WorldWideScience

Sample records for realistic shell-model interaction

  1. Effective interactions and operators in no-core shell model

    OpenAIRE

    Stetcu, I.; Rotureau, J.

    2012-01-01

    Solutions to the nuclear many-body problem rely on effective interactions, and in general effective operators, to take into account effects not included in calculations. These include effects due to the truncation to finite model spaces where a numerical calculation is tractable, as well as physical terms not included in the description in the first place. In the no-core shell model (NCSM) framework, we discuss two approaches to the effective interactions based on (i) unitary transformations ...

  2. Flexible configuration-interaction shell-model many-body solver

    Energy Technology Data Exchange (ETDEWEB)

    2017-10-01

    BIGSTICK Is a flexible configuration-Interaction open-source shell-model code for the many-fermion problem In a shell model (occupation representation) framework. BIGSTICK can generate energy spectra, static and transition one-body densities, and expectation values of scalar operators. Using the built-in Lanczos algorithm one can compute transition probabflity distributions and decompose wave functions into components defined by group theory.

  3. Shell Model Calculations of the D-State Admixture in the Ground-State Wave Functions of Tritium, HELIUM-3, and HELIUM-4 Using Various Realistic Potentials

    Science.gov (United States)

    Chiang, Pi-Chih

    Several different theoretical methods have been developed to investigate the ground-state properties of ^3H, ^3He, and ^4He nuclei. Previously, the properties of these nuclei have been investigated using variational and hyperspherical methods. However, the Faddeev method, which yields essentially exact results has been used for A = 3 and the coupled-cluster method for mass 4. The error inherent in the hyperspherical method is not known, so the development of alternative method may be useful. In this work we have developed a set of effective operators to be used in the shell-model calculations. The m-scheme shell-model method is used in a systematic study of the binding energy and D-state probability obtained for the ground state of ^3H, ^3He, and ^4He nuclei using a variety of realistic nucleon-nucleon potentials. Since the main contribution to the binding energy comes from the ^1S_0 and ^3S_1 -^3D_1 nucleon -nucleon channels, and the main contribution to the D-state probability comes from the ^3S _1-^3D_1 tensor interaction, we will include only these channels in our calculations. Furthermore, this restriction will allow us to compare our results with the Faddeev five -channel calculations in coordinate space for ^3 H and ^3He. For the trinucleon calculations, we find that our results are in substantial agreement with those of Faddeev calculations. The difference between our results and those of Faddeev calculations is found to be between -0.38 MeV and 0.19 MeV for the triton binding energy and between -0.6% and 0.0% for the triton ground-state D-state probability. For the mass 4 calculations, we compare our results with the published results of hyperspherical, variational, and coupled-cluster calculations. The agreement between this work and that of the URBANA group (48) and Goldhammer (51) is excellent for the binding energy calculations. Our systematic study shows the binding energy (without the static Coulomb contribution) of the alpha particle to be between

  4. Quantified Gamow shell model interaction for p s d -shell nuclei

    Science.gov (United States)

    Jaganathen, Y.; Betan, R. M. Id; Michel, N.; Nazarewicz, W.; Płoszajczak, M.

    2017-11-01

    Background: The structure of weakly bound and unbound nuclei close to particle drip lines is one of the major science drivers of nuclear physics. A comprehensive understanding of these systems goes beyond the traditional configuration interaction approach formulated in the Hilbert space of localized states (nuclear shell model) and requires an open quantum system description. The complex-energy Gamow shell model (GSM) provides such a framework as it is capable of describing resonant and nonresonant many-body states on equal footing. Purpose: To make reliable predictions, quality input is needed that allows for the full uncertainty quantification of theoretical results. In this study, we carry out the optimization of an effective GSM (one-body and two-body) interaction in the p s d f -shell-model space. The resulting interaction is expected to describe nuclei with 5 ≤A ≲12 at the p -s d -shell interface. Method: The one-body potential of the 4He core is modeled by a Woods-Saxon + spin-orbit + Coulomb potential, and the finite-range nucleon-nucleon interaction between the valence nucleons consists of central, spin-orbit, tensor, and Coulomb terms. The GSM is used to compute key fit observables. The χ2 optimization is performed using the Gauss-Newton algorithm augmented by the singular value decomposition technique. The resulting covariance matrix enables quantification of statistical errors within the linear regression approach. Results: The optimized one-body potential reproduces nucleon-4He scattering phase shifts up to an excitation energy of 20 MeV. The two-body interaction built on top of the optimized one-body field is adjusted to the bound and unbound ground-state binding energies and selected excited states of the helium, lithium, and beryllium isotopes up to A =9 . A very good agreement with experimental results was obtained for binding energies. First applications of the optimized interaction include predictions for two-nucleon correlation densities

  5. Pairing properties of realistic effective interactions

    Directory of Open Access Journals (Sweden)

    Gargano A.

    2016-01-01

    Full Text Available We investigate the pairing properties of an effective shell-model interaction defined within a model space outside 132Sn and derived by means of perturbation theory from the CD-Bonn free nucleon-nucleon potential. It turns out that the neutron pairing component of the effective interaction is significantly weaker than the proton one, which accounts for the large pairing gap difference observed in the two-valence identical particle nuclei 134Sn and 134Te. The role of the contribution arising from one particle-one hole excitations in determining the pairing force is discussed and its microscopic structure is also analyzed in terms of the multipole decomposition.

  6. Testing refined shell-model interactions in the sd shell: Coulomb excitation of Na26

    CERN Document Server

    Siebeck, B; Blazhev, A; Reiter, P; Altenkirch, R; Bauer, C; Butler, P A; De Witte, H; Elseviers, J; Gaffney, L P; Hess, H; Huyse, M; Kröll, T; Lutter, R; Pakarinen, J; Pietralla, N; Radeck, F; Scheck, M; Schneiders, D; Sotty, C; Van Duppen, P; Vermeulen, M; Voulot, D; Warr, N; Wenander, F

    2015-01-01

    Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus Na26 with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive beam experiment with Na26 (T1/2=1,07s) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with γ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections...

  7. Shell model calculations for exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.A. (Michigan State Univ., East Lansing, MI (USA)); Warburton, E.K. (Brookhaven National Lab., Upton, NY (USA)); Wildenthal, B.H. (New Mexico Univ., Albuquerque, NM (USA). Dept. of Physics and Astronomy)

    1990-02-01

    In this paper we review the progress of the shell-model approach to understanding the properties of light exotic nuclei (A < 40). By shell-model'' we mean the consistent and large-scale application of the classic methods discussed, for example, in the book of de-Shalit and Talmi. Modern calculations incorporate as many of the important configurations as possible and make use of realistic effective interactions for the valence nucleons. Properties such as the nuclear densities depend on the mean-field potential, which is usually separately from the valence interaction. We will discuss results for radii which are based on a standard Hartree-Fock approach with Skyrme-type interactions.

  8. Effective realistic interactions for low momentum Hilbert spaces

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Dennis

    2012-12-13

    Realistic nucleon-nucleon potentials are an essential ingredient of modern microscopic many-body calculations. These potentials can be represented in two different ways: operator representation or matrix element representation. In operator representation the potential is represented by a set of quantum mechanical operators while in matrix element representation it is defined by the matrix elements in a given basis. Many modern potentials are constructed directly in matrix element representation. While the matrix element representation can be calculated from the operator representation, the determination of the operator representation from the matrix elements is more difficult. Some methods to solve the nuclear many-body problem, such as Fermionic Molecular Dynamics (FMD) or the Green's Function Monte Carlo (GFMC) method, however require explicitly the operator representation of the potential, as they do not work in a fixed many-body basis. It is therefore desirable to derive an operator representation also for the interactions given by matrix elements. In this work a method is presented which allows the derivation of an approximate operator representation starting from the momentum space partial wave matrix elements of the interaction. For that purpose an ansatz for the operator representation is chosen. The parameters in the ansatz are determined by a fit to the partial wave matrix elements. Since a perfect reproduction of the matrix elements in general cannot be achieved with a finite number of operators and the quality of the results depends on the choice of the ansatz, the obtained operator representation is tested in nuclear many-body calculations and the results are compared with those from the initial interaction matrix elements. For the calculation of the nucleon-nucleon scattering phase shifts and the deuteron properties a computer code written within this work is used. For larger nuclei the No Core Shell Model (NCSM) and FMD are applied. The

  9. Operator representation for effective realistic interactions

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Dennis; Feldmeier, Hans; Neff, Thomas [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2013-07-01

    We present a method to derive an operator representation from the partial wave matrix elements of effective realistic nucleon-nucleon potentials. This method allows to employ modern effective interactions, which are mostly given in matrix element representation, also in nuclear many-body methods requiring explicitly the operator representation, for example ''Fermionic Molecular Dynamics'' (FMD). We present results for the operator representation of effective interactions obtained from the Argonne V18 potential with the Uenitary Correlation Operator Method'' (UCOM) and the ''Similarity Renormalization Group'' (SRG). Moreover, the operator representation allows a better insight in the nonlocal structure of the potential: While the UCOM transformed potential only shows a quadratic momentum dependence, the momentum dependence of SRG transformed potentials is beyond such a simple polynomial form.

  10. Symmetry Based No Core Shell Model in a Deformed Basis

    Science.gov (United States)

    Kekejian, David; Draayer, Jerry; Launey, Kristina

    2017-01-01

    To address current limitations of shell-model descriptions of large spatial deformation and cluster structures, we adopt a no-core shell model with a deformed harmonic oscillator basis and implement an angular momentum projection in a symmetry-adapted scheme. This approach allows us to reach larger model spaces as a result of computational memory savings for calculations of highly deformed states, such as the Hoyle state in C-12. The method is first tested with schematic interactions, but the ultimate goal is to carry forward calculations with realistic nucleon-nucleon interactions in future work. Supported by the U.S. NSF (OCI-0904874, ACI-1516338) and the U.S. DOE (DE-SC0005248), and benefitted from computing resources provided by Blue Waters and LSU's Center for Computation & Technology.

  11. Symplectic symmetry and the ab initio no-core shell model

    Energy Technology Data Exchange (ETDEWEB)

    Draayer, J.P.; Dytrych, T.; Sviratcheva, K.D.; Bahri, C. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Vary, J.P. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)

    2007-12-15

    The symplectic symmetry of eigenstates for the O{sub gs}{sup +} in {sup 16}O and the O{sub gs}{sup +}s and lowest 2{sup +} and 4{sup +} configurations of {sup 12}C that are well-converged within the framework of the no-core shell model with the JISP16 realistic interaction is examined. These states are found to project at the 85-90% level onto very few symplectic representations including the most deformed configuration, which confirms the importance of a symplectic no-core shell model and reaffirms the relevance of the Elliott SU(3) model upon which the symplectic scheme is built. (Author)

  12. Clustering aspects and the shell model

    OpenAIRE

    Arima, Akito

    2004-01-01

    In this talk I shall discuss the clustering aspect and the shell model. I shall first discuss the $\\alpha$-cluster aspects based on the shell model calculations. Then I shall discuss the spin zero ground state dominance in the presence of random interactions and a new type of cluster structure for fermions in a single-$j$ shell in the presence of only pairing interaction with the largest multiplicity.

  13. Ground state characteristics of the light nuclei with A<=6 on the basis of the translation invariant shell model by using nucleon-nucleon interaction

    CERN Document Server

    Doma, S B

    2002-01-01

    Phenomenological nucleon-nucleon interaction consisting of central, tensor, spin-orbit and quadratic spin-orbit terms, with Gaussian radial dependence, are constructed by varying their parameters in order to obtain the best fit between the calculated and the experimental values of the binding energy, the root mean-square radius, the D-state probability, the magnetic dipole moment and the electric quadrupole moment of deuteron. The ground-state nuclear wave function of deuteron is expanded in terms of the translation-invariant shell model basis functions corresponding to the number of quanta of excitation 0 <= N <=10. Moreover, the binding energy, the root mean-square radius and the magnetic dipole moment of the nuclei sup 3 H, sup 4 He, sup 5 He and sup 6 Li are also calculated by using the new interactions. The wave functions of these nuclei are expanded in terms of the basis functions of the translation-invariant shell model with N = 10 for the first tow nuclei, N = 7 for sup 5 he and N = 6 for sup 6 ...

  14. Symplectic ab initio no-core shell model

    Energy Technology Data Exchange (ETDEWEB)

    Draayer, J. P.; Dytrych, T.; Sviratcheva, K. D.; Bahri, C. [Department of Physics and Astronomy, Lousiana State University, Baton Rouge, 70803 Lousiana (United States); Vary, J. P. [Department of Physics and Astronomy, Iowa State University, Ames, 50011 Iowa (United States)

    2008-12-15

    The present study confirms the significance of the symplectic Sp(3,R) symmetry in nuclear dynamics as unveiled, for the first time, by examinations of realistic nucleon-nucleon interactions as well as of eigenstates calculated in the framework of the ab initio No-Core Shell Model (NCSM). The results reveal that the NCSM wave functions for light nuclei highly overlap (at the {approx} 90% level) with only a few of the most deformed Sp(3,R)-symmetric basis states. This points to the possibility of achieving convergence of higher-lying collective modes and reaching heavier nuclei by expanding the NCSM basis space beyond its current limits through Sp(3,R) basis states. Furthermore the symplectic symmetry is found to be favored by the JISP 16 and CD-Bonn realistic nucleon-nucleon interactions, which points to a more fundamental origin of the symplectic symmetry. (Author)

  15. No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, B R; Vary, J P; Nogga, A; Navratil, P; Ormand, W E

    2004-01-08

    The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.

  16. Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model

    Energy Technology Data Exchange (ETDEWEB)

    Roth, R; Navratil, P

    2007-05-22

    We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a dramatic reduction of the basis dimension. We analyze the validity and efficiency of this truncation scheme using different realistic nucleon-nucleon interactions and compare to conventional no-core shell model calculations for {sup 4}He and {sup 16}O. Then, we present the first converged calculations for the ground state of {sup 40}Ca within no-core model spaces including up to 16{h_bar}{Omega}-excitations using realistic low-momentum interactions. The scheme is universal and can be easily applied to other quantum many-body problems.

  17. Toward more realistic drug–target interaction predictions

    Science.gov (United States)

    Pahikkala, Tapio; Airola, Antti; Pietilä, Sami; Shakyawar, Sushil; Szwajda, Agnieszka; Tang, Jing

    2015-01-01

    A number of supervised machine learning models have recently been introduced for the prediction of drug–target interactions based on chemical structure and genomic sequence information. Although these models could offer improved means for many network pharmacology applications, such as repositioning of drugs for new therapeutic uses, the prediction models are often being constructed and evaluated under overly simplified settings that do not reflect the real-life problem in practical applications. Using quantitative drug–target bioactivity assays for kinase inhibitors, as well as a popular benchmarking data set of binary drug–target interactions for enzyme, ion channel, nuclear receptor and G protein-coupled receptor targets, we illustrate here the effects of four factors that may lead to dramatic differences in the prediction results: (i) problem formulation (standard binary classification or more realistic regression formulation), (ii) evaluation data set (drug and target families in the application use case), (iii) evaluation procedure (simple or nested cross-validation) and (iv) experimental setting (whether training and test sets share common drugs and targets, only drugs or targets or neither). Each of these factors should be taken into consideration to avoid reporting overoptimistic drug–target interaction prediction results. We also suggest guidelines on how to make the supervised drug–target interaction prediction studies more realistic in terms of such model formulations and evaluation setups that better address the inherent complexity of the prediction task in the practical applications, as well as novel benchmarking data sets that capture the continuous nature of the drug–target interactions for kinase inhibitors. PMID:24723570

  18. Toward more realistic drug-target interaction predictions.

    Science.gov (United States)

    Pahikkala, Tapio; Airola, Antti; Pietilä, Sami; Shakyawar, Sushil; Szwajda, Agnieszka; Tang, Jing; Aittokallio, Tero

    2015-03-01

    A number of supervised machine learning models have recently been introduced for the prediction of drug-target interactions based on chemical structure and genomic sequence information. Although these models could offer improved means for many network pharmacology applications, such as repositioning of drugs for new therapeutic uses, the prediction models are often being constructed and evaluated under overly simplified settings that do not reflect the real-life problem in practical applications. Using quantitative drug-target bioactivity assays for kinase inhibitors, as well as a popular benchmarking data set of binary drug-target interactions for enzyme, ion channel, nuclear receptor and G protein-coupled receptor targets, we illustrate here the effects of four factors that may lead to dramatic differences in the prediction results: (i) problem formulation (standard binary classification or more realistic regression formulation), (ii) evaluation data set (drug and target families in the application use case), (iii) evaluation procedure (simple or nested cross-validation) and (iv) experimental setting (whether training and test sets share common drugs and targets, only drugs or targets or neither). Each of these factors should be taken into consideration to avoid reporting overoptimistic drug-target interaction prediction results. We also suggest guidelines on how to make the supervised drug-target interaction prediction studies more realistic in terms of such model formulations and evaluation setups that better address the inherent complexity of the prediction task in the practical applications, as well as novel benchmarking data sets that capture the continuous nature of the drug-target interactions for kinase inhibitors. © The Author 2014. Published by Oxford University Press.

  19. Recent Developments in No-Core Shell-Model Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Navratil, P; Quaglioni, S; Stetcu, I; Barrett, B R

    2009-03-20

    We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this aproach, we start from realistic two-nucleon or two- plus three-nucleon interactions. Many-body calculations are performed using a finite harmonic-oscillator (HO) basis. To facilitate convergence for realistic inter-nucleon interactions that generate strong short-range correlations, we derive effective interactions by unitary transformations that are tailored to the HO basis truncation. For soft realistic interactions this might not be necessary. If that is the case, the NCSM calculations are variational. In either case, the ab initio NCSM preserves translational invariance of the nuclear many-body problem. In this review, we, in particular, highlight results obtained with the chiral two- plus three-nucleon interactions. We discuss efforts to extend the applicability of the NCSM to heavier nuclei and larger model spaces using importance-truncation schemes and/or use of effective interactions with a core. We outline an extension of the ab initio NCSM to the description of nuclear reactions by the resonating group method technique. A future direction of the approach, the ab initio NCSM with continuum, which will provide a complete description of nuclei as open systems with coupling of bound and continuum states is given in the concluding part of the review.

  20. Symplectic symmetry in the nuclear shell model

    NARCIS (Netherlands)

    French, J.B.

    The nature of the general two-particle interaction which is compatible with symplectic symmetry in the jj coupling shell model is investigated. The essential result is that, to within an additive constant and an additive multiple of T2, the interaction should have the form of a sum of scalar

  1. Shell-model study on event rates of lightest supersymmetric particles scattering off 83Kr and 125Te

    OpenAIRE

    Pirinen, Pekka; Srivastava, P. C.; Suhonen, Jouni; Kortelainen, Markus

    2016-01-01

    We investigate the elastic and inelastic scattering of lightest supersymmetric particle (LSP) dark matter off two possible target nuclei, 83Kr and 125Te. For the nuclear-structure calculations, we employ the nuclear shell model using recently generated realistic interactions. We have condensed the nuclear-physics contribution to a set of nuclear-structure factors that are independent of the adopted supersymmetric (SUSY) model. Total event rates are then easily calculated by combin...

  2. Double beta decay nuclear matrix elements in extended shell model spaces

    Science.gov (United States)

    Horoi, Mihai

    2017-09-01

    In a recent publication we concluded that the shell model double beta decay nuclear matrix elements may be affected to certain degrees by the lack of pairing correlations with orbitals outside the typical shell model spaces. Here we report results of calculations for 48Ca that includes 21 spherical orbitals for both protons and neutrons. We are using a realistic Hamiltonian inside the fp model space, thus maintaining a good description of the nuclear structure properties of the nuclei of interest. We are only allowing pairing interactions between the fp orbitals and the remaining 17 orbitals, and up to two particle excitations in and out of the fp model space. This approach could be also extended to the case of 82Se. Support from U.S. NSF Grant PHY-1404442 and DOE Grants DE-SC0008529 and DE-SC0015376 is acknowledged.

  3. Neutron–19C scattering: Towards including realistic interactions

    Directory of Open Access Journals (Sweden)

    A. Deltuva

    2017-09-01

    Full Text Available Low-energy neutron–C19 scattering is studied in the three-body n+n+C18 model using a realistic nn potential and a number of shallow and deep n–C18 potentials, the latter supporting deeply-bound Pauli-forbidden states that are projected out. Exact Faddeev-type three-body scattering equations for transition operators including two- and three-body forces are solved in the momentum-space partial-wave framework. Phase shift, inelasticity parameter, and cross sections are calculated. For the elastic n–C19 scattering in the JΠ=0+ partial wave the signatures of the Efimov physics, i.e., the pole in the effective-range expansion and the elastic cross section minimum, are confirmed for both shallow and deep models, but with clear quantitative differences between them, indicating the importance of a proper treatment of deeply-bound Pauli-forbidden states. In contrast, the inelasticity parameter is mostly correlated with the asymptotic normalization coefficient of the C19 bound state. Finally, in the regime of very weak C19 binding and near-threshold (bound or virtual excited C20 state the standard Efimovian behaviour of the n–C19 scattering length and cross section was confirmed, resolving the discrepancies between earlier studies by other authors (Mazumdar et al., 2006 [20], Yamashita et al., 2007 [23].

  4. Neutron-19C scattering: Towards including realistic interactions

    Science.gov (United States)

    Deltuva, A.

    2017-09-01

    Low-energy neutron-19C scattering is studied in the three-body n + n +18C model using a realistic nn potential and a number of shallow and deep n-18C potentials, the latter supporting deeply-bound Pauli-forbidden states that are projected out. Exact Faddeev-type three-body scattering equations for transition operators including two- and three-body forces are solved in the momentum-space partial-wave framework. Phase shift, inelasticity parameter, and cross sections are calculated. For the elastic n-19C scattering in the JΠ =0+ partial wave the signatures of the Efimov physics, i.e., the pole in the effective-range expansion and the elastic cross section minimum, are confirmed for both shallow and deep models, but with clear quantitative differences between them, indicating the importance of a proper treatment of deeply-bound Pauli-forbidden states. In contrast, the inelasticity parameter is mostly correlated with the asymptotic normalization coefficient of the 19C bound state. Finally, in the regime of very weak 19C binding and near-threshold (bound or virtual) excited 20C state the standard Efimovian behaviour of the n-19C scattering length and cross section was confirmed, resolving the discrepancies between earlier studies by other authors (Mazumdar et al., 2006 [20], Yamashita et al., 2007 [23]).

  5. Quartet correlations in N = Z nuclei induced by realistic two-body interactions

    Energy Technology Data Exchange (ETDEWEB)

    Sambataro, M. [Istituto Nazionale di Fisica Nucleare - Sezione di Catania, Catania (Italy); Sandulescu, N. [National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)

    2017-03-15

    Two variational quartet models previously employed in a treatment of pairing forces are extended to the case of a general two-body interaction. One model approximates the nuclear states as a condensate of identical quartets with angular momentum J = 0 and isospin T = 0 while the other let these quartets to be all different from each other. With these models we investigate the role of alpha-like quartet correlations both in the ground state and in the lowest J = 0, T = 0 excited states of even-even N = Z nuclei in the sd -shell. We show that the ground-state correlations of these nuclei can be described to a good extent in terms of a condensate of alpha-like quartets. This turns out to be especially the case for the nucleus {sup 32}S for which the overlap between this condensate and the shell model wave function is found close to one. In the same nucleus, a similar overlap is found also in the case of the first excited 0{sup +} state. No clear correspondence is observed instead between the second excited states of the quartet models and the shell model eigenstates in all the cases examined. (orig.)

  6. Toward more realistic drug-target interaction predictions

    National Research Council Canada - National Science Library

    Pahikkala, Tapio; Airola, Antti; Pietilä, Sami; Shakyawar, Sushil; Szwajda, Agnieszka; Tang, Jing; Aittokallio, Tero

    2015-01-01

    .... Using quantitative drug-target bioactivity assays for kinase inhibitors, as well as a popular benchmarking data set of binary drug-target interactions for enzyme, ion channel, nuclear receptor and G...

  7. Temporal structures in shell models

    DEFF Research Database (Denmark)

    Okkels, F.

    2001-01-01

    The intermittent dynamics of the turbulent Gledzer, Ohkitani, and Yamada shell-model is completely characterized by a single type of burstlike structure, which moves through the shells like a front. This temporal structure is described by the dynamics of the instantaneous configuration of the shell...

  8. Temporal Structures in Shell Models

    OpenAIRE

    Okkels, Fridolin

    2000-01-01

    The intermittent dynamics of the turbulent GOY shell-model is characterised by a single type of burst-like structure, which moves through the shells like a front. This temporal structure is described by the dynamics of the instantaneous configuration of the shell-amplitudes revealing a approximative chaotic attractor of the dynamics.

  9. Shell model Monte Carlo methods

    Energy Technology Data Exchange (ETDEWEB)

    Koonin, S.E. [California Inst. of Tech., Pasadena, CA (United States). W.K. Kellogg Radiation Lab.; Dean, D.J. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of {gamma}-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs.

  10. The shell model. Towards a unified description of nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Poves, Alfredo [Departamento de Fisica Teorica, Universidad Autonoma Cantoblanco, 28049 - Madrid (Spain); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    In this series of lectures we present the foundations of the spherical shell model that we treat as an approximation to the exact solution of the full secular problem. We introduce the notions of valence space, effective interaction and effective operator. We analyse the structure of the realistic effective interactions, identifying their monopole part with the spherical mean field. The multipole Hamiltonian is shown to have a universal (simple) form that includes pairing (isovector and isoscalar), quadrupole, octupole, deca-pole, and ({sigma}{center_dot}{tau})({sigma}{center_dot}{tau}). We describe the methods of resolution of the secular problem, in particular the Lanczos method. The model is applied to the description of nuclear deformation and its relationship with the deformed mean field theories is studied. We propose a new symmetry, `quasi`-SU3, to understand deformation in the spherical basis. Finally, we discuss the domain of nuclei very far from the valley of {beta} stability, addressing the vanishing of some magic closures that can be explained in terms of intruder states. (author) 53 refs., 20 figs., 3 tabs.

  11. Measurement of conversion electrons with the $^{208}Pb(p,n)^{208}Bi$ reaction and derivation of the shell model proton neutron hole interaction from the properties of $^{208}Bi$

    CERN Document Server

    Maier, K H; Dracoulis, G D; Boutachkov, P; Aprahamian, A; Byrne, A P; Davidson, P M; Lane, G L; Marie-Jeanne, Mélanie; Nieminen, P; Watanabe, H

    2007-01-01

    Conversion electrons from 208Bi have been measured using singles and coincidence techniques with the 208Pb(p,n)208Bi reaction at 9 MeV. The new information on multipolarities and spins complements that available from recent gamma-gamma-coincidence studies with the same reaction [Boutachkov et al., Nucl. Phys. A768, 22 (2006)]. The results on electromagnetic decays taken together with information on spectroscopic factors from earlier single-particle transfer reaction measurements represent an extensive data set on the properties of the one-proton one-neutron-hole states below 3 MeV, a spectrum which is virtually complete. Comparison of the experimental observables, namely, energies, spectroscopic factors, and gamma-branching ratios, with those calculated within the shell model allows extraction of the matrix elements of the shell model residual interaction. More than 100 diagonal and nondiagonal elements can be determined in this way, through a least squares fit to the experimental data. This adjustment of the...

  12. Shell model description of low-lying states in Po and Rn isotopes

    Directory of Open Access Journals (Sweden)

    Higashiyama Koji

    2014-03-01

    Full Text Available Nuclear structure of the Po and Rn isotopes is theoretically studied in terms of the spherical shell model with the monopole- and quadrupole-pairing plus quadrupole-quadrupole effective interaction. The experimental energy levels of low-lying states are well reproduced. The shell model results are examined in detail in a pair-truncated shell model. The analysis reveals the alignment of two protons in the 0h9/2 orbital at spin 8.

  13. Realistic tool-tissue interaction models for surgical simulation and planning

    NARCIS (Netherlands)

    Misra, Sarthak

    2009-01-01

    Surgical simulators present a safe and potentially effective method for surgical training, and can also be used in pre- and intra-operative surgical planning. Realistic modeling of medical interventions involving tool-tissue interactions has been considered to be a key requirement in the development

  14. Localized versus shell-model-like clusters

    Energy Technology Data Exchange (ETDEWEB)

    Cseh, J.; Algora, A. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Pf. 51, 4001 Hungary (Hungary); Darai, J. [Institute of Experimental Physics, University of Debrecen, Debrecen, Bem ter 18/A, 4026 Hungary (Hungary); Yepez M, H. [Universidad Autonoma de la Ciudad de Mexico, Prolongacion San Isidro 151, Col. San Lorenzo Tezonco, 09790 Mexico D. F. (Mexico); Hess, P. O. [Instituto de Ciencias Nucleares, UNAM, Apartado Postal 70-543, 04510 Mexico D. F. (Mexico)]. e-mail: cseh@atomki.hu

    2008-12-15

    In light of the relation of the shell model and the cluster model, the concepts of localized and shell-model-like clusters are discussed. They are interpreted as different phases of clusterization, which may be characterized by quasi-dynamical symmetries, and are connected by a phase-transition. (Author)

  15. Interactive Web-based Floodplain Simulation System for Realistic Experiments of Flooding and Flood Damage

    Science.gov (United States)

    Demir, I.

    2013-12-01

    Recent developments in web technologies make it easy to manage and visualize large data sets with general public. Novel visualization techniques and dynamic user interfaces allow users to create realistic environments, and interact with data to gain insight from simulations and environmental observations. The floodplain simulation system is a web-based 3D interactive flood simulation environment to create real world flooding scenarios. The simulation systems provides a visually striking platform with realistic terrain information, and water simulation. Students can create and modify predefined scenarios, control environmental parameters, and evaluate flood mitigation techniques. The web-based simulation system provides an environment to children and adults learn about the flooding, flood damage, and effects of development and human activity in the floodplain. The system provides various scenarios customized to fit the age and education level of the users. This presentation provides an overview of the web-based flood simulation system, and demonstrates the capabilities of the system for various flooding and land use scenarios.

  16. Connections between the dynamical symmetries in the microscopic shell model

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, A. I., E-mail: anageorg@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Drumev, K. P. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria)

    2016-03-25

    The dynamical symmetries of the microscopic shell model appear as the limiting cases of a symmetry adapted Pairing-Plus-Quadrupole Model /PQM/, with a Hamiltonian containing isoscalar and isovector pairing and quadrupole interactions. We establish a correspondence between each of the three types of pairing bases and Elliott’s SU(3) basis, that describes collective rotation of nuclear systems with quadrupole deformation. It is derived from their complementarity to the same LS coupling chain of the shell model number conserving algebra. The probability distribution of the S U(3) basis states within the pairing eigenstates is also obtained through a numerical diagonalization of the PQM Hamiltonian in each limit. We introduce control parameters, which define the phase diagram of the model and determine the role of each term of the Hamiltonian in the correct reproduction of the experimental data for the considered nuclei.

  17. Projected shell model description for nuclear isomers

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, Popular Republic (China)

    2008-12-15

    The study of nuclear isomer properties is a current research focus. To describe isomers, we present a method based on the Projected Shell Model. Two kinds of isomers, {kappa}-isomers and shape isomers, are discussed. For the {kappa}-isomer treatment, {kappa}-mixing is properly implemented in the model. It is found however that in order to describe the strong {kappa}-violation more efficiently, it may be necessary to further introduce triaxiality into the shell model basis. To treat shape isomers, a scheme is outlined which allows mixing those configurations belonging to different shapes. (Author)

  18. Relativistic extended Thomas-Fermi calculations of finite nuclei with realistic nucleon-nucleon interactions

    Energy Technology Data Exchange (ETDEWEB)

    Centelles, M.; Vinas, X.; Barranco, M. (Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)); Ohtsuka, N.; Faessler, A.; Khoa, D.T.; Muether, H. (Institut fuer Theoretische Physik, Universitaet Tuebingen, Auf der Morgenstelle 14, D-7400 Tuebingen (Germany))

    1993-03-01

    A relativistic energy density functional is constructed to investigate the Dirac effects on different properties of the structure and scattering of finite nuclei. The kinetic energy density has been derived within a relativistic extended Thomas-Fermi model and includes gradient corrections to second order in [h bar]. The effective mass and the volume term of the potential energy density have been obtained from a local density approximation to Dirac-Brueckner calculations of nuclear matter carried out with a realistic nucleon-nucleon interaction. This volume term is supplemented by the Coulomb energy and by conventional phenomenological surface and symmetry terms, and the few free parameters of the functional are suitably adjusted. Attention is then focused on the calculation of fission barriers of rotating nuclei and of the complex optical potential for heavy ion collisions at intermediate energies. It turns out that the effects of the density-dependent Dirac spinor which have been incorporated in this approach allow for a reasonable description of the investigated properties.

  19. Using interactive workshops to prompt knowledge exchange: a realist evaluation of a knowledge to action initiative.

    Science.gov (United States)

    Rushmer, R K; Hunter, D J; Steven, A

    2014-06-01

    Interactive workshops are often the default mechanism for sharing knowledge across professional and sector boundaries; yet we understand little about if, and how, they work. Between 2009 and 2011, the Research to Reality programme in North East England ran eight stand-alone facilitated multi-agency workshops focused on priority public health issues. Local authorities, the health service, and academe collaborated on the programme to share latest evidence and best practice A realist evaluation asked the overarching question 'what worked where, for whom, and under what conditions' regarding the knowledge exchange (KE) mechanisms underpinning any changes. Data were collected from fifty-one interviews, six observations, and analysis of programme documentation. 191 delegates attended (local authority 46%, NHS 24%, academia 22%, third sector 6%, other 2%). The programme theory was that awareness raising and critical discussion would facilitate ownership and evidence uptake. KE activity included: research digests, academic and senior practitioner presentations, and facilitated round-table discussions. Joint action planning was used to prompt informed follow-up action. Participants valued the digests, expert input, opportunities for discussion, networking and 'space to think'. However, within a few months, sustainability was lost. There was no evidence of direct changes to practice. Multiple barriers to research utilization emerged. The findings suggest that in pressured contexts exacerbated by structural reform providing evidence summaries, input from academic and practice experts, conversational spaces and personal action planning are necessary to create enthusiasm on the day, but are insufficient to prompt practice change in the medium term. The findings question makes assumptions about the instrumental, linear use of knowledge and of change focused on individuals as a driver for organizational change. Delegates' views of 'what would work' are shared. Mechanisms that

  20. Effective Field Theory and the Gamow Shell Model

    OpenAIRE

    Rotureau, J.; van Kolck, U.

    2013-01-01

    We combine Halo/Cluster Effective Field Theory (H/CEFT) and the Gamow Shell Model (GSM) to describe the $0^+$ ground state of $\\rm{^6He}$ as a three-body halo system. We use two-body interactions for the neutron-alpha particle and two-neutron pairs obtained from H/CEFT at leading order, with parameters determined from scattering in the p$_{3/2}$ and s$_0$ channels, respectively. The three-body dynamics of the system is solved using the GSM formalism, where the continuum states are incorporate...

  1. Mapping the Two-Component Atomic Fermi Gas to the Nuclear Shell-Model

    DEFF Research Database (Denmark)

    Özen, C.; Zinner, Nikolaj Thomas

    2014-01-01

    of the external potential becomes important. A system of two-species fermionic cold atoms with an attractive zero-range interaction is analogous to a simple model of nucleus in which neutrons and protons interact only through a residual pairing interaction. In this article, we discuss how the problem of a two......-component atomic fermi gas in a tight external trap can be mapped to the nuclear shell model so that readily available many-body techniques in nuclear physics, such as the Shell Model Monte Carlo (SMMC) method, can be directly applied to the study of these systems. We demonstrate an application of the SMMC method...

  2. Radiative capture reaction {sup 7}Be(p,{gamma}){sup 8}B in the continuum shell model

    Energy Technology Data Exchange (ETDEWEB)

    Bennaceur, K.; Ploszajczak, M. [Grand Accelerateur National d`Ions Lourds (GANIL), Caen (France); Nowacki, F. [Grand Accelerateur National d`Ions Lourds (GANIL), Caen (France)]|[Lab. de Physique Theorique Strasbourg, Strasbourg (France); Okolowicz, J. [Grand Accelerateur National d`Ions Lourds (GANIL), Caen (France)]|[Inst. of Nuclear Physics, Krakow (Poland)

    1998-06-01

    We present here the first application of realistic shell model (SM) including coupling between many-particle (quasi-)bound states and the continuum of one-particle scattering states to the calculation of the total capture cross section and the astrophysical factor in the reaction {sup 7}Be(p,{gamma}){sup 8}B. (orig.)

  3. Translational invariant shell model for Λ hypernuclei

    Directory of Open Access Journals (Sweden)

    Jolos R.V.

    2016-01-01

    Full Text Available We extend shell model for Λ hypernuclei suggested by Gal and Millener by including 2ћω excitations in the translation invariant version to estimate yields of different hyperfragments from primary p-shell hypernuclei. We are inspired by the first successful experiment done at MAMI which opens way to study baryon decay of hypernuclei. We use quantum numbers of group SU(4, [f], and SU(3, (λμ, to classify basis wave functions and calculate coefficients of fractional parentage.

  4. Understanding emergent collectivity and clustering in nuclei from a symmetry-based no-core shell-model perspective

    OpenAIRE

    Dreyfuss, A. C.; Launey, K. D.; Dytrych, T.; Draayer, J. P.; Baker, R. B.; Deibel, C. M.; Bahri, C.

    2016-01-01

    We present a detailed discussion of the structure of the low-lying positive-parity energy spectrum of $^{12}$C from a no-core shell-model perspective. The approach utilizes a fraction of the usual shell-model space and extends its multi-shell reach via the symmetry-based no-core symplectic shell model (NCSpM) with a simple, physically-informed effective interaction. We focus on the ground-state rotational band, the Hoyle state and its $2^+$ and $4^+$ excitations, as well as the giant monopole...

  5. Phases and phase transitions in the algebraic microscopic shell model

    Directory of Open Access Journals (Sweden)

    Georgieva A. I.

    2016-01-01

    Full Text Available We explore the dynamical symmetries of the shell model number conserving algebra, which define three types of pairing and quadrupole phases, with the aim to obtain the prevailing phase or phase transition for the real nuclear systems in a single shell. This is achieved by establishing a correspondence between each of the pairing bases with the Elliott’s SU(3 basis that describes collective rotation of nuclear systems. This allows for a complete classification of the basis states of different number of particles in all the limiting cases. The probability distribution of the SU(3 basis states within theirs corresponding pairing states is also obtained. The relative strengths of dynamically symmetric quadrupole-quadrupole interaction in respect to the isoscalar, isovector and total pairing interactions define a control parameter, which estimates the importance of each term of the Hamiltonian in the correct reproduction of the experimental data for the considered nuclei.

  6. Dynamical symmetries of the shell model

    Energy Technology Data Exchange (ETDEWEB)

    Van Isacker, P

    2000-07-01

    The applications of spectrum generating algebras and of dynamical symmetries in the nuclear shell model are many and varied. They stretch back to Wigner's early work on the supermultiplet model and encompass important landmarks in our understanding of the structure of the atomic nucleus such as Racah's SU(2) pairing model and Elliot's SU(3) rotational model. One of the aims of this contribution has been to show the historical importance of the idea of dynamical symmetry in nuclear physics. Another has been to indicate that, in spite of being old, this idea continues to inspire developments that are at the forefront of today's research in nuclear physics. It has been argued in this contribution that the main driving features of nuclear structure can be represented algebraically but at the same time the limitations of the symmetry approach must be recognised. It should be clear that such approach can only account for gross properties and that any detailed description requires more involved numerical calculations of which we have seen many fine examples during this symposium. In this way symmetry techniques can be used as an appropriate starting point for detailed calculations. A noteworthy example of this approach is the pseudo-SU(3) model which starting from its initial symmetry Ansatz has grown into an adequate and powerful description of the nucleus in terms of a truncated shell model. (author)

  7. Gamow shell-model description of weakly bound and unbound nuclear states

    Energy Technology Data Exchange (ETDEWEB)

    Michel, N.; Nazarewicz, W. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Ploszajczak, M.; Rotureau, J. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DSM- NRS/IN2P3, BP 55027, F-14076 Caen Cedex 05 (France)

    2004-12-01

    Recently, the shell model in the complex k-plane (the so-called Gamow Shell Model) has been formulated using a complex Berggren ensemble representing bound single-particle states, single-particle resonances, and non-resonant continuum states. In this framework, we shall discuss binding energies and energy spectra of neutron-rich helium and lithium isotopes. The single-particle basis used is that of the Hartree-Fock potential generated self-consistently by the finite-range residual interaction. (Author) 21 refs., 5 tabs., 2 figs.

  8. Rotational band structure of intruder configurations -- Success and limitations of the cranked shell model

    Energy Technology Data Exchange (ETDEWEB)

    Wyss, R. [Joint Inst. for Heavy-Ion Research, Oak Ridge, TN (United States). Holifield Heavy Ion Research Facility

    1993-12-31

    Rotational bands built on intruder configurations are discussed within the Cranked Shell Model. The experimental observed alignment pattern occurring in these bands cannot be accounted for by standard mean field calculations. The discrepancy between theory and experiment is traced back to the fact that the neutron-proton interaction is only partly and indirectly included in the standard mean field approach.

  9. Shell model for warm rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, M.; Yoshida, K. [Kyoto Univ. (Japan); Dossing, T. [Univ. of Copenhagen (Denmark)] [and others

    1996-12-31

    Utilizing a shell model which combines the cranked Nilsson mean-field and the residual surface and volume delta two-body forces, the authors discuss the onset of rotational damping in normal- and super-deformed nuclei. Calculation for a typical normal deformed nucleus {sup 168}Yb indicates that the rotational damping sets in at around 0.8 MeV above the yrast line, and about 30 rotational bands of various length exists at a given rotational frequency, in overall agreement with experimental findings. It is predicted that the onset of rotational damping changes significantly in different superdeformed nuclei due to the variety of the shell gaps and single-particle orbits associated with the superdeformed mean-field.

  10. Proceedings of a symposium on the occasion of the 40th anniversary of the nuclear shell model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.S.H.; Wiringa, R.B. (eds.)

    1990-03-01

    This report contains papers on the following topics: excitation of 1p-1h stretched states with the (p,n) reaction as a test of shell-model calculations; on Z=64 shell closure and some high spin states of {sup 149}Gd and {sup 159}Ho; saturating interactions in {sup 4}He with density dependence; are short-range correlations visible in very large-basis shell-model calculations ; recent and future applications of the shell model in the continuum; shell model truncation schemes for rotational nuclei; the particle-hole interaction and high-spin states near A-16; magnetic moment of doubly closed shell +1 nucleon nucleus {sup 41}Sc(I{sup {pi}}=7/2{sup {minus}}); the new magic nucleus {sup 96}Zr; comparing several boson mappings with the shell model; high spin band structures in {sup 165}Lu; optical potential with two-nucleon correlations; generalized valley approximation applied to a schematic model of the monopole excitation; pair approximation in the nuclear shell model; and many-particle, many-hole deformed states.

  11. Setting realistic recovery targets for two interacting endangered species, sea otter and northern abalone.

    Science.gov (United States)

    Chadès, Iadine; Curtis, Janelle M R; Martin, Tara G

    2012-12-01

    Failure to account for interactions between endangered species may lead to unexpected population dynamics, inefficient management strategies, waste of scarce resources, and, at worst, increased extinction risk. The importance of species interactions is undisputed, yet recovery targets generally do not account for such interactions. This shortcoming is a consequence of species-centered legislation, but also of uncertainty surrounding the dynamics of species interactions and the complexity of modeling such interactions. The northern sea otter (Enhydra lutris kenyoni) and one of its preferred prey, northern abalone (Haliotis kamtschatkana), are endangered species for which recovery strategies have been developed without consideration of their strong predator-prey interactions. Using simulation-based optimization procedures from artificial intelligence, namely reinforcement learning and stochastic dynamic programming, we combined sea otter and northern abalone population models with functional-response models and examined how different management actions affect population dynamics and the likelihood of achieving recovery targets for each species through time. Recovery targets for these interacting species were difficult to achieve simultaneously in the absence of management. Although sea otters were predicted to recover, achieving abalone recovery targets failed even when threats to abalone such as predation and poaching were reduced. A management strategy entailing a 50% reduction in the poaching of northern abalone was a minimum requirement to reach short-term recovery goals for northern abalone when sea otters were present. Removing sea otters had a marginally positive effect on the abalone population but only when we assumed a functional response with strong predation pressure. Our optimization method could be applied more generally to any interacting threatened or invasive species for which there are multiple conservation objectives. © 2012 Society for

  12. Anticipation- and error-related EEG signals during realistic human-machine interaction: a study on visual and tactile feedback.

    Science.gov (United States)

    Chavarriaga, Ricardo; Perrin, Xavier; Siegwart, Roland; Millán, José del R

    2012-01-01

    The exploitation of EEG signatures of cognitive processes can provide valuable information to improve interaction with brain actuated devices. In this work we study these correlates in a realistic situation simulated in a virtual reality environment. We focus on cortical potentials linked to the anticipation of future events (i.e. the contingent negative variation, CNV) and error-related potentials elicited by both visual and tactile feedback. Experiments with 6 subjects show brain activity consistent with previous studies using simpler stimuli, both at the level of ERPs and single trial classification. Moreover, we observe comparable signals irrespective of whether the subject was required to perform motor actions. Altogether, these results support the possibility of using these signals for practical brain machine interaction.

  13. Hyper-realistic and interactive three-dimensional visualization: Holy Chamber and Jewels of the Cathedral of Oviedo

    Directory of Open Access Journals (Sweden)

    Julio Ruiz

    2015-10-01

    Full Text Available The New developments in 3D data registration and post processing have enabled us to obtain models whose final design means a qualitative step in order to reach a much more realistic viewing of them for both cases: sculptures and architectural monuments. Uniting 3D scanning technologies, photogrammetry, texture mapping, 3D imaging software tools and interactive content, we found novel and higher levels of quality in the images. Thanks to the new software display - with these images made in Unity - a new field emerges which find applications in improved interactivity , cellular phones, tablets, augmented reality and related technologies, as well as in the development of future platforms such as holodisplays, auto stereoscopic 3D television computer vision, etc. In this way it provides an excellent tool for heritage but a valuable working tool for professionals too.

  14. Simulated evolution of protein-protein interaction networks with realistic topology.

    Science.gov (United States)

    Peterson, G Jack; Pressé, Steve; Peterson, Kristin S; Dill, Ken A

    2012-01-01

    We model the evolution of eukaryotic protein-protein interaction (PPI) networks. In our model, PPI networks evolve by two known biological mechanisms: (1) Gene duplication, which is followed by rapid diversification of duplicate interactions. (2) Neofunctionalization, in which a mutation leads to a new interaction with some other protein. Since many interactions are due to simple surface compatibility, we hypothesize there is an increased likelihood of interacting with other proteins in the target protein's neighborhood. We find good agreement of the model on 10 different network properties compared to high-confidence experimental PPI networks in yeast, fruit flies, and humans. Key findings are: (1) PPI networks evolve modular structures, with no need to invoke particular selection pressures. (2) Proteins in cells have on average about 6 degrees of separation, similar to some social networks, such as human-communication and actor networks. (3) Unlike social networks, which have a shrinking diameter (degree of maximum separation) over time, PPI networks are predicted to grow in diameter. (4) The model indicates that evolutionarily old proteins should have higher connectivities and be more centrally embedded in their networks. This suggests a way in which present-day proteomics data could provide insights into biological evolution.

  15. Effectively-truncated large-scale shell-model calculations and nuclei around 100Sn

    Science.gov (United States)

    Gargano, A.; Coraggio, L.; Itaco, N.

    2017-09-01

    This paper presents a short overview of a procedure we have recently introduced, dubbed the double-step truncation method, which is aimed to reduce the computational complexity of large-scale shell-model calculations. Within this procedure, one starts with a realistic shell-model Hamiltonian defined in a large model space, and then, by analyzing the effective single particle energies of this Hamiltonian as a function of the number of valence protons and/or neutrons, reduced model spaces are identified containing only the single-particle orbitals relevant to the description of the spectroscopic properties of a certain class of nuclei. As a final step, new effective shell-model Hamiltonians defined within the reduced model spaces are derived by way of a unitary transformation of the original large-scale Hamiltonian. A detailed account of this transformation is given and the merit of the double-step truncation method is illustrated by discussing few selected results for 96Mo, described as four protons and four neutrons outside 88Sr. Some new preliminary results for light odd-tin isotopes from A = 101 to 107 are also reported.

  16. Unified description of pf-shell nuclei by the Monte Carlo shell model calculations

    Energy Technology Data Exchange (ETDEWEB)

    Mizusaki, Takahiro; Otsuka, Takaharu [Tokyo Univ. (Japan). Dept. of Physics; Honma, Michio

    1998-03-01

    The attempts to solve shell model by new methods are briefed. The shell model calculation by quantum Monte Carlo diagonalization which was proposed by the authors is a more practical method, and it became to be known that it can solve the problem with sufficiently good accuracy. As to the treatment of angular momentum, in the method of the authors, deformed Slater determinant is used as the basis, therefore, for making angular momentum into the peculiar state, projected operator is used. The space determined dynamically is treated mainly stochastically, and the energy of the multibody by the basis formed as the result is evaluated and selectively adopted. The symmetry is discussed, and the method of decomposing shell model space into dynamically determined space and the product of spin and isospin spaces was devised. The calculation processes are shown with the example of {sup 50}Mn nuclei. The calculation of the level structure of {sup 48}Cr with known exact energy can be done with the accuracy of peculiar absolute energy value within 200 keV. {sup 56}Ni nuclei are the self-conjugate nuclei of Z=N=28. The results of the shell model calculation of {sup 56}Ni nucleus structure by using the interactions of nuclear models are reported. (K.I.)

  17. Realistic Modeling of Interaction of Quiet-Sun Magnetic Fields with the Chromosphere

    Science.gov (United States)

    Kitiashvili, I. N.; Kosovichev, A. G.; Mansour, N. N.; Wray, A. A.

    2017-01-01

    High­-resolution observations and 3D MHD simulations reveal intense interaction between the convection zone dynamics and the solar atmosphere on subarcsecond scales. To investigate processes of the dynamical coupling and energy exchange between the subsurface layers and the chromosphere we perform 3D radiative MHD modeling for a computational domain that includes the upper convection zone and the chromosphere, and investigate the structure and dynamics for different intensity of the photospheric magnetic flux. For comparison with observations, the simulation models have been used to calculate synthetic Stokes profiles of various spectral lines. The results show intense energy exchange through small­-scale magnetized vortex tubes rooted below the photosphere, which provide extra heating of the chromosphere, initiate shock waves, and small­-scale eruptions.

  18. Smelling is Telling: Human Olfactory Cues Influence Social Judgments in Semi-Realistic Interactions.

    Science.gov (United States)

    Gaby, Jessica M; Zayas, Vivian

    2017-06-01

    How does a person's smell affect others' impressions of them? Most body odor research asks perceivers to make social judgments based on armpit sweat without perfume or deodorant, presented on t-shirts. Yet, in real life, perceivers encounter fragranced body odor, on whole bodies. Our "raters" wore blindfolds and earplugs and repeatedly smelled same-sex "donors" in live interactions. In one condition, donors wore their normal deodorant and perfume ("diplomatic" odor) while in the other condition, donors were asked to avoid all outside fragrance influences ("natural" odor). We assessed the reliability of social judgments based on such live interactions, and the relationships between live judgments and traditional t-shirt based judgments, and between natural- and diplomatic odor-based judgments. Raters' repeated live social judgments (e.g., friendliness, likeability) were highly consistent for both diplomatic and natural odor, and converged with judgments based on t-shirts. However, social judgments based on natural odor did not consistently predict social judgments based on diplomatic odor, suggesting that natural and diplomatic body odor may convey different types of social information. Our results provide evidence that individuals can perceive reliable, meaningful social olfactory signals from whole bodies, at social distances, regardless of the presence or absence of perfume. Importantly, however, the social value of these signals is modified by the addition of exogenous fragrances. Further, our focus on judgments in same-sex dyads suggests that these olfactory cues hold social value in non-mating contexts. We suggest that future research employ more ecologically relevant methods. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Shell-model representation to describe α emission

    Science.gov (United States)

    Delion, D. S.; Liotta, R. J.

    2013-04-01

    It is shown that the standard shell-model representation is inadequate to explain cluster decay processes due to a deficient asymptotic behavior of the corresponding single-particle wave functions. A new representation is proposed which is derived from a mean field consisting of the standard Woods-Saxon plus spin-orbit potential of the shell model, with an additional attractive pocket potential of a Gaussian form localized on the nuclear surface. The eigenvectors of this new mean field provide a representation which retains all the benefits of the standard shell model while at the same time reproducing well the experimental absolute α-decay widths from heavy nuclei.

  20. Multi-Shell Shell Model for Heavy Nuclei

    OpenAIRE

    Sun, Yang; Wu, Cheng-Li

    2003-01-01

    Performing a shell model calculation for heavy nuclei has been a long-standing problem in nuclear physics. Here we propose one possible solution. The central idea of this proposal is to take the advantages of two existing models, the Projected Shell Model (PSM) and the Fermion Dynamical Symmetry Model (FDSM), to construct a multi-shell shell model. The PSM is an efficient method of coupling quasi-particle excitations to the high-spin rotational motion, whereas the FDSM contains a successful t...

  1. Travel for the 2004 American Statistical Association Biannual Radiation Meeting: "Radiation in Realistic Environments: Interactions Between Radiation and Other Factors

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-21

    The 16th ASA Conference on Radiation and Health, held June 27-30, 2004 in Beaver Creek, CO, offered a unique forum for discussing research related to the effects of radiation exposures on human health in a multidisciplinary setting. The Conference furnishes investigators in health related disciplines the opportunity to learn about new quantitative approaches to their problems and furnishes statisticians the opportunity to learn about new applications for their discipline. The Conference was attended by about 60 scientists including statisticians, epidemiologists, biologists and physicists interested in radiation research. For the first time, ten recipients of Young Investigator Awards participated in the conference. The Conference began with a debate on the question: “Do radiation doses below 1 cGy increase cancer risks?” The keynote speaker was Dr. Martin Lavin, who gave a banquet presentation on the timely topic “How important is ATM?” The focus of the 2004 Conference on Radiation and Health was Radiation in Realistic Environments: Interactions Between Radiation and Other Risk Modifiers. The sessions of the conference included: Radiation, Smoking, and Lung Cancer Interactions of Radiation with Genetic Factors: ATM Radiation, Genetics, and Epigenetics Radiotherapeutic Interactions The Conference on Radiation and Health is held bi-annually, and participants are looking forward to the 17th conference to be held in 2006.

  2. CrashEd – A live immersive, learning experience embedding STEM subjects in a realistic, interactive crime scene

    Directory of Open Access Journals (Sweden)

    Marie L. Bassford

    2016-09-01

    Full Text Available Interactive experiences are rapidly becoming popular via the surge of ‘escape rooms’; part game and part theatre, the ‘escape’ experience is exploding globally, having gone from zero offered at the outset of 2010 to at least 2800 different experiences available worldwide today. CrashEd is an interactive learning experience that parallels many of the attractions of an escape room – it incorporates a staged, realistic ‘crime scene’ and invites participants to work together to gather forensic evidence and question a witness in order to solve a crime, all whilst competing against a ticking clock. An animation can enhance reality and engage with cognitive processes to help learning; in CrashEd, it is the last piece of the jigsaw that consolidates the students’ incremental acquisition of knowledge to tie together the pieces of evidence, identify a suspect and ultimately solve the crime. This article presents the background to CrashEd and an overview of how a timely placed animation at the end of an educational experience can enhance learning. The lessons learned, from delivering bespoke versions of the experience to different demographic groups, are discussed. The article will consider the successes and challenges raised by the collaborative project, future developments and potential wider implications of the development of CrashEd.

  3. Shell model results for T = 1 and T = 0 bands in 66As

    Science.gov (United States)

    Srivastava, Praveen C.; Sahu, R.; Kota, V. K. B.

    2017-12-01

    The results of comprehensive shell model (SM) analyses, within the full {f}5/2{{pg}}9/2 model space, of the recently available experimental data (Ruotsalainen et al (2013) Phys. Rec. C 88 024320) with four T = 0 bands and one T = 1 band in the odd–odd N = Z nucleus 66As are presented. The calculations are performed by using the jj44b effective interaction developed recently by Brown and Lisetskiy for this model space. For the lowest two T = 0 bands and the T = 1 band, the results are in reasonable agreement with experimental data and the deformed shell model is used to identify their intrinsic structure. For the T = 1 band, a structural change at {8}+ is predicted. For the third {9}+ band with T = 0, the shell model B(E2) values and quadrupole moments (in addition to energies) are consistent with the interpretation in terms of an aligned isoscalar np pair in a {g}9/2 orbit coupled to the 64Ge ground band. Similarly, the {9}+ level of band 4 and a close-lying {5}+ level are found to be isomeric states in the analysis. Finally, the energies of the band 5 members, calculated using the shell model with both positive and negative parity, show that the observed levels are most likely negative parity levels. The shell model results with jj44b are compared with results obtained using the JUN45 interaction.

  4. Cascades and statistical equilibrium in shell models of turbulence

    CERN Document Server

    Ditlevsen, P D

    1996-01-01

    We study the GOY shell model simulating the cascade processes of turbulent flow. The model has two inviscid invariants governing the dynamical behavior. Depending on the choice of interaction coefficients, or coupling parameters, the two invariants are either both positive definite, analogous to energy and enstrophy of 2D flow, or only one is positive definite and the other not, analogous to energy and helicity of 3D flow. In the 2D like model the dynamics depend on the spectral ratio of enstrophy to energy. That ratio depends on wave-number as $k^{\\alpha}$. The enstrophy transfer through the inertial sub-range can be described as a forward cascade for $\\alpha 2$. The $\\alpha =2$ case, corresponding to 2D turbulence, is a borderline between the two descriptions. The difference can be understood in terms of the ratio of typical timescales in the inertial sub-range and in the viscous sub-range. The multi fractality of the enstrophy dissipation also depends on the parameter $\\alpha$, and seems to be related to ...

  5. A Shell Model for Free Vibration Analysis of Carbon Nanoscroll

    Directory of Open Access Journals (Sweden)

    Amin Taraghi Osguei

    2017-04-01

    Full Text Available Carbon nanoscroll (CNS is a graphene sheet rolled into a spiral structure with great potential for different applications in nanotechnology. In this paper, an equivalent open shell model is presented to study the vibration behavior of a CNS with arbitrary boundary conditions. The equivalent parameters used for modeling the carbon nanotubes are implemented to simulate the CNS. The interactions between the layers of CNS due to van der Waals forces are included in the model. The uniformly distributed translational and torsional springs along the boundaries are considered to achieve a unified solution for different boundary conditions. To study the vibration characteristics of CNS, total energy including strain energy, kinetic energy, and van der Waals energy are minimized using the Rayleigh-Ritz technique. The first-order shear deformation theory has been utilized to model the shell. Chebyshev polynomials of first kind are used to obtain the eigenvalue matrices. The natural frequencies and corresponding mode shapes of CNS in different boundary conditions are evaluated. The effect of electric field in axial direction on the natural frequencies and mode shapes of CNS is investigated. The results indicate that, as the electric field increases, the natural frequencies decrease.

  6. Van der Waals coefficients beyond the classical shell model

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Jianmin, E-mail: jianmint@sas.upenn.edu [Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 (United States); Fang, Yuan; Hao, Pan [Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118 (United States); Scuseria, G. E. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892, USA and Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Ruzsinszky, Adrienn; Perdew, John P. [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)

    2015-01-14

    Van der Waals (vdW) coefficients can be accurately generated and understood by modelling the dynamic multipole polarizability of each interacting object. Accurate static polarizabilities are the key to accurate dynamic polarizabilities and vdW coefficients. In this work, we present and study in detail a hollow-sphere model for the dynamic multipole polarizability proposed recently by two of the present authors (JT and JPP) to simulate the vdW coefficients for inhomogeneous systems that allow for a cavity. The inputs to this model are the accurate static multipole polarizabilities and the electron density. A simplification of the full hollow-sphere model, the single-frequency approximation (SFA), circumvents the need for a detailed electron density and for a double numerical integration over space. We find that the hollow-sphere model in SFA is not only accurate for nanoclusters and cage molecules (e.g., fullerenes) but also yields vdW coefficients among atoms, fullerenes, and small clusters in good agreement with expensive time-dependent density functional calculations. However, the classical shell model (CSM), which inputs the static dipole polarizabilities and estimates the static higher-order multipole polarizabilities therefrom, is accurate for the higher-order vdW coefficients only when the interacting objects are large. For the lowest-order vdW coefficient C{sub 6}, SFA and CSM are exactly the same. The higher-order (C{sub 8} and C{sub 10}) terms of the vdW expansion can be almost as important as the C{sub 6} term in molecular crystals. Application to a variety of clusters shows that there is strong non-additivity of the long-range vdW interactions between nanoclusters.

  7. Shell-model description of weakly bound and unbound nuclear states

    Energy Technology Data Exchange (ETDEWEB)

    Michel, N. [University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Oak Ridge National Laboratory, Physics Division, Oak Ridge, TN (United States); Joint Institute for Heavy Ion Research, Oak Ridge, TN (United States); Nazarewicz, W. [University of Tennessee, Department of Physics and Astronomy, Knoxville, TN (United States); Oak Ridge National Laboratory, Physics Division, Oak Ridge, TN (United States); Warsaw University, Institute of Theoretical Physics, Warsaw (Poland); Ploszajczak, M.; Rotureau, J. [CEA/DSM-CNRS/IN2P3, Grand Accelerateur National d' Ions Lourds (GANIL), Caen (France)

    2005-09-01

    A consistent description of weakly bound and unbound nuclei requires an accurate description of the particle continuum properties when carrying out multiconfiguration mixing. This is the domain of the Gamow Shell Model (GSM) which is the multiconfigurational shell model in the complex k-plane formulated using a complete Berggren ensemble representing bound single-particle (s.p.) states, s.p. resonances, and non-resonant complex energy continuum states. We discuss the salient features of effective interactions in weakly bound systems and show selected applications of the GSM formalism to p-shell nuclei. Finally, a development of the new non-perturbative scheme based on Density Matrix Renormalization Group methods to select the most significant continuum configurations in GSM calculations is discussed shortly. (orig.)

  8. Neural correlates of the empathic perceptual processing of realistic social interaction scenarios displayed from a first-order perspective.

    Science.gov (United States)

    Fehr, T; Achtziger, A; Roth, G; Strüber, D

    2014-10-02

    The neural processing of impulsive behavior is a central topic in various clinical and non-clinical contexts. To investigate neural and behavioral correlates of the empathic processing of complex social scenarios, especially considering ecological validity of the experimental procedure, we developed and investigated a video stimulus inventory. It includes realistic neutral, social-positive, and reactive-aggressive action scenarios. Short video-clips showing these social scenarios from a first-person perspective triggering different emotional states were presented to a non-clinical sample of 20 young adult male participants during fMRI measurements. Both affective interaction conditions (social-positive and reactive-aggressive) were contrasted against a neutral baseline condition and against each other. Behavioral evaluation data largely confirmed the validity of the emotion-inducing stimulus material. Reactive-aggressive and social-positive interaction scenarios produced widely overlapping fMRI activation patterns in hetero-modal association cortices, but also in subcortical regions, such as the peri-aqueductal gray. Reactive-aggressive compared to social-positive scenarios yielded a more anterior distribution of activations in pre-motor and inferior frontal brain regions associated to motor-preparation and inhibitory control processing as well as in the insula associated to pain- and/or aversion-processing. We argue that there are both principally common neural networks recruited for the processing of reactive-aggressive and social-positive scenarios, but also exclusive network parts in particular involved depending on individual socialization. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. 35,37,39S isotopes in sd-pf space: Shell-model interpretation

    Science.gov (United States)

    Saxena, A.; Srivastava, P. C.; Hirsch, J. G.; Kota, V. K. B.; Ermamatov, M. J.

    2017-05-01

    The structure of 35,37,39S isotopes is described by performing comprehensive shell model calculations with SDPF-U and SDPFMW interactions. Protons and neutrons are restricted to the sd-shell for N 20. Natural parity states are described by only in-shell mixing, unnatural parity states with 1p-1h inter-shell neutron excitations. With SDPF-U interaction, reported are the results for natural parity states only because this interaction is not suitable for cross shell excitations. Calculated energy levels, electromagnetic properties and spectroscopic factors are in good agreement with the recently available experimental data.

  10. Monte Carlo shell model studies with massively parallel supercomputers

    Science.gov (United States)

    Shimizu, Noritaka; Abe, Takashi; Honma, Michio; Otsuka, Takaharu; Togashi, Tomoaki; Tsunoda, Yusuke; Utsuno, Yutaka; Yoshida, Tooru

    2017-06-01

    We present an overview of the advanced Monte Carlo shell model (MCSM), including its recent applications to no-core shell-model calculations and to large-scale shell-model calculations (LSSM) in the usual sense. For the ab initio no-core MCSM we show recent methodological developments, which include the evaluation of energy eigenvalues in an infinitely large model space by an extrapolation method. As an example of the application of the no-core MCSM, the cluster structure of Be isotopes is discussed. Regarding LSSM applications, the triple shape coexistence in 68Ni and 70Ni and the shape transition of Zr isotopes are clarified with the visualization of the intrinsic deformation of the MCSM wave function. General aspects of the code development of the MCSM on massively parallel computers are also briefly described.

  11. Decaying and kicked turbulence in a shell model

    DEFF Research Database (Denmark)

    Hooghoudt, Jan Otto; Lohse, Detlef; Toschi, Federico

    2001-01-01

    Decaying and periodically kicked turbulence are analyzed within the Gledzer–Ohkitani–Yamada shell model, to allow for sufficiently large scaling regimes. Energy is transferred towards the small scales in intermittent bursts. Nevertheless, mean field arguments are sufficient to account for the ens......Decaying and periodically kicked turbulence are analyzed within the Gledzer–Ohkitani–Yamada shell model, to allow for sufficiently large scaling regimes. Energy is transferred towards the small scales in intermittent bursts. Nevertheless, mean field arguments are sufficient to account...

  12. Shell model calculation for Te and Sn isotopes in the vicinity of {sup 100}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Yakhelef, A.; Bouldjedri, A. [Physics Department, Farhat abbas University, Setif (Algeria); Physics Department, Hadj Lakhdar University, Batna (Algeria)

    2012-06-27

    New Shell Model calculations for even-even isotopes {sup 104-108}Sn and {sup 106,108}Te, in the vicinity of {sup 100}Sn have been performed. The calculations have been carried out using the windows version of NuShell-MSU. The two body matrix elements TBMEs of the effective interaction between valence nucleons are obtained from the renormalized two body effective interaction based on G-matrix derived from the CD-bonn nucleon-nucleon potential. The single particle energies of the proton and neutron valence spaces orbitals are defined from the available spectra of lightest odd isotopes of Sb and Sn respectively.

  13. Mayer–Jensen Shell Model and Magic Numbers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Mayer-Jensen Shell Model and Magic Numbers - An Independent Nucleon Model with Spin-Orbit Coupling. R Velusamy. General Article Volume 12 Issue 12 December 2007 pp 12-24 ...

  14. The continuum shell-model neutron states of Pb

    Indian Academy of Sciences (India)

    model states with the collective vibrational states from giant resonances. The particle-vibration coupling model can be applied to understand the spreading pattern of the shell-model states lying in continuum region. The single-particle states are ...

  15. Final Report Fermionic Symmetries and Self consistent Shell Model

    Energy Technology Data Exchange (ETDEWEB)

    Larry Zamick

    2008-11-07

    In this final report in the field of theoretical nuclear physics we note important accomplishments.We were confronted with "anomoulous" magnetic moments by the experimetalists and were able to expain them. We found unexpected partial dynamical symmetries--completely unknown before, and were able to a large extent to expain them.The importance of a self consistent shell model was emphasized.

  16. Deformed shell model studies of spectroscopic properties of Zn and ...

    Indian Academy of Sciences (India)

    2014-04-05

    Apr 5, 2014 ... pp. 757–767. Deformed shell model studies of spectroscopic properties of. 64. Zn and. 64. Ni and the positron double beta decay of. 64. Zn. R SAHU1,∗ and V K B KOTA2,3. 1Physics Department, Berhampur University, Berhampur 760 007, India. 2Physical Research Laboratory, Ahmedabad 380 009, India.

  17. Variability in shell models of GRBs

    Science.gov (United States)

    Sumner, M. C.; Fenimore, E. E.

    1997-01-01

    Many cosmological models of gamma-ray bursts (GRBs) assume that a single relativistic shell carries kinetic energy away from the source and later converts it into gamma rays, perhaps by interactions with the interstellar medium or by internal shocks within the shell. Although such models are able to reproduce general trends in GRB time histories, it is difficult to reproduce the high degree of variability often seen in GRBs. The authors investigate methods of achieving this variability using a simplified external shock model. Since the model emphasizes geometric and statistical considerations, rather than the detailed physics of the shell, it is applicable to any theory that relies on relativistic shells. They find that the variability in GRBs gives strong clues to the efficiency with which the shell converts its kinetic energy into gamma rays.

  18. Neutrino-Nucleus Reactions - Shell Model vs R.P.A.

    Science.gov (United States)

    Robinson, Shadow; Mekjian, Aram; Zamick, Larry; Auerbach, Naftali

    2001-10-01

    We discuss the virtues and limitations of various approaches to neutrino-nucleus reactions using as an example ν +^12C arrow ^12N+e^-. In the spherical R.P.A., which has often been used, the exclusive reaction rate to the J=1^+ T=1 ground state of ^12N is overestimated by at least a factor of four. This can be explained by deformation effects by using a Nilsson model, or by configuration mixing in the shell model. For the operator rY^1t+ (dipole), r[Y^1s]^λt+ (spin-dipole), and r[Y^1l]^λt+ (orbital-dipole) the summed strength is independent of deformation in a Δ N =0 approximation. This can be explained by using energy weighted sum rules(EWS), plus the fact that for the \\underlinedipole case, the excitation crosses over only one major shell. Thus one can get a good estimate of the non-energy weighted sum strength by dividing EWS by hbar ω. The sum rule for the dipole due to Lipparini and Stingari is 1/2 [EWS(+)+EWS(-)]=9/16 π frachbar^2M A which for N=Z nuclei gives EWS(+)=EWS(-)=9/16 π frachbar^2M A. The spin-dipole strength is 3/4 of the above dipole strength. The above expressions will be modified by exchange current effects which have yet to be calculated. The Primakoff sum rule approach to muon capture can be extended to neutrino interactions and these results can be compared with the shell model and RPA results. In the shell model one has to truncate at a certain level so it is not clear if all the strength has been included. Another problem is self consistency. In the Hartee Fock (HF) theory there will be no admixture of the giant monopole state into the ground state, but in many shell model calculations such admixtures are often very large. One of us (N.A.) has shown that one gets better results in the shell model calculations when H.F. wave functions are used.

  19. Bursts and shocks in a continuum shell model

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Bohr, Tomas; Jensen, M.H.

    1998-01-01

    We study a burst event, i.e., the evolution of an initial condition having support only in a finite interval of k-space, in the continuum shell model due to Parisi. We show that the continuum equation without forcing or dissipation can be explicitly written in characteristic form and that the right...... and left moving parts can be solved exactly. When this is supplemented by the approximate shock condition it is possible to find the symptotic form of the burst....

  20. No-Core Shell Model for 48-Ca, 48-Sc and 48-Ti

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, S; Stoica, S; Vary, J P; Navratil, P

    2004-10-26

    The authors report the first no-core shell model results for {sup 48}Ca, {sup 48}Sc and {sup 48}Ti with derived and modified two-body Hamiltonians. We use an oscillator basis with a limited {bar h}{Omega} range around 40/A{sup 1/3} = 11 MeV and a limited model space up to 1 {bar h}{Omega}. No single-particle energies are used. They find that the charge dependence of the bulk binding energy of eight A = 48 nuclei is reasonably described with an effective Hamiltonian derived from the CD-Bonn interaction while there is an overall underbinding by about 0.4 MeV/nucleon. However, resulting spectra exhibit deficiencies that are anticipated due to: (1) basis space limitations and/or the absence of effective many-body interactions; and, (2) the absence of genuine three-nucleon interactions. They introduce phenomenological modifications to obtain fits to total binding and low-lying spectra. The resulting no-core shell model opens a path for applications to experiments such as the double-beta ({beta}{beta}) decay process.

  1. Four-body calculation of {sup 4}{sub {lambda}}H and {sup 4}{sub {lambda}}He with realistic Y N and N N interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hiyama, E

    2000-05-08

    We carried out four-body calculations of {sup 4}{sub {lambda}}H and {sup 4}{sub {lambda}}He taking both the 3N + {lambda} and 3N + {sigma} channels explicitly with the use of realistic N N and Y N interactions. The {sigma}-channel component plays an important role in binding energies of the A = 4 hypernuclei though the admixture is approximately 1%. The {lambda}N - {sigma}N coupling is found to be of central-force type in the Nijmegen model D and of tensor-force type in the model F.

  2. CrashEd--A Live Immersive, Learning Experience Embedding STEM Subjects in a Realistic, Interactive Crime Scene

    Science.gov (United States)

    Bassford, Marie L.; Crisp, Annette; O'Sullivan, Angela; Bacon, Joanne; Fowler, Mark

    2016-01-01

    Interactive experiences are rapidly becoming popular via the surge of "escape rooms"; part game and part theatre, the "escape" experience is exploding globally, having gone from zero offered at the outset of 2010 to at least 2800 different experiences available worldwide today. CrashEd is an interactive learning experience that…

  3. Shell-model calculations for p-shell hypernuclei

    OpenAIRE

    Millener, D. J.

    2012-01-01

    The interpretation of hypernuclear gamma-ray data for p-shell hypernuclei in terms of shell-model calculations that include the coupling of Lambda- and Sigma-hypernuclear states is briefly reviewed. Next, Lambda 8Li, Lambda 8Be, and Lambda 9Li are considered, both to exhibit features of Lambda-Sigma coupling and as possible source of observed, but unassigned, hypernuclear gamma rays. Then, the feasibility of measuring the ground-state doublet spacing of Lambda 10Be, which, like Lambda 9Li, co...

  4. Constrained-path quantum Monte Carlo approach for non-yrast states within the shell model

    Energy Technology Data Exchange (ETDEWEB)

    Bonnard, J. [INFN, Sezione di Padova, Padova (Italy); LPC Caen, ENSICAEN, Universite de Caen, CNRS/IN2P3, Caen (France); Juillet, O. [LPC Caen, ENSICAEN, Universite de Caen, CNRS/IN2P3, Caen (France)

    2016-04-15

    The present paper intends to present an extension of the constrained-path quantum Monte Carlo approach allowing to reconstruct non-yrast states in order to reach the complete spectroscopy of nuclei within the interacting shell model. As in the yrast case studied in a previous work, the formalism involves a variational symmetry-restored wave function assuming two central roles. First, it guides the underlying Brownian motion to improve the efficiency of the sampling. Second, it constrains the stochastic paths according to the phaseless approximation to control sign or phase problems that usually plague fermionic QMC simulations. Proof-of-principle results in the sd valence space are reported. They prove the ability of the scheme to offer remarkably accurate binding energies for both even- and odd-mass nuclei irrespective of the considered interaction. (orig.)

  5. Generalized folding model for elastic and inelastic nucleus-nucleus scattering using realistic density dependent nucleon-nucleon interaction

    CERN Document Server

    Khoa, D T

    2000-01-01

    A generalized double-folding model for elastic and inelastic nucleus-nucleus scattering is presented. It is designed to accommodate effective nucleon-nucleon (NN) interactions that depend upon the density of nuclear matter in which the two nucleons are immersed. A recently parametrized density dependent M3Y interaction, based on the G-matrix elements of the Paris NN potential, has been used in the present folding calculation. The effects of knock-on exchange of the interacting nucleon pair are included in an accurate local approximation. Examples of the application of this model to study the refractive elastic and inelastic scattering data of sup 1 sup 2 C+ sup 1 sup 2 C and alpha+ sup 5 sup 8 sup , sup 6 sup 0 Ni systems are presented. A detailed comparison of the use of deformed optical potential (DP) and microscopic folded potential in the analysis of inelastic scattering has shown that the use of DP fails to reproduce the inelastic sup 1 sup 2 C+ sup 1 sup 2 C scattering data measured over a wide angular ...

  6. Analysis of the sup 1 sup 6 O(p,gamma) sup 1 sup 7 F capture reaction using the shell model embedded in the continuum

    CERN Document Server

    Bennaceur, K; Okolowicz, J; Ploszajczak, M

    2000-01-01

    We apply the realistic shell model which includes the coupling between many-particle (quasi-)bound states and the continuum of one-particle scattering states, called the Shell Model Embedded in the Continuum, to the spectroscopy of mirror nuclei: sup 1 sup 7 F and sup 1 sup 7 O, as well as to the description of low energy cross section (the astrophysical S factor) for E1, E2 and M1 components in the capture reaction sup 1 sup 6 O(p,gamma) sup 1 sup 7 F. With the same microscopic input we calculate the phase shifts and differential cross section for the elastic scattering of protons on sup 1 sup 6 O.

  7. Isogeometric shell formulation based on a classical shell model

    KAUST Repository

    Niemi, Antti

    2012-09-04

    This paper constitutes the first steps in our work concerning isogeometric shell analysis. An isogeometric shell model of the Reissner-Mindlin type is introduced and a study of its accuracy in the classical pinched cylinder benchmark problem presented. In contrast to earlier works [1,2,3,4], the formulation is based on a shell model where the displacement, strain and stress fields are defined in terms of a curvilinear coordinate system arising from the NURBS description of the shell middle surface. The isogeometric shell formulation is implemented using the PetIGA and igakit software packages developed by the authors. The igakit package is a Python package used to generate NURBS representations of geometries that can be utilised by the PetIGA finite element framework. The latter utilises data structures and routines of the portable, extensible toolkit for scientific computation (PETSc), [5,6]. The current shell implementation is valid for static, linear problems only, but the software package is well suited for future extensions to geometrically and materially nonlinear regime as well as to dynamic problems. The accuracy of the approach in the pinched cylinder benchmark problem and present comparisons against the h-version of the finite element method with bilinear elements. Quadratic, cubic and quartic NURBS discretizations are compared against the isoparametric bilinear discretization introduced in [7]. The results show that the quadratic and cubic NURBS approximations exhibit notably slower convergence under uniform mesh refinement as the thickness decreases but the quartic approximation converges relatively quickly within the standard variational framework. The authors future work is concerned with building an isogeometric finite element method for modelling nonlinear structural response of thin-walled shells undergoing large rigid-body motions. The aim is to use the model in a aeroelastic framework for the simulation of flapping wings.

  8. Deformed shell model study of event rates for WIMP-73Ge scattering

    Science.gov (United States)

    Sahu, R.; Kota, V. K. B.

    2017-12-01

    The event detection rates for the Weakly Interacting Massive Particles (WIMP) (a dark matter candidate) are calculated with 73Ge as the detector. The calculations are performed within the deformed shell model (DSM) based on Hartree-Fock states. First, the energy levels and magnetic moment for the ground state and two low-lying positive parity states for this nucleus are calculated and compared with experiment. The agreement is quite satisfactory. Then the nuclear wave functions are used to investigate the elastic and inelastic scattering of WIMP from 73Ge; inelastic scattering, especially for the 9/2+ → 5/2+ transition, is studied for the first time. The nuclear structure factors which are independent of supersymmetric model are also calculated as a function of WIMP mass. The event rates are calculated for a given set of nucleonic current parameters. The calculation shows that 73Ge is a good detector for detecting dark matter.

  9. Shell-model Monte Carlo simulations of the BCS-BEC crossover in few-fermion systems

    DEFF Research Database (Denmark)

    Zinner, Nikolaj Thomas; Mølmer, Klaus; Özen, C.

    2009-01-01

    We study a trapped system of fermions with a zero-range two-body interaction using the shell-model Monte Carlo method, providing ab initio results for the low particle number limit where mean-field theory is not applicable. We present results for the N-body energies as function of interaction...... strength, particle number, and temperature. The subtle question of renormalization in a finite model space is addressed and the convergence of our method and its applicability across the BCS-BEC crossover is discussed. Our findings indicate that very good quantitative results can be obtained on the BCS...

  10. Framing the Realist Novel

    OpenAIRE

    Blunden, Ralph

    2017-01-01

    Framing the Realist novel develops a theory of framing the realist novel with a distinction made between internal framing devices and the external frames of ontology and ethics. An encompassing methodological frame of critical rationality is developed. What the realist novel is is discussed in chapter one and a distinction is drawn between the historical period in the second half of the nineteenth century and realism that pervades realist narrative more generally. Chapter three applies the th...

  11. One-proton radioactivity in a typical shell model potential

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Martha Monique Nogueira; Duarte, Sergio Barbosa [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Teruya, Nilton [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Dept. de Fisica

    2011-07-01

    Full text: Half-lives for proton emitter nuclei were determined by using a model based on the quantum-mechanical tunneling mechanism of penetration through a potential barrier. A typical shell model potential which includes the coulomb, spin-orbit and centrifugal contribution generate the barrier. Consequently, it is included the generic transition with any orbital angular moment value for the emitted proton. The nuclear radius and diffuseness parameters are determined as following the systematic also used in Ref. (E.L. Medeiros, M.M.N. Rodrigues, S.B. Duarte, and O.A.P. Tavares, Eur. Phys. J. A 34, 417 (2007) (1997). The depth of the nuclear Wood-Saxon potential was adjusted to reproduce the experimental decay energy of the decay in an attempt to determine the half-lives. The results are compared with that ones obtain by using others potential depth in the literature. The half life of around two tens of already detected proton emitters was determined. Our results are in quite good accordance with the experimental values, in particular, the half-life for the resonances of 11N also are in excellent agreement with microscopic calculations of continuum single-particle resonances in ref. (T. N. Leite, N. Teruya and H. Dias, Int. Jour. Mod. Phys. E, Vol. 11, 1 (2002)) and the experimental data of ref. (J. M. Oliveira Jr. et al., Phys. Rev. Lett. 84, 4056 (2000)). (author)

  12. Remembrances of Maria Goeppert Mayer and the Nuclear Shell Model.

    Science.gov (United States)

    Baranger, Elizabeth

    2013-04-01

    Maria Goeppert Mayer received the Nobel Prize in Physics in 1963 for her work on the nuclear shell model. I knew her in my teens as a close ``friend of the family.'' The Mayers lived a few blocks away in Leonia, New Jersey from 1939 to 1945, across the street in Chicago from 1945 to 1958 and about one mile away in La Jolla, CA from 1960 till her death. Maria held primarily ``vol'' (voluntary) positions during this period, although in Chicago she was half time at Argonne National Laboratory as a Senior Physicist. She joined the University of California at San Diego as a professor in 1960, her first full-time academic position. I will discuss her positive impact on a teenager seriously considering becoming a physicist. I will also discuss briefly the impact of her work on our understanding of the structure of nuclei. Maria Mayer was creative, well educated, with a supportive father and husband, but she was foreign , received her Ph D at the time of the Great Depression, and was one of the few women trained in physics. Her unusual career and her great success is due to her love of physics and her ability as a theoretical physicist.

  13. Fully-coupled fluid-structure interaction simulation of the aortic and mitral valves in a realistic 3D left ventricle model.

    Directory of Open Access Journals (Sweden)

    Wenbin Mao

    Full Text Available In this study, we present a fully-coupled fluid-structure interaction (FSI framework that combines smoothed particle hydrodynamics (SPH and nonlinear finite element (FE method to investigate the coupled aortic and mitral valves structural response and the bulk intraventricular hemodynamics in a realistic left ventricle (LV model during the entire cardiac cycle. The FSI model incorporates valve structures that consider native asymmetric leaflet geometries, anisotropic hyperelastic material models and human material properties. Comparison of FSI results with subject-specific echocardiography data demonstrates that the SPH-FE approach is able to quantitatively predict the opening and closing times of the valves, the mitral leaflet opening and closing angles, and the large-scale intraventricular flow phenomena with a reasonable agreement. Moreover, comparison of FSI results with a LV model without valves reveals substantial differences in the flow field. Peak systolic velocities obtained from the FSI model and the LV model without valves are 2.56 m/s and 1.16 m/s, respectively, compared to the Doppler echo data of 2.17 m/s. The proposed SPH-FE FSI framework represents a further step towards modeling patient-specific coupled LV-valve dynamics, and has the potential to improve our understanding of cardiovascular physiology and to support professionals in clinical decision-making.

  14. The No-Core Gamow Shell Model: Including the continuum in the NCSM

    CERN Document Server

    Barrett, B R; Michel, N; Płoszajczak, M

    2015-01-01

    We are witnessing an era of intense experimental efforts that will provide information about the properties of nuclei far from the line of stability, regarding resonant and scattering states as well as (weakly) bound states. This talk describes our formalism for including these necessary ingredients into the No-Core Shell Model by using the Gamow Shell Model approach. Applications of this new approach, known as the No-Core Gamow Shell Model, both to benchmark cases as well as to unstable nuclei will be given.

  15. Description of Charge Radii in Halo Nuclei Within the Gamow Shell Model

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitriou, G. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Michel, N. [CEA, Saclay, France; Nazarewicz, W. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Ploszajczak, M. [Grand Accelerateur National d' Ions Lourds (GANIL); Rotureau, J. [University of Arizona

    2009-01-01

    The charge radius of the halo nucleus 6He is studied within the framework of the Gamow Shell Model (GSM). The charge radius carries information about the size of the neutron halo, the recoil of the core, and the effective interaction between valence nucleons. The motivation for this work stems from the precise measurements of charge radii in 6,8He, 11Li, and 11Be. For these weakly bound nuclei, the proper treatment of the particle continuum turns out to be crucial. The GSM is a tool that can properly account for the coupling of the continuum space (of both resonant and scattering character) with that of the bound states. We use a GSM Hamiltonian written explicitly in intrinsic coordinates. This guarantees that the core recoil effect is properly described and the spurious center-of-mass motion is removed. According to our calculations for 6He, the charge radius is very sensitive to (i) the halo extent given by the two-neutron separation energy of the system, and (ii) the p3/2 occupation. In particular, we show that the two-body wave function of halo neutrons in 6He should contain ~91% of a p3/2 partial wave to reproduce the charge radius. This observation will help us to construct a GSM effective interaction on the interface of p and sd shells that is needed to describe other halo systems.

  16. Investigating the origin of cyclical wind variability in hot massive stars - II. Hydrodynamical simulations of corotating interaction regions using realistic spot parameters for the O giant ξ Persei

    Science.gov (United States)

    David-Uraz, A.; Owocki, S. P.; Wade, G. A.; Sundqvist, J. O.; Kee, N. D.

    2017-09-01

    OB stars exhibit various types of spectral variability historically associated with wind structures, including the apparently ubiquitous discrete absorption components (DACs). These features have been proposed to be caused either by magnetic fields or non-radial pulsations. In this second paper of this series, we revisit the canonical phenomenological hydrodynamical modelling used to explain the formation of DACs by taking into account modern observations and more realistic theoretical predictions. Using constraints on putative bright spots located on the surface of the O giant ξ Persei derived from high precision space-based broad-band optical photometry obtained with the Microvariability and Oscillations of Stars (MOST) space telescope, we generate 2D hydrodynamical simulations of corotating interaction regions in its wind. We then compute synthetic ultraviolet (UV) resonance line profiles using Sobolev Exact Integration and compare them with historical timeseries obtained by the International Ultraviolet Explorer (IUE) to evaluate if the observed behaviour of ξ Persei's DACs is reproduced. Testing three different models of spot size and strength, we find that the classical pattern of variability can be successfully reproduced for two of them: the model with the smallest spots yields absorption features that are incompatible with observations. Furthermore, we test the effect of the radial dependence of ionization levels on line driving, but cannot conclusively assess the importance of this factor. In conclusion, this study self-consistently links optical photometry and UV spectroscopy, paving the way to a better understanding of cyclical wind variability in massive stars in the context of the bright spot paradigm.

  17. Neutrinoless double beta nuclear matrix elements around mass 80 in the nuclear shell-model

    Directory of Open Access Journals (Sweden)

    Yoshinaga N.

    2015-01-01

    Full Text Available The observation of the neutrinoless double-beta decay can determine whether the neutrino is a Majorana particle or not. For theoretical nuclear physics it is particularly important to estimate three types of matrix elements, namely Fermi (F, Gamow-Teller (GT, and tensor (T matrix elements. In this paper, we carry out shell-model calculations and also pair-truncated shell-model calculations to check the model dependence in the case of mass A=82 nuclei.

  18. Importance-truncated no-core shell model for fermionic many-body systems

    Energy Technology Data Exchange (ETDEWEB)

    Spies, Helena

    2017-03-15

    The exact solution of quantum mechanical many-body problems is only possible for few particles. Therefore, numerical methods were developed in the fields of quantum physics and quantum chemistry for larger particle numbers. Configuration Interaction (CI) methods or the No-Core Shell Model (NCSM) allow ab initio calculations for light and intermediate-mass nuclei, without resorting to phenomenology. An extension of the NCSM is the Importance-Truncated No-Core Shell Model, which uses an a priori selection of the most important basis states. The importance truncation was first developed and applied in quantum chemistry in the 1970s and latter successfully applied to models of light and intermediate mass nuclei. Other numerical methods for calculations for ultra-cold fermionic many-body systems are the Fixed-Node Diffusion Monte Carlo method (FN-DMC) and the stochastic variational approach with Correlated Gaussian basis functions (CG). There are also such method as the Coupled-Cluster method, Green's Function Monte Carlo (GFMC) method, et cetera, used for calculation of many-body systems. In this thesis, we adopt the IT-NCSM for the calculation of ultra-cold Fermi gases at unitarity. Ultracold gases are dilute, strongly correlated systems, in which the average interparticle distance is much larger than the range of the interaction. Therefore, the detailed radial dependence of the potential is not resolved, and the potential can be replaced by an effective contact interaction. At low energy, s-wave scattering dominates and the interaction can be described by the s-wave scattering length. If the scattering length is small and negative, Cooper-pairs are formed in the Bardeen-Cooper-Schrieffer (BCS) regime. If the scattering length is small and positive, these Cooper-pairs become strongly bound molecules in a Bose-Einstein-Condensate (BEC). In between (for large scattering lengths) is the unitary limit with universal properties. Calculations of the energy spectra

  19. Ab initio many-body perturbation theory and no-core shell model

    Science.gov (United States)

    Hu, B. S.; Wu, Q.; Xu, F. R.

    2017-10-01

    In many-body perturbation theory (MBPT) we always introduce a parameter N shell to measure the maximal allowed major harmonic-oscillator (HO) shells for the single-particle basis, while the no-core shell model (NCSM) uses N maxℏΩ HO excitation truncation above the lowest HO configuration for the many-body basis. It is worth comparing the two different methods. Starting from “bare” and Okubo-Lee-Suzuki renormalized modern nucleon-nucleon interactions, NNLOopt and JISP16, we show that MBPT within Hartree-Fock bases is in reasonable agreement with NCSM within harmonic oscillator bases for 4He and 16O in “close” model space. In addition, we compare the results using “bare” force with the Okubo-Lee-Suzuki renormalized force. Supported by National Key Basic Research Program of China (2013CB834402), National Natural Science Foundation of China (11235001, 11320101004, 11575007) and the CUSTIPEN (China-U.S. Theory Institute for Physics with Exotic Nuclei) funded by the U.S. Department of Energy, Office of Science (DE-SC0009971)

  20. The specific edge effects of 2D core/shell model for spin-crossover nanoparticles

    Science.gov (United States)

    Muraoka, Azusa; Boukheddaden, Kamel; Linarès, Jorge; Varret, Francois

    2012-02-01

    We analyzed the size effect of spin-crossover nanoparticles at the edges of the 2D square lattices core/shell model, where the edge atoms are constrained to the high spin (HS) state. We performed MC simulations using the Ising-like Hamiltonian, [ H=-J∑(i,j)∑l i'=±1; j'=±1 S( i,j )S( i+i',j+j' ) +( δ2-kBT2g )∑(i,j)S( i,j ) ] The molar entropy change is δS 50J/K/mol, lng=δS/R 6 (R is the perfect gas constant), energy gap is δ=1300K. The HS fixed edges were based on the observation of an increasing residual HS fraction at low temperature upon particle size reduction. This specific boundary condition acts as a negative pressure which shifts downwards the equilibrium temperature. The interplay between the equilibrium temperature (=δ/kBlng) variation and the expected variation of the effective interactions in the system leads to a non-monotonous dependence of the hysteresis loop width upon the particle size. We described how the occurrence condition of the first-order transition has to be adapted to the nanoscale.

  1. Refined 2D and Exact 3D Shell Models for the Free Vibration Analysis of Single- and Double-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Salvatore Brischetto

    2015-12-01

    Full Text Available The present paper talks about the free vibration analysis of simply supported Single- and Double-Walled Carbon Nanotubes (SWCNTs and DWCNTs. Refined 2D Generalized Differential Quadrature (GDQ shell methods and an exact 3D shell model are compared. A continuum approach (based on an elastic three-dimensional shell model is used for natural frequency investigation of SWCNTs and DWCNTs. SWCNTs are defined as isotropic cylinders with an equivalent thickness and Young modulus. DWCNTs are defined as two concentric isotropic cylinders (with an equivalent thickness and Young modulus which can be linked by means of the interlaminar continuity conditions or by means of van der Waals interactions. Layer wise approaches are mandatory for the analysis of van der Waals forces in DWCNTs. The effect of van der Waals interaction between the two cylinders is shown for different DWCNT lengths, diameters and vibration modes. The accuracy of beam models and classical 2D shell models in the free vibration analysis of SWCNTs and DWCNTs is also investigated.

  2. Neutron-proton pairing and double-β decay in the interacting boson model

    Science.gov (United States)

    Van Isacker, P.; Engel, J.; Nomura, K.

    2017-12-01

    Background: The interacting boson model has been used extensively to calculate the matrix elements governing neutrinoless double-β decay. Studies within other models—the shell model, the quasiparticle random-phase approximation, and nuclear energy-density functional theory—indicate that a good description of neutron-proton pairing is essential for accurate calculations of those matrix elements, even though the isotopes used in experiment have significantly more neutrons than protons. The usual interacting boson model is based only on like-particle pairs, however, and the extent to which it captures neutron-proton pairing is not clear. Purpose: To determine whether neutron-proton pairing should be explicitly included as neutron-proton bosons in interacting-boson-model calculations of neutrinoless double-β decay matrix elements. In this paper we restrict ourselves to nuclei in the lower half of the p f shell, where exact shell model calculations are possible. Method: An isospin-invariant version of the nucleon-pair shell model is applied to carry out shell-model calculations in a large space and in a collective subspace, and to define effective operators in the latter. A democratic mapping is then used to define corresponding boson operators for the interacting boson model, with and without an isoscalar neutron-proton pair boson. Results: Interacting-boson-model calculations with and without the isoscalar boson are carried out for nuclei near the beginning of the p f shell, with a realistic shell-model Hamiltonian and neutrinoless double-β -decay operator as the starting point. Energy spectra and double-β matrix elements are compared to those obtained in the underlying shell model. Conclusions: The isoscalar boson is not important for energy spectra but improves the results for the double-β matrix elements. To be useful at the level of precision we need, the mapping procedure must be further developed to better determine the dependence of the boson

  3. Study of fractal features of magnetized plasma through an MHD shell model

    Science.gov (United States)

    Domínguez, M.; Nigro, G.; Muñoz, V.; Carbone, V.

    2017-07-01

    A magnetohydrodynamic (MHD) shell model is used to describe the dissipative events which take place in magnetized plasmas. A scatter plot box-counting fractal dimension D is calculated for the time series of the magnetic energy dissipation rate obtained in the MHD shell model, and the correlation between D and the energy dissipation rate is analyzed. We show that, depending on the values of the viscosity and the diffusivity, the fractal dimension and the occurrence of bursts exhibit correlations similar to those observed in previous studies.

  4. A large-space shell-model approach to the ground state properties of 16O

    Science.gov (United States)

    Takayanagi, K.; Lipparini, E.

    1991-05-01

    We perform a large-space shell-model calculation of the non-local one-body density of 16O which takes into account the two-particle-two-hole correlations in the ground state. An application is done to a simultaneous study of the matter and momentum distributions and the occupation numbers of particle levels.

  5. On The Estimation of Parameters of Thick Current Shell Model of ...

    African Journals Online (AJOL)

    For the first time the five parameters required to fully describe the Onwumechili\\'s composite thick current shell model format of equatorial electrojet have been evaluated from a single autonomous set of ground data at solar minimum. The non-linear model was applied to four data points, each with a pair of simultaneously ...

  6. Theory of the two-proton radioactivity in the continuum shell model

    OpenAIRE

    Rotureau, J.; Okolowicz, J.; Ploszajczak, M.

    2005-01-01

    We develop the microscopic description of the two-nucleon radioactivity in the framework of the Shell Model Embedded in the Continuum. This approach is applied for the description of spontaneous two-proton radioactivity in $^{45}$Fe, $^{48}$Ni and $^{54}$Zn.

  7. Theory of the two-proton radioactivity in the continuum shell model

    Energy Technology Data Exchange (ETDEWEB)

    Rotureau, J. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen cedex 05 (France); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Physics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Joint Institute for Heavy-Ion Research, Oak Ridge, TN 37831 (United States); Okolowicz, J. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen cedex 05 (France); Physics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Ploszajczak, M. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen cedex 05 (France)]. E-mail: ploszajcak@ganil.fr

    2006-03-06

    We develop the microscopic description of the two-nucleon radioactivity in the framework of the shell model embedded in the continuum. This approach is applied for the description of spontaneous two-proton radioactivity in {sup 45}Fe, {sup 48}Ni and {sup 54}Zn.

  8. The No Core Gamow Shell Model for ab-initio Nuclear Structure Calculations

    Directory of Open Access Journals (Sweden)

    Papadimitriou G.

    2014-03-01

    Full Text Available We apply the Berggren basis in a No-Core Shell Model framework to calculate ground state (g.s. energies of 3H, 4He and 5He. In our studies we use the Argonne υ18 and the chiral N3LO potentials, both of which are renormalized via a Vlow−k process.

  9. On two-dimensionalization of three-dimensional turbulence in shell models

    DEFF Research Database (Denmark)

    Chakraborty, Sagar; Jensen, Mogens Høgh; Sarkar, A.

    2010-01-01

    Applying a modified version of the Gledzer-Ohkitani-Yamada (GOY) shell model, the signatures of so-called two-dimensionalization effect of three-dimensional incompressible, homogeneous, isotropic fully developed unforced turbulence have been studied and reproduced. Within the framework of shell...

  10. How the viscous subrange determines inertial range properties in turbulence shell models

    NARCIS (Netherlands)

    Schoerghofer, N.; Kadanoff, L.; Lohse, Detlef

    1995-01-01

    We calculate static solutions of the `GOY¿ shell model of turbulence and do a linear stability analysis. The asymptotic limit of large Reynolds numbers is analyzed. A phase diagram is presented which shows the range of stability of the static solution. We see an unexpected oscillatory dependence of

  11. On large-scale shell-model calculations in sup 4 He

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, R.F.; Flynn, M.F. (Manchester Univ. (UK). Inst. of Science and Technology); Bosca, M.C.; Buendia, E.; Guardiola, R. (Granada Univ. (Spain). Dept. de Fisica Moderna)

    1990-03-01

    Most shell-model calculations of {sup 4}He require very large basis spaces for the energy spectrum to stabilise. Coupled cluster methods and an exact treatment of the centre-of-mass motion dramatically reduce the number of configurations. We thereby obtain almost exact results with small bases, but which include states of very high excitation energy. (author).

  12. Kuhn: Realist or Antirealist?

    Directory of Open Access Journals (Sweden)

    Michel Ghins

    1998-06-01

    Full Text Available Although Kuhn is much more an antirealist than a realist, the earlier and later articulations of realist and antirealist ingredients in his views merit close scrutiny. What are the constituents of the real invariant World posited by Kuhn and its relation to the mutable paradigm-related worlds? Various proposed solutions to this problem (dubbed the "new-world problem" by Ian Hacking are examined and shown to be unsatisfactory. In The Structure of Scientific Revolutions, the stable World can reasonably be taken to be made up of ordinary perceived objects, whereas in Kuhn's later works the transparadigmatic World is identified with something akin to the Kantian world-in-itself. It is argued that both proposals are beset with insuperable difficulties which render Kuhn's earlier and later versions of antirealism implausible.

  13. Kinematic arguments against single relativistic shell models for GRBs

    Science.gov (United States)

    Fenimore, Edward E.; Ramirez, E.; Sumner, M. C.

    1997-01-01

    Two main types of models have been suggested to explain the long durations and multiple peaks of Gamma Ray Bursts (GRBs). In one, there is a very quick release of energy at a central site resulting in a single relativistic shell that produces peaks in the time history through its interactions with the ambient material. In the other, the central site sporadically releases energy over hundreds of seconds forming a peak with each burst of energy. The authors show that the average envelope of emission and the presence of gaps in GRBs are inconsistent with a single relativistic shell. They estimate that the maximum fraction of a single shell that can produce gamma-rays in a GRB with multiple peaks is 10(exp (minus)3), implying that single relativistic shells require 10(exp 3) times more energy than previously thought. They conclude that either the central site of a GRB must produce (approx)10(exp 51) erg/s(exp (minus)1) for hundreds of seconds, or the relativistic shell must have structure on a scales the order of (radical)(epsilon)(Gamma)(exp (minus)1), where (Gamma) is the bulk Lorentz factor ((approximately)10(exp 2) to 10(exp 3)) and (epsilon) is the efficiency.

  14. High-spin states and lifetimes in 33S and shell-model interpretation in the s d -f p space

    Science.gov (United States)

    Aydin, S.; Ionescu-Bujor, M.; Gavrilov, G. Tz.; Dimitrov, B. I.; Lenzi, S. M.; Recchia, F.; Tonev, D.; Bouhelal, M.; Kavillioglu, F.; Pavlov, P.; Bazzacco, D.; Bizzeti, P. G.; Bizzeti-Sona, A. M.; de Angelis, G.; Deloncle, I.; Farnea, E.; Gadea, A.; Gottardo, A.; Goutev, N.; Haas, F.; Huyuk, T.; Laftchiev, H.; Lunardi, S.; Marinov, Tz. K.; Mengoni, D.; Menegazzo, R.; Michelagnoli, C.; Napoli, D. R.; Petkov, P.; Sahin, E.; Singh, P. P.; Stefanova, E. A.; Ur, C. A.; Valiente-Dobón, J. J.; Yavahchova, M. S.

    2017-08-01

    The structure of the 33S nucleus was investigated in the 24Mg(14N,α p ) fusion-evaporation reaction using a 40-MeV 14N beam. The level scheme was extended up to an excitation energy of 11.7 MeV and spin 19 /2+ . Lifetimes of the intermediate- and high-spin states have been investigated by the Doppler shift attenuation method. Data were compared with different shell-model calculations where effective interactions involving two main shells, the sd and the fp, are used.

  15. Dynamo onset as a first-order transition: lessons from a shell model for magnetohydrodynamics.

    Science.gov (United States)

    Sahoo, Ganapati; Mitra, Dhrubaditya; Pandit, Rahul

    2010-03-01

    We carry out systematic and high-resolution studies of dynamo action in a shell model for magnetohydrodynamic (MHD) turbulence over wide ranges of the magnetic Prandtl number PrM and the magnetic Reynolds number ReM. Our study suggests that it is natural to think of dynamo onset as a nonequilibrium first-order phase transition between two different turbulent, but statistically steady, states. The ratio of the magnetic and kinetic energies is a convenient order parameter for this transition. By using this order parameter, we obtain the stability diagram (or nonequilibrium phase diagram) for dynamo formation in our MHD shell model in the (PrM-1,ReM) plane. The dynamo boundary, which separates dynamo and no-dynamo regions, appears to have a fractal character. We obtain a hysteretic behavior of the order parameter across this boundary and suggestions of nucleation-type phenomena.

  16. Level densities of heavy nuclei in the shell model Monte Carlo approach

    Directory of Open Access Journals (Sweden)

    Alhassid Y.

    2016-01-01

    Full Text Available Nuclear level densities are necessary input to the Hauser-Feshbach theory of compound nuclear reactions. However, the microscopic calculation of level densities in the presence of correlations is a challenging many-body problem. The configurationinteraction shell model provides a suitable framework for the inclusion of correlations and shell effects, but the large dimensionality of the many-particle model space has limited its application in heavy nuclei. The shell model Monte Carlo method enables calculations in spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods and has proven to be a powerful tool in the microscopic calculation of level densities. We discuss recent applications of the method in heavy nuclei.

  17. Shell model for time-correlated random advection of passive scalars

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Muratore-Ginanneschi, P.

    1999-01-01

    We study a minimal shell model for the advection of a passive scalar by a Gaussian time-correlated velocity field. The anomalous scaling properties of the white noise limit are studied analytically. The effect of the time correlations are investigated using perturbation theory around the white...... noise limit and nonperturbatively by numerical integration. The time correlation of the velocity field is seen to enhance the intermittency of the passive scalar. [S1063-651X(99)07711-9]....

  18. A shell model approach of the stability of nuclei against nucleon emission

    CERN Document Server

    Calboreanu, A

    1976-01-01

    The stability of nuclei with respect to nucleon emission is discussed in the frame of the shell model. It is assumed that a central potential of Woods-Saxon type capable of reproducing correctly and systematically the location of the single particle energies in the neighbourhood of the Fermi level for a large range of nuclei is capable of predicting those instances when the available bound states cannot accommodate more nucleons. (15 refs).

  19. Calculated Electronic Behavior and Spectrum of Mg+@C60 Using a Simple Jellium-shell Model

    Directory of Open Access Journals (Sweden)

    H. A. Schuessler

    2004-11-01

    Full Text Available Abstract: We present a method for calculating the energy levels and wave functions of any atom or ion with a single valence electron encapsulated in a Fullerene cage using a jelluim-shell model. The valence electron-core interaction is represented by a one-body pseudo-potential obtained through density functional theory with strikingly accurate parameters for Mg+ and which reduces to a purely Coulombic interaction in the case of H. We find that most energy states are affected little by encapsulation. However, when either the electron in the non-encapsulated species has a high probability of being near the jellium cage, or when the cage induces a maximum electron probability density within it, the energy levels shift considerably. Mg+ shows behavior similar to that of H, but since its wave functions are broader, the changes in its energy levels from encapsulation are slightly more pronounced. Agreement with other computational work as well as experiment is excellent and the method presented here is generalizable to any encapsulated species where a one-body electronic pseudo-potential for the free atom (or ion is available. Results are also presented for off-center hydrogen, where a ground state energy minimum of -14.01 eV is found at a nuclear displacement of around 0.1 Å.

  20. Four-body calculation of {sub {Lambda}}{sup 4}H and {sub {Lambda}}{sup 4}He with realistic {Lambda}N interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hiyama, E.; Kamimura, M. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Motoba, T. [Lab. of Physics, Osaka Electro-Communication Univ., Neyagawa (Japan); Yamada, T. [Lab. of Physics, Kanto Gakuin Univ., Yokohama (Japan); Yamamoto, Y. [Physics Section, Tsuru Univ., Tsuru Yamanashi (Japan)

    1998-08-24

    We examine the spin-spin part of the existing YN inter actions. For this purpose {sup 4}{sub {Lambda}}H and {sup 4}{sub {Lambda}}He are well suited since both of the spin-doublet states (0{sup +},1{sup +}) are bound and ob served. We report a four-body calculation within the framework of a 3N+{Lambda} model in which the {Sigma}N-channel contribution is renormalized into {Lambda}N interactions. (orig.) 8 refs.

  1. Surface and tectonic consequences of plume-lithosphere interactions in continents: insights from modelling approach based on realistic representation of lithosphere.

    Science.gov (United States)

    Burov, E.; Guillou-Frottier, L.

    2008-12-01

    Plume-Lithosphere Interactions (PLI) are conditioned by plume dynamics but also by complex (visco-elasto- plastic) lithosphere rheology, structure and regional intraplate stress field. In continents, PLI are often identified within extensional or compression geodynamic contexts, near boundaries between younger plates (e.g., orogenic) and older stable plates (e.g., cratons), which represent important geometrical and thermo- rheological barriers that affect plume head emplacement (e.g., Archean West Africa, East Africa, Pannonian - Carpathian system). We address these problems by considering a free-surface thermo-dynamically coupled (continuous phase transforms) thermo-mechanical numerical model of PLI that treats stratified elasto-viscous-plastic (EVP) continental blocks of contrasting properties submitted to regional compression and extension. The results show that: (1) topographic response to PLI is highly different from the predictions of classical convection models, in particular, the commonly expected long-wavelength uplift is short-lived and is replaced by mainly bi-harmonic deformation of 'tectonic- style' (poly-phase basins and uplifts) characterized by two short wavelengths (50-100 and 200-400 km). (2) tectonic deformation due to far-field forces, such as folding, may interact with lithospheric response to PLI, sometimes in a very complex way; (3) in presence of intra-plate boundaries or blocks, plume head flattening is highly asymmetric and can be blocked from one side by older (and colder) lithospheric block, which leads to mechanical decoupling of crust from the mantle lithosphere and cab be accompanied by localized faulting at the margin; (4) the return flow from the plume head results in sub- vertical down-thrusting (delamination) of the lithosphere below the margin, producing vertical cold 'subduction like' boundary that can be traced down to the 400 km depth; (5) plume head flattening and migration towards the younger plate results in concurrent

  2. Interplay between elastic interactions in a core-shell model for spin-crossover nanoparticles

    Science.gov (United States)

    Oubouchou, H.; Slimani, A.; Boukheddaden, K.

    2013-03-01

    A coupled spin deformation model for spin-crossover (SC) materials, consisting of distortable 2D square-shaped lattices, whose sites may be occupied by high-spin (HS) or low-spin (LS) atoms, is studied by Monte Carlo simulations. To be consistent with the experimental studies, we have studied shell-free and core-shell nanoparticles. In the case of shell-free nanoparticles, we constrained the surface of the nanoparticle (one layer) to be in the HS state from the electronic and the elastic point of view because the surface atoms have weaker ligand-field energy than those of the bulk. We then investigated the size effects and found that the thermal hysteresis width ΔT and the transition temperature Teq follow the respective universal laws, ΔT∝(L-L0) and Teq∝ln(L-Lc), where L is the nanoparticle size. These laws hold independently of the sweeping rate of temperature. In a second stage, we studied the effect of a soft shell on the thermal properties of the core shell nanoparticle for which we have investigated the thermodynamic properties at various sizes of the shell. We find that the thermal hysteresis shifts downwards and the corresponding width increases; a result that contrasts with that of shell-free nanoparticles. In addition, we have observed that large shell size widths hinder the domain formation upon the first-order transition, although the transition is still of first order. These behaviors originate from the elastic stress produced by the shell on the bulk of the nanoparticle, and are identified through the spatial distribution of the internal stress upon the thermal transition. Moreover, we studied the effect of the shell size on the relaxation of the photoinduced metastable HS fraction at low temperature. At this end, a preliminary optimization of the structure of the nanoparticle is performed. We then evidenced that increasing the size of the shell results in an acceleration of the relaxation process. This behavior is in excellent agreement with recent data reported on core shell nanoparticles of Prussian Blue analogs.

  3. Onion-shell model for cosmic ray electrons and radio synchrotron emission in supernova remnants

    Science.gov (United States)

    Beck, R.; Drury, L. O.; Voelk, H. J.; Bogdan, T. J.

    1985-01-01

    The spectrum of cosmic ray electrons, accelerated in the shock front of a supernova remnant (SNR), is calculated in the test-particle approximation using an onion-shell model. Particle diffusion within the evolving remnant is explicity taken into account. The particle spectrum becomes steeper with increasing radius as well as SNR age. Simple models of the magnetic field distribution allow a prediction of the intensity and spectrum of radio synchrotron emission and their radial variation. The agreement with existing observations is satisfactory in several SNR's but fails in other cases. Radiative cooling may be an important effect, especially in SNR's exploding in a dense interstellar medium.

  4. Atomic masses above /sup 146/Gd derived from a shell model analysis of high spin states

    CERN Document Server

    Blomqvist, J; Daly, P J; Kleinheinz, P

    1981-01-01

    Using extensive spectroscopic data on high spin states involving aligned valence nucleons in very neutron deficient nuclei above /sup 146/Gd the authors have derived the ground state masses of /sup 146 /Gd, /sup 147,148/Tb, /sup 148,149,150/Dy, /sup 149,150,151/Ho, and /sup 150,151,152/Er from a shell model analysis. The mass values show a pronounced irregularity in the two-proton separation energies at /sup 146/Gd. The results also link nine alpha -decay chains to the known masses. (0 refs).

  5. Negative-parity intruder states of the neutron-rich N=20, Z=14-16 isotones: a 1{Dirac_h}{omega} shell model description

    Energy Technology Data Exchange (ETDEWEB)

    Bouhelal, M. [Universite de Strasbourg, IPHC, CNRS/IN2P3, Strasbourg (France); Universite de Batna, Departement de Physique, Faculte des Sciences, Batna (Algeria); Haas, F.; Caurier, E.; Nowacki, F. [Universite de Strasbourg, IPHC, CNRS/IN2P3, Strasbourg (France); Bouldjedri, A. [Universite de Batna, Departement de Physique, Faculte des Sciences, Batna (Algeria)

    2009-12-15

    In order to get a consistent shell model description of the negative-parity states throughout the sd shell a new interaction (PSDPFB) has been developed. It was derived in the full p-sd-pf model space and is built on existing interactions for the major shells with adjustments of the cross-shell monopoles. The calculated energy spectra for these 1{Dirac_h}{omega} intruder states are compared to experiment for the N=20 neutron-rich isotones {sup 34}Si, {sup 35}P and {sup 36}S. A systematics for the multiplet configuration {nu}(d{sub 3/2}{sup -1}f{sub 7/2}{sup 1}) in even-even isotones from {sup 34}Si to {sup 40}Ca is also presented. (orig.)

  6. Realistic Visualization of Virtual Views

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    that can be impractical and sometime impossible. In addition, the artificial nature of data often makes visualized virtual scenarios not realistic enough. Not realistic in the sense that a synthetic scene is easy to discriminate visually from a natural scene. A new field of research has consequently...

  7. Projected Shell Model Description of Positive Parity Band of 130Pr Nucleus

    Science.gov (United States)

    Singh, Suram; Kumar, Amit; Singh, Dhanvir; Sharma, Chetan; Bharti, Arun; Bhat, G. H.; Sheikh, J. A.

    2018-02-01

    Theoretical investigation of positive parity yrast band of odd-odd 130Pr nucleus is performed by applying the projected shell model. The present study is undertaken to investigate and verify the very recently observed side band in 130Pr theoretically in terms of quasi-particle (qp) configuration. From the analysis of band diagram, the yrast as well as side band are found to arise from two-qp configuration πh 11/2 ⊗ νh 11/2. The present calculations are viewed to have qualitatively reproduced the known experimental data for yrast states, transition energies, and B( M1) / B( E2) ratios of this nucleus. The recently observed positive parity side band is also reproduced by the present calculations. The energy states of the side band are predicted up to spin 25+, which is far above the known experimental spin of 18+ and this could serve as a motivational factor for future experiments. In addition, the reduced transition probability B( E2) for interband transitions has also been calculated for the first time in projected shell model, which would serve as an encouragement for other research groups in the future.

  8. Projected shell model analysis of multi-quasiparticle high-K isomers in sup 1 sup 7 sup 4 Hf

    CERN Document Server

    Zhou Xian Rong; Sun Yang; Long Gui Lu

    2002-01-01

    Multi-quasiparticle high-K states in sup 1 sup 7 sup 4 Hf are studied in the framework of the projected shell model. The calculation reproduces well the observed ground-state band as well as most of the two- and four-quasiparticle rotational bands. Some as yet unobserved high-K isomeric states in sup 1 sup 7 sup 4 Hf are predicted. Possible reasons for the existing discrepancies between calculation and experiment are discussed. It is suggested that the projected shell model may be a useful method for studying multi-quasiparticle high-K isomers and the K-mixing phenomenon in heavy deformed nuclei

  9. RAMESES publication standards: realist syntheses

    Directory of Open Access Journals (Sweden)

    Wong Geoff

    2013-01-01

    Full Text Available Abstract Background There is growing interest in realist synthesis as an alternative systematic review method. This approach offers the potential to expand the knowledge base in policy-relevant areas - for example, by explaining the success, failure or mixed fortunes of complex interventions. No previous publication standards exist for reporting realist syntheses. This standard was developed as part of the RAMESES (Realist And MEta-narrative Evidence Syntheses: Evolving Standards project. The project's aim is to produce preliminary publication standards for realist systematic reviews. Methods We (a collated and summarized existing literature on the principles of good practice in realist syntheses; (b considered the extent to which these principles had been followed by published syntheses, thereby identifying how rigor may be lost and how existing methods could be improved; (c used a three-round online Delphi method with an interdisciplinary panel of national and international experts in evidence synthesis, realist research, policy and/or publishing to produce and iteratively refine a draft set of methodological steps and publication standards; (d provided real-time support to ongoing realist syntheses and the open-access RAMESES online discussion list so as to capture problems and questions as they arose; and (e synthesized expert input, evidence syntheses and real-time problem analysis into a definitive set of standards. Results We identified 35 published realist syntheses, provided real-time support to 9 on-going syntheses and captured questions raised in the RAMESES discussion list. Through analysis and discussion within the project team, we summarized the published literature and common questions and challenges into briefing materials for the Delphi panel, comprising 37 members. Within three rounds this panel had reached consensus on 19 key publication standards, with an overall response rate of 91%. Conclusion This project used multiple

  10. On Spectral Laws of 2D-Turbulence in Shell Models

    CERN Document Server

    Frick, P; Frick, Peter; Aurell, Erik

    1993-01-01

    We consider a class of shell models of 2D-turbulence. They conserve inertially the analogues of energy and enstrophy, two quadratic forms in the shell amplitudes. Inertially conserving two quadratic integrals leads to two spectral ranges. We study in detail the one characterized by a forward cascade of enstrophy and spectrum close to Kraichnan's $k^{-3}$--law. In an inertial range over more than 15 octaves, the spectrum falls off as $k^{-3.05\\pm 0.01}$, with the same slope in all models. We identify a ``spurious'' intermittency effect, in that the energy spectrum over a rather wide interval adjoing the viscous cut-off, is well approximated by a power-law with fall-off significantly steeper than $k^{-3}$.

  11. Application of Nonlocal Elasticity Shell Model for Axial Buckling of Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Farzad Khademolhosseini

    2009-10-01

    Full Text Available Recently, nano devices have been developed which use Carbon Nanotubes (CNTs as structural elements. To define the range of applicability of CNTs in such devices, it is important to investigate failure modes such as the axial buckling limit. Classical continuum models are inaccurate as they are unable to account for the size-effects in such devices. In this work, a modified nonlocal continuum shell model for the axial buckling of CNTs is proposed and compared with a nonlocal model for torsional buckling. This is done through modifying classical continuum models by incorporating basic concepts from nonlocal elasticity. Furthermore, molecular dynamics (MD simulations are performed on a range of nanotubes with different diameters. Compared to classical models, the modified nonlocal models provide a much better fit to MD simulation results. Using MD simulation results for axial buckling, values of the nonlocal constant and shell thickness are calculated.

  12. Independent clusters in coordinate space: an efficient alternative to shell-model expansions

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, R.F. (Manchester Univ. (UK). Inst. of Science and Technology); Buendia, E. (Granada Univ. (Spain). Dept. de Fisica Moderna); Flynn, M.F.; Guardiola, R. (Valencia Univ. (Spain). Dept. de Fisica Nuclear)

    1991-06-01

    A previous shell-model-style calculation for the ground-state energy of the {sup 4}He nucleus, based on coupled cluster techniques, was able to treat exactly the centre-of-mass motion. It is now recast in a precisely equivalent but vastly more computationally efficient form, directly in terms of coordinate-space correlation functions which are expanded in a Gaussian geminal basis and determined variationally. This reformulation further leads in a straightforward manner to a natural procedure for including higher-order correlations. Its implementation at even the simplest level produces a significant improvement in the already very good upper bounds achieved for the ground-state energy. Further extensions are also discussed. (author).

  13. Shell model description of E 3 transition strengths from the first 3- states in s d -shell even-even nuclei

    Science.gov (United States)

    Bouhelal, M.; Labidi, M.; Haas, F.; Caurier, E.

    2017-10-01

    The electric-octupole E 3 transition strengths from the first 3- state to the ground-state transition in s d shell even-even nuclei with A =16 to 40 are investigated within the shell model framework using the effective (0+1)ℏ ω PSDPF interaction. For this type of transition, new effective charges for protons and neutrons have been determined. Their values 1.36 e for protons and 0.48 e for neutrons are close to those obtained previously for electric-quadrupole E 2 transitions in s d shell nuclei. The calculated E 3 transition strengths from the 31 -→0gs + transitions are compared to a compilation of experimental E 3 data for even-even nuclei throughout the s d shell.

  14. A large-space shell-model approach to the ground state properties of sup 16 O

    Energy Technology Data Exchange (ETDEWEB)

    Takayanagi, K. (Tokyo Denki Univ., Hatoyama, Saitama (Japan). Dept. of Mathematical Sciences); Lipparini, E. (Trento Univ. (Italy). Dipartimento di Fisica)

    1991-05-23

    We perform a large-space shell-model calculation of the non-local one-body density of {sup 16}O which takes into account the two-particle-two-hole correlations in the ground state. An application is done to a simultaneous study of the matter and momentum distributions and the occupation numbers of particle levels. (orig.).

  15. Should scientific realists be platonists?

    DEFF Research Database (Denmark)

    Busch, Jacob; Morrison, Joe

    2015-01-01

    Enhanced Indispensability Arguments (EIA) claim that Scientific Realists are committed to the existence of mathematical entities due to their reliance on Inference to the Best Explana- tion (IBE). Our central question concerns this purported parity of reasoning: do people who defend the EIA make...... an appropriate use of the resources of Scientific Realism (in particular, IBE) to achieve platonism? (§2) We argue that just because a variety of different inferential strategies can be employed by Scientific Realists does not mean that ontological conclusions concerning which things we should be Scientific...... Realists about are arrived at by any inferen- tial route which eschews causes (§3), and nor is there any direct pressure for Scientific Real- ists to change their inferential methods (§4). We suggest that in order to maintain inferential parity with Scientific Realism, proponents of EIA need to give...

  16. Assessment and realistic mathematics education

    NARCIS (Netherlands)

    Heuvel-Panhuizen, M.H.A.M. van den

    1996-01-01

    This book describes the consequences of Realistic Mathematics Education (RME) for assessing students’ understanding of mathematics in primary school. RME is the Dutch answer to the worldwide need to reform mathematics education. Changed ideas about mathematics as a school subject, its goals,

  17. Anomalous Scaling from Controlled Closure in a Shell Model of Turbulence

    CERN Document Server

    Lvov, V S; Pomyalov, A; Procaccia, I; L'vov, Victor S.; Pierotti, Daniela; Pomyalov, Anna; Procaccia, Itamar

    1998-01-01

    We present a model of hydrodynamic turbulence for which the program of computing the scaling exponents from first principles can be developed in a controlled fashion. The model consists of $N$ suitably coupled copies of the "Sabra" shell model of turbulence. The couplings are chosen to include two components: random and deterministic, with a relative importance that is characterized by a parameter called $\\epsilon$. It is demonstrated, using numerical simulations of up to 25 copies and 28 shells that in the $N\\to functions whose scaling exponents are anomalous. The theoretical calculation of the scaling exponents follows verbatim the closure procedure suggested recently for the Navier-Stokes problem, with the additional advantage that in the $N\\to procedure. The main result of this paper is a finite and closed set of scale-invariant equations for the 2nd and 3rd order statistical objects of the theory. This set of equations takes into account terms up to order $\\epsilon^4$ and neglects terms of order $\\epsilo...

  18. Realist Criminology and its Discontents

    Directory of Open Access Journals (Sweden)

    Simon Winlow

    2016-09-01

    Full Text Available Critical criminology must move beyond twentieth-century empiricist and idealist paradigms because the concepts and research programmes influenced by these paradigms are falling into obsolescence. Roger Matthews’ recent work firmly advocates this position and helps to set the ball rolling. Here we argue that Matthews’ attempt to use critical realist thought to move Left Realism towards an advanced position can help to put criminology on a sound new footing. However, before this becomes possible numerous philosophical and theoretical issues must be ironed out. Most importantly, critical criminology must avoid political pragmatism and adopt a more critical stance towards consumer culture’s spectacle. A searching analysis of these issues suggests that, ultimately, criminology is weighed down with obsolete thinking to such an extent that to remain intellectually relevant it must move beyond both Left Realism and Critical Realism to construct a new ultra-realist position.

  19. The fractal dimension of cell membrane correlates with its capacitance: A new fractal single-shell model

    Science.gov (United States)

    Wang, Xujing; Becker, Frederick F.; Gascoyne, Peter R. C.

    2010-01-01

    The scale-invariant property of the cytoplasmic membrane of biological cells is examined by applying the Minkowski–Bouligand method to digitized scanning electron microscopy images of the cell surface. The membrane is found to exhibit fractal behavior, and the derived fractal dimension gives a good description of its morphological complexity. Furthermore, we found that this fractal dimension correlates well with the specific membrane dielectric capacitance derived from the electrorotation measurements. Based on these findings, we propose a new fractal single-shell model to describe the dielectrics of mammalian cells, and compare it with the conventional single-shell model (SSM). We found that while both models fit with experimental data well, the new model is able to eliminate the discrepancy between the measured dielectric property of cells and that predicted by the SSM. PMID:21198103

  20. [Realist evaluation for implementation research].

    Science.gov (United States)

    Dupin, Cécile Marie

    2017-04-01

    The realist approach to evaluation can be useful faced with the complexity of health interventions in populations. Implementation is the process by which these interventions are put into practice. Scientific realism can provide an important contribution to the development of programme theories through implementation research, and help to reveal the distal and proximal mechanisms of programmes aimed at combatting social inequalities in healthcare. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. Probabilistic Bisimulation for Realistic Schedulers

    DEFF Research Database (Denmark)

    Eisentraut, Christian; Godskesen, Jens Christian; Hermanns, Holger

    2015-01-01

    . This holds in the classical context of arbitrary schedulers, but it has been argued that this class of schedulers is unrealistically powerful. This paper studies a strictly coarser notion of bisimilarity, which still enjoys these properties in the context of realistic subclasses of schedulers: Trace...... distribution equivalence is implied for partial information schedulers, and compositionality is preserved by distributed schedulers. The intersection of the two scheduler classes thus spans a coarser and still reasonable compositional theory of behavioral semantics....

  2. Simple and Realistic Data Generation

    DEFF Research Database (Denmark)

    Pedersen, Kenneth Houkjær; Torp, Kristian; Wind, Rico

    2006-01-01

    This paper presents a generic, DBMS independent, and highly extensible relational data generation tool. The tool can efficiently generate realistic test data for OLTP, OLAP, and data streaming applications. The tool uses a graph model to direct the data generation. This model makes it very simple...... to generate data even for large database schemas with complex inter- and intra table relationships. The model also makes it possible to generate data with very accurate characteristics....

  3. Coulomb excitation $^{74}$Zn-$^{80}$Zn (N=50): probing the validity of shell-model descriptions around $^{78}$Ni

    CERN Multimedia

    A study of the evolution of the nuclear structure along the zinc isotopic chain close to the doubly magic nucleus $^{78}$Ni is proposed to probe recent shell-model calculations in this area of the nuclear chart. Excitation energies and connecting B(E2) values will be measured through multiple Coulomb excitation experiment with laser ionized purified beams of $^{74-80}$Zn from HIE ISOLDE. The current proposal request 30 shifts.

  4. An efficient size-dependent shear deformable shell model and molecular dynamics simulation for axial instability analysis of silicon nanoshells.

    Science.gov (United States)

    Sahmani, S; Aghdam, M M; Bahrami, M

    2017-10-01

    Understanding the size-dependent behavior of structures at nanoscale is essential in order to have an effective design of nanosystems. In the current investigation, the surface elasticity theory is extended to study the nonlinear buckling and postbuckling response of axially loaded silicon cylindrical naoshells. Thereby, an efficient size-dependent shear deformable shell model is developed including the size effect of surface free energy. A boundary layer theory of shell buckling in conjunction with a perturbation-based solution methodology is employed to predict the size dependency in the buckling loads and postbuckling behavior of silicon nanoshells having various thicknesses. After that, on the basis of the Tersoff empirical potential, a molecular dynamics (MD) simulation is performed for a silicon cylindrical nanoshell with thickness of four times of silicon lattice constant, the critical buckling load and critical shortening of which are extracted and compared with those of the developed non-classical shell model. It is demonstrated that by taking the effects of surface free energy into account, a very good agreement is achieved between the results of the developed size-dependent continuum shell model and those of MD simulation. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Realistic analytical polyhedral MRI phantoms.

    Science.gov (United States)

    Ngo, Tri M; Fung, George S K; Han, Shuo; Chen, Min; Prince, Jerry L; Tsui, Benjamin M W; McVeigh, Elliot R; Herzka, Daniel A

    2016-08-01

    Analytical phantoms have closed form Fourier transform expressions and are used to simulate MRI acquisitions. Existing three-dimensional (3D) analytical phantoms are unable to accurately model shapes of biomedical interest. The goal of this study was to demonstrate that polyhedral analytical phantoms have closed form Fourier transform expressions and can accurately represent 3D biomedical shapes. The Fourier transform of a polyhedron was implemented and its accuracy in representing faceted and smooth surfaces was characterized. Realistic anthropomorphic polyhedral brain and torso phantoms were constructed and their use in simulated 3D and two-dimensional (2D) MRI acquisitions was described. Using polyhedra, the Fourier transform of faceted shapes can be computed to within machine precision. Smooth surfaces can be approximated with increasing accuracy by increasing the number of facets in the polyhedron; the additional accumulated numerical imprecision of the Fourier transform of polyhedra with many faces remained small. Simulations of 3D and 2D brain and 2D torso cine acquisitions produced realistic reconstructions free of high frequency edge aliasing compared with equivalent voxelized/rasterized phantoms. Analytical polyhedral phantoms are easy to construct and can accurately simulate shapes of biomedical interest. Magn Reson Med 76:663-678, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  6. Realistic Real-Time Outdoor Rendering in Augmented Reality

    Science.gov (United States)

    Kolivand, Hoshang; Sunar, Mohd Shahrizal

    2014-01-01

    Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems. PMID:25268480

  7. Realistic real-time outdoor rendering in augmented reality.

    Science.gov (United States)

    Kolivand, Hoshang; Sunar, Mohd Shahrizal

    2014-01-01

    Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems.

  8. Realistic real-time outdoor rendering in augmented reality.

    Directory of Open Access Journals (Sweden)

    Hoshang Kolivand

    Full Text Available Realistic rendering techniques of outdoor Augmented Reality (AR has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps. Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems.

  9. PREFACE: 11th International Spring Seminar on Nuclear Physics: Shell Model and Nuclear Structure - achievements of the past two decades

    Science.gov (United States)

    2015-02-01

    The 11th International Seminar on Nuclear Physics was held in Ischia from May 12 to May 16, 2014. This Seminar was dedicated to Aldo Covello, who has been the promoter of this series of meetings, which started in Sorrento in 1986 and continued with meetings held every two or three years in the Naples area. Aldo's idea was to offer to a group of researchers, actively working in selected fields of Nuclear Physics, the opportunity to confront their points of view in a lively and informal way. The choice for the period of the year, Spring, as well as the sites chosen reflected this intent. The first meeting was of a purely theoretical nature, but it was immediately clear that the scope of these conferences needed to be enlarged calling into play the experimental community. Then, starting from the second meeting, all the following ones have been characterized by fruitful discussion between theoretical and experimental researchers on current achievements and future developments of nuclear structure. This may be read, in fact, as one of the motivating factors for Aldo's election as Fellow of the American Physical Society in 2008 "... for his outstanding contributions to the international nuclear physics community by providing, for over two decades, a venue for theorists and experimentalists to share their latest ideas." The present meeting, organized by Aldo's former students and with the benefit of his suggestions, has maintained this tradition. The title "Shell model and nuclear structure: achievements of the past two decades" recalls that of the 2nd International Spring Seminar "Shell Model and Nuclear Structure: where do we stand?". The main aim of this 11th Seminar was, in fact, to discuss the changes of the past two decades on our view of nuclei in terms of shell structure as well as the perspectives of the shell model, which has been one of the key points in Aldo's research. This point is well accounted by the Opening Speech of Igal Talmi, one of the fathers of the

  10. Σ-admixture in neutron-rich Li Λ hypernuclei in a microscopic shell-model calculation

    Directory of Open Access Journals (Sweden)

    Harada T.

    2010-04-01

    Full Text Available We systematically investigate the structures of the Λ hypernuclei ΛLi with the mass number A = 7–10 in shell-model calculations considering the ΛN -ΣN coupling in the first-order perturbation method. We find that the calculated Σ-mixing probabilities and energy shifts due to the ΛN -ΣN coupling increase with the neutron number. The Fermi-type and Gamow-Teller-type couplings, which are related to the β-transition properties of the nuclear core state, coherently contribute to the energy shift in neutron-rich hypernuclei.

  11. Realistic Simulation of Rice Plant

    Directory of Open Access Journals (Sweden)

    Wei-long DING

    2011-09-01

    Full Text Available The existing research results of virtual modeling of rice plant, however, is far from perfect compared to that of other crops due to its complex structure and growth process. Techniques to visually simulate the architecture of rice plant and its growth process are presented based on the analysis of the morphological characteristics at different stages. Firstly, the simulations of geometrical shape, the bending status and the structural distortion of rice leaves are conducted. Then, by using an improved model for bending deformation, the curved patterns of panicle axis and various types of panicle branches are generated, and the spatial shape of rice panicle is therefore created. Parametric L-system is employed to generate its topological structures, and finite-state automaton is adopted to describe the development of geometrical structures. Finally, the computer visualization of three-dimensional morphologies of rice plant at both organ and individual levels is achieved. The experimental results showed that the proposed methods of modeling the three-dimensional shapes of organs and simulating the growth of rice plant are feasible and effective, and the generated three-dimensional images are realistic.

  12. Shell model based reaction rates for rp-process nuclei in the mass range A=44-63

    CERN Document Server

    Fisker, J L; Görres, J; Langanke, K; Martínez-Pinedo, G; Wiescher, M C

    2001-01-01

    We have used large-scale shell-model diagonalization calculations to determine the level spectra, proton spectroscopic factors, and electromagnetic transition probabilities for proton rich nuclei in the mass range A=44-63. Based on these results and the available experimental data, we calculated the resonances for proton capture reactions on neutron deficient nuclei in this mass range. We also calculated the direct capture processes on these nuclei in the framework of a Woods-Saxon potential model. Taking into account both resonant and direct contributions, we determined the ground-state proton capture reaction rates for these nuclei under hot hydrogen burning conditions for temperatures between 10 sup 8 and 10 sup 1 sup 0 K. The calculated compound-nucleus level properties and the reaction rates are presented here; the rates are also available in computer-readable format from the authors.

  13. Leadership research in healthcare: A realist review.

    Science.gov (United States)

    Lega, Federico; Prenestini, Anna; Rosso, Matilde

    2017-05-01

    Being largely considered a human right, healthcare needs leaders who are able to make choices and to set directions. Following the recommendations expressed by Gilmartin and D'Aunno's review and roadmap compiled in 2008, today, it is important to acknowledge researchers' contributions to outline this landscape. The realist review of 77 publications answered questions such as "what works, for whom, and in which circumstances" highlighting: the effectiveness and acceptance of transformational and collaborative approaches; professionalism, expertise, and good task delegation within operational teams; distributed leadership, relationships, and social responsibility at a systemic level. The relevancy and need of leadership development programs, framed within a wider strategy, emerged. Nonetheless, gaps still exist and require further investigation: particular needs in public vs. private contexts; professionals' and women's differentiating characters; generational gaps; associations between leadership and recruitment HR practices research; how (and if) leaders (should) influence the organizational culture and values; and developing countries specific challenges. Also, a greater proportion of relevant findings should be drawn by empirical and more rigorous studies. Finally, a major attention could be paid to interactions happening at the team, organizational, and systemic level among different leaders and among leaders, followers and external actors.

  14. Quantum Monte Carlo diagonalization method as a variational calculation

    Energy Technology Data Exchange (ETDEWEB)

    Mizusaki, Takahiro; Otsuka, Takaharu [Tokyo Univ. (Japan). Dept. of Physics; Honma, Michio

    1997-05-01

    A stochastic method for performing large-scale shell model calculations is presented, which utilizes the auxiliary field Monte Carlo technique and diagonalization method. This method overcomes the limitation of the conventional shell model diagonalization and can extremely widen the feasibility of shell model calculations with realistic interactions for spectroscopic study of nuclear structure. (author)

  15. Symmetry energies for A =24 and 48 and the USD and KB3 shell model Hamiltonians

    Science.gov (United States)

    Kingan, A.; Neergârd, K.; Zamick, L.

    2017-12-01

    Calculations in the sd and pf shells reported some time ago by Satuła et al. [Phys. Lett. B 407, 103 (1997), 10.1016/S0370-2693(97)00711-9] are redone for an extended analysis of the results. As in the original work, we do calculations for one mass number in each shell and consider in each case the sequence of lowest energies for isospins 0, 2, and 4, briefly the symmetry spectrum. Following further the original work, we study how this spectrum changes when parts of the two-nucleon interaction are turned off. The variation of its width is explored in detail. A differential combination ɛW of the three energies was taken in the original work as a measure of the so-called Wigner term in semiempirical mass formulas, and it was found to decrease drastically when the two-nucleon interaction in the channel of zero isospin is turned off. Our analysis shows that the width of the symmetry spectrum experiences an equally drastic decrease, which can be explained qualitatively in terms of schematic approximations. We therefore suggest that the decrease of ɛW be seen mainly as a side effect of a narrowing of the symmetry spectrum rather than an independent manifestation of the two-nucleon interaction in the channel of zero isospin.

  16. Sotsialistlik realist Keskküla

    Index Scriptorium Estoniae

    1998-01-01

    Londonis 1998. a. ilmunud inglise kunstikriitiku Matthew Cullerne Bowni monograafias "Socialist Realist Painting" on eesti kunstnikest Enn Põldroos, Nikolai Kormashov, Ando Keskküla, Kormashovi ja Keskküla maalide reproduktsioonid

  17. Generating realistic roofs over a rectilinear polygon

    KAUST Repository

    Ahn, Heekap

    2011-01-01

    Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs, and show a connection with the straight skeleton of P. We show that the maximum possible number of distinct realistic roofs over P is ( ⌊(n-4)/4⌋ (n-4)/2) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n 4) preprocessing time. We also present an O(n 5)-time algorithm for computing a realistic roof with minimum height or volume. © 2011 Springer-Verlag.

  18. Toward a Direct Realist Account of Observation.

    Science.gov (United States)

    Sievers, K. H.

    1999-01-01

    Criticizes the account of observation given by Alan Chalmers in "What Is This Thing Called Science?" and provides an alternative based on direct realist approaches to perception. Contains 15 references. (Author/WRM)

  19. Probabilistic infrasound propagation using realistic atmospheric perturbations

    NARCIS (Netherlands)

    Smets, P.S.M.; Evers, L.G.; Näsholm, S.P.; Gibbons, S.J.

    2015-01-01

    This study demonstrates probabilistic infrasound propagation modeling using realistic perturbations. The ensembles of perturbed analyses, provided by the European Centre for Medium-Range Weather Forecasts (ECMWF), include error variances of both model and assimilated observations. Ensemble spread

  20. Toward a Realistic Simulation of Organ Dissection

    OpenAIRE

    Villard, Pierre-Frédéric; Koenig, Nicolas; Perrenot, Cyril; Perez, Manuela; Boshier, Piers

    2014-01-01

    International audience; Whilst laparoscopic surgical simulators are becoming increasingly realistic they cannot, as yet, fully replicate the experience of live surgery. In particular tissue dissection in one task that is particularly challenging to replicate. Limitation of current attempts to simulate tissue dissection include: poor visual rendering; over simplification of the task and; unrealistic tissue properties. In an effort to generate a more realistic model of tissue dissection in lapa...

  1. Realistic Approach for Phasor Measurement Unit Placement

    DEFF Research Database (Denmark)

    Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul

    2015-01-01

    This paper presents a realistic cost-effectivemodel for optimal placement of phasor measurement units (PMUs) for complete observability of a power system considering practical cost implications. The proposed model considers hidden or otherwise unaccounted practical costs involved in PMU installat......This paper presents a realistic cost-effectivemodel for optimal placement of phasor measurement units (PMUs) for complete observability of a power system considering practical cost implications. The proposed model considers hidden or otherwise unaccounted practical costs involved in PMU...

  2. A realistic molecular model of cement hydrates.

    Science.gov (United States)

    Pellenq, Roland J-M; Kushima, Akihiro; Shahsavari, Rouzbeh; Van Vliet, Krystyn J; Buehler, Markus J; Yip, Sidney; Ulm, Franz-Josef

    2009-09-22

    Despite decades of studies of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay between chemical composition and density remains essentially unexplored. Together these characteristics of C-S-H define and modulate the physical and mechanical properties of this "liquid stone" gel phase. With the recent determination of the calcium/silicon (C/S = 1.7) ratio and the density of the C-S-H particle (2.6 g/cm(3)) by neutron scattering measurements, there is new urgency to the challenge of explaining these essential properties. Here we propose a molecular model of C-S-H based on a bottom-up atomistic simulation approach that considers only the chemical specificity of the system as the overriding constraint. By allowing for short silica chains distributed as monomers, dimers, and pentamers, this C-S-H archetype of a molecular description of interacting CaO, SiO2, and H2O units provides not only realistic values of the C/S ratio and the density computed by grand canonical Monte Carlo simulation of water adsorption at 300 K. The model, with a chemical composition of (CaO)(1.65)(SiO2)(H2O)(1.75), also predicts other essential structural features and fundamental physical properties amenable to experimental validation, which suggest that the C-S-H gel structure includes both glass-like short-range order and crystalline features of the mineral tobermorite. Additionally, we probe the mechanical stiffness, strength, and hydrolytic shear response of our molecular model, as compared to experimentally measured properties of C-S-H. The latter results illustrate the prospect of treating cement on equal footing with metals and ceramics in the current application of mechanism-based models and multiscale simulations to study inelastic deformation and cracking.

  3. Realistic roofs over a rectilinear polygon

    KAUST Repository

    Ahn, Heekap

    2013-11-01

    Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. According to this definition, some roofs may have faces isolated from the boundary of P or even local minima, which are undesirable for several practical reasons. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs and show that the straight skeleton induces a realistic roof with maximum height and volume. We also show that the maximum possible number of distinct realistic roofs over P is ((n-4)(n-4)/4 /2⌋) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n4) preprocessing time. We also present an O(n5)-time algorithm for computing a realistic roof with minimum height or volume. © 2013 Elsevier B.V.

  4. Multi-shell model of ion-induced nucleic acid condensation

    Science.gov (United States)

    Tolokh, Igor S.; Drozdetski, Aleksander V.; Pollack, Lois; Onufriev, Alexey V.

    2016-01-01

    We present a semi-quantitative model of condensation of short nucleic acid (NA) duplexes induced by trivalent cobalt(iii) hexammine (CoHex) ions. The model is based on partitioning of bound counterion distribution around single NA duplex into “external” and “internal” ion binding shells distinguished by the proximity to duplex helical axis. In the aggregated phase the shells overlap, which leads to significantly increased attraction of CoHex ions in these overlaps with the neighboring duplexes. The duplex aggregation free energy is decomposed into attractive and repulsive components in such a way that they can be represented by simple analytical expressions with parameters derived from molecular dynamic simulations and numerical solutions of Poisson equation. The attractive term depends on the fractions of bound ions in the overlapping shells and affinity of CoHex to the “external” shell of nearly neutralized duplex. The repulsive components of the free energy are duplex configurational entropy loss upon the aggregation and the electrostatic repulsion of the duplexes that remains after neutralization by bound CoHex ions. The estimates of the aggregation free energy are consistent with the experimental range of NA duplex condensation propensities, including the unusually poor condensation of RNA structures and subtle sequence effects upon DNA condensation. The model predicts that, in contrast to DNA, RNA duplexes may condense into tighter packed aggregates with a higher degree of duplex neutralization. An appreciable CoHex mediated RNA-RNA attraction requires closer inter-duplex separation to engage CoHex ions (bound mostly in the “internal” shell of RNA) into short-range attractive interactions. The model also predicts that longer NA fragments will condense more readily than shorter ones. The ability of this model to explain experimentally observed trends in NA condensation lends support to proposed NA condensation picture based on the multivalent

  5. Multi-shell model of ion-induced nucleic acid condensation.

    Science.gov (United States)

    Tolokh, Igor S; Drozdetski, Aleksander V; Pollack, Lois; Baker, Nathan A; Onufriev, Alexey V

    2016-04-21

    We present a semi-quantitative model of condensation of short nucleic acid (NA) duplexes induced by trivalent cobalt(iii) hexammine (CoHex) ions. The model is based on partitioning of bound counterion distribution around single NA duplex into "external" and "internal" ion binding shells distinguished by the proximity to duplex helical axis. In the aggregated phase the shells overlap, which leads to significantly increased attraction of CoHex ions in these overlaps with the neighboring duplexes. The duplex aggregationfree energy is decomposed into attractive and repulsive components in such a way that they can be represented by simple analytical expressions with parameters derived from molecular dynamic simulations and numerical solutions of Poisson equation. The attractive term depends on the fractions of bound ions in the overlapping shells and affinity of CoHex to the "external" shell of nearly neutralized duplex. The repulsive components of the free energy are duplex configurational entropy loss upon the aggregation and the electrostatic repulsion of the duplexes that remains after neutralization by bound CoHex ions. The estimates of the aggregationfree energy are consistent with the experimental range of NA duplex condensation propensities, including the unusually poor condensation of RNA structures and subtle sequence effects upon DNAcondensation. The model predicts that, in contrast to DNA, RNA duplexes may condense into tighter packed aggregates with a higher degree of duplex neutralization. An appreciable CoHex mediated RNA-RNA attraction requires closer inter-duplex separation to engage CoHex ions (bound mostly in the "internal" shell of RNA) into short-range attractive interactions. The model also predicts that longer NA fragments will condense more readily than shorter ones. The ability of this model to explain experimentally observed trends in NAcondensation lends support to proposed NAcondensation picture based on the multivalent "ion binding shells."

  6. Role of temperature-dependent viscosity and surface plates in spherical shell models of mantle convection

    Science.gov (United States)

    Zhong, Shijie; Zuber, Maria T.; Moresi, Louis; Gurnis, Michael

    2000-05-01

    Layered viscosity, temperature-dependent viscosity, and surface plates have an important effect on the scale and morphology of structure in spherical models of mantle convection. We find that long-wavelength structures can be produced either by a layered viscosity with a weak upper mantle or temperature-dependent viscosity even in the absence of surface plates, corroborating earlier studies. However, combining the layered viscosity structure with a temperature-dependent viscosity results in structure with significantly shorter wavelengths. Our models show that the scale of convection is mainly controlled by the surface plates, supporting the previous two-dimensional studies. Our models with surface plates, layered and temperature-dependent viscosity, and internal heating explain mantle structures inferred from seismic tomography. The models show that hot upwellings initiate at the core-mantle boundary (CMB) with linear structures, and as they depart from CMB, the linear upwellings quickly change into quasi-cylindrical plumes that dynamically interact with the ambient mantle and surface plates while ascending through the mantle. A linear up welling structure is generated again at shallow depths (maintained throughout the mantle. The tendency for linear upwelling and downwelling structures to break into plume-like structures is stronger at higher Rayleigh numbers. Our models also show that downwellings to first-order control surface plate motions and the locations and horizontal motion of upwellings. Upwellings tend to form at stagnation points predicted solely from the buoyancy forces of downwellings. Temperature-dependent viscosity greatly enhances the ascending velocity of developed upwelling plumes, and this may reduce the influence of global mantle flow on the motion of plumes. Our results can explain the anticorrelation between hotspot distribution and fast seismic wave speed anomalies in the lower mantle and may also have significant implications to the

  7. Electromagnetic properties in {sup 160-170}Dy nuclei. A microscopic description by the pseudo-SU(3) shell model

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Carlos E.; Bagatella-Flores, Norma [Universidad Veracruzana, Facultad de Fisica, Veracruz (Mexico); Velazquez, Victor [Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Mexico D.F. (Mexico); Lerma-Hernandez, Sergio [Universidad Veracruzana, Facultad de Fisica, Veracruz (Mexico); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico D.F. (Mexico)

    2017-04-15

    The large collectivity observed in the rare-earth region of the nuclear landscape is well known. The microscopic studies are difficult to perform in this region due to the enormous size of the valence spaces, a problem that can be avoided by means of the use of symmetry-based models. Here we present calculations for electromagnetic properties of {sup 160-170}Dy nuclei within the pseudo-SU(3) scheme. The model Hamiltonian includes the preserving symmetry Q.Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized for all members of the chain. The model is used to calculate B(E2) and B(M1) inter-band transition strengths between the ground state, γ and β-bands. In addition, we present results for quadrupole moments and g factors in these rotational bands. The results show that the pseudo-SU(3) shell model is a powerful microscopic theory for a description of electromagnetic properties of states in the normal parity sector in heavy deformed nuclei. (orig.)

  8. Development of a single cell spherical shell model for an investigation of electrical properties with a computing program

    Directory of Open Access Journals (Sweden)

    Boonlamp, M.

    2005-03-01

    Full Text Available A spherical double shell model (SDM for a single cell has been developed, using Laplace’s equation in spherical coordinates and boundary conditions. Electric field intensities and dielectric constants of each region inside and outside of the cell have been estimated. The dielectrophoretic spectrum of the real part of a complex function (Re[f ( ω] were computed using Visual Foxpro Version 6, which gave calculated values pertaining to electrical properties of the cell model as compared with experimental values. The process was repeated until the error percentile was in an acceptable range. The calculated parameters were the dielectric constants and the conductivities of the inner cytoplasm ( εic, σic, the outer cytoplasm ( εoc, σoc, the inner membrane ( εim, σim, the outer membrane ( εom, σom, the suspending solution( εs, σs and the thickness of each layer (dom, doc, dim, respectively. This computer program provides estimated values of cell electrical properties with high accuracy and required minimal computational time.

  9. Spherical-shell model for the van der Waals coefficients between fullerenes and/or nearly spherical nanoclusters.

    Science.gov (United States)

    Perdew, John P; Tao, Jianmin; Hao, Pan; Ruzsinszky, Adrienn; Csonka, Gábor I; Pitarke, J M

    2012-10-24

    Fullerene molecules such as C(60) are large nearly spherical shells of carbon atoms. Pairs of such molecules have a strong long-range van der Waals attraction that can produce scattering or binding into molecular crystals. A simplified classical-electrodynamics model for a fullerene is a spherical metal shell, with uniform electron density confined between outer and inner radii (just as a simplified model for a nearly spherical metallic nanocluster is a solid metal sphere or filled shell). For the spherical-shell model, the exact dynamic multipole polarizabilities are all known analytically. From them, we can derive exact analytic expressions for the van der Waals coefficients of all orders between two spherical metal shells. The shells can be identical or different, and hollow or filled. To connect the model to a real fullerene, we input the static dipole polarizability, valence electron number and estimated shell thickness t of the real molecule. Our prediction for the leading van der Waals coefficient C(6) between two C(60) molecules ((1.30 ± 0.22) × 10(5) hartree bohr(6)) agrees well with a prediction for the real molecule from time-dependent density functional theory. Our prediction is remarkably insensitive to t. Future work might include the prediction of higher-order (e.g. C(8) and C(10)) coefficients for C(60), applications to other fullerenes or nearly spherical metal clusters, etc. We also make general observations about the van der Waals coefficients.

  10. Suprathermal populations: from observations to realistic interpretation

    Science.gov (United States)

    Lazar, Marian; Fichtner, Horst; Pierrard, Viviane; Poedts, Stefaan; Yoon, Peter

    2017-04-01

    Suprathermal populations enhance the high-energy tails of the velocity distributions of particles in space plasmas. Standard Maxwellian models cannot describe the observed distributions, which are instead well reproduced by the Kappa power-laws. However, the family of Kappa distribution functions do not offer a unique representation of the suprathermals. Here we discuss the efforts made in the last decades to describe realistically these populations and and, implicitly, their effects in the solar wind. A realistic interpretation is conditioned by a rigorous modelling in accord with the observations. In turn, the effects predicted for the same suprathermal populations must also be confirmed by the observations.

  11. Blend Shape Interpolation and FACS for Realistic Avatar

    Science.gov (United States)

    Alkawaz, Mohammed Hazim; Mohamad, Dzulkifli; Basori, Ahmad Hoirul; Saba, Tanzila

    2015-03-01

    The quest of developing realistic facial animation is ever-growing. The emergence of sophisticated algorithms, new graphical user interfaces, laser scans and advanced 3D tools imparted further impetus towards the rapid advancement of complex virtual human facial model. Face-to-face communication being the most natural way of human interaction, the facial animation systems became more attractive in the information technology era for sundry applications. The production of computer-animated movies using synthetic actors are still challenging issues. Proposed facial expression carries the signature of happiness, sadness, angry or cheerful, etc. The mood of a particular person in the midst of a large group can immediately be identified via very subtle changes in facial expressions. Facial expressions being very complex as well as important nonverbal communication channel are tricky to synthesize realistically using computer graphics. Computer synthesis of practical facial expressions must deal with the geometric representation of the human face and the control of the facial animation. We developed a new approach by integrating blend shape interpolation (BSI) and facial action coding system (FACS) to create a realistic and expressive computer facial animation design. The BSI is used to generate the natural face while the FACS is employed to reflect the exact facial muscle movements for four basic natural emotional expressions such as angry, happy, sad and fear with high fidelity. The results in perceiving the realistic facial expression for virtual human emotions based on facial skin color and texture may contribute towards the development of virtual reality and game environment of computer aided graphics animation systems.

  12. Stochastic estimation of nuclear level density in the nuclear shell model: An application to parity-dependent level density in 58Ni

    Directory of Open Access Journals (Sweden)

    Noritaka Shimizu

    2016-02-01

    Full Text Available We introduce a novel method to obtain level densities in large-scale shell-model calculations. Our method is a stochastic estimation of eigenvalue count based on a shifted Krylov-subspace method, which enables us to obtain level densities of huge Hamiltonian matrices. This framework leads to a successful description of both low-lying spectroscopy and the experimentally observed equilibration of Jπ=2+ and 2− states in 58Ni in a unified manner.

  13. The KM phase in semi-realistic heterotic orbifold models

    Energy Technology Data Exchange (ETDEWEB)

    Giedt, Joel

    2000-07-05

    In string-inspired semi-realistic heterotic orbifolds models with an anomalous U(1){sub X},a nonzero Kobayashi-Masakawa (KM) phase is shown to arise generically from the expectation values of complex scalar fields, which appear in nonrenormalizable quark mass couplings. Modular covariant nonrenormalizable superpotential couplings are constructed. A toy Z{sub 3} orbifold model is analyzed in some detail. Modular symmetries and orbifold selection rules are taken into account and do not lead to a cancellation of the KM phase. We also discuss attempts to obtain the KM phase solely from renormalizable interactions.

  14. Satellite Maps Deliver More Realistic Gaming

    Science.gov (United States)

    2013-01-01

    When Redwood City, California-based Electronic Arts (EA) decided to make SSX, its latest snowboarding video game, it faced challenges in creating realistic-looking mountains. The solution was NASA's ASTER Global Digital Elevation Map, made available by the Jet Propulsion Laboratory, which EA used to create 28 real-life mountains from 9 different ranges for its award-winning game.

  15. On Realistically Attacking Tor with Website Fingerprinting

    Directory of Open Access Journals (Sweden)

    Wang Tao

    2016-10-01

    Full Text Available Website fingerprinting allows a local, passive observer monitoring a web-browsing client’s encrypted channel to determine her web activity. Previous attacks have shown that website fingerprinting could be a threat to anonymity networks such as Tor under laboratory conditions. However, there are significant differences between laboratory conditions and realistic conditions. First, in laboratory tests we collect the training data set together with the testing data set, so the training data set is fresh, but an attacker may not be able to maintain a fresh data set. Second, laboratory packet sequences correspond to a single page each, but for realistic packet sequences the split between pages is not obvious. Third, packet sequences may include background noise from other types of web traffic. These differences adversely affect website fingerprinting under realistic conditions. In this paper, we tackle these three problems to bridge the gap between laboratory and realistic conditions for website fingerprinting. We show that we can maintain a fresh training set with minimal resources. We demonstrate several classification-based techniques that allow us to split full packet sequences effectively into sequences corresponding to a single page each. We describe several new algorithms for tackling background noise. With our techniques, we are able to build the first website fingerprinting system that can operate directly on packet sequences collected in the wild.

  16. Improving Intuition Skills with Realistic Mathematics Education

    Science.gov (United States)

    Hirza, Bonita; Kusumah, Yaya S.; Darhim; Zulkardi

    2014-01-01

    The intention of the present study was to see the improvement of students' intuitive skills. This improvement was seen by comparing the Realistic Mathematics Education (RME)-based instruction with the conventional mathematics instruction. The subject of this study was 164 fifth graders of elementary school in Palembang. The design of this study…

  17. Realistic searches on stretched exponential networks

    Indian Academy of Sciences (India)

    In addition, the linking probability is taken to be dependent on social distances and is governed by a parameter . The searches are realistic in the sense that not all search chains can be completed. An estimate of = ρ/d, where is the success rate and d the dynamic path length, shows that for a network of nodes, ...

  18. Shell model calculation of the nuclear moments of /sup 9/Li in a 2h. omega. space

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.; Meder, M.R.

    1984-10-01

    A recent measurement of the magnitude of quadrupole moment of the ground state of /sup 9/Li, Q( /sup 9/Li), finds that Vertical BarQ(/sup 9/Li)/Q(/sup 7/Li)Vertical Bar = 0.88 +- 0.18. A variety of shell-model calculations, using p-shell wave functions, predict Q(/sup 9/Li)approx. =1.3Q( /sup 7/Li) and yield quadrupole moments whose magnitudes are approximately half the experimental values. Agreement between theory and experiment is improved when effective charges are used, although the results are still not completely satisfactory. A calculation of the wave functions of the low-lying states of /sup 7/Li and /sup 9/Li using a modified version of the Sussex matrix elements in a model space, including all 0h..omega.. and 2h..omega.. excitations, has been performed. The resulting value for Q( /sup 9/Li) was -3.46 fm/sup 2/ as ray transitions in /sup 52,53/Cr and /sup 54,55/Mn have been observed using /sup 7/Li(/sup 51/V,xn yp z..cap alpha.. ..gamma..) fusion-evaporation reactions and ..gamma..-particle coincidence techniques. The experiment involved the same reaction at the same center-of-mass energy as the earlier work of Poletti et al., but with target and projectile interchanged. In the present work, eight additional transitions have been identified as occurring in /sup 52/Cr. This provides corroboration of results obtained more recently via /sup 50/Ti(..cap alpha..,2n..gamma..)/sup 52/Cr reaction studies. A simple, efficient approach to the spectroscopy of weakly populated nuclear states which provides for unambiguous isotopic assignments is thus demonstrated.

  19. IMMERSE: Interactive Mentoring for Multimodal Experiences in Realistic Social Encounters

    Science.gov (United States)

    2015-08-28

    perhaps because he’s a mafia member with some inside dirt on the Mayor or something similar. With those intuitions in mind, we will now try to provide...to reinterpret their roles, seeking some way to make sense of the corporal’s behaviors. Perhaps, for example, he is secretly a mafia member with a

  20. Exposure Render: An Interactive Photo-Realistic Volume Rendering Framework

    National Research Council Canada - National Science Library

    Kroes, T; Post, F.H; Botha, C.P

    2012-01-01

    The field of volume visualization has undergone rapid development during the past years, both due to advances in suitable computing hardware and due to the increasing availability of large volume datasets...

  1. Shell model with several particles in the continuum: application to the two-proton decay; Modele en couches avec plusieurs particules dans le continuum: description de la radioactivite deux protons

    Energy Technology Data Exchange (ETDEWEB)

    Rotureau, J

    2005-02-15

    The recent experimental results concerning nuclei at the limit of stability close to the drip-lines and in particular the two-proton emitters require a development of new methodologies to reliably calculate and understand properties of those exotic physical systems. In this work we have extended the Shell Model Embedded in the Continuum (SMEC) in order to describe the coupling with two particles in the scattering continuum. We have obtained a microscopic description of the two-proton emission that takes into account the antisymmetrization of the total wavefunction, the configuration mixing and the three-body asymptotics. We have studied the decay of the 1{sub 2}{sup -} state in {sup 18}Ne in two limiting cases: (i) a sequential emission of two protons through the correlated continuum of {sup 17}F and (ii) emission of {sup 2}He cluster that disintegrates because of the final state interaction (diproton emission). Independently of the choice of the effective interaction we have observed that the two-proton emission of the 1{sub 2}{sup -} in {sup 18}Ne is mainly a sequential process; the ratio between the widths of the diproton emission and the sequential decay does not exceed 8% in any case. (author)

  2. REALISTIC CONCEPTION OF V.M. BEHTEREV

    OpenAIRE

    Korobkova S. N.

    2016-01-01

    In the focus of the article we have the philosophical concept of the outstanding scientist and social activist V.M. Behterev, which is considered as philosophical realism. Philosophical realism is a trend of Russian intellectual thought. It aims to study the nature and the man is substantial part of which. In this way, the realism is based on the anthropological tradition. Realistic ideology, which is developed by scientists, indicates the comprehension of the relationship of material and ide...

  3. Research of shot noise based on realistic nano-MOSFETs

    Directory of Open Access Journals (Sweden)

    Xiaofei Jia

    2017-05-01

    Full Text Available Experimental measurements and simulation results have shown that the dominant noise source of current noise changes from thermal noise to shot noise with scaling of MOSFET, and shot noise were suppressed by Fermi and Coulomb interactions. In this paper, Shot noise test system is established, and experimental results proved that shot noise were suppressed, and the expressions of shot noise in realistic nano-MOSFETs are derived with considering Fermi effect, Coulomb interaction and the combination of the both co-existence, respectively. On this basis, the variation of shot noise with voltage, temperature and source-drain doping were researched. The results we obtained are consistent with those from experiments and the theoretically explanation is given. At the same time, the shot noise test system is suitable for traditional nanoscale electronic components; the shot noise model is suitable for nanoscale MOSFET.

  4. LANL* V1.0: a radiation belt drift shell model suitable for real-time and reanalysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Koller, Josep [Los Alamos National Laboratory; Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory

    2008-01-01

    Space weather modeling, forecasts, and predictions, especially for the radiation belts in the inner magnetosphere, require detailed information about the Earth's magnetic field. Results depend on the magnetic field model and the L* (pron. L-star) values which are used to describe particle drift shells. Space wather models require integrating particle motions along trajectories that encircle the Earth. Numerical integration typically takes on the order of 10{sup 5} calls to a magnetic field model which makes the L* calculations very slow, in particular when using a dynamic and more accurate magnetic field model. Researchers currently tend to pick simplistic models over more accurate ones but also risking large inaccuracies and even wrong conclusions. For example, magnetic field models affect the calculation of electron phase space density by applying adiabatic invariants including the drift shell value L*. We present here a new method using a surrogate model based on a neural network technique to replace the time consuming L* calculations made with modern magnetic field models. The advantage of surrogate models (or meta-models) is that they can compute the same output in a fraction of the time while adding only a marginal error. Our drift shell model LANL* (Los Alamos National Lab L-star) is based on L* calculation using the TSK03 model. The surrogate model has currently been tested and validated only for geosynchronous regions but the method is generally applicable to any satellite orbit. Computations with the new model are several million times faster compared to the standard integration method while adding less than 1% error. Currently, real-time applications for forecasting and even nowcasting inner magnetospheric space weather is limited partly due to the long computing time of accurate L* values. Without them, real-time applications are limited in accuracy. Reanalysis application of past conditions in the inner magnetosphere are used to understand

  5. MetAssimulo: simulation of realistic NMR metabolic profiles.

    Science.gov (United States)

    Muncey, Harriet J; Jones, Rebecca; De Iorio, Maria; Ebbels, Timothy M D

    2010-10-06

    Probing the complex fusion of genetic and environmental interactions, metabolic profiling (or metabolomics/metabonomics), the study of small molecules involved in metabolic reactions, is a rapidly expanding 'omics' field. A major technique for capturing metabolite data is 1H-NMR spectroscopy and this yields highly complex profiles that require sophisticated statistical analysis methods. However, experimental data is difficult to control and expensive to obtain. Thus data simulation is a productive route to aid algorithm development. MetAssimulo is a MATLAB-based package that has been developed to simulate 1H-NMR spectra of complex mixtures such as metabolic profiles. Drawing data from a metabolite standard spectral database in conjunction with concentration information input by the user or constructed automatically from the Human Metabolome Database, MetAssimulo is able to create realistic metabolic profiles containing large numbers of metabolites with a range of user-defined properties. Current features include the simulation of two groups ('case' and 'control') specified by means and standard deviations of concentrations for each metabolite. The software enables addition of spectral noise with a realistic autocorrelation structure at user controllable levels. A crucial feature of the algorithm is its ability to simulate both intra- and inter-metabolite correlations, the analysis of which is fundamental to many techniques in the field. Further, MetAssimulo is able to simulate shifts in NMR peak positions that result from matrix effects such as pH differences which are often observed in metabolic NMR spectra and pose serious challenges for statistical algorithms. No other software is currently able to simulate NMR metabolic profiles with such complexity and flexibility. This paper describes the algorithm behind MetAssimulo and demonstrates how it can be used to simulate realistic NMR metabolic profiles with which to develop and test new data analysis techniques

  6. INVITED ARTICLE: Towards dense, realistic granular media in 2D

    Science.gov (United States)

    Luding, Stefan

    2009-12-01

    The development of an applicable theory for granular matter—with both qualitative and quantitative value—is a challenging prospect, given the multitude of states, phases and (industrial) situations it has to cover. Given the general balance equations for mass, momentum and energy, the limiting case of dilute and almost elastic granular gases, where kinetic theory works perfectly well, is the starting point. In most systems, low density co-exists with very high density, where the latter is an open problem for kinetic theory. Furthermore, many additional nonlinear phenomena and material properties are important in realistic granular media, involving, e.g.: (i) multi-particle interactions and elasticity (ii) strong dissipation, (iii) friction, (iv) long-range forces and wet contacts, (v) wide particle size distributions and (vi) various particle shapes. Note that, while some of these issues are more relevant for high density, others are important for both low and high densities; some of them can be dealt with by means of kinetic theory, some cannot. This paper is a review of recent progress towards more realistic models for dense granular media in 2D, even though most of the observations, conclusions and corrections given are qualitatively true also in 3D. Starting from an elastic, frictionless and monodisperse hard sphere gas, the (continuum) balance equations of mass, momentum and energy are given. The equation of state, the (Navier-Stokes level) transport coefficients and the energy-density dissipation rate are considered. Several corrections are applied to those constitutive material laws—one by one—in order to account for the realistic physical effects and properties listed above.

  7. MetAssimulo:Simulation of Realistic NMR Metabolic Profiles

    Directory of Open Access Journals (Sweden)

    De Iorio Maria

    2010-10-01

    Full Text Available Abstract Background Probing the complex fusion of genetic and environmental interactions, metabolic profiling (or metabolomics/metabonomics, the study of small molecules involved in metabolic reactions, is a rapidly expanding 'omics' field. A major technique for capturing metabolite data is 1H-NMR spectroscopy and this yields highly complex profiles that require sophisticated statistical analysis methods. However, experimental data is difficult to control and expensive to obtain. Thus data simulation is a productive route to aid algorithm development. Results MetAssimulo is a MATLAB-based package that has been developed to simulate 1H-NMR spectra of complex mixtures such as metabolic profiles. Drawing data from a metabolite standard spectral database in conjunction with concentration information input by the user or constructed automatically from the Human Metabolome Database, MetAssimulo is able to create realistic metabolic profiles containing large numbers of metabolites with a range of user-defined properties. Current features include the simulation of two groups ('case' and 'control' specified by means and standard deviations of concentrations for each metabolite. The software enables addition of spectral noise with a realistic autocorrelation structure at user controllable levels. A crucial feature of the algorithm is its ability to simulate both intra- and inter-metabolite correlations, the analysis of which is fundamental to many techniques in the field. Further, MetAssimulo is able to simulate shifts in NMR peak positions that result from matrix effects such as pH differences which are often observed in metabolic NMR spectra and pose serious challenges for statistical algorithms. Conclusions No other software is currently able to simulate NMR metabolic profiles with such complexity and flexibility. This paper describes the algorithm behind MetAssimulo and demonstrates how it can be used to simulate realistic NMR metabolic profiles with

  8. Large-system transformation in health care: a realist review.

    Science.gov (United States)

    Best, Allan; Greenhalgh, Trisha; Lewis, Steven; Saul, Jessie E; Carroll, Simon; Bitz, Jennifer

    2012-09-01

    An evidence base that addresses issues of complexity and context is urgently needed for large-system transformation (LST) and health care reform. Fundamental conceptual and methodological challenges also must be addressed. The Saskatchewan Ministry of Health in Canada requested a six-month synthesis project to guide four major policy development and strategy initiatives focused on patient- and family-centered care, primary health care renewal, quality improvement, and surgical wait lists. The aims of the review were to analyze examples of successful and less successful transformation initiatives, to synthesize knowledge of the underlying mechanisms, to clarify the role of government, and to outline options for evaluation. We used realist review, whose working assumption is that a particular intervention triggers particular mechanisms of change. Mechanisms may be more or less effective in producing their intended outcomes, depending on their interaction with various contextual factors. We explain the variations in outcome as the interplay between context and mechanisms. We nested this analytic approach in a macro framing of complex adaptive systems (CAS). Our rapid realist review identified five "simple rules" of LST that were likely to enhance the success of the target initiatives: (1) blend designated leadership with distributed leadership; (2) establish feedback loops; (3) attend to history; (4) engage physicians; and (5) include patients and families. These principles play out differently in different contexts affecting human behavior (and thereby contributing to change) through a wide range of different mechanisms. Realist review methodology can be applied in combination with a complex system lens on published literature to produce a knowledge synthesis that informs a prospective change effort in large-system transformation. A collaborative process engaging both research producers and research users contributes to local applications of universal principles and

  9. MANAJEMEN LABA: PERILAKU MANAJEMEN OPPORTUNISTIC ATAU REALISTIC ?

    Directory of Open Access Journals (Sweden)

    I Nyoman Wijana Asmara Putra

    2011-01-01

    Full Text Available Earnings management is a still attractive issue. It is often associatedwith negative behavior conducted by management for its own interest. In fact,it also has different side to be examined. There is another motivation to do so,such as to improve the company’s operation. This literature study aims toreview management motivation of doing earnings management, whetheropportunistic or realistic. What conflict that earnings management brings,what pro and cons about it, what would happen if earnings is not managed,whether the company would be better off or worse off.

  10. An Introduction to a Realistic Quantum Physics

    CERN Document Server

    Preparata, Giuliano

    2003-01-01

    This book is a remarkable synthesis, a clear and simple introduction to Quantum Physics with a sort of Galilean dialogue on the supreme systems of contemporary Physics. The author, whose research interests and work extended from quarks to liquid systems and from crystals to stars, introduces the common conceptual and mathematical framework of all quantum theories, realistic enough to successfully confront Nature: Quantum Field Theory applied to the study of both dilute and condensed matter. In the dilute limit, quantum mechanics is shown to be a good approximation to Quantum Field Theory. Howe

  11. Cellular automaton for realistic modelling of landslides

    CERN Document Server

    Segrè, E; Enrico Segre; Chiara Deangeli

    1994-01-01

    We develop a numerical model for the simulation of debris flow in landslides over a complex three dimensional topography. The model is based on a lattice, in which debris can be transferred among nearest neighbours according to established empirical relationships for granular flows. The model is validated comparing its results with reported field data. Our model is in fact a realistic elaboration of simpler ``sandpile automata'', which have in recent years been studied as supposedly paradigmatic of ``self organized criticality''. Statistics and scaling properties of the simulation are examined, showing that the model has an intermittent behaviour.

  12. Convective aggregation in realistic convective-scale simulations

    Science.gov (United States)

    Holloway, Christopher E.

    2017-06-01

    To investigate the real-world relevance of idealized-model convective self-aggregation, five 15 day cases of real organized convection in the tropics are simulated. These include multiple simulations of each case to test sensitivities of the convective organization and mean states to interactive radiation, interactive surface fluxes, and evaporation of rain. These simulations are compared to self-aggregation seen in the same model configured to run in idealized radiative-convective equilibrium. Analysis of the budget of the spatial variance of column-integrated frozen moist static energy shows that control runs have significant positive contributions to organization from radiation and negative contributions from surface fluxes and transport, similar to idealized runs once they become aggregated. Despite identical lateral boundary conditions for all experiments in each case, systematic differences in mean column water vapor (CWV), CWV distribution shape, and CWV autocorrelation length scale are found between the different sensitivity runs, particularly for those without interactive radiation, showing that there are at least some similarities in sensitivities to these feedbacks in both idealized and realistic simulations (although the organization of precipitation shows less sensitivity to interactive radiation). The magnitudes and signs of these systematic differences are consistent with a rough equilibrium between (1) equalization due to advection from the lateral boundaries and (2) disaggregation due to the absence of interactive radiation, implying disaggregation rates comparable to those in idealized runs with aggregated initial conditions and noninteractive radiation. This points to a plausible similarity in the way that radiation feedbacks maintain aggregated convection in both idealized simulations and the real world.Plain Language SummaryUnderstanding the processes that lead to the organization of tropical rainstorms is an important challenge for weather

  13. Observation and empirical shell-model study of new yrast excited states in the nucleus sup 1 sup 4 sup 2 Ce

    CERN Document Server

    Liu Zhong; Guo Ying Xiang; Zhou Xiao Hong; Lei Xiang Guo; LiuMinLiang; Luo Wan Ju; He Jian Jun; Zheng Yong; Pan Qiang Yan; Gan Zai Guo; Luo Yi Xiao; Hayakawa, T; Oshima, M; Toh, Y; Shizima, T; Hatsukawa, Y; Osa, A; Ishii, T; Sugawara, M

    2002-01-01

    Excited states of sup 1 sup 4 sup 2 Ce, populated in deep inelastic reactions of sup 8 sup 2 Se projectiles bombarding sup 1 sup 3 sup 9 La target, have been studied to medium spins using in-beam gamma spectroscopy techniques. Three new levels have been identified at 2625, 2995 and 3834 keV, and assigned as 8 sup + , 9 sup ( sup - sup ) and 11 sup ( sup - sup ) , respectively, based on the analysis of the properties of gamma transitions. These new yrast states follow well the level systematics of N 84 isotones. Their structures have been discussed with the help of empirical shell-model calculations

  14. Realistic theory of electronic correlations in nanoscopic systems

    Science.gov (United States)

    Schüler, Malte; Barthel, Stefan; Wehling, Tim; Karolak, Michael; Valli, Angelo; Sangiovanni, Giorgio

    2017-07-01

    Nanostructures with open shell transition metal or molecular constituents host often strong electronic correlations and are highly sensitive to atomistic material details. This tutorial review discusses method developments and applications of theoretical approaches for the realistic description of the electronic and magnetic properties of nanostructures with correlated electrons. First, the implementation of a flexible interface between density functional theory and a variant of dynamical mean field theory (DMFT) highly suitable for the simulation of complex correlated structures is explained and illustrated. On the DMFT side, this interface is largely based on recent developments of quantum Monte Carlo and exact diagonalization techniques allowing for efficient descriptions of general four fermion Coulomb interactions, reduced symmetries and spin-orbit coupling, which are explained here. With the examples of the Cr (001) surfaces, magnetic adatoms, and molecular systems it is shown how the interplay of Hubbard U and Hund's J determines charge and spin fluctuations and how these interactions drive different sorts of correlation effects in nanosystems. Non-local interactions and correlations present a particular challenge for the theory of low dimensional systems. We present our method developments addressing these two challenges, i.e., advancements of the dynamical vertex approximation and a combination of the constrained random phase approximation with continuum medium theories. We demonstrate how non-local interaction and correlation phenomena are controlled not only by dimensionality but also by coupling to the environment which is typically important for determining the physics of nanosystems.

  15. Principles of maximally classical and maximally realistic quantum ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 59; Issue 2. Principles of maximally classical and maximally realistic quantum mechanics. S M Roy. Volume 59 Issue 2 August ... Keywords. Maximally realistic quantum theory; phase space Bell inequalities; maximally classical trajectories in realistic quantum theory.

  16. Developing Scene Understanding Neural Software for Realistic Autonomous Outdoor Missions

    Science.gov (United States)

    2017-09-01

    salient objects and environments providing mutual context (i.e., a primary or key object in an outdoor scene embedded in a realistic environmental ...tracking: a two part vision system for small robot navigation in forested environment . Proc. SPIE 8387, Unmanned Systems Technology XIV Conference; 2012...of realistic autonomous outdoor missions in complex and changing environments . Scene understanding for realistic outdoor missions has been

  17. Transforming the patient care environment with Lean Six Sigma and realistic evaluation.

    Science.gov (United States)

    Black, Jason

    2009-01-01

    Lean Six Sigma (LSS) is a structured methodology for transforming processes, but it does not fully consider the complex social interactions that cause processes to form in hospital organizations. By combining LSS implementations with the concept of Realistic Evaluation, a methodology that promotes change by assessing and considering the individual characteristics of an organization's social environment, successful and sustainable process improvement is more likely.

  18. Polygonal plate modeling of realistic structures

    Science.gov (United States)

    Newman, E. H.; Alexandropoulos, P.; Walton, E. K.

    1984-07-01

    The effectiveness of method of moments (MM) surface patch modeling for describing realistic structures is demonstrated, as is a technique for analyzing the intersection of several plates or patches. Surface patch MM models consider perfectly conducting surfaces, thus allowing computerized studies of hundreds of modes in terms of a small number of plates. An electric field formulation applicable to both closed and open surfaces is employed with a scale model or drawing of an aircraft structure. Plates intersecting along edges involve continuity of the normal component of current at the juncture. Overlap modes are defined that permit current to flow from one plate to another but do not permit linear dependencies between the modes. Examples are given for radar cross sections of the 747, the Concorde and a rocket and verified with reference to an available data base.

  19. Realistic page-turning of electronic books

    Science.gov (United States)

    Fan, Chaoran; Li, Haisheng; Bai, Yannan

    2014-01-01

    The booming electronic books (e-books), as an extension to the paper book, are popular with readers. Recently, many efforts are put into the realistic page-turning simulation o f e-book to improve its reading experience. This paper presents a new 3D page-turning simulation approach, which employs piecewise time-dependent cylindrical surfaces to describe the turning page and constructs smooth transition method between time-dependent cylinders. The page-turning animation is produced by sequentially mapping the turning page into the cylinders with different radii and positions. Compared to the previous approaches, our method is able to imitate various effects efficiently and obtains more natural animation of turning page.

  20. Realistic Simulations of Coronagraphic Observations with WFIRST

    Science.gov (United States)

    Rizzo, Maxime; Zimmerman, Neil; Roberge, Aki; Lincowski, Andrew; Arney, Giada; Stark, Chris; Jansen, Tiffany; Turnbull, Margaret; WFIRST Science Investigation Team (Turnbull)

    2018-01-01

    We present a framework to simulate observing scenarios with the WFIRST Coronagraphic Instrument (CGI). The Coronagraph and Rapid Imaging Spectrograph in Python (crispy) is an open-source package that can be used to create CGI data products for analysis and development of post-processing routines. The software convolves time-varying coronagraphic PSFs with realistic astrophysical scenes which contain a planetary architecture, a consistent dust structure, and a background field composed of stars and galaxies. The focal plane can be read out by a WFIRST electron-multiplying CCD model directly, or passed through a WFIRST integral field spectrograph model first. Several elementary post-processing routines are provided as part of the package.

  1. E. H. Carr: En kompleks realist

    DEFF Research Database (Denmark)

    Meyn, Carina Ann

    2008-01-01

    Edward Hallett Carr er blevet kaldt alt fra realist til utopist til slet og ret ,,farlig". Denne artikel giver en bedre forstaelse af, hvorfor et centralt pejlemærke i disci­plinen international politik bliver beskrevet på så mange - tilsyneladende - modsætningsfyldte måder. I stedet for at tage...... udgangspunkt i en realistisk eller en utopisk læsning af Carrs værker bidrager denne artikel med en tredje læsning af Carrs teori, der samtænker ,,den realistiske Carr" og ,,den utopiske Carr". Det overordnede argument i artiklen er, at for at kunne finde mening og sammen­hæng i Carrs politiske teori, ma man...... nødvendigvis samtænke Carrs realisme og utopisme med hans underliggende radikalisme....

  2. Comparing Realistic Subthalamic Nucleus Neuron Models

    Science.gov (United States)

    Njap, Felix; Claussen, Jens C.; Moser, Andreas; Hofmann, Ulrich G.

    2011-06-01

    The mechanism of action of clinically effective electrical high frequency stimulation is still under debate. However, recent evidence points at the specific activation of GABA-ergic ion channels. Using a computational approach, we analyze temporal properties of the spike trains emitted by biologically realistic neurons of the subthalamic nucleus (STN) as a function of GABA-ergic synaptic input conductances. Our contribution is based on a model proposed by Rubin and Terman and exhibits a wide variety of different firing patterns, silent, low spiking, moderate spiking and intense spiking activity. We observed that most of the cells in our network turn to silent mode when we increase the GABAA input conductance above the threshold of 3.75 mS/cm2. On the other hand, insignificant changes in firing activity are observed when the input conductance is low or close to zero. We thus reproduce Rubin's model with vanishing synaptic conductances. To quantitatively compare spike trains from the original model with the modified model at different conductance levels, we apply four different (dis)similarity measures between them. We observe that Mahalanobis distance, Victor-Purpura metric, and Interspike Interval distribution are sensitive to different firing regimes, whereas Mutual Information seems undiscriminative for these functional changes.

  3. Differentiability of correlations in realistic quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, Alejandro [Instituto de Matemática, UFRJ, CEP 21941-909 Rio de Janeiro, Rio de Janeiro (Brazil); Faria, Edson de [Instituto de Matemática e Estatística, USP, Rua do Matão 1010, SP 05508-090 São Paulo, São Paulo (Brazil); Pujals, Enrique [IMPA, Estrada Dona Castorina 110, 22460-320 Rio de Janeiro, Rio de Janeiro (Brazil); Tresser, Charles [IBM, P.O. Box 218, Yorktown Heights, New York 10598 (United States)

    2015-09-15

    We prove a version of Bell’s theorem in which the locality assumption is weakened. We start by assuming theoretical quantum mechanics and weak forms of relativistic causality and of realism (essentially the fact that observable values are well defined independently of whether or not they are measured). Under these hypotheses, we show that only one of the correlation functions that can be formulated in the framework of the usual Bell theorem is unknown. We prove that this unknown function must be differentiable at certain angular configuration points that include the origin. We also prove that, if this correlation is assumed to be twice differentiable at the origin, then we arrive at a version of Bell’s theorem. On the one hand, we are showing that any realistic theory of quantum mechanics which incorporates the kinematic aspects of relativity must lead to this type of rough correlation function that is once but not twice differentiable. On the other hand, this study brings us a single degree of differentiability away from a relativistic von Neumann no hidden variables theorem.

  4. Lean thinking in healthcare: a realist review of the literature.

    Science.gov (United States)

    Mazzocato, Pamela; Savage, Carl; Brommels, Mats; Aronsson, Håkan; Thor, Johan

    2010-10-01

    To understand how lean thinking has been put into practice in healthcare and how it has worked. A realist literature review. Data sources The authors systematically searched for articles in PubMed, Web of Science and Business Source Premier (January 1998 to February 2008) and then added articles through a snowball approach. The authors included empirical studies of lean thinking applications in healthcare and excluded those articles that did not influence patient care, or reported hybrid approaches. The authors conducted a thematic analysis based on data collected using an original abstraction form. Based on this, they articulated interactions between context, lean interventions, mechanisms and outcomes. The authors reviewed 33 articles and found a wide range of lean applications. The articles describe initial implementation stages and emphasise technical aspects. All articles report positive results. The authors found common contextual aspects which interact with different components of the lean interventions and trigger four different change mechanisms: understand processes to generate shared understanding; organise and design for effectiveness and efficiency; improve error detection to increase awareness and process reliability; and collaborate to systematically solve problems to enhance continual improvement. Lean thinking has been applied successfully in a wide variety of healthcare settings. While lean theory emphasises a holistic view, most cases report narrower technical applications with limited organisational reach. To better realise the potential benefits, healthcare organisations need to directly involve senior management, work across functional divides, pursue value creation for patients and other customers, and nurture a long-term view of continual improvement.

  5. Investigation of the structure of core-coupled odd-proton copper nuclei in fpg valence space using the projected shell model

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Anuradha; Singh, Suram; Bharti, Arun [University of Jammu, Department of Physics and Electronics, Jammu (India); Khosa, S.K. [Central University of Jammu, Department of Physics and Astronomical Sciences, Jammu (India); Bhat, G.H.; Sheikh, J.A. [University of Kashmir, Department of Physics, Srinagar (India)

    2017-01-15

    By employing a systematically parametrized Hamiltonian and the best fit of the various input parameters, high-spin yrast energy states for an isotopic chain of odd mass {sup 59-69}Cu nuclei have been investigated by using a novel computational quantum mechanical framework-projected shell model. Comparison of calculations and experiments yields good agreement. The present study of various intriguing nuclear structure properties along the yrast lines in these odd proton isotopes reflects some interesting informative nuclear physics results. The calculations successfully describe the formation of the yrast level structures from multi-quasi-particle configurations based on πf x νg bands for {sup 59-69}Cu isotopes. The present calculations indicate the evolution of the nuclear structure near the magic nuclei, Ni, and also provide an indication of coexistence of both, collective as well as single-particle, levels for {sup 69}Cu nucleus at N=40. (orig.)

  6. Strongly screening electron capture for nuclides 52, 53, 59, 60Fe by the Shell-Model Monte Carlo method in pre-supernovae

    Science.gov (United States)

    Liu, Jing-Jing; Peng, Qiu-He; Liu, Dong-Mei

    2017-09-01

    The death of massive stars due to supernova explosions is a key ingredient in stellar evolution and stellar population synthesis. Electron capture (EC) plays a vital role in supernova explosions. Using the Shell-Model Monte Carlo method, based on the nuclear random phase approximation and linear response theory model for electrons, we study the strong screening EC rates of 52, 53, 59, 60Fe in pre-supernovae. The results show that the screening rates can decrease by about 18.66%. Our results may become a good foundation for future investigation of the evolution of late-type stars, supernova explosion mechanisms and numerical simulations. Supported by National Natural Science Foundation of China (11565020), Counterpart Foundation of Sanya (2016PT43), Special Foundation of Science and Technology Cooperation for Advanced Academy and Regional of Sanya (2016YD28), Scientific Research Staring Foundation for 515 Talented Project of Hainan Tropical Ocean University (RHDRC201701) and Natural Science Foundation of Hainan Province (114012)

  7. Shell-model calculations for the semi-magic nucleus 85Br and systematic features of the N = 50 odd-A isotones

    Science.gov (United States)

    Guo, Rui-Ju; Li, Zhi-Quan; Liu, Chen; Tian, Yong-He; Wang, Shou-Yu

    2017-08-01

    Level structures of 85Br have been investigated using the shell-model code nushellx within a large model space containing the neutron-core excitations across the N = 50 closed shell. The calculated results have been compared with the available experimental data. Reasonable agreement between the experimental and calculated values is obtained, which indicates that the neutron-core excitations are essential to reproduce the level structures of 85Br. The systematic features of neutron-core excitations in the N = 50 isotones are investigated. Supported by Natural Science Foundation of China (11622540, 11461141001, U1432119) and Computations were Carried Out on an HP Proliant DL785G6 Server Hosted by the Institute of Space Science of Shandong University

  8. Chinese Infrastructure in South Asia: A Realist and Liberal Perspective

    Science.gov (United States)

    2015-12-01

    Defining the Realist and Liberal Lenses Realist theorists see the world as an anarchical state of affairs in which states vie for power under the...Defensive realists like Kenneth Waltz concur that the anarchical world is a power struggle among self-interested states, but argue that states do not...Phase Zero Operations” and “road diplomacy,” which will be addressed in following chapters. Where realism defines the world as an anarchical power grab

  9. On the realistic validation of photometric redshifts

    Science.gov (United States)

    Beck, R.; Lin, C.-A.; Ishida, E. E. O.; Gieseke, F.; de Souza, R. S.; Costa-Duarte, M. V.; Hattab, M. W.; Krone-Martins, A.

    2017-07-01

    Two of the main problems encountered in the development and accurate validation of photometric redshift (photo-z) techniques are the lack of spectroscopic coverage in the feature space (e.g. colours and magnitudes) and the mismatch between the photometric error distributions associated with the spectroscopic and photometric samples. Although these issues are well known, there is currently no standard benchmark allowing a quantitative analysis of their impact on the final photo-z estimation. In this work, we present two galaxy catalogues, Teddy and Happy, built to enable a more demanding and realistic test of photo-z methods. Using photometry from the Sloan Digital Sky Survey and spectroscopy from a collection of sources, we constructed data sets that mimic the biases between the underlying probability distribution of the real spectroscopic and photometric sample. We demonstrate the potential of these catalogues by submitting them to the scrutiny of different photo-z methods, including machine learning (ML) and template fitting approaches. Beyond the expected bad results from most ML algorithms for cases with missing coverage in the feature space, we were able to recognize the superiority of global models in the same situation and the general failure across all types of methods when incomplete coverage is convoluted with the presence of photometric errors - a data situation which photo-z methods were not trained to deal with up to now and which must be addressed by future large-scale surveys. Our catalogues represent the first controlled environment allowing a straightforward implementation of such tests. The data are publicly available within the COINtoolbox (https://github.com/COINtoolbox/photoz_catalogues).

  10. A realistic approach to locating dental practices.

    Science.gov (United States)

    Barron, E G; Shirley, W L; Waldrep, A C

    1984-12-01

    A realistic approach to locating a dental practice involves the consideration of factors affecting the demand for dental services in an area. This dictates examination of the demographic and economic determinants of demand. Many retail businesses have used this approach to making locational decisions, and dentistry should benefit from this same process. If the thesis is accepted that dentistry is a business as well as a profession, it follows that the dentist-business person must be permitted, indeed expected, to make a reasonable return in revenue on the investment of dollars in education, equipment, and other related expenses. This return on investment occurs only when there is adequate patient flow. An objective procedure to assess demand for dental services at a particular location has been described. With this method, students were expected to: Visit the community and, through interviews with other professionals and knowledgeable business persons, determine the extent of the probable dental service area. The service area is circumscribed on a census map. Use the census subdivision numbers on the map to secure data from the state data center that describes the area's population, in regard to age, race, gender, income, and education. Transfer the data to a spreadsheet designed to generate total visits, according to each of the demand determinants. Calculate the number of FTE practitioners needed to meet this potential demand, and compare this with the number of FTE dentists presently practicing in the community. Fourteen senior dental students, who have since graduated, have completed this procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. LANL* V1.0: a radiation belt drift shell model suitable for real-time and reanalysis applications

    Directory of Open Access Journals (Sweden)

    J. Koller

    2009-07-01

    Full Text Available We describe here a new method for calculating the magnetic drift invariant, L*, that is used for modeling radiation belt dynamics and for other space weather applications. L* (pronounced L-star is directly proportional to the integral of the magnetic flux contained within the surface defined by a charged particle moving in the Earth's geomagnetic field. Under adiabatic changes to the geomagnetic field L* is a conserved quantity, while under quasi-adiabatic fluctuations diffusion (with respect to a particle's L* is the primary term in equations of particle dynamics. In particular the equations of motion for the very energetic particles that populate the Earth's radiation belts are most commonly expressed by diffusion in three dimensions: L*, energy (or momentum, and pitch angle (the dot product of velocity and the magnetic field vector. Expressing dynamics in these coordinates reduces the dimensionality of the problem by referencing the particle distribution functions to values at the magnetic equatorial point of a magnetic "drift shell" (or L-shell irrespective of local time (or longitude. While the use of L* aids in simplifying the equations of motion, practical applications such as space weather forecasting using realistic geomagnetic fields require sophisticated magnetic field models that, in turn, require computationally intensive numerical integration. Typically a single L* calculation can require on the order of 105 calls to a magnetic field model and each point in the simulation domain and each calculated pitch angle has a different value of L*. We describe here the development and validation of a neural network surrogate model for calculating L* in sophisticated geomagnetic field models with a high degree of fidelity at computational speeds that are millions of times faster than direct numerical field line mapping and integration. This new surrogate model has

  12. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested...... including puppetry and dance. However, the aesthetics of these traditions vary across cultures and carry different associative and interpretive meanings. Puppetry offers a useful frame for understanding the relationship between abstract and imitative gestures and behavior, and instantiates the complex...

  13. Creating Realistic Virtual Textures from Contact Acceleration Data.

    Science.gov (United States)

    Romano, J M; Kuchenbecker, K J

    2012-01-01

    Modern haptic interfaces are adept at conveying the large-scale shape of virtual objects, but they often provide unrealistic or no feedback when it comes to the microscopic details of surface texture. Direct texture-rendering challenges the state of the art in haptics because it requires a finely detailed model of the surface's properties, real-time dynamic simulation of complex interactions, and high-bandwidth haptic output to enable the user to feel the resulting contacts. This paper presents a new, fully realized solution for creating realistic virtual textures. Our system employs a sensorized handheld tool to capture the feel of a given texture, recording three-dimensional tool acceleration, tool position, and contact force over time. We reduce the three-dimensional acceleration signals to a perceptually equivalent one-dimensional signal, and then we use linear predictive coding to distill this raw haptic information into a database of frequency-domain texture models. Finally, we render these texture models in real time on a Wacom tablet using a stylus augmented with small voice coil actuators. The resulting virtual textures provide a compelling simulation of contact with the real surfaces, which we verify through a human subject study.

  14. Realistic Matematic Approach through Numbered Head Together Learning Model

    Science.gov (United States)

    Sugihatno, A. C. M. S.; Budiyono; Slamet, I.

    2017-09-01

    Recently, the teaching process which is conducted based on teacher center affect the students interaction in the class. It causes students become less interest to participate. That is why teachers should be more creative in designing learning using other types of cooperative learning model. Therefore, this research is aimed to implement NHT with RMA in the teaching process. We utilize NHT since it is a variant of group discussion whose aim is giving a chance to the students to share their ideas related to the teacher’s question. By using NHT in the class, a teacher can give a better understanding about the material which is given with the help of Realistic Mathematics Approach (RMA) which known for its real problem contex. Meanwhile, the researcher assumes instead of selecting teaching model, Adversity Quotient (AQ) of student also influences students’ achievement. This research used the quasi experimental research. The samples is 60 students in junior high school, it was taken by using the stratified cluster random sampling technique. The results show NHT-RMA gives a better learning achievement of mathematics than direct teaching model and NHT-RMA teaching model with categorized as high AQ show different learning achievement from the students with categorized as moderate and low AQ.

  15. Realistic Quantum Control of Energy Transfer in Photosynthetic Processes

    Directory of Open Access Journals (Sweden)

    Reda M. El-Shishtawy

    2016-12-01

    Full Text Available The occurrence of coherence phenomenon as a result of the interference of the probability amplitude terms is among the principle features of quantum mechanics concepts. Current experiments display the presence of quantum techniques whose coherence is supplied over large interval times. Specifically, photosynthetic mechanisms in light-harvesting complexes furnish oscillatory behaviors owing to quantum coherence. In this manuscript, we study the coherent quantum energy transfer for a single-excitation and nonlocal correlation in a dimer system (donor+acceptor displayed by two-level systems (TLSs, interacting with a cavity field with a time-dependent coupling effect considering the realistic situation of coupling between each TLS and the cavity field. We analyze and explore the specific conditions which are viable with real experimental realization for the ultimate transfer of quantum energy and nonlocal quantum correlation. We show that the enhancement of the probability for a single-excitation energy transfer greatly benefits from the energy detuning, photon-number transition, classicality of the field, and the time-dependent coupling effect. We also find that the entanglement between the donor and acceptor is very sensitive to the physical parameters and it can be generated during the coherent energy transfer.

  16. Self-consistent calculations in spherical metal clusters with uniformly averaged realistic pseudopotentials

    Energy Technology Data Exchange (ETDEWEB)

    Alasia, F. [Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Serra, L. [Departament de Fisica, Universitat de les Illes Balears, E-07071 Palma de Mallorca (Spain); Broglia, R.A. [Dipartimento di Fisica, Universita di Milano, Via Celoria 16, I-20133 Milano (Italy)]|[Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, I-20133 Milano (Italy)]|[The Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Van Giai, N. [Division de Physique Theorique, Institut de Physique Nucleaire, F-91406 Orsay Cedex (France); Lipparini, E. [Dipartimento di Fisica, Universita degli Studi di Trento, Trento, I-38050 Povo Trento (Italy)]|[Gruppo Collegato, Istituto Nationale di Fisica Nucleare, Trento I-38050 Povo Trento (Italy); Roman, H.E. [Institut fur Theoretische Physik, Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

    1995-09-15

    Using realistic nonlocal pseudopotentials to describe ion-valence electron interaction, we perform self-consistent calculations of ground and excited states of spherical alkali-metal clusters within the local-density approximation. The ion pseudopotential is uniformly averaged in the cluster sphere within the proposed pseudopotential jellium model. It is found that in small clusters, pseudopotentials lead to predictions that strongly improve those of the jellium model and are very close to the results found previously with pseudo-Hamiltonians.

  17. Self-consistent calculations in spherical metal clusters with uniformly averaged realistic pseudopotentials

    Science.gov (United States)

    Alasia, F.; Serra, Ll.; Broglia, R. A.; van Giai, Nguyen; Lipparini, E.; Roman, H. E.

    1995-09-01

    Using realistic nonlocal pseudopotentials to describe ion-valence electron interaction, we perform self-consistent calculations of ground and excited states of spherical alkali-metal clusters within the local-density approximation. The ion pseudopotential is uniformly averaged in the cluster sphere within the proposed pseudopotential jellium model. It is found that in small clusters, pseudopotentials lead to predictions that strongly improve those of the jellium model and are very close to the results found previously with pseudo-Hamiltonians.

  18. “Each is in different circumstances anyway”: A realist multilevel situational analysis of maternal depression

    OpenAIRE

    Eastwood, John Graeme; Kemp, Lynn Ann; Jalaludin, Bin Badrudin

    2017-01-01

    Introduction: We present here the findings of a realist multilevel situational analysis of maternal depression.  We use situational analysis to identify the interaction of mothers with social structures and the possible causal influence of those social structures on her wellbeing.  The analysis moves from an emergent empirical approach toward the more reflexive and abductive approach of situational analysis thus better informing our abductive reasoning and the generation of theory.  The purpo...

  19. Nuclear structure with unitarily transformed two-body plus phenomenological three-body interactions

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Anneke

    2011-02-02

    The importance of three-nucleon forces for a variety of nuclear structure phenomena is apparent in various investigations. This thesis provides a first step towards the inclusion of realistic three-nucleon forces by studying simple phenomenological threebody interactions. The Unitary Correlation Operator Method (UCOM) and the Similarity Renormalization Group (SRG) provide two different approaches to derive soft phase-shift equivalent nucleon-nucleon (NN) interactions via unitary transformations. Although their motivations are quite different the NN interactions obtained with the two methods exhibit some similarities. The application of the UCOM- or SRG-transformed Argonne V18 potential in the Hartree-Fock (HF) approximation and including the second-order energy corrections emerging from many-body perturbation theory (MBPT) reveals that the systematics of experimental ground-state energies can be reproduced by some of the interactions considering a series of closed-shell nuclei across the whole nuclear chart. However, charge radii are systematically underestimated, especially for intermediate and heavy nuclei. This discrepancy to experimental data is expected to result from neglected three-nucleon interactions. As first ansatz for a three-nucleon force, we consider a finite-range three-body interaction of Gaussian shape. Its influence on ground-state energies and charge radii is discussed in detail on the basis of HF plus MBPT calculations and shows a significant improvement in the description of experimental data. As the handling of the Gaussian three-body interaction is time-extensive, we show that it can be replaced by a regularized three-body contact interaction exhibiting a very similar behavior. An extensive study characterizes its properties in detail and confirms the improvements with respect to nuclear properties. To take into account information of an exact numerical solution of the nuclear eigenvalue problem, the No-Core Shell Model is applied to

  20. Realist Stronghold in the Land of Thucydides? - Appraising and Resisting a Realist Tradition in Greece

    Directory of Open Access Journals (Sweden)

    Kyriakos Mikelis

    2015-10-01

    Full Text Available Given the integration of the discipline of International Relations in Greece into the global discipline since a few decades, the article addresses the reflection of the ‘realism in and for the globe’ question to this specific case. Although the argument doesn’t go as far as to ‘recover’ forgotten IR theorists or self-proclaimed realists, a geopolitical dimension of socio-economic thought during interwar addressed concerns which could be related to the intricacies of realpolitik. Then again at current times, certain scholars have been eager to maintain a firm stance in favor of realism, focusing on the work of ancient figures, especially Thucydides or Homer, and on questions of the offensive-defensive realism debate as well as on the connection with the English School, while others have offered fruitful insights matching the broad constructivist agenda. Overall, certain genuine arguments have appeared, reflecting diversified views about sovereignty and its function or mitigation.

  1. Algebraic tools for dealing with the atomic shell model. I. Wavefunctions and integrals for hydrogen-like ions

    Science.gov (United States)

    Surzhykov, Andrey; Koval, Peter; Fritzsche, Stephan

    2005-01-01

    Today, the 'hydrogen atom model' is known to play its role not only in teaching the basic elements of quantum mechanics but also for building up effective theories in atomic and molecular physics, quantum optics, plasma physics, or even in the design of semiconductor devices. Therefore, the analytical as well as numerical solutions of the hydrogen-like ions are frequently required both, for analyzing experimental data and for carrying out quite advanced theoretical studies. In order to support a fast and consistent access to these (Coulomb-field) solutions, here we present the DIRAC program which has been developed originally for studying the properties and dynamical behavior of the (hydrogen-like) ions. In the present version, a set of MAPLE procedures is provided for the Coulomb wave and Green's functions by applying the (wave) equations from both, the nonrelativistic and relativistic theory. Apart from the interactive access to these functions, moreover, a number of radial integrals are also implemented in the DIRAC program which may help the user to construct transition amplitudes and cross sections as they occur frequently in the theory of ion-atom and ion-photon collisions. Program summaryTitle of program:DIRAC Catalogue number: ADUQ Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADUQ Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: None Computer for which the program is designed and has been tested: All computers with a license of the computer algebra package MAPLE [1] Program language used: Maple 8 and 9 No. of lines in distributed program, including test data, etc.:2186 No. of bytes in distributed program, including test data, etc.: 162 591 Distribution format: tar gzip file CPC Program Library subprograms required: None Nature of the physical problem: Analytical solutions of the hydrogen atom are widely used in very different fields of physics [2,3]. Despite of the rather simple structure

  2. DENSJT: statistical shell-model level density computer code description and user's manual. [In FORTRAN for CDC Cyber-70 computer

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, B.

    1976-07-01

    The FORTRAN code DENSJT described here is constructed to calculate the appropriate moments and dimensions needed in describing the Gaussian level density for fixed values of the total angular momentum (J) and isobaric spin (T = T/sub 0/). The input for this code is the same as in the usual shell-model codes, namely, the single-particle orbital properties and the antisymmetric two-body matrix elements. To calculate the moments for fixed values of the angular momentum (J) a method described by Ginocchio is used. All of the ''basic inputs'' needed in the reduction formula were derived without any restrictions on the orbitals. The formulas used in DENSJT are described, and the basic inputs are listed in tables. A block flow chart showing the general structure and the specific function of each subroutine is included. All necessary information for the input and output of this code is described. A calculation involving 3 orbitals in the s--d shell took 1 second on a CDC Cyber-70 computer. (RWR)

  3. Photo-Realistic Image Synthesis and Virtual Cinematography

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    Realistic Virtual View Synthesis is a new field of research that has received increasing attention in recent years. It is strictly related to the grown popularity of virtual reality and the spread of its applications, among which virtual photography and cinematography. The use of computer generated....... Interestingly, film directors have been looking at the recent progress achieved by the research community in the field of realistic visualization of virtual views, and they have successfully implemented state of the art research approaches in their productions. An innovative concept is then gaining consensus......: the augmented actor. Fundamental concepts and examples of methods proposed for realistic view synthesis based on the transfer of photo-realism from reference photographs to novel views, will be presented. The application of methods for realistic image synthesis to virtual cinematography will also be illustrated...

  4. ImpastoR: a realistic surface display system

    National Research Council Canada - National Science Library

    Ferwerda, James A

    2015-01-01

    .... Our system, based on a desktop PC with GPU hardware, LCD display, light and position sensors, and custom graphics software, supports the photometrically accurate and visually realistic real-time...

  5. Method for generating realistic 3-dimensional models of neuronal cells

    OpenAIRE

    Mata Fernández, Susana; Brito Menéndez, Juan Pedro; Bayona Beriso, Sofía; Pastor Pérez, Luis; Benavides-Piccione, Ruth; Felipe, Javier de

    2014-01-01

    [EN] The present invention relates to a method for the generation of 3-dimensional models of neuronal cells based on incomplete morphological information extracted by means of standard sampling methods. The models generated include a realistic soma, dendritic and axonal trees and dendritic spines, which may be generated at different resolution levels. The invention proposes an innovative technique that makes it possible to obtain a realistic soma form based on a simple definition thereof (suc...

  6. Realist evaluation of an enhanced health visiting programme.

    Science.gov (United States)

    Doi, Lawrence; Jepson, Ruth; Hardie, Samantha

    2017-01-01

    The health visitors' role in many countries is changing. In Scotland, the role has undergone substantial changes through the introduction of an enhanced health visiting programme, which includes increased, structured home visits. This evaluation was conducted within NHS Ayrshire and Arran, one of the 14 Scottish Health Boards. Our aim was to understand and explain how, and why, the programme could contribute to improving health and wellbeing outcomes for children and families. We used a realist evaluation approach, conducted in three phases. In phase one, eight managerial staff involved in developing and implementing the programme provided data, which were used to develop initial programme theories. In phase two, the programme theories were tested using qualitative data from 25 health visitors and 22 parents. The programme theories were refined through analyses and interpretation of data in phase three. The home visiting context provided by the programme interacted with the mechanisms of the programme and produced outcomes such as early identification of health and wellbeing issues amongst families who needed more support, leading to referral and engagement with sources of additional help. The home visits facilitated development of parent-health visitor relationships, and parents considered health visitors as their first point of contact on children's wellbeing and developmental-related issues. Moreover, the programme provided more clarity to health visitors' role, which in turn enhanced partnership working. However, there were aspects of the programme that may require further development. For instance, both parents and health visitors were concerned about the wide gaps between some home visits. The enhanced health visiting programme increased opportunities for monitoring and early identification of health and wellbeing concerns. It created structures for a more efficient partnership working and ensured that the needs of children and families were supported. These

  7. Toward Realistic Progenitors of Core-collapse Supernovae

    Science.gov (United States)

    Arnett, W. David; Meakin, Casey

    2011-06-01

    Two-dimensional (2D) hydrodynamical simulations of progenitor evolution of a 23 M sun star, close to core collapse (in ~1 hr in one dimension (1D)), with simultaneously active C, Ne, O, and Si burning shells, are presented and contrasted to existing 1D models (which are forced to be quasi-static). Pronounced asymmetries and strong dynamical interactions between shells are seen in 2D. Although instigated by turbulence, the dynamic behavior proceeds to sufficiently large amplitudes that it couples to the nuclear burning. Dramatic growth of low-order modes is seen as well as large deviations from spherical symmetry in the burning shells. The vigorous dynamics is more violent than that seen in earlier burning stages in the three-dimensional (3D) simulations of a single cell in the oxygen burning shell, or in 2D simulations not including an active Si shell. Linear perturbative analysis does not capture the chaotic behavior of turbulence (e.g., strange attractors such as that discovered by Lorenz), and therefore badly underestimates the vigor of the instability. The limitations of 1D and 2D models are discussed in detail. The 2D models, although flawed geometrically, represent a more realistic treatment of the relevant dynamics than existing 1D models, and present a dramatically different view of the stages of evolution prior to collapse. Implications for interpretation of SN1987A, abundances in young supernova remnants, pre-collapse outbursts, progenitor structure, neutron star kicks, and fallback are outlined. While 2D simulations provide new qualitative insight, fully 3D simulations are needed for a quantitative understanding of this stage of stellar evolution. The necessary properties of such simulations are delineated.

  8. The possibility of critical realist randomised controlled trials.

    Science.gov (United States)

    Porter, Sam; McConnell, Tracey; Reid, Joanne

    2017-03-21

    Some realists have criticised randomised controlled trials for their inability to explain the causal relations that they identify; to take into account the influence of the social context of the interventions they evaluate; and to account for individual difference. However, among realists, there is controversy over whether it is possible to improve trials by making them realist, or whether realism and the philosophical assumptions underlying trials are incompatible. This paper contributes to the debate in Trials on this issue. The debate thus far has concentrated on the possibility of combining trial methodology with that of realist evaluation. We concur with the contention that it is not feasible to combine randomised controlled trial design with the realist evaluation approach. However, we argue that a different variant of realism, critical realism, provides a more appropriate theoretical grounding for realist trials. In contrast to realist evaluation, which regards social mechanisms as an amalgam of social resources and people's reasoning, critical realism insists on their distinction. It does so on the basis of its assertion of the need to distinguish between social structures (in which resources lie) and human agency (which is at least partly guided by reasoning). From this perspective, conceiving of social mechanisms as external to participants can be seen as a valid methodological strategy for supplementing the exclusive concentration of trials on outcomes. While accepting realist evaluation's insistence that causality in open systems involves a configuration of multiple generative mechanisms, we adopt the critical realist interpretation of the experimental method, which sees it as creating artificial closure in order to identify the effects of specific causal mechanisms. If randomised controlled trials can be regarded as epidemiological proxies that substitute probabilistic controls over extraneous factors for closed experiments, their examination of the

  9. Modeling of ultrasonic wave propagation in composite laminates with realistic discontinuity representation.

    Science.gov (United States)

    Zelenyak, Andreea-Manuela; Schorer, Nora; Sause, Markus G R

    2017-06-20

    This paper presents a method for embedding realistic defect geometries of a fiber reinforced material in a finite element modeling environment in order to simulate active ultrasonic inspection. When ultrasonic inspection is used experimentally to investigate the presence of defects in composite materials, the microscopic defect geometry may cause signal characteristics that are difficult to interpret. Hence, modeling of this interaction is key to improve our understanding and way of interpreting the acquired ultrasonic signals. To model the true interaction of the ultrasonic wave field with such defect structures as pores, cracks or delamination, a realistic three dimensional geometry reconstruction is required. We present a 3D-image based reconstruction process which converts computed tomography data in adequate surface representations ready to be embedded for processing with finite element methods. Subsequent modeling using these geometries uses a multi-scale and multi-physics simulation approach which results in quantitative A-Scan ultrasonic signals which can be directly compared with experimental signals. Therefore, besides the properties of the composite material, a full transducer implementation, piezoelectric conversion and simultaneous modeling of the attached circuit is applied. Comparison between simulated and experimental signals provides very good agreement in electrical voltage amplitude and the signal arrival time and thus validates the proposed modeling approach. Simulating ultrasound wave propagation in a medium with a realistic shape of the geometry clearly shows a difference in how the disturbance of the waves takes place and finally allows more realistic modeling of A-scans. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effective interactions for light nuclei: an effective (field theory) approach

    OpenAIRE

    Stetcu, I.; Rotureau, J.; Barrett, B.R.; van Kolck, U.

    2009-01-01

    One of the central open problems in nuclear physics is the construction of effective interactions suitable for many-body calculations. We discuss a recently developed approach to this problem, where one starts with an effective field theory containing only fermion fields and formulated directly in a no-core shell-model space. We present applications to light nuclei and to systems of a few atoms in a harmonic-oscillator trap. Future applications and extensions, as well as challenges, are also ...

  11. Configuration mixing in the sdg interacting boson model

    Energy Technology Data Exchange (ETDEWEB)

    Bouldjedri, A [Department of Physics, Faculty of Science, University of Batna, Avenue Boukhelouf M El Hadi, 05000 Batna (Algeria); Van Isacker, P [GANIL, BP 55027, F-14076 Caen cedex 5 (France); Zerguine, S [Department of Physics, Faculty of Science, University of Batna, Avenue Boukhelouf M El Hadi, 05000 Batna (Algeria)

    2005-11-01

    A wavefunction analysis of the strong-coupling limits of the sdg interacting boson model is presented. The analysis is carried out for two-boson states and allows us to characterize the boson configuration mixing in the different limits. Based on these results and those of a shell-model analysis of the sdg IBM, qualitative conclusions are drawn about the range of applicability of each limit.

  12. The construction of context-mechanisms-outcomes in realistic evaluation.

    Science.gov (United States)

    Linsley, Paul; Howard, David; Owen, Sara

    2015-01-01

    To discuss the construction of context-mechanisms-outcomes (CMOs) developed as part of a realistic evaluation study of two aggression management training programmes. Realistic evaluation draws on theories and methods derived from the social sciences. It provides a distinctive account of the nature of programmes and how they work. Realistic evaluation is a form of evaluation that is driven by theory, and was based by Pawson and Tilley ( 1997 ) on the philosophy of critical realism. Critical realism is an important perspective in modern philosophy and social science, but it is largely absent in the field of healthcare research. This paper provides a critical discussion on the construction of CMOs as part of a realistic evaluation study. This paper draws on the personal experiences of the author in using realistic evaluation to evaluate training in aggression management. Realistic evaluation stresses four key linked concepts for explaining and understanding programmes: 'mechanism', 'context', 'outcome pattern' and 'context-mechanisms-outcomes (CMO) pattern configuration'. A CMO configuration is a proposition stating what it is about an initiative that works, for whom and in what circumstances. In this way, the effectiveness of the programme is understood, with an explanation of why the outcomes developed as they did and how the programme was able to react to underlying mechanisms and in what contexts. Therefore, a realistic evaluation researcher is not just inspecting outcomes to see if an initiative (implementation) works, but is analysing the outcomes to discover if the conjectured mechanism or context theories are confirmed. This analysis provides not only evidence of effectiveness, but also an explanation that helps to develop and improve the content and the targeting of future programmes. The development of CMOs requires a great deal of skill on the part of the researcher and requires a flexibility of approach when collecting and analysing the data and in

  13. Problem Posing with Realistic Mathematics Education Approach in Geometry Learning

    Science.gov (United States)

    Mahendra, R.; Slamet, I.; Budiyono

    2017-09-01

    One of the difficulties of students in the learning of geometry is on the subject of plane that requires students to understand the abstract matter. The aim of this research is to determine the effect of Problem Posing learning model with Realistic Mathematics Education Approach in geometry learning. This quasi experimental research was conducted in one of the junior high schools in Karanganyar, Indonesia. The sample was taken using stratified cluster random sampling technique. The results of this research indicate that the model of Problem Posing learning with Realistic Mathematics Education Approach can improve students’ conceptual understanding significantly in geometry learning especially on plane topics. It is because students on the application of Problem Posing with Realistic Mathematics Education Approach are become to be active in constructing their knowledge, proposing, and problem solving in realistic, so it easier for students to understand concepts and solve the problems. Therefore, the model of Problem Posing learning with Realistic Mathematics Education Approach is appropriately applied in mathematics learning especially on geometry material. Furthermore, the impact can improve student achievement.

  14. Breaking with fun, educational and realistic learning games

    DEFF Research Database (Denmark)

    Duus Henriksen, Thomas

    2009-01-01

    between the game and other didactic activities that formed the learning process; and, the game might have been intended to be realistic, but it was in the gaps where this realism was critically assessed that learned understanding was forged. While thinking learning games as fun, educative and realistic......This paper addresses the game conceptions and values that learning games inherit from regular gaming, as well as how they affect the use and development of learning games. Its key points concern the issues of thinking learning games as fun, educative and realistic, which is how learning games...... are commonly conceived as means for staging learning processes, and that thinking learning games so has an inhibiting effect in regard to creating learning processes. The paper draws upon a qualitative study of participants' experiences with ‘the EIS Simulation', which is a computer-based learning game...

  15. Survey of Approaches to Generate Realistic Synthetic Graphs

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Seung-Hwan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Sangkeun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Sarah S [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shankar, Mallikarjun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Imam, Neena [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-01

    A graph is a flexible data structure that can represent relationships between entities. As with other data analysis tasks, the use of realistic graphs is critical to obtaining valid research results. Unfortunately, using the actual ("real-world") graphs for research and new algorithm development is difficult due to the presence of sensitive information in the data or due to the scale of data. This results in practitioners developing algorithms and systems that employ synthetic graphs instead of real-world graphs. Generating realistic synthetic graphs that provide reliable statistical confidence to algorithmic analysis and system evaluation involves addressing technical hurdles in a broad set of areas. This report surveys the state of the art in approaches to generate realistic graphs that are derived from fitted graph models on real-world graphs.

  16. Putting a Realistic Theory of Mind into Agency Theory

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Stea, Diego

    2014-01-01

    Agency theory is one of the most important foundational theories in management research, but it rests on contestable cognitive assumptions. Specifically, the principal is assumed to hold a perfect (correct) theory regarding some of the content of the agent's mind, while he is entirely ignorant...... concerning other such content. More realistically, individuals have some limited access to the minds of others. We explore the implications for classical agency theory of realistic assumptions regarding the human potential for interpersonal sensemaking. We discuss implications for the design and management...

  17. Simulating autosomal genotypes with realistic linkage disequilibrium and a spiked-in genetic effect.

    Science.gov (United States)

    Shi, M; Umbach, D M; Wise, A S; Weinberg, C R

    2018-01-02

    To evaluate statistical methods for genome-wide genetic analyses, one needs to be able to simulate realistic genotypes. We here describe a method, applicable to a broad range of association study designs, that can simulate autosome-wide single-nucleotide polymorphism data with realistic linkage disequilibrium and with spiked in, user-specified, single or multi-SNP causal effects. Our construction uses existing genome-wide association data from unrelated case-parent triads, augmented by including a hypothetical complement triad for each triad (same parents but with a hypothetical offspring who carries the non-transmitted parental alleles). We assign offspring qualitative or quantitative traits probabilistically through a specified risk model and show that our approach destroys the risk signals from the original data. Our method can simulate genetically homogeneous or stratified populations and can simulate case-parents studies, case-control studies, case-only studies, or studies of quantitative traits. We show that allele frequencies and linkage disequilibrium structure in the original genome-wide association sample are preserved in the simulated data. We have implemented our method in an R package (TriadSim) which is freely available at the comprehensive R archive network. We have proposed a method for simulating genome-wide SNP data with realistic linkage disequilibrium. Our method will be useful for developing statistical methods for studying genetic associations, including higher order effects like epistasis and gene by environment interactions.

  18. The visualizable, the representable and the inconceivable: realist and non-realist mathematical models in physics and beyond.

    Science.gov (United States)

    Plotnitsky, Arkady

    2016-01-13

    The project of this article is twofold. First, it aims to offer a new perspective on, and a new argument concerning, realist and non-realist mathematical models, and differences and affinities between them, using physics as a paradigmatic field of mathematical modelling in science. Most of the article is devoted to this topic. Second, the article aims to explore the implications of this argument for mathematical modelling in other fields, in particular in cognitive psychology and economics. © 2015 The Author(s).

  19. Dark matter effect on realistic equation of state in neutron stars

    Science.gov (United States)

    Panotopoulos, Grigorios; Lopes, Ilídio

    2017-10-01

    In this work, we apply relativistic mean-field theory in neutron stars assuming that fermionic dark matter is trapped inside the star and interacts directly with neutrons by exchanging standard model Higgs bosons. For realistic values of the parameters of the model, we compute numerically the equation of state, and we compare it to the standard one. Furthermore, the mass-to-radius relation for both equations of state (pure neutron matter as well as admixed DM-neutron star) is shown, and the highest star mass for both cases is reported.

  20. Using a Realist Research Methodology in Policy Analysis

    Science.gov (United States)

    Lourie, Megan; Rata, Elizabeth

    2017-01-01

    The article describes the usefulness of a realist methodology in linking sociological theory to empirically obtained data through the development of a methodological device. Three layers of analysis were integrated: 1. the findings from a case study about Maori language education in New Zealand; 2. the identification and analysis of contradictions…

  1. Rethinking Mathematics Teaching in Liberia: Realistic Mathematics Education

    Science.gov (United States)

    Stemn, Blidi S.

    2017-01-01

    In some African cultures, the concept of division does not necessarily mean sharing money or an item equally. How an item is shared might depend on the ages of the individuals involved. This article describes the use of the Realistic Mathematics Education (RME) approach to teach division word problems involving money in a 3rd-grade class in…

  2. Generalized Warburg impedance on realistic self-affine fractals ...

    Indian Academy of Sciences (India)

    Administrator

    Generalized Warburg impedance on realistic self-affine fractals: Comparative study of statistically corrugated and isotropic roughness. RAJESH KUMAR and RAMA KANT. Journal of Chemical Sciences, Vol. 121, No. 5, September 2009, pp. 579–588. 1. ( ) c. L. R ω on page 582, column 2, para 2, after eq (8) should read as ...

  3. Hope in Janusz Korczak's Pedagogy of Realistic Idealism

    Science.gov (United States)

    Silverman, Marc

    2017-01-01

    This article explores the approach of "Realistic Idealism" to moral education developed by the humanist-progressive moral educator Janusz Korczak, and the role hope plays in it. This pair of terms seems to be an oxymoron. However, their employment is intentional and the article will demonstrate their dialectical interdependence:…

  4. Parallel Evolutionary Peer-to-Peer Networking in Realistic Environments

    Directory of Open Access Journals (Sweden)

    Kei Ohnishi

    2017-01-01

    Full Text Available In the present paper we first conduct simulations of the parallel evolutionary peer-to-peer (P2P networking technique (referred to as P-EP2P that we previously proposed using models of realistic environments to examine if P-EP2P is practical. Environments are here represented by what users have and want in the network, and P-EP2P adapts the P2P network topologies to the present environment in an evolutionary manner. The simulation results show that P-EP2P is hard to adapt the network topologies to some realistic environments. Then, based on the discussions of the results, we propose a strategy for better adaptability of P-EP2P to the realistic environments. The strategy first judges if evolutionary adaptation of the network topologies is likely to occur in the present environment, and if it judges so, it actually tries to achieve evolutionary adaptation of the network topologies. Otherwise, it brings random change to the network topologies. The simulation results indicate that P-EP2P with the proposed strategy can better adapt the network topologies to the realistic environments. The main contribution of the study is to present such a promising way to realize an evolvable network in which the evolution direction is given by users.

  5. Use of supersymmetric isospectral formalism to realistic quantum ...

    Indian Academy of Sciences (India)

    to realistic quantum many-body problems. BARNALI CHAKRABARTI. Department of Physics, Lady Brabourne College, P1/2 Suhrawardy Avenue,. Kolkata 700 017, India. E-mail: chakb@rediffmail.com. Abstract. We propose a novel mathematical approach for the calculation of resonances in weakly bound systems. For any ...

  6. Improving Mathematics Teaching in Kindergarten with Realistic Mathematical Education

    Science.gov (United States)

    Papadakis, Stamatios; Kalogiannakis, Michail; Zaranis, Nicholas

    2017-01-01

    The present study investigates and compares the influence of teaching Realistic Mathematics on the development of mathematical competence in kindergarten. The sample consisted of 231 Greek kindergarten students. For the implementation of the survey, we conducted an intervention, which included one experimental and one control group. Children in…

  7. Towards a Realist Sociology of Education: A Polyphonic Review Essay

    Science.gov (United States)

    Grenfell, Michael; Hood, Susan; Barrett, Brian D.; Schubert, Dan

    2017-01-01

    This review essay evaluates Karl Maton's "Knowledge and Knowers: Towards a Realist Sociology of Education" as a recent examination of the sociological causes and effects of education in the tradition of the French social theorist Pierre Bourdieu and the British educational sociologist Basil Bernstein. Maton's book synthesizes the…

  8. Evaluation of Highly Realistic Training for Independent Duty Corpsmen Students

    Science.gov (United States)

    2015-05-21

    that he or she can perform desired actions or behaviors ( Bandura , 1977). In the present study, three types of self-efficacy were assessed: general...such as resilience. IDC Highly Realistic Training 10 REFERENCES Bandura , A (1977). Self-efficacy: Toward a unifying theory of behavioral

  9. Use of supersymmetric isospectral formalism to realistic quantum ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 73; Issue 2. Use of supersymmetric isospectral formalism to realistic quantum many-body problems ... state in the original shallow potential will be effectively trapped in the deep well of the isospectral family, facilitating more accurate calculation of resonance energy.

  10. Empirical Evidence for Niss' "Implemented Anticipation" in Mathematising Realistic Situations

    Science.gov (United States)

    Stillman, Gloria; Brown, Jill P.

    2012-01-01

    Mathematisation of realistic situations is an on-going focus of research. Classroom data from a Year 9 class participating in a program of structured modelling of real situations was analysed for evidence of Niss's theoretical construct, implemented anticipation, during mathematisation. Evidence was found for two of three proposed aspects. In…

  11. An Overview of Westinghouse Realistic Large Break LOCA Evaluation Model

    Directory of Open Access Journals (Sweden)

    Cesare Frepoli

    2008-01-01

    Full Text Available Since the 1988 amendment of the 10 CFR 50.46 rule in 1988, Westinghouse has been developing and applying realistic or best-estimate methods to perform LOCA safety analyses. A realistic analysis requires the execution of various realistic LOCA transient simulations where the effect of both model and input uncertainties are ranged and propagated throughout the transients. The outcome is typically a range of results with associated probabilities. The thermal/hydraulic code is the engine of the methodology but a procedure is developed to assess the code and determine its biases and uncertainties. In addition, inputs to the simulation are also affected by uncertainty and these uncertainties are incorporated into the process. Several approaches have been proposed and applied in the industry in the framework of best-estimate methods. Most of the implementations, including Westinghouse, follow the Code Scaling, Applicability and Uncertainty (CSAU methodology. Westinghouse methodology is based on the use of the WCOBRA/TRAC thermal-hydraulic code. The paper starts with an overview of the regulations and its interpretation in the context of realistic analysis. The CSAU roadmap is reviewed in the context of its implementation in the Westinghouse evaluation model. An overview of the code (WCOBRA/TRAC and methodology is provided. Finally, the recent evolution to nonparametric statistics in the current edition of the W methodology is discussed. Sample results of a typical large break LOCA analysis for a PWR are provided.

  12. Generalized Warburg impedance on realistic self-affine fractals ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 5. Generalized Warburg impedance on realistic self-affine fractals: Comparative study of statistically corrugated and isotropic roughness. Rajesh Kumar Rama Kant. Volume 121 Issue 5 September 2009 pp ...

  13. Place of a Realistic Teacher Education Pedagogy in an ICT ...

    African Journals Online (AJOL)

    This article is based on a study undertaken to examine the impact of introducing a realistic teacher education pedagogy (RTEP) oriented learning environment supported by ICT on distance teacher education in Uganda. It gives an overview of the quality, quantity and training of teachers in primary and secondary schools

  14. The Potential and Challenges of Critical Realist Ethnography

    Science.gov (United States)

    Barron, Ian

    2013-01-01

    This article revisits the critical realist ethnographic process that was adopted in my doctoral thesis, which was concerned with the experiences of ethnic identity of white British and Pakistani British children as they started kindergarten in the northwest of England. The article focuses on the ethnography that emerged from the visits that I…

  15. Creating a Realistic Context for Team Projects in HCI

    NARCIS (Netherlands)

    Koppelman, Hermannus; van Dijk, Elisabeth M.A.G.

    2006-01-01

    Team projects are nowadays common practice in HCI education. This paper focuses on the role of clients and users in team projects in introductory HCI courses. In order to provide projects with a realistic context we invite people from industry to serve as clients for the student teams. Some of them

  16. Realist synthesis: illustrating the method for implementation research

    Directory of Open Access Journals (Sweden)

    Rycroft-Malone Jo

    2012-04-01

    Full Text Available Abstract Background Realist synthesis is an increasingly popular approach to the review and synthesis of evidence, which focuses on understanding the mechanisms by which an intervention works (or not. There are few published examples of realist synthesis. This paper therefore fills a gap by describing, in detail, the process used for a realist review and synthesis to answer the question ‘what interventions and strategies are effective in enabling evidence-informed healthcare?’ The strengths and challenges of conducting realist review are also considered. Methods The realist approach involves identifying underlying causal mechanisms and exploring how they work under what conditions. The stages of this review included: defining the scope of the review (concept mining and framework formulation; searching for and scrutinising the evidence; extracting and synthesising the evidence; and developing the narrative, including hypotheses. Results Based on key terms and concepts related to various interventions to promote evidence-informed healthcare, we developed an outcome-focused theoretical framework. Questions were tailored for each of four theory/intervention areas within the theoretical framework and were used to guide development of a review and data extraction process. The search for literature within our first theory area, change agency, was executed and the screening procedure resulted in inclusion of 52 papers. Using the questions relevant to this theory area, data were extracted by one reviewer and validated by a second reviewer. Synthesis involved organisation of extracted data into evidence tables, theming and formulation of chains of inference, linking between the chains of inference, and hypothesis formulation. The narrative was developed around the hypotheses generated within the change agency theory area. Conclusions Realist synthesis lends itself to the review of complex interventions because it accounts for context as well as

  17. Effects of realistic force feedback in a robotic assisted minimally invasive surgery system.

    Science.gov (United States)

    Moradi Dalvand, Mohsen; Shirinzadeh, Bijan; Nahavandi, Saeid; Smith, Julian

    2014-06-01

    Robotic assisted minimally invasive surgery systems not only have the advantages of traditional laparoscopic procedures but also restore the surgeon's hand-eye coordination and improve the surgeon's precision by filtering hand tremors. Unfortunately, these benefits have come at the expense of the surgeon's ability to feel. Several research efforts have already attempted to restore this feature and study the effects of force feedback in robotic systems. The proposed methods and studies have some shortcomings. The main focus of this research is to overcome some of these limitations and to study the effects of force feedback in palpation in a more realistic fashion. A parallel robot assisted minimally invasive surgery system (PRAMiSS) with force feedback capabilities was employed to study the effects of realistic force feedback in palpation of artificial tissue samples. PRAMiSS is capable of actually measuring the tip/tissue interaction forces directly from the surgery site. Four sets of experiments using only vision feedback, only force feedback, simultaneous force and vision feedback and direct manipulation were conducted to evaluate the role of sensory feedback from sideways tip/tissue interaction forces with a scale factor of 100% in characterising tissues of varying stiffness. Twenty human subjects were involved in the experiments for at least 1440 trials. Friedman and Wilcoxon signed-rank tests were employed to statistically analyse the experimental results. Providing realistic force feedback in robotic assisted surgery systems improves the quality of tissue characterization procedures. Force feedback capability also increases the certainty of characterizing soft tissues compared with direct palpation using the lateral sides of index fingers. The force feedback capability can improve the quality of palpation and characterization of soft tissues of varying stiffness by restoring sense of touch in robotic assisted minimally invasive surgery operations.

  18. Randomly interacting bosons on two spin levels

    Science.gov (United States)

    Mulhall, D.

    2017-12-01

    The problem of random interactions leading to regular spectra in shell model type simulations is described. The key results are reviewed alnog with a selection of the explanations. A model system of N particles on 2 spin levels having random 2-body collisions that conserve angular momentum is examined. Preliminary results are described, including the ground state spin distributions peaked at extreme values of angular momentum, signatures of rotational bands, and smooth parabolic yrast lines. A simple random matrix theory analysis shows signatures of quantum chaos in the level spacing distribution and the Δ3 statistic.

  19. Probing Chiral Interactions in Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P

    2004-01-08

    Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.

  20. Protocol for a realist review of workplace learning in postgraduate medical education and training.

    Science.gov (United States)

    Wiese, Anel; Kilty, Caroline; Bergin, Colm; Flood, Patrick; Fu, Na; Horgan, Mary; Higgins, Agnes; Maher, Bridget; O'Kane, Grainne; Prihodova, Lucia; Slattery, Dubhfeasa; Bennett, Deirdre

    2017-01-19

    Postgraduate medical education and training (PGMET) is a complex social process which happens predominantly during the delivery of patient care. The clinical learning environment (CLE), the context for PGMET, shapes the development of the doctors who learn and work within it, ultimately impacting the quality and safety of patient care. Clinical workplaces are complex, dynamic systems in which learning emerges from non-linear interactions within a network of related factors and activities. Those tasked with the design and delivery of postgraduate medical education and training need to understand the relationship between the processes of medical workplace learning and these contextual elements in order to optimise conditions for learning. We propose to conduct a realist synthesis of the literature to address the overarching questions; how, why and in what circumstances do doctors learn in clinical environments? This review is part of a funded projected with the overall aim of producing guidelines and recommendations for the design of high quality clinical learning environments for postgraduate medical education and training. We have chosen realist synthesis as a methodology because of its suitability for researching complexity and producing answers useful to policymakers and practitioners. This realist synthesis will follow the steps and procedures outlined by Wong et al. in the RAMESES Publication Standards for Realist Synthesis and the Realist Synthesis RAMESES Training Materials. The core research team is a multi-disciplinary group of researchers, clinicians and health professions educators. The wider research group includes experts in organisational behaviour and human resources management as well as the key stakeholders; doctors in training, patient representatives and providers of PGMET. This study will draw from the published literature and programme, and substantive, theories of workplace learning, to describe context, mechanism and outcome configurations for

  1. Vertical Velocities in Cumulus Convection: Implications for Climate and Prospects for Realistic Simulation at Cloud Scale

    Science.gov (United States)

    Donner, Leo

    2014-05-01

    Cumulus mass fluxes are essential controls on the interactions between cumulus convection and large-scale flows. Cumulus parameterizations have generally been built around them, and these parameterizations are basic components of climate models. Several important questions in climate science depend also on cumulus vertical velocities. Interactions between aerosols and convection comprise a prominent example, and scale-aware cumulus parameterizations that require explicit information about cumulus areas are another. Basic progress on these problems requires realistic characterization of cumulus vertical velocities from observations and models. Recent deployments of dual-Doppler radars are providing unprecedented observations, which can be compared against cloud-resolving models (CRMs). The CRMs can subsequently be analyzed to develop and evaluate parameterizations of vertical velocities in climate models. Vertical velocities from several cloud models will be compared against observations in this presentation. CRM vertical velocities will be found to depend strongly on model resolution and treatment of sub-grid turbulence and microphysics. Although many current state-of-science CRMs do not simulate vertical velocities well, recent experiments with these models suggest that with appropriate treatments of sub-grid turbulence and microphysics robustly realistic modeling of cumulus vertical velocities is possible.

  2. The work is never ending: uncovering teamwork sustainability using realistic evaluation.

    Science.gov (United States)

    Frykman, Mandus; von Thiele Schwarz, Ulrica; Muntlin Athlin, Åsa; Hasson, Henna; Mazzocato, Pamela

    2017-03-20

    Purpose The purpose of this paper is to uncover the mechanisms influencing the sustainability of behavior changes following the implementation of teamwork. Design/methodology/approach Realistic evaluation was combined with a framework (DCOM®) based on applied behavior analysis to study the sustainability of behavior changes two and a half years after the initial implementation of teamwork at an emergency department. The DCOM® framework was used to categorize the mechanisms of behavior change interventions (BCIs) into the four categories of direction, competence, opportunity, and motivation. Non-participant observation and interview data were used. Findings The teamwork behaviors were not sustained. A substantial fallback in managerial activities in combination with a complex context contributed to reduced direction, opportunity, and motivation. Reduced direction made staff members unclear about how and why they should work in teams. Deterioration of opportunity was evident from the lack of problem-solving resources resulting in accumulated barriers to teamwork. Motivation in terms of management support and feedback was reduced. Practical implications The implementation of complex organizational changes in complex healthcare contexts requires continuous adaption and managerial activities well beyond the initial implementation period. Originality/value By integrating the DCOM® framework with realistic evaluation, this study responds to the call for theoretically based research on behavioral mechanisms that can explain how BCIs interact with context and how this interaction influences sustainability.

  3. Realistic electricity market simulator for energy and economic studies

    Energy Technology Data Exchange (ETDEWEB)

    Bernal-Agustin, Jose L. [University of Zaragoza, C/Maria de Luna, 3, Zaragoza 50018 (Spain); Contreras, Javier; Conejo, Antonio J. [University of Castilla-La Mancha, Campus Universitario s/n, Ciudad Real 13071 (Spain); Martin-Flores, Raul [Airbus Spain S.L., Paseo John Lennon, Getafe 28906 (Spain)

    2007-01-15

    Electricity market simulators have become a useful tool to train engineers in the power industry. With the maturing of electricity markets throughout the world, there is a need for sophisticated software tools that can replicate the actual behavior of power markets. In most of these markets, power producers/consumers submit production/demand bids and the Market Operator clears the market producing a single price per hour. What makes markets different from each other are the bidding rules and the clearing algorithms to balance the market. This paper presents a realistic simulator of the day-ahead electricity market of mainland Spain. All the rules that govern this market are modeled. This simulator can be used either to train employees by power companies or to teach electricity markets courses in universities. To illustrate the tool, several realistic case studies are presented and discussed. (author)

  4. A general realistic treatment of the disk paradox

    CERN Document Server

    Pantazis, George

    2016-01-01

    Mechanical angular momentum is not conserved in systems involving electromagnetic fields with non-zero electromagnetic field angular momentum. Conservation is restored only if the total (mechanical and field) angular momentum is considered. Previous studies have investigated this effect, known as "Feynman's Electromagnetic Paradox" or simply "Disk Paradox" in the context of idealized systems (infinite or infinitesimal solenoids and charged cylinders \\etc). In the present analysis we generalize previous studies by considering more realistic systems with finite components and demonstrating explicitly the conservation of the total angular momentum. This is achieved by expressing both the mechanical and the field angular momentum in terms of charges and magnetic field fluxes through various system components. Using this general expression we demonstrate explicitly the conservation of total angular momentum in both idealized and realistic systems (finite solenoid concentric with two charged long cylinders) taking ...

  5. Realistic animation of human figures using artificial neural networks.

    Science.gov (United States)

    Taha, Z; Brown, R; Wright, D

    1996-12-01

    We describe a new approach to the animation of human figures which can produce realistic animation and based on artificial neural networks (ANN). A fully connected ANN is trained with inputs and outputs of key frames obtained from image analysis and key postures and parameters of standing, walking and running. A behaviour index is introduced as an input to the ANN. Each index is unique to each behaviour. Other inputs include speed, cycle history and subsystem index. The subsystem index refers to the different subsystem of the human figure e.g. the right leg is a subsystem referred to by an index. The outputs are the joints displacements. The ANN is trained using the back propagation method. The ANN was able to generate realistic animations of walking and running and could merge three different behaviours, standing, walking and running. The proposed method should enable design evaluations, human factors analysis, task simulation and motion understanding easier for non-animation experts.

  6. Realistic Visualization of Virtual Views and Virtual Cinema

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    Realistic Virtual View Visualization is a new field of research which has received increasing attention in recent years. It is strictly related to the increased popularity of virtual reality and the spread of its applications, among which virtual photography and cinematography. The use of computer...... generated characters, "virtual actors", in the motion picture production increases every day. While the most known computer graphics techniques have largely been adopted successfully in nowadays fictions, it still remains very challenging to implement virtual actors which would resemble, visually, human...... beings. Interestingly, film directors have been looking at the recent progress achieved by the research community in the field of realistic visualization of virtual views, and they have successfully implemented state of the art research approaches in their productions. An innovative concept...

  7. Direct Numerical Simulation of Multiphase flow over Realistic Superhydrophobic Surfaces

    Science.gov (United States)

    Alame, Karim; Mahesh, Krishnan

    2017-11-01

    Direct numerical simulations are performed using the volume of fluid methodology, for turbulent channel flow of water over a realistic superhydrophobic surface, which traps air. The surface is obtained from scanned data of the real sprayed surface. Multiphase laminar Couette flow and turbulent channel cases are examined. Drag reduction for different interface heights are shown, and the effect of turbulence on multiphase flow over rough surfaces is discussed. This work is supported by the Office of Naval Research.

  8. $\\infty-$Dimensional Cerebellar Controller for Realistic Human Biodynamics

    OpenAIRE

    Ivancevic, Vladimir G.; Ivancevic, Tijana T.

    2008-01-01

    In this paper we propose an $\\infty-$dimensional cerebellar model of neural controller for realistic human biodynamics. The model is developed using Feynman's action-amplitude (partition function) formalism. The cerebellum controller is acting as a supervisor for an autogenetic servo control of human musculo-skeletal dynamics, which is presented in (dissipative, driven) Hamiltonian form. The $\\infty-$dimensional cerebellar controller is closely related to entropic motor control. Keywords: rea...

  9. Parachute landing fall characteristics at three realistic vertical descent velocities.

    Science.gov (United States)

    Whitting, John W; Steele, Julie R; Jaffrey, Mark A; Munro, Bridget J

    2007-12-01

    Although parachute landing injuries are thought to be due in part to a lack of exposure of trainees to realistic descent velocities during parachute landing fall (PLF) training, no research has systematically investigated whether PLF technique is affected by different vertical descent conditions, with standardized and realistic conditions of horizontal drift. This study was designed to determine the effects of variations in vertical descent velocity on PLF technique. Kinematic, ground reaction force, and electromyographic data were collected and analyzed for 20 paratroopers while they performed parachute landings, using a custom-designed monorail apparatus, with a constant horizontal drift velocity (2.3 m x s(-1)) and at three realistic vertical descent velocities: slow (2.1 m x s(-1)), medium (3.3 m x s(-1)), and fast (4.6 m x s(-1)). Most biomechanical variables characterizing PLF technique were significantly affected by descent velocity. For example, at the fast velocity, the subjects impacted the ground with 123 degrees of plantar flexion and generated ground reaction forces averaging 13.7 times body weight, compared to 106 degrees and 6.1 body weight, respectively, at the slow velocity. Furthermore, the subjects activated their antigravity extensor muscles earlier during the fast velocity condition to eccentrically control the impact absorption. As vertical descent rates increased, the paratroopers displayed a significantly different strategy when performing the PLF. It is therefore recommended that PLF training programs include ground training activities with realistic vertical descent velocities to better prepare trainees to withstand the impact forces associated with initial aerial descents onto the Drop Zone and, ultimately, minimize the potential for injury.

  10. Antara Realistic Mathematics Education (RME dengan Matematika Modern (New Math

    Directory of Open Access Journals (Sweden)

    Darhima Darhima

    2016-02-01

    Full Text Available The effectiveness of new mathematics, which has been implemented in Indonesia for 29 years, in increasing student achievement is still in question. Starting from two or three years ago, Indonesia has tried out a new kind of approach in teaching mathematics, the so called Realistic Mathematics Education (RME. This article portrays the similarities and differences between these two approaches, discussing the strengths and weaknesses of each approach.

  11. Antara Realistic Mathematics Education (RME) dengan Matematika Modern (New Math)

    OpenAIRE

    Darhima Darhima; Hamzah Hamzah

    2016-01-01

    The effectiveness of new mathematics, which has been implemented in Indonesia for 29 years, in increasing student achievement is still in question. Starting from two or three years ago, Indonesia has tried out a new kind of approach in teaching mathematics, the so called Realistic Mathematics Education (RME). This article portrays the similarities and differences between these two approaches, discussing the strengths and weaknesses of each approach.

  12. Relating realist metatheory to issues of gender and mental health.

    Science.gov (United States)

    Bergin, M; Wells, John S G; Owen, Sara

    2010-06-01

    This paper seeks to advance the debate that considers critical realism as an alternative approach for understanding gender and mental health and its relatedness to mental health research and practice. The knowledge base of how 'sex' and 'gender' affect mental health and illness is expanding. However, the way we conceptualize gender is significant and challenging as quite often our ability to think about 'gender' as independent of 'sex' is not common. The influences and interplay of how sex (biological) and gender (social) affect mental health and illness requires consideration. Critical realism suggests a shared ontology and epistemology for the natural and social sciences. While much of the debate surrounding gender is guided within a constructivist discourse, an exploration of the concept 'gender' is reflected on and some key realist propositions are considered for mental health research and practice. This is achieved through the works of some key realist theorists. Critical realism offers potential for research and practice in relation to gender and mental health because it facilitates changes in our understanding, while simultaneously, not discarding that which is already known. In so doing, it allows the biological (sex) and social (gender) domains of knowledge for mental health and illness to coexist, without either being reduced to or defined by the other. Arguably, greater depth and explanations for gender and mental health issues are presented within a realist metatheory.

  13. Near-realistic mobile exergames with wireless wearable sensors.

    Science.gov (United States)

    Mortazavi, Bobak; Nyamathi, Suneil; Lee, Sunghoon Ivan; Wilkerson, Thomas; Ghasemzadeh, Hassan; Sarrafzadeh, Majid

    2014-03-01

    Exergaming is expanding as an option for sedentary behavior in childhood/adult obesity and for extra exercise for gamers. This paper presents the development process for a mobile active sports exergame with near-realistic motions through the usage of body-wearable sensors. The process begins by collecting a dataset specifically targeted to mapping real-world activities directly to the games, then, developing the recognition system in a fashion to produce an enjoyable game. The classification algorithm in this paper has precision and recall of 77% and 77% respectively, compared with 40% and 19% precision and recall on current activity monitoring algorithms intended for general daily living activities. Aside from classification, the user experience must be strong enough to be a successful system for adoption. Indeed, fast and intense activities as well as competitive, multiplayer environments make for a successful, enjoyable exergame. This enjoyment is evaluated through a 30 person user study. Multiple aspects of the exergaming user experience trials have been merged into a comprehensive survey, called ExerSurvey. All but one user thought the motions in the game were realistic and difficult to cheat. Ultimately, a game with near-realistic motions was shown to be an enjoyable, active video exergame for any environment.

  14. A Fibrocontractive Mechanochemical Model of Dermal Wound Closure Incorporating Realistic Growth Factor Kinetics

    KAUST Repository

    Murphy, Kelly E.

    2012-01-13

    Fibroblasts and their activated phenotype, myofibroblasts, are the primary cell types involved in the contraction associated with dermal wound healing. Recent experimental evidence indicates that the transformation from fibroblasts to myofibroblasts involves two distinct processes: The cells are stimulated to change phenotype by the combined actions of transforming growth factor β (TGFβ) and mechanical tension. This observation indicates a need for a detailed exploration of the effect of the strong interactions between the mechanical changes and growth factors in dermal wound healing. We review the experimental findings in detail and develop a model of dermal wound healing that incorporates these phenomena. Our model includes the interactions between TGFβ and collagenase, providing a more biologically realistic form for the growth factor kinetics than those included in previous mechanochemical descriptions. A comparison is made between the model predictions and experimental data on human dermal wound healing and all the essential features are well matched. © 2012 Society for Mathematical Biology.

  15. New insights into defibrillation of the heart from realistic simulation studies.

    Science.gov (United States)

    Trayanova, Natalia A; Rantner, Lukas J

    2014-05-01

    Cardiac defibrillation, as accomplished nowadays by automatic, implantable devices, constitutes the most important means of combating sudden cardiac death. Advancing our understanding towards a full appreciation of the mechanisms by which a shock interacts with the heart, particularly under diseased conditions, is a promising approach to achieve an optimal therapy. The aim of this article is to assess the current state-of-the-art in whole-heart defibrillation modelling, focusing on major insights that have been obtained using defibrillation models, primarily those of realistic heart geometry and disease remodelling. The article showcases the contributions that modelling and simulation have made to our understanding of the defibrillation process. The review thus provides an example of biophysically based computational modelling of the heart (i.e. cardiac defibrillation) that has advanced the understanding of cardiac electrophysiological interaction at the organ level, and has the potential to contribute to the betterment of the clinical practice of defibrillation.

  16. A realistic evaluation: the case of protocol-based care

    Science.gov (United States)

    2010-01-01

    Background 'Protocol based care' was envisioned by policy makers as a mechanism for delivering on the service improvement agenda in England. Realistic evaluation is an increasingly popular approach, but few published examples exist, particularly in implementation research. To fill this gap, within this paper we describe the application of a realistic evaluation approach to the study of protocol-based care, whilst sharing findings of relevance about standardising care through the use of protocols, guidelines, and pathways. Methods Situated between positivism and relativism, realistic evaluation is concerned with the identification of underlying causal mechanisms, how they work, and under what conditions. Fundamentally it focuses attention on finding out what works, for whom, how, and in what circumstances. Results In this research, we were interested in understanding the relationships between the type and nature of particular approaches to protocol-based care (mechanisms), within different clinical settings (context), and what impacts this resulted in (outcomes). An evidence review using the principles of realist synthesis resulted in a number of propositions, i.e., context, mechanism, and outcome threads (CMOs). These propositions were then 'tested' through multiple case studies, using multiple methods including non-participant observation, interviews, and document analysis through an iterative analysis process. The initial propositions (conjectured CMOs) only partially corresponded to the findings that emerged during analysis. From the iterative analysis process of scrutinising mechanisms, context, and outcomes we were able to draw out some theoretically generalisable features about what works, for whom, how, and what circumstances in relation to the use of standardised care approaches (refined CMOs). Conclusions As one of the first studies to apply realistic evaluation in implementation research, it was a good fit, particularly given the growing emphasis on

  17. Biophysically realistic filament bending dynamics in agent-based biological simulation.

    Directory of Open Access Journals (Sweden)

    Jonathan B Alberts

    Full Text Available An appealing tool for study of the complex biological behaviors that can emerge from networks of simple molecular interactions is an agent-based, computational simulation that explicitly tracks small-scale local interactions--following thousands to millions of states through time. For many critical cell processes (e.g. cytokinetic furrow specification, nuclear centration, cytokinesis, the flexible nature of cytoskeletal filaments is likely to be critical. Any computer model that hopes to explain the complex emergent behaviors in these processes therefore needs to encode filament flexibility in a realistic manner. Here I present a numerically convenient and biophysically realistic method for modeling cytoskeletal filament flexibility in silico. Each cytoskeletal filament is represented by a series of rigid segments linked end-to-end in series with a variable attachment point for the translational elastic element. This connection scheme allows an empirically tuning, for a wide range of segment sizes, viscosities, and time-steps, that endows any filament species with the experimentally observed (or theoretically expected static force deflection, relaxation time-constant, and thermal writhing motions. I additionally employ a unique pair of elastic elements--one representing the axial and the other the bending rigidity- that formulate the restoring force in terms of single time-step constraint resolution. This method is highly local -adjacent rigid segments of a filament only interact with one another through constraint forces-and is thus well-suited to simulations in which arbitrary additional forces (e.g. those representing interactions of a filament with other bodies or cross-links / entanglements between filaments may be present. Implementation in code is straightforward; Java source code is available at www.celldynamics.org.

  18. On Formal vs. Realistic Right of Exit and Voice

    OpenAIRE

    Hyyrynen (Isopoussu), Milla-Maria

    2011-01-01

    In my Master's thesis I discuss a relatively new topic in the discussion on multiculturalism in political philosophy, the right of exit from a religious or a cultural group. Liberal theorists agree on the fact that everyone should be free to leave their group, to have a right to exit. However, they disagree on the content of the right. I present two schools on the topic: the formal right of exit strategy by Chandran Kukathas and the realistic right of exit strategy by Susan Moller Okin. ...

  19. Ultra-Reliable Communications in Failure-Prone Realistic Networks

    DEFF Research Database (Denmark)

    Gerardino, Guillermo Andrés Pocovi; Lauridsen, Mads; Alvarez, Beatriz Soret

    2016-01-01

    We investigate the potential of different diversity and interference management techniques to achieve the required downlink SINR outage probability for ultra-reliable communications. The evaluation is performed in a realistic network deployment based on site-specific data from a European capital....... Micro and macroscopic diversity techniques are proved to be important enablers of ultra-reliable communications. Particularly, it is shown how a 4x4 MIMO scheme with three orders of macroscopic diversity can achieve the required SINR outage performance. Smaller gains are obtained from interference...

  20. ROC Analysis and a Realistic Model of Heart Rate Variability

    CERN Document Server

    Thurner, S; Teich, M C; Thurner, Stefan; Feurstein, Markus C.; Teich, Malvin C.

    1998-01-01

    We have carried out a pilot study on a standard collection of electrocardiograms from patients who suffer from congestive heart failure, and subjects without cardiac pathology, using receiver-operating-characteristic (ROC) analysis. The scale-dependent wavelet-coefficient standard deviation superior to two commonly used measures of cardiac dysfunction when the two classes of patients cannot be completely separated. A jittered integrate-and-fire model with a fractal Gaussian-noise kernel provides a realistic simulation of heartbeat sequences for both heart-failure patients and normal subjects.

  1. Centralized Cooperative Positioning and Tracking with Realistic Communications Constraints

    DEFF Research Database (Denmark)

    Mensing, Christian; Nielsen, Jimmy Jessen

    2010-01-01

    In this paper, we investigate the performance of centralized cooperative positioning algorithms. Compared to traditional positioning algorithms which solely exploit ranging information from anchor nodes, cooperative positioning additionally uses measurements from peer-to-peer links between...... on the overall performance will be assessed. As we are considering a dynamic scenario, the cooperative positioning algorithms are based on extended Kalman filtering for position estimation and tracking. Simulation results for ultra-wideband based ranging information and WLAN based communications infrastructure...... show the benefits of cooperative position and tracking for realistic measurement and mobility models....

  2. Black holes in realistic branes: Black string-like objects?

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D., E-mail: bazeia@fisica.ufpb.br [Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP (Brazil); Departamento de Física, Universidade Federal da Paraíba, 58051-970, João Pessoa, PB (Brazil); Hoff da Silva, J.M., E-mail: hoff@feg.unesp.br [Departamento de Física e Química, Universidade Estadual Paulista, Av. Dr. Ariberto Pereira da Cunha, 333, Guaratinguetá, SP (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC (UFABC), 09210-170, Santo André, SP (Brazil)

    2013-04-25

    A realistic model describing a black string-like object in an expanding Universe is analyzed in the context of the McVittie's solution of the Einstein field equations. The bulk metric near the brane is provided analogously to previous solutions for black strings. In particular, we show that at least when the Hubble parameter on the brane is positive, a black string-like object seems to play a fundamental role in the braneworld scenario, generalizing the standard black strings in the context of a dynamical brane.

  3. Scalarization of neutron stars with realistic equations of state

    Science.gov (United States)

    Altaha Motahar, Zahra; Blázquez-Salcedo, Jose Luis; Kleihaus, Burkhard; Kunz, Jutta

    2017-09-01

    We consider the effect of scalarization on static and slowly rotating neutron stars for a wide variety of realistic equations of state, including pure nuclear matter, nuclear matter with hyperons, hybrid nuclear and quark matter, and pure quark matter. We analyze the onset of scalarization, presenting a universal relation for the critical coupling parameter versus compactness. We find that the onset and the magnitude of the scalarization are strongly correlated with the value of the gravitational potential (the metric component gt t) at the center of the star. We also consider the moment-of-inertia-compactness relations and confirm universality for the nuclear matter, hyperon and hybrid equations of state.

  4. [A new age of mass casuality education? : The InSitu project: realistic training in virtual reality environments].

    Science.gov (United States)

    Lorenz, D; Armbruster, W; Vogelgesang, C; Hoffmann, H; Pattar, A; Schmidt, D; Volk, T; Kubulus, D

    2016-09-01

    Chief emergency physicians are regarded as an important element in the care of the injured and sick following mass casualty accidents. Their education is very theoretical; practical content in contrast often falls short. Limitations are usually the very high costs of realistic (large-scale) exercises, poor reproducibility of the scenarios, and poor corresponding results. To substantially improve the educational level because of the complexity of mass casualty accidents, modified training concepts are required that teach the not only the theoretical but above all the practical skills considerably more intensively than at present. Modern training concepts should make it possible for the learner to realistically simulate decision processes. This article examines how interactive virtual environments are applicable for the education of emergency personnel and how they could be designed. Virtual simulation and training environments offer the possibility of simulating complex situations in an adequately realistic manner. The so-called virtual reality (VR) used in this context is an interface technology that enables free interaction in addition to a stereoscopic and spatial representation of virtual large-scale emergencies in a virtual environment. Variables in scenarios such as the weather, the number wounded, and the availability of resources, can be changed at any time. The trainees are able to practice the procedures in many virtual accident scenes and act them out repeatedly, thereby testing the different variants. With the aid of the "InSitu" project, it is possible to train in a virtual reality with realistically reproduced accident situations. These integrated, interactive training environments can depict very complex situations on a scale of 1:1. Because of the highly developed interactivity, the trainees can feel as if they are a direct part of the accident scene and therefore identify much more with the virtual world than is possible with desktop systems

  5. Simulating realistic predator signatures in quantitative fatty acid signature analysis

    Science.gov (United States)

    Bromaghin, Jeffrey F.

    2015-01-01

    Diet estimation is an important field within quantitative ecology, providing critical insights into many aspects of ecology and community dynamics. Quantitative fatty acid signature analysis (QFASA) is a prominent method of diet estimation, particularly for marine mammal and bird species. Investigators using QFASA commonly use computer simulation to evaluate statistical characteristics of diet estimators for the populations they study. Similar computer simulations have been used to explore and compare the performance of different variations of the original QFASA diet estimator. In both cases, computer simulations involve bootstrap sampling prey signature data to construct pseudo-predator signatures with known properties. However, bootstrap sample sizes have been selected arbitrarily and pseudo-predator signatures therefore may not have realistic properties. I develop an algorithm to objectively establish bootstrap sample sizes that generates pseudo-predator signatures with realistic properties, thereby enhancing the utility of computer simulation for assessing QFASA estimator performance. The algorithm also appears to be computationally efficient, resulting in bootstrap sample sizes that are smaller than those commonly used. I illustrate the algorithm with an example using data from Chukchi Sea polar bears (Ursus maritimus) and their marine mammal prey. The concepts underlying the approach may have value in other areas of quantitative ecology in which bootstrap samples are post-processed prior to their use.

  6. Neural Correlates of Realistic and Unrealistic Auditory Space Perception

    Directory of Open Access Journals (Sweden)

    Akiko Callan

    2011-10-01

    Full Text Available Binaural recordings can simulate externalized auditory space perception over headphones. However, if the orientation of the recorder's head and the orientation of the listener's head are incongruent, the simulated auditory space is not realistic. For example, if a person lying flat on a bed listens to an environmental sound that was recorded by microphones inserted in ears of a person who was in an upright position, the sound simulates an auditory space rotated 90 degrees to the real-world horizontal axis. Our question is whether brain activation patterns are different between the unrealistic auditory space (ie, the orientation of the listener's head and the orientation of the recorder's head are incongruent and the realistic auditory space (ie, the orientations are congruent. River sounds that were binaurally recorded either in a supine position or in an upright body position were served as auditory stimuli. During fMRI experiments, participants listen to the stimuli and pressed one of two buttons indicating the direction of the water flow (horizontal/vertical. Behavioral results indicated that participants could not differentiate between the congruent and the incongruent conditions. However, neuroimaging results showed that the congruent condition activated the planum temporale significantly more than the incongruent condition.

  7. Numerical computation of aeroacoustic transfer functions for realistic airfoils

    Science.gov (United States)

    Miotto, Renato Fuzaro; Wolf, William Roberto; de Santana, Leandro Dantas

    2017-10-01

    Based on Amiet's theory formalism, we propose a numerical framework to compute the aeroacoustic transfer function of realistic airfoil geometries. The aeroacoustic transfer function relates the amplitude and phase of an incoming periodic gust to the respective unsteady lift response permitting, therefore, the application of Curle's analogy to compute the radiated noise. The methodology is focused on the airfoil leading-edge noise problem being able to also consider the trailing-edge back-scattering and, consequently, airfoil compactness effects. The approach is valid for compressible subsonic flows and the airfoil blade is assumed of large aspect ratio subjected to three-dimensional periodic gusts with supersonic velocity trace at the airfoil leading edge (i.e. supercritical gusts). This work proposes the iterative application of the boundary element method to numerically solve the boundary value problem prescribed by the linearized airfoil theory. Details of the numerical implementation are discussed and include the application of boundary conditions in different steps of the iterative procedure, treatment of derivatives in the implementation of the Kutta condition and accurate representation of singularities present at the leading- and trailing-edges. This study validates the numerical approach by comparing results with Amiet's theory obtained analytically. Subsequently, effects of realistic airfoil geometries on the leading-edge airfoil radiated noise are presented.

  8. Electron percolation in realistic models of carbon nanotube networks

    Science.gov (United States)

    Simoneau, Louis-Philippe; Villeneuve, Jérémie; Rochefort, Alain

    2015-09-01

    The influence of penetrable and curved carbon nanotubes (CNT) on the charge percolation in three-dimensional disordered CNT networks have been studied with Monte-Carlo simulations. By considering carbon nanotubes as solid objects but where the overlap between their electron cloud can be controlled, we observed that the structural characteristics of networks containing lower aspect ratio CNT are highly sensitive to the degree of penetration between crossed nanotubes. Following our efficient strategy to displace CNT to different positions to create more realistic statistical models, we conclude that the connectivity between objects increases with the hard-core/soft-shell radii ratio. In contrast, the presence of curved CNT in the random networks leads to an increasing percolation threshold and to a decreasing electrical conductivity at saturation. The waviness of CNT decreases the effective distance between the nanotube extremities, hence reducing their connectivity and degrading their electrical properties. We present the results of our simulation in terms of thickness of the CNT network from which simple structural parameters such as the volume fraction or the carbon nanotube density can be accurately evaluated with our more realistic models.

  9. A software assistant for the design of realistic software phantoms

    Science.gov (United States)

    Rexilius, Jan; Konrad, Olaf; Peitgen, Heinz-Otto

    2008-03-01

    Segmentation and quantification of medical image data are difficult problems in image analysis. Especially, an accurate and robust assessment of quantitative parameters is a key issue in many fields, and can have a direct impact on diagnosis and treatment planning. To this end, physical and software phantom data sets have become an integral tool during the design, implementation, and optimization of new algorithms. Unfortunately, a common research resource has not been established until now for many applications. In this work we propose a software assistant for the development of realistic software phantoms. Our aim is an easy-to-use tool with an intuitive user interface. Furthermore, we provide a software for researchers including a common basis of reference data, which facilitates a standardized and objective validation of performance and limitations of own developments, as well as the comparison of different methods. The fundamental phantom design focuses on objects that can be incorporated into a given background. This can either be a homogeneous artificial background, or a volunteer or patient data set. For each phantom the exact ground truth of the investigated object is available, which provides us with an excellent tool for the generation of realistic data sets. Several experiments are carried out for a number of different applications including software phantoms of small, hyperintense brain lesions, as well as software phantoms of liver metastases.

  10. Music therapy for palliative care: A realist review.

    Science.gov (United States)

    McConnell, Tracey; Porter, Sam

    2017-08-01

    Music therapy has experienced a rising demand as an adjunct therapy for symptom management among palliative care patients. We conducted a realist review of the literature to develop a greater understanding of how music therapy might benefit palliative care patients and the contextual mechanisms that promote or inhibit its successful implementation. We searched electronic databases (CINAHL, Embase, Medline, and PsychINFO) for literature containing information on music therapy for palliative care. In keeping with the realist approach, we examined all relevant literature to develop theories that could explain how music therapy works. A total of 51 articles were included in the review. Music therapy was found to have a therapeutic effect on the physical, psychological, emotional, and spiritual suffering of palliative care patients. We also identified program mechanisms that help explain music therapy's therapeutic effects, along with facilitating contexts for implementation. Music therapy may be an effective nonpharmacological approach to managing distressing symptoms in palliative care patients. The findings also suggest that group music therapy may be a cost-efficient and effective way to support staff caring for palliative care patients. We encourage others to continue developing the evidence base in order to expand our understanding of how music therapy works, with the aim of informing and improving the provision of music therapy for palliative care patients.

  11. Validation of a realistic simulator for veterinary gastrointestinal endoscopy training.

    Science.gov (United States)

    Usón-Gargallo, Jesús; Usón-Casaús, Jesús M; Pérez-Merino, Eva M; Soria-Gálvez, Federico; Morcillo, Esther; Enciso, Silvia; Sánchez-Margallo, Francisco M

    2014-01-01

    This article reports on the face, content, and construct validity of a new realistic composite simulator (Simuldog) used to provide training in canine gastrointestinal flexible endoscopy. The basic endoscopic procedures performed on the simulator were esophagogastroduodenoscopy (EGD), gastric biopsy (GB), and gastric foreign body removal (FBR). Construct validity was assessed by comparing the performance of novices (final-year veterinary students and recent graduates without endoscopic experience, n=30) versus experienced subjects (doctors in veterinary medicine who had performed more than 50 clinical upper gastrointestinal endoscopic procedures as a surgeon, n=15). Tasks were scored based on completion time, and specific rating scales were developed to assess performance. Internal consistency and inter-rater agreement were assessed. Face and content validity were determined using a 5-point Likert-type scale questionnaire. The novices needed considerably more time than the experts to perform EGD, GB, and FBR, and their performance scores were significantly lower (pinternal validity of the rating scales were good. Face validity was excellent, and both groups agreed that the endoscopy scenarios were very realistic. The experts highly valued the usefulness of Simuldog for veterinary training and as a tool for assessing endoscopic skills. Simuldog is the first validated model specifically developed to be used as a training tool for endoscopy techniques in small animals.

  12. Fault-Tolerant Robot Programming through Simulation with Realistic Sensor Models

    Directory of Open Access Journals (Sweden)

    Thomas Bräunl

    2006-06-01

    Full Text Available We introduce a simulation system for mobile robots that allows a realistic interaction of multiple robots in a common environment. The simulated robots are closely modeled after robots from the EyeBot family and have an identical application programmer interface. The simulation supports driving commands at two levels of abstraction as well as numerous sensors such as shaft encoders, infrared distance sensors, and compass. Simulation of on-board digital cameras via synthetic images allows the use of image processing routines for robot control within the simulation. Specific error models for actuators, distance sensors, camera sensor, and wireless communication have been implemented. Progressively increasing error levels for an application program allows for testing and improving its robustness and fault-tolerance.

  13. Fault-Tolerant Robot Programming through Simulation with Realistic Sensor Models

    Directory of Open Access Journals (Sweden)

    Axel Waggershauser

    2008-11-01

    Full Text Available We introduce a simulation system for mobile robots that allows a realistic interaction of multiple robots in a common environment. The simulated robots are closely modeled after robots from the EyeBot family and have an identical application programmer interface. The simulation supports driving commands at two levels of abstraction as well as numerous sensors such as shaft encoders, infrared distance sensors, and compass. Simulation of on-board digital cameras via synthetic images allows the use of image processing routines for robot control within the simulation. Specific error models for actuators, distance sensors, camera sensor, and wireless communication have been implemented. Progressively increasing error levels for an application program allows for testing and improving its robustness and fault-tolerance.

  14. Computing the electric field from extensive air showers using a realistic description of the atmosphere

    Science.gov (United States)

    Gaté, F.; Revenu, B.; García-Fernández, D.; Marin, V.; Dallier, R.; Escudié, A.; Martin, L.

    2018-03-01

    The composition of ultra-high energy cosmic rays is still poorly known and constitutes a very important topic in the field of high-energy astrophysics. Detection of ultra-high energy cosmic rays is carried out via the extensive air showers they create after interacting with the atmosphere constituents. The secondary electrons and positrons within the showers emit a detectable electric field in the kHz-GHz range. It is possible to use this radio signal for the estimation of the atmospheric depth of maximal development of the showers Xmax , with a good accuracy and a duty cycle close to 100%. This value of Xmax is strongly correlated to the nature of the primary cosmic ray that initiated the shower. We show in this paper the importance of using a realistic atmospheric model in order to correct for systematic errors that can prevent a correct and unbiased estimation of Xmax.

  15. Dipole response in neutron-rich nuclei within self-consistent approaches using realistic potentials

    Directory of Open Access Journals (Sweden)

    Lo Iudice N.

    2015-01-01

    Full Text Available A nucleon-nucleon chiral potential with a corrective density dependent term simulating a three-body force is used in a self-consistent calculation of the dipole strength distribution in neutron-rich nuclei, with special attention to the low-lying spectra associated to the pygmy resonance. A Hartree-Fock-Bogoliubov basis is generated and adopted in Tamm-Dancoff and random-phase approximations and, then, in an equation of motion approach which includes a basis of two-phonon states. The direct use of the mentioned chiral potential improves the description of both giant and pygmy dipole modes with respect to other realistic interactions. Moreover, the inclusion of the two-phonon states induces a pronounced fragmentation of the giant resonance and enhances the density of the low-lying levels in the pygmy region in agreement with recent experiments.

  16. Involving people with diabetes and the wider community in diabetes research: a realist review protocol.

    Science.gov (United States)

    Harris, Janet; Graue, Marit; Dunning, Trisha; Haltbakk, Johannes; Austrheim, Gunhild; Skille, Nina; Rokne, Berit; Kirkevold, Marit

    2015-11-04

    Patient and public involvement in diabetes research is now actively encouraged in different countries because it is believed that involving people with experience of the condition will improve the quality and relevance of the research. However, reviews of patient involvement have noted that inadequate resources, patients' and communities' lack of research knowledge, and researchers' lack of skills to involve patients and communities in research may present significant contextual barriers. Little is known about the extent of patient/community involvement in designing or delivering interventions for people with diabetes. A realist review of involvement will contribute to assessing when, how and why involvement works, or does not work, to produce better diabetes interventions. This protocol outlines the process for conducting a realist review to map how patients and the public have been involved in diabetes research to date. The review questions ask the following: How have people with diabetes and the wider community been involved in diabetes research? What are the characteristics of the process that appear to explain the relative success or failure of involvement? How has involvement (or lack of involvement) in diabetes research influenced the development and conduct of diabetes research? The degree of support in the surrounding context will be assessed alongside the ways in which people interact in different settings to identify patterns of interaction between context, mechanisms and outcomes in different research projects. The level and extent of the involvement will be described for each stage of the research project. The descriptions will be critically reviewed by the people with diabetes on our review team. In addition, researchers and patients in diabetes research will be asked to comment. Information from researcher-patient experiences and documents will be compared to theories of involvement across a range of disciplines to create a mid-range theory

  17. Neurobiologically realistic determinants of self-organized criticality in networks of spiking neurons.

    Directory of Open Access Journals (Sweden)

    Mikail Rubinov

    2011-06-01

    Full Text Available Self-organized criticality refers to the spontaneous emergence of self-similar dynamics in complex systems poised between order and randomness. The presence of self-organized critical dynamics in the brain is theoretically appealing and is supported by recent neurophysiological studies. Despite this, the neurobiological determinants of these dynamics have not been previously sought. Here, we systematically examined the influence of such determinants in hierarchically modular networks of leaky integrate-and-fire neurons with spike-timing-dependent synaptic plasticity and axonal conduction delays. We characterized emergent dynamics in our networks by distributions of active neuronal ensemble modules (neuronal avalanches and rigorously assessed these distributions for power-law scaling. We found that spike-timing-dependent synaptic plasticity enabled a rapid phase transition from random subcritical dynamics to ordered supercritical dynamics. Importantly, modular connectivity and low wiring cost broadened this transition, and enabled a regime indicative of self-organized criticality. The regime only occurred when modular connectivity, low wiring cost and synaptic plasticity were simultaneously present, and the regime was most evident when between-module connection density scaled as a power-law. The regime was robust to variations in other neurobiologically relevant parameters and favored systems with low external drive and strong internal interactions. Increases in system size and connectivity facilitated internal interactions, permitting reductions in external drive and facilitating convergence of postsynaptic-response magnitude and synaptic-plasticity learning rate parameter values towards neurobiologically realistic levels. We hence infer a novel association between self-organized critical neuronal dynamics and several neurobiologically realistic features of structural connectivity. The central role of these features in our model may reflect

  18. From Minimal to Realistic Supersymmetric SU(5) Grand Unification

    CERN Document Server

    Altarelli, Guido; Masina, I; Altarelli, Guido; Feruglio, Ferruccio; Masina, Isabella

    2000-01-01

    We construct and discuss a "realistic" example of SUSY SU(5) GUT model, with an additional U(1) flavour symmetry, that is not plagued by the need of large fine tunings, like those associated with doublet-triplet splitting in the minimal model, and that leads to an acceptable phenomenology. This includes coupling unification with a value of alpha_s(m_Z) in much better agreement with the data than in the minimal version, an acceptable hierarchical pattern for fermion masses and mixing angles, also including neutrino masses and mixings, and a proton decay rate compatible with present limits (but the discovery of proton decay should be within reach of the next generation of experiments). In the neutrino sector the preferred solution is one with nearly maximal mixing both for atmospheric and solar neutrinos.

  19. Magnetic exchange at realistic CoO/Ni interfaces

    Science.gov (United States)

    Grytsyuk, S.; Cossu, F.; Schwingenschlögl, U.

    2012-08-01

    We study the CoO/Ni interface by first principles calculations. Because the lattice mismatch is large, a realistic description requires a huge supercell. We investigate two interface configurations: in interface 1 the coupling between the Ni and Co atoms is mediated by O, whereas in interface 2 the Ni and Co atoms are in direct contact. We find that the magnetization (including the orbital moment) in interface 1 has a similar value as in bulk Ni but opposite sign, while in interface 2 it grows by 164%. The obtained magnetic moments can be explained by the local atomic environments. In addition, we find effects of charge transfer between the interface atoms. The Co 3 d local density of states of interface 2 exhibits surprisingly small deviations from the corresponding bulk result, although the first coordination sphere is no longer octahedral.

  20. Dynamic Enhanced Inter-Cell Interference Coordination for Realistic Networks

    DEFF Research Database (Denmark)

    Pedersen, Klaus I.; Alvarez, Beatriz Soret; Barcos, Sonia

    2016-01-01

    ICIC configuration leads to modest gains, whereas the set of proposed fast dynamic eICIC algorithms result in capacity gains on the order of 35-120% depending on the local environment characteristics. These attractive gains together with the simplicity of the proposed solutions underline the practical relevance...... area. Rather than the classical semi-static and network-wise configuration, the importance of having highly dynamic and distributed mechanisms that are able to adapt to local environment conditions is revealed. We propose two promising cell association algorithms: one aiming at pure load balancing...... and an opportunistic approach exploiting the varying cell conditions. Moreover, an autonomous fast distributed muting algorithm is presented, which is simple, robust, and well suited for irregular network deployments. Performance results for realistic network deployments show that the traditional semi-static e...

  1. Simulating realistic implementations of spin field effect transistor

    Science.gov (United States)

    Gao, Yunfei; Lundstrom, Mark S.; Nikonov, Dmitri E.

    2011-04-01

    The spin field effect transistor (spinFET), consisting of two ferromagnetic source/drain contacts and a Si channel, is predicted to have outstanding device and circuit performance. We carry out a rigorous numerical simulation of the spinFET based on the nonequilibrium Green's function formalism self-consistently coupled with a Poisson solver to produce the device I-V characteristics. Good agreement with the recent experiments in terms of spin injection, spin transport, and the magnetoresistance ratio (MR) is obtained. We include factors crucial for realistic devices: tunneling through a dielectric barrier, and spin relaxation at the interface and in the channel. Using these simulations, we suggest ways of optimizing the device. We propose that by choosing the right contact material and inserting tunnel oxide barriers between the source/drain and channel to filter different spins, the MR can be restored to ˜2000%, which would be beneficial to the reconfigurable logic circuit application.

  2. Towards realistic string vacua from branes at singularities

    CERN Document Server

    Conlon, Joseph P; Quevedo, Fernando

    2009-01-01

    We report on progress towards constructing string models incorporating both realistic D-brane matter content and full moduli stabilisation with dynamical low-scale supersymmetry breaking. The general framework is that of local D-brane models embedded into the LARGE volume approach to moduli stabilisation. We review quiver theories on del Pezzo n (dP_n) singularities including both D3 and D7 branes. We provide supersymmetric examples with three quark/lepton families and the gauge symmetries of the Standard, Left-Right Symmetric, Pati-Salam and Trinification models, without unwanted chiral exotics. We describe how the singularity structure leads to family symmetries governing the Yukawa couplings which can give mass hierarchies among the different generations. We outline how these models can be embedded into compact Calabi-Yau compactifications with LARGE volume moduli stabilisation, and state the minimal conditions for this to be possible. We study the general structure of soft supersymmetry breaking. At the s...

  3. Tool for Generating Realistic Residential Hot Water Event Schedules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Hendron, B.; Burch, J.; Barker, G.

    2010-08-01

    The installed energy savings for advanced residential hot water systems can depend greatly on detailed occupant use patterns. Quantifying these patterns is essential for analyzing measures such as tankless water heaters, solar hot water systems with demand-side heat exchangers, distribution system improvements, and recirculation loops. This paper describes the development of an advanced spreadsheet tool that can generate a series of year-long hot water event schedules consistent with realistic probability distributions of start time, duration and flow rate variability, clustering, fixture assignment, vacation periods, and seasonality. This paper also presents the application of the hot water event schedules in the context of an integral-collector-storage solar water heating system in a moderate climate.

  4. Atomistic Simulation of Polymer Crystallization at Realistic Length Scales

    Energy Technology Data Exchange (ETDEWEB)

    Gee, R H; Fried, L E

    2005-01-28

    Understanding the dynamics of polymer crystallization during the induction period prior to crystal growth is a key goal in polymer physics. Here we present the first study of primary crystallization of polymer melts via molecular dynamics simulations at physically realistic (about 46 nm) length scales. Our results show that the crystallization mechanism involves a spinodal decomposition microphase separation caused by an increase in the average length of rigid trans segments along the polymer backbone during the induction period. Further, the characteristic length of the growing dense domains during the induction period is longer than predicted by classical nucleation theory. These results indicate a new 'coexistence period' in the crystallization, where nucleation and growth mechanisms coexist with a phase separation mechanism. Our results provide an atomistic verification of the fringed micelle model.

  5. Magnetic exchange at realistic CoO/Ni interfaces

    KAUST Repository

    Grytsiuk, Sergii

    2012-07-30

    We study the CoO/Ni interface by first principles calculations. Because the lattice mismatch is large, a realistic description requires a huge supercell. We investigate two interface configurations: in interface 1 the coupling between the Ni and Co atoms is mediated by O, whereas in interface 2 the Ni and Co atoms are in direct contact. We find that the magnetization (including the orbital moment) in interface 1 has a similar value as in bulk Ni but opposite sign, while in interface 2 it grows by 164%. The obtained magnetic moments can be explained by the local atomic environments. In addition, we find effects of charge transfer between the interface atoms. The Co 3d local density of states of interface 2 exhibits surprisingly small deviations from the corresponding bulk result, although the first coordination sphere is no longer octahedral. © Springer-Verlag 2012.

  6. Realistic prediction of dynamic aperture and optics performance for LEP

    CERN Document Server

    Jowett, John M

    1999-01-01

    Over the two-decade lifetime of the LEP project, techniques for evaluating the quality of optical configurations have evolved considerably to exploit the growth in computer power and improved modelling of single-particle dynamics. These developments have culminated in a highly automated Monte-Carlo evaluation process whose stages include the generation of an ensemble of imperfect machines, simulation of the operational correction procedures, correlation studies of the optical functions and parameters of (both) beams, 4-dimensional dynamic aperture scans and tracking with quantum fluctuations to determine the beam core distribution. We outline the process, with examples, and explain why each step is necessary to realistically capture essential physics affecting performance. The mechanisms determining the vertical emittance, radial beam distribution and dynamic aperture are especially important. As a storage ring in which an unusual variety of optics have been tested, LEP provides a valuable test case for the p...

  7. Finite Time Blowup in a Realistic Food-Chain Model

    KAUST Repository

    Parshad, Rana

    2013-05-19

    We investigate a realistic three-species food-chain model, with generalist top predator. The model based on a modified version of the Leslie-Gower scheme incorporates mutual interference in all the three populations and generalizes several other known models in the ecological literature. We show that the model exhibits finite time blowup in certain parameter range and for large enough initial data. This result implies that finite time blowup is possible in a large class of such three-species food-chain models. We propose a modification to the model and prove that the modified model has globally existing classical solutions, as well as a global attractor. We reconstruct the attractor using nonlinear time series analysis and show that it pssesses rich dynamics, including chaos in certain parameter regime, whilst avoiding blowup in any parameter regime. We also provide estimates on its fractal dimension as well as provide numerical simulations to visualise the spatiotemporal chaos.

  8. Realistic finite temperature simulations of magnetic systems using quantum statistics

    Science.gov (United States)

    Bergqvist, Lars; Bergman, Anders

    2018-01-01

    We have performed realistic atomistic simulations at finite temperatures using Monte Carlo and atomistic spin dynamics simulations incorporating quantum (Bose-Einstein) statistics. The description is much improved at low temperatures compared to classical (Boltzmann) statistics normally used in these kind of simulations, while at higher temperatures the classical statistics are recovered. This corrected low-temperature description is reflected in both magnetization and the magnetic specific heat, the latter allowing for improved modeling of the magnetic contribution to free energies. A central property in the method is the magnon density of states at finite temperatures, and we have compared several different implementations for obtaining it. The method has no restrictions regarding chemical and magnetic order of the considered materials. This is demonstrated by applying the method to elemental ferromagnetic systems, including Fe and Ni, as well as Fe-Co random alloys and the ferrimagnetic system GdFe3.

  9. Radioactive waste management in Brazil: a realistic view

    Energy Technology Data Exchange (ETDEWEB)

    Heilbron Filho, Paulo Fernando Lavalle; Perez Guerrero, Jesus Salvador, E-mail: paulo@cnen.gov.br, E-mail: jperez@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Xavier, Ana Maria, E-mail: axavier@cnen.gov.br [Comissao Nacional de Energia Nuclear (ESPOA/CNEN-RS), Porto Alegre, RS (Brazil)

    2014-07-01

    The objective of this article is to present a realistic view of the main issues related to the management of radioactive waste in Brazil as well as a comprehensive picture of the regulatory waste management status in the country and internationally. Technical aspects that must be considered to ensure a safe construction of near surface disposal facilities for radioactive waste of low and medium levels of radiation are addressed. Different types of deposits, the basic regulatory issues involving the licensing of these facilities, the development of a financial compensation model for the Brazilian Municipalities where deposits are to be placed, the importance of the participation of the scientific community and society in the process of radioactive waste site selection and disposal, guidance for the application of the basic requirements of safety and radiation protection, the general safety aspects involved and the current actions for the disposal of radioactive waste in Brazil are highlighted. (author)

  10. On Realistic Brane Worlds from Type i Strings

    Science.gov (United States)

    Aldazabal, Gerardo; IbÁñez, Luis E.; Quevedo, Fernando

    We review recent progress in constructing realistic brane models from type I string vacua. Explicit models with three families of the standard model gauge group and its l-right generalizations are presented with supersymmetry broken at the string scale of order Ms ~ 1010-12 roman>GeVroman>, realizing gravity mediated supersymmetry breaking at low energies. Unification of couplings occurs at the string scale due to the particular U(1) normalizations of roman>Droman>-branes, as well as to the existence of a Higgs field per family of quarks and leptons. The proton is naturally stable due to intrinsic discrete symmetries of the corresponding string theory. In particular R-parity appears as a natural stringy symmetry. There are axionic fields with the right couplings as to solve the strong CP problem. Similar realizations are also presented for a string scale of 1 TeV, although without solving the gauge unification problem. Open questions are briefly discussed.

  11. Multiparameter quantum metrology of incoherent point sources: Towards realistic superresolution

    Science.gov (United States)

    Řehaček, J.; Hradil, Z.; Stoklasa, B.; Paúr, M.; Grover, J.; Krzic, A.; Sánchez-Soto, L. L.

    2017-12-01

    We establish the multiparameter quantum Cramér-Rao bound for simultaneously estimating the centroid, the separation, and the relative intensities of two incoherent optical point sources using a linear imaging system. For equally bright sources, the Cramér-Rao bound is independent of their separation, which confirms that the Rayleigh resolution limit is just an artifact of the conventional direct imaging and can be overcome with an adequate strategy. For the general case of unequally bright sources, the amount of information one can gain about the separation falls to zero, but we show that there is always a quadratic improvement in an optimal detection in comparison with the intensity measurements. This advantage can be of utmost importance in realistic scenarios, such as observational astronomy.

  12. Realistically Rendering SoC Traffic Patterns with Interrupt Awareness

    DEFF Research Database (Denmark)

    Angiolini, Frederico; Mahadevan, Sharkar; Madsen, Jan

    2005-01-01

    In Multi-Processor System-on-Chip (MPSoC) design stages, accurate modeling of IP behaviour is crucial to analyze interconnect effectiveness. However, parallel development of components may cause IP core models to be still unavailable when tuning communication performance. Traditionally, synthetic...... traffic generators have been used to overcome such an issue. However, target applications increasingly present non-trivial execution flows and synchronization patterns, especially in presence of underlying operating systems and when exploiting interrupt facilities. This property makes it very difficult...... to generate realistic test traffic. This paper presents a selection of applications using interrupt-based synchronization; a reference methodology to split such applications in execution subflows and to adjust the overall execution stream based upon hardware events; a reactive simulation device capable...

  13. Air-Flow Simulation in Realistic Models of the Trachea

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, T; Schwartz, P; Trebotich, D

    2004-12-09

    In this article we present preliminary results from a new technique for flow simulation in realistic anatomical airways. The airways are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of anatomical objects. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier- Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element gridding of the whole volume, our method directly simulates the air-flow inside the extracted surface without losing any complicated details and without building additional grids.

  14. Capturing and reproducing realistic acoustic scenes for hearing research

    DEFF Research Database (Denmark)

    Marschall, Marton; Buchholz, Jörg

    Accurate spatial audio recordings are important for a range of applications, from the creation of realistic virtual sound environments to the evaluation of communication devices, such as hearing instruments and mobile phones. Spherical microphone arrays are particularly well-suited for capturing...... spatial audio in three dimensions. However, practical constraints limit the number of microphones that can be used and thus the maximum spatial resolution and frequency bandwidth that can be achieved. Further, most important sound sources are near the horizontal plane, where human spatial hearing is also...... most accurate. This thesis therefore investigated whether the horizontal performance of spherical microphone arrays could be improved (i) through an appropriate placement of a fixed number of transducers on the sphere, and (ii) by applying mixed-order ambisonics (MOA) processing. MOA combines higher...

  15. Towards a realistic population of simulated galaxy groups and clusters

    Science.gov (United States)

    Le Brun, Amandine M. C.; McCarthy, Ian G.; Schaye, Joop; Ponman, Trevor J.

    2014-06-01

    We present a new suite of large-volume cosmological hydrodynamical simulations called cosmo-OWLS. They form an extension to the OverWhelmingly Large Simulations (OWLS) project, and have been designed to help improve our understanding of cluster astrophysics and non-linear structure formation, which are now the limiting systematic errors when using clusters as cosmological probes. Starting from identical initial conditions in either the Planck or WMAP7 cosmologies, we systematically vary the most important `sub-grid' physics, including feedback from supernovae and active galactic nuclei (AGN). We compare the properties of the simulated galaxy groups and clusters to a wide range of observational data, such as X-ray luminosity and temperature, gas mass fractions, entropy and density profiles, Sunyaev-Zel'dovich flux, I-band mass-to-light ratio, dominance of the brightest cluster galaxy and central massive black hole (BH) masses, by producing synthetic observations and mimicking observational analysis techniques. These comparisons demonstrate that some AGN feedback models can produce a realistic population of galaxy groups and clusters, broadly reproducing both the median trend and, for the first time, the scatter in physical properties over approximately two decades in mass (1013 M⊙ ≲ M500 ≲ 1015 M⊙) and 1.5 decades in radius (0.05 ≲ r/r500 ≲ 1.5). However, in other models, the AGN feedback is too violent (even though they reproduce the observed BH scaling relations), implying that calibration of the models is required. The production of realistic populations of simulated groups and clusters, as well as models that bracket the observations, opens the door to the creation of synthetic surveys for assisting the astrophysical and cosmological interpretation of cluster surveys, as well as quantifying the impact of selection effects.

  16. Percolation dans des reseaux realistes de nanostructures de carbone

    Science.gov (United States)

    Simoneau, Louis-Philippe

    Carbon nanotubes have very interesting mechanical and electrical properties for various applications in electronics. They are highly resistant to deformation and can be excellent conductors or semiconductors. However, manipulating individual nanotubes to build structured devices remains very difficult. There is no method for controlling all of the electrical properties, the orientation and the spatial positioning of a large number of nanotubes. The fabrication of disordered networks of nanotubes is much easier, and these systems have a good electrical conductivity which makes them very interesting, especially as materials of transparent and flexible electrodes. There are three main methods of production used to make networks of nanotubes: the solution deposition, the direct growth on substrate and the embedding in a polymer matrix. The solution deposition method can form networks of various densities on a variety of substrates, the direct growth of nanotubes allows the creation of very clean networks on substrates such as SiO2, and the embedding in a polymer matrix can give composite volumes containing varying amounts of nanotubes. Many parameters such as the length of the tubes, their orientation or their tortuosity influence the properties of these networks and the presence of structural disorder complicates the understanding of their interactions. Predicting the properties of a network, such as conductivity, from a few characteristics such as size and density of the tubes can be difficult. This task becomes even more complex if one wants to identify the parameters that will optimize the performance of a device containing the material. We chose to address the carbon nanotube networks problem by developing a series of computer simulation tools that are mainly based on the Monte Carlo method. We take into account a large number of parameters to describe the characteristics of the networks, which allows for a more reliable representation of real networks as well as

  17. Neutrino Spectra from Nuclear Weak Interactions in sd-Shell Nuclei under Astrophysical Conditions

    Science.gov (United States)

    Misch, G. Wendell; Sun, Yang; Fuller, George M.

    2018-01-01

    We present shell model calculations of nuclear neutrino energy spectra for 70 sd-shell nuclei over the mass number range A = 21–35. Our calculations include nuclear excited states as appropriate for the hot and dense conditions characteristic of pre-collapse massive stars. We consider neutrinos produced by charged lepton captures and decays, and for the first time in tabular form, neutral current nuclear deexcitation, providing neutrino energy spectra on the Fuller–Fowler–Newman temperature–density grid for these interaction channels for each nucleus. We use the full sd-shell model space to compute initial nuclear states up to 20 MeV excitation with transitions to final states up to 35–40 MeV, employing a modification of the Brink-Axel hypothesis to handle high-temperature population factors and the nuclear partition functions.

  18. Modeling the Normal and Neoplastic Cell Cycle with 'Realistic Boolean Genetic Networks': Their Application for Understanding Carcinogenesis and Assessing Therapeutic Strategies

    Science.gov (United States)

    Szallasi, Zoltan; Liang, Shoudan

    2000-01-01

    In this paper we show how Boolean genetic networks could be used to address complex problems in cancer biology. First, we describe a general strategy to generate Boolean genetic networks that incorporate all relevant biochemical and physiological parameters and cover all of their regulatory interactions in a deterministic manner. Second, we introduce 'realistic Boolean genetic networks' that produce time series measurements very similar to those detected in actual biological systems. Third, we outline a series of essential questions related to cancer biology and cancer therapy that could be addressed by the use of 'realistic Boolean genetic network' modeling.

  19. 3D Realistic Modeling of the Interaction of Quiet-Sun Magnetic Fields with the Chromosphere

    Science.gov (United States)

    Kitiashvili, I. N.; Kosovichev, A. G.; Mansour, N. N.; Wray, A. A.

    2017-01-01

    High-resolution observations and 3D simulations suggest that a local dynamo operates near the surface and produces ubiquitous small-scale magnetic elements, thus contributing to the magnetic carpet in the photosphere and to the magnetic structure and dynamics of the solar atmosphere. It appears that the traditional mechanisms of chromospheric energy and mass transport by acoustic waves and shocks are likely to play a secondary role; instead, the primary drivers in the energetics and dynamics of the chromosphere and transition region are small-scale, previously unresolved, quiet-Sun magnetic fields. These fields appear as ubiquitous, rapidly changing (on the scale of a few seconds), tiny magnetic loops and magnetized vortex tubes. Questions then arise about their origin and dynamics in the chromosphere, their links to magnetic fields in the photosphere, and their role in the energy storage and exchange between subsurface layers and the chromosphere. In the talk we will present results of 3D radiative MHD simulations obtained with the StellarBox code and discuss the energetics and dynamical interlinks between the subphotospheric layers and low chromosphere, their effects on the structure of the chromosphere, and signatures of the fine-scale magnetic features in high-resolution spectro-polarimetric observations.

  20. Middletown 2010 -- A Realistic Interactive Emergency Simulation and Response System for the US Army

    Science.gov (United States)

    2006-12-01

    now a leading digital animation studio with creative, technical and production capabilities to deliver a new generation of 3D animated feature films ...airborne laser scanning emerges as an interesting alternative, photogrammetry based on aerial images remains a key technology for 3D cartography in...have had in-depth discussions on this topic with experts at the Institute of Photogrammetry , University of Bonn, and at the Ecole Nationale Supérieure

  1. Parent education interventions designed to support the transition to parenthood: A realist review.

    Science.gov (United States)

    Gilmer, Cyndi; Buchan, Judy L; Letourneau, Nicole; Bennett, Claudine T; Shanker, Stuart G; Fenwick, Anne; Smith-Chant, Brenda

    2016-07-01

    Public health nurses use parent education programmes to support individuals' transition to parenthood. A wide array of these programmes exists; however, the approach must be accommodated by resources available in a publicly funded system. For example, some new-parent education approaches use 1:1 home visiting (with a nurse or trained lay-home visitor) but the costs of this intensive approach can be prohibitive. Because of this limitation there is an interest in identifying effective and efficient new parent educational approaches that can realistically be provided at a universal level. Unfortunately, there is a lack of high-quality evaluation identifying programmes or educational processes that meet these criteria. To identify potentially effective new-parenting education interventions that could be implemented at a population level during the transition to parenthood period. Realist synthesis. Medline, CINAHL, ERIC, PsycINFO, Sociological Abstracts, grey literature. A realist review method generated a total of 72 papers that were used to inform the results. A three-pronged approach was used incorporating an initial search (6), a database search using applicable keywords and MeSH headings (58), and review of literature identified by advisory group (8 grey literature). An 'implementation chain' was developed to outline the overall logic and process behind parent education interventions and to guide the analysis. Seventy-two papers informed this review: 13 systematic reviews/meta-analyses, 34 intervention studies, 9 opinion papers, 8 programme reviews, and 8 grey literature reports. There was no compelling evidence to suggest that a single educational programme or delivery format was effective at a universal level. Some inherent issues were identified. For example, adult learning principles were overlooked and theories of parent-child interaction were not in evidence. No direct links between universal new-parent education programmes and child development outcomes

  2. Using technology to engage hospitalised patients in their care: a realist review.

    Science.gov (United States)

    Roberts, Shelley; Chaboyer, Wendy; Gonzalez, Ruben; Marshall, Andrea

    2017-06-06

    Patient participation in health care is associated with improved outcomes for patients and hospitals. New technologies are creating vast potential for patients to participate in care at the bedside. Several studies have explored patient use, satisfaction and perceptions of health information technology (HIT) interventions in hospital. Understanding what works for whom, under what conditions, is important when considering interventions successfully engaging patients in care. This realist review aimed to determine key features of interventions using bedside technology to engage hospital patients in their care and analyse these in terms of context, mechanisms and outcomes. A realist review was chosen to explain how and why complex HIT interventions work or fail within certain contexts. The review was guided by Pawson's realist review methodology, involving: clarifying review scope; searching for evidence; data extraction and evidence appraisal; synthesising evidence and drawing conclusions. Author experience and an initial literature scope provided insight and review questions and theories (propositions) around why interventions worked were developed and iteratively refined. A purposive search was conducted to find evidence to support, refute or identify further propositions, which formed an explanatory model. Each study was 'mined' for evidence to further develop the propositions and model. Interactive learning was the overarching theme of studies using technology to engage patients in their care. Several propositions underpinned this, which were labelled: information sharing; self-assessment and feedback; tailored education; user-centred design; and support in use of HIT. As studies were mostly feasibility or usability studies, they reported patient-centred outcomes including patient acceptability, satisfaction and actual use of HIT interventions. For each proposition, outcomes were proposed to come about by mechanisms including improved communication, shared

  3. Exploring why quality circles work in primary health care: a realist review protocol.

    Science.gov (United States)

    Rohrbasser, Adrian; Mickan, Sharon; Harris, Janet

    2013-12-09

    Quality circles (QCs) are commonly used in primary health care in Europe to consider and improve standard practice over time. They represent a complex social intervention that occurs within the fast-changing system of primary health care. Numerous controlled trials, reviews, and studies have shown small but unpredictable positive effect sizes on behavior change. Although QCs seem to be effective, stakeholders have difficulty understanding how the results are achieved and in generalizing the results with confidence. They also lack understanding of the active components of QCs which result in changes in the behavior of health care professionals. This protocol for a realist synthesis will examine how configurations of components and the contextual features of QCs influence their performance. Stakeholder interviews and a scoping search revealed the processes of QCs and helped to describe their core components and underlying theories. After clarifying their historical and geographical distribution, a purposive and systematic search was developed to identify relevant papers to answer the research questions, which are: understanding why, how, and when QCs work, over what time frame, and in what circumstances. After selecting and abstracting appropriate data, configurations of contexts and mechanisms which influence the outcome of QCs within each study will be identified. Studies will be grouped by similar propositional statements in order to identify patterns and validation from stakeholders sought. Finally, theories will be explored in order to explain these patterns and to help stakeholders maintain and improve QC performance. Analyzing context-mechanism-outcome (CMO) patterns will reveal how QCs work and how contextual factors interact to influence their outcome. The aim is to investigate unique configurations that enable them to improve the performance of health care professionals. Using a standardized reporting system, this realist review will allow the research

  4. The NetVISA automatic association tool. Next generation software testing and performance under realistic conditions.

    Science.gov (United States)

    Le Bras, Ronan; Arora, Nimar; Kushida, Noriyuki; Tomuta, Elena; Kebede, Fekadu; Feitio, Paulino

    2016-04-01

    The CTBTO's International Data Centre is in the process of developing the next generation software to perform the automatic association step. The NetVISA software uses a Bayesian approach with a forward physical model using probabilistic representations of the propagation, station capabilities, background seismicity, noise detection statistics, and coda phase statistics. The software has been in development for a few years and is now reaching the stage where it is being tested in a realistic operational context. An interactive module has been developed where the NetVISA automatic events that are in addition to the Global Association (GA) results are presented to the analysts. We report on a series of tests where the results are examined and evaluated by seasoned analysts. Consistent with the statistics previously reported (Arora et al., 2013), the first test shows that the software is able to enhance analysis work by providing additional event hypothesis for consideration by analysts. A test on a three-day data set was performed and showed that the system found 42 additional real events out of 116 examined, including 6 that pass the criterion for the Reviewed Event Bulletin of the IDC. The software was functional in a realistic, real-time mode, during the occurrence of the fourth nuclear test claimed by the Democratic People's Republic of Korea on January 6th, 2016. Confirming a previous statistical observation, the software found more associated stations (51, including 35 primary stations) than GA (36, including 26 primary stations) for this event. Nimar S. Arora, Stuart Russell, Erik Sudderth. Bulletin of the Seismological Society of America (BSSA) April 2013, vol. 103 no. 2A pp709-729.

  5. How can pharmacists develop patient-pharmacist communication skills? A realist review protocol.

    Science.gov (United States)

    Kerr, Aisling; Strawbridge, Judith; Kelleher, Caroline; Mertens, Fien; Pype, Peter; Deveugele, Myriam; Pawlikowska, Teresa

    2017-01-23

    Good patient-pharmacist communication improves health outcomes. There is, however, room for improving pharmacists' communication skills. These develop through complex interactions during undergraduate pharmacy education, practice-based learning and continuing professional development. Research is needed to determine how best to approach teaching patient-pharmacist communication. The aim of the research is to understand how educational interventions develop patient-pharmacist interpersonal communication skills produce their effects. A realist review approach will be used to synthesise the literature to make sense of the complexities of educational interventions. Our review will iteratively progress through the various stages of clarifying scope, locating existing theories, searching for evidence, appraisal of papers, data extraction and synthesis. A scoping review revealed a number of substantive theories, which will be used to build an initial programme theory. This will be explored through available published evidence, which we will find by searching databases such as Medline, EMBASE, PsychInfo, ERIC, Scopus and Web of Science. Judgements will be made on the relevance and rigour of the retrieved literature and will be taken into consideration during analysis and synthesis. Synthesis, testing and refinement of the theories will describe and explain the links between contexts, mechanisms and outcomes of educational interventions for communication development in pharmacy. The realist review will provide an analysis of what works when, for whom, how and why, for educational interventions for interpersonal patient-pharmacist communication development. We will also explore barriers to successful communications training and acknowledge any limitations. Ultimately, we plan to provide pharmacy educators with evidence for how best to incorporate educational interventions for communications skills development into pharmacy curricula and for life-long learning opportunities

  6. Testing local and global stressor impacts on a coastal foundation species using an ecologically realistic framework.

    Science.gov (United States)

    Cheng, Brian S; Bible, Jillian M; Chang, Andrew L; Ferner, Matthew C; Wasson, Kerstin; Zabin, Chela J; Latta, Marilyn; Deck, Anna; Todgham, Anne E; Grosholz, Edwin D

    2015-02-12

    Despite the abundance of literature on organismal responses to multiple environmental stressors, most studies have not matched the timing of experimental manipulations with the temporal pattern of stressors in nature. We test the interactive effects of diel-cycling hypoxia with both warming and decreased salinities using ecologically realistic exposures. Surprisingly, we found no evidence of negative synergistic effects on Olympia oyster growth; rather, we found only additive and opposing effects of hypoxia (detrimental) and warming (beneficial). We suspect that diel-cycling provided a temporal refuge that allowed physiological compensation. We also tested for latent effects of warming and hypoxia to low-salinity tolerance using a seasonal delay between stressor events. However, we did not find a latent effect, rather a threshold survival response to low salinity that was independent of early life-history exposure to warming or hypoxia. The absence of synergism is likely the result of stressor treatments that mirror the natural timing of environmental stressors. We provide environmental context for laboratory experimental data by examining field time series environmental data from four North American west coast estuaries and find heterogeneous environmental signals that characterize each estuary, suggesting that the potential stressor exposure to oysters will drastically differ over moderate spatial scales. This heterogeneity implies that efforts to conserve and restore oysters will require an adaptive approach that incorporates knowledge of local conditions. We conclude that studies of multiple environmental stressors can be greatly improved by integrating ecologically realistic exposure and timing of stressors found in nature with organismal life-history traits. © 2015 John Wiley & Sons Ltd.

  7. Uncovering gender discrimination cues in a realistic setting.

    Science.gov (United States)

    Dupuis-Roy, Nicolas; Fortin, Isabelle; Fiset, Daniel; Gosselin, Frédéric

    2009-02-10

    Which face cues do we use for gender discrimination? Few studies have tried to answer this question and the few that have tried typically used only a small set of grayscale stimuli, often distorted and presented a large number of times. Here, we reassessed the importance of facial cues for gender discrimination in a more realistic setting. We applied Bubbles-a technique that minimizes bias toward specific facial features and does not necessitate the distortion of stimuli-to a set of 300 color photographs of Caucasian faces, each presented only once to 30 participants. Results show that the region of the eyes and the eyebrows-probably in the light-dark channel-is the most important facial cue for accurate gender discrimination; and that the mouth region is driving fast correct responses (but not fast incorrect responses)-the gender discrimination information in the mouth region is concentrated in the red-green color channel. Together, these results suggest that, when color is informative in the mouth region, humans use it and respond rapidly; and, when it's not informative, they have to rely on the more robust but more sluggish luminance information in the eye-eyebrow region.

  8. A Data-Driven Approach to Realistic Shape Morphing

    KAUST Repository

    Gao, Lin

    2013-05-01

    Morphing between 3D objects is a fundamental technique in computer graphics. Traditional methods of shape morphing focus on establishing meaningful correspondences and finding smooth interpolation between shapes. Such methods however only take geometric information as input and thus cannot in general avoid producing unnatural interpolation, in particular for large-scale deformations. This paper proposes a novel data-driven approach for shape morphing. Given a database with various models belonging to the same category, we treat them as data samples in the plausible deformation space. These models are then clustered to form local shape spaces of plausible deformations. We use a simple metric to reasonably represent the closeness between pairs of models. Given source and target models, the morphing problem is casted as a global optimization problem of finding a minimal distance path within the local shape spaces connecting these models. Under the guidance of intermediate models in the path, an extended as-rigid-as-possible interpolation is used to produce the final morphing. By exploiting the knowledge of plausible models, our approach produces realistic morphing for challenging cases as demonstrated by various examples in the paper. © 2013 The Eurographics Association and Blackwell Publishing Ltd.

  9. Towards realistic string vacua from branes at singularities

    Science.gov (United States)

    Conlon, Joseph P.; Maharana, Anshuman; Quevedo, Fernando

    2009-05-01

    We report on progress towards constructing string models incorporating both realistic D-brane matter content and moduli stabilisation with dynamical low-scale supersymmetry breaking. The general framework is that of local D-brane models embedded into the LARGE volume approach to moduli stabilisation. We review quiver theories on del Pezzo n (dPn) singularities including both D3 and D7 branes. We provide supersymmetric examples with three quark/lepton families and the gauge symmetries of the Standard, Left-Right Symmetric, Pati-Salam and Trinification models, without unwanted chiral exotics. We describe how the singularity structure leads to family symmetries governing the Yukawa couplings which may give mass hierarchies among the different generations. We outline how these models can be embedded into compact Calabi-Yau compactifications with LARGE volume moduli stabilisation, and state the minimal conditions for this to be possible. We study the general structure of soft supersymmetry breaking. At the singularity all leading order contributions to the soft terms (both gravity- and anomaly-mediation) vanish. We enumerate subleading contributions and estimate their magnitude. We also describe model-independent physical implications of this scenario. These include the masses of anomalous and non-anomalous U(1)'s and the generic existence of a new hyperweak force under which leptons and/or quarks could be charged. We propose that such a gauge boson could be responsible for the ghost muon anomaly recently found at the Tevatron's CDF detector.

  10. Emulating Realistic Bidirectional Spatial Channels for MIMO OTA Testing

    Directory of Open Access Journals (Sweden)

    Wei Fan

    2015-01-01

    Full Text Available This paper discusses over the air (OTA testing for multiple input multiple output (MIMO capable terminals with emphasis on modeling bidirectional spatial channel models in multiprobe anechoic chamber (MPAC setups. In the literature, work on this topic has been mainly focused on how to emulate downlink channel models, whereas uplink channel is often modeled as free space line-of-sight channel without fading. Modeling realistic bidirectional (i.e., both uplink and downlink propagation environments is essential to evaluate any bidirectional communication systems. There have been works stressing the importance of emulating full bidirectional channel and proposing possible directions to implement uplink channels in the literature. Nevertheless, there is no currently published work reporting an experimental validation of such concepts. In this paper, a general framework to emulate bidirectional channels for time division duplexing (TDD and frequency division duplexing (FDD communication systems is proposed. The proposed technique works for MPAC setups with arbitrary uplink and downlink probe configurations, that is, possibly different probe configurations (e.g., number of probes or their configurations in the uplink and downlink. The simulation results are further supported by measurements in a practical MPAC setup. The proposed algorithm is shown to be a valid method to emulate bidirectional spatial channel models.

  11. From Delivery to Adoption of Physical Activity Guidelines: Realist Synthesis.

    Science.gov (United States)

    Leone, Liliana; Pesce, Caterina

    2017-10-08

    Evidence-based guidelines published by health authorities for the promotion of health-enhancing physical activity (PA), continue to be implemented unsuccessfully and demonstrate a gap between evidence and policies. This review synthesizes evidence on factors influencing delivery, adoption and implementation of PA promotion guidelines within different policy sectors (e.g., health, transport, urban planning, sport, education). Published literature was initially searched using PubMed, EBSCO, Google Scholar and continued through an iterative snowball technique. The literature review spanned the period 2002-2017. The realist synthesis approach was adopted to review the content of 39 included studies. An initial programme theory with a four-step chain from evidence emersion to implementation of guidelines was tested. The synthesis furthers our understanding of the link between PA guidelines delivery and the actions of professionals responsible for implementation within health services, school departments and municipalities. The main mechanisms identified for guidance implementation were scientific legitimation, enforcement, feasibility, familiarity with concepts and PA habits. Threats emerged to the successful implementation of PA guidelines at national/local jurisdictional levels. The way PA guidelines are developed may influence their adoption by policy-makers and professionals. Useful lessons emerged that may inform synergies between policymaking and professional practices, promoting win-win multisectoral strategies.

  12. Conceptual priming for realistic auditory scenes and for auditory words.

    Science.gov (United States)

    Frey, Aline; Aramaki, Mitsuko; Besson, Mireille

    2014-02-01

    Two experiments were conducted using both behavioral and Event-Related brain Potentials methods to examine conceptual priming effects for realistic auditory scenes and for auditory words. Prime and target sounds were presented in four stimulus combinations: Sound-Sound, Word-Sound, Sound-Word and Word-Word. Within each combination, targets were conceptually related to the prime, unrelated or ambiguous. In Experiment 1, participants were asked to judge whether the primes and targets fit together (explicit task) and in Experiment 2 they had to decide whether the target was typical or ambiguous (implicit task). In both experiments and in the four stimulus combinations, reaction times and/or error rates were longer/higher and the N400 component was larger to ambiguous targets than to conceptually related targets, thereby pointing to a common conceptual system for processing auditory scenes and linguistic stimuli in both explicit and implicit tasks. However, fine-grained analyses also revealed some differences between experiments and conditions in scalp topography and duration of the priming effects possibly reflecting differences in the integration of perceptual and cognitive attributes of linguistic and nonlinguistic sounds. These results have clear implications for the building-up of virtual environments that need to convey meaning without words. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. A computational study of routing algorithms for realistic transportation networks

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, R.; Marathe, M.V.; Nagel, K.

    1998-12-01

    The authors carry out an experimental analysis of a number of shortest path (routing) algorithms investigated in the context of the TRANSIMS (Transportation Analysis and Simulation System) project. The main focus of the paper is to study how various heuristic and exact solutions, associated data structures affected the computational performance of the software developed especially for realistic transportation networks. For this purpose the authors have used Dallas Fort-Worth road network with very high degree of resolution. The following general results are obtained: (1) they discuss and experimentally analyze various one-one shortest path algorithms, which include classical exact algorithms studied in the literature as well as heuristic solutions that are designed to take into account the geometric structure of the input instances; (2) they describe a number of extensions to the basic shortest path algorithm. These extensions were primarily motivated by practical problems arising in TRANSIMS and ITS (Intelligent Transportation Systems) related technologies. Extensions discussed include--(i) time dependent networks, (ii) multi-modal networks, (iii) networks with public transportation and associated schedules. Computational results are provided to empirically compare the efficiency of various algorithms. The studies indicate that a modified Dijkstra`s algorithm is computationally fast and an excellent candidate for use in various transportation planning applications as well as ITS related technologies.

  14. Use of clinical guidelines in remote Australia: A realist evaluation.

    Science.gov (United States)

    Reddy, Sandeep; Orpin, Victoria; Herring, Sally; Mackie-Schneider, Stephanie; Struber, Janet

    2017-05-24

    The aim of this evaluation was to assess the acceptability, accessibility, and compliance with the 2014 editions of the Remote Primary Health Care Manuals (RPHCM) in health care centres across remote areas of Northern and Central Australia. To undertake a comprehensive evaluation that considered context, the evaluation used a realist evaluation framework. The evaluation used a variety of methods including interviews and survey to develop and test a programme theory. Many remote health practitioners have adopted standardized, evidence-based practice because of the use of the RPHCM. The mechanisms that led to the use of the manuals include acceptance of the worth of the protocols to their clinical practice, reliance on manual content to guide their practice, the perception of credibility, the applicability of RPHCM content to the context, and a fear of the consequences of not using the RPHCMs. Some remote health practitioners are less inclined to use the RPHCM regularly because of a perception that the content is less suited to their needs and daily practice or it is hard to navigate or understand. The evaluation concluded that there is work to be done to widen the RPHCM user base, and organizations need to increase support for their staff to use the RPHCM protocols better. These measures are expected to enable standardized clinical practice in the remote context. © 2017 John Wiley & Sons, Ltd.

  15. A Realistic Seizure Prediction Study Based on Multiclass SVM.

    Science.gov (United States)

    Direito, Bruno; Teixeira, César A; Sales, Francisco; Castelo-Branco, Miguel; Dourado, António

    2017-05-01

    A patient-specific algorithm, for epileptic seizure prediction, based on multiclass support-vector machines (SVM) and using multi-channel high-dimensional feature sets, is presented. The feature sets, combined with multiclass classification and post-processing schemes aim at the generation of alarms and reduced influence of false positives. This study considers 216 patients from the European Epilepsy Database, and includes 185 patients with scalp EEG recordings and 31 with intracranial data. The strategy was tested over a total of 16,729.80[Formula: see text]h of inter-ictal data, including 1206 seizures. We found an overall sensitivity of 38.47% and a false positive rate per hour of 0.20. The performance of the method achieved statistical significance in 24 patients (11% of the patients). Despite the encouraging results previously reported in specific datasets, the prospective demonstration on long-term EEG recording has been limited. Our study presents a prospective analysis of a large heterogeneous, multicentric dataset. The statistical framework based on conservative assumptions, reflects a realistic approach compared to constrained datasets, and/or in-sample evaluations. The improvement of these results, with the definition of an appropriate set of features able to improve the distinction between the pre-ictal and nonpre-ictal states, hence minimizing the effect of confounding variables, remains a key aspect.

  16. Knowing how to look predicts the ability to draw realistically.

    Science.gov (United States)

    Drake, Jennifer E

    2014-11-01

    Some young children are able to create stunningly realistic drawings resembling those of adult artists. What perceptual abilities underlie this talent? This study examined two candidate skills on which adult artists excel: the ability to segment a complex form mentally (measured by the Block Design Task) and the ability to see hidden forms (measured by the Group Embedded Figures Test). Sixty-seven 6- to 13-year-olds with a wide range of drawing abilities completed these tasks as well as an IQ test and an observational drawing task. While children who scored high on drawing realism outperformed those who scored low in drawing realism on both perceptual tasks, only detection of embedded figures predicted drawing realism. This occurred independently of age, gender, years of training, and verbal and non-verbal IQ. There are certainly many contributors to this complex ability, but one component appears to be the tendency to see things more as they really are and thereby recognize the continuous contour of an object despite interference from other overlapping objects. © 2014 The British Psychological Society.

  17. A realistic 3+1D Viscous Hydro Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Romatschke, Paul [Univ. of Colorado, Boulder, CO (United States)

    2015-05-31

    DoE funds were used as bridge funds for the faculty position for the PI at the University of Colorado. The total funds for the Years 3-5 of the JET Topical Collaboration amounted to about 50 percent of the academic year salary of the PI.The PI contributed to the JET Topical Collaboration by developing, testing and applying algorithms for a realistic simulation of the bulk medium created in relativistic ion collisions.Specifically, two approaches were studied, one based on a new Lattice-Boltzmann (LB) framework, and one on a more traditional viscous hydro-dynamics framework. Both approaches were found to be viable in principle, with the LB approach being more elegant but needing still more time to develop.The traditional approach led to the super-hybrid model of ion collisions dubbed 'superSONIC', and has been successfully used for phenomenology of relativistic heavy-ion and light-on-heavy-ion collisions.In the time-frame of the JET Topical Collaboration, the Colorado group has published 15 articles in peer-reviewed journals, three of which were published in Physical Review Letters. The group graduated one Master student during this time-frame and two more PhD students are expected to graduate in the next few years. The PI has given more than 28 talks and presentations during this period.

  18. OFDM versus Single Carrier: A Realistic Multi-Antenna Comparison

    Directory of Open Access Journals (Sweden)

    Jan Tubbax

    2004-08-01

    Full Text Available There is an ongoing discussion in the broadband wireless world about the respective benefits of orthogonal frequency division multiplexing (OFDM and single carrier with frequency domain equalization (SC-FD. SC-FD allows for more relaxed front-end requirements, of which the power amplifier efficiency is very important for battery-driven terminals. OFDM, on the other hand, can yield improved BER performance at low complexity. Both schemes have extensions to multiple antennas to enhance the spectral efficiency and/or the link reliability. Moreover, both schemes have nonlinear versions using decision feedback equalization (DFE to further improve performance of the linear equalizers. In this paper, we compare these high-performance OFDM and SC-FD schemes using multiple antennas and DFE, while also accounting for the power amplifier efficiency. To make a realistic comparison, we also consider most important digital imperfections, such as channel and noise estimation, transmit and receive filtering, clipping and quantization, as well as link layer impact. Our analysis shows that for frequency-selective channels the relative performance impact of the power amplifier is negligible compared to the frequency diversity impact. The higher frequency diversity exploitation of SC-FD allows it to outperform OFDM in most cases. Therefore, SC-FD is a suitable candidate for broadband wireless communication.

  19. Steering Microbubbles in Physiologically Realistic Flows Using the Bjerknes Force

    Science.gov (United States)

    Clark, Alicia; Aliseda, Alberto

    2017-11-01

    Ultrasound contrast agents (UCAs) are lipid-coated microbubbles that are used to increase contrast in ultrasound imaging due to their ability to scatter sound. Additionally, UCAs can be used in conjunction with ultrasound in medical applications such as targeted drug delivery and thrombolysis. These applications utilize the Bjerknes force, an ultrasound-induced force caused by the phase difference between the incoming ultrasound pressure wave and the microbubble volume oscillations. The dynamics of microbubbles under ultrasound excitation have been studied thoroughly in stagnant fluid baths; however, understanding of the fundamental physics of microbubbles in physiologically realistic flows is lacking. An in vitroexperiment that reproduces the dynamics (Reynolds and Womersley numbers) of a medium-sized blood vessel was used to explore the behavior of microbubbles. Using Lagrangian tracking, the trajectory of each individual bubble was reconstructed using information obtained from high speed imaging. The balance of hydrodynamic forces (lift, drag, added mass, etc.) against the primary Bjerknes force was analyzed. The results show that an increase in ultrasound pulse repetition frequency leads to a linear increase in the Bjerknes force and the increase in the force is quadratic with the amplitude of the excitation.

  20. Factors influencing intercultural doctor-patient communication: a realist review.

    Science.gov (United States)

    Paternotte, Emma; van Dulmen, Sandra; van der Lee, Nadine; Scherpbier, Albert J J A; Scheele, Fedde

    2015-04-01

    Due to migration, doctors see patients from different ethnic backgrounds. This causes challenges for the communication. To develop training programs for doctors in intercultural communication (ICC), it is important to know which barriers and facilitators determine the quality of ICC. This study aimed to provide an overview of the literature and to explore how ICC works. A systematic search was performed to find literature published before October 2012. The search terms used were cultural, communication, healthcare worker. A realist synthesis allowed us to use an explanatory focus to understand the interplay of communication. In total, 145 articles met the inclusion criteria. We found ICC challenges due to language, cultural and social differences, and doctors' assumptions. The mechanisms were described as factors influencing the process of ICC and divided into objectives, core skills and specific skills. The results were synthesized in a framework for the development of training. The quality of ICC is influenced by the context and by the mechanisms. These mechanisms translate into practical points for training, which seem to have similarities with patient-centered communication. Training for improving ICC can be developed as an extension of the existing training for patient-centered communication. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Realistic weight perception and body size assessment in a racially diverse community sample of dieters.

    Science.gov (United States)

    Cachelin, F M; Striegel-Moore, R H; Elder, K A

    1998-01-01

    Recently, a shift in obesity treatment away from emphasizing ideal weight loss goals to establishing realistic weight loss goals has been proposed; yet, what constitutes "realistic" weight loss for different populations is not clear. This study examined notions of realistic shape and weight as well as body size assessment in a large community-based sample of African-American, Asian, Hispanic, and white men and women. Participants were 1893 survey respondents who were all dieters and primarily overweight. Groups were compared on various variables of body image assessment using silhouette ratings. No significant race differences were found in silhouette ratings, nor in perceptions of realistic shape or reasonable weight loss. Realistic shape and weight ratings by both women and men were smaller than current shape and weight but larger than ideal shape and weight ratings. Compared with male dieters, female dieters considered greater weight loss to be realistic. Implications of the findings for the treatment of obesity are discussed.

  2. A realistic pelvic phantom for electrical impedance measurement.

    Science.gov (United States)

    Dunne, Eoghan; McGinley, Brian; O'Halloran, Martin; Porter, Emily

    2017-12-22

    To design and fabricate an anatomically and conductively accurate phantom for electrical impedance studies of non-invasive bladder volume monitoring. Approach: A modular pelvic phantom was designed and fabricated, consisting of a mechanically and conductively stable boundary wall, a background medium, and bladder phantoms. The wall and bladders are made of conductive polyurethane. The background material is an ultrasound gel-based mixture, with conductivity matched to a weighted average of the pelvic cavity organs, bone, muscle and fat. The phantom boundary is developed using a computer tomography model of a male human pelvis. The bladder phantoms were designed to correlate with human bladder dimensions. Electrical impedance measurements of the phantom were recorded, and images produced using six different bladder phantoms and a realistic finite element model. Main results: Five different bladder volumes were successfully imaged using an empty bladder as a reference. The average conductivity index from the reconstructed images showed a strong positive correlation with the bladder phantom volumes. Significance: A conductively and anatomically accurate pelvic phantom was developed for non-invasive bladder volume monitoring using electrical impedance measurements. Several bladders were designed to correlate with actual human bladder volumes, allowing for accurate volume estimation. The conductivity of the phantom is accurate over 50-250 kHz. This phantom can allow: changeable electrode location, contact and size; multi-layer electrodes configurations; increased complexity by addition of other organ or bone phantoms; and electrode movement and deformation. Overall, the pelvic phantom enables greater scope for experimentation and system refinement as a precursor to in-man clinical studies. © 2017 Institute of Physics and Engineering in Medicine.

  3. Realistic camera noise modeling with application to improved HDR synthesis

    Science.gov (United States)

    Goossens, Bart; Luong, Hiêp; Aelterman, Jan; Pižurica, Aleksandra; Philips, Wilfried

    2012-12-01

    Due to the ongoing miniaturization of digital camera sensors and the steady increase of the "number of megapixels", individual sensor elements of the camera become more sensitive to noise, even deteriorating the final image quality. To go around this problem, sophisticated processing algorithms in the devices, can help to maximally exploit the knowledge on the sensor characteristics (e.g., in terms of noise), and offer a better image reconstruction. Although a lot of research focuses on rather simplistic noise models, such as stationary additive white Gaussian noise, only limited attention has gone to more realistic digital camera noise models. In this article, we first present a digital camera noise model that takes several processing steps in the camera into account, such as sensor signal amplification, clipping, post-processing,.. We then apply this noise model to the reconstruction problem of high dynamic range (HDR) images from a small set of low dynamic range (LDR) exposures of a static scene. In literature, HDR reconstruction is mostly performed by computing a weighted average, in which the weights are directly related to the observer pixel intensities of the LDR image. In this work, we derive a Bayesian probabilistic formulation of a weighting function that is near-optimal in the MSE sense (or SNR sense) of the reconstructed HDR image, by assuming exponentially distributed irradiance values. We define the weighting function as the probability that the observed pixel intensity is approximately unbiased. The weighting function can be directly computed based on the noise model parameters, which gives rise to different symmetric and asymmetric shapes when electronic noise or photon noise is dominant. We also explain how to deal with the case that some of the noise model parameters are unknown and explain how the camera response function can be estimated using the presented noise model. Finally, experimental results are provided to support our findings.

  4. Realistic phantoms to characterize dosimetry in pediatric CT

    Energy Technology Data Exchange (ETDEWEB)

    Carver, Diana E.; Kost, Susan D.; Fraser, Nicholas D.; Pickens, David R.; Price, Ronald R.; Stabin, Michael G. [Vanderbilt University Medical Center, Department of Radiology and Radiological Sciences, Nashville, TN (United States); Segars, W.P. [Duke University, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States)

    2017-05-15

    The estimation of organ doses and effective doses for children receiving CT examinations is of high interest. Newer, more realistic anthropomorphic body models can provide information on individual organ doses and improved estimates of effective dose. Previously developed body models representing 50th-percentile individuals at reference ages (newborn, 1, 5, 10 and 15 years) were modified to represent 10th, 25th, 75th and 90th height percentiles for both genders and an expanded range of ages (3, 8 and 13 years). We calculated doses for 80 pediatric reference phantoms from simulated chest-abdomen-pelvis exams on a model of a Philips Brilliance 64 CT scanner. Individual organ and effective doses were normalized to dose-length product (DLP) and fit as a function of body diameter. We calculated organ and effective doses for 80 reference phantoms and plotted them against body diameter. The data were well fit with an exponential function. We found DLP-normalized organ dose to correlate strongly with body diameter (R{sup 2}>0.95 for most organs). Similarly, we found a very strong correlation with body diameter for DLP-normalized effective dose (R{sup 2}>0.99). Our results were compared to other studies and we found average agreement of approximately 10%. We provide organ and effective doses for a total of 80 reference phantoms representing normal-stature children ranging in age and body size. This information will be valuable in replacing the types of vendor-reported doses available. These data will also permit the recording and tracking of individual patient doses. Moreover, this comprehensive dose database will facilitate patient matching and the ability to predict patient-individualized dose prior to examination. (orig.)

  5. Realistic Goals and Processes for Future Space Astronomy Portfolio Planning

    Science.gov (United States)

    Morse, Jon

    2015-08-01

    It is generally recognized that international participation and coordination is highly valuable for maximizing the scientific impact of modern space science facilities, as well as for cost-sharing reasons. Indeed, all large space science missions, and most medium and small missions, are international, even if one country or space agency has a clear leadership role and bears most of the development costs. International coordination is a necessary aspect of future mission planning, but how that coordination is done remains debatable. I propose that the community's scientific vision is generally homogeneous enough to permit international coordination of decadal-scale strategic science goals. However, the timing and budget allocation/funding mechanisms of individual countries and/or space agencies are too disparate for effective long-term strategic portfolio planning via a single international process. Rather, I argue that coordinated space mission portfolio planning is a natural consequence of international collaboration on individual strategic missions. I review the process and outcomes of the U.S. 2010 decadal survey in astronomy & astrophysics from the perspective of a government official who helped craft the survey charter and transmitted guidance to the scientific community on behalf of a sponsoring agency (NASA), while continuing to manage the current portfolio that involved ongoing negotiations with other space agencies. I analyze the difficulties associated with projecting long-term budgets, obtaining realistic mission costs (including the additional cost burdens of international partnerships), and developing new (possibly transformational) technologies. Finally, I remark on the future role that privately funded space science missions can have in accomplishing international science community goals.

  6. Acoustic simulation in realistic 3D virtual scenes

    Science.gov (United States)

    Gozard, Patrick; Le Goff, Alain; Naz, Pierre; Cathala, Thierry; Latger, Jean

    2003-09-01

    The simulation workshop CHORALE developed in collaboration with OKTAL SE company for the French MoD is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain. The main operational reference for CHORALE is the assessment of the infrared guidance system of the Storm Shadow missile French version, called Scalp. The use of CHORALE workshop is now extended to the acoustic domain. The main objective is the simulation of the detection of moving vehicles in realistic 3D virtual scenes. This article briefly describes the acoustic model in CHORALE. The 3D scene is described by a set of polygons. Each polygon is characterized by its acoustic resistivity or its complex impedance. Sound sources are associated with moving vehicles and are characterized by their spectra and directivities. A microphone sensor is defined by its position, its frequency band and its sensitivity. The purpose of the acoustic simulation is to calculate the incoming acoustic pressure on microphone sensors. CHORALE is based on a generic ray tracing kernel. This kernel possesses original capabilities: computation time is nearly independent on the scene complexity, especially the number of polygons, databases are enhanced with precise physical data, special mechanisms of antialiasing have been developed that enable to manage very accurate details. The ray tracer takes into account the wave geometrical divergence and the atmospheric transmission. The sound wave refraction is simulated and rays cast in the 3D scene are curved according to air temperature gradient. Finally, sound diffraction by edges (hill, wall,...) is also taken into account.

  7. Multimodal person authentication on a smartphone under realistic conditions

    Science.gov (United States)

    Morris, Andrew C.; Jassim, Sabah; Sellahewa, Harin; Allano, Lorene; Ehlers, Johan; Wu, Dalei; Koreman, Jacques; Garcia-Salicetti, Sonia; Ly-Van, Bao; Dorizzi, Bernadette

    2006-05-01

    Verification of a person's identity by the combination of more than one biometric trait strongly increases the robustness of person authentication in real applications. This is particularly the case in applications involving signals of degraded quality, as for person authentication on mobile platforms. The context of mobility generates degradations of input signals due to the variety of environments encountered (ambient noise, lighting variations, etc.), while the sensors' lower quality further contributes to decrease in system performance. Our aim in this work is to combine traits from the three biometric modalities of speech, face and handwritten signature in a concrete application, performing non intrusive biometric verification on a personal mobile device (smartphone/PDA). Most available biometric databases have been acquired in more or less controlled environments, which makes it difficult to predict performance in a real application. Our experiments are performed on a database acquired on a PDA as part of the SecurePhone project (IST-2002-506883 project "Secure Contracts Signed by Mobile Phone"). This database contains 60 virtual subjects balanced in gender and age. Virtual subjects are obtained by coupling audio-visual signals from real English speaking subjects with signatures from other subjects captured on the touch screen of the PDA. Video data for the PDA database was recorded in 2 recording sessions separated by at least one week. Each session comprises 4 acquisition conditions: 2 indoor and 2 outdoor recordings (with in each case, a good and a degraded quality recording). Handwritten signatures were captured in one session in realistic conditions. Different scenarios of matching between training and test conditions are tested to measure the resistance of various fusion systems to different types of variability and different amounts of enrolment data.

  8. Realistic respiratory motion margins for external beam partial breast irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, Leigh; Quirk, Sarah [Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta T2N 4N2 (Canada); Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Smith, Wendy L., E-mail: wendy.smith@albertahealthservices.ca [Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta T2N 4N2 (Canada); Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Department of Oncology, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

    2015-09-15

    Purpose: Respiratory margins for partial breast irradiation (PBI) have been largely based on geometric observations, which may overestimate the margin required for dosimetric coverage. In this study, dosimetric population-based respiratory margins and margin formulas for external beam partial breast irradiation are determined. Methods: Volunteer respiratory data and anterior–posterior (AP) dose profiles from clinical treatment plans of 28 3D conformal radiotherapy (3DCRT) PBI patient plans were used to determine population-based respiratory margins. The peak-to-peak amplitudes (A) of realistic respiratory motion data from healthy volunteers were scaled from A = 1 to 10 mm to create respiratory motion probability density functions. Dose profiles were convolved with the respiratory probability density functions to produce blurred dose profiles accounting for respiratory motion. The required margins were found by measuring the distance between the simulated treatment and original dose profiles at the 95% isodose level. Results: The symmetric dosimetric respiratory margins to cover 90%, 95%, and 100% of the simulated treatment population were 1.5, 2, and 4 mm, respectively. With patient set up at end exhale, the required margins were larger in the anterior direction than the posterior. For respiratory amplitudes less than 5 mm, the population-based margins can be expressed as a fraction of the extent of respiratory motion. The derived formulas in the anterior/posterior directions for 90%, 95%, and 100% simulated population coverage were 0.45A/0.25A, 0.50A/0.30A, and 0.70A/0.40A. The differences in formulas for different population coverage criteria demonstrate that respiratory trace shape and baseline drift characteristics affect individual respiratory margins even for the same average peak-to-peak amplitude. Conclusions: A methodology for determining population-based respiratory margins using real respiratory motion patterns and dose profiles in the AP direction was

  9. Track-based event recognition in a realistic crowded environment

    Science.gov (United States)

    van Huis, Jasper R.; Bouma, Henri; Baan, Jan; Burghouts, Gertjan J.; Eendebak, Pieter T.; den Hollander, Richard J. M.; Dijk, Judith; van Rest, Jeroen H.

    2014-10-01

    Automatic detection of abnormal behavior in CCTV cameras is important to improve the security in crowded environments, such as shopping malls, airports and railway stations. This behavior can be characterized at different time scales, e.g., by small-scale subtle and obvious actions or by large-scale walking patterns and interactions between people. For example, pickpocketing can be recognized by the actual snatch (small scale), when he follows the victim, or when he interacts with an accomplice before and after the incident (longer time scale). This paper focusses on event recognition by detecting large-scale track-based patterns. Our event recognition method consists of several steps: pedestrian detection, object tracking, track-based feature computation and rule-based event classification. In the experiment, we focused on single track actions (walk, run, loiter, stop, turn) and track interactions (pass, meet, merge, split). The experiment includes a controlled setup, where 10 actors perform these actions. The method is also applied to all tracks that are generated in a crowded shopping mall in a selected time frame. The results show that most of the actions can be detected reliably (on average 90%) at a low false positive rate (1.1%), and that the interactions obtain lower detection rates (70% at 0.3% FP). This method may become one of the components that assists operators to find threatening behavior and enrich the selection of videos that are to be observed.

  10. On Small Antenna Measurements in a Realistic MIMO Scenario

    DEFF Research Database (Denmark)

    Yanakiev, Boyan; Nielsen, Jesper Ødum; Pedersen, Gert Frølund

    2010-01-01

    This paper deals with the challenges related to evaluating the performance of multiple, small terminal antennas within a natural MIMO environment. The focus is on the antenna measurement accuracy. First a method is presented for measuring small phone mock-ups, with the use of optical fibers...... to base station location, number of base station antennas, antenna prototypes design, user interaction, etc....

  11. Self-diffusion in supercritical water and benzene in high-temperature high-pressure conditions studied by NMR and dynamic solvation-shell model

    Science.gov (United States)

    Yoshida, Ken; Matubayasi, Nobuyuki; Uosaki, Yasuhiro; Nakahara, Masaru

    2010-03-01

    The self-diffusion coefficients of water and organic solvents in the high-temperature high-pressure conditions are studied by using high-temperature NMR and MD simulation methods. The experimental results are analyzed using a scheme based on the solvation shell relaxation time obtained by MD simulation. The dynamic effect of hydrogen bonding is discussed through the comparison between water and a nonpolar organic solvent, benzene, over a wide range of density and temperature. The hydrogen-bonding effects are as follows: (1) the self-diffusion coefficient of water depends on density more weakly than that of benzene, (2) the self-diffusion coefficient of water at the ambient density depends on temperature more strongly than that of benzene at the density, (3) the turnover from the mobile-shell type to the in-shell type with increasing density does not occur in supercritical water up to the ambient density, whereas such turnover is observed in benzene. These contrasts are reflecting the dynamic effect of the anisotropic attractive interactions.

  12. Configuration of Dual Connectivity with Flow Control in a Realistic Urban Scenario

    DEFF Research Database (Denmark)

    Wang, Hua; Gerardino, Guillermo Andrés Pocovi; Rosa, Claudio

    2015-01-01

    the performance of DC in a realistic deployment based on three-dimensional data from a dense urban European capital area, assuming realistic flow control on the backhaul connections between the macro and small cell eNBs. It is found that the configuration of UEs with DC plays a critical role in the performance...

  13. Can Visual Aids in Representational Illustrations Help Pupils to Solve Mathematical Word Problems More Realistically?

    Science.gov (United States)

    Dewolf, Tinne; Van Dooren, Wim; Verschaffel, Lieven

    2017-01-01

    We investigated the effect of two visual aids in representational illustrations on pupils' realistic word problem solving. In part 1 of our study, 288 elementary school pupils received an individual paper-and-pencil task with seven problematic items (P-items) in which realistic considerations need to be made to come to an appropriate reaction.…

  14. Simulating the value of electric-vehicle-grid integration using a behaviourally realistic model

    Science.gov (United States)

    Wolinetz, Michael; Axsen, Jonn; Peters, Jotham; Crawford, Curran

    2018-02-01

    Vehicle-grid integration (VGI) uses the interaction between electric vehicles and the electrical grid to provide benefits that may include reducing the cost of using intermittent renwable electricity or providing a financial incentive for electric vehicle ownerhip. However, studies that estimate the value of VGI benefits have largely ignored how consumer behaviour will affect the magnitude of the impact. Here, we simulate the long-term impact of VGI using behaviourally realistic and empirically derived models of vehicle adoption and charging combined with an electricity system model. We focus on the case where a central entity manages the charging rate and timing for participating electric vehicles. VGI is found not to increase the adoption of electric vehicles, but does have a a small beneficial impact on electricity prices. By 2050, VGI reduces wholesale electricity prices by 0.6-0.7% (0.7 MWh-1, 2010 CAD) relative to an equivalent scenario without VGI. Excluding consumer behaviour from the analysis inflates the value of VGI.

  15. CFD simulations of flow and dust dispersion in a realistic urban area

    Directory of Open Access Journals (Sweden)

    Kun Luo

    2016-01-01

    Full Text Available Fluid flow and dust transportation in a realistic urban residential community under dust storm weather conditions are investigated using computational fluid dynamics (CFD with a grid resolution of several meters. The dust transportation and concentration distribution are obtained through the Lagrangian-formulated discrete particle model by integrating the particle velocity between certain time intervals. The fluid flow is solved by the realizable $ k - \\varepsilon $ model. It is found that the dust transportation and distribution are very closely related to the flow field. The flow field in a real residential community is very complicated. When the building axes are perpendicular to the wind direction, the flows resemble the classic street canyon flow. Places with a low wind speed and high vorticity usually have a high dust concentration. As the wind direction changes, the fluid flow and dust distribution differ from case to case, but the general features are kept. In addition, the building shape and particle-wall interaction conditions have additional effects on the dust distribution, which need further study in the future.

  16. Realistic modeling of the pulse profile of PSR J0737-3039A

    Energy Technology Data Exchange (ETDEWEB)

    Perera, B. B. P.; Kim, C.; McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Ferdman, R. D. [Department of Physics, McGill University, Ernest Rutherford Physics Building, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Kramer, M.; Freire, P. C. C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1 (Canada); Possenti, A. [INAF-Osservatorio Astronomica di Cagliari, Loc. Poggio dei Pini, Strada 54, I-09012 Capoterra (Italy)

    2014-05-20

    The Double Pulsar, PSR J0737-3039A/B, is a unique system in which both neutron stars have been detected as radio pulsars. As shown in Ferdman et al., there is no evidence for pulse profile evolution of the A pulsar, and the geometry of the pulsar was fit well with a double-pole circular radio beam model. Assuming a more realistic polar cap model with a vacuum retarded dipole magnetosphere configuration including special relativistic effects, we create synthesized pulse profiles for A given the best-fit geometry from the simple circular beam model. By fitting synthesized pulse profiles to those observed from pulsar A, we constrain the geometry of the radio beam, namely the half-opening angle and the emission altitude, to be ∼30° and ∼10 neutron star radii, respectively. Combining the observational constraints of PSR J0737-3039A/B, we are able to construct the full three-dimensional orbital geometry of the Double Pulsar. The relative angle between the spin axes of the two pulsars (Δ{sub S}) is estimated to be ∼(138° ± 5°) at the current epoch and will likely remain constant until tidal interactions become important in ∼85 Myr, at merger.

  17. Dynamic Response of an Energy Harvesting Device Under Realistic Flow Conditions

    Science.gov (United States)

    O'Connor, Joseph; Revell, Alistair

    2017-11-01

    The need for reliable, cost-efficient, green energy alternatives has led to increased research in the area of energy harvesting. One approach to energy harvesting is to take advantage of self-sustaining flow-induced vibrations. Through the use of a piezoelectric flag, the mechanical strain from the flapping motion can be converted into electrical energy. While such devices show a lot of promise, the fluid-structure-electrical interactions are highly nonlinear and their response to off-design variations in flow conditions, such as those likely to be encountered upon deployment, is relatively unexplored. The purpose of the present work is to examine how a representative energy harvesting device performs in realistic atmospheric flow conditions involving wind gusts with spatial and temporal variations. A recently developed lattice-Boltzmann-immersed boundary-finite element model is used to perform fully-coupled 3D simulations of the fluid-structure system. For a range of unsteady flow conditions the resulting flow features and structural motion are examined and key behaviour modes are mapped out. The findings of this work will be particularly relevant for self-powered remote sensing networks, which often require deployment in unpredictable and varied environments.

  18. Performance simulation studies of a realistic model of the CBM silicon tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Kotynia, Anna [GSI, Darmstadt (Germany); Collaboration: CBM-Collaboration

    2012-07-01

    One of the most challenging fields of modern high-energy physics is exploration of the phase diagram of strongly interacting matter. In order to study the dynamics of phase diagram at high net baryon densities, the CBM experiment will be performed with high-energy nucleus-nucleus collisions. Efficient charged particle tracking and high momentum resolution are central performance requirements of the CBM Silicon Tracking System (STS). The aim of ongoing layout studies is to design a highly granular and low mass detector system that can track the 1000 charged particles that are typically generated in Au+Au collisions at 25 GeV/u projectile energy. A low mass detector is required to achieve a momentum resolution down to 1%. The simulations of detector response which have been developed include of detector responce include complete chain of physical processes caused by a charged particle traversing the detector - from charge creation in the silicon to the digital output signals. We present the concept of STS geometry, tools used for simulation of realistic detector response together with discussion about results of such simulations.

  19. Realistic Modeling of Fast MHD Wave Trains in Coronal Active Regions

    Science.gov (United States)

    Ofman, Leon; Sun, Xudong

    2017-08-01

    Motivated by recent SDO/AIA observations we have developed realistic modeling of quasi-periodic, fast-mode propagating MHD wave trains (QFPs) using 3D MHD model initiated with potential magnetic field extrapolated from the solar coronal boundary. Localized quasi-periodic pulsations associated with C-class flares that drive the waves (as deduced from observations) are modeled with transverse periodic displacement of magnetic field at the lower coronal boundary. The modeled propagating speed and the form of the wave expansions matches the observed fast MHD waves speed >1000 km/s and topology. We study the parametric dependence of the amplitude, propagation, and damping of the waves for a range of key model parameters, such as the background temperature, density, and the location of the flaring site within the active region. We investigate the interaction of multiple QFP wave trains excited by adjacent flaring sources. We use the model results to synthesize EUV intensities in multiple AIA channels and obtain the model parameters that best reproduce the properties of observed QFPs, such as the recent DEM analysis. We discuss the implications of our modeling results for the seismological application of QFPs for the diagnostic of the active region field, flare pulsations, end estimate the energy flux carried by the waves.

  20. Realistic Modeling of the Pulse Profile of PSR J0737-3039A

    Science.gov (United States)

    Perera, B. B. P.; Kim, C.; McLaughlin, M. A.; Ferdman, R. D.; Kramer, M.; Stairs, I. H.; Freire, P. C. C.; Possenti, A.

    2014-05-01

    The Double Pulsar, PSR J0737-3039A/B, is a unique system in which both neutron stars have been detected as radio pulsars. As shown in Ferdman et al., there is no evidence for pulse profile evolution of the A pulsar, and the geometry of the pulsar was fit well with a double-pole circular radio beam model. Assuming a more realistic polar cap model with a vacuum retarded dipole magnetosphere configuration including special relativistic effects, we create synthesized pulse profiles for A given the best-fit geometry from the simple circular beam model. By fitting synthesized pulse profiles to those observed from pulsar A, we constrain the geometry of the radio beam, namely the half-opening angle and the emission altitude, to be ~30° and ~10 neutron star radii, respectively. Combining the observational constraints of PSR J0737-3039A/B, we are able to construct the full three-dimensional orbital geometry of the Double Pulsar. The relative angle between the spin axes of the two pulsars (ΔS) is estimated to be ~(138° ± 5°) at the current epoch and will likely remain constant until tidal interactions become important in ~85 Myr, at merger.

  1. 3D Realistic Radiative Hydrodynamic Modeling of a Moderate-Mass Star: Effects of Rotation

    Science.gov (United States)

    Kitiashvili, Irina; Kosovichev, Alexander G.; Mansour, Nagi N.; Wray, Alan A.

    2018-01-01

    Recent progress in stellar observations opens new perspectives in understanding stellar evolution and structure. However, complex interactions in the turbulent radiating plasma together with effects of magnetic fields and rotation make inferences of stellar properties uncertain. The standard 1D mixing-length-based evolutionary models are not able to capture many physical processes of stellar interior dynamics, but they provide an initial approximation of the stellar structure that can be used to initialize 3D time-dependent radiative hydrodynamics simulations, based on first physical principles, that take into account the effects of turbulence, radiation, and others. In this presentation we will show simulation results from a 3D realistic modeling of an F-type main-sequence star with mass 1.47 Msun, in which the computational domain includes the upper layers of the radiation zone, the entire convection zone, and the photosphere. The simulation results provide new insight into the formation and properties of the convective overshoot region, the dynamics of the near-surface, highly turbulent layer, the structure and dynamics of granulation, and the excitation of acoustic and gravity oscillations. We will discuss the thermodynamic structure, oscillations, and effects of rotation on the dynamics of the star across these layers.

  2. Improved theory for relativistic transmittance of circularly polarized laser pulses in non-ideal, realistic plasmas

    Science.gov (United States)

    Kang, Teyoun; Kim, Young-Kuk; Hur, Min Sup

    2016-10-01

    Owing to the rapid development of laser technologies, relativistically-induced transmittance (RT) of ultra-intense laser pulses in overdense plasmas is now a practically important matter. RT could give either deleterious or positive effects depending on the kinds of laser-plasma interactions. In radiation-pressure-acceleration (RPA), enhanced transmittance lowers the momentum transfer from the pulse to the ions. Meanwhile, in collisionless-electrostatic-shock, the acceleration efficiency can be increased owing to the effective heating of upstream electrons by transmitted laser fields. Previous theories mostly have handled RT in ideal plasmas, such as an infinitely long uniform plasma or a delta-function-like slab. In the actual applications, however, RT is generally combined with other dynamics, such as plasma density compression, leading to RT under a plasma in other cases. We developed one-dimensional RT theories for circularly polarized laser pulses, which would be used for such realistic plasma profiles. According to our theory, optimal thickness condition should be modified in RPA. Furthermore we developed our theory so that RT in the common two-step density plasma can be modeled. In this poster, we present the derivation and the comparison of the improved theory with PIC simulation results. This work was supported by the Basic Science Research Program (Grant Number NRF-2013R1A1A2006353).

  3. Think Pair Share Using Realistic Mathematics Education Approach in Geometry Learning

    Science.gov (United States)

    Afthina, H.; Mardiyana; Pramudya, I.

    2017-09-01

    This research aims to determine the impact of mathematics learning applying Think Pair Share (TPS) using Realistic Mathematics Education (RME) viewed from mathematical-logical intelligence in geometry learning. Method that used in this research is quasi experimental research The result of this research shows that (1) mathematics achievement applying TPS using RME approach gives a better result than those applying direct learning model; (2) students with high mathematical-logical intelligence can reach a better mathematics achievement than those with average and low one, whereas students with average mathematical-logical intelligence can reach a better achievement than those with low one; (3) there is no interaction between learning model and the level of students’ mathematical-logical intelligence in giving a mathematics achievement. The impact of this research is that TPS model using RME approach can be applied in mathematics learning so that students can learn more actively and understand the material more, and mathematics learning become more meaningful. On the other hand, internal factors of students must become a consideration toward the success of students’ mathematical achievement particularly in geometry material.

  4. Interaction for the trapped fermi gas from a unitary transformation of the exact two-body spectrum

    OpenAIRE

    Rotureau, Jimmy

    2013-01-01

    We study systems of few two-component fermions interacting in a Harmonic Oscillator trap. The fermion-fermion interaction is generated in a finite basis with a unitary transformation of the exact two-body spectrum given by the Busch formula. The few-body Schr\\"odinger equation is solved with the formalism of the No-Core Shell Model. We present results for a system of three fermions interacting at unitarity as well as for finite values of the S-wave scattering length $a_2$ and effective range ...

  5. A Dose of Reality: Radiation Analysis for Realistic Human Spacecraft

    Science.gov (United States)

    Barzilla, J. E.; Lee, K. T.

    2017-01-01

    racks and components, was simplified to remove holes and volume overlaps. Problematic features within the drawing were also removed or repaired to prevent runtime issues. The cleaned drawing was then run through the DAGMC workflow to prepare for analysis. Pilot tests modeling transport of 1GeV proton and 800MeV/A oxygen sources show that reasonable results are converged upon in an acceptable amount of overall computation time from drawing preparation to data analysis. The FLUKA radiation transport code will next be used to model both a GCR and a trapped radiation source. These results will then be compared with measurements that have been made by the radiation instrumentation deployed inside the US Lab module. DISCUSSION Early analyses have indicated that the DAGMC workflow is a promising toolkit for running vehicle geometries of interest to NASA through multiple radiation transport codes. In addition, recent work has shown that a realistic human phantom, provided via a subcontract with the University of Florida, can be placed inside any vehicle geometry for a combinatorial analysis. This added functionality gives the user the ability to score various parameters at the organ level, and the results can then be used as input for cancer risk models.

  6. Combining cell-based hydrodynamics with hybrid particle-field simulations: efficient and realistic simulation of structuring dynamics.

    Science.gov (United States)

    Sevink, G J A; Schmid, F; Kawakatsu, T; Milano, G

    2017-02-22

    We have extended an existing hybrid MD-SCF simulation technique that employs a coarsening step to enhance the computational efficiency of evaluating non-bonded particle interactions. This technique is conceptually equivalent to the single chain in mean-field (SCMF) method in polymer physics, in the sense that non-bonded interactions are derived from the non-ideal chemical potential in self-consistent field (SCF) theory, after a particle-to-field projection. In contrast to SCMF, however, MD-SCF evolves particle coordinates by the usual Newton's equation of motion. Since collisions are seriously affected by the softening of non-bonded interactions that originates from their evaluation at the coarser continuum level, we have devised a way to reinsert the effect of collisions on the structural evolution. Merging MD-SCF with multi-particle collision dynamics (MPCD), we mimic particle collisions at the level of computational cells and at the same time properly account for the momentum transfer that is important for a realistic system evolution. The resulting hybrid MD-SCF/MPCD method was validated for a particular coarse-grained model of phospholipids in aqueous solution, against reference full-particle simulations and the original MD-SCF model. We additionally implemented and tested an alternative and more isotropic finite difference gradient. Our results show that efficiency is improved by merging MD-SCF with MPCD, as properly accounting for hydrodynamic interactions considerably speeds up the phase separation dynamics, with negligible additional computational costs compared to efficient MD-SCF. This new method enables realistic simulations of large-scale systems that are needed to investigate the applications of self-assembled structures of lipids in nanotechnologies.

  7. Nuclear structure of tellurium 133 via beta decay and shell model calculations in the doubly magic tin 132 region. [J,. pi. , transition probabilities, neutron and proton separation, g factors

    Energy Technology Data Exchange (ETDEWEB)

    Lane, S.M.

    1979-08-01

    An experimental investigation of the level structure of /sup 133/Te was performed by spectroscopy of gamma-rays following the beta-decay of 2.7 min /sup 133/Sb. Multiscaled gamma-ray singles spectra and 2.5 x 10/sup 7/ gamma-gamma coincidence events were used in the assignment of 105 of the approximately 400 observed gamma-rays to /sup 133/Sb decay and in the construction of the /sup 133/Te level scheme with 29 excited levels. One hundred twenty-two gamma-rays were identified as originating in the decay of other isotopes of Sb or their daughter products. The remaining gamma-rays were associated with the decay of impurity atoms or have as yet not been identified. A new computer program based on the Lanczos tridiagonalization algorithm using an uncoupled m-scheme basis and vector manipulations was written. It was used to calculate energy levels, parities, spins, model wavefunctions, neutron and proton separation energies, and some electromagnetic transition probabilities for the following nuclei in the /sup 132/Sn region: /sup 128/Sn, /sup 129/Sn, /sup 130/Sn, /sup 131/Sn, /sup 130/Sb, /sup 131/Sb, /sup 132/Sb, /sup 133/Sb, /sup 132/Te, /sup 133/Te, /sup 134/Te, /sup 134/I, /sup 135/I, /sup 135/Xe, and /sup 136/Xe. The results are compared with experiment and the agreement is generally good. For non-magic nuclei: the lg/sub 7/2/, 2d/sub 5/2/, 2d/sub 3/2/, 1h/sub 11/2/, and 3s/sub 1/2/ orbitals are available to valence protons and the 2d/sub 5/2/, 2d/sub 3/2/, 1h/sub 11/2/, and 3s/sub 1/2/ orbitals are available to valence neutron holes. The present CDC7600 computer code can accommodate 59 single particle states and vectors comprised of 30,000 Slater determinants. The effective interaction used was that of Petrovich, McManus, and Madsen, a modification of the Kallio-Kolltveit realistic force. Single particle energies, effective charges and effective g-factors were determined from experimental data for nuclei in the /sup 132/Sn region. 116 references.

  8. A realist review of family-based interventions for children of substance abusing parents.

    Science.gov (United States)

    Usher, Amelia M; McShane, Kelly E; Dwyer, Candice

    2015-12-18

    Millions of children across North America and Europe live in families with alcohol or drug abusing parents. These children are at risk for a number of negative social, emotional and developmental outcomes, including an increased likelihood of developing a substance use disorder later in life. Family-based intervention programs for children with substance abusing parents can yield positive outcomes. This study is a realist review of evaluations of family-based interventions aimed at improving psychosocial outcomes for children of substance abusing parents (COSAPs). The primary objectives were to uncover patterns of contextual factors and mechanisms that generate program outcomes, and advance program theory in this field. Realist review methodology was chosen as the most appropriate method of systematic review because it is a theory-driven approach that seeks to explore mechanisms underlying program effectiveness (or lack thereof). A systematic and comprehensive search of academic and grey literature uncovered 32 documents spanning 7 different intervention programs. Data was extracted from the included documents using abstraction templates designed to code for contexts, mechanisms and outcomes of each program. Two candidate program theories of family addiction were used to guide data analysis: the family disease model and the family prevention model. Data analysis was undertaken by a research team using an iterative process of comparison and checking with original documents to determine patterns within the data. Programs originating in both the family disease model and the family prevention model were uncovered, along with hybrid programs that successfully included components from each candidate program theory. Four demi-regularities were found to account for the effectiveness of programs included in this review: (1) opportunities for positive parent-child interactions, (2) supportive peer-to-peer relationships, (3) the power of knowledge, and (4) engaging hard to

  9. Atomic level insights into realistic molecular models of dendrimer-drug complexes through MD simulations.

    Science.gov (United States)

    Jain, Vaibhav; Maiti, Prabal K; Bharatam, Prasad V

    2016-09-28

    Computational studies performed on dendrimer-drug complexes usually consider 1:1 stoichiometry, which is far from reality, since in experiments more number of drug molecules get encapsulated inside a dendrimer. In the present study, molecular dynamic (MD) simulations were implemented to characterize the more realistic molecular models of dendrimer-drug complexes (1:n stoichiometry) in order to understand the effect of high drug loading on the structural properties and also to unveil the atomistic level details. For this purpose, possible inclusion complexes of model drug Nateglinide (Ntg) (antidiabetic, belongs to Biopharmaceutics Classification System class II) with amine- and acetyl-terminated G4 poly(amidoamine) (G4 PAMAM(NH 2 ) and G4 PAMAM(Ac)) dendrimers at neutral and low pH conditions are explored in this work. MD simulation analysis on dendrimer-drug complexes revealed that the drug encapsulation efficiency of G4 PAMAM(NH 2 ) and G4 PAMAM(Ac) dendrimers at neutral pH was 6 and 5, respectively, while at low pH it was 12 and 13, respectively. Center-of-mass distance analysis showed that most of the drug molecules are located in the interior hydrophobic pockets of G4 PAMAM(NH 2 ) at both the pH; while in the case of G4 PAMAM(Ac), most of them are distributed near to the surface at neutral pH and in the interior hydrophobic pockets at low pH. Structural properties such as radius of gyration, shape, radial density distribution, and solvent accessible surface area of dendrimer-drug complexes were also assessed and compared with that of the drug unloaded dendrimers. Further, binding energy calculations using molecular mechanics Poisson-Boltzmann surface area approach revealed that the location of drug molecules in the dendrimer is not the decisive factor for the higher and lower binding affinity of the complex, but the charged state of dendrimer and drug, intermolecular interactions, pH-induced conformational changes, and surface groups of dendrimer do play an

  10. Gender equity programmes in academic medicine: a realist evaluation approach to Athena SWAN processes.

    Science.gov (United States)

    Caffrey, Louise; Wyatt, David; Fudge, Nina; Mattingley, Helena; Williamson, Catherine; McKevitt, Christopher

    2016-09-08

    Gender inequity has persisted in academic medicine. Yet equity is vital for countries to achieve their full potential in terms of translational research and patient benefit. This study sought to understand how the gender equity programme, Athena SWAN, can be enabled and constrained by interactions between the programme and the context it is implemented into, and whether these interactions might produce unintended consequences. Multimethod qualitative case studies using a realist evaluation approach. 5 departments from a university medical school hosting a Translational Research Organisation. 25 hours of observations of gender equality committee meetings, 16 in-depth interviews with Heads of Departments, Committee Leads and key personnel involved in the initiative. 4 focus groups with 15 postdoctoral researchers, lecturers and senior lecturers. The implementation of Athena SWAN principles was reported to have created social space to address gender inequity and to have highlighted problematic practices to staff. However, a number of factors reduced the programme's potential to impact gender inequity. Gender inequity was reproduced in the programme's enactment as female staff was undertaking a disproportionate amount of Athena SWAN work, with potential negative impacts on individual women's career progression. Early career researchers experienced problems accessing Athena SWAN initiatives. Furthermore, the impact of the programme was perceived to be undermined by wider institutional practices, national policies and societal norms, which are beyond the programme's remit. Gender equity programmes have the potential to address inequity. However, paradoxically, they can also unintentionally reproduce and reinforce gender inequity through their enactment. Potential programme impacts may be undermined by barriers to staff availing of career development and training initiatives, and by wider institutional practices, national policies and societal norms. Published by the

  11. More-Realistic Digital Modeling of a Human Body

    Science.gov (United States)

    Rogge, Renee

    2010-01-01

    A MATLAB computer program has been written to enable improved (relative to an older program) modeling of a human body for purposes of designing space suits and other hardware with which an astronaut must interact. The older program implements a kinematic model based on traditional anthropometric measurements that do provide important volume and surface information. The present program generates a three-dimensional (3D) whole-body model from 3D body-scan data. The program utilizes thin-plate spline theory to reposition the model without need for additional scans.

  12. Sampling Realistic Protein Conformations Using Local Structural Bias

    DEFF Research Database (Denmark)

    Hamelryck, Thomas Wim; Kent, John T.; Krogh, A.

    2006-01-01

    The prediction of protein structure from sequence remains a major unsolved problem in biology. The most successful protein structure prediction methods make use of a divide-and-conquer strategy to attack the problem: a conformational sampling method generates plausible candidate structures, which...... are subsequently accepted or rejected using an energy function. Conceptually, this often corresponds to separating local structural bias from the long-range interactions that stabilize the compact, native state. However, sampling protein conformations that are compatible with the local structural bias encoded...... for protein structure prediction, determination, simulation, and design....

  13. Quantitative description of realistic wealth distributions by kinetic trading models

    Science.gov (United States)

    Lammoglia, Nelson; Muñoz, Víctor; Rogan, José; Toledo, Benjamín; Zarama, Roberto; Valdivia, Juan Alejandro

    2008-10-01

    Data on wealth distributions in trading markets show a power law behavior x-(1+α) at the high end, where, in general, α is greater than 1 (Pareto’s law). Models based on kinetic theory, where a set of interacting agents trade money, yield power law tails if agents are assigned a saving propensity. In this paper we are solving the inverse problem, that is, in finding the saving propensity distribution which yields a given wealth distribution for all wealth ranges. This is done explicitly for two recently published and comprehensive wealth datasets.

  14. Developing realistic stimuli for assessing observers' perceptions of male and female body types.

    Science.gov (United States)

    Salusso-Deonier, C J; Markee, N L; Pedersen, E L

    1991-04-01

    The goal of this research was to create more realistic stimuli for research in assessing observers' perceptions of male and female body types. Stimuli were developed by classifying large samples of photographs and using representative photographs to illustrate body types. Resultant stimuli go beyond current stereotypic stimuli to provide realistic representations of commonly occurring body types among men and women ages 18 ro 40 years. Realistic stimuli can be used in a wide range of research both to understand observer perceptions and to teach the reality of human variation.

  15. Large-Scale Computations Leading to a First-Principles Approach to Nuclear Structure

    Energy Technology Data Exchange (ETDEWEB)

    Ormand, W E; Navratil, P

    2003-08-18

    We report on large-scale applications of the ab initio, no-core shell model with the primary goal of achieving an accurate description of nuclear structure from the fundamental inter-nucleon interactions. In particular, we show that realistic two-nucleon interactions are inadequate to describe the low-lying structure of {sup 10}B, and that realistic three-nucleon interactions are essential.

  16. Feasibility of BCI Control in a Realistic Smart Home Environment

    Directory of Open Access Journals (Sweden)

    Nataliya Kosmyna

    2016-08-01

    Full Text Available Smart homes have been an active area of research, however despite considerable investment, they are not yet a reality for end-users. Moreover, there are still accessibility challenges for the elderly or the disabled, two of the main potential targets for home automation. In this exploratory study we design a control mechanism for smart homes based on Brain Computer Interfaces (BCI and apply it in the Domus smart home platform in order to evaluate the potential interest of users about BCIs at home. We enable users to control lighting, a TV set, a coffee machine and the shutters of the smart home. We evaluate the performance (accuracy, interaction time, usability and feasibility (USE questionnaire on 12 healthy subjects and 2 disabled subjects. We find that healthy subjects achieve 77% task accuracy. However, disabled subjects achieved a better accuracy (81% compared to 77%.

  17. Feasibility of BCI Control in a Realistic Smart Home Environment

    Science.gov (United States)

    Kosmyna, Nataliya; Tarpin-Bernard, Franck; Bonnefond, Nicolas; Rivet, Bertrand

    2016-01-01

    Smart homes have been an active area of research, however despite considerable investment, they are not yet a reality for end-users. Moreover, there are still accessibility challenges for the elderly or the disabled, two of the main potential targets for home automation. In this exploratory study we design a control mechanism for smart homes based on Brain Computer Interfaces (BCI) and apply it in the “Domus”1 smart home platform in order to evaluate the potential interest of users about BCIs at home. We enable users to control lighting, a TV set, a coffee machine and the shutters of the smart home. We evaluate the performance (accuracy, interaction time), usability and feasibility (USE questionnaire) on 12 healthy subjects and 2 disabled subjects. We find that healthy subjects achieve 77% task accuracy. However, disabled subjects achieved a better accuracy (81% compared to 77%). PMID:27616986

  18. Feasibility of BCI Control in a Realistic Smart Home Environment.

    Science.gov (United States)

    Kosmyna, Nataliya; Tarpin-Bernard, Franck; Bonnefond, Nicolas; Rivet, Bertrand

    2016-01-01

    Smart homes have been an active area of research, however despite considerable investment, they are not yet a reality for end-users. Moreover, there are still accessibility challenges for the elderly or the disabled, two of the main potential targets for home automation. In this exploratory study we design a control mechanism for smart homes based on Brain Computer Interfaces (BCI) and apply it in the "Domus" smart home platform in order to evaluate the potential interest of users about BCIs at home. We enable users to control lighting, a TV set, a coffee machine and the shutters of the smart home. We evaluate the performance (accuracy, interaction time), usability and feasibility (USE questionnaire) on 12 healthy subjects and 2 disabled subjects. We find that healthy subjects achieve 77% task accuracy. However, disabled subjects achieved a better accuracy (81% compared to 77%).

  19. The Management of Long-Term Sickness Absence in Large Public Sector Healthcare Organisations: A Realist Evaluation Using Mixed Methods.

    Science.gov (United States)

    Higgins, Angela; O'Halloran, Peter; Porter, Sam

    2015-09-01

    The success of measures to reduce long-term sickness absence (LTSA) in public sector organisations is contingent on organisational context. This realist evaluation investigates how interventions interact with context to influence successful management of LTSA. Multi-method case study in three Health and Social Care Trusts in Northern Ireland comprising realist literature review, semi-structured interviews (61 participants), Process-Mapping and feedback meetings (59 participants), observation of training, analysis of documents. Important activities included early intervention; workplace-based occupational rehabilitation; robust sickness absence policies with clear trigger points for action. Used appropriately, in a context of good interpersonal and interdepartmental communication and shared goals, these are able to increase the motivation of staff to return to work. Line managers are encouraged to take a proactive approach when senior managers provide support and accountability. Hindering factors: delayed intervention; inconsistent implementation of policy and procedure; lack of resources; organisational complexity; stakeholders misunderstanding each other's goals and motives. Different mechanisms have the potential to encourage common motivations for earlier return from LTSA, such as employees feeling that they have the support of their line manager to return to work and having the confidence to do so. Line managers' proactively engage when they have confidence in the support of seniors and in their own ability to address LTSA. Fostering these motivations calls for a thoughtful, diagnostic process, taking into account the contextual factors (and whether they can be modified) and considering how a given intervention can be used to trigger the appropriate mechanisms.

  20. Realistic Avatar Eye and Head Animation Using a Neurobiological Model of Visual Attention

    National Research Council Canada - National Science Library

    Itti, L; Dhavale, N; Pighin, F

    2003-01-01

    We describe a neurobiological model of visual attention and eye/head movements in primates, and its application to the automatic animation of a realistic virtual human head watching an unconstrained...

  1. Book Review: A Liberal Actor in a Realist World the European Union ...

    African Journals Online (AJOL)

    Abstract. Book Title: A Liberal Actor in a Realist World the European Union Regulatory State and the Global Political Economy of Energy. Book Author: Andreas Goldthau & Nick Sitter. Oxford University Press Oxford 2015. ISBN 9780198719595 ...

  2. Development of Realistic Head Models for Electromagnetic Source Imaging of the Human Brain

    National Research Council Canada - National Science Library

    Akalin, Z

    2001-01-01

    ... images is performed Then triangular, quadratic meshes are formed for the interfaces of the tissues, Thus, realistic meshes, representing scalp, skull, CSF, brain and eye tissues, are formed, At least...

  3. Approach to sensor node calibration for efficient localisation in wireless sensor networks in realistic scenarios

    CSIR Research Space (South Africa)

    Mwila, MK

    2014-06-01

    Full Text Available propagation basic mechanisms is a fundamental step toward the design of ranging and localisation algorithms able to work properly in realistic scenarios. Furthermore, positioning systems are migrating towards hybridisation where data coming from heterogeneous...

  4. Computational investigation of nonlinear microwave tomography on anatomically realistic breast phantoms

    DEFF Research Database (Denmark)

    Jensen, P. D.; Rubæk, Tonny; Mohr, J. J.

    2013-01-01

    The performance of a nonlinear microwave tomography algorithm is tested using simulated data from anatomically realistic breast phantoms. These tests include several different anatomically correct breast models from the University of Wisconsin-Madison repository with and without tumors inserted....

  5. Satisfaction and sustainability: a realist review of decentralized models of perinatal surgery for rural women

    National Research Council Canada - National Science Library

    Kornelsen, Jude; McCartney, Kevin; Williams, Kim

    2016-01-01

    This article was developed as part of a larger realist review investigating the viability and efficacy of decentralized models of perinatal surgical services for rural women in the context of recent...

  6. The effects of presenting multidigit mathematics problems in a realistic context on sixth graders' problem solving

    NARCIS (Netherlands)

    Hickendorff, M.

    2013-01-01

    Mathematics education and assessments increasingly involve arithmetic problems presented in context: a realistic situation that requires mathematical modeling. This study assessed the effects of such typical school mathematics contexts on two aspects of problem solving: performance and strategy use.

  7. A Realistic Approach To Evaluating Digital Imaging Systems

    Science.gov (United States)

    Greinacher, C. F.; Bach, E.,; Muller, K.,; Patzelt, K.

    1984-06-01

    Current systems for the production of medical images and current development trends give a basis of experience for the design of a digital PACS including images and demographic data. Such a PACS must contain software and hardware concepts which permit the medical requirements, as presently understood, to be realized. As part of its research Siemens is designing and evaluating a hybrid network configuration which allows extensive flexibility and growth potential despite current limitations in available network bandwidth and storage capacity. As demand for digital data expands, additional installations can be added to the system. The modular concept permits incorporation of technological advances with minimal difficulty. The system allows different digital imaging modalities to communicate with a central data storage and processing system. Data display facilities both with and without manipulation capability are realized using high speed multi image storage devices. The human interface is designed to be ergono-metric, interactive, and user-friendly. Standardized, commercially available hardware has been included wherever possible to provide economical worldwide acceptance. Estimates of digital data per unit time under different conditions are presented and compared to the specifications of software and hardware elements both currently available and envisaged in the near future. Potential limitations of the design, as well as possible solutions incorporating expected technological developments, are discussed.

  8. Realistic computer network simulation for network intrusion detection dataset generation

    Science.gov (United States)

    Payer, Garrett

    2015-05-01

    The KDD-99 Cup dataset is dead. While it can continue to be used as a toy example, the age of this dataset makes it all but useless for intrusion detection research and data mining. Many of the attacks used within the dataset are obsolete and do not reflect the features important for intrusion detection in today's networks. Creating a new dataset encompassing a large cross section of the attacks found on the Internet today could be useful, but would eventually fall to the same problem as the KDD-99 Cup; its usefulness would diminish after a period of time. To continue research into intrusion detection, the generation of new datasets needs to be as dynamic and as quick as the attacker. Simply examining existing network traffic and using domain experts such as intrusion analysts to label traffic is inefficient, expensive, and not scalable. The only viable methodology is simulation using technologies including virtualization, attack-toolsets such as Metasploit and Armitage, and sophisticated emulation of threat and user behavior. Simulating actual user behavior and network intrusion events dynamically not only allows researchers to vary scenarios quickly, but enables online testing of intrusion detection mechanisms by interacting with data as it is generated. As new threat behaviors are identified, they can be added to the simulation to make quicker determinations as to the effectiveness of existing and ongoing network intrusion technology, methodology and models.

  9. Towards a realistic event generator for in-medium signals

    Energy Technology Data Exchange (ETDEWEB)

    Seck, Florian [TU Darmstadt (Germany); Collaboration: HADES-Collaboration

    2015-07-01

    The most important task of theoretical heavy-ion physics is to link experimental observables to the bulk properties and the microscopic structure of the different phases of strongly interacting matter. Until now the hadronic cocktails produced with the event generator Pluto for the HADES and CBM experiments only included a contribution from freeze-out ρ mesons modeled by a Breit-Wigner distribution around its pole mass. However as dileptons are radiated from the fireball during the whole time evolution, medium effects like the broadening of the ρ should also be included in the simulations. Calculations of the in-medium ρ spectral function by R. Rapp and J. Wambach demonstrate, that a large part of the in-medium ρ mesons feed into the mass region below the ρ/ω pole mass down to zero masses. The modular structure of Pluto makes it feasible to customize the event generator and incorporate models of in-medium physics, like the Rapp-Wambach spectral function, as plug-ins. For masses above 1 GeV/c{sup 2} we include emission due to multi-pion annihilation and due to QGP radiation. In this contribution first steps towards the implementation of such a plug-in into the event generator Pluto are presented.

  10. The Sobering Reality of Perovskite/Si Tandem Solar Cells under Realistic Operating Conditions

    OpenAIRE

    Futscher, Moritz H.; Ehrler, Bruno

    2017-01-01

    Perovskite/Si tandem solar cells have the potential to considerably out-perform conventional solar cells. Under standard test conditions, perovskite/Si tandem solar cells already outperform the Si single junction. Under realistic conditions, however, as we show, tandem solar cells made from current record cells are hardly more efficient than the Si cell alone. We model the performance of realistic perovskite/Si tandem solar cells under real-world climate conditions, by incorporating parasitic...

  11. Realistic Hot Water Draw Specification for Rating Solar Water Heaters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Burch, J.

    2012-06-01

    In the United States, annual performance ratings for solar water heaters are simulated, using TMY weather and specified water draw. A more-realistic ratings draw is proposed that eliminates most bias by improving mains inlet temperature and by specifying realistic hot water use. This paper outlines the current and the proposed draws and estimates typical ratings changes from draw specification changes for typical systems in four cities.

  12. The realist claim of fallibilism: A critique of the realism of Karl Popper

    Directory of Open Access Journals (Sweden)

    Rafael Fayos Febrer

    2015-01-01

    Full Text Available This article revises Karl Popper’s realism and examines how far he was a realist or simply he tried to be. Distinguishing between two areas of realism, a general one against the idealism, and the other more specific as part of the philosophy of the science, we analyze Popper’s realism coming to the conclusion that we are facing a fake, and at the same time, precarious realism. Popper was, in any case, a Kantian realist.

  13. Theoretical and applied research on bistable dual-piezoelectric-cantilever vibration energy harvesting toward realistic ambience

    Science.gov (United States)

    Gao, Y.; Leng, Y.; Javey, A.; Tan, D.; Liu, J.; Fan, S.; Lai, Z.

    2016-11-01

    Pink noise, which is similar to realistic ambient noise, is normally used to simulate ambience where a piezoelectric energy harvesting system (PEHS) is set up. However, pink noise with standard spectral representation can only be used to simulate excitations assumed to possess constant intensity, whereas realistic ambient noise normally appears with a random spectrum and varying intensity in terms of different locations and time. The output performance of conventional bistable magnetic repulsive energy harvesters is significantly affected by the ambience intensity. Considering this fact, a model bistable dual-piezoelectric-cantilever energy harvester (DPEH) is developed in this study to achieve optimal broadband energy harvesting under a varying-intensity realistic circumstance. We utilized various realistic ambient conditions as excitations to obtain the DPEH energy harvesting performance for theoretical and applied study. The elastically supported PEHS has been proven to be more adaptive to realistic ambience with significant or medium intensity variation, but is less qualified for realistic ambience with constant intensity compared with the rigidly supported PEHS (RPEHS). Fortunately, the dual-piezoelectric-cantilever energy harvesting system is superior to the RPEHS under all circumstances because the dual-piezoelectric cantilevers are efficiently utilized for electromechanical energy conversion to realize optimal energy harvesting.

  14. Human agency beliefs influence behaviour during virtual social interactions

    National Research Council Canada - National Science Library

    Brock, Jon; Caruana, Nathan; Spirou, Dean

    2017-01-01

    In recent years, with the emergence of relatively inexpensive and accessible virtual reality technologies, it is now possible to deliver compelling and realistic simulations of human-to-human interaction...

  15. DMTO: a realistic ontology for standard diabetes mellitus treatment.

    Science.gov (United States)

    El-Sappagh, Shaker; Kwak, Daehan; Ali, Farman; Kwak, Kyung-Sup

    2018-02-06

    Treatment of type 2 diabetes mellitus (T2DM) is a complex problem. A clinical decision support system (CDSS) based on massive and distributed electronic health record data can facilitate the automation of this process and enhance its accuracy. The most important component of any CDSS is its knowledge base. This knowledge base can be formulated using ontologies. The formal description logic of ontology supports the inference of hidden knowledge. Building a complete, coherent, consistent, interoperable, and sharable ontology is a challenge. This paper introduces the first version of the newly constructed Diabetes Mellitus Treatment Ontology (DMTO) as a basis for shared-semantics, domain-specific, standard, machine-readable, and interoperable knowledge relevant to T2DM treatment. It is a comprehensive ontology and provides the highest coverage and the most complete picture of coded knowledge about T2DM patients' current conditions, previous profiles, and T2DM-related aspects, including complications, symptoms, lab tests, interactions, treatment plan (TP) frameworks, and glucose-related diseases and medications. It adheres to the design principles recommended by the Open Biomedical Ontologies Foundry and is based on ontological realism that follows the principles of the Basic Formal Ontology and the Ontology for General Medical Science. DMTO is implemented under Protégé 5.0 in Web Ontology Language (OWL) 2 format and is publicly available through the National Center for Biomedical Ontology's BioPortal at http://bioportal.bioontology.org/ontologies/DMTO . The current version of DMTO includes more than 10,700 classes, 277 relations, 39,425 annotations, 214 semantic rules, and 62,974 axioms. We provide proof of concept for this approach to modeling TPs. The ontology is able to collect and analyze most features of T2DM as well as customize chronic TPs with the most appropriate drugs, foods, and physical exercises. DMTO is ready to be used as a knowledge base for

  16. A computational framework for cortical microtubule dynamics in realistically shaped plant cells

    KAUST Repository

    Chakrabortty, Bandan

    2018-02-02

    Plant morphogenesis is strongly dependent on the directional growth and the subsequent oriented division of individual cells. It has been shown that the plant cortical microtubule array plays a key role in controlling both these processes. This ordered structure emerges as the collective result of stochastic interactions between large numbers of dynamic microtubules. To elucidate this complex self-organization process a number of analytical and computational approaches to study the dynamics of cortical microtubules have been proposed. To date, however, these models have been restricted to two dimensional planes or geometrically simple surfaces in three dimensions, which strongly limits their applicability as plant cells display a wide variety of shapes. This limitation is even more acute, as both local as well as global geometrical features of cells are expected to influence the overall organization of the array. Here we describe a framework for efficiently simulating microtubule dynamics on triangulated approximations of arbitrary three dimensional surfaces. This allows the study of microtubule array organization on realistic cell surfaces obtained by segmentation of microscopic images. We validate the framework against expected or known results for the spherical and cubical geometry. We then use it to systematically study the individual contributions of global geometry, cell-edge induced catastrophes and cell-face induced stability to array organization in a cuboidal geometry. Finally, we apply our framework to analyze the highly non-trivial geometry of leaf pavement cells of Arabidopsis thaliana, Nicotiana benthamiana and Hedera helix. We show that our simulations can predict multiple features of the microtubule array structure in these cells, revealing, among others, strong constraints on the orientation of division planes.

  17. Electromagnetic field effect simulation over a realistic pixel ed phantom human's brain

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, R.; Calderon, J. A.; Rivera, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Calz. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin, J., E-mail: rafaelturing@prodigy.net.mx [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2012-10-15

    The exposition to different types of electromagnetic radiations can produce damages and injures on the people's tissues. The scientist, spend time and resources studying the effects of electromagnetic fields over the organs. Particularly in medical areas, the specialist in imaging methodologies and radiological treatment, are very worried about no injure there patient. Determination of matter radiation interaction, can be experimental or theoretical is not an easy task anyway. At first case, is not possible make measures inside the patient, then the experimental procedure consist in make measures in human's dummy, however, is not possible see deformations of electromagnetic fields due the organs presence. In the second case, is necessary solve, the Maxwell's equations with the electromagnetic field, crossing a lot of organs and tissues with different electric and magnetic properties each one. One alternative for theoretical solution, is make a computational simulation, however, this option, require an enormous quantity of memory and large computational times. Then, the most simulations are making in 2 dimensional or in 3 dimensional although using human models approximations, build ed with basic geometrical figures, like spheres, cylinders, ellipsoids, etc. Obviously this models just lets obtain a coarse solution of the actually situation. In this work, we propose a novel methodology to build a realistic pixel ed phantom of human's organs, and solve the Maxwell's equations over this models, evidently, the solutions are more approximated to the real behaviour. Additionally, there models results optimized when they are discretized and the finite element method is used to calculate the electromagnetic field and the induced currents. (Author)

  18. Accurately decoding visual information from fMRI data obtained in a realistic virtual environment

    Directory of Open Access Journals (Sweden)

    Andrew eFloren

    2015-06-01

    Full Text Available Three-dimensional interactive virtual environments are a powerful tool for brain-imaging based cognitive neuroscience that are presently under-utilized. This paper presents machine-learning based methods for identifying brain states induced by realistic virtual environments with improved accuracy as well as the capability for mapping their spatial topography on the neocortex. Virtual environments provide the ability to study the brain under conditions closer to the environment in which humans evolved, and thus to probe deeper into the complexities of human cognition. As a test case, we designed a stimulus to reflect a military combat situation in the Middle East, motivated by the potential of using real-time functional magnetic resonance imaging (fMRI in the treatment of post-traumatic stress disorder. Each subject experienced moving through the virtual town where they encountered 1—6 animated combatants at different locations, while fMRI data was collected. To analyze the data from what is, compared to most studies, more complex and less controlled stimuli, we employed statistical machine learning in the form of Multi-Voxel Pattern Analysis (MVPA with special attention given to artificial Neural Networks (NN. Extensions to NN that exploit the block structure of the stimulus were developed to improve the accuracy of the classification, achieving performances from 58%—93% (chance was 16.7% with 6 subjects. This demonstrates that MVPA can decode a complex cognitive state, viewing a number of characters, in a dynamic virtual environment. To better understand the source of this information in the brain, a novel form of sensitivity analysis was developed to use NN to quantify the degree to which each voxel contributed to classification. Compared with maps produced by general linear models and the searchlight approach, these sensitivity maps revealed a more diverse pattern of information relevant to the classification of cognitive state.

  19. Towards realistic representation of hydrological processes in integrated WRF-urban modeling system

    Science.gov (United States)

    Yang, Jiachuan; Wang, Zhi-hua; Chen, Fei; Miao, Shiguang; Tewari, Mukul; Georgescu, Matei

    2014-05-01

    To meet the demand of the ever-increasing urbanized global population, substantial conversion of natural landscapes to urban terrains is expected in the next few decades. The landscape modification will emerge as the source of many adverse effects that challenge the environmental sustainability of cities under changing climatic patterns. To address these adverse effects and to develop corresponding adaptation/mitigation strategies, physically-based single layer urban canopy model (SLUCM) has been developed and implemented into the Weather Research and Forecasting (WRF) platform. However, due to the lack of realistic representation of urban hydrological processes, simulation of urban climatology by current coupled WRF/SLUCM is inevitably inadequate. Aiming at improving the accuracy of simulations, in this study we implement physically-based parameterization of urban hydrological processes into the model, including (1) anthropogenic latent heat, (2) urban irrigation, (3) evaporation over water-holding engineered pavements, (4) urban oasis effect, and (5) green roof. In addition, we use an advanced Monte Carlo approach to quantify the sensitivity of urban hydrological modeling to parameter uncertainties. Evaluated against field observations at four major metropolitan areas, results show that the enhanced model is significantly improved in accurately predicting turbulent fluxes arising from built surfaces, especially the latent heat flux. Case studies show that green roof is capable of reducing urban surface temperature and sensible heat flux effectively, and modifying local and regional hydroclimate. Meanwhile, it is efficient in decreasing energy loading of buildings, not only cooling demand in summers but also heating demand in winters, through the combined evaporative cooling and insulation effect. Effectiveness of green roof is found to be limited by availability of water resources and highly sensitive to surface roughness heights. The enhanced WRF/SLUCM model

  20. Pre-registration interprofessional clinical education in the workplace: a realist review.

    Science.gov (United States)

    Kent, Fiona; Hayes, Jacinta; Glass, Sharon; Rees, Charlotte E

    2017-09-01

    The inclusion of interprofessional education opportunities in clinical placements for pre-registration learners has recently been proposed as a strategy to enhance graduates' skills in collaborative practice. A realist review was undertaken to ascertain the contexts, mechanisms and outcomes of formal interprofessional clinical workplace learning. Initial scoping was carried out, after which Ovid MEDLINE, CINAHL and EMBASE were searched from 2005 to April 2016 to identify formal interprofessional workplace educational interventions involving pre-registration learners. Papers reporting studies conducted in dedicated training wards were excluded, leaving a total of 30 papers to be included in the review. Several educational formats that combined students from medicine, nursing, pharmacy and allied health professions were identified. These included: the use of engagement by student teams with a real patient through interview as the basis for discussion and reflection; the use of case studies through which student teams work to promote discussion; structured workshops; ward rounds, and shadowing. Meaningful interprofessional student discussion and reflection comprised the mechanism by which the outcome of learners acquiring knowledge of the roles of other professions and teamwork skills was achieved. The mechanism of dialogue during an interaction with a real patient allowed the patient to provide his or her perspective and contributed to an awareness of the patient's perspective in health care practice. Medication- or safety-focused interprofessional tasks contributed to improved safety awareness. In the absence of trained facilitators or in the context of negative role-modelling, programmes were less successful. In the design of workplace education initiatives, curriculum decisions should take into consideration the contexts of the initiatives and the mechanisms for achieving the education-related outcomes of interest. © 2017 John Wiley & Sons Ltd and The Association

  1. Evolutionary approaches for the reverse-engineering of gene regulatory networks: A study on a biologically realistic dataset

    Directory of Open Access Journals (Sweden)

    Gidrol Xavier

    2008-02-01

    Full Text Available Abstract Background Inferring gene regulatory networks from data requires the development of algorithms devoted to structure extraction. When only static data are available, gene interactions may be modelled by a Bayesian Network (BN that represents the presence of direct interactions from regulators to regulees by conditional probability distributions. We used enhanced evolutionary algorithms to stochastically evolve a set of candidate BN structures and found the model that best fits data without prior knowledge. Results We proposed various evolutionary strategies suitable for the task and tested our choices using simulated data drawn from a given bio-realistic network of 35 nodes, the so-called insulin network, which has been used in the literature for benchmarking. We assessed the inferred models against this reference to obtain statistical performance results. We then compared performances of evolutionary algorithms using two kinds of recombination operators that operate at different scales in the graphs. We introduced a niching strategy that reinforces diversity through the population and avoided trapping of the algorithm in one local minimum in the early steps of learning. We show the limited effect of the mutation operator when niching is applied. Finally, we compared our best evolutionary approach with various well known learning algorithms (MCMC, K2, greedy search, TPDA, MMHC devoted to BN structure learning. Conclusion We studied the behaviour of an evolutionary approach enhanced by niching for the learning of gene regulatory networks with BN. We show that this approach outperforms classical structure learning methods in elucidating the original model. These results were obtained for the learning of a bio-realistic network and, more importantly, on various small datasets. This is a suitable approach for learning transcriptional regulatory networks from real datasets without prior knowledge.

  2. Species traits outweigh nested structure in driving the effects of realistic biodiversity loss on productivity.

    Science.gov (United States)

    Wolfi, Amelia A; Zavaleta, Erika S

    2015-01-01

    While most studies of the relationship between biodiversity and ecosystem functioning have examined randomized diversity losses, several recent experiments have employed nested, realistic designs and found that realistic species losses had larger consequences than random losses for ecosystem functioning. Progressive, realistic, biodiversity losses are generally strongly nested, but this nestedness is a potentially confounding effect. Here, we address whether nonrandom trait loss or degree of nestedness drives the relationship between diversity and productivity in a realistic biodiversity-loss experiment. We isolated the effect of nestedness through post hoc analyses of data from an experimental biodiversity manipulation in a California serpentine grassland. We found that the order in which plant traits are lost as diversity declines influences the diversity-productivity relationship more than the degree of nestedness does. Understanding the relationship between the expected order of species loss and functional traits is becoming increasingly important in the face of ongoing biodiversity loss worldwide. Our findings illustrate the importance of species composition and the order of species loss, rather than nestedness per se, for understanding the mechanisms underlying the effects of realistic species losses on ecosystem functioning.

  3. A Low-cost System for Generating Near-realistic Virtual Actors

    Science.gov (United States)

    Afifi, Mahmoud; Hussain, Khaled F.; Ibrahim, Hosny M.; Omar, Nagwa M.

    2015-06-01

    Generating virtual actors is one of the most challenging fields in computer graphics. The reconstruction of a realistic virtual actor has been paid attention by the academic research and the film industry to generate human-like virtual actors. Many movies were acted by human-like virtual actors, where the audience cannot distinguish between real and virtual actors. The synthesis of realistic virtual actors is considered a complex process. Many techniques are used to generate a realistic virtual actor; however they usually require expensive hardware equipment. In this paper, a low-cost system that generates near-realistic virtual actors is presented. The facial features of the real actor are blended with a virtual head that is attached to the actor's body. Comparing with other techniques that generate virtual actors, the proposed system is considered a low-cost system that requires only one camera that records the scene without using any expensive hardware equipment. The results of our system show that the system generates good near-realistic virtual actors that can be used on many applications.

  4. A realist evaluation of the management of a well-performing regional hospital in Ghana.

    Science.gov (United States)

    Marchal, Bruno; Dedzo, McDamien; Kegels, Guy

    2010-01-25

    Realist evaluation offers an interesting approach to evaluation of interventions in complex settings, but has been little applied in health care. We report on a realist case study of a well performing hospital in Ghana and show how such a realist evaluation design can help to overcome the limited external validity of a traditional case study. We developed a realist evaluation framework for hypothesis formulation, data collection, data analysis and synthesis of the findings. Focusing on the role of human resource management in hospital performance, we formulated our hypothesis around the high commitment management concept. Mixed methods were used in data collection, including individual and group interviews, observations and document reviews. We found that the human resource management approach (the actual intervention) included induction of new staff, training and personal development, good communication and information sharing, and decentralised decision-making. We identified 3 additional practices: ensuring optimal physical working conditions, access to top managers and managers' involvement on the work floor. Teamwork, recognition and trust emerged as key elements of the organisational climate. Interviewees reported high levels of organisational commitment. The analysis unearthed perceived organisational support and reciprocity as underlying mechanisms that link the management practices with commitment. Methodologically, we found that realist evaluation can be fruitfully used to develop detailed case studies that analyse how management interventions work and in which conditions. Analysing the links between intervention, mechanism and outcome increases the explaining power, while identification of essential context elements improves the usefulness of the findings for decision-makers in other settings (external validity). We also identified a number of practical difficulties and priorities for further methodological development. This case suggests that a well

  5. A realist evaluation of the management of a well- performing regional hospital in Ghana

    Directory of Open Access Journals (Sweden)

    Kegels Guy

    2010-01-01

    Full Text Available Abstract Background Realist evaluation offers an interesting approach to evaluation of interventions in complex settings, but has been little applied in health care. We report on a realist case study of a well performing hospital in Ghana and show how such a realist evaluation design can help to overcome the limited external validity of a traditional case study. Methods We developed a realist evaluation framework for hypothesis formulation, data collection, data analysis and synthesis of the findings. Focusing on the role of human resource management in hospital performance, we formulated our hypothesis around the high commitment management concept. Mixed methods were used in data collection, including individual and group interviews, observations and document reviews. Results We found that the human resource management approach (the actual intervention included induction of new staff, training and personal development, good communication and information sharing, and decentralised decision-making. We identified 3 additional practices: ensuring optimal physical working conditions, access to top managers and managers' involvement on the work floor. Teamwork, recognition and trust emerged as key elements of the organisational climate. Interviewees reported high levels of organisational commitment. The analysis unearthed perceived organisational support and reciprocity as underlying mechanisms that link the management practices with commitment. Methodologically, we found that realist evaluation can be fruitfully used to develop detailed case studies that analyse how management interventions work and in which conditions. Analysing the links between intervention, mechanism and outcome increases the explaining power, while identification of essential context elements improves the usefulness of the findings for decision-makers in other settings (external validity. We also identified a number of practical difficulties and priorities for further

  6. A realist evaluation of the role of communities of practice in changing healthcare practice

    Directory of Open Access Journals (Sweden)

    Westbrook Johanna I

    2011-05-01

    Full Text Available Abstract Background Healthcare organisations seeking to manage knowledge and improve organisational performance are increasingly investing in communities of practice (CoPs. Such investments are being made in the absence of empirical evidence demonstrating the impact of CoPs in improving the delivery of healthcare. A realist evaluation is proposed to address this knowledge gap. Underpinned by the principle that outcomes are determined by the context in which an intervention is implemented, a realist evaluation is well suited to understand the role of CoPs in improving healthcare practice. By applying a realist approach, this study will explore the following questions: What outcomes do CoPs achieve in healthcare? Do these outcomes translate into improved practice in healthcare? What are the contexts and mechanisms by which CoPs improve healthcare? Methods The realist evaluation will be conducted by developing, testing, and refining theories on how, why, and when CoPs improve healthcare practice. When collecting data, context will be defined as the setting in which the CoP operates; mechanisms will be the factors and resources that the community offers to influence a change in behaviour or action; and outcomes will be defined as a change in behaviour or work practice that occurs as a result of accessing resources provided by the CoP. Discussion Realist evaluation is being used increasingly to study social interventions where context plays an important role in determining outcomes. This study further enhances the value of realist evaluations by incorporating a social network analysis component to quantify the structural context associated with CoPs. By identifying key mechanisms and contexts that optimise the effectiveness of CoPs, this study will contribute to creating a framework that will guide future establishment and evaluation of CoPs in healthcare.

  7. The Ontology of Interactive Kinds

    Directory of Open Access Journals (Sweden)

    Hauswald Rico

    2016-08-01

    Full Text Available This paper defends the notions of an interactive kind and a looping effect as features of social and human scientific classifications and aims to give a realist interpretation of them. I argue that interactive kinds can best be modeled as a special case of changing causal property cluster kinds. In order to do so, I develop a typology of looping effects according to the sort of entities that are affected, the main types of which are individual-looping, category-looping, and kind-looping. Based on this distinction, I identify interactive kinds as those causal property cluster kinds that are subjected to kind-looping.

  8. Didactic Contracts in Realistic Mathematics Education Teaching Practice in Indonesia: A lesson on addition

    DEFF Research Database (Denmark)

    Putra, Zetra Hainul

    This paper aims to investigate characterize features of didactic contracts in realistic mathematics education teaching practice in Indonesia in the case of a lesson on addition. We just focus on some episodes of 26 first grade students and a female teacher from SDN 197 Palembang learning combinat......This paper aims to investigate characterize features of didactic contracts in realistic mathematics education teaching practice in Indonesia in the case of a lesson on addition. We just focus on some episodes of 26 first grade students and a female teacher from SDN 197 Palembang learning...

  9. Toward the M(F)-theory embedding of realistic free-fermion models

    Energy Technology Data Exchange (ETDEWEB)

    Berglund, P. [Univ. of California, Santa Barbara, CA (United States). Institute for Theoretical Physics; Ellis, J. [CERN, Geneva (Switzerland). Theory Division; Faraggi, A.E. [Univ. of Florida, Gainesville, FL (United States). Institute for Fundamental Theory] [and others

    1998-03-01

    We construct a Landau-Ginzburg model with the same data and symmetries as a Z{sub 2} x Z{sub 2} orbifold that corresponds to a class of realistic free-fermion models. Within the class of interest, we show that this orbifolding connects between different Z{sub 2} x Z{sub 2} orbifold models and connects with the mirror symmetry. Our work suggests that duality symmetries previously discussed in the context of specific M and F theory compactifications may be extended to the special Z{sub 2} x Z{sub 2} orbifold that characterizes realistic free-fermion models.

  10. Ultra-realistic imaging advanced techniques in analogue and digital colour holography

    CERN Document Server

    Bjelkhagen, Hans

    2013-01-01

    Ultra-high resolution holograms are now finding commercial and industrial applications in such areas as holographic maps, 3D medical imaging, and consumer devices. Ultra-Realistic Imaging: Advanced Techniques in Analogue and Digital Colour Holography brings together a comprehensive discussion of key methods that enable holography to be used as a technique of ultra-realistic imaging.After a historical review of progress in holography, the book: Discusses CW recording lasers, pulsed holography lasers, and reviews optical designs for many of the principal laser types with emphasis on attaining th

  11. Active and realistic passive marijuana exposure tested by three immunoassays and GC/MS in urine

    Energy Technology Data Exchange (ETDEWEB)

    Mule, S.J.; Lomax, P.; Gross, S.J.

    1988-05-01

    Human urine samples obtained before and after active and passive exposure to marijuana were analyzed by immune kits (Roche, Amersham, and Syva) and gas chromatography/mass spectrometry (GC/MS). Seven of eight subjects were positive for the entire five-day test period with one immune kit. The latter correlated with GC/MS in 98% of the samples. Passive inhalation experiments under conditions likely to reflect realistic exposure resulted consistently in less than 10 ng/mL of cannabinoids. The 10-100-ng/mL cannabinoid concentration range essential for detection of occasional and moderate marijuana users is thus unaffected by realistic passive inhalation.

  12. A realist review of shared medical appointments: How, for whom, and under what circumstances do they work?

    Science.gov (United States)

    Kirsh, Susan R; Aron, David C; Johnson, Kimberly D; Santurri, Laura E; Stevenson, Lauren D; Jones, Katherine R; Jagosh, Justin

    2017-02-04

    Shared medical appointments (SMAs) are doctor-patient visits in which groups of patients are seen by one or more health care providers in a concurrent session. There is a growing interest in understanding the potential benefits of SMAs in various contexts to improve clinical outcomes and reduce healthcare costs. This study builds upon the existing evidence base that suggests SMAs are indeed effective. In this study, we explored how they are effective in terms of the underlying mechanisms of action and under what circumstances. Realist review methodology was used to synthesize the literature on SMAs, which included a broad search of 800+ published articles. 71 high quality primary research articles were retained to build a conceptual model of SMAs and 20 of those were selected for an in depth analysis using realist methodology (i.e.,middle-range theories and and context-mechanism-outcome configurations). Nine main mechanisms that serve to explain how SMAs work were theorized from the data immersion process and configured in a series of context-mechanism-outcome configurations (CMOs). These are: (1) Group exposure in SMAs combats isolation, which in turn helps to remove doubts about one's ability to manage illness; (2) Patients learn about disease self-management vicariously by witnessing others' illness experiences; (3) Patients feel inspired by seeing others who are coping well; (4) Group dynamics lead patients and providers to developing more equitable relationships; (5) Providers feel increased appreciation and rapport toward colleagues leading to increased efficiency; (6) Providers learn from the patients how better to meet their patients' needs; (7) Adequate time allotment of the SMA leads patients to feel supported; (8) Patients receive professional expertise from the provider in combination with first-hand information from peers, resulting in more robust health knowledge; and (9) Patients have the opportunity to see how the physicians interact with fellow

  13. Visualizing Our Options for Coastal Places: Exploring Realistic Immersive Geovisualizations as Tools for Inclusive Approaches to Coastal Planning and Management

    Directory of Open Access Journals (Sweden)

    Robert Newell

    2017-09-01

    Full Text Available Effective coastal planning is inclusive and incorporates the variety of user needs, values and interests associated with coastal environments. Realistic, immersive geographic visualizations, i.e., geovisualizations, can serve as potentially powerful tools for facilitating such planning because they can provide diverse groups with vivid understandings of how they would feel about certain management outcomes or impacts if transpired in real places. However, the majority of studies in this area have focused on terrestrial environments, and research on applications of such tools in the coastal and marine contexts is in its infancy. The current study aims to advance such research by examining the potential a land-to-sea geovisualization has to serve as a tool for inclusive coastal planning efforts. The research uses Sidney Spit Park (BC, Canada as a study site, and a realistic, dynamic geovisualization of the park was developed (using Unity3D that allows users to interact with and navigate it through the first-person perspective. Management scenarios were developed based on discussions with Parks Canada, and these scenarios included fencing around vegetation areas, positioning of mooring buoys, and management of dog activity within the park. Scenarios were built into the geovisualization in a manner that allows users to toggle different options. Focus groups were then assembled, involving residents of the Capital Regional District (BC, Canada, and participants explored and provided feedback on the scenarios. Findings from the study demonstrate the geovisualization's usefulness for assessing certain qualities of scenarios, such as aesthetics and functionality of fencing options and potential viewshed impacts associated with different mooring boat locations. In addition, the study found that incorporating navigability into the geovisualization proved to be valuable for understanding scenarios that hold implications for the marine environment due to

  14. Towards realistic Holocene land cover scenarios: integration of archaeological, palynological and geomorphological records and comparison to global land cover scenarios.

    Science.gov (United States)

    De Brue, Hanne; Verstraeten, Gert; Broothaerts, Nils; Notebaert, Bastiaan

    2016-04-01

    Accurate and spatially explicit landscape reconstructions for distinct time periods in human history are essential for the quantification of the effect of anthropogenic land cover changes on, e.g., global biogeochemical cycles, ecology, and geomorphic processes, and to improve our understanding of interaction between humans and the environment in general. A long-term perspective covering Mid and Late Holocene land use changes is recommended in this context, as it provides a baseline to evaluate human impact in more recent periods. Previous efforts to assess the evolution and intensity of agricultural land cover in past centuries or millennia have predominantly focused on palynological records. An increasing number of quantitative techniques has been developed during the last two decades to transfer palynological data to land cover estimates. However, these techniques have to deal with equifinality issues and, furthermore, do not sufficiently allow to reconstruct spatial patterns of past land cover. On the other hand, several continental and global databases of historical anthropogenic land cover changes based on estimates of global population and the required agricultural land per capita have been developed in the past decennium. However, at such long temporal and spatial scales, reconstruction of past anthropogenic land cover intensities and spatial patterns necessarily involves many uncertainties and assumptions as well. Here, we present a novel approach that combines archaeological, palynological and geomorphological data for the Dijle catchment in the central Belgium Loess Belt in order to arrive at more realistic Holocene land cover histories. Multiple land cover scenarios (> 60.000) are constructed using probabilistic rules and used as input into a sediment delivery model (WaTEM/SEDEM). Model outcomes are confronted with a detailed geomorphic dataset on Holocene sediment fluxes and with REVEALS based estimates of vegetation cover using palynological data from

  15. Effective electric fields along realistic DTI-based neural trajectories for modelling the stimulation mechanisms of TMS.

    Science.gov (United States)

    De Geeter, N; Crevecoeur, G; Leemans, A; Dupré, L

    2015-01-21

    In transcranial magnetic stimulation (TMS), an applied alternating magnetic field induces an electric field in the brain that can interact with the neural system. It is generally assumed that this induced electric field is the crucial effect exciting a certain region of the brain. More specifically, it is the component of this field parallel to the neuron's local orientation, the so-called effective electric field, that can initiate neuronal stimulation. Deeper insights on the stimulation mechanisms can be acquired through extensive TMS modelling. Most models study simple representations of neurons with assumed geometries, whereas we embed realistic neural trajectories computed using tractography based on diffusion tensor images. This way of modelling ensures a more accurate spatial distribution of the effective electric field that is in addition patient and case specific. The case study of this paper focuses on the single pulse stimulation of the left primary motor cortex with a standard figure-of-eight coil. Including realistic neural geometry in the model demonstrates the strong and localized variations of the effective electric field between the tracts themselves and along them due to the interplay of factors such as the tract's position and orientation in relation to the TMS coil, the neural trajectory and its course along the white and grey matter interface. Furthermore, the influence of changes in the coil orientation is studied. Investigating the impact of tissue anisotropy confirms that its contribution is not negligible. Moreover, assuming isotropic tissues lead to errors of the same size as rotating or tilting the coil with 10 degrees. In contrast, the model proves to be less sensitive towards the not well-known tissue conductivity values.

  16. Numerical investigation of sand production under realistic reservoir/well flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nouri, A.; Kuru, E. [Alberta Univ., Edmonton, AB (Canada); Vaziri, H. [BP America USA (United States)

    2006-07-01

    The limitations of existing sand production prediction methods were discussed and a critical review of various sand production models was presented. A new numerical model embedded into ABAQUS was then developed to predict the onset and severity of sand production under realistic reservoir/well flow conditions. ABAQUS is a finite element program that simulates the interaction between fluid flow and mechanical deformation of a medium. The model makes it possible to predict critical drawdown leading to the onset of sanding as well as the rate of sand production in real time. It is based on the continuum mechanics approach for modeling the process of sanding as a function of many parameters that have an effect on sand production. These include a time-dependent coupled fluid flow and deformation analysis of the rock, material disaggregation, sand removal, and operational conditions such as drawdown, depletion, and water-cut. The model has been validated against sanding experiments conducted on hollow cylinder samples involving real time sand production measurements under various conditions. The samples were subjected to a gradual increase of axial and radial loadings under a single-phase flow condition. The Mohr-Coulomb model captured the mechanical response of the porous medium to the applied loading and seepage conditions. Modeling strain softening of the material was required in the simulation of sand production. Seepage drag forces tend to generate tensile stresses in a material that has gone through strain softening process and has lost its ability to carry any effective stresses. The results of the numerical modeling study were in good agreement with experimental data in terms of the operational conditions leading to the onset of sanding as well as an estimation of the sanding rate. The model presents a real-time evaluation of the ongoing alterations in the material at the wellface during the production and provides insight into the role of the various parameters

  17. A realistic approach of the quantum non-locality and their experimental consequences; Uma abordagem realistica da nao-localidade quantica e suas consequencias experimentais

    Energy Technology Data Exchange (ETDEWEB)

    Ryff, Luiz Carlos Bandeira

    1992-01-01

    A realistic approach to quantum nonlocality is proposed, and four experiments that can be used to test this approach, using pairs of correlated photons are discussed. The first experiment proposed would allow us to investigate the role of the interaction of a quantum system with a macroscopic apparatus (detector) in the so-called collapse of the state vector. The second would investigate the interaction with a polarizer. Following the line of the second, the third experiment raises questions concerning the partial collapse of the state vector. The fourth suggests ways of investigating some possible properties of the superluminal interaction needed to explain nonlocality according to realism. The extension of this approach to include pairs of photons produced via parametric down-conversion of light is discussed. (author). 57 refs, 19 figs.

  18. Wavelets-Computational Aspects of Sterian Realistic Approach to Uncertainty Principle in High Energy Physics: A Transient Approach

    Directory of Open Access Journals (Sweden)

    Cristian Toma

    2013-01-01

    Full Text Available This study presents wavelets-computational aspects of Sterian-realistic approach to uncertainty principle in high energy physics. According to this approach, one cannot make a device for the simultaneous measuring of the canonical conjugate variables in reciprocal Fourier spaces. However, such aspects regarding the use of conjugate Fourier spaces can be also noticed in quantum field theory, where the position representation of a quantum wave is replaced by momentum representation before computing the interaction in a certain point of space, at a certain moment of time. For this reason, certain properties regarding the switch from one representation to another in these conjugate Fourier spaces should be established. It is shown that the best results can be obtained using wavelets aspects and support macroscopic functions for computing (i wave-train nonlinear relativistic transformation, (ii reflection/refraction with a constant shift, (iii diffraction considered as interaction with a null phase shift without annihilation of associated wave, (iv deflection by external electromagnetic fields without phase loss, and (v annihilation of associated wave-train through fast and spatially extended phenomena according to uncertainty principle.

  19. CASCADE-IMEI: A learning environment of realistic mathematics for student teachers in Indonesia

    NARCIS (Netherlands)

    Zulkardi, Z.; Nieveen, N.M.

    2001-01-01

    This paper reports on the second phase of a four-year study which aims to develop a learning environment that supports prospective mathematics teachers learning realistic mathematics education (RME) in teacher education in Indonesia. The results suggest that by giving student teachers experiences in

  20. Developing a learning environment on realistic mathematics education for Indonesian student teachers

    NARCIS (Netherlands)

    Zulkardi, Z.

    2002-01-01

    The CASCADE-IMEI study was started to explore the role of a learning environment (LE) in assisting mathematics student teachers learning Realistic Mathematics Education (RME) as a new instructional approach in mathematics education in Indonesia. The LE for this study has been developed and evaluated

  1. A search engine for retrieval and inspection of events with 48 human actions in realistic videos

    NARCIS (Netherlands)

    Burghouts, G.J.; Penning, H.L.H. de; Hove, R.J.M. ten; Landsmeer, S.; Broek, S.P. van den; Hollander, R.J.M.; Hanckmann, P.; Kruithof, M.C.; Leeuwen, C.J. van; Korzec, S.; Bouma, H.; Schutte, K.

    2013-01-01

    The contribution of this paper is a search engine that recognizes and describes 48 human actions in realistic videos. The core algorithms have been published recently, from the early visual processing (Bouma, 2012), discriminative recognition (Burghouts, 2012) and textual description (Hankmann,

  2. Cognitive Holding Power, Fluid Intelligence, and Mathematical Achievement as Predictors of Children's Realistic Problem Solving

    Science.gov (United States)

    Xin, Ziqiang; Zhang, Li

    2009-01-01

    The present study explored whether first and second order cognitive holding power perceived by children in mathematical classrooms, fluid intelligence, and mathematical achievement predicted their performance on standard problems, and especially realistic problems. A sample of 119 Chinese 4-6th graders were administered the word problem test, the…

  3. Improvements on a simple muscle-based 3D face for realistic facial expressions

    NARCIS (Netherlands)

    Bui, T.D.; Heylen, Dirk K.J.; Nijholt, Antinus; Badler, N.; Thalmann, D.

    2003-01-01

    Facial expressions play an important role in face-to-face communication. With the development of personal computers capable of rendering high quality graphics, computer facial animation has produced more and more realistic facial expressions to enrich human-computer communication. In this paper, we

  4. Hardware-in-the-loop testing of wireless systems in realistic environments.

    Energy Technology Data Exchange (ETDEWEB)

    Burkholder, R. J. (Ohio State University ElectroScience Laboratory); Mariano, Robert J.; Gupta, I. J. (Ohio State University ElectroScience Laboratory); Schniter, P. (Ohio State University ElectroScience Laboratory)

    2006-06-01

    This document describes an approach for testing of wireless systems in realistic environments that include intentional as well as unintentional radio frequency interference. In the approach, signal generators along with radio channel simulators are used to carry out hardware-in-the-loop testing. The channel parameters are obtained independently via channel sounding measurements and/or EM simulations.

  5. Blending critical realist and emancipatory practice development methodologies: making critical realism work in nursing research.

    Science.gov (United States)

    Parlour, Randal; McCormack, Brendan

    2012-12-01

    This paper examines the efficacy of facilitation as a practice development intervention in changing practice within an Older Person setting and in implementing evidence into practice. It outlines the influences exerted by the critical realist paradigm in guiding emancipatory practice development activities and, in particular, how the former may be employed within an emancipatory practice development study to elucidate and increase understanding pertinent to causation and outcomes. The methodology is based upon an emancipatory practice development approach set within a realistic evaluation framework. This allows for systematic analysis of the social and contextual elements that influence the explication of outcomes associated with facilitation. The study is concentrated upon five practice development cycles, within which a sequence of iterative processes is integrated. The authors assert that combining critical realist and emancipatory processes offers a robust and practical method for translating evidence and implementing changes in practice, as the former affirms or falsifies the influence that emancipatory processes exert on attaining culture shift, and enabling transformation towards effective clinical practice. A new framework for practice development is proposed that establishes methodological coherency between emancipatory practice development and realistic evaluation. This augments the existing theoretical bases for both these approaches by contributing new theoretical and methodological understandings of causation. © 2011 Blackwell Publishing Ltd.

  6. Plasticity-modulated seizure dynamics for seizure termination in realistic neuronal models

    NARCIS (Netherlands)

    Koppert, M.M.J.; Kalitzin, S.; Lopes da Silva, F.H.; Viergever, M.A.

    2011-01-01

    In previous studies we showed that autonomous absence seizure generation and termination can be explained by realistic neuronal models eliciting bi-stable dynamics. In these models epileptic seizures are triggered either by external stimuli (reflex epilepsies) or by internal fluctuations. This

  7. Commentary: Can we obtain realistic HIV/AIDS estimates for India?

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 28; Issue 4. Commentary: Can we obtain realistic HIV/AIDS estimates for India? Arni S R Srinivasa Rao. Volume 28 Issue 4 June 2003 pp 367-369. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/jbsc/028/04/0367-0369 ...

  8. The Publishing House: From Being to Becoming--The Developmental Dimension in Realistic Work Environments

    Science.gov (United States)

    Boardman, Kay

    2010-01-01

    Purpose: The purpose of this paper is to suggest that the "skills" or "employability" agenda which has long been anathema to the Humanities disciplines need not be the threat it appears to represent. This paper aims to examine the concept of realistic work environments and their focus, not only the provision of hard and soft…

  9. Do absorption and realistic distraction influence performance of component task surgical procedure?

    NARCIS (Netherlands)

    Pluyter, J.R.; Buzink, S.N.; Rutkowski, A.F.; Jakimowicz, J.J.

    2009-01-01

    Background. Surgeons perform complex tasks while exposed to multiple distracting sources that may increase stress in the operating room (e.g., music, conversation, and unadapted use of sophisticated technologies). This study aimed to examine whether such realistic social and technological

  10. The tenants in the vineyard (GThom 65/Mark 12:1-12): A realistic ...

    African Journals Online (AJOL)

    ... of the tenants, the second part of the article focuses on a social-scientific reading of GThom 65 through the lens of patronage and clientism and that of honor and shame. Finally, the conclusions reached by the social-scientific reading are compared with Kloppenborg's realistic reading thereof. HTS Theological Studies Vol.

  11. Heterogeneous Anthropomorphic Phantoms with Realistic Dielectric Properties for Microwave Breast Imaging Experiments

    OpenAIRE

    Mashal, Alireza; Gao, Fuqiang; Hagness, Susan C.

    2011-01-01

    We present a technique for fabricating realistic breast phantoms for microwave imaging experiments. Using oil-in-gelatin dispersions that mimic breast tissue dielectric properties at microwave frequencies, we constructed four heterogeneous phantoms spanning the full range of volumetric breast densities. We performed CT scans and dielectric properties measurements to characterize each phantom.

  12. Locating Starting Points in Differential Equations: A Realistic Mathematics Education Approach.

    Science.gov (United States)

    Rasmussen, Chris L.; King, Karen D.

    2000-01-01

    Reports on ongoing developmental research efforts to adapt the instructional design perspective of Realistic Mathematics Education (RME) to learning and teaching of collegiate mathematics using differential equations as a specific case. Focuses on the RME design heuristic of guided reinvention as a means to locate the starting point for an…

  13. A virtual auditory environment for investigating the auditory signal processing of realistic sounds

    DEFF Research Database (Denmark)

    Favrot, Sylvain Emmanuel; Buchholz, Jörg

    2008-01-01

    the VAE development, special care was taken in order to achieve a realistic auditory percept and to avoid “artifacts” such as unnatural coloration. The performance of the VAE has been evaluated and optimized on a 29 loudspeaker setup using both objective and subjective measurement techniques....

  14. Combining Campbell Standards and the Realist Evaluation Approach: The Best of Two Worlds?

    Science.gov (United States)

    van der Knaap, Leontien M.; Leeuw, Frans L.; Bogaerts, Stefan; Nijssen, Laura T. J.

    2008-01-01

    This article presents an approach to systematic reviews that combines the Campbell Collaboration Crime and Justice standards and the realist notion of contexts-mechanisms-outcomes (CMO) configurations. Both approaches have their advantages and drawbacks, and the authors will make a case for combining both approaches to profit from their advantages…

  15. A Social Realist Perspective on Student Learning in Higher Education: The Morphogenesis of Agency

    Science.gov (United States)

    Case, Jennifer M.

    2015-01-01

    Contemporary critiques of student learning research call for new theoretical and methodological approaches. This article proposes a social realist approach to this research, using the morphogenetic theory of sociologist Margaret Archer. The applicability of this approach is demonstrated by reference to an empirical study of engineering students at…

  16. Simulation of size-dependent aerosol deposition in a realistic model of the upper human airways

    NARCIS (Netherlands)

    Frederix, E.M.A.; Kuczaj, Arkadiusz K.; Nordlund, Markus; Belka, M.; Lizal, F.; Elcner, J.; Jicha, M.; Geurts, Bernardus J.

    An Eulerian internally mixed aerosol model is used for predictions of deposition inside a realistic cast of the human upper airways. The model, formulated in the multi-species and compressible framework, is solved using the sectional discretization of the droplet size distribution function to

  17. Depictions and Gaps: Portrayal of U.S. Poverty in Realistic Fiction Children's Picture Books

    Science.gov (United States)

    Kelley, Jane E.; Darragh, Janine J.

    2011-01-01

    Researchers conducted a critical multicultural analysis of 58 realistic fiction children's picture books that portray people living in poverty and compared these depictions to recent statistics from the United States Census Bureau. The picture books were examined for the following qualities: main character, geographic locale and time era, focal…

  18. A Realistic View of Aging: A Model for Teaching Future Generations. Final Report.

    Science.gov (United States)

    Lucchino, Ronald

    This final project report examines how to successfully develop a national approach for the infusion of aging content into the K-12 grade curricula. As the U.S. society is "graying," the students in schools should be exposed to aging information on the increasing responsibilities for the care of aging family members with a realistic view of their…

  19. Cold and hot cognition: quantum probability theory and realistic psychological modeling.

    Science.gov (United States)

    Corr, Philip J

    2013-06-01

    Typically, human decision making is emotionally "hot" and does not conform to "cold" classical probability (CP) theory. As quantum probability (QP) theory emphasises order, context, superimposition states, and nonlinear dynamic effects, one of its major strengths may be its power to unify formal modeling and realistic psychological theory (e.g., information uncertainty, anxiety, and indecision, as seen in the Prisoner's Dilemma).

  20. Blending critical realist and emancipatory practice development methodologies: making critical realism work in nursing research.

    LENUS (Irish Health Repository)

    Parlour, Randal

    2012-12-01

    This paper examines the efficacy of facilitation as a practice development intervention in changing practice within an Older Person setting and in implementing evidence into practice. It outlines the influences exerted by the critical realist paradigm in guiding emancipatory practice development activities and, in particular, how the former may be employed within an emancipatory practice development study to elucidate and increase understanding pertinent to causation and outcomes. The methodology is based upon an emancipatory practice development approach set within a realistic evaluation framework. This allows for systematic analysis of the social and contextual elements that influence the explication of outcomes associated with facilitation. The study is concentrated upon five practice development cycles, within which a sequence of iterative processes is integrated. The authors assert that combining critical realist and emancipatory processes offers a robust and practical method for translating evidence and implementing changes in practice, as the former affirms or falsifies the influence that emancipatory processes exert on attaining culture shift, and enabling transformation towards effective clinical practice. A new framework for practice development is proposed that establishes methodological coherency between emancipatory practice development and realistic evaluation. This augments the existing theoretical bases for both these approaches by contributing new theoretical and methodological understandings of causation.

  1. Realistic simulation of laser range finder behavior in a smoky environment

    NARCIS (Netherlands)

    Formsma, O.; Dijkshoorn, N.; van Noort, S.; Visser, A.; Ruiz-del-Solar, J.; Chown, E.; Plöger, P.G.

    2011-01-01

    The Urban Search and Rescue Simulation used for RoboCup lacks realistic response of laser range finders on smoke. In this paper, the behavior of a Hokuyo and Sick laser range finder in a smoky environment is studied. The behavior of the lasers is among others a function of the visibility level, and

  2. NETMORPH: a framework for the stochastic generation of large scale neuronal networks with realistic neuron morphologies

    NARCIS (Netherlands)

    Koene, R.A.; Tijms, B.; van Hees, P.; Postma, F.; de Ridder, A.; Ramakers, G.J.A.; van Pelt, J.; van Ooyen, A.

    2009-01-01

    We present a simulation framework, called NETMORPH, for the developmental generation of 3D large-scale neuronal networks with realistic neuron morphologies. In NETMORPH, neuronal morphogenesis is simulated from the perspective of the individual growth cone. For each growth cone in a growing axonal

  3. Assessing Outcomes of a Realistic Major Preview in an Introductory Sport Management Course

    Science.gov (United States)

    Pierce, David; Wanless, Elizabeth; Johnson, James

    2014-01-01

    This paper assessed the outcomes of a field experience assignment (FEA) in an introductory sport management course designed as a realistic major preview. Student learning outcomes assessed were commitment to the major, intent to pursue the major, expectation of a career in sports, and perceived preparation for a career in sports. A…

  4. Developing a realistic-prototyping road user cost evaluation tool for FDOT.

    Science.gov (United States)

    2008-12-31

    The objective of this project is to develop a realistic-prototyping RUC (Road User Cost) calculation tool that is userfriendly : and utilizing limited number of data inputs that are easy to use. The tool can help engineers to estimate RUC on : specif...

  5. Order Matters: Sequencing Scale-Realistic Versus Simplified Models to Improve Science Learning

    Science.gov (United States)

    Chen, Chen; Schneps, Matthew H.; Sonnert, Gerhard

    2016-10-01

    Teachers choosing between different models to facilitate students' understanding of an abstract system must decide whether to adopt a model that is simplified and striking or one that is realistic and complex. Only recently have instructional technologies enabled teachers and learners to change presentations swiftly and to provide for learning based on multiple models, thus giving rise to questions about the order of presentation. Using disjoint individual growth modeling to examine the learning of astronomical concepts using a simulation of the solar system on tablets for 152 high school students (age 15), the authors detect both a model effect and an order effect in the use of the Orrery, a simplified model that exaggerates the scale relationships, and the True-to-scale, a proportional model that more accurately represents the realistic scale relationships. Specifically, earlier exposure to the simplified model resulted in diminution of the conceptual gain from the subsequent realistic model, but the realistic model did not impede learning from the following simplified model.

  6. Realists, Radicals, and Rainbows. The Twenty-Eighth Amy Morris Homans Lecture 1994.

    Science.gov (United States)

    Bennett, Roberta S.

    1995-01-01

    Challenges physical education professionals to be realists who name the conditions around them that divide according to group identity and thus perpetuate injustice; to be radicals who work to change conditions; and to build and follow a rainbow path to a future where social justice, human rights, and the human condition are first priorities. (JB)

  7. CASCADE-IMEI: Web site support for student teachers learning Realistic Mathematics Education (RME) in Indonesia

    NARCIS (Netherlands)

    Zulkardi, Z.; Nieveen, N.M.

    2001-01-01

    CASCADE-IMEI is a learning environment in the form of a face-to-face course and a web site (www.cascadeimei.com) which aims to support student teachers in Indonesia to learn Realistic Mathematics Education (RME). RME is an instructional theory in mathematics education that was originally developed

  8. Education in the Anthropocene: Ethico-Moral Dimensions and Critical Realist Openings

    Science.gov (United States)

    Olvitt, Lausanne Laura

    2017-01-01

    Human-induced changes in planetary bio-geo-chemical processes have tipped earth into a newly-proposed geological epoch: the Anthropocene, which places moral and ethical demands on people regarding who should take responsibility for the well-being of people and planet, how, and why. Drawing generally on critical realist ontology, and more…

  9. Exploring effective interactions through transition charge density ...

    Indian Academy of Sciences (India)

    Thus the combined result leads to desired experimental behaviour of small peak inside and large peak at the surface. ... treating them simultaneously on equal footing. The two-body Hamiltonian H is given by .... probabilities. The realistic interaction for the f–p shell nuclei was constructed by. Kuo and Brown [7] and put to ...

  10. Use of sensors to deal with uncertainty in realistic robotic environments

    Science.gov (United States)

    Cervera, Enrique; del Pobil, Angel P.; Marta, Edward; Serna, Miguel A.

    1995-04-01

    This work is an application of Kohonen's self-organizing feature maps, to deal with uncertainty in realistic robotic environments. The neural network is fed with the signals of a force sensor attached to the wrist of the robot arm. The learning process consists of two phases: a training phase and a labeling phase. After training, the clusters of the map are associated to contact states. There are potential uncertainties in the positions of the elements, which cause error situations, like incorrect grasping of a piece or bad insertions. The error situations can be associated with clusters in the network. As a result of the application of this learning scheme, we can state that Kohonen's self-organizing feature maps are well suited for dealing with uncertainty in realistic robotic environments, particularly robot pick-and-place operations. They are easy to apply and powerful, and are a step towards the solution of more complex intelligent tasks.

  11. UE4Sim: A Photo-Realistic Simulator for Computer Vision Applications

    KAUST Repository

    Mueller, Matthias

    2017-08-19

    We present a photo-realistic training and evaluation simulator (UE4Sim) with extensive applications across various fields of computer vision. Built on top of the Unreal Engine, the simulator integrates full featured physics based cars, unmanned aerial vehicles (UAVs), and animated human actors in diverse urban and suburban 3D environments. We demonstrate the versatility of the simulator with two case studies: autonomous UAV-based tracking of moving objects and autonomous driving using supervised learning. The simulator fully integrates both several state-of-the-art tracking algorithms with a benchmark evaluation tool and a deep neural network (DNN) architecture for training vehicles to drive autonomously. It generates synthetic photo-realistic datasets with automatic ground truth annotations to easily extend existing real-world datasets and provides extensive synthetic data variety through its ability to reconfigure synthetic worlds on the fly using an automatic world generation tool.

  12. Toward realistic pursuit-evasion using a roadmap-based approach

    KAUST Repository

    Rodriguez, Samuel

    2011-05-01

    In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. Our approach can be applied to more realistic scenarios than are typically studied in most previous work, including agents moving in 3D environments such as terrains, multi-story buildings, and dynamic environments. We also support more realistic three-dimensional visibility computations that allow evading agents to hide in crowds or behind hills. We demonstrate the utility of this approach on mobile robots and in simulation for a variety of scenarios including pursuit-evasion and tag on terrains, in multi-level buildings, and in crowds. © 2011 IEEE.

  13. Towards Behaviorly Realistic Simulations of the Stock Market Traders with a Soul

    CERN Document Server

    Solomon, S

    1999-01-01

    The price fluctuations in the financial markets are the result of the individual operations by many individual investors. However for many decades the finacial theory did not use directly this "microscopic representation". The difficulties preventing it were multiple but the main two are being solved recently with the advent of modern computer technology: - massive detailed data on the individual market operations became available. - "microscopic simulations" of the stock markets in terms of their individual participating agents allow a very realistic treatment of the problem. Consequently, we are now able to confront real market data with the results of simulating "microscopic" realistic models which include any desired features in the investors behavior: departures from rationality, herding effects, heterogenous investor-specific trading strategies etc. In this way we propose to understand, explain and may be predict the macroscopic market behavior.

  14. Rehand: Realistic electric prosthetic hand created with a 3D printer.

    Science.gov (United States)

    Yoshikawa, Masahiro; Sato, Ryo; Higashihara, Takanori; Ogasawara, Tsukasa; Kawashima, Noritaka

    2015-01-01

    Myoelectric prosthetic hands provide an appearance with five fingers and a grasping function to forearm amputees. However, they have problems in weight, appearance, and cost. This paper reports on the Rehand, a realistic electric prosthetic hand created with a 3D printer. It provides a realistic appearance that is same as the cosmetic prosthetic hand and a grasping function. A simple link mechanism with one linear actuator for grasping and 3D printed parts achieve low cost, light weight, and ease of maintenance. An operating system based on a distance sensor provides a natural operability equivalent to the myoelectric control system. A supporter socket allows them to wear the prosthetic hand easily. An evaluation using the Southampton Hand Assessment Procedure (SHAP) demonstrated that an amputee was able to operate various objects and do everyday activities with the Rehand.

  15. Analysis of a realistic and idealized dispersion compensating photonic crystal fiber Raman Amplifier

    DEFF Research Database (Denmark)

    Varshney, S.K.; Saitoh, K.; Koshiba, M.

    2007-01-01

    In the present paper, the highly efficient Raman amplification properties of a realistic and idealized dispersion compensating photonic crystal fiber (DCPCF) are described numerically. We have used an accurate full-vectorial finite element modal solver with hybrid curvilinear edge/nodal elements...... and anisotropic perfectly matched layers for an accurate modal characterization of the realistic as well as idealized DCPCF. A good agreement is observed between numerically evaluated and experimentally [P.J. Roberts, B.J. Mangan, H. Sabert, F. Couny, et al., J. Opt. Fiber Commun. Rep. 2 (2005) 435-461] measured...... dispersion values. A high peak Raman gain efficiency of 10.5 W-¹?km-¹ is obtained at 13.1 THz frequency shift for a 1455 nm depolarized pump. A DCPCF module of 1-km length can compensate for the dispersion accumulated over 70-km of conventional single mode fiber link with a residual dispersion of +/-50 ps...

  16. Realistic teenage fiction with a sexrelated theme: Readers’ responses to Slinger-slinger by Francois Bloemhof

    Directory of Open Access Journals (Sweden)

    M.N. Wiggill

    2004-07-01

    Full Text Available Francois Bloemhof submitted his novel for teenagers, “Slinger-slinger” for the Sanlam competition for youth fiction in 1996. Eventually this prizewinner in the beginners’ category was published in 1997. The main theme of “Slinger-slinger” is the sexual awakening and identity of teenagers. A study was undertaken to obtain the opinions of teenage readers about the success of “Slinger-slinger” as a whole, as well as to gauge the success of integrating sexual aspects in this novel. The study also served to obtain information about the reading needs of teenage readers with regard to realistic teenage fiction and teenage fiction with a sex-related theme. The findings of the study underlying this article indicated that the participating teenage readers regarded “Slinger-slinger” as successful and interesting, and that they would like to read more realistic Afrikaans teenage fiction such as “Slinger-slinger”.

  17. Realistic reference adult and paediatric phantom series for internal and external dosimetry

    Science.gov (United States)

    Stabin, M. G.; Emmons, M. A.; Segars, W. P.; Fernald, M. J.

    2012-01-01

    A new generation of realistic, image-based anthropomorphic phantoms has been developed based on the reference masses and organ definitions given in the International Commission on Radiological Protection Publication 89. Specific absorbed fractions for internal radiation sources have been calculated for photon and electron sources for many body organs. Values are similar to those from the previous generation of ‘stylized’ (mathematical equation-based) models, but some differences are seen, particularly at low particle or photon energies, due to the more realistic organ geometries, with organs generally being closer together, and with some touching and overlapping. Extension of this work, to use these phantoms in Monte Carlo radiation transport simulation codes with external radiation sources, is an important area of investigation that should be undertaken. PMID:22128359

  18. Interactive highly realistic virtual reality as a tool for understanding the genesis and treatment of psychotic symptoms.

    Science.gov (United States)

    Zányi, Eva; Selmanovic, Elmedin; Broome, Matthew; Czanner, Silvester; Birchwood, Max; Chalmers, Alan; Singh, Swaran

    2009-01-01

    Schizophrenia can be a devastating lifelong psychotic disorder with a poor prognosis. National guidelines in the UK recommend the provision of cognitive behavioral therapy (CBT) to all those suffering with psychotic disorders, but there is a lack of trained therapists in the UK able to provide such a treatment. Developing high quality automated technologies that can serve as an adjunct to conventional CBT should enhance the provision of this therapy, and increase the efficiency of the therapists in practice. The latter will occur by enabling alternate professionals to aid in the delivery of therapy, to enable behavioral experiments to be conducted in the clinic, and for sessions to be recorded and re-played such that the patient can deliver therapy to him or herself. As such the system will enable patients to become experts in, and providers of, their own treatment and decrease the number of sessions needed to be led by a trained CBT therapist. A key feature of any such system is the level of realism required to ensure a compelling session in which the user is not adversely affected by the system itself. This paper presents a high-fidelity virtual environment to help better understand the environmental triggers for psychosis.

  19. Intelligible design a realistic approach to the philosophy and history of science

    CERN Document Server

    Gonzalo, Julio A

    2014-01-01

    This book provides realistic answers to hotly debated scientific topics: Science is about quantitative aspects of natural realities (physical, chemical, biological) but it is the result of human intellectual inquiry and therefore not "per se" materialistic. This book, with contributions from experts in physics, cosmology, mathematics, engineering, biology and genetics, covers timely and relevant topics such as the origin of the universe, the origin of life on Earth, the origin of man (intelligent life) and the origin of science.

  20. Development Considerations of AREVA NP Inc.'s Realistic LBLOCA Analysis Methodology

    OpenAIRE

    Martin, Robert P.; Larry D. O'Dell

    2008-01-01

    The AREVA NP Inc. realistic large-break loss-of-coolant-accident (LOCA) analysis methodology references the 1988 amended 10 CFR 50.46 allowing best-estimate calculations of emergency core cooling system performance. This methodology conforms to the code scaling, applicability, and uncertainty (CSAU) methodology developed by the Technical Program Group for the United States Nuclear Regulatory Commission in the late 1980s. In addition, several practical consi...

  1. Scalable generation of graph-state entanglement through realistic linear optics.

    Science.gov (United States)

    Bodiya, T P; Duan, L-M

    2006-10-06

    We propose a scheme for efficient construction of graph states using realistic linear optics, imperfect photon source, and single-photon detectors. For any many-body entanglement represented by tree-graph states, we prove that the overall preparation and detection efficiency scales nearly polynomially with the size of the graph, no matter how small the efficiencies for the photon source and the detectors.

  2. Application of ICA to realistically simulated (1)H-MRS data.

    Science.gov (United States)

    Kalyanam, Ravi; Boutte, David; Hutchison, Kent E; Calhoun, Vince D

    2015-07-01

    (1)H-MRS signals from brain tissues capture information on in vivo brain metabolism and neuronal biomarkers. This study aims to advance the use of independent component analysis (ICA) for spectroscopy data by objectively comparing the performance of ICA and LCModel in analyzing realistic data that mimics many of the known properties of in vivo data. This work identifies key features of in vivo (1)H-MRS signals and presents methods to simulate realistic data, using a basis set of 12 metabolites typically found in the human brain. The realistic simulations provide a much needed ground truth to evaluate performances of various MRS analysis methods. ICA is applied to collectively analyze multiple realistic spectra and independent components identified with our generative model to obtain ICA estimates. These same data are also analyzed using LCModel and the comparisons between the ground-truth and the analysis estimates are presented. The study also investigates the potential impact of modeling inaccuracies by incorporating two sets of model resonances in simulations. The simulated fid signals incorporating line broadening, noise, and residual water signal closely resemble the in vivo signals. Simulation analyses show that the resolution performances of both LCModel and ICA are not consistent across metabolites and that while ICA resolution can be improved for certain resonances, ICA is as effective as, or better than, LCModel in resolving most model resonances. The results show that ICA can be an effective tool in comparing multiple spectra and complements existing approaches for providing quantified estimates.

  3. Deep Generative Adversarial Neural Networks for Realistic Prostate Lesion MRI Synthesis

    OpenAIRE

    Kitchen, Andy; Seah, Jarrel

    2017-01-01

    Generative Adversarial Neural Networks (GANs) are applied to the synthetic generation of prostate lesion MRI images. GANs have been applied to a variety of natural images, is shown show that the same techniques can be used in the medical domain to create realistic looking synthetic lesion images. 16mm x 16mm patches are extracted from 330 MRI scans from the SPIE ProstateX Challenge 2016 and used to train a Deep Convolutional Generative Adversarial Neural Network (DCGAN) utilizing cutting edge...

  4. Effects of Defining Realistic Compositions of the Ocular Melanoma on Proton Therapy

    Directory of Open Access Journals (Sweden)

    Keshazare Sh

    2014-12-01

    Full Text Available Background: Recent studies in eye plaque brachytherapy have shown a considerable difference between the dosimetric results using water phantom and a model of human eye containing realistic materials. In spite of this fact, there is a lack of simulation studies based on such a model in proton therapy literatures. In the presented work, the effect of utilizing an eye model with ocular media on proton therapy is investigated using the MCNPX Monte Carlo Code. Methods: Two different eye models are proposed to study the effect of defining realistic materials on dose deposition due to utilizing pencil beam scanning (PBS method for proton therapy of ocular melanoma. The first model is filled with water, and the second one contains the realistic materials of tumor and vitreous. Spread out Bragg peaks (SOBP are created to cover a typical tumor volume. Moreover, isodose curves are figured in order to evaluate planar variations of absorbed dose in two models. Results: The results show that the maximum delivered dose in ocular media is approximately 12-32% more than in water phantom. Also it is found that using the optimized weighted beams in water phantom leads to disturbance of uniformity of SOBP in ocular media. Conclusion: Similar to the results reported in eye brachytherapy published papers, considering the ocular media in simulation studies leads to a more realistic assessment of sufficiency of the designed proton beam in tissue. This effect is of special importance in creating SOBP, as well as in delivered dose in the tumor boundaries in proton pencil beam scanning method.

  5. The Decadent City: Urban Space in Latin American Dirty Realist Fiction

    OpenAIRE

    Fudacz, Jamie Diane

    2012-01-01

    This dissertation explores the treatment of urban spaces in Latin American dirty realist fiction from the 1990's to the present, focusing on the works of Guillermo Fadanelli (Mexico), Fernando Vallejo (Colombia), and Pedro Juan Gutiérrez (Cuba). Whereas Fadanelli centers his works in the megalopolis of a Mexico City straining under the pressures of rapid modernization and development, Gutiérrez depicts a Havana crumbling during the economic crises of the Special Period, and Vallejo portrays...

  6. Emulation of realistic network traffic patterns on an eight-node data vortex interconnection network subsystem

    Science.gov (United States)

    Small, Benjamin A.; Shacham, Assaf; Bergman, Keren; Athikulwongse, Krit; Hawkins, Cory; Wills, D. Scott

    2004-11-01

    e demonstrate the feasibility of the data vortex interconnection network architecture for use in supercomputing by emulating realistic network traffic on an eight-node subnetwork. The evaluation workload uses memory accesses from the Barnes-Hut application in the SLPASH-2 parallel computing benchmark suite, which was extracted by using the M5 multiprocessor system simulator. We confirm that traffic is routed correctly and efficiently.

  7. Realistic Approach for Beam Dynamics Simulation with Synchrotron Radiation in High Energy Circular Lepton Colliders

    CERN Document Server

    Glukhov, S A

    2017-01-01

    In extremely high energy circular lepton colliders, correct consideration of synchrotron radiation is important for beam dynamics simulation. We developed a fast precise effective method to track particles in a realistic lattice when the radiation effects are distributed along the orbit. In the present paper we study an effect of decreasing dynamic aperture due to radiation from quadrupole lenses in the FCC-ee lepton collider.

  8. Comparison of Sigma-Point and Extended Kalman Filters on a Realistic Orbit Determination Scenario

    Science.gov (United States)

    Gaebler, John; Hur-Diaz. Sun; Carpenter, Russell

    2010-01-01

    Sigma-point filters have received a lot of attention in recent years as a better alternative to extended Kalman filters for highly nonlinear problems. In this paper, we compare the performance of the additive divided difference sigma-point filter to the extended Kalman filter when applied to orbit determination of a realistic operational scenario based on the Interstellar Boundary Explorer mission. For the scenario studied, both filters provided equivalent results. The performance of each is discussed in detail.

  9. In vitro measurement of ambient pressure changes using a realistic clinical setup

    DEFF Research Database (Denmark)

    Andersen, Klaus Scheldrup; Jensen, Jørgen Arendt

    2008-01-01

    In vitro measurement of ambient pressure changes using a realistic clinical setup Klaus Scheldrup Andersen and Jørgen Arendt Jensen Motivation and objective: Many attempts to find a non-invasive procedure to measure the local blood pressure have been made. In the last decade independent experiments...... correspondence with results by Shi et al 1999 and Adam et al 2005 who both used a receiver separated from the emitting single element transducer....

  10. RNA-seq mixology: designing realistic control experiments to compare protocols and analysis methods

    OpenAIRE

    Holik, Aliaksei Z.; Law, Charity W.; Liu, Ruijie; Wang, Zeya; Wang, Wenyi; Ahn, Jaeil; Asselin-Labat, Marie-Liesse; Gordon K. Smyth; Ritchie, Matthew E.

    2016-01-01

    Abstract Carefully designed control experiments provide a gold standard for benchmarking different genomics research tools. A shortcoming of many gene expression control studies is that replication involves profiling the same reference RNA sample multiple times. This leads to low, pure technical noise that is atypical of regular studies. To achieve a more realistic noise structure, we generated a RNA-sequencing mixture experiment using two cell lines of the same cancer type. Variability was a...

  11. The Effects of Realistic Mathematics Education on Students’ Math Self Reports in Fifth Grades Mathematics Course

    OpenAIRE

    Sebahat Yetim Karaca; Ali Özkaya

    2017-01-01

    The aim of this research is to analyze the effects of realistic mathematics education on students’ self-reports on the ‘numbers and operation’ unit of the 5th grades mathematics course. For this reason, two classes were randomly identified. After seeing that the groups were equivalent using the Achievement Test of Group Equivalency (ATGE), Achievement Test of Learning Domain (ATLD) and Mathematics Self-Report Inventory (MSRI) were applied to both groups. The application was continued for 7 we...

  12. Projected health effects of realistic dietary changes to address freshwater constraints in India: a modelling study.

    OpenAIRE

    Milner, J; Joy, EJM; Green, R; Harris, F; Aleksandrowicz, L; Agrawal, S; Smith, P; Haines, A; Dangour, AD

    2017-01-01

    Summary Background The availability of freshwater for irrigation in the Indian agricultural sector is expected to decline over the coming decades. This might have implications for food production in India, with subsequent effects on diets and health. We identify realistic and healthy dietary changes that could enhance the resilience of the Indian food system to future decreases in water availability. Methods In this modelling study, we optimised typical dietary patterns in an Indian populatio...

  13. Realism, Modernism and the Realistic Spirit: Diamond's Inheritance of Wittgenstein, Early and Late

    Directory of Open Access Journals (Sweden)

    Stephen Mulhall

    2012-11-01

    Full Text Available This paper argues that Cora Diamond's interpretation of Wittgenstein's early and later work, and her specific attempts to apply it in religious and ethical contexts, show a willingness to sacrifice elements of Wittgenstein's signature concepts to the demands of what she calls his 'realistic spirit'. The paper also argues that this willingness relates her project to a certain understanding of modernism in the arts.

  14. Analysis of the properties of SGRs and AXPs with realistic neutron star configurations

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Rafael C. R. de [ICRANet, Piazza della Repubblica 10, I-65122 Pescara (Italy); Coelho, Jaziel G. [Divisão de Astrofísica, Instituto Nacional de Pesquisas Espaciais, Avenida dos Astronautas 1758, 12227–010 São José dos Campos, SP (Brazil); Rueda, Jorge A.; Ruffini, Remo [ICRANet, Piazza della Repubblica 10, I-65122 Pescara (Italy); Dip. di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Rome (Italy); ICRANet-Rio, Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290–180 Rio de Janeiro (Brazil); Malheiro, Manuel [Departamento de Física, Instituto Tecnológico de Aeronáutica, São José dos Campos, 12228-900, SP (Brazil)

    2015-12-17

    We show that nine soft gamma repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) of the twenty three known sources can be described as rotation-powered canonical pulsars. To accomplish this we use realistic parameters of rotating neutron stars obtained from numerical integration of the self-consistent axisymmetric general relativistic equations of equilibrium. We present limits to the NS mass where the sources can be rotation-powered.

  15. Comparison of temporal realistic telecommunication base station exposure with worst-case estimation in two countries.

    Science.gov (United States)

    Mahfouz, Zaher; Verloock, Leen; Joseph, Wout; Tanghe, Emmeric; Gati, Azeddine; Wiart, Joe; Lautru, David; Hanna, Victor Fouad; Martens, Luc

    2013-12-01

    The influence of temporal daily exposure to global system for mobile communications (GSM) and universal mobile telecommunications systems and high speed downlink packet access (UMTS-HSDPA) is investigated using spectrum analyser measurements in two countries, France and Belgium. Temporal variations and traffic distributions are investigated. Three different methods to estimate maximal electric-field exposure are compared. The maximal realistic (99 %) and the maximal theoretical extrapolation factor used to extrapolate the measured broadcast control channel (BCCH) for GSM and the common pilot channel (CPICH) for UMTS are presented and compared for the first time in the two countries. Similar conclusions are found in the two countries for both urban and rural areas: worst-case exposure assessment overestimates realistic maximal exposure up to 5.7 dB for the considered example. In France, the values are the highest, because of the higher population density. The results for the maximal realistic extrapolation factor at the weekdays are similar to those from weekend days.

  16. Human Performance in a Realistic Instrument-Control Task during Short-Term Microgravity.

    Directory of Open Access Journals (Sweden)

    Fabian Steinberg

    Full Text Available Previous studies have documented the detrimental effects of microgravity on human sensorimotor skills. While that work dealt with simple, laboratory-type skills, we now evaluate the effects of microgravity on a complex, realistic instrument-control skill. Twelve participants controlled a simulated power plant during the short-term microgravity intervals of parabolic flight as well as during level flight. To this end they watched multiple displays, made strategic decisions and used multiple actuators to maximize their virtual earnings from the power plant. We quantified control efficiency as the participants' net earnings (revenue minus expenses, motor performance as hand kinematics and dynamics, and stress as cortisol level, self-assessed mood and self-assessed workload. We found that compared to normal gravity, control efficiency substantially decreased in microgravity, hand velocity slowed down, and cortisol level and perceived physical strain increased, but other stress and motor scores didn't change. Furthermore, control efficiency was not correlated with motor and stress scores. From this we conclude that realistic instrument control was degraded in short-term microgravity. This degradation can't be explained by the motor and/or stress indicators under study, and microgravity affected motor performance differently in our complex, realistic skill than in the simple, laboratory-type skills of earlier studies.

  17. Human Performance in a Realistic Instrument-Control Task during Short-Term Microgravity.

    Science.gov (United States)

    Steinberg, Fabian; Kalicinski, Michael; Dalecki, Marc; Bock, Otmar

    2015-01-01

    Previous studies have documented the detrimental effects of microgravity on human sensorimotor skills. While that work dealt with simple, laboratory-type skills, we now evaluate the effects of microgravity on a complex, realistic instrument-control skill. Twelve participants controlled a simulated power plant during the short-term microgravity intervals of parabolic flight as well as during level flight. To this end they watched multiple displays, made strategic decisions and used multiple actuators to maximize their virtual earnings from the power plant. We quantified control efficiency as the participants' net earnings (revenue minus expenses), motor performance as hand kinematics and dynamics, and stress as cortisol level, self-assessed mood and self-assessed workload. We found that compared to normal gravity, control efficiency substantially decreased in microgravity, hand velocity slowed down, and cortisol level and perceived physical strain increased, but other stress and motor scores didn't change. Furthermore, control efficiency was not correlated with motor and stress scores. From this we conclude that realistic instrument control was degraded in short-term microgravity. This degradation can't be explained by the motor and/or stress indicators under study, and microgravity affected motor performance differently in our complex, realistic skill than in the simple, laboratory-type skills of earlier studies.

  18. Towards building a photo-realistic virtual human face for craniomaxillofacial diagnosis and treatment planning.

    Science.gov (United States)

    Ayoub, A F; Xiao, Y; Khambay, B; Siebert, J P; Hadley, D

    2007-05-01

    The aim of this investigation was to assess the feasibility of building a virtual human face digitally by superimposing a photo-realistic three-dimensional (3D) soft-tissue surface on bone in the correct relationship and evaluating the registration errors associated with this method. The 3D soft-tissue surface of the face was captured using a fast stereophotogrammetry method and the underlying bone was recorded using a 3D computed tomography (CT) scanner. Using the Procrustes registration method, the outer surface of the 3D CT scan and the photo-realistic soft-tissue surfaces were merged into a single Virtual Reality Modelling Language (VRML) file and displayed using a standard VRML viewer. Quantitative measurements of registration errors were calculated in the reconstructed human head models using the signed closest point distance from the photo-realistic skin surface to the transformed CT skin surface. The registration errors between most parts of the aligned surfaces were within +/-1.5mm. The errors were relatively large around the eyebrows, eyelids and cheeks. Simultaneous recording of the face and skull may reduce this error.

  19. Protocol: realist synthesis of the impact of unemployment insurance policies on poverty and health.

    Science.gov (United States)

    Molnar, Agnes; O'Campo, Patricia; Ng, Edwin; Mitchell, Christiane; Muntaner, Carles; Renahy, Emilie; St John, Alexander; Shankardass, Ketan

    2015-02-01

    Unemployment insurance is an important social protection policy that buffers unemployed workers against poverty and poor health. Most unemployment insurance studies focus on whether increases in unemployment insurance generosity are predictive of poverty and health outcomes. Less work has used theory-driven approaches to understand and explain how and why unemployment insurance works, for whom, and under what circumstances. Given this, we present a realist synthesis protocol that seeks to unpack how contextual influences trigger relevant mechanisms to generate poverty and health outcomes. In this protocol, we conceptualize unemployment insurance as a key social protection policy; provide a supporting rationale on the need for a realist synthesis; and describe our process on identifying context-mechanism-outcome pattern configurations. Six methodological steps are described: initial theory development, search strategy; selection and appraisal of documents; data extraction; analysis and synthesis process; and presentation and dissemination of revised theory. Our forthcoming realist synthesis will be the first to build and test theory on the intended and unintended outcomes of unemployment insurance policies. Anticipated findings will allow policymakers to move beyond 'black box' approaches to consider 'mechanism-based' explanations that explicate the logic on how and why unemployment insurance matters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. "easyMine" – realistic and systematic mine detection simulation tooltion

    Directory of Open Access Journals (Sweden)

    U. Böttger

    2004-01-01

    Full Text Available Mine detection is to date mainly performed with metal detectors, although new methods for UXO detection are explored worldwide. The main problem for the mine detection to date is, that there exist some ideas of which sensor combinations could yield a high score, but until now there is no systematic analysis of mine detection methods together with realistic environmental conditions to conclude on a physically and technically optimized sensor combination. This gap will be removed by a project “easyMine" (Realistic and systematic Mine Detection Simulation Tool which will result in a simulation tool for optimizing land mine detection in a realistic mine field. The project idea for this software tool is presented, that will simulate the closed chain of mine detection, including the mine in its natural environment, the sensor, the evaluation and application of the measurements by an user. The tool will be modularly designed. Each chain link will be an independent, exchangeable sub- module and will describe a stand alone part of the whole mine detection procedure. The advantage of the tool will be the evaluation of very different kinds of sensor combinations in relation of their real potential for mine detection. Three detection methods (metal detector, GPR and imaging IR-radiometry will be explained to be introduced into the easyMine software tool in a first step. An actual example for land mine detection problem will be presented and approaches for solutions with easyMine will be shown.

  1. High accuracy mantle convection simulation through modern numerical methods - II: realistic models and problems

    Science.gov (United States)

    Heister, Timo; Dannberg, Juliane; Gassmöller, Rene; Bangerth, Wolfgang

    2017-08-01

    Computations have helped elucidate the dynamics of Earth's mantle for several decades already. The numerical methods that underlie these simulations have greatly evolved within this time span, and today include dynamically changing and adaptively refined meshes, sophisticated and efficient solvers, and parallelization to large clusters of computers. At the same time, many of the methods - discussed in detail in a previous paper in this series - were developed and tested primarily using model problems that lack many of the complexities that are common to the realistic models our community wants to solve today. With several years of experience solving complex and realistic models, we here revisit some of the algorithm designs of the earlier paper and discuss the incorporation of more complex physics. In particular, we re-consider time stepping and mesh refinement algorithms, evaluate approaches to incorporate compressibility, and discuss dealing with strongly varying material coefficients, latent heat, and how to track chemical compositions and heterogeneities. Taken together and implemented in a high-performance, massively parallel code, the techniques discussed in this paper then allow for high resolution, 3-D, compressible, global mantle convection simulations with phase transitions, strongly temperature dependent viscosity and realistic material properties based on mineral physics data.

  2. A GPU Tool for Efficient, Accurate, and Realistic Simulation of Cone Beam CT Projections

    CERN Document Server

    Jia, Xun; Cervino, Laura; Folkerts, Michael; Jiang, Steve B

    2012-01-01

    Simulation of x-ray projection images plays an important role in cone beam CT (CBCT) related research projects. A projection image contains primary signal, scatter signal, and noise. It is computationally demanding to perform accurate and realistic computations for all of these components. In this work, we develop a package on GPU, called gDRR, for the accurate and efficient computations of x-ray projection images in CBCT under clinically realistic conditions. The primary signal is computed by a tri-linear ray-tracing algorithm. A Monte Carlo (MC) simulation is then performed, yielding the primary signal and the scatter signal, both with noise. A denoising process is applied to obtain a smooth scatter signal. The noise component is then obtained by combining the difference between the MC primary and the ray-tracing primary signals, and the difference between the MC simulated scatter and the denoised scatter signals. Finally, a calibration step converts the calculated noise signal into a realistic one by scali...

  3. Fully kinetic 3D simulations of the Hermean magnetosphere under realistic conditions: a new approach

    Science.gov (United States)

    Amaya, Jorge; Gonzalez-Herrero, Diego; Lembège, Bertrand; Lapenta, Giovanni

    2017-04-01

    Simulations of the magnetosphere of planets are usually performed using the MHD and the hybrid approaches. However, these two methods still rely on approximations for the computation of the pressure tensor, and require the neutrality of the plasma at every point of the domain by construction. These approximations undermine the role of electrons on the emergence of plasma features in the magnetosphere of planets. The high mobility of electrons, their characteristic time and space scales, and the lack of perfect neutrality, are the source of many observed phenomena in the magnetospheres, including the turbulence energy cascade, the magnetic reconnection, the particle acceleration in the shock front and the formation of current systems around the magnetosphere. Fully kinetic codes are extremely demanding of computing time, and have been unable to perform simulations of the full magnetosphere at the real scales of a planet with realistic plasma conditions. This is caused by two main reasons: 1) explicit codes must resolve the electron scales limiting the time and space discretisation, and 2) current versions of semi-implicit codes are unstable for cell sizes larger than a few Debye lengths. In this work we present new simulations performed with ECsim, an Energy Conserving semi-implicit method [1], that can overcome these two barriers. We compare the solutions obtained with ECsim with the solutions obtained by the classic semi-implicit code iPic3D [2]. The new simulations with ECsim demand a larger computational effort, but the time and space discretisations are larger than those in iPic3D allowing for a faster simulation time of the full planetary environment. The new code, ECsim, can reach a resolution allowing the capture of significant large scale physics without loosing kinetic electron information, such as wave-electron interaction and non-Maxwellian electron velocity distributions [3]. The code is able to better capture the thickness of the different boundary

  4. Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2011-01-21

    In their Contributed Article, Nyein et al. (1,2) present numerical simulations of blast waves interacting with a helmeted head and conclude that a face shield may significantly mitigate blast induced traumatic brain injury (TBI). A face shield may indeed be important for future military helmets, but the authors derive their conclusions from a much smaller explosion than typically experienced on the battlefield. The blast from the 3.16 gm TNT charge of (1) has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 10 atm, 0.25 ms, and 3.9 psi-ms at the front of the head (14 cm from charge), and 1.4 atm, 0.32 ms, and 1.7 psi-ms at the back of a typical 20 cm head (34 cm from charge). The peak pressure of the wave decreases by a factor of 7 as it traverses the head. The blast conditions are at the threshold for injury at the front of the head, but well below threshold at the back of the head (4). The blast traverses the head in 0.3 ms, roughly equal to the positive phase duration of the blast. Therefore, when the blast reaches the back of the head, near ambient conditions exist at the front. Because the headform is so close to the charge, it experiences a wave with significant curvature. By contrast, a realistic blast from a 2.2 kg TNT charge ({approx} an uncased 105 mm artillery round) is fatal at an overpressure of 10 atm (4). For an injury level (4) similar to (1), a 2.2 kg charge has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 2.1 atm, 2.3 ms, and 18 psi-ms at the front of the head (250 cm from charge), and 1.8 atm, 2.5 ms, and 16.8 psi-ms at the back of the head (270 cm from charge). The peak pressure decreases by only a factor of 1.2 as it traverses the head. Because the 0.36 ms traversal time is much smaller than the positive phase duration, pressures on the head become relatively uniform when the blast reaches the back of the head. The larger standoff implies

  5. Undertaking a Collaborative Rapid Realist Review to Investigate What Works in the Successful Implementation of a Frail Older Person's Pathway.

    LENUS (Irish Health Repository)

    2018-01-25

    We addressed the research question "what factors enable the successful development and implementation of a frail older person\\'s pathway within the acute setting". A rapid realist review (RRR) was conducted by adopting the RAMESES standards. We began with a sample of 232 articles via database searches supplemented with 94 additional records including inputs from a twitter chat and a hospital site visit. Our final sample consisted of 18 documents. Following review and consensus by an expert panel we identified a conceptual model of context-mechanism-(resources)-outcomes. There was overall agreement frailty should be identified at the front door of the acute hospital. Significant challenges identified related to organisational boundaries both within the acute setting and externally, the need to shift outcomes to patient orientated ones, to support staff to sustain the pathway by providing ongoing education and by providing role clarity. RRRs can support research such as the systematic approach to improving care for frail older adults (SAFE) study by producing accounts of what works based on a wide range of sources and innovative engagement with stakeholders. It is evident from our provisional model that numerous factors need to combine and interact to enable and sustain a successful frail older person\\'s pathway.

  6. What makes health demand-side financing schemes work in low- and middle-income countries? A realist review

    Directory of Open Access Journals (Sweden)

    Saji S. Gopalan

    2014-12-01

    Full Text Available This realist review explored causal pathways of the possible consumer effects of health sector demand-side financial (DSF incentives, their contextual factors and mechanisms in low-and-middle-income countries. We searched six electronic data bases and identified 659 abstracts with different evaluation designs. Based on methodological rigor and content relevance, only 24 studies published up to April 2013 were selected for the final review. A conceptual framework consisting of various program theories on potential context-mechanism-outcome (C-M-O configuration of DSF initiative was designed, tested and adapted during the review. Synthesized results were presented as a C-M-O configuration for each of the consumer-side effect. DSF was effective to improve health seeking behaviour considerably and health status to some extent. The causal pathway of DSF’s functioning and effectiveness was not linear. Key demand-side contextual factors which affected DSF’s consumer-side effects were background characteristics of the beneficiaries including their socio-cultural beliefs, motivations, and level of health awareness. At the supply-side, service availability status and provider incentives were contextual determinants. The mechanisms which enabled the interaction of contextual influence were consumer and provider accountability and consumer trust on providers. In order to enhance DSF programs’ effectiveness, their design and implementation should carefully consider the potential contextual elements that may influence the causal pathways.

  7. Realistic dust and water cycles in the MarsWRF GCM using coupled two-moment microphysics

    Science.gov (United States)

    Lee, Christopher; Richardson, Mark Ian; Mischna, Michael A.; Newman, Claire E.

    2017-10-01

    Dust and water ice aerosols significantly complicate the Martian climate system because the evolution of the two aerosol fields is coupled through microphysics and because both aerosols strongly interact with visible and thermal radiation. The combination of strong forcing feedback and coupling has led to various problems in understanding and modeling of the Martian climate: in reconciling cloud abundances at different locations in the atmosphere, in generating a stable dust cycle, and in preventing numerical instability within models.Using a new microphysics model inside the MarsWRF GCM we show that fully coupled simulations produce more realistic simulation of the Martian climate system compared to a dry, dust only simulations. In the coupled simulations, interannual variability and intra-annual variability are increased, strong 'solstitial pause' features are produced in both winter high latitude regions, and dust storm seasons are more varied, with early southern summer (Ls 180) dust storms and/or more than one storm occurring in some seasons.A new microphysics scheme was developed as a part of this work and has been included in the MarsWRF model. The scheme uses split spectral/spatial size distribution numerics with adaptive bin sizes to track particle size evolution. Significantly, this scheme is highly accurate, numerically stable, and is capable of running with time steps commensurate with those of the parent atmospheric model.

  8. Protocol--realist and meta-narrative evidence synthesis: evolving standards (RAMESES).

    Science.gov (United States)

    Greenhalgh, Trisha; Wong, Geoff; Westhorp, Gill; Pawson, Ray

    2011-08-16

    There is growing interest in theory-driven, qualitative and mixed-method approaches to systematic review as an alternative to (or to extend and supplement) conventional Cochrane-style reviews. These approaches offer the potential to expand the knowledge base in policy-relevant areas - for example by explaining the success, failure or mixed fortunes of complex interventions. However, the quality of such reviews can be difficult to assess. This study aims to produce methodological guidance, publication standards and training resources for those seeking to use the realist and/or meta-narrative approach to systematic review. We will: [a] collate and summarise existing literature on the principles of good practice in realist and meta-narrative systematic review; [b] consider the extent to which these principles have been followed by published and in-progress reviews, thereby identifying how rigour may be lost and how existing methods could be improved; [c] using an online Delphi method with an interdisciplinary panel of experts from academia and policy, produce a draft set of methodological steps and publication standards; [d] produce training materials with learning outcomes linked to these steps; [e] pilot these standards and training materials prospectively on real reviews-in-progress, capturing methodological and other challenges as they arise; [f] synthesise expert input, evidence review and real-time problem analysis into more definitive guidance and standards; [g] disseminate outputs to audiences in academia and policy. The outputs of the study will be threefold:1. Quality standards and methodological guidance for realist and meta-narrative reviews for use by researchers, research sponsors, students and supervisors2. A 'RAMESES' (Realist and Meta-review Evidence Synthesis: Evolving Standards) statement (comparable to CONSORT or PRISMA) of publication standards for such reviews, published in an open-access academic journal.3. A training module for researchers

  9. Protocol - realist and meta-narrative evidence synthesis: Evolving Standards (RAMESES

    Directory of Open Access Journals (Sweden)

    Westhorp Gill

    2011-08-01

    Full Text Available Abstract Background There is growing interest in theory-driven, qualitative and mixed-method approaches to systematic review as an alternative to (or to extend and supplement conventional Cochrane-style reviews. These approaches offer the potential to expand the knowledge base in policy-relevant areas - for example by explaining the success, failure or mixed fortunes of complex interventions. However, the quality of such reviews can be difficult to assess. This study aims to produce methodological guidance, publication standards and training resources for those seeking to use the realist and/or meta-narrative approach to systematic review. Methods/design We will: [a] collate and summarise existing literature on the principles of good practice in realist and meta-narrative systematic review; [b] consider the extent to which these principles have been followed by published and in-progress reviews, thereby identifying how rigour may be lost and how existing methods could be improved; [c] using an online Delphi method with an interdisciplinary panel of experts from academia and policy, produce a draft set of methodological steps and publication standards; [d] produce training materials with learning outcomes linked to these steps; [e] pilot these standards and training materials prospectively on real reviews-in-progress, capturing methodological and other challenges as they arise; [f] synthesise expert input, evidence review and real-time problem analysis into more definitive guidance and standards; [g] disseminate outputs to audiences in academia and policy. The outputs of the study will be threefold: 1. Quality standards and methodological guidance for realist and meta-narrative reviews for use by researchers, research sponsors, students and supervisors 2. A 'RAMESES' (Realist and Meta-review Evidence Synthesis: Evolving Standards statement (comparable to CONSORT or PRISMA of publication standards for such reviews, published in an open

  10. A realist review of interventions and strategies to promote evidence-informed healthcare: a focus on change agency.

    Science.gov (United States)

    McCormack, Brendan; Rycroft-Malone, Joanne; Decorby, Kara; Hutchinson, Alison M; Bucknall, Tracey; Kent, Bridie; Schultz, Alyce; Snelgrove-Clarke, Erna; Stetler, Cheyl; Titler, Marita; Wallin, Lars; Wilson, Valerie

    2013-09-08

    Change agency in its various forms is one intervention aimed at improving the effectiveness of the uptake of evidence. Facilitators, knowledge brokers and opinion leaders are examples of change agency strategies used to promote knowledge utilization. This review adopts a realist approach and addresses the following question: What change agency characteristics work, for whom do they work, in what circumstances and why? The literature reviewed spanned the period 1997-2007. Change agency was operationalized as roles that are aimed at effecting successful change in individuals and organizations. A theoretical framework, developed through stakeholder consultation formed the basis for a search for relevant literature. Team members, working in sub groups, independently themed the data and developed chains of inference to form a series of hypotheses regarding change agency and the role of change agency in knowledge use. 24, 478 electronic references were initially returned from search strategies. Preliminary screening of the article titles reduced the list of potentially relevant papers to 196. A review of full document versions of potentially relevant papers resulted in a final list of 52 papers. The findings add to the knowledge of change agency as they raise issues pertaining to how change agents' function, how individual change agent characteristics effect evidence-informed health care, the influence of interaction between the change agent and the setting and the overall effect of change agency on knowledge utilization. Particular issues are raised such as how accessibility of the change agent, their cultural compatibility and their attitude mediate overall effectiveness. Findings also indicate the importance of promoting reflection on practice and role modeling. The findings of this study are limited by the complexity and diversity of the change agency literature, poor indexing of literature and a lack of theory-driven approaches. This is the first realist review of

  11. Regional rigorous 3-D modelling of ground geoelectric field due to realistic geomagnetic disturbances. An approach and implementation.

    Science.gov (United States)

    Ivannikova, Elena; Kruglyakov, Mikhail; Kuvshinov, Alexey; Rastaetter, Lutz; Pulkkinen, Antti

    2017-04-01

    Strong eruptions at the Sun's surface produce large release of plasma, which with a high speed (solar wind) flows into space. Solar wind interaction with the Earth's magnetosphere and the ionosphere leads to a continuous disturbance of the geomagnetic field. This fluctuating geomagnetic field induces a ground geoelectric field that in turn generates geomagnetically induced currents (GICs) in technological systems, such as power grids and pipelines. It is well known that GICs are one of the most dangerous factors affecting the operation of the above systems. Thus, an accurate modelling of the spatio-temporal evolution of the geoelectric field during abnormal (storm-time) geomagnetic activity is a key consideration in estimating the hazard to technological systems from space weather. We present a numerical tool for regional modelling of the space weather influence on ground geoelectric field. The tool exploits realistic regional and global three-dimensional (3-D) models of Earth's electrical conductivity, and realistic global models of the spatio-temporal evolution of magnetospheric and ionospheric current systems responsible for geomagnetic disturbances. The tool involves four steps. First, we compute the spatio-temporal distribution of external magnetic field on a regular grid at the surface of the Earth using a magnetohydrodynamic model of the magnetosphere coupled to an electrostatic model of the ionosphere. Second, from the external magnetic field we compute the global source in the form of equivalent currents flowing in a thin shell above the Earth. Third, for a given global source and a given global 3-D conductivity model of the Earth we compute ground geoelectric field globally at a coarse grid (using spherical geometry). Finally, for a given source and a given regional 3-D conductivity model(s) of the Earth we compute geoelectric field regionally (using Cartesian geometry) at a dense grid utilizing the results from the global modelling. Both global and

  12. Understanding how self-management interventions work for disadvantaged populations living with chronic conditions: protocol for a realist synthesis.

    Science.gov (United States)

    Mills, Susan L; Pumarino, Javiera; Clark, Nancy; Carroll, Simon; Dennis, Sarah; Koehn, Sharon; Yu, Tricia; Davis, Connie; Fong, Maylene

    2014-07-01

    Self-management programmes are complex interventions aimed at improving the way individuals self-manage chronic conditions, but there are questions about the overall impact of these programmes on disadvantaged populations, in terms of their capacity to engage with and receive the benefits from these initiatives. Given the increased resources being directed towards self-management initiatives, clinicians and policy makers need knowledge on how self-management interventions work for these populations. Most systematic reviews of self-management interventions do not consider the complex interactions between implementation contexts, intervention strategies, and mechanisms that influence how self-management interventions work in real life for disadvantaged groups. To address the need for better understanding of these mechanisms and to create context-relevant knowledge, we are conducting a realist synthesis of evidence on self-management interventions for disadvantaged populations living with chronic conditions. The primary research question is: What are the key mechanisms operating in chronic condition self-management interventions among disadvantaged populations? In this protocol, we outline the steps we will take to identify the programme theory for self-management interventions and candidate middle-range theories; to search for evidence in academic and grey literature; to appraise and extract the collected evidence; to synthesise and interpret the findings to generate key context-mechanism-outcome configurations and to disseminate results to relevant stakeholder and to peer-review publications. Understandings of how chronic conditions self-management interventions work among disadvantaged populations is essential knowledge for clinicians and other decision makers who need to know which programmes they should implement for which groups. Results will also benefit medical researchers who want to direct effort towards current gaps in knowledge in order to advance the self

  13. Transition from children's to adult services for young adults with life-limiting conditions: A realist review of the literature.

    Science.gov (United States)

    Kerr, Helen; Price, Jayne; Nicholl, Honor; O'Halloran, Peter

    2017-11-01

    Improvements in care and treatment have led to more young adults with life-limiting conditions living beyond childhood, which means they must make the transition from children's to adult services. This has proved a challenging process for both young adults and service providers, with complex transition interventions interacting in unpredictable ways with local contexts. To explain how intervention processes interact with contextual factors to help transition from children's to adult services for young adults with life-limiting conditions. Systematic realist review of the literature. Literature was sourced from four electronic databases: Embase, MEDLINE, Science Direct and Cochrane Library from January 1995 to April 2016. This was supplemented with a search in Google Scholar and articles sourced from reference lists of included papers. Data were extracted using an adapted standardised data extraction tool which included identifying information related to interventions, mechanisms, contextual influences and outcomes. Two reviewers assessed the relevance of papers based on the inclusion criteria. Methodological rigor was assessed using the relevant Critical Appraisal Skills Programme tools. 78 articles were included in the review. Six interventions were identified related to an effective transition to adult services. Contextual factors include the need for children's service providers to collaborate with adult service providers to prepare an environment with knowledgeable staff and adequate resources. Mechanisms triggered by the interventions include a sense of empowerment and agency amongst all stakeholders. Early planning, collaboration between children's and adult service providers, and a focus on increasing the young adults' confidence in decision-making and engaging with adult services, are vital to a successful transition. Interventions should be tailored to their context and focused not only on organisational procedures but on equipping young adults, parents

  14. Saturating interactions in /sup 4/He with density dependence

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, S.D.; Resler, D.A.; Moszkowski, S.A.

    1989-05-03

    With the advent of larger and faster computers, as well as modern shell model codes, nuclear structure calculations for the light nuclei (A<16) which include full 2/bar h/..omega.. model spaces are quite feasible. However, there can be serious problems in the mixing of 2/bar h/..omega.. and higher excitations into the low-lying spectra if the effective interaction is non-saturating. Furthermore, effective interactions which are both saturating and density dependent have not generally been used in previous nuclear structure calculations. Therefore, we have undertaken studies of /sup 4/He using two-body potential interactions which incorporate both saturation and density-dependence. Encouraging initial results in remedying the mixing of 0 and 2/bar h/..omega.. excitations have been obtained. We have also considered the effects of our interaction on the /sup 4/He compressibility and the centroid of the breathing mode strength. First indications are that a saturating effective interaction, with a short-range density dependent part and a long-range density independent part, comes close to matching crude predictions for the compressibility of /sup 4/He. 11 refs., 6 tabs.

  15. Conditions for production of interdisciplinary teamwork outcomes in oncology teams: protocol for a realist evaluation.

    Science.gov (United States)

    Tremblay, Dominique; Touati, Nassera; Roberge, Danièle; Denis, Jean-Louis; Turcotte, Annie; Samson, Benoît

    2014-06-17

    Interdisciplinary teamwork (ITW) is designed to promote the active participation of several disciplines in delivering comprehensive cancer care to patients. ITW provides mechanisms to support continuous communication among care providers, optimize professionals' participation in clinical decision-making within and across disciplines, and foster care coordination along the cancer trajectory. However, ITW mechanisms are not activated optimally by all teams, resulting in a gap between desired outcomes of ITW and actual outcomes observed. The aim of the present study is to identify the conditions underlying outcome production by ITW in local oncology teams. This retrospective multiple case study will draw upon realist evaluation principles to explore associations among context, mechanisms and outcomes (CMO). The cases are nine interdisciplinary cancer teams that participated in a previous study evaluating ITW outcomes. Qualitative data sources will be used to construct a picture of CMO associations in each case. For data collection, reflexive focus groups will be held to capture patients' and professionals' perspectives on ITW, using the guiding question, 'What works, for whom, and under what circumstances?' Intra-case analysis will be used to trace associations between context, ITW mechanisms, and patient outcomes. Inter-case analysis will be used to compare the different cases' CMO associations for a better understanding of the phenomenon under study. This multiple case study will use realist evaluation principles to draw lessons about how certain contexts are more or less likely to produce particular outcomes. The results will make it possible to target more specifically the actions required to optimize structures and to activate the best mechanisms to meet the needs of cancer patients. This project could also contribute significantly to the development of improved research methods for conducting realist evaluations of complex healthcare interventions. To our

  16. A realist review of brief interventions for alcohol misuse delivered in emergency departments.

    Science.gov (United States)

    Davey, Caitlin J; Landy, Meredith S H; Pecora, Amanda; Quintero, David; McShane, Kelly E

    2015-04-09

    Brief interventions (BIs) involve screening for alcohol misuse and providing feedback to patients about their use, with the aim of reducing alcohol consumption and related consequences. BIs have been implemented in various healthcare settings, including emergency departments (ED), where they have been found to contribute mixed results in their ability to address alcohol misuse among adults. Mechanisms through which BIs work and contextual factors impacting BI effectiveness are not clear. The purpose of this review was to understand how, for whom, and under what circumstances BIs work for adults misusing alcohol and who have been admitted to an ED. A realist review was chosen to answer these questions as realist reviews create context-mechanism-outcome configurations, leading to the development of comprehensive and detailed theories; in this case explaining how and for whom BIs work. Databases including PsycINFO, Healthstar, CINAHL, Medline, and Nursing and Allied Health were searched for articles published until December 2013. The search strategy focused on studies examining BIs that targeted alcohol misuse among adults admitted into the ED. The search identified 145 relevant abstracts, of which 36 were included in the review. The literature was synthesized qualitatively (immersion/crystallization). Four mechanisms were found within reviewed studies, including engagement in/retention of BI materials, resolving ambivalence, increased awareness/insight into consequences of drinking, and increased self-efficacy/empowerment to use skills for change. The following contexts were found to impact mechanisms: emotional state, injury attributed to alcohol use, severity of alcohol use, and baseline stage of change. This realist review provides advances in theories regarding which mechanisms to target during a BI and which contexts create the most favorable conditions for these mechanisms to occur, ultimately leading to optimal BI outcomes. These results can inform future

  17. Parents' views of cancer-directed therapy for children with no realistic chance for cure.

    Science.gov (United States)

    Mack, Jennifer W; Joffe, Steven; Hilden, Joanne M; Watterson, Jan; Moore, Caron; Weeks, Jane C; Wolfe, Joanne

    2008-10-10

    Previous literature suggests that parents often wish to continue cancer-directed therapy for their children with incurable cancer. We assessed parents' experiences with treatment for their children with cancer and no realistic chance of cure. We administered questionnaires to 141 parents of children with cancer who died after receiving care at one of two cancer centers. Parents were asked whether the child benefited and suffered from treatment administered after the parent recognized that cure was not a realistic expectation, and whether they would recommend cancer-directed therapy to other families of children with advanced cancer. Fifty-three (38%) of 141 children received cancer-directed therapy after the parent recognized that the child had no realistic chance for cure. Most of these parents felt that their child had experienced at least some suffering resulting from the therapy (61%, 31 of 51) and little to no benefit (57%, 29 of 51). Fifty-one (38%) of 135 parents overall would recommend standard chemotherapy and 46 (33%) of 140 would recommend experimental chemotherapy to families of children with advanced cancer. Even parents who would not recommend standard chemotherapy generally felt the physician should offer it (91%, 88 of 97). Parents who reported that their children experienced suffering resulting from cancer-directed therapy (odds ratio = 0.46; P = .02) were less likely to recommend standard chemotherapy to other families. Although many parents choose treatment for their children with incurable cancer, bereaved parents often would not recommend such therapy. Parents who felt their children suffered as a result of cancer treatment were particularly unlikely to recommend it.

  18. Development Considerations of AREVA NP Inc.'s Realistic LBLOCA Analysis Methodology

    Directory of Open Access Journals (Sweden)

    Robert P. Martin

    2008-01-01

    Full Text Available The AREVA NP Inc. realistic large-break loss-of-coolant-accident (LOCA analysis methodology references the 1988 amended 10 CFR 50.46 allowing best-estimate calculations of emergency core cooling system performance. This methodology conforms to the code scaling, applicability, and uncertainty (CSAU methodology developed by the Technical Program Group for the United States Nuclear Regulatory Commission in the late 1980s. In addition, several practical considerations were revealed with the move to a production application. This paper describes the methodology development within the CSAU framework and utility objectives, lessons learned, and insight about current LOCA issues.

  19. Is China becoming more Aggressive? A Neo-classical Realist Analysis

    DEFF Research Database (Denmark)

    Sørensen, Camilla T. N.

    2013-01-01

    In this article I seek to improve the dominant neorealist analysis of China's rise. I offer a neoclassical realist analytical framework in order to identify the influence of certain Chinese domestic developments and priorities on Chinese foreign and security policy behavior. Rather than reflecting...... a more self-confident and aggressive China, developments in Chinese foreign and security policy in recent years reveal an internally conflicted, inward-looking, and reactive China not yet ready for its new international role. Beijing is uncertain how to manage the challenges and the inevitable tension...

  20. A virtual auditory environment for investigating the auditory signal processing of realistic sounds

    DEFF Research Database (Denmark)

    Favrot, Sylvain Emmanuel

    A loudspeaker-based virtual auditory environment (VAE) has been developed to provide a realistic versatile research environment for investigating the auditory signal processing in real environments, i.e., considering multiple sound sources and room reverberation. The VAE allows a full control...... of the acoustic scenario in order to systematically study the auditory processing of reverberant sounds. It is based on the ODEON software, which is state-of-the-art software for room acoustic simulations developed at Acoustic Technology, DTU. First, a MATLAB interface to the ODEON software has been developed...