Configuration space Faddeev calculations

International Nuclear Information System (INIS)

Payne, G.L.; Klink, W.H.; Ployzou, W.N.

1991-01-01

The detailed study of few-body systems provides one of the most precise tools for studying the dynamics of nuclei. Our research program consists of a careful theoretical study of the nuclear few-body systems. During the past year we have completed several aspects of this program. We have continued our program of using the trinucleon system to investigate the validity of various realistic nucleon-nucleon potentials. Also, the effects of meson-exchange currents in nuclear systems have been studied. Initial calculations using the configuration-space Faddeev equations for nucleon-deuteron scattering have been completed. With modifications to treat relativistic systems, few-body methods can be applied to phenomena that are sensitive to the structure of the individual hadrons. We have completed a review of Relativistic Hamiltonian Dynamics in Nuclear and Particle Physics for Advances in Nuclear Physics. Although it is called a review, it is a large document that contains a significant amount of new research

Faddeev-Yakubovsky calculations for light Lambda-Lambda hypernuclei

OpenAIRE

Filikhin, I. N.; Gal, A.

2002-01-01

New Faddeev-Yakubovsky calculations are reported for Lambda-Lambda-6He and Lambda-Lambda-10Be in terms of clusters of alpha's and Lambda's, using Lambda-Lambda s-wave potentials motivated by several of the Nijmegen model interactions. The self consistency of the Lambda-Lambda hypernuclear world data for these species is discussed. The newly reported Lambda-Lambda-6He event is found to be compatible with Lambda-Lambda interaction strengths provided by the Nijmegen soft-core one-boson-exchange ...

Cabling in the Skyrme–Faddeev model

International Nuclear Information System (INIS)

Jennings, Paul

2015-01-01

The Skyrme–Faddeev model is a three-dimensional nonlinear field theory that has topological soliton solutions, called hopfions, which are novel string-like solutions taking the form of knots and links. Solutions found thus far take the form of torus knots and links of these, however torus knots form only a small family of known knots. It is an open question whether any non-torus knot hopfions exist. In this paper we present a construction of knotted fields with the form of cable knots to which an energy minimization scheme can be applied. We find the first known hopfions which do not have the form of torus knots, but instead take the form of cable and hyperbolic knots. (paper)

From Faddeev-Kulish to LSZ. Towards a non-perturbative description of colliding electrons

Science.gov (United States)

Dybalski, Wojciech

2017-12-01

In a low energy approximation of the massless Yukawa theory (Nelson model) we derive a Faddeev-Kulish type formula for the scattering matrix of N electrons and reformulate it in LSZ terms. To this end, we perform a decomposition of the infrared finite Dollard modifier into clouds of real and virtual photons, whose infrared divergencies mutually cancel. We point out that in the original work of Faddeev and Kulish the clouds of real photons are omitted, and consequently their wave-operators are ill-defined on the Fock space of free electrons. To support our observations, we compare our final LSZ expression for N = 1 with a rigorous non-perturbative construction due to Pizzo. While our discussion contains some heuristic steps, they can be formulated as clear-cut mathematical conjectures.

QCD gauge symmetries through Faddeev-Jackiw symplectic method

International Nuclear Information System (INIS)

Abreu, E.M.C.; Mendes, A.C.R.; Neves, C.; Oliveira, W.; Silva, R.C.N.

2013-01-01

Full text: The FJ method is an approach that is geometrically motivated. It is based on the symplectic structure of the phase space. The first-order characteristic allows to obtain the Hamiltonian equations of motion from a variational principle. Its geometric structure of the Hamiltonian phase-space will be carried out directly from the equations of motion via the inverse of the so-called symplectic two-form, if the inverse exists. Few years after its publication, the FJ formalism was extended and through the years it has been applied to different systems. Gauge invariance is one of the most well established concepts in theoretical physics and it is one of the main ingredients in Standard Model theory. However, we can ask if it could have an alternative origin connected to another theory or principle. With this motivation in mind we will show in this paper that gauge invariance could be considered an emergent concept having its origin in the algebraic formalism of a well known method that deals with constrained systems, namely, the Faddeev-Jackiw (FJ) technique. Of course the gauge invariance idea is older than FJ's, but the results obtained here will show that the connection between both will prove that SU(3) and SU(3) X SU(2) X U(1) gauge groups, which are fundamental to important theories like QCD and Standard Model, can be obtained through FJ formalism. (author)

The Faddeev equation and essential spectrum of a Hamiltonian in Fock space

International Nuclear Information System (INIS)

Muminov, M.I.; Rasulov, T.H.

2008-05-01

A model operator H associated to a quantum system with non conserved number of particles is studied. The Faddeev type system of equation for eigenvectors of H is constructed. The essential spectrum of H is described by the spectrum of the channel operator. (author)

Constrained dynamics of two interacting relativistic particles in the Faddeev-Jackiw symplectic framework

Science.gov (United States)

Rodríguez-Tzompantzi, Omar

2018-05-01

The Faddeev-Jackiw symplectic formalism for constrained systems is applied to analyze the dynamical content of a model describing two massive relativistic particles with interaction, which can also be interpreted as a bigravity model in one dimension. We systematically investigate the nature of the physical constraints, for which we also determine the zero-modes structure of the corresponding symplectic matrix. After identifying the whole set of constraints, we find out the transformation laws for all the set of dynamical variables corresponding to gauge symmetries, encoded in the remaining zero modes. In addition, we use an appropriate gauge-fixing procedure, the conformal gauge, to compute the quantization brackets (Faddeev-Jackiw brackets) and also obtain the number of physical degree of freedom. Finally, we argue that this symplectic approach can be helpful for assessing physical constraints and understanding the gauge structure of theories of interacting spin-2 fields.

Nucleon Mass from a Covariant Three-Quark Faddeev Equation

International Nuclear Information System (INIS)

Eichmann, G.; Alkofer, R.; Krassnigg, A.; Nicmorus, D.

2010-01-01

We report the first study of the nucleon where the full Poincare-covariant structure of the three-quark amplitude is implemented in the Faddeev equation. We employ an interaction kernel which is consistent with contemporary studies of meson properties and aspects of chiral symmetry and its dynamical breaking, thus yielding a comprehensive approach to hadron physics. The resulting current-mass evolution of the nucleon mass compares well with lattice data and deviates only by ∼5% from the quark-diquark result obtained in previous studies.

Reduction of static field equation of Faddeev model to first order PDE

International Nuclear Information System (INIS)

Hirayama, Minoru; Shi Changguang

2007-01-01

A method to solve the static field equation of the Faddeev model is presented. For a special combination of the concerned field, we adopt a form which is compatible with the field equation and involves two arbitrary complex functions. As a result, the static field equation is reduced to a set of first order partial differential equations

Some applications of the Faddeev-Yakubovsky equations to the cold-atom physics

International Nuclear Information System (INIS)

Carbonell, J.; Deltuva, A.; Lazauskas, R.

2011-01-01

We present some recent applications of the Faddeev-Yakubovsky equations in describing atomic bound and scattering problems. We consider the scattering of a charged particle X by atomic hydrogen with special interest in X = p,e ± , systems of cold bosonic molecules and the bound and scattering properties of N=3 and N=4 atomic 4 He multimers. (authors)

Faddeev calculations for the A=5,6 Lambda-Lambda hypernuclei

OpenAIRE

Filikhin, I. N.; Gal, A.; Suslov, V. M.

2003-01-01

Faddev calculations are reported for Lambda-Lambda-5H, Lambda-Lambda-5He and Lambda-Lambda-6He in terms of two Lambda hyperons plus the respective nuclear clusters, using Lambda-Lambda central potentials considered in past non-Faddeev calculations of Lambda-Lambda-6He. The convergence with respect to the partial-wave expansion is studied, and comparison is made with some of these Lambda-Lambda hypernuclear calculations. The Lambda-Lambda Xi-N mixing effect is briefly discussed.

3H and 3He nucleus structure by Faddeev equations in the configuration space

International Nuclear Information System (INIS)

Laverne, A.

1973-06-01

To solve the triton problem, Faddeev equations are solved in configuration space. The method is described (algorithm) together with some results with nucleon-nucleon potentials such as Reid potential and Tourreil and Sprung potential. A comparative study with helium 3 is given [fr

Comparison of numerical approaches to solve a Poincare-covariant Faddeev equation

International Nuclear Information System (INIS)

Alkofer, R.; Eichmann, G.; Krassnigg, A.; Schwinzerl, M.

2006-01-01

Full text: The quark core of Baryons can be described with the help of the numerical solution of the Poincare-Faddeev equation. Hereby the used elements, as e.g. the quark propagator are taken from non-perturbative studies of Landau gauge QCD. Different numerical approaches to solve in this way the relativistic three quark problem are compared and benchmarked results for the efficiency of different algorithms are presented. (author)

The tree-alpha Faddeev calculation on 12C bound states with a Pauli correct alpha-alpha potential

International Nuclear Information System (INIS)

Kamada, Hiroyuki; Oryu, Shinsho

1986-01-01

The three-alpha model of 12 C is investigated by the Faddeev formalism with the UIM alpha-alpha potential, in which the Pauli effect between two-alpha system was taken into account adequately. The potential can reproduce the on- and off-shell effects of the alpha-alpha interaction by the rank-4 separable type for the S-wave, the rank-3 one for the D-wave, and the rank-2 one for the G-wave, in which two of the ranks in the S-wave, and one in the D-wave are prepared to eliminate the Pauli forbidden states. We obtained three even states J π = 0 + , 2 + , 4 + , and two odd states 1 - , 3 - , below the alpha- 8 Be(0 + g.s) threshold energy. The even parity states gain larger binding energies than those which have been obtained by former Faddeev calculation with the rank-1 Kukulin and Neudatchin (KN) potential. On the other hand, for the odd parity states, we obtained smaller binding energies than the former one. It is found that our Faddeev calculation with the UIM potential does not miss any important low-lying levels of 12 C, in which any spurious states do not appear. (author)

Quasi-four-particle first-order Faddeev-Watson-Lovelace terms in proton-helium scattering

Science.gov (United States)

Safarzade, Zohre; Akbarabadi, Farideh Shojaei; Fathi, Reza; Brunger, Michael J.; Bolorizadeh, Mohammad A.

2017-06-01

The Faddeev-Watson-Lovelace equations, which are typically used for solving three-particle scattering problems, are based on the assumption of target having one active electron while the other electrons remain passive during the collision process. So, in the case of protons scattering from helium or helium-like targets, in which there are two bound-state electrons, the passive electron has a static role in the collision channel to be studied. In this work, we intend to assign a dynamic role to all the target electrons, as they are physically active in the collision. By including an active role for the second electron in proton-helium-like collisions, a new form of the Faddeev-Watson-Lovelace integral equations is needed, in which there is no disconnected kernel. We consider the operators and the wave functions associated with the electrons to obey the Pauli exclusion principle, as the electrons are indistinguishable. In addition, a quasi-three-particle collision is assumed in the initial channel, where the electronic cloud is represented as a single identity in the collision.

Fully-converged three-dimensional collision-induced dissociation calculations with Faddeev-AGS theory

International Nuclear Information System (INIS)

Haftel, M.I.; Lim, T.K.

1981-09-01

The first fully-converged quantum-mechanical calculation of the collision-induced dissociation cross section in a three-dimensional-model system of three helium-like atoms is reported. Faddeev-AGS theory is used. It yields as a bonus the elastic atom-diatom cross section. The obtained results resemble those from some collinear models but indicate clearly the futility of multiple-scattering approximations except at hyperthermal energies. (orig.)

FADDEEV: A fortran code for the calculation of the frequency response matrix of multiple-input, multiple-output dynamic systems

International Nuclear Information System (INIS)

Owens, D.H.

1972-06-01

The KDF9/EGDON programme FADDEEV has been written to investigate a technique for the calculation of the matrix of frequency responses G(jw) describing the response of the output vector y from the multivariable differential/algebraic system S to the drive of the system input vector u. S: Ex = Ax + Bu, y = Cx, G(jw) = C(jw E - A ) -1 B. The programme uses an algorithm due to Faddeev and has been written with emphasis upon: (a) simplicity of programme structure and computational technique which should enable a user to find his way through the programme fairly easily, and hence facilitate its manipulation as a subroutine in a larger code; (b) rapid computational ability, particularly in systems with fairly large number of inputs and outputs and requiring the evaluation of the frequency responses at a large number of frequencies. Transport or time delays must be converted by the user to Pade or Bode approximations prior to input. Conditions under which the algorithm fails to give accurate results are identified, and methods for increasing the accuracy of the calculations are discussed. The conditions for accurate results using FADDEEV indicate that its application is specialized. (author)

Relativistic Faddeev description of baryons and nucleon structure function in the NJL model

Energy Technology Data Exchange (ETDEWEB)

Bentz, W.; Mineo, H.; Asami, H.; Yazaki, K

2000-05-08

In this work we use the Nambu-Jona-Lasinio (NJL) model as an effective quark theory based on QCD to describe the structure of baryons. Based on the solutions of the relativistic 3-quark Faddeev equation in the ladder approximation, we discuss the masses of the nucleon and the delta, the static properties of the nucleon, and the quark light cone momentum distributions in the nucleon.

Faddeev equations with an extra resonance channel in muon catalysis

International Nuclear Information System (INIS)

Motovilov, A.K.; Kuperin, Yu.A.; Susko, A.A.; Vinitskij, S.I.

1988-01-01

A three-body model is applied to derive inhomogeneous integral and differential Faddeev equations with energy-dependent potentials. The integral equations are shown to be Fredholm equations. The stricking probability ω s is determined in terms of the amplitudes of spherical waves in the asymptotics of the exit-channel wave function. The integral representation for ω s is given in terms of the continuum wave functions. To the first Born Approximation for the wave function, this representation yields an explicit expression for ω s through the expansion coefficients of the wave function of dtμ of the initial channel

FaCE: a tool for Three Body Faddeev calculations with core excitation

OpenAIRE

Thompson, I. J.; Nunes, F. M.; Danilin, B. V.

2004-01-01

FaCE is a self contained programme, with namelist input, that solves the three body Faddeev equations. It enables the inclusion of excitation of one of the three bodies, whilst the other two remain inert. It is particularly useful for obtaining the binding energies and bound state structure compositions of light exotic nuclei treated as three-body systems, given the three effective two body interactions. A large variety of forms for these interactions may be defined, and supersymmetric transf...

Scientific heritage of L.D. Faddeev. Survey of papers

Science.gov (United States)

Takhtajan, L. A.; Alekseev, A. Yu; Aref'eva, I. Ya; Semenov-Tian-Shansky, M. A.; Sklyanin, E. K.; Smirnov, F. A.; Shatashvili, S. L.

2017-12-01

This survey was written by students of L.D. Faddeev under the editorship of L.A. Takhtajan. Sections 1.1, 1.2, 2-4, and 6 were written by Takhtajan, §§1.3 and 1.4 by F.A. Smirnov, §§5.1 and 5.2 by E.K. Sklyanin, §§5.3-5.6 by Sklyanin, Smirnov, and Takhtajan, §7.1 by M.A. Semenov-Tian-Shansky, §§7.2-7.6 by Takhtajan and S.L. Shatashvili, §7.7 by A.Yu. Alekseev and Shatashvili, and §8 by I.Ya. Aref'eva. Bibliography: 130 titles.

Faddeev-Jackiw Hamiltonian reduction for free and gauged Rarita-Schwinger theories

Energy Technology Data Exchange (ETDEWEB)

Dengiz, Suat [Massachusetts Institute of Technology, Center for Theoretical Physics, Cambridge, MA (United States)

2016-10-15

We study the Faddeev-Jackiw symplectic Hamiltonian reduction for 3 + 1-dimensional free and Abelian gauged Rarita-Schwinger theories that comprise Grassmannian fermionic fields. We obtain the relevant fundamental brackets and find that they are in convenient forms for quantization. The brackets are independent of whether the theories contain mass or gauge fields, and the structures of constraints and symplectic potentials largely determine characteristic behaviors of the theories. We also note that, in contrast to the free massive theory, the Dirac field equations for free massless Rarita-Schwinger theory cannot be obtained in a covariant way. (orig.)

Comparative analysis of approximations used in the methods of Faddeev equations and hyperspherical harmonics

International Nuclear Information System (INIS)

Mukhtarova, M.I.

1988-01-01

Comparative analysis of approximations, used in the methods of Faddeev equations and hyperspherical harmonics (MHH) was conducted. The differences in solutions of these methods, related with introduction of approximation of sufficient partial states into the three-nucleon problem, is shown. MHH method is preferred. It is shown that MHH advantage can be manifested clearly when studying new classes of interactions: three-particle, Δ-isobar, nonlocal and other interactions

Micro-Texture Synthesis by Phase Randomization

Directory of Open Access Journals (Sweden)

Bruno Galerne

2011-09-01

Full Text Available This contribution is concerned with texture synthesis by example, the process of generating new texture images from a given sample. The Random Phase Noise algorithm presented here synthesizes a texture from an original image by simply randomizing its Fourier phase. It is able to reproduce textures which are characterized by their Fourier modulus, namely the random phase textures (or micro-textures.

Dynamical effects in non-relativistic description of N-N interaction using Faddeev solution for 3-q nucleon

International Nuclear Information System (INIS)

Silvestre-Brac, B.; Jain, A.K.; Gignoux, C.

1983-11-01

A formalism has been developed to treat the two nucleon behaviour with the incorporation of 3-quark dynamics from Faddeev equations. This formalism in which six quark hamiltonian is decomposed in terms of nucleons internal hamiltonians and internucleon q-q interaction permits us to treat the nucleon internal dynamics properly. The short distance N-N behaviour has been described very well

A new perspective on the Faddeev equations and the K{sup Macron}NN system from chiral dynamics and unitarity in coupled channels

Energy Technology Data Exchange (ETDEWEB)

Oset, E. [Instituto de Fisica Corpuscular (centro mixto CSIC-UV), Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Jido, D. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Sekihara, T. [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Martinez Torres, A. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Khemchandani, K.P. [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Bayar, M., E-mail: melahat@ific.uv.es [Instituto de Fisica Corpuscular (centro mixto CSIC-UV), Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Department of Physics, Kocaeli University, 41380 Izmit (Turkey); Yamagata-Sekihara, J. [Instituto de Fisica Corpuscular (centro mixto CSIC-UV), Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

2012-05-01

We review recent work concerning the K{sup Macron}N interaction and Faddeev equations with chiral dynamics which allow us to look at the K{sup Macron}NN from a different perspective and pay attention to problems that have been posed in previous studies on the subject. We then show results which provide extra experimental evidence on the existence of two {Lambda}(1405) states. Then show the findings of a recent approach to Faddeev equations using chiral unitary dynamics, where an explicit cancellation of the two-body off-shell amplitude with three-body forces stemming from the same chiral Lagrangians takes place. This removal of the unphysical off-shell part of the amplitudes is most welcome and renders the approach unambiguous, showing that only on-shell two-body amplitudes need to be used. With this information in mind we use an approximation to the Faddeev equations within the fixed center approximation to study the K{sup Macron}NN system, providing answers within this approximation to questions that have been brought before and evaluating binding energies and widths of this three-body system. As a novelty with respect to recent work on the topic we find a bound state of the system with spin S=1, like a bound state of K{sup Macron}-deuteron, less bound that the one of S=0, where all recent efforts have been devoted. The width is relatively large in this case, suggesting problems in a possible experimental observation.

Coulomb-Sturmian separable expansion approach: Three-body Faddeev calculations for Coulomb-like interactions

International Nuclear Information System (INIS)

Papp, Z.; Plessas, W.

1996-01-01

We demonstrate the feasibility and efficiency of the Coulomb-Sturmian separable expansion method for generating accurate solutions of the Faddeev equations. Results obtained with this method are reported for several benchmark cases of bosonic and fermionic three-body systems. Correct bound-state results in agreement with the ones established in the literature are achieved for short-range interactions. We outline the formalism for the treatment of three-body Coulomb systems and present a bound-state calculation for a three-boson system interacting via Coulomb plus short-range forces. The corresponding result is in good agreement with the answer from a recent stochastic-variational-method calculation. copyright 1996 The American Physical Society

3He(d,p)4He reaction calculation with three-body Faddeev equations

International Nuclear Information System (INIS)

Oryu, S.; Uzu, E.; Sunahara, H.; Yamada, T.; Tabaru, G.; Hino, T.

1998-01-01

In order to investigate the 3 He-n-p system as a three-body problem, we have formulated 3 He-n and 3 H-p effective potentials using both a microscopic treatment and a phenomenological approach. In the microscopic treatment, potentials are generated by means of the resonating group method (RGM) based on the Minnesota nucleon-nucleon potential. These potentials are converted into separable form by means of the microscopic Pauli correct (MPC) method. The MPC potentials are properly formulated to avoid Pauli forbidden states. The phenomenological potentials are obtained by modifying parameters of the EST approximation to the Paris nucleon-nucleon potential, such that they fit the low-energy 3 He-n, 3 H-p, and 3 He-p phase shifts. Therefore, they describe the 3 He-n differential cross section, the polarization observables, and the energy levels of 4 He. The 3 He-n-p Faddeev equations are solved numerically. We reproduce correctly the ground state and the first excited state of 5 Li. Furthermore, the Paris-type potential is used to investigate the 3 He(d,p) 4 He reaction at a deuteron bombarding energy of 270 MeV, where the system is treated as a three-body problem. Results for the polarized and unpolarized differential cross sections demonstrate convergence of the Born series. (orig.)

Faddeev-Senjanovic quantization of SU(n) N=2 supersymmetric gauge field system with a non-Abelian Chern-Simons topological term and its fractional spin

International Nuclear Information System (INIS)

Huang Yongchang; Huo Qiuhong

2008-01-01

Using Faddeev-Senjanovic path integral quantization for constrained Hamilton system, we quantize SU(n) N=2 supersymmetric gauge field system with non-Abelian Chern-Simons topological term in 2+1 dimensions. We use consistency of Coulomb gauge condition to naturally deduce a new gauge condition. Furthermore, we obtain the generating functional of Green function in phase space, deduce the angular momentum based on the global canonical Noether theorem at quantum level, obtain the fractional spin of this supersymmetric system, and show that the total angular momentum is the sum of the orbital angular momentum and spin angular momentum of the non-Abelian gauge field. Finally, we obtain the anomalous fractional spin and discover that the fractional spin has the contributions of both the group superscript components and A 0 s (x) charge

Review of Random Phase Encoding in Volume Holographic Storage

Directory of Open Access Journals (Sweden)

Wei-Chia Su

2012-09-01

Full Text Available Random phase encoding is a unique technique for volume hologram which can be applied to various applications such as holographic multiplexing storage, image encryption, and optical sensing. In this review article, we first review and discuss diffraction selectivity of random phase encoding in volume holograms, which is the most important parameter related to multiplexing capacity of volume holographic storage. We then review an image encryption system based on random phase encoding. The alignment of phase key for decryption of the encoded image stored in holographic memory is analyzed and discussed. In the latter part of the review, an all-optical sensing system implemented by random phase encoding and holographic interconnection is presented.

Statistics of light deflection in a random two-phase medium

International Nuclear Information System (INIS)

Sviridov, A P

2007-01-01

The statistics of the angles of light deflection during its propagation in a random two-phase medium with randomly oriented phase interfaces is considered within the framework of geometrical optics. The probabilities of finding a randomly walking photon in different phases of the inhomogeneous medium are calculated. Analytic expressions are obtained for the scattering phase function and the scattering phase matrix which relates the Stokes vector of the incident light beam with the Stokes vectors of deflected beams. (special issue devoted to multiple radiation scattering in random media)

Random matrix models for phase diagrams

International Nuclear Information System (INIS)

Vanderheyden, B; Jackson, A D

2011-01-01

We describe a random matrix approach that can provide generic and readily soluble mean-field descriptions of the phase diagram for a variety of systems ranging from quantum chromodynamics to high-T c materials. Instead of working from specific models, phase diagrams are constructed by averaging over the ensemble of theories that possesses the relevant symmetries of the problem. Although approximate in nature, this approach has a number of advantages. First, it can be useful in distinguishing generic features from model-dependent details. Second, it can help in understanding the 'minimal' number of symmetry constraints required to reproduce specific phase structures. Third, the robustness of predictions can be checked with respect to variations in the detailed description of the interactions. Finally, near critical points, random matrix models bear strong similarities to Ginsburg-Landau theories with the advantage of additional constraints inherited from the symmetries of the underlying interaction. These constraints can be helpful in ruling out certain topologies in the phase diagram. In this Key Issues Review, we illustrate the basic structure of random matrix models, discuss their strengths and weaknesses, and consider the kinds of system to which they can be applied.

Trions in bulk and monolayer materials: Faddeev equations and hyperspherical harmonics.

Science.gov (United States)

Filikhin, I; Kezerashvili, R Ya; Tsiklauri, Sh M; Vlahovic, B

2018-03-23

The negatively T - and positively T + charged trions in bulk and monolayer semiconductors are studied in the effective mass approximation within the framework of a potential model. The binding energies of trions in various semiconductors are calculated by employing the Faddeev equation with the Coulomb potential in 3D configuration space. Results of calculations of the binding energies for T - are consistent with previous computational studies, while the T + is unbound for all considered cases. The binding energies of trions in monolayer semiconductors are calculated using the method of hyperspherical harmonics by employing the Keldysh potential. It is shown that 2D T - and T + trions are bound and the binding energy of the positive trion is always greater than for the negative trion due to the heavier effective mass of holes. Our calculations demonstrate that screening effects play an important role in the formation of bound states of trions in 2D semiconductors.

Enhanced wavefront reconstruction by random phase modulation with a phase diffuser

DEFF Research Database (Denmark)

Almoro, Percival F; Pedrini, Giancarlo; Gundu, Phanindra Narayan

2011-01-01

propagation in free space. The presentation of this technique is carried out using two setups. In the first setup, a diffuser plate is placed at the image plane of a metallic test object. The benefit of randomizing the phase of the object wave is the enhanced intensity recording due to high dynamic range...... of the diffusely scattered beam. The use of demagnification optics will also allow the investigations of relatively large objects. In the second setup, a transparent object is illuminated using a wavefront with random phase and constant amplitude by positioning the phase diffuser close to the object. The benefit...

On the calculation of the eigenvalues of the Faddeev equation kernel on the nonphysical sheet of energy

International Nuclear Information System (INIS)

Moeller, K.

1978-01-01

A system of three particles is considered which interacts by rank-1 separable potential. For the Faddeev equation kernel of this system a method is proposed for calculating the eigenvalues on the nonphysical sheet of the three-particle cms-energy. From the consideration of the analytical structure of the eigenvalues in the energy plane it follows that the analytical continuations of the eigenvalues from the physical to the nonphysical region are different above and below the three-particle threshold. In this paper the continuation below the threshold is discussed. (author)

Faddeev calculations of the (K)over-bar N N system with a chirally motivated (K)over-bar N interaction. II. The K- pp quasibound state

Czech Academy of Sciences Publication Activity Database

Revai, J.; Shevchenko, Nina V.

2014-01-01

Roč. 90, č. 3 (2014), 034004 ISSN 0556-2813 R&D Projects: GA ČR(CZ) GAP203/12/2126; GA MŠk LG14038 Institutional support: RVO:61389005 Keywords : Faddeev calculations * scattering Subject RIV: BE - Theoretical Physics Impact factor: 3.733, year: 2014

Analysis of 2H(d vector, p)3H reaction at 30-90 keV by four-body Faddeev-Yakubovsky equation

International Nuclear Information System (INIS)

Uzu, Eizo; Oryu, Shinsho; Tanifuji, Makoto.

1993-01-01

Low-energy 2 H(d vector, p) 3 H reactions are investigated by the four-body Faddeev-Yakubovsky equations. Cross sections and tensor analyzing powers are calculated at 30-90 keV energies. The PEST-1 potentials are used for nucleon-nucleon interactions. The [2+2] and [3+1] subamplitudes are treated by the Hilbert-Schmidt expansions. Numerical results give qualitative explanation of experimental data. (author)

Dynamical effects in the non-relativistic description of the N-N interaction using the Faddeev solution for the 3-q nucleon

International Nuclear Information System (INIS)

Silvestre-Brac, B.; Jain, A.K.; Gignoux, C.

1984-01-01

A formalism has been developed to treat the two nucleon behaviour with the incorporation of three-quark dynamics from Faddeev equations. This formalism in which a six-quark hamiltonian is decomposed in terms of nucleons, internal hamiltonians and the internucleon q-q interaction permits us to treat the nucleon internal dynamics properly. The short distance N-N behaviour has been described very well. (orig.)

Quantum phase transitions in random XY spin chains

International Nuclear Information System (INIS)

Bunder, J.E.; McKenzie, R.H.

2000-01-01

Full text: The XY spin chain in a transverse field is one of the simplest quantum spin models. It is a reasonable model for heavy fermion materials such as CeCu 6-x Au x . It has two quantum phase transitions: the Ising transition and the anisotropic transition. Quantum phase transitions occur at zero temperature. We are investigating what effect the introduction of randomness has on these quantum phase transitions. Disordered systems which undergo quantum phase transitions can exhibit new universality classes. The universality class of a phase transition is defined by the set of critical exponents. In a random system with quantum phase transitions we can observe Griffiths-McCoy singularities. Such singularities are observed in regions which have no long range order, so they are not classified as critical regions, yet they display phenomena normally associated with critical points, such as a diverging susceptibility. Griffiths-McCoy phases are due to rare regions with stronger than! average interactions and may be present far from the quantum critical point. We show how the random XY spin chain may be mapped onto a random Dirac equation. This allows us to calculate the density of states without making any approximations. From the density of states we can describe the conditions which should allow a Griffiths-McCoy phase. We find that for the Ising transition the dynamic critical exponent, z, is not universal. It is proportional to the disorder strength and inversely proportional to the energy gap, hence z becomes infinite at the critical point where the energy gap vanishes

Cryptographic analysis on the key space of optical phase encryption algorithm based on the design of discrete random phase mask

Science.gov (United States)

Lin, Chao; Shen, Xueju; Li, Zengyan

2013-07-01

The key space of phase encryption algorithm using discrete random phase mask is investigated by numerical simulation in this paper. Random phase mask with finite and discrete phase levels is considered as the core component in most practical optical encryption architectures. The key space analysis is based on the design criteria of discrete random phase mask. The role of random amplitude mask and random phase mask in optical encryption system is identified from the perspective of confusion and diffusion. The properties of discrete random phase mask in a practical double random phase encoding scheme working in both amplitude encoding (AE) and phase encoding (PE) modes are comparably analyzed. The key space of random phase encryption algorithm is evaluated considering both the encryption quality and the brute-force attack resistibility. A method for enlarging the key space of phase encryption algorithm is also proposed to enhance the security of optical phase encryption techniques.

Three Phase Power Imbalance Decomposition into Systematic Imbalance and Random Imbalance

DEFF Research Database (Denmark)

Kong, Wangwei; Ma, Kang; Wu, Qiuwei

2017-01-01

Uneven load allocations and random load behaviors are two major causes for three-phase power imbalance. The former mainly cause systematic imbalance, which can be addressed by low-cost phase swapping; the latter contribute to random imbalance, which requires relatively costly demand...... minimum phase, or both. Then, this paper proposes a new method to decompose three-phase power series into a systematic imbalance component and a random imbalance component as the closed-form solutions of quadratic optimization models that minimize random imbalance. A degree of power imbalance...... is calculated based on the systematic imbalance component to guide phase swapping. Case studies demonstrate that 72.8% of 782 low voltage substations have systematic imbalance components. The degree of power imbalance results reveal the maximum need for phase swapping and the random imbalance components reveal...

Phase behavior of random copolymers in quenched random media

International Nuclear Information System (INIS)

Chakraborty, A.K.; Shakhnovich, E.I.

1995-01-01

In this paper, we consider the behavior of random heteropolymers in a quenched disordered medium. We develop a field theory and obtain a mean-field solution that allows for replica symmetry breaking. The presence of an external disorder leads to the formation of compact states; a homopolymeric effect. We compute the phase diagram for two classes of problems. First, we consider the situation wherein the bare heteropolymer prefers like segments to segregate, and second, we examine cases where the bare heteropolymer prefers unlike segments to mix. For the first class of systems, we find a phase diagram characterized by a replica symmetry broken phase that exists below a particular temperature. This temperature grows with the strength of the external disorder. In the second class of situations, the phase diagram is much richer. Here we find two replica symmetry broken phases with different patterns separated by a reentrant phase. The reentrant phase and one of the two replica symmetry broken phases are induced by interactions with the external disorder. The dependence of the location of the phase boundaries on the strength of the external disorder are elucidated. We discuss our results from a physical standpoint, and note the testable experimental consequences of our findings. copyright 1995 American Institute of Physics

Number-conserving random phase approximation with analytically integrated matrix elements

International Nuclear Information System (INIS)

Kyotoku, M.; Schmid, K.W.; Gruemmer, F.; Faessler, A.

1990-01-01

In the present paper a number conserving random phase approximation is derived as a special case of the recently developed random phase approximation in general symmetry projected quasiparticle mean fields. All the occurring integrals induced by the number projection are performed analytically after writing the various overlap and energy matrices in the random phase approximation equation as polynomials in the gauge angle. In the limit of a large number of particles the well-known pairing vibration matrix elements are recovered. We also present a new analytically number projected variational equation for the number conserving pairing problem

On the Faddeev-Yacubovsky model of four nucleon scattering problem with account of spin and isospin

International Nuclear Information System (INIS)

Sharma, V.K.

1976-01-01

The Faddeev-Yacubovsky model of four nucleons taking into account their spin and isospin with the two-channel resonating group approximation, is considered. In this approximation, one employs a completely antisymmetric wave function which can be written as the clustering of d + d and n+He 3 (or p+H 3 ) systems with antisymmetric spin isospin states. The two-nucleon interactions used are of the separable Yamaguchi form in Ssub(1)sup(3) and Ssub(0)sup(3) states. The equations for the states with quantum numbers S=0,1,2 T=0 are obtained. It is shown that with subsequent separable representation of two-particle t-matrix reduces the equations to a set of one-dimensional coupled integral equations. (author)

Phase conjugation with random fields and with deterministic and random scatterers

International Nuclear Information System (INIS)

Gbur, G.; Wolf, E.

1999-01-01

The theory of distortion correction by phase conjugation, developed since the discovery of this phenomenon many years ago, applies to situations when the field that is conjugated is monochromatic and the medium with which it interacts is deterministic. In this Letter a generalization of the theory is presented that applies to phase conjugation of partially coherent waves interacting with either deterministic or random weakly scattering nonabsorbing media. copyright 1999 Optical Society of America

Random-phase metasurfaces at optical wavelengths

DEFF Research Database (Denmark)

Pors, Anders; Ding, Fei; Chen, Yiting

2016-01-01

, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications...

Phase stability of random brasses: pseudopotential theory revisited

International Nuclear Information System (INIS)

Rahman, S.M.M.

1987-06-01

We review the theoretical development concerning the phase stability of random brasses. The introductory discussion of the subject embraces the rules of metallurgy in general, but we emphasize on the roles of electron-per-atom ratio in the major bulk of our discussion. Starting from the so-called rigid-band model the discussion goes up to the recent higher-order pseudopotential theory. The theoretical refinements within the pseudopotential framework are discussed briefly. The stability criteria of the random phases are analysed both in the static lattice and dynamic lattice approximations. (author). 71 refs, figs and tabs

Gravitationally induced zero modes of the Faddeev-Popov operator in the Coulomb gauge for Abelian gauge theories

Science.gov (United States)

Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio

2010-08-01

It is shown that on curved backgrounds, the Coulomb gauge Faddeev-Popov operator can have zero modes even in the Abelian case. These zero modes cannot be eliminated by restricting the path integral over a certain region in the space of gauge potentials. The conditions for the existence of these zero modes are studied for static spherically symmetric spacetimes in arbitrary dimensions. For this class of metrics, the general analytic expression of the metric components in terms of the zero modes is constructed. Such expression allows one to find the asymptotic behavior of background metrics, which induce zero modes in the Coulomb gauge, an interesting example being the three-dimensional anti-de Sitter spacetime. Some of the implications for quantum field theory on curved spacetimes are discussed.

Nonlinear diffuse scattering of the random-phased wave

International Nuclear Information System (INIS)

Kato, Yoshiaki; Arinaga, Shinji; Mima, Kunioki.

1983-01-01

First experimental observation of the nonlinear diffuse scattering is reported. This new effect was observed in the propagation of the random-phased wave through a nonlinear dielectric medium. This effect is ascribed to the diffusion of the wavevector of the electro-magnetic wave to the lateral direction due to the randomly distributed nonlinear increase in the refractive index. (author)

Faddeev Treatment of the Quasi-Bound and Scattering States in the K¯NN−πΣN System: New Results

International Nuclear Information System (INIS)

Shevchenko, N.V.

2014-01-01

A chiral-motivated K¯N−πΣ−πΛ potential was constructed and used in Faddeev calculations of different characteristics of K¯NN−πΣN system. First of all, binding energy and width of the K − pp quasi-bound state were newly obtained. The low-energy K − d scattering amplitudes, including scattering length, together with the 1s level shift and width of kaonic deuterium were calculated. Comparison with the results obtained with the phenomenological K¯N−πΣ potential demonstrates that the chiral-motivated potential gives more shallow K − pp state, while the characteristics of K − d system are less sensitive to the form of K¯N interaction. (author)

States of ρB{sup *} anti B{sup *} with J = 3 within the fixed center approximation to Faddeev equations

Energy Technology Data Exchange (ETDEWEB)

Bayar, M. [Kocaeli University, Department of Physics, Izmit (Turkey); Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Aptdo. 22085, Valencia (Spain); Fernandez-Soler, P.; Sun, Zhi-Feng; Oset, E. [Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Aptdo. 22085, Valencia (Spain)

2016-04-15

In this work we study the ρB{sup *} anti B{sup *} three-body system solving the Faddeev equations in the fixed center approximation. We assume the B{sup *} anti B{sup *} system forming a cluster, and in terms of the two-body ρB{sup *} unitarized scattering amplitudes in the local hidden gauge approach we find a new I(J{sup PC}) = 1(3{sup -}) state. The mass of the new state corresponds to a two-particle invariant mass of the ρB{sup *} system close to the resonant energy of the *, indicating that the role of this J = 2 resonance is important in the dynamical generation of the new state. (orig.)

Randomly displaced phase distribution design and its advantage in page-data recording of Fourier transform holograms.

Science.gov (United States)

Emoto, Akira; Fukuda, Takashi

2013-02-20

For Fourier transform holography, an effective random phase distribution with randomly displaced phase segments is proposed for obtaining a smooth finite optical intensity distribution in the Fourier transform plane. Since unitary phase segments are randomly distributed in-plane, the blanks give various spatial frequency components to an image, and thus smooth the spectrum. Moreover, by randomly changing the phase segment size, spike generation from the unitary phase segment size in the spectrum can be reduced significantly. As a result, a smooth spectrum including sidebands can be formed at a relatively narrow extent. The proposed phase distribution sustains the primary functions of a random phase mask for holographic-data recording and reconstruction. Therefore, this distribution is expected to find applications in high-density holographic memory systems, replacing conventional random phase mask patterns.

Random-phase approximation and broken symmetry

International Nuclear Information System (INIS)

Davis, E.D.; Heiss, W.D.

1986-01-01

The validity of the random-phase approximation (RPA) in broken-symmetry bases is tested in an appropriate many-body system for which exact solutions are available. Initially the regions of stability of the self-consistent quasiparticle bases in this system are established and depicted in a 'phase' diagram. It is found that only stable bases can be used in an RPA calculation. This is particularly true for those RPA modes which are not associated with the onset of instability of the basis; it is seen that these modes do not describe any excited state when the basis is unstable, although from a formal point of view they remain acceptable. The RPA does well in a stable broken-symmetry basis provided one is not too close to a point where a phase transition occurs. This is true for both energies and matrix elements. (author)

Enhancing Security of Double Random Phase Encoding Based on Random S-Box

Science.gov (United States)

Girija, R.; Singh, Hukum

2018-06-01

In this paper, we propose a novel asymmetric cryptosystem for double random phase encoding (DRPE) using random S-Box. While utilising S-Box separately is not reliable and DRPE does not support non-linearity, so, our system unites the effectiveness of S-Box with an asymmetric system of DRPE (through Fourier transform). The uniqueness of proposed cryptosystem lies on employing high sensitivity dynamic S-Box for our DRPE system. The randomness and scalability achieved due to applied technique is an additional feature of the proposed solution. The firmness of random S-Box is investigated in terms of performance parameters such as non-linearity, strict avalanche criterion, bit independence criterion, linear and differential approximation probabilities etc. S-Boxes convey nonlinearity to cryptosystems which is a significant parameter and very essential for DRPE. The strength of proposed cryptosystem has been analysed using various parameters such as MSE, PSNR, correlation coefficient analysis, noise analysis, SVD analysis, etc. Experimental results are conferred in detail to exhibit proposed cryptosystem is highly secure.

Security enhancement of double random phase encoding using rear-mounted phase masking

Science.gov (United States)

Chen, Junxin; Zhang, Yu; Li, Jinchang; Zhang, Li-bo

2018-02-01

In this paper, a security enhancement for double random phase encoding (DRPE) by introducing a rear-mounted phase masking procedure is presented. Based on exhaustively studying the cryptanalysis achievements of DRPE and its variants, invalidation of the second lens, which plays a critical role in cryptanalyzing processes, is concluded. The improved system can exploit the security potential of the second lens and consequently strengthen the security of DRPE. Experimental results and security analyses are presented in detail to demonstrate the security potential of the proposed cryptosystem.

Nonequilibrium phase transition in directed small-world-Voronoi-Delaunay random lattices

International Nuclear Information System (INIS)

Lima, F.W.S.

2016-01-01

On directed small-world-Voronoi-Delaunay random lattices in two dimensions with quenched connectivity disorder we study the critical properties of the dynamics evolution of public opinion in social influence networks using a simple spin-like model. The system is treated by applying Monte Carlo simulations. We show that directed links on these random lattices may lead to phase diagram with first- and second-order social phase transitions out of equilibrium. (paper)

Deep learning the quantum phase transitions in random two-dimensional electron systems

International Nuclear Information System (INIS)

Ohtsuki, Tomoki; Ohtsuki, Tomi

2016-01-01

Random electron systems show rich phases such as Anderson insulator, diffusive metal, quantum Hall and quantum anomalous Hall insulators, Weyl semimetal, as well as strong/weak topological insulators. Eigenfunctions of each matter phase have specific features, but owing to the random nature of systems, determining the matter phase from eigenfunctions is difficult. Here, we propose the deep learning algorithm to capture the features of eigenfunctions. Localization-delocalization transition, as well as disordered Chern insulator-Anderson insulator transition, is discussed. (author)

Quasilinear theory without the random phase approximation

International Nuclear Information System (INIS)

Weibel, E.S.; Vaclavik, J.

1980-08-01

The system of quasilinear equations is derived without making use of the random phase approximation. The fluctuating quantities are described by the autocorrelation function of the electric field using the techniques of Fourier analysis. The resulting equations posses the necessary conservation properties, but comprise new terms which hitherto have been lost in the conventional derivations

Large leptonic Dirac CP phase from broken democracy with random perturbations

Science.gov (United States)

Ge, Shao-Feng; Kusenko, Alexander; Yanagida, Tsutomu T.

2018-06-01

A large value of the leptonic Dirac CP phase can arise from broken democracy, where the mass matrices are democratic up to small random perturbations. Such perturbations are a natural consequence of broken residual S3 symmetries that dictate the democratic mass matrices at leading order. With random perturbations, the leptonic Dirac CP phase has a higher probability to attain a value around ± π / 2. Comparing with the anarchy model, broken democracy can benefit from residual S3 symmetries, and it can produce much better, realistic predictions for the mass hierarchy, mixing angles, and Dirac CP phase in both quark and lepton sectors. Our approach provides a general framework for a class of models in which a residual symmetry determines the general features at leading order, and where, in the absence of other fundamental principles, the symmetry breaking appears in the form of random perturbations.

Deterministic matrices matching the compressed sensing phase transitions of Gaussian random matrices

Science.gov (United States)

Monajemi, Hatef; Jafarpour, Sina; Gavish, Matan; Donoho, David L.; Ambikasaran, Sivaram; Bacallado, Sergio; Bharadia, Dinesh; Chen, Yuxin; Choi, Young; Chowdhury, Mainak; Chowdhury, Soham; Damle, Anil; Fithian, Will; Goetz, Georges; Grosenick, Logan; Gross, Sam; Hills, Gage; Hornstein, Michael; Lakkam, Milinda; Lee, Jason; Li, Jian; Liu, Linxi; Sing-Long, Carlos; Marx, Mike; Mittal, Akshay; Monajemi, Hatef; No, Albert; Omrani, Reza; Pekelis, Leonid; Qin, Junjie; Raines, Kevin; Ryu, Ernest; Saxe, Andrew; Shi, Dai; Siilats, Keith; Strauss, David; Tang, Gary; Wang, Chaojun; Zhou, Zoey; Zhu, Zhen

2013-01-01

In compressed sensing, one takes samples of an N-dimensional vector using an matrix A, obtaining undersampled measurements . For random matrices with independent standard Gaussian entries, it is known that, when is k-sparse, there is a precisely determined phase transition: for a certain region in the (,)-phase diagram, convex optimization typically finds the sparsest solution, whereas outside that region, it typically fails. It has been shown empirically that the same property—with the same phase transition location—holds for a wide range of non-Gaussian random matrix ensembles. We report extensive experiments showing that the Gaussian phase transition also describes numerous deterministic matrices, including Spikes and Sines, Spikes and Noiselets, Paley Frames, Delsarte-Goethals Frames, Chirp Sensing Matrices, and Grassmannian Frames. Namely, for each of these deterministic matrices in turn, for a typical k-sparse object, we observe that convex optimization is successful over a region of the phase diagram that coincides with the region known for Gaussian random matrices. Our experiments considered coefficients constrained to for four different sets , and the results establish our finding for each of the four associated phase transitions. PMID:23277588

3D Multisource Full‐Waveform Inversion using Dynamic Random Phase Encoding

KAUST Repository

Boonyasiriwat, Chaiwoot

2010-10-17

We have developed a multisource full‐waveform inversion algorithm using a dynamic phase encoding strategy with dual‐randomization—both the position and polarity of simultaneous sources are randomized and changed every iteration. The dynamic dual‐randomization is used to promote the destructive interference of crosstalk noise resulting from blending a large number of common shot gathers into a supergather. We compare our multisource algorithm with various algorithms in a numerical experiment using the 3D SEG/EAGE overthrust model and show that our algorithm provides a higher‐quality velocity tomogram than the other methods that use only monorandomization. This suggests that increasing the degree of randomness in phase encoding should improve the quality of the inversion result.

Effects of systematic phase errors on optimized quantum random-walk search algorithm

International Nuclear Information System (INIS)

Zhang Yu-Chao; Bao Wan-Su; Wang Xiang; Fu Xiang-Qun

2015-01-01

This study investigates the effects of systematic errors in phase inversions on the success rate and number of iterations in the optimized quantum random-walk search algorithm. Using the geometric description of this algorithm, a model of the algorithm with phase errors is established, and the relationship between the success rate of the algorithm, the database size, the number of iterations, and the phase error is determined. For a given database size, we obtain both the maximum success rate of the algorithm and the required number of iterations when phase errors are present in the algorithm. Analyses and numerical simulations show that the optimized quantum random-walk search algorithm is more robust against phase errors than Grover’s algorithm. (paper)

Ultra-fast quantum randomness generation by accelerated phase diffusion in a pulsed laser diode.

Science.gov (United States)

Abellán, C; Amaya, W; Jofre, M; Curty, M; Acín, A; Capmany, J; Pruneri, V; Mitchell, M W

2014-01-27

We demonstrate a high bit-rate quantum random number generator by interferometric detection of phase diffusion in a gain-switched DFB laser diode. Gain switching at few-GHz frequencies produces a train of bright pulses with nearly equal amplitudes and random phases. An unbalanced Mach-Zehnder interferometer is used to interfere subsequent pulses and thereby generate strong random-amplitude pulses, which are detected and digitized to produce a high-rate random bit string. Using established models of semiconductor laser field dynamics, we predict a regime of high visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These are confirmed by measurement of pulse power statistics at the output of the interferometer. Using a 5.825 GHz excitation rate and 14-bit digitization, we observe 43 Gbps quantum randomness generation.

Variational random phase approximation for the anharmonic oscillator

International Nuclear Information System (INIS)

Dukelsky, J.; Schuck, P.

1990-04-01

The recently derived Variational Random Phase Approximation is examined using the anharmonic oscillator model. Special attention is paid to the ground state RPA wave function and the convergence of the proposed truncation scheme to obtain the diagonal density matrix. Comparison with the standard Coupled Cluster method is made

Does quasi-long-range order in the two-dimensional XY model really survive weak random phase fluctuations?

International Nuclear Information System (INIS)

Mudry, Christopher; Wen Xiaogang

1999-01-01

Effective theories for random critical points are usually non-unitary, and thus may contain relevant operators with negative scaling dimensions. To study the consequences of the existence of negative-dimensional operators, we consider the random-bond XY model. It has been argued that the XY model on a square lattice, when weakly perturbed by random phases, has a quasi-long-range ordered phase (the random spin wave phase) at sufficiently low temperatures. We show that infinitely many relevant perturbations to the proposed critical action for the random spin wave phase were omitted in all previous treatments. The physical origin of these perturbations is intimately related to the existence of broadly distributed correlation functions. We find that those relevant perturbations do enter the Renormalization Group equations, and affect critical behavior. This raises the possibility that the random XY model has no quasi-long-range ordered phase and no Kosterlitz-Thouless (KT) phase transition

Revealing novel quantum phases in quantum antiferromagnets on random lattices

Directory of Open Access Journals (Sweden)

R. Yu

2009-01-01

Full Text Available Quantum magnets represent an ideal playground for the controlled realization of novel quantum phases and of quantum phase transitions. The Hamiltonian of the system can be indeed manipulated by applying a magnetic field or pressure on the sample. When doping the system with non-magnetic impurities, novel inhomogeneous phases emerge from the interplay between geometric randomness and quantum fluctuations. In this paper we review our recent work on quantum phase transitions and novel quantum phases realized in disordered quantum magnets. The system inhomogeneity is found to strongly affect phase transitions by changing their universality class, giving the transition a novel, quantum percolative nature. Such transitions connect conventionally ordered phases to unconventional, quantum disordered ones - quantum Griffiths phases, magnetic Bose glass phases - exhibiting gapless spectra associated with low-energy localized excitations.

Optical image transformation and encryption by phase-retrieval-based double random-phase encoding and compressive ghost imaging

Science.gov (United States)

Yuan, Sheng; Yang, Yangrui; Liu, Xuemei; Zhou, Xin; Wei, Zhenzhuo

2018-01-01

An optical image transformation and encryption scheme is proposed based on double random-phase encoding (DRPE) and compressive ghost imaging (CGI) techniques. In this scheme, a secret image is first transformed into a binary image with the phase-retrieval-based DRPE technique, and then encoded by a series of random amplitude patterns according to the ghost imaging (GI) principle. Compressive sensing, corrosion and expansion operations are implemented to retrieve the secret image in the decryption process. This encryption scheme takes the advantage of complementary capabilities offered by the phase-retrieval-based DRPE and GI-based encryption techniques. That is the phase-retrieval-based DRPE is used to overcome the blurring defect of the decrypted image in the GI-based encryption, and the CGI not only reduces the data amount of the ciphertext, but also enhances the security of DRPE. Computer simulation results are presented to verify the performance of the proposed encryption scheme.

Ultrafast quantum random number generation based on quantum phase fluctuations.

Science.gov (United States)

Xu, Feihu; Qi, Bing; Ma, Xiongfeng; Xu, He; Zheng, Haoxuan; Lo, Hoi-Kwong

2012-05-21

A quantum random number generator (QRNG) can generate true randomness by exploiting the fundamental indeterminism of quantum mechanics. Most approaches to QRNG employ single-photon detection technologies and are limited in speed. Here, we experimentally demonstrate an ultrafast QRNG at a rate over 6 Gbits/s based on the quantum phase fluctuations of a laser operating near threshold. Moreover, we consider a potential adversary who has partial knowledge on the raw data and discuss how one can rigorously remove such partial knowledge with postprocessing. We quantify the quantum randomness through min-entropy by modeling our system and employ two randomness extractors--Trevisan's extractor and Toeplitz-hashing--to distill the randomness, which is information-theoretically provable. The simplicity and high-speed of our experimental setup show the feasibility of a robust, low-cost, high-speed QRNG.

The random phase transducer in ultrasonic NDT of coarse grain stainless steel

International Nuclear Information System (INIS)

Bordier, J.M.; Fink, M.; Le Brun, A.; Cohen-Tenoudji, F.

1993-11-01

Ultrasonic NDT of cast stainless steel is known to be difficult due to a huge loss of focussing of the ultrasonic beam, and to a high level speckle noise generated by the coarse grain structure. In this paper, we describe the principle of the ultrasonic random phase transducer. Experimental results are compared with those obtained with a standard spatial compound technique. We show that the random phase transducer is a good tool to characterize the multiple scattering process generated by these materials. (authors). 7 figs., 11 refs

Phase diagram and tricritical behavior of an metamagnet in uniform and random fields

International Nuclear Information System (INIS)

Liang Yaqiu; Wei Guozhu; Xu Xiaojuan; Song Guoli

2010-01-01

A two-sublattice Ising metamagnet in both uniform and random fields is studied within the mean-field approach based on Bogoliubov's inequality for the Gibbs free energy. We show that the qualitative features of the phase diagrams are dependent on the parameters of the model and the uniform field values. The tricritical point and reentrant phenomenon can be observed on the phase diagram. The reentrance is due to the competition between uniform and random interactions.

Validation of the k-filtering technique for a signal composed of random-phase plane waves and non-random coherent structures

Directory of Open Access Journals (Sweden)

O. W. Roberts

2014-12-01

Full Text Available Recent observations of astrophysical magnetic fields have shown the presence of fluctuations being wave-like (propagating in the plasma frame and those described as being structure-like (advected by the plasma bulk velocity. Typically with single-spacecraft missions it is impossible to differentiate between these two fluctuations, due to the inherent spatio-temporal ambiguity associated with a single point measurement. However missions such as Cluster which contain multiple spacecraft have allowed for temporal and spatial changes to be resolved, using techniques such as k filtering. While this technique does not assume Taylor's hypothesis it requires both weak stationarity of the time series and that the fluctuations can be described by a superposition of plane waves with random phases. In this paper we test whether the method can cope with a synthetic signal which is composed of a combination of non-random-phase coherent structures with a mean radius d and a mean separation λ, as well as plane waves with random phase.

Phase-Image Encryption Based on 3D-Lorenz Chaotic System and Double Random Phase Encoding

Science.gov (United States)

Sharma, Neha; Saini, Indu; Yadav, AK; Singh, Phool

2017-12-01

In this paper, an encryption scheme for phase-images based on 3D-Lorenz chaotic system in Fourier domain under the 4f optical system is presented. The encryption scheme uses a random amplitude mask in the spatial domain and a random phase mask in the frequency domain. Its inputs are phase-images, which are relatively more secure as compared to the intensity images because of non-linearity. The proposed scheme further derives its strength from the use of 3D-Lorenz transform in the frequency domain. Although the experimental setup for optical realization of the proposed scheme has been provided, the results presented here are based on simulations on MATLAB. It has been validated for grayscale images, and is found to be sensitive to the encryption parameters of the Lorenz system. The attacks analysis shows that the key-space is large enough to resist brute-force attack, and the scheme is also resistant to the noise and occlusion attacks. Statistical analysis and the analysis based on correlation distribution of adjacent pixels have been performed to test the efficacy of the encryption scheme. The results have indicated that the proposed encryption scheme possesses a high level of security.

Simultaneous transmission for an encrypted image and a double random-phase encryption key

Science.gov (United States)

Yuan, Sheng; Zhou, Xin; Li, Da-Hai; Zhou, Ding-Fu

2007-06-01

We propose a method to simultaneously transmit double random-phase encryption key and an encrypted image by making use of the fact that an acceptable decryption result can be obtained when only partial data of the encrypted image have been taken in the decryption process. First, the original image data are encoded as an encrypted image by a double random-phase encryption technique. Second, a double random-phase encryption key is encoded as an encoded key by the Rivest-Shamir-Adelman (RSA) public-key encryption algorithm. Then the amplitude of the encrypted image is modulated by the encoded key to form what we call an encoded image. Finally, the encoded image that carries both the encrypted image and the encoded key is delivered to the receiver. Based on such a method, the receiver can have an acceptable result and secure transmission can be guaranteed by the RSA cipher system.

Atomic structure calculations using the relativistic random phase approximation

International Nuclear Information System (INIS)

Cheng, K.T.; Johnson, W.R.

1981-01-01

A brief review is given for the relativistic random phase approximation (RRPA) applied to atomic transition problems. Selected examples of RRPA calculations on discrete excitations and photoionization are given to illustrate the need of relativistic many-body theories in dealing with atomic processes where both relativity and correlation are important

Lensless digital holography with diffuse illumination through a pseudo-random phase mask.

Science.gov (United States)

Bernet, Stefan; Harm, Walter; Jesacher, Alexander; Ritsch-Marte, Monika

2011-12-05

Microscopic imaging with a setup consisting of a pseudo-random phase mask, and an open CMOS camera, without an imaging objective, is demonstrated. The pseudo random phase mask acts as a diffuser for an incoming laser beam, scattering a speckle pattern to a CMOS chip, which is recorded once as a reference. A sample which is afterwards inserted somewhere in the optical beam path changes the speckle pattern. A single (non-iterative) image processing step, comparing the modified speckle pattern with the previously recorded one, generates a sharp image of the sample. After a first calibration the method works in real-time and allows quantitative imaging of complex (amplitude and phase) samples in an extended three-dimensional volume. Since no lenses are used, the method is free from lens abberations. Compared to standard inline holography the diffuse sample illumination improves the axial sectioning capability by increasing the effective numerical aperture in the illumination path, and it suppresses the undesired so-called twin images. For demonstration, a high resolution spatial light modulator (SLM) is programmed to act as the pseudo-random phase mask. We show experimental results, imaging microscopic biological samples, e.g. insects, within an extended volume at a distance of 15 cm with a transverse and longitudinal resolution of about 60 μm and 400 μm, respectively.

Hacking on decoy-state quantum key distribution system with partial phase randomization

Science.gov (United States)

Sun, Shi-Hai; Jiang, Mu-Sheng; Ma, Xiang-Chun; Li, Chun-Yan; Liang, Lin-Mei

2014-04-01

Quantum key distribution (QKD) provides means for unconditional secure key transmission between two distant parties. However, in practical implementations, it suffers from quantum hacking due to device imperfections. Here we propose a hybrid measurement attack, with only linear optics, homodyne detection, and single photon detection, to the widely used vacuum + weak decoy state QKD system when the phase of source is partially randomized. Our analysis shows that, in some parameter regimes, the proposed attack would result in an entanglement breaking channel but still be able to trick the legitimate users to believe they have transmitted secure keys. That is, the eavesdropper is able to steal all the key information without discovered by the users. Thus, our proposal reveals that partial phase randomization is not sufficient to guarantee the security of phase-encoding QKD systems with weak coherent states.

Hacking on decoy-state quantum key distribution system with partial phase randomization.

Science.gov (United States)

Sun, Shi-Hai; Jiang, Mu-Sheng; Ma, Xiang-Chun; Li, Chun-Yan; Liang, Lin-Mei

2014-04-23

Quantum key distribution (QKD) provides means for unconditional secure key transmission between two distant parties. However, in practical implementations, it suffers from quantum hacking due to device imperfections. Here we propose a hybrid measurement attack, with only linear optics, homodyne detection, and single photon detection, to the widely used vacuum + weak decoy state QKD system when the phase of source is partially randomized. Our analysis shows that, in some parameter regimes, the proposed attack would result in an entanglement breaking channel but still be able to trick the legitimate users to believe they have transmitted secure keys. That is, the eavesdropper is able to steal all the key information without discovered by the users. Thus, our proposal reveals that partial phase randomization is not sufficient to guarantee the security of phase-encoding QKD systems with weak coherent states.

Static correlation beyond the random phase approximation

DEFF Research Database (Denmark)

Olsen, Thomas; Thygesen, Kristian Sommer

2014-01-01

derived from Hedin's equations (Random Phase Approximation (RPA), Time-dependent Hartree-Fock (TDHF), Bethe-Salpeter equation (BSE), and Time-Dependent GW) all reproduce the correct dissociation limit. We also show that the BSE improves the correlation energies obtained within RPA and TDHF significantly...... and confirms that BSE greatly improves the RPA and TDHF results despite the fact that the BSE excitation spectrum breaks down in the dissociation limit. In contrast, second order screened exchange gives a poor description of the dissociation limit, which can be attributed to the fact that it cannot be derived...

Beyond the random phase approximation

DEFF Research Database (Denmark)

Olsen, Thomas; Thygesen, Kristian S.

2013-01-01

We assess the performance of a recently proposed renormalized adiabatic local density approximation (rALDA) for ab initio calculations of electronic correlation energies in solids and molecules. The method is an extension of the random phase approximation (RPA) derived from time-dependent density...... functional theory and the adiabatic connection fluctuation-dissipation theorem and contains no fitted parameters. The new kernel is shown to preserve the accurate description of dispersive interactions from RPA while significantly improving the description of short-range correlation in molecules, insulators......, and metals. For molecular atomization energies, the rALDA is a factor of 7 better than RPA and a factor of 4 better than the Perdew-Burke-Ernzerhof (PBE) functional when compared to experiments, and a factor of 3 (1.5) better than RPA (PBE) for cohesive energies of solids. For transition metals...

Interaction between local parameters of two-phase flow and random forces on a cylinder

International Nuclear Information System (INIS)

Sylviane Pascal-Ribot; Yves Blanchet; Franck Baj; Phillippe Piteau

2005-01-01

Full text of publication follows: In the frame of assessments of steam generator tube bundle vibrations, a study was conducted in order to investigate the effects of an air/water flow on turbulent buffeting forces induced on a cylinder. The main purpose is to relate the physical parameters characterizing an air/water two-phase crossflow with the structural loading of a fixed cylindrical tube. In this first approach, the experiments are carried out in a rectangular acrylic test section supplied with a vertical upward bubbly flow. This flow is transversally impeded by a fixed rigid 12,15 mm diameter cylinder. Different turbulence grids are used in order to modify two-phase characteristics such as bubble diameter, void fraction profile, fluctuation parameters. Preliminarily, a dimensional analysis of fluid-structure interaction under two-phase turbulent solicitations has enabled to identify a list of physically relevant variables which must be measured to evaluate the random forces. The meaning of these relevant parameters as well as the effect of flow patterns are discussed. Direct measurements of two-phase flow parameters are performed simultaneously with measurements of forces exerted on the cylinder. The main descriptive parameters of a two-phase flow are measured using a bi-optical probe, in particular void fraction profiles, interfacial velocities, bubble diameters, void fraction fluctuations. In the same time, the magnitude of random forces caused by two-phase flow is measured with a force transducer. A thorough analysis of the experimental data is then undertaken in order to correlate physical two-phase mechanisms with the random forces exerted on the cylinder. The hypotheses made while applying the dimensional analysis are verified and their pertinence is discussed. Finally, physical parameters involved in random buffeting forces applied on a transverse tube are proposed to scale the spectral magnitude of these forces and comparisons with other authors

Photoabsorption for helium, lithium, and beryllium atoms in the random-phase approximation with exchange

International Nuclear Information System (INIS)

Amusia, M.Y.; Cherepkov, N.A.; Zivanovic, D.; Radojevic, V.

1976-01-01

The photoionization cross sections and the oscillator strengths for helium, lithium, and beryllium atoms are calculated in the framework of the random-phase approximation with exchange. The energy-level shift for discrete transitions is taken into account consistently in this approximation. The results are compared with other many-body calculations and with experimental data. The comparison shows that the random-phase approximation with exchange can even be used for systems with a small number of particles

3D Multisource Full‐Waveform Inversion using Dynamic Random Phase Encoding

KAUST Repository

Boonyasiriwat, Chaiwoot; Schuster, Gerard T.

2010-01-01

We have developed a multisource full‐waveform inversion algorithm using a dynamic phase encoding strategy with dual‐randomization—both the position and polarity of simultaneous sources are randomized and changed every iteration. The dynamic dual

Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase-II: A Phase II Randomized Trial.

Science.gov (United States)

Okonkwo, David O; Shutter, Lori A; Moore, Carol; Temkin, Nancy R; Puccio, Ava M; Madden, Christopher J; Andaluz, Norberto; Chesnut, Randall M; Bullock, M Ross; Grant, Gerald A; McGregor, John; Weaver, Michael; Jallo, Jack; LeRoux, Peter D; Moberg, Dick; Barber, Jason; Lazaridis, Christos; Diaz-Arrastia, Ramon R

2017-11-01

A relationship between reduced brain tissue oxygenation and poor outcome following severe traumatic brain injury has been reported in observational studies. We designed a Phase II trial to assess whether a neurocritical care management protocol could improve brain tissue oxygenation levels in patients with severe traumatic brain injury and the feasibility of a Phase III efficacy study. Randomized prospective clinical trial. Ten ICUs in the United States. One hundred nineteen severe traumatic brain injury patients. Patients were randomized to treatment protocol based on intracranial pressure plus brain tissue oxygenation monitoring versus intracranial pressure monitoring alone. Brain tissue oxygenation data were recorded in the intracranial pressure -only group in blinded fashion. Tiered interventions in each arm were specified and impact on intracranial pressure and brain tissue oxygenation measured. Monitors were removed if values were normal for 48 hours consecutively, or after 5 days. Outcome was measured at 6 months using the Glasgow Outcome Scale-Extended. A management protocol based on brain tissue oxygenation and intracranial pressure monitoring reduced the proportion of time with brain tissue hypoxia after severe traumatic brain injury (0.45 in intracranial pressure-only group and 0.16 in intracranial pressure plus brain tissue oxygenation group; p injury after severe traumatic brain injury based on brain tissue oxygenation and intracranial pressure values was consistent with reduced mortality and increased proportions of patients with good recovery compared with intracranial pressure-only management; however, the study was not powered for clinical efficacy. Management of severe traumatic brain injury informed by multimodal intracranial pressure and brain tissue oxygenation monitoring reduced brain tissue hypoxia with a trend toward lower mortality and more favorable outcomes than intracranial pressure-only treatment. A Phase III randomized trial to assess

Application of the Faddeev-Watson expansion to thermal collisions of Rydberg atoms with neutral particles

International Nuclear Information System (INIS)

de Prunele, E.

1983-01-01

The Faddeev-Watson expansion (FWE) for the T operator is applied to the study of thermal collisions between Rydberg atom and neutral atom. These collisions are considered as a three-body problem (the perturber, the Rydberg electron, and its parent core) and it is assumed, as already done in most theoretical works dealing with Rydberg-atom--atom collisions, that the core-perturber interaction can be neglected. Then the evaluation of the FWE first- and second-order terms is made tractable by using an appropriate separable potential for the Rydberg-electron--perturber interaction. The evaluation of the second-order term allows us to estimate the importance of taking into account explicitly the Rydberg-electron--core interaction in the expression of the (three-body) T operator for the thermal collisions considered. Detailed calculations for the process Rb(n, l = 0)+He →Rb(n',l')+He are presented and discussed. The FWE second-order term has been evaluated for the first time by taking the (two-body) t operator associated with the Rydberg atom (valence electron plus parent core) as the Coulomb potential. The contribution of the FWE second-order term to the scattering amplitude decreases as n increases and is found especially significant when both the momentum transfers involved in the collision are large and the values of l and l' are small

Fractional Fourier domain optical image hiding using phase retrieval algorithm based on iterative nonlinear double random phase encoding.

Science.gov (United States)

Wang, Xiaogang; Chen, Wen; Chen, Xudong

2014-09-22

We present a novel image hiding method based on phase retrieval algorithm under the framework of nonlinear double random phase encoding in fractional Fourier domain. Two phase-only masks (POMs) are efficiently determined by using the phase retrieval algorithm, in which two cascaded phase-truncated fractional Fourier transforms (FrFTs) are involved. No undesired information disclosure, post-processing of the POMs or digital inverse computation appears in our proposed method. In order to achieve the reduction in key transmission, a modified image hiding method based on the modified phase retrieval algorithm and logistic map is further proposed in this paper, in which the fractional orders and the parameters with respect to the logistic map are regarded as encryption keys. Numerical results have demonstrated the feasibility and effectiveness of the proposed algorithms.

Reduction of Musical Noise in Spectral Subtraction Method Using Subframe Phase Randomization

Energy Technology Data Exchange (ETDEWEB)

Seok, J.W.; Bae, K.S. [Kyungpook National University, Taegu (Korea)

1999-06-01

The Subframe phase randomization method is applied to the spectral subtraction method to reduce the musical noise in nonvoicing region after speech enhancement. The musical noise in the spectral subtraction method is the result of the narrowband tonal components that appearing somewhat periodically in the spectrogram of unvoiced and silence regions. Thus each synthesis frame in nonvoicing region is divided into several subframes to broaden the narrowband spectrum, and then phases of silence and unvoiced regions are randomized to eliminate the tonal components in the spectrum while keeping the shape of the amplitude spectrum. Performance assessments based on visual inspection of spectrogram, objective measure, and informal subjective listening tests demonstrate the superiority of the proposed algorithm. (author). 7 refs., 5 figs.

The phase diagrams of a ferromagnetic thin film in a random magnetic field

Energy Technology Data Exchange (ETDEWEB)

Zaim, N.; Zaim, A., E-mail: ah_zaim@yahoo.fr; Kerouad, M., E-mail: m.kerouad@fs-umi.ac.ma

2016-10-07

In this paper, the magnetic properties and the phase diagrams of a ferromagnetic thin film with a thickness N in a random magnetic field (RMF) are investigated by using the Monte Carlo simulation technique based on the Metropolis algorithm. The effects of the RMF and the surface exchange interaction on the critical behavior are studied. A variety of multicritical points such as tricritical points, isolated critical points, and triple points are obtained. It is also found that the double reentrant phenomenon can appear for appropriate values of the system parameters. - Highlights: • Phase diagrams of a ferromagnetic thin film are examined by the Monte Carlo simulation. • The effect of the random magnetic field on the magnetic properties is studied. • Different types of the phase diagrams are obtained. • The dependence of the magnetization and susceptibility on the temperature are investigated.

Thermal behavior for a nanoscale two ferromagnetic phase system based on random anisotropy model

International Nuclear Information System (INIS)

Muraca, D.; Sanchez, F.H.; Pampillo, L.G.; Saccone, F.D.

2010-01-01

Advances in theory that explain the magnetic behavior as function of temperature for two phase nanocrystalline soft magnetic materials are presented. The theory developed is based on the well known random anisotropy model, which includes the crystalline exchange stiffness and anisotropy energies in both amorphous and crystalline phases. The phenomenological behavior of the coercivity was obtained in the temperature range between the amorphous phase Curie temperature and the crystalline phase one.

Path integral in Snyder space

Energy Technology Data Exchange (ETDEWEB)

Mignemi, S., E-mail: smignemi@unica.it [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy); Štrajn, R. [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy)

2016-04-29

The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

Path integral in Snyder space

International Nuclear Information System (INIS)

Mignemi, S.; Štrajn, R.

2016-01-01

The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

Magnetic transitions and phases in random-anisotropy magnets

International Nuclear Information System (INIS)

Sellmyer, D.J.; Nafis, S.; O'Shea, M.J.

1988-01-01

The generality and universality of the Ising spin-glass-like phase transitions observed in several rare-earth, random-anisotropy magnets are discussed. Some uncertainties and practical problems in determining critical exponents are considered, and a comparison is made to insulating spin glasses and crystalline spin glasses where an apparent anisotropy-induced crossover from Heisenberg to Ising-like behavior is seen. The observation of a reentrant transition in a weak anisotropy system and its correlation with the theory of Chudnovsky, Saslow, and Serota [Phys. Rev. B 33, 251 (1986)] for the correlated spin glass is discussed

Magnetic transitions and phases in random-anisotropy magnets

Science.gov (United States)

Sellmyer, D. J.; Nafis, S.; O'Shea, M. J.

1988-04-01

The generality and universality of the Ising spin-glass-like phase transitions observed in several rare-earth, random-anisotropy magnets are discussed. Some uncertainties and practical problems in determining critical exponents are considered, and a comparison is made to insulating spin glasses and crystalline spin glasses where an apparent anisotropy-induced crossover from Heisenberg to Ising-like behavior is seen. The observation of a reentrant transition in a weak anisotropy system and its correlation with the theory of Chudnovsky, Saslow, and Serota [Phys. Rev. B 33, 251 (1986)] for the correlated spin glass is discussed.

Effects of the randomly distributed magnetic field on the phase diagrams of the Ising Nanowire II: Continuous distributions

International Nuclear Information System (INIS)

Akıncı, Ümit

2012-01-01

The effect of the random magnetic field distribution on the phase diagrams and ground state magnetizations of the Ising nanowire has been investigated with effective field theory with correlations. Gaussian distribution has been chosen as a random magnetic field distribution. The variation of the phase diagrams with that distribution parameters has been obtained and some interesting results have been found such as disappearance of the reentrant behavior and first order transitions which appear in the case of discrete distributions. Also for single and double Gaussian distributions, ground state magnetizations for different distribution parameters have been determined which can be regarded as separate partially ordered phases of the system. - Highlights: ► We give the phase diagrams of the Ising nanowire under the continuous randomly distributed magnetic field. ► Ground state magnetization values obtained. ► Different partially ordered phases observed.

Phase-only asymmetric optical cryptosystem based on random modulus decomposition

Science.gov (United States)

Xu, Hongfeng; Xu, Wenhui; Wang, Shuaihua; Wu, Shaofan

2018-06-01

We propose a phase-only asymmetric optical cryptosystem based on random modulus decomposition (RMD). The cryptosystem is presented for effectively improving the capacity to resist various attacks, including the attack of iterative algorithms. On the one hand, RMD and phase encoding are combined to remove the constraints that can be used in the attacking process. On the other hand, the security keys (geometrical parameters) introduced by Fresnel transform can increase the key variety and enlarge the key space simultaneously. Numerical simulation results demonstrate the strong feasibility, security and robustness of the proposed cryptosystem. This cryptosystem will open up many new opportunities in the application fields of optical encryption and authentication.

Random phase approximation in relativistic approach

International Nuclear Information System (INIS)

Ma Zhongyu; Yang Ding; Tian Yuan; Cao Ligang

2009-01-01

Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application of the RPA in the description of dynamical properties of finite nuclei. The fully consistent relativistic RPA(RRPA) requires that the relativistic mean filed (RMF) wave function of the nucleus and the RRPA correlations are calculated in a same effective Lagrangian and the consistent treatment of the Dirac sea of negative energy states. The proper treatment of the single particle continuum with scattering asymptotic conditions in the RMF and RRPA is discussed. The full continuum spectrum can be described by the single particle Green's function and the relativistic continuum RPA is established. A separable form of the paring force is introduced in the relativistic quasi-particle RPA. (authors)

Deterministic matrices matching the compressed sensing phase transitions of Gaussian random matrices

OpenAIRE

Monajemi, Hatef; Jafarpour, Sina; Gavish, Matan; Donoho, David L.; Ambikasaran, Sivaram; Bacallado, Sergio; Bharadia, Dinesh; Chen, Yuxin; Choi, Young; Chowdhury, Mainak; Chowdhury, Soham; Damle, Anil; Fithian, Will; Goetz, Georges; Grosenick, Logan

2012-01-01

In compressed sensing, one takes samples of an N-dimensional vector using an matrix A, obtaining undersampled measurements . For random matrices with independent standard Gaussian entries, it is known that, when is k-sparse, there is a precisely determined phase transition: for a certain region in the (,)-phase diagram, convex optimization typically finds the sparsest solution, whereas outside that region, it typically fails. It has been shown empirically that the same property—with the ...

Dasatinib or imatinib in newly diagnosed chronic-phase chronic myeloid leukemia : 2-year follow-up from a randomized phase 3 trial (DASISION)

NARCIS (Netherlands)

Kantarjian, Hagop M.; Shah, Neil P.; Cortes, Jorge E.; Baccarani, Michele; Agarwal, Mohan B.; Soledad Undurraga, Maria; Wang, Jianxiang; Kassack Ipina, Juan Julio; Kim, Dong-Wook; Ogura, Michinori; Pavlovsky, Carolina; Junghanss, Christian; Milone, Jorge H.; Nicolini, Franck E.; Robak, Tadeusz; Van Droogenbroeck, Jan; Vellenga, Edo; Bradley-Garelik, M. Brigid; Zhu, Chao; Hochhaus, Andreas

2012-01-01

Dasatinib is a highly potent BCR-ABL inhibitor with established efficacy and safety in imatinib-resistant/-intolerant patients with chronic myeloid leukemia (CML). In the phase 3 DASISION trial, patients with newly diagnosed chronic-phase (CP) CML were randomized to receive dasatinib 100 mg (n =

Smoothing by spectral dispersion using random phase modulation for inertial confinement fusion

International Nuclear Information System (INIS)

Rothenberg, J.E.

1995-01-01

Numerical simulations of beam smoothing using random phase modulation and grating dispersion are presented. Spatial spectra of the target illumination show that significantly improved smoothing at low spatial frequency is achieved while maintaining uniform intensity in the laser amplifier

Calculation of thermodynamic properties using the random-phase approximation: alpha-N2

NARCIS (Netherlands)

Jansen, A.P.J.; Schoorl, R.

1988-01-01

The random-phase approximation (RPA) for molecular crystals is extended in order to calculate thermodynamic properties. A recursion formula for thermodynamic averages of products of mean-field excitation and deexcitation operators is derived. With this formula the thermodynamic average of any

Nanostructure-property relations for phase-change random access memory (PCRAM) line cells

NARCIS (Netherlands)

Kooi, B. J.; Oosthoek, J. L. M.; Verheijen, M. A.; Kaiser, M.; Jedema, F. J.; Gravesteijn, D. J.

2012-01-01

Phase-change random access memory (PCRAM) cells have been studied extensively using electrical characterization and rather limited by detailed structure characterization. The combination of these two characterization techniques has hardly been exploited and it is the focus of the present work.

Phase transitions in the random field Ising model in the presence of a transverse field

Energy Technology Data Exchange (ETDEWEB)

Dutta, A.; Chakrabarti, B.K. [Saha Institute of Nuclear Physics, Bidhannagar, Calcutta (India); Stinchcombe, R.B. [Saha Institute of Nuclear Physics, Bidhannagar, Calcutta (India); Department of Physics, Oxford (United Kingdom)

1996-09-07

We have studied the phase transition behaviour of the random field Ising model in the presence of a transverse (or tunnelling) field. The mean field phase diagram has been studied in detail, and in particular the nature of the transition induced by the tunnelling (transverse) field at zero temperature. Modified hyper-scaling relation for the zero-temperature transition has been derived using the Suzuki-Trotter formalism and a modified 'Harris criterion'. Mapping of the model to a randomly diluted antiferromagnetic Ising model in uniform longitudinal and transverse field is also given. (author)

Calculation of subLAMBDA sup 9 Be in an alpha-alpha-LAMBDA three-body model using the Faddeev equations

CERN Document Server

Oryu, S; Yamashita, H; Nakazawa, M; Kamada, H

2000-01-01

The hypernucleus subLAMBDA sup 9 Be is investigated in an alpha-alpha-LAMBDA three-body model using the Faddeev formalism. We use an alpha-alpha interaction in which the Pauli-forbidden states are correctly taken into account and we employ some phenomenological potentials between the alpha and LAMBDA particles. We obtained two bound states for J suppi = 1/2 sup + and 3/2 sup + , and three resonance states of (3/2) sub 1 sup - , (3/2) sub 2 sup - , (3/2) sub 3 sup -. We studied the properties of these states by calculating the components and the expectation values of the potential for each partial wave. It is found that a few channels dominate in the 1/2 sup + and 3/2 sup + states, so that the alpha-clusters or the sup 8 Be core are still alive in the nucleus. In a case were the two alpha particles are fixed on an axis the contour plots of the distribution of the LAMBDA particle are shown. With the assistence of these plots one can visually understand that some of them are shell-model-like states while others ...

Mathematic model analysis of Gaussian beam propagation through an arbitrary thickness random phase screen.

Science.gov (United States)

Tian, Yuzhen; Guo, Jin; Wang, Rui; Wang, Tingfeng

2011-09-12

In order to research the statistical properties of Gaussian beam propagation through an arbitrary thickness random phase screen for adaptive optics and laser communication application in the laboratory, we establish mathematic models of statistical quantities, which are based on the Rytov method and the thin phase screen model, involved in the propagation process. And the analytic results are developed for an arbitrary thickness phase screen based on the Kolmogorov power spectrum. The comparison between the arbitrary thickness phase screen and the thin phase screen shows that it is more suitable for our results to describe the generalized case, especially the scintillation index.

Investigation of. epsilon. sub 1 and the sup 3 P sub J phase shifts in the n-p system by the measurement of polarization transfer coefficients in p-d elastic scattering

Energy Technology Data Exchange (ETDEWEB)

Clajus, M.; Egun, P.M.; Grueebler, W.; Hautle, P. (Eidgenoessische Technische Hochschule, Zurich (Switzerland). Inst. fuer Mittelenergiephysik); Kretschmer, W.; Rauscher, A.; Schuster, W.; Weidmann, R.; Haller, M. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Physikalisches Inst.); Bruno, M.; Cannata, F.; D' Agostino, M. (Istituto Nazionale di Fisica Nucleare, Bologna (Italy) Bologna Univ. (Italy). Dipt. di Fisica); Slaus, I. (Institut Rudjer Boskovic, Zagreb (Yugoslavia)); Schmelzbach, P.A. (Paul Scherrer Inst., Villigen (Switzerland)); Vuaridel, B. (Michigan Univ., Ann Arbor (USA)); Sperisen, F. (Indiana Univ., Bloomington (USA). Cyclotron Facility); Witala, H.; Cornelius, T.; Gloeckle, W. (Bochum Univ. (Germany, F.R.))

1990-02-01

The {sup 3}S{sub 1}-{sup 3}D{sub 1} mixing parameter {epsilon}{sub 1} and the {sup 3}P{sub J} phase shifts in the N-N system at low energy are investigated in the three nucleon system. The sensitivity of polarization transfer coefficients in p-d elastic scattering is determined by rigorous Faddeev calculations using Paris and Bonn potentials. The experimental results of K{sub y}sup(y') favours the tensor force component of the Bonn A potential. (orig.).

Global mean-field phase diagram of the spin-1 Ising ferromagnet in a random crystal field

Science.gov (United States)

Borelli, M. E. S.; Carneiro, C. E. I.

1996-02-01

We study the phase diagram of the mean-field spin-1 Ising ferromagnet in a uniform magnetic field H and a random crystal field Δi, with probability distribution P( Δi) = pδ( Δi - Δ) + (1 - p) δ( Δi). We analyse the effects of randomness on the first-order surfaces of the Δ- T- H phase diagram for different values of the concentration p and show how these surfaces are affected by the dilution of the crystal field.

Efficient Text Encryption and Hiding with Double-Random Phase-Encoding

Directory of Open Access Journals (Sweden)

Mohammad S. Alam

2012-10-01

Full Text Available In this paper, a double-random phase-encoding technique-based text encryption and hiding method is proposed. First, the secret text is transformed into a 2-dimensional array and the higher bits of the elements in the transformed array are used to store the bit stream of the secret text, while the lower bits are filled with specific values. Then, the transformed array is encoded with double-random phase-encoding technique. Finally, the encoded array is superimposed on an expanded host image to obtain the image embedded with hidden data. The performance of the proposed technique, including the hiding capacity, the recovery accuracy of the secret text, and the quality of the image embedded with hidden data, is tested via analytical modeling and test data stream. Experimental results show that the secret text can be recovered either accurately or almost accurately, while maintaining the quality of the host image embedded with hidden data by properly selecting the method of transforming the secret text into an array and the superimposition coefficient. By using optical information processing techniques, the proposed method has been found to significantly improve the security of text information transmission, while ensuring hiding capacity at a prescribed level.

Ga-doped indium oxide nanowire phase change random access memory cells

International Nuclear Information System (INIS)

Jin, Bo; Lee, Jeong-Soo; Lim, Taekyung; Ju, Sanghyun; Latypov, Marat I; Kim, Hyoung Seop; Meyyappan, M

2014-01-01

Phase change random access memory (PCRAM) devices are usually constructed using tellurium based compounds, but efforts to seek other materials providing desirable memory characteristics have continued. We have fabricated PCRAM devices using Ga-doped In 2 O 3 nanowires with three different Ga compositions (Ga/(In+Ga) atomic ratio: 2.1%, 11.5% and 13.0%), and investigated their phase switching properties. The nanowires (∼40 nm in diameter) can be repeatedly switched between crystalline and amorphous phases, and Ga concentration-dependent memory switching behavior in the nanowires was observed with ultra-fast set/reset rates of 80 ns/20 ns, which are faster than for other competitive phase change materials. The observations of fast set/reset rates and two distinct states with a difference in resistance of two to three orders of magnitude appear promising for nonvolatile information storage. Moreover, we found that increasing the Ga concentration can reduce the power consumption and resistance drift; however, too high a level of Ga doping may cause difficulty in achieving the phase transition. (paper)

Relativistic quasiparticle random phase approximation in deformed nuclei

Energy Technology Data Exchange (ETDEWEB)

Pena Arteaga, D.

2007-06-25

Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogolyubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of the Goldstone modes. This allows the microscopic investigation of Pygmy and scissor resonances in electric and magnetic dipole fields. Excellent agreement with recent experiments is found and new types of modes are predicted for deformed systems with large neutron excess. (orig.)

Photons in dense nuclear matter: Random-phase approximation

Science.gov (United States)

Stetina, Stephan; Rrapaj, Ermal; Reddy, Sanjay

2018-04-01

We present a comprehensive and pedagogic discussion of the properties of photons in cold and dense nuclear matter based on the resummed one-loop photon self-energy. Correlations among electrons, muons, protons, and neutrons in β equilibrium that arise as a result of electromagnetic and strong interactions are consistently taken into account within the random phase approximation. Screening effects, damping, and collective excitations are systematically studied in a fully relativistic setup. Our study is relevant to the linear response theory of dense nuclear matter, calculations of transport properties of cold dense matter, and investigations of the production and propagation of hypothetical vector bosons such as the dark photons.

Calculations of recombination rates for cold 4He atoms from atom-dimer phase shifts and determination of universal scaling functions

International Nuclear Information System (INIS)

Shepard, J. R.

2007-01-01

Three-body recombination rates for cold 4 He are calculated with a method which exploits the simple relationship between the imaginary part of the atom-dimer elastic scattering phase shift and the S-matrix for recombination. The elastic phase shifts are computed above breakup threshold by solving a three-body Faddeev equation in momentum space with inputs based on a variety of modern atom-atom potentials. Recombination coefficients for the HFD-B3-FCII potential agree very well with the only previously published results. Since the elastic scattering and recombination processes for 4 He are governed by 'Efimov physics', they depend on universal functions of a scaling variable. The computed recombination coefficients for potentials other than HFD-B3-FCII make it possible to determine these universal functions

Arbitrary-step randomly delayed robust filter with application to boost phase tracking

Science.gov (United States)

Qin, Wutao; Wang, Xiaogang; Bai, Yuliang; Cui, Naigang

2018-04-01

The conventional filters such as extended Kalman filter, unscented Kalman filter and cubature Kalman filter assume that the measurement is available in real-time and the measurement noise is Gaussian white noise. But in practice, both two assumptions are invalid. To solve this problem, a novel algorithm is proposed by taking the following four steps. At first, the measurement model is modified by the Bernoulli random variables to describe the random delay. Then, the expression of predicted measurement and covariance are reformulated, which could get rid of the restriction that the maximum number of delay must be one or two and the assumption that probabilities of Bernoulli random variables taking the value one are equal. Next, the arbitrary-step randomly delayed high-degree cubature Kalman filter is derived based on the 5th-degree spherical-radial rule and the reformulated expressions. Finally, the arbitrary-step randomly delayed high-degree cubature Kalman filter is modified to the arbitrary-step randomly delayed high-degree cubature Huber-based filter based on the Huber technique, which is essentially an M-estimator. Therefore, the proposed filter is not only robust to the randomly delayed measurements, but robust to the glint noise. The application to the boost phase tracking example demonstrate the superiority of the proposed algorithms.

Excitations and phase transitions in random anti-ferromagnets

International Nuclear Information System (INIS)

Cowley, R.A.; Birgeneau, R.J.; Shirane, G.

1979-01-01

Neutron scattering techniques can be used to study the magnetic excitations and phase transitions in the randomly mixed transition metal fluorides. The results for the excitations of samples with two different types of magnetic ions show two bands of excitations; each associated with excitations propagating largely on one type of ion. In the diluted salts the spectra show a complex line shape and greater widths. These results are in good accord with computer simulations showing that linear spin wave theory can be used, but have not been described satisfactorily using the coherent potential approximation. The phase transitions in these materials are always smeared, but it is difficult to ascertain if this smearing is due to macroscopic fluctuations in the concentration or of an intrinsic origin. Studies of these systems close to the percolation point have shown that the thermal disorder is associated with the one-dimensional weak links of the large clusters. Currently theory and experiment are in accord for the two-dimensional Ising system but features are still not understood in Heisenberg systems in both two and three dimensions

Laser-beam apodization with a graded random phase window

Energy Technology Data Exchange (ETDEWEB)

Haas, R.A.; Summers, M.A.; Linford, G.J.

1986-10-01

Experiments and analysis indicate that graded random phase modulation can be usesd to apodize a laser beam. In the case of an obscuration or a hard edge it can prevent the formation of Fresnel-diffraction ripples. For example, here the interaction of a 1-..mu..m-wavelength laser beam with a central obscuration of half-width a -- 100 ..mu..m is studied theoretically. It is found that if the exit surface of a window, placed immediately downstream of the obstacle, is randomly modulated with a Gaussian amplitude transverse correlation length l -- 50..mu..m and a mean-square amplitude that decreases exponentially from a peak height of --1..mu..m/sup 2/ away from the center of the obscuration with transverse scale length L -- 500 ..mu..m, then the Fresenel-diffraction ripples normally produced by the obscuration are elimated. The scaling of these results is also discussed. The calculations are in general agreement with experimental results.

Laser-beam apodization with a graded random phase window

International Nuclear Information System (INIS)

Haas, R.A.; Summers, M.A.; Linford, G.J.

1986-01-01

Experiments and analysis indicate that graded random phase modulation can be usesd to apodize a laser beam. In the case of an obscuration or a hard edge it can prevent the formation of Fresnel-diffraction ripples. For example, here the interaction of a 1-μm-wavelength laser beam with a central obscuration of half-width a -- 100 μm is studied theoretically. It is found that if the exit surface of a window, placed immediately downstream of the obstacle, is randomly modulated with a Gaussian amplitude transverse correlation length l -- 50μm and a mean-square amplitude that decreases exponentially from a peak height of --1μm 2 away from the center of the obscuration with transverse scale length L -- 500 μm, then the Fresenel-diffraction ripples normally produced by the obscuration are elimated. The scaling of these results is also discussed. The calculations are in general agreement with experimental results

Disorder Induced Dynamic Equilibrium Localization and Random Phase Steps of Bose—Einstein Condensates

International Nuclear Information System (INIS)

Duan Ya-Fan; Xu Zhen; Qian Jun; Sun Jian-Fang; Jiang Bo-Nan; Hong Tao

2011-01-01

We numerically analyze the dynamic behavior of Bose—Einstein condensate (BEC) in a one-dimensional disordered potential before it completely loses spatial quantum coherence. We find that both the disorder statistics and the atom interactions produce remarkable effects on localization. We also find that the single phase of the initial condensate is broken into many small pieces while the system approaches localization, showing a counter-intuitive step-wise phase but not a thoroughly randomized phase. Although the condensates as a whole show less flow and expansion, the currents between adjacent phase steps retain strong time dependence. Thus we show explicitly that the localization of a finite size Bose—Einstein condensate is a dynamic equilibrium state. (general)

The generation of 68 Gbps quantum random number by measuring laser phase fluctuations

International Nuclear Information System (INIS)

Nie, You-Qi; Liu, Yang; Zhang, Jun; Pan, Jian-Wei; Huang, Leilei; Payne, Frank

2015-01-01

The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage

A random walk rule for phase I clinical trials.

Science.gov (United States)

Durham, S D; Flournoy, N; Rosenberger, W F

1997-06-01

We describe a family of random walk rules for the sequential allocation of dose levels to patients in a dose-response study, or phase I clinical trial. Patients are sequentially assigned the next higher, same, or next lower dose level according to some probability distribution, which may be determined by ethical considerations as well as the patient's response. It is shown that one can choose these probabilities in order to center dose level assignments unimodally around any target quantile of interest. Estimation of the quantile is discussed; the maximum likelihood estimator and its variance are derived under a two-parameter logistic distribution, and the maximum likelihood estimator is compared with other nonparametric estimators. Random walk rules have clear advantages: they are simple to implement, and finite and asymptotic distribution theory is completely worked out. For a specific random walk rule, we compute finite and asymptotic properties and give examples of its use in planning studies. Having the finite distribution theory available and tractable obviates the need for elaborate simulation studies to analyze the properties of the design. The small sample properties of our rule, as determined by exact theory, compare favorably to those of the continual reassessment method, determined by simulation.

Key management of the double random-phase-encoding method using public-key encryption

Science.gov (United States)

Saini, Nirmala; Sinha, Aloka

2010-03-01

Public-key encryption has been used to encode the key of the encryption process. In the proposed technique, an input image has been encrypted by using the double random-phase-encoding method using extended fractional Fourier transform. The key of the encryption process have been encoded by using the Rivest-Shamir-Adelman (RSA) public-key encryption algorithm. The encoded key has then been transmitted to the receiver side along with the encrypted image. In the decryption process, first the encoded key has been decrypted using the secret key and then the encrypted image has been decrypted by using the retrieved key parameters. The proposed technique has advantage over double random-phase-encoding method because the problem associated with the transmission of the key has been eliminated by using public-key encryption. Computer simulation has been carried out to validate the proposed technique.

Encoding plaintext by Fourier transform hologram in double random phase encoding using fingerprint keys

Science.gov (United States)

Takeda, Masafumi; Nakano, Kazuya; Suzuki, Hiroyuki; Yamaguchi, Masahiro

2012-09-01

It has been shown that biometric information can be used as a cipher key for binary data encryption by applying double random phase encoding. In such methods, binary data are encoded in a bit pattern image, and the decrypted image becomes a plain image when the key is genuine; otherwise, decrypted images become random images. In some cases, images decrypted by imposters may not be fully random, such that the blurred bit pattern can be partially observed. In this paper, we propose a novel bit coding method based on a Fourier transform hologram, which makes images decrypted by imposters more random. Computer experiments confirm that the method increases the randomness of images decrypted by imposters while keeping the false rejection rate as low as in the conventional method.

Encoding plaintext by Fourier transform hologram in double random phase encoding using fingerprint keys

International Nuclear Information System (INIS)

Takeda, Masafumi; Nakano, Kazuya; Suzuki, Hiroyuki; Yamaguchi, Masahiro

2012-01-01

It has been shown that biometric information can be used as a cipher key for binary data encryption by applying double random phase encoding. In such methods, binary data are encoded in a bit pattern image, and the decrypted image becomes a plain image when the key is genuine; otherwise, decrypted images become random images. In some cases, images decrypted by imposters may not be fully random, such that the blurred bit pattern can be partially observed. In this paper, we propose a novel bit coding method based on a Fourier transform hologram, which makes images decrypted by imposters more random. Computer experiments confirm that the method increases the randomness of images decrypted by imposters while keeping the false rejection rate as low as in the conventional method. (paper)

Double random phase spread spectrum spread space technique for secure parallel optical multiplexing with individual encryption key

Science.gov (United States)

Hennelly, B. M.; Javidi, B.; Sheridan, J. T.

2005-09-01

A number of methods have been recently proposed in the literature for the encryption of 2-D information using linear optical systems. In particular the double random phase encoding system has received widespread attention. This system uses two Random Phase Keys (RPK) positioned in the input spatial domain and the spatial frequency domain and if these random phases are described by statistically independent white noises then the encrypted image can be shown to be a white noise. Decryption only requires knowledge of the RPK in the frequency domain. The RPK may be implemented using a Spatial Light Modulators (SLM). In this paper we propose and investigate the use of SLMs for secure optical multiplexing. We show that in this case it is possible to encrypt multiple images in parallel and multiplex them for transmission or storage. The signal energy is effectively spread in the spatial frequency domain. As expected the number of images that can be multiplexed together and recovered without loss is proportional to the ratio of the input image and the SLM resolution. Many more images may be multiplexed with some loss in recovery. Furthermore each individual encryption is more robust than traditional double random phase encoding since decryption requires knowledge of both RPK and a lowpass filter in order to despread the spectrum and decrypt the image. Numerical simulations are presented and discussed.

Deep Learning the Quantum Phase Transitions in Random Electron Systems: Applications to Three Dimensions

Science.gov (United States)

Ohtsuki, Tomi; Ohtsuki, Tomoki

2017-04-01

Three-dimensional random electron systems undergo quantum phase transitions and show rich phase diagrams. Examples of the phases are the band gap insulator, Anderson insulator, strong and weak topological insulators, Weyl semimetal, and diffusive metal. As in the previous paper on two-dimensional quantum phase transitions [J. Phys. Soc. Jpn. 85, 123706 (2016)], we use an image recognition algorithm based on a multilayered convolutional neural network to identify which phase the eigenfunction belongs to. The Anderson model for localization-delocalization transition, the Wilson-Dirac model for topological insulators, and the layered Chern insulator model for Weyl semimetal are studied. The situation where the standard transfer matrix approach is not applicable is also treated by this method.

Choice of optical system is critical for the security of double random phase encryption systems

Science.gov (United States)

Muniraj, Inbarasan; Guo, Changliang; Malallah, Ra'ed; Cassidy, Derek; Zhao, Liang; Ryle, James P.; Healy, John J.; Sheridan, John T.

2017-06-01

The linear canonical transform (LCT) is used in modeling a coherent light-field propagation through first-order optical systems. Recently, a generic optical system, known as the quadratic phase encoding system (QPES), for encrypting a two-dimensional image has been reported. In such systems, two random phase keys and the individual LCT parameters (α,β,γ) serve as secret keys of the cryptosystem. It is important that such encryption systems also satisfy some dynamic security properties. We, therefore, examine such systems using two cryptographic evaluation methods, the avalanche effect and bit independence criterion, which indicate the degree of security of the cryptographic algorithms using QPES. We compared our simulation results with the conventional Fourier and the Fresnel transform-based double random phase encryption (DRPE) systems. The results show that the LCT-based DRPE has an excellent avalanche and bit independence characteristics compared to the conventional Fourier and Fresnel-based encryption systems.

Random phase approximation: from Giant to Intra-doublet resonances

International Nuclear Information System (INIS)

Amusia, M.Ya.

2004-01-01

We discuss here the history and current achievements of one of the most powerful approaches of 20th century physics--the random phase approximation (RPA) that permits us to study collective or multiparticle effects in atoms, nuclei, molecules and clusters, as well as in quantum liquids. We concentrate on RPA application to studies of isolated atoms where it permits one to disclose the collective multielectron nature of so-called Giant resonances and predict a number of others, like Interference and Intra-doublet resonances. We present general theory as well as results of concrete calculations for a number of atoms

Random phase approximation: from Giant to Intra-doublet resonances

Energy Technology Data Exchange (ETDEWEB)

Amusia, M.Ya. E-mail: amusia@vms.huji.ac.il

2004-06-01

We discuss here the history and current achievements of one of the most powerful approaches of 20th century physics--the random phase approximation (RPA) that permits us to study collective or multiparticle effects in atoms, nuclei, molecules and clusters, as well as in quantum liquids. We concentrate on RPA application to studies of isolated atoms where it permits one to disclose the collective multielectron nature of so-called Giant resonances and predict a number of others, like Interference and Intra-doublet resonances. We present general theory as well as results of concrete calculations for a number of atoms.

Random signal tomographical analysis of two-phase flow

International Nuclear Information System (INIS)

Han, P.; Wesser, U.

1990-01-01

This paper reports on radiation tomography which is a useful tool for studying the internal structures of two-phase flow. However, general tomography analysis gives only time-averaged results, hence much information is lost. As a result, it is sometimes difficult to identify the flow regime; for example, the time-averaged picture does not significantly change as an annual flow develops from a slug flow. A two-phase flow diagnostic technique based on random signal tomographical analysis is developed. It extracts more information by studying the statistical variation of the measured signal with time. Local statistical parameters, including mean value, variance, skewness and flatness etc., are reconstructed from the information obtained by a general tomography technique. More important information are provided by the results. Not only the void fraction can be easily calculated, but also the flow pattern can be identified more objectively and more accurately. The experimental setup is introduced. It consisted of a two-phase flow loop, an X-ray system, a fan-like five-beam detector system and a signal acquisition and processing system. In the experiment, for both horizontal and vertical test sections (aluminum and steel tube with Di/Do = 40/45 mm), different flow situations are realized by independently adjusting air and water mass flow. Through a glass tube connected with the test section, some typical flow patterns are visualized and used for comparing with the reconstruction results

A novel attack method about double-random-phase-encoding-based image hiding method

Science.gov (United States)

Xu, Hongsheng; Xiao, Zhijun; Zhu, Xianchen

2018-03-01

By using optical image processing techniques, a novel text encryption and hiding method applied by double-random phase-encoding technique is proposed in the paper. The first step is that the secret message is transformed into a 2-dimension array. The higher bits of the elements in the array are used to fill with the bit stream of the secret text, while the lower bits are stored specific values. Then, the transformed array is encoded by double random phase encoding technique. Last, the encoded array is embedded on a public host image to obtain the image embedded with hidden text. The performance of the proposed technique is tested via analytical modeling and test data stream. Experimental results show that the secret text can be recovered either accurately or almost accurately, while maintaining the quality of the host image embedded with hidden data by properly selecting the method of transforming the secret text into an array and the superimposition coefficient.

First-order corrections to random-phase approximation GW calculations in silicon and diamond

NARCIS (Netherlands)

Ummels, R.T.M.; Bobbert, P.A.; van Haeringen, W.

1998-01-01

We report on ab initio calculations of the first-order corrections in the screened interaction W to the random-phase approximation polarizability and to the GW self-energy, using a noninteracting Green's function, for silicon and diamond. It is found that the first-order vertex and self-consistency

Impulse attack-free four random phase mask encryption based on a 4-f optical system.

Science.gov (United States)

Kumar, Pramod; Joseph, Joby; Singh, Kehar

2009-04-20

Optical encryption methods based on double random phase encryption (DRPE) have been shown to be vulnerable to different types of attacks. The Fourier plane random phase mask (RPM), which is the most important key, can be cracked with a single impulse function attack. Such an attack is viable because the Fourier transform of a delta function is a unity function. Formation of a unity function can be avoided if RPMs are placed in front of both lenses in a 4-f optical setup, thereby protecting the DRPE from an impulse attack. We have performed numerical simulations to verify the proposed scheme. Resistance of this scheme is checked against the brute force and the impulse function attacks. The experimental results validate the feasibility of the scheme.

Information hiding based on double random-phase encoding and public-key cryptography.

Science.gov (United States)

Sheng, Yuan; Xin, Zhou; Alam, Mohammed S; Xi, Lu; Xiao-Feng, Li

2009-03-02

A novel information hiding method based on double random-phase encoding (DRPE) and Rivest-Shamir-Adleman (RSA) public-key cryptosystem is proposed. In the proposed technique, the inherent diffusion property of DRPE is cleverly utilized to make up the diffusion insufficiency of RSA public-key cryptography, while the RSA cryptosystem is utilized for simultaneous transmission of the cipher text and the two phase-masks, which is not possible under the DRPE technique. This technique combines the complementary advantages of the DPRE and RSA encryption techniques and brings security and convenience for efficient information transmission. Extensive numerical simulation results are presented to verify the performance of the proposed technique.

Isoscalar compression modes in relativistic random phase approximation

International Nuclear Information System (INIS)

Ma, Zhong-yu; Van Giai, Nguyen.; Wandelt, A.; Vretenar, D.; Ring, P.

2001-01-01

Monopole and dipole compression modes in nuclei are analyzed in the framework of a fully consistent relativistic random phase approximation (RRPA), based on effective mean-field Lagrangians with nonlinear meson self-interaction terms. The large effect of Dirac sea states on isoscalar strength distribution functions is illustrated for the monopole mode. The main contribution of Fermi and Dirac sea pair states arises through the exchange of the scalar meson. The effect of vector meson exchange is much smaller. For the monopole mode, RRPA results are compared with constrained relativistic mean-field calculations. A comparison between experimental and calculated energies of isoscalar giant monopole resonances points to a value of 250-270 MeV for the nuclear matter incompressibility. A large discrepancy remains between theoretical predictions and experimental data for the dipole compression mode

Accelerated three-dimensional cine phase contrast imaging using randomly undersampled echo planar imaging with compressed sensing reconstruction.

Science.gov (United States)

Basha, Tamer A; Akçakaya, Mehmet; Goddu, Beth; Berg, Sophie; Nezafat, Reza

2015-01-01

The aim of this study was to implement and evaluate an accelerated three-dimensional (3D) cine phase contrast MRI sequence by combining a randomly sampled 3D k-space acquisition sequence with an echo planar imaging (EPI) readout. An accelerated 3D cine phase contrast MRI sequence was implemented by combining EPI readout with randomly undersampled 3D k-space data suitable for compressed sensing (CS) reconstruction. The undersampled data were then reconstructed using low-dimensional structural self-learning and thresholding (LOST). 3D phase contrast MRI was acquired in 11 healthy adults using an overall acceleration of 7 (EPI factor of 3 and CS rate of 3). For comparison, a single two-dimensional (2D) cine phase contrast scan was also performed with sensitivity encoding (SENSE) rate 2 and approximately at the level of the pulmonary artery bifurcation. The stroke volume and mean velocity in both the ascending and descending aorta were measured and compared between two sequences using Bland-Altman plots. An average scan time of 3 min and 30 s, corresponding to an acceleration rate of 7, was achieved for 3D cine phase contrast scan with one direction flow encoding, voxel size of 2 × 2 × 3 mm(3) , foot-head coverage of 6 cm and temporal resolution of 30 ms. The mean velocity and stroke volume in both the ascending and descending aorta were statistically equivalent between the proposed 3D sequence and the standard 2D cine phase contrast sequence. The combination of EPI with a randomly undersampled 3D k-space sampling sequence using LOST reconstruction allows a seven-fold reduction in scan time of 3D cine phase contrast MRI without compromising blood flow quantification. Copyright © 2014 John Wiley & Sons, Ltd.

Configuration space Faddeev calculations

International Nuclear Information System (INIS)

Payne, G.L.; Klink, W.H.; Polyzou, W.N.

1989-01-01

The detailed study of few-body systems provides one of the most effective means for studying nuclear physics at subnucleon distance scales. For few-body systems the model equations can be solved numerically with errors less than the experimental uncertainties. We have used such systems to investigate the size of relativistic effects, the role of meson-exchange currents, and the importance of quark degrees of freedom in the nucleus. Complete calculations for momentum-dependent potentials have been performed, and the properties of the three-body bound state for these potentials have been studied. Few-body calculations of the electromagnetic form factors of the deuteron and pion have been carried out using a front-form formulation of relativistic quantum mechanics. The decomposition of the operators transforming convariantly under the Poincare group into kinematical and dynamical parts has been studies. New ways for constructing interactions between particles, as well as interactions which lead to the production of particles, have been constructed in the context of a relativistic quantum mechanics. To compute scattering amplitudes in a nonperturbative way, classes of operators have been generated out of which the phase operator may be constructed. Finally, we have worked out procedures for computing Clebsch-Gordan and Racah coefficients on a computer, as well as giving procedures for dealing with the multiplicity problem

Dynamical replica analysis of processes on finitely connected random graphs: II. Dynamics in the Griffiths phase of the diluted Ising ferromagnet

International Nuclear Information System (INIS)

Mozeika, A; Coolen, A C C

2009-01-01

We study the Glauber dynamics of Ising spin models with random bonds, on finitely connected random graphs. We generalize a recent dynamical replica theory with which to predict the evolution of the joint spin-field distribution, to include random graphs with arbitrary degree distributions. The theory is applied to Ising ferromagnets on randomly diluted Bethe lattices, where we study the evolution of the magnetization and the internal energy. It predicts a prominent slowing down of the flow in the Griffiths phase, it suggests a further dynamical transition at lower temperatures within the Griffiths phase, and it is verified quantitatively by the results of Monte Carlo simulations

Modified random phase approximation for multipole excitations at finite temperature

International Nuclear Information System (INIS)

Nguyen Dinh Dang

1991-01-01

The modified finite temperature random phase approximation (modified FT-RPA) has been constructed with taking the influence of thermostat on the structure of quansiparticles into account. The modified FT-RPA linear response for electric quadrupole (λ π = 2 + ) and octupole (λ π = 3 - ) excitations in 5 8Ni has been calculated as a function of the nuclear temperature. As compared to the conventional FT-RPA the modified FT-RPA has given a stronger spreading for the strength distribution of quandrupole excitations at finite temperature T ≤ 3MeV. (author). 22 refs; 4 figs; 2 tabs

Calculating beta decay in the deformed self-consistent quasiparticle random phase approximation

Energy Technology Data Exchange (ETDEWEB)

Engel, Jonathan, E-mail: engelj@physics.unc.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Mustonen, M. T., E-mail: mika.mustonen@yale.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06052 (United States)

2016-06-21

We discuss a recent global calculation of beta-decay rates in the self-consistent Skyrme quasiparticle random phase approximation (QRPA), with axially symmetric nuclear deformation treated explicitly. The calculation makes makes use of the finite-amplitude method, first proposed by Nakatsukasa and collaborators, to reduce computation time. The results are comparable in quality to those of several other global QRPA calculations. The QRPA may have reached the limit of its accuracy.

Neutrino-nucleus reaction rates based on the relativistic quasiparticle random phase approximation

International Nuclear Information System (INIS)

Paar, N.; Vretenar, D.; Marketin, T.; Ring, P.

2008-01-01

Neutrino-nucleus cross sections are described in a novel theoretical framework where the weak interaction of leptons with hadrons is expressed in the standard current-current form, the nuclear ground state is described in the relativistic Hartree-Bogoliubov model, and the relevant transitions to excited states are calculated in the relativistic quasiparticle random phase approximation. The model is employed in studies of neutrino-nucleus reactions in several test cases

A random phased array device for delivery of high intensity focused ultrasound.

Science.gov (United States)

Hand, J W; Shaw, A; Sadhoo, N; Rajagopal, S; Dickinson, R J; Gavrilov, L R

2009-10-07

Randomized phased arrays can offer electronic steering of a single focus and simultaneous multiple foci concomitant with low levels of secondary maxima and are potentially useful as sources of high intensity focused ultrasound (HIFU). This work describes laboratory testing of a 1 MHz random phased array consisting of 254 elements on a spherical shell of radius of curvature 130 mm and diameter 170 mm. Acoustic output power and efficiency are measured for a range of input electrical powers, and field distributions for various single- and multiple-focus conditions are evaluated by a novel technique using an infrared camera to provide rapid imaging of temperature changes on the surface of an absorbing target. Experimental results show that the array can steer a single focus laterally to at least +/-15 mm off axis and axially to more than +/-15 mm from the centre of curvature of the array and patterns of four and five simultaneous foci +/-10 mm laterally and axially whilst maintaining low intensity levels in secondary maxima away from the targeted area in good agreement with linear theoretical predictions. Experiments in which pork meat was thermally ablated indicate that contiguous lesions several cm(3) in volume can be produced using the patterns of multiple foci.

A random phased array device for delivery of high intensity focused ultrasound

International Nuclear Information System (INIS)

Hand, J W; Shaw, A; Sadhoo, N; Rajagopal, S; Dickinson, R J; Gavrilov, L R

2009-01-01

Randomized phased arrays can offer electronic steering of a single focus and simultaneous multiple foci concomitant with low levels of secondary maxima and are potentially useful as sources of high intensity focused ultrasound (HIFU). This work describes laboratory testing of a 1 MHz random phased array consisting of 254 elements on a spherical shell of radius of curvature 130 mm and diameter 170 mm. Acoustic output power and efficiency are measured for a range of input electrical powers, and field distributions for various single- and multiple-focus conditions are evaluated by a novel technique using an infrared camera to provide rapid imaging of temperature changes on the surface of an absorbing target. Experimental results show that the array can steer a single focus laterally to at least ±15 mm off axis and axially to more than ±15 mm from the centre of curvature of the array and patterns of four and five simultaneous foci ±10 mm laterally and axially whilst maintaining low intensity levels in secondary maxima away from the targeted area in good agreement with linear theoretical predictions. Experiments in which pork meat was thermally ablated indicate that contiguous lesions several cm 3 in volume can be produced using the patterns of multiple foci.

Phase Diagram in a Random Mixture of Two Antiferromagnets with Competing Spin Anisotropies. I

Science.gov (United States)

Someya, Yoshiko

1981-12-01

The phase diagram of a random mixture of two antiferromagnets with competing spin anisotropies (A1-xBx) has been analyzed by extending the theory of Matsubara and Inawashiro, and Oguchi and Ishikawa. In the model assumed, the anisotropy energies are expressed by the anisotropic exchange interactions. According to this formulation, it has been shown that the concentration dependence of TN becomes a function of \\includegraphics{dummy.eps}, where P, Q=A, B; SP is a magnitude of P-spin, and JPQη is a η component of exchange integral between P- and Q-spin). Further, the phase boundary between an AF phase and an OAF (oblique antiferromagnetic) phase at T{=}0 K has been shown to be determined by α({\\equiv}SB/SA), if \\includegraphics{dummy.eps} are given. The obtained phase diagrams for Fe1-xCoxCl2, K2Mn1-xFexF4 and Fe1-xCoxCl2\\cdot2H2O are compared with the experimental ones.

Optimized random phase approximation for the structure of liquid alkali metals as electron-ion plasmas

International Nuclear Information System (INIS)

Senatore, G.; Tosi, M.P.; Trieste Univ.

1981-08-01

The purpose of this letter is to stress that the way towards an unconventional optimized-random-phase-approximation (ORPA) approach to the structure of liquid metals is indicated, and in fact already a good first-order solution for such an approach is provided

Reconstruction of photon number conditioned states using phase randomized homodyne measurements

International Nuclear Information System (INIS)

Chrzanowski, H M; Assad, S M; Bernu, J; Hage, B; Lam, P K; Symul, T; Lund, A P; Ralph, T C

2013-01-01

We experimentally demonstrate the reconstruction of a photon number conditioned state without using a photon number discriminating detector. By using only phase randomized homodyne measurements, we reconstruct up to the three photon subtracted squeezed vacuum state. The reconstructed Wigner functions of these states show regions of pronounced negativity, signifying the non-classical nature of the reconstructed states. The techniques presented allow for complete characterization of the role of a conditional measurement on an ensemble of states, and might prove useful in systems where photon counting still proves technically challenging. (paper)

Extended random-phase approximation with three-body ground-state correlations

International Nuclear Information System (INIS)

Tohyama, M.; Schuck, P.

2008-01-01

An extended random-phase approximation (ERPA) which contains the effects of ground-state correlations up to a three-body level is applied to an extended Lipkin model which contains an additional particle-scattering term. Three-body correlations in the ground state are necessary to preserve the hermiticity of the Hamiltonian matrix of ERPA. Two approximate forms of ERPA which neglect the three-body correlations are also applied to investigate the importance of three-body correlations. It is found that the ground-state energy is little affected by the inclusion of the three-body correlations. On the contrary, three-body correlations for the excited states can become quite important. (orig.)

The impact of luteal phase support on endometrial estrogen and progesterone receptor expression: a randomized control trial

Directory of Open Access Journals (Sweden)

Brezina Paul R

2012-02-01

Full Text Available Abstract Background To assess the impact of luteal phase support on the expression of estrogen receptor (ER alpha and progesterone receptors B (PR-B on the endometrium of oocyte donors undergoing controlled ovarian hyperstimulation (COH. Methods A prospective, randomized study was conducted in women undergoing controlled ovarian hyperstimulation for oocyte donation. Participants were randomized to receive no luteal support, vaginal progesterone alone, or vaginal progesterone plus orally administered 17 Beta estradiol. Endometrial biopsies were obtained at 4 time points in the luteal phase and evaluated by tissue microarray for expression of ER alpha and PR-B. Results One-hundred and eight endometrial tissue samples were obtained from 12 patients. No differences were found in expression of ER alpha and PR-B among all the specimens with the exception of one sample value. Conclusions The administration of progesterone during the luteal phase of COH for oocyte donor cycles, either with or without estrogen, does not significantly affect the endometrial expression of ER alpha and PR.

Efficacy of extended-release tramadol for treatment of prescription opioid withdrawal: A two-phase randomized controlled trial*

Science.gov (United States)

Lofwall, Michelle R.; Babalonis, Shanna; Nuzzo, Paul A.; Siegel, Anthony; Campbell, Charles; Walsh, Sharon L.

2013-01-01

Background Tramadol is an atypical analgesic with monoamine and modest mu opioid agonist activity. The purpose of this study was to evaluate: 1) the efficacy of extended-release (ER) tramadol in treating prescription opioid withdrawal and 2) whether cessation of ER tramadol produces opioid withdrawal. Methods Prescription opioid users with current opioid dependence and observed withdrawal participated in this inpatient, two-phase double blind, randomized placebo-controlled trial. In Phase 1 (days 1-7), participants were randomly assigned to matched oral placebo or ER tramadol (200 or 600 mg daily). In Phase 2 (days 8-13), all participants underwent double blind crossover to placebo. Breakthrough withdrawal medications were available for all subjects. Enrollment continued until 12 completers/group was achieved. Results Use of breakthrough withdrawal medication differed significantly (popioid withdrawal. Mild opioid withdrawal occurred after cessation of treatment with 600 mg tramadol. These data support the continued investigation of tramadol as a treatment for opioid withdrawal. PMID:23755929

Efficacy of extended-release tramadol for treatment of prescription opioid withdrawal: a two-phase randomized controlled trial.

Science.gov (United States)

Lofwall, Michelle R; Babalonis, Shanna; Nuzzo, Paul A; Siegel, Anthony; Campbell, Charles; Walsh, Sharon L

2013-11-01

Tramadol is an atypical analgesic with monoamine and modest mu opioid agonist activity. The purpose of this study was to evaluate: (1) the efficacy of extended-release (ER) tramadol in treating prescription opioid withdrawal and (2) whether cessation of ER tramadol produces opioid withdrawal. Prescription opioid users with current opioid dependence and observed withdrawal participated in this inpatient, two-phase double blind, randomized placebo-controlled trial. In Phase 1 (days 1-7), participants were randomly assigned to matched oral placebo or ER tramadol (200 or 600 mg daily). In Phase 2 (days 8-13), all participants underwent double blind crossover to placebo. Breakthrough withdrawal medications were available for all subjects. Enrollment continued until 12 completers/group was achieved. Use of breakthrough withdrawal medication differed significantly (popioid withdrawal. Mild opioid withdrawal occurred after cessation of treatment with 600 mg tramadol. These data support the continued investigation of tramadol as a treatment for opioid withdrawal. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A randomized phase II dose-response exercise trial among colon cancer survivors: Purpose, study design, methods, and recruitment results.

Science.gov (United States)

Brown, Justin C; Troxel, Andrea B; Ky, Bonnie; Damjanov, Nevena; Zemel, Babette S; Rickels, Michael R; Rhim, Andrew D; Rustgi, Anil K; Courneya, Kerry S; Schmitz, Kathryn H

2016-03-01

Observational studies indicate that higher volumes of physical activity are associated with improved disease outcomes among colon cancer survivors. The aim of this report is to describe the purpose, study design, methods, and recruitment results of the courage trial, a National Cancer Institute (NCI) sponsored, phase II, randomized, dose-response exercise trial among colon cancer survivors. The primary objective of the courage trial is to quantify the feasibility, safety, and physiologic effects of low-dose (150 min·week(-1)) and high-dose (300 min·week(-1)) moderate-intensity aerobic exercise compared to usual-care control group over six months. The exercise groups are provided with in-home treadmills and heart rate monitors. Between January and July 2015, 1433 letters were mailed using a population-based state cancer registry; 126 colon cancer survivors inquired about participation, and 39 were randomized onto the study protocol. Age was associated with inquiry about study participation (Pclinical, or geographic characteristics were associated with study inquiry or randomization. The final trial participant was randomized in August 2015. Six month endpoint data collection was completed in February 2016. The recruitment of colon cancer survivors into an exercise trial is feasible. The findings from this trial will inform key design aspects for future phase 2 and phase 3 randomized controlled trials to examine the efficacy of exercise to improve clinical outcomes among colon cancer survivors. Copyright © 2016 Elsevier Inc. All rights reserved.

Phase diagrams of a spin-1/2 transverse Ising model with three-peak random field distribution

International Nuclear Information System (INIS)

Bassir, A.; Bassir, C.E.; Benyoussef, A.; Ez-Zahraouy, H.

1996-07-01

The effect of the transverse magnetic field on the phase diagrams structures of the Ising model in a random longitudinal magnetic field with a trimodal symmetric distribution is investigated within a finite cluster approximation. We find that a small magnetizations ordered phase (small ordered phase) disappears completely for a sufficiently large value of the transverse field or/and large value of the concentration of the disorder of the magnetic field. Multicritical behaviour and reentrant phenomena are discussed. The regions where the tricritical, reentrant phenomena and the small ordered phase persist are delimited as a function of the transverse field and the concentration p. Longitudinal magnetizations are also presented. (author). 33 refs, 6 figs

Random projections and the optimization of an algorithm for phase retrieval

International Nuclear Information System (INIS)

Elser, Veit

2003-01-01

Iterative phase retrieval algorithms typically employ projections onto constraint subspaces to recover the unknown phases in the Fourier transform of an image, or, in the case of x-ray crystallography, the electron density of a molecule. For a general class of algorithms, where the basic iteration is specified by the difference map, solutions are associated with fixed points of the map, the attractive character of which determines the effectiveness of the algorithm. The behaviour of the difference map near fixed points is controlled by the relative orientation of the tangent spaces of the two constraint subspaces employed by the map. Since the dimensionalities involved are always large in practical applications, it is appropriate to use random matrix theory ideas to analyse the average-case convergence at fixed points. Optimal values of the γ parameters of the difference map are found which differ somewhat from the values previously obtained on the assumption of orthogonal tangent spaces

Quantum mechanics of the fractional-statistics gas: Random-phase approximation

International Nuclear Information System (INIS)

Dai, Q.; Levy, J.L.; Fetter, A.L.; Hanna, C.B.; Laughlin, R.B.

1992-01-01

A description of the fractional-statistics gas based on the complete summation of Hartree, Fock, ladder and bubble diagrams is presented. The superfluid properties identified previously in the random-phase-approximation (RPA) calculation of Fetter, Hanna, and Laughlin [Phys. Rev. B 39, 9679 (1989)] are substantially confirmed. The discrepancy between the RPA sound speed and the Hartree-Fock bulk modulus is found to be eliminated. The unusual Hall-effect behavior is found to vanish for the Bose gas test case but not for the fractional-statistics gas, implying that it is physically correct. Excellent agreement is obtained with the collective-mode dispersion obtained numerically by Xie, He, and Das Sarma [Phys. Rev. Lett. 65, 649 (1990)

Finite-temperature random-phase approximation for spectroscopic properties of neon plasmas

International Nuclear Information System (INIS)

Colgan, J.; Collins, L. A.; Fontes, C. J.; Csanak, G.

2007-01-01

A finite-temperature random-phase approximation (FTRPA) is applied to calculate oscillator strengths for excitations in hot and dense plasmas. Application of the FTRPA provides a convenient, self-consistent method with which to explore coupled-channel effects of excited electrons in a dense plasma. We present FTRPA calculations that include coupled-channel effects. The inclusion of these effects is shown to cause significant differences in the oscillator strength for a prototypical case of 1 P excitation in neon when compared with single-channel and with average-atom calculations. Trends as a function of temperature and density are also discussed

Statistical properties of laser hot spots produced by a random phase plate

International Nuclear Information System (INIS)

Rose, H.A.; DuBois, D.F.

1993-01-01

A quantitative theory of laser hot spots, which control plasma instabilities in real laser--plasma interactions, is presented in the case of random phase plate (RPP) optics. It is shown that the probability density of intense hot spots with intensity I, P hot (I), is given by P hot (I)∼(I/I 0 2 )exp(-I/I 0 ) where I 0 is the average intensity, and that the detailed amplitude and phase variation of the laser field in the vicinity of an intense hot spot is uniquely specified by the optics and is deterministic. These hot spots may be the source of below threshold stimulated Raman scattering (SRS) and its variation with I 0 is shown to be super exponential. A brief preview of a quantitative nonlinear theory of hot-spot-induced laser filamentation is presented

SPIRIT: A seamless phase I/II randomized design for immunotherapy trials.

Science.gov (United States)

Guo, Beibei; Li, Daniel; Yuan, Ying

2018-06-07

Immunotherapy-treatments that enlist the immune system to battle tumors-has received widespread attention in cancer research. Due to its unique features and mechanisms for treating cancer, immunotherapy requires novel clinical trial designs. We propose a Bayesian seamless phase I/II randomized design for immunotherapy trials (SPIRIT) to find the optimal biological dose (OBD) defined in terms of the restricted mean survival time. We jointly model progression-free survival and the immune response. Progression-free survival is used as the primary endpoint to determine the OBD, and the immune response is used as an ancillary endpoint to quickly screen out futile doses. Toxicity is monitored throughout the trial. The design consists of two seamlessly connected stages. The first stage identifies a set of safe doses. The second stage adaptively randomizes patients to the safe doses identified and uses their progression-free survival and immune response to find the OBD. The simulation study shows that the SPIRIT has desirable operating characteristics and outperforms the conventional design. Copyright © 2018 John Wiley & Sons, Ltd.

Dietary Soy Supplement on Fibromyalgia Symptoms: A Randomized, Double-Blind, Placebo-Controlled, Early Phase Trial

Science.gov (United States)

Wahner-Roedler, Dietlind L.; Thompson, Jeffrey M.; Luedtke, Connie A.; King, Susan M.; Cha, Stephen S.; Elkin, Peter L.; Bruce, Barbara K.; Townsend, Cynthia O.; Bergeson, Jody R.; Eickhoff, Andrea L.; Loehrer, Laura L.; Sood, Amit; Bauer, Brent A.

2011-01-01

Most patients with fibromyalgia use complementary and alternative medicine (CAM). Properly designed controlled trials are necessary to assess the effectiveness of these practices. This study was a randomized, double-blind, placebo-controlled, early phase trial. Fifty patients seen at a fibromyalgia outpatient treatment program were randomly assigned to a daily soy or placebo (casein) shake. Outcome measures were scores of the Fibromyalgia Impact Questionnaire (FIQ) and the Center for Epidemiologic Studies Depression Scale (CES-D) at baseline and after 6 weeks of intervention. Analysis was with standard statistics based on the null hypothesis, and separation test for early phase CAM comparative trials. Twenty-eight patients completed the study. Use of standard statistics with intent-to-treat analysis showed that total FIQ scores decreased by 14% in the soy group (P = .02) and by 18% in the placebo group (P fibromyalgia treatment program, provide a decrease in fibromyalgia symptoms. Separation between the effects of soy and casein (control) shakes did not favor the intervention. Therefore, large-sample studies using soy for patients with fibromyalgia are probably not indicated. PMID:18990724

Experimental phase diagram for random laser spectra

International Nuclear Information System (INIS)

El-Dardiry, Ramy G S; Mooiweer, Ronald; Lagendijk, Ad

2012-01-01

We systematically study the presence of narrow spectral features in a wide variety of random laser samples. Less gain or stronger scattering are shown to lead to a crossover from spiky to smooth spectra. A decomposition of random laser spectra into a set of Lorentzians provides unprecedented detail in the analysis of random laser spectra. We suggest an interpretation in terms of mode competition that enables an understanding of the observed experimental trends. In this interpretation, smooth random laser spectra are a consequence of competing modes for which the loss and gain are proportional. Spectral spikes are associated with modes that are uncoupled from the mode competition in the bulk of the sample. (paper)

Scandium doping brings speed improvement in Sb2Te alloy for phase change random access memory application.

Science.gov (United States)

Chen, Xin; Zheng, Yonghui; Zhu, Min; Ren, Kun; Wang, Yong; Li, Tao; Liu, Guangyu; Guo, Tianqi; Wu, Lei; Liu, Xianqiang; Cheng, Yan; Song, Zhitang

2018-05-01

Phase change random access memory (PCRAM) has gained much attention as a candidate for nonvolatile memory application. To develop PCRAM materials with better properties, especially to draw closer to dynamic random access memory (DRAM), the key challenge is to research new high-speed phase change materials. Here, Scandium (Sc) has been found it is helpful to get high-speed and good stability after doping in Sb 2 Te alloy. Sc 0.1 Sb 2 Te based PCRAM cell can achieve reversible switching by applying even 6 ns voltage pulse experimentally. And, Sc doping not only promotes amorphous stability but also improves the endurance ability comparing with pure Sb 2 Te alloy. Moreover, according to DFT calculations, strong Sc-Te bonds lead to the rigidity of Sc centered octahedrons, which may act as crystallization precursors in recrystallization process to boost the set speed.

Key-space analysis of double random phase encryption technique

Science.gov (United States)

Monaghan, David S.; Gopinathan, Unnikrishnan; Naughton, Thomas J.; Sheridan, John T.

2007-09-01

We perform a numerical analysis on the double random phase encryption/decryption technique. The key-space of an encryption technique is the set of possible keys that can be used to encode data using that technique. In the case of a strong encryption scheme, many keys must be tried in any brute-force attack on that technique. Traditionally, designers of optical image encryption systems demonstrate only how a small number of arbitrary keys cannot decrypt a chosen encrypted image in their system. However, this type of demonstration does not discuss the properties of the key-space nor refute the feasibility of an efficient brute-force attack. To clarify these issues we present a key-space analysis of the technique. For a range of problem instances we plot the distribution of decryption errors in the key-space indicating the lack of feasibility of a simple brute-force attack.

Role of an encapsulating layer for reducing resistance drift in phase change random access memory

Directory of Open Access Journals (Sweden)

Bo Jin

2014-12-01

Full Text Available Phase change random access memory (PCRAM devices exhibit a steady increase in resistance in the amorphous phase upon aging and this resistance drift phenomenon directly affects the device reliability. A stress relaxation model is used here to study the effect of a device encapsulating layer material in addressing the resistance drift phenomenon in PCRAM. The resistance drift can be increased or decreased depending on the biaxial moduli of the phase change material (YPCM and the encapsulating layer material (YELM according to the stress relationship between them in the drift regime. The proposed model suggests that the resistance drift can be effectively reduced by selecting a proper material as an encapsulating layer. Moreover, our model explains that reducing the size of the phase change material (PCM while fully reset and reducing the amorphous/crystalline ratio in PCM help to improve the resistance drift, and thus opens an avenue for highly reliable multilevel PCRAM applications.

A Multispectral Photon-Counting Double Random Phase Encoding Scheme for Image Authentication

Directory of Open Access Journals (Sweden)

Faliu Yi

2014-05-01

Full Text Available In this paper, we propose a new method for color image-based authentication that combines multispectral photon-counting imaging (MPCI and double random phase encoding (DRPE schemes. The sparsely distributed information from MPCI and the stationary white noise signal from DRPE make intruder attacks difficult. In this authentication method, the original multispectral RGB color image is down-sampled into a Bayer image. The three types of color samples (red, green and blue color in the Bayer image are encrypted with DRPE and the amplitude part of the resulting image is photon counted. The corresponding phase information that has nonzero amplitude after photon counting is then kept for decryption. Experimental results show that the retrieved images from the proposed method do not visually resemble their original counterparts. Nevertheless, the original color image can be efficiently verified with statistical nonlinear correlations. Our experimental results also show that different interpolation algorithms applied to Bayer images result in different verification effects for multispectral RGB color images.

A multispectral photon-counting double random phase encoding scheme for image authentication.

Science.gov (United States)

Yi, Faliu; Moon, Inkyu; Lee, Yeon H

2014-05-20

In this paper, we propose a new method for color image-based authentication that combines multispectral photon-counting imaging (MPCI) and double random phase encoding (DRPE) schemes. The sparsely distributed information from MPCI and the stationary white noise signal from DRPE make intruder attacks difficult. In this authentication method, the original multispectral RGB color image is down-sampled into a Bayer image. The three types of color samples (red, green and blue color) in the Bayer image are encrypted with DRPE and the amplitude part of the resulting image is photon counted. The corresponding phase information that has nonzero amplitude after photon counting is then kept for decryption. Experimental results show that the retrieved images from the proposed method do not visually resemble their original counterparts. Nevertheless, the original color image can be efficiently verified with statistical nonlinear correlations. Our experimental results also show that different interpolation algorithms applied to Bayer images result in different verification effects for multispectral RGB color images.

Separable pairing force for relativistic quasiparticle random-phase approximation

International Nuclear Information System (INIS)

Tian Yuan; Ma Zhongyu; Ring, Peter

2009-01-01

We have introduced a separable pairing force, which was adjusted to reproduce the pairing properties of the Gogny force in nuclear matter. This separable pairing force is able to describe in relativistic Hartree-Bogoliubov (RHB) calculations the pairing properties in the ground state of finite nuclei on almost the same footing as the original Gogny interaction. In this work we investigate excited states using the Relativistic Quasiparticle Random-Phase Approximation (RQRPA) with the same separable pairing force. For consistency the Goldstone modes and the convergence with various cutoff parameters in this version of RQRPA are studied. The first excited 2 + states for the chain of Sn isotopes with Z=50 and the chain of isotones with N=82 isotones are calculated in RQRPA together with the 3 - states of Sn isotopes. By comparing our results with experimental data and with the results of the original Gogny force we find that this simple separable pairing interaction is very successful in depicting the pairing properties of vibrational excitations.

Anyonic FRT construction

International Nuclear Information System (INIS)

Majid, S.; Rodriguez-Plaza, M.J.

1994-01-01

The Faddeev-Reshetikhin-Takhtajan method to construct matrix bialgebras from non-singular solutions of the quantum Yang-Baxter equation is extended to the anyonic or Z n -graded case. The resulting anyonic quantum matrices are braided groups in which the braiding is given by a phase factor. (orig.)

Random excitation forces in tube bundles subjected to two-phase cross-flow

International Nuclear Information System (INIS)

Taylor, C.E.; Pettigrew, M.J.; Currie, I.G.

1996-01-01

Data from two experimental programs have been analyzed to determine the characteristics of the random excitation forces associated with two-phase cross-flow in tube bundles. Large-scale air-water flow loops in France and Canada were used to generate the data. Tests were carried out on cantilevered, clamped-pinned, and clamped-clamped tubes in normal-square, parallel-triangular, and normal-triangular configurations. Either strain gages or force transducers were used to measure the vibration response of a centrally located tube as the tue array was subjected to a wide range of void fractions and flow rates. Power spectra were analyzed to determine the effect of parameters such as tube diameter, frequency, flow rate, void fraction, and flow regime on the random excitation forces. Normalized expressions for the excitation force power spectra were found to be flow-regime dependent. In the churn flow regime, flow rate and void fraction had very little effect on the magnitude of the excitation forces. In the bubble-plug flow regime, the excitation forces increased rapidly with flow rate and void fraction

Random-phase approximation and its extension for the O(2) anharmonic oscillator

International Nuclear Information System (INIS)

Aouissat, Z.; Martin, C.

2004-01-01

We apply the random-phase approximation (RPA) and its extension called renormalized RPA to the quantum anharmonic oscillator with an O(2) symmetry. We first obtain the equation for the RPA frequencies in the standard and in the renormalized RPAs using the equation-of-motion method. In the case where the ground state has a broken symmetry, we check the existence of a zero frequency in the standard and in the renormalized RPAs. Then we use a time-dependent approach where the standard-RPA frequencies are obtained as small oscillations around the static solution in the time-dependent Hartree-Bogolyubov equation. We draw the parallel between the two approaches. (orig.)

Random-phase approximation and its extension for the O(2) anharmonic oscillator

Energy Technology Data Exchange (ETDEWEB)

Aouissat, Z. [Institut fuer Kernphysik, Technische Hochschule Darmstadt, Schlossgarten 9, D-64289, Darmstadt (Germany); Martin, C. [Groupe de Physique Theorique, Institut de Physique Nucleaire, F-91406, Orsay Cedex (France)

2004-02-01

We apply the random-phase approximation (RPA) and its extension called renormalized RPA to the quantum anharmonic oscillator with an O(2) symmetry. We first obtain the equation for the RPA frequencies in the standard and in the renormalized RPAs using the equation-of-motion method. In the case where the ground state has a broken symmetry, we check the existence of a zero frequency in the standard and in the renormalized RPAs. Then we use a time-dependent approach where the standard-RPA frequencies are obtained as small oscillations around the static solution in the time-dependent Hartree-Bogolyubov equation. We draw the parallel between the two approaches. (orig.)

Color image encryption using random transforms, phase retrieval, chaotic maps, and diffusion

Science.gov (United States)

Annaby, M. H.; Rushdi, M. A.; Nehary, E. A.

2018-04-01

The recent tremendous proliferation of color imaging applications has been accompanied by growing research in data encryption to secure color images against adversary attacks. While recent color image encryption techniques perform reasonably well, they still exhibit vulnerabilities and deficiencies in terms of statistical security measures due to image data redundancy and inherent weaknesses. This paper proposes two encryption algorithms that largely treat these deficiencies and boost the security strength through novel integration of the random fractional Fourier transforms, phase retrieval algorithms, as well as chaotic scrambling and diffusion. We show through detailed experiments and statistical analysis that the proposed enhancements significantly improve security measures and immunity to attacks.

Topical tofacitinib for atopic dermatitis: a phase IIa randomized trial.

Science.gov (United States)

Bissonnette, R; Papp, K A; Poulin, Y; Gooderham, M; Raman, M; Mallbris, L; Wang, C; Purohit, V; Mamolo, C; Papacharalambous, J; Ports, W C

2016-11-01

Despite unmet need, 15 years have passed since a topical therapy with a new mechanism of action for atopic dermatitis (AD) has been approved. Janus kinase (JAK) inhibitor treatment effect via topical application in patients with AD is unknown. Tofacitinib, a small-molecule JAK inhibitor, was investigated for the topical treatment of AD. In this 4-week, phase IIa, randomized, double-blind, vehicle-controlled study (NCT02001181), 69 adults with mild-to-moderate AD were randomized 1:1 to 2% tofacitinib or vehicle ointment twice daily. Percentage change from baseline (CFB) in Eczema Area and Severity Index (EASI) score at week 4 was the primary end point. Secondary efficacy end points included percentage CFB in body surface area (BSA), CFB in EASI Clinical Signs Severity Sum Score, proportion of patients with Physician's Global Assessment (PGA) response and CFB in patient-reported pruritus. Safety, local tolerability and pharmacokinetics were monitored. The mean percentage CFB at week 4 in EASI score was significantly greater (P tofacitinib (-81·7%) vs. vehicle (-29·9%). Patients treated with tofacitinib showed significant (P tofacitinib. Tofacitinib ointment showed significantly greater efficacy vs. vehicle across end points, with early onset of effect and comparable safety/local tolerability to vehicle. JAK inhibition through topical delivery is potentially a promising therapeutic target for AD. © 2016 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.

Communication: Random phase approximation renormalized many-body perturbation theory

International Nuclear Information System (INIS)

Bates, Jefferson E.; Furche, Filipp

2013-01-01

We derive a renormalized many-body perturbation theory (MBPT) starting from the random phase approximation (RPA). This RPA-renormalized perturbation theory extends the scope of single-reference MBPT methods to small-gap systems without significantly increasing the computational cost. The leading correction to RPA, termed the approximate exchange kernel (AXK), substantially improves upon RPA atomization energies and ionization potentials without affecting other properties such as barrier heights where RPA is already accurate. Thus, AXK is more balanced than second-order screened exchange [A. Grüneis et al., J. Chem. Phys. 131, 154115 (2009)], which tends to overcorrect RPA for systems with stronger static correlation. Similarly, AXK avoids the divergence of second-order Møller-Plesset (MP2) theory for small gap systems and delivers a much more consistent performance than MP2 across the periodic table at comparable cost. RPA+AXK thus is an accurate, non-empirical, and robust tool to assess and improve semi-local density functional theory for a wide range of systems previously inaccessible to first-principles electronic structure calculations

Multi-kW coherent combining of fiber lasers seeded with pseudo random phase modulated light

Science.gov (United States)

Flores, Angel; Ehrehreich, Thomas; Holten, Roger; Anderson, Brian; Dajani, Iyad

2016-03-01

We report efficient coherent beam combining of five kilowatt-class fiber amplifiers with a diffractive optical element (DOE). Based on a master oscillator power amplifier (MOPA) configuration, the amplifiers were seeded with pseudo random phase modulated light. Each non-polarization maintaining fiber amplifier was optically path length matched and provides approximately 1.2 kW of near diffraction-limited output power (measured M2polarization control. A low power sample of the combined beam after the DOE provided an error signal for active phase locking which was performed via Locking of Optical Coherence by Single-Detector Electronic-Frequency Tagging (LOCSET). After phase stabilization, the beams were coherently combined via the 1x5 DOE. A total combined output power of 4.9 kW was achieved with 82% combining efficiency and excellent beam quality (M2splitter loss was 5%. Similarly, losses due in part to non-ideal polarization, ASE content, uncorrelated wavefront errors, and misalignment errors contributed to the efficiency reduction.

Beyond the Random Phase Approximation for the Electron Correlation Energy: The Importance of Single Excitations

OpenAIRE

Ren, Xinguo; Rinke, Patrick; Tkatchenko, Alexandre; Scheffler, Matthias

2010-01-01

The random-phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange (EX) energy, represents the state-of-the-art exchange-correlation functional within density-functional theory. However, the standard RPA practice-evaluating both the EX and the RPA correlation energies using Kohn-Sham (KS) orbitals from local or semilocal exchange-correlation functionals-leads to a systematic underbinding of molecules and solids. Here we demonstrate that this behavior ca...

The Kubo-Greenwood formula as a result of the random phase approximation for the electrons of the metal

Science.gov (United States)

Ivliev, S. V.

2017-12-01

For calculation of short laser pulse absorption in metal the imaginary part of permittivity, which is simply related to the conductivity, is required. Currently to find the static and dynamic conductivity the Kubo-Greenwood formula is most commonly used. It describes the electromagnetic energy absorption in the one-electron approach. In the present study, this formula is derived directly from the expression for the permittivity expression in the random phase approximation, which in fact is equivalent to the method of the mean field. The detailed analysis of the role of electron-electron interaction in the calculation of the matrix elements of the velocity operator is given. It is shown that in the one-electron random phase approximation the single-particle conductive electron wave functions in the field of fixed ions should be used. The possibility of considering the exchange and correlation effects by means of an amendment to a local function field is discussed.

Defect-mediated relaxation in the random tiling phase of a binary mixture: Birth, death and mobility of an atomic zipper

Energy Technology Data Exchange (ETDEWEB)

Tondl, Elisabeth; Ramsay, Malcolm; Harrowell, Peter; Widmer-Cooper, Asaph [School of Chemistry, University of Sydney, Sydney, NSW 2006 (Australia)

2014-03-14

This paper describes the mechanism of defect-mediated relaxation in a dodecagonal square-triangle random tiling phase exhibited by a simulated binary mixture of soft discs in 2D. We examine the internal transitions within the elementary mobile defect (christened the “zipper”) that allow it to move, as well as the mechanisms by which the zipper is created and annihilated. The structural relaxation of the random tiling phase is quantified and we show that this relaxation is well described by a model based on the distribution of waiting times for each atom to be visited by the diffusing zipper. This system, representing one of the few instances where a well defined mobile defect is capable of structural relaxation, can provide a valuable test case for general theories of relaxation in complex and disordered materials.

Defect-mediated relaxation in the random tiling phase of a binary mixture: Birth, death and mobility of an atomic zipper

International Nuclear Information System (INIS)

Tondl, Elisabeth; Ramsay, Malcolm; Harrowell, Peter; Widmer-Cooper, Asaph

2014-01-01

This paper describes the mechanism of defect-mediated relaxation in a dodecagonal square-triangle random tiling phase exhibited by a simulated binary mixture of soft discs in 2D. We examine the internal transitions within the elementary mobile defect (christened the “zipper”) that allow it to move, as well as the mechanisms by which the zipper is created and annihilated. The structural relaxation of the random tiling phase is quantified and we show that this relaxation is well described by a model based on the distribution of waiting times for each atom to be visited by the diffusing zipper. This system, representing one of the few instances where a well defined mobile defect is capable of structural relaxation, can provide a valuable test case for general theories of relaxation in complex and disordered materials

Dispersive and Covalent Interactions between Graphene and Metal Surfaces from the Random Phase Approximation

DEFF Research Database (Denmark)

Olsen, Thomas; Yan, Jun; Mortensen, Jens Jørgen

2011-01-01

We calculate the potential energy surfaces for graphene adsorbed on Cu(111), Ni(111), and Co(0001) using density functional theory and the random phase approximation (RPA). For these adsorption systems covalent and dispersive interactions are equally important and while commonly used approximations...... for exchange-correlation functionals give inadequate descriptions of either van der Waals or chemical bonds, RPA accounts accurately for both. It is found that the adsorption is a delicate competition between a weak chemisorption minimum close to the surface and a physisorption minimum further from the surface....

Shaping the spectrum of random-phase radar waveforms

Science.gov (United States)

Doerry, Armin W.; Marquette, Brandeis

2017-05-09

The various technologies presented herein relate to generation of a desired waveform profile in the form of a spectrum of apparently random noise (e.g., white noise or colored noise), but with precise spectral characteristics. Hence, a waveform profile that could be readily determined (e.g., by a spoofing system) is effectively obscured. Obscuration is achieved by dividing the waveform into a series of chips, each with an assigned frequency, wherein the sequence of chips are subsequently randomized. Randomization can be a function of the application of a key to the chip sequence. During processing of the echo pulse, a copy of the randomized transmitted pulse is recovered or regenerated against which the received echo is correlated. Hence, with the echo energy range-compressed in this manner, it is possible to generate a radar image with precise impulse response.

Quasi-Coherent Noise Jamming to LFM Radar Based on Pseudo-random Sequence Phase-modulation

Directory of Open Access Journals (Sweden)

N. Tai

2015-12-01

Full Text Available A novel quasi-coherent noise jamming method is proposed against linear frequency modulation (LFM signal and pulse compression radar. Based on the structure of digital radio frequency memory (DRFM, the jamming signal is acquired by the pseudo-random sequence phase-modulation of sampled radar signal. The characteristic of jamming signal in time domain and frequency domain is analyzed in detail. Results of ambiguity function indicate that the blanket jamming effect along the range direction will be formed when jamming signal passes through the matched filter. By flexible controlling the parameters of interrupted-sampling pulse and pseudo-random sequence, different covering distances and jamming effects will be achieved. When the jamming power is equivalent, this jamming obtains higher process gain compared with non-coherent jamming. The jamming signal enhances the detection threshold and the real target avoids being detected. Simulation results and circuit engineering implementation validate that the jamming signal covers real target effectively.

Hubbard-U corrected Hamiltonians for non-self-consistent random-phase approximation total-energy calculations

DEFF Research Database (Denmark)

Patrick, Christopher; Thygesen, Kristian Sommer

2016-01-01

In non-self-consistent calculations of the total energy within the random-phase approximation (RPA) for electronic correlation, it is necessary to choose a single-particle Hamiltonian whose solutions are used to construct the electronic density and noninteracting response function. Here we...... investigate the effect of including a Hubbard-U term in this single-particle Hamiltonian, to better describe the on-site correlation of 3d electrons in the transitionmetal compounds ZnS, TiO2, and NiO.We find that the RPA lattice constants are essentially independent of U, despite large changes...... in the underlying electronic structure. We further demonstrate that the non-selfconsistent RPA total energies of these materials have minima at nonzero U. Our RPA calculations find the rutile phase of TiO2 to be more stable than anatase independent of U, a result which is consistent with experiments...

Random phase approximation applied to solids, molecules, and graphene-metal interfaces

DEFF Research Database (Denmark)

Olsen, Thomas; Thygesen, Kristian S.

2013-01-01

The random phase approximation (RPA) is attracting renewed interest as a universal and accurate method for first-principles total energy calculations. The RPA naturally accounts for long-range dispersive forces without compromising accuracy for short-range interactions making the RPA superior...... to semilocal and hybrid functionals in systems dominated by weak van der Waals or mixed covalent-dispersive interactions. In this work, we present plane-wave-based RPA calculations for a broad collection of systems with bond types ranging from strong covalent to van der Waals. Our main result is the RPA...... the RPA captures both the weak covalent and dispersive forces, which are equally important for these systems. We benchmark our implementation in the GPAW electronic structure code by calculating cohesive energies of graphite and a range of covalently bonded solids and molecules as well as the dissociation...

Analysis of double random phase encryption from a key-space perspective

Science.gov (United States)

Monaghan, David S.; Situ, Guohai; Ryle, James; Gopinathan, Unnikrishnan; Naughton, Thomas J.; Sheridan, John T.

2007-09-01

The main advantage of the double random phase encryption technique is its physical implementation however to allow us to analyse its behaviour we perform the encryption/decryption numerically. A typically strong encryption scheme will have an extremely large key-space, which will make the probable success of any brute force attack on that algorithm miniscule. Traditionally, designers of optical image encryption systems only demonstrate how a small number of arbitrary keys cannot decrypt a chosen encrypted image in their system. We analyse this algorithm from a key-space perspective. The key-space of an encryption algorithm can be defined as the set of possible keys that can be used to encode data using that algorithm. For a range of problem instances we plot the distribution of decryption errors in the key-space indicating the lack of feasibility of a simple brute force attack.

Importance of self-consistency in relativistic continuum random-phase approximation calculations

International Nuclear Information System (INIS)

Yang Ding; Cao Ligang; Tian Yuan; Ma Zhongyu

2010-01-01

A fully consistent relativistic continuum random phase approximation (RCRPA) is constructed, where the contribution of the continuum spectrum to nuclear excitations is treated exactly by the single-particle Green's function technique. The full consistency of the calculations is achieved that the same effective Lagrangian is adopted for the ground state and the excited states. The negative energy states in the Dirac sea are also included in the single-particle Green's function in the no-sea approximation. The currents from the vector meson and photon exchanges and the Coulomb interaction in RCRPA are treated exactly. The spin-orbit interaction is included naturally in the relativistic frame. Numerical results of the RCRPA are checked with the constrained relativistic mean-field theory. We study the effects of the inconsistency, particularly the currents and Coulomb interaction in various collective multipole excitations.

Closed-form solution for the Wigner phase-space distribution function for diffuse reflection and small-angle scattering in a random medium.

Science.gov (United States)

Yura, H T; Thrane, L; Andersen, P E

2000-12-01

Within the paraxial approximation, a closed-form solution for the Wigner phase-space distribution function is derived for diffuse reflection and small-angle scattering in a random medium. This solution is based on the extended Huygens-Fresnel principle for the optical field, which is widely used in studies of wave propagation through random media. The results are general in that they apply to both an arbitrary small-angle volume scattering function, and arbitrary (real) ABCD optical systems. Furthermore, they are valid in both the single- and multiple-scattering regimes. Some general features of the Wigner phase-space distribution function are discussed, and analytic results are obtained for various types of scattering functions in the asymptotic limit s > 1, where s is the optical depth. In particular, explicit results are presented for optical coherence tomography (OCT) systems. On this basis, a novel way of creating OCT images based on measurements of the momentum width of the Wigner phase-space distribution is suggested, and the advantage over conventional OCT images is discussed. Because all previous published studies regarding the Wigner function are carried out in the transmission geometry, it is important to note that the extended Huygens-Fresnel principle and the ABCD matrix formalism may be used successfully to describe this geometry (within the paraxial approximation). Therefore for completeness we present in an appendix the general closed-form solution for the Wigner phase-space distribution function in ABCD paraxial optical systems for direct propagation through random media, and in a second appendix absorption effects are included.

Local Treatment of Unresectable Colorectal Liver Metastases: Results of a Randomized Phase II Trial.

Science.gov (United States)

Ruers, Theo; Van Coevorden, Frits; Punt, Cornelis J A; Pierie, Jean-Pierre E N; Borel-Rinkes, Inne; Ledermann, Jonathan A; Poston, Graeme; Bechstein, Wolf; Lentz, Marie-Ange; Mauer, Murielle; Folprecht, Gunnar; Van Cutsem, Eric; Ducreux, Michel; Nordlinger, Bernard

2017-09-01

Tumor ablation is often employed for unresectable colorectal liver metastases. However, no survival benefit has ever been demonstrated in prospective randomized studies. Here, we investigate the long-term benefits of such an aggressive approach. In this randomized phase II trial, 119 patients with unresectable colorectal liver metastases (n  38%) was met. We now report on long-term OS results. All statistical tests were two-sided. The analyses were according to intention to treat. At a median follow up of 9.7 years, 92 of 119 (77.3%) patients had died: 39 of 60 (65.0%) in the combined modality arm and 53 of 59 (89.8%) in the systemic treatment arm. Almost all patients died of progressive disease (35 patients in the combined modality arm, 49 patients in the systemic treatment arm). There was a statistically significant difference in OS in favor of the combined modality arm (hazard ratio [HR] = 0.58, 95% confidence interval [CI] = 0.38 to 0.88, P = .01). Three-, five-, and eight-year OS were 56.9% (95% CI = 43.3% to 68.5%), 43.1% (95% CI = 30.3% to 55.3%), 35.9% (95% CI = 23.8% to 48.2%), respectively, in the combined modality arm and 55.2% (95% CI = 41.6% to 66.9%), 30.3% (95% CI = 19.0% to 42.4%), 8.9% (95% CI = 3.3% to 18.1%), respectively, in the systemic treatment arm. Median OS was 45.6 months (95% CI = 30.3 to 67.8 months) in the combined modality arm vs 40.5 months (95% CI = 27.5 to 47.7 months) in the systemic treatment arm. This phase II trial is the first randomized study demonstrating that aggressive local treatment can prolong OS in patients with unresectable colorectal liver metastases. © The Author 2017. Published by Oxford University Press.

Improved light extraction from white organic light-emitting devices using a binary random phase array

International Nuclear Information System (INIS)

Inada, Yasuhisa; Nishiwaki, Seiji; Hirasawa, Taku; Nakamura, Yoshitaka; Hashiya, Akira; Wakabayashi, Shin-ichi; Suzuki, Masa-aki; Matsuzaki, Jumpei

2014-01-01

We have developed a binary random phase array (BRPA) to improve the light extraction performance of white organic light-emitting devices (WOLEDs). We demonstrated that the scattering of incoming light can be controlled by employing diffraction optics to modify the structural parameters of the BRPA. Applying a BRPA to the substrate of the WOLED leads to enhanced extraction efficiency and suppression of angle-dependent color changes. Our systematic study clarifies the effect of scattering on the light extraction of WOLEDs

Improved light extraction from white organic light-emitting devices using a binary random phase array

Energy Technology Data Exchange (ETDEWEB)

Inada, Yasuhisa, E-mail: inada.yasuhisa@jp.panasonic.com; Nishiwaki, Seiji; Hirasawa, Taku; Nakamura, Yoshitaka; Hashiya, Akira; Wakabayashi, Shin-ichi; Suzuki, Masa-aki [R and D Division, Panasonic Corporation, 1006 Kadoma, Kadoma City, Osaka 571-8501 (Japan); Matsuzaki, Jumpei [Device Development Center, Eco Solutions Company, Panasonic Corporation, 1048 Kadoma, Osaka 571-8686 Japan (Japan)

2014-02-10

We have developed a binary random phase array (BRPA) to improve the light extraction performance of white organic light-emitting devices (WOLEDs). We demonstrated that the scattering of incoming light can be controlled by employing diffraction optics to modify the structural parameters of the BRPA. Applying a BRPA to the substrate of the WOLED leads to enhanced extraction efficiency and suppression of angle-dependent color changes. Our systematic study clarifies the effect of scattering on the light extraction of WOLEDs.

Coherent-phase or random-phase acceleration of electron beams in solar flares

Science.gov (United States)

Aschwanden, Markus J.; Benz, Arnold O.; Montello, Maria L.

1994-01-01

Time structures of electron beam signatures at radio wavelengths are investigated to probe correlated versus random behavior in solar flares. In particular we address the issue whether acceleration and injection of electron beams is coherently modulated by a single source, or whether the injection is driven by a stochastic (possibly spatially fragmented) process. We analyze a total of approximately = 6000 type III bursts observed by Ikarus (Zurich) in the frequency range of 100-500 MHz, during 359 solar flares with simultaneous greater than or = 25 keV hard X-ray emission, in the years 1890-1983. In 155 flares we find a total of 260 continuous type III groups, with an average number of 13 +/- 9 bursts per group, a mean duration of D = 12 +/- 14 s, a mean period of P = 2.0 +/- 1.2 s, with the highest burst rate at a frequency of nu = 310 +/- 120 MHz. Pulse periods have been measured between 0.5 and 10 s, and can be described by an exponential distribution, i.e., N(P) varies as e (exp -P/1.0s). The period shows a frequency dependence of P(nu)=46(exp-0.6)(sub MHz)s for different flares, but is invariant during a particular flare. We measure the mean period P and its standard deviation sigma (sub p) in each type III group, and quantify the degree of periodicity (or phase-coherence) by the dimensionless parameter sigma (sub p)P. The representative sample of 260 type III burst groups shows a mean periodicity of sigma (sub p/P) = 0.37 +/- 0.12, while Monte Carlo simulations of an equivalent set of truly random time series show a distinctly different value of sigma (sub p)P = 0.93 +/- 0.26. This result indicates that the injection of electron beams is coherently modulated by a particle acceleration source which is either compact or has a global organization on a timescale of seconds, in contrast to an incoherent acceleration source, which is stochastic either in time or space. We discuss the constraints on the size of the acceleration region resulting from electron beam

Random magnetism

International Nuclear Information System (INIS)

Tsallis, C.

1980-03-01

The 'ingredients' which control a phase transition in well defined system as well as in random ones (e.g. random magnetic systems) are listed and discussed within a somehow unifying perspective. Among these 'ingredients' we find the couplings and elements responsible for the cooperative phenomenon, the topological connectivity as well as possible topological incompatibilities, the influence of new degrees of freedom, the order parameter dimensionality, the ground state degeneracy and finally the 'quanticity' of the system. The general trends, though illustrated in magnetic systems, essentially hold for all phase transitions, and give a basis for connection of this area with Field theory, Theory of dynamical systems, etc. (Author) [pt

Random magnetism

International Nuclear Information System (INIS)

Tsallis, C.

1981-01-01

The 'ingredients' which control a phase transition in well defined systems as well as in random ones (e.q. random magnetic systems) are listed and discussed within a somehow unifying perspective. Among these 'ingredients' the couplings and elements responsible for the cooperative phenomenon, the topological connectivity as well as possible topological incompatibilities, the influence of new degrees of freedom, the order parameter dimensionality, the ground state degeneracy and finally the 'quanticity' of the system are found. The general trends, though illustrated in magnetic systems, essentially hold for all phase transitions, and give a basis for connection of this area with Field theory, Theory of dynamical systems, etc. (Author) [pt

Relativistic three-particle theory

International Nuclear Information System (INIS)

Hochauser, S.

1979-01-01

In keeping with recent developments in experimental nuclear physics, a formalism is developed to treat interactions between three relativistic nuclear particles. The concept of unitarity and a simple form of analyticity are used to construct coupled, integral, Faddeev-type equations and, with the help of analytic separable potentials, these are cast in simple, one-dimensional form. Energy-dependent potentials are introduced so as to take into account the sign-change of some phase shifts in the nucleon-nucleon interaction and parameters for these potentials are obtained. With regard to the success of such local potentials as the Yukawa potential, a recently developed method for expanding these in separable form is discussed. Finally, a new method for the numerical integration of the Faddeev equations along the real axis is introduced, thus avoiding the traditional need for contour rotations into the complex plane. (author)

The use of odd random phase electrochemical impedance spectroscopy to study lithium-based corrosion inhibition by active protective coatings

NARCIS (Netherlands)

Meeusen, M.; Visser, P.; Fernández Macía, L.; Hubin, A.; Terryn, H.A.; Mol, J.M.C.

2018-01-01

In this work, the study of the time-dependent behaviour of lithium carbonate based inhibitor technology for the active corrosion protection of aluminium alloy 2024-T3 is presented. Odd random phase electrochemical impedance spectroscopy (ORP-EIS) is selected as the electrochemical tool to study

Collapse of the random-phase approximation: Examples and counter-examples from the shell model

International Nuclear Information System (INIS)

Johnson, Calvin W.; Stetcu, Ionel

2009-01-01

The Hartree-Fock approximation to the many-fermion problem can break exact symmetries, and in some cases by changing a parameter in the interaction one can drive the Hartree-Fock minimum from a symmetry-breaking state to a symmetry-conserving state (also referred to as a 'phase transition' in the literature). The order of the transition is important when one applies the random-phase approximation (RPA) to the of the Hartree-Fock wave function: if first order, RPA is stable through the transition, but if second-order, then the RPA amplitudes become large and lead to unphysical results. The latter is known as 'collapse' of the RPA. While the difference between first- and second-order transitions in the RPA was first pointed out by Thouless, we present for the first time nontrivial examples of both first- and second-order transitions in a uniform model, the interacting shell-model, where we can compare to exact numerical results.

High energy X-ray phase and dark-field imaging using a random absorption mask.

Science.gov (United States)

Wang, Hongchang; Kashyap, Yogesh; Cai, Biao; Sawhney, Kawal

2016-07-28

High energy X-ray imaging has unique advantage over conventional X-ray imaging, since it enables higher penetration into materials with significantly reduced radiation damage. However, the absorption contrast in high energy region is considerably low due to the reduced X-ray absorption cross section for most materials. Even though the X-ray phase and dark-field imaging techniques can provide substantially increased contrast and complementary information, fabricating dedicated optics for high energies still remain a challenge. To address this issue, we present an alternative X-ray imaging approach to produce transmission, phase and scattering signals at high X-ray energies by using a random absorption mask. Importantly, in addition to the synchrotron radiation source, this approach has been demonstrated for practical imaging application with a laboratory-based microfocus X-ray source. This new imaging method could be potentially useful for studying thick samples or heavy materials for advanced research in materials science.

Correlated random-phase approximation from densities and in-medium matrix elements

Energy Technology Data Exchange (ETDEWEB)

Trippel, Richard; Roth, Robert [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany)

2016-07-01

The random-phase approximation (RPA) as well as the second RPA (SRPA) are established tools for the study of collective excitations in nuclei. Addressing the well known lack of correlations, we derived a universal framework for a fully correlated RPA based on the use of one- and two-body densities. We apply densities from coupled cluster theory and investigate the impact of correlations. As an alternative approach to correlations we use matrix elements transformed via in-medium similarity renormalization group (IM-SRG) in combination with RPA and SRPA. We find that within SRPA the use of IM-SRG matrix elements leads to the disappearance of instabilities of low-lying states. For the calculations we use normal-ordered two- plus three-body interactions derived from chiral effective field theory. We apply different Hamiltonians to a number of doubly-magic nuclei and calculate electric transition strengths.

Random phase approximations for the screening function in high Tc superconductors

International Nuclear Information System (INIS)

Lopez-Aguilar, F.; Costa-Quintana, J.; Sanchez, A.; Puig, T.; Aurell, M.T.; Martinez, L.M.; Munoz, J.S.

1990-01-01

This paper reports on the electronic transferences from the CuO 2 sheets toward the CuO 3 linear chain, which locate electrons in the orbitals p y /p z of O4/O1 and d z 2 -y 2 of Cu1, and holes in the orbitals d x 2 -y 2 - P z /p y of Cu2 - P2/O3. These holes states present large interatomic overlapping. In this paper, we determine the screening function within the random phase approximation applied to the high-T c superconductors. This screening function is vanishing for determined values of the frequency which correspond to renormalized plasmon frequencies. These frequencies depends on the band parameters and their knowledge is essential for determining the self energy. This self energy is deduced and it contain independent terms for each of the channels for the localization

Relativistic quasiparticle random-phase approximation calculation of total muon capture rates

International Nuclear Information System (INIS)

Marketin, T.; Paar, N.; Niksic, T.; Vretenar, D.

2009-01-01

The relativistic proton-neutron quasiparticle random phase approximation (pn-RQRPA) is applied in the calculation of total muon capture rates on a large set of nuclei from 12 C to 244 Pu, for which experimental values are available. The microscopic theoretical framework is based on the relativistic Hartree-Bogoliubov (RHB) model for the nuclear ground state, and transitions to excited states are calculated using the pn-RQRPA. The calculation is fully consistent, i.e., the same interactions are used both in the RHB equations that determine the quasiparticle basis, and in the matrix equations of the pn-RQRPA. The calculated capture rates are sensitive to the in-medium quenching of the axial-vector coupling constant. By reducing this constant from its free-nucleon value g A =1.262 by 10% for all multipole transitions, the calculation reproduces the experimental muon capture rates to better than 10% accuracy.

Generalization of Faddeev-Popov rules in Yang-Mills theories: N = 3,4 BRST symmetries

Science.gov (United States)

Reshetnyak, Alexander

2018-01-01

The Faddeev-Popov rules for a local and Poincaré-covariant Lagrangian quantization of a gauge theory with gauge group are generalized to the case of an invariance of the respective quantum actions, S(N), with respect to N-parametric Abelian SUSY transformations with odd-valued parameters λp, p = 1,…,N and generators sp: spsq + sqsp = 0, for N = 3, 4, implying the substitution of an N-plet of ghost fields, Cp, instead of the parameter, ξ, of infinitesimal gauge transformations: ξ = Cpλ p. The total configuration spaces of fields for a quantum theory of the same classical model coincide in the N = 3 and N = 4 symmetric cases. The superspace of N = 3 SUSY irreducible representation includes, in addition to Yang-Mills fields 𝒜μ, (3 + 1) ghost odd-valued fields Cp, B̂ and 3 even-valued Bpq for p, q = 1, 2, 3. To construct the quantum action, S(3), by adding to the classical action, S0(𝒜), of an N = 3-exact gauge-fixing term (with gauge fermion), a gauge-fixing procedure requires (1 + 3 + 3 + 1) additional fields, Φ¯(3): antighost C¯, 3 even-valued Bp, 3 odd-valued B̂pq and Nakanishi-Lautrup B fields. The action of N = 3 transformations on new fields as N = 3-irreducible representation space is realized. These transformations are the N = 3 BRST symmetry transformations for the vacuum functional, Z3(0) =∫dΦ(3)dΦ¯(3)exp{(ı/ℏ)S(3)}. The space of all fields (Φ(3),Φ¯(3)) proves to be the space of an irreducible representation of the fields Φ(4) for N = 4-parametric SUSY transformations, which contains, in addition to 𝒜μ the (4 + 6 + 4 + 1) ghost-antighost, Cr = (Cp,C¯), even-valued, Brs = -Bsr = (Bpq,Bp4 = Bp), odd-valued B̂r = (B̂,B̂pq) and B fields. The quantum action is constructed by adding to S0(𝒜) an N = 4-exact gauge-fixing term with a gauge boson, F(4). The N = 4 SUSY transformations are by N = 4 BRST transformations for the vacuum functional, Z4(0) =∫dΦ(4)exp{(ı/ℏ)S(4)}. The procedures are valid for

Relativistic quasiparticle random phase approximation with a separable pairing force

International Nuclear Information System (INIS)

Tian Yuan; Ma Zhongyu; Ring Peter

2009-01-01

In our previous work, we introduced a separable pairing force for relativistic Hartree-Bogoliubov calculations. This force was adjusted to reproduce the pairing properties of the Gogny force in nuclear matter. By using the well known techniques of Talmi and Moshinsky it can be expanded in a series of separable terms and converges quickly after a few terms. It was found that the pairing properties can be depicted on almost the same footing as the original pairing interaction, not only in nuclear matter, but also in finite nuclei. In this study, we construct a relativistic quasiparticle random phase approximation (RQRPA) with this separable pairing interaction and calculate the excitation energies of the first excited 2 + states and reduced B(E2; 0 + →2 + ) transition rates for a chain of Sn isotopes in RQRPA. Compared with the results of the full Gogny force, we find that this simple separable pairing interaction can describe the pairing properties of the excited vibrational states as well as the original pairing interaction. (authors)

Thermodynamics and structure of liquid metals from a consistent optimized random phase approximation

International Nuclear Information System (INIS)

Akinlade, O.; Badirkhan, Z.; Pastore, G.

2000-05-01

We study thermodynamics and structural properties of several liquid metals to assess the validity of the generalized non-local model potential (GNMP) of Li et. al. [J.Phys. F16,309 (1986)]. By using a new thermodynamically consistent version of the optimized random phase approximation (ORPA), especially adapted to continuous reference potentials, we improve our previous results obtained within the variational approach based on the Gibbs - Bogoliubov inequality. Hinging on the unified and very accurate evaluation of structure factors and thermodynamic quantities provided by the ORPA, we find that the GNMP yields satisfactory results for the alkali metals, however, those for the polyvalent metals point to a substantial inadequacy of the GNMP for high valence systems. (author)

Active control on high-order coherence and statistic characterization on random phase fluctuation of two classical point sources.

Science.gov (United States)

Hong, Peilong; Li, Liming; Liu, Jianji; Zhang, Guoquan

2016-03-29

Young's double-slit or two-beam interference is of fundamental importance to understand various interference effects, in which the stationary phase difference between two beams plays the key role in the first-order coherence. Different from the case of first-order coherence, in the high-order optical coherence the statistic behavior of the optical phase will play the key role. In this article, by employing a fundamental interfering configuration with two classical point sources, we showed that the high- order optical coherence between two classical point sources can be actively designed by controlling the statistic behavior of the relative phase difference between two point sources. Synchronous position Nth-order subwavelength interference with an effective wavelength of λ/M was demonstrated, in which λ is the wavelength of point sources and M is an integer not larger than N. Interestingly, we found that the synchronous position Nth-order interference fringe fingerprints the statistic trace of random phase fluctuation of two classical point sources, therefore, it provides an effective way to characterize the statistic properties of phase fluctuation for incoherent light sources.

The FINISH-3 Trial : A Phase 3, International, Randomized, Single-Blind, Controlled Trial of Topical Fibrocaps in Intraoperative Surgical Hemostasis

NARCIS (Netherlands)

Bochicchio, Grant V.; Gupta, Navyash; Porte, Robert J.; Renkens, Kenneth L.; Pattyn, Piet; Topal, Baki; Troisi, Roberto Ivan; Muir, William; Chetter, Ian; Gillen, Daniel L.; Zuckerman, Linda A.; Frohna, Paul A.

BACKGROUND: This Phase 3, international, randomized, single-blind, controlled trial (FINISH-3) compared the efficacy and safety of Fibrocaps, a ready-to-use, dry-powder fibrin sealant containing human plasma-derived thrombin and fibrinogen, vs gelatin sponge alone for use as a hemostat for surgical

Workshop on Strategic Behavior and Phase Transitions in Random and Complex Combinatorial Structures : Extended Abstracts

CERN Document Server

Kirousis, Lefteris; Ortiz-Gracia, Luis; Serna, Maria

2017-01-01

This book is divided into two parts, the first of which seeks to connect the phase transitions of various disciplines, including game theory, and to explore the synergies between statistical physics and combinatorics. Phase Transitions has been an active multidisciplinary field of research, bringing together physicists, computer scientists and mathematicians. The main research theme explores how atomic agents that act locally and microscopically lead to discontinuous macroscopic changes. Adopting this perspective has proven to be especially useful in studying the evolution of random and usually complex or large combinatorial objects (like networks or logic formulas) with respect to discontinuous changes in global parameters like connectivity, satisfiability etc. There is, of course, an obvious strategic element in the formation of a transition: the atomic agents “selfishly” seek to optimize a local parameter. However, up to now this game-theoretic aspect of abrupt, locally triggered changes had not been e...

Relativistic continuum random phase approximation in spherical nuclei

International Nuclear Information System (INIS)

Daoutidis, Ioannis

2009-01-01

Covariant density functional theory is used to analyze the nuclear response in the external multipole fields. The investigations are based on modern functionals with zero range and density dependent coupling constants. After a self-consistent solution of the Relativistic Mean Field (RMF) equations for the nuclear ground states multipole giant resonances are studied within the Relativistic Random Phase Approximation (RRPA), the small amplitude limit of the time-dependent RMF. The coupling to the continuum is treated precisely by calculating the single particle Greens-function of the corresponding Dirac equation. In conventional methods based on a discretization of the continuum this was not possible. The residual interaction is derived from the same RMF Lagrangian. This guarantees current conservation and a precise decoupling of the Goldstone modes. For nuclei with open shells pairing correlations are taken into account in the framework of BCS theory and relativistic quasiparticle RPA. Continuum RPA (CRPA) presents a robust method connected with an astonishing reduction of the numerical effort as compared to conventional methods. Modes of various multipolarities and isospin are investigated, in particular also the newly discovered Pygmy modes in the vicinity of the neutron evaporation threshold. The results are compared with conventional discrete RPA calculations as well as with experimental data. We find that the full treatment of the continuum is essential for light nuclei and the study of resonances in the neighborhood of the threshold. (orig.)

Relativistic continuum random phase approximation in spherical nuclei

Energy Technology Data Exchange (ETDEWEB)

Daoutidis, Ioannis

2009-10-01

Covariant density functional theory is used to analyze the nuclear response in the external multipole fields. The investigations are based on modern functionals with zero range and density dependent coupling constants. After a self-consistent solution of the Relativistic Mean Field (RMF) equations for the nuclear ground states multipole giant resonances are studied within the Relativistic Random Phase Approximation (RRPA), the small amplitude limit of the time-dependent RMF. The coupling to the continuum is treated precisely by calculating the single particle Greens-function of the corresponding Dirac equation. In conventional methods based on a discretization of the continuum this was not possible. The residual interaction is derived from the same RMF Lagrangian. This guarantees current conservation and a precise decoupling of the Goldstone modes. For nuclei with open shells pairing correlations are taken into account in the framework of BCS theory and relativistic quasiparticle RPA. Continuum RPA (CRPA) presents a robust method connected with an astonishing reduction of the numerical effort as compared to conventional methods. Modes of various multipolarities and isospin are investigated, in particular also the newly discovered Pygmy modes in the vicinity of the neutron evaporation threshold. The results are compared with conventional discrete RPA calculations as well as with experimental data. We find that the full treatment of the continuum is essential for light nuclei and the study of resonances in the neighborhood of the threshold. (orig.)

Linear-scaling implementation of the direct random-phase approximation

International Nuclear Information System (INIS)

Kállay, Mihály

2015-01-01

We report the linear-scaling implementation of the direct random-phase approximation (dRPA) for closed-shell molecular systems. As a bonus, linear-scaling algorithms are also presented for the second-order screened exchange extension of dRPA as well as for the second-order Møller–Plesset (MP2) method and its spin-scaled variants. Our approach is based on an incremental scheme which is an extension of our previous local correlation method [Rolik et al., J. Chem. Phys. 139, 094105 (2013)]. The approach extensively uses local natural orbitals to reduce the size of the molecular orbital basis of local correlation domains. In addition, we also demonstrate that using natural auxiliary functions [M. Kállay, J. Chem. Phys. 141, 244113 (2014)], the size of the auxiliary basis of the domains and thus that of the three-center Coulomb integral lists can be reduced by an order of magnitude, which results in significant savings in computation time. The new approach is validated by extensive test calculations for energies and energy differences. Our benchmark calculations also demonstrate that the new method enables dRPA calculations for molecules with more than 1000 atoms and 10 000 basis functions on a single processor

Collective nuclear excitations with Skyrme-second random-phase approximation

International Nuclear Information System (INIS)

Gambacurta, D.; Catara, F.; Grasso, M.

2010-01-01

Second random-phase approximation (RPA) calculations with a Skyrme force are performed to describe both high- and low-lying excited states in 16 O. The coupling between one particle-one hole and two particle-two hole as well as that between two particle-two hole configurations among themselves are fully taken into account, and the residual interaction is never neglected; we do not resort therefore to a generally used approximate scheme where only the first kind of coupling is considered. The issue of the rearrangement terms in the matrix elements beyond the standard RPA will be considered in detail in a forthcoming paper. Two approximations are employed here for these rearrangement terms: they are either neglected or evaluated with the RPA procedure. As a general feature of second RPA results, a several-MeV shift of the strength distribution to lower energies is systematically found with respect to RPA distributions. A much more important fragmentation of the strength is also naturally provided by the second RPA owing to the huge number of two particle-two hole configurations. A better description of the excitation energies of the low-lying 0 + and 2 + states is obtained with the second RPA than with the RPA.

Optimal dose selection accounting for patient subpopulations in a randomized Phase II trial to maximize the success probability of a subsequent Phase III trial.

Science.gov (United States)

Takahashi, Fumihiro; Morita, Satoshi

2018-02-08

Phase II clinical trials are conducted to determine the optimal dose of the study drug for use in Phase III clinical trials while also balancing efficacy and safety. In conducting these trials, it may be important to consider subpopulations of patients grouped by background factors such as drug metabolism and kidney and liver function. Determining the optimal dose, as well as maximizing the effectiveness of the study drug by analyzing patient subpopulations, requires a complex decision-making process. In extreme cases, drug development has to be terminated due to inadequate efficacy or severe toxicity. Such a decision may be based on a particular subpopulation. We propose a Bayesian utility approach (BUART) to randomized Phase II clinical trials which uses a first-order bivariate normal dynamic linear model for efficacy and safety in order to determine the optimal dose and study population in a subsequent Phase III clinical trial. We carried out a simulation study under a wide range of clinical scenarios to evaluate the performance of the proposed method in comparison with a conventional method separately analyzing efficacy and safety in each patient population. The proposed method showed more favorable operating characteristics in determining the optimal population and dose.

Safety and hemostatic efficacy of fibrin pad in partial nephrectomy: Results of an open-label Phase I and a randomized, standard-of-care-controlled Phase I/II study

Directory of Open Access Journals (Sweden)

Nativ Ofer

2012-11-01

Full Text Available Abstract Background Bleeding severity, anatomic location, tissue characteristics, and visibility are common challenges encountered while managing intraoperative bleeding, and conventional hemostatic measures (suture, ligature, and cautery may sometimes be ineffective or impractical. While topical absorbable hemostats (TAH are useful hemostatic adjuvants, each TAH has associated disadvantages. Methods We evaluated the safety and hemostatic efficacy of a new advanced biologic combination product―fibrin pad―to potentially address some gaps associated with TAHs. Fibrin pad was assessed as adjunctive hemostat in open partial nephrectomy in single-center, open-label, Phase I study (N = 10, and as primary hemostat in multicenter, single-blind, randomized, standard-of-care (SOC-controlled Phase I/II study (N = 7 in Israel. It was used to control mild-to-moderate bleeding in Phase I and also spurting arterial bleeding in Phase I/II study. Phase I study assessed safety and Phase I/II study, proportion of successes at 10 min following randomization, analyzed by Fisher exact tests at 5% significance level. Results Phase I (N = 10: All patients completed the study. Hemostasis was achieved within 3–4 min (average = 3.1 min of a single application in all patients. Fibrin pad was found to be safe for human use, with no product-related adverse events reported. Phase I/II (N = 7: Hemostatic success at 10 min (primary endpoint was achieved in 3/4 patients treated with fibrin pad versus 0/3 patients treated with SOC. No clinically significant change in laboratory or coagulation parameters was recorded, except a case of post-procedural hemorrhage with fibrin pad, which was considered serious and related to the fibrin pad treatment, and required re-operation. Although Data Safety Monitoring Board authorized trial continuation, the sponsor decided against proceeding toward an indication for primary treatment of severe arterial

Phase III Randomized Study of SB5, an Adalimumab Biosimilar, Versus Reference Adalimumab in Patients With Moderate‐to‐Severe Rheumatoid Arthritis

OpenAIRE

Weinblatt, Michael E.; Baranauskaite, Asta; Niebrzydowski, Jaroslaw; Dokoupilova, Eva; Zielinska, Agnieszka; Jaworski, Janusz; Racewicz, Artur; Pileckyte, Margarita; Jedrychowicz‐Rosiak, Krystyna; Cheong, Soo Yeon; Ghil, Jeehoon; Sokolovic, S.; Mekic, M.; Prodanovic, N.; Gajic, B.

2017-01-01

Objective SB5 is a biosimilar agent for adalimumab (ADA). The aim of this study was to evaluate the efficacy, pharmacokinetics (PK), safety, and immunogenicity of SB5 in comparison with reference ADA in patients with rheumatoid arthritis (RA). Methods In this phase III, randomized, double‐blind, parallel‐group study, patients with moderately to severely active RA despite treatment with methotrexate were randomized 1:1 to receive SB5 or reference ADA at a dosage of 40 mg subcutaneously every o...

Phase accuracy evaluation for phase-shifting fringe projection profilometry based on uniform-phase coded image

Science.gov (United States)

Zhang, Chunwei; Zhao, Hong; Zhu, Qian; Zhou, Changquan; Qiao, Jiacheng; Zhang, Lu

2018-06-01

Phase-shifting fringe projection profilometry (PSFPP) is a three-dimensional (3D) measurement technique widely adopted in industry measurement. It recovers the 3D profile of measured objects with the aid of the fringe phase. The phase accuracy is among the dominant factors that determine the 3D measurement accuracy. Evaluation of the phase accuracy helps refine adjustable measurement parameters, contributes to evaluating the 3D measurement accuracy, and facilitates improvement of the measurement accuracy. Although PSFPP has been deeply researched, an effective, easy-to-use phase accuracy evaluation method remains to be explored. In this paper, methods based on the uniform-phase coded image (UCI) are presented to accomplish phase accuracy evaluation for PSFPP. These methods work on the principle that the phase value of a UCI can be manually set to be any value, and once the phase value of a UCI pixel is the same as that of a pixel of a corresponding sinusoidal fringe pattern, their phase accuracy values are approximate. The proposed methods provide feasible approaches to evaluating the phase accuracy for PSFPP. Furthermore, they can be used to experimentally research the property of the random and gamma phase errors in PSFPP without the aid of a mathematical model to express random phase error or a large-step phase-shifting algorithm. In this paper, some novel and interesting phenomena are experimentally uncovered with the aid of the proposed methods.

Surface wake in the random-phase approximation

International Nuclear Information System (INIS)

Garcia de Abajo, F.J.; Echenique, P.M.

1993-01-01

The scalar-electric-potential distribution set up by an ion traveling in the vicinity of a plane solid-vacuum interface, that is, the surface-wake potential, is investigated with the specular-reflection model to describe the response of the surface and with the random-phase approximation for the dielectric function of the bulk material. This permits us to address the study of the low-velocity surface wake: the static potential is found to have a dip at the position of the ion; that dip is shifted towards the direction opposite to the velocity vector for velocities smaller than the threshold of creation of plasmons (∼1.3v F ). Extensive numerical calculations are presented for an ion both inside and outside aluminum. Comparison to the results obtained with the plasmon-pole dielectric function indicates excellent agreement for velocities larger than ∼1.3v F . On the other side, the possibility of surface-wake riding is suggested, by analogy with bulk-wake riding postulated in the past. In it, the electron would be bound in the first trough of the surface-wake potential set up when the ion describes a grazing trajectory. The main feature introduced by the surface with respect to the bulk consists of allowing the use of ions of higher charge, reducing in this way the relative importance of the electron self-energy, and in addition, giving rise to larger binding energies. When the ion beam is directed along a special direction of an oriented crystal surface, the mechanism of resonant coherent excitation could provide a way for experimentally detecting this phenomenon through the emission of the bound electron with well-defined energy and around a preferential direction

A randomized placebo-controlled phase III trial of oral laquinimod for multiple sclerosis

DEFF Research Database (Denmark)

Vollmer, T L; Sorensen, P S; Selmaj, K

2014-01-01

The phase III placebo-controlled BRAVO study assessed laquinimod effects in patients with relapsing-remitting MS (RRMS), and descriptively compared laquinimod with interferon beta (IFNβ)-1a (Avonex(®) reference arm). RRMS patients age 18-55 years with Expanded Disability Status Scale (EDSS) scores...... months. The primary endpoint was annualized relapse rate (ARR); secondary endpoints included percent brain volume change (PBVC) and 3-month confirmed disability worsening. In all, 1,331 patients were randomized: laquinimod (n = 434), placebo (n = 450), and IFNβ-1a (n = 447). ARR was not significantly...... reduced with laquinimod [-18 %, risk ratio (RR) = 0.82, 95 % CI 0.66-1.02; p = 0.075] vs. placebo. Laquinimod significantly reduced PBVC (28 %, p change in confirmed disability worsening with laquinimod measured...

Phase-only optical encryption based on the zeroth-order phase-contrast technique

Science.gov (United States)

Pizolato, José Carlos; Neto, Luiz Gonçalves

2009-09-01

A phase-only encryption/decryption scheme with the readout based on the zeroth-order phase-contrast technique (ZOPCT), without the use of a phase-changing plate on the Fourier plane of an optical system based on the 4f optical correlator, is proposed. The encryption of a gray-level image is achieved by multiplying the phase distribution obtained directly from the gray-level image by a random phase distribution. The robustness of the encoding is assured by the nonlinearity intrinsic to the proposed phase-contrast method and the random phase distribution used in the encryption process. The experimental system has been implemented with liquid-crystal spatial modulators to generate phase-encrypted masks and a decrypting key. The advantage of this method is the easy scheme to recover the gray-level information from the decrypted phase-only mask applying the ZOPCT. An analysis of this decryption method was performed against brute force attacks.

Assessment of correlation energies based on the random-phase approximation

International Nuclear Information System (INIS)

Paier, Joachim; Ren, Xinguo; Rinke, Patrick; Scheffler, Matthias; Scuseria, Gustavo E; Grüneis, Andreas; Kresse, Georg

2012-01-01

The random-phase approximation to the ground state correlation energy (RPA) in combination with exact exchange (EX) has brought the Kohn-Sham (KS) density functional theory one step closer towards a universal, ‘general purpose first-principles method’. In an effort to systematically assess the influence of several correlation energy contributions beyond RPA, this paper presents dissociation energies of small molecules and solids, activation energies for hydrogen transfer and non-hydrogen transfer reactions, as well as reaction energies for a number of common test sets. We benchmark EX + RPA and several flavors of energy functionals going beyond it: second-order screened exchange (SOSEX), single-excitation (SE) corrections, renormalized single-excitation (rSE) corrections and their combinations. Both the SE correction and the SOSEX contribution to the correlation energy significantly improve on the notorious tendency of EX + RPA to underbind. Surprisingly, activation energies obtained using EX + RPA based on a KS reference alone are remarkably accurate. RPA + SOSEX + rSE provides an equal level of accuracy for reaction as well as activation energies and overall gives the most balanced performance, because of which it can be applied to a wide range of systems and chemical reactions. (paper)

The random field Blume-Capel model revisited

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Santos, P. V.; da Costa, F. A.; de Araújo, J. M.

2018-04-01

We have revisited the mean-field treatment for the Blume-Capel model under the presence of a discrete random magnetic field as introduced by Kaufman and Kanner (1990). The magnetic field (H) versus temperature (T) phase diagrams for given values of the crystal field D were recovered in accordance to Kaufman and Kanner original work. However, our main goal in the present work was to investigate the distinct structures of the crystal field versus temperature phase diagrams as the random magnetic field is varied because similar models have presented reentrant phenomenon due to randomness. Following previous works we have classified the distinct phase diagrams according to five different topologies. The topological structure of the phase diagrams is maintained for both H - T and D - T cases. Although the phase diagrams exhibit a richness of multicritical phenomena we did not found any reentrant effect as have been seen in similar models.

A randomized trial of microdose leuprolide acetate protocol versus luteal phase ganirelix protocol in predicted poor responders.

Science.gov (United States)

DiLuigi, Andrea J; Engmann, Lawrence; Schmidt, David W; Benadiva, Claudio A; Nulsen, John C

2011-06-30

We performed a randomized trial to compare IVF outcomes in 54 poor responder patients undergoing a microdose leuprolide acetate (LA) protocol or a GnRH antagonist protocol incorporating a luteal phase E(2) patch and GnRH antagonist in the preceding menstrual cycle. Cancellation rates, number of oocytes retrieved, clinical pregnancy rates (PR), and ongoing PRs were similar between the two groups. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Toward a consistent random phase approximation based on the relativistic Hartree approximation

International Nuclear Information System (INIS)

Price, C.E.; Rost, E.; Shepard, J.R.; McNeil, J.A.

1992-01-01

We examine the random phase approximation (RPA) based on a relativistic Hartree approximation description for nuclear ground states. This model includes contributions from the negative energy sea at the one-loop level. We emphasize consistency between the treatment of the ground state and the RPA. This consistency is important in the description of low-lying collective levels but less important for the longitudinal (e,e') quasielastic response. We also study the effect of imposing a three-momentum cutoff on negative energy sea contributions. A cutoff of twice the nucleon mass improves agreement with observed spin-orbit splittings in nuclei compared to the standard infinite cutoff results, an effect traceable to the fact that imposing the cutoff reduces m * /m. Consistency is much more important than the cutoff in the description of low-lying collective levels. The cutoff model also provides excellent agreement with quasielastic (e,e') data

Accurate Quasiparticle Spectra from the T-Matrix Self-Energy and the Particle-Particle Random Phase Approximation.

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Zhang, Du; Su, Neil Qiang; Yang, Weitao

2017-07-20

The GW self-energy, especially G 0 W 0 based on the particle-hole random phase approximation (phRPA), is widely used to study quasiparticle (QP) energies. Motivated by the desirable features of the particle-particle (pp) RPA compared to the conventional phRPA, we explore the pp counterpart of GW, that is, the T-matrix self-energy, formulated with the eigenvectors and eigenvalues of the ppRPA matrix. We demonstrate the accuracy of the T-matrix method for molecular QP energies, highlighting the importance of the pp channel for calculating QP spectra.

Insight into organic reactions from the direct random phase approximation and its corrections

Energy Technology Data Exchange (ETDEWEB)

Ruzsinszky, Adrienn [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Zhang, Igor Ying; Scheffler, Matthias [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany)

2015-10-14

The performance of the random phase approximation (RPA) and beyond-RPA approximations for the treatment of electron correlation is benchmarked on three different molecular test sets. The test sets are chosen to represent three typical sources of error which can contribute to the failure of most density functional approximations in chemical reactions. The first test set (atomization and n-homodesmotic reactions) offers a gradually increasing balance of error from the chemical environment. The second test set (Diels-Alder reaction cycloaddition = DARC) reflects more the effect of weak dispersion interactions in chemical reactions. Finally, the third test set (self-interaction error 11 = SIE11) represents reactions which are exposed to noticeable self-interaction errors. This work seeks to answer whether any one of the many-body approximations considered here successfully addresses all these challenges.

Insight into organic reactions from the direct random phase approximation and its corrections

International Nuclear Information System (INIS)

Ruzsinszky, Adrienn; Zhang, Igor Ying; Scheffler, Matthias

2015-01-01

The performance of the random phase approximation (RPA) and beyond-RPA approximations for the treatment of electron correlation is benchmarked on three different molecular test sets. The test sets are chosen to represent three typical sources of error which can contribute to the failure of most density functional approximations in chemical reactions. The first test set (atomization and n-homodesmotic reactions) offers a gradually increasing balance of error from the chemical environment. The second test set (Diels-Alder reaction cycloaddition = DARC) reflects more the effect of weak dispersion interactions in chemical reactions. Finally, the third test set (self-interaction error 11 = SIE11) represents reactions which are exposed to noticeable self-interaction errors. This work seeks to answer whether any one of the many-body approximations considered here successfully addresses all these challenges

Phase III Randomized Clinical Trial Comparing Tremelimumab With Standard-of-Care Chemotherapy in Patients With Advanced Melanoma

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Ribas, Antoni; Kefford, Richard; Marshall, Margaret A.; Punt, Cornelis J.A.; Haanen, John B.; Marmol, Maribel; Garbe, Claus; Gogas, Helen; Schachter, Jacob; Linette, Gerald; Lorigan, Paul; Kendra, Kari L.; Maio, Michele; Trefzer, Uwe; Smylie, Michael; McArthur, Grant A.; Dreno, Brigitte; Nathan, Paul D.; Mackiewicz, Jacek; Kirkwood, John M.; Gomez-Navarro, Jesus; Huang, Bo; Pavlov, Dmitri; Hauschild, Axel

2013-01-01

Purpose In phase I/II trials, the cytotoxic T lymphocyte–associated antigen-4–blocking monoclonal antibody tremelimumab induced durable responses in a subset of patients with advanced melanoma. This phase III study evaluated overall survival (OS) and other safety and efficacy end points in patients with advanced melanoma treated with tremelimumab or standard-of-care chemotherapy. Patients and Methods Patients with treatment-naive, unresectable stage IIIc or IV melanoma were randomly assigned at a ratio of one to one to tremelimumab (15 mg/kg once every 90 days) or physician's choice of standard-of-care chemotherapy (temozolomide or dacarbazine). Results In all, 655 patients were enrolled and randomly assigned. The test statistic crossed the prespecified futility boundary at second interim analysis after 340 deaths, but survival follow-up continued. At final analysis with 534 events, median OS by intent to treat was 12.6 months (95% CI, 10.8 to 14.3) for tremelimumab and 10.7 months (95% CI, 9.36 to 11.96) for chemotherapy (hazard ratio, 0.88; P = .127). Objective response rates were similar in the two arms: 10.7% in the tremelimumab arm and 9.8% in the chemotherapy arm. However, response duration (measured from date of random assignment) was significantly longer after tremelimumab (35.8 v 13.7 months; P = .0011). Diarrhea, pruritus, and rash were the most common treatment-related adverse events in the tremelimumab arm; 7.4% had endocrine toxicities. Seven deaths in the tremelimumab arm and one in the chemotherapy arm were considered treatment related by either investigators or sponsor. Conclusion This study failed to demonstrate a statistically significant survival advantage of treatment with tremelimumab over standard-of-care chemotherapy in first-line treatment of patients with metastatic melanoma. PMID:23295794

Phase III randomized clinical trial comparing tremelimumab with standard-of-care chemotherapy in patients with advanced melanoma.

Science.gov (United States)

Ribas, Antoni; Kefford, Richard; Marshall, Margaret A; Punt, Cornelis J A; Haanen, John B; Marmol, Maribel; Garbe, Claus; Gogas, Helen; Schachter, Jacob; Linette, Gerald; Lorigan, Paul; Kendra, Kari L; Maio, Michele; Trefzer, Uwe; Smylie, Michael; McArthur, Grant A; Dreno, Brigitte; Nathan, Paul D; Mackiewicz, Jacek; Kirkwood, John M; Gomez-Navarro, Jesus; Huang, Bo; Pavlov, Dmitri; Hauschild, Axel

2013-02-10

In phase I/II trials, the cytotoxic T lymphocyte-associated antigen-4-blocking monoclonal antibody tremelimumab induced durable responses in a subset of patients with advanced melanoma. This phase III study evaluated overall survival (OS) and other safety and efficacy end points in patients with advanced melanoma treated with tremelimumab or standard-of-care chemotherapy. Patients with treatment-naive, unresectable stage IIIc or IV melanoma were randomly assigned at a ratio of one to one to tremelimumab (15 mg/kg once every 90 days) or physician's choice of standard-of-care chemotherapy (temozolomide or dacarbazine). In all, 655 patients were enrolled and randomly assigned. The test statistic crossed the prespecified futility boundary at second interim analysis after 340 deaths, but survival follow-up continued. At final analysis with 534 events, median OS by intent to treat was 12.6 months (95% CI, 10.8 to 14.3) for tremelimumab and 10.7 months (95% CI, 9.36 to 11.96) for chemotherapy (hazard ratio, 0.88; P = .127). Objective response rates were similar in the two arms: 10.7% in the tremelimumab arm and 9.8% in the chemotherapy arm. However, response duration (measured from date of random assignment) was significantly longer after tremelimumab (35.8 v 13.7 months; P = .0011). Diarrhea, pruritus, and rash were the most common treatment-related adverse events in the tremelimumab arm; 7.4% had endocrine toxicities. Seven deaths in the tremelimumab arm and one in the chemotherapy arm were considered treatment related by either investigators or sponsor. This study failed to demonstrate a statistically significant survival advantage of treatment with tremelimumab over standard-of-care chemotherapy in first-line treatment of patients with metastatic melanoma.

CrowdPhase: crowdsourcing the phase problem

International Nuclear Information System (INIS)

Jorda, Julien; Sawaya, Michael R.; Yeates, Todd O.

2014-01-01

The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

CrowdPhase: crowdsourcing the phase problem

Energy Technology Data Exchange (ETDEWEB)

Jorda, Julien; Sawaya, Michael R. [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Yeates, Todd O., E-mail: yeates@mbi.ucla.edu [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Molecular Biology Institute, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); University of California, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States)

2014-06-01

The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

Dietary Soy Supplement on Fibromyalgia Symptoms: A Randomized, Double-Blind, Placebo-Controlled, Early Phase Trial

Directory of Open Access Journals (Sweden)

Dietlind L. Wahner-Roedler

2011-01-01

Full Text Available Most patients with fibromyalgia use complementary and alternative medicine (CAM. Properly designed controlled trials are necessary to assess the effectiveness of these practices. This study was a randomized, double-blind, placebo-controlled, early phase trial. Fifty patients seen at a fibromyalgia outpatient treatment program were randomly assigned to a daily soy or placebo (casein shake. Outcome measures were scores of the Fibromyalgia Impact Questionnaire (FIQ and the Center for Epidemiologic Studies Depression Scale (CES-D at baseline and after 6 weeks of intervention. Analysis was with standard statistics based on the null hypothesis, and separation test for early phase CAM comparative trials. Twenty-eight patients completed the study. Use of standard statistics with intent-to-treat analysis showed that total FIQ scores decreased by 14% in the soy group (P = .02 and by 18% in the placebo group (P < .001. The difference in change in scores between the groups was not significant (P = .16. With the same analysis, CES-D scores decreased in the soy group by 16% (P = .004 and in the placebo group by 15% (P = .05. The change in scores was similar in the groups (P = .83. Results of statistical analysis using the separation test and intent-to-treat analysis revealed no benefit of soy compared with placebo. Shakes that contain soy and shakes that contain casein, when combined with a multidisciplinary fibromyalgia treatment program, provide a decrease in fibromyalgia symptoms. Separation between the effects of soy and casein (control shakes did not favor the intervention. Therefore, large-sample studies using soy for patients with fibromyalgia are probably not indicated.

Tensor hypercontracted ppRPA: Reducing the cost of the particle-particle random phase approximation from O(r 6) to O(r 4)

International Nuclear Information System (INIS)

Shenvi, Neil; Yang, Yang; Yang, Weitao; Aggelen, Helen van

2014-01-01

In recent years, interest in the random-phase approximation (RPA) has grown rapidly. At the same time, tensor hypercontraction has emerged as an intriguing method to reduce the computational cost of electronic structure algorithms. In this paper, we combine the particle-particle random phase approximation with tensor hypercontraction to produce the tensor-hypercontracted particle-particle RPA (THC-ppRPA) algorithm. Unlike previous implementations of ppRPA which scale as O(r 6 ), the THC-ppRPA algorithm scales asymptotically as only O(r 4 ), albeit with a much larger prefactor than the traditional algorithm. We apply THC-ppRPA to several model systems and show that it yields the same results as traditional ppRPA to within mH accuracy. Our method opens the door to the development of post-Kohn Sham functionals based on ppRPA without the excessive asymptotic cost of traditional ppRPA implementations

Strong disorder real-space renormalization for the many-body-localized phase of random Majorana models

Science.gov (United States)

Monthus, Cécile

2018-03-01

For the many-body-localized phase of random Majorana models, a general strong disorder real-space renormalization procedure known as RSRG-X (Pekker et al 2014 Phys. Rev. X 4 011052) is described to produce the whole set of excited states, via the iterative construction of the local integrals of motion (LIOMs). The RG rules are then explicitly derived for arbitrary quadratic Hamiltonians (free-fermions models) and for the Kitaev chain with local interactions involving even numbers of consecutive Majorana fermions. The emphasis is put on the advantages of the Majorana language over the usual quantum spin language to formulate unified RSRG-X rules.

Broadband diffuse terahertz wave scattering by flexible metasurface with randomized phase distribution.

Science.gov (United States)

Zhang, Yin; Liang, Lanju; Yang, Jing; Feng, Yijun; Zhu, Bo; Zhao, Junming; Jiang, Tian; Jin, Biaobing; Liu, Weiwei

2016-05-26

Suppressing specular electromagnetic wave reflection or backward radar cross section is important and of broad interests in practical electromagnetic engineering. Here, we present a scheme to achieve broadband backward scattering reduction through diffuse terahertz wave reflection by a flexible metasurface. The diffuse scattering of terahertz wave is caused by the randomized reflection phase distribution on the metasurface, which consists of meta-particles of differently sized metallic patches arranged on top of a grounded polyimide substrate simply through a certain computer generated pseudorandom sequence. Both numerical simulations and experimental results demonstrate the ultralow specular reflection over a broad frequency band and wide angle of incidence due to the re-distribution of the incident energy into various directions. The diffuse scattering property is also polarization insensitive and can be well preserved when the flexible metasurface is conformably wrapped on a curved reflective object. The proposed design opens up a new route for specular reflection suppression, and may be applicable in stealth and other technology in the terahertz spectrum.

SANS [small-angle neutron scattering] evaluation of the RPA [random phase approximation] theory for binary homopolymer mixtures

International Nuclear Information System (INIS)

Bates, F.S.; Koehler, W.C.; Wignall, G.D.; Fetters, L.J.

1986-12-01

A well characterized binary mixture of normal (protonated) and perdeuterated monodisperse 1,2 polybutenes has been studied by small-angle neutron scattering (SANS). For scattering wavevectors q greater than the inverse radius-of-gyration R/sub g/ -1 , the SANS intensity is quantitatively predicted by the random phase approximation (RPA) theory of deGennes over all measured values of the segment-segment interaction parameter Chi. In the region (Chi s-Chi)Chi s -1 > 0.5 the interaction parameter determined using the RPA theory for q > R/sub g/ -1 is greater than that calculated from the zero-angle intensity based on an Ornstein-Zernike plot, where Chi s represents the limit of single phase stability. These findings indicate a correlation between the critical fluctuation length ξ and R/sub g/ which is not accounted for by the RPA theory

Large-Scale Cubic-Scaling Random Phase Approximation Correlation Energy Calculations Using a Gaussian Basis.

Science.gov (United States)

Wilhelm, Jan; Seewald, Patrick; Del Ben, Mauro; Hutter, Jürg

2016-12-13

We present an algorithm for computing the correlation energy in the random phase approximation (RPA) in a Gaussian basis requiring [Formula: see text] operations and [Formula: see text] memory. The method is based on the resolution of the identity (RI) with the overlap metric, a reformulation of RI-RPA in the Gaussian basis, imaginary time, and imaginary frequency integration techniques, and the use of sparse linear algebra. Additional memory reduction without extra computations can be achieved by an iterative scheme that overcomes the memory bottleneck of canonical RPA implementations. We report a massively parallel implementation that is the key for the application to large systems. Finally, cubic-scaling RPA is applied to a thousand water molecules using a correlation-consistent triple-ζ quality basis.

β-decay rates of r-process nuclei in the relativistic quasiparticle random phase approximation

International Nuclear Information System (INIS)

Niksic, T.; Marketin, T.; Vretenar, D.; Paar, N.; Ring, P.

2005-01-01

The fully consistent relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is employed in the calculation of β-decay half-lives of neutron-rich nuclei in the N≅50 and N≅82 regions. A new density-dependent effective interaction, with an enhanced value of the nucleon effective mass, is used in relativistic Hartree-Bogoliubov calculation of nuclear ground states and in the particle-hole channel of the PN-RQRPA. The finite range Gogny D1S interaction is employed in the T=1 pairing channel, and the model also includes a proton-neutron particle-particle interaction. The theoretical half-lives reproduce the experimental data for the Fe, Zn, Cd, and Te isotopic chains but overestimate the lifetimes of Ni isotopes and predict a stable 132 Sn

Collective excitations in the Penson-Kolb model: A generalized random-phase-approximation study

International Nuclear Information System (INIS)

Roy, G.K.; Bhattacharyya, B.

1997-01-01

The evolution of the superconducting ground state of the half-filled Penson-Kolb model is examined as a function of the coupling constant using a mean-field approach and the generalized random phase approximation (RPA) in two and three dimensions. On-site singlet pairs hop to compete against single-particle motion in this model, giving the coupling constant a strong momentum dependence. There is a pronounced bandwidth enhancement effect that converges smoothly to a finite value in the strong-coupling (Bose) regime. The low-lying collective excitations evaluated in generalized RPA show a linear dispersion and a gradual crossover from the weak-coupling (BCS) limit to the Bose regime; the mode velocity increases monotonically in sharp contrast to the attractive Hubbard model. Analytical results are derived in the asymptotic limits. copyright 1997 The American Physical Society

Randomized Phase III and Extension Studies of Naldemedine in Patients With Opioid-Induced Constipation and Cancer.

Science.gov (United States)

Katakami, Nobuyuki; Harada, Toshiyuki; Murata, Toru; Shinozaki, Katsunori; Tsutsumi, Masakazu; Yokota, Takaaki; Arai, Masatsugu; Tada, Yukio; Narabayashi, Masaru; Boku, Narikazu

2017-12-01

Purpose Opioid-induced constipation (OIC) is a frequent and debilitating adverse effect (AE) of opioids-common analgesics for cancer pain. We investigated the efficacy and safety of a peripherally acting μ-opioid receptor antagonist, naldemedine (S-297995), for OIC, specifically in patients with cancer. Patients and Methods This phase III trial consisted of a 2-week, randomized, double-blind, placebo-controlled study (COMPOSE-4) and an open-label, 12-week extension study (COMPOSE-5). In COMPOSE-4, eligible adults with OIC and cancer were randomly assigned on a 1:1 basis to receive once-daily oral naldemedine 0.2 mg or placebo. The primary end point was the proportion of spontaneous bowel movement (SBM) responders (≥ 3 SBMs/week and an increase of ≥ 1 SBM/week from baseline). The primary end point of COMPOSE-5 was safety. Results In COMPOSE-4, 193 eligible patients were randomly assigned to naldemedine (n = 97) or placebo (n = 96). The proportion of SBM responders in COMPOSE-4 was significantly greater with naldemedine than with placebo (71.1% [69 of 97 patients] v 34.4% [33 of 96 patients]; P opioid withdrawal and had no notable impact on opioid-mediated analgesia. Conclusion Once-daily oral naldemedine 0.2 mg effectively treated OIC and was generally well tolerated in patients with OIC and cancer.

A randomized, phase 1/2 trial of the safety, tolerability, and immunogenicity of bivalent rLP2086 meningococcal B vaccine in healthy infants.

Science.gov (United States)

Martinon-Torres, Federico; Gimenez-Sanchez, Francisco; Bernaola-Iturbe, Enrique; Diez-Domingo, Javier; Jiang, Qin; Perez, John L

2014-09-08

Neisseria meningitidis serogroup B (MnB) is a major cause of invasive meningococcal disease in infants. A conserved, surface-exposed lipoprotein, LP2086 (a factor H-binding protein [fHBP]), is a promising MnB vaccine target. A bivalent, recombinant vaccine targeting the fHBP (rLP2086) of MnB was developed. This phase 1/2 clinical study was designed to assess the immunogenicity, safety, and tolerability of a 4-dose series of the rLP2086 vaccine at 20-, 60-, 120-, or 200-μg dose levels in vaccine-naive infants when given with routine childhood vaccines. The study was to consist of two phases: a single-blind sentinel phase and an open-label full enrollment phase. During the sentinel phase, randomization of subjects to the next higher dose was delayed pending a 14-day safety review of dose 1 of the preceding dose cohort. The full enrollment phase was to occur after completion of the sentinel phase. Local reactions were generally mild and adverse events infrequent; however, after only 46 infants were randomized into the study, fever rates were 64% and 90% in subjects receiving one 20- or 60-μg rLP2086 dose, respectively. Most fevers were group and 1 subject in the 60-μg group experienced fevers >39.0°C; no fevers were >40.0°C. Due to these high fever rates, the study was terminated early. No immunogenicity data were collected. This report discusses the safety and acceptability of rLP2086 in infants after one 20- or 60-μg dose. Due to the high fever rate experienced in the 20- and 60-μg groups, rLP2086 in the current formulation may not be acceptable for infants. Copyright © 2014. Published by Elsevier Ltd.

Electric dipole strength and dipole polarizability in 48Ca within a fully self-consistent second random-phase approximation

Science.gov (United States)

Gambacurta, D.; Grasso, M.; Vasseur, O.

2018-02-01

The second random-phase-approximation model corrected by a subtraction procedure designed to cure double counting, instabilities, and ultraviolet divergences, is employed for the first time to analyze the dipole strength and polarizability in 48Ca. All the terms of the residual interaction are included, leading to a fully self-consistent scheme. Results are illustrated with two Skyrme parametrizations, SGII and SLy4. Those obtained with the SGII interaction are particularly satisfactory. In this case, the low-lying strength below the neutron threshold is well reproduced and the giant dipole resonance is described in a very satisfactory way especially in its spreading and fragmentation. Spreading and fragmentation are produced in a natural way within such a theoretical model by the coupling of 1 particle-1 hole and 2 particle-2 hole configurations. Owing to this feature, we may provide for the electric polarizability as a function of the excitation energy a curve with a similar slope around the centroid energy of the giant resonance compared to the corresponding experimental results. This represents a considerable improvement with respect to previous theoretical predictions obtained with the random-phase approximation or with several ab-initio models. In such cases, the spreading width of the excitation cannot be reproduced and the polarizability as a function of the excitation energy displays a stiff increase around the predicted centroid energy of the giant resonance.

Optical image encryption based on interference under convergent random illumination

International Nuclear Information System (INIS)

Kumar, Pramod; Joseph, Joby; Singh, Kehar

2010-01-01

In an optical image encryption system based on the interference principle, two pure phase masks are designed analytically to hide an image. These two masks are illuminated with a plane wavefront to retrieve the original image in the form of an interference pattern at the decryption plane. Replacement of the plane wavefront with convergent random illumination in the proposed scheme leads to an improvement in the security of interference based encryption. The proposed encryption scheme retains the simplicity of an interference based method, as the two pure masks are generated with an analytical method without any iterative algorithm. In addition to the free-space propagation distance and the two pure phase masks, the convergence distance and the randomized lens phase function are two new encryption parameters to enhance the system security. The robustness of this scheme against occlusion of the random phase mask of the randomized lens phase function is investigated. The feasibility of the proposed scheme is demonstrated with numerical simulation results

Unbiased All-Optical Random-Number Generator

Science.gov (United States)

Steinle, Tobias; Greiner, Johannes N.; Wrachtrup, Jörg; Giessen, Harald; Gerhardt, Ilja

2017-10-01

The generation of random bits is of enormous importance in modern information science. Cryptographic security is based on random numbers which require a physical process for their generation. This is commonly performed by hardware random-number generators. These often exhibit a number of problems, namely experimental bias, memory in the system, and other technical subtleties, which reduce the reliability in the entropy estimation. Further, the generated outcome has to be postprocessed to "iron out" such spurious effects. Here, we present a purely optical randomness generator, based on the bistable output of an optical parametric oscillator. Detector noise plays no role and postprocessing is reduced to a minimum. Upon entering the bistable regime, initially the resulting output phase depends on vacuum fluctuations. Later, the phase is rigidly locked and can be well determined versus a pulse train, which is derived from the pump laser. This delivers an ambiguity-free output, which is reliably detected and associated with a binary outcome. The resulting random bit stream resembles a perfect coin toss and passes all relevant randomness measures. The random nature of the generated binary outcome is furthermore confirmed by an analysis of resulting conditional entropies.

Relativistic Random-Phase Approximation with Density-dependent Meson-nucleon Couplings at Finite Temperature

International Nuclear Information System (INIS)

Niu, Y.; Paar, N.; Vretenar, D.; Meng, J.

2009-01-01

The fully self-consistent relativistic random-phase approximation (RRPA) framework based on effective interactions with a phenomenological density dependence is extended to finite temperatures. The RRPA configuration space is built from the spectrum of single-nucleon states at finite temperature obtained by the temperature dependent relativistic mean field (RMF-T) theory based on effective Lagrangian with density dependent meson-nucleon vertex functions. As an illustration, the dependence of binding energy, radius, entropy and single particle levels on temperature for spherical nucleus 2 08P b is investigated in RMF-T theory. The finite temperature RRPA has been employed in studies of giant monopole and dipole resonances, and the evolution of resonance properties has been studied as a function of temperature. In addition, exotic modes of excitation have been systematically explored at finite temperatures, with an emphasis on the case of pygmy dipole resonances.(author)

Monte Carlo studies of two-dimensional random-anisotropy magnets

Science.gov (United States)

Denholm, D. R.; Sluckin, T. J.

1993-07-01

We have carried out a systematic set of Monte Carlo simulations of the Harris-Plischke-Zuckermann lattice model of random magnetic anisotropy on a two-dimensional square lattice, using the classical Metropolis algorithm. We have considered varying temperature T, external magnetic field H (both in the reproducible and irreproducible limits), time scale of the simulation τ in Monte Carlo steps and anisotropy ratio D/J. In the absence of randomness this model reduces to the XY model in two dimensions, which possesses the familiar Kosterlitz-Thouless low-temperature phase with algebraic but no long-range order. In the presence of random anisotropy we find evidence of a low-temperature phase with some disordered features, which might be identified with a spin-glass phase. The low-temperature Kosterlitz-Thouless phase survives at intermediate temperatures for low randomness, but is no longer present for large D/J. We have also studied the high-H approach to perfect order, for which there are theoretical predictions due to Chudnovsky.

Finite nucleus Dirac mean field theory and random phase approximation using finite B splines

International Nuclear Information System (INIS)

McNeil, J.A.; Furnstahl, R.J.; Rost, E.; Shepard, J.R.; Department of Physics, University of Maryland, College Park, Maryland 20742; Department of Physics, University of Colorado, Boulder, Colorado 80309)

1989-01-01

We calculate the finite nucleus Dirac mean field spectrum in a Galerkin approach using finite basis splines. We review the method and present results for the relativistic σ-ω model for the closed-shell nuclei 16 O and 40 Ca. We study the convergence of the method as a function of the size of the basis and the closure properties of the spectrum using an energy-weighted dipole sum rule. We apply the method to the Dirac random-phase-approximation response and present results for the isoscalar 1/sup -/ and 3/sup -/ longitudinal form factors of 16 O and 40 Ca. We also use a B-spline spectral representation of the positive-energy projector to evaluate partial energy-weighted sum rules and compare with nonrelativistic sum rule results

β-decay rates of r-process nuclei in the relativistic quasiparticle random phase approximation

International Nuclear Information System (INIS)

Niksic, T.; Marketin, T.; Vretenar, D.; Paar, N.; Ring, P.

2004-01-01

The fully consistent relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is employed in the calculation of β-decay half-lives of neutron-rich nuclei in the N∼50 and N∼82 regions. A new density-dependent effective interaction, with an enhanced value of the nucleon effective mass, is used in relativistic Hartree-Bogolyubov calculation of nuclear ground states and in the particle-hole channel of the PN-RQRPA. The finite range Gogny D1S interaction is employed in the T=1 pairing channel, and the model also includes a proton-neutron particle-particle interaction. The theoretical half-lives reproduce the experimental data for the Fe, Zn, Cd, and Te isotopic chains, but overestimate the lifetimes of Ni isotopes and predict a stable 132 Sn. (orig.)

{beta}-decay rates of r-process nuclei in the relativistic quasiparticle random phase approximation

Energy Technology Data Exchange (ETDEWEB)

Niksic, T.; Marketin, T.; Vretenar, D. [Zagreb Univ. (Croatia). Faculty of Science, Physics Dept.; Paar, N. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik; Ring, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

2004-12-08

The fully consistent relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is employed in the calculation of {beta}-decay half-lives of neutron-rich nuclei in the N{approx}50 and N{approx}82 regions. A new density-dependent effective interaction, with an enhanced value of the nucleon effective mass, is used in relativistic Hartree-Bogolyubov calculation of nuclear ground states and in the particle-hole channel of the PN-RQRPA. The finite range Gogny D1S interaction is employed in the T=1 pairing channel, and the model also includes a proton-neutron particle-particle interaction. The theoretical half-lives reproduce the experimental data for the Fe, Zn, Cd, and Te isotopic chains, but overestimate the lifetimes of Ni isotopes and predict a stable {sup 132}Sn. (orig.)

Microstructure of two-phase random media. II. The Mayer--Montroll and Kirkwood--Salsburg hierarchies

International Nuclear Information System (INIS)

Torquato, S.; Stell, G.

1983-01-01

It is shown that the Mayer--Montroll (MM) and Kirkwood--Salsburg (KS) hierarchies of equilibrium statistical mechanics for a binary mixture under certain limits become equations for the n-point matrix probability functions S/sub n/ associated with two-phase random media. The MM representation proves to be identical to the S/sub n/ expression derived by us in a previous paper, whereas the KS representation is different and new. These results are shown to illuminate our understanding of the S/sub n/ from both a physical and quantitative point of view. In particular rigorous upper and lower bounds on the S/sub n/ are obtained for a two-phase medium formed so as to be in a state of thermal equilibrium. For such a medium consisting of impenetrable-sphere inclusions in a matrix, a new exact expression is also given for S/sub n/ in terms of a two-body probability distribution function rho/sub 2/ as well as new expressions for S/sub 3/ in terms of rho/sub 2/ and rho/sub 3/, a three-body distribution function. Physical insight into the nature of these results is given by extending some geometrical arguments originally put forth by Boltzmann

Stereotactic ablative radiotherapy for comprehensive treatment of oligometastatic tumors (SABR-COMET): Study protocol for a randomized phase II trial

International Nuclear Information System (INIS)

Palma, David A; Griffioen, GwendolynHMJ; Gaede, Stewart; Slotman, Ben; Senan, Suresh; Haasbeek, Cornelis J A; Rodrigues, George B; Dahele, Max; Lock, Michael; Yaremko, Brian; Olson, Robert; Liu, Mitchell; Panarotto, Jason

2012-01-01

Stereotactic ablative radiotherapy (SABR) has emerged as a new treatment option for patients with oligometastatic disease. SABR delivers precise, high-dose, hypofractionated radiotherapy, and achieves excellent rates of local control. Survival outcomes for patients with oligometastatic disease treated with SABR appear promising, but conclusions are limited by patient selection, and the lack of adequate controls in most studies. The goal of this multicenter randomized phase II trial is to assess the impact of a comprehensive oligometastatic SABR treatment program on overall survival and quality of life in patients with up to 5 metastatic cancer lesions, compared to patients who receive standard of care treatment alone. After stratification by the number of metastases (1-3 vs. 4-5), patients will be randomized between Arm 1: current standard of care treatment, and Arm 2: standard of care treatment + SABR to all sites of known disease. Patients will be randomized in a 1:2 ratio to Arm 1:Arm 2, respectively. For patients receiving SABR, radiotherapy dose and fractionation depends on the site of metastasis and the proximity to critical normal structures. This study aims to accrue a total of 99 patients within four years. The primary endpoint is overall survival, and secondary endpoints include quality of life, toxicity, progression-free survival, lesion control rate, and number of cycles of further chemotherapy/systemic therapy. This study will provide an assessment of the impact of SABR on clinical outcomes and quality of life, to determine if long-term survival can be achieved for selected patients with oligometastatic disease, and will inform the design of a possible phase III study. Clinicaltrials.gov identifier: NCT01446744

Diffusion in porous structures containing three fluid phases

International Nuclear Information System (INIS)

Galani, A.N.; Kainourgiakis, M.E.; Stubos, A.K.; Kikkinides, E.S.

2005-01-01

In the present study, the tracer diffusion in porous media filled by three fluid phases (a non-wetting, an intermediate wetting and a wetting phase) is investigated. The disordered porous structure of porous systems like random sphere packing and the North Sea chalk, is represented by three-dimensional binary images. The random sphere pack is generated by a standard ballistic deposition procedure, while the chalk matrix by a stochastic reconstruction technique. Physically sound spatial distributions of the three phases filling the pore space are determined by the use of a simulated annealing algorithm, where those phases are initially randomly distributed in the pore space and trial-and-error swaps are performed in order to attain the global minimum of the total interfacial energy. The acceptance rule for a trial move during the annealing is modified properly improving the efficiency of the technique. The diffusivities of the resulting domains are computed by a random walk method. A parametric study with respect to the pore volume fraction occupied by each fluid phase and the ratio of the diffusivities in the fluid phases is performed. (authors)

Two spatial light modulator system for laboratory simulation of random beam propagation in random media.

Science.gov (United States)

Wang, Fei; Toselli, Italo; Korotkova, Olga

2016-02-10

An optical system consisting of a laser source and two independent consecutive phase-only spatial light modulators (SLMs) is shown to accurately simulate a generated random beam (first SLM) after interaction with a stationary random medium (second SLM). To illustrate the range of possibilities, a recently introduced class of random optical frames is examined on propagation in free space and several weak turbulent channels with Kolmogorov and non-Kolmogorov statistics.

A phase II randomized trial of Observation versus stereotactic ablative RadiatIon for OLigometastatic prostate CancEr (ORIOLE).

Science.gov (United States)

Radwan, Noura; Phillips, Ryan; Ross, Ashley; Rowe, Steven P; Gorin, Michael A; Antonarakis, Emmanuel S; Deville, Curtiland; Greco, Stephen; Denmeade, Samuel; Paller, Channing; Song, Daniel Y; Diehn, Maximilian; Wang, Hao; Carducci, Michael; Pienta, Kenneth J; Pomper, Martin G; DeWeese, Theodore L; Dicker, Adam; Eisenberger, Mario; Tran, Phuoc T

2017-06-29

We describe a randomized, non-blinded Phase II interventional study to assess the safety and efficacy of stereotactic ablative radiotherapy (SABR) for hormone-sensitive oligometastatic prostate adenocarcinoma, and to describe the biology of the oligometastatic state using immunologic, cellular, molecular, and functional imaging correlates. 54 men with oligometastatic prostate adenocarcinoma will be accrued. The primary clinical endpoint will be progression at 6 months from randomization with the hypothesis that SABR to all metastases will forestall progression by disrupting the metastatic process. Secondary clinical endpoints will include local control at 6 months post-SABR, toxicity and quality of life, and androgen deprivation therapy (ADT)-free survival (ADT-FS). Further fundamental analysis of the oligometastatic state with be achieved through correlation with investigational 18 F-DCFPyL PET/CT imaging and measurement of circulating tumor cells, circulating tumor DNA, and circulating T-cell receptor repertoires, facilitating an unprecedented opportunity to characterize, in isolation, the effects of SABR on the dynamics of and immunologic response to oligometastatic disease. Patients will be randomized 2:1 to SABR or observation with minimization to balance assignment by primary intervention, prior hormonal therapy, and PSA doubling time. Progression after 6 months will be compared using Fisher's exact test. Hazard ratios and Kaplan-Meier estimates of progression free survival (PFS), ADT free survival (ADT-FS), time to locoregional progression (TTLP) and time to distant progression (TTDP) will be calculated based on an intention-to-treat. Local control will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Withdrawal from the study prior to 6 months will be counted as progression. Adverse events will be summarized by type and grade. Quality of life pre- and post- SABR will be measured by Brief Pain Inventory. The ORIOLE

Rikkunshito for Preventing Chemotherapy-Induced Nausea and Vomiting in Lung Cancer Patients: Results from 2 Prospective, Randomized Phase 2 Trials

Directory of Open Access Journals (Sweden)

Toshiyuki Harada

2018-01-01

Full Text Available The herbal medicine rikkunshito has the potential to improve chemotherapy-induced nausea and vomiting (CINV by stimulating ghrelin secretion. We aimed to evaluate the efficacy and safety of rikkunshito in preventing CINV for patients with lung cancer. Two separate prospective, randomized, phase II parallel design studies were conducted in patients with lung cancer. Fifty-eight and sixty-two patients scheduled to receive highly emetogenic chemotherapy (HEC and moderately emetogenic chemotherapy (MEC, respectively, were randomized 1:1 to receive either standard antiemetic therapy in accordance with international guidelines (S group or standard antiemetic therapy plus oral rikkunshito (R group. The primary endpoint was overall complete response (CR—that is, no emesis and rescue medication in the first 120 h post-chemotherapy. Secondary endpoints included CR in the acute (0–24 h and delayed (>24–120 h phases and safety. Fifty-seven patients (S group, 28; R group, 29 receiving HEC and sixty-two patients (S group, 30; R group, 32 receiving MEC with comparable characteristics were evaluated. The CR rates were similar across the S and R groups for the HEC study in the overall (67.9% vs. 62.1%, acute (96.4% vs. 89.6%, and delayed (67.9% vs. 62.1% phases, respectively, and for the MEC study in the overall (83.3% vs. 84.4%, acute (100% vs. 100%, and delayed (83.3% vs. 84.4% phases, respectively. No severe adverse events were observed. Although rikkunshito was well tolerated, it did not demonstrate an additional preventative effect against CINV in lung cancer patients receiving HEC or MEC.Clinical Trial Registry Information: This study is registered with the University Hospital Medical Information Network (UMIN Clinical Trial Registry1, identification numbers UMIN 000014239 and UMIN 000014240.

Measurements of NN→dπ very near threshold. Pt. 2

International Nuclear Information System (INIS)

Korkmaz, E.; Li, Jin; Elliott, J.B.; Mack, D.J.; Rodning, N.L.; Hutcheon, D.A.; Abegg, R.; Greeniaus, L.G.; Miller, C.A.

1991-01-01

We have measured analyzing powers for the reaction pp→dπ + at beam energies 3 and 7 MeV above pion-production threshold. With the use of Watson's theorem to fix phases and effective range estimates of pion d-wave strength, we have been able to determine the NN→dπ s-wave amplitude and the major p-wave amplitude at these energies. The results are compared to the Faddeev model predictions of Blankleider. (orig.)

Safety, tolerability, and immunogenicity of the novel antituberculous vaccine RUTI: randomized, placebo-controlled phase II clinical trial in patients with latent tuberculosis infection.

Science.gov (United States)

Nell, Andre S; D'lom, Eva; Bouic, Patrick; Sabaté, Montserrat; Bosser, Ramon; Picas, Jordi; Amat, Mercè; Churchyard, Gavin; Cardona, Pere-Joan

2014-01-01

To evaluate the safety, tolerability and immunogenicity of three different doses (5, 25 and 50 µg) of the novel antituberculous vaccine RUTI compared to placebo in subjects with latent tuberculosis infection. Double-blind, randomized, placebo-controlled Phase II Clinical Trial (95 patients randomized). Three different RUTI doses and placebo were tested, randomized both in HIV-positive (n = 47) and HIV-negative subjects (n = 48), after completion of one month isoniazid (INH) pre-vaccination. Each subject received two vaccine administrations, 28 Days apart. Five patients withdrew and 90 patients completed the study. Assessment of safety showed no deaths during study. Two subjects had serious adverse events one had a retinal detachment while taking INH and was not randomized and the other had a severe local injection site abscess on each arm and was hospitalized; causality was assessed as very likely and by the end of the study the outcome had resolved. All the patients except 5 (21%) patients of the placebo group (3 HIV+ and 2 HIV-) reported at least one adverse event (AE) during the study. The most frequently occurring AEs among RUTI recipients were (% in HIV+/-): injection site reactions [erythema (91/92), induration (94/92), local nodules (46/25), local pain (66/75), sterile abscess (6/6), swelling (74/83), ulcer (20/11), headache (17/22) and nasopharyngitis (20/5)]. These events were mostly mild and well tolerated. Overall, a polyantigenic response was observed, which differed by HIV- status. The best polyantigenic response was obtained when administrating 25 µg RUTI, especially in HIV-positive subjects which was not increased after the second inoculation. This Phase II clinical trial demonstrates reasonable tolerability of RUTI. The immunogenicity profile of RUTI vaccine in LTBI subjects, even being variable among groups, allows us considering one single injection of one of the highest doses in future trials, preceded by an extended safety clinical

Fourier phasing with phase-uncertain mask

International Nuclear Information System (INIS)

Fannjiang, Albert; Liao, Wenjing

2013-01-01

Fourier phasing is the problem of retrieving Fourier phase information from Fourier intensity data. The standard Fourier phase retrieval (without a mask) is known to have many solutions which cause the standard phasing algorithms to stagnate and produce wrong or inaccurate solutions. In this paper Fourier phase retrieval is carried out with the introduction of a randomly fabricated mask in measurement and reconstruction. Highly probable uniqueness of solution, up to a global phase, was previously proved with exact knowledge of the mask. Here the uniqueness result is extended to the case where only rough information about the mask’s phases is assumed. The exponential probability bound for uniqueness is given in terms of the uncertainty-to-diversity ratio of the unknown mask. New phasing algorithms alternating between the object update and the mask update are systematically tested and demonstrated to have the capability of recovering both the object and the mask (within the object support) simultaneously, consistent with the uniqueness result. Phasing with a phase-uncertain mask is shown to be robust with respect to the correlation in the mask as well as the Gaussian and Poisson noises. (paper)

Self-consistent random phase approximation - application to systems of strongly correlated fermions

International Nuclear Information System (INIS)

Jemai, M.

2004-07-01

In the present thesis we have applied the self consistent random phase approximation (SCRPA) to the Hubbard model with a small number of sites (a chain of 2, 4, 6,... sites). Earlier SCRPA had produced very good results in other models like the pairing model of Richardson. It was therefore interesting to see what kind of results the method is able to produce in the case of a more complex model like the Hubbard model. To our great satisfaction the case of two sites with two electrons (half-filling) is solved exactly by the SCRPA. This may seem a little trivial but the fact is that other respectable approximations like 'GW' or the approach with the Gutzwiller wave function yield results still far from exact. With this promising starting point, the case of 6 sites at half filling was considered next. For that case, evidently, SCRPA does not any longer give exact results. However, they are still excellent for a wide range of values of the coupling constant U, covering for instance the phase transition region towards a state with non zero magnetisation. We consider this as a good success of the theory. Non the less the case of 4 sites (a plaquette), as indeed all cases with 4n sites at half filling, turned out to have a problem because of degeneracies at the Hartree Fock level. A generalisation of the present method, including in addition to the pairs, quadruples of Fermions operators (called second RPA) is proposed to also include exactly the plaquette case in our approach. This is therefore a very interesting perspective of the present work. (author)

Tensor hypercontracted ppRPA: Reducing the cost of the particle-particle random phase approximation from O(r {sup 6}) to O(r {sup 4})

Energy Technology Data Exchange (ETDEWEB)

Shenvi, Neil; Yang, Yang; Yang, Weitao [Department of Chemistry, Duke University, Durham, NC 27708 (United States); Aggelen, Helen van [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)

2014-07-14

In recent years, interest in the random-phase approximation (RPA) has grown rapidly. At the same time, tensor hypercontraction has emerged as an intriguing method to reduce the computational cost of electronic structure algorithms. In this paper, we combine the particle-particle random phase approximation with tensor hypercontraction to produce the tensor-hypercontracted particle-particle RPA (THC-ppRPA) algorithm. Unlike previous implementations of ppRPA which scale as O(r{sup 6}), the THC-ppRPA algorithm scales asymptotically as only O(r{sup 4}), albeit with a much larger prefactor than the traditional algorithm. We apply THC-ppRPA to several model systems and show that it yields the same results as traditional ppRPA to within mH accuracy. Our method opens the door to the development of post-Kohn Sham functionals based on ppRPA without the excessive asymptotic cost of traditional ppRPA implementations.

基于计算全息的串联式三随机相位板图像加密%Image encryption technology of three random phase based on computer generated hologram

Institute of Scientific and Technical Information of China (English)

席思星; 孙欣; 刘兵; 田巍; 云茂金; 孔伟金; 张文飞; 梁键

2011-01-01

本文提出一种串联式三随机相位板图像加密的新方法，该方法充分运用计算全息记录复值光场的特性以记录加密图像，在传统的双随机相位加密系统基础上，置人第三个随机相位板在输出平面上，对输出的计算全息图进行相位调制加密，引入了新的密钥，获得很好的双密钥效果!同时由于计算全息周再现的多频特性，解密须正确提取单元频谱，进一步提高了图像传输的安全性。%A new image encryption technology of three random phase plates is proposed.Recording the encrypted image by CGH with it＇s features of Recording the value of optical field in this method,the third random phase plate was placed on the output plane in the 4f double random phase encryption system to modulate and encrypt the phase of the CGH,there are new keys,the third random phase plate,the exact drawing of the spectrum uint with the multi-frequency characteristics of CGH,which further improve the image transmission security.

Bioengineered Temporomandibular Joint Disk Implants: Study Protocol for a Two-Phase Exploratory Randomized Preclinical Pilot Trial in 18 Black Merino Sheep (TEMPOJIMS)

Science.gov (United States)

Monje, Florencio Gil; González-García, Raúl; Little, Christopher B; Mónico, Lisete; Pinho, Mário; Santos, Fábio Abade; Carrapiço, Belmira; Gonçalves, Sandra Cavaco; Morouço, Pedro; Alves, Nuno; Moura, Carla; Wang, Yadong; Jeffries, Eric; Gao, Jin; Sousa, Rita; Neto, Lia Lucas; Caldeira, Daniel; Salvado, Francisco

2017-01-01

Background Preclinical trials are essential to test efficacious options to substitute the temporomandibular joint (TMJ) disk. The contemporary absence of an ideal treatment for patients with severe TMJ disorders can be related to difficulties concerning the appropriate study design to conduct preclinical trials in the TMJ field. These difficulties can be associated with the use of heterogeneous animal models, the use of the contralateral TMJ as control, the absence of rigorous randomized controlled preclinical trials with blinded outcomes assessors, and difficulties involving multidisciplinary teams. Objective This study aims to develop a new, reproducible, and effective study design for preclinical research in the TMJ domain, obtaining rigorous data related to (1) identify the impact of bilateral discectomy in black Merino sheep, (2) identify the impact of bilateral discopexy in black Merino sheep, and (3) identify the impact of three different bioengineering TMJ discs in black Merino sheep. Methods A two-phase exploratory randomized controlled preclinical trial with blinded outcomes is proposed. In the first phase, nine sheep are randomized into three different surgical bilateral procedures: bilateral discectomy, bilateral discopexy, and sham surgery. In the second phase, nine sheep are randomized to bilaterally test three different TMJ bioengineering disk implants. The primary outcome is the histological gradation of TMJ. Secondary outcomes are imaging changes, absolute masticatory time, ruminant time per cycle, ruminant kinetics, ruminant area, and sheep weight. Results Previous preclinical studies in this field have used the contralateral unoperated side as a control, different animal models ranging from mice to a canine model, with nonrandomized, nonblinded and uncontrolled study designs and limited outcomes measures. The main goal of this exploratory preclinical protocol is to set a new standard for future preclinical trials in oromaxillofacial surgery

Communication: An effective linear-scaling atomic-orbital reformulation of the random-phase approximation using a contracted double-Laplace transformation

International Nuclear Information System (INIS)

Schurkus, Henry F.; Ochsenfeld, Christian

2016-01-01

An atomic-orbital (AO) reformulation of the random-phase approximation (RPA) correlation energy is presented allowing to reduce the steep computational scaling to linear, so that large systems can be studied on simple desktop computers with fully numerically controlled accuracy. Our AO-RPA formulation introduces a contracted double-Laplace transform and employs the overlap-metric resolution-of-the-identity. First timings of our pilot code illustrate the reduced scaling with systems comprising up to 1262 atoms and 10 090 basis functions. 

Random walks, random fields, and disordered systems

CERN Document Server

Černý, Jiří; Kotecký, Roman

2015-01-01

Focusing on the mathematics that lies at the intersection of probability theory, statistical physics, combinatorics and computer science, this volume collects together lecture notes on recent developments in the area. The common ground of these subjects is perhaps best described by the three terms in the title: Random Walks, Random Fields and Disordered Systems. The specific topics covered include a study of Branching Brownian Motion from the perspective of disordered (spin-glass) systems, a detailed analysis of weakly self-avoiding random walks in four spatial dimensions via methods of field theory and the renormalization group, a study of phase transitions in disordered discrete structures using a rigorous version of the cavity method, a survey of recent work on interacting polymers in the ballisticity regime and, finally, a treatise on two-dimensional loop-soup models and their connection to conformally invariant systems and the Gaussian Free Field. The notes are aimed at early graduate students with a mod...

Multiple-image authentication with a cascaded multilevel architecture based on amplitude field random sampling and phase information multiplexing.

Science.gov (United States)

Fan, Desheng; Meng, Xiangfeng; Wang, Yurong; Yang, Xiulun; Pan, Xuemei; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

2015-04-10

A multiple-image authentication method with a cascaded multilevel architecture in the Fresnel domain is proposed, in which a synthetic encoded complex amplitude is first fabricated, and its real amplitude component is generated by iterative amplitude encoding, random sampling, and space multiplexing for the low-level certification images, while the phase component of the synthetic encoded complex amplitude is constructed by iterative phase information encoding and multiplexing for the high-level certification images. Then the synthetic encoded complex amplitude is iteratively encoded into two phase-type ciphertexts located in two different transform planes. During high-level authentication, when the two phase-type ciphertexts and the high-level decryption key are presented to the system and then the Fresnel transform is carried out, a meaningful image with good quality and a high correlation coefficient with the original certification image can be recovered in the output plane. Similar to the procedure of high-level authentication, in the case of low-level authentication with the aid of a low-level decryption key, no significant or meaningful information is retrieved, but it can result in a remarkable peak output in the nonlinear correlation coefficient of the output image and the corresponding original certification image. Therefore, the method realizes different levels of accessibility to the original certification image for different authority levels with the same cascaded multilevel architecture.

Selumetinib in Combination With Dacarbazine in Patients With Metastatic Uveal Melanoma: A Phase III, Multicenter, Randomized Trial (SUMIT).

Science.gov (United States)

Carvajal, Richard D; Piperno-Neumann, Sophie; Kapiteijn, Ellen; Chapman, Paul B; Frank, Stephen; Joshua, Anthony M; Piulats, Josep M; Wolter, Pascal; Cocquyt, Veronique; Chmielowski, Bartosz; Evans, T R Jeffry; Gastaud, Lauris; Linette, Gerald; Berking, Carola; Schachter, Jacob; Rodrigues, Manuel J; Shoushtari, Alexander N; Clemett, Delyth; Ghiorghiu, Dana; Mariani, Gabriella; Spratt, Shirley; Lovick, Susan; Barker, Peter; Kilgour, Elaine; Lai, Zhongwu; Schwartz, Gary K; Nathan, Paul

2018-04-20

Purpose Uveal melanoma is the most common primary intraocular malignancy in adults with no effective systemic treatment option in the metastatic setting. Selumetinib (AZD6244, ARRY-142886) is an oral, potent, and selective MEK1/2 inhibitor with a short half-life, which demonstrated single-agent activity in patients with metastatic uveal melanoma in a randomized phase II trial. Methods The Selumetinib (AZD6244: ARRY-142886) (Hyd-Sulfate) in Metastatic Uveal Melanoma (SUMIT) study was a phase III, double-blind trial ( ClinicalTrial.gov identifier: NCT01974752) in which patients with metastatic uveal melanoma and no prior systemic therapy were randomly assigned (3:1) to selumetinib (75 mg twice daily) plus dacarbazine (1,000 mg/m 2 intravenously on day 1 of every 21-day cycle) or placebo plus dacarbazine. The primary end point was progression-free survival (PFS) by blinded independent central radiologic review. Secondary end points included overall survival and objective response rate. Results A total of 129 patients were randomly assigned to receive selumetinib plus dacarbazine (n = 97) or placebo plus dacarbazine (n = 32). In the selumetinib plus dacarbazine group, 82 patients (85%) experienced a PFS event, compared with 24 (75%) in the placebo plus dacarbazine group (median, 2.8 v 1.8 months); the hazard ratio for PFS was 0.78 (95% CI, 0.48 to 1.27; two-sided P = .32). The objective response rate was 3% with selumetinib plus dacarbazine and 0% with placebo plus dacarbazine (two-sided P = .36). At 37% maturity (n = 48 deaths), analysis of overall survival gave a hazard ratio of 0.75 (95% CI, 0.39 to 1.46; two-sided P = .40). The most frequently reported adverse events (selumetinib plus dacarbazine v placebo plus dacarbazine) were nausea (62% v 19%), rash (57% v 6%), fatigue (44% v 47%), diarrhea (44% v 22%), and peripheral edema (43% v 6%). Conclusion In patients with metastatic uveal melanoma, the combination of selumetinib plus dacarbazine had a tolerable safety

Random scalar fields and hyperuniformity

Science.gov (United States)

Ma, Zheng; Torquato, Salvatore

2017-06-01

Disordered many-particle hyperuniform systems are exotic amorphous states of matter that lie between crystals and liquids. Hyperuniform systems have attracted recent attention because they are endowed with novel transport and optical properties. Recently, the hyperuniformity concept has been generalized to characterize two-phase media, scalar fields, and random vector fields. In this paper, we devise methods to explicitly construct hyperuniform scalar fields. Specifically, we analyze spatial patterns generated from Gaussian random fields, which have been used to model the microwave background radiation and heterogeneous materials, the Cahn-Hilliard equation for spinodal decomposition, and Swift-Hohenberg equations that have been used to model emergent pattern formation, including Rayleigh-Bénard convection. We show that the Gaussian random scalar fields can be constructed to be hyperuniform. We also numerically study the time evolution of spinodal decomposition patterns and demonstrate that they are hyperuniform in the scaling regime. Moreover, we find that labyrinth-like patterns generated by the Swift-Hohenberg equation are effectively hyperuniform. We show that thresholding (level-cutting) a hyperuniform Gaussian random field to produce a two-phase random medium tends to destroy the hyperuniformity of the progenitor scalar field. We then propose guidelines to achieve effectively hyperuniform two-phase media derived from thresholded non-Gaussian fields. Our investigation paves the way for new research directions to characterize the large-structure spatial patterns that arise in physics, chemistry, biology, and ecology. Moreover, our theoretical results are expected to guide experimentalists to synthesize new classes of hyperuniform materials with novel physical properties via coarsening processes and using state-of-the-art techniques, such as stereolithography and 3D printing.

Phase transitions in random uniaxial systems with dipolar interactions

International Nuclear Information System (INIS)

Schuster, H.G.

1977-01-01

The critical behaviour of random uniaxial ferromagnetic (ferroelectric) systems with both short range and long range dipolar interactions is investigated, using the field theoretic renormalization method of Brezin et al. for the free energy above and below transition point Tsub(c). The randomness is due to externally introduced fluctuations in the short range interactions (quenched case) or (and) magneto-elastic coupling to the lattice (annealed case). Strong deviations in the critical behaviour with respect to the pure systems are found. In the quenched case, e.g., the specific heat C and the coefficient f 2 (of M 3 in the equation of state, where M is the magnetization) change from C proportional to abs ln abs t abs abssup(1/3), f 2 proportional to abs ln abs t abs abs sup(1/3), f 2 proportional to abs ln abs t abs abs -1 in the pure system to C = A+- + C+-exp[-4√ 3 106 abs ln abs t abs abs], f 2 proportional to abs ln abs t abs abs sup(-1/2) (where t = (T-Tsub(c)) / Tsub(c) is the reduced temperature and A+-, C+- are constants) in the random situation. (orig.) [de

Vanishing-Overhead Linear-Scaling Random Phase Approximation by Cholesky Decomposition and an Attenuated Coulomb-Metric.

Science.gov (United States)

Luenser, Arne; Schurkus, Henry F; Ochsenfeld, Christian

2017-04-11

A reformulation of the random phase approximation within the resolution-of-the-identity (RI) scheme is presented, that is competitive to canonical molecular orbital RI-RPA already for small- to medium-sized molecules. For electronically sparse systems drastic speedups due to the reduced scaling behavior compared to the molecular orbital formulation are demonstrated. Our reformulation is based on two ideas, which are independently useful: First, a Cholesky decomposition of density matrices that reduces the scaling with basis set size for a fixed-size molecule by one order, leading to massive performance improvements. Second, replacement of the overlap RI metric used in the original AO-RPA by an attenuated Coulomb metric. Accuracy is significantly improved compared to the overlap metric, while locality and sparsity of the integrals are retained, as is the effective linear scaling behavior.

Extending the random-phase approximation for electronic correlation energies: the renormalized adiabatic local density approximation

DEFF Research Database (Denmark)

Olsen, Thomas; Thygesen, Kristian S.

2012-01-01

The adiabatic connection fluctuation-dissipation theorem with the random phase approximation (RPA) has recently been applied with success to obtain correlation energies of a variety of chemical and solid state systems. The main merit of this approach is the improved description of dispersive forces...... while chemical bond strengths and absolute correlation energies are systematically underestimated. In this work we extend the RPA by including a parameter-free renormalized version of the adiabatic local-density (ALDA) exchange-correlation kernel. The renormalization consists of a (local) truncation...... of the ALDA kernel for wave vectors q > 2kF, which is found to yield excellent results for the homogeneous electron gas. In addition, the kernel significantly improves both the absolute correlation energies and atomization energies of small molecules over RPA and ALDA. The renormalization can...

Approximate Coulomb effects in the three-body scattering problem

International Nuclear Information System (INIS)

Haftel, M.I.; Zankel, H.

1981-01-01

From the momentum space Faddeev equations we derive approximate expressions which describe the Coulomb-nuclear interference in the three-body elastic scattering, rearrangement, and breakup problems and apply the formalism to p-d elastic scattering. The approximations treat the Coulomb interference as mainly a two-body effect, but we allow for the charge distribution of the deuteron in the p-d calculations. Real and imaginary parts of the Coulomb correction to the elastic scattering phase shifts are described in terms of on-shell quantities only. In the case of pure Coulomb breakup we recover the distorted-wave Born approximation result. Comparing the derived approximation with the full Faddeev p-d elastic scattering calculation, which includes the Coulomb force, we obtain good qualitative agreement in S and P waves, but disagreement in repulsive higher partial waves. The on-shell approximation investigated is found to be superior to other current approximations. The calculated differential cross sections at 10 MeV raise the question of whether there is a significant Coulomb-nuclear interference at backward angles

Nucleon form factors at high q2 within constituent quark models

International Nuclear Information System (INIS)

Desplanques, B.; Silvestre-Brac, B.; Cano, F.; Noguera, S.; Gonzalez, P.; .

2000-01-01

The nucleon form factors are calculated using a non-relativistic description in terms of constituent quarks. The emphasis is put on present numerical methods used to solve the three-body problem in order to reliably predict the expected asymptotic behavior of form factors. Nucleon wave functions obtained in the hyperspherical formalism or employing Faddeev equations have been considered. While a q -8 behavior is expected at high q for a quark-quark force behaving like 1/r at short distances, it is found that the hyper central approximation in the hyperspherical formalism (K = 0) leads to a q -7 behavior. An infinite set of waves would be required to get the correct behavior. Solutions of the Faddeev equations lead to the q -8 behavior. The coefficient of the corresponding term, however, depends on the number of partial waves retained in the Faddeev amplitude. The convergence to the asymptotic behavior has also been studied. Approximate expressions characterizing this one have been derived. From the comparison with the most complete Faddeev calculation, a validity range is inferred for restricted calculations. Refs. 46 (author)

Continuum gauge theories

International Nuclear Information System (INIS)

Stora, R.

1976-09-01

The mathematics of gauge fields and some related concepts are discussed: some corrections on the principal fiber bundles emphasize the idea that the present formulation of continuum theories is incomplete. The main ingredients used through the construction of the renormalized perturbation series are then described: the Faddeev Popov argument, and the Faddeev Popov Lagrangian; the Slavnov symmetry and the nature of the Faddeev Popov ghost fields; the Slavnov identity, with an obstruction: the Adler Bardeen anomaly, and its generalization to the local cohomology of the gauge Lie algebra. Some smooth classical configurations of gauge fields which ought to play a prominent role in the evaluation of the functional integral describing the theory are also reviewed

Uniformity transition for ray intensities in random media

Science.gov (United States)

Pradas, Marc; Pumir, Alain; Wilkinson, Michael

2018-04-01

This paper analyses a model for the intensity of distribution for rays propagating without absorption in a random medium. The random medium is modelled as a dynamical map. After N iterations, the intensity is modelled as a sum S of {{\\mathcal N}} contributions from different trajectories, each of which is a product of N independent identically distributed random variables x k , representing successive focussing or de-focussing events. The number of ray trajectories reaching a given point is assumed to proliferate exponentially: {{\\mathcal N}}=ΛN , for some Λ>1 . We investigate the probability distribution of S. We find a phase transition as parameters of the model are varied. There is a phase where the fluctuations of S are suppressed as N\\to ∞ , and a phase where the S has large fluctuations, for which we provide a large deviation analysis.

Low-lying dipole response in the stable 40,48Ca nuclei within the second random-phase approximation

International Nuclear Information System (INIS)

Gambacurta, D.; Grasso, M.; Catara, F.

2012-01-01

The low-lying dipole strength distributions of 40 CaCa and 48 Ca, in the energy region between 5 and 10 MeV, are studied within the second random phase approximation (RPA) with Skyrme interaction. Standard RPA models do not usually predict any presence of strength in this energy region, while experimentally a significant amount of strength is found. The inclusion of the 2 particle −2 hole configurations allows to obtain a description in a rather good agreement with the experimental data. The properties of the most collective state are analyzed in terms of its 1 particle −1 hole nature and its transition densities.

Low-lying dipole response in the stable 40,48Ca nuclei within the second random-phase approximation

Science.gov (United States)

Gambacurta, D.; Grasso, M.; Catara, F.

2012-10-01

The low-lying dipole strength distributions of 40CaCa and 48Ca, in the energy region between 5 and 10 MeV, are studied within the second random phase approximation (RPA) with Skyrme interaction. Standard RPA models do not usually predict any presence of strength in this energy region, while experimentally a significant amount of strength is found. The inclusion of the 2 particle -2 hole configurations allows to obtain a description in a rather good agreement with the experimental data. The properties of the most collective state are analyzed in terms of its 1 particle -1 hole nature and its transition densities.

Roles of antinucleon degrees of freedom in the relativistic random phase approximation

Science.gov (United States)

Kurasawa, Haruki; Suzuki, Toshio

2015-11-01

The roles of antinucleon degrees of freedom in the relativistic random phase approximation (RPA) are investigated. The energy-weighted sum of the RPA transition strengths is expressed in terms of the double commutator between the excitation operator and the Hamiltonian, as in nonrelativistic models. The commutator, however, should not be calculated in the usual way in the local field theory, because, otherwise, the sum vanishes. The sum value obtained correctly from the commutator is infinite, owing to the Dirac sea. Most of the previous calculations take into account only some of the nucleon-antinucleon states, in order to avoid divergence problems. As a result, RPA states with negative excitation energy appear, which make the sum value vanish. Moreover, disregarding the divergence changes the sign of nuclear interactions in the RPA equation that describes the coupling of the nucleon particle-hole states with the nucleon-antinucleon states. Indeed, the excitation energies of the spurious state and giant monopole states in the no-sea approximation are dominated by these unphysical changes. The baryon current conservation can be described without touching the divergence problems. A schematic model with separable interactions is presented, which makes the structure of the relativistic RPA transparent.

Neuropsychiatric safety with liraglutide 3.0 mg for weight management: Results from randomized controlled phase 2 and 3a trials.

Science.gov (United States)

O'Neil, Patrick M; Aroda, Vanita R; Astrup, Arne; Kushner, Robert; Lau, David C W; Wadden, Thomas A; Brett, Jason; Cancino, Ana-Paula; Wilding, John P H

2017-11-01

Liraglutide, a GLP-1 receptor agonist, regulates appetite via receptors in the brain. Because of concerns regarding the potential of centrally-acting anti-obesity medications to affect mental health, pooled neuropsychiatric safety data from all phase 2 and 3a randomized, double-blind trials with liraglutide 3.0 mg were evaluated post hoc. Data from the liraglutide weight-management programme were pooled. Across trials, individuals with a body mass index ≥30 or ≥27 kg/m 2 with weight-related comorbidities were randomized to once-daily subcutaneous liraglutide 3.0 mg (n = 3384) or placebo (n = 1941), both with a 500 kcal/d deficit diet, plus exercise. Adverse events related to neuropsychiatric safety were collected in all trials. Additionally, in the phase 3a trials, validated mental-health questionnaires were prospectively and systematically administered. In the pooled analysis of 5325 randomized and exposed individuals, rates of depression (2.1 vs 2.1 events/100 person-years) and anxiety (1.9 vs 1.7 events/100 person-years) through adverse event reporting were similarly low in liraglutide and placebo groups. Nine (0.3%) individuals receiving liraglutide and 2 (0.1%) receiving placebo reported adverse events of suicidal ideation or behaviour. In phase 3a trials, mean baseline Patient Health Questionnaire-9 scores of 2.8 ± 3.0 vs 2.9 ± 3.1 for liraglutide vs placebo improved to 1.8 ± 2.7 vs 1.9 ± 2.7, respectively, at treatment end; 34/3291 individuals (1.0%) receiving liraglutide 3.0 mg vs 19/1843 (1.0%) receiving placebo reported suicidal ideation on the Columbia-Suicide Severity Rating Scale. Results of this exploratory pooled analysis provide no cause for concern regarding the neuropsychiatric safety of treatment with liraglutide 3.0 mg in patients similar to those included in the examined trials. Although there was a small numerical imbalance in suicidal ideation with liraglutide through adverse event reporting, no

Differential benefits of amoxicillin-metronidazole in different phases of periodontal therapy in a randomized controlled crossover clinical trial.

Science.gov (United States)

Mombelli, Andrea; Almaghlouth, Adnan; Cionca, Norbert; Courvoisier, Delphine S; Giannopoulou, Catherine

2015-03-01

The specific advantage of administering systemic antibiotics during initial, non-surgical therapy or in the context of periodontal surgery is unclear. This study assesses the differential outcomes of periodontal therapy supplemented with amoxicillin-metronidazole during either the non-surgical or the surgical treatment phase. This is a single-center, randomized placebo-controlled crossover clinical trial with a 1-year follow-up. Eighty participants with Aggregatibacter actinomycetemcomitans-associated moderate to advanced periodontitis were randomized into two treatment groups: group A, antibiotics (500 mg metronidazole plus 375 mg amoxicillin three times per day for 7 days) during the first, non-surgical phase of periodontal therapy (T1) and placebo during the second, surgical phase (T2); and group B, placebo during T1 and antibiotics during T2. The number of sites with probing depth (PD) >4 mm and bleeding on probing (BOP) per patient was the primary outcome. A total of 11,212 sites were clinically monitored on 1,870 teeth. T1 with antibiotics decreased the number of sites with PD >4 mm and BOP per patient significantly more than without (group A: from 34.5 to 5.7, 84%; group B: from 28.7 to 8.7, 70%; P antibiotics, but only eight treated with placebo, achieved a 10-fold reduction of diseased sites (P = 0.007). Consequently, fewer patients of group A needed additional therapy, the mean number of surgical interventions was lower, and treatment time in T2 was shorter. Six months after T2, the mean number of residual pockets (group A: 2.8 ± 5.2; group B: 2.2 ± 5.0) was not significantly different and was sustained over 12 months in both groups. Giving the antibiotics during T1 or T2 yielded similar long-term outcomes, but antibiotics in T1 resolved the disease quicker and thus reduced the need for additional surgical intervention.

Randomized placebo-controlled phase II trial of autologous mesenchymal stem cells in multiple sclerosis.

Directory of Open Access Journals (Sweden)

Sara Llufriu

Full Text Available Uncontrolled studies of mesenchymal stem cells (MSCs in multiple sclerosis suggested some beneficial effect. In this randomized, double-blind, placebo-controlled, crossover phase II study we investigated their safety and efficacy in relapsing-remitting multiple sclerosis patients. Efficacy was evaluated in terms of cumulative number of gadolinium-enhancing lesions (GEL on magnetic resonance imaging (MRI at 6 months and at the end of the study.Patients unresponsive to conventional therapy, defined by at least 1 relapse and/or GEL on MRI scan in past 12 months, disease duration 2 to 10 years and Expanded Disability Status Scale (EDSS 3.0-6.5 were randomized to receive IV 1-2×10(6 bone-marrow-derived-MSCs/Kg or placebo. After 6 months, the treatment was reversed and patients were followed-up for another 6 months. Secondary endpoints were clinical outcomes (relapses and disability by EDSS and MS Functional Composite, and several brain MRI and optical coherence tomography measures. Immunological tests were explored to assess the immunomodulatory effects.At baseline 9 patients were randomized to receive MSCs (n = 5 or placebo (n = 4. One patient on placebo withdrew after having 3 relapses in the first 5 months. We did not identify any serious adverse events. At 6 months, patients treated with MSCs had a trend to lower mean cumulative number of GEL (3.1, 95% CI = 1.1-8.8 vs 12.3, 95% CI = 4.4-34.5, p = 0.064, and at the end of study to reduced mean GEL (-2.8±5.9 vs 3±5.4, p = 0.075. No significant treatment differences were detected in the secondary endpoints. We observed a non-significant decrease of the frequency of Th1 (CD4+ IFN-γ+ cells in blood of MSCs treated patients.Bone-marrow-MSCs are safe and may reduce inflammatory MRI parameters supporting their immunomodulatory properties. ClinicalTrials.gov NCT01228266.

The potts chain in a random field: an exact solution

International Nuclear Information System (INIS)

Riera, R.; Chaves, C.M.G.F.; Santos, Raimundo R. dos.

1984-01-01

An exact solution is presented for the one-dimensional q-state Potts model in a quenched random field. The ferromagnetic phase is unstable against any small random field perturbation. The correlation function and the Edwards-Anderson order parameter Q are discussed. For finite q only the phase with Q ≠ 0 is present. (Author) [pt

Safety and immunogenicity of three different formulations of an adjuvanted varicella-zoster virus subunit candidate vaccine in older adults: a phase II, randomized, controlled study

NARCIS (Netherlands)

Chlibek, Roman; Smetana, Jan; Pauksens, Karlis; Rombo, Lars; van den Hoek, J. Anneke R.; Richardus, Jan H.; Plassmann, Georg; Schwarz, Tino F.; Ledent, Edouard; Heineman, Thomas C.

2014-01-01

This study investigated the safety and immunogenicity of different formulations and schedules of a candidate subunit herpes zoster vaccine containing varicella-zoster virus glycoprotein E (gE) with or without the adjuvant system AS01B. In this phase II, single-blind, randomized, controlled study,

Random-phase-approximation approach to optical and magnetic excitations in the two-dimensional multiband Hubbard model

International Nuclear Information System (INIS)

Yonemitsu, K.; Bishop, A.R.

1992-01-01

As a convenient qualitative approach to strongly correlated electronic systems, an inhomogeneous Hartree-Fock plus random-phase approximation is applied to response functions for the two-dimensional multiband Hubbard model for cuprate superconductors. A comparison of the results with those obtained by exact diagonalization by Wagner, Hanke, and Scalapino [Phys. Rev. B 43, 10 517 (1991)] shows that overall structures in optical and magnetic particle-hole excitation spectra are well reproduced by this method. This approach is computationally simple, retains conceptual clarity, and can be calibrated by comparison with exact results on small systems. Most importantly, it is easily extended to larger systems and straightforward to incorporate additional terms in the Hamiltonian, such as electron-phonon interactions, which may play a crucial role in high-temperature superconductivity

LETTER TO THE EDITOR: Phase transition in a random fragmentation problem with applications to computer science

Science.gov (United States)

Dean, David S.; Majumdar, Satya N.

2002-08-01

We study a fragmentation problem where an initial object of size x is broken into m random pieces provided x > x0 where x0 is an atomic cut-off. Subsequently, the fragmentation process continues for each of those daughter pieces whose sizes are bigger than x0. The process stops when all the fragments have sizes smaller than x0. We show that the fluctuation of the total number of splitting events, characterized by the variance, generically undergoes a nontrivial phase transition as one tunes the branching number m through a critical value m = mc. For m mc they are anomalously large and non-Gaussian. We apply this general result to analyse two different search algorithms in computer science.

Inclusive charged-current neutrino-nucleus reactions calculated with the relativistic quasiparticle random-phase approximation

International Nuclear Information System (INIS)

Paar, N.; Vretenar, D.; Marketin, T.; Ring, P.

2008-01-01

Inclusive neutrino-nucleus cross sections are calculated using a consistent relativistic mean-field theoretical framework. The weak lepton-hadron interaction is expressed in the standard current-current form, the nuclear ground state is described with the relativistic Hartree-Bogoliubov model, and the relevant transitions to excited nuclear states are calculated in the relativistic quasiparticle random-phase approximation. Illustrative test calculations are performed for charged-current neutrino reactions on 12 C, 16 O, 56 Fe, and 208 Pb, and results compared with previous studies and available data. Through the use of the experimental neutrino fluxes, the averaged cross sections are evaluated for nuclei of interest for neutrino detectors. We analyze the total neutrino-nucleus cross sections and the evolution of the contribution of the different multipole excitations as a function of neutrino energy. The cross sections for reactions of supernova neutrinos on 16 O and 208 Pb target nuclei are analyzed as functions of the temperature and chemical potential

Randomized phase III trial of regorafenib in metastatic colorectal cancer: analysis of the CORRECT Japanese and non-Japanese subpopulations.

Science.gov (United States)

Yoshino, Takayuki; Komatsu, Yoshito; Yamada, Yasuhide; Yamazaki, Kentaro; Tsuji, Akihito; Ura, Takashi; Grothey, Axel; Van Cutsem, Eric; Wagner, Andrea; Cihon, Frank; Hamada, Yoko; Ohtsu, Atsushi

2015-06-01

In the international, phase III, randomized, double-blind CORRECT trial, regorafenib significantly prolonged overall survival (OS) versus placebo in patients with metastatic colorectal cancer (mCRC) that had progressed on all standard therapies. This post hoc analysis evaluated the efficacy and safety of regorafenib in Japanese and non-Japanese subpopulations in the CORRECT trial. Patients were randomized 2 : 1 to regorafenib 160 mg once daily or placebo for weeks 1-3 of each 4-week cycle. The primary endpoint was OS. Outcomes were assessed using descriptive statistics. One hundred Japanese and 660 non-Japanese patients were randomized to regorafenib (n = 67 and n = 438) or placebo (n = 33 and n = 222). Regorafenib had a consistent OS benefit in the Japanese and non-Japanese subpopulations, with hazard ratios of 0.81 (95 % confidence interval [CI] 0.43-1.51) and 0.77 (95 % CI 0.62-0.94), respectively. Regorafenib-associated hand-foot skin reaction, hypertension, proteinuria, thrombocytopenia, and lipase elevations occurred more frequently in the Japanese subpopulation than in the non-Japanese subpopulation, but were generally manageable. Regorafenib appears to have comparable efficacy in Japanese and non-Japanese subpopulations, with a manageable adverse-event profile, suggesting that this agent could potentially become a standard of care in patients with mCRC.

Beyond the random-phase approximation for the electron correlation energy: the importance of single excitations.

Science.gov (United States)

Ren, Xinguo; Tkatchenko, Alexandre; Rinke, Patrick; Scheffler, Matthias

2011-04-15

The random-phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange (EX) energy, represents the state-of-the-art exchange-correlation functional within density-functional theory. However, the standard RPA practice--evaluating both the EX and the RPA correlation energies using Kohn-Sham (KS) orbitals from local or semilocal exchange-correlation functionals--leads to a systematic underbinding of molecules and solids. Here we demonstrate that this behavior can be corrected by adding a "single excitation" contribution, so far not included in the standard RPA scheme. A similar improvement can also be achieved by replacing the non-self-consistent EX total energy by the corresponding self-consistent Hartree-Fock total energy, while retaining the RPA correlation energy evaluated using KS orbitals. Both schemes achieve chemical accuracy for a standard benchmark set of noncovalent intermolecular interactions.

Rocksalt or cesium chloride: Investigating the relative stability of the cesium halide structures with random phase approximation based methods

Science.gov (United States)

Nepal, Niraj K.; Ruzsinszky, Adrienn; Bates, Jefferson E.

2018-03-01

The ground state structural and energetic properties for rocksalt and cesium chloride phases of the cesium halides were explored using the random phase approximation (RPA) and beyond-RPA methods to benchmark the nonempirical SCAN meta-GGA and its empirical dispersion corrections. The importance of nonadditivity and higher-order multipole moments of dispersion in these systems is discussed. RPA generally predicts the equilibrium volume for these halides within 2.4% of the experimental value, while beyond-RPA methods utilizing the renormalized adiabatic LDA (rALDA) exchange-correlation kernel are typically within 1.8%. The zero-point vibrational energy is small and shows that the stability of these halides is purely due to electronic correlation effects. The rAPBE kernel as a correction to RPA overestimates the equilibrium volume and could not predict the correct phase ordering in the case of cesium chloride, while the rALDA kernel consistently predicted results in agreement with the experiment for all of the halides. However, due to its reasonable accuracy with lower computational cost, SCAN+rVV10 proved to be a good alternative to the RPA-like methods for describing the properties of these ionic solids.

Phase II prospective randomized trial of weight loss prior to radical prostatectomy.

Science.gov (United States)

Henning, Susanne M; Galet, Colette; Gollapudi, Kiran; Byrd, Joshua B; Liang, Pei; Li, Zhaoping; Grogan, Tristan; Elashoff, David; Magyar, Clara E; Said, Jonathan; Cohen, Pinchas; Aronson, William J

2017-12-04

Obesity is associated with poorly differentiated and advanced prostate cancer and increased mortality. In preclinical models, caloric restriction delays prostate cancer progression and prolongs survival. We sought to determine if weight loss (WL) in men with prostate cancer prior to radical prostatectomy affects tumor apoptosis and proliferation, and if WL effects other metabolic biomarkers. In this Phase II prospective trial, overweight and obese men scheduled for radical prostatectomy were randomized to a 5-8 week WL program consisting of standard structured energy-restricted meal plans (1200-1500 Kcal/day) and physical activity or to a control group. The primary endpoint was apoptotic index in the radical prostatectomy malignant epithelium. Secondary endpoints were proliferation (Ki67) in the radical prostatectomy tissue, body weight, body mass index (BMI), waist to hip ratio, body composition, and serum PSA, insulin, triglyceride, cholesterol, testosterone, estradiol, leptin, adiponectin, interleukin 6, interleukin 8, insulin-like growth factor 1, and IGF binding protein 1. In total 23 patients were randomized to the WL intervention and 21 patients to the control group. Subjects in the intervention group had significantly more weight loss (WL:-3.7 ± 0.5 kg; Control:-1.6 ± 0.5 kg; p = 0.007) than the control group and total fat mass was significantly reduced (WL:-2.1 ± 0.4; Control: 0.1 ± 0.3; p = 0.015). There was no significant difference in apoptotic or proliferation index between the groups. Among the other biomarkers, triglyceride, and insulin levels were significantly decreased in the WL compared with the control group. In summary, this short-term WL program prior to radical prostatectomy resulted in significantly more WL in the intervention vs. the control group and was accompanied by significant reductions in body fat mass, circulating triglycerides, and insulin. However, no significant changes were observed in malignant

High-K precession modes: Axially symmetric limit of wobbling motion in the cranked random-phase approximation description

International Nuclear Information System (INIS)

Shimizu, Yoshifumi R.; Matsuzaki, Masayuki; Matsuyanagi, Kenichi

2005-01-01

The rotational band built on the high-K multi-quasiparticle state can be interpreted as a multi-phonon band of the precession mode, which represents the precessional rotation about the axis perpendicular to the direction of the intrinsic angular momentum. By using the axially symmetric limit of the random-phase approximation (RPA) formalism developed for the nuclear wobbling motion, we study the properties of the precession modes in 178 W: the excitation energies, B(E2) and B(M1) values. We show that the excitations of such a specific type of rotation can be well described by the RPA formalism, which gives new insight into the wobbling motion in the triaxial superdeformed nuclei from a microscopic viewpoint

Everolimus for Previously Treated Advanced Gastric Cancer: Results of the Randomized, Double-Blind, Phase III GRANITE-1 Study

Science.gov (United States)

Ohtsu, Atsushi; Ajani, Jaffer A.; Bai, Yu-Xian; Bang, Yung-Jue; Chung, Hyun-Cheol; Pan, Hong-Ming; Sahmoud, Tarek; Shen, Lin; Yeh, Kun-Huei; Chin, Keisho; Muro, Kei; Kim, Yeul Hong; Ferry, David; Tebbutt, Niall C.; Al-Batran, Salah-Eddin; Smith, Heind; Costantini, Chiara; Rizvi, Syed; Lebwohl, David; Van Cutsem, Eric

2013-01-01

Purpose The oral mammalian target of rapamycin inhibitor everolimus demonstrated promising efficacy in a phase II study of pretreated advanced gastric cancer. This international, double-blind, phase III study compared everolimus efficacy and safety with that of best supportive care (BSC) in previously treated advanced gastric cancer. Patients and Methods Patients with advanced gastric cancer that progressed after one or two lines of systemic chemotherapy were randomly assigned to everolimus 10 mg/d (assignment schedule: 2:1) or matching placebo, both given with BSC. Randomization was stratified by previous chemotherapy lines (one v two) and region (Asia v rest of the world [ROW]). Treatment continued until disease progression or intolerable toxicity. Primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS), overall response rate, and safety. Results Six hundred fifty-six patients (median age, 62.0 years; 73.6% male) were enrolled. Median OS was 5.4 months with everolimus and 4.3 months with placebo (hazard ratio, 0.90; 95% CI, 0.75 to 1.08; P = .124). Median PFS was 1.7 months and 1.4 months in the everolimus and placebo arms, respectively (hazard ratio, 0.66; 95% CI, 0.56 to 0.78). Common grade 3/4 adverse events included anemia, decreased appetite, and fatigue. The safety profile was similar in patients enrolled in Asia versus ROW. Conclusion Compared with BSC, everolimus did not significantly improve overall survival for advanced gastric cancer that progressed after one or two lines of previous systemic chemotherapy. The safety profile observed for everolimus was consistent with that observed for everolimus in other cancers. PMID:24043745

Measurements on NN → dπ very near threshold. II

International Nuclear Information System (INIS)

Korkmaz, E.; Li, J.; Hutcheon, D.A.; Abegg, R.; Elliott, J.B.; Greeniaus, L.G.; Mack, D.J.; Miller, C.A.; Rodning, N.L.

1991-04-01

We have measured analyzing powers for the reaction pp → dπ + at beam energies 3 and 7 MeV above pion production threshold. With the use of Watson's Theorem to fix phases and effective range estimates of pion d-wave strength, we have been able to determine the NN → dπ s-wave amplitude and the two p-wave amplitudes at these energies. The results are compared to the Faddeev model predictions of Blankleider. (Author) 11 refs., 2 tabs., 11 figs

Application of phase-change materials in memory taxonomy.

Science.gov (United States)

Wang, Lei; Tu, Liang; Wen, Jing

2017-01-01

Phase-change materials are suitable for data storage because they exhibit reversible transitions between crystalline and amorphous states that have distinguishable electrical and optical properties. Consequently, these materials find applications in diverse memory devices ranging from conventional optical discs to emerging nanophotonic devices. Current research efforts are mostly devoted to phase-change random access memory, whereas the applications of phase-change materials in other types of memory devices are rarely reported. Here we review the physical principles of phase-change materials and devices aiming to help researchers understand the concept of phase-change memory. We classify phase-change memory devices into phase-change optical disc, phase-change scanning probe memory, phase-change random access memory, and phase-change nanophotonic device, according to their locations in memory hierarchy. For each device type we discuss the physical principles in conjunction with merits and weakness for data storage applications. We also outline state-of-the-art technologies and future prospects.

Low-lying dipole response in the stable {sup 40,48}Ca nuclei within the second random-phase approximation

Energy Technology Data Exchange (ETDEWEB)

Gambacurta, D.; Grasso, M.; Catara, F. [GANIL,CEA/DSM-CNRS/IN2P3, Caen (France); Institut de Physique Nucleaire, Universite Paris-Sud, IN2P3-CNRS, F-91406 Orsay Cedex (France); Dipartimento di Fisica e Astronomia dell' Universita di and INFN Catania (Italy)

2012-10-20

The low-lying dipole strength distributions of {sup 40}CaCa and {sup 48}Ca, in the energy region between 5 and 10 MeV, are studied within the second random phase approximation (RPA) with Skyrme interaction. Standard RPA models do not usually predict any presence of strength in this energy region, while experimentally a significant amount of strength is found. The inclusion of the 2 particle -2 hole configurations allows to obtain a description in a rather good agreement with the experimental data. The properties of the most collective state are analyzed in terms of its 1 particle -1 hole nature and its transition densities.

Long-Term Improvements After Multimodal Rehabilitation in Late Phase After Stroke: A Randomized Controlled Trial.

Science.gov (United States)

Bunketorp-Käll, Lina; Lundgren-Nilsson, Åsa; Samuelsson, Hans; Pekny, Tulen; Blomvé, Karin; Pekna, Marcela; Pekny, Milos; Blomstrand, Christian; Nilsson, Michael

2017-07-01

Treatments that improve function in late phase after stroke are urgently needed. We assessed whether multimodal interventions based on rhythm-and-music therapy or horse-riding therapy could lead to increased perceived recovery and functional improvement in a mixed population of individuals in late phase after stroke. Participants were assigned to rhythm-and-music therapy, horse-riding therapy, or control using concealed randomization, stratified with respect to sex and stroke laterality. Therapy was given twice a week for 12 weeks. The primary outcome was change in participants' perception of stroke recovery as assessed by the Stroke Impact Scale with an intention-to-treat analysis. Secondary objective outcome measures were changes in balance, gait, grip strength, and cognition. Blinded assessments were performed at baseline, postintervention, and at 3- and 6-month follow-up. One hundred twenty-three participants were assigned to rhythm-and-music therapy (n=41), horse-riding therapy (n=41), or control (n=41). Post-intervention, the perception of stroke recovery (mean change from baseline on a scale ranging from 1 to 100) was higher among rhythm-and-music therapy (5.2 [95% confidence interval, 0.79-9.61]) and horse-riding therapy participants (9.8 [95% confidence interval, 6.00-13.66]), compared with controls (-0.5 [-3.20 to 2.28]); P =0.001 (1-way ANOVA). The improvements were sustained in both intervention groups 6 months later, and corresponding gains were observed for the secondary outcomes. Multimodal interventions can improve long-term perception of recovery, as well as balance, gait, grip strength, and working memory in a mixed population of individuals in late phase after stroke. URL: http//www.ClinicalTrials.gov. Unique identifier: NCT01372059. © 2017 American Heart Association, Inc.

Correlation diagnostics of random spatially nonuniform optical fields

International Nuclear Information System (INIS)

Angel'skii, O.V.

1992-01-01

This review examines some questions concerning the capabilities of interference and polarization-interference correlation diagnostics of the amplitude-phase characteristics of random optical fields for the purpose of identifying these fields and then studying the corresponding objects. The diagnostics of random phase objects is discussed separately in the case in which the phase dispersion of the inhomogeneities is less than and greater than one. The outlook is promising for the use of the correlation dimensionality of chaos in a field as a diagnostic parameter. It is also shown that the use of interference principles for a parallel processing of large data files can substantially increase the speed of processing systems. 32 refs., 8 figs

A randomized phase 2 study of combination cediranib and olaparib versus olaparib alone as recurrence therapy in platinum-sensitive ovarian cancer

Science.gov (United States)

Liu, Joyce F.; Barry, William T.; Birrer, Michael; Lee, Jung-Min; Buckanovich, Ronald J.; Fleming, Gini F.; Rimel, BJ; Buss, Mary K.; Nattam, Sreenivasa; Hurteau, Jean; Luo, Weixiu; Quy, Philippa; Whalen, Christin; Obermayer, Lisa; Lee, Hang; Winer, Eric P.; Kohn, Elise C.; Ivy, S. Percy; Matulonis, Ursula A.

2015-01-01

Background Olaparib is an oral poly(ADP-ribose) polymerase inhibitor and cediranib is an oral anti-angiogenic with activity against VEGFR-1, 2, and 3. Both agents have antitumor activity in women with recurrent ovarian cancer, and the combination of these agents was active and had manageable toxicities in a Phase 1 trial. We asked whether the combination of cediranib and olaparib could improve progression-free survival compared to olaparib monotherapy in women with recurrent platinum-sensitive ovarian cancer. Methods We conducted a randomized, open-label, phase 2 study to evaluate the activity of olaparib monotherapy compared with combination cediranib and olaparib in women with ovarian cancer with measurable platinum-sensitive, relapsed, high-grade serous or endometrioid disease or those with deleterious germline BRCA1/2 mutations (gBRCAm). Patients were randomized using permuted blocks within stratum defined by gBRCA status and prior anti-angiogenic therapy to receive olaparib capsules 400mg twice daily or the combination at the recommended phase 2 dose of cediranib 30mg daily and olaparib capsules 200mg twice daily. The primary endpoint was progression-free survival (PFS) analyzed under intention to treat. The trial is registered with ClinicalTrials.gov, NCT01116648. The Phase 2 portion of the trial reported here is no longer accruing patients. Findings Forty-six of 90 randomized patients received olaparib alone, and 44 received cediranib/olaparib. Median PFS was significantly longer with cediranib/olaparib (17.7 vs. 9.0 mos, HR 0.42; p = 0.005). Grade 3 and 4 adverse events were more common with cediranib/olaparib, including fatigue (12 vs. 5), diarrhea (10 vs. 0), and hypertension (18 vs. 0). Subset analysis within stratum defined by BRCA1/2 status demonstrated activity of cediranib/olaparib in both gBRCAm and gBRCAwt/u (wild-type/unknown) patients. Significant improvement in PFS occurred in gBRCAwt/u women receiving cediranib/olaparib (16.5 vs. 5.7 mos, p = 0

Random phase plate hot spots and their effect on stimulated Brillouin backscatter and self-focusing

International Nuclear Information System (INIS)

Rose, H.A.

1995-01-01

Laser hot spots, as determined by Random Phase Plate (RPP) hot spots, control the critical value of the average intensity, I c , at which there is a rapid onset of stimulated scatter in the strongly damped convective regime of three wave parametric instabilities. For the case of stimulated Brillouin backscatter in a long scale length plasma, nascent hot spot ponderomotive self-focusing is shown to reduce the value of I c in the regime of very strongly damped acoustic waves. RPP hot spots have two, intrinsically nonlinear, thresholds for ponderomotive self-focusing. Large intensity amplifications occur in the hot spot neighborhood when the hot spot power exceeds a certain critical power, P c , which is independent of the optic's f number, F. When the second, F-dependent, hot spot power threshold is exceeded, a filament emerges from the far side of the hot spot, whose extent grows erratically in time

Design of the randomized, Phase III, QUAZAR AML Maintenance trial of CC-486 (oral azacitidine) maintenance therapy in acute myeloid leukemia.

Science.gov (United States)

Roboz, Gail J; Montesinos, Pau; Selleslag, Dominik; Wei, Andrew; Jang, Jun-Ho; Falantes, Jose; Voso, Maria T; Sayar, Hamid; Porkka, Kimmo; Marlton, Paula; Almeida, Antonio; Mohan, Sanjay; Ravandi, Farhad; Garcia-Manero, Guillermo; Skikne, Barry; Kantarjian, Hagop

2016-02-01

Older patients with acute myeloid leukemia (AML) have worse rates of complete remission and shorter overall survival than younger patients. The epigenetic modifier CC-486 is an oral formulation of azacitidine with promising clinical activity in patients with AML in Phase I studies. The Phase III, randomized, double-blind, placebo-controlled QUAZAR AML Maintenance trial (CC-486-AML-001) examines CC-486 maintenance therapy (300 mg/day for 14 days of 28-day treatment cycles) for patients aged ≥55 years with AML in first complete remission. The primary end point is overall survival. Secondary end points include relapse-free survival, safety, health-related quality of life and healthcare resource utilization. This trial will investigate whether CC-486 maintenance can prolong remission and improve survival for older patients with AML.

Phase multistability in a dynamical small world network

Energy Technology Data Exchange (ETDEWEB)

Shabunin, A. V., E-mail: shabuninav@info.sgu.ru [Radiophysics and Nonlinear Dynamics Department, Saratov State University, Saratov (Russian Federation)

2015-01-15

The effect of phase multistability is explored in a small world network of periodic oscillators with diffusive couplings. The structure of the network represents a ring with additional non-local links, which spontaneously arise and vanish between arbitrary nodes. The dynamics of random couplings is modeled by “birth” and “death” stochastic processes by means of the cellular automate approach. The evolution of the network under gradual increasing of the number of random couplings goes through stages of phases fluctuations and spatial cluster formation. Finally, in the presence of non-local couplings the phase multistability “dies” and only the in-phase regime survives.

A 0.18-μm 3.3 V 16 k Bits 1R1T Phase Change Random Access Memory (PCRAM) Chip

International Nuclear Information System (INIS)

Sheng, Ding; Zhi-Tang, Song; Bo, Liu; Min, Zhu; Xiao-Gang, Chen; Yi-Feng, Chen; Ju, Shen; Cong, Fu; Song-Lin, Feng

2008-01-01

Using standard 0.18-μm CMOS process and the special platform for 8-inch phase change random access memory (PCRAM), the first Chinese 16k bits PCRAM chip has been successfully achieved. A 1R1T structure has been designed for low voltage drop and low cost compared to the 1R1D structure and the BJT-switch structure. Full integration of the 16k bits PCRAM chip, including memory cell, array structure, critical circuit module, and physical layout, has been designed and verified. The critical integration technology of the phase change material (PCM) fabrication and the standard CMOS process has been solved. Test results about PCM in a large-scale array have been generated for the next research of PCRAM chip

Phase statistics in non-Gaussian scattering

International Nuclear Information System (INIS)

Watson, Stephen M; Jakeman, Eric; Ridley, Kevin D

2006-01-01

Amplitude weighting can improve the accuracy of frequency measurements in signals corrupted by multiplicative speckle noise. When the speckle field constitutes a circular complex Gaussian process, the optimal function of amplitude weighting is provided by the field intensity, corresponding to the intensity-weighted phase derivative statistic. In this paper, we investigate the phase derivative and intensity-weighted phase derivative returned from a two-dimensional random walk, which constitutes a generic scattering model capable of producing both Gaussian and non-Gaussian fluctuations. Analytical results are developed for the correlation properties of the intensity-weighted phase derivative, as well as limiting probability densities of the scattered field. Numerical simulation is used to generate further probability densities and determine optimal weighting criteria from non-Gaussian fields. The results are relevant to frequency retrieval in radiation scattered from random media

Dynamic and static correlation functions in the inhomogeneous Hartree-Fock-state approach with random-phase-approximation fluctuations

International Nuclear Information System (INIS)

Lorenzana, J.; Grynberg, M.D.; Yu, L.; Yonemitsu, K.; Bishop, A.R.

1992-11-01

The ground state energy, and static and dynamic correlation functions are investigated in the inhomogeneous Hartree-Fock (HF) plus random phase approximation (RPA) approach applied to a one-dimensional spinless fermion model showing self-trapped doping states at the mean field level. Results are compared with homogeneous HF and exact diagonalization. RPA fluctuations added to the generally inhomogeneous HF ground state allows the computation of dynamical correlation functions that compare well with exact diagonalization results. The RPA correction to the ground state energy agrees well with the exact results at strong and weak coupling limits. We also compare it with a related quasi-boson approach. The instability towards self-trapped behaviour is signaled by a RPA mode with frequency approaching zero. (author). 21 refs, 10 figs

Efficacy, Safety, and Dose of Pafuramidine, a New Oral Drug for Treatment of First Stage Sleeping Sickness, in a Phase 2a Clinical Study and Phase 2b Randomized Clinical Studies.

Directory of Open Access Journals (Sweden)

Christian Burri

2016-02-01

Full Text Available Sleeping sickness (human African trypanosomiasis [HAT] is caused by protozoan parasites and characterized by a chronic progressive course, which may last up to several years before death. We conducted two Phase 2 studies to determine the efficacy and safety of oral pafuramidine in African patients with first stage HAT.The Phase 2a study was an open-label, non-controlled, proof-of-concept study where 32 patients were treated with 100 mg of pafuramidine orally twice a day (BID for 5 days at two trypanosomiasis reference centers (Angola and the Democratic Republic of the Congo [DRC] between August 2001 and November 2004. The Phase 2b study compared pafuramidine in 41 patients versus standard pentamidine therapy in 40 patients. The Phase 2b study was open-label, parallel-group, controlled, randomized, and conducted at two sites in the DRC between April 2003 and February 2007. The Phase 2b study was then amended to add an open-label sequence (Phase 2b-2, where 30 patients received pafuramidine for 10 days. The primary efficacy endpoint was parasitologic cure at 24 hours (Phase 2a or 3 months (Phase 2b after treatment completion. The primary safety outcome was the rate of occurrence of World Health Organization Toxicity Scale Grade 3 or higher adverse events. All subjects provided written informed consent.Pafuramidine for the treatment of first stage HAT was comparable in efficacy to pentamidine after 10 days of dosing. The cure rates 3 months post-treatment were 79% in the 5-day pafuramidine, 100% in the 7-day pentamidine, and 93% in the 10-day pafuramidine groups. In Phase 2b, the percentage of patients with at least 1 treatment-emergent adverse event was notably higher after pentamidine treatment (93% than pafuramidine treatment for 5 days (25% and 10 days (57%. These results support continuation of the development program for pafuramidine into Phase 3.

Efficacy, Safety, and Dose of Pafuramidine, a New Oral Drug for Treatment of First Stage Sleeping Sickness, in a Phase 2a Clinical Study and Phase 2b Randomized Clinical Studies.

Science.gov (United States)

Burri, Christian; Yeramian, Patrick D; Allen, James L; Merolle, Ada; Serge, Kazadi Kyanza; Mpanya, Alain; Lutumba, Pascal; Mesu, Victor Kande Betu Ku; Bilenge, Constantin Miaka Mia; Lubaki, Jean-Pierre Fina; Mpoto, Alfred Mpoo; Thompson, Mark; Munungu, Blaise Fungula; Manuel, Francisco; Josenando, Théophilo; Bernhard, Sonja C; Olson, Carol A; Blum, Johannes; Tidwell, Richard R; Pohlig, Gabriele

2016-02-01

Sleeping sickness (human African trypanosomiasis [HAT]) is caused by protozoan parasites and characterized by a chronic progressive course, which may last up to several years before death. We conducted two Phase 2 studies to determine the efficacy and safety of oral pafuramidine in African patients with first stage HAT. The Phase 2a study was an open-label, non-controlled, proof-of-concept study where 32 patients were treated with 100 mg of pafuramidine orally twice a day (BID) for 5 days at two trypanosomiasis reference centers (Angola and the Democratic Republic of the Congo [DRC]) between August 2001 and November 2004. The Phase 2b study compared pafuramidine in 41 patients versus standard pentamidine therapy in 40 patients. The Phase 2b study was open-label, parallel-group, controlled, randomized, and conducted at two sites in the DRC between April 2003 and February 2007. The Phase 2b study was then amended to add an open-label sequence (Phase 2b-2), where 30 patients received pafuramidine for 10 days. The primary efficacy endpoint was parasitologic cure at 24 hours (Phase 2a) or 3 months (Phase 2b) after treatment completion. The primary safety outcome was the rate of occurrence of World Health Organization Toxicity Scale Grade 3 or higher adverse events. All subjects provided written informed consent. Pafuramidine for the treatment of first stage HAT was comparable in efficacy to pentamidine after 10 days of dosing. The cure rates 3 months post-treatment were 79% in the 5-day pafuramidine, 100% in the 7-day pentamidine, and 93% in the 10-day pafuramidine groups. In Phase 2b, the percentage of patients with at least 1 treatment-emergent adverse event was notably higher after pentamidine treatment (93%) than pafuramidine treatment for 5 days (25%) and 10 days (57%). These results support continuation of the development program for pafuramidine into Phase 3.

Randomized Phase II Trial of High-Dose Melatonin and Radiation Therapy for RPA Class 2 Patients With Brain Metastases (RTOG 0119)

International Nuclear Information System (INIS)

Berk, Lawrence; Berkey, Brian; Rich, Tyvin; Hrushesky, William; Blask, David; Gallagher, Michael; Kudrimoti, Mahesh; McGarry, Ronald C.; Suh, John; Mehta, Minesh

2007-01-01

Purpose: To determine if high-dose melatonin for Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) Class 2 patients with brain metastases improved survival over historical controls, and to determine if the time of day melatonin was given affected its toxicity or efficacy. RTOG 0119 was a phase II randomized trial for this group of patients. Methods and Materials: RTOG RPA Class 2 patients with brain metastases were randomized to 20 mg of melatonin, given either in the morning (8-9 AM) or in the evening (8-9 PM). All patients received radiation therapy (30 Gy in 10 fractions) in the afternoon. Melatonin was continued until neurologic deterioration or death. The primary endpoint was overall survival time. Neurologic deterioration, as reflected by the Mini-Mental Status Examination, was also measured. Results: Neither of the randomized groups had survival distributions that differed significantly from the historic controls of patients treated with whole-brain radiotherapy. The median survivals of the morning and evening melatonin treatments were 3.4 and 2.8 months, while the RTOG historical control survival was 4.1 months. Conclusions: High-dose melatonin did not show any beneficial effect in this group of patients

Critical Behaviour of a Two-Dimensional Random Antiferromagnet

DEFF Research Database (Denmark)

Als-Nielsen, Jens Aage; Birgeneau, R. J.; Guggenheim, H. J.

1976-01-01

A neutron scattering study of the order parameter, correlation length and staggered susceptibility of the two-dimensional random antiferromagnet Rb2Mn0.5Ni0.5F4 is reported. The system is found to exhibit a well-defined phase transition with critical exponents identical to those of the isomorphou...... pure materials K2NiF4 and K2MnF4. Thus, in these systems, which have the asymptotic critical behaviour of the two-dimensional Ising model, randomness has no measurable effect on the phase-transition behaviour....

An Open-Label, Multicenter, Randomized, Phase II Study of Pazopanib in Combination with Pemetrexed in First-Line Treatment of Patients with Advanced-Stage Non-Small-Cell Lung Cancer

DEFF Research Database (Denmark)

Scagliotti, Giorgio V; Felip, Enriqueta; Besse, Benjamin

2013-01-01

This randomized open-label phase II study evaluated the efficacy, safety, and tolerability of pazopanib in combination with pemetrexed compared with the standard cisplatin/pemetrexed doublet in patients with previously untreated, advanced, nonsquamous non-small-cell lung cancer....

Iodixanol in cerebral computed tomography: a randomized, double-blind, phase-III, parallel study with iodixanol and iohexol

International Nuclear Information System (INIS)

Doerfler, A.; Wanke, I.; Forsting, M.; Fiebach, J.; Sartor, K.; Henseke, P.

1999-01-01

Iodixanol is a new nonionic dimer, isotonic with blood at all clinically relevant concentrations. Iodixanol (270 mg I/ml) was compared in a double-blind, randomized, parallel-group, phase-III study to the monomeric nonionic iohexol (300 mg I/ml) for evaluation of safety, tolerability and radiographic efficacy during cerebral CT. One hundred adult patients scheduled to undergo contrast-enhanced cerebral CT were randomly allocated to receive either iodixanol or iohexol. All completed the trial. Safety was evaluated by recording discomfort and other adverse events, tolerance by assessing intensity and incidence of discomfort. Radiographic efficacy was assessed from the diagnostic information and the radiographic density. No serious adverse events occurred. One patient (2 %) in the iodixanol group and one patient (2 %) in the iohexol group experienced a transient reddening at the neck and lower neck-line, respectively. Both contrast agents were well tolerated. One patient (2 %) in the iodixanol group and two patients (4 %) in the iohexol group experienced a sensation of warmth (discomfort) in connection with the injection. No difference between the two contrast media were noted radiographically. This comparison between iodixanol and iohexol showed both contrast media to be safe, well-tolerated and efficacious for use in cerebral CT. (orig.)

Designing the selenium and bladder cancer trial (SELEBLAT, a phase lll randomized chemoprevention study with selenium on recurrence of bladder cancer in Belgium

Directory of Open Access Journals (Sweden)

Goossens Maria E

2012-03-01

Full Text Available Abstract Background In Belgium, bladder cancer is the fifth most common cancer in males (5.2% and the sixth most frequent cause of death from cancer in males (3.8%. Previous epidemiological studies have consistently reported that selenium concentrations were inversely associated with the risk of bladder cancer. This suggests that selenium may also be suitable for chemoprevention of recurrence. Method The SELEBLAT study opened in September 2009 and is still recruiting all patients with non-invasive transitional cell carcinoma of the bladder on TURB operation in 15 Belgian hospitals. Recruitment progress can be monitored live at http://www.seleblat.org. Patients are randomly assigned to selenium yeast (200 μg/day supplementation for 3 years or matching placebo, in addition to standard care. The objective is to determine the effect of selenium on the recurrence of bladder cancer. Randomization is stratified by treatment centre. A computerized algorithm randomly assigns the patients to a treatment arm. All study personnel and participants are blinded to treatment assignment for the duration of the study. Design The SELEnium and BLAdder cancer Trial (SELEBLAT is a phase III randomized, placebo-controlled, academic, double-blind superior trial. Discussion This is the first report on a selenium randomized trial in bladder cancer patients. Trial registration ClinicalTrials.gov identifier: NCT00729287

Vandetanib in patients with locally advanced or metastatic medullary thyroid cancer: a randomized, double-blind phase III trial.

Science.gov (United States)

Wells, Samuel A; Robinson, Bruce G; Gagel, Robert F; Dralle, Henning; Fagin, James A; Santoro, Massimo; Baudin, Eric; Elisei, Rossella; Jarzab, Barbara; Vasselli, James R; Read, Jessica; Langmuir, Peter; Ryan, Anderson J; Schlumberger, Martin J

2012-01-10

There is no effective therapy for patients with advanced medullary thyroid carcinoma (MTC). Vandetanib, a once-daily oral inhibitor of RET kinase, vascular endothelial growth factor receptor, and epidermal growth factor receptor signaling, has previously shown antitumor activity in a phase II study of patients with advanced hereditary MTC. Patients with advanced MTC were randomly assigned in a 2:1 ratio to receive vandetanib 300 mg/d or placebo. On objective disease progression, patients could elect to receive open-label vandetanib. The primary end point was progression-free survival (PFS), determined by independent central Response Evaluation Criteria in Solid Tumors (RECIST) assessments. Between December 2006 and November 2007, 331 patients (mean age, 52 years; 90% sporadic; 95% metastatic) were randomly assigned to receive vandetanib (231) or placebo (100). At data cutoff (July 2009; median follow-up, 24 months), 37% of patients had progressed and 15% had died. The study met its primary objective of PFS prolongation with vandetanib versus placebo (hazard ratio [HR], 0.46; 95% CI, 0.31 to 0.69; P < .001). Statistically significant advantages for vandetanib were also seen for objective response rate (P < .001), disease control rate (P = .001), and biochemical response (P < .001). Overall survival data were immature at data cutoff (HR, 0.89; 95% CI, 0.48 to 1.65). A final survival analysis will take place when 50% of the patients have died. Common adverse events (any grade) occurred more frequently with vandetanib compared with placebo, including diarrhea (56% v 26%), rash (45% v 11%), nausea (33% v 16%), hypertension (32% v 5%), and headache (26% v 9%). Vandetanib demonstrated therapeutic efficacy in a phase III trial of patients with advanced MTC (ClinicalTrials.gov NCT00410761).

Lectures on random interfaces

CERN Document Server

Funaki, Tadahisa

2016-01-01

Interfaces are created to separate two distinct phases in a situation in which phase coexistence occurs. This book discusses randomly fluctuating interfaces in several different settings and from several points of view: discrete/continuum, microscopic/macroscopic, and static/dynamic theories. The following four topics in particular are dealt with in the book. Assuming that the interface is represented as a height function measured from a fixed-reference discretized hyperplane, the system is governed by the Hamiltonian of gradient of the height functions. This is a kind of effective interface model called ∇φ-interface model. The scaling limits are studied for Gaussian (or non-Gaussian) random fields with a pinning effect under a situation in which the rate functional of the corresponding large deviation principle has non-unique minimizers. Young diagrams determine decreasing interfaces, and their dynamics are introduced. The large-scale behavior of such dynamics is studied from the points of view of the hyd...

On a numereeical method for solving the Faddv integral equation without deformation of contour

International Nuclear Information System (INIS)

Belyaev, V.O.; Moller, K.

1976-01-01

A numerical method is proposed for solving the Faddeev equation for separable potentials at positive total energy. The method is based on the fact that after applying a simple interpolation procedure the logarithmic singularities in the kernel of the integral equation can be extracted in the same way as usually the pole singularity is extracted. The method has been applied to calculate the eigenvalues of the Faddeev kernel

Phase Error Modeling and Its Impact on Precise Orbit Determination of GRACE Satellites

Directory of Open Access Journals (Sweden)

Jia Tu

2012-01-01

Full Text Available Limiting factors for the precise orbit determination (POD of low-earth orbit (LEO satellite using dual-frequency GPS are nowadays mainly encountered with the in-flight phase error modeling. The phase error is modeled as a systematic and a random component each depending on the direction of GPS signal reception. The systematic part and standard deviation of random part in phase error model are, respectively, estimated by bin-wise mean and standard deviation values of phase postfit residuals computed by orbit determination. By removing the systematic component and adjusting the weight of phase observation data according to standard deviation of random component, the orbit can be further improved by POD approach. The GRACE data of 1–31 January 2006 are processed, and three types of orbit solutions, POD without phase error model correction, POD with mean value correction of phase error model, and POD with phase error model correction, are obtained. The three-dimensional (3D orbit improvements derived from phase error model correction are 0.0153 m for GRACE A and 0.0131 m for GRACE B, and the 3D influences arisen from random part of phase error model are 0.0068 m and 0.0075 m for GRACE A and GRACE B, respectively. Thus the random part of phase error model cannot be neglected for POD. It is also demonstrated by phase postfit residual analysis, orbit comparison with JPL precise science orbit, and orbit validation with KBR data that the results derived from POD with phase error model correction are better than another two types of orbit solutions generated in this paper.

The time-dependent relativistic mean-field theory and the random phase approximation

International Nuclear Information System (INIS)

Ring, P.; Ma, Zhong-yu; Van Giai, Nguyen; Vretenar, D.; Wandelt, A.; Cao, Li-gang

2001-01-01

The Relativistic Random Phase Approximation (RRPA) is derived from the Time-Dependent Relativistic Mean-Field (TD RMF) theory in the limit of small amplitude oscillations. In the no-sea approximation of the RMF theory, the RRPA configuration space includes not only the usual particle-hole ph-states, but also αh-configurations, i.e. pairs formed from occupied states in the Fermi sea and empty negative-energy states in the Dirac sea. The contribution of the negative-energy states to the RRPA matrices is examined in a schematic model, and the large effect of Dirac-sea states on isoscalar strength distributions is illustrated for the giant monopole resonance in 116 Sn. It is shown that, because the matrix elements of the time-like component of the vector-meson fields which couple the αh-configurations with the ph-configurations are strongly reduced with respect to the corresponding matrix elements of the isoscalar scalar meson field, the inclusion of states with unperturbed energies more than 1.2 GeV below the Fermi energy has a pronounced effect on giant resonances with excitation energies in the MeV region. The influence of nuclear magnetism, i.e. the effect of the spatial components of the vector fields is examined, and the difference between the nonrelativistic and relativistic RPA predictions for the nuclear matter compression modulus is explained

Magnetically induced crystal structure and phase stability in Fe1-cCoc

DEFF Research Database (Denmark)

Abrikosov, I.A.; James, P.; Eriksson, O.

1996-01-01

We present an ab initio determination of the crystallographic phase stability of Fe-Co alloys as a function of concentration, using the coherent potential approximation. A bcc --> hcp phase transition is found at a concentration of 85 at.% of Co, in good agreement with the experimental phase...... diagram. We demonstrate that for the Pe-rich random alloys magnetism-stabilizes the bce phase relative to the close-packed fee and hcp phases. Magnetism also favors the partially ordered alpha' phase relative to the random bce alloy. This unique relation between magnetism and phase stability for the Fe...

Sunitinib versus sorafenib in advanced hepatocellular cancer: results of a randomized phase III trial.

Science.gov (United States)

Cheng, Ann-Lii; Kang, Yoon-Koo; Lin, Deng-Yn; Park, Joong-Won; Kudo, Masatoshi; Qin, Shukui; Chung, Hyun-Cheol; Song, Xiangqun; Xu, Jianming; Poggi, Guido; Omata, Masao; Pitman Lowenthal, Susan; Lanzalone, Silvana; Yang, Liqiang; Lechuga, Maria Jose; Raymond, Eric

2013-11-10

Open-label, phase III trial evaluating whether sunitinib was superior or equivalent to sorafenib in hepatocellular cancer. Patients were stratified and randomly assigned to receive sunitinib 37.5 mg once per day or sorafenib 400 mg twice per day. Primary end point was overall survival (OS). Early trial termination occurred for futility and safety reasons. A total of 1,074 patients were randomly assigned to the study (sunitinib arm, n = 530; sorafenib arm, n = 544). For sunitinib and sorafenib, respectively, median OS was 7.9 versus 10.2 months (hazard ratio [HR], 1.30; one-sided P = .9990; two-sided P = .0014); median progression-free survival (PFS; 3.6 v 3.0 months; HR, 1.13; one-sided P = .8785; two-sided P = .2286) and time to progression (TTP; 4.1 v 3.8 months; HR, 1.13; one-sided P = .8312; two-sided P = .3082) were comparable. Median OS was similar among Asian (7.7 v 8.8 months; HR, 1.21; one-sided P = .9829) and hepatitis B-infected patients (7.6 v 8.0 months; HR, 1.10; one-sided P = .8286), but was shorter with sunitinib in hepatitis C-infected patients (9.2 v 17.6 months; HR, 1.52; one-sided P = .9835). Sunitinib was associated with more frequent and severe adverse events (AEs) than sorafenib. Common grade 3/4 AEs were thrombocytopenia (29.7%) and neutropenia (25.7%) for sunitinib; hand-foot syndrome (21.2%) for sorafenib. Discontinuations owing to AEs were similar (sunitinib, 13.3%; sorafenib, 12.7%). OS with sunitinib was not superior or equivalent but was significantly inferior to sorafenib. OS was comparable in Asian and hepatitis B-infected patients. OS was superior in hepatitis C-infected patients who received sorafenib. Sunitinib-treated patients reported more frequent and severe toxicity.

Optimal scheme of postoperative chemoradiotherapy in rectal cancer: phase III prospective randomized trial

International Nuclear Information System (INIS)

Kim, Young Seok; Kim, Jong Hoon; Choi, Eun Kyung

2002-01-01

To determine the optimal scheme of postoperative chemoradiotherapy in rectal cancer by comparing survival, patterns of failure, toxicities in early and late radiotherapy groups using a phase III randomized prospective clinical trial. From January 1996 to March 1999, 307 patients with curatively resected AJCC stage II and III rectal cancer were assigned randomly to an 'early (151 patients, arm I)' or a 'late (156 patients, arm II)' and were administered combined chemotherapy (5-FU 375 mg/m 2 /day, leucovorin 20 mg/m 2 , IV bolus daily, for 3 days with RT, 5 days without RT, 8 cycles with 4 weeks interval) and radiation therapy (whole pelvis with 45 Gy/25 fractions/5 weeks). Patients of arm I received radiation therapy from day 1 of the first cycle of chemotherapy and those of arm II from day 57 with a third cycle of chemotherapy. The median follow-up period of living patients was 40 months. Of the 307 patients enrolled, fifty patients did not receive scheduled radiation therapy or chemotherapy. The overall survival rate and disease free survival rate at 5 years were 78.3% and 68.7% in arm I, and 78.4% and 67.5% in arm II. The local recurrence rate was 6.6% and 6.4% (ρ = 0.46) in arms I and II, respectively, no significant difference was observed between the distant metastasis rates of the two arms (23.8% and 29.5%, ρ = 0.16). During radiation therapy, grade 3 diarrhea or more, by the NCI common toxicity criteria, was observed in 63.0% and 58.2% of the respective arms (ρ = N.S.), but most were controlled with supportive care. Hematologic toxicity (leukopenia) greater than RTOG grade 2 was found in only 1.3% and 2.6% of patients in each respective arm. There was no significant difference in survival, patterns of failure or toxicities between the early and late radiation therapy arms. Postoperative adjuvant chemoradiation was found to be a relatively safe treatment but higher compliance is needed

Once daily controlled-release pregabalin in the treatment of patients with fibromyalgia: a phase III, double-blind, randomized withdrawal, placebo-controlled study.

Science.gov (United States)

Arnold, Lesley M; Arsenault, Pierre; Huffman, Cynthia; Patrick, Jeffrey L; Messig, Michael; Chew, Marci L; Sanin, Luis; Scavone, Joseph M; Pauer, Lynne; Clair, Andrew G

2014-10-01

Safety and efficacy of a once daily controlled-released (CR) formulation of pregabalin was evaluated in patients with fibromyalgia using a placebo-controlled, randomized withdrawal design. This multicenter study included 6 week single-blind pregabalin CR treatment followed by 13 week double-blind treatment with placebo or pregabalin CR. The starting dose of 165 mg/day was escalated during the first 3 weeks, up to 495 mg/day based on efficacy and tolerability. Patients with ≥50% reduction in average daily pain score at the end of the single-blind phase were randomized to continue pregabalin CR at the optimized dose (330-495 mg/day) or to placebo. The primary endpoint was time to loss of therapeutic response (LTR), defined as treatment' (Benefit, Satisfaction, and Willingness to Continue Scale) in the pregabalin CR group; no other secondary endpoints were statistically significant. Most AEs were mild to moderate in severity (most frequent: dizziness, somnolence). The percentage of pregabalin CR patients discontinuing because of AEs was 12.2% and 4.8% in the single-blind and double-blind phases, respectively (placebo, 0%). Time to LTR was significantly longer with pregabalin CR versus placebo in fibromyalgia patients who initially showed improvement with pregabalin CR, indicating maintenance of response. Pregabalin CR was well tolerated in most patients. Generalizability may be limited by study duration and selective population.

Configuration space Faddeev calculations

International Nuclear Information System (INIS)

Payne, G.L.; Klink, W.H.; Polyzou, W.N.

1992-12-01

The detailed study of few-body systems provides one of the most precise tools for studying the dynamics of nuclei and nucleons. This research program consists of a careful theoretical study of few-body systems and methods for modeling these systems. During the past year several aspects of this program were completed. Brief summaries are given of work on the following topics: The relativistic three quark problem; the relativistic Balian-Brezin method; spin in light front quantum mechanical models; proton-deutron scattering and reactions; point form relativistic quantum mechanics of constituents; solutions of quantum mechanical anharmonic oscillators; shift operators and the U(N) multiplicity problem

Continuum random-phase approximation study of the incoherent μ--e- conversion rate and its spurious 1- admixture

International Nuclear Information System (INIS)

Papakonstantinou, P.; Wambach, J.; Kosmas, T.S.; Faessler, A.

2006-01-01

The incoherent transition strength of the exotic μ - -e - conversion in the 208 Pb nucleus is investigated by utilizing the continuum random-phase-approximation method, appropriate for the evaluation of the rate that goes to the continuum of the nuclear spectrum. We find that the contribution of resonances lying high in the continuum is not negligible. Special attention is paid to the detailed study of the pronounced 1 - contribution that according to previous calculations, dominates the overall incoherent rate in about all the nuclear targets. The spurious center-of-mass admixture to the partial rate originating from the 1 - excitations is explored, and its elimination is performed by correcting properly the dipole operators. The results found this way show that the greatest portion of the total 1 - contribution to the incoherent rate is spurious

Quantum-mechanical few-body scattering equations with half-on-shell energy-independent subsystem input

International Nuclear Information System (INIS)

Zeiger, E.M.

1978-01-01

New equations are presented for three- and four-body scattering, within the context of nonrelativistic quantum mechanics and a Hamiltonian scattering theory. For the three-body case Faddeev-type equations are presented which, although obtained from the rigorous Faddeev theory, only require two-body bound state wave functions and half-off-shell transition amplitudes as input. In addition, their effective potentials are independent of the three-body energy, and can easily be made real after an angular momentum decomposition. The equations are formulated in terms of physical transition amplitudes for three-body processes, except that in the breakup case the partial-wave amplitudes differ from the corresponding full amplitudes by a Watson final-state-interaction factor. Also presented are new equations for four-body scattering, obtained by generalizing our three-body formalism to the four-body case. These equations, although equivalent to those of Faddeev--Yakubovskii, are expressed in terms of singularity-free transition amplitudes, and their energy-independent effective potentials require only half-on-shell subsystem transition amplitudes (and bound state wave functions) as input. However, due to the detailed index structure of the Faddeev--Yakubovskii formalsim, the result of the generalization is considerably more complicated than in the three-body case

A phase 2 randomized trial of ELND005, scyllo-inositol, in mild to moderate Alzheimer disease

Science.gov (United States)

Sperling, R.; Keren, R.; Porsteinsson, A.P.; van Dyck, C.H.; Tariot, P.N.; Gilman, S.; Arnold, D.; Abushakra, S.; Hernandez, C.; Crans, G.; Liang, E.; Quinn, G.; Bairu, M.; Pastrak, A.; Cedarbaum, J.M.

2011-01-01

Objective: This randomized, double-blind, placebo-controlled, dose-ranging phase 2 study explored safety, efficacy, and biomarker effects of ELND005 (an oral amyloid anti-aggregation agent) in mild to moderate Alzheimer disease (AD). Methods: A total of 353 patients were randomized to ELND005 (250, 1,000, or 2,000 mg) or placebo twice daily for 78 weeks. Coprimary endpoints were the Neuropsychological Test Battery (NTB) and Alzheimer's Disease Cooperative Study–Activities of Daily Living (ADCS-ADL) scale. The primary analysis compared 250 mg (n =84) to placebo (n =82) after an imbalance of infections and deaths led to early discontinuation of the 2 higher dose groups. Results: The 250 mg dose demonstrated acceptable safety. The primary efficacy analysis at 78 weeks revealed no significant differences between the treatment groups on the NTB or ADCS-ADL. Brain ventricular volume showed a small but significant increase in the overall 250 mg group (p =0.049). At the 250 mg dose, scyllo-inositol concentrations increased in CSF and brain and CSF Aβx-42 was decreased significantly compared to placebo (p =0.009). Conclusions: Primary clinical efficacy outcomes were not significant. The safety and CSF biomarker results will guide selection of the optimal dose for future studies, which will target earlier stages of AD. Classification of evidence: Due to the small sample sizes, this Class II trial provides insufficient evidence to support or refute a benefit of ELND005. PMID:21917766

Using a short-pulse diffraction-limited laser beam to probe filamentation of a random phase plate smoothed beam

International Nuclear Information System (INIS)

Kline, J. L.; Montgomery, D. S.; Flippo, K. A.; Johnson, R. P.; Rose, H. A.; Shimada, T.; Williams, E. A.

2008-01-01

A short pulse (few picoseconds) laser probe provides high temporal resolution measurements to elucidate details of fast dynamic phenomena not observable with typical longer laser pulse probes and gated diagnostics. Such a short pulse laser probe (SPLP) has been used to measure filamentation of a random phase plate (RPP) smoothed laser beam in a gas-jet plasma. The plasma index of refraction due to driven density and temperature fluctuations by the RPP beam perturbs the phase front of a SPLP propagating at a 90 deg. angle with respect to the RPP interaction beam. The density and temperature fluctuations are quasistatic on the time scale of the SPLP (∼2 ps). The transmitted near-field intensity distribution from the SPLP provides a measure of the phase front perturbation. At low plasma densities, the transmitted intensity pattern is asymmetric with striations across the entire probe beam in the direction of the RPP smoothed beam. As the plasma density increases, the striations break up into smaller sizes along the direction of the RPP beam propagation. The breakup of the intensity pattern is consistent with self-focusing of the RPP smoothed interaction beam. Simulations of the experiment using the wave propagation code, PF3D, are in qualitative agreement demonstrating that the asymmetric striations can be attributed to the RPP driven density fluctuations. Quantification of the beam breakup measured by the transmitted SPLP could lead to a new method for measuring self-focusing of lasers in underdense plasmas.

Using a short-pulse diffraction-limited laser beam to probe filamentation of a random phase plate smoothed beam.

Science.gov (United States)

Kline, J L; Montgomery, D S; Flippo, K A; Johnson, R P; Rose, H A; Shimada, T; Williams, E A

2008-10-01

A short pulse (few picoseconds) laser probe provides high temporal resolution measurements to elucidate details of fast dynamic phenomena not observable with typical longer laser pulse probes and gated diagnostics. Such a short pulse laser probe (SPLP) has been used to measure filamentation of a random phase plate (RPP) smoothed laser beam in a gas-jet plasma. The plasma index of refraction due to driven density and temperature fluctuations by the RPP beam perturbs the phase front of a SPLP propagating at a 90 degree angle with respect to the RPP interaction beam. The density and temperature fluctuations are quasistatic on the time scale of the SPLP (approximately 2 ps). The transmitted near-field intensity distribution from the SPLP provides a measure of the phase front perturbation. At low plasma densities, the transmitted intensity pattern is asymmetric with striations across the entire probe beam in the direction of the RPP smoothed beam. As the plasma density increases, the striations break up into smaller sizes along the direction of the RPP beam propagation. The breakup of the intensity pattern is consistent with self-focusing of the RPP smoothed interaction beam. Simulations of the experiment using the wave propagation code, PF3D, are in qualitative agreement demonstrating that the asymmetric striations can be attributed to the RPP driven density fluctuations. Quantification of the beam breakup measured by the transmitted SPLP could lead to a new method for measuring self-focusing of lasers in underdense plasmas.

An introduction to random interlacements

CERN Document Server

Drewitz, Alexander; Sapozhnikov, Artëm

2014-01-01

This book gives a self-contained introduction to the theory of random interlacements. The intended reader of the book is a graduate student with a background in probability theory who wants to learn about the fundamental results and methods of this rapidly emerging field of research. The model was introduced by Sznitman in 2007 in order to describe the local picture left by the trace of a random walk on a large discrete torus when it runs up to times proportional to the volume of the torus. Random interlacements is a new percolation model on the d-dimensional lattice. The main results covered by the book include the full proof of the local convergence of random walk trace on the torus to random interlacements and the full proof of the percolation phase transition of the vacant set of random interlacements in all dimensions. The reader will become familiar with the techniques relevant to working with the underlying Poisson Process and the method of multi-scale renormalization, which helps in overcoming the ch...

Application of the resonating Hartree-Fock random phase approximation to the Lipkin model

International Nuclear Information System (INIS)

Nishiyama, S.; Ishida, K.; Ido, M.

1996-01-01

We have applied the resonating Hartree-Fock (Res-HF) approximation to the exactly solvable Lipkin model by utilizing a newly developed orbital-optimization algorithm. The Res-HF wave function was superposed by two Slater determinants (S-dets) which give two corresponding local energy minima of monopole ''deformations''. The self-consistent Res-HF calculation gives an excellent ground-state correlation energy. There exist excitations due to small vibrational fluctuations of the orbitals and mixing coefficients around their stationary values. They are described by a new approximation called the resonating Hartree-Fock random phase approximation (Res-HF RPA). Matrices of the second-order variation of the Res-HF energy have the same structures as those of the Res-HF RPA's matrices. The quadratic steepest descent of the Res-HF energy in the orbital optimization is considered to include certainly both effects of RPA-type fluctuations up to higher orders and their mode-mode couplings. It is a very important and interesting task to apply the Res-HF RPA to the Lipkin model with the use of the stationary values and to prove the above argument. It turns out that the Res-HF RPA works far better than the usual HF RPA and the renormalized one. We also show some important features of the Res-HF RPA. (orig.)

Hepatic and vascular enhancement at dual-phase helical CT: comparison of Iobitridol 300 and Iohexol 300 in a prospective randomized study

International Nuclear Information System (INIS)

Legmann, P.; Vignaux, O.; Bahurel, H.; Oudjit, A.; Coste, J.

2001-01-01

The purpose of this study was to determine hepatic and vascular enhancement, clinical tolerance, and iconographic quality of Iobitridol (300 mg/ml) at dual-phase helical CT and to compare it with Iohexol (300 mg/ml). One hundred forty-six patients were randomly divided into two groups. Each group received 120 ml of Iohexol (group A) or Iobitridol (group B). Mean enhancement of liver, aorta and portal vein was obtained at the arterial phase and at the portal-venous phase. Overall image quality was assessed by two independent blinded investigators. Adverse reactions were recorded. There were no significant differences in demographic characteristics and distribution of patient intrinsic parameters between the two groups, except for blood pressure but without statistical correlation between the difference in blood pressure and the impact on enhancement measurements. There was no significant difference in clinical tolerance and image quality. Mean liver as well as aortic and portal vein enhancement measurements did not show any significant difference. Iobitridol compares favorably with Iohexol. Both products have similar safety, tolerance, and efficacy. Both contrast media have equivalent blood pool concentration and interstitial compartment diffusion. (orig.)

Hepatic and vascular enhancement at dual-phase helical CT: comparison of Iobitridol 300 and Iohexol 300 in a prospective randomized study

Energy Technology Data Exchange (ETDEWEB)

Legmann, P.; Vignaux, O.; Bahurel, H.; Oudjit, A. [Dept. of Radiology, Universite Rene Descartes, Paris (France); Coste, J. [Dept. of Biostatistics and Epidemiology, Universite Rene Descartes, Paris (France)

2001-11-01

The purpose of this study was to determine hepatic and vascular enhancement, clinical tolerance, and iconographic quality of Iobitridol (300 mg/ml) at dual-phase helical CT and to compare it with Iohexol (300 mg/ml). One hundred forty-six patients were randomly divided into two groups. Each group received 120 ml of Iohexol (group A) or Iobitridol (group B). Mean enhancement of liver, aorta and portal vein was obtained at the arterial phase and at the portal-venous phase. Overall image quality was assessed by two independent blinded investigators. Adverse reactions were recorded. There were no significant differences in demographic characteristics and distribution of patient intrinsic parameters between the two groups, except for blood pressure but without statistical correlation between the difference in blood pressure and the impact on enhancement measurements. There was no significant difference in clinical tolerance and image quality. Mean liver as well as aortic and portal vein enhancement measurements did not show any significant difference. Iobitridol compares favorably with Iohexol. Both products have similar safety, tolerance, and efficacy. Both contrast media have equivalent blood pool concentration and interstitial compartment diffusion. (orig.)

Antitumor activity and safety of tivozanib (AV-951) in a phase II randomized discontinuation trial in patients with renal cell carcinoma.

Science.gov (United States)

Nosov, Dmitry A; Esteves, Brooke; Lipatov, Oleg N; Lyulko, Alexei A; Anischenko, A A; Chacko, Raju T; Doval, Dinesh C; Strahs, Andrew; Slichenmyer, William J; Bhargava, Pankaj

2012-05-10

The antitumor activity and safety of tivozanib, which is a potent and selective vascular endothelial growth factor receptor-1, -2, and -3 inhibitor, was assessed in patients with advanced/metastatic renal cell carcinoma (RCC). In this phase II, randomized discontinuation trial, 272 patients received open-label tivozanib 1.5 mg/d (one cycle equaled three treatment weeks followed by a 1-week break) orally for 16 weeks. Thereafter, 78 patients who demonstrated ≥ 25% tumor shrinkage continued to take tivozanib, and 118 patients with less than 25% tumor change were randomly assigned to receive tivozanib or a placebo in a double-blind manner; patients with ≥ 25% tumor growth were discontinued. Primary end points included safety, the objective response rate (ORR) at 16 weeks, and the percentage of randomly assigned patients who remained progression free after 12 weeks of double-blind treatment; secondary end points included progression-free survival (PFS). Of 272 patients enrolled onto the study, 83% of patients had clear-cell histology, 73% of patients had undergone nephrectomy, and 54% of patients were treatment naive. The ORR after 16 weeks of tivozanib treatment was 18% (95% CI, 14% to 23%). Of the 118 randomized patients, significantly more patients who were randomly assigned to receive double-blind tivozanib remained progression free after 12 weeks versus patients who received the placebo (49% v 21%; P = .001). Throughout the study, the ORR was 24% (95% CI, 19% to 30%), and the median PFS was 11.7 months (95% CI, 8.3 to 14.3 months) in the overall study population. The most common grade 3 and 4 treatment-related adverse event was hypertension (12%). Tivozanib was active and well tolerated in patients with advanced RCC. These data support additional development of tivozanib in advanced RCC.

Biometrics based key management of double random phase encoding scheme using error control codes

Science.gov (United States)

Saini, Nirmala; Sinha, Aloka

2013-08-01

In this paper, an optical security system has been proposed in which key of the double random phase encoding technique is linked to the biometrics of the user to make it user specific. The error in recognition due to the biometric variation is corrected by encoding the key using the BCH code. A user specific shuffling key is used to increase the separation between genuine and impostor Hamming distance distribution. This shuffling key is then further secured using the RSA public key encryption to enhance the security of the system. XOR operation is performed between the encoded key and the feature vector obtained from the biometrics. The RSA encoded shuffling key and the data obtained from the XOR operation are stored into a token. The main advantage of the present technique is that the key retrieval is possible only in the simultaneous presence of the token and the biometrics of the user which not only authenticates the presence of the original input but also secures the key of the system. Computational experiments showed the effectiveness of the proposed technique for key retrieval in the decryption process by using the live biometrics of the user.

Chiral NNLOsat descriptions of nuclear multipole resonances within the random-phase approximation

Science.gov (United States)

Wu, Q.; Hu, B. S.; Xu, F. R.; Ma, Y. Z.; Dai, S. J.; Sun, Z. H.; Jansen, G. R.

2018-05-01

We study nuclear multipole resonances in the framework of the random-phase approximation by using the chiral potential NNLOsat. This potential includes two- and three-body terms that have been simultaneously optimized to low-energy nucleon-nucleon scattering data and selected nuclear structure data. Our main focuses have been the isoscalar monopole, isovector dipole, and isoscalar quadrupole resonances of the closed-shell nuclei, 4He, O 16 ,22 ,24 , and Ca,4840. These resonance modes have been widely observed in experiment. In addition, we use a renormalized chiral potential Vlow-k, based on the N3LO two-body potential by Entem and Machleidt [Phys. Rev. C 68, 041001 (2011), 10.1103/PhysRevC.68.041001]. This introduces a dependency on the cutoff parameter used in the normalization procedure as reported in previous works by other groups. While NNLOsat can reasonably reproduce observed multipole resonances, it is not possible to find a single cutoff parameter for the Vlow-k potential that simultaneously describes the different types of resonance modes. The sensitivity to the cutoff parameter can be explained by missing induced three-body forces in the calculations. Our results for neutron-rich O,2422 show a mixing nature of isoscalar and isovector resonances in the dipole channel at low energies. We predict that 22O and 24O have low-energy isoscalar quadrupole resonances at energies lower than 5 MeV.

Information verification cryptosystem using one-time keys based on double random phase encoding and public-key cryptography

Science.gov (United States)

Zhao, Tieyu; Ran, Qiwen; Yuan, Lin; Chi, Yingying; Ma, Jing

2016-08-01

A novel image encryption system based on double random phase encoding (DRPE) and RSA public-key algorithm is proposed. The main characteristic of the system is that each encryption process produces a new decryption key (even for the same plaintext), thus the encryption system conforms to the feature of the one-time pad (OTP) cryptography. The other characteristic of the system is the use of fingerprint key. Only with the rightful authorization will the true decryption be obtained, otherwise the decryption will result in noisy images. So the proposed system can be used to determine whether the ciphertext is falsified by attackers. In addition, the system conforms to the basic agreement of asymmetric cryptosystem (ACS) due to the combination with the RSA public-key algorithm. The simulation results show that the encryption scheme has high robustness against the existing attacks.

Description of excited states in the nucleus using the Quasiparticle Random-Phase Approximation and the Gogny interaction

International Nuclear Information System (INIS)

Lechaftois, Francois

2016-01-01

This thesis presents three aspects centered around the QRPA (Quasiparticle Random Phase Approximation). The first consists in the use of an axial code to confront computed data with experimental results and to feed a microscopic reaction code. This step is a chance to analyse low-energy spectroscopy (few tens of MeV) of some nuclei, and more precisely (but not exclusively) the tin isotopic chain (Z=50). The second one relies on the improvement of the formalism to calculate multipolar electromagnetic transition operators, and a method to consolidate the computation of these operators, allowing to ease the programming by unifying the code for different multipolarities. Finally, in order to overcome the axial symmetry constraint, a new triaxial code has been developed. Its assets and development are presented, followed by the first batch of results. (author) [fr

Creactive protein and interleukin-6 as markers of systemic inflammatory response and as prognostic factors for metastatic colorectal cancer. Data from the randomized phase III NORDIC-VII study

DEFF Research Database (Denmark)

Thomsen, M.; Kersten, C.; Sorbye, H.

2015-01-01

-6 (IL-6). Methods: The study was based on data from the randomized phase III NORDIC-VII study (Nordic FLOX +/cetuximab as first line treatment of mCRC). The effect of different markers of SIR, including modified Glasgow Prognostic Score (mGPS), derived Neutrophil Lymphocyte Ratio (dNLR), levels...

Nonvolatile memory design magnetic, resistive, and phase change

CERN Document Server

Li, Hai

2011-01-01

The manufacture of flash memory, which is the dominant nonvolatile memory technology, is facing severe technical barriers. So much so, that some emerging technologies have been proposed as alternatives to flash memory in the nano-regime. Nonvolatile Memory Design: Magnetic, Resistive, and Phase Changing introduces three promising candidates: phase-change memory, magnetic random access memory, and resistive random access memory. The text illustrates the fundamental storage mechanism of these technologies and examines their differences from flash memory techniques. Based on the latest advances,

Robust random number generation using steady-state emission of gain-switched laser diodes

International Nuclear Information System (INIS)

Yuan, Z. L.; Lucamarini, M.; Dynes, J. F.; Fröhlich, B.; Plews, A.; Shields, A. J.

2014-01-01

We demonstrate robust, high-speed random number generation using interference of the steady-state emission of guaranteed random phases, obtained through gain-switching a semiconductor laser diode. Steady-state emission tolerates large temporal pulse misalignments and therefore significantly improves the interference quality. Using an 8-bit digitizer followed by a finite-impulse-response unbiasing algorithm, we achieve random number generation rates of 8 and 20 Gb/s, for laser repetition rates of 1 and 2.5 GHz, respectively, with a ±20% tolerance in the interferometer differential delay. We also report a generation rate of 80 Gb/s using partially phase-correlated short pulses. In relation to the field of quantum key distribution, our results confirm the gain-switched laser diode as a suitable light source, capable of providing phase-randomized coherent pulses at a clock rate of up to 2.5 GHz.

Time gated phase-correlation distributed Brillouin fibre sensor

Science.gov (United States)

Denisov, Andrey; Soto, Marcelo A.; Thévenaz, Luc

2013-05-01

A random access distributed Brillouin fibre sensor is presented, based on phase modulation using a pseudo-random bit sequence (PRBS) together with time gating. The standard phase-correlation technique is known to show a noise level increasing linearly with the number of measured points due to weak gratings generated randomly along the whole sensing fibre. Here we show how intensity modulated pump and time gated detection significantly improve the signal-tonoise ratio (SNR) of the system with no impact on the spatial resolution. A measurement with 1.1 cm spatial resolution over 3.3 km is demonstrated, representing 300'000 equivalent points. The limitations of the proposed technique are discussed through the paper.

Multicenter prospective randomized phase II study of antimicrobial prophylaxis in low-risk patients undergoing colon surgery.

Science.gov (United States)

Shimizu, Junzo; Ikeda, Kimimasa; Fukunaga, Mutsumi; Murata, Kohei; Miyamoto, Atsushi; Umeshita, Koji; Kobayashi, Tetsuro; Monden, Morito

2010-10-01

Postoperative antimicrobial therapy is generally administered as standard prophylaxis against postoperative infection, despite a lack of sufficient evidence for its usefulness. This study was a phase II study to evaluate the necessity of postoperative antibiotic prophylaxis in patients undergoing a colectomy. Patients received 1 g cefmetazole or flomoxef immediately after anesthetic induction, every 3 h during surgery, and then later once again on the next day. They were randomly assigned to receive either cefmetazole or flomoxef. Ninety-one patients were enrolled in the study. A surgical site infection (SSI) occurred in 7.7% (7/91) of patients. All cases were superficial incisional infections. When comparing the two drugs, SSI occurred in 8.3% (4/48) of patients treated with cefmetazole and in 7.0% (3/43) treated with flomoxef, showing no significant difference (P > 0.99). Antimicrobial prophylaxis was well tolerated when used on the day of a colectomy and once again on the next day.

Route to Photo-Enabled Random Terahertz Metasurfaces

KAUST Repository

Peters, Luke; Gongora, J. S. Totero; Tunesi, Jacob D.; Fratalocchi, Andrea; Pasquazi, Alessia; Peccianti, Marco

2017-01-01

We experimentally investigate the enhancement and phase change of the THz emission from photo-excited randomly structured black silicon substrates mediated by an induced metallic state of the nanostructured surface.

Route to Photo-Enabled Random Terahertz Metasurfaces

KAUST Repository

Peters, Luke

2017-07-17

We experimentally investigate the enhancement and phase change of the THz emission from photo-excited randomly structured black silicon substrates mediated by an induced metallic state of the nanostructured surface.

Random coil chemical shifts in acidic 8 M urea: Implementation of random coil shift data in NMRView

International Nuclear Information System (INIS)

Schwarzinger, Stephan; Kroon, Gerard J.A.; Foss, Ted R.; Wright, Peter E.; Dyson, H. Jane

2000-01-01

Studies of proteins unfolded in acid or chemical denaturant can help in unraveling events during the earliest phases of protein folding. In order for meaningful comparisons to be made of residual structure in unfolded states, it is necessary to use random coil chemical shifts that are valid for the experimental system under study. We present a set of random coil chemical shifts obtained for model peptides under experimental conditions used in studies of denatured proteins. This new set, together with previously published data sets, has been incorporated into a software interface for NMRView, allowing selection of the random coil data set that fits the experimental conditions best

Efficient Raman generation in a waveguide: A route to ultrafast quantum random number generation

Energy Technology Data Exchange (ETDEWEB)

England, D. G.; Bustard, P. J.; Moffatt, D. J.; Nunn, J.; Lausten, R.; Sussman, B. J., E-mail: ben.sussman@nrc.ca [National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6 (Canada)

2014-02-03

The inherent uncertainty in quantum mechanics offers a source of true randomness which can be used to produce unbreakable cryptographic keys. We discuss the development of a high-speed random number generator based on the quantum phase fluctuations in spontaneously initiated stimulated Raman scattering (SISRS). We utilize the tight confinement and long interaction length available in a Potassium Titanyl Phosphate waveguide to generate highly efficient SISRS using nanojoule pulse energies, reducing the high pump power requirements of the previous approaches. We measure the random phase of the Stokes output using a simple interferometric setup to yield quantum random numbers at 145 Mbps.

Analyzing phase diagrams and phase transitions in networked competing populations

Science.gov (United States)

Ni, Y.-C.; Yin, H. P.; Xu, C.; Hui, P. M.

2011-03-01

Phase diagrams exhibiting the extent of cooperation in an evolutionary snowdrift game implemented in different networks are studied in detail. We invoke two independent payoff parameters, unlike a single payoff often used in most previous works that restricts the two payoffs to vary in a correlated way. In addition to the phase transition points when a single payoff parameter is used, phase boundaries separating homogeneous phases consisting of agents using the same strategy and a mixed phase consisting of agents using different strategies are found. Analytic expressions of the phase boundaries are obtained by invoking the ideas of the last surviving patterns and the relative alignments of the spectra of payoff values to agents using different strategies. In a Watts-Strogatz regular network, there exists a re-entrant phenomenon in which the system goes from a homogeneous phase into a mixed phase and re-enters the homogeneous phase as one of the two payoff parameters is varied. The non-trivial phase diagram accompanying this re-entrant phenomenon is quantitatively analyzed. The effects of noise and cooperation in randomly rewired Watts-Strogatz networks are also studied. The transition between a mixed phase and a homogeneous phase is identify to belong to the directed percolation universality class. The methods used in the present work are applicable to a wide range of problems in competing populations of networked agents.

Time-dependent Gross-Pitaevskii equation for composite bosons as the strong-coupling limit of the fermionic broken-symmetry random-phase approximation

International Nuclear Information System (INIS)

Strinati, G.C.; Pieri, P.

2004-01-01

The linear response to a space- and time-dependent external disturbance of a system of dilute condensed composite bosons at zero temperature, as obtained from the linearized version of the time-dependent Gross-Pitaevskii equation, is shown to result also from the strong-coupling limit of the time-dependent BCS (or broken-symmetry random-phase) approximation for the constituent fermions subject to the same external disturbance. In this way, it is possible to connect excited-state properties of the bosonic and fermionic systems by placing the Gross-Pitaevskii equation in perspective with the corresponding fermionic approximations

Randomized Phase II Trial of Gemcitabine Plus TH-302 Versus Gemcitabine in Patients With Advanced Pancreatic Cancer.

Science.gov (United States)

Borad, Mitesh J; Reddy, Shantan G; Bahary, Nathan; Uronis, Hope E; Sigal, Darren; Cohn, Allen L; Schelman, William R; Stephenson, Joe; Chiorean, E Gabriela; Rosen, Peter J; Ulrich, Brian; Dragovich, Tomislav; Del Prete, Salvatore A; Rarick, Mark; Eng, Clarence; Kroll, Stew; Ryan, David P

2015-05-01

TH-302 is an investigational hypoxia-activated prodrug that releases the DNA alkylator bromo-isophosphoramide mustard in hypoxic settings. This phase II study (NCT01144455) evaluated gemcitabine plus TH-302 in patients with previously untreated, locally advanced or metastatic pancreatic cancer. Patients were randomly assigned 1:1:1 to gemcitabine (1,000 mg/m(2)), gemcitabine plus TH-302 240 mg/m(2) (G+T240), or gemcitabine plus TH-302 340 mg/m(2) (G+T340). Randomized crossover after progression on gemcitabine was allowed. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), tumor response, CA 19-9 response, and safety. Two hundred fourteen patients (77% with metastatic disease) were enrolled between June 2010 and July 2011. PFS was significantly longer with gemcitabine plus TH-302 (pooled combination arms) compared with gemcitabine alone (median PFS, 5.6 v 3.6 months, respectively; hazard ratio, 0.61; 95% CI, 0.43 to 0.87; P = .005; median PFS for metastatic disease, 5.1 v 3.4 months, respectively). Median PFS times for G+T240 and G+T340 were 5.6 and 6.0 months, respectively. Tumor response was 12%, 17%, and 26% in the gemcitabine, G+T240, and G+T340 arms, respectively (G+T340 v gemcitabine, P = .04). CA 19-9 decrease was greater with G+T340 versus gemcitabine (-5,398 v -549 U/mL, respectively; P = .008). Median OS times for gemcitabine, G+T240, and G+T340 were 6.9, 8.7, and 9.2 months, respectively (P = not significant). The most common adverse events (AEs) were fatigue, nausea, and peripheral edema (frequencies similar across arms). Skin and mucosal toxicities (2% grade 3) and myelosuppression (55% grade 3 or 4) were the most common TH-302-related AEs but were not associated with treatment discontinuation. PFS, tumor response, and CA 19-9 response were significantly improved with G+TH-302. G+T340 is being investigated further in the phase III MAESTRO study (NCT01746979). © 2014 by American Society of

Simulation study on characteristics of long-range interaction in randomly asymmetric exclusion process

Science.gov (United States)

Zhao, Shi-Bo; Liu, Ming-Zhe; Yang, Lan-Ying

2015-04-01

In this paper we investigate the dynamics of an asymmetric exclusion process on a one-dimensional lattice with long-range hopping and random update via Monte Carlo simulations theoretically. Particles in the model will firstly try to hop over successive unoccupied sites with a probability q, which is different from previous exclusion process models. The probability q may represent the random access of particles. Numerical simulations for stationary particle currents, density profiles, and phase diagrams are obtained. There are three possible stationary phases: the low density (LD) phase, high density (HD) phase, and maximal current (MC) in the system, respectively. Interestingly, bulk density in the LD phase tends to zero, while the MC phase is governed by α, β, and q. The HD phase is nearly the same as the normal TASEP, determined by exit rate β. Theoretical analysis is in good agreement with simulation results. The proposed model may provide a better understanding of random interaction dynamics in complex systems. Project supported by the National Natural Science Foundation of China (Grant Nos. 41274109 and 11104022), the Fund for Sichuan Youth Science and Technology Innovation Research Team (Grant No. 2011JTD0013), and the Creative Team Program of Chengdu University of Technology.

Random walk to a nonergodic equilibrium concept

Science.gov (United States)

Bel, G.; Barkai, E.

2006-01-01

Random walk models, such as the trap model, continuous time random walks, and comb models, exhibit weak ergodicity breaking, when the average waiting time is infinite. The open question is, what statistical mechanical theory replaces the canonical Boltzmann-Gibbs theory for such systems? In this paper a nonergodic equilibrium concept is investigated, for a continuous time random walk model in a potential field. In particular we show that in the nonergodic phase the distribution of the occupation time of the particle in a finite region of space approaches U- or W-shaped distributions related to the arcsine law. We show that when conditions of detailed balance are applied, these distributions depend on the partition function of the problem, thus establishing a relation between the nonergodic dynamics and canonical statistical mechanics. In the ergodic phase the distribution function of the occupation times approaches a δ function centered on the value predicted based on standard Boltzmann-Gibbs statistics. The relation of our work to single-molecule experiments is briefly discussed.

Molecular Excitation Energies from Time-Dependent Density Functional Theory Employing Random-Phase Approximation Hessians with Exact Exchange.

Science.gov (United States)

Heßelmann, Andreas

2015-04-14

Molecular excitation energies have been calculated with time-dependent density-functional theory (TDDFT) using random-phase approximation Hessians augmented with exact exchange contributions in various orders. It has been observed that this approach yields fairly accurate local valence excitations if combined with accurate asymptotically corrected exchange-correlation potentials used in the ground-state Kohn-Sham calculations. The inclusion of long-range particle-particle with hole-hole interactions in the kernel leads to errors of 0.14 eV only for the lowest excitations of a selection of three alkene, three carbonyl, and five azabenzene molecules, thus surpassing the accuracy of a number of common TDDFT and even some wave function correlation methods. In the case of long-range charge-transfer excitations, the method typically underestimates accurate reference excitation energies by 8% on average, which is better than with standard hybrid-GGA functionals but worse compared to range-separated functional approximations.

Proton relativistic model

International Nuclear Information System (INIS)

Araujo, Wilson Roberto Barbosa de

1995-01-01

In this dissertation, we present a model for the nucleon, which is composed by three relativistic quarks interacting through a contract force. The nucleon wave-function was obtained from the Faddeev equation in the null-plane. The covariance of the model under kinematical null-plane boots is discussed. The electric proton form-factor, calculated from the Faddeev wave-function, was in agreement with the data for low-momentum transfers and described qualitatively the asymptotic region for momentum transfers around 2 GeV. (author)

Tofacitinib with conventional synthetic disease‐modifying antirheumatic drugs in Chinese patients with rheumatoid arthritis: Patient‐reported outcomes from a Phase 3 randomized controlled trial

OpenAIRE

Li, Zhanguo; An, Yuan; Su, Houheng; Li, Xiangpei; Xu, Jianhua; Zheng, Yi; Li, Guiye; Kwok, Kenneth; Wang, Lisy; Wu, Qizhe

2018-01-01

Abstract Aim Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). We assess the effect of tofacitinib + conventional synthetic disease‐modifying anti rheumatic drugs (csDMARDs) on patient‐reported outcomes in Chinese patients with RA and inadequate response to DMARDs. Methods This analysis of data from the Phase 3 study ORAL Sync included Chinese patients randomized 4 : 4 : 1 : 1 to receive tofacitinib 5 mg twice daily, tofacitinib 10 mg twice daily, p...

Benchmark tests and spin adaptation for the particle-particle random phase approximation

Energy Technology Data Exchange (ETDEWEB)

Yang, Yang; Steinmann, Stephan N.; Peng, Degao [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Aggelen, Helen van, E-mail: Helen.VanAggelen@UGent.be [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Inorganic and Physical Chemistry, Ghent University, 9000 Ghent (Belgium); Yang, Weitao, E-mail: Weitao.Yang@duke.edu [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

2013-11-07

The particle-particle random phase approximation (pp-RPA) provides an approximation to the correlation energy in density functional theory via the adiabatic connection [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)]. It has virtually no delocalization error nor static correlation error for single-bond systems. However, with its formal O(N{sup 6}) scaling, the pp-RPA is computationally expensive. In this paper, we implement a spin-separated and spin-adapted pp-RPA algorithm, which reduces the computational cost by a substantial factor. We then perform benchmark tests on the G2/97 enthalpies of formation database, DBH24 reaction barrier database, and four test sets for non-bonded interactions (HB6/04, CT7/04, DI6/04, and WI9/04). For the G2/97 database, the pp-RPA gives a significantly smaller mean absolute error (8.3 kcal/mol) than the direct particle-hole RPA (ph-RPA) (22.7 kcal/mol). Furthermore, the error in the pp-RPA is nearly constant with the number of atoms in a molecule, while the error in the ph-RPA increases. For chemical reactions involving typical organic closed-shell molecules, pp- and ph-RPA both give accurate reaction energies. Similarly, both RPAs perform well for reaction barriers and nonbonded interactions. These results suggest that the pp-RPA gives reliable energies in chemical applications. The adiabatic connection formalism based on pairing matrix fluctuation is therefore expected to lead to widely applicable and accurate density functionals.

A Randomized, Double-Blind, Placebo-Controlled, Phase 2b Study to Evaluate the Safety and Efficacy of Recombinant Human Soluble Thrombomodulin, ART-123, in Patients With Sepsis and Suspected Disseminated Intravascular Coagulation

NARCIS (Netherlands)

Vincent, Jean-Louis; Ramesh, Mayakonda K.; Ernest, David; Larosa, Steven P.; Pachl, Jan; Aikawa, Naoki; Hoste, Eric; Levy, Howard; Hirman, Joe; Levi, Marcel; Daga, Mradul; Kutsogiannis, Demetrios J.; Crowther, Mark; Bernard, Gordon R.; Devriendt, Jacques; Puigserver, Joan Vidal; Blanzaco, Daniel U.; Esmon, Charles T.; Parrillo, Joseph E.; Guzzi, Louis; Henderson, Seton J.; Pothirat, Chaicharn; Mehta, Parthiv; Fareed, Jawed; Talwar, Deepak; Tsuruta, Kazuhisa; Gorelick, Kenneth J.; Osawa, Yutaka; Kaul, Inder

2013-01-01

Objectives: To determine the safety and efficacy of recombinant thrombomodulin (ART-123) in patients with suspected sepsis-associated disseminated intravascular coagulation. Design: Phase 2b, international, multicenter, double-blind, randomized, placebo-controlled, parallel group, screening trial.

Geometrical critical phenomena on a random surface of arbitrary genus

International Nuclear Information System (INIS)

Duplantier, B.; Kostov, I.K.

1990-01-01

The statistical mechanics of self-avoiding walks (SAW) or of the O(n)-loop model on a two-dimensional random surface are shown to be exactly solvable. The partition functions of SAW and surface configurations (possibly in the presence of vacuum loops) are calculated by planar diagram enumeration techniques. Two critical regimes are found: a dense phase where the infinite walks and loops fill the infinite surface, the non-filled part staying finite, and a dilute phase where the infinite surface singularity on the one hand, and walk and loop singularities on the other, merge together. The configuration critical exponents of self-avoiding networks of any fixed topology G, on a surface with arbitrary genus H, are calculated as universal functions of G and H. For self-avoiding walks, the exponents are built from an infinite set of basic conformal dimensions associated with central charges c = -2 (dense phase) and c = 0 (dilute phase). The conformal spectrum Δ L , L ≥ 1 associated with L-leg star polymers is calculated exactly, for c = -2 and c = 0. This is generalized to the set of L-line 'watermelon' exponents Δ L of the O(n) model on a random surface. The divergences of the partition functions of self-avoiding networks on the random surface, possibly in the presence of vacuum loops, are shown to satisfy a factorization theorem over the vertices of the network. This provides a proof, in the presence of a fluctuating metric, of a result conjectured earlier in the standard plane. From this, the value of the string susceptibility γ str (H,c) is extracted for a random surface of arbitrary genus H, bearing a field theory of central charge c, or equivalently, embedded in d=c dimensions. Lastly, by enumerating spanning trees on a random lattice, we solve the similar problem of hamiltonian walks on the (fluctuating) Manhattan covering lattice. We also obtain new results for dilute trees on a random surface. (orig./HSI)

[Vitex agnus castus extract in the treatment of luteal phase defects due to latent hyperprolactinemia. Results of a randomized placebo-controlled double-blind study].

Science.gov (United States)

Milewicz, A; Gejdel, E; Sworen, H; Sienkiewicz, K; Jedrzejak, J; Teucher, T; Schmitz, H

1993-07-01

The efficacy of a Vitex agnus castus preparation (Strotan capsules) was investigated in a randomized double blind study vs. placebo. This clinical study involved 52 women with luteal phase defects due to latent hyperprolactinaemia. The daily dose was one capsule (20 mg) Vitex agnus castus preparation and placebo, respectively. Aim of the study was to prove whether the elevated pituitary prolactin reserve can be reduced and deficits in luteal phase length and luteal phase progesterone synthesis be normalized. Blood for hormonal analysis was taken at days 5-8 and day 20 of the menstrual cycle before and after three month of therapy. Latent hyperprolactinaemia was analysed by monitoring the prolactin release 15 and 30 min after i.v. injection of 200 micrograms TRH. 37 complete case reports (placebo: n = 20, verum: n = 17) after 3 month of therapy were statistically evaluated. The prolactin release was reduced after 3 months, shortened luteal phases were normalised and deficits in the luteal progesterone synthesis were eliminated. These changes were significant and occurred only in the verum group. All other hormonal parameters did not change with the exception of 17 beta-estradiol which rouse up in the luteal phase in patients receiving verum. Side effects were not seen, two women treated with the Vitex agnus castus preparation got pregnant. The tested preparation is thought to be an efficient medication in the treatment of luteal phase defects due to latent hyperprolactinaemia.

2D gravity, random surfaces and all that

International Nuclear Information System (INIS)

Ambjoern, J.

1990-11-01

I review the recent progress in 2d gravity and discuss the new numerical simulations for 2d gravity and for random surfaces in d>2. The random surface theories of interest in d>2 have extrinsic curvature terms, and for a finite value of the extrinsic curvature coupling there seems to be a second order phase transition where the string tension scales. (orig.)

Quantum random number generation for loophole-free Bell tests

Science.gov (United States)

Mitchell, Morgan; Abellan, Carlos; Amaya, Waldimar

2015-05-01

We describe the generation of quantum random numbers at multi-Gbps rates, combined with real-time randomness extraction, to give very high purity random numbers based on quantum events at most tens of ns in the past. The system satisfies the stringent requirements of quantum non-locality tests that aim to close the timing loophole. We describe the generation mechanism using spontaneous-emission-driven phase diffusion in a semiconductor laser, digitization, and extraction by parity calculation using multi-GHz logic chips. We pay special attention to experimental proof of the quality of the random numbers and analysis of the randomness extraction. In contrast to widely-used models of randomness generators in the computer science literature, we argue that randomness generation by spontaneous emission can be extracted from a single source.

Self-consistent Random Phase Approximation applied to a schematic model of the field theory

International Nuclear Information System (INIS)

Bertrand, Thierry

1998-01-01

The self-consistent Random Phase Approximation (SCRPA) is a method allowing in the mean-field theory inclusion of the correlations in the ground and excited states. It has the advantage of not violating the Pauli principle in contrast to RPA, that is based on the quasi-bosonic approximation; in addition, numerous applications in different domains of physics, show a possible variational character. However, the latter should be formally demonstrated. The first model studied with SCRPA is the anharmonic oscillator in the region where one of its symmetries is spontaneously broken. The ground state energy is reproduced by SCRPA more accurately than RPA, with no violation of the Ritz variational principle, what is not the case for the latter approximation. The success of SCRPA is the the same in case of ground state energy for a model mixing bosons and fermions. At the transition point the SCRPA is correcting RPA drastically, but far from this region the correction becomes negligible, both methods being of similar precision. In the deformed region in the case of RPA a spurious mode occurred due to the microscopical character of the model.. The SCRPA may also reproduce this mode very accurately and actually it coincides with an excitation in the exact spectrum

Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations

International Nuclear Information System (INIS)

Peng, Degao; Yang, Yang; Zhang, Peng; Yang, Weitao

2014-01-01

In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N 4 ). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as 〈S ^2 〉 are also developed and tested

Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations

Energy Technology Data Exchange (ETDEWEB)

Peng, Degao; Yang, Yang; Zhang, Peng [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Yang, Weitao, E-mail: weitao.yang@duke.edu [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

2014-12-07

In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N{sup 4}). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as 〈S{sup ^2}〉 are also developed and tested.

Lanthanum carbonate versus placebo for management of hyperphosphatemia in patients undergoing peritoneal dialysis: a subgroup analysis of a phase 2 randomized controlled study of dialysis patients

Directory of Open Access Journals (Sweden)

Hutchison Alastair J

2013-02-01

Full Text Available Abstract Background This short-term study assessed the efficacy and safety of lanthanum carbonate in the treatment of hyperphosphatemia in dialysis patients; here, we report a prespecified subgroup analysis of patients undergoing peritoneal dialysis. Methods Men and women (n = 39 who had received continuous ambulatory peritoneal dialysis for chronic kidney disease for 6 months or more were enrolled in eight renal medicine departments in the United Kingdom. A 2-week washout period was followed by a 4-week dose-titration phase during which patients received lanthanum carbonate titrated up to 2250 mg/day. This was followed by a 4-week, randomized, placebo-controlled, parallel-group phase during which patients continued to receive either lanthanum carbonate at the titrated dose, or a matched dose of placebo. The main outcome measure was control of serum phosphate levels (1.3-1.8 mmol/l at the end of the parallel-group phase. Results Serum phosphate was controlled in 3/39 (8% patients at the beginning of the dose-titration phase (after washout and in 18/31 (58% patients treated with lanthanum carbonate at its end. After the parallel-group phase, 60% of lanthanum carbonate-treated patients and 10% of those receiving placebo had controlled serum phosphate. There was no difference in mean (95% confidence interval serum phosphate levels between groups at randomization: lanthanum carbonate, 1.57 (1.34-1.81 mmol/l; placebo, 1.58 (1.40-1.76 mmol/l (p = 0.96. However, a difference was seen at the end of the parallel-group phase: lanthanum carbonate, 1.56 (1.33-1.79 mmol/l; placebo, 2.25 (1.81-2.68 mmol/l (p = 0.0015. There were no clinically important changes in nutritional parameters and no serious treatment-related adverse events were recorded. Conclusions At doses up to 2250 mg/day, lanthanum carbonate is well tolerated and controls hyperphosphatemia effectively. Treatment with higher doses of lanthanum carbonate may allow patients undergoing

The Shark Random Swim - (Lévy Flight with Memory)

Science.gov (United States)

Businger, Silvia

2018-05-01

The Elephant Random Walk (ERW), first introduced by Schütz and Trimper (Phys Rev E 70:045101, 2004), is a one-dimensional simple random walk on Z having a memory about the whole past. We study the Shark Random Swim, a random walk with memory about the whole past, whose steps are α -stable distributed with α \\in (0,2] . Our aim in this work is to study the impact of the heavy tailed step distributions on the asymptotic behavior of the random walk. We shall see that, as for the ERW, the asymptotic behavior of the Shark Random Swim depends on its memory parameter p, and that a phase transition can be observed at the critical value p=1/α.

The dilute random field Ising model by finite cluster approximation

International Nuclear Information System (INIS)

Benyoussef, A.; Saber, M.

1987-09-01

Using the finite cluster approximation, phase diagrams of bond and site diluted three-dimensional simple cubic Ising models with a random field have been determined. The resulting phase diagrams have the same general features for both bond and site dilution. (author). 7 refs, 4 figs

A randomized, double-blind, cross-over, phase IV trial of oros-methylphenidate (CONCERTA(®)) and generic novo-methylphenidate ER-C (NOVO-generic).

Science.gov (United States)

Fallu, Angelo; Dabouz, Farida; Furtado, Melissa; Anand, Leena; Katzman, Martin A

2016-08-01

Attention-deficit/hyperactivity disorder (ADHD) is a common neurobehavioral disorder with onset during childhood. Multiple aspects of a child's development are hindered, in both home and school settings, with negative impacts on social, emotional, and cognitive functioning. If left untreated, ADHD is commonly associated with poor academic achievement and low occupational status, as well as increased risk of substance abuse and delinquency. The objective of this study was to evaluate adult ADHD subject reported outcomes when switched from a stable dose of CONCERTA(®) to the same dose of generic Novo-methylphenidate ER-C(®). Randomized, double-blind, cross-over, phase IV trial consisted of two phases in which participants with a primary diagnosis of ADHD were randomized in a 1:1 ratio to 3 weeks of treatment with CONCERTA or generic Novo-Methylphenidate ER-C. Following 3 weeks of treatment, participants were crossed-over to receive the other treatment for an additional 3 weeks. Primary efficacy was assessed through the use of the Treatment Satisfaction Questionnaire for Medication, Version II (TSQM-II). Participants with ADHD treated with CONCERTA were more satisfied in terms of efficacy and side effects compared to those receiving an equivalent dose of generic Novo-Methylphenidate ER-C. All participants chose to continue with CONCERTA treatment at the conclusion of the study. Although CONCERTA and generic Novo-Methylphenidate ER-C have been deemed bioequivalent, however the present findings demonstrate clinically and statistically significant differences between generic and branded CONCERTA. Further investigation of these differences is warranted.

Once-weekly versus every-other-day stereotactic body radiotherapy in patients with prostate cancer (PATRIOT): A phase 2 randomized trial.

Science.gov (United States)

Quon, Harvey C; Ong, Aldrich; Cheung, Patrick; Chu, William; Chung, Hans T; Vesprini, Danny; Chowdhury, Amit; Panjwani, Dilip; Pang, Geordi; Korol, Renee; Davidson, Melanie; Ravi, Ananth; McCurdy, Boyd; Zhang, Liying; Mamedov, Alexandre; Deabreu, Andrea; Loblaw, Andrew

2018-05-01

Prostate stereotactic body radiotherapy (SBRT) regimens differ in time, dose, and fractionation. We completed a multicentre, randomized phase II study to investigate the impact of overall treatment time on quality of life (QOL). Men with low and intermediate-risk prostate cancer were randomly assigned to 40 Gy in 5 fractions delivered once per week (QW) vs. every other day (EOD). QOL was assessed using the Expanded Prostate Cancer Index Composite. The primary endpoint was the proportion with a minimum clinically important change (MCIC) in bowel QOL during the acute (≤12 week) period, and analysis was by intention-to-treat. ClinicalTrials.gov NCT01423474. 152 men from 3 centres were randomized with median follow-up of 47 months. Patients treated QW had superior acute bowel QOL with 47/69 (68%) reporting a MCIC compared to 63/70 (90%) treated EOD (p = 0.002). Fewer patients treated QW reported moderate-severe problems with bowel QOL during the acute period compared with EOD (14/70 [20%] vs. 40/70 [57%], p < 0.001). Acute urinary QOL was also better in the QW arm, with 52/67 (78%) vs 65/69 (94%) experiencing a MCIC (p = 0.006). There were no significant differences in late urinary or bowel QOL at 2 years or last follow-up. Prostate SBRT delivered QW improved acute bowel and urinary QOL compared to EOD. Patients should be counselled regarding the potential for reduced short-term toxicity and improved QOL with QW prostate SBRT. Copyright © 2018 Elsevier B.V. All rights reserved.

Entanglement dynamics in critical random quantum Ising chain with perturbations

Energy Technology Data Exchange (ETDEWEB)

Huang, Yichen, E-mail: ychuang@caltech.edu

2017-05-15

We simulate the entanglement dynamics in a critical random quantum Ising chain with generic perturbations using the time-evolving block decimation algorithm. Starting from a product state, we observe super-logarithmic growth of entanglement entropy with time. The numerical result is consistent with the analytical prediction of Vosk and Altman using a real-space renormalization group technique. - Highlights: • We study the dynamical quantum phase transition between many-body localized phases. • We simulate the dynamics of a very long random spin chain with matrix product states. • We observe numerically super-logarithmic growth of entanglement entropy with time.

The quantum transverse spin-2 Ising model with a bimodal random-field in the pair approximation

International Nuclear Information System (INIS)

Canko, O.; Albayrak, E.; Keskin, M.

2005-01-01

In this paper, we have investigated the bimodal random-field spin-2 Ising system in a transverse field by combining the pair approximation with the discretized path-integral representation. The exact equations for the second-order phase transition lines and tricritical points are obtained in terms of the random field H, the transverse field G and the coordination number z. It is found that there are some critical values for H and G where the tricritical points disappear for given z. We have also observed that the system presents reentrant behavior which may be caused by the quantum effects and randomness. The phase diagram with respect to the random field and the second-order phase transition temperature are studied extensively for given values of the transverse field and the coordination number

Steganographic optical image encryption system based on reversible data hiding and double random phase encoding

Science.gov (United States)

Chuang, Cheng-Hung; Chen, Yen-Lin

2013-02-01

This study presents a steganographic optical image encryption system based on reversible data hiding and double random phase encoding (DRPE) techniques. Conventional optical image encryption systems can securely transmit valuable images using an encryption method for possible application in optical transmission systems. The steganographic optical image encryption system based on the DRPE technique has been investigated to hide secret data in encrypted images. However, the DRPE techniques vulnerable to attacks and many of the data hiding methods in the DRPE system can distort the decrypted images. The proposed system, based on reversible data hiding, uses a JBIG2 compression scheme to achieve lossless decrypted image quality and perform a prior encryption process. Thus, the DRPE technique enables a more secured optical encryption process. The proposed method extracts and compresses the bit planes of the original image using the lossless JBIG2 technique. The secret data are embedded in the remaining storage space. The RSA algorithm can cipher the compressed binary bits and secret data for advanced security. Experimental results show that the proposed system achieves a high data embedding capacity and lossless reconstruction of the original images.

Dielectric Matrix Formulation of Correlation Energies in the Random Phase Approximation: Inclusion of Exchange Effects.

Science.gov (United States)

Mussard, Bastien; Rocca, Dario; Jansen, Georg; Ángyán, János G

2016-05-10

Starting from the general expression for the ground state correlation energy in the adiabatic-connection fluctuation-dissipation theorem (ACFDT) framework, it is shown that the dielectric matrix formulation, which is usually applied to calculate the direct random phase approximation (dRPA) correlation energy, can be used for alternative RPA expressions including exchange effects. Within this famework, the ACFDT analog of the second order screened exchange (SOSEX) approximation leads to a logarithmic formula for the correlation energy similar to the direct RPA expression. Alternatively, the contribution of the exchange can be included in the kernel used to evaluate the response functions. In this case, the use of an approximate kernel is crucial to simplify the formalism and to obtain a correlation energy in logarithmic form. Technical details of the implementation of these methods are discussed, and it is shown that one can take advantage of density fitting or Cholesky decomposition techniques to improve the computational efficiency; a discussion on the numerical quadrature made on the frequency variable is also provided. A series of test calculations on atomic correlation energies and molecular reaction energies shows that exchange effects are instrumental for improvement over direct RPA results.

Early-stage squamous cell carcinoma of the oropharynx: Radiotherapy vs. Trans-Oral Robotic Surgery (ORATOR) – study protocol for a randomized phase II trial

International Nuclear Information System (INIS)

Nichols, Anthony C; Kuruvilla, Sara; Chen, Jeff; Corsten, Martin; Odell, Michael; Eapen, Libni; Theurer, Julie; Doyle, Philip C; Wehrli, Bret; Kwan, Keith; Palma, David A; Yoo, John; Hammond, J Alex; Fung, Kevin; Winquist, Eric; Read, Nancy; Venkatesan, Varagur; MacNeil, S Danielle; Ernst, D Scott

2013-01-01

The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has markedly increased over the last three decades due to newly found associations with human papillomavirus (HPV) infection. Primary radiotherapy (RT) is the treatment of choice for OPSCC at most centers, and over the last decade, the addition of concurrent chemotherapy has led to a significant improvement in survival, but at the cost of increased acute and late toxicity. Transoral robotic surgery (TORS) has emerged as a promising alternative treatment, with preliminary case series demonstrating encouraging oncologic, functional, and quality of life (QOL) outcomes. However, comparisons of TORS and RT in a non-randomized fashion are susceptible to bias. The goal of this randomized phase II study is to compare QOL, functional outcomes, toxicity profiles, and survival following primary RT (± chemotherapy) vs. TORS (± adjuvant [chemo] RT) in patients with OPSCC. The target patient population comprises OPSCC patients who would be unlikely to require chemotherapy post-resection: Tumor stage T1-T2 with likely negative margins at surgery; Nodal stage N0-2, ≤3 cm in size, with no evidence of extranodal extension on imaging. Participants will be randomized in a 1:1 ratio between Arm 1 (RT ± chemotherapy) and Arm 2 (TORS ± adjuvant [chemo] RT). In Arm 1, patients with N0 disease will receive RT alone, whereas N1-2 patients will receive concurrent chemoradiation. In Arm 2, patients will undergo TORS along with selective neck dissections, which may be staged. Pathologic high-risk features will be used to determine the requirement for adjuvant radiotherapy +/- chemotherapy. The primary endpoint is QOL score using the M.D. Anderson Dysphagia Inventory (MDADI), with secondary endpoints including survival, toxicity, other QOL outcomes, and swallowing function. A sample of 68 patients is required. This study, if successful, will provide a much-needed randomized comparison of the conventional strategy of primary RT

Enhancing evidence-based diabetes and chronic disease control among local health departments: a multi-phase dissemination study with a stepped-wedge cluster randomized trial component.

Science.gov (United States)

Parks, Renee G; Tabak, Rachel G; Allen, Peg; Baker, Elizabeth A; Stamatakis, Katherine A; Poehler, Allison R; Yan, Yan; Chin, Marshall H; Harris, Jenine K; Dobbins, Maureen; Brownson, Ross C

2017-10-18

The rates of diabetes and prediabetes in the USA are growing, significantly impacting the quality and length of life of those diagnosed and financially burdening society. Premature death and disability can be prevented through implementation of evidence-based programs and policies (EBPPs). Local health departments (LHDs) are uniquely positioned to implement diabetes control EBPPs because of their knowledge of, and focus on, community-level needs, contexts, and resources. There is a significant gap, however, between known diabetes control EBPPs and actual diabetes control activities conducted by LHDs. The purpose of this study is to determine how best to support the use of evidence-based public health for diabetes (and related chronic diseases) control among local-level public health practitioners. This paper describes the methods for a two-phase study with a stepped-wedge cluster randomized trial that will evaluate dissemination strategies to increase the uptake of public health knowledge and EBPPs for diabetes control among LHDs. Phase 1 includes development of measures to assess practitioner views on and organizational supports for evidence-based public health, data collection using a national online survey of LHD chronic disease practitioners, and a needs assessment of factors influencing the uptake of diabetes control EBPPs among LHDs within one state in the USA. Phase 2 involves conducting a stepped-wedge cluster randomized trial to assess effectiveness of dissemination strategies with local-level practitioners at LHDs to enhance capacity and organizational support for evidence-based diabetes prevention and control. Twelve LHDs will be selected and randomly assigned to one of the three groups that cross over from usual practice to receive the intervention (dissemination) strategies at 8-month intervals; the intervention duration for groups ranges from 8 to 24 months. Intervention (dissemination) strategies may include multi-day in-person workshops, electronic

Gefitinib plus cisplatin and radiotherapy in previously untreated head and neck squamous cell carcinoma: A phase II, randomized, double-blind, placebo-controlled study

International Nuclear Information System (INIS)

Gregoire, Vincent; Hamoir, Marc; Chen Changhu; Kane, Madeleine; Kawecki, Andrzej; Julka, Pramod K.; Wang, Hung-Ming; Prasad, Srihari; D'Cruz, Anil K.; Radosevic-Jelic, Ljiljana; Kumar, Rejnish R.; Korzeniowski, Stanislaw; Fijuth, Jacek; Machiels, Jean-Pascal; Sellers, Mark V.; Tchakov, Ilian; Raben, David

2011-01-01

Background and purpose: To assess the efficacy and safety of gefitinib given concomitantly and/or as maintenance therapy to standard cisplatin/radiotherapy for previously untreated, unresected, stage III/IV non-metastatic SCCHN. Materials and methods: In this phase II, double-blind, study, 226 patients were randomized to gefitinib 250 mg/day, 500 mg/day or placebo in two phases: a concomitant phase (gefitinib or placebo with chemoradiotherapy), followed by a maintenance phase (gefitinib or placebo alone). Primary endpoint was local disease control rate (LDCR) at 2 years; secondary endpoints were LDCR at 1 year, objective response rate, progression-free survival, overall survival, and safety and tolerability. Results: Gefitinib (250 and 500 mg/day) did not improve 2-year LDCR compared with placebo either when given concomitantly with chemoradiotherapy (32.7% vs. 33.6%, respectively; OR 0.921, 95% CI 0.508, 1.670 [1-sided p = 0.607]) or as maintenance therapy (28.8% vs. 37.4%, respectively; OR 0.684, 95% CI 0.377, 1.241 [1-sided p = 0.894]). Secondary efficacy outcomes were broadly consistent with the 2-year LDCR results. In both doses, gefitinib was well-tolerated and did not adversely affect the safety and tolerability of concomitant chemoradiotherapy. Conclusion: Gefitinib was well-tolerated, but did not improve efficacy compared with placebo when given concomitantly with chemoradiotherapy, or as maintenance therapy alone.

Cryptanalysis and improvement of an optical image encryption scheme using a chaotic Baker map and double random phase encoding

International Nuclear Information System (INIS)

Chen, Jun-Xin; Fu, Chong; Zhu, Zhi-Liang; Zhang, Li-Bo; Zhang, Yushu

2014-01-01

In this paper, we evaluate the security of an enhanced double random phase encoding (DRPE) image encryption scheme (2013 J. Lightwave Technol. 31 2533). The original system employs a chaotic Baker map prior to DRPE to provide more protection to the plain image and hence promote the security level of DRPE, as claimed. However, cryptanalysis shows that this scheme is vulnerable to a chosen-plaintext attack, and the ciphertext can be precisely recovered. The corresponding improvement is subsequently reported upon the basic premise that no extra equipment or computational complexity is required. The simulation results and security analyses prove its effectiveness and security. The proposed achievements are suitable for all cryptosystems under permutation and, following that, the DRPE architecture, and we hope that our work can motivate the further research on optical image encryption. (paper)

Cryptanalysis and improvement of an optical image encryption scheme using a chaotic Baker map and double random phase encoding

Science.gov (United States)

Chen, Jun-Xin; Zhu, Zhi-Liang; Fu, Chong; Zhang, Li-Bo; Zhang, Yushu

2014-12-01

In this paper, we evaluate the security of an enhanced double random phase encoding (DRPE) image encryption scheme (2013 J. Lightwave Technol. 31 2533). The original system employs a chaotic Baker map prior to DRPE to provide more protection to the plain image and hence promote the security level of DRPE, as claimed. However, cryptanalysis shows that this scheme is vulnerable to a chosen-plaintext attack, and the ciphertext can be precisely recovered. The corresponding improvement is subsequently reported upon the basic premise that no extra equipment or computational complexity is required. The simulation results and security analyses prove its effectiveness and security. The proposed achievements are suitable for all cryptosystems under permutation and, following that, the DRPE architecture, and we hope that our work can motivate the further research on optical image encryption.

Lowest lying 2+ and 3- vibrational states in Pb, Sn, and Ni isotopes in relativistic quasiparticle random-phase approximation

International Nuclear Information System (INIS)

Ansari, A.; Ring, P.

2006-01-01

The excitation energies and electric multipole decay rates of the lowest lying 2 + and 3 - vibrational states in Pb, Sn, and Ni nuclei are calculated following relativistic quasiparticle random-phase approximation formalism based on the relativistic Hartree-Bogoliubov mean field. Two sets of Lagrangian parameters, NL1 and NL3, are used to investigate the effect of the nuclear force. Overall there is good agreement with the available experimental data for a wide range of mass numbers considered here, and the NL3 set seems to be a better choice. However, strictly speaking, these studies point toward the need of a new set of force parameters that could produce more realistic single-particle levels, at least in vicinity of the Fermi surface, of a wide range of nuclear masses

Efficacy and Safety of Axitinib Versus Sorafenib in Metastatic Renal Cell Carcinoma: Subgroup Analysis of Japanese Patients from the Global Randomized Phase 3 AXIS Trial

OpenAIRE

Ueda, Takeshi; Uemura, Hirotsugu; Tomita, Yoshihiko; Tsukamoto, Taiji; Kanayama, Hiroomi; Shinohara, Nobuo; Tarazi, Jamal; Chen, Connie; Kim, Sinil; Ozono, Seiichiro; Naito, Seiji; Akaza, Hideyuki

2013-01-01

Objective Axitinib is a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2 and 3. The efficacy and safety of axitinib in Japanese patients with metastatic renal cell carcinoma were evaluated. Methods A subgroup analysis was conducted in Japanese patients enrolled in the randomized Phase III trial of axitinib versus sorafenib after failure of one prior systemic therapy for metastatic renal cell carcinoma. Results Twenty-five (of 361) and 29 (o...

Random model of two-level atoms interacting with electromagnetic field

International Nuclear Information System (INIS)

Kireev, A.N.; Meleshko, A.N.

1983-12-01

A phase transition has been studied in a random system of two-level atoms interacting with an electromagnetic field. It is shown that superradiation can arise when there is short-range order in a spin-subsystem. The existence of long-range order is irrelevant for this phase transition

Phase-space networks of geometrically frustrated systems.

Science.gov (United States)

Han, Yilong

2009-11-01

We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

Random-start ovarian stimulation in women desiring elective cryopreservation of oocytes.

Science.gov (United States)

Pereira, Nigel; Voskuilen-Gonzalez, Anna; Hancock, Kolbe; Lekovich, Jovana P; Schattman, Glenn L; Rosenwaks, Zev

2017-10-01

The current study investigates the utility of random-start ovarian stimulation in women desiring elective oocyte cryopreservation. Women in the study cohort underwent random-start ovarian stimulation, and were subdivided based on the phase of the menstrual cycle that ovarian stimulation began, i.e. early follicular, late follicular or luteal phase. Women undergoing conventional cycle day (CD) 2/3 ovarian stimulation start were controls. A total of 1302 women were included - 859 (66.0%) conventional CD 2/3, 342 (26.3%) early follicular, 42 (3.2%) late follicular and 59 (4.5%) luteal ovarian stimulation starts. There was no difference in the demographics or baseline ovarian stimulation characteristics. The duration of ovarian stimulation (11 versus 9 days; P start group. The number of total and MII oocytes in the control and random-start groups was similar. A non-significant trend towards increased cycle cancellation was noted in the late follicular start group (7.1%). Study findings indicate the number of total and MII oocytes derived from random-start protocols initiated during any phase of the menstrual cycle is similar to conventional CD 2/3 ovarian stimulation start protocols in women desiring elective oocyte cryopreservation. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Detecting phase transitions in a neural network and its application to classification of syndromes in traditional Chinese medicine

Energy Technology Data Exchange (ETDEWEB)

Chen, J; Xi, G [Key Laboratory of Complex Systems and Intelligence Science, Institute of Automation, Chinese Academy of Sciences, 100080, Beijing (China); Wang, W [Beijing University of Chinese Medicine, 100029, Beijing (China)], E-mail: guangcheng.xi@ia.ac.cn

2008-02-15

Detecting phase transitions in neural networks (determined or random) presents a challenging subject for phase transitions play a key role in human brain activity. In this paper, we detect numerically phase transitions in two types of random neural network(RNN) under proper parameters.

(Non-) Gibbsianness and Phase Transitions in Random Lattice Spin Models

NARCIS (Netherlands)

Külske, C.

1999-01-01

We consider disordered lattice spin models with finite-volume Gibbs measures µΛ[η](dσ). Here σ denotes a lattice spin variable and η a lattice random variable with product distribution P describing the quenched disorder of the model. We ask: when will the joint measures limΛ↑Zd P(dη)µΛ[η](dσ) be

Safety and immunogenicity of inactivated poliovirus vaccine made from Sabin strains: a phase II, randomized, positive-controlled trial.

Science.gov (United States)

Liao, Guoyang; Li, Rongcheng; Li, Changgui; Sun, Mingbo; Li, Yanping; Chu, Jiayou; Jiang, Shude; Li, Qihan

2012-01-15

The production of Sabin inactivated poliovirus vaccine (IPV) can reduce biosafety requirements in the posteradication/post-oral poliovirus vaccine (OPV) era. We conducted a phase II, randomized, positive-controlled trial to assess the safety and immunogenicity of Sabin IPV. The test groups (A, B, and C) received 3 doses of high, middle, and low D antigen (D Ag) of Sabin IPV at ages 2, 3, and 4 months, respectively. Infants in 2 control groups, group D and group E, received 3 doses of trivalent OPV and conventional IPV (cIPV), respectively, on the same schedule as that of groups A, B, and C. Serum samples were collected before and 30 days after the administration of the third dose. In total, 500 infants were randomly assigned to 5 groups, and 449 infants completed the vaccine series. No serious adverse events were associated with vaccinations. After 3 doses, the seroconversion rates in groups A, B, C, D, and E were 100%, 97.8%, 96.6%, 100%, and 90.1%, respectively, for type 1 poliovirus; 97.7%, 95.7%, 78.7%, 100%, and 90.1%, respectively, for type 2; and 98.8%, 98.9%, 93.3%, 100%, and 97.8%, respectively, for type 3. Sabin IPV has good safety characteristics. The seroconversion rates for type 1 poliovirus (most appropriate concentration, 15 D Ag units [DU]), type 2 (32 DU), and type 3 (45 DU) Sabin IPV were similar to those of the OPV and cIPV control groups. NCT01056705.

Phase-change drywalls in a passive-solar building

Energy Technology Data Exchange (ETDEWEB)

Darkwa, K.; O' Callaghan, P.W.; Tetlow, D. [School of the Built Environment, The Applied Energy and Environmental Engineering Group, Nottingham Trent University, Burton Street, Nottingham NG1 4BU (United Kingdom)

2006-05-15

Integration of phase-change materials (PCMs) into building fabrics is considered to be one of the potential and effective ways of minimising energy-consumption and CO{sub 2}-emissions in the building sector. In order to assess the thermal effectiveness of this concept, composite PCM drywall samples (i.e., randomly mixed and laminated PCM drywalls) have been evaluated in a model passive-solar building. For a broader assessment, the effects of three phase-change zones (narrow, intermediate and wide) of the PCM sample were considered. The results showed that the laminated PCM sample with a narrow phase-change zone was capable of increasing the minimum room temperature by about 17% more than the randomly mixed type. Even though there was some display of a non-isothermal phase-change process, the laminated system proved to be thermally more effective in terms of evolution and utilisation of latent heat. A further heat-transfer enhancement process is, however, required for the development of the laminated system. . (author)

A Randomized Controlled Trial of Cognitive-Behavior Therapy Plus Bright Light Therapy for Adolescent Delayed Sleep Phase Disorder

Science.gov (United States)

Gradisar, Michael; Dohnt, Hayley; Gardner, Greg; Paine, Sarah; Starkey, Karina; Menne, Annemarie; Slater, Amy; Wright, Helen; Hudson, Jennifer L.; Weaver, Edward; Trenowden, Sophie

2011-01-01

Objective: To evaluate cognitive-behavior therapy plus bright light therapy (CBT plus BLT) for adolescents diagnosed with delayed sleep phase disorder (DSPD). Design: Randomized controlled trial of CBT plus BLT vs. waitlist (WL) control with comparisons at pre- and post-treatment. There was 6-month follow-up for the CBT plus BLT group only. Setting: Flinders University Child & Adolescent Sleep Clinic, Adelaide, South Australia. Patients: 49 adolescents (mean age 14.6 ± 1.0 y, 53% males) diagnosed with DSPD; mean chronicity 4 y 8 months; 16% not attending school. Eighteen percent of adolescents dropped out of the study (CBT plus BLT: N = 23 vs WL: N = 17). Interventions: CBT plus BLT consisted of 6 individual sessions, including morning bright light therapy to advance adolescents' circadian rhythms, and cognitive restructuring and sleep education to target associated insomnia and sleep hygiene. Measurements and Results: DSPD diagnosis was performed via a clinical interview and 7-day sleep diary. Measurements at each time-point included online sleep diaries and scales measuring sleepiness, fatigue, and depression symptoms. Compared to WL, moderate-to-large improvements (d = 0.65-1.24) were found at post-treatment for CBT plus BLT adolescents, including reduced sleep latency, earlier sleep onset and rise times, total sleep time (school nights), wake after sleep onset, sleepiness, and fatigue. At 6-month follow-up (N = 15), small-to-large improvements (d = 0.24-1.53) continued for CBT plus BLT adolescents, with effects found for all measures. Significantly fewer adolescents receiving CBT plus BLT met DPSD criteria at post-treatment (WL = 82% vs. CBT plus BLT = 13%, P sleep and daytime impairments in the immediate and long-term. Studies evaluating the treatment effectiveness of each treatment component are needed. Clinical Trial Information: Australia – New Zealand Trials Registry Number: ACTRN12610001041044. Citation: Gradisar M; Dohnt H; Gardner G; Paine S; Starkey

Experimental study of a quantum random-number generator based on two independent lasers

Science.gov (United States)

Sun, Shi-Hai; Xu, Feihu

2017-12-01

A quantum random-number generator (QRNG) can produce true randomness by utilizing the inherent probabilistic nature of quantum mechanics. Recently, the spontaneous-emission quantum phase noise of the laser has been widely deployed for quantum random-number generation, due to its high rate, its low cost, and the feasibility of chip-scale integration. Here, we perform a comprehensive experimental study of a phase-noise-based QRNG with two independent lasers, each of which operates in either continuous-wave (CW) or pulsed mode. We implement the QRNG by operating the two lasers in three configurations, namely, CW + CW, CW + pulsed, and pulsed + pulsed, and demonstrate their trade-offs, strengths, and weaknesses.

A randomized phase II chemoprevention trial of 13-CIS retinoic acid with or without alpha tocopherol or observation in subjects at high risk for lung cancer.

Science.gov (United States)

Kelly, Karen; Kittelson, John; Franklin, Wilbur A; Kennedy, Timothy C; Klein, Catherine E; Keith, Robert L; Dempsey, Edward C; Lewis, Marina; Jackson, Mary K; Hirsch, Fred R; Bunn, Paul A; Miller, York E

2009-05-01

No chemoprevention strategies have been proven effective for lung cancer. We evaluated the effect of 13-cis retinoic acid (13-cis RA), with or without alpha tocopherol, as a lung cancer chemoprevention agent in a phase II randomized controlled clinical trial of adult subjects at high risk for lung cancer as defined by the presence of sputum atypia, history of smoking, and airflow obstruction, or a prior surgically cured nonsmall cell lung cancer (disease free, >3 years). Subjects were randomly assigned to receive either 13-cis RA, 13-cis RA plus alpha tocopherol (13-cis RA/alpha toco) or observation for 12 months. Outcome measures are derived from histologic evaluation of bronchial biopsy specimens obtained by bronchoscopy at baseline and follow-up. The primary outcome measure is treatment "failure" defined as histologic progression (any increase in the maximum histologic score) or failure to return for follow-up bronchoscopy. Seventy-five subjects were randomized (27/22/26 to observations/13-cis RA/13-cis RA/alpha toco); 59 completed the trial; 55 had both baseline and follow-up bronchoscopy. The risk of treatment failure was 55.6% (15 of 27) and 50% (24 of 48) in the observation and combined (13 cis RA plus 13 cis RA/alpha toco) treatment arms, respectively (odds ratio adjusted for baseline histology, 0.97; 95% confidence interval, 0.36-2.66; P = 0.95). Among subjects with complete histology data, maximum histology score in the observation arm increased by 0.37 units and by 0.03 units in the treated arms (difference adjusted for baseline, -0.18; 95% confidence interval, -1.16 to 0.81; P = 0.72). Similar (nonsignificant) results were observed for treatment effects on endobronchial proliferation as assessed by Ki-67 immunolabeling. Twelve-month treatment with 13-cis RA produced nonsignificant changes in bronchial histology, consistent with results in other trials. Agents advancing to phase III randomized trials should produce greater histologic changes. The

A Randomized Phase II Chemoprevention Trial of 13-CIS Retinoic Acid with Or without α Tocopherol or Observation in Subjects at High Risk for Lung Cancer

Science.gov (United States)

Kelly, Karen; Kittelson, John; Franklin, Wilbur A.; Kennedy, Timothy C.; Klein, Catherine E.; Keith, Robert L.; Dempsey, Edward C.; Lewis, Marina; Jackson, Mary K.; Hirsch, Fred R.; Bunn, Paul A.; Miller, York E.

2011-01-01

No chemoprevention strategies have been proven effective for lung cancer. We evaluated the effect of 13-cis retinoic acid (13-cis RA), with or without α tocopherol, as a lung cancer chemoprevention agent in a phase II randomized controlled clinical trial of adult subjects at high risk for lung cancer as defined by the presence of sputum atypia, history of smoking, and airflow obstruction, or a prior surgically cured nonsmall cell lung cancer (disease free, >3 years). Subjects were randomly assigned to receive either 13-cis RA, 13-cis RA plus α tocopherol (13-cis RA/α toco) or observation for 12 months. Outcome measures are derived from histologic evaluation of bronchial biopsy specimens obtained by bronchoscopy at baseline and follow-up. The primary outcome measure is treatment “failure” defined as histologic progression (any increase in the maximum histologic score) or failure to return for follow-up bronchoscopy. Seventy-five subjects were randomized (27/22/26 to obervations/13-cis RA/13-cis RA/α toco); 59 completed the trial; 55 had both baseline and follow-up bronchoscopy. The risk of treatment failure was 55.6% (15 of 27) and 50% (24 of 48) in the observation and combined (13 cis RA plus 13 cis RA/α toco) treatment arms, respectively (odds ratio adjusted for baseline histology, 0.97; 95% confidence interval, 0.36–2.66; P = 0.95). Among subjects with complete histology data, maximum histology score in the observation arm increased by 0.37 units and by 0.03 units in the treated arms (difference adjusted for baseline, −0.18; 95% confidence interval, −1.16 to 0.81; P = 0.72). Similar (nonsignificant) results were observed for treatment effects on endobronchial proliferation as assessed by Ki-67 immunolabeling. Twelve-month treatment with 13-cis RA produced nonsignificant changes in bronchial histology, consistent with results in other trials. Agents advancing to phase III randomized trials should produce greater histologic changes. The addition of �

Application of phase-change materials in memory taxonomy

OpenAIRE

Wang, Lei; Tu, Liang; Wen, Jing

2017-01-01

Abstract Phase-change materials are suitable for data storage because they exhibit reversible transitions between crystalline and amorphous states that have distinguishable electrical and optical properties. Consequently, these materials find applications in diverse memory devices ranging from conventional optical discs to emerging nanophotonic devices. Current research efforts are mostly devoted to phase-change random access memory, whereas the applications of phase-change materials in other...

A Phase Ib open label, randomized, safety study of SANGUINATE™ in patients with sickle cell anemia

Directory of Open Access Journals (Sweden)

Hemant Misra

Full Text Available Abstract Background: Treatment of sickle cell anemia is a challenging task and despite the well understood genetic and biochemical pathway of sickle hemoglobin, current therapy continues to be limited to the symptomatic treatment of pain, supplemental oxygen, antibiotics, red blood cell transfusions and hydroxyurea. SANGUINATE is a carbon monoxide releasing molecule and oxygen transfer agent under clinical development for the treatment of sickle cell anemia and comorbidities. Methods: An open-label randomized Phase Ib study was performed in adult sickle cell anemia patients. Two dose levels of SANGUINATE were compared to hydroxyurea in 24 homozygotes for Hb SS. Twelve subjects received either a low dose (160 mg/kg of SANGUINATE or 15 mg/kg hydroxyurea. Another 12 subjects received either a high dose (320 mg/kg of SANGUINATE or 15 mg/kg hydroxyurea. The primary endpoint was the safety of SANGUINATE versus hydroxyurea in sickle cell anemia patients. Secondary endpoints included determination of the plasma pharmacokinetics and assessment of hematologic measurements. Results: Musculoskeletal related adverse events were the most common. Transient troponin I levels increased in three patients, one of whom had an increase in tricuspid regurgitant velocity; however, no clinical signs were noted. Following an assessment of vital signs, tricuspid regurgitant velocity, electrocardiogram, serum biochemistry, hematology, urinalysis, and analysis of reported adverse events, SANGUINATE was found to be safe in stable sickle cell anemia patients. Conclusions: The clinical trial met its primary objective of demonstrating an acceptable safety profile for SANGUINATE in patients with sickle cell anemia. This trial established the safety of SANGUINATE at both dose levels and permitted its advance to Phase II trials.

Phase II randomized trial of neoadjuvant metformin plus letrozole versus placebo plus letrozole for estrogen receptor positive postmenopausal breast cancer (METEOR)

International Nuclear Information System (INIS)

Kim, Jisun; Kim, Lee Su; Han, Sehwan; Nam, Seok Jin; Kang, Han-Sung; Kim, Seung Il; Yoo, Young Bum; Jeong, Joon; Kim, Tae Hyun; Kang, Taewoo; Kim, Sung-Won; Lim, Woosung; Jung, Yongsik; Lee, Jeong Eon; Kim, Ku Sang; Yu, Jong-Han; Chae, Byung Joo; Jung, So-Youn; Kang, Eunyoung; Choi, Su Yun; Moon, Hyeong-Gon; Noh, Dong-Young; Kim, Eun-Kyu; Han, Wonshik; Kim, Min-Kyoon; Paik, Nam-Sun; Jeong, Sang-Seol; Yoon, Jung-han; Park, Chan Heun; Ahn, Sei Hyun

2014-01-01

Neoadjuvant endocrine therapy with an aromatase inhibitor has shown efficacy comparable to that of neoadjuvant chemotherapy in patients with postmenopausal breast cancer. Preclinical and clinical studies have shown that the antidiabetic drug metformin has anti-tumor activity. This prospective, multicenter, phase II randomized, placebo controlled trial was designed to evaluate the direct anti-tumor effect of metformin in non-diabetic postmenopausal women with estrogen-receptor (ER) positive breast cancer. Patients meeting the inclusion criteria and providing written informed consent will be randomized to 24 weeks of neoadjuvant treatment with letrozole (2.5 mg/day) and either metformin (2000 mg/day) or placebo. Target accrual number is 104 patients per arm. The primary endpoint will be clinical response rate, as measured by calipers. Secondary endpoints include pathologic complete response rate, breast conserving rate, change in Ki67 expression, breast density change, and toxicity profile. Molecular assays will be performed using samples obtained before treatment, at week 4, and postoperatively. This study will provide direct evidence of the anti-tumor effect of metformin in non-diabetic, postmenopausal patients with ER-positive breast cancer. ClinicalTrials.gov Identifier http://clinicaltrial.gov/ct2/show/NCT01589367?term

Adalimumab for nail psoriasis: Efficacy and safety from the first 26 weeks of a phase 3, randomized, placebo-controlled trial.

Science.gov (United States)

Elewski, Boni E; Okun, Martin M; Papp, Kim; Baker, Christopher S; Crowley, Jeffrey J; Guillet, Gérard; Sundaram, Murali; Poulin, Yves; Gu, Yihua; Geng, Ziqian; Williams, David A; Rich, Phoebe A

2018-01-01

Previous clinical trials have not evaluated improvement in nail psoriasis as a primary end point. This phase 3 trial evaluated the safety and efficacy of adalimumab in patients with moderate-to-severe fingernail psoriasis and moderate-to-severe plaque psoriasis. Patients were randomized 1:1 to 40 mg adalimumab every other week or placebo. The primary efficacy end point was at least 75% improvement in total-fingernail modified Nail Psoriasis Severity Index (NAPSI75) response rate at week 26. Ranked secondary end point scores evaluated at week 26 were total-fingernail NAPSI and modified NAPSI, nail pain, Nail Psoriasis Physical Functioning Severity, Brigham Scalp Nail Inverse Palmo-Plantar Psoriasis Index, and Physician's Global Assessment (fingernail psoriasis). Of the 217 randomized patients (108 received placebo and 109 received adalimumab), 188 (86.6%) completed 26 weeks of treatment (period A) or escaped early to the open-label period. The study met the primary end point (response rate of 3.4% with placebo vs 46.6% with adalimumab [P psoriasis versus with placebo and no new safety risks were identified. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

5-Fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus sunitinib or bevacizumab as first-line treatment for metastatic colorectal cancer: a randomized Phase IIb study

Science.gov (United States)

Hecht, J Randolph; Mitchell, Edith P; Yoshino, Takayuki; Welslau, Manfred; Lin, Xun; Chow Maneval, Edna; Paolini, Jolanda; Lechuga, Maria Jose; Kretzschmar, Albrecht

2015-01-01

Background Sunitinib is an oral inhibitor of tyrosine kinase receptors implicated in tumor proliferation, angiogenesis, and metastasis. In this randomized, multicenter, open-label Phase IIb study, sunitinib plus mFOLFOX6 (oxaliplatin plus leucovorin plus 5-fluorouracil) was compared with bevacizumab plus mFOLFOX6 as first-line therapy in patients with metastatic colorectal cancer. Methods Patients were stratified by performance status, baseline lactate dehydrogenase level, and prior adjuvant treatment, and randomized 1:1 to receive sunitinib 37.5 mg/day for 4 weeks on and 2 weeks off plus mFOLFOX6 every 2 weeks or bevacizumab 5 mg/kg every 2 weeks plus mFOLFOX6 every 2 weeks. The primary endpoint was progression-free survival. Secondary endpoints included objective response rate, overall survival, safety, and quality of life. Results Enrollment was closed early following accrual of 191 patients, based on an interim analysis showing an inferior trend in the primary progression-free survival efficacy endpoint for sunitinib. Ninety-six patients were randomized to sunitinib plus mFOLFOX6 and 95 to bevacizumab plus mFOLFOX6. Median progression-free survival was 9.3 months and 15.4 months, respectively, but the objective response rate was similar between the study arms. Median overall survival was 23.7 months and 34.1 months, respectively. Dose reductions and interruptions were more common with sunitinib. Hematologic toxicity was more common in the sunitinib arm. Conclusion While the results of the sunitinib arm are comparable with those of previously reported FOLFOX combinations, the sunitinib-based combination was associated with more toxicity than that observed with bevacizumab and mFOLFOX6. The bevacizumab arm had an unexpectedly good outcome, and was much better than that seen in the Phase III trials. Combination therapy with sunitinib plus mFOLFOX6 is not recommended for patients with metastatic colorectal cancer. PMID:26109878

5-Fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus sunitinib or bevacizumab as first-line treatment for metastatic colorectal cancer: a randomized Phase IIb study

International Nuclear Information System (INIS)

Hecht, J Randolph; Mitchell, Edith P; Yoshino, Takayuki; Welslau, Manfred; Lin, Xun; Chow Maneval, Edna; Paolini, Jolanda; Lechuga, Maria Jose; Kretzschmar, Albrecht

2015-01-01

Sunitinib is an oral inhibitor of tyrosine kinase receptors implicated in tumor proliferation, angiogenesis, and metastasis. In this randomized, multicenter, open-label Phase IIb study, sunitinib plus mFOLFOX6 (oxaliplatin plus leucovorin plus 5-fluorouracil) was compared with bevacizumab plus mFOLFOX6 as first-line therapy in patients with metastatic colorectal cancer. Patients were stratified by performance status, baseline lactate dehydrogenase level, and prior adjuvant treatment, and randomized 1:1 to receive sunitinib 37.5 mg/day for 4 weeks on and 2 weeks off plus mFOLFOX6 every 2 weeks or bevacizumab 5 mg/kg every 2 weeks plus mFOLFOX6 every 2 weeks. The primary endpoint was progression-free survival. Secondary endpoints included objective response rate, overall survival, safety, and quality of life. Enrollment was closed early following accrual of 191 patients, based on an interim analysis showing an inferior trend in the primary progression-free survival efficacy endpoint for sunitinib. Ninety-six patients were randomized to sunitinib plus mFOLFOX6 and 95 to bevacizumab plus mFOLFOX6. Median progression-free survival was 9.3 months and 15.4 months, respectively, but the objective response rate was similar between the study arms. Median overall survival was 23.7 months and 34.1 months, respectively. Dose reductions and interruptions were more common with sunitinib. Hematologic toxicity was more common in the sunitinib arm. While the results of the sunitinib arm are comparable with those of previously reported FOLFOX combinations, the sunitinib-based combination was associated with more toxicity than that observed with bevacizumab and mFOLFOX6. The bevacizumab arm had an unexpectedly good outcome, and was much better than that seen in the Phase III trials. Combination therapy with sunitinib plus mFOLFOX6 is not recommended for patients with metastatic colorectal cancer

EFFECT OF SUPERVISED MODERATE INTENSITY EXERCISE PROGRAM IN PHASE ONE CARDIAC REHABILITATION OF POST OPERATIVE CABG PATIENTS - A RANDOMIZED CONTROLLED TRAIL

Directory of Open Access Journals (Sweden)

Rajan Modi

2014-10-01

Full Text Available Background: With the increasing number of cases for CABG, the cardiac rehabilitation has gained importance. The trends in rehabilitation of a coronary artery disease patient are changing by incorporating a variety of aerobic exercises and resisted training in to their rehabilitation program. The outcome of any exercise chiefly depends on the training parameters like intensity, frequency and duration. Hence the present study focused to know the effects of supervised moderate intensity exercises on patients during hospital discharge following CABG. The objective of is to study the effectiveness of supervised moderate intensity exercise on distance walked and Quality of Life at hospital discharge following CABG. Methods: Study recruited randomly 46 patients between age group 40-65 years who were posted for non-emergency CABG for the first time. Pre-operative assessment was done thoroughly and was divided in to two groups, Group A conventional treatment and Group B Moderate intensity exercise group. The patients were treated using different protocols in terms of intensity for 8-10 days immediate post CABG. Then the outcome parameters of 6MWT and sf-36 were compared for analysis. Results: Both groups individually showed extremely significant results for two outcome measures. 6 MWD difference between two treatment groups showed significant results with unpaired t test (t = 8.5720,p<0.001. Quality of life score difference within group showed very significant results but there is no difference found between both groups. Conclusion: Moderate intensity exercises can also be included in the immediate post-operative phase of CABG, as they reduce the length of hospital stay and quicken the cardiac rehabilitation process. But there need to be a lot of randomized control trails to confirm the benefits of moderate intensity exercises in phase one rehabilitation program after CABG.

Nd break-up process with considering 3NF at intermediate energies in a 3D approach

Energy Technology Data Exchange (ETDEWEB)

Radin, M., E-mail: harzchi@kntu.ac.ir; Ghasemi, H.

2016-01-15

In this work we have applied a three-dimensional approach to solve the three-nucleon Faddeev equation in the Jacobi momenta space. To this end, we have considered the inhomogeneous part of the Faddeev equation as an appropriate approximation for projectile intermediate energies. As an application the Bonn-B and the Tucson–Melbourne two- and three-nucleon forces have been used for calculating the differential cross section for proton–deuteron break-up process. Finally, comparing our results with the experimental data has been performed for 197 MeV and 346 MeV projectile energies.

Proton relativistic model; Modelo relativistico do proton

Energy Technology Data Exchange (ETDEWEB)

Araujo, Wilson Roberto Barbosa de

1996-12-31

In this dissertation, we present a model for the nucleon, which is composed by three relativistic quarks interacting through a contract force. The nucleon wave-function was obtained from the Faddeev equation in the null-plane. The covariance of the model under kinematical null-plane boots is discussed. The electric proton form-factor, calculated from the Faddeev wave-function, was in agreement with the data for low-momentum transfers and described qualitatively the asymptotic region for momentum transfers around 2 GeV. (author) 42 refs., 22 figs., 1 tab.

Successful Completion of the Pilot Phase of a Randomized Controlled Trial Comparing Sentinel Lymph Node Biopsy to No Further Axillary Staging in Patients with Clinical T1-T2 N0 Breast Cancer and Normal Axillary Ultrasound.

Science.gov (United States)

Cyr, Amy E; Tucker, Natalia; Ademuyiwa, Foluso; Margenthaler, Julie A; Aft, Rebecca L; Eberlein, Timothy J; Appleton, Catherine M; Zoberi, Imran; Thomas, Maria A; Gao, Feng; Gillanders, William E

2016-08-01

Axillary surgery is not considered therapeutic in patients with clinical T1-T2 N0 breast cancer. The importance of axillary staging is eroding in an era in which tumor biology, as defined by biomarker and gene expression profile, is increasingly important in medical decision making. We hypothesized that axillary ultrasound (AUS) is a noninvasive alternative to sentinel lymph node biopsy (SLNB), and AUS could replace SLNB without compromising patient care. Patients with clinical T1-T2 N0 breast cancer and normal AUS were eligible for enrollment. Subjects were randomized to no further axillary staging (arm 1) vs SLNB (arm 2). Descriptive statistics were used to describe the results of the pilot phase of the randomized controlled trial. Sixty-eight subjects were enrolled in the pilot phase of the trial (34 subjects in arm 1, no further staging; 32 subjects in arm 2, SLNB; and 2 subjects voluntarily withdrew from the trial). The median age was 61 years (range 40 to 80 years) in arm 1 and 59 years (range 31 to 81 years) in arm 2, and there were no significant clinical or pathologic differences between the arms. Median follow-up was 17 months (range 1 to 32 months). The negative predictive value (NPV) of AUS for identification of clinically significant axillary disease (>2.0 mm) was 96.9%. No axillary recurrences have been observed in either arm. Successful completion of the pilot phase of the randomized controlled trial confirms the feasibility of the study design, and provides prospective evidence supporting the ability of AUS to exclude clinically significant disease in the axilla. The results provide strong support for a phase 2 randomized controlled trial. Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Phase diagram of the disordered Bose-Hubbard model

International Nuclear Information System (INIS)

Gurarie, V.; Pollet, L.; Prokof'ev, N. V.; Svistunov, B. V.; Troyer, M.

2009-01-01

We establish the phase diagram of the disordered three-dimensional Bose-Hubbard model at unity filling which has been controversial for many years. The theorem of inclusions, proven by Pollet et al. [Phys. Rev. Lett. 103, 140402 (2009)] states that the Bose-glass phase always intervenes between the Mott insulating and superfluid phases. Here, we note that assumptions on which the theorem is based exclude phase transitions between gapped (Mott insulator) and gapless phases (Bose glass). The apparent paradox is resolved through a unique mechanism: such transitions have to be of the Griffiths type when the vanishing of the gap at the critical point is due to a zero concentration of rare regions where extreme fluctuations of disorder mimic a regular gapless system. An exactly solvable random transverse field Ising model in one dimension is used to illustrate the point. A highly nontrivial overall shape of the phase diagram is revealed with the worm algorithm. The phase diagram features a long superfluid finger at strong disorder and on-site interaction. Moreover, bosonic superfluidity is extremely robust against disorder in a broad range of interaction parameters; it persists in random potentials nearly 50 (!) times larger than the particle half-bandwidth. Finally, we comment on the feasibility of obtaining this phase diagram in cold-atom experiments, which work with trapped systems at finite temperature.

Renormalization-group study of superfluidity and phase separation of helium mixtures immersed in a disordered porous medium

International Nuclear Information System (INIS)

Lopatnikova, A.; Berker, A.N.

1997-01-01

Superfluidity and phase separation in 3 He- 4 He mixtures immersed in aerogel are studied by renormalization-group theory. The quenched disorder imposed by aerogel, both at the atomic level and at the geometric level, is included. The calculation is conducted via the coupled renormalization-group mappings, near and away from aerogel, of the quenched probability distributions of random interactions. Random-bond effects on the onset of superfluidity and random-field effects on superfluid-superfluid phase separation are seen. The quenched randomness causes the λ line of second-order phase transitions of superfluidity onset to reach zero temperature, in agreement with general predictions and experiments. The effects of the atomic and geometric randomness of aerogel are investigated separately and jointly. copyright 1997 The American Physical Society

Chalcogenides Metastability and Phase Change Phenomena

CERN Document Server

Kolobov, Alexander V

2012-01-01

A state-of-the-art description of metastability observed in chalcogenide alloys is presented with the accent on the underlying physics. A comparison is made between sulphur(selenium)-based chalcogenide glasses, where numerous photo-induced phenomena take place entirely within the amorphous phase, and tellurides where a reversible crystal-to-amorphous phase-change transformation is a major effect. Applications of metastability in devices¿optical memories and nonvolatile electronic phase-change random-access memories among others are discussed, including the latest trends. Background material essential for understanding current research in the field is also provided.

Structural phase transitions and Huang scattering

International Nuclear Information System (INIS)

Yamada, Yasusada

1980-01-01

The usefulness of the application of the concept of Huang scattering to the understandings of the origin of diffuse scatterings near structural phase transitions are discussed. It is pointed out that in several phase transitions, the observed diffuse scatterings can not be interpreted in terms of critical fluctuations of the order parameters associated with the structural phase transitions, and that they are rather interpreted as Huang scattering due to random distribution of individual order parameter which is 'dressed' by strain fields. Examples to show effective applications of this concept to analyze the experimental X-ray data and whence to understand microscopic mechanisms of structural phase transitions are presented. (author)

Random matrix analysis of the QCD sign problem for general topology

International Nuclear Information System (INIS)

Bloch, Jacques; Wettig, Tilo

2009-01-01

Motivated by the important role played by the phase of the fermion determinant in the investigation of the sign problem in lattice QCD at nonzero baryon density, we derive an analytical formula for the average phase factor of the fermion determinant for general topology in the microscopic limit of chiral random matrix theory at nonzero chemical potential, for both the quenched and the unquenched case. The formula is a nontrivial extension of the expression for zero topology derived earlier by Splittorff and Verbaarschot. Our analytical predictions are verified by detailed numerical random matrix simulations of the quenched theory.

Coherent diffractive imaging using randomly coded masks

Energy Technology Data Exchange (ETDEWEB)

Seaberg, Matthew H., E-mail: seaberg@slac.stanford.edu [CNRS and D.I., UMR 8548, École Normale Supérieure, 45 Rue d' Ulm, 75005 Paris (France); Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); D' Aspremont, Alexandre [CNRS and D.I., UMR 8548, École Normale Supérieure, 45 Rue d' Ulm, 75005 Paris (France); Turner, Joshua J. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

2015-12-07

We experimentally demonstrate an extension to coherent diffractive imaging that encodes additional information through the use of a series of randomly coded masks, removing the need for typical object-domain constraints while guaranteeing a unique solution to the phase retrieval problem. Phase retrieval is performed using a numerical convex relaxation routine known as “PhaseCut,” an iterative algorithm known for its stability and for its ability to find the global solution, which can be found efficiently and which is robust to noise. The experiment is performed using a laser diode at 532.2 nm, enabling rapid prototyping for future X-ray synchrotron and even free electron laser experiments.

Phase I Randomized Study of a Tetravalent Dengue Purified Inactivated Vaccine in Healthy Adults from Puerto Rico.

Science.gov (United States)

Diaz, Clemente; Lin, Leyi; Martinez, Luis J; Eckels, Kenneth H; Campos, Maribel; Jarman, Richard G; De La Barrera, Rafael; Lepine, Edith; Toussaint, Jean-François; Febo, Irma; Innis, Bruce L; Thomas, Stephen J; Schmidt, Alexander C

2018-05-01

The safety and immunogenicity of four adjuvanted formulations of an investigational tetravalent dengue purified inactivated vaccine (DPIV) were evaluated in a predominantly dengue-primed population in Puerto Rico. In this placebo-controlled, randomized, observer-blind, phase I trial, 100 healthy adults were randomized 1:1:1:1:1 to receive DPIV at Day (D)0 and D28 (1 μg per dengue virus [DENV] type 1-4 adjuvanted with either alum, AS01 E or AS03 B , or 4 μg per DENV type adjuvanted with alum) or saline placebo. Functional antibody responses were assessed using a microneutralization assay at D56, Month (M)7, and M13. All DPIV formulations were well tolerated and no safety signals were identified through M13. The M13 according-to-protocol (ATP) immunogenicity cohort included 83 participants. The ATP analysis of immunogenicity was performed only on the 78 subjects seropositive for ≥ 1 DENV type at baseline: 69 tetravalent, three trivalent, two bivalent, and four monovalent. In all DPIV groups, geometric mean antibody titers (GMTs) increased from D0 to D56 and waned modestly through M13, while remaining well above prevaccination levels. The 4 μg + alum and the AS01 E - and AS03 B -adjuvanted formulations were highly immunogenic, with M13-neutralizing antibody GMTs against all four DENV types above 1,000. M13/D0 GMT ratios were highest in the 1 μg + AS03 B group (ranging 3.2-3.7 depending on the DENV type). These results encourage continued clinical development of DPIV (ClinicalTrials.gov: NCT01702857).

Fimbrial phase variation

DEFF Research Database (Denmark)

Khandige, Surabhi; Møller-Jensen, Jakob

2016-01-01

Surface fimbriae of pathogenic Escherichia coli facilitate sensing, adhesion and even invasion of host epithelial cells. While it is known that the pathogen has the potential to express a plethora of fimbrial variants susceptible to rapid phase ON/OFF variation, it is an open question if the fimb......Surface fimbriae of pathogenic Escherichia coli facilitate sensing, adhesion and even invasion of host epithelial cells. While it is known that the pathogen has the potential to express a plethora of fimbrial variants susceptible to rapid phase ON/OFF variation, it is an open question...... if the fimbrial diversity seen at the population level is the product of random stochasticity or a concerted effort based on active communication. Here we discuss the possibility of a mechanism alternative to a stochastic fimbrial phase variation model affecting the dynamics of a heterogeneous population....

Computational wavelength resolution for in-line lensless holography: phase-coded diffraction patterns and wavefront group-sparsity

Science.gov (United States)

Katkovnik, Vladimir; Shevkunov, Igor; Petrov, Nikolay V.; Egiazarian, Karen

2017-06-01

In-line lensless holography is considered with a random phase modulation at the object plane. The forward wavefront propagation is modelled using the Fourier transform with the angular spectrum transfer function. The multiple intensities (holograms) recorded by the sensor are random due to the random phase modulation and noisy with Poissonian noise distribution. It is shown by computational experiments that high-accuracy reconstructions can be achieved with resolution going up to the two thirds of the wavelength. With respect to the sensor pixel size it is a super-resolution with a factor of 32. The algorithm designed for optimal superresolution phase/amplitude reconstruction from Poissonian data is based on the general methodology developed for phase retrieval with a pixel-wise resolution in V. Katkovnik, "Phase retrieval from noisy data based on sparse approximation of object phase and amplitude", http://www.cs.tut.fi/ lasip/DDT/index3.html.

Boson-triboson Scattering with Yamaguchi potential. 2. Inclusion of additional p-wave component for the 3+1-subamplitude

International Nuclear Information System (INIS)

Matsui, Yoshiko

1999-01-01

In order to investigate the p-wave contribution from the 3+1-subamplitude in the S-wave phase shift for boson-triboson elastic scattering when the Yamaguchi potential for the two-body interaction is assumed, the Faddeev-Osborn equation for a system of four identical bosons in solved numerically by extending the previous calculation to include the p-wave component for the 3+1-subamplitude. The results obtained closely resemble the previous results. The calculated phase shift generally has the standard behavior of the two-body phase shift for a loosely bound state and has further characteristic behavior represented by a valley witha peak as fine structure. The phase shift obtained in the present calculation has a higher peak and a deeper valley than the previous one, while the positions of the peak and the valley in the two sets of results agree precisely. Thus the calculated resonance energies are the same as those obtained in the previous result. (author)

The SafeBoosC II randomized trial

DEFF Research Database (Denmark)

Plomgaard, Anne M; van Oeveren, Wim; Petersen, Tue Hvass

2016-01-01

BACKGROUND: The SafeBoosC phase II multicentre randomized clinical trial investigated the benefits and harms of monitoring cerebral oxygenation by near-infrared spectroscopy (NIRS) combined with an evidence-based treatment guideline vs. no NIRS data and treatment as usual in the control group...

Phase development and kinetics of high temperature Bi-2223 phase

International Nuclear Information System (INIS)

Yavuz, M.; Maeda, H.; Hua, K.L.; Shi, X.D.

1998-01-01

The two-dimensional nucleation (random)-growth mechanism were observed as a support for the related previous works, which is attributable to the growth of the Bi-2223 grain in the a-b plane direction of the Bi-2212 matrix is being much faster than in the c-direction, or that the early-formed plate-like 2212 phase confines the 2223 product. At the beginning of the reaction, the additional phases are partially melted. Because of the structure, composition and thermal fluctuation, the 2223 nucleates and grows in the phase boundary between the liquid phase and Bi-2212. It was shown here that the nucleation and the growth rate were relatively fast between 0 and 36 h. At the final stage, between 36 and 60 h, because of the impingement of the growth fronts of different nuclei, the high formation rate of 2223 is suppressed. The major reactant 2212 remains as a solid and its plate-like configuration determines the two dimensional nature of the reaction. The amount of liquid forms during reaction is small. (orig.)

B-splines and Faddeev equations

International Nuclear Information System (INIS)

Huizing, A.J.

1990-01-01

Two numerical methods for solving the three-body equations describing relativistic pion deuteron scattering have been investigated. For separable two body interactions these equations form a set of coupled one-dimensional integral equations. They are plagued by singularities which occur in the kernel of the integral equations as well as in the solution. The methods to solve these equations differ in the way they treat the singularities. First the Fuda-Stuivenberg method is discussed. The basic idea of this method is an one time iteration of the set of integral equations to treat the logarithmic singularities. In the second method, the spline method, the unknown solution is approximated by splines. Cubic splines have been used with cubic B-splines as basis. If the solution is approximated by a linear combination of basis functions, an integral equation can be transformed into a set of linear equations for the expansion coefficients. This set of linear equations is solved by standard means. Splines are determined by points called knots. A proper choice of splines to approach the solution stands for a proper choice of the knots. The solution of the three-body scattering equations has a square root behaviour at a certain point. Hence it was investigated how the knots should be chosen to approximate the square root function by cubic B-splines in an optimal way. Before applying this method to solve numerically the three-body equations describing pion-deuteron scattering, an analytically solvable example has been constructed with a singularity structure of both kernel and solution comparable to those of the three-body equations. The accuracy of the numerical solution was determined to a large extent by the accuracy of the approximation of the square root part. The results for a pion laboratory energy of 47.4 MeV agree very well with those from literature. In a complete calculation for 47.7 MeV the spline method turned out to be a factor thousand faster than the Fuda-Stuivenberg method. (H.W.). 120 refs.; 14 figs.; 17 tabs

Phase 2 Randomized, Dose-Ranging Study of Oxymetazoline Cream for Treatment of Persistent Facial Erythema Associated With Rosacea.

Science.gov (United States)

DuBois, Janet; Dover, Jeffrey S; Jones, Terry M; Weiss, Robert A; Berk, David R; Ahluwalia, Gurpreet

2018-03-01

Rosacea is a chronic dermatologic condition with limited treatment options. This phase 2 study evaluated the optimal oxymetazoline dosing regimen in patients with moderate to severe persistent facial erythema of rosacea. Patients were randomly assigned to oxymetazoline cream, 0.5%, 1.0%, or 1.5%, or vehicle, administered once daily (QD) or twice daily (BID) for 28 consecutive days. The primary efficacy endpoint was the proportion of patients with ≥2-grade improvement from baseline on the Clinician Erythema Assessment (CEA) and the Subject Self-Assessment of erythema (SSA-1) on day 28. Safety assessments included treatment-emergent adverse events and dermal tolerability. A total of 356 patients were treated (mean age, 50.0 years; 80.1% female). The proportions of patients achieving the primary endpoint were significantly higher with oxymetazoline 0.5% QD (P=0.049), 1.0% QD (P=0.006), 1.5% QD (P=0.012), 1.0% BID (P=0.021), and 1.5% BID (P=0.006) versus their respective vehicles. For both QD and BID dosing, the efficacy of oxymetazoline 1.0% was greater than the 0.5% dose and comparable to the 1.5% dose. Safety and application-site tolerability were similar across groups. Short-term treatment period. Oxymetazoline 1.0% QD provided the optimal dosing regimen and was selected for evaluation in phase 3 clinical studies. J Drugs Dermatol. 2018;17(3):308-316.

Safety and immunogenicity of an AMA1 malaria vaccine in Malian children: results of a phase 1 randomized controlled trial.

Directory of Open Access Journals (Sweden)

Mahamadou A Thera

2010-02-01

Full Text Available The objective was to evaluate the safety and immunogenicity of the AMA1-based malaria vaccine FMP2.1/AS02(A in children exposed to seasonal falciparum malaria.A Phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02(A is a recombinant protein (FMP2.1 based on apical membrane antigen 1 (AMA1 from the 3D7 clone of P. falciparum, formulated in the Adjuvant System AS02(A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert. One hundred healthy Malian children aged 1-6 years were recruited into 3 cohorts and randomized to receive either 10 microg FMP2.1 in 0.1 mL AS02(A, or 25 microg FMP2.1 in 0.25 mL AS02(A, or 50 microg FMP2.1 50 microg in 0.5 mL AS02(A, or rabies vaccine. Three doses of vaccine were given at 0, 1 and 2 months, and children were followed for 1 year. Solicited symptoms were assessed for 7 days and unsolicited symptoms for 30 days after each vaccination. Serious adverse events were assessed throughout the study. Transient local pain and swelling were common and more frequent in all malaria vaccine dosage groups than in the comparator group, but were acceptable to parents of participants. Levels of anti-AMA1 antibodies measured by ELISA increased significantly (at least 100-fold compared to baseline in all 3 malaria vaccine groups, and remained high during the year of follow up.The FMP2.1/AS02(A vaccine had a good safety profile, was well-tolerated, and induced high and sustained antibody levels in malaria-exposed children. This malaria vaccine is being evaluated in a Phase 2 efficacy trial in children at this site.ClinicalTrials.gov NCT00358332 [NCT00358332].

Safety and immunogenicity of an AMA-1 malaria vaccine in Malian adults: results of a phase 1 randomized controlled trial.

Directory of Open Access Journals (Sweden)

Mahamadou A Thera

2008-01-01

Full Text Available The objective was to evaluate the safety, reactogenicity and immunogenicity of the AMA-1-based blood-stage malaria vaccine FMP2.1/AS02A in adults exposed to seasonal malaria.A phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02A is a recombinant protein (FMP2.1 based on apical membrane antigen-1 (AMA-1 from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert. Sixty healthy, malaria-experienced adults aged 18-55 y were recruited into 2 cohorts and randomized to receive either a half dose or full dose of the malaria vaccine (FMP2.1 25 microg/AS02A 0.25 mL or FMP2.1 50 microg/AS02A 0.5 mL or rabies vaccine given in 3 doses at 0, 1 and 2 mo, and were followed for 1 y. Solicited symptoms were assessed for 7 d and unsolicited symptoms for 30 d after each vaccination. Serious adverse events were assessed throughout the study. Titers of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed on sera collected at pre- and post-vaccination time points. Transient local pain and swelling were common and more frequent in both malaria vaccine dosage groups than in the comparator group. Anti-AMA-1 antibodies increased significantly in both malaria vaccine groups, peaking at nearly 5-fold and more than 6-fold higher than baseline in the half-dose and full-dose groups, respectively.The FMP2.1/AS02A vaccine had a good safety profile, was well-tolerated, and was highly immunogenic in malaria-exposed adults. This malaria vaccine is being evaluated in Phase 1 and 2 trials in children at this site.

Application of the random phase approximation to complex problems in materials science

International Nuclear Information System (INIS)

Schimka, L.

2012-01-01

This thesis is devoted to the assessment and application of the random phase approximation (RPA) in the adiabatic-connection fluctuation-dissipation (ACFD) framework in solid state physics. The first part presents a review of density functional theory (DFT) and the ACFD theorem in the RPA. This includes an introduction to the many-body problem as well as a description of the implementation of the RPA in the Vienna Ab-initio Simulation Package (VASP). In the results part, the quality of the RPA is assessed and its performance compared to three (beyond) DFT functionals. The experimental values are corrected for the effect of phonon zero-point vibrational energies which were calculated at the DFT level from ab-initio. We find that the RPA describes all bonding situations very accurately, making it a promising candidate for more complex problems in solid state physics. In light of these findings, we investigate the carbon-water interaction in two specific cases: the adsorption of water on benzene and the adsorption of water on a graphene layer. We compare our results to a different correlated method: diffusion Monte Carlo (DMC). We find very good agreement and thus believe that our values can serve as a benchmark for the development of other DFT functionals to treat water-carbon interfaces. The highlight of this thesis is the successful application of the RPA to the long-standing and (at DFT level) unsolved CO adsorption puzzle. We show results for CO adsorption on Cu, late 4d metals and Pt. RPA is at present the only ab-initio method that describes adsorption and surface energies accurately at the same time and predicts the correct adsorption site in every single case. (author) [de

Gribov ambiguity in asymptotically AdS three-dimensional gravity

International Nuclear Information System (INIS)

Anabalon, Andres; Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio

2011-01-01

In this paper the zero modes of the de Donder gauge Faddeev-Popov operator for three-dimensional gravity with negative cosmological constant are analyzed. It is found that the AdS 3 vacuum produces (infinitely many) normalizable smooth zero modes of the Faddeev-Popov operator. On the other hand, it is found that the Banados-Teitelboim-Zanelli black hole (including the zero mass black hole) does not generate zero modes. This differs from the usual Gribov problem in QCD where, close to the maximally symmetric vacuum, the Faddeev-Popov determinant is positive definite while 'far enough' from the vacuum it can vanish. This suggests that the zero mass Banados-Teitelboim-Zanelli black hole could be a suitable ground state of three-dimensional gravity with negative cosmological constant. Because of the kinematic origin of this result, it also applies for other covariant gravity theories in three dimensions with AdS 3 as maximally symmetric solution, such as new massive gravity and topologically massive gravity. The relevance of these results for supersymmetry breaking is pointed out.

Assessing the performance of the random phase approximation for exchange and superexchange coupling constants in magnetic crystalline solids

DEFF Research Database (Denmark)

Olsen, Thomas

2017-01-01

The random phase approximation (RPA) for total energies has previously been shown to provide a qualitatively correct description of static correlation in molecular systems, where density functional theory (DFT) with local functionals are bound to fail. This immediately poses the question of whether...... the RPA is also able to capture the correct physics of strongly correlated solids such asMott insulators. Due to strong electron localization, magnetic interactions in such systems are dominated by superexchange, which in the simplest picture can be regarded as the analog of static correlation...... for molecules. In this paper, we investigate the performance of the RPA for evaluating both superexchange and direct exchange interactions in the magnetic solids NiO, MnO, Na3Cu2SbO6, Sr2CuO3, Sr2CuTeO6, and a monolayer of CrI3, which were chosen to represent a broad variety of magnetic interactions...

Plasmon response in K, Na and Li clusters: systematics using the separable random-phase approximation with pseudo-Hamiltonians

International Nuclear Information System (INIS)

Kleinig, W.; Nesterenko, V.O.; Reinhard, P.-G.; Serra, Ll.

1998-01-01

The systematics of the plasmon response in spherical K, Na and Li clusters in a wide size region (8≤N≤440) is studied. We have considered two simplifying approximations whose validity has been established previously. First, a separable approach to the random-phase approximation is used. This involves an expansion of the residual interaction into a sum of separable terms until convergence is reached. Second, the electron-ion interaction is modelled by using the pseudo-Hamiltonian jellium model (MHJM) which includes nonlocal effects by means of realistic atomic pseudo-Hamiltonians. In cases where nonlocal effects are negligible the Structure Averaged Jellium Model (SAJM) has been used. Good agreement with available experimental data is achieved for K, Na (using the SAJM) and small Li clusters (invoking the PHJM). The trends for peak position and width are generally well reproduced, even up to details of the Landau fragmentation in several clusters. Less good agreement, however, is found for large Li clusters. This remains an open question

Eigenstate Phase Transitions

Science.gov (United States)

Zhao, Bo

Phase transitions are one of the most exciting physical phenomena ever discovered. The understanding of phase transitions has long been of interest. Recently eigenstate phase transitions have been discovered and studied; they are drastically different from traditional thermal phase transitions. In eigenstate phase transitions, a sharp change is exhibited in properties of the many-body eigenstates of the Hamiltonian of a quantum system, but not the thermal equilibrium properties of the same system. In this thesis, we study two different types of eigenstate phase transitions. The first is the eigenstate phase transition within the ferromagnetic phase of an infinite-range spin model. By studying the interplay of the eigenstate thermalization hypothesis and Ising symmetry breaking, we find two eigenstate phase transitions within the ferromagnetic phase: In the lowest-temperature phase the magnetization can macroscopically oscillate by quantum tunneling between up and down. The relaxation of the magnetization is always overdamped in the remainder of the ferromagnetic phase, which is further divided into phases where the system thermally activates itself over the barrier between the up and down states, and where it quantum tunnels. The second is the many-body localization phase transition. The eigenstates on one side of the transition obey the eigenstate thermalization hypothesis; the eigenstates on the other side are many-body localized, and thus thermal equilibrium need not be achieved for an initial state even after evolving for an arbitrary long time. We study this many-body localization phase transition in the strong disorder renormalization group framework. After setting up a set of coarse-graining rules for a general one dimensional chain, we get a simple "toy model'' and obtain an almost purely analytical solution to the infinite-randomness critical fixed point renormalization group equation. We also get an estimate of the correlation length critical exponent nu

Impact of wave phase jumps on stochastic heating

International Nuclear Information System (INIS)

Zasenko, V.I.; Zagorodny, A.G.; Cherniak, O.M.

2016-01-01

Interaction of charged particles with fields of random waves brings about known effects of stochastic acceleration and heating. Jumps of wave phases can increase the intensity of these processes substantially. Numerical simulation of particle heating and acceleration by waves with regular phases, waves with jumping phase and stochastic electric field impulses is performed. Comparison of the results shows that to some extent an impact of phase jumps is similar to the action of separate field impulses. Jumps of phase not only increase the intensity of resonant particle heating but involves in this process non-resonant particles from a wide range of initial velocities

Random crystal field effects on the integer and half-integer mixed-spin system

Science.gov (United States)

Yigit, Ali; Albayrak, Erhan

2018-05-01

In this work, we have focused on the random crystal field effects on the phase diagrams of the mixed spin-1 and spin-5/2 Ising system obtained by utilizing the exact recursion relations (ERR) on the Bethe lattice (BL). The distribution function P(Di) = pδ [Di - D(1 + α) ] +(1 - p) δ [Di - D(1 - α) ] is used to randomize the crystal field.The phase diagrams are found to exhibit second- and first-order phase transitions depending on the values of α, D and p. It is also observed that the model displays tricritical point, isolated point, critical end point and three compensation temperatures for suitable values of the system parameters.

Spherically symmetric random walks. II. Dimensionally dependent critical behavior

International Nuclear Information System (INIS)

Bender, C.M.; Boettcher, S.; Meisinger, P.N.

1996-01-01

A recently developed model of random walks on a D-dimensional hyperspherical lattice, where D is not restricted to integer values, is extended to include the possibility of creating and annihilating random walkers. Steady-state distributions of random walkers are obtained for all dimensions D approx-gt 0 by solving a discrete eigenvalue problem. These distributions exhibit dimensionally dependent critical behavior as a function of the birth rate. This remarkably simple model exhibits a second-order phase transition with a universal, nontrivial critical exponent for all dimensions D approx-gt 0. copyright 1996 The American Physical Society

Serelaxin as a potential treatment for renal dysfunction in cirrhosis: Preclinical evaluation and results of a randomized phase 2 trial.

Directory of Open Access Journals (Sweden)

Victoria K Snowdon

2017-02-01

Full Text Available Chronic liver scarring from any cause leads to cirrhosis, portal hypertension, and a progressive decline in renal blood flow and renal function. Extreme renal vasoconstriction characterizes hepatorenal syndrome, a functional and potentially reversible form of acute kidney injury in patients with advanced cirrhosis, but current therapy with systemic vasoconstrictors is ineffective in a substantial proportion of patients and is limited by ischemic adverse events. Serelaxin (recombinant human relaxin-2 is a peptide molecule with anti-fibrotic and vasoprotective properties that binds to relaxin family peptide receptor-1 (RXFP1 and has been shown to increase renal perfusion in healthy human volunteers. We hypothesized that serelaxin could ameliorate renal vasoconstriction and renal dysfunction in patients with cirrhosis and portal hypertension.To establish preclinical proof of concept, we developed two independent rat models of cirrhosis that were characterized by progressive reduction in renal blood flow and glomerular filtration rate and showed evidence of renal endothelial dysfunction. We then set out to further explore and validate our hypothesis in a phase 2 randomized open-label parallel-group study in male and female patients with alcohol-related cirrhosis and portal hypertension. Forty patients were randomized 1:1 to treatment with serelaxin intravenous (i.v. infusion (for 60 min at 80 μg/kg/d and then 60 min at 30 μg/kg/d or terlipressin (single 2-mg i.v. bolus, and the regional hemodynamic effects were quantified by phase contrast magnetic resonance angiography at baseline and after 120 min. The primary endpoint was the change from baseline in total renal artery blood flow. Therapeutic targeting of renal vasoconstriction with serelaxin in the rat models increased kidney perfusion, oxygenation, and function through reduction in renal vascular resistance, reversal of endothelial dysfunction, and increased activation of the AKT

Role of random electric fields in relaxors

Science.gov (United States)

Phelan, Daniel; Stock, Christopher; Rodriguez-Rivera, Jose A.; Chi, Songxue; Leão, Juscelino; Long, Xifa; Xie, Yujuan; Bokov, Alexei A.; Ye, Zuo-Guang; Ganesh, Panchapakesan; Gehring, Peter M.

2014-01-01

PbZr1–xTixO3 (PZT) and Pb(Mg1/3Nb2/3)1–xTixO3 (PMN-xPT) are complex lead-oxide perovskites that display exceptional piezoelectric properties for pseudorhombohedral compositions near a tetragonal phase boundary. In PZT these compositions are ferroelectrics, but in PMN-xPT they are relaxors because the dielectric permittivity is frequency dependent and exhibits non-Arrhenius behavior. We show that the nanoscale structure unique to PMN-xPT and other lead-oxide perovskite relaxors is absent in PZT and correlates with a greater than 100% enhancement of the longitudinal piezoelectric coefficient in PMN-xPT relative to that in PZT. By comparing dielectric, structural, lattice dynamical, and piezoelectric measurements on PZT and PMN-xPT, two nearly identical compounds that represent weak and strong random electric field limits, we show that quenched (static) random fields establish the relaxor phase and identify the order parameter. PMID:24449912

Theory of Random Anisotropic Magnetic Alloys

DEFF Research Database (Denmark)

Lindgård, Per-Anker

1976-01-01

A mean-field-crystal-field theory is developed for random, multicomponent, anisotropic magnetic alloys. It is specially applicable to rare-earth alloys. A discussion is given of multicritical points and phase transitions between various states characterized by order parameters with different...... spatial directions or different ordering wave vectors. Theoretical predictions based on known parameters for the phase diagrams and magnetic moments for the binary rare-earth alloys of Tb, Dy, Ho, and Er, Tb-Tm, Nd-Pr, and pure double-hcp Nd agree qualitatively with the experimental observations...... fluctuation corrections in the mean-field results is also discussed....

Cooperation and Phase Separation Driven by a Coevolving Snowdrift Game

International Nuclear Information System (INIS)

Du Peng; Xu Chen; Zhang Wen

2015-01-01

We investigate the cooperative behavior and the phase separation in a coevolving system. Agents in the system constructed by a regular random network initially play the snowdrift game with their neighbors. They try to obtain a better competing environment by imitating a neighbor's more successful strategy or cutting the connection to a defective neighbor and randomly rewiring to another agent so as to seek a better neighborhood. The dynamic process of strategy imitation and relationship among agents due to rewiring neighbors may drive the system into different states. The simulation results show that there are three different phases in the q-r plane, where q is the rewiring probability and r is the cost-to-benefit ratio. One is a static phase of a pure cooperative cluster with a few isolated defectors. The other two belong to active phases with one of a main mixed-strategy cluster and the other of a pure defective state. We find that a simple mean field theory can predict correctly the static phase and the active phase of the main mixed-strategy cluster. The theoretical boundary line between the two phases is in good agreement with the simulation result. (paper)

The dressed atom as binary phase modulator: towards attojoule/edge optical phase-shift keying.

Science.gov (United States)

Kerckhoff, Joseph; Armen, Michael A; Pavlichin, Dmitri S; Mabuchi, Hideo

2011-03-28

We use a single 133Cs atom strongly coupled to an optical resonator to induce random binary phase modulation of a near infra-red, ∼ 500 pW laser beam, with each modulation edge caused by the dissipation of a single photon (≈ 0.23 aJ) by the atom. While our ability to deterministically induce phase edges with an additional optical control beam is limited thus far, theoretical analysis of an analogous, solid-state system indicates that efficient external control should be achievable in demonstrated nanophotonic systems.

Improving the luteal phase after ovarian stimulation

DEFF Research Database (Denmark)

Andersen, Claus Yding; Vilbour Andersen, K

2014-01-01

The human chorionic gonadotrophin (HCG) trigger used for final follicular maturation in connection with assisted reproduction treatment combines ovulation induction and early luteal-phase stimulation of the corpora lutea. The use of a gonadotrophin-releasing hormone agonist (GnRHa) for final...... follicular maturation has, however, for the first time allowed a separation of the ovulatory signal from the early luteal-phase support. This has generated new information that may improve the currently employed luteal-phase support. Thus, combined results from a number of randomized controlled trials using...

Safety of a silicone elastomer vaginal ring as potential microbicide delivery method in African women: A Phase 1 randomized trial.

Science.gov (United States)

Nel, Annaléne; Martins, Janine; Bekker, Linda-Gail; Ramjee, Gita; Masenga, Gileard; Rees, Helen; van Niekerk, Neliëtte

2018-01-01

Women in sub-Saharan Africa are in urgent need of female-initiated human immunodeficiency virus (HIV) preventative methods. Vaginal rings are one dosage form in development for delivery of HIV microbicides. However, African women have limited experience with vaginal rings. This Phase I, randomized, crossover trial assessed and compared the safety, acceptability and adherence of a silicone elastomer placebo vaginal ring, intended as a microbicide delivery method, inserted for a 12-week period in healthy, HIV-negative, sexually active women in South Africa and Tanzania. 170 women, aged 18 to 35 years were enrolled with 88 women randomized to Group A, using a placebo vaginal ring for 12 weeks followed by a 12-week safety observation period. 82 women were randomized to Group B and observed for safety first, followed by a placebo vaginal ring for 12 weeks. Safety was assessed by clinical laboratory assessments, pelvic/colposcopy examinations and adverse events. Possible carry-over effect was addressed by ensuring no signs or symptoms of genital irritation at crossover. No safety concerns were identified for any safety variables assessed during the trial. No serious adverse events were reported considered related to the placebo vaginal ring. Vaginal candidiasis was the most common adverse event occurring in 11% of participants during each trial period. Vaginal discharge (2%), vaginal odour (2%), and bacterial vaginitis (2%) were assessed as possibly or probably related to the vaginal ring. Thirty-four percent of participants had sexually transmitted infections (STIs) at screening, compared to 12% of participants who tested positive for STIs at crossover and the final trial visit. Three participants (2%) tested HIV positive during the trial. The silicone elastomer vaginal ring had no safety concerns, demonstrating a profile favorable for further development for topical release of antiretroviral-based microbicides.

Self-dual random-plaquette gauge model and the quantum toric code

Science.gov (United States)

Takeda, Koujin; Nishimori, Hidetoshi

2004-05-01

We study the four-dimensional Z2 random-plaquette lattice gauge theory as a model of topological quantum memory, the toric code in particular. In this model, the procedure of quantum error correction works properly in the ordered (Higgs) phase, and phase boundary between the ordered (Higgs) and disordered (confinement) phases gives the accuracy threshold of error correction. Using self-duality of the model in conjunction with the replica method, we show that this model has exactly the same mathematical structure as that of the two-dimensional random-bond Ising model, which has been studied very extensively. This observation enables us to derive a conjecture on the exact location of the multicritical point (accuracy threshold) of the model, pc=0.889972…, and leads to several nontrivial results including bounds on the accuracy threshold in three dimensions.

Self-dual random-plaquette gauge model and the quantum toric code

International Nuclear Information System (INIS)

Takeda, Koujin; Nishimori, Hidetoshi

2004-01-01

We study the four-dimensional Z 2 random-plaquette lattice gauge theory as a model of topological quantum memory, the toric code in particular. In this model, the procedure of quantum error correction works properly in the ordered (Higgs) phase, and phase boundary between the ordered (Higgs) and disordered (confinement) phases gives the accuracy threshold of error correction. Using self-duality of the model in conjunction with the replica method, we show that this model has exactly the same mathematical structure as that of the two-dimensional random-bond Ising model, which has been studied very extensively. This observation enables us to derive a conjecture on the exact location of the multicritical point (accuracy threshold) of the model, p c =0.889972..., and leads to several nontrivial results including bounds on the accuracy threshold in three dimensions

Reference Determinant Dependence of the Random Phase Approximation in 3d Transition Metal Chemistry.

Science.gov (United States)

Bates, J E; Mezei, P D; Csonka, G I; Sun, J; Ruzsinszky, A

2017-01-10

Without extensive fitting, accurate prediction of transition metal chemistry is a challenge for semilocal and hybrid density funcitonals. The Random Phase Approximation (RPA) has been shown to yield superior results to semilocal functionals for main group thermochemistry, but much less is known about its performance for transition metals. We have therefore analyzed the behavior of reaction energies, barrier heights, and ligand dissociation energies obtained with RPA and compare our results to several semilocal and hybrid functionals. Particular attention is paid to the reference determinant dependence of RPA. We find that typically the results do not vary much between semilocal or hybrid functionals as a reference, as long as the fraction of exact exchange (EXX) mixing in the hybrid functional is small. For large fractions of EXX mixing, however, the Hartree-Fock-like nature of the determinant can severely degrade the performance. Overall, RPA systematically reduces the errors of semilocal functionals and delivers excellent performance from a single reference determinant for inherently multireference reactions. The behavior of dual hybrids that combine RPA correlation with a hybrid exchange energy was also explored, but ultimately did not lead to a systematic improvement compared to traditional RPA for these systems. We rationalize this conclusion by decomposing the contributions to the reaction energies, and briefly discuss the possible implications for double-hybrid functionals based on RPA. The correlation between EXX mixing and spin-symmetry breaking is also discussed.

Density functional formulation of the random-phase approximation for inhomogeneous fluids: Application to the Gaussian core and Coulomb particles.

Science.gov (United States)

Frydel, Derek; Ma, Manman

2016-06-01

Using the adiabatic connection, we formulate the free energy in terms of the correlation function of a fictitious system, h_{λ}(r,r^{'}), in which interactions λu(r,r^{'}) are gradually switched on as λ changes from 0 to 1. The function h_{λ}(r,r^{'}) is then obtained from the inhomogeneous Ornstein-Zernike equation and the two equations constitute a general liquid-state framework for treating inhomogeneous fluids. The two equations do not yet constitute a closed set. In the present work we use the closure c_{λ}(r,r^{'})≈-λβu(r,r^{'}), known as the random-phase approximation (RPA). We demonstrate that the RPA is identical with the variational Gaussian approximation derived within the field-theoretical framework, originally derived and used for charged particles. We apply our generalized RPA approximation to the Gaussian core model and Coulomb charges.

Gemcitabine Plus Docetaxel Versus Docetaxel in Patients With Predominantly Human Epidermal Growth Factor Receptor 2-Negative Locally Advanced or Metastatic Breast Cancer: A Randomized, Phase III Study by the Danish Breast Cancer Cooperative Group

DEFF Research Database (Denmark)

Nielsen, Dorte L; Bjerre, Karsten D; Jakobsen, Erik H

2011-01-01

PURPOSE The objective of this phase III study was to compare the efficacy of gemcitabine plus docetaxel (GD) versus docetaxel in patients with advanced breast cancer. PATIENTS AND METHODS Predominantly human epidermal growth factor receptor 2 (HER2) -negative patients were randomly assigned...

Performance analysis of spectral-phase-encoded optical code-division multiple-access system regarding the incorrectly decoded signal as a nonstationary random process

Science.gov (United States)

Yan, Meng; Yao, Minyu; Zhang, Hongming

2005-11-01

The performance of a spectral-phase-encoded (SPE) optical code-division multiple-access (OCDMA) system is analyzed. Regarding the incorrectly decoded signal (IDS) as a nonstationary random process, we derive a novel probability distribution for it. The probability distribution of the IDS is considered a chi-squared distribution with degrees of freedom r=1, which is more reasonable and accurate than in previous work. The bit error rate (BER) of an SPE OCDMA system under multiple-access interference is evaluated. Numerical results show that the system can sustain very low BER even when there are multiple simultaneous users, and as the code length becomes longer or the initial pulse becomes shorter, the system performs better.

The background-quantum split symmetry in two-dimensional σ-models

International Nuclear Information System (INIS)

Blasi, A.; Delduc, F.; Sorella, S.P.

1989-01-01

A generic, non-linear, background-quantum split is translated into a BRS symmetry. The renormalization of the resulting Slavnov-Taylor identity is analyzed in the class of two-dimensional σ-models with Wess-Zumino term which suggests the adoption of a regularization independent method. We discuss the cohomology of the linearized nilpotent operator derived from the Slavnov-Taylor identity. In particular, the cohomology class with zero Faddeev-Popov charge ensures the stability of the action, while the fact that the cohomology class with one unit of Faddeev-Popov charge is empty ensures the absence of anomalies. (orig.)

Note: Fully integrated 3.2 Gbps quantum random number generator with real-time extraction

International Nuclear Information System (INIS)

Zhang, Xiao-Guang; Nie, You-Qi; Liang, Hao; Zhang, Jun; Pan, Jian-Wei; Zhou, Hongyi; Ma, Xiongfeng

2016-01-01

We present a real-time and fully integrated quantum random number generator (QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser phase fluctuations is featured for its capability of generating ultra-high-speed random numbers. However, the speed bottleneck of a practical QRNG lies on the limited speed of randomness extraction. To close the gap between the fast randomness generation and the slow post-processing, we propose a pipeline extraction algorithm based on Toeplitz matrix hashing and implement it in a high-speed field-programmable gate array. Further, all the QRNG components are integrated into a module, including a compact and actively stabilized interferometer, high-speed data acquisition, and real-time data post-processing and transmission. The final generation rate of the QRNG module with real-time extraction can reach 3.2 Gbps.

Note: Fully integrated 3.2 Gbps quantum random number generator with real-time extraction

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiao-Guang; Nie, You-Qi; Liang, Hao; Zhang, Jun, E-mail: zhangjun@ustc.edu.cn; Pan, Jian-Wei [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhou, Hongyi; Ma, Xiongfeng [Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084 (China)

2016-07-15

We present a real-time and fully integrated quantum random number generator (QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser phase fluctuations is featured for its capability of generating ultra-high-speed random numbers. However, the speed bottleneck of a practical QRNG lies on the limited speed of randomness extraction. To close the gap between the fast randomness generation and the slow post-processing, we propose a pipeline extraction algorithm based on Toeplitz matrix hashing and implement it in a high-speed field-programmable gate array. Further, all the QRNG components are integrated into a module, including a compact and actively stabilized interferometer, high-speed data acquisition, and real-time data post-processing and transmission. The final generation rate of the QRNG module with real-time extraction can reach 3.2 Gbps.

Effects of thermal and particle-number fluctuations on the giant isovector dipole modes for the 58Ni nucleus in the finite-temperature random-phase approximation

International Nuclear Information System (INIS)

Nguyen Dinhdang; Nguyen Zuythang

1988-01-01

Using the realistic single-particle energy spectrum obtained in the Woods-Saxon nucleon mean-field potential, we calculate the BCS pairing gap for 58 Ni as a function of temperature taking into account the thermal and particle-number fluctuations. The strength distributions of the electric dipole transitions and the centroids of the isovector giant dipole resonance (IV-GDR) are computed in the framework of the finite-temperature random-phase approximation (RPA) based on the Hamiltonian of the quasiparticle-phonon nuclear model with separate dipole forces. It is shown that the change of the pairing gap at finite temperature can noticeably influence the IV-GDR localisation in realistic nuclei. By taking both thermal and quasiparticle fluctuations in the pairing gap into account the effect of the phase transition from superfluid to normal in the temperature dependence of the IV-GDR centroid is completely smeared out. (author)

Self-consistent random phase approximation - application to systems of strongly correlated fermions; Approximation des phases aleatoires self-consistante - applications a des systemes de fermions fortement correles

Energy Technology Data Exchange (ETDEWEB)

Jemai, M

2004-07-01

In the present thesis we have applied the self consistent random phase approximation (SCRPA) to the Hubbard model with a small number of sites (a chain of 2, 4, 6,... sites). Earlier SCRPA had produced very good results in other models like the pairing model of Richardson. It was therefore interesting to see what kind of results the method is able to produce in the case of a more complex model like the Hubbard model. To our great satisfaction the case of two sites with two electrons (half-filling) is solved exactly by the SCRPA. This may seem a little trivial but the fact is that other respectable approximations like 'GW' or the approach with the Gutzwiller wave function yield results still far from exact. With this promising starting point, the case of 6 sites at half filling was considered next. For that case, evidently, SCRPA does not any longer give exact results. However, they are still excellent for a wide range of values of the coupling constant U, covering for instance the phase transition region towards a state with non zero magnetisation. We consider this as a good success of the theory. Non the less the case of 4 sites (a plaquette), as indeed all cases with 4n sites at half filling, turned out to have a problem because of degeneracies at the Hartree Fock level. A generalisation of the present method, including in addition to the pairs, quadruples of Fermions operators (called second RPA) is proposed to also include exactly the plaquette case in our approach. This is therefore a very interesting perspective of the present work. (author)

Randomized phase II study of a bendamustine monotherapy schedule for relapsed or refractory low-grade B-cell non-Hodgkin lymphoma or mantle cell lymphoma (RABBIT-14).

Science.gov (United States)

Itoh, Kuniaki; Igarashi, Tadahiko; Irisawa, Hiroyuki; Aotsuka, Nobuyuki; Masuda, Shinichi; Utsu, Yoshikazu; Tsujimura, Hideki; Tsukasaki, Kunihiro; Wakita, Hisashi

2017-10-30

The aim of this randomized phase II study was to improve the treatment delays and discontinuations associated with bendamustine use by comparing the effect of Benda-14 (intravenous bendamustine, 120 mg/m 2 on days 1 and 15, repeated every 4 weeks for a total of 6 cycles) with those of the standard treatment in relapsed indolent lymphoma and/or mantle cell lymphoma. Forty-six patients were randomly assigned to the treatments from September 2012 to February 2016. Treatment accomplishment rate and median relative dose intensity were similar in both arms: 38 and 63.4% in the Benda-14 arm and 41 and 66.3% in the standard treatment arm, respectively. The overall response rate and median progression-free survival, respectively, were 83% and 21.0 months for Benda-14, and 77% and 15.5 months for the standard treatment. Benda-14 induced favorable responses with less frequent hematological toxicities.

Phase transition in nonuniform Josephson arrays: Monte Carlo simulations

Science.gov (United States)

Lozovik, Yu. E.; Pomirchy, L. M.

1994-01-01

Disordered 2D system with Josephson interactions is considered. Disordered XY-model describes the granular films, Josephson arrays etc. Two types of disorder are analyzed: (1) randomly diluted system: Josephson coupling constants J ij are equal to J with probability p or zero (bond percolation problem); (2) coupling constants J ij are positive and distributed randomly and uniformly in some interval either including the vicinity of zero or apart from it. These systems are simulated by Monte Carlo method. Behaviour of potential energy, specific heat, phase correlation function and helicity modulus are analyzed. The phase diagram of the diluted system in T c-p plane is obtained.

First-order phase transition in the quantum spin glass at T=0

Energy Technology Data Exchange (ETDEWEB)

Viana, J. Roberto; Nogueira, Yamilles; Sousa, J. Ricardo de

2003-05-26

The van Hemmen model with transverse and random longitudinal field is studied to analyze the tricritical behavior in the quantum Ising spin glass at T=0. The free energy and order parameter are calculated for two types of probability distributions: Gaussian and bimodal. We obtain the phase diagram in the {omega}-H plane, where {omega} and H are the transverse and random longitudinal fields, respectively. For the case of Gaussian distribution the phase transition is of second order, while the bimodal distribution we observe second-order transition for high-transverse field and first-order transition for small transverse field, with a tricritical point in the phase diagram.

First-order phase transition in the quantum spin glass at T=0

International Nuclear Information System (INIS)

Viana, J. Roberto; Nogueira, Yamilles; Sousa, J. Ricardo de

2003-01-01

The van Hemmen model with transverse and random longitudinal field is studied to analyze the tricritical behavior in the quantum Ising spin glass at T=0. The free energy and order parameter are calculated for two types of probability distributions: Gaussian and bimodal. We obtain the phase diagram in the Ω-H plane, where Ω and H are the transverse and random longitudinal fields, respectively. For the case of Gaussian distribution the phase transition is of second order, while the bimodal distribution we observe second-order transition for high-transverse field and first-order transition for small transverse field, with a tricritical point in the phase diagram

On the Periods of the {ranshi} Random Number Generator

Science.gov (United States)

Gutbrod, F.

The stochastic properties of the pseudo-random number generator {ranshi} are discussed, with emphasis on the average period. Within a factor 2 this turns out to be the root of the maximally possible period. The actual set of periods depends on minor details of the algorithm, and the system settles down in one of only a few different cycles. These features are in perfect agreement with absolute random motion in phase space, to the extent allowed by deterministic dynamics.

Dynamics of energy storage in phase change drywall systems

Energy Technology Data Exchange (ETDEWEB)

Darkwa, K.; Kim, J.-S. [Nottingham Trent University (United Kingdom). School of the Built Environment

2005-07-01

Experimental evaluations of manufactured samples of laminated and randomly mixed phase change material (PCM) drywalls have been carried out and compared with numerical results. The analysis showed that the laminated PCM drywall performed thermally better. Even though there was a maximum 3% deviation of the average experimental result from the numerical values, the laminated PCM board achieved about 55% of the phase change process as against 48% for the randomly distributed drywall sample. The laminated board sample also released about 27% more latent heat than the randomly distributed type at the optimum time of 90 min thus validating previous simulation study. Given the experimental conditions and assumptions the experiment has proved that it is feasible to develop the laminated PCM technique for enhancing and minimising multi-dimensional heat transfers in drywall systems. Further practical developments are however encouraged to improve the overall level of heat transfer. (author)

Trunk Exercises Improve Gait Symmetry in Parkinson Disease: A Blind Phase II Randomized Controlled Trial.

Science.gov (United States)

Hubble, Ryan P; Naughton, Geraldine; Silburn, Peter A; Cole, Michael H

2018-03-01

Deficits in step-to-step symmetry and trunk muscle activations have been linked to falls in Parkinson disease. Given such symptoms are poorly managed with anti-parkinsonian medications, alternate therapies are needed. This blind phase II randomized controlled trial sought to establish whether exercise can improve step-to-step symmetry in Parkinson disease. Twenty-four Parkinson disease patients with a falls history completed baseline assessments of symptom severity, balance confidence, mobility, and quality of life. Step-to-step symmetry was assessed by deriving harmonic ratios from three-dimensional accelerations collected for the head and trunk. Patients were randomly assigned to either 12 wks of exercise and falls prevention education or falls prevention education only. Both groups repeated the baseline tests 12 and 24 wks after the initial assessment. The Australian and New Zealand Clinical Trials Registry number is ACTRN12613001175763. At 12 wks, the exercise group had statistically significant and clinically relevant improvements in anterior-posterior step-to-step trunk symmetry. In contrast, the education group recorded statistically significant and clinically meaningful reductions in medial-lateral and vertical step-to-step trunk symmetry at 12 wks. Given that step-to-step symmetry improved for the exercise group and declined for the education group after intervention, active interventions seem more suited to increasing independence and quality of life for people with Parkinson disease. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to do the following: (1) Describe the effect deficits in trunk muscle function have on gait in individuals with Parkinson disease; (2) Identify the benefits of targeted trunk exercises on step-to-step symmetry; and (3) Discuss the benefits of improving step-to-step symmetry in individuals with Parkinson

Numerical simulation of wind wave surface profiles with tuned phase spectra

Digital Repository Service at National Institute of Oceanography (India)

Varkey, M.J.

It is known that the phases of the individual harmonic components in a linear narrow band wave spectrum are uniformly random. It has been suggested by some workers that some sort of phase coupling and `locking' between the different spectral...

Simulation of phase change drywalls in a passive solar building

Energy Technology Data Exchange (ETDEWEB)

Darkwa, K.; O' Callaghan, P.W. [School of the Built Environment, The Applied Energy and Environmental Engineering Group, Nottingham Trent University, Burton Street, Nottingham NG1 4BU (United Kingdom)

2006-06-15

Integration of phase change materials (PCMs) into building fabrics is considered to be one of the potential and effective ways of minimizing energy consumption and CO{sub 2} emissions in the building sector. In order to assess the thermal effectiveness of this concept, composite PCM drywall samples (i.e. randomly-mixed and laminated PCM drywalls) have been evaluated in a model passive solar building. For a broader assessment, effects of three phase change zones (narrow, intermediate and wide) of the PCM sample were considered. The results showed that the laminated PCM sample with a narrow phase change zone was capable of increasing the minimum room temperature by about 17% more than the randomly-mixed type. Even though there was some display of non-isothermal phase change process, the laminated system proved to be thermally more effective in terms of evolution and utilization of latent heat. Further heat transfer enhancement process is however required towards the development of the laminated system. [Author].

Inertial-particle dynamics in turbulent flows: caustics, concentration fluctuations and random uncorrelated motion

International Nuclear Information System (INIS)

Gustavsson, K; Mehlig, B; Meneguz, E; Reeks, M

2012-01-01

We have performed numerical simulations of inertial particles in random model flows in the white-noise limit (at zero Kubo number, Ku = 0) and at finite Kubo numbers. Our results for the moments of relative inertial-particle velocities are in good agreement with recent theoretical results (Gustavsson and Mehlig 2011a) based on the formation of phase-space singularities in the inertial-particle dynamics (caustics). We discuss the relation between three recent approaches describing the dynamics and spatial distribution of inertial particles suspended in turbulent flows: caustic formation, real-space singularities of the deformation tensor and random uncorrelated motion. We discuss how the phase- and real-space singularities are related. Their formation is well understood in terms of a local theory. We summarise the implications for random uncorrelated motion. (paper)

Randomized phase II study of vandetanib alone or with paclitaxel and carboplatin as first-line treatment for advanced non-small-cell lung cancer.

Science.gov (United States)

Heymach, John V; Paz-Ares, Luis; De Braud, Filippo; Sebastian, Martin; Stewart, David J; Eberhardt, Wilfried E E; Ranade, Anantbhushan A; Cohen, Graham; Trigo, Jose Manuel; Sandler, Alan B; Bonomi, Philip D; Herbst, Roy S; Krebs, Annetta D; Vasselli, James; Johnson, Bruce E

2008-11-20

Vandetanib is a once-daily, oral inhibitor of vascular endothelial growth factor receptor and epidermal growth factor receptor signaling. The antitumor activity of vandetanib monotherapy or vandetanib with paclitaxel and carboplatin (VPC) was compared with paclitaxel and carboplatin (PC) in previously untreated patients with non-small-cell lung cancer (NSCLC). All NSCLC histologies and previously treated CNS metastases were permitted in this partially blinded, placebo-controlled, randomized phase II study. Patients were randomly assigned 2:1:1 to receive vandetanib, VPC, or PC. Progression-free survival (PFS) was the primary end point, and the study was powered to detect a reduced risk of progression with VPC versus PC (hazard ratio = 0.70; one-sided P 1.33 v PC). Overall survival was not significantly different between patients receiving VPC or PC. Rash, diarrhea, and hypertension were common adverse events; no pulmonary or CNS hemorrhage events required intervention. VPC could be safely administered to patients with NSCLC, including those with squamous cell histology and treated brain metastases. Compared with the PC control arm, patients receiving VPC had longer PFS, meeting the prespecified study end point, whereas those receiving vandetanib monotherapy had shorter PFS.

Perturbation analysis of complete synchronization in networks of phase oscillators.

Science.gov (United States)

Tönjes, Ralf; Blasius, Bernd

2009-08-01

The behavior of weakly coupled self-sustained oscillators can often be well described by phase equations. Here we use the paradigm of Kuramoto phase oscillators which are coupled in a network to calculate first- and second-order corrections to the frequency of the fully synchronized state for nonidentical oscillators. The topology of the underlying coupling network is reflected in the eigenvalues and eigenvectors of the network Laplacian which influence the synchronization frequency in a particular way. They characterize the importance of nodes in a network and the relations between them. Expected values for the synchronization frequency are obtained for oscillators with quenched random frequencies on a class of scale-free random networks and for a Erdös-Rényi random network. We briefly discuss an application of the perturbation theory in the second order to network structural analysis.

Singular-value demodulation of phase-shifted holograms.

Science.gov (United States)

Lopes, Fernando; Atlan, Michael

2015-06-01

We report on phase-shifted holographic interferogram demodulation by singular-value decomposition. Numerical processing of optically acquired interferograms over several modulation periods was performed in two steps: (1) rendering of off-axis complex-valued holograms by Fresnel transformation of the interferograms; and (2) eigenvalue spectrum assessment of the lag-covariance matrix of hologram pixels. Experimental results in low-light recording conditions were compared with demodulation by Fourier analysis, in the presence of random phase drifts.

Random crystal field effect on the magnetic and hysteresis behaviors of a spin-1 cylindrical nanowire

Energy Technology Data Exchange (ETDEWEB)

Zaim, N.; Zaim, A., E-mail: ah_zaim@yahoo.fr; Kerouad, M., E-mail: kerouad@fs-umi.ac.ma

2017-02-15

In this work, the magnetic behavior of the cylindrical nanowire, consisting of a ferromagnetic core of spin-1 atoms surrounded by a ferromagnetic shell of spin-1 atoms is studied in the presence of a random crystal field interaction. Based on Metropolis algorithm, the Monte Carlo simulation has been used to investigate the effects of the concentration of the random crystal field p, the crystal field D and the shell exchange interaction J{sub s} on the phase diagrams and the hysteresis behavior of the system. Some characteristic behaviors have been found, such as the first and second-order phase transitions joined by tricritical point for appropriate values of the system parameters, triple and isolated critical points can be also found. Depending on the Hamiltonian parameters, single, double and para hysteresis regions are explicitly determined. - Highlights: • Phase diagrams of a ferromagnetic nanowire are examined by the Monte Carlo simulation. • Different types of the phase diagrams are obtained. • The effect of the random crystal field on the hysteresis loops is studied. • Single, double and para hysteresis regions are explicitly determined.

Phase structure of the O(n) model on a random lattice for n > 2

DEFF Research Database (Denmark)

Durhuus, B.; Kristjansen, C.

1997-01-01

We show that coarse graining arguments invented for the analysis of multi-spin systems on a randomly triangulated surface apply also to the O(n) model on a random lattice. These arguments imply that if the model has a critical point with diverging string susceptibility, then either γ = +1....../2 or there exists a dual critical point with negative string susceptibility exponent, γ̃, related to γ by γ = γ̃/γ̃-1. Exploiting the exact solution of the O(n) model on a random lattice we show that both situations are realized for n > 2 and that the possible dual pairs of string susceptibility exponents are given...... by (γ̃, γ) = (-1/m, 1/m+1), m = 2, 3, . . . We also show that at the critical points with positive string susceptibility exponent the average number of loops on the surface diverges while the average length of a single loop stays finite....

8 Gy single-dose radiotherapy is effective in metastatic spinal cord compression: Results of a phase III randomized multicentre Italian trial

International Nuclear Information System (INIS)

Maranzano, Ernesto; Trippa, Fabio; Casale, Michelina; Costantini, Sara; Lupattelli, Marco; Bellavita, Rita; Marafioti, Luigi; Pergolizzi, Stefano; Santacaterina, Anna; Mignogna, Marcello; Silvano, Giovanni; Fusco, Vincenzo

2009-01-01

Background and purpose: In a previous randomized trial we showed that the short-course radiotherapy (RT) regimen of 8 Gy x 2 was feasible in patients with metastatic spinal cord compression (MSCC) and short life expectancy. This phase III trial was planned to determine whether in the same category of patients 8 Gy single-dose is as effective as 8 Gy x 2. Materials and methods: Three hundred and twenty-seven patients with MSCC and short life expectancy were randomly assigned to a short-course of 8 Gy x 2 or to 8 Gy single-dose RT. Median follow-up was 31 months (range, 4-58). Results: A total of 303 (93%) patients are assessable, 150 treated with the short-course and 153 with the single-dose RT. No difference in response was found between the two RT schedules adopted. Median duration of response was 5 and 4.5 months for short-course and single-dose RT (p = 0.4), respectively. The median overall survival was 4 months for all cases. Light acute toxicity was registered in a minority of cases. Late toxicity was never recorded. Conclusions: Both RT schedules adopted were effective. As already shown in several trials evaluating RT regimens in uncomplicated painful bone metastases, also MSCC patients may achieve palliation with minimal toxicity and inconvenience with a single-dose of 8 Gy.

Quantum chaos and chiral symmetry at the QCD and QED phase transition

International Nuclear Information System (INIS)

Bittner, Elmar; Markum, Harald; Pullirsch, Rainer

2001-01-01

We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) gauge theory and in full QCD as well as in quenched U(1) theory. As a measure of the fluctuation properties of the eigenvalues, we consider the nearest-neighbor spacing distribution. We find that in all regions of their phase diagrams, compact lattice gauge theories have bulk spectral correlations given by random matrix theory, which is an indication for quantum chaos. In the confinement phase, the low-lying Dirac spectrum of these quantum field theories is well described by random matrix theory, exhibiting universal behavior. Related results for gauge theories with minimal coupling are now discussed also in the chirally symmetric phase

Does the central limit theorem always apply to phase noise? Some implications for radar problems

Science.gov (United States)

Gray, John E.; Addison, Stephen R.

2017-05-01

The phase noise problem or Rayleigh problem occurs in all aspects of radar. It is an effect that a radar engineer or physicist always has to take into account as part of a design or in attempt to characterize the physics of a problem such as reverberation. Normally, the mathematical difficulties of phase noise characterization are avoided by assuming the phase noise probability distribution function (PDF) is uniformly distributed, and the Central Limit Theorem (CLT) is invoked to argue that the superposition of relatively few random components obey the CLT and hence the superposition can be treated as a normal distribution. By formalizing the characterization of phase noise (see Gray and Alouani) for an individual random variable, the summation of identically distributed random variables is the product of multiple characteristic functions (CF). The product of the CFs for phase noise has a CF that can be analyzed to understand the limitations CLT when applied to phase noise. We mirror Kolmogorov's original proof as discussed in Papoulis to show the CLT can break down for receivers that gather limited amounts of data as well as the circumstances under which it can fail for certain phase noise distributions. We then discuss the consequences of this for matched filter design as well the implications for some physics problems.

Subcritical Multiplicative Chaos for Regularized Counting Statistics from Random Matrix Theory

Science.gov (United States)

Lambert, Gaultier; Ostrovsky, Dmitry; Simm, Nick

2018-05-01

For an {N × N} Haar distributed random unitary matrix U N , we consider the random field defined by counting the number of eigenvalues of U N in a mesoscopic arc centered at the point u on the unit circle. We prove that after regularizing at a small scale {ɛN > 0}, the renormalized exponential of this field converges as N \\to ∞ to a Gaussian multiplicative chaos measure in the whole subcritical phase. We discuss implications of this result for obtaining a lower bound on the maximum of the field. We also show that the moments of the total mass converge to a Selberg-like integral and by taking a further limit as the size of the arc diverges, we establish part of the conjectures in Ostrovsky (Nonlinearity 29(2):426-464, 2016). By an analogous construction, we prove that the multiplicative chaos measure coming from the sine process has the same distribution, which strongly suggests that this limiting object should be universal. Our approach to the L 1-phase is based on a generalization of the construction in Berestycki (Electron Commun Probab 22(27):12, 2017) to random fields which are only asymptotically Gaussian. In particular, our method could have applications to other random fields coming from either random matrix theory or a different context.

DNA-based random number generation in security circuitry.

Science.gov (United States)

Gearheart, Christy M; Arazi, Benjamin; Rouchka, Eric C

2010-06-01

DNA-based circuit design is an area of research in which traditional silicon-based technologies are replaced by naturally occurring phenomena taken from biochemistry and molecular biology. This research focuses on further developing DNA-based methodologies to mimic digital data manipulation. While exhibiting fundamental principles, this work was done in conjunction with the vision that DNA-based circuitry, when the technology matures, will form the basis for a tamper-proof security module, revolutionizing the meaning and concept of tamper-proofing and possibly preventing it altogether based on accurate scientific observations. A paramount part of such a solution would be self-generation of random numbers. A novel prototype schema employs solid phase synthesis of oligonucleotides for random construction of DNA sequences; temporary storage and retrieval is achieved through plasmid vectors. A discussion of how to evaluate sequence randomness is included, as well as how these techniques are applied to a simulation of the random number generation circuitry. Simulation results show generated sequences successfully pass three selected NIST random number generation tests specified for security applications.

An X-ray CCD signal generator with true random arrival time

International Nuclear Information System (INIS)

Huo Jia; Xu Yuming; Chen Yong; Cui Weiwei; Li Wei; Zhang Ziliang; Han Dawei; Wang Yusan; Wang Juan

2011-01-01

An FPGA-based true random signal generator with adjustable amplitude and exponential distribution of time interval is presented. Since traditional true random number generators (TRNG) are resource costly and difficult to transplant, we employed a method of random number generation based on jitter and phase noise in ring oscillators formed by gates in an FPGA. In order to improve the random characteristics, a combination of two different pseudo-random processing circuits is used for post processing. The effects of the design parameters, such as sample frequency are discussed. Statistical tests indicate that the generator can well simulate the timing behavior of random signals with Poisson distribution. The X-ray CCD signal generator will be used in debugging the CCD readout system of the Low Energy X-ray Instrument onboard the Hard X-ray Modulation Telescope (HXMT). (authors)

Nonadiabatic Berry phase in nanocrystalline magnets

Directory of Open Access Journals (Sweden)

R. Skomski

2017-05-01

Full Text Available It is investigated how a Berry phase is created in polycrystalline nanomagnets and how the phase translates into an emergent magnetic field and into a topological Hall-effect contribution. The analysis starts directly from the spin of the conduction electrons and does not involve any adiabatic Hamiltonian. Completely random spin alignment in the nanocrystallites does not lead to a nonzero emergent field, but a modulation of the local magnetization does. As an explicit example, we consider a wire with a modulated cone angle.

Exploring topological phases with quantum walks

International Nuclear Information System (INIS)

Kitagawa, Takuya; Rudner, Mark S.; Berg, Erez; Demler, Eugene

2010-01-01

The quantum walk was originally proposed as a quantum-mechanical analog of the classical random walk, and has since become a powerful tool in quantum information science. In this paper, we show that discrete-time quantum walks provide a versatile platform for studying topological phases, which are currently the subject of intense theoretical and experimental investigations. In particular, we demonstrate that recent experimental realizations of quantum walks with cold atoms, photons, and ions simulate a nontrivial one-dimensional topological phase. With simple modifications, the quantum walk can be engineered to realize all of the topological phases, which have been classified in one and two dimensions. We further discuss the existence of robust edge modes at phase boundaries, which provide experimental signatures for the nontrivial topological character of the system.

Brain Tumor Segmentation Based on Random Forest

Directory of Open Access Journals (Sweden)

László Lefkovits

2016-09-01

Full Text Available In this article we present a discriminative model for tumor detection from multimodal MR images. The main part of the model is built around the random forest (RF classifier. We created an optimization algorithm able to select the important features for reducing the dimensionality of data. This method is also used to find out the training parameters used in the learning phase. The algorithm is based on random feature properties for evaluating the importance of the variable, the evolution of learning errors and the proximities between instances. The detection performances obtained have been compared with the most recent systems, offering similar results.

Ferrimagnetic Properties of Bond Dilution Mixed Blume-Capel Model with Random Single-Ion Anisotropy

International Nuclear Information System (INIS)

Liu Lei; Yan Shilei

2005-01-01

We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel model (BCM) with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points. Normal magnetic ordering states take on new phase diagrams with increasing randomness (bond and anisotropy), while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random single-ion anisotropy. Some results have not been revealed in previous papers and predicted by Neel theory of ferrimagnetism.

Phase 1b randomized trial and follow-up study in Uganda of the blood-stage malaria vaccine candidate BK-SE36.

Science.gov (United States)

Palacpac, Nirianne Marie Q; Ntege, Edward; Yeka, Adoke; Balikagala, Betty; Suzuki, Nahoko; Shirai, Hiroki; Yagi, Masanori; Ito, Kazuya; Fukushima, Wakaba; Hirota, Yoshio; Nsereko, Christopher; Okada, Takuya; Kanoi, Bernard N; Tetsutani, Kohhei; Arisue, Nobuko; Itagaki, Sawako; Tougan, Takahiro; Ishii, Ken J; Ueda, Shigeharu; Egwang, Thomas G; Horii, Toshihiro

2013-01-01

Up to now a malaria vaccine remains elusive. The Plasmodium falciparum serine repeat antigen-5 formulated with aluminum hydroxyl gel (BK-SE36) is a blood-stage malaria vaccine candidate that has undergone phase 1a trial in malaria-naive Japanese adults. We have now assessed the safety and immunogenicity of BK-SE36 in a malaria endemic area in Northern Uganda. We performed a two-stage, randomized, single-blinded, placebo-controlled phase 1b trial (Current Controlled trials ISRCTN71619711). A computer-generated sequence randomized healthy subjects for 2 subcutaneous injections at 21-day intervals in Stage1 (21-40 year-olds) to 1-mL BK-SE36 (BKSE1.0) (n = 36) or saline (n = 20) and in Stage2 (6-20 year-olds) to BKSE1.0 (n = 33), 0.5-mL BK-SE36 (BKSE0.5) (n = 33), or saline (n = 18). Subjects and laboratory personnel were blinded. Safety and antibody responses 21-days post-second vaccination (Day42) were assessed. Post-trial, to compare the risk of malaria episodes 130-365 days post-second vaccination, Stage2 subjects were age-matched to 50 control individuals. Nearly all subjects who received BK-SE36 had induration (Stage1, n = 33, 92%; Stage2, n = 63, 96%) as a local adverse event. No serious adverse event related to BK-SE36 was reported. Pre-existing anti-SE36 antibody titers negatively correlated with vaccination-induced antibody response. At Day42, change in antibody titers was significant for seronegative adults (1.95-fold higher than baseline [95% CI, 1.56-2.43], p = 0.004) and 6-10 year-olds (5.71-fold [95% CI, 2.38-13.72], p = 0.002) vaccinated with BKSE1.0. Immunogenicity response to BKSE0.5 was low and not significant (1.55-fold [95% CI, 1.24-1.94], p = 0.75). In the ancillary analysis, cumulative incidence of first malaria episodes with ≥5000 parasites/µL was 7 cases/33 subjects in BKSE1.0 and 10 cases/33 subjects in BKSE0.5 vs. 29 cases/66 subjects in the control group. Risk ratio for BKSE1.0 was 0.48 (95% CI, 0

A variational Integro-Differential Equation for three identical particles in an S-state

International Nuclear Information System (INIS)

Fabre de la Ripelle, M.; Braun, M.; Sofianos, S.A.

1997-01-01

Starting from the Schroedinger equation, a new Variational Integro-Differential Equation (VIDE) for three bosons in S-state is derived. The wave function has the simple structure of a sum of two-body amplitudes. It is shown that the new equation gives results which are three orders of magnitude better than the corresponding results obtained from a single Faddeev equation, where the pairs are in an S-state. The latter equation generates an exact solution only for S-state projected potentials. Moreover, the ghost contributions occurring in the Faddeev amplitudes for three bosons in an S-state do not exist in the new equation. (author)

Non-Abelian color dielectric - towards the effective model of the low energy QCD

International Nuclear Information System (INIS)

Wereszczynski, A.; Slusarczyk, M.

2005-01-01

Lattice motivated triplet color scalar field theory is analyzed. We consider non-minimal as well as covariant derivative coupling with SU(2) gauge fields. Field configurations generated by external electric sources are presented. Moreover non-Abelian magnetic monopoles are found. Dependence on the spatial coordinates in the obtained solutions is identical as in the usual Abelian case. We show also that after a decomposition of the fields a modified Faddeev-Niemi action can be obtained. It contains explicit O(3) symmetry breaking term parameterized by the condensate of an isoscalar field. Due to that Goldstone bosons observed in the original Faddeev-Niemi model are removed. (orig.)

Practical scheme for low energy π-d scattering

International Nuclear Information System (INIS)

Avishai, Y.; Giraud, N.; Fayard, C.; Lamot, G.H.

1978-01-01

Recently, it became clear that the solution of the π-d scattering problem in the presence of pion absorption rests outside the Faddeev theory. The most one can expect from this theory is the N-N' model Afnan-Thomas, in which the Pauli principle is violated. In the present work, we impose the exclusion principle on the Afnan-Thomas model as an ad-hoc assumption, and get a modified set of equations in which the two nucleons are indentical through all intermediate states, and non-Faddeev terms with two successive pion emissions are included (but states of more than one pion are eliminated). (orig.) [de

Pharmacokinetics and Safety of Amenamevir in Healthy Subjects: Analysis of Four Randomized Phase 1 Studies.

Science.gov (United States)

Kusawake, Tomohiro; Keirns, James J; Kowalski, Donna; den Adel, Martin; Groenendaal-van de Meent, Dorien; Takada, Akitsugu; Ohtsu, Yoshiaki; Katashima, Masataka

2017-12-01

Amenamevir (ASP2151) is a nonnucleoside antiherpesvirus compound available for the treatment of varicella-zoster virus infections. In this article we summarize the findings of four phase 1 studies in healthy participants. Four randomized phase 1 studies investigated the safety and pharmacokinetics of single and multiple doses of amenamevir, including the assessment of age group effect (nonelderly vs elderly), food effect, and the relative bioavailability of two formulations. Amenamevir was administered orally at various doses as a single dose (5-2400 mg) or daily (300 or 600 mg/day) for 7 days. Following single and multiple oral doses, amenamevir demonstrated a less than dose proportional increase in the pharmacokinetic parameters area under the plasma drug concentration versus time curve from time zero to infinity (AUC inf ) and C max . After single and multiple oral 300-mg doses of amenamevir, no apparent differences in pharmacokinetics were observed between nonelderly and elderly participants. In contrast, with the amenamevir 600-mg dose both the area under the plasma drug concentration versus time curve from time zero to 24 h and C max were slightly increased and renal clearance was decreased in elderly participants. The pharmacokinetics of amenamevir was affected by food, with AUC inf increased by about 90%. In the bioavailability study, AUC inf and C max were slightly lower following tablet versus capsule administration (decreased by 14 and 12%, respectively), with relative bioavailability of 86%. The different amenamevir doses and formulations were safe and well tolerated; no deaths or serious adverse events were reported. Amenamevir had less than dose proportional pharmacokinetic characteristics. Age may have an influence on amenamevir pharmacokinetics; however, the effect was considered minimal. The pharmacokinetics of amenamevir were affected by food, with AUC inf almost doubling when amenamevir was administered with food. The concentration versus

Ab initio lattice stability of fcc and hcp Fe-Mn random alloys

International Nuclear Information System (INIS)

Gebhardt, T; Music, D; Hallstedt, B; Schneider, J M; Ekholm, M; Abrikosov, I A; Vitos, L

2010-01-01

We have studied the lattice stability of face centred cubic (fcc) versus hexagonal close packed (hcp) Fe-Mn random alloys using ab initio calculations. In the calculations we considered the antiferromagnetic order of local moments, which for fcc alloys models the magnetic configuration of this phase at room temperature (below its Neel temperature) as well as their complete disorder, corresponding to paramagnetic fcc and hcp alloys. For both cases, the results are consistent with our thermodynamic calculations, obtained within the Calphad approach. For the room temperature magnetic configuration, the cross-over of the total energies of the hcp phase and the fcc phase of Fe-Mn alloys is at the expected Mn content, whereas for the magnetic configuration above the fcc Neel temperature, the hcp lattice is more stable within the whole composition range studied. The increase of the total energy difference between hcp and antiferromagnetic fcc due to additions of Mn as well as the stabilizing effect of antiferromagnetic ordering on the fcc phase are well displayed. These results are of relevance for understanding the deformation mechanisms of these random alloys.

Ab initio lattice stability of fcc and hcp Fe-Mn random alloys

Energy Technology Data Exchange (ETDEWEB)

Gebhardt, T; Music, D; Hallstedt, B; Schneider, J M [Materials Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Ekholm, M; Abrikosov, I A [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden); Vitos, L, E-mail: gebhardt@mch.rwth-aachen.d [Department of Materials Science and Engineering, Applied Materials Physics, oyal Institute of Technology, SE-10044 Stockholm (Sweden)

2010-07-28

We have studied the lattice stability of face centred cubic (fcc) versus hexagonal close packed (hcp) Fe-Mn random alloys using ab initio calculations. In the calculations we considered the antiferromagnetic order of local moments, which for fcc alloys models the magnetic configuration of this phase at room temperature (below its Neel temperature) as well as their complete disorder, corresponding to paramagnetic fcc and hcp alloys. For both cases, the results are consistent with our thermodynamic calculations, obtained within the Calphad approach. For the room temperature magnetic configuration, the cross-over of the total energies of the hcp phase and the fcc phase of Fe-Mn alloys is at the expected Mn content, whereas for the magnetic configuration above the fcc Neel temperature, the hcp lattice is more stable within the whole composition range studied. The increase of the total energy difference between hcp and antiferromagnetic fcc due to additions of Mn as well as the stabilizing effect of antiferromagnetic ordering on the fcc phase are well displayed. These results are of relevance for understanding the deformation mechanisms of these random alloys.

Neoadjuvant chemoradiation therapy with gemcitabine/cisplatin and surgery versus immediate surgery in resectable pancreatic cancer. Results of the first prospective randomized phase II trial

International Nuclear Information System (INIS)

Golcher, Henriette; Merkel, Susanne; Hohenberger, Werner; Brunner, Thomas B.; Witzigmann, Helmut; Marti, Lukas; Bechstein, Wolf-Otto; Bruns, Christiane; Jungnickel, Henry; Schreiber, Stefan; Grabenbauer, Gerhard G.; Meyer, Thomas; Fietkau, Rainer

2015-01-01

In nonrandomized trials, neoadjuvant treatment was reported to prolong survival in patients with pancreatic cancer. As neoadjuvant chemoradiation is established for the treatment of rectal cancer we examined the value of neoadjuvant chemoradiotherapy in pancreatic cancer in a randomized phase II trial. Radiological staging defining resectability was basic information prior to randomization in contrast to adjuvant therapy trials resting on pathological staging. Patients with resectable adenocarcinoma of the pancreatic head were randomized to primary surgery (Arm A) or neoadjuvant chemoradiotherapy followed by surgery (Arm B), which was followed by adjuvant chemotherapy in both arms. A total of 254 patients were required to detect a 4.33-month improvement in median overall survival (mOS). The trial was stopped after 73 patients; 66 patients were eligible for analysis. Twenty nine of 33 allocated patients received chemoradiotherapy. Radiotherapy was completed in all patients. Chemotherapy was changed in 3 patients due to toxicity. Tumor resection was performed in 23 vs. 19 patients (A vs. B). The R0 resection rate was 48 % (A) and 52 % (B, P = 0.81) and (y)pN0 was 30 % (A) vs. 39 % (B, P = 0.44), respectively. Postoperative complications were comparable in both groups. mOS was 14.4 vs. 17.4 months (A vs. B; intention-to-treat analysis; P = 0.96). After tumor resection, mOS was 18.9 vs. 25.0 months (A vs. B; P = 0.79). This worldwide first randomized trial for neoadjuvant chemoradiotherapy in pancreatic cancer showed that neoadjuvant chemoradiation is safe with respect to toxicity, perioperative morbidity, and mortality. Nevertheless, the trial was terminated early due to slow recruiting and the results were not significant. ISRCTN78805636; NCT00335543. (orig.) [de

The effectiveness of propolis on gingivitis: a randomized controlled trial.

Science.gov (United States)

Bretz, Walter A; Paulino, Niraldo; Nör, Jacques E; Moreira, Alexandre

2014-12-01

A randomized, double-blind, controlled clinical trial was conducted to evaluate the effectiveness of a propolis rinse on induced gingivitis by using the co-twin study design. Twenty-one twin pairs (n=42) were enrolled in a gingivitis study with oral hygiene promotion (14 days) and gingivitis induction (21 days). During the gingivitis induction phase, one member of the twin pair was randomly assigned to a 2% typified propolis rinse, and the other was assigned a color-matched 0.05% sodium fluoride plus 0.05% cetylpyridinium chloride rinse (positive control). Patients rinsed twice daily with 20 mL for 30 seconds for 21 days. Gingivitis was measured on days -14 (baseline), 0 (after hygiene phase), and 21 (after no-hygiene phase) by using the Papillary Bleeding Score (PBS) and by standard digital imaging of the gum tissues (G-parameter). The 38 persons who completed the study (age 13-22 years) were well balanced according to PBS at baseline and G-parameter after the initial hygiene phase. After 21 days without oral hygiene, the propolis rinse and positive control rinse groups did not differ significantly for average PBS measurements or G-parameter. Use of a 2% typified propolis rinse was equivalent to a positive control rinse during a 21-day no-hygiene period.

On random unitary channels

International Nuclear Information System (INIS)

Audenaert, Koenraad M R; Scheel, Stefan

2008-01-01

In this paper, we provide necessary and sufficient conditions for a completely positive trace-preserving (CPT) map to be decomposable into a convex combination of unitary maps. Additionally, we set out to define a proper distance measure between a given CPT map and the set of random unitary maps, and methods for calculating it. In this way one could determine whether non-classical error mechanisms such as spontaneous decay or photon loss dominate over classical uncertainties, for example, in a phase parameter. The present paper is a step towards achieving this goal

Phase-space diffusion in turbulent plasmas: The random acceleration problem revisited

DEFF Research Database (Denmark)

Pécseli, H.L.; Trulsen, J.

1991-01-01

Phase-space diffusion of test particles in turbulent plasmas is studied by an approach based on a conditional statistical analysis of fluctuating electrostatic fields. Analytical relations between relevant conditional averages and higher-order correlations, , and triple...

Radiofrequency ablation combined with systemic treatment versus systemic treatment alone in patients with non-resectable colorectal liver metastases: a randomized EORTC Intergroup phase II study (EORTC 40004).

Science.gov (United States)

Ruers, T; Punt, C; Van Coevorden, F; Pierie, J P E N; Borel-Rinkes, I; Ledermann, J A; Poston, G; Bechstein, W; Lentz, M A; Mauer, M; Van Cutsem, E; Lutz, M P; Nordlinger, B

2012-10-01

This study investigates the possible benefits of radiofrequency ablation (RFA) in patients with non-resectable colorectal liver metastases. This phase II study, originally started as a phase III design, randomly assigned 119 patients with non-resectable colorectal liver metastases between systemic treatment (n = 59) or systemic treatment plus RFA ( ± resection) (n = 60). Primary objective was a 30-month overall survival (OS) rate >38% for the combined treatment group. The primary end point was met, 30-month OS rate was 61.7% [95% confidence interval (CI) 48.2-73.9] for combined treatment. However, 30-month OS for systemic treatment was 57.6% (95% CI 44.1-70.4), higher than anticipated. Median OS was 45.3 for combined treatment and 40.5 months for systemic treatment (P = 0.22). PFS rate at 3 years for combined treatment was 27.6% compared with 10.6% for systemic treatment only (hazard ratio = 0.63, 95% CI 0.42-0.95, P = 0.025). Median progression-free survival (PFS) was 16.8 months (95% CI 11.7-22.1) and 9.9 months (95% CI 9.3-13.7), respectively. This is the first randomized study on the efficacy of RFA. The study met the primary end point on 30-month OS; however, the results in the control arm were in the same range. RFA plus systemic treatment resulted in significant longer PFS. At present, the ultimate effect of RFA on OS remains uncertain.

Probabilistic cloning of coherent states without a phase reference

DEFF Research Database (Denmark)

Müller, Christian R.; Wittmann, Christoffer; Marek, Petr

2012-01-01

We present a probabilistic cloning scheme operating independently of any phase reference. The scheme is based solely on a phase-randomized displacement and photon counting, omitting the need for nonclassical resources and nonlinear materials. In an experimental implementation, we employ the scheme...... to clone coherent states from a phase covariant alphabet and demonstrate that the cloner is capable of outperforming the hitherto best-performing deterministic scheme. An analysis of the covariances between the output states shows that uncorrelated clones can be approached asymptotically...