Alam, Aftab; Johnson, D. D.
2012-04-01
We resolve issues that have plagued reliable prediction of relative phase stability for solid solutions and compounds. Due to its commercially important phase diagram, we showcase the Al-Li system because historically density-functional theory (DFT) results show large scatter and limited success in predicting the structural properties and stability of solid solutions relative to ordered compounds. Using recent advances in an optimal basis-set representation of the topology of electronic charge density (and, hence, atomic size), we present DFT results that agree reasonably well with all known experimental data for the structural properties and formation energies of ordered, off-stoichiometric partially ordered, and disordered alloys, opening the way for reliable study in complex alloys.
M. A. Hussain
2014-01-01
Full Text Available This paper discusses the discrete-time stability analysis of a neural network inverse model control strategy for a relative order two nonlinear system. The analysis is done by representing the closed loop system in state space format and then analyzing the time derivative of the state trajectory using Lyapunov’s direct method. The analysis shows that the tracking output error of the states is confined to a ball in the neighborhood of the equilibrium point where the size of the ball is partly dependent on the accuracy of the neural network model acting as the controller. Simulation studies on the two-tank-in-series system were done to complement the stability analysis and to demonstrate some salient results of the study.
Stability of Fractional Order Switching Systems
HosseinNia, S Hassan; Vinagre, Blas M
2012-01-01
This paper addresses the stabilization issue for fractional order switching systems. Common Lyapunov method is generalized for fractional order systems and frequency domain stability equivalent to this method is proposed to prove the quadratic stability. Some examples are given to show the applicability and effectiveness of the proposed theory.
Continuous first order logic and local stability
Yaacov, Itaï Ben
2008-01-01
We develop continuous first order logic, a variant of the logic described in \\cite{Chang-Keisler:ContinuousModelTheory}. We show that this logic has the same power of expression as the framework of open Hausdorff cats, and as such extends Henson's logic for Banach space structures. We conclude with the development of local stability, for which this logic is particularly well-suited.
Frequency domain stability criteria for fractional-order control systems
无
2006-01-01
This paper concerns about the frequency domain stability criteria for fractional-order control systems. On the base of characteristics of the fractional-order equations solutions, we consider the Nyquist stability criterion in a wider sense and obtain a more common means to analyze the stability of fractional-order systems conveniently. Finally, this paper illustrates the generalized stability criteria with an example to show the effect of the parameters variation on the fractional-order control systems.
Vibrations and Stability - Order & Chaos, Solved Problems
Thomsen, Jon Juel
2002-01-01
A collection of worked out solutions to many of the exercise problems in my textbook "Vibrations and Stability", McGraw-Hill, London, 1997.......A collection of worked out solutions to many of the exercise problems in my textbook "Vibrations and Stability", McGraw-Hill, London, 1997....
Probabilistic robust stabilization of fractional order systems with interval uncertainty.
Alagoz, Baris Baykant; Yeroglu, Celaleddin; Senol, Bilal; Ates, Abdullah
2015-07-01
This study investigates effects of fractional order perturbation on the robust stability of linear time invariant systems with interval uncertainty. For this propose, a probabilistic stability analysis method based on characteristic root region accommodation in the first Riemann sheet is developed for interval systems. Stability probability distribution is calculated with respect to value of fractional order. Thus, we can figure out the fractional order interval, which makes the system robust stable. Moreover, the dependence of robust stability on the fractional order perturbation is analyzed by calculating the order sensitivity of characteristic polynomials. This probabilistic approach is also used to develop a robust stabilization algorithm based on parametric perturbation strategy. We present numerical examples demonstrating utilization of stability probability distribution in robust stabilization problems of interval uncertain systems.
Stability analysis of a class of fractional order nonlinear systems with order lying in (0, 2).
Zhang, Ruoxun; Tian, Gang; Yang, Shiping; Cao, Hefei
2015-05-01
This paper investigates the stability of n-dimensional fractional order nonlinear systems with commensurate order 0 nonlinear systems with order lying in (0, 2). According to this theory, stabilizing a class of fractional order nonlinear systems only need a linear state feedback controller. Simulation results demonstrate the effectiveness of the proposed theory.
Dynamical stability of the holographic system with two competing orders
Du, Yiqiang [School of Physics, University of Chinese Academy of Sciences,Beijing 100049 (China); Lan, Shan-Quan [Department of Physics, Beijing Normal University,Beijing 100875 (China); Tian, Yu [School of Physics, University of Chinese Academy of Sciences,Beijing 100049 (China); State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Science,Beijing 100190 (China); Zhang, Hongbao [Department of Physics, Beijing Normal University,Beijing 100875 (China); Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes,Pleinlaan 2, B-1050 Brussels (Belgium)
2016-01-04
We investigate the dynamical stability of the holographic system with two order parameters, which exhibits competition and coexistence of condensations. In the linear regime, we have developed the gauge dependent formalism to calculate the quasi-normal modes by gauge fixing, which turns out be considerably convenient. Furthermore, by giving different Gaussian wave packets as perturbations at the initial time, we numerically evolve the full nonlinear system until it arrives at the final equilibrium state. Our results show that the dynamical stability is consistent with the thermodynamical stability. Interestingly, the dynamical evolution, as well as the quasi-normal modes, shows that the relaxation time of this model is generically much longer than the simplest holographic system. We also find that the late time behavior can be well captured by the lowest lying quasi-normal modes except for the non-vanishing order towards the single ordered phase. To our knowledge, this exception is the first counter example to the general belief that the late time behavior towards a final stable state can be captured by the lowest lying quasi-normal modes. In particular, a double relation is found for this exception in certain cases.
Fourth order deformed general relativity
Cuttell, Peter D
2014-01-01
Whenever the condition of anomaly freedom is imposed within the framework of effective approaches to loop quantum cosmology, one seems to conclude that a deformation of general covariance is required. Here, starting from a general deformation we regain an effective gravitational Lagrangian including terms up to fourth order in extrinsic curvature. We subsequently constrain the form of the corrections, and then investigate the conditions for the occurrence of a big bounce and the realisation of an inflationary era, in the presence of a perfect fluid or scalar field.
Third-order chromatic dispersion stabilizes Kerr frequency combs
Parra-Rivas, Pedro; Leo, Francois; Coen, Stephane; Gelens, Lendert
2014-01-01
Using numerical simulations of an extended Lugiato-Lefever equation, we analyze the stability and nonlinear dynamics of Kerr frequency combs generated in microresonators and fiber resonators taking into account third-order dispersion effects. We show that cavity solitons underlying Kerr frequency combs, normally sensitive to oscillatory and chaotic instabilities, are stabilized in a wide range of parameter space by third-order dispersion. Moreover, we demonstrate how the snaking structure organizing compound states of multiple cavity solitons is qualitatively changed by third-order dispersion, promoting an increased stability of Kerr combs underlined by a single cavity soliton.
Third-order chromatic dispersion stabilizes Kerr frequency combs.
Parra-Rivas, Pedro; Gomila, Damià; Leo, François; Coen, Stéphane; Gelens, Lendert
2014-05-15
Using numerical simulations of an extended Lugiato-Lefever equation we analyze the stability and nonlinear dynamics of Kerr frequency combs generated in microresonators and fiber resonators, taking into account third-order dispersion effects. We show that cavity solitons underlying Kerr frequency combs, normally sensitive to oscillatory and chaotic instabilities, are stabilized in a wide range of parameter space by third-order dispersion. Moreover, we demonstrate how the snaking structure organizing compound states of multiple cavity solitons is qualitatively changed by third-order dispersion, promoting an increased stability of Kerr combs underlined by a single cavity soliton.
Deriving Laws from Ordering Relations
Knuth, Kevin H.
2004-01-01
The effect of Richard T. Cox's contribution to probability theory was to generalize Boolean implication among logical statements to degrees of implication, which are manipulated using rules derived from consistency with Boolean algebra. These rules are known as the sum rule, the product rule and Bayes Theorem, and the measure resulting from this generalization is probability. In this paper, I will describe how Cox s technique can be further generalized to include other algebras and hence other problems in science and mathematics. The result is a methodology that can be used to generalize an algebra to a calculus by relying on consistency with order theory to derive the laws of the calculus. My goals are to clear up the mysteries as to why the same basic structure found in probability theory appears in other contexts, to better understand the foundations of probability theory, and to extend these ideas to other areas by developing new mathematics and new physics. The relevance of this methodology will be demonstrated using examples from probability theory, number theory, geometry, information theory, and quantum mechanics.
Distributed-Order Dynamic Systems Stability, Simulation, Applications and Perspectives
Jiao, Zhuang; Podlubny, Igor
2012-01-01
Distributed-order differential equations, a generalization of fractional calculus, are of increasing importance in many fields of science and engineering from the behaviour of complex dielectric media to the modelling of nonlinear systems. This Brief will broaden the toolbox available to researchers interested in modeling, analysis, control and filtering. It contains contextual material outlining the progression from integer-order, through fractional-order to distributed-order systems. Stability issues are addressed with graphical and numerical results highlighting the fundamental differences between constant-, integer-, and distributed-order treatments. The power of the distributed-order model is demonstrated with work on the stability of noncommensurate-order linear time-invariant systems. Generic applications of the distributed-order operator follow: signal processing and viscoelastic damping of a mass–spring set up. A new general approach to discretization of distributed-order derivatives and integrals ...
Stability of second-order recurrences modulo pr
Lawrence Somer
2000-01-01
Full Text Available The concept of sequence stability generalizes the idea of uniform distribution. A sequence is p-stable if the set of residue frequencies of the sequence reduced modulo pr is eventually constant as a function of r. The authors identify and characterize the stability of second-order recurrences modulo odd primes.
Certifiable higher order sliding mode control: Practical stability margins approach
Panathula, Chandrasekhara Bharath
The Higher Order Sliding Mode (HOSM) controllers are well known for their robustness/insensitivity to bounded perturbations and for handling any given arbitrary relative degree system. The HOSM controller is to be certified for robustness to unmodeled dynamics, before deploying the controller for practical applications. Phase Margin (PM) and Gain Margin ( GM) are the classical characteristics used in linear systems to quantify the linear controller robustness to unmodeled dynamics, and certain values of these margins are required to certify the controller. These conventional margins (PM and GM) are extended to Practical Stability Phase Margin (PSPM) and Practical Stability Gain Margin (PSGM) in this dissertation, and are used to quantify the HOSM control robustness to unmodeled dynamics, presiding the tool to close the gap for HOSM control certification. The proposed robustness metrics ( PSPM and PSGM) are identified by developing tools/algorithms based on Describing Function-Harmonic Balance method. In order for the HOSM controller to achieve the prescribed values on robustness metrics ( PSPM and PSGM), the HOSM controller is cascaded with a linear compensator. A case study of the application of the proposed metrics (PSPM and PSGM) for the certification of F-16 aircraft HOSM attitude control robustness to cascade unmodeled dynamics is presented. In addition, several simulation examples are presented to verify and to validate the proposed methodology.
First integrals and stability of second-order differential equations
Xu Xue-Jun; Mei Feng-Xiang
2006-01-01
The stability of second-order differential equations is studied by using their integrals. A system of second-order differential equations can be considered as a mechanical system with holonomic constraints. A conserved quantity of the mechanical system or a part of the system is obtained by using the Noether theory. It is possible that the conserved quantity becomes a Liapunov function and the stability of the system is proved by the Liapunov theorem.
Stability Analysis for Stochastic Delayed High-order Neural Networks
无
2006-01-01
In this paper, the global asymptotic stability analysis problem is considered for a class of stochastic high-order neural networks with time-delays. Based on a Lyapunov-Krasovskii functional and the stochastic stability analysis theory, several sufficient conditions are derived in order to guarantee the global asymptotic convergence of the equilibrium point in the mean square. Investigation shows that the addressed stochastic highorder delayed neural networks are globally asymptotically stable in the mean square if there are solutions to some linear matrix inequalities (LMIs). Hence, the global asymptotic stability of the studied stochastic high-order delayed neural networks can be easily checked by the Matlab LMI toolbox. A numerical example is given to demonstrate the usefulness of the proposed global stability criteria.
Ma, Yingdong; Lu, Junguo; Chen, Weidong
2014-03-01
This paper investigates the robust stability and stabilization of fractional order linear systems with positive real uncertainty. Firstly, sufficient conditions for the asymptotical stability of such uncertain fractional order systems are presented. Secondly, the existence conditions and design methods of the state feedback controller, static output feedback controller and observer-based controller for asymptotically stabilizing such uncertain fractional order systems are derived. The results are obtained in terms of linear matrix inequalities. Finally, some numerical examples are given to validate the proposed theoretical results.
A Low Order Theory of Arctic Sea Ice Stability
Moon, W
2011-01-01
We analyze the stability of a low-order coupled sea ice and climate model and extract the essential physics governing the time scales of response as a function of greenhouse gas forcing. Under present climate conditions the stability is controlled by longwave radiation driven heat conduction. However, as greenhouse gas forcing increases and the ice cover decays, the destabilizing influence of ice-albedo feedback acts on equal footing with longwave stabilization. Both are seasonally out of phase and as the system warms towards a seasonal ice state these effects, which underlie the bifurcations between climate states, combine to extend the intrinsic relaxation time scale from ~ 2 yr to 5 yr.
Dynamical stability of the Holographic System with Two Competing Orders
Du, Yiqiang; Tian, Yu; Zhang, Hongbao
2016-01-01
We investigate the dynamical stability of the holographic system with two order parameters, which exhibits competition and coexistence of condensations. In the linear regime, we have developed the gauge dependent formalism to calculate the quasi-normal modes by gauge fixing, which turns out be considerably convenient. Furthermore, by giving different Gaussian wave packets as perturbations at the initial time, we numerically evolve the full nonlinear system until it arrives at the final equilibrium state. Our results show that the dynamical stability is consistent with the thermodynamical stability. Interestingly, the dynamical evolution, as well as the quasi-normal modes, shows that the relaxation time of this model is generically much longer than the simplest holographic system. We also find that the late time behavior can be well captured by the lowest lying quasi-normal modes except for the non-vanishing order towards the single ordered phase. To our knowledge, this exception is the first counter example t...
On higher order relations in Fedosov supermanifolds
Lavrov, P M; Radchenko, O V [Tomsk State Pedagogical University, 634041 Tomsk (Russian Federation)
2006-05-26
Higher order relations existing in normal coordinates between affine extensions of the symplectic curvature tensor and basic objects for any Fedosov supermanifolds are derived. Representation of these relations in general coordinates is discussed.
Higher order relations in Fedosov supermanifolds
Lavrov, P M
2005-01-01
Higher order relations existing in normal coordinates between affine extensions of the curvature tensor and basic objects for any Fedosov supermanifolds are derived. Representation of these relations in general coordinates is discussed.
Bidimensional Relations for Reading Order Detection
Aiello, Marco; Smeulders, Arnold M.W.
2003-01-01
We use a propositional language of qualitative rectangle relations to detect the reading order from document images. Document encoding rules are introduced and, expressed in the propositional language of rectangles, are used to build a reading order detector for document images. Results of testing t
Stabilization of third-order bilinear systems using constant controls
A. E. Golubev
2014-01-01
Full Text Available This paper deals with the zero equilibrium stabilization for dynamical systems that have control input singularities. A dynamical system with scalar control input is called nonregular if the coefficient of input becomes null on a subset of the phase space that contains the origin. One of the classes of nonregular dynamical systems is represented by bilinear systems. In case of second-order bilinear systems the necessary and sufficient conditions for the zero equilibrium stabilizability are known in the literature. However, in general case the stabilization problem in the presence of control input singularities has not been solved yet.In this note we solve the problem of the zero equilibrium stabilization for the third-order bilinear dynamical systems given in a canonical form. The solution is found in the class of constant controls. The necessary and sufficient conditions are obtained for the zero equilibrium stabilizability of the bilinear systems in question.The dependence of the zero equilibrium stabilizability on system parameter values is analyzed. The general criteria of stabilizability by means of constant controls are given for the bilinear systems in question. In case when all the system parameters have nonzero values the necessary and sufficient stabilizability conditions are proved. The case when some of the parameters are equal to zero is also considered.Further research can be focused on extending the obtained results to a higher-order case of bilinear and affine dynamical systems. The solution of the considered stabilization problem should also be found not only within constant controls but also in a class of state feedbacks, particularly, in the case when stabilizing constant control does not exist.One of the potential application areas for the obtained theoretical results is automatic control of technical plants like unmanned aerial vehicles and mobile robots.
Stability and convergence of a higher order rational difference Equation
Gazor, Hamid
2011-01-01
In this paper the asymptotic stability of equilibria and periodic points of the following higher order rational difference Equation x_{n+1} =(alpha x_{n-k})/(1+x_{n}...x_{n-k}), k>=1, n=0,1,... is studied where the parameters ?alpha, betta, and gamma are positive real numbers, and the initial conditions x_{-k}, ..., x_{0} are given arbitrary real numbers. The forbidden set of this equation is found and then, the order reduction method is used to facilitate the analysis of its asymptotic dynamics
Tourism versus spatial order: mutual relations
Meyer, Beata
2012-01-01
The relation between tourism and the spatial environment is characterized by mutual interaction. The proliferation of tourism and massive tourism development intensifies its impact on the spatial environment, yet the focus is usually placed on environmental degradation and the resulting distortion of spatial order. Concurrently, the significance of the spatial environment, and spatial order in particular, as one of the determinants of tourism development is understated. On a theoretical plane...
Time-Discrete Higher-Order ALE Formulations: Stability
Bonito, Andrea
2013-01-01
Arbitrary Lagrangian Eulerian (ALE) formulations deal with PDEs on deformable domains upon extending the domain velocity from the boundary into the bulk with the purpose of keeping mesh regularity. This arbitrary extension has no effect on the stability of the PDE but may influence that of a discrete scheme. We examine this critical issue for higher-order time stepping without space discretization. We propose time-discrete discontinuous Galerkin (dG) numerical schemes of any order for a time-dependent advection-diffusion-model problem in moving domains, and study their stability properties. The analysis hinges on the validity of the Reynold\\'s identity for dG. Exploiting the variational structure and assuming exact integration, we prove that our conservative and nonconservative dG schemes are equivalent and unconditionally stable. The same results remain true for piecewise polynomial ALE maps of any degree and suitable quadrature that guarantees the validity of the Reynold\\'s identity. This approach generalizes the so-called geometric conservation law to higher-order methods. We also prove that simpler Runge-Kutta-Radau methods of any order are conditionally stable, that is, subject to a mild ALE constraint on the time steps. Numerical experiments corroborate and complement our theoretical results. © 2013 Society for Industrial and Applied Mathematics.
Beyond Special Relativity at second order
Carmona, J M; Relancio, J J
2016-01-01
The study of generic, non-linear, deformations of Special Relativity parametrized by a high-energy scale $M$, which was carried out at first order in $M$ in Phys.Rev. D86, 084032 (2012), is extended to second order. This can be done systematically through a ('generalized') change of variables from momentum variables that transform linearly. We discuss the different perspectives on the meaning of the change of variables, obtain the coefficients of modified composition laws and Lorentz transformations at second order, and work out how $\\kappa$-Poincar\\'e, the most commonly used example in the literature, is reproduced as a particular case of the generic framework exposed here.
Dynamic Stability Analysis Using High-Order Interpolation
Juarez-Toledo C.
2012-10-01
Full Text Available A non-linear model with robust precision for transient stability analysis in multimachine power systems is proposed. The proposed formulation uses the interpolation of Lagrange and Newton's Divided Difference. The High-Order Interpolation technique developed can be used for evaluation of the critical conditions of the dynamic system.The technique is applied to a 5-area 45-machine model of the Mexican interconnected system. As a particular case, this paper shows the application of the High-Order procedure for identifying the slow-frequency mode for a critical contingency. Numerical examples illustrate the method and demonstrate the ability of the High-Order technique to isolate and extract temporal modal behavior.
Stability of ordered phases in block copolymer melts and solutions
Kell Mortensen
2008-11-01
Block copolymer melts and solutions assemble into nanosized objects that order into a variety of phases, depending on molecular parameters and mutual interactions. Beyond the classical phases of lamella ordered sheets, hexagonally ordered cylinders and cubic ordered spheres, the complex bicontinuous gyroid phase and the modulated lamellar phase are observed near the phase boundaries. The stability of these phases has been discussed on the basis of theoretical calculations. Here, we will discuss new experimental results showing that the given ordered phase depends critically on both molecular purity and mechanical treatment of the sample. While a variety of block copolymer micellar systems have been shown to undergo the liquid-to-bcc-to-fcc phase sequence upon varying micellar parameters (or temperature), we find for a purified system a different sequence, namely liquid-to-fcc-to-bcc [1]. The latter sequence is by the way the one predicted for pure block copolymer melts. External fields like shear or stress may also affect the ordered phase. Applying well-controlled large-amplitude oscillatory shear can be used to effectively control the texture of soft materials in the ordered states. As an example, we present results on a body-centred-cubic phase of a block copolymer system, showing how a given texture can be controlled with the application of specific shear rate and shear amplitude [2,3]. Shear may however also affect the thermodynamic ground state, causing shear-induced ordering and disordering (melting), and shear-induced order–order transitions. We will present data showing that the gyroid state of diblock copolymer melts is unstable when exposed to large amplitude/frequency shear, transforming into the hexagonal cylinder phase [4]. The transformation is completely reversible. With the rather slow kinetics in the transformation of copolymer systems, it is possible in detail to follow the complex transformation process, where we find transient ordered
Introduction: interregional relations in the world order
Jordi Bacaria
2015-09-01
Full Text Available This article will analyse factors which, since the end of last century, have made interregional relations very important to understand the world geopolitical and economic order. Interregional relations are defined as those which pertain to relations between regions or between a given state and a given region, or within a megaregion. This evolution results from: the growing demand in the emerging economies and the interaction among them, a new framework of interregional economic relations, and the development of new commercial channels. Finally, this paper will introduce the different articled included in this issue.
Polymer quantization, stability and higher-order time derivative terms
Cumsille, Patricio; Ossandon, Sebastian; Reyes, Camilo
2015-01-01
The stability of higher-order time derivative theories using the polymer extension of quantum mechanics is studied. First, we focus on the well-known Pais-Uhlenbeck model and by casting the theory into the sum of two decoupled harmonic oscillators we show that the energy spectrum is composed with positive and negative energy parts. The Schrodinger quantization of the model with creation and annihilations operators leads to a theory with unbounded Hamiltonian that can be interpreted in terms of normal particles and Lee-Wick-like particles responsible for the instability. We investigate whether the fundamental discreetness implicit in the polymer quantization can regularize the effects of the negative energies introduced by the Lee-Wick-like particles which are associated to a high-energy scale. Precisely, we show that the polymer quantization leads to a positive defined Hamiltonian whose stability is improved as the number of Lee-Wick-like particles grows.
REGULAR RELATIONS AND MONOTONE NORMAL ORDERED SPACES
XU XIAOQUAN; LIU YINGMING
2004-01-01
In this paper the classical theorem of Zareckii about regular relations is generalized and an intrinsic characterization of regularity is obtained. Based on the generalized Zareckii theorem and the intrinsic characterization of regularity, the authors give a characterization of monotone normality of ordered spaces. A new proof of the UrysohnNachbin lemma is presented which is quite different from the classical one.
Polyunsaturated Lipids Regulate Membrane Domain Stability by Tuning Membrane Order.
Levental, Kandice R; Lorent, Joseph H; Lin, Xubo; Skinkle, Allison D; Surma, Michal A; Stockenbojer, Emily A; Gorfe, Alemayehu A; Levental, Ilya
2016-04-26
The plasma membrane (PM) serves as the functional interface between a cell and its environment, hosting extracellular signal transduction and nutrient transport among a variety of other processes. To support this extensive functionality, PMs are organized into lateral domains, including ordered, lipid-driven assemblies termed lipid rafts. Although the general requirements for ordered domain formation are well established, how these domains are regulated by cell-endogenous mechanisms or exogenous perturbations has not been widely addressed. In this context, an intriguing possibility is that dietary fats can incorporate into membrane lipids to regulate the properties and physiology of raft domains. Here, we investigate the effects of polyunsaturated fats on the organization of membrane domains across a spectrum of membrane models, including computer simulations, synthetic lipid membranes, and intact PMs isolated from mammalian cells. We observe that the ω-3 polyunsaturated fatty acid docosahexaenoic acid is robustly incorporated into membrane lipids, and this incorporation leads to significant remodeling of the PM lipidome. Across model systems, docosahexaenoic acid-containing lipids enhance the stability of ordered raft domains by increasing the order difference between them and coexisting nonraft domains. The relationship between interdomain order disparity and the stability of phase separation holds for a spectrum of different perturbations, including manipulation of cholesterol levels and high concentrations of exogenous amphiphiles, suggesting it as a general feature of the organization of biological membranes. These results demonstrate that polyunsaturated fats affect the composition and organization of biological membranes, suggesting a potential mechanism for the extensive effects of dietary fat on health and disease.
Boundary-bulk relation in topological orders
Liang Kong
2017-09-01
Full Text Available In this paper, we study the relation between an anomaly-free n+1D topological order, which are often called n+1D topological order in physics literature, and its nD gapped boundary phases. We argue that the n+1D bulk anomaly-free topological order for a given nD gapped boundary phase is unique. This uniqueness defines the notion of the “bulk” for a given gapped boundary phase. In this paper, we show that the n+1D “bulk” phase is given by the “center” of the nD boundary phase. In other words, the geometric notion of the “bulk” corresponds precisely to the algebraic notion of the “center”. We achieve this by first introducing the notion of a morphism between two (potentially anomalous topological orders of the same dimension, then proving that the notion of the “bulk” satisfies the same universal property as that of the “center” of an algebra in mathematics, i.e. “bulk = center”. The entire argument does not require us to know the precise mathematical description of a (potentially anomalous topological order. This result leads to concrete physical predictions.
Assessing Stability and Change in a Second-Order Confirmatory Factor Model of Meaning in Life.
Krause, Neal; Hayward, R David
2014-04-01
Research indicates that meaning in life is an important correlate of health and well-being. However, relatively little is known about the way a sense of meaning may change over time. The purpose of this study is to explore two ways of assessing change in meaning within a second-order confirmatory factor analysis framework. First, tests are conducted to see if the first and second-order factor loadings and measurement error terms are invariant over time. Second, a largely overlooked technique is used to assess change and stability in meaning at the second-order level. Findings from a nationwide survey reveal that the first and second-order factor loadings are invariant of time. Moreover, the second-order measurement error terms, but not the first-order measurement error terms, are invariant, as well. The results further reveal that standard ways of assessing stability mask significant change in meaning that is due largely to regression to the mean.
Research on the stability of control systems described by fractional-order transfer functions
Zeng Qingshan; Zhu Xinjian; Cao Guangyi
2005-01-01
The stability of control systems described by fractional-order transfer function form is mainly investigated. The stability analysis of integer-order linear systems was extended to the fractional-order control systems. The stability definition of fractional-order linear control systems is presented in terms of the Lyapunov's stability theory. Using the theorems of the Mittag-Leffler function in two parameters directly derives the stability conclusion. The illustrative examples are also given by simulation results.
Strong Stability Preserving Explicit Runge--Kutta Methods of Maximal Effective Order
Hadjimichael, Yiannis
2013-07-23
We apply the concept of effective order to strong stability preserving (SSP) explicit Runge--Kutta methods. Relative to classical Runge--Kutta methods, methods with an effective order of accuracy are designed to satisfy a relaxed set of order conditions but yield higher order accuracy when composed with special starting and stopping methods. We show that this allows the construction of four-stage SSP methods with effective order four (such methods cannot have classical order four). However, we also prove that effective order five methods---like classical order five methods---require the use of nonpositive weights and so cannot be SSP. By numerical optimization, we construct explicit SSP Runge--Kutta methods up to effective order four and establish the optimality of many of them. Numerical experiments demonstrate the validity of these methods in practice.
Doungmo Goufo, Emile Franc
2016-08-21
A more generalized approach, the concept of variable order derivative, is used to study the well-known replicator-mutator dynamics taking place in a moving medium. The biological relevance of the variable order context is explored via the language learning in social groups and stability of fixed points for the generalized model is recalled and discussed. Related graphs are plotted for different values of the derivative order γ. It happens that the threshold condition for learning accuracy symbolized by a function of payoff is a monotonically increasing function irrespective of the value of the time derivative order. Also, the limit cycles and their amplitudes are shown to vary with the value of the derivative order γ. These amplitudes become bigger as γ grows but the stability of the system is not affected. The generalized model, namely the variable order replicator-mutator dynamics in a moving medium is numerically solved via Crank-Nicholson scheme whose stability and convergence results are provided in details. An application to a variable order replicator-mutator dynamics of a population with three strategies is presented and numerical simulations are performed for some fixed values of the position variable r and the grid points. They display limit cycles appearing and disappearing in function of the values of the position r. The amplitudes of limit cycles are also proved to proportionally depend on r and the stability of the system remains unaffected. This shows the impressive effect of the transport process on the bifurcation dynamics of the model.
Electret Stability Related to Spherulites in Polypropylene
Thyssen, Anders; Almdal, Kristoffer; Thomsen, Erik Vilain
2015-01-01
Electret charge stability has been related to the size of the spherulites in polypropylene. As the size of the spherulites is decreased the stability is increased. This is seen for isothermal conditions at 90 °C and 120 °C as well as for 90 % relative humidity at 50 °C. The charge release...... temperature is also increased in thermally stimulated voltage discharge experiments as the size of the spherulites is decreased. The size of the spherulites is controlled though the cooling rate from polypropylenes liquid state....
Uniform stability of displacement coupled second-order equations
Abdelaziz Soufyane
2001-04-01
Full Text Available We prove that the uniform stability of semigroups associated to displacement coupled dissipator systems is equivalent to the uniform stability of velocity coupled dissipator systems. Using this equivalence, we give sufficient conditions for obtaining uniform stability and exact controllability of displacement coupled dissipator systems.
STABILITY CRITERIA FOR STOCHASTIC DISCRETE-TIME FRACTIONAL ORDER SYSTEMS
Carmen BARBACIORU
2016-05-01
Full Text Available In this paper are discussed stability problems for a class of discrete-time fractional systems (DTFSs with independent random perturbations. Two notions of mean square stability (MSS and mean square asymptotic stability (MSAS are introduced for the DTFSs by using an approximating linear stochastic system. Necessary and sufficient conditions for MSS and MSA are then derived.
Stability of relative equilibria of three vortices
Aref, Hassan
2009-01-01
for the three eigenvalues determining the stability, including a new formula for the angular velocity of rotation of a collinear relative equilibrium. A graphical representation of the space of vortex circulations is introduced, and the resultants between various polynomials that enter the problem are used...
Gottlieb, Sigal
2015-04-10
High order spatial discretizations with monotonicity properties are often desirable for the solution of hyperbolic PDEs. These methods can advantageously be coupled with high order strong stability preserving time discretizations. The search for high order strong stability time-stepping methods with large allowable strong stability coefficient has been an active area of research over the last two decades. This research has shown that explicit SSP Runge-Kutta methods exist only up to fourth order. However, if we restrict ourselves to solving only linear autonomous problems, the order conditions simplify and this order barrier is lifted: explicit SSP Runge-Kutta methods of any linear order exist. These methods reduce to second order when applied to nonlinear problems. In the current work we aim to find explicit SSP Runge-Kutta methods with large allowable time-step, that feature high linear order and simultaneously have the optimal fourth order nonlinear order. These methods have strong stability coefficients that approach those of the linear methods as the number of stages and the linear order is increased. This work shows that when a high linear order method is desired, it may still be worthwhile to use methods with higher nonlinear order.
A class of high-order Runge-Kutta-Chebyshev stability polynomials
O'Sullivan, Stephen
2015-01-01
The analytic form of a new class of factorized Runge-Kutta-Chebyshev (FRKC) stability polynomials of arbitrary order $N$ is presented. Roots of FRKC stability polynomials of degree $L = MN$ are used to construct explicit schemes comprising $L$ forward Euler stages with internal stability ensured through a sequencing algorithm which limits the internal amplification factors to $\\sim L^2$. The associated stability domain scales as $M^2$ along the real axis. Marginally stable real-valued points on the interior of the stability domain are removed via a prescribed damping procedure. By construction, FRKC schemes meet all linear order conditions; for nonlinear problems at orders above 2, complex splitting or Butcher group composition methods are required. Linear order conditions of the FRKC stability polynomials are verified at orders 2, 4, and 6 in numerical experiments. Comparative studies with existing methods show the second-order unsplit FRKC2 scheme and higher order (4 and 6) split FRKC schemes are efficient ...
48 CFR 2413.505 - Purchase order and related forms.
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Purchase order and related... DEVELOPMENT CONTRACTING METHODS AND CONTRACTING TYPES SIMPLIFIED ACQUISITION PROCEDURES Purchase Orders 2413.505 Purchase order and related forms....
Mechanical stability of ordered droplet packings in microfluidic channels
Fleury, Jean-Baptiste; Claussen, Ohle; Herminghaus, Stephan; Brinkmann, Martin; Seemann, Ralf
2011-12-01
The mechanical response and stability of one and two-row packing of monodisperse emulsion droplets are studied in quasi 2d microchannels under longitudinal compression. Depending on the choice of parameter, a considered droplet arrangement is either transformed continuously into another packing under longitudinal compression or becomes mechanically unstable and segregates into domains of higher and lower packing fraction. Our experimental results are compared to analytical calculations for 2d-droplet arrangements with good quantitative agreement. This study also predicts important consequences for the stability of droplet arrangements in flowing systems.
Stability analysis of impulsive functional systems of fractional order
Stamova, Ivanka; Stamov, Gani
2014-03-01
In this paper, a class of impulsive fractional functional differential systems is investigated. Sufficient conditions for stability of the zero solution are proved, extending the corresponding theory of impulsive functional differential equations. The investigations are carried out by using the comparison principle, coupled with the Lyapunov function method. We apply our results to an impulsive single species model of Lotka-Volterra type.
Compositional ordering and stability in nanostructured, bulk thermoelectric alloys.
Hekmaty, Michelle A.; Faleev, S.; Medlin, Douglas L.; Leonard, F.; Lensch-Falk, J.; Sharma, Peter Anand; Sugar, J. D.
2009-09-01
Thermoelectric materials have many applications in the conversion of thermal energy to electrical power and in solid-state cooling. One route to improving thermoelectric energy conversion efficiency in bulk material is to embed nanoscale inclusions. This report summarize key results from a recently completed LDRD project exploring the science underpinning the formation and stability of nanostructures in bulk thermoelectric and the quantitative relationships between such structures and thermoelectric properties.
Stability of the second order partial differential equations
Ghaemi MB; Cho YJ; Alizadeh B; Gordji M Eshaghi
2011-01-01
Abstract We say that a functional equation (ξ) is stable if any function g satisfying the functional equation (ξ) approximately is near to a true solution of (ξ). In this paper, by using Banach's contraction principle, we prove the stability of nonlinear partial differential equations of the following forms: y x ( x , t ) = f ( x , t , y ( x , t ) ) , a y x ( x , t ) + b y t ( x , t ) = f ( x , t , y ( x , t ) ) , p (...
Stability of the second order partial differential equations
Ghaemi MB
2011-01-01
Full Text Available Abstract We say that a functional equation (ξ is stable if any function g satisfying the functional equation (ξ approximately is near to a true solution of (ξ. In this paper, by using Banach's contraction principle, we prove the stability of nonlinear partial differential equations of the following forms: y x ( x , t = f ( x , t , y ( x , t , a y x ( x , t + b y t ( x , t = f ( x , t , y ( x , t , p ( x , t y x t ( x , t + q ( x , t y t ( x , t + p t ( x , t y x ( x , t - p x ( x , t y t ( x , t = f ( x , t , y ( x , t , p ( x , t y x x ( x , t + q ( x , t y x ( x , t = f ( x , t , y ( x , t . 2000 Mathematics Subject Classification. 26D10; 34K20; 39B52; 39B82; 46B99.
Deniz, Furkan Nur; Alagoz, Baris Baykant; Tan, Nusret; Atherton, Derek P
2016-05-01
This paper introduces an integer order approximation method for numerical implementation of fractional order derivative/integrator operators in control systems. The proposed method is based on fitting the stability boundary locus (SBL) of fractional order derivative/integrator operators and SBL of integer order transfer functions. SBL defines a boundary in the parametric design plane of controller, which separates stable and unstable regions of a feedback control system and SBL analysis is mainly employed to graphically indicate the choice of controller parameters which result in stable operation of the feedback systems. This study reveals that the SBL curves of fractional order operators can be matched with integer order models in a limited frequency range. SBL fitting method provides straightforward solutions to obtain an integer order model approximation of fractional order operators and systems according to matching points from SBL of fractional order systems in desired frequency ranges. Thus, the proposed method can effectively deal with stability preservation problems of approximate models. Illustrative examples are given to show performance of the proposed method and results are compared with the well-known approximation methods developed for fractional order systems. The integer-order approximate modeling of fractional order PID controllers is also illustrated for control applications.
48 CFR 1513.505 - Purchase order and related forms.
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Purchase order and related... CONTRACTING METHODS AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Purchase Orders 1513.505 Purchase order and related forms. Contracting Officers may use the EPA Form 1900-8, Procurement Request/Order,...
Stability analysis of fractional-order Hopfield neural networks with time delays.
Wang, Hu; Yu, Yongguang; Wen, Guoguang
2014-07-01
This paper investigates the stability for fractional-order Hopfield neural networks with time delays. Firstly, the fractional-order Hopfield neural networks with hub structure and time delays are studied. Some sufficient conditions for stability of the systems are obtained. Next, two fractional-order Hopfield neural networks with different ring structures and time delays are developed. By studying the developed neural networks, the corresponding sufficient conditions for stability of the systems are also derived. It is shown that the stability conditions are independent of time delays. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results obtained in this paper.
LMI Conditions for Global Stability of Fractional-Order Neural Networks.
Zhang, Shuo; Yu, Yongguang; Yu, Junzhi
2016-08-02
Fractional-order neural networks play a vital role in modeling the information processing of neuronal interactions. It is still an open and necessary topic for fractional-order neural networks to investigate their global stability. This paper proposes some simplified linear matrix inequality (LMI) stability conditions for fractional-order linear and nonlinear systems. Then, the global stability analysis of fractional-order neural networks employs the results from the obtained LMI conditions. In the LMI form, the obtained results include the existence and uniqueness of equilibrium point and its global stability, which simplify and extend some previous work on the stability analysis of the fractional-order neural networks. Moreover, a generalized projective synchronization method between such neural systems is given, along with its corresponding LMI condition. Finally, two numerical examples are provided to illustrate the effectiveness of the established LMI conditions.
Loop Entropy Assists Tertiary Order: Loopy Stabilization of Stacking Motifs
Daniel P. Aalberts
2011-11-01
Full Text Available The free energy of an RNA fold is a combination of favorable base pairing and stacking interactions competing with entropic costs of forming loops. Here we show how loop entropy, surprisingly, can promote tertiary order. A general formula for the free energy of forming multibranch and other RNA loops is derived with a polymer-physics based theory. We also derive a formula for the free energy of coaxial stacking in the context of a loop. Simulations support the analytic formulas. The effects of stacking of unpaired bases are also studied with simulations.
Stability of permeative flows in 1 dimensionally ordered systems
Prost, J.; Pomeau, Y.; Guyon, E.
1991-03-01
Layered structures are met in dissipative systems, such as Rayleigh Bénard rolls, as well as in liquid crystalline phases (smectics and cholesterics). We present here a general description, in the framework of phase dynamics, of the stability of these structures when submitted to an external force field (flow, electric field) acting perpendicular to the roll axis for various boundary conditions. The one-dimensional equilibrium solution with fixed boundary conditions leads to an effect, discovered experimentally by Pocheau and Croquette on Rayleigh-Bérnard rolls in the presence of a transverse flow, and involving the coexistence of compressed and dilated rolls; this effect has a known counterpart in cholesterics. Using the same boundary conditions, we generalize the well known undulation instability obtained under a dilative stress to the case of the action of a transverse force both from the point of view of linear stability and in the highly nonlinear limit. The possibility of observing fractal structures is indicated. For mixed boundary conditions, it is possible to have a sustained time dependent behavior involving the nucleation of new layers as also observed in the above mentioned experiments. On rencontre des structures en couches dans des systèmes dissipatifs tels que les rouleaux convectifs de Rayleigh-Bénard et dans les cristaux liquides (smectiques et cholestériques). Nous présentons ici une description générale de la stabilité de ces structures dans le cadre du formalisme de la diffusion de phase, lorsqu'elles sont soumises à un champ de force extérieur (écoulement, champ électrique) agissant à angle droit de la direction des rouleaux, en fonction des conditions aux limites. La solution unidimensionnelle d'équilibre avec des conditions aux limites rigides pour la phase conduit à un effet découvert par Pocheau et Croquette (P.C.) dans la convection de R.B. et mettant en jeu la coexistence de zones dilatée et comprimée. Cet effet a un
Preservation of Stability and Synchronization of a Class of Fractional-Order Systems
2012-01-01
We present sufficient conditions for the preservation of stability of fractional-order systems, and then we use this result to preserve the synchronization, in a master-slave scheme, of fractional-order systems. The systems treated herein are autonomous fractional differential linear and nonlinear systems with commensurate orders lying between 0 and 2, where the nonlinear ones can be described as a linear part plus a nonlinear part. These results are based on stability properties for equilibr...
Robust Stability of Fractional Order Time-Delay Control Systems: A Graphical Approach
Radek Matušů; Roman Prokop
2015-01-01
The paper deals with a graphical approach to investigation of robust stability for a feedback control loop with an uncertain fractional order time-delay plant and integer order or fractional order controller. Robust stability analysis is based on plotting the value sets for a suitable range of frequencies and subsequent verification of the zero exclusion condition fulfillment. The computational examples present the typical shapes of the value sets of a family of closed-loop characteristic qua...
48 CFR 1913.505 - Purchase order and related forms.
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Purchase order and related... CONTRACTING METHODS AND CONTRACT TYPES SMALL PURCHASES AND OTHER SIMPLIFIED PURCHASE PROCEDURES Purchase Orders 1913.505 Purchase order and related forms....
Stabilization and PID tuning algorithms for second-order unstable processes with time-delays.
Seer, Qiu Han; Nandong, Jobrun
2017-03-01
Open-loop unstable systems with time-delays are often encountered in process industry, which are often more difficult to control than stable processes. In this paper, the stabilization by PID controller of second-order unstable processes, which can be represented as second-order deadtime with an unstable pole (SODUP) and second-order deadtime with two unstable poles (SODTUP), is performed via the necessary and sufficient criteria of Routh-Hurwitz stability analysis. The stability analysis provides improved understanding on the existence of a stabilizing range of each PID parameter. Three simple PID tuning algorithms are proposed to provide desired closed-loop performance-robustness within the stable regions of controller parameters obtained via the stability analysis. The proposed PID controllers show improved performance over those derived via some existing methods.
Stability Analysis for Fractional-Order Linear Singular Delay Differential Systems
Hai Zhang
2014-01-01
Full Text Available We investigate the delay-independently asymptotic stability of fractional-order linear singular delay differential systems. Based on the algebraic approach, the sufficient conditions are presented to ensure the asymptotic stability for any delay parameter. By applying the stability criteria, one can avoid solving the roots of transcendental equations. An example is also provided to illustrate the effectiveness and applicability of the theoretical results.
Héctor Armando Durán Peralta
2010-04-01
Full Text Available The stability of reactors having encompassing concentration and temperature parameters, such as continuous flow stirred tank reactors (CSTR, has been widely explored in the literature; however, there are few papers about the stability of tubular reactor having distributed spatial concentration and temperature parameters such as the plow flow tubular reactor (PFTR. This paper analyses the stability of isothermal and non-isothermal PFTR reactors using the Lyapunov functional method. The first order kinetic reaction was selected because one of this paper’s oblectives was to apply Lyapunov functionals to stability analysis of distributed parameter reactors (technique used in electrical engineering systems’ stability analysis. The stability analysis revealed asymptotically stable tempe- rature and concentration profiles for isothermal PFTR, non-isothermal PFTR with kinetic constant independent of temperature and adiabatic non-isothermal PFTR. Analysis revealed an asymptotically stability region for the heat exchange reactor and an uncertain region where it may have oscillations.
New explicit global asymptotic stability criteria for higher order difference equations
El-Morshedy, Hassan A.
2007-12-01
New explicit sufficient conditions for the asymptotic stability of the zero solution of higher order difference equations are obtained. These criteria can be applied to autonomous and nonautonomous equations. The celebrated Clark asymptotic stability criterion is improved. Also, applications to models from mathematical biology and macroeconomics are given.
STABILITY OF SOLUTIONS TO CERTAIN FOURTH-ORDER DELAY DIFFERENTIAL EQUATIONS
无
2010-01-01
By the Lyapunov functional approach, some better results on the asymptotic stabiBy the Lyapunov functional approach, some better results on the asymptotic stability and global asymptotic stability of zero solution to a certain fourth-order non-linear differential equation with delay are obtained.
De Basabe, Jonás D.
2010-04-01
We investigate the stability of some high-order finite element methods, namely the spectral element method and the interior-penalty discontinuous Galerkin method (IP-DGM), for acoustic or elastic wave propagation that have become increasingly popular in the recent past. We consider the Lax-Wendroff method (LWM) for time stepping and show that it allows for a larger time step than the classical leap-frog finite difference method, with higher-order accuracy. In particular the fourth-order LWM allows for a time step 73 per cent larger than that of the leap-frog method; the computational cost is approximately double per time step, but the larger time step partially compensates for this additional cost. Necessary, but not sufficient, stability conditions are given for the mentioned methods for orders up to 10 in space and time. The stability conditions for IP-DGM are approximately 20 and 60 per cent more restrictive than those for SEM in the acoustic and elastic cases, respectively. © 2010 The Authors Journal compilation © 2010 RAS.
ON THE BOUNDEDNESS AND THE STABILITY OF SOLUTION TO THIRD ORDER NON-LINEAR DIFFERENTIAL EQUATIONS
无
2008-01-01
In this paper we investigate the global asymptotic stability,boundedness as well as the ultimate boundedness of solutions to a general third order nonlinear differential equation,using complete Lyapunov function.
Stability and synchronization of memristor-based fractional-order delayed neural networks.
Chen, Liping; Wu, Ranchao; Cao, Jinde; Liu, Jia-Bao
2015-11-01
Global asymptotic stability and synchronization of a class of fractional-order memristor-based delayed neural networks are investigated. For such problems in integer-order systems, Lyapunov-Krasovskii functional is usually constructed, whereas similar method has not been well developed for fractional-order nonlinear delayed systems. By employing a comparison theorem for a class of fractional-order linear systems with time delay, sufficient condition for global asymptotic stability of fractional memristor-based delayed neural networks is derived. Then, based on linear error feedback control, the synchronization criterion for such neural networks is also presented. Numerical simulations are given to demonstrate the effectiveness of the theoretical results.
The need for higher-order averaging in the stability analysis of hovering, flapping-wing flight.
Taha, Haithem E; Tahmasian, Sevak; Woolsey, Craig A; Nayfeh, Ali H; Hajj, Muhammad R
2015-01-05
Because of the relatively high flapping frequency associated with hovering insects and flapping wing micro-air vehicles (FWMAVs), dynamic stability analysis typically involves direct averaging of the time-periodic dynamics over a flapping cycle. However, direct application of the averaging theorem may lead to false conclusions about the dynamics and stability of hovering insects and FWMAVs. Higher-order averaging techniques may be needed to understand the dynamics of flapping wing flight and to analyze its stability. We use second-order averaging to analyze the hovering dynamics of five insects in response to high-amplitude, high-frequency, periodic wing motion. We discuss the applicability of direct averaging versus second-order averaging for these insects.
Robust stabilizing first-order controllers for a class of time delay systems.
Saadaoui, Karim; Testouri, Sana; Benrejeb, Mohamed
2010-07-01
In this paper, stabilizing regions of a first-order controller for an all poles system with time delay are computed via parametric methods. First, the admissible ranges of one of the controller's parameters are obtained. Then, for a fixed value of this parameter, stabilizing regions in the remaining two parameters are determined using the D-decomposition method. Phase and gain margin specifications are then included in the design. Finally, robust stabilizing first-order controllers are determined for uncertain plants with an interval type uncertainty in the coefficients. Examples are given to illustrate the effectiveness of the proposed method.
Stability and Performance of First-Order Linear Time-Delay Feedback Systems: An Eigenvalue Approach
Shu-An He
2011-01-01
Full Text Available Linear time-delay systems with transcendental characteristic equations have infinitely many eigenvalues which are generally hard to compute completely. However, the spectrum of first-order linear time-delay systems can be analyzed with the Lambert function. This paper studies the stability and state feedback stabilization of first-order linear time-delay system in detail via the Lambert function. The main issues concerned are the rightmost eigenvalue locations, stability robustness with respect to delay time, and the response performance of the closed-loop system. Examples and simulations are presented to illustrate the analysis results.
Meng-Meng Jiang
2016-01-01
Full Text Available Under the weaker assumption on nonlinear functions, the adaptive finite-time stabilization of more general high-order nonlinear systems with dynamic and parametric uncertainties is solved in this paper. To solve this problem, finite-time input-to-state stability (FTISS is used to characterize the unmeasured dynamic uncertainty. By skillfully combining Lyapunov function, sign function, backstepping, and finite-time input-to-state stability approaches, an adaptive state feedback controller is designed to guarantee high-order nonlinear systems are globally finite-time stable.
Weak Second Order Explicit Stabilized Methods for Stiff Stochastic Differential Equations
Abdulle, Assyr
2013-01-01
We introduce a new family of explicit integrators for stiff Itô stochastic differential equations (SDEs) of weak order two. These numerical methods belong to the class of one-step stabilized methods with extended stability domains and do not suffer from the step size reduction faced by standard explicit methods. The family is based on the standard second order orthogonal Runge-Kutta-Chebyshev (ROCK2) methods for deterministic problems. The convergence, meansquare, and asymptotic stability properties of the methods are analyzed. Numerical experiments, including applications to nonlinear SDEs and parabolic stochastic partial differential equations are presented and confirm the theoretical results. © 2013 Society for Industrial and Applied Mathematics.
Global Mittag-Leffler Stabilization of Fractional-Order Memristive Neural Networks.
Wu, Ailong; Zeng, Zhigang
2015-12-22
According to conventional memristive neural network theories, neurodynamic properties are powerful tools for solving many problems in the areas of brain-like associative learning, dynamic information storage or retrieval, etc. However, as have often been noted in most fractional-order systems, system analysis approaches for integral-order systems could not be directly extended and applied to deal with fractional-order systems, and consequently, it raises difficult issues in analyzing and controlling the fractional-order memristive neural networks. By using the set-valued maps and fractional-order differential inclusions, then aided by a newly proposed fractional derivative inequality, this paper investigates the global Mittag--Leffler stabilization for a class of fractional-order memristive neural networks. Two types of control rules (i.e., state feedback stabilizing control and output feedback stabilizing control) are designed for the stabilization of fractional-order memristive neural networks, while a list of stabilization criteria is established. Finally, two numerical examples are given to show the effectiveness and characteristics of the obtained theoretical results.
Age-related differences in walking stability.
Menz, Hylton B; Lord, Stephen R; Fitzpatrick, Richard C
2003-03-01
a large proportion of falls in older people occur when walking; however the mechanisms underlying impaired balance during gait are poorly understood. to evaluate acceleration patterns at the head and pelvis in young and older subjects when walking on a level and an irregular walking surface, in order to develop an understanding of how ageing affects postural responses to challenging walking conditions. temporo-spatial gait parameters and variables derived from acceleration signals were recorded in 30 young people aged 22-39 years (mean 29.0, SD 4.3), and 30 older people with a low risk of falling aged 75-85 years (mean 79.0, SD 3.0) while walking on a level and an irregular walking surface. Subjects also underwent tests of vision, sensation, strength, reaction time and balance. older subjects exhibited a more conservative gait pattern, characterised by reduced velocity, shorter step length and increased step timing variability. These differences were particularly pronounced when walking on the irregular surface. The magnitude of accelerations at the head and pelvis were generally smaller in older subjects; however the smoothness of the acceleration signals did not differ between the two groups. Older subjects performed worse on tests of vision, peripheral sensation, strength, reaction time and balance. the adoption of a more conservative basic gait pattern by older people with a low risk of falling reduces the magnitude of accelerations experienced by the head and pelvis when walking, which is likely to be a compensatory strategy to maintain balance in the presence of age-related deficits in physiological function, particularly reduced lower limb strength.
Age-related differences in walking stability
Menz, Hylton B; Lord, Stephen R; Fitzpatrick, Richard C
2003-01-01
.... to evaluate acceleration patterns at the head and pelvis in young and older subjects when walking on a level and an irregular walking surface, in order to develop an understanding of how ageing...
Research on the stability, controllability and observability for fractional order LTI systems
WANG Zhen-bin; CAO Guang-yi; ZHU Xin-jian
2006-01-01
The state space representations of fractional order linear time-invariant (LTI ) systems are introduced, and their solution formulas are deduced by means of Laplace transform. The stability condition of fractional order LTI systems is given, and its proof is deduced by means of using linear non-singularity transform and the derivative property of Mittag-Leffler function. The controllability condition of fractional order LTI systems is given, and its proof is deduced by means of using its characteristic polynomial and the Cayley-Hamilton theorem. The observability condition of fractional order LTI systems is given, and its proof is deduced by means of their solution formulas. Finally an example is given to prove the correctness of the stability, controllability, and observability conditions mentioned above. s are deduced by means of Laplace transform. Their stability, controllability and observability conditions are given as well as their proofs.
A reduced-order method for estimating the stability region of power systems with saturated controls
GAN; DeQiang; XIN; HuanHai; QIU; JiaJu; HAN; ZhenXiang
2007-01-01
In a modern power system, there is often large difference in the decay speeds of transients. This could lead to numerical problems such as heavy simulation burden and singularity when the traditional methods are used to estimate the stability region of such a dynamic system with saturation nonlinearities. To overcome these problems, a reduced-order method, based on the singular perturbation theory, is suggested to estimate the stability region of a singular system with saturation nonlinearities. In the reduced-order method, a low-order linear dynamic system with saturation nonlinearities is constructed to estimate the stability region of the primary high-order system so that the singularity is eliminated and the estimation process is simplified. In addition, the analytical foundation of the reduction method is proven and the method is validated using a test power system with 3 buses and 5 machines.
Relating weak layer and slab properties to snow slope stability
J. Schweizer
2014-07-01
Full Text Available Snow slope stability evaluation requires considering weak layer as well as slab properties – and in particular their interaction. We developed a stability index from snow micro-penetrometer measurements and compared it to 129 concurrent point observations with the compression test (CT. The index considers the SMP-derived micro-structural strength and the additional load which depends on the hardness of the surface layers. The new quantitative measure of stability discriminated well between point observations rated as either "poor" or "fair" (CT < 19 and those rated as "good" (CT ≥ 19. However, discrimination power within the intermediate range was low. We then applied the index to gridded snow micro-penetrometer measurements from 11 snow slopes to explore the spatial structure and possibly relate it to slope stability. Stability distributions on the 11 slopes reflected various possible strength and load (stress distributions that naturally can occur. Their relation to slope stability was poor possibly because the index does not consider crack propagation. Hence, the relation between spatial patterns of point stability and slope stability remains elusive. Whereas this is the first attempt of a truly quantitative measure of stability, future developments should consider a better reference of stability and incorporate a measure of crack propagation.
Dynesys dynamic stabilization-related facet arthrodesis.
Fay, Li-Yu; Chang, Peng-Yuan; Wu, Jau-Ching; Huang, Wen-Cheng; Wang, Chun-Hao; Tsai, Tzu-Yun; Tu, Tsung-Hsi; Chang, Hsuan-Kan; Wu, Ching-Lan; Cheng, Henrich
2016-01-01
OBJECTIVE Dynamic stabilization devices are designed to stabilize the spine while preserving some motion. However, there have been reports demonstrating limited motion at the instrumented level of the lumbar spine after Dynesys dynamic stabilization (DDS). The causes of this limited motion and its actual effects on outcomes after DDS remain elusive. In this study, the authors investigate the incidence of unintended facet arthrodesis after DDS and clinical outcomes. METHODS This retrospective study included 80 consecutive patients with 1- or 2-level lumbar spinal stenosis who underwent laminectomy and DDS. All medical records, radiological data, and clinical evaluations were analyzed. Imaging studies included pre- and postoperative radiographs, MR images, and CT scans. Clinical outcomes were measured by a visual analog scale (VAS) for back and leg pain, the Oswestry Disability Index (ODI), and Japanese Orthopaedic Association (JOA) scores. Furthermore, all patients had undergone postoperative CT for the detection of unintended arthrodesis of the facets at the indexed level, and range of motion was measured on standing dynamic radiographs. RESULTS A total of 70 patients (87.5%) with a mean age of 64.0 years completed the minimum 24-month postoperative follow-up (mean duration 29.9 months). Unintended facet arthrodesis at the DDS instrumented level was demonstrated by CT in 38 (54.3%) of the 70 patients. The mean age of patients who had facet arthrodesis was 9.8 years greater than that of the patients who did not (68.3 vs 58.5 years, p = 0.009). There were no significant differences in clinical outcomes, including VAS back and leg pain, ODI, and JOA scores between patients with and without the unintended facet arthrodesis. Furthermore, those patients older than 60 years were more likely to have unintended facet arthrodesis (OR 12.42) and immobile spinal segments (OR 2.96) after DDS. Regardless of whether unintended facet arthrodesis was present or not, clinical
Wu, Ailong; Zeng, Zhigang
2016-02-01
We show that the ω-periodic fractional-order fuzzy neural networks cannot generate non-constant ω-periodic signals. In addition, several sufficient conditions are obtained to ascertain the boundedness and global Mittag-Leffler stability of fractional-order fuzzy neural networks. Furthermore, S-asymptotical ω-periodicity and global asymptotical ω-periodicity of fractional-order fuzzy neural networks is also characterized. The obtained criteria improve and extend the existing related results. To illustrate and compare the theoretical criteria, some numerical examples with simulation results are discussed in detail.
Stability-Controllable Second-Order Difference Scheme for Convection Term
无
1998-01-01
A new finite difference scheme-SCSD scheme has been propsed based on CD( Central Difference) scheme and SUD(Second-order Upwind Difference)scheme.Its basic feature is controllable convective stability and always second-order accuracy(Stability-Controllable Second-order Difference),It has been proven that this Scheme is convective-Stable if the grid Peclet number|PΔ|≤2/β（0≤β≤1).The advantage of this new scheme has been discussed based on the modified wavenumber analysis by using Fourier transform.This scheme has been applied to the 2-D incompressible convective-diffusive equation and 2-D compressible Euler equation,and corresponding finite difference equations have been derived.Numerical examples of 1-D Burgers equation and 2-D transport equation have been presented to show its good accuracy and controllable convective stability.
Rakkiyappan, R; Velmurugan, G; Cao, Jinde
2015-04-01
In this paper, the problem of the existence, uniqueness and uniform stability of memristor-based fractional-order neural networks (MFNNs) with two different types of memductance functions is extensively investigated. Moreover, we formulate the complex-valued memristor-based fractional-order neural networks (CVMFNNs) with two different types of memductance functions and analyze the existence, uniqueness and uniform stability of such networks. By using Banach contraction principle and analysis technique, some sufficient conditions are obtained to ensure the existence, uniqueness and uniform stability of the considered MFNNs and CVMFNNs with two different types of memductance functions. The analysis results establish from the theory of fractional-order differential equations with discontinuous right-hand sides. Finally, four numerical examples are presented to show the effectiveness of our theoretical results.
Solution of Second Order Supersymmetrical Intertwining Relations in Minkowski Plane
Ioffe, M V; Nishnianidze, D N
2016-01-01
Supersymmetrical (SUSY) intertwining relations are generalized to the case of quantum Hamiltonians in Minkowski space. For intertwining operators (supercharges) of second order in derivatives the intertwined Hamiltonians correspond to completely integrable systems with the symmetry operators of fourth order in momenta. In terms of components, the itertwining relations correspond to the system of nonlinear differential equations which are solvable with the simplest - constant - ansatzes for the "metric" matrix in second order part of the supercharges. The corresponding potentials are built explicitly both for diagonalizable and nondiagonalizable form of "metric" matrices, and their properties are discussed.
Solution of second order supersymmetrical intertwining relations in Minkowski plane
Ioffe, M. V.; Kolevatova, E. V.; Nishnianidze, D. N.
2016-08-01
Supersymmetrical (SUSY) intertwining relations are generalized to the case of quantum Hamiltonians in Minkowski space. For intertwining operators (supercharges) of second order in derivatives, the intertwined Hamiltonians correspond to completely integrable systems with the symmetry operators of fourth order in momenta. In terms of components, the intertwining relations correspond to the system of nonlinear differential equations which are solvable with the simplest—constant—ansatzes for the "metric" matrix in second order part of the supercharges. The corresponding potentials are built explicitly both for diagonalizable and nondiagonalizable form of "metric" matrices, and their properties are discussed.
Stability Analysis of a Class of Fractional-order Neural Networks
Tao Zou
2013-09-01
Full Text Available In this paper, the problems of the existence and uniqueness of solutions and stability for a class of fractional-order neural networks are studied by using Banach fixed point principle and analysis technique, respectively. A sufficient condition is given to ensure the existence and uniqueness of solutions and uniform stability of solutions for fractional-order neural networks with variable coefficients and multiple time delays. The obtained results improve and extend some previous works to some extent, and they are easy to check in practice. An illustrative example is presented to show the validity and application of the proposed results.
Matrix properties relating to stability analysis
Di Caprio, U. [ENEL s.p.a., Cologno Monzese (Italy)
2001-03-01
With reference to a multimachine power system are presented properties and conditions to be satisfied by matrices M, K, D (inertia coefficients, synchronizing coefficients and damping coefficients) in order that the system can be stable. The analysis is carried out with the assumption that the transfer-conductances are negligible while the damping effects (of the field and damper circuits) are taken into account. The formulation is general, i.e. it can be applied to any system with n degrees of freedom, subjected to conservative positional forces and to dissipative forces linearly dependent upon the speed. (author)
Review, Design, Optimization and Stability Analysis of Fractional-Order PID Controller
Ammar SOUKKOU
2016-07-01
Full Text Available This paper will establish the importance and significance of studying the fractional-order control of nonlinear dynamical systems. The foundation and the sources related to this research scope is going to be set. Then, the paper incorporates a brief overview on how this study is performed and present the organization of this study. The present work investigates the effectiveness of the physical-fractional and biological-genetic operators to develop an Optimal Form of Fractional-order PID Controller (O2Fo-PIDC. The newly developed Fo-PIDC with optimal structure and parameters can, also, improve the performances required in the modeling and control of modern manufacturing-industrial process (MIP. The synthesis methodology of the proposed O2Fo-PIDC can be viewed as a multi-level design approach. The hierarchical Multiobjective genetic algorithm (MGA, adopted in this work, can be visualized as a combination of structural and parametric genes of a controller orchestrated in a hierarchical fashion. Then, it is applied to select an optimal structure and knowledge base of the developed fractional controller to satisfy the various design specification contradictories (simplicity, accuracy, stability and robustness.
Relative effects at work : Bayes factors for order hypotheses
Braeken, J.; Mulder, J.; Wood, S.
2015-01-01
Assessing the relative importance of predictors has been of historical importance in a variety of disciplines including management, medicine, economics, and psychology. When approaching hypotheses on the relative ordering of the magnitude of predicted effects (e.g., the effects of discrimination fro
On the Linear Stability of the Fifth-Order WENO Discretization
Motamed, Mohammad
2010-10-03
We study the linear stability of the fifth-order Weighted Essentially Non-Oscillatory spatial discretization (WENO5) combined with explicit time stepping applied to the one-dimensional advection equation. We show that it is not necessary for the stability domain of the time integrator to include a part of the imaginary axis. In particular, we show that the combination of WENO5 with either the forward Euler method or a two-stage, second-order Runge-Kutta method is linearly stable provided very small time step-sizes are taken. We also consider fifth-order multistep time discretizations whose stability domains do not include the imaginary axis. These are found to be linearly stable with moderate time steps when combined with WENO5. In particular, the fifth-order extrapolated BDF scheme gave superior results in practice to high-order Runge-Kutta methods whose stability domain includes the imaginary axis. Numerical tests are presented which confirm the analysis. © Springer Science+Business Media, LLC 2010.
Relativity stability of quantum gas in a weak magnetic field
Men Fu-Dian; Liu Hui; Fan Zhao-Lan; Zhu Hou-Yu
2009-01-01
Based on the analytical expression of relativistic free energy for a weakly interacting Fermi gas in a weak magnetic field,by using the method of quantum statistics,the stability conditions of the system at both high and low temperatures axe given,and the effects of magnetic field and interpaxticle interactions on the stability of the system are analysed. It is shown that at high temperatures,the stability conditions of the system are completely the same,no matter whether it is the ultrarelativistic case or nonrelativistic case. At extremely low temperatures,the mechanical stability conditions of the system show a similar rule through a comparison between the ultrarelativistic case and nonrelativistic case. At the same time,thermal stability of a relativistic Bose gas in a weak magnetic field is discussed,and the influence of the effect of relativity on the thermal stability of the system is investigated.
Investigation of the Stability of POD-Galerkin Techniques for Reduced Order Model Development
2016-01-09
CFD solutions comparison of Case A at x/L = 0.5 for cases in Table 4. 12 The remaining three cases with multiple frequencies in the forcing function...Techniques for Reduced Order Model Development 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Huang, C...mitigate the stability issues encountered in developing a reduced order model (ROM) for combustion response to specified excitations using the Euler
Second-order stabilized explicit Runge-Kutta methods for stiff problems
Martín-Vaquero, J.; Janssen, B.
2009-10-01
Stabilized Runge-Kutta methods (they have also been called Chebyshev-Runge-Kutta methods) are explicit methods with extended stability domains, usually along the negative real axis. They are easy to use (they do not require algebra routines) and are especially suited for MOL discretizations of two- and three-dimensional parabolic partial differential equations. Previous codes based on stabilized Runge-Kutta algorithms were tested with mildly stiff problems. In this paper we show that they have some difficulties to solve efficiently problems where the eigenvalues are very large in absolute value (over 10 5). We also develop a new procedure to build this kind of algorithms and we derive second-order methods with up to 320 stages and good stability properties. These methods are efficient numerical integrators of very large stiff ordinary differential equations. Numerical experiments support the effectiveness of the new algorithms compared to well-known methods as RKC, ROCK2, DUMKA3 and ROCK4.
Stabilization of solutions to higher-order nonlinear Schrodinger equation with localized damping
Eleni Bisognin
2007-01-01
Full Text Available We study the stabilization of solutions to higher-order nonlinear Schrodinger equations in a bounded interval under the effect of a localized damping mechanism. We use multiplier techniques to obtain exponential decay in time of the solutions of the linear and nonlinear equations.
Atomically Thin Ordered Alloys of Transition Metal Dichalcogenides: Stability and Band Structures
Pandey, Mohnish; Jacobsen, Karsten Wedel; Thygesen, Kristian Sommer
2016-01-01
We explore the possibility of modulating the electronic band edges of the transition metal dichalcogenides (TMD) via alloying of different semiconductors within the same group (intra-group alloying). The stability of the ordered alloys is assessed from the calculated mixing enthalpy which is found...
Husbands' Marriage Order and the Stability of First and Second Marriages of White and Black Women.
Aguirre, B. E.; Parr, W. C.
1982-01-01
Evaluated the effect of previous marital history, particularly the husband's marriage order, on the stability of first and second marriages of White and Black women. The most important predictor of the instability of first marriages of women are the previous divorces of husbands. (Author)
Stabilization for a class of second-order switched systems with saturation constrains
SONG Yang; GU Yu-qi; FEI Min-rui
2009-01-01
This paper proposes a global stabilization method for a class of planar switched systems with input saturation constrains by using a state feedback and switching strategy.This method is proved to be effective by analyzing the characteristics of the trajectory of second-order linear systems with input saturation.
On Existence and Stability of Solutions for Higher Order Semilinear Dirichlet Problems
Marek Galewski
2008-11-01
We provide existence and stability results for semilinear Dirichlet problems with nonlinearity satisfying general growth conditions. We consider the case when both the coefficients of the differential operator and the nonlinear term depend on the numerical parameter. We show applications for the fourth order semilinear Dirichlet problem.
Toddlers infer higher-order relational principles in causal learning.
Walker, Caren M; Gopnik, Alison
2014-01-01
Children make inductive inferences about the causal properties of individual objects from a very young age. When can they infer higher-order relational properties? In three experiments, we examined 18- to 30-month-olds' relational inferences in a causal task. Results suggest that at this age, children are able to infer a higher-order relational causal principle from just a few observations and use this inference to guide their own subsequent actions and bring about a novel causal outcome. Moreover, the children passed a revised version of the relational match-to-sample task that has proven very difficult for nonhuman primates. The findings are considered in light of their implications for understanding the nature of relational and causal reasoning, and their evolutionary origins.
Second-order relative exponent of isotropic turbulence
无
2011-01-01
Theoretical results on the scaling properties of turbulent velocity fields are reported in this letter.Based on the Kolmogorov equation and typical models of the second-order statistical moments (energy spectrum and the second-order structure function),we have studied the relative scaling using the ESS method.It is found that the relative EES scaling exponent S_2 is greater than the real or theoretical inertial range scaling exponentξ_2,which is attributed to an evident bump in the ESS range.
Stability change of Fourth-Order Resonance with application to Multi-Turn Extraction Schemes
Giovannozzi, M; Turchetti, G
2008-01-01
Recently, a novel multi-turn extraction scheme was proposed, based on particle trapping inside stable resonances. Numerical simulations and experimental tests conirmed the feasibility of such a scheme for low order resonances. While the 3rd order resonance is generically unstable and those higher than 4th order are generically stable, the 4th order resonance can be either stable or unstable depending on the details of the system under consideration. By means of the normal form approach a general formula to control the stability of the 4th order resonance is derived. Numerical simulations confirm the analytical results and show that by crossing the unstable 4th order resonance the region around the centre of phase space is depleted and particles are trapped only in the four stable islands. This indicates that a four-turn extraction could be envisaged based on this technique.
Quantification of Partially Ordered Sets with Application to Special Relativity
Bahreyni, Newshaw; Knuth, Kevin H.
2011-03-01
A partially ordered set is a set of elements ordered by a binary ordering relation. We have shown that a subset of a partially ordered set can be quantified by projecting elements onto a pair of chains where the elements of each chain are quantified by real numbers. This results in a quantification based on pairs of real numbers (pair). Intervals, defined by pairs of elements, can be quantified similarly. A pair can be decomposed into a sum of a symmetric pair and an antisymmetric pair and mapped to a unique scalar which results in the Minkowskian form. Changing the basis of quantification from one pair of chains to another, under special conditions, leads to the generalized Lorentz transformation for pairs. We apply these results to a causally-ordered set of events by identifying a chain of events with an observer equipped with a clock in an inertial frame. We obtain the Minkowski metric of flat space-time as well as Lorentz transformations, which results in there being a maximum invariant speed. We find that the mathematics of special relativity arises from quantifying causal relationships among events, and requires neither the principle of relativity nor the fact that the speed of light is constant.
Threshold singularities, dispersion relations and fixed-order perturbative calculations
Beneke, Martin
2016-01-01
We show how to correctly treat threshold singularities in fixed-order perturbative calculations of the electron anomalous magnetic moment and hadronic pair production processes such as top pair production. With respect to the former, we demonstrate the equivalence of the "non-perturbative", resummed treatment of the vacuum polarization contribution, whose spectral function exhibits bound state poles, with the fixed-order calculation by identifying a threshold localized term in the four-loop spectral function. In general, we find that a modification of the dispersion relation by threshold subtractions is required to make fixed-order calculations well-defined and provide the subtraction term. We then solve the apparent problem of a divergent convolution of the partonic cross section with the parton luminosity in the computation of the top pair production cross section starting from the fourth-order correction. We find that when the computation is performed in the usual way as an integral of real and virtual cor...
Raghunathan, Krishnan; Wong, Tiffany H; Chinnapen, Daniel J; Lencer, Wayne I; Jobling, Michael G; Kenworthy, Anne K
2016-12-20
Current models of lipid rafts propose that lipid domains exist as nanoscale compositional fluctuations and these fluctuations can potentially be stabilized into larger domains, consequently better compartmentalizing cellular functions. However, the mechanisms governing stabilized raft assembly and function remain unclear. Here, we test the role of glycolipid crosslinking as a raft targeting and ordering mechanism using the well-studied raft marker cholera toxin B pentamer (CTxB) that binds up to five GM1 glycosphingolipids to enter host cells. We show that when applied to cell-derived giant plasma membrane vesicles, a variant of CTxB containing only a single functional GM1 binding site exhibits significantly reduced partitioning to the ordered phase compared to wild-type CTxB with five binding sites. Moreover, monovalent CTxB does not stabilize membrane domains, unlike wild-type CTxB. These results support the long-held hypothesis that CTxB stabilizes raft domains via a lipid crosslinking mechanism and establish a role for crosslinking in the partitioning of CTxB to ordered domains.
33 CFR 335.6 - Related laws and Executive Orders.
2010-07-01
... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Related laws and Executive Orders. 335.6 Section 335.6 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE OPERATION AND MAINTENANCE OF ARMY CORPS OF ENGINEERS CIVIL WORKS PROJECTS INVOLVING THE...
LIU Yungang; ZHANG Jifeng
2004-01-01
A minimal-order observer and output-feedback stabilization control are given for single-input multi-output stochastic nonlinear systems with unobservable states, unmodelled dynamics and stochastic disturbances. Based on the observer designed, the estimates of all observable states of the system are given, and the convergence of the estimation errors are analyzed. In addition, by using the integrator backstepping approach,an output-feedback stabilization control is constructively designed, and sufficient conditions are obtained under which the closed-loop system is asymptotically stable in the large or bounded in probability, respectively.
Energy method for Stability of 1st Order CE with Variable Coefficients
LIU Ming
2011-01-01
It is well known that the Convection--diffusion e- quations arise in the fields of fluid mechanics and has been con- sidered extensively. The solving for these initial boundary value problems includes upwind difference scheme, Las- Friedrichs and Lax-- Wendroff difference schemes etc.. Methods such as Matrix method, the Hirt Heuristic Method and Fourier Method can be used to research the stability of the difference schemes. In the paper, using the 1st order convection equation（CE） with var- iable- coefficients as an example, the author gets the corre- sponding Lax--Wendroff difference scheme first, then Energy Method has been used to analyze the stability of the scheme.
Global Stabilization of High-Order Time-Delay Nonlinear Systems under a Weaker Condition
Nengwei Zhang
2014-01-01
Full Text Available Under the weaker condition on the system growth, this paper further investigates the problem of global stabilization by state feedback for a class of high-order nonlinear systems with time-varying delays. By skillfully using the homogeneous domination approach, a continuous state feedback controller is successfully designed, which preserves the equilibrium at the origin and guarantees the global asymptotic stability of the resulting closed-loop system. A simulation example is given to demonstrate the effectiveness of the proposed design procedure.
Wallach, Arian D; Ritchie, Euan G; Read, John; O'Neill, Adam J
2009-09-02
Population control of socially complex species may have profound ecological implications that remain largely invisible if only their abundance is considered. Here we discuss the effects of control on a socially complex top-order predator, the dingo (Canis lupus dingo). Since European occupation of Australia, dingoes have been controlled over much of the continent. Our aim was to investigate the effects of control on their abundance and social stability. We hypothesized that dingo abundance and social stability are not linearly related, and proposed a theoretical model in which dingo populations may fluctuate between three main states: (A) below carrying capacity and socially fractured, (B) above carrying capacity and socially fractured, or (C) at carrying capacity and socially stable. We predicted that lethal control would drive dingoes into the unstable states A or B, and that relaxation of control would allow recovery towards C. We tested our predictions by surveying relative abundance (track density) and indicators of social stability (scent-marking and howling) at seven sites in the arid zone subject to differing degrees of control. We also monitored changes in dingo abundance and social stability following relaxation and intensification of control. Sites where dingoes had been controlled within the previous two years were characterized by low scent-marking activity, but abundance was similar at sites with and without control. Signs of social stability steadily increased the longer an area was allowed to recover from control, but change in abundance did not follow a consistent path. Comparison of abundance and stability among all sites and years demonstrated that control severely fractures social groups, but that the effect of control on abundance was neither consistent nor predictable. Management decisions involving large social predators must therefore consider social stability to ensure their conservation and ecological functioning.
Fuhrmann, David R.; Bingham, Harry B.; Madsen, Per A.;
2004-01-01
This paper considers a method of lines stability analysis for finite difference discretizations of a recently published Boussinesq method for the study of highly nonlinear and extremely dispersive water waves. The analysis demonstrates the near-equivalence of classical linear Fourier (von Neumann......) techniques with matrix-based methods for formulations in both one and two horizontal dimensions. The matrix-based method is also extended to show the local de-stabilizing effects of the nonlinear terms, as well as the stabilizing effects of numerical dissipation. A comparison of the relative stability...... moderately non-normal, suggesting that the eigenvalues are likely suitable for analysis purposes. Numerical experiments demonstrate excellent agreement with the linear analysis, and good qualitative agreement with the local nonlinear analysis. The various methods of analysis combine to provide significant...
Birth order and selected work-related personality variables.
Phillips, A S; Bedeian, A G; Mossholder, K W; Touliatos, J
1988-12-01
A possible link between birth order and various individual characteristics (e. g., intelligence, potential eminence, need for achievement, sociability) has been suggested by personality theorists such as Adler for over a century. The present study examines whether birth order is associated with selected personality variables that may be related to various work outcomes. 3 of 7 hypotheses were supported and the effect sizes for these were small. Firstborns scored significantly higher than later borns on measures of dominance, good impression, and achievement via conformity. No differences between firstborns and later borns were found in managerial potential, work orientation, achievement via independence, and sociability. The study's sample consisted of 835 public, government, and industrial accountants responding to a national US survey of accounting professionals. The nature of the sample may have been partially responsible for the results obtained. Its homogeneity may have caused any birth order effects to wash out. It can be argued that successful membership in the accountancy profession requires internalization of a set of prescribed rules and standards. It may be that accountants as a group are locked in to a behavioral framework. Any differentiation would result from spurious interpersonal differences, not from predictable birth-order related characteristics. A final interpretation is that birth order effects are nonexistent or statistical artifacts. Given the present data and particularistic sample, however, the authors have insufficient information from which to draw such a conclusion.
Stabilization of generalized fractional order chaotic systems using state feedback control
Ahmad, Wajdi M. E-mail: wajdi@sharjah.ac.ae; El-Khazali, Reyad E-mail: khazali@ece.ac.ae; Al-Assaf, Yousef E-mail: yassaf@aus.ac.ae
2004-10-01
In this paper, we address the problem of chaos control of three types of fractional order systems using simple state feedback gains. Electronic chaotic oscillators, mechanical 'jerk' systems, and the Chen system are investigated when they assume generalized fractional orders. We design the static gains to place the eigenvalues of the system Jacobian matrices in a stable region whose boundaries are determined by the orders of the fractional derivatives. We numerically demonstrate the effectiveness of the controller in eliminating the chaotic behavior from the state trajectories, and driving the states to the nearest equilibrium point in the basin of attraction. For the recently introduced Chen system, in particular, we demonstrate that with a proper choice of model parameters, chaotic behavior is preserved when the system order becomes fractional. Both state and output feedback controllers are then designed to stabilize a generalized fractional order Chen system.
Jones, Andrew O F; Knauer, Philipp; Resel, Roland; Ringk, Andreas; Strohriegl, Peter; Werzer, Oliver; Sferrazza, Michele
2015-06-01
The thermal stability and molecular order in monolayers of two organic semiconductors, PBI-PA and PBI-alkyl, based on perylene derivatives with an identical molecular structure except for an anchor group for attachment to the substrate in PBI-PA, are reported. In situ X-ray reflectivity measurements are used to follow the stability of these monolayers in terms of order and thickness as temperature is increased. Films have thicknesses corresponding approximately to the length of one molecule; molecules stand upright on the substrate with a defined structure. PBI-PA monolayers have a high degree of order at room temperature and a stable film exists up to 250 °C, but decomposes rapidly above 300 °C. In contrast, stable physisorbed PBI-alkyl monolayers only exist up to 100 °C. Above the bulk melting point at 200 °C no more order exists. The results encourage using anchor groups in monolayers for various applications as it allows enhanced stability at the interface with the substrate.
Reduced-Order Kalman Filtering for Processing Relative Measurements
Bayard, David S.
2008-01-01
A study in Kalman-filter theory has led to a method of processing relative measurements to estimate the current state of a physical system, using less computation than has previously been thought necessary. As used here, relative measurements signifies measurements that yield information on the relationship between a later and an earlier state of the system. An important example of relative measurements arises in computer vision: Information on relative motion is extracted by comparing images taken at two different times. Relative measurements do not directly fit into standard Kalman filter theory, in which measurements are restricted to those indicative of only the current state of the system. One approach heretofore followed in utilizing relative measurements in Kalman filtering, denoted state augmentation, involves augmenting the state of the system at the earlier of two time instants and then propagating the state to the later time instant.While state augmentation is conceptually simple, it can also be computationally prohibitive because it doubles the number of states in the Kalman filter. When processing a relative measurement, if one were to follow the state-augmentation approach as practiced heretofore, one would find it necessary to propagate the full augmented state Kalman filter from the earlier time to the later time and then select out the reduced-order components. The main result of the study reported here is proof of a property called reduced-order equivalence (ROE). The main consequence of ROE is that it is not necessary to augment with the full state, but, rather, only the portion of the state that is explicitly used in the partial relative measurement. In other words, it suffices to select the reduced-order components first and then propagate the partial augmented state Kalman filter from the earlier time to the later time; the amount of computation needed to do this can be substantially less than that needed for propagating the full augmented
Stability and Relative Stability of Linear Systems with Many Constant Time Delays. Ph.D. Thesis
Barker, Larry Keith
1976-01-01
A method of determining the stability of linear systems with many constant time delays is developed. This technique, an extension of the tau-decomposition method, is used to examine not only the stability but also the relative stability of retarded systems with many delays and a class of neutral equations with one delay. Analytical equations are derived for partitioning the delay space of a retarded system with two time delays. The stability of the system in each of the regions defined by the partitioning curves in the parameter plane is determined using the extended tau-decomposition method. In addition, relative stability boundaries are defined using the extended tau-decompositon method in association with parameter plane techniques. Several applications of the extended tau-decomposition method are presented and compared with stability results obtained from other analyses. In all cases the results obtained using the method outlined herein coincide with and extend those of previous investigations. The extended tau-decomposition method applied to systems with time delays requires less computational effort and yields more complete stability analyses than previous techniques.
Relations Between Stabilities and Structures of Closo Borane Dianions
LI Ping
2006-01-01
An effective method to investigate the stabilities of a series of new closo-BnHn2-(n = 12, 14, 16, 18, 20, 22, 24, 30) was put forward with the aid of G96PW91/SHC calculations. Stabilities are related to the relative stabilized energies (RSE) and the 2e3c bound geometries of closo-BnHn2-. The structures in which a boron atom connects to four atoms up to seven are stable and appear in many borides because of the lower relative stabilized energy. In geometries, both triangular and quadrangular faces are in favor of forming the structures of closo-BnHn2-. The energies of optimized geometries support the existence of these new compounds. By employing both RSE and ▲E per boron atom in cage, the stabilities were studied to predict the probabilities of unknown clusters in existence. The electron-deficient clusters can be understood that the positive holes should be disperse to every triangular face and lead to share the holes, wherever there are not enough electrons to occupy them. The negative charges which anions carry distribute to 2e3c bonds to increase the stabilities.
The Physical Squeezed Limit: Consistency Relations at Order q^2
Creminelli, Paolo; Senatore, Leonardo; Simonović, Marko; Trevisan, Gabriele
2013-01-01
In single-field models of inflation the effect of a long mode with momentum q reduces to a diffeomorphism at zeroth and first order in q. This gives the well-known consistency relations for the n-point functions. At order q^2 the long mode has a physical effect on the short ones, since it induces curvature, and we expect that this effect is the same as being in a curved FRW universe. In this paper we verify this intuition in various examples of the three-point function, whose behaviour at order q^2 can be written in terms of the power spectrum in a curved universe. This gives a simple alternative understanding of the level of non-Gaussianity in single-field models. Non-Gaussianity is always parametrically enhanced when modes freeze at a physical scale k_{ph, f} shorter than H: f_{NL} \\sim (k_{ph, f}/H)^2.
The physical squeezed limit: consistency relations at order q2
Creminelli, Paolo; Perko, Ashley; Senatore, Leonardo; Simonović, Marko; Trevisan, Gabriele
2013-11-01
In single-field models of inflation the effect of a long mode with momentum q reduces to a diffeomorphism at zeroth and first order in q. This gives the well-known consistency relations for the n-point functions. At order q2 the long mode has a physical effect on the short ones, since it induces curvature, and we expect that this effect is the same as being in a curved FRW universe. In this paper we verify this intuition in various examples of the three-point function, whose behaviour at order q2 can be written in terms of the power spectrum in a curved universe. This gives a simple alternative understanding of the level of non-Gaussianity in single-field models. Non-Gaussianity is always parametrically enhanced when modes freeze at a physical scale kph, f shorter than H: fNL ~ (kph, f/H)2.
Analysis of electrostatic stability and ordering in quaternary perovskite solid solutions
Caetano, Clovis; Butler, Keith T.; Walsh, Aron
2016-04-01
There are three distinct classes of perovskite structured metal oxides, defined by the charge states of the cations: AIBVO3,AIIBIVO3 , and AIIIBIIIO3 . We investigated the stability of cubic quaternary solid solutions A B O3-A'B'O3 using a model of point-charge lattices. The mixing enthalpies were calculated and compared for the three possible types of combinations of the compounds, both for the random alloys and the ground-state-ordered configurations. The mixing enthalpy of the (I,V)O3-(III,III)O3 alloy is always larger than the other alloys. We found that, different from homovalent alloys, for these heterovalent alloys a lattice constant mismatch between the constituent compounds could contribute to stabilize the alloy. At low temperatures, the alloys present a tendency to spontaneous ordering, forming superlattices consisting of alternated layers of AB O 3 and A'B'O3 along the [110 ] direction.
Velmurugan, G; Rakkiyappan, R; Vembarasan, V; Cao, Jinde; Alsaedi, Ahmed
2017-02-01
As we know, the notion of dissipativity is an important dynamical property of neural networks. Thus, the analysis of dissipativity of neural networks with time delay is becoming more and more important in the research field. In this paper, the authors establish a class of fractional-order complex-valued neural networks (FCVNNs) with time delay, and intensively study the problem of dissipativity, as well as global asymptotic stability of the considered FCVNNs with time delay. Based on the fractional Halanay inequality and suitable Lyapunov functions, some new sufficient conditions are obtained that guarantee the dissipativity of FCVNNs with time delay. Moreover, some sufficient conditions are derived in order to ensure the global asymptotic stability of the addressed FCVNNs with time delay. Finally, two numerical simulations are posed to ensure that the attention of our main results are valuable.
Synthesis of Ordered Cubic Periodic Mesoporous Silica with High Hydrothermal Stability
LAI Xiao-yong; TU Jin-chun; WANG Hong; DU Jiang; YANG Mei; MAO Dan; XING Chao-jian; WANG Dan; LI Xiao-tian
2009-01-01
@@ 1 Introduction Since its first discovery in 1992~[1,2], ordered me-soporous silica material with large pore size, high surface area, and high pore volume has attracted great attention for the potentially wide application in catalysis, adsorption, separation, and ion exchange, etc. However, the poor hydrothermal stability of meso-porous silica has limited its wide application in industry~[3,4].
The relative worst order ratio applied to paging
Boyar, Joan; Favrholdt, Lene Monrad; Larsen, Kim Skak
2007-01-01
The relative worst order ratio, a new measure for the quality of on-line algorithms, was recently defined and applied to two bin packing problems. Here, we apply it to the paging problem and obtain the following results: We devise a new deterministic paging algorithm, Retrospective-LRU, and show...... that it performs better than LRU. This is supported by experimental results, but contrasts with the competitive ratio. All deterministic marking algorithms have the same competitive ratio, but here we find that LRU is better than FWF. According to the relative worst order ratio, no deterministic marking algorithm...... can be significantly better than LRU, but the randomized algorithm MARK is better than LRU. Finally, look-ahead is shown to be a significant advantage, in contrast to the competitive ratio, which does not reflect that look-ahead can be helpful....
Threshold singularities, dispersion relations and fixed-order perturbative calculations
Beneke, M.; Ruiz-Femenía, P. [Physik Department T31, Technische Universität München,James-Franck-Straße, D-85748 Garching (Germany)
2016-08-24
We show how to correctly treat threshold singularities in fixed-order perturbative calculations of the electron anomalous magnetic moment and hadronic pair production processes such as top pair production. With respect to the former, we demonstrate the equivalence of the “non-perturbative”, resummed treatment of the vacuum polarization contribution, whose spectral function exhibits bound state poles, with the fixed-order calculation by identifying a threshold localized term in the four-loop spectral function. In general, we find that a modification of the dispersion relation by threshold subtractions is required to make fixed-order calculations well-defined and provide the subtraction term. We then solve the apparent problem of a divergent convolution of the partonic cross section with the parton luminosity in the computation of the top pair production cross section starting from the fourth-order correction. We find that when the computation is performed in the usual way as an integral of real and virtual corrections over phase space at a given order in the expansion in the strong coupling, an additional contribution has to be added at N3LO.
Tahavori, Maryamsadat; Shaker, Hamid Reza
A method for model reduction of dynamical systems with the second order structure is proposed in this paper. The proposed technique preserves the second order structure of the system, and also preserves the stability of the original systems. The method uses the controllability and observability...... gramians within the time interval to build the appropriate Petrov-Galerkin projection for dynamical systems within the time interval of interest. The bound on approximation error is also derived. The numerical results are compared with the counterparts from other techniques. The results confirm...
Resonator stability and higher-order modes in free-electron laser oscillators
Pathak, Abhishek; Krishnagopal, Srinivas
2014-08-01
Three-dimensional simulation codes genesis and opc are used to investigate the dependence of the resonator stability of free-electron laser (FEL) oscillators on the stability parameter, laser wavelength, outcoupling hole size and mirror tilt. We find that to have stable lasing over a wide range of wavelengths, the FEL cavity configuration should be carefully chosen. Broadly, the concentric configuration gives near-Gaussian modes and the best performance. At intermediate configurations the dominant mode often switches to a higher-order mode, which kills lasing. For the same reason, the outcoupled power can also be less. We have constructed a simple analytic model to study resonator stability which gives results that are in excellent agreement with the simulations. This suggests that modes in FEL oscillators are determined more by the cavity configuration and radiation propagation than by the details of the FEL interaction. We find (as in experiments at the CLIO FEL) that tilting the mirror can, for some configurations, lead to more outcoupled power than a perfectly aligned mirror because the mode is now a more compact higher-order mode, which may have implications for the mode quality for user experiments. Finally, we show that the higher-order mode obtained is usually a single Gauss-Laguerre mode, and therefore it should be possible to filter out the mode using suitable intracavity elements, leading to better FEL performance.
Stability and ordering properties of fcc alloys based on Rh, Ir, Pd, and Pt
Turchi, P. E. A.; Drchal, V.; Kudrnovský, J.
2006-08-01
Stability properties and ordering trends for the six face-centered cubic binary combinations of the four transition metals Rh, Ir, Pd, and Pt are examined in the context of electronic structure calculations. The method is based on a Green’s function description of the electronic structure of random alloys. Configurational order is treated within the generalized perturbation method. On one hand, the three alloys Pd-Rh, Pd-Ir, and Pt-Ir that have been studied experimentally are confirmed to behave like phase-separating systems. On the other hand, the other three mixtures Pd-Pt, Rh-Ir, and Pt-Rh, for which phase-separating trends have been inferred from experiments, are found to display chemical order with ordering of the (1 0 0) and (11/20) family types and a mixture of both, respectively. The origin of these results is discussed in terms of electronic structure properties.
Hexagonal phase stabilization and magnetic orders of multiferroic L u1 -xS cxFe O3
Lin, L.; Zhang, H. M.; Liu, M. F.; Shen, Shoudong; Zhou, S.; Li, D.; Wang, X.; Yan, Z. B.; Zhang, Z. D.; Zhao, Jun; Dong, Shuai; Liu, J.-M.
2016-02-01
Hexagonal LuFe O3 has drawn a lot of research attention due to its contentious room-temperature multiferroicity. Due to the instability of hexagonal phase in the bulk form, most experimental studies focused on LuFe O3 thin films which can be stabilized by strain using proper substrates. Here we report on the hexagonal phase stabilization, magnetism, and magnetoelectric coupling of bulk LuFe O3 by partial Sc substitution of Lu. First, our first-principles calculations show that the hexagonal structure can be stabilized by partial Sc substitution, while the multiferroic properties, including the noncollinear magnetic order and geometric ferroelectricity, remain robustly unaffected. Therefore, L u1 -xS cxFe O3 can act as a platform to check the multiferroicity of LuFe O3 and related materials in the bulk form. Second, the magnetic characterizations on bulk L u1 -xS cxFe O3 demonstrate a magnetic anomaly (probable antiferromagnetic ordering) above room temperature, ˜425-445 K, followed by magnetic transitions in low temperatures (˜167-172 K). In addition, a magnetoelectric response is observed in the low-temperature region. Our study provides useful information on the multiferroic physics of hexagonal R Fe O3 and related systems.
Linear and nonlinear stability analysis in BWRs applying a reduced order model
Olvera G, O. A.; Espinosa P, G.; Prieto G, A., E-mail: omar_olverag@hotmail.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco No. 186, Col. Vicentina, 09340 Ciudad de Mexico (Mexico)
2016-09-15
Boiling Water Reactor (BWR) stability studies are generally conducted through nonlinear reduced order models (Rom) employing various techniques such as bifurcation analysis and time domain numerical integration. One of those models used for these studies is the March-Leuba Rom. Such model represents qualitatively the dynamic behavior of a BWR through a one-point reactor kinetics, a one node representation of the heat transfer process in fuel, and a two node representation of the channel Thermal hydraulics to account for the void reactivity feedback. Here, we study the effect of this higher order model on the overall stability of the BWR. The change in the stability boundaries is determined by evaluating the eigenvalues of the Jacobian matrix. The nonlinear model is also integrated numerically to show that in the nonlinear region, the system evolves to stable limit cycles when operating close to the stability boundary. We also applied a new technique based on the Empirical Mode Decomposition (Emd) to estimate a parameter linked with stability in a BWR. This instability parameter is not exactly the classical Decay Ratio (Dr), but it will be linked with it. The proposed method allows decomposing the analyzed signal in different levels or mono-component functions known as intrinsic mode functions (Imf). One or more of these different modes can be associated to the instability problem in BWRs. By tracking the instantaneous frequencies (calculated through Hilbert Huang Transform (HHT) and the autocorrelation function (Acf) of the Imf linked to instability. The estimation of the proposed parameter can be achieved. The current methodology was validated with simulated signals of the studied model. (Author)
Axiomatization of Special Relativity in First Order Logic
Luo, Yi-Chen; Chen, Lei; He, Wan-Ting; Ma, Yong-Ge; Zhang, Xin-Yu
2016-07-01
The axiomatization of physical theories is a fundamental issue of science. The first-order axiomatic system SpecRel for special relativity proposed recently by Andréka et al. is not enough to explain all the main results in the theory, including the twin paradox and energy-mass relation. In this paper, from a four-dimensional space-time perspective, we introduce the concepts of world-line, proper time and four-momentum to our axiomatic system SpecRel+. Then we introduce an axiom of mass (AxMass) and take four-momentum conservation as an axiom (AxCFM) in SpecRel+. It turns out that the twin paradox and energy-mass relation can be derived from SpecRel+ logically. Hence, as an extension of SpecRel, SpecRel+ is a suitable first-order axiomatic system to describe the kinematics and dynamics of special relativity. Supported by the National Science Foundation of China under Grant Nos. 11235003 and 11475023, National Social Sciences Foundation of China under Grant No. 14BZX078 and the Research Fund for the Doctoral Program of Higher Education of China, and the Undergraduate Training Program of Beijing
A Recurrence Relation Approach to Higher Order Quantum Superintegrability
Ernie G. Kalnins
2011-03-01
Full Text Available We develop our method to prove quantum superintegrability of an integrable 2D system, based on recurrence relations obeyed by the eigenfunctions of the system with respect to separable coordinates. We show that the method provides rigorous proofs of superintegrability and explicit constructions of higher order generators for the symmetry algebra. We apply the method to 5 families of systems, each depending on a parameter k, including most notably the caged anisotropic oscillator, the Tremblay, Turbiner and Winternitz system and a deformed Kepler-Coulomb system, and we give proofs of quantum superintegrability for all rational values of k, new for 4 of these systems. In addition, we show that the explicit information supplied by the special function recurrence relations allows us to prove, for the first time in 4 cases, that the symmetry algebra generated by our lowest order symmetries closes and to determine the associated structure equations of the algebras for each k. We have no proof that our generating symmetries are of lowest possible order, but we have no counterexamples, and we are confident we can can always find any missing generators from our raising and lowering operator recurrences. We also get for free, one variable models of the action of the symmetry algebra in terms of difference operators. We describe how the Stäckel transform acts and show that it preserves the structure equations.
San, Omer
2014-01-01
In this paper, a stabilized proper orthogonal decomposition (POD) reduced-order model (ROM) is presented for the barotropic vorticity equation. We apply the POD-ROM model to mid-latitude simplified oceanic basins, which are standard prototypes of more realistic large-scale ocean dynamics. A mode dependent eddy viscosity closure scheme is used to model the effects of the discarded POD modes. A sensitivity analysis with respect to the free eddy viscosity stabilization parameter is performed for various POD-ROMs with different numbers of POD modes. The POD-ROM results are validated against the Munk layer resolving direct numerical simulations using a fully conservative fourth-order Arakawa scheme. A comparison with the standard Galerkin POD-ROM without any stabilization is also included in our investigation. Significant improvements in the accuracy over the standard Galerkin model are shown for a four-gyre ocean circulation problem. This first step in the numerical assessment of the POD-ROM shows that it could r...
Second-order relational manipulations affect both humans and monkeys.
Christoph D Dahl
Full Text Available Recognition and individuation of conspecifics by their face is essential for primate social cognition. This ability is driven by a mechanism that integrates the appearance of facial features with subtle variations in their configuration (i.e., second-order relational properties into a holistic representation. So far, there is little evidence of whether our evolutionary ancestors show sensitivity to featural spatial relations and hence holistic processing of faces as shown in humans. Here, we directly compared macaques with humans in their sensitivity to configurally altered faces in upright and inverted orientations using a habituation paradigm and eye tracking technologies. In addition, we tested for differences in processing of conspecific faces (human faces for humans, macaque faces for macaques and non-conspecific faces, addressing aspects of perceptual expertise. In both species, we found sensitivity to second-order relational properties for conspecific (expert faces, when presented in upright, not in inverted, orientation. This shows that macaques possess the requirements for holistic processing, and thus show similar face processing to that of humans.
Relative Stability of cis- and trans-Hydrindanones
Motoo Tori
2015-01-01
Full Text Available The relative stabilities of several cis- and trans-hydrindanones were compared using both isomerization experiments and MM2 calculations. The generally believed rule that cis-hydrindanones are more stable than trans-isomers is applicable, but is not always true. This review introduces examples, mainly from studies in our laboratory, to explain these facts.
Striolo, Alberto; Luu, Xuan-Cuong; Molecular Science and Engineering Team
2013-03-01
Pickering emulsions find applications, e.g., in food processing, personal care products, and drug delivery. The emulsions stability is naturally related to the structural and dynamical properties of the nanoparticles adsorbed at oil-water interfaces. Such properties are investigated here by means of dissipative particle dynamics simulations, informed by atomistic molecular dynamics simulations results (Langmuir2011, 27, (9), 5264-5274). Several nanoparticles are considered, including Janus and homogeneous, and of several different shapes (spherical, elliptical, discoid, etc.) Structural and transport properties are quantified as a function of surface density and system composition. Results for radial distribution functions, hexagonal order parameters, and self-diffusion coefficients are reported. We sometimes find unexpected behavior. For example, self-diffusion coefficient maxima are observed in mixed systems. Implications of such observations on macroscopic observables (i.e., the stability of Pickering emulsions) are discussed. Acknowledgments: NSF
Cross-Order Integral Relations from Maximal Cuts
Johansson, Henrik; Larsen, Kasper J.; Søgaard, Mads
2015-01-01
We study the ABDK relation using maximal cuts of one- and two-loop integrals with up to five external legs. We show how to find a special combination of integrals that allows the relation to exist, and how to reconstruct the terms with one-loop integrals squared. The reconstruction relies on the observation that integrals across different loop orders can have support on the same generalized unitarity cuts and can share global poles. We discuss the appearance of nonhomologous integration contours in multivariate residues. Their origin can be understood in simple terms, and their existence enables us to distinguish contributions from different integrals. Our analysis suggests that maximal and near-maximal cuts can be used to infer the existence of integral identities more generally.
On the order equivalence relation of binary association measures
Paradowski Mariusz
2015-09-01
Full Text Available Over a century of research has resulted in a set of more than a hundred binary association measures. Many of them share similar properties. An overview of binary association measures is presented, focused on their order equivalences. Association measures are grouped according to their relations. Transformations between these measures are shown, both formally and visually. A generalization coefficient is proposed, based on joint probability and marginal probabilities. Combining association measures is one of recent trends in computer science. Measures are combined in linear and nonlinear discrimination models, automated feature selection or construction. Knowledge about their relations is particularly important to avoid problems of meaningless results, zeroed generalized variances, the curse of dimensionality, or simply to save time
DYNAMICAL STABILITY OF VISCOELASTIC COLUMN WITH FRACTIONAL DERIVATIVE CONSTITUTIVE RELATION
李根国; 朱正佑; 程昌钧
2001-01-01
The dynamic stability of simple supported viscoelastic column, subjected to a periodic axial force, is investigated. The viscoelastic material was assumed to obey the fractional derivative constitutive relation. The governing equation of motion was derived as a weakly singular Volterra integro-partial-differential equation, and it was simplified into a weakly singular Volterra integro-ordinary-differential equation by the Galerkin method. In terms of the averaging method, the dynamical stability was analyzed. A new numerical method is proposed to avoid storing all history data. Numerical examples are presented and the numerical results agree with the analytical ones.
INTERNATIONAL SECURITY RELATIONS AND POST-IMPERIAL ORDERS
Radu-Sebastian UNGUREANU
2011-08-01
Full Text Available This paper intends to investigate the relations between former imperial powers and new sovereign states succeeding an empire in the field of international security, particularly when involving the use of force. Despite their stated attachment to the normative principles of what we usually call “Westphalian order”, former imperial powers continue to interfere in the domestic affairs of these new states, especially those unable to exercise their sovereignty efficiently and legitimately. One could say that, by military interventions, these powers deny the sovereignty of weak states in the regions once under their control; but the preparation of these missions makes the actions not to be interpreted as expressions of an imperialist attitude. I consider there are two major ideal-types that could better explain such interventions. In a power-oriented post-imperial order, the intervention of a former empire is the result of the projection of its national interests and identities. In a norm-oriented post-imperial order, the sense of moral responsibility of the former imperial power is the main reason for its interference. The intervention’s legitimacy and suitability require domestic and international support. This paper, grounded on a constructivist approach, intends to contribute to the understanding of international security issues in terms of a world shaped by actors’ interests and identities and the dynamics of their relations. The identified ideal-types of post-imperial orders consider both material and cultural factors. The analytical elements that may link extremely different situations are the socially variable interpretations of past and present.
Stabilization and control of fractional order systems a sliding mode approach
Bandyopadhyay, Bijnan
2015-01-01
In the last two decades fractional differential equations have been used more frequently in physics, signal processing, fluid mechanics, viscoelasticity, mathematical biology, electro chemistry and many others. It opens a new and more realistic way to capture memory dependent phenomena and irregularities inside the systems by using more sophisticated mathematical analysis.This monograph is based on the authors' work on stabilization and control design for continuous and discrete fractional order systems. The initial two chapters and some parts of the third chapter are written in tutorial fashi
Next-to-Next-Leading Order analysis of electroweak vacuum stability and rising inflection point
Iacobellis, Giuseppe
2016-01-01
We show an analysis on the gauge-independent observables associated with two stationary configurations of the Standard Model (SM) potential (extrapolated to high energy at Next-to-Next-to-Leading-Order (NNLO)): i) the value of the top mass ensuring stability of the SM electroweak vacuum and ii) the value of the Higgs potential at a rising inflection point. We examine in detail and reappraise the experimental and theoretical uncertainties which plague their determination, keeping alive the possibility for the SM of being stable and studying applications of such configuration to models of primordial inflation.
Prill, Dennis; Class, Andreas G. [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). AREVA Nuclear Professional School (ANPS)
2013-07-01
Unexpected non-linear boiling water reactor (BWR) instability events in various plants, e.g. LaSalle II in 1988 and Oskarshamn II in 1990 amongst others, emphasize the major safety relevance and the existence of parameter regions with unstable behavior. A detailed description of the complete dynamical non-linear behavior is of paramount importance for BWR operation. An extension of state-of-the-art methodology towards a more general stability description, also applicable in the non-linear region, could lead to a deeper understanding of non-linear BWR stability phenomena. With the intention of a full non-linear stability analysis of the two-phase BWR system, the present paper aims at a general non-linear methodology capable to achieve reliable and numerical stable reduced order models (ROMs), representing the dynamical behavior of an original system based on a small number of transients. Model-specific options and aspects of the proposed methodology are focused on and illustrated by means of a strongly non-linear dynamical system showing complex oscillating behavior. Prediction capability of the proposed methodology is also addressed. (orig.)
Letchmanan, Kumaran; Shen, Shou-Cang; Ng, Wai Kiong; Tan, Reginald B H
2015-01-01
Dissolution of poorly water-soluble drug, Artemisinin (ART), was enhanced by encapsulating the drug particles inside pore channels of ordered mesoporous silica, SBA-15, via co-spray drying. The drug release profiles of ART were investigated by using flow-through cell (USP IV) and in vitro dissolution tester (USP II). The co-spray-dried ART/SBA-15 samples demonstrated significantly improved dissolution rates and supersaturation compared to the untreated ART. The low cytotoxicity effect of ART and SBA-15 on Caco-2 cells after 24 h incubation demonstrated the biocompatibility of ART/SBA-15. Finally, the storage stability of the samples was investigated for 6 months under five different storage conditions. Overall, the solid dispersions exhibited excellent physical stability; however, their chemical stability was affected by humidity regardless of storage temperatures. The formulation of solid dispersions of ART/SBA-15 is potentially safe and an effective approach to enhance the solubility of poorly water-soluble ART.
Zylberman, V.; Craig, P.O.; Klinke, S.; Cauerhff, A.; Goldbaum, F.A. [Instituto Leloir, Buenos Aires (Argentina); Braden, B.C. [Bowie State Univ., Maryland (United States)
2004-07-01
The penultimate step in the pathway of riboflavin biosynthesis is catalyzed by the enzyme lumazine synthase (LS). One of the most distinctive characteristics of this enzyme is the structural quaternary divergence found in different species. The protein exists as pentameric and icosahedral forms, built from practically the same structural monomeric unit. The pentameric structure is formed by five 18 kDa monomers, each extensively contacting neighboring monomers. The icosahedral structure consists of 60 LS monomers arranged as twelve pentamers giving rise to a capsid exhibiting icosahedral 532 symmetry. In all lumazine synthases studied, the topologically equivalent active sites are located at the interfaces between adjacent subunits in the pentameric modules. The Brucella spp. lumazine synthase (BLS) sequence clearly diverges from pentameric and icosahedral enzymes. This unusual divergence prompted to further investigate on its quaternary arrangement. In the present work, we demonstrate by means of solution Light Scattering and X-ray structural analyses that BLS assembles as a very stable dimer of pentamers representing a third category of quaternary assembly for lumazine synthases. We also describe by spectroscopic studies the thermodynamic stability of this oligomeric protein, and postulate a mechanism for dissociation/unfolding of this macromolecular assembly. The higher molecular order of BLS increases its stability 20 deg C compared to pentameric lumazine synthases. The decameric arrangement described in this work highlights the importance of quaternary interactions in the stabilization of proteins. (author)
Stability Analysis of a Class of Second Order Sliding Mode Control Including Delay in Input
Pedro R. Acosta
2013-01-01
Full Text Available This paper deals with a class of second order sliding mode systems. Based on the derivative of the sliding surface, sufficient conditions are given for stability. However, the discontinuous control signal depend neither on the derivative of sliding surface nor on its estimate. Time delay in control input is also an important issue in sliding mode control for engineering applications. Therefore, also sufficient conditions are given for the time delay size on the discontinuous input signal, so that this class of second order sliding mode systems might have amplitude bounded oscillations. Moreover, amplitude of such oscillations may be estimated. Some numerical examples are given to validate the results. At the end, some conclusions are given on the possibilities of the results as well as their limitations.
The Order-Theoretic Origin of Special Relativity
Knuth, Kevin H.; Bahrenyi, Newshaw
2011-03-01
In this paper, we present a novel derivation of special relativity and the information physics of events. We postulate that events are fundamental, and that some events have the potential to be influenced by other events. However, this potential is not reciprocal, nor are all pairs of events related in such a way. This leads to the concept of a partially-ordered set of events, which is often called a causal set. Quantification proceeds by distinguishing two chains of coordinated events, each of which represents an observer, and assigning a numerical valuation to each chain. By projecting events onto each chain, each event can be quantified by a pair of numbers, referred to as a pair. We show that each pair can be decomposed into a sum of symmetric and antisymmetric pairs, which correspond to time-like and space-like coordinates. We show that one can map a pair to a scalar and that this gives rise to the Minkowski metric. The result is an observer-based theory of special relativity that quantifies events with pairs of numbers. Events are fundamental and space-time is an artificial construct designed to make events look simple.
Stacy, Erin Michele
2012-01-01
Soil erosion can alter the mechanisms of organic matter (OM) storage and persistence in soil, including aggregation, burial, and organo-mineral associations. I studied how extended transport of topsoil and associated OM alters OM stabilization mechanisms by comparing soil from different landform positions with sediment exported from eight, low-order watersheds in the Sierra Nevada, California. To assess the relative importance of different stabilization mechanisms, I separated free, unprotect...
Soft matter dispersions with ordered inner structures, stabilized by ethoxylated phytosterols.
Libster, Dima; Aserin, Abraham; Yariv, Doron; Shoham, Gil; Garti, Nissim
2009-11-01
This paper describes the formation and characterization of liquid crystalline dispersions based on the hexagonal phase of GMO/tricaprylin/water. As a stabilizer of the soft particles dispersed in the aqueous phase, a non-ionic, non-polymeric surfactant--ethoxylated phytosterol with 30 oxyethylene units (PhEO) was utilized. In contrast to Pluronic copolymers, normally utilized in the stabilization of liquid crystalline dispersions with ordered inner structure, use of such non-polymeric surfactant is not a common practice in this field. We revealed how properties of these particles, such as internal structure, size, and stability, can be rationally modified by the concentration of the stabilizing agent and processing conditions. The physical stability of the hexosomes was further examined by the LUMiFuge technique. Structural effect of PhEO solubilization on the properties of the bulk H(II) mesophase system showed that phase behavior was greatly influenced following phase transitions: H(II)-->H(II)+cubic-->cubic+L(alpha)-->L(alpha). The decrease of hydrogen bonding of the hydroxyl and carbonyl groups of monoolein with water and simultaneous hydration of EO groups of PhEO appeared to be important for the observed behavior. The use of PhEO as a dispersant resulted in a soft matter multi-phase water dispersion with bimodal distribution of the particle population. Effective stabilization of hexosomes was obtained in an extremely narrow concentration range of PhEO (0.1-0.2 wt%), coexisting with small vesicles and disordered particles. At higher PhEO content, particles had disordered inner structure, and unilamellar and multilamellar vesicles, at the expense of hexosomes in consequence of incorporation of the dispersant into the hexosome structure. PhEO was found to induce lamellar phase formation, introducing disorder into the hexagonal LLC and reducing their domain size. Finally, hexosomes were evaluated as delivery vehicles for the therapeutic peptide desmopressin
Order and phase stability in CoPt: the role of magnetism
Karoui, Sondes; Amara, Hakim; Ducastelle, Francois [LEM, ONERA-CNRS, BP72 92322 Chatillon Cedex (France); Legrand, Bernard [SRMP, CEA, Saclay (France)
2011-07-01
Transition metal nano-alloys (FePd, CoRh, and CoPt) are innovative new materials whose size and chemical composition govern their physical and chemical properties. CoPt, the focus point of this study, had been duly studied in the bulk phase both experimentally and theoretically. There exists a large array of results that clearly hint at the importance of magnetism, and the stabilization that it brings to the system. Indeed, we strongly believe that the crystallographic order present in CoPt can be attributed to the alloy's inherent magnetic character. To point out this effect, Density Functional Theory calculations have been performed using the ABINIT code with and without magnetism. We report on the influence of spin polarized calculations on structure stabilization in bulk Co and Pt as well as the alloy's various crystallographic phases: ordered L1o, L12, and disordered FCC. This approach corresponds to a quantitative first step towards better understanding the role of magnetism at the atomic scale.
Yuan Guangwei; Sheng Zhiqiang; Hang Xudeng
2007-01-01
For solving nonlinear parabolic equation on massive parallel computers,the construction of parallel difference schemes with simple design, high parallelism and unconditional stability and second order global accuracy in space, has long been desired.In the present work, a new kind of general parallel difference schemes for the nonlinear parabolic system is proposed. The general parallel difference schemes include, among others, two new parallel schemes. In one of them, to obtain the interface values on the interface of sub-domains an explicit scheme of Jacobian type is employed, and then the fully implicit scheme is used in the sub-domains. Here, in the explicit scheme of Jacobian type, the values at the points being adjacent to the interface points are taken as the linear combination of values of previous two time layers at the adjoining points of the inner interface. For the construction of another new parallel difference scheme,the main procedure is as follows. Firstly the linear combination of values of previous two time layers at the interface points among the sub-domains is used as the (Dirichlet)boundary condition for solving the sub-domain problems. Then the values in the subdomains are calculated by the fully implicit scheme. Finally the interface values are computed by the fully implicit scheme, and in fact these calculations of the last step are explicit since the values adjacent to the interface points have been obtained in the previous step. The existence, uniqueness, unconditional stability and the second order accuracy of the discrete vector solutions for the parallel difference schemes are proved.Numerical results are presented to examine the stability, accuracy and parallelism of the parallel schemes.
Stability of multiquadric quasi-interpolation to approximate high order derivatives
无
2010-01-01
Numerical simulation of the high order derivatives based on the sampling data is an important and basic problem in numerical approximation,especially for solving the differential equations numerically.The classical method is the divided difference method.However,it has been shown strongly unstable in practice.Actually,it can only be used to simulate the lower order derivatives in applications.To simulate the high order derivatives,this paper suggests a new method using multiquadric quasi-interpolation.The stability of the multiquadric quasi-interpolation method is compared with the classical divided difference method.Moreover,some numerical examples are presented to confirm the theoretical results.Both theoretical results and numerical examples show that the multiquadric quasi-interpolation method is much stabler than the divided difference method.This property shows that multiquadric quasi-interpolation method is an efficient tool to construct an approximation of high order derivatives based on scattered sampling data even with noise.
Synthesis of ordered mesoporous γ-Al2O3:Eu3+ with high luminous performance and thermal stability
YU Caixia; YANG Qu; SHA Lei; LIU Yingliang
2011-01-01
An efficient and convenient one-step process was developed for synthesizing nev effective red luminous materials through ordered mesoporous γ-alumina assembling with Eu3+.Employing P123 as a structure-directing agent and hydrochloric acid,citric acid as pH adjustor,ordered mesoporous γ-alumina was fabricated by simple sol-gel method.The pore structure was characterized by X-ray diffraction (XRD),N2 adsorption-desorption isotherms and transmission electron microscopy (TEM).The as-synthesized γ-aluminas had narrow pore-size distribution (5-7 nm),large surface area (246 m2/g) and high thermal stability (750-1000 ℃).The luminous property of materials was characterized by Photoluminescence (PL) spectra.The γ-Al2O3;Eu3+ materials had efficient luminescence,and the emission strength was related to the content of Eu3+.
[Social order, stability, and certainty violence and social power in early modern history].
Pröve, Ralf
2014-01-01
This article develops a comprehensive critique of historical research focussing on the mutual relations between social power and violence. According to the methodological initial hypothesis, due to the inadequate distinction between indigenious concept (from sources) and heuristic (from reseach) in the historical sciences, there have been very few valuable insights into these relations to date. In order to expand the research focus which is the objective of this article, the analysis draws on the two actor-centric reference systems of "certainty" and "order". The key idea behind this, operationalizing certainty/uncertainty by means of order/disorder, is a promising way of programmatically combining a vertical and horizontal network of relationships of power, violence, certainty, and order.
Boclair, J. W.; Braterman, P. S.
1999-01-01
Solutions containing di- and trivalent metal chlorides [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+; M(III) = Al3+, Fe3+] were titrated with NaOH to yield hydrotalcite-like layered double hydroxides (LDH), [[M(II)]1-x[M(III)]x(OH)2][Cl]x yH2O, by way of M(III) hydroxide/hydrous oxide intermediates. Analysis of the resultant titration curves yields nominal solubility constants for the LDH. The corresponding LDH stabilities are in the order Mg hydroxides/hydrous oxides is discussed.
New Stability Criteria for High-Order Neural Networks with Proportional Delays
Xu, Chang-Jin; Li, Pei-Luan
2017-03-01
This paper is concerned with high-order neural networks with proportional delays. The proportional delay is a time-varying unbounded delay which is different from the constant delay, bounded time-varying delay and distributed delay. By the nonlinear transformation {y}i(t)={u}i({{{e}}}t){{ }}(i=1,2,\\ldots ,n), we transform a class of high-order neural networks with proportional delays into a class of high-order neural networks with constant delays and time-varying coefficients. With the aid of Brouwer fixed point theorem and constructing the delay differential inequality, we obtain some delay-independent and delay-dependent sufficient conditions to ensure the existence, uniqueness and global exponential stability of equilibrium of the network. Two examples with their simulations are given to illustrate the theoretical findings. Our results are new and complement previously known results. Supported by National Natural Science Foundation of China under Grant Nos. 61673008 and 11261010, and Project of High-level Innovative Talents of Guizhou Province ([2016]5651)
First order resonance overlap and the stability of close two planet systems
Deck, Katherine M; Holman, Matthew J
2013-01-01
Motivated by the population of multi-planet systems with orbital period ratios 1
Improved convergence and stability properties in a three-dimensional higher-order ice sheet model
J. J. Fürst
2011-12-01
Full Text Available We present a finite difference implementation of a three-dimensional higher-order ice sheet model. In comparison to a conventional centred difference discretisation it enhances both numerical stability and convergence. In order to achieve these benefits the discretisation of the governing force balance equation makes extensive use of information on staggered grid points. Using the same iterative solver, a centred difference discretisation that operates exclusively on the regular grid serves as a reference. The reprise of the ISMIP-HOM experiments indicates that both discretisations are capable of reproducing the higher-order model inter-comparison results. This setup allows a direct comparison of the two numerical implementations also with respect to their convergence behaviour. First and foremost, the new finite difference scheme facilitates convergence by a factor of up to 7 and 2.6 in average. In addition to this decrease in computational costs, the accuracy for the resultant velocity field can be chosen higher in the novel finite difference implementation. Changing the discretisation also prevents build-up of local field irregularites that occasionally cause divergence of the solution for the reference discretisation.
The improved behaviour makes the new discretisation more reliable for extensive application to real ice geometries. Higher accuracy and robust numerics are crucial in time dependent applications since numerical oscillations in the velocity field of subsequent time steps are attenuated and divergence of the solution is prevented.
Short-Range-Order Mineral Physical Protection On Black Carbon Stabilization
Liang, B.; Weng, Y. T.; Wang, C. C.; Song, Y. F.; Lehmann, J.; Wang, C. H.
2015-12-01
Soil organic matter is one of the largest reservoirs in global carbon cycle, and black carbon (BC) represents a chemical resistant component. Black C plays an important role in global climate change. Generally considered recalcitrant due to high aromaticity, the reactive surface and functional groups of BC are crucial for carbon sequestration in soils. Mineral sorption and physical protection is an important mechanism for BC long term stabilization and sequestration in environments. Previous studies on mineral protection of BC were limited to analysis techniques in two-dimensions, for example, by SEM, TEM, and NanoSIMS. Little is known about the scope of organo-mineral association, the in-situ distribution and forms of minerals, and the ultimate interplay of BC and minerals. The aim of this study is to investigate the three-dimensional interaction of organic C and minerals in submicron scale using synchrotron-based Transmission X-ray Microcopy (TXM) and Fourier-Transform Infrared Spectroscopy (FTIR). Abundant poorly-crystallined nano-minerals particles were observed. These short-range-order (SRO) minerals also aggregate into clusters and sheets, and form envelops-like structures on the surface of BC. On top of large surface contact area, the intimate interplay between BC and minerals reinforces the stability of both organic C and minerals, resulting from chemical bonding through cation bridging and ligand exchange. The mineral protection enhances BC stabilization and sequestration and lowers its bioavailability in environment. The results suggest that mineral physical protection for BC sequestration may be more important than previous understanding.
Janusz Brzdęk
2010-01-01
Full Text Available We prove the Hyers-Ulam stability of a second-order linear functional equation in single variable (with constant coefficients that is connected with the Fibonacci numbers and Lucas sequences. In this way we complement, extend, and/or improve some recently published results on stability of that equation.
Yamamoto, T.; Brewster, R.; Safran, S. A.
2010-07-01
We use a liquid-crystal model to predict that hybrid lipids (lipids that have one saturated and one unsaturated tail) can stabilize line interfaces between domains in mixed membranes of saturated lipids, hybrid lipids, and cholesterol (SHC membranes). The model predicts the phase separation of SHC membranes with both parabolic and loop binodals depending on the cholesterol concentration, modeled via an effective pressure. In some cases, the hybrid lipids can reduce the line tension to zero in SHC membranes at temperatures that approach the critical temperature as the pressure is increased. The differences in the hybrid saturated tail conformational order in bulk and at the interface are responsible for the reduction of the line tension.
Asymptotic behavior and stability of second order neutral delay differential equations
Chen, G.L.; van Gaans, O.W.; Verduyn Lunel, Sjoerd
2014-01-01
We study the asymptotic behavior of a class of second order neutral delay differential equations by both a spectral projection method and an ordinary differential equation method approach. We discuss the relation of these two methods and illustrate some features using examples. Furthermore, a fixed
Altay, G.; Dökmeci, M. C.
2014-09-01
The relative merit of lower-order theories, which have been deduced from the three-dimensional theories of continua, is evaluated with respect to the quantified and un-quantified errors in mathematically modeling the physical response of structural elements. Then, the one-dimensional theories are derived with high accuracy, internal consistency and flexibility from the three-dimensional theory of elasticity in order to govern the nonlinear and incremental motions and stability of a functionally graded rod. First, a kinematic-based method of separation of variables is introduced as a method of reduction, which may lead to the lower-order theories with the same order of errors of the three-dimensional theories, and the nonlinear theories of the rod are derived under Leibnitz's postulate of structural elements by use of Hamilton's principle. A theorem of uniqueness is proved in solutions of the linear equations of the rod by means of the logarithmic convexity argument. Next, the kinematic basis is expressed by the power series expansion in the cross-sectional coordinates using Weierstrass's theorem. Mindlin's method is used so as to derive the equations in an invariant and fully variational form for the small motions superposed on a static finite deformation, the stability analysis and the high-frequency vibrations of the rod. Moreover, the free vibrations of the rod are considered, the basic properties of eigenvalues are examined, and Rayleigh's quotient is obtained. The invariant equations of the rod, which are expressible in any system of orthogonal coordinates, may provide simultaneous approximations on all the field variables in a direct method of solutions. The equations are indicated to contain some of earlier equations of rods, as special cases, and also, the numerical elasticity solution of a sample application is presented.
Gauge stability of 3+1 formulations of General Relativity
Khokhlov, A M
2002-01-01
We present a general approach to the analysis of gauge stability of 3+1 formulations of General Relativity (GR). Evolution of coordinate perturbations and the corresponding perturbations of lapse and shift can be described by a system of eight quasi-linear partial differential equations. Stability with respect to gauge perturbations depends on a choice of gauge and a background metric, but it does not depend on a particular form of a 3+1 system if its constrained solutions are equivalent to those of the Einstein equations. Stability of a number of known gauges is investigated in the limit of short-wavelength perturbations, and a physical meaning of gauge instabilities is discussed. All fixed gauges except a synchronous gauge are found to be ill-posed. A necessary condition is derived for well-posedness of metric-dependent algebraic gauges. These gauges are found, however, to be generally unstable with respect to perturbations of physical accelerations caused by deformations of reference frames. A maximal slic...
曾庆山; 曹广益; 朱新坚
2004-01-01
The definitions of controllability, observability and stability were presented for fractional-order linear systems. Using the Cayley-Hamilton theorem and Mittag-Leffler function in two parameters, the sufficient and necessary conditions of controllability and observability for such systems were derived. In terms of Lyapunov's stability theory, using the theorems of Mittage-Leffler function in two parameters this paper directly derived the sufficient and necessary condition of stability for such systems. The results obtained are useful for the analysis and synthesis of fractional-order linear control systems.
Stability analysis of liver cancer-related microRNAs
Yan Li; Zhenggang Jiang; Lijian Xu; Hu Yao; Jiangfeng Guo; Xianfeng Ding
2011-01-01
MicroRNAs(miRNAs)are non-coding,single-stranded RNAs of ～22 nt and constitute a novel class of gene regulators that are found in both plants and animals.Several studies have demonstrated that serum miRNAs could serve as potential biomarkers for the detection of various cancers and other diseases.A few documents regarding the stability of liver cancer-related miRNAs in serum are available.A systemic analysis of the stability of miRNA in serum is quite necessary.The purpose of this study was to evaluate the stability of miRNAs from three different sources,cultured liver cancer Huh-7 cell line,clinical liver cancer,and serum under different experimental conditions,including different temperature,time duration,pH values,Rnase A digestion,Dnase Ⅰ digestion,and various freeze-thaw cycles.The qRT-PCR analysis demonstrated that liver cancer-related miRNAs were detectable under each of test conditions,indicating that miRNAs were extremely stable and resistant to destruction and degradation under harsh environmental conditions.However,ribosomal RNA was fragile and easily degraded by demonstrating sharp decrease of relative expression under the non-physiological test conditions.We also established a robust procedure for serum RNA extraction,which is greatly important not only for the miRNA profiling studies bat also for the disease prognosis based on abnormal miRNA expression.
Mean square stability of a second-order parametric linear system excited by a colored Gaussian noise
Floris, Claudio
2015-02-01
The stochastic stability of a second-order linear parametric oscillator whose stiffness is perturbed by a stationary zero-mean colored Gaussian process is investigated in this paper referring to the stability in the second response moments (mean square stability). The stochastic perturbation is the output of a linear filter excited by a stationary Gaussian white noise stochastic process, and the hypothesis of weak excitation is not formulated. The first assumption allows using Itô's stochastic differential calculus. The moment equations of the response are written till the second order by means of Itô's differential rule. They form an infinite hierarchy, that is the equations for the moments of order r contain moments of order larger than r. In order to close the hierarchy, the cumulant neglect closure method is applied herein. The moment equation set is closed by neglecting the cumulants of third order. Nonlinear moment equations result: they are linearized, and the limit of stability is searched by studying the eigenvalues of the matrix of the coefficients of the linearized moment equations. Several numerical analyses are performed to evaluate the critical mean square value of the excitation when a system parameter is varied for the cases of both first and second-order parametric excitation. A first-order excitation, an Ornstein-Uhlenbeck process, does not cause stochastic resonance, while a second-order excitation does. The first result was not known previously.
Disruption of Relational Processing Underlies Poor Memory for Order
Jonker, Tanya R.; MacLeod, Colin M.
2015-01-01
McDaniel and Bugg (2008) proposed that relatively uncommon stimuli and encoding tasks encourage elaborative encoding of individual items (item-specific processing), whereas relatively typical or common encoding tasks encourage encoding of associations among list items (relational processing). It is this relational processing that is thought to…
Educational Needs of Women in Relation to Postpartum Religious Orders
Beigi, Marjan; Nekuei, Nafisehsadat
2017-01-01
Introduction: Religious orders are one of the educational needs of the postpartum period. This study was conducted to determine the educational needs of postpartum religious orders. Materials and Methods: This cross-sectional study was conducted among 421 postpartum women and 15 specialists. Quota random sampling was conducted from January to March 2014 in Isfahan, Iran. Data analysis was performed using the Statistical Package for the Social Sciences software and statistical methods. Results...
Improved convergence and stability properties in a three-dimensional higher-order ice sheet model
J. J. Fürst
2011-07-01
Full Text Available We present a novel finite difference implementation of a three-dimensional higher-order ice sheet model that performs well both in terms of convergence rate and numerical stability. In order to achieve these benefits the discretisation of the governing force balance equation makes extensive use of information on staggered grid points. Using the same iterative solver, an existing discretisation that operates exclusively on the regular grid serves as a reference. Participation in the ISMIP-HOM benchmark indicates that both discretisations are capable of reproducing the higher-order model inter-comparison results. This allows a direct comparison not only of the resultant velocity fields but also of the solver's convergence behaviour which holds main differences. First and foremost, the new finite difference scheme facilitates convergence by a factor of up to 7 and 2.6 in average. In addition to this decrease in computational costs, the precision for the resultant velocity field can be chosen higher in the novel finite difference implementation. For high precisions, the old discretisation experiences difficulties to converge due to large variation in the velocity fields of consecutive Picard iterations. Finally, changing discretisation prevents build-up of local field irregularites that occasionally cause divergence of the solution for the reference discretisation.
The improved behaviour makes the new discretisation more reliable for extensive application to real ice geometries. Higher precision and robust numerics are crucial in time dependent applications since numerical oscillations in the velocity field of subsequent time steps are attenuated and divergence of the solution is prevented. Transient applications also benefit from the increased computational efficiency.
Continued stabilization of the nuclear higher-order structure of post-mitotic neurons in vivo.
Janeth Alva-Medina
Full Text Available BACKGROUND: Cellular terminal differentiation (TD correlates with a permanent exit from the cell cycle and so TD cells become stably post-mitotic. However, TD cells express the molecular machinery necessary for cell proliferation that can be reactivated by experimental manipulation, yet it has not been reported the stable proliferation of any type of reactivated TD cells. Neurons become post-mitotic after leaving the ventricular zone. When neurons are forced to reenter the cell cycle they invariably undergo cell death. Wider evidence indicates that the post-mitotic state cannot solely depend on gene products acting in trans, otherwise mutations in the corresponding genes may lead to reentry and completion of the cell cycle in TD cells, but this has not been observed. In the interphase, nuclear DNA of metazoan cells is organized in supercoiled loops anchored to a nuclear nuclear matrix (NM. The DNA-NM interactions define a higher-order structure in the cell nucleus (NHOS. We have previously compared the NHOS of aged rat hepatocytes with that of early post-mitotic rat neurons and our results indicated that a very stable NHOS is a common feature of both senescent and post-mitotic cells in vivo. PRINCIPAL FINDINGS: In the present work we compared the NHOS in rat neurons from different post-natal ages. Our results show that the trend towards further stabilization of the NHOS in neurons continues throughout post-natal life. This phenomenon occurs in absence of overt changes in the post-mitotic state and transcriptional activity of neurons, suggesting that it is independent of functional constraints. CONCLUSIONS: Apparently the continued stabilization of the NHOS as a function of time is basically determined by thermodynamic and structural constraints. We discuss how the resulting highly stable NHOS of neurons may be the structural, non-genetic basis of their permanent and irreversible post-mitotic state.
Continued Stabilization of the Nuclear Higher-Order Structure of Post-Mitotic Neurons In Vivo
Alva-Medina, Janeth; Maya-Mendoza, Apolinar; Dent, Myrna A. R.; Aranda-Anzaldo, Armando
2011-01-01
Background Cellular terminal differentiation (TD) correlates with a permanent exit from the cell cycle and so TD cells become stably post-mitotic. However, TD cells express the molecular machinery necessary for cell proliferation that can be reactivated by experimental manipulation, yet it has not been reported the stable proliferation of any type of reactivated TD cells. Neurons become post-mitotic after leaving the ventricular zone. When neurons are forced to reenter the cell cycle they invariably undergo cell death. Wider evidence indicates that the post-mitotic state cannot solely depend on gene products acting in trans, otherwise mutations in the corresponding genes may lead to reentry and completion of the cell cycle in TD cells, but this has not been observed. In the interphase, nuclear DNA of metazoan cells is organized in supercoiled loops anchored to a nuclear nuclear matrix (NM). The DNA-NM interactions define a higher-order structure in the cell nucleus (NHOS). We have previously compared the NHOS of aged rat hepatocytes with that of early post-mitotic rat neurons and our results indicated that a very stable NHOS is a common feature of both senescent and post-mitotic cells in vivo. Principal Findings In the present work we compared the NHOS in rat neurons from different post-natal ages. Our results show that the trend towards further stabilization of the NHOS in neurons continues throughout post-natal life. This phenomenon occurs in absence of overt changes in the post-mitotic state and transcriptional activity of neurons, suggesting that it is independent of functional constraints. Conclusions Apparently the continued stabilization of the NHOS as a function of time is basically determined by thermodynamic and structural constraints. We discuss how the resulting highly stable NHOS of neurons may be the structural, non-genetic basis of their permanent and irreversible post-mitotic state. PMID:21731716
Structure, chemical ordering and thermal stability of Pt-Ni alloy nanoclusters.
Cheng, Daojian; Yuan, Shuai; Ferrando, Riccardo
2013-09-01
Equilibrium structures, chemical ordering and thermal properties of Pt-Ni nanoalloys are investigated by using basin hopping-based global optimization, Monte Carlo (MC) and molecular dynamics (MD) methods, based on the second-moment approximation of the tight-binding potentials (TB-SMA). The TB-SMA potential parameters for Pt-Ni nanoalloys are fitted to reproduce the results of density functional theory calculations for small clusters. The chemical ordering in cuboctahedral (CO) Pt-Ni nanoalloys with 561 and 923 atoms is obtained from the so called semi-grand-canonical ensemble MC simulation at 100 K. Two ordered phases of L12 (PtNi3) and L10 (PtNi) are found for the CO561 and CO923 Pt-Ni nanoalloys, which is in good agreement with the experimental phase diagram of the Pt-Ni bulk alloy. In addition, the order-disorder transition and thermal properties of these nanoalloys are studied by using MC and MD methods, respectively. It is shown that the typical perfect L10 PtNi structure is relatively stable, showing high order-disorder transition temperature and melting point among these CO561 and CO923 Pt-Ni nanoalloys.
A numerical investigation for robust stability of fractional-order uncertain systems.
Senol, Bilal; Ates, Abdullah; Alagoz, B Baykant; Yeroglu, Celaleddin
2014-03-01
This study presents numerical methods for robust stability analysis of closed loop control systems with parameter uncertainty. Methods are based on scan sampling of interval characteristic polynomials from the hypercube of parameter space. Exposed-edge polynomial sampling is used to reduce the computational complexity of robust stability analysis. Computer experiments are used for demonstration of the proposed robust stability test procedures.
Birth Order, Sibling IQ Differences, and Family Relations.
Pfouts, Jane H.
The differential impact of birth order and IQ on sibling roles were examined with particular interest focused on achievement outcomes. Subjects were a stratified sample of 37 pairs of near-in-age siblings, all within the normal range in personality and IQ, but differing significantly in scores on the Slosson IQ Test. Results indicate that when the…
Wu, Ailong; Liu, Ling; Huang, Tingwen; Zeng, Zhigang
2017-01-01
Neurodynamic system is an emerging research field. To understand the essential motivational representations of neural activity, neurodynamics is an important question in cognitive system research. This paper is to investigate Mittag-Leffler stability of a class of fractional-order neural networks in the presence of generalized piecewise constant arguments. To identify neural types of computational principles in mathematical and computational analysis, the existence and uniqueness of the solution of neurodynamic system is the first prerequisite. We prove that the existence and uniqueness of the solution of the network holds when some conditions are satisfied. In addition, self-active neurodynamic system demands stable internal dynamical states (equilibria). The main emphasis will be then on several sufficient conditions to guarantee a unique equilibrium point. Furthermore, to provide deeper explanations of neurodynamic process, Mittag-Leffler stability is studied in detail. The established results are based on the theories of fractional differential equation and differential equation with generalized piecewise constant arguments. The derived criteria improve and extend the existing related results.
Positive representations of general commutation relations allowing Wick ordering
Jorgensen, P E T; Werner, R F
1993-01-01
where the $T_{ij}^{k\\ell}$ are essentially arbitrary scalar coefficients. Examples comprise the $q$-canonical commutation relations introduced by Greenberg, Bozejko, and Speicher, and the twisted canonical (anti-)commutation relations studied by Pusz and Woronowicz, as well as the quantum group S$_\
Sino-Russian Relations in a Changing World Order
2013-01-01
state sovereignty over internal affairs and a condominium of great powers, represented by the Security Council, to negotiate world trouble spots...addition, throughout the 1990s and early 2000s, the Russian defense industry was desperate for orders and cash. China wanted advanced weapons systems ...arenas. Today, however, apart from nuclear forces and the technological sophistication of some major weapons systems , China is ascendant in the
Sino-Russian Relations in a Changing World Order
2014-01-01
It also includes the development of multilateral organi- zations that exclude the West, such as the BRICS (Brazil, Russia, India, China, and South...on world order. In fact, Russia is overshadowed by more powerful states in most multilateral forums, including the G8 and BRICS gatherings...February 2014, http://blogs.ft.com/beyond- brics /2014/02/27/ukraine-a-setback-in -chinas-eastern-europe-strategy/?. 15. See, for example, “Backing
The relation of collapsibility and confounding to faithfulness and stability.
Mansournia, Mohammad Ali; Greenland, Sander
2015-07-01
A probability distribution may have some properties that are stable under a structure (e.g., a causal graph) and other properties that are unstable. Stable properties are implied by the structure and thus will be shared by populations following the structure. In contrast, unstable properties correspond to special circumstances that are unlikely to be replicated across those populations. A probability distribution is faithful to the structure if all independencies in the distribution are logical consequences of the structure. We explore the distinction between confounding and noncollapsibility in relation to the concepts of faithfulness and stability. Simple collapsibility of an odds ratio over a risk factor is unstable and thus unlikely if the exposure affects the outcome, whether or not the risk factor is associated with exposure. For a binary exposure with no effect, collapsibility over a confounder also requires unfaithfulness. Nonetheless, if present, simple collapsibility of the odds ratio limits the degree of confounding by the covariate. Collapsibility of effect measures is stable if the covariate is independent of the outcome given exposure, but it is unstable if the covariate is an instrumental variable. Understanding stable and unstable properties of distributions under causal structures, and the distinction between stability and faithfulness, yields important insights into the correspondence between noncollapsibility and confounding.
Karafyllis, Iasson
2010-01-01
Sampling arises simultaneously with input and output delays in networked control systems. When the delay is left uncompensated, the sampling period is generally required to be sufficiently small, the delay sufficiently short, and, for nonlinear systems, only semiglobal practical stability is generally achieved. For example, global stabilization of strict-feedforward systems under sampled measurements, sampled-data stabilization of the nonholonomic unicycle with arbitrarily sparse sampling, and sampled-data stabilization of LTI systems over networks with long delays, are open problems. In this paper we present two general results that address these example problems as special cases. First, we present global asymptotic stabilizers for forward complete systems under arbitrarily long input and output delays, with arbitrarily long sampling periods, and with continuous application of the control input. Second, we consider systems with sampled measurements and with control applied through a zero-order hold, under th...
Control design for the SISO system with the unknown order and the unknown relative degree.
Zhao, Chunzhe; Li, Donghai
2014-07-01
For the uncertain system whose order, relative degree and parameters are unknown in the control design, new research is still in need on the parameter tuning and close-loop stability. During the last 10 years, much progress is made in the application and theory research of the active disturbance rejection control (ADRC) for the uncertain system. In this study, the necessary and sufficient conditions are established for building the ADRC for the minimum-phase system and the open-loop stable system when the plant parameters, orders and relative degrees are unknown, the corresponding ideal dynamics are analyzed, and the theoretical results are verified by the simulations. Considering the wide application and the long history of the PID/PI controller, a method is given to design ADRC quickly based on the existing (generalized or conventional) PID/PI controller. A plenty of simulations are made to illustrate this PID/PI-based design method and the corresponding close-loop performances. The simulation examples include the minimum/nonminimum-phase plants, the stable/integrating plants, the high/low-order plant, and the plants with time delays. Such plants are from a wider scope than the theoretical result, and representative of many kinds of the industrial processes. That leads to a new way to simplify the ADRC design via absorbing the engineering experience in designing the PID/PI controller.
Xia, Hong; Luo, Zhendong
2017-01-01
In this study, we devote ourselves to establishing a stabilized mixed finite element (MFE) reduced-order extrapolation (SMFEROE) model holding seldom unknowns for the two-dimensional (2D) unsteady conduction-convection problem via the proper orthogonal decomposition (POD) technique, analyzing the existence and uniqueness and the stability as well as the convergence of the SMFEROE solutions and validating the correctness and dependability of the SMFEROE model by means of numerical simulations.
Rakkiyappan, R; Cao, Jinde; Velmurugan, G
2015-01-01
This paper deals with the problem of existence and uniform stability analysis of fractional-order complex-valued neural networks with constant time delays. Complex-valued recurrent neural networks is an extension of real-valued recurrent neural networks that includes complex-valued states, connection weights, or activation functions. This paper explains sufficient condition for the existence and uniform stability analysis of such networks. Three numerical simulations are delineated to substantiate the effectiveness of the theoretical results.
Chen, Jiyang; Li, Chuandong; Huang, Tingwen; Yang, Xujun
2017-02-01
In this paper, the memristor-based fractional-order neural networks (MFNN) with delay and with two types of stabilizing control are described in detail. Based on the Lyapunov direct method, the theories of set-value maps, differential inclusions and comparison principle, some sufficient conditions and assumptions for global stabilization of this neural network model are established. Finally, two numerical examples are presented to demonstrate the effectiveness and practicability of the obtained results.
Ordinary Workers and Industrial Relations in a New World Order
Nielsen, Niels Jul
2014-01-01
—involving fieldwork at both workplaces and private homes—of Polish migrant laborers participating in the Danish labor market. Firstly, it is shown how the Polish laborers, due to the lower costs they represent, benefit from the new opportunities. Secondly, the paper illustrates how the trade union, though uneasy...... with the downward pressure on wage and working conditions that the Polish represent, prioritizes the organization of workers in order to maintain some degree of control over the labor market. Finally, the question is raised how the EU (European Union) is able to navigate two contrasting concerns: the urge both...
Tawancy, H.M., E-mail: tawancy@kfupm.edu.sa [Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, KFUPM Box 1639, Dhahran 31261 (Saudi Arabia); Aboelfotoh, M.O., E-mail: oaboelfotoh@gmail.com [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27606 (United States)
2014-05-01
We have studied the effect of atom arrangements in the ground state structures of substitutional ordered alloys on their mechanical properties using nickel–molybdenum-based alloys as model systems. Three alloys with nominal compositions of Ni–19.43 at% Mo, Ni–18.53 at% Mo–15.21 at% Cr and Ni–18.72 at% Mo–6.14 at% Nb are included in the study. In agreement with theoretical predictions, the closely related Pt{sub 2}Mo-type, DO{sub 22} and D1{sub a} superlattices with similar energies are identified by electron diffraction of ground state structures, which can directly be derived from the parent disordered fcc structure by minor atom rearrangements on {420}{sub fcc} planes. The three superlattices are observed to coexist during the disorder–order transformation at 700 °C with the most stable superlattice being determined by the exact chemical composition. Although most of the slip systems in the parent disordered fcc structure are suppressed, many of the twinning systems remain operative in the superlattices favoring deformation by twinning, which leads to considerable strengthening while maintaining high ductility levels. Both the Pt{sub 2}Mo-type and DO{sub 22} superlattices are distinguished by high strength and high ductility due to their nanoscale microstructures, which have high thermal stability. However, the D1{sub a} superlattice is found to exhibit poor thermal stability leading to considerable loss of ductility, which has been correlated with self-induced recrystallization by migration of grain boundaries.
Zheng, Mingwen; Li, Lixiang; Peng, Haipeng; Xiao, Jinghua; Yang, Yixian; Zhao, Hui
2016-09-01
In this paper, we study the finite-time stability and synchronization problem of a class of memristor-based fractional-order Cohen-Grossberg neural network (MFCGNN) with the fractional order α ∈ (0,1 ]. We utilize the set-valued map and Filippov differential inclusion to treat MFCGNN because it has discontinuous right-hand sides. By using the definition of Caputo fractional-order derivative, the definitions of finite-time stability and synchronization, Gronwall's inequality and linear feedback controller, two new sufficient conditions are derived to ensure the finite-time stability of our proposed MFCGNN and achieve the finite-time synchronization of drive-response systems which are constituted by MFCGNNs. Finally, two numerical simulations are presented to verify the rightness of our proposed theorems.
Stability of cluster glass state in nano order sized YbFe2O4 powders
Kobayashi, H.; Fujiwara, K.; Kobayashi, N.; Ogawa, T.; Sakai, M.; Tsujimoto, M.; Seri, O.; Mori, S.; Ikeda, N.
2017-04-01
Slow magnetic relaxation and the Fe ion stoichiometry were investigated in spin and charge frustrated system YbFe2O4. DC susceptibility, AC susceptibility, aging process and electron diffraction observation were carried out on nano order sized YbFe2O4 single-phase powders with the Fe/Yb=2.00, 2.02, and 2.04 ratios. The variation of the cluster glass behavior was studied in relation between the magnetic relaxation and the various chemical compositions. With the increase of the Fe/Yb ratios, the magnetic coherence length increased and the magnetic aging time goes slow down. The observed critical slowing down of the glassy fluctuation is interpreted by the development of the spin cluster size. This indicates that the spin glass like property of this material arises from the competition between various sized magnetic domains having ferrimagnetic moments. Additionally, electron diffraction experiments showed that the increase of Fe/Yb ratios from Fe/Yb=2.00 enhances the development of the charge ordering coherence in triangular lattice. This study shows that the measurement of magnetic fluctuation for nano order sized particles gives the essential information about the spin cluster fluctuation in RFe2O4.
PID Controller Stabilization for First-order Integral Processes with Time Delay
无
2006-01-01
Due to the widespread application of the PID controller in industrial control systems, it is desirable to know the complete set of all the stabilizing PID controllers for a given plant before the controller design and tuning. In this paper,the stabilization problems of the classical proportionalintegral-derivative (PID) controller and the singleparameter PID controller (containing only one adjustable parameter) for integral processes with time delay are investigated, respectively. The complete set of stabilizing parameters of the classical PID controller is determined using a version of the Hermite-Biehler Theorem applicable to quasipolynomials. Since the stabilization problem of the single-parameter PID controller cannot be treated by the Hermite-Biehler Theorem, a simple method called duallocus diagram is employed to derive the stabilizing range of the single-parameter PID controller. These results provide insight into the tuning of the PID controllers.
Cross-Order Relations in N=4 Supersymmetric Gauge Theories
Anastasiou, C; Dixon, L J; Kosower, D A
2004-01-01
The anti-de Sitter/conformal field theory duality conjecture raises the question of how the perturbative expansion in the conformal field theory can resum to a simple function. We exhibit a relation between the one-loop and two-loop amplitudes whose generalization to higher-point and higher-loop amplitudes would answer this question. We also provide evidence for the first of these generalizations.
Reformulation of the symmetries of first-order general relativity
Montesinos, Merced; González, Diego; Celada, Mariano; Díaz, Bogar
2017-10-01
We report a new internal gauge symmetry of the n-dimensional Palatini action with cosmological term (n>3 ) that is the generalization of three-dimensional local translations. This symmetry is obtained through the direct application of the converse of Noether’s second theorem on the theory under consideration. We show that diffeomorphisms can be expressed as linear combinations of it and local Lorentz transformations with field-dependent parameters up to terms involving the variational derivatives of the action. As a result, the new internal symmetry together with local Lorentz transformations can be adopted as the fundamental gauge symmetries of general relativity. Although their gauge algebra is open in general, it allows us to recover, without resorting to the equations of motion, the very well-known Lie algebra satisfied by translations and Lorentz transformations in three dimensions. We also report the analog of the new gauge symmetry for the Holst action with cosmological term, finding that it explicitly depends on the Immirzi parameter. The same result concerning its relation to diffeomorphisms and the open character of the gauge algebra also hold in this case. Finally, we consider the non-minimal coupling of a scalar field to gravity in n dimensions and establish that the new gauge symmetry is affected by this matter field. Our results indicate that general relativity in dimension greater than three can be thought of as a gauge theory.
Higher-order factors of the big five and basic values: empirical and theoretical relations.
Vecchione, Michele; Alessandri, Guido; Barbaranelli, Claudio; Caprara, Gianvittorio
2011-08-01
The Big Five Model of personality and Schwartz's theory of basic values are two prominent taxonomies that offer a convenient way to organize the major individual differences in, respectively, personality traits and personal values. Both taxonomies provide a hierarchical framework, whose components can be traced back to a smaller number of broader dimensions. The current study investigated the relationship between the two superordinate factors of personality encompassing the Big Five dimensions (alpha and beta) and the four higher-level value types from Schwartz's theory (Self-transcendence, Self-enhancement, Conservation, and Openness to change). To examine the relations between higher-order traits and values, we relied on factor analysis and multidimensional scaling. Results indicated that alpha and beta were differently related to the Conservation versus Openness to change dimension. Alpha was positively related to values that emphasize protecting stability and respecting norms and traditions, and negatively related to values emphasizing receptiveness to change and independence of thought, feeling, and action. The opposite pattern of relations was found for beta.
Salt marsh stability modelled in relation to sea level rise
Bartholdy, Jesper; Bartholdy, Anders T.; Kroon, Aart
2010-05-01
Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay thickness. Autocompaction was incorporated in the model, and shown to play a major role for the translation of accretion rates measured as length per unit time to accumulation rates measured as mass per area per unit time. This is important, even for shallow salt marsh deposits for which it is demonstrated that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt marsh base. In general, deeper located markers will indicate successively smaller accretion rates with the same sediment input. Thus, stability analysis made on the basis of newly established marker horizons will be biased and indicate salt marsh stabilities far above the correct level. Running the model with a constant sea level revealed that balance between the inner and the outer salt marsh deposition can not be achieved within a reasonable time scale. Likewise it is shown that only one specific sea level rise provides equilibrium for a given location on the salt marsh. With a higher sea level rise, the marsh at the specific location will eventually drown, whereas - with a sea level rise below this level - it will grow towards the top of the rising tidal frame. The short term variation of salt marsh accretion was found to correlate well with variations in the North Atlantic Oscillation - the NAO winter index. Comparisons between the geomorphological development of wind tide affected salt marshes, like those present on the Danish North Sea coasts, and primary astronomically
Stability of auditory event-related potentials in coma research.
Schorr, Barbara; Schlee, Winfried; Arndt, Marion; Lulé, Dorothée; Kolassa, Iris-Tatjana; Lopez-Rolon, Alex; Lopez-Rolon, Alexander; Bender, Andreas
2015-02-01
Patients with unresponsive wakefulness syndrome (UWS) or in minimally conscious state (MCS) after brain injury show significant fluctuations in their behavioural abilities over time. As the importance of event-related potentials (ERPs) in the detection of traces of consciousness increases, we investigated the retest reliability of ERPs with repeated tests at four different time points. Twelve healthy controls and 12 inpatients (8 UWS, 4 MCS; 6 traumatic, 6 non-traumatic) were tested twice a day (morning, afternoon) for 2 days with an auditory oddball task. ERPs were recorded with a 256-channel-EEG system, and correlated with behavioural test scores in the Coma Recovery Scale-revised (CRS-R). The number of identifiable P300 responses varied between zero and four in both groups. Reliabilities varied between Krippendorff's α = 0.43 for within-day comparison, and α = 0.25 for between-day comparison in the patient group. Retest reliability was strong for the CRS-R scores for all comparisons (α = 0.83-0.95). The stability of auditory information processing in patients with disorders of consciousness is the basis for other, even more demanding tasks and cognitive potentials. The relatively low ERP-retest reliability suggests that it is necessary to perform repeated tests, especially when probing for consciousness with ERPs. A single negative ERP test result may be mistaken for proof that a UWS patient truly is unresponsive.
Stoustrup, Jakob; Pommer, Christian; Kliem, Wolfhard
2015-01-01
of the transformation parameters into a new system (I, B 1, C 1) with a symmetrizable matrix C 1. This procedure facilitates stability investigations. We also consider systems with a Hamiltonian spectrum which discloses marginal stability after a Jordan form preserving transformation.......This paper deals with two stability aspects of linear systems of the form Ix¨+Bx˙+Cx=0 given by the triple (I, B, C). A general transformation scheme is given for a structure and Jordan form preserving transformation of the triple. We investigate how a system can be transformed by suitable choices...
Zongyao SUN; Yungang LIU
2007-01-01
In this paper, a new approach is successfully addressed to design the state-feedback adaptive stabilizing control law for a class of high-order nonlinear systems in triangular form and with unknown and nonidentical control coefficients, whose stabilizing control has been investigated recently under the knowledge that the lower bounds of the control coefficients are exactly known. In the present paper,without any knowledge of the lower bounds of the control coefficients, based on the adaptive technique and appropriately choosing design parameters, we give the recursive design procedure of the stabilizing control law by utilizing the approach of adding a power integrator together with tuning functions. The state-feedback adaptive control law designed not only preserves the equilibrium at the origin, but also guarantees the global asymptotic stability of the closed-loop states and the uniform boundedness of all the other closed-loop signals.
2006-01-01
Full Text Available We considered the problem on transversal oscillations of two-layer straight bar, which is under the action of the lengthwise random forces. It is assumed that the layers of the bar were made of nonhomogenous continuously creeping material and the corresponding modulus of elasticity and creeping fractional order derivative of constitutive relation of each layer are continuous functions of the length coordinate and thickness coordinates. Partial fractional differential equation and particular solutions for the case of natural vibrations of the beam of creeping material of a fractional derivative order constitutive relation in the case of the influence of rotation inertia are derived. For the case of natural creeping vibrations, eigenfunction and time function, for different examples of boundary conditions, are determined. By using the derived partial fractional differential equation of the beam vibrations, the almost sure stochastic stability of the beam dynamic shapes, corresponding to the n th shape of the beam elastic form, forced by a bounded axially noise excitation, is investigated. By the use of S. T. Ariaratnam's idea, as well as of the averaging method, the top Lyapunov exponent is evaluated asymptotically when the intensity of excitation process is small.
Low temperature stabilization process for production of carbon fiber having structural order
Rios, Orlando; McGuire, Michael Alan; More, Karren Leslie; Tenhaeff, Wyatt Evan; Menchhofer, Paul A.; Paulauskas, Felix Leonard
2017-08-15
A method for producing a carbon fiber, the method comprising: (i) subjecting a continuous carbon fiber precursor having a polymeric matrix in which strength-enhancing particles are incorporated to a stabilization process during which the carbon fiber precursor is heated to within a temperature range ranging from the glass transition temperature to no less than 20.degree. C. below the glass transition temperature of the polymeric matrix, wherein the maximum temperature employed in the stabilization process is below 400.degree. C., for a processing time within said temperature range of at least 1 hour in the presence of oxygen and in the presence of a magnetic field of at least 1 Tesla, while said carbon fiber precursor is held under an applied axial tension; and (ii) subjecting the stabilized carbon fiber precursor, following step (i), to a carbonization process. The stabilized carbon fiber precursor, resulting carbon fiber, and articles made thereof are also described.
Uniform Stability of a Class of Fractional-Order Nonautonomous Systems with Multiple Time Delays
Tao Zou
2014-01-01
sufficient condition is established for the existence and uniqueness of solutions for such systems involving Caputo fractional derivative, and the uniform stability of solution is studied. At last, two examples are given to demonstrate the applicability of our results.
陈刚; 冯民富; 何银年
2013-01-01
A unified analysis is presented for the stabilized methods including the pres-sure projection method and the pressure gradient local projection method of conforming and nonconforming low-order mixed finite elements for the stationary Navier-Stokes equa-tions. The existence and uniqueness of the solution and the optimal error estimates are proved.
Chu, Chunlei
2009-01-01
We present two Lax‐Wendroff type high‐order time stepping schemes and apply them to solving the 3D elastic wave equation. The proposed schemes have the same format as the Taylor series expansion based schemes, only with modified temporal extrapolation coefficients. We demonstrate by both theoretical analysis and numerical examples that the modified schemes significantly improve the stability conditions.
Uzunov, I. M.; Gölles, M.; Lederer, F.
1995-06-01
We analyze the propagation of soliton trains with small initial separation in the presence of third-order dispersion. We show that both the amplitudes and the positions can be stabilized, provided that phase modulation is applied and adjacent pulses are initially out of phase.
Looft Christian
2011-10-01
Full Text Available Abstract Background Gene expression analysis using real-time RT-PCR (qRT-PCR is increasingly important in biological research due to the high-throughput and accuracy of qRT-PCR. For accurate and reliable gene expression analysis, normalization of gene expression data against housekeeping genes or internal control genes is required. The stability of reference genes has a tremendous effect on the results of relative quantification of gene expression by qRT-PCR. The expression stability of reference genes could vary according to tissues, age of individuals and experimental conditions. In the pig however, very little information is available on the expression stability of reference genes. The aim of this research was therefore to develop a new set of reference genes which can be used for normalization of mRNA expression data of genes expressed in varieties of porcine tissues at different ages. Results The mRNA expression stability of nine commonly used reference genes (B2M, BLM, GAPDH, HPRT1, PPIA, RPL4, SDHA, TBP and YWHAZ was determined in varieties of tissues collected from newborn, young and adult pigs. geNorm, NormFinder and BestKeeper software were used to rank the genes according to their stability. geNorm software revealed that RPL4, PPIA and YWHAZ showed high stability in newborn and adult pigs, while B2M, YWHAZ and SDHA showed high stability in young pigs. In all cases, GAPDH showed the least stability in geNorm. NormFinder revealed that TBP was the most stable gene in newborn and young pigs, while PPIA was most stable in adult pigs. Moreover, geNorm software suggested that the geometric mean of three most stable gene would be the suitable combination for accurate normalization of gene expression study. Conclusions Although, there was discrepancy in the ranking order of reference genes obtained by different analysing software methods, the geometric mean of the RPL4, PPIA and YWHAZ seems to be the most appropriate combination of
Stability of the relative equilibria of a rigid body in a J2 gravity field
Wang, Yue; Xu, Shijie
2014-01-01
The motion of a point mass in the J2 problem is generalized to that of a rigid body in a J2 gravity field. Different with the original J2 problem, the gravitational orbit-rotation coupling of the rigid body is considered in this generalized problem. The linear stability of the classical type of relative equilibria of the rigid body, which have been obtained in our previous paper, is studied in the framework of geometric mechanics with the second-order gravitational potential. Non-canonical Hamiltonian structure of the problem, i.e., Poisson tensor, Casimir functions and equations of motion, are obtained through a Poisson reduction process by means of the symmetry of the problem. The linear system matrix at the relative equilibria is given through the multiplication of the Poisson tensor and Hessian matrix of the variational Lagrangian. Based on the characteristic equation of the linear system matrix, the conditions of linear stability of the relative equilibria are obtained. With the stability conditions obta...
周学华; 李津如; 刘春艳; 江龙
2002-01-01
Gold nanoparticles modified with C10NH2, C12NH2, C16NH2 and C18NH2 respectively have been prepared by the reverse micelle method. Nanoparticles stability and their two-dimensional (2D) ordered arrangement were studied by UV-Vis absorption spectra and LB technique. The factors, such as the chain length and the size distribution of particles, which affect the 2D ordered arrangement formation, are discussed. Experimental results show that the longer the chain length of surfactants capping the gold nanoparticles, the more stable the nanoparticles, and the more ordered 2D arrangement of gold nanoparticles.
Gao, Fangzheng; Wu, Yuqiang
2015-03-01
This paper considers the problem of global stabilization by state feedback for a class of high-order nonlinear systems with time-varying delays. Comparing with the existing relevant literature, the systems under investigation allow more uncertainties, to which the existing control methods are inapplicable. By introducing sign function and necessarily modifying the method of adding a power integrator, a state feedback controller is successfully constructed to preserve the equilibrium at the origin and guarantee the global asymptotic stability of the resulting closed-loop system. Finally, two simulation examples are provided to illustrate the effectiveness of the proposed approach.
Fuhrmann, David R.; Bingham, Harry B.; Madsen, Per A.
2004-01-01
This paper considers a method of lines stability analysis for finite difference discretizations of a recently published Boussinesq method for the study of highly nonlinear and extremely dispersive water waves. The analysis demonstrates the near-equivalence of classical linear Fourier (von Neumann...
Fuhrman, David R.; Bingham, Harry B.; Madsen, Per A.;
2004-01-01
This paper considers a method of lines stability analysis for finite difference discretizations of a recently published Boussinesq method for the study of highly non-linear and extremely dispersive water waves. The analysis demonstrates the near-equivalence of classical linear Fourier (von Neumann......) techniques with matrix-based methods for formulations in both one and two horizontal dimensions. The matrix-based method is also extended to show the local de-stabilizing effects of the non-linear terms, as well as the stabilizing effects of numerical dissipation. A comparison of the relative stability...... moderately non-normal, suggesting that the eigenvalues are likely suitable for analysis purposes. Numerical experiments demonstrate excellent agreement with the linear analysis, and good qualitative agreement with the local non-linear analysis. The various methods of analysis combine to provide significant...
Sun, Yuxin; Xiong, Zhenhua
2017-01-01
In turning processes, chatter is an unstable vibration which adversely affects surface finish and machine tool components. Stiffness variation (SV) is an effective strategy for chatter suppression by periodically modulating the stiffness around a nominal value. The dynamics of SV turning is governed by a time periodic delay differential equation (DDE) where the time-period/time-delay ratio (TPTDR) can be arbitrary. Recently, first-, second- and higher-order full-discretization methods (FDMs) have been reported as a popular class of methods for milling stability prediction. However, these FDMs can only deal with time periodic DDE where the TPTDR equals one. In this paper, two high-order FDMs using Lagrange interpolation (HLFDMs) are proposed for stability analysis of SV turning. On each discrete time interval, the time delay term is interpolated by the second-degree Lagrange polynomial, and the time periodic term is linearly interpolated. The state term is approximated using linear interpolation and second-degree Lagrange polynomial interpolation, achieving the first- and second-order HLFDM, respectively. Finally, the transition matrix over a single period is deduced for stability analysis via the Floquet theory. Benchmark examples of damped delay Mathieu equations are used to verify the proposed algorithm, which demonstrates that HLFDMs are highly efficient and accurate. In addition, the second-order HLFDM is used to investigate the effects of SV amplitude and frequency parameters. These results provide theoretical insights for the selection of SV parameters.
Stability of equilibrium under constraints: Role of second-order constrained derivatives
Gal, Tamas
2007-01-01
In the stability analysis of an equilibrium, given by a stationary point of a functional F[n] (free energy functional, e.g.), the second derivative of F[n] plays the essential role. If the system in equilibrium is subject to the conservation constraint of some extensive property (e.g. volume, material, or energy conservation), the Euler equation determining the stationary point corresponding to the equilibrium alters according to the method of Lagrange multipliers. Here, the question as to ho...
Structural Stabilities of Ordered Nb4 Clusters on the Cu(111) and Cu(100) Surfaces
WANG Xiao-Chun; ZHU Zi-Zhong
2007-01-01
@@ Based on first-principles calculations, we show that very high-density periodic arrays of Nb4 clusters with both the tetrahedron and quadrangle configurations can be stably absorbed on the Cu(111) and Cu(100) surfaces,with the quadrangle configurations more stable than the tetrahedron ones. The strong covalent bonding between atoms within the Nb4 clusters contributes to the stability of Nb4 adsorptions on the Cu surfaces.
Huang, Rao; Shao, Gui-Fang; Zhang, Yang; Wen, Yu-Hua
2017-04-12
Pt-Co bimetallic nanoparticles are promising candidates for Pt-based nanocatalysts and magnetic-storage materials. By using molecular dynamics simulations, we here present a detailed examination on the thermal stabilities of Pt-Co bimetallic nanoparticles with three configurations including chemically disordered alloy, ordered intermetallics, and core-shell structures. It has been revealed that ordered intermetallic nanoparticles possess better structural and thermal stability than disordered alloyed ones for both Pt3Co and PtCo systems, and Pt3Co-Pt core-shell nanoparticles exhibit the highest melting points and the best thermal stability among Pt-Co bimetallic nanoparticles, although their meltings all initiate at the surface and evolve inward with increasing temperatures. In contrast, Co-Pt core-shell nanoparticles display the worst thermal stability compared with the aforementioned nanoparticles. Furthermore, their melting initiates in the core and extends outward surface, showing a typical two-stage melting mode. The solid-solid phase transition is discovered in Co core before its melting. This work demonstrates the importance of composition distribution to tuning the properties of binary nanoparticles.
Related Studies in Long Term Lithium Battery Stability
Horning, R. J.; Chua, D. L.
1984-01-01
The continuing growth of the use of lithium electrochemical systems in a wide variety of both military and industrial applications is primarily a result of the significant benefits associated with the technology such as high energy density, wide temperature operation and long term stability. The stability or long term storage capability of a battery is a function of several factors, each important to the overall storage life and, therefore, each potentially a problem area if not addressed during the design, development and evaluation phases of the product cycle. Design (e.g., reserve vs active), inherent material thermal stability, material compatibility and self-discharge characteristics are examples of factors key to the storability of a power source.
Age-related declines of stability in visual perceptual learning.
Chang, Li-Hung; Shibata, Kazuhisa; Andersen, George J; Sasaki, Yuka; Watanabe, Takeo
2014-12-15
One of the biggest questions in learning is how a system can resolve the plasticity and stability dilemma. Specifically, the learning system needs to have not only a high capability of learning new items (plasticity) but also a high stability to retain important items or processing in the system by preventing unimportant or irrelevant information from being learned. This dilemma should hold true for visual perceptual learning (VPL), which is defined as a long-term increase in performance on a visual task as a result of visual experience. Although it is well known that aging influences learning, the effect of aging on the stability and plasticity of the visual system is unclear. To address the question, we asked older and younger adults to perform a task while a task-irrelevant feature was merely exposed. We found that older individuals learned the task-irrelevant features that younger individuals did not learn, both the features that were sufficiently strong for younger individuals to suppress and the features that were too weak for younger individuals to learn. At the same time, there was no plasticity reduction in older individuals within the task tested. These results suggest that the older visual system is less stable to unimportant information than the younger visual system. A learning problem with older individuals may be due to a decrease in stability rather than a decrease in plasticity, at least in VPL. Copyright © 2014 Elsevier Ltd. All rights reserved.
Wind turbine power and sound in relation to atmospheric stability
van den Berg, G. P.
2008-01-01
Atmospheric stability cannot, with respect to modem, toll wind turbines, be viewed as a 'small perturbation to a basic neutral state' This can be demonstrated by comparison of measured wind velocity at the height of the rotor with the wind velocity expected in a neutral or 'standard' atmosphere.
Age-Related Differences in Evaluating Developmental Stability
Mustafic, Maida; Freund, Alexandra M.
2013-01-01
Two studies examined the hypothesis that the evaluation of developmental stability changes across adulthood. Results of Study 1 ("N" = 119) supported the expectation that older adults ("M"[subscript age] = 65.29 years)--compared to younger ("M"[subscript age] = 23.38 years) and middle-aged adults…
Wind turbine power and sound in relation to atmospheric stability
van den Berg, G. P.
2008-01-01
Atmospheric stability cannot, with respect to modem, toll wind turbines, be viewed as a 'small perturbation to a basic neutral state' This can be demonstrated by comparison of measured wind velocity at the height of the rotor with the wind velocity expected in a neutral or 'standard' atmosphere. Atm
Mother-Adolescent Conflict: Stability, Change, and Relations with Externalizing
Hofer, Claire; Eisenberg, Nancy; Spinrad, Tracy L.; Morris, Amanda S.; Gershoff, Elizabeth; Valiente, Carlos; Kupfer, Anne; Eggum, Natalie D.
2013-01-01
Stability and change in mother-adolescent conflict reactions (CRs) and the prediction of CRs from adolescents' earlier behavior problems (and vice versa) were examined with 131 mothers and their adolescents (63 boys). Dyads engaged in a 6-min conflict discussion twice, 2 years apart ["M" age was 13 at Time 1 (T1)]. Non-verbal expressive…
Rudolf Hoermann
2016-11-01
Full Text Available Thyroid hormone concentrations only become sufficient to maintain a euthyroid state through appropriate stimulation by pituitary TSH. In such a dynamic system under constant high pressure, guarding against overstimulation becomes vital. Therefore, several defensive mechanisms protect against accidental overstimulation, such as plasma protein binding, conversion of T4 into the more active T3, active transmembrane transport, counter-regulatory activities of reverse T3 and thyronamines and negative hypothalamic-pituitary-thyroid feedback control of TSH. TSH has gained a dominant but misguided role in interpreting thyroid function testing in assuming that its exceptional sensitivity thereby translates into superior diagnostic performance. However, TSH-dependent thyroid disease classification is heavily influenced by statistical analytic techniques such as uni- or multivariate-defined normality. This demands a separation of its conjoint roles as a sensitive screening test and accurate diagnostic tool. Homeostatic equilibria (set points in healthy subjects are less variable, and do not follow a pattern of random variation, rather indicating signs of early and progressive homeostatic control across the euthyroid range. In the event of imminent thyroid failure with a reduced FT4 output per unit TSH, conversion efficiency increases in order to maintain FT3 stability. In such situations, T3 stability takes priority over set point maintenance. This suggests a concept of relational stability. These findings have important implications for both TSH reference limits and treatment targets for patients on levothyroxine. The use of archival markers is proposed to facilitate the homeostatic interpretation of all parameters.
Lagrangian relative equilibria for a gyrostat in the three-body problem: bifurcations and stability
Guirao, Juan L G; Vera, Juan A, E-mail: juan.garcia@upct.e, E-mail: juanantonio.vera@upct.e [Departamento de Matematica Aplicada y EstadIstica, Universidad Politecnica de Cartagena, Hospital de Marina, 30203 Cartagena, Region de Murcia (Spain)
2010-05-14
In this paper we consider the non-canonical Hamiltonian dynamics of a gyrostat in the frame of the three-body problem. Using geometric/mechanic methods we study the approximate dynamics of the truncated Legendre series representation of the potential of an arbitrary order. Working in the reduced problem, we study the existence of relative equilibria that we refer to as Lagrange type following the analogy with the standard techniques. We provide necessary and sufficient conditions for the linear stability of Lagrangian relative equilibria if the gyrostat morphology form is close to a sphere. Thus, we generalize the classical results on equilibria of the three-body problem and many results on them obtained by the classic approach for the case of rigid bodies.
Monotone Regression and Correction for Order Relation Deviations in Indicator Kriging
Han Yan; Yang Yiheng
2008-01-01
The indicator kriging (IK) is one of the most efficient nonparametric methods in geo-statistics. The order relation problem in the conditional cumulative distribution values obtained by IK is the most severe drawback of it. The correction of order relation deviations is an essential and important part of IK approach. A monotone regression was proposed as a new correction method which could minimize the deviation from original quintiles value, although, ensuring all order relations.
Influence of higher order modes on the beam stability in the high power superconducting proton linac
Schuh, M; Gerigk, F; Tuckmantel, J
2011-01-01
Higher order modes (HOMs) can severely limit the operation of superconducting cavities in a linear accelerator with high beam current, high duty factor, and complex pulse structure. The full HOM spectrum has to be analyzed in order to identify potentially dangerous modes already during the design phase and to define their damping requirements. For this purpose a dedicated beam simulation code simulation of higher order mode dynamics (SMD) focused on beam-HOM interaction was developed, taking into account important effects like the HOM frequency spread, beam input jitter, different chopping patterns, as well as klystron and alignment errors. Here, SMD is used to investigate the influence of HOMs in detail in the superconducting proton linac at CERN and their potential to drive beam instabilities in the longitudinal and transverse plane.
Influence of higher order modes on the beam stability in the high power superconducting proton linac
Marcel Schuh
2011-05-01
Full Text Available Higher order modes (HOMs can severely limit the operation of superconducting cavities in a linear accelerator with high beam current, high duty factor, and complex pulse structure. The full HOM spectrum has to be analyzed in order to identify potentially dangerous modes already during the design phase and to define their damping requirements. For this purpose a dedicated beam simulation code simulation of higher order mode dynamics (SMD focused on beam-HOM interaction was developed, taking into account important effects like the HOM frequency spread, beam input jitter, different chopping patterns, as well as klystron and alignment errors. Here, SMD is used to investigate the influence of HOMs in detail in the superconducting proton linac at CERN and their potential to drive beam instabilities in the longitudinal and transverse plane.
Stability predictions for high-order ΣΔ modulators based on quasilinear modeling
Risbo, Lars
1994-01-01
This paper introduces a novel interpretation of the instability mechanisms in high-order one-bit Sigma-Delta modulators. Furthermore, it is demonstrated how the maximum stable amplitude range can be predicted very well. The results are obtained using an extension of the well known quasilinear mod...... modeling of the one-bit quantizer. The theoretical results are verified by numerical simulations of a number of realistic 4th order modulators designed by means of standard filter design tools. The results are useful for automated design and optimization of loop filters...
On Relative Stabilities of Distinct Polyenes. An Extension of the Concept of Conjugated Paths
Gineityte, Viktorija
2015-01-01
The study continues the previous development [MATCH, 72 (2014) 39-73] of the perturbative approach to relative stabilities of pi-electron systems of conjugated hydrocarbons modeled as sets of weakly-interacting initially-double (C=C) bonds. Distinct isomers of acyclic hydrocarbons (polyenes) are now under focus. The relevant total pi-electron energies (E) are expressed in the form of power series containing members (E_(k)) of even orders (k=0,2,4,...) with respect to the averaged resonance parameter of initially-single (C-C) bonds. Terms to within the sixth order (k=6) inclusive are shown to be of importance for discrimination between similar isomers. In this connection, missing expressions for corrections E_(6) are originally derived. Conjugated paths of various lengths (i.e. linear chains consisting of C=C and C-C bonds alternately) are shown to be the most important (but not the only) fragments contributing to stabilization of any acyclic pi-electron system. Again, new types of fragments (substructures) ar...
A STABILITY RESULT ON SOLUTIONS TO CERTAIN FOURTH ORDER NON-HOMOGENEOUS DIFFERENTIAL EQUATIONS
A.M.A.; Abou-El-Ela; A.I.; Sadek; E.S.; Farghaly
2009-01-01
In this paper,we study the fourth order non-homogeneous differential equations x(4) + f1()+ f2() + f3(■) + f4(x) = p(t,x,■,,x),and obtain suffcient conditions,under which the solutions to the system tend to zero as t →∞.
A STABILITY RESULT ON SOLUTIONS TO CERTAIN FOURTH ORDER NON-HOMOGENEOUS DIFFERENTIAL EQUATIONS
A.M.A.Abou-El-Ela; A.I.Sadek; E.S.Farghaly
2009-01-01
In this paper,we study the fourth order non-homogeneous differential equations x(4)+f1(x)x+f2(x)+f3(x)+f4 (x)= p(t,x,x,x,x),and obtain sufficient conditions,under which the solutions to the system tend to zero as t→∞.
Short-range order types in binary alloys: A reflection of coherent phase stability
W. Wolverton; V. Ozolins; Alex Zunger
1999-11-23
The short-range order (SRO) present in disordered solid solutions is classified according to three characteristic system-dependent energies: (1) formation enthalpies of ordered compounds, (2) enthalpies of mixing of disordered alloys, and (3) the energy of coherent phase separation, (the composition-weighted energy of the constituents each constrained to maintain a common lattice constant along an A/B interface). These energies are all compared against a common reference, the energy of incoherent phase separation (the composition-weighted energy of the constituents each at their own equilibrium volumes). Unlike long-range order (LRO), short-range order is determined by energetic competition between phases at a fixed composition, and hence only coherent phase-separated states are of relevance for SRO. The authors find five distinct SRO types, and show examples of each of these five types, including Cu-Au, Al-Mg, GaP-InP, Ni-Au, and Cu-Ag. The SRO is calculated from first-principles using the mixed-space cluster expansion approach combined with Monte Carlo simulations. Additionally, they examine the effect of inclusion of coherency strain in the calculation of SRO, and specifically examine the appropriate functional form for accurate SRO calculations.
Ligmann-Zielinska, Arika; Jankowski, Piotr
2012-04-01
This paper presents a new approach to deriving preferences assigned to evaluation criteria in geographical multicriteria decision analysis. In this approach, the preferences, expressed by numeric weights, are adjusted by distance measures derived from the explicit consideration of a locational structure. The structure is given by locations of decision options and high importance reference objects. The approach is demonstrated on the example of a house selection case study in San Diego, California. The results show that proximity-adjusted preferences for the evaluation criteria can alter significantly the rank order of decision options. Consequently, the explicit modeling of spatial preference variability may be needed in order to better account for decision-maker's preferences.
44 CFR 402.6 - Relation to Transportation Order T-2.
2010-10-01
... Order T-2. 402.6 Section 402.6 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.6 Relation to Transportation Order T-2. Transportation Order T-1 applies to the transportation of commodities to, or in transit...
Nada S. Abdelwahab
2017-05-01
Full Text Available The present work concerns with the development of stability indicating the RP-HPLC method for simultaneous determination of guaifenesin (GUF and pseudoephedrine hydrochloride (PSH in the presence of guaifenesin related substance (Guaiacol. GUC, and in the presence of syrup excepients with minimum sample pre-treatment. In the developed RP-HPLC method efficient chromatographic separation was achieved for GUF, PSH, GUC and syrup excepients using ODS column as a stationary phase and methanol: water (50:50, v/v, pH = 4 with orthophosphoric acid as a mobile phase with a flow rate of 1 mL min−1 and UV detection at 210 nm. The chromatographic run time was approximately 10 min. Calibration curves were drawn relating the integrated area under peak to the corresponding concentrations of PSH, GUF and GUC in the range of 1–8, 1–20, 0.4–8 μg mL−1, respectively. The developed method has been validated and met the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated method was successfully applied for determination of the studied drugs in triaminic chest congestion® syrup; moreover its results were statistically compared with those obtained by the official method and no significant difference was found between them.
Preparation and structural stability of ordered nanocomposites: opal matrix - lead titanates
Samoylovich, M. I.; Mkrtchyan, A. R.; Belyanin, A. F.; Bagdasaryan, S. A.; Kiziridi, A. A.
2016-06-01
The conditions for the formation of nanocomposites based on the basis of lattice packings of SiO2 nanospheres (opal matrices) with included crystallites of lead titanates (PbTiO3 and PbTi3O7) in interspherical nanospacing are considered. For the formation of nanocomposites are used sample opal matrices with dimensions of single-domain regions ≥0,1 mm.3 The diameter of SiO2 nanospheres was ∼260 nm. Obtained nanocomposites volume >2 cm3 in filling >20% of interspherical nanospacing PbTiO3, PbTi3O7 crystallites were size of 16-36 nm. Using X-ray diffraction and Raman spectroscopy are studied composition and structural stability when heated nanocomposites to 550°C, which allowed the identification of a local phase transition with change of the space group. The dependence of the composition of synthesized materials on the conditions of their preparation is submitted.
The Orbital Stability of Planets Trapped in the First-Order Mean-Motion Resonances
Matsumoto, Yuji; Ida, Shigeru
2012-01-01
Many extrasolar planetary systems containing multiple super-Earths have been discovered. N-body simulations taking into account standard type-I planetary migration suggest that protoplanets are captured into mean-motion resonant orbits near the inner disk edge at which the migration is halted. Previous N-body simulations suggested that orbital stability of the resonant systems depends on number of the captured planets. In the unstable case, through close scattering and merging between planets, non-resonant multiple systems are finally formed. In this paper, we investigate the critical number of the resonantly trapped planets beyond which orbital instability occurs after disk gas depletion. We find that when the total number of planets ($N$) is larger than the critical number ($N_{\\rm crit}$), crossing time that is a timescale of initiation of the orbital instability is similar to non-resonant cases, while the orbital instability never occurs within the orbital calculation time ($10^8$ Kepler time) for $N\\leq ...
Relative oxidative stability of diacylglycerol and triacylglycerol oils.
Qi, Jin F; Wang, Xiang Y; Shin, Jung-Ah; Lee, Young-Hwa; Jang, Young-Seok; Lee, Jeung Hee; Hong, Soon-Taek; Lee, Ki-Teak
2015-03-01
To compare the oxidative stability between diacylglycerol (DAG) oil and conventional triacylglycerol (TAG) oil (that is, soybean oil), the prepared stripped diacylglycerol oil (SDO) and soybean oil (SSBO) were stored at 60 °C in the dark for 144 h. During storage peroxide values (POVs), contents of aldehydes, unsaturated fatty acids were measured to evaluate the oxidative stabilities of the 2 oils. The results showed the content of C18:2, C18:3, and total unsaturated fatty acid decreased faster in DAG oil than in soybean oil, whereas the decreased rate of C18:1 was similar in 2 oils. Also, both rate constants (K1 and K2) obtained from POV (K1 ) and total aldehydes (K2 ) indicated that DAG oil (K1 = 3.22 mmol/mol FA h(-1) , K2 = 0.023 h(-1)) was oxidized more rapidly than soybean oil (K1 = 2.56 mmol/mol FA h(-1) , K2 = 0.021 h(-1)), which was mainly due to the difference of acylglycerol composition of the 2 oils along with higher C18:3 (9.6%) in SDO than SSBO (5.7%). It is concluded that DAG was more easily oxidized than soybean oil at 60 °C in the dark for 144 h.
Moral Judgment and Its Relation to Second-Order Theory of Mind
Fu, Genyue; Xiao, Wen S.; Killen, Melanie; Lee, Kang
2014-01-01
Recent research indicates that moral judgment and 1st-order theory of mind abilities are related. What is not known, however, is how 2nd-order theory of mind is related to moral judgment. In the present study, we extended previous findings by administering a morally relevant theory of mind task (an accidental transgressor) to 4- to 7-year-old…
Moral Judgment and Its Relation to Second-Order Theory of Mind
Fu, Genyue; Xiao, Wen S.; Killen, Melanie; Lee, Kang
2014-01-01
Recent research indicates that moral judgment and 1st-order theory of mind abilities are related. What is not known, however, is how 2nd-order theory of mind is related to moral judgment. In the present study, we extended previous findings by administering a morally relevant theory of mind task (an accidental transgressor) to 4- to 7-year-old…
Model Order Reductions for Stability Analysis of Islanded Microgrids With Droop Control
Mariani, Valerio; Vasca, Francesco; Vásquez, Juan C.;
2015-01-01
Three-phase inverters subject to droop control are widely used in islanded microgrids to interface distributed energy resources to the network and to properly share the loads among different units. In this paper, a mathematical model for islanded microgrids with linear loads and inverters under...... frequency and voltage droop control is proposed. The model is constructed by introducing a suitable state space transformation which allows to write the closed loop model in an explicit state space form. Then, the singular perturbations technique is used to obtain reduced order models which reproduce...
Stabilization of Néel order in frustrated magnets with increasing magnetic field
Schmidt, Burkhard; Siahatgar, Mohammad; Thalmeier, Peter
2013-01-01
For low-dimensional frustrated quantum magnets, the dependence of the staggered moment ms on a magnetic field is nonmonotonic: For small and intermediate fields, quantum fluctuations are gradually suppressed, leading to an increase of ms (H). For large applied magnetic fields however, the classically expected monotonous decrease is recovered. For the same reasons, the Néel ordering temperature TN of such compounds first increases and then exhibits a reentrant behavior as a function of the field strength. The quantitative analysis of this behavior is an excellent tool to determine the frustration parameter of a given compound. We have derived a general linear spin-wave (LSW) theory in the presence of a magnetic field. Based on our LSW theory, including a small interlayer coupling, we use a self-consistent approach determining TN by the condition of a vanishing total moment. We apply our findings to the recently measured field dependence of the magnetic ordering temperature TN of Cu(pz)2 (ClO4)2 in the framework of the S = 1/2 two-dimensional J1-J2 Heisenberg model. The observed increase with increasing field strength can be understood naturally using an intermediate frustration ratio J2/J1 ≈ 0.2, which is in accordance with the field dependence of the staggered moment.
LDA+DMFT approach to ordering phenomena and the structural stability of correlated materials
Kuneš, J.; Leonov, I.; Augustinský, P.; Křápek, V.; Kollar, M.; Vollhardt, D.
2017-07-01
Materials with correlated electrons often respond very strongly to external or internal influences, leading to instabilities and states of matter with broken symmetry. This behavior can be studied theoretically either by evaluating the linear response characteristics, or by simulating the ordered phases of the materials under investigation. We developed the necessary tools within the dynamical mean-field theory (DMFT) to search for electronic instabilities in materials close to spin-state crossovers and to analyze the properties of the corresponding ordered states. This investigation, motivated by the physics of LaCoO3, led to a discovery of condensation of spinful excitons in the two-orbital Hubbard model with a surprisingly rich phase diagram. The results are reviewed in the first part of the article. Electronic correlations can also be the driving force behind structural transformations of materials. To be able to investigate correlation-induced phase instabilities we developed and implemented a formalism for the computation of total energies and forces within a fully charge self-consistent combination of density functional theory and DMFT. Applications of this scheme to the study of structural instabilities of selected correlated electron materials such as Fe and FeSe are reviewed in the second part of the paper.
Stability Analysis for Travelling Wave Solutions of the Olver and Fifth-Order KdV Equations
A. R. Seadawy
2014-01-01
Full Text Available The Olver equation is governing a unidirectional model for describing long and small amplitude waves in shallow water waves. The solitary wave solutions of the Olver and fifth-order KdV equations can be obtained by using extended tanh and sech-tanh methods. The present results are describing the generation and evolution of such waves, their interactions, and their stability. Moreover, the methods can be applied to a wide class of nonlinear evolution equations. All solutions are exact and stable and have applications in physics.
Shi, L; Jones., R M
2014-01-01
erating cavities at FLASH linac, DESY, are equipped with electronics for beam position monitoring, which are based on HOM signals from special couplers. These monitors provide the beam position without additional vacuum components and at low cost. Moreover, they can be used to align the beam in the cavities to reduce the HOM effects on the beam. However, the HOMBPM (Higher Order Mode based Beam Position Monitor) shows an instability problem over time. In this paper, we will present the status of studies on this issue. Several methods are utilized to calibrate the HOMBPMs. These methods include DLR (Direct Linear Regression), and SVD (Singular Value Decomposition). We found that SVD generally is more suitable for HOMBPM calibration. We focus on the HOMBPMs at 1.3 GHz cavities. Techniques developed here are applicable to 3.9 ...
Structural Stabilities of Ordered Arrays of Nb4 Clusters on NaCl(100) Surface
WANG Xiao-Chun; ZHANG Jian-Hua; WEN Yu-Hua; ZHU Zi-Zhong
2009-01-01
Adsorption of ordered (2 × 2) arrays of Nb4 clusters on the insulating surface of NaCl(100) is studied by the first-principles calculations within the density functional theory. The calculations on the relaxed geometries and cohesive energies show that both the tetrahedron and quadrangle-Nb4 can be stably adsorbed on this substrate, which may have important applications. The adsorption of quadrangle-Nb4 on the NaCl(100) surface is more stable than that of tetrahedron-Nb4. Both the Nb4 clusters studied and a single Nb atom prefer the top site of the Cl atom in the NaCl(100) surface. Electronic structure analysis suggests that the interactions between the Nb4 dusters and the substrate are weak.
First-order D-type Iterative Learning Control for Nonlinear Systems with Unknown Relative Degree
SONGZhao-Qing; MAOJian-Qin; DAIShao-Wu
2005-01-01
The classical D-type iterative learning control law depends crucially on the relative degree of the controlled system, high order differential iterative learning law must be taken for systems with high order relative degree. It is very difficult to ascertain the relative degree of the controlled system for uncertain nonlinear systems. A first-order D-type iterative learning control design method is presented for a class of nonlinear systems with unknown relative degree based on dummy model in this paper. A dummy model with relative degree 1 is constructed for a class of nonlinear systems with unknown relative degree. A first-order D-type iterative learning control law is designed based on the dummy model, so that the dummy model can track the desired trajectory perfectly, and the controlled system can track the desired trajectory within a certain error. The simulation example demonstrates the feasibility and effectiveness of the presented method.
Cordier, Laurent; Tissot, Gilles; Noack, Bernd
2014-11-01
The aim of this communication is to demonstrate the use of Reduced-Order Model (ROM) based on Proper Orthogonal Decomposition (POD) to stabilize the flow over a circular cylinder in the laminar regime (Reynolds number equal to 60). The control is introduced by vertical oscillations of the cylinder, the objective being to determine by linear control the vertical velocity of the cylinder that stabilizes the flow. Since in Fluid-Structure Interaction, the POD algorithm cannot be applied directly, the fictitious domain method of Glowinski et al. (JMF 1999) is implemented where the solid domain is treated as a fluid undergoing an additional constraint. The POD-ROM is then classically obtained by projecting the Navier-Stokes equations on the first POD modes. The cylinder movement is enforced in the POD-ROM through the introduction of Lagrange multipliers. Finally, a Linear Quadratic Regulator framework is used to determine the optimal control law such that the flow is stabilized. Partially funded by the ANR Chair of Excellence TUCOROM and the Carnot project INTACOO.
Optical relative calibration and stability monitoring for the Auger fluorescence detector
Aramo, Carla; Brack, J.; Caruso, R.; D' Urso, D.; Fazio, D.; Fonte, R.; Gemmeke, H.; Kleifges, M.; Knapik, R.; Insolia, A.; /Catania U.; Matthews, J.A.J.; Menshikov, A.; Miller, W.; Privitera, P.; Rodriguez Martino, J.
2005-07-01
The stability of the fluorescence telescopes of the Pierre Auger Observatory is monitored with the optical relative calibration setup. Optical fibers distribute light pulses to three different diffuser groups within the optical system. The total charge per pulse is measured for each pixel and compared with reference calibration measurements. This allows monitoring the short and long term stability with respect of the relative timing between pixels and the relative gain for each pixel. The designs of the LED calibration unit (LCU) and of the Xenon flash lamp used for relative calibration, are described and their capabilities to monitor the stability of the telescope performances are studied. We report the analysis of relative calibration data recorded during 2004. Fluctuations in the relative calibration constants provide a measure of the stability of the FD.
Gogoi, R; Kalita, L; Devi, N, E-mail: runmoni_gogoi@rediffmail.co, E-mail: latikakalita@rediffmail.co, E-mail: nirupama_cotton@rediffmail.co [Department of Mathematics, Cotton College, Guwahati-781001, Assam (India)
2010-02-01
Much interest was shown towards the studies on nonlinear stability in the late sixties. Plasma instabilities play an important role in plasma dynamics. More attention has been given towards stability analysis after recognizing that they are one of the principal obstacles in the way of a successful resolution of the problem of controlled thermonuclear fusion. Nonlinearity and dispersion are the two important characteristics of plasma instabilities. Instabilities and nonlinearity are the two important and interrelated terms. In our present work, the continuity and momentum equations for both ions and electrons together with the Poisson equation are considered as cold plasma model. Then we have adopted the modified reductive perturbation technique (MRPT) from Demiray [1] to derive the higher order equation of the Nonlinear Schroedinger equation (NLSE). In this work, detailed mathematical expressions and calculations are done to investigate the changing character of the modulation of ion acoustic plasma wave through our derived equation. Thus we have extended the application of MRPT to derive the higher order equation. Both progressive wave solutions as well as steady state solutions are derived and they are plotted for different plasma parameters to observe dark/bright solitons. Interesting structures are found to exist for different plasma parameters.
C A Igwe; M Zarei; K Stahr
2013-10-01
The stability of some highly weathered soils of the tropics is controlled by their organo-mineral substances. Highly weathered soils from 10 different locations were sampled from their A and B horizons to determine their aggregate stability. The objective of the study was to determine the aggregate stability of the soils and their relationships with geochemical constituents. The major geochemical elements of the soils are quartz and kaolinite, SiO2, Al2O3 and Fe2O3, while the dithionite extractable Fe and Al was greater than their corresponding oxalate and pyrophosphate forms. The mean-weight diameter from dried aggregates (MWDd) and their corresponding wet mean-weight diameter (MWDw) were related significantly (r = 0.64*). The dithionite extracted Al and Fe or the crystalline forms of these elements were outstanding in the stability of the aggregates. However, this did not diminish the influence of SOC reduced to third order level in the stability of the soils. The influence of SOC in these soils, however, indirectly manifested on the role of Fep and Alp in the aggregation of these soils. The crystalline Fe and Al sesquioxides were very prominent in the aggregation and stability of these soils.
Structures and related properties of helical, disulfide-stabilized peptides
Pagel, M.D. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States)
1993-11-01
The three dimensional structure of several peptides were determined by NMR spectroscopy and distance geometry calculations. Each peptide formed a predictable, rigid structure, consisting of an {alpha}-helix, a {open_quotes}scaffold{close_quotes} region which packed along one face of the helix, and two disulfide bridges which covalently connect the helix and scaffold regions. The peptide Apa-M5 was designed to constrain the M5 peptide from MLCK in a helical geometry using the apamin disulfide scaffold. This scaffold constrains the N- terminal end of the helix with two disulfide bridges and a reverse turn. Like the M5 peptide, Apa-M5 was found to bind calmodulin in a Ca{sup 2+}-dependent 1:1 stoichiometry. However, the dissociation constant of the (Apa-M5)-calmodulin complex, 107 nM, was 100-fold higher than the dissociation constant of the M5-calmodulin complex. This difference was due to a putative steric overlap between the Apa-M5 scaffold and calmodulin. The peptide Apa-Cro was designed to replace the large structural protein matrix of {lambda} Cro with the apamin disulfide scaffold. However, Apa-Cro did not bind the consensus DNA operator half-site of {lambda} Cro, probably due to a steric overlap between the Apa-Cro disulfide framework and the DNA. The amino acid sequence of the scaffold-disulfide bridge arrangement of the peptide Max was derived from the core sequence of scyllatoxin, which contains an {alpha}-helix constrained at the C-terminal end by two disulfide bridges and a two-stranded {beta}sheet scaffold. Max was shown to fold with >84% yield to form a predictable, stable structure that is similar to scyllatoxin. The folding and stability properties of Max make this scaffold and disulfide bridge arrangement an ideal candidate for the development of hybrid sequence peptides. The dynamics of a fraying C-terminal end of the helix of the peptide Apa-AlaN was determined by analysis of {sup 15}N NMR relaxation properties.
Structures and related properties of helical, disulfide-stabilized peptides
Pagel, Mark D. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
1993-11-01
The three dimensional structure of several peptides were determined by NMR spectroscopy and distance geometry calculations. Each peptide formed a predictable, rigid structure, consisting of an α-helix, a "scaffold" region which packed along one face of the helix, and two disulfide bridges which covalently connect the helix and scaffold regions. The peptide Apa-M5 was designed to constrain the M5 peptide from MLCK in a helical geometry using the apamin disulfide scaffold. This scaffold constrains the N- terminal end of the helix with two disulfide bridges and a reverse turn. Like the M5 peptide, Apa-M5 was found to bind calmodulin in a Ca^{2+}-dependent 1:1 stoichiometry. However, the dissociation constant of the (Apa-M5)-calmodulin complex, 107 nM, was 100-fold higher than the dissociation constant of the M5-calmodulin complex. This difference was due to a putative steric overlap between the Apa-M5 scaffold and calmodulin. The peptide Apa-Cro was designed to replace the large structural protein matrix of λ Cro with the apamin disulfide scaffold. However, Apa-Cro did not bind the consensus DNA operator half-site of λ Cro, probably due to a steric overlap between the Apa-Cro disulfide framework and the DNA. The amino acid sequence of the scaffold-disulfide bridge arrangement of the peptide Max was derived from the core sequence of scyllatoxin, which contains an α-helix constrained at the C-terminal end by two disulfide bridges and a two-stranded βsheet scaffold. Max was shown to fold with >84% yield to form a predictable, stable structure that is similar to scyllatoxin. The folding and stability properties of Max make this scaffold and disulfide bridge arrangement an ideal candidate for the development of hybrid sequence peptides. The dynamics of a fraying C-terminal end of the helix of the peptide Apa-AlaN was determined by analysis of ^{15}N NMR relaxation properties.
Relation between Feynman cycles and off-diagonal long-range order.
Ueltschi, Daniel
2006-10-27
The usual order parameter for Bose-Einstein condensation involves the off-diagonal correlation function of Penrose and Onsager, but an alternative is Feynman's notion of infinite cycles. We present a formula that relates both order parameters. We discuss its validity with the help of rigorous results and heuristic arguments. The conclusion is that infinite cycles do not always represent the Bose condensate.
Propagators of Generalized Schrödinger Equations Related by First-order Supersymmetry
A. Schulze-Halberg
2011-01-01
Full Text Available We construct an explicit relation between propagators of generalized Schrödinger equations that are linked by a first-order supersymmetric transformation. Our findings extend and complement recent results on the conventional case [1].
Teeth Grinding: Is Emotional Stability related to Bruxism?
Sutin, Angelina R.; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.
2010-01-01
This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral complaints often associated with anxiety (jaw clicks, difficulty chewing food, and dry mouth), but not with more general oral health complaints (unhealthy gums, bleeding gums, and canker sores) or with dentist-assessed occlusal wear or tongue indentations. This study provides evidence for the association between Neuroticism and bruxism and other stress-related oral health symptoms. PMID:20835403
Teeth Grinding: Is Emotional Stability related to Bruxism?
Sutin, Angelina R; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T
2010-06-01
This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral complaints often associated with anxiety (jaw clicks, difficulty chewing food, and dry mouth), but not with more general oral health complaints (unhealthy gums, bleeding gums, and canker sores) or with dentist-assessed occlusal wear or tongue indentations. This study provides evidence for the association between Neuroticism and bruxism and other stress-related oral health symptoms.
Salt marsh stability modelled in relation to sea level rise
Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart
2010-01-01
Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay...... thickness. Autocompaction was incorporated in the model, and shown to play a major role for the translation of accretion rates measured as length per unit time to accumulation rates measured as mass per area per unit time. This is important, even for shallow salt marsh deposits for which it is demonstrated...... that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt...
Teeth Grinding: Is Emotional Stability related to Bruxism?
Sutin, Angelina R; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T.
2010-01-01
This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral c...
Local stability of a gravitating filament: a dispersion relation
Freundlich, Jonathan; Combes, Françoise
2014-01-01
Filamentary structures are ubiquitous in astrophysics and are observed at various scales. On a cosmological scale, matter is usually distributed along filaments, and filaments are also typical features of the interstellar medium. Within a cosmic filament, matter can contract and form galaxies, whereas an interstellar gas filament can clump into a series of bead-like structures which can then turn into stars. To investigate the growth of such instabilities, we derive a local dispersion relation for an idealized self-gravitating filament, and study some of its properties. Our idealized picture consists of an infinite self-gravitating and rotating cylinder with pressure and density related by a polytropic equation of state. We assume no specific density distribution, treat matter as a fluid, and use hydrodynamics to derive the linearized equations that govern the local perturbations. We obtain a dispersion relation for axisymmetric perturbations and study its properties in the (k_R, k_z) phase space, where k_R a...
Toward a Consistent Framework for High Order Mesh Refinement Schemes in Numerical Relativity
Mongwane, Bishop
2015-01-01
It has now become customary in the field of numerical relativity to couple high order finite difference schemes to mesh refinement algorithms. To this end, different modifications to the standard Berger-Oliger adaptive mesh refinement algorithm have been proposed. In this work we present a fourth order stable mesh refinement scheme with sub-cycling in time for numerical relativity. We do not use buffer zones to deal with refinement boundaries but explicitly specify boundary data for refined grids. We argue that the incompatibility of the standard mesh refinement algorithm with higher order Runge Kutta methods is a manifestation of order reduction phenomena, caused by inconsistent application of boundary data in the refined grids. Our scheme also addresses the problem of spurious reflections that are generated when propagating waves cross mesh refinement boundaries. We introduce a transition zone on refined levels within which the phase velocity of propagating modes is allowed to decelerate in order to smoothl...
Salt marsh stability modelled in relation to sea level rise
Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart
2010-01-01
Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay...... rise, the marsh at the specific location will eventually drown, whereas - with a sea level rise below this level – it will grow towards the top of the rising tidal frame. The short term variation of salt marsh accretion was found to correlate well with variations in the North Atlantic Oscillation...... - relatively quickly grow above the level of the highest astronomical tide, whereas this - in practice - will never happen for the latter....
Personality traits in old age: measurement and rank-order stability and some mean-level change.
Mõttus, René; Johnson, Wendy; Deary, Ian J
2012-03-01
Lothian Birth Cohorts, 1936 and 1921 were used to study the longitudinal comparability of Five-Factor Model (McCrae & John, 1992) personality traits from ages 69 to 72 years and from ages 81 to 87 years, and cross-cohort comparability between ages 69 and 81 years. Personality was measured using the 50-item International Personality Item Pool (Goldberg, 1999). Satisfactory measurement invariance was established across time and cohorts. High rank-order stability was observed in both cohorts. Almost no mean-level change was observed in the younger cohort, whereas Extraversion, Agreeableness, Conscientiousness, and Intellect declined significantly in the older cohort. The older cohort scored higher on Agreeableness and Conscientiousness. In these cohorts, individual differences in personality traits continued to be stable even in very old age, mean-level changes accelerated.
169 On the Relative Stability of Tetraoxo-bisanthrenes Related to ...
Meyer
used in medicine for the healing of wounds and, in recent times, against alcohol ... Details on the chemistry of hypericin and its various roles and applications in ... Within a series of isomeric benzenoid molecules, the thermodynamic stability is.
Assessing the relative stabilities of engineered hemoglobins using electrospray mass spectrometry.
Apostol, I
1999-07-15
An ion trap mass spectrometer equipped with an electrospray source was used to examine the relative thermodynamic stabilities of various hemoglobins with respect to both tetramer dissociation and hemin dissociation. The results demonstrated that the stability of hemoglobin molecules can be differentiated by the amount of applied collision-induced dissociation (CID) energy necessary to break up the intact tetramer into its constituent globins. The stability of the intact tetramer was affected by single mutations in the beta-globins. The stabilities of the constituent hologlobins were assessed via trap CID of selected ions. The results demonstrated the importance of the contributions of the hologlobin components to the stability of the intact tetramer. Genetic fusion of two alpha-globins, through the introduction of a single glycine residue between the C-terminus of one alpha-chain and the N-terminus of the second, significantly increased the stability of the hemoglobin pseudo-tetramer. Chemical crosslinking of the beta-globins in addition to genetic fusion of alpha-globins further stabilized the hemoglobin molecule. A dihemoglobin molecule produced by the genetic fusion of two di-alpha-globins with a flexible linker demonstrated a decreased stability relative to the corresponding monohemoglobin.
Monodromy and Jacobi-like Relations for Color-Ordered Amplitudes
Bjerrum-Bohr, N E J; Sondergaard, Thomas; Vanhove, Pierre
2010-01-01
We discuss monodromy relations between different color-ordered amplitudes in gauge theories. We show that Jacobi-like relations of Bern, Carrasco and Johansson can be introduced in a manner that is compatible with these monodromy relations. The Jacobi-like relations are not the most general set of equations that satisfy this criterion. Applications to supergravity amplitudes follow straightforwardly through the KLT-relations. We explicitly show how the tree-level relations give rise to non-trivial identities at loop level.
Relative boundedness and compactness theory for second-order differential operators
Don B. Hinton
1997-01-01
Full Text Available The problem considered is to give necessary and sufficient conditions for perturbations of a second-order ordinary differential operator to be either relatively bounded or relatively compact. Such conditions are found for three classes of operators. The conditions are expressed in terms of integral averages of the coefficients of the perturbing operator.
Quark mass relations to four-loop order in perturbative QCD.
Marquard, Peter; Smirnov, Alexander V; Smirnov, Vladimir A; Steinhauser, Matthias
2015-04-10
We present results for the relation between a heavy quark mass defined in the on-shell and minimal subtraction (MS[over ¯]) scheme to four-loop order. The method to compute the four-loop on-shell integral is briefly described and the new results are used to establish relations between various short-distance masses and the MS[over ¯] quark mass to next-to-next-to-next-to-leading order accuracy. These relations play an important role in the accurate determination of the MS[over ¯] heavy quark masses.
Imaging of first-order surface-related multiples by reverse-time migration
Liu, Xuejian; Liu, Yike; Hu, Hao; Li, Peng; Khan, Majid
2017-02-01
Surface-related multiples have been utilized in the reverse-time migration (RTM) procedures, and additional illumination for subsurface can be provided. Meanwhile, many cross-talks are generated from undesired interactions between forward- and backward-propagated seismic waves. In this paper, subsequent to analysing and categorizing these cross-talks, we propose RTM of first-order multiples to avoid most undesired interactions in RTM of all-order multiples, where only primaries are forward-propagated and crosscorrelated with the backward-propagated first-order multiples. With primaries and multiples separated during regular seismic data processing as the input data, first-order multiples can be obtained by a two-step scheme: (1) the dual-prediction of higher-order multiples; and (2) the adaptive subtraction of predicted higher-order multiples from all-order multiples within local offset-time windows. In numerical experiments, two synthetic and a marine field data sets are used, where different cross-talks generated by RTM of all-order multiples can be identified and the proposed RTM of first-order multiples can provide a very interpretable image with a few cross-talks.
Relative stability of network states in Boolean network models of gene regulation in development.
Zhou, Joseph Xu; Samal, Areejit; d'Hérouël, Aymeric Fouquier; Price, Nathan D; Huang, Sui
2016-01-01
Progress in cell type reprogramming has revived the interest in Waddington's concept of the epigenetic landscape. Recently researchers developed the quasi-potential theory to represent the Waddington's landscape. The Quasi-potential U(x), derived from interactions in the gene regulatory network (GRN) of a cell, quantifies the relative stability of network states, which determine the effort required for state transitions in a multi-stable dynamical system. However, quasi-potential landscapes, originally developed for continuous systems, are not suitable for discrete-valued networks which are important tools to study complex systems. In this paper, we provide a framework to quantify the landscape for discrete Boolean networks (BNs). We apply our framework to study pancreas cell differentiation where an ensemble of BN models is considered based on the structure of a minimal GRN for pancreas development. We impose biologically motivated structural constraints (corresponding to specific type of Boolean functions) and dynamical constraints (corresponding to stable attractor states) to limit the space of BN models for pancreas development. In addition, we enforce a novel functional constraint corresponding to the relative ordering of attractor states in BN models to restrict the space of BN models to the biological relevant class. We find that BNs with canalyzing/sign-compatible Boolean functions best capture the dynamics of pancreas cell differentiation. This framework can also determine the genes' influence on cell state transitions, and thus can facilitate the rational design of cell reprogramming protocols.
Muhammad H. Al-Malack
2016-07-01
Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.
LUO Xiao-hua; WU Mu-ying; HE Wei; SHAO Ming-zhu; LUO Shi-yu
2011-01-01
Under classical mechanics, the general equation of particle motion in the periodic field is derived. In the dampless case, the existence possibility of the higher-order harmonic radiation is explored by using Bessel function expansion of a generalized trigonometrical function and the multi-scale method. In the damping case, the critical properties and a chaotic behavior are discussed by the Melnikov method. The results show that the use of a higher-order harmonic radiation of non-relativistic particles as a short-wavelength laser source is perfectly possible, and the system's critical condition is related to its parameters. Only by adjusting parameters suitablely, the stable higher-order harmonic radiation with bigger intensity can be obtained.
Exploring Item Order in Anxiety-Related Constructs: Practical Impacts of Serial Position
R. Nicholas Carleton
2012-04-01
Full Text Available The present study was designed to test for item order effects by measuring four distinct constructs that contribute substantively to anxiety-related psychopathology (i.e., anxiety sensitivity, fear of negative evaluation, injury/illness sensitivity, and intolerance of uncertainty. Participants (n = 999; 71% women were randomly assigned to complete measures for each construct presented in one of two modalities: (a items presented cohesively as measures or (b items presented randomly interspersed with one another. The results suggested that item order had a relatively small impact on item endorsement, response patterns, and reliabilities. The small impact was such that item order appears unlikely to influence clinical decisions related to these measures. These findings not only have implications for these and other similar measures, but further inform a long-standing debate about whether item grouping is a substantial concern in measurement.
El-Gindy, Alaa; Attia, Khalid A; Nassar, Mohammad Wafaa; Al Abasawi, Nasr M; Al-Shabrawi, Maisra
2011-01-01
A validated stability-indicating HPLC method was developed for the analysis of azithromycin (AZ) and its related compounds in raw materials, capsule, and suspension using an Xterra RP C18 column at 50 degrees C with UV detection at 215 nm. Isocratic elution was employed using the mobile phase 14 mM disodium hydrogen phosphate (pH 10.5, adjusted by 1 M NaOH)-methanol-acetonitrile-tetrahydrofuran (40.0 + 30.0 + 30.0 + 0.1, v/v/v/v). AZ and 14 of its related compounds were separated and quantified. The described method was linear over the range of 2-1800 microg/mL AZ with (r = 0.9999). The stability of AZ was studied under accelerated acidic, alkaline, and oxidative conditions. The proposed method was used to investigate the kinetics of acidic and alkaline hydrolysis process of AZ at different temperatures, and the apparent pseudo first-order rate constant, half-life, and activation energy were calculated. The major peak detected from the degradation of AZ in alkaline and acidic conditions was decladinosylazithromycine, while azithromycin N-oxide was detected from the oxidative degradation. Long-term stability studies for capsule and oral suspension were carried out. The proposed stability-indicating method was completely validated according to the U.S. Food and Drug Administration requirements.
Lopuszynski, Michal; Majewski, Jacek A.
2007-01-01
We present theoretical studies for the third-order elastic constants $C_{ijk}$ in zinc-blende nitrides AlN, GaN, and InN. Our predictions for these compounds are based on detailed ab initio calculations of strain-energy and strain-stress relations in the framework of the density functional theory. To judge the computational accuracy, we compare the ab initio calculated results for $C_{ijk}$ with experimental data available for Si and GaAs. We also underline the relation of the third-order ela...
Stability of the classical type of relative equilibria of a rigid body in the J2 problem
Wang, Yue
2013-01-01
The motion of a point mass in the J2 problem is generalized to that of a rigid body in a J2 gravity field. The linear and nonlinear stability of the classical type of relative equilibria of the rigid body, which have been obtained in our previous paper, are studied in the framework of geometric mechanics with the second-order gravitational potential. Non-canonical Hamiltonian structure of the problem, i.e., Poisson tensor, Casimir functions and equations of motion, are obtained through a Poisson reduction process by means of the symmetry of the problem. The linear system matrix at the relative equilibria is given through the multiplication of the Poisson tensor and Hessian matrix of the variational Lagrangian. Based on the characteristic equation of the linear system matrix, the conditions of linear stability of the relative equilibria are obtained. The conditions of nonlinear stability of the relative equilibria are derived with the energy-Casimir method through the projected Hessian matrix of the variationa...
Stability and relative validity of the Multiple Sclerosis Impact Profile (MSIP)
Wynia, K.; Middel, B.; de Ruiter, H.; van Dijk, J.P.; de Keyser, J.H.A; Reijneveld, S.A.
2008-01-01
Objective. To examine the stability and relative validity of the Multiple Sclerosis Impact Profile (MSIP) in criterion-related groups. The MSIP is a disease-targeted health impact measure based on a selection of International Classification of Functioning, Disability and Health (ICF) aspects selecte
Stability and relative validity of the Multiple Sclerosis Impact Profile (MSIP)
Wynia, K.; Middel, B.; de Ruiter, H.; van Dijk, J.P.; de Keyser, J.H.A; Reijneveld, S.A.
2008-01-01
Objective. To examine the stability and relative validity of the Multiple Sclerosis Impact Profile (MSIP) in criterion-related groups. The MSIP is a disease-targeted health impact measure based on a selection of International Classification of Functioning, Disability and Health (ICF) aspects
Stability and relative validity of the Neuromuscular Disease Impact Profile (NMDIP)
Bos, Isaac; Kuks, Jan B. M.; Almansa, Josue; Kremer, Hubertus P. H.; Wynia, Klaske
2017-01-01
Background: The aim of this study was to examine the stability and relative validity (RV) of the Neuromuscular Disease Impact Profile (NMDIP) using criterion-related groups. In a previous study the NMDIP-scales showed good internal consistency, convergent and discriminant validity. Known-groups
Parity- and Time Reversal-Violating Pion Nucleon Couplings: Higher Order Chiral Matching Relations
Seng, Chien-Yeah
2016-01-01
Parity- and time reversal-violating (PVTV) pion-nucleon couplings govern the magnitude of long-range contributions to nucleon and atomic electric dipole moments. When these couplings arise from chiral symmetry-breaking CP-violating operators, such as the QCD $\\theta$-term or quark chromoelectric dipole moments, one may relate hadronic matrix elements entering the PVTV couplings to nucleon and pion mass shifts by exploiting the corresponding chiral transformation properties at leading order (LO) in the chiral expansion. We compute the higher-order contributions to the lowest order relations arising from chiral loops and next-to-next-to leading order (NNLO) operators. We find that for the QCD $\\theta$-term the higher order contributions are analytic in the quark masses, while for the quark chromoelectric dipole moments and chiral symmetry-breaking four-quark operators, the matching relations also receive non-analytic corrections. Numerical estimates suggest that for the isoscalar PVTV pion-nucleon coupling, the...
High-Order Numerical-Relativity Simulations of Binary Neutron Stars
Radice, David; Galeazzi, Filippo
2015-01-01
We report simulations of the inspiral and merger of binary neutron stars performed with \\texttt{WhiskyTHC}, the first of a new generation of numerical relativity codes employing higher than second-order methods for both the spacetime and the hydrodynamic evolution. We find that the use of higher-order schemes improves substantially the quality of the gravitational waveforms extracted from the simulations when compared to those computed using traditional second-order schemes. The reduced de-phasing and the faster convergence rate allow us to estimate the phase evolution of the gravitational waves emitted, as well as the magnitude of finite-resolution effects, without the need of phase- or time-alignments or rescalings of the waves, as sometimes done in other works. Furthermore, by using an additional unpublished simulation at very high resolution, we confirm the robustness of our high convergence order of $3.2$.
2012-12-18
... COMMISSION Order Granting Exemptions From Certain Rules of Regulation SHO Related to Hurricane Sandy December 12, 2012. I. Introduction Hurricane Sandy made landfall along the mid-Atlantic Coast on October 29... in the Vault at the time Hurricane Sandy made landfall, facilitating DTCC's ability to...
Do Children with Autism Perceive Second-Order Relational Features? The Case of the Thatcher Illusion
Rouse, Helen; Donnelly, Nick; Hadwin, Julie A.; Brown, Tony
2004-01-01
Background: This study presents two experiments that investigated whether children with autism were susceptible to the Thatcher illusion. Perception of the Thatcher illusion requires being able to compute second-order configural relations for facial stimuli. Method: In both experiments children with autism were matched for non-verbal and verbal…
Exploring Item Order in Anxiety-Related Constructs: Practical Impacts of Serial Position
Carleton, R. Nicholas; Thibodeau, Michel A.; Osborne, Jason W.; Asmundson, Gordon J. G.
2012-01-01
The present study was designed to test for item order effects by measuring four distinct constructs that contribute substantively to anxiety-related psychopathology (i.e., anxiety sensitivity, fear of negative evaluation, injury/illness sensitivity, and intolerance of uncertainty). Participants (n = 999; 71% women) were randomly assigned to…
无
2010-01-01
In this paper, we study an even order neutral differential equation with deviating arguments, and obtain new oscillation results without the assumptions which were required for related results given before. Our results extend and improve many known oscillation criteria, based on the standard integral averaging technique.
Collision Index and Stability of Elliptic Relative Equilibria in Planar {n} -body Problem
Hu, Xijun; Ou, Yuwei
2016-06-01
It is well known that a planar central configuration of the {n} -body problem gives rise to solutions where each particle moves on a specific Keplerian orbit while the totality of the particles move on a homographic motion. When the eccentricity {e} of the Keplerian orbit belongs in {[0,1)} , following Meyer and Schmidt, we call such solutions elliptic relative equilibria (shortly, ERE). In order to study the linear stability of ERE in the near-collision case, namely when {1-e} is small enough, we introduce the collision index for planar central configurations. The collision index is a Maslov-type index for heteroclinic orbits and orbits parametrised by half-lines that, according to the definition given by Hu and Portaluri (An index theory for unbounded motions of Hamiltonian systems, Hu and Portaluri (2015, preprint)), we shall refer to as half-clinic orbits and whose definition in this context, is essentially based on a blow up technique in the case {e=1} . We get the fundamental properties of collision index and approximation theorems. As applications, we give some new hyperbolic criteria and prove that, generically, the ERE of minimal central configurations are hyperbolic in the near-collision case, and we give a detailed analysis of Euler collinear orbits in the near-collision case.
Ballesteros, Daniel; Walters, Christina
2007-01-01
Ex situ conservation of ferns may be accomplished by maintaining the viability of stored spores for many years. Storage conditions that maximize spore longevity can be inferred from an understanding of the behaviour of water within fern spores. Water sorption properties were measured in spores of five homosporeous species of ferns and compared with properties of pollen, seeds, and fern leaf tissue. Isotherms were constructed at 5, 25, and 45 degrees C and analysed using different physicochemical models in order to quantify chemical affinity and heat (enthalpy) of sorption of water in fern spores. Fern spores hydrate slowly but dry rapidly at ambient relative humidity. Low Brunauer-Emmet-Teller monolayer values, few water-binding sites according to the D'Arcy-Watt model, and limited solute-solvent compatibility according to the Flory-Huggins model suggest that fern spores have low affinity for water. Despite the low water affinity, fern spores demonstrate relatively high values of sorption enthalpy (DeltaH(sorp)). Parameters associated with binding sites and DeltaH(sorp) decrease with increasing temperature, suggesting temperature- and hydration-dependent changes in volume of spore macromolecules. Collectively, these data may relate to the degree to which cellular structures within fern spores are stabilized during drying and cooling. Water sorption properties within fern spores suggest that storage at subfreezing temperatures will give longevities comparable with those achieved with seeds. However, the window of optimum water contents for fern spores is very narrow and much lower than that measured in seeds, making precise manipulation of water content imperative for achieving maximum longevity.
Akhtar, Imran; Nayfeh, Ali H.; Ribbens, Calvin J.
2009-07-01
Proper orthogonal decomposition (POD) has been used to develop a reduced-order model of the hydrodynamic forces acting on a circular cylinder. Direct numerical simulations of the incompressible Navier-Stokes equations have been performed using a parallel computational fluid dynamics (CFD) code to simulate the flow past a circular cylinder. Snapshots of the velocity and pressure fields are used to calculate the divergence-free velocity and pressure modes, respectively. We use the dominant of these velocity POD modes (a small number of eigenfunctions or modes) in a Galerkin procedure to project the Navier-Stokes equations onto a low-dimensional space, thereby reducing the distributed-parameter problem into a finite-dimensional nonlinear dynamical system in time. The solution of the reduced dynamical system is a limit cycle corresponding to vortex shedding. We investigate the stability of the limit cycle by using long-time integration and propose to use a shooting technique to home on the system limit cycle. We obtain the pressure-Poisson equation by taking the divergence of the Navier-Stokes equation and then projecting it onto the pressure POD modes. The pressure is then decomposed into lift and drag components and compared with the CFD results.
Akhtar, Imran [Virginia Tech, Department of Engineering Science and Mechanics, MC 0219, Blacksburg, VA (United States); Virginia Tech, Interdisciplinary Center for Applied Mathematics, MC 0531, Blacksburg, VA (United States); Nayfeh, Ali H. [Virginia Tech, Department of Engineering Science and Mechanics, MC 0219, Blacksburg, VA (United States); Ribbens, Calvin J. [Virginia Tech, Department of Computer Science, Blacksburg, VA (United States)
2009-07-15
Proper orthogonal decomposition (POD) has been used to develop a reduced-order model of the hydrodynamic forces acting on a circular cylinder. Direct numerical simulations of the incompressible Navier-Stokes equations have been performed using a parallel computational fluid dynamics (CFD) code to simulate the flow past a circular cylinder. Snapshots of the velocity and pressure fields are used to calculate the divergence-free velocity and pressure modes, respectively. We use the dominant of these velocity POD modes (a small number of eigenfunctions or modes) in a Galerkin procedure to project the Navier-Stokes equations onto a low-dimensional space, thereby reducing the distributed-parameter problem into a finite-dimensional nonlinear dynamical system in time. The solution of the reduced dynamical system is a limit cycle corresponding to vortex shedding. We investigate the stability of the limit cycle by using long-time integration and propose to use a shooting technique to home on the system limit cycle. We obtain the pressure-Poisson equation by taking the divergence of the Navier-Stokes equation and then projecting it onto the pressure POD modes. The pressure is then decomposed into lift and drag components and compared with the CFD results. (orig.)
Mediator of moderators: temporal stability of intention and the intention-behavior relation.
Sheeran, Paschal; Abraham, Charles
2003-02-01
Intention certainty, past behavior, self-schema, anticipated regret, and attitudinal versus normative control all have been found to moderate intention-behavior relations. It is argued that moderation occurs because these variables produce "strong" intentions. Stability of intention over time is a key index of intention strength. Consequently, it was hypothesized that temporal stability of intention would mediate moderation by these other moderators. Participants (N = 185) completed questionnaire measures of theory of planned behavior constructs and moderator variables at two time points and subsequently reported their exercise behavior. Findings showed that all of the moderators, including temporal stability, were associated with significant improvements in consistency between intention and behavior. Temporal stability also mediated the effects of the other moderators, supporting the study hypothesis.
Bocchinfuso, Gianfranco; Mazzuca, Claudia; Conflitti, Paolo; Cori, Davide; Coviello, Tommasina; Palleschi, Antonio
2016-09-01
Scleroglucan (Sclg) is a polysaccharide that exhibits a triple helix conformation (triplex), both in aqueous solution and in the solid state, which is lost in DMSO solution, at high temperature and at high pH values. The triplex conformation is characterized by a high rigidity, responsible of Sclg peculiar properties. Although the relative stability of triplex and single strand has already been investigated, different structural details are still missing. In the present study, we analyse the structural properties and the factors stabilizing the single chain and the triple helix of Sclg in different conditions. To this end, we simulated both systems in water and in DMSO. The triple helix has been also simulated in the presence of chemical damages on one of the three strands (to reproduce in silico the effect of sonication) or by inducing a partial unfolding of the triplex structure. The computational results have been compared with experimental evidences in which the triplex denaturation, at alkaline pH values, has been followed by monitoring the UV and CD spectra of Congo red, used as a probe molecule. Our results indicate that sonication breaks the Sclg chains without appreciably changing the stability of the other tracts of triple helix. The simulated perturbed or partially unfolded triplexes show a clear tendency to form less ordered aggregates. Finally, our simulations put in evidence an important role of the hydrophobic interactions both in the triplex stability and in the aggregation processes observed after induced denaturation.
On the relation between hydrogen bonds, tetrahedral order and molecular mobility in model water
Pereyra, R G; Malaspina, D C; Carignano, M A
2013-01-01
We studied by molecular dynamics simulations the relation existing between the lifetime of hydrogen bonds, the tetrahedral order and the diffusion coefficient of model water. We tested four different models: SPC/E, TIP4P-Ew, TIP5P-Ew and Six-site, these last two having sites explicitly resembling the water lone pairs. While all the models perform reasonably well at ambient conditions, their behavior is significantly different for temperatures below 270 K. The models with explicit lone-pairs have a longer hydrogen bond lifetime, a better tetrahedral order and a smaller diffusion coefficient than the models without them.
Matsumoto, Rie; Arai, Hiroko; Yuasa, Shinji; Imamura, Hiroshi
2017-04-01
The efficiency of spin-transfer-torque (STT) switching and the thermal-stability factor are important figures of merit in STT-based magnetoresistive random-access memory. We derive analytical expressions of the STT-switching efficiency and the thermal-stability factor for a perpendicularly magnetized spin-valve nanopillar with the first- and the second-order uniaxial magnetic anisotropy. It is shown that the STT-switching efficiency is maximized when the effective first-order anisotropy constant (Ku 1 ,eff ) is equal to the second-order anisotropy constant (Ku 2). It is also shown that the thermal-stability factor is most (least) sensitive to a variation of the applied current when Ku 2=-0.41 (0.70) Ku 1 ,eff.
Cebulak, Pola
2012-01-01
In the period since the end of the Cold War, the different layers of law in the international arena have become more interlinked and interwoven. This shift might suggest a development towards a legal “melting pot” involving an increased cross-application of judicial norms stemming from different.......” Hence, for instance, the Court of Justice of the EU has taken an active role in ensuring the effet utile of European law. This article discusses possible theoretical perspectives on the interactions between various legal orders in the international arena. The opposition between the dualist and monist...... not in fact lie exactly at the level of differentiating the relations between legal orders within or beyond the state. One could use both the monist and dualist theories to explain the hierarchy of transnational legal orders while applying constitutionalism and pluralism on the purely national level...
Britz, Dieter; Østerby, Ole
1994-01-01
A reported analysis of the stability of some digital simulation methods is investigated by numerical experiments and the results are consistent with the analysis. Traditional stability conditions need to be modified slightly in the presence of homogeneous reactions, though not to a degree that ha...
Monteiro Maria do Carmo
1998-01-01
Full Text Available Electrophoretic thermostability tests of soluble malate dehydrogenases (sMDH isozymes in tissue extracts of 21 subtropical fish belonging to the orders Characiformes, Siluriformes and Perciformes showed three distinct results. The first, characterized by thermal stability of the slowest-migrating band or A-isoform, was detected in 52% of all species. The second, exhibited in 29% of the species analyzed, had a bidirectionally divergent pattern of their sMDH locus expression, and was characterized by a nondivergent thermostability pattern of both sMDH-A* and B*. In the third category, obtained in 19% of the species studied (the four Siluriformes species, thermostability of the fastest-migrating bands, or B-isoforms, was observed. Comparison of the effects of habitat temperature on the activity of paralogous and orthologous isoforms in tissue extracts of two of these species with different thermostability properties (Leporinus friderici - thermostable sMDH-A*, and Pimelodus maculatus - reverse thermostability properties or reverse electrophoretic pattern, collected during winter and summer months, showed that A and B subunits were present at different quantitative levels and their activities were nearly season independent. Differences in susceptibility to temperature (50°C of both sMDH loci from tissue extracts of these species were found. In P. maculatus, these susceptibilities helped strengthen one of the hypotheses: the reverse thermostability pattern, where the fastest-migrating band or the B-isoform was the thermostable sMDH. Thus, temperature differences among orthologous homologues of sMDH seem to have occurred in these acclimatized species, where the fastest-migrating band, usually muscle specific and thermolabile in most teleosts, appeared in P. maculatus as the thermostable isoform.
van Wüllen, Christoph
2004-04-22
Wolf et al. have recently investigated a generalized Douglas-Kroll transformation. From a general class of unitary transformations that can be used in the Douglas-Kroll transformation, they pick one which is supposed to give, at a given order, an optimal transformed Dirac Hamiltonian. Results were presented through the fifth order. However, no data were given to demonstrate to which extent the so-called "optimal" Douglas-Kroll transformation is superior to other choices. In this work, the Douglas-Kroll transformation is extended to the sixth order for the first time, using computer algebra algorithms to obtain the working equations. It is shown how, at a given order, different variants of the Douglas-Kroll Hamiltonians are related. Various choices of the generalized transformation are examined numerically for the ground states of the one-electron atomic ions with nuclear charges Z=20, 40, 60, 80, 100, and 120. It is shown that compared to the improvement obtained by including the next order, the differences between various choices for the generalized Douglas-Kroll transformation are almost negligible. Results closest to the Dirac eigenvalues are not obtained with the optimal Douglas-Kroll transformation given by Wolf et al., but with the parametrization originally suggested by Douglas and Kroll.
Beyond second-order convergence in simulations of binary neutron stars in full general-relativity
Radice, David; Galeazzi, Filippo
2013-01-01
Despite the recent rapid progress in numerical relativity, a convergence order less than the second has so far plagued codes solving the Einstein-Euler system of equations. We report simulations of the inspiral of binary neutron stars in quasi-circular orbits computed with a new code employing high-order, high-resolution shock-capturing, finite-differencing schemes that, for the first time, go beyond the second-order barrier. In particular, without any tuning or alignment, we measure a convergence order above three both in the phase and in the amplitude of the gravitational waves. Because the new code is able to calculate waveforms with very small phase errors already at modest resolutions, we are able to obtain accurate estimates of tidal effects in the inspiral that are essentially free from the large numerical viscosity typical of lower-order methods, and even for the challenging large compactness and small-deformability binary considered here. We find a remarkable agreement between our Richardson-extrapol...
Kroeze, R. J.; van der Veen, A. J.; van Royen, B. J.; Bank, R. A.; Helder, M. N.; Smit, T. H.
2013-01-01
To relate the progress of vertebral segmental stability after interbody fusion surgery with radiological assessment of spinal fusion. Twenty goats received double-level interbody fusion and were followed for a period of 3, 6 and 12 months. After killing, interbody fusion was assessed
Kroeze, R. J.; van der Veen, A. J.; van Royen, B. J.; Bank, R. A.; Helder, M. N.; Smit, T. H.
2013-01-01
To relate the progress of vertebral segmental stability after interbody fusion surgery with radiological assessment of spinal fusion. Twenty goats received double-level interbody fusion and were followed for a period of 3, 6 and 12 months. After killing, interbody fusion was assessed radiographicall
Toddlers' Temperament Profiles: Stability and Relations to Negative and Positive Parenting
van den Akker, Alithe L.; Dekovic, Maja; Prinzie, Peter; Asscher, Jessica J.
2010-01-01
This study investigated the type and stability of temperament profiles in toddlers, and relations of profile probability to negative and positive parenting trajectories. Mothers (N = 96) rated their child's (41 girls and 54 boys) Sociability, Anger Proneness, and Activity Level four times during 1 year. The assessment of parenting included both…
Toddlers' temperament profiles: stability and relations to negative and positive parenting
A.L. van den Akker; M. Deković; P. Prinzie; J.J. Asscher
2010-01-01
This study investigated the type and stability of temperament profiles in toddlers, and relations of profile probability to negative and positive parenting trajectories. Mothers (N = 96) rated their child’s (41 girls and 54 boys) Sociability, Anger Proneness, and Activity Level four times during 1
Access Graphs Results for LRU versus FIFO under Relative Worst Order Analysis
Boyar, Joan; Larsen, Kim S
2012-01-01
Access graphs, which have been used previously in connection with competitive analysis to model locality of reference in paging, are considered in connection with relative worst order analysis. In this model, FWF is shown to be strictly worse than both LRU and FIFO on any access graph. LRU is shown to be strictly better than FIFO on paths and cycles, but they are incomparable on some families of graphs which grow with the length of the sequences.
On Sequences of Numbers and Polynomials Defined by Linear Recurrence Relations of Order 2
Tian-Xiao He
2009-01-01
Full Text Available Here we present a new method to construct the explicit formula of a sequence of numbers and polynomials generated by a linear recurrence relation of order 2. The applications of the method to the Fibonacci and Lucas numbers, Chebyshev polynomials, the generalized Gegenbauer-Humbert polynomials are also discussed. The derived idea provides a general method to construct identities of number or polynomial sequences defined by linear recurrence relations. The applications using the method to solve some algebraic and ordinary differential equations are presented.
Unintended Transformations of Clinical Relations with a Computerized Physician Order Entry System
Wentzer, Helle; Böttger, Ulrich; Boye, Niels
2007-01-01
A socio-technical approach was used to study the qualitative effects of deploying a medication CPOE (Computerized Physician Order Entry System with no decision support) at two internal medical wards in a hospital in Denmark. Our results show spatial and temporal transformations of core acts...... and relations in medication work, i.e. of the intended use of the system inscribed in hardware and software, in the relations of care between doctors and patients, of collaboration between doctors and nurses, and prospectively of the patients’ trajectories when readmitted to hospital or another health care...... institution, reusing data from the system. This study throws light on problems of continuity of patient care paths, patient-related and IT-system-related error handling and time spent on core activities – when ubiquitous IT is used locally in a real physical setting with specific traditions of performing...
Lee, Jennifer E.; Watson, David; Frey Law, Laura A.
2010-01-01
Pain is a debilitating condition affecting millions each year, yet what predisposes certain individuals to be more sensitive to pain remains relatively unknown. Several psychological factors have been associated with pain perception, but the structural relations between multiple higher- and lower-order constructs and pain are not well understood. Thus, we aimed to examine the associations between pain perception using the cold pressor task (CPT), higher-order personality traits (neuroticism, ...
Stability and relative validity of the Multiple Sclerosis Impact Profile (MSIP)
Wynia, K.; Middel, B; Ruiter, H.; van Dijk, J. P.; de Keyser, J.H.A.; Reijneveld, S A
2008-01-01
Objective. To examine the stability and relative validity of the Multiple Sclerosis Impact Profile (MSIP) in criterion-related groups. The MSIP is a disease-targeted health impact measure based on a selection of International Classification of Functioning, Disability and Health (ICF) aspects selected by 98 patients and medical and non-medical health professionals. Method. Data were obtained from a postal survey of 377 individuals with Multiple Sclerosis (MS) attending the MS centre of the Uni...
Stability and relative validity of the Neuromuscular Disease Impact Profile (NMDIP)
Bos, Isaac; Kuks, Jan B. M.; Almansa, Josue; Hubertus P H Kremer; Wynia, Klaske
2017-01-01
Background: The aim of this study was to examine the stability and relative validity (RV) of the Neuromuscular Disease Impact Profile (NMDIP) using criterion-related groups. In a previous study the NMDIP-scales showed good internal consistency, convergent and discriminant validity. Known-groups analysis showed that the NMDIP discriminates between categories of extent of limitations. Methods: A cross-sectional postal survey study was performed on patients diagnosed with a NMD and registered at...
Stability of relative equilibria of point vortices on a sphere and symplectic integrators
Marsden, J.E.; Pekarsky, S. [California Institute of Technology, Pasadena, CA (United States); Shkoller, S. [California Institute of Technology, Pasadena, CA (United States); Los Alamos National Lab., Los Alamos, NM (United States)
1999-12-01
This paper analyzes the dynamics of {nu} point vortices moving on a sphere from the point of view of geometric mechanics. The formalism is developed for the general case of {nu} vortices, and the details are provided for the (integrable) case {nu}=3. Stability of relative equilibria is analyzed by the energy-momentum method. Explicit criteria for stability of different configurations with generic and non-generic momenta are obtained. In each case, a group of transformations is specified, such that motion in the original phase space is stable module this group. Finally, the construction of a symplectic-momentum integrator for vortex dynamics on a sphere is outlined.
ZHANG Xiangmu; MA Wenjuan; CUI Shuwen; WANG Lihua
2006-01-01
Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B20 and the magnetic exchange interaction was studied as temperature approaches to 0K. The results show that the stabilization energy contributed by Tb3+ is linear with crystal field coefficient B20 approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substancessuch as TbCo5, Tb2Co17 and Tb2Fe14B compounds.
Encinas, A. H.; Gayoso-Martínez, V.; Martín Del Rey, A.; Martín-Vaquero, J.; Queiruga-Dios, A.
2016-03-01
In this paper, we discuss the problem of solving nonlinear Klein-Gordon equations (KGEs), which are especially useful to model nonlinear phenomena. In order to obtain more exact solutions, we have derived different fourth- and sixth-order, stable explicit and implicit finite difference schemes for some of the best known nonlinear KGEs. These new higher-order methods allow a reduction in the number of nodes, which is necessary to solve multi-dimensional KGEs. Moreover, we describe how higher-order stable algorithms can be constructed in a similar way following the proposed procedures. For the considered equations, the stability and consistency of the proposed schemes are studied under certain smoothness conditions of the solutions. In addition to that, we present experimental results obtained from numerical methods that illustrate the efficiency of the new algorithms, their stability, and their convergence rate.
Oligosaccharides implicated in recognition are predicted to have relatively ordered structures.
Almond, Andrew; Petersen, Bent O; Duus, Jens Ø
2004-05-18
Fucosylated O- and N-linked glycans are essential recognition molecules in plants and animals. To understand how they impart their functions, through interactions with proteins, requires a detailed analysis of structure and dynamics, but this is presently lacking. In this study, the three-dimensional structure and dynamics of three fucosylated oligosaccharides are investigated using a combination of high field (800 MHz) nuclear magnetic resonance and long (50 ns) molecular dynamics simulations in explicit water. Predictions from dynamics simulations were in agreement with nuclear Overhauser cross-peak intensities. Similarly, a theory of weak alignment in neutral media resulted in reasonable predictions of residual dipolar couplings for the trisaccharide fucosyllactose. However, for larger penta- and hexasaccharides (LNF-1 and LND-1), the anisotropic component of the alignment was underestimated, attributed to shape irregularities of the fucosyl branches on an otherwise linear core, being more pronounced in a singly branched than a doubly branched oligosaccharide. Simulations, confirmed by experiment, predicted fucosylated molecules that are restricted to librations about a single average conformation. This restriction is partly due to microscopic water interactions, which act to stabilize intramolecular hydrogen bonds and maintain tight and ordered conformations; a view not forthcoming from simpler, nonaqueous simulations. Such a conclusion is crucial for understanding how these molecules interact with proteins and impart their recognition properties.
Gravitational waveforms in scalar-tensor gravity at 2PN relative order
Sennett, Noah; Buonanno, Alessandra
2016-01-01
We compute the gravitational waveform from a binary system in scalar-tensor gravity at 2PN relative order. We restrict our calculation to non-spinning binary systems on quasi-circular orbits and compute the spin-weighted spherical modes of the radiation. The evolution of the phase of the waveform is computed in the time and frequency domains. The emission of dipolar radiation is the lowest-order dissipative process in scalar-tensor gravity. However, stringent constraints set by current astrophysical observations indicate that this effect is subdominant to quadrupolar radiation for most prospective gravitational-wave sources. We compute the waveform for systems whose inspiral is driven by: (a) dipolar radiation (e.g., binary pulsars or spontaneously scalarized systems) and (b) quadrupolar radiation (e.g., typical sources for space-based and ground-based detectors).
Studies of some problems related to atomic ordering, molecular motion and pair distribution function
Levashov, Valentin A.
In this thesis the results of my work on three out of four projects on which I was working during my Ph.D. under supervision of Prof. M. F. Thorpe are summarized. The first project was devoted to the study of properties of a model that was developed to reproduce the ordering of ions in layered double hydroxides. In the model two types of positive ions occupy the sites of triangular lattice. The ordering of ions is assumed to occur due to the long-range Coulomb interaction. The charge neutrality is provided by the negative background charge, which is assumed to be the same at every site of the lattice. General properties of the model in 1d and 2d were studied and the phase diagrams were obtained. The obtained results predict multiple phase separations in this system of charges that can, in particularly, affect the stability of the layered double hydroxides. Some properties of the atomic pair distribution function (PDF) were studied during my work on the second project. Traditionally PDF was used to study atomic ordering at small distances, while it was assumed that at large distances PDF is featureless. Puzzled by the observation that PDF calculated for the crystalline Ni does not decay at large distances we studied the behavior, in particularly the origin of decay, of PDF at large distances. The obtained results potentially could be used to measure the amount of imperfections in crystalline materials and to test instrumental resolution in X-ray and neutron diffraction experiments. During my work on the third project we were developing a technique that would allow accurate calculation of PDF for the flexible molecules. Since quantum mechanical calculations are complicated and computationally demanding in calculations of PDF for molecules in liquid or gaseous phases, classical methods, like molecular dynamics are usually employed. Thus, quantum mechanical effects, like zero-point atomic motion, are usually ignored. However, it is necessary to take into account the
Gavrilović Milica
2015-01-01
Full Text Available In today's economy, which is burdened by problems such as non-productive economy, high unemployment rates, constant inflationary pressures, great attention is paid to the interaction of monetary and fiscal policies in order to achieve macroeconomic stability. There is no universal model of economic policy even in countries around the world, nor in the Serbian economy, and policy makers are looking for the optimal design of monetary and fiscal strategies and their synchronization with other non-negligible specific economic policy objectives (in terms of balance of payments, objectives related to foreign currency course, the distribution of income, implemented stage of market reforms of the nineties, and then phase of reforms in the first decade of the 21st century. How good coordination of monetary and fiscal measures can be no qualitative basis, or as it is not possible to reconstruct and degrade previous economic structure, and that there is no definition of the new strategy, and continued the process of reforming and in the period from the time of deepening global financial crisis in 2008 . The Republic of Serbia, a country whose economy in the long process of reforming, seeks better use of comparative advantages, encouraging production and employment, adequate planning and allocation of available resources of its own and charge, absorption of new technologies, intensifying exports, encouraging investment, and with a constant potential danger which increase the vulnerability of small economies. The solid foundations of macroeconomic stability and discipline must be in production, proper allocation of resources, which will run the economy, and then increase the employment rate, and therefore national income. of crucial importance of good projections of macroeconomic aggregates, because of them depend on public revenue and public expenditure.
Lefort, Ronan; Guégan, Régis; Guendouz, Mohammed; Zanotti, Jean-Marc; Frick, Bernhard; 10.1103/PhysRevE.78.040701
2009-01-01
We analyze the molecular dynamics heterogeneity of the liquid crystal 4-n-octyl-4'-cyanobiphenyl nanoconfined in porous silicon. We show that the temperature dependence of the dynamic correlation length ?wall, which measures the distance over which a memory of the interfacial slowing down of the molecular dynamics persists, is closely related to the growth of the short-range static order arising from quenched random fields. More generally, this result may also shed some light on the connection between static and dynamic heterogeneities in a wide class of condensed and soft matter systems.
Fang, L.; Zhang, Y. J.; Fang, J.; Zhu, Y.
2016-08-01
We show by direct numerical simulations (DNSs) that in different types of isotropic turbulence, the fourth-order statistical invariants have approximately a linear relation, which can be represented by a straight line in the phase plane, passing two extreme states: the Gaussian state and the restricted Euler state. Also, each DNS case corresponds to an equilibrium region that is roughly Reynolds-dependent. In addition, both the time reversal and the compressibility effect lead to nonequilibrium transition processes in this phase plane. This observation adds a new restriction on the mean-field theory.
A stabilized 18 GHz chip-scale optical frequency comb at 2.8x10-16 relative inaccuracy
Huang, S -W; Yu, M; McGuyer, B H; Kwong, D -L; Zelevinsky, T; Wong, C W
2015-01-01
Optical frequency combs, coherent light sources that connect optical frequencies with microwave oscillations, have become the enabling tool for precision spectroscopy, optical clockwork and attosecond physics over the past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but four-wave-mixing in high-Q resonators have emerged as alternative platforms. Here we report the generation and full stabilization of CMOS-compatible optical frequency combs. The spiral microcomb's two degrees-of-freedom, one of the comb line and the native 18 GHz comb spacing, are first simultaneously phase-locked to known optical and microwave references. Second, with pump power control, active comb spacing stabilization improves the long-term stability by six orders-of-magnitude, reaching an instrument-limited 3.6 mHz/sqrt(t) residual instability. Third, referencing thirty-three of the nitride frequency comb lines against a fiber comb, we demonstrate the comb tooth-to-tooth frequency relative inaccu...
Bolan, N S; Kunhikrishnan, A; Choppala, G K; Thangarajan, R; Chung, J W
2012-05-01
There have been increasing interests in the conversion of organic residues into biochars in order to reduce the rate of decomposition, thereby enhancing carbon (C) sequestration in soils. However energy is required to initiate the pyrolysis process during biochar production which can also lead to the release of greenhouse gasses. Alternative methods can be used to stabilize C in composts and other organic residues without impacting their quality. The objectives of this study include: (i) to compare the rate of decomposition among various organic amendments and (ii) to examine the effect of clay materials on the stabilization of C in organic amendments. The decomposition of a number of organic amendments (composts and biochars) was examined by monitoring the release of carbon-dioxide using respiration experiments. The results indicated that the rate of decomposition as measured by half life (t(1/2)) varied between the organic amendments and was higher in sandy soil than in clay soil. The half life value ranged from 139 days in the sandy soil and 187 days in the clay soil for poultry manure compost to 9989 days for green waste biochar. Addition of clay materials to compost decreased the rate of decomposition, thereby increasing the stabilization of C. The half life value for poultry manure compost increased from 139 days to 620, 806 and 474 days with the addition of goethite, gibbsite and allophane, respectively. The increase in the stabilization of C with the addition of clay materials may be attributed to the immobilization of C, thereby preventing it from microbial decomposition. Stabilization of C in compost using clay materials did not impact negatively the value of composts in improving soil quality as measured by potentially mineralizable nitrogen and microbial biomass carbon in soil.
Ramani, Vijay Krishna
Polymer electrolyte membrane fuel cells (PEMFCs) have a variety of applications in the stationary power, mobile power and automotive power sectors. Existing membrane technology presently permits fuel cell operation at temperatures less than 100°C under fully saturated conditions. However, several advantages such as easier heat rejection rates and improved impurities tolerance by the anode electrocatalyst result by operating a PEMFC at elevated temperatures (above 100°C) and lower relative humidities. In an attempt to extend the operating range of the polymer electrolyte membrane, perfluorosulfonic acid (NafionRTM) based organic/inorganic (heteropolyacid) composite membranes were investigated in terms of thermal and electrochemical stability, additive stability and conductivity. Tungsten based heteropolyacids (HPAs) were found to be electrochemically stable as opposed to molybdenum based additives. The stability of the inorganic heteropolyacid additive in aqueous environments was enhanced by ion exchanging the protons of the HPAs with larger counter ions. An additional stabilization technique developed involved improving the interaction of HPA with NafionRTM by linking the particles to the sulfonic acid clusters via a sol-gel induced metal oxide linkage. The proton conductivity of the composite membranes was found to depend on the particle size of the HPA additive. A two order of magnitude change in additive particle size was attained by modification of the membrane preparation technique. This modification resulted in a nearly 50% increase in conductivity. The membranes prepared were characterized by thermal analysis, spectroscopy and microscopy. A technique was developed to incorporate existing MEA preparation and HPA stabilization techniques to the composite membranes with small HPA particles. All MEAs prepared were evaluated at high temperatures (120°C) and low relative humidities (35%) in an operating fuel cell, with membrane resistance and hence conductivity
Sana P Ansari; Saurabh K Agrawal; Subir Das
2015-01-01
This paper presents the synchronization between a pair of identical susceptible–infected–recovered (SIR) epidemic chaotic systems and fractional-order time derivative using active control method. The fractional derivative is described in Caputo sense. Numerical simulation results show that the method is effective and reliable for synchronizing the fractional-order chaotic systems while it allows the system to remain in chaotic state. The striking features of this paper are: the successful presentation of the stability of the equilibrium state and the revelation that time for synchronization varies with the variation in fractional-order derivatives close to the standard one for different specified values of the parameters of the system.
How can we strengthen students’ social relations in order to reduce school dropout?
Ingholt, Liselotte; Sørensen, Betina Bang; Andersen, Susan
2015-01-01
BACKGROUND: This article describes the rationale and contents of an intervention program aimed at strengthening students' social relations in order to reduce dropout from vocational schools in Denmark. Taking its theoretical cue from the concept of 'social participation', a qualitative study...... on ethnographic methods, including 22 qualitative interviews with students 17-19 years old and fieldwork with participant observations at four vocational schools over 40 days, including informal interviews and discussion meetings with managers, teachers, counselors and students. As part of the fieldwork, four...... additional qualitative interviews and four group interviews were conducted with students 16-25 years old. RESULTS: The qualitative data collection resulted in seven major themes to be addressed in the intervention: social relations, sole focus on professional skills, institutionalized individualization...
Related research on corneal higher-order aberrations after different ways refractive surgery
Shu-Xi He
2015-08-01
Full Text Available AIM:To evaluate the changes of corneal high-order aberration(including Coma, Spab, RMShafter laser in situ keratomileusis(LASIKwith femtosecond laser, sub-Bowman keratomileusis(SBKand laser epithelial keratomileusis(LASEK.METHODS: Of 82 myopic patients(164 eyes, 31 patients(62 eyeswere treated by FS-LASIK, 31 patients(62 eyeswere treated by SBK, 20 patients(40 eyeswere treated by LASEK. Sirius system was used for measuring the coma aberration, spherical aberration, and high order aberration at 1, 15d,1, 3mo after surgery.RESULTS: 1Vision: The uncorrected visual acuity of the three groups had no differences(P>0.05. 2Corneal aberrations: Three kinds of surgical procedure for patients with corneal aberration had significant impact. The C7, C8, C12 and RMSh of three groups were increased significantly(P0.05. The C7, C8, C12 and RMSh were not recovered to preoperative levels after 3mo. But the increase of patients after FS-LASIK was smaller than the other two groups, with statistical significance(P0.05.CONCLUSION: Compared with SBK and LASEK,FS-LASIK has better visual acuity in the early postoperative and corneal higher-order aberrations increase is relatively small.
Zhang, Changfeng; Ding, Zhansheng; Xu, Xiangbing; Wang, Qing; Qin, Guozheng; Tian, Shiping
2010-06-01
Proteome patterns in peach fruit (Prunus persica L.) stored at different low temperatures were examined in order to gain a better understanding why peach fruit is less prone to chilling injury when stored at 0 degrees C than at 5 degrees C. Some differently expressed proteins in peach fruit stored at 0 and 5 degrees C were identified using electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Among these proteins, four membrane stability related proteins, i.e., enolase, temperature-induced lipocalin, major allergen Pru p 1, and type II SK2 dehydrin were enhanced, but three proteins related to phenolic compounds metabolization, cinnamyl-alcohol dehydrogenase 5, cinnamyl-alcohol dehydrogenase 1, and chorismate mutase, were repressed in peach fruit at 0 degrees C as compared to that at 5 degrees C. The abundance of glucose-6-phosphate dehydrogenase, NADP-dependent isocitrate dehydrogenase, and NADP-dependent malic enzyme, which catalyze the reactions during sugar metabolism and energy pathways, was found to decrease in peach fruit stored at 0 degrees C. In addition, our data revealed that low temperature of 0 degrees C might regulate the endogenous H(2)O(2) level, resulting in activating the transcriptional level of genes encoding the proteins related to membrane stability. These results provide a comprehensive knowledge to understand the mechanisms by which peach fruit stored at 0 degrees C showed a higher chilling tolerance than that at 5 degrees C.
Relative Stability of Boiling of FC—72 and HFE—7100 with Applications to Electronic Device Cooling
Z.W.LIU; X.F.PENG; 等
2000-01-01
This paper investigates the relative stability between nucleate and film boiling modes of FC-72 and HFE-7100,which have potential to electronic device cooling applications.Equilibrium heat flux,qc.which refers to as an index for measuring the relative stability of boiling.Was obtained at a liquid subcooling of 0-20 K.Experimental results reveal that(1) qc increases with liquid subcooling;(2) although the FC-72 exhibits a higher critical heat flux(CHF) than does the HFE-7100,somewhat unexpectedly,the equilibrium heat flux for the latter is greater than the former,Rstated,at a prescribed heat flux,the risk to burnout for boiling of FC-72 is higher than that of HFE-7100,The shift in boiling curves interprets the experimental findings.
Bo You; Jun Yang; Guo-ping Yong; Shao-min Liu; Wei Xie; Qing-de Su
2011-01-01
Various ordered mesoporous carbons (OMCs) have been prepared by evaporation-induced triconstituent co-assembly method. Their mesostructural stability under different carbon content, aging time and acidity were conveniently monitored by X-ray diffraction, transmission electron microscopy, and N2 sorption isotherms techniques. The results show mesostructural stability of OMCs is enhanced as the carbon content increases from 36% to 46%, further increasing carbon content deteriorates the mesostructural stability. Increasing aging time from 0.5 h to 5.0 h make themesostructural stability go through an optimum 2.0 h) and gradually reduce framework shrinkage of the OMCs. Highly OMCs can only be obtained in the acidity range of 0.2-1.2 mol/L HC1, when the acidity is near the isoelectric point of silica, the resulting OMCs have the best mesostructure stability. Under the optimum condition, the carbon content of 46%, aging time of 2.0 h, and 0.2 mol/L HC1, the resulting OMCs have the best mesostructure stability and the highest BET urface areas of 2281 m2/g.
Fuhrman, David R.; Bingham, Harry B.; Madsen, Per A.
2004-01-01
This paper considers a method of lines stability analysis for finite difference discretizations of a recently published Boussinesq method for the study of highly non-linear and extremely dispersive water waves. The analysis demonstrates the near-equivalence of classical linear Fourier (von Neumann...
Arendse, CJ
2009-01-01
Full Text Available The material properties of hydrogenated amorphous silicon (a-Si:H) have been known to change when exposed to elevated temperatures. In this work researchers report on the thermal stability of the optical band gap and structural disorder in hot...
Arshad, M.; Seadawy, Aly R.; Lu, Dianchen
2017-08-01
The higher-order nonlinear Schrödinger equation (NLSE) with fourth-order dispersion, cubic-quintic terms, self-steepening and nonlinear dispersive terms describes the propagation of extremely short pulses in optical fibers. In this paper, the elliptic function, bright and dark solitons and solitary wave solutions of higher-order NLSE are constructed by employing a modified extended direct algebraic method, which has important applications in applied mathematics and physics. Furthermore, we also present the formation conditions of the bright and dark solitons for this equation. The modulation instability is utilized to discuss the stability of these solutions, which shows that all solutions are exact and stable. Many other higher-order nonlinear evolution equations arising in applied sciences can also be solved by this powerful, effective and reliable method.
Florian Hartig
Full Text Available If two species exhibit different nonlinear responses to a single shared resource, and if each species modifies the resource dynamics such that this favors its competitor, they may stably coexist. This coexistence mechanism, known as relative nonlinearity of competition, is well understood theoretically, but less is known about its evolutionary properties and its prevalence in real communities. We address this challenge by using adaptive dynamics theory and individual-based simulations to compare community stabilization and evolutionary stability of species that coexist by relative nonlinearity. In our analysis, evolution operates on the species' density-compensation strategies, and we consider a trade-off between population growth rates at high and low resource availability. We confirm previous findings that, irrespective of the particular model of density dependence, there are many combinations of overcompensating and undercompensating density-compensation strategies that allow stable coexistence by relative nonlinearity. However, our analysis also shows that most of these strategy combinations are not evolutionarily stable and will be outcompeted by an intermediate density-compensation strategy. Only very specific trade-offs lead to evolutionarily stable coexistence by relative nonlinearity. As we find no reason why these particular trade-offs should be common in nature, we conclude that the sympatric evolution and evolutionary stability of relative nonlinearity, while possible in principle, seems rather unlikely. We speculate that this may, at least in part, explain why empirical demonstrations of this coexistence mechanism are rare, noting, however, that the difficulty to detect relative nonlinearity in the field is an equally likely explanation for the current lack of empirical observations, and that our results are limited to communities with non-overlapping generations and constant resource supply. Our study highlights the need for
Hartig, Florian; Münkemüller, Tamara; Johst, Karin; Dieckmann, Ulf
2014-01-01
If two species exhibit different nonlinear responses to a single shared resource, and if each species modifies the resource dynamics such that this favors its competitor, they may stably coexist. This coexistence mechanism, known as relative nonlinearity of competition, is well understood theoretically, but less is known about its evolutionary properties and its prevalence in real communities. We address this challenge by using adaptive dynamics theory and individual-based simulations to compare community stabilization and evolutionary stability of species that coexist by relative nonlinearity. In our analysis, evolution operates on the species' density-compensation strategies, and we consider a trade-off between population growth rates at high and low resource availability. We confirm previous findings that, irrespective of the particular model of density dependence, there are many combinations of overcompensating and undercompensating density-compensation strategies that allow stable coexistence by relative nonlinearity. However, our analysis also shows that most of these strategy combinations are not evolutionarily stable and will be outcompeted by an intermediate density-compensation strategy. Only very specific trade-offs lead to evolutionarily stable coexistence by relative nonlinearity. As we find no reason why these particular trade-offs should be common in nature, we conclude that the sympatric evolution and evolutionary stability of relative nonlinearity, while possible in principle, seems rather unlikely. We speculate that this may, at least in part, explain why empirical demonstrations of this coexistence mechanism are rare, noting, however, that the difficulty to detect relative nonlinearity in the field is an equally likely explanation for the current lack of empirical observations, and that our results are limited to communities with non-overlapping generations and constant resource supply. Our study highlights the need for combining ecological and
A validated stability-indicating RP-HPLC assay method for Amsacrine and its related substances.
Devi, M Lalitha; Chandrasekhar, K B; Surendranath, K V; Rao, B M; Narayana, M B V
2011-08-01
A validated specific stability indicating reversed-phase high-performance liquid chromatography method was developed for the quantitative determination of Amsacrine as well as its related substances determination in bulk samples, in presence of degradation products, and its process related impurities. Forced degradation studies were performed on bulk samples of Amsacrine as per International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human use (ICH) prescribed stress conditions using acid, base, oxidative, thermal stress, and photolytic degradation to show the stability indicating power of the method. Significant degradation was observed during basic hydrolysis, slight degradation was observed in oxidative and thermal stress, and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies and the impurity spiked solution. Good resolution between the peaks corresponds to process-related impurities and degradation products from the analyte were achieved on Inertsil ODS column using the mobile phase consists a mixture of 1.0% triethyl amine in 20 mM potassium dihydrogen orthophosphate, with pH adjusted to 6.5, with ortho phosphoric acid in water and acetonitrile using a simple linear gradient. The detection was carried out at wavelength 248 nm. The mass balance in each case was in between 99.4% to 99.9%, indicating that the developed method was stability-indicating. Validation of the developed method was carried out as per ICH requirements. The developed method was found to be suitable to check the quality of bulk samples of Amsacrine at the time of batch release and also during its stability studies.
Clara Smal
Full Text Available BACKGROUND: Self-assembly is a common theme in proteins of unrelated sequences or functions. The human papillomavirus E7 oncoprotein is an extended dimer with an intrinsically disordered domain, that can form large spherical oligomers. These are the major species in the cytosol of HPV transformed and cancerous cells. E7 binds to a large number of targets, some of which lead to cell transformation. Thus, the assembly process not only is of biological relevance, but represents a model system to investigate a widely distributed mechanism. METHODOLOGY/PRINCIPAL FINDINGS: Using various techniques, we monitored changes in secondary, tertiary and quaternary structure in a time course manner. By applying a robust kinetic model developed by Zlotnik, we determined the slow formation of a monomeric "Z-nucleus" after zinc removal, followed by an elongation phase consisting of sequential second-order events whereby one monomer is added at a time. This elongation process takes place at a strikingly slow overall average rate of one monomer added every 28 seconds at 20 µM protein concentration, strongly suggesting either a rearrangement of the growing complex after binding of each monomer or the existence of a "conformation editing" mechanism through which the monomer binds and releases until the appropriate conformation is adopted. The oligomerization determinant lies within its small 5 kDa C-terminal globular domain and, remarkably, the E7 N-terminal intrinsically disordered domain stabilizes the oligomer, preventing an insoluble amyloid route. CONCLUSION: We described a controlled ordered mechanism with features in common with soluble amyloid precursors, chaperones, and other spherical oligomers, thus sharing determining factors for symmetry, size and shape. In addition, such a controlled and discrete polymerization reaction provides a valuable tool for nanotechnological applications. Finally, its increased immunogenicity related to its supramolecular
Lund, Rikke; Modvig, J; Due, P
2000-01-01
In a follow-up study of 70-95 years old women and men (n = 911) we studied the association between change and stability in three structural aspects of social relations (contact frequency, contact diversity, cohabitation status) from 1986-1990 and mortality after the next four years in 1994. Women.......02-14.94) and ORdiv: 6.04 (1.30-28.03). In summary, we found rather larger age differences in the strength of the association between change in structural social relations and mortality. Furthermore, the associations seemed stronger among women than men, which may however mainly be explained by the small number...
Park, S. H.; Lee, T. D.; Kong, S. H.; Yoon, S. Y.; Lee, H. S.; Kim, H. J.; Oh, H. S.
2008-04-01
Thermal stability of the present CoCrPt -SiO2 media becomes a more critical issue as recording density steadily increases. In the present study, thermal stability of the stacked media composed of high Ku CoPt -TiO2 and normal Ku CoCrPt -SiO2 was studied by changing stacking order and thickness of each layer while keeping a constant total thickness. When the CoPt -TiO2 layer was placed under the CoCrPt -SiO2 layer, negative nucleation field and coercivity increased much more than those of the reverse stacking case. Thermal stability of the CoPt -TiO2 bottom group was superior to that of the CoCrPt -SiO2 bottom group when measured by a spin stand.
Globalization by the Souths. Chinese-African Relations and International Order
Julien Rajaoson
2014-11-01
Full Text Available This study focuses on worldwide governance. It will be related to the Assian approach of international relationships. This approach claiming by the Chinese is closed to the David Miller Nationalist and liberal way of thinking. But it remains very restrictive because it is only based on the liberal economic point of view. We will do a critical study of the principles which are regulating the governances and we will analyse a special sectorial field: the Sino-African relations. These thoughts and statements need to have a sectorial dimension of approaching matters. The management of the different governments can have effects on local realities of people's life and on investments. In thirty years China passed from an emerging country to the second worldwide economically powerful country just behind the United States. Now, they must have an interdependance relationship with the United States. It is very important and necessary to undermine this interdependance relationship in order to understand how its economic strategy has an influence upon the worldwide market. And from this study, we will understand how the Chinese relate to the balance of power they are dealing with.
European Security through EU-Russian Relations: Towards a New Multilateral Order?
Sandra Fernandes
2011-05-01
Full Text Available Since the end of the Cold War, the EU and Russia have managed to create an original framework for institutionalised cooperation despite asymmetric characteristics. Yet, the way these two main security actors interact has an impact on the (non-resolution of security issues in Europe, ranging from ‘‘frozen conflicts’’ to the discussion of the security architecture. Since the second mandate of President Putin, the relation has been characterised by two paradoxical features. On the one hand, the methodology and the domains of cooperation have reached a high degree of achievement. On the other hand, the political quality of the relationship has deteriorated and it is not able to achieve the desired ‘‘strategic partnership’’ that should be based on a common set of values and principles. This article aims to define multilateralism as a paradigm applicable to EU-Russian relations. It examines their relationship in the security and defence realm and the Union’s reactions to a new security approach by Russia since the 2008 Medvedev proposal. The article questions how the EU-Russian political dialogue impacts on multilateralism in the security field. The conclusion considers EU-Russian relations as a peculiar multilateral playground addressing common security challenges, which still needs to be developed further in order to be instrumental in the search for collective and legitimate solutions.
Bercy, Anthony; Stefani, Fabio; Lopez, Olivier; Chardonnet, Christian; Pottie, Paul-Eric; Amy-Klein, Anne
2014-12-01
By using two-way frequency transfer, we implement a real-time frequency comparison over a uni-directional telecommunication network of 100 km using a pair of parallel fibers with simultaneous digital data transfer. The relative frequency stability is 10-15 at 1-s integration time and reaches 2 ×10-17 at 40 000 s, three orders of magnitude below the one-way fiber instability. We also demonstrate ultrahigh-resolution comparison of optical frequencies with a bidirectional scheme using a single fiber. We show that the relative stability at 1-s integration time is 7 ×10-18 and scales down to 5 ×10-21 . The same level of performance is reached when an optical link is implemented with an active compensation of the fiber noise. The fractional uncertainty of the frequency comparisons was evaluated for the best case to 2 ×10-20 . These results open the way to accurate and high-resolution frequency comparison of optical clocks over intercontinental fiber networks.
Film Grain-Size Related Long-Term Stability of Inverted Perovskite Solar Cells.
Chiang, Chien-Hung; Wu, Chun-Guey
2016-09-22
The power conversion efficiency (PCE) of the perovskite solar cell is high enough to be commercially viable. The next important issue is the stability of the device. This article discusses the effect of the perovskite grain-size on the long-term stability of inverted perovskite solar cells. Perovskite films composed of various sizes of grains were prepared by controlling the solvent annealing time. The grain-size related stability of the inverted cells was investigated both in ambient atmosphere at relative humidity of approximately 30-40 % and in a nitrogen filled glove box (H2 Osolar cell based on a perovskite film having the grain size larger than 1 μm (D-10) decreases less than 10 % with storage in a glove box and less than 15 % when it was stored under an ambient atmosphere for 30 days. However, the cell using the perovskite film composed of small (∼100 nm) perovskite grains (D-0) exhibits complete loss of PCE after storage under the ambient atmosphere for only 15 days and a PCE loss of up to 70 % with storage in the glove box for 30 days. These results suggest that, even under H2 O-free conditions, the chemical- and thermal-induced production of pin holes at the grain boundaries of the perovskite film could be the reason for long-term instability of inverted perovskite solar cells.
Frequency-domain generelaized singular peruturbation method for relative error model order reduction
Hamid Reza SHAKER
2009-01-01
A new mixed method for relative error model order reduction is proposed.In the proposed method the frequency domain balanced stochastic truncation method is improved by applying the generalized singular perturbation method to the frequency domain balanced system in the reduction procedure.The frequency domain balanced stochastic truncation method,which was proposed in [15] and [17] by the author,is based on two recently developed methods,namely frequency domain balanced truncation within a desired frequency bound and inner-outer factorization techniques.The proposed method in this paper is a carry over of the frequency-domain balanced stochastic truncation and is of interest for practical model order reduction because in this context it shows to keep the accuracy of the approximation as high as possible without sacrificing the computational efficiency and important system properties.It is shown that some important properties of the frequency domain stochastic balanced reduction technique are extended to the proposed reduction method by using the concept and properties of the reciprocal systems.Numerical results show the accuracy,simplicity and flexibility enhancement of the method.
Estimating the Relative Order of Speciation or Coalescence Events on a Given Phylogeny
Rutger Vos
2006-01-01
Full Text Available The reconstruction of large phylogenetic trees from data that violates clocklike evolution (or as a supertree constructed from any m input trees raises a difficult question for biologists– how can one assign relative dates to the vertices of the tree? In this paper we investigate this problem, assuming a uniform distribution on the order of the inner vertices of the tree (which includes, but is more general than, the popular Yule distribution on trees. We derive fast algorithms for computing the probability that (i any given vertex in the tree was the j–th speciation event (for each j, and (ii any one given vertex is earlier in the tree than a second given vertex. We show how the first algorithm can be used to calculate the expected length of any given interior edge in any given tree that has been generated under either a constant- rate speciation model, or the coalescent model.
Financial Brownian Particle in the Layered Order-Book Fluid and Fluctuation-Dissipation Relations
Yura, Yoshihiro; Takayasu, Hideki; Sornette, Didier; Takayasu, Misako
2014-03-01
We introduce a novel description of the dynamics of the order book of financial markets as that of an effective colloidal Brownian particle embedded in fluid particles. The analysis of comprehensive market data enables us to identify all motions of the fluid particles. Correlations between the motions of the Brownian particle and its surrounding fluid particles reflect specific layering interactions; in the inner layer the correlation is strong and with short memory, while in the outer layer it is weaker and with long memory. By interpreting and estimating the contribution from the outer layer as a drag resistance, we demonstrate the validity of the fluctuation-dissipation relation in this nonmaterial Brownian motion process.
Du, Yigang; Fan, Rui; Li, Yong
2016-01-01
An ultrasound imaging framework modeled with the first order nonlinear pressure–velocity relations (NPVR) based simulation and implemented by a half-time staggered solution and pseudospectral method is presented in this paper. The framework is capable of simulating linear and nonlinear ultrasound...... propagation and reflections in a heterogeneous medium with different sound speeds and densities. It can be initialized with arbitrary focus, excitation and apodization for multiple individual channels in both 2D and 3D spatial fields. The simulated channel data can be generated using this framework......, and ultrasound image can be obtained by beamforming the simulated channel data. Various results simulated by different algorithms are illustrated for comparisons. The root mean square (RMS) errors for each compared pulses are calculated. The linear propagation is validated by an angular spectrum approach (ASA...
B.Li; S.Inagaki; C.Miyazaki; H.Takahashi
2000-01-01
The FSM-16, MCM-41 and SBA-15 type hexagonal mesoporous silica materials having a highly arrange in order of the 2-dimensional structure were synthesized by using different silicon sources and surfactants. In the 2-dimensional silicate framework, pore size can be uniformly controlled by the combined use of the surfactants having different alkyl chains length and swelling agents (triisopropyl benzene). Pore-diameter of FSM-16 and MCM-41 can be expanded to 100 A, SBA-15 is 150 A. Crystal regularity decreased with increasing the pore-diameter in the FSM-16 derived from Kanemite (silicon source) and MCM-41 from water glass, its anionic char-acteristics on the pore wall may be higher than SBA-15 derived from oligomeric tetramethoxysilane (TMOS) is also reported. We have successfully used FSM-16 and MCM-41 as immobilizing agents of enzyme having cationic residues under isoelectric point. The level of adsorption of enzymes in the FSM-16 and MCM-41 was relatively high, but was low in the SBA-15 support. The mechanism of enzyme adsorption in mesopore was suggested to be the ionic interactions. In aqueous solutions, horseradish peroxidase (HRP) immobilized in FSM-16 containing 89A mesopore showed the highest loaded amounts(183mg/mg FSM),then a FSM-16 of pore-diameter 30 A only loaded a litter amounts (28mg/mg FSM) on the outside surface. The catalytic activity in organic solvent is high when HRP was immobilized in FSM-16 and MCM-41, but is low in case of SBA- 15.
无
2002-01-01
FSM-16, MCM-41 and SBA-15 types of hexagonal mesoporous silica with a highly ordered 2-dimensional structure were synthesized by using different silicon sources and surfactants. In the 2-dimensional silicate framework, pore size can be uniformly controlled by the combined use of the surfactants having different alkyl chain lengths and the swelling agents(triisopropyl benzene). The pore-diameter of FSM-16 and MCM-41 can be expanded to be 10 nm, SBA-15 to be 15 nm. The crystal regularity was decreased with the increase of the porediameter. In FSM-16 derived from kanemite (silicon source) and MCM-41 from water glass, their anionic characteristics on the pore-wall may be stronger than those of SBA-15 derived from oligomeric tetramethoxysilane(TMOS). We have successfully used FSM-16 and MCM-41 to immobilize the enzyme having cationic residues below isoelectric point. The level of adsorption of enzymes in FSM-16 and MCM-41 was relatively high, but was low in SBA-15 support. The mechanism of enzyme to be adsorbed in mesoporous silica was suggested to be the ionic interactions. In aqueous solutions, horseradish peroxidase(HTP) was immobilized in FSM-16 with 8. 9 nm mesopores and the highest loading amount (183 mg/mg FSM) was obtained, but for the FSM-16 of pore diameter 30 nm only an amount of 28 mg/mg FSM was obtained. The catalytic activity in the organic solvent was high when HRP was immobilized in FSM-16 and MCM-41, but it was low in case of SBA-15.
2014-03-01
simulation. Physica D 240, 841–858. Clayton, J., McDowell, D., 2004. Homogenized finite elastoplasticity and damage : theory and computations. Mech... damaged solids), the onset of material instability depends on strain, but in linear elastic solids, material stability is independent of strain and simply... damage in polycrystals. Theor. Appl. Fract. Mech. 45, 163–185. Clayton, J., 2008. A model for deformation and fragmentation in crushable brittle solids
La Torre, A; Giupponi, G; Duffy, D M; Pompili, M; Grözinger, M; Kapfhammer, H P; Conca, A
2014-01-01
Sexual dysfunction is a potential side effect of mood stabilizers and anxiolytic drugs: this article presents a critical review of the current literature. Although many studies have been published on sexual side effects of psychopharmacological treatment, only a minority relate to mood stabilizers and anxiolytic drugs. Most of these studies are not methodologically robust, few are RCTs and most did not use a validated rating scale to evaluate sexual functioning. In addition, many of the studies on sexual dysfunction associated with mood stabilizers and anxiolytic drugs are limited by other methodological flaws. While there is evidence to suggest that mood stabilizers, with some exceptions, negatively affect sexual functioning, there is still insufficient evidence to draw any clear conclusions about the effects of anxiolytic drugs on sexual function. There is some weak evidence to indicate that switching from enzyme-inducing to non-enzyme-inducing anticonvulsant drugs, could be clinically useful. Some researchers recommend that sexual dysfunction in patients taking antiepileptic drugs should in general be treated according to standard guidelines for the management of sexual dysfunction, since reliable data on special populations is not available. However, specific approaches may be useful, but cannot yet be recommended until further validating research has been conducted. We did not find evidence supporting the use of any specific treatment strategy for sexual dysfunction associated with anxiolytic treatment. This study was conducted in 2013 using the paper and electronic resources of the library of the Azienda Provinciale per i Servizi Sanitari (APSS) in Trento, Italy (http://atoz.ebsco.com/Titles/2793). The library has access to a wide range of databases including DYNAMED, MEDLINE Full Text, CINAHL Plus Full Text, The Cochrane Library, Micromedex healthcare series, BMJ Clinical Evidence. The full list of available journals can be viewed at http
Chawla, Mohit
2013-10-10
The G:C reverse Watson-Crick (W:W trans) base pair, also known as Levitt base pair in the context of tRNAs, is a structurally and functionally important base pair that contributes to tertiary interactions joining distant domains in functional RNA molecules and also participates in metabolite binding in riboswitches. We previously indicated that the isolated G:C W:W trans base pair is a rather unstable geometry, and that dicationic metal binding to the Guanine base or posttranscriptional modification of the Guanine can increase its stability. Herein, we extend our survey and report on other H-bonding interactions that can increase the stability of this base pair. To this aim, we performed a bioinformatics search of the PDB to locate all the occurencies of G:C trans base pairs. Interestingly, 66% of the G:C trans base pairs in the PDB are engaged in additional H-bonding interactions with other bases, the RNA backbone or structured water molecules. High level quantum mechanical calculations on a data set of representative crystal structures were performed to shed light on the structural stability and energetics of the various crystallographic motifs. This analysis was extended to the binding of the preQ1 metabolite to a preQ1-II riboswitch. 2013 The Author(s).
The relation between temporal and spatial stability in three-dimensional flows
Nayfeh, A. H.; Padhye, A.
1978-01-01
An analysis is presented of the nonparallel spatial or temporal stability of three-dimensional incompressible, isothermal boundary-layer flows taking into account the transverse velocity component as well as the axial and crossflow variations of the mean flow. The method of multiple scales is used to derive partial differential equations that describe the axial and crossflow variations of the disturbance amplitude, phase and wavenumbers. This equation is used to derive the expressions that relate the temporal and spatial instabilities. These relations are functions of the complex group velocities. Moreover, this equation is used to derive the expression that relates the spatial amplification in any direction to a calculated amplification in any other direction. These relations are verified by numerical results obtained for two- and three-dimensional disturbances in two- and three-dimensional flows.
Kalliopi K Patapati
Full Text Available Conventional wisdom has it that the presence of disordered regions in the three-dimensional structures of polypeptides not only does not contribute significantly to the thermodynamic stability of their folded state, but, on the contrary, that the presence of disorder leads to a decrease of the corresponding proteins' stability. We have performed extensive 3.4 µs long folding simulations (in explicit solvent and with full electrostatics of an undecamer peptide of experimentally known helical structure, both with and without its disordered (four residue long C-terminal tail. Our simulations clearly indicate that the presence of the apparently disordered (in structural terms C-terminal tail, increases the thermodynamic stability of the peptide's folded (helical state. These results show that at least for the case of relatively short peptides, the interplay between thermodynamic stability and the apparent structural stability can be rather subtle, with even disordered regions contributing significantly to the stability of the folded state. Our results have clear implications for the understanding of peptide energetics and the design of foldable peptides.
Stability and relative validity of the Neuromuscular Disease Impact Profile (NMDIP).
Bos, Isaäc; Kuks, Jan B M; Almansa, Josué; Kremer, Hubertus P H; Wynia, Klaske
2017-05-11
The aim of this study was to examine the stability and relative validity (RV) of the Neuromuscular Disease Impact Profile (NMDIP) using criterion-related groups. In a previous study the NMDIP-scales showed good internal consistency, convergent and discriminant validity. Known-groups analysis showed that the NMDIP discriminates between categories of extent of limitations. A cross-sectional postal survey study was performed on patients diagnosed with a NMD and registered at the Department of Neurology, University Medical Center Groningen, the Netherlands. Participants were asked to complete the preliminary NMDIP, the Medical Outcome study Short Form Questionnaire (SF-36), the World Health Organization Quality Of Life-abbreviation version (WHOQOL-bref), and two generic domain specific measures: the Groningen Activity Restriction Scale (GARS) and the Impact on Participation and Autonomy Questionnaire (IPAQ). The variables 'Extent of Limitations' and 'Quality of Life' were used to create criterion-related groups. Stability over time was tested using the Wilcoxon Signed Rank Test for paired samples and the intraclass correlation coefficients for repeated measures. RV was examined by comparing the ability of NMDIP with generic multidimensional health impact measures, and domain specific measures in discriminating between criterion-related subgroups using the Kruskal-Wallis H-test. Response rate was 70% (n = 702). The NMDIP-scales showed sufficient stability over time, and satisfactory or strong RV. In general, the NMDIP scales performed as well as or better than the concurrent measurement instruments. The NMDIP proved to be a valid and reliable disease-targeted measure with a broad scope on physical, psychological and social functioning.
Misra, Avijit; Biswas, Anindya; Pati, Arun K; Sen De, Aditi; Sen, Ujjwal
2015-05-01
Quantum discord is a measure of quantum correlations beyond the entanglement-separability paradigm. It is conceptualized by using the von Neumann entropy as a measure of disorder. We introduce a class of quantum correlation measures as differences between total and classical correlations, in a shared quantum state, in terms of the sandwiched relative Rényi and Tsallis entropies. We compare our results with those obtained by using the traditional relative entropies. We find that the measures satisfy all the plausible axioms for quantum correlations. We evaluate the measures for shared pure as well as paradigmatic classes of mixed states. We show that the measures can faithfully detect the quantum critical point in the transverse quantum Ising model and find that they can be used to remove an unquieting feature of nearest-neighbor quantum discord in this respect. Furthermore, the measures provide better finite-size scaling exponents of the quantum critical point than the ones for other known order parameters, including entanglement and information-theoretic measures of quantum correlations.
Morassi, Antonino; Vessella, Sergio
2010-01-01
We prove a sharp three sphere inequality for solutions to third order perturbations of a product of two second order elliptic operators with real coefficients. Then we derive various kinds of quantitative estimates of unique continuation for the anisotropic plate equation. Among these, we prove a stability estimate for the Cauchy problem for such an equation and we illustrate some applications to the size estimates of an unknown inclusion made of different material that might be present in the plate. The paper is self-contained and the Carleman estimate, from which the sharp three sphere inequality is derived, is proved in an elementary and direct way based on standard integration by parts.
Yan-quan Feng; Jin Ho Kwak; Ming-yao Xu
2003-01-01
Let X be a 4-valent connected vertex-transitive graph with odd-prime-power order pk (k ≥ 1)and let A be the full automorphism group of X. In this paper, we prove that the stabilizer Av of a vertex v in A is a 2-group ifp ≠ 5, or a {2,3}-group ifp = 5. Furthermore, ifp = 5 |Av| is not divisible by 32. As a result, we show that any 4-valent connected vertex-transitive graph with odd-prime-power order pk (k ≥ 1)is at most 1-arc-transitive for p ≠ 5 and 2-arc-transitive for p = 5.
Xiuling Liang
2016-12-01
Full Text Available The processing of causal relations has been constantly found to be asymmetrical once the roles of cause and effect are assigned to objects in interactions. We used a relationship recognition paradigm and recorded electroencephalographic (EEG signals to explore the neural mechanism underlying the asymmetrical representations of causal relations in semantic memory. The results revealed that the verification of causal relations is faster if two words appear in cause–effect order (e.g., virus-epidemic than if they appear in effect–cause order (e.g., epidemic-virus, whereas no such asymmetrical representation was found for the verification of hierarchical relations with reverse orders (e.g., bird-sparrow v. sparrow-bird in Experiment 1. Furthermore, the P2 amplitude elicited by superordinate-subordinate order was larger than that when in reverse order, whereas the N400 effect elicited by cause-effect order was smaller (more positive than when in reverse order. However, no such asymmetry, as well as P2 and N400 components, were observed when verifying the existence of a general associative relation in Experiment 2. We suggested that the smaller N400 in cause-effect order indicates their increased salience in semantic memory relative to the effect-cause order. These results provide evidence for dissociable neural processes, which are related to role binding, contributing to the generation of causal asymmetry.
Liang, Xiuling; Xiao, Feng; Wu, Lijun; Chen, Qingfei; Lei, Yi; Li, Hong
2016-01-01
The processing of causal relations has been constantly found to be asymmetrical once the roles of cause and effect are assigned to objects in interactions. We used a relationship recognition paradigm and recorded electroencephalographic (EEG) signals to explore the neural mechanism underlying the asymmetrical representations of causal relations in semantic memory. The results revealed that the verification of causal relations is faster if two words appear in "cause-effect" order (e.g., virus-epidemic) than if they appear in "effect-cause" order (e.g., epidemic-virus), whereas no such asymmetrical representation was found for the verification of hierarchical relations with reverse orders (e.g., bird-sparrow vs. sparrow-bird) in Experiment 1. Furthermore, the P2 amplitude elicited by "superordinate-subordinate" order was larger than that when in reverse order, whereas the N400 effect elicited by "cause-effect" order was smaller (more positive) than when in reverse order. However, no such asymmetry, as well as P2 and N400 components, were observed when verifying the existence of a general associative relation in Experiment 2. We suggested that the smaller N400 in cause-effect order indicates their increased salience in semantic memory relative to the effect-cause order. These results provide evidence for dissociable neural processes, which are related to role binding, contributing to the generation of causal asymmetry.
2013-02-21
... seq. \\2\\ Order Granting Exemptions from Certain Rules of Regulation SHO Related to Hurricane Sandy... Hurricane Sandy made landfall and whose settlement depends on the delivery of such physical certificates (or... COMMISSION Order Extending Temporary Exemptions From Certain Rules of Regulation SHO Related to...
Ali A. Ismail
2014-07-01
Full Text Available In this study a general form of recurrence relations of continuous function for doubly truncated modified Makeham distribution is obtained. Recurrence relations between single and product moments of order statistics from doubly truncated modified Makeham distribution are given. Also, a characterization of modified Makeham distribution from the right and the left is discussed through the properties of order statistics.
R.R. Perim
2011-07-01
Full Text Available During cardiopulmonary exercise testing (CPET, stroke volume can be indirectly assessed by O2 pulse profile. However, for a valid interpretation, the stability of this variable over time should be known. The objective was to analyze the stability of the O2 pulse curve relative to body mass in elite athletes. VO2, heart rate (HR, and relative O2 pulse were compared at every 10% of the running time in two maximal CPETs, from 2005 to 2010, of 49 soccer players. Maximal values of VO2 (63.4 ± 0.9 vs 63.5 ± 0.9 mL O2•kg-1•min-1, HR (190 ± 1 vs188 ± 1 bpm and relative O2 pulse (32.9 ± 0.6 vs 32.6 ± 0.6 mL O2•beat-1•kg-1 were similar for the two CPETs (P > 0.05, while the final treadmill velocity increased from 18.5 ± 0.9 to 18.9 ± 1.0 km/h (P < 0.01. Relative O2 pulse increased linearly and similarly in both evaluations (r² = 0.64 and 0.63 up to 90% of the running time. Between 90 and 100% of the running time, the values were less stable, with up to 50% of the players showing a tendency to a plateau in the relative O2 pulse. In young healthy men in good to excellent aerobic condition, the morphology of the relative O2 pulse curve is consistent up to close to the peak effort for a CPET repeated within a 1-year period. No increase in relative O2pulse at peak effort could represent a physiologic stroke volume limitation in these athletes.
Specht, Jule; Egloff, Boris; Schmukle, Stefan C
2011-10-01
Does personality change across the entire life course, and are those changes due to intrinsic maturation or major life experiences? This longitudinal study investigated changes in the mean levels and rank order of the Big Five personality traits in a heterogeneous sample of 14,718 Germans across all of adulthood. Latent change and latent moderated regression models provided 4 main findings: First, age had a complex curvilinear influence on mean levels of personality. Second, the rank-order stability of Emotional Stability, Extraversion, Openness, and Agreeableness all followed an inverted U-shaped function, reaching a peak between the ages of 40 and 60 and decreasing afterward, whereas Conscientiousness showed a continuously increasing rank-order stability across adulthood. Third, personality predicted the occurrence of several objective major life events (selection effects) and changed in reaction to experiencing these events (socialization effects), suggesting that personality can change due to factors other than intrinsic maturation. Fourth, when events were clustered according to their valence, as is commonly done, effects of the environment on changes in personality were either overlooked or overgeneralized. In sum, our analyses show that personality changes throughout the life span, but with more pronounced changes in young and old ages, and that this change is partly attributable to social demands and experiences.
Stability of Relative Equilibria in the Planar N-Vortex Problem
Roberts, Gareth E
2013-01-01
We study the linear and nonlinear stability of relative equilibria in the planar N-vortex problem, adapting the approach of Moeckel from the corresponding problem in celestial mechanics. After establishing some general theory, a topological approach is taken to show that for the case of positive circulations, a relative equilibrium is linearly stable if and only if it is a nondegenerate minimum of the Hamiltonian restricted to a level surface of the angular impulse (moment of inertia). Using a criterion of Dirichlet's, this implies that any linearly stable relative equilibrium with positive vorticities is also nonlinearly stable. Two symmetric families, the rhombus and the isosceles trapezoid, are analyzed in detail, with stable solutions found in each case.
Relative contributions of animal and muscle effects to variation in beef lean color stability.
King, D A; Shackelford, S D; Wheeler, T L
2011-05-01
Muscles from beef carcasses (n = 100) were selected from a commercial processor and aged for 14 d. Longissimus lumborum (LL), semimembranosus (SM), biceps femoris (BF), gluteus medius (GM), triceps brachii (TB), rectus femoris, vastus lateralis, adductor, semitendinosus, infraspinatus, teres major, biceps femoris ischiatic head, biceps femoris sirloin cap, and gracillus steaks were placed in display for 9 d. Instrumental color variables [lightness (L*), redness (a*), yellowness (b*), hue angle, chroma, and overall color change from d 0 (E)] were determined on d 0, 1, 3, 6, and 9 of display. Muscle pH and myoglobin content were determined for LL, SM, BF, GM, and TB. Muscles differed (P muscles. Relationships between color variables measured in LL steaks and those measured in steaks from other muscles differed across days of display with the strongest relationships being observed earlier in the display period for labile muscles and later in stable muscles. Lightness of LL steaks was correlated with lightness of all of other muscles evaluated, regardless of display day (r = 0.27 to 0.79). For a*, hue angle, chroma, and E values, the strongest relationships between LL values and those of other muscles were detected between d 9 LL values and those of other muscles on d 3, 6, or 9, depending on the relative stability of the muscle. Correlation coefficients between d 9 a*, hue angle, chroma, and E values in LL and those of other muscles were 0.50, 0.65, 0.28, and 0.43 (P muscles included in the study. Myoglobin content of SM, BF, GM, and TB was highly correlated with that of LL (r = 0.83, 0.82, 0.72, and 0.67, respectively; P Muscle pH of LL was correlated with pH of SM and GM (r = 0.44 and 0.53; P 0.05) pH of BF or TB. Muscle effects generally explained more variation in a*, b*, hue angle, chroma, and E than animal effects. However, the relative importance of animal effects increased as display continued. These data indicate that animal effects were consistent across
On the stability of Einstein static universe in doubly general relativity scenario
Khodadi, M., E-mail: m.khodadi@stu.umz.ac.ir [Department of Physics, Faculty of Basic Sciences, University of Mazandaran, P. O. Box 47416-95447, Babolsar (Iran, Islamic Republic of); Heydarzade, Y., E-mail: heydarzade@azaruniv.edu [Department of Physics, Azarbaijan Shahid Madani University, 53714-161, Tabriz (Iran, Islamic Republic of); Nozari, K., E-mail: knozari@umz.ac.ir [Department of Physics, Faculty of Basic Sciences, University of Mazandaran, P. O. Box 47416-95447, Babolsar (Iran, Islamic Republic of); Darabi, F., E-mail: f.darabi@azaruniv.edu [Department of Physics, Azarbaijan Shahid Madani University, 53714-161, Tabriz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), 55134-441, Maragha (Iran, Islamic Republic of)
2015-12-12
By presenting a relation between the average energy of the ensemble of probe photons and the energy density of the universe, in the context of gravity’s rainbow or the doubly general relativity scenario, we introduce a rainbow FRW universe model. By analyzing the fixed points in the flat FRW model modified by two well-known rainbow functions, we find that the finite time singularity avoidance (i.e. Big Bang) may still remain as a problem. Then we follow the “emergent universe” scenario in which there is no beginning of time and consequently there is no Big-Bang singularity. Moreover, we study the impact of high energy quantum gravity modifications related to the gravity’s rainbow on the stability conditions of an “Einstein static universe” (ESU). We find that independent of the particular rainbow function, the positive energy condition dictates a positive spatial curvature for the universe. In fact, without raising a nonphysical energy condition in the quantum gravity regimes, we can observe agreement between gravity’s rainbow scenario and the basic assumption of the modern version of the “emergent universe”. We show that in the absence and presence of an energy-dependent cosmological constant Λ(ϵ), a stable Einstein static solution is available versus the homogeneous and linear scalar perturbations under the variety of the obtained conditions. Also, we explore the stability of ESU against the vector and tensor perturbations.
Asymmetry of genetic variation in fitness-related traits: apparent stabilizing selection on g(max).
McGuigan, Katrina; Blows, Mark W
2009-11-01
The maintenance of genetic variation in traits closely associated with fitness remains a key unresolved issue in evolutionary genetics. One important qualification on the observation of genetic variation in fitness-related traits is that such traits respond asymmetrically to selection, evolving to a greater extent in the direction of lower fitness. Here we test the hypothesis that standing genetic variation in fitness-related traits is principally maintained for unfit phenotypes. Male Drosophila bunnanda vary in mating success (the primary determinant of male fitness) due to female mate choice. We used competitive mating success to partitioning males into two groups: successful (high fitness) and unsuccessful (low fitness). Relative to successful males, unsuccessful males harbored considerably greater levels of additive genetic variation for sexual signaling traits. This genetic asymmetry was detected for a multivariate trait that we demonstrated was not directly under stabilizing sexual selection, leading us to conclude the trait was under apparent stabilizing selection. Consequently, our results suggest genetic variance might be biased toward low fitness even for traits that are not themselves the direct targets of selection. Simple metrics of genetic variance are unlikely to be adequate descriptors of the complex nature of the genetic basis of traits under selection.
Ganesan, Sekar; Shieh, Leang S.; Mehio, Mohamad M.
1991-01-01
This paper considers the problem of optimal regulator design of linear multivariable systems with prescribed pole locations and/or poles corresponding to specified relative stability. A sequential method based on the frequency-domain optimality condition is proposed for achieving the desired pole assignment and determination of the corresponding quadratic performance index. This design method enables the retention of some stable open-loop poles and the associated eigenvectors in the closed-loop system. An illustrative example is provided to demonstrate the effectiveness of the proposed method.
Early Age-Related Functional Connectivity Decline in High-Order Cognitive Networks
Siman-Tov, Tali; Bosak, Noam; Sprecher, Elliot; Paz, Rotem; Eran, Ayelet; Aharon-Peretz, Judith; Kahn, Itamar
2017-01-01
As the world ages, it becomes urgent to unravel the mechanisms underlying brain aging and find ways of intervening with them. While for decades cognitive aging has been related to localized brain changes, growing attention is now being paid to alterations in distributed brain networks. Functional connectivity magnetic resonance imaging (fcMRI) has become a particularly useful tool to explore large-scale brain networks; yet, the temporal course of connectivity lifetime changes has not been established. Here, an extensive cross-sectional sample (21–85 years old, N = 887) from a public fcMRI database was used to characterize adult lifespan connectivity dynamics within and between seven brain networks: the default mode, salience, dorsal attention, fronto-parietal control, auditory, visual and motor networks. The entire cohort was divided into young (21–40 years, mean ± SD: 25.5 ± 4.8, n = 543); middle-aged (41–60 years, 50.6 ± 5.4, n = 238); and old (61 years and above, 69.0 ± 6.3, n = 106) subgroups. Correlation matrices as well as a mixed model analysis of covariance indicated that within high-order cognitive networks a considerable connectivity decline is already evident by middle adulthood. In contrast, a motor network shows increased connectivity in middle adulthood and a subsequent decline. Additionally, alterations in inter-network interactions are noticeable primarily in the transition between young and middle adulthood. These results provide evidence that aging-related neural changes start early in adult life. PMID:28119599
Li, Xi-Zeng; Su, Bao-Xia
1994-01-01
It is found that two-mode output quantum electromagnetic field in two-mode squeezed states exhibits higher-order squeezing to all even orders. And the generalized uncertainty relations are also presented for the first time. The concept of higher-order squeezing of the single-mode quantum electromagnetic field was first introduced and applied to several processes by Hong and Mandel in 1985. Lately Li Xizeng and Shan Ying have calculated the higher-order squeezing in the process of degenerate four-wave mixing and presented the higher-order uncertainty relations of the fields in single-mode squeezed states. In this paper we generalize the above work to the higher-order squeezing in two-mode squeezed states. The generalized uncertainty relations are also presented for the first time.
Ante Miličević
2011-01-01
Full Text Available Logarithms of stability constants, log K1 and log β2, of the first transition series metal mono- and bis-complexes with any of four aliphatic amino acids (glycine, alanine, valine and leucine decrease monotonously with third order valence connectivity index, 3χv, from Cu2+ to Mn2+. While stability of the complexes with the same metal is linearly dependent on 3χv, stability constants of Mn2+, Fe2+, Co2+, and Ni2+complexes with the same ligand show a quadratic dependence on 3χv. As Cu2+ complexes deviate significantly from quadratic functions, models for the simultaneous estimation of the stability constants, yielding r = 0.999 (S.E. = 0.05 and r = 0.998 (S.E. = 0.11, for log K1 and log β2, respectively, were developed only for Mn2+, Fe2+, Co2+, and Ni2+ complexes with amino acids.
On the Relative Stability of Cumulenone and Aldehyde Isomers: when we HEAT345(Q) Things UP
Lee, Kelvin; McCarthy, Michael C.; Stanton, John F.
2017-06-01
Isomers of H_2C_{2n+1}O are examples of complex organic molecules that are either known or proposed to exist in the interstellar medium. For the smallest of these chains (H_2C_3O) only two of three isomers are observed in space: propynal (HC(O)CCH) and cyclopropenone (c-C_3H_2O), while evidence for the remaining isomer propadienone (H_2C_3O) is currently lacking. Potentially, this behaviour may be rationalised by a thermodynamic argument: several studies have provided quantum chemical calculations in an effort to determine the relative thermodynamic stability between these three isomers. An early study by Radom, at the SCF/6-31G** level ranked HC(O)CCH as the thermodynamic minimum, followed by H_2C_3O, and c-C_3H_2O. The most recent determination by Karton and Talbi, using W2-F12 theory, places H_2C_3O as the lowest energy isomer; 2.5 kJ mol^{-1} lower than the HC(O)CCH form. In an attempt to resolve this long-standing ambiguity, we were motivated to provide high level calculations based on the HEAT protocol. In this talk, we will discuss the relative stability of H_2C_3O and H_2C_5O isomers, along with their sulfur analogues, as revealed by HEAT345(Q) theory.
Stability of titania nanotube arrays in aqueous environment and the related factors.
Cao, Can; Yan, Jun; Zhang, Yumei; Zhao, Lingzhou
2016-03-10
Titania nanotube arrays (NTAs) on titanium (Ti) fabricated by electrochemical anodization have attracted tremendous interest for diverse applications, of which most perform in aqueous environment or related to interaction with water. The NTAs are widely studied however the related factor of stability of NTAs when applied in such environment has rarely been concerned. We report that the annealed anatase NTAs are stable but the non-annealed amorphous NTAs are unstable to undergo specific structural change accompanied with a process of amorphous TiO2 dissolution and anatase TiO2 recrystallization. Quite unexpectedly, the non-annealed NTAs still show good stability without structural change in the cell culture media, possibly due to the presence of inorganics that may interfere with the TiO2 dissolution/redeposition process. The pH value of the aqueous environment is not a determinant factor for the structural change for non-annealed NTAs or not, while the temperature and the existence of F(-) can accelerate the structural change process. F(-) may play a very important role in the change process.
Stability of titania nanotube arrays in aqueous environment and the related factors
Cao, Can; Yan, Jun; Zhang, Yumei; Zhao, Lingzhou
2016-01-01
Titania nanotube arrays (NTAs) on titanium (Ti) fabricated by electrochemical anodization have attracted tremendous interest for diverse applications, of which most perform in aqueous environment or related to interaction with water. The NTAs are widely studied however the related factor of stability of NTAs when applied in such environment has rarely been concerned. We report that the annealed anatase NTAs are stable but the non-annealed amorphous NTAs are unstable to undergo specific structural change accompanied with a process of amorphous TiO2 dissolution and anatase TiO2 recrystallization. Quite unexpectedly, the non-annealed NTAs still show good stability without structural change in the cell culture media, possibly due to the presence of inorganics that may interfere with the TiO2 dissolution/redeposition process. The pH value of the aqueous environment is not a determinant factor for the structural change for non-annealed NTAs or not, while the temperature and the existence of F− can accelerate the structural change process. F− may play a very important role in the change process. PMID:26960922
On the relative importance of second-order terms in relativistic dissipative fluid dynamics
Molnár, E; Denicol, G S; Rischke, D H
2013-01-01
In Denicol et al., Phys. Rev. D 85, 114047 (2012), the equations of motion of relativistic dissipative fluid dynamics were derived from the relativistic Boltzmann equation. These equations contain a multitude of terms of second order in Knudsen number, in inverse Reynolds number, or their product. Terms of second order in Knudsen number give rise to non-hyperbolic (and thus acausal) behavior and must be neglected in (numerical) solutions of relativistic dissipative fluid dynamics. The coefficients of the terms which are of the order of the product of Knudsen and inverse Reynolds numbers have been explicitly computed in the above reference, in the limit of a massless Boltzmann gas. Terms of second order in inverse Reynolds number arise from the collision term in the Boltzmann equation, upon expansion to second order in deviations from the single-particle distribution function in local thermodynamical equilibrium. In this work, we compute these second-order terms for a massless Boltzmann gas with constant scatt...
Naibi Lakshminarayana, Arun
2015-01-01
Bisindeno-annulated pentacenes 3a and 3b were synthesized by a simple regio-selective, FeCl3-mediated Scholl reaction from the corresponding 6,13-diaryl pentacene precursors. The fusion of two indeno-units dramatically changes the electronic properties and chemical reactivity of pentacene and the obtained compounds exhibited exceptionally high photo-stability in the solution, with a half-life time of 11.2 (3a) and 32.0 (3b) days under ambient light and air conditions. Ordered molecular packing with a small π-π stacking distance was observed in the single crystals of 3a and 3b. Our research provides a promising strategy to access stable higher order acenes with controlled molecular order. This journal is
New Operator Ordering Formulas Related to Hermite Polynomials Derived by Virtue of IWOP Technique
FAN Hong-Yi
2004-01-01
By virtue of the technique of integration within an ordered product of operators and the fundamentaloperator identity Hn(X) = 2n : Xn :, where X is the coordinate operator and Hn is the n-order Hermite polynomials,:: is the normal ordering symbol, we not only simplify the derivation of the main properties of Hermite polynomials,but also directly derive some new operator identities regarding to Hn(X). Operation for transforming f(X) → :f(X) :is also discussed.
New Operator Ordering Formulas Related to Hermite Polynomials Derived by Virtue of IWOP Technique
FANHong-Yi
2004-01-01
By virtue of the technique of integration within an ordered product of operators and the fundamental operator identity Hn(X)=2n : Xn :, where X is the coordinate operator and Hn is the n-order Hermite polynomials,: : is the normal ordering symbol, we not only simplify the derivation of the main properties of Hermitc polynomials, but also directly derive some new operator identities regarding to Hn(X). Operation for transforming f(X) → : f(X) :is also discussed.
Yesuratnam, G.; Thukaram, D. [Department of Electrical Engineering, Indian Institute of Science, Bangalore 560012 (India)
2007-10-15
This paper presents an approach for alleviation of network over loads in the day-to-day operation of power systems under deregulated environment. The control used for over load alleviation is real power generation rescheduling based on relative electrical distance (RED) concept. The method estimates the relative location of load nodes with respect to the generator nodes. The contribution of each generator for a particular over loaded line is first identified, then based on RED concept the desired proportions of generations for the desired overload relieving is obtained, so that the system will have minimum transmission losses and more stability margins with respect to voltage profiles, bus angles and better transmission tariff. Results obtained for network overload alleviation of suitably modified IEEE 39-bus New England system are presented for illustration purposes. (author)
Teraoka, R; Otsuka, M; Matsuda, Y
1993-06-01
The chemical stability of ranitidine HCl in solution and in the solid state at various temperatures was investigated by high-performance liquid chromatography. Ranitidine HCl was unstable in lower pH buffer solutions, and the percent degradation after 72 h increased as the pH of the buffer solution was reduced. The percent degradation in the unbuffered solution increased dose dependently. The critical relative humidity (CRH) of the ranitidine HCl bulk powder was approximately 67% relative humidity (RH). The amount of water adsorbed onto the sample above the CRH was proportional to the RH level. The percent degradation of the powder below 50% RH was almost negligible because, at this level, it was a solid. The percent degradation at 60-70% RH was higher than that above 70% RH. Ranitidine HCl powder was unstable around the CRH.
Remarkable Stability of Charge Density Wave Order in La1.875 Ba0.125 CuO4
Chen, X. M.; Thampy, V.; Mazzoli, C.; Barbour, A. M.; Miao, H.; Gu, G. D.; Cao, Y.; Tranquada, J. M.; Dean, M. P. M.; Wilkins, S. B.
2016-10-01
The occurrence of charge-density-wave (CDW) order in underdoped cuprates is now well established, although the precise nature of the CDW and its relationship with superconductivity is not. Theoretical proposals include contrasting ideas such as that pairing may be driven by CDW fluctuations or that static CDWs may intertwine with a spatially modulated superconducting wave function. We test the dynamics of CDW order in La1.825 Ba0.125 CuO4 by using x-ray photon correlation spectroscopy at the CDW wave vector, detected resonantly at the Cu L3 edge. We find that the CDW domains are strikingly static, with no evidence of significant fluctuations up to 2 ¾ h . We discuss the implications of these results for some of the competing theories.
Remarkable Stability of Charge Density Wave Order in La_{1.875}Ba_{0.125}CuO_{4}.
Chen, X M; Thampy, V; Mazzoli, C; Barbour, A M; Miao, H; Gu, G D; Cao, Y; Tranquada, J M; Dean, M P M; Wilkins, S B
2016-10-14
The occurrence of charge-density-wave (CDW) order in underdoped cuprates is now well established, although the precise nature of the CDW and its relationship with superconductivity is not. Theoretical proposals include contrasting ideas such as that pairing may be driven by CDW fluctuations or that static CDWs may intertwine with a spatially modulated superconducting wave function. We test the dynamics of CDW order in La_{1.825}Ba_{0.125}CuO_{4} by using x-ray photon correlation spectroscopy at the CDW wave vector, detected resonantly at the Cu L_{3} edge. We find that the CDW domains are strikingly static, with no evidence of significant fluctuations up to 2 ¾ h. We discuss the implications of these results for some of the competing theories.
Nielsen, Peter; Bocewicz, G.
2012-01-01
in order to keep production lines within the cell working without any shortage of parts fed from feeders. A mixed-integer programming (MIP) model is developed to find the optimal solution for the problem. In the MIP formulation, a method based on the (s, Q) inventory system is applied to define time...... windows for multiple-part feeding tasks. A case study is implemented at an impeller production line in a factory to demonstrate the result of the proposed MIP model....
Stabilized High-order Galerkin Methods Based on a Parameter-free Dynamic SGS Model for LES
2015-01-01
and high-order discontinuous úNaval Postgraduate School, Dept. of Applied Mathematics . Monterey (CA) U.S.A. †smarras1@nps.edu ‡Uppsala University, Dept...NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School,Department of Applied Mathematics ,Monterey,CA,93943 8...in the aforementioned literature, this type of regularization is often the subject of criticism by physicists who, for the most part, doubt the
2011-07-26
Cottrell, and Bazilevs in [21], where NURBS were used as high-order basis functions, un- expected convergence to monotone results were obtained...methods by Canuto and coworkers in [17, 18, 19, 52], and later by Hughes and coworkers in [21] using non-uniform rational B-splines ( NURBS ). In this...Hughes, J. A. Cottrell, Y. Bazilevs, Isogeometric analysis: CAD, finite elements, NURBS , exact geometry and mesh refinement, Comput. Methods Appl
The improved 10th order QED expression for a_{\\mu} new results and related estimates
Kataev, A L
2006-01-01
New estimates of the 10th order QED corrections to the muon anomalous magnetic moment are presented. The estimates include the information on definite improved 10th order QED contributions to $a_{\\mu}$, calculated by Kinoshita and Nio. The final estimates are in good agreement with the ones, given recently by Kinoshita.
2012-04-24
... Boiling Water Reactor Licensees With Mark I and Mark II Containments: Order Modifying Licenses With Regard to Reliable Hardened Containment Vents (Effective Immediately) Docket No. Ea-12- 050 All Power... immediately effective order issued to all operating boiling water reactor licensees with Mark I and Mark...
Structure and stability insights into tumour suppressor p53 evolutionary related proteins.
Bruno Pagano
Full Text Available The p53 family of genes and their protein products, namely, p53, p63 and p73, have over one billion years of evolutionary history. Advances in computational biology and genomics are enabling studies of the complexities of the molecular evolution of p53 protein family to decipher the underpinnings of key biological conditions spanning from cancer through to various metabolic and developmental disorders and facilitate the design of personalised medicines. However, a complete understanding of the inherent nature of the thermodynamic and structural stability of the p53 protein family is still lacking. This is due, to a degree, to the lack of comprehensive structural information for a large number of homologous proteins and to an incomplete knowledge of the intrinsic factors responsible for their stability and how these might influence function. Here we investigate the thermal stability, secondary structure and folding properties of the DNA-binding domains (DBDs of a range of proteins from the p53 family using biophysical methods. While the N- and the C-terminal domains of the p53 family show sequence diversity and are normally targets for post-translational modifications and alternative splicing, the central DBD is highly conserved. Together with data obtained from Molecular Dynamics simulations in solution and with structure based homology modelling, our results provide further insights into the molecular properties of evolutionary related p53 proteins. We identify some marked structural differences within the p53 family, which could account for the divergence in biological functions as well as the subtleties manifested in the oligomerization properties of this family.
Wen, Xiao-Yong; Yan, Zhenya; Malomed, Boris A.
2016-12-01
An integrable system of two-component nonlinear Ablowitz-Ladik equations is used to construct complex rogue-wave (RW) solutions in an explicit form. First, the modulational instability of continuous waves is studied in the system. Then, new higher-order discrete two-component RW solutions of the system are found by means of a newly derived discrete version of a generalized Darboux transformation. Finally, the perturbed evolution of these RW states is explored in terms of systematic simulations, which demonstrates that tightly and loosely bound RWs are, respectively, nearly stable and strongly unstable solutions.
Wen, Xiao-Yong; Yan, Zhenya; Malomed, Boris A
2016-12-01
An integrable system of two-component nonlinear Ablowitz-Ladik equations is used to construct complex rogue-wave (RW) solutions in an explicit form. First, the modulational instability of continuous waves is studied in the system. Then, new higher-order discrete two-component RW solutions of the system are found by means of a newly derived discrete version of a generalized Darboux transformation. Finally, the perturbed evolution of these RW states is explored in terms of systematic simulations, which demonstrates that tightly and loosely bound RWs are, respectively, nearly stable and strongly unstable solutions.
Stability-indicating UPLC method for determining related substances and degradants in dronedarone.
Pydimarry, Surya Prakash Rao; Cholleti, Vijay Kumar; Vangala, Ranga Reddy
2014-08-01
A simple, sensitive and reproducible method was developed on ultra-performance liquid chromatography coupled with photodiode array detection for the quantitative determination of dronedarone hydrochloride (DRO) in drug substance and pharmaceutical dosage forms. The method is applicable for the quantification of related substances and assays of drug substances. Chromatographic separation was achieved on Acquity UPLC BEH C8 100 mm, 2.1 mm and 1.7 µm columns, using gradient elution within a short run time of 10.0 min. The eluted compounds were monitored at 288 nm, the flow rate was 0.5 mL/min and the column oven temperature was maintained at 40°C. The resolution of DRO and 11 impurities (potentials and by-products) was greater than 2.0 for all pairs of components. The high correlation coefficient value (>0.9995) indicates the clear correlations between the concentrations of investigated compound and their peak areas within the test ranges. The repeatability and intermediate precision, expressed by the relative standard deviation, were less than 2.5%. The accuracy and validity of the method were further ascertained by performing recovery studies via a spike method. The accuracy of the method, expressed as relative error, was satisfactory. No interference was observed from concomitant substances normally added to the tablets. DRO was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. DRO was found to degrade significantly in acid and base stress conditions and to remain stable in thermal, photolytic degradation, oxidative and hydrolytic conditions. The degradation products were well resolved from primary peak and its impurities, proving that the method is stability indicating. The developed method was validated as per International Conference on Harmonization guidelines with respect to specificity, limit of detection, limit of quantification, linearity, accuracy, precision, solution stability and robustness
On the stability of Einstein static universe in doubly general relativity scenario
Khodadi, M.; Nozari, K. [University of Mazandaran, Department of Physics, Faculty of Basic Sciences, Babolsar (Iran, Islamic Republic of); Heydarzade, Y. [Azarbaijan Shahid Madani University, Department of Physics, Tabriz (Iran, Islamic Republic of); Darabi, F. [Azarbaijan Shahid Madani University, Department of Physics, Tabriz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of)
2015-12-15
By presenting a relation between the average energy of the ensemble of probe photons and the energy density of the universe, in the context of gravity's rainbow or the doubly general relativity scenario, we introduce a rainbow FRW universe model. By analyzing the fixed points in the flat FRW model modified by two well-known rainbow functions, we find that the finite time singularity avoidance (i.e. Big Bang) may still remain as a problem. Then we follow the ''emergent universe'' scenario in which there is no beginning of time and consequently there is no Big-Bang singularity. Moreover, we study the impact of high energy quantum gravity modifications related to the gravity's rainbow on the stability conditions of an ''Einstein static universe'' (ESU). We find that independent of the particular rainbow function, the positive energy condition dictates a positive spatial curvature for the universe. In fact, without raising a nonphysical energy condition in the quantum gravity regimes, we can observe agreement between gravity's rainbow scenario and the basic assumption of the modern version of the ''emergent universe''. We show that in the absence and presence of an energy-dependent cosmological constant Λ(ε), a stable Einstein static solution is available versus the homogeneous and linear scalar perturbations under the variety of the obtained conditions. Also, we explore the stability of ESU against the vector and tensor perturbations. (orig.)
Gender Nonconformity and Birth Order in Relation to Anal Sex Role Among Gay Men.
Swift-Gallant, Ashlyn; Coome, Lindsay A; Monks, D Ashley; VanderLaan, Doug P
2017-04-04
Androphilia is associated with an elevated number of older brothers among natal males. This association, termed the fraternal birth order effect, has been observed among gay men who exhibit marked gender nonconformity. Gender nonconformity has been linked to gay men's preferred anal sex role. The present study investigated whether these two lines of research intersect by addressing whether the fraternal birth order effect was associated with both gender nonconformity and a receptive anal sex role (243 gay men, 91 heterosexual men). Consistent with previous research, we identified the fraternal birth order effect in our sample of gay men. Also, gay men were significantly more gender-nonconforming on adulthood and recalled childhood measures compared to heterosexual men. When gay men were compared based on anal sex role (i.e., top, versatile, bottom), all groups showed significantly greater recalled childhood and adult male gender nonconformity than heterosexual men, but bottoms were most nonconforming. Only gay men with a bottom anal sex role showed evidence of a fraternal birth order effect. A sororal birth order effect was found in our sample of gay men, driven by versatiles. No significant associations were found between fraternal birth order and gender nonconformity measures. These results suggest that the fraternal birth order effect may apply to a subset of gay men who have a bottom anal sex role preference and that this subgroup is more gender-nonconforming. However, there were no significant associations between fraternal birth order and gender nonconformity at the individual level. As such, based on the present study, whether processes underpinning the fraternal birth order effect influence gender nonconformity is equivocal.
Li, Xi-Zeng; Su, Bao-Xia
1996-01-01
It is found that the field of the combined mode of the probe wave and the phase-conjugate wave in the process of non-degenerate four-wave mixing exhibits higher-order squeezing to all even orders. And the generalized uncertainty relations in this process are also presented.
Kasa, Srinivasulu; Raja Sekhar Reddy, M; Kadaboina, Raja Sekhar; Murki, Veerender; Mulukutla, Venkata Suryanarayana
2014-08-01
A novel, simple, sensitive and stability-indicating high-performance liquid chromatography method was developed and validated for the quantification of impurities (process related and degradants) and the assay determination of Bendamustine hydrochloride. A chromatographic separation of Bendamustine and its impurities was achieved with an Inertsil ODS-2 analytical column, 250 × 4.6 mm, 5 µm, using gradient elution with mobile phase A consisting of a mixture of water and trifluoroacetic acid (1000:1, v/v) and mobile phase B consisting of acetonitrile. The instrumental settings included a flow rate of 1.0 mL/min, column temperature of 27°C and a detector wavelength of 233 nm, using a photodiode array detector. The tailing factor for Bendamustine was 1.10. Bendamustine hydrochloride was exposed to thermal, photolytic, hydrolytic and oxidative stress conditions and the stressed samples were analyzed by the proposed method. Peak homogeneity data of Bendamustine were obtained by using a photodiode array detector in the stressed sample chromatograms, which demonstrated the specificity of the method for estimation in the presence of degradants. The developed method was validated for parameters such as precision, accuracy, linearity, limit of detection, limit of quantification, ruggedness and robustness. The stability tests were also performed on drug substances as per International Conference on Harmonization guidelines.
Entropic control of the relative stability of triple-helical collagen peptide models.
Suárez, Ernesto; Díaz, Natalia; Suárez, Dimas
2008-11-27
Herein, we show that current methodologies in atomistic simulations can yield reliable standard free energy values in aqueous solution for the transition from the dissociated monomeric form to the triple-helix state of collagen model peptides. The calculations are performed on a prototypical highly stable triple-helical peptide, [(Pro-Hyp-Gly)10]3 (POG10), and on the so-called T3-785 triple-helix mimicking a fragment from the type III human collagen, which is more thermally labile. On the basis of extensive MD simulations in explicit solvent followed by molecular-mechanical and electrostatic Poisson-Boltzmann calculations complemented with an accurate estimation of the nonpolar contributions to solvation, the computed free energy change for the aggregation processes of the POG10 and T3-785 peptides leading to their triple-helices is -6.6 and -6.1 kcal/mol, respectively. For POG10, this value is in agreement with differential scanning calorimetric data. However, it is shown that conformational entropy, which is estimated by means of an expansion of mutual information functions, preferentially destabilizes the triple-helical state of T3-785 by around 4.6 kcal/mol, thus explaining its lower thermal stability. Altogether, our computational results allow us to ascertain, for the first time, the actual thermodynamic forces controlling the absolute and relative stability of collagen model peptides.
Halder, Partha; Nasabi, Mahyar; Jayasuriya, Niranjali; Shimeta, Jeff; Deighton, Margaret; Bhattacharya, Satinath; Mitchell, Arnan; Bhuiyan, Muhammed Ali
2014-01-01
Microstructure-based patterned surfaces with antifouling capabilities against a wide range of organisms are yet to be optimised. Several studies have shown that microtopographic features affect the settlement and the early stages of biofilm formation of microorganisms. It is speculated that the fluctuating stress-strain rates developed on patterned surfaces disrupt the stability of microorganisms. This study investigated the dynamic interactions of a motile bacterium (Escherichia coli) with microtopographies in relation to initial settlement. The trajectories of E. coli across a patterned surface of a microwell array within a microchannel-based flow cell system were assessed experimentally with a time-lapse imaging module. The microwell array was composed of 256 circular wells, each with diameter 10 μm, spacing 7 μm and depth 5 μm. The dynamics of E. coli over microwell-based patterned surfaces were compared with those over plain surfaces and an increased velocity of cell bodies was observed in the case of patterned surfaces. The experimental results were further verified and supported by computational fluid dynamic simulations. Finally, it was stated that the nature of solid boundaries and the associated microfluidic conditions play key roles in determining the dynamic stability of motile bacteria in the close vicinity over surfaces.
Rakkiyappan, R; Sivaranjani, R; Velmurugan, G; Cao, Jinde
2016-05-01
In this paper, the problem of the global O(t(-α)) stability and global asymptotic periodicity for a class of fractional-order complex-valued neural networks (FCVNNs) with time varying delays is investigated. By constructing suitable Lyapunov functionals and a Leibniz rule for fractional differentiation, some new sufficient conditions are established to ensure that the addressed FCVNNs are globally O(t(-α)) stable. Moreover, some sufficient conditions for the global asymptotic periodicity of the addressed FCVNNs with time varying delays are derived, showing that all solutions converge to the same periodic function. Finally, numerical examples are given to demonstrate the effectiveness and usefulness of our theoretical results.
Concept of sustained ordering and an ATP-related mechanism of life's origin
Galimov, Erik M
2009-01-01
This paper shows that the steady state of a system of conjugated reactions, which are characterized by disproportionation of entropy and proceed in the domain of linear interactions, is an attractor of ordering...
The forms of three-order Lagrangian equation in relative motion
Ma Shan-Jun; Liu Ming-Ping; Huang Pei-Tian
2005-01-01
In this paper, the general expressions of three-order Lagrangian equations in a motional coordinate system are obtained. In coordinate systems with some specific forms of motion, the expressions corresponding to these equations are also presented.
Stochastic robustness and relative stability of multiple pathways in biological networks
Guo, Yongyi; Qian, Min; Ge, Hao
2015-01-01
Multiple dynamic pathways always exist in biological networks, but their robustness against internal fluctuations and relative stability have not been well recognized and carefully analyzed yet. Here we try to address these issues through an illustrative example, namely the Siah-1/beta-catenin/p14/19 ARF loop of protein p53 dynamics. Its deterministic Boolean network model predicts that two parallel pathways with comparable magnitudes of attractive basins should exist after the protein p53 is activated when a cell becomes harmfully disturbed. Once the low but non-neglectable intrinsic fluctuations are incorporated into the model, we show that a phase transition phenomenon is emerged: in one parameter region the probability weights of the normal pathway, reported in experimental literature, are comparable with the other pathway which is seemingly abnormal with the unknown functions, whereas, in some other parameter regions, the probability weight of the abnormal pathway can even dominate and become globally at...
Relative stability of the FCC and HCP polymorphs with interacting polymers.
Mahynski, Nathan A; Kumar, Sanat K; Panagiotopoulos, Athanassios Z
2015-01-14
Recent work [Mahynski et al., Nat. Commun., 2014, 5, 4472] has demonstrated that the addition of long linear homopolymers thermodynamically biases crystallizing hard-sphere colloids to produce the hexagonal close-packed (HCP) polymorph over the closely related face-centered cubic (FCC) structure when the polymers and colloids are purely repulsive. In this report, we investigate the effects of thermal interactions on each crystal polymorph to explore the possibility of stabilizing the FCC crystal structure over the HCP. We find that the HCP polymorph remains at least as stable as its FCC counterpart across the entire range of interactions we explored, where interactions were quantified by the reduced second virial coefficient, -1.50 0, its tetrahedral voids produce a similar effect when B FCC crystals are elusive in these binary mixtures.
Stability of whey protein hydrolysate powders: effects of relative humidity and temperature.
Zhou, Peng; Liu, Dasong; Chen, Xiaoxia; Chen, Yingjia; Labuza, Theodore P
2014-05-01
Whey protein hydrolysate (WPH) is now considered as an important and special dairy protein ingredient for its nutritional and functional properties. The objectives of the present study were to investigate the effect of environmental relative humidity (RH) and storage temperature on the physicochemical stability of three WPH powders with hydrolysis degrees (DH) of 5.2%, 8.8% and 14.9%, respectively. The water sorption isotherms of the three WPH powders fitted the Guggenheim-Andersson-DeBoer model well. An increase in water content leaded to a decrease in glass transition temperature (Tg), following a linear Tg vs log water content relationship. Moreover, an increase in DH caused the decrease in Tg at the same water content. Changes in microstructure and colour occurred significantly when the WPH powders were stored at high environmental RH or temperature, especially for those with high DH. Copyright © 2013 Elsevier Ltd. All rights reserved.
Carotid plaque age is a feature of plaque stability inversely related to levels of plasma insulin.
Sara Hägg
Full Text Available BACKGROUND: The stability of atherosclerotic plaques determines the risk for rupture, which may lead to thrombus formation and potentially severe clinical complications such as myocardial infarction and stroke. Although the rate of plaque formation may be important for plaque stability, this process is not well understood. We took advantage of the atmospheric (14C-declination curve (a result of the atomic bomb tests in the 1950s and 1960s to determine the average biological age of carotid plaques. METHODOLOGY/PRINCIPAL FINDING: The cores of carotid plaques were dissected from 29 well-characterized, symptomatic patients with carotid stenosis and analyzed for (14C content by accelerator mass spectrometry. The average plaque age (i.e. formation time was 9.6±3.3 years. All but two plaques had formed within 5-15 years before surgery. Plaque age was not associated with the chronological ages of the patients but was inversely related to plasma insulin levels (p = 0.0014. Most plaques were echo-lucent rather than echo-rich (2.24±0.97, range 1-5. However, plaques in the lowest tercile of plaque age (most recently formed were characterized by further instability with a higher content of lipids and macrophages (67.8±12.4 vs. 50.4±6.2, p = 0.00005; 57.6±26.1 vs. 39.8±25.7, p<0.0005, respectively, less collagen (45.3±6.1 vs. 51.1±9.8, p<0.05, and fewer smooth muscle cells (130±31 vs. 141±21, p<0.05 than plaques in the highest tercile. Microarray analysis of plaques in the lowest tercile also showed increased activity of genes involved in immune responses and oxidative phosphorylation. CONCLUSIONS/SIGNIFICANCE: Our results show, for the first time, that plaque age, as judge by relative incorporation of (14C, can improve our understanding of carotid plaque stability and therefore risk for clinical complications. Our results also suggest that levels of plasma insulin might be involved in determining carotid plaque age.
Frescatada-Rosa, Márcia; Stanislas, Thomas; Backues, Steven K; Reichardt, Ilka; Men, Shuzhen; Boutté, Yohann; Jürgens, Gerd; Moritz, Thomas; Bednarek, Sebastian Y; Grebe, Markus
2014-12-01
Membranes of eukaryotic cells contain high lipid-order sterol-rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher-plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell-plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order-sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid-order membrane domain. The cell-plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate, and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell-plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid-order domain, and pave the way to explore potential feedback between lipid order and function of dynamin-related proteins during cytokinesis.
Jian Cao; Jirong Li; Wen Wang; Fang Yang; Zhuo Li; Laixing Li
2015-01-01
Background: Females can differentially deposit the immune factor lysozyme into eggs based on conditions of local breeding density and laying order.Materials: We collected 80 eggs from Great Cormorants(Phalacrocorax carbo) and then analyzed whether the level of lysozymes in the eggs is related to breeding density and laying order.Results: Between clutches,the level of lysozyme in eggs is positively related to breeding density; while within a clutch,the level of lysozyme is positively related to the laying order.Conclusion: When parents breed under conditions of high density,they allocate more lysozymes to their offspring,a trait adaptive to the local environment.That the increase in the level of lysozymes is a function of the laying order seems a necessary condition to mitigate the hierarchy among siblings for improving the survival of the entire clutch.
Dai, Ying; Hu, Yuchen; Jiang, Baojiang; Zou, Jinlong; Tian, Guohui; Fu, Honggang
2016-05-15
Composites of nano zero-valent iron (nZVI) and ordered mesoporous carbon (OMC) are prepared by using simultaneous carbothermal reduction methods. The reactivity and stability of nZVI are expected to be enhanced by embedding it in the ordered pore channels. The structure characteristics of nZVI/OMC and the removal pathway for hexavalent chromium (Cr(VI)) by nZVI/OMC are investigated. Results show that nZVI/OMC with a surface area of 715.16 m(2) g(-1) is obtained at 900 °C. nZVI with particle sizes of 20-30 nm is uniformly embedded in the OMC skeleton. The stability of nZVI is enhanced by surrounding it with a broad carbon layer and a little γ-Fe is derived from the passivation of α-Fe. Detection of ferric state (Fe 2p3/2, around 711.2eV) species confirms that part of the nZVI on the outer surface is inevitably oxidized by O2, even when unused. The removal efficiency of Cr(VI) (50 mg L(-1)) by nZVI/OMC is near 99% within 10 min through reduction (dominant mechanism) and adsorption. nZVI/OMC has the advantage in removal efficiency and reusability in comparison to nZVI/C, OMC and nZVI. This study suggests that nZVI/OMC has the potential for remediation of heavy metal pollution in water.
Absolute and relative temporal order memory for performed activities following stroke
Schoo, Linda A.; Van Zandvoort, Martine J E; Reijmer, Yael D.; Biessels, Geert Jan; Kappelle, L. Jaap; Postma, Albert
2014-01-01
Reconstructing the temporal order of events is a crucial part of episodic memory. The temporal dimension, however, is often discarded in clinical settings, and measurements of true temporal aspects of episodic memory are scarce. The present study assessed temporal memory in stroke patients and in
Personality, birth order and attachment styles as related to various types of jealousy
Buunk, Abraham (Bram)
1997-01-01
The relationships between jealousy, personality, attachment styles and birth order were examined in a sample of 100 Dutch men and 100 Dutch women. Three types of jealousy were examined: reactive jealousy (a negative response to the emotional or sexual involvement of the partner with someone else), p
Personality, birth order and attachment styles as related to various types of jealousy
Buunk, Abraham (Bram)
1997-01-01
The relationships between jealousy, personality, attachment styles and birth order were examined in a sample of 100 Dutch men and 100 Dutch women. Three types of jealousy were examined: reactive jealousy (a negative response to the emotional or sexual involvement of the partner with someone else),
Bachhuber, Frederik [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany); School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland (New Zealand); Krach, Alexander; Furtner, Andrea [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany); Söhnel, Tilo [School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland (New Zealand); Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, Auckland (New Zealand); Peter, Philipp; Rothballer, Jan [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany); Weihrich, Richard, E-mail: richard.weihrich@chemie.uni-r.de [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany)
2015-03-15
Pyrite-type and related systems appear for a wide range of binary and ternary combinations of transition metals and main group elements that form Zintl type dumbbell anion units. Those representatives with 20 valence electrons exhibit an extraordinary structural flexibility and interesting properties as low-gap semiconductors or thermoelectric and electrode materials. This work is devoted to the systematic exploration of novel compounds within the class of MTCh compounds (M=Ni, Pd, Pt; T=Si, Ge, Sn, Pb; Ch=S, Se, Te) by means of density functional calculations. Their preferred structures are predicted from an extended scheme of colored pyrites and marcasites. To determine their stabilities, competing binary MT{sub 2} and MCh{sub 2} boundary phases are taken into account as well as ternary M{sub 3}T{sub 2}Ch{sub 2} and M{sub 2}T{sub 3}Ch{sub 3} systems. Recently established stability diagrams are presented to account for MTCh ordering phenomena with a focus on a not-yet-reported ordering variant of the NiAs{sub 2} type. Due to the good agreement with experimental data available for several PtTCh systems, the predictions for the residual systems are considered sufficiently accurate. - Graphical abstract: Compositional and structural stability of MTCh compounds is investigated from first principle calculations. A conceptional approach is presented to study and predict novel stable and metastable compounds and structures of low gap semiconductors with TCh dumbbell units that are isoelectronic and structurally related to pyrite (FeS{sub 2}). - Highlights: • Study of compositional stability of MTCh vs. M{sub 3}T{sub 2}Ch{sub 2} and M{sub 2}T{sub 3}Ch{sub 3} compounds. • Study of structural stability of known and novel MTCh compounds. • Prediction of novel stable and metastable structures and compounds isoelectronic to pyrite, FeS{sub 2}.
Rekker, Roderik; Keijsers, Loes; Branje, Susan; Meeus, Wim
2015-06-01
This three-wave cohort-sequential longitudinal study (N = 1302) examined the development of two core political attitudes, economic egalitarianism and ethnocentrism, among Dutch youths between age 12 and 31. Longitudinal regression analyses revealed a curvilinear mean level development for both attitudes, reflecting an increased disagreement with economic redistribution and multiculturalism around late adolescence. Furthermore, attitudes became decreasingly polarized (i.e., less extreme) and increasingly stable with age. Finally, several effects of attitudes' correlates gradually changed: The effect of educational level on ethnocentrism increased with age, whereas the effect of gender diminished. Regional effects on ethnocentrism developed as youths resided in a new area. No age-related change was found in the effect of parental SES. Overall, these findings support the idea that attitudes mature during the formative phase of adolescence and that this process slows down during emerging adulthood. Furthermore, these results support developmental explanations for the association between attitudes and their correlates.
Chemical ordering in Cr3Al and relation to semiconducting behavior
Boekelheide, Z.; Stewart, D. A.; Hellman, F.
2012-08-01
Cr3Al shows semiconductor-like behavior which has been attributed to a combination of antiferromagnetism and chemical ordering of the Cr and Al atoms on the bcc sublattice. This article presents a detailed theoretical and experimental study of the chemical ordering in Cr3Al. Using density functional theory within the Korringa-Kohn-Rostoker (KKR) formalism, we consider five possible structures with the Cr3Al stoichiometry: a bcc solid solution, two-phase C11b Cr2Al+Cr, off-stoichiometric C11b Cr3Al, D03 Cr3Al, and X-phase Cr3Al. The calculations show that the chemically ordered, rhombohedrally distorted X-phase structure has the lowest energy of those considered and should, therefore, be the ground state found in nature, while the D03 structure has the highest energy and should not occur. While KKR calculations of the X phase indicate a pseudogap in the density of states, additional calculations using a full potential linear muffin-tin orbital approach and a plane-wave technique show a narrow band gap. Experimentally, thin films of Cr1-xAlx were grown and the concentration, growth temperature, and substrate were varied systematically. The peak resistivity (2400 μΩ-cm) is found for films with x=0.25, grown epitaxially on a 300 ∘C MgO substrate. At this x, a transition between nonmetallic and metallic behavior occurs at a growth temperature of about 400 ∘C, which is accompanied by a change in chemical ordering from X phase to C11b Cr3Al. These results clarify the range of possible structures for Cr3Al and the relationship between chemical ordering and electronic transport behavior.
Stability of concentration-related self-interstitial atoms in fusion material tungsten
Hong, Zhang; Shu-Long, Wen; Min, Pan; Zheng, Huang; Yong, Zhao; Xiang, Liu; Ji-Ming, Chen
2016-05-01
Based on the density functional theory, we calculated the structures of the two main possible self-interstitial atoms (SIAs) as well as the migration energy of tungsten (W) atoms. It was found that the difference of the and formation energies is 0.05-0.3 eV. Further analysis indicated that the stability of SIAs is closely related to the concentration of the defect. When the concentration of the point defect is high, SIAs are more likely to exist, SIAs are the opposite. In addition, the vacancy migration probability and self-recovery zones for these SIAs were researched by making a detailed comparison. The calculation provided a new viewpoint about the stability of point defects for self-interstitial configurations and would benefit the understanding of the control mechanism of defect behavior for this novel fusion material. Project supported by the Fundamental Research Funds for the Central Universities of Ministry of Education of China (Grant Nos. A0920502051411-5 and 2682014ZT30), the Program of International Science and Technology Cooperation, China (Grant No. 2013DFA51050), the National Magnetic Confinement Fusion Science Program, China (Grant Nos. 2011GB112001 and 2013GB110001), the National High Technology Research and Development Program of China (Grant No. 2014AA032701), the National Natural Science Foundation of China (Grant No. 11405138), the Southwestern Institute of Physics Funds, China, the Western Superconducting Technologies Company Limited, China, the Qingmiao Plan of Southwest Jiaotong University, China (Grant No. A0920502051517-6), and the China Postdoctoral Science Foundation (Grant No. 2014M560813).
Public Employee Impasse Resolution by Judicial Order: The Nebraska Court of Industrial Relations
Good, Wallace E.
1973-01-01
Discusses Nebraska's approach to public employee relations, the Nebraska Court of Industrial Relations. Suggests that the pattern developed in Nebraska, although it may appear somewhat more accidental than intentional, may offer a model to other States for strengthening impasse resoltuion machinery. (Author/JF)
Georg, Ira
2015-01-01
Based on a recent paper by Rothe and Sch\\"afer on compact binary systems, explicit expressions for canonical center and relative coordinates in terms of standard canonical coordinates are derived for spinless objects up to second post-Newtonian approximation of Einstein's theory of gravity. The inverse relations, i.e. the dependence of the standard canonical coordinates on the canonical center and relative coordinates, are also given up to the second post-Newtonian approximation. The famous Pythagorean-theorem-type Lorentz-invariant relation between the system's total energy or Hamiltonian squared, the rest energy or mass squared - solely depending on relative coordinates -, and the total linear momentum squared are explicitly shown through second post-Newtonian approximation.
Roles for ordered and bulk solvent in ligand recognition and docking in two related cavities.
Sarah Barelier
Full Text Available A key challenge in structure-based discovery is accounting for modulation of protein-ligand interactions by ordered and bulk solvent. To investigate this, we compared ligand binding to a buried cavity in Cytochrome c Peroxidase (CcP, where affinity is dominated by a single ionic interaction, versus a cavity variant partly opened to solvent by loop deletion. This opening had unexpected effects on ligand orientation, affinity, and ordered water structure. Some ligands lost over ten-fold in affinity and reoriented in the cavity, while others retained their geometries, formed new interactions with water networks, and improved affinity. To test our ability to discover new ligands against this opened site prospectively, a 534,000 fragment library was docked against the open cavity using two models of ligand solvation. Using an older solvation model that prioritized many neutral molecules, three such uncharged docking hits were tested, none of which was observed to bind; these molecules were not highly ranked by the new, context-dependent solvation score. Using this new method, another 15 highly-ranked molecules were tested for binding. In contrast to the previous result, 14 of these bound detectably, with affinities ranging from 8 µM to 2 mM. In crystal structures, four of these new ligands superposed well with the docking predictions but two did not, reflecting unanticipated interactions with newly ordered waters molecules. Comparing recognition between this open cavity and its buried analog begins to isolate the roles of ordered solvent in a system that lends itself readily to prospective testing and that may be broadly useful to the community.
1981-01-26
rials, the ordering of the chains, and the mechanical strenth of the resulting films or fibers . The basic goals are thus a molecular understanding of...polymers, cis and trans polybenzoxazoles (PBO) and polybenzothiazoles (PBT), form such phases, and energy calculations were therefore carried out to...Phys., 18, 000 (1981). 2. Phenylene Group Rotations and Nonplanar Conformations in Some Cis and Trans Polybenzoxazoles and Polybenzothiazoles, W. J
2000-01-01
In his celebrated paper Kontsevich has proved a theorem which manifestly gives a quantum product (deformation quantization formula) and states that changing coordinates leads to gauge equivalent star products. To illuminate his procedure, we make an arbitrary change of coordinates in the Moyal product and obtain the deformation quantization formula up to the third order. In this way, the Poisson bi-vector is shown to depend on \\hbar and not to satisfy the Jacobi identity. It is also shown tha...
Relative edge energy in the stability of transition metal nanoclusters of different motifs.
Zhao, X J; Xue, X L; Guo, Z X; Li, S F
2016-07-07
When a structure is reduced to a nanometer scale, the proportion of the edge atoms increases significantly, which can play a crucial role in determining both their geometric and electronic properties, as demonstrated by the recently established generalized Wulff construction principle [S. F. Li, et al., Phys. Rev. Lett., 2013, 111, 115501]. Consequently, it is of great interest to clarify quantitatively the role of the edge atoms that dominate the motifs of these nanostructures. In principle, establishing an effective method valid for determining the absolute value of the surface energy and particularly the edge energy for a given nanostructure is expected to resolve such a problem. However, hitherto, it is difficult to obtain the absolute edge energy of transition metal clusters, particularly when their sizes approach the nanometer regime. In this paper, taking Ru nanoclusters as a prototypical example, our first-principles calculations introduce the concept of relative edge energy (REE), reflecting the net edge atom effect over the surface (facet) atom effect, which is fairly powerful to quasi-quantitatively estimate the critical size at which the crossover occurs between different configurations of a given motif, such as from an icosahedron to an fcc nanocrystal. By contrast, the bulk effect should be re-considered to rationalize the power of the REE in predicting the relative stability of larger nanostructures between different motifs, such as fcc-like and hcp-like nanocrystals.
Stability of agronomic and yield related traits of Jatropha curcas accessions raised from cuttings
Mat, Nurul Hidayah Che; Yaakob, Zahira; Ratnam, Wickneswari
2016-11-01
Monitoring stability of agronomic and yield related traits is important for prediction of crop yields. This study was a latter study for the evaluation of 295 J. curcas individuals representing 21 accessions from eight countries at Biodiesel Research Station of Universiti Kebangsaan Malaysia, Kuala Pilah planted in December 2012. In this study, 183 J. curcas individuals were selected randomly from the population and their growth performance evaluated from December 2013 to December 2014. All the individual plants were raised from cuttings. The yield related data were recorded periodically and performance of each accession was analyzed using Statistical Analysis System (SAS) 9.4. Five traits which were number of fruits per plant (NFPP), number of fruits per inflorescence (NFPI), hundred seed weight (g) (HSW), number of seeds per plant (NSPP) and yield per plant (g) (YPP) showed significant differences among the accessions after two years of planting. Maximum values for each trait were 208 cm for plant height (PH), 31 for number of branches per plant (BPP), 115 for number of inflorescence per plant (NIPP), 582 for NFPP, 7 for NFPI, 307 for number of flowers per inflorescence (NFI), 17 for number of female flowers per inflorescence (NFFPI), 91.6 g for HSW, 1647.1 for NSPP and 927.6 g for YPP. Most of the plants which had performed well in the first year were among the best performers in the second year.
Gunjakar, Jayavant L; Kim, Tae Woo; Kim, Hyo Na; Kim, In Young; Hwang, Seong-Ju
2011-09-28
Mesoporous layer-by-layer ordered nanohybrids highly active for visible light-induced O(2) generation are synthesized by self-assembly between oppositely charged 2D nanosheets of Zn-Cr-layered double hydroxide (Zn-Cr-LDH) and layered titanium oxide. The layer-by-layer ordering of two kinds of 2D nanosheets is evidenced by powder X-ray diffraction and cross-sectional high resolution-transmission electron microscopy. Upon the interstratification process, the original in-plane atomic arrangements and electronic structures of the component nanosheets remain intact. The obtained heterolayered nanohybrids show a strong absorption of visible light and a remarkably depressed photoluminescence signal, indicating an effective electronic coupling between the two component nanosheets. The self-assembly between 2D inorganic nanosheets leads to the formation of highly porous stacking structure, whose porosity is controllable by changing the ratio of layered titanate/Zn-Cr-LDH. The resultant heterolayered nanohybrids are fairly active for visible light-induced O(2) generation with a rate of ∼1.18 mmol h(-1) g(-1), which is higher than the O(2) production rate (∼0.67 mmol h(-1) g(-1)) by the pristine Zn-Cr-LDH material, that is, one of the most effective visible light photocatalysts for O(2) production, under the same experimental condition. This result highlights an excellent functionality of the Zn-Cr-LDH-layered titanate nanohybrids as efficient visible light active photocatalysts. Of prime interest is that the chemical stability of the Zn-Cr-LDH is significantly improved upon the hybridization, a result of the protection of the LDH lattice by highly stable titanate layer. The present findings clearly demonstrate that the layer-by-layer-ordered assembly between inorganic 2D nanosheets is quite effective not only in improving the photocatalytic activity of the component semiconductors but also in synthesizing novel porous LDH-based hybrid materials with improved chemical
Philipp, M; Vergnat, C; Mueller, U; Sanctuary, R; Baller, J; Krueger, J K [Laboratoire de Physique des Materiaux, Universite du Luxembourg, 162A, avenue de la Faiencerie, L-1511 Luxembourg (Luxembourg); Possart, W [Fachbereich Werkstoffwissenschaften, Universitaet des Saarlandes, D-66123 Saarbruecken (Germany); Alnot, P [LPMI, Universite Nancy (France)], E-mail: martine.philipp@uni.lu
2009-01-21
The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies-including the generalized Cauchy relation-to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol-gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.
Philipp, M; Vergnat, C; Müller, U; Sanctuary, R; Baller, J; Possart, W; Alnot, P; Krüger, J K
2009-01-21
The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies-including the generalized Cauchy relation-to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol-gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.
Ryzhikov, I. S.; Semenkin, E. S.; Akhmedova, Sh A.
2017-02-01
A novel order reduction method for linear time invariant systems is described. The method is based on reducing the initial problem to an optimization one, using the proposed model representation, and solving the problem with an efficient optimization algorithm. The proposed method of determining the model allows all the parameters of the model with lower order to be identified and by definition, provides the model with the required steady-state. As a powerful optimization tool, the meta-heuristic Co-Operation of Biology-Related Algorithms was used. Experimental results proved that the proposed approach outperforms other approaches and that the reduced order model achieves a high level of accuracy.
MacCallum, M A H; Vera, R; Callum, Malcolm A.H. Mac; Mars, Marc; Vera, Ra\\"ul
2006-01-01
Perturbed stationary axisymmetric isolated bodies, e.g. stars, represented by a matter-filled interior and an asymptotically flat vacuum exterior joined at a surface where the Darmois matching conditions are satisfied, are considered. The initial state is assumed to be static. The perturbations of the matching conditions are derived and used as boundary conditions for the perturbed Ernst equations in the exterior region. The perturbations are calculated to second order. The boundary conditions are overdetermined: necessary and sufficient conditions for their compatibility are derived. The special case of perturbations of spherical bodies is given in detail.
Fransz, Duncan P; Huurnink, Arnold; Kingma, Idsart; van Dieën, Jaap H
2014-09-22
We aimed to verify whether the static phase after a single leg drop jump (DJ) landing on a force plate may serve as a proxy for a single leg stance (SLS) balance task, as this would increase the application possibilities of landing tasks in the evaluation of sensorimotor function in relation to injury rehabilitation or performance assessment. Twenty-five healthy participants performed two sessions of five valid trials for both tasks in a reproducibility-agreement design. Three postural stability outcome measures ('COP speed', 'COP sway' and 'Horizontal GRF') were calculated for DJ (5-20s after landing) and for SLS (15s), and were averaged per session. Paired T-tests revealed a learning effect of SLS for postural stability (4.6-6.1%; P-values 0.27). Only session 2 resulted in superior postural stability for SLS compared to DJ for 'COP speed' (5.0%; P=0.017) and 'Horizontal GRF' (8.2%; P=0.001). Bland and Altman methods demonstrated inter-session SD's of difference for DJ of 11-12% and for SLS of 10-12%, while inter-task SD's of difference ranged 10-17%. Precision ('SD within') was better for SLS concerning 'COP speed' (14-15% vs 13%) and 'Horizontal GRF' (18-20% vs 14-15%). In conclusion, postural stability during DJ and SLS cannot be considered interchangeable, due to a learning effect for SLS and inferior precision for DJ. However, a DJ task may be used as a proxy for static postural stability, although more than three trials are needed to achieve individual errors similar to SLS for 'COP speed' (4) and 'Horizontal GRF' (5).
Relation between dynamics, activity and thermal stability within the cholinesterase family.
Trovaslet, Marie; Trapp, Marcus; Weik, Martin; Nachon, Florian; Masson, Patrick; Tehei, Moeava; Peters, Judith
2013-03-25
Incoherent neutron scattering is one of the most powerful tools for studying dynamics in biological matter. Using the cold neutron backscattering spectrometer IN16 at the Institut Laue Langevin (ILL, Grenoble, France), temperature dependence of cholinesterases' dynamics (human butyrylcholinesterase from plasma: hBChE; recombinant human acetylcholinesterase: hAChE and recombinant mouse acetylcholinesterase: mAChE) was examined using elastic incoherent neutron scattering (EINS). The dynamics was characterized by the averaged atomic mean square displacement (MSD), associated with the sample flexibility at a given temperature. We found MSD values of hAChE above the dynamical transition temperature (around 200K) larger than for mAChE and hBChE, implying that hAChE is more flexible than the other ChEs. Activation energies for thermodynamical transition were extracted through the frequency window model (FWM) (Becker et al. 2004) [1] and turned out to increase from hBChE to mAChE and finally to hAChE, inversely to the MSDs relations. Between 280 and 316K, catalytic studies of these enzymes were carried out using thiocholine esters: at the same temperature, the hAChE activity was systematically higher than the mAChE or hBChE ones. Our results thus suggest a strong correlation between dynamics and activity within the ChE family. We also studied and compared the ChEs thermal inactivation kinetics. Here, no direct correlation with the dynamics was observed, thus suggesting that relations between enzyme dynamics and catalytic stability are more complex. Finally, the possible relation between flexibility and protein ability to grow in crystals is discussed.
METABOLIC AND BEHAVIORAL PARAMETERS IN NEWBORN PIGLETS IN RELATION TO BIRTH ORDER
H. SĂRĂNDAN
2013-12-01
Full Text Available The experiment had 2 phases:During the first phase 19 sows were monitored during farrowing; the piglets were numbered according to birth order, they were weighed and there were recorded the time each piglet was born and when it first suckled. There was calculated the time from the beginning of the farrowing until the time each piglet was born (TNPP and the time from birth until the first suckle (TPS. A statistical correlation was established between these parameters.During the second experimental phase, for 49 piglets from 5 sows were determined: birth weight, TPS, glycemia at birth (G0 and after the first suckle (G1, rectal temperature at birth (T0 and after the first suckles (T1. This data was statistically analyzed using the Mann-Whitney U test.Respecting the birth order, TPS is shorter for piglets born last (p<0.05. Average TPS was 23.04±2.49 minutes; during this time glycemia rises from 58.35 mg% to 64.35 mg% and rectal temperature drops from 38.58°C to 37.35°C. T0 is positively correlated with G0 (p<0.01 with G1 (p<0.01 and T1 (p<0.01. G0 is highly correlated to G1 (r=0.8855; p=0.
Wang, H W; Li, C L; Yuan, S L; Wang, J F; Lu, C L; Liu, J-M
2017-02-01
DyMnO3 hosts the less addressed duality of multiferroicity, owing to the Dy-Mn exchange striction and inverse Dzyaloshinskii-Moriya interaction between Mn spin pairs. Although the duality in DyMnO3 has been discussed earlier, there remains a question whether the Mn magnetic sublattice is necessarily multiferroic for generating the Dy-Mn exchange striction. In this work, we investigate the multiferroicity of Dy(Mn1-xFex)O3 (0 ≤ x ≤ 0.1) through detailed magnetic and ferroelectric characterization. It is found that Fe-doping continuously suppresses the independent Dy spin order but instead promotes the Dy-Mn(Fe) coupling. This coupling benefits the Dy-Mn(Fe) exchange striction which remarkably enhances the ferroelectric polarization at a low doping level (x ≤ 0.015), beyond which the Mn spiral spin order breaks down leading to collapse of the macroscopic polarization at x ≥ 0.05. This work discloses the crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction and thus highlights the duality of multiferroicity in DyMnO3.
Orbital stability of the restricted three body problem in General Relativity
2015-01-01
We consider the problem of orbital stability of the motion of a test particle in the restricted three-body problem, by using the orbital moment and its time derivative. We show that it is possible to get some insight into the stability properties of the motion of test particles, without knowing the exact solutions of the motion equations.
Orbital stability of the restricted three-body problem in General Relativity
Abishev, M.; Quevedo, H.; Toktarbay, S.; Zhami, B.
We consider the problem of orbital stability of the motion of a test particle in the restricted three-body problem, by using the orbital moment and its time derivative. We show that it is possible to get some insight into the stability properties of the motion of test particles, without knowing the exact solutions of the motion equations.
Orbital stability of the restricted three body problem in General Relativity
Abishev, M; Toktarbay, S; Zhami, B
2015-01-01
We consider the problem of orbital stability of the motion of a test particle in the restricted three-body problem, by using the orbital moment and its time derivative. We show that it is possible to get some insight into the stability properties of the motion of test particles, without knowing the exact solutions of the motion equations.
Power output of offshore wind farms in relation to atmospheric stability
Alblas, L.; Bierbooms, W.; Veldkamp, D.
2014-01-01
Atmospheric stability is known to influence wind farm power output, by affecting power losses due to wakes. This research tries to answer what atmospheric stability does to the power production and how conventional simulations using the Jensen wake model compare and can be improved. Data is used fro
Power output of offshore wind farms in relation to atmospheric stability
Alblas, L.; Bierbooms, W.A.A.M.; Veldkamp, D.
2014-01-01
Atmospheric stability is known to influence wind farm power output, by affecting power losses due to wakes. This research tries to answer what atmospheric stability does to the power production and how conventional simulations using the Jensen wake model compare and can be improved. Data is used
Social comparison and optimism about one's relational future : order effects in social judgment
Buunk, BP
1998-01-01
This research tested the hypothesis that when individuals first answer a question about relative evaluation, i.e. the degree in which they feel they are better or worse off than comparison others and next a question about general evaluation, i.e. the general judgment of one's situation or one's
2013-10-01
... necessary or appropriate action related to, chief compliance officer, swap valuation dispute, and risk... merchants are not required to submit swap valuation dispute or risk exposure reports to the Commission under... significant economic impact on a substantial number of small entities and either provide a...
Relative Performance Information, Rank Ordering and Employee Performance: A Research Note
Kramer, S.; Maas, V.S.; van Rinsum, M.
2016-01-01
We conduct a laboratory experiment to examine whether the provision of detailed relative performance information (i.e., information about the specific performance levels of peers) affects employee performance. We also investigate how – if at all – explicit ranking of performance levels affects how e
Monson, Eileen Q.; Dawis, Rene V.
Verbal analogy items, consisting of an ambiguous stimulus word pair and two unambiguous response word pairs as choice alternatives, were presented to psychology students in a counterbalanced design to discover if preferences existed between the two competing relations in each item. The data were analyzed to see if these preferences ordered…
Further results related to variance past lifetime class & associated orderings and their properties
Mahdy, Mervat
2016-11-01
If the random variable T denotes the lifetime of a unit, then the random variable T(t) = [ t - T ∣ T ≤ t ] , for a fixed t > 0, is known as the past lifetime. In this study, we present some new properties of the mean and variance for past lifetime classes (orderings). In addition, we consider an (n - r + 1) -out-of- n system with identical components where it is assumed that the lifetimes of the components are i.i.d. We assume that the system fails before time x, x > 0. Under these conditions, we are interested in studying the variance time elapsed since the failure of the components. Several properties of this function are studied and an example is provided. Finally, some applications in economic theory are described with real data.
Relation of birth order and scores on measures of pathological narcissism.
Curtis, J M; Cowell, D R
1993-02-01
To study the relationship between birth order and pathological narcissism, it was predicted that firstborn and only children would score significantly higher on standardized measures of pathological narcissism. Two such measures, the Millon Clinical Multiaxial Inventory and the Narcissistic Personality Inventory, were administered to 50 randomly selected subjects from a metropolitan mental health and family treatment agency. Subjects were asked to indicate their ordinal birth positions, e.g., first, middle, last, or only, and then were administered both instruments. Analysis supported the initial prediction by indicating that firstborn and only children had higher mean scores on the measures of pathological narcissism. It might be advisable for clinicians to identify patients' ordinal positions while appraising relevant diagnostic criteria and eventual treatment planning.
Relating Composition and Thermoelectric Stability of Pt-Rh Alloy Thermocouples
Pearce, J. V.; Greenen, A. D.; Smith, A.; Elliott, C. J.
2017-02-01
A simple model is presented which relates the electromotive force drift rate of Pt-Rh thermoelements to dS/dc, the sensitivity of the Seebeck coefficient, S, to rhodium mass fraction, c. The model has been tested by repeated measurements of a Pt-Rh thermocouple assembly consisting of five thermoelements, using a Co-C high-temperature fixed point (1324°C) for a total duration of 500 h. By considering various thermocouples from the assembly, it is demonstrated that in this case, remarkably, there is a linear relationship between the measured drift rate and the combined dS/dc, where the combination is determined by addition of the individual values for each wire. Particular emphasis is placed on evaluation of the uncertainties associated with the calculations. This result supports previous findings that the thermoelectric stability of Pt-Rh thermoelements improves as the rhodium mass fraction increases. Within this paradigm, it is shown that for a selected Pt-Rh thermoelement of any given composition, there exists a second thermoelement having a composition that yields a minimum drift when combined with the first to form a thermocouple.
Stability of snow cover on the territory of Russia in relation to climate change
A. N. Krenke
2012-01-01
Full Text Available The change of the snow cover stability characteristics over the Russian territory including regional and seasonal features of this change in the modern warming period of 1991–2008 in comparison with the period 1961–1990 are investigated in the paper using the data of 223 meteorological stations. Features of the snow cover regime related to teleconnection indices change of the North Atlantic Oscillation (NAO and the West Pacific (WP one are analyzed.Opposite tendencies of changes of the snow period duration were observed in most regions of Russia in each of the decades (1991–2008 in comparison with 1961–1990. Differently directed regional changes of the number of days without snow and interruption in snow cover were identified for each of the seasons in periods of intense warming in recent years compared to the baseline thirty years. Similar tendencies of seasonal changes of the number of days with snow depth more than 50 cm were observed in two decades in comparison with 1961–1990. The largest changes occurred in the winter and spring seasons. The spatial distribution of changes of the number of days with snow depth more than 50 cm also demonstrates the same tendency in the years with positive phase of the NAO and WP compared with the years of negative phase.
无
2002-01-01
According to archaeological data from about sixty samples the relative stability ofphysical and human geographical environment in the tropical zone of China is discussed in thispaper. Because of the superior natural environment, sufficient food resources and a sparsepopulation resulting in the absence of social requirement to transform the productive forces, theadvancement of economy and society was stagnated during prehistorical period in China's tropics.Compared with northern China, the appearance of ground stone tool stagnated about 3,000 years,the beginning of Bronze Age, about 1,000 years, and the agriculture, 2,500-3,000 years. The noceramics age continued till the early Neolithic Age and the appearance of colour or white ceramicswas 2,000 years later than that in northern China. The life form of migration to gather and to huntcontinued till the middle Neolithic Age, and the fixed settlement based on agriculture 1,000-2,000years stagnated. The clan commune just appeared at the end of the Neolithic Age which was 2,000-3,000 years later than that in northern China.
Lumpkin, G.R. [Australian Nuclear Science and Technology Organisation, Menai, New South Wales (Australia). Materials Div.; Mariano, A.N.
1996-08-01
Stoichiometric and non-stoichiometric (defect) pyrochlores crystallize during the magmatic and late magmatic-hydrothermal phases of carbonatite emplacement (T > 450--550 C, P < 2 kb). Defect pyrochlores can also form at low temperatures in laterite horizons during weathering. After crystallization, pyrochlore is subject to alteration by hydrothermal fluids (T {approximately} 550--200 C) and ground water. Alteration occurs primarily by ion exchange of low valence A-site cations together with O, F, and OH ions. The high valence cations Th and U are generally immobile; however, the authors have documented one example of hydrothermal alteration involving loss of U together with cation exchange at the B-site in samples from Mountain Pass, California. During laterite accumulation, the cation exchange rate of pyrochlore greatly exceeds the rate of matrix dissolution. The exceptional durability of pyrochlore in natural environments is related to the stability of the B-site framework cations. In carbonatites, defect pyrochlores may contain significant amounts of Si (up to 7.6 wt% SiO{sub 2}) which is negatively correlated with Nb.
Relative edge energy in the stability of transition metal nanoclusters of different motifs
Zhao, X. J.; Xue, X. L.; Guo, Z. X.; Li, S. F.
2016-06-01
When a structure is reduced to a nanometer scale, the proportion of the lowly-coordinated edge atoms increases significantly, which can play a crucial role in determining both their geometric and electronic properties, as demonstrated by the recently established generalized Wulff construction principle [S. F. Li, et al., Phys. Rev. Lett., 2013, 111, 115501]. Consequently, it is of great interest to clarify quantitatively the role of the edge atoms that dominate the motifs of these nanostructures. In principle, establishing an effective method valid for determining the absolute value of the surface energy and particularly the edge energy for a given nanostructure is expected to resolve such a problem. However, hitherto, it is difficult to obtain the absolute edge energy of transition metal clusters, particularly when their sizes approach the nanometer regime. In this paper, taking Ru nanoclusters as a prototypical example, our first-principles calculations introduce the concept of relative edge energy (REE), reflecting the net edge atom effect over the surface (facet) atom effect, which is fairly powerful to quasi-quantitatively estimate the critical size at which the crossover occurs between different configurations of a given motif, such as from an icosahedron to an fcc nanocrystal. By contrast, the bulk effect should be re-considered to rationalize the power of the REE in predicting the relative stability of larger nanostructures between different motifs, such as fcc-like and hcp-like nanocrystals.When a structure is reduced to a nanometer scale, the proportion of the lowly-coordinated edge atoms increases significantly, which can play a crucial role in determining both their geometric and electronic properties, as demonstrated by the recently established generalized Wulff construction principle [S. F. Li, et al., Phys. Rev. Lett., 2013, 111, 115501]. Consequently, it is of great interest to clarify quantitatively the role of the edge atoms that dominate the
Full-order fluctuation-dissipation relation for a class of nonequilibrium steady states
Ichiki, Akihisa; Ohzeki, Masayuki
2015-01-01
Acceleration of relaxation toward a fixed stationary distribution via violation of detailed balance was reported in the context of a Markov chain Monte Carlo method recently. Inspired by this result, systematic methods to violate detailed balance in Langevin dynamics were formulated by using exponential and rotational nonconservative forces. In the present paper, we accentuate that such specific nonconservative forces relate to the large deviation of total heat in an equilibrium state. The re...
Luchin, Alexander I.; Nadella, Murali V.P.; Thudi, Nanda K.; Dirksen, Wessel P.; Gulati, Parul; Fernandez, Soledad A.; Rosol, Thomas J.
2012-01-01
We demonstrated previously that parathyroid hormone-related protein (PTHrP) 1-141 mRNA is the least stable of three isoforms and is the only isoform that is stabilized by TGF-β. In order to understand how PTHrP mRNA is stabilized by TGF-β, we first sought to elucidate the mechanism(s) that are responsible for the instability of PTHrP isoform 1-141 mRNA. The 3′-UTR of isoform 1-141 contains four AU-rich elements (AREs), which are known to mediate mRNA degradation. We utilized a luciferase reporter system to test whether these four AREs are responsible for the short half-life of PTHrP 1-141 mRNA. Our results demonstrated that ARE elements in the 3′-UTR of PTHrP 1-141 mRNA play a significant role in regulation of the stability of the mRNA. It is known that AREs mediate their effects on mRNA stability through a number of ARE-binding proteins that recruit the exosome, a complex of exonucleases that degrades the mRNA. We identified tristetraproline (TTP) as an RNA-binding protein that may be involved in ARE-mediated degradation of PTHrP 1-141 mRNA. PMID:22960231
Luchin, Alexander I; Nadella, Murali V P; Thudi, Nanda K; Dirksen, Wessel P; Gulati, Parul; Fernandez, Soledad A; Rosol, Thomas J
2012-11-25
We demonstrated previously that parathyroid hormone-related protein (PTHrP) 1-141 mRNA is the least stable of three isoforms and is the only isoform that is stabilized by TGF-β. In order to understand how PTHrP mRNA is stabilized by TGF-β, we first sought to elucidate the mechanism(s) that are responsible for the instability of PTHrP isoform 1-141 mRNA. The 3'-UTR of isoform 1-141 contains four AU-rich elements (AREs), which are known to mediate mRNA degradation. We utilized a luciferase reporter system to test whether these four AREs are responsible for the short half-life of PTHrP 1-141 mRNA. Our results demonstrated that ARE elements in the 3'-UTR of PTHrP 1-141 mRNA play a significant role in regulation of the stability of the mRNA. It is known that AREs mediate their effects on mRNA stability through a number of ARE-binding proteins that recruit the exosome, a complex of exonucleases that degrades the mRNA. We identified tristetraproline (TTP) as an RNA-binding protein that may be involved in ARE-mediated degradation of PTHrP 1-141 mRNA. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Higher order almost automorphy, recurrence sets and the regionally proximal relation
Huang, Wen; Ye, Xiangdong
2011-01-01
In this paper, $d$-step almost automorphic systems are studied for $d\\in\\N$, which are the generalization of the classical almost automorphic ones. For a minimal topological dynamical system $(X,T)$ it is shown that the condition $x\\in X$ is $d$-step almost automorphic can be characterized via various subsets of $\\Z$ including the dual sets of $d$-step Poincar\\'e and Birkhoff recurrence sets, and Nil$_d$ Bohr$_0$-sets by considering $N(x,V)=\\{n\\in\\Z: T^nx\\in V\\}$, where $V$ is an arbitrary neighborhood of $x$. Moreover, it turns out that the condition $(x,y)\\in X\\times X$ is regionally proximal of order $d$ can also be characterized via various subsets of $\\Z$ including $d$-step Poincar\\'e and Birkhoff recurrence sets, $SG_d$ sets, the dual sets of Nil$_d$ Bohr$_0$-sets, and others by considering $N(x,U)=\\{n\\in\\Z: T^nx\\in U\\}$, where $U$ is an arbitrary neighborhood of $y$.
Davis, J C Séamus; Lee, Dung-Hai
2013-10-29
Unconventional superconductivity (SC) is said to occur when Cooper pair formation is dominated by repulsive electron-electron interactions, so that the symmetry of the pair wave function is other than an isotropic s-wave. The strong, on-site, repulsive electron-electron interactions that are the proximate cause of such SC are more typically drivers of commensurate magnetism. Indeed, it is the suppression of commensurate antiferromagnetism (AF) that usually allows this type of unconventional superconductivity to emerge. Importantly, however, intervening between these AF and SC phases, intertwined electronic ordered phases (IP) of an unexpected nature are frequently discovered. For this reason, it has been extremely difficult to distinguish the microscopic essence of the correlated superconductivity from the often spectacular phenomenology of the IPs. Here we introduce a model conceptual framework within which to understand the relationship between AF electron-electron interactions, IPs, and correlated SC. We demonstrate its effectiveness in simultaneously explaining the consequences of AF interactions for the copper-based, iron-based, and heavy-fermion superconductors, as well as for their quite distinct IPs.
Fröb, Markus B
2016-01-01
We prove the existence of the operator product expansion (OPE) in Euclidean Yang-Mills theories as a short-distance expansion, to all orders in perturbation theory. We furthermore show that the Ward identities of the underlying gauge theory are reflected in the OPE; especially, the OPE of an arbitrary number of gauge-invariant composite operators only involves gauge-invariant composite operators. Moreover, we derive recursion relations which allow to construct the OPE coefficients, the quantum BRST differential and the quantum antibracket order by order in perturbation theory, starting from the known free-theory objects. These relations are completely finite from the start, and do not need any further renormalisation as is usually the case in other approaches. Our results underline the importance of the OPE as a general structure underlying quantum field theories. The proofs are obtained within the framework of the Wilson-Wegner-Polchinski-Wetterich renormalisation group flow equations, and generalise similar...
Self-esteem stability in relation to narcissism and psychological well-being
Saša Zorjan
2013-06-01
Full Text Available The concept of self-esteem stability has an important role in the understanding of interpersonal and psychological functioning of individuals. The purpose of this study was to examine the relationship between self-esteem stability, narcissism and psychological well-being. A total of 178 participants (77% female participated in this study. The average age of the participants was 20, with the ages ranging from 18 to 26 years. The participants completed the following scales and questionnaires: Narcissistic Personality Inventory (NPI, Psychological Well-being Scales (PWBS, Instability of Selfesteem scale (ISES and Rosenberg Self-esteem scale (RSES. The Rosenberg Self-esteem scale was used to measure both self-esteem level and self-esteem stability, which was defined as dispersion of self-esteem level in time. For the purpose of obtaining data on self-esteem stability, the participants were required complete the Rosenberg self-esteem scale for a sequence of 14 days, other measures were completed during the first day of participation in the study. The main effects for self-esteem level emerged for narcissism and psychological well-being, in both cases higher levels of self-esteem was associated to higher levels of narcissism and psychological well-being. Self-esteem stability additionally explained a significant proportion of variability in narcissism and psychological well-being. Self-esteem stability was negatively associated with higher levels of narcissism and positively associated with higher levels of psychological well-being, above and beyond the effect of self-esteem level. When comparing two different measures of self-esteem stability, the results revealed that people with higher level of narcissism tend to overestimate their self-esteem stability. The results were consistent with our hypotheses. The importance of considering both level and stability of self-esteem, limitations of the present study and possibilities for further research are
Maria Joita
2007-12-01
Full Text Available In this paper we characterize the order relation on the set of all nondegenerate completely n-positive linear maps between C*-algebras in terms of a self-dual Hilbert module induced by each completely n-positive linear map.
2010-06-29
... COMMISSION Order Exempting the Trading and Clearing of Certain Products Related to ETFS Physical Swiss Gold... Physical Swiss Gold Shares (``Gold Products'') and ETFS Physical Silver Shares (``Silver Products'') (collectively, ``Gold and Silver Products''), which would be traded on national securities exchanges (as to...
A. Abiramasundari
2014-12-01
Full Text Available The stability of the drug actarit was studied under different stress conditions like hydrolysis (acid, alkaline and neutral, oxidation, photolysis and thermal degradation as recommended by International Conference on Harmonization (ICH guidelines. Drug was found to be unstable in acidic, basic and photolytic conditions and produced a common degradation product while oxidative stress condition produced three additional degradation products. Drug was impassive to neutral hydrolysis, dry thermal and accelerated stability conditions. Degradation products were identified, isolated and characterized by different spectroscopic analyses. Drug and the degradation products were synthesized by a new route using green chemistry. The chromatographic separation of the drug and its impurities was achieved in a phenomenex luna C18 column employing a step gradient elution by high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC–PDA–MS. A specific and sensitive stability-indicating assay method for the simultaneous determination of the drug actarit, its process related impurities and degradation products was developed and validated.
Kuang, Jun; Dai, Zhaohe; Liu, Luqi; Yang, Zhou; Jin, Ming; Zhang, Zhong
2015-05-01
Nanostructured carbon material based three-dimensional porous architectures have been increasingly developed for various applications, e.g. sensors, elastomer conductors, and energy storage devices. Maintaining architectures with good mechanical performance, including elasticity, load-bearing capacity, fatigue resistance and mechanical stability, is prerequisite for realizing these functions. Though graphene and CNT offer opportunities as nanoscale building blocks, it still remains a great challenge to achieve good mechanical performance in their microarchitectures because of the need to precisely control the structure at different scales. Herein, we fabricate a hierarchical honeycomb-like structured hybrid foam based on both graphene and CNT. The resulting materials possess excellent properties of combined high specific strength, elasticity and mechanical stability, which cannot be achieved in neat CNT and graphene foams. The improved mechanical properties are attributed to the synergistic-effect-induced highly organized, multi-scaled hierarchical architectures. Moreover, with their excellent electrical conductivity, we demonstrated that the hybrid foams could be used as pressure sensors in the fields related to artificial skin.Nanostructured carbon material based three-dimensional porous architectures have been increasingly developed for various applications, e.g. sensors, elastomer conductors, and energy storage devices. Maintaining architectures with good mechanical performance, including elasticity, load-bearing capacity, fatigue resistance and mechanical stability, is prerequisite for realizing these functions. Though graphene and CNT offer opportunities as nanoscale building blocks, it still remains a great challenge to achieve good mechanical performance in their microarchitectures because of the need to precisely control the structure at different scales. Herein, we fabricate a hierarchical honeycomb-like structured hybrid foam based on both graphene and
Ganghua Li
2014-08-01
Full Text Available Improvement of yield in rice (Oryza sativa L. is vital for ensuring food security in China. Both rice breeders and growers need an improved understanding of the relationship between yield and yield-related traits. New indica cultivars (53 in 2007 and 48 in 2008 were grown in Taoyuan, Yunnan province, to identify important components contributing to yield. Additionally, two standard indica rice cultivars with similar yield potentials, II You 107 (a large-panicle type and Xieyou 107 (a heavy-panicle type, were planted in Taoyuan, Yunnan province and Nanjing, Jiangsu province, from 2006 to 2008 to evaluate the stability of yield and yield-related attributes. Growth duration (GD, leaf area index (LAI, panicles per m2 (PN, and spikelets per m2 (SM were significantly and positively correlated with grain yield (GY over all years. Sequential path analysis identified PN and panicle weight (PW as important first-order traits that influenced grain yield. All direct effects were significant, as indicated by bootstrap analysis. Yield potential varied greatly across locations but not across years. Plant height (PH, days from heading to maturity (HM, and grain weight (GW were stable traits that showed little variation across sites or years, whereas GD (mainly the pre-heading period, PHP and PN varied significantly across locations. To achieve a yield of 15 t ha− 1, a cultivar should have a PH of 110–125 cm, a long GD with HM of approximately 40 days, a PN of 300–400 m− 2, and a GW of 29–31 mg.
Ganghua; Li; Jun; Zhang; Congdang; Yang; Yunpan; Song; Chengyan; Zheng; Shaohua; Wang; Zhenghui; Liu; Yanfeng; Ding
2014-01-01
Improvement of yield in rice(Oryza sativa L.) is vital for ensuring food security in China. Both rice breeders and growers need an improved understanding of the relationship between yield and yield-related traits. New indica cultivars(53 in 2007 and 48 in 2008) were grown in Taoyuan,Yunnan province, to identify important components contributing to yield. Additionally, two standard indica rice cultivars with similar yield potentials, II You 107(a large-panicle type) and Xieyou 107(a heavy-panicle type), were planted in Taoyuan, Yunnan province and Nanjing,Jiangsu province, from 2006 to 2008 to evaluate the stability of yield and yield-related attributes.Growth duration(GD), leaf area index(LAI), panicles per m2(PN), and spikelets per m2(SM) were significantly and positively correlated with grain yield(GY) over all years. Sequential path analysis identified PN and panicle weight(PW) as important first-order traits that influenced grain yield. All direct effects were significant, as indicated by bootstrap analysis. Yield potential varied greatly across locations but not across years. Plant height(PH), days from heading to maturity(HM), and grain weight(GW) were stable traits that showed little variation across sites or years, whereas GD(mainly the pre-heading period, PHP) and PN varied significantly across locations. To achieve a yield of 15 t ha-1, a cultivar should have a PH of 110–125 cm, a long GD with HM of approximately 40 days, a PN of 300–400 m-2, and a GW of 29–31 mg.
Soil aggregation and slope stability related to soil density, root length, and mycorrhiza
Graf, Frank; Frei, Martin
2013-04-01
Eco-engineering measures combine the use of living plants and inert mechanical constructions to protect slopes against erosion and shallow mass movement. Whereas in geotechnical engineering several performance standards and guidelines for structural safety and serviceability of construction exist, there is a lack of comparable tools in the field of ecological restoration. Various indicators have been proposed, including the fractal dimension of soil particle size distribution, microbiological parameters, and soil aggregate stability. We present results of an soil aggregate stability investigation and compare them with literature data of the angle of internal friction ?' which is conventionally used in slope stability analysis and soil failure calculation. Aggregate stability tests were performed with samples of differently treated moraine, including soil at low (~15.5 kN/m³) and high (~19.0 kN/m³) dry unit weight, soil planted with Alnus incana (White Alder) as well as the combination of soil planted with alder and inoculated with the mycorrhizal fungus Melanogaster variegatus s.l. After a 20 weeks growth period in a greenhouse, a total of 100 samples was tested and evaluated. Positive correlations were found between the soil aggregate stability and the three variables dry unit weight, root length per soil volume, and degree of mycorrhization. Based on robust statistics it turned out that dry unit weight and mycorrhization degree were strongest correlated with soil aggregate stability. Compared to the non-inoculated control plants, mycorrhized White Alder produced significantly more roots and higher soil aggregate stability. Furthermore, the combined biological effect of plant roots and mycorrhizal mycelia on aggregate stability on soil with low density (~15.5 kN/m³) was comparable to the compaction effect of the pure soil from 15.5 to ~19.0 kN/m³. Literature data on the effect of vegetation on the angle of internal friction ?' of the same moraine showed
Balajewicz, Maciej; Dowell, Earl
2015-01-01
For a projection-based reduced order model (ROM) to be stable and accurate, the dynamics of the truncated subspace must be taken into account. This paper proposes an approach for stabilizing and enhancing projection-based fluid ROMs in which truncated modes are accounted for \\textit{a priori} via a minimal rotation of the projection subspace. Attention is focused on the full non-linear compressible Navier-Stokes equations in specific volume form as a step toward a more general formulation for problems with generic non-linearities. Unlike traditional approaches, no empirical turbulence modeling terms are required, and consistency between the ROM and the full order model from which the ROM is derived is maintained. Mathematically, the approach is formulated as a quadratic matrix program on the Stiefel manifold. The reproductive as well as predictive capabilities of the method are evaluated on several compressible flow problems, including a problem involving laminar flow over an airfoil with a high angle of atta...
Mao, Zugang; Seidman, David N.; Wolverton, C.
2013-10-01
The solubility and stability of three possible ordered Al3Li structures in Al-Li alloys are studied using first-principles calculations: δ'-Al3Li(L12), δ-Al3Li(DO22), and β-Al3Li(DO3). We find that δ'-Al3Li(L12) is the most stable phase and β-Al3Li(DO3) is energetically unfavorable. The vibrational formation entropy makes a significant contribution to the solubility for all three ordered Al3Li structures and yields a 1.6-fold increase in the calculated solubility of δ'-Al3Li(L12), a 1.8-fold increase for δ-Al3Li(DO22), and a 2.5-fold increase for β-Al3Li(DO3). The solubility of δ'-Al3Li(L12) is greater than those of δ-Al3Li(DO22) and β-Al3Li(DO3), and the δ'-Al3Li(L12) solvus curve is in good agreement with the experimental one.
Self-esteem stability in relation to narcissism and psychological well-being
Košir, Katja; Zorjan, Saša
2015-01-01
The concept of self-esteem stability has an important role in the understanding of interpersonal and psychological functioning of individuals. The purpose of this study was to examine the relationship between self-esteem stability, narcissism and psychological well-being. A total of 178 participants (77% female) participated in this study. The average age of the participants was 20, with the ages ranging from 18 to 26 years. The participants completed the following scales and questionnaires: ...
Self-esteem stability in relation to narcissism and psychological well-being
Saša Zorjan; Katja Košir
2013-01-01
The concept of self-esteem stability has an important role in the understanding of interpersonal and psychological functioning of individuals. The purpose of this study was to examine the relationship between self-esteem stability, narcissism and psychological well-being. A total of 178 participants (77% female) participated in this study. The average age of the participants was 20, with the ages ranging from 18 to 26 years. The participants completed the following scales and questionnaires: ...
Naumov, Pance; Yu, Pei; Sakurai, Kenji
2008-07-03
The extraordinary stability of the photoinduced red form of a cationic spiropyran ( k approximately 10 (-6) s (-1) in water and approximately 10 (-6) to less than 10 (-8) s (-1) in the solid state) was employed to obtain in situ X-ray diffraction evidence of its molecular structure. By UV excitation under selected experimental conditions, on average, approximately one third of the cations in a single crystal of spiropyran iodide salt was converted and retained as the red form during the experiment. According to the structure of the mixed crystal, the ring opening, which is due to increased distance between the spiro oxygen and carbon atoms, is associated with slight molecular flattening caused by concurrent out-of-plane shift (11.2(5) degrees ) of the pyranopyridinium half and in-plane shift (4.8(7) degrees ) of the indoline half. The overall geometry change of the cation fits the steric requirements imposed by the ion packing in the crystal and can be viewed as molecular flattening caused by breaking of the spiroconjugation. The structure of the cation confirms that (at least in the case of cationic spiropyrans) the product is confined in the crystal mainly as a zwitterionic resonance structure in cis configuration similar to the (early) transition state. Although the positive charge of the closed form facilitates the ring-opening reaction by moving the reactant closer to the transition state, neither the weakening of the spiropyran C-O bond nor the space provided by the iodide alone can account for the stability of the product. Instead, the density functional theory calculations indicate that the stabilization of the red form of the cationic relative to the neutral spiropyran is thermodynamically controlled, probably through compensation of the charge within the zwitterion by the methylpyridinium group.
Approach Regarding a Framework for Risk Reporting in Order to Enhance the Related Good Practices
Mirela Nichita
2015-08-01
Full Text Available The nowadays accounting information user profile became more sophisticated and the financial reports face new challenges in accomplishing process to meet users’ needs. The purpose of financial reports is to provide useful information to users. According to International Accounting Standards Board, the utility of information is defined through the qualitative characteristics (fundamental and enhancing. The financial crisis emphasized the limits of financial reporting who has been unable to prevent investors about the risks they were facing. Some managers expressed reservations about the quality and relevance of corporate reporting, stating that the annual report is no longer a useful tool. Due to the current changes in business environment, managers have been highly motivated to rethink and improve the risk governance philosophy, processes and methodologies. The lack of quality, timely data and adequate systems to capture, report and measure the right information across the organization is a fundamental challenge to implementing and sustaining all aspects of effective risk management. Starting from 80s, the investors became more interested in narratives (Notes to financial statements, than in primary reports (financial position and performance. Our research suggests a framework for risk reporting with the main goal of improving the good practice in risk management field. Also, we will debate the relation between the qualitative characteristics of accounting information, transparency and risk, and explore the possibility of developing some good practices in risk reporting.
Volman, M.J.M.; Geuze, R.H.
A dynamic pattern approach is used to examine the relative phase stability of rhythmic coordination in 24 children with a Developmental Coordination Disorder (DCD) and 24 matched controls in two functionally different tasks - a within-subject task (bimanual coordination) and a subject-environment
Volman, M.J.M.; Geuze, R.H.
1998-01-01
A dynamic pattern approach is used to examine the relative phase stability of rhythmic coordination in 24 children with a Developmental Coordination Disorder (DCD) and 24 matched controls in two functionally different tasks - a within-subject task (bimanual coordination) and a subject-environment ta
75 FR 65366 - Recovery Policy RP9524.2, Landslides and Slope Stability Related to Public Facilities
2010-10-22
... SECURITY Federal Emergency Management Agency Recovery Policy RP9524.2, Landslides and Slope Stability Related to Public Facilities AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice of availability. SUMMARY: This document provides notice of the final Recovery Policy RP9524.2, Landslides and...
Monica, Dario Della; Goranko, Valentin; Montanari, Angelo;
2011-01-01
We compare the expressiveness of the fragments of Halpern and Shoham’s interval logic (HS), i.e., of all interval logics with modal operators associated with Allen’s relations between intervals in linear orders. We establish a complete set of interdefinability equations between these modal operat...... operators, and thus obtain a complete classification of the family of 212 fragments of HS with respect to their expressiveness. Using that result and a computer program, we have found that there are 1347 expressively different such interval logics over the class of all linear orders....
Role of organic matter on aggregate stability and related mechanisms through organic amendments
Zaher, Hafida
2010-05-01
To date, only a few studies have tried to simultaneously compare the role of neutral and uronic sugars and lipids on soil structural stability. Moreover, evidence for the mechanisms involved has often been established following wetting of moist aggregates after various pre-treatments thus altering aggregate structure and resulting in manipulations on altered aggregates on which the rapid wetting process may not be involved anymore. To the best of our knowledge, the objective of this work was to study the role of neutral and uronic sugars and lipids in affecting key mechanisms (swelling rate, pressure evolution) involved in the stabilization of soil structure. A long-term incubation study (48-wk) was performed on a clay loam and a silty-clay loam amended with de-inking-secondary sludge mix at three rates (8, 16 and 24 Mg dry matter ha-1), primary-secondary sludge mix at one rate (18 Mg oven-dry ha-1) and composted de-inking sludge at one rate (24 Mg ha-1). Different structural stability indices (stability of moist and dry aggregates, the amount of dispersible clay and loss of soil material following sudden wetting) were measured on a regular basis during the incubation, along with CO2 evolved, neutral and uronic sugar, and lipid contents. During the course of the incubations, significant increases in all stability indices were measured for both soil types. In general, the improvements in stability were proportional to the amount of C added as organic amendments. These improvements were linked to a very intense phase of C mineralization and associated with increases in neutral and uronic sugars as well as lipid contents. The statistical relationships found between the different carbonaceous fractions and stability indices were all highly significant and indicated no clear superiority of one fraction over another. Paper sludge amendments also resulted in significant decreases in maximum internal pressure of aggregate and aggregate swelling following immersion in water
Relative Stability of Peptide Sequence Ions Generated by Tandem Mass Spectrometry
Bythell, Benjamin J.; Hendrickson, Christopher L.; Marshall, Alan G.
2012-04-01
We report the use of unimolecular dissociation by infrared radiation for gaseous multiphoton energy transfer to determine relative activation energy (Ea,laser) for dissociation of peptide sequence ions. The sequence ions of interest are mass-isolated; the entire ion cloud is then irradiated with a continuous wave CO2 laser, and the first order rate constant, kd, is determined for each of a series of laser powers. Provided these conditions are met, a plot of the natural logarithm of kd versus the natural logarithm of laser power yields a straight line, whose slope provides a measure of Ea,laser. This method reproduces the Ea values from blackbody radiative dissociation (BIRD) for the comparatively large, singly and doubly protonated bradykinin ions (nominally y 9 and y 9 2+ ). The comparatively small sequence ion systems produce Ea,laser values that are systematic underestimates of theoretical barriers calculated with density functional theory (DFT). However, the relative Ea,laser values are in qualitative agreement with the mobile proton model and available theory. Additionally, novel protonated cyclic-dipeptide (diketopiperazine) fragmentation reactions are analyzed with DFT. FT-ICR MS provides access to sequence ions generated by electron capture dissociation, infrared multiphoton dissociation, and collisional activation methods (i.e., b n , y m , c n , z m • ions).
Kovacs, Julie A
2015-10-20
Many fundamental processes of life depend on the chemical energy stored in the O–O bond of dioxygen (O2), the majority of which is derived from photosynthetic H2O oxidation. Key steps in these processes involve Mn-, Fe-, or Cu-promoted formation or cleavage of O–O and O–H bonds, the mechanisms of which are not fully understood, especially with Mn. Metal–peroxo and high-valent metal–oxo species are proposed to be involved as intermediates. The metal ion properties that favor O–O and O–H bond formation versus cleavage have yet to be systematically explored. Herein we examine the O2 reactivity of a series of structurally related Mn(II) complexes and show that several metastable intermediates are observed, the relative stabilities of which depend on subtle differences in ligand architecture. We show that in contrast to Fe and Cu complexes, O2 binds irreversibly to Mn(II). By crystallizing an entire series of the first reported examples of Mn(III)–OOR peroxos as well as an O2-derived binuclear trans-μ-1,2-bridged Mn(III)–peroxo with varying degrees of O–O bond activation, we demonstrate that there are distinct correlations between spectroscopic, structural, and reactivity properties. Rate-limiting O–O bond cleavage is shown to afford a reactive species capable of abstracting H atoms from 2,4-tBu2-PhOH or 1,4-cyclohexadiene, depending on the ligand substituents. The weakly coordinated N-heterocycle Mn···Npy,quino distance is shown to correlate with the peroxo O–O bond length and modulate the π overlap between the filled πv*(O–O) and Mn dxz orbitals. We also show that there is a strong correlation between the peroxo → Mn charge transfer (CT) band and the peroxo O–O bond length. The energy difference between the CT bands associated with the peroxos possessing the shortest and longest O–O bonds shows that these distances are spectroscopically distinguishable. We show that we can use this spectroscopic parameter to estimate the O
JianhuaCHENG; JunfengLI; 等
1996-01-01
In this paper a mnechanical system is studied in which a rotor rotates around a fixed axis with a string suspended symmetric rigid body.All relative equilibrium strates and their stability are discussed.Considering the spinning angular velocity ω around the fixed vertical axis as a parameter,algebraic equations with this parameter are obtained,Every solution of the equations is relevant to a relative equilibrium state of the system.The existence of two important relative equilibrium states is discussed by numerical method developed in bifurcation theory in this paper,In addition,The lagrange's Theorem is used to determine the stability of the relative equilibrium state relevant to the solution of the algebraic equations.
Bernuzzi, Sebastiano; Dietrich, Tim
2016-09-01
The theoretical modeling of gravitational waveforms from binary neutron star mergers requires precise numerical relativity simulations. Assessing convergence of the numerical data and building the error budget is currently challenging due to the low accuracy of general-relativistic hydrodynamics schemes and to the grid resolutions that can be employed in (3 +1 )-dimensional simulations. In this work, we explore the use of high-order weighted-essentially-nonoscillatory (WENO) schemes in neutron star merger simulations and investigate the accuracy of the waveforms obtained with such methods. We find that high-order WENO schemes can be robustly employed for simulating the inspiral-merger phase and they significantly improve the assessment of the waveform's error budget with respect to finite-volume methods. High-order WENO schemes can be thus efficiently used for high-quality waveform production, and in future large-scale investigations of the binary parameter space.
Colburn, B. K.; Boland, J. S., III
1976-01-01
A new nonlinear stability criterion is developed by use of a class of Lyapunov functionals for model-reference adaptive systems (MRAS). Results are compared with traditional results, and a comparative design technique is used to illustrate its function in improving the transient response of an MRAS controller. For a particular system structure and class of input signals, the new stability criterion is shown to include traditional sufficiency stability conditions as a special case. An example is cited to illustrate the use of the nonlinear criterion and its definite advantages in helping improve the adaptive error transient response of a system. Analysis of results is effected by use of a linearization technique on the resulting adaptive equations.
Colburn, B. K.; Boland, J. S., III
1976-01-01
A new nonlinear stability criterion is developed by use of a class of Lyapunov functionals for model-reference adaptive systems (MRAS). Results are compared with traditional results, and a comparative design technique is used to illustrate its function in improving the transient response of an MRAS controller. For a particular system structure and class of input signals, the new stability criterion is shown to include traditional sufficiency stability conditions as a special case. An example is cited to illustrate the use of the nonlinear criterion and its definite advantages in helping improve the adaptive error transient response of a system. Analysis of results is effected by use of a linearization technique on the resulting adaptive equations.
Schmidt, Sandy; Genz, Maika; Balke, Kathleen; Bornscheuer, Uwe T
2015-11-20
Baeyer-Villiger monooxygenases (BVMO) belong to the class B of flavin-dependent monooxygenases (type I BVMOs) and catalyze the oxidation of (cyclic) ketones into esters and lactones. The prototype BVMO is the cyclohexanone monooxygenase (CHMO) from Acinetobacter sp. NCIMB 9871. This enzyme shows an impressive substrate scope with a high chemo-, regio- and/or enantioselectivity. BVMO reactions are often difficult, if not impossible to achieve by chemical approaches and this makes these enzymes thus highly desired candidates for industrial applications. Unfortunately, the industrial use is hampered by several factors related to the lack of stability of these biocatalysts. Thus, the aim of this study was to improve the CHMO's long-term stability, one of the most relevant parameter for biocatalytic processes, and additionally its stability against oxidation. We used an easy computational method for the prediction of stabilizing disulfide bonds in the CHMO-scaffold. The three most promising predicted disulfide pairs were created and biochemically characterized. The most oxidatively stable variant (Y411C-A463C) retained nearly 60% activity after incubation with 25 mM H2O2 whereas the wild type retained only 16%. In addition, one extra disulfide pair (T415C-A463C) was created and tested for increased stability. The melting temperature (Tm) of this variant was increased by 5°C with simultaneous improved long-term stability. After verification by ABD-F labeling that this mutant does not form a disulfide bond, single and double Cys/Ser mutants were prepared and investigated. Subsequent analysis revealed that the T415C single point variant is the most stable variant with a 30-fold increased long-term stability (33% residual activity after 24h incubation at 25°C) showcasing a great achievement for practical applications.
Smith, Kenneth J.; Meloni, Giovanni
2015-07-01
CBS-QB3 energy calculations show that the formation of a stable triplet cation for alkylperoxy radicals is dependent on factors other than the stability of the daughter cations exclusively. We have found that in cases where the daughter ions are not capable of stabilizing the cation through hyperconjugation, it is possible for the triplet cation to be bound. In many circumstances, CBS-QB3 calculations have found bound triplet cation states with 'negative dissociation energies.' These results are attributed to the effects that electron donating/withdrawing substituents have on the spin and charge densities of the resulting cations.
Natalia K. Prykarpatska
2005-01-01
Full Text Available The geometric structure of characteristic surfaces related with partial differential equations of first and higher orders is studied making use the vector field technique on hypersurfaces. It is shown, that corresponding characteristics are defined uniquely up to some smooth tensor fields, thereby supplying additional information about the suitable set of their solutions. In particular, it may be very useful for studying asymptotic properties of solutions to our partial differential equations under some boundary conditions.
Smarajit Das; Jayprokas Chakrabarti; Zhumur Ghosh; Satyabrata Sahoo; Bibekanand Mallick
2005-12-01
We analyse forty-seven chloroplast genes of the large subunit of RuBisCO, from the algal order Ectocarpales, sourced from GenBank. Codon-usage weighted by the nucleotide base-bias defines our score called the codon-impact-parameter. This score is used to obtain phylogenetic relations amongst the 47 Ectocarpales. We compare our classification with the ones done earlier.
Ao, Lu; Guo, You; Song, Xuekun; Guan, Qingzhou; Zheng, Weicheng; Zhang, Jiahui; Huang, Haiyan; Zou, Yi; Guo, Zheng; Wang, Xianlong
2017-05-08
Concerns are raised about the representativeness of cell lines for tumours due to the culture environment and misidentification. Liver is a major metastatic destination of many cancers, which might further confuse the origin of hepatocellular carcinoma cell lines. Therefore, it is of crucial importance to understand how well they can represent hepatocellular carcinoma. The HCC-specific gene pairs with highly stable relative expression orderings in more than 99% of hepatocellular carcinoma but with reversed relative expression orderings in at least 99% of one of the six types of cancer, colorectal carcinoma, breast carcinoma, non-small-cell lung cancer, gastric carcinoma, pancreatic carcinoma and ovarian carcinoma, were identified. With the simple majority rule, the HCC-specific relative expression orderings from comparisons with colorectal carcinoma and breast carcinoma could exactly discriminate primary hepatocellular carcinoma samples from both primary colorectal carcinoma and breast carcinoma samples. Especially, they correctly classified more than 90% of liver metastatic samples from colorectal carcinoma and breast carcinoma to their original tumours. Finally, using these HCC-specific relative expression orderings from comparisons with six cancer types, we identified eight of 24 hepatocellular carcinoma cell lines in the Cancer Cell Line Encyclopedia (Huh-7, Huh-1, HepG2, Hep3B, JHH-5, JHH-7, C3A and Alexander cells) that are highly representative of hepatocellular carcinoma. Evaluated with a REOs-based prognostic signature for hepatocellular carcinoma, all these eight cell lines showed the same metastatic properties of the high-risk metastatic hepatocellular carcinoma tissues. Caution should be taken for using hepatocellular carcinoma cell lines. Our results should be helpful to select proper hepatocellular carcinoma cell lines for biological experiments. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Elucidating Protactinium Hydrolysis: The Relative Stabilities of PaO2(H2O)(+) and PaO(OH)2(+).
Dau, Phuong D; Wilson, Richard E; Gibson, John K
2015-08-03
It is demonstrated that the gas-phase oxo-exchange of PaO2(+) with water is substantially faster than that of UO2(+), indicating that the Pa-O bonds are more susceptible to activation and formation of the bis-hydroxide intermediate, PaO(OH)2(+). To elucidate the nature of the water adduct of PaO2(+), hydration of PaO2(+) and UO2(+), as well as collision induced dissociation (CID) and ligand-exchange of the water adducts of PaO2(+) and UO2(+), was studied. The results indicate that, in contrast to UO2(H2O)(+), the protactinium oxo bis-hydroxide isomer, PaO(OH)2(+), is produced as a gas-phase species close in energy to the hydrate isomer, PaO2(H2O)(+). CID behavior similar to that of Th(OH)3(+) supports the assignment as PaO(OH)2(+). The gas-phase results are consistent with the spontaneous hydrolysis of PaO2(+) in aqueous solution, this in contrast to later AnO2(+) (An = U, Np, Pu), which forms stable hydrates in both solution and gas phase. In view of the known propensity for Th(IV) to hydrolyze, and previous gas-phase studies of other AnO2(+), it is concluded that the stabilities of oxo-hydroxides relative to oxide hydrates decreases in the order: Th(IV) > Pa(V) > U(V) > Np(V) > Pu(V). This trend suggests increasing covalency and decreasing ionicity of An-O bonds upon proceeding across the actinide series.
Myers, Douglas J; Lipscomb, Hester J; Epling, Carol; Hunt, Debra; Richardson, William; Smith-Lovin, Lynn; Dement, John M
2016-05-01
To explore whether surgical teams with greater stability among their members (ie, members have worked together more in the past) experience lower rates of sharps-related percutaneous blood and body fluid exposures (BBFE) during surgical procedures. A 10-year retrospective cohort study. A single large academic teaching hospital. Surgical teams participating in surgical procedures (n=333,073) performed during 2001-2010 and 2,113 reported percutaneous BBFE were analyzed. A social network measure (referred to as the team stability index) was used to quantify the extent to which surgical team members worked together in the previous 6 months. Poisson regression was used to examine the effect of team stability on the risk of BBFE while controlling for procedure characteristics and accounting for procedure duration. Separate regression models were generated for percutaneous BBFE involving suture needles and those involving other surgical devices. RESULTS The team stability index was associated with the risk of percutaneous BBFE (adjusted rate ratio, 0.93 [95% CI, 0.88-0.97]). However, the association was stronger for percutaneous BBFE involving devices other than suture needles (adjusted rate ratio, 0.92 [95% CI, 0.85-0.99]) than for exposures involving suture needles (0.96 [0.88-1.04]). Greater team stability may reduce the risk of percutaneous BBFE during surgical procedures, particularly for exposures involving devices other than suture needles. Additional research should be conducted on the basis of primary data gathered specifically to measure qualities of relationships among surgical team personnel.
Foam stability related to polymer permeability. 1: Low molecular weight additives
Bouma, R.H.B.; Nauta, W.J.; Arnauts, J.E.F.; Boomgaard, T. van den; Steuten, J.M.; Strathmann, H.
1997-01-01
In the production of polyethylene foams by extrusion with alkanes as a blowing agent, significant changes in the dimensions of extruded products are encountered. The dimensional stability of a foam with a structure of closed cells is improved by blending the polymer with small amounts of a low molec
Retrospective assessment of dryland soil stability in relation to grazing and climate change.
Washington-Allen, Robert A; West, Neil E; Ramsey, R Douglas; Phillips, Debra H; Shugart, Herman H
2010-01-01
Accelerated soil erosion is an aspect of dryland degradation that is affected by repeated intense drought events and land management activities such as commercial livestock grazing. A soil stability index (SSI) that detects the erosion status and susceptibility of a landscape at the pixel level, i.e., stable, erosional, or depositional pixels, was derived from the spectral properties of an archived time series (from 1972 to 1997) of Landsat satellite data of a commercial ranch in northeastern Utah. The SSI was retrospectively validated with contemporary field measures of soil organic matter and erosion status that was surveyed by US federal land management agencies. Catastrophe theory provided the conceptual framework for retrospective assessment of the impact of commercial grazing and soil water availability on the SSI. The overall SSI trend was from an eroding landscape in the early drier 1970s towards stable conditions in the wetter mid-1980s and late 1990s. The landscape catastrophically shifted towards an extreme eroding state that was coincident with the "The Great North American Drought of 1988". Periods of landscape stability and trajectories toward stability were coincident with extremely wet El Niño events. Commercial grazing had less correlation with soil stability than drought conditions. However, the landscape became more susceptible to erosion events under multiple droughts and grazing. Land managers now have nearly a year warning of El Niño and La Niña events and can adjust their management decisions according to predicted landscape erosion conditions.
AN INVESTIGATION INTERFACE STABILITY AND ITS RELATION TO GAS INGESTION IN VISCOSEALS.
purpose of seeking factors which have a significant role in the process of gas ingestion , or gas entrainment, in viscoseals. The simplified model of...by employing stroboscopic photography and high-speed motion picture photography. A phenomenological mechanism of gas ingestion was established...indicate that surface tension tends to stabilize the interface and prevent or delay gas ingestion . (Author)
Foam stability related to polymer permeability. 1: Low molecular weight additives
Bouma, R.H.B.; Nauta, W.J.; Arnauts, J.E.F.; Boomgaard, T. van den; Steuten, J.M.; Strathmann, H.
1997-01-01
In the production of polyethylene foams by extrusion with alkanes as a blowing agent, significant changes in the dimensions of extruded products are encountered. The dimensional stability of a foam with a structure of closed cells is improved by blending the polymer with small amounts of a low molec
Albacete, Alfonso A; Martínez-Andújar, Cristina; Pérez-Alfocea, Francisco
2014-01-01
Securing food production for the growing population will require closing the gap between potential crop productivity under optimal conditions and the yield captured by farmers under a changing environment, which is termed agronomical stability. Drought and salinity are major environmental factors contributing to the yield gap ultimately by inducing premature senescence in the photosynthetic source tissues of the plant and by reducing the number and growth of the harvestable sink organs by affecting the transport and use of assimilates between and within them. However, the changes in source-sink relations induced by stress also include adaptive changes in the reallocation of photoassimilates that influence crop productivity, ranging from plant survival to yield stability. While the massive utilization of -omic technologies in model plants is discovering hundreds of genes with potential impacts in alleviating short-term applied drought and salinity stress (usually measured as plant survival), only in relatively few cases has an effect on crop yield stability been proven. However, achieving the former does not necessarily imply the latter. Plant survival only requires water status conservation and delayed leaf senescence (thus maintaining source activity) that is usually accompanied by growth inhibition. However, yield stability will additionally require the maintenance or increase in sink activity in the reproductive structures, thus contributing to the transport of assimilates from the source leaves and to delayed stress-induced leaf senescence. This review emphasizes the role of several metabolic and hormonal factors influencing not only the source strength, but especially the sink activity and their inter-relations, and their potential to improve yield stability under drought and salinity stresses.
Tare, U. A.; Mody, F. K.; Mese, A. I. [Haliburton Energy Services, TX (United States)
2002-07-01
In order to develop a real-time wellbore (in)stability modelling capability, experimental work was carried out to investigate the role of the chemical potential of drilling fluids on transient pore pressure and time-dependent rock property alterations of shale formations. Time-dependent alterations in the pore pressure, acoustic and rock properties of formations subjected to compressive tri-axial test were recorded during the experiments involving the Pore Pressure Transmission (PPT) test. Based on the transient pore pressure of shale exposed to the test fluid presented here, the 20 per cent calcium chloride showed a very low membrane efficiency of 4.45 per cent. The need for a thorough understanding of the drilling fluid/shale interaction prior to applying any chemical potential wellbore (in)stability model to real-time drilling operations was emphasized. 9 refs., 5 figs.
Wang, Yan; Ge, Xihui; Zhang, Minqing; Zhu, Huaigong; Zhang, Zijian; Wang, Ming
2014-01-01
Growth characteristics of urea inclusion compounds with 1-decene, n-decane and mixture of 1-decene and n-decane (relative mass ratio = 1:1) were studied by CCD high-speed Camera. The present studies show that the speed of UICs growth in tunnel direction is faster than in vertical direction and the length of UICs with 1-decene is shorter than UICs with n-decane, and the length of UICs with mixture is between them due to the influence of the vinyl in 1-decene. The value of R = I(CH2)/I(CH3) and M = I(CHCH2)/I(CH3) in FTIR spectrum of UICs increasing with growth time demonstrates that urea prefers to include n-decane than 1-decene. 13C CP/MAS NMR studies of UICs indicate that the arrangement of 1-decene in UICs is CH3⋯CH3 and CHCH2⋯CH2CH. The arrangement of 1-decene in UICs leads to short chain of UICs with 1-decene in tunnel direction. The 13C CP/MAS NMR spectra of UICs with MIX reveal that there are three different types of arrangement: CH3⋯CH3, CHCH2⋯CH3 and CHCH2⋯CH2CH. The methods of FTIR and DSC were used to test the stability of UICs with different guests. The result shows that UICs with n-decane are stable than UICs with 1-decene. And the stability of UICs with mixture is in the middle.
Accioly, Antonio; Correia, Gilson; de Brito, Gustavo P.; de Almeida, José; Herdy, Wallace
2017-03-01
Simple prescriptions for computing the D-dimensional classical potential related to electromagnetic and gravitational models, based on the functional generator, are built out. These recipes are employed afterward as a support for probing the premise that renormalizable higher-order systems have a finite classical potential at the origin. It is also shown that the opposite of the conjecture above is not true. In other words, if a higher-order model is renormalizable, it is necessarily endowed with a finite classical potential at the origin, but the reverse of this statement is untrue. The systems used to check the conjecture were D-dimensional fourth-order Lee-Wick electrodynamics, and the D-dimensional fourth- and sixth-order gravity models. A special attention is devoted to New Massive Gravity (NMG) since it was the analysis of this model that inspired our surmise. In particular, we made use of our premise to resolve trivially the issue of the renormalizability of NMG, which was initially considered to be renormalizable, but it was shown some years later to be non-renormalizable. We remark that our analysis is restricted to local models in which the propagator has simple and real poles.
Chen, Jinbing
2016-03-01
From the bidirectional Lenard gradients, the negative-order Harry Dym (nHD) hierarchy is retrieved and further embedded into a bi-Hamiltonian structure displaying integrability. It follows from Neumann type integrable reduction that the nHD hierarchy is reduced to a family of backward Neumann type systems, which separate the temporal and spatial variables on the tangent bundle of an ellipsoid. Backward Neumann type systems are then proved to be completely integrable in the Liouville sense. From the commutativity of backward Neumann type flows, the relation between the nHD hierarchy and backward Neumann type systems is specified, where the involutive solutions of backward Neumann type systems yield the finite parametric solutions of the nHD hierarchy. Moreover, we propose the concept of a negative-order Novikov equation that cuts out a finite-dimensional invariant subspace for a negative-order integrable system, which paves an alternative way to obtain explicit solutions of negative-order integrable nonlinear evolution equations.
Sanchez-Sanchez, A.; Izquierdo, Maria Teresa; Ghanbaja, Jaafar; Medjahdi, Ghouti; Mathieu, Sandrine; Celzard, Alain; Fierro, Vanessa
2017-03-01
Hierarchically porous, oxygen-doped ordered mesoporous carbons (OMCs) were synthesised and compared for the first time from different types of plant-derived polyphenols through a nanocasting route: phloroglucinol, gallic acid, catechin and Mimosa tannin. All are secondary metabolites naturally occurring in various plant species and are available at low cost at the industrial scale. The infiltration was carried out in one single step without using toxic solvents or long polymerisation-stabilisation times. When applied as electrode materials for supercapacitors in 1 M H2SO4 electrolyte, those OMCs led to specific capacitances up to 277 F g-1 at 0.5 mV s-1 and high rate capabilities as measured by cyclic voltammetry, good cycling stabilities up to 5000 cycles and maximum energy densities between 15 and 8 W h kg-1 under exceptionally high power outputs ranging from 200 W kg-1 to 22.1 kW kg-1, respectively, in the range of current density of 0.1-12 A g-1, as determined by galvanostatic charge - discharge. Moreover, electrochemical impedance spectroscopy tests evidenced that the gallic acid-derived electrode exhibited the highest electrical conductivity and the fastest frequency response, making it an excellent candidate for high-power commercial devices.
Climente-Alarcon, V.; Antonino-Daviu, J.; Riera-Guasp, M.; Pons-Llinares, J.; Roger-Folch, J.; Jover-Rodriguez, P.; Arkkio, A.
2011-02-01
The present work is focused on the diagnosis of mixed eccentricity faults in induction motors via the study of currents demanded by the machine. Unlike traditional methods, based on the analysis of stationary currents (Motor Current Signature Analysis (MCSA)), this work provides new findings regarding the diagnosis approach proposed by the authors in recent years, which is mainly focused on the fault diagnosis based on the analysis of transient quantities, such as startup or plug stopping currents (Transient Motor Current Signature Analysis (TMCSA)), using suitable time-frequency decomposition (TFD) tools. The main novelty of this work is to prove the usefulness of tracking the transient evolution of high-order eccentricity-related harmonics in order to diagnose the condition of the machine, complementing the information obtained with the low-order components, whose transient evolution was well characterised in previous works. Tracking of high-order eccentricity-related harmonics during the transient, through their associated patterns in the time-frequency plane, may significantly increase the reliability of the diagnosis, since the set of fault-related patterns arising after application of the corresponding TFD tool is very unlikely to be caused by other faults or phenomena. Although there are different TFD tools which could be suitable for the transient extraction of these harmonics, this paper makes use of a Wigner-Ville distribution (WVD)-based algorithm in order to carry out the time-frequency decomposition of the startup current signal, since this is a tool showing an excellent trade-off between frequency resolution at both high and low frequencies. Several simulation results obtained with a finite element-based model and experimental results show the validity of this fault diagnosis approach under several faulty and operating conditions. Also, additional signals corresponding to the coexistence of the eccentricity and other non-fault related phenomena making
Carolyn F Wiber
Full Text Available Nonnative Bromus tectorum (cheatgrass is decimating sagebrush steppe, one of the largest ecosystems in the Western United States, and is causing regional-scale shifts in the predominant plant-fungal interactions. Sagebrush, a native perennial, hosts arbuscular mycorrhizal fungi (AMF, whereas cheatgrass, a winter annual, is a relatively poor host of AMF. This shift is likely intertwined with decreased carbon (C-sequestration in cheatgrass-invaded soils and alterations in overall soil fungal community composition and structure, but the latter remain unresolved. We examined soil fungal communities using high throughput amplicon sequencing (ribosomal large subunit gene in the 0-4 cm and 4-8 cm depth intervals of six cores from cheatgrass- and six cores from sagebrush-dominated soils. Sagebrush core surfaces (0-4 cm contained higher nitrogen and total C than cheatgrass core surfaces; these differences mirrored the presence of glomalin related soil proteins (GRSP, which has been associated with AMF activity and increased C-sequestration. Fungal richness was not significantly affected by vegetation type, depth or an interaction of the two factors. However, the relative abundance of seven taxonomic orders was significantly affected by vegetation type or the interaction between vegetation type and depth. Teloschistales, Spizellomycetales, Pezizales and Cantharellales were more abundant in sagebrush libraries and contain mycorrhizal, lichenized and basal lineages of fungi. Only two orders (Coniochaetales and Sordariales, which contain numerous economically important pathogens and opportunistic saprotrophs, were more abundant in cheatgrass libraries. Pleosporales, Agaricales, Helotiales and Hypocreales were most abundant across all libraries, but the number of genera detected within these orders was as much as 29 times lower in cheatgrass relative to sagebrush libraries. These compositional differences between fungal communities associated with cheatgrass
Carolyn F Weber
Full Text Available Nonnative Bromus tectorum (cheatgrass is decimating sagebrush steppe, one of the largest ecosystems in the Western United States, and is causing regional-scale shifts in the predominant plant-fungal interactions. Sagebrush, a native perennial, hosts arbuscular mycorrhizal fungi (AMF, whereas cheatgrass, a winter annual, is a relatively poor host of AMF. This shift is likely intertwined with decreased carbon (C-sequestration in cheatgrass-invaded soils and alterations in overall soil fungal community composition and structure, but the latter remain unresolved. We examined soil fungal communities using high throughput amplicon sequencing (ribosomal large subunit gene in the 0-4 cm and 4-8 cm depth intervals of six cores from cheatgrass- and six cores from sagebrush-dominated soils. Sagebrush core surfaces (0-4 cm contained higher nitrogen and total C than cheatgrass core surfaces; these differences mirrored the presence of glomalin related soil proteins (GRSP, which has been associated with AMF activity and increased C-sequestration. Fungal richness was not significantly affected by vegetation type, depth or an interaction of the two factors. However, the relative abundance of seven taxonomic orders was significantly affected by vegetation type or the interaction between vegetation type and depth. Teloschistales, Spizellomycetales, Pezizales and Cantharellales were more abundant in sagebrush libraries and contain mycorrhizal, lichenized and basal lineages of fungi. Only two orders (Coniochaetales and Sordariales, which contain numerous economically important pathogens and opportunistic saprotrophs, were more abundant in cheatgrass libraries. Pleosporales, Agaricales, Helotiales and Hypocreales were most abundant across all libraries, but the number of genera detected within these orders was as much as 29 times lower in cheatgrass relative to sagebrush libraries. These compositional differences between fungal communities associated with cheatgrass
Weber, Carolyn F; King, Gary M; Aho, Ken
2015-01-01
Nonnative Bromus tectorum (cheatgrass) is decimating sagebrush steppe, one of the largest ecosystems in the Western United States, and is causing regional-scale shifts in the predominant plant-fungal interactions. Sagebrush, a native perennial, hosts arbuscular mycorrhizal fungi (AMF), whereas cheatgrass, a winter annual, is a relatively poor host of AMF. This shift is likely intertwined with decreased carbon (C)-sequestration in cheatgrass-invaded soils and alterations in overall soil fungal community composition and structure, but the latter remain unresolved. We examined soil fungal communities using high throughput amplicon sequencing (ribosomal large subunit gene) in the 0-4 cm and 4-8 cm depth intervals of six cores from cheatgrass- and six cores from sagebrush-dominated soils. Sagebrush core surfaces (0-4 cm) contained higher nitrogen and total C than cheatgrass core surfaces; these differences mirrored the presence of glomalin related soil proteins (GRSP), which has been associated with AMF activity and increased C-sequestration. Fungal richness was not significantly affected by vegetation type, depth or an interaction of the two factors. However, the relative abundance of seven taxonomic orders was significantly affected by vegetation type or the interaction between vegetation type and depth. Teloschistales, Spizellomycetales, Pezizales and Cantharellales were more abundant in sagebrush libraries and contain mycorrhizal, lichenized and basal lineages of fungi. Only two orders (Coniochaetales and Sordariales), which contain numerous economically important pathogens and opportunistic saprotrophs, were more abundant in cheatgrass libraries. Pleosporales, Agaricales, Helotiales and Hypocreales were most abundant across all libraries, but the number of genera detected within these orders was as much as 29 times lower in cheatgrass relative to sagebrush libraries. These compositional differences between fungal communities associated with cheatgrass- and
Wiber, Carolyn F; King, Gary M; Aho, Ken
2015-01-01
Nonnative Bromus tectorum (cheatgrass) is decimating sagebrush steppe, one of the largest ecosystems in the Western United States, and is causing regional-scale shifts in the predominant plant-fungal interactions. Sagebrush, a native perennial, hosts arbuscular mycorrhizal fungi (AMF), whereas cheatgrass, a winter annual, is a relatively poor host of AMF. This shift is likely intertwined with decreased carbon (C)-sequestration in cheatgrass-invaded soils and alterations in overall soil fungal community composition and structure, but the latter remain unresolved. We examined soil fungal communities using high throughput amplicon sequencing (ribosomal large subunit gene) in the 0-4 cm and 4-8 cm depth intervals of six cores from cheatgrass- and six cores from sagebrush-dominated soils. Sagebrush core surfaces (0-4 cm) contained higher nitrogen and total C than cheatgrass core surfaces; these differences mirrored the presence of glomalin related soil proteins (GRSP), which has been associated with AMF activity and increased C-sequestration. Fungal richness was not significantly affected by vegetation type, depth or an interaction of the two factors. However, the relative abundance of seven taxonomic orders was significantly affected by vegetation type or the interaction between vegetation type and depth. Teloschistales, Spizellomycetales, Pezizales and Cantharellales were more abundant in sagebrush libraries and contain mycorrhizal, lichenized and basal lineages of fungi. Only two orders (Coniochaetales and Sordariales), which contain numerous economically important pathogens and opportunistic saprotrophs, were more abundant in cheatgrass libraries. Pleosporales, Agaricales, Helotiales and Hypocreales were most abundant across all libraries, but the number of genera detected within these orders was as much as 29 times lower in cheatgrass relative to sagebrush libraries. These compositional differences between fungal communities associated with cheatgrass- and
Barbado, David; Barbado, Luis C; Elvira, Jose L L; Dieën, Jaap H van; Vera-Garcia, Francisco J
2016-09-01
Trunk/core stability is considered a key component of training programs, because it could contribute to prevention of low-back and lower-limb injuries and to sports performance. Based on the specificity principle, sports-related trunk stability tests would be required in elite sports performance. However, there may be some generic qualities underlying trunk stability that can be assessed with nonspecific protocols, which are broadly used in sport and rehabilitation. To assess whether specific tests are needed in a high-performance context, we analyzed the influence of specialization in sports with large but qualitatively different balance control demands (judo and kayaking) on trunk stability and compared high-performance athletes with recreational athletes without a specific training history. Twenty-five judokas, sixteen kayakers and thirty-seven recreational athletes performed two trunk stability protocols: sudden loading, to assess trunk responses to external and unexpected perturbations; stable and unstable sitting, to assess the participant's ability to control trunk while sitting. Within-session test-retest reliability analyses were performed to support the between-groups comparison. Judokas showed lower angular displacement (0.199rad) against posterior loading than kayakers (0.221rad) probably because they are frequently challenged by higher sudden loads while they are pushed or pulled. Kayakers showed lower error (7.33mm), probably because they train and compete seated on unstable surfaces. Importantly, judokas and kayakers obtained better results than recreational athletes only in those tests designed according to the specific demands of each sport (psport training induces specific trunk stability adaptations, which are not revealed through nonspecific tests.
On the stability of the Bareiss and related Toeplitz factorization algorithms
Bojanczyk, Adam W; de Hoog, Frank R; Sweet, Douglas R
2010-01-01
This report contains a numerical stability analysis of factorization algorithms for computing the Cholesky decomposition of symmetric positive definite matrices of displacement rank 2. The algorithms in the class can be expressed as sequences of elementary downdating steps. The stability of the factorization algorithms follows directly from the numerical properties of algorithms for realizing elementary downdating operations. It is shown that the Bareiss algorithm for factorizing a symmetric positive definite Toeplitz matrix is in the class and hence the Bareiss algorithm is stable. Some numerical experiments that compare behavior of the Bareiss algorithm and the Levinson algorithm are presented. These experiments indicate that in general (when the reflection coefficients are not all positive) the Levinson algorithm is not stable; certainly it can give much larger residuals than the Bareiss algorithm.
On the relation between linear stability analysis and mean flow properties in wakes
Thiria, Benjamin; Wesfreid, Jose Eduardo
2015-01-01
In recent studies on wake stability, it has been observed that a simple linear stability analysis applied to the mean flow instead of the basic flow, could give an accurate prediction of the global mode selected frequency, although these phenomena are strongly non-linear. In this letter, we study the transient regime between the stationary (so called basic state) and unstationary solutions of the wake of a circular cylinder at Re=150. We show that the shift of the global frequency as a function of time due to strong non-linear effects, can be interpreted by a continuous mean flow correction induced by the growth of the instability. We show that during this transient regime, the mean state as a function of time plays the role of an instantaneous basic state on which the global frequency can be determined linearly.
Shakeel Ahmed Shaikh
2014-10-01
Full Text Available Assembly line operations generally involve physical and cognitive demanding tasks. Simultaneous performance under physical and cognitive demanding tasks may create physical and mental stresses. A within subjects study was carried out to determine the effects of assembly levels (variable assembly and consistent assembly on working conditions. Nine participants participated in a study and performed 8 conditions. The objective of the study was to determine the relation between physical and cognitive demands in a simulated task involving simultaneous performance of physical (fastening nuts and bolts and cognitive (code matching with secondary task of memorizing the code demanding task. Results showed the significant effects of assembly order (consisted of the concurrent performance of physically and cognitively demanding task on the working conditions. Quality of performance was affected by variable assembly order, high mental demand and above shoulder height
Sleep in Adolescents With Bipolar I Disorder: Stability and Relation to Symptom Change.
Gershon, Anda; Singh, Manpreet K
2017-01-01
Sleep disturbances are common features of bipolar disorder (BD), yet little is known about trajectories of sleep disturbances in youth with BD. Using longitudinal data, this study assessed the stability of sleep disturbances and their ability to predict symptom progression in adolescents diagnosed with BD compared to controls. Thirteen- to 19-year-olds meeting diagnostic criteria for BD I (n = 19, 16.2 ± 1.75 years, 57.9 % female, 68.4% Caucasian) and psychiatrically healthy age-comparable controls (n = 21, 15.7 ± 1.48 years. 52.4% female, 57.1% Caucasian) were assessed for sleep onset latency, number of awakenings, and wake time, separately for weekdays and weekends using a self-report questionnaire. Sleep indices and symptoms of mania (Young Mania Rating Scale) and depression (Children's Depression Rating Scale) were assessed at two time points, T1 and T2, approximately 12 months apart. Correlations were used to examine stability of sleep indices across time points and regression models to examine the effects of T1 sleep on T2 symptoms. Adolescents with BD showed low stability on most sleep indices, whereas controls showed high stability on all sleep indices. After controlling for T1 depression symptoms, more T1 weekend awakenings and weekend wake time predicted significantly greater T2 depression symptoms in youth with BD but not in controls. No significant associations were found between T1 sleep and T2 mania symptoms. These findings suggest that increased awakenings and wakefulness on weekends may represent an important therapeutic target for reducing depression in adolescents with BD.
Sleep in Adolescents with Bipolar I Disorder: Stability and Relation to Symptom Change
Gershon, Anda; Singh, Manpreet K.
2016-01-01
Objective Sleep disturbances are common features of bipolar disorder (BD) yet little is known about trajectories of sleep disturbances in youth with BD. Using longitudinal data, this study assessed the stability of sleep disturbances and their ability to predict symptom progression in adolescents diagnosed with BD compared to controls. Method Thirteen to nineteen year olds meeting diagnostic criteria for BD I (n = 19, 16.2 ±1.75 years, 57.9 % female, 68.4% Caucasian) and psychiatrically healthy age-comparable controls (n = 21, 15.7 ±1.48 years. 52.4% female, 57.1% Caucasian) were assessed for sleep onset latency, number of awakenings, and wake time, separately for weekdays and weekends using a self-report questionnaire. Sleep indices and symptoms of mania (Young Mania Rating Scale) and depression (Children's Depression Rating Scale) were assessed at two time points, T1 and T2, approximately twelve months apart. Correlations were used to examine stability of sleep indices across time points and regression models to examine the effects of T1 sleep on T2 symptoms. Results Adolescents with BD showed low stability on most sleep indices, whereas controls showed high stability on all sleep indices. After controlling for T1 depression symptoms, more T1 weekend awakenings and weekend wake time predicted significantly greater T2 depression symptoms in youth with BD but not in controls. No significant associations were found between T1 sleep and T2 mania symptoms. Conclusions These findings suggest that increased awakenings and wakefulness on weekends may represent an important therapeutic target for reducing depression in adolescents with BD. PMID:27472039
Narayana, M B V; Chandrasekhar, K B; Rao, B M
2014-09-01
A validated specific stability-indicating reverse-phase liquid chromatographic method was developed for the quantitative determination of Ambrisentan as well as its related substances in bulk samples, pharmaceutical dosage forms in the presence of degradation products and its related impurities. Forced degradation studies were performed on bulk samples of Ambrisentan as per the ICH-prescribed stress conditions using acid, base, oxidative, thermal stress and photolytic degradation to show the stability-indicating power of the LC method. Significant degradation in acidic, basic stress conditions was observed and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from the forced degradation studies and the impurity-spiked solution. Good resolution between the peaks corresponds to Ambrisentan-related impurities and degradation products from the analyte were achieved on a SunFire C18 column using a mobile phase consisting of a mixture of potassium dihydrogen orthophosphate at a pH adjusted to 2.5 with ortho-phosphoric acid in water and a mixture of acetonitrile:methanol using a simple linear gradient. The detection was carried out at 225 nm. The limit of detection and the limit of quantification for the Ambrisentan and its related impurities were established. The stressed test solutions were assayed against the qualified working standard of Ambrisentan and the mass balance in each case was between 98.9 and 100.3%, indicating that the developed LC method was stability indicating. Validation of the developed LC method was carried out as per the ICH requirements. The developed method was found to be suitable to check the quality of bulk samples of Ambrisentan at the time of batch release and also during its storage (long-term and accelerated stability).
Wu, Zhangxiong; Webley, Paul A; Zhao, Dongyuan
2010-06-15
Fuctionalization of porous carbon materials through chemical methods orientates the development of new hybrid materials with specific functions. In this paper, a comprehensive study of pore evolution, mesostructural oxidation resistance, and simultaneous surface functionalization of ordered mesoporous carbon FDU-15 under various oxidation conditions is presented for the first time. The mesostructure and pore evolution with increasing oxidative strength are retrieved from XRD, TEM, and N(2) sorption techniques. The textural properties can be conveniently manipulated by changing the oxidation parameters, including different oxidative solution, temperature, and duration. It is revealed that the mesoporous carbon FDU-15 shows excellent structural stability under severe oxidation treatments by acidic (NH(4))(2)S(2)O(8), HNO(3), and H(2)O(2) solutions, much more stable than the mesostructural analogue CMK-3 carbon prepared by the nanocasting method. The surface area and porosity deteriorate to a large extent compared to the pristine carbon, with the micropores/small mesopores as the major contribution to the deterioration. The micropore/small mesopore can be blocked by the attached surface oxides under mild oxidation, while reopened with more carbon layer dissolution under more severe conditions. Simultaneously, high densities of surface oxygen complexes, especially carboxylic groups, can be generated. The contents and properties of the surface oxygen-containing groups are extensively studied by FTIR, TG, elemental analyses, and water and ammonia adsorption techniques. Such surface-functionalized mesoporous carbons can be used as a highly efficient adsorbent for immobilization of heavy metal ions as well as functional organic and biomolecules, with high capacities and excellent binding capabilities. Thus, we believe that the functionalized mesoporous carbon materials can be utilized as a promising solid and stable support for water treatment and organic