Lipschitz Regularity of Solutions for Mixed Integro-Differential Equations

OpenAIRE

Barles, Guy; Chasseigne, Emmanuel; Ciomaga, Adina; Imbert, Cyril

2011-01-01

We establish new Hoelder and Lipschitz estimates for viscosity solutions of a large class of elliptic and parabolic nonlinear integro-differential equations, by the classical Ishii-Lions's method. We thus extend the Hoelder regularity results recently obtained by Barles, Chasseigne and Imbert (2011). In addition, we deal with a new class of nonlocal equations that we term mixed integro-differential equations. These equations are particularly interesting, as they are degenerate both in the loc...

The Method of Lines Solution of the Regularized Long-Wave Equation Using Runge-Kutta Time Discretization Method

Directory of Open Access Journals (Sweden)

H. O. Bakodah

2013-01-01

Full Text Available A method of lines approach to the numerical solution of nonlinear wave equations typified by the regularized long wave (RLW is presented. The method developed uses a finite differences discretization to the space. Solution of the resulting system was obtained by applying fourth Runge-Kutta time discretization method. Using Von Neumann stability analysis, it is shown that the proposed method is marginally stable. To test the accuracy of the method some numerical experiments on test problems are presented. Test problems including solitary wave motion, two-solitary wave interaction, and the temporal evaluation of a Maxwellian initial pulse are studied. The accuracy of the present method is tested with and error norms and the conservation properties of mass, energy, and momentum under the RLW equation.

Neighborhood Regularized Logistic Matrix Factorization for Drug-Target Interaction Prediction.

Science.gov (United States)

Liu, Yong; Wu, Min; Miao, Chunyan; Zhao, Peilin; Li, Xiao-Li

2016-02-01

In pharmaceutical sciences, a crucial step of the drug discovery process is the identification of drug-target interactions. However, only a small portion of the drug-target interactions have been experimentally validated, as the experimental validation is laborious and costly. To improve the drug discovery efficiency, there is a great need for the development of accurate computational approaches that can predict potential drug-target interactions to direct the experimental verification. In this paper, we propose a novel drug-target interaction prediction algorithm, namely neighborhood regularized logistic matrix factorization (NRLMF). Specifically, the proposed NRLMF method focuses on modeling the probability that a drug would interact with a target by logistic matrix factorization, where the properties of drugs and targets are represented by drug-specific and target-specific latent vectors, respectively. Moreover, NRLMF assigns higher importance levels to positive observations (i.e., the observed interacting drug-target pairs) than negative observations (i.e., the unknown pairs). Because the positive observations are already experimentally verified, they are usually more trustworthy. Furthermore, the local structure of the drug-target interaction data has also been exploited via neighborhood regularization to achieve better prediction accuracy. We conducted extensive experiments over four benchmark datasets, and NRLMF demonstrated its effectiveness compared with five state-of-the-art approaches.

Corrosion phenomena in sodium-potassium coolant resulting from solute interaction in multicomponent solution

Science.gov (United States)

Krasin, V. P.; Soyustova, S. I.

2018-03-01

The solubility of Fe, Cr, Ni, V, Mn and Mo in sodium-potassium melt has been calculated using the mathematical framework of pseudo-regular solution model. The calculation results are compared with available published experimental data on mass transfer of components of austenitic stainless steel in sodium-potassium loop under non-isothermal conditions. It is shown that the parameters of pair interaction of oxygen with transition metal can be used to predict the corrosion behavior of structural materials in sodium-potassium melt in the presence of oxygen impurity. The results of calculation of threshold concentration of oxygen of ternary oxide formation of sodium with transitional metals (Fe, Cr, Ni, V, Mn, Mo) are given in conditions when pure solid metal comes in contact with sodium-potassium melt.

Scalar, electromagnetic, and gravitational fields interaction: Particlelike solutions

International Nuclear Information System (INIS)

Bronnikov, K.A.; Melnikov, V.N.; Shikin, G.N.; Staniukovich, K.P.

1979-01-01

Particlelike static spherically symmetric solutions to massless scalar and electromagnetic field equations combined with gravitational field equations are considered. Two criteria for particlelike solutions are formulated: the strong one (solutions are required to be singularity free) and the weak one (singularities are admitted but the total energy and material field energy should be finite). Exact solutions for the following physical systems are considered with their own gravitational field: (i) linear scalar (minimally coupled or conformal) plus electromagnetic field; (ii) the same fields with a bare mass source in the form of charged incoherent matter distributions; (iii) nonlinear electromagnetic field with an abritrary dependence on the invariant F/sub alphabeta/F/sup alphabeta/; and (iv) directly interacting scalar and electromagnetic fields. Case (i) solutions are not particlelike (except those with horizons, in which static regions formally satisfy the weak criterion). For systems (ii), examples of nonsingular models are constructed, in particular, a model for a particle--antiparticle pair of a Wheeler-handle type, without scalar field and explict electric charges. Besides, a number of limitations upon nonsingular model parameters is indicated. Systems (iii) are proved to violate the strong criterion for any type of nonlinearity but can satisfy the weak criterion (e.g., the Born--Infeld nonlinearity). For systems (iv) some particlelike solutions by the weak criterion are constructed and a regularizing role of gravitation is demonstrated. Finally, an example of a field system satisfying the strong criterion is given

The existence and regularity of time-periodic solutions to the three-dimensional Navier–Stokes equations in the whole space

International Nuclear Information System (INIS)

Kyed, Mads

2014-01-01

The existence, uniqueness and regularity of time-periodic solutions to the Navier–Stokes equations in the three-dimensional whole space are investigated. We consider the Navier–Stokes equations with a non-zero drift term corresponding to the physical model of a fluid flow around a body that moves with a non-zero constant velocity. The existence of a strong time-periodic solution is shown for small time-periodic data. It is further shown that this solution is unique in a large class of weak solutions that can be considered physically reasonable. Finally, we establish regularity properties for any strong solution regardless of its size. (paper)

The Role of the Pressure in the Partial Regularity Theory for Weak Solutions of the Navier-Stokes Equations

Science.gov (United States)

Chamorro, Diego; Lemarié-Rieusset, Pierre-Gilles; Mayoufi, Kawther

2018-04-01

We study the role of the pressure in the partial regularity theory for weak solutions of the Navier-Stokes equations. By introducing the notion of dissipative solutions, due to D uchon and R obert (Nonlinearity 13:249-255, 2000), we will provide a generalization of the Caffarelli, Kohn and Nirenberg theory. Our approach sheels new light on the role of the pressure in this theory in connection to Serrin's local regularity criterion.

Interactive telemedicine solution based on a secure mHealth application.

Science.gov (United States)

Eldeib, Ayman M

2014-01-01

In dynamic healthcare environments, caregivers and patients are constantly moving. To increase the healthcare quality when it is necessary, caregivers need the ability to reach each other and securely access medical information and services from wherever they happened to be. This paper presents an Interactive Telemedicine Solution (ITS) to facilitate and automate the communication within a healthcare facility via Voice over Internet Protocol (VOIP), regular mobile phones, and Wi-Fi connectivity. Our system has the capability to exchange/provide securely healthcare information/services across geographic barriers through 3G/4G wireless communication network. Our system assumes the availability of an Electronic Health Record (EHR) system locally in the healthcare organization and/or on the cloud network such as a nation-wide EHR system. This paper demonstrate the potential of our system to provide effectively and securely remote healthcare solution.

Interaction between parenting and neighborhood quality on the risk of adolescent regular smoking.

Science.gov (United States)

Wen, Xiaozhong; Shenassa, Edmond D

2012-03-01

To conduct the first study to examine potential interaction between parenting style and neighborhood quality on the risk of adolescent regular smoking. We analyzed data from a nationally representative sample of U.S. adolescents (n = 1,213 pairs of adolescents and their parents) who participated in the Panel Study of Income Dynamics during 2002-2003. Regular smoking behavior and parental monitoring level were reported by adolescents. Parenting style (i.e., authoritative, authoritarian, permissive, and uninvolved) was defined by cross-classifying self-reported parental warmth and control. Based on parents' perceived neighborhood quality regarding raising children, neighborhoods were identified as either higher quality or lower quality. Adolescents in lower-quality neighborhoods were more likely to be regular smokers (13.7% vs. 8.5%; adjusted odds ratio [AOR] = 1.93, 95% CI = 1.02-3.65) than those in higher-quality neighborhoods. In lower-quality neighborhoods, adolescents of authoritarian parents (16.9%; AOR = 10.97, 95% CI = 3.36-35.84) were more likely and those of uninvolved parents (20.3%; AOR = 3.47, 95% CI = 0.91-13.17) were marginally more likely to be regular smokers than those of authoritative parents (4.3%). However, among adolescents in higher-quality neighborhoods, parenting style was independent of the risk of regular smoking. There was marginally significant interaction between authoritarian parenting style and neighborhood quality. Parental monitoring was associated with reduced risk of adolescent smoking, regardless of neighborhood quality. There was no interaction between parental monitoring and neighborhood quality. Authoritative parenting is associated with reduced risk of adolescent regular smoking in lower-quality neighborhoods but not in higher-quality neighborhoods. Authoritative parenting style and parental monitoring may buffer adverse influences of low-quality neighborhood.

Magnetization processes in quantum spin chains with regularly alternating intersite interactions

International Nuclear Information System (INIS)

Derzhko, O.

2001-01-01

We consider the dependence of magnetization on field at zero temperature for spin-1/2 chains in which intersite interactions regularly vary from site to site with period p. In the limiting case, where the smallest value of the intersite interactions tends to zero, the chain splits into noninteracting identical fragments of p sites and the dependence of magnetization on field can be examined rigorously. We comment on the influence of an anisotropy in the inter spin interaction on the magnetization profiles. Finally, we show how the case of a nonzero smallest value of the intersite interactions can be considered

Drug-Target Interaction Prediction with Graph Regularized Matrix Factorization.

Science.gov (United States)

Ezzat, Ali; Zhao, Peilin; Wu, Min; Li, Xiao-Li; Kwoh, Chee-Keong

2017-01-01

Experimental determination of drug-target interactions is expensive and time-consuming. Therefore, there is a continuous demand for more accurate predictions of interactions using computational techniques. Algorithms have been devised to infer novel interactions on a global scale where the input to these algorithms is a drug-target network (i.e., a bipartite graph where edges connect pairs of drugs and targets that are known to interact). However, these algorithms had difficulty predicting interactions involving new drugs or targets for which there are no known interactions (i.e., "orphan" nodes in the network). Since data usually lie on or near to low-dimensional non-linear manifolds, we propose two matrix factorization methods that use graph regularization in order to learn such manifolds. In addition, considering that many of the non-occurring edges in the network are actually unknown or missing cases, we developed a preprocessing step to enhance predictions in the "new drug" and "new target" cases by adding edges with intermediate interaction likelihood scores. In our cross validation experiments, our methods achieved better results than three other state-of-the-art methods in most cases. Finally, we simulated some "new drug" and "new target" cases and found that GRMF predicted the left-out interactions reasonably well.

Regular non-twisting S-branes

International Nuclear Information System (INIS)

Obregon, Octavio; Quevedo, Hernando; Ryan, Michael P.

2004-01-01

We construct a family of time and angular dependent, regular S-brane solutions which corresponds to a simple analytical continuation of the Zipoy-Voorhees 4-dimensional vacuum spacetime. The solutions are asymptotically flat and turn out to be free of singularities without requiring a twist in space. They can be considered as the simplest non-singular generalization of the singular S0-brane solution. We analyze the properties of a representative of this family of solutions and show that it resembles to some extent the asymptotic properties of the regular Kerr S-brane. The R-symmetry corresponds, however, to the general lorentzian symmetry. Several generalizations of this regular solution are derived which include a charged S-brane and an additional dilatonic field. (author)

On the Anticipatory Aspects of the Four Interactions: what the Known Classical and Semi-Classical Solutions Teach us

International Nuclear Information System (INIS)

Lusanna, Luca

2004-01-01

The four (electro-magnetic, weak, strong and gravitational) interactions are described by singular Lagrangians and by Dirac-Bergmann theory of Hamiltonian constraints. As a consequence a subset of the original configuration variables are gauge variables, not determined by the equations of motion. Only at the Hamiltonian level it is possible to separate the gauge variables from the deterministic physical degrees of freedom, the Dirac observables, and to formulate a well posed Cauchy problem for them both in special and general relativity. Then the requirement of causality dictates the choice of retarded solutions at the classical level. However both the problems of the classical theory of the electron, leading to the choice of (1/2) (retarded + advanced) solutions, and the regularization of quantum field theory, leading to the Feynman propagator, introduce anticipatory aspects. The determination of the relativistic Darwin potential as a semi-classical approximation to the Lienard-Wiechert solution for particles with Grassmann-valued electric charges, regularizing the Coulomb self-energies, shows that these anticipatory effects live beyond the semi-classical approximation (tree level) under the form of radiative corrections, at least for the electro-magnetic interaction.Talk and 'best contribution' at The Sixth International Conference on Computing Anticipatory Systems CASYS'03, Liege August 11-16, 2003

Asymptotics of decreasing solutions of coupled p-Laplacian systems in the framework of regular variation

Czech Academy of Sciences Publication Activity Database

Řehák, Pavel; Matucci, S.

2014-01-01

Roč. 193, č. 3 (2014), s. 837-858 ISSN 0373-3114 Institutional support: RVO:67985840 Keywords : decreasing solution * quasilinear system * Emden-Fowler system * Lane-Emden system * regular variation Subject RIV: BA - General Mathematics Impact factor: 1.065, year: 2014 http://link.springer.com/article/10.1007%2Fs10231-012-0303-9

Robustness of regularities for energy centroids in the presence of random interactions

International Nuclear Information System (INIS)

Zhao, Y.M.; Arima, A.; Yoshida, N.; Ogawa, K.; Yoshinaga, N.; Kota, V. K. B.

2005-01-01

In this paper we study energy centroids such as those with fixed spin and isospin and those with fixed irreducible representations for both bosons and fermions, in the presence of random two-body and/or three-body interactions. Our results show that regularities of energy centroids of fixed-spin states reported in earlier works are very robust in these more complicated cases. We suggest that these behaviors might be intrinsic features of quantum many-body systems interacting by random forces

On the regularity of mild solutions to complete higher order differential equations on Banach spaces

Directory of Open Access Journals (Sweden)

Nezam Iraniparast

2015-09-01

Full Text Available For the complete higher order differential equation u(n(t=Σk=0n-1Aku(k(t+f(t, t∈ R (* on a Banach space E, we give a new definition of mild solutions of (*. We then characterize the regular admissibility of a translation invariant subspace al M of BUC(R, E with respect to (* in terms of solvability of the operator equation Σj=0n-1AjXal Dj-Xal Dn = C. As application, almost periodicity of mild solutions of (* is proved.

Interactive facades analysis and synthesis of semi-regular facades

KAUST Repository

AlHalawani, Sawsan; Yang, Yongliang; Liu, Han; Mitra, Niloy J.

2013-01-01

Urban facades regularly contain interesting variations due to allowed deformations of repeated elements (e.g., windows in different open or close positions) posing challenges to state-of-the-art facade analysis algorithms. We propose a semi-automatic framework to recover both repetition patterns of the elements and their individual deformation parameters to produce a factored facade representation. Such a representation enables a range of applications including interactive facade images, improved multi-view stereo reconstruction, facade-level change detection, and novel image editing possibilities. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.

Interactive facades analysis and synthesis of semi-regular facades

KAUST Repository

AlHalawani, Sawsan

2013-05-01

Urban facades regularly contain interesting variations due to allowed deformations of repeated elements (e.g., windows in different open or close positions) posing challenges to state-of-the-art facade analysis algorithms. We propose a semi-automatic framework to recover both repetition patterns of the elements and their individual deformation parameters to produce a factored facade representation. Such a representation enables a range of applications including interactive facade images, improved multi-view stereo reconstruction, facade-level change detection, and novel image editing possibilities. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.

Energy Distribution of a Regular Black Hole Solution in Einstein-Nonlinear Electrodynamics

Directory of Open Access Journals (Sweden)

I. Radinschi

2015-01-01

Full Text Available A study about the energy momentum of a new four-dimensional spherically symmetric, static and charged, regular black hole solution developed in the context of general relativity coupled to nonlinear electrodynamics is presented. Asymptotically, this new black hole solution behaves as the Reissner-Nordström solution only for the particular value μ=4, where μ is a positive integer parameter appearing in the mass function of the solution. The calculations are performed by use of the Einstein, Landau-Lifshitz, Weinberg, and Møller energy momentum complexes. In all the aforementioned prescriptions, the expressions for the energy of the gravitating system considered depend on the mass M of the black hole, its charge q, a positive integer α, and the radial coordinate r. In all these pseudotensorial prescriptions, the momenta are found to vanish, while the Landau-Lifshitz and Weinberg prescriptions give the same result for the energy distribution. In addition, the limiting behavior of the energy for the cases r→∞, r→0, and q=0 is studied. The special case μ=4 and α=3 is also examined. We conclude that the Einstein and Møller energy momentum complexes can be considered as the most reliable tools for the study of the energy momentum localization of a gravitating system.

Time-Homogeneous Parabolic Wick-Anderson Model in One Space Dimension: Regularity of Solution

OpenAIRE

Kim, Hyun-Jung; Lototsky, Sergey V

2017-01-01

Even though the heat equation with random potential is a well-studied object, the particular case of time-independent Gaussian white noise in one space dimension has yet to receive the attention it deserves. The paper investigates the stochastic heat equation with space-only Gaussian white noise on a bounded interval. The main result is that the space-time regularity of the solution is the same for additive noise and for multiplicative noise in the Wick-It\\^o-Skorokhod interpretation.

A note on local interior regularity of a suitable weak solution to the Navier--Stokes problem

Czech Academy of Sciences Publication Activity Database

Neustupa, Jiří

2013-01-01

Roč. 6, č. 5 (2013), s. 1391-1400 ISSN 1937-1632 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : Navier-Stokes equations * suitable weak solution * regularity Subject RIV: BA - General Mathematics http://aimsciences.org/journals/displayArticlesnew.jsp?paperID=8344

Prediction of thermodynamic properties of solute elements in Si solutions using first-principles calculations

International Nuclear Information System (INIS)

Iwata, K.; Matsumiya, T.; Sawada, H.; Kawakami, K.

2003-01-01

The method is presented to predict the activity coefficients and the interaction parameters of the solute elements in infinite dilute Si solutions by the use of first-principles calculations based on density functional theory. In this method, the regular solution model is assumed. The calculated activity coefficients in solid Si are converted to those in molten Si by the use of the solid-liquid partition coefficients. Furthermore, the interaction parameters in solid Si solutions are calculated and compared with reported experimental values of those in liquid Si solutions. The results show that the calculated activity coefficients and interaction parameters of Al, Fe, Ti and Pb in Si solutions are in good agreement with the tendency of the experiments. However, the calculations have some quantitative discrepancy from the experiments. It is expected that consideration of the excess entropy would reduce this discrepancy

Regular Bulk Solutions in Brane-Worlds with Inhomogeneous Dust and Generalized Dark Radiation

International Nuclear Information System (INIS)

Rocha, Roldão da; Kuerten, A. M.; Herrera-Aguilar, A.

2015-01-01

From the dynamics of a brane-world with matter fields present in the bulk, the bulk metric and the black string solution near the brane are generalized, when both the dynamics of inhomogeneous dust/generalized dark radiation on the brane-world and inhomogeneous dark radiation in the bulk as well are considered as exact dynamical collapse solutions. Based on the analysis on the inhomogeneous static exterior of a collapsing sphere of homogeneous dark radiation on the brane, the associated black string warped horizon is studied, as well as the 5D bulk metric near the brane. Moreover, the black string and the bulk are shown to be more regular upon time evolution, for suitable values for the dark radiation parameter in the model, by analyzing the soft physical singularities

Point interactions of the dipole type defined through a three-parametric power regularization

International Nuclear Information System (INIS)

Zolotaryuk, A V

2010-01-01

A family of point interactions of the dipole type is studied in one dimension using a regularization by rectangles in the form of a barrier and a well separated by a finite distance. The rectangles and the distance are parametrized by a squeezing parameter ε → 0 with three powers μ, ν and τ describing the squeezing rates for the barrier, the well and the distance, respectively. This parametrization allows us to construct a whole family of point potentials of the dipole type including some other point interactions, such as e.g. δ-potentials. Varying the power τ, it is possible to obtain in the zero-range limit the following two cases: (i) the limiting δ'-potential is opaque (the conventional result obtained earlier by some authors) or (ii) this potential admits a resonant tunneling (the opposite result obtained recently by other authors). The structure of resonances (if any) also depends on a regularizing sequence. The sets of the {μ, ν, τ}-space where a non-zero (resonant or non-resonant) transmission occurs are found. For all these cases in the zero-range limit the transfer matrix is shown to be with real parameters χ and g depending on a regularizing sequence. Those cases when χ ≠ 1 and g ≠ 0 mean that the corresponding δ'-potential is accompanied by an effective δ-potential.

Decay property of regularity-loss type of solutions in elastic solids with voids

KAUST Repository

Said-Houari, Belkacem; Messaoudi, Salim A.

2013-01-01

In this article, we consider two porous systems of nonclassical thermoelasticity in the whole real line. We discuss the long-time behaviour of the solutions in the presence of a strong damping acting, together with the heat effect, on the elastic equation and establish several decay results. Those decay results are shown to be very slow and of regularity-loss type. Some improvements of the decay rates have also been given, provided that the initial data belong to some weighted spaces. © 2013 Copyright Taylor and Francis Group, LLC.

Decay property of regularity-loss type of solutions in elastic solids with voids

KAUST Repository

Said-Houari, Belkacem

2013-12-01

In this article, we consider two porous systems of nonclassical thermoelasticity in the whole real line. We discuss the long-time behaviour of the solutions in the presence of a strong damping acting, together with the heat effect, on the elastic equation and establish several decay results. Those decay results are shown to be very slow and of regularity-loss type. Some improvements of the decay rates have also been given, provided that the initial data belong to some weighted spaces. © 2013 Copyright Taylor and Francis Group, LLC.

Abundant Interaction Solutions of Sine-Gordon Equation

Directory of Open Access Journals (Sweden)

DaZhao Lü

2012-01-01

Full Text Available With the help of computer symbolic computation software (e.g., Maple, abundant interaction solutions of sine-Gordon equation are obtained by means of a constructed Wronskian form expansion method. The method is based upon the forms and structures of Wronskian solutions of sine-Gordon equation, and the functions used in the Wronskian determinants do not satisfy linear partial differential equations. Such interaction solutions are difficultly obtained via other methods. And the method can be automatically carried out in computer.

On geodesics in low regularity

Science.gov (United States)

Sämann, Clemens; Steinbauer, Roland

2018-02-01

We consider geodesics in both Riemannian and Lorentzian manifolds with metrics of low regularity. We discuss existence of extremal curves for continuous metrics and present several old and new examples that highlight their subtle interrelation with solutions of the geodesic equations. Then we turn to the initial value problem for geodesics for locally Lipschitz continuous metrics and generalize recent results on existence, regularity and uniqueness of solutions in the sense of Filippov.

Drug-drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer.

Science.gov (United States)

Park, Gab-Jin; Bae, Soo Hyeon; Park, Wan-Su; Han, Seunghoon; Park, Min-Ho; Shin, Seok-Ho; Shin, Young G; Yim, Dong-Seok

2017-01-01

A microdose drug-drug interaction (DDI) study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim) and known perpetrators: fluconazole (inhibitor) and rifampin (inducer). For both studies, the microdose (100 μg, cold compound) and the regular dose (20 mg) of omeprazole were given at days 0 and 1, respectively. On days 2-9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis. The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only) of maximum concentration (C max ) and area under the curve to the last measurement (AUC t ) of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro) and 2.68 (regular) for C max , and 4.07 (micro), 4.33 (regular) for AUC t . For the induction study, they were 0.26 (micro) and 0.21 (regular) for C max , and 0.16 (micro) and 0.15 (regular) for AUC t . There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Our results may be used as partial evidence that microdose DDI studies may replace regular-dose studies, or at least be used for DDI-screening purposes.

Exact Solution of the Gyration Radius of an Individual's Trajectory for a Simplified Human Regular Mobility Model

Science.gov (United States)

Yan, Xiao-Yong; Han, Xiao-Pu; Zhou, Tao; Wang, Bing-Hong

2011-12-01

We propose a simplified human regular mobility model to simulate an individual's daily travel with three sequential activities: commuting to workplace, going to do leisure activities and returning home. With the assumption that the individual has a constant travel speed and inferior limit of time at home and in work, we prove that the daily moving area of an individual is an ellipse, and finally obtain an exact solution of the gyration radius. The analytical solution captures the empirical observation well.

Drug–drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer

Directory of Open Access Journals (Sweden)

Park G

2017-03-01

Full Text Available Gab-jin Park,1 Soo Hyeon Bae,1 Wan-Su Park,1 Seunghoon Han,1 Min-Ho Park,2 Seok-Ho Shin,2 Young G Shin,2 Dong-Seok Yim1,2 1Department of Clinical Pharmacology and Therapeutics, Seoul St Mary’s Hospital, PIPET (Pharmacometrics Institute for Practical Education and Training, College of Medicine, Catholic University of Korea, Seoul, South Korea; 2College of Pharmacy, Chungnam National University, Daejeon, South Korea Purpose: A microdose drug–drug interaction (DDI study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Patients and methods: Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim and known perpetrators: fluconazole (inhibitor and rifampin (inducer. For both studies, the microdose (100 µg, cold compound and the regular dose (20 mg of omeprazole were given at days 0 and 1, respectively. On days 2–9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis. Results: The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only of maximum concentration (Cmax and area under the curve to the last measurement (AUCt of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro and 2.68 (regular for Cmax, and 4.07 (micro, 4.33 (regular for AUCt. For the induction study, they were 0.26 (micro and 0.21 (regular for Cmax, and 0.16 (micro and 0.15 (regular for AUCt. There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Conclusion: Our results may be

A regularized stationary mean-field game

KAUST Repository

Yang, Xianjin

2016-01-01

In the thesis, we discuss the existence and numerical approximations of solutions of a regularized mean-field game with a low-order regularization. In the first part, we prove a priori estimates and use the continuation method to obtain the existence of a solution with a positive density. Finally, we introduce the monotone flow method and solve the system numerically.

A regularized stationary mean-field game

KAUST Repository

Yang, Xianjin

2016-04-19

In the thesis, we discuss the existence and numerical approximations of solutions of a regularized mean-field game with a low-order regularization. In the first part, we prove a priori estimates and use the continuation method to obtain the existence of a solution with a positive density. Finally, we introduce the monotone flow method and solve the system numerically.

Regularizing portfolio optimization

International Nuclear Information System (INIS)

Still, Susanne; Kondor, Imre

2010-01-01

The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theory. The occurrence of the instability is intimately related to over-fitting, which can be avoided using known regularization methods. We show how regularized portfolio optimization with the expected shortfall as a risk measure is related to support vector regression. The budget constraint dictates a modification. We present the resulting optimization problem and discuss the solution. The L2 norm of the weight vector is used as a regularizer, which corresponds to a diversification 'pressure'. This means that diversification, besides counteracting downward fluctuations in some assets by upward fluctuations in others, is also crucial because it improves the stability of the solution. The approach we provide here allows for the simultaneous treatment of optimization and diversification in one framework that enables the investor to trade off between the two, depending on the size of the available dataset.

Regularizing portfolio optimization

Science.gov (United States)

Still, Susanne; Kondor, Imre

2010-07-01

The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theory. The occurrence of the instability is intimately related to over-fitting, which can be avoided using known regularization methods. We show how regularized portfolio optimization with the expected shortfall as a risk measure is related to support vector regression. The budget constraint dictates a modification. We present the resulting optimization problem and discuss the solution. The L2 norm of the weight vector is used as a regularizer, which corresponds to a diversification 'pressure'. This means that diversification, besides counteracting downward fluctuations in some assets by upward fluctuations in others, is also crucial because it improves the stability of the solution. The approach we provide here allows for the simultaneous treatment of optimization and diversification in one framework that enables the investor to trade off between the two, depending on the size of the available dataset.

Improvements in GRACE Gravity Fields Using Regularization

Science.gov (United States)

Save, H.; Bettadpur, S.; Tapley, B. D.

2008-12-01

The unconstrained global gravity field models derived from GRACE are susceptible to systematic errors that show up as broad "stripes" aligned in a North-South direction on the global maps of mass flux. These errors are believed to be a consequence of both systematic and random errors in the data that are amplified by the nature of the gravity field inverse problem. These errors impede scientific exploitation of the GRACE data products, and limit the realizable spatial resolution of the GRACE global gravity fields in certain regions. We use regularization techniques to reduce these "stripe" errors in the gravity field products. The regularization criteria are designed such that there is no attenuation of the signal and that the solutions fit the observations as well as an unconstrained solution. We have used a computationally inexpensive method, normally referred to as "L-ribbon", to find the regularization parameter. This paper discusses the characteristics and statistics of a 5-year time-series of regularized gravity field solutions. The solutions show markedly reduced stripes, are of uniformly good quality over time, and leave little or no systematic observation residuals, which is a frequent consequence of signal suppression from regularization. Up to degree 14, the signal in regularized solution shows correlation greater than 0.8 with the un-regularized CSR Release-04 solutions. Signals from large-amplitude and small-spatial extent events - such as the Great Sumatra Andaman Earthquake of 2004 - are visible in the global solutions without using special post-facto error reduction techniques employed previously in the literature. Hydrological signals as small as 5 cm water-layer equivalent in the small river basins, like Indus and Nile for example, are clearly evident, in contrast to noisy estimates from RL04. The residual variability over the oceans relative to a seasonal fit is small except at higher latitudes, and is evident without the need for de-striping or

Noncovalent Interactions between Dopamine and Regular and Defective Graphene.

Science.gov (United States)

Fernández, Ana C Rossi; Castellani, Norberto J

2017-08-05

The role of noncovalent interactions in the adsorption of biological molecules on graphene is a subject of fundamental interest regarding the use of graphene as a material for sensing and drug delivery. The adsorption of dopamine on regular graphene and graphene with monovacancies (GV) is theoretically studied within the framework of density functional theory. Several adsorption modes are considered, and notably those in which the dopamine molecule is oriented parallel or quasi-parallel to the surface are the more stable. The adsorption of dopamine on graphene implies an attractive interaction of a dispersive nature that competes with Pauli repulsion between the occupied π orbitals of the dopamine ring and the π orbitals of graphene. If dopamine adsorbs at the monovacancy in the A-B stacking mode, a hydrogen bond is produced between one of the dopamine hydroxy groups and one carbon atom around the vacancy. The electronic charge redistribution due to adsorption is consistent with an electronic drift from the graphene or GV surface to the dopamine molecule. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Existence, regularity and representation of solutions of time fractional wave equations

Directory of Open Access Journals (Sweden)

Valentin Keyantuo

2017-09-01

Full Text Available We study the solvability of the fractional order inhomogeneous Cauchy problem $$ \\mathbb{D}_t^\\alpha u(t=Au(t+f(t, \\quad t>0,\\;1<\\alpha\\le 2, $$ where A is a closed linear operator in some Banach space X and $f:[0,\\infty\\to X$ a given function. Operator families associated with this problem are defined and their regularity properties are investigated. In the case where A is a generator of a $\\beta$-times integrated cosine family $(C_\\beta(t$, we derive explicit representations of mild and classical solutions of the above problem in terms of the integrated cosine family. We include applications to elliptic operators with Dirichlet, Neumann or Robin type boundary conditions on $L^p$-spaces and on the space of continuous functions.

Drug–drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer

Science.gov (United States)

Park, Gab-jin; Bae, Soo Hyeon; Park, Wan-Su; Han, Seunghoon; Park, Min-Ho; Shin, Seok-Ho; Shin, Young G; Yim, Dong-Seok

2017-01-01

Purpose A microdose drug–drug interaction (DDI) study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Patients and methods Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim) and known perpetrators: fluconazole (inhibitor) and rifampin (inducer). For both studies, the microdose (100 μg, cold compound) and the regular dose (20 mg) of omeprazole were given at days 0 and 1, respectively. On days 2–9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis. Results The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only) of maximum concentration (Cmax) and area under the curve to the last measurement (AUCt) of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro) and 2.68 (regular) for Cmax, and 4.07 (micro), 4.33 (regular) for AUCt. For the induction study, they were 0.26 (micro) and 0.21 (regular) for Cmax, and 0.16 (micro) and 0.15 (regular) for AUCt. There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Conclusion Our results may be used as partial evidence that microdose DDI studies may replace regular-dose studies, or at least be used for DDI-screening purposes. PMID:28408803

Applications of exact traveling wave solutions of Modified Liouville and the Symmetric Regularized Long Wave equations via two new techniques

Science.gov (United States)

Lu, Dianchen; Seadawy, Aly R.; Ali, Asghar

2018-06-01

In this current work, we employ novel methods to find the exact travelling wave solutions of Modified Liouville equation and the Symmetric Regularized Long Wave equation, which are called extended simple equation and exp(-Ψ(ξ))-expansion methods. By assigning the different values to the parameters, different types of the solitary wave solutions are derived from the exact traveling wave solutions, which shows the efficiency and precision of our methods. Some solutions have been represented by graphical. The obtained results have several applications in physical science.

Learning regularization parameters for general-form Tikhonov

International Nuclear Information System (INIS)

Chung, Julianne; Español, Malena I

2017-01-01

Computing regularization parameters for general-form Tikhonov regularization can be an expensive and difficult task, especially if multiple parameters or many solutions need to be computed in real time. In this work, we assume training data is available and describe an efficient learning approach for computing regularization parameters that can be used for a large set of problems. We consider an empirical Bayes risk minimization framework for finding regularization parameters that minimize average errors for the training data. We first extend methods from Chung et al (2011 SIAM J. Sci. Comput. 33 3132–52) to the general-form Tikhonov problem. Then we develop a learning approach for multi-parameter Tikhonov problems, for the case where all involved matrices are simultaneously diagonalizable. For problems where this is not the case, we describe an approach to compute near-optimal regularization parameters by using operator approximations for the original problem. Finally, we propose a new class of regularizing filters, where solutions correspond to multi-parameter Tikhonov solutions, that requires less data than previously proposed optimal error filters, avoids the generalized SVD, and allows flexibility and novelty in the choice of regularization matrices. Numerical results for 1D and 2D examples using different norms on the errors show the effectiveness of our methods. (paper)

Incremental projection approach of regularization for inverse problems

Energy Technology Data Exchange (ETDEWEB)

Souopgui, Innocent, E-mail: innocent.souopgui@usm.edu [The University of Southern Mississippi, Department of Marine Science (United States); Ngodock, Hans E., E-mail: hans.ngodock@nrlssc.navy.mil [Naval Research Laboratory (United States); Vidard, Arthur, E-mail: arthur.vidard@imag.fr; Le Dimet, François-Xavier, E-mail: ledimet@imag.fr [Laboratoire Jean Kuntzmann (France)

2016-10-15

This paper presents an alternative approach to the regularized least squares solution of ill-posed inverse problems. Instead of solving a minimization problem with an objective function composed of a data term and a regularization term, the regularization information is used to define a projection onto a convex subspace of regularized candidate solutions. The objective function is modified to include the projection of each iterate in the place of the regularization. Numerical experiments based on the problem of motion estimation for geophysical fluid images, show the improvement of the proposed method compared with regularization methods. For the presented test case, the incremental projection method uses 7 times less computation time than the regularization method, to reach the same error target. Moreover, at convergence, the incremental projection is two order of magnitude more accurate than the regularization method.

Particle-like solutions of the Einstein-Dirac-Maxwell equations

Science.gov (United States)

Finster, Felix; Smoller, Joel; Yau, Shing-Tung

1999-08-01

We consider the coupled Einstein-Dirac-Maxwell equations for a static, spherically symmetric system of two fermions in a singlet spinor state. Soliton-like solutions are constructed numerically. The stability and the properties of the ground state solutions are discussed for different values of the electromagnetic coupling constant. We find solutions even when the electromagnetic coupling is so strong that the total interaction is repulsive in the Newtonian limit. Our solutions are regular and well-behaved; this shows that the combined electromagnetic and gravitational self-interaction of the Dirac particles is finite.

Asymptotic analysis of a pile-up of regular edge dislocation walls

KAUST Repository

Hall, Cameron L.

2011-12-01

The idealised problem of a pile-up of regular dislocation walls (that is, of planes each containing an infinite number of parallel, identical and equally spaced dislocations) was presented by Roy et al. [A. Roy, R.H.J. Peerlings, M.G.D. Geers, Y. Kasyanyuk, Materials Science and Engineering A 486 (2008) 653-661] as a prototype for understanding the importance of discrete dislocation interactions in dislocation-based plasticity models. They noted that analytic solutions for the dislocation wall density are available for a pile-up of regular screw dislocation walls, but that numerical methods seem to be necessary for investigating regular edge dislocation walls. In this paper, we use the techniques of discrete-to-continuum asymptotic analysis to obtain a detailed description of a pile-up of regular edge dislocation walls. To leading order, we find that the dislocation wall density is governed by a simple differential equation and that boundary layers are present at both ends of the pile-up. © 2011 Elsevier B.V.

Asymptotic analysis of a pile-up of regular edge dislocation walls

KAUST Repository

Hall, Cameron L.

2011-01-01

The idealised problem of a pile-up of regular dislocation walls (that is, of planes each containing an infinite number of parallel, identical and equally spaced dislocations) was presented by Roy et al. [A. Roy, R.H.J. Peerlings, M.G.D. Geers, Y. Kasyanyuk, Materials Science and Engineering A 486 (2008) 653-661] as a prototype for understanding the importance of discrete dislocation interactions in dislocation-based plasticity models. They noted that analytic solutions for the dislocation wall density are available for a pile-up of regular screw dislocation walls, but that numerical methods seem to be necessary for investigating regular edge dislocation walls. In this paper, we use the techniques of discrete-to-continuum asymptotic analysis to obtain a detailed description of a pile-up of regular edge dislocation walls. To leading order, we find that the dislocation wall density is governed by a simple differential equation and that boundary layers are present at both ends of the pile-up. © 2011 Elsevier B.V.

Lavrentiev regularization method for nonlinear ill-posed problems

International Nuclear Information System (INIS)

Kinh, Nguyen Van

2002-10-01

In this paper we shall be concerned with Lavientiev regularization method to reconstruct solutions x 0 of non ill-posed problems F(x)=y o , where instead of y 0 noisy data y δ is an element of X with absolut(y δ -y 0 ) ≤ δ are given and F:X→X is an accretive nonlinear operator from a real reflexive Banach space X into itself. In this regularization method solutions x α δ are obtained by solving the singularly perturbed nonlinear operator equation F(x)+α(x-x*)=y δ with some initial guess x*. Assuming certain conditions concerning the operator F and the smoothness of the element x*-x 0 we derive stability estimates which show that the accuracy of the regularized solutions is order optimal provided that the regularization parameter α has been chosen properly. (author)

Regularities in Low-Temperature Phosphatization of Silicates

Science.gov (United States)

Savenko, A. V.

2018-01-01

The regularities in low-temperature phosphatization of silicates are defined from long-term experiments on the interaction between different silicate minerals and phosphate-bearing solutions in a wide range of medium acidity. It is shown that the parameters of the reaction of phosphatization of hornblende, orthoclase, and labradorite have the same values as for clayey minerals (kaolinite and montmorillonite). This effect may appear, if phosphotization proceeds, not after silicate minerals with a different structure and composition, but after a secondary silicate phase formed upon interaction between silicates and water and stable in a certain pH range. Variation in the parameters of the reaction of phosphatization at pH ≈ 1.8 is due to the stability of the silicate phase different from that at higher pH values.

Solute-matrix and Solute-Solute Interactions during Supercritical Fluid Extraction of Sea Buckthorn Leaves

Czech Academy of Sciences Publication Activity Database

Sajfrtová, Marie; Sovová, Helena

2012-01-01

Roč. 42, SI (2012), s. 1682-1691 E-ISSN 1877-7058. [International Congress of Chemical and Process Engineering CHISA 2012 and 15th Conference PRES 2012 /20./. Prague, 25.08.2012-29.08.2012] R&D Projects: GA TA ČR TA01010578 Institutional support: RVO:67985858 Keywords : supercritical fluid extraction * sea buckthom leaves * solute-solute interaction Subject RIV: CI - Industrial Chemistry, Chemical Engineering

Regularization Tools Version 3.0 for Matlab 5.2

DEFF Research Database (Denmark)

Hansen, Per Christian

1999-01-01

This communication describes Version 3.0 of Regularization Tools, a Matlab package for analysis and solution of discrete ill-posed problems.......This communication describes Version 3.0 of Regularization Tools, a Matlab package for analysis and solution of discrete ill-posed problems....

Construction of normal-regular decisions of Bessel typed special system

Science.gov (United States)

Tasmambetov, Zhaksylyk N.; Talipova, Meiramgul Zh.

2017-09-01

Studying a special system of differential equations in the separate production of the second order is solved by the degenerate hypergeometric function reducing to the Bessel functions of two variables. To construct a solution of this system near regular and irregular singularities, we use the method of Frobenius-Latysheva applying the concepts of rank and antirank. There is proved the basic theorem that establishes the existence of four linearly independent solutions of studying system type of Bessel. To prove the existence of normal-regular solutions we establish necessary conditions for the existence of such solutions. The existence and convergence of a normally regular solution are shown using the notion of rank and antirank.

Classroom Interaction in Regular and Special Education Middle Primary Classrooms in the United Arab Emirates

Science.gov (United States)

Dukmak, Samir

2010-01-01

Samir Dukmak is an assistant professor in the Department of Special Education in the Faculty of Education at the United Arab Emirates University. The research reported in this article investigated the frequency, types of and reasons for student-initiated interactions in both regular and special education classrooms in the United Arab Emirates…

Aqueous solutions/nuclear glasses interactions

International Nuclear Information System (INIS)

Delage, F.; Advocat, T.; Vernaz, E.; Crovisier, J.L.

1991-01-01

Interactions results of the borosilicate glass used in radioactive wastes confinement and aqueous solutions at various temperature and PH show that for the glass components: - the release rate evolution follows an Arrhenius law, - in acid PH, there is a selective dissolution, - in basic PH, there is a stoechiometric dissolution [fr

Opalescence in monoclonal antibody solutions and its correlation with intermolecular interactions in dilute and concentrated solutions.

Science.gov (United States)

Raut, Ashlesha S; Kalonia, Devendra S

2015-04-01

Opalescence indicates physical instability of a formulation because of the presence of aggregates or liquid-liquid phase separation in solution and has been reported for monoclonal antibody (mAb) formulations. Increased solution opalescence can be attributed to attractive protein-protein interactions (PPIs). Techniques including light scattering, AUC, or membrane osmometry are routinely employed to measure PPIs in dilute solutions, whereas opalescence is seen at relatively higher concentrations, where both long- and short-range forces contribute to overall PPIs. The mAb molecule studied here shows a unique property of high opalescence because of liquid-liquid phase separation. In this study, opalescence measurements are correlated to PPIs measured in diluted and concentrated solutions using light scattering (kD ) and high-frequency rheology (G'), respectively. Charges on the molecules were calculated using zeta potential measurements. Results indicate that high opalescence and phase separation are a result of the attractive interactions in solution; however, the presence of attractive interactions do not always imply phase separation. Temperature dependence of opalescence suggests that thermodynamic contribution to opalescence is significant and Tcloud can be utilized as a potential tool to assess attractive interactions in solution. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

A geometric improvement of the velocity-pressure local regularity criterion for a suitable weak solution to the Navier-Stokes equations

Czech Academy of Sciences Publication Activity Database

Neustupa, Jiří

2014-01-01

Roč. 139, č. 4 (2014), s. 685-698 ISSN 0862-7959 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : Navier-Stokes equation * suitable weak solution * regularity Subject RIV: BA - General Mathematics http://hdl.handle.net/10338.dmlcz/144145

Dependence of Interaction Free Energy between Solutes on an External Electrostatic Field

Directory of Open Access Journals (Sweden)

Pei-Kun Yang

2013-07-01

Full Text Available To explore the athermal effect of an external electrostatic field on the stabilities of protein conformations and the binding affinities of protein-protein/ligand interactions, the dependences of the polar and hydrophobic interactions on the external electrostatic field, −Eext, were studied using molecular dynamics (MD simulations. By decomposing Eext into, along, and perpendicular to the direction formed by the two solutes, the effect of Eext on the interactions between these two solutes can be estimated based on the effects from these two components. Eext was applied along the direction of the electric dipole formed by two solutes with opposite charges. The attractive interaction free energy between these two solutes decreased for solutes treated as point charges. In contrast, the attractive interaction free energy between these two solutes increased, as observed by MD simulations, for Eext = 40 or 60 MV/cm. Eext was applied perpendicular to the direction of the electric dipole formed by these two solutes. The attractive interaction free energy was increased for Eext = 100 MV/cm as a result of dielectric saturation. The force on the solutes along the direction of Eext computed from MD simulations was greater than that estimated from a continuum solvent in which the solutes were treated as point charges. To explore the hydrophobic interactions, Eext was applied to a water cluster containing two neutral solutes. The repulsive force between these solutes was decreased/increased for Eext along/perpendicular to the direction of the electric dipole formed by these two solutes.

Regularity of a weak solution to the Navier--Stokes equations via one component of a spectral projection of vorticity

Czech Academy of Sciences Publication Activity Database

Neustupa, Jiří; Penel, P.

2014-01-01

Roč. 46, č. 2 (2014), s. 1681-1700 ISSN 0036-1410 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : Navier-Stokes equations * weak solution * regularity criteria Subject RIV: BA - General Mathematics Impact factor: 1.265, year: 2014 http://epubs.siam.org/doi/abs/10.1137/120874874

Solute–Solute Interaction In α IRON: The Status QUO

Directory of Open Access Journals (Sweden)

Numakura H.

2015-09-01

Full Text Available An overview is presented on the interaction of substitutional solutes with carbon and nitrogen in α iron, which is an important factor in controlling the properties of steels. Starting from a simple model of trapping of the interstitial solute atoms by substitutional solute atoms, the principles of experimental methods for quantitative studies are described, focussing on the Snoek relaxation and solubility measurements, and the knowledge acquired by such experiments is reviewed. An account of recent theoretical approaches to the interaction is also given.

Determine point-to-point networking interactions using regular expressions

Directory of Open Access Journals (Sweden)

Konstantin S. Deev

2015-06-01

Full Text Available As Internet growth and becoming more popular, the number of concurrent data flows start to increasing, which makes sense in bandwidth requested. Providers and corporate customers need ability to identify point-to-point interactions. The best is to use special software and hardware implementations that distribute the load in the internals of the complex, using the principles and approaches, in particular, described in this paper. This paper represent the principles of building system, which searches for a regular expression match using computing on graphics adapter in server station. A significant computing power and capability to parallel execution on modern graphic processor allows inspection of large amounts of data through sets of rules. Using the specified characteristics can lead to increased computing power in 30…40 times compared to the same setups on the central processing unit. The potential increase in bandwidth capacity could be used in systems that provide packet analysis, firewalls and network anomaly detectors.

Bulk viscosity, interaction and the viability of phantom solutions

Energy Technology Data Exchange (ETDEWEB)

Leyva, Yoelsy; Sepulveda, Mirko [Universidad de Tarapaca, Departamento de Fisica, Facultad de Ciencias, Arica (Chile)

2017-06-15

We study the dynamics of a bulk viscosity model in the Eckart approach for a spatially flat Friedmann-Robertson-Walker (FRW) Universe. We have included radiation and dark energy, assumed as perfect fluids, and dark matter treated as an imperfect fluid having bulk viscosity. We also introduce an interaction term between the dark matter and dark energy components. Considering that the bulk viscosity is proportional to the dark matter energy density and imposing a complete cosmological dynamics, we find bounds on the bulk viscosity in order to reproduce a matter-dominated era (MDE). This constraint is independent of the interaction term. Some late time phantom solutions are mathematically possible. However, the constraint imposed by a MDE restricts the interaction parameter, in the phantom solutions, to a region consistent with a null value, eliminating the possibility of late time stable solutions with w < -1. From the different cases that we study, the only possible scenario, with bulk viscosity and interaction term, belongs to the quintessence region. In the latter case, we find bounds on the interaction parameter compatible with latest observational data. (orig.)

On condensation driven by electrostatic interactions in macroionic solutions

International Nuclear Information System (INIS)

Badirkhan, Z.; Tosi, M.P.

1989-04-01

Liquid-vapour phase separation, as it normally follows from attractive interactions, is demonstrated under pure Coulomb interactions for the primitive model of macroionic solutions in the mean spherical approximation and related to observations on dilute solutions of highly charged latex particles. It is stressed that the corresponding effective pair potential between macro-ions is of the DLVO repulsive type. (author). 14 refs, 2 figs

Solvent - solute interaction

International Nuclear Information System (INIS)

Urbanczyk, A.; Kalinowski, M.K.

1983-01-01

The electronic absorption spectrum of vanadyl acetylacetonate has been studied in 15 organic solvents. It has been found that wavenumbers and molar absorptivities of the long-wavelength bands (d-d transitions) can be well described by a complementary Lewis acid-base model including Gutmann's donor number [Gutmann V., Wychera E., Inorg. Nucl. Chem. Letters 2, 257 (1966)] and acceptor number [Mayer U., Gutmann V., Gerger W., Monatsh. Chem. 106, 1235 (1975)] of a solvent. This model describes also the solvent effect of the hyperfine splitting constant, Asub(iso)( 51 V), from e.s.r. spectra of VOacac 2 . These observations are discussed in terms of the donor-acceptor concept for solvent-solute interactions. (Author)

Evidence for the Modulation of Sub-Lexical Processing in Go No-Go Naming: The Elimination of the Frequency x Regularity Interaction

Science.gov (United States)

Cummine, Jacqueline; Amyotte, Josee; Pancheshen, Brent; Chouinard, Brea

2011-01-01

The Frequency (high vs. low) x Regularity (regular vs. exception) interaction found on naming response times is often taken as evidence for parallel processing of sub-lexical and lexical systems. Using a Go/No-go naming task, we investigated the effect of nonword versus pseudohomophone foils on sub-lexical processing and the subsequent Frequency x…

Regularized Fractional Power Parameters for Image Denoising Based on Convex Solution of Fractional Heat Equation

Directory of Open Access Journals (Sweden)

Hamid A. Jalab

2014-01-01

Full Text Available The interest in using fractional mask operators based on fractional calculus operators has grown for image denoising. Denoising is one of the most fundamental image restoration problems in computer vision and image processing. This paper proposes an image denoising algorithm based on convex solution of fractional heat equation with regularized fractional power parameters. The performances of the proposed algorithms were evaluated by computing the PSNR, using different types of images. Experiments according to visual perception and the peak signal to noise ratio values show that the improvements in the denoising process are competent with the standard Gaussian filter and Wiener filter.

Charge generation layers for solution processed tandem organic light emitting diodes with regular device architecture.

Science.gov (United States)

Höfle, Stefan; Bernhard, Christoph; Bruns, Michael; Kübel, Christian; Scherer, Torsten; Lemmer, Uli; Colsmann, Alexander

2015-04-22

Tandem organic light emitting diodes (OLEDs) utilizing fluorescent polymers in both sub-OLEDs and a regular device architecture were fabricated from solution, and their structure and performance characterized. The charge carrier generation layer comprised a zinc oxide layer, modified by a polyethylenimine interface dipole, for electron injection and either MoO3, WO3, or VOx for hole injection into the adjacent sub-OLEDs. ToF-SIMS investigations and STEM-EDX mapping verified the distinct functional layers throughout the layer stack. At a given device current density, the current efficiencies of both sub-OLEDs add up to a maximum of 25 cd/A, indicating a properly working tandem OLED.

Regularized Regression and Density Estimation based on Optimal Transport

KAUST Repository

Burger, M.

2012-03-11

The aim of this paper is to investigate a novel nonparametric approach for estimating and smoothing density functions as well as probability densities from discrete samples based on a variational regularization method with the Wasserstein metric as a data fidelity. The approach allows a unified treatment of discrete and continuous probability measures and is hence attractive for various tasks. In particular, the variational model for special regularization functionals yields a natural method for estimating densities and for preserving edges in the case of total variation regularization. In order to compute solutions of the variational problems, a regularized optimal transport problem needs to be solved, for which we discuss several formulations and provide a detailed analysis. Moreover, we compute special self-similar solutions for standard regularization functionals and we discuss several computational approaches and results. © 2012 The Author(s).

Regularities of thermochemical characteristics of 1-1, 2-1, 3-1 electrolyte solutions in dimethyl sulfoxide-water and propylene carbonate water mixtures

International Nuclear Information System (INIS)

Vorob'ev, A.F.; Monaenkova, A.S.; AlekseeV, G.I.

1987-01-01

In an air-tight tilting calorimeter with an isothermal casing enthalpies of praseodymium chloride solution in water, dimethyl sulfoxide (DMSO) - water mixtures, contaning 3.86 and 18.53 mol.% DMSO, and propylene carbonate (PC) - water mixtures, containing 1.85 and 3.23 mol.% PC are measured. The enthalpies of praseodymium chloride solution in the given mixtures in case of infinite solution dilution are determined. Solvation enthalpies of praseodymium and neodymium chlorides, as well as alkali earth metal and magnesium chlorides in water and DMSO - water and PC - water mixtures are calculated. Regularities in thermochemical characteristics of solutions of the given salts in DMSO - water and PC - water mixtures are discussed

Regularized Regression and Density Estimation based on Optimal Transport

KAUST Repository

Burger, M.; Franek, M.; Schonlieb, C.-B.

2012-01-01

for estimating densities and for preserving edges in the case of total variation regularization. In order to compute solutions of the variational problems, a regularized optimal transport problem needs to be solved, for which we discuss several formulations

Dynamical interactions between solute and solvent studied by nonlinear infrared spectroscopy

International Nuclear Information System (INIS)

Ohta, K.; Tominaga, K.

2006-01-01

Interactions between solute and solvent play an important role in chemical reaction dynamics and in many relaxation processes in condensed phases. Recently third-order nonlinear infrared (IR) spectroscopy has shown to be useful to investigate solute-solvent interaction and dynamics of the vibrational transition. These studies provide detailed information on the energy relaxation of the vibrationally excited state, and the time scale and the magnitude of the time correlation functions of the vibrational frequency fluctuations. In this work we have studied vibrational energy relaxation (VER) of solutions and molecular complexes by nonlinear IR spectroscopy, especially IR pump-probe method, to understand the microscopic interactions in liquids. (authors)

Nonautonomous discrete bright soliton solutions and interaction management for the Ablowitz-Ladik equation.

Science.gov (United States)

Yu, Fajun

2015-03-01

We present the nonautonomous discrete bright soliton solutions and their interactions in the discrete Ablowitz-Ladik (DAL) equation with variable coefficients, which possesses complicated wave propagation in time and differs from the usual bright soliton waves. The differential-difference similarity transformation allows us to relate the discrete bright soliton solutions of the inhomogeneous DAL equation to the solutions of the homogeneous DAL equation. Propagation and interaction behaviors of the nonautonomous discrete solitons are analyzed through the one- and two-soliton solutions. We study the discrete snaking behaviors, parabolic behaviors, and interaction behaviors of the discrete solitons. In addition, the interaction management with free functions and dynamic behaviors of these solutions is investigated analytically, which have certain applications in electrical and optical systems.

Ions in solution basic principles of chemical interactions

CERN Document Server

Burgess, J

1999-01-01

This outline of the principles and chemical interactions in inorganic solution chemistry delivers a course module in an area of considerable complexity. Problems with solutions and tutorial hints to test comprehension have been added as a feature to check readers' understanding and assist self-study. Exercises and projects are also provided to help readers deepen and extend their knowledge and understanding. Inorganic solution chemistry is treated thoroughly Emphasis is placed upon NMR, UV-VIS, IR Raman spectroscopy, X-ray diffraction, and such topics as acid-base behaviour, stability constants and kinetics.

Further investigation on "A multiplicative regularization for force reconstruction"

Science.gov (United States)

Aucejo, M.; De Smet, O.

2018-05-01

We have recently proposed a multiplicative regularization to reconstruct mechanical forces acting on a structure from vibration measurements. This method does not require any selection procedure for choosing the regularization parameter, since the amount of regularization is automatically adjusted throughout an iterative resolution process. The proposed iterative algorithm has been developed with performance and efficiency in mind, but it is actually a simplified version of a full iterative procedure not described in the original paper. The present paper aims at introducing the full resolution algorithm and comparing it with its simplified version in terms of computational efficiency and solution accuracy. In particular, it is shown that both algorithms lead to very similar identified solutions.

Regularity of the Maxwell equations in heterogeneous media and Lipschitz domains

KAUST Repository

Bonito, Andrea

2013-12-01

This note establishes regularity estimates for the solution of the Maxwell equations in Lipschitz domains with non-smooth coefficients and minimal regularity assumptions. The argumentation relies on elliptic regularity estimates for the Poisson problem with non-smooth coefficients. © 2013 Elsevier Ltd.

Traveling waves of the regularized short pulse equation

International Nuclear Information System (INIS)

Shen, Y; Horikis, T P; Kevrekidis, P G; Frantzeskakis, D J

2014-01-01

The properties of the so-called regularized short pulse equation (RSPE) are explored with a particular focus on the traveling wave solutions of this model. We theoretically analyze and numerically evolve two sets of such solutions. First, using a fixed point iteration scheme, we numerically integrate the equation to find solitary waves. It is found that these solutions are well approximated by a finite sum of hyperbolic secants powers. The dependence of the soliton's parameters (height, width, etc) to the parameters of the equation is also investigated. Second, by developing a multiple scale reduction of the RSPE to the nonlinear Schrödinger equation, we are able to construct (both standing and traveling) envelope wave breather type solutions of the former, based on the solitary wave structures of the latter. Both the regular and the breathing traveling wave solutions identified are found to be robust and should thus be amenable to observations in the form of few optical cycle pulses. (paper)

A multiresolution method for solving the Poisson equation using high order regularization

DEFF Research Database (Denmark)

Hejlesen, Mads Mølholm; Walther, Jens Honore

2016-01-01

We present a novel high order multiresolution Poisson solver based on regularized Green's function solutions to obtain exact free-space boundary conditions while using fast Fourier transforms for computational efficiency. Multiresolution is a achieved through local refinement patches and regulari......We present a novel high order multiresolution Poisson solver based on regularized Green's function solutions to obtain exact free-space boundary conditions while using fast Fourier transforms for computational efficiency. Multiresolution is a achieved through local refinement patches...... and regularized Green's functions corresponding to the difference in the spatial resolution between the patches. The full solution is obtained utilizing the linearity of the Poisson equation enabling super-position of solutions. We show that the multiresolution Poisson solver produces convergence rates...

A Visualization Technique for Accessing Solution Pool in Interactive Methods of Multiobjective Optimization

OpenAIRE

Filatovas, Ernestas; Podkopaev, Dmitry; Kurasova, Olga

2015-01-01

Interactive methods of multiobjective optimization repetitively derive Pareto optimal solutions based on decision maker’s preference information and present the obtained solutions for his/her consideration. Some interactive methods save the obtained solutions into a solution pool and, at each iteration, allow the decision maker considering any of solutions obtained earlier. This feature contributes to the flexibility of exploring the Pareto optimal set and learning about the op...

Formation factor of regular porous pattern in poly-α-methylstyrene film

International Nuclear Information System (INIS)

Yang Ruizhuang; Xu Jiajing; Gao Cong; Ma Shuang; Chen Sufen; Luo Xuan; Fang Yu; Li Bo

2015-01-01

Regular poly-α-methylstyrene (PAMS) porous film with macron-sized cells was prepared by casting the solution in the condition with high humidity. In this paper, the effects of the molecular weight of PAMS, PAMS concentration, humidity, temperature, volatile solvents and the thickness of liquid of solution on formation of regular porous pattern in PAMS film were discussed. The results show that these factors significantly affect the pore size and the pore distribution. The capillary force and Benard-Marangoni convection are main driving forces for the water droplet moving and making pores regular arrangement. (authors)

Calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid

International Nuclear Information System (INIS)

Kurbanov, A.R.; Sharipov, D.Sh.

1993-01-01

Present article is devoted to calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid. The calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid was carried out in order to determine the thermal effects of reactions. The results of interaction of Ba(OH) 4 ·8H 2 O with 5, 10, and 20% solution of hydrofluoric acid were considered.

Associative Interactions in Crowded Solutions of Biopolymers Counteract Depletion Effects.

Science.gov (United States)

Groen, Joost; Foschepoth, David; te Brinke, Esra; Boersma, Arnold J; Imamura, Hiromi; Rivas, Germán; Heus, Hans A; Huck, Wilhelm T S

2015-10-14

The cytosol of Escherichia coli is an extremely crowded environment, containing high concentrations of biopolymers which occupy 20-30% of the available volume. Such conditions are expected to yield depletion forces, which strongly promote macromolecular complexation. However, crowded macromolecule solutions, like the cytosol, are very prone to nonspecific associative interactions that can potentially counteract depletion. It remains unclear how the cytosol balances these opposing interactions. We used a FRET-based probe to systematically study depletion in vitro in different crowded environments, including a cytosolic mimic, E. coli lysate. We also studied bundle formation of FtsZ protofilaments under identical crowded conditions as a probe for depletion interactions at much larger overlap volumes of the probe molecule. The FRET probe showed a more compact conformation in synthetic crowding agents, suggesting strong depletion interactions. However, depletion was completely negated in cell lysate and other protein crowding agents, where the FRET probe even occupied slightly more volume. In contrast, bundle formation of FtsZ protofilaments proceeded as readily in E. coli lysate and other protein solutions as in synthetic crowding agents. Our experimental results and model suggest that, in crowded biopolymer solutions, associative interactions counterbalance depletion forces for small macromolecules. Furthermore, the net effects of macromolecular crowding will be dependent on both the size of the macromolecule and its associative interactions with the crowded background.

Effects of solute-solute interactions on protein stability studied using various counterions and dendrimers.

Directory of Open Access Journals (Sweden)

Curtiss P Schneider

Full Text Available Much work has been performed on understanding the effects of additives on protein thermodynamics and degradation kinetics, in particular addressing the Hofmeister series and other broad empirical phenomena. Little attention, however, has been paid to the effect of additive-additive interactions on proteins. Our group and others have recently shown that such interactions can actually govern protein events, such as aggregation. Here we use dendrimers, which have the advantage that both size and surface chemical groups can be changed and therein studied independently. Dendrimers are a relatively new and broad class of materials which have been demonstrated useful in biological and therapeutic applications, such as drug delivery, perturbing amyloid formation, etc. Guanidinium modified dendrimers pose an interesting case given that guanidinium can form multiple attractive hydrogen bonds with either a protein surface or other components in solution, such as hydrogen bond accepting counterions. Here we present a study which shows that the behavior of such macromolecule species (modified PAMAM dendrimers is governed by intra-solvent interactions. Attractive guanidinium-anion interactions seem to cause clustering in solution, which inhibits cooperative binding to the protein surface but at the same time, significantly suppresses nonnative aggregation.

Molecular Theory and the Effects of Solute Attractive Forces on Hydrophobic Interactions.

Science.gov (United States)

Chaudhari, Mangesh I; Rempe, Susan B; Asthagiri, D; Tan, L; Pratt, L R

2016-03-03

The role of solute attractive forces on hydrophobic interactions is studied by coordinated development of theory and simulation results for Ar atoms in water. We present a concise derivation of the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions, a derivation that clarifies the close relation of LMF theory to the EXP approximation applied to this problem long ago. The simulation results show that change from purely repulsive atomic solute interactions to include realistic attractive interactions diminishes the strength of hydrophobic bonds. For the Ar-Ar rdfs considered pointwise, the numerical results for the effects of solute attractive forces on hydrophobic interactions are opposite in sign and larger in magnitude than predicted by LMF theory. That comparison is discussed from the point of view of quasichemical theory, and it is suggested that the first reason for this difference is the incomplete evaluation within LMF theory of the hydration energy of the Ar pair. With a recent suggestion for the system-size extrapolation of the required correlation function integrals, the Ar-Ar rdfs permit evaluation of osmotic second virial coefficients B2. Those B2's also show that incorporation of attractive interactions leads to more positive (repulsive) values. With attractive interactions in play, B2 can change from positive to negative values with increasing temperatures. This is consistent with the puzzling suggestions of decades ago that B2 ≈ 0 for intermediate cases of temperature or solute size. In all cases here, B2 becomes more attractive with increasing temperature.

Interaction of tellurium and tellurium-containing semiconductor compounds with solutions of HI-HNO3-H2O system

International Nuclear Information System (INIS)

Tomashik, V.N.; Sava, A.A.; Tomashik, Z.F.

1994-01-01

As a result of experimental investigations and physical-chemical simulation are established regularities of solution of semiconducting tellurium-containing compounds in HI-HNO 3 -H 2 O systems. In HNO 3 -HI system solutions enriched by HNO 3 are not used for CdTe treatment but HI enriched solution are similar in composition with I 2 -HI solutions. Solution of the given tellurium-containing materials proceeds by a chemical mechanism and is determined by tellurium oxidation with iodine

Cosmological solutions in string theory with dilaton self interaction potential

International Nuclear Information System (INIS)

Mora, C.; Pimentel, L.O.

2003-01-01

In this work we present homogeneous and isotropic cosmological solutions for the low energy limit of string theory with a self interacting potential for the scalar field. For a potential that is a linear combination of two exponential, a family of exact solutions are found for the different spatial curvatures. Among this family a non singular accelerating solution for positive curvature is singled out and the violation of the energy conditions for that solution is studied, and also its astrophysical consequences. The string coupling for this solution is finite. (Author)

A projection-based approach to general-form Tikhonov regularization

DEFF Research Database (Denmark)

Kilmer, Misha E.; Hansen, Per Christian; Espanol, Malena I.

2007-01-01

We present a projection-based iterative algorithm for computing general-form Tikhonov regularized solutions to the problem minx| Ax-b |2^2+lambda2| Lx |2^2, where the regularization matrix L is not the identity. Our algorithm is designed for the common case where lambda is not known a priori...

Principles of interactions in non-aqueous electrolyte solutions

NARCIS (Netherlands)

Lyklema, J.

2013-01-01

In this paper a review is presented on the molecular interactions in non-aqueous media of low dielectric permittivity. Qualitative and quantitative distinctions with aqueous solutions are emphasized. The reviewed themes include dispersion forces, dissociation and association equilibria,

UNFOLDED REGULAR AND SEMI-REGULAR POLYHEDRA

Directory of Open Access Journals (Sweden)

IONIŢĂ Elena

2015-06-01

Full Text Available This paper proposes a presentation unfolding regular and semi-regular polyhedra. Regular polyhedra are convex polyhedra whose faces are regular and equal polygons, with the same number of sides, and whose polyhedral angles are also regular and equal. Semi-regular polyhedra are convex polyhedra with regular polygon faces, several types and equal solid angles of the same type. A net of a polyhedron is a collection of edges in the plane which are the unfolded edges of the solid. Modeling and unfolding Platonic and Arhimediene polyhedra will be using 3dsMAX program. This paper is intended as an example of descriptive geometry applications.

Wormhole solutions with a complex ghost scalar field and their instability

Science.gov (United States)

Dzhunushaliev, Vladimir; Folomeev, Vladimir; Kleihaus, Burkhard; Kunz, Jutta

2018-01-01

We study compact configurations with a nontrivial wormholelike spacetime topology supported by a complex ghost scalar field with a quartic self-interaction. For this case, we obtain regular asymptotically flat equilibrium solutions possessing reflection symmetry. We then show their instability with respect to linear radial perturbations.

Approximate Solutions of Interactive Dynamic Influence Diagrams Using Model Clustering

DEFF Research Database (Denmark)

Zeng, Yifeng; Doshi, Prashant; Qiongyu, Cheng

2007-01-01

Interactive dynamic influence diagrams (I-DIDs) offer a transparent and semantically clear representation for the sequential decision-making problem over multiple time steps in the presence of other interacting agents. Solving I-DIDs exactly involves knowing the solutions of possible models...

Influence of hydroxypropylmethyl cellulose-sodium laurylsulfate interaction on rheological properties of the solution

Directory of Open Access Journals (Sweden)

Šaletić Jelena V.

2004-01-01

Full Text Available Interactions between the polymers and surfactants in solution have widely been investigated because of their scientific and technological importance. These interactions can be utilized to modify the physicochemical properties of system in many food products, pharmaceutical formulations, personal care products, paints, pesticides, etc. Interaction between nonionic polymer - hydroxypropylmethyl cellulose (HPMC and anionic surfactant - sodium laurylsulfate (SDS in solution has been investigated in this paper by rheological measurements. Rheological measurements are performed by rotational viscometer at 20°C and changes of rheological characteristics of HPMC solutions (0.5-1.5% with increasing SDS concentrations (0-4.0% were determined. The results of these investigations showed that viscosity of the solution is dependant on HPMC-SDS interaction. At particular SDS concentration viscosity increases, reach maximum and after that decreases until reach constant value. From the viscosity changes the characteristic concentrations of SDS, critical aggregation concentration (cac and polymer saturation point (psp, were determined. These concentrations are in linear relationships with HPMC concentrations. Rheological properties of the solution are strong influenced by HPMC-SDS interaction and exhibits more or less pronounced pseudoplastic behavior, which changes to Newtonian one after the psp has been reached.

Bardeen regular black hole with an electric source

Science.gov (United States)

Rodrigues, Manuel E.; Silva, Marcos V. de S.

2018-06-01

If some energy conditions on the stress-energy tensor are violated, is possible construct regular black holes in General Relativity and in alternative theories of gravity. This type of solution has horizons but does not present singularities. The first regular black hole was presented by Bardeen and can be obtained from Einstein equations in the presence of an electromagnetic field. E. Ayon-Beato and A. Garcia reinterpreted the Bardeen metric as a magnetic solution of General Relativity coupled to a nonlinear electrodynamics. In this work, we show that the Bardeen model may also be interpreted as a solution of Einstein equations in the presence of an electric source, whose electric field does not behave as a Coulomb field. We analyzed the asymptotic forms of the Lagrangian for the electric case and also analyzed the energy conditions.

New applications of Boson's coherent states of double modes at regular product

International Nuclear Information System (INIS)

Zhang Yongde; Ren Yong

1987-05-01

This paper presents a series of new applications of boson's coherent states of double modes by means of the technique of regular products. They include non-coupled double oscillator solutions at two time dependent extra-sources; coupled double oscillator solutions at two time dependent extra-sources; some applications to regular momentum theory; an explicit expression for time-reversal operator. (author). 7 refs

Enthalpic characteristics of interactions occurring between an ascorbic acid and some saccharides in aqueous solutions

International Nuclear Information System (INIS)

Terekhova, Irina V.; Kulikov, Oleg V.; Titova, Elena S.

2004-01-01

The enthalpies of solution of mono- and disaccharides were measured in water and aqueous ascorbic acid solutions at 298.15 K using a calorimeter of solution. Enthalpies of transfer of saccharides from water to aqueous ascorbic acid solutions were derived, and enthalpic coefficients of pair interaction h xy were calculated according to MacMillan-Mayer theory. Interactions of ascorbic acid with D-fructose and sucrose are energetically favorable and characterized by negative h xy coefficients while h xy for the interactions occurring between ascorbic acid and α-D glucose, D-galactose and maltose are positive. The obtained results are interpreted in terms of the influence of structure and solvation of solutes on the thermodynamic parameters of their interaction in solutions

Late time solution for interacting scalar in accelerating spaces

Energy Technology Data Exchange (ETDEWEB)

Prokopec, Tomislav, E-mail: t.prokopec@uu.nl [Institute for Theoretical Physics, Spinoza Institute and EMME$\\Phi$, Utrecht University, Postbus 80.195, Utrecht, 3508 TD The Netherlands (Netherlands)

2015-11-01

We consider stochastic inflation in an interacting scalar field in spatially homogeneous accelerating space-times with a constant principal slow roll parameter ε. We show that, if the scalar potential is scale invariant (which is the case when scalar contains quartic self-interaction and couples non-minimally to gravity), the late-time solution on accelerating FLRW spaces can be described by a probability distribution function (PDF) ρ which is a function of φ/H only, where φ=φ( x-vector ) is the scalar field and H=H(t) denotes the Hubble parameter. We give explicit late-time solutions for ρarrow ρ{sub ∞}(φ/H), and thereby find the order ε corrections to the Starobinsky-Yokoyama result. This PDF can then be used to calculate e.g. various n-point functions of the (self-interacting) scalar field, which are valid at late times in arbitrary accelerating space-times with ε= constant.

Analytic Solutions and Resonant Solutions of Hyperbolic Partial Differential Equations

Science.gov (United States)

Wagenmaker, Timothy Roger

This dissertation contains two main subject areas. The first deals with solutions to the wave equation Du/Dt + a Du/Dx = 0, where D/Dt and D/Dx represent partial derivatives and a(t,x) is real valued. The question I studied, which arises in control theory, is whether solutions which are real analytic with respect to the time variable are dense in the space of all solutions. If a is real analytic in t and x, the Cauchy-Kovalevsky Theorem implies that the solutions real analytic in t and x are dense, since it suffices to approximate the initial data by polynomials. The same positive result is valid when a is continuously differentiable and independent of t. This is proved by regularization in time. The hypothesis that a is independent of t cannot be replaced by the weaker assumption that a is real analytic in t, even when it is infinitely smooth. I construct a(t,x) for which the solutions which are analytic in time are automatically periodic in time. In particular these solutions are not dense in the space of all solutions. The second area concerns the resonant interaction of oscillatory waves propagating in a compressible inviscid fluid. An asymptotic description given by Andrew Majda, Rodolfo Rosales, and Maria Schonbek (MRS) involves the genuinely nonlinear quasilinear hyperbolic system Du/Dt + D(uu/2)/Dt + v = 0, Dv/Dt - D(vv/2)/Dt - u = 0. They performed many numerical simulations which indicated that small amplitude solutions of this system tend to evade shock formation, and conjectured that "smooth initial data with a sufficiently small amplitude never develop shocks throughout a long time interval of integration.". I proved that for smooth periodic U(x), V(x) and initial data u(0,x) = epsilonU(x), v(0,x) = epsilonV(x), the solution is smooth for time at least constant times | ln epsilon| /epsilon. This is longer than the lifetime order 1/ epsilon of the solution to the decoupled Burgers equations. The decoupled equation describes nonresonant interaction of

Low-rank matrix approximation with manifold regularization.

Science.gov (United States)

Zhang, Zhenyue; Zhao, Keke

2013-07-01

This paper proposes a new model of low-rank matrix factorization that incorporates manifold regularization to the matrix factorization. Superior to the graph-regularized nonnegative matrix factorization, this new regularization model has globally optimal and closed-form solutions. A direct algorithm (for data with small number of points) and an alternate iterative algorithm with inexact inner iteration (for large scale data) are proposed to solve the new model. A convergence analysis establishes the global convergence of the iterative algorithm. The efficiency and precision of the algorithm are demonstrated numerically through applications to six real-world datasets on clustering and classification. Performance comparison with existing algorithms shows the effectiveness of the proposed method for low-rank factorization in general.

PET regularization by envelope guided conjugate gradients

International Nuclear Information System (INIS)

Kaufman, L.; Neumaier, A.

1996-01-01

The authors propose a new way to iteratively solve large scale ill-posed problems and in particular the image reconstruction problem in positron emission tomography by exploiting the relation between Tikhonov regularization and multiobjective optimization to obtain iteratively approximations to the Tikhonov L-curve and its corner. Monitoring the change of the approximate L-curves allows us to adjust the regularization parameter adaptively during a preconditioned conjugate gradient iteration, so that the desired solution can be reconstructed with a small number of iterations

Regularized variable metric method versus the conjugate gradient method in solution of radiative boundary design problem

International Nuclear Information System (INIS)

Kowsary, F.; Pooladvand, K.; Pourshaghaghy, A.

2007-01-01

In this paper, an appropriate distribution of the heating elements' strengths in a radiation furnace is estimated using inverse methods so that a pre-specified temperature and heat flux distribution is attained on the design surface. Minimization of the sum of the squares of the error function is performed using the variable metric method (VMM), and the results are compared with those obtained by the conjugate gradient method (CGM) established previously in the literature. It is shown via test cases and a well-founded validation procedure that the VMM, when using a 'regularized' estimator, is more accurate and is able to reach at a higher quality final solution as compared to the CGM. The test cases used in this study were two-dimensional furnaces filled with an absorbing, emitting, and scattering gas

A Quantum Dot with Spin-Orbit Interaction--Analytical Solution

Science.gov (United States)

Basu, B.; Roy, B.

2009-01-01

The practical applicability of a semiconductor quantum dot with spin-orbit interaction gives an impetus to study analytical solutions to one- and two-electron quantum dots with or without a magnetic field.

Energy functions for regularization algorithms

Science.gov (United States)

Delingette, H.; Hebert, M.; Ikeuchi, K.

1991-01-01

Regularization techniques are widely used for inverse problem solving in computer vision such as surface reconstruction, edge detection, or optical flow estimation. Energy functions used for regularization algorithms measure how smooth a curve or surface is, and to render acceptable solutions these energies must verify certain properties such as invariance with Euclidean transformations or invariance with parameterization. The notion of smoothness energy is extended here to the notion of a differential stabilizer, and it is shown that to void the systematic underestimation of undercurvature for planar curve fitting, it is necessary that circles be the curves of maximum smoothness. A set of stabilizers is proposed that meet this condition as well as invariance with rotation and parameterization.

Zeroth order regular approximation approach to electric dipole moment interactions of the electron

Science.gov (United States)

Gaul, Konstantin; Berger, Robert

2017-07-01

A quasi-relativistic two-component approach for an efficient calculation of P ,T -odd interactions caused by a permanent electric dipole moment of the electron (eEDM) is presented. The approach uses a (two-component) complex generalized Hartree-Fock and a complex generalized Kohn-Sham scheme within the zeroth order regular approximation. In applications to select heavy-elemental polar diatomic molecular radicals, which are promising candidates for an eEDM experiment, the method is compared to relativistic four-component electron-correlation calculations and confirms values for the effective electric field acting on the unpaired electron for RaF, BaF, YbF, and HgF. The calculations show that purely relativistic effects, involving only the lower component of the Dirac bi-spinor, are well described by treating only the upper component explicitly.

Spectral Regularization Algorithms for Learning Large Incomplete Matrices.

Science.gov (United States)

Mazumder, Rahul; Hastie, Trevor; Tibshirani, Robert

2010-03-01

We use convex relaxation techniques to provide a sequence of regularized low-rank solutions for large-scale matrix completion problems. Using the nuclear norm as a regularizer, we provide a simple and very efficient convex algorithm for minimizing the reconstruction error subject to a bound on the nuclear norm. Our algorithm Soft-Impute iteratively replaces the missing elements with those obtained from a soft-thresholded SVD. With warm starts this allows us to efficiently compute an entire regularization path of solutions on a grid of values of the regularization parameter. The computationally intensive part of our algorithm is in computing a low-rank SVD of a dense matrix. Exploiting the problem structure, we show that the task can be performed with a complexity linear in the matrix dimensions. Our semidefinite-programming algorithm is readily scalable to large matrices: for example it can obtain a rank-80 approximation of a 10(6) × 10(6) incomplete matrix with 10(5) observed entries in 2.5 hours, and can fit a rank 40 approximation to the full Netflix training set in 6.6 hours. Our methods show very good performance both in training and test error when compared to other competitive state-of-the art techniques.

Regularizing properties of Complex Monge-Amp\\`ere flows

OpenAIRE

Tô, Tat Dat

2016-01-01

We study the regularizing properties of complex Monge-Amp\\`ere flows on a K\\"ahler manifold $(X,\\omega)$ when the initial data are $\\omega$-psh functions with zero Lelong number at all points. We prove that the general Monge-Amp\\`ere flow has a solution which is immediately smooth. We also prove the uniqueness and stability of solution.

A Mesoscopic Model for Protein-Protein Interactions in Solution

OpenAIRE

Lund, Mikael; Jönsson, Bo

2003-01-01

Protein self-association may be detrimental in biological systems, but can be utilized in a controlled fashion for protein crystallization. It is hence of considerable interest to understand how factors like solution conditions prevent or promote aggregation. Here we present a computational model describing interactions between protein molecules in solution. The calculations are based on a molecular description capturing the detailed structure of the protein molecule using x-ray or nuclear ma...

Regularity of solutions of a phase field model

KAUST Repository

Amler, Thomas

2013-01-01

Phase field models are widely-used for modelling phase transition processes such as solidification, freezing or CO2 sequestration. In this paper, a phase field model proposed by G. Caginalp is considered. The existence and uniqueness of solutions are proved in the case of nonsmooth initial data. Continuity of solutions with respect to time is established. In particular, it is shown that the governing initial boundary value problem can be considered as a dynamical system. © 2013 International Press.

Thermodynamics of hydrogen bonding and van der Waals interactions of organic solutes in solutions of imidazolium based ionic liquids: “Structure-property” relationships

International Nuclear Information System (INIS)

Varfolomeev, Mikhail A.; Khachatrian, Artashes A.; Akhmadeev, Bulat S.; Solomonov, Boris N.

2016-01-01

Highlights: • Solution enthalpies of organic solutes in imidazolium based ionic liquids were measured. • van der Waals interactions scale of imidazolium based ionic liquids was proposed. • Enthalpies of solvation of organic solutes in ionic liquids were determined. • Hydrogen bond enthalpies of organic solutes with ionic liquids were calculated. • Relationships between structure of ionic liquids and thermochemical data were obtained. - Abstract: In the present work thermochemistry of intermolecular interactions of organic compounds in solutions of imidazolium based ionic liquids (ILs) has been studied using solution calorimetry method. Enthalpies of solution at infinite dilution of non-polar (alkanes, aromatic hydrocarbons) and polar (alcohols, amides, and etc.) organic solutes in two ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate were measured at 298.15 K. The scale of van der Waals interactions of imidazolium based ILs has been proposed on the basis of solution enthalpies of n-alkanes in their media. The effect of the cation and anion structure of ILs on the enthalpies of solvation was analyzed. Enthalpies of hydrogen bonding of organic solutes with imidazolium based ILs were determined. It has been shown that these values are close to zero for proton acceptor solutes. At the same time, enthalpies of hydrogen bonding of proton donor solutes with ionic liquids are increased depending the anion: tetrafluoroborate ≈ bis(trifluoromethylsulfonyl)imide < 2-(2-methoxyethoxy)ethyl sulfate < trifluoromethanesulfonate. Enthalpies of van der Waals interactions and hydrogen bonding in the solutions of imidazolium based ionic liquids were compared with the same data for molecular solvents.

Thermodynamics of hydrogen bonding and van der Waals interactions of organic solutes in solutions of imidazolium based ionic liquids: “Structure-property” relationships

Energy Technology Data Exchange (ETDEWEB)

Varfolomeev, Mikhail A., E-mail: vma.ksu@gmail.com; Khachatrian, Artashes A.; Akhmadeev, Bulat S.; Solomonov, Boris N.

2016-06-10

Highlights: • Solution enthalpies of organic solutes in imidazolium based ionic liquids were measured. • van der Waals interactions scale of imidazolium based ionic liquids was proposed. • Enthalpies of solvation of organic solutes in ionic liquids were determined. • Hydrogen bond enthalpies of organic solutes with ionic liquids were calculated. • Relationships between structure of ionic liquids and thermochemical data were obtained. - Abstract: In the present work thermochemistry of intermolecular interactions of organic compounds in solutions of imidazolium based ionic liquids (ILs) has been studied using solution calorimetry method. Enthalpies of solution at infinite dilution of non-polar (alkanes, aromatic hydrocarbons) and polar (alcohols, amides, and etc.) organic solutes in two ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate were measured at 298.15 K. The scale of van der Waals interactions of imidazolium based ILs has been proposed on the basis of solution enthalpies of n-alkanes in their media. The effect of the cation and anion structure of ILs on the enthalpies of solvation was analyzed. Enthalpies of hydrogen bonding of organic solutes with imidazolium based ILs were determined. It has been shown that these values are close to zero for proton acceptor solutes. At the same time, enthalpies of hydrogen bonding of proton donor solutes with ionic liquids are increased depending the anion: tetrafluoroborate ≈ bis(trifluoromethylsulfonyl)imide < 2-(2-methoxyethoxy)ethyl sulfate < trifluoromethanesulfonate. Enthalpies of van der Waals interactions and hydrogen bonding in the solutions of imidazolium based ionic liquids were compared with the same data for molecular solvents.

Regularization and computational methods for precise solution of perturbed orbit transfer problems

Science.gov (United States)

Woollands, Robyn Michele

The author has developed a suite of algorithms for solving the perturbed Lambert's problem in celestial mechanics. These algorithms have been implemented as a parallel computation tool that has broad applicability. This tool is composed of four component algorithms and each provides unique benefits for solving a particular type of orbit transfer problem. The first one utilizes a Keplerian solver (a-iteration) for solving the unperturbed Lambert's problem. This algorithm not only provides a "warm start" for solving the perturbed problem but is also used to identify which of several perturbed solvers is best suited for the job. The second algorithm solves the perturbed Lambert's problem using a variant of the modified Chebyshev-Picard iteration initial value solver that solves two-point boundary value problems. This method converges over about one third of an orbit and does not require a Newton-type shooting method and thus no state transition matrix needs to be computed. The third algorithm makes use of regularization of the differential equations through the Kustaanheimo-Stiefel transformation and extends the domain of convergence over which the modified Chebyshev-Picard iteration two-point boundary value solver will converge, from about one third of an orbit to almost a full orbit. This algorithm also does not require a Newton-type shooting method. The fourth algorithm uses the method of particular solutions and the modified Chebyshev-Picard iteration initial value solver to solve the perturbed two-impulse Lambert problem over multiple revolutions. The method of particular solutions is a shooting method but differs from the Newton-type shooting methods in that it does not require integration of the state transition matrix. The mathematical developments that underlie these four algorithms are derived in the chapters of this dissertation. For each of the algorithms, some orbit transfer test cases are included to provide insight on accuracy and efficiency of these

Interactions between halloysite nanotubes and poly(styrene sulfonate) in solution

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Heon; Ryu, Jung Ju; Shin, Joo Huei; Lee, Hoik; Sohn, Dae Won [Dept. of Chemistry and Research Institute for Convergence of Basic Science, Hanyang University, Seoul (Korea, Republic of); Kim, Ick Soo [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, Nagano (Japan)

2017-01-15

The interaction between halloysite nanotubes (HNT) and poly(styrene sulfonate) (PSS) in aqueous solution was investigated by dynamic light scattering. Dynamic behavior of HNT/PSS was observed with different salt, HNT, and PSS concentrations. The HNT colloids were stabilized by PSS over a wide range of HNT concentrations, and HNT suspension in dilute solution formed stable HNT/PSS particles. On the other hand, HNT particles aggregated as sediments at higher concentrations due to strong attraction among HNT rods, and HNT aggregates were stabilized by additional PSS. The interactions between HNT and PSS are described by the van der Waals–London force (VDWL). The stabilization process of HNT/PSS particles in salt solution was proposed by comparing the hydrodynamic radii and apparent intensities of samples. The results demonstrate that electrostatic, steric, and depletion stabilization processes are responsible for the stable dispersion of HNT even at high concentration.

Decentralized formation of random regular graphs for robust multi-agent networks

KAUST Repository

Yazicioglu, A. Yasin

2014-12-15

Multi-agent networks are often modeled via interaction graphs, where the nodes represent the agents and the edges denote direct interactions between the corresponding agents. Interaction graphs have significant impact on the robustness of networked systems. One family of robust graphs is the random regular graphs. In this paper, we present a locally applicable reconfiguration scheme to build random regular graphs through self-organization. For any connected initial graph, the proposed scheme maintains connectivity and the average degree while minimizing the degree differences and randomizing the links. As such, if the average degree of the initial graph is an integer, then connected regular graphs are realized uniformly at random as time goes to infinity.

Massive bosons interacting with gravity: No standard solutions in Robertson-Walker space-time

International Nuclear Information System (INIS)

Zecca, A.

2009-01-01

The problem of the interaction of boson and gravitational field is formulated in the Robertson-Walker space-time. It consist the simultaneous solution of the boson and of the Einstein field equation whose source is the energy momentum tensor of the boson field. By direct verification it is shown that the problem does not admit solutions in the class of massive standard solutions, previously determined, of the boson field equation. Also there cannot be solutions, in case of massive interacting boson, that are superpositions of standard solutions. The case of massless boson field is left open. The result is essentially due to the very special form of the Einstein tensor in Robertson-Walker metric.

STABLE STATIONARY STATES OF NON-LOCAL INTERACTION EQUATIONS

KAUST Repository

FELLNER, KLEMENS

2010-12-01

In this paper, we are interested in the large-time behaviour of a solution to a non-local interaction equation, where a density of particles/individuals evolves subject to an interaction potential and an external potential. It is known that for regular interaction potentials, stable stationary states of these equations are generically finite sums of Dirac masses. For a finite sum of Dirac masses, we give (i) a condition to be a stationary state, (ii) two necessary conditions of linear stability w.r.t. shifts and reallocations of individual Dirac masses, and (iii) show that these linear stability conditions imply local non-linear stability. Finally, we show that for regular repulsive interaction potential Wε converging to a singular repulsive interaction potential W, the Dirac-type stationary states ρ̄ ε approximate weakly a unique stationary state ρ̄ ∈ L∞. We illustrate our results with numerical examples. © 2010 World Scientific Publishing Company.

Regularization and error estimates for nonhomogeneous backward heat problems

Directory of Open Access Journals (Sweden)

Duc Trong Dang

2006-01-01

Full Text Available In this article, we study the inverse time problem for the non-homogeneous heat equation which is a severely ill-posed problem. We regularize this problem using the quasi-reversibility method and then obtain error estimates on the approximate solutions. Solutions are calculated by the contraction principle and shown in numerical experiments. We obtain also rates of convergence to the exact solution.

Regularity of solutions in semilinear elliptic theory

KAUST Repository

Indrei, Emanuel

2016-07-08

We study the semilinear Poisson equation Δu=f(x,u)inB1. (1) Our main results provide conditions on f which ensure that weak solutions of (1) belong to C1,1(B1/2). In some configurations, the conditions are sharp.

Regularized friction and continuation: Comparison with Coulomb's law

OpenAIRE

Vigué, Pierre; Vergez, Christophe; Karkar, Sami; Cochelin, Bruno

2016-01-01

International audience; Periodic solutions of systems with friction are difficult to investigate because of the irregular nature of friction laws. This paper examines periodic solutions and most notably stick-slip, on a simple one-degre-of-freedom system (mass, spring, damper, belt), with Coulomb's friction law, and with a regularized friction law (i.e. the friction coefficient becomes a function of relative speed, with a stiffness parameter). With Coulomb's law, the stick-slip solution is co...

Hairy black hole solutions in U(1) gauge-invariant scalar-vector-tensor theories

Science.gov (United States)

Heisenberg, Lavinia; Tsujikawa, Shinji

2018-05-01

In U (1) gauge-invariant scalar-vector-tensor theories with second-order equations of motion, we study the properties of black holes (BH) on a static and spherically symmetric background. In shift-symmetric theories invariant under the shift of scalar ϕ → ϕ + c, we show the existence of new hairy BH solutions where a cubic-order scalar-vector interaction gives rise to a scalar hair manifesting itself around the event horizon. In the presence of a quartic-order interaction besides the cubic coupling, there are also regular BH solutions endowed with scalar and vector hairs.

Comparing the Reliability of Regular Topologies on a Backbone Network. A Case Study

DEFF Research Database (Denmark)

Cecilio, Sergio Labeage; Gutierrez Lopez, Jose Manuel; Riaz, M. Tahir

2009-01-01

The aim of this paper is to compare the reliability of regular topologies on a backbone network. The study is focused on a large-scale fiberoptic network. Different regular topological solutions as single ring, double ring or 4-Regular grid are applied to the case study, and compared in terms...

Stationary solutions of the Maxwell-Dirac and the Klein-Gordon-Dirac equations

International Nuclear Information System (INIS)

Esteban, M.J.; Georgiev, V.; Sere, E.

1995-01-01

The Maxwell-Dirac system describes the interaction of an electron with its own electromagnetic field. We prove the existence of soliton-like solutions of Maxwell-Dirac in (3+1)-Minkowski space-time. The solutions obtained are regular, stationary in time, and localized in space. They are found by a variational method, as critical points of an energy functional. This functional is strongly indefinite and presents a lack of compactness. We also find soliton-like solutions for the Klein-Gordon-Dirac system, arising in the Yukawa model. (author). 32 refs

Hydrophobic interactions between polymethacrylic acid and sodium laureth sulfate in aqueous solutions

Science.gov (United States)

Yaremko, Z. M.; Fedushinskaya, L. B.; Burka, O. A.; Soltys, M. N.

2014-09-01

The role of hydrophobic interaction in the development of associative processes is demonstrated, based on the concentration dependences of the viscosity and pH of binary solutions of polymethacrylic acid as an anionic polyelectrolyte and sodium laureth sulfate as an anionic surfactant. It is found that the inflection point on the dependence of the difference between the pH values of binary solutions of polymethacrylic acid and sodium laureth sulfate on the polyelectrolyte concentration is a criterion for determining the predominant contribution from hydrophobic interaction, as is the inflection point on the dependence of pH of individual solutions of polymethacrylic acid on the polyelectrolyte concentration.

Higher order total variation regularization for EIT reconstruction.

Science.gov (United States)

Gong, Bo; Schullcke, Benjamin; Krueger-Ziolek, Sabine; Zhang, Fan; Mueller-Lisse, Ullrich; Moeller, Knut

2018-01-08

Electrical impedance tomography (EIT) attempts to reveal the conductivity distribution of a domain based on the electrical boundary condition. This is an ill-posed inverse problem; its solution is very unstable. Total variation (TV) regularization is one of the techniques commonly employed to stabilize reconstructions. However, it is well known that TV regularization induces staircase effects, which are not realistic in clinical applications. To reduce such artifacts, modified TV regularization terms considering a higher order differential operator were developed in several previous studies. One of them is called total generalized variation (TGV) regularization. TGV regularization has been successively applied in image processing in a regular grid context. In this study, we adapted TGV regularization to the finite element model (FEM) framework for EIT reconstruction. Reconstructions using simulation and clinical data were performed. First results indicate that, in comparison to TV regularization, TGV regularization promotes more realistic images. Graphical abstract Reconstructed conductivity changes located on selected vertical lines. For each of the reconstructed images as well as the ground truth image, conductivity changes located along the selected left and right vertical lines are plotted. In these plots, the notation GT in the legend stands for ground truth, TV stands for total variation method, and TGV stands for total generalized variation method. Reconstructed conductivity distributions from the GREIT algorithm are also demonstrated.

Regularities of radium coprecipitation with barium sulfate from salt solutions

International Nuclear Information System (INIS)

Kudryavskij, Yu.P.; Rakhimova, O.V.

2007-01-01

Coprecipitation of radium with barium sulfate from highly concentrated NaCl solutions is studied, including the effects of the initial solution composition, alkaline reagent (CaO, NaOH), supporting electrolyte (NaCl) concentration, and pH. The process is promoted by high NaCl concentration in the initial solution, which is due to structural transformation and change in the sorption activity of the BaSO 4 precipitate in salt solutions. The results obtained were applied to recovery of radium from process solutions during the development and introduction of improved procedure for disinfection and decontamination of waste yielded by chlorination of loparite concentrates [ru

Regularities of praseodymium oxide dissolution in acids

International Nuclear Information System (INIS)

Savin, V.D.; Elyutin, A.V.; Mikhajlova, N.P.; Eremenko, Z.V.; Opolchenova, N.L.

1989-01-01

The regularities of Pr 2 O 3 , Pr 2 O 5 and Pr(OH) 3 interaction with inorganic acids are studied. pH of the solution and oxidation-reduction potential registrated at 20±1 deg C are the working parameters of studies. It is found that the amount of all oxides dissolved increase in the series of acids - nitric, hydrochloric and sulfuric, in this case for hydrochloric and sulfuric acid it increases in the series of oxides Pr 2 O 3 , Pr 2 O 5 and Pr(OH) 3 . It is noted that Pr 2 O 5 has a high value of oxidation-reduction potential with a positive sign in the whole disslolving range. A low positive value of a redox potential during dissolving belongs to Pr(OH) 3 and in the case of Pr 2 O 3 dissloving redox potential is negative. The schemes of dissolving processes which do not agree with classical assumptions are presented

Exact solutions of linearized Schwinger endash Dyson equation of fermion self-energy

International Nuclear Information System (INIS)

Zhou, B.

1997-01-01

The Schwinger endash Dyson equation of fermion self-energy in the linearization approximation is solved exactly in a theory with gauge and effective four-fermion interactions. Different expressions for the independent solutions, which, respectively, submit to irregular and regular ultraviolet boundary condition are derived and expounded. copyright 1997 American Institute of Physics

Improved prediction of drug-target interactions using regularized least squares integrating with kernel fusion technique

Energy Technology Data Exchange (ETDEWEB)

Hao, Ming; Wang, Yanli, E-mail: ywang@ncbi.nlm.nih.gov; Bryant, Stephen H., E-mail: bryant@ncbi.nlm.nih.gov

2016-02-25

Identification of drug-target interactions (DTI) is a central task in drug discovery processes. In this work, a simple but effective regularized least squares integrating with nonlinear kernel fusion (RLS-KF) algorithm is proposed to perform DTI predictions. Using benchmark DTI datasets, our proposed algorithm achieves the state-of-the-art results with area under precision–recall curve (AUPR) of 0.915, 0.925, 0.853 and 0.909 for enzymes, ion channels (IC), G protein-coupled receptors (GPCR) and nuclear receptors (NR) based on 10 fold cross-validation. The performance can further be improved by using a recalculated kernel matrix, especially for the small set of nuclear receptors with AUPR of 0.945. Importantly, most of the top ranked interaction predictions can be validated by experimental data reported in the literature, bioassay results in the PubChem BioAssay database, as well as other previous studies. Our analysis suggests that the proposed RLS-KF is helpful for studying DTI, drug repositioning as well as polypharmacology, and may help to accelerate drug discovery by identifying novel drug targets. - Graphical abstract: Flowchart of the proposed RLS-KF algorithm for drug-target interaction predictions. - Highlights: • A nonlinear kernel fusion algorithm is proposed to perform drug-target interaction predictions. • Performance can further be improved by using the recalculated kernel. • Top predictions can be validated by experimental data.

Improved prediction of drug-target interactions using regularized least squares integrating with kernel fusion technique

International Nuclear Information System (INIS)

Hao, Ming; Wang, Yanli; Bryant, Stephen H.

2016-01-01

Identification of drug-target interactions (DTI) is a central task in drug discovery processes. In this work, a simple but effective regularized least squares integrating with nonlinear kernel fusion (RLS-KF) algorithm is proposed to perform DTI predictions. Using benchmark DTI datasets, our proposed algorithm achieves the state-of-the-art results with area under precision–recall curve (AUPR) of 0.915, 0.925, 0.853 and 0.909 for enzymes, ion channels (IC), G protein-coupled receptors (GPCR) and nuclear receptors (NR) based on 10 fold cross-validation. The performance can further be improved by using a recalculated kernel matrix, especially for the small set of nuclear receptors with AUPR of 0.945. Importantly, most of the top ranked interaction predictions can be validated by experimental data reported in the literature, bioassay results in the PubChem BioAssay database, as well as other previous studies. Our analysis suggests that the proposed RLS-KF is helpful for studying DTI, drug repositioning as well as polypharmacology, and may help to accelerate drug discovery by identifying novel drug targets. - Graphical abstract: Flowchart of the proposed RLS-KF algorithm for drug-target interaction predictions. - Highlights: • A nonlinear kernel fusion algorithm is proposed to perform drug-target interaction predictions. • Performance can further be improved by using the recalculated kernel. • Top predictions can be validated by experimental data.

Note: Nonpolar solute partial molar volume response to attractive interactions with water

Energy Technology Data Exchange (ETDEWEB)

Williams, Steven M.; Ashbaugh, Henry S., E-mail: hanka@tulane.edu [Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118 (United States)

2014-01-07

The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

Note: Nonpolar solute partial molar volume response to attractive interactions with water.

Science.gov (United States)

Williams, Steven M; Ashbaugh, Henry S

2014-01-07

The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

Prediction of thermodynamic instabilities of protein solutions from simple protein–protein interactions

International Nuclear Information System (INIS)

D’Agostino, Tommaso; Solana, José Ramón; Emanuele, Antonio

2013-01-01

Highlights: ► We propose a model of effective protein–protein interaction embedding solvent effects. ► A previous square-well model is enhanced by giving to the interaction a free energy character. ► The temperature dependence of the interaction is due to entropic effects of the solvent. ► The validity of the original SW model is extended to entropy driven phase transitions. ► We get good fits for lysozyme and haemoglobin spinodal data taken from literature. - Abstract: Statistical thermodynamics of protein solutions is often studied in terms of simple, microscopic models of particles interacting via pairwise potentials. Such modelling can reproduce the short range structure of protein solutions at equilibrium and predict thermodynamics instabilities of these systems. We introduce a square well model of effective protein–protein interaction that embeds the solvent’s action. We modify an existing model [45] by considering a well depth having an explicit dependence on temperature, i.e. an explicit free energy character, thus encompassing the statistically relevant configurations of solvent molecules around proteins. We choose protein solutions exhibiting demixing upon temperature decrease (lysozyme, enthalpy driven) and upon temperature increase (haemoglobin, entropy driven). We obtain satisfactory fits of spinodal curves for both the two proteins without adding any mean field term, thus extending the validity of the original model. Our results underline the solvent role in modulating or stretching the interaction potential

Singular tachyon kinks from regular profiles

International Nuclear Information System (INIS)

Copeland, E.J.; Saffin, P.M.; Steer, D.A.

2003-01-01

We demonstrate how Sen's singular kink solution of the Born-Infeld tachyon action can be constructed by taking the appropriate limit of initially regular profiles. It is shown that the order in which different limits are taken plays an important role in determining whether or not such a solution is obtained for a wide class of potentials. Indeed, by introducing a small parameter into the action, we are able circumvent the results of a recent paper which derived two conditions on the asymptotic tachyon potential such that the singular kink could be recovered in the large amplitude limit of periodic solutions. We show that this is explained by the non-commuting nature of two limits, and that Sen's solution is recovered if the order of the limits is chosen appropriately

Pfaffian Solutions and Resonant Interaction Properties of a Coupled BKP Lattice

International Nuclear Information System (INIS)

Zhao Hai-Qiong; Yu Guo-Fu

2014-01-01

In this paper, we give a coupled lattice equation with the help of Hirota operators, which comes from a special BKP lattice. Two-soliton and three-soliton solutions to the coupled system are constructed. Furthermore, resonant interaction of the two-soliton solution is analyzed in detail. Under some special resonant condition, it is shown that low soliton can propagate faster than high one. Finally, the N-soliton solution is presented in the Pfaffian form. (general)

Interaction mode and nanoparticle formation of bovine serum albumin and anthocyanin in three buffer solutions

International Nuclear Information System (INIS)

Zhou, Rui; Dong, Xueyan; Song, Lanlan; Jing, Hao

2014-01-01

Investigation of interaction mode of bovine serum albumin (BSA) and anthocyanin (ACN) in different solutions will help us understand the interaction mechanism and functional change of bioactive small molecule and biomacromolecule. This study investigated the binding mode, including binding constant, number of binding sites, binding force of BSA and ACN interaction in three buffer solutions of phosphate (PBS), sodium chloride (NaCl), and PBS-NaCl, using fluorescence spectroscopy and synchronous fluorescence spectroscopy. Formation and characteristics of BSA–ACN complex were also investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that ACN could interact with BSA at both tyrosine (Tyr) and tryptophan (Trp) residues through both hydrogen bonds and van der Waals force, and the same binding mode was seen in dH 2 O and three buffer solutions. The value of binding constant K was decreased as the temperature increased from 298 K to 308 K, and the decreasing degree was in the order of dH 2 O (9.0×10 4 )>NaCl (2.64×10 4 )/PBS (2.37×10 4 )>PBS-NaCl (0.88×10 4 ), which was inversely correlated with the ionic strength of the buffer solutions of PBS-NaCl>NaCl>PBS. It indicated that stability of BSA–ACN complex was affected most in dH 2 O than in three buffer solutions. The BSA and ACN interaction led to formation of BSA–ACN nanoparticles. The sizes of BSA–ACN nanoparticles in dH 2 O were smaller than that in three buffer solutions, which correlated with stronger binding force between BSA and ACN in dH 2 O than in three buffer solutions at room temperature (25 °C, 298 K). - Highlights: • We report the influences of four solutions on the BSA–ACN interaction. • We report the relationship between BSA–ACN interaction and particle size of complex. • The stability of BSA–ACN complex was affected most in dH 2 O than in buffer solutions

A regularized matrix factorization approach to induce structured sparse-low-rank solutions in the EEG inverse problem

DEFF Research Database (Denmark)

Montoya-Martinez, Jair; Artes-Rodriguez, Antonio; Pontil, Massimiliano

2014-01-01

We consider the estimation of the Brain Electrical Sources (BES) matrix from noisy electroencephalographic (EEG) measurements, commonly named as the EEG inverse problem. We propose a new method to induce neurophysiological meaningful solutions, which takes into account the smoothness, structured...... sparsity, and low rank of the BES matrix. The method is based on the factorization of the BES matrix as a product of a sparse coding matrix and a dense latent source matrix. The structured sparse-low-rank structure is enforced by minimizing a regularized functional that includes the ℓ21-norm of the coding...... matrix and the squared Frobenius norm of the latent source matrix. We develop an alternating optimization algorithm to solve the resulting nonsmooth-nonconvex minimization problem. We analyze the convergence of the optimization procedure, and we compare, under different synthetic scenarios...

Bypassing the Limits of Ll Regularization: Convex Sparse Signal Processing Using Non-Convex Regularization

Science.gov (United States)

Parekh, Ankit

Sparsity has become the basis of some important signal processing methods over the last ten years. Many signal processing problems (e.g., denoising, deconvolution, non-linear component analysis) can be expressed as inverse problems. Sparsity is invoked through the formulation of an inverse problem with suitably designed regularization terms. The regularization terms alone encode sparsity into the problem formulation. Often, the ℓ1 norm is used to induce sparsity, so much so that ℓ1 regularization is considered to be `modern least-squares'. The use of ℓ1 norm, as a sparsity-inducing regularizer, leads to a convex optimization problem, which has several benefits: the absence of extraneous local minima, well developed theory of globally convergent algorithms, even for large-scale problems. Convex regularization via the ℓ1 norm, however, tends to under-estimate the non-zero values of sparse signals. In order to estimate the non-zero values more accurately, non-convex regularization is often favored over convex regularization. However, non-convex regularization generally leads to non-convex optimization, which suffers from numerous issues: convergence may be guaranteed to only a stationary point, problem specific parameters may be difficult to set, and the solution is sensitive to the initialization of the algorithm. The first part of this thesis is aimed toward combining the benefits of non-convex regularization and convex optimization to estimate sparse signals more effectively. To this end, we propose to use parameterized non-convex regularizers with designated non-convexity and provide a range for the non-convex parameter so as to ensure that the objective function is strictly convex. By ensuring convexity of the objective function (sum of data-fidelity and non-convex regularizer), we can make use of a wide variety of convex optimization algorithms to obtain the unique global minimum reliably. The second part of this thesis proposes a non-linear signal

Perturbation-Based Regularization for Signal Estimation in Linear Discrete Ill-posed Problems

KAUST Repository

Suliman, Mohamed Abdalla Elhag; Ballal, Tarig; Al-Naffouri, Tareq Y.

2016-01-01

Estimating the values of unknown parameters from corrupted measured data faces a lot of challenges in ill-posed problems. In such problems, many fundamental estimation methods fail to provide a meaningful stabilized solution. In this work, we propose a new regularization approach and a new regularization parameter selection approach for linear least-squares discrete ill-posed problems. The proposed approach is based on enhancing the singular-value structure of the ill-posed model matrix to acquire a better solution. Unlike many other regularization algorithms that seek to minimize the estimated data error, the proposed approach is developed to minimize the mean-squared error of the estimator which is the objective in many typical estimation scenarios. The performance of the proposed approach is demonstrated by applying it to a large set of real-world discrete ill-posed problems. Simulation results demonstrate that the proposed approach outperforms a set of benchmark regularization methods in most cases. In addition, the approach also enjoys the lowest runtime and offers the highest level of robustness amongst all the tested benchmark regularization methods.

Perturbation-Based Regularization for Signal Estimation in Linear Discrete Ill-posed Problems

KAUST Repository

Suliman, Mohamed Abdalla Elhag

2016-11-29

Estimating the values of unknown parameters from corrupted measured data faces a lot of challenges in ill-posed problems. In such problems, many fundamental estimation methods fail to provide a meaningful stabilized solution. In this work, we propose a new regularization approach and a new regularization parameter selection approach for linear least-squares discrete ill-posed problems. The proposed approach is based on enhancing the singular-value structure of the ill-posed model matrix to acquire a better solution. Unlike many other regularization algorithms that seek to minimize the estimated data error, the proposed approach is developed to minimize the mean-squared error of the estimator which is the objective in many typical estimation scenarios. The performance of the proposed approach is demonstrated by applying it to a large set of real-world discrete ill-posed problems. Simulation results demonstrate that the proposed approach outperforms a set of benchmark regularization methods in most cases. In addition, the approach also enjoys the lowest runtime and offers the highest level of robustness amongst all the tested benchmark regularization methods.

Interaction of gypsum with lead in aqueous solutions

International Nuclear Information System (INIS)

Astilleros, J.M.; Godelitsas, A.; Rodriguez-Blanco, J.D.; Fernandez-Diaz, L.; Prieto, M.; Lagoyannis, A.; Harissopulos, S.

2010-01-01

Sorption processes on mineral surfaces are a critical factor in controlling the distribution and accumulation of potentially harmful metals in the environment. This work investigates the effectiveness of gypsum (CaSO 4 .2H 2 O) to sequester Pb. The interaction of gypsum fragments with Pb-bearing solutions (10, 100 and 1000 mg/L) was monitored by performing macroscopic batch-type experiments conducted at room temperature. The aqueous phase composition was periodically determined by Atomic Absorption Spectrometry (AAS), Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Regardless of the [Pb aq ] initial , a [Pb aq ] final aq ] initial ≥ 100 mg/L and significantly slower (t > 1 week) for [Pb aq ] initial = 10 mg/L. Speciation calculations revealed that after a long time of interaction (1 month), all the solutions reached equilibrium with respect to both gypsum and anglesite. For [Pb aq ] initial ≥ 100 mg/L, sorption takes place mainly via the rapid dissolution of gypsum and the simultaneous formation of anglesite both on the gypsum surface and in the bulk solution. In the case of [Pb aq ] initial = 10 mg/L, no anglesite precipitation was observed, but surface spectroscopy (proton Rutherford Backscattering Spectroscopy, p-RBS) confirmed the formation of Pb-bearing surface layers on the (0 1 0) gypsum surface in this case also. This study shows that the surface of gypsum can play an important role in the attenuation of Pb in contaminated waters.

Bounded Perturbation Regularization for Linear Least Squares Estimation

KAUST Repository

Ballal, Tarig

2017-10-18

This paper addresses the problem of selecting the regularization parameter for linear least-squares estimation. We propose a new technique called bounded perturbation regularization (BPR). In the proposed BPR method, a perturbation with a bounded norm is allowed into the linear transformation matrix to improve the singular-value structure. Following this, the problem is formulated as a min-max optimization problem. Next, the min-max problem is converted to an equivalent minimization problem to estimate the unknown vector quantity. The solution of the minimization problem is shown to converge to that of the ℓ2 -regularized least squares problem, with the unknown regularizer related to the norm bound of the introduced perturbation through a nonlinear constraint. A procedure is proposed that combines the constraint equation with the mean squared error (MSE) criterion to develop an approximately optimal regularization parameter selection algorithm. Both direct and indirect applications of the proposed method are considered. Comparisons with different Tikhonov regularization parameter selection methods, as well as with other relevant methods, are carried out. Numerical results demonstrate that the proposed method provides significant improvement over state-of-the-art methods.

Solving ill-posed control problems by stabilized finite element methods: an alternative to Tikhonov regularization

Science.gov (United States)

Burman, Erik; Hansbo, Peter; Larson, Mats G.

2018-03-01

Tikhonov regularization is one of the most commonly used methods for the regularization of ill-posed problems. In the setting of finite element solutions of elliptic partial differential control problems, Tikhonov regularization amounts to adding suitably weighted least squares terms of the control variable, or derivatives thereof, to the Lagrangian determining the optimality system. In this note we show that the stabilization methods for discretely ill-posed problems developed in the setting of convection-dominated convection-diffusion problems, can be highly suitable for stabilizing optimal control problems, and that Tikhonov regularization will lead to less accurate discrete solutions. We consider some inverse problems for Poisson’s equation as an illustration and derive new error estimates both for the reconstruction of the solution from the measured data and reconstruction of the source term from the measured data. These estimates include both the effect of the discretization error and error in the measurements.

Total variation regularization for a backward time-fractional diffusion problem

International Nuclear Information System (INIS)

Wang, Liyan; Liu, Jijun

2013-01-01

Consider a two-dimensional backward problem for a time-fractional diffusion process, which can be considered as image de-blurring where the blurring process is assumed to be slow diffusion. In order to avoid the over-smoothing effect for object image with edges and to construct a fast reconstruction scheme, the total variation regularizing term and the data residual error in the frequency domain are coupled to construct the cost functional. The well posedness of this optimization problem is studied. The minimizer is sought approximately using the iteration process for a series of optimization problems with Bregman distance as a penalty term. This iteration reconstruction scheme is essentially a new regularizing scheme with coupling parameter in the cost functional and the iteration stopping times as two regularizing parameters. We give the choice strategy for the regularizing parameters in terms of the noise level of measurement data, which yields the optimal error estimate on the iterative solution. The series optimization problems are solved by alternative iteration with explicit exact solution and therefore the amount of computation is much weakened. Numerical implementations are given to support our theoretical analysis on the convergence rate and to show the significant reconstruction improvements. (paper)

A convergence analysis of the iteratively regularized Gauss–Newton method under the Lipschitz condition

International Nuclear Information System (INIS)

Jin Qinian

2008-01-01

In this paper we consider the iteratively regularized Gauss–Newton method for solving nonlinear ill-posed inverse problems. Under merely the Lipschitz condition, we prove that this method together with an a posteriori stopping rule defines an order optimal regularization method if the solution is regular in some suitable sense

A short proof of increased parabolic regularity

Directory of Open Access Journals (Sweden)

Stephen Pankavich

2015-08-01

Full Text Available We present a short proof of the increased regularity obtained by solutions to uniformly parabolic partial differential equations. Though this setting is fairly introductory, our new method of proof, which uses a priori estimates and an inductive method, can be extended to prove analogous results for problems with time-dependent coefficients, advection-diffusion or reaction diffusion equations, and nonlinear PDEs even when other tools, such as semigroup methods or the use of explicit fundamental solutions, are unavailable.

Linear deflectometry - Regularization and experimental design [Lineare deflektometrie - Regularisierung und experimentelles design

KAUST Repository

Balzer, Jonathan

2011-01-01

Specular surfaces can be measured with deflectometric methods. The solutions form a one-parameter family whose properties are discussed in this paper. We show in theory and experiment that the shape sensitivity of solutions decreases with growing distance from the optical center of the imaging component of the sensor system and propose a novel regularization strategy. Recommendations for the construction of a measurement setup aim for benefiting this strategy as well as the contrarian standard approach of regularization by specular stereo. © Oldenbourg Wissenschaftsverlag.

Influence of Solvent-Solvent and Solute-Solvent Interaction Properties on Solvent-Mediated Potential

International Nuclear Information System (INIS)

Zhou Shiqi

2005-01-01

A recently proposed universal calculational recipe for solvent-mediated potential is applied to calculate excess potential of mean force between two large Lennard-Jones (LJ) or hard core attractive Yukawa particles immersed in small LJ solvent bath at supercritical state. Comparison between the present prediction with a hypernetted chain approximation adopted for solute-solute correlation at infinitely dilute limit and existing simulation data shows high accuracy for the region with large separation, and qualitative reliability for the solute particle contact region. The calculational simplicity of the present recipe allows for a detailed investigation on the effect of the solute-solvent and solvent-solvent interaction details on the excess potential of mean force. The resultant conclusion is that gathering of solvent particles near a solute particle leads to repulsive excess PMF, while depletion of solvent particles away from the solute particle leads to attractive excess PMF, and minor change of the solvent-solvent interaction range has large influence on the excess PMF.

Measure solutions for non-local interaction PDEs with two species

Energy Technology Data Exchange (ETDEWEB)

Francesco, Marco Di [Department of Mathematical and Statistical Sciences, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom); Fagioli, Simone [DISIM—Department of Information Engineering, Computer Science and Mathematics, University of L' Aquila, Via Vetoio 1 (Coppito) 67100 L' Aquila (AQ) (Italy)

2013-10-01

This paper presents a systematic existence and uniqueness theory of weak measure solutions for systems of non-local interaction PDEs with two species, which are the PDE counterpart of systems of deterministic interacting particles with two species. The main motivations behind those models arise in cell biology, pedestrian movements, and opinion formation. In case of symmetrizable systems (i.e. with cross-interaction potentials one multiple of the other), we provide a complete existence and uniqueness theory within (a suitable generalization of) the Wasserstein gradient flow theory in Ambrosio et al (2008 Gradient Flows in Metric Spaces and in the Space of Probability Measures (Lectures in Mathematics ETH Zürich) 2nd edn (Basel: Birkhäuser)) and Carrillo et al (2011 Duke Math. J. 156 229–71), which allows the consideration of interaction potentials with a discontinuous gradient at the origin. In the general case of non-symmetrizable systems, we provide an existence result for measure solutions which uses a semi-implicit version of the Jordan–Kinderlehrer–Otto (JKO) scheme (Jordan et al 1998 SIAM J. Math. Anal. 29 1–17), which holds in a reasonable non-smooth setting for the interaction potentials. Uniqueness in the non-symmetrizable case is proven for C{sup 2} potentials using a variant of the method of characteristics. (paper)

Measure solutions for non-local interaction PDEs with two species

International Nuclear Information System (INIS)

Francesco, Marco Di; Fagioli, Simone

2013-01-01

This paper presents a systematic existence and uniqueness theory of weak measure solutions for systems of non-local interaction PDEs with two species, which are the PDE counterpart of systems of deterministic interacting particles with two species. The main motivations behind those models arise in cell biology, pedestrian movements, and opinion formation. In case of symmetrizable systems (i.e. with cross-interaction potentials one multiple of the other), we provide a complete existence and uniqueness theory within (a suitable generalization of) the Wasserstein gradient flow theory in Ambrosio et al (2008 Gradient Flows in Metric Spaces and in the Space of Probability Measures (Lectures in Mathematics ETH Zürich) 2nd edn (Basel: Birkhäuser)) and Carrillo et al (2011 Duke Math. J. 156 229–71), which allows the consideration of interaction potentials with a discontinuous gradient at the origin. In the general case of non-symmetrizable systems, we provide an existence result for measure solutions which uses a semi-implicit version of the Jordan–Kinderlehrer–Otto (JKO) scheme (Jordan et al 1998 SIAM J. Math. Anal. 29 1–17), which holds in a reasonable non-smooth setting for the interaction potentials. Uniqueness in the non-symmetrizable case is proven for C 2 potentials using a variant of the method of characteristics. (paper)

Diverse Regular Employees and Non-regular Employment (Japanese)

OpenAIRE

MORISHIMA Motohiro

2011-01-01

Currently there are high expectations for the introduction of policies related to diverse regular employees. These policies are a response to the problem of disparities between regular and non-regular employees (part-time, temporary, contract and other non-regular employees) and will make it more likely that workers can balance work and their private lives while companies benefit from the advantages of regular employment. In this paper, I look at two issues that underlie this discussion. The ...

Regularity criteria for incompressible magnetohydrodynamics equations in three dimensions

International Nuclear Information System (INIS)

Lin, Hongxia; Du, Lili

2013-01-01

In this paper, we give some new global regularity criteria for three-dimensional incompressible magnetohydrodynamics (MHD) equations. More precisely, we provide some sufficient conditions in terms of the derivatives of the velocity or pressure, for the global regularity of strong solutions to 3D incompressible MHD equations in the whole space, as well as for periodic boundary conditions. Moreover, the regularity criterion involving three of the nine components of the velocity gradient tensor is also obtained. The main results generalize the recent work by Cao and Wu (2010 Two regularity criteria for the 3D MHD equations J. Diff. Eqns 248 2263–74) and the analysis in part is based on the works by Cao C and Titi E (2008 Regularity criteria for the three-dimensional Navier–Stokes equations Indiana Univ. Math. J. 57 2643–61; 2011 Gobal regularity criterion for the 3D Navier–Stokes equations involving one entry of the velocity gradient tensor Arch. Rational Mech. Anal. 202 919–32) for 3D incompressible Navier–Stokes equations. (paper)

Regularity effect in prospective memory during aging

Directory of Open Access Journals (Sweden)

Geoffrey Blondelle

2016-10-01

Full Text Available Background: Regularity effect can affect performance in prospective memory (PM, but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults. Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30, 16 intermediate adults (40–55, and 25 older adults (65–80. The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities. We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding, short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age. Results: A mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young, but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory. Conclusion: Taken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical

Thermodynamics Prediction of Wax Precipitation in Black Oil Using Regular Solution Model and Plus Fraction Characterization

Directory of Open Access Journals (Sweden)

Wei Wang

2013-01-01

Full Text Available The precipitation of wax/solid paraffin during production, transportation, and processing of crude oil is a serious problem. It is essential to have a reliable model to predict the wax appearance temperature and the amount of solid precipitated at different conditions. This paper presents a work to predict the solid precipitation based on solid-liquid equilibrium with regular solution-molecular thermodynamic theory and characterization of the crude oil plus fraction. Due to the differences of solubility characteristics between solid and liquid phase, the solubility parameters of liquid and solid phase are calculated by a modified model. The heat capacity change between solid and liquid phase is considered and estimated in the thermodynamic model. An activity coefficient based thermodynamic method combined with two characteristic methods to calculate wax precipitation in crude oil, especially heavy oil, has been tested with experimental data. The results show that the wax appearance temperature and the amount of weight precipitated can be predicted well with the experimental data.

Caffeine and Sugars Interact in Aqueous Solutions: A Simulation and NMR Study

OpenAIRE

Tavagnacco, Letizia; Engström, Olof; Schnupf, Udo; Saboungi, Marie-Louise; Himmel, Michael; Widmalm, Göran; Cesàro, Attilio; Brady, John W.

2012-01-01

Molecular dynamics simulations were carried out on several systems of caffeine interacting with simple sugars. These included a single caffeine molecule in a 3 molal solution of α-D-glucopyranose, at a caffeine concentration of 0.083 molal; a single caffeine in a 3 molal solution of β-D-glucopyranose, and a single caffeine molecule in a 1.08 molal solution of sucrose (table sugar). Parallel Nuclear Magnetic Resonance titration experiments were carried out on the same solutions under similar c...

A regularization method for extrapolation of solar potential magnetic fields

Science.gov (United States)

Gary, G. A.; Musielak, Z. E.

1992-01-01

The mathematical basis of a Tikhonov regularization method for extrapolating the chromospheric-coronal magnetic field using photospheric vector magnetograms is discussed. The basic techniques show that the Cauchy initial value problem can be formulated for potential magnetic fields. The potential field analysis considers a set of linear, elliptic partial differential equations. It is found that, by introducing an appropriate smoothing of the initial data of the Cauchy potential problem, an approximate Fourier integral solution is found, and an upper bound to the error in the solution is derived. This specific regularization technique, which is a function of magnetograph measurement sensitivities, provides a method to extrapolate the potential magnetic field above an active region into the chromosphere and low corona.

Toward robust high resolution fluorescence tomography: a hybrid row-action edge preserving regularization

Science.gov (United States)

Behrooz, Ali; Zhou, Hao-Min; Eftekhar, Ali A.; Adibi, Ali

2011-02-01

Depth-resolved localization and quantification of fluorescence distribution in tissue, called Fluorescence Molecular Tomography (FMT), is highly ill-conditioned as depth information should be extracted from limited number of surface measurements. Inverse solvers resort to regularization algorithms that penalize Euclidean norm of the solution to overcome ill-posedness. While these regularization algorithms offer good accuracy, their smoothing effects result in continuous distributions which lack high-frequency edge-type features of the actual fluorescence distribution and hence limit the resolution offered by FMT. We propose an algorithm that penalizes the total variation (TV) norm of the solution to preserve sharp transitions and high-frequency components in the reconstructed fluorescence map while overcoming ill-posedness. The hybrid algorithm is composed of two levels: 1) An Algebraic Reconstruction Technique (ART), performed on FMT data for fast recovery of a smooth solution that serves as an initial guess for the iterative TV regularization, 2) A time marching TV regularization algorithm, inspired by the Rudin-Osher-Fatemi TV image restoration, performed on the initial guess to further enhance the resolution and accuracy of the reconstruction. The performance of the proposed method in resolving fluorescent tubes inserted in a liquid tissue phantom imaged by a non-contact CW trans-illumination FMT system is studied and compared to conventional regularization schemes. It is observed that the proposed method performs better in resolving fluorescence inclusions at higher depths.

A Differential Quadrature Procedure with Regularization of the Dirac-delta Function for Numerical Solution of Moving Load Problem

Directory of Open Access Journals (Sweden)

S. A. Eftekhari

Full Text Available AbstractThe differential quadrature method (DQM is one of the most elegant and efficient methods for the numerical solution of partial differential equations arising in engineering and applied sciences. It is simple to use and also straightforward to implement. However, the DQM is well-known to have some difficulty when applied to partial differential equations involving singular functions like the Dirac-delta function. This is caused by the fact that the Dirac-delta function cannot be directly discretized by the DQM. To overcome this difficulty, this paper presents a simple differential quadrature procedure in which the Dirac-delta function is replaced by regularized smooth functions. By regularizing the Dirac-delta function, such singular function is treated as non-singular functions and can be easily and directly discretized using the DQM. To demonstrate the applicability and reliability of the proposed method, it is applied here to solve some moving load problems of beams and rectangular plates, where the location of the moving load is described by a time-dependent Dirac-delta function. The results generated by the proposed method are compared with analytical and numerical results available in the literature. Numerical results reveal that the proposed method can be used as an efficient tool for dynamic analysis of beam- and plate-type structures traversed by moving dynamic loads.

Lump solutions with interaction phenomena in the (2+1)-dimensional Ito equation

Science.gov (United States)

Zou, Li; Yu, Zong-Bing; Tian, Shou-Fu; Feng, Lian-Li; Li, Jin

2018-03-01

In this paper, we consider the (2+1)-dimensional Ito equation, which was introduced by Ito. By considering the Hirota’s bilinear method, and using the positive quadratic function, we obtain some lump solutions of the Ito equation. In order to ensure rational localization and analyticity of these lump solutions, some sufficient and necessary conditions are provided on the parameters that appeared in the solutions. Furthermore, the interaction solutions between lump solutions and the stripe solitons are discussed by combining positive quadratic function with exponential function. Finally, the dynamic properties of these solutions are shown via the way of graphical analysis by selecting appropriate values of the parameters.

Strain amplitude-dependent anelasticity in Cu-Ni solid solution due to thermally activated and athermal dislocation-point obstacle interactions

Science.gov (United States)

Kustov, S.; Gremaud, G.; Benoit, W.; Golyandin, S.; Sapozhnikov, K.; Nishino, Y.; Asano, S.

1999-02-01

Experimental investigations of the internal friction and the Young's modulus defect in single crystals of Cu-(1.3-7.6) at. % Ni have been performed for 7-300 K over a wide range of oscillatory strain amplitudes. Extensive data have been obtained at a frequency of vibrations around 100 kHz and compared with the results obtained for the same crystals at a frequency of ˜1 kHz. The strain amplitude dependence of the anelastic strain amplitude and the average friction stress acting on a dislocation due to solute atoms are also analyzed. Several stages in the strain amplitude dependence of the internal friction and the Young's modulus defect are revealed for all of the alloy compositions, at different temperatures and in different frequency ranges. For the 100 kHz frequency, low temperatures and low strain amplitudes (˜10-7-10-5), the amplitude-dependent internal friction and the Young's modulus defect are essentially temperature independent, and are ascribed to a purely hysteretic internal friction component. At higher strain amplitudes, a transition stage and a steep strain amplitude dependence of the internal friction and the Young's modulus defect are observed, followed by saturation at the highest strain amplitudes employed. These stages are temperature and frequency dependent and are assumed to be due to thermally activated motion of dislocations. We suggest that the observed regularities in the entire strain amplitude, temperature and frequency ranges correspond to a motion of dislocations in a two-component system of obstacles: weak but long-range ones, due to the elastic interaction of dislocations with solute atoms distributed in the bulk of the crystal; and strong short-range ones, due to the interaction of dislocations with solute atoms distributed close to dislocation glide planes. Based on these assumptions, a qualitative explanation is given for the variety of experimental observations.

Analysis of the iteratively regularized Gauss-Newton method under a heuristic rule

Science.gov (United States)

Jin, Qinian; Wang, Wei

2018-03-01

The iteratively regularized Gauss-Newton method is one of the most prominent regularization methods for solving nonlinear ill-posed inverse problems when the data is corrupted by noise. In order to produce a useful approximate solution, this iterative method should be terminated properly. The existing a priori and a posteriori stopping rules require accurate information on the noise level, which may not be available or reliable in practical applications. In this paper we propose a heuristic selection rule for this regularization method, which requires no information on the noise level. By imposing certain conditions on the noise, we derive a posteriori error estimates on the approximate solutions under various source conditions. Furthermore, we establish a convergence result without using any source condition. Numerical results are presented to illustrate the performance of our heuristic selection rule.

Boundary Equations and Regularity Theory for Geometric Variational Systems with Neumann Data

Science.gov (United States)

Schikorra, Armin

2018-02-01

We study boundary regularity of maps from two-dimensional domains into manifolds which are critical with respect to a generic conformally invariant variational functional and which, at the boundary, intersect perpendicularly with a support manifold. For example, harmonic maps, or H-surfaces, with a partially free boundary condition. In the interior it is known, by the celebrated work of Rivière, that these maps satisfy a system with an antisymmetric potential, from which one can derive the interior regularity of the solution. Avoiding a reflection argument, we show that these maps satisfy along the boundary a system of equations which also exhibits a (nonlocal) antisymmetric potential that combines information from the interior potential and the geometric Neumann boundary condition. We then proceed to show boundary regularity for solutions to such systems.

Geometrical bucklings for two-dimensional regular polygonal regions using the finite Fourier transformation

International Nuclear Information System (INIS)

Mori, N.; Kobayashi, K.

1996-01-01

A two-dimensional neutron diffusion equation is solved for regular polygonal regions by the finite Fourier transformation, and geometrical bucklings are calculated for regular 3-10 polygonal regions. In the case of the regular triangular region, it is found that a simple and rigorous analytic solution is obtained for the geometrical buckling and the distribution of the neutron current along the outer boundary. (author)

Regularization Techniques for Linear Least-Squares Problems

KAUST Repository

Suliman, Mohamed

2016-04-01

Linear estimation is a fundamental branch of signal processing that deals with estimating the values of parameters from a corrupted measured data. Throughout the years, several optimization criteria have been used to achieve this task. The most astonishing attempt among theses is the linear least-squares. Although this criterion enjoyed a wide popularity in many areas due to its attractive properties, it appeared to suffer from some shortcomings. Alternative optimization criteria, as a result, have been proposed. These new criteria allowed, in one way or another, the incorporation of further prior information to the desired problem. Among theses alternative criteria is the regularized least-squares (RLS). In this thesis, we propose two new algorithms to find the regularization parameter for linear least-squares problems. In the constrained perturbation regularization algorithm (COPRA) for random matrices and COPRA for linear discrete ill-posed problems, an artificial perturbation matrix with a bounded norm is forced into the model matrix. This perturbation is introduced to enhance the singular value structure of the matrix. As a result, the new modified model is expected to provide a better stabilize substantial solution when used to estimate the original signal through minimizing the worst-case residual error function. Unlike many other regularization algorithms that go in search of minimizing the estimated data error, the two new proposed algorithms are developed mainly to select the artifcial perturbation bound and the regularization parameter in a way that approximately minimizes the mean-squared error (MSE) between the original signal and its estimate under various conditions. The first proposed COPRA method is developed mainly to estimate the regularization parameter when the measurement matrix is complex Gaussian, with centered unit variance (standard), and independent and identically distributed (i.i.d.) entries. Furthermore, the second proposed COPRA

Soliton solutions to the fifth-order Korteweg-de Vries equation and their applications to surface and internal water waves

Science.gov (United States)

Khusnutdinova, K. R.; Stepanyants, Y. A.; Tranter, M. R.

2018-02-01

We study solitary wave solutions of the fifth-order Korteweg-de Vries equation which contains, besides the traditional quadratic nonlinearity and third-order dispersion, additional terms including cubic nonlinearity and fifth order linear dispersion, as well as two nonlinear dispersive terms. An exact solitary wave solution to this equation is derived, and the dependence of its amplitude, width, and speed on the parameters of the governing equation is studied. It is shown that the derived solution can represent either an embedded or regular soliton depending on the equation parameters. The nonlinear dispersive terms can drastically influence the existence of solitary waves, their nature (regular or embedded), profile, polarity, and stability with respect to small perturbations. We show, in particular, that in some cases embedded solitons can be stable even with respect to interactions with regular solitons. The results obtained are applicable to surface and internal waves in fluids, as well as to waves in other media (plasma, solid waveguides, elastic media with microstructure, etc.).

Ultrafast spontaneous emission modulation of graphene quantum dots interacting with Ag nanoparticles in solution

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jianwei [Department of Physics, Shanghai University, Shanghai 200444 (China); Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); Lu, Jian, E-mail: luj@sari.ac.cn; Wang, Zhongyang, E-mail: wangzy@sari.ac.cn [Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); Wang, Liang [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444 (China); Tian, Linfan [Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 (China); Deng, Xingxia [Research Center of Quantum Macro-Phenomenon and Application, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Tian, Lijun [Department of Physics, Shanghai University, Shanghai 200444 (China); Pan, Dengyu [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China)

2016-07-11

We investigated the strong interaction between graphene quantum dots and silver nanoparticles in solution using time-resolved photoluminescence techniques. In solution, the silver nanoparticles are surrounded by graphene quantum dots and interacted with graphene quantum dots through exciton-plasmon coupling. An ultrafast spontaneous emission process (lifetime 27 ps) was observed in such a mixed solution. This ultrafast lifetime corresponds to the emission rate exceeding 35 GHz, with the purcell enhancement by a factor of ∼12. These experiment results pave the way for the realization of future high speed light sources applications.

Gamma regularization based reconstruction for low dose CT

International Nuclear Information System (INIS)

Zhang, Junfeng; Chen, Yang; Hu, Yining; Luo, Limin; Shu, Huazhong; Li, Bicao; Liu, Jin; Coatrieux, Jean-Louis

2015-01-01

Reducing the radiation in computerized tomography is today a major concern in radiology. Low dose computerized tomography (LDCT) offers a sound way to deal with this problem. However, more severe noise in the reconstructed CT images is observed under low dose scan protocols (e.g. lowered tube current or voltage values). In this paper we propose a Gamma regularization based algorithm for LDCT image reconstruction. This solution is flexible and provides a good balance between the regularizations based on l 0 -norm and l 1 -norm. We evaluate the proposed approach using the projection data from simulated phantoms and scanned Catphan phantoms. Qualitative and quantitative results show that the Gamma regularization based reconstruction can perform better in both edge-preserving and noise suppression when compared with other norms. (paper)

Assorted interactions of amino acids prevailing in aqueous vitamin C solutions probed by physicochemical and ab-initio contrivances

Science.gov (United States)

Das, Koyeli; Roy, Milan Chandra; Rajbanshi, Biplab; Roy, Mahendra Nath

2017-11-01

Qualitative and quantitative analysis of molecular interaction prevailing in tyrosine and tryptophan in aqueous solution of vitamin C have been probed by thermophysical properties. The apparent molar volume (ϕV), viscosity B-coefficient, molal refraction (RM) of tyrosine and tryptophan have been studied in aqueous vitamin C solutions at diverse temperatures via Masson equation which deduced solute-solvent and solute-solute interactions, respectively. Spectroscopic study along with physicochemical and computational techniques provides lots of interesting and highly significant insights of the model biological systems. The overall results established strong solute-solvent interactions between studied amino acids and vitamin C mixture in the ternary solutions.

Regularity of solutions of a phase field model

KAUST Repository

Amler, Thomas; Botkin, Nikolai D.; Hoffmann, Karl Heinz; Ruf, K. A.

2013-01-01

are proved in the case of nonsmooth initial data. Continuity of solutions with respect to time is established. In particular, it is shown that the governing initial boundary value problem can be considered as a dynamical system. © 2013 International Press.

Interaction Between Cyanine Dye IR-783 and Polystyrene Nanoparticles in Solution.

Science.gov (United States)

Zhang, Yunzhi; Xu, Hui; Casabianca, Leah B

2018-05-17

The interactions between small molecule drugs or dyes and nanoparticles are important to the use of nanoparticles in medicine. Noncovalent adsorption of dyes on nanoparticle surfaces is also important to the development of nanoparticle dual-use imaging contrast agents. In the present work, solution-state NMR is used to examine the noncovalent interaction between a near-infrared cyanine dye and the surface of polystyrene nanoparticles in solution. Using 1D proton NMR, we can approximate the number of dye molecules that associate with each nanoparticle for different sized nanoparticles. Saturation-Transfer Difference (STD)-NMR was also used to show that protons near the positively-charged nitrogen in the dye are more strongly associated with the negatively-charged nanoparticle surface than protons near the negatively-charged sulfate groups of the dye. The methods described here can be used to study similar drug or dye molecules interacting with the surface of organic nanoparticles. This article is protected by copyright. All rights reserved.

Weak solutions for Euler systems with non-local interactions

Czech Academy of Sciences Publication Activity Database

Carrillo, J. A.; Feireisl, Eduard; Gwiazda, P.; Swierczewska-Gwiazda, A.

2017-01-01

Roč. 95, č. 3 (2017), s. 705-724 ISSN 0024-6107 EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : Euler system * dissipative solutions * Newtonian interaction Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.895, year: 2016 http://onlinelibrary.wiley.com/doi/10.1112/jlms.12027/abstract

Volumetric, ultrasonic and viscometric studies of solute–solute and solute–solvent interactions of l-threonine in aqueous-sucrose solutions at different temperatures

International Nuclear Information System (INIS)

Nain, Anil Kumar; Pal, Renu; Neetu

2013-01-01

Highlights: • The study reports density, ultrasonic speed and viscosity data of l-threonine in aqueous-sucrose solutions. • The study elucidates interactions of l-threonine with sucrose in aqueous media. • Provides data to estimate physicochemical properties of proteins in these media. • Correlates physicochemical properties of l-threonine with its behaviour in aqueous-sucrose solutions. -- Abstract: Densities, ρ of solutions of l-threonine in aqueous-sucrose solvents 5%, 10%, 15%, and 20% of sucrose, w/w in water at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K; and ultrasonic speeds, u and viscosities, η of these solutions at 298.15, 303.15, 308.15, 313.15, and 318.15 K were measured at atmospheric pressure. From these experimental results, the apparent molar volume, V ϕ , limiting apparent molar volume, V ϕ ∘ and the slope, S v , apparent molar compressibility, K s,ϕ , limiting apparent molar compressibility, K s,ϕ ∘ and the slope, S k , transfer volume, V ϕ,tr ∘ , transfer compressibility, K s,ϕ,tr ∘ , limiting apparent molar expansivity, E ϕ ∘ , Hepler’s constant, (∂ 2 V ϕ ∘ /dT 2 ), Falkenhagen coefficient, A, Jones–Dole coefficient, B and hydration number, n H have been calculated. The results have been interpreted in terms of solute–solvent and solute–solute interactions in these systems. The Gibbs energies of activation of viscous flow per mole of solvent, Δμ 1 ∘number sign and per mole of solute, Δμ 2 ∘number sign were also calculated and discussed in terms of transition state theory. It has been observed that there exist strong solute–solvent interactions in these systems and these interactions increase with increase in sucrose concentration in solution

An Iterative Regularization Method for Identifying the Source Term in a Second Order Differential Equation

Directory of Open Access Journals (Sweden)

Fairouz Zouyed

2015-01-01

Full Text Available This paper discusses the inverse problem of determining an unknown source in a second order differential equation from measured final data. This problem is ill-posed; that is, the solution (if it exists does not depend continuously on the data. In order to solve the considered problem, an iterative method is proposed. Using this method a regularized solution is constructed and an a priori error estimate between the exact solution and its regularized approximation is obtained. Moreover, numerical results are presented to illustrate the accuracy and efficiency of this method.

Interaction of gypsum with lead in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Astilleros, J.M., E-mail: jmastill@geo.ucm.es [Dpto. Cristalografia y Mineralogia, Universidad Complutense de Madrid, Jose Antonio Novais, 2, E-28040 Madrid (Spain); Godelitsas, A. [Department of Mineralogy and Petrology, Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupoli Zographou, 15784 Athens (Greece); Rodriguez-Blanco, J.D. [School of Earth and Environments, Faculty of Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Fernandez-Diaz, L. [Dpto. Cristalografia y Mineralogia, Universidad Complutense de Madrid, Jose Antonio Novais, 2, E-28040 Madrid (Spain); Prieto, M. [Dpto. de Geologia, Universidad de Oviedo, E-30005 Oviedo (Spain); Lagoyannis, A.; Harissopulos, S. [Tandem Accelerator Laboratory, Institute of Nuclear Physics, NCSR ' Demokritos' , GR-15310 Attiki (Greece)

2010-07-15

Sorption processes on mineral surfaces are a critical factor in controlling the distribution and accumulation of potentially harmful metals in the environment. This work investigates the effectiveness of gypsum (CaSO{sub 4}.2H{sub 2}O) to sequester Pb. The interaction of gypsum fragments with Pb-bearing solutions (10, 100 and 1000 mg/L) was monitored by performing macroscopic batch-type experiments conducted at room temperature. The aqueous phase composition was periodically determined by Atomic Absorption Spectrometry (AAS), Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Regardless of the [Pb{sub aq}]{sub initial}, a [Pb{sub aq}]{sub final} < 4 mg/L was always reached. The uptake process was fast (t < 1 h) for [Pb{sub aq}]{sub initial} {>=} 100 mg/L and significantly slower (t > 1 week) for [Pb{sub aq}]{sub initial} = 10 mg/L. Speciation calculations revealed that after a long time of interaction (1 month), all the solutions reached equilibrium with respect to both gypsum and anglesite. For [Pb{sub aq}]{sub initial} {>=} 100 mg/L, sorption takes place mainly via the rapid dissolution of gypsum and the simultaneous formation of anglesite both on the gypsum surface and in the bulk solution. In the case of [Pb{sub aq}]{sub initial} = 10 mg/L, no anglesite precipitation was observed, but surface spectroscopy (proton Rutherford Backscattering Spectroscopy, p-RBS) confirmed the formation of Pb-bearing surface layers on the (0 1 0) gypsum surface in this case also. This study shows that the surface of gypsum can play an important role in the attenuation of Pb in contaminated waters.

Interaction between two parallel plates covered with a polyelectrolyte brush layer in an electrolyte solution.

Science.gov (United States)

Ohshima, Hiroyuki

An approximate analytic expression is derived for the interaction energy between two parallel plates covered with a polyelectrolyte brush layer in an electrolyte solution. The interaction energy has three components: electrostatic interaction energy between two brush layers before and after their contact, steric interaction energy between two brush layers after their contact, and the van der Waals interaction energy between the cores of the plates. It is shown that these three components are of the same order of magnitude and contribute equally to the total interaction energy between two polyelectrolyte-coated plates in an electrolyte solution. On the basis of Derjaguin's approximation, an approximate expression for the interaction energy between two spherical particles covered with polyelectrolyte brush layers is also derived.

Interaction of natural borates with potassium hydroxide solution

International Nuclear Information System (INIS)

Azarova, L.A.; Vinogradov, E.E.; Kudinov, I.B.; Panasyuk, G.P.; Danilov, V.P.

2000-01-01

Interaction of natural borates - inyoite, ulexite and hydroboracite MgCa[B 3 O 4 (OH) 3 ] 2 ·3H 2 O with KOH solution is studied at 50 Deg C by the methods of chemical, x- ray phase, differential thermal analyses and IR spectroscopy. IR spectra points out on island character of forming borates and confirms the data of x-ray phase and chemical analyses about presence of asharite and calcium hydrous borate in resulting products. Hydroboracite (chain structure) under the action of potassium hydroxide passes into borates of magnesium and calcium with island structure and in this case boron transforms partially into liquid phase. When potassium hydroxide interacts with inyoite and ulexite calcium hydroxide and roentgenoamorphous boron-containing product precipitate [ru

Regularization ambiguities in loop quantum gravity

International Nuclear Information System (INIS)

Perez, Alejandro

2006-01-01

One of the main achievements of loop quantum gravity is the consistent quantization of the analog of the Wheeler-DeWitt equation which is free of ultraviolet divergences. However, ambiguities associated to the intermediate regularization procedure lead to an apparently infinite set of possible theories. The absence of an UV problem--the existence of well-behaved regularization of the constraints--is intimately linked with the ambiguities arising in the quantum theory. Among these ambiguities is the one associated to the SU(2) unitary representation used in the diffeomorphism covariant 'point-splitting' regularization of the nonlinear functionals of the connection. This ambiguity is labeled by a half-integer m and, here, it is referred to as the m ambiguity. The aim of this paper is to investigate the important implications of this ambiguity. We first study 2+1 gravity (and more generally BF theory) quantized in the canonical formulation of loop quantum gravity. Only when the regularization of the quantum constraints is performed in terms of the fundamental representation of the gauge group does one obtain the usual topological quantum field theory as a result. In all other cases unphysical local degrees of freedom arise at the level of the regulated theory that conspire against the existence of the continuum limit. This shows that there is a clear-cut choice in the quantization of the constraints in 2+1 loop quantum gravity. We then analyze the effects of the ambiguity in 3+1 gravity exhibiting the existence of spurious solutions for higher representation quantizations of the Hamiltonian constraint. Although the analysis is not complete in 3+1 dimensions - due to the difficulties associated to the definition of the physical inner product - it provides evidence supporting the definitions quantum dynamics of loop quantum gravity in terms of the fundamental representation of the gauge group as the only consistent possibilities. If the gauge group is SO(3) we find

Generalisation for regular black holes on general relativity to f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Manuel E. [Universidade Federal do Para Campus Universitario de Abaetetuba, Faculdade de Ciencias Exatas e Tecnologia, Abaetetuba, Para (Brazil); Universidade Federal do Para, Faculdade de Fisica, PPGF, Belem, Para (Brazil); Fabris, Julio C. [Universidade Federal do Espirito Santo, Vitoria, ES (Brazil); National Research Nuclear University MEPhI, Moscow (Russian Federation); Junior, Ednaldo L.B. [Universidade Federal do Para, Faculdade de Fisica, PPGF, Belem, Para (Brazil); Universidade Federal do Para, Campus Universitario de Tucurui, Faculdade de Engenharia da Computacao, Tucurui, Para (Brazil); Marques, Glauber T. [Universidade Federal Rural da Amazonia ICIBE - LASIC, Belem, PA (Brazil)

2016-05-15

IIn this paper, we determine regular black hole solutions using a very general f(R) theory, coupled to a nonlinear electromagnetic field given by a Lagrangian L{sub NED}. The functions f(R) and L{sub NED} are in principle left unspecified. Instead, the model is constructed through a choice of the mass function M(r) presented in the metric coefficients. Solutions which have a regular behaviour of the geometric invariants are found. These solutions have two horizons, the event horizon and the Cauchy horizon. All energy conditions are satisfied in the whole space-time, except the strong energy condition (SEC), which is violated near the Cauchy horizon.We present also a new theorem related to the energy conditions in f(R) gravity, re-obtaining the well-known conditions in the context of general relativity when the geometry of the solution is the same. (orig.)

Analytic regularization of uniform cubic B-spline deformation fields.

Science.gov (United States)

Shackleford, James A; Yang, Qi; Lourenço, Ana M; Shusharina, Nadya; Kandasamy, Nagarajan; Sharp, Gregory C

2012-01-01

Image registration is inherently ill-posed, and lacks a unique solution. In the context of medical applications, it is desirable to avoid solutions that describe physically unsound deformations within the patient anatomy. Among the accepted methods of regularizing non-rigid image registration to provide solutions applicable to medical practice is the penalty of thin-plate bending energy. In this paper, we develop an exact, analytic method for computing the bending energy of a three-dimensional B-spline deformation field as a quadratic matrix operation on the spline coefficient values. Results presented on ten thoracic case studies indicate the analytic solution is between 61-1371x faster than a numerical central differencing solution.

Complete heat transfer solutions of an insulated regular polygonal pipe by using a PWTR model

International Nuclear Information System (INIS)

Wong, K.-L.; Chou, H.-M.; Li, Y.-H.

2004-01-01

The heat transfer characteristics for insulated long regular polygonal (including circular) pipes are analyzed by using the same PWRT model in the present study as that used by Chou and Wong previously [Energy Convers. Manage. 44 (4) (2003) 629]. The thermal resistance of the inner convection term and the pipe conduction term in the heat transfer rate are not neglected in the present study. Thus, the complete heat transfer solution will be obtained. The present results can be applied more extensively to practical situations, such as heat exchangers. The results of the critical thickness t cr and the neutral thickness t e are independent of the values of J (generated by the combined effect of the inner convection term and the pipe conduction term). However, the heat transfer rates are dependent on the values of J. The present study shows that the thermal resistance of the inner convection term and the pipe conduction term cannot be neglected in the heat transfer equation in situations of low to medium inner convection coefficients h i and/or low to medium pipe conductivities K, especially in situations with large pipe sizes or/and great outer convection coefficients h 0

Coordinate-invariant regularization

International Nuclear Information System (INIS)

Halpern, M.B.

1987-01-01

A general phase-space framework for coordinate-invariant regularization is given. The development is geometric, with all regularization contained in regularized DeWitt Superstructures on field deformations. Parallel development of invariant coordinate-space regularization is obtained by regularized functional integration of the momenta. As representative examples of the general formulation, the regularized general non-linear sigma model and regularized quantum gravity are discussed. copyright 1987 Academic Press, Inc

Existence and regularity of solutions of a phase field model for solidification with convection of pure materials in two dimensions

Directory of Open Access Journals (Sweden)

Jose Luiz Boldrini

2003-11-01

Full Text Available We study the existence and regularity of weak solutions of a phase field type model for pure material solidification in presence of natural convection. We assume that the non-stationary solidification process occurs in a two dimensional bounded domain. The governing equations of the model are the phase field equation coupled with a nonlinear heat equation and a modified Navier-Stokes equation. These equations include buoyancy forces modelled by Boussinesq approximation and a Carman-Koseny term to model the flow in mushy regions. Since these modified Navier-Stokes equations only hold in the non-solid regions, which are not known a priori, we have a free boundary-value problem.

Investigations to explore interactions in (polyhydroxy solute + L-ascorbic acid + H2O) solutions at different temperatures: Calorimetric and viscometric approach

International Nuclear Information System (INIS)

Banipal, Parampaul K.; Sharma, Mousmee; Aggarwal, Neha; Banipal, Tarlok S.

2016-01-01

Highlights: • The hydrophilic-hydrophilic interactions predominate at low temperatures. • Enthalpy change for polyol is less exothermic than its parent saccharide. • Δ dil C o p,2,m values suggest structural increase in presence of L-ascorbic acid. • Solutes act as kosmotropes in L-ascorbic acid (aq) solutions as indicated by dB/dT. - Abstract: Isothermal titration micro-calorimeter has been used to measure the enthalpy change (q) of polyhydroxy solutes [(+)-D-xylose, xylitol, (+)-D-glucose, 2-deoxy-D-glucose, (+)-methyl-α-D-glucopyranoside, and (+)-maltose monohydrate] in water and in (0.05, 0.15, and 0.25) mol·kg −1 L-ascorbic acid (aq) solutions at (288.15, 298.15, 308.15, and 318.15) K. Limiting enthalpies of dilution (Δ dil H°) of these solutes were calculated from heat evolved/absorbed during calorimetric experiments. Further thermodynamic quantities such as limiting enthalpies of dilution of transfer (Δ tr Δ dil H°), change in heat capacity (Δ dil C o p,2,m ), and pair (h AB ) and triplet (h ABB ) enthalpic interaction coefficients were also calculated and used to explore the nature of interactions of solutes with cosolute (L-ascorbic acid). The Jones-Dole viscosity B-coefficients for (+)-D-xylose, xylitol, (+)-D-galactose, galactitol, (+)-D-glucose, 2-deoxy-D-glucose, (+)-methyl-α-D-glucopyranoside, and (+)-maltose monohydrate in water and in (0.05, 0.15, 0.25, and 0.35) mol·kg −1 L-ascorbic acid (aq) solutions have been determined from viscosity (η) data measured over temperature range (288.15–318.15) K and at pressure, P = 101.3 kPa. The temperature dependence of B-coefficients (dB/dT), and viscosity B-coefficients of transfer (Δ tr B) of solutes from water to cosolute have also been estimated. These parameters have been discussed in terms of structure-making (kosmotropic) or -breaking (chaotropic) behavior of solutes.

Interaction of sodium monoborate and boric acid with some mono- and disaccharides in aqueous solutions (from data on isomolar solutions method)

International Nuclear Information System (INIS)

Shvarts, E.M.; Ignash, R.T.; Belousova, R.G.

2000-01-01

Interaction of sodium monoborate Na[B(OH) 4 ] and boric acid with D-glucose, D-fructose, D-saccharose and D-lactose in aqueous solution depending on the solution total concentration is studied through the method of isomolar solutions with application of conductometry and polarimetry. It is shown by the D-glucose and D-fructose examples that the method of isomolar solutions leads to results compatible with the data obtained by other methods and it may be applied to other saccharides [ru

Micellar solubilization in strongly interacting binary surfactant systems. [Binary surfactant systems of: dodecyltrimethylammonium chloride + sodium dodecyl sulfate; benzyldimethyltetradecylammonium chloride + tetradecyltrimethylammonium chloride

Energy Technology Data Exchange (ETDEWEB)

Treiner, C. (Universite Pierre et Marie Curie, Paris (France)); Nortz, M.; Vaution, C. (Faculte de Pharmacie de Paris-sud, Chatenay-Malabry (France))

1990-07-01

The apparent partition coefficient P of barbituric acids between micelles and water has been determined in mixed binary surfactant solutions from solubility measurements in the whole micellar composition range. The binary systems chosen ranged from the strongly interacting system dodecyltrimethylammonium chloride + sodium dodecyl sulfate to weakly interacting systems such as benzyldimethyltetradecylammonium chloride + tetradecyltrimethyammonium chloride. In all cases studied, mixed micelle formation is unfavorable to micellar solubilization. A correlation is found between the unlike surfactants interaction energy, as measured by the regular solution parameter {beta} and the solute partition coefficient change upon surfactant mixing. By use of literature data on micellar solubilization in binary surfactant solutions, it is shown that the change of P for solutes which are solubilized by surface adsorption is generally governed by the sign and amplitude of the interaction parameter {beta}.

Effects of molecular interactions and the existence of different molecular forms of sodium fluoresceinate in solutions

International Nuclear Information System (INIS)

Golubeva, N.G.

1989-01-01

The results of measurement of fluorescence and absorption spectra of sodium fluoresceinate (FLNa) in different solutions and blood plasma are presented. The influence of solvent nature, its polarity, medium concentration and acidity on frequency, intensity and shape of fluorescence and absorption lines was analyzed. A general medium effect on fluorescence line spectral absorption was calculated from Lippert's equation. The influence of specific interactions has been analyzed on the example of acid-base interactions and hydrogen bonds in two- and multicomponent solutions. Computer processing of the spectra obtained allows to separate some forms of existing fluorophor molecules and to get data on the dynamics of their changes in different solutions. A special attention was given to the analysis of absorption and fluorescence bands of FLNa at its interaction with different proteins and lipids in solutions. From the analysis of data obtained a number of conclusions was drawn on the state of fluophor at its interactions with biological media. (author)

An adaptive regularization parameter choice strategy for multispectral bioluminescence tomography

Energy Technology Data Exchange (ETDEWEB)

Feng Jinchao; Qin Chenghu; Jia Kebin; Han Dong; Liu Kai; Zhu Shouping; Yang Xin; Tian Jie [Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, P. O. Box 2728, Beijing 100190 (China); College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, P. O. Box 2728, Beijing 100190 (China); Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, P. O. Box 2728, Beijing 100190 (China) and School of Life Sciences and Technology, Xidian University, Xi' an 710071 (China)

2011-11-15

Purpose: Bioluminescence tomography (BLT) provides an effective tool for monitoring physiological and pathological activities in vivo. However, the measured data in bioluminescence imaging are corrupted by noise. Therefore, regularization methods are commonly used to find a regularized solution. Nevertheless, for the quality of the reconstructed bioluminescent source obtained by regularization methods, the choice of the regularization parameters is crucial. To date, the selection of regularization parameters remains challenging. With regards to the above problems, the authors proposed a BLT reconstruction algorithm with an adaptive parameter choice rule. Methods: The proposed reconstruction algorithm uses a diffusion equation for modeling the bioluminescent photon transport. The diffusion equation is solved with a finite element method. Computed tomography (CT) images provide anatomical information regarding the geometry of the small animal and its internal organs. To reduce the ill-posedness of BLT, spectral information and the optimal permissible source region are employed. Then, the relationship between the unknown source distribution and multiview and multispectral boundary measurements is established based on the finite element method and the optimal permissible source region. Since the measured data are noisy, the BLT reconstruction is formulated as l{sub 2} data fidelity and a general regularization term. When choosing the regularization parameters for BLT, an efficient model function approach is proposed, which does not require knowledge of the noise level. This approach only requests the computation of the residual and regularized solution norm. With this knowledge, we construct the model function to approximate the objective function, and the regularization parameter is updated iteratively. Results: First, the micro-CT based mouse phantom was used for simulation verification. Simulation experiments were used to illustrate why multispectral data were used

Dimensional regularization in position space and a forest formula for regularized Epstein-Glaser renormalization

Energy Technology Data Exchange (ETDEWEB)

Keller, Kai Johannes

2010-04-15

The present work contains a consistent formulation of the methods of dimensional regularization (DimReg) and minimal subtraction (MS) in Minkowski position space. The methods are implemented into the framework of perturbative Algebraic Quantum Field Theory (pAQFT). The developed methods are used to solve the Epstein-Glaser recursion for the construction of time-ordered products in all orders of causal perturbation theory. A solution is given in terms of a forest formula in the sense of Zimmermann. A relation to the alternative approach to renormalization theory using Hopf algebras is established. (orig.)

Dimensional regularization in position space and a forest formula for regularized Epstein-Glaser renormalization

International Nuclear Information System (INIS)

Keller, Kai Johannes

2010-04-01

The present work contains a consistent formulation of the methods of dimensional regularization (DimReg) and minimal subtraction (MS) in Minkowski position space. The methods are implemented into the framework of perturbative Algebraic Quantum Field Theory (pAQFT). The developed methods are used to solve the Epstein-Glaser recursion for the construction of time-ordered products in all orders of causal perturbation theory. A solution is given in terms of a forest formula in the sense of Zimmermann. A relation to the alternative approach to renormalization theory using Hopf algebras is established. (orig.)

Investigation of processes of interaction relativistic electrons with the solutions of organic dyes

International Nuclear Information System (INIS)

Buki, A.Yu.; Gokov, S.P.; Kazarinov, Yu.G.; Kalenik, S.A.; Kasilov, V.I.; Kochetov, S.S.; Makhnenko, P.L.; Mel'nitskiy, I.V.; Tverdohvalov, A.V.; Tsyatsko, V.V.; Shopen, O.A.

2014-01-01

Investigation of the processes of interaction of ionizing radiation with complex organic objects can solve a number of fundamental and applied problems in radiation physics, chemistry and biology. In this work we investigated the dose dependence (dose range 1...5MRad) optical density relative concentrations of water, alcohol and glycerine solution following organic dyes: methylene blue - C 16 H 18 N 3 SCl and methyl orange - C 14 H 14 N 3 O 3 SNa, irradiated with an electron beam with an energy of 16MeV. In the analysis of absorption spectra, it was found that water solutions of dyes have less resistance to radiation as compared with the alcohol and glycerol. Also, all solutions of methyl orange less radiation resistant than the methylene blue solution. Analysis of the spectra showed that these relationships are close to linear in the range of doses. To understand the physical and chemical processes occurring in the interaction of relativistic electrons with the studied organic objects were performed the computer simulations of the energy spectra of ions formed due to breaking the chemical bonds of molecules of dye solutions using the program SRIM-2010. The analysis showed that radiation - stimulated chemical processes play a major role in the destruction of the source of organic dye molecules. The remaining processes (interaction of electrons and nuclei, the cascade processes) accounts for about 10% of all molecular breaks.

Study of the chemical interactions of actinide cations in solution at macroscopic concentrations

International Nuclear Information System (INIS)

Maurice, C.

1983-01-01

The aim of this work was to study the interactions of pentavalent neptunium in dodecane-diluted tributyl phosphate with other metallic cations, especially uranium VI and ruthenium present in reprocessing solutions. Pentavalent neptunium on its own was shown to exist in several forms complexed by water and TBP and also to dimerise. In the complex it forms with uranium VI the interaction via the neptunyl oxygen is considerably enhanced in organic solution. Dibutyl phosphoric acid strengthens the interaction between neptunium and uranium. The Np V-ruthenium interaction reveals the existence of a new cation-cation complex; the process takes place in two successive stage and leads to the formation, reinforced and accelerated by HDBP, of a highly to the formation, reinforced and accelerated by HDBP, of a highly stable complex. These results contribute towards a better knowledge of the behaviour of neptunium in the reprocessing operation [fr

Variational analysis of regular mappings theory and applications

CERN Document Server

Ioffe, Alexander D

2017-01-01

This monograph offers the first systematic account of (metric) regularity theory in variational analysis. It presents new developments alongside classical results and demonstrates the power of the theory through applications to various problems in analysis and optimization theory. The origins of metric regularity theory can be traced back to a series of fundamental ideas and results of nonlinear functional analysis and global analysis centered around problems of existence and stability of solutions of nonlinear equations. In variational analysis, regularity theory goes far beyond the classical setting and is also concerned with non-differentiable and multi-valued operators. The present volume explores all basic aspects of the theory, from the most general problems for mappings between metric spaces to those connected with fairly concrete and important classes of operators acting in Banach and finite dimensional spaces. Written by a leading expert in the field, the book covers new and powerful techniques, whic...

Interactions of Chemistry Teachers with Gifted Students in a Regular High-School Chemistry Classroom

Science.gov (United States)

Benny, Naama; Blonder, Ron

2018-01-01

Regular high-school chemistry teachers view gifted students as one of several types of students in a regular (mixed-ability) classroom. Gifted students have a range of unique abilities that characterize their learning process: mostly they differ in three key learning aspects: their faster learning pace, increased depth of understanding, and…

Global regularization method for planar restricted three-body problem

Directory of Open Access Journals (Sweden)

Sharaf M.A.

2015-01-01

Full Text Available In this paper, global regularization method for planar restricted three-body problem is purposed by using the transformation z = x+iy = ν cos n(u+iv, where i = √−1, 0 < ν ≤ 1 and n is a positive integer. The method is developed analytically and computationally. For the analytical developments, analytical solutions in power series of the pseudotime τ are obtained for positions and velocities (u, v, u', v' and (x, y, x˙, y˙ in both regularized and physical planes respectively, the physical time t is also obtained as power series in τ. Moreover, relations between the coefficients of the power series are obtained for two consequent values of n. Also, we developed analytical solutions in power series form for the inverse problem of finding τ in terms of t. As typical examples, three symbolic expressions for the coefficients of the power series were developed in terms of initial values. As to the computational developments, the global regularized equations of motion are developed together with their initial values in forms suitable for digital computations using any differential equations solver. On the other hand, for numerical evolutions of power series, an efficient method depending on the continued fraction theory is provided.

Hydration interactions and stability of soluble microbial products in aqueous solutions.

Science.gov (United States)

Wang, Ling-Ling; Wang, Long-Fei; Ye, Xiao-Dong; Yu, Han-Qing

2013-10-01

Soluble microbial products (SMP) are organic compounds excreted by microorganisms in their metabolism and decay and the main constituents in effluent from biological wastewater treatment systems. They also have an important contribution to the dissolved organic matters in natural aqueous systems. So far the interactions between SMP colloids have not been well explored. In this work, the interactions between SMP colloids in water and salt solutions were studied by using a combination of static and dynamic light scattering, Fourier transform infrared spectra, Zeta potential and acid-base titration techniques. The second osmotic virial coefficient had a larger value in a 750-mM salt solution than that in a 50-mM solution, indicating that repulsion between SMP colloids increased with an increase in salt concentration, which is contrary with the classic Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. Such a repulsion was attributed to water structuring and enhanced by the accumulation of hydrophilic counter ions around SMP colloids and the formed hydration force. The repulsion and hydration effect led to the dispersing and deeper draining structure, accompanied by a decreased hydrodynamic radius and increased diffusion coefficient. This hydration force was related to so-called ion specific effect, and electrolyte sodium chloride had a more substantial effect on hydration force than KCl, CsCl, NaBr and NaI. Our results provide an experimental approach to explore the SMP structures, inter-colloid interactions and confirm the non-DLVO forces. Copyright © 2013 Elsevier Ltd. All rights reserved.

Study of interaction of bismuth, strontium, calcium copper, lead nitrates solutions with sodium oxalate solution with the aim of HTSC synthesis

International Nuclear Information System (INIS)

Danilov, V.P.; Krasnobaeva, O.N.; Nosova, T.A.

1993-01-01

With the aim of developing a new technique for HTSC oxides synthesis on the base of combined sedimentation of hydroxy salts and their heat treatment is studied interaction of bismuth, strontium, calcium, copper and lead nitrates with alkali solution of sodium oxalate. Conditions for total sedimentation of all five metals from the solution are found. The phase composition of interaction products is determined. It is established that they are high-dispersed homogeneous mixture of three phases of variable composition: twin hydroxalate of copper-bismuth, lead hydroxalate and twin oxalate of strontium-calcium. After heat treatment of the phases are obtained the HTSC oxides

Low regularity solutions of the Chern-Simons-Higgs equations in the Lorentz gauge

Directory of Open Access Journals (Sweden)

Nikolaos Bournaveas

2009-09-01

Full Text Available We prove local well-posedness for the 2+1-dimensional Chern-Simons-Higgs equations in the Lorentz gauge with initial data of low regularity. Our result improves earlier results by Huh [10, 11].

Towards a Model of Human Resource Solutions for Achieving Intergenerational Interaction in Organisations

Science.gov (United States)

McGuire, David; By, Rune Todnem; Hutchings, Kate

2007-01-01

Purpose: Achieving intergenerational interaction and avoiding conflict is becoming increasingly difficult in a workplace populated by three generations--Baby Boomers, Generation X-ers and Generation Y-ers. This paper presents a model and proposes HR solutions towards achieving co-operative generational interaction. Design/methodology/approach:…

Citrate-coated silver nanoparticles interactions with effluent organic matter: influence of capping agent and solution conditions

KAUST Repository

Gutierrez, Leonardo

2015-07-31

Fate and transport studies of silver nanoparticles (AgNPs) discharged from urban wastewaters containing effluent organic matter (EfOM) into natural waters represent a key knowledge gap. In this study, EfOM interfacial interactions with AgNPs and their aggregation kinetics were investigated by atomic force microscopy (AFM) and time-resolved dynamic light scattering (TR-DLS), respectively. Two well-characterized EfOM isolates, i.e., wastewater humic (WW humic) and wastewater colloids (WW colloids, a complex mixture of polysaccharides-proteins-lipids), and a River humic isolate of different characteristics were selected. Citrate-coated AgNPs were selected as representative capped-AgNPs. Citrate-coated AgNPs showed a considerable stability in Na+ solutions. However, Ca2+ ions induced aggregation by cation bridging between carboxyl groups on citrate. Although the presence of River humic increased the stability of citrate-coated AgNPs in Na+ solutions due to electrosteric effects, they aggregated in WW humic-containing solutions, indicating the importance of humics characteristics during interactions. Ca2+ ions increased citrate-coated AgNPs aggregation rates in both humic solutions, suggesting cation bridging between carboxyl groups on their structures as a dominant interacting mechanism. Aggregation of citrate-coated AgNPs in WW colloids solutions was significantly faster than those in both humic solutions. Control experiments in urea solution indicated hydrogen bonding as the main interacting mechanism. During AFM experiments, citrate-coated AgNPs showed higher adhesion to WW humic than to River humic, evidencing a consistency between TR-DLS and AFM results. Ca2+ ions increased citrate-coated AgNPs adhesion to both humic isolates. Interestingly, strong WW colloids interactions with citrate caused AFM probe contamination (nanoparticles adsorption) even at low Na+ concentrations, indicating the impact of hydrogen bonding on adhesion. These results suggest the importance

A regularization of the Burgers equation using a filtered convective velocity

International Nuclear Information System (INIS)

Norgard, Greg; Mohseni, Kamran

2008-01-01

This paper examines the properties of a regularization of the Burgers equation in one and multiple dimensions using a filtered convective velocity, which we have dubbed as the convectively filtered Burgers (CFB) equation. A physical motivation behind the filtering technique is presented. An existence and uniqueness theorem for multiple dimensions and a general class of filters is proven. Multiple invariants of motion are found for the CFB equation which are shown to be shared with the viscous and inviscid Burgers equations. Traveling wave solutions are found for a general class of filters and are shown to converge to weak solutions of the inviscid Burgers equation with the correct wave speed. Numerical simulations are conducted in 1D and 2D cases where the shock behavior, shock thickness and kinetic energy decay are examined. Energy spectra are also examined and are shown to be related to the smoothness of the solutions. This approach is presented with the hope of being extended to shock regularization of compressible Euler equations

A regularized vortex-particle mesh method for large eddy simulation

Science.gov (United States)

Spietz, H. J.; Walther, J. H.; Hejlesen, M. M.

2017-11-01

We present recent developments of the remeshed vortex particle-mesh method for simulating incompressible fluid flow. The presented method relies on a parallel higher-order FFT based solver for the Poisson equation. Arbitrary high order is achieved through regularization of singular Green's function solutions to the Poisson equation and recently we have derived novel high order solutions for a mixture of open and periodic domains. With this approach the simulated variables may formally be viewed as the approximate solution to the filtered Navier Stokes equations, hence we use the method for Large Eddy Simulation by including a dynamic subfilter-scale model based on test-filters compatible with the aforementioned regularization functions. Further the subfilter-scale model uses Lagrangian averaging, which is a natural candidate in light of the Lagrangian nature of vortex particle methods. A multiresolution variation of the method is applied to simulate the benchmark problem of the flow past a square cylinder at Re = 22000 and the obtained results are compared to results from the literature.

Constrained Perturbation Regularization Approach for Signal Estimation Using Random Matrix Theory

KAUST Repository

Suliman, Mohamed Abdalla Elhag

2016-10-06

In this work, we propose a new regularization approach for linear least-squares problems with random matrices. In the proposed constrained perturbation regularization approach, an artificial perturbation matrix with a bounded norm is forced into the system model matrix. This perturbation is introduced to improve the singular-value structure of the model matrix and, hence, the solution of the estimation problem. Relying on the randomness of the model matrix, a number of deterministic equivalents from random matrix theory are applied to derive the near-optimum regularizer that minimizes the mean-squared error of the estimator. Simulation results demonstrate that the proposed approach outperforms a set of benchmark regularization methods for various estimated signal characteristics. In addition, simulations show that our approach is robust in the presence of model uncertainty.

Bovine viral diarrhea virus in free-ranging wild ruminants in Switzerland: low prevalence of infection despite regular interactions with domestic livestock

Science.gov (United States)

2012-01-01

Background In the frame of an eradication program for bovine viral diarrhea (BVD) in Swiss livestock, the question was raised whether free-ranging wildlife could threaten the success of this sanitary measure. Therefore, we conducted serological and virological investigations on BVD virus (BVDV) infections in the four indigenous wild ruminant species (roe deer, red deer, Alpine chamois and Alpine ibex) from 2009 to 2011, and gathered information on interactions between wild and domestic ruminants in an alpine environment by questionnaire survey. Results Thirty-two sera out of 1’877 (1.7%, 95% confidence interval [CI] 1.2-2.4) were seropositive for BVDV, and a BVDV1 sub genotype h virus was found in a seropositive chamois (0.05%, 95% CI 0.001-0.3). The seropositive animals originated from sub-alpine or alpine regions and significantly more seropositive red deer, chamois and ibex than roe deer were found. There were no statistically significant differences between sampling units, age classes, genders, and sampling years. The obtained prevalences were significantly lower than those documented in livestock, and most positive wild ruminants were found in proximity of domestic outbreaks. Additionally, BVDV seroprevalence in ibex was significantly lower than previously reported from Switzerland. The survey on interspecific interactions revealed that interactions expected to allow BVDV transmission, from physical contacts to non-simultaneous use of the same areas, regularly occur on pastures among all investigated ruminant species. Interactions involving cervids were more often observed with cattle than with small ruminants, chamois were observed with all three domestic species, and ibex interacted mostly with small ruminants. Interactions related to the use of anthropogenic food sources were frequently observed, especially between red deer and cattle in wintertime. Conclusions To our knowledge, this is the first report of BVDV RNA isolated from an Alpine chamois

On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

OpenAIRE

John A. D. Appleby

2010-01-01

We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. ...

Regularization methods in Banach spaces

CERN Document Server

Schuster, Thomas; Hofmann, Bernd; Kazimierski, Kamil S

2012-01-01

Regularization methods aimed at finding stable approximate solutions are a necessary tool to tackle inverse and ill-posed problems. Usually the mathematical model of an inverse problem consists of an operator equation of the first kind and often the associated forward operator acts between Hilbert spaces. However, for numerous problems the reasons for using a Hilbert space setting seem to be based rather on conventions than on an approprimate and realistic model choice, so often a Banach space setting would be closer to reality. Furthermore, sparsity constraints using general Lp-norms or the B

Renormalization group equation for interacting Thirring fields in dimensional regularization scheme

International Nuclear Information System (INIS)

Chowdhury, A.R.; Roy, T.; Kar, S.

1976-01-01

The dynamics of two interacting Thirring fields has been investigated within the dimensional regularization framework. The coupling constants are renormalized in the same way as observed in the non-perturbative approach of Ansel'm et al (Sov. Phys. - JETP 36: 608 (1959)). Functionsβsub(i)(g 1 , g 2 , g 3 ) and γsub(i)(g 1 , g 2 , g 3 ), pertaining to the stability and anomalous behaviour of the problem, are computed up to a third order in the coupling parameters. With the help of these, subsidiary non-linear differential equations of the renormalization group are studied in 2-epsilon dimension. The results show up some peculiar features of the theory: a zero of βsub(i)(g 1 , g 2 , g 3 ) corresponding to g 2 approximately α√epsilon, a characteristic of phi theory. The scale invariant limit is reached when g 2 → 0 (i.e. the two Thirring fields are decoupled) and also when g 1 = xg 2 = g 3 , where x is a root of 2x 3 + 2x 2 - 1 = 0. The branch-point zero makes the transition to the epsilon tends to 0 limit non-unique. The anomalous dimensions are obtained and seen to match that of the Dashen-Frishman model (Phys. Lett.; 46B 439 (1973)). The existence of a non-trivial scale invariant limit distinguishes the model from many simple field theories. (author)

Thin accretion disk around regular black hole

Directory of Open Access Journals (Sweden)

QIU Tianqi

2014-08-01

Full Text Available The Penrose′s cosmic censorship conjecture says that naked singularities do not exist in nature.So,it seems reasonable to further conjecture that not even a singularity exists in nature.In this paper,a regular black hole without singularity is studied in detail,especially on its thin accretion disk,energy flux,radiation temperature and accretion efficiency.It is found that the interaction of regular black hole is stronger than that of the Schwarzschild black hole. Furthermore,the thin accretion will be more efficiency to lost energy while the mass of black hole decreased. These particular properties may be used to distinguish between black holes.

Regularity and chaos in cavity QED

International Nuclear Information System (INIS)

Bastarrachea-Magnani, Miguel Angel; López-del-Carpio, Baldemar; Chávez-Carlos, Jorge; Lerma-Hernández, Sergio; Hirsch, Jorge G

2017-01-01

The interaction of a quantized electromagnetic field in a cavity with a set of two-level atoms inside it can be described with algebraic Hamiltonians of increasing complexity, from the Rabi to the Dicke models. Their algebraic character allows, through the use of coherent states, a semiclassical description in phase space, where the non-integrable Dicke model has regions associated with regular and chaotic motion. The appearance of classical chaos can be quantified calculating the largest Lyapunov exponent over the whole available phase space for a given energy. In the quantum regime, employing efficient diagonalization techniques, we are able to perform a detailed quantitative study of the regular and chaotic regions, where the quantum participation ratio (P R ) of coherent states on the eigenenergy basis plays a role equivalent to the Lyapunov exponent. It is noted that, in the thermodynamic limit, dividing the participation ratio by the number of atoms leads to a positive value in chaotic regions, while it tends to zero in the regular ones. (paper)

Interactions of acidic solutions with sediments: a case study

International Nuclear Information System (INIS)

Peterson, S.R.; Serne, R.J.; Felmy, A.R.; Erikson, R.L.; Krupka, K.M.; Gee, G.W.

1984-01-01

A methodology is presented for investigating the chemical interactions of acidic solutions with sediments. The MINTEQ geochemical computer code was used to predict solid-phase reactions that might occur when acidic solutions contact neutral sediments which, in turn, may control the concentrations of certain dissolved components. Results of X-ray diffraction analysis of laboratory samples of sediments that have been contacted with acidic uranium mill tailings solutions suggest gypsum and jarosite precipitated. These same mineralogical changes were identified in sediment samples collected from a drained uranium mill evaporation pond (Lucky Mc mine in Wyoming) with a 10-year history of acid attack. Geochemical modeling predicted that these same phases and several amorphous solids not identifiable by X-ray diffraction should have precipitated in the contacted sediments. An equilibrium conceptual model consisting of an assemblage of minerals and amorphous solid phases was then developed to represent a sediment column through which uranium mill tailings solutions were percolated. The MINTEQ code was used to predict effluent solution concentrations resulting from the reactions of the tailings solution with the assemblage of solid phases in the conceptual model. The conceptual model successfully predicted the concentrations of several of the macro-constituents (e.g., Ca, SO 4 , Al, Fe, and Mn), but was not successful in modeling the concentrations of trace elements. The lack of success in predicting the observed trace metal concentrations suggests that other mechanisms, such as adsorption, must be included in future models. The geochemical modeling methodology coupled with the laboratory and field studies should be applicable to a variety of waste disposal problems

Image deblurring using a perturbation-basec regularization approach

KAUST Repository

Alanazi, Abdulrahman

2017-11-02

The image restoration problem deals with images in which information has been degraded by blur or noise. In this work, we present a new method for image deblurring by solving a regularized linear least-squares problem. In the proposed method, a synthetic perturbation matrix with a bounded norm is forced into the discrete ill-conditioned model matrix. This perturbation is added to enhance the singular-value structure of the matrix and hence to provide an improved solution. A method is proposed to find a near-optimal value of the regularization parameter for the proposed approach. To reduce the computational complexity, we present a technique based on the bootstrapping method to estimate the regularization parameter for both low and high-resolution images. Experimental results on the image deblurring problem are presented. Comparisons are made with three benchmark methods and the results demonstrate that the proposed method clearly outperforms the other methods in terms of both the output PSNR and SSIM values.

Image deblurring using a perturbation-basec regularization approach

KAUST Repository

Alanazi, Abdulrahman; Ballal, Tarig; Masood, Mudassir; Al-Naffouri, Tareq Y.

2017-01-01

The image restoration problem deals with images in which information has been degraded by blur or noise. In this work, we present a new method for image deblurring by solving a regularized linear least-squares problem. In the proposed method, a synthetic perturbation matrix with a bounded norm is forced into the discrete ill-conditioned model matrix. This perturbation is added to enhance the singular-value structure of the matrix and hence to provide an improved solution. A method is proposed to find a near-optimal value of the regularization parameter for the proposed approach. To reduce the computational complexity, we present a technique based on the bootstrapping method to estimate the regularization parameter for both low and high-resolution images. Experimental results on the image deblurring problem are presented. Comparisons are made with three benchmark methods and the results demonstrate that the proposed method clearly outperforms the other methods in terms of both the output PSNR and SSIM values.

Interactive Tutoring in Blended Studies: Hindrances and Solutions

Directory of Open Access Journals (Sweden)

Asim Ismail Ilyas (Al-Titinchy

2016-01-01

Full Text Available This paper distinguishes between traditional teaching known as lecturing (the teacher centered approach; and tutoring (the contemporary technology-oriented interactive teaching/learning approach. It is based on the implementation of tutoring strategies of ‘blended studies’  at the Arab Open University. It investigates the application of modern interactive teaching/learning strategies, specifying some hindering factors in the AOU-Jordan Branch context. The factors include four variables: tutors, students, course material and assessment. The paper is based on qualitative research in terms of a real teaching/leaning context, using both observation and conversation with learners, besides the use of some quantitative data retrieved from a questionnaire in which learners’ views are sought regarding a number of relevant matters. A number of suggested solutions related to each of the hindering factors are presented, which if applied, may secure shifting the balance of the teaching/learning process to a more interactive technology-based tutoring level, which in turn will enhance learners’ opportunities for the attainment of better academic standards, and secure a higher degree of achievement of the shared educational goals of learners and the educational institution they study in.

Proliferating cell nuclear antigen (PCNA interactions in solution studied by NMR.

Directory of Open Access Journals (Sweden)

Alfredo De Biasio

Full Text Available PCNA is an essential factor for DNA replication and repair. It forms a ring shaped structure of 86 kDa by the symmetric association of three identical protomers. The ring encircles the DNA and acts as a docking platform for other proteins, most of them containing the PCNA Interaction Protein sequence (PIP-box. We have used NMR to characterize the interactions of PCNA with several other proteins and fragments in solution. The binding of the PIP-box peptide of the cell cycle inhibitor p21 to PCNA is consistent with the crystal structure of the complex. A shorter p21 peptide binds with reduced affinity but retains most of the molecular recognition determinants. However the binding of the corresponding peptide of the tumor suppressor ING1 is extremely weak, indicating that slight deviations from the consensus PIP-box sequence dramatically reduce the affinity for PCNA, in contrast with a proposed less stringent PIP-box sequence requirement. We could not detect any binding between PCNA and the MCL-1 or the CDK2 protein, reported to interact with PCNA in biochemical assays. This suggests that they do not bind directly to PCNA, or they do but very weakly, with additional unidentified factors stabilizing the interactions in the cell. Backbone dynamics measurements show three PCNA regions with high relative flexibility, including the interdomain connector loop (IDCL and the C-terminus, both of them involved in the interaction with the PIP-box. Our work provides the basis for high resolution studies of direct ligand binding to PCNA in solution.

Molecular-scale hydrophobic interactions between hard-sphere reference solutes are attractive and endothermic.

Science.gov (United States)

Chaudhari, Mangesh I; Holleran, Sinead A; Ashbaugh, Henry S; Pratt, Lawrence R

2013-12-17

The osmotic second virial coefficients, B2, for atomic-sized hard spheres in water are attractive (B2 attractive with increasing temperature (ΔB2/ΔT attractive and endothermic at moderate temperatures. Hydrophobic interactions between atomic-sized hard spheres in water are more attractive than predicted by the available statistical mechanical theory. These results constitute an initial step toward detailed molecular theory of additional intermolecular interaction features, specifically, attractive interactions associated with hydrophobic solutes.

Remarks about singular solutions to the Dirac equation

International Nuclear Information System (INIS)

Uhlir, M.

1975-01-01

In the paper singular solutions of the Dirac equation are investigated. They are derived in the Lorentz-covariant way of functions proportional to static multipole fields of scalar and (or) electromagnetic fields and of regular solutions of the Dirac equations. The regularization procedure excluding divergences of total energy, momentum and angular momentum of the spinor field considered is proposed

Free-solution, label-free molecular interactions studied by back-scattering interferometry

DEFF Research Database (Denmark)

Bornhop, D.J.; Latham, J.C.; Kussrow, A.

2007-01-01

Free-solution, label-free molecular interactions were investigated with back-scattering interferometry in a simple optical train composed of a helium-neon laser, a microfluidic channel, and a position sensor. Molecular binding interactions between proteins, ions and protein, and small molecules...... and protein, were determined with high dynamic range dissociation constants (K-d spanning six decades) and unmatched sensitivity (picomolar K-d's and detection limits of 10,000s of molecules). With this technique, equilibrium dissociation constants were quantified for protein A and immunoglobulin G...

Interaction of cadmium and indium nitrate mixture with sodium tungstate in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Belousova, E E; Krivobok, V I; Gruba, A I [Donetskij Gosudarstvennyj Univ. (Ukrainian SSR)

1982-01-01

The interaction of the mixture of cadmium and indium nitrates with sodium tungstate in aqueous solution is studied using the methods of ''residual concentrations'', pH potentiometry and conductometry. Independent of the ratio of components in the initial solution a mixture of coprecipitated normal tungstates of cadmium and indium is formed in the system. Heat treatment of the precipitates at 800 deg C for 50 hrs with subsequent hardening results in the formation of solid solutions on the basis of normal cadmium and indium tungstates.

Fast regularizing sequential subspace optimization in Banach spaces

International Nuclear Information System (INIS)

Schöpfer, F; Schuster, T

2009-01-01

We are concerned with fast computations of regularized solutions of linear operator equations in Banach spaces in case only noisy data are available. To this end we modify recently developed sequential subspace optimization methods in such a way that the therein employed Bregman projections onto hyperplanes are replaced by Bregman projections onto stripes whose width is in the order of the noise level

Sparse reconstruction by means of the standard Tikhonov regularization

International Nuclear Information System (INIS)

Lu Shuai; Pereverzev, Sergei V

2008-01-01

It is a common belief that Tikhonov scheme with || · ||L 2 -penalty fails in sparse reconstruction. We are going to show, however, that this standard regularization can help if the stability measured in L 1 -norm will be properly taken into account in the choice of the regularization parameter. The crucial point is that now a stability bound may depend on the bases with respect to which the solution of the problem is assumed to be sparse. We discuss how such a stability can be estimated numerically and present the results of computational experiments giving the evidence of the reliability of our approach.

Monopole Solutions in Topologically Massive Gauge Theory

International Nuclear Information System (INIS)

Teh, Rosy; Wong, Khai-Ming; Koh, Pin-Wai

2010-01-01

Monopoles in topologically massive SU(2) Yang-Mils-Higgs gauge theory in 2+1 dimensions with a Chern-Simon mass term have been studied by Pisarski some years ago. He argued that there is a monopole solution that is regular everywhere, but found that it does not possess finite action. There were no exact or numerical solutions being presented by him. Hence it is our purpose to further investigate this solution in more detail. We obtained numerical regular solutions that smoothly interpolates between the behavior at small and large distances for different values of Chern-Simon term strength and for several fixed values of Higgs field strength.

Supporting Regularized Logistic Regression Privately and Efficiently

Science.gov (United States)

Li, Wenfa; Liu, Hongzhe; Yang, Peng; Xie, Wei

2016-01-01

As one of the most popular statistical and machine learning models, logistic regression with regularization has found wide adoption in biomedicine, social sciences, information technology, and so on. These domains often involve data of human subjects that are contingent upon strict privacy regulations. Concerns over data privacy make it increasingly difficult to coordinate and conduct large-scale collaborative studies, which typically rely on cross-institution data sharing and joint analysis. Our work here focuses on safeguarding regularized logistic regression, a widely-used statistical model while at the same time has not been investigated from a data security and privacy perspective. We consider a common use scenario of multi-institution collaborative studies, such as in the form of research consortia or networks as widely seen in genetics, epidemiology, social sciences, etc. To make our privacy-enhancing solution practical, we demonstrate a non-conventional and computationally efficient method leveraging distributing computing and strong cryptography to provide comprehensive protection over individual-level and summary data. Extensive empirical evaluations on several studies validate the privacy guarantee, efficiency and scalability of our proposal. We also discuss the practical implications of our solution for large-scale studies and applications from various disciplines, including genetic and biomedical studies, smart grid, network analysis, etc. PMID:27271738

Supporting Regularized Logistic Regression Privately and Efficiently.

Science.gov (United States)

Li, Wenfa; Liu, Hongzhe; Yang, Peng; Xie, Wei

2016-01-01

As one of the most popular statistical and machine learning models, logistic regression with regularization has found wide adoption in biomedicine, social sciences, information technology, and so on. These domains often involve data of human subjects that are contingent upon strict privacy regulations. Concerns over data privacy make it increasingly difficult to coordinate and conduct large-scale collaborative studies, which typically rely on cross-institution data sharing and joint analysis. Our work here focuses on safeguarding regularized logistic regression, a widely-used statistical model while at the same time has not been investigated from a data security and privacy perspective. We consider a common use scenario of multi-institution collaborative studies, such as in the form of research consortia or networks as widely seen in genetics, epidemiology, social sciences, etc. To make our privacy-enhancing solution practical, we demonstrate a non-conventional and computationally efficient method leveraging distributing computing and strong cryptography to provide comprehensive protection over individual-level and summary data. Extensive empirical evaluations on several studies validate the privacy guarantee, efficiency and scalability of our proposal. We also discuss the practical implications of our solution for large-scale studies and applications from various disciplines, including genetic and biomedical studies, smart grid, network analysis, etc.

Supporting Regularized Logistic Regression Privately and Efficiently.

Directory of Open Access Journals (Sweden)

Wenfa Li

Full Text Available As one of the most popular statistical and machine learning models, logistic regression with regularization has found wide adoption in biomedicine, social sciences, information technology, and so on. These domains often involve data of human subjects that are contingent upon strict privacy regulations. Concerns over data privacy make it increasingly difficult to coordinate and conduct large-scale collaborative studies, which typically rely on cross-institution data sharing and joint analysis. Our work here focuses on safeguarding regularized logistic regression, a widely-used statistical model while at the same time has not been investigated from a data security and privacy perspective. We consider a common use scenario of multi-institution collaborative studies, such as in the form of research consortia or networks as widely seen in genetics, epidemiology, social sciences, etc. To make our privacy-enhancing solution practical, we demonstrate a non-conventional and computationally efficient method leveraging distributing computing and strong cryptography to provide comprehensive protection over individual-level and summary data. Extensive empirical evaluations on several studies validate the privacy guarantee, efficiency and scalability of our proposal. We also discuss the practical implications of our solution for large-scale studies and applications from various disciplines, including genetic and biomedical studies, smart grid, network analysis, etc.

Linear operator inequalities for strongly stable weakly regular linear systems

NARCIS (Netherlands)

Curtain, RF

2001-01-01

We consider the question of the existence of solutions to certain linear operator inequalities (Lur'e equations) for strongly stable, weakly regular linear systems with generating operators A, B, C, 0. These operator inequalities are related to the spectral factorization of an associated Popov

Variational regularization of 3D data experiments with Matlab

CERN Document Server

Montegranario, Hebert

2014-01-01

Variational Regularization of 3D Data provides an introduction to variational methods for data modelling and its application in computer vision. In this book, the authors identify interpolation as an inverse problem that can be solved by Tikhonov regularization. The proposed solutions are generalizations of one-dimensional splines, applicable to n-dimensional data and the central idea is that these splines can be obtained by regularization theory using a trade-off between the fidelity of the data and smoothness properties.As a foundation, the authors present a comprehensive guide to the necessary fundamentals of functional analysis and variational calculus, as well as splines. The implementation and numerical experiments are illustrated using MATLAB®. The book also includes the necessary theoretical background for approximation methods and some details of the computer implementation of the algorithms. A working knowledge of multivariable calculus and basic vector and matrix methods should serve as an adequat...

A regularized vortex-particle mesh method for large eddy simulation

DEFF Research Database (Denmark)

Spietz, Henrik Juul; Walther, Jens Honore; Hejlesen, Mads Mølholm

We present recent developments of the remeshed vortex particle-mesh method for simulating incompressible fluid flow. The presented method relies on a parallel higher-order FFT based solver for the Poisson equation. Arbitrary high order is achieved through regularization of singular Green’s function...... solutions to the Poisson equation and recently we have derived novel high order solutions for a mixture of open and periodic domains. With this approach the simulated variables may formally be viewed as the approximate solution to the filtered Navier Stokes equations, hence we use the method for Large Eddy...

Sound Attenuation in Elliptic Mufflers Using a Regular Perturbation Method

OpenAIRE

Banerjee, Subhabrata; Jacobi, Anthony M.

2012-01-01

The study of sound attenuation in an elliptical chamber involves the solution of the Helmholtz equation in elliptic coordinate systems. The Eigen solutions for such problems involve the Mathieu and the modified Mathieu functions. The computation of such functions poses considerable challenge. An alternative method to solve such problems had been proposed in this paper. The elliptical cross-section of the muffler has been treated as a perturbed circle, enabling the use of a regular perturbatio...

Interactions of dipeptides with Triton X-100 in aqueous solution: A volumetric and spectroscopic study

International Nuclear Information System (INIS)

Yan, Zhenning; Wu, Shuangyan; Pan, Qi; Geng, Rui; Gu, Bixin; Wang, Jianji

2014-01-01

Highlights: • The values of V 2,ϕ o and Δ t V° are positive. • Interactions of Triton X-100 with charged and polar groups of dipeptides dominate. • Addition of dipeptide in water decreases the c cmc and the aggregation number of Triton X-100. • The affinity between dipeptide and Triton X-100 micelle increases with the increase in the length of alkyl chain of peptides. • Triton X-100 interacts with dipeptides more weakly than SDS. -- Abstract: The interactions of dipeptides with Triton X-100 in aqueous solution have been investigated by means of density, fluorescence spectroscopy and UV–vis spectroscopy. The standard partial molar volume (V 2,ϕ o ), standard partial molar volume of transfer for dipeptide from water to aqueous Triton X-100 solution (Δ t V o ) and partial molar expansibility (E ϕ o ) have been calculated from density data. Fluorescence spectroscopy was used to estimate the critical micellar concentration (c cmc ) and micelle aggregation number of Triton X-100 in aqueous dipeptide solutions. Effects of temperature and hydrocarbon chain length of dipeptides on the volumetric properties of dipeptide and critical micelle concentration (c cmc ) of Triton X-100 were examined. The pyrene fluorescence spectra were also used to study the change of micropolarity produced by the interactions of Triton X-100 with dipeptides. From the results of UV–vis absorption spectra, the binding constant between dipeptide and Triton X-100 above the c cmc was determined. The results have been interpreted in terms of solute–solvent interactions and structural changes in the mixed solutions

Analysis of regularized inversion of data corrupted by white Gaussian noise

International Nuclear Information System (INIS)

Kekkonen, Hanne; Lassas, Matti; Siltanen, Samuli

2014-01-01

Tikhonov regularization is studied in the case of linear pseudodifferential operator as the forward map and additive white Gaussian noise as the measurement error. The measurement model for an unknown function u(x) is m(x) = Au(x) + δ ε (x), where δ > 0 is the noise magnitude. If ε was an L 2 -function, Tikhonov regularization gives an estimate T α (m) = u∈H r arg min { ||Au-m|| L 2 2 + α||u|| H r 2 } for u where α = α(δ) is the regularization parameter. Here penalization of the Sobolev norm ||u|| H r covers the cases of standard Tikhonov regularization (r = 0) and first derivative penalty (r = 1). Realizations of white Gaussian noise are almost never in L 2 , but do belong to H s with probability one if s < 0 is small enough. A modification of Tikhonov regularization theory is presented, covering the case of white Gaussian measurement noise. Furthermore, the convergence of regularized reconstructions to the correct solution as δ → 0 is proven in appropriate function spaces using microlocal analysis. The convergence of the related finite-dimensional problems to the infinite-dimensional problem is also analysed. (paper)

On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

Directory of Open Access Journals (Sweden)

Appleby JohnAD

2010-01-01

Full Text Available We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. The result is considered both for a linear Volterra integrodifferential equation as well as for the delay logistic equation from population biology.

Formation of Robust Multi-Agent Networks through Self-Organizing Random Regular Graphs

KAUST Repository

Yasin Yazicioǧlu, A.; Egerstedt, Magnus; Shamma, Jeff S.

2015-01-01

Multi-Agent networks are often modeled as interaction graphs, where the nodes represent the agents and the edges denote some direct interactions. The robustness of a multi-Agent network to perturbations such as failures, noise, or malicious attacks largely depends on the corresponding graph. In many applications, networks are desired to have well-connected interaction graphs with relatively small number of links. One family of such graphs is the random regular graphs. In this paper, we present a decentralized scheme for transforming any connected interaction graph with a possibly non-integer average degree of k into a connected random m-regular graph for some m ϵ [k+k ] 2. Accordingly, the agents improve the robustness of the network while maintaining a similar number of links as the initial configuration by locally adding or removing some edges. © 2015 IEEE.

Formation of Robust Multi-Agent Networks through Self-Organizing Random Regular Graphs

KAUST Repository

Yasin Yazicioǧlu, A.

2015-11-25

Multi-Agent networks are often modeled as interaction graphs, where the nodes represent the agents and the edges denote some direct interactions. The robustness of a multi-Agent network to perturbations such as failures, noise, or malicious attacks largely depends on the corresponding graph. In many applications, networks are desired to have well-connected interaction graphs with relatively small number of links. One family of such graphs is the random regular graphs. In this paper, we present a decentralized scheme for transforming any connected interaction graph with a possibly non-integer average degree of k into a connected random m-regular graph for some m ϵ [k+k ] 2. Accordingly, the agents improve the robustness of the network while maintaining a similar number of links as the initial configuration by locally adding or removing some edges. © 2015 IEEE.

Poisson image reconstruction with Hessian Schatten-norm regularization.

Science.gov (United States)

Lefkimmiatis, Stamatios; Unser, Michael

2013-11-01

Poisson inverse problems arise in many modern imaging applications, including biomedical and astronomical ones. The main challenge is to obtain an estimate of the underlying image from a set of measurements degraded by a linear operator and further corrupted by Poisson noise. In this paper, we propose an efficient framework for Poisson image reconstruction, under a regularization approach, which depends on matrix-valued regularization operators. In particular, the employed regularizers involve the Hessian as the regularization operator and Schatten matrix norms as the potential functions. For the solution of the problem, we propose two optimization algorithms that are specifically tailored to the Poisson nature of the noise. These algorithms are based on an augmented-Lagrangian formulation of the problem and correspond to two variants of the alternating direction method of multipliers. Further, we derive a link that relates the proximal map of an l(p) norm with the proximal map of a Schatten matrix norm of order p. This link plays a key role in the development of one of the proposed algorithms. Finally, we provide experimental results on natural and biological images for the task of Poisson image deblurring and demonstrate the practical relevance and effectiveness of the proposed framework.

Wave, particle-family duality and the conservation of discrete symmetries in strong interaction

International Nuclear Information System (INIS)

van der Spuy, E.

1984-01-01

This paper starts from a nonlinear fermion field equation of motion with a strongly coupled self-interaction. Nonperturbative quark solutions of the equation of motion are constructed in terms of a Reggeized infinite component free spinor field. Such a field carries a family of strongly interacting unstable compounds lying on a Regge locus in the analytically continued quark spin. Such a quark field is naturally confined and also possesses the property of asymptotic freedom. Furthermore, the particular field self-regularizes the interactions and naturally breaks the chiral invariance of the equation of motion. We show why and how the existence of such a strongly coupled solution and its particle-family, wave duality forces a change in the field equation of motion such that it conserves C,P,T, although its individual interaction terms are of V-A and thus C,P nonconserving type

Measuring the enthalpies of interaction between glycine, L-cysteine, glycylglycine, and sodium dodecyl sulfate in aqueous solutions

Science.gov (United States)

Badelin, V. G.; Mezhevoi, I. N.; Tyunina, E. Yu.

2017-03-01

Calorimetric measurements of enthalpies of solution Δsol H m for glycine, L-cysteine, and glycylglycine in aqueous solutions of sodium dodecyl sulfate (SDS) with concentrations of up to 0.05 mol kg-1 are made. Standard enthalpy of solution Δsol H 0 and enthalpy of transfer Δtr H 0 of the dipeptide from water into mixed solvent are calculated. The calculated enthalpy coefficients of paired interactions of amino acids and dipeptide with SDS prove to be positive. Hydrophobic interactions between the biomolecules and SDS are found to have a major impact on the enthalpies of interaction in the three-component systems under study, within the indicated range of concentrations.

A Priori Regularity of Parabolic Partial Differential Equations

KAUST Repository

Berkemeier, Francisco

2018-05-13

In this thesis, we consider parabolic partial differential equations such as the heat equation, the Fokker-Planck equation, and the porous media equation. Our aim is to develop methods that provide a priori estimates for solutions with singular initial data. These estimates are obtained by understanding the time decay of norms of solutions. First, we derive regularity results for the heat equation by estimating the decay of Lebesgue norms. Then, we apply similar methods to the Fokker-Planck equation with suitable assumptions on the advection and diffusion. Finally, we conclude by extending our techniques to the porous media equation. The sharpness of our results is confirmed by examining known solutions of these equations. The main contribution of this thesis is the use of functional inequalities to express decay of norms as differential inequalities. These are then combined with ODE methods to deduce estimates for the norms of solutions and their derivatives.

Novel Harmonic Regularization Approach for Variable Selection in Cox’s Proportional Hazards Model

Directory of Open Access Journals (Sweden)

Ge-Jin Chu

2014-01-01

Full Text Available Variable selection is an important issue in regression and a number of variable selection methods have been proposed involving nonconvex penalty functions. In this paper, we investigate a novel harmonic regularization method, which can approximate nonconvex Lq  (1/2regularizations, to select key risk factors in the Cox’s proportional hazards model using microarray gene expression data. The harmonic regularization method can be efficiently solved using our proposed direct path seeking approach, which can produce solutions that closely approximate those for the convex loss function and the nonconvex regularization. Simulation results based on the artificial datasets and four real microarray gene expression datasets, such as real diffuse large B-cell lymphoma (DCBCL, the lung cancer, and the AML datasets, show that the harmonic regularization method can be more accurate for variable selection than existing Lasso series methods.

Manifold optimization-based analysis dictionary learning with an ℓ1∕2-norm regularizer.

Science.gov (United States)

Li, Zhenni; Ding, Shuxue; Li, Yujie; Yang, Zuyuan; Xie, Shengli; Chen, Wuhui

2018-02-01

Recently there has been increasing attention towards analysis dictionary learning. In analysis dictionary learning, it is an open problem to obtain the strong sparsity-promoting solutions efficiently while simultaneously avoiding the trivial solutions of the dictionary. In this paper, to obtain the strong sparsity-promoting solutions, we employ the ℓ 1∕2 norm as a regularizer. The very recent study on ℓ 1∕2 norm regularization theory in compressive sensing shows that its solutions can give sparser results than using the ℓ 1 norm. We transform a complex nonconvex optimization into a number of one-dimensional minimization problems. Then the closed-form solutions can be obtained efficiently. To avoid trivial solutions, we apply manifold optimization to update the dictionary directly on the manifold satisfying the orthonormality constraint, so that the dictionary can avoid the trivial solutions well while simultaneously capturing the intrinsic properties of the dictionary. The experiments with synthetic and real-world data verify that the proposed algorithm for analysis dictionary learning can not only obtain strong sparsity-promoting solutions efficiently, but also learn more accurate dictionary in terms of dictionary recovery and image processing than the state-of-the-art algorithms. Copyright © 2017 Elsevier Ltd. All rights reserved.

A regularity criterion for the Navier-Stokes equations based on the gradient of one velocity component

Czech Academy of Sciences Publication Activity Database

Skalák, Zdeněk

2016-01-01

Roč. 437, č. 1 (2016), s. 474-484 ISSN 0022-247X R&D Projects: GA ČR GA14-02067S Institutional support: RVO:67985874 Keywords : Navier - Stokes equations * regularity of solutions * regularity criteria Subject RIV: BK - Fluid Dynamics Impact factor: 1.064, year: 2016

Phase reconstruction by a multilevel iteratively regularized Gauss–Newton method

International Nuclear Information System (INIS)

Langemann, Dirk; Tasche, Manfred

2008-01-01

In this paper we consider the numerical solution of a phase retrieval problem for a compactly supported, linear spline f : R → C with the Fourier transform f-circumflex, where values of |f| and |f-circumflex| at finitely many equispaced nodes are given. The unknown phases of complex spline coefficients fulfil a well-structured system of nonlinear equations. Thus the phase reconstruction leads to a nonlinear inverse problem, which is solved by a multilevel strategy and iterative Tikhonov regularization. The multilevel strategy concentrates the main effort of the solution of the phase retrieval problem in the coarse, less expensive levels and provides convenient initial guesses at the next finer level. On each level, the corresponding nonlinear system is solved by an iteratively regularized Gauss–Newton method. The multilevel strategy is motivated by convergence results of IRGN. This method is applicable to a wide range of examples as shown in several numerical tests for noiseless and noisy data

Regularization algorithm within two-parameters for identification heat-coefficient in the parabolic equation

International Nuclear Information System (INIS)

Hinestroza Gutierrez, D.

2006-08-01

In this work a new and promising algorithm based on the minimization of especial functional that depends on two regularization parameters is considered for the identification of the heat conduction coefficient in the parabolic equation. This algorithm uses the adjoint and sensibility equations. One of the regularization parameters is associated with the heat-coefficient (as in conventional Tikhonov algorithms) but the other is associated with the calculated solution. (author)

Regularization algorithm within two-parameters for identification heat-coefficient in the parabolic equation

International Nuclear Information System (INIS)

Hinestroza Gutierrez, D.

2006-12-01

In this work a new and promising algorithm based in the minimization of especial functional that depends on two regularization parameters is considered for identification of the heat conduction coefficient in the parabolic equation. This algorithm uses the adjoint and sensibility equations. One of the regularization parameters is associated with the heat-coefficient (as in conventional Tikhonov algorithms) but the other is associated with the calculated solution. (author)

Regularity criterion for solutions of the three-dimensional Cahn-Hilliard-Navier-Stokes equations and associated computations.

Science.gov (United States)

Gibbon, John D; Pal, Nairita; Gupta, Anupam; Pandit, Rahul

2016-12-01

We consider the three-dimensional (3D) Cahn-Hilliard equations coupled to, and driven by, the forced, incompressible 3D Navier-Stokes equations. The combination, known as the Cahn-Hilliard-Navier-Stokes (CHNS) equations, is used in statistical mechanics to model the motion of a binary fluid. The potential development of singularities (blow-up) in the contours of the order parameter ϕ is an open problem. To address this we have proved a theorem that closely mimics the Beale-Kato-Majda theorem for the 3D incompressible Euler equations [J. T. Beale, T. Kato, and A. J. Majda, Commun. Math. Phys. 94, 61 (1984)CMPHAY0010-361610.1007/BF01212349]. By taking an L^{∞} norm of the energy of the full binary system, designated as E_{∞}, we have shown that ∫_{0}^{t}E_{∞}(τ)dτ governs the regularity of solutions of the full 3D system. Our direct numerical simulations (DNSs) of the 3D CHNS equations for (a) a gravity-driven Rayleigh Taylor instability and (b) a constant-energy-injection forcing, with 128^{3} to 512^{3} collocation points and over the duration of our DNSs confirm that E_{∞} remains bounded as far as our computations allow.

On the MSE Performance and Optimization of Regularized Problems

KAUST Repository

Alrashdi, Ayed

2016-11-01

The amount of data that has been measured, transmitted/received, and stored in the recent years has dramatically increased. So, today, we are in the world of big data. Fortunately, in many applications, we can take advantages of possible structures and patterns in the data to overcome the curse of dimensionality. The most well known structures include sparsity, low-rankness, block sparsity. This includes a wide range of applications such as machine learning, medical imaging, signal processing, social networks and computer vision. This also led to a specific interest in recovering signals from noisy compressed measurements (Compressed Sensing (CS) problem). Such problems are generally ill-posed unless the signal is structured. The structure can be captured by a regularizer function. This gives rise to a potential interest in regularized inverse problems, where the process of reconstructing the structured signal can be modeled as a regularized problem. This thesis particularly focuses on finding the optimal regularization parameter for such problems, such as ridge regression, LASSO, square-root LASSO and low-rank Generalized LASSO. Our goal is to optimally tune the regularizer to minimize the mean-squared error (MSE) of the solution when the noise variance or structure parameters are unknown. The analysis is based on the framework of the Convex Gaussian Min-max Theorem (CGMT) that has been used recently to precisely predict performance errors.

Application of Littlewood-Paley decomposition to the regularity of Boltzmann type kinetic equations

International Nuclear Information System (INIS)

EL Safadi, M.

2007-03-01

We study the regularity of kinetic equations of Boltzmann type.We use essentially Littlewood-Paley method from harmonic analysis, consisting mainly in working with dyadics annulus. We shall mainly concern with the homogeneous case, where the solution f(t,x,v) depends only on the time t and on the velocities v, while working with realistic and singular cross-sections (non cutoff). In the first part, we study the particular case of Maxwellian molecules. Under this hypothesis, the structure of the Boltzmann operator and his Fourier transform write in a simple form. We show a global C ∞ regularity. Then, we deal with the case of general cross-sections with 'hard potential'. We are interested in the Landau equation which is limit equation to the Boltzmann equation, taking in account grazing collisions. We prove that any weak solution belongs to Schwartz space S. We demonstrate also a similar regularity for the case of Boltzmann equation. Let us note that our method applies directly for all dimensions, and proofs are often simpler compared to other previous ones. Finally, we finish with Boltzmann-Dirac equation. In particular, we adapt the result of regularity obtained in Alexandre, Desvillettes, Wennberg and Villani work, using the dissipation rate connected with Boltzmann-Dirac equation. (author)

Numerical simulation of the regularized long wave equation by He's homotopy perturbation method

International Nuclear Information System (INIS)

Inc, Mustafa; Ugurlu, Yavuz

2007-01-01

In this Letter, we present the homotopy perturbation method (shortly HPM) for obtaining the numerical solution of the RLW equation. We obtain the exact and numerical solutions of the Regularized Long Wave (RLW) equation for certain initial condition. The initial approximation can be freely chosen with possible unknown constants which can be determined by imposing the boundary and initial conditions. Comparison of the results with those of other methods have led us to significant consequences. The numerical solutions are compared with the known analytical solutions

An exact solution of three interacting friendly walks in the bulk

International Nuclear Information System (INIS)

Tabbara, R; Owczarek, A L; Rechnitzer, A

2016-01-01

We find the exact solution of three interacting friendly directed walks on the square lattice in the bulk, modelling a system of homopolymers that can undergo a multiple polymer fusion or zipping transition by introducing two distinct interaction parameters that differentiate between the zipping of only two or all three walks. We establish functional equations for the model’s corresponding generating function that are subsequently solved exactly by means of the obstinate kernel method. We then proceed to analyse our model, first considering the case where triple-walk interaction effects are ignored, finding that our model exhibits two phases which we classify as free and gelated (or zipped) regions, with the system exhibiting a second-order phase transition. We then analyse the full model where both interaction parameters are incorporated, presenting the full phase diagram and highlighting the additional existence of a first-order gelation (zipping) boundary. (paper)

Quasilocal energy, Komar charge and horizon for regular black holes

International Nuclear Information System (INIS)

Balart, Leonardo

2010-01-01

We study the Brown-York quasilocal energy for regular black holes. We also express the identity that relates the difference of the Brown-York quasilocal energy and the Komar charge at the horizon to the total energy of the spacetime for static and spherically symmetric black hole solutions in a convenient way which permits us to understand why this identity is not satisfied when we consider nonlinear electrodynamics. However, we give a relation between quantities evaluated at the horizon and at infinity when nonlinear electrodynamics is considered. Similar relations are obtained for more general static and spherically symmetric black hole solutions which include solutions of dilaton gravity theories.

Least square regularized regression in sum space.

Science.gov (United States)

Xu, Yong-Li; Chen, Di-Rong; Li, Han-Xiong; Liu, Lu

2013-04-01

This paper proposes a least square regularized regression algorithm in sum space of reproducing kernel Hilbert spaces (RKHSs) for nonflat function approximation, and obtains the solution of the algorithm by solving a system of linear equations. This algorithm can approximate the low- and high-frequency component of the target function with large and small scale kernels, respectively. The convergence and learning rate are analyzed. We measure the complexity of the sum space by its covering number and demonstrate that the covering number can be bounded by the product of the covering numbers of basic RKHSs. For sum space of RKHSs with Gaussian kernels, by choosing appropriate parameters, we tradeoff the sample error and regularization error, and obtain a polynomial learning rate, which is better than that in any single RKHS. The utility of this method is illustrated with two simulated data sets and five real-life databases.

Electrostatic interactions in aqueous solutions of polyelectrolyte

International Nuclear Information System (INIS)

Belloni, Luc

1982-01-01

In this study, the structure, equilibrium and transport properties of poly-electrolytes solutions are reported. These dissymmetric systems are studied in the context of a primitive model (Charged hard spheres and rods in a solvent continuum). The first phenomenon studied is the strong electrostatic attractive interaction of counterions on the poly-ion surface. The model used considers the poly-ions on a matrix and the different concentrations are calculated using the P.B. equation. Auto-diffusion coefficients obtained give a good description of experimental slowing down of the counterions. The model allows a correlation between the theoretical limits represented by Bjerrum's and Manning's models and gives a physical significance to the concept of condensation. In the second part, the complete structure is calculated using only slightly restrictive H.N.C. approximation. This theory enables all the pair correlation functions to be calculated as well as thermodynamic data and structure factors. The last part of this study treats transport phenomena. Quasi-elastic light scattering gives information on the autocorrelation function of the scattered light intensity. Analysis using cumulants leads to an effective diffusion coefficient which is theoretically related to the structure factor and the hydrodynamic interactions. A crude approximation of the last contribution allows to fit the experimental data. (author) [fr

Manifestly scale-invariant regularization and quantum effective operators

CERN Document Server

Ghilencea, D.M.

2016-01-01

Scale invariant theories are often used to address the hierarchy problem, however the regularization of their quantum corrections introduces a dimensionful coupling (dimensional regularization) or scale (Pauli-Villars, etc) which break this symmetry explicitly. We show how to avoid this problem and study the implications of a manifestly scale invariant regularization in (classical) scale invariant theories. We use a dilaton-dependent subtraction function $\\mu(\\sigma)$ which after spontaneous breaking of scale symmetry generates the usual DR subtraction scale $\\mu(\\langle\\sigma\\rangle)$. One consequence is that "evanescent" interactions generated by scale invariance of the action in $d=4-2\\epsilon$ (but vanishing in $d=4$), give rise to new, finite quantum corrections. We find a (finite) correction $\\Delta U(\\phi,\\sigma)$ to the one-loop scalar potential for $\\phi$ and $\\sigma$, beyond the Coleman-Weinberg term. $\\Delta U$ is due to an evanescent correction ($\\propto\\epsilon$) to the field-dependent masses (of...

Main regularities of radiolytic transformations of bifunctional organic compounds

International Nuclear Information System (INIS)

Petryaev, E.P.; Shadyro, O.I.

1985-01-01

General regularities of the radiolysis of bifunctional organic compounds (α-diols, ethers of α-diols, amino alcohols, hydroxy aldehydes and hydroxy asids) in aqueous solutions from the early stages of the process to formation of finite products are traced. It is pointed out that the most characteristic course of radiation-chemical, transformation of bifunctional compounds in agueous solutions in the fragmentation process with monomolecular decomposition of primary radicals of initial substrances and simultaneous scission of two vicinal in respect to radical centre bonds via five-membered cyclic transient state. The data obtained are of importance for molecular radiobiology

Existence of weak solutions to first-order stationary mean-field games with Dirichlet conditions

KAUST Repository

Ferreira, Rita; Gomes, Diogo A.; Tada, Teruo

2018-01-01

In this paper, we study first-order stationary monotone mean-field games (MFGs) with Dirichlet boundary conditions. While for Hamilton--Jacobi equations Dirichlet conditions may not be satisfied, here, we establish the existence of solutions of MFGs that satisfy those conditions. To construct these solutions, we introduce a monotone regularized problem. Applying Schaefer's fixed-point theorem and using the monotonicity of the MFG, we verify that there exists a unique weak solution to the regularized problem. Finally, we take the limit of the solutions of the regularized problem and using Minty's method, we show the existence of weak solutions to the original MFG.

Regularized integrable version of the one-dimensional quantum sine-Gordon model

International Nuclear Information System (INIS)

Japaridze, G.I.; Nersesyan, A.A.; Wiegmann, P.B.

1983-01-01

The authors derive a regularized exactly solvable version of the one-dimensional quantum sine-Gordon model proceeding from the exact solution of the U(1)-symmetric Thirring model. The ground state and the excitation spectrum are obtained in the region ν 2 < 8π. (Auth.)

Distance-regular graphs

NARCIS (Netherlands)

van Dam, Edwin R.; Koolen, Jack H.; Tanaka, Hajime

2016-01-01

This is a survey of distance-regular graphs. We present an introduction to distance-regular graphs for the reader who is unfamiliar with the subject, and then give an overview of some developments in the area of distance-regular graphs since the monograph 'BCN'[Brouwer, A.E., Cohen, A.M., Neumaier,

Solution interactions of diclofenac sodium and meclofenamic acid sodium with hydroxypropyl methylcellulose (HPMC).

Science.gov (United States)

Pygall, Samuel R; Griffiths, Peter C; Wolf, Bettina; Timmins, Peter; Melia, Colin D

2011-02-28

Many pharmaceutical agents require formulation in order to facilitate their efficacious delivery. However, the interaction between the active species and the formulation additives has the potential to significantly influence the pharmocokinetics of the active. In this study, the solution interactions between hydroxypropyl methylcellulose (HPMC) with two non-steroidal anti-inflammatories - the sodium salts of diclofenac and meclofenamate - were investigated using tensiometric, rheological, NMR, neutron scattering and turbidimetric techniques. The two drugs behaved very differently-meclofenamate addition to HPMC solutions led to substantial increases in viscosity, a depression of the gel point and a marked reduction in the self-diffusion coefficient of the drug, whereas diclofenac did not induce these changes. Collectively, these observations are evidence of meclofenamate forming self-assembled aggregates on the HPMC, a phenomenon not observed with diclofenac Na. Any process that leads to aggregation on a nonionic polymer will not be strongly favoured when the aggregating species is charged. Thus, it is hypothesised that the distinction between the two drugs arises as a consequence of the tautomerism present in meclofenamate that builds electron density on the carbonyl group that is further stabilised by hydrogen bonding to the HPMC. This mechanism is absent in the diclofenac case and thus no interaction is observed. These studies propose for the first time a molecular basis for the observed often-unexpected, concentration-dependant changes in HPMC solution properties when co-formulated with different NSAIDs, and underline the importance of characterising such fundamental interactions that have the potential to influence drug release in solid HPMC-based dosage forms. Copyright © 2010 Elsevier B.V. All rights reserved.

Enthalpic interactions of N-glycylglycine with xylitol in aqueous sodium chloride and potassium chloride solutions at T = 298.15 K

International Nuclear Information System (INIS)

Liu Min; Wang Lili; Zhu Lanying; Li Hui; Sun Dezhi; Di Youying; Li Linwei

2010-01-01

The mixing enthalpies of N-glycylglycine with xylitol and their respective enthalpies of dilution in aqueous sodium chloride and potassium chloride solutions have been determined by using flow-mix isothermal microcalorimetry at the temperature of 298.15 K. These experimental results have been used to determine the heterotactic enthalpic interaction coefficients (h xy , h xxy , and h xyy ) according to the McMillan-Mayer theory. It has been found that the heterotactic enthalpic pairwise interaction coefficients h xy between N-glycylglycine and xylitol in aqueous sodium chloride and potassium chloride solutions are negative and become less negative with an increase in the molality of sodium chloride or potassium chloride. The results are discussed in terms of solute-solute and solute-solvent interactions.

Enthalpic interactions of N-glycylglycine with xylitol in aqueous sodium chloride and potassium chloride solutions at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Liu Min, E-mail: panpanliumin@163.co [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Wang Lili [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Zhu Lanying [College of Life Science and Bioengineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Li Hui; Sun Dezhi; Di Youying; Li Linwei [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China)

2010-07-15

The mixing enthalpies of N-glycylglycine with xylitol and their respective enthalpies of dilution in aqueous sodium chloride and potassium chloride solutions have been determined by using flow-mix isothermal microcalorimetry at the temperature of 298.15 K. These experimental results have been used to determine the heterotactic enthalpic interaction coefficients (h{sub xy}, h{sub xxy}, and h{sub xyy}) according to the McMillan-Mayer theory. It has been found that the heterotactic enthalpic pairwise interaction coefficients h{sub xy} between N-glycylglycine and xylitol in aqueous sodium chloride and potassium chloride solutions are negative and become less negative with an increase in the molality of sodium chloride or potassium chloride. The results are discussed in terms of solute-solute and solute-solvent interactions.

Regularity for 3D Navier-Stokes equations in terms of two components of the vorticity

Directory of Open Access Journals (Sweden)

Sadek Gala

2010-10-01

Full Text Available We establish regularity conditions for the 3D Navier-Stokes equation via two components of the vorticity vector. It is known that if a Leray-Hopf weak solution $u$ satisfies $$ ilde{omega}in L^{2/(2-r}(0,T;L^{3/r}(mathbb{R}^3quad hbox{with }0solution on $(0,T]$ (see [5]. We prove the regularity of Leray-Hopf weak solution $u$ under each of the following two (weaker conditions: $$displaylines{ ilde{omega}in L^{2/(2-r}(0,T;dot {mathcal{M}}_{2, 3/r}(mathbb{R}^3quad hbox{for }0regularity criterion improves the results in Chae-Choe [5].

Interaction between copper and radiocesium in Indian mustard and sunflower grown in the hydroponic solution

International Nuclear Information System (INIS)

Shirong Tang; Xiaochang Wang

2002-01-01

Both Indian mustard and sunflower were grown in a hydroponic solution treated with different concentration activities of 134 Cs or with different amounts of copper or with both in order to investigate the interaction between copper and radiocesium. It was found that 134 Cs activity concentration applied in the nutrient solution exerted more influence on the uptake and translocation of copper by Indian mustard than by sunflower. Indian mustard grown in hydroponic solution containing certain levels of copper and being treated with higher 134 Cs activity concentration showed higher uptake of copper than sunflower. However, in the case of root copper concentrations, sunflower showed significantly higher copper immobilization by roots than Indian mustard. It was also found that the presence of copper the the hydroponic solution did modify radiocesium uptake by both species. The application of 1 mg/l in the growth medium could greatly increase the uptake of 134 Cs by both species. With 3 mg/l concentration of copper amended to the solution, the accumulation of 134 Cs by both species was decreased compared to the 1 mg/l copper treatment. These lines of evidence show that there is stronger interaction between copper and radiocesium in Indian mustard than in sunflower during the root uptake through nutrient solution. (author)

3D first-arrival traveltime tomography with modified total variation regularization

Science.gov (United States)

Jiang, Wenbin; Zhang, Jie

2018-02-01

Three-dimensional (3D) seismic surveys have become a major tool in the exploration and exploitation of hydrocarbons. 3D seismic first-arrival traveltime tomography is a robust method for near-surface velocity estimation. A common approach for stabilizing the ill-posed inverse problem is to apply Tikhonov regularization to the inversion. However, the Tikhonov regularization method recovers smooth local structures while blurring the sharp features in the model solution. We present a 3D first-arrival traveltime tomography method with modified total variation (MTV) regularization to preserve sharp velocity contrasts and improve the accuracy of velocity inversion. To solve the minimization problem of the new traveltime tomography method, we decouple the original optimization problem into two following subproblems: a standard traveltime tomography problem with the traditional Tikhonov regularization and a L2 total variation problem. We apply the conjugate gradient method and split-Bregman iterative method to solve these two subproblems, respectively. Our synthetic examples show that the new method produces higher resolution models than the conventional traveltime tomography with Tikhonov regularization. We apply the technique to field data. The stacking section shows significant improvements with static corrections from the MTV traveltime tomography.

Regular expressions cookbook

CERN Document Server

Goyvaerts, Jan

2009-01-01

This cookbook provides more than 100 recipes to help you crunch data and manipulate text with regular expressions. Every programmer can find uses for regular expressions, but their power doesn't come worry-free. Even seasoned users often suffer from poor performance, false positives, false negatives, or perplexing bugs. Regular Expressions Cookbook offers step-by-step instructions for some of the most common tasks involving this tool, with recipes for C#, Java, JavaScript, Perl, PHP, Python, Ruby, and VB.NET. With this book, you will: Understand the basics of regular expressions through a

Regularity criteria for the Navier–Stokes equations based on one component of velocity

Czech Academy of Sciences Publication Activity Database

Guo, Z.; Caggio, M.; Skalák, Zdeněk

2017-01-01

Roč. 35, June (2017), s. 379-396 ISSN 1468-1218 R&D Projects: GA ČR GA14-02067S Grant - others:Západočeská univerzita(CZ) SGS-2016-003; National Natural Science Foundation of China (CN) 11301394 Institutional support: RVO:67985874 Keywords : Navier–Stokes equations * regularity of solutions * regularity criteria * Anisotropic Lebesgue spaces Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.659, year: 2016

Regularity criteria for the Navier–Stokes equations based on one component of velocity

Czech Academy of Sciences Publication Activity Database

Guo, Z.; Caggio, M.; Skalák, Zdeněk

2017-01-01

Roč. 35, June (2017), s. 379-396 ISSN 1468-1218 R&D Projects: GA ČR GA14-02067S Grant - others:Západočeská univerzita(CZ) SGS-2016-003; National Natural Science Foundation of China(CN) 11301394 Institutional support: RVO:67985874 Keywords : Navier–Stokes equations * regularity of solutions * regularity criteria * Anisotropic Lebesgue spaces Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.659, year: 2016

LL-regular grammars

NARCIS (Netherlands)

Nijholt, Antinus

1980-01-01

Culik II and Cogen introduced the class of LR-regular grammars, an extension of the LR(k) grammars. In this paper we consider an analogous extension of the LL(k) grammars called the LL-regular grammars. The relation of this class of grammars to other classes of grammars will be shown. Any LL-regular

Interaction between polymorphisms in aspirin metabolic pathways, regular aspirin use and colorectal cancer risk: A case-control study in unselected white European populations.

Science.gov (United States)

Sheth, Harsh; Northwood, Emma; Ulrich, Cornelia M; Scherer, Dominique; Elliott, Faye; Barrett, Jennifer H; Forman, David; Wolf, C Roland; Smith, Gillian; Jackson, Michael S; Santibanez-Koref, Mauro; Haile, Robert; Casey, Graham; Jenkins, Mark; Win, Aung Ko; Hopper, John L; Marchand, Loic Le; Lindor, Noralane M; Thibodeau, Stephen N; Potter, John D; Burn, John; Bishop, D Timothy

2018-01-01

Regular aspirin use is associated with reduced risk of colorectal cancer (CRC). Variation in aspirin's chemoprevention efficacy has been attributed to the presence of single nucleotide polymorphisms (SNPs). We conducted a meta-analysis using two large population-based case-control datasets, the UK-Leeds Colorectal Cancer Study Group and the NIH-Colon Cancer Family Registry, having a combined total of 3325 cases and 2262 controls. The aim was to assess 42 candidate SNPs in 15 genes whose association with colorectal cancer risk was putatively modified by aspirin use, in the literature. Log odds ratios (ORs) and standard errors were estimated for each dataset separately using logistic regression adjusting for age, sex and study site, and dataset-specific results were combined using random effects meta-analysis. Meta-analysis showed association between SNPs rs6983267, rs11694911 and rs2302615 with CRC risk reduction (All Paspirin use and CRC risk (Pinteraction = 0.01 and 0.02, respectively); stratification by aspirin use showed an association for decreased CRC risk for aspirin users having a wild-type genotype (rs2070959 OR = 0.77, 95% CI = 0.68-0.86; rs1105879 OR = 0.77 95% CI = 0.69-0.86) compared to variant allele cariers. The direction of the interaction however is in contrast to that published in studies on colorectal adenomas. Both SNPs showed potential site-specific interaction with aspirin use and colon cancer risk only (Pinteraction = 0.006 and 0.008, respectively), with the direction of association similar to that observed for CRC. Additionally, they showed interaction between any non-steroidal anti-inflammatory drugs (including aspirin) use and CRC risk (Pinteraction = 0.01 for both). All gene x environment (GxE) interactions however were not significant after multiple test correction. Candidate gene investigation indicated no evidence of GxE interaction between genetic variants in genes involved in aspirin pathways, regular aspirin use and colorectal cancer

An exact solution of two friendly interacting directed walks near a sticky wall

International Nuclear Information System (INIS)

Tabbara, R; Owczarek, A L; Rechnitzer, A

2014-01-01

We find the exact solution of two interacting friendly directed walks (modelling polymers) on the square lattice. These walks are confined to the quarter plane by a horizontal attractive surface, to capture the effects of DNA-denaturation and adsorption. We find the solution to the model’s corresponding generating function by means of the obstinate kernel method. Specifically, we apply this technique in two different instances to establish partial solutions for two simplified generating functions of the same underlying model that ignore either surface or shared contacts. We then subsequently combine our two partial solutions to find the solution for the full generating function in terms of the two simpler variants. This expression guides our analysis of the model, where we find the system exhibits four phases, and proceed to delineate the full phase diagram, showing that all observed phase transitions are second-order. (paper)

Analytical Structuring of Periodic and Regular Cascading Solutions in Self-Pulsing Lasers

Directory of Open Access Journals (Sweden)

Belkacem Meziane

2008-01-01

Full Text Available A newly proposed strong harmonic-expansion method is applied to the laser-Lorenz equations to analytically construct a few typical solutions, including the first few expansions of the well-known period-doubling cascade that characterizes the system in its self-pulsing regime of operation. These solutions are shown to evolve in accordance with the driving frequency of the permanent solution that we recently reported to illustrate the system. The procedure amounts to analytically construct the signal Fourier transform by applying an iterative algorithm that reconstitutes the first few terms of its development.

FPGA-accelerated algorithm for the regular expression matching system

Science.gov (United States)

Russek, P.; Wiatr, K.

2015-01-01

This article describes an algorithm to support a regular expressions matching system. The goal was to achieve an attractive performance system with low energy consumption. The basic idea of the algorithm comes from a concept of the Bloom filter. It starts from the extraction of static sub-strings for strings of regular expressions. The algorithm is devised to gain from its decomposition into parts which are intended to be executed by custom hardware and the central processing unit (CPU). The pipelined custom processor architecture is proposed and a software algorithm explained accordingly. The software part of the algorithm was coded in C and runs on a processor from the ARM family. The hardware architecture was described in VHDL and implemented in field programmable gate array (FPGA). The performance results and required resources of the above experiments are given. An example of target application for the presented solution is computer and network security systems. The idea was tested on nearly 100,000 body-based viruses from the ClamAV virus database. The solution is intended for the emerging technology of clusters of low-energy computing nodes.

Regular periodical public disclosure obligations of public companies

Directory of Open Access Journals (Sweden)

Marjanski Vladimir

2011-01-01

Full Text Available Public companies in the capacity of capital market participants have the obligation to inform the public on their legal and financial status, their general business operations, as well as on the issuance of securities and other financial instruments. Such obligations may be divided into two groups: The first group consists of regular periodical public disclosures, such as the publication of financial reports (annual, semi-annual and quarterly, and the management's reports on the public company's business operations. The second group comprises the obligation of occasional (ad hoc public disclosure. The thesis analyses the obligation of public companies to inform the public in course of their regular reporting. The new Capital Market Law based on two EU Directives (the Transparency Directive and the Directive on Public Disclosure of Inside Information and the Definition of Market Manipulation regulates such obligation of public companies in substantially more detail than the prior Law on the Market of Securities and Other Financial Instruments (hereinafter: ZTHV. Due to the above the ZTHV's provisions are compared to the new solutions within the domain of regular periodical disclosure of the Capital Market Law.

EIT Imaging Regularization Based on Spectral Graph Wavelets.

Science.gov (United States)

Gong, Bo; Schullcke, Benjamin; Krueger-Ziolek, Sabine; Vauhkonen, Marko; Wolf, Gerhard; Mueller-Lisse, Ullrich; Moeller, Knut

2017-09-01

The objective of electrical impedance tomographic reconstruction is to identify the distribution of tissue conductivity from electrical boundary conditions. This is an ill-posed inverse problem usually solved under the finite-element method framework. In previous studies, standard sparse regularization was used for difference electrical impedance tomography to achieve a sparse solution. However, regarding elementwise sparsity, standard sparse regularization interferes with the smoothness of conductivity distribution between neighboring elements and is sensitive to noise. As an effect, the reconstructed images are spiky and depict a lack of smoothness. Such unexpected artifacts are not realistic and may lead to misinterpretation in clinical applications. To eliminate such artifacts, we present a novel sparse regularization method that uses spectral graph wavelet transforms. Single-scale or multiscale graph wavelet transforms are employed to introduce local smoothness on different scales into the reconstructed images. The proposed approach relies on viewing finite-element meshes as undirected graphs and applying wavelet transforms derived from spectral graph theory. Reconstruction results from simulations, a phantom experiment, and patient data suggest that our algorithm is more robust to noise and produces more reliable images.

Existence of weak solutions to first-order stationary mean-field games with Dirichlet conditions

KAUST Repository

Ferreira, Rita

2018-04-19

In this paper, we study first-order stationary monotone mean-field games (MFGs) with Dirichlet boundary conditions. While for Hamilton--Jacobi equations Dirichlet conditions may not be satisfied, here, we establish the existence of solutions of MFGs that satisfy those conditions. To construct these solutions, we introduce a monotone regularized problem. Applying Schaefer\\'s fixed-point theorem and using the monotonicity of the MFG, we verify that there exists a unique weak solution to the regularized problem. Finally, we take the limit of the solutions of the regularized problem and using Minty\\'s method, we show the existence of weak solutions to the original MFG.

Anionic Polyelectrolyte-Cationic Surfactant Interactions in Aqueous Solutions and Foam Films Stability Interactions entre polyélectrolytes anioniques et tensioactifs cationiques en solutions aqueuses et stabilité des films de mousses

Directory of Open Access Journals (Sweden)

Langevin D.

2006-12-01

Full Text Available The objective of this work is to study polymer/surfactant interactions in aqueous solution and at the air/water interface. These interations are involved in many physicochemical phenomena, such as colloidal stabilization and wettability which are of major importance in oil application as for exemple drilling muds. More precisely, we have attempted to characterize interactions between a non surface active anionic copolymer (acrylamide/acrylamide sulfonate and an oppositely charged cationic surfactant (C12 TAB. Our results show a synergestic surface tension lowering (coadsorption at extremely low surfactant concentrations (10 to the power of (-3 to 10 to the power of (-1 CMC. At higher concentrations, namely above the so called Critical Aggregation Concentration (CAC, polymer-surfactant complexes form in the bulk and the macromolecules precipitate out of the solution. Foam films made from these mixed solutions are stable while C12TAB films are unstable. Disjoining pressure measurements on mixed films with surfactant concentration two orders of magnitude below the CAC show the existence of long range repulsive forces and a discrete film thickness transition. At the CAC, we obtain mixed films with gel-like networks that are strongly affected by the film thinning rate. L'objectif de cette étude est d'étudier les interactions polymère/tensioactif en solution aqueuse et à l'interface eau/air. Ces interactions interviennent dans de nombreux phénomènes physico-chimiques tels que la stabilisation de suspensions colloïdales et la mouillabilité qui sont d'une importance majeure dans les applications pétrolières comme, par exemple, les boues de forage. Plus précisément, nous avons essayé de caractériser les interactions entre un copolymère anionique n'ayant pas d'activité de surface (acrylamide/acrylamide sulfoné avec un tensioactif de charge opposée cationique (C12TAB. Nos résultats montrent une diminution synergique de la tension

Existence of global solutions to reaction-diffusion systems via a Lyapunov functional

Directory of Open Access Journals (Sweden)

Said Kouachi

2001-10-01

Full Text Available The purpose of this paper is to construct polynomial functionals (according to solutions of the coupled reaction-diffusion equations which give $L^{p}$-bounds for solutions. When the reaction terms are sufficiently regular, using the well known regularizing effect, we deduce the existence of global solutions. These functionals are obtained independently of work done by Malham and Xin [11].

Bolting multicenter solutions

Energy Technology Data Exchange (ETDEWEB)

Bena, Iosif [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette Cedex (France); Bossard, Guillaume [Centre de Physique Théorique, Ecole Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau Cedex (France); Katmadas, Stefanos; Turton, David [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette Cedex (France)

2017-01-30

We introduce a solvable system of equations that describes non-extremal multicenter solutions to six-dimensional ungauged supergravity coupled to tensor multiplets. The system involves a set of functions on a three-dimensional base metric. We obtain a family of non-extremal axisymmetric solutions that generalize the known multicenter extremal solutions, using a particular base metric that introduces a bolt. We analyze the conditions for regularity, and in doing so we show that this family does not include solutions that contain an extremal black hole and a smooth bolt. We determine the constraints that are necessary to obtain smooth horizonless solutions involving a bolt and an arbitrary number of Gibbons-Hawking centers.

Interaction between blood-brain barrier and glymphatic system in solute clearance.

Science.gov (United States)

Verheggen, I C M; Van Boxtel, M P J; Verhey, F R J; Jansen, J F A; Backes, W H

2018-03-30

Neurovascular pathology concurs with protein accumulation, as the brain vasculature is important for waste clearance. Interstitial solutes, such as amyloid-β, were previously thought to be primarily cleared from the brain by blood-brain barrier transport. Recently, the glymphatic system was discovered, in which cerebrospinal fluid is exchanged with interstitial fluid, facilitated by the aquaporin-4 water channels on the astroglial endfeet. Glymphatic flow can clear solutes from the interstitial space. Blood-brain barrier transport and glymphatic clearance likely serve complementary roles with partially overlapping mechanisms providing a well-conditioned neuronal environment. Disruption of these mechanisms can lead to protein accumulation and may initiate neurodegenerative disorders, for instance amyloid-β accumulation and Alzheimer's disease. Although both mechanisms seem to have a similar purpose, their interaction has not been clearly discussed previously. This review focusses on this interaction in healthy and pathological conditions. Future health initiatives improving waste clearance might delay or even prevent onset of neurodegenerative disorders. Defining glymphatic flow kinetics using imaging may become an alternative way to identify those at risk of Alzheimer's disease. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

The significance of the structural regularity for the seismic response of buildings

International Nuclear Information System (INIS)

Hampe, E.; Goldbach, R.; Schwarz, J.

1991-01-01

The paper gives an state-of-the-art report about the international design practice and submits fundamentals for a systematic approach to the solution of that problem. Different criteria of regularity are presented and discussed with respect to EUROCODE Nr. 8. Still remaining questions and the main topics of future research activities are announced and come into consideration. Frame structures with or without additional stiffening wall elements are investigated to illustrate the qualitative differences of the vibrational properties and the earthquake response of regular and irregular systems. (orig./HP) [de

Total variation regularization in measurement and image space for PET reconstruction

KAUST Repository

Burger, M

2014-09-18

© 2014 IOP Publishing Ltd. The aim of this paper is to test and analyse a novel technique for image reconstruction in positron emission tomography, which is based on (total variation) regularization on both the image space and the projection space. We formulate our variational problem considering both total variation penalty terms on the image and on an idealized sinogram to be reconstructed from a given Poisson distributed noisy sinogram. We prove existence, uniqueness and stability results for the proposed model and provide some analytical insight into the structures favoured by joint regularization. For the numerical solution of the corresponding discretized problem we employ the split Bregman algorithm and extensively test the approach in comparison to standard total variation regularization on the image. The numerical results show that an additional penalty on the sinogram performs better on reconstructing images with thin structures.

Error estimates in projective solutions of the radon equation

International Nuclear Information System (INIS)

Lubuma, M.S.

1991-04-01

The model Radon equation is the integral equation of the second kind defined by the interior limits of the electrostatic double layer potential relative to a curve with one angular point and characterized by the non compactness of the operator with respect to the maximum norm. It is shown that the solution to this equation is decomposable into a regular part and a finite linear combination of intrinsic singular functions. The maximal regularity of the solution and explicit formulae for the coefficients of the singular functions are given. The regularity permits to specify how slow the convergence of the classical projection method is, while the above mentioned formulae lead to modified projection methods of the Dual Singular Function Method type, with better approximations for the solution and for the coefficients of singularities. (author). 23 refs

Singular pontentials and analytic regularization in classical Yang-Mills equations

International Nuclear Information System (INIS)

Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.

1978-11-01

The class of instanton solutions with 'extension' parameter lambda 2 positive is extended to lambda 2 negative. The nature of the singular sphere of radius 'lambda' is analized in the light of the analytical regularization method. This leads to well defined solutions of the Yang-Mills equations. Some of them are sourceless ('+-io' and 'Vp'), others correspond to currents concentrated on the sphere of singularity ('+' and '-'). Although the equations are non-linear, the 'Vp' solution turns out to be real part of the '+-io' solutions. The anzats of t'Hooft for the superposition of instantons is used to sum the contributions corresponding to lambda 2 with positive and negative signs. A subsequent limiting process allows then the construction of solutions of the 'multipole' type. The general situation of potentials having a denominator D, with a corresponding surface of singularity at D=0, is also considered in the same light [pt

DNA Modified with Metal Nanoparticles: Preparation and Characterization of Ordered Metal-DNA Nanostructures in a Solution and on a Substrate

Directory of Open Access Journals (Sweden)

Nina Kasyanenko

2016-01-01

Full Text Available DNA interaction with silver and aluminum nanoparticles in a solution has been investigated with the AFM, SEM, dynamic light scattering, viscometry, and spectral methods. The comparison of DNA interaction with nanoparticles synthesized by the reduction of Ag+ ions and with nanoparticles obtained by the electric discharge plasma method was done. DNA metallization in a solution and on n-silicon surface with metal nanoparticles or by the reduction of silver ions after their binding to DNA was executed and studied. It was shown that DNA strands with regular location of silver or aluminum nanoparticles can be prepared. The conditions for the formation of silver nanoparticles and silver nanoclusters on DNA were analyzed.

Use of regularization method in the determination of ring parameters and orbit correction

International Nuclear Information System (INIS)

Tang, Y.N.; Krinsky, S.

1993-01-01

We discuss applying the regularization method of Tikhonov to the solution of inverse problems arising in accelerator operations. This approach has been successfully used for orbit correction on the NSLS storage rings, and is presently being applied to the determination of betatron functions and phases from the measured response matrix. The inverse problem of differential equation often leads to a set of integral equations of the first kind which are ill-conditioned. The regularization method is used to combat the ill-posedness

A Regularization SAA Scheme for a Stochastic Mathematical Program with Complementarity Constraints

Directory of Open Access Journals (Sweden)

Yu-xin Li

2014-01-01

Full Text Available To reflect uncertain data in practical problems, stochastic versions of the mathematical program with complementarity constraints (MPCC have drawn much attention in the recent literature. Our concern is the detailed analysis of convergence properties of a regularization sample average approximation (SAA method for solving a stochastic mathematical program with complementarity constraints (SMPCC. The analysis of this regularization method is carried out in three steps: First, the almost sure convergence of optimal solutions of the regularized SAA problem to that of the true problem is established by the notion of epiconvergence in variational analysis. Second, under MPCC-MFCQ, which is weaker than MPCC-LICQ, we show that any accumulation point of Karash-Kuhn-Tucker points of the regularized SAA problem is almost surely a kind of stationary point of SMPCC as the sample size tends to infinity. Finally, some numerical results are reported to show the efficiency of the method proposed.

Regularization of absorber or doorway states in heavy-particle collisions

International Nuclear Information System (INIS)

Errea, L.F.; Riera, A.; Sanchez, P.

1994-01-01

We present a unified theoretical basis of the recently proposed regularization method of absorber or doorway states. The theory is applicable to the close-coupling solutions of time-dependent Schroedinger equations corresponding to Hamiltonians containing singular terms and with a partial continuum spectrum. The presentation and illustration are restricted to the treatment of atomic collisions. (author)

Stochastic dynamic modeling of regular and slow earthquakes

Science.gov (United States)

Aso, N.; Ando, R.; Ide, S.

2017-12-01

Both regular and slow earthquakes are slip phenomena on plate boundaries and are simulated by a (quasi-)dynamic modeling [Liu and Rice, 2005]. In these numerical simulations, spatial heterogeneity is usually considered not only for explaining real physical properties but also for evaluating the stability of the calculations or the sensitivity of the results on the condition. However, even though we discretize the model space with small grids, heterogeneity at smaller scales than the grid size is not considered in the models with deterministic governing equations. To evaluate the effect of heterogeneity at the smaller scales we need to consider stochastic interactions between slip and stress in a dynamic modeling. Tidal stress is known to trigger or affect both regular and slow earthquakes [Yabe et al., 2015; Ide et al., 2016], and such an external force with fluctuation can also be considered as a stochastic external force. A healing process of faults may also be stochastic, so we introduce stochastic friction law. In the present study, we propose a stochastic dynamic model to explain both regular and slow earthquakes. We solve mode III problem, which corresponds to the rupture propagation along the strike direction. We use BIEM (boundary integral equation method) scheme to simulate slip evolution, but we add stochastic perturbations in the governing equations, which is usually written in a deterministic manner. As the simplest type of perturbations, we adopt Gaussian deviations in the formulation of the slip-stress kernel, external force, and friction. By increasing the amplitude of perturbations of the slip-stress kernel, we reproduce complicated rupture process of regular earthquakes including unilateral and bilateral ruptures. By perturbing external force, we reproduce slow rupture propagation at a scale of km/day. The slow propagation generated by a combination of fast interaction at S-wave velocity is analogous to the kinetic theory of gasses: thermal

Regular perturbation theory for two-electron atoms

International Nuclear Information System (INIS)

Feranchuk, I.D.; Triguk, V.V.

2011-01-01

Regular perturbation theory (RPT) for the ground and excited states of two-electron atoms or ions is developed. It is shown for the first time that summation of the matrix elements from the electron-electron interaction operator over all intermediate states can be calculated in a closed form by means of the two-particle Coulomb Green's function constructed in the Letter. It is shown that the second order approximation of RPT includes the main part of the correlation energy both for the ground and excited states. This approach can be also useful for description of two-electron atoms in external fields. -- Highlights: → We develop regular perturbation theory for the two-electron atoms or ions. → We calculate the sum of the matrix elements over all intermediate states. → We construct the two-particle Coulomb Green's function.

Smooth and robust solutions for Dirichlet boundary control of fluid-solid conjugate heat transfer problems

KAUST Repository

Yan, Yan

2015-01-01

We study a new optimization scheme that generates smooth and robust solutions for Dirichlet velocity boundary control (DVBC) of conjugate heat transfer (CHT) processes. The solutions to the DVBC of the incompressible Navier-Stokes equations are typically nonsmooth, due to the regularity degradation of the boundary stress in the adjoint Navier-Stokes equations. This nonsmoothness is inherited by the solutions to the DVBC of CHT processes, since the CHT process couples the Navier-Stokes equations of fluid motion with the convection-diffusion equations of fluid-solid thermal interaction. Our objective in the CHT boundary control problem is to select optimally the fluid inflow profile that minimizes an objective function that involves the sum of the mismatch between the temperature distribution in the fluid system and a prescribed temperature profile and the cost of the control.Our strategy to resolve the nonsmoothness of the boundary control solution is based on two features, namely, the objective function with a regularization term on the gradient of the control profile on both the continuous and the discrete levels, and the optimization scheme with either explicit or implicit smoothing effects, such as the smoothed Steepest Descent and the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) methods. Our strategy to achieve the robustness of the solution process is based on combining the smoothed optimization scheme with the numerical continuation technique on the regularization parameters in the objective function. In the section of numerical studies, we present two suites of experiments. In the first one, we demonstrate the feasibility and effectiveness of our numerical schemes in recovering the boundary control profile of the standard case of a Poiseuille flow. In the second one, we illustrate the robustness of our optimization schemes via solving more challenging DVBC problems for both the channel flow and the flow past a square cylinder, which use initial

Regularization and the potential of effective field theory in nucleon-nucleon scattering

International Nuclear Information System (INIS)

Phillips, D.R.

1998-04-01

This paper examines the role that regularization plays in the definition of the potential used in effective field theory (EFT) treatments of the nucleon-nucleon interaction. The author considers N N scattering in S-wave channels at momenta well below the pion mass. In these channels (quasi-)bound states are present at energies well below the scale m π 2 /M expected from naturalness arguments. He asks whether, in the presence of such a shallow bound state, there is a regularization scheme which leads to an EFT potential that is both useful and systematic. In general, if a low-lying bound state is present then cutoff regularization leads to an EFT potential which is useful but not systematic, and dimensional regularization with minimal subtraction leads to one which is systematic but not useful. The recently-proposed technique of dimensional regularization with power-law divergence subtraction allows the definition of an EFT potential which is both useful and systematic

An iterative method for Tikhonov regularization with a general linear regularization operator

NARCIS (Netherlands)

Hochstenbach, M.E.; Reichel, L.

2010-01-01

Tikhonov regularization is one of the most popular approaches to solve discrete ill-posed problems with error-contaminated data. A regularization operator and a suitable value of a regularization parameter have to be chosen. This paper describes an iterative method, based on Golub-Kahan

l1- and l2-Norm Joint Regularization Based Sparse Signal Reconstruction Scheme

Directory of Open Access Journals (Sweden)

Chanzi Liu

2016-01-01

Full Text Available Many problems in signal processing and statistical inference involve finding sparse solution to some underdetermined linear system of equations. This is also the application condition of compressive sensing (CS which can find the sparse solution from the measurements far less than the original signal. In this paper, we propose l1- and l2-norm joint regularization based reconstruction framework to approach the original l0-norm based sparseness-inducing constrained sparse signal reconstruction problem. Firstly, it is shown that, by employing the simple conjugate gradient algorithm, the new formulation provides an effective framework to deduce the solution as the original sparse signal reconstruction problem with l0-norm regularization item. Secondly, the upper reconstruction error limit is presented for the proposed sparse signal reconstruction framework, and it is unveiled that a smaller reconstruction error than l1-norm relaxation approaches can be realized by using the proposed scheme in most cases. Finally, simulation results are presented to validate the proposed sparse signal reconstruction approach.

The use of regularization in inferential measurements

International Nuclear Information System (INIS)

Hines, J. Wesley; Gribok, Andrei V.; Attieh, Ibrahim; Uhrig, Robert E.

1999-01-01

Inferential sensing is the prediction of a plant variable through the use of correlated plant variables. A correct prediction of the variable can be used to monitor sensors for drift or other failures making periodic instrument calibrations unnecessary. This move from periodic to condition based maintenance can reduce costs and increase the reliability of the instrument. Having accurate, reliable measurements is important for signals that may impact safety or profitability. This paper investigates how collinearity adversely affects inferential sensing by making the results inconsistent and unrepeatable; and presents regularization as a potential solution (author) (ml)

Thermal expansion and transformation behavior of cerium and plutonium alloys: an application of the Aptekar-Ponyatovsky regular solution model.

Science.gov (United States)

Lawson, A C; Lashley, J C

2011-09-14

In this paper we apply the Aptekar-Ponyatovsky (AP) regular solution thermodynamic model to the analysis of experimental data for the coefficient of thermal expansion (CTE) and determine the AP model parameters for unalloyed cerium metal, Ce-Th-La alloys, and Pu-Ga alloys. We find that the high temperature CTE of cerium metal follows the predictions of the AP model based on low temperature, high pressure data. For Ce-Th-La alloys we use the AP parameters to track the suppression of the first-order γ-α cerium transition. We show the AP model accounts for the negative CTE observed for Pu-Ga alloys and is equivalent to an earlier invar model. Finally, we apply the AP parameters obtained for Pu-Ga alloys to rationalize the observed δ-α transformation pressures of these alloys. We show that the anomalous values of the Grüneisen and Grüneisen-Anderson parameters are important features of the thermal properties of plutonium. A strong analogy between the properties of plutonium and cerium is confirmed.

Regularizations: different recipes for identical situations

International Nuclear Information System (INIS)

Gambin, E.; Lobo, C.O.; Battistel, O.A.

2004-03-01

We present a discussion where the choice of the regularization procedure and the routing for the internal lines momenta are put at the same level of arbitrariness in the analysis of Ward identities involving simple and well-known problems in QFT. They are the complex self-interacting scalar field and two simple models where the SVV and AVV process are pertinent. We show that, in all these problems, the conditions to symmetry relations preservation are put in terms of the same combination of divergent Feynman integrals, which are evaluated in the context of a very general calculational strategy, concerning the manipulations and calculations involving divergences. Within the adopted strategy, all the arbitrariness intrinsic to the problem are still maintained in the final results and, consequently, a perfect map can be obtained with the corresponding results of the traditional regularization techniques. We show that, when we require an universal interpretation for the arbitrariness involved, in order to get consistency with all stated physical constraints, a strong condition is imposed for regularizations which automatically eliminates the ambiguities associated to the routing of the internal lines momenta of loops. The conclusion is clean and sound: the association between ambiguities and unavoidable symmetry violations in Ward identities cannot be maintained if an unique recipe is required for identical situations in the evaluation of divergent physical amplitudes. (author)

Regular Expression Pocket Reference

CERN Document Server

Stubblebine, Tony

2007-01-01

This handy little book offers programmers a complete overview of the syntax and semantics of regular expressions that are at the heart of every text-processing application. Ideal as a quick reference, Regular Expression Pocket Reference covers the regular expression APIs for Perl 5.8, Ruby (including some upcoming 1.9 features), Java, PHP, .NET and C#, Python, vi, JavaScript, and the PCRE regular expression libraries. This concise and easy-to-use reference puts a very powerful tool for manipulating text and data right at your fingertips. Composed of a mixture of symbols and text, regular exp

Geochemical and numerical modelling of interactions between solid solutions and an aqueous solution. Extension of a reactive transport computer code called Archimede and application to reservoirs diagenesis; Modelisation geochimique et numerique des interactions entre des solutions solides et une solution aqueuse: extension du logiciel de reaction-transport archimede et application a la diagenese des reservoirs

Energy Technology Data Exchange (ETDEWEB)

Nourtier-Mazauric, E.

2003-03-15

This thesis presents a thermodynamic and kinetic model of interactions between a fluid and ideal solid solutions represented by several end-members. The reaction between a solid solution and the aqueous solution results from the competition between the stoichiometric dissolution of the initial solid solution and the co-precipitation of the least soluble solid solution in the fluid at considered time. This model was implemented in ARCHIMEDE, a computer code of reactive transport in porous media, then applied to various examples. In the case of binary solid solutions, a graphical method allowed to determine the compositions of the precipitating solid solutions, with the aid of the end-member chemical potentials. The obtained program could be used to notably model the diagenesis of clayey or carbonated oil reservoirs, or the ground pollutant dispersion. (author)

Direct interaction between linear electron transfer chains and solute transport systems in bacteria

NARCIS (Netherlands)

Elferink, Marieke G.L.; Hellingwerf, Klaas J.; Belkum, Marco J. van; Poolman, Bert; Konings, Wil N.

1984-01-01

In studies on alanine and lactose transport in Rhodopseudomonas sphaeroides we have demonstrated that the rate of solute uptake in this phototrophic bacterium is regulated by the rate of light-induced cyclic electron transfer. In the present paper the interaction between linear electron transfer

Singular potentials and analytic regularization in classical Yang-Mills equations

International Nuclear Information System (INIS)

Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.

1978-10-01

The class of instanton solutions with 'extension' parameter Λ 2 positive is extended to Λ 2 negative. The nature of the singular sphere of radius |Λ| is analized in the light of the analytical regularization method. This leads to well defined solutions of the Yang - Mills equations. Some of them are sourceless ('+- i o' and 'Vp'), others correspond to currents concentrated on the sphere of singularity ('+' and '-'). Although the equations are non-linear, the 'Vp' solutions turns out to be the real part of the '+- i o' solutions. The anzats of t'Hooft for the superposition of instantons is used to sum the contributions corresponding to Λ 2 with positive and negative signs. A subsequent limiting process allows then the construction of solutions of the 'multipole' type. The general situation of potentials having a denominator D, with a corresponding surface of singularity at D=0, is also considered in the same light. (Author) [pt

New class of inhomogeneous cosmological perfect-fluid solutions without big-bang singularity

Energy Technology Data Exchange (ETDEWEB)

Senovilla, J.M.M. (Grupo de Fisica Teorica, Departamento de Fisica, Ingenieria y Radiologia Medica, Facultad de Ciencias, Universidad de Salamanca, 37008 Salmanaca (Spain))

1990-05-07

A new class of exact solutions to Einstein's field equations with a perfect-fluid source is presented. The solutions describe spatially inhomogeneous cosmological models and have a realistic equation of state {ital p}={rho}/3. The properties of the solutions are discussed. The most remarkable feature is the absence of an initial singularity, the curvature and matter invariants being regular and smooth everywhere. We also present an alternative interpretation of the solution as a globally regular cylindrically symmetric space-time.

Interaction of indium trichloride with calcium carbonate in aqueous solutions

International Nuclear Information System (INIS)

Kochetkova, N.V.; Toptygina, G.M.; Soklakova, O.V.; Evdokimov, V.I.

1991-01-01

Interaction of indium trichloride with calcium carbonate in aqueous solutions was studied, using methods of potentiometry, isothermal solubility and physicochemical computer simulating. The Gibb's energy value for crystal indium trihydroxide formation was calculated on the basis of experimental data on In(OH) 3 solubility. The value obtained was used for estimating equilibrium composition of InCl 3 -HCl-CaCO 3 -CO 2 -H 2 O system at a temperature of 25 deg C and carbon dioxide partial pressure of 0.05 to 1 at

Effect of ternary solute interaction on interfacial segregation and grain boundary embrittlement

Czech Academy of Sciences Publication Activity Database

Lejček, Pavel

2013-01-01

Roč. 48, č. 14 (2013), 4965-4972 ISSN 0022-2461 R&D Projects: GA MŠk(CZ) LM2011026; GA ČR GAP108/12/0144 Institutional research plan: CEZ:AV0Z10100520 Keywords : interfacial segregation * intergranular embrittlement * solute interaction * modeling * thermodynamics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.305, year: 2013

Regularized semiclassical limits: Linear flows with infinite Lyapunov exponents

KAUST Repository

Athanassoulis, Agissilaos; Katsaounis, Theodoros; Kyza, Irene

2016-01-01

Semiclassical asymptotics for Schrödinger equations with non-smooth potentials give rise to ill-posed formal semiclassical limits. These problems have attracted a lot of attention in the last few years, as a proxy for the treatment of eigenvalue crossings, i.e. general systems. It has recently been shown that the semiclassical limit for conical singularities is in fact well-posed, as long as the Wigner measure (WM) stays away from singular saddle points. In this work we develop a family of refined semiclassical estimates, and use them to derive regularized transport equations for saddle points with infinite Lyapunov exponents, extending the aforementioned recent results. In the process we answer a related question posed by P.L. Lions and T. Paul in 1993. If we consider more singular potentials, our rigorous estimates break down. To investigate whether conical saddle points, such as -|x|, admit a regularized transport asymptotic approximation, we employ a numerical solver based on posteriori error control. Thus rigorous upper bounds for the asymptotic error in concrete problems are generated. In particular, specific phenomena which render invalid any regularized transport for -|x| are identified and quantified. In that sense our rigorous results are sharp. Finally, we use our findings to formulate a precise conjecture for the condition under which conical saddle points admit a regularized transport solution for the WM. © 2016 International Press.

Regularized semiclassical limits: Linear flows with infinite Lyapunov exponents

KAUST Repository

Athanassoulis, Agissilaos

2016-08-30

Semiclassical asymptotics for Schrödinger equations with non-smooth potentials give rise to ill-posed formal semiclassical limits. These problems have attracted a lot of attention in the last few years, as a proxy for the treatment of eigenvalue crossings, i.e. general systems. It has recently been shown that the semiclassical limit for conical singularities is in fact well-posed, as long as the Wigner measure (WM) stays away from singular saddle points. In this work we develop a family of refined semiclassical estimates, and use them to derive regularized transport equations for saddle points with infinite Lyapunov exponents, extending the aforementioned recent results. In the process we answer a related question posed by P.L. Lions and T. Paul in 1993. If we consider more singular potentials, our rigorous estimates break down. To investigate whether conical saddle points, such as -|x|, admit a regularized transport asymptotic approximation, we employ a numerical solver based on posteriori error control. Thus rigorous upper bounds for the asymptotic error in concrete problems are generated. In particular, specific phenomena which render invalid any regularized transport for -|x| are identified and quantified. In that sense our rigorous results are sharp. Finally, we use our findings to formulate a precise conjecture for the condition under which conical saddle points admit a regularized transport solution for the WM. © 2016 International Press.

Bootstrap regularity for integro-differential operators and its application to nonlocal minimal surfaces

OpenAIRE

Barrera, Begoña Barrios; Figalli, Alessio; Valdinoci, Enrico

2012-01-01

We prove that $C^{1,\\alpha}$ $s$-minimal surfaces are automatically $C^\\infty$. For this, we develop a new bootstrap regularity theory for solutions of integro-differential equations of very general type, which we believe is of independent interest.

A variational regularization of Abel transform for GPS radio occultation

Directory of Open Access Journals (Sweden)

T.-K. Wee

2018-04-01

Full Text Available In the Global Positioning System (GPS radio occultation (RO technique, the inverse Abel transform of measured bending angle (Abel inversion, hereafter AI is the standard means of deriving the refractivity. While concise and straightforward to apply, the AI accumulates and propagates the measurement error downward. The measurement error propagation is detrimental to the refractivity in lower altitudes. In particular, it builds up negative refractivity bias in the tropical lower troposphere. An alternative to AI is the numerical inversion of the forward Abel transform, which does not incur the integration of error-possessing measurement and thus precludes the error propagation. The variational regularization (VR proposed in this study approximates the inversion of the forward Abel transform by an optimization problem in which the regularized solution describes the measurement as closely as possible within the measurement's considered accuracy. The optimization problem is then solved iteratively by means of the adjoint technique. VR is formulated with error covariance matrices, which permit a rigorous incorporation of prior information on measurement error characteristics and the solution's desired behavior into the regularization. VR holds the control variable in the measurement space to take advantage of the posterior height determination and to negate the measurement error due to the mismodeling of the refractional radius. The advantages of having the solution and the measurement in the same space are elaborated using a purposely corrupted synthetic sounding with a known true solution. The competency of VR relative to AI is validated with a large number of actual RO soundings. The comparison to nearby radiosonde observations shows that VR attains considerably smaller random and systematic errors compared to AI. A noteworthy finding is that in the heights and areas that the measurement bias is supposedly small, VR follows AI very closely in the

A variational regularization of Abel transform for GPS radio occultation

Science.gov (United States)

Wee, Tae-Kwon

2018-04-01

In the Global Positioning System (GPS) radio occultation (RO) technique, the inverse Abel transform of measured bending angle (Abel inversion, hereafter AI) is the standard means of deriving the refractivity. While concise and straightforward to apply, the AI accumulates and propagates the measurement error downward. The measurement error propagation is detrimental to the refractivity in lower altitudes. In particular, it builds up negative refractivity bias in the tropical lower troposphere. An alternative to AI is the numerical inversion of the forward Abel transform, which does not incur the integration of error-possessing measurement and thus precludes the error propagation. The variational regularization (VR) proposed in this study approximates the inversion of the forward Abel transform by an optimization problem in which the regularized solution describes the measurement as closely as possible within the measurement's considered accuracy. The optimization problem is then solved iteratively by means of the adjoint technique. VR is formulated with error covariance matrices, which permit a rigorous incorporation of prior information on measurement error characteristics and the solution's desired behavior into the regularization. VR holds the control variable in the measurement space to take advantage of the posterior height determination and to negate the measurement error due to the mismodeling of the refractional radius. The advantages of having the solution and the measurement in the same space are elaborated using a purposely corrupted synthetic sounding with a known true solution. The competency of VR relative to AI is validated with a large number of actual RO soundings. The comparison to nearby radiosonde observations shows that VR attains considerably smaller random and systematic errors compared to AI. A noteworthy finding is that in the heights and areas that the measurement bias is supposedly small, VR follows AI very closely in the mean refractivity

Interaction of Celestine Concentrate and Reagent Grade SrSO4 with Oxalate Solutions

Directory of Open Access Journals (Sweden)

Abdullah Obut

2012-12-01

Full Text Available The interaction of reagent grade strontium sulphate and celestine concentrate with aqueous solutions of oxalic acid, sodiumoxalate and ammonium oxalate for the production of strontium carbonate were investigated for different oxalate compound:SrSO4 moleratios and reaction times using x-ray diffraction analysis and dissolution tests. Under the same experimental conditions, it was foundthat aqueous oxalic acid and sodium oxalate solutions had no or little effect on reagent grade strontium sulphate or celestineconcentrate, but aqueous ammonium oxalate solution converted them into strontium oxalate hydrate. Strontium carbonate was obtainedat conversion ratios of 74.7% for the celestine concentrate and 84.6 % for the reagent grade strontium sulphate by the decompositionof the obtained strontium oxalate hydrate at 600 °C under air atmosphere.

Iterative regularization in intensity-modulated radiation therapy optimization

International Nuclear Information System (INIS)

Carlsson, Fredrik; Forsgren, Anders

2006-01-01

A common way to solve intensity-modulated radiation therapy (IMRT) optimization problems is to use a beamlet-based approach. The approach is usually employed in a three-step manner: first a beamlet-weight optimization problem is solved, then the fluence profiles are converted into step-and-shoot segments, and finally postoptimization of the segment weights is performed. A drawback of beamlet-based approaches is that beamlet-weight optimization problems are ill-conditioned and have to be regularized in order to produce smooth fluence profiles that are suitable for conversion. The purpose of this paper is twofold: first, to explain the suitability of solving beamlet-based IMRT problems by a BFGS quasi-Newton sequential quadratic programming method with diagonal initial Hessian estimate, and second, to empirically show that beamlet-weight optimization problems should be solved in relatively few iterations when using this optimization method. The explanation of the suitability is based on viewing the optimization method as an iterative regularization method. In iterative regularization, the optimization problem is solved approximately by iterating long enough to obtain a solution close to the optimal one, but terminating before too much noise occurs. Iterative regularization requires an optimization method that initially proceeds in smooth directions and makes rapid initial progress. Solving ten beamlet-based IMRT problems with dose-volume objectives and bounds on the beamlet-weights, we find that the considered optimization method fulfills the requirements for performing iterative regularization. After segment-weight optimization, the treatments obtained using 35 beamlet-weight iterations outperform the treatments obtained using 100 beamlet-weight iterations, both in terms of objective value and of target uniformity. We conclude that iterating too long may in fact deteriorate the quality of the deliverable plan

Interaction of radiation-generated radicals with myoglobin in aqueous solution

International Nuclear Information System (INIS)

Whitburn, K.D.; Hoffman, M.Z.

1984-01-01

The interaction of radiation-generated OH/H with oxymyoglobin (MbO 2 ) has been studied in the presence of catalase at pH 7.3 over the range of 5 to 510 μM O 2 . The conversion of MbO 2 to heme-modified products has been examined under conditions where depletion of O 2 in irradiated solutions both can and cannot be compensated by O 2 -transfer across the solution phase boundary. In the theoretical limit of [O 2 ] -> 0 in bulk solution, MbO 2 is converted stoichiometrically to ferri- and ferromyoglobin with G(-MbO 2 ) approx.= 6.0, G(ferroMb) approx.3.0, and G(ferriMb) approx.= 3.0. An increase in [O 2 ] in bulk solution beyond the zero-limit progressively suppresses the conversion of MbO 2 to the heme-modified derivatives. At [O 2 ] >300 μM, an O 2 -independent path of ferriMb formation with G approx.= 0.6 is evident. Two sources of ferriMb induced by OH/H are proposed: an O 2 -independent path involving direct oxidative attack of OH at the oxyferroheme, and O 2 -dependent paths of production of ferriMb and ferroMb involving the mediation of O 2 -scavengeable secondary hemeprotein radicals. It is suggested that the modifications of the heme group in the absence of O 2 are accompanied by redox modifications on the globin moiety. (author)

Application of Differential Colorimetry To Evaluate Anthocyanin-Flavonol-Flavanol Ternary Copigmentation Interactions in Model Solutions.

Science.gov (United States)

Gordillo, Belén; Rodríguez-Pulido, Francisco J; González-Miret, M Lourdes; Quijada-Morín, Natalia; Rivas-Gonzalo, Julián C; García-Estévez, Ignacio; Heredia, Francisco J; Escribano-Bailón, M Teresa

2015-09-09

The combined effect of anthocyanin-flavanol-flavonol ternary interactions on the colorimetric and chemical stability of malvidin-3-glucoside has been studied. Model solutions with fixed malvidin-3-glucoside/(+)-catechin ratio (MC) and variable quercetin-3-β-d-glucoside concentration (MC+Q) and solutions with fixed malvidin-3-glucoside/quercetin-3-β-d-glucoside ratio (MQ) and variable (+)-catechin concentration (MQ+C) were tested at levels closer to those existing in wines. Color variations during storage were evaluated by differential colorimetry. Changes in the anthocyanin concentration were monitored by HPLC-DAD. CIELAB color-difference formulas were demonstrated to be of practical interest to assess the stronger and more stable interaction of quercetin-3-β-d-glucoside with MC binary mixture than (+)-catechin with MQ mixture. The results imply that MC+Q ternary solutions kept their intensity and bluish tonalities for a longer time in comparison to MQ+C solutions. The stability of malvidin-3-glucoside improves when the concentration of quercetin-3-β-d-glucoside increases in MC+Q mixtures, whereas the addition of (+)-catechin in MQ+C mixtures resulted in an opposite effect.

Numerical simulation of the regularized long wave equation by He's homotopy perturbation method

Energy Technology Data Exchange (ETDEWEB)

Inc, Mustafa [Department of Mathematics, Firat University, 23119 Elazig (Turkey)], E-mail: minc@firat.edu.tr; Ugurlu, Yavuz [Department of Mathematics, Firat University, 23119 Elazig (Turkey)

2007-09-17

In this Letter, we present the homotopy perturbation method (shortly HPM) for obtaining the numerical solution of the RLW equation. We obtain the exact and numerical solutions of the Regularized Long Wave (RLW) equation for certain initial condition. The initial approximation can be freely chosen with possible unknown constants which can be determined by imposing the boundary and initial conditions. Comparison of the results with those of other methods have led us to significant consequences. The numerical solutions are compared with the known analytical solutions.

Friction of N-bead macromolecules in solution: Effects of the bead-solvent interaction

International Nuclear Information System (INIS)

Uvarov, Alexander; Fritzsche, Stephan

2006-01-01

The role of the bead-solvent interaction has been studied for its influence on the dynamics of an N-bead macromolecule which is immersed into a solution. Using a Fokker-Planck equation for the phase-space distribution function of the macromolecule, we show that all the effects of the solution can be treated entirely in terms of the friction tensors which are assigned to each pair of interacting beads in the chain. For the high-density as well as for the critical solvent, the properties of these tensors are discussed in detail and are calculated by using several (realistic) choices of the bead-solvent potential. From the friction tensors, moreover, an expression for the center-of-mass friction coefficient of a (N-bead) chain macromolecule is derived. Numerical data for this coefficient for 'truncated' Lennard-Jones bead-solvent potential are compared with results from molecular dynamic simulations and from the phenomenological theoretical data as found in the literature

Vector boson star solutions with a quartic order self-interaction

Science.gov (United States)

Minamitsuji, Masato

2018-05-01

We investigate boson star (BS) solutions in the Einstein-Proca theory with the quartic order self-interaction of the vector field λ (AμA¯ μ)2/4 and the mass term μ A¯ μAμ/2 , where Aμ is the complex vector field and A¯μ is the complex conjugate of Aμ, and λ and μ are the coupling constant and the mass of the vector field, respectively. The vector BSs are characterized by the two conserved quantities, the Arnowitt-Deser-Misner (ADM) mass and the Noether charge associated with the global U (1 ) symmetry. We show that in comparison with the case without the self-interaction λ =0 , the maximal ADM mass and Noether charge increase for λ >0 and decrease for λ vector field above which there is no vector BS solution, and for λ >0 it can be expressed by the simple analytic expression. For a sufficiently large positive coupling Λ ≔Mpl2λ /(8 π μ2)≫1 , the maximal ADM mass and Noether charge of the vector BSs are obtained from the critical central amplitude and of O [√{λ }Mpl3/μ2ln (λ Mpl2/μ2)] , which is different from that of the scalar BSs, O (√{λϕ }Mpl3/μϕ2) , where λϕ and μϕ are the coupling constant and the mass of the complex scalar field.

A New Method for Optimal Regularization Parameter Determination in the Inverse Problem of Load Identification

Directory of Open Access Journals (Sweden)

Wei Gao

2016-01-01

Full Text Available According to the regularization method in the inverse problem of load identification, a new method for determining the optimal regularization parameter is proposed. Firstly, quotient function (QF is defined by utilizing the regularization parameter as a variable based on the least squares solution of the minimization problem. Secondly, the quotient function method (QFM is proposed to select the optimal regularization parameter based on the quadratic programming theory. For employing the QFM, the characteristics of the values of QF with respect to the different regularization parameters are taken into consideration. Finally, numerical and experimental examples are utilized to validate the performance of the QFM. Furthermore, the Generalized Cross-Validation (GCV method and the L-curve method are taken as the comparison methods. The results indicate that the proposed QFM is adaptive to different measuring points, noise levels, and types of dynamic load.

On convergence and convergence rates for Ivanov and Morozov regularization and application to some parameter identification problems in elliptic PDEs

Science.gov (United States)

Kaltenbacher, Barbara; Klassen, Andrej

2018-05-01

In this paper we provide a convergence analysis of some variational methods alternative to the classical Tikhonov regularization, namely Ivanov regularization (also called the method of quasi solutions) with some versions of the discrepancy principle for choosing the regularization parameter, and Morozov regularization (also called the method of the residuals). After motivating nonequivalence with Tikhonov regularization by means of an example, we prove well-definedness of the Ivanov and the Morozov method, convergence in the sense of regularization, as well as convergence rates under variational source conditions. Finally, we apply these results to some linear and nonlinear parameter identification problems in elliptic boundary value problems.

Regularization and renormalization of quantum field theory in curved space-time

International Nuclear Information System (INIS)

Bernard, C.; Duncan, A.

1977-01-01

It is proposed that field theories quantized in a curved space-time manifold can be conveniently regularized and renormalized with the aid of Pauli-Villars regulator fields. The method avoids the conceptual difficulties of covariant point-separation approaches, by starting always from a manifestly generally covariant action, and the technical limitations of the dimensional reqularization approach, which requires solution of the theory in arbitrary dimension in order to go beyond a weak-field expansion. An action is constructed which renormalizes the weak-field perturbation theory of a massive scalar field in two space-time dimensions--it is shown that the trace anomaly previously found in dimensional regularization and some point-separation calculations also arises in perturbation theory when the theory is Pauli-Villars regulated. One then studies a specific solvable two-dimensional model of a massive scalar field in a Robertson-Walker asymptotically flat universe. It is shown that the action previously considered leads, in this model, to a well defined finite expectation value for the stress-energy tensor. The particle production (less than 0 in/vertical bar/theta/sup mu nu/(x,t)/vertical bar/0 in greater than for t → + infinity) is computed explicitly. Finally, the validity of weak-field perturbation theory (in the appropriate range of parameters) is checked directly in the solvable model, and the trace anomaly computed in the asymptotic regions t→ +- infinity independently of any weak field approximation. The extension of the model to higher dimensions and the renormalization of interacting (scalar) field theories are briefly discussed

Exact solution of an Ising model with competing interactions on a Cayley tree

CERN Document Server

Ganikhodjaev, N N; Wahiddin, M R B

2003-01-01

The exact solution of an Ising model with competing restricted interactions on the Cayley tree, and in the absence of an external field is presented. A critical curve is defined where it is possible to get phase transitions above it, and a single Gibbs state is obtained elsewhere.

A calorimetric study of the interactions in the aqueous solutions of lysozyme in the presence of denaturing cosolvents

Energy Technology Data Exchange (ETDEWEB)

Castronuovo, Giuseppina, E-mail: giuseppina.castronuovo@unina.it [Department of Chemistry, University Federico II of Naples, Complesso Universitario Monte S. Angelo, via Cintia, 80126 Naples (Italy); Niccoli, Marcella [Department of Chemistry, University Federico II of Naples, Complesso Universitario Monte S. Angelo, via Cintia, 80126 Naples (Italy)

2012-09-10

Highlights: Black-Right-Pointing-Pointer A thermodynamic method is reported to monitor the chemical denaturation of lysozyme. Black-Right-Pointing-Pointer The enthalpic interaction coefficients are very useful parameters to gain information about the mechanism through which two hydrated molecules interact in solution. Black-Right-Pointing-Pointer Hypotheses are proposed about the mechanism underlying the denaturation of lysozyme induced by high concentrations of urea or ethanol. - Abstract: A thermodynamic method is reported to monitor the chemical denaturation of lysozyme. Heats of dilution of the protein in concentrated aqueous solutions of urea or ethanol have been determined at 298.15 K by flow microcalorimetry. The pairwise enthalpic interaction coefficients of the protein in the different solvent media are derived. These parameters allow to gain information about the influence of the cosolvents on the interactions acting between two interacting hydrated molecules of lysozyme, hence on the denaturation process. At increasing urea concentration, up to about 6 mol kg{sup -1}, the values of the interaction coefficients are large and negative and remain almost unaltered. The invariance of the coefficients underlines that, even in highly concentrated urea, the hydration shell of the protein is such to maintain essentially unaltered the native conformation. At higher urea concentrations, a sudden change in the sign of the coefficients monitors the variation in the interactions between two hydrated denatured protein molecules. The same trend is found when ethanol is the cosolvent. At increasing concentration of the cosolvent, coefficients are, at first, almost invariant. After that, denaturation occurs, detected as a jump toward much more negative values. The results obtained are rationalized on the basis of those previously found for small model molecules in concentrated solutions of urea or ethanol. The thermodynamic framework allows useful comments to be made on

A calorimetric study of the interactions in the aqueous solutions of lysozyme in the presence of denaturing cosolvents

International Nuclear Information System (INIS)

Castronuovo, Giuseppina; Niccoli, Marcella

2012-01-01

Highlights: ► A thermodynamic method is reported to monitor the chemical denaturation of lysozyme. ► The enthalpic interaction coefficients are very useful parameters to gain information about the mechanism through which two hydrated molecules interact in solution. ► Hypotheses are proposed about the mechanism underlying the denaturation of lysozyme induced by high concentrations of urea or ethanol. - Abstract: A thermodynamic method is reported to monitor the chemical denaturation of lysozyme. Heats of dilution of the protein in concentrated aqueous solutions of urea or ethanol have been determined at 298.15 K by flow microcalorimetry. The pairwise enthalpic interaction coefficients of the protein in the different solvent media are derived. These parameters allow to gain information about the influence of the cosolvents on the interactions acting between two interacting hydrated molecules of lysozyme, hence on the denaturation process. At increasing urea concentration, up to about 6 mol kg −1 , the values of the interaction coefficients are large and negative and remain almost unaltered. The invariance of the coefficients underlines that, even in highly concentrated urea, the hydration shell of the protein is such to maintain essentially unaltered the native conformation. At higher urea concentrations, a sudden change in the sign of the coefficients monitors the variation in the interactions between two hydrated denatured protein molecules. The same trend is found when ethanol is the cosolvent. At increasing concentration of the cosolvent, coefficients are, at first, almost invariant. After that, denaturation occurs, detected as a jump toward much more negative values. The results obtained are rationalized on the basis of those previously found for small model molecules in concentrated solutions of urea or ethanol. The thermodynamic framework allows useful comments to be made on the possible mode of action of the two cosolvents on the stability of proteins

On solubility of perchloric (periodic) acid and α-cyanacetanmide in aqueous solutions at 25 deg C

International Nuclear Information System (INIS)

Omarova, R.A.; Balysbekov, S.M.; Erkasov, R.Sh.; Nikolenko, O.N.

1996-01-01

Acid-base interaction within perchloric (periodic) acid-α-cyanacetamide-water systems in studied by method of solubility under isothermal conditions at 25 deg C. Solubility regularities of crystalline α-cyanacetamide in perchloric and periodic acid solutions are determined, the concentration limits of formation of a new solid phase-tris(α-cyanacetamide) perchlorate within perchloric acid-α-cyanacetamide-water system are determined. The compound is identified by means of chemical and X-ray phase analyses, its density and melting temperature are determined. Iodic acid and α-cyanacetamide water solution base system is shown to belong to a simple eutonic type. 2 refs., 3 figs., 2 tabs

Theoretical investigation of interaction of sorbitol molecules with alcohol dehydrogenase in aqueous solution using molecular dynamics simulation.

Science.gov (United States)

Bahrami, Homayoon; Zahedi, Mansour; Moosavi-Movahedi, Ali Akbar; Azizian, Homa; Amanlou, Massoud

2011-03-01

The nature of protein-sorbitol-water interaction in solution at the molecular level, has been investigated using molecular dynamics simulations. In order to do this task, two molecular dynamics simulations of the protein ADH in solution at room temperature have been carried out, one in the presence (about 0.9 M) and another in the absence of sorbitol. The results show that the sorbitol molecules cluster and move toward the protein, and form hydrogen bonds with protein. Also, coating by sorbitol reduces the conformational fluctuations of the protein compared to the sorbitol-free system. Thus, it is concluded that at moderate concentration of sorbitol solution, sorbitol molecules interact with ADH via many H-bonds that prevent the protein folding. In fact, at more concentrated sorbitol solution, water and sorbitol molecules accumulate around the protein surface and form a continuous space-filling network to reduce the protein flexibility. Namely, in such solution, sorbitol molecules can stabilize a misfolded state of ADH, and prevent the protein from folding to its native structure.

Understanding of increased diffuse scattering in regular arrays of fluctuating resonant particles

DEFF Research Database (Denmark)

Andryieuski, Andrei; Petrov, Mihail; Lavrinenko, Andrei

2015-01-01

In this presentation we will discuss the analytical and numerical approaches to modeling electromagnetic properties of geometrically regular subwavelength 2D arrays of random resonant plasmonic particles. Amorphous metamaterials and metasurfaces attract interest of the scientific community due...... with regular periodic arrangements of resonant nanoparticles of random polarizability/size/material at normal plane-wave incidence. We show that randomness of the polarizability is related to increase in diffused scattering and we relate this phenomenon to a modification of the dipoles’ interaction constant...

Solute-solvent interactions in chloroform solutions of halogenated symmetric double Schiff bases of 1,1'-bis(4-aminophenyl)cyclohexane at 308.15 K according to ultrasonic and viscosity data

Science.gov (United States)

Gangani, B. J.; Patel, J. P.; Parsania, P. H.

2015-12-01

The density, viscosity and ultrasonic speed (2 MHz) of chloroform solutions of halogenated symmetric double Schiff bases of 1,1'-bis(4-aminophenyl)cyclohexane were investigated at 308.15 K. Various acoustical parameters such as specific acoustical impedance ( Z), adiabatic compressibility ( Ka), Rao's molar sound function ( R m), van der Waals constant ( b), internal pressure (π), free volume ( V f), intermolecular free path length ( L f), classical absorption coefficient (α/ f 2)Cl) and viscous relaxation time (τ) were determine using ultrasonic speed ( U), viscosity (η) and density (ρ) data of Schiff bases solutions and correlated with concentration. Linear increase of Z, b, R, τ, and (α/ f 2)Cl except π (nonlinear) and linear decrease of Ka and L f except V f (nonlinear) with increasing concentration of Schiff bases suggested presence of strong molecular interactions in the solutions. The positive values of solvation number further supported strong molecular interactions in the solutions. The nature and position of halogen substituent also affected the strength of molecular interactions.

Extensive regularization of the coupled cluster methods based on the generating functional formalism: Application to gas-phase benchmarks and to the SN2 reaction of CHCl3 and OH- in water

International Nuclear Information System (INIS)

Kowalski, Karol; Valiev, Marat

2009-01-01

The recently introduced energy expansion based on the use of generating functional (GF) [K. Kowalski and P. D. Fan, J. Chem. Phys. 130, 084112 (2009)] provides a way of constructing size-consistent noniterative coupled cluster (CC) corrections in terms of moments of the CC equations. To take advantage of this expansion in a strongly interacting regime, the regularization of the cluster amplitudes is required in order to counteract the effect of excessive growth of the norm of the CC wave function. Although proven to be efficient, the previously discussed form of the regularization does not lead to rigorously size-consistent corrections. In this paper we address the issue of size-consistent regularization of the GF expansion by redefining the equations for the cluster amplitudes. The performance and basic features of proposed methodology are illustrated on several gas-phase benchmark systems. Moreover, the regularized GF approaches are combined with quantum mechanical molecular mechanics module and applied to describe the S N 2 reaction of CHCl 3 and OH - in aqueous solution.

Regularity theory for mean-field game systems

CERN Document Server

Gomes, Diogo A; Voskanyan, Vardan

2016-01-01

Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

Regularity Theory for Mean-Field Game Systems

KAUST Repository

Gomes, Diogo A.

2016-09-14

Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

Regularity Theory for Mean-Field Game Systems

KAUST Repository

Gomes, Diogo A.; Pimentel, Edgard A.; Voskanyan, Vardan K.

2016-01-01

Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

Inverse problems with Poisson data: statistical regularization theory, applications and algorithms

International Nuclear Information System (INIS)

Hohage, Thorsten; Werner, Frank

2016-01-01

Inverse problems with Poisson data arise in many photonic imaging modalities in medicine, engineering and astronomy. The design of regularization methods and estimators for such problems has been studied intensively over the last two decades. In this review we give an overview of statistical regularization theory for such problems, the most important applications, and the most widely used algorithms. The focus is on variational regularization methods in the form of penalized maximum likelihood estimators, which can be analyzed in a general setup. Complementing a number of recent convergence rate results we will establish consistency results. Moreover, we discuss estimators based on a wavelet-vaguelette decomposition of the (necessarily linear) forward operator. As most prominent applications we briefly introduce Positron emission tomography, inverse problems in fluorescence microscopy, and phase retrieval problems. The computation of a penalized maximum likelihood estimator involves the solution of a (typically convex) minimization problem. We also review several efficient algorithms which have been proposed for such problems over the last five years. (topical review)

The geometry of continuum regularization

International Nuclear Information System (INIS)

Halpern, M.B.

1987-03-01

This lecture is primarily an introduction to coordinate-invariant regularization, a recent advance in the continuum regularization program. In this context, the program is seen as fundamentally geometric, with all regularization contained in regularized DeWitt superstructures on field deformations

Interaction between polymorphisms in aspirin metabolic pathways, regular aspirin use and colorectal cancer risk: A case-control study in unselected white European populations.

Directory of Open Access Journals (Sweden)

Harsh Sheth

Full Text Available Regular aspirin use is associated with reduced risk of colorectal cancer (CRC. Variation in aspirin's chemoprevention efficacy has been attributed to the presence of single nucleotide polymorphisms (SNPs. We conducted a meta-analysis using two large population-based case-control datasets, the UK-Leeds Colorectal Cancer Study Group and the NIH-Colon Cancer Family Registry, having a combined total of 3325 cases and 2262 controls. The aim was to assess 42 candidate SNPs in 15 genes whose association with colorectal cancer risk was putatively modified by aspirin use, in the literature. Log odds ratios (ORs and standard errors were estimated for each dataset separately using logistic regression adjusting for age, sex and study site, and dataset-specific results were combined using random effects meta-analysis. Meta-analysis showed association between SNPs rs6983267, rs11694911 and rs2302615 with CRC risk reduction (All P<0.05. Association for SNP rs6983267 in the CCAT2 gene only was noteworthy after multiple test correction (P = 0.001. Site-specific analysis showed association between SNPs rs1799853 and rs2302615 with reduced colon cancer risk only (P = 0.01 and P = 0.004, respectively, however neither reached significance threshold following multiple test correction. Meta-analysis of SNPs rs2070959 and rs1105879 in UGT1A6 gene showed interaction between aspirin use and CRC risk (Pinteraction = 0.01 and 0.02, respectively; stratification by aspirin use showed an association for decreased CRC risk for aspirin users having a wild-type genotype (rs2070959 OR = 0.77, 95% CI = 0.68-0.86; rs1105879 OR = 0.77 95% CI = 0.69-0.86 compared to variant allele cariers. The direction of the interaction however is in contrast to that published in studies on colorectal adenomas. Both SNPs showed potential site-specific interaction with aspirin use and colon cancer risk only (Pinteraction = 0.006 and 0.008, respectively, with the direction of association similar to

Class of regular bouncing cosmologies

Science.gov (United States)

Vasilić, Milovan

2017-06-01

In this paper, I construct a class of everywhere regular geometric sigma models that possess bouncing solutions. Precisely, I show that every bouncing metric can be made a solution of such a model. My previous attempt to do so by employing one scalar field has failed due to the appearance of harmful singularities near the bounce. In this work, I use four scalar fields to construct a class of geometric sigma models which are free of singularities. The models within the class are parametrized by their background geometries. I prove that, whatever background is chosen, the dynamics of its small perturbations is classically stable on the whole time axis. Contrary to what one expects from the structure of the initial Lagrangian, the physics of background fluctuations is found to carry two tensor, two vector, and two scalar degrees of freedom. The graviton mass, which naturally appears in these models, is shown to be several orders of magnitude smaller than its experimental bound. I provide three simple examples to demonstrate how this is done in practice. In particular, I show that graviton mass can be made arbitrarily small.

Regular expression containment

DEFF Research Database (Denmark)

Henglein, Fritz; Nielsen, Lasse

2011-01-01

We present a new sound and complete axiomatization of regular expression containment. It consists of the conventional axiomatiza- tion of concatenation, alternation, empty set and (the singleton set containing) the empty string as an idempotent semiring, the fixed- point rule E* = 1 + E × E......* for Kleene-star, and a general coin- duction rule as the only additional rule. Our axiomatization gives rise to a natural computational inter- pretation of regular expressions as simple types that represent parse trees, and of containment proofs as coercions. This gives the axiom- atization a Curry......-Howard-style constructive interpretation: Con- tainment proofs do not only certify a language-theoretic contain- ment, but, under our computational interpretation, constructively transform a membership proof of a string in one regular expres- sion into a membership proof of the same string in another regular expression. We...

Supersymmetric dimensional regularization

International Nuclear Information System (INIS)

Siegel, W.; Townsend, P.K.; van Nieuwenhuizen, P.

1980-01-01

There is a simple modification of dimension regularization which preserves supersymmetry: dimensional reduction to real D < 4, followed by analytic continuation to complex D. In terms of component fields, this means fixing the ranges of all indices on the fields (and therefore the numbers of Fermi and Bose components). For superfields, it means continuing in the dimensionality of x-space while fixing the dimensionality of theta-space. This regularization procedure allows the simple manipulation of spinor derivatives in supergraph calculations. The resulting rules are: (1) First do all algebra exactly as in D = 4; (2) Then do the momentum integrals as in ordinary dimensional regularization. This regularization procedure needs extra rules before one can say that it is consistent. Such extra rules needed for superconformal anomalies are discussed. Problems associated with renormalizability and higher order loops are also discussed

Self-interacting inelastic dark matter: a viable solution to the small scale structure problems

Energy Technology Data Exchange (ETDEWEB)

Blennow, Mattias; Clementz, Stefan; Herrero-Garcia, Juan, E-mail: emb@kth.se, E-mail: scl@kth.se, E-mail: juan.herrero-garcia@adelaide.edu.au [Department of Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, 106 91 Stockholm (Sweden)

2017-03-01

Self-interacting dark matter has been proposed as a solution to the small-scale structure problems, such as the observed flat cores in dwarf and low surface brightness galaxies. If scattering takes place through light mediators, the scattering cross section relevant to solve these problems may fall into the non-perturbative regime leading to a non-trivial velocity dependence, which allows compatibility with limits stemming from cluster-size objects. However, these models are strongly constrained by different observations, in particular from the requirements that the decay of the light mediator is sufficiently rapid (before Big Bang Nucleosynthesis) and from direct detection. A natural solution to reconcile both requirements are inelastic endothermic interactions, such that scatterings in direct detection experiments are suppressed or even kinematically forbidden if the mass splitting between the two-states is sufficiently large. Using an exact solution when numerically solving the Schrödinger equation, we study such scenarios and find regions in the parameter space of dark matter and mediator masses, and the mass splitting of the states, where the small scale structure problems can be solved, the dark matter has the correct relic abundance and direct detection limits can be evaded.

Regularized Label Relaxation Linear Regression.

Science.gov (United States)

Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

2018-04-01

Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

Global Classical Solutions for Partially Dissipative Hyperbolic System of Balance Laws

Science.gov (United States)

Xu, Jiang; Kawashima, Shuichi

2014-02-01

The basic existence theory of Kato and Majda enables us to obtain local-in-time classical solutions to generally quasilinear hyperbolic systems in the framework of Sobolev spaces (in x) with higher regularity. However, it remains a challenging open problem whether classical solutions still preserve well-posedness in the case of critical regularity. This paper is concerned with partially dissipative hyperbolic system of balance laws. Under the entropy dissipative assumption, we establish the local well-posedness and blow-up criterion of classical solutions in the framework of Besov spaces with critical regularity with the aid of the standard iteration argument and Friedrichs' regularization method. Then we explore the theory of function spaces and develop an elementary fact that indicates the relation between homogeneous and inhomogeneous Chemin-Lerner spaces (mixed space-time Besov spaces). This fact allows us to capture the dissipation rates generated from the partial dissipative source term and further obtain the global well-posedness and stability by assuming at all times the Shizuta-Kawashima algebraic condition. As a direct application, the corresponding well-posedness and stability of classical solutions to the compressible Euler equations with damping are also obtained.

Interaction debugging : an integral approach to analyze human-robot interaction

NARCIS (Netherlands)

Kooijmans, T.; Kanda, T.; Bartneck, C.; Ishiguro, H.; Hagita, N.

2006-01-01

Along with the development of interactive robots, controlled experiments and field trials are regularly conducted to stage human-robot interaction. Experience in this field has shown that analyzing human-robot interaction for evaluation purposes fosters the development of improved systems and the

Ab initio modeling of interactions between screw dislocations and interstitial solutes in body-centered cubic transition metals

International Nuclear Information System (INIS)

Luthi, Berengere

2017-01-01

In order to improve our understanding of alloy plasticity, it is important to describe at the atomic scale the dislocation-solute interactions and their effect on the dislocation mobility. This work focuses on the body-centered cubic (BCC) transition metals in presence of interstitial solute atoms, in particular the Fe-C system. Using Density Functional Theory (DFT) calculations, the core structure of the screw dislocation of Burgers vector b=1/2<111> was investigated in iron in presence of boron, carbon, nitrogen and oxygen solute atoms, and in BCC metals from group 5 (V, Nb, Ta) and 6 (Mo, W) in presence of carbon solutes. A core reconstruction is evidenced in iron and group 6 metals, along with a strong attractive dislocation-solute interaction energy: the dislocation goes from easy to hard configuration where the solute atoms are at the center of trigonal prisms along the dislocation line. A different behavior is observed in group 5 metals, for which the most stable configuration for the carbon atom is an octahedral site in the vicinity of the dislocation, without any core reconstruction. This group tendency is linked to the structure of mono-carbides. Consequences of the strongly attractive dislocation-solute interactions in Fe(C) were then investigated. First the equilibrium segregation close to the dislocation core was studied using a mean-field model and Monte Carlo simulations. Over a wide temperature range, from 200 to 700 K, a strong segregation is predicted with every other prismatic site occupied by a carbon atom. Then, the mobility of the dislocation in presence of carbon atoms was investigated by modeling the double-kink mechanism with DFT, in relation with experimental data obtained with transmission electron microscopy. The activation energy obtained for this atomic scale mechanism is in good agreement with experimental values for the dynamic strain aging. (author) [fr

Graph Regularized Auto-Encoders for Image Representation.

Science.gov (United States)

Yiyi Liao; Yue Wang; Yong Liu

2017-06-01

Image representation has been intensively explored in the domain of computer vision for its significant influence on the relative tasks such as image clustering and classification. It is valuable to learn a low-dimensional representation of an image which preserves its inherent information from the original image space. At the perspective of manifold learning, this is implemented with the local invariant idea to capture the intrinsic low-dimensional manifold embedded in the high-dimensional input space. Inspired by the recent successes of deep architectures, we propose a local invariant deep nonlinear mapping algorithm, called graph regularized auto-encoder (GAE). With the graph regularization, the proposed method preserves the local connectivity from the original image space to the representation space, while the stacked auto-encoders provide explicit encoding model for fast inference and powerful expressive capacity for complex modeling. Theoretical analysis shows that the graph regularizer penalizes the weighted Frobenius norm of the Jacobian matrix of the encoder mapping, where the weight matrix captures the local property in the input space. Furthermore, the underlying effects on the hidden representation space are revealed, providing insightful explanation to the advantage of the proposed method. Finally, the experimental results on both clustering and classification tasks demonstrate the effectiveness of our GAE as well as the correctness of the proposed theoretical analysis, and it also suggests that GAE is a superior solution to the current deep representation learning techniques comparing with variant auto-encoders and existing local invariant methods.

Stress, strain, and structural dynamics an interactive handbook of formulas, solutions, and Matlab toolboxes

CERN Document Server

Yang, Bingen

2005-01-01

Stress, Strain, and Structural Dynamics is a comprehensive and definitive reference to statics and dynamics of solids and structures, including mechanics of materials, structural mechanics, elasticity, rigid-body dynamics, vibrations, structural dynamics, and structural controls. This text integrates the development of fundamental theories, formulas and mathematical models with user-friendly interactive computer programs, written in the powerful and popular MATLAB. This unique merger of technical referencing and interactive computing allows instant solution of a variety of engineering problems

Regularization by External Variables

DEFF Research Database (Denmark)

Bossolini, Elena; Edwards, R.; Glendinning, P. A.

2016-01-01

Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind of regula......Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind...

Regular Single Valued Neutrosophic Hypergraphs

Directory of Open Access Journals (Sweden)

Muhammad Aslam Malik

2016-12-01

Full Text Available In this paper, we define the regular and totally regular single valued neutrosophic hypergraphs, and discuss the order and size along with properties of regular and totally regular single valued neutrosophic hypergraphs. We also extend work on completeness of single valued neutrosophic hypergraphs.

Caffeine and sugars interact in aqueous solutions: a simulation and NMR study.

Science.gov (United States)

Tavagnacco, Letizia; Engström, Olof; Schnupf, Udo; Saboungi, Marie-Louise; Himmel, Michael; Widmalm, Göran; Cesàro, Attilio; Brady, John W

2012-09-27

Molecular dynamics simulations were carried out on several systems of caffeine interacting with simple sugars. These included a single caffeine molecule in a 3 m solution of α-D-glucopyranose, at a caffeine concentration of 0.083 m, a single caffeine in a 3 m solution of β-D-glucopyranose, and a single caffeine molecule in a 1.08 m solution of sucrose (table sugar). Parallel nuclear magnetic resonance titration experiments were carried out on the same solutions under similar conditions. Consistent with previous thermodynamic experiments, the sugars were found to have an affinity for the caffeine molecules in both the simulations and experiments, and the binding in these complexes occurs by face-to-face stacking of the hydrophobic triad of protons of the pyranose rings against the caffeine face, rather than by hydrogen bonding. For the disaccharide, the binding occurs via stacking of the glucose ring against the caffeine, with a lesser affinity for the fructose observed. These findings are consistent with the association being driven by hydrophobic hydration and are similar to the previously observed binding of glucose rings to various other planar molecules, including indole, serotonin, and phenol.

Interactions between fluorinated cationic guar gum and surfactants in the dilute and semi-dilute solutions.

Science.gov (United States)

Wang, Chen; Li, Xiaorui; Li, Peizhi; Niu, Yuhua

2014-01-01

The interactions between the fluorinated cationic guar gum (FCGG) and ionic surfactants including cetyl trimethyl ammonium bromide (CTAB) and sodium lauryl sulfate (SDS) were studied by light scattering, fluorescence spectroscopy, UV-spectrophotometer, (19)F NMR and dynamic rheometer, respectively. The FCGG is prepared with cationic guar gum, isophorone diisocyanate and 2,2,3,4,4,4-hexafluoro-1-butanol. The results show that, with the addition of the surfactants, the stretching degree of the FCGG chains is increased in the FCGG/CTAB solutions, while the dramatical shrinking of FCGG chain, the phase separation and the re-stretched macromolecules appear successively because of the electricity neutralization reaction in the FCGG/SDS system. The mixed hydrophobic domains in all solutions will be reinforced and then dismantled. The solution elasticity shows up the maximum value accordingly. The surfactants can be embedded in the micro-domains and then hinder the fluorinated segmental motions. The interactions between FCGG and SDS are much stronger than those between FCGG and CTAB. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sparsity regularization for parameter identification problems

International Nuclear Information System (INIS)

Jin, Bangti; Maass, Peter

2012-01-01

The investigation of regularization schemes with sparsity promoting penalty terms has been one of the dominant topics in the field of inverse problems over the last years, and Tikhonov functionals with ℓ p -penalty terms for 1 ⩽ p ⩽ 2 have been studied extensively. The first investigations focused on regularization properties of the minimizers of such functionals with linear operators and on iteration schemes for approximating the minimizers. These results were quickly transferred to nonlinear operator equations, including nonsmooth operators and more general function space settings. The latest results on regularization properties additionally assume a sparse representation of the true solution as well as generalized source conditions, which yield some surprising and optimal convergence rates. The regularization theory with ℓ p sparsity constraints is relatively complete in this setting; see the first part of this review. In contrast, the development of efficient numerical schemes for approximating minimizers of Tikhonov functionals with sparsity constraints for nonlinear operators is still ongoing. The basic iterated soft shrinkage approach has been extended in several directions and semi-smooth Newton methods are becoming applicable in this field. In particular, the extension to more general non-convex, non-differentiable functionals by variational principles leads to a variety of generalized iteration schemes. We focus on such iteration schemes in the second part of this review. A major part of this survey is devoted to applying sparsity constrained regularization techniques to parameter identification problems for partial differential equations, which we regard as the prototypical setting for nonlinear inverse problems. Parameter identification problems exhibit different levels of complexity and we aim at characterizing a hierarchy of such problems. The operator defining these inverse problems is the parameter-to-state mapping. We first summarize some

Critical phenomena of regular black holes in anti-de Sitter space-time

Energy Technology Data Exchange (ETDEWEB)

Fan, Zhong-Ying [Peking University, Center for High Energy Physics, Beijing (China)

2017-04-15

In General Relativity, addressing coupling to a non-linear electromagnetic field, together with a negative cosmological constant, we obtain the general static spherical symmetric black hole solution with magnetic charges, which is asymptotic to anti-de Sitter (AdS) space-times. In particular, for a degenerate case the solution becomes a Hayward-AdS black hole, which is regular everywhere in the full space-time. The existence of such a regular black hole solution preserves the weak energy condition, while the strong energy condition is violated. We then derive the first law and the Smarr formula of the black hole solution. We further discuss its thermodynamic properties and study the critical phenomena in the extended phase space where the cosmological constant is treated as a thermodynamic variable as well as the parameter associated with the non-linear electrodynamics. We obtain many interesting results such as: the Maxwell equal area law in the P-V (or S-T) diagram is violated and consequently the critical point (T{sub *},P{sub *}) of the first order small-large black hole transition does not coincide with the inflection point (T{sub c},P{sub c}) of the isotherms; the Clapeyron equation describing the coexistence curve of the Van der Waals (vdW) fluid is no longer valid; the heat capacity at constant pressure is finite at the critical point; the various exponents near the critical point are also different from those of the vdW fluid. (orig.)

A dynamical regularization algorithm for solving inverse source problems of elliptic partial differential equations

Science.gov (United States)

Zhang, Ye; Gong, Rongfang; Cheng, Xiaoliang; Gulliksson, Mårten

2018-06-01

This study considers the inverse source problem for elliptic partial differential equations with both Dirichlet and Neumann boundary data. The unknown source term is to be determined by additional boundary conditions. Unlike the existing methods found in the literature, which usually employ the first-order in time gradient-like system (such as the steepest descent methods) for numerically solving the regularized optimization problem with a fixed regularization parameter, we propose a novel method with a second-order in time dissipative gradient-like system and a dynamical selected regularization parameter. A damped symplectic scheme is proposed for the numerical solution. Theoretical analysis is given for both the continuous model and the numerical algorithm. Several numerical examples are provided to show the robustness of the proposed algorithm.

Interaction between Al3+ and acrylic acid and polyacrylic acid in acidic aqueous solution: a model experiment for the behavior of Al3+ in acidified soil solution.

Science.gov (United States)

Etou, Mayumi; Masaki, Yuka; Tsuji, Yutaka; Saito, Tomoyuki; Bai, Shuqin; Nishida, Ikuko; Okaue, Yoshihiro; Yokoyama, Takushi

2011-01-01

From the viewpoint of the phytotoxicity and mobility of Al(3+) released from soil minerals due to soil acidification, the interaction between Al(3+) and acrylic acid (AA) and polyacrylic acid (PAA) as a model compound of fulvic acid was investigated. The interaction was examined at pH 3 so as to avoid the hydrolysis of Al(3+). The interaction between Al(3+) and AA was weak. However, the interaction between Al(3+) and PAA was strong and depended on the initial (COOH in PAA)/Al molar ratio (R(P)) of the solution. For the range of 1/R(P), the interaction between Al(3+) and PAA can be divided into three categories: (1) 1:1 Al-PAA-complex (an Al(3+) combines to a carboxyl group), (2) intermolecular Al-PAA-complex (an Al(3+) combines to more than 2 carboxyl groups of other Al-PAA-complexes) in addition to the 1:1 Al-PAA-complex and (3) precipitation of intermolecular complexes. In conclusion, R(P) is an important factor affecting the behavior of Al(3+) in acidic soil solution.

A regularization method for solving the Poisson equation for mixed unbounded-periodic domains

DEFF Research Database (Denmark)

Spietz, Henrik Juul; Mølholm Hejlesen, Mads; Walther, Jens Honoré

2018-01-01

the regularized unbounded-periodic Green's functions can be implemented in an FFT-based Poisson solver to obtain a convergence rate corresponding to the regularization order of the Green's function. The high order is achieved without any additional computational cost from the conventional FFT-based Poisson solver...... and enables the calculation of the derivative of the solution to the same high order by direct spectral differentiation. We illustrate an application of the FFT-based Poisson solver by using it with a vortex particle mesh method for the approximation of incompressible flow for a problem with a single periodic...

Virtual in Real. Interactive Solutions for Learning and Communication in the National Archaeological Museum of Marche

Science.gov (United States)

Clini, P.; Nespeca, R.; Ruggeri, L.

2017-05-01

Today the ICTs are favourable additions to museum exhibitions. This work aims to realize an innovative system of digital exploitation of artefacts in the National Archaeological Museum of Marche (MANaM), in order to create a shared museum that will improve the knowledge of cultural contents through the paradigm "learning by interacting" and "edutainment". The main novelty is the implementation of stand-alone multimedia installations for digital artefacts that combine real and virtual scenarios in order to enrich the experience, the knowledge and the multi-sensory perception. A Digital Library (DL) is created using Close Range Photogrammetry (CRP) techniques applied to 21 archaeological artefacts belonging to different categories. Enriched with other data (texts, images, multimedia), all 3D models flow into the cloud data server from which are recalled in the individual exhibitions. In particular, we have chosen three types of technological solutions: VISUAL, TACTILE, SPATIAL. All the solutions take into account the possibility of group interaction, allowing the participation of the interaction to an appropriate number of users. Sharing the experience enables greater involvement, generating communicative effectiveness much higher than it would get from a lonely visit. From the "Museum Visitors Behaviour Analysis" we obtain a survey about users' needs and efficiency of the interactive solutions. The main result of this work is the educational impact in terms of increase in visitors, specially students, learning increase of historical and cultural content, greater user involvement during the visit to the museum.

Family socialization of adolescent's self-reported cigarette use: the role of parents' history of regular smoking and parenting style.

Science.gov (United States)

Foster, Sarah E; Jones, Deborah J; Olson, Ardis L; Forehand, Rex; Gaffney, Cecelia A; Zens, Michael S; Bau, J J

2007-05-01

To examine the main and interactive effects of parental history of regular cigarette smoking and parenting style on adolescent self-reported cigarette use. Predictors of adolescent self-reported cigarette use, including parents' history of regular cigarette smoking and two dimensions of parenting behavior, were analyzed in a sample of 934 predominately Caucasian (96.3%) parent-adolescent dyads. Families were drawn from the control group of a randomized control trial aimed at preventing adolescent substance use. In addition to the main effects of parents' history of regular smoking and parental warmth, logistic regression analysis revealed that the interaction of these two variables was associated with adolescent self-reported cigarette use. Parental warmth was associated with a decreased likelihood of the adolescent ever having smoked a cigarette; however, this was true only if neither parent had a history of regular cigarette smoking. Findings suggest that adolescent smoking prevention programs may be more efficacious if they address both parental history of regular smoking and parenting behavior.

Regularization by fractional filter methods and data smoothing

International Nuclear Information System (INIS)

Klann, E; Ramlau, R

2008-01-01

This paper is concerned with the regularization of linear ill-posed problems by a combination of data smoothing and fractional filter methods. For the data smoothing, a wavelet shrinkage denoising is applied to the noisy data with known error level δ. For the reconstruction, an approximation to the solution of the operator equation is computed from the data estimate by fractional filter methods. These fractional methods are based on the classical Tikhonov and Landweber method, but avoid, at least partially, the well-known drawback of oversmoothing. Convergence rates as well as numerical examples are presented

Thermodynamic Product Relations for Generalized Regular Black Hole

International Nuclear Information System (INIS)

Pradhan, Parthapratim

2016-01-01

We derive thermodynamic product relations for four-parametric regular black hole (BH) solutions of the Einstein equations coupled with a nonlinear electrodynamics source. The four parameters can be described by the mass (m), charge (q), dipole moment (α), and quadrupole moment (β), respectively. We study its complete thermodynamics. We compute different thermodynamic products, that is, area product, BH temperature product, specific heat product, and Komar energy product, respectively. Furthermore, we show some complicated function of horizon areas that is indeed mass-independent and could turn out to be universal.

A splitting algorithm for directional regularization and sparsification

DEFF Research Database (Denmark)

Rakêt, Lars Lau; Nielsen, Mads

2012-01-01

We present a new split-type algorithm for the minimization of a p-harmonic energy with added data fidelity term. The half-quadratic splitting reduces the original problem to two straightforward problems, that can be minimized efficiently. The minimizers to the two sub-problems can typically...... be computed pointwise and are easily implemented on massively parallel processors. Furthermore the splitting method allows for the computation of solutions to a large number of more advanced directional regularization problems. In particular we are able to handle robust, non-convex data terms, and to define...

SAR image regularization with fast approximate discrete minimization.

Science.gov (United States)

Denis, Loïc; Tupin, Florence; Darbon, Jérôme; Sigelle, Marc

2009-07-01

Synthetic aperture radar (SAR) images, like other coherent imaging modalities, suffer from speckle noise. The presence of this noise makes the automatic interpretation of images a challenging task and noise reduction is often a prerequisite for successful use of classical image processing algorithms. Numerous approaches have been proposed to filter speckle noise. Markov random field (MRF) modelization provides a convenient way to express both data fidelity constraints and desirable properties of the filtered image. In this context, total variation minimization has been extensively used to constrain the oscillations in the regularized image while preserving its edges. Speckle noise follows heavy-tailed distributions, and the MRF formulation leads to a minimization problem involving nonconvex log-likelihood terms. Such a minimization can be performed efficiently by computing minimum cuts on weighted graphs. Due to memory constraints, exact minimization, although theoretically possible, is not achievable on large images required by remote sensing applications. The computational burden of the state-of-the-art algorithm for approximate minimization (namely the alpha -expansion) is too heavy specially when considering joint regularization of several images. We show that a satisfying solution can be reached, in few iterations, by performing a graph-cut-based combinatorial exploration of large trial moves. This algorithm is applied to joint regularization of the amplitude and interferometric phase in urban area SAR images.

Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

International Nuclear Information System (INIS)

Shimizu, S.; Kurita, K.; Furusaka, M.

2002-01-01

Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

On a correspondence between regular and non-regular operator monotone functions

DEFF Research Database (Denmark)

Gibilisco, P.; Hansen, Frank; Isola, T.

2009-01-01

We prove the existence of a bijection between the regular and the non-regular operator monotone functions satisfying a certain functional equation. As an application we give a new proof of the operator monotonicity of certain functions related to the Wigner-Yanase-Dyson skew information....

The Interaction of Sorbitol with Caffeine in Aqueous Solution.

Science.gov (United States)

Tavagnacco, Letizia; Brady, John W; Cesàro, Attilio

2013-09-01

Molecular dynamics simulations were carried out on a system of caffeine interacting with the sugar alcohol sorbitol. The system examined had a caffeine concentration 0.083 m and a sugar concentration 1.08 m. The trajectories of all molecules in the system were collected over a period of 80 ns and analyzed to determine whether there is any tendency for sorbitol to bind to caffeine, and if so, by what mechanism. The results show that the sorbitol molecules have an affinity for the caffeine molecules and that the binding occurred by the interaction of the aliphatic hydrophobic protons of the sugar with the caffeine face. This intermolecular association via face-to-face stacking, as suggested by simulation studies, is similar to that found for sucrose and for D-glucose, which overwhelmingly exists in the pyranose ring chair form in aqueous solution, as well as for caffeine-caffeine association. The sorbitol molecules, however, exist as relatively extended chains and are, therefore, topologically quite different from the sugars sucrose and glucose. The comparison of the average conformation of sorbitol molecules bound to caffeine with that of molecules in the free state shows a substantial similarity.

On the role of specific interactions in the diffusion of nanoparticles in aqueous polymer solutions.

Science.gov (United States)

Mun, Ellina A; Hannell, Claire; Rogers, Sarah E; Hole, Patrick; Williams, Adrian C; Khutoryanskiy, Vitaliy V

2014-01-14

Understanding nanoparticle diffusion within non-Newtonian biological and synthetic fluids is essential in designing novel formulations (e.g., nanomedicines for drug delivery, shampoos, lotions, coatings, paints, etc.), but is presently poorly defined. This study reports the diffusion of thiolated and PEGylated silica nanoparticles, characterized by small-angle neutron scattering, in solutions of various water-soluble polymers such as poly(acrylic acid) (PAA), poly(N-vinylpyrrolidone) (PVP), poly(ethylene oxide) (PEO), and hydroxyethylcellulose (HEC) probed using NanoSight nanoparticle tracking analysis. Results show that the diffusivity of nanoparticles is affected by their dimensions, medium viscosity, and, in particular, the specific interactions between nanoparticles and the macromolecules in solution; strong attractive interactions such as hydrogen bonding hamper diffusion. The water-soluble polymers retarded the diffusion of thiolated particles in the order PEO > PVP > PAA > HEC whereas for PEGylated silica particles retardation followed the order PAA > PVP = HEC > PEO. In the absence of specific interactions with the medium, PEGylated nanoparticles exhibit enhanced mobility compared to their thiolated counterparts despite some increase in their dimensions.

Interaction of radiation-generated radicals with myoglobin in aqueous solution

International Nuclear Information System (INIS)

Whitburn, K.D.; Hoffman, M.Z.

1985-01-01

The γ-radiolysis of aqueous solutions of ferrimyoglobin in the presence of N 2 O at pH 7.3 has been examined as a function of added catalase and oxygen. Changes in the nature of the heme group have been monitored by visible absorption spectrophotometry and analysed quantitatively by a multiple wavelength method based on Beer's Law. Simple chemical analyses have been used to confirm qualitative identification of the product derivatives. As observed previously, the ferriheme is reduced by indirect globin-mediated action initiated by radical OH/H radical. The yield of reduced product decreases as [O 2 ] derived from irradiated water and from protein-mediated processes in oxygenated solution, is eliminated by the presence of catalase. Formation of a hemichrome form of ferrimyoglobin is apparent at higher doses in the presence of O 2 . These results demonstrate that oxygen plays an important role in controlling the nature and extent of redox that manifests ultimately on the heme group of ferrimyoglobin as a result of the initial interaction of radical OH/H radical. (author)

Stochastic analytic regularization

International Nuclear Information System (INIS)

Alfaro, J.

1984-07-01

Stochastic regularization is reexamined, pointing out a restriction on its use due to a new type of divergence which is not present in the unregulated theory. Furthermore, we introduce a new form of stochastic regularization which permits the use of a minimal subtraction scheme to define the renormalized Green functions. (author)

1D and 2D NMR Spectroscopy of Bonding Interactions within Stable and Phase-Separating Organic Electrolyte-Cellulose Solutions.

Science.gov (United States)

Clough, Matthew T; Farès, Christophe; Rinaldi, Roberto

2017-09-11

Organic electrolyte solutions (i.e. mixtures containing an ionic liquid and a polar, molecular co-solvent) are highly versatile solvents for cellulose. However, the underlying solvent-solvent and solvent-solute interactions are not yet fully understood. Herein, mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate, the co-solvent 1,3-dimethyl-2-imidazolidinone, and cellulose are investigated using 1D and 2D NMR spectroscopy. The use of a triply- 13 C-labelled ionic liquid enhances the signal-to-noise ratio for 13 C NMR spectroscopy, enabling changes in bonding interactions to be accurately pinpointed. Current observations reveal an additional degree of complexity regarding the distinct roles of cation, anion, and co-solvent toward maintaining cellulose solubility and phase stability. Unexpectedly, the interactions between the dialkylimidazolium ring C 2 -H substituent and cellulose become more pronounced at high temperatures, counteracted by a net weakening of acetate-cellulose interactions. Moreover, for mixtures that exhibit critical solution behavior, phase separation is accompanied by the apparent recombination of cation-anion pairs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interactions of glutamine dipeptides with sodium dodecyl sulfate in aqueous solution measured by volume, conductivity, and fluorescence spectra

Energy Technology Data Exchange (ETDEWEB)

Yan Zhenning, E-mail: yanzzn@zzu.edu.cn [Department of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001 (China); Sun Ximeng; Li Weiwei; Li Yu [Department of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001 (China); Wang Jianji [Department of Chemistry, Henan Normal University, Xinxiang, Henan 453007 (China)

2011-10-15

Highlights: > Ion-ion and ion-polar group interactions are dominant interactions. > The SDS addition and temperature increase cause a dehydration effect on dipeptides. > The addition of dipeptide in water decreases the c{sub cmc} of SDS. > Enthalpy-entropy compensation takes place during micellization. > Micelle aggregation number was decreased by addition of glutamine dipeptides. - Abstract: Densities, conductivities, and fluorescence spectra of {l_brace}sodium dodecyl sulfate (SDS) + glutamine dipeptide + water{r_brace} mixtures were measured as a function of temperature. The density data have been utilized to calculate apparent molar volumes, standard partial molar volumes (V{sub 2,{phi}}{sup o}), standard partial molar volumes of transfer from water to aqueous SDS solutions ({Delta}{sub t}V{sup o}), the hydration number, partial molar expansibility (E{sub {phi}}{sup o}), and Hepler's constant of glutamine dipeptides. The critical micellar concentration (c{sub cmc}) and the degree of counterion dissociation of SDS micelles obtained from electrical conductivity data have been estimated at various concentrations of glutamine dipeptide. Thermodynamic parameters of micellization of SDS in aqueous dipeptide solutions have been determined from c{sub cmc} values and an enthalpy-entropy compensation effect was observed for the ternary systems. The pyrene fluorescence spectra were used to study the change of micropolarity produced by the interaction of SDS with glutamine dipeptide, and the aggregation behavior of SDS. The results have been interpreted in terms of solute-solvent interactions and structural changes in the mixed solutions.

Ascorbic Acid and BSA Protein in Solution and Films: Interaction and Surface Morphological Structure

Directory of Open Access Journals (Sweden)

Rafael R. G. Maciel

2013-01-01

Full Text Available This paper reports on the study of the interactions between ascorbic acid (AA and bovine serum albumin (BSA in aqueous solution as well as in films (BSA/AA films prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, , determined for aggregates from BSA and AA was found to be about 102 M−1, which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state.

One pot obtention of a tetrabutylammonium hydroxide solution for ironporphyrin-OH- interaction studies in organic solvents

Directory of Open Access Journals (Sweden)

Lídia S. Iwamoto

1999-04-01

Full Text Available In this work we report the obtention of a tetrabutylammonium hydroxide (TBAOH solution in acetonitrile in a one pot process in order to study the interaction ironporphyrinOH- in non-aqueous systems. All the reactions were carried out under dry argon atmosphere to prevent the contamination of the solution with CO2, which leads to the formation of (TBA2CO3.

Image super-resolution reconstruction based on regularization technique and guided filter

Science.gov (United States)

Huang, De-tian; Huang, Wei-qin; Gu, Pei-ting; Liu, Pei-zhong; Luo, Yan-min

2017-06-01

In order to improve the accuracy of sparse representation coefficients and the quality of reconstructed images, an improved image super-resolution algorithm based on sparse representation is presented. In the sparse coding stage, the autoregressive (AR) regularization and the non-local (NL) similarity regularization are introduced to improve the sparse coding objective function. A group of AR models which describe the image local structures are pre-learned from the training samples, and one or several suitable AR models can be adaptively selected for each image patch to regularize the solution space. Then, the image non-local redundancy is obtained by the NL similarity regularization to preserve edges. In the process of computing the sparse representation coefficients, the feature-sign search algorithm is utilized instead of the conventional orthogonal matching pursuit algorithm to improve the accuracy of the sparse coefficients. To restore image details further, a global error compensation model based on weighted guided filter is proposed to realize error compensation for the reconstructed images. Experimental results demonstrate that compared with Bicubic, L1SR, SISR, GR, ANR, NE + LS, NE + NNLS, NE + LLE and A + (16 atoms) methods, the proposed approach has remarkable improvement in peak signal-to-noise ratio, structural similarity and subjective visual perception.

Evaluation of a dual-room sliding gantry CT concept for workflow optimisation in polytrauma and regular in- and outpatient management

Energy Technology Data Exchange (ETDEWEB)

Frellesen, Claudia; Boettcher, Marie; Wichmann, Julian L.; Drieske, Martina; Kerl, J. Matthias; Lehnert, Thomas [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany); Nau, Christoph; Geiger, Emmanuel; Wutzler, Sebastian [Department of Trauma, Reconstructive and Hand Surgery, Clinic of the Goethe University, Frankfurt (Germany); Ackermann, Hanns [Department of Biostatistics and Mathematical Modelling, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J. [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany); Bauer, Ralf W., E-mail: ralfwbauer@aol.com [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany)

2015-01-15

Highlights: • A sliding gantry trauma room CT solution facilitates significantly faster polytrauma management. • Faster and more efficient resumption of regularly scheduled patients due to a two room solution is supported. • Sliding gantry CT achieves the same patient throughput as two separate conventional CT devices. - Abstract: Objectives: To reveal the impact on workflow from introducing a dual-room sliding gantry CT to the trauma room for polytrauma and regularly scheduled in- outpatients with regard to efficiency and degree of capacity utilisation. Materials and methods: Time analysis was performed for 30 polytrauma patients each in 2 different trauma room settings, the new trauma room comprising a sliding gantry CT, the old one a stationary single-room CT. Complete trauma room and diagnostic workup times were manually measured and compared for both groups. In a third scenario, the number of CT scans performed with one single sliding gantry CT and the two-room concept was compared to the number of CT scans performed on two separate regular CT units in a 5 days clinical routine sample. Results: Patients demographics and type of CT examinations were comparable for all patient groups. The median time from patient arrival in the trauma room until beginning of CT scanning was 6 min shorter for the sliding gantry CT group (21 vs.15 min). Sliding gantry CT embedded in a two-room solution achieved 252 CT scans in 5 working days, compared to 250 CT scans on two separate regular CT units with the same man power. Conclusions: Sliding gantry CT in the trauma room allows for significant time saving in the diagnostic workup of polytrauma patients and faster resumption of the regular in- outpatient's CT schedule is possible. With the same man power, the dual-room solution is able to generate the same throughput as two separate CT units.

Evaluation of a dual-room sliding gantry CT concept for workflow optimisation in polytrauma and regular in- and outpatient management

International Nuclear Information System (INIS)

Frellesen, Claudia; Boettcher, Marie; Wichmann, Julian L.; Drieske, Martina; Kerl, J. Matthias; Lehnert, Thomas; Nau, Christoph; Geiger, Emmanuel; Wutzler, Sebastian; Ackermann, Hanns; Vogl, Thomas J.; Bauer, Ralf W.

2015-01-01

Highlights: • A sliding gantry trauma room CT solution facilitates significantly faster polytrauma management. • Faster and more efficient resumption of regularly scheduled patients due to a two room solution is supported. • Sliding gantry CT achieves the same patient throughput as two separate conventional CT devices. - Abstract: Objectives: To reveal the impact on workflow from introducing a dual-room sliding gantry CT to the trauma room for polytrauma and regularly scheduled in- outpatients with regard to efficiency and degree of capacity utilisation. Materials and methods: Time analysis was performed for 30 polytrauma patients each in 2 different trauma room settings, the new trauma room comprising a sliding gantry CT, the old one a stationary single-room CT. Complete trauma room and diagnostic workup times were manually measured and compared for both groups. In a third scenario, the number of CT scans performed with one single sliding gantry CT and the two-room concept was compared to the number of CT scans performed on two separate regular CT units in a 5 days clinical routine sample. Results: Patients demographics and type of CT examinations were comparable for all patient groups. The median time from patient arrival in the trauma room until beginning of CT scanning was 6 min shorter for the sliding gantry CT group (21 vs.15 min). Sliding gantry CT embedded in a two-room solution achieved 252 CT scans in 5 working days, compared to 250 CT scans on two separate regular CT units with the same man power. Conclusions: Sliding gantry CT in the trauma room allows for significant time saving in the diagnostic workup of polytrauma patients and faster resumption of the regular in- outpatient's CT schedule is possible. With the same man power, the dual-room solution is able to generate the same throughput as two separate CT units

The Jost function and the S-matrix asymptotic expressions for large complex angular momenta in the presence of central and spin-orbital interaction

International Nuclear Information System (INIS)

Pivovarchik, V.N.; Poplavskij, I.V.

1982-01-01

The asymptotic behaviour of the regular solution, the Yost function and the S-matrix of the Schrodinger equation is estimated by means of WKB quasiclassical method at a fixed physical value of energy (k>0) for lambda→infinity in the domain Re lambda→0 for central and spin-orbital interaction [ru

Strong solutions and instability for the fitness gradient system in evolutionary games between two populations

Science.gov (United States)

Xu, Qiuju; Belmonte, Andrew; deForest, Russ; Liu, Chun; Tan, Zhong

2017-04-01

In this paper, we study a fitness gradient system for two populations interacting via a symmetric game. The population dynamics are governed by a conservation law, with a spatial migration flux determined by the fitness. By applying the Galerkin method, we establish the existence, regularity and uniqueness of global solutions to an approximate system, which retains most of the interesting mathematical properties of the original fitness gradient system. Furthermore, we show that a Turing instability occurs for equilibrium states of the fitness gradient system, and its approximations.

Weakly hydrated surfaces and the binding interactions of small biological solutes.

Science.gov (United States)

Brady, John W; Tavagnacco, Letizia; Ehrlich, Laurent; Chen, Mo; Schnupf, Udo; Himmel, Michael E; Saboungi, Marie-Louise; Cesàro, Attilio

2012-04-01

Extended planar hydrophobic surfaces, such as are found in the side chains of the amino acids histidine, phenylalanine, tyrosine, and tryptophan, exhibit an affinity for the weakly hydrated faces of glucopyranose. In addition, molecular species such as these, including indole, caffeine, and imidazole, exhibit a weak tendency to pair together by hydrophobic stacking in aqueous solution. These interactions can be partially understood in terms of recent models for the hydration of extended hydrophobic faces and should provide insight into the architecture of sugar-binding sites in proteins.

Improving the Performance of Interactive Configuration with Regular String Constraints

DEFF Research Database (Denmark)

Hansen, Esben Rune; Tiedemann, Peter

2008-01-01

A generalization of the problem of interactive configuration has previously been presented in [1]. This generalization utilized decomposition to extend the standard finite domain interactive configuration framework to deal with unbounded string variables and provided features such as prefix auto...

Interactions of U(VI), Nd, and Th(IV) at the Calcite-solution interface

International Nuclear Information System (INIS)

Carroll, S.A.; Dran, J.C.

1992-01-01

The interactions of U(VI), Nd, and Th(IV) at the calcite-solution interface at controlled pCO 2 (g) have been investigated by Rutherford backscattering (RBS), scanning electron microscopy (SEM) and energy dispersive (EDS) analyses of reacted calcite. Uranium precipitation at the calcite-solution interface was observed only for those experiments in which the initial [U(VI)] was greater than the solubility of rutherfordine, UO 2 CO 3 (s). At pH 8.0, flat radial uranium and calcium zoned precipitates form at the mineral-solution interface. At pH 4.3, uranium forms an anastomosing precipitate throughout the calcite surface. RBS analyses confirmed the SEM analyses showing that uranium forms a solid phase within the calcite surface, but formation of an uranium-calcium solid solution at depth is limited. In sharp contrast to U(VI), Nd is concentrated in the solid phase as individual neodymium-calcium carbonate crystals. Calcite and pure orthorhombic neodymium carbonate crystals dissolve at the expense of the formation of a more stable neodymium-calcium solid solution. In the presence of calcite, a thorium-calcium solid solution forms by exchanging Th for Ca in the calcite structure. Thorium precipitates in two linear trends which intersect each other at approximately 105deg C and 75deg C, parallel to calcite rhombohedral cleavage faces. (orig.)

Crystal Nucleation of Tolbutamide in Solution: Relationship to Solvent, Solute Conformation, and Solution Structure.

Science.gov (United States)

Zeglinski, Jacek; Kuhs, Manuel; Khamar, Dikshitkumar; Hegarty, Avril C; Devi, Renuka K; Rasmuson, Åke C

2018-04-03

The influence of the solvent in nucleation of tolbutamide, a medium-sized, flexible and polymorphic organic molecule, has been explored by measuring nucleation induction times, estimating solvent-solute interaction enthalpies using molecular modelling and calorimetric data, probing interactions and clustering with spectroscopy, and modelling solvent-dependence of molecular conformation in solution. The nucleation driving force required to reach the same induction time is strongly solvent-dependent, increasing in the order: acetonitrilenucleation difficulty is a function of the strength of solvent-solute interaction, with emphasis on the interaction with specific H-bonding polar sites of importance in the crystal structure. A clear exception from this rule is the most difficult nucleation in toluene despite the weakest solvent-solute interactions. However molecular dynamics modelling predicts that tolbutamide assumes an intramolecularly H-bonded conformation in toluene, substantially different from and more stable than the conformation in the crystal structure, and thus presenting an additional barrier to nucleation. This explains why nucleation in toluene is the most difficult and why the relatively higher propensity for aggregation of tolbutamide molecules in toluene solution, as observed with FTIR spectroscopy, does not translate into easier nucleation. Thus, our combined experimental and molecular modelling study suggests that the solvent can influence on the nucleation not only via differences in the desolvation but also through the influence on molecular conformation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrating R and Java for Enhancing Interactivity of Algorithmic Data Analysis Software Solutions

Directory of Open Access Journals (Sweden)

Titus Felix FURTUNĂ

2016-06-01

Full Text Available Conceiving software solutions for statistical processing and algorithmic data analysis involves handling diverse data, fetched from various sources and in different formats, and presenting the results in a suggestive, tailorable manner. Our ongoing research aims to design programming technics for integrating R developing environment with Java programming language for interoperability at a source code level. The goal is to combine the intensive data processing capabilities of R programing language, along with the multitude of statistical function libraries, with the flexibility offered by Java programming language and platform, in terms of graphical user interface and mathematical function libraries. Both developing environments are multiplatform oriented, and can complement each other through interoperability. R is a comprehensive and concise programming language, benefiting from a continuously expanding and evolving set of packages for statistical analysis, developed by the open source community. While is a very efficient environment for statistical data processing, R platform lacks support for developing user friendly, interactive, graphical user interfaces (GUIs. Java on the other hand, is a high level object oriented programming language, which supports designing and developing performant and interactive frameworks for general purpose software solutions, through Java Foundation Classes, JavaFX and various graphical libraries. In this paper we treat both aspects of integration and interoperability that refer to integrating Java code into R applications, and bringing R processing sequences into Java driven software solutions. Our research has been conducted focusing on case studies concerning pattern recognition and cluster analysis.

SFAK, Unscattered Gamma Self-Absorption from Regular Fuel Rod Assemblies

International Nuclear Information System (INIS)

Wand, H.

1982-01-01

1 - Description of problem or function: Calculation of the self- absorption of unscattered (gamma-) radiation from fuel assemblies which contain a regular arrangement of identical fuel rods. 2 - Method of solution: The point-kernel is integrated over the radiation sources, i.e. the fuel rods. A uniform mesh of integration points is used for each of the fuel rods. 3 - Restrictions on the complexity of the problem: Number of fuel rods is dynamically allocated

Solution NMR study of the yeast cytochrome c peroxidase: cytochrome c interaction

Energy Technology Data Exchange (ETDEWEB)

Volkov, Alexander N., E-mail: ovolkov@vub.ac.be; Nuland, Nico A. J. van [Vrije Universiteit Brussel, Jean Jeener NMR Centre, Structural Biology Brussels (Belgium)

2013-07-15

Here we present a solution NMR study of the complex between yeast cytochrome c (Cc) and cytochrome c peroxidase (CcP), a paradigm for understanding the biological electron transfer. Performed for the first time, the CcP-observed heteronuclear NMR experiments were used to probe the Cc binding in solution. Combining the Cc- and CcP-detected experiments, the binding interface on both proteins was mapped out, confirming that the X-ray structure of the complex is maintained in solution. Using NMR titrations and chemical shift perturbation analysis, we show that the interaction is independent of the CcP spin-state and is only weakly affected by the Cc redox state. Based on these findings, we argue that the complex of the ferrous Cc and the cyanide-bound CcP is a good mimic of the catalytically-active Cc-CcP compound I species. Finally, no chemical shift perturbations due to the Cc binding at the low-affinity CcP site were observed at low ionic strength. We discuss possible reasons for the absence of the effects and outline future research directions.

Electronic-property dependent interactions between tetracycline and graphene nanomaterials in aqueous solution.

Science.gov (United States)

He, Lin; Liu, Fei-Fei; Zhao, Mengyao; Qi, Zhen; Sun, Xuefei; Afzal, Muhammad Zaheer; Sun, Xiaomin; Li, Yanhui; Hao, Jingcheng; Wang, Shuguang

2018-04-01

Understanding the interactions between graphene nanomaterials (GNMs) and antibiotics in aqueous solution is critical to both the engineering applications of GNMs and the assessment of their potential impact on the fate and transport of antibiotics in the aquatic environment. In this study, adsorption of one common antibiotic, tetracycline, by graphene oxide (GO) and reduced graphene oxide (RGO) was examined with multi-walled carbon nanotubes (MWCNTs) and graphite as comparison. The results showed that the tetracycline adsorption capacity by the four selected carbonaceous materials on the unit mass basis followed an order of GO>RGO>MWCNTs>graphite. Upon normalization by surface area, graphite, RGO and MWCNTs had almost the same high tetracycline adsorption affinity while GO exhibited the lowest. We proposed π-electron-property dependent interaction mechanisms to explain the observed different adsorption behaviors. Density functional theory (DFT) calculations suggested that the oxygen-containing functional groups on GO surface reduced its π-electron-donating ability, and thus decreased the π-based interactions between tetracycline and GO surface. Comparison of adsorption efficiency at different pH indicated that electrostatic interaction also played an important role in tetracycline-GO interactions. Site energy analysis confirmed a highly heterogeneous distribution of the binding sites and strong tetracycline binding affinity of GO surface. Copyright © 2017. Published by Elsevier B.V.

Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

CERN Document Server

Shimizu, S; Furusaka, M

2002-01-01

Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D sub 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D sub 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

A fonoaudiologia na relação entre escolas regulares de ensino fundamental e escolas de educação especial no processo de inclusão Speech therapy in the interaction between regular primary schools and special education schools in the process of inclusion

Directory of Open Access Journals (Sweden)

Alice de Souza Ramos

2008-08-01

Full Text Available A presente pesquisa teve como objetivo conhecer como ocorre o processo de inclusão de crianças com necessidades especiais no Ensino Fundamental, como acontece a comunicação entre escolas de educação especial e regular, bem como a atuação dos inúmeros profissionais envolvidos, enfocando o papel do fonoaudiólogo. Como metodologia, realizou-se um delineamento descritivo e analítico, por meio de inquérito, aplicados em seis Escolas de Educação Especial e seis Escolas de Ensino Regular da Rede Pública Municipal de Belo Horizonte. Participaram do estudo 6 coordenadores e 42 professores de escola regular, nove coordenadores e 61 professores de escola especial, totalizando 118 sujeitos pesquisados. Os questionários abordaram aspectos relacionados à gestão da escola, à formação docente, ao perfil dos alunos, profissionais atuantes no processo educacional, além de formas de contato entre instituições de serviço de Saúde e Educação. Na análise dos resultados, dentre outras questões, foi observada grande demanda para serviço fonoaudiológico, ainda pouco presente na área educacional. A comunicação entre os dois tipos de escola não acontece em todas as instituições pesquisadas. Ambas possuem conhecimento restrito da fonoaudiologia, principalmente as escolas regulares. Percebeu-se a falta de investimento para aperfeiçoamento pessoal dos professores, bem como para orientação aos pais acerca do processo de inclusão. Concluímos que o campo da fonoaudiologia no processo de inclusão mostra-se extenso e aberto. Sua atuação na promoção da saúde em âmbito escolar depende diretamente da interdisciplinaridade entre serviços da área da Educação e da Saúde, além da parceria entre fonoaudiólogos, educadores e pais.This research aimed to investigate the inclusion process of children with special needs in Primary Schools, interaction among regular schools and special education centers, as well as the role of the many

Regularized generalized eigen-decomposition with applications to sparse supervised feature extraction and sparse discriminant analysis

DEFF Research Database (Denmark)

Han, Xixuan; Clemmensen, Line Katrine Harder

2015-01-01

We propose a general technique for obtaining sparse solutions to generalized eigenvalue problems, and call it Regularized Generalized Eigen-Decomposition (RGED). For decades, Fisher's discriminant criterion has been applied in supervised feature extraction and discriminant analysis, and it is for...

Effective field theory dimensional regularization

International Nuclear Information System (INIS)

Lehmann, Dirk; Prezeau, Gary

2002-01-01

A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed

Effective field theory dimensional regularization

Science.gov (United States)

Lehmann, Dirk; Prézeau, Gary

2002-01-01

A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed.

A simple homogeneous model for regular and irregular metallic wire media samples

Science.gov (United States)

Kosulnikov, S. Y.; Mirmoosa, M. S.; Simovski, C. R.

2018-02-01

To simplify the solution of electromagnetic problems with wire media samples, it is reasonable to treat them as the samples of a homogeneous material without spatial dispersion. The account of spatial dispersion implies additional boundary conditions and makes the solution of boundary problems difficult especially if the sample is not an infinitely extended layer. Moreover, for a novel type of wire media - arrays of randomly tilted wires - a spatially dispersive model has not been developed. Here, we introduce a simplistic heuristic model of wire media samples shaped as bricks. Our model covers WM of both regularly and irregularly stretched wires.

Emotion regulation deficits in regular marijuana users.

Science.gov (United States)

Zimmermann, Kaeli; Walz, Christina; Derckx, Raissa T; Kendrick, Keith M; Weber, Bernd; Dore, Bruce; Ochsner, Kevin N; Hurlemann, René; Becker, Benjamin

2017-08-01

Effective regulation of negative affective states has been associated with mental health. Impaired regulation of negative affect represents a risk factor for dysfunctional coping mechanisms such as drug use and thus could contribute to the initiation and development of problematic substance use. This study investigated behavioral and neural indices of emotion regulation in regular marijuana users (n = 23) and demographically matched nonusing controls (n = 20) by means of an fMRI cognitive emotion regulation (reappraisal) paradigm. Relative to nonusing controls, marijuana users demonstrated increased neural activity in a bilateral frontal network comprising precentral, middle cingulate, and supplementary motor regions during reappraisal of negative affect (P marijuana users relative to controls. Together, the present findings could reflect an unsuccessful attempt of compensatory recruitment of additional neural resources in the context of disrupted amygdala-prefrontal interaction during volitional emotion regulation in marijuana users. As such, impaired volitional regulation of negative affect might represent a consequence of, or risk factor for, regular marijuana use. Hum Brain Mapp 38:4270-4279, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Gelation on heating of supercooled gelatin solutions.

Science.gov (United States)

Guigo, Nathanaël; Sbirrazzuoli, Nicolas; Vyazovkin, Sergey

2012-04-23

Diluted (1.0-1.5 wt%) aqueous gelatin solutions have been cooled to -10 °C at a cooling rate 20 °C min(-1) without freezing and detectable gelation. When heated at a constant heating rate (0.5 -2 °C min(-1)), the obtained supercooled solutions demonstrate an atypical process of gelation that has been characterized by regular and stochastically modulated differential scanning calorimetry (DSC) as well as by isoconversional kinetic analysis. The process is detectable as an exothermic peak in the total heat flow of regular DSC and in the nonreversing heat flow of stochastically modulated DSC. Isoconversional kinetic analysis applied to DSC data reveals that the effective activation energy of the process increases from approximately 75 to 200 kJ mol(-1) as a supercooled solution transforms to gel on continuous heating. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantifying the thermodynamic interactions of polyhedral boranes in solution to guide nanocomposite fabrication

Energy Technology Data Exchange (ETDEWEB)

Mutz, M. [University of Tennessee, Department of Chemistry (United States); Eastwood, Eric [Honeywell Kansas City Plant (United States); Lee, Mark E. [University of Missouri (United States); Bowen, Daniel E. [Honeywell Kansas City Plant (United States); Dadmun, M. D., E-mail: dad@utk.edu [University of Tennessee, Department of Chemistry (United States)

2012-11-15

The solubility of boron containing nanoparticles in a variety of solvents is quantified using static light scattering in conjunction with refractometry. Four polyhedral boranes were tested in this work, using refractometry to obtain dn/dc, while static light scattering quantifies A{sub 2}. A{sub 2} obtained from these measurements was then used to calculate {chi}, the solute-solvent interaction parameter, and the Hildebrand solubility parameter, {delta}, which provides a quantifiable method to identify good solvents. Of the nanoparticles studied, 1,3-di-o-carboranylpropane is thermodynamically stable in toluene, with a {chi} less than 0.5, a solubility limit of 2.47 mg/mL, and all solutions remaining clear with no visible particle settling. For all of the particles tested, there was good correlation between the physical observations of the solutions, {chi}, and {delta}. For instance, lower values of {chi} correspond to a smaller radius of gyration (R{sub g}). A list of suitable solvents based on {delta} is also presented.

Regularity criterion for solutions to the Navier Stokes equations in the whole 3D space based on two vorticity components

Czech Academy of Sciences Publication Activity Database

Guo, Z.; Kučera, P.; Skalák, Zdeněk

2018-01-01

Roč. 458, č. 1 (2018), s. 755-766 ISSN 0022-247X R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985874 Keywords : Navier Stokes equations * conditional regularity * regularity criteria * vorticity * Besov spaces * bony decomposition Subject RIV: BA - General Mathematics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.064, year: 2016

Chaos and Integrability in Ideal Body-Fluid Interactions

DEFF Research Database (Denmark)

Pedersen, Johan Rønby

2011-01-01

by generating Poincare sections from numerically obtained solutions. By identifying the chaotic solutions and studying the body and vortex orbits, we obtain a better mechanistic understanding of the causes of chaotic behavior. As is well-known from dynamical system theory, the chaos can often be traced back...... of relative equilibria, their stability, and the qualitatively dierent kinds of motion is studied analytically and numerically. We then perform small parametric perturbations destroying the symmetry or conservation law that makes the system integrable. The emergence of chaos in the system is diagnosed...... contains both regular and chaotic regions, and may be understood from KAM theory. We also discover two separate chaotic regimes in the interaction of a body and one point vortex when the body is either noncircular or has asymmetric internal mass distribution. For one of these chaotic regimes the eect...

Hierarchical regular small-world networks

International Nuclear Information System (INIS)

Boettcher, Stefan; Goncalves, Bruno; Guclu, Hasan

2008-01-01

Two new networks are introduced that resemble small-world properties. These networks are recursively constructed but retain a fixed, regular degree. They possess a unique one-dimensional lattice backbone overlaid by a hierarchical sequence of long-distance links, mixing real-space and small-world features. Both networks, one 3-regular and the other 4-regular, lead to distinct behaviors, as revealed by renormalization group studies. The 3-regular network is planar, has a diameter growing as √N with system size N, and leads to super-diffusion with an exact, anomalous exponent d w = 1.306..., but possesses only a trivial fixed point T c = 0 for the Ising ferromagnet. In turn, the 4-regular network is non-planar, has a diameter growing as ∼2 √(log 2 N 2 ) , exhibits 'ballistic' diffusion (d w = 1), and a non-trivial ferromagnetic transition, T c > 0. It suggests that the 3-regular network is still quite 'geometric', while the 4-regular network qualifies as a true small world with mean-field properties. As an engineering application we discuss synchronization of processors on these networks. (fast track communication)

75 FR 76006 - Regular Meeting

Science.gov (United States)

2010-12-07

... FARM CREDIT SYSTEM INSURANCE CORPORATION Regular Meeting AGENCY: Farm Credit System Insurance Corporation Board. ACTION: Regular meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held...

Interaction of titanium and zirconium hydroxides with aqueous solutions of lead(2) salts

International Nuclear Information System (INIS)

Savenko, V.G.; Sakharov, V.V.; Nurgalieva, A.A.; Petrov, K.I.

1980-01-01

The mixed phases, characterized by the Pb : Zr 4 ratio are synthesized during the process of geterophase interaction of zirconium hydroxide with solutions of lead nitrate and acetate. The process of the mixed phases thermolysis on the base of amorphous zirconium hydroxides is investigated by the methods of DTA, X-ray phase analysis and IR spectroscopy. The metastable phases are formed during the thermolysis process

Fission and fusion interaction phenomena of mixed lump kink solutions for a generalized (3+1)-dimensional B-type Kadomtsev-Petviashvili equation

Science.gov (United States)

Liu, Yaqing; Wen, Xiaoyong

2018-05-01

In this paper, a generalized (3+1)-dimensional B-type Kadomtsev-Petviashvili (gBKP) equation is investigated by using the Hirota’s bilinear method. With the aid of symbolic computation, some new lump, mixed lump kink and periodic lump solutions are derived. Based on the derived solutions, some novel interaction phenomena like the fission and fusion interactions between one lump soliton and one kink soliton, the fission and fusion interactions between one lump soliton and a pair of kink solitons and the interactions between two periodic lump solitons are discussed graphically. Results might be helpful for understanding the propagation of the shallow water wave.

General inverse problems for regular variation

DEFF Research Database (Denmark)

Damek, Ewa; Mikosch, Thomas Valentin; Rosinski, Jan

2014-01-01

Regular variation of distributional tails is known to be preserved by various linear transformations of some random structures. An inverse problem for regular variation aims at understanding whether the regular variation of a transformed random object is caused by regular variation of components ...

Regularized quasinormal modes for plasmonic resonators and open cavities

Science.gov (United States)

Kamandar Dezfouli, Mohsen; Hughes, Stephen

2018-03-01

Optical mode theory and analysis of open cavities and plasmonic particles is an essential component of optical resonator physics, offering considerable insight and efficiency for connecting to classical and quantum optical properties such as the Purcell effect. However, obtaining the dissipative modes in normalized form for arbitrarily shaped open-cavity systems is notoriously difficult, often involving complex spatial integrations, even after performing the necessary full space solutions to Maxwell's equations. The formal solutions are termed quasinormal modes, which are known to diverge in space, and additional techniques are frequently required to obtain more accurate field representations in the far field. In this work, we introduce a finite-difference time-domain technique that can be used to obtain normalized quasinormal modes using a simple dipole-excitation source, and an inverse Green function technique, in real frequency space, without having to perform any spatial integrations. Moreover, we show how these modes are naturally regularized to ensure the correct field decay behavior in the far field, and thus can be used at any position within and outside the resonator. We term these modes "regularized quasinormal modes" and show the reliability and generality of the theory by studying the generalized Purcell factor of dipole emitters near metallic nanoresonators, hybrid devices with metal nanoparticles coupled to dielectric waveguides, as well as coupled cavity-waveguides in photonic crystals slabs. We also directly compare our results with full-dipole simulations of Maxwell's equations without any approximations, and show excellent agreement.

Quantum fields interacting with colliding plane waves: the stress-energy tensor and backreaction

International Nuclear Information System (INIS)

Dorca, M.; Verdaguer, E.

1997-01-01

Following a previous work on the quantization of a massless scalar field in a space-time representing the head on collision of two plane waves which focus into a Killing-Cauchy horizon, we compute the renormalized expectation value of the stress-energy tensor of the quantum field near that horizon in the physical state which corresponds to the Minkowski vacuum before the collision of the waves. It is found that for minimally coupled and conformally coupled scalar fields the respective stress-energy tensors are unbounded in the horizon. The specific form of the divergences suggests that when the semiclassical Einstein equations describing the backreaction of the quantum fields on the space-time geometry are taken into account, the horizon will acquire a curvature singularity. Thus the Killing-Cauchy horizon which is known to be unstable under ''generic'' classical perturbations is also unstable by vacuum polarization. The calculation is done following the point-splitting regularization technique. The dynamical colliding wave space-time has four quite distinct space-time regions, namely, one flat region, two single plane wave regions, and one interaction region. Exact mode solutions of the quantum field equation cannot be found exactly, but the blueshift suffered by the initial modes in the plane wave and interaction regions makes the use of the WKB expansion a suitable method of solution. To ensure the correct regularization of the stress-energy tensor, the initial flat modes propagated into the interaction region must be given to a rather high adiabatic order of approximation. (orig.)

Attractive interactions between reverse aggregates and phase separation in concentrated malonamide extractant solutions

International Nuclear Information System (INIS)

Erlinger, C.; Belloni, L.; Zemb, T.; Madic, C.

1999-01-01

Using small angle X-ray scattering, conductivity, and phase behavior determination, the authors show that concentrated solutions of malonamide extractants, dimethyldibutyltetradecylmalonamide (DMDBTDMA), are organized in reverse oligomeric aggregates which have many features in common with reverse micelles. The aggregation numbers of these reverse globular aggregates as well as their interaction potential are determined from absolute scattering curves. An attractive interaction is responsible for the demixing of the oil phase when in equilibrium with excess oil. Prediction of conductivity as well as the formation conditions for the third phase is possible using standard liquid theory applied to the extractant aggregates. The interactions, modeled with the sticky sphere model proposed by Baster, are shown to be due to steric interactions resulting from the hydrophobic tails of the extractant molecule and van der Waals forces between the highly polarizable water core of the reverse micelles. The attractive interaction in the oil phase, equilibrated with water, is determined as a function of temperature, extractant molecule concentration, and proton and neodynium(III) cation concentration. It is shown that van der Waals interactions, with an effective Hamaker constant of 3kT, quantitatively explain the behavior of DMDBTDMA in n-dodecane in terms of scattering as well as phase stability limits

Geometric theory of fundamental interactions. Foundations of unified physics

International Nuclear Information System (INIS)

Pestov, A.B.

2012-01-01

We put forward an idea that regularities of unified physics are in a simple relation: everything in the concept of space and the concept of space in everything. With this hypothesis as a ground, a conceptual structure of a unified geometrical theory of fundamental interactions is created and deductive derivation of its main equations is produced. The formulated theory gives solution of the actual problems, provides opportunity to understand the origin and nature of physical fields, local internal symmetry, time, energy, spin, charge, confinement, dark energy and dark matter, thus conforming the existence of new physics in its unity

PRIFIRA: General regularization using prior-conditioning for fast radio interferometric imaging†

Science.gov (United States)

Naghibzadeh, Shahrzad; van der Veen, Alle-Jan

2018-06-01

Image formation in radio astronomy is a large-scale inverse problem that is inherently ill-posed. We present a general algorithmic framework based on a Bayesian-inspired regularized maximum likelihood formulation of the radio astronomical imaging problem with a focus on diffuse emission recovery from limited noisy correlation data. The algorithm is dubbed PRIor-conditioned Fast Iterative Radio Astronomy (PRIFIRA) and is based on a direct embodiment of the regularization operator into the system by right preconditioning. The resulting system is then solved using an iterative method based on projections onto Krylov subspaces. We motivate the use of a beamformed image (which includes the classical "dirty image") as an efficient prior-conditioner. Iterative reweighting schemes generalize the algorithmic framework and can account for different regularization operators that encourage sparsity of the solution. The performance of the proposed method is evaluated based on simulated one- and two-dimensional array arrangements as well as actual data from the core stations of the Low Frequency Array radio telescope antenna configuration, and compared to state-of-the-art imaging techniques. We show the generality of the proposed method in terms of regularization schemes while maintaining a competitive reconstruction quality with the current reconstruction techniques. Furthermore, we show that exploiting Krylov subspace methods together with the proper noise-based stopping criteria results in a great improvement in imaging efficiency.

Modeling the growth and interaction of stylolite networks, using the discrete element method for pressure solution

Science.gov (United States)

Makedonska, N.; Sparks, D. W.; Aharonov, E.

2012-12-01

Pressure solution (also termed chemical compaction) is considered the most important ductile deformation mechanism operating in the Earth's upper crust. This mechanism is a major player in a variety of geological processes, including evolution of sedimentary basins, hydrocarbon reservoirs, aquifers, earthquake recurrence cycles, and fault healing. Pressure solution in massive rocks often localizes into solution seams or stylolites. Field observations of stylolites often show elastic/brittle interactions in regions between pressure solution features, including and shear fractures, veins and pull-apart features. To understand these interactions, we use a grain-scale model based on the Discrete Element Method that allows granular dissolution at stressed contacts between grains. The new model captures both the slow chemical compaction process and the more abrupt brittle fracturing and sliding between grains. We simulate a sample of rock as a collection of particles, each representing either a grain or a unit of rock, bonded to each other with breakable cement. We apply external stresses to this sample, and calculate elastic and frictional interactions between the grains. Dissolution is modeled by an irreversible penetration of contacting grains into each other at a rate that depends on the contact stress and an adjustable rate constant. Experiments have shown that dissolution rates at grain contacts are greatly enhanced when there is a mineralogical contrast. Therefore, we dissolution rate constant can be increased to account for an amount of impurities (e.g. clay in a quartz or calcite sandstone) that can accumulate on dissolving contacts. This approach allows large compaction and shear strains within the rock, while allowing examination of local grain-scale heterogeneity. For example, we will describe the effect of pressure solution on the distribution of contact forces magnitudes and orientations. Contact forces in elastic granular packings are inherently

Exact interior solutions in 2 + 1-dimensional spacetime

Energy Technology Data Exchange (ETDEWEB)

Rahaman, Farook; Bhar, Piyali [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Biswas, Ritabrata [Indian Institute of Engineering Sceince and Technology Shibpur, Howrah, West Bengal (India); Usmani, A.A. [Aligarh Muslim University, Department of Physics, Aligarh, Uttar Pradesh (India)

2014-04-15

We provide a new class of exact solutions for the interior in 2 + 1-dimensional spacetime. The solutions obtained for the perfect fluid model both with and without cosmological constant (Λ) are found to be regular and singularity free. It assumes very simple analytical forms that help us to study the various physical properties of the configuration. Solutions without Λ are found to be physically acceptable. (orig.)

Continuum-regularized quantum gravity

International Nuclear Information System (INIS)

Chan Huesum; Halpern, M.B.

1987-01-01

The recent continuum regularization of d-dimensional Euclidean gravity is generalized to arbitrary power-law measure and studied in some detail as a representative example of coordinate-invariant regularization. The weak-coupling expansion of the theory illustrates a generic geometrization of regularized Schwinger-Dyson rules, generalizing previous rules in flat space and flat superspace. The rules are applied in a non-trivial explicit check of Einstein invariance at one loop: the cosmological counterterm is computed and its contribution is included in a verification that the graviton mass is zero. (orig.)

Evasion of No-Hair Theorems and Novel Black-Hole Solutions in Gauss-Bonnet Theories.

Science.gov (United States)

Antoniou, G; Bakopoulos, A; Kanti, P

2018-03-30

We consider a general Einstein-scalar-Gauss-Bonnet theory with a coupling function f(ϕ). We demonstrate that black-hole solutions appear as a generic feature of this theory since a regular horizon and an asymptotically flat solution may be easily constructed under mild assumptions for f(ϕ). We show that the existing no-hair theorems are easily evaded, and a large number of regular black-hole solutions with scalar hair are then presented for a plethora of coupling functions f(ϕ).

Evasion of No-Hair Theorems and Novel Black-Hole Solutions in Gauss-Bonnet Theories

Science.gov (United States)

Antoniou, G.; Bakopoulos, A.; Kanti, P.

2018-03-01

We consider a general Einstein-scalar-Gauss-Bonnet theory with a coupling function f (ϕ ) . We demonstrate that black-hole solutions appear as a generic feature of this theory since a regular horizon and an asymptotically flat solution may be easily constructed under mild assumptions for f (ϕ ). We show that the existing no-hair theorems are easily evaded, and a large number of regular black-hole solutions with scalar hair are then presented for a plethora of coupling functions f (ϕ ).

Interaction Mechanisms between Air Bubble and Molybdenite Surface: Impact of Solution Salinity and Polymer Adsorption.

Science.gov (United States)

Xie, Lei; Wang, Jingyi; Yuan, Duowei; Shi, Chen; Cui, Xin; Zhang, Hao; Liu, Qi; Liu, Qingxia; Zeng, Hongbo

2017-03-07

The surface characteristics of molybdenite (MoS 2 ) such as wettability and surface interactions have attracted much research interest in a wide range of engineering applications, such as froth flotation. In this work, a bubble probe atomic force microscope (AFM) technique was employed to directly measure the interaction forces between an air bubble and molybdenite mineral surface before/after polymer (i.e., guar gum) adsorption treatment. The AFM imaging showed that the polymer coverage on the surface of molybdenite could achieve ∼5.6, ∼44.5, and ∼100% after conditioning in 1, 5, and 10 ppm polymer solution, respectively, which coincided with the polymer coverage results based on contact angle measurements. The electrolyte concentration and surface treatment by polymer adsorption were found to significantly affect bubble-mineral interaction and attachment. The experimental force results on bubble-molybdenite (without polymer treatment) agreed well with the calculations using a theoretical model based on the Reynolds lubrication theory and augmented Young-Laplace equation including the effect of disjoining pressure. The overall surface repulsion was enhanced when the NaCl concentration decreased from 100 to 1 mM, which inhibited the bubble-molybdenite attachment. After conditioning the molybdenite surface in 1 ppm polymer solution, it was more difficult for air bubbles to attach to the molybdenite surface due to the weakened hydrophobic interaction with a shorter decay length. Increasing the polymer concentration to 5 ppm effectively inhibited bubble attachment on mineral surface, which was mainly due to the much reduced hydrophobic interaction as well as the additional steric repulsion between the extended polymer chains and bubble surface. The results provide quantitative information on the interaction mechanism between air bubbles and molybdenite mineral surfaces on the nanoscale, with useful implications for the development of effective polymer

Online co-regularized algorithms

NARCIS (Netherlands)

Ruijter, T. de; Tsivtsivadze, E.; Heskes, T.

2012-01-01

We propose an online co-regularized learning algorithm for classification and regression tasks. We demonstrate that by sequentially co-regularizing prediction functions on unlabeled data points, our algorithm provides improved performance in comparison to supervised methods on several UCI benchmarks

Geometric continuum regularization of quantum field theory

International Nuclear Information System (INIS)

Halpern, M.B.

1989-01-01

An overview of the continuum regularization program is given. The program is traced from its roots in stochastic quantization, with emphasis on the examples of regularized gauge theory, the regularized general nonlinear sigma model and regularized quantum gravity. In its coordinate-invariant form, the regularization is seen as entirely geometric: only the supermetric on field deformations is regularized, and the prescription provides universal nonperturbative invariant continuum regularization across all quantum field theory. 54 refs

Solutions of the Dirac Equation with the Shifted DENG-FAN Potential Including Yukawa-Like Tensor Interaction

Science.gov (United States)

Yahya, W. A.; Falaye, B. J.; Oluwadare, O. J.; Oyewumi, K. J.

2013-08-01

By using the Nikiforov-Uvarov method, we give the approximate analytical solutions of the Dirac equation with the shifted Deng-Fan potential including the Yukawa-like tensor interaction under the spin and pseudospin symmetry conditions. After using an improved approximation scheme, we solved the resulting schr\\"{o}dinger-like equation analytically. Numerical results of the energy eigenvalues are also obtained, as expected, the tensor interaction removes degeneracies between spin and pseudospin doublets.

An entropy regularization method applied to the identification of wave distribution function for an ELF hiss event

Science.gov (United States)

Prot, Olivier; SantolíK, OndřEj; Trotignon, Jean-Gabriel; Deferaudy, Hervé

2006-06-01

An entropy regularization algorithm (ERA) has been developed to compute the wave-energy density from electromagnetic field measurements. It is based on the wave distribution function (WDF) concept. To assess its suitability and efficiency, the algorithm is applied to experimental data that has already been analyzed using other inversion techniques. The FREJA satellite data that is used consists of six spectral matrices corresponding to six time-frequency points of an ELF hiss-event spectrogram. The WDF analysis is performed on these six points and the results are compared with those obtained previously. A statistical stability analysis confirms the stability of the solutions. The WDF computation is fast and without any prespecified parameters. The regularization parameter has been chosen in accordance with the Morozov's discrepancy principle. The Generalized Cross Validation and L-curve criterions are then tentatively used to provide a fully data-driven method. However, these criterions fail to determine a suitable value of the regularization parameter. Although the entropy regularization leads to solutions that agree fairly well with those already published, some differences are observed, and these are discussed in detail. The main advantage of the ERA is to return the WDF that exhibits the largest entropy and to avoid the use of a priori models, which sometimes seem to be more accurate but without any justification.

Substructural Regularization With Data-Sensitive Granularity for Sequence Transfer Learning.

Science.gov (United States)

Sun, Shichang; Liu, Hongbo; Meng, Jiana; Chen, C L Philip; Yang, Yu

2018-06-01

Sequence transfer learning is of interest in both academia and industry with the emergence of numerous new text domains from Twitter and other social media tools. In this paper, we put forward the data-sensitive granularity for transfer learning, and then, a novel substructural regularization transfer learning model (STLM) is proposed to preserve target domain features at substructural granularity in the light of the condition of labeled data set size. Our model is underpinned by hidden Markov model and regularization theory, where the substructural representation can be integrated as a penalty after measuring the dissimilarity of substructures between target domain and STLM with relative entropy. STLM can achieve the competing goals of preserving the target domain substructure and utilizing the observations from both the target and source domains simultaneously. The estimation of STLM is very efficient since an analytical solution can be derived as a necessary and sufficient condition. The relative usability of substructures to act as regularization parameters and the time complexity of STLM are also analyzed and discussed. Comprehensive experiments of part-of-speech tagging with both Brown and Twitter corpora fully justify that our model can make improvements on all the combinations of source and target domains.

Influence of microemulsion-mucin interaction on the fate of microemulsions diffusing through pig gastric mucin solutions.

Science.gov (United States)

Zhang, Jianbin; Lv, Yan; Wang, Bing; Zhao, Shan; Tan, Mingqian; Lv, Guojun; Ma, Xiaojun

2015-03-02

Mucus layer, a selective diffusion barrier, has an important effect on the fate of drug delivery systems in the gastrointestinal tract. To study the fate of microemulsions in the mucus layer, four microemulsion formulations with different particle sizes and lipid compositions were prepared. The microemulsion-mucin interaction was demonstrated by the fluorescence resonance energy transfer (FRET) method. Moreover, the microemulsions were observed aggregated into micron-sized emulsions by laser confocal microscopy. We concluded the microemulsion-mucin interaction not only led to microemulsions closely adhered to mucins but also destroyed the structure of microemulsions. At last, the diffusion of blank microemulsions and microemulsion-carried drugs (resveratrol and hymecromone) through mucin solutions was determined by the fluorescence recovery after photobleaching (FRAP) method and the Franz diffusion cell method. The results demonstrated the diffusion of microemulsions was significantly hindered by mucin solutions. The particle size of microemulsions had a negligible effect on the diffusion coefficients. However, the type of lipid played an important role, which could form hydrophobic interactions with mucins. Interestingly, microemulsion-carried drugs with different core/shell locations seemed to suffer different fates in the mucin solutions. The drug incorporated in the oil core of microemulsions, resveratrol, was transported through the mucus layer by the carriers, while the drug incorporated in the surfactant shell of microemulsions, hymecromone, was separated from the carriers and diffused toward the epithelium in the form of free molecules.

Regularized maximum correntropy machine

KAUST Repository

Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

2015-01-01

In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

Regularized maximum correntropy machine

KAUST Repository

Wang, Jim Jing-Yan

2015-02-12

In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

Results and preliminary analysis of critical experiments with interacting slab solution tanks

International Nuclear Information System (INIS)

Gurin, Victor N.; Ryazanov, Boris G.; Sviridov, Victor I.

2003-01-01

The paper presents the main results of several sets of critical experiments with two interacting similar slab tanks filled with aqueous solution of uranyl nitrate with uranium of 90% enrichment. These experiments were carried out at the RF-GS facility, Obninsk, Russia. Tanks with the thickness of 15 cm, width of 100 cm and height of 120 cm were used in these experiments. The experiments were conducted with partitions made of concrete, brick, polyethylene, cadmium, borated polyethylene. Consideration was given to the dependence of critical volume in each tank on the distance between the tanks and on the partition thickness. The tanks were filled with solutions of highly enriched uranium with its concentrations of 75 g/L and 250 g/L. Critical experiments were analysed with the MCNP 4A code based on the Monte-Carlo method and with the ENDF/B-V library. (author)

A constrained regularization method for inverting data represented by linear algebraic or integral equations

Science.gov (United States)

Provencher, Stephen W.

1982-09-01

CONTIN is a portable Fortran IV package for inverting noisy linear operator equations. These problems occur in the analysis of data from a wide variety experiments. They are generally ill-posed problems, which means that errors in an unregularized inversion are unbounded. Instead, CONTIN seeks the optimal solution by incorporating parsimony and any statistical prior knowledge into the regularizor and absolute prior knowledge into equallity and inequality constraints. This can be greatly increase the resolution and accuracyh of the solution. CONTIN is very flexible, consisting of a core of about 50 subprograms plus 13 small "USER" subprograms, which the user can easily modify to specify special-purpose constraints, regularizors, operator equations, simulations, statistical weighting, etc. Specjial collections of USER subprograms are available for photon correlation spectroscopy, multicomponent spectra, and Fourier-Bessel, Fourier and Laplace transforms. Numerically stable algorithms are used throughout CONTIN. A fairly precise definition of information content in terms of degrees of freedom is given. The regularization parameter can be automatically chosen on the basis of an F-test and confidence region. The interpretation of the latter and of error estimates based on the covariance matrix of the constrained regularized solution are discussed. The strategies, methods and options in CONTIN are outlined. The program itself is described in the following paper.

Solutions of differential equations with regular coefficients by the methods of Richmond and Runge-Kutta

Science.gov (United States)

Cockrell, C. R.

1989-01-01

Numerical solutions of the differential equation which describe the electric field within an inhomogeneous layer of permittivity, upon which a perpendicularly-polarized plane wave is incident, are considered. Richmond's method and the Runge-Kutta method are compared for linear and exponential profiles of permittivities. These two approximate solutions are also compared with the exact solutions.

On convergence rates for iteratively regularized procedures with linear penalty terms

International Nuclear Information System (INIS)

Smirnova, Alexandra

2012-01-01

The impact of this paper is twofold. First, we study convergence rates of the iteratively regularized Gauss–Newton (IRGN) algorithm with a linear penalty term under a generalized source assumption and show how the regularizing properties of new iterations depend on the solution smoothness. Secondly, we introduce an adaptive IRGN procedure, which is investigated under a relaxed smoothness condition. The introduction and analysis of a more general penalty term are of great importance since, apart from bringing stability to the numerical scheme designed for solving a large class of applied inverse problems, it allows us to incorporate various types of a priori information available on the model. Both a priori and a posteriori stopping rules are investigated. For the a priori stopping rule, optimal convergence rates are derived. A numerical example illustrating convergence rates is considered. (paper)

Rational Solutions and Lump Solutions of the Potential YTSF Equation

Science.gov (United States)

Sun, Hong-Qian; Chen, Ai-Hua

2017-07-01

By using of the bilinear form, rational solutions and lump solutions of the potential Yu-Toda-Sasa-Fukuyama (YTSF) equation are derived. Dynamics of the fundamental lump solution, n1-order lump solutions, and N-lump solutions are studied for some special cases. We also find some interaction behaviours of solitary waves and one lump of rational solutions.

Soil solution dynamics of Cu and Zn in a Cu- and Zn-polluted soil as influenced by gamma-irradiation and Cu-Zn interaction.

Science.gov (United States)

Luo, Y M; Yan, W D; Christie, P

2001-01-01

A pot experiment was conducted to study soil solution dynamics of Cu and Zn in a Cu/Zn-polluted soil as influenced by gamma-irradiation and Cu-Zn interaction. A slightly acid sandy loam was amended with Cu and Zn (as nitrates) either singly or in combination (100 mg Cu and 150 mg Zn kg(-1) soil) and was then gamma-irradiated (10 kGy). Unamended and unirradiated controls were included, and spring barley (Hordeum vulgare L. cv. Forrester) was grown for 50 days. Soil solution samples obtained using soil moisture samplers immediately before transplantation and every ten days thereafter were used directly for determination of Cu, Zn, pH and absorbance at 360 nm (A360). Cu and Zn concentrations in the solution of metal-polluted soil changed with time and were affected by gamma-irradiation and metal interaction. gamma-Irradiation raised soil solution Cu substantially but generally decreased soil solution Zn. These trends were consistent with increased dissolved organic matter (A360) and solution pH after gamma-irradiation. Combined addition of Cu and Zn usually gave higher soil solution concentrations of Cu or Zn compared with single addition of Cu or Zn in gamma-irradiated and non-irradiated soils, indicating an interaction between Cu and Zn. Cu would have been organically complexed and consequently maintained a relatively high concentration in the soil solution under higher pH conditions. Zn tends to occur mainly as free ion forms in the soil solution and is therefore sensitive to changes in pH. The extent to which gamma-irradiation and metal interaction affected solubility and bioavailability of Cu and Zn was a function of time during plant growth. Studies on soil solution metal dynamics provide very useful information for understanding metal mobility and bioavailability.

Hip-hop solutions of the 2N-body problem

Science.gov (United States)

Barrabés, Esther; Cors, Josep Maria; Pinyol, Conxita; Soler, Jaume

2006-05-01

Hip-hop solutions of the 2N-body problem with equal masses are shown to exist using an analytic continuation argument. These solutions are close to planar regular 2N-gon relative equilibria with small vertical oscillations. For fixed N, an infinity of these solutions are three-dimensional choreographies, with all the bodies moving along the same closed curve in the inertial frame.

Graded effects of regularity in language revealed by N400 indices of morphological priming.

Science.gov (United States)

Kielar, Aneta; Joanisse, Marc F

2010-07-01

Differential electrophysiological effects for regular and irregular linguistic forms have been used to support the theory that grammatical rules are encoded using a dedicated cognitive mechanism. The alternative hypothesis is that language systematicities are encoded probabilistically in a way that does not categorically distinguish rule-like and irregular forms. In the present study, this matter was investigated more closely by focusing specifically on whether the regular-irregular distinction in English past tenses is categorical or graded. We compared the ERP priming effects of regulars (baked-bake), vowel-change irregulars (sang-sing), and "suffixed" irregulars that display a partial regularity (suffixed irregular verbs, e.g., slept-sleep), as well as forms that are related strictly along formal or semantic dimensions. Participants performed a visual lexical decision task with either visual (Experiment 1) or auditory prime (Experiment 2). Stronger N400 priming effects were observed for regular than vowel-change irregular verbs, whereas suffixed irregulars tended to group with regular verbs. Subsequent analyses decomposed early versus late-going N400 priming, and suggested that differences among forms can be attributed to the orthographic similarity of prime and target. Effects of morphological relatedness were observed in the later-going time period, however, we failed to observe true regular-irregular dissociations in either experiment. The results indicate that morphological effects emerge from the interaction of orthographic, phonological, and semantic overlap between words.

Gravitational Quasinormal Modes of Regular Phantom Black Hole

Directory of Open Access Journals (Sweden)

Jin Li

2017-01-01

Full Text Available We investigate the gravitational quasinormal modes (QNMs for a type of regular black hole (BH known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS, and anti-de Sitter (AdS. In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS, and AdS spacetimes the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameter b, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced by b. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

The interaction of Np(V), Pu(VI) and Tc(VII) with metal in alkaline solutions

International Nuclear Information System (INIS)

Silin, V.I.; Kareta, A.V.

1998-01-01

The interaction of Np(V), Pu(VI) and Tc(VII) with metal reductants Zn, Cr, Sn and their alloys was investigated in 0.5-4 mol l -1 NaOH solutions in static and dynamic conditions (by filtration of solutions through the column filled with grains of metal). In this paper, it was found that the reduction and succeeding precipitation hydroxides of these elements, on the surface of metal grains from 0.5 to 4 mol l -1 NaOH solutions, gives a decontamination factor (DF) from 1.1 to 67. The best result was achieved for Pu (DF=67) on Cr grains after 2.5 h contact at 60 C with 0.5 mol l -1 NaOH solution containing Pu(VI). Increasing the NaOH concentration, and the addition of chromate ions and complex-forming agents to alkaline solution results in a decrease of the decontamination factor (DF). A better result for Np sorption from 1 mol l -1 NaOH solutions was achieved after longer contact, than for Pu, with Cr and Zn grains. The maximum DF=8.9 was achieved for Tc on a column with Zn grains after filtration with a 3.5 mol l -1 NaOH solution containing Tc(VII). Washing out of Np and Pu, sorbed on the Cr grain surfaces, was achieved using an acid solution (1 mol l -1 HNO 3 ). The technetium was desorbed from metal surface by 10% H 2 O 2 solution. (orig.)

Backtracking-Based Iterative Regularization Method for Image Compressive Sensing Recovery

Directory of Open Access Journals (Sweden)

Lingjun Liu

2017-01-01

Full Text Available This paper presents a variant of the iterative shrinkage-thresholding (IST algorithm, called backtracking-based adaptive IST (BAIST, for image compressive sensing (CS reconstruction. For increasing iterations, IST usually yields a smoothing of the solution and runs into prematurity. To add back more details, the BAIST method backtracks to the previous noisy image using L2 norm minimization, i.e., minimizing the Euclidean distance between the current solution and the previous ones. Through this modification, the BAIST method achieves superior performance while maintaining the low complexity of IST-type methods. Also, BAIST takes a nonlocal regularization with an adaptive regularizor to automatically detect the sparsity level of an image. Experimental results show that our algorithm outperforms the original IST method and several excellent CS techniques.

Effective interactions in lysozyme aqueous solutions: a small-angle neutron scattering and computer simulation study.

Science.gov (United States)

Abramo, M C; Caccamo, C; Costa, D; Pellicane, G; Ruberto, R; Wanderlingh, U

2012-01-21

We report protein-protein structure factors of aqueous lysozyme solutions at different pH and ionic strengths, as determined by small-angle neutron scattering experiments. The observed upturn of the structure factor at small wavevectors, as the pH increases, marks a crossover between two different regimes, one dominated by repulsive forces, and another one where attractive interactions become prominent, with the ensuing development of enhanced density fluctuations. In order to rationalize such experimental outcome from a microscopic viewpoint, we have carried out extensive simulations of different coarse-grained models. We have first studied a model in which macromolecules are described as soft spheres interacting through an attractive r(-6) potential, plus embedded pH-dependent discrete charges; we show that the uprise undergone by the structure factor is qualitatively predicted. We have then studied a Derjaguin-Landau-Verwey-Overbeek (DLVO) model, in which only central interactions are advocated; we demonstrate that this model leads to a protein-rich/protein-poor coexistence curve that agrees quite well with the experimental counterpart; experimental correlations are instead reproduced only at low pH and ionic strengths. We have finally investigated a third, "mixed" model in which the central attractive term of the DLVO potential is imported within the distributed-charge approach; it turns out that the different balance of interactions, with a much shorter-range attractive contribution, leads in this latter case to an improved agreement with the experimental crossover. We discuss the relationship between experimental correlations, phase coexistence, and features of effective interactions, as well as possible paths toward a quantitative prediction of structural properties of real lysozyme solutions. © 2012 American Institute of Physics

Solution Phase Measurement of Both Weak Sigma and C-H---X- Hydrogen Bonding Interactions in Synthetic Anion Receptors

Energy Technology Data Exchange (ETDEWEB)

Berryman, Mr. Orion B. [University of Oregon; Sather, Mr. Aaron C [University of Oregon; Hay, Benjamin [ORNL; Meisner, Mr. Jeffrey S. [University of Oregon; Johnson, Prof. Darren W. [University of Oregon

2008-01-01

A series of tripodal receptors preorganize electron-deficient aromatic rings to bind halides in organic solvents using weak sigma anion-to-arene interactions or C-H---X- hydrogen bonds. 1H NMR spectroscopy proves to be a powerful technique for quantifying binding in solution, and determining the interaction motifs, even in cases of weak binding.

Regularity and predictability of human mobility in personal space.

Directory of Open Access Journals (Sweden)

Daniel Austin

Full Text Available Fundamental laws governing human mobility have many important applications such as forecasting and controlling epidemics or optimizing transportation systems. These mobility patterns, studied in the context of out of home activity during travel or social interactions with observations recorded from cell phone use or diffusion of money, suggest that in extra-personal space humans follow a high degree of temporal and spatial regularity - most often in the form of time-independent universal scaling laws. Here we show that mobility patterns of older individuals in their home also show a high degree of predictability and regularity, although in a different way than has been reported for out-of-home mobility. Studying a data set of almost 15 million observations from 19 adults spanning up to 5 years of unobtrusive longitudinal home activity monitoring, we find that in-home mobility is not well represented by a universal scaling law, but that significant structure (predictability and regularity is uncovered when explicitly accounting for contextual data in a model of in-home mobility. These results suggest that human mobility in personal space is highly stereotyped, and that monitoring discontinuities in routine room-level mobility patterns may provide an opportunity to predict individual human health and functional status or detect adverse events and trends.

On the solution of the equations for nonlinear interaction of three damped waves

International Nuclear Information System (INIS)

1976-01-01

Three-wave interactions are analyzed in a coherent wave description assuming different linear damping (or growth) of the individual waves. It is demonstrated that when two of the coefficients of dissipation are equal, the set of equations can be reduced to a single equivalent equation, which in the nonlinearly unstable case, where one wave is undamped, asymptotically takes the form of an equation defining the third Painleve transcendent. It is then possible to find an asymptotic expansion near the time of explosion. This solution is of principal interest since it indicates that the solution of the general three-wave system, where the waves undergo different individual dissipations, belongs to a higher class of functions, which reduces to Jacobian elliptic functions only in the case where all waves suffer the same damping [fr

Acceleration of criticality analysis solution convergence by matrix eigenvector for a system with weak neutron interaction

Energy Technology Data Exchange (ETDEWEB)

Nomura, Yasushi; Takada, Tomoyuki; Kuroishi, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kadotani, Hiroyuki [Shizuoka Sangyo Univ., Iwata, Shizuoka (Japan)

2003-03-01

In the case of Monte Carlo calculation to obtain a neutron multiplication factor for a system of weak neutron interaction, there might be some problems concerning convergence of the solution. Concerning this difficulty in the computer code calculations, theoretical derivation was made from the general neutron transport equation and consideration was given for acceleration of solution convergence by using the matrix eigenvector in this report. Accordingly, matrix eigenvector calculation scheme was incorporated together with procedure to make acceleration of convergence into the continuous energy Monte Carlo code MCNP. Furthermore, effectiveness of acceleration of solution convergence by matrix eigenvector was ascertained with the results obtained by applying to the two OECD/NEA criticality analysis benchmark problems. (author)

Spectroscopic studies on the molecular interaction between salicylic acid and riboflavin (B{sub 2}) in micellar solution

Energy Technology Data Exchange (ETDEWEB)

Bhattar, S.L.; Kolekar, G.B. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra (India); Patil, S.R., E-mail: srp_fsl@rediffmail.co [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra (India)

2010-03-15

The interaction between salicylic acid (SA) and riboflavin (RF) was studied by Fluorescence Resonance Energy Transfer (FRET) in micellar solution. The riboflavin strongly quenches the intrinsic fluorescence of SA by radiative energy transfer. The extent of energy transfer in sodium dodecyl sulphate (SDS) micellar solution of different concentration is quantified from the energy transfer efficiency data. It is seen that the energy transfer is more efficient in the micellar solution. The critical energy transfer distance (R{sub 0}) was determined from which the mean distance between SA and RF molecules was calculated. The quenching was found to fit into Stern-Volmer relation. The results on variation of Stern-Volmer constant (K{sub sv}) with quencher concentration obtained at different temperatures suggested the formation of complex between SA and RF. The association constant of complex formation was estimated and found to decrease with temperature. The values of thermodynamic parameters DELTAH, DELTAG and DELTAS at different temperatures were estimated and the results indicated that the molecular interaction between SA and RF is electrostatic in nature.

Investigation on molecular interaction of amino acids in aqueous disodium hydrogen phosphate solutions with reference to volumetric and compressibility measurements

International Nuclear Information System (INIS)

Kumar, Harsh; Singla, Meenu; Jindal, Rajeev

2014-01-01

Highlights: • Densities and speeds of sound of amino acids in aqueous disodium hydrogen phosphate. • Partial molar volumes and compressibility of transfer. • Positive values of transfer volume indicates interactions between ions of amino acids and TSC. • Ion–hydrophilic and hydrophilic–hydrophilic interactions are present. • Pair-wise interactions are dominant in the mixtures. -- Abstract: The interactions of amino acids glycine (Gly), L-alanine (Ala), and L-valine (Val) with disodium hydrogen phosphate (DSHP) as a function of temperature have been investigated by combination of volumetric and acoustic measurements. Densities (ρ) and speeds of sound (u) of amino acids in aqueous solutions of disodium hydrogen phosphate have been measured at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K and atmospheric pressure. The apparent molar volume (V ϕ ), the partial molar volume (V ϕ 0 ) and standard partial molar volumes of transfer (ΔV ϕ 0 ) for amino acids from water to aqueous disodium hydrogen phosphate solutions have been calculated from density data. Partial molar adiabatic compressibility (κ ϕ,s ) and partial molar adiabatic compressibility of transfer (Δκ ϕ,S 0 ) have been calculated from speed of sound data. The pair (V AB , κ AB ) and triplet (V ABB , κ ABB ) interaction coefficient have been calculated from both the properties. The results have been explained based on competing patterns of interactions of co-solvents and the solute

C1,1 regularity for degenerate elliptic obstacle problems

Science.gov (United States)

Daskalopoulos, Panagiota; Feehan, Paul M. N.

2016-03-01

The Heston stochastic volatility process is a degenerate diffusion process where the degeneracy in the diffusion coefficient is proportional to the square root of the distance to the boundary of the half-plane. The generator of this process with killing, called the elliptic Heston operator, is a second-order, degenerate-elliptic partial differential operator, where the degeneracy in the operator symbol is proportional to the distance to the boundary of the half-plane. In mathematical finance, solutions to the obstacle problem for the elliptic Heston operator correspond to value functions for perpetual American-style options on the underlying asset. With the aid of weighted Sobolev spaces and weighted Hölder spaces, we establish the optimal C 1 , 1 regularity (up to the boundary of the half-plane) for solutions to obstacle problems for the elliptic Heston operator when the obstacle functions are sufficiently smooth.

From static to rotating to conformal static solutions: rotating imperfect fluid wormholes with(out) electric or magnetic field

Energy Technology Data Exchange (ETDEWEB)

Azreg-Ainou, Mustapha [Baskent University, Department of Mathematics, Ankara (Turkey)

2014-05-15

We derive a shortcut stationary metric formula for generating imperfect fluid rotating solutions, in Boyer-Lindquist coordinates, from spherically symmetric static ones. We explore the properties of the curvature scalar and stress-energy tensor for all types of rotating regular solutions we can generate without restricting ourselves to specific examples of regular solutions (regular black holes or wormholes). We show through examples how it is generally possible to generate an imperfect fluid regular rotating solution via radial coordinate transformations. We derive rotating wormholes that are modeled as imperfect fluids and discuss their physical properties. These are independent on the way the stress-energy tensor is interpreted. A solution modeling an imperfect fluid rotating loop black hole is briefly discussed. We then specialize to the recently discussed stable exotic dust Ellis wormhole as emerged in a source-free radial electric or magnetic field, and we generate its, conjecturally stable, rotating counterpart. This turns out to be an exotic imperfect fluid wormhole, and we determine the stress-energy tensor of both the imperfect fluid and the electric or magnetic field. (orig.)

From static to rotating to conformal static solutions: rotating imperfect fluid wormholes with(out) electric or magnetic field

International Nuclear Information System (INIS)

Azreg-Ainou, Mustapha

2014-01-01

We derive a shortcut stationary metric formula for generating imperfect fluid rotating solutions, in Boyer-Lindquist coordinates, from spherically symmetric static ones. We explore the properties of the curvature scalar and stress-energy tensor for all types of rotating regular solutions we can generate without restricting ourselves to specific examples of regular solutions (regular black holes or wormholes). We show through examples how it is generally possible to generate an imperfect fluid regular rotating solution via radial coordinate transformations. We derive rotating wormholes that are modeled as imperfect fluids and discuss their physical properties. These are independent on the way the stress-energy tensor is interpreted. A solution modeling an imperfect fluid rotating loop black hole is briefly discussed. We then specialize to the recently discussed stable exotic dust Ellis wormhole as emerged in a source-free radial electric or magnetic field, and we generate its, conjecturally stable, rotating counterpart. This turns out to be an exotic imperfect fluid wormhole, and we determine the stress-energy tensor of both the imperfect fluid and the electric or magnetic field. (orig.)

Integration of lexical and sublexical processing in the spelling of regular words: a multiple single-case study in Italian dysgraphic patients.

Science.gov (United States)

Laiacona, Marcella; Capitani, Erminio; Zonca, Giusy; Scola, Ilaria; Saletta, Paola; Luzzatti, Claudio

2009-01-01

In this study we investigated 12 cases of "mixed dysgraphia", a spelling impairment where regular words are spelt better than either ambiguous words or regular non-words. Two explanations of mixed dysgraphia were formerly offered by Luzzatti et al. (1998): (i) a double functional lesion of the orthographic output lexicon (or damage to its access) and of the acoustic-to-phonological conversion; and (ii) some kind of interaction/summation between lexical and sublexical spelling routes when processing regular words. We first analysed whether a double functional lesion was sufficient to explain the mixed dysgraphia, checking acoustic-to-phonological conversion by means of the repetition of words and non-words: the answer was positive in five cases and uncertain in three. We tested the remaining four cases to see if there was an interaction between lexical and sublexical processing of regular words, quantifying for each patient, on a probabilistic basis, the separate contribution of the residual lexical and sublexical resources. We investigated whether the processing along these routes was simultaneous but independent ("independent cooperation") or if instead there was "interaction", i.e., the simultaneous activity led to an added increase of efficiency over and above the mere combination of separate success probabilities. For one case the processing along the two routes was independent, in the other three cases an interaction resulted. Following the same approach, we found that for the five cases with a double functional lesion, the observed success on regular word spelling was higher than that expected on a probabilistic basis, but the interpretation of this finding was different.

Regularities of Multifractal Measures

Indian Academy of Sciences (India)

First, we prove the decomposition theorem for the regularities of multifractal Hausdorff measure and packing measure in R R d . This decomposition theorem enables us to split a set into regular and irregular parts, so that we can analyze each separately, and recombine them without affecting density properties. Next, we ...

Equilibrium constant and nitrogen activity and the parameters of interaction eN(N), rN(N,Cr), rN(N,Mn) in high nitrogen steels of Fe-Cr-Mn-N type

International Nuclear Information System (INIS)

Svyazhin, A.G.; Siwka, J.; Rashev, T.

1999-01-01

In the paper a description of a thermodynamic of liquid solutions of Fe-Cr-Mn-N type with using a concept of parameters of an interaction has been presented. A temperature relationship of the equilibrium constant K N(Fe) and values of self interaction parameters e N (N) , r N (N,Cr) , r N (N,Mn) and t N (N,Cr,Cr) has been determined for mean values of temperatures of liquid metal equal 1990 K and 2090 K. By application of a theory of regular solutions those values were recalculated for a temperature 1873 K. (orig.)

Exact solution of the discrete (1+1)-dimensional RSOS model in a slit with field and wall interactions

International Nuclear Information System (INIS)

Owczarek, A L; Prellberg, T

2010-01-01

We present the solution of a linear restricted solid-on-solid (RSOS) model confined to a slit. We include a field-like energy, which equivalently weights the area under the interface, and also include independent interaction terms with both walls. This model can also be mapped to a lattice polymer model of Motzkin paths in a slit interacting with both walls including an osmotic pressure. This work generalizes the previous work on the RSOS model in the half-plane which has a solution that was shown recently to exhibit a novel mathematical structure involving basic hypergeometric functions 3 φ 2 . Because of the mathematical relationship between the half-plane and slit this work hence effectively explores the underlying q-orthogonal polynomial structure to that solution. It also generalizes two other recent works: one on Dyck paths weighted with an osmotic pressure in a slit and another concerning Motzkin paths without an osmotic pressure term in a slit.

Discretizing LTI Descriptor (Regular Differential Input Systems with Consistent Initial Conditions

Directory of Open Access Journals (Sweden)

Athanasios D. Karageorgos

2010-01-01

Full Text Available A technique for discretizing efficiently the solution of a Linear descriptor (regular differential input system with consistent initial conditions, and Time-Invariant coefficients (LTI is introduced and fully discussed. Additionally, an upper bound for the error ‖x¯(kT−x¯k‖ that derives from the procedure of discretization is also provided. Practically speaking, we are interested in such kind of systems, since they are inherent in many physical, economical and engineering phenomena.

Adaptive Regularization of Neural Classifiers

DEFF Research Database (Denmark)

Andersen, Lars Nonboe; Larsen, Jan; Hansen, Lars Kai

1997-01-01

We present a regularization scheme which iteratively adapts the regularization parameters by minimizing the validation error. It is suggested to use the adaptive regularization scheme in conjunction with optimal brain damage pruning to optimize the architecture and to avoid overfitting. Furthermo......, we propose an improved neural classification architecture eliminating an inherent redundancy in the widely used SoftMax classification network. Numerical results demonstrate the viability of the method...

Interactions between colloidal silver and photosynthetic pigments located in cyanobacteria fragments and in solution.

Science.gov (United States)

Siejak, Przemysław; Frackowiak, Danuta