

    2016-12-01

    There is much debate about the notion of emotional complexity (EC). The debate concerns both the definition and the meaning of ostensible cultural differences in the construct. Some scholars have defined EC as the experience of positive and negative emotions together rather than as opposites, a phenomenon that seems more common in East Asia than North America. Others have defined EC as the experience of emotions in a differentiated manner, a definition that has yet to be explored cross-culturally. The present research explores the role of dialectical beliefs and interdependence in explaining cultural differences in EC according to both definitions. In Study 1, we examined the prevalence of mixed (positive-negative) emotions in English-language online texts from 10 countries varying in interdependence and dialecticism. In Studies 2-3, we examined reports of emotional experiences in 6 countries, comparing intraindividual associations between pleasant and unpleasant states, prevalence of mixed emotions, and emotional differentiation across and within-situations. Overall, interdependence accounted for more cross-cultural and individual variance in EC measures than did dialecticism. Moreover, emotional differentiation was associated with the experience of positive and negative emotions together rather than as opposites, but only when tested on the same level of analysis (i.e., within vs. across-situations). (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  7. A Comprehensive Definition for Integrative Oncology.

    Science.gov (United States)

    Witt, Claudia M; Balneaves, Lynda G; Cardoso, Maria J; Cohen, Lorenzo; Greenlee, Heather; Johnstone, Peter; Kücük, Ömer; Mailman, Josh; Mao, Jun J

    2017-11-01

    Integrative oncology, which is generally understood to refer to the use of a combination of complementary medicine therapies in conjunction with conventional cancer treatments, has been defined in different ways, but there is no widely accepted definition. We sought to develop and establish a consensus for a comprehensive definition of the field of integrative oncology. We used a mixed-methods approach that included a literature analysis and a consensus procedure, including an interdisciplinary expert panel and surveys, to develop a comprehensive and acceptable definition for the term "integrative oncology." The themes identified in the literature and from the expert discussion were condensed into a two-sentence definition. Survey respondents had very positive views on the draft definition, and their comments helped to shape the final version. The final definition for integrative oncology is: "Integrative oncology is a patient-centered, evidence-informed field of cancer care that utilizes mind and body practices, natural products, and/or lifestyle modifications from different traditions alongside conventional cancer treatments. Integrative oncology aims to optimize health, quality of life, and clinical outcomes across the cancer care continuum and to empower people to prevent cancer and become active participants before,during, and beyond cancer treatment." This short and comprehensive definition for the term integrative oncology will facilitate a better understanding and communication of this emerging field. This definition will also drive focused and cohesive effort to advance the field of integrative oncology. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Solving large-scale sparse eigenvalue problems and linear systems of equations for accelerator modeling

    International Nuclear Information System (INIS)

    Gene Golub; Kwok Ko

    2009-01-01

    The solutions of sparse eigenvalue problems and linear systems constitute one of the key computational kernels in the discretization of partial differential equations for the modeling of linear accelerators. The computational challenges faced by existing techniques for solving those sparse eigenvalue problems and linear systems call for continuing research to improve on the algorithms so that ever increasing problem size as required by the physics application can be tackled. Under the support of this award, the filter algorithm for solving large sparse eigenvalue problems was developed at Stanford to address the computational difficulties in the previous methods with the goal to enable accelerator simulations on then the world largest unclassified supercomputer at NERSC for this class of problems. Specifically, a new method, the Hemitian skew-Hemitian splitting method, was proposed and researched as an improved method for solving linear systems with non-Hermitian positive definite and semidefinite matrices.

  9. Extension of PT-symmetric quantum mechanics to quantum field theory with cubic interaction

    International Nuclear Information System (INIS)

    Bender, Carl M.; Brody, Dorje C.; Jones, Hugh F.

    2004-01-01

    It has recently been shown that a non-Hermitian Hamiltonian H possessing an unbroken PT symmetry (i) has a real spectrum that is bounded below, and (ii) defines a unitary theory of quantum mechanics with positive norm. The proof of unitarity requires a linear operator C, which was originally defined as a sum over the eigenfunctions of H. However, using this definition to calculate C is cumbersome in quantum mechanics and impossible in quantum field theory. An alternative method is devised here for calculating C directly in terms of the operator dynamical variables of the quantum theory. This method is general and applies to a variety of quantum mechanical systems having several degrees of freedom. More importantly, this method is used to calculate the C operator in quantum field theory. The C operator is a time-independent observable in PT-symmetric quantum field theory

  10. Calculating the C operator in PT-symmetric quantum mechanics

    International Nuclear Information System (INIS)

    Bender, C.M.

    2004-01-01

    It has recently been shown that a non-Hermitian Hamiltonian H possessing an unbroken PT-symmetry (i) has a real spectrum that is bounded below, and (ii) defines a unitary theory of quantum mechanics with positive norm. The proof of unitarity requires a linear operator C, which was originally defined as a sum over the eigenfunctions of H. However, using this definition it is cumbersome to calculate C in quantum mechanics and impossible in quantum field theory. An alternative method is devised here for calculating C directly in terms of the operator dynamical variables of the quantum theory. This new method is general and applies to a variety of quantum mechanical systems having several degrees of freedom. More importantly, this method can be used to calculate the C operator in quantum field theory. The C operator is a new time-independent observable in PT-symmetric quantum field theory. (author)

  11. 40 CFR 63.901 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... subpart that references the use of this subpart, then the definition in this subpart shall take precedence when implementing this subpart. Closure device means a cap, hatch, lid, plug, seal, valve, or other type of fitting that, when the device is secured in the closed position, prevents or reduces air...

  12. EPOS 2012: European position paper on rhinosinusitis and nasal polyps 2012. A summary for otorhinolaryngologists

    NARCIS (Netherlands)

    Fokkens, Wytske J.; Lund, Valerie J.; Mullol, Joachim; Bachert, Claus; Alobid, Isam; Baroody, Fuad; Cohen, Noam; Cervin, Anders; Douglas, Richard; Gevaert, Philippe; Georgalas, Christos; Goossens, Herman; Harvey, Richard; Hellings, Peter; Hopkins, Claire; Jones, Nick; Joos, Guy; Kalogjera, Livije; Kern, Bob; Kowalski, Marek; Price, David; Riechelmann, Herbert; Schlosser, Rodney; Senior, Brent; Thomas, Mike; Toskala, Elina; Voegels, Richard; Wang, De Yun; Wormald, Peter John

    2012-01-01

    The European Position Paper on Rhinosinusitis and Nasal Polyps 2012 is the update of similar evidence based position papers published in 2005 and 2007. The document contains chapters on definitions and classification, we now also propose definitions for 'difficult to treat' rhinosinusitis, control

  13. Regularization of positive definite matrix fields based on multiplicative calculus

    NARCIS (Netherlands)

    Florack, L.M.J.; Bruckstein, A.M.; Haar Romeny, ter B.M.; Bronstein, A.M.; Bronstein, M.M.

    2012-01-01

    Multiplicative calculus provides a natural framework in problems involving positive images and positivity preserving operators. In increasingly important, complex imaging frameworks, such as diffusion tensor imaging, it complements standard calculus in a nontrivial way. The purpose of this article

  14. Matrix models with Penner interaction inspired by interacting ...

    Indian Academy of Sciences (India)

    distribution of structure with temperature calculated from the NL model .... where φi are the random Hermitian matrices of size (N × N) placed at each base position ..... PB thanks UGC for research fellowships and ND thanks CSIR Project No.

  15. A New Definition of Punishment

    Science.gov (United States)

    Hall, Philip S.

    2013-01-01

    Punishment is a procedure in which responses are followed by either the removal of positive reinforcement or the presentation of an aversive stimulus (Skinner, 1953) that results in a decrease in the frequency and/or intensity of the response (Azrin & Holtz, 1966). By definition, punishment seeks to stop unacceptable, unwanted, and bothersome…

  16. 40 CFR 63.921 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... subpart that references the use of this subpart, then the definition in this subpart shall take precedence...,” cargo tank trucks, and tank railcars. Closure device means a cover, cap, hatch, lid, plug, seal, valve... opening in a container or its cover when the device is secured in the closed position. Closure devices...

  17. 12 CFR 231.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... ELIGIBILITY FOR FINANCIAL INSTITUTION (REGULATION EE) § 231.2 Definitions. As used in this part, unless the...” contract). (d) Financial market means a market for a financial contract. (e) Gross mark-to-market positions... other person that controls, is controlled by, or is under common control with the person. (c) Financial...

  18. A method for weighted projections to the positive definite cone

    KAUST Repository

    Valkonen, Tuomo

    2014-06-24

    © 2014 Taylor & Francis. We study the numerical solution of the problem (Formula presented.) , where (Formula presented.) is a symmetric square matrix, and (Formula presented.) is a linear operator, such that (Formula presented.) is invertible. With (Formula presented.) the desired fractional duality gap, and (Formula presented.) the condition number of (Formula presented.) , we prove (Formula presented.) iteration complexity for a simple primal-dual interior point method directly based on those for linear programs with semi-definite constraints. We do not, however, require the numerically expensive scalings inherent in these methods to force fast convergence. For low-dimensional problems (Formula presented.), our numerical experiments indicate excellent performance and only a very slowly growing dependence of the convergence rate on (Formula presented.). While our algorithm requires somewhat more iterations than existing interior point methods, the iterations are cheaper. This gives better computational times.

  19. A method for weighted projections to the positive definite cone

    KAUST Repository

    Valkonen, Tuomo

    2014-01-01

    © 2014 Taylor & Francis. We study the numerical solution of the problem (Formula presented.) , where (Formula presented.) is a symmetric square matrix, and (Formula presented.) is a linear operator, such that (Formula presented.) is invertible. With (Formula presented.) the desired fractional duality gap, and (Formula presented.) the condition number of (Formula presented.) , we prove (Formula presented.) iteration complexity for a simple primal-dual interior point method directly based on those for linear programs with semi-definite constraints. We do not, however, require the numerically expensive scalings inherent in these methods to force fast convergence. For low-dimensional problems (Formula presented.), our numerical experiments indicate excellent performance and only a very slowly growing dependence of the convergence rate on (Formula presented.). While our algorithm requires somewhat more iterations than existing interior point methods, the iterations are cheaper. This gives better computational times.

  20. The mycotoxin definition reconsidered towards fungal cyclic depsipeptides.

    Science.gov (United States)

    Taevernier, Lien; Wynendaele, Evelien; De Vreese, Leen; Burvenich, Christian; De Spiegeleer, Bart

    2016-04-02

    Currently, next to the major classes, cyclic depsipeptides beauvericin and enniatins are also positioned as mycotoxins. However, as there are hundreds more fungal cyclic depsipeptides already identified, should these not be considered as mycotoxins as well? The current status of the mycotoxin definition revealed a lack of consistency, leading to confusion about what compounds should be called mycotoxins. Because this is of pivotal importance in risk assessment prioritization, a clear and quantitatively expressed mycotoxin definition is proposed, based on data of widely accepted mycotoxins. Finally, this definition is applied to a set of fungal cyclic depsipeptides, revealing that some of these should indeed be considered as mycotoxins.

  1. Nonequilibrium, steady-state electron transport with N-representable density matrices from the anti-Hermitian contracted Schrödinger equation

    Science.gov (United States)

    Rothman, Adam E.; Mazziotti, David A.

    2010-03-01

    We study molecular conductivity for a one-electron, bath-molecule-bath model Hamiltonian. The primary quantum-mechanical variable is the one-electron reduced density matrix (1-RDM). By identifying similarities between the steady-state Liouville equation and the anti-Hermitian contracted Schrödinger equation (ACSE) [D. A. Mazziotti, Phys. Rev. A 75, 022505 (2007)], we develop a way of enforcing nonequilibrium, steady-state behavior in a time-independent theory. Our results illustrate the relationship between current and voltage in molecular junctions assuming that the total number of electrons under consideration can be fixed across all driving potentials. The impetus for this work is a recent study by Subotnik et al. that also uses the 1-RDM to study molecular conductivity under different assumptions regarding the total number of electrons [J. E. Subotnik et al., J. Chem. Phys. 130, 144105 (2009)]. Unlike calculations in the previous study, our calculations result in 1-RDMs that are fully N-representable. The present work maintains N-representability through a bath-bath mixing that is related to a time-independent relaxation of the baths in the absence of the molecule, as governed by the ACSE. A lack of N-representability can be important since it corresponds to occupying energy states in the molecule or baths with more than one electron or hole (the absence of an electron) in violation of the Pauli principle. For this reason the present work may serve as an important, albeit preliminary, step in designing a 2-RDM/ACSE method for studying steady-state molecular conductivity with an explicit treatment of electron correlation.

  2. Delegation. Position Statement. Revised

    Science.gov (United States)

    Board, Connie; Bushmiaer, Margo; Davis-Alldritt, Linda; Fekaris, Nina; Morgitan, Judith; Murphy, M. Kathleen; Yow, Barbara

    2010-01-01

    It is the position of the National Association of School Nurses (NASN) that the delegation of nursing tasks in the school setting can be a valuable tool for the school nurse, when based on the nursing definition of delegation and in compliance with state nursing regulations and guidance. Delegation in school nursing is a complex process in which…

  3. 31 CFR 16.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Definitions. 16.2 Section 16.2 Money and Finance: Treasury Office of the Secretary of the Treasury REGULATIONS IMPLEMENTING THE PROGRAM... a position for which the rate of basic pay is not less than the minimum rate of basic pay for grade...

  4. 40 CFR 61.301 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... means a device that transfers heat liberated by burning fuel to fluids contained in tubes, except water... Benzene Transfer Operations § 61.301 Definitions. As used in this subpart, all terms not defined herein... vessels. Car-sealed means having a seal that is placed on the device used to change the position of a...

  5. Spirituality as a Positive Youth Development Construct: A Conceptual Review

    Directory of Open Access Journals (Sweden)

    Daniel T. L. Shek

    2012-01-01

    Full Text Available The concept of spirituality as a positive youth development construct is reviewed in this paper. Both broad and narrow definitions of spirituality are examined and a working definition of spirituality is proposed. Regarding theories of spirituality, different models pertinent to spiritual development and the relationship between spirituality and positive youth development are highlighted. Different ecological factors, particularly family and peer influences, were found to influence spirituality. Research on the influence of spirituality on adolescent developmental outcomes is examined. Finally, ways to promote adolescent spirituality are discussed.

  6. Positive mental health: is there a cross-cultural definition?

    Science.gov (United States)

    Vaillant, George E

    2012-06-01

    SEVEN MODELS FOR CONCEPTUALIZING POSITIVE MENTAL HEALTH ARE REVIEWED: mental health as above normal, epitomized by a DSM-IV's Global Assessment of Functioning (GAF) score of over 80; mental health as the presence of multiple human strengths rather than the absence of weaknesses; mental health conceptualized as maturity; mental health as the dominance of positive emotions; mental health as high socio-emotional intelligence; mental health as subjective well-being; mental health as resilience. Safeguards for the study of mental health are suggested, including the need to define mental health in terms that are culturally sensitive and inclusive, and the need to empirically and longitudinally validate criteria for mental health.

  7. Definition of IGRT

    International Nuclear Information System (INIS)

    Lief, Eugene

    2008-01-01

    Two definitions of image-guided radiation therapy (IGRT) are cited: 'Frequent imaging in the treatment room during a course of radiotherapy to guide the treatment process' and 'Any use of planar imaging, volumetric imaging or volumetric cine imaging, marker localization, marker tracking, patient surface imaging or patient surface tracking to improve the precision of radiation-therapy delivery'. Also cited are the sentences 'IGRT refers broadly to treatment delivery using modern imaging methods, such as CT, MRI, PET and Ultrasound, in target and non-target structures and in RT definition, design and delivery...' and 'IGRT includes, but is not limited to, 3DCRT, IMRT: stereotactic radiosurgery, stereotactic RT, and brachytherapy...'. Purposes include: Precise patient positioning; Automatic localization of bony structures or implanted fiducial markers; Imaging and positioning of soft tissue tumors and critical structures; Margin reduction and healthy organ sparing; and Delivering the desired dose distribution. On the negative side are the following factors: Physics staffing at treatment delivery Longer treatment times: 1 min. arm deployment, setup for scan, 1 min. gantry rotation - volume image acquisition, 30 sec. reconstruction (depends on resolution), 30 sec. load CT and CB into registration; Registration: from few sec. to few min.; Feasible if the number of treatments is low. The history of IGRT is mentioned, instrumentation is described using ample photographs, and many applications are shown. (P.A.)

  8. 40 CFR 63.822 - Definitions.

    Science.gov (United States)

    2010-07-01

    ..., labels, liners and wraps utilizing paper, plastic, film, aluminum foil, metalized or coated paper or film... Standards for the Printing and Publishing Industry § 63.822 Definitions. (a) All terms used in this subpart... device. Car-seal means a seal that is placed on a device that is used to change the position of a valve...

  9. Hermitian-to-quasi-Hermitian quantum phase transitions

    Czech Academy of Sciences Publication Activity Database

    Znojil, Miloslav

    Roč. 97, č. 4 ( 2018 ), č. článku 042117. ISSN 2469-9926 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : quantum phase transition * PT-symmetric * Herimiticity Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.925, year: 2016

  10. Additional Insights Into Problem Definition and Positioning From Social Science Comment on "Four Challenges That Global Health Networks Face".

    Science.gov (United States)

    Quissell, Kathryn

    2017-09-10

    Commenting on a recent editorial in this journal which presented four challenges global health networks will have to tackle to be effective, this essay discusses why this type of analysis is important for global health scholars and practitioners, and why it is worth understanding and critically engaging with the complexities behind these challenges. Focusing on the topics of problem definition and positioning, I outline additional insights from social science theory to demonstrate how networks and network researchers can evaluate these processes, and how these processes contribute to better organizing, advocacy, and public health outcomes. This essay also raises multiple questions regarding these processes for future research. © 2018 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

  11. Review of HRP Positions

    Energy Technology Data Exchange (ETDEWEB)

    Center for Reliability Studies

    2007-01-01

    The Department of Energy (DOE) Human Reliability Program (HRP), published as 10 CFR Part 712, is currently being reviewed and revised to address concerns identified during its implementation. Although these ''page changes'' primarily incorporate clarification of terms and language, the following discussion relates to broadening the definition of positions that require HRP certification that is found in {section}712.10.

  12. Review of Positional Nystagmus

    Directory of Open Access Journals (Sweden)

    José Ignacio BENITO-OREJAS

    2018-01-01

    Full Text Available Introduction and objective: Any change of position of the head (dynamic or static can trigger a nystagmus or increase the spontaneous. This nystagmus we call it positional. We intend to review in this chapter its definition, clinical features, etiology and the way of exploring it. Method: narrative review. Results: Positional vertigo is the most frequent vestibular disorder, and most of the times of peripheral cause. Characteristics of nystagmus or its association with other neurological symptoms are sufficient grounds to request a magnetic resonance, which will provide additional information on very few occasions. Discussion: The study of the positional nystagmus as a procedure to rule out central pathology has lost much of its relevance. Signs that Nylén defined mixed findings peripheral and central, making complex classification. Conclusion: Regardless of how to bring the patient change position (very slow or fast, if it appears an atypical nystagmus should rule out a central origin.

  13. Evaluation of the Components of the North Carolina Syndromic Surveillance System Heat Syndrome Case Definition.

    Science.gov (United States)

    Harduar Morano, Laurel; Waller, Anna E

    To improve heat-related illness surveillance, we evaluated and refined North Carolina's heat syndrome case definition. We analyzed North Carolina emergency department (ED) visits during 2012-2014. We evaluated the current heat syndrome case definition (ie, keywords in chief complaint/triage notes or International Classification of Diseases, Ninth Revision, Clinical Modification [ ICD-9-CM] codes) and additional heat-related inclusion and exclusion keywords. We calculated the positive predictive value and sensitivity of keyword-identified ED visits and manually reviewed ED visits to identify true positives and false positives. The current heat syndrome case definition identified 8928 ED visits; additional inclusion keywords identified another 598 ED visits. Of 4006 keyword-identified ED visits, 3216 (80.3%) were captured by 4 phrases: "heat ex" (n = 1674, 41.8%), "overheat" (n = 646, 16.1%), "too hot" (n = 594, 14.8%), and "heatstroke" (n = 302, 7.5%). Among the 267 ED visits identified by keyword only, a burn diagnosis or the following keywords resulted in a false-positive rate >95%: "burn," "grease," "liquid," "oil," "radiator," "antifreeze," "hot tub," "hot spring," and "sauna." After applying the revised inclusion and exclusion criteria, we identified 9132 heat-related ED visits: 2157 by keyword only, 5493 by ICD-9-CM code only, and 1482 by both (sensitivity = 27.0%, positive predictive value = 40.7%). Cases identified by keywords were strongly correlated with cases identified by ICD-9-CM codes (rho = .94, P definition through the use of additional inclusion and exclusion criteria substantially improved the accuracy of the surveillance system. Other jurisdictions may benefit from refining their heat syndrome case definition.

  14. Exploring the concept and use of positive deviance in nursing.

    Science.gov (United States)

    Gary, Jodie C

    2013-08-01

    Positive deviance involves an intentional act of breaking the rules in order to serve the greater good. For nurses, the rightness or wrongness of such actions will be judged by other people who are in charge of rules enforcement; but the decision to engage in positive deviance lies solely with the nurse. There is no uniform or consistent definition of positive deviance. This article uses the Walker and Avant method of concept analysis to explore and identify the essence of the term positive deviance in the nursing practice environment, provide a better understanding of the concept, and clarify its meaning for the nursing profession. In turn this led to an operational definition: positive deviance is intentional and honorable behavior that departs or differs from an established norm; contains elements of innovation, creativity, adaptability, or a combination thereof; and involves risk for the nurse. The concept of positive deviance is useful, offering nurses a basis for decision making when the normal, expected actions collide with the nurse's view of the right thing to do.

  15. Surveillance of paediatric traumatic brain injuries using the NEISS: choosing an appropriate case definition.

    Science.gov (United States)

    Thompson, Meghan C; Wheeler, Krista K; Shi, Junxin; Smith, Gary A; Groner, Jonathan I; Haley, Kathryn J; Xiang, Huiyun

    2014-01-01

    To evaluate the definition of traumatic brain injury (TBI) in the National Electronic Injury Surveillance System (NEISS) and compare TBI case ascertainment using NEISS vs. ICD-9-CM diagnosis coding. Two data samples from a NEISS participating emergency department (ED) in 2008 were compared: (1) NEISS records meeting the recommended NEISS TBI definition and (2) Hospital ED records meeting the ICD-9-CM CDC recommended TBI definition. The sensitivity and positive predictive value were calculated for the NEISS definition using the ICD-9-CM definition as the gold standard. Further analyses were performed to describe cases characterized as TBIs in both datasets and to determine why some cases were not classified as TBIs in both datasets. There were 1834 TBI cases captured by the NEISS and 1836 TBI cases captured by the ICD-9-CM coded ED record, but only 1542 were eligible for inclusion in NEISS. There were 1403 cases classified as TBIs by both the NEISS and ICD-9-CM diagnosis codes. The NEISS TBI definition had a sensitivity of 91.0% (95% CI = 89.6-92.4%) and positive predictive value of 76.5% (95% CI = 74.6-78.4%). Using the NEISS TBI definition presented in this paper would standardize and improve the accuracy of TBI research using the NEISS.

  16. TFOS DEWS II Definition and Classification Report.

    Science.gov (United States)

    Craig, Jennifer P; Nichols, Kelly K; Akpek, Esen K; Caffery, Barbara; Dua, Harminder S; Joo, Choun-Ki; Liu, Zuguo; Nelson, J Daniel; Nichols, Jason J; Tsubota, Kazuo; Stapleton, Fiona

    2017-07-01

    The goals of the TFOS DEWS II Definition and Classification Subcommittee were to create an evidence-based definition and a contemporary classification system for dry eye disease (DED). The new definition recognizes the multifactorial nature of dry eye as a disease where loss of homeostasis of the tear film is the central pathophysiological concept. Ocular symptoms, as a broader term that encompasses reports of discomfort or visual disturbance, feature in the definition and the key etiologies of tear film instability, hyperosmolarity, and ocular surface inflammation and damage were determined to be important for inclusion in the definition. In the light of new data, neurosensory abnormalities were also included in the definition for the first time. In the classification of DED, recent evidence supports a scheme based on the pathophysiology where aqueous deficient and evaporative dry eye exist as a continuum, such that elements of each are considered in diagnosis and management. Central to the scheme is a positive diagnosis of DED with signs and symptoms, and this is directed towards management to restore homeostasis. The scheme also allows consideration of various related manifestations, such as non-obvious disease involving ocular surface signs without related symptoms, including neurotrophic conditions where dysfunctional sensation exists, and cases where symptoms exist without demonstrable ocular surface signs, including neuropathic pain. This approach is not intended to override clinical assessment and judgment but should prove helpful in guiding clinical management and research. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. AUTHOR INDEX

    Indian Academy of Sciences (India)

    Uniqueness of solutions to Schrödinger equations on complex semi-simple Lie groups. 325. Chen Lili. On the compactly locally uniformly rotund points of Orlicz spaces. 471. Chu Jifeng. Positive solutions and eigenvalue intervals for nonlinear systems. 85. Clozel L. Equivariant embeddings of Hermitian sym- metric spaces.

  18. POVMs: a small but important step beyond standard quantum mechanics

    NARCIS (Netherlands)

    Muynck, de W.M.; Nieuwenhuizen, T.M.; Spicka, V.; Mehmani, B.; et al., xx

    2007-01-01

    It is the purpose of the present contribution to demonstrate that the generalization of the concept of a quantum mechanical oservable from the Hermitian operator of standard quantum mechanics to a positive operator-valued measure is not a peripheral issue, allegedly to be understood in terms of a

  19. The Great Gorilla Jump: An Introduction to Riemann Sums and Definite Integrals

    Science.gov (United States)

    Sealey, Vicki; Engelke, Nicole

    2012-01-01

    The great gorilla jump is an activity designed to allow calculus students to construct an understanding of the structure of the Riemann sum and definite integral. The activity uses the ideas of position, velocity, and time to allow students to explore familiar ideas in a new way. Our research has shown that introducing the definite integral as…

  20. Positive Emotion in Nature as a Precursor to Learning

    Science.gov (United States)

    Coleman, Tamara Chase

    2014-01-01

    This study was designed to examine the perception of learning in adults generated by the effect of a positive emotion-in this case, awe. For the study, a working definition of awe is an "impact-provoking reverence due to a powerful, positive emotional response to the natural world." This qualitative study used primarily face-to-face…

  1. Possible Relativistic Definitions of Parallax, Proper Motion and Radial Velocity

    National Research Council Canada - National Science Library

    Klioner, S

    2000-01-01

    .... In this paper, the authors briefly describe a relativistic model of space-based optical positional observations valid at a high level of accuracy, and suggest definitions of parallax, proper motion...

  2. Validation of a Syndromic Case Definition for Detecting Emergency Department Visits Potentially Related to Marijuana.

    Science.gov (United States)

    DeYoung, Kathryn; Chen, Yushiuan; Beum, Robert; Askenazi, Michele; Zimmerman, Cali; Davidson, Arthur J

    Reliable methods are needed to monitor the public health impact of changing laws and perceptions about marijuana. Structured and free-text emergency department (ED) visit data offer an opportunity to monitor the impact of these changes in near-real time. Our objectives were to (1) generate and validate a syndromic case definition for ED visits potentially related to marijuana and (2) describe a method for doing so that was less resource intensive than traditional methods. We developed a syndromic case definition for ED visits potentially related to marijuana, applied it to BioSense 2.0 data from 15 hospitals in the Denver, Colorado, metropolitan area for the period September through October 2015, and manually reviewed each case to determine true positives and false positives. We used the number of visits identified by and the positive predictive value (PPV) for each search term and field to refine the definition for the second round of validation on data from February through March 2016. Of 126 646 ED visits during the first period, terms in 524 ED visit records matched ≥1 search term in the initial case definition (PPV, 92.7%). Of 140 932 ED visits during the second period, terms in 698 ED visit records matched ≥1 search term in the revised case definition (PPV, 95.7%). After another revision, the final case definition contained 6 keywords for marijuana or derivatives and 5 diagnosis codes for cannabis use, abuse, dependence, poisoning, and lung disease. Our syndromic case definition and validation method for ED visits potentially related to marijuana could be used by other public health jurisdictions to monitor local trends and for other emerging concerns.

  3. Definition and epidemiology of acute respiratory distress syndrome.

    Science.gov (United States)

    Rezoagli, Emanuele; Fumagalli, Roberto; Bellani, Giacomo

    2017-07-01

    Fifty years ago, Ashbaugh and colleagues defined for the first time the acute respiratory distress syndrome (ARDS), one among the most challenging clinical condition of the critical care medicine. The scientific community worked over the years to generate a unified definition of ARDS, which saw its revisited version in the Berlin definition, in 2014. Epidemiologic information about ARDS is limited in the era of the new Berlin definition, and wide differences are reported among countries all over the world. Despite decades of study in the field of lung injury, ARDS is still so far under-recognized, with 2 out of 5 cases missed by clinicians. Furthermore, although advances of ventilator strategies in the management of ARDS associated with outcome improvements-such as protective mechanical ventilation, lower driving pressure, higher PEEP levels and prone positioning-ARDS appears to be undertreated and mortality remains elevated up to 40%. In this review, we cover the history that led to the current worldwide accepted Berlin definition of ARDS and we summarize the recent data regarding ARDS epidemiology.

  4. Toward a Strongly Interacting Scalar Higgs Particle

    International Nuclear Information System (INIS)

    Shalaby, Abouzeid M.; El-Houssieny, M.

    2008-01-01

    We calculate the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory. Rather than the corresponding Hermitian theory and due to the asymptotic freedom property of the theory, the vacuum energy does not blow up for large energy scales which is a good sign to solve the hierarchy problem when using this model to break the U(1)xSU(2) symmetry in the standard model. The theory is strongly interacting and in fact, all the dimensionful parameters in the theory like mass and energy are finite even for very high energy scales. Moreover, relative to the vacuum energy for the Hermitian φ 4 theory, the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 theory is tiny, which is a good sign toward the solution of the cosmological constant problem. Remarkably, these features of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory make it very plausible to be employed as a Higgs mechanism in the standard model instead of the problematic Hermitian Higgs mechanism

  5. Metric versus observable operator representation, higher spin models

    Science.gov (United States)

    Fring, Andreas; Frith, Thomas

    2018-02-01

    We elaborate further on the metric representation that is obtained by transferring the time-dependence from a Hermitian Hamiltonian to the metric operator in a related non-Hermitian system. We provide further insight into the procedure on how to employ the time-dependent Dyson relation and the quasi-Hermiticity relation to solve time-dependent Hermitian Hamiltonian systems. By solving both equations separately we argue here that it is in general easier to solve the former. We solve the mutually related time-dependent Schrödinger equation for a Hermitian and non-Hermitian spin 1/2, 1 and 3/2 model with time-independent and time-dependent metric, respectively. In all models the overdetermined coupled system of equations for the Dyson map can be decoupled algebraic manipulations and reduces to simple linear differential equations and an equation that can be converted into the non-linear Ermakov-Pinney equation.

  6. Relativistic model for statevector reduction

    International Nuclear Information System (INIS)

    Pearle, P.

    1991-04-01

    A relativistic quantum field model describing statevector reduction for fermion states is presented. The time evolution of the states is governed by a Schroedinger equation with a Hamiltonian that has a Hermitian and a non-Hermitian part. In addition to the fermions, the Hermitian part describes positive and negative energy mesons of equal mass, analogous to the longitudinal and timelike photons of electromagnetism. The meson-field-sum is coupled to the fermion field. This ''dresses'' each fermion so that, in the extreme nonrelativistic limit (non-moving fermions), a fermion in a position eigenstate is also in an eigenstate of the meson-field-difference with the Yukawa-potential as eigenvalue. However, the fermions do not interact: this is a theory of free dressed fermions. It is possible to obtain a stationary normalized ''vacuum'' state which satisfies two conditions analogous to the gauge conditions of electromagnetism (i.e., that the meson-field-difference, as well as its time derivative, give zero when applied to the vacuum state), to any desired degree of accuracy. The non-Hermitian part of the Hamiltonian contains the coupling of the meson-field-difference to an externally imposed c-number fluctuating white noise field, of the CSL (Continuous Spontaneous Localization) form. This causes statevector reduction, as is shown in the extreme nonrelativistic limit. For example, a superposition of spatially separated wavepackets of a fermion will eventually be reduced to a single wavepacket: the meson-field-difference discriminates among the Yukawa-potential ''handles'' attached to each wavepacket, thereby selecting one wavepacket to survive by the CSL mechanism. Analysis beyond that given in this paper is required to see what happens when the fermions are allowed to move. (It is possible that the ''vacuum'' state becomes involved in the dynamics so that the ''gauge'' conditions can no longer be maintained.) It is shown how to incorporate these ideas into quantum

  7. Evaluation of surveillance case definition in the diagnosis of leptospirosis, using the Microscopic Agglutination Test: a validation study.

    Science.gov (United States)

    Dassanayake, Dinesh L B; Wimalaratna, Harith; Agampodi, Suneth B; Liyanapathirana, Veranja C; Piyarathna, Thibbotumunuwe A C L; Goonapienuwala, Bimba L

    2009-04-22

    Leptospirosis is endemic in both urban and rural areas of Sri Lanka and there had been many out breaks in the recent past. This study was aimed at validating the leptospirosis surveillance case definition, using the Microscopic Agglutination Test (MAT). The study population consisted of patients with undiagnosed acute febrile illness who were admitted to the medical wards of the Teaching Hospital Kandy, from 1st July 2007 to 31st July 2008. The subjects were screened to diagnose leptospirosis according to the leptospirosis case definition. MAT was performed on blood samples taken from each patient on the 7th day of fever. Leptospirosis case definition was evaluated in regard to sensitivity, specificity and predictive values, using a MAT titre >or= 1:800 for confirming leptospirosis. A total of 123 patients were initially recruited of which 73 had clinical features compatible with the surveillance case definition. Out of the 73 only 57 had a positive MAT result (true positives) leaving 16 as false positives. Out of the 50 who didn't have clinical features compatible with the case definition 45 had a negative MAT as well (true negatives), therefore 5 were false negatives. Total number of MAT positives was 62 out of 123. According to these results the test sensitivity was 91.94%, specificity 73.77%, positive predictive value and negative predictive values were 78.08% and 90% respectively. Diagnostic accuracy of the test was 82.93%. This study confirms that the surveillance case definition has a very high sensitivity and negative predictive value with an average specificity in diagnosing leptospirosis, based on a MAT titre of >or= 1: 800.

  8. Competing definitions: a public policy analysis of the federal recreational fee demonstration program

    Science.gov (United States)

    Thomas A. E. More

    2003-01-01

    Problem definition theory specifies that however controls the definition of a problem is in a unique position to control debate over the issue, influence others, and determine the problem's place on the agenda. This paper uses a rhetorical analysis and a questionnaire survey of congressional aides to examine the federal Recreational Fee Demonstration Program....

  9. Validation of a published case definition for tuberculosis-associated immune reconstitution inflammatory syndrome.

    Science.gov (United States)

    Haddow, Lewis J; Moosa, Mahomed-Yunus S; Easterbrook, Philippa J

    2010-01-02

    To evaluate the International Network for the Study of HIV-associated IRIS (INSHI) case definitions for tuberculosis (TB)-associated immune reconstitution inflammatory syndrome (IRIS) in a South African cohort. Prospective cohort of 498 adult HIV-infected patients initiating antiretroviral therapy. Patients were followed up for 24 weeks and all clinical events were recorded. Events with TB-IRIS as possible cause were assessed by consensus expert opinion and INSHI case definition. Positive, negative, and chance-corrected agreement (kappa) were calculated, and reasons for disagreement were assessed. One hundred and two (20%) patients were receiving TB therapy at antiretroviral therapy initiation. Three hundred and thirty-three events were evaluated (74 potential paradoxical IRIS, 259 potential unmasking IRIS). Based on expert opinion, there were 18 cases of paradoxical IRIS associated with TB and/or other opportunistic disease. The INSHI criteria for TB-IRIS agreed in 13 paradoxical cases, giving positive agreement of 72.2%, negative agreement in 52/56 non-TB-IRIS events (92.9%), and kappa of 0.66. There were 19 unmasking TB-IRIS cases based on expert opinion, of which 12 were considered IRIS using the INSHI definition (positive agreement 63.2%). There was agreement in all 240 non-TB-IRIS events (negative agreement 100%) and kappa was 0.76. There was good agreement between the INSHI case definition for both paradoxical and unmasking TB-IRIS and consensus expert opinion. These results support the use of this definition in clinical and research practice, with minor caveats in its application.

  10. Reliability of case definitions for public health surveillance assessed by Round-Robin test methodology

    Directory of Open Access Journals (Sweden)

    Claus Hermann

    2006-05-01

    Full Text Available Abstract Background Case definitions have been recognized to be important elements of public health surveillance systems. They are to assure comparability and consistency of surveillance data and have crucial impact on the sensitivity and the positive predictive value of a surveillance system. The reliability of case definitions has rarely been investigated systematically. Methods We conducted a Round-Robin test by asking all 425 local health departments (LHD and the 16 state health departments (SHD in Germany to classify a selection of 68 case examples using case definitions. By multivariate analysis we investigated factors linked to classification agreement with a gold standard, which was defined by an expert panel. Results A total of 7870 classifications were done by 396 LHD (93% and all SHD. Reporting sensitivity was 90.0%, positive predictive value 76.6%. Polio case examples had the lowest reporting precision, salmonellosis case examples the highest (OR = 0.008; CI: 0.005–0.013. Case definitions with a check-list format of clinical criteria resulted in higher reporting precision than case definitions with a narrative description (OR = 3.08; CI: 2.47–3.83. Reporting precision was higher among SHD compared to LHD (OR = 1.52; CI: 1.14–2.02. Conclusion Our findings led to a systematic revision of the German case definitions and build the basis for general recommendations for the creation of case definitions. These include, among others, that testable yes/no criteria in a check-list format is likely to improve reliability, and that software used for data transmission should be designed in strict accordance with the case definitions. The findings of this study are largely applicable to case definitions in many other countries or international networks as they share the same structural and editorial characteristics of the case definitions evaluated in this study before their revision.

  11. Mathematical Definition, Mapping, and Detection of (Anti)Fragility

    OpenAIRE

    Taleb, Nassim N.; Douady, Raphael

    2012-01-01

    URL des Documents de travail : http://centredeconomiesorbonne.univ-paris1.fr/documents-de-travail/; Documents de travail du Centre d'Economie de la Sorbonne 2014.93 - ISSN : 1955-611X; We provide a mathematical definition of fragility and antifragility as negative or positive sensitivity to a semi-measure of dispersion and volatility (a variant of negative or positive "vega") and examine the link to nonlinear effects. We integrate model error (and biases) into the fragile or antifragile conte...

  12. Cross-cultural comparison of successful aging definitions between Chinese and Hmong elders in the United States

    OpenAIRE

    Nguyen, Annie L.; Seal, David W.

    2014-01-01

    The purpose of the study was to elicit the definitions of successful aging according to Chinese and Hmong elders living in Milwaukee, WI. In-depth semi-structured interviews were conducted with 44 elders (Hmong n=21 and Chinese n=23). Findings show some similarities in the Chinese and Hmong elders’ definitions though specific cultural differences exist. Chinese elders emphasized physical health and mobility, mental health, positive attitudes, shedding responsibilities, positive family relatio...

  13. Does the applied polytrauma definition notably influence outcome and patient population? - a retrospective analysis.

    Science.gov (United States)

    Frenzel, Stephan; Krenn, Philipp; Heinz, Thomas; Negrin, Lukas Leopold

    2017-08-31

    Although the term "polytrauma" has been in use for decades, no generally accepted definition exists. The aim of this study was to demonstrate that different polytrauma definitions applied to a specific patient population result in diverse subgroups of individuals, who in turn present a varying outcome. All patients (≥18 years) treated at our level I trauma center within a time period of three years were classified according to 11 selected polytrauma definitions and included in our study, if they were rated "polytraumatized" by at least one of these definitions. All patients, who met the criteria of a certain definition, were combined to the relevant definition-positive group, thus resulting in 11 patient subgroups. Their demographic data (number of patients, mean patient age, mean Injury Severity Score value, median number of ventilator days, median length of stay at the intensive care unit and at the hospital, mortality rate and odds ratio) were statistically compared. Three hundred seventy-five patients (73% male) with a mean age of 47 years met the inclusion criteria and were allocated to the relevant subgroups; their patient number varied from 55 to 346 and their mean Injury Severity Score value ranged from 4 to 75. Not surprisingly, all examined parameters were subject to variations. Whereas most definition-positive groups showed a mortality rate of about 21% to 30%, 18% of the individuals, who met the criteria according to Blacker, and 40% of the polytrauma victims according to Schalamon died. The Pape 1-, Schalamon-, and Berlin-positive groups presented a significant odds ratio with regard to mortality that considerably exceeded 1. A polytrauma definition can only be a reliable tool in classifying trauma victims if it provides a significant odds ratio with regard to mortality that considerably exceeds 1 and if it succeeds in capturing patients with multiple severe injuries and a higher mortality rate without reducing the number of polytraumatized

  14. Clinician practice and the National Healthcare Safety Network definition for the diagnosis of catheter-associated urinary tract infection.

    Science.gov (United States)

    Al-Qas Hanna, Fadi; Sambirska, Oksana; Iyer, Sugantha; Szpunar, Susanna; Fakih, Mohamad G

    2013-12-01

    The National Healthcare Safety Network (NHSN) definition for catheter-associated urinary tract infection (CAUTI) is used to evaluate improvements in CAUTI prevention efforts. We assessed whether clinician practice was reflective of the NHSN definition. We evaluated all adult inpatients hospitalized between July 2010 and June 2011, with a first positive urine culture > 48 hours of admission obtained while catheterized or within 48 hours of catheter discontinuation. Data comprised patients' signs, symptoms, and diagnostic tests; clinician's diagnosis; and the impression of the infectious diseases (ID) consultant. The clinician's practice was compared with the NHSN definition and the ID consultant's impression. Antibiotics were initiated by clinicians to treat CAUTI in 216 of 387 (55.8%) cases, with 119 of 387 (30.7%) fitting the NHSN CAUTI definition, and 63 of 211 (29.9%) considered by ID to have a CAUTI. The sensitivity, specificity, and positive and negative predictive values of a clinician diagnosis of CAUTI were 62.2%, 47%, 34.3%, and 73.7% when compared with NHSN CAUTI definition (n = 387) and 100%, 57.4%, 50%, and 100% when compared with the ID consultant evaluation (n = 211), respectively. The positive predictive value of the NHSN CAUTI definition was 35.1% when compared with the ID consultant's impression (n = 211). NHSN CAUTI definition did not reflect clinician or ID consultant practices. Our findings reflect the differences between surveillance definitions and clinical practice. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  15. INNOVATION MANAGER AND HIS POSITION IN COMPANY

    Directory of Open Access Journals (Sweden)

    KATEŘINA HRAZDILOVÁ BOČKOVÁ

    2010-12-01

    Full Text Available The presented paper deals with the importance of innovation manager in company. It analyses the actual state of definition of innovation manager in companies, it is dealing with their qualities and qualities of ideal innovation manager. The paper solves the placement of position of innovation manager into the company organization structure. It recommends the ideal placement of innovation manager position in the organization structure in company working in “Production, sale and operation of amusement and gaming technology”.

  16. Innovation manager and his position in company

    Directory of Open Access Journals (Sweden)

    Kateřina Hrazdilová Bočková

    2011-04-01

    Full Text Available The presented paper deals with the importance of innovation manager in company. It analyses the actual state of definition of innovation manager in companies, it is dealing with their qualities and qualities of ideal innovation manager. The paper solves the placement of position of innovation manager into the company organization structure. It recommends the ideal placement of innovation manager position in the organization structure in company working in “Production, sale and operation of amusement and gaming technology”.

  17. Social Entrepreneurship: Definition and Boundaries

    Directory of Open Access Journals (Sweden)

    Samer Abu-Saifan

    2012-02-01

    Full Text Available While individuals may be publicly recognized as social entrepreneurs for their contributions to improve the welfare of communities, the field of social entrepreneurship continues to struggle to gain academic legitimacy. Social entrepreneurship is a term in search of a good definition. The current use of the term seems vague and limitless; it needs boundaries to demarcate its function. The lack of a common definition hinders research and raises questions about which social or profit-making activities fall within the spectrum of social entrepreneurship. To become an important stream in the entrepreneurship literature, social entrepreneurship needs to be properly defined and it requires a theoretical framework that links it to the theory of entrepreneurship. This article builds on the literature to define social entrepreneurship, discusses the boundaries of socially-oriented entrepreneurial activities, and positions the social entrepreneur in the spectrum of entrepreneurship.

  18. Generalized Choi states and 2-distillability of quantum states

    Science.gov (United States)

    Chen, Lin; Tang, Wai-Shing; Yang, Yu

    2018-05-01

    We investigate the distillability of bipartite quantum states in terms of positive and completely positive maps. We construct the so-called generalized Choi states and show that it is distillable when it has negative partial transpose. We convert the distillability problem of 2-copy n× n Werner states into the determination of the positivity of an Hermitian matrix. We obtain several sufficient conditions by which the positivity holds. Further, we investigate the case n=3 by the classification of 2× 3× 3 pure states.

  19. Covariant and consistent anomalies in two dimensions in path-integral formulation

    International Nuclear Information System (INIS)

    Joglekar, S.D.; Saini, G.

    1993-01-01

    We give a definition of a one-parameter family of regularized chiral currents in a chiral non-Abelian gauge theory in two dimensions in path-integral formulation. We show that covariant and consistent currents are obtained from this family by selecting two specific values of the free parameter, and thus our regularization interpolates between these two. Our procedure uses chiral bases constructed from eigenfunctions of the same operator for ψ L and anti ψ L . Definition of integration measure and regularization is done in terms of the same Hermitian operator D α =∂+iαA. Covariant and consistent currents (and indeed the entire family) are classically conserved. Difference with previous works are explained, in particular, that an anomaly in the general basis does differ from the Jacobian contribution. (orig.)

  20. Acute respiratory distress syndrome: the Berlin Definition.

    Science.gov (United States)

    Ranieri, V Marco; Rubenfeld, Gordon D; Thompson, B Taylor; Ferguson, Niall D; Caldwell, Ellen; Fan, Eddy; Camporota, Luigi; Slutsky, Arthur S

    2012-06-20

    The acute respiratory distress syndrome (ARDS) was defined in 1994 by the American-European Consensus Conference (AECC); since then, issues regarding the reliability and validity of this definition have emerged. Using a consensus process, a panel of experts convened in 2011 (an initiative of the European Society of Intensive Care Medicine endorsed by the American Thoracic Society and the Society of Critical Care Medicine) developed the Berlin Definition, focusing on feasibility, reliability, validity, and objective evaluation of its performance. A draft definition proposed 3 mutually exclusive categories of ARDS based on degree of hypoxemia: mild (200 mm Hg < PaO2/FIO2 ≤ 300 mm Hg), moderate (100 mm Hg < PaO2/FIO2 ≤ 200 mm Hg), and severe (PaO2/FIO2 ≤ 100 mm Hg) and 4 ancillary variables for severe ARDS: radiographic severity, respiratory system compliance (≤40 mL/cm H2O), positive end-expiratory pressure (≥10 cm H2O), and corrected expired volume per minute (≥10 L/min). The draft Berlin Definition was empirically evaluated using patient-level meta-analysis of 4188 patients with ARDS from 4 multicenter clinical data sets and 269 patients with ARDS from 3 single-center data sets containing physiologic information. The 4 ancillary variables did not contribute to the predictive validity of severe ARDS for mortality and were removed from the definition. Using the Berlin Definition, stages of mild, moderate, and severe ARDS were associated with increased mortality (27%; 95% CI, 24%-30%; 32%; 95% CI, 29%-34%; and 45%; 95% CI, 42%-48%, respectively; P < .001) and increased median duration of mechanical ventilation in survivors (5 days; interquartile [IQR], 2-11; 7 days; IQR, 4-14; and 9 days; IQR, 5-17, respectively; P < .001). Compared with the AECC definition, the final Berlin Definition had better predictive validity for mortality, with an area under the receiver operating curve of 0.577 (95% CI, 0.561-0.593) vs 0.536 (95% CI, 0.520-0.553; P

  1. Random matrix ensembles for PT-symmetric systems

    International Nuclear Information System (INIS)

    Graefe, Eva-Maria; Mudute-Ndumbe, Steve; Taylor, Matthew

    2015-01-01

    Recently much effort has been made towards the introduction of non-Hermitian random matrix models respecting PT-symmetry. Here we show that there is a one-to-one correspondence between complex PT-symmetric matrices and split-complex and split-quaternionic versions of Hermitian matrices. We introduce two new random matrix ensembles of (a) Gaussian split-complex Hermitian; and (b) Gaussian split-quaternionic Hermitian matrices, of arbitrary sizes. We conjecture that these ensembles represent universality classes for PT-symmetric matrices. For the case of 2 × 2 matrices we derive analytic expressions for the joint probability distributions of the eigenvalues, the one-level densities and the level spacings in the case of real eigenvalues. (fast track communication)

  2. 29 CFR 825.123 - Unable to perform the functions of the position.

    Science.gov (United States)

    2010-07-01

    ... position within the meaning of the Americans with Disabilities Act (ADA), as amended, 42 U.S.C. 12101 et... 29 Labor 3 2010-07-01 2010-07-01 false Unable to perform the functions of the position. 825.123... Act § 825.123 Unable to perform the functions of the position. (a) Definition. An employee is “unable...

  3. Definition and classification of chronic kidney disease : A position statement from Kidney Disease: Improving Global Outcomes (KDIGO)

    NARCIS (Netherlands)

    Levey, Andrew S.; Eckardt, Kai Uwe; Tsukamoto, Yusuke; Levin, Adeera; Coresh, Josef; Rossert, Jerome; de Zeeuw, Dick; Hostetter, Thomas H.; Lameire, Norbert; Eknoyan, Garabed

    Chronic kidney disease (CKD) is a worldwide public health problem, with adverse outcomes of kidney failure, cardiovascular disease (CVD), and premature death. A simple definition and classification of kidney disease is necessary for international development and implementation of clinical practice

  4. Hidden Curriculum: An Analytical Definition

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Andarvazh

    2018-03-01

    Full Text Available Background: The concept of hidden curriculum was first used by Philip Jackson in 1968, and Hafferty brought this concept to the medical education. Many of the subjects that medical students learn are attributed to this curriculum. So far several definitions have been presented for the hidden curriculum, which on the one hand made this concept richer, and on the other hand, led to confusion and ambiguity.This paper tries to provide a clear and comprehensive definition of it.Methods: In this study, concept analysis of McKenna method was used. Using keywords and searching in the databases, 561 English and 26 Persian references related to the concept was found, then by limitingthe research scope, 125 abstracts and by finding more relevant references, 55 articles were fully studied.Results: After analyzing the definitions by McKenna method, the hidden curriculum is defined as follows: The hidden curriculum is a hidden, powerful, intrinsic in organizational structure and culture and sometimes contradictory message, conveyed implicitly and tacitly in the learning environment by structural and human factors and its contents includes cultural habits and customs, norms, values, belief systems, attitudes, skills, desires and behavioral and social expectations can have a positive or negative effect, unplanned, neither planners nor teachers, nor learners are aware of it. The ultimate consequence of the hidden curriculum includes reproducing the existing class structure, socialization, and familiarizing learners for transmission and joining the professional world.Conclusion: Based on the concept analysis, we arrived at an analytical definition of the hidden curriculum that could be useful for further studies in this area.Keywords: CONCEPT ANALYSIS, HIDDEN CURRICULUM, MCKENNA’S METHOD

  5. [Acute schizophrenia concept and definition: investigation of a French psychiatrist population].

    Science.gov (United States)

    Baylé, F J; Misdrahi, D; Llorca, P M; Lançon, C; Olivier, V; Quintin, P; Azorin, J M

    2005-01-01

    For schizophrenic disorders, the clinical conception of "acute state" is widely used in clinical settings to assess the effectiveness of therapeutic programs as well as epidemiological studies. Schizophrenic-specific symptomatology modification, need for hospitalization, significant change in care, disturbances in social behavior or suicide attempts were all used to define acute schizophrenic state. The decision to hospitalize is frequently used to define acute state but refers to multiple factors such as mood disorder, suicide attempts, drug abuse or social and environmental problems. Indeed, several and distinct definitions in a criteria basis form are available but no one has reached consensus. Because recognition of acute schizophrenic state remains based on the subjective clinician's advice, epidemiological and therapeutic studies fail in validity and reliability. The aim of the study was to evaluate how a population of French psychiatrists define criteria and therapeutic targets of acute schizophrenic state in their clinical practice. Psychiatrists filled out a self administered interview. At the time the interview was given, clinicians were notified that they were participating in a clinical consensus survey about schizophrenia. Six major indicators for acute state definition based on the literature data were proposed: general schizophrenic symptomatology modification (depression, anxiety, agitation, impulsivity/aggressiveness), specific schizophrenic symptomatology modification (positive symptoms, negative symptoms, disorganization), need for hospitalization, significant change in care, disturbance in social behavior and lastly, suicidal behavior. Minimal duration (1.2 or 4 weeks) of general and specific schizophrenic symptomatology modification required to define acute state were evaluated. The booklet included the 30 PANSS symptoms listed with their definitions. Among this symptom list, clinicians were instructed to select the ten criteria which they

  6. Resilience as a Positive Youth Development Construct: A Conceptual Review

    Directory of Open Access Journals (Sweden)

    Tak Yan Lee

    2012-01-01

    Full Text Available The concept of resilience is reviewed from a range of disciplinary perspectives in this paper. Both broad and narrow definitions of resilience are highlighted and a working definition of resilience is proposed to inform research, policy and practice. Different psychological, social and ecological protective factors, particularly competence, optimism, and bonding to family and cultural beliefs are highlighted. Theoretical relationships between resilience and positive youth development are examined with an attempt to erase misunderstandings. Finally, how schools can promote resilience among students is discussed.

  7. [Problems with current hypertension definition in children].

    Science.gov (United States)

    Peco-Antić, Amira

    2008-01-01

    The Task Force data have added immeasurably to our understanding of the normal distribution of blood pressure in children. However, the manner in which arterial hypertension is defined in children is not without problems. The main problem is that the current definition of hypertension in children is not based on the end-organ damage assessment, but on the blood pressure height-related percentile distribution of healthy reference population. This could be overcome by introducing the relationship of blood pressure values with sensitive markers of hypertensive sequelae (such as carotid intimal-medial thickness, left ventricle mass index, retinal arteriolar narrowing and arteriovenous nicking as well as microalbumin urinary excretion) to define better the specific blood pressure values with outcomes. Furthermore, the current definition of hypertension based on the demographic and clinical characteristics of the reference population does not consider the normal evolution of reference population, as well as its ethnic differences. In addition, being based on the single occasion measurement in quite position it does not account for the possibility of transient, stress induced elevations in blood pressure known as white coat hypertension. Therefore, incorporation ambulatory 24 h blood pressure data into the definition of arterial hypertension in children may increase the definition reliability for clinical decision - making, although for such reliability the paediatric normative ambulatory blood pressure data should be improved.

  8. 13 CFR 120.1700 - Definitions used in subpart J.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Definitions used in subpart J. 120.1700 Section 120.1700 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1700...

  9. Definition of Videogames

    Directory of Open Access Journals (Sweden)

    Grant Tavinor

    2008-01-01

    Full Text Available Can videogames be defined? The new field of games studies has generated three somewhat competing models of videogaming that characterize games as new forms of gaming, narratives, and interactive fictions. When treated as necessary and sufficient condition definitions, however, each of the three approaches fails to pick out all and only videogames. In this paper I argue that looking more closely at the formal qualities of definition helps to set out the range of definitional options open to the games theorist. A disjunctive definition of videogaming seems the most appropriate of these definitional options. The disjunctive definition I offer here is motivated by the observation that there is more than one characteristic way of being a videogame.

  10. Defining SNAP by cross-sectional and longitudinal definitions of neurodegeneration.

    Science.gov (United States)

    Wisse, L E M; Das, S R; Davatzikos, C; Dickerson, B C; Xie, S X; Yushkevich, P A; Wolk, D A

    2018-01-01

    Suspected non-Alzheimer's pathophysiology (SNAP) is a biomarker driven designation that represents a heterogeneous group in terms of etiology and prognosis. SNAP has only been identified by cross-sectional neurodegeneration measures, whereas longitudinal measures might better reflect "active" neurodegeneration and might be more tightly linked to prognosis. We compare neurodegeneration defined by cross-sectional 'hippocampal volume' only (SNAP/L-) versus both cross-sectional and longitudinal 'hippocampal atrophy rate' (SNAP/L+) and investigate how these definitions impact prevalence and the clinical and biomarker profile of SNAP in Mild Cognitive Impairment (MCI). 276 MCI patients from ADNI-GO/2 were designated amyloid "positive" (A+) or "negative" (A-) based on their florbetapir scan and neurodegeneration 'positive' or 'negative' based on cross-sectional hippocampal volume and longitudinal hippocampal atrophy rate. 74.1% of all SNAP participants defined by the cross-sectional definition of neurodegeneration also met the longitudinal definition of neurodegeneration, whereas 25.9% did not. SNAP/L+ displayed larger white matter hyperintensity volume, a higher conversion rate to dementia over 5 years and a steeper decline on cognitive tasks compared to SNAP/L- and the A- CN group. SNAP/L- had more abnormal values on neuroimaging markers and worse performance on cognitive tasks than the A- CN group, but did not show a difference in dementia conversion rate or longitudinal cognition. Using a longitudinal definition of neurodegeneration in addition to a cross-sectional one identifies SNAP participants with significant cognitive decline and a worse clinical prognosis for which cerebrovascular disease may be an important driver.

  11. Computer-assisted expert case definition in electronic health records.

    Science.gov (United States)

    Walker, Alexander M; Zhou, Xiaofeng; Ananthakrishnan, Ashwin N; Weiss, Lisa S; Shen, Rongjun; Sobel, Rachel E; Bate, Andrew; Reynolds, Robert F

    2016-02-01

    To describe how computer-assisted presentation of case data can lead experts to infer machine-implementable rules for case definition in electronic health records. As an illustration the technique has been applied to obtain a definition of acute liver dysfunction (ALD) in persons with inflammatory bowel disease (IBD). The technique consists of repeatedly sampling new batches of case candidates from an enriched pool of persons meeting presumed minimal inclusion criteria, classifying the candidates by a machine-implementable candidate rule and by a human expert, and then updating the rule so that it captures new distinctions introduced by the expert. Iteration continues until an update results in an acceptably small number of changes to form a final case definition. The technique was applied to structured data and terms derived by natural language processing from text records in 29,336 adults with IBD. Over three rounds the technique led to rules with increasing predictive value, as the experts identified exceptions, and increasing sensitivity, as the experts identified missing inclusion criteria. In the final rule inclusion and exclusion terms were often keyed to an ALD onset date. When compared against clinical review in an independent test round, the derived final case definition had a sensitivity of 92% and a positive predictive value of 79%. An iterative technique of machine-supported expert review can yield a case definition that accommodates available data, incorporates pre-existing medical knowledge, is transparent and is open to continuous improvement. The expert updates to rules may be informative in themselves. In this limited setting, the final case definition for ALD performed better than previous, published attempts using expert definitions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Validation of a case definition to define hypertension using administrative data.

    Science.gov (United States)

    Quan, Hude; Khan, Nadia; Hemmelgarn, Brenda R; Tu, Karen; Chen, Guanmin; Campbell, Norm; Hill, Michael D; Ghali, William A; McAlister, Finlay A

    2009-12-01

    We validated the accuracy of case definitions for hypertension derived from administrative data across time periods (year 2001 versus 2004) and geographic regions using physician charts. Physician charts were randomly selected in rural and urban areas from Alberta and British Columbia, Canada, during years 2001 and 2004. Physician charts were linked with administrative data through unique personal health number. We reviewed charts of approximately 50 randomly selected patients >35 years of age from each clinic within 48 urban and 16 rural family physician clinics to identify physician diagnoses of hypertension during the years 2001 and 2004. The validity indices were estimated for diagnosed hypertension using 3 years of administrative data for the 8 case-definition combinations. Of the 3,362 patient charts reviewed, the prevalence of hypertension ranged from 18.8% to 33.3%, depending on the year and region studied. The administrative data hypertension definition of "2 claims within 2 years or 1 hospitalization" had the highest validity relative to the other definitions evaluated (sensitivity 75%, specificity 94%, positive predictive value 81%, negative predictive value 92%, and kappa 0.71). After adjustment for age, sex, and comorbid conditions, the sensitivities between regions, years, and provinces were not significantly different, but the positive predictive value varied slightly across geographic regions. These results provide evidence that administrative data can be used as a relatively valid source of data to define cases of hypertension for surveillance and research purposes.

  13. Safety, reliability, and validity of a physiologic definition of bronchopulmonary dysplasia.

    Science.gov (United States)

    Walsh, Michele C; Wilson-Costello, Deanna; Zadell, Arlene; Newman, Nancy; Fanaroff, Avroy

    2003-09-01

    Bronchopulmonary dysplasia (BPD) is the focus of many intervention trials, yet the outcome measure when based solely on oxygen administration may be confounded by differing criteria for oxygen administration between physicians. Thus, we wished to define BPD by a standardized oxygen saturation monitoring at 36 weeks corrected age, and compare this physiologic definition with the standard clinical definition of BPD based solely on oxygen administration. A total of 199 consecutive very low birthweight infants (VLBW, 501 to 1500 g birthweight) were assessed prospectively at 36+/-1 weeks corrected age. Neonates on positive pressure support or receiving >30% supplemental oxygen were assigned the outcome BPD. Those receiving or =88% for 60 minutes) or "BPD" (saturation reliability, test-retest reliability, and validity of the physiologic definition vs the clinical definition were assessed. A total of 199 VLBW were assessed, of whom 45 (36%) were diagnosed with BPD by the clinical definition of oxygen use at 36 weeks corrected age. The physiologic definition identified 15 infants treated with oxygen who successfully passed the saturation monitoring test in room air. The physiologic definition diagnosed BPD in 30 (24%) of the cohort. All infants were safely studied. The test was highly reliable (inter-rater reliability, kappa=1.0; test-retest reliability, kappa=0.83) and highly correlated with discharge home in oxygen, length of hospital stay, and hospital readmissions in the first year of life. The physiologic definition of BPD is safe, feasible, reliable, and valid and improves the precision of the diagnosis of BPD. This may be of benefit in future multicenter clinical trials.

  14. Big data and positive change in the developing world

    NARCIS (Netherlands)

    Taylor, L.; Cowls, J.; Schroeder, R.; Meyer, E.T.

    2014-01-01

    This paper is the product of a workshop that brought together practitioners, researchers, and data experts to discuss how big data is becoming a resource for positive social change in low- and middle-income countries (LMICs). We include in our definition of big data sources such as social media

  15. Hamiltonian Dynamics and Positive Energy in General Relativity

    Energy Technology Data Exchange (ETDEWEB)

    Deser, S. [Physics Department, Brandeis University, Waltham, MA (United States)

    1969-07-15

    A review is first given of the Hamiltonian formulation of general relativity; the gravitational field is a self-interacting massless spin-two system within the framework of ordinary Lorentz covariant field theory. The recently solved problem of positive-definiteness of the field energy is then discussed. The latter, a conserved functional of the dynamical variables, is shown to have only one extremum, a local minimum, which is the vacuum state (flat space). This implies positive energy for the field, with the vacuum as ground-state. Similar results hold when minimally coupled matter is present. (author)

  16. Scope Definition

    DEFF Research Database (Denmark)

    Bjørn, Anders; Owsianiak, Mikołaj; Laurent, Alexis

    2018-01-01

    The scope definition is the second phase of an LCA. It determines what product systems are to be assessed and how this assessment should take place. This chapter teaches how to perform a scope definition. First, important terminology and key concepts of LCA are introduced. Then, the nine items...... making up a scope definition are elaborately explained: (1) Deliverables. (2) Object of assessment, (3) LCI modelling framework and handling of multifunctional processes, (4) System boundaries and completeness requirements, (5) Representativeness of LCI data, (6) Preparing the basis for the impact...... assessment, (7) Special requirements for system comparisons, (8) Critical review needs and (9) Planning reporting of results. The instructions relate both to the performance and reporting of a scope definition and are largely based on ILCD....

  17. Non-isospectrality of the generalized Swanson Hamiltonian and harmonic oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Midya, Bikashkali; Dube, P P; Roychoudhury, Rajkumar, E-mail: bikash.midya@gmail.com, E-mail: ppdube1@gmail.com, E-mail: raj@isical.ac.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India)

    2011-02-11

    The generalized Swanson Hamiltonian H{sub GS}=w(a-tilde a-tilde{sup {dagger}}+1/2)+{alpha}{alpha}-tilde{sup 2}+{beta}a-tilde{sup {dagger}}{sup 2} with a-tilde = A(x) d/dx + B(x) can be transformed into an equivalent Hermitian Hamiltonian with the help of a similarity transformation. It is shown that the equivalent Hermitian Hamiltonian can be further transformed into the harmonic oscillator Hamiltonian so long as [a-ilde,a-tilde{sup {dagger}}]=constant. However, the main objective of this communication is to show that though the commutator of a-tilde and a-tilde{sup {dagger}} is constant, the generalized Swanson Hamiltonian is not necessarily isospectral to the harmonic oscillator. The reason for this anomaly is discussed in the framework of position-dependent mass models by choosing A(x) as the inverse square root of the mass function. (fast track communication)

  18. Claims-based definition of death in Japanese claims database: validity and implications.

    Science.gov (United States)

    Ooba, Nobuhiro; Setoguchi, Soko; Ando, Takashi; Sato, Tsugumichi; Yamaguchi, Takuhiro; Mochizuki, Mayumi; Kubota, Kiyoshi

    2013-01-01

    For the pending National Claims Database in Japan, researchers will not have access to death information in the enrollment files. We developed and evaluated a claims-based definition of death. We used healthcare claims and enrollment data between January 2005 and August 2009 for 195,193 beneficiaries aged 20 to 74 in 3 private health insurance unions. We developed claims-based definitions of death using discharge or disease status and Charlson comorbidity index (CCI). We calculated sensitivity, specificity and positive predictive values (PPVs) using the enrollment data as a gold standard in the overall population and subgroups divided by demographic and other factors. We also assessed bias and precision in two example studies where an outcome was death. The definition based on the combination of discharge/disease status and CCI provided moderate sensitivity (around 60%) and high specificity (99.99%) and high PPVs (94.8%). In most subgroups, sensitivity of the preferred definition was also around 60% but varied from 28 to 91%. In an example study comparing death rates between two anticancer drug classes, the claims-based definition provided valid and precise hazard ratios (HRs). In another example study comparing two classes of anti-depressants, the HR with the claims-based definition was biased and had lower precision than that with the gold standard definition. The claims-based definitions of death developed in this study had high specificity and PPVs while sensitivity was around 60%. The definitions will be useful in future studies when used with attention to the possible fluctuation of sensitivity in some subpopulations.

  19. Ventriculostomy-associated infection: a new, standardized reporting definition and institutional experience.

    Science.gov (United States)

    Gozal, Yair M; Farley, Chad W; Hanseman, Dennis J; Harwell, Daniel; Magner, Mark; Andaluz, Norberto; Shutter, Lori

    2014-08-01

    Shortcomings created by the lack of both a uniform definition of ventriculostomy-associated infection (VAI) and reporting standards have led to widely ranging infections rates (2-24%) whose significance is uncertain. We propose a standardized definition of VAI and a consistent reporting format compliant with Centers for Disease Control and Prevention (CDC) for device-related infections. Using those parameters to establish an infection-control surveillance program, we report our 4-year institutional VAI rates. In this prospective study covering ventriculostomy utilization (October 2006-December 2010), 498 patients had a total of 4,673 ventriculostomy days. By review of the literature and our institutional analysis, we defined VAI as a positive CSF culture in a patient with ventriculostomy catheter, plus one or more of the following (1) fever recorded >101.5 °F or (2) cerebrospinal fluid (CSF) glucose level, either definition and CDC format seems promising toward facilitating future study and guideline development. Given our strict protocol of sterile catheter placement and care, and our institution's low 2.0% infection rates, we propose an infection-rate target of ≤5 per 1,000 device days. Our results suggest that the use of antibiotics or antibiotic-impregnated catheters is unwarranted--a positive given concerns of evolving anti-microbial resistance.

  20. European dominant position and american monopolization: a unifying approach from basic game theory

    Directory of Open Access Journals (Sweden)

    Pier Luigi Parcu

    2006-06-01

    Full Text Available In this paper we explore the meaning of some fundamental legal definitions of Europeanand American antitrust using basic concepts of game theory. Important definitions in EU law likedominant position of a firm, abuse of such a dominant position, special responsibility of thedominant firm, or in US law like monopoly or monopolization offence, acquire more precisemeaning and operational content. Moreover they look closer than usually contended.In a competition game, in which there is a truly monopolistic/dominant firm (MDF andcompetition law is respected, we state in a formal theorem that an MDF has a dominant strategy, soits choices should never be a source of ex post regret. Other players of the game, understanding andanticipating the realization of this dominant strategy, will optimize their behaviour taking it intoaccount and thus be more able to select a best solution among all possible outcomes.In this context which kind of behaviours can an MDF adopt to defend its market shares andeconomic position? Following the US Supreme Court and EU Court of Justice an MDF mustcompete using normal methods of competition, superior product or business acumen, therefore weargue that market power, whatever its origin, can be defended only through competition on themerit. This definition has practical consequences: unpredictable behaviours and actions that anormal firm would not adopt might be identified as illegal abuses of dominant position ormonopolization offences, also this idea is formalized in a theorem.

  1. Reconstruction of Cluster Positions in the LHCb Velo

    CERN Document Server

    Parkes, C; Szumlak, T

    2007-01-01

    This note describes the `Velo Cluster Position Tool'. This software is used in the GAUDI framework to estimate the hit position of a particle traversing the silicon sensors of the LHCb VELO and to estimate the uncertainty on this position. This estimate and its uncertainty are used in the LHCb track fit. The definition of the cluster centre is given and the baseline linear approximation method presented. The position error is strongly dependent on the angle of incidence of the particle on the silicon sensors measured perpendicularly to the strips -- known as the projected angle -- and on the silicon sensor pitch at the point of incidence, and is parametrised in terms of these variables. Pull plots are presented to show the quality of the current tuning implemented for simulation events.

  2. General operator form of the non-local three-nucleon force

    Energy Technology Data Exchange (ETDEWEB)

    Topolnicki, K. [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland)

    2017-09-15

    This paper describes a procedure to obtain the general form of the three-nucleon force. The result is an operator form where the momentum space matrix element of the three-nucleon potential is written as a linear combination of 320 isospin-spin-momentum operators and scalar functions of momenta. Any spatial and isospin rotation invariant three-nucleon force can be written in this way and in order for the potential to be Hermitian, symmetric under parity inversion, time reversal and particle exchange, the scalar functions must have definite transformation properties under these discrete operations. A complete list of the isospin-spin-momentum operators and scalar function transformation properties is given. (orig.)

  3. 5 CFR 550.153 - Bases for determining positions for which premium pay under § 550.151 is authorized.

    Science.gov (United States)

    2010-01-01

    ... PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Premium Pay Administratively... once a week. (3) There must be a definite basis for anticipating that the irregular or occasional... circumstances must be a definite, official, and special requirement of his position. (2) The employee must...

  4. A New Definition of and Role for Preferences in Positive Economics

    NARCIS (Netherlands)

    Engelen, Bart

    2017-01-01

    Positive economic models aim to provide truthful explanations of significant (aspects of) economic phenomena. While the notion of ‘preferences’ figures prominently in micro-economic models, it suffers from a remarkable lack of conceptual clarity and rigor. After distinguishing narrow homo economicus

  5. Issues and Perspectives in Meditation Research: In Search for a Definition

    Science.gov (United States)

    Awasthi, Bhuvanesh

    2013-01-01

    Despite the growing interest in the neurobiological correlates of meditation, most research has omitted to take into account the underlying philosophical aspects of meditation and its wider implications. This, in turn, is reflected in issues surrounding definition, study design, and outcomes. Here, I highlight the often ignored but important aspect of definition in the existing scholarship on neuroscience and meditation practice. For a satisfactory account of a neuroscience of meditation, we must aim to retrieve an operational definition that is inclusive of a traditional ontological description as well as the modern neurocognitive account of the phenomena. Moving beyond examining the effects of meditation practice, to take a potential step forward in the direction to establish how meditation works, it becomes crucial to appraise the philosophical positions that underlie the phenomenology of meditation in the originating traditions. This endeavor may challenge our intuitions and concepts in either directions, but issues pertaining to definition, design, and validity of response measures are extremely important for the evolution of the field and will provide a much-needed context and framework for meditation based interventions. PMID:23335908

  6. Issues and perspectives in meditation research: in search for a definition.

    Science.gov (United States)

    Awasthi, Bhuvanesh

    2012-01-01

    Despite the growing interest in the neurobiological correlates of meditation, most research has omitted to take into account the underlying philosophical aspects of meditation and its wider implications. This, in turn, is reflected in issues surrounding definition, study design, and outcomes. Here, I highlight the often ignored but important aspect of definition in the existing scholarship on neuroscience and meditation practice. For a satisfactory account of a neuroscience of meditation, we must aim to retrieve an operational definition that is inclusive of a traditional ontological description as well as the modern neurocognitive account of the phenomena. Moving beyond examining the effects of meditation practice, to take a potential step forward in the direction to establish how meditation works, it becomes crucial to appraise the philosophical positions that underlie the phenomenology of meditation in the originating traditions. This endeavor may challenge our intuitions and concepts in either directions, but issues pertaining to definition, design, and validity of response measures are extremely important for the evolution of the field and will provide a much-needed context and framework for meditation based interventions.

  7. Issues and perspectives in meditation research: In search for a definition

    Directory of Open Access Journals (Sweden)

    Bhuvanesh eAwasthi

    2013-01-01

    Full Text Available Despite the growing interest in the neurobiological correlates of meditation, most research has omitted to take into account the underlying philosophical aspects of meditation and its wider implications. This, in turn, is reflected in issues surrounding definition, study design and outcomes. Here, I highlight the often ignored but important aspect of definition in the existing scholarship on neuroscience and meditation practice. For a satisfactory account of a neuroscience of meditation, we must aim to retrieve an operational definition that is inclusive of a traditional ontological description as well as the modern neurocognitive account of the phenomena. Moving beyond examining the effects of meditation practice, to take a potential step forward in the direction to establish how meditation works, it becomes crucial to appraise the philosophical positions that underlie the phenomenology of meditation in the originating traditions. This endeavour may challenge our intuitions and concepts in either directions, but issues pertaining to definition, design and validity of response measures are extremely important for the evolution of the field and will provide a much-needed context and framework for meditation based interventions.

  8. Cross-cultural comparison of successful aging definitions between Chinese and Hmong elders in the United States.

    Science.gov (United States)

    Nguyen, Annie L; Seal, David W

    2014-06-01

    The purpose of the study was to elicit the definitions of successful aging according to Chinese and Hmong elders living in Milwaukee, WI. In-depth semi-structured interviews were conducted with 44 elders (Hmong n = 21 and Chinese n = 23). Findings show some similarities in the Chinese and Hmong elders' definitions though specific cultural differences exist. Chinese elders emphasized physical health and mobility, mental health, positive attitudes, shedding responsibilities, positive family relationships, financial stability, social engagement, religious faith, and accomplishments and volunteer work. Hmong elders emphasized physical health and mobility, mental health, harmonious relationships, positive family relationships, tangible family support, financial stability, social engagement, and religious faith. Cross-cultural comparisons of the findings highlight the cultural heterogeneity between these two subgroups. Implications for practice are discussed.

  9. Claims-Based Definition of Death in Japanese Claims Database: Validity and Implications

    Science.gov (United States)

    Ooba, Nobuhiro; Setoguchi, Soko; Ando, Takashi; Sato, Tsugumichi; Yamaguchi, Takuhiro; Mochizuki, Mayumi; Kubota, Kiyoshi

    2013-01-01

    Background For the pending National Claims Database in Japan, researchers will not have access to death information in the enrollment files. We developed and evaluated a claims-based definition of death. Methodology/Principal Findings We used healthcare claims and enrollment data between January 2005 and August 2009 for 195,193 beneficiaries aged 20 to 74 in 3 private health insurance unions. We developed claims-based definitions of death using discharge or disease status and Charlson comorbidity index (CCI). We calculated sensitivity, specificity and positive predictive values (PPVs) using the enrollment data as a gold standard in the overall population and subgroups divided by demographic and other factors. We also assessed bias and precision in two example studies where an outcome was death. The definition based on the combination of discharge/disease status and CCI provided moderate sensitivity (around 60%) and high specificity (99.99%) and high PPVs (94.8%). In most subgroups, sensitivity of the preferred definition was also around 60% but varied from 28 to 91%. In an example study comparing death rates between two anticancer drug classes, the claims-based definition provided valid and precise hazard ratios (HRs). In another example study comparing two classes of anti-depressants, the HR with the claims-based definition was biased and had lower precision than that with the gold standard definition. Conclusions/Significance The claims-based definitions of death developed in this study had high specificity and PPVs while sensitivity was around 60%. The definitions will be useful in future studies when used with attention to the possible fluctuation of sensitivity in some subpopulations. PMID:23741526

  10. A unified definition of a vortex derived from vortical flow and the resulting pressure minimum

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, K [Department of Mechanical Engineering, Aichi Institute of Technology, Toyota, Aichi 470–0392 (Japan); Sugiyama, K; Takagi, S, E-mail: nakayama@aitech.ac.jp, E-mail: kazuyasu.sugiyama@riken.jp, E-mail: takagi@mech.t.u-tokyo.ac.jp [Department of Mechanical Engineering, School of Engineering, The University of Tokyo, Hongo, Tokyo 113–8656 (Japan)

    2014-10-01

    This paper presents a novel definition of a vortex that integrates the concepts of the invariant swirling motion, the pressure minimum characteristics induced by the swirling motion and the positive Laplacian of the pressure. The current definition specifies a vortex that has a swirling motion and resulting pressure minimum feature in the swirl plane, which is simply represented by the eigenvalues and eigenvectors of the velocity gradient tensor. (paper)

  11. The definite article in Romance expletives and long weak definites

    Directory of Open Access Journals (Sweden)

    M.Teresa Espinal

    2017-03-01

    Full Text Available This paper focuses on some issues involving expletive articles and long weak definites in Romance (mainly Spanish, Brazilian Portuguese and Catalan, in comparison to DPs that elicit a strong reading. We show the similarities between expletive definites and long weak definites, and we argue for an analysis in common to other polarity items in terms of polarity sensitivity. We reach the conclusion that the definite article in Romance comes in two variants: the referentially unique variant (to be translated as the semantic 'iota 'operator and the polar variant, formally characterized with an abstract [+σ] feature, that encodes a weak bound reading (to be semantically translated by an existential operator.

  12. MAY THE HIGH-DEGREE SATISFYING UNREASONABLE REQUIREMENT ALSO MEANS THE GOOD QUALITY: FIVE BIG FLAWS IN THE SUBJECTIVE DEFINITION OF QUALITY AND THEIR SOLUTION

    Directory of Open Access Journals (Sweden)

    Runsheng Tu

    2011-06-01

    Full Text Available J. M. Juran's subjective quality definition of "quality is degree to which a set of inherent characteristics fulfils requirements" and the account have five big inherent problems: "to disturb the language order", "to violate the objective of the standardized work", "the dependence to the subjective being too strong, to disobey the objectivity principle", "to be short of the enthusiastic limit", "to be possible to reduce the requirement through the reduction, to improve the quality", "to be possible provides the reason theoretically for the fake and shoddy manufacturer and the person whose quality is bad", "to have the suspicion of circular definition". The method to treat the wound is establishing the definition of "quality is the positive degree". This definition of quality both has guaranteed the positive connotation of J. M. Juran's quality definition and has cured the flaws of J. M. Juran's quality definition, but also has promulgated the condition of the symmetry and the connection between quality and value.

  13. Dynamic Target Definition: A novel approach for PTV definition in ion beam therapy

    International Nuclear Information System (INIS)

    Cabal, Gonzalo A.; Jäkel, Oliver

    2013-01-01

    Purpose: To present a beam arrangement specific approach for PTV definition in ion beam therapy. Materials and methods: By means of a Monte Carlo error propagation analysis a criteria is formulated to assess whether a voxel is safely treated. Based on this a non-isotropical expansion rule is proposed aiming to minimize the impact of uncertainties on the dose delivered. Results: The method is exemplified in two cases: a Head and Neck case and a Prostate case. In both cases the modality used is proton beam irradiation and the sources of uncertainties taken into account are positioning (set up) errors and range uncertainties. It is shown how different beam arrangements have an impact on plan robustness which leads to different target expansions necessary to assure a predefined level of plan robustness. The relevance of appropriate beam angle arrangements as a way to minimize uncertainties is demonstrated. Conclusions: A novel method for PTV definition in on beam therapy is presented. The method show promising results by improving the probability of correct dose CTV coverage while reducing the size of the PTV volume. In a clinical scenario this translates into an enhanced tumor control probability while reducing the volume of healthy tissue being irradiated

  14. On Positive Semidefinite Modification Schemes for Incomplete Cholesky Factorization

    Czech Academy of Sciences Publication Activity Database

    Scott, J.; Tůma, Miroslav

    2014-01-01

    Roč. 36, č. 2 (2014), A609-A633 ISSN 1064-8275 R&D Projects: GA ČR GA13-06684S Institutional support: RVO:67985807 Keywords : sparse matrices * sparse linear systems * positive-definite symmetric systems * iterative solvers * preconditioning * incomplete Cholesky factorization Subject RIV: BA - General Mathematics Impact factor: 1.854, year: 2014

  15. Goal Definition

    DEFF Research Database (Denmark)

    Bjørn, Anders; Laurent, Alexis; Owsianiak, Mikołaj

    2018-01-01

    The goal definition is the first phase of an LCA and determines the purpose of a study in detail. This chapter teaches how to perform the six aspects of a goal definition: (1) Intended applications of the results, (2) Limitations due to methodological choices, (3) Decision context and reasons...... for carrying out the study, (4) Target audience , (5) Comparative studies to be disclosed to the public and (6) Commissioner of the study and other influential actors. The instructions address both the conduct and reporting of a goal definition and are largely based on the ILCD guidance document (EC...

  16. Evaluation of a surveillance case definition for anogenital warts, Kaiser Permanente northwest.

    Science.gov (United States)

    Naleway, Allison L; Weinmann, Sheila; Crane, Brad; Gee, Julianne; Markowitz, Lauri E; Dunne, Eileen F

    2014-08-01

    Most studies of anogenital wart (AGW) epidemiology have used large clinical or administrative databases and unconfirmed case definitions based on combinations of diagnosis and procedure codes. We developed and validated an AGW case definition using a combination of diagnosis codes and other information available in the electronic medical record (provider type, laboratory testing). We calculated the positive predictive value (PPV) of this case definition compared with manual medical record review in a random sample of 250 cases. Using this case definition, we calculated the annual age- and sex-stratified prevalence of AGW among individuals 11 through 30 years of age from 2000 through 2005. We identified 2730 individuals who met the case definition. The PPV of the case definition was 82%, and the average annual prevalence was 4.16 per 1000. Prevalence of AGW was higher in females compared with males in every age group, with the exception of the 27- to 30-year-olds. Among females, prevalence peaked in the 19- to 22-year-olds, and among males, the peak was observed in 23- to 26-year-olds. The case definition developed in this study is the first to be validated with medical record review and has a good PPV for the detection of AGW. The prevalence rates observed in this study were higher than other published rates, but the age- and sex-specific patterns observed were consistent with previous reports.

  17. Positive psychiatry: its time has come.

    Science.gov (United States)

    Jeste, Dilip V; Palmer, Barton W; Rettew, David C; Boardman, Samantha

    2015-06-01

    Traditionally, psychiatry has been defined and practiced as a branch of medicine focused on the diagnosis and treatment of mental illnesses. Based on growing empirical evidence, we believe that this definition warrants expansion to include the concept of positive psychiatry. In the present article, we provide a critical overview of this emerging field and a select review of relevant scientific literature. Positive psychiatry may be defined as the science and practice of psychiatry that seeks to understand and promote well-being through assessment and interventions involving positive psychosocial characteristics (PPCs) in people who suffer from or are at high risk of developing mental or physical illnesses. It can also benefit nonclinical populations. Positive psychiatry has 4 main components: (1) positive mental health outcomes (eg, well-being), (2) PPCs that comprise psychological traits (resilience, optimism, personal mastery and coping self-efficacy, social engagement, spirituality and religiosity, and wisdom-including compassion) and environmental factors (family dynamics, social support, and other environmental determinants of overall health), (3) biology of positive psychiatry constructs, and (4) positive psychiatry interventions including preventive ones. There are promising empirical data to suggest that positive traits may be improved through psychosocial and biological interventions. As a branch of medicine rooted in biology, psychiatry, especially with the proposed conceptualization of positive psychiatry, is well poised to provide major contributions to the positive mental health movement, thereby impacting the overall health care of the population. © Copyright 2015 Physicians Postgraduate Press, Inc.

  18. Positive Psychiatry: Its Time Has Come

    Science.gov (United States)

    Jeste, Dilip V.; Palmer, Barton W.; Rettew, David C.; Boardman, Samantha

    2017-01-01

    Traditionally, psychiatry has been defined and practiced as a branch of medicine focused on the diagnosis and treatment of mental illnesses. Based on growing empirical evidence, we believe that this definition warrants expansion to include the concept of positive psychiatry. In the present article we provide a critical overview of this emerging field and a select review of relevant scientific literature. Positive psychiatry may be defined as the science and practice of psychiatry that seeks to understand and promote well-being through assessment and interventions involving positive psychosocial characteristics (PPCs) in people who suffer from or are at high risk of developing mental or physical illnesses. It can also benefit non-clinical populations. Positive psychiatry has 4 main components: (1) positive mental health outcomes (e.g., well-being), (2) PPCs that comprise psychological traits (resilience, optimism, personal mastery and coping self-efficacy, social engagement, spirituality and religiosity, and wisdom - including compassion) and environmental factors (family dynamics, social support, and other environmental determinants of overall health), (3) biology of positive psychiatry constructs, and (4) positive psychiatry Interventions including preventive ones. There are promising empirical data to suggest that positive traits may be improved through psychosocial and biological interventions. As a branch of medicine, rooted in biology, psychiatry, especially with the proposed conceptualization of positive psychiatry, is well poised to provide major contributions to the positive mental health movement, thereby impacting the overall healthcare of the population. PMID:26132670

  19. 16 CFR 316.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... or general partnership, corporation, or other business entity. (i) The definition of the term... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Definitions. 316.2 Section 316.2 Commercial... Definitions. (a) The definition of the term “affirmative consent” is the same as the definition of that term...

  20. Exponential rarefaction of real curves with many components

    OpenAIRE

    Gayet , Damien; Welschinger , Jean-Yves

    2011-01-01

    21 pages; Given a positive real Hermitian holomorphic line bundle L over a smooth real projective manifold X, the space of real holomorphic sections of the bundle L^d inherits for every positive integer d a L^2 scalar product which induces a Gaussian measure. When X is a curve or a surface, we estimate the volume of the cone of real sections whose vanishing locus contains many real components. In particular, the volume of the cone of maximal real sections decreases exponentially as d grows to...

  1. Low-lying eigenmodes of the Wilson-Dirac operator and correlations with topological objects

    International Nuclear Information System (INIS)

    Kusterer, Daniel-Jens; Hedditch, John; Kamleh, Waseem; Leinweber, D.B.; Williams, Anthony G.

    2002-01-01

    The probability density of low-lying eigenvectors of the hermitian Wilson-Dirac operator H(κ)=γ 5 D W (κ) is examined. Comparisons in position and size between eigenvectors, topological charge and action density are made. We do this for standard Monte-Carlo generated SU(3) background fields and for single instanton background fields. Both hot and cooled SU(3) background fields are considered. An instanton model is fitted to eigenmodes and topological charge density and the sizes and positions of these are compared

  2. The position of Ghana on the progressive map of positive mental health: A critical perspective.

    Science.gov (United States)

    Wilson, Angelina; Somhlaba, Nceba Z

    2017-05-01

    According to the World Health Organisation (WHO), mental health is a state of well-being and not just the absence of diseases. With this definition, there has been a surge of mental health research, albeit still predominantly in Western countries, which is reflected in contemporary theories on positive mental health that include 'flourishing mental health', 'salutogenesis', and 'fortigenesis'. However, in low- and middle-income countries (LMICs), mental health research is slowly receiving scholarly attention. The aim of this paper was twofold: Firstly, to highlight progress that had been made in some LMICs, giving consideration to research across different settings and populations as a basis to argue for more research on positive mental health in the Ghanaian context. Secondly, to present a critical perspective on the current mental health research trends in Ghana, thus discussing important recommendations for future research.

  3. Complex Algebraic Varieties

    CERN Document Server

    Peternell, Thomas; Schneider, Michael; Schreyer, Frank-Olaf

    1992-01-01

    The Bayreuth meeting on "Complex Algebraic Varieties" focussed on the classification of algebraic varieties and topics such as vector bundles, Hodge theory and hermitian differential geometry. Most of the articles in this volume are closely related to talks given at the conference: all are original, fully refereed research articles. CONTENTS: A. Beauville: Annulation du H(1) pour les fibres en droites plats.- M. Beltrametti, A.J. Sommese, J.A. Wisniewski: Results on varieties with many lines and their applications to adjunction theory.- G. Bohnhorst, H. Spindler: The stability of certain vector bundles on P(n) .- F. Catanese, F. Tovena: Vector bundles, linear systems and extensions of (1).- O. Debarre: Vers uns stratification de l'espace des modules des varietes abeliennes principalement polarisees.- J.P. Demailly: Singular hermitian metrics on positive line bundles.- T. Fujita: On adjoint bundles of ample vector bundles.- Y. Kawamata: Moderate degenerations of algebraic surfaces.- U. Persson: Genus two fibra...

  4. Giving up the ghost

    International Nuclear Information System (INIS)

    Bender, Carl M; Mannheim, Philip D

    2008-01-01

    The Pais-Uhlenbeck model is a quantum theory described by a higher-derivative field equation. It has been believed for many years that this model possesses ghost states (quantum states of negative norm) and therefore that this model is a physically unacceptable quantum theory. The existence of such ghost states was believed to be attributable to the field equation having more than two derivatives. This paper shows that the Pais-Uhlenbeck model does not possess any ghost states at all and that it is a perfectly acceptable quantum theory. The supposed ghost states in this model arise if the Hamiltonian of the model is (incorrectly) treated as being Dirac Hermitian (invariant under combined matrix transposition and complex conjugation). However, the Hamiltonian is not Dirac Hermitian, but rather it is PT symmetric. When it is quantized correctly according to the rules of PT quantum mechanics, the energy spectrum is real and bounded below and all of the quantum states have positive norm

  5. Integrating positive psychology into health-related quality of life research.

    Science.gov (United States)

    Park, Crystal L

    2015-07-01

    Positive psychology is an increasingly influential force in theory and research within psychology and many related fields, including behavioral medicine, sociology, and public health. This article aims to review the ways in which positive psychology and health-related quality of life (HRQOL) research currently interface and to suggest fruitful future directions. This article reviews the basic elements of positive psychology and provides an overview of conceptual and empirical links between positive psychology and HRQOL. The role of one central aspect of positive psychology (meaning) within HRQOL is highlighted, and unresolved issues (e.g., lack of definitional clarity) are discussed. Some research on HRQOL has taken a positive psychology perspective, demonstrating the usefulness of taking a positive psychology approach. However, many areas await integration. Once conceptual and methodological issues are resolved, positive psychology may profitably inform many aspects of HRQOL research and, perhaps, clinical interventions to promote HRQOL as well.

  6. Clinical relevance of positive voltage-gated potassium channel (VGKC)-complex antibodies: experience from a tertiary referral centre.

    Science.gov (United States)

    Paterson, Ross W; Zandi, Michael S; Armstrong, Richard; Vincent, Angela; Schott, Jonathan M

    2014-06-01

    Voltage-gated potassium channel (VGKC)-complex antibodies can be associated with a range of immunotherapy-responsive clinical presentations including limbic encephalitis, Morvan's syndrome and acquired neuromyotonia. However, there are patients with positive levels in whom the significance is uncertain. To evaluate the clinical significance associated with positive (>100 pM) VGKC-complex antibodies. Over a 4-year period, 1053 samples were sent for testing of which 55 were positive. The clinical presentations, final diagnoses and responses to immunotherapies, when given, were assessed retrospectively and the likelihood of autoimmunity was categorised as definite, possible, unlikely or undetermined (modified from Zuliani et al 2012). Only 4 of the 32 patients with low-positive (100-400 pM) levels were considered definitely autoimmune, 3 with peripheral nerve hyperexcitability and 1 with a thymoma; 3 were given immunotherapies. Of the remaining 28 with low-positive levels, 13 (3 of whom had tumours) were considered possibly autoimmune, and 15 were unlikely or undetermined; 1 was given immunotherapy unsuccessfully. Of the 23 patients with high-positive (>400 pM) levels, 12 were given immunotherapies, 11 of whom showed a good response. 11 were considered definitely autoimmune, 10 with limbic encephalitis (antibody specificity: 5 LGI1, 1 contactin2, 2 negative, 2 untested) and 1 with a tumour. In the remaining 12, autoimmunity was considered possible (n=9; most had not received immunotherapies), or unlikely (n=3). As antibody testing becomes more widely available, and many samples are referred from patients with less clear-cut diagnoses, it is important to assess the utility of the results. VGKC-complex antibodies in the range of 100-400 pM (0.1-0.4 nM) were considered clinically relevant in rare conditions with peripheral nerve hyperexcitability and appeared to associate with tumours (12.5%). By contrast high-positive (>400 pM; >0.4 nM) levels were considered definitely

  7. Wind turbines and health: An examination of a proposed case definition.

    Science.gov (United States)

    McCunney, Robert J; Morfeld, Peter; Colby, W David; Mundt, Kenneth A

    2015-01-01

    Renewable energy demands have increased the need for new wind farms. In turn, concerns have been raised about potential adverse health effects on nearby residents. A case definition has been proposed to diagnose "Adverse Health Effects in the Environs of Industrial Wind Turbines" (AHE/IWT); initially in 2011 and then with an update in 2014. The authors invited commentary and in turn, we assessed its scientific merits by quantitatively evaluating its proposed application. We used binomial coefficients to quantitatively assess the potential of obtaining a diagnosis of AHE/IWT. We also reviewed the methodology and process of the development of the case definition by contrasting it with guidelines on case definition criteria of the USA Institute of Medicine. The case definition allows at least 3,264 and up to 400,000 possibilities for meeting second- and third-order criteria, once the limited first-order criteria are met. IOM guidelines for clinical case definitions were not followed. The case definition has virtually no specificity and lacks scientific support from peer-reviewed literature. If applied as proposed, its application will lead to substantial potential for false-positive assessments and missed diagnoses. Virtually any new illness that develops or any prevalent illness that worsens after the installation of wind turbines within 10 km of a residence could be considered AHE/IWT if the patient feels better away from home. The use of this case definition in the absence of a thorough medical evaluation with appropriate diagnostic studies poses risks to patients in that treatable disorders would be overlooked. The case definition has significant potential to mislead patients and its use cannot be recommended for application in any health-care or decision-making setting.

  8. Wind turbines and health: An examination of a proposed case definition

    Directory of Open Access Journals (Sweden)

    Robert J McCunney

    2015-01-01

    Full Text Available Renewable energy demands have increased the need for new wind farms. In turn, concerns have been raised about potential adverse health effects on nearby residents. A case definition has been proposed to diagnose "Adverse Health Effects in the Environs of Industrial Wind Turbines" (AHE/IWT; initially in 2011 and then with an update in 2014. The authors invited commentary and in turn, we assessed its scientific merits by quantitatively evaluating its proposed application. We used binomial coefficients to quantitatively assess the potential of obtaining a diagnosis of AHE/IWT. We also reviewed the methodology and process of the development of the case definition by contrasting it with guidelines on case definition criteria of the USA Institute of Medicine. The case definition allows at least 3,264 and up to 400,000 possibilities for meeting second- and third-order criteria, once the limited first-order criteria are met. IOM guidelines for clinical case definitions were not followed. The case definition has virtually no specificity and lacks scientific support from peer-reviewed literature. If applied as proposed, its application will lead to substantial potential for false-positive assessments and missed diagnoses. Virtually any new illness that develops or any prevalent illness that worsens after the installation of wind turbines within 10 km of a residence could be considered AHE/IWT if the patient feels better away from home. The use of this case definition in the absence of a thorough medical evaluation with appropriate diagnostic studies poses risks to patients in that treatable disorders would be overlooked. The case definition has significant potential to mislead patients and its use cannot be recommended for application in any health-care or decision-making setting

  9. Wind turbines and health: An examination of a proposed case definition

    Science.gov (United States)

    McCunney, Robert J.; Morfeld, Peter; Colby, W. David; Mundt, Kenneth A.

    2015-01-01

    Renewable energy demands have increased the need for new wind farms. In turn, concerns have been raised about potential adverse health effects on nearby residents. A case definition has been proposed to diagnose “Adverse Health Effects in the Environs of Industrial Wind Turbines” (AHE/IWT); initially in 2011 and then with an update in 2014. The authors invited commentary and in turn, we assessed its scientific merits by quantitatively evaluating its proposed application. We used binomial coefficients to quantitatively assess the potential of obtaining a diagnosis of AHE/IWT. We also reviewed the methodology and process of the development of the case definition by contrasting it with guidelines on case definition criteria of the USA Institute of Medicine. The case definition allows at least 3,264 and up to 400,000 possibilities for meeting second- and third-order criteria, once the limited first-order criteria are met. IOM guidelines for clinical case definitions were not followed. The case definition has virtually no specificity and lacks scientific support from peer-reviewed literature. If applied as proposed, its application will lead to substantial potential for false-positive assessments and missed diagnoses. Virtually any new illness that develops or any prevalent illness that worsens after the installation of wind turbines within 10 km of a residence could be considered AHE/IWT if the patient feels better away from home. The use of this case definition in the absence of a thorough medical evaluation with appropriate diagnostic studies poses risks to patients in that treatable disorders would be overlooked. The case definition has significant potential to mislead patients and its use cannot be recommended for application in any health-care or decision-making setting. PMID:26168947

  10. PSA bounces after neoadjuvant androgen deprivation and external beam radiation: Impact on definitions of failure

    International Nuclear Information System (INIS)

    Zietman, Anthony L.; Christodouleas, John P.; Shipley, William U.

    2005-01-01

    Purpose: To determine the characteristics of prostate specific antigen (PSA) bounces after external beam radiation therapy (EBRT) with neoadjuvant androgen deprivation and their impact on definitions of biochemical failure. Methods and Materials: Characteristics of bounce were calculated for all patients treated by EBRT with neoadjuvant androgen deprivation at our institution between 1992 and 1998 (preexclusion analysis). Calculations were repeated for the subgroup that satisfied additional inclusion/exclusion criteria (postexclusion analysis). The percentage of bounces scoring as false positives according to the ASTRO definition of biochemical failure was compared with those for three alternative definitions (Vancouver, Nadir-plus-two, and Nadir-plus-three) using McNemar's tests. Results: Thirty-nine percent (preexclusion cohort) and 56% (postexclusion cohort) of patients demonstrated a PSA bounce. Twenty percent (preexclusion analysis) and 25% (postexclusion analysis) of these bounces scored as biochemical failure according to the ASTRO definition. The Nadir-plus-three definition scored the smallest percentage of bounces as failure, but the difference between this definition and the ASTRO definition reached statistical significance in neither preexclusion nor postexclusion analyses (p ≥ 0.070). Conclusions: A substantial proportion of patients treated by EBRT with neoadjuvant deprivation experienced a PSA bounce. A large percentage of these bounces scored as biochemical failure according to the ASTRO definition. The Nadir-plus-three definition is less vulnerable to this bias

  11. The theory behind the age-related positivity effect

    Directory of Open Access Journals (Sweden)

    Andrew E Reed

    2012-09-01

    Full Text Available The positivity effect refers to an age-related trend that favors positive over negative stimuli in cognitive processing. Relative to their younger counterparts, older people attend to and remember more positive than negative information. Since the effect was initially identified and the conceptual basis articulated (Mather & Carstensen, 2005 scores of independent replications and related findings have appeared in the literature. Over the same period, a number of investigations have failed to observe age differences in the cognitive processing of emotional material. When findings are considered in theoretical context, a reliable pattern of evidence emerges that helps to refine conceptual tenets. In this article we articulate the operational definition and theoretical foundations of the positivity effect and review the empirical evidence based on studies of visual attention, memory, decision-making, and neural activation. We conclude with a discussion of future research directions with emphasis on the conditions where a focus on positive information may benefit and/or impair cognitive performance in older people.

  12. Psychiatry, religion, positive emotions and spirituality.

    Science.gov (United States)

    Vaillant, George E

    2013-12-01

    This paper proposes that eight positive emotions: awe, love/attachment, trust/faith, compassion, gratitude, forgiveness, joy and hope constitute what we mean by spirituality. These emotions have been grossly ignored by psychiatry. The two sciences that I shall employ to demonstrate this definition of spirituality will be ethology and neuroscience. They are both very new. I will argue that spirituality is not about ideas, sacred texts and theology. Rather, spirituality is all about emotion and social connection that are more dependent on the limbic system than the cortex. Specific religions, for all their limitations, are often the portal through which positive emotions are brought into conscious attention. Neither Freud nor psychiatric textbooks ever mention emotions like joy and gratitude. Hymns and psalms give these emotions pride of place. Our whole concept of psychotherapy might change, if clinicians set about enhancing positive emotions, rather than focusing only on the negative ones. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Comment on 'Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential' [J. Math. Phys. 48, 073515 (2007)

    International Nuclear Information System (INIS)

    Castro, L. B.; Castro, A. S. de

    2010-01-01

    It is shown that the paper 'Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential' by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that does require Hermitian Hamiltonians.

  14. Inter- and intra-observer variation in soft-tissue sarcoma target definition.

    Science.gov (United States)

    Roberge, D; Skamene, T; Turcotte, R E; Powell, T; Saran, N; Freeman, C

    2011-08-01

    To evaluate inter- and intra-observer variability in gross tumor volume definition for adult limb/trunk soft tissue sarcomas. Imaging studies of 15 patients previously treated with preoperative radiation were used in this study. Five physicians (radiation oncologists, orthopedic surgeons and a musculoskeletal radiologist) were asked to contour each of the 15 tumors on T1-weighted, gadolinium-enhanced magnetic resonance images. These contours were drawn twice by each physician. The volume and center of mass coordinates for each gross tumor volume were extracted and a Boolean analysis was performed to measure the degree of volume overlap. The median standard deviation in gross tumor volumes across observers was 6.1% of the average volume (range: 1.8%-24.9%). There was remarkably little variation in the 3D position of the gross tumor volume center of mass. For the 15 patients, the standard deviation of the 3D distance between centers of mass ranged from 0.06 mm to 1.7 mm (median 0.1mm). Boolean analysis demonstrated that 53% to 90% of the gross tumor volume was common to all observers (median overlap: 79%). The standard deviation in gross tumor volumes on repeat contouring was 4.8% (range: 0.1-14.4%) with a standard deviation change in the position of the center of mass of 0.4mm (range: 0mm-2.6mm) and a median overlap of 93% (range: 73%-98%). Although significant inter-observer differences were seen in gross tumor volume definition of adult soft-tissue sarcoma, the center of mass of these volumes was remarkably consistent. Variations in volume definition did not correlate with tumor size. Radiation oncologists should not hesitate to review their contours with a colleague (surgeon, radiologist or fellow radiation oncologist) to ensure that they are not outliers in sarcoma gross tumor volume definition. Protocols should take into account variations in volume definition when considering tighter clinical target volumes. Copyright © 2011 Société française de radioth

  15. Railing for safety: job demands, job control, and safety citizenship role definition.

    Science.gov (United States)

    Turner, Nick; Chmiel, Nik; Walls, Melanie

    2005-10-01

    This study investigated job demands and job control as predictors of safety citizenship role definition, that is, employees' role orientation toward improving workplace safety. Data from a survey of 334 trackside workers were framed in the context of R. A. Karasek's (1979) job demands-control model. High job demands were negatively related to safety citizenship role definition, whereas high job control was positively related to this construct. Safety citizenship role definition of employees with high job control was buffered from the influence of high job demands, unlike that of employees with low job control, for whom high job demands were related to lower levels of the construct. Employees facing both high job demands and low job control were less likely than other employees to view improving safety as part of their role orientation. Copyright (c) 2005 APA, all rights reserved.

  16. Weyl tensors for asymmetric complex curvatures

    International Nuclear Information System (INIS)

    Oliveira, C.G.

    Considering a second rank Hermitian field tensor and a general Hermitian connection the associated complex curvature tensor is constructed. The Weyl tensor that corresponds to this complex curvature is determined. The formalism is applied to the Weyl unitary field theory and to the Moffat gravitational theory. (Author) [pt

  17. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    September 2009, pages 215-626a. Non-Hermitian Hamiltonians in Quantum Physics - Part II ... Entanglement in non-Hermitian quantum theory · Arun K Pati · More Details Abstract ... Minimal classical communication and measurement complexity for quantum information splitting of a two-qubit state · Prasanta K Panigrahi ...

  18. Will the right Robin patient rise, please? Definitions and criteria during management of Robin sequence patients in the Netherlands and Belgium.

    Science.gov (United States)

    Basart, Hanneke; Kruisinga, Frea H; Breugem, Corstiaan C; Don Griot, J Peter W; Hennekam, Raoul C; Van der Horst, Chantal M A M

    2015-01-01

    Robin Sequence (RS) is characterized by micrognathia and upper airway obstruction (UAO), with or without cleft palate, causing respiratory and feeding problems. Management options are: positioning; nasopharyngeal airway (NPA); tongue-lip adhesion (TLA); mandibular distraction (MDO); and tracheostomy. Controversy exists in literature regarding RS definition and management. Here we describe definitions, management strategies and criteria in opting for management strategies, used by Dutch and Belgian cleft teams. A specifically designed questionnaire was sent to members of all 16 Dutch and Belgian cleft teams. 14 cleft teams returned 35 questionnaires. All used micrognathia as definition criterion, 93.4% cleft palate, 51.5%glossoptosis and 45.7% UAO. Six different RS definitions were used; even within a single team >1 definition was used. All teams used different management strategies: all used positioning, 10 NPA, 6 TLA, 7 MDO, 8 tracheostomy, 5 refer patients with invasive treatment indication. Criteria in opting management modalities were: O2-saturation (89.3%), clinical presentation (86.2%), growth and feeding problems (69.0%), polysomnography (62.1%), and differed within teams. The Dutch and Belgian cleft teams use variable RS definitions, different management modalities and criteria in choosing management strategies. A single, strict definition and evidence-based management guidelines should be formulated for optimal patient care. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  19. Automatic positioning control device for automatic control rod exchanger

    International Nuclear Information System (INIS)

    Nasu, Seiji; Sasaki, Masayoshi.

    1982-01-01

    Purpose: To attain accurate positioning for a control rod exchanger. Constitution: The present position for an automatic control rod exchanger is detected by a synchro generator. An aimed stopping position for the exchanger, a stop instruction range depending on the distantial operation delay in the control system and the inertia-running distance of the mechanical system, and a coincidence confirmation range depending on the required positioning accuracy are previously set. If there is a difference between the present position and the aimed stopping position, the automatic exchanger is caused to run toward the aimed stopping position. A stop instruction is generated upon arrival at the position within said stop instruction range, and a coincidence confirmation signal is generated upon arrival at the position within the coincidence confirmation range. Since uncertain factors such as operation delay in the control system and the inertia-running distance of the mechanical system that influence the positioning accuracy are made definite by the method of actual measurement or the like and the stop instruction range and the coincidence confirmation range are set based on the measured data, the accuracy for the positioning can be improved. (Ikeda, J.)

  20. Crossing rule for a PT-symmetric two-level time-periodic system

    International Nuclear Information System (INIS)

    Moiseyev, Nimrod

    2011-01-01

    For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

  1. 48 CFR 2402.101 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... GENERAL DEFINITIONS OF WORDS AND TERMS Definitions 2402.101 Definitions. Accounting Office means the Office of Accounting Operations within the Office of the Chief Financial Officer and includes that Office... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Definitions. 2402.101...

  2. Dimensionality reduction based on distance preservation to local mean for symmetric positive definite matrices and its application in brain-computer interfaces

    Science.gov (United States)

    Davoudi, Alireza; Shiry Ghidary, Saeed; Sadatnejad, Khadijeh

    2017-06-01

    Objective. In this paper, we propose a nonlinear dimensionality reduction algorithm for the manifold of symmetric positive definite (SPD) matrices that considers the geometry of SPD matrices and provides a low-dimensional representation of the manifold with high class discrimination in a supervised or unsupervised manner. Approach. The proposed algorithm tries to preserve the local structure of the data by preserving distances to local means (DPLM) and also provides an implicit projection matrix. DPLM is linear in terms of the number of training samples. Main results. We performed several experiments on the multi-class dataset IIa from BCI competition IV and two other datasets from BCI competition III including datasets IIIa and IVa. The results show that our approach as dimensionality reduction technique—leads to superior results in comparison with other competitors in the related literature because of its robustness against outliers and the way it preserves the local geometry of the data. Significance. The experiments confirm that the combination of DPLM with filter geodesic minimum distance to mean as the classifier leads to superior performance compared with the state of the art on brain-computer interface competition IV dataset IIa. Also the statistical analysis shows that our dimensionality reduction method performs significantly better than its competitors.

  3. 5 CFR 316.702 - Excepted positions brought into the competitive service.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Excepted positions brought into the competitive service. 316.702 Section 316.702 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL... provisions of § 316.402. (d) An employee who was serving under an excepted appointment with a definite time...

  4. Hermiticity and gauge invariance

    International Nuclear Information System (INIS)

    Treder, H.J.

    1987-01-01

    In the Theory of Hermitian Relativity (HRT) the postulates of hermiticity and gauge invariance are formulated in different ways, due to a different understanding of the idea of hermiticity. However all hermitian systems of equations have to satisfy Einstein's weak system of equations being equivalent to Einstein-Schroedinger equations. (author)

  5. Principal minors and rhombus tilings

    International Nuclear Information System (INIS)

    Kenyon, Richard; Pemantle, Robin

    2014-01-01

    The algebraic relations between the principal minors of a generic n × n matrix are somewhat mysterious, see e.g. Lin and Sturmfels (2009 J. Algebra 322 4121–31). We show, however, that by adding in certain almost principal minors, the ideal of relations is generated by translations of a single relation, the so-called hexahedron relation, which is a composition of six cluster mutations. We give in particular a Laurent-polynomial parameterization of the space of n × n matrices, whose parameters consist of certain principal and almost principal minors. The parameters naturally live on vertices and faces of the tiles in a rhombus tiling of a convex 2n-gon. A matrix is associated to an equivalence class of tilings, all related to each other by Yang–Baxter-like transformations. By specializing the initial data we can similarly parameterize the space of Hermitian symmetric matrices over R,C or H the quaternions. Moreover by further specialization we can parametrize the space of positive definite matrices over these rings. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Cluster algebras mathematical physics’. (paper)

  6. Impulse position control algorithms for nonlinear systems

    Energy Technology Data Exchange (ETDEWEB)

    Sesekin, A. N., E-mail: sesekin@list.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002 (Russian Federation); Institute of Mathematics and Mechanics, Ural Division of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation); Nepp, A. N., E-mail: anepp@urfu.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002 (Russian Federation)

    2015-11-30

    The article is devoted to the formalization and description of impulse-sliding regime in nonlinear dynamical systems that arise in the application of impulse position controls of a special kind. The concept of trajectory impulse-sliding regime formalized as some limiting network element Euler polygons generated by a discrete approximation of the impulse position control This paper differs from the previously published papers in that it uses a definition of solutions of systems with impulse controls, it based on the closure of the set of smooth solutions in the space of functions of bounded variation. The need for the study of such regimes is the fact that they often arise when parry disturbances acting on technical or economic control system.

  7. Impulse position control algorithms for nonlinear systems

    Science.gov (United States)

    Sesekin, A. N.; Nepp, A. N.

    2015-11-01

    The article is devoted to the formalization and description of impulse-sliding regime in nonlinear dynamical systems that arise in the application of impulse position controls of a special kind. The concept of trajectory impulse-sliding regime formalized as some limiting network element Euler polygons generated by a discrete approximation of the impulse position control This paper differs from the previously published papers in that it uses a definition of solutions of systems with impulse controls, it based on the closure of the set of smooth solutions in the space of functions of bounded variation. The need for the study of such regimes is the fact that they often arise when parry disturbances acting on technical or economic control system.

  8. An evaluation of modified case definitions for the detection of dengue hemorrhagic fever. Puerto Rico Association of Epidemiologists.

    Science.gov (United States)

    Rigau-Pérez, J G; Bonilla, G L

    1999-12-01

    The case definition for dengue hemorrhagic fever (DHF) requires fever, platelets plasma leakage evidenced by hemoconcentration > or = 20%, pleural or abdominal effusions, hypoproteinemia or hypoalbuminemia. We evaluated the specificity and yield of modified DHF case definitions and the recently proposed World Health Organization criteria for a provisional diagnosis of DHF, using a data base of laboratory-positive and laboratory-negative reports of hospitalizations for suspected dengue in Puerto Rico, 1994 to 1996. By design, all modifications had 100% sensitivity. More liberal criteria for plasma leakage were examined: 1) adding as evidence a single hematocrit > or = 50% (specificity 97.4%); 2) accepting hemoconcentration > or = 10% (specificity 90.1%); and 3) accepting either hematocrit > or = 50% or hemoconcentration > or = 10% (specificity 88.8%). The new DHF cases identified by these definitions (and percent laboratory positive) were 25 (100.0%), 95 (90.5%), and 107 (91.6%), respectively. In contrast, the provisional diagnosis of DHF (fever and hemorrhage, and one or more of platelets or = 20%, or at least a rising hematocrit [redefined quantitatively as a 5% or greater relative change]) showed a specificity of 66.8%, and identified 318 new DHF cases, of which 282 (88.7%) were laboratory-positive. Very small changes in the criteria may result in a large number of new cases. The modification that accepted either hematocrit > or = 50% or hemoconcentration > or = 10% had acceptable specificity, while doubling the detection of DHF-compatible, laboratory-positive severe cases, but "provisional diagnosis" showed even lower specificity, and may produce inflated DHF incidence figures. Modified case definitions should be prospectively evaluated with patients in a health-care facility before they are recommended for widespread use.

  9. The product form for path integrals on curved manifolds

    Science.gov (United States)

    Grosche, C.

    1988-03-01

    A general and simple framework for treating path integrals on curved manifolds is presented. The crucial point will be a product ansatz for the metric tensor and the quantum hamiltonian, i.e. we shall write g αβ = h αγh βγ and H = (1/2m)h αγp αp βh βγ + V + ΔV , respectively, a prescription which we shall call “product form” definition. The p α are hermitian momenta and Δ V is a well-defined quantum correction. We shall show that this ansatz, which looks quite special, is in fact - under reasonable assumptions in quantum mechanics - a very general one. We shall derive the lagrangian path integral in the “product form” definition and shall also prove that the Schro¨dinger equation can be derived from the corresponding short-time kernel. We shall discuss briefly an application of this prescription to the problem of free quantum motion on the Poincare´upper half-plane.

  10. What is the definition of sports-related concussion: a systematic review.

    Science.gov (United States)

    McCrory, Paul; Feddermann-Demont, Nina; Dvořák, Jiří; Cassidy, J David; McIntosh, Andrew; Vos, Pieter E; Echemendia, Ruben J; Meeuwisse, Willem; Tarnutzer, Alexander A

    2017-06-01

    Various definitions for concussion have been proposed, each having its strengths and weaknesses. We reviewed and compared current definitions and identified criteria necessary for an operational definition of sports-related concussion (SRC) in preparation of the 5th Concussion Consensus Conference (Berlin, Germany). We also assessed the role of biomechanical studies in informing an operational definition of SRC. This is a systematic literature review. Data sources include MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Clinical Trials and SPORT Discus (accessed 14 September 2016). Eligibility criteria were studies reporting (clinical) criteria for diagnosing SRC and studies containing SRC impact data. Out of 1601 articles screened, 36 studies were included (2.2%), 14 reported on criteria for SRC definitions and 22 on biomechanical aspects of concussions. Six different operational definitions focusing on clinical findings and their dynamics were identified. Biomechanical studies were obtained almost exclusively on American football players. Angular and linear head accelerations linked to clinically confirmed concussions demonstrated considerable individual variation. SRC is a traumatic brain injury that is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces with several common features that help define its nature. Limitations identified include that the current criteria for diagnosing SRC are clinically oriented and that there is no gold/standard to assess their diagnostic properties. A future, more valid definition of SRC would better identify concussed players by demonstrating high predictive positive/negative values. Currently, the use of helmet-based systems to study the biomechanics of SRC is limited to few collision sports. New approaches need to be developed to provide objective markers for SRC. © Article author(s) (or their employer(s) unless otherwise

  11. Exploring Mathematical Definition Construction Processes

    Science.gov (United States)

    Ouvrier-Buffet, Cecile

    2006-01-01

    The definition of "definition" cannot be taken for granted. The problem has been treated from various angles in different journals. Among other questions raised on the subject we find: the notions of "concept definition" and "concept image", conceptions of mathematical definitions, redefinitions, and from a more axiomatic point of view, how to…

  12. 15 CFR 922.81 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Definitions. 922.81 Section 922.81... Definitions. In addition to those definitions found at § 922.3, the following definitions apply to this... or otherwise manifesting intention not to undertake or to cease salvage efforts, or when the owner...

  13. The quantum hydrodynamics of the Sutherland model

    International Nuclear Information System (INIS)

    Stone, Michael; Gutman, Dmitry

    2008-01-01

    We show that the form of the chiral condition found by Abanov et al in the quantum hydrodynamics of the Sutherland model arises because there are two distinct inner products with respect to which the chiral Hamiltonian is Hermitian, but only one with respect to which the full, non-chiral, Hamiltonian is Hermitian

  14. Bullying by Definition: An Examination of Definitional Components of Bullying

    Science.gov (United States)

    Goldsmid, Susan; Howie, Pauline

    2014-01-01

    Lack of definitional consensus remains an important unresolved issue within bullying research. This study examined the ability of definitional variables to predict overall level of victimisation (distress, power inequity, and provocation as predictors) and bullying (intention to harm, power inequity, and provocation as predictors) in 246…

  15. Determination of neuronal antibodies in suspected and definite Creutzfeldt-Jakob disease.

    Science.gov (United States)

    Grau-Rivera, Oriol; Sánchez-Valle, Raquel; Saiz, Albert; Molinuevo, José Luis; Bernabé, Reyes; Munteis, Elvira; Pujadas, Francesc; Salvador, Antoni; Saura, Júlia; Ugarte, Antonio; Titulaer, Maarten; Dalmau, Josep; Graus, Francesc

    2014-01-01

    Creutzfeldt-Jakob disease (CJD) and autoimmune encephalitis with antibodies against neuronal surface antigens (NSA-abs) may present with similar clinical features. Establishing the correct diagnosis has practical implications in the management of care for these patients. To determine the frequency of NSA-abs in the cerebrospinal fluid of patients with suspected CJD and in patients with pathologically confirmed (ie, definite) CJD. A mixed prospective (suspected) and retrospective (definite) CJD cohort study was conducted in a reference center for detection of NSA-abs. The population included 346 patients with suspected CJD and 49 patients with definite CJD. Analysis of NSA-abs in cerebrospinal fluid with brain immunohistochemistry optimized for cell-surface antigens was performed. Positive cases in the suspected CJD group were further studied for antigen specificity using cell-based assays. All definite CJD cases were comprehensively tested for NSA-abs, with cell-based assays used for leucine-rich glioma-inactivated 1 (LGI1), contactin-associated protein-like 2 (CASPR2), N-methyl-d-aspartate (NMDA), and glycine (GlY) receptors. Neuronal surface antigens were detected in 6 of 346 patients (1.7%) with rapid neurologic deterioration suggestive of CJD. None of these 6 patients fulfilled the diagnostic criteria for probable or possible CJD. The target antigens included CASPR2, LGI1, NMDAR, aquaporin 4, Tr (DNER [δ/notch-like epidermal growth factor-related receptor]), and an unknown protein. Four of the patients developed rapidly progressive dementia, and the other 2 patients had cerebellar ataxia or seizures that were initially considered to be myoclonus without cognitive decline. The patient with Tr-abs had a positive 14-3-3 test result. Small cell lung carcinoma was diagnosed in the patient with antibodies against an unknown antigen. All patients improved or stabilized after appropriate treatment. None of the 49 patients with definite CJD had NSA-abs. A low, but

  16. Digital impressions for fabrication of definitive "all-on-four" restorations.

    Science.gov (United States)

    Gherlone, Enrico Felice; Ferrini, Francesco; Crespi, Roberto; Gastaldi, Giorgio; Capparé, Paolo

    2015-02-01

    The aim of this study was to assess the accuracy of digital impressions for "all-on-four" implant rehabilitation. Patients edentulous in one or both jaws were randomly selected for this study. Complete arch immediately loaded prostheses supported by 4 implants (2 axial and 2 tilted) were placed. Five hours after implant placement, screw-retained full-arch temporary prostheses were positioned. After 4 months, a digital scan body was used to finalize definitive prosthesis. Radiographic assessments were obtained immediately after surgery and at each follow-up visit. Bone level measurements were reported at 6 and 12 months, and bone loss between upright and tilted implants was compared. Fourteen definitive cast metal frameworks prosthesis were delivered to the patients. No implant dropout occurred. All prosthesis were screwed onto the dental implants, and x-ray examinations revealed a bar-implant connection accuracy. The implant survival rate was 100% for all positioned implants. No statistically significant differences (P > 0.05) in crestal bone loss between tilted and upright implants were detected. Digital impression creates an accurate physical model significantly improving efficiencies for the dental team and streamlining the workflow.

  17. INCORPORATING ROUTINE ACTIVITIES, ACTIVITY SPACES, AND SITUATIONAL DEFINITIONS INTO THE SOCIAL SCHEMATIC THEORY OF CRIME*

    Science.gov (United States)

    BARR, ASHLEY B.; LEI, MAN-KIT; STEWART, ERIC

    2014-01-01

    Simons and Burt’s (2011) social schematic theory (SST) of crime posits that adverse social factors are associated with offending because they promote a set of social schemas (i.e., a criminogenic knowledge structure) that elevates the probability of situational definitions favorable to crime. This study extends the SST model by incorporating the role of contexts for action. Furthermore, the study advances tests of the SST by incorporating a measure of criminogenic situational definitions to assess whether such definitions mediate the effects of schemas and contexts on crime. Structural equation models using 10 years of panel data from 582 African American youth provided strong support for the expanded theory. The results suggest that childhood and adolescent social adversity fosters a criminogenic knowledge structure as well as selection into criminogenic activity spaces and risky activities, all of which increase the likelihood of offending largely through situational definitions. Additionally, evidence shows that the criminogenic knowledge structure interacts with settings to amplify the likelihood of situational definitions favorable to crime. PMID:26392633

  18. The Berlin definition of ARDS: an expanded rationale, justification, and supplementary material.

    Science.gov (United States)

    Ferguson, Niall D; Fan, Eddy; Camporota, Luigi; Antonelli, Massimo; Anzueto, Antonio; Beale, Richard; Brochard, Laurent; Brower, Roy; Esteban, Andrés; Gattinoni, Luciano; Rhodes, Andrew; Slutsky, Arthur S; Vincent, Jean-Louis; Rubenfeld, Gordon D; Thompson, B Taylor; Ranieri, V Marco

    2012-10-01

    Our objective was to revise the definition of acute respiratory distress syndrome (ARDS) using a conceptual model incorporating reliability and validity, and a novel iterative approach with formal evaluation of the definition. The European Society of Intensive Care Medicine identified three chairs with broad expertise in ARDS who selected the participants and created the agenda. After 2 days of consensus discussions a draft definition was developed, which then underwent empiric evaluation followed by consensus revision. The Berlin Definition of ARDS maintains a link to prior definitions with diagnostic criteria of timing, chest imaging, origin of edema, and hypoxemia. Patients may have ARDS if the onset is within 1 week of a known clinical insult or new/worsening respiratory symptoms. For the bilateral opacities on chest radiograph criterion, a reference set of chest radiographs has been developed to enhance inter-observer reliability. The pulmonary artery wedge pressure criterion for hydrostatic edema was removed, and illustrative vignettes were created to guide judgments about the primary cause of respiratory failure. If no risk factor for ARDS is apparent, however, objective evaluation (e.g., echocardiography) is required to help rule out hydrostatic edema. A minimum level of positive end-expiratory pressure and mutually exclusive PaO(2)/FiO(2) thresholds were chosen for the different levels of ARDS severity (mild, moderate, severe) to better categorize patients with different outcomes and potential responses to therapy. This panel addressed some of the limitations of the prior ARDS definition by incorporating current data, physiologic concepts, and clinical trials results to develop the Berlin definition, which should facilitate case recognition and better match treatment options to severity in both research trials and clinical practice.

  19. Influence of Peer Social Experiences on Positive and Negative Indicators of Mental Health among High School Students

    Science.gov (United States)

    Suldo, Shannon M.; Gelley, Cheryl D.; Roth, Rachel A.; Bateman, Lisa P.

    2015-01-01

    Modern definitions of complete mental health include both positive and negative indicators of psychological functioning. We examined the associations between peer relationships (victimization and receipt of prosocial acts) and multiple indicators of mental health that represent subjective well-being (i.e., life satisfaction, positive and negative…

  20. Positive emotions, spirituality and the practice of psychiatry.

    Science.gov (United States)

    Vaillant, George E

    2008-01-01

    THIS PAPER PROPOSES THAT EIGHT POSITIVE EMOTIONS: awe, love (attachment), trust (faith), compassion, gratitude, forgiveness, joy and hope constitute what we mean by spirituality. These emotions have been grossly ignored by psychiatry. The two sciences that I shall employ to demonstrate this definition of spirituality will be ethology and neuroscience. They are both very new. I will argue that spirituality is not about ideas, sacred texts and theology; rather, spirituality is all about emotion and social connection.Specific religions, for all their limitations, are often the portal through which positive emotions are brought into conscious attention. Neither Freud nor psychiatric textbooks ever mention emotions like joy and gratitude. Hymns and psalms give these emotions pride of place. Our whole concept of psychotherapy might change if clinicians set about enhancing positive emotions rather than focusing only on negative emotions.

  1. Developing a comprehensive definition of sustainability.

    Science.gov (United States)

    Moore, Julia E; Mascarenhas, Alekhya; Bain, Julie; Straus, Sharon E

    2017-09-02

    Understanding sustainability is one of the significant implementation science challenges. One of the big challenges in researching sustainability is the lack of consistent definitions in the literature. Most implementation studies do not present a definition of sustainability, even when assessing sustainability. The aim of the current study was to systematically develop a comprehensive definition of sustainability based on definitions already used in the literature. We searched for knowledge syntheses of sustainability and abstracted sustainability definitions from the articles identified through any relevant systematic and scoping reviews. The constructs in the abstracted sustainability definitions were mapped to an existing definition. The comprehensive definition of sustainability was revised to include emerging constructs. We identified four knowledge syntheses of sustainability, which identified 209 original articles. Of the 209 articles, 24 (11.5%) included a definition of sustainability. These definitions were mapped to three constructs from an existing definition, and nine new constructs emerged. We reviewed all constructs and created a revised definition: (1) after a defined period of time, (2) a program, clinical intervention, and/or implementation strategies continue to be delivered and/or (3) individual behavior change (i.e., clinician, patient) is maintained; (4) the program and individual behavior change may evolve or adapt while (5) continuing to produce benefits for individuals/systems. All 24 definitions were remapped to the comprehensive definition (percent agreement among three coders was 94%). Of the 24 definitions, 17 described the continued delivery of a program (70.8%), 17 mentioned continued outcomes (70.8%), 13 mentioned time (54.2%), 8 addressed the individual maintenance of a behavior change (33.3%), and 6 described the evolution or adaptation (25.0%). We drew from over 200 studies to identify 24 existing definitions of sustainability

  2. SOME IMPORTANTS DEFINITIONS AND MESUREMENT METHODS OF CORPORATE REPUTATION

    Directory of Open Access Journals (Sweden)

    MIHAELA SANDU

    2012-12-01

    Full Text Available Reputation is one of the most important intangible corporate active. In the literature we can find different definitions and methods of measurement for reputation. In this paper we will emphasize some of them. We will see how increased the importance of reputation in the last years. We will see how important this asset is for the company and how a positive reputation determines the competitive advantage for the company.

  3. Validation of an algorithm-based definition of treatment resistance in patients with schizophrenia.

    Science.gov (United States)

    Ajnakina, Olesya; Horsdal, Henriette Thisted; Lally, John; MacCabe, James H; Murray, Robin M; Gasse, Christiane; Wimberley, Theresa

    2018-02-19

    Large-scale pharmacoepidemiological research on treatment resistance relies on accurate identification of people with treatment-resistant schizophrenia (TRS) based on data that are retrievable from administrative registers. This is usually approached by operationalising clinical treatment guidelines by using prescription and hospital admission information. We examined the accuracy of an algorithm-based definition of TRS based on clozapine prescription and/or meeting algorithm-based eligibility criteria for clozapine against a gold standard definition using case notes. We additionally validated a definition entirely based on clozapine prescription. 139 schizophrenia patients aged 18-65years were followed for a mean of 5years after first presentation to psychiatric services in South-London, UK. The diagnostic accuracy of the algorithm-based measure against the gold standard was measured with sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). A total of 45 (32.4%) schizophrenia patients met the criteria for the gold standard definition of TRS; applying the algorithm-based definition to the same cohort led to 44 (31.7%) patients fulfilling criteria for TRS with sensitivity, specificity, PPV and NPV of 62.2%, 83.0%, 63.6% and 82.1%, respectively. The definition based on lifetime clozapine prescription had sensitivity, specificity, PPV and NPV of 40.0%, 94.7%, 78.3% and 76.7%, respectively. Although a perfect definition of TRS cannot be derived from available prescription and hospital registers, these results indicate that researchers can confidently use registries to identify individuals with TRS for research and clinical practices. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. EXISTENCE OF POSITIVE PERIODIC SOLUTION TO A CLASS OF NONAUTONOMOUS DIFFERENTIAL EQUATION WITH IMPULSES AND DELAY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, by fixed point theorem of Krasnoselskii, we study the positive pe- riodic solution to a class of nonautonomous differential equation with impulses and delay. Firstly, definition of periodic solution and some lemmas are stated. Then some results on the existence of positive periodic solution to the equation are obtained.

  5. Analysis of positioning errors in radiotherapy; Analyse des erreurs de positionnement en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Josset-Gaudaire, S.; Lisbona, A.; Llagostera, C.; Delpon, G.; Chiavassa, S.; Brunet, G. [Service de physique medicale, ICO Rene-Gauducheau, Saint Herblain (France); Rousset, S.; Nerriere, E.; Leblanc, M. [Service de radiotherapie, ICO Rene-Gauducheau, Saint Herblain (France)

    2011-10-15

    Within the frame of a study of control imagery management in radiotherapy, the authors report the study of positioning errors associated with control imagery in order to give an overview of practice and to help the adjustment or definition of action levels for clinical practice. Twenty groups of patients have been defined by considering tumour locations (head, ENT, thorax, breast, abdomen, and pelvis), treatment positions, immobilization systems and imagery systems. Positioning errors have thus been analyzed for 340 patients. Aspects and practice to be improved are identified. Short communication

  6. Defending definitions of life.

    Science.gov (United States)

    Mix, Lucas John

    2015-01-01

    Over the past 10 years, it has become unpopular to talk about definitions of life, under the assumption that attempts at a precise definition are counterproductive. Recent attempts have failed to meet strict philosophical criteria for definitions and have failed to reach consensus. I argue that provisional definitions are necessary for clear communications. Our current knowledge of biology justifies a number of universal claims about the category of life. Whether or not "life" represents a natural category, it maps to a number of important, observable processes. Given the importance of those processes and the extent of our knowledge, plural explicit definitions of life (and related categories) will be necessary for progress in astrobiology and origin-of-life studies as well as biology in general. I propose concrete categories related to, but not necessarily coextensive with, life for clear communication and hypothesis formation: Woese life, Darwin life, Haldane life.

  7. Autobiographical memories for negative and positive events in war contexts

    Directory of Open Access Journals (Sweden)

    Antonio L. Manzanero

    2015-01-01

    Full Text Available The aim of the present study was to examine the phenomenological qualities of self-reported negative and positive memories. The study was conducted in the Gaza Strip, Palestine, and a total of 134 autobiographical memories about negative and positive events were analyzed using a version of the Phenomenological Questionnaire for Autobiographical Memory (Manzanero & López, 2007. Participants were university students, 80 percent were women and 20 percent were men. Results showed that negative memories are more confused, more complex, and decay more over time than positive ones. In contrast, no differences were found between positive and negative memories on sensory information, spatial location, vividness, definition, accessibility, fragmentation, recall perspective, doubts about the accuracy of the memory, and how much participants recovered and talked about the event. High Dimensional Visualization (HDV graph revealed that there were individual differences between negative and positive memories but no consistent differences across participants.

  8. Controversy around the definition of waste

    CSIR Research Space (South Africa)

    Oelofse, Suzanna HH

    2009-11-20

    Full Text Available This paper presents the information concerning the definition of waste. Discussing the importance of the clear definition, ongoing debates, broad definition of waste, problems with the broad definition, interpretation, current waste management model...

  9. Some spectral equivalences between Schroedinger operators

    International Nuclear Information System (INIS)

    Dunning, C; Hibberd, K E; Links, J

    2008-01-01

    Spectral equivalences of the quasi-exactly solvable sectors of two classes of Schroedinger operators are established, using Gaudin-type Bethe ansatz equations. In some instances the results can be extended leading to full isospectrality. In this manner we obtain equivalences between PT-symmetric problems and Hermitian problems. We also find equivalences between some classes of Hermitian operators

  10. Engineering Definitional Interpreters

    DEFF Research Database (Denmark)

    Midtgaard, Jan; Ramsay, Norman; Larsen, Bradford

    2013-01-01

    A definitional interpreter should be clear and easy to write, but it may run 4--10 times slower than a well-crafted bytecode interpreter. In a case study focused on implementation choices, we explore ways of making definitional interpreters faster without expending much programming effort. We imp...

  11. An integrative discourse perspective on positive leadership in public health care.

    Science.gov (United States)

    Pietiläinen, Ville; Salmi, Ilkka

    2017-02-06

    Purpose This study aims to take a discursive view on positive leadership (PL). A positive approach has gained momentum in recent years as appropriate leadership practices are implemented in organizations. Despite the turn toward discursive approaches in organization studies, there is insufficient evidence supporting PL as a socially constructed experience. Design/methodology/approach The present study addresses an integrative discourse perspective for capturing the PL concept as a social process within the public health-care context. Findings Four meanings of PL are highlighted: role-taking, servicing, balancing and deciphering. Research limitations/implications The meanings shift the emphasis of certain PL definitions to a contextual interpretation. For scholars, the perspective demonstrates a multidimensional process approach in the desired organizational context as a counterbalance to one unanimously agreed-upon PL definition. Practical implications For leaders, an integrative discourse perspective offers tools for comprehending PL as a process: how to identify, negotiate and reconcile various PL meanings. Originality/value An integrative discourse perspective provides a novel perspective capturing the PL concept within the public health-care field.

  12. The definition of biochemical failure in patients treated with definitive radiotherapy

    International Nuclear Information System (INIS)

    Kattan, Michael W.; Fearn, Paul A.; Leibel, Steven; Potters, Louis

    2000-01-01

    Purpose: The American Society for Therapeutic Radiology and Oncology (ASTRO) published a definition for biochemical failure following treatment of prostate cancer. Others have noted difficulties with interpreting this definition and recommended modifications to accommodate special recurrence patterns. We have compared various modifications to the original ASTRO definition on our series of 1213 patients treated with transperineal permanent prostate brachytherapy. Methods and Materials: The ASTRO modifications we considered adjusted for (1) early censoring of nonrecurrent patients with rising prostate-specific antigen levels (PSA), (2) cumulative rather than consecutive rises (without a decrease) as evidence of recurrence, (3) both of the above, and (4) waiting 2 years before data analysis. The Kaplan-Meier method was used to compute the effects on recurrence rate for patients treated with and without neoadjuvant hormones. Results: With the original ASTRO definition, freedom from recurrence in our series of men who did not receive neoadjuvant hormones was 83% at 4 years. All of the modifications considered had statistically insignificant effects on freedom from recurrence rates, varying from 80% to 83% at 4 years. Patients treated with neoadjuvant hormones also showed very little sensitivity to the recurrence definition employed. Conclusion: Early censoring of equivocal patients and counting cumulative rather than consecutive rises in PSA (without a decrease) had little empiric effect on the ASTRO recurrence rates. However, we favor the addition of both these modifications to the ASTRO definition on conceptual grounds for evaluating patients following any modality (radiation or surgery), whereby a trend over multiple PSA values is used to judge failure.

  13. The definition of cross polarization

    DEFF Research Database (Denmark)

    Ludwig, Arthur

    1973-01-01

    There are at least three different definitions of cross polarization used in the literature. The alternative definitions are discussed with respect to several applications, and the definition which corresponds to one standard measurement practice is proposed as the best choice....

  14. WHO Severe Acute Respiratory Infections (SARI) Definition often Underdiagnoses Serious Respiratory Viral Infections in Hospitalized Jordanian Children

    Science.gov (United States)

    Khuri-Bulos, Najwa; Piya, Bhinnata; Shehabi, Asem; Faouri, Samir; Williams, John V; Vermund, Sten; Halasa, Natasha B

    2017-01-01

    Abstract Background The World Health Organization (WHO) case definition of severe acute respiratory infections (SARI) is anyone with an acute respiratory infection with symptoms within 10 days of presentation, cough, fever, and hospitalization. This is used to standardize global influenza surveillance with the caveat not all cases will be captured. We sought to determine the proportion of hospitalized Jordanian children admitted with acute respiratory illnesses meeting the SARI definition. Methods We conducted 3-year viral surveillance study in children <2 years admitted with acute respiratory symptoms and/or fever into a large government hospital in Amman. Demographic and clinical data were collected. We tested nasal/throat swabs for 11 viruses using q-RT-PCR. We compared children who met SARI definition to non-SARI. Results We enrolled 3168 children. Table 1 compares those children who met SARI definition vs. those who did not. Figure 1 compares % of children who were virus-positive and met SARI definition. Table 1. N (%) SARI (n = 1198) Non-SARI (n = 1970) p-values Male 729 (60.9) 1183 (60.1) 0.655 Median Age 6.7 months 2.3 months 0.000 Underlying medical condition 160 (13.4) 215 (10.9) 0.039 Pneumonia 192 (16.0) 202 (10.3) 0.000 Sepsis 150 (12.5) 750 (38.1) 0.000 Bronchiolitis 169 (14.1) 378 (19.2) 0.000 Bronchopneumonia 656 (54.8) 364 (18.5) 0.000 ≤10-day duration 1198 (100) 1848 (93.8) 0.000 Cough 1198 (100) 1172 (59.5) 0.000 Fever 1198 (100) 649 (32.9) 0.000 Fever and Cough 1198 (100) 48 (2.4) 0.000 Virus positive 1076 (89.8) 1505 (76.4) 0.000 Rhinovirus 438 (36.6) 800 (40.6) 0.024 Adenovirus 201 (16.8) 274 (13.9) 0.028 Parainfluenza 1–3 75 (6.3) 100 (5.1) 0.157 Respiratory Syncytial Virus 635 (53.0) 762 (38.7) 0.000 Influenza A-C 61 (5.1) 58 (2.9) 0.002 Human Metapneumovirus 153 (12.8) 120 (6.1) 0.000 Conclusion Children who met the definition of SARI were more likely to be older, have an underlying medical condition, have the diagnoses of pneumonia and

  15. High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus.

    Science.gov (United States)

    Sami, S S; Subramanian, V; Butt, W M; Bejkar, G; Coleman, J; Mannath, J; Ragunath, K

    2015-01-01

    High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time. © 2014 International Society for Diseases of the Esophagus.

  16. Positional therapy in sleep apnoea - one fits all? What determines success in positional therapy in sleep apnoea syndrome.

    Directory of Open Access Journals (Sweden)

    Natascha Troester

    Full Text Available Positional therapy is a simple means of therapy in sleep apnoea syndrome, but due to controversial or lacking evidence, it is not widely accepted as appropriate treatment. In this study, we analysed data to positional therapy with regard to successful reduction of AHI and predictors of success.All consecutive patients undergoing polysomnography between 2007 and 2011 were analysed. We used a strict definition of positional sleep apnoea syndrome (supine-exclusive sleep apnoea syndrome and of therapy used. Patients underwent polysomnography initially and during follow-up.1275 patients were evaluated, 112 of which had supine-exclusive sleep apnoea syndrome (AHI 5-66/h, median 13/h, 105 received positional therapy. With this treatment alone 75% (70/105 reached an AHI <5/h, in the follow-up 1 year later 37% (37/105 of these still had AHI<5/h, 46% (43/105 yielded an AHI between 5 and 10/h. Nine patient switched to APAP due to deterioration, 3 wanted to try APAP due to comfort reasons. At the last follow-up, 32% patients (34/105 were still on positional therapy with AHI <5/h. BMI was a predictor for successful reduction of AHI, but success was independent of sex, the presence of obstructive versus central sleep apnoea, severity of sleep apnoea syndrome or co-morbidities.Positional therapy may be a promising therapy option for patients with positional sleep apnoea. With appropriate adherence it yields a reasonable success rate in the clinical routine.

  17. 16 CFR 1404.3 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Definitions. 1404.3 Section 1404.3... INSULATION § 1404.3 Definitions. The definitions in section 3 of the Consumer Product Safety Act (15 U.S.C... as the marketer of the brand). ...

  18. Dual, use-based definition of "system"

    CSIR Research Space (South Africa)

    Gonçalves, DP

    2015-09-01

    Full Text Available The standard definition (ISO 15288, 2008) of the concept of a system is not complete and is the definition of a closed system. Such a definition is inadequate for systems engineering. A use-based definition is proposed which spans the open...

  19. On the definition of absorbed dose

    International Nuclear Information System (INIS)

    Grusell, Erik

    2015-01-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before. - Highlights: • A stringent definition of absorbed dose is given. • This requires the definition of an irradiation and a suitable probability space. • A stringent definition is important for an understanding of the concept absorbed dose

  20. 7 CFR 1775.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... Utilities Service, an Agency of the United States Department of Agriculture. Solid Waste Management. Refers... 7 Agriculture 12 2010-01-01 2010-01-01 false Definitions. 1775.2 Section 1775.2 Agriculture... (CONTINUED) TECHNICAL ASSISTANCE GRANTS General Provisions § 1775.2 Definitions. The following definitions...

  1. 40 CFR 51.1000 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Definitions. 51.1000 Section 51.1000 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR... Ambient Air Quality Standards § 51.1000 Definitions. The following definitions apply for purposes of this...

  2. 42 CFR 1000.10 - General definitions.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false General definitions. 1000.10 Section 1000.10 Public Health OFFICE OF INSPECTOR GENERAL-HEALTH CARE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS INTRODUCTION; GENERAL DEFINITIONS Definitions § 1000.10 General definitions. In this chapter...

  3. 47 CFR 101.1112 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Definitions. 101.1112 Section 101.1112... SERVICES Competitive Bidding Procedures for LMDS § 101.1112 Definitions. (a) Scope. The definitions in this... million. (d) Entrepreneur. An entrepreneur is an entity that, together with its affiliates and controlling...

  4. 5 CFR 362.101 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Definitions. 362.101 Section 362.101... PROGRAM Definitions § 362.101 Definitions. For purposes of this part, An agency means a component within... outstanding record of achievement in an applicable leadership, policy, managerial, professional, or technical...

  5. Nuclear technology terms and definitions

    International Nuclear Information System (INIS)

    1979-02-01

    The terms and definitions in this standard are part of the catalogue of definitions 'Nuclear technology, terms and definitions', in eight parts; they are the latest version of the standards and draft standards of DIN 25 401, part 10 to 19, published at irregular intervals until now. (orig.) [de

  6. 40 CFR 61.101 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... definition of reference man are outlined in the International Commission on Radiological Protection's... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Definitions. 61.101 Section 61.101....101 Definitions. As used in this subpart, all terms not defined here have the meaning given them in...

  7. 10 CFR 1800.11 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Definitions. 1800.11 Section 1800.11 Energy NORTHEAST... INTERSTATE LOW-LEVEL RADIOACTIVE WASTE COMPACT § 1800.11 Definitions. The definitions contained in Article II..., corporation, business enterprise or other legal entity, either public or private, and expressly includes...

  8. 24 CFR 241.800 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... SUPPLEMENTARY FINANCING FOR INSURED PROJECT MORTGAGES Contract Rights and Obligations-Multifamily Projects Without a HUD-Insured or HUD-Held Mortgage § 241.800 Definitions. All of the definitions contained in... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Definitions. 241.800 Section 241...

  9. 13 CFR 120.351 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Definitions. 120.351 Section 120.351 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Special Purpose Loans Qualified Employee Trusts (esop) § 120.351 Definitions. All terms specific to ESOPs have the same definition...

  10. 23 CFR 230.202 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... for Minority, Disadvantaged, and Women Business Enterprises § 230.202 Definitions. (a) Minority... disadvantaged business enterprise (DBE), all defined under 49 CFR part 23. This expanded definition is used only... 23 Highways 1 2010-04-01 2010-04-01 false Definitions. 230.202 Section 230.202 Highways FEDERAL...

  11. 23 CFR 635.102 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... MAINTENANCE Contract Procedures § 635.102 Definitions. As used in this subpart: Administrator means the... definition is set forth in the State contract specifications, that definition will apply. Contract time means the number of workdays or calendar days specified in a contract for completion of the contract work...

  12. On the definition of 'chaos'

    International Nuclear Information System (INIS)

    Kolesov, Andrei Yu; Rozov, Nikolai Kh

    2009-01-01

    A new definition of a chaotic invariant set is given for a continuous semiflow in a metric space. It generalizes the well-known definition due to Devaney and allows one to take into account a special feature occurring in the non-compact infinite-dimensional case: so-called turbulent chaos. The paper consists of two sections. The first contains several well-known facts from chaotic dynamics, together with new definitions and results. The second presents a concrete example demonstrating that our definition of chaos is meaningful. Namely, an infinite-dimensional system of ordinary differential equations is investigated having an attractor that is chaotic in the sense of the new definition but not in the sense of Devaney or Knudsen. Bibliography: 65 titles.

  13. Prognostic Significance of Progesterone Receptor–Positive Tumor Cells Within Immunohistochemically Defined Luminal A Breast Cancer

    Science.gov (United States)

    Prat, Aleix; Cheang, Maggie Chon U.; Martín, Miguel; Parker, Joel S.; Carrasco, Eva; Caballero, Rosalía; Tyldesley, Scott; Gelmon, Karen; Bernard, Philip S.; Nielsen, Torsten O.; Perou, Charles M.

    2013-01-01

    Purpose Current immunohistochemical (IHC)-based definitions of luminal A and B breast cancers are imperfect when compared with multigene expression-based assays. In this study, we sought to improve the IHC subtyping by examining the pathologic and gene expression characteristics of genomically defined luminal A and B subtypes. Patients and Methods Gene expression and pathologic features were collected from primary tumors across five independent cohorts: British Columbia Cancer Agency (BCCA) tamoxifen-treated only, Grupo Español de Investigación en Cáncer de Mama 9906 trial, BCCA no systemic treatment cohort, PAM50 microarray training data set, and a combined publicly available microarray data set. Optimal cutoffs of percentage of progesterone receptor (PR) –positive tumor cells to predict survival were derived and independently tested. Multivariable Cox models were used to test the prognostic significance. Results Clinicopathologic comparisons among luminal A and B subtypes consistently identified higher rates of PR positivity, human epidermal growth factor receptor 2 (HER2) negativity, and histologic grade 1 in luminal A tumors. Quantitative PR gene and protein expression were also found to be significantly higher in luminal A tumors. An empiric cutoff of more than 20% of PR-positive tumor cells was statistically chosen and proved significant for predicting survival differences within IHC-defined luminal A tumors independently of endocrine therapy administration. Finally, no additional prognostic value within hormonal receptor (HR) –positive/HER2-negative disease was observed with the use of the IHC4 score when intrinsic IHC-based subtypes were used that included the more than 20% PR-positive tumor cells and vice versa. Conclusion Semiquantitative IHC expression of PR adds prognostic value within the current IHC-based luminal A definition by improving the identification of good outcome breast cancers. The new proposed IHC-based definition of luminal A

  14. The Need for Consensus and Transparency in Assessing Population-Based Rates of Positive Circumferential Radial Margins in Rectal Cancer: Data from Consecutive Cases in a Large Region of Ontario, Canada.

    Science.gov (United States)

    Keng, Christine; Coates, Angela; Grubac, Vanja; Lovrics, Peter; DeNardi, Franco; Thabane, Lehana; Simunovic, Marko

    2016-02-01

    A positive circumferential radial margin (CRM) after rectal cancer surgery is an important predictor of local recurrence. The definition of a positive CRM differs internationally, and reported rates vary greatly in the literature. This study used time-series population-based data to assess positive CRM rates in a region over time and to inform future methods of CRM analysis in a defined geographic area. Chart reviews provided relevant data from consecutive patients undergoing rectal cancer surgery between 2006 and 2012 in all hospitals of the authors' region. Outcomes included rates for pathologic examination of CRM, CRM distance reporting, and positive CRM. The rate of positive CRM was calculated using various definitions. The variations included positive margin cutoffs of CRM at 1 mm or less versus 2 mm or less and inclusion or exclusion of cases without CRM assessment. In this study, 1222 consecutive rectal cancer cases were analyzed. The rate for pathology reporting of CRM distance increased from 54.7 to 93.2 % during the study. Depending on how the rate of positive CRM was defined, its value varied 8.5 to 19.4 % in 2006 and 6.0 to 12.5 % in 2012. Using a pre-specified definition, the rate of positive CRM decreased over time from 14.0 to 6.3 %. A marked increase in CRM distance reporting was observed, whereas the rates of positive CRM dropped, suggesting improved pathologist and surgeon performance over time. Changing definitions greatly influenced the rates of positive CRM, indicating the need for more transparency when such population-based rates are reported in the literature.

  15. 40 CFR 61.91 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... included. The method for calculating effective dose equivalent and the definition of reference man are... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Definitions. 61.91 Section 61.91... Other Than Radon From Department of Energy Facilities § 61.91 Definitions. As used in this subpart, all...

  16. 50 CFR 21.3 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Definitions. 21.3 Section 21.3 Wildlife... (CONTINUED) MIGRATORY BIRD PERMITS Introduction § 21.3 Definitions. In addition to definitions contained in... environment that is intensively manipulated by man for the purpose of producing raptors of selected species...

  17. 24 CFR 241.1005 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... SUPPLEMENTARY FINANCING FOR INSURED PROJECT MORTGAGES Insurance for Equity Loans and Acquisition Loans-Eligibility Requirements § 241.1005 Definitions. (a) All of the definitions of § 241.1 apply to equity and... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Definitions. 241.1005 Section 241...

  18. 24 CFR 241.260 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... SUPPLEMENTARY FINANCING FOR INSURED PROJECT MORTGAGES Contract Rights and Obligations § 241.260 Definitions. All of the definitions contained in § 241.1 shall apply to this subpart. In addition, the term contract... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Definitions. 241.260 Section 241...

  19. 40 CFR 26.202 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Definitions. 26.202 Section 26.202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Prohibition of... Pregnant or Nursing Women § 26.202 Definitions. The definitions in § 26.102 shall be applicable to this...

  20. 40 CFR 26.1202 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Definitions. 26.1202 Section 26.1202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Prohibition of... Pregnant or Nursing Women § 26.1202 Definitions. The definitions in § 26.1102 shall be applicable to this...

  1. Extended space expectation values of position related operators for hydrogen-like quantum system evolutions

    International Nuclear Information System (INIS)

    Kalay, Berfin; Demiralp, Metin

    2014-01-01

    The expectation value definitions over an extended space from the considered Hilbert space of the system under consideration is given in another paper of the second author in this symposium. There, in that paper, the conceptuality rather than specification is emphasized on. This work uses that conceptuality to investigate the time evolutions of the position related operators' expectation values not in its standard meaning but rather in a new version of the definition over not the original Hilbert space but in the space obtained by extensions via introducing the images of the given initial wave packet under the positive integer powers of the system Hamiltonian. These images may not be residing in the same space of the initial wave packet when certain singularities appear in the structure of the system Hamiltonian. This may break down the existence of the integrals in the definitions of the expectation values. The cure is the use of basis functions in the abovementioned extended space and the sandwiching of the target operator whose expectation value is under questioning by an appropriately chosen operator guaranteeing the existence of the relevant integrals. Work specifically focuses on the hydrogen-like quantum systems whose Hamiltonians contain a polar singularity at the origin

  2. Pharmaceutical care: the PCNE definition 2013.

    Science.gov (United States)

    Allemann, Samuel S; van Mil, J W Foppe; Botermann, Lea; Berger, Karin; Griese, Nina; Hersberger, Kurt E

    2014-06-01

    Twenty-three years after Hepler and Strand published their well-known definition of Pharmaceutical Care (PhC), confusion remains about what the term includes and how to differentiate it from other terms. The board of the Pharmaceutical Care Network Europe (PCNE) felt the need to redefine PhC and to answer the question: "What is Pharmaceutical Care in 2013". The aims of this paper were to review existing definitions of PhC and to describe the process of developing a redefined definition. A literature search was conducted in the MEDLINE database (1964-January 2013). Keywords included "Pharmaceutical Care", "Medication (Therapy) Management", "Medicine Management", and "Pharmacist Care" in the title or abstract together with the term "defin*". To ease comparison between definitions, we developed a standardised syntax to paraphrase the definitions. During a dedicated meeting, a moderated discussion about the definition of PhC was organised. The initial literature search produced 186 hits, with eight unique PhC definitions. Hand searching identified a further 11 unique definitions. These 19 definitions were paraphrased using the standardised syntax (provider, recipient, subject, outcome, activities). Fourteen members of PCNE and 10 additional experts attended the moderated discussion. Working groups of increasing size developed intermediate definitions, which had similarities and differences to those retrieved in the literature search. At the end of the session, participants reached a consensus on a "PCNE definition of Pharmaceutical Care" reading: "Pharmaceutical Care is the pharmacist's contribution to the care of individuals in order to optimize medicines use and improve health outcomes". It was possible to paraphrase definitions of PhC using a standardised syntax focusing on the provider, recipient, subject, outcomes, and activities included in PhC practice. During a one-day workshop, experts in PhC research agreed on a definition, intended to be applicable for the

  3. 40 CFR 61.21 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... dose equivalent and the definition of reference man are outlined in the International Commission on... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Definitions. 61.21 Section 61.21... Underground Uranium Mines § 61.21 Definitions. As used in this subpart, all terms not defined here have the...

  4. 48 CFR 370.203 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Definitions. 370.203... Opportunities 370.203 Definitions. For purposes of this Subpart 370.2, the following definitions shall apply: (a... Financing Act of 1974 (88 Stat. 77, 25 U.S.C. 1451). (d) Indian-owned economic enterprise means any Indian...

  5. 12 CFR 404.13 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Definitions. 404.13 Section 404.13 Banks and Banking EXPORT-IMPORT BANK OF THE UNITED STATES INFORMATION DISCLOSURE Access to Records Under the Privacy Act of 1974 § 404.13 Definitions. For purposes of this subpart, the following definitions shall apply...

  6. 36 CFR 219.36 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... Forest System Land and Resource Management Planning Definitions § 219.36 Definitions. Definitions of the... vision for a specific area of land or type of land within the plan area. Statements of desired conditions... species of plants or animals which are not indigenous to an area but valued for their contribution to...

  7. 20 CFR 229.2 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... MINIMUM GUARANTEE General § 229.2 Definitions. The following definitions are used in this part: Annuity... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Definitions. 229.2 Section 229.2 Employees... average wages of all wage earners from 1951 although the second year before the year the worker dies or...

  8. Predictable Technique to Register Retruded Contact Position (RCP) Using a Disposable Jaw Relation Recording Device.

    Science.gov (United States)

    Daher, Tony; Lobel, William A; Massad, Joseph; Ahuja, Swati; Danilov, Zarko Jack

    2015-05-01

    The dental literature presents various definitions and techniques to describe and register centric relation (CR) or centric occlusion (CO). Briefly reviewing the literature in relation to CR, this article proposes the use of the term retruded contact position (RCP), clinically defined as retruded, unstrained, repeatable position and where the mandibular movements start when a Gothic arch tracing is used. With this clinical definition, a technique can be easily selected that meets all the requirements of such position. The article discusses the use of a jaw recorder that is an intraorally graphic recording device that results in a tracing of mandibular movements in one plane, with the apex of the tracing indicating the retruded, unstrained, and repeatable relationship. The intersection of the arcs produced by the right and left working movement form the apex of the Gothic arch tracing. Several clinical situations using the jaw recorder are described. Clinicians can now quickly and accurately record RCP, balance complete, partial, or implant dentures, and orthopedically reposition the mandible. The technique achieves highly reliable and reproducible results.

  9. Introducing the religio-centric positional advantage to Indonesian small businesses

    Directory of Open Access Journals (Sweden)

    Hendar Hendar

    2017-03-01

    Full Text Available With a focus on small religion-based businesses in Indonesia, this research examines whether marketing innovativeness, customers responsiveness and competitors′ responsiveness can improve marketing performance. A conceptual model on the correlation of these three variables with religio-centric positional advantage and marketing performance is examined by using structural equation model. For this purpose 335 small businesses of Islamic Fashion had been studied using purposive sampling from 11 regencies/cities in Central Java (Indonesia. The results showed that (1 small companies in these market segments based on religion is likely to have better marketing performance when they have the Religio-centric positional advantage, (2 The increase in marketing innovativeness, CuR and CoR is required to improve and maintain religio-centric positional advantage, and (3 religio-centric positional advantage is definitely a mediator in the correlation of marketing innovativeness, customer responsiveness and competitors responsiveness with marketing performance.

  10. On the extreme value statistics of normal random matrices and 2D Coulomb gases: Universality and finite N corrections

    Science.gov (United States)

    Ebrahimi, R.; Zohren, S.

    2018-03-01

    In this paper we extend the orthogonal polynomials approach for extreme value calculations of Hermitian random matrices, developed by Nadal and Majumdar (J. Stat. Mech. P04001 arXiv:1102.0738), to normal random matrices and 2D Coulomb gases in general. Firstly, we show that this approach provides an alternative derivation of results in the literature. More precisely, we show convergence of the rescaled eigenvalue with largest modulus of a normal Gaussian ensemble to a Gumbel distribution, as well as universality for an arbitrary radially symmetric potential. Secondly, it is shown that this approach can be generalised to obtain convergence of the eigenvalue with smallest modulus and its universality for ring distributions. Most interestingly, the here presented techniques are used to compute all slowly varying finite N correction of the above distributions, which is important for practical applications, given the slow convergence. Another interesting aspect of this work is the fact that we can use standard techniques from Hermitian random matrices to obtain the extreme value statistics of non-Hermitian random matrices resembling the large N expansion used in context of the double scaling limit of Hermitian matrix models in string theory.

  11. 10 CFR 715.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Definitions. 715.2 Section 715.2 Energy DEPARTMENT OF ENERGY DEFINITION OF NON-RECOURSE PROJECT-FINANCED § 715.2 Definitions. As used in this subpart— Act means the Clean Air Act Amendments of 1990, 104 Stat. 2399. Facility means a “new independent power...

  12. 44 CFR 71.2 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... as by a private sector insurance company under the Write Your Own Program as authorized by 44 CFR... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Definitions. 71.2 Section 71... LEGISLATION § 71.2 Definitions. (a) Except as otherwise provided in this part, the definitions set forth in...

  13. ITER definition phase

    International Nuclear Information System (INIS)

    1989-01-01

    The International Thermonuclear Experimental Reactor (ITER) is envisioned as a fusion device which would demonstrate the scientific and technological feasibility of fusion power. As a first step towards achieving this goal, the European Community, Japan, the Soviet Union, and the United States of America have entered into joint conceptual design activities under the auspices of the International Atomic Energy Agency. A brief summary of the Definition Phase of ITER activities is contained in this report. Included in this report are the background, objectives, organization, definition phase activities, and research and development plan of this endeavor in international scientific collaboration. A more extended technical summary is contained in the two-volume report, ''ITER Concept Definition,'' IAEA/ITER/DS/3. 2 figs, 2 tabs

  14. 40 CFR 279.1 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Definitions. 279.1 Section 279.1... THE MANAGEMENT OF USED OIL Definitions § 279.1 Definitions. Terms that are defined in §§ 260.10, 261.1... may also accept used oil from household do-it-yourselfers. Used oil fuel marketer means any person who...

  15. 21 CFR 516.13 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Definitions. 516.13 Section 516.13 Food and Drugs... Minor Species New Animal Drug § 516.13 Definitions. The following definitions of terms apply only in the... treatment, control or prevention of a disease or condition, or the intention to affect the structure or...

  16. Genomic definition of species

    Energy Technology Data Exchange (ETDEWEB)

    Crkvenjakov, R.; Drmanac, R.

    1991-07-01

    The subject of this paper is the definition of species based on the assumption that genome is the fundamental level for the origin and maintenance of biological diversity. For this view to be logically consistent it is necessary to assume the existence and operation of the new law which we call genome law. For this reason the genome law is included in the explanation of species phenomenon presented here even if its precise formulation and elaboration are left for the future. The intellectual underpinnings of this definition can be traced to Goldschmidt. We wish to explore some philosophical aspects of the definition of species in terms of the genome. The point of proposing the definition on these grounds is that any real advance in evolutionary theory has to be correct in both its philosophy and its science.

  17. Diagnosing acute respiratory distress syndrome in resource limited settings: the Kigali modification of the Berlin definition.

    Science.gov (United States)

    Riviello, Elisabeth D; Buregeya, Egide; Twagirumugabe, Theogene

    2017-02-01

    The acute respiratory distress syndrome (ARDS) was re-defined by a panel of experts in Berlin in 2012. Although the Berlin criteria improved upon the validity and reliability of the definition, it did not make diagnosis of ARDS in resource limited settings possible. Mechanical ventilation, arterial blood gas measurements, and chest radiographs are not feasible in many regions of the world. In 2014, we proposed and applied the Kigali modification of the Berlin definition in a hospital in Rwanda. This review synthesizes literature from the last 18 months relevant to the Kigali modification. In the last 18 months, the need for a universally applicable ARDS definition was reinforced by advances in supportive care that can be implemented in resource poor settings. Research demonstrating the variable impact of positive end expiratory pressure on hypoxemia, the validity of using pulse oximetry rather than arterial blood gas to categorize hypoxemia, and the accuracy of lung ultrasound support the use of the Kigali modification of the Berlin definition. Studies directly comparing the Berlin definition to the Kigali modification are needed. Ongoing clinical research on ARDS needs to include low-income countries.

  18. Existence and uniqueness of positive solutions for a nonlocal dispersal population model

    Directory of Open Access Journals (Sweden)

    Jian-Wen Sun

    2014-06-01

    Full Text Available In this article, we study the solutions of a nonlocal dispersal equation with a spatial weight representing competitions and aggregation. To overcome the limitations of comparison principles, we introduce new definitions of upper-lower solutions. The proof of existence and uniqueness of positive solutions is based on the method of monotone iteration sequences.

  19. Asympotics with positive cosmological constant

    Science.gov (United States)

    Bonga, Beatrice; Ashtekar, Abhay; Kesavan, Aruna

    2014-03-01

    Since observations to date imply that our universe has a positive cosmological constant, one needs an extension of the theory of isolated systems and gravitational radiation in full general relativity from the asymptotically flat to asymptotically de Sitter space-times. In current definitions, one mimics the boundary conditions used in asymptotically AdS context to conclude that the asymptotic symmetry group is the de Sitter group. However, these conditions severely restricts radiation and in fact rules out non-zero flux of energy, momentum and angular momentum carried by gravitational waves. Therefore, these formulations of asymptotically de Sitter space-times are uninteresting beyond non-radiative spacetimes. The situation is compared and contrasted with conserved charges and fluxes at null infinity in asymptotically flat space-times.

  20. Toward a Definition of the Engineering Method.

    Science.gov (United States)

    Koen, Billy V.

    1988-01-01

    Describes a preliminary definition of engineering method as well as a definition and examples of engineering heuristics. After discussing some alternative definitions of the engineering method, a simplified definition of the engineering method is suggested. (YP)

  1. Late HIV Diagnosis: Proposed Common Definitions and Associations With Short-Term Mortality.

    Science.gov (United States)

    Jiang, Hongbo; Xie, Nianhua; Liu, Jianhua; Zhang, Zhixia; Liu, Li; Yao, Zhongzhao; Wang, Xia; Nie, Shaofa

    2015-09-01

    The aim of this study was to present a definition of late presentation according to different time periods between initial diagnosis of human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) diagnosis which would reliably identify individuals with high risk of mortality within 1 year of diagnosis, and could be used as a suggested common definition.Data of individuals diagnosed from 1994 to February 2012 in Wuhan, China were extracted retrospectively from the national HIV surveillance system. Four time periods (1, 3, 6, and 12 months) combined with the European consensus definition of advanced HIV disease (AHD) were compared. The predictive ability of each definition for identifying an individual who died within 1 year after HIV diagnosis was assessed.A total of 980 patients were included, of whom 289 (29.49%), 324 (33.06%), 353 (36.02%), and 387 (39.49%) were defined as AHD according to the definition of a CD4 count AIDS-defining event (ADE) within 1, 3, 6, and 12 months of HIV diagnosis, respectively. One hundred twenty-seven (12.96%) patients died within 1 year of diagnosis. The highest Youden's index and largest area under the curve were presented in time period within 3 months. Time period within 1 month presented the highest consistency rate, positive likelihood ratio, and kappa value. Longer time periods increased the sensitivity but decreased the specificity.Given the European consensus definitions and the current results, we suggested that AHD could be defined as "a first-reported CD4 count <200 cells/μL or an ADE within 1 month after HIV diagnosis." "Late presentation" could be defined as "a first-reported CD4 count <350 cells/μL or an ADE within 1 month after HIV diagnosis."

  2. Clinical case definition and manifestations of paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome.

    Science.gov (United States)

    Manosuthi, Weerawat; Van Tieu, Hong; Mankatitham, Wiroj; Lueangniyomkul, Aroon; Ananworanich, Jintanat; Avihingsanon, Anchalee; Siangphoe, Umaporn; Klongugkara, Sukonsri; Likanonsakul, Sirirat; Thawornwan, Unchana; Suntisuklappon, Bussakorn; Sungkanuparph, Somnuek

    2009-11-27

    The International Network for the Study of HIV-associated IRIS (INSHI) recently published criteria for tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) diagnosis. The performance of this definition and clinical manifestations of TB-IRIS were studied. Antiretroviral therapy-naive HIV/TB Thai patients receiving antituberculous therapy were enrolled during 2006-2007 and prospectively followed through 24 weeks of antiretroviral therapy. Patients were defined as having paradoxical TB-IRIS if they fulfilled the 'study definition' by French 2004 and were confirmed by an external reviewer. All were later compared by the classification according to 'INSHI-2008'. For the 126 patients, median baseline CD4 cell count was 43 cells/microl and HIV-1 RNA was 5.9 log(10) Y copies/ml. Seventy-three (58%) had extrapulmonary/disseminated TB. Twenty-two (18%) and 21 (17%) fulfilled TB-IRIS criteria according to the study definition and INSHI-2008 definition, respectively. Two (2%) were diagnosed by study definition only and one (1%) by INSHI-2008 definition only. Twenty (16%) were concordantly diagnosed by both definitions and 103 (82%) were consistently negative. Eighteen (82%) had worsening of a preexisting site, whereas four (18%) had TB-IRIS in a new location. Lymph node enlargement (73%) and fever (59%) were common in TB-IRIS. Sensitivity and specificity of INSHI-2008 was 91% (95% confidence interval, 72-98%) and 99% (95% confidence interval, 95-99.8%), respectively. Positive predictive value was 95% and negative predictive value was 98%. By multivariate analysis, factors predicting TB-IRIS were extrapulmonary TB (odds ratio, 8.63) and disseminated TB (odds ratio, 4.17). There was high concordance between the INSHI-2008 and French 2004 definition for TB-IRIS diagnosis in HIV/TB patients with relatively high rate of paradoxical TB-IRIS. This suggests that lack of HIV-1 RNA and CD4 cell count monitoring does not impede the ability to diagnose TB-IRIS.

  3. High-Definition Medicine.

    Science.gov (United States)

    Torkamani, Ali; Andersen, Kristian G; Steinhubl, Steven R; Topol, Eric J

    2017-08-24

    The foundation for a new era of data-driven medicine has been set by recent technological advances that enable the assessment and management of human health at an unprecedented level of resolution-what we refer to as high-definition medicine. Our ability to assess human health in high definition is enabled, in part, by advances in DNA sequencing, physiological and environmental monitoring, advanced imaging, and behavioral tracking. Our ability to understand and act upon these observations at equally high precision is driven by advances in genome editing, cellular reprogramming, tissue engineering, and information technologies, especially artificial intelligence. In this review, we will examine the core disciplines that enable high-definition medicine and project how these technologies will alter the future of medicine. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. An automated database case definition for serious bleeding related to oral anticoagulant use.

    Science.gov (United States)

    Cunningham, Andrew; Stein, C Michael; Chung, Cecilia P; Daugherty, James R; Smalley, Walter E; Ray, Wayne A

    2011-06-01

    Bleeding complications are a serious adverse effect of medications that prevent abnormal blood clotting. To facilitate epidemiologic investigations of bleeding complications, we developed and validated an automated database case definition for bleeding-related hospitalizations. The case definition utilized information from an in-progress retrospective cohort study of warfarin-related bleeding in Tennessee Medicaid enrollees 30 years of age or older. It identified inpatient stays during the study period of January 1990 to December 2005 with diagnoses and/or procedures that indicated a current episode of bleeding. The definition was validated by medical record review for a sample of 236 hospitalizations. We reviewed 186 hospitalizations that had medical records with sufficient information for adjudication. Of these, 165 (89%, 95%CI: 83-92%) were clinically confirmed bleeding-related hospitalizations. An additional 19 hospitalizations (10%, 7-15%) were adjudicated as possibly bleeding-related. Of the 165 clinically confirmed bleeding-related hospitalizations, the automated database and clinical definitions had concordant anatomical sites (gastrointestinal, cerebral, genitourinary, other) for 163 (99%, 96-100%). For those hospitalizations with sufficient information to distinguish between upper/lower gastrointestinal bleeding, the concordance was 89% (76-96%) for upper gastrointestinal sites and 91% (77-97%) for lower gastrointestinal sites. A case definition for bleeding-related hospitalizations suitable for automated databases had a positive predictive value of between 89% and 99% and could distinguish specific bleeding sites. Copyright © 2011 John Wiley & Sons, Ltd.

  5. Decoherence of odd compass states in the phase-sensitive amplifying/dissipating environment

    Energy Technology Data Exchange (ETDEWEB)

    Dodonov, V.V., E-mail: vdodonov@fis.unb.br [Instituto de Física, Universidade de Brasília, Caixa Postal 04455, 70919-970 Brasília, DF (Brazil); Valverde, C. [Unidade de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, BR 153, km 98, 75001-970 Anápolis, GO (Brazil); Universidade Paulista, BR 153, km 7, 74845-090 Goiânia, GO (Brazil); Souza, L.S. [Unidade de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, BR 153, km 98, 75001-970 Anápolis, GO (Brazil); Baseia, B. [Instituto de Física, Universidade Federal de Goiás, 74.690-900 Goiânia, GO (Brazil); Departamento de Física, Universidade Federal da Paraíba, 58.051-970 João Pessoa, PB (Brazil)

    2016-08-15

    We study the evolution of odd compass states (specific superpositions of four coherent states), governed by the standard master equation with phase-sensitive amplifying/attenuating terms, in the presence of a Hamiltonian describing a parametric degenerate linear amplifier. Explicit expressions for the time-dependent Wigner function are obtained. The time of disappearance of the so called “sub-Planck structures” is calculated using the negative value of the Wigner function at the origin of phase space. It is shown that this value rapidly decreases during a short “conventional interference degradation time” (CIDT), which is inversely proportional to the size of quantum superposition, provided the anti-Hermitian terms in the master equation are of the same order (or stronger) as the Hermitian ones (governing the parametric amplification). The CIDT is compared with the final positivization time (FPT), when the Wigner function becomes positive. It appears that the FPT does not depend on the size of superpositions, moreover, it can be much bigger in the amplifying media than in the attenuating ones. Paradoxically, strengthening the Hamiltonian part results in decreasing the CIDT, so that the CIDT almost does not depend on the size of superpositions in the asymptotical case of very weak reservoir coupling. We also analyze the evolution of the Mandel factor, showing that for some sets of parameters this factor remains significantly negative, even when the Wigner function becomes positive.

  6. The Montreux definition of neonatal ARDS: biological and clinical background behind the description of a new entity.

    Science.gov (United States)

    De Luca, Daniele; van Kaam, Anton H; Tingay, David G; Courtney, Sherry E; Danhaive, Olivier; Carnielli, Virgilio P; Zimmermann, Luc J; Kneyber, Martin C J; Tissieres, Pierre; Brierley, Joe; Conti, Giorgio; Pillow, Jane J; Rimensberger, Peter C

    2017-08-01

    Acute respiratory distress syndrome (ARDS) is undefined in neonates, despite the long-standing existing formal recognition of ARDS syndrome in later life. We describe the Neonatal ARDS Project: an international, collaborative, multicentre, and multidisciplinary project which aimed to produce an ARDS consensus definition for neonates that is applicable from the perinatal period. The definition was created through discussions between five expert members of the European Society for Paediatric and Neonatal Intensive Care; four experts of the European Society for Paediatric Research; two independent experts from the USA and two from Australia. This Position Paper provides the first consensus definition for neonatal ARDS (called the Montreux definition). We also provide expert consensus that mechanisms causing ARDS in adults and older children-namely complex surfactant dysfunction, lung tissue inflammation, loss of lung volume, increased shunt, and diffuse alveolar damage-are also present in several critical neonatal respiratory disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. On the structural position of non-peripheral adjunct clauses

    Directory of Open Access Journals (Sweden)

    Maria Lobo

    2002-06-01

    Full Text Available This paper is concerned with the structural position occupied by a subset of adjunct clauses, namely those which can occur in final position without a special intonational break. After a definition of the structures to be considered, it will be shown that the classical assumption according to which they are generated as adjuncts is empirically superior to the adjunct-as-complement analysis (cf. Larson 1988; 1990, and to more recent analyses, which follow an antisymmetric framework (cf. Kayne 1994. It will also be shown that a base generation account of preverbal adverbial clauses is to be preferred over a movement analysis on the basis of empirical data, and in conformity with theoretical economy assumptions (Merge over Move.

  8. Power: towards a third generation definition

    OpenAIRE

    13250612 - Zaaiman, Stephanus Johannes

    2008-01-01

    Power is a well-established concept in the social sciences especially in the political sciences. Although it is widely used in scientific discourse, different definitions and perspectives prevail with regard to it. This article aims to explore the possibilities of taking the debate further towards a third generation definition of social power. Although first generation definitions (associated with Weber and Dahl) and second generation definitions (associated with inter alia Giddens and Morris...

  9. Definition of postprandial lipaemia

    DEFF Research Database (Denmark)

    Kolovou, Genovefa D; Mikhailidis, Dimitri P; Nordestgaard, Børge G

    2011-01-01

    At the present time, there is no widely agreed definition of postprandial lipaemia (PPL). This lack of a shared definition limits the identification and treatment of patients with exaggerated PPL as well as the evaluation of potential therapeutic agents. PPL is a complex syndrome characterized by...

  10. PT symmetry and a dynamical realization of the SU(1, 1) algebra

    Science.gov (United States)

    Banerjee, Rabin; Mukherjee, Pradip

    2016-01-01

    We show that the elementary modes of the planar harmonic oscillator can be quantized in the framework of quantum mechanics based on pseudo-hermitian Hamiltonians. These quantized modes are demonstrated to act as dynamical structures behind a new Jordan-Schwinger realization of the SU(1, 1) algebra. This analysis complements the conventional Jordan-Schwinger construction of the SU(2) algebra based on hermitian Hamiltonians of a doublet of oscillators.

  11. Nursing Delegation to Unlicensed Assistive Personnel in the School Setting. Position Statement. Revised

    Science.gov (United States)

    Cagginello, Joan; Blackborow, Mary; Porter, Jessica; Disney, Jody; Andresen, Kathleen; Tuck, Christine

    2014-01-01

    It is the position of the National Association of School Nurses (NASN) that the delegation of nursing tasks in the school setting can be a valuable tool for the registered professional school nurse (hereinafter referred to as school nurse), when based on the nursing definition of delegation (American Nurses Association [ANA], 2012) and in…

  12. Sensitivity Analyses of Alternative Methods for Disposition of High-Level Salt Waste: A Position Statement

    International Nuclear Information System (INIS)

    Harris, S.P.; Tuckfield, R.C.

    1998-01-01

    This position paper provides the approach and detail pertaining to a sensitivity analysis for the Phase II definition of weighted evaluation criteria weights and utility function values on the total utility scores for each Initial List alternative due to uncertainty and bias in engineering judgment

  13. The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria.

    Science.gov (United States)

    Parvizi, Javad; Tan, Timothy L; Goswami, Karan; Higuera, Carlos; Della Valle, Craig; Chen, Antonia F; Shohat, Noam

    2018-05-01

    The introduction of the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection (PJI) in 2011 resulted in improvements in diagnostic confidence and research collaboration. The emergence of new diagnostic tests and the lessons we have learned from the past 7 years using the MSIS definition, prompted us to develop an evidence-based and validated updated version of the criteria. This multi-institutional study of patients undergoing revision total joint arthroplasty was conducted at 3 academic centers. For the development of the new diagnostic criteria, PJI and aseptic patient cohorts were stringently defined: PJI cases were defined using only major criteria from the MSIS definition (n = 684) and aseptic cases underwent one-stage revision for a noninfective indication and did not fail within 2 years (n = 820). Serum C-reactive protein (CRP), D-dimer, erythrocyte sedimentation rate were investigated, as well as synovial white blood cell count, polymorphonuclear percentage, leukocyte esterase, alpha-defensin, and synovial CRP. Intraoperative findings included frozen section, presence of purulence, and isolation of a pathogen by culture. A stepwise approach using random forest analysis and multivariate regression was used to generate relative weights for each diagnostic marker. Preoperative and intraoperative definitions were created based on beta coefficients. The new definition was then validated on an external cohort of 222 patients with PJI who subsequently failed with reinfection and 200 aseptic patients. The performance of the new criteria was compared to the established MSIS and the prior International Consensus Meeting definitions. Two positive cultures or the presence of a sinus tract were considered as major criteria and diagnostic of PJI. The calculated weights of an elevated serum CRP (>1 mg/dL), D-dimer (>860 ng/mL), and erythrocyte sedimentation rate (>30 mm/h) were 2, 2, and 1 points, respectively. Furthermore, elevated

  14. Evaluation of an expanded case definition for vaccine-modified measles in a school outbreak in South Korea in 2010.

    Science.gov (United States)

    Choe, Young June; Hu, Jae Kyung; Song, Kyung Min; Cho, Heeyeon; Yoon, Hee Sook; Kim, Seung Tae; Lee, Han Jung; Kim, Kisoon; Bae, Geun-Ryang; Lee, Jong-Koo

    2012-01-01

    In this study, we have described the clinical characteristics of vaccine-modified measles to assess the performance of an expanded case definition in a school outbreak that occurred in 2010. The sensitivity, specificity, and the positive and negative predictive values were evaluated. Among 74 cases of vaccine-modified measles, 47 (64%) met the original case definition. Fever and rash were observed in 73% (54/74); fever was the most common (96%, 71/74) presenting symptom, and rash was noted in 77% (57/74) of the cases. The original case definition showed an overall sensitivity of 63.5% and a specificity of 100.0%. The expanded case definition combining fever and rash showed a higher sensitivity (72.9%) but a lower specificity (88.2%) than the original. The presence of fever and one or more of cough, coryza, or conjunctivitis scored the highest sensitivity among the combinations of signs and symptoms (77.0%), but scored the lowest specificity (52.9%). The expanded case definition was sensitive in identifying suspected cases of vaccine-modified measles. We suggest using this expanded definition for outbreak investigation in a closed community, and consider further discussions on expanding the case definition of measles for routine surveillance in South Korea.

  15. A geometric form of the canonical commutation

    International Nuclear Information System (INIS)

    Guz, W.

    1987-01-01

    Some aspects of a geometric approach to quantum theory, in which the quantum-mechanical position and momentum operators are represented by covariant derivatives, are here developed. Here, the previously estabilished formalism of Caianiello and his co-workers is extended to the case of an integrable almost complex Hermitian manifold. The general theory is then applied to the two-dimensional case, where the structure of the 'quantum geometry' induced in the manifold by the quantum-mechanical CCR can be explicitly determined

  16. Definitive diagnosis of breast implant rupture using magnetic resonance imaging.

    Science.gov (United States)

    Ahn, C Y; Shaw, W W; Narayanan, K; Gorczyca, D P; Sinha, S; Debruhl, N D; Bassett, L W

    1993-09-01

    Breast implant rupture is an important complication of augmented and reconstructed breasts. Although several techniques such as mammography, xeromammography, ultrasound, thermography, and computed tomographic (CT) scanning have been proven to be useful to detect implant rupture, they have several disadvantages and lack specificity. In the current study, we have established magnetic resonance imaging (MRI) as a definitive, reliable, and reproducible technique to diagnose both intracapsular and extracapsular ruptures. The study was conducted in 100 symptomatic patients. Our imaging parameters were able to identify ruptures in implants with silicone shells. All the ruptures showed the presence of wavy lines, free-floating silicone shell within the gel ("free-floating loose-thread sign" or "linguine sign"). We had a 3.75 percent incidence of false-positive and false-negative results. The sensitivity for detection of silicone implant rupture was 76 percent, with a specificity of 97 percent. In addition, we also were able to identify the artifacts that may interfere with the definitive diagnosis of implant rupture.

  17. Productivity of Stream Definitions

    NARCIS (Netherlands)

    Endrullis, Jörg; Grabmayer, Clemens; Hendriks, Dimitri; Isihara, Ariya; Klop, Jan

    2007-01-01

    We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continuously in such a way that a uniquely determined stream is obtained as the limit. Whereas productivity is undecidable

  18. Productivity of stream definitions

    NARCIS (Netherlands)

    Endrullis, J.; Grabmayer, C.A.; Hendriks, D.; Isihara, A.; Klop, J.W.

    2008-01-01

    We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continually in such a way that a uniquely determined stream in constructor normal form is obtained as the limit. Whereas

  19. Optimal sum rules inequalities for spin 1/2 Compton scattering

    International Nuclear Information System (INIS)

    Guiasu, I.; Radescu, E.E.; Razillier, I.

    1979-08-01

    A formalism appropriate for model independent dispersion theoretic investigations of the (not necessarily forward) Compton scattering off spin 1/2 hadronic targets, which fully exploits the analyticity properties of the amplitudes (to lowest order in electromagnetism) in ν 2 at fixed t(ν=(s-u)/4) s,t,u = Mandelstam variables), is developed. It relies on methods which are specific to boundary value problems for analytic matrix-valued functions. An analytic factorization of the positive definite hermitian matrix associated with the bilinear expression of the unpolarized differential cross section (u.d.c.s.) in terms of the Bardeen-Tung (B.T.) invariant amplitudes is explicitly obtained. For t in a specified portion of the physical region, six new amplitudes describing the process are thereby constructed which have the same good analyticity structure in ν 2 as the (crossing symmetrized) B.T. amplitudes, while their connection with the usual helicity amplitudes is given by a matrix which is unitary on the unitarity cut. A bound on a certain integral over the u.d.c.s. above the first inelastic threshold, established in terms of the target's charge and anomalous magnetic moment, improves a previous weaker result, being now optimal under the information accepted as known. (author)

  20. Urban Geographies, Art, and Collective Memories: the Chilean Centenary and the Definition of Place

    Directory of Open Access Journals (Sweden)

    Gloria Cortés Aliaga

    2010-07-01

    Full Text Available The identification metaphors during the celebration of the independence centenary in Chile were defined by partisan discourses, access to modernity, and opposition to the political, cultural, and social system originated during the nineteenth century. On the one hand, this territorial definition gave place to a rhetoric of landscape according to a social critique containing the paradigms of time and space. On the other hand, it fostered the definition of spaces of power, where festivities, popular activities, and the erection  of monuments delimit territorial politics and the symbolic construction of Chilean oligarchy. Reading these expressions would explain the position occupied by social subjects and their territorial affirmation after 1910.

  1. Simulation of statistical systems with not necessarily real and positive probabilities

    International Nuclear Information System (INIS)

    Kalkreuter, T.

    1991-01-01

    A new method to determine expectation values of observables in statistical systems with not necessarily real and positive probabilities is proposed. It is tested in a numerical study of the two-dimensional O(3)-symmetric nonlinear σ-model with Symanzik's one-loop improved lattice action. This model is simulated as polymer system with field dependent activities which can be made positive definite or indefinite by adjusting additive constants of the action. For a system with indefinite activities the new proposal is found to work. It is also verified that local observables are not affected by far-away ploymers with indefinite activities when the system has no long-range order. (orig.)

  2. 42 CFR 435.530 - Definition of blindness.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Definition of blindness. 435.530 Section 435.530... ISLANDS, AND AMERICAN SAMOA Categorical Requirements for Eligibility Blindness § 435.530 Definition of blindness. (a) Definition. The agency must use the same definition of blindness as used under SSI, except...

  3. Comparison of the Berlin definition with the American European consensus definition for acute respiratory distress syndrome in burn patients.

    Science.gov (United States)

    Bordes, Julien; Lacroix, Guillaume; Esnault, Pierre; Goutorbe, Philippe; Cotte, Jean; Dantzer, Eric; Meaudre, Eric

    2014-06-01

    Acute respiratory distress syndrome (ARDS) is a leading cause of mortality in burn patients. Smoke inhalation, pneumonia and inflammation process are the major causes of ARDS in burn patients. The American European Consensus Conference (AECC) definition proposed in 1994 has recently been revised by the Berlin definition. Our objective was to describe the epidemiology of ARDS comparing the Berlin definition with the AECC definition in a retrospective cohort of burn patients. We reviewed admitted burn adult patients for a two year period, and investigated patient who received mechanical ventilation for more than 48 h and in whom pneumonia was diagnosed. 40 patients were analyzed. According to the AECC definition, 11 patients met criteria for ALI (27.5%), and 29 patients for ARDS (72.5%). According to the Berlin definition, all patients met criteria for ARDS: 4 (10%) for a severe ARDS, 25 (62.5%) for a moderate ARDS, 11 (27.5%) for a mild ARDS. Inhalation injury was diagnosed in 10 patients (25%). Categorizing patients with the Berlin definition showed statistically significative difference of mortality within the three groups, but not with the AECC definition. The Berlin definition seems to be more accurate than the AECC definition to assess the severity of ARDS in term of outcome in burn patients. This definition may facilitate prompt recognition of ARDS in burn patients, and promote protective ventilation strategy to a larger number of patients. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  4. 19 CFR 122.1 - General definitions.

    Science.gov (United States)

    2010-04-01

    ... such government, or passengers traveling on official business of such government; or (3) Carrying... 19 Customs Duties 1 2010-04-01 2010-04-01 false General definitions. 122.1 Section 122.1 Customs... AIR COMMERCE REGULATIONS General Definitions and Provisions § 122.1 General definitions. The following...

  5. 20 CFR 633.104 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... FARMWORKER PROGRAMS Introductory Provisions § 633.104 Definitions. The following definitions are applicable... the criteria used by the Bureau of Labor Statistics of the Department in defining individuals as...

  6. Sensitivity, Specificity, and Public-Health Utility of Clinical Case Definitions Based on the Signs and Symptoms of Cholera in Africa.

    Science.gov (United States)

    Nadri, Johara; Sauvageot, Delphine; Njanpop-Lafourcade, Berthe-Marie; Baltazar, Cynthia S; Banla Kere, Abiba; Bwire, Godfrey; Coulibaly, Daouda; Kacou N'Douba, Adele; Kagirita, Atek; Keita, Sakoba; Koivogui, Lamine; Landoh, Dadja E; Langa, Jose P; Miwanda, Berthe N; Mutombo Ndongala, Guy; Mwakapeje, Elibariki R; Mwambeta, Jacob L; Mengel, Martin A; Gessner, Bradford D

    2018-04-01

    During 2014, Africa reported more than half of the global suspected cholera cases. Based on the data collected from seven countries in the African Cholera Surveillance Network (Africhol), we assessed the sensitivity, specificity, and positive and negative predictive values of clinical cholera case definitions, including that recommended by the World Health Organization (WHO) using culture confirmation as the gold standard. The study was designed to assess results in real-world field situations in settings with recent cholera outbreaks or endemicity. From June 2011 to July 2015, a total of 5,084 persons with suspected cholera were tested for Vibrio cholerae in seven different countries of which 35.7% had culture confirmation. For all countries combined, the WHO case definition had a sensitivity = 92.7%, specificity = 8.1%, positive predictive value = 36.1%, and negative predictive value = 66.6%. Adding dehydration, vomiting, or rice water stools to the case definition could increase the specificity without a substantial decrease in sensitivity. Future studies could further refine our findings primarily by using more sensitive methods for cholera confirmation.

  7. The HEALTHGRAIN definition of ‘whole grain’

    Science.gov (United States)

    van der Kamp, Jan Willem; Poutanen, Kaisa; Seal, Chris J.; Richardson, David P.

    2014-01-01

    Most cereal products, like white bread, pasta, and biscuits, are based on flour after removal of bran and germ, the two parts of grain kernels containing most of the dietary fibre and other bioactive components. In the past decade, consumers have been rediscovering whole grain-based products and the number of wholegrain products has increased rapidly. In most countries in Europe and worldwide, however, no legally endorsed definition of wholegrain flour and products exists. Current definitions are often incomplete, lacking descriptions of the included grains and the permitted flour manufacturing processes. The consortium of the HEALTHGRAIN EU project (FP6-514008, 2005–2010) identified the need for developing a definition of whole grain with the following scope: 1) more comprehensive than current definitions in most EU countries; 2) one definition for Europe – when possible equal to definitions outside Europe; 3) reflecting current industrial practices for production of flours and consumer products; 4) useful in the context of nutritional guidelines and for labelling purposes. The definition was developed in a range of discussion meetings and consultations and was launched in 2010 at the end of the HEALTHGRAIN project. The grains included are specified: a wide range of cereal grains from the Poaceae family, and the pseudo-cereals amaranth, buckwheat, quinoa, and wild rice. The definition also describes manufacturing processes allowed for producing wholegrain flours. This paper compares the HEALTHGRAIN definition with previous definitions, provides more comprehensive explanations than in the definition itself regarding the inclusion of specific grains, and sets out the permitted flour manufacturing processes. PMID:24505218

  8. 43 CFR 7.32 - Supplemental definitions.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Supplemental definitions. 7.32 Section 7... RESOURCES Department of the Interior Supplemental Regulations § 7.32 Supplemental definitions. For purposes of this subpart, the following definitions will be used: (a) Site of religious or cultural importance...

  9. 7 CFR 301.92-1 - Definitions.

    Science.gov (United States)

    2010-01-01

    ..., or field grown cycads, and tissue culture plants grown in vitro; and plants meeting the definition of... 7 Agriculture 5 2010-01-01 2010-01-01 false Definitions. 301.92-1 Section 301.92-1 Agriculture..., DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Phytophthora Ramorum § 301.92-1 Definitions...

  10. Systematic review of proposed definitions of nocturnal polyuria and population-based evidence of their diagnostic accuracy.

    Science.gov (United States)

    Olesen, Tine Kold; Denys, Marie-Astrid; Vande Walle, Johan; Everaert, Karel

    2018-02-06

    Background Evidence of diagnostic accuracy for proposed definitions of nocturnal polyuria is currently unclear. Purpose Systematic review to determine population-based evidence of the diagnostic accuracy of proposed definitions of nocturnal polyuria based on data from frequency-volume charts. Methods Seventeen pre-specified search terms identified 351 unique investigations published from 1990 to 2016 in BIOSIS, Embase, Embase Alerts, International Pharmaceutical Abstract, Medline, and Cochrane. Thirteen original communications were included in this review based on pre-specified exclusion criteria. Data were extracted from each paper regarding subject age, sex, ethnicity, health status, sample size, data collection methods, and diagnostic discrimination of proposed definitions including sensitivity, specificity, positive and negative predictive value. Results The sample size of study cohorts, participant age, sex, ethnicity, and health status varied considerably in 13 studies reporting on the diagnostic performance of seven different definitions of nocturnal polyuria using frequency-volume chart data from 4968 participants. Most study cohorts were small, mono-ethnic, including only Caucasian males aged 50 or higher with primary or secondary polyuria that were compared to a control group of healthy men without nocturia in prospective or retrospective settings. Proposed definitions had poor discriminatory accuracy in evaluations based on data from subjects independent from the original study cohorts with findings being similar regarding the most widely evaluated definition endorsed by ICS. Conclusions Diagnostic performance characteristics for proposed definitions of nocturnal polyuria show poor to modest discrimination and are not based on sufficient level of evidence from representative, multi-ethnic population-based data from both females and males of all adult ages.

  11. 42 CFR 436.530 - Definition of blindness.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Definition of blindness. 436.530 Section 436.530... Requirements for Medicaid Eligibility Blindness § 436.530 Definition of blindness. (a) Definition. The agency must use the definition of blindness that is used in the State plan for AB or AABD. (b) State plan...

  12. 31 CFR 0.103 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... RULES OF CONDUCT General Provisions § 0.103 Definitions. The following definitions are used throughout... Comptroller of the Currency; (10) Office of the Inspector General; (11) Office of Thrift Supervision; (12...

  13. Dynamics of Situation Definition

    Science.gov (United States)

    Park, Dongseop; Moro, Yuji

    2006-01-01

    Situation definition is the process and product of actors' interpretive activities toward a given situation. By reviewing a number of psychological studies conducted in experimental settings, we found that the studies have only explicated a part of the situation definition process and have neglected its dynamic aspects. We need to focus on the…

  14. The significance of a uniform definition of pathological lymph nodes in Hodgkin lymphoma: Impact of different thresholds for positive lymph nodes in CT imaging on staging and therapy

    International Nuclear Information System (INIS)

    Vorwerk, Hilke; Obenauer, Silvia; Schmidberger, Heinz; Hess, Clemens F.; Weiss, Elisabeth

    2008-01-01

    Background and Purpose: The most commonly used approach for the assessment for differentiating malignant versus reactive lymph nodes is the measurement of the cross-section diameter of the lymph nodes in the transversal CT-planes. The intention of this article is to assess the impact of varying definitions of pathological lymph node size in CT-imaging in patients with Hodgkin lymphoma and to evaluate its effect on staging, chemotherapy regimes and radiation field size. Materials and methods: Pretherapeutic CT-scans of 10 consecutive patients with Hodgkin lymphoma have been evaluated based on two different definitions for malignant lymph node size; the classification of the German study group for Hodgkin lymphoma (1.0 cm) and the classification according to the results of the Cotswold consensus meeting 1989 (1.5 cm). Results: Applying the definitions of the DHSG and the Cotswold meeting we found more affected lymph node regions compared to the evaluation of the referring institutions in 9/10 and 6/10 patients, higher stages in 2/10 and 1/10 patients, more intense chemotherapy regimes in 3/10 and 1/10 and larger radiation fields in 10/10 and 6/10 patients, respectively. Conclusions: Varying definitions of pathologic lymph node size and inconsequent application of definitions reduce the comparability between different studies and within each study

  15. The brachistochrone problem in open quantum systems

    International Nuclear Information System (INIS)

    Rotter, Ingrid

    2007-01-01

    Recently, the quantum brachistochrone problem has been discussed in the literature by using non-Hermitian Hamilton operators of different types. Here, it is demonstrated that the passage time is tunable in realistic open quantum systems due to the biorthogonality of the eigenfunctions of the non-Hermitian Hamilton operator. As an example, the numerical results obtained by Bulgakov et al for the transmission through microwave cavities of different shapes are analyzed from the point of view of the brachistochrone problem. The passage time is shortened in the crossover from the weak-coupling to the strong-coupling regime where the resonance states overlap and many branch points (exceptional points) in the complex plane exist. The effect can not be described in the framework of the standard quantum mechanics with the Hermitian Hamilton operator and consideration of S matrix poles

  16. Parity-Time Symmetric Photonics

    KAUST Repository

    Zhao, Han

    2018-01-17

    The establishment of non-Hermitian quantum mechanics (such as parity-time (PT) symmetry) stimulates a paradigmatic shift for studying symmetries of complex potentials. Owing to the convenient manipulation of optical gain and loss in analogy to the complex quantum potentials, photonics provides an ideal platform for visualization of many conceptually striking predictions from the non-Hermitian quantum theory. A rapidly developing field has emerged, namely, PT symmetric photonics, demonstrating intriguing optical phenomena including eigenstate coalescence and spontaneous PT symmetry breaking. The advance of quantum physics, as the feedback, provides photonics with brand-new paradigms to explore the entire complex permittivity plane for novel optical functionalities. Here, we review recent exciting breakthroughs in PT symmetric photonics while systematically presenting their underlying principles guided by non-Hermitian symmetries. The potential device applications for optical communication and computing, bio-chemical sensing, and healthcare are also discussed.

  17. 26 CFR 1.801-1 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... TAXES Life Insurance Companies § 1.801-1 Definitions. (a) Life insurance company. The term life.... For the definition of an “insurance company”, see paragraph (b) of this section. In determining... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Definitions. 1.801-1 Section 1.801-1 Internal...

  18. Exotic quantum holonomy and higher-order exceptional points in quantum kicked tops

    OpenAIRE

    Tanaka, Atushi; Kim, Sang Wook; Cheon, Taksu

    2014-01-01

    The correspondence between exotic quantum holonomy that occurs in families of Hermitian cycles, and exceptional points (EPs) for non-Hermitian quantum theory is examined in quantum kicked tops. Under a suitable condition, an explicit expressions of the adiabatic parameter dependencies of quasienergies and stationary states, which exhibit anholonomies, are obtained. It is also shown that the quantum kicked tops with the complexified adiabatic parameter have a higher order EP, which is broken i...

  19. From a world-sheet supersymmetry to the Dirac equation

    International Nuclear Information System (INIS)

    Mankoc Borstnik, N.

    1991-10-01

    Starting from a classical action for a point particle with a local world-sheet supersymmetry, the Dirac equation follows with operators α-vector, β-vector γ-vector being defined in the Grassmann space as differential operators and having all the properties of the corresponding Dirac matrices except that α-vector and β-vector are anti-Hermitian rather than Hermitian. Such a particle interacts with an external field as expected. (author). 7 refs

  20. Pseudo-supersymmetry and the domain-wall/cosmology correspondence

    International Nuclear Information System (INIS)

    Skenderis, Kostas; Townsend, Paul K

    2007-01-01

    The correspondence between domain-wall and cosmological solutions of gravity coupled to scalar fields is explained. Any domain-wall solutions that admit a Killing spinor are shown to correspond to a cosmology that admits a pseudo-Killing spinor; whereas the Killing spinor obeys a Dirac-type equation with Hermitian 'mass'-matrix, the corresponding pseudo-Killing spinor obeys a Dirac-type equation with a anti-Hermitian 'mass'-matrix. We comment on some implications of (pseudo)supersymmetry

  1. Definitions of Health Terms: Minerals

    Science.gov (United States)

    ... gov/definitions/mineralsdefinitions.html Definitions of Health Terms : Minerals To use the sharing features on this page, ... National Institutes of Health, Office of Dietary Supplements Minerals Minerals are those elements on the earth and ...

  2. 40 CFR 195.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... PROFICIENCY PROGRAMS General Provisions § 195.2 Definitions. Definitions in 15 U.S.C. 2602 and 2662 apply to... exam means the exam which evaluates individuals who provide radon measurement services in a residential...

  3. Different definitions of CpG island methylator phenotype and outcomes of colorectal cancer: a systematic review.

    Science.gov (United States)

    Jia, Min; Gao, Xu; Zhang, Yan; Hoffmeister, Michael; Brenner, Hermann

    2016-01-01

    Contradictory results were reported for the prognostic role of CpG island methylator phenotype (CIMP) among colorectal cancer (CRC) patients. Differences in the definitions of CIMP were the most common explanation for these discrepancies. The aim of this systematic review was to give an overview of the published studies on CRC prognosis according to the different definitions of CIMP. A systematic literature search was performed in MEDLINE and ISI Web of Science for articles published until 3 April 2015. Data extraction included information about the study population, the definition of CIMP, and investigated outcomes. Thirty-six studies were included in this systematic review. Among them, 30 studies reported the association of CIMP and CRC prognosis and 11 studies reported the association of CIMP with survival after CRC therapy. Overall, 16 different definitions of CIMP were identified. The majority of studies reported a poorer prognosis for patients with CIMP-positive (CIMP+)/CIMP-high (CIMP-H) CRC than with CIMP-negative (CIMP-)/CIMP-low (CIMP-L) CRC. Inconsistent results or varying effect strengths could not be explained by different CIMP definitions used. No consistent variation in response to specific therapies according to CIMP status was found. Comparative analyses of different CIMP panels in the same large study populations are needed to further clarify the role of CIMP definitions and to find out how methylation information can best be used to predict CRC prognosis and response to specific CRC therapies.

  4. Dimorphous expressions of positive emotion: displays of both care and aggression in response to cute stimuli.

    Science.gov (United States)

    Aragón, Oriana R; Clark, Margaret S; Dyer, Rebecca L; Bargh, John A

    2015-03-01

    Extremely positive experiences, and positive appraisals thereof, produce intense positive emotions that often generate both positive expressions (e.g., smiles) and expressions normatively reserved for negative emotions (e.g., tears). We developed a definition of these dimorphous expressions and tested the proposal that their function is to regulate emotions. We showed that individuals who express emotions in this dimorphous manner do so as a general response across a variety of emotionally provoking situations, which suggests that these expressions are responses to intense positive emotion rather than unique to one particular situation. We used cute stimuli (an elicitor of positive emotion) to demonstrate both the existence of these dimorphous expressions and to provide preliminary evidence of their function as regulators of emotion. © The Author(s) 2015.

  5. A recursive Formulation of the Inversion of symmetric positive defite matrices in packed storage data format

    DEFF Research Database (Denmark)

    Andersen, Bjarne Stig; Gunnels, John A.; Gustavson, Fred

    2002-01-01

    A new Recursive Packed Inverse Calculation Algorithm for symmetric positive definite matrices has been developed. The new Recursive Inverse Calculation algorithm uses minimal storage, \\$n(n+1)/2\\$, and has nearly the same performance as the LAPACK full storage algorithm using \\$n\\^2\\$ memory words...

  6. A matter of definition--key elements identified in a discourse analysis of definitions of palliative care.

    Science.gov (United States)

    Pastrana, T; Jünger, S; Ostgathe, C; Elsner, F; Radbruch, L

    2008-04-01

    For more than 30 years, the term "palliative care" has been used. From the outset, the term has undergone a series of transformations in its definitions and consequently in its tasks and goals. There remains a lack of consensus on a definition. The aim of this article is to analyse the definitions of palliative care in the specialist literature and to identify the key elements of palliative care using discourse analysis: a qualitative methodology. The literature search focused on definitions of the term 'palliative medicine' and 'palliative care' in the World Wide Web and medical reference books in English and German. A total of 37 English and 26 German definitions were identified and analysed. Our study confirmed the lack of a consistent meaning concerning the investigated terms, reflecting on-going discussion about the nature of the field among palliative care practitioners. Several common key elements were identified. Four main categories emerged from the discourse analysis of the definition of palliative care: target groups, structure, tasks and expertise. In addition, the theoretical principles and goals of palliative care were discussed and found to be key elements, with relief and prevention of suffering and improvement of quality of life as main goals. The identified key elements can contribute to the definition of the concept 'palliative care'. Our study confirms the importance of semantic and ethical influences on palliative care that should be considered in future research on semantics in different languages.

  7. What is mental health? Evidence towards a new definition from a mixed methods multidisciplinary international survey

    Science.gov (United States)

    Manwell, Laurie A; Barbic, Skye P; Roberts, Karen; Durisko, Zachary; Lee, Cheolsoon; Ware, Emma; McKenzie, Kwame

    2015-01-01

    Objective Lack of consensus on the definition of mental health has implications for research, policy and practice. This study aims to start an international, interdisciplinary and inclusive dialogue to answer the question: What are the core concepts of mental health? Design and participants 50 people with expertise in the field of mental health from 8 countries completed an online survey. They identified the extent to which 4 current definitions were adequate and what the core concepts of mental health were. A qualitative thematic analysis was conducted of their responses. The results were validated at a consensus meeting of 58 clinicians, researchers and people with lived experience. Results 46% of respondents rated the Public Health Agency of Canada (PHAC, 2006) definition as the most preferred, 30% stated that none of the 4 definitions were satisfactory and only 20% said the WHO (2001) definition was their preferred choice. The least preferred definition of mental health was the general definition of health adapted from Huber et al (2011). The core concepts of mental health were highly varied and reflected different processes people used to answer the question. These processes included the overarching perspective or point of reference of respondents (positionality), the frameworks used to describe the core concepts (paradigms, theories and models), and the way social and environmental factors were considered to act. The core concepts of mental health identified were mainly individual and functional, in that they related to the ability or capacity of a person to effectively deal with or change his/her environment. A preliminary model for the processes used to conceptualise mental health is presented. Conclusions Answers to the question, ‘What are the core concepts of mental health?’ are highly dependent on the empirical frame used. Understanding these empirical frames is key to developing a useful consensus definition for diverse populations. PMID:26038353

  8. Numerical Simulation and Mechanical Design for TPS Electron Beam Position Monitors

    Science.gov (United States)

    Hsueh, H. P.; Kuan, C. K.; Ueng, T. S.; Hsiung, G. Y.; Chen, J. R.

    2007-01-01

    Comprehensive study on the mechanical design and numerical simulation for the high resolution electron beam position monitors are key steps to build the newly proposed 3rd generation synchrotron radiation research facility, Taiwan Photon Source (TPS). With more advanced electromagnetic simulation tool like MAFIA tailored specifically for particle accelerator, the design for the high resolution electron beam position monitors can be tested in such environment before they are experimentally tested. The design goal of our high resolution electron beam position monitors is to get the best resolution through sensitivity and signal optimization. The definitions and differences between resolution and sensitivity of electron beam position monitors will be explained. The design consideration is also explained. Prototype deign has been carried out and the related simulations were also carried out with MAFIA. The results are presented here. Sensitivity as high as 200 in x direction has been achieved in x direction at 500 MHz.

  9. Numerical Simulation and Mechanical Design for TPS Electron Beam Position Monitors

    International Nuclear Information System (INIS)

    Hsueh, H. P.; Kuan, C. K.; Ueng, T. S.; Hsiung, G. Y.; Chen, J. R.

    2007-01-01

    Comprehensive study on the mechanical design and numerical simulation for the high resolution electron beam position monitors are key steps to build the newly proposed 3rd generation synchrotron radiation research facility, Taiwan Photon Source (TPS). With more advanced electromagnetic simulation tool like MAFIA tailored specifically for particle accelerator, the design for the high resolution electron beam position monitors can be tested in such environment before they are experimentally tested. The design goal of our high resolution electron beam position monitors is to get the best resolution through sensitivity and signal optimization. The definitions and differences between resolution and sensitivity of electron beam position monitors will be explained. The design consideration is also explained. Prototype deign has been carried out and the related simulations were also carried out with MAFIA. The results are presented here. Sensitivity as high as 200 in x direction has been achieved in x direction at 500 MHz

  10. Matrix models with non-even potentials

    International Nuclear Information System (INIS)

    Marzban, C.; Raju Viswanathan, R.

    1990-07-01

    We study examples of hermitian 1-matrix models with even and odd terms present in the potential. A definition of criticality is presented which in these cases leads to multicritical models falling into the same universality classes as those of the purely even potentials. We also show that, in our examples, for polynomial potentials ending in odd powers (unbounded) the coupling constants, in addition to their expected real critical values, also admit critical values which alternate between imaginary/real values in the odd/even terms. We find that, remarkably, the ensuing statistical models are insensitive to the real/imaginary nature of these critical values. This feature may be of relevance in the recently-studied connection between matrix models and the moduli space of Riemann surfaces. (author). 9 refs

  11. A non-orthogonal decomposition of flows into discrete events

    Science.gov (United States)

    Boxx, Isaac; Lewalle, Jacques

    1998-11-01

    This work is based on the formula for the inverse Hermitian wavelet transform. A signal can be interpreted as a (non-unique) superposition of near-singular, partially overlapping events arising from Dirac functions and/or its derivatives combined with diffusion.( No dynamics implied: dimensionless diffusion is related to the definition of the analyzing wavelets.) These events correspond to local maxima of spectral energy density. We successfully fitted model events of various orders on a succession of fields, ranging from elementary signals to one-dimensional hot-wire traces. We document edge effects, event overlap and its implications on the algorithm. The interpretation of the discrete singularities as flow events (such as coherent structures) and the fundamental non-uniqueness of the decomposition are discussed. The dynamics of these events will be examined in the companion paper.

  12. 21 CFR 136.3 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... CONSUMPTION BAKERY PRODUCTS General Provisions § 136.3 Definitions. For purposes of this part, the following definitions apply: (a) The word bread when used in the name of the food means the unit weighs one-half pound...

  13. Pediatric acute respiratory distress syndrome: definition, incidence, and epidemiology: proceedings from the Pediatric Acute Lung Injury Consensus Conference.

    Science.gov (United States)

    Khemani, Robinder G; Smith, Lincoln S; Zimmerman, Jerry J; Erickson, Simon

    2015-06-01

    Although there are similarities in the pathophysiology of acute respiratory distress syndrome in adults and children, pediatric-specific practice patterns, comorbidities, and differences in outcome necessitate a pediatric-specific definition. We sought to create such a definition. A subgroup of pediatric acute respiratory distress syndrome investigators who drafted a pediatric-specific definition of acute respiratory distress syndrome based on consensus opinion and supported by detailed literature review tested elements of the definition with patient data from previously published investigations. International PICUs. Children enrolled in published investigations of pediatric acute respiratory distress syndrome. None. Several aspects of the proposed pediatric acute respiratory distress syndrome definition align with the Berlin Definition of acute respiratory distress syndrome in adults: timing of acute respiratory distress syndrome after a known risk factor, the potential for acute respiratory distress syndrome to coexist with left ventricular dysfunction, and the importance of identifying a group of patients at risk to develop acute respiratory distress syndrome. There are insufficient data to support any specific age for "adult" acute respiratory distress syndrome compared with "pediatric" acute respiratory distress syndrome. However, children with perinatal-related respiratory failure should be excluded from the definition of pediatric acute respiratory distress syndrome. Larger departures from the Berlin Definition surround 1) simplification of chest imaging criteria to eliminate bilateral infiltrates; 2) use of pulse oximetry-based criteria when PaO2 is unavailable; 3) inclusion of oxygenation index and oxygen saturation index instead of PaO2/FIO2 ratio with a minimum positive end-expiratory pressure level for invasively ventilated patients; 4) and specific inclusion of children with preexisting chronic lung disease or cyanotic congenital heart disease. This

  14. 10 CFR 830.3 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... structures, systems, and components; (3) Safety management programs; (4) Technical safety requirements; and..., construction, fabrication, assembly, decontamination, environmental restoration, waste management, laboratory... ENERGY NUCLEAR SAFETY MANAGEMENT § 830.3 Definitions. (a) The following definitions apply to this part...

  15. Categorizing Mistaken False Positives in Regulation of Human and Environmental Health

    DEFF Research Database (Denmark)

    Hansen, Steffen Foss; Krayer von Krauss, Martin Paul; Tickner, J.A.

    2007-01-01

    One of the concerns often voiced by critics of the precautionary principle is that a widespread regulatory application of the principle will lead to a large number of false positives (i.e., over-regulation of minor risks and regulation of nonexisting risks). The present article proposes a general......," including: real risks, "The jury is still out," nonregulated proclaimed risks, "Too narrow a definition of risk," and risk-risk tradeoffs. These categories are defined and examples are presented in order to illustrate their key characteristics. On the basis of our analysis, we were able to identify only...... four cases that could be defined as regulatory false positives in the light of today's knowledge and recognized uncertainty: the Southern Corn Leaf Blight, the Swine Flu, Saccharin, and Food Irradiation in relation to consumer health. We conclude that concerns about false positives do not represent...

  16. A note on antennas: Definitions and methods

    DEFF Research Database (Denmark)

    Bach, Henning

    1987-01-01

    Definitions of scattered and diffracted fields, originally given by R. F. Millar, are reviewed and supplemented. The definitions are used to discuss relations between results obtained by commonly used pattern prediction methods for reflector antennas.......Definitions of scattered and diffracted fields, originally given by R. F. Millar, are reviewed and supplemented. The definitions are used to discuss relations between results obtained by commonly used pattern prediction methods for reflector antennas....

  17. New definition of the cell diffusion coefficient

    International Nuclear Information System (INIS)

    Koehler, P.

    1975-01-01

    As was shown in a recent work by Gelbard, the usually applied Benoist definition of the cell diffusion coefficient gives two different values if two different definitions of the cell are made. A new definition is proposed that preserves the neutron balance for the homogenized lattice and that is independent of the cell definition. The resulting diffusion coefficient is identical with the main term of Benoist's diffusion coefficient

  18. Accuracy of clinical diagnosis versus the World Health Organization case definition in the Amoy Garden SARS cohort.

    Science.gov (United States)

    Wong, W N; Sek, Antonio C H; Lau, Rick F L; Li, K M; Leung, Joe K S; Tse, M L; Ng, Andy H W; Stenstrom, Robert

    2003-11-01

    To compare the diagnostic accuracy of emergency department (ED) physicians with the World Health Organization (WHO) case definition in a large community-based SARS (severe acute respiratory syndrome) cohort. This was a cohort study of all patients from Hong Kong's Amoy Garden complex who presented to an ED SARS screening clinic during a 2-month outbreak. Clinical findings and WHO case definition criteria were recorded, along with ED diagnoses. Final diagnoses were established independently based on relevant diagnostic tests performed after the ED visit. Emergency physician diagnostic accuracy was compared with that of the WHO SARS case definition. Sensitivity, specificity, predictive values and likelihood ratios were calculated using standard formulae. During the study period, 818 patients presented with SARS-like symptoms, including 205 confirmed SARS, 35 undetermined SARS and 578 non-SARS. Sensitivity, specificity and accuracy were 91%, 96% and 94% for ED clinical diagnosis, versus 42%, 86% and 75% for the WHO case definition. Positive likelihood ratios (LR+) were 21.1 for physician judgement and 3.1 for the WHO criteria. Negative likelihood ratios (LR-) were 0.10 for physician judgement and 0.67 for the WHO criteria, indicating that clinician judgement was a much more powerful predictor than the WHO criteria. Physician clinical judgement was more accurate than the WHO case definition. Reliance on the WHO case definition as a SARS screening tool may lead to an unacceptable rate of misdiagnosis. The SARS case definition must be revised if it is to be used as a screening tool in emergency departments and primary care settings.

  19. 50 CFR 453.02 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS ENDANGERED SPECIES EXEMPTION PROCESS ENDANGERED SPECIES COMMITTEE § 453.02 Definitions. Definitions applicable to this part are contained in 50... Wildlife and Fisheries JOINT REGULATIONS (UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE...

  20. 16 CFR 1031.10 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION GENERAL COMMISSION PARTICIPATION AND COMMISSION EMPLOYEE INVOLVEMENT IN VOLUNTARY STANDARDS ACTIVITIES Employee Involvement § 1031.10 Definitions. For... employees may be authorized, the following definitions apply: (a) Membership. Membership is the status of an...