WorldWideScience

Sample records for exponential family observations

  1. Limit laws for exponential families

    OpenAIRE

    Balkema, August A.; Klüppelberg, Claudia; Resnick, Sidney I.

    1999-01-01

    For a real random variable [math] with distribution function [math] , define ¶ [math] ¶ The distribution [math] generates a natural exponential family of distribution functions [math] , where ¶ [math] ¶ We study the asymptotic behaviour of the distribution functions [math] as [math] increases to [math] . If [math] then [math] pointwise on [math] . It may still be possible to obtain a non-degenerate weak limit law [math] by choosing suitable scaling and centring constants [math] an...

  2. Statistical estimation for truncated exponential families

    CERN Document Server

    Akahira, Masafumi

    2017-01-01

    This book presents new findings on nonregular statistical estimation. Unlike other books on this topic, its major emphasis is on helping readers understand the meaning and implications of both regularity and irregularity through a certain family of distributions. In particular, it focuses on a truncated exponential family of distributions with a natural parameter and truncation parameter as a typical nonregular family. This focus includes the (truncated) Pareto distribution, which is widely used in various fields such as finance, physics, hydrology, geology, astronomy, and other disciplines. The family is essential in that it links both regular and nonregular distributions, as it becomes a regular exponential family if the truncation parameter is known. The emphasis is on presenting new results on the maximum likelihood estimation of a natural parameter or truncation parameter if one of them is a nuisance parameter. In order to obtain more information on the truncation, the Bayesian approach is also considere...

  3. Exponential Boundary Observers for Pressurized Water Pipe

    Science.gov (United States)

    Hermine Som, Idellette Judith; Cocquempot, Vincent; Aitouche, Abdel

    2015-11-01

    This paper deals with state estimation on a pressurized water pipe modeled by nonlinear coupled distributed hyperbolic equations for non-conservative laws with three known boundary measures. Our objective is to estimate the fourth boundary variable, which will be useful for leakage detection. Two approaches are studied. Firstly, the distributed hyperbolic equations are discretized through a finite-difference scheme. By using the Lipschitz property of the nonlinear term and a Lyapunov function, the exponential stability of the estimation error is proven by solving Linear Matrix Inequalities (LMIs). Secondly, the distributed hyperbolic system is preserved for state estimation. After state transformations, a Luenberger-like PDE boundary observer based on backstepping mathematical tools is proposed. An exponential Lyapunov function is used to prove the stability of the resulted estimation error. The performance of the two observers are shown on a water pipe prototype simulated example.

  4. On weak exponential expansiveness of evolution families in Banach spaces.

    Science.gov (United States)

    Yue, Tian; Song, Xiao-qiu; Li, Dong-qing

    2013-01-01

    The aim of this paper is to give several characterizations for the property of weak exponential expansiveness for evolution families in Banach spaces. Variants for weak exponential expansiveness of some well-known results in stability theory (Datko (1973), Rolewicz (1986), Ichikawa (1984), and Megan et al. (2003)) are obtained.

  5. The q-exponential family in statistical physics

    International Nuclear Information System (INIS)

    Naudts, Jan

    2010-01-01

    The Boltzmann-Gibbs probability distribution, seen as a statistical model, belongs to the exponential family. Recently, the latter concept has been generalized. The q-exponential family has been shown to be relevant for the statistical description of small isolated systems. Two main applications are reviewed: 1. The distribution of the momentum of a single particle is a q-Gaussian, the distribution of its velocity is a deformed Maxwellian; 2. The configurational density distribution belongs to the q-exponential family. The definition of the temperature of small isolated systems is discussed. It depends on defining the thermodynamic entropy of a microcanonical ensemble in a suitable manner. The simple example of non-interacting harmonic oscillators shows that Renyi's entropy functional leads to acceptable results.

  6. Characterizing quantum correlations. Entanglement, uncertainty relations and exponential families

    International Nuclear Information System (INIS)

    Niekamp, Soenke

    2012-01-01

    This thesis is concerned with different characterizations of multi-particle quantum correlations and with entropic uncertainty relations. The effect of statistical errors on the detection of entanglement is investigated. First, general results on the statistical significance of entanglement witnesses are obtained. Then, using an error model for experiments with polarization-entangled photons, it is demonstrated that Bell inequalities with lower violation can have higher significance. The question for the best observables to discriminate between a state and the equivalence class of another state is addressed. Two measures for the discrimination strength of an observable are defined, and optimal families of observables are constructed for several examples. A property of stabilizer bases is shown which is a natural generalization of mutual unbiasedness. For sets of several dichotomic, pairwise anticommuting observables, uncertainty relations using different entropies are constructed in a systematic way. Exponential families provide a classification of states according to their correlations. In this classification scheme, a state is considered as k-correlated if it can be written as thermal state of a k-body Hamiltonian. Witness operators for the detection of higher-order interactions are constructed, and an algorithm for the computation of the nearest k-correlated state is developed.

  7. Characterizing quantum correlations. Entanglement, uncertainty relations and exponential families

    Energy Technology Data Exchange (ETDEWEB)

    Niekamp, Soenke

    2012-04-20

    This thesis is concerned with different characterizations of multi-particle quantum correlations and with entropic uncertainty relations. The effect of statistical errors on the detection of entanglement is investigated. First, general results on the statistical significance of entanglement witnesses are obtained. Then, using an error model for experiments with polarization-entangled photons, it is demonstrated that Bell inequalities with lower violation can have higher significance. The question for the best observables to discriminate between a state and the equivalence class of another state is addressed. Two measures for the discrimination strength of an observable are defined, and optimal families of observables are constructed for several examples. A property of stabilizer bases is shown which is a natural generalization of mutual unbiasedness. For sets of several dichotomic, pairwise anticommuting observables, uncertainty relations using different entropies are constructed in a systematic way. Exponential families provide a classification of states according to their correlations. In this classification scheme, a state is considered as k-correlated if it can be written as thermal state of a k-body Hamiltonian. Witness operators for the detection of higher-order interactions are constructed, and an algorithm for the computation of the nearest k-correlated state is developed.

  8. Geometry of q-Exponential Family of Probability Distributions

    Directory of Open Access Journals (Sweden)

    Shun-ichi Amari

    2011-06-01

    Full Text Available The Gibbs distribution of statistical physics is an exponential family of probability distributions, which has a mathematical basis of duality in the form of the Legendre transformation. Recent studies of complex systems have found lots of distributions obeying the power law rather than the standard Gibbs type distributions. The Tsallis q-entropy is a typical example capturing such phenomena. We treat the q-Gibbs distribution or the q-exponential family by generalizing the exponential function to the q-family of power functions, which is useful for studying various complex or non-standard physical phenomena. We give a new mathematical structure to the q-exponential family different from those previously given. It has a dually flat geometrical structure derived from the Legendre transformation and the conformal geometry is useful for understanding it. The q-version of the maximum entropy theorem is naturally induced from the q-Pythagorean theorem. We also show that the maximizer of the q-escort distribution is a Bayesian MAP (Maximum A posteriori Probability estimator.

  9. An exponential observer for the generalized Rossler chaotic system

    International Nuclear Information System (INIS)

    Sun, Y.-J.

    2009-01-01

    In this paper, the generalized Rossler chaotic system is considered and the state observation problem of such a system is investigated. Based on the time-domain approach, a state observer for the generalized Rossler chaotic system is developed to guarantee the global exponential stability of the resulting error system. Moreover, the guaranteed exponential convergence rate can be arbitrarily pre-specified. Finally, a numerical example is provided to illustrate the feasibility and effectiveness of the obtained result.

  10. On limiting towards the boundaries of exponential families

    Czech Academy of Sciences Publication Activity Database

    Matúš, František

    2015-01-01

    Roč. 51, č. 5 (2015), s. 725-738 ISSN 0023-5954 R&D Projects: GA ČR GA13-20012S Institutional support: RVO:67985556 Keywords : exponential family * variance function * Kullback--Leibler divergence * relative entropy * information divergence * mean parametrization * convex support Subject RIV: BD - Theory of Information Impact factor: 0.628, year: 2015 http://library.utia.cas.cz/separaty/2016/MTR/matus-0455604.pdf

  11. Exponential Family Techniques for the Lognormal Left Tail

    DEFF Research Database (Denmark)

    Asmussen, Søren; Jensen, Jens Ledet; Rojas-Nandayapa, Leonardo

    Let X be lognormal(μ,σ2) with density f(x), let θ>0 and define L(θ)=Ee−θX. We study properties of the exponentially tilted density (Esscher transform) fθ(x)=e−θxf(x)/L(θ), in particular its moments, its asymptotic form as θ→∞ and asymptotics for the saddlepoint θ(x) determined by E[Xe−θX]/L(θ)=x....... demonstrate logarithmic efficiency. Numerical examples for the cdf Fn(x) and the pdf fn(x) of Sn are given in a range of values of σ2,n,x motivated from portfolio Value-at-Risk calculations....

  12. A closed-form expression for the Sharma–Mittal entropy of exponential families

    International Nuclear Information System (INIS)

    Nielsen, Frank; Nock, Richard

    2012-01-01

    The Sharma–Mittal entropies generalize the celebrated Shannon, Rényi and Tsallis entropies. We report a closed-form formula for the Sharma–Mittal entropies and relative entropies for arbitrary exponential family distributions. We explicitly instantiate the formula for the case of the multivariate Gaussian distributions and discuss its estimation. (fast track communication)

  13. Form factors of exponential fields for two-parametric family of integrable models

    International Nuclear Information System (INIS)

    Fateev, V.A.; Lashkevich, M.

    2004-01-01

    A two-parametric family of integrable models (the SS model) that contains as particular cases several well known integrable quantum field theories is considered. After the quantum group restriction it describes a wide class of integrable perturbed conformal field theories. Exponential fields in the SS model are closely related to the primary fields in these perturbed theories. We use the bosonization approach to derive an integral representation for the form factors of the exponential fields in the SS model. The same representations for the sausage model and the cosine-cosine model are obtained as limiting cases. The results are tested at the special points, where the theory contains free particles

  14. Form factors of exponential fields for two-parametric family of integrable models

    Science.gov (United States)

    Fateev, V. A.; Lashkevich, M.

    2004-09-01

    A two-parametric family of integrable models (the SS model) that contains as particular cases several well known integrable quantum field theories is considered. After the quantum group restriction it describes a wide class of integrable perturbed conformal field theories. Exponential fields in the SS model are closely related to the primary fields in these perturbed theories. We use the bosonization approach to derive an integral representation for the form factors of the exponential fields in the SS model. The same representations for the sausage model and the cosine-cosine model are obtained as limiting cases. The results are tested at the special points, where the theory contains free particles.

  15. A simple derivation of r* for curved exponential families

    DEFF Research Database (Denmark)

    Jensen, Jens Ledet

    1997-01-01

    For curved exponential families we consider modified likelihood ratio statistics of the form rL = r + log (u/r)/r, where r is the signed root of the likelihood ratio statistic. We are testing a one-dimensional hypothesis, but in order to specify approximate ancillary statistics we consider the test...... approximation followed by a transformation. We give explicit formulas for the statistic u, and include a discussion of the case where some coordinates of the underlying variable are lattice....

  16. Optimality conditions for maximizers of the information divergence from an exponential family

    Czech Academy of Sciences Publication Activity Database

    Matúš, František

    2007-01-01

    Roč. 43, č. 5 (2007), s. 731-746 ISSN 0023-5954 R&D Projects: GA AV ČR IAA100750603 Institutional research plan: CEZ:AV0Z10750506 Keywords : Kullback-Leibler divergence * relative entropy * exponential family * information projection * log-Laplace transform * cumulant generating function * directional derivatives * convex function s * first order optimality conditions * polytopes Subject RIV: BA - General Mathematics Impact factor: 0.552, year: 2007

  17. Sequential estimation and diffusion of information over networks: A Bayesian approach with exponential family of distributions

    Czech Academy of Sciences Publication Activity Database

    Dedecius, Kamil; Djurić, P. M.

    2017-01-01

    Roč. 65, č. 7 (2017), s. 1795-1809 ISSN 1053-587X R&D Projects: GA ČR(CZ) GP14-06678P Institutional support: RVO:67985556 Keywords : diffusion network * diffusion estimation * adaptation * combination * exponential family Subject RIV: BD - Theory of Information OBOR OECD: Applied mathematics Impact factor: 4.300, year: 2016 http://library.utia.cas.cz/separaty/2016/AS/dedecius-0467560.pdf

  18. Turning Simulation into Estimation: Generalized Exchange Algorithms for Exponential Family Models.

    Directory of Open Access Journals (Sweden)

    Maarten Marsman

    Full Text Available The Single Variable Exchange algorithm is based on a simple idea; any model that can be simulated can be estimated by producing draws from the posterior distribution. We build on this simple idea by framing the Exchange algorithm as a mixture of Metropolis transition kernels and propose strategies that automatically select the more efficient transition kernels. In this manner we achieve significant improvements in convergence rate and autocorrelation of the Markov chain without relying on more than being able to simulate from the model. Our focus will be on statistical models in the Exponential Family and use two simple models from educational measurement to illustrate the contribution.

  19. Exponential Stability of the Monotubular Heat Exchanger Equation with Time Delay in Boundary Observation

    Directory of Open Access Journals (Sweden)

    Xue-Lian Jin

    2017-01-01

    Full Text Available The exponential stability of the monotubular heat exchanger equation with boundary observation possessing a time delay and inner control was investigated. Firstly, the close-loop system was translated into an abstract Cauchy problem in the suitable state space. A uniformly bounded C0-semigroup generated by the close-loop system, which implies that the unique solution of the system exists, was shown. Secondly, the spectrum configuration of the closed-loop system was analyzed and the eventual differentiability and the eventual compactness of the semigroup were shown by the resolvent estimates on some resolvent sets. This implies that the spectrum-determined growth assumption holds. Finally, a sufficient condition, which is related to the physical parameters in the system and is independent of the time delay, of the exponential stability of the closed-loop system was given.

  20. A Novel Simulation Method for Binary Discrete Exponential Families, with Application to Social Networks.

    Science.gov (United States)

    Butts, Carter T

    Stochastic models for finite binary vectors are widely used in sociology, with examples ranging from social influence models on dichotomous behaviors or attitudes to models for random graphs. Exact sampling for such models is difficult in the presence of dependence, leading to the use of Markov chain Monte Carlo (MCMC) as an approximation technique. While often effective, MCMC methods have variable execution time, and the quality of the resulting draws can be difficult to assess. Here, we present a novel alternative method for approximate sampling from binary discrete exponential families having fixed execution time and well-defined quality guarantees. We demonstrate the use of this sampling procedure in the context of random graph generation, with an application to the simulation of a large-scale social network using both geographical covariates and dyadic dependence mechanisms.

  1. The discrete Laplace exponential family and estimation of Y-STR haplotype frequencies

    DEFF Research Database (Denmark)

    Andersen, Mikkel Meyer; Eriksen, Poul Svante; Morling, Niels

    2013-01-01

    of the Fisher-Wright model of evolution for haploid lineage DNA markers. An exponential family (a class of probability distributions that is well understood in probability theory such that inference is easily made by using existing software) called the 'discrete Laplace distribution' is described. We illustrate...... how well the discrete Laplace distribution approximates a more complicated distribution that arises by investigating the well-known population genetic Fisher-Wright model of evolution by a single-step mutation process. It was shown how the discrete Laplace distribution can be used to estimate...... haplotype frequencies for haploid lineage DNA markers (such as Y-chromosomal short tandem repeats), which in turn can be used to assess the evidential weight of a DNA profile found at a crime scene. This was done by making inference in a mixture of multivariate, marginally independent, discrete Laplace...

  2. Exponentiated Weibull distribution family under aperture averaging for Gaussian beam waves.

    Science.gov (United States)

    Barrios, Ricardo; Dios, Federico

    2012-06-04

    Nowadays, the search for a distribution capable of modeling the probability density function (PDF) of irradiance data under all conditions of atmospheric turbulence in the presence of aperture averaging still continues. Here, a family of PDFs alternative to the widely accepted Log-Normal and Gamma-Gamma distributions is proposed to model the PDF of the received optical power in free-space optical communications, namely, the Weibull and the exponentiated Weibull (EW) distribution. Particularly, it is shown how the proposed EW distribution offers an excellent fit to simulation and experimental data under all aperture averaging conditions, under weak and moderate turbulence conditions, as well as for point-like apertures. Another very attractive property of these distributions is the simple closed form expression of their respective PDF and cumulative distribution function.

  3. MAD Bayes for Tumor Heterogeneity - Feature Allocation with Exponential Family Sampling.

    Science.gov (United States)

    Xu, Yanxun; Müller, Peter; Yuan, Yuan; Gulukota, Kamalakar; Ji, Yuan

    2015-03-01

    We propose small-variance asymptotic approximations for inference on tumor heterogeneity (TH) using next-generation sequencing data. Understanding TH is an important and open research problem in biology. The lack of appropriate statistical inference is a critical gap in existing methods that the proposed approach aims to fill. We build on a hierarchical model with an exponential family likelihood and a feature allocation prior. The proposed implementation of posterior inference generalizes similar small-variance approximations proposed by Kulis and Jordan (2012) and Broderick et.al (2012b) for inference with Dirichlet process mixture and Indian buffet process prior models under normal sampling. We show that the new algorithm can successfully recover latent structures of different haplotypes and subclones and is magnitudes faster than available Markov chain Monte Carlo samplers. The latter are practically infeasible for high-dimensional genomics data. The proposed approach is scalable, easy to implement and benefits from the exibility of Bayesian nonparametric models. More importantly, it provides a useful tool for applied scientists to estimate cell subtypes in tumor samples. R code is available on http://www.ma.utexas.edu/users/yxu/.

  4. On transverse exponential stability and its use in incremental stability, observer and synchronization

    NARCIS (Netherlands)

    Andrieu, Vincent; Jayawardhana, Bayu; Praly, Laurent

    2013-01-01

    We study the relation between the exponential stability of an invariant manifold and the existence of a Riemannian metric for which the flow is “transversally” contracting. More precisely, we investigate how the following properties are related to each other: i). A manifold is “transversally”

  5. Closures of exponential families

    Czech Academy of Sciences Publication Activity Database

    Csiszár, I.; Matúš, František

    2005-01-01

    Roč. 33, č. 2 (2005), s. 582-600 ISSN 0091-1798 R&D Projects: GA AV ČR IAA1075104 Institutional research plan: CEZ:AV0Z10750506 Keywords : accessible face * convex core * information divergence Subject RIV: BA - General Mathematics Impact factor: 1.132, year: 2005

  6. Network clustering analysis using mixture exponential-family random graph models and its application in genetic interaction data.

    Science.gov (United States)

    Wang, Yishu; Zhao, Hongyu; Deng, Minghua; Fang, Huaying; Yang, Dejie

    2017-08-24

    Epistatic miniarrary profile (EMAP) studies have enabled the mapping of large-scale genetic interaction networks and generated large amounts of data in model organisms. It provides an incredible set of molecular tools and advanced technologies that should be efficiently understanding the relationship between the genotypes and phenotypes of individuals. However, the network information gained from EMAP cannot be fully exploited using the traditional statistical network models. Because the genetic network is always heterogeneous, for example, the network structure features for one subset of nodes are different from those of the left nodes. Exponentialfamily random graph models (ERGMs) are a family of statistical models, which provide a principled and flexible way to describe the structural features (e.g. the density, centrality and assortativity) of an observed network. However, the single ERGM is not enough to capture this heterogeneity of networks. In this paper, we consider a mixture ERGM (MixtureEGRM) networks, which model a network with several communities, where each community is described by a single EGRM.

  7. Deviations from exponential decay

    Science.gov (United States)

    Petridis, Athanasios; Staunton, Lawrence; Luban, Marshall; Vermedahl, Jon

    2003-10-01

    We study deviations from exponetial decay in cases when the initial wavefunction is set in a potential well and is not an eigenstate of this potential. We numerically solve the time-dependent Schroedinger equation and observe a decaying but oscillatory behavior of the survival probability. Analytical calculations have been performed proving that even in the case of a simple finite square-well potential deviations from exponential decay persist for large times. Possible explanations for the limiting exponential decay for many-particle systems are developed.

  8. Estimating exponential scheduling preferences

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Börjesson, Maria; Engelson, Leonid

    behaviour, based on a theoretical model that has an exponential-exponential specification of H and W and so is more general than the models with the additivity property. We adapt the model to take into account that the marginal utilities of travelling by car and public transport may be different...... drivers commuting to work in the morning in central Stockholm. The survey contains observations of choices between car and public transport travel alternatives, which differ in terms of departure time, monetary cost, and the distribution of travel time. We develop a discrete choice model to describe......Extended abstract Choice of departure time is a travel choice dimension that transportation planners often need to forecast in appraisal. A traveller may shift departure time in response to changes in expected travel time or travel time variability (TTV) or in response to time...

  9. An exponential distribution

    International Nuclear Information System (INIS)

    Anon

    2009-01-01

    In this presentation author deals with the probabilistic evaluation of product life on the example of the exponential distribution. The exponential distribution is special one-parametric case of the weibull distribution.

  10. Partial Generalized Probability Weighted Moments for Exponentiated Exponential Distribution

    Directory of Open Access Journals (Sweden)

    Neema Mohamed El Haroun

    2015-09-01

    Full Text Available The generalized probability weighted moments are widely used in hydrology for estimating parameters of flood distributions from complete sample. The method of partial generalized probability weighted moments was used to estimate the parameters of distributions from censored sample. This article offers new method called partial generalized probability weighted moments (PGPWMs for the analysis of censored data. The method of PGPWMs is an extended class from partial generalized probability weighted moments. To illustrate the new method, estimation of the unknown parameters from exponentiated exponential distribution based on doubly censored sample is considered. PGPWMs estimators for right and left censored samples are obtained as special cases.   Simulation study is conducted to investigate performance of estimates for exponentiated exponential distribution. Comparison between estimators is made through simulation via their biases and  mean square errors. An illustration with real data is provided. Normal 0 false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"جدول عادي"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;}

  11. Extended Poisson Exponential Distribution

    Directory of Open Access Journals (Sweden)

    Anum Fatima

    2015-09-01

    Full Text Available A new mixture of Modified Exponential (ME and Poisson distribution has been introduced in this paper. Taking the Maximum of Modified Exponential random variable when the sample size follows a zero truncated Poisson distribution we have derived the new distribution, named as Extended Poisson Exponential distribution. This distribution possesses increasing and decreasing failure rates. The Poisson-Exponential, Modified Exponential and Exponential distributions are special cases of this distribution. We have also investigated some mathematical properties of the distribution along with Information entropies and Order statistics of the distribution. The estimation of parameters has been obtained using the Maximum Likelihood Estimation procedure. Finally we have illustrated a real data application of our distribution.

  12. Stretched-to-compressed-exponential crossover observed in the electrical degradation kinetics of some spinel-metallic screen-printed structures

    Science.gov (United States)

    Balitska, V.; Shpotyuk, O.; Brunner, M.; Hadzaman, I.

    2018-02-01

    Thermally-induced (170 °C) degradation-relaxation kinetics is examined in screen-printed structures composed of spinel Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics with conductive Ag or Ag-Pd layered electrodes. Structural inhomogeneities due to Ag and Ag-Pd diffusants in spinel phase environment play a decisive role in non-exponential kinetics of negative relative resistance drift. If Ag migration in spinel is inhibited by Pd addition due to Ag-Pd alloy, the kinetics attains stretched exponential behavior with ∼0.58 exponent, typical for one-stage diffusion in structurally-dispersive media. Under deep Ag penetration into spinel ceramics, as for thick films with Ag-layered electrodes, the degradation kinetics drastically changes, attaining features of two-step diffusing process governed by compressed-exponential dependence with power index of ∼1.68. Crossover from stretched- to compressed-exponential kinetics in spinel-metallic structures is mapped on free energy landscape of non-barrier multi-well system under strong perturbation from equilibrium, showing transition with a character downhill scenario resulting in faster than exponential decaying.

  13. Universality in stochastic exponential growth.

    Science.gov (United States)

    Iyer-Biswas, Srividya; Crooks, Gavin E; Scherer, Norbert F; Dinner, Aaron R

    2014-07-11

    Recent imaging data for single bacterial cells reveal that their mean sizes grow exponentially in time and that their size distributions collapse to a single curve when rescaled by their means. An analogous result holds for the division-time distributions. A model is needed to delineate the minimal requirements for these scaling behaviors. We formulate a microscopic theory of stochastic exponential growth as a Master Equation that accounts for these observations, in contrast to existing quantitative models of stochastic exponential growth (e.g., the Black-Scholes equation or geometric Brownian motion). Our model, the stochastic Hinshelwood cycle (SHC), is an autocatalytic reaction cycle in which each molecular species catalyzes the production of the next. By finding exact analytical solutions to the SHC and the corresponding first passage time problem, we uncover universal signatures of fluctuations in exponential growth and division. The model makes minimal assumptions, and we describe how more complex reaction networks can reduce to such a cycle. We thus expect similar scalings to be discovered in stochastic processes resulting in exponential growth that appear in diverse contexts such as cosmology, finance, technology, and population growth.

  14. The First Derivative of an Exponential Function with the "White Box/Black Box" Didactical Principle and Observations with GeoGebra

    Science.gov (United States)

    Budinski, Natalija; Subramaniam, Stephanie

    2013-01-01

    This paper shows how GeoGebra--a dynamic mathematics software--can be used to experiment, visualize and connect various concepts such as function, first derivative, slope, and tangent line. Students were given an assignment to determine the first derivative of the exponential function that they solved while experimenting with GeoGebra. GeoGebra…

  15. Phenomenology of stochastic exponential growth

    Science.gov (United States)

    Pirjol, Dan; Jafarpour, Farshid; Iyer-Biswas, Srividya

    2017-06-01

    Stochastic exponential growth is observed in a variety of contexts, including molecular autocatalysis, nuclear fission, population growth, inflation of the universe, viral social media posts, and financial markets. Yet literature on modeling the phenomenology of these stochastic dynamics has predominantly focused on one model, geometric Brownian motion (GBM), which can be described as the solution of a Langevin equation with linear drift and linear multiplicative noise. Using recent experimental results on stochastic exponential growth of individual bacterial cell sizes, we motivate the need for a more general class of phenomenological models of stochastic exponential growth, which are consistent with the observation that the mean-rescaled distributions are approximately stationary at long times. We show that this behavior is not consistent with GBM, instead it is consistent with power-law multiplicative noise with positive fractional powers. Therefore, we consider this general class of phenomenological models for stochastic exponential growth, provide analytical solutions, and identify the important dimensionless combination of model parameters, which determines the shape of the mean-rescaled distribution. We also provide a prescription for robustly inferring model parameters from experimentally observed stochastic growth trajectories.

  16. An Unusual Exponential Graph

    Science.gov (United States)

    Syed, M. Qasim; Lovatt, Ian

    2014-01-01

    This paper is an addition to the series of papers on the exponential function begun by Albert Bartlett. In particular, we ask how the graph of the exponential function y = e[superscript -t/t] would appear if y were plotted versus ln t rather than the normal practice of plotting ln y versus t. In answering this question, we find a new way to…

  17. Exponential and Logarithmic Functions

    OpenAIRE

    Todorova, Tamara

    2010-01-01

    Exponential functions find applications in economics in relation to growth and economic dynamics. In these fields, quite often the choice variable is time and economists are trying to determine the best timing for certain economic activities to take place. An exponential function is one in which the independent variable appears in the exponent. Very often that exponent is time. In highly mathematical courses, it is a truism that students learn by doing, not by reading. Tamara Todorova’s Pr...

  18. Top-down NOX emissions over European cities from LOTOS-EUROS simulated and OMI observed tropospheric NO2 columns using the Exponentially Modified Gaussian approach

    Science.gov (United States)

    Verstraeten, Willem W.; Folkert Boersma, K.; Douros, John; Williams, Jason E.; Eskes, Henk H.; Delcloo, Andy

    2017-04-01

    High nitrogen oxides concentrations at the surface (NOX = NO + NO2) impact humans and ecosystem badly and play a key role in tropospheric chemistry. Surface NOX emissions drive major processes in regional and global chemistry transport models (CTM). NOX contributes to the formation of acid rain, act as aerosol precursors and is an important trace gas for the formation of tropospheric ozone (O3). Via tropospheric O3, NOX indirectly affects the production of the hydroxyl radical which controls the chemical lifetime of key atmospheric pollutants and reactive greenhouse gases. High NOX emissions are mainly observed in polluted regions produced by anthropogenic combustion from industrial, traffic and household activities typically observed in large and densely populated urban areas. Accurate NOX inventories are essential, but state-of the- art emission databases may vary substantially and uncertainties are high since reported emissions factors may differ in order of magnitude and more. To date, the modelled NO2 concentrations and lifetimes have large associated uncertainties due to the highly non-linear small-scale chemistry that occurs in urban areas and uncertainties in the reaction rate data, missing nitrogen (N) species and volatile organic compounds (VOC) emissions, and incomplete knowledge of nitrogen oxides chemistry. Any overestimation in the chemical lifetime may mask missing NOX chemistry in current CTM's. By simultaneously estimating both the NO2 lifetime and concentrations, for instance by using the Exponentially Modified Gaussian (EMG), a better surface NOX emission flux estimate can be obtained. Here we evaluate if the EMG methodology can reproduce the emissions input from the tropospheric NO2 columns simulated by the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) CTM model. We apply the EMG methodology on LOTOS-EUROS simulated tropospheric NO2 columns for the period April-September 2013 for 21 selected European urban areas under windy

  19. Maximum likelihood estimation of exponential distribution under ...

    African Journals Online (AJOL)

    Maximum likelihood estimation of exponential distribution under type-ii censoring from imprecise data. ... Journal of Fundamental and Applied Sciences ... This paper deals with the estimation of exponential mean parameter under Type-II censoring scheme when the lifetime observations are fuzzy and are assumed to be ...

  20. Possible implications of exponential decay

    International Nuclear Information System (INIS)

    Steyerl, A.; Malik, S.S.

    1992-01-01

    Semiclassical concepts are developed which could make the appearance of a logarithmic nonlinearity in a Schroedinger-type equation plausible. This approach is based on the introduction of a novel wave function describing the center of mass (CM) motion of unstable particles or composite systems subject to statistical changes of their internal quantum state. The element of statistical randomness associated with a purely exponential decay law suggests the use of thermodynamic concepts like entropy and free energy. These concepts are applied only to a domain open-quotes blurredclose quotes by the quantum uncertainty principle where the problematic definition of a time and entropy operator might be possible. The paper consists of three main parts. Section 1 develops an extended nonrelativistic equation of motion. The proposed equation contains yet reinterprets the BBM equation, and for stable systems is reduced to the Schroedinger equation. Definite predictions are made for observable quantities. In Section 2, the family of localized, nonspreading ground-state solutions to the BBM equation is extended, in two and three spatial dimensions, to states classified by finite quantized angular momenta and definite values of entropy. The statistical behavior of CM systems and their electromagnetic interaction are investigated. In Section 3, implications of these concepts are outlined with emphasis on possible experimental manifestations. Suggested laboratory tests include high-precision measurements of unstable particle diffraction on linear gratings as well as neutron interferometer experiments of the type previously attempted to test the BBM equation. A further testing possibility is the investigation of particle resonances. An important feature of the present model is a subtle combination of quantum and classical aspects, achieved without compromising fundamental principles, while reinterpreting microreversibility. 46 refs., 6 figs., 4 tabs

  1. Continuous multivariate exponential extension

    International Nuclear Information System (INIS)

    Block, H.W.

    1975-01-01

    The Freund-Weinman multivariate exponential extension is generalized to the case of nonidentically distributed marginal distributions. A fatal shock model is given for the resulting distribution. Results in the bivariate case and the concept of constant multivariate hazard rate lead to a continuous distribution related to the multivariate exponential distribution (MVE) of Marshall and Olkin. This distribution is shown to be a special case of the extended Freund-Weinman distribution. A generalization of the bivariate model of Proschan and Sullo leads to a distribution which contains both the extended Freund-Weinman distribution and the MVE

  2. Estimating exponential scheduling preferences

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Börjesson, Maria; Engelson, Leonid

    2015-01-01

    distributed independent random variables: Assuming smooth preferences; this holds only for specifications with a constant marginal utility of time at the origin and an exponential or affine marginal utility of time at the destination. We apply a generalized version of this model to stated preference data...... utility of being at the origin. Another issue is that models with the exponential marginal utility formulation suffer from empirical identification problems. Though our results are not decisive, they partly support the constant-affine specification, in which the value of travel time variability...

  3. Comparing exponential and exponentiated models of drug demand in cocaine users.

    Science.gov (United States)

    Strickland, Justin C; Lile, Joshua A; Rush, Craig R; Stoops, William W

    2016-12-01

    Drug purchase tasks provide rapid and efficient measurement of drug demand. Zero values (i.e., prices with zero consumption) present a quantitative challenge when using exponential demand models that exponentiated models may resolve. We aimed to replicate and advance the utility of using an exponentiated model by demonstrating construct validity (i.e., association with real-world drug use) and generalizability across drug commodities. Participants (N = 40 cocaine-using adults) completed Cocaine, Alcohol, and Cigarette Purchase Tasks evaluating hypothetical consumption across changes in price. Exponentiated and exponential models were fit to these data using different treatments of zero consumption values, including retaining zeros or replacing them with 0.1, 0.01, or 0.001. Excellent model fits were observed with the exponentiated model. Means and precision fluctuated with different replacement values when using the exponential model but were consistent for the exponentiated model. The exponentiated model provided the strongest correlation between derived demand intensity (Q0) and self-reported free consumption in all instances (Cocaine r = .88; Alcohol r = .97; Cigarette r = .91). Cocaine demand elasticity was positively correlated with alcohol and cigarette elasticity. Exponentiated parameters were associated with real-world drug use (e.g., weekly cocaine use) whereas these correlations were less consistent for exponential parameters. Our findings show that selection of zero replacement values affects demand parameters and their association with drug-use outcomes when using the exponential model but not the exponentiated model. This work supports the adoption of the exponentiated demand model by replicating improved fit and consistency and demonstrating construct validity and generalizability. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. Interaction Graphs: Exponentials

    OpenAIRE

    Seiller, Thomas

    2013-01-01

    This paper is the fourth of a series exposing a systematic combinatorial approach to Girard's Geometry of Interaction program. This program aims at obtaining particular realizability models for linear logic that accounts for the dynamics of cut-elimination. This fourth paper tackles the complex issue of defining exponential connectives in this framework. In order to succeed in this, we use the notion of graphings, a generalization of graphs which was defined in earlier work. We explain how we...

  5. Coarse Grained Exponential Variational Autoencoders

    KAUST Repository

    Sun, Ke

    2017-02-25

    Variational autoencoders (VAE) often use Gaussian or category distribution to model the inference process. This puts a limit on variational learning because this simplified assumption does not match the true posterior distribution, which is usually much more sophisticated. To break this limitation and apply arbitrary parametric distribution during inference, this paper derives a \\\\emph{semi-continuous} latent representation, which approximates a continuous density up to a prescribed precision, and is much easier to analyze than its continuous counterpart because it is fundamentally discrete. We showcase the proposition by applying polynomial exponential family distributions as the posterior, which are universal probability density function generators. Our experimental results show consistent improvements over commonly used VAE models.

  6. Exponential Expansion in Evolutionary Economics

    DEFF Research Database (Denmark)

    Frederiksen, Peter; Jagtfelt, Tue

    2013-01-01

    to this problem is proposed in the form of a model of exponential expansion. The model outlines the overall structure and function of the economy as exponential expansion. The pictographic model describes four axiomatic concepts and their exponential nature. The interactive, directional, emerging and expanding...

  7. Observed Family Interactions among Subtypes of Eating Disorders Using Structural Analysis of Social Behavior.

    Science.gov (United States)

    Humphrey, Laura Lynn

    1989-01-01

    Compared observations of family interactions among anorexic, bulimic-anorexic, bulimic, and normal families (N=74 families) consisting of father, mother, and teenage daughter. Benjamin's structural analysis of social behavior methodology differentiated clinical from normal families. Found unique patterns among subtypes of eating disorders which…

  8. Test Exponential Pile

    Science.gov (United States)

    Fermi, Enrico

    The Patent contains an extremely detailed description of an atomic pile employing natural uranium as fissile material and graphite as moderator. It starts with the discussion of the theory of the intervening phenomena, in particular the evaluation of the reproduction or multiplication factor, K, that is the ratio of the number of fast neutrons produced in one generation by the fissions to the original number of fast neutrons, in a system of infinite size. The possibility of having a self-maintaining chain reaction in a system of finite size depends both on the facts that K is greater than unity and the overall size of the system is sufficiently large to minimize the percentage of neutrons escaping from the system. After the description of a possible realization of such a pile (with many detailed drawings), the various kinds of neutron losses in a pile are depicted. Particularly relevant is the reported "invention" of the exponential experiment: since theoretical calculations can determine whether or not a chain reaction will occur in a give system, but can be invalidated by uncertainties in the parameters of the problem, an experimental test of the pile is proposed, aimed at ascertaining if the pile under construction would be divergent (i.e. with a neutron multiplication factor K greater than 1) by making measurements on a smaller pile. The idea is to measure, by a detector containing an indium foil, the exponential decrease of the neutron density along the length of a column of uranium-graphite lattice, where a neutron source is placed near its base. Such an exponential decrease is greater or less than that expected due to leakage, according to whether the K factor is less or greater than 1, so that this experiment is able to test the criticality of the pile, its accuracy increasing with the size of the column. In order to perform this measure a mathematical description of the effect of neutron production, diffusion, and absorption on the neutron density in the

  9. Multivariate Matrix-Exponential Distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    2010-01-01

    be written as linear combinations of the elements in the exponential of a matrix. For this reason we shall refer to multivariate distributions with rational Laplace transform as multivariate matrix-exponential distributions (MVME). The marginal distributions of an MVME are univariate matrix......-exponential distributions. We prove a characterization that states that a distribution is an MVME distribution if and only if all non-negative, non-null linear combinations of the coordinates have a univariate matrix-exponential distribution. This theorem is analog to a well-known characterization theorem...

  10. Dynamic Diffusion Estimation in Exponential Family Models

    Czech Academy of Sciences Publication Activity Database

    Dedecius, Kamil; Sečkárová, Vladimíra

    2013-01-01

    Roč. 20, č. 11 (2013), s. 1114-1117 ISSN 1070-9908 R&D Projects: GA MŠk 7D12004; GA ČR GA13-13502S Keywords : diffusion estimation * distributed estimation * paremeter estimation Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.639, year: 2013 http://library.utia.cas.cz/separaty/2013/AS/dedecius-0396518.pdf

  11. Transverse exponential stability and applications

    NARCIS (Netherlands)

    Andrieu, Vincent; Jayawardhana, Bayu; Praly, Laurent

    2016-01-01

    We investigate how the following properties are related to each other: i) A manifold is “transversally” exponentially stable; ii) The “transverse” linearization along any solution in the manifold is exponentially stable; iii) There exists a field of positive definite quadratic forms whose

  12. Housing Services for Child Welfare-Involved Families: An Initial Evaluation Using Observational Data

    Science.gov (United States)

    Fowler, Patrick J.; Taylor, Jeremy J.; Rufa, Anne K.

    2011-01-01

    This study evaluated the impact of housing services among child welfare-involved families using observational data. Propensity score matching with data from the National Survey of Child and Adolescent Well-Being compared intact families (n = 183) who received housing services 12 months after initial investigation to nontreated families balanced on…

  13. Bilateral matrix-exponential distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Esparza, Luz Judith R; Nielsen, Bo Friis

    2012-01-01

    In this article we define the classes of bilateral and multivariate bilateral matrix-exponential distributions. These distributions have support on the entire real space and have rational moment-generating functions. These distributions extend the class of bilateral phasetype distributions of [1]....... As an application we demonstrate that certain multivariate disions, which are governed by the underlying Markov jump process generating a phasetype distribution, have a bilateral matrix-exponential distribution at the time of absorption, see also [4]....

  14. Gross feature of hadronic interactions at 1014-1015eV through the observation of gamma ray families

    International Nuclear Information System (INIS)

    Semba, H.

    1982-01-01

    The decascading method was applied to the gamma ray families observed in Chacaltaya emulsion chambers. Results are compared with decascaded families of Mt.Fuji experiment. The method is found powerful to analyse the air families in this energy range

  15. On commuting operator exponentials, II

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 123; Issue 1. On Commuting Operator Exponentials, II. Fotios C Paliogiannis. Volume 123 Issue 1 February 2013 pp 27-31. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/pmsc/123/01/0027-0031. Keywords.

  16. The exponentiated generalized Pareto distribution | Adeyemi | Ife ...

    African Journals Online (AJOL)

    Recently Gupta et al. (1998) introduced the exponentiated exponential distribution as a generalization of the standard exponential distribution. In this paper, we introduce a three-parameter generalized Pareto distribution, the exponentiated generalized Pareto distribution (EGP). We present a comprehensive treatment of the ...

  17. Science in an Exponential World

    Science.gov (United States)

    Szalay, Alexander

    The amount of scientific information is doubling every year. This exponential growth is fundamentally changing every aspect of the scientific process - the collection, analysis and dissemination of scientific information. Our traditional paradigm for scientific publishing assumes a linear world, where the number of journals and articles remains approximately constant. The talk presents the challenges of this new paradigm and shows examples of how some disciplines are trying to cope with the data avalanche. In astronomy, the Virtual Observatory is emerging as a way to do astronomy in the 21st century. Other disciplines are also in the process of creating their own Virtual Observatories, on every imaginable scale of the physical world. We will discuss how long this exponential growth can continue.

  18. Exponential inflation with F (R ) gravity

    Science.gov (United States)

    Oikonomou, V. K.

    2018-03-01

    In this paper, we shall consider an exponential inflationary model in the context of vacuum F (R ) gravity. By using well-known reconstruction techniques, we shall investigate which F (R ) gravity can realize the exponential inflation scenario at leading order in terms of the scalar curvature, and we shall calculate the slow-roll indices and the corresponding observational indices, in the context of slow-roll inflation. We also provide some general formulas of the slow-roll and the corresponding observational indices in terms of the e -foldings number. In addition, for the calculation of the slow-roll and of the observational indices, we shall consider quite general formulas, for which it is not necessary for the assumption that all the slow-roll indices are much smaller than unity to hold true. Finally, we investigate the phenomenological viability of the model by comparing it with the latest Planck and BICEP2/Keck-Array observational data. As we demonstrate, the model is compatible with the current observational data for a wide range of the free parameters of the model.

  19. Exponentially Stabilizing Robot Control Laws

    Science.gov (United States)

    Wen, John T.; Bayard, David S.

    1990-01-01

    New class of exponentially stabilizing laws for joint-level control of robotic manipulators introduced. In case of set-point control, approach offers simplicity of proportion/derivative control architecture. In case of tracking control, approach provides several important alternatives to completed-torque method, as far as computational requirements and convergence. New control laws modified in simple fashion to obtain asymptotically stable adaptive control, when robot model and/or payload mass properties unknown.

  20. Exponential asymptotics of homoclinic snaking

    Science.gov (United States)

    Dean, A. D.; Matthews, P. C.; Cox, S. M.; King, J. R.

    2011-12-01

    We study homoclinic snaking in the cubic-quintic Swift-Hohenberg equation (SHE) close to the onset of a subcritical pattern-forming instability. Application of the usual multiple-scales method produces a leading-order stationary front solution, connecting the trivial solution to the patterned state. A localized pattern may therefore be constructed by matching between two distant fronts placed back-to-back. However, the asymptotic expansion of the front is divergent, and hence should be truncated. By truncating optimally, such that the resultant remainder is exponentially small, an exponentially small parameter range is derived within which stationary fronts exist. This is shown to be a direct result of the 'locking' between the phase of the underlying pattern and its slowly varying envelope. The locking mechanism remains unobservable at any algebraic order, and can only be derived by explicitly considering beyond-all-orders effects in the tail of the asymptotic expansion, following the method of Kozyreff and Chapman as applied to the quadratic-cubic SHE (Chapman and Kozyreff 2009 Physica D 238 319-54, Kozyreff and Chapman 2006 Phys. Rev. Lett. 97 44502). Exponentially small, but exponentially growing, contributions appear in the tail of the expansion, which must be included when constructing localized patterns in order to reproduce the full snaking diagram. Implicit within the bifurcation equations is an analytical formula for the width of the snaking region. Due to the linear nature of the beyond-all-orders calculation, the bifurcation equations contain an analytically indeterminable constant, estimated in the previous work by Chapman and Kozyreff using a best fit approximation. A more accurate estimate of the equivalent constant in the cubic-quintic case is calculated from the iteration of a recurrence relation, and the subsequent analytical bifurcation diagram compared with numerical simulations, with good agreement.

  1. Exponential asymptotics of homoclinic snaking

    International Nuclear Information System (INIS)

    Dean, A D; Matthews, P C; Cox, S M; King, J R

    2011-01-01

    We study homoclinic snaking in the cubic-quintic Swift–Hohenberg equation (SHE) close to the onset of a subcritical pattern-forming instability. Application of the usual multiple-scales method produces a leading-order stationary front solution, connecting the trivial solution to the patterned state. A localized pattern may therefore be constructed by matching between two distant fronts placed back-to-back. However, the asymptotic expansion of the front is divergent, and hence should be truncated. By truncating optimally, such that the resultant remainder is exponentially small, an exponentially small parameter range is derived within which stationary fronts exist. This is shown to be a direct result of the 'locking' between the phase of the underlying pattern and its slowly varying envelope. The locking mechanism remains unobservable at any algebraic order, and can only be derived by explicitly considering beyond-all-orders effects in the tail of the asymptotic expansion, following the method of Kozyreff and Chapman as applied to the quadratic-cubic SHE (Chapman and Kozyreff 2009 Physica D 238 319–54, Kozyreff and Chapman 2006 Phys. Rev. Lett. 97 44502). Exponentially small, but exponentially growing, contributions appear in the tail of the expansion, which must be included when constructing localized patterns in order to reproduce the full snaking diagram. Implicit within the bifurcation equations is an analytical formula for the width of the snaking region. Due to the linear nature of the beyond-all-orders calculation, the bifurcation equations contain an analytically indeterminable constant, estimated in the previous work by Chapman and Kozyreff using a best fit approximation. A more accurate estimate of the equivalent constant in the cubic-quintic case is calculated from the iteration of a recurrence relation, and the subsequent analytical bifurcation diagram compared with numerical simulations, with good agreement

  2. Family Presence During Resuscitation (FPDR): Observational case studies of emergency personnel in Victoria, Australia.

    Science.gov (United States)

    Porter, Joanne E; Miller, Nareeda; Giannis, Anita; Coombs, Nicole

    2017-07-01

    Family Presence During Resuscitation (FPDR), although not a new concept, remains inconsistently implemented by emergency personnel. Many larger metropolitan emergency departments (ED) have instigated a care coordinator role, however these personnel are often from a non-nursing background and have therefore limited knowledge about the clinical aspects of the resuscitation. In rural emergency departments there are simply not enough staff to allocate an independent role. A separate care coordinator role, who is assigned to care for the family and not take part in the resuscitation has been well documented as essential to the successful implementation of FPDR. One rural and one metropolitan emergency department in the state of Victoria, Australia were observed and data was collected on FPDR events. The participants consisted of resuscitation team members, including; emergency trained nurses, senior medical officers, general nurses and doctors. The participants were not told that the data would be recorded around interactions with family members or team discussions regarding family involvement in the resuscitation, following ethical approval involving limited disclosure of the aims of the study. Seventeen adult presentations (Metro n=9, Rural n=8) were included in this study and will be presented as resuscitation case studies. The key themes identified included ambiguity around resuscitation status, keeping the family informed, family isolation and inter-professional communication. During 17 adult resuscitation cases, staff were witnessed communicating with family, which was often limited and isolation resulted. Family were often uninformed or separated from their family member, however when a family liaison person was available it was found to be beneficial. This research indicated that staff could benefit from a designated family liaison role, formal policy and further education. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The Kumaraswamy G Exponentiated Gumbel type-2 distribution ...

    African Journals Online (AJOL)

    The distribution due to Okorie et al. (2016) is further extended to a wider family of distribution called the Kumaraswamy Generalized Exponentiated Gumbel type-2 distribution. Twenty two distributions are identified as sub-models of the new distribution. Some of its important statistical properties are explicitly derived and the ...

  4. Bivariate copulas on the exponentially weighted moving average control chart

    Directory of Open Access Journals (Sweden)

    Sasigarn Kuvattana

    2016-10-01

    Full Text Available This paper proposes four types of copulas on the Exponentially Weighted Moving Average (EWMA control chart when observations are from an exponential distribution using a Monte Carlo simulation approach. The performance of the control chart is based on the Average Run Length (ARL which is compared for each copula. Copula functions for specifying dependence between random variables are used and measured by Kendall’s tau. The results show that the Normal copula can be used for almost all shifts.

  5. THE PICNIC GAME: PRESENTATION OF A SITUATION OF OBSERVATION TO ASSESS FAMILY INTERACTIONS.

    Science.gov (United States)

    Favez, Nicolas; Frascarolo, France; Grimard, Nathalie

    2016-05-01

    The aim of this article is to present a situation of observation designed for the assessment of family interactions: The PicNic Game (PNG). In this situation, families are invited to play at having a picnic together. This can be done with any number of children, aged from a few weeks to adolescence. A companion assessment tool, the Revised-Picnic Assessment Scale (Re-PAS), allows evaluation of interactions in the family on several dimensions. This article presents the PNG and a preliminary study of the validation of the Re-PAS dimensions in a sample of families (N = 67) with 18-month-old infants and their siblings. The PNG was well-received by the families. Construct validity of the Re-PAS was tested, first against self-reported data by mothers and fathers regarding marital satisfaction, coparenting behavior, and division of household tasks, and then against observed maternal and paternal sensitivity and controlling behaviors assessed during free-play. Results show satisfactory preliminary reliability and validity. Two contrasting cases are presented to illustrate the different interactions highlighted in the PNG. This situation is useful for researchers and clinicians, particularly as a basis for video-feedback work with the family. © 2016 Michigan Association for Infant Mental Health.

  6. Hadron component in families observed with the Mt. Fuji thick type emulsion chamber

    International Nuclear Information System (INIS)

    Konishi, Eiichi

    1978-01-01

    Analysis of hadron component was made on the families detected with the thick type emulsion chamber exposed at Mt. Fuji. The thickness of the emulsion chamber was 70 c.u of Pb. The collecting power was 17 m 2 year. The character of hadrons in the families and their correlations with accompanying gamma-rays are shown. The energy spectra of ten families with number of gamma-ray not less than 5, gamma energy sum not less than 20 TeV and number of Pb jet not less than 5 minimum energy = 2 TeV, and their lateral distribution were investigated. These thick type emulsion chamber data are useful for the analysis of gamma-ray families observed by the thin type emulsion chamber. (Yoshimori, M.)

  7. The PARENTED Outline for Observing Hospitalized Pediatric Patients and Their Families.

    Science.gov (United States)

    Tremain, Amy L

    2017-05-01

    The PARENTED outline (a mnemonic device) and the companion Parenting Landscape handout are proposed tools for clinical use that were developed as an outgrowth of clinical experience with hospitalized pediatric mental health patients and their families in combination with family systems theories of Minuchin and Bowen, Ainsworth and Bowlby's attachment theory, and Erikson's stages of development. The tools contain eight categories of observable, typical family interactions that a nurse on an inpatient mental health unit may encounter. In mnemonic format, the categories are easy to remember so nursing staff can spontaneously interact with pediatric patients and their families while formulating purposeful, organized observations and watching for important family dynamics. Other treatment team members can benefit from this theory-based observation approach because the tools help generate descriptive details for documentation that are available to the entire team. The tools can be shared with veteran staff and new nurses during orientation. [Journal of Psychosocial Nursing and Mental Health Services, 55(5), 51-56.]. Copyright 2017, SLACK Incorporated.

  8. High-order commutator-free quasi-Magnus exponential integrators for non-autonomous linear evolution equations

    Science.gov (United States)

    Blanes, Sergio; Casas, Fernando; Thalhammer, Mechthild

    2017-11-01

    The class of commutator-free quasi-Magnus (CFQM) exponential integrators provides a favourable alternative to standard Magnus integrators, in particular for large-scale applications arising in the time integration of non-autonomous linear evolution equations. The schemes are given by compositions of several exponentials that comprise certain linear combinations of the values of the defining operator at specified nodes. Due to the fact that previously proposed CFQM exponential integrators of order five or higher involve negative coefficients in the linear combinations, severe instabilities are observed for spatially semi-discretised parabolic equations or for master equations describing dissipative quantum systems. In order to remedy this issue, two different approaches for the design of efficient time integrators of orders four, five, and six are pursued: (i) the study of CFQM exponential integrators involving complex coefficients that satisfy a positivity condition, and (ii) the study of unconventional methods in the sense that an additional exponential involving a commutator of higher order with respect to the time stepsize occurs. Numerical experiments confirm that the identified novel time integrators are superior to other integrators of the same family previously proposed in the literature.

  9. Observability of Standard Model Fourth Family Quarks at CERN-LHC

    CERN Document Server

    Arik, E; Conka, T; Mailov, A; Sultansoy, A

    1999-01-01

    We have studied the possible decay channels in which the fourth family quarks will be observed in ATLAS detector. We have also discussed the topological event properties useful for identification the signals of the heavy fourth generation up and down quarks in the experiment.

  10. Differentiating Bulimic-Anorexic from Normal Families Using Interpersonal and Behavioral Observational Systems.

    Science.gov (United States)

    Humphrey, Laura Lynn; And Others

    1986-01-01

    Compared interpersonal and behavioral observational systems in their ability to differentiate families with a bulimic-anorexic daughter using the modified Marital Interaction Coding System (MICS) and the Structural Analysis of Social Behavior (SASB). Results showed both measures successfully discriminated between groups, accounting for…

  11. Cosmological solutions in multidimensional model with multiple exponential potential

    International Nuclear Information System (INIS)

    Ivashchuk, Vladimir D.; Melnikov, Vitaly N.; Selivanov, Alexey B.

    2003-01-01

    A family of cosmological solutions with (n+1) Ricci-flat spaces in the theory with several scalar fields and multiple exponential potential is obtained when coupling vectors in exponents obey certain relations. Two subclasses of solutions with power-law and exponential behaviour of scale factors are singled out. It is proved that power-law solutions may take place only when coupling vectors are linearly independent and exponential dependence occurs for linearly dependent set of coupling vectors. A subfamily of solutions with accelerated expansion is singled out. A generalized isotropization behaviours of certain classes of general solutions are found. In quantum case exact solutions to Wheeler-DeWitt equation are obtained and special 'ground state' wave functions are considered. (author)

  12. Direction-dependent exponential biassing

    International Nuclear Information System (INIS)

    Bending, R.C.

    1974-01-01

    When Monte Carlo methods are applied to penetration problems, the use of variance reduction techniques is essential if realistic computing times are to be achieved. A technique known as direction-dependent exponential biassing is described which is simple to apply and therefore suitable for problems with difficult geometry. The material cross section in any region is multiplied by a factor which depends on the particle direction, so that particles travelling in a preferred direction ''see'' a smaller cross section than those travelling in the opposite direction. A theoretical study shows that substantial gains may be obtained, and that the choice of biassing parameter is not critical. The method has been implemented alongside other importance sampling techniques in the general Monte Carlo code SPARTAN, and results obtained for simple problems using this code are included. 4 references. (U.S.)

  13. Deathbed visions from the Republic of Moldova: a content analysis of family observations.

    Science.gov (United States)

    Kellehear, Allan; Pogonet, Vadim; Mindruta-Stratan, Rodica; Gorelco, Victor

    This is an interview-based study of 102 families and their observations of the last weeks and days of a dying family member. Forty-one families reported hearing about "visions," "hallucinations," or "dreams" from their dying loved one before their death. Of these 41 mixed cases, 37 cases demonstrated classic features of deathbed visions-reports of seeing dead relatives or friends communicating to the dying person. This article reports a content analysis of these 37 cases in order to identify the major psychosocial themes that seem to be conveyed by these kinds of experiences. Six major themes are identified. These themes are: support, comfort, companionship, reunion, prognosis, and choice and control. Implications of these themes are discussed in relation to their role in providing significant support for the psychological morale and social well being of dying people.

  14. [Nobody wants to lose a child--nurses' observations of family reactions].

    Science.gov (United States)

    de Souza, L J; Barroso, M G

    1997-01-01

    The presence of veterinary products in the houses without any minimum security procedures has led to a poisoning case for a one-year old child who developed a serious systemic reaction. This child was interned at a Pediatric Intensive Care Unit at a public hospital in Fortaleza, Ceara. This study aims at identifying the family reaction facing a poisoning of a child and analyzing these reactions, interpreting its social cultural context. It has been developed as an ethnographic study case, consisting of the exploration, decision and discovery phases. It has been observed through the results that the family recognizes the existence of risk factors in home environment but does not adopt any coherent preventive methods with this experience. We do believe that these occurrences reduction demand transforming educative actions which may lead the family to be conscious towards the problematic that concerns poisoning for children, occurred under their responsibility.

  15. Revertant mosaicism for family mutations is not observed in BRCA1/2 phenocopies.

    Directory of Open Access Journals (Sweden)

    Jacopo Azzollini

    Full Text Available In BRCA1/2 families, early-onset breast cancer (BrCa cases may be also observed among non-carrier relatives. These women are considered phenocopies and raise difficult counselling issues concerning the selection of the index case and the residual risks estimate in negative family members. Few studies investigated the presence of potential genetic susceptibility factors in phenocopies, mainly focussing on BrCa-associated single-nucleotide polymorphisms. We hypothesized that, as for other Mendelian diseases, a revertant somatic mosaicism, resulting from spontaneous correction of a pathogenic mutation, might occur also in BRCA pedigrees. A putative low-level mosaicism in phenocopies, which has never been investigated, might be the causal factor undetected by standard diagnostic testing. We selected 16 non-carriers BrCa-affected from 15 BRCA1/2 families, and investigated the presence of mosaicism through MALDI-TOF mass spectrometry. The analyses were performed on available tumour samples (7 cases, blood leukocytes, buccal mucosa and urine samples (2 cases or on blood only (7 cases. In one family (n.8, real-time PCR was also performed to analyse the phenocopy and her healthy parents. On the 16 phenocopies we did not detect the family mutations neither in the tumour, expected to display the highest mutation frequency, nor in the other analysed tissues. In family 8, all the genotyping assays did not detect mosaicism in the phenocopy or her healthy parents, supporting the hypothesis of a de novo occurrence of the BRCA2 mutation identified in the proband. These results suggest that somatic mosaicism is not likely to be a common phenomenon in BRCA1/2 families. As our families fulfilled high-risk selection criteria, other genetic factors might be responsible for most of these cases and have a significant impact on risk assessment in BRCA1/2 families. Finally, we found a de novo BRCA2 mutation, suggesting that, although rare, this event should be taken into

  16. Thermal Characterizations of Exponential Fin Systems

    Directory of Open Access Journals (Sweden)

    A.-R. A. Khaled

    2010-01-01

    Full Text Available Exponential fins are mathematically analyzed in this paper. Two types are considered: (i straight exponential fins and (ii pin exponential fins. The possibility of having increasing or decreasing cross-sectional areas is considered. Different thermal performance indicators are derived. The maximum ratio between the thermal efficiency of the exponential straight fin to that of the rectangular fin is found to be 1.58 at an effective thermal length of 2.0. This ratio is even larger when exponential fins are compared with triangular and parabolic straight fins. Moreover, the maximum ratio between the thermal efficiency of the exponential pin fin to that of the rectangular pin fin is found to be 1.17 at an effective thermal length of 1.5. However, exponential pin fins thermal efficiencies are found to be lower than those of triangular and parabolic pin fins. Moreover, exponential joint-fins may transfer more heat than rectangular joint-fins especially when differences between their senders and receivers portions dimensionless indices are very large. Finally, it is found that increasing the joint-fin exponential index may cause straight exponential joint-fins to transfer more heat than rectangular joint-fins.

  17. Exponential Stabilization of Underactuated Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, K.Y.

    1996-12-31

    Underactuated vehicles are vehicles with fewer independent control actuators than degrees of freedom to be controlled. Such vehicles may be used in inspection of sub-sea cables, inspection and maintenance of offshore oil drilling platforms, and similar. This doctoral thesis discusses feedback stabilization of underactuated vehicles. The main objective has been to further develop methods from stabilization of nonholonomic systems to arrive at methods that are applicable to underactuated vehicles. A nonlinear model including both dynamics and kinematics is used to describe the vehicles, which may be surface vessels, spacecraft or autonomous underwater vehicles (AUVs). It is shown that for a certain class of underactuated vehicles the stabilization problem is not solvable by linear control theory. A new stability result for a class of homogeneous time-varying systems is derived and shown to be an important tool for developing continuous periodic time-varying feedback laws that stabilize underactuated vehicles without involving cancellation of dynamics. For position and orientation control of a surface vessel without side thruster a new continuous periodic feedback law is proposed that does not cancel any dynamics, and that exponentially stabilizes the origin of the underactuated surface vessel. A further issue considered is the stabilization of the attitude of an AUV. Finally, the thesis discusses stabilization of both position and attitude of an underactuated AUV. 55 refs., 28 figs.

  18. Exponential rise of dynamical complexity in quantum computing through projections.

    Science.gov (United States)

    Burgarth, Daniel Klaus; Facchi, Paolo; Giovannetti, Vittorio; Nakazato, Hiromichi; Pascazio, Saverio; Yuasa, Kazuya

    2014-10-10

    The ability of quantum systems to host exponentially complex dynamics has the potential to revolutionize science and technology. Therefore, much effort has been devoted to developing of protocols for computation, communication and metrology, which exploit this scaling, despite formidable technical difficulties. Here we show that the mere frequent observation of a small part of a quantum system can turn its dynamics from a very simple one into an exponentially complex one, capable of universal quantum computation. After discussing examples, we go on to show that this effect is generally to be expected: almost any quantum dynamics becomes universal once 'observed' as outlined above. Conversely, we show that any complex quantum dynamics can be 'purified' into a simpler one in larger dimensions. We conclude by demonstrating that even local noise can lead to an exponentially complex dynamics.

  19. Gross features of nuclear interactions around 1015 eV through observation of gamma ray families

    International Nuclear Information System (INIS)

    Semba, Hiroshi

    1983-01-01

    A systematic analysis is made on the 106 γ-ray families with visible energy in the range of 100--300 TeV observed in the Chacaltaya emulsion chamber experiment. A new method called 'decascading' is introduced to pick up a cluster of γ-rays and electrons in a family, so that the cluster is an air cascade from one parent γ-ray. The application of 'decascading' method to the family data gives information on original γ-rays produced at the atmospheric nuclear interactions. The results are compared with expected ones from the simulation calculation on the base of H-quantum model, and with data from the target interactions at lower energy range (ΣE sub(γ)=20 --100 TeV). The conclusion is that the characteristics of nuclear interactions at the concerned family energy range (E 0 asymptotically equals 1,000 TeV) are in accordance with those at the target interaction range (E 0 asymptotically equals 100 TeV), with increased ratio of frequencies of a heavy fire-ball (SH-quantum) to a small and usual fire-ball (H-quantum). (author)

  20. Two Refreshing Views of Fluctuation Theorems Through Kinematics Elements and Exponential Martingale

    Science.gov (United States)

    Chetrite, Raphaël; Gupta, Shamik

    2011-05-01

    In the context of Markov evolution, we present two original approaches to obtain Generalized Fluctuation-Dissipation Theorems ( GFDT), by using the language of stochastic derivatives and by using a family of exponential martingales functionals. We show that GFDT are perturbative versions of relations verified by these exponential martingales. Along the way, we prove GFDT and Fluctuation Relations ( FR) for general Markov processes, beyond the usual proof for diffusion and pure jump processes. Finally, we relate the FR to a family of backward and forward exponential martingales.

  1. The art of observation: impact of a family medicine and art museum partnership on student education.

    Science.gov (United States)

    Elder, Nancy C; Tobias, Barbara; Lucero-Criswell, Amber; Goldenhar, Linda

    2006-06-01

    Compared to verbal communication, teaching the skill of observation is often shortchanged in medical education. Through a family medicine-art museum collaboration, we developed an elective course for second-year medical students titled the "Art of Observation" (AOO). To evaluate the course's effect on clinical skills, we performed a qualitative evaluation of former students during their clinical rotations. In the spring of 2005, all students who had completed the AOO course in 2003 or 2004 were invited to take part in an online evaluation consisting of eight journaling survey questions. Students were instructed to answer the survey questions with specific examples. Question areas included the most memorable experience, the course's influence on the doctor-patient relationship, usefulness during clinical years of medical school, and skills unique to AOO. The anonymous data were analyzed qualitatively, coding the responses to categories derived from the data, leading to the formation of themes. Of the 19 students eligible, 17 participated. We found three important themes: (1) the AOO positively influenced clinical skills, (2) both art museum exercises and a clinical preceptorship were necessary to achieve those skills, and (3) the AOO led to a sense of personal development as a physician. In addition, students told us that the training in observation and description skills they learned were unique to the AOO. This collaboration between a department of family medicine and an art museum produced a course that facilitated observational skills used in successful doctor-patient relationships.

  2. Development of the General Parenting Observational Scale to assess parenting during family meals.

    Science.gov (United States)

    Rhee, Kyung E; Dickstein, Susan; Jelalian, Elissa; Boutelle, Kerri; Seifer, Ronald; Wing, Rena

    2015-04-10

    There is growing interest in the relationship between general parenting and childhood obesity. However, assessing general parenting via surveys can be difficult due to issues with self-report and differences in the underlying constructs being measured. As a result, different aspects of parenting have been associated with obesity risk. We developed a more objective tool to assess general parenting by using observational methods during a mealtime interaction. The General Parenting Observational Scale (GPOS) was based on prior work of Baumrind, Maccoby and Martin, Barber, and Slater and Power. Ten dimensions of parenting were included; 4 were classified in the emotional dimension of parenting (warmth and affection, support and sensitivity, negative affect, detachment), and 6 were classified in the behavioral dimension of parenting (firm discipline and structure, demands for maturity, psychological control, physical control, permissiveness, neglect). Overweight children age 8-12 years old and their parent (n = 44 dyads) entering a weight control program were videotaped eating a family meal. Parents were coded for their general parenting behaviors. The Mealtime Family Interaction Coding System (MICS) and several self-report measures of general parenting were also used to assess the parent-child interaction. Spearman's correlations were used to assess correlation between measures. The emotional dimensions of warmth/affection and support/sensitivity, and the behavioral dimension of firm discipline/structure were robustly captured during the family meals. Warmth/affection and support/sensitivity were significantly correlated with affect management, interpersonal involvement, and communication from the MICS. Firm discipline/structure was inversely correlated with affect management, behavior control, and task accomplishment. Parents who were older, with higher educational status, and lower BMIs were more likely to display warmth/affection and support/sensitivity. Several

  3. Fat, sugar and water intakes among families from the IDEFICS intervention and control groups: first observations from I.Family.

    Science.gov (United States)

    Arvidsson, L; Bogl, L-H; Eiben, G; Hebestreit, A; Nagy, P; Tornaritis, M; Moreno, L A; Siani, A; Veidebaum, T; De Henauw, S; Lissner, L

    2015-12-01

    The objective of this paper is to investigate differences in diets of families in intervention versus control communities 5 years after the Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants intervention ended. Altogether, 4,691 families from the I.Family study with at least one participating parent and one child are included in this analysis. Diet quality indicators, defined as propensities to consume fat, sugar, water and fruit and vegetables, are calculated from a 59-item food frequency questionnaire. Multilevel linear models with random intercepts for study centre are used to determine whether mean diet indicators, calculated at the family level, differed as a function of previous exposure to the intervention. Families in the intervention communities reported a significantly lower sugar propensity (19.8% vs. 20.7% of total food items, p beverages, p sustainability of some aspects of the diet intervention. © 2015 World Obesity.

  4. Late-time acceleration with steep exponential potentials

    Science.gov (United States)

    Shahalam, M.; Yang, Weiqiang; Myrzakulov, R.; Wang, Anzhong

    2017-12-01

    In this letter, we study the cosmological dynamics of steeper potential than exponential. Our analysis shows that a simple extension of an exponential potential allows to capture late-time cosmic acceleration and retain the tracker behavior. We also perform statefinder and Om diagnostics to distinguish dark energy models among themselves and with Λ CDM. In addition, to put the observational constraints on the model parameters, we modify the publicly available CosmoMC code and use an integrated data base of baryon acoustic oscillation, latest Type Ia supernova from Joint Light Curves sample and the local Hubble constant value measured by the Hubble Space Telescope.

  5. Late-time acceleration with steep exponential potentials

    Energy Technology Data Exchange (ETDEWEB)

    Shahalam, M. [Zhejiang University of Technology, Institute for Advanced Physics and Mathematics, Hangzhou (China); Yang, Weiqiang [Liaoning Normal University, Department of Physics, Dalian (China); Myrzakulov, R. [Eurasian National University, Department of General and Theoretical Physics, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan); Wang, Anzhong [Zhejiang University of Technology, Institute for Advanced Physics and Mathematics, Hangzhou (China); Baylor University, GCAP-CASPER, Department of Physics, Waco, TX (United States)

    2017-12-15

    In this letter, we study the cosmological dynamics of steeper potential than exponential. Our analysis shows that a simple extension of an exponential potential allows to capture late-time cosmic acceleration and retain the tracker behavior. We also perform statefinder and Om diagnostics to distinguish dark energy models among themselves and with ΛCDM. In addition, to put the observational constraints on the model parameters, we modify the publicly available CosmoMC code and use an integrated data base of baryon acoustic oscillation, latest Type Ia supernova from Joint Light Curves sample and the local Hubble constant value measured by the Hubble Space Telescope. (orig.)

  6. Late-time acceleration with steep exponential potentials

    International Nuclear Information System (INIS)

    Shahalam, M.; Yang, Weiqiang; Myrzakulov, R.; Wang, Anzhong

    2017-01-01

    In this letter, we study the cosmological dynamics of steeper potential than exponential. Our analysis shows that a simple extension of an exponential potential allows to capture late-time cosmic acceleration and retain the tracker behavior. We also perform statefinder and Om diagnostics to distinguish dark energy models among themselves and with ΛCDM. In addition, to put the observational constraints on the model parameters, we modify the publicly available CosmoMC code and use an integrated data base of baryon acoustic oscillation, latest Type Ia supernova from Joint Light Curves sample and the local Hubble constant value measured by the Hubble Space Telescope. (orig.)

  7. Multivariate Marshall and Olkin Exponential Minification Process ...

    African Journals Online (AJOL)

    A stationary bivariate minification process with bivariate Marshall-Olkin exponential distribution that was earlier studied by Miroslav et al [15]is in this paper extended to multivariate minification process with multivariate Marshall and Olkin exponential distribution as its stationary marginal distribution. The innovation and the ...

  8. Multivariate Exponential Autoregressive and Autoregressive Moving ...

    African Journals Online (AJOL)

    Autoregressive (AR) and autoregressive moving average (ARMA) processes with multivariate exponential (ME) distribution are presented and discussed. The theory of positive dependence is used to show that in many cases, multivariate exponential autoregressive (MEAR) and multivariate autoregressive moving average ...

  9. Problem Families and the Circumplex Model: Observational Assessment Using the Clinical Rating Scale (CRS).

    Science.gov (United States)

    Thomas, Volker; Olson, David H.

    1993-01-01

    Examined validity, reliability, and curvilinearity of Clinical Rating Scale and tested scale's ability to discriminate between clinical families and nonclinical families on family cohesion, adaptability, and communication. Data from two groups of problem families and two control groups supported curvilinear hypothesis that problem families are…

  10. [Families of the economic crisis in paediatric Primary Care clinics: descriptive observational study].

    Science.gov (United States)

    Martín Martín, R; Sánchez Bayle, M; Gancedo García, C; Teruel de Francisco, M C; Coullaut López, A

    2016-04-01

    To study the impact of the economic crisis on the families of the children who attend Primary Health Care and its relationship with their socioeconomic status. Observational descriptive study was conducted by analysing the results of 453 questionnaires, given to the parents of children between 1 and 7 years old who attended 4 paediatric clinics in Madrid. The raw data was analysed, and comparisons between groups and multivariate analysis were performed. In the multivariate analysis, the variables related to the non-acquisition of prescribed medication are: lower income level OR=0.118, peconomic crisis is related to unemployment OR=4.079, p=.032, lower educational level R=0.678, p=.042, and income level OR=0.342, peconomic crisis has greater impact on the group with the lowest income level in all analysed variables. The lower educational level and higher number of family members has an impact on the reduction in food expenditure. The fact of being an immigrant has an impact on not receiving the anti-pneumococcal and rotavirus vaccination. Unemployment leads to an increase in health problems in the family. To sum up, the economic crisis has increased inequalities according to socioeconomic status. Copyright © 2015 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

  11. On commuting operator exponentials, II

    Indian Academy of Sciences (India)

    eS = ei BeS. Let {Eλ}λ∈R be the spectral family of B. Since σ(B) is generalized 2π-congruence free, there is a Borel subset of σ(B) such that E( ∩ ( + 2kπ)) = 0 for k = ±1, ±2,... and E(σ (B)\\ ) = 0. Then the bounded Borel function f (t) = eit is one-to-one on. = \\. ⋃ k=0( ∩ ( + 2kπ)) and E( ) = I. Using the Borel functional calculus ...

  12. British Industries Collaborative Exponential Programme. Vol. I. Introduction: Exponential experiments on rods and tubes of natural uranium metal

    International Nuclear Information System (INIS)

    1963-03-01

    The experimental techniques used in the performance of exponential buckling measurements are described. The results are given of buckling measurements on a wide range of graphite lattices in which the fuel elements consisted of rods or tubes of natural uranium metal. The observed buckling values are correlated with theory. (author)

  13. Observations on Copy Number Variations in a Kidney-yang Deficiency Syndrome Family

    Directory of Open Access Journals (Sweden)

    Wei Wei Liu

    2011-01-01

    Full Text Available We have performed an analysis of a family with kidney-yang deficiency syndrome (KDS in order to determine the structural genomic variations through a novel approach designated as “copy number variants” (CNVs. Twelve KDS subjects and three healthy spouses from this family were included in this study. Genomic DNA samples were genotyped utilizing an Affymetrix 100 K single nucleotide polymorphism array, and CNVs were identified by Copy Number Algorithm (CNAT4.0, Affymetrix. Our results demonstrate that 447 deleted and 476 duplicated CNVs are shared among KDS subjects within the family. The homologus ratio of deleted CNVs was as high as 99.78%. One-copy-duplicated CNVs display mid-range homology. For two copies of duplicated CNVs (CNV4, a markedly heterologous ratio was observed. Therefore, with the important exception of CNV4, our data shows that CNVs shared among KDS subjects display typical Mendelian inheritance. A total of 113 genes with established functions were identified from the CNV flanks; significantly enriched genes surrounding CNVs may contribute to certain adaptive benefit. These genes could be classified into categories including: binding and transporter, cell cycle, signal transduction, biogenesis, nerve development, metabolism regulation and immune response. They can also be included into three pathways, that is, signal transduction, metabolic processes and immunological networks. Particularly, the results reported here are consistent with the extensive impairments observed in KDS patients, involving the mass-energy-information-carrying network. In conclusion, this article provides the first set of CNVs from KDS patients that will facilitate our further understanding of the genetic basis of KDS and will allow novel strategies for a rational therapy of this disease.

  14. Two Coexisting Families of Compact Stars: Observational Implications for Millisecond Pulsars

    Science.gov (United States)

    Bhattacharyya, Sudip; Bombaci, Ignazio; Logoteta, Domenico; Thampan, Arun V.

    2017-10-01

    It is usually thought that a single equation of state (EoS) model “correctly” represents cores of all compact stars. Here we emphasize that two families of compact stars, viz., neutron stars and strange stars, can coexist in nature, and that neutron stars can get converted to strange stars through the nucleation process of quark matter in the stellar center. From our fully general relativistic numerical computations of the structures of fast-spinning compact stars, known as millisecond pulsars, we find that such a stellar conversion causes a simultaneous spin-up and decrease in gravitational mass of these stars. This is a new type of millisecond pulsar evolution through a new mechanism, which gives rise to relatively lower mass compact stars with higher spin rates. This could have an implication for the observed mass and spin distributions of millisecond pulsars. Such a stellar conversion can also rescue some massive, spin-supported millisecond pulsars from collapsing into black holes. Besides, we extend the concept of critical mass {M}{cr} for the neutron star sequence to the case of fast-spinning neutron stars, and point out that neutron star EoS models cannot be ruled out by the stellar mass measurement alone. Finally, we emphasize the additional complexity for constraining EoS models, for example, by stellar radius measurements using X-ray observations, if two families of compact stars coexist.

  15. A double exponential model for biochemical oxygen demand.

    Science.gov (United States)

    Mason, Ian G; McLachlan, Robert I; Gérard, Daniel T

    2006-01-01

    Biochemical oxygen demand (BOD) exertion patterns in anaerobically treated farm dairy wastewater were investigated on a laboratory scale. Oxygen uptake was typically characterised by a period of rapid oxygen exertion, a transitional "shoulder" phase and a period of slower activity. A multi-species model, involving rapidly degradable and slowly degradable material, was developed, leading to a double exponential model of BOD exertion as follows:where t is time, BOD(u1)(') and BOD(u2)(') are apparent ultimate BOD (BOD(u)) values, and k(1) and k(2) are rate constants. The model provided an improved description of BOD exertion patterns in anaerobically treated farm dairy wastewater in comparison to a conventional single exponential model, with rapidly degradable rate constant values (k(1)) ranging from 2.74 to 17.36d(-1), whilst slowly degradable rate constant values (k(2)) averaged 0.25d(-1) (range 0.20-0.29). Rapidly and slowly degradable apparent BOD(u) estimates ranged from 20 to 140g/m(3) and 225 to 500g/m(3), respectively, giving total BOD(u) levels of 265-620g/m(3). The mean square error in the curve fitting procedure ranged between 20 and 60g(2)/m(6), with values on average 70% lower (range 31-91%) than those obtained for the single exponential model. When applied to existing data for a range of other wastewaters, the double exponential model demonstrated a superior fit to the conventional single exponential model and provided a marginally better fit than a mixed order model. It is proposed that the presence of rapidly degradable material may be indicated from the value of the first rate constant (k1) and the time to 95% saturation of the first exponential function. Further model development is required to describe observed transitional and lag phases.

  16. Exponential Frequency Spectrum in Magnetized Plasmas

    International Nuclear Information System (INIS)

    Pace, D. C.; Shi, M.; Maggs, J. E.; Morales, G. J.; Carter, T. A.

    2008-01-01

    Measurements of a magnetized plasma with a controlled electron temperature gradient show the development of a broadband spectrum of density and temperature fluctuations having an exponential frequency dependence at frequencies below the ion cyclotron frequency. The origin of the exponential frequency behavior is traced to temporal pulses of Lorentzian shape. Similar exponential frequency spectra are also found in limiter-edge plasma turbulence associated with blob transport. This finding suggests a universal feature of magnetized plasma turbulence leading to nondiffusive, cross-field transport, namely, the presence of Lorentzian shaped pulses

  17. The Existence of Weak D-Pullback Exponential Attractor for Nonautonomous Dynamical System

    Directory of Open Access Journals (Sweden)

    Yongjun Li

    2016-01-01

    Full Text Available First, for a process U(t,τ∣t≥τ, we introduce a new concept, called the weak D-pullback exponential attractor, which is a family of sets M(t∣t≤T, for any T∈R, satisfying the following: (i M(t is compact, (ii M(t is positively invariant, that is, U(t,τM(τ⊂M(t, and (iii there exist k,l>0 such that dist(U(t,τB(τ,M(t≤ke-(t-τ; that is, M(t pullback exponential attracts B(τ. Then we give a method to obtain the existence of weak D-pullback exponential attractors for a process. As an application, we obtain the existence of weak D-pullback exponential attractor for reaction diffusion equation in H01 with exponential growth of the external force.

  18. [Sexual development of children and teenagers in the families deported from Abkhazia (dynamic observation)].

    Science.gov (United States)

    Tsiklauri, M I; Katsitadze, G Z; Abesadze, M Iu

    2006-02-01

    The aim of the study was the evaluation of physical and pubertal development of children from the families deported from Abkhazia who were exposed to significant psycho-somatic stress and prolonged socio-economical infringement. Dynamic observation started in 1998. Children, 9-15 years of age, have been studied. 200 children have been selected by the individualised methods (115 were girls and 85 were boys). In parallel children of appropriate age and gender groups from the local families have been studied. The investigations were conducted according to the generally accepted schemes and tables suggested by Tenner (17), for girls and by V.M. Vedenski (8) for boys, respectively. The analysis of obtained results showed that the total percent of delayed puberty in studying group was 21.4% versus 30.0% in the groups of 1998. Consequently, index of delay in control group was equal to 3.9% (2005) and 5.0% (1998). The group, exceeding the norms of puberty (accelerates) was 4.8% versus 11.2% in control group in comparison with the data of 1998--5.4% versus 15.0%, respectively. It should be concluded that due to the obtained results, comparing with the analogic groups of 1998, the number of delayed puberty has been reduced by approximately 9.0%. The number of cases exceeding the norms of puberty has been decreased slightly.

  19. On the formation of exponential discs

    International Nuclear Information System (INIS)

    Yoshii, Yuzuru; Sommer-Larsen, Jesper

    1989-01-01

    Spiral galaxy discs are characterized by approximately exponential surface luminosity profiles. In this paper the evolutionary equations for a star-forming, viscous disc are solved analytically or semi-analytically. It is shown that approximately exponential stellar surface density profiles result if the viscous time-scale t ν is comparable to the star-formation time scale t * everywhere in the disc. The analytical solutions are used to illuminate further on the issue of why the above mechanism leads to resulting exponential stellar profiles under certain conditions. The sensitivity of the solution to variations of various parameters are investigated and show that the initial gas surface density distribution has to be fairly regular in order that final exponential stellar surface density profiles result. (author)

  20. Exponential attractors for a nonclassical diffusion equation

    Directory of Open Access Journals (Sweden)

    Qiaozhen Ma

    2009-01-01

    Full Text Available In this article, we prove the existence of exponential attractors for a nonclassical diffusion equation in ${H^{2}(Omega}cap{H}^{1}_{0}(Omega$ when the space dimension is less than 4.

  1. Observable-preserving control of quantum dynamics over a family of related systems

    International Nuclear Information System (INIS)

    Rothman, Adam; Ho, T.-S.; Rabitz, Herschel

    2005-01-01

    Quantum control aims at the manipulation of atomic- and molecular-scale dynamics phenomena. An important objective in this regard is the understanding of dynamical control within a family of related quantum systems. To explore this issue, diffeomorphic changes in the system Hamiltonian H(s,t) are introduced by scanning over a homotopy parameter s and then monitoring the control field response needed to maintain the value of a specified target observable. This operation is implemented through a procedure referred to as diffeomorphic modulation under observable-response-preserving homotopy (D-MORPH). The governing D-MORPH differential equation determining the control laser field E(s,t) is shown to explicitly allow for innumerable solutions, with each characterized by the choice of an arbitrary function f(s,t) of s and time t. The presence of f(s,t) in the D-MORPH differential equation makes clear the origin of multiple control fields that produce the same observable objective. A stable algorithm is presented for practical execution of D-MORPH with the only criterion that the Hamiltonian H(s,t) permit reaching the objective over the full domain of s being sampled. Both analytic and numerical examples are presented to illustrate the D-MORPH concept

  2. Central limit theorem and deformed exponentials

    International Nuclear Information System (INIS)

    Vignat, C; Plastino, A

    2007-01-01

    The central limit theorem (CLT) can be ranked among the most important ones in probability theory and statistics and plays an essential role in several basic and applied disciplines, notably in statistical thermodynamics. We show that there exists a natural extension of the CLT from exponentials to so-called deformed exponentials (also denoted as q-Gaussians). Our proposal applies exactly in the usual conditions in which the classical CLT is used. (fast track communication)

  3. Positive-engagement behaviors in observed family interactions: a social relations perspective.

    Science.gov (United States)

    Ackerman, Robert A; Kashy, Deborah A; Donnellan, M Brent; Conger, Rand D

    2011-10-01

    The present study investigates the nature of positive engagement (an interpersonal style characterized by attentiveness, warmth, cooperation, and clear communication) in family interactions involving at least one adolescent. Approximately 400 families (mothers, fathers, and two siblings) were videotaped during brief conflict-resolution discussions that occurred on a yearly basis for 3 years. Coders rated the degree to which each family member was positively engaged with every other family member during the interactions. The social relations model was used to partition variation in positive-engagement behavior into family-level, individual-level, and dyad-level effects. Results demonstrated the importance of family norms and individual factors in determining the expression of positive-engagement behaviors in dyadic family relationships. Moreover, longitudinal analyses indicated that these effects are stable over a 3-year period. Finally, results highlighted the relative distinctiveness of the marital and sibling relationships, as well as the existence of reciprocity within these dyads.

  4. Positive Engagement Behaviors in Observed Family Interactions: A Social Relations Perspective

    Science.gov (United States)

    Ackerman, Robert A.; Kashy, Deborah A.; Donnellan, M. Brent; Conger, Rand D.

    2012-01-01

    The present study investigates the nature of positive engagement (an interpersonal style characterized by attentiveness, warmth, cooperation, and clear communication) in family interactions involving at least one adolescent. Approximately 400 families (mothers, fathers, and two siblings) were videotaped during brief conflict resolution discussions that occurred on a yearly basis for three years. Coders rated the degree to which each family member was positively engaged with every other family member during the interactions. The Social Relations Model was used to partition variation in positive engagement behavior into family-level, individual-level, and dyad-level effects. Results demonstrated the importance of family norms and individual factors in determining the expression of positive engagement behaviors in dyadic family relationships. Moreover, longitudinal analyses indicated that these effects are stable over a three year period. Finally, results highlighted the relative distinctiveness of the marital and sibling relationships, as well as the existence of reciprocity within these dyads. PMID:21875194

  5. The scaling of human mobility by taxis is exponential

    Science.gov (United States)

    Liang, Xiao; Zheng, Xudong; Lv, Weifeng; Zhu, Tongyu; Xu, Ke

    2012-03-01

    As a significant factor in urban planning, traffic forecasting and prediction of epidemics, modeling patterns of human mobility draws intensive attention from researchers for decades. Power-law distribution and its variations are observed from quite a few real-world human mobility datasets such as the movements of banking notes, trackings of cell phone users' locations and trajectories of vehicles. In this paper, we build models for 20 million trajectories with fine granularity collected from more than 10 thousand taxis in Beijing. In contrast to most models observed in human mobility data, the taxis' traveling displacements in urban areas tend to follow an exponential distribution instead of a power-law. Similarly, the elapsed time can also be well approximated by an exponential distribution. Worth mentioning, analysis of the interevent time indicates the bursty nature of human mobility, similar to many other human activities.

  6. Stretched versus compressed exponential kinetics in α-helix folding

    International Nuclear Information System (INIS)

    Hamm, Peter; Helbing, Jan; Bredenbeck, Jens

    2006-01-01

    In a recent paper (J. Bredenbeck, J. Helbing, J.R. Kumita, G.A. Woolley, P. Hamm, α-helix formation in a photoswitchable peptide tracked from picoseconds to microseconds by time resolved IR spectroscopy, Proc. Natl. Acad. Sci USA 102 (2005) 2379), we have investigated the folding of a photo-switchable α-helix with a kinetics that could be fit by a stretched exponential function exp(-(t/τ) β ). The stretching factor β became smaller as the temperature was lowered, a result which has been interpreted in terms of activated diffusion on a rugged energy surface. In the present paper, we discuss under which conditions diffusion problems occur with stretched exponential kinetics (β 1). We show that diffusion problems do have a strong tendency to yield stretched exponential kinetics, yet, that there are conditions (strong perturbation from equilibrium, performing the experiment in the folding direction) under which compressed exponential kinetics would be expected instead. We discuss the kinetics on free energy surfaces predicted by simple initiation-propagation models (zipper models) of α-helix folding, as well as by folding funnel models. We show that our recent experiment has been performed under condition for which models with strong downhill driving force, such as the zipper model, would predict compressed, rather than stretched exponential kinetics, in disagreement with the experimental observation. We therefore propose that the free energy surface along a reaction coordinate that governs the folding kinetics must be relatively flat and has a shape similar to a 1D golf course. We discuss how this conclusion can be unified with the thermodynamically well established zipper model by introducing an additional kinetic reaction coordinate

  7. Methodological considerations for observational coding of eating and feeding behaviors in children and their families.

    Science.gov (United States)

    Pesch, Megan H; Lumeng, Julie C

    2017-12-15

    Behavioral coding of videotaped eating and feeding interactions can provide researchers with rich observational data and unique insights into eating behaviors, food intake, food selection as well as interpersonal and mealtime dynamics of children and their families. Unlike self-report measures of eating and feeding practices, the coding of videotaped eating and feeding behaviors can allow for the quantitative and qualitative examinations of behaviors and practices that participants may not self-report. While this methodology is increasingly more common, behavioral coding protocols and methodology are not widely shared in the literature. This has important implications for validity and reliability of coding schemes across settings. Additional guidance on how to design, implement, code and analyze videotaped eating and feeding behaviors could contribute to advancing the science of behavioral nutrition. The objectives of this narrative review are to review methodology for the design, operationalization, and coding of videotaped behavioral eating and feeding data in children and their families, and to highlight best practices. When capturing eating and feeding behaviors through analysis of videotapes, it is important for the study and coding to be hypothesis driven. Study design considerations include how to best capture the target behaviors through selection of a controlled experimental laboratory environment versus home mealtime, duration of video recording, number of observations to achieve reliability across eating episodes, as well as technical issues in video recording and sound quality. Study design must also take into account plans for coding the target behaviors, which may include behavior frequency, duration, categorization or qualitative descriptors. Coding scheme creation and refinement occur through an iterative process. Reliability between coders can be challenging to achieve but is paramount to the scientific rigor of the methodology. Analysis approach

  8. Separation of type and grade in cervical tumours using non-mono-exponential models of diffusion-weighted MRI

    International Nuclear Information System (INIS)

    Winfield, Jessica M.; Collins, David J.; Morgan, Veronica A.; DeSouza, Nandita M.; Orton, Matthew R.; Ind, Thomas E.J.; Attygalle, Ayoma; Hazell, Steve

    2017-01-01

    Assessment of empirical diffusion-weighted MRI (DW-MRI) models in cervical tumours to investigate whether fitted parameters distinguish between types and grades of tumours. Forty-two patients (24 squamous cell carcinomas, 14 well/moderately differentiated, 10 poorly differentiated; 15 adenocarcinomas, 13 well/moderately differentiated, two poorly differentiated; three rare types) were imaged at 3 T using nine b-values (0 to 800 s mm -2 ). Mono-exponential, stretched exponential, kurtosis, statistical, and bi-exponential models were fitted. Model preference was assessed using Bayesian Information Criterion analysis. Differences in fitted parameters between tumour types/grades and correlation between fitted parameters were assessed using two-way analysis of variance and Pearson's linear correlation coefficient, respectively. Non-mono-exponential models were preferred by 83 % of tumours with bi-exponential and stretched exponential models preferred by the largest numbers of tumours. Apparent diffusion coefficient (ADC) and diffusion coefficients from non-mono-exponential models were significantly lower in poorly differentiated tumours than well/moderately differentiated tumours. α (stretched exponential), K (kurtosis), f and D* (bi-exponential) were significantly different between tumour types. Strong correlation was observed between ADC and diffusion coefficients from other models. Non-mono-exponential models were preferred to the mono-exponential model in DW-MRI data from cervical tumours. Parameters of non-mono-exponential models showed significant differences between types and grades of tumours. (orig.)

  9. Separation of type and grade in cervical tumours using non-mono-exponential models of diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Winfield, Jessica M.; Collins, David J.; Morgan, Veronica A.; DeSouza, Nandita M. [The Royal Marsden NHS Foundation Trust, MRI Unit, Sutton, Surrey (United Kingdom); The Institute of Cancer Research, Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, London (United Kingdom); Orton, Matthew R. [The Institute of Cancer Research, Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, London (United Kingdom); Ind, Thomas E.J. [The Royal Marsden NHS Foundation Trust, Gynaecology Unit, London (United Kingdom); Attygalle, Ayoma; Hazell, Steve [The Royal Marsden NHS Foundation Trust, Department of Histopathology, London (United Kingdom)

    2017-02-15

    Assessment of empirical diffusion-weighted MRI (DW-MRI) models in cervical tumours to investigate whether fitted parameters distinguish between types and grades of tumours. Forty-two patients (24 squamous cell carcinomas, 14 well/moderately differentiated, 10 poorly differentiated; 15 adenocarcinomas, 13 well/moderately differentiated, two poorly differentiated; three rare types) were imaged at 3 T using nine b-values (0 to 800 s mm{sup -2}). Mono-exponential, stretched exponential, kurtosis, statistical, and bi-exponential models were fitted. Model preference was assessed using Bayesian Information Criterion analysis. Differences in fitted parameters between tumour types/grades and correlation between fitted parameters were assessed using two-way analysis of variance and Pearson's linear correlation coefficient, respectively. Non-mono-exponential models were preferred by 83 % of tumours with bi-exponential and stretched exponential models preferred by the largest numbers of tumours. Apparent diffusion coefficient (ADC) and diffusion coefficients from non-mono-exponential models were significantly lower in poorly differentiated tumours than well/moderately differentiated tumours. α (stretched exponential), K (kurtosis), f and D* (bi-exponential) were significantly different between tumour types. Strong correlation was observed between ADC and diffusion coefficients from other models. Non-mono-exponential models were preferred to the mono-exponential model in DW-MRI data from cervical tumours. Parameters of non-mono-exponential models showed significant differences between types and grades of tumours. (orig.)

  10. Family Income, Parent Education, and Perceived Constraints as Predictors of Observed Program Quality and Parent Rated Program Quality

    Science.gov (United States)

    Torquati, Julia C.; Raikes, Helen H.; Huddleston-Casas, Catherine A.; Bovaird, James A.; Harris, Beatrice A.

    2011-01-01

    Observed child care quality and parent perceptions of child care quality received by children in poor (below Federal Poverty Line, FPL), low-income (between FPL and 200% of FPL), and non-low-income families were examined. Observations were completed in 359 center- and home-based child care programs in four Midwestern states and surveys were…

  11. ESTIMATION ACCURACY OF EXPONENTIAL DISTRIBUTION PARAMETERS

    Directory of Open Access Journals (Sweden)

    muhammad zahid rashid

    2011-04-01

    Full Text Available The exponential distribution is commonly used to model the behavior of units that have a constant failure rate. The two-parameter exponential distribution provides a simple but nevertheless useful model for the analysis of lifetimes, especially when investigating reliability of technical equipment.This paper is concerned with estimation of parameters of the two parameter (location and scale exponential distribution. We used the least squares method (LSM, relative least squares method (RELS, ridge regression method (RR,  moment estimators (ME, modified moment estimators (MME, maximum likelihood estimators (MLE and modified maximum likelihood estimators (MMLE. We used the mean square error MSE, and total deviation TD, as measurement for the comparison between these methods. We determined the best method for estimation using different values for the parameters and different sample sizes

  12. When Economic Growth is Less than Exponential

    DEFF Research Database (Denmark)

    Groth, Christian; Koch, Karl-Josef; Steger, Thomas M.

    This paper argues that growth theory needs a more general notion of "regularity" than that of exponential growth. We suggest that paths along which the rate of decline of the growth rate is proportional to the growth rate itself deserve attention. This opens up for considering a richer set...... of parameter combinations than in standard growth models. And it avoids the usual oversimplistic dichotomy of either exponential growth or stagnation. Allowing zero population growth in three different growth models (the Jones R&D-based model, a learning-by-doing model, and an embodied technical change model......) serve as illustrations that a continuum of "regular" growth processes fill the whole range between exponential growth and complete stagnation....

  13. When economic growth is less than exponential

    DEFF Research Database (Denmark)

    Groth, Christian; Koch, Karl-Josef; Steger, Thomas

    2010-01-01

    This paper argues that growth theory needs a more general notion of "regularity" than that of exponential growth. We suggest that paths along which the rate of decline of the growth rate is proportional to the growth rate itself deserve attention. This opens up for considering a richer set...... of parameter combinations than in standard growth models. And it avoids the usual oversimplistic dichotomy of either exponential growth or stagnation. Allowing zero population growth in three different growth models (the Jones R&D-based model, a learning-by-doing model, and an embodied technical change model......) serves as illustration that a continuum of "regular" growth processes fill the whole range between exponential growth and complete stagnation....

  14. The technological singularity and exponential medicine

    Directory of Open Access Journals (Sweden)

    Iraj Nabipour

    2016-01-01

    Full Text Available The "technological singularity" is forecasted to occur in 2045. It is a point when non-biological intelligence becomes more intelligent than humans and each generation of intelligent machines re-designs itself smarter. Beyond this point, there is a symbiosis between machines and humans. This co-existence will produce incredible impacts on medicine that its sparkles could be seen in healthcare industry and the future medicine since 2025. Ray Kurzweil, the great futurist, suggested that three revolutions in science and technology consisting genetic and molecular science, nanotechnology, and robotic (artificial intelligence provided an exponential growth rate for medicine. The "exponential medicine" is going to create more disruptive technologies in healthcare industry. The exponential medicine shifts the paradigm of medical philosophy and produces significant impacts on the healthcare system and patient-physician relationship.   

  15. Quantum Zeno effect for exponentially decaying systems

    International Nuclear Information System (INIS)

    Koshino, Kazuki; Shimizu, Akira

    2004-01-01

    The quantum Zeno effect - suppression of decay by frequent measurements - was believed to occur only when the response of the detector is so quick that the initial tiny deviation from the exponential decay law is detectable. However, we show that it can occur even for exactly exponentially decaying systems, for which this condition is never satisfied, by considering a realistic case where the detector has a finite energy band of detection. The conventional theories correspond to the limit of an infinite bandwidth. This implies that the Zeno effect occurs more widely than expected thus far

  16. Calorimeter prediction based on multiple exponentials

    International Nuclear Information System (INIS)

    Smith, M.K.; Bracken, D.S.

    2002-01-01

    Calorimetry allows very precise measurements of nuclear material to be carried out, but it also requires relatively long measurement times to do so. The ability to accurately predict the equilibrium response of a calorimeter would significantly reduce the amount of time required for calorimetric assays. An algorithm has been developed that is effective at predicting the equilibrium response. This multi-exponential prediction algorithm is based on an iterative technique using commercial fitting routines that fit a constant plus a variable number of exponential terms to calorimeter data. Details of the implementation and the results of trials on a large number of calorimeter data sets will be presented

  17. Exponential Growth of Nonlinear Ballooning Instability

    International Nuclear Information System (INIS)

    Zhu, P.; Hegna, C. C.; Sovinec, C. R.

    2009-01-01

    Recent ideal magnetohydrodynamic (MHD) theory predicts that a perturbation evolving from a linear ballooning instability will continue to grow exponentially in the intermediate nonlinear phase at the same linear growth rate. This prediction is confirmed in ideal MHD simulations. When the Lagrangian compression, a measure of the ballooning nonlinearity, becomes of the order of unity, the intermediate nonlinear phase is entered, during which the maximum plasma displacement amplitude as well as the total kinetic energy continues to grow exponentially at the rate of the corresponding linear phase.

  18. Exponential Data Fitting and its Applications

    CERN Document Server

    Pereyra, Victor

    2010-01-01

    Real and complex exponential data fitting is an important activity in many different areas of science and engineering, ranging from Nuclear Magnetic Resonance Spectroscopy and Lattice Quantum Chromodynamics to Electrical and Chemical Engineering, Vision and Robotics. The most commonly used norm in the approximation by linear combinations of exponentials is the l2 norm (sum of squares of residuals), in which case one obtains a nonlinear separable least squares problem. A number of different methods have been proposed through the years to solve these types of problems and new applications appear

  19. An Exponential Growth Learning Trajectory: Students' Emerging Understanding of Exponential Growth through Covariation

    Science.gov (United States)

    Ellis, Amy B.; Ozgur, Zekiye; Kulow, Torrey; Dogan, Muhammed F.; Amidon, Joel

    2016-01-01

    This article presents an Exponential Growth Learning Trajectory (EGLT), a trajectory identifying and characterizing middle grade students' initial and developing understanding of exponential growth as a result of an instructional emphasis on covariation. The EGLT explicates students' thinking and learning over time in relation to a set of tasks…

  20. The Use of Modeling Approach for Teaching Exponential Functions

    Science.gov (United States)

    Nunes, L. F.; Prates, D. B.; da Silva, J. M.

    2017-12-01

    This work presents a discussion related to the teaching and learning of mathematical contents related to the study of exponential functions in a freshman students group enrolled in the first semester of the Science and Technology Bachelor’s (STB of the Federal University of Jequitinhonha and Mucuri Valleys (UFVJM). As a contextualization tool strongly mentioned in the literature, the modelling approach was used as an educational teaching tool to produce contextualization in the teaching-learning process of exponential functions to these students. In this sense, were used some simple models elaborated with the GeoGebra software and, to have a qualitative evaluation of the investigation and the results, was used Didactic Engineering as a methodology research. As a consequence of this detailed research, some interesting details about the teaching and learning process were observed, discussed and described.

  1. Generalized approach to non-exponential relaxation

    Indian Academy of Sciences (India)

    Abstract. Non-exponential relaxation is a universal feature of systems as diverse as glasses, spin glasses, earthquakes, financial markets and the universe. Complex relaxation results from hierarchically constrained dynamics with the strength of the constraints being directly related to the form of the relaxation, which ...

  2. CKM matrix exponential parametrization and Euler angles

    International Nuclear Information System (INIS)

    Dattoli, G.; Sabia, E.; Torre, A.

    1997-01-01

    They show that the exponential parametrization of the CKM matrix allows to establish exact relations between the Euler weak rotation angles and the entries of the CKM generating matrix, which has already been shown to include the hierarchy features of the Wolfenstein parametrization. The analysis includes CP-violating effects and its usefulness to treat the experimental data is also proved

  3. Exponential function method for solving nonlinear ordinary ...

    Indian Academy of Sciences (India)

    Corresponding author. E-mail: E.A.Chadwick@Salford.ac.uk; alihatam@aut.ac.ir; SaeedKazem@aut.ac.ir. MS received 29 July 2013; revised 14 June 2015. Abstract. A new approach, named the exponential function method (EFM) is used to.

  4. Realistic searches on stretched exponential networks

    Indian Academy of Sciences (India)

    Vol. 71, No. 2. — journal of. August 2008 physics pp. 313–317. Realistic searches on stretched exponential networks. PARONGAMA SEN. Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road,. Kolkata 700 009, India .... [4] S Milgram, Psychology Today 1, 60 (1967). J Travers and S Milgram, ...

  5. Academic Sacred Cows and Exponential Growth.

    Science.gov (United States)

    Heterick, Robert C., Jr.

    1991-01-01

    The speech notes the linear growth of resources versus the exponential growth of costs in higher education. It identifies opportunities arising from information technology to transform teaching and learning through creation of a new scholarly information delivery system. An integrated triad of communications, computing, and library organizations…

  6. Intersection of the Exponential and Logarithmic Curves

    Science.gov (United States)

    Boukas, Andreas; Valahas, Theodoros

    2009-01-01

    The study of the number of intersection points of y = a[superscript x] and y = log[subscript a]x can be an interesting topic to present in a single-variable calculus class. In this article, the authors present a classroom presentation outline involving the basic algebra and the elementary calculus of the exponential and logarithmic functions. The…

  7. Exponential Lower Bounds For Policy Iteration

    OpenAIRE

    Fearnley, John

    2010-01-01

    We study policy iteration for infinite-horizon Markov decision processes. It has recently been shown policy iteration style algorithms have exponential lower bounds in a two player game setting. We extend these lower bounds to Markov decision processes with the total reward and average-reward optimality criteria.

  8. Gamma and Exponential Autoregressive Moving Average (ARMA ...

    African Journals Online (AJOL)

    Time series data encountered in practice depict properties that deviate from those of gaussian processes. The gamma and exponentially distributed processes which are used as basic models for positive time series fall in the class of non-gaussian processes. In this paper, we develop new and simpler representations of the ...

  9. On exponential growth [of gas breakdown

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1991-01-01

    The agreement obtained between measured breakdown voltages and predicted breakdown values is frequently used as a means of assessing the validity of the theory/model in question. However, owing to the mathematical nature of exponential growth, it is easy to formulate a criterion that provides acc...

  10. Particle interactions at energies over 1000 TeV inferred from gamma-families observed at Mount Fuji

    Science.gov (United States)

    Amenomori, M.; Nanjo, H.; Konishi, E.; Hotta, N.; Mizutani, K.; Kasahara, K.; Kobayashi, T.; Mikumo, E.; Sato, K.; Yuda, T.

    1985-01-01

    Scaling, mean P sub t, high P sub t jets and others at energies over 1000 TeV are discussed on the basis of gamma-family data with sigma E sub gamma 100 TeV, observed at Mt. Fuji (3750 m). These quantities were examined in connection with the primary composition.

  11. Exponential power spectra, deterministic chaos and Lorentzian pulses in plasma edge dynamics

    International Nuclear Information System (INIS)

    Maggs, J E; Morales, G J

    2012-01-01

    Exponential spectra have been observed in the edges of tokamaks, stellarators, helical devices and linear machines. The observation of exponential power spectra is significant because such a spectral character has been closely associated with the phenomenon of deterministic chaos by the nonlinear dynamics community. The proximate cause of exponential power spectra in both magnetized plasma edges and nonlinear dynamics models is the occurrence of Lorentzian pulses in the time signals of fluctuations. Lorentzian pulses are produced by chaotic behavior in the separatrix regions of plasma E × B flow fields or the limit cycle regions of nonlinear models. Chaotic advection, driven by the potential fields of drift waves in plasmas, results in transport. The observation of exponential power spectra and Lorentzian pulses suggests that fluctuations and transport at the edge of magnetized plasmas arise from deterministic, rather than stochastic, dynamics. (paper)

  12. Matrix-exponential distributions in applied probability

    CERN Document Server

    Bladt, Mogens

    2017-01-01

    This book contains an in-depth treatment of matrix-exponential (ME) distributions and their sub-class of phase-type (PH) distributions. Loosely speaking, an ME distribution is obtained through replacing the intensity parameter in an exponential distribution by a matrix. The ME distributions can also be identified as the class of non-negative distributions with rational Laplace transforms. If the matrix has the structure of a sub-intensity matrix for a Markov jump process we obtain a PH distribution which allows for nice probabilistic interpretations facilitating the derivation of exact solutions and closed form formulas. The full potential of ME and PH unfolds in their use in stochastic modelling. Several chapters on generic applications, like renewal theory, random walks and regenerative processes, are included together with some specific examples from queueing theory and insurance risk. We emphasize our intention towards applications by including an extensive treatment on statistical methods for PH distribu...

  13. Exponentiated Lomax Geometric Distribution: Properties and Applications

    Directory of Open Access Journals (Sweden)

    Amal Soliman Hassan

    2017-09-01

    Full Text Available In this paper, a new four-parameter lifetime distribution, called the exponentiated Lomax geometric (ELG is introduced. The new lifetime distribution contains the Lomax geometric and exponentiated Pareto geometric as new sub-models. Explicit algebraic formulas of probability density function, survival and hazard functions are derived. Various structural properties of the new model are derived including; quantile function, Re'nyi entropy, moments, probability weighted moments, order statistic, Lorenz and Bonferroni curves. The estimation of the model parameters is performed by maximum likelihood method and inference for a large sample is discussed. The flexibility and potentiality of the new model in comparison with some other distributions are shown via an application to a real data set. We hope that the new model will be an adequate model for applications in various studies.

  14. Exponential Stabilization of an Underactuated Surface Vessel

    Directory of Open Access Journals (Sweden)

    Kristin Y. Pettersen

    1997-07-01

    Full Text Available The paper shows that a large class of underactuated vehicles cannot be asymptotically stabilized by either continuous or discontinuous state feedback. Furthermore, stabilization of an underactuated surface vessel is considered. Controllability properties of the surface vessels is presented, and a continuous periodic time-varying feedback law is proposed. It is shown that this feedback law exponentially stabilizes the surface vessel to the origin, and this is illustrated by simulations.

  15. Exponentially Light Dark Matter from Coannihilation

    OpenAIRE

    D'Agnolo, Raffaele Tito; Mondino, Cristina; Ruderman, Joshua T.; Wang, Po-Jen

    2018-01-01

    Dark matter may be a thermal relic whose abundance is set by mutual annihilations among multiple species. Traditionally, this coannihilation scenario has been applied to weak scale dark matter that is highly degenerate with other states. We show that coannihilation among states with split masses points to dark matter that is exponentially lighter than the weak scale, down to the keV scale. We highlight the regime where dark matter does not participate in the annihilations that dilute its numb...

  16. Graphical analysis for gel morphology II. New mathematical approach for stretched exponential function with β>1

    International Nuclear Information System (INIS)

    Hashimoto, Chihiro; Panizza, Pascal; Rouch, Jacques; Ushiki, Hideharu

    2005-01-01

    A new analytical concept is applied to the kinetics of the shrinking process of poly(N-isopropylacrylamide) (PNIPA) gels. When PNIPA gels are put into hot water above the critical temperature, two-step shrinking is observed and the secondary shrinking of gels is fitted well by a stretched exponential function. The exponent β characterizing the stretched exponential is always higher than one, although there are few analytical concepts for the stretched exponential function with β>1. As a new interpretation for this function, we propose a superposition of step (Heaviside) function and a new distribution function of characteristic time is deduced

  17. Background does not significantly affect power-exponential fitting of gastric emptying curves

    International Nuclear Information System (INIS)

    Jonderko, K.

    1987-01-01

    Using a procedure enabling the assessment of background radiation, research was done to elucidate the course of changes in background activity during gastric emptying measurements. Attention was focused on the changes in the shape of power-exponential fitted gastric emptying curves after correction for background was performed. The observed pattern of background counts allowed to explain the shifts of the parameters characterizing power-exponential curves connected with background correction. It was concluded that background had a negligible effect on the power-exponential fitting of gastric emptying curves. (author)

  18. Unwrapped phase inversion with an exponential damping

    KAUST Repository

    Choi, Yun Seok

    2015-07-28

    Full-waveform inversion (FWI) suffers from the phase wrapping (cycle skipping) problem when the frequency of data is not low enough. Unless we obtain a good initial velocity model, the phase wrapping problem in FWI causes a result corresponding to a local minimum, usually far away from the true solution, especially at depth. Thus, we have developed an inversion algorithm based on a space-domain unwrapped phase, and we also used exponential damping to mitigate the nonlinearity associated with the reflections. We construct the 2D phase residual map, which usually contains the wrapping discontinuities, especially if the model is complex and the frequency is high. We then unwrap the phase map and remove these cycle-based jumps. However, if the phase map has several residues, the unwrapping process becomes very complicated. We apply a strong exponential damping to the wavefield to eliminate much of the residues in the phase map, thus making the unwrapping process simple. We finally invert the unwrapped phases using the back-propagation algorithm to calculate the gradient. We progressively reduce the damping factor to obtain a high-resolution image. Numerical examples determined that the unwrapped phase inversion with a strong exponential damping generated convergent long-wavelength updates without low-frequency information. This model can be used as a good starting model for a subsequent inversion with a reduced damping, eventually leading to conventional waveform inversion.

  19. Method for exponentiating in cryptographic systems

    Energy Technology Data Exchange (ETDEWEB)

    Brickell, E.F.; Gordon, D.M.; McCurley, K.S.

    1992-12-31

    An improved cryptographic method utilizing exponentiation is provided which has the advantage of reducing the number of multiplications required to determine the legitimacy of a message or user. The basic method comprises the steps of selecting a key from a pre-approved group of integer keys g; exponentiating the key by an integer value e, where e represents a digital signature, to generate a value g{sup e}; transmitting the value g{sup e} to a remote facility by a communications network; receiving the value g{sup e} at the remote facility; and verifying the digital signature as originating from the legitimate user. The exponentiating step comprises the steps of initializing a plurality of memory locations with a plurality of values g{sup xi}, computing a{sub i} representations for a integer base b, where a{sub i} represents the weighing factor of the ith digit of the integer e; computing the individual values of c{sub d} according to the rule: c{sub d}={product}a{sub i}=d g{sup x {sub i}}; and computing the product of {product}{sup h}/{sub d=1} c{sub d}{sup d} from the stored values of from the plurality of memory locations so as to determine a value for g{sup e}.

  20. Acceptance of family planning methods by induced abortion seekers: An observational study over five years.

    Science.gov (United States)

    Kathpalia, S K

    2016-01-01

    Prior to legalization of abortion, induced abortions were performed in an illegal manner and that resulted in many complications hence abortion was legalized in India in 1971 and the number of induced abortions has been gradually increasing since then. One way of preventing abortions is to provide family planning services to these abortion seekers so that same is not repeated. The study was performed to find out the acceptance of contraception after abortion. A prospective study was performed over a period of five years from 2010 to 2014. The study group included all the cases reporting for abortion. A proforma was filled in detail to find out the type of contraception being used before pregnancy and acceptance of contraception after abortion. The existing facilities were also evaluated. 1228 abortions were performed over a period of five years. 94.5% of abortions were during the first trimester. 39.9% had not used any contraceptive before, contraceptives used were natural and barrier which had high failure. The main indication for seeking abortion was failure of contraception and completion of family. 39.6% of patients accepted sterilization as a method of contraception. The existing post abortion family planning services are inadequate. Post abortion period is one which is important to prevent subsequent abortions and family planning services after abortion need to be strengthened.

  1. Advantages of long observation in episode-oriented electronic patient records in family practice

    NARCIS (Netherlands)

    Okkes, I. M.; Groen, A.; Oskam, S. K.; Lamberts, H.

    2001-01-01

    From 1985-2000, 58 Dutch family physicians (FPs) of the Transition Project collected ICPC-coded data on 47, 2451 episodes of care, first in paper records for direct encounters only, later with a complete electronic patient record (EPR) for all (direct and indirect) encounters. Based on these data,

  2. Parenting and the Family Check-Up: Changes in Observed Parent-Child Interaction Following Early Childhood Intervention.

    Science.gov (United States)

    Sitnick, Stephanie L; Shaw, Daniel S; Gill, Anne; Dishion, Thomas; Winter, Charlotte; Waller, Rebecca; Gardner, Frances; Wilson, Melvin

    2015-01-01

    Coercion theory posits a cyclical relationship between harsh and coercive parent-child interactions and problem behavior beginning in early childhood. As coercive interactions have been theorized and found to facilitate the development and growth of early conduct problems, early interventions often target parenting to prevent or reduce early disruptive problem behavior. This study utilizes direct observations of parent-child interactions from the Early Steps Multisite study (N = 731; 369 boys) to examine the effect of the Family Check-Up, a family-centered intervention program, on measures of parent-child positive engagement and coercion from age 2 through 5, as well as on childhood problem behavior at age 5. Results indicate that high levels of parent-child positive engagement were associated with less parent-child coercion the following year, but dyadic coercion was unrelated to future levels of positive engagement. In addition, families assigned to the Family Check-Up showed increased levels of positive engagement at ages 3 and 5, and the association between positive engagement at age 3 and child problem behavior at age 5 was mediated by reductions in parent-child coercion at age 4. These findings provide longitudinal confirmation that increasing positive engagement in parent-child interaction can reduce the likelihood of coercive family dynamics in early childhood and growth in problem behavior.

  3. Truncated exponential-rigid-rotor model for strong electron and ion rings

    International Nuclear Information System (INIS)

    Larrabee, D.A.; Lovelace, R.V.; Fleischmann, H.H.

    1979-01-01

    A comprehensive study of exponential-rigid-rotor equilibria for strong electron and ion rings indicates the presence of a sizeable percentage of untrapped particles in all equilibria with aspect-ratios R/a approximately <4. Such aspect-ratios are required in fusion-relevant rings. Significant changes in the equilibria are observed when untrapped particles are excluded by the use of a truncated exponential-rigid-rotor distribution function. (author)

  4. Dynamic Transcriptional Regulation of Fis in Salmonella During the Exponential Phase.

    Science.gov (United States)

    Wang, Hui; Wang, Lei; Li, Ping; Hu, Yilang; Zhang, Wei; Tang, Bo

    2015-12-01

    Fis is one of the most important global regulators and has attracted extensive research attention. Many studies have focused on comparing the Fis global regulatory networks for exploring Fis function during different growth stages, such as the exponential and stationary stages. Although the Fis protein in bacteria is mainly expressed in the exponential phase, the dynamic transcriptional regulation of Fis during the exponential phase remains poorly understood. To address this question, we used RNA-seq technology to identify the Fis-regulated genes in the S. enterica serovar Typhimurium during the early exponential phase, and qRT-PCR was performed to validate the transcriptional data. A total of 1495 Fis-regulated genes were successfully identified, including 987 Fis-repressed genes and 508 Fis-activated genes. Comparing the results of this study with those of our previous study, we found that the transcriptional regulation of Fis was diverse during the early- and mid-exponential phases. The results also showed that the strong positive regulation of Fis on Salmonella pathogenicity island genes in the mid-exponential phase transitioned into insignificant effect in the early exponential phase. To validate these results, we performed a cell infection assay and found that Δfis only exhibited a 1.49-fold decreased capacity compared with the LT2 wild-type strain, indicating a large difference from the 6.31-fold decrease observed in the mid-exponential phase. Our results provide strong evidence for a need to thoroughly understand the dynamic transcriptional regulation of Fis in Salmonella during the exponential phase.

  5. Progressive Exponential Clustering-Based Steganography

    Directory of Open Access Journals (Sweden)

    Li Yue

    2010-01-01

    Full Text Available Cluster indexing-based steganography is an important branch of data-hiding techniques. Such schemes normally achieve good balance between high embedding capacity and low embedding distortion. However, most cluster indexing-based steganographic schemes utilise less efficient clustering algorithms for embedding data, which causes redundancy and leaves room for increasing the embedding capacity further. In this paper, a new clustering algorithm, called progressive exponential clustering (PEC, is applied to increase the embedding capacity by avoiding redundancy. Meanwhile, a cluster expansion algorithm is also developed in order to further increase the capacity without sacrificing imperceptibility.

  6. Finite difference computing with exponential decay models

    CERN Document Server

    Langtangen, Hans Petter

    2016-01-01

    This text provides a very simple, initial introduction to the complete scientific computing pipeline: models, discretization, algorithms, programming, verification, and visualization. The pedagogical strategy is to use one case study – an ordinary differential equation describing exponential decay processes – to illustrate fundamental concepts in mathematics and computer science. The book is easy to read and only requires a command of one-variable calculus and some very basic knowledge about computer programming. Contrary to similar texts on numerical methods and programming, this text has a much stronger focus on implementation and teaches testing and software engineering in particular. .

  7. Exponential operators, generalized polynomials and evolution problems

    International Nuclear Information System (INIS)

    Dattoli, G.; Mancho, A.M.; Quattromini, M.; Torre, A.

    2001-01-01

    The operator (d/dx) χ d/dx plays a central role in the theory of operational calculus. Its exponential form is crucial in problems relevant to solutions of Fokker-Planck and Schroedinger equations. We explore the formal properties of the evolution operators associated to (d/dx) χ d/dx, discuss its link to special forms of Laguerre polynomials and Laguerre-based functions. The obtained results are finally applied to specific problems concerning the solution of Fokker-Planck equations relevant to the beam lifetime in storage rings

  8. Return probability: Exponential versus Gaussian decay

    Energy Technology Data Exchange (ETDEWEB)

    Izrailev, F.M. [Instituto de Fisica, BUAP, Apdo. Postal J-48, 72570 Puebla (Mexico)]. E-mail: izrailev@sirio.ifuap.buap.mx; Castaneda-Mendoza, A. [Instituto de Fisica, BUAP, Apdo. Postal J-48, 72570 Puebla (Mexico)

    2006-02-13

    We analyze, both analytically and numerically, the time-dependence of the return probability in closed systems of interacting particles. Main attention is paid to the interplay between two regimes, one of which is characterized by the Gaussian decay of the return probability, and another one is the well-known regime of the exponential decay. Our analytical estimates are confirmed by the numerical data obtained for two models with random interaction. In view of these results, we also briefly discuss the dynamical model which was recently proposed for the implementation of a quantum computation.

  9. Compact vs. Exponential-Size LP Relaxations

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.D.; Lancia, G.

    2000-09-01

    In this paper we introduce by means of examples a new technique for formulating compact (i.e. polynomial-size) LP relaxations in place of exponential-size models requiring separation algorithms. In the same vein as a celebrated theorem by Groetschel, Lovasz and Schrijver, we state the equivalence of compact separation and compact optimization. Among the examples used to illustrate our technique, we introduce a new formulation for the Traveling Salesman Problem, whose relaxation we show equivalent to the subtour elimination relaxation.

  10. How Entrustment Is Informed by Holistic Judgments Across Time in a Family Medicine Residency Program: An Ethnographic Nonparticipant Observational Study.

    Science.gov (United States)

    Sagasser, Margaretha H; Fluit, Cornelia R M G; van Weel, Chris; van der Vleuten, Cees P M; Kramer, Anneke W M

    2017-06-01

    Entrustment has mainly been conceptualized as delegating discrete professional tasks. Because residents provide most of their patient care independently, not all resident performance is visible to supervisors; the entrustment process involves more than granting discrete tasks. This study explored how supervisors made entrustment decisions based on residents' performance in a long-term family medicine training program. A qualitative nonparticipant observational study was conducted in 2014-2015 at competency-based family medicine residency programs in the Netherlands. Seven supervisor-resident pairs participated. During two days, one researcher observed first-year residents' patient encounters, debriefing sessions, and supervisor-resident educational meetings and interviewed them separately afterwards. Data were collected and analyzed using iterative, phenomenological inductive research methodology. The entrustment process developed over three phases. Supervisors based their initial entrustment on prior knowledge about the resident. In the ensuing two weeks, entrustment decisions regarding independent patient care were derived from residents' observed general competencies necessary for a range of health problems (clinical reasoning, decision making, relating to patients); medical knowledge and skills; and supervisors' intuition. Supervisors provided supervision during and after encounters. Once residents performed independently, supervisors kept reevaluating their decisions, informed by residents' overall growth in competencies rather than by adhering to a predefined set of tasks. Supervisors in family medicine residency training took a holistic approach to trust, based on general competencies, knowledge, skills, and intuition. Entrustment started before training and developed over time. Building trust is a mutual process between supervisor and resident, requiring a good working relationship.

  11. DNA Damage Observed in Unaffected Individuals with Family History of T2DM

    Science.gov (United States)

    Ramesh, Nikhila; Abilash, V. G.

    2017-11-01

    Diabetes has been documented to cause high levels of DNA fragmentation in some cases. As diabetes is inheritable and influenced by both genetic and environmental factors, an investigation into the genomic stability of individuals who are strongly at risk of inheriting diabetes was conducted by inducing oxidative stress, as DNA damage in unaffected individuals could be a sign of onset of the disease or the presence of genetic alterations that reduce cellular defences against reactive oxygen species. In this study, alkaline comet assay was performed on isolated human leukocytes to determine whether individuals with a family history of Type 2 Diabetes Mellitus (T2DM) are more prone to DNA damage under oxidative stress. Visual scoring of comets showed that these individuals have higher degree of DNA damage compared to a control individual with no family history of Type 2 Diabetes Mellitus. Further studies with large sample could determine the presence of disabled cellular defences against oxidative stress in unaffected individuals and intervention with antioxidants could prevent or manage Type 2 Diabetes Mellitus and its complications.

  12. Intergenerational Transmission of Familial Boundary Dissolution: Observations and Psychosocial Outcomes in Adolescence

    Science.gov (United States)

    Shaffer, Anne; Egeland, Byron

    2011-01-01

    This study investigated the transmission of boundary dissolution (BD) in parent-child relationships from parental behaviors observed in early childhood to adolescent behaviors observed at age 13 and relations to adolescent psychosocial adaptation. The goals of the study are (a) to examine the developmental relation of early childhood BD to several…

  13. Exponential frequency spectrum and Lorentzian pulses in magnetized plasmas

    International Nuclear Information System (INIS)

    Pace, D. C.; Shi, M.; Maggs, J. E.; Morales, G. J.; Carter, T. A.

    2008-01-01

    Two different experiments involving pressure gradients across the confinement magnetic field in a large plasma column are found to exhibit a broadband turbulence that displays an exponential frequency spectrum for frequencies below the ion cyclotron frequency. The exponential feature has been traced to the presence of solitary pulses having a Lorentzian temporal signature. These pulses arise from nonlinear interactions of drift-Alfven waves driven by the pressure gradients. In both experiments the width of the pulses is narrowly distributed resulting in exponential spectra with a single characteristic time scale. The temporal width of the pulses is measured to be a fraction of a period of the drift-Alfven waves. The experiments are performed in the Large Plasma Device (LAPD-U) [W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] operated by the Basic Plasma Science Facility at the University of California, Los Angeles. One experiment involves a controlled, pure electron temperature gradient associated with a microscopic (6 mm gradient length) hot electron temperature filament created by the injection a small electron beam embedded in the center of a large, cold magnetized plasma. The other experiment is a macroscopic (3.5 cm gradient length) limiter-edge experiment in which a density gradient is established by inserting a metallic plate at the edge of the nominal plasma column of the LAPD-U. The temperature filament experiment permits a detailed study of the transition from coherent to turbulent behavior and the concomitant change from classical to anomalous transport. In the limiter experiment the turbulence sampled is always fully developed. The similarity of the results in the two experiments strongly suggests a universal feature of pressure-gradient driven turbulence in magnetized plasmas that results in nondiffusive cross-field transport. This may explain previous observations in helical confinement devices, research tokamaks, and arc plasmas.

  14. Exponential decay and exponential recovery of modal gains in high count rate channel electron multipliers

    International Nuclear Information System (INIS)

    Hahn, S.F.; Burch, J.L.

    1980-01-01

    A series of data on high count rate channel electron multipliers revealed an initial drop and subsequent recovery of gains in exponential fashion. The FWHM of the pulse height distribution at the initial stage of testing can be used as a good criterion for the selection of operating bias voltage of the channel electron multiplier

  15. Dermatologic care in the homeless and underserved populations: observations from the Venice Family Clinic.

    Science.gov (United States)

    Grossberg, Anna L; Carranza, Dafnis; Lamp, Karen; Chiu, Melvin W; Lee, Catherine; Craft, Noah

    2012-01-01

    Dermatologic care in the homeless and impoverished urban underserved populations is rarely described despite the wide prevalence of skin concerns in this population. Because the homeless population may be subject to increased sun exposure compared to the nonhomeless population, they also may be at increased risk for skin cancer. We sought to describe the spectrum of dermatologic diseases seen in a free clinic in Venice, California--the Venice Family Clinic (VFC)--as well as the differences in diagnoses between the homeless and nonhomeless patients seen at this clinic. A retrospective chart review was performed of dermatology patients (N = 82) seen at VFC throughout the 2006 calendar year. The homeless population (n = 22) was found to have more diagnoses of malignant/premalignant growths (25% [16/64] of all homeless diagnoses) compared to their nonhomeless (n = 60) counterparts (6.1% [8/132] of all nonhomeless diagnoses; P < .0001). This difference was sustained when ethnicity was controlled, with 29.6% [16/54] of diagnoses in the homeless white group consisting of malignant/ premalignant growths compared to 8.9% [4/45] of diagnoses in the nonhomeless white cohort (P < .005). Homeless patients may have a higher incidence of skin cancers and precancerous skin lesions due to increased sun exposure and/or limited access to dermatologic care.

  16. Emotional climate and feeding styles: observational analysis of dinner in low-income families

    Science.gov (United States)

    Indulgent feeding styles have been associated with a higher risk for childhood overweight. The processes through which feeding styles impact child weight are poorly understood. The aim of this study was to observe differences in the emotional climate created by parents (affect, tone of voice, gest...

  17. On exponential stabilizability of linear neutral systems

    Directory of Open Access Journals (Sweden)

    Dusser Xavier

    2001-01-01

    Full Text Available In this paper, we deal with linear neutral functional differential systems. Using an extended state space and an extended control operator, we transform the initial neutral system in an infinite dimensional linear system. We give a sufficient condition for admissibility of the control operator B , conditions under which operator B can be acceptable in order to work with controllability and stabilizability. Necessary and sufficient conditions for exact controllability are provided; in terms of a gramian of controllability N ( μ . Assuming admissibility and exact controllability, a feedback control law is defined from the inverse of the operator N ( μ in order to stabilize exponentially the closed loop system. In this case, the semigroup generated by the closed loop system has an arbitrary decay rate.

  18. An exponentiation method for XML element retrieval.

    Science.gov (United States)

    Wichaiwong, Tanakorn

    2014-01-01

    XML document is now widely used for modelling and storing structured documents. The structure is very rich and carries important information about contents and their relationships, for example, e-Commerce. XML data-centric collections require query terms allowing users to specify constraints on the document structure; mapping structure queries and assigning the weight are significant for the set of possibly relevant documents with respect to structural conditions. In this paper, we present an extension to the MEXIR search system that supports the combination of structural and content queries in the form of content-and-structure queries, which we call the Exponentiation function. It has been shown the structural information improve the effectiveness of the search system up to 52.60% over the baseline BM25 at MAP.

  19. Poissonian renormalizations, exponentials, and power laws.

    Science.gov (United States)

    Eliazar, Iddo

    2013-05-01

    This paper presents a comprehensive "renormalization study" of Poisson processes governed by exponential and power-law intensities. These Poisson processes are of fundamental importance, as they constitute the very bedrock of the universal extreme-value laws of Gumbel, Fréchet, and Weibull. Applying the method of Poissonian renormalization we analyze the emergence of these Poisson processes, unveil their intrinsic dynamical structures, determine their domains of attraction, and characterize their structural phase transitions. These structural phase transitions are shown to be governed by uniform and harmonic intensities, to have universal domains of attraction, to uniquely display intrinsic invariance, and to be intimately connected to "white noise" and to "1/f noise." Thus, we establish a Poissonian explanation to the omnipresence of white and 1/f noises.

  20. Multiple Exponential Recombination for Differential Evolution.

    Science.gov (United States)

    Xin Qiu; Kay Chen Tan; Jian-Xin Xu

    2017-04-01

    Differential evolution (DE) is a popular population-based metaheuristic approach for solving numerical optimization problems. In recent years, considerable research has been devoted to the development of new mutation strategies and parameter adaptation mechanisms. However, as one of the basic algorithmic components of DE, the crossover operation has not been sufficiently examined in existing works. Most of the main DE variants solely employ traditional binomial recombination, which has intrinsic limitations in handling dependent subsets of variables. To fill this research niche, we propose a multiple exponential recombination that inherits all the main advantages of existing crossover operators while possessing a stronger ability in managing dependent variables. Multiple segments of the involved solutions will be exchanged during the proposed operator. The properties of the new scheme are examined both theoretically and empirically. Experimental results demonstrate the robustness of the proposed operator in solving problems with unknown variable interrelations.

  1. Statistics on exponential averaging of periodograms

    International Nuclear Information System (INIS)

    Peeters, T.T.J.M.; Ciftcioglu, Oe.

    1994-11-01

    The algorithm of exponential averaging applied to subsequent periodograms of a stochastic process is used to estimate the power spectral density (PSD). For an independent process, assuming the periodogram estimates to be distributed according to a χ 2 distribution with 2 degrees of freedom, the probability density function (PDF) of the PSD estimate is derived. A closed expression is obtained for the moments of the distribution. Surprisingly, the proof of this expression features some new insights into the partitions and Eulers infinite product. For large values of the time constant of the averaging process, examination of the cumulant generating function shows that the PDF approximates the Gaussian distribution. Although restrictions for the statistics are seemingly tight, simulation of a real process indicates a wider applicability of the theory. (orig.)

  2. Poissonian renormalizations, exponentials, and power laws

    Science.gov (United States)

    Eliazar, Iddo

    2013-05-01

    This paper presents a comprehensive “renormalization study” of Poisson processes governed by exponential and power-law intensities. These Poisson processes are of fundamental importance, as they constitute the very bedrock of the universal extreme-value laws of Gumbel, Fréchet, and Weibull. Applying the method of Poissonian renormalization we analyze the emergence of these Poisson processes, unveil their intrinsic dynamical structures, determine their domains of attraction, and characterize their structural phase transitions. These structural phase transitions are shown to be governed by uniform and harmonic intensities, to have universal domains of attraction, to uniquely display intrinsic invariance, and to be intimately connected to “white noise” and to “1/f noise.” Thus, we establish a Poissonian explanation to the omnipresence of white and 1/f noises.

  3. Evaluating GPS Station Trajectory Models for Postseismic Transient Deformation: Logarithmic Versus Exponential Forms

    Science.gov (United States)

    Sobrero, F. S.; Bevis, M. G.; Bedford, J. R.; Gomez, D.; Brown, A.; Wang, F.

    2017-12-01

    Simple or multiple timescale transient models for postseismic transient displacements can be formulated using logarithmic and exponential decay formulas. The logarithmic form is associated with rate and state friction theory and afterslip, while the exponential form is associated with bulk viscoelastic relaxation of coseismic stresses. Many theorists have suggested that afterslip will be the dominant driver of postseismic displacement transients in the months and perhaps even years following an earthquake, but viscoelastic relaxation will eventually dominate. It is now quite widely understood that one can model GPS time series manifesting postseismic transient displacements almost equally well using trajectory models constructed using logarithmic or exponential transients. This is consistent with the consensus established by the late 1970's that it is difficult to use geodetic observations to distinguish between deep aseismic afterslip and more diffuse viscoelastic relaxation as the primary mechanism of postseismic deformation. We assess the relative explanatory value of both logarithmic and exponential forms by focusing on GPS time series measured with better than typical signal-to-noise ratios. We find that the logarithmic transient typically provides slightly better fits than exponential transients, when both models are given equal degrees of freedom. We will also discuss the relative utility of the hybrid transient formulas in which the logarithmic component is assigned shorter decay time scale parameters than the exponential component.

  4. Stretched exponential relaxation processes in hydrogenated amorphous and polymorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Morigaki, Kazuo [Department of Electrical and Digital-System Engineering, Hiroshima Institute of Technology, Miyake, Saeki-ku, Hiroshima 731-5193 (Japan); Hikita, Harumi [Physics Laboratory, Meikai University, Urayasu, Chiba 279-8550 (Japan)

    2011-09-15

    Stretched exponential relaxation has been observed in various phenomena of hydrogenated amorphous silicon (a-Si:H) and hydrogenated polymorphous silicon (pm-Si:H). As an example, we take light-induced defect creation in a-Si:H and pm-Si:H, in which defect-creation process and defect-annihilation process via hydrogen movement play important roles. We have performed the Monte Carlo simulation for hydrogen movement. Hydrogen movement exhibits anomalous diffusion. In our model of light-induced defect creation in a-Si:H, a pair of two types of dangling bonds, i.e., a normal dangling bond and a hydrogen-related dangling bond, that is a dangling bond having hydrogen in the nearby site, are created under illumination, and hydrogen dissociated from the hydrogen-related dangling bond terminates a normal dangling bond via hydrogen movement. The amorphous network reflects on the dispersive parameter of the stretched exponential function in the light-induced defect creation. We discuss this issue, taking into account the difference in the amorphous network between a-Si:H and pm-Si:H (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Flow of viscous fluid along an exponentially stretching curved surface

    Directory of Open Access Journals (Sweden)

    N.F. Okechi

    Full Text Available In this paper, we present the boundary layer analysis of flow induced by rapidly stretching curved surface with exponential velocity. The governing boundary value problem is reduced into self-similar form using a new similarity transformation. The resulting equations are solved numerically using shooting and Runge-Kutta methods. The numerical results depicts that the fluid velocity as well as the skin friction coefficient increases with the surface curvature, similar trend is also observed for the pressure. The dimensionless wall shear stress defined for this problem is greater than that of a linearly stretching curved surface, but becomes comparably less for a surface stretching with a power-law velocity. In addition, the result for the plane surface is a special case of this study when the radius of curvature of the surface is sufficiently large. The numerical investigations presented in terms of the graphs are interpreted with the help of underlying physics of the fluid flow and the consequences arising from the curved geometry. Keywords: Boundary layer flow, Curved surface, Exponential stretching, Curvature

  6. Observance of the laws of family purity in modern-orthodox Judaism.

    Science.gov (United States)

    Guterman, Mark A

    2008-04-01

    This research is a follow-up to a previous study measuring the observance of the ritually unclean period (Niddah) among Modern-Orthodox Jews. A total of 267 participants completed an online questionnaire comprised of a list of 16 "strict" and "lenient" forbidden behaviors. Participants reported whether they had engaged in these behaviors during Week 1 (the actual menstrual period) and during Week 2 (the "clean days" following the cessation of bleeding). Results showed that laws were being violated, with more transgressions during the second week than the first week. Additionally, more "lenient" laws were being broken than "strict" ones. Level of religious observance was significantly negatively correlated to the number of transgressions. However, there was no significant correlation between the number of transgressions and the age at marriage, sex, or how long one had been married.

  7. The role of MEFV mutations in the concurrent disorders observed in patients with familial Mediterranean fever

    Science.gov (United States)

    Güncan, Sabri; Bilge, N. Şule Y.; Cansu, Döndü Üsküdar; Kaşifoğlu, Timuçin; Korkmaz, Cengiz

    2016-01-01

    Objective This study aimed to investigate the frequency in which familial Mediterranean fever (FMF) coexists with other diseases and determine whether Mediterranean fever (MEFV) gene mutations are involved in such coexistence. Material and Methods In total, 142 consecutive patients with FMF investigated for MEFV mutation were enrolled in this study [Female: 87; Male: 55, mean age 32±12 years (11–62)]. All the patients were questioned for the presence of concurrent disorders, and the medical records of these patients were revised retrospectively. A previous diagnosis of inflammatory disorder other than FMF was considered true if it met the relevant criteria. MEFV mutations were divided into 2 groups, namely M694V and its subgroup (homozygous or heterozygous) (Group I) and others (Group II). Compound heterozygosity for M694V mutation was included in Group II to form a homogeneous group for Group I. Group I and Group II were compared according to phenotypical features. The presence of MEFV mutation was investigated in exons 2, 3, 5, and 10 by the multiplex-PCR reverse hybridization method. Results Concomitant disorders were found in 17 of 73 patients with FMF (23%) in Group I and 5 of 56 patients (8.9%) in Group II (p=0.04). Concomitant disorders in Group I were as follows: 7 cases of amyloidosis, 2 cases of Behcet’s disease (BD), 4 cases of ankylosing spondylitis (AS), 1 case of antiphospholipid syndrome, 1 case of Henoch–Schonlein purpura (HSP), 1 case of combination of psoriatic arthritis, HSP, and membranoproliferative glomerulonephritis, and 1 case of AS and amyloidosis. In Group II, the following disorders were found: 1 case of amyloidosis, 1 case of BD, 1 case of AS, 1 case of ulcerative colitis, and 1 case of vitiligo. Conclusion The presence of M694V mutation may predispose patients with FMF to developing other inflammatory disorders. PMID:27733942

  8. Development of the General Parenting Observational Scale to assess parenting during family meals

    OpenAIRE

    Rhee, Kyung E; Dickstein, Susan; Jelalian, Elissa; Boutelle, Kerri; Seifer, Ronald; Wing, Rena

    2015-01-01

    © 2015 Rhee et al.; licensee BioMed Central. Background: There is growing interest in the relationship between general parenting and childhood obesity. However, assessing general parenting via surveys can be difficult due to issues with self-report and differences in the underlying constructs being measured. As a result, different aspects of parenting have been associated with obesity risk. We developed a more objective tool to assess general parenting by using observational methods during a ...

  9. The construction of power in family medicine bedside teaching: a video observation study.

    Science.gov (United States)

    Rees, Charlotte E; Ajjawi, Rola; Monrouxe, Lynn V

    2013-02-01

    Bedside teaching is essential for helping students develop skills, reasoning and professionalism, and involves the learning triad of student, patient and clinical teacher. Although current rhetoric espouses the sharing of power, the medical workplace is imbued with power asymmetries. Power is context-specific and although previous research has explored some elements of the enactment and resistance of power within bedside teaching, this exploration has been conducted within hospital rather than general practice settings. Furthermore, previous research has employed audio-recorded rather than video-recorded observation and has therefore focused on language and para-language at the expense of non-verbal communication and human-material interaction. A qualitative design was adopted employing video- and audio-recorded observations of seven bedside teaching encounters (BTEs), followed by short individual interviews with students, patients and clinical teachers. Thematic and discourse analyses of BTEs were conducted. Power is constructed by students, patients and clinical teachers throughout different BTE activities through the use of linguistic, para-linguistic and non-verbal communication. In terms of language, participants construct power through the use of questions, orders, advice, pronouns and medical/health belief talk. With reference to para-language, participants construct power through the use of interruption and laughter. In terms of non-verbal communication, participants construct power through physical positioning and the possession or control of medical materials such as the stethoscope. Using this paper as a trigger for discussion, we encourage students and clinical teachers to reflect critically on how their verbal and non-verbal communication constructs power in bedside teaching. Students and clinical teachers need to develop their awareness of what power is, how it can be constructed and shared, and what it means for the student

  10. Exponentiated exponential model (Gompertz kinetics) of Na+ and K+ conductance changes in squid giant axon.

    Science.gov (United States)

    Easton, D M

    1978-04-01

    The conductance changes, gK(t) and gNa(t), of squid giant axon under voltage clamp (Hodgkin and Huxley, 1952) may be modeled by exponentiated exponential functions (Gompertz kinetics) from any holding potential VO to any membrane clamp potential V. The equation constants are set by the membrane potential V, and include, for any voltage step in the case of gK, the initial conductance, gO, the asymptote conductance g, and rate constant k: gK = g exp(-be-kt) where b = 1n g/gO. Equations of similar form relate g and k to the voltage V, and govern the corresponding parameters of the gNa system. For the gNa, the fast phase y = y exp (-be-kt) is cut down in proportion to a slow process p = (1 - p)e-k't + p, and thus gNa = py. The expo-exponential functions involve fewer constants than the Hodgkin-Huxley model. In particular, the role of the n, m, h parameters appears to be filled largely by 1n (g/gO) in the case of gK and by 1n (y/yO) in the case of gNa. Membrane action potentials during current clamp may be computed from the conductances generated by use of the appropriate differential forms of the equations; diverse other membrane behaviors may be predicted.

  11. Exponential Stability of Stochastic Systems with Delay and Poisson Jumps

    Directory of Open Access Journals (Sweden)

    Wenli Zhu

    2014-01-01

    Full Text Available This paper focuses on the model of a class of nonlinear stochastic delay systems with Poisson jumps based on Lyapunov stability theory, stochastic analysis, and inequality technique. The existence and uniqueness of the adapted solution to such systems are proved by applying the fixed point theorem. By constructing a Lyapunov function and using Doob’s martingale inequality and Borel-Cantelli lemma, sufficient conditions are given to establish the exponential stability in the mean square of such systems, and we prove that the exponentially stable in the mean square of such systems implies the almost surely exponentially stable. The obtained results show that if stochastic systems is exponentially stable and the time delay is sufficiently small, then the corresponding stochastic delay systems with Poisson jumps will remain exponentially stable, and time delay upper limit is solved by using the obtained results when the system is exponentially stable, and they are more easily verified and applied in practice.

  12. Exponential Stability of Stochastic Differential Equation with Mixed Delay

    Directory of Open Access Journals (Sweden)

    Wenli Zhu

    2014-01-01

    Full Text Available This paper focuses on a class of stochastic differential equations with mixed delay based on Lyapunov stability theory, Itô formula, stochastic analysis, and inequality technique. A sufficient condition for existence and uniqueness of the adapted solution to such systems is established by employing fixed point theorem. Some sufficient conditions of exponential stability and corollaries for such systems are obtained by using Lyapunov function. By utilizing Doob’s martingale inequality and Borel-Cantelli lemma, it is shown that the exponentially stable in the mean square of such systems implies the almost surely exponentially stable. In particular, our theoretical results show that if stochastic differential equation is exponentially stable and the time delay is sufficiently small, then the corresponding stochastic differential equation with mixed delay will remain exponentially stable. Moreover, time delay upper limit is solved by using our theoretical results when the system is exponentially stable, and they are more easily verified and applied in practice.

  13. Exponential growth and atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Laurmann, J.A.; Rotty, R.M.

    1983-01-01

    The adequacy of assumptions required to project atmospheric CO 2 concentrations in time frames of practical importance is reviewed. Relevant issues concern the form assumed for future fossil fuel release, carbon cycle approximations, and the implications of revisions in fossil fuel patterns required to maintain atmospheric CO 2 levels below a chosen threshold. In general, we find that with a judiciously selected exponential fossil fuel release rate, and with a constant airborn fraction, we can estimate atmospheric CO 2 growth over the next 50 years based on essentially surprise free scenarios. Resource depletion effects must be included for projections beyond about 50 years, and on this time frame the constant airborne fraction approximation has to be questioned as well (especially in later years when the fossil fuel use begins to taper off). For projections for over 100 years, both energy demand scenarios and currently available carbon cycle models have sufficient uncertainties that atmospheric CO 2 levels derived from them are not much better than guesses

  14. An exponential decay model for mediation.

    Science.gov (United States)

    Fritz, Matthew S

    2014-10-01

    Mediation analysis is often used to investigate mechanisms of change in prevention research. Results finding mediation are strengthened when longitudinal data are used because of the need for temporal precedence. Current longitudinal mediation models have focused mainly on linear change, but many variables in prevention change nonlinearly across time. The most common solution to nonlinearity is to add a quadratic term to the linear model, but this can lead to the use of the quadratic function to explain all nonlinearity, regardless of theory and the characteristics of the variables in the model. The current study describes the problems that arise when quadratic functions are used to describe all nonlinearity and how the use of nonlinear functions, such as exponential decay, address many of these problems. In addition, nonlinear models provide several advantages over polynomial models including usefulness of parameters, parsimony, and generalizability. The effects of using nonlinear functions for mediation analysis are then discussed and a nonlinear growth curve model for mediation is presented. An empirical example using data from a randomized intervention study is then provided to illustrate the estimation and interpretation of the model. Implications, limitations, and future directions are also discussed.

  15. Exponential random graph models for networks with community structure.

    Science.gov (United States)

    Fronczak, Piotr; Fronczak, Agata; Bujok, Maksymilian

    2013-09-01

    Although the community structure organization is an important characteristic of real-world networks, most of the traditional network models fail to reproduce the feature. Therefore, the models are useless as benchmark graphs for testing community detection algorithms. They are also inadequate to predict various properties of real networks. With this paper we intend to fill the gap. We develop an exponential random graph approach to networks with community structure. To this end we mainly built upon the idea of blockmodels. We consider both the classical blockmodel and its degree-corrected counterpart and study many of their properties analytically. We show that in the degree-corrected blockmodel, node degrees display an interesting scaling property, which is reminiscent of what is observed in real-world fractal networks. A short description of Monte Carlo simulations of the models is also given in the hope of being useful to others working in the field.

  16. Fitting and Analyzing Randomly Censored Geometric Extreme Exponential Distribution

    Directory of Open Access Journals (Sweden)

    Muhammad Yameen Danish

    2016-06-01

    Full Text Available The paper presents the Bayesian analysis of two-parameter geometric extreme exponential distribution with randomly censored data. The continuous conjugate prior of the scale and shape parameters of the model does not exist while computing the Bayes estimates, it is assumed that the scale and shape parameters have independent gamma priors. It is seen that the closed-form expressions for the Bayes estimators are not possible; we suggest the Lindley’s approximation to obtain the Bayes estimates. However, the Bayesian credible intervals cannot be constructed while using this method, we propose Gibbs sampling to obtain the Bayes estimates and also to construct the Bayesian credible intervals. Monte Carlo simulation study is carried out to observe the behavior of the Bayes estimators and also to compare with the maximum likelihood estimators. One real data analysis is performed for illustration.

  17. Zero inflated negative binomial-generalized exponential distributionand its applications

    Directory of Open Access Journals (Sweden)

    Sirinapa Aryuyuen

    2014-08-01

    Full Text Available In this paper, we propose a new zero inflated distribution, namely, the zero inflated negative binomial-generalized exponential (ZINB-GE distribution. The new distribution is used for count data with extra zeros and is an alternative for data analysis with over-dispersed count data. Some characteristics of the distribution are given, such as mean, variance, skewness, and kurtosis. Parameter estimation of the ZINB-GE distribution uses maximum likelihood estimation (MLE method. Simulated and observed data are employed to examine this distribution. The results show that the MLE method seems to have high efficiency for large sample sizes. Moreover, the mean square error of parameter estimation is increased when the zero proportion is higher. For the real data sets, this new zero inflated distribution provides a better fit than the zero inflated Poisson and zero inflated negative binomial distributions.

  18. A nanostructured surface increases friction exponentially at the solid-gas interface

    Science.gov (United States)

    Phani, Arindam; Putkaradze, Vakhtang; Hawk, John E.; Prashanthi, Kovur; Thundat, Thomas

    2016-09-01

    According to Stokes’ law, a moving solid surface experiences viscous drag that is linearly related to its velocity and the viscosity of the medium. The viscous interactions result in dissipation that is known to scale as the square root of the kinematic viscosity times the density of the gas. We observed that when an oscillating surface is modified with nanostructures, the experimentally measured dissipation shows an exponential dependence on kinematic viscosity. The surface nanostructures alter solid-gas interplay greatly, amplifying the dissipation response exponentially for even minute variations in viscosity. Nanostructured resonator thus allows discrimination of otherwise narrow range of gaseous viscosity making dissipation an ideal parameter for analysis of a gaseous media. We attribute the observed exponential enhancement to the stochastic nature of interactions of many coupled nanostructures with the gas media.

  19. New multi-parametric analytical approximations of exponential distribution with power law tails for new cars sells and other applications

    Science.gov (United States)

    Garanina, O. S.; Romanovsky, M. Yu.

    2015-06-01

    A multi-parametric family of exponential distributions with various power law tails is introduced and is shown to describe adequately the known distributions of incomes and wealth as well as the recently measured distributions of new car sales. The three or four-parametric families are characterized by effective temperature in the exponential part, the power exponent in the power-law asymptotic part, the coefficient for the transition between the above two parts, and the starting value, if it is not equal to zero. Since the new car sales distributions are found to correspond to known distributions of incomes, the latter may be inferred from the former.

  20. Exponential stability of delayed fuzzy cellular neural networks with diffusion

    International Nuclear Information System (INIS)

    Huang Tingwen

    2007-01-01

    The exponential stability of delayed fuzzy cellular neural networks (FCNN) with diffusion is investigated. Exponential stability, significant for applications of neural networks, is obtained under conditions that are easily verified by a new approach. Earlier results on the exponential stability of FCNN with time-dependent delay, a special case of the model studied in this paper, are improved without using the time-varying term condition: dτ(t)/dt < μ

  1. Meet and join matrices in the poset of exponential divisors

    Indian Academy of Sciences (India)

    (n > 1), written as d |e n, if d(k) | n(k) for all prime divisors pk of n. It is easy to see that (Z+\\{1}, |e) is a poset under the exponential divisibility relation but not a lattice, since the greatest common exponential divisor (GCED) and the least common exponential multiple (LCEM) do not always exist. In this paper we embed this ...

  2. On global exponential stability of delayed cellular neural networks

    International Nuclear Information System (INIS)

    Singh, Vimal

    2007-01-01

    Senan and Arik [Senan S, Arik S. New results for exponential stability of delayed cellular neural networks. IEEE Trans Circ Syst II 2005;52(3):154-8] have presented criteria for the global exponential stability of delayed cellular neural networks. A less restrictive version of their approach is highlighted presently. A simplification of the results is discussed. A simplified form of an earlier exponential stability criterion due to Liao, Chen and Sanchez is presented

  3. An analytical approach to studying non-exponential decay

    Science.gov (United States)

    Petridis, Athanasios; Luban, Marshall; Vermedahl, Jon; Staunton, Lawrence

    2002-04-01

    Deviations from exponential decay have been numerically established for wavefunctions initially set inside potential wells of finite depth. The survival probability features oscillations about an initially non-exponential median curve. An analytical solution is developed for certain even-parity potentials to further understand this behavior. A connection between single-particle and multi-particle systems is investigated and shown to lead to the known exponential decay law for large systems.

  4. Fear of death, mortality communication, and psychological distress among secular and religiously observant family caregivers of terminal cancer patients.

    Science.gov (United States)

    Bachner, Yaacov G; O'Rourke, Norm; Carmel, Sara

    2011-02-01

    Previous research suggests that caregivers and terminally ill patients face substantial difficulties discussing illness and death. Existing research, however, has focused primarily on the experience of patients. The current study compared responses as well as the relative strength of association between mortality comunication, fear of death, and psychological distress (i.e., depressive symptomatology, emotional exhaustion) among secular and religiously observant family caregivers of terminally ill cancer patients. A total of 236 participants were recruited over 18 months within the first year of caregiver bereavement. Retrospectively reported mortality communication was statistically greater among secular caregivers; in contrast, both fear of death and depressive symptoms were greater among the religiously observant. Path analyses subsequently revealed notable differences between groups. Among secular caregivers, a significant inverse relationship between mortality communication and the two indices of caregiver distress emerged. In contrast, the association between mortality communication and psychological distress among the religious was moderated by these caregivers' fear of death. The results of this study suggest that fear of death is a significant predictor of psychological distress among religiously observant caregivers of terminal cancer patients (i.e., fear of their own death as elicited by the caregiving role). Fostering morality communication between secular caregivers and patients would appear to be one means of reducing the likelihood of clinically significant psychological distress. This may be insufficient among religiously observant caregivers, however, for whom fear of death may first need to be redressed.

  5. Theory for Transitions Between Exponential and Stationary Phases: Universal Laws for Lag Time

    Science.gov (United States)

    Himeoka, Yusuke; Kaneko, Kunihiko

    2017-04-01

    The quantitative characterization of bacterial growth has attracted substantial attention since Monod's pioneering study. Theoretical and experimental works have uncovered several laws for describing the exponential growth phase, in which the number of cells grows exponentially. However, microorganism growth also exhibits lag, stationary, and death phases under starvation conditions, in which cell growth is highly suppressed, for which quantitative laws or theories are markedly underdeveloped. In fact, the models commonly adopted for the exponential phase that consist of autocatalytic chemical components, including ribosomes, can only show exponential growth or decay in a population; thus, phases that halt growth are not realized. Here, we propose a simple, coarse-grained cell model that includes an extra class of macromolecular components in addition to the autocatalytic active components that facilitate cellular growth. These extra components form a complex with the active components to inhibit the catalytic process. Depending on the nutrient condition, the model exhibits typical transitions among the lag, exponential, stationary, and death phases. Furthermore, the lag time needed for growth recovery after starvation follows the square root of the starvation time and is inversely related to the maximal growth rate. This is in agreement with experimental observations, in which the length of time of cell starvation is memorized in the slow accumulation of molecules. Moreover, the lag time distributed among cells is skewed with a long time tail. If the starvation time is longer, an exponential tail appears, which is also consistent with experimental data. Our theory further predicts a strong dependence of lag time on the speed of substrate depletion, which can be tested experimentally. The present model and theoretical analysis provide universal growth laws beyond the exponential phase, offering insight into how cells halt growth without entering the death phase.

  6. INDISCRIMINATE BEHAVIOR OBSERVED IN THE STRANGE SITUATION AMONG INSTITUTIONALIZED TODDLERS: RELATIONS TO CAREGIVER REPORT AND TO EARLY FAMILY RISK.

    Science.gov (United States)

    Oliveira, Paula S; Soares, Isabel; Martins, Carla; Silva, Joana R; Marques, Sofia; Baptista, Joana; Lyons-Ruth, Karlen

    2012-03-01

    Socially disinhibited or indiscriminate behavior (IB) has traditionally been investigated using caregiver reports. More recently, an observational measure based on the Strange Situation Procedure (M. Ainsworth, M. Blehar, E. Waters, & S. Wall, 1978), the Rating of Infant and Stranger Engagement (RISE; C. Riley, A. Atlas-Corbett, & K. Lyons-Ruth, 2005), was validated in home-reared at-risk children. The present study aimed to validate the RISE in an institutionally reared sample using the caregiver report, to assess whether IB assessed with the RISE was elevated among the institutionalized children, and to explore potential risk factors associated with IB. The study was conducted among 74 institutionalized toddlers aged 11 to 30 months. Sociodemographic questionnaires were used to assess pre-admission experiences, and aspects of institutional placement were coded from the children's files in the institution and staff's report. Institutionalized children displayed high frequencies of IB as assessed on the RISE, and this instrument was validated against caregiver report. Pre-admission experiences of the institutionalized children in their biological families-namely, prenatal risk and maternal emotional neglect risk-predicted IB. Results suggest that the RISE is adequate to use among institutionally reared toddlers and point to aspects of the early familial environment that may be implicated in IB.

  7. Emotional climate, feeding practices, and feeding styles: an observational analysis of the dinner meal in Head Start families

    Directory of Open Access Journals (Sweden)

    Hall Sharon K

    2011-06-01

    Full Text Available Abstract Background A number of studies conducted with ethnically diverse, low-income samples have found that parents with indulgent feeding styles had children with a higher weight status. Indulgent parents are those who are responsive to their child's emotional states but have problems setting appropriate boundaries with their child. Because the processes through which styles impact child weight are poorly understood, the aim of this study was to observe differences in the emotional climate created by parents (including affect, tone of voice, and gestures and behavioral feeding practices among those reporting different feeding styles on the Caregiver's Feeding Styles Questionnaire. A secondary aim was to examine differences on child weight status across the feeding styles. Methods Participants were 177 Head Start families from Houston, Texas (45% African-American; 55% Hispanic. Using an observational approach, the relationship between the observed emotional climate of the meal, behavioral feeding practices, and self-reported parent feeding styles were examined. Mean age of the children was 4.4 years (SD = 0.7 equally distributed across gender. Families were observed on 3 separate dinner occasions. Heights and weight were measured on the parents and children. Results Parents with self-reported indulgent feeding styles made fewer demands on their children to eat during dinner and showed lower levels of negative affect and intrusiveness. Surprisingly, these parents also showed higher levels of emotional detachment with their children during dinner. Hispanic boys with indulgent parents had significantly higher BMI z scores compared to Hispanic boys in the other three feeding style groups. No other differences were found on child weight status. Conclusions Results suggest that the emotional climate created by indulgent parents during dinner and their lack of demands on their children to eat may play an important role in how young children become

  8. Emotional climate, feeding practices, and feeding styles: an observational analysis of the dinner meal in Head Start families.

    Science.gov (United States)

    Hughes, Sheryl O; Power, Thomas G; Papaioannou, Maria A; Cross, Matthew B; Nicklas, Theresa A; Hall, Sharon K; Shewchuk, Richard M

    2011-06-10

    A number of studies conducted with ethnically diverse, low-income samples have found that parents with indulgent feeding styles had children with a higher weight status. Indulgent parents are those who are responsive to their child's emotional states but have problems setting appropriate boundaries with their child. Because the processes through which styles impact child weight are poorly understood, the aim of this study was to observe differences in the emotional climate created by parents (including affect, tone of voice, and gestures) and behavioral feeding practices among those reporting different feeding styles on the Caregiver's Feeding Styles Questionnaire. A secondary aim was to examine differences on child weight status across the feeding styles. Participants were 177 Head Start families from Houston, Texas (45% African-American; 55% Hispanic). Using an observational approach, the relationship between the observed emotional climate of the meal, behavioral feeding practices, and self-reported parent feeding styles were examined. Mean age of the children was 4.4 years (SD = 0.7) equally distributed across gender. Families were observed on 3 separate dinner occasions. Heights and weight were measured on the parents and children. Parents with self-reported indulgent feeding styles made fewer demands on their children to eat during dinner and showed lower levels of negative affect and intrusiveness. Surprisingly, these parents also showed higher levels of emotional detachment with their children during dinner. Hispanic boys with indulgent parents had significantly higher BMI z scores compared to Hispanic boys in the other three feeding style groups. No other differences were found on child weight status. Results suggest that the emotional climate created by indulgent parents during dinner and their lack of demands on their children to eat may play an important role in how young children become overweight. Numerous observed emotional climate and behavioral

  9. Family-based behavioural intervention program for obese children: an observational study of child and parent lifestyle interpretations.

    Directory of Open Access Journals (Sweden)

    Marie Teder

    Full Text Available BACKGROUND: Family-based behavioural intervention programs (FBIPs against childhood obesity have shown promising results, but the mediating mechanisms have not been identified. The aim of this study was to examine changes in obese childreńs lifestyle habits during a 2-year FBIP according to their own and parents' reports, the concordance between these reports and the correlations to change in post-intervention z-BMI. METHODS: An observational study of 26 children (8.3-12.0 years and their parents participating in a 2-year FBIP was performed. Weight and height were measured from baseline to 12 months after the end of the program. Eating habits and physical- and sedentary activity were reported separately by children and parents. Data were analysed with regard to concordance between parents' and children's reports and association between the lifestyle reports and change in z-BMI at the study endpoint using descriptive statistics and parametric and non-parametric tests. RESULTS: According to both children's and parents' reports, the level of physical activity among the children had increased after the intervention as well as the agreement between the informants' reports. According to the children, eating habits had improved, while the parents' reports showed an improvement only with regard to binge eating. The concordance between children and parents regarding eating habits was slight to fair also after the intervention. No statistically significant associations between changes in lifestyle reports and changes in z-BMI were observed. CONCLUSIONS: Child and parent reports of physical activity were found to converge and display an improvement in a 2-year FBIP, while the reports on eating habits showed a more refractory pattern. Changes in concordance and agreement between children and parents reports did not correlate with weight reduction. Further methods development and studies of the processes during family-based interventions against childhood

  10. Experimental Verification of a Global Exponentially Stable Nonlinear Wave Encounter Frequency Estimator

    DEFF Research Database (Denmark)

    Belleter, Dennis J.W.; Galeazzi, Roberto; Fossen, Thor Inge

    2015-01-01

    This paper presents a global exponential stability (GES) proof for a signalbased nonlinear wave encounter frequency estimator. The estimator under consideration is a second-order nonlinear observer designed to estimate the frequency of a sinusoid with unknown frequency, amplitude and phase. The GES...... proof extends previous results that only guarantee global K-exponential stability. Typical applications are control and decision-support systems for marine craft, where it is important to know the sea state and wave frequency. The theoretical results are verified experimentally by analyzing data from...

  11. Fluid particles only separate exponentially in the dissipation range of turbulence after extremely long times

    Science.gov (United States)

    Dhariwal, Rohit; Bragg, Andrew D.

    2018-03-01

    In this paper, we consider how the statistical moments of the separation between two fluid particles grow with time when their separation lies in the dissipation range of turbulence. In this range, the fluid velocity field varies smoothly and the relative velocity of two fluid particles depends linearly upon their separation. While this may suggest that the rate at which fluid particles separate is exponential in time, this is not guaranteed because the strain rate governing their separation is a strongly fluctuating quantity in turbulence. Indeed, Afik and Steinberg [Nat. Commun. 8, 468 (2017), 10.1038/s41467-017-00389-8] argue that there is no convincing evidence that the moments of the separation between fluid particles grow exponentially with time in the dissipation range of turbulence. Motivated by this, we use direct numerical simulations (DNS) to compute the moments of particle separation over very long periods of time in a statistically stationary, isotropic turbulent flow to see if we ever observe evidence for exponential separation. Our results show that if the initial separation between the particles is infinitesimal, the moments of the particle separation first grow as power laws in time, but we then observe convincing evidence that at sufficiently long times the moments do grow exponentially. However, this exponential growth is only observed after extremely long times ≳200 τη , where τη is the Kolmogorov time scale. This is due to fluctuations in the strain rate about its mean value measured along the particle trajectories, the effect of which on the moments of the particle separation persists for very long times. We also consider the backward-in-time (BIT) moments of the article separation, and observe that they too grow exponentially in the long-time regime. However, a dramatic consequence of the exponential separation is that at long times the difference between the rate of the particle separation forward in time (FIT) and BIT grows

  12. shortened lag phase with seeds from early exponential phase

    African Journals Online (AJOL)

    AJL

    2012-01-12

    Jan 12, 2012 ... exponential or early stationary phase was selected as optimal. In the current study, the authors optimised inoculum conditions using a strategy that combined inoculum age and size as inoculum cell number to shorten the lag phase in yeast cultivation. Inoculum from the middle exponential phase (7th h).

  13. Ranking Exponential Trapezoidal Fuzzy Numbers by Median Value

    Directory of Open Access Journals (Sweden)

    S. Rezvani

    2013-12-01

    Full Text Available In this paper, we want represented a method for ranking of two exponential trapezoidal fuzzy numbers. A median value is proposed for the ranking of exponential trapezoidal fuzzy numbers. For the validation the results of the proposed approach are compared with different existing approaches.

  14. Exponential convergence on a continuous Monte Carlo transport problem

    International Nuclear Information System (INIS)

    Booth, T.E.

    1997-01-01

    For more than a decade, it has been known that exponential convergence on discrete transport problems was possible using adaptive Monte Carlo techniques. An adaptive Monte Carlo method that empirically produces exponential convergence on a simple continuous transport problem is described

  15. Stretched exponential relaxation and ac universality in disordered dielectrics

    DEFF Research Database (Denmark)

    Milovanov, Alexander V.; Rypdal, Kristoffer; Juul Rasmussen, Jens

    2007-01-01

    are stretched exponential character of dielectric relaxation, power-law power spectral density, and anomalous dependence of ac conduction coefficient on frequency. We propose a self-consistent model of dielectric relaxation in which the relaxations are described by a stretched exponential decay function...

  16. Global exponential stability for nonautonomous cellular neural networks with delays

    International Nuclear Information System (INIS)

    Zhang Qiang; Wei Xiaopeng; Xu Jin

    2006-01-01

    In this Letter, by utilizing Lyapunov functional method and Halanay inequalities, we analyze global exponential stability of nonautonomous cellular neural networks with delay. Several new sufficient conditions ensuring global exponential stability of the network are obtained. The results given here extend and improve the earlier publications. An example is given to demonstrate the effectiveness of the obtained results

  17. Stochastic B-series and order conditions for exponential integrators

    DEFF Research Database (Denmark)

    Arara, Alemayehu Adugna; Debrabant, Kristian; Kværnø, Anne

    2018-01-01

    We discuss stochastic differential equations with a stiff linear part and their approximation by stochastic exponential integrators. Representing the exact and approximate solutions using B-series and rooted trees, we derive the order conditions for stochastic exponential integrators. The resulting...

  18. Review of "Going Exponential: Growing the Charter School Sector's Best"

    Science.gov (United States)

    Garcia, David

    2011-01-01

    This Progressive Policy Institute report argues that charter schools should be expanded rapidly and exponentially. Citing exponential growth organizations, such as Starbucks and Apple, as well as the rapid growth of molds, viruses and cancers, the report advocates for similar growth models for charter schools. However, there is no explanation of…

  19. Stochastic B-series and order conditions for exponential integrators

    DEFF Research Database (Denmark)

    Arara, Alemayehu Adugna; Debrabant, Kristian; Kværnø, Anne

    2018-01-01

    We discuss stochastic differential equations with a stiff linear part and their approximation by stochastic exponential integrators. Representing the exact and approximate solutions using B-series and rooted trees, we derive the order conditions for stochastic exponential integrators. The resulti...... general order theory covers both It\\^{o} and Stratonovich integration....

  20. Non-exponential decay of wavefunctions and scattering resonances

    Science.gov (United States)

    Petridis, Athanasios; Vermedahl, Jonathan; Staunton, Lawrence; Luban, Marshall

    2001-10-01

    We investigate the possibility for non-exponential decay of wavefunctions initially distributed inside finite-range potential wells. The time dependence of the survival probability follows a step-wise pattern, deviating from a simple exponential function. The corresponding Breit-Winger curve for scattering resonances is modified due to this effect.

  1. Residual, restarting and Richardson iteration for the matrix exponential

    NARCIS (Netherlands)

    Bochev, Mikhail A.

    2010-01-01

    A well-known problem in computing some matrix functions iteratively is a lack of a clear, commonly accepted residual notion. An important matrix function for which this is the case is the matrix exponential. Assume, the matrix exponential of a given matrix times a given vector has to be computed. We

  2. Residual, restarting and Richardson iteration for the matrix exponential

    NARCIS (Netherlands)

    Bochev, Mikhail A.; Grimm, Volker; Hochbruck, Marlis

    2013-01-01

    A well-known problem in computing some matrix functions iteratively is the lack of a clear, commonly accepted residual notion. An important matrix function for which this is the case is the matrix exponential. Suppose the matrix exponential of a given matrix times a given vector has to be computed.

  3. Blowing-up semilinear wave equation with exponential nonlinearity ...

    Indian Academy of Sciences (India)

    H1-norm. Hence, it is legitimate to consider an exponential nonlinearity. Moreover, the choice of an exponential nonlinearity emerges from a possible control of solutions via a. Moser–Trudinger type inequality [1, 16, 19]. In fact, Nakamura and Ozawa [17] proved global well-posedness and scattering for small Cauchy data in ...

  4. New Results of Global Exponential Stabilization for BLDCMs System

    Directory of Open Access Journals (Sweden)

    Fengxia Tian

    2015-01-01

    Full Text Available The global exponential stabilization for brushless direct current motor (BLDCM system is studied. Four linear and simple feedback controllers are proposed to realize the global stabilization of BLDCM with exponential convergence rate; the control law used in each theorem is less conservative and more concise. Finally, an example is given to demonstrate the correctness of the proposed results.

  5. Rapid growth of seed black holes in the early universe by supra-exponential accretion.

    Science.gov (United States)

    Alexander, Tal; Natarajan, Priyamvada

    2014-09-12

    Mass accretion by black holes (BHs) is typically capped at the Eddington rate, when radiation's push balances gravity's pull. However, even exponential growth at the Eddington-limited e-folding time t(E) ~ few × 0.01 billion years is too slow to grow stellar-mass BH seeds into the supermassive luminous quasars that are observed when the universe is 1 billion years old. We propose a dynamical mechanism that can trigger supra-exponential accretion in the early universe, when a BH seed is bound in a star cluster fed by the ubiquitous dense cold gas flows. The high gas opacity traps the accretion radiation, while the low-mass BH's random motions suppress the formation of a slowly draining accretion disk. Supra-exponential growth can thus explain the puzzling emergence of supermassive BHs that power luminous quasars so soon after the Big Bang. Copyright © 2014, American Association for the Advancement of Science.

  6. Growth potential of exponential- and stationary-phase Salmonella Typhimurium during sausage fermentation

    DEFF Research Database (Denmark)

    Birk, Tina; Henriksen, Sidsel; Müller, K.

    2016-01-01

    Raw meat for sausage production can be contaminated with Salmonella. For technical reasons, meat is often frozen prior to mincing but it is unknown how growth of Salmonella in meat prior to freezing affects its growth potential during sausage fermentation. We investigated survival of exponential-...... fermentation, sporadic growth of exponential-phase cells of S. Typhimurium was observed drawing attention to the handling and storage of sausage meat.......Raw meat for sausage production can be contaminated with Salmonella. For technical reasons, meat is often frozen prior to mincing but it is unknown how growth of Salmonella in meat prior to freezing affects its growth potential during sausage fermentation. We investigated survival of exponential...... starter culture. With no starter culture, both strains grew in both growth phases. In general, a functional starter culture abolished S. Typhimurium growth independent of growth phase and we concluded that ensuring correct fermentation is important for sausage safety. However, despite efficient...

  7. Exponentiation of the Drell-Yan an cross section near partonic threshold in the DIS and MS-bar schemes

    International Nuclear Information System (INIS)

    Eynck, Tim Oliver; Laenen, Eric; Magnea, Lorenzo

    2003-01-01

    It has been observed that in the DIS scheme the refactorization of the Drell-Yan cross section leading to exponentiation of threshold logarithms can also be used to organize a class of constant terms, most of which arise from the ratio of the timelike Sudakov form factor to its spacelike counterpart. We extend this exponentiation to include all constant terms, and demonstrate how a similar organization may be achieved in the MS-bar scheme. We study the relevance of these exponentiations in a two-loop analysis. (author)

  8. Communication Quality Predicts Psychological Well-Being and Satisfaction in Family Surrogates of Hospitalized Older Adults: An Observational Study.

    Science.gov (United States)

    Torke, Alexia M; Callahan, Christopher M; Sachs, Greg A; Wocial, Lucia D; Helft, Paul R; Monahan, Patrick O; Slaven, James E; Montz, Kianna; Burke, Emily S; Inger, Lev

    2018-03-01

    Many hospitalized older adults require family surrogates to make decisions, but surrogates may perceive that the quality of medical decisions is low and may have poor psychological outcomes after the patient's hospitalization. To determine the relationship between communication quality and high-quality medical decisions, psychological well-being, and satisfaction for surrogates of hospitalized older adults. Observational study at three hospitals in a Midwest metropolitan area. Hospitalized older adults (65+ years) admitted to medicine and medical intensive care units who were unable to make medical decisions, and their family surrogates. Among 799 eligible dyads, 364 (45.6%) completed the study. Communication was assessed during hospitalization using the information and emotional support subscales of the Family Inpatient Communication Survey. Decision quality was assessed with the Decisional Conflict Scale. Outcomes assessed at baseline and 4-6 weeks post-discharge included anxiety (Generalized Anxiety Disorder-7), depression (Patient Health Questionnaire-9), post-traumatic stress (Impact of Event Scale-Revised), and satisfaction (Hospital Consumer Assessment of Healthcare Providers and Systems). The mean patient age was 81.9 years (SD 8.32); 62% were women, and 28% African American. Among surrogates, 67% were adult children. Six to eight weeks post-discharge, 22.6% of surrogates reported anxiety (11.3% moderate-severe anxiety); 29% reported depression, (14.0% moderate-severe), and 14.6% had high levels of post-traumatic stress. Emotional support was associated with lower odds of anxiety (adjusted odds ratio [AOR] = 0.65, 95% CI 0.50, 0.85) and depression (AOR = 0.80, 95% CI 0.65, 0.99) at follow-up. In multivariable linear regression, emotional support was associated with lower post-traumatic stress (β = -0.30, p = 0.003) and higher decision quality (β = -0.44, p Emotional support of hospital surrogates is consistently associated with better

  9. Extended q -Gaussian and q -exponential distributions from gamma random variables

    Science.gov (United States)

    Budini, Adrián A.

    2015-05-01

    The family of q -Gaussian and q -exponential probability densities fit the statistical behavior of diverse complex self-similar nonequilibrium systems. These distributions, independently of the underlying dynamics, can rigorously be obtained by maximizing Tsallis "nonextensive" entropy under appropriate constraints, as well as from superstatistical models. In this paper we provide an alternative and complementary scheme for deriving these objects. We show that q -Gaussian and q -exponential random variables can always be expressed as a function of two statistically independent gamma random variables with the same scale parameter. Their shape index determines the complexity q parameter. This result also allows us to define an extended family of asymmetric q -Gaussian and modified q -exponential densities, which reduce to the standard ones when the shape parameters are the same. Furthermore, we demonstrate that a simple change of variables always allows relating any of these distributions with a beta stochastic variable. The extended distributions are applied in the statistical description of different complex dynamics such as log-return signals in financial markets and motion of point defects in a fluid flow.

  10. Exponential fading to white of black holes in quantum gravity

    International Nuclear Information System (INIS)

    Barceló, Carlos; Carballo-Rubio, Raúl; Garay, Luis J

    2017-01-01

    Quantization of the gravitational field may allow the existence of a decay channel of black holes into white holes with an explicit time-reversal symmetry. The definition of a meaningful decay probability for this channel is studied in spherically symmetric situations. As a first nontrivial calculation, we present the functional integration over a set of geometries using a single-variable function to interpolate between black-hole and white-hole geometries in a bounded region of spacetime. This computation gives a finite result which depends only on the Schwarzschild mass and a parameter measuring the width of the interpolating region. The associated probability distribution displays an exponential decay law on the latter parameter, with a mean lifetime inversely proportional to the Schwarzschild mass. In physical terms this would imply that matter collapsing to a black hole from a finite radius bounces back elastically and instantaneously, with negligible time delay as measured by external observers. These results invite to reconsider the ultimate nature of astrophysical black holes, providing a possible mechanism for the formation of black stars instead of proper general relativistic black holes. The existence of both this decay channel and black stars can be tested in future observations of gravitational waves. (paper)

  11. (Anti)symmetric multivariate exponential functions and corresponding Fourier transforms

    International Nuclear Information System (INIS)

    Klimyk, A U; Patera, J

    2007-01-01

    We define and study symmetrized and antisymmetrized multivariate exponential functions. They are defined as determinants and antideterminants of matrices whose entries are exponential functions of one variable. These functions are eigenfunctions of the Laplace operator on the corresponding fundamental domains satisfying certain boundary conditions. To symmetric and antisymmetric multivariate exponential functions there correspond Fourier transforms. There are three types of such Fourier transforms: expansions into the corresponding Fourier series, integral Fourier transforms and multivariate finite Fourier transforms. Eigenfunctions of the integral Fourier transforms are found

  12. Analytic results for asymmetric random walk with exponential transition probabilities

    International Nuclear Information System (INIS)

    Gutkowicz-Krusin, D.; Procaccia, I.; Ross, J.

    1978-01-01

    We present here exact analytic results for a random walk on a one-dimensional lattice with asymmetric, exponentially distributed jump probabilities. We derive the generating functions of such a walk for a perfect lattice and for a lattice with absorbing boundaries. We obtain solutions for some interesting moment properties, such as mean first passage time, drift velocity, dispersion, and branching ratio for absorption. The symmetric exponential walk is solved as a special case. The scaling of the mean first passage time with the size of the system for the exponentially distributed walk is determined by the symmetry and is independent of the range

  13. Exponential Shear Flow of Linear, Entangled Polymeric Liquids

    DEFF Research Database (Denmark)

    Neergaard, Jesper; Park, Kyungho; Venerus, David C.

    2000-01-01

    A previously proposed reptation model is used to interpret exponential shear flow data taken on an entangled polystyrenesolution. Both shear and normal stress measurements are made during exponential shear using mechanical means. The model iscapable of explaining all trends seen in the data......, and suggests a novel analysis of the data. This analysis demonstrates thatexponential shearing flow is no more capable of stretching polymer chains than is inception of steady shear at comparableinstantaneous shear rates. In fact, all exponential shear flow stresses measured are bounded quantitatively...

  14. Periodic oscillation and exponential stability of delayed CNNs

    Science.gov (United States)

    Cao, Jinde

    2000-05-01

    Both the global exponential stability and the periodic oscillation of a class of delayed cellular neural networks (DCNNs) is further studied in this Letter. By applying some new analysis techniques and constructing suitable Lyapunov functionals, some simple and new sufficient conditions are given ensuring global exponential stability and the existence of periodic oscillatory solution of DCNNs. These conditions can be applied to design globally exponentially stable DCNNs and periodic oscillatory DCNNs and easily checked in practice by simple algebraic methods. These play an important role in the design and applications of DCNNs.

  15. Language Brokering in Latino Families: Direct Observations of Brokering Patterns, Parent-Child Interactions, and Relationship Quality

    OpenAIRE

    Straits, Kee J. E.

    2010-01-01

    With the growing percentage of immigrant families in the USA, language transition is a common immigrant experience and can occur rapidly from generation to generation within a family. Child language brokering appears to occur within minority language families as one way of negotiating language and cultural differences; however, the phenomenon of children translating or mediating language interactions for parents has previously been hypothesized to contribute to negative outcomes for children,...

  16. The temporal analysis of yeast exponential phase using shotgun proteomics as a fermentation monitoring technique.

    Science.gov (United States)

    Huang, Eric L; Orsat, Valérie; Shah, Manesh B; Hettich, Robert L; VerBerkmoes, Nathan C; Lefsrud, Mark G

    2012-09-18

    System biology and bioprocess technology can be better understood using shotgun proteomics as a monitoring system during the fermentation. We demonstrated a shotgun proteomic method to monitor the temporal yeast proteome in early, middle and late exponential phases. Our study identified a total of 1389 proteins combining all 2D-LC-MS/MS runs. The temporal Saccharomyces cerevisiae proteome was enriched with proteolysis, radical detoxification, translation, one-carbon metabolism, glycolysis and TCA cycle. Heat shock proteins and proteins associated with oxidative stress response were found throughout the exponential phase. The most abundant proteins observed were translation elongation factors, ribosomal proteins, chaperones and glycolytic enzymes. The high abundance of the H-protein of the glycine decarboxylase complex (Gcv3p) indicated the availability of glycine in the environment. We observed differentially expressed proteins and the induced proteins at mid-exponential phase were involved in ribosome biogenesis, mitochondria DNA binding/replication and transcriptional activator. Induction of tryptophan synthase (Trp5p) indicated the abundance of tryptophan during the fermentation. As fermentation progressed toward late exponential phase, a decrease in cell proliferation was implied from the repression of ribosomal proteins, transcription coactivators, methionine aminopeptidase and translation-associated proteins. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Global robust exponential stability analysis for interval recurrent neural networks

    International Nuclear Information System (INIS)

    Xu Shengyuan; Lam, James; Ho, Daniel W.C.; Zou Yun

    2004-01-01

    This Letter investigates the problem of robust global exponential stability analysis for interval recurrent neural networks (RNNs) via the linear matrix inequality (LMI) approach. The values of the time-invariant uncertain parameters are assumed to be bounded within given compact sets. An improved condition for the existence of a unique equilibrium point and its global exponential stability of RNNs with known parameters is proposed. Based on this, a sufficient condition for the global robust exponential stability for interval RNNs is obtained. Both of the conditions are expressed in terms of LMIs, which can be checked easily by various recently developed convex optimization algorithms. Examples are provided to demonstrate the reduced conservatism of the proposed exponential stability condition

  18. Re-analysis of exponential rigid-rotor astron equilibria

    International Nuclear Information System (INIS)

    Lovelace, R.V.; Larrabee, D.A.; Fleischmann, H.H.

    1978-01-01

    Previous studies of exponential rigid-rotor astron equilibria include particles which are not trapped in the self-field of the configuration. The modification of these studies required to exclude untrapped particles is derived

  19. Studying the method of linearization of exponential calibration curves

    International Nuclear Information System (INIS)

    Bunzh, Z.A.

    1989-01-01

    The results of study of the method for linearization of exponential calibration curves are given. The calibration technique and comparison of the proposed method with piecewise-linear approximation and power series expansion, are given

  20. Exponential Stability of Stochastic Nonlinear Dynamical Price System with Delay

    Directory of Open Access Journals (Sweden)

    Wenli Zhu

    2013-01-01

    Full Text Available Based on Lyapunov stability theory, Itô formula, stochastic analysis, and matrix theory, we study the exponential stability of the stochastic nonlinear dynamical price system. Using Taylor's theorem, the stochastic nonlinear system with delay is reduced to an n-dimensional semilinear stochastic differential equation with delay. Some sufficient conditions of exponential stability and corollaries for such price system are established by virtue of Lyapunov function. The time delay upper limit is solved by using our theoretical results when the system is exponentially stable. Our theoretical results show that if the classical price Rayleigh equation is exponentially stable, so is its perturbed system with delay provided that both the time delay and the intensity of perturbations are small enough. Two examples are presented to illustrate our results.

  1. The Multivariate Order Statistics for Exponential and Weibull Distributions

    Directory of Open Access Journals (Sweden)

    Mariyam Hafeez

    2014-09-01

    Full Text Available In this paper we have derived the distribution of multivariate order statistics for multivariate exponential & multivariate weibull distribution. The moment expression for multivariate order statistics has also been derived.

  2. Fast Modular Exponentiation and Elliptic Curve Group Operation in Maple

    Science.gov (United States)

    Yan, S. Y.; James, G.

    2006-01-01

    The modular exponentiation, y[equivalent to]x[superscript k](mod n) with x,y,k,n integers and n [greater than] 1; is the most fundamental operation in RSA and ElGamal public-key cryptographic systems. Thus the efficiency of RSA and ElGamal depends entirely on the efficiency of the modular exponentiation. The same situation arises also in elliptic…

  3. Testable Implications of Quasi-Hyperbolic and Exponential Time Discounting

    OpenAIRE

    Echenique, Federico; Imai, Taisuke; Saito, Kota

    2014-01-01

    We present the first revealed-preference characterizations of the models of exponential time discounting, quasi-hyperbolic time discounting, and other time-separable models of consumers’ intertemporal decisions. The characterizations provide non-parametric revealed-preference tests, which we take to data using the results of a recent experiment conducted by Andreoni and Sprenger (2012). For such data, we find that less than half the subjects are consistent with exponential discounting, and on...

  4. Meet and join matrices in the poset of exponential divisors

    Indian Academy of Sciences (India)

    ... exponential divisor ( G C E D ) and the least common exponential multiple ( L C E M ) do not always exist. In this paper we embed this poset in a lattice. As an application we study the G C E D and L C E M matrices, analogues of G C D and L C M matrices, which are both special cases of meet and join matrices on lattices.

  5. Global robust exponential stability for interval neural networks with delay

    International Nuclear Information System (INIS)

    Cui Shihua; Zhao Tao; Guo Jie

    2009-01-01

    In this paper, new sufficient conditions for globally robust exponential stability of neural networks with either constant delays or time-varying delays are given. We show the sufficient conditions for the existence, uniqueness and global robust exponential stability of the equilibrium point by employing Lyapunov stability theory and linear matrix inequality (LMI) technique. Numerical examples are given to show the approval of our results.

  6. Stretched exponential relaxation in molecular and electronic glasses

    International Nuclear Information System (INIS)

    Phillips, J.C.

    1996-01-01

    Stretched exponential relaxation, exp[-(t/τ) β ], fits many relaxation processes in disordered and quenched electronic and molecular systems, but it is widely believed that this function has no microscopic basis, especially in the case of molecular relaxation. For electronic relaxation the appearance of the stretched exponential is often described in the context of dispersive transport, where β is treated as an adjustable parameter, but in almost all cases it is generally assumed that no microscopic meaning can be assigned to 0 g , a glass transition temperature. We show that for molecular relaxation β(T g ) can be understood, providing that one separates extrinsic and intrinsic effects, and that the intrinsic effects are dominated by two magic numbers, β SR =3/5 for short-range forces, and β K =3/7 for long-range Coulomb forces, as originally observed by Kohlrausch for the decay of residual charge on a Leyden jar. Our mathematical model treats relaxation kinetics using the Lifshitz-Kac-Luttinger diffusion to traps depletion model in a configuration space of effective dimensionality, the latter being determined using axiomatic set theory and Phillips-Thorpe constraint theory. The experiments discussed include ns neutron scattering experiments, particularly those based on neutron spin echoes which measure S(Q, t) directly, and the traditional linear response measurements which span the range from μs to s, as collected and analysed phenomenologically by Angell, Ngai, Boehmer and others. The electronic materials discussed include a-Si:H, granular C 60 , semiconductor nanocrystallites, charge density waves in TaS 3 , spin glasses, and vortex glasses in high-temperature semiconductors. The molecular materials discussed include polymers, network glasses, electrolytes and alcohols, Van der Waals supercooled liquids and glasses, orientational glasses, water, fused salts, and heme proteins. In the intrinsic cases the theory of β(T g ) is often accurate to 2%, which

  7. Kinetically modified non-minimal inflation with exponential frame function

    Energy Technology Data Exchange (ETDEWEB)

    Pallis, C. [University of Cyprus, Department of Physics, Nicosia (Cyprus)

    2017-09-15

    We consider supersymmetric (SUSY) and non-SUSY models of chaotic inflation based on the φ{sup n} potential with n = 2 or 4. We show that the coexistence of an exponential non-minimal coupling to gravity f{sub R} = e{sup c{sub R}φ{sup p}} with a kinetic mixing of the form f{sub K} = c{sub K}f{sub R}{sup m} can accommodate inflationary observables favored by the Planck and Bicep2/Keck Array results for p = 1 and 2, 1 ≤ m ≤ 15 and 2.6 x 10{sup -3} ≤ r{sub RK} = c{sub R}/c{sub K}{sup p/2} ≤ 1, where the upper limit is not imposed for p = 1. Inflation is of hilltop type and it can be attained for subplanckian inflaton values with the corresponding effective theories retaining the perturbative unitarity up to the Planck scale. The supergravity embedding of these models is achieved employing two chiral gauge singlet supefields, a monomial superpotential and several (semi)logarithmic or semi-polynomial Kaehler potentials. (orig.)

  8. Scaling up paediatric HIV care with an integrated, family-centred approach: an observational case study from Uganda.

    Directory of Open Access Journals (Sweden)

    Emmanuel Luyirika

    Full Text Available Family-centred HIV care models have emerged as an approach to better target children and their caregivers for HIV testing and care, and further provide integrated health services for the family unit's range of care needs. While there is significant international interest in family-centred approaches, there is a dearth of research on operational experiences in implementation and scale-up. Our retrospective case study examined best practices and enabling factors during scale-up of family-centred care in ten health facilities and ten community clinics supported by a non-governmental organization, Mildmay, in Central Uganda. Methods included key informant interviews with programme management and families, and a desk review of hospital management information systems (HMIS uptake data. In the 84 months following the scale-up of the family-centred approach in HIV care, Mildmay experienced a 50-fold increase of family units registered in HIV care, a 40-fold increase of children enrolled in HIV care, and nearly universal coverage of paediatric cotrimoxazole prophylaxis. The Mildmay experience emphasizes the importance of streamlining care to maximize paediatric capture. This includes integrated service provision, incentivizing care-seeking as a family, creating child-friendly service environments, and minimizing missed paediatric testing opportunities by institutionalizing early infant diagnosis and provider-initiated testing and counselling. Task-shifting towards nurse-led clinics with community outreach support enabled rapid scale-up, as did an active management structure that allowed for real-time review and corrective action. The Mildmay experience suggests that family-centred approaches are operationally feasible, produce strong coverage outcomes, and can be well-managed during rapid scale-up.

  9. Contemporary Trends in the Management and Outcomes of Patients With Familial Hypercholesterolemia in Canada: A Prospective Observational Study.

    Science.gov (United States)

    Brunham, Liam R; Cermakova, Lubomira; Lee, Terry; Priecelova, Ida; Alloul, Karine; de Chantal, Marilyn; Francis, Gordon A; Frohlich, Jiri

    2017-03-01

    Heterozygous familial hypercholesterolemia (HeFH) is one of the most common genetic diseases in the world and an important cause of premature cardiovascular (CV) disease. The purpose of this study was to characterize the clinical features, current treatment patterns, and CV outcomes of patients with HeFH in British Columbia, Canada. We conducted a longitudinal observational study of patients with HeFH attending a specialized lipid clinic. We collected data on lipid levels, medication use, and CV events at baseline and last follow-up. We recruited 339 patients with clinically diagnosed HeFH, with a total of 3700 person-years of follow-up. The mean low-density lipoprotein cholesterol (LDL-C) level was 5.9 mmol/L at baseline and 3.7 mmol/L at last follow-up. Use of lipid-lowering therapy (LLT) increased from 35.7% at baseline to 84.7% at last follow-up. A ≥ 50% reduction in LDL-C level was achieved in 34.5% of patients, and an LDL-C level ≤ 2 mmol/L was seen in 8.3%. The overall CV event rate in this cohort was 33.5/1000 person-years. Among patients who had a CV event during follow-up, 59% experienced a recurrent event within 5 years. These data contribute to our understanding of contemporary trends in the management of patients with HeFH in Canada. Despite a majority of patients receiving LLT, few patients reached high-risk lipid targets. These data highlight important opportunities to improve the care of patients with HeFH. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Numerical study of MHD nanofluid flow and heat transfer past a bidirectional exponentially stretching sheet

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Rida [School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), Islamabad 44000 (Pakistan); Mustafa, M., E-mail: meraj_mm@hotmail.com [School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), Islamabad 44000 (Pakistan); Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Alsaedi, A. [Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia)

    2016-06-01

    Recent advancements in nanotechnology have led to the discovery of new generation coolants known as nanofluids. Nanofluids possess novel and unique characteristics which are fruitful in numerous cooling applications. Current work is undertaken to address the heat transfer in MHD three-dimensional flow of magnetic nanofluid (ferrofluid) over a bidirectional exponentially stretching sheet. The base fluid is considered as water which consists of magnetite–Fe{sub 3}O{sub 4} nanoparticles. Exponentially varying surface temperature distribution is accounted. Problem formulation is presented through the Maxwell models for effective electrical conductivity and effective thermal conductivity of nanofluid. Similarity transformations give rise to a coupled non-linear differential system which is solved numerically. Appreciable growth in the convective heat transfer coefficient is observed when nanoparticle volume fraction is augmented. Temperature exponent parameter serves to enhance the heat transfer from the surface. Moreover the skin friction coefficient is directly proportional to both magnetic field strength and nanoparticle volume fraction. - Highlights: • Nanofluid flow due to exponentially stretching sheet. • Exponentially varying surface temperature distribution is accounted. • Sparrow–Gregg type Hills (SGH) for temperature distribution exist. • Numerical values of local Nusselt number are presented. • Cooling performance of ferrofluid is superior to pure water.

  11. Numerical study of MHD nanofluid flow and heat transfer past a bidirectional exponentially stretching sheet

    International Nuclear Information System (INIS)

    Ahmad, Rida; Mustafa, M.; Hayat, T.; Alsaedi, A.

    2016-01-01

    Recent advancements in nanotechnology have led to the discovery of new generation coolants known as nanofluids. Nanofluids possess novel and unique characteristics which are fruitful in numerous cooling applications. Current work is undertaken to address the heat transfer in MHD three-dimensional flow of magnetic nanofluid (ferrofluid) over a bidirectional exponentially stretching sheet. The base fluid is considered as water which consists of magnetite–Fe 3 O 4 nanoparticles. Exponentially varying surface temperature distribution is accounted. Problem formulation is presented through the Maxwell models for effective electrical conductivity and effective thermal conductivity of nanofluid. Similarity transformations give rise to a coupled non-linear differential system which is solved numerically. Appreciable growth in the convective heat transfer coefficient is observed when nanoparticle volume fraction is augmented. Temperature exponent parameter serves to enhance the heat transfer from the surface. Moreover the skin friction coefficient is directly proportional to both magnetic field strength and nanoparticle volume fraction. - Highlights: • Nanofluid flow due to exponentially stretching sheet. • Exponentially varying surface temperature distribution is accounted. • Sparrow–Gregg type Hills (SGH) for temperature distribution exist. • Numerical values of local Nusselt number are presented. • Cooling performance of ferrofluid is superior to pure water.

  12. Exponential and Critical Experiments. Vol. III. Proceedings of the Symposium on Exponential and Critical Experiments

    International Nuclear Information System (INIS)

    1964-01-01

    In September 1963 the International Atomic Energy Agency organized the Symposium on Exponential and Critical Experiments in Amsterdam, Netherlands, at the invitation of the Government of the Netherlands. The Symposium enabled scientists from Member States to discuss the results of such experiments which provide the physics data necessary for the design of power reactors. Great advances made in recent years in this field have provided scientists with highly sophisticated and reliable experimental and theoretical methods. This trend is reflected in the presentation, at the Symposium, of many new experimental techniques resulting in more detailed and accurate information and a reduction of costs. Both the number of experimental parameters and their range of variation have been extended, and a closer degree of simulation of the actual power reactor has been achieved, for example, by means of high temperature critical assemblies. Basic types of lattices have continued to be the objective of many investigations, and extensive theoretical analyses have been carried out to provide a more thorough understanding of the neutron physics involved. Twenty nine countries and 3 international organizations were represented by 198 participants. Seventy one papers were presented. These numbers alone show the wide interest which the topic commands in the field of reactor design. We hope that this publication, which includes the papers presented at the Symposium and a record of the discussions, will prove useful as a work of reference to scientists working in this field

  13. Exponential growth combined with exponential decline explains lifetime performance evolution in individual and human species.

    Science.gov (United States)

    Berthelot, Geoffroy; Len, Stéphane; Hellard, Philippe; Tafflet, Muriel; Guillaume, Marion; Vollmer, Jean-Claude; Gager, Bruno; Quinquis, Laurent; Marc, Andy; Toussaint, Jean-François

    2012-08-01

    The physiological parameters characterizing human capacities (the ability to move, reproduce or perform tasks) evolve with ageing: performance is limited at birth, increases to a maximum and then decreases back to zero at the day of death. Physical and intellectual skills follow such a pattern. Here, we investigate the development of sport and chess performances during the lifetime at two different scales: the individual athletes' careers and the world record by age class in 25 Olympic sports events and in grandmaster chess players. For all data sets, a biphasic development of growth and decline is described by a simple model that accounts for 91.7% of the variance at the individual level and 98.5% of the variance at the species one. The age of performance peak is computed at 26.1 years old for the events studied (26.0 years old for track and field, 21.0 years old for swimming and 31.4 years old for chess). The two processes (growth and decline) are exponential and start at age zero. Both were previously demonstrated to happen in other human and non-human biological functions that evolve with age. They occur at the individual and species levels with a similar pattern, suggesting a scale invariance property.

  14. Children's Expressions of Positive Emotion Are Sustained by Smiling, Touching, and Playing with Parents and Siblings: A Naturalistic Observational Study of Family Life

    Science.gov (United States)

    Bai, Sunhye; Repetti, Rena L.; Sperling, Jacqueline B.

    2016-01-01

    Research on family socialization of positive emotion has primarily focused on the infant and toddler stages of development, and relied on observations of parent-child interactions in highly structured laboratory environments. Little is known about how children's spontaneous expressions of positive emotion are maintained in the uncontrolled…

  15. They never see how hard it is to be me: siblings' observations of strangers, peers and family.

    Science.gov (United States)

    Barr, Jacqueline; McLeod, Sharynne

    2010-04-01

    Siblings of children with disabilities are an important consideration for professionals working in family-centred contexts. Siblings of children with a disability often have unique experiences and insights that can assist understanding within family-centred interactions. In order to understand siblings' complex interactions with others in their lives, 676 contributions to a children's Internet sibling support site were analysed. Three themes arose from the inductive thematic analysis regarding siblings' interactions with strangers, peers, and their family. Identified subthemes (written from the perspective of the siblings) were as follows: Strangers stare and have negative attitudes towards my sibling with a disability; peers don't understand what it's like to be me, use certain words that upset me, say nasty things and tease me about my brother/sister; although my family loves me, they don't have a lot of time for me, our plans are often disrupted, and they give me a lot of responsibility. Within family-centred intervention it is recommended that health and education professionals, and parents assist siblings to build effective strategies for interacting with others others and learn from siblings' insights.

  16. Study on the Reflection Spectra of One Dimensional Plasma Photonic Crystals Having Exponentially Graded Materials

    International Nuclear Information System (INIS)

    Prasad, S.; Singh, Vivek; Singh, A. K.

    2013-01-01

    The transfer matrix method is used to study the effect of the permittivity profile on the reflectivity of a one dimensional plasma photonic crystal having exponentially graded material. The analysis shows that the proposed structure works as a perfect mirror within a certain frequency range. These frequency ranges can be completely controlled by the permittivity profile of a graded dielectric layer. As expected we observed that these frequency ranges are also controlled by plasma parameters. (plasma technology)

  17. Kullback-Leibler divergence and the Pareto-Exponential approximation.

    Science.gov (United States)

    Weinberg, G V

    2016-01-01

    Recent radar research interests in the Pareto distribution as a model for X-band maritime surveillance radar clutter returns have resulted in analysis of the asymptotic behaviour of this clutter model. In particular, it is of interest to understand when the Pareto distribution is well approximated by an Exponential distribution. The justification for this is that under the latter clutter model assumption, simpler radar detection schemes can be applied. An information theory approach is introduced to investigate the Pareto-Exponential approximation. By analysing the Kullback-Leibler divergence between the two distributions it is possible to not only assess when the approximation is valid, but to determine, for a given Pareto model, the optimal Exponential approximation.

  18. Exponential Sensitivity and its Cost in Quantum Physics.

    Science.gov (United States)

    Gilyén, András; Kiss, Tamás; Jex, Igor

    2016-02-10

    State selective protocols, like entanglement purification, lead to an essentially non-linear quantum evolution, unusual in naturally occurring quantum processes. Sensitivity to initial states in quantum systems, stemming from such non-linear dynamics, is a promising perspective for applications. Here we demonstrate that chaotic behaviour is a rather generic feature in state selective protocols: exponential sensitivity can exist for all initial states in an experimentally realisable optical scheme. Moreover, any complex rational polynomial map, including the example of the Mandelbrot set, can be directly realised. In state selective protocols, one needs an ensemble of initial states, the size of which decreases with each iteration. We prove that exponential sensitivity to initial states in any quantum system has to be related to downsizing the initial ensemble also exponentially. Our results show that magnifying initial differences of quantum states (a Schrödinger microscope) is possible; however, there is a strict bound on the number of copies needed.

  19. On the performance of exponential integrators for problems in magnetohydrodynamics

    Science.gov (United States)

    Einkemmer, Lukas; Tokman, Mayya; Loffeld, John

    2017-02-01

    Exponential integrators have been introduced as an efficient alternative to explicit and implicit methods for integrating large stiff systems of differential equations. Over the past decades these methods have been studied theoretically and their performance was evaluated using a range of test problems. While the results of these investigations showed that exponential integrators can provide significant computational savings, the research on validating this hypothesis for large scale systems and understanding what classes of problems can particularly benefit from the use of the new techniques is in its initial stages. Resistive magnetohydrodynamic (MHD) modeling is widely used in studying large scale behavior of laboratory and astrophysical plasmas. In many problems numerical solution of MHD equations is a challenging task due to the temporal stiffness of this system in the parameter regimes of interest. In this paper we evaluate the performance of exponential integrators on large MHD problems and compare them to a state-of-the-art implicit time integrator. Both the variable and constant time step exponential methods of EPIRK-type are used to simulate magnetic reconnection and the Kevin-Helmholtz instability in plasma. Performance of these methods, which are part of the EPIC software package, is compared to the variable time step variable order BDF scheme included in the CVODE (part of SUNDIALS) library. We study performance of the methods on parallel architectures and with respect to magnitudes of important parameters such as Reynolds, Lundquist, and Prandtl numbers. We find that the exponential integrators provide superior or equal performance in most circumstances and conclude that further development of exponential methods for MHD problems is warranted and can lead to significant computational advantages for large scale stiff systems of differential equations such as MHD.

  20. Contribution of mono-exponential, bi-exponential and stretched exponential model-based diffusion-weighted MR imaging in the diagnosis and differentiation of uterine cervical carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Meng; Yu, Xiaoduo; Chen, Yan; Ouyang, Han; Zhou, Chunwu [Chinese Academy of Medical Sciences, Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Beijing (China); Wu, Bing; Zheng, Dandan [GE MR Research China, Beijing (China)

    2017-06-15

    To investigate the potential of various metrics derived from mono-exponential model (MEM), bi-exponential model (BEM) and stretched exponential model (SEM)-based diffusion-weighted imaging (DWI) in diagnosing and differentiating the pathological subtypes and grades of uterine cervical carcinoma. 71 newly diagnosed patients with cervical carcinoma (50 cases of squamous cell carcinoma [SCC] and 21 cases of adenocarcinoma [AC]) and 32 healthy volunteers received DWI with multiple b values. The apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), water molecular diffusion heterogeneity index (alpha), and distributed diffusion coefficient (DDC) were calculated and compared between tumour and normal cervix, among different pathological subtypes and grades. All of the parameters were significantly lower in cervical carcinoma than normal cervical stroma except alpha. SCC showed lower ADC, D, f and DDC values and higher D* value than AC; D and DDC values of SCC and ADC and D values of AC were lower in the poorly differentiated group than those in the well-moderately differentiated group. Compared with MEM, diffusion parameters from BEM and SEM may offer additional information in cervical carcinoma diagnosis, predicting pathological tumour subtypes and grades, while f and D showed promising significance. (orig.)

  1. Lagrange α-exponential stability and α-exponential convergence for fractional-order complex-valued neural networks.

    Science.gov (United States)

    Jian, Jigui; Wan, Peng

    2017-07-01

    This paper deals with the problem on Lagrange α-exponential stability and α-exponential convergence for a class of fractional-order complex-valued neural networks. To this end, some new fractional-order differential inequalities are established, which improve and generalize previously known criteria. By using the new inequalities and coupling with the Lyapunov method, some effective criteria are derived to guarantee Lagrange α-exponential stability and α-exponential convergence of the addressed network. Moreover, the framework of the α-exponential convergence ball is also given, where the convergence rate is related to the parameters and the order of differential of the system. These results here, which the existence and uniqueness of the equilibrium points need not to be considered, generalize and improve the earlier publications and can be applied to monostable and multistable fractional-order complex-valued neural networks. Finally, one example with numerical simulations is given to show the effectiveness of the obtained results. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Minimizing the effect of exponential trends in detrended fluctuation analysis

    International Nuclear Information System (INIS)

    Xu Na; Shang Pengjian; Kamae, Santi

    2009-01-01

    The detrended fluctuation analysis (DFA) and its extensions (MF-DFA) have been used extensively to determine possible long-range correlations in time series. However, recent studies have reported the susceptibility of DFA to trends which give rise to spurious crossovers and prevent reliable estimation of the scaling exponents. In this report, a smoothing algorithm based on the discrete laplace transform (DFT) is proposed to minimize the effect of exponential trends and distortion in the log-log plots obtained by MF-DFA techniques. The effectiveness of the technique is demonstrated on monofractal and multifractal data corrupted with exponential trends.

  3. Fuel elements assembling for the DON project exponential experience

    International Nuclear Information System (INIS)

    Anca Abati, R. de

    1966-01-01

    It is described the fuel unit used in the DON exponential experience, the manufacturing installments and tools as well as the stages in the fabrication.These 74 elements contain each 19 cartridges loaded with synterized urania, uranium carbide and indium, gold, and manganese probes. They were arranged in calandria-like tubes and the process-tube. This last one containing a cooling liquid simulating the reactor organic. Besides being used in the DON reactor exponential experience they were used in critic essays by the substitution method in the French reactor AQUILON II. (Author) 6 refs

  4. Generator of an exponential function with respect to time

    International Nuclear Information System (INIS)

    Janin, Paul; Puyal, Claude.

    1981-01-01

    This invention deals with an exponential function generator, and an application of this generator to simulating the criticality of a nuclear reactor for reactimeter calibration purposes. This generator, which is particularly suitable for simulating the criticality of a nuclear reactor to calibrate a reactimeter, can also be used in any field of application necessitating the generation of an exponential function in real time. In certain fields of thermodynamics, it is necessary to represent temperature gradients as a function of time. The generator might find applications here. Another application is nuclear physics where it is necessary to represent the attenuation of a neutron flux density with respect to time [fr

  5. Exponential stability of neural networks with asymmetric connection weights

    International Nuclear Information System (INIS)

    Yang Jinxiang; Zhong Shouming

    2007-01-01

    This paper investigates the exponential stability of a class of neural networks with asymmetric connection weights. By dividing the network state variables into various parts according to the characters of the neural networks, some new sufficient conditions of exponential stability are derived via constructing a Lyapunov function and using the method of the variation of constant. The new conditions are associated with the initial values and are described by some blocks of the interconnection matrix, and do not depend on other blocks. Examples are given to further illustrate the theory

  6. Collisional avalanche exponentiation of runaway electrons in electrified plasmas

    International Nuclear Information System (INIS)

    Jayakumar, R.; Fleischmann, H.H.; Zweben, S.J.

    1993-01-01

    In contrast to earlier expectations, it is estimated that generation of runaway electrons from close collisions of existing runaways with cold plasma electrons can be significant even for small electric fields, whenever runaways can gain energies of about 20 MeV or more. In that case, the runaway population will grow exponentially with the energy spectrum showing an exponential decrease towards higher energies. Energy gains of the required magnitude may occur in large tokamak devices as well as in cosmic-ray generation. (orig.)

  7. Non-exponential dynamic relaxation in strongly nonequilibrium nonideal plasmas

    International Nuclear Information System (INIS)

    Morozov, I V; Norman, G E

    2003-01-01

    Relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics method for nonideal two-component non-degenerate plasmas. Three limiting examples of initial states of strongly nonequilibrium plasma are considered: zero electron velocities, zero ion velocities and zero velocities of both electrons and ions. The initial non-exponential stage, its duration τ nB and subsequent exponential stages of the relaxation process are studied for a wide range of the nonideality parameter and the ion mass

  8. pth Moment Exponential Stability of Nonlinear Hybrid Stochastic Heat Equations

    Directory of Open Access Journals (Sweden)

    Xuetao Yang

    2014-01-01

    Full Text Available We are concerned with the exponential stability problem of a class of nonlinear hybrid stochastic heat equations (known as stochastic heat equations with Markovian switching in an infinite state space. The fixed point theory is utilized to discuss the existence, uniqueness, and pth moment exponential stability of the mild solution. Moreover, we also acquire the Lyapunov exponents by combining the fixed point theory and the Gronwall inequality. At last, two examples are provided to verify the effectiveness of our obtained results.

  9. Numerical Studies of Non-Exponential Decay of Wavefunctions

    Science.gov (United States)

    Vermedahl, Jon; Petridis, Athanasios; Luban, Marshall; Staunton, Lawrence

    2002-04-01

    We use the staggered-leap-frog algorithm to numerically solve the time-dependent Schrödinger equation. This algorithm is particularly accurate and stable as demonstrated in a number of cases whose solutions are analytically known. Deviations from exponential decay have been established for short times for a wavefunction initially set within finite depth potential wells. The survival probability has been fit with analytical functions that reproduce exponential decay at long times. Various time scales characterizing the decay are thus extracted.

  10. Stability of the Exponential Functional Equation in Riesz Algebras

    Directory of Open Access Journals (Sweden)

    Bogdan Batko

    2014-01-01

    Full Text Available We deal with the stability of the exponential Cauchy functional equation F(x+y=F(xF(y in the class of functions F:G→L mapping a group (G, + into a Riesz algebra L. The main aim of this paper is to prove that the exponential Cauchy functional equation is stable in the sense of Hyers-Ulam and is not superstable in the sense of Baker. To prove the stability we use the Yosida Spectral Representation Theorem.

  11. Real-Time Exponential Curve Fits Using Discrete Calculus

    Science.gov (United States)

    Rowe, Geoffrey

    2010-01-01

    An improved solution for curve fitting data to an exponential equation (y = Ae(exp Bt) + C) has been developed. This improvement is in four areas -- speed, stability, determinant processing time, and the removal of limits. The solution presented avoids iterative techniques and their stability errors by using three mathematical ideas: discrete calculus, a special relationship (be tween exponential curves and the Mean Value Theorem for Derivatives), and a simple linear curve fit algorithm. This method can also be applied to fitting data to the general power law equation y = Ax(exp B) + C and the general geometric growth equation y = Ak(exp Bt) + C.

  12. Exponential Synchronization of Uncertain Complex Dynamical Networks with Delay Coupling

    International Nuclear Information System (INIS)

    Wang Lifu; Kong Zhi; Jing Yuanwei

    2010-01-01

    This paper studies the global exponential synchronization of uncertain complex delayed dynamical networks. The network model considered is general dynamical delay networks with unknown network structure and unknown coupling functions but bounded. Novel delay-dependent linear controllers are designed via the Lyapunov stability theory. Especially, it is shown that the controlled networks are globally exponentially synchronized with a given convergence rate. An example of typical dynamical network of this class, having the Lorenz system at each node, has been used to demonstrate and verify the novel design proposed. And, the numerical simulation results show the effectiveness of proposed synchronization approaches. (general)

  13. On exponential stability and periodic solutions of CNNs with delays

    Science.gov (United States)

    Cao, Jinde

    2000-03-01

    In this Letter, the author analyses further problems of global exponential stability and the existence of periodic solutions of cellular neural networks with delays (DCNNs). Some simple and new sufficient conditions are given ensuring global exponential stability and the existence of periodic solutions of DCNNs by applying some new analysis techniques and constructing suitable Lyapunov functionals. These conditions have important leading significance in the design and applications of globally stable DCNNs and periodic oscillatory DCNNs and are weaker than those in the earlier works [Phys. Rev. E 60 (1999) 3244], [J. Comput. Syst. Sci. 59 (1999)].

  14. Outcome of a Food Observational Study among Low-Income Preschool Children Participating in a Family-Style Meal Setting

    Science.gov (United States)

    Treviño, Roberto P.; Vasquez, Liset; Shaw-Ridley, Mary; Mosley, Desiree; Jechow, Katherine; Piña, Christina

    2015-01-01

    Introduction: In the United States, one out of every seven low-income children between the ages of 2 and 5 years is at risk for overweight and obesity. Formative research was conducted to determine if preschool children participating in family-style meals consumed the minimum food servings according to U.S. Department of Agriculture dietary…

  15. Correlation between patient quality of life in palliative care and burden of their family caregivers: a prospective observational cohort study.

    Science.gov (United States)

    Krug, Katja; Miksch, Antje; Peters-Klimm, Frank; Engeser, Peter; Szecsenyi, Joachim

    2016-01-15

    Family caregivers play a key role in palliative care at home, and understanding the interdependencies in the constellation of patient, family caregivers and service providers is important. As few longitudinal studies have examined the influence of patient quality of life (QoL) in palliative care on burden of family caregivers, the aim of this study was to identify correlations between changing patient QoL and changing burden of family caregivers that need consideration in patient management. Palliative patients with cancer in primary care evaluated their QoL (Quality of Life Questionnaire Core 15 Palliative Care, QLQ-C15-PAL). They were assessed monthly for an interval of 6 months or until death of the patient. Family caregivers reported the burden they perceived while supporting the patient (Short form of the Burden Scale for Family Caregivers, BSFC). Longitudinal data were analysed for all patients with at least 3 available assessments, considering the most recent data for participants with more than 3 assessments. Changes in patient QoL were analysed using the Friedman test. In a stepwise regression analysis, influences of change in patient QoL on changing caregiver burden were investigated. One hundred patients (63 men, 37 women; average age: 68 years) were enrolled in the study. The most common primary diagnoses were colon, lung or breast cancer. In 58 cases, assessments were available from both patients and caregivers. Patients reported overall quality of life increasing towards end of life, although reporting that physical functioning deteriorated. Symptoms of pain and fatigue bothered patients most. Caregiver burden was moderate and on average did not change over time. In a stepwise regression model, the difference in emotional functioning and the difference in dyspnoea showed an influence on the development of caregiver burden (explained variance of 19.3%). Patients' dyspnoea, feelings of depression and anxiety impacted on the perceived burden of family

  16. On exponential cosmological type solutions in the model with Gauss-Bonnet term and variation of gravitational constant

    International Nuclear Information System (INIS)

    Ivashchuk, V.D.; Kobtsev, A.A.

    2015-01-01

    A D-dimensional gravitational model with Gauss.Bonnet term is considered. When an ansatz with diagonal cosmological type metrics is adopted, we find solutions with an exponential dependence of the scale factors (with respect to a @gsynchronous-like@h variable) which describe an exponential expansion of @gour@h 3-dimensional factor space and obey the observational constraints on the temporal variation of effective gravitational constant G. Among them there are two exact solutions in dimensions D = 22, 28 with constant G and also an infinite series of solutions in dimensions D ≥ 2690 with the variation of G obeying the observational data. (orig.)

  17. Improvement of the exponential experiment system for the automatical and accurate measurement of the exponential decay constant

    International Nuclear Information System (INIS)

    Shin, Hee Sung; Jang, Ji Woon; Lee, Yoon Hee; Hwang, Yong Hwa; Kim, Ho Dong

    2004-01-01

    The previous exponential experiment system has been improved for the automatical and accurate axial movement of the neutron source and detector with attaching the automatical control system which consists of a Programmable Logical Controller(PLC) and a stepping motor set. The automatic control program which controls MCA and PLC consistently has been also developed on the basis of GENIE 2000 library. The exponential experiments have been carried out for Kori 1 unit spent fuel assemblies, C14, J14 and G23, and Kori 2 unit spent fuel assembly, J44, using the improved systematical measurement system. As the results, the average exponential decay constants for 4 assemblies are determined to be 0.1302, 0.1267, 0.1247, and 0.1210, respectively, with the application of poisson regression

  18. Pre-exponential factor in general order kinetics of thermoluminescence and its influence on glow curves

    International Nuclear Information System (INIS)

    Sunta, C.M.; Ayta, W.E.F.; Chen, R.; Watanabe, S.

    1997-01-01

    A model of thermoluminescence kinetics based on a physically meaningful approach shows that the glow curve shapes undergo systematic changes with the change of trap occupancy (dose). In terms of the general order kinetics model it means that the kinetic order changes with sample dose. In parallel to the kinetic order, the pre-exponential factor also changes. In contrast to these results the glow curves calculated from the general order kinetics model show that the peak shape remains nearly constant when the trap occupancy is changed. When appropriately defined, the pre-exponential factor also has a fixed value independent of trap occupancy. In these respects the general order kinetics model, though empirical, seems to describe the glow peak behaviour quite successfully. However, regarding the peak temperature the theoretical results both from the physical as well as the empirical model seem to diverge from the experimental observations when the experimentally determined kinetics is non-first order. (author)

  19. Effects of Exponential Nonlinear Electrodynamics and External Magnetic Field on Holographic Superconductors

    Science.gov (United States)

    Sheykhi, A.; Abdollahzadeh, Z.

    2018-03-01

    We investigate the effects of an external magnetic field as well as exponential nonlinear electrodynamics on the properties of s-wave holographic superconductors. Our strategy for this study is the matching method, which is based on the match of the solutions near the horizon and on the boundary at some intermediate point. When the magnetic field is turned off, we obtain the critical temperature as well as the condensation operator and show that the critical exponent is still 1/2, which is the universal value in the mean field theory. Then, we turn on the magnetic field and obtain the critical magnetic field, B c , in order to study its behavior in terms of the temperature. Interestingly enough, we find that in the presence of exponential nonlinear electrodynamics, the critical temperature decreases, while the critical magnetic field increases compared to the Maxwell case. We also observe that the critical magnetic field increases with increasing the nonlinear parameter b.

  20. Exponential dichotomy of nonautonomous periodic systems in terms of the boundedness of certain periodic Cauchy problems

    Directory of Open Access Journals (Sweden)

    Dhaou Lassoued

    2013-04-01

    Full Text Available We prove that a family of $q$-periodic continuous matrix valued function ${A(t}_{tin mathbb{R}}$ has an exponential dichotomy with a projector $P$ if and only if $int_0^t e^{imu s}U(t,sPds$ is bounded uniformly with respect to the parameter $mu$ and the solution of the Cauchy operator Problem $$displaylines{ dot{Y}(t=-Y(tA(t+ e^{i mu t}(I-P ,quad tgeq s cr Y(s=0, }$$ has a limit in $mathcal{L}(mathbb{C}^n$ as s tends to $-infty$ which is bounded uniformly with respect to the parameter $mu$. Here, ${ U(t,s: t, sinmathbb{R}}$ is the evolution family generated by ${A(t}_{tin mathbb{R}}$, $mu$ is a real number and q is a fixed positive number.

  1. Parameter Estimation and Model Selection for Mixtures of Truncated Exponentials

    DEFF Research Database (Denmark)

    Langseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael

    2010-01-01

    Bayesian networks with mixtures of truncated exponentials (MTEs) support efficient inference algorithms and provide a flexible way of modeling hybrid domains (domains containing both discrete and continuous variables). On the other hand, estimating an MTE from data has turned out to be a difficult...

  2. Smith-Purcell oscillator in an exponential gain regime

    International Nuclear Information System (INIS)

    Schachter, L.; Ron, A.

    1988-01-01

    A Smith-Purcell oscillator with a thick electron beam is analyzed in its exponential gain regime. A threshold current less than 1[A] is found for a 1 mm wavelength; this threshold is much lower than that of a similar oscillator operating in a linear gain regime

  3. The exponential age distribution and the Pareto firm size distribution

    OpenAIRE

    Coad, Alex

    2008-01-01

    Recent work drawing on data for large and small firms has shown a Pareto distribution of firm size. We mix a Gibrat-type growth process among incumbents with an exponential distribution of firm’s age, to obtain the empirical Pareto distribution.

  4. Minimal requirements for exponential growth of Lactococcus lactis

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Hammer, Karin

    1993-01-01

    A minimal growth medium containing glucose, acetate, vitamins, and eight amino acids allowed for growth of Lactococcus lactis subsp. lactis, with a specific growth rate in batch culture of mu = 0.3 h-1. With 19 amino acids added, the growth rate increased to mu = 0.7 h-1 and the exponential growth...

  5. Blowing-up semilinear wave equation with exponential nonlinearity ...

    Indian Academy of Sciences (India)

    Indian Acad. Sci. (Math. Sci.) Vol. 123, No. 3, August 2013, pp. 365–372. c Indian Academy of Sciences. Blowing-up semilinear wave equation with exponential nonlinearity in two space dimensions. T SAANOUNI. Department of Mathematics, Faculty of Sciences of Tunis,. University of Tunis El Manar, El Manar 2092, Tunisia.

  6. A fourth order exponentially-fitted multiderivative method for Stiff ...

    African Journals Online (AJOL)

    A fourth order exponentially-fitted multiderivative method for Stiff initial value problems. ... Journal of the Nigerian Association of Mathematical Physics ... implemented and preliminary numerical results indicate that the approach compares favourably with other existing methods that have solved the same set of stiff problems.

  7. Exponential decay for solutions to semilinear damped wave equation

    KAUST Repository

    Gerbi, Stéphane

    2011-10-01

    This paper is concerned with decay estimate of solutions to the semilinear wave equation with strong damping in a bounded domain. Intro- ducing an appropriate Lyapunov function, we prove that when the damping is linear, we can find initial data, for which the solution decays exponentially. This result improves an early one in [4].

  8. Calculation of the exponential function of linear idempotent operators

    International Nuclear Information System (INIS)

    Chavoya-Aceves, O.; Luna, H.M.

    1989-01-01

    We give a method to calculate the exponential EXP[A r ] where A is a linear operator which satisfies the reaction A n =I, n is an integer and I is the identity operator. The method is generalised to operators such that A n +1=A and is applied to obtain some Lorentz transformations which generalise the notion of 'boost'. (Author)

  9. Double Exponential Relativity Theory Coupled Theoretically with Quantum Theory?

    International Nuclear Information System (INIS)

    Montero Garcia, Jose de la Luz; Novoa Blanco, Jesus Francisco

    2007-01-01

    Here the problem of special relativity is analyzed into the context of a new theoretical formulation: the Double Exponential Theory of Special Relativity with respect to which the current Special or Restricted Theory of Relativity (STR) turns to be a particular case only

  10. Exploring parameter constraints on quintessential dark energy: The exponential model

    International Nuclear Information System (INIS)

    Bozek, Brandon; Abrahamse, Augusta; Albrecht, Andreas; Barnard, Michael

    2008-01-01

    We present an analysis of a scalar field model of dark energy with an exponential potential using the Dark Energy Task Force (DETF) simulated data models. Using Markov Chain Monte Carlo sampling techniques we examine the ability of each simulated data set to constrain the parameter space of the exponential potential for data sets based on a cosmological constant and a specific exponential scalar field model. We compare our results with the constraining power calculated by the DETF using their 'w 0 -w a ' parametrization of the dark energy. We find that respective increases in constraining power from one stage to the next produced by our analysis give results consistent with DETF results. To further investigate the potential impact of future experiments, we also generate simulated data for an exponential model background cosmology which cannot be distinguished from a cosmological constant at DETF 'Stage 2', and show that for this cosmology good DETF Stage 4 data would exclude a cosmological constant by better than 3σ

  11. Exponential inequalities for self-normalized martingales with applications

    OpenAIRE

    Bercu, Bernard; Touati, Abderrahmen

    2007-01-01

    International audience; We propose several exponential inequalities for self-normalized martingales similar to those established by De la Pena. The keystone is the introduction of a new notion of random variable heavy on left or right. Applications associated with linear regressions, autoregressive and branching processes are also provided.

  12. Mean square exponential stability of stochastic delayed Hopfield neural networks

    International Nuclear Information System (INIS)

    Wan Li; Sun Jianhua

    2005-01-01

    Stochastic effects to the stability property of Hopfield neural networks (HNN) with discrete and continuously distributed delay are considered. By using the method of variation parameter, inequality technique and stochastic analysis, the sufficient conditions to guarantee the mean square exponential stability of an equilibrium solution are given. Two examples are also given to demonstrate our results

  13. A new test for random events of an exponential distribution

    International Nuclear Information System (INIS)

    Schmidt, K.H.

    2000-03-01

    A new statistical test procedure is described to evaluate whether a set of radioactive-decay data is compatible with the assumption that these data originate from the decay of a single radioactive species. Criteria to detect contributions from other radioactive species and from different event sources are given. The test is applicable to samples of exponential distributions with two or more events. (orig.)

  14. Approximating Exponential and Logarithmic Functions Using Polynomial Interpolation

    Science.gov (United States)

    Gordon, Sheldon P.; Yang, Yajun

    2017-01-01

    This article takes a closer look at the problem of approximating the exponential and logarithmic functions using polynomials. Either as an alternative to or a precursor to Taylor polynomial approximations at the precalculus level, interpolating polynomials are considered. A measure of error is given and the behaviour of the error function is…

  15. The generalized exponential function and fractional trigonometric identities

    KAUST Repository

    Radwan, Ahmed G.

    2011-08-01

    In this work, we recall the generalized exponential function in the fractional-order domain which enables defining generalized cosine and sine functions. We then re-visit some important trigonometric identities and generalize them from the narrow integer-order subset to the more general fractional-order domain. Generalized hyperbolic function relations are also given. © 2011 IEEE.

  16. The star exponential and path integrals on compact groups

    Energy Technology Data Exchange (ETDEWEB)

    Cadavid, A.C. (Dept. of Physics and Astronomy, California State Univ., Northridge (United States)); Nakashima, M. (Dept. of Physics, TEP, UCLA, Los Angeles, CA (United States))

    1991-10-01

    Using the star exponential, a path integral is constructed for arbitrary compact Lie groups. This is a globalization of the results of Alcalde, Cadavid, and Nakashima, in which a path integral was constructed for SU(2) in terms of local coordinates. Also the phase factor encountered by Alcalde, Cadavid, and Nakashima is shown to be zero. (orig.).

  17. RMS slope of exponentially correlated surface roughness for radar applications

    DEFF Research Database (Denmark)

    Dierking, Wolfgang

    2000-01-01

    In radar signature analysis, the root mean square (RMS) surface slope is utilized to assess the relative contribution of multiple scattering effects. For an exponentially correlated surface, an effective RMS slope can be determined by truncating the high frequency tail of the roughness spectrum...

  18. Exponential stability of dynamic equations on time scales

    Directory of Open Access Journals (Sweden)

    Raffoul Youssef N

    2005-01-01

    Full Text Available We investigate the exponential stability of the zero solution to a system of dynamic equations on time scales. We do this by defining appropriate Lyapunov-type functions and then formulate certain inequalities on these functions. Several examples are given.

  19. Progress, Exponential Growth and Post-Growth Education

    Science.gov (United States)

    Irwin, Ruth

    2017-01-01

    Teleological progress is the underlying motif of modern culture, and informs education, innovation, and economic development. Progress includes a gradual increase in consumerism. Since the 1940s, the Keynesian Settlement and its embedded belief in progress is legislated in exponential 2-3% economic growth. Unfortunately, climate change is a direct…

  20. Construction of extended exponential general linear methods 524 ...

    African Journals Online (AJOL)

    This paper introduces a new approach for constructing higher order of EEGLM which have become very popular and novel due to its enviable stability properties. This paper also shows that methods 524 is stable with its characteristics root lies in a unit circle. Numerical experiments indicate that Extended Exponential ...

  1. Criteria for exponential asymptotic stability in the large of ...

    African Journals Online (AJOL)

    The purpose of this study is to provide necessary and sufficient conditions for exponential asymptotic stability in the large and uniform asymptotic stability of perturbations of linear systems with unbounded delays. A strong relationship is established between the two types of asymptotic stability. It is found that if the ...

  2. Almost sure exponential stability of delayed cellular neural networks

    Directory of Open Access Journals (Sweden)

    Chuangxia Huang

    2007-03-01

    Full Text Available The stability of stochastic delayed Cellular Neural Networks (DCNN is investigated in this paper. Using suitable Lyapunov functional and the semimartingale convergence theorem, we obtain some sufficient conditions for checking the almost sure exponential stability of the DCNN.

  3. Statistical exponential distribution function as distance indicator to stellar groups

    Science.gov (United States)

    Abdel Rahman, H.; Sabry, M. A.; Issa, I. A.

    2012-12-01

    In this paper, statistical distribution functions are developed for distance determination of stellar groups. This method depends on the assumption that, absolute magnitudes and apparent magnitudes follow an exponential distribution function. The developed approaches have been implemented to determine distances of some clusters and stellar associations. The comparison with the distances derived by different authors revealed good agreement.

  4. On root mean square approximation by exponential functions

    OpenAIRE

    Sharipov, Ruslan

    2014-01-01

    The problem of root mean square approximation of a square integrable function by finite linear combinations of exponential functions is considered. It is subdivided into linear and nonlinear parts. The linear approximation problem is solved. Then the nonlinear problem is studied in some particular example.

  5. The Exponential Distribution and the Application to Markov Models ...

    African Journals Online (AJOL)

    ... are close to zero, and very long times are increasingly unlikely. That is, the most likely values are considered to be clustered about the mean, and large deviations from the mean are viewed as increasingly unlike. If this characteristic of the negative exponential distribution seems incompatible with the application one has ...

  6. Unsteady MHD flow in porous media past over exponentially ...

    African Journals Online (AJOL)

    In this paper we are studying unsteady MHD flow in porous media past over exponentially accelerated inclined plate having variable wall temperature as well as mass transfer along with Hall current. We have used Laplace-transform technique to find the solution of the equations in the flow model. The results obtained are ...

  7. [Family form of isolated left ventricular noncompaction; case of a mother and her son observed in Gabon].

    Science.gov (United States)

    Mipinda, J B; Ibaba, J; Nkoghe, D D; Kombila, P A

    2013-02-01

    We describe a case report of a young Gabonese lady who presented an acute pulmonary oedema and we suspected a paripartum cardiomyopathy. Subsequent investigations showed isolated left ventricular noncompaction. A few months later, the same disease was disclosed at her 9 year-old son who presented a cardiac insufficiency. Therefore, we suspect a family form of left ventricular noncompaction. And it is the first description in subsaharan Africa. The hereditary character of this new form of cardiomyopathy linked to a genetic mutation on the X chromosome is well known. This disease is associated with heart failure, high incidence of systemic thromboembolism complications or ventricular arrhythmia. The echocardiography and the cardiac magnetic resonance imaging has been reported to be tools for diagnosis. In Africa, access to these techniques remains a privilege. So the discovery of illness is often late and the family screening are special. In our area, the therapeutic management is the medical treatment of heart failure. Implatable cardioverter defibrillator or heart transplantation are not available. So long-term prognosis of our patients with congestive heart failure stays poor. With best equipment in our hospitals and good training of African cardiologists, we should improve the management of our patients. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  8. Time-resolved infrared stimulated luminescence signals in feldspars: Analysis based on exponential and stretched exponential functions

    International Nuclear Information System (INIS)

    Pagonis, V.; Morthekai, P.; Singhvi, A.K.; Thomas, J.; Balaram, V.; Kitis, G.; Chen, R.

    2012-01-01

    Time-resolved infrared-stimulated luminescence (TR-IRSL) signals from feldspar samples have been the subject of several recent experimental studies. These signals are of importance in the field of luminescence dating, since they exhibit smaller fading effects than the commonly employed continuous-wave infrared signals (CW-IRSL). This paper presents a semi-empirical analysis of TR-IRSL data from feldspar samples, by using a linear combination of exponential and stretched exponential (SE) functions. The best possible estimates of the five parameters in this semi-empirical approach are obtained using five popular commercially available software packages, and by employing a variety of global optimization techniques. The results from all types of software and from the different fitting algorithms were found to be in close agreement with each other, indicating that a global optimum solution has likely been reached during the fitting process. Four complete sets of TR-IRSL data on well-characterized natural feldspars were fitted by using such a linear combination of exponential and SE functions. The dependence of the extracted fitting parameters on the stimulation temperature is discussed within the context of a recently proposed model of luminescence processes in feldspar. Three of the four feldspar samples studied in this paper are K-rich, and these exhibited different behavior at higher stimulation temperatures, than the fourth sample which was a Na-rich feldspar. The new method of analysis proposed in this paper can help isolate mathematically the more thermally stable components, and hence could lead to better dating applications in these materials. - Highlights: ► TR-IRSL from four feldspars were analyzed using exponential and stretched exponential functions. ► A variety of global optimization techniques give good agreement. ► Na-rich sample behavior is different from the three K-rich samples. ► Experimental data are fitted for stimulation temperatures

  9. Sub-exponential spin-boson decoherence in a finite bath

    International Nuclear Information System (INIS)

    Wong, V.; Gruebele, M.

    2002-01-01

    We investigate the decoherence of a two-level system coupled to harmonic baths of 4-21 degrees of freedom, to baths with internal anharmonic couplings, and to baths with an additional 'solvent shell' (modes coupled to other bath modes, but not to the system). The discrete spectral densities are chosen to mimic the highly fluctuating spectral densities computed for real systems such as proteins. System decoherence is computed by exact quantum dynamics. With realistic parameter choices (finite temperature, reasonably large couplings), sub-exponential decoherence of the two-level system is observed. Empirically, the time-dependence of decoherence can be fitted by power laws with small exponents. Intrabath anharmonic couplings are more effective at smoothing the spectral density and restoring exponential dynamics, than additional bath modes or solvent shells. We conclude that at high temperature, the most important physical basis for exponential decays is anharmonicity of those few bath modes interacting most strongly with the system, not a large number of oscillators interacting with the system. We relate the current numerical simulations to models of anharmonically coupled oscillators, which also predict power law dynamics. The potential utility of power law decays in quantum computation and condensed phase coherent control are also discussed

  10. Well hydraulics in pumping tests with exponentially decayed rates of abstraction in confined aquifers

    Science.gov (United States)

    Wen, Zhang; Zhan, Hongbin; Wang, Quanrong; Liang, Xing; Ma, Teng; Chen, Chen

    2017-05-01

    Actual field pumping tests often involve variable pumping rates which cannot be handled by the classical constant-rate or constant-head test models, and often require a convolution process to interpret the test data. In this study, we proposed a semi-analytical model considering an exponentially decreasing pumping rate started at a certain (higher) rate and eventually stabilized at a certain (lower) rate for cases with or without wellbore storage. A striking new feature of the pumping test with an exponentially decayed rate is that the drawdowns will decrease over a certain period of time during intermediate pumping stage, which has never been seen before in constant-rate or constant-head pumping tests. It was found that the drawdown-time curve associated with an exponentially decayed pumping rate function was bounded by two asymptotic curves of the constant-rate tests with rates equaling to the starting and stabilizing rates, respectively. The wellbore storage must be considered for a pumping test without an observation well (single-well test). Based on such characteristics of the time-drawdown curve, we developed a new method to estimate the aquifer parameters by using the genetic algorithm.

  11. A large collapsed-state RNA can exhibit simple exponential single-molecule dynamics.

    Science.gov (United States)

    Smith, Glenna J; Lee, Kang Taek; Qu, Xiaohui; Xie, Zheng; Pesic, Jelena; Sosnick, Tobin R; Pan, Tao; Scherer, Norbert F

    2008-05-09

    The process of large RNA folding is believed to proceed from many collapsed structures to a unique functional structure requiring precise organization of nucleotides. The diversity of possible structures and stabilities of large RNAs could result in non-exponential folding kinetics (e.g. stretched exponential) under conditions where the molecules have not achieved their native state. We describe a single-molecule fluorescence resonance energy transfer (FRET) study of the collapsed-state region of the free energy landscape of the catalytic domain of RNase P RNA from Bacillus stearothermophilus (C(thermo)). Ensemble measurements have shown that this 260 residue RNA folds cooperatively to its native state at >or=1 mM Mg(2+), but little is known about the conformational dynamics at lower ionic strength. Our measurements of equilibrium conformational fluctuations reveal simple exponential kinetics that reflect a small number of discrete states instead of the expected inhomogeneous dynamics. The distribution of discrete dwell times, collected from an "ensemble" of 300 single molecules at each of a series of Mg(2+) concentrations, fit well to a double exponential, which indicates that the RNA conformational changes can be described as a four-state system. This finding is somewhat unexpected under [Mg(2+)] conditions in which this RNA does not achieve its native state. Observation of discrete well-defined conformations in this large RNA that are stable on the seconds timescale at low [Mg(2+)] (<0.1 mM) suggests that even at low ionic strength, with a tremendous number of possible (weak) interactions, a few critical interactions may produce deep energy wells that allow for rapid averaging of motions within each well, and yield kinetics that are relatively simple.

  12. Modeling the pre-industrial roots of modern super-exponential population growth.

    Science.gov (United States)

    Stutz, Aaron Jonas

    2014-01-01

    To Malthus, rapid human population growth-so evident in 18th Century Europe-was obviously unsustainable. In his Essay on the Principle of Population, Malthus cogently argued that environmental and socioeconomic constraints on population rise were inevitable. Yet, he penned his essay on the eve of the global census size reaching one billion, as nearly two centuries of super-exponential increase were taking off. Introducing a novel extension of J. E. Cohen's hallmark coupled difference equation model of human population dynamics and carrying capacity, this article examines just how elastic population growth limits may be in response to demographic change. The revised model involves a simple formalization of how consumption costs influence carrying capacity elasticity over time. Recognizing that complex social resource-extraction networks support ongoing consumption-based investment in family formation and intergenerational resource transfers, it is important to consider how consumption has impacted the human environment and demography--especially as global population has become very large. Sensitivity analysis of the consumption-cost model's fit to historical population estimates, modern census data, and 21st Century demographic projections supports a critical conclusion. The recent population explosion was systemically determined by long-term, distinctly pre-industrial cultural evolution. It is suggested that modern globalizing transitions in technology, susceptibility to infectious disease, information flows and accumulation, and economic complexity were endogenous products of much earlier biocultural evolution of family formation's embeddedness in larger, hierarchically self-organizing cultural systems, which could potentially support high population elasticity of carrying capacity. Modern super-exponential population growth cannot be considered separately from long-term change in the multi-scalar political economy that connects family formation and

  13. Multinomial-exponential reliability function: a software reliability model

    International Nuclear Information System (INIS)

    Saiz de Bustamante, Amalio; Saiz de Bustamante, Barbara

    2003-01-01

    The multinomial-exponential reliability function (MERF) was developed during a detailed study of the software failure/correction processes. Later on MERF was approximated by a much simpler exponential reliability function (EARF), which keeps most of MERF mathematical properties, so the two functions together makes up a single reliability model. The reliability model MERF/EARF considers the software failure process as a non-homogeneous Poisson process (NHPP), and the repair (correction) process, a multinomial distribution. The model supposes that both processes are statistically independent. The paper discusses the model's theoretical basis, its mathematical properties and its application to software reliability. Nevertheless it is foreseen model applications to inspection and maintenance of physical systems. The paper includes a complete numerical example of the model application to a software reliability analysis

  14. Flexure of thick orthotropic plates by exponential shear deformation theory

    Directory of Open Access Journals (Sweden)

    A. S. Sayyad

    Full Text Available In the present paper, a variationally consistent exponential shear deformation theory taking into account transverse shear deformation effect is presented for the flexural analysis of thick orthotropic plates. The inplane displacement field uses exponential function in terms of thickness coordinate to include the shear deformation effect. The transverse shear stress can be obtained directly from the constitutive relations satisfying the shear stress free surface conditions on the top and bottom surfaces of the plate, hence the theory does not require shear correction factor. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. Results obtained for static flexure of simply supported orthotropic plates are compared with those of other refined theories and elasticity solution wherever applicable. The results obtained by present theory are in excellent agreement with those of exact results and other higher order theories. Thus the efficacy of the present refined theory is established.

  15. Optimization design of power efficiency of exponential impedance transformer

    International Nuclear Information System (INIS)

    Wang Meng; Zou Wenkang; Chen Lin; Guan Yongchao; Fu Jiabin; Xie Weiping

    2011-01-01

    The paper investigates the optimization design of power efficiency of exponential impedance transformer with analytic method and numerical method. In numerical calculation, a sine wave Jantage with hypothesis of rising edge equivalence is regarded as the forward-going Jantage at input of transformer, and its dominant angular frequency is determined by typical rise-time of actual Jantage waveforms. At the same time, dissipative loss in water dielectric is neglected. The numerical results of three typical modes of impedance transformation, viz. linear mode, saturation mode and steep mode,are compared. Pivotal factors which affect the power efficiency of exponential impedance transformer are discussed, and a certain extent quantitative range of intermediate variables and accordance coefficients are obtained. Finally, the paper discusses some important issues in actual design, such as insulation safety factor in structure design, effects of coupling capacitance on impedance calculation, and dissipative loss in water dielectric. (authors)

  16. Handbook of exponential and related distributions for engineers and scientists

    CERN Document Server

    Pal, Nabendu; Lim, Wooi K

    2005-01-01

    The normal distribution is widely known and used by scientists and engineers. However, there are many cases when the normal distribution is not appropriate, due to the data being skewed. Rather than leaving you to search through journal articles, advanced theoretical monographs, or introductory texts for alternative distributions, the Handbook of Exponential and Related Distributions for Engineers and Scientists provides a concise, carefully selected presentation of the properties and principles of selected distributions that are most useful for application in the sciences and engineering.The book begins with all the basic mathematical and statistical background necessary to select the correct distribution to model real-world data sets. This includes inference, decision theory, and computational aspects including the popular Bootstrap method. The authors then examine four skewed distributions in detail: exponential, gamma, Weibull, and extreme value. For each one, they discuss general properties and applicabi...

  17. An Exact Analytical Solution to Exponentially Tapered Piezoelectric Energy Harvester

    Directory of Open Access Journals (Sweden)

    H. Salmani

    2015-01-01

    Full Text Available It has been proven that tapering the piezoelectric beam through its length optimizes the power extracted from vibration based energy harvesting. This phenomenon has been investigated by some researchers using semianalytical, finite element and experimental methods. In this paper, an exact analytical solution is presented to calculate the power generated from vibration of exponentially tapered unimorph and bimorph with series and parallel connections. The mass normalized mode shapes of the exponentially tapered piezoelectric beam with tip mass are implemented to transfer the proposed electromechanical coupled equations into modal coordinates. The steady states harmonic solution results are verified both numerically and experimentally. Results show that there exist values for tapering parameter and electric resistance in a way that the output power per mass of the energy harvester will be maximized. Moreover it is concluded that the electric resistance must be higher than a specified value for gaining more power by tapering the beam.

  18. Exponentials and Laplace transforms on nonuniform time scales

    Science.gov (United States)

    Ortigueira, Manuel D.; Torres, Delfim F. M.; Trujillo, Juan J.

    2016-10-01

    We formulate a coherent approach to signals and systems theory on time scales. The two derivatives from the time-scale calculus are used, i.e., nabla (forward) and delta (backward), and the corresponding eigenfunctions, the so-called nabla and delta exponentials, computed. With these exponentials, two generalised discrete-time Laplace transforms are deduced and their properties studied. These transforms are compatible with the standard Laplace and Z transforms. They are used to study discrete-time linear systems defined by difference equations. These equations mimic the usual continuous-time equations that are uniformly approximated when the sampling interval becomes small. Impulse response and transfer function notions are introduced. This implies a unified mathematical framework that allows us to approximate the classic continuous-time case when the sampling rate is high or to obtain the standard discrete-time case, based on difference equations, when the time grid becomes uniform.

  19. On the exponential of matrices in su(4)

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishna, Viswanath; Zhou, Hong [Department of Mathematical Sciences and Center for Signals, Systems and Communications, University of Texas at Dallas, PO Box 830688, Richardson, TX 75083 (United States)

    2006-03-24

    This paper provides explicit techniques to compute the exponentials of a variety of anti-Hermitian matrices in dimension 4. Many of these formulae can be written down directly from the entries of the matrix. Whenever any spectral calculations are required, these can be done in closed form. In many instances only 2 x 2 spectral calculations are required. These formulae cover a wide variety of applications. Conditions on the matrix which render it to admit one of three minimal polynomials are also given. Matrices with these minimal polynomials admit simple and tractable representations for their exponentials. One of these is the Euler-Rodrigues formula. The key technique is the relation between real 4 x 4 matrices and the quaternions.

  20. Predicting Escherichia coli's chemotactic drift under exponential gradient

    Science.gov (United States)

    Samanta, Sibendu; Layek, Ritwik; Kar, Shantimoy; Raj, M. Kiran; Mukhopadhyay, Sudipta; Chakraborty, Suman

    2017-09-01

    Bacterial species are known to show chemotaxis, i.e., the directed motions in the presence of certain chemicals, whereas the motion is random in the absence of those chemicals. The bacteria modulate their run time to induce chemotactic drift towards the attractant chemicals and away from the repellent chemicals. However, the existing theoretical knowledge does not exhibit a proper match with experimental validation, and hence there is a need for developing alternate models and validating experimentally. In this paper a more robust theoretical model is proposed to investigate chemotactic drift of peritrichous Escherichia coli under an exponential nutrient gradient. An exponential gradient is used to understand the steady state behavior of drift because of the logarithmic functionality of the chemosensory receptors. Our theoretical estimations are validated through the experimentation and simulation results. Thus, the developed model successfully delineates the run time, run trajectory, and drift velocity as measured from the experiments.

  1. Exponential Inequalities for Positively Associated Random Variables and Applications

    Directory of Open Access Journals (Sweden)

    Yang Shanchao

    2008-01-01

    Full Text Available Abstract We establish some exponential inequalities for positively associated random variables without the boundedness assumption. These inequalities improve the corresponding results obtained by Oliveira (2005. By one of the inequalities, we obtain the convergence rate for the case of geometrically decreasing covariances, which closes to the optimal achievable convergence rate for independent random variables under the Hartman-Wintner law of the iterated logarithm and improves the convergence rate derived by Oliveira (2005 for the above case.

  2. The need for interdisciplinary research on exponential technologies and sustainability

    OpenAIRE

    Alier Forment, Marc; Casany Guerrero, María José

    2017-01-01

    Technology has a clear influence on the way we live, our culture and how society functions, and last but not least our environment. At a moment when the transformational factor of technology is accelerating at an exponential pace, it is really important to reflect the direction that we want this acceleration to go. In this paper we present some of the factors relevant to this mater: 1) the influence of technology in the society and the environment. 2) The acceleration of some technologies ...

  3. Applications exponential approximation by integer shifts of Gaussian functions

    Directory of Open Access Journals (Sweden)

    S. M. Sitnik

    2013-01-01

    Full Text Available In this paper we consider approximations of functions using integer shifts of Gaussians – quadratic exponentials. A method is proposed to find coefficients of node functions by solving linear systems of equations. The explicit formula for the determinant of the system is found, based on it solvability of linear system under consideration is proved and uniqueness of its solution. We compare results with known ones and briefly indicate applications to signal theory.

  4. Exponential estimates for stochastic convolutions in 2-smooth Banach spaces

    Czech Academy of Sciences Publication Activity Database

    Seidler, Jan

    2010-01-01

    Roč. 15, č. 50 (2010), s. 1556-1573 ISSN 1083-6489 R&D Projects: GA ČR GA201/07/0237 Institutional research plan: CEZ:AV0Z10750506 Keywords : stochastic convolutions in 2-smooth spaces * Burkholder-Davis-Gundy inequality * exponential tail estimates Subject RIV: BA - General Mathematics Impact factor: 0.946, year: 2010 http://library.utia.cas.cz/separaty/2010/SI/seidler-0348352.pdf

  5. Tunability response in exponentially graded ferroelectrics: A TIM model approach

    Energy Technology Data Exchange (ETDEWEB)

    Vivas C, H., E-mail: hvivasc@unal.edu.co [Grupo de Propiedades Opticas de los Materiales, Departamento de Fisica, Bloque Y, Universidad Nacional de Colombia, Manizales A.A. 127 (Colombia); Jurado, J.F.; Vargas-Hernandez, C. [Grupo de Propiedades Opticas de los Materiales, Departamento de Fisica, Bloque Y, Universidad Nacional de Colombia, Manizales A.A. 127 (Colombia)

    2012-02-01

    Relative dielectric function response associate to a non-homogeneous layered ferroelectric system is calculated in the framework of the Mean Field Approximation (MFA) for the Transverse Ising Model (TIM). Analytical self-consistent expressions for the average polarization, dielectric susceptibility, and tunability percentage are outlined and solved for different configurations and sizes. It is found that exponentially graded ferroelectrics magnify the tunability response for stronger interlayer coupling and it reaches its saturation value for smaller intensities of the applied electric field.

  6. Resummation and power corrections by Dressed Gluon Exponentiation

    CERN Document Server

    Gardi, Einan; Gardi, Einan; Rathsman, Johan

    2002-01-01

    Event-shape distributions in $e^+e^-$ annihilation offer a unique lab oratory for understanding perturbative and non-perturbative aspects of QCD. Dressed Gluon Exponentiation is a resummation method designed to evaluate differ ential cross sections close to a kinematic threshold and provide the basis for parametrization of power corrections. The method and its application in the case of the thrust and the heavy jet mass distributions in the two-jet region are briefly presented.

  7. Validation of predicted exponential concentration profiles of chemicals in soils

    International Nuclear Information System (INIS)

    Hollander, Anne; Baijens, Iris; Ragas, Ad; Huijbregts, Mark; Meent, Dik van de

    2007-01-01

    Multimedia mass balance models assume well-mixed homogeneous compartments. Particularly for soils, this does not correspond to reality, which results in potentially large uncertainties in estimates of transport fluxes from soils. A theoretically expected exponential decrease model of chemical concentrations with depth has been proposed, but hardly tested against empirical data. In this paper, we explored the correspondence between theoretically predicted soil concentration profiles and 84 field measured profiles. In most cases, chemical concentrations in soils appear to decline exponentially with depth, and values for the chemical specific soil penetration depth (d p ) are predicted within one order of magnitude. Over all, the reliability of multimedia models will improve when they account for depth-dependent soil concentrations, so we recommend to take into account the described theoretical exponential decrease model of chemical concentrations with depth in chemical fate studies. In this model the d p -values should estimated be either based on local conditions or on a fixed d p -value, which we recommend to be 10 cm for chemicals with a log K ow > 3. - Multimedia mass model predictions will improve when taking into account depth dependent soil concentrations

  8. Identifying Employment Subcenters: The Method of Exponentially Declining Cutoffs

    Directory of Open Access Journals (Sweden)

    Jifei Ban

    2017-03-01

    Full Text Available The standard method of identifying subcenters is due to Giuliano and Small. While simple, robust and easy to apply, because it uses absolute employment density and employment cutoffs, it identifies “too few” subcenters at the metropolitan periphery. This paper presents a straight forward modification to this method aimed at remedying this weakness. The modification entails using cutoffs that decline exponentially with distance from the metropolitan center, thereby giving consideration to the employment density of a location relative to that of its locality. In urban studies, there is a long history of estimating employment density “gradients”, the exponential rate at which employment density declines with distance from the metropolitan center. These density gradients differ substantially across metropolitan areas and across time for a particular metropolitan area. Applying our method to Los Angeles, Calgary and Paris, we have found that using cutoffs that decline exponentially at one-half the estimated density gradients achieves an appealing balance between subcenters identified close to the metropolitan center and those identified at the metropolitan periphery. Many other methods of subcenter identification have been proposed that use sophisticated econometric procedures. Our method should appeal to practitioners who are looking for a simple method to apply.

  9. Exponentiation and deformations of Lie-admissible algebras

    International Nuclear Information System (INIS)

    Myung, H.C.

    1982-01-01

    The exponential function is defined for a finite-dimensional real power-associative algebra with unit element. The application of the exponential function is focused on the power-associative (p,q)-mutation of a real or complex associative algebra. Explicit formulas are computed for the (p,q)-mutation of the real envelope of the spin 1 algebra and the Lie algebra so(3) of the rotation group, in light of earlier investigations of the spin 1/2. A slight variant of the mutated exponential is interpreted as a continuous function of the Lie algebra into some isotope of the corresponding linear Lie group. The second part of this paper is concerned with the representation and deformation of a Lie-admissible algebra. The second cohomology group of a Lie-admissible algebra is introduced as a generalization of those of associative and Lie algebras in the Hochschild and Chevalley-Eilenberg theory. Some elementary theory of algebraic deformation of Lie-admissible algebras is discussed in view of generalization of that of associative and Lie algebras. Lie-admissible deformations are also suggested by the representation of Lie-admissible algebras. Some explicit examples of Lie-admissible deformation are given in terms of the (p,q)-mutation of associative deformation of an associative algebra. Finally, we discuss Lie-admissible deformations of order one

  10. Evidence for Truncated Exponential Probability Distribution of Earthquake Slip

    KAUST Repository

    Thingbaijam, Kiran K. S.

    2016-07-13

    Earthquake ruptures comprise spatially varying slip on the fault surface, where slip represents the displacement discontinuity between the two sides of the rupture plane. In this study, we analyze the probability distribution of coseismic slip, which provides important information to better understand earthquake source physics. Although the probability distribution of slip is crucial for generating realistic rupture scenarios for simulation-based seismic and tsunami-hazard analysis, the statistical properties of earthquake slip have received limited attention so far. Here, we use the online database of earthquake source models (SRCMOD) to show that the probability distribution of slip follows the truncated exponential law. This law agrees with rupture-specific physical constraints limiting the maximum possible slip on the fault, similar to physical constraints on maximum earthquake magnitudes.We show the parameters of the best-fitting truncated exponential distribution scale with average coseismic slip. This scaling property reflects the control of the underlying stress distribution and fault strength on the rupture dimensions, which determines the average slip. Thus, the scale-dependent behavior of slip heterogeneity is captured by the probability distribution of slip. We conclude that the truncated exponential law accurately quantifies coseismic slip distribution and therefore allows for more realistic modeling of rupture scenarios. © 2016, Seismological Society of America. All rights reserverd.

  11. A 1.5-Mb deletion in 17p11.2-p12 is frequently observed in Italian families with hereditary neuropathy with liability to pressure palsies

    Energy Technology Data Exchange (ETDEWEB)

    Lorenzetti, D.; Pandolfo, M. [Istituto Nazionale Neurologico, Milan (Italy)]|[Baylor College of Medicine, Houston, TX (United States); Pareyson, D.; Sghirlanzoni, A.; Di Donato, S. [Istituto Nazionale Neurologico, Milan (Italy); Roa, B.B.; Abbas, N.E.; Lupski, J.R. [Baylor College of Medicine, Houston, TX (United States)

    1995-01-01

    Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disorder characterized by recurrent mononeuropathies. A 1.5-Mb deletion in chromosome 17p11.2-p12 has been associated with HNPP. Duplication of the same 1.5-Mb region is known to be associated with Charcot-Marie-Tooth disease type 1 (CMT1A), a more severe peripheral neuropathy characterized by symmetrically slowed nerve conduction velocity (NCV). The CMT1A duplication and HNPP deletion appear to be the reciprocal products of a recombination event involving a repeat element (CMT1A-REP) that flanks the 1.5-Mb region involved in the duplication/deletion. Patients from nine unrelated Italian families who were diagnosed with HNPP on the basis of clinical, electrophysiological, and histological evaluations were analyzed by molecular methods for DNA deletion on chromosome 17p. In all nine families, Southern analysis using a CMT1A-REP probe detected a reduced hybridization signal of a 6.0-kb EcoRI fragment mapping within the distal CMT1A-REP, indicating deletion of one copy of CMT1A-REP in these HNPP patients. Families were also typed with a polymorphic (CA){sub n} repeat and with RFLPs corresponding to loci D17S122, D17S125, and D17S61, which all map within the deleted region. Lack of allelic transmission from affected parent to affected offspring was observed in four informative families, providing an independent indication for deletion. Furthermore, pulsed-field gel electrophoresis analysis of SacII-digested genomic DNA detected junction fragments specific to the 1.5-Mb HNPP deletion in seven of nine Italian families included in this study. These findings suggest that a 1.5-Mb deletion on 17p11.2-p12 is the most common mutation associated with HNPP. 51 refs., 5 figs., 1 tab.

  12. Observed parental responsiveness/warmth and children's coping: cross-sectional and prospective relations in a family depression preventive intervention.

    Science.gov (United States)

    Watson, Kelly H; Dunbar, Jennifer P; Thigpen, Jennifer; Reising, Michelle M; Hudson, Kelsey; McKee, Laura; Forehand, Rex; Compas, Bruce E

    2014-06-01

    The current study examined concurrent and prospective relations between observed parenting behaviors and children's coping strategies in the context of a preventive intervention designed to change both parenting and children's use of secondary control coping. Questionnaires and direct observations were obtained from parents with a history of depression (N = 180) and their children (ages 9-15 years) at baseline, 6-month (after completion of the intervention), and 18-month follow-up assessments. Cross-sectional analyses indicate that baseline observed parental responsiveness/warmth was significantly associated with composite parent/child reports of children's baseline primary control, secondary control, and disengagement coping. Using a mixed effects model, prospective mediational analyses indicate that intervention-driven improvements in observed parental responsiveness/warmth from baseline to 6 months significantly accounted for increases in children's use of secondary control coping strategies from baseline to the 18-month follow-up assessment. No significant mediation effects emerged for primary control coping or disengagement coping. The present findings suggest that it may be possible to improve children's coping strategies not only through targeted interventions, but also indirectly by improving responsive and warm parenting behaviors. Limitations and strengths are noted and implications for future research are outlined. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  13. Connecting LADEE LDEX Observations of the Moon's dust cloud to the temporal and selenographic variability produced by micrometeoroid impacts from Jupiter Family Comets

    Science.gov (United States)

    Janches, D.; Pokorny, P.; Sarantos, M.; Nesvorny, D.

    2017-12-01

    Recent observations by the Lunar Dust Experiment (LDEX) on board NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) were perceived to indicate an unbalanced influence of meteoroids impacting from the Helion and the Anti-Helion directions. These observations were interpreted without proper consideration of the dynamical characteristics of the meteoroid environment and its spatio-temporal influence on the Moon's surface. In this work, a dynamical model of meteoroids originating from Jupiter Family Comets is utilized to model the secondary dust ejecta cloud engulfing the Moon. It is shown that the combination of the dynamical properties of these meteoroids, together with the orbital geometry of LADEE, introduce a bias in the observations and causes LADEE LDEX to be more sensitive to the Helion source. This effect must be considered in order to draw accurate conclusions regarding the meteoroid environment and its influence on the Moon's surface.

  14. An unusual DNA sequence observed in the. gamma. globin gene loci of two members of a Chinese family

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Q.C.

    1989-01-01

    There are two nonallelic human {gamma} globin genes located on the short arm of chromosome No. 11 in the order 5{prime}-{sup G}{sub {gamma}}-{sup A}{sub {gamma}}-3{prime}. Various modifications of the two {gamma} genes have been reported and include: deletions, triplications, quadruplications and recently a quintuplication. These are generally created by one or more unequal crossovers in the {gamma} globin gene regions on adjacent chromosomes. During the course of looking for a {gamma}{sup {degree}} thalassemia, which might be due to a crossover of looking for a {gamma} genes, two cases were found in the family W. Bgl II mapping studies showed a 5 kb deletion at the {gamma} gene loci in these individuals. The Bgl II fragment from the {gamma} gene loci of R.W. was cloned into the phage vector QR1. Phage mapping showed that two out of the three Pst I sites within the Bgl II fragment were missing which suggested that the crossover might have occurred within the {gamma} gene, possibly within the {gamma}IVS II region. Sequence analysis of the cloned fragment revealed an unusual sequence which had no sequence homology with the {gamma} gene region except for a small 264 bp region near the 3{prime} end. The orientation of the 264 bp fragment is inverted relative to homologous sequences in the {sup G}{sub {gamma}} and {sup A}{sub {gamma}} IVS II. The unusual sequence was computer analyzed for homology with every DNA sequence file in the EMBL database and GenBank and did not show any significant homologies to all the available DNA sequences except for the 264 bp {gamma}IVS II homology.

  15. Exponentiated Transmuted Generalized Raleigh Distribution: A New Four Parameter Rayleigh Distribution

    Directory of Open Access Journals (Sweden)

    Ahmed Z. A…fify

    2015-04-01

    Full Text Available This paper introduces a new four parameter Rayleigh distribution as a generalization of the transmuted generalized Rayleigh distribution introduced by Merovci (2014. The new distribution is referred to as exponentiated transmuted generalized Rayleigh distribution (ETGRD. Various structural properties of the new distribution including moments, quantiles, moment generating function and RØnyi entropy of the subject distribution are derived. We proposed the method of maximum likelihood for estimating the model parameters and obtain the observed information matrix. A two real data sets are used to compare the ‡exibility of the new model versus its sub models.

  16. Time-domain full waveform inversion of exponentially damped wavefield using the deconvolution-based objective function

    KAUST Repository

    Choi, Yun Seok

    2017-11-15

    Full waveform inversion (FWI) suffers from the cycle-skipping problem when the available frequency-band of data is not low enough. We apply an exponential damping to the data to generate artificial low frequencies, which helps FWI avoid cycle skipping. In this case, the least-square misfit function does not properly deal with the exponentially damped wavefield in FWI, because the amplitude of traces decays almost exponentially with increasing offset in a damped wavefield. Thus, we use a deconvolution-based objective function for FWI of the exponentially damped wavefield. The deconvolution filter includes inherently a normalization between the modeled and observed data, thus it can address the unbalanced amplitude of a damped wavefield. We, specifically, normalize the modeled data with the observed data in the frequency-domain to estimate the deconvolution filter and selectively choose a frequency-band for normalization that mainly includes the artificial low frequencies. We calculate the gradient of the objective function using the adjoint-state method. The synthetic and benchmark data examples show that our FWI algorithm generates a convergent long wavelength structure without low frequency information in the recorded data.

  17. Exponential and power laws in public procurement markets

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav; Skuhrovec, J.

    2012-01-01

    Roč. 99, č. 2 (2012), 28005-1-28005-6 ISSN 0295-5075 R&D Projects: GA ČR GA402/09/0965 Grant - others:GA UK(CZ) 118310; SVV(CZ) 265 504; GA TA ČR(CZ) TD010133 Institutional support: RVO:67985556 Keywords : Public procurement * Scaling * Power law Subject RIV: AH - Economics Impact factor: 2.260, year: 2012 http://library.utia.cas.cz/separaty/2012/E/kristoufek-exponential and power laws in public procurement markets.pdf

  18. Exponential Martingales and Changes of Measure for Counting Processes

    DEFF Research Database (Denmark)

    Sokol, Alexander; Hansen, Niels Richard

    2015-01-01

    We give sufficient criteria for the Doléans-Dade exponential of a stochastic integral with respect to a counting process local martingale to be a true martingale. The criteria are adapted particularly to the case of counting processes and are sufficiently weak to be useful and verifiable, as we i...... illustrate by several examples. In particular, the criteria allow for the construction of for example nonexplosive Hawkes processes, counting processes with stochastic intensities depending on diffusion processes as well as inhomogeneous finite-state Markov processes....

  19. Exponential complexity and ontological theories of quantum mechanics

    International Nuclear Information System (INIS)

    Montina, A.

    2008-01-01

    Ontological theories of quantum mechanics describe a single system by means of well-defined classical variables and attribute the quantum uncertainties to our ignorance about the underlying reality represented by these variables. We consider the general class of ontological theories describing a quantum system by a set of variables with Markovian (either deterministic or stochastic) evolution. We provide proof that the number of continuous variables cannot be smaller than 2N-2, N being the Hilbert-space dimension. Thus, any ontological Markovian theory of quantum mechanics requires a number of variables which grows exponentially with the physical size. This result is relevant also in the framework of quantum Monte Carlo methods

  20. Exponential Decay of Covariances for the Supercritical Membrane Model

    Science.gov (United States)

    Bolthausen, Erwin; Cipriani, Alessandra; Kurt, Noemi

    2017-08-01

    We consider the membrane model, that is the centered Gaussian field on {\\mathbb{Z}^d} whose covariance matrix is given by the inverse of the discrete Bilaplacian. We impose a {δ}-pinning condition, giving a reward of strength {\\varepsilon} for the field to be 0 at any site of the lattice. In this paper we prove that in dimensions {d≥ 5} covariances of the pinned field decay at least exponentially, as opposed to the field without pinning, where the decay is polynomial. The proof is based on estimates for certain discrete weighted norms, a percolation argument and on a Bernoulli domination result.

  1. Exponential Time Complexity of the Permanent and the Tutte Polynomial

    DEFF Research Database (Denmark)

    Dell, Holger; Husfeldt, Thore; Marx, Dániel

    2014-01-01

    bounds are relative to (variants of) the Exponential Time Hypothesis (ETH), which says that the satisfiability of n-variable 3-CNF formulas cannot be decided in time exp(o(n)). We relax this hypothesis by introducing its counting version #ETH; namely, that the satisfying assignments cannot be counted......We show conditional lower bounds for well-studied #P-hard problems: The number of satisfying assignments of a 2-CNF formula with n variables cannot be computed in time exp(o(n)), and the same is true for computing the number of all independent sets in an n-vertex graph. The permanent of an n× n...

  2. Neural pulse frequency modulation of an exponentially correlated Gaussian process

    Science.gov (United States)

    Hutchinson, C. E.; Chon, Y.-T.

    1976-01-01

    The effect of NPFM (Neural Pulse Frequency Modulation) on a stationary Gaussian input, namely an exponentially correlated Gaussian input, is investigated with special emphasis on the determination of the average number of pulses in unit time, known also as the average frequency of pulse occurrence. For some classes of stationary input processes where the formulation of the appropriate multidimensional Markov diffusion model of the input-plus-NPFM system is possible, the average impulse frequency may be obtained by a generalization of the approach adopted. The results are approximate and numerical, but are in close agreement with Monte Carlo computer simulation results.

  3. Boundary layer flow of nanofluid over an exponentially stretching surface

    Science.gov (United States)

    Nadeem, Sohail; Lee, Changhoon

    2012-01-01

    The steady boundary layer flow of nanofluid over an exponential stretching surface is investigated analytically. The transport equations include the effects of Brownian motion parameter and thermophoresis parameter. The highly nonlinear coupled partial differential equations are simplified with the help of suitable similarity transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions are obtained by plotting h-curve. The expressions for velocity, temperature and nanoparticle volume fraction are computed for some values of the parameters namely, suction injection parameter α, Lewis number Le, the Brownian motion parameter Nb and thermophoresis parameter Nt.

  4. Polar exponential sensor arrays unify iconic and Hough space representation

    Science.gov (United States)

    Weiman, Carl F. R.

    1990-01-01

    The log-polar coordinate system, inherent in both polar exponential sensor arrays and log-polar remapped video imagery, is identical to the coordinate system of its corresponding Hough transform parameter space. The resulting unification of iconic and Hough domains simplifies computation for line recognition and eliminates the slope quantization problems inherent in the classical Cartesian Hough transform. The geometric organization of the algorithm is more amenable to massively parallel architectures than that of the Cartesian version. The neural architecture of the human visual cortex meets the geometric requirements to execute 'in-place' log-Hough algorithms of the kind described here.

  5. Boundary layer flow of nanofluid over an exponentially stretching surface.

    Science.gov (United States)

    Nadeem, Sohail; Lee, Changhoon

    2012-01-30

    The steady boundary layer flow of nanofluid over an exponential stretching surface is investigated analytically. The transport equations include the effects of Brownian motion parameter and thermophoresis parameter. The highly nonlinear coupled partial differential equations are simplified with the help of suitable similarity transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions are obtained by plotting h-curve. The expressions for velocity, temperature and nanoparticle volume fraction are computed for some values of the parameters namely, suction injection parameter α, Lewis number Le, the Brownian motion parameter Nb and thermophoresis parameter Nt.

  6. Optical nonlinearity of liquid nanosuspensions: Kerr versus exponential model

    Science.gov (United States)

    Wright, E. M.; Lee, W. M.; Dholakia, K.; El-Ganainy, R.; Christodoulides, D. N.

    2009-08-01

    We report our experimental and theoretical progress towards elucidating the nonlinear optical response of nanosuspensions. To date, we have devised a fiber-optic variant of the Z-scan method to accurately measure the nonlinearity of liquid nanosuspensions. Furthermore, we shall show that the optical nonlinearity may be properly accounted theoretically by including both the virial coefficients for the soft-condensed matter system in addition to the exponential term, which does not account for particleparticle interactions, yielding an effective or renormalized Kerr effect in many cases.

  7. On the stability of some systems of exponential difference equations

    Directory of Open Access Journals (Sweden)

    N. Psarros

    2018-01-01

    Full Text Available In this paper we prove the stability of the zero equilibria of two systems of difference equations of exponential type, which are some extensions of an one-dimensional biological model. The stability of these systems is investigated in the special case when one of the eigenvalues is equal to -1 and the other eigenvalue has absolute value less than 1, using centre manifold theory. In addition, we study the existence and uniqueness of positive equilibria, the attractivity and the global asymptotic stability of these equilibria of some related systems of difference equations.

  8. Exponential convergence and acceleration of Hartree-Fock calculations

    International Nuclear Information System (INIS)

    Bonaccorso, A.; Di Toro, M.; Lomnitz-Adler, J.

    1979-01-01

    It is shown that one can expect an exponential behaviour for the convergence of the Hartree-Fock solution during the HF iteration procedure. This property is used to extrapolate some collective degrees of freedom, in this case the shape, in order to speed up the self-consistent calculation. For axially deformed nuclei the method is applied to the quadrupole moment which corresponds to a simple scaling transformation on the single particle wave functions. Results are shown for the deformed nuclei 20 Ne and 28 Si with a Skyrme interaction. (Auth.)

  9. Finite differences with exponential filtering in the calculation of reactivity

    International Nuclear Information System (INIS)

    Suescun Diaz, Daniel; Senra Martinez, Aquilino

    2010-01-01

    A formulation for the calculation of reactivity using a recursive process is presented in this paper, as well as the treatment to reduce noise intensity that is found in the nuclear power signal. Using the history of nuclear power considered as the memory of such power and the filter exponentially adjusted with the least squares method, it is possible to reduce the nuclear power fluctuations without causing attenuation for the calculation of reactivity and with a smaller delay than that for low-pass filter of first order delay filter. (orig.)

  10. Finite differences with exponential filtering in the calculation of reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Suescun Diaz, Daniel; Senra Martinez, Aquilino [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). COPPE - Programa de Engenharia Nuclear

    2010-08-15

    A formulation for the calculation of reactivity using a recursive process is presented in this paper, as well as the treatment to reduce noise intensity that is found in the nuclear power signal. Using the history of nuclear power considered as the memory of such power and the filter exponentially adjusted with the least squares method, it is possible to reduce the nuclear power fluctuations without causing attenuation for the calculation of reactivity and with a smaller delay than that for low-pass filter of first order delay filter. (orig.)

  11. Exponential bound in the quest for absolute zero

    Science.gov (United States)

    Stefanatos, Dionisis

    2017-10-01

    In most studies for the quantification of the third law of thermodynamics, the minimum temperature which can be achieved with a long but finite-time process scales as a negative power of the process duration. In this article, we use our recent complete solution for the optimal control problem of the quantum parametric oscillator to show that the minimum temperature which can be obtained in this system scales exponentially with the available time. The present work is expected to motivate further research in the active quest for absolute zero.

  12. Stochastic convolutions driven by martingales: maximal inequalities and exponential integrability

    Czech Academy of Sciences Publication Activity Database

    Hausenblas, E.; Seidler, Jan

    2008-01-01

    Roč. 26, č. 1 (2008), s. 98-119 ISSN 0736-2994 Grant - others:Austrian Academy of Sciences(AT) APART 700; GA ČR(CZ) GA201/04/0750; GA ČR(CZ) GA201/01/1197; GA MSM(CZ) Kontakt 2001-05 Program:GA; GA Institutional research plan: CEZ:AV0Z10750506 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : maximal inequality * exponential tail estimates * stochastic convolution Subject RIV: BA - General Mathematics Impact factor: 0.528, year: 2008

  13. Exponential integrators for the incompressible Navier-Stokes equations.

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Christopher K.

    2004-07-01

    We provide an algorithm and analysis of a high order projection scheme for time integration of the incompressible Navier-Stokes equations (NSE). The method is based on a projection onto the subspace of divergence-free (incompressible) functions interleaved with a Krylov-based exponential time integration (KBEI). These time integration methods provide a high order accurate, stable approach with many of the advantages of explicit methods, and can reduce the computational resources over conventional methods. The method is scalable in the sense that the computational costs grow linearly with problem size. Exponential integrators, used typically to solve systems of ODEs, utilize matrix vector products of the exponential of the Jacobian on a vector. For large systems, this product can be approximated efficiently by Krylov subspace methods. However, in contrast to explicit methods, KBEIs are not restricted by the time step. While implicit methods require a solution of a linear system with the Jacobian, KBEIs only require matrix vector products of the Jacobian. Furthermore, these methods are based on linearization, so there is no non-linear system solve at each time step. Differential-algebraic equations (DAEs) are ordinary differential equations (ODEs) subject to algebraic constraints. The discretized NSE constitute a system of DAEs, where the incompressibility condition is the algebraic constraint. Exponential integrators can be extended to DAEs with linear constraints imposed via a projection onto the constraint manifold. This results in a projected ODE that is integrated by a KBEI. In this approach, the Krylov subspace satisfies the constraint, hence the solution at the advanced time step automatically satisfies the constraint as well. For the NSE, the projection onto the constraint is typically achieved by a projection induced by the L{sup 2} inner product. We examine this L{sup 2} projection and an H{sup 1} projection induced by the H{sup 1} semi-inner product. The H

  14. Prime Number: an Experiment Rabin-Miller and Fast Exponentiation

    Science.gov (United States)

    Rahim, Robbi; Winata, Hendryan; Zulkarnain, Iskandar; Jaya, Hendra

    2017-12-01

    Prime number is one of the most widely used names for various security purposes, especially in the process of encryption and decryption for asymmetric algorithms, the speed in determining prime number becomes one of the most important things, Rabin-Miller algorithm is used to test a number whether including prime or not, speed in determining prime number is very important and technique that could be using is fast exponentiation, this research get significant result in testing prime number with length of variation number.

  15. Evaluation of Moessbauer line diffusion broadening by exponential fit

    International Nuclear Information System (INIS)

    Kucera, Jaroslav; Kucera, Jan

    1978-01-01

    The Moessbauer line broadening measured by R. LINDSEY in α-iron stabilized with vanadium is evaluated by an exponential fit described in the APPENDIX of this paper. By this procedure the low temperature Moessbauer line width GAMMAsub(m) 0 the diffusion frequency factor D 0 and the activation enthalpy ΔH are computed. KNAUER'S and SOERENSEN-TRUMPY'S definitions of the time correlation factor fsub(t), necessary for the D 0 calculation from Moessbauer line broadening, are applied to the Fe-V diluted BCC solid solutions. (author)

  16. DNAzyme Feedback Amplification: Relaying Molecular Recognition to Exponential DNA Amplification.

    Science.gov (United States)

    Liu, Meng; Yin, Qingxin; McConnell, Erin M; Chang, Yangyang; Brennan, John D; Li, Yingfu

    2018-03-26

    Technologies capable of linking DNA amplification to molecular recognition are very desirable for ultrasensitive biosensing applications. We have developed a simple but powerful isothermal DNA amplification method, termed DNAzyme feedback amplification (DFA), that is capable of relaying molecular recognition to exponential DNA amplification. The method incorporates both an RNA-cleaving DNAzyme (RCD) and rolling circle amplification (RCA) carried out by a special DNA polymerase using a circular DNA template. DFA begins with a stimulus-dependent RCA reaction, producing tandemly linked RCDs in long-chain DNA products. These RCDs cleave an RNA-containing DNA sequence to form additional primers that hybridize to the circular DNA molecule, giving rise to DNA assemblies that act as the new inputs for RCA. The RCA reaction and the cleavage event keep on feeding each other autonomously, resulting in exponential growth of repetitive DNA sequences that can be easily detected. This method can be used for the detection of both nucleic acid based targets and non-nucleic acid analytes. In this article, we discuss the conceptual framework of the feedback amplification approach, the essential features of this method as well as remaining challenges and possible solutions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Application of heterogeneous method for the interpretation of exponential experiments

    International Nuclear Information System (INIS)

    Birkhoff, G.; Bondar, L.

    1977-01-01

    The present paper gives a brief review of a work which was executed mainly during 1967 and 1968 in the field of the application of heterogeneous methods for the interpretation of exponential experiments with ORGEL type lattices (lattices of natural uranium cluster elements with organic coolants moderated by heavy water). In the frame of this work a heterogeneous computer program, in (r,γ) geometry was written which is based on the NORDHEIM method using a uniform moderator, three energy groups and monopol and dipol sources. This code is especially adapted for regular square lattices in a cylindrical tank. Full use of lattice symmetry was made for reducing the numerical job of the theory. A further reduction was obtained by introducing a group averaged extrapolation distance at the external boundary. Channel parameters were evaluated by the PINOCCHIO code. Comparisons of calculated and measured thermal neutron flux showed good agreement. Equivalence of heterogeneous and homogeneous theory was found in cases of lattices comprising a minimum of 32, 24 and 16 fuel elements for respectively under-, well-, and over-moderated lattices. Heterogeneous calculations of high leakage lattices suffered the lack of good methods for the computation of axial and radial streaming parameters. Interpretation of buckling measurements in the subcritical facility EXPO requires already more accurate evaluation of the streaming effects than we made. The potential of heterogeneous theory in the field of exponential experiments is thought to be limited by the precision by which the streaming parameters can be calculated

  18. Data assimilation on the exponentially accurate slow manifold.

    Science.gov (United States)

    Cotter, Colin

    2013-05-28

    I describe an approach to data assimilation making use of an explicit map that defines a coordinate system on the slow manifold in the semi-geostrophic scaling in Lagrangian coordinates, and apply the approach to a simple toy system that has previously been proposed as a low-dimensional model for the semi-geostrophic scaling. The method can be extended to Lagrangian particle methods such as Hamiltonian particle-mesh and smooth-particle hydrodynamics applied to the rotating shallow-water equations, and many of the properties will remain for more general Eulerian methods. Making use of Hamiltonian normal-form theory, it has previously been shown that, if initial conditions for the system are chosen as image points of the map, then the fast components of the system have exponentially small magnitude for exponentially long times as ε→0, and this property is preserved if one uses a symplectic integrator for the numerical time stepping. The map may then be used to parametrize initial conditions near the slow manifold, allowing data assimilation to be performed without introducing any fast degrees of motion (more generally, the precise amount of fast motion can be selected).

  19. Comparison of matrix exponential methods for fuel burnup calculations

    International Nuclear Information System (INIS)

    Oh, Hyung Suk; Yang, Won Sik

    1999-01-01

    Series expansion methods to compute the exponential of a matrix have been compared by applying them to fuel depletion calculations. Specifically, Taylor, Pade, Chebyshev, and rational Chebyshev approximations have been investigated by approximating the exponentials of bum matrices by truncated series of each method with the scaling and squaring algorithm. The accuracy and efficiency of these methods have been tested by performing various numerical tests using one thermal reactor and two fast reactor depletion problems. The results indicate that all the four series methods are accurate enough to be used for fuel depletion calculations although the rational Chebyshev approximation is relatively less accurate. They also show that the rational approximations are more efficient than the polynomial approximations. Considering the computational accuracy and efficiency, the Pade approximation appears to be better than the other methods. Its accuracy is better than the rational Chebyshev approximation, while being comparable to the polynomial approximations. On the other hand, its efficiency is better than the polynomial approximations and is similar to the rational Chebyshev approximation. In particular, for fast reactor depletion calculations, it is faster than the polynomial approximations by a factor of ∼ 1.7. (author). 11 refs., 4 figs., 2 tabs

  20. Three-Step Predictor-Corrector of Exponential Fitting Method for Nonlinear Schroedinger Equations

    International Nuclear Information System (INIS)

    Tang Chen; Zhang Fang; Yan Haiqing; Luo Tao; Chen Zhanqing

    2005-01-01

    We develop the three-step explicit and implicit schemes of exponential fitting methods. We use the three-step explicit exponential fitting scheme to predict an approximation, then use the three-step implicit exponential fitting scheme to correct this prediction. This combination is called the three-step predictor-corrector of exponential fitting method. The three-step predictor-corrector of exponential fitting method is applied to numerically compute the coupled nonlinear Schroedinger equation and the nonlinear Schroedinger equation with varying coefficients. The numerical results show that the scheme is highly accurate.

  1. Hausdorff dimension of exponential parameter rays and their endpoints

    International Nuclear Information System (INIS)

    Bailesteanu, Mihai; Balan, Horia Vlad; Schleicher, Dierk

    2008-01-01

    We investigate the set I of parameters κ for which the singular value of z map e z + κ converges to ∞. The set I consists of uncountably many parameter rays, plus landing points of some of these rays (Förster et al 2008 Proc Am. Math. Soc. 136 at press (Preprint math.DS/0311427)). We show that the parameter rays have Hausdorff dimension 1, which implies (Qiu 1994 Acta Math. Sin. (N.S.) 10 362–8) that the ray endpoints in I alone have dimension 2. Analogous results were known for dynamical planes of exponential maps (Karpińska 1999 C. R. Acad. Sci. Paris Sér. I: Math. 328 1039–44; Schleicher and Zimmer 2003 J. Lond. Math. Soc. 67 380–400); our result shows that this also holds in parameter space

  2. A Generalization of Exponential Class and Its Applications

    Directory of Open Access Journals (Sweden)

    Hongya Gao

    2013-01-01

    Full Text Available A function space, Lθ,∞(Ω, 0≤θ<∞, is defined. It is proved that Lθ,∞(Ω is a Banach space which is a generalization of exponential class. An alternative definition of Lθ,∞(Ω space is given. As an application, we obtain weak monotonicity property for very weak solutions of -harmonic equation with variable coefficients under some suitable conditions related to Lθ,∞(Ω, which provides a generalization of a known result due to Moscariello. A weighted space Lwθ,∞(Ω is also defined, and the boundedness for the Hardy-Littlewood maximal operator Mw and a Calderón-Zygmund operator T with respect to Lwθ,∞(Ω is obtained.

  3. Academia-industry collaboration feeds exponential growth curve

    CERN Document Server

    Jones Bey Hassaun, A

    2004-01-01

    The use of silicon strip detectors in high-energy particle tracking is discussed. The functional strength of silicon for high-energy particle physics as well as astrophysics lies in the ability to detect passage of charged particles with micron-scale spatial resolution. In addition to vertex detection, silicon strip detectors also provide full tracking detection to include momentum determination of particles in the magnetic field. Even if silicon detectors for basic science applications do not continue to grow larger, exponential growth of the technology for terrestrial commercial applications is likely to follow a healthy growth curve, as researchers continue to adapt silicon detector technology for low- dose medical x-ray imaging. (Edited abstract)

  4. Day-Ahead Load Forecasting Using Exponential Smoothing

    Directory of Open Access Journals (Sweden)

    R. Bindiu

    2009-12-01

    Full Text Available The existence of a liberated market for electricity implies the necessity of using load forecasting in order to optimize and reduce the costs for the electric energy consumption. Different strategies for the purchase of electrical energy require precise load forecasting. The Day Ahead Market makes possible the acquisition of electricity for one day in advance. This reduces the risk of making electrical energy transactions on Balance Market, which means buying at a very high price and selling at a very low price. This paper presents a Day Ahead Load Forecasting approach for an industrial costumer using exponential smoothing method. The purpose of this paper is to present a new method for day ahead load forecasting.

  5. Hyponormal quantization of planar domains exponential transform in dimension two

    CERN Document Server

    Gustafsson, Björn

    2017-01-01

    This book exploits the classification of a class of linear bounded operators with rank-one self-commutators in terms of their spectral parameter, known as the principal function. The resulting dictionary between two dimensional planar shapes with a degree of shade and Hilbert space operators turns out to be illuminating and beneficial for both sides. An exponential transform, essentially a Riesz potential at critical exponent, is at the heart of this novel framework; its best rational approximants unveil a new class of complex orthogonal polynomials whose asymptotic distribution of zeros is thoroughly studied in the text. Connections with areas of potential theory, approximation theory in the complex domain and fluid mechanics are established. The text is addressed, with specific aims, at experts and beginners in a wide range of areas of current interest: potential theory, numerical linear algebra, operator theory, inverse problems, image and signal processing, approximation theory, mathematical physics.

  6. On Using Exponential Parameter Estimators with an Adaptive Controller

    Science.gov (United States)

    Patre, Parag; Joshi, Suresh M.

    2011-01-01

    Typical adaptive controllers are restricted to using a specific update law to generate parameter estimates. This paper investigates the possibility of using any exponential parameter estimator with an adaptive controller such that the system tracks a desired trajectory. The goal is to provide flexibility in choosing any update law suitable for a given application. The development relies on a previously developed concept of controller/update law modularity in the adaptive control literature, and the use of a converse Lyapunov-like theorem. Stability analysis is presented to derive gain conditions under which this is possible, and inferences are made about the tracking error performance. The development is based on a class of Euler-Lagrange systems that are used to model various engineering systems including space robots and manipulators.

  7. Thermal dynamics on the lattice with exponentially improved accuracy

    Science.gov (United States)

    Pawlowski, Jan M.; Rothkopf, Alexander

    2018-03-01

    We present a novel simulation prescription for thermal quantum fields on a lattice that operates directly in imaginary frequency space. By distinguishing initial conditions from quantum dynamics it provides access to correlation functions also outside of the conventional Matsubara frequencies ωn = 2 πnT. In particular it resolves their frequency dependence between ω = 0 and ω1 = 2 πT, where the thermal physics ω ∼ T of e.g. transport phenomena is dominantly encoded. Real-time spectral functions are related to these correlators via an integral transform with rational kernel, so that their unfolding from the novel simulation data is exponentially improved compared to standard Euclidean simulations. We demonstrate this improvement within a non-trivial 0 + 1-dimensional quantum mechanical toy-model and show that spectral features inaccessible in standard Euclidean simulations are quantitatively captured.

  8. Exponential Lower Bounds for the PPSZ k-SAT Algorithm

    DEFF Research Database (Denmark)

    Chen, Shiteng; Scheder, Dominik Alban; Talebanfard, Navid

    2013-01-01

    In 1998, Paturi, Pudl´ak, Saks, and Zane presented PPSZ, an elegant randomized algorithm for k-SAT. Fourteen years on, this algorithm is still the fastest known worst-case algorithm. They proved that its expected running time on k-CNF formulas with n variables is at most 2(1−k)n, where k 2 (1/k).......). So far, no exponential lower bounds at all have been known. In this paper, we construct hard instances for PPSZ. That is, we construct satisfiable k-CNF formulas over n variables on which the expected running time is at least 2(1−k)n, for k 2 O(log2 k/k)....

  9. Vacuum heating evaluation for plasmas of exponentially decreasing density profile

    International Nuclear Information System (INIS)

    Pestehe, S.J.; Mohammadnejad, M.

    2008-01-01

    Ultra-short pulse lasers have opened a regime of laser-plasma interaction where plasmas have scale lengths shorter than the laser wavelength and allow the possibility of generating near-solid density plasmas. The interaction of high-intensity laser beams with sharply bounded high-density and small scale length plasmas is considered. Absorption of the laser energy associated with the mechanism of dragging electrons out of the plasma into the vacuum and sending them back into the plasma with the electric field component along the density gradient, so called vacuum heating, is studied. An exponentially decreasing electron density profile is assumed. The vector potential of the electromagnetic field propagating through the plasma is calculated and the behaviour of the electric and magnetic components of the electromagnetic field is studied. The fraction of laser power absorbed in this process is calculated and plotted versus the laser beam incidence angle, illumination energy, and the plasma scale length

  10. The SIS process in populations with exponential decay

    Science.gov (United States)

    Barankai, Norbert; Stéger, József

    2018-01-01

    We study the final state of a susceptible-infected-susceptible (SIS) process whose running time is an exponentially distributed random variable. The population in which the spreading evolves is assumed to be homogeneously mixed. We show that whenever the state dependent normalized infection rates are on average smaller than the corresponding curing rates, the final prevalence of the process vanishes in the large population size limit, irrespectively of the mean running time of the process. We show how this statement implies similar results concerning the time evolution of the SIS and the modified SIS processes as well as the steady state of the modified SIS process. In the case of the usual SIS model, for suitably low values of the mean running time, the absence of a non-vanishing prevalence is found in the large population size limit, even if the normalized infection rate exceeds the curing rate.

  11. arXiv Exponentially Light Dark Matter from Coannihilation

    CERN Document Server

    D'Agnolo, Raffaele Tito; Ruderman, Joshua T.; Wang, Po-Jen

    Dark matter may be a thermal relic whose abundance is set by mutual annihilations among multiple species. Traditionally, this coannihilation scenario has been applied to weak scale dark matter that is highly degenerate with other states. We show that coannihilation among states with split masses points to dark matter that is exponentially lighter than the weak scale, down to the keV scale. We highlight the regime where dark matter does not participate in the annihilations that dilute its number density. In this "sterile coannihilation" limit, the dark matter relic density is independent of its couplings, implying a broad parameter space of thermal relic targets for future experiments. Light dark matter from coannihilation evades stringent bounds from the cosmic microwave background, but will be tested by future direct detection, fixed target, and long-lived particle experiments.

  12. Mathematics of thermal diffusion in an exponential temperature field

    Science.gov (United States)

    Zhang, Yaqi; Bai, Wenyu; Diebold, Gerald J.

    2018-04-01

    The Ludwig-Soret effect, also known as thermal diffusion, refers to the separation of gas, liquid, or solid mixtures in a temperature gradient. The motion of the components of the mixture is governed by a nonlinear, partial differential equation for the density fractions. Here solutions to the nonlinear differential equation for a binary mixture are discussed for an externally imposed, exponential temperature field. The equation of motion for the separation without the effects of mass diffusion is reduced to a Hamiltonian pair from which spatial distributions of the components of the mixture are found. Analytical calculations with boundary effects included show shock formation. The results of numerical calculations of the equation of motion that include both thermal and mass diffusion are given.

  13. Winning Concurrent Reachability Games Requires Doubly-Exponential Patience

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Koucký, Michal; Miltersen, Peter Bro

    2009-01-01

    We exhibit a deterministic concurrent reachability game PURGATORYn with n non-terminal positions and a binary choice for both players in every position so that any positional strategy for Player 1 achieving the value of the game within given isin ... that are less than (isin2/(1 - isin))2n-2 . Also, even to achieve the value within say 1 - 2-n/2, doubly exponentially small behavior probabilities in the number of positions must be used. This behavior is close to worst case: We show that for any such game and 0 strategy...... with all non-zero behavior probabilities being 20(n) at least isin2O(n). As a corollary to our results, we conclude that any (deterministic or nondeterministic) algorithm that given a concurrent reachability game explicitly manipulates isin-optimal strategies for Player 1 represented in several standard...

  14. Closed-Form Expressions for the Matrix Exponential

    Directory of Open Access Journals (Sweden)

    F. De Zela

    2014-04-01

    Full Text Available We discuss a method to obtain closed-form expressions of f(A, where f is an analytic function and A a square, diagonalizable matrix. The method exploits the Cayley–Hamilton theorem and has been previously reported using tools that are perhaps not sufficiently appealing to physicists. Here, we derive the results on which the method is based by using tools most commonly employed by physicists. We show the advantages of the method in comparison with standard approaches, especially when dealing with the exponential of low-dimensional matrices. In contrast to other approaches that require, e.g., solving differential equations, the present method only requires the construction of the inverse of the Vandermonde matrix. We show the advantages of the method by applying it to different cases, mostly restricting the calculational effort to the handling of two-by-two matrices.

  15. Galilean invariance in the exponential model of atomic collisions

    Energy Technology Data Exchange (ETDEWEB)

    del Pozo, A.; Riera, A.; Yaez, M.

    1986-11-01

    Using the X/sup n//sup +/(1s/sup 2/)+He/sup 2+/ colliding systems as specific examples, we study the origin dependence of results in the application of the two-state exponential model, and we show the relevance of polarization effects in that study. Our analysis shows that polarization effects of the He/sup +/(1s) orbital due to interaction with X/sup (//sup n//sup +1)+/ ion in the exit channel yield a very small contribution to the energy difference and render the dynamical coupling so strongly origin dependent that it invalidates the basic premises of the model. Further study, incorporating translation factors in the formalism, is needed.

  16. Predicting jet radius in electrospinning by superpositioning exponential functions

    International Nuclear Information System (INIS)

    Widartiningsih, P M; Viridi, S; Iskandar, F; Munir, M M

    2016-01-01

    This paper presents an analytical study of the correlation between viscosity and fiber diameter in electrospinning. Control over fiber diameter in electrospinning process was important since it will determine the performance of resulting nanofiber. Theoretically, fiber diameter was determined by surface tension, solution concentration, flow rate, and electric current. But experimentally it had been proven that significantly viscosity had an influence to fiber diameter. Jet radius equation in electrospinning process was divided into three areas: near the nozzle, far from the nozzle, and at jet terminal. There was no correlation between these equations. Superposition of exponential series model provides the equations combined into one, thus the entire of working parameters on electrospinning take a contribution to fiber diameter. This method yields the value of solution viscosity has a linear relation to jet radius. However, this method works only for low viscosity. (paper)

  17. An exponential integrator for the drift-kinetic model

    Science.gov (United States)

    Crouseilles, Nicolas; Einkemmer, Lukas; Prugger, Martina

    2018-03-01

    We propose an exponential integrator for the drift-kinetic equation in cylindrical geometry. This approach removes the CFL condition from the linear part of the system (which is often the most stringent requirement in practice) and treats the remainder explicitly using Arakawa's finite difference scheme. The present approach is mass conservative, up to machine precision, and significantly reduces the computational effort per time step. In addition, we demonstrate the efficiency of our method by performing numerical simulations in the context of the ion temperature gradient instability. In particular, we find that our numerical method can take time steps comparable to what has been reported in the literature for the (predominantly used) splitting approach. In addition, the proposed numerical method has significant advantages with respect to conservation of energy and efficient higher order methods can be obtained easily. We demonstrate this by investigating the performance of a fourth order implementation.

  18. Two families of astrophysical diverging lens models

    Science.gov (United States)

    Er, Xinzhong; Rogers, Adam

    2018-03-01

    In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

  19. The impact of accelerating faster than exponential population growth on genetic variation.

    Science.gov (United States)

    Reppell, Mark; Boehnke, Michael; Zöllner, Sebastian

    2014-03-01

    Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models' effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times.

  20. Mean Excess Function as a method of identifying sub-exponential tails: Application to extreme daily rainfall

    Science.gov (United States)

    Nerantzaki, Sofia; Papalexiou, Simon Michael

    2017-04-01

    Identifying precisely the distribution tail of a geophysical variable is tough, or, even impossible. First, the tail is the part of the distribution for which we have the less empirical information available; second, a universally accepted definition of tail does not and cannot exist; and third, a tail may change over time due to long-term changes. Unfortunately, the tail is the most important part of the distribution as it dictates the estimates of exceedance probabilities or return periods. Fortunately, based on their tail behavior, probability distributions can be generally categorized into two major families, i.e., sub-exponentials (heavy-tailed) and hyper-exponentials (light-tailed). This study aims to update the Mean Excess Function (MEF), providing a useful tool in order to asses which type of tail better describes empirical data. The MEF is based on the mean value of a variable over a threshold and results in a zero slope regression line when applied for the Exponential distribution. Here, we construct slope confidence intervals for the Exponential distribution as functions of sample size. The validation of the method using Monte Carlo techniques on four theoretical distributions covering major tail cases (Pareto type II, Log-normal, Weibull and Gamma) revealed that it performs well especially for large samples. Finally, the method is used to investigate the behavior of daily rainfall extremes; thousands of rainfall records were examined, from all over the world and with sample size over 100 years, revealing that heavy-tailed distributions can describe more accurately rainfall extremes.

  1. Exponential model normalization for electrical capacitance tomography with external electrodes under gap permittivity conditions

    International Nuclear Information System (INIS)

    Baidillah, Marlin R; Takei, Masahiro

    2017-01-01

    A nonlinear normalization model which is called exponential model for electrical capacitance tomography (ECT) with external electrodes under gap permittivity conditions has been developed. The exponential model normalization is proposed based on the inherently nonlinear relationship characteristic between the mixture permittivity and the measured capacitance due to the gap permittivity of inner wall. The parameters of exponential equation are derived by using an exponential fitting curve based on the simulation and a scaling function is added to adjust the experiment system condition. The exponential model normalization was applied to two dimensional low and high contrast dielectric distribution phantoms by using simulation and experimental studies. The proposed normalization model has been compared with other normalization models i.e. Parallel, Series, Maxwell and Böttcher models. Based on the comparison of image reconstruction results, the exponential model is reliable to predict the nonlinear normalization of measured capacitance in term of low and high contrast dielectric distribution. (paper)

  2. Convergence and stability of the exponential Euler method for semi-linear stochastic delay differential equations.

    Science.gov (United States)

    Zhang, Ling

    2017-01-01

    The main purpose of this paper is to investigate the strong convergence and exponential stability in mean square of the exponential Euler method to semi-linear stochastic delay differential equations (SLSDDEs). It is proved that the exponential Euler approximation solution converges to the analytic solution with the strong order [Formula: see text] to SLSDDEs. On the one hand, the classical stability theorem to SLSDDEs is given by the Lyapunov functions. However, in this paper we study the exponential stability in mean square of the exact solution to SLSDDEs by using the definition of logarithmic norm. On the other hand, the implicit Euler scheme to SLSDDEs is known to be exponentially stable in mean square for any step size. However, in this article we propose an explicit method to show that the exponential Euler method to SLSDDEs is proved to share the same stability for any step size by the property of logarithmic norm.

  3. Cyanide-insensitive respiration in Acanthamoeba castellanii. Changes in sensitivity of whole cell respiration during exponential growth

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, S.W.; Lloyd, D.

    1977-01-01

    Respiration of Acanthamoeba castellanii shows varying sensitivity to cyanide during exponential growth in a medium containing proteose peptone, glucose and yeast extract. After 20 h growth, respiration was stimulated up to 40% by I mM-cyanide; sensitivity to cyanide then gradually increased until 90% inhibition of respiration was attained in late exponential phase cultures. Salicyl hydroxamic acid alone never stimulated or inhibited respiration by more than 20% but, when added together with cyanide, inhibition was always 70 to 100% from 3 h onward. Sensitivity to antimycin A was similar, but not identical to that shown to cyanide; when antimycin A was added together with salicyl hydroxamic acid, the inhibition was greater. Increased sensitivities to arsenite and malonate were also observed in late-exponential phase cultures. These changes in sensitivities were not associated with alterations in the growth medium since similar changes in sensitivity to inhibitors were observed during growth in conditioned medium. A rotenone-sensitive site is associated with cyanide-stimulated respiration and the results suggest that A. castellanii possesses a branched electron transport system.

  4. Using of exponential integrals for atomic nucleus: Pt. 1

    International Nuclear Information System (INIS)

    Marinchev, E.; Karastoyanov, A.

    1986-01-01

    A possibility for direct calculation of the potential of homogenous spherical nucleus using exponential integrals is found. The-two particle static Laplace potential is U=-gE 2 (μr)/4πr, where g is the nuclear charge, μ is a constant and r is the distance between the nucleons. The potential and force curves for a nucleus with the radius R for μr=3,4,5,6,7 are shown. The saturation of the nuclear forces is demonstrated. The limit potential depth is U m =-42.2 MeV for R=1.36 A 1/3 fm, where A is the atomic number. The limit potential at the end of the nucleus is twice as small. A comparison is made with the Yukawa potential, which gives a limit depth triple as large, and with the Woods-Saxon potential, which gives the force in the nuclear centre not equal to zero. The formulae and method are also applicable for more complicated nucleon distributions. (author). 4 figs, 9 refs

  5. A Study on The Mixture of Exponentiated-Weibull Distribution

    Directory of Open Access Journals (Sweden)

    Adel Tawfik Elshahat

    2016-12-01

    Full Text Available Mixtures of measures or distributions occur frequently in the theory and applications of probability and statistics. In the simplest case it may, for example, be reasonable to assume that one is dealing with the mixture in given proportions of a finite number of normal populations with different means or variances. The mixture parameter may also be denumerable infinite, as in the theory of sums of a random number of random variables, or continuous, as in the compound Poisson distribution. The use of finite mixture distributions, to control for unobserved heterogeneity, has become increasingly popular among those estimating dynamic discrete choice models. One of the barriers to using mixture models is that parameters that could previously be estimated in stages must now be estimated jointly: using mixture distributions destroys any additive reparability of the log likelihood function. In this thesis, the maximum likelihood estimators have been obtained for the parameters of the mixture of exponentiated Weibull distribution when sample is available from censoring scheme. The maximum likelihood estimators of the parameters and the asymptotic variance covariance matrix have been also obtained. A numerical illustration for these new results is given.

  6. An Exponentially Weighted Moving Average Control Chart for Bernoulli Data

    DEFF Research Database (Denmark)

    Spliid, Henrik

    2010-01-01

    We consider a production process in which units are produced in a sequential manner. The units can, for example, be manufactured items or services, provided to clients. Each unit produced can be a failure with probability p or a success (non-failure) with probability (1-p). A novel exponentially ...... weighted moving average (EWMA) control chart intended for surveillance of the probability of failure, p, is described. The chart is based on counting the number of non-failures produced between failures in combination with a variance-stabilizing transformation. The distribution function...... of the transformation is given and its limit for small values of p is derived. Control of high yield processes is discussed and the chart is shown to perform very well in comparison with both the most common alternative EWMA chart and the CUSUM chart. The construction and the use of the proposed EWMA chart...... are described and a practical example is given. It is demonstrated how the method communicates the current failure probability in a direct and interpretable way, which makes it well suited for surveillance of a great variety of activities in industry or in the service sector such as in hospitals, for example...

  7. Asymmetric Bimodal Exponential Power Distribution on the Real Line

    Directory of Open Access Journals (Sweden)

    Mehmet Niyazi Çankaya

    2018-01-01

    Full Text Available The asymmetric bimodal exponential power (ABEP distribution is an extension of the generalized gamma distribution to the real line via adding two parameters that fit the shape of peakedness in bimodality on the real line. The special values of peakedness parameters of the distribution are a combination of half Laplace and half normal distributions on the real line. The distribution has two parameters fitting the height of bimodality, so capacity of bimodality is enhanced by using these parameters. Adding a skewness parameter is considered to model asymmetry in data. The location-scale form of this distribution is proposed. The Fisher information matrix of these parameters in ABEP is obtained explicitly. Properties of ABEP are examined. Real data examples are given to illustrate the modelling capacity of ABEP. The replicated artificial data from maximum likelihood estimates of parameters of ABEP and other distributions having an algorithm for artificial data generation procedure are provided to test the similarity with real data. A brief simulation study is presented.

  8. Exponential 6 parameterization for the JCZ3-EOS

    Energy Technology Data Exchange (ETDEWEB)

    McGee, B.C.; Hobbs, M.L.; Baer, M.R.

    1998-07-01

    A database has been created for use with the Jacobs-Cowperthwaite-Zwisler-3 equation-of-state (JCZ3-EOS) to determine thermochemical equilibrium for detonation and expansion states of energetic materials. The JCZ3-EOS uses the exponential 6 intermolecular potential function to describe interactions between molecules. All product species are characterized by r*, the radius of the minimum pair potential energy, and {var_epsilon}/k, the well depth energy normalized by Boltzmann`s constant. These parameters constitute the JCZS (S for Sandia) EOS database describing 750 gases (including all the gases in the JANNAF tables), and have been obtained by using Lennard-Jones potential parameters, a corresponding states theory, pure liquid shock Hugoniot data, and fit values using an empirical EOS. This database can be used with the CHEETAH 1.40 or CHEETAH 2.0 interface to the TIGER computer program that predicts the equilibrium state of gas- and condensed-phase product species. The large JCZS-EOS database permits intermolecular potential based equilibrium calculations of energetic materials with complex elemental composition.

  9. Predictors of the peak width for networks with exponential links

    Science.gov (United States)

    Troutman, B.M.; Karlinger, M.R.

    1989-01-01

    We investigate optimal predictors of the peak (S) and distance to peak (T) of the width function of drainage networks under the assumption that the networks are topologically random with independent and exponentially distributed link lengths. Analytical results are derived using the fact that, under these assumptions, the width function is a homogeneous Markov birth-death process. In particular, exact expressions are derived for the asymptotic conditional expectations of S and T given network magnitude N and given mainstream length H. In addition, a simulation study is performed to examine various predictors of S and T, including N, H, and basin morphometric properties; non-asymptotic conditional expectations and variances are estimated. The best single predictor of S is N, of T is H, and of the scaled peak (S divided by the area under the width function) is H. Finally, expressions tested on a set of drainage basins from the state of Wyoming perform reasonably well in predicting S and T despite probable violations of the original assumptions. ?? 1989 Springer-Verlag.

  10. Exponential local discriminant embedding and its application to face recognition.

    Science.gov (United States)

    Dornaika, Fadi; Bosaghzadeh, Alireza

    2013-06-01

    Local discriminant embedding (LDE) has been recently proposed to overcome some limitations of the global linear discriminant analysis method. In the case of a small training data set, however, LDE cannot directly be applied to high-dimensional data. This case is the so-called small-sample-size (SSS) problem. The classical solution to this problem was applying dimensionality reduction on the raw data (e.g., using principal component analysis). In this paper, we introduce a novel discriminant technique called "exponential LDE" (ELDE). The proposed ELDE can be seen as an extension of LDE framework in two directions. First, the proposed framework overcomes the SSS problem without discarding the discriminant information that was contained in the null space of the locality preserving scatter matrices associated with LDE. Second, the proposed ELDE is equivalent to transforming original data into a new space by distance diffusion mapping (similar to kernel-based nonlinear mapping), and then, LDE is applied in such a new space. As a result of diffusion mapping, the margin between samples belonging to different classes is enlarged, which is helpful in improving classification accuracy. The experiments are conducted on five public face databases: Yale, Extended Yale, PF01, Pose, Illumination, and Expression (PIE), and Facial Recognition Technology (FERET). The results show that the performances of the proposed ELDE are better than those of LDE and many state-of-the-art discriminant analysis techniques.

  11. On the role of exponential smoothing in circadian dosimetry.

    Science.gov (United States)

    Price, Luke L A

    2014-01-01

    The effects lighting has on health through modulation of circadian rhythms are becoming increasingly well documented. Data are still needed to show how light exposures are influenced by architecture and lighting design and circadian dosimetry analyses should provide duration, phase and amplitude measures of 24 h exposure profiles. Exponential smoothing is used to derive suitable metrics from 24 h light measurements collected from private dwellings. A further application of these modified exposure time series as physiological models of the light drive is discussed. Unlike previous light drive models, the dose rate persists into periods of darkness following exposures. Comparisons to long duration exposure studies suggest this type of persistent light drive model could be incorporated into contemporary physiological models of the human circadian oscillator. © 2014 Crown copyright. Photochemistry and Photobiology © 2014 The American Society of Photobiology. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland and Public Health England.

  12. The absorption of gamma, gamma-families and hadrons in the atmosphere - EC data

    Energy Technology Data Exchange (ETDEWEB)

    Shaulov, S.B., E-mail: shaul@sci.lebedev.r [P.N.Lebedev physical Institute, FIAN, Leninsky prospect 53, 119991 Moscow (Russian Federation); Cherdyntceva, K.V. [P.N.Lebedev physical Institute, FIAN, Leninsky prospect 53, 119991 Moscow (Russian Federation); Janceitova, J.K. [Tien-Shan Highmountain Station, Mitina 3, Almaty (Kazakhstan)

    2009-12-15

    The energy spectra SIGMAE{sub g}amma, E{sub g}amma for gamma-families and hadrons at the level of the Pamir (600 g/cm{sup 2}) and Tien-Shan (685 g/cm{sup 2}) mountains are compared. The ratio of event intensities permits to observe the absorption lengths for different types of events in X-ray emulsion chambers: single gamma-quanta, hadrons, gamma-families and super-families with halo. These values of lambda{sub att} are much more than those determined from zenith angle distributions. Data from other EC experiments are used to decrease the errors in lambda{sub att}. The absorption curves in the atmosphere were obtained for gamma-families and gamma-quanta by means of data compiled for different EC experiments at balloon, aeroplane and mountain heights. The absorption curves cannot be described as a simple exponential dependence in both cases.

  13. Exponentially long Equilibration times in a 1-D Collisional Model of a classical gas

    DEFF Research Database (Denmark)

    Hjorth, Poul; Benettin, G.

    1999-01-01

    Around the year 1900, J.H. Jeans suggested that the `abnormal' specific heats observed in diatomic gases, specifically the lack of contribution to the heat capacity from the internal vibrational degrees of freedom, in apparent violation of the equipartition theorem, might be caused by the large...... separation between the time scale for the vibration and the time scale associated with a typical binary collision in the gas. We consider here a simple 1-D model, and show how, when these time scales are well separated, the collisional dynamics is constrained by a many-particle adiabatic invariant....... The effect is that the collisional energy exchanges between the translational and the vibrational degrees of freedom are slowed down by an exponential factor (as Jeans conjectured). A metastable situation thus occurs, in which the fast vibrational degrees of freedom effectivly do not contribute...

  14. A new modification in the exponential rational function method for nonlinear fractional differential equations

    Science.gov (United States)

    Ahmed, Naveed; Bibi, Sadaf; Khan, Umar; Mohyud-Din, Syed Tauseef

    2018-02-01

    We have modified the traditional exponential rational function method (ERFM) and have used it to find the exact solutions of two different fractional partial differential equations, one is the time fractional Boussinesq equation and the other is the (2+1)-dimensional time fractional Zoomeron equation. In both the cases it is observed that the modified scheme provides more types of solutions than the traditional one. Moreover, a comparison of the recent solutions is made with some already existing solutions. We can confidently conclude that the modified scheme works better and provides more types of solutions with almost similar computational cost. Our generalized solutions include periodic, soliton-like, singular soliton and kink solutions. A graphical simulation of all types of solutions is provided and the correctness of the solution is verified by direct substitution. The extended version of the solutions is expected to provide more flexibility to scientists working in the relevant field to test their simulation data.

  15. Microarray background correction: maximum likelihood estimation for the normal-exponential convolution

    DEFF Research Database (Denmark)

    Silver, Jeremy D; Ritchie, Matthew E; Smyth, Gordon K

    2009-01-01

    Background correction is an important preprocessing step for microarray data that attempts to adjust the data for the ambient intensity surrounding each feature. The "normexp" method models the observed pixel intensities as the sum of 2 random variables, one normally distributed and the other...... is developed for exact maximum likelihood estimation (MLE) using high-quality optimization software and using the saddle-point estimates as starting values. "MLE" is shown to outperform heuristic estimators proposed by other authors, both in terms of estimation accuracy and in terms of performance on real data...... exponentially distributed, representing background noise and signal, respectively. Using a saddle-point approximation, Ritchie and others (2007) found normexp to be the best background correction method for 2-color microarray data. This article develops the normexp method further by improving the estimation...

  16. Inference for exponentiated general class of distributions based on record values

    Directory of Open Access Journals (Sweden)

    Samah N. Sindi

    2017-09-01

    Full Text Available The main objective of this paper is to suggest and study a new exponentiated general class (EGC of distributions. Maximum likelihood, Bayesian and empirical Bayesian estimators of the parameter of the EGC of distributions based on lower record values are obtained. Furthermore, Bayesian prediction of future records is considered. Based on lower record values, the exponentiated Weibull distribution, its special cases of distributions and exponentiated Gompertz distribution are applied to the EGC of distributions.  

  17. Adaptive Outlier-tolerant Exponential Smoothing Prediction Algorithms with Applications to Predict the Temperature in Spacecraft

    OpenAIRE

    Hu Shaolin; Zhang Wei; Li Ye; Fan Shunxi

    2011-01-01

    The exponential smoothing prediction algorithm is widely used in spaceflight control and in process monitoring as well as in economical prediction. There are two key conundrums which are open: one is about the selective rule of the parameter in the exponential smoothing prediction, and the other is how to improve the bad influence of outliers on prediction. In this paper a new practical outlier-tolerant algorithm is built to select adaptively proper parameter, and the exponential smoothing pr...

  18. On the Ψ-Conditional Exponential Asymptotic Stability of Nonlinear Lyapunov Matrix Differential Equations

    Directory of Open Access Journals (Sweden)

    Diamandescu Aurel

    2016-07-01

    Full Text Available It is proved (necessary and sufficient conditions for Ψ– conditional exponential asymptotic stability of the trivial solution of nonlinear Lyapunov matrix differential equations

  19. What are the physical and psychological health effects of suicide bereavement on family members? Protocol for an observational and interview mixed-methods study in Ireland.

    LENUS (Irish Health Repository)

    Spillane, Ailbhe

    2017-03-30

    Research indicates that experiencing the suicide of a relative can have a significant impact on family members\\' emotional health. However, research incorporating the impact of suicide bereavement on family members\\' physical health is sparse. This paper details the protocol for a mixed-methods study of suicide-bereaved family members. The study will primarily examine the physical and mental health needs of those bereaved by suicide. A secondary objective of the study is to describe the support service needs of family members bereaved by suicide.

  20. Age-severity relationships in families linked to FCD2 with retroillumination photography.

    Science.gov (United States)

    McGlumphy, Elyse J; Yeo, William S; Riazuddin, S Amer; Al-Saif, Amr; Wang, Jiangxia; Eghrari, Allen O; Meadows, Danielle N; Emmert, David G; Katsanis, Nicholas; Gottsch, John D

    2010-12-01

    Fuchs corneal dystrophy (FCD) is a progressive disorder of the corneal endothelium and is pathologically defined by the presence of guttae, which are excrescences of the Descemet membrane. The present study was undertaken to investigate the age-severity relationship of the FCD2-linked disease phenotype using retroillumination photography and to compare it with the characteristics of FCD1. Two large families with multiple affected members were recruited. Exclusion analyses of the known late-onset FCD loci were completed with closely spaced STR markers, whereas genes associated with early- and late-onset FCD were investigated by bidirectional sequencing. Haplotypes were constructed, and two-point LOD scores were calculated. To document age-severity relationships, retroillumination photographs were acquired from members of both families. Parametric linkage and haplotype analysis mapped both families to FCD2 with significant two-point LOD scores. A total of 70,249 guttae were counted in 14 persons from both families. A significant increase in guttae density in the inferotemporal region (P = 0.016) was observed, a pattern similarly observed in a family linked to FCD1. Similarly, FCD2-linked families display an exponential trend in severity with age, as was observed in a family linked to FCD1. Finally, comparison of FCD1 and FCD2 exponential models suggested that the FCD1 phenotype is significantly more severe (P = 0.01). A combination of genetic mapping and retroillumination photography was used to quantify the severity of the disease phenotype associated with FCD2 and to compare it to the disease characteristics of FCD1. These data suggest that this approach might have sufficient resolution to discriminate between discrete genetic FCD backgrounds, which will potentially aid in patient management.

  1. Effects of low dose rate γ-rays on cell proliferation and survival in exponentially growing and plateau phase cultures of normal rat kidney cells

    International Nuclear Information System (INIS)

    Tsuboi, A.

    1982-01-01

    The effects of 60 Co γ-rays on cell clonogenicity and cell proliferation were examined in NRK cells in exponential and plateau growth phases during and after irradiation at various dose rates. The typical dese rate effect for the survival responses was observed between acute irradiation and continuous irradiation at dose rates of 9.6-44 rads/h. Similar dose rate effect for the perturbation of the proliferation was observed in exponentially growing cells during irradiation. Some differences were found in survival when the cells were exposed to γ-rays at 9.6 rads/h or at 13.7 rads/h. The survival curves of exponential phase cells irradiated at these dose rates showed a shape different from that observed in plateau phase cells. Namely, a steady state of survival appeared around an accumulated dose of 1000 rads (dose-rate of 9.6 rads/h) and an accumulated dose of 1500 rads (dose-rate of 13.7 rads/h) in the exponential phase cells, while such a steady state of survival was not detected in plateau phase cells after similar conditions of irradiation. Moreover, the extrapolation number of the survival curve was much larger at the lower dose rate in exponential phase cells, in contrast to a value of the unity oberved in plateau phase cells, The radiosensitivity of plateau phase cells was somewhat lower compared to exponential phase cells over the range of accumulated doses at the dose rates used. These differences in cellular responses to the radiation between the two phases could be explained by changes in cell proliferation, the redistribution of the cell cycle compartments and the repair capacity of cellular damage during irradiation. (author)

  2. Modeling the Lag Period and Exponential Growth of Listeria monocytogenes under Conditions of Fluctuating Temperature and Water Activity Values▿

    Science.gov (United States)

    Muñoz-Cuevas, Marina; Fernández, Pablo S.; George, Susan; Pin, Carmen

    2010-01-01

    The dynamic model for the growth of a bacterial population described by Baranyi and Roberts (J. Baranyi and T. A. Roberts, Int. J. Food Microbiol. 23:277-294, 1994) was applied to model the lag period and exponential growth of Listeria monocytogenes under conditions of fluctuating temperature and water activity (aw) values. To model the duration of the lag phase, the dependence of the parameter h0, which quantifies the amount of work done during the lag period, on the previous and current environmental conditions was determined experimentally. This parameter depended not only on the magnitude of the change between the previous and current environmental conditions but also on the current growth conditions. In an exponentially growing population, any change in the environment requiring a certain amount of work to adapt to the new conditions initiated a lag period that lasted until that work was finished. Observations for several scenarios in which exponential growth was halted by a sudden change in the temperature and/or aw were in good agreement with predictions. When a population already in a lag period was subjected to environmental fluctuations, the system was reset with a new lag phase. The work to be done during the new lag phase was estimated to be the workload due to the environmental change plus the unfinished workload from the uncompleted previous lag phase. PMID:20208022

  3. Modeling the lag period and exponential growth of Listeria monocytogenes under conditions of fluctuating temperature and water activity values.

    Science.gov (United States)

    Muñoz-Cuevas, Marina; Fernández, Pablo S; George, Susan; Pin, Carmen

    2010-05-01

    The dynamic model for the growth of a bacterial population described by Baranyi and Roberts (J. Baranyi and T. A. Roberts, Int. J. Food Microbiol. 23:277-294, 1994) was applied to model the lag period and exponential growth of Listeria monocytogenes under conditions of fluctuating temperature and water activity (a(w)) values. To model the duration of the lag phase, the dependence of the parameter h(0), which quantifies the amount of work done during the lag period, on the previous and current environmental conditions was determined experimentally. This parameter depended not only on the magnitude of the change between the previous and current environmental conditions but also on the current growth conditions. In an exponentially growing population, any change in the environment requiring a certain amount of work to adapt to the new conditions initiated a lag period that lasted until that work was finished. Observations for several scenarios in which exponential growth was halted by a sudden change in the temperature and/or a(w) were in good agreement with predictions. When a population already in a lag period was subjected to environmental fluctuations, the system was reset with a new lag phase. The work to be done during the new lag phase was estimated to be the workload due to the environmental change plus the unfinished workload from the uncompleted previous lag phase.

  4. The distance-decay function of geographical gravity model: Power law or exponential law?

    International Nuclear Information System (INIS)

    Chen, Yanguang

    2015-01-01

    Highlights: •The distance-decay exponent of the gravity model is a fractal dimension. •Entropy maximization accounts for the gravity model based on power law decay. •Allometric scaling relations relate gravity models with spatial interaction models. •The four-parameter gravity models have dual mathematical expressions. •The inverse power law is the most probable distance-decay function. -- Abstract: The distance-decay function of the geographical gravity model is originally an inverse power law, which suggests a scaling process in spatial interaction. However, the distance exponent of the model cannot be reasonably explained with the ideas from Euclidean geometry. This results in a dimension dilemma in geographical analysis. Consequently, a negative exponential function was used to replace the inverse power function to serve for a distance-decay function. But a new puzzle arose that the exponential-based gravity model goes against the first law of geography. This paper is devoted for solving these kinds of problems by mathematical reasoning and empirical analysis. New findings are as follows. First, the distance exponent of the gravity model is demonstrated to be a fractal dimension using the geometric measure relation. Second, the similarities and differences between the gravity models and spatial interaction models are revealed using allometric relations. Third, a four-parameter gravity model possesses a symmetrical expression, and we need dual gravity models to describe spatial flows. The observational data of China's cities and regions (29 elements indicative of 841 data points) in 2010 are employed to verify the theoretical inferences. A conclusion can be reached that the geographical gravity model based on power-law decay is more suitable for analyzing large, complex, and scale-free regional and urban systems. This study lends further support to the suggestion that the underlying rationale of fractal structure is entropy maximization. Moreover

  5. An application of Hansen Exponential Approximation method for the solution of point reactor kinetic equations

    International Nuclear Information System (INIS)

    Paixao, S.B.

    1987-01-01

    In order to find out the numerical solutions of point reactor kinetic, the exponential approximation method is used. The basic assumption is: the neutron populations and delayed precursors behave exponentially with an asymptotic characteristic frequency corresponding to the reactivity. The CIPOR (Point Kinetc with Feedback) computer code was elaborated, and several cases were implemented. (M.C.K.) [pt

  6. A method for searching the possible deviations from exponential decay law

    International Nuclear Information System (INIS)

    Tran Dai Nghiep; Vu Hoang Lam; Tran Vien Ha

    1993-01-01

    A continuous kinetic function approach is proposed for analyzing the experimental decay curves. In the case of purely exponential behaviour, the values of kinetic function are the same at different ages of the investigated radionuclide. The deviation from main decay curve could be found by a comparison of experimental kinetic function values with those obtained in purely exponential case. (author). 12 refs

  7. Delay-dependent exponential stability of cellular neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Zhang Qiang; Wei Xiaopeng; Xu Jin

    2005-01-01

    The global exponential stability of cellular neural networks (CNNs) with time-varying delays is analyzed. Two new sufficient conditions ensuring global exponential stability for delayed CNNs are obtained. The conditions presented here are related to the size of delay. The stability results improve the earlier publications. Two examples are given to demonstrate the effectiveness of the obtained results

  8. Necessary and Sufficient Condition for Local Exponential Synchronization of Nonlinear Systems

    NARCIS (Netherlands)

    Andrieu, Vincent; Jayawardhana, Bayu; Tarbouriech, Sophie

    2015-01-01

    Based on recent works on transverse exponential stability, some necessary and sufficient conditions for the existence of a (locally) exponential synchronizer are established. We show that the existence of a structured synchronizer is equivalent to the existence of a stabilizer for the individual

  9. Method for numerical simulation of two-term exponentially correlated colored noise

    International Nuclear Information System (INIS)

    Yilmaz, B.; Ayik, S.; Abe, Y.; Gokalp, A.; Yilmaz, O.

    2006-01-01

    A method for numerical simulation of two-term exponentially correlated colored noise is proposed. The method is an extension of traditional method for one-term exponentially correlated colored noise. The validity of the algorithm is tested by comparing numerical simulations with analytical results in two physical applications

  10. Exponential decay rate of the power spectrum for solutions of the Navier--Stokes equations

    International Nuclear Information System (INIS)

    Doering, C.R.; Titi, E.S.

    1995-01-01

    Using a method developed by Foias and Temam [J. Funct. Anal. 87, 359 (1989)], exponential decay of the spatial Fourier power spectrum for solutions of the incompressible Navier--Stokes equations is established and explicit rigorous lower bounds on a small length scale defined by the exponential decay rate are obtained

  11. Exponential stability of nonlinear time-varying differential equations and applications

    Directory of Open Access Journals (Sweden)

    N. M. Linh

    2001-05-01

    Full Text Available In this paper, we give sufficient conditions for the exponential stability of a class of nonlinear time-varying differential equations. We use the Lyapunov method with functions that are not necessarily differentiable; hence we extend previous results. We also provide an application to exponential stability for nonlinear time-varying control systems.

  12. On the Construction of Bivariate Exponential Distributions with an Arbitrary Correlation Coefficient

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    2010-01-01

    In this article we use the concept of multivariate phase-type distributions to define a class of bivariate exponential distributions. This class has the following three appealing properties. Firstly, we may construct a pair of exponentially distributed random variables with any feasible correlation...

  13. W-transform for exponential stability of second order delay differential equations without damping terms.

    Science.gov (United States)

    Domoshnitsky, Alexander; Maghakyan, Abraham; Berezansky, Leonid

    2017-01-01

    In this paper a method for studying stability of the equation [Formula: see text] not including explicitly the first derivative is proposed. We demonstrate that although the corresponding ordinary differential equation [Formula: see text] is not exponentially stable, the delay equation can be exponentially stable.

  14. Almost sure exponential stability of stochastic fuzzy cellular neural networks with delays

    International Nuclear Information System (INIS)

    Zhao Hongyong; Ding Nan; Chen Ling

    2009-01-01

    This paper is concerned with the problem of exponential stability analysis for fuzzy cellular neural network with delays. By constructing suitable Lyapunov functional and using stochastic analysis we present some sufficient conditions ensuring almost sure exponential stability for the network. Moreover, an example is given to demonstrate the advantages of our method.

  15. On Extended Exponential General Linear Methods PSQ with S>Q ...

    African Journals Online (AJOL)

    This paper is concerned with the construction and Numerical Analysis of Extended Exponential General Linear Methods. These methods, in contrast to other methods in literatures, consider methods with the step greater than the stage order (S>Q).Numerical experiments in this study, indicate that Extended Exponential ...

  16. Esscher transforms and the minimal entropy martingale measure for exponential Lévy models

    DEFF Research Database (Denmark)

    Hubalek, Friedrich; Sgarra, C.

    In this paper we offer a systematic survey and comparison of the Esscher martingale transform for linear processes, the Esscher martingale transform for exponential processes, and the minimal entropy martingale measure for exponential lévy models and present some new results in order to give...

  17. Afrika Statistika ISSN 2316-090X A note on a new exponential ...

    African Journals Online (AJOL)

    Let {Xn,n ≥ 1} be a sequence of random variables defined on a fixed probability space. (Ω, F, P). An exponential inequality ... Now as to the probability inequality field, as pointed out by Sung et al. (2011), exponential inequalities for ..... associated random variables. Journal of Statistical Planning and inference, 138, 4132-.

  18. The Q-Exponential Decay of Subjective Probability for Future Reward: A Psychophysical Time Approach

    Directory of Open Access Journals (Sweden)

    Taiki Takahashi

    2014-10-01

    Full Text Available This study experimentally examined why subjective probability for delayed reward decays non-exponentially (“hyperbolically”, i.e., q ˂ 1 in the q-exponential discount function in humans. Our results indicate that nonlinear psychophysical time causes hyperbolic time-decay of subjective probability for delayed reward. Implications for econophysics and neuroeconomics are discussed.

  19. Hypervolatiles in a Jupiter-family Comet: Observations of 45P/Honda-Mrkos-Pajdušáková Using iSHELL at the NASA-IRTF

    Science.gov (United States)

    DiSanti, Michael A.; Bonev, Boncho P.; Dello Russo, Neil; Vervack, Ronald J., Jr.; Gibb, Erika L.; Roth, Nathan X.; McKay, Adam J.; Kawakita, Hideyo; Feaga, Lori M.; Weaver, Harold A.

    2017-12-01

    We used the new high spectral resolution cross-dispersed facility spectrograph, iSHELL, at the NASA Infrared Telescope Facility on Maunakea, HI, to observe Jupiter-family comet (JFC) 45P/Honda-Mrkos-Pajdušáková. We report water production rates, as well as production rates and abundance ratios relative to H2O, for eight trace parent molecules (native ices), CO, CH4, H2CO, CH3OH, HCN, NH3, C2H2, and C2H6, on 2 days spanning UT 2017 January 6/7 and 7/8, shortly following perihelion. Trace species were measured simultaneously with H2O and/or OH prompt emission, a proxy for H2O production, thereby providing a robust and consistent means of establishing the native ice composition of 45P. Its favorable geocentric radial velocity (approximately -35 km s-1) permitted sensitive measures of the “hypervolatiles” CO and CH4, which are substantially undercharacterized in JFCs. Our results represent the most precise ground-based measures of CO and CH4 to date in a JFC, providing a foundation for building meaningful statistics regarding their abundances. The abundance ratio for CH4 in 45P (0.79% ± 0.06% relative to H2O) was consistent with its median value as measured among Oort Cloud comets, whereas CO (0.60% ± 0.04%) was strongly depleted. Compared with all measured comets, HCN (0.049% ± 0.012%) was strongly depleted, CH3OH (3.6% ± 0.3%) was enriched, and the remaining species were consistent with their respective median abundances. The volatile composition measured for 45P could indicate processing of ices prior to their incorporation into its nucleus. Spatial analysis of emissions suggests enhanced release of more volatile species into the sunward-facing hemisphere of the coma.

  20. Survival analysis approach to account for non-exponential decay rate effects in lifetime experiments

    International Nuclear Information System (INIS)

    Coakley, K.J.; Dewey, M.S.; Huber, M.G.; Huffer, C.R.; Huffman, P.R.; Marley, D.E.; Mumm, H.P.; O'Shaughnessy, C.M.; Schelhammer, K.W.; Thompson, A.K.; Yue, A.T.

    2016-01-01

    In experiments that measure the lifetime of trapped particles, in addition to loss mechanisms with exponential survival probability functions, particles can be lost by mechanisms with non-exponential survival probability functions. Failure to account for such loss mechanisms produces systematic measurement error and associated systematic uncertainties in these measurements. In this work, we develop a general competing risks survival analysis method to account for the joint effect of loss mechanisms with either exponential or non-exponential survival probability functions, and a method to quantify the size of systematic effects and associated uncertainties for lifetime estimates. As a case study, we apply our survival analysis formalism and method to the Ultra Cold Neutron lifetime experiment at NIST. In this experiment, neutrons can escape a magnetic trap before they decay due to a wall loss mechanism with an associated non-exponential survival probability function.

  1. An exact formulation of the time-ordered exponential using path-sums

    International Nuclear Information System (INIS)

    Giscard, P.-L.; Lui, K.; Thwaite, S. J.; Jaksch, D.

    2015-01-01

    We present the path-sum formulation for the time-ordered exponential of a time-dependent matrix. The path-sum formulation gives the time-ordered exponential as a branched continued fraction of finite depth and breadth. The terms of the path-sum have an elementary interpretation as self-avoiding walks and self-avoiding polygons on a graph. Our result is based on a representation of the time-ordered exponential as the inverse of an operator, the mapping of this inverse to sums of walks on a graphs, and the algebraic structure of sets of walks. We give examples demonstrating our approach. We establish a super-exponential decay bound for the magnitude of the entries of the time-ordered exponential of sparse matrices. We give explicit results for matrices with commonly encountered sparse structures

  2. An exact formulation of the time-ordered exponential using path-sums

    Science.gov (United States)

    Giscard, P.-L.; Lui, K.; Thwaite, S. J.; Jaksch, D.

    2015-05-01

    We present the path-sum formulation for the time-ordered exponential of a time-dependent matrix. The path-sum formulation gives the time-ordered exponential as a branched continued fraction of finite depth and breadth. The terms of the path-sum have an elementary interpretation as self-avoiding walks and self-avoiding polygons on a graph. Our result is based on a representation of the time-ordered exponential as the inverse of an operator, the mapping of this inverse to sums of walks on a graphs, and the algebraic structure of sets of walks. We give examples demonstrating our approach. We establish a super-exponential decay bound for the magnitude of the entries of the time-ordered exponential of sparse matrices. We give explicit results for matrices with commonly encountered sparse structures.

  3. Survival analysis approach to account for non-exponential decay rate effects in lifetime experiments

    Science.gov (United States)

    Coakley, K. J.; Dewey, M. S.; Huber, M. G.; Huffer, C. R.; Huffman, P. R.; Marley, D. E.; Mumm, H. P.; O`Shaughnessy, C. M.; Schelhammer, K. W.; Thompson, A. K.; Yue, A. T.

    2016-03-01

    In experiments that measure the lifetime of trapped particles, in addition to loss mechanisms with exponential survival probability functions, particles can be lost by mechanisms with non-exponential survival probability functions. Failure to account for such loss mechanisms produces systematic measurement error and associated systematic uncertainties in these measurements. In this work, we develop a general competing risks survival analysis method to account for the joint effect of loss mechanisms with either exponential or non-exponential survival probability functions, and a method to quantify the size of systematic effects and associated uncertainties for lifetime estimates. As a case study, we apply our survival analysis formalism and method to the Ultra Cold Neutron lifetime experiment at NIST. In this experiment, neutrons can escape a magnetic trap before they decay due to a wall loss mechanism with an associated non-exponential survival probability function.

  4. Survival analysis approach to account for non-exponential decay rate effects in lifetime experiments

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, K.J., E-mail: kevincoakley@nist.gov [National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305 (United States); Dewey, M.S.; Huber, M.G. [National Institute of Standards and Technology, 100 Bureau Drive, Stop 8461, Gaithersburg, MD 20899 (United States); Huffer, C.R.; Huffman, P.R. [North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory, 116 Science Drive, Box 90308, Durham, NC 27708 (United States); Marley, D.E. [National Institute of Standards and Technology, 100 Bureau Drive, Stop 8461, Gaithersburg, MD 20899 (United States); North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Mumm, H.P. [National Institute of Standards and Technology, 100 Bureau Drive, Stop 8461, Gaithersburg, MD 20899 (United States); O' Shaughnessy, C.M. [University of North Carolina at Chapel Hill, 120 E. Cameron Ave., CB #3255, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, 116 Science Drive, Box 90308, Durham, NC 27708 (United States); Schelhammer, K.W. [North Carolina State University, 2401 Stinson Drive, Box 8202, Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory, 116 Science Drive, Box 90308, Durham, NC 27708 (United States); Thompson, A.K.; Yue, A.T. [National Institute of Standards and Technology, 100 Bureau Drive, Stop 8461, Gaithersburg, MD 20899 (United States)

    2016-03-21

    In experiments that measure the lifetime of trapped particles, in addition to loss mechanisms with exponential survival probability functions, particles can be lost by mechanisms with non-exponential survival probability functions. Failure to account for such loss mechanisms produces systematic measurement error and associated systematic uncertainties in these measurements. In this work, we develop a general competing risks survival analysis method to account for the joint effect of loss mechanisms with either exponential or non-exponential survival probability functions, and a method to quantify the size of systematic effects and associated uncertainties for lifetime estimates. As a case study, we apply our survival analysis formalism and method to the Ultra Cold Neutron lifetime experiment at NIST. In this experiment, neutrons can escape a magnetic trap before they decay due to a wall loss mechanism with an associated non-exponential survival probability function.

  5. Waveform inversion with exponential damping using a deconvolution-based objective function

    KAUST Repository

    Choi, Yun Seok

    2016-09-06

    The lack of low frequency components in seismic data usually leads full waveform inversion into the local minima of its objective function. An exponential damping of the data, on the other hand, generates artificial low frequencies, which can be used to admit long wavelength updates for waveform inversion. Another feature of exponential damping is that the energy of each trace also exponentially decreases with source-receiver offset, where the leastsquare misfit function does not work well. Thus, we propose a deconvolution-based objective function for waveform inversion with an exponential damping. Since the deconvolution filter includes a division process, it can properly address the unbalanced energy levels of the individual traces of the damped wavefield. Numerical examples demonstrate that our proposed FWI based on the deconvolution filter can generate a convergent long wavelength structure from the artificial low frequency components coming from an exponential damping.

  6. Assessment of nutrition and physical activity environments in family child care homes: modification and psychometric testing of the Environment and Policy Assessment and Observation.

    Science.gov (United States)

    Vaughn, Amber E; Mazzucca, Stephanie; Burney, Regan; Østbye, Truls; Benjamin Neelon, Sara E; Tovar, Alison; Ward, Dianne S

    2017-08-29

    Early care and education (ECE) settings play an important role in shaping the nutrition and physical activity habits of young children. Increasing research attention is being directed toward family child care homes (FCCHs) specifically. However, existing measures of child care nutrition and physical activity environments are limited in that they have been created for use with center-based programs and require modification for studies involving FCCHs. This paper describes the modification of the Environment and Policy Assessment and Observation (EPAO) for use in FCCHs. The EPAO underwent a through modification process that incorporated an updated format for the data collection instrument, assessment of emerging best practices, tailoring to the FCCH environment, and creation of a new scoring rubric. The new instrument was implemented as part of a larger randomized control trial. To assess inter-rater reliability, observations on 61 different days were performed independently by two data collectors. To assess construct validity, associations between EPAO scores and measures of children's dietary intake (Healthy Eating Index (HEI) score) and physical activity (accelerometer-measured minutes per hour of moderate to vigorous physical activity, MVPA) were examined. The modified EPAO assesses 38 nutrition and 27 physical activity best practices, which can be summarized into 7 nutrition-related and 10 physical activity-related environmental sub- scores as well as overall nutrition and overall physical activity scores. There was generally good agreement between data collectors (ICC > 0.60). Reliability was slightly lower for feeding practices and physical activity education and professional development (ICC = 0.56 and 0.22, respectively). Child HEI was significantly correlated with the overall nutrition score (r = 0.23), foods provided (r = 0.28), beverages provided (r = 0.15), nutrition education and professional development (r = 0.21), and nutrition policy (r

  7. Assessment of nutrition and physical activity environments in family child care homes: modification and psychometric testing of the Environment and Policy Assessment and Observation

    Directory of Open Access Journals (Sweden)

    Amber E. Vaughn

    2017-08-01

    Full Text Available Abstract Background Early care and education (ECE settings play an important role in shaping the nutrition and physical activity habits of young children. Increasing research attention is being directed toward family child care homes (FCCHs specifically. However, existing measures of child care nutrition and physical activity environments are limited in that they have been created for use with center-based programs and require modification for studies involving FCCHs. This paper describes the modification of the Environment and Policy Assessment and Observation (EPAO for use in FCCHs. Methods The EPAO underwent a through modification process that incorporated an updated format for the data collection instrument, assessment of emerging best practices, tailoring to the FCCH environment, and creation of a new scoring rubric. The new instrument was implemented as part of a larger randomized control trial. To assess inter-rater reliability, observations on 61 different days were performed independently by two data collectors. To assess construct validity, associations between EPAO scores and measures of children’s dietary intake (Healthy Eating Index (HEI score and physical activity (accelerometer-measured minutes per hour of moderate to vigorous physical activity, MVPA were examined. Results The modified EPAO assesses 38 nutrition and 27 physical activity best practices, which can be summarized into 7 nutrition-related and 10 physical activity-related environmental sub- scores as well as overall nutrition and overall physical activity scores. There was generally good agreement between data collectors (ICC > 0.60. Reliability was slightly lower for feeding practices and physical activity education and professional development (ICC = 0.56 and 0.22, respectively. Child HEI was significantly correlated with the overall nutrition score (r = 0.23, foods provided (r = 0.28, beverages provided (r = 0.15, nutrition education and professional

  8. Transition from Exponential to Power Law Income Distributions in a Chaotic Market

    Science.gov (United States)

    Pellicer-Lostao, Carmen; Lopez-Ruiz, Ricardo

    Economy is demanding new models, able to understand and predict the evolution of markets. To this respect, Econophysics offers models of markets as complex systems, that try to comprehend macro-, system-wide states of the economy from the interaction of many agents at micro-level. One of these models is the gas-like model for trading markets. This tries to predict money distributions in closed economies and quite simply, obtains the ones observed in real economies. However, it reveals technical hitches to explain the power law distribution, observed in individuals with high incomes. In this work, nonlinear dynamics is introduced in the gas-like model in an effort to overcomes these flaws. A particular chaotic dynamics is used to break the pairing symmetry of agents (i, j) ⇔ (j, i). The results demonstrate that a "chaotic gas-like model" can reproduce the Exponential and Power law distributions observed in real economies. Moreover, it controls the transition between them. This may give some insight of the micro-level causes that originate unfair distributions of money in a global society. Ultimately, the chaotic model makes obvious the inherent instability of asymmetric scenarios, where sinks of wealth appear and doom the market to extreme inequality.

  9. Almost Surely Exponential Stability of Numerical Solutions for Stochastic Pantograph Equations

    Directory of Open Access Journals (Sweden)

    Shaobo Zhou

    2014-01-01

    Full Text Available Our effort is to develop a criterion on almost surely exponential stability of numerical solution to stochastic pantograph differential equations, with the help of the discrete semimartingale convergence theorem and the technique used in stable analysis of the exact solution. We will prove that the Euler-Maruyama (EM method can preserve almost surely exponential stability of stochastic pantograph differential equations under the linear growth conditions. And the backward EM method can reproduce almost surely exponential stability for highly nonlinear stochastic pantograph differential equations. A highly nonlinear example is provided to illustrate the main theory.

  10. Global exponential stability of fuzzy cellular neural networks with delays and reaction-diffusion terms

    International Nuclear Information System (INIS)

    Wang Jian; Lu Junguo

    2008-01-01

    In this paper, we study the global exponential stability of fuzzy cellular neural networks with delays and reaction-diffusion terms. By constructing a suitable Lyapunov functional and utilizing some inequality techniques, we obtain a sufficient condition for the uniqueness and global exponential stability of the equilibrium solution for a class of fuzzy cellular neural networks with delays and reaction-diffusion terms. The result imposes constraint conditions on the network parameters independently of the delay parameter. The result is also easy to check and plays an important role in the design and application of globally exponentially stable fuzzy neural circuits

  11. Noise suppress or express exponential growth for hybrid Hopfield neural networks

    International Nuclear Information System (INIS)

    Zhu Song; Shen Yi; Chen Guici

    2010-01-01

    In this Letter, we will show that noise can make the given hybrid Hopfield neural networks whose solution may grows exponentially become the new stochastic hybrid Hopfield neural networks whose solution will grows at most polynomially. On the other hand, we will also show that noise can make the given hybrid Hopfield neural networks whose solution grows at most polynomially become the new stochastic hybrid Hopfield neural networks whose solution will grows at exponentially. In other words, we will reveal that the noise can suppress or express exponential growth for hybrid Hopfield neural networks.

  12. Equivalent Method of Solving Quantum Efficiency of Reflection-Mode Exponential Doping GaAs Photocathode

    International Nuclear Information System (INIS)

    Jun, Niu; Zhi, Yang; Ben-Kang, Chang

    2009-01-01

    The mathematical expression of the electron diffusion and drift length L DE of exponential doping photocathode is deduced. In the quantum efficiency equation of the reffection-mode uniform doping cathode, substituting L DE for L D , the equivalent quantum efficiency equation of the reffection-mode exponential doping cathode is obtained. By using the equivalent equation, theoretical simulation and experimental analysis shows that the equivalent index formula and formula-doped cathode quantum efficiency results in line. The equivalent equation avoids complicated calculation, thereby simplifies the process of solving the quantum efficiency of exponential doping photocathode

  13. Globally exponential stability of neural network with constant and variable delays

    International Nuclear Information System (INIS)

    Zhao Weirui; Zhang Huanshui

    2006-01-01

    This Letter presents new sufficient conditions of globally exponential stability of neural networks with delays. We show that these results generalize recently published globally exponential stability results. In particular, several different globally exponential stability conditions in the literatures which were proved using different Lyapunov functionals are generalized and unified by using the same Lyapunov functional and the technique of inequality of integral. A comparison between our results and the previous results admits that our results establish a new set of stability criteria for delayed neural networks. Those conditions are less restrictive than those given in the earlier references

  14. Robust exponential stability and domains of attraction in a class of interval neural networks

    International Nuclear Information System (INIS)

    Yang Xiaofan; Liao Xiaofeng; Bai Sen; Evans, David J

    2005-01-01

    This paper addresses robust exponential stability as well as domains of attraction in a class of interval neural networks. A sufficient condition for an equilibrium point to be exponentially stable is established. And an estimate on the domains of attraction of exponentially stable equilibrium points is presented. Both the condition and the estimate are formulated in terms of the parameter intervals, the neurons' activation functions and the equilibrium point. Hence, they are easily checkable. In addition, our results neither depend on monotonicity of the activation functions nor on coupling conditions between the neurons. Consequently, these results are of practical importance in evaluating the performance of interval associative memory networks

  15. The dynamics of photoinduced defect creation in amorphous chalcogenides: The origin of the stretched exponential function

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, R. J. [Department of Electrical and Electronic Engineering, National University of Timor Lorosa' e, Av. Cidade de Lisboa, Dili, East Timor (Portugal); Shimakawa, K. [Department of General and Inorganic Chemistry, University of Pardubice, Pardubice 53002 (Czech Republic); Department of Electrical and Electronic Engineering, Gifu University, Gifu 501-1193 (Japan); Wagner, T. [Department of General and Inorganic Chemistry, University of Pardubice, Pardubice 53002 (Czech Republic)

    2014-01-07

    The article discusses the dynamics of photoinduced defect creations (PDC) in amorphous chalcogenides, which is described by the stretched exponential function (SEF), while the well known photodarkening (PD) and photoinduced volume expansion (PVE) are governed only by the exponential function. It is shown that the exponential distribution of the thermal activation barrier produces the SEF in PDC, suggesting that thermal energy, as well as photon energy, is incorporated in PDC mechanisms. The differences in dynamics among three major photoinduced effects (PD, PVE, and PDC) in amorphous chalcogenides are now well understood.

  16. Profiling of Campylobacter jejuni Proteome in Exponential and Stationary Phase of Growth

    Directory of Open Access Journals (Sweden)

    Hana Turonova

    2017-05-01

    Full Text Available Campylobacter jejuni has been reported as a major cause of bacterial food-borne enteritides in developed countries during the last decade. Despite its fastidious growth requirements, including low level of oxygen and high level of CO2, this pathogen is able to persist in the environment without permanent loss of its viability and virulence. As C. jejuni is not able to multiply outside a host, the cells spend significant amount of time in stationary phase of growth. The entry into the stationary phase is often correlated to resistance to various stresses in bacteria. The switching between exponential and stationary phases is frequently mediated by the regulator sigma S (RpoS. However, this factor is absent in C. jejuni and molecular mechanisms responsible for transition of cells to the stationary phase remain elusive. In this work, proteomic profiles of cells from exponential and stationary phases were compared using 2-D electrophoresis (2DE fingerprinting combined with mass spectrometry analysis and qRT-PCR. The identified proteins, whose expression differed between the two phases, are mostly involved in protein biosynthesis, carbon metabolism, stress response and motility. Altered expression was observed also in the pleiotropic regulator CosR that was over-expressed during stationary phase. A shift between transcript and protein level evolution of CosR throughout the growth of C. jejuni was observed using qRT-PCR and (2DE. From these data, we hypothesized that CosR could undergo a negative autoregulation in stationary phase. A consensus sequence resulting from promoter sequence alignment of genes potentially regulated by CosR, including its own upstream region, among C. jejuni strains is proposed. To verify experimentally the potential autoregulation of CosR at the DNA level, electrophoretic mobility shift assay was performed with DNA fragments of CosR promoter region and rCosR. Different migration pattern of the promoter fragments indicates

  17. Hemopoietic stem-cell compartment of the SCID mouse: Double-exponential survival curve after γ irradiation

    International Nuclear Information System (INIS)

    Taniguchi, Satoshi; Hirabayashi, Yoko; Inoue, Tohru; Kanisawa, Masayoshi; Sasaki, Hideki; Komatsu, Kenshi; Mori, K.J.

    1993-01-01

    It has been reported that SCID (severe combined immunodeficiency, scid/scid) mice are more radiosensitive than normal mice. In the present studies, graded doses of radiation were given to bone marrow cells from SCID mice, and double-exponential survival curves were observed for day-9 and day-12 colony-forming units in the spleen (CFU-S). Single-exponential curves were found for SCID CFU in in vitro assays for granulocyte/macrophage-CFUs and erythroid burst-forming units, as reported elsewhere. Since the size of this more resistant fraction seems to decrease with stem-cell maturation, the finding implies that this fraction is a primitive subpopulation of the stem-cell compartment. The mean lethal dose (D 0 ), however, of this less sensitive SCID CFU-S is much less than the D 0 of regular CFU-S in normal littermates. Spleen colonies produced by SCID bone marrow were relatively small and abortive. The size of these colonies decreased nearly exponentially with increasing doses of radiation. These colonies produced by the sensitive fraction have disappeared, being killed by a relatively low dose of radiation. This observation might account for the high lymphomagenesis arising from primitive hemopoietic stem cells in SCID mice, because the smallness of the colonies suggests that there is unrepaired or misrepaired damage. Furthermore, this less sensitive fraction might be a source of the open-quotes leakyclose quotes change of T and B cells, possibly due to the induction of an equivocal repair system which appears in the later stages of life in the SCID mice. 34 refs., 5 figs., 3 tabs

  18. Infant feeding patterns in families with a diabetes history - observations from The Environmental Determinants of Diabetes in the Young (TEDDY) birth cohort study.

    Science.gov (United States)

    Hummel, Sandra; Vehik, Kendra; Uusitalo, Ulla; McLeod, Wendy; Aronsson, Carin Andrén; Frank, Nicole; Gesualdo, Patricia; Yang, Jimin; Norris, Jill M; Virtanen, Suvi M

    2014-12-01

    To assess the association between diabetes family history and infant feeding patterns. Data on breast-feeding duration and age at first introduction of cow's milk and gluten-containing cereals were collected in 3-month intervals during the first 24 months of life. Data from the multicentre TEDDY (The Environmental Determinants of Diabetes in the Young) study, including centres in the USA, Sweden, Finland and Germany. A total of 7026 children, including children with a mother with type 1 diabetes (T1D; n 292), gestational diabetes mellitus (GDM; n 404) or without diabetes but with a father and/or sibling with T1D (n 464) and children without diabetes family history (n 5866). While exclusive breast-feeding ended earlier and cow's milk was introduced earlier in offspring of mothers with T1D and GDM, offspring of non-diabetic mothers but a father and/or sibling with T1D were exclusively breast-fed longer and introduced to cow's milk later compared with infants without diabetes family history. The association between maternal diabetes and shorter exclusive breast-feeding duration was attenuated after adjusting for clinical variables (delivery mode, gestational age, Apgar score and birth weight). Country-specific analyses revealed differences in these associations, with Sweden showing the strongest and Finland showing no association between maternal diabetes and breast-feeding duration. Family history of diabetes is associated with infant feeding patterns; however, the associations clearly differ by country, indicating that cultural differences are important determinants of infant feeding behaviour. These findings need to be considered when developing strategies to improve feeding patterns in infants with a diabetes family history.

  19. Exponential functionals of Brownian motion, I: Probability laws at fixed time

    OpenAIRE

    Matsumoto, Hiroyuki; Yor, Marc

    2005-01-01

    This paper is the first part of our survey on various results about the distribution of exponential type Brownian functionals defined as an integral over time of geometric Brownian motion. Several related topics are also mentioned.

  20. Sharp error terms and neccesary conditions for exponential hitting times in mixing processes

    CERN Document Server

    Abadi, M G

    2001-01-01

    We prove an upper bound for the error in the exponential approximation of the hitting time law of a rare event in $\\alpha$-mixing processes with exponential decay, $\\phi$-mixing processes with a summable function $\\phi$ and for general $\\psi$-mixing processes with a finite alphabet. In the first case the bound is uniform as a function of the measure of the event. In the last two cases the bound depends also on the time scale $t$. This allow us to get further statistical properties as the ratio convergence of the expected hitting time and the expected return time. A uniform bound is a consequence. We present an example that shows that this bound is sharp. We also prove that second moments are not necessary for having the exponential law. Moreover, we prove a necessary condition for having the exponential limit law.

  1. Fitting of alpha-efficiency versus quenching parameter by exponential functions in liquid scintillation counting

    International Nuclear Information System (INIS)

    Sosa, M.; Manjón, G.; Mantero, J.; García-Tenorio, R.

    2014-01-01

    The objective of this work is to propose an exponential fit for the low alpha-counting efficiency as a function of a sample quenching parameter using a Quantulus liquid scintillation counter. The sample quenching parameter in a Quantulus is the Spectral Quench Parameter of the External Standard (SQP(E)), which is defined as the number of channel under which lies the 99% of Compton spectrum generated by a gamma emitter ( 152 Eu). Although in the literature one usually finds a polynomial fitting of the alpha counting efficiency, it is shown here that an exponential function is a better description. - Highlights: • We have studied the quenching in alpha measurement by liquid scintillation counting. • We have reviewed typical fitting of alpha counting efficiency versus quenching parameter. • Exponential fitting of data is proposed as better fitting. • We consider exponential fitting has a physical basis

  2. Fitting of alpha-efficiency versus quenching parameter by exponential functions in liquid scintillation counting

    Energy Technology Data Exchange (ETDEWEB)

    Sosa, M. [Departamento de Ingeniería Física, Campus León, Universidad de Guanajuato, 37150 León, Guanajuato (Mexico); Universidad de Sevilla, Departamento de Física Aplicada II, E.T.S. Arquitectura, Av. Reina Mercedes, 2, 41012 Sevilla (Spain); Manjón, G., E-mail: manjon@us.es [Universidad de Sevilla, Departamento de Física Aplicada II, E.T.S. Arquitectura, Av. Reina Mercedes, 2, 41012 Sevilla (Spain); Mantero, J.; García-Tenorio, R. [Universidad de Sevilla, Departamento de Física Aplicada II, E.T.S. Arquitectura, Av. Reina Mercedes, 2, 41012 Sevilla (Spain)

    2014-05-01

    The objective of this work is to propose an exponential fit for the low alpha-counting efficiency as a function of a sample quenching parameter using a Quantulus liquid scintillation counter. The sample quenching parameter in a Quantulus is the Spectral Quench Parameter of the External Standard (SQP(E)), which is defined as the number of channel under which lies the 99% of Compton spectrum generated by a gamma emitter ({sup 152}Eu). Although in the literature one usually finds a polynomial fitting of the alpha counting efficiency, it is shown here that an exponential function is a better description. - Highlights: • We have studied the quenching in alpha measurement by liquid scintillation counting. • We have reviewed typical fitting of alpha counting efficiency versus quenching parameter. • Exponential fitting of data is proposed as better fitting. • We consider exponential fitting has a physical basis.

  3. Global impulsive exponential synchronization of stochastic perturbed chaotic delayed neural networks

    International Nuclear Information System (INIS)

    Hua-Guang, Zhang; Tie-Dong, Ma; Jie, Fu; Shao-Cheng, Tong

    2009-01-01

    In this paper, the global impulsive exponential synchronization problem of a class of chaotic delayed neural networks (DNNs) with stochastic perturbation is studied. Based on the Lyapunov stability theory, stochastic analysis approach and an efficient impulsive delay differential inequality, some new exponential synchronization criteria expressed in the form of the linear matrix inequality (LMI) are derived. The designed impulsive controller not only can globally exponentially stabilize the error dynamics in mean square, but also can control the exponential synchronization rate. Furthermore, to estimate the stable region of the synchronization error dynamics, a novel optimization control algorithm is proposed, which can deal with the minimum problem with two nonlinear terms coexisting in LMIs effectively. Simulation results finally demonstrate the effectiveness of the proposed method

  4. Double-Exponentially Decayed Photoionization in CREI Effect: Numerical Experiment on 3D H2+

    International Nuclear Information System (INIS)

    Feng, Li; Ting-Ying, Wang; Gui-Zhong, Zhang; Wang-Hua, Xiang; III, W. T. Hill

    2008-01-01

    On the platform of the 3D H 2 + system, we perform a numerical simulation of its photoionization rate under excitation of weak to intense laser intensities with varying pulse durations and wavelengths. A novel method is proposed for calculating the photoionization rate: a double exponential decay of ionization probability is best suited for fitting this rate. Confirmation of the well-documented charge-resonance-enhanced ionization (CREI) effect at medium laser intensity and finding of ionization saturation at high light intensity corroborate the robustness of the suggested double-exponential decay process. Surveying the spatial and temporal variations of electron wavefunctions uncovers a mechanism for the double-exponentially decayed photoionization probability as onset of electron ionization along extra degree of freedom. Henceforth, the new method makes clear the origins of peak features in photoionization rate versus internuclear separation. It is believed that this multi-exponentially decayed ionization mechanism is applicable to systems with more degrees of motion

  5. Nonlinear Schrodinger elliptic systems involving exponential critical growth in R^2

    Directory of Open Access Journals (Sweden)

    Francisco S. B. Albuquerque Albuquerque

    2014-02-01

    Full Text Available This article concerns the existence and multiplicity of solutions for elliptic systems with weights, and nonlinearities having exponential critical growth. Our approach is based on the Trudinger-Moser inequality and on a minimax theorem.

  6. Absolute exponential stability of recurrent neural networks with Lipschitz-continuous activation functions and time delays.

    Science.gov (United States)

    Cao, Jinde; Wang, Jun

    2004-04-01

    This paper investigates the absolute exponential stability of a general class of delayed neural networks, which require the activation functions to be partially Lipschitz continuous and monotone nondecreasing only, but not necessarily differentiable or bounded. Three new sufficient conditions are derived to ascertain whether or not the equilibrium points of the delayed neural networks with additively diagonally stable interconnection matrices are absolutely exponentially stable by using delay Halanay-type inequality and Lyapunov function. The stability criteria are also suitable for delayed optimization neural networks and delayed cellular neural networks whose activation functions are often nondifferentiable or unbounded. The results herein answer a question: if a neural network without any delay is absolutely exponentially stable, then under what additional conditions, the neural networks with delay is also absolutely exponentially stable.

  7. A note on a new exponential bound for M-acceptable random ...

    African Journals Online (AJOL)

    We compare the given bound with former ones. Key words: Exponential inequality; Convergence rate; Almost sure convergence; M- Acceptable random variables; Negatively associated random variables; Negatively dependent random variables; Extended Negatively dependent random variables; Laplace transform.

  8. Fast exponential calculation for the IBM 370-195 at the Oak Ridge Gaseous Diffusion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Whitson, J. C.; Whealton, J. H.

    1977-01-01

    The time spent for computing an exponential for the IBM 370-195 at the Oak Ridge Gaseous Diffusion Plant is about 25 times slower than that spent by the CDC-7600 CTR computer at Livermore. We propose a scheme which does not involve a function call, is 15 times faster than the IBM 370-195 scheme, and is useful when the exponential is called many times.

  9. The Logarithmic Potential and an Exponential Mass Function for Elementary Particles

    Directory of Open Access Journals (Sweden)

    Paasch K.

    2009-01-01

    Full Text Available The assumption that elementary particles with nonzero rest mass consist of relativistic constituents moving with constant energy, pc, results in a logarithmic potential and exponential expression for particle masses. This approach is put to a test by assigning each elementary particles mass a position on a logarithmic spiral. Particles then accumulate on straight lines. It is discussed if this might be an indication for exponential mass quantization.

  10. Exponential stability analysis for delayed stochastic Cohen-Grossberg neural network

    Directory of Open Access Journals (Sweden)

    Guanjun Wang

    2010-04-01

    Full Text Available In this paper, the exponential stability problems are addressed for a class of delayed Cohen-Grossberg neural networks which are also perturbed by some stochastic noises. By employing the Lyapunov method, stochastic analysis and some inequality techniques, sufficient conditions are acquired for checking the pth(p g 1 and the 1st moment exponential stability of the network. Finally, One example is given to show the effectiveness of the proposed results.

  11. Global exponential stability of reaction-diffusion recurrent neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Liang Jinling; Cao Jinde

    2003-01-01

    Employing general Halanay inequality, we analyze the global exponential stability of a class of reaction-diffusion recurrent neural networks with time-varying delays. Several new sufficient conditions are obtained to ensure existence, uniqueness and global exponential stability of the equilibrium point of delayed reaction-diffusion recurrent neural networks. The results extend and improve the earlier publications. In addition, an example is given to show the effectiveness of the obtained result

  12. Global exponential stability of mixed discrete and distributively delayed cellular neural network

    International Nuclear Information System (INIS)

    Yao Hong-Xing; Zhou Jia-Yan

    2011-01-01

    This paper concernes analysis for the global exponential stability of a class of recurrent neural networks with mixed discrete and distributed delays. It first proves the existence and uniqueness of the balance point, then by employing the Lyapunov—Krasovskii functional and Young inequality, it gives the sufficient condition of global exponential stability of cellular neural network with mixed discrete and distributed delays, in addition, the example is provided to illustrate the applicability of the result. (general)

  13. The motion planning problem and exponential stabilization of a heavy chain. Part II

    OpenAIRE

    Piotr Grabowski

    2008-01-01

    This is the second part of paper [P. Grabowski, The motion planning problem and exponential stabilization of a heavy chain. Part I, to appear in International Journal of Control], where a model of a heavy chain system with a punctual load (tip mass) in the form of a system of partial differential equations was interpreted as an abstract semigroup system and then analysed on a Hilbert state space. In particular, in [P. Grabowski, The motion planning problem and exponential stabilization of a h...

  14. Existence and exponential stability of almost periodic solution for stochastic cellular neural networks with delay

    International Nuclear Information System (INIS)

    Huang Zaitang; Yang Qigui

    2009-01-01

    The paper considers the problems of existence of quadratic mean almost periodic and global exponential stability for stochastic cellular neural networks with delays. By employing the Holder's inequality and fixed points principle, we present some new criteria ensuring existence and uniqueness of a quadratic mean almost periodic and global exponential stability. These criteria are important in signal processing and the design of networks. Moreover, these criteria are also applied in others stochastic biological neural systems.

  15. Clinical proteomics in kidney disease as an exponential technology: heading towards the disruptive phase

    OpenAIRE

    Sanchez-Ni?o, Maria Dolores; Sanz, Ana B.; Ramos, Adrian M.; Fernandez-Fernandez, Beatriz; Ortiz, Alberto

    2017-01-01

    Abstract Exponential technologies double in power or processing speed every year, whereas their cost halves. Deception and disruption are two key stages in the development of exponential technologies. Deception occurs when, after initial introduction, technologies are dismissed as irrelevant, while they continue to progress, perhaps not as fast or with so many immediate practical applications as initially thought. Twenty years after the first publications, clinical proteomics is still not ava...

  16. Globally exponential stability and periodic solutions of CNNS with variable coefficients and variable delays

    International Nuclear Information System (INIS)

    Liu Haifei; Wang Li

    2006-01-01

    In this Letter, by using the inequality method and the Lyapunov functional method, we analyze the globally exponential stability and the existence of periodic solutions of a class of cellular neutral networks with delays and variable coefficients. Some simple and new sufficient conditions ensuring the existence and uniqueness of globally exponential stability of periodic solutions for cellular neutral networks with variable coefficients and delays are obtained. In addition, one example is also worked out to illustrate our theory

  17. Exponential p-stability of impulsive stochastic differential equations with delays

    International Nuclear Information System (INIS)

    Yang Zhiguo; Xu Daoyi; Xiang Li

    2006-01-01

    In this Letter, we establish a method to study the exponential p-stability of the zero solution of impulsive stochastic differential equations with delays. By establishing an L-operator inequality and using the properties of M-cone and stochastic analysis technique, we obtain some new conditions ensuring the exponential p-stability of the zero solution of impulsive stochastic differential equations with delays. Two illustrative examples have been provided to show the effectiveness of our results

  18. Global exponential stability for reaction-diffusion recurrent neural networks with multiple time varying delays

    International Nuclear Information System (INIS)

    Lou, X.; Cui, B.

    2008-01-01

    In this paper we consider the problem of exponential stability for recurrent neural networks with multiple time varying delays and reaction-diffusion terms. The activation functions are supposed to be bounded and globally Lipschitz continuous. By means of Lyapunov functional, sufficient conditions are derived, which guarantee global exponential stability of the delayed neural network. Finally, a numerical example is given to show the correctness of our analysis. (author)

  19. Reactor parameters and constants determination by using measurements in subcritical and exponential assembly

    International Nuclear Information System (INIS)

    Voi, Dante Luiz; Santos Bastos, Wilma dos

    1995-01-01

    Subcritical and exponential experiments are important for Reactor Physics integral parameter determinations both to validate and confirm theoretical models for reactor calculations. An exponential and subcritical facility has been constructed to be used on the internal thermal column of the Argonauta reactor at IEN-CNEN- Rio de Janeiro. An experimental research program has been developed for the determination of fundamental reactor constants as buckling, migration areas, resonance escape probabilities, thermal utilization, fast fission and fuel eta factors. (author) 23 refs

  20. On the non-hyperbolicity of a class of exponential polynomials

    Directory of Open Access Journals (Sweden)

    Gaspar Mora

    2017-10-01

    Full Text Available In this paper we have constructed a class of non-hyperbolic exponential polynomials that contains all the partial sums of the Riemann zeta function. An exponential polynomial been also defined to illustrate the complexity of the structure of the set defined by the closure of the real projections of its zeros. The sensitivity of this set, when the vector of delays is perturbed, has been analysed. These results have immediate implications in the theory of the neutral differential equations.

  1. Analysis of friction autofluctuations of a drilling string with exponential resistance law

    Energy Technology Data Exchange (ETDEWEB)

    Belokobyl' skiy, S.V.; Prokopov, V.K.

    1981-01-01

    An analysis is made of the friction autofluctuations of a drilling string with exponential resistance law. A spasmodic resistance law is obtained from it as a particular case. It is demonstrated that for definite parameters, the amplitude of autofluctuations with the exponential resistance law exceeds the scope of fluctuations with the spasmodic law. Dependences are constructed for the period of autofluctuations and movement time on the parameters. Dangerous regimes of autofluctuations are defined.

  2. Globally exponential stability and periodic solutions of CNNS with variable coefficients and variable delays

    Energy Technology Data Exchange (ETDEWEB)

    Liu Haifei [School of Management and Engineering, Nanjing University, Nanjing 210093 (China)]. E-mail: hfliu80@126.com; Wang Li [School of Management and Engineering, Nanjing University, Nanjing 210093 (China)

    2006-09-15

    In this Letter, by using the inequality method and the Lyapunov functional method, we analyze the globally exponential stability and the existence of periodic solutions of a class of cellular neutral networks with delays and variable coefficients. Some simple and new sufficient conditions ensuring the existence and uniqueness of globally exponential stability of periodic solutions for cellular neutral networks with variable coefficients and delays are obtained. In addition, one example is also worked out to illustrate our theory.

  3. The true quantum face of the "exponential" decay: Unstable systems in rest and in motion

    Science.gov (United States)

    Urbanowski, K.

    2017-12-01

    Results of theoretical studies and numerical calculations presented in the literature suggest that the survival probability P0(t) has the exponential form starting from times much smaller than the lifetime τ up to times t ⪢τ and that P0(t) exhibits inverse power-law behavior at the late time region for times longer than the so-called crossover time T ⪢ τ (The crossover time T is the time when the late time deviations of P0(t) from the exponential form begin to dominate). More detailed analysis of the problem shows that in fact the survival probability P0(t) can not take the pure exponential form at any time interval including times smaller than the lifetime τ or of the order of τ and it has has an oscillating form. We also study the survival probability of moving relativistic unstable particles with definite momentum . These studies show that late time deviations of the survival probability of these particles from the exponential-like form of the decay law, that is the transition times region between exponential-like and non-exponential form of the survival probability, should occur much earlier than it follows from the classical standard considerations.

  4. Modified Exponential Weighted Moving Average (EWMA) Control Chart on Autocorrelation Data

    Science.gov (United States)

    Herdiani, Erna Tri; Fandrilla, Geysa; Sunusi, Nurtiti

    2018-03-01

    In general, observations of the statistical process control are assumed to be mutually independence. However, this assumption is often violated in practice. Consequently, statistical process controls were developed for interrelated processes, including Shewhart, Cumulative Sum (CUSUM), and exponentially weighted moving average (EWMA) control charts in the data that were autocorrelation. One researcher stated that this chart is not suitable if the same control limits are used in the case of independent variables. For this reason, it is necessary to apply the time series model in building the control chart. A classical control chart for independent variables is usually applied to residual processes. This procedure is permitted provided that residuals are independent. In 1978, Shewhart modification for the autoregressive process was introduced by using the distance between the sample mean and the target value compared to the standard deviation of the autocorrelation process. In this paper we will examine the mean of EWMA for autocorrelation process derived from Montgomery and Patel. Performance to be investigated was investigated by examining Average Run Length (ARL) based on the Markov Chain Method.

  5. Chemical reaction and radiation effects on MHD flow past an exponentially stretching sheet with heat sink

    Science.gov (United States)

    Nur Wahida Khalili, Noran; Aziz Samson, Abdul; Aziz, Ahmad Sukri Abdul; Ali, Zaileha Md

    2017-09-01

    In this study, the problem of MHD boundary layer flow past an exponentially stretching sheet with chemical reaction and radiation effects with heat sink is studied. The governing system of PDEs is transformed into a system of ODEs. Then, the system is solved numerically by using Runge-Kutta-Fehlberg fourth fifth order (RKF45) method available in MAPLE 15 software. The numerical results obtained are presented graphically for the velocity, temperature and concentration. The effects of various parameters are studied and analyzed. The numerical values for local Nusselt number, skin friction coefficient and local Sherwood number are tabulated and discussed. The study shows that various parameters give significant effect on the profiles of the fluid flow. It is observed that the reaction rate parameter affected the concentration profiles significantly and the concentration thickness of boundary layer decreases when reaction rate parameter increases. The analysis found is validated by comparing with the results previous work done and it is found to be in good agreement.

  6. Symplectic exponential Runge-Kutta methods for solving nonlinear Hamiltonian systems

    Science.gov (United States)

    Mei, Lijie; Wu, Xinyuan

    2017-06-01

    Symplecticity is also an important property for exponential Runge-Kutta (ERK) methods in the sense of structure preservation once the underlying problem is a Hamiltonian system, though ERK methods provide a good performance of higher accuracy and better efficiency than classical Runge-Kutta (RK) methods in dealing with stiff problems: y‧ (t) = My + f (y). On account of this observation, the main theme of this paper is to derive and analyze the symplectic conditions for ERK methods. Using the fundamental analysis of geometric integrators, we first establish one class of sufficient conditions for symplectic ERK methods. It is shown that these conditions will reduce to the conventional ones when M → 0, and this means that these conditions of symplecticity are extensions of the conventional ones in the literature. Furthermore, we also present a new class of structure-preserving ERK methods possessing the remarkable property of symplecticity. Meanwhile, the revised stiff order conditions are proposed and investigated in detail. Since the symplectic ERK methods are implicit and iterative solutions are required in practice, we also investigate the convergence of the corresponding fixed-point iterative procedure. Finally, the numerical experiments, including a nonlinear Schrödinger equation, a sine-Gordon equation, a nonlinear Klein-Gordon equation, and the well-known Fermi-Pasta-Ulam problem, are implemented in comparison with the corresponding symplectic RK methods and the prominent numerical results definitely coincide with the theories and conclusions made in this paper.

  7. Metabolic flux analysis during the exponential growth phase of Saccharomyces cerevisiae in wine fermentations.

    Science.gov (United States)

    Quirós, Manuel; Martínez-Moreno, Rubén; Albiol, Joan; Morales, Pilar; Vázquez-Lima, Felícitas; Barreiro-Vázquez, Antonio; Ferrer, Pau; Gonzalez, Ramon

    2013-01-01

    As a consequence of the increase in global average temperature, grapes with the adequate phenolic and aromatic maturity tend to be overripe by the time of harvest, resulting in increased sugar concentrations and imbalanced C/N ratios in fermenting musts. This fact sets obvious additional hurdles in the challenge of obtaining wines with reduced alcohols levels, a new trend in consumer demands. It would therefore be interesting to understand Saccharomyces cerevisiae physiology during the fermentation of must with these altered characteristics. The present study aims to determine the distribution of metabolic fluxes during the yeast exponential growth phase, when both carbon and nitrogen sources are in excess, using continuous cultures. Two different sugar concentrations were studied under two different winemaking temperature conditions. Although consumption and production rates for key metabolites were severely affected by the different experimental conditions studied, the general distribution of fluxes in central carbon metabolism was basically conserved in all cases. It was also observed that temperature and sugar concentration exerted a higher effect on the pentose phosphate pathway and glycerol formation than on glycolysis and ethanol production. Additionally, nitrogen uptake, both quantitatively and qualitatively, was strongly influenced by environmental conditions. This work provides the most complete stoichiometric model used for Metabolic Flux Analysis of S. cerevisiae in wine fermentations employed so far, including the synthesis and release of relevant aroma compounds and could be used in the design of optimal nitrogen supplementation of wine fermentations.

  8. Metabolic flux analysis during the exponential growth phase of Saccharomyces cerevisiae in wine fermentations.

    Directory of Open Access Journals (Sweden)

    Manuel Quirós

    Full Text Available As a consequence of the increase in global average temperature, grapes with the adequate phenolic and aromatic maturity tend to be overripe by the time of harvest, resulting in increased sugar concentrations and imbalanced C/N ratios in fermenting musts. This fact sets obvious additional hurdles in the challenge of obtaining wines with reduced alcohols levels, a new trend in consumer demands. It would therefore be interesting to understand Saccharomyces cerevisiae physiology during the fermentation of must with these altered characteristics. The present study aims to determine the distribution of metabolic fluxes during the yeast exponential growth phase, when both carbon and nitrogen sources are in excess, using continuous cultures. Two different sugar concentrations were studied under two different winemaking temperature conditions. Although consumption and production rates for key metabolites were severely affected by the different experimental conditions studied, the general distribution of fluxes in central carbon metabolism was basically conserved in all cases. It was also observed that temperature and sugar concentration exerted a higher effect on the pentose phosphate pathway and glycerol formation than on glycolysis and ethanol production. Additionally, nitrogen uptake, both quantitatively and qualitatively, was strongly influenced by environmental conditions. This work provides the most complete stoichiometric model used for Metabolic Flux Analysis of S. cerevisiae in wine fermentations employed so far, including the synthesis and release of relevant aroma compounds and could be used in the design of optimal nitrogen supplementation of wine fermentations.

  9. What are the physical and psychological health effects of suicide bereavement on family members? Protocol for an observational and interview mixed-methods study in Ireland.

    Science.gov (United States)

    Spillane, Ailbhe; Larkin, Celine; Corcoran, Paul; Matvienko-Sikar, Karen; Arensman, Ella

    2017-03-30

    Research indicates that experiencing the suicide of a relative can have a significant impact on family members' emotional health. However, research incorporating the impact of suicide bereavement on family members' physical health is sparse. This paper details the protocol for a mixed-methods study of suicide-bereaved family members. The study will primarily examine the physical and mental health needs of those bereaved by suicide. A secondary objective of the study is to describe the support service needs of family members bereaved by suicide. A mixed-methods approach, using semistructured interviews and self-report questionnaires, will be used. Interviews will be conducted with a group of 15-20 relatives who experienced suicide bereavement. This protocol will follow the COREQ checklist criteria for the reporting of qualitative research interviews. Thematic analysis will be used to examine experiences and impact of bereavement on psychological and physical health. Self-report quantitative data on well-being will be analysed using descriptive statistics. Ethical approval to conduct this study has been granted from the Clinical Research Ethics Committee of the Cork Teaching Hospitals. Pseudonyms will be given to participants to protect anonymity. It will be explained to participants that participation in the study is voluntary and they have to right to withdraw at any time. The findings of this research will be disseminated to regional, national and international audiences through publication in peer-reviewed international journals and presentations at scientific conferences. This research also forms part of a PhD thesis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  10. Quasiparticle Dynamics and Exponential Protection in Majorana Islands

    DEFF Research Database (Denmark)

    Albrecht, Sven Marian

    This thesis presents measurements on Majorana islands: semiconductor-superconductor hybrid nanowire quantum dots in the trivial and the topological superconducting phase. We fabricate Majorana island devices based on indium arsenide nanowires with an epitaxially matched aluminum half-shell. Measu...... simulations show good agreement with measurements and allow us to extract a time for poisoning of the island’s ground state from the leads of 3 microseconds....... Majorana modes. A preliminary analysis shows that Coulomb peaks also feature an alternating magnetic field dependent skew, the subject of future work. We additionally observe novel transport signatures of quasiparticle poisoning in a Majorana island strongly coupled to normal metal leads. Numerical...

  11. Dissolved families

    DEFF Research Database (Denmark)

    Christoffersen, Mogens

    The situation in the family preceding a family separation is studied here, to identify risk factors for family dissolution. Information registers covering prospective statistics about health aspects, demographic variables, family violence, self-destructive behaviour, unemployment, and the spousal...

  12. Flow behind an exponential shock wave in a rotational axisymmetric perfect gas with magnetic field and variable density.

    Science.gov (United States)

    Nath, G; Sahu, P K

    2016-01-01

    A self-similar model for one-dimensional unsteady isothermal and adiabatic flows behind a strong exponential shock wave driven out by a cylindrical piston moving with time according to an exponential law in an ideal gas in the presence of azimuthal magnetic field and variable density is discussed in a rotating atmosphere. The ambient medium is assumed to possess radial, axial and azimuthal component of fluid velocities. The initial density, the fluid velocities and magnetic field of the ambient medium are assumed to be varying with time according to an exponential law. The gas is taken to be non-viscous having infinite electrical conductivity. Solutions are obtained, in both the cases, when the flow between the shock and the piston is isothermal or adiabatic by taking into account the components of vorticity vector. The effects of the variation of the initial density index, adiabatic exponent of the gas and the Alfven-Mach number on the flow-field behind the shock wave are investigated. It is found that the presence of the magnetic field have decaying effects on the shock wave. Also, it is observed that the effect of an increase in the magnetic field strength is more impressive in the case of adiabatic flow than in the case of isothermal flow. The assumption of zero temperature gradient brings a profound change in the density, non-dimensional azimuthal and axial components of vorticity vector distributions in comparison to those in the case of adiabatic flow. A comparison is made between isothermal and adiabatic flows. It is obtained that an increase in the initial density variation index, adiabatic exponent and strength of the magnetic field decrease the shock strength.

  13. On super-exponential inflation in a higher-dimensional theory of gravity with higher-derivative terms

    International Nuclear Information System (INIS)

    Pollock, M.D.

    1988-01-01

    We consider super-exponential inflation in the early universe, for which H 2 /H = q >> 1, with particular reference to the higher-dimensional theory of Shafi and Wetterich, which is discussed in further detail. The Hubble parameter H is given by H 2 ≅ (8π/3m P 2 )V(Φ), where the ''inflation'' field Φ is related to the radius of the internal space, and obeys the equation of motion 3HΦ ≅ -dW/dΦ. The spectrum of density perturbations is given by δρ/ρ = (M/M 0 ) -s , where s -1 ≅ 3(q + 1); and X = (-dV/dΦ)/(dW/dΦ). The parameters q and X are both positive constants, hence the need for two distinct potentials, which can be met in a higher-dimensional theory with higher-derivative terms R 2 = α 1 R 2 + α 2 R AB R AB + α 3 R ABCD R ABCD . Some fine-tuning of the parameters α i and/or of the cosmological constant Λ is always necessary in order to have super-exponential inflation. It is possible to obtain a spectrum of density perturbations with s > or approx. 1/20, which helps to give agreement with observations of the cosmic microwave background radiation at very large scales ∝ 1000 Mpc. When R 2 is proportional to the Euler number density, making the four-dimensional theory free of ghosts, then super-exponential inflation is impossible, but a phase of inflation with H < 0 can still occur. (orig.)

  14. Family Obligations in Denmark

    DEFF Research Database (Denmark)

    Koch-Nielsen, Inger

    How is the balance in obligations between the Family and the Danish Welfare State? Can we observe a trend to shift the responsibility back to the family? This booklet intends to sketch the legal framework around the division of responsibilities between the Family and the state and to analyse...... to what extent and where the unit of rights and obliagations is the individual and where it is the family or household....

  15. Differences in inhibition by beta-arabinofuranosyladenine (araA) of radiation induced DNA damage repair in exponentially growing and plateau-phase CHO-cells

    International Nuclear Information System (INIS)

    Iliakis, G.; Seaner, R.

    1988-01-01

    The effect of beta-arabinofuranosyladenine (araA) on the repair of radiation induced DNA damage, as measured by the DNA unwinding technique, was studied in exponentially growing and plateau-phase CHO-cells after exposure to X-rays. Induction of DNA damage by radiation was found to be similar in exponentially growing and plateau-phase cells. In the absence of araA, repair of radiation induced DNA damage proceeded with similar kinetics in exponentially growing and plateau-phase cells. AraA at concentrations between 0-1500 μM inhibited DNA repair both in exponentially growing and in plateau-phase cells. However, the degree of inhibition was significantly higher (by a factor of 3) in plateau-phase cells. A similar degree of repair inhibition by araA was observed in plateau-phase cells treated in their conditioned medium, as well as in plateau-phase cells that were transferred in fresh growth medium just before treatment initiation. These results indicate the importance of biochemical parameters associated with alterations in the growth state of the cells for the inhibitory effect of araA and may help in the elucidation of the molecular mechanism(s) underlying repair inhibition by inhibitors of DNA replication. (orig.)

  16. Hb G-Waimanalo [A1] or α64(E13)Asp→Asn (α1) (HBA1: c.193G>A) Observed in a Bulgarian Family.

    Science.gov (United States)

    Petkov, Georgi; Dimishkovska, Marija; Tsoneva Ivanova, Vanya; Yordanov, Georgi; Zdraveski, Alexandar; Plaseska-Karanfilska, Dijana

    2015-01-01

    The abnormal hemoglobin (Hb) with an aspartic acid to asparagine substitution at α64 has been found on both the α2- and α1-globin genes. It has been described in many different populations under different names, but never in Bulgaria. Using the recently proposed nomenclature, Hb G-Waimanalo [A1] refers to the HBA1: c.193G > A, while Hb G-Waimanalo [A2] refers to the HBA2: c.193G > A mutation. Here, we present the first family from Bulgaria with Hb G-Waimanalo [A1].

  17. Radiation effect on boundary layer flow of an Eyring–Powell fluid over an exponentially shrinking sheet

    Directory of Open Access Journals (Sweden)

    Asmat Ara

    2014-12-01

    Full Text Available The aim of this paper was to examine the steady boundary layer flow of an Eyring–Powell model fluid due to an exponentially shrinking sheet. In addition, the heat transfer process in the presence of thermal radiation is considered. Using usual similarity transformations the governing equations have been transformed into non-linear ordinary differential equations. Homotopy analysis method (HAM is employed for the series solutions. The convergence of the obtained series solutions is carefully analyzed. Numerical values of the temperature gradient are presented and discussed. It is observed that velocity increases with an increase in mass suction S. In addition, for the temperature profiles opposite behavior is observed for increment in suction. Moreover, the thermal boundary layer thickness decreases due to increase in Prandtl number Pr and thermal radiation R.

  18. Role of exponential type random invexities for asymptotically sufficient efficiency conditions in semi-infinite multi-objective fractional programming.

    Science.gov (United States)

    Verma, Ram U; Seol, Youngsoo

    2016-01-01

    First a new notion of the random exponential Hanson-Antczak type [Formula: see text]-V-invexity is introduced, which generalizes most of the existing notions in the literature, second a random function [Formula: see text] of the second order is defined, and finally a class of asymptotically sufficient efficiency conditions in semi-infinite multi-objective fractional programming is established. Furthermore, several sets of asymptotic sufficiency results in which various generalized exponential type [Formula: see text]-V-invexity assumptions are imposed on certain vector functions whose components are the individual as well as some combinations of the problem functions are examined and proved. To the best of our knowledge, all the established results on the semi-infinite aspects of the multi-objective fractional programming are new, which is a significantly new emerging field of the interdisciplinary research in nature. We also observed that the investigated results can be modified and applied to several special classes of nonlinear programming problems.

  19. Reduced heme levels underlie the exponential growth defect of the Shewanella oneidensis hfq mutant.

    Directory of Open Access Journals (Sweden)

    Christopher M Brennan

    Full Text Available The RNA chaperone Hfq fulfills important roles in small regulatory RNA (sRNA function in many bacteria. Loss of Hfq in the dissimilatory metal reducing bacterium Shewanella oneidensis strain MR-1 results in slow exponential phase growth and a reduced terminal cell density at stationary phase. We have found that the exponential phase growth defect of the hfq mutant in LB is the result of reduced heme levels. Both heme levels and exponential phase growth of the hfq mutant can be completely restored by supplementing LB medium with 5-aminolevulinic acid (5-ALA, the first committed intermediate synthesized during heme synthesis. Increasing expression of gtrA, which encodes the enzyme that catalyzes the first step in heme biosynthesis, also restores heme levels and exponential phase growth of the hfq mutant. Taken together, our data indicate that reduced heme levels are responsible for the exponential growth defect of the S. oneidensis hfq mutant in LB medium and suggest that the S. oneidensis hfq mutant is deficient in heme production at the 5-ALA synthesis step.

  20. Subcriticality determination of low-enriched UO2 lattices in water by exponential experiment

    International Nuclear Information System (INIS)

    Suzaki, Takenori

    1991-01-01

    To determine the static k (effective neutron multiplication factor) ranging from the critical to an extremely subcritical states, the exponential experiments were performed using various sizes of light-water moderated and reflected low-enriched UO 2 lattice cores. For comparison, the pulsed neutron source experiments were also carried out. In the manner of the Gozani's bracketing method applied to the pulsed source experiment, a formula to obtain k from the measured spatial-decay constant was derived on the basis of diffusion theory. Parameters in the formulas needed to obtain k from the respective experiments were evaluated by 4-group neutron diffusion calculations. The results of the exponential experiments agreed well with those of the pulsed source experiments, the 4-group diffusion calculations and the 137-group Monte Carlo calculations. Therefore, the present data-processing method developed for the exponential experiment was demonstrated to be valid. Besides, through the examination on the parameters used in the data processing, it was found that the dependence of parameter value upon k is weak in the exponential experiment compared with that in the pulsed source experiment. This indicates the superiority of the exponential experiment over the pulsed source experiment for the subcriticality determination of a wide range. (author)

  1. Rank-shaping regularization of exponential spectral analysis for application to functional parametric mapping

    International Nuclear Information System (INIS)

    Turkheimer, Federico E; Hinz, Rainer; Gunn, Roger N; Aston, John A D; Gunn, Steve R; Cunningham, Vincent J

    2003-01-01

    Compartmental models are widely used for the mathematical modelling of dynamic studies acquired with positron emission tomography (PET). The numerical problem involves the estimation of a sum of decaying real exponentials convolved with an input function. In exponential spectral analysis (SA), the nonlinear estimation of the exponential functions is replaced by the linear estimation of the coefficients of a predefined set of exponential basis functions. This set-up guarantees fast estimation and attainment of the global optimum. SA, however, is hampered by high sensitivity to noise and, because of the positivity constraints implemented in the algorithm, cannot be extended to reference region modelling. In this paper, SA limitations are addressed by a new rank-shaping (RS) estimator that defines an appropriate regularization over an unconstrained least-squares solution obtained through singular value decomposition of the exponential base. Shrinkage parameters are conditioned on the expected signal-to-noise ratio. Through application to simulated and real datasets, it is shown that RS ameliorates and extends SA properties in the case of the production of functional parametric maps from PET studies

  2. Using Laguerre polynomials to compute the matrix exponential in burnup calculations

    Energy Technology Data Exchange (ETDEWEB)

    She, D.; Zhu, A.; Wang, K. [Dept. of Engineering Physics, Tsinghua Univ., Beijing, 100084 (China)

    2012-07-01

    An essential part of burnup analysis is to solve the burnup equations. The burnup equations can be regarded as a first-order linear system and solved by means of matrix exponential methods. Because of its large spectrum, it is difficult to compute the exponential of the burnup matrix. Conventional methods of computing the matrix exponential, such as the truncated Taylor expansion and the Pade approximation, are not applicable to burnup calculations. Recently the Chebyshev Rational Approximation Method (CRAM) has been applied to solve burnup matrix exponential and shown to be robust and accurate. However, the main defect of CRAM is that its coefficients are not easy to obtain. In this paper, an orthogonal polynomial expansion method, called Laguerre Polynomial Approximation Method (LPAM), is proposed to compute the matrix exponential in burnup calculations. The polynomial sequence of LPAM can be easily computed in any order and thus LPAM is quite convenient to be utilized into burnup codes. Two typical test cases with the decay and cross-section data taken from the standard ORIGEN 2.1 libraries are calculated for validation, against the reference results provided by CRAM of 14 order. Numerical results show that, LPAM is sufficiently accurate for burnup calculations. The influences of the parameters on the convergence of LPAM are also discussed. (authors)

  3. LMI Approach to Exponential Stability and Almost Sure Exponential Stability for Stochastic Fuzzy Markovian-Jumping Cohen-Grossberg Neural Networks with Nonlinear p-Laplace Diffusion

    Directory of Open Access Journals (Sweden)

    Ruofeng Rao

    2013-01-01

    Full Text Available The robust exponential stability of delayed fuzzy Markovian-jumping Cohen-Grossberg neural networks (CGNNs with nonlinear p-Laplace diffusion is studied. Fuzzy mathematical model brings a great difficulty in setting up LMI criteria for the stability, and stochastic functional differential equations model with nonlinear diffusion makes it harder. To study the stability of fuzzy CGNNs with diffusion, we have to construct a Lyapunov-Krasovskii functional in non-matrix form. But stochastic mathematical formulae are always described in matrix forms. By way of some variational methods in W1,p(Ω, Itô formula, Dynkin formula, the semi-martingale convergence theorem, Schur Complement Theorem, and LMI technique, the LMI-based criteria on the robust exponential stability and almost sure exponential robust stability are finally obtained, the feasibility of which can efficiently be computed and confirmed by computer MatLab LMI toolbox. It is worth mentioning that even corollaries of the main results of this paper improve some recent related existing results. Moreover, some numerical examples are presented to illustrate the effectiveness and less conservatism of the proposed method due to the significant improvement in the allowable upper bounds of time delays.

  4. Resolution characteristics for reflection-mode exponential-doping GaN photocathode.

    Science.gov (United States)

    Wang, Honggang; Qian, Yunsheng; Du, Yujie; Xu, Yuan; Lu, Liubing; Chang, Benkang

    2014-01-20

    According to the expression for modulation transfer function obtained by solving the established 2D continuity equation, the resolution characteristics for reflection-mode exponential-doping and uniform-doping GaN photocathodes have been calculated and comparatively analyzed. These calculated results show that the exponential-doping structure can upgrade not only the resolution capability but also the quantum efficiency for a GaN photocathode. The improvement mechanism is different from the approach for high resolution applied by reducing Te and L(D) or increasing S(V), which leads to low quantum efficiency. The main contribution factor of this improvement is that the mechanism that transports electrons toward the NEA surface is facilitated by the built-in electric field formed by this exponential-doping structure, and the corresponding lateral diffusion is reduced.

  5. Exponential Stability of Time-Switched Two-Subsystem Nonlinear Systems with Application to Intermittent Control

    Directory of Open Access Journals (Sweden)

    Huang Tingwen

    2009-01-01

    Full Text Available This paper studies the exponential stability of a class of periodically time-switched nonlinear systems. Three cases of such systems which are composed, respectively, of a pair of unstable subsystems, of both stable and unstable subsystems, and of a pair of stable systems, are considered. For the first case, the proposed result shows that there exists periodically switching rule guaranteeing the exponential stability of the whole system with (sufficient small switching period if there is a Hurwitz linear convex combination of two uncertain linear systems derived from two subsystems by certain linearization. For the second case, we present two general switching criteria by means of multiple and single Lyapunov function, respectively. We also investigate the stability issue of the third case, and the switching criteria of exponential stability are proposed. The present results for the second case are further applied to the periodically intermittent control. Several numerical examples are also given to show the effectiveness of theoretical results.

  6. An improved super-exponential algorithm for blind equalization of satellite SIMO communication systems

    Science.gov (United States)

    Wu, Dan; Wang, Bing; Gao, Wei; Tan, Weifeng

    2009-12-01

    Blind equalization is an effective way to suppress the inter-symbol interference (ISI), which is caused by multipath fading communication channels. An improved robust super-exponential method (ISEM) is proposed here and extended to single-input multioutput (SIMO) models which are commonly used in satellite communication systems. The method, combining super-exponential method (SEM) and minimum description length (MDL), makes the equalization achieve good results even when the signal to noise ratio (SNR) is low. ISEM estimates the noise power of the received signal and then equalizes it by reducing the noise affection. Compared with robust super-exponential method (RSEM) in [1], the presented method has better performance but less computation.

  7. Exponential discontinuous numerical scheme for electron transport in the continuous slowing down approximation

    International Nuclear Information System (INIS)

    Prinja, A.K.

    1997-01-01

    A nonlinear discretization scheme in space and energy, based on the recently developed exponential discontinuous method, is applied to continuous slowing down dominated electron transport (i.e., in the absence of scattering.) Numerical results for dose and charge deposition are obtained and compared against results from the ONELD and ONEBFP codes, and against exact results from an adjoint Monte Carlo code. It is found that although the exponential discontinuous scheme yields strictly positive and monotonic solutions, the dose profile is considerably straggled when compared to results from the linear codes. On the other hand, the linear schemes produce negative results which, furthermore, do not damp effectively in some cases. A general conclusion is that while yielding strictly positive solutions, the exponential discontinuous method does not show the crude cell accuracy for charged particle transport as was apparent for neutral particle transport problems

  8. Effective Kratzer and Coulomb potentials as limit cases of a multiparameter exponential-type potential

    Energy Technology Data Exchange (ETDEWEB)

    García-Ravelo, J., E-mail: g.ravelo@hotmail.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Menéndez, A.; García-Martínez, J. [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Schulze-Halberg, A. [Department of Mathematics and Actuarial Science and Department of Physics, Indiana University Northwest, 3400 Broadway, Gary, IN 46408 (United States)

    2014-06-13

    We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated.

  9. Few-parameter exponentially correlated wavefunctions for the ground state of lithium

    Science.gov (United States)

    Albert, Victor V.; Guevara, Nicolais L.; Sabin, John R.; Harris, Frank E.

    Compact, but relatively accurate wavefunctions for the ground state of the Li atom were obtained through the use of a limited basis of exponentially correlated functions with optimized nonlinear parameters. In contrast to our earlier work, the basis contains pre-exponential factors that improve the rate of convergence of the basis-set expansion. The matrix elements needed in the present work were evaluated analytically using recursive methods reported recently by one of us; a check on the programming was provided by comparison with numerical evaluations carried out by Turbiner and Guevara. The rate of convergence of the expansion is compared with those of Hylleraas-basis computations, and a comparison is also made with exponentially correlated studies of He-like systems.

  10. Discrete-ordinate method with matrix exponential for a pseudo-spherical atmosphere: Vector case

    International Nuclear Information System (INIS)

    Doicu, A.; Trautmann, T.

    2009-01-01

    The paper is devoted to the extension of the matrix-exponential formalism for the scalar radiative transfer to the vector case. Using basic results of the theory of matrix-exponential functions we provide a compact and versatile formulation of the vector radiative transfer. As in the scalar case, we operate with the concept of the layer equation incorporating the level values of the Stokes vector. The matrix exponentials which enter in the expression of the layer equation are computed by using the matrix eigenvalue method and the Pade approximation. A discussion of the computational efficiency of the proposed method for both an aerosol-loaded atmosphere as well as a cloudy atmosphere is also provided

  11. Exponential dependence of potential barrier height on biased voltages of inorganic/organic static induction transistor

    International Nuclear Information System (INIS)

    Zhang Yong; Yang Jianhong; Cai Xueyuan; Wang Zaixing

    2010-01-01

    The exponential dependence of the potential barrier height φ c on the biased voltages of the inorganic/organic static induction transistor (SIT/OSIT) through a normalized approach in the low-current regime is presented. It shows a more accurate description than the linear expression of the potential barrier height. Through the verification of the numerical calculated and experimental results, the exponential dependence of φ c on the applied biases can be used to derive the I-V characteristics. For both SIT and OSIT, the calculated results, using the presented relationship, are agreeable with the experimental results. Compared to the previous linear relationship, the exponential description of φ c can contribute effectively to reduce the error between the theoretical and experimental results of the I-V characteristics. (semiconductor devices)

  12. Effective Kratzer and Coulomb potentials as limit cases of a multiparameter exponential-type potential

    International Nuclear Information System (INIS)

    García-Ravelo, J.; Menéndez, A.; García-Martínez, J.; Schulze-Halberg, A.

    2014-01-01

    We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated

  13. New exponential synchronization criteria for time-varying delayed neural networks with discontinuous activations.

    Science.gov (United States)

    Cai, Zuowei; Huang, Lihong; Zhang, Lingling

    2015-05-01

    This paper investigates the problem of exponential synchronization of time-varying delayed neural networks with discontinuous neuron activations. Under the extended Filippov differential inclusion framework, by designing discontinuous state-feedback controller and using some analytic techniques, new testable algebraic criteria are obtained to realize two different kinds of global exponential synchronization of the drive-response system. Moreover, we give the estimated rate of exponential synchronization which depends on the delays and system parameters. The obtained results extend some previous works on synchronization of delayed neural networks not only with continuous activations but also with discontinuous activations. Finally, numerical examples are provided to show the correctness of our analysis via computer simulations. Our method and theoretical results have a leading significance in the design of synchronized neural network circuits involving discontinuous factors and time-varying delays. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Spherical Bessel transform via exponential sum approximation of spherical Bessel function

    Science.gov (United States)

    Ikeno, Hidekazu

    2018-02-01

    A new algorithm for numerical evaluation of spherical Bessel transform is proposed in this paper. In this method, the spherical Bessel function is approximately represented as an exponential sum with complex parameters. This is obtained by expressing an integral representation of spherical Bessel function in complex plane, and discretizing contour integrals along steepest descent paths and a contour path parallel to real axis using numerical quadrature rule with the double-exponential transformation. The number of terms in the expression is reduced using the modified balanced truncation method. The residual part of integrand is also expanded by exponential functions using Prony-like method. The spherical Bessel transform can be evaluated analytically on arbitrary points in half-open interval.

  15. Stability of Exponential Euler Method for Stochastic Systems under Poisson White Noise Excitations

    Science.gov (United States)

    Li, Longsuo; Zhang, Yu

    2014-12-01

    The stability of stochastic systems under Poisson white noise excitations which based on the quantum theory is investigated in this paper. In general, the exact solution of the most of the stochastic systems with jumps is not easy to get. So it is very necessary to investigate the numerical solution of equations. On the one hand, exponential Euler method is applied to study stochastic delay differential equations, we can find the sufficient conditions for keeping mean square stability by investigating numerical method of systems. Through the comparison, we get the step-size of this method which is longer than the Euler-Maruyama method. On the other hand, mean square exponential stability of exponential Euler method for semi-linear stochastic delay differential equations under Poisson white noise excitations is confirmed.

  16. State of the art report of exponential experiments with PWR spent nuclear fuel

    International Nuclear Information System (INIS)

    Ro, Seung Gy; Park, Sung Won; Park, Kwang Joon; Kim, Jong Hoon; Hong, Kwon Pyo; Shin, Hee Sung

    2000-09-01

    Exponential experiment method is discussed for verifying the computer code system of the nuclear criticality analysis which makes it possible to apply for the burnup credit in storage, transportation, and handling of spent nuclear fuel. In this report, it is described that the neutron flux density distribution in the exponential experiment system which consists of a PWR spent fuel in a water pool is measured by using 252 Cf neutron source and a mini-fission chamber, and therefrom the exponential decay coefficient is determined. Besides, described is a method for determining the absolute thermal neutron flux density by means of the Cd cut-off technique in association with a gold foil. Also a method is described for analyzing the energy distribution of γ-ray from the gold foil activation detector in detail

  17. Discrete-time recurrent neural networks with time-varying delays: Exponential stability analysis

    Science.gov (United States)

    Liu, Yurong; Wang, Zidong; Serrano, Alan; Liu, Xiaohui

    2007-03-01

    This Letter is concerned with the analysis problem of exponential stability for a class of discrete-time recurrent neural networks (DRNNs) with time delays. The delay is of the time-varying nature, and the activation functions are assumed to be neither differentiable nor strict monotonic. Furthermore, the description of the activation functions is more general than the recently commonly used Lipschitz conditions. Under such mild conditions, we first prove the existence of the equilibrium point. Then, by employing a Lyapunov Krasovskii functional, a unified linear matrix inequality (LMI) approach is developed to establish sufficient conditions for the DRNNs to be globally exponentially stable. It is shown that the delayed DRNNs are globally exponentially stable if a certain LMI is solvable, where the feasibility of such an LMI can be easily checked by using the numerically efficient Matlab LMI Toolbox. A simulation example is presented to show the usefulness of the derived LMI-based stability condition.

  18. Discrete-time recurrent neural networks with time-varying delays: Exponential stability analysis

    International Nuclear Information System (INIS)

    Liu, Yurong; Wang, Zidong; Serrano, Alan; Liu, Xiaohui

    2007-01-01

    This Letter is concerned with the analysis problem of exponential stability for a class of discrete-time recurrent neural networks (DRNNs) with time delays. The delay is of the time-varying nature, and the activation functions are assumed to be neither differentiable nor strict monotonic. Furthermore, the description of the activation functions is more general than the recently commonly used Lipschitz conditions. Under such mild conditions, we first prove the existence of the equilibrium point. Then, by employing a Lyapunov-Krasovskii functional, a unified linear matrix inequality (LMI) approach is developed to establish sufficient conditions for the DRNNs to be globally exponentially stable. It is shown that the delayed DRNNs are globally exponentially stable if a certain LMI is solvable, where the feasibility of such an LMI can be easily checked by using the numerically efficient Matlab LMI Toolbox. A simulation example is presented to show the usefulness of the derived LMI-based stability condition

  19. Additivity of statistical moments in the exponentially modified Gaussian model of chromatography

    International Nuclear Information System (INIS)

    Howerton, Samuel B.; Lee Chomin; McGuffin, Victoria L.

    2002-01-01

    A homologous series of saturated fatty acids ranging from C 10 to C 22 was separated by reversed-phase capillary liquid chromatography. The resultant zone profiles were found to be fit best by an exponentially modified Gaussian (EMG) function. To compare the EMG function and statistical moments for the analysis of the experimental zone profiles, a series of simulated profiles was generated by using fixed values for retention time and different values for the symmetrical (σ) and asymmetrical (τ) contributions to the variance. The simulated profiles were modified with respect to the integration limits, the number of points, and the signal-to-noise ratio. After modification, each profile was analyzed by using statistical moments and an iteratively fit EMG equation. These data indicate that the statistical moment method is much more susceptible to error when the degree of asymmetry is large, when the integration limits are inappropriately chosen, when the number of points is small, and when the signal-to-noise ratio is small. The experimental zone profiles were then analyzed by using the statistical moment and EMG methods. Although care was taken to minimize the sources of error discussed above, significant differences were found between the two methods. The differences in the second moment suggest that the symmetrical and asymmetrical contributions to broadening in the experimental zone profiles are not independent. As a consequence, the second moment is not equal to the sum of σ 2 and τ 2 , as is commonly assumed. This observation has important implications for the elucidation of thermodynamic and kinetic information from chromatographic zone profiles

  20. Enhancement of Visual Field Predictions with Pointwise Exponential Regression (PER) and Pointwise Linear Regression (PLR).

    Science.gov (United States)

    Morales, Esteban; de Leon, John Mark S; Abdollahi, Niloufar; Yu, Fei; Nouri-Mahdavi, Kouros; Caprioli, Joseph

    2016-03-01

    The study was conducted to evaluate threshold smoothing algorithms to enhance prediction of the rates of visual field (VF) worsening in glaucoma. We studied 798 patients with primary open-angle glaucoma and 6 or more years of follow-up who underwent 8 or more VF examinations. Thresholds at each VF location for the first 4 years or first half of the follow-up time (whichever was greater) were smoothed with clusters defined by the nearest neighbor (NN), Garway-Heath, Glaucoma Hemifield Test (GHT), and weighting by the correlation of rates at all other VF locations. Thresholds were regressed with a pointwise exponential regression (PER) model and a pointwise linear regression (PLR) model. Smaller root mean square error (RMSE) values of the differences between the observed and the predicted thresholds at last two follow-ups indicated better model predictions. The mean (SD) follow-up times for the smoothing and prediction phase were 5.3 (1.5) and 10.5 (3.9) years. The mean RMSE values for the PER and PLR models were unsmoothed data, 6.09 and 6.55; NN, 3.40 and 3.42; Garway-Heath, 3.47 and 3.48; GHT, 3.57 and 3.74; and correlation of rates, 3.59 and 3.64. Smoothed VF data predicted better than unsmoothed data. Nearest neighbor provided the best predictions; PER also predicted consistently more accurately than PLR. Smoothing algorithms should be used when forecasting VF results with PER or PLR. The application of smoothing algorithms on VF data can improve forecasting in VF points to assist in treatment decisions.

  1. Randomized OBDDs for the Most Significant Bit of Multiplication Need Exponential Size

    Science.gov (United States)

    Bollig, Beate; Gillé, Marc

    Integer multiplication as one of the basic arithmetic functions has been in the focus of several complexity theoretical investigations and ordered binary decision diagrams (OBDDs) are one of the most common dynamic data structures for Boolean functions. Only two years ago, the question whether the deterministic OBDD complexity of the most significant bit of integer multiplication is exponential has been answered affirmatively. Since probabilistic methods have turned out to be useful in almost all areas of computer science, one may ask whether randomization can help to represent the most significant bit of integer multiplication in smaller size. Here, it is proved that the randomized OBDD complexity is also exponential.

  2. The Exponential Model for the Spectrum of a Time Series: Extensions and Applications

    DEFF Research Database (Denmark)

    Proietti, Tommaso; Luati, Alessandra

    The exponential model for the spectrum of a time series and its fractional extensions are based on the Fourier series expansion of the logarithm of the spectral density. The coefficients of the expansion form the cepstrum of the time series. After deriving the cepstrum of important classes of time...... to the log-spectrum. We then propose two extensions. The first deals with replacing the logarithmic link with a more general Box-Cox link, which encompasses also the identity and the inverse links: this enables nesting alternative spectral estimation methods (autoregressive, exponential, etc.) under the same...

  3. Dynamic topography and gravity anomalies for fluid layers whose viscosity varies exponentially with depth

    Science.gov (United States)

    Revenaugh, Justin; Parsons, Barry

    1987-01-01

    Adopting the formalism of Parsons and Daly (1983), analytical integral equations (Green's function integrals) are derived which relate gravity anomalies and dynamic boundary topography with temperature as a function of wavenumber for a fluid layer whose viscosity varies exponentially with depth. In the earth, such a viscosity profile may be found in the asthenosphere, where the large thermal gradient leads to exponential decrease of viscosity with depth, the effects of a pressure increase being small in comparison. It is shown that, when viscosity varies rapidly, topography kernels for both the surface and bottom boundaries (and hence the gravity kernel) are strongly affected at all wavelengths.

  4. Chaotic SVD method for minimizing the effect of exponential trends in detrended fluctuation analysis

    Science.gov (United States)

    Shang, Pengjian; Lin, Aijing; Liu, Liang

    2009-03-01

    The Detrended Fluctuation Analysis (DFA) and its extensions (MF-DFA) have been used extensively to determine possible long-range correlations in self-affine signals. However, recent studies have reported the susceptibility of DFA to trends which give rise to spurious crossovers and prevent reliable estimation of the scaling exponents. In this study, a smoothing algorithm based on the Chaotic Singular-Value Decomposition (CSVD) is proposed to minimize the effect of exponential trends and distortion in the log-log plots obtained by DFA techniques. The effectiveness of the technique is demonstrated on monofractal and multifractal data corrupted with exponential trends.

  5. Existence and exponential stability of traveling waves for delayed reaction-diffusion systems

    Science.gov (United States)

    Hsu, Cheng-Hsiung; Yang, Tzi-Sheng; Yu, Zhixian

    2018-03-01

    The purpose of this work is to investigate the existence and exponential stability of traveling wave solutions for general delayed multi-component reaction-diffusion systems. Following the monotone iteration scheme via an explicit construction of a pair of upper and lower solutions, we first obtain the existence of monostable traveling wave solutions connecting two different equilibria. Then, applying the techniques of weighted energy method and comparison principle, we show that all solutions of the Cauchy problem for the considered systems converge exponentially to traveling wave solutions provided that the initial perturbations around the traveling wave fronts belong to a suitable weighted Sobolev space.

  6. Special deformed exponential functions leading to more consistent Klauder's coherent states

    International Nuclear Information System (INIS)

    El Baz, M.; Hassouni, Y.

    2001-08-01

    We give a general approach for the construction of deformed oscillators. These ones could be seen as describing deformed bosons. Basing on new definitions of certain quantum series, we demonstrate that they are nothing but the ordinary exponential functions in the limit when the deformation parameters goes to one. We also prove that these series converge to a complex function, in a given convergence radius that we calculate. Klauder's Coherent States are explicitly found through these functions that we design by deformed exponential functions. (author)

  7. On the construction of bivariate exponential distributions with an arbitrary correlation coefficient

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    coefficient (also negative). Secondly, the class satisfies that any linear combination (projection) of the marginal random variables is a phase {type distributions, The latter property is potentially important for the development hypothesis testing in linear models. Thirdly, it is very easy to simulate......In this paper we use a concept of multivariate phase-type distributions to define a class of bivariate exponential distributions. This class has the following three appealing properties. Firstly, we may construct a pair of exponentially distributed random variables with any feasible correlation...

  8. Exponential formula for the reachable sets of quantum stochastic differential inclusions

    International Nuclear Information System (INIS)

    Ayoola, E.O.

    2001-07-01

    We establish an exponential formula for the reachable sets of quantum stochastic differential inclusions (QSDI) which are locally Lipschitzian with convex values. Our main results partially rely on an auxiliary result concerning the density, in the topology of the locally convex space of solutions, of the set of trajectories whose matrix elements are continuously differentiable By applying the exponential formula, we obtain results concerning convergence of the discrete approximations of the reachable set of the QSDI. This extends similar results of Wolenski for classical differential inclusions to the present noncommutative quantum setting. (author)

  9. Parameter estimation of the zero inflated negative binomial beta exponential distribution

    Science.gov (United States)

    Sirichantra, Chutima; Bodhisuwan, Winai

    2017-11-01

    The zero inflated negative binomial-beta exponential (ZINB-BE) distribution is developed, it is an alternative distribution for the excessive zero counts with overdispersion. The ZINB-BE distribution is a mixture of two distributions which are Bernoulli and negative binomial-beta exponential distributions. In this work, some characteristics of the proposed distribution are presented, such as, mean and variance. The maximum likelihood estimation is applied to parameter estimation of the proposed distribution. Finally some results of Monte Carlo simulation study, it seems to have high-efficiency when the sample size is large.

  10. Exponential Speedup of Quantum Annealing by Inhomogeneous Driving of the Transverse Field

    Science.gov (United States)

    Susa, Yuki; Yamashiro, Yu; Yamamoto, Masayuki; Nishimori, Hidetoshi

    2018-02-01

    We show, for quantum annealing, that a certain type of inhomogeneous driving of the transverse field erases first-order quantum phase transitions in the p-body interacting mean-field-type model with and without longitudinal random field. Since a first-order phase transition poses a serious difficulty for quantum annealing (adiabatic quantum computing) due to the exponentially small energy gap, the removal of first-order transitions means an exponential speedup of the annealing process. The present method may serve as a simple protocol for the performance enhancement of quantum annealing, complementary to non-stoquastic Hamiltonians.

  11. Exponential stability of Cohen-Grossberg neural networks with a general class of activation functions

    International Nuclear Information System (INIS)

    Wan Anhua; Wang Miansen; Peng Jigen; Qiao Hong

    2006-01-01

    In this Letter, the dynamics of Cohen-Grossberg neural networks model are investigated. The activation functions are only assumed to be Lipschitz continuous, which provide a much wider application domain for neural networks than the previous results. By means of the extended nonlinear measure approach, new and relaxed sufficient conditions for the existence, uniqueness and global exponential stability of equilibrium of the neural networks are obtained. Moreover, an estimate for the exponential convergence rate of the neural networks is precisely characterized. Our results improve those existing ones

  12. Stochastic exponential stability of the delayed reaction-diffusion recurrent neural networks with Markovian jumping parameters

    International Nuclear Information System (INIS)

    Wang Linshan; Zhang Zhe; Wang Yangfan

    2008-01-01

    Some criteria for the global stochastic exponential stability of the delayed reaction-diffusion recurrent neural networks with Markovian jumping parameters are presented. The jumping parameters considered here are generated from a continuous-time discrete-state homogeneous Markov process, which are governed by a Markov process with discrete and finite state space. By employing a new Lyapunov-Krasovskii functional, a linear matrix inequality (LMI) approach is developed to establish some easy-to-test criteria of global exponential stability in the mean square for the stochastic neural networks. The criteria are computationally efficient, since they are in the forms of some linear matrix inequalities

  13. Effect of Magnetohydrodynamic Couple Stresses on Dynamic Characteristics of Exponential Slider Bearing

    Directory of Open Access Journals (Sweden)

    N.B. Naduvinamani

    2017-05-01

    Full Text Available The effect of couple stresses on static and dynamic characteristics of exponential slider bearing in the presence of magnetic field considering squeeze action is theoretically analyzed in this paper. The modified magnetohydrodynamic couple stress Reynolds type equation is derived on the basis of Stokes couple stress model and closed form expressions are obtained for static and dynamic character coefficients. Comparing with bearing lubricated with non-conducting Newtonian lubricants, the magnetohydrodynamic couple stress lubrication provides the higher steady load carrying capacity, dynamic stiffness and damping coefficient. The exponential bearing shows higher efficiency for small film thickness at higher value of couple stress parameter and Hartmann number.

  14. Einstein, the exponential metric, and a proposed gravitational Michelson-Morley experiment

    International Nuclear Information System (INIS)

    Yilmaz, H.

    1979-01-01

    An early but potentially important remark of Einstein on the exponential nature of time-dilation is discussed. Using the same argument for the length-contraction, plus two alternative kinematical assumptions, the Schwarzschild and exponential metrics are derived. A gravitational Michelson-Morley experiment with one arm directed along the vertical is proposed to test the metrics. The experiment may be considered as a laboratory test of the Schwarzschild field and possibly a test of the black-hole interpretation of collapsed matter

  15. Delay-dependent exponential stability for neural networks with discrete and distributed time-varying delays

    International Nuclear Information System (INIS)

    Zhu Xunlin; Wang Youyi

    2009-01-01

    This Letter studies the exponential stability for a class of neural networks (NNs) with both discrete and distributed time-varying delays. Under weaker assumptions on the activation functions, by defining a more general type of Lyapunov functionals and developing a new convex combination technique, new less conservative and less complex stability criteria are established to guarantee the global exponential stability of the discussed NNs. The obtained conditions are dependent on both discrete and distributed delays, are expressed in terms of linear matrix inequalities (LMIs), and contain fewer decision variables. Numerical examples are given to illustrate the effectiveness and the less conservatism of the proposed conditions.

  16. Discrete-ordinate method with matrix exponential for a pseudo-spherical atmosphere: Scalar case

    International Nuclear Information System (INIS)

    Doicu, A.; Trautmann, T.

    2009-01-01

    We present a discrete-ordinate algorithm using the matrix-exponential solution for pseudo-spherical radiative transfer. Following the finite-element technique we introduce the concept of layer equation and formulate the discrete radiative transfer problem in terms of the level values of the radiance. The layer quantities are expressed by means of matrix exponentials, which are computed by using the matrix eigenvalue method and the Pade approximation. These solution methods lead to a compact and versatile formulation of the radiative transfer. Simulated nadir and limb radiances for an aerosol-loaded atmosphere and a cloudy atmosphere are presented along with a discussion of the model intercomparisons and timings

  17. Stretched-exponential decay functions from a self-consistent model of dielectric relaxation

    International Nuclear Information System (INIS)

    Milovanov, A.V.; Rasmussen, J.J.; Rypdal, K.

    2008-01-01

    There are many materials whose dielectric properties are described by a stretched exponential, the so-called Kohlrausch-Williams-Watts (KWW) relaxation function. Its physical origin and statistical-mechanical foundation have been a matter of debate in the literature. In this Letter we suggest a model of dielectric relaxation, which naturally leads to a stretched exponential decay function. Some essential characteristics of the underlying charge conduction mechanisms are considered. A kinetic description of the relaxation and charge transport processes is proposed in terms of equations with time-fractional derivatives

  18. The non-exponential relaxation of the C60 crystal around glass transition temperature

    International Nuclear Information System (INIS)

    Yan, F; Wang, Y.N.

    1999-01-01

    A model of the energy barrier of a molecule between two orientational states in the C 60 crystal, which depends on the neighboring molecules, is first proposed. Based on this model, the orientational relaxation of C 60 molecules around 90 K was simulated with the Monte Carlo method. The simulation results show that the relaxation is slightly non-exponential and can fit the Kohlrausch-Williams-Watts function with the non-exponential factor β = 0.962 ± 0.002, which is equal to the experimental data that has not been explained before. (orig.)

  19. Rebreathing in the Mapleson A, C and D breathing systems with sinusoidal and exponential flow waveforms.

    Science.gov (United States)

    Cook, L B

    1997-12-01

    The degree of rebreathing in Mapleson A, C and D breathing systems for sinusoidal and exponential flow waveforms is analysed mathematically. The effects of altering the I:E ratio and of introducing an expiratory pause are investigated. The results for sinusoidal waveforms closely resemble those for a square wave. Exponential flow waveforms produce results similar to triangular flow waveforms. The Mapleson A system is always the most efficient. The Mapleson C system is efficient when the I:E ratio is 1:1, becoming less efficient with longer expiration and very inefficient with an expiratory pause. The Mapleson D system becomes efficient when the expiratory pause is long.

  20. Exponential stability of delayed and impulsive cellular neural networks with partially Lipschitz continuous activation functions.

    Science.gov (United States)

    Song, Xueli; Xin, Xing; Huang, Wenpo

    2012-05-01

    The paper discusses exponential stability of distributed delayed and impulsive cellular neural networks with partially Lipschitz continuous activation functions. By relative nonlinear measure method, some novel criteria are obtained for the uniqueness and exponential stability of the equilibrium point. Our method abandons usual assumptions on global Lipschitz continuity, boundedness and monotonicity of activation functions. Our results are generalization and improvement of some existing ones. Finally, two examples and their simulations are presented to illustrate the correctness of our analysis. Copyright © 2012 Elsevier Ltd. All rights reserved.