A General Conditional Large Deviation Principle
NASA Astrophysics Data System (ADS)
La Cour, Brian R.; Schieve, William C.
2015-10-01
Given a sequence of Borel probability measures on a Hausdorff space which satisfy a large deviation principle (LDP), we consider the corresponding sequence of measures formed by conditioning on a set B. If the large deviation rate function I is good and effectively continuous, and the conditioning set has the property that (1) and (2) for all , then the sequence of conditional measures satisfies a LDP with the good, effectively continuous rate function , where if and otherwise.
Large Deviations and Gallavotti-Cohen Principle for Dissipative PDEs with Rough Noise
NASA Astrophysics Data System (ADS)
Jakšić, V.; Nersesyan, V.; Pillet, C.-A.; Shirikyan, A.
2015-05-01
We study a class of dissipative PDEs perturbed by an unbounded kick force. Under some natural assumptions, the restrictions of solutions to integer times form a homogeneous Markov process. Assuming that the noise is rough with respect to the space variables and has a non-degenerate law, we prove that the system in question satisfies a large deviation principle (LDP) in τ-topology. Under some additional hypotheses, we establish a Gallavotti-Cohen type symmetry for the rate function of an entropy production functional and the strict positivity and finiteness of the mean entropy production rate in the stationary regime. The latter result is applicable to PDEs with strong nonlinear dissipation.
NASA Astrophysics Data System (ADS)
Kraaij, Richard
2016-07-01
We prove the large deviation principle (LDP) for the trajectory of a broad class of finite state mean-field interacting Markov jump processes via a general analytic approach based on viscosity solutions. Examples include generalized Ehrenfest models as well as Curie-Weiss spin flip dynamics with singular jump rates. The main step in the proof of the LDP, which is of independent interest, is the proof of the comparison principle for an associated collection of Hamilton-Jacobi equations. Additionally, we show that the LDP provides a general method to identify a Lyapunov function for the associated McKean-Vlasov equation.
Large deviations and portfolio optimization
NASA Astrophysics Data System (ADS)
Sornette, Didier
Risk control and optimal diversification constitute a major focus in the finance and insurance industries as well as, more or less consciously, in our everyday life. We present a discussion of the characterization of risks and of the optimization of portfolios that starts from a simple illustrative model and ends by a general functional integral formulation. A major item is that risk, usually thought of as one-dimensional in the conventional mean-variance approach, has to be addressed by the full distribution of losses. Furthermore, the time-horizon of the investment is shown to play a major role. We show the importance of accounting for large fluctuations and use the theory of Cramér for large deviations in this context. We first treat a simple model with a single risky asset that exemplifies the distinction between the average return and the typical return and the role of large deviations in multiplicative processes, and the different optimal strategies for the investors depending on their size. We then analyze the case of assets whose price variations are distributed according to exponential laws, a situation that is found to describe daily price variations reasonably well. Several portfolio optimization strategies are presented that aim at controlling large risks. We end by extending the standard mean-variance portfolio optimization theory, first within the quasi-Gaussian approximation and then using a general formulation for non-Gaussian correlated assets in terms of the formalism of functional integrals developed in the field theory of critical phenomena.
NASA Astrophysics Data System (ADS)
Chen, Yong; Ge, Hao; Xiong, Jie; Xu, Lihu
2016-07-01
Fluctuation theorem is one of the major achievements in the field of nonequilibrium statistical mechanics during the past two decades. There exist very few results for steady-state fluctuation theorem of sample entropy production rate in terms of large deviation principle for diffusion processes due to the technical difficulties. Here we give a proof for the steady-state fluctuation theorem of a diffusion process in magnetic fields, with explicit expressions of the free energy function and rate function. The proof is based on the Karhunen-Loève expansion of complex-valued Ornstein-Uhlenbeck process.
Large Deviations in Fast-Slow Systems
NASA Astrophysics Data System (ADS)
Bouchet, Freddy; Grafke, Tobias; Tangarife, Tomás; Vanden-Eijnden, Eric
2016-02-01
The incidence of rare events in fast-slow systems is investigated via analysis of the large deviation principle (LDP) that characterizes the likelihood and pathway of large fluctuations of the slow variables away from their mean behavior—such fluctuations are rare on short time-scales but become ubiquitous eventually. Classical results prove that this LDP involves an Hamilton-Jacobi equation whose Hamiltonian is related to the leading eigenvalue of the generator of the fast process, and is typically non-quadratic in the momenta—in other words, the LDP for the slow variables in fast-slow systems is different in general from that of any stochastic differential equation (SDE) one would write for the slow variables alone. It is shown here that the eigenvalue problem for the Hamiltonian can be reduced to a simpler algebraic equation for this Hamiltonian for a specific class of systems in which the fast variables satisfy a linear equation whose coefficients depend nonlinearly on the slow variables, and the fast variables enter quadratically the equation for the slow variables. These results are illustrated via examples, inspired by kinetic theories of turbulent flows and plasma, in which the quasipotential characterizing the long time behavior of the system is calculated and shown again to be different from that of an SDE.
Special ergodic theorems and dynamical large deviations
NASA Astrophysics Data System (ADS)
Kleptsyn, Victor; Ryzhov, Dmitry; Minkov, Stanislav
2012-11-01
Let f : M → M be a self-map of a compact Riemannian manifold M, admitting a global SRB measure μ. For a continuous test function \\varphi\\colon M\\to R and a constant α > 0, consider the set Kφ,α of the initial points for which the Birkhoff time averages of the function φ differ from its μ-space average by at least α. As the measure μ is a global SRB one, the set Kφ,α should have zero Lebesgue measure. The special ergodic theorem, whenever it holds, claims that, moreover, this set has a Hausdorff dimension less than the dimension of M. We prove that for Lipschitz maps, the special ergodic theorem follows from the dynamical large deviations principle. We also define and prove analogous result for flows. Applying the theorems of Young and of Araújo and Pacifico, we conclude that the special ergodic theorem holds for transitive hyperbolic attractors of C2-diffeomorphisms, as well as for some other known classes of maps (including the one of partially hyperbolic non-uniformly expanding maps) and flows.
Convergence of large-deviation estimators.
Rohwer, Christian M; Angeletti, Florian; Touchette, Hugo
2015-11-01
We study the convergence of statistical estimators used in the estimation of large-deviation functions describing the fluctuations of equilibrium, nonequilibrium, and manmade stochastic systems. We give conditions for the convergence of these estimators with sample size, based on the boundedness or unboundedness of the quantity sampled, and discuss how statistical errors should be defined in different parts of the convergence region. Our results shed light on previous reports of "phase transitions" in the statistics of free energy estimators and establish a general framework for reliably estimating large-deviation functions from simulation and experimental data and identifying parameter regions where this estimation converges. PMID:26651644
Large Deviations: Advanced Probability for Undergrads
ERIC Educational Resources Information Center
Rolls, David A.
2007-01-01
In the branch of probability called "large deviations," rates of convergence (e.g. of the sample mean) are considered. The theory makes use of the moment generating function. So, particularly for sums of independent and identically distributed random variables, the theory can be made accessible to senior undergraduates after a first course in…
Large deviations for Markov processes with resetting.
Meylahn, Janusz M; Sabhapandit, Sanjib; Touchette, Hugo
2015-12-01
Markov processes restarted or reset at random times to a fixed state or region in space have been actively studied recently in connection with random searches, foraging, and population dynamics. Here we study the large deviations of time-additive functions or observables of Markov processes with resetting. By deriving a renewal formula linking generating functions with and without resetting, we are able to obtain the rate function of such observables, characterizing the likelihood of their fluctuations in the long-time limit. We consider as an illustration the large deviations of the area of the Ornstein-Uhlenbeck process with resetting. Other applications involving diffusions, random walks, and jump processes with resetting or catastrophes are discussed. PMID:26764673
Stochastic quantum Zeno by large deviation theory
NASA Astrophysics Data System (ADS)
Gherardini, Stefano; Gupta, Shamik; Saverio Cataliotti, Francesco; Smerzi, Augusto; Caruso, Filippo; Ruffo, Stefano
2016-01-01
Quantum measurements are crucial for observing the properties of a quantum system, which, however, unavoidably perturb its state and dynamics in an irreversible way. Here we study the dynamics of a quantum system being subjected to a sequence of projective measurements applied at random times. In the case of independent and identically distributed intervals of time between consecutive measurements, we analytically demonstrate that the survival probability of the system to remain in the projected state assumes a large deviation (exponentially decaying) form in the limit of an infinite number of measurements. This allows us to estimate the typical value of the survival probability, which can therefore be tuned by controlling the probability distribution of the random time intervals. Our analytical results are numerically tested for Zeno-protected entangled states, which also demonstrate that the presence of disorder in the measurement sequence further enhances the survival probability when the Zeno limit is not reached (as it happens in experiments). Our studies provide a new tool for protecting and controlling the amount of quantum coherence in open complex quantum systems by means of tunable stochastic measurements.
Large Deviation Analysis of Rapid Onset of Rain Showers.
Wilkinson, Michael
2016-01-01
Rainfall from ice-free cumulus clouds requires collisions of large numbers of microscopic droplets to create every raindrop. The onset of rain showers can be surprisingly rapid, much faster than the mean time required for a single collision. Large-deviation theory is used to explain this observation. PMID:26799046
Large Deviation Analysis of Rapid Onset of Rain Showers
NASA Astrophysics Data System (ADS)
Wilkinson, Michael
2016-01-01
Rainfall from ice-free cumulus clouds requires collisions of large numbers of microscopic droplets to create every raindrop. The onset of rain showers can be surprisingly rapid, much faster than the mean time required for a single collision. Large-deviation theory is used to explain this observation.
Large deviations of spread measures for Gaussian matrices
NASA Astrophysics Data System (ADS)
Deelan Cunden, Fabio; Vivo, Pierpaolo
2016-04-01
For a large n× m Gaussian matrix, we compute the joint statistics, including large deviation tails, of generalized and total variance—the scaled log-determinant H and trace T of the corresponding n× n covariance matrix. Using a Coulomb gas technique, we find that the Laplace transform of their joint distribution {{P}n}(h,t) decays for large n, m (with c=m/n≥slant 1 fixed) as {{\\hat{P}}n}(s,w)≈ \\exp ≤ft(-β {{n}2}J(s,w)\\right) , where β is the Dyson index of the ensemble and J(s, w) is a β-independent large deviation function, which we compute exactly for any c. The corresponding large deviation functions in real space are worked out and checked with extensive numerical simulations. The results are complemented with a finite n, m treatment based on the Laguerre–Selberg integral. The statistics of atypically small log-determinants is shown to be driven by the split-off of the smallest eigenvalue, leading to an abrupt change in the large deviation speed.
Large-deviation statistics of vorticity stretching in isotropic turbulence
NASA Astrophysics Data System (ADS)
Johnson, Perry L.; Meneveau, Charles
2016-03-01
A key feature of three-dimensional fluid turbulence is the stretching and realignment of vorticity by the action of the strain rate. It is shown in this paper, using the cumulant-generating function, that the cumulative vorticity stretching along a Lagrangian path in isotropic turbulence obeys a large deviation principle. As a result, the relevant statistics can be described by the vorticity stretching Cramér function. This function is computed from a direct numerical simulation data set at a Taylor-scale Reynolds number of Reλ=433 and compared to those of the finite-time Lyapunov exponents (FTLE) for material deformation. As expected, the mean cumulative vorticity stretching is slightly less than that of the most-stretched material line (largest FTLE), due to the vorticity's preferential alignment with the second-largest eigenvalue of strain rate and the material line's preferential alignment with the largest eigenvalue. However, the vorticity stretching tends to be significantly larger than the second-largest FTLE, and the Cramér functions reveal that the statistics of vorticity stretching fluctuations are more similar to those of the largest FTLE. In an attempt to relate the vorticity stretching statistics to the vorticity magnitude probability density function in statistically stationary conditions, a model Kramers-Moyal equation is constructed using the statistics encoded in the Cramér function. The model predicts a stretched-exponential tail for the vorticity magnitude probability density function, with good agreement for the exponent but significant difference (35%) in the prefactor.
Small shape deviations causes complex dynamics in large electric generators
NASA Astrophysics Data System (ADS)
Lundström, Niklas L. P.; Grafström, Anton; Aidanpää, Jan-Olov
2014-05-01
We prove that combinations of small eccentricity, ovality and/or triangularity in the rotor and stator can produce complex whirling motions of an unbalanced rotor in large synchronous generators. It is concluded which structures of shape deviations that are more harmful, in the sense of producing complex whirling motions, than others. For each such structure, we derive simplified equations of motions from which we conclude analytically the relation between shape deviations and mass unbalance that yield non-smooth whirling motions. Finally we discuss validity of our results in the sense of modeling of the unbalanced magnetic pull force.
Large deviation analysis of a simple information engine.
Maitland, Michael; Grosskinsky, Stefan; Harris, Rosemary J
2015-11-01
Information thermodynamics provides a framework for studying the effect of feedback loops on entropy production. It has enabled the understanding of novel thermodynamic systems such as the information engine, which can be seen as a modern version of "Maxwell's Dæmon," whereby a feedback controller processes information gained by measurements in order to extract work. Here, we analyze a simple model of such an engine that uses feedback control based on measurements to obtain negative entropy production. We focus on the distribution and fluctuations of the information obtained by the feedback controller. Significantly, our model allows an analytic treatment for a two-state system with exact calculation of the large deviation rate function. These results suggest an approximate technique for larger systems, which is corroborated by simulation data. PMID:26651675
From the Law of Large Numbers to Large Deviation Theory in Statistical Physics: An Introduction
NASA Astrophysics Data System (ADS)
Cecconi, Fabio; Cencini, Massimo; Puglisi, Andrea; Vergni, Davide; Vulpiani, Angelo
This contribution aims at introducing the topics of this book. We start with a brief historical excursion on the developments from the law of large numbers to the central limit theorem and large deviations theory. The same topics are then presented using the language of probability theory. Finally, some applications of large deviations theory in physics are briefly discussed through examples taken from statistical mechanics, dynamical and disordered systems.
Irreversible Langevin samplers and variance reduction: a large deviations approach
NASA Astrophysics Data System (ADS)
Rey-Bellet, Luc; Spiliopoulos, Konstantinos
2015-07-01
In order to sample from a given target distribution (often of Gibbs type), the Monte Carlo Markov chain method consists of constructing an ergodic Markov process whose invariant measure is the target distribution. By sampling the Markov process one can then compute, approximately, expectations of observables with respect to the target distribution. Often the Markov processes used in practice are time-reversible (i.e. they satisfy detailed balance), but our main goal here is to assess and quantify how the addition of a non-reversible part to the process can be used to improve the sampling properties. We focus on the diffusion setting (overdamped Langevin equations) where the drift consists of a gradient vector field as well as another drift which breaks the reversibility of the process but is chosen to preserve the Gibbs measure. In this paper we use the large deviation rate function for the empirical measure as a tool to analyze the speed of convergence to the invariant measure. We show that the addition of an irreversible drift leads to a larger rate function and it strictly improves the speed of convergence of ergodic average for (generic smooth) observables. We also deduce from this result that the asymptotic variance decreases under the addition of the irreversible drift and we give an explicit characterization of the observables whose variance is not reduced reduced, in terms of a nonlinear Poisson equation. Our theoretical results are illustrated and supplemented by numerical simulations.
De Roeck, W. E-mail: christian.maes@fys.kuleuven.be E-mail: marius.schutz@fys.kuleuven.be; Maes, C. E-mail: christian.maes@fys.kuleuven.be E-mail: marius.schutz@fys.kuleuven.be; Schütz, M. E-mail: christian.maes@fys.kuleuven.be E-mail: marius.schutz@fys.kuleuven.be; Netočný, K. E-mail: christian.maes@fys.kuleuven.be E-mail: marius.schutz@fys.kuleuven.be
2015-02-15
We study the projection on classical spins starting from quantum equilibria. We show Gibbsianness or quasi-locality of the resulting classical spin system for a class of gapped quantum systems at low temperatures including quantum ground states. A consequence of Gibbsianness is the validity of a large deviation principle in the quantum system which is known and here recovered in regimes of high temperature or for thermal states in one dimension. On the other hand, we give an example of a quantum ground state with strong nonlocality in the classical restriction, giving rise to what we call measurement induced entanglement and still satisfying a large deviation principle.
NASA Astrophysics Data System (ADS)
Mourragui, Mustapha; Orlandi, Enza
2013-01-01
A particle system with a single locally-conserved field (density) in a bounded interval with different densities maintained at the two endpoints of the interval is under study here. The particles interact in the bulk through a long-range potential parametrized by β⩾0 and evolve according to an exclusion rule. It is shown that the empirical particle density under the diffusive scaling solves a quasilinear integro-differential evolution equation with Dirichlet boundary conditions. The associated dynamical large deviation principle is proved. Furthermore, when β is small enough, it is also demonstrated that the empirical particle density obeys a law of large numbers with respect to the stationary measures (hydrostatic). The macroscopic particle density solves a non-local, stationary, transport equation.
Interpretation of large-scale deviations from the Hubble flow
NASA Astrophysics Data System (ADS)
Grinstein, B.; Politzer, H. David; Rey, S.-J.; Wise, Mark B.
1987-03-01
The theoretical expectation for large-scale streaming velocities relative to the Hubble flow is expressed in terms of statistical correlation functions. Only for objects that trace the mass would these velocities have a simple cosmological interpretation. If some biasing effects the objects' formation, then nonlinear gravitational evolution is essential to predicting the expected large-scale velocities, which also depend on the nature of the biasing.
Large deviations of the current in a two-dimensional diffusive system
Perez-Espigares, C.; Pozo, J. J. del; Garrido, P. L.; Hurtado, P. I.
2011-03-24
In this notes we study the large deviations of the time-averaged current in the two-dimensional (2D) Kipnis-Marchioro-Presutti model of energy transport when subject to a boundary gradient. We use the tools of hydrodynamic fluctuation theory, supplemented with an appropriate generalization of the additivity principle. As compared to its one-dimensional counterpart, which amounts to assume that the optimal profiles responsible of a given current fluctuation are time-independent, the 2D additivity conjecture requires an extra assumption, i.e. that the optimal, divergence-free current vector field associated to a given fluctuation of the time-averaged current is in fact constant across the system. Within this context we show that the current distribution exhibits in general non-Gaussian tails. The ensuing optimal density profile can be either monotone for small current fluctuations, or non-monotone with a single maximum for large enough current deviations. Furthermore, this optimal profile remains invariant under arbitrary rotations of the current vector, providing a detailed example of the recently introduced Isometric Fluctuation Relation.
NASA Astrophysics Data System (ADS)
Filiasi, Mario; Livan, Giacomo; Marsili, Matteo; Peressi, Maria; Vesselli, Erik; Zarinelli, Elia
2014-09-01
Large deviations for fat tailed distributions, i.e. those that decay slower than exponential, are not only relatively likely, but they also occur in a rather peculiar way where a finite fraction of the whole sample deviation is concentrated on a single variable. The regime of large deviations is separated from the regime of typical fluctuations by a phase transition where the symmetry between the points in the sample is spontaneously broken. For stochastic processes with a fat tailed microscopic noise, this implies that, while typical realizations are well described by a diffusion process with continuous sample paths, large deviation paths are typically discontinuous. For eigenvalues of random matrices with fat tailed distributed elements, a large deviation where the trace of the matrix is anomalously large concentrates on just a single eigenvalue, whereas in the thin tailed world the large deviation affects the whole distribution. These results find a natural application to finance. Since the price dynamics of financial stocks are characterized by fat tailed increments, large fluctuations in stock prices are expected to be realized by discrete jumps. Interestingly, we find that large excursions of prices are more likely realized by continuous drifts rather than by discontinuous jumps. Indeed, auto correlations suppress the concentration of large deviations. Financial covariance matrices also exhibit an anomalously large eigenvalue, the market mode, as compared to the prediction of random matrix theory. We show that this is explained by a large deviation with excess covariance rather than by one with excess volatility.
NASA Astrophysics Data System (ADS)
Teodorescu, Razvan
2009-10-01
Systems of oscillators coupled non-linearly (stochastically or not) are ubiquitous in nature and can explain many complex phenomena: coupled Josephson junction arrays, cardiac pacemaker cells, swarms or flocks of insects and birds, etc. They are know to have a non-trivial phase diagram, which includes chaotic, partially synchronized, and fully synchronized phases. A traditional model for this class of problems is the Kuramoto system of oscillators, which has been studied extensively for the last three decades. The model is a canonical example for non-equilibrium, dynamical phase transitions, so little understood in physics. From a stochastic analysis point of view, the transition is described by the large deviations principle, which offers little information on the scaling behavior near the critical point. I will discuss a special case of the model, which allows a rigorous analysis of the critical properties of the model, and reveals a new, anomalous scaling behavior in the vicinity of the critical point.
Back in the saddle: Large-deviation statistics of the cosmic log-density field
NASA Astrophysics Data System (ADS)
Uhlemann, C.; Codis, S.; Pichon, C.; Bernardeau, F.; Reimberg, P.
2016-05-01
We present a first principle approach to obtain analytical predictions for spherically-averaged cosmic densities in the mildly non-linear regime that go well beyond what is usually achieved by standard perturbation theory. A large deviation principle allows us to compute the leading-order cumulants of average densities in concentric cells. In this symmetry, the spherical collapse model leads to cumulant generating functions that are robust for finite variances and free of critical points when logarithmic density transformations are implemented. They yield in turn accurate density probability distribution functions (PDFs) from a straightforward saddle-point approximation valid for all density values. Based on this easy-to-implement modification, explicit analytic formulas for the evaluation of the one- and two-cell PDF are provided. The theoretical predictions obtained for the PDFs are accurate to a few percent compared to the numerical integration, regardless of the density under consideration and in excellent agreement with N-body simulations for a wide range of densities. This formalism should prove valuable for accurately probing the quasi-linear scales of low redshift surveys for arbitrary primordial power spectra.
Back in the saddle: large-deviation statistics of the cosmic log-density field
NASA Astrophysics Data System (ADS)
Uhlemann, C.; Codis, S.; Pichon, C.; Bernardeau, F.; Reimberg, P.
2016-08-01
We present a first principle approach to obtain analytical predictions for spherically averaged cosmic densities in the mildly non-linear regime that go well beyond what is usually achieved by standard perturbation theory. A large deviation principle allows us to compute the leading order cumulants of average densities in concentric cells. In this symmetry, the spherical collapse model leads to cumulant generating functions that are robust for finite variances and free of critical points when logarithmic density transformations are implemented. They yield in turn accurate density probability distribution functions (PDFs) from a straightforward saddle-point approximation valid for all density values. Based on this easy-to-implement modification, explicit analytic formulas for the evaluation of the one- and two-cell PDF are provided. The theoretical predictions obtained for the PDFs are accurate to a few per cent compared to the numerical integration, regardless of the density under consideration and in excellent agreement with N-body simulations for a wide range of densities. This formalism should prove valuable for accurately probing the quasi-linear scales of low-redshift surveys for arbitrary primordial power spectra.
Two-scale large deviations for chemical reaction kinetics through second quantization path integral
NASA Astrophysics Data System (ADS)
Li, Tiejun; Lin, Feng
2016-04-01
Motivated by the study of rare events for a typical genetic switching model in systems biology, in this paper we aim to establish the general two-scale large deviations for chemical reaction systems. We build a formal approach to explicitly obtain the large deviation rate functionals for the considered two-scale processes based upon the second quantization path integral technique. We get three important types of large deviation results when the underlying two timescales are in three different regimes. This is realized by singular perturbation analysis to the rate functionals obtained by the path integral. We find that the three regimes possess the same deterministic mean-field limit but completely different chemical Langevin approximations. The obtained results are natural extensions of the classical large volume limit for chemical reactions. We also discuss its implication on the single-molecule Michaelis-Menten kinetics. Our framework and results can be applied to understand general multi-scale systems including diffusion processes.
Large deviations of the shifted index number in the Gaussian ensemble
NASA Astrophysics Data System (ADS)
Pérez Castillo, Isaac
2016-06-01
We show that, using the Coulomb fluid approach, we are able to derive a rate function \\Psi(c,x) of two variables that captures: (i) the large deviations of bulk eigenvalues; (ii) the large deviations of extreme eigenvalues (both left and right large deviations); (iii) the statistics of the fraction c of eigenvalues to the left of a position x. Thus, \\Psi(c,x) explains the full order statistics of the eigenvalues of large random Gaussian matrices as well as the statistics of the shifted index number. All our analytical findings are thoroughly compared with Monte Carlo simulations, obtaining excellent agreement. A summary of preliminary results has already been presented in Pérez Castillo (2014 Phys. Rev. E 90 040102) in the context of one-dimensional trapped spinless fermions in a harmonic potential.
Efficiency and large deviations in time-asymmetric stochastic heat engines
Gingrich, Todd R.; Rotskoff, Grant M.; Vaikuntanathan, Suriyanarayanan; Geissler, Phillip L.
2014-10-24
In a stochastic heat engine driven by a cyclic non-equilibrium protocol, fluctuations in work and heat give rise to a fluctuating efficiency. Using computer simulations and tools from large deviation theory, we have examined these fluctuations in detail for a model two-state engine. We find in general that the form of efficiency probability distributions is similar to those described by Verley et al (2014 Nat. Commun. 5 4721), in particular featuring a local minimum in the long-time limit. In contrast to the time-symmetric engine protocols studied previously, however, this minimum need not occur at the value characteristic of a reversible Carnot engine. Furthermore, while the local minimum may reside at the global minimum of a large deviation rate function, it does not generally correspond to the least likely efficiency measured over finite time. Lastly, we introduce a general approximation for the finite-time efficiency distribution,more » $$P(\\eta )$$, based on large deviation statistics of work and heat, that remains very accurate even when $$P(\\eta )$$ deviates significantly from its large deviation form.« less
Efficiency and large deviations in time-asymmetric stochastic heat engines
Gingrich, Todd R.; Rotskoff, Grant M.; Vaikuntanathan, Suriyanarayanan; Geissler, Phillip L.
2014-10-24
In a stochastic heat engine driven by a cyclic non-equilibrium protocol, fluctuations in work and heat give rise to a fluctuating efficiency. Using computer simulations and tools from large deviation theory, we have examined these fluctuations in detail for a model two-state engine. We find in general that the form of efficiency probability distributions is similar to those described by Verley et al (2014 Nat. Commun. 5 4721), in particular featuring a local minimum in the long-time limit. In contrast to the time-symmetric engine protocols studied previously, however, this minimum need not occur at the value characteristic of a reversible Carnot engine. Furthermore, while the local minimum may reside at the global minimum of a large deviation rate function, it does not generally correspond to the least likely efficiency measured over finite time. Lastly, we introduce a general approximation for the finite-time efficiency distribution, $P(\\eta )$, based on large deviation statistics of work and heat, that remains very accurate even when $P(\\eta )$ deviates significantly from its large deviation form.
Large Deviations, Guerra's and A.S.S. Schemes, and the Parisi Hypothesis
NASA Astrophysics Data System (ADS)
Talagrand, Michel
2007-03-01
We investigate the problem of computing lim_{N to infty}1/aNlog EZ_N^a for any value of a, where Z N is the partition function of the celebrated Sherrington-Kirkpatrick (SK) model, or of some of its natural generalizations. This is a natural "large deviation" problem. Its study helps to get a fresh look at some of the recent ideas introduced in the area, and raises a number of natural questions. We provide a complete solution for a ≥ 0.
Multifractal analysis of the irregular set for almost-additive sequences via large deviations
NASA Astrophysics Data System (ADS)
Bomfim, Thiago; Varandas, Paulo
2015-10-01
In this paper we introduce a notion of free energy and large deviations rate function for asymptotically additive sequences of potentials via an approximation method by families of continuous potentials. We provide estimates for the topological pressure of the set of points whose non-additive sequences are far from the limit described through Kingman’s sub-additive ergodic theorem and give some applications in the context of Lyapunov exponents for diffeomorphisms and cocycles, and the Shannon-McMillan-Breiman theorem for Gibbs measures.
Quadratic and rate-independent limits for a large-deviations functional
NASA Astrophysics Data System (ADS)
Bonaschi, Giovanni A.; Peletier, Mark A.
2016-07-01
We construct a stochastic model showing the relationship between noise, gradient flows and rate-independent systems. The model consists of a one-dimensional birth-death process on a lattice, with rates derived from Kramers' law as an approximation of a Brownian motion on a wiggly energy landscape. Taking various limits, we show how to obtain a whole family of generalized gradient flows, ranging from quadratic to rate-independent ones, connected via ` L log L' gradient flows. This is achieved via Mosco-convergence of the renormalized large-deviations rate functional of the stochastic process.
Phase Diagram and Density Large Deviations of a Nonconserving ABC Model
NASA Astrophysics Data System (ADS)
Cohen, O.; Mukamel, D.
2012-02-01
The effect of particle-nonconserving processes on the steady state of driven diffusive systems is studied within the context of a generalized ABC model. It is shown that in the limit of slow nonconserving processes, the large deviation function of the overall particle density can be computed by making use of the steady-state density profile of the conserving model. In this limit one can define a chemical potential and identify first order transitions via Maxwell’s construction, similarly to what is done in equilibrium systems. This method may be applied to other driven models subjected to slow nonconserving dynamics.
A large deviation analysis on the near-equivalence between external and internal reservoirs
NASA Astrophysics Data System (ADS)
Medeiros, João R.; Duarte Queirós, Sílvio M.
2016-06-01
Within the spirit of van Kampen's "Langevin approach", we discuss the limits of validity of rephrasing the non-equilibrium problem of a particle subject to an external (work) reservoir-a system where the fluctuation-dissipation relation is not verified-into the simpler case with an internal (heat) reservoir for which the fluctuations and the dissipation arise from the same source. Using a convenient mapping of the thermomechanical parameters we show that, counter-intuitively, such approach is not only valid for steady state time independent quantities, but also for time dependent thermostatistical quantities, namely the injected and dissipated fluxes. We connect this result with the problem of large deviations and conclude that, in this context, we can only distinguish reservoirs by analysing the "fluctuations of accumulated fluctuations". As a by-product, we learn that the best reference approximation to the large deviation functions of a non-Markovian external reservoir system is not the respective internal reservoir limit-as often assumed and suggested by the Langevin approach-but its internal reservoir analogue system obtained from the mapping of the original thermomechanical parameters.
Level 2 and level 2.5 large deviation functionals for systems with and without detailed balance
NASA Astrophysics Data System (ADS)
Hoppenau, J.; Nickelsen, D.; Engel, A.
2016-08-01
Large deviation functions are an essential tool in the statistics of rare events. Often they can be obtained by contraction from a so-called level 2 or level 2.5 large deviation functional characterizing the empirical density and current of the underlying stochastic process. For Langevin systems obeying detailed balance, the explicit form of the level 2 functional has been known ever since the mathematical work of Donsker and Varadhan. We rederive the Donsker–Varadhan result using stochastic path-integrals. We than generalize the derivation to level 2.5 large deviation functionals for non-equilibrium steady states and elucidate the relation between the large deviation functionals and different notions of entropy production in stochastic thermodynamics. Finally, we discuss some aspects of the contractions to level 1 large deviation functions and illustrate our findings with examples.
NASA Astrophysics Data System (ADS)
Lopes, Artur O.; Neumann, Adriana
2015-05-01
In the present paper, we consider a family of continuous time symmetric random walks indexed by , . For each the matching random walk take values in the finite set of states ; notice that is a subset of , where is the unitary circle. The infinitesimal generator of such chain is denoted by . The stationary probability for such process converges to the uniform distribution on the circle, when . Here we want to study other natural measures, obtained via a limit on , that are concentrated on some points of . We will disturb this process by a potential and study for each the perturbed stationary measures of this new process when . We disturb the system considering a fixed potential and we will denote by the restriction of to . Then, we define a non-stochastic semigroup generated by the matrix , where is the infinifesimal generator of . From the continuous time Perron's Theorem one can normalized such semigroup, and, then we get another stochastic semigroup which generates a continuous time Markov Chain taking values on . This new chain is called the continuous time Gibbs state associated to the potential , see (Lopes et al. in J Stat Phys 152:894-933, 2013). The stationary probability vector for such Markov Chain is denoted by . We assume that the maximum of is attained in a unique point of , and from this will follow that . Thus, here, our main goal is to analyze the large deviation principle for the family , when . The deviation function , which is defined on , will be obtained from a procedure based on fixed points of the Lax-Oleinik operator and Aubry-Mather theory. In order to obtain the associated Lax-Oleinik operator we use the Varadhan's Lemma for the process . For a careful analysis of the problem we present full details of the proof of the Large Deviation Principle, in the Skorohod space, for such family of Markov Chains, when . Finally, we compute the entropy of the invariant probabilities on the Skorohod space associated to the Markov Chains we analyze.
Topology Trivialization and Large Deviations for the Minimum in the Simplest Random Optimization
NASA Astrophysics Data System (ADS)
Fyodorov, Yan V.; Le Doussal, Pierre
2013-09-01
Finding the global minimum of a cost function given by the sum of a quadratic and a linear form in N real variables over (N-1)-dimensional sphere is one of the simplest, yet paradigmatic problems in Optimization Theory known as the "trust region subproblem" or "constraint least square problem". When both terms in the cost function are random this amounts to studying the ground state energy of the simplest spherical spin glass in a random magnetic field. We first identify and study two distinct large-N scaling regimes in which the linear term (magnetic field) leads to a gradual topology trivialization, i.e. reduction in the total number {N}_{tot} of critical (stationary) points in the cost function landscape. In the first regime {N}_{tot} remains of the order N and the cost function (energy) has generically two almost degenerate minima with the Tracy-Widom (TW) statistics. In the second regime the number of critical points is of the order of unity with a finite probability for a single minimum. In that case the mean total number of extrema (minima and maxima) of the cost function is given by the Laplace transform of the TW density, and the distribution of the global minimum energy is expected to take a universal scaling form generalizing the TW law. Though the full form of that distribution is not yet known to us, one of its far tails can be inferred from the large deviation theory for the global minimum. In the rest of the paper we show how to use the replica method to obtain the probability density of the minimum energy in the large-deviation approximation by finding both the rate function and the leading pre-exponential factor.
Large Deviations of Radial Statistics in the Two-Dimensional One-Component Plasma
NASA Astrophysics Data System (ADS)
Cunden, Fabio Deelan; Mezzadri, Francesco; Vivo, Pierpaolo
2016-07-01
The two-dimensional one-component plasma is an ubiquitous model for several vortex systems. For special values of the coupling constant β q^2 (where q is the particles charge and β the inverse temperature), the model also corresponds to the eigenvalues distribution of normal matrix models. Several features of the system are discussed in the limit of large number N of particles for generic values of the coupling constant. We show that the statistics of a class of radial observables produces a rich phase diagram, and their asymptotic behaviour in terms of large deviation functions is calculated explicitly, including next-to-leading terms up to order 1 / N. We demonstrate a split-off phenomenon associated to atypical fluctuations of the edge density profile. We also show explicitly that a failure of the fluid phase assumption of the plasma can break a genuine 1 / N-expansion of the free energy. Our findings are corroborated by numerical comparisons with exact finite-N formulae valid for β q^2=2.
Heterogeneity-induced large deviations in activity and (in some cases) entropy production
NASA Astrophysics Data System (ADS)
Gingrich, Todd R.; Vaikuntanathan, Suriyanarayanan; Geissler, Phillip L.
2014-10-01
We solve a simple model that supports a dynamic phase transition and show conditions for the existence of the transition. Using methods of large deviation theory we analytically compute the probability distribution for activity and entropy production rates of the trajectories on a large ring with a single heterogeneous link. The corresponding joint rate function demonstrates two dynamical phases—one localized and the other delocalized, but the marginal rate functions do not always exhibit the underlying transition. Symmetries in dynamic order parameters influence the observation of a transition, such that distributions for certain dynamic order parameters need not reveal an underlying dynamical bistability. Solution of our model system furthermore yields the form of the effective Markov transition matrices that generate dynamics in which the two dynamical phases are at coexistence. We discuss the implications of the transition for the response of bacterial cells to antibiotic treatment, arguing that even simple models of a cell cycle lacking an explicit bistability in configuration space will exhibit a bistability of dynamical phases.
Large Deviations of Radial Statistics in the Two-Dimensional One-Component Plasma
NASA Astrophysics Data System (ADS)
Cunden, Fabio Deelan; Mezzadri, Francesco; Vivo, Pierpaolo
2016-09-01
The two-dimensional one-component plasma is an ubiquitous model for several vortex systems. For special values of the coupling constant β q^2 (where q is the particles charge and β the inverse temperature), the model also corresponds to the eigenvalues distribution of normal matrix models. Several features of the system are discussed in the limit of large number N of particles for generic values of the coupling constant. We show that the statistics of a class of radial observables produces a rich phase diagram, and their asymptotic behaviour in terms of large deviation functions is calculated explicitly, including next-to-leading terms up to order 1 / N. We demonstrate a split-off phenomenon associated to atypical fluctuations of the edge density profile. We also show explicitly that a failure of the fluid phase assumption of the plasma can break a genuine 1 / N-expansion of the free energy. Our findings are corroborated by numerical comparisons with exact finite- N formulae valid for β q^2=2.
Large-deviation joint statistics of the finite-time Lyapunov spectrum in isotropic turbulence
NASA Astrophysics Data System (ADS)
Johnson, Perry L.; Meneveau, Charles
2015-08-01
One of the hallmarks of turbulent flows is the chaotic behavior of fluid particle paths with exponentially growing separation among them while their distance does not exceed the viscous range. The maximal (positive) Lyapunov exponent represents the average strength of the exponential growth rate, while fluctuations in the rate of growth are characterized by the finite-time Lyapunov exponents (FTLEs). In the last decade or so, the notion of Lagrangian coherent structures (which are often computed using FTLEs) has gained attention as a tool for visualizing coherent trajectory patterns in a flow and distinguishing regions of the flow with different mixing properties. A quantitative statistical characterization of FTLEs can be accomplished using the statistical theory of large deviations, based on the so-called Cramér function. To obtain the Cramér function from data, we use both the method based on measuring moments and measuring histograms and introduce a finite-size correction to the histogram-based method. We generalize the existing univariate formalism to the joint distributions of the two FTLEs needed to fully specify the Lyapunov spectrum in 3D flows. The joint Cramér function of turbulence is measured from two direct numerical simulation datasets of isotropic turbulence. Results are compared with joint statistics of FTLEs computed using only the symmetric part of the velocity gradient tensor, as well as with joint statistics of instantaneous strain-rate eigenvalues. When using only the strain contribution of the velocity gradient, the maximal FTLE nearly doubles in magnitude, highlighting the role of rotation in de-correlating the fluid deformations along particle paths. We also extend the large-deviation theory to study the statistics of the ratio of FTLEs. The most likely ratio of the FTLEs λ1 : λ2 : λ3 is shown to be about 4:1:-5, compared to about 8:3:-11 when using only the strain-rate tensor for calculating fluid volume deformations. The results
Large-deviation joint statistics of the finite-time Lyapunov spectrum in isotropic turbulence
Johnson, Perry L. Meneveau, Charles
2015-08-15
One of the hallmarks of turbulent flows is the chaotic behavior of fluid particle paths with exponentially growing separation among them while their distance does not exceed the viscous range. The maximal (positive) Lyapunov exponent represents the average strength of the exponential growth rate, while fluctuations in the rate of growth are characterized by the finite-time Lyapunov exponents (FTLEs). In the last decade or so, the notion of Lagrangian coherent structures (which are often computed using FTLEs) has gained attention as a tool for visualizing coherent trajectory patterns in a flow and distinguishing regions of the flow with different mixing properties. A quantitative statistical characterization of FTLEs can be accomplished using the statistical theory of large deviations, based on the so-called Cramér function. To obtain the Cramér function from data, we use both the method based on measuring moments and measuring histograms and introduce a finite-size correction to the histogram-based method. We generalize the existing univariate formalism to the joint distributions of the two FTLEs needed to fully specify the Lyapunov spectrum in 3D flows. The joint Cramér function of turbulence is measured from two direct numerical simulation datasets of isotropic turbulence. Results are compared with joint statistics of FTLEs computed using only the symmetric part of the velocity gradient tensor, as well as with joint statistics of instantaneous strain-rate eigenvalues. When using only the strain contribution of the velocity gradient, the maximal FTLE nearly doubles in magnitude, highlighting the role of rotation in de-correlating the fluid deformations along particle paths. We also extend the large-deviation theory to study the statistics of the ratio of FTLEs. The most likely ratio of the FTLEs λ{sub 1} : λ{sub 2} : λ{sub 3} is shown to be about 4:1:−5, compared to about 8:3:−11 when using only the strain-rate tensor for calculating fluid volume
The large deviations of the whitening process in random constraint satisfaction problems
NASA Astrophysics Data System (ADS)
Braunstein, Alfredo; Dall’Asta, Luca; Semerjian, Guilhem; Zdeborová, Lenka
2016-05-01
Random constraint satisfaction problems undergo several phase transitions as the ratio between the number of constraints and the number of variables is varied. When this ratio exceeds the satisfiability threshold no more solutions exist; the satisfiable phase, for less constrained problems, is itself divided in an unclustered regime and a clustered one. In the latter solutions are grouped in clusters of nearby solutions separated in configuration space from solutions of other clusters. In addition the rigidity transition signals the appearance of so-called frozen variables in typical solutions: beyond this threshold most solutions belong to clusters with an extensive number of variables taking the same values in all solutions of the cluster. In this paper we refine the description of this phenomenon by estimating the location of the freezing transition, corresponding to the disappearance of all unfrozen solutions (not only typical ones). We also unveil phase transitions for the existence and uniqueness of locked solutions, in which all variables are frozen. From a technical point of view we characterize atypical solutions with a number of frozen variables different from the typical value via a large deviation study of the dynamics of a stripping process (whitening) that unveils the frozen variables of a solution, building upon recent works on atypical trajectories of the bootstrap percolation dynamics. Our results also bear some relevance from an algorithmic perspective, previous numerical studies having shown that heuristic algorithms of various kinds usually output unfrozen solutions.
NASA Astrophysics Data System (ADS)
Lopes, Artur; Neumann, Adriana; Thieullen, Philippe
2013-09-01
Through this paper we analyze the ergodic properties of continuous time Markov chains with values on the one-dimensional spin lattice (also known as the Bernoulli space). Initially, we consider as the infinitesimal generator the operator [InlineEquation not available: see fulltext.], where [InlineEquation not available: see fulltext.] is a discrete time Ruelle operator (transfer operator), and is a given fixed Lipschitz function. The associated continuous time stationary Markov chain will define the a priori probability. Given a Lipschitz interaction , we are interested in Gibbs (equilibrium) state for such V. This will be another continuous time stationary Markov chain. In order to analyze this problem we will use a continuous time Ruelle operator (transfer operator) naturally associated to V. Among other things we will show that a continuous time Perron-Frobenius Theorem is true in the case V is a Lipschitz function. We also introduce an entropy, which is negative (see also Lopes et al. in Entropy and Variational Principle for one-dimensional Lattice Systems with a general a-priori probability: positive and zero temperature. Arxiv, 2012), and we consider a variational principle of pressure. Finally, we analyze large deviations properties for the empirical measure in the continuous time setting using results by Y. Kifer (Tamsui Oxf. J. Manag. Sci. 321(2):505-524, 1990). In the last appendix of the paper we explain why the techniques we develop here have the capability to be applied to the analysis of convergence of a certain version of the Metropolis algorithm.
Simulation of heat waves in climate models using large deviation algorithms
NASA Astrophysics Data System (ADS)
Ragone, Francesco; Bouchet, Freddy; Wouters, Jeroen
2016-04-01
One of the goals of climate science is to characterize the statistics of extreme, potentially dangerous events (e.g. exceptionally intense precipitations, wind gusts, heat waves) in the present and future climate. The study of extremes is however hindered by both a lack of past observational data for events with a return time larger than decades or centuries, and by the large computational cost required to perform a proper sampling of extreme statistics with state of the art climate models. The study of the dynamics leading to extreme events is especially difficult as it requires hundreds or thousands of realizations of the dynamical paths leading to similar extremes. We will discuss here a new numerical algorithm, based on large deviation theory, that allows to efficiently sample very rare events in complex climate models. A large ensemble of realizations are run in parallel, and selection and cloning procedures are applied in order to oversample the trajectories leading to the extremes of interest. The statistics and characteristic dynamics of the extremes can then be computed on a much larger sample of events. This kind of importance sampling method belongs to a class of genetic algorithms that have been successfully applied in other scientific fields (statistical mechanics, complex biomolecular dynamics), allowing to decrease by orders of magnitude the numerical cost required to sample extremes with respect to standard direct numerical sampling. We study the applicability of this method to the computation of the statistics of European surface temperatures with the Planet Simulator (Plasim), an intermediate complexity general circulation model of the atmosphere. We demonstrate the efficiency of the method by comparing its performances against standard approaches. Dynamical paths leading to heat waves are studied, enlightening the relation of Plasim heat waves with blocking events, and the dynamics leading to these events. We then discuss the feasibility of this
Mechanical principles of large mirror supports
NASA Astrophysics Data System (ADS)
Kärcher, Hans J.; Eisenträger, Peter; Süss, Martin
2010-07-01
Large thin meniscus mirrors use force-controlled shape actuators to obtain the required optical performance. The shape actuators can be interpreted as an advancement of classical mirror supports as whiffle trees or iso-static levers, which worked purely mechanical. The paper develops, after a short historical overview, the theoretical background of mirror mechanics. Different combinations of force-controlled shape actuators with mechanical, hydraulic or pneumatic whiffle trees or iso-static levers are analyzed in regard of their impact on optical performance, dynamic and control behavior. The investigations were the basis for the choice of the shape actuator system for the E-ELT M2, executed by MT Mechatronics under an ESO contract in 2008-09.
Unification of Small and Large Time Scales for Biological Evolution: Deviations from Power Law
NASA Astrophysics Data System (ADS)
Chowdhury, Debashish; Stauffer, Dietrich; Kunwar, Ambarish
2003-02-01
We develop a unified model that describes both “micro” and “macro” evolutions within a single theoretical framework. The ecosystem is described as a dynamic network; the population dynamics at each node of this network describes the “microevolution” over ecological time scales (i.e., birth, ageing, and natural death of individual organisms), while the appearance of new nodes, the slow changes of the links, and the disappearance of existing nodes accounts for the “macroevolution” over geological time scales (i.e., the origination, evolution, and extinction of species). In contrast to several earlier claims in the literature, we observe strong deviations from power law in the regime of long lifetimes.
NASA Astrophysics Data System (ADS)
Itami, Masato; Sasa, Shin-ichi
2015-11-01
We study the friction coefficient of a macroscopic sphere in a viscous fluid at low Reynolds number. First, Kirkwood's formula for the friction coefficient is reviewed on the basis of the Hamiltonian description of particle systems. According to this formula, the friction coefficient is expressed in terms of the stress correlation on the surface of the macroscopic sphere. Then, with the aid of large deviation theory, we relate the surface stress correlation to the stress correlation in the bulk of the fluid, where the latter is characterized by the viscosity in the Green-Kubo formula. By combining Kirkwood's formula and the Green-Kubo formula in large deviation theory, we derive Stokes' law without explicitly employing the hydrodynamic equations.
Extending the Principles of Intensive Writing to Large Macroeconomics Classes
ERIC Educational Resources Information Center
Docherty, Peter; Tse, Harry; Forman, Ross; McKenzie, Jo
2010-01-01
The authors report on the design and implementation of a pilot program to extend the principles of intensive writing outlined by W. Lee Hansen (1998), Murray S. Simpson and Shireen E. Carroll (1999) and David Carless (2006) to large macroeconomics classes. The key aspect of this program was its collaborative nature, with staff from two specialist…
NASA Astrophysics Data System (ADS)
Akbari, M. R.; Nimafar, M.; Ganji, D. D.; Akbarzade, M. M.
2014-12-01
The kinematic assumptions upon which the Euler-Bernoulli beam theory is founded allow it to be extended to more advanced analysis. Simple superposition allows for three-dimensional transverse loading. Using alternative constitutive equations can allow for viscoelastic or plastic beam deformation. Euler-Bernoulli beam theory can also be extended to the analysis of curved beams, beam buckling, composite beams and geometrically nonlinear beam deflection. In this study, solving the nonlinear differential equation governing the calculation of the large rotation deviation of the beam (or column) has been discussed. Previously to calculate the rotational deviation of the beam, the assumption is made that the angular deviation of the beam is small. By considering the small slope in the linearization of the governing differential equation, the solving is easy. The result of this simplification in some cases will lead to an excessive error. In this paper nonlinear differential equations governing on this system are solved analytically by Akbari-Ganji's method (AGM). Moreover, in AGM by solving a set of algebraic equations, complicated nonlinear equations can easily be solved and without any mathematical operations such as integration solving. The solution of the problem can be obtained very simply and easily. Furthermore, to enhance the accuracy of the results, the Taylor expansion is not needed in most cases via AGM manner. Also, comparisons are made between AGM and numerical method (Runge-Kutta 4th). The results reveal that this method is very effective and simple, and can be applied for other nonlinear problems.
Deviations from the fundamental plane of early-type galaxies and large-scale cluster motions
NASA Astrophysics Data System (ADS)
Gibbons, Rachel Annette
2002-11-01
We fit the fundamental plane, FP, to over 400 early-type galaxies in 20 nearby clusters with cz ˜ 4000 11000 km s -1 using our own photometry and spectroscopy its well as measurements culled from the literature. We find that the duality-of- fit, rms(log σ), to the average fundamental plane,
Large aperture spatial heterodyne imaging spectrometer: Principle and experimental results
NASA Astrophysics Data System (ADS)
Xiangli, Bin; Cai, Qisheng; Du, Shusong
2015-12-01
A large aperture spatial heterodyne imaging spectrometer (LASHIS) is proposed. It is a kind of pushbroom Fourier transform ultraspectral imager with no moving parts. This imaging spectrometer, based on a Sagnac lateral shearing interferometer combined with a pair of gratings, has the advantages of high spectral resolution, high throughput and robustness. The principle of LASHIS and its spectral retrieval method are introduced. The processing chain to convert raw images to ultraspectral datacube is also described. Experimental results demonstrate the high resolving power of LASHIS with the emission spectrum of a low pressure sodium lamp.
... only when he or she also has a "cold" (an upper respiratory tract infection). In these individuals, ... problems related to the deviated septum. Once the "cold" resolves, and the nasal inflammation subsides, symptoms of ...
Peletier, Mark A.; Redig, Frank; Vafayi, Kiamars
2014-09-01
We consider three one-dimensional continuous-time Markov processes on a lattice, each of which models the conduction of heat: the family of Brownian Energy Processes with parameter m (BEP(m)), a Generalized Brownian Energy Process, and the Kipnis-Marchioro-Presutti (KMP) process. The hydrodynamic limit of each of these three processes is a parabolic equation, the linear heat equation in the case of the BEP(m) and the KMP, and a nonlinear heat equation for the Generalized Brownian Energy Process with parameter a (GBEP(a)). We prove the hydrodynamic limit rigorously for the BEP(m), and give a formal derivation for the GBEP(a). We then formally derive the pathwise large-deviation rate functional for the empirical measure of the three processes. These rate functionals imply gradient-flow structures for the limiting linear and nonlinear heat equations. We contrast these gradient-flow structures with those for processes describing the diffusion of mass, most importantly the class of Wasserstein gradient-flow systems. The linear and nonlinear heat-equation gradient-flow structures are each driven by entropy terms of the form -log ρ; they involve dissipation or mobility terms of order ρ² for the linear heat equation, and a nonlinear function of ρ for the nonlinear heat equation.
Hurtado, Pablo I; Garrido, Pedro L
2010-04-01
Most systems, when pushed out of equilibrium, respond by building up currents of locally conserved observables. Understanding how microscopic dynamics determines the averages and fluctuations of these currents is one of the main open problems in nonequilibrium statistical physics. The additivity principle is a theoretical proposal that allows to compute the current distribution in many one-dimensional nonequilibrium systems. Using simulations, we validate this conjecture in a simple and general model of energy transport, both in the presence of a temperature gradient and in canonical equilibrium. In particular, we show that the current distribution displays a Gaussian regime for small current fluctuations, as prescribed by the central limit theorem, and non-Gaussian (exponential) tails for large current deviations, obeying in all cases the Gallavotti-Cohen fluctuation theorem. In order to facilitate a given current fluctuation, the system adopts a well-defined temperature profile different from that of the steady state and in accordance with the additivity hypothesis predictions. System statistics during a large current fluctuation is independent of the sign of the current, which implies that the optimal profile (as well as higher-order profiles and spatial correlations) are invariant upon current inversion. We also demonstrate that finite-time joint fluctuations of the current and the profile are well described by the additivity functional. These results suggest the additivity hypothesis as a general and powerful tool to compute current distributions in many nonequilibrium systems. PMID:20481672
Large impurity effects in rubrene crystals: First-principles calculations
Tsetseris, L.; Pantelides, Sokrates T.
2008-01-01
Carrier mobilities of rubrene films are among the highest values reported for any organic semiconductor. Here, we probe with first-principles calculations the sensitivity of rubrene crystals on impurities. We find that isolated oxygen impurities create distinct peaks in the electronic density of states consistent with observations of defect levels in rubrene and that increased O content changes the position and shape of rubrene energy bands significantly. We also establish a dual role of hydrogen as individual H species and H impurity pairs create and annihilate deep carrier traps, respectively. The results are relevant to the performance and reliability of rubrene-based devices.
Large vs. Small Lectures in the Principles Course: The Dilemma of the Small Department.
ERIC Educational Resources Information Center
Adams, Curtis H.; Britton, Charles R.
Research results show that there is little loss in student productivity when changing from small lecture classes to large sections in principles of economics courses. A large lecture section of a college level principles of economics course with undergraduate tutors providing personal assistance to students was compared with six classes of 35 to…
Dupuis, Paul
2014-03-14
This proposal is concerned with applications of Monte Carlo to problems in physics and chemistry where rare events degrade the performance of standard Monte Carlo. One class of problems is concerned with computation of various aspects of the equilibrium behavior of some Markov process via time averages. The problem to be overcome is that rare events interfere with the efficient sampling of all relevant parts of phase space. A second class concerns sampling transitions between two or more stable attractors. Here, rare events do not interfere with the sampling of all relevant parts of phase space, but make Monte Carlo inefficient because of the very large number of samples required to obtain variance comparable to the quantity estimated. The project uses large deviation methods for the mathematical analyses of various Monte Carlo techniques, and in particular for algorithmic analysis and design. This is done in the context of relevant application areas, mainly from chemistry and biology.
Bioinspired Principles for Large-Scale Networked Sensor Systems: An Overview
Jacobsen, Rune Hylsberg; Zhang, Qi; Toftegaard, Thomas Skjødeberg
2011-01-01
Biology has often been used as a source of inspiration in computer science and engineering. Bioinspired principles have found their way into network node design and research due to the appealing analogies between biological systems and large networks of small sensors. This paper provides an overview of bioinspired principles and methods such as swarm intelligence, natural time synchronization, artificial immune system and intercellular information exchange applicable for sensor network design. Bioinspired principles and methods are discussed in the context of routing, clustering, time synchronization, optimal node deployment, localization and security and privacy. PMID:22163841
NASA Astrophysics Data System (ADS)
Rosi, G. A.; la Bastide, B.; Gaebler, J.; Kinzel, M.; Rival, D. E.
2014-12-01
The following study proposes a two-dimensional large-scale particle tracking velocimetry (LS-PTV) system to characterize coherent wind structures. Seven minutes of LS-PTV data is collected via an apparatus that seeds fog-filled soap bubbles into the wind at a height of 6m from the ground. The LS-PTV data is compared to 20 minutes of data collected concurrently from a wind mast at the same site. The LS-PTV system recorded a mean streamwise velocity of 1.35m/s with a standard deviation of 0.23m/s at a mean height of 2.50m with a standard deviation of 0.7m, which agrees well with the velocity profile measured by the wind mast. Furthermore, the Reynolds stresses measured by the LS-PTV system are found to compare to those measured by the wind mast and by Klebanoff [1] for a canonical turbulent boundary layer. The current study assumes that the centre-of-curvature trajectories of the particle pathlines are representative of the trajectories followed by the spanwise vortices. As a proof-of-principle study, this work has been successful in accurately describing the vortex distribution very near to the ground. However, the trajectories followed by the centres-of- curvat.ure belonging to pathlines concurrently passing through the field-of-view were sporadic and uncorrelated.
Coarse Grained Approach to First Principles Modeling of Radiation Cascade in Large Fe Supercells
NASA Astrophysics Data System (ADS)
Odbadrakh, Kh; Nicholson, D. M.; Rusanu, A.; Samolyuk, G. D.; Stoller, R. E.; Zhang, X.-G.; Stocks, G. M.
2012-12-01
Classical Molecular Dynamics (MD) simulations characterizing dislocations and radiation damage typically treat 105-107 atoms. First principles techniques employed to understand systems at an atomistic level are not practical for such large systems consisting of millions of atoms. We present an efficient coarse grained (CG) approach to calculate local electronic and magnetic properties of large MD-generated structures from the first principles. Local atomic magnetic moments in crystalline Fe are perturbed by the presence of radiation generated vacancies and interstitials. The effects are most pronounced near the defect cores and decay slowly as the strain field of the defects decrease with distance. We develop the CG technique based on the Locally Self-consistent Multiple Scattering (LSMS) method that exploits the near-sightedness of the electron Green function. The atomic positions were determined by MD with an embedded atom force field. The local moments in the neighborhood of the defect cores are calculated with first-principles based on full local structure information. Atoms in the rest of the system are modeled by representative atoms with approximated properties. The calculations result in local moments near the defect centers with first-principles accuracy, while capturing coarse-grained details of local moments at greater length scales. This CG approach makes these large scale structures amenable to first principles study.
Implementing the "Marketing You" Project in Large Sections of Principles of Marketing
ERIC Educational Resources Information Center
Smith, Karen H.
2004-01-01
There is mounting pressure on business education to increase experiential learning at the same time that budget constraints are forcing universities to increase class size. This article explains the design and implementation of the "Marketing You" project in two large sections of Principles of Marketing to bring experiential learning into the…
NASA Astrophysics Data System (ADS)
Jauregui, Max; Tsallis, Constantino
2015-02-01
We consider correlated random variables X1, …, Xn taking values in {0, 1} such that, for any permutation π of {1, …, n}, the random vectors (X1, …, Xn) and (Xπ(1), …, Xπ(n)) have the same distribution. This distribution, which was introduced by Rodríguez et al. [J. Stat. Mech. 2008, P09006] and then generalized by Hanel et al. [Eur. Phys. J. B 72, 263 (2009)], is scale-invariant and depends on a real parameter ν > 0 (ν → ∞ implies independence). Putting Sn = X1 + ⋯ + Xn, the distribution of Sn - n/2 approaches a Q-Gaussian distribution with compact support (Q = 1 - 1/(ν - 1) < 1) as n increases, after appropriate scaling. In the present article, we show that the distribution of Sn/n converges, as n → ∞, to a beta distribution with both parameters equal to ν. In particular, the law of large numbers does not hold since, if 0 ≤ x < 1/2, then ℙ(Sn/n ≤ x), which is the probability of the event {Sn/n ≤ x} (large deviation), does not converge to zero as n → ∞. For x = 0 and every real ν > 0, we show that ℙ(Sn = 0) decays to zero like a power law of the form 1/nν with a subdominant term of the form 1/nν+1. If 0 < x ≤ 1 and ν > 0 is an integer, we show that we can analytically find upper and lower bounds for the difference between ℙ(Sn/n ≤ x) and its (n → ∞) limit. We also show that these bounds vanish like a power law of the form 1/n with a subdominant term of the form 1/n2.
On Large Time Behavior and Selection Principle for a Diffusive Carr-Penrose Model
NASA Astrophysics Data System (ADS)
Conlon, Joseph G.; Dabkowski, Michael; Wu, Jingchen
2016-04-01
This paper is concerned with the study of a diffusive perturbation of the linear LSW model introduced by Carr and Penrose. A main subject of interest is to understand how the presence of diffusion acts as a selection principle, which singles out a particular self-similar solution of the linear LSW model as determining the large time behavior of the diffusive model. A selection principle is rigorously proven for a model which is a semiclassical approximation to the diffusive model. Upper bounds on the rate of coarsening are also obtained for the full diffusive model.
Dissociated Vertical Deviation
... Eye Terms Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Dissociated Vertical Deviation En Español Read in Chinese What is Dissociated Vertical Deviation (DVD)? DVD is ...
Fattebert, Jean-Luc; Lau, Edmond Y.; Bennion, Brian J.; Huang, Patrick; Lightstone, Felice C.
2015-10-22
Enzymes are complicated solvated systems that typically require many atoms to simulate their function with any degree of accuracy. We have recently developed numerical techniques for large scale First-Principles molecular dynamics simulations and applied them to study the enzymatic reaction catalyzed by acetylcholinesterase. We carried out Density functional theory calculations for a quantum mechanical (QM) sub- system consisting of 612 atoms with an O(N) complexity finite-difference approach. The QM sub-system is embedded inside an external potential field representing the electrostatic effect due to the environment. We obtained finite temperature sampling by First-Principles molecular dynamics for the acylation reaction of acetylcholinemore » catalyzed by acetylcholinesterase. Our calculations shows two energies barriers along the reaction coordinate for the enzyme catalyzed acylation of acetylcholine. In conclusion, the second barrier (8.5 kcal/mole) is rate-limiting for the acylation reaction and in good agreement with experiment.« less
Fattebert, Jean-Luc; Lau, Edmond Y.; Bennion, Brian J.; Huang, Patrick; Lightstone, Felice C.
2015-10-22
Enzymes are complicated solvated systems that typically require many atoms to simulate their function with any degree of accuracy. We have recently developed numerical techniques for large scale First-Principles molecular dynamics simulations and applied them to study the enzymatic reaction catalyzed by acetylcholinesterase. We carried out Density functional theory calculations for a quantum mechanical (QM) sub- system consisting of 612 atoms with an O(N) complexity finite-difference approach. The QM sub-system is embedded inside an external potential field representing the electrostatic effect due to the environment. We obtained finite temperature sampling by First-Principles molecular dynamics for the acylation reaction of acetylcholine catalyzed by acetylcholinesterase. Our calculations shows two energies barriers along the reaction coordinate for the enzyme catalyzed acylation of acetylcholine. In conclusion, the second barrier (8.5 kcal/mole) is rate-limiting for the acylation reaction and in good agreement with experiment.
NASA Technical Reports Server (NTRS)
Smith, Terence R.; Menon, Sudhakar; Star, Jeffrey L.; Estes, John E.
1987-01-01
This paper provides a brief survey of the history, structure and functions of 'traditional' geographic information systems (GIS), and then suggests a set of requirements that large-scale GIS should satisfy, together with a set of principles for their satisfaction. These principles, which include the systematic application of techniques from several subfields of computer science to the design and implementation of GIS and the integration of techniques from computer vision and image processing into standard GIS technology, are discussed in some detail. In particular, the paper provides a detailed discussion of questions relating to appropriate data models, data structures and computational procedures for the efficient storage, retrieval and analysis of spatially-indexed data.
Large-scale brain networks in cognition: emerging methods and principles.
Bressler, Steven L; Menon, Vinod
2010-06-01
An understanding of how the human brain produces cognition ultimately depends on knowledge of large-scale brain organization. Although it has long been assumed that cognitive functions are attributable to the isolated operations of single brain areas, we demonstrate that the weight of evidence has now shifted in support of the view that cognition results from the dynamic interactions of distributed brain areas operating in large-scale networks. We review current research on structural and functional brain organization, and argue that the emerging science of large-scale brain networks provides a coherent framework for understanding of cognition. Critically, this framework allows a principled exploration of how cognitive functions emerge from, and are constrained by, core structural and functional networks of the brain. PMID:20493761
Thermal Conductivity and Large Isotope Effect in GaN from First Principles
Lindsay, L.; Broido, D. A.; Reinecke, T. L.
2012-08-28
We present atomistic first principles results for the lattice thermal conductivity of GaN and compare them to those for GaP, GaAs, and GaSb. In GaN we find a large increase to the thermal conductivity with isotopic enrichment, ~65% at room temperature. We show that both the high thermal conductivity and its enhancement with isotopic enrichment in GaN arise from the weak coupling of heat-carrying acoustic phonons with optic phonons. This weak scattering results from stiff atomic bonds and the large Ga to N mass ratio, which give phonons high frequencies and also a pronounced energy gap between acoustic and optic phonons compared to other materials. Rigorous understanding of these features in GaN gives important insights into the interplay between intrinsic phonon-phonon scattering and isotopic scattering in a range of materials.
The Force-From-Lipid (FFL) principle of mechanosensitivity, at large and in elements
Teng, Jinfeng; Loukin, Stephen; Anishkin, Andriy; Kung, Ching
2014-01-01
Focus on touch and hearing distracts attention from numerous subconscious force sensors such as the vital control of blood pressure, systemic osmolarity, etc. and sensors in non-animals. Multifarious manifestations should not obscure invariant and fundamental physico-chemical principles. We advocate that force-from-lipid (FFL) is one such principle. It is based on the fact that the self-assembled bilayer necessitates inherent forces that are large, and anisotropic, even at life’s origin. Functional response of membrane proteins is governed by bilayer-force changes. Added stress can redirect these forces, leading to geometric changes of embedded proteins such as ion channels. The FFL principle was first demonstrated when purified bacterial MscL remained mechanosensitive (MS) after reconstituting into bilayers. This key experiment has recently been unequivocally replicated with two vertebrate MS K2p channels. Even the canonical Kv and the Drosophila TRPCs have now been shown to be MS in biophysical and in physiological contexts, supporting the universality of the FFL paradigm. We also review the deterministic role of mechanical force during stem-cell differentiation as well as the cell-cell and cell-matrix tethers that provide force communications. In both the ear hair cell and the worm’s touch neuron, deleting the cadherin or microtubule tethers reduces but does not eliminate MS-channel activities. We found no evidence to distinguish whether these tethers directly pulls on the channel protein or a surrounding lipid platform. Regardless of the implementation, pulling tether tenses up the bilayer. Membrane tenting is directly visible at the apexes of the stereocilia. PMID:24888690
Jump rates for surface diffusion of large molecules from first principles
Shea, Patrick Kreuzer, Hans Jürgen
2015-04-21
We apply a recently developed stochastic model for the surface diffusion of large molecules to calculate jump rates for 9,10-dithioanthracene on a Cu(111) surface. The necessary input parameters for the stochastic model are calculated from first principles using density functional theory (DFT). We find that the inclusion of van der Waals corrections to the DFT energies is critical to obtain good agreement with experimental results for the adsorption geometry and energy barrier for diffusion. The predictions for jump rates in our model are in excellent agreement with measured values and show a marked improvement over transition state theory (TST). We find that the jump rate prefactor is reduced by an order of magnitude from the TST estimate due to frictional damping resulting from energy exchange with surface phonons, as well as a rotational mode of the diffusing molecule.
Creminelli, Paolo; Gleyzes, Jérôme; Vernizzi, Filippo; Hui, Lam; Simonović, Marko E-mail: jerome.gleyzes@cea.fr E-mail: msimonov@sissa.it
2014-06-01
The recently derived consistency relations for Large Scale Structure do not hold if the Equivalence Principle (EP) is violated. We show it explicitly in a toy model with two fluids, one of which is coupled to a fifth force. We explore the constraints that galaxy surveys can set on EP violation looking at the squeezed limit of the 3-point function involving two populations of objects. We find that one can explore EP violations of order 10{sup −3}÷10{sup −4} on cosmological scales. Chameleon models are already very constrained by the requirement of screening within the Solar System and only a very tiny region of the parameter space can be explored with this method. We show that no violation of the consistency relations is expected in Galileon models.
Integration of human factors principles in LARG organizations--a conceptual model.
Figueira, Sara; Machado, V Cruz; Nunes, Isabel L
2012-01-01
Nowadays many companies are undergoing organizational transformations in order to meet the changing market demands. Thus, in order to become more competitive, supply chains (SC) are adopting new management paradigms to improve SC performance: lean, agile, resilient and green (LARG paradigms). The implementation of new production paradigms demands particular care with the issues related with Human Factors to avoid health and safety problems to workers and losses to companies. Thus, the successful introduction of these new production paradigms depends among others on a Human Factors oriented approach. This work presents a conceptual framework that allows integrating ergonomic and safety design principles during the different implementation phases of lean, agile, resilient and green practices. PMID:22316960
A method of orbital analysis for large-scale first-principles simulations
Ohwaki, Tsukuru; Otani, Minoru; Ozaki, Taisuke
2014-06-28
An efficient method of calculating the natural bond orbitals (NBOs) based on a truncation of the entire density matrix of a whole system is presented for large-scale density functional theory calculations. The method recovers an orbital picture for O(N) electronic structure methods which directly evaluate the density matrix without using Kohn-Sham orbitals, thus enabling quantitative analysis of chemical reactions in large-scale systems in the language of localized Lewis-type chemical bonds. With the density matrix calculated by either an exact diagonalization or O(N) method, the computational cost is O(1) for the calculation of NBOs associated with a local region where a chemical reaction takes place. As an illustration of the method, we demonstrate how an electronic structure in a local region of interest can be analyzed by NBOs in a large-scale first-principles molecular dynamics simulation for a liquid electrolyte bulk model (propylene carbonate + LiBF{sub 4})
NASA Astrophysics Data System (ADS)
Ravindran, P.; Kjekshus, A.; Fjellvåg, H.; James, P.; Nordström, L.; Johansson, B.; Eriksson, O.
2001-04-01
The computational framework of this study is based on the local-spin-density approximation with first-principles full-potential linear muffin-tin orbital calculations including orbital polarization (OP) correction. We have studied the magnetic anisotropy for a series of bilayer CuAu(I)-type materials such as FeX, MnX (X=Ni,Pd,Pt), CoPt, NiPt, MnHg, and MnRh in a ferromagnetic state using experimental structural parameters to understand the microscopic origin of magnetic-anisotropy energy (MAE) in magnetic multilayers. Except for MnRh and MnHg, all these phases show perpendicular magnetization. We have analyzed our results in terms of angular momentum-, spin- and site-projected density of states, magnetic-angular-momentum-projected density of states, orbital-moment density of states, and total density of states. The orbital-moment number of states and the orbital-moment anisotropy for FeX (X=Ni,Pd,Pt) are calculated as a function of band filling to study its effect on MAE. The total and site-projected spin and orbital moments for all these systems are calculated with and without OP when the magnetization is along or perpendicular to the plane. The results are compared with available experimental as well as theoretical results. Our calculations show that OP always enhances the orbital moment in these phases and brings them closer to experimental values. The changes in MAE are analyzed in terms of exchange splitting, spin-orbit splitting, and tetragonal distortion/crystal-field splitting. The calculated MAE is found to be in good agreement with experimental values when the OP correction is included. Some of the materials considered here show large magnetic anisotropy of the order of meV. In particular we found that MnPt will have a very large MAE if it could be stabilized in a ferromagnetic configuration. Our analysis indicates that apart from large spin-orbit interaction and exchange interaction from at least one of the constituents, a large crystal-field splitting
Guelpa, Valérian; Laurent, Guillaume J; Sandoz, Patrick; Zea, July Galeano; Clévy, Cédric
2014-01-01
This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for Fourier-like phase calculations-leading to high resolution-while the period difference allows the removal of phase ambiguity and thus a high range-to-resolution ratio. The paper presents the measurement principle as well as the processing algorithms (source files are provided as supplementary materials). The theoretical and experimental performances are also discussed. The processing time is around 3 µs for a line of 780 pixels, which means that the measurement rate is mostly limited by the image acquisition frame rate. A 3-σ repeatability of 5 nm is experimentally demonstrated which has to be compared with the 168 µm measurement range. PMID:24625736
Fox, Stephen J; Pittock, Chris; Fox, Thomas; Tautermann, Christofer S; Malcolm, Noj; Skylaris, Chris-Kriton
2011-12-14
Biomolecular simulations with atomistic detail are often required to describe interactions with chemical accuracy for applications such as the calculation of free energies of binding or chemical reactions in enzymes. Force fields are typically used for this task but these rely on extensive parameterisation which in cases can lead to limited accuracy and transferability, for example for ligands with unusual functional groups. These limitations can be overcome with first principles calculations with methods such as density functional theory (DFT) but at a much higher computational cost. The use of electrostatic embedding can significantly reduce this cost by representing a portion of the simulated system in terms of highly localised charge distributions. These classical charge distributions are electrostatically coupled with the quantum system and represent the effect of the environment in which the quantum system is embedded. In this paper we describe and evaluate such an embedding scheme in which the polarisation of the electronic density by the embedding charges occurs self-consistently during the calculation of the density. We have implemented this scheme in a linear-scaling DFT program as our aim is to treat with DFT entire biomolecules (such as proteins) and large portions of the solvent. We test this approach in the calculation of interaction energies of ligands with biomolecules and solvent and investigate under what conditions these can be obtained with the same level of accuracy as when the entire system is described by DFT, for a variety of neutral and charged species. PMID:22168680
Haack, Jason; Papel, Ira D
2009-06-01
The nasal septum is a structure poorly understood and appreciated by the lay public and the nonotolaryngologist--head and neck surgeon alike. Deviation of the caudal portion of the nasal septum may result in nasal obstruction, a crooked nose, and columellar irregularities. The correction of a severely deviated caudal septum is one of the most difficult challenges of the otolaryngologist and facial plastic surgeon. A variety of options are available for correction of mild, to the most severe, deflections. This condition, as with all challenges in medicine, should not be a one size fits all or one surgery fits all situation. The skilled surgeon should understand the multiple options available for surgical correction and tailor fit the procedure to the deformity. PMID:19486740
NASA Astrophysics Data System (ADS)
Alam, Shadab; Ho, Shirley; Silvestri, Alessandra
2016-03-01
We use measurements from the Planck satellite mission and galaxy redshift surveys over the last decade to test three of the basic assumptions of the standard model of cosmology, ΛCDM (Λ cold dark matter): the spatial curvature of the universe, the nature of dark energy and the laws of gravity on large scales. We obtain improved constraints on several scenarios that violate one or more of these assumptions. We measure w0 = -0.94 ± 0.17 (18 per cent measurement) and 1 + wa = 1.16 ± 0.36 (31 per cent measurement) for models with a time-dependent equation of state, which is an improvement over current best constraints. In the context of modified gravity, we consider popular scalar-tensor models as well as a parametrization of the growth factor. In the case of one-parameter f(R) gravity models with a ΛCDM background, we constrain B0 < 1.36 × 10-5 (1σ C.L.), which is an improvement by a factor of 4 on the current best. We provide the very first constraint on the coupling parameters of general scalar-tensor theory and stringent constraint on the only free coupling parameter of Chameleon models. We also derive constraints on extended Chameleon models, improving the constraint on the coupling by a factor of 6 on the current best. The constraints on coupling parameter for Chameleon model rule out the value of β1 = 4/3 required for f(R) gravity. We also measure γ = 0.612 ± 0.072 (11.7 per cent measurement) for growth index parametrization. We improve all the current constraints by combining results from various galaxy redshift surveys in a coherent way, which includes a careful treatment of scale dependence introduced by modified gravity.
ERIC Educational Resources Information Center
Salemi, Michael K.
2009-01-01
One of the most important challenges facing college instructors of economics is helping students engage. Engagement is particularly important in a large-enrollment Principles of Economics course, where it can help students achieve a long-lived understanding of how economists use basic economic ideas to look at the world. The author reports how…
Gygi, F; Draeger, E W; de Supinski, B R; Yates, R K; Franchetti, F; Kral, S; Lorenz, J; Ueberhuber, C; Gunnels, J A; Sexton, J C
2005-04-25
We demonstrate that the Qbox code supports unprecedented large-scale First-Principles Molecular Dynamics (FPMD) applications on the BlueGene/L supercomputer. Qbox is an FPMD implementation specifically designed for large-scale parallel platforms such as BlueGene/L. Strong scaling tests for a Materials Science application show an 86% scaling efficiency between 1024 and 32,768 CPUs. Measurements of performance by means of hardware counters show that 37% of the peak FPU performance can be attained.
Power fluctuations, large deviations and turbulence
Bandi, Mahesh M; Chumakov, Sergei; Connaughton, Colm P
2008-01-01
We study local power fluctuations in numerical simulations of stationary, homogenous, isotropic turbulence in two and three dimensions with Gaussian forcing. Due to the near-Gaussianity of the one-point velocity distribution, the probability distribution function (pdf) of the local power is well modeled by the pdf of the product of two joint normally distributed variables. In appropriate units, this distribution is calculated exactly and shown to satisfy a Fluctuation Relation (FR) with a coefficient which depends on {epsilon}.
Bodnar, Richard J; Stellar, James R; Kraft, Tamar T; Loiacono, Ilyssa; Bajnath, Adesh; Rotella, Francis M; Barrientos, Alicia; Aghanori, Golshan; Olsson, Kerstin; Coke, Tricia; Huang, Donald; Luger, Zeke; Mousavi, Seyed Ali Reza; Dindyal, Trisha; Naqvi, Naveen; Kim, Jung-Yo
2013-01-01
In a large (250 registrants) general education lecture course, neuroscience principles were taught by two professors as co-instructors, starting with simple brain anatomy, chemistry, and function, proceeding to basic brain circuits of pleasure and pain, and progressing with fellow expert professors covering relevant philosophical, artistic, marketing, and anthropological issues. With this as a base, the course wove between fields of high relevance to psychology and neuroscience, such as food addiction and preferences, drug seeking and craving, analgesic pain-inhibitory systems activated by opiates and stress, neuroeconomics, unconscious decision-making, empathy, and modern neuroscientific techniques (functional magnetic resonance imaging and event-related potentials) presented by the co-instructors and other Psychology professors. With no formal assigned textbook, all lectures were PowerPoint-based, containing links to supplemental public-domain material. PowerPoints were available on Blackboard several days before the lecture. All lectures were also video-recorded and posted that evening. The course had a Facebook page for after-class conversation and one of the co-instructors communicated directly with students on Twitter in real time during lecture to provide momentary clarification and comment. In addition to graduate student Teaching Assistants (TAs), to allow for small group discussion, ten undergraduate students who performed well in a previous class were selected to serve as discussion leaders. The Discussion Leaders met four times at strategic points over the semester with groups of 20-25 current students, and received one credit of Independent Study, thus creating a course within a course. The course grade was based on weighted scores from two multiple-choice exams and a five-page writing assignment in which each student reviewed three unique, but brief original peer-review research articles (one page each) combined with expository writing on the first
Bodnar, Richard J.; Stellar, James R.; Kraft, Tamar T.; Loiacono, Ilyssa; Bajnath, Adesh; Rotella, Francis M.; Barrientos, Alicia; Aghanori, Golshan; Olsson, Kerstin; Coke, Tricia; Huang, Donald; Luger, Zeke; Mousavi, Seyed Ali Reza; Dindyal, Trisha; Naqvi, Naveen; Kim, Jung-Yo
2013-01-01
In a large (250 registrants) general education lecture course, neuroscience principles were taught by two professors as co-instructors, starting with simple brain anatomy, chemistry, and function, proceeding to basic brain circuits of pleasure and pain, and progressing with fellow expert professors covering relevant philosophical, artistic, marketing, and anthropological issues. With this as a base, the course wove between fields of high relevance to psychology and neuroscience, such as food addiction and preferences, drug seeking and craving, analgesic pain-inhibitory systems activated by opiates and stress, neuroeconomics, unconscious decision-making, empathy, and modern neuroscientific techniques (functional magnetic resonance imaging and event-related potentials) presented by the co-instructors and other Psychology professors. With no formal assigned textbook, all lectures were PowerPoint-based, containing links to supplemental public-domain material. PowerPoints were available on Blackboard several days before the lecture. All lectures were also video-recorded and posted that evening. The course had a Facebook page for after-class conversation and one of the co-instructors communicated directly with students on Twitter in real time during lecture to provide momentary clarification and comment. In addition to graduate student Teaching Assistants (TAs), to allow for small group discussion, ten undergraduate students who performed well in a previous class were selected to serve as discussion leaders. The Discussion Leaders met four times at strategic points over the semester with groups of 20–25 current students, and received one credit of Independent Study, thus creating a course within a course. The course grade was based on weighted scores from two multiple-choice exams and a five-page writing assignment in which each student reviewed three unique, but brief original peer-review research articles (one page each) combined with expository writing on the first
Gygi, F; Draeger, E; de Supinski, B; Yates, R K; Franchetti, F; Kral, S; Lorenz, J; Ueberhueber, C; Gunnels, J A; Sexton, J
2006-01-04
First-Principles Molecular Dynamics (FPMD) is an accurate, atomistic simulation approach that is routinely applied to a variety of areas including solid-state physics, chemistry, biochemistry and nanotechnology. FPMD enables one to perform predictive materials simulations, as no empirical or adjustable parameters are used to describe a given system. Instead, a quantum mechanical description of electrons is obtained by solving the Kohn-Sham equations within a pseudopotential plane-wave formalism. This rigorous first-principles treatment of electronic structure is computationally expensive and limits the size of tractable systems to a few hundred atoms on most currently available parallel computers. Developed specifically for large parallel systems at LLNL's Center for Applied Scientific Computing, the Qbox implementation of the FPMD method shows unprecedented performance and scaling on BlueGene/L.
Software engineering principles applied to large healthcare information systems--a case report.
Nardon, Fabiane Bizinella; de A Moura, Lincoln
2007-01-01
São Paulo is the largest city in Brazil and one of the largest cities in the world. In 2004, São Paulo City Department of Health decided to implement a Healthcare Information System to support managing healthcare services and provide an ambulatory health record. The resulting information system is one of the largest public healthcare information systems ever built, with more than 2 million lines of code. Although statistics shows that most software projects fail, and the risks for the São Paulo initiative were enormous, the information system was completed on-time and on-budget. In this paper, we discuss the software engineering principles adopted that allowed to accomplish that project's goals, hoping that sharing the experience of this project will help other healthcare information systems initiatives to succeed. PMID:17911673
Pecora, G; Kim, S; Celletti, R; Davarpanah, M
1995-01-01
Twenty patients with large endodontic lesions, which failed to respond to conventional endodontic therapy, were selected for this study. The lesions had a radiographic diameter of at least 10 mm, were removed by periradicular surgery, before retrofilling the apices with either super EBA or dessicated zinc oxide-eugenol. In 10 test sites large e-PTFE membranes (Gortex) were placed to cover the lesions, while at the control sites the lesions were not covered before resuturing. Radio-graphic analysis of the lesions at 3, 6, 9 and 12 months revealed that lesions covered with the membranes healed quicker than the control lesions, and that the quality and quantity of the regenerated bone was superior when membranes were used. Results of the study indicate that guided tissue regeneration (GTR) principles can be effectively applied to the healing of large periapical lesions, especially in through-and-through lesions. PMID:7642328
NASA Astrophysics Data System (ADS)
Tholander, C.; Tasnádi, F.; Abrikosov, I. A.; Hultman, L.; Birch, J.; Alling, B.
2015-11-01
The potential of quarternary wurtzite TMx /2Mx /2Al1 -xN (TM =Ti , Zr, Hf; M =Mg , Ca, Zn) alloys for piezoelectric applications is investigated using first-principles calculations. All considered alloys show increased piezoelectric response compared to pure AlN, and competing with the best ternary system proven to date: ScAlN. (Zr,Hf)x /2(Mg,Ca)x /2Al1 -xN alloys are particularly promising. Calculations reveal positive mixing enthalpies indicative for phase separating systems; their values are smaller compared to related nitride alloys, which still can be grown as metastable thin films. The wurtzite phase of the alloys is lowest in energy at least up to x =0.5 and for Tix /2Znx /2Al1 -xN in the full composition range. Moreover, calculations reveal that wurtzite TM0.5Zn0.5N (TM =Ti , Zr, Hf) are piezoelectric alloys with d33 ,f=19.95 , 29.89, and 24.65 pC/N respectively, up to six times that of AlN. Finally, we discuss the physical origin behind the increased piezoelectric response and show that the energy difference between tetrahedrally coordinated zinc-blende (B3) and the layered hexagonal (Bk) phases of the TM0.5M0.5N alloy can be used as a descriptor in a high-throughput search for complex wurtzite alloys with high piezoelectric response.
BrainModes: a principled approach to modeling and measuring large-scale neuronal activity.
Breakspear, Michael J; Daffertshofer, Andreas; Ritter, Petra
2009-09-30
Complex systems, such as the brain, exhibit multiple levels of organization due to processes which support the separation of scales across time and/or space. That is, cooperative phenomena--or "modes" of activity--occurring at one scale give rise to coherent spatiotemporal structures at a coarser scale. In turn, structures at the coarser scale constrain--and hence influence--emerging activity at a finer scale. BrainModes is an annual scientific summit which seeks to bring together experimental, computational and theoretical neuroscientists engaged at different levels of organization, with the goal of advancing a principled approach to understanding brain function based on the concept of cooperative phenomena in complex systems. Phenomena of particular interest include synchronization, stochastic influences, and spatiotemporal processes in both healthy and pathological states such as seizures. This Special Issue reports the 2008 BrainModes Workshop, held in Amsterdam (December 2008) which focused on the application of this framework to the analysis of brain oscillations and synchronization phenomena across time scales. PMID:19607859
Nurbawono, Argo; Liu, Shuanglong; Zhang, Chun
2015-04-21
Time dependent density functional tight binding (TDDFTB) method is implemented with sparse matrix techniques and improved parallelization algorithms. The method is employed to calculate the optical properties of various Si nanocrystals (NCs). The calculated light absorption spectra of small Si NCs from TDDFTB were found to be comparable with many body perturbation methods utilizing planewave basis sets. For large Si NCs (more than a thousand atoms) that are beyond the reach of conventional approaches, the TDDFTB method is able to produce reasonable results that are consistent with prior experiments. We also employed the method to study the effects of surface chemistry on the optical properties of large Si NCs. We learned that the optical properties of Si NCs can be manipulated with small molecule passivations such as methyl, hydroxyl, amino, and fluorine. In general, the shifts and profiles in the absorption spectra can be tuned with suitably chosen passivants.
Large-Scale Computations Leading to a First-Principles Approach to Nuclear Structure
Ormand, W E; Navratil, P
2003-08-18
We report on large-scale applications of the ab initio, no-core shell model with the primary goal of achieving an accurate description of nuclear structure from the fundamental inter-nucleon interactions. In particular, we show that realistic two-nucleon interactions are inadequate to describe the low-lying structure of {sup 10}B, and that realistic three-nucleon interactions are essential.
A first principle particle mesh method for solution SAXS of large bio-molecular systems
NASA Astrophysics Data System (ADS)
Marchi, Massimo
2016-07-01
This paper will show that the solution small angle X-ray scattering (SAXS) intensity of globular and membrane proteins can be efficiently and accurately computed from molecular dynamics trajectories using 3D fast Fourier transforms (FFTs). A suitable particle meshing interpolation, similar to the one used in smooth particle mesh Ewald for electrostatic energies and forces, was combined with a uniform solvent density FFT padding scheme to obtain a convenient SAXS spectral resolution. The CPU time scaling of the method, as a function of system size, is highly favorable and its application to large systems such as solutions of solvated membrane proteins is computationally undemanding. Differently from other approaches, all contributions from the simulation cell are included. This means that the subtraction of the buffer from the solution scattering intensity is straightforward and devoid of artifact due to ad hoc definitions of proximal and distal solvent intensity contributions.
A first principle particle mesh method for solution SAXS of large bio-molecular systems.
Marchi, Massimo
2016-07-28
This paper will show that the solution small angle X-ray scattering (SAXS) intensity of globular and membrane proteins can be efficiently and accurately computed from molecular dynamics trajectories using 3D fast Fourier transforms (FFTs). A suitable particle meshing interpolation, similar to the one used in smooth particle mesh Ewald for electrostatic energies and forces, was combined with a uniform solvent density FFT padding scheme to obtain a convenient SAXS spectral resolution. The CPU time scaling of the method, as a function of system size, is highly favorable and its application to large systems such as solutions of solvated membrane proteins is computationally undemanding. Differently from other approaches, all contributions from the simulation cell are included. This means that the subtraction of the buffer from the solution scattering intensity is straightforward and devoid of artifact due to ad hoc definitions of proximal and distal solvent intensity contributions. PMID:27475396
The PubChemQC project: A large chemical database from the first principle calculations
NASA Astrophysics Data System (ADS)
Maho, Nakata
2015-12-01
In this research, we have been constructing a large database of molecules by ab initio calculations. Currently, we have over 1.53 million entries of 6-31G* B3LYP optimized geometries and ten excited states by 6-31+G* TDDFT calculations. To calculate molecules, we only refer the InChI (International Chemical Identifier) representation of chemical formula by the International Union of Pure and Applied Chemistry (IUPAC), thus, no reference to experimental data. These results are open to public at http://pubchemqc.riken.jp/. The molecular data have been taken from the PubChem Project (http://pubchem.ncbi.nlm.nih.gov/) which is one of the largest in the world (approximately 63 million molecules are listed) and free (public domain) database. Our final goal is, using these data, to develop a molecular search engine or molecular expert system to find molecules which have desired properties.
First principles study of lattice thermal conductivity and large isotope effect in materials
NASA Astrophysics Data System (ADS)
Broido, David; Lindsay, Lucas; Reinecke, Tom
2014-03-01
The isotope effect--the percent enhancement to a material's lattice thermal conductivity, k, with isotopic purification--depends on the interplay between phonon-isotope and phonon-phonon scattering. Diamond is known to have the largest measured room temperature (RT) isotope effect of any bulk crystal, achieving a k enhancement of 50%. Using an ab initioBoltzmann transport equation approach, we have identified several other materials with far larger RT isotope effects. In particular, we find that germanium carbide (GeC) and beryllium selenide (BeSe) have RT isotope effects of 450%, almost an order of magnitude higher than that in diamond. Isotopic purification in these materials gives surprisingly high intrinsic RT k values, over 1500 Wm-1K-1 for GeC and over 600 Wm-1 K-1 for BeSe, well above those of the best metals. These large values stem from fundamental material properties that give both enhanced phonon scattering by isotopes and weak anharmonic phonon-phonon scattering. The physical insights discussed in this work provide guidance for efficient manipulation of thermal transport properties of compound semiconductors through isotopic modification. This work was supported by ONR, DARPA and NSF.
Computer generation of random deviates.
Cormack, J; Shuter, B
1991-06-01
The need for random deviates arises in many scientific applications, such as the simulation of physical processes, numerical evaluation of complex mathematical formulae and the modeling of decision processes. In medical physics, Monte Carlo simulations have been used in radiology, radiation therapy and nuclear medicine. Specific instances include the modelling of x-ray scattering processes and the addition of random noise to images or curves in order to assess the effects of various processing procedures. Reliable sources of random deviates with statistical properties indistinguishable from true random deviates are a fundamental necessity for such tasks. This paper provides a review of computer algorithms which can be used to generate uniform random deviates and other distributions of interest to medical physicists, along with a few caveats relating to various problems and pitfalls which can occur. Source code listings for the generators discussed (in FORTRAN, Turbo-PASCAL and Data General ASSEMBLER) are available on request from the authors. PMID:1747086
NASA Astrophysics Data System (ADS)
Reeves, Kyle; Yao, Yi; Kanai, Yosuke
Electronic stopping describes the transfer of energy from a highly-energetic charged particle to electrons in a material. This process induces massive electronic excitations via interaction between the material and the highly localized electric field from the charged particle. Understanding this phenomenon in condensed matter systems under proton irradiation has implications in various modern technologies. First-principles simulations, based on our recently-developed large-scale real-time time-dependent density functional theory approach, provide a detailed description of how electrons are excited via a non-equilibrium energy transfer from protons on the attosecond time scale. We apply this computational approach to the important case of liquid water under proton irradiation. Our work reveals several key features of the excitation dynamics at the mesoscopic and molecular levels which support a clearer understanding of the water radiolysis mechanism under proton irradiation. Importantly, we will demonstrate a first-principles determination of the energy transfer rate, (i.e. electronic stopping power) in liquid water, and a comparison to existing empirical models will be presented. We will conclude by discussing how the exchange-correlation approximation influences the calculation of the electronic stopping power.
NASA Astrophysics Data System (ADS)
Ono, Tomoya; Tsukamoto, Shigeru
2016-01-01
We present a fast and stable numerical technique to obtain the self-energy terms of electrodes for first-principles electron transport calculations. Although first-principles calculations based on the real-space finite-difference method are advantageous for execution on massively parallel computers, large-scale transport calculations are hampered by the computational cost and numerical instability of the computation of the self-energy terms. Using the orthogonal complement vectors of the space spanned by the generalized Bloch waves that actually contribute to transport phenomena, the computational accuracy of transport properties is significantly improved with a moderate computational cost. To demonstrate the efficiency of the present technique, the electron transport properties of a Stone-Wales (SW) defect in graphene and silicene are examined. The resonance scattering of the SW defect is observed in the conductance spectrum of silicene since the σ* state of silicene lies near the Fermi energy. In addition, we found that one conduction channel is sensitive to a defect near the Fermi energy, while the other channel is hardly affected. This characteristic behavior of the conduction channels is interpreted in terms of the bonding network between the bilattices of the honeycomb structure in the formation of the SW defect. The present technique enables us to distinguish the different behaviors of the two conduction channels in graphene and silicene owing to its excellent accuracy.
Schubert, Walter
2013-01-01
Understanding biological systems at the level of their relational (emergent) molecular properties in functional protein networks relies on imaging methods, able to spatially resolve a tissue or a cell as a giant, non-random, topologically defined collection of interacting supermolecules executing myriads of subcellular mechanisms. Here, the development and findings of parameter-unlimited functional super-resolution microscopy are described—a technology based on the fluorescence imaging cycler (IC) principle capable of co-mapping thousands of distinct biomolecular assemblies at high spatial resolution and differentiation (<40 nm distances). It is shown that the subcellular and transcellular features of such supermolecules can be described at the compositional and constitutional levels; that the spatial connection, relational stoichiometry, and topology of supermolecules generate hitherto unrecognized functional self-segmentation of biological tissues; that hierarchical features, common to thousands of simultaneously imaged supermolecules, can be identified; and how the resulting supramolecular order relates to spatial coding of cellular functionalities in biological systems. A large body of observations with IC molecular systems microscopy collected over 20 years have disclosed principles governed by a law of supramolecular segregation of cellular functionalities. This pervades phenomena, such as exceptional orderliness, functional selectivity, combinatorial and spatial periodicity, and hierarchical organization of large molecular systems, across all species investigated so far. This insight is based on the high degree of specificity, selectivity, and sensitivity of molecular recognition processes for fluorescence imaging beyond the spectral resolution limit, using probe libraries controlled by ICs. © 2013 The Authors. Journal of Molecular Recognition published by John Wiley & Sons, Ltd. PMID:24375580
48 CFR 2001.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... REGULATORY COMMISSION ACQUISITION REGULATION SYSTEM Deviations From the FAR and the NRCAR 2001.404 Class deviations. Class deviations affect more than one contracting action. Where deviations from the FAR or...
Standard Deviation for Small Samples
ERIC Educational Resources Information Center
Joarder, Anwar H.; Latif, Raja M.
2006-01-01
Neater representations for variance are given for small sample sizes, especially for 3 and 4. With these representations, variance can be calculated without a calculator if sample sizes are small and observations are integers, and an upper bound for the standard deviation is immediate. Accessible proofs of lower and upper bounds are presented for…
NASA Astrophysics Data System (ADS)
Guo, Peng-Jie; Yang, Huan-Cheng; Zhang, Bing-Jing; Liu, Kai; Lu, Zhong-Yi
2016-06-01
By the first-principles electronic structure calculations, we have systematically studied the electronic structures of recently discovered extremely large magnetoresistance (XMR) materials LaSb and LaBi. We find that both LaSb and LaBi are semimetals with the electron and hole carriers in balance. The calculated carrier densities on the order of 1020cm-3 are in good agreement with the experimental values, implying long mean-free time of carriers at low temperatures and thus high carrier mobilities. With a semiclassical two-band model, the charge compensation and high carrier mobilities naturally explain: (i) the XMR observed in LaSb and LaBi, (ii) the nonsaturating quadratic dependence of XMR on an external magnetic field, and (iii) the resistivity plateau in the turn-on temperature behavior at very low temperatures. The explanation of these features without resorting to the topological effect indicates that they should be the common characteristics of all electron-hole compensated semimetals.
Han, Yong; Evans, James W.
2015-10-27
Large-scale first-principles density functional theory calculations are performed to investigate the adsorption and diffusion of Ru adatoms on monolayer graphene (G) supported on Ru(0001). The G sheet exhibits a periodic moiré-cell superstructure due to lattice mismatch. Within a moiré cell, there are three distinct regions: fcc, hcp, and mound, in which the C6-ring center is above a fcc site, a hcp site, and a surface Ru atom of Ru(0001), respectively. The adsorption energy of a Ru adatom is evaluated at specific sites in these distinct regions. We find the strongest binding at an adsorption site above a C atom inmore » the fcc region, next strongest in the hcp region, then the fcc-hcp boundary (ridge) between these regions, and the weakest binding in the mound region. Behavior is similar to that observed from small-unit-cell calculations of Habenicht et al. [Top. Catal. 57, 69 (2014)], which differ from previous large-scale calculations. We determine the minimum-energy path for local diffusion near the center of the fcc region and obtain a local diffusion barrier of ~0.48 eV. We also estimate a significantly lower local diffusion barrier in the ridge region. These barriers and information on the adsorption energy variation facilitate development of a realistic model for the global potential energy surface for Ru adatoms. Furthermore, this in turn enables simulation studies elucidating diffusion-mediated directed-assembly of Ru nanoclusters during deposition of Ru on G/Ru(0001).« less
Han, Yong; Evans, James W.
2015-10-27
Large-scale first-principles density functional theory calculations are performed to investigate the adsorption and diffusion of Ru adatoms on monolayer graphene (G) supported on Ru(0001). The G sheet exhibits a periodic moiré-cell superstructure due to lattice mismatch. Within a moiré cell, there are three distinct regions: fcc, hcp, and mound, in which the C6-ring center is above a fcc site, a hcp site, and a surface Ru atom of Ru(0001), respectively. The adsorption energy of a Ru adatom is evaluated at specific sites in these distinct regions. We find the strongest binding at an adsorption site above a C atom in the fcc region, next strongest in the hcp region, then the fcc-hcp boundary (ridge) between these regions, and the weakest binding in the mound region. Behavior is similar to that observed from small-unit-cell calculations of Habenicht et al. [Top. Catal. 57, 69 (2014)], which differ from previous large-scale calculations. We determine the minimum-energy path for local diffusion near the center of the fcc region and obtain a local diffusion barrier of ~0.48 eV. We also estimate a significantly lower local diffusion barrier in the ridge region. These barriers and information on the adsorption energy variation facilitate development of a realistic model for the global potential energy surface for Ru adatoms. Furthermore, this in turn enables simulation studies elucidating diffusion-mediated directed-assembly of Ru nanoclusters during deposition of Ru on G/Ru(0001).
Han, Yong; Evans, James W.
2015-10-28
Large-scale first-principles density functional theory calculations are performed to investigate the adsorption and diffusion of Ru adatoms on monolayer graphene (G) supported on Ru(0001). The G sheet exhibits a periodic moiré-cell superstructure due to lattice mismatch. Within a moiré cell, there are three distinct regions: fcc, hcp, and mound, in which the C{sub 6}-ring center is above a fcc site, a hcp site, and a surface Ru atom of Ru(0001), respectively. The adsorption energy of a Ru adatom is evaluated at specific sites in these distinct regions. We find the strongest binding at an adsorption site above a C atom in the fcc region, next strongest in the hcp region, then the fcc-hcp boundary (ridge) between these regions, and the weakest binding in the mound region. Behavior is similar to that observed from small-unit-cell calculations of Habenicht et al. [Top. Catal. 57, 69 (2014)], which differ from previous large-scale calculations. We determine the minimum-energy path for local diffusion near the center of the fcc region and obtain a local diffusion barrier of ∼0.48 eV. We also estimate a significantly lower local diffusion barrier in the ridge region. These barriers and information on the adsorption energy variation facilitate development of a realistic model for the global potential energy surface for Ru adatoms. This in turn enables simulation studies elucidating diffusion-mediated directed-assembly of Ru nanoclusters during deposition of Ru on G/Ru(0001)
Perception of aircraft Deviation Cues
NASA Technical Reports Server (NTRS)
Martin, Lynne; Azuma, Ronald; Fox, Jason; Verma, Savita; Lozito, Sandra
2005-01-01
To begin to address the need for new displays, required by a future airspace concept to support new roles that will be assigned to flight crews, a study of potentially informative display cues was undertaken. Two cues were tested on a simple plan display - aircraft trajectory and flight corridor. Of particular interest was the speed and accuracy with which participants could detect an aircraft deviating outside its flight corridor. Presence of the trajectory cue significantly reduced participant reaction time to a deviation while the flight corridor cue did not. Although non-significant, the flight corridor cue seemed to have a relationship with the accuracy of participants judgments rather than their speed. As this is the second of a series of studies, these issues will be addressed further in future studies.
48 CFR 1301.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... DEPARTMENT OF COMMERCE ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 1301.403 Individual deviations. The designee authorized to approve individual deviations from the FAR is set forth in CAM 1301.70....
48 CFR 1401.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... DEPARTMENT OF THE INTERIOR ACQUISITION REGULATION SYSTEM Deviations from the FAR and DIAR 1401.403 Individual deviations. (a) The Director, PAM, is authorized to approve deviations of FAR provisions (see FAR 1.4)...
48 CFR 2001.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... NUCLEAR REGULATORY COMMISSION ACQUISITION REGULATION SYSTEM Deviations From the FAR and the NRCAR 2001.403 Individual deviations. In individual cases, deviations from either the FAR or the NRCAR will be...
48 CFR 301.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... ACQUISITION REGULATION SYSTEM Deviations From the FAR 301.403 Individual deviations. Contracting activities shall prepare requests for individual deviations to either the FAR or HHSAR in accordance with 301.470....
48 CFR 2801.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... JUSTICE ACQUISITION REGULATIONS SYSTEM Deviations From the FAR and JAR 2801.404 Class deviations. Requests for class deviations from the FAR or the JAR shall be submitted to the PE. The PE will consult...
48 CFR 401.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... ACQUISITION REGULATION SYSTEM Deviations From the FAR and AGAR 401.404 Class deviations. Where deviations from the FAR or AGAR are considered necessary for classes of contracts, requests for authority to...
48 CFR 401.404 - Class deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... ACQUISITION REGULATION SYSTEM Deviations From the FAR and AGAR 401.404 Class deviations. Where deviations from the FAR or AGAR are considered necessary for classes of contracts, requests for authority to...
van Vliet, Danique; Bruinenberg, Vibeke M.; Mazzola, Priscila N.; van Faassen, Martijn H. J. R.; de Blaauw, Pim; Kema, Ido P.; Heiner-Fokkema, M. Rebecca; van Anholt, Rogier D.; van der Zee, Eddy A.; van Spronsen, Francjan J.
2015-01-01
Background Phenylketonuria (PKU) was the first disorder in which severe neurocognitive dysfunction could be prevented by dietary treatment. However, despite this effect, neuropsychological outcome in PKU still remains suboptimal and the phenylalanine-restricted diet is very demanding. To improve neuropsychological outcome and relieve the dietary restrictions for PKU patients, supplementation of large neutral amino acids (LNAA) is suggested as alternative treatment strategy that might correct all brain biochemical disturbances caused by high blood phenylalanine, and thereby improve neurocognitive functioning. Objective As a proof-of-principle, this study aimed to investigate all hypothesized biochemical treatment objectives of LNAA supplementation (normalizing brain phenylalanine, non-phenylalanine LNAA, and monoaminergic neurotransmitter concentrations) in PKU mice. Methods C57Bl/6 Pah-enu2 (PKU) mice and wild-type mice received a LNAA supplemented diet, an isonitrogenic/isocaloric high-protein control diet, or normal chow. After six weeks of dietary treatment, blood and brain amino acid and monoaminergic neurotransmitter concentrations were assessed. Results In PKU mice, the investigated LNAA supplementation regimen significantly reduced blood and brain phenylalanine concentrations by 33% and 26%, respectively, compared to normal chow (p<0.01), while alleviating brain deficiencies of some but not all supplemented LNAA. Moreover, LNAA supplementation in PKU mice significantly increased brain serotonin and norepinephrine concentrations from 35% to 71% and from 57% to 86% of wild-type concentrations (p<0.01), respectively, but not brain dopamine concentrations (p = 0.307). Conclusions This study shows that LNAA supplementation without dietary phenylalanine restriction in PKU mice improves brain biochemistry through all three hypothesized biochemical mechanisms. Thereby, these data provide proof-of-concept for LNAA supplementation as a valuable alternative dietary
48 CFR 1401.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... THE INTERIOR ACQUISITION REGULATION SYSTEM Deviations from the FAR and DIAR 1401.404 Class deviations. (a) The Director, PAM, is authorized to approve class deviations of FAR or DIAR provisions which... actions which will be affected. (c) For a FAR class deviation the Director, PAM, shall consult with...
48 CFR 1.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... ACQUISITION REGULATIONS SYSTEM Deviations from the FAR 1.404 Class deviations. Class deviations affect more... basis, it should propose a FAR revision, if appropriate. Civilian agencies, other than NASA, must furnish a copy of each approved class deviation to the FAR Secretariat. (a) For civilian agencies...
48 CFR 801.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... OF VETERANS AFFAIRS ACQUISITION REGULATION SYSTEM Deviations from the FAR or VAAR 801.404 Class deviations. Authority to authorize class deviations from the FAR and VAAR is delegated to the SPE and is further delegated to the DSPE. The DSPE may authorize class deviations from the FAR and VAAR when a...
48 CFR 801.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... DEPARTMENT OF VETERANS AFFAIRS ACQUISITION REGULATION SYSTEM Deviations from the FAR or VAAR 801.403 Individual deviations. (a) Authority to authorize individual deviations from the FAR and VAAR is delegated to... deviate from the policies in the FAR or VAAR, the contracting officer, in accordance with...
14 CFR 125.3 - Deviation authority.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Deviation authority. 125.3 Section 125.3... OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT General § 125.3 Deviation authority. (a... justification for the deviation requested. (d) After February 2, 2012, no deviation authority from the...
14 CFR 125.3 - Deviation authority.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Deviation authority. 125.3 Section 125.3... OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT General § 125.3 Deviation authority. (a... justification for the deviation requested. (d) After February 2, 2012, no deviation authority from the...
14 CFR 125.3 - Deviation authority.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Deviation authority. 125.3 Section 125.3... OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT General § 125.3 Deviation authority. (a... justification for the deviation requested. (d) After February 2, 2012, no deviation authority from the...
48 CFR 2501.404 - Class deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Class deviations. 2501.404 Section 2501.404 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.404 Class deviations. Class deviations may...
Code of Federal Regulations, 2014 CFR
2014-01-01
... proposed deviation from this part would be a deviation from 10 CFR part 600, the deviation must also be... 10 Energy 4 2014-01-01 2014-01-01 false Deviations. 602.4 Section 602.4 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS EPIDEMIOLOGY AND OTHER HEALTH STUDIES FINANCIAL...
Code of Federal Regulations, 2013 CFR
2013-01-01
... proposed deviation from this part would be a deviation from 10 CFR part 600, the deviation must also be... 10 Energy 4 2013-01-01 2013-01-01 false Deviations. 602.4 Section 602.4 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS EPIDEMIOLOGY AND OTHER HEALTH STUDIES FINANCIAL...
Code of Federal Regulations, 2010 CFR
2010-01-01
... proposed deviation from this part would be a deviation from 10 CFR part 600, the deviation must also be... 10 Energy 4 2010-01-01 2010-01-01 false Deviations. 602.4 Section 602.4 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS EPIDEMIOLOGY AND OTHER HEALTH STUDIES FINANCIAL...
Code of Federal Regulations, 2012 CFR
2012-01-01
... proposed deviation from this part would be a deviation from 10 CFR part 600, the deviation must also be... 10 Energy 4 2012-01-01 2012-01-01 false Deviations. 602.4 Section 602.4 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS EPIDEMIOLOGY AND OTHER HEALTH STUDIES FINANCIAL...
Code of Federal Regulations, 2011 CFR
2011-01-01
... proposed deviation from this part would be a deviation from 10 CFR part 600, the deviation must also be... 10 Energy 4 2011-01-01 2011-01-01 false Deviations. 602.4 Section 602.4 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS EPIDEMIOLOGY AND OTHER HEALTH STUDIES FINANCIAL...
48 CFR 401.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... AGRICULTURE ACQUISITION REGULATION SYSTEM Deviations From the FAR and AGAR 401.403 Individual deviations. In individual cases, deviations from either the FAR or the AGAR will be authorized only when essential to effect... AGAR, after coordinating with the General Counsel and the SPE. No deviations from the FAR or AGAR...
48 CFR 401.403 - Individual deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... AGRICULTURE ACQUISITION REGULATION SYSTEM Deviations From the FAR and AGAR 401.403 Individual deviations. In individual cases, deviations from either the FAR or the AGAR will be authorized only when essential to effect... AGAR, after coordinating with the General Counsel and the SPE. No deviations from the FAR or AGAR...
48 CFR 2501.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Class deviations. 2501.404 Section 2501.404 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.404 Class deviations. Class deviations may...
48 CFR 2501.404 - Class deviations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Class deviations. 2501.404 Section 2501.404 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.404 Class deviations. Class deviations may...
48 CFR 2501.404 - Class deviations.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Class deviations. 2501.404 Section 2501.404 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.404 Class deviations. Class deviations may...
48 CFR 1501.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Individual deviations. 1501.403 Section 1501.403 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL GENERAL Deviations 1501.403 Individual deviations. Requests for individual deviations from the FAR and the EPAAR shall be submitted to the Head...
48 CFR 1501.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Class deviations. 1501.404 Section 1501.404 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL GENERAL Deviations 1501.404 Class deviations. Requests for class deviations to the FAR and the EPAAR shall be submitted to the HCA for processing...
48 CFR 1501.404 - Class deviations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Class deviations. 1501.404 Section 1501.404 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL GENERAL Deviations 1501.404 Class deviations. Requests for class deviations to the FAR and the EPAAR shall be submitted to the HCA for processing...
48 CFR 1501.403 - Individual deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Individual deviations. 1501.403 Section 1501.403 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL GENERAL Deviations 1501.403 Individual deviations. Requests for individual deviations from the FAR and the EPAAR shall be submitted to the Head...
48 CFR 1501.403 - Individual deviations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Individual deviations. 1501.403 Section 1501.403 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL GENERAL Deviations 1501.403 Individual deviations. Requests for individual deviations from the FAR and the EPAAR shall be submitted to the Head...
48 CFR 1501.404 - Class deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Class deviations. 1501.404 Section 1501.404 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY GENERAL GENERAL Deviations 1501.404 Class deviations. Requests for class deviations to the FAR and the EPAAR shall be submitted to the HCA for processing...
Assessment and classification of protocol deviations
Ghooi, Ravindra Bhaskar; Bhosale, Neelambari; Wadhwani, Reena; Divate, Pathik; Divate, Uma
2016-01-01
Introduction: Deviations from the approved trial protocol are common during clinical trials. They have been conventionally classified as deviations or violations, depending on their impact on the trial. Methods: A new method has been proposed by which deviations are classified in five grades from 1 to 5. A deviation of Grade 1 has no impact on the subjects’ well-being or on the quality of data. At the maximum, a deviation Grade 5 leads to the death of the subject. This method of classification was applied to deviations noted in the center over the last 3 years. Results: It was observed that most deviations were of Grades 1 and 2, with fewer falling in Grades 3 and 4. There were no deviations that led to the death of the subject (Grade 5). Discussion: This method of classification would help trial managers decide on the action to be taken on the occurrence of deviations, which would be based on their impact. PMID:27453830
Allan deviation analysis of financial return series
NASA Astrophysics Data System (ADS)
Hernández-Pérez, R.
2012-05-01
We perform a scaling analysis for the return series of different financial assets applying the Allan deviation (ADEV), which is used in the time and frequency metrology to characterize quantitatively the stability of frequency standards since it has demonstrated to be a robust quantity to analyze fluctuations of non-stationary time series for different observation intervals. The data used are opening price daily series for assets from different markets during a time span of around ten years. We found that the ADEV results for the return series at short scales resemble those expected for an uncorrelated series, consistent with the efficient market hypothesis. On the other hand, the ADEV results for absolute return series for short scales (first one or two decades) decrease following approximately a scaling relation up to a point that is different for almost each asset, after which the ADEV deviates from scaling, which suggests that the presence of clustering, long-range dependence and non-stationarity signatures in the series drive the results for large observation intervals.
NASA Astrophysics Data System (ADS)
Zonias, Nicholas; Lagoudakis, Pavlos; Skylaris, Chris-Kriton
2010-01-01
We present a computational study by density functional theory (DFT) of entire silicon nanorods with up to 1648 atoms without any periodicity or symmetry imposed. The nanorods have been selected to have varying aspect ratios and levels of surface passivation with hydrogen. The structures of the nanorods have been optimized using a density functional tight-binding approach, while energies and electronic properties have been computed using linear-scaling DFT with plane-wave accuracy with the ONETEP (Skylaris et al 2005 J. Chem. Phys. 122 084119) program. The aspect ratio and surface passivation (1 × 1 and 2 × 1 reconstructions) along with the size of the nanorods which leads to quantum confinement along all three dimensions, significantly affect their electronic properties. The structures of the nanorods also show interesting behaviour as, depending on their characteristics, they can in certain areas retain the structure of bulk silicon while in other parts significantly deviate from it.
48 CFR 501.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... GENERAL SERVICES ADMINISTRATION ACQUISITION REGULATION SYSTEM Deviations From the FAR and GSAR 501.403... Contracting Activity (HCA) must approve an individual deviation to the FAR. The authority to grant...
Code of Federal Regulations, 2014 CFR
2014-01-01
... life or property, the certificate holder may deviate from any requirement of subpart D of this part, or..., notify the Regional Airports Division Manager of the nature, extent, and duration of the deviation....
48 CFR 1.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Individual deviations. 1.403 Section 1.403 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations from the FAR 1.403 Individual deviations....
48 CFR 501.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... SERVICES ADMINISTRATION ACQUISITION REGULATION SYSTEM Deviations From the FAR and GSAR 501.404 Class... an individual contract action. (1) A class deviation to the FAR must be forwarded by the cognizant HCA to GSA's SPE for approval. Prior to approving a class deviation to the FAR, the SPE will...
48 CFR 1201.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... ACQUISITION REGULATIONS SYSTEM 70-Deviations From the FAR and TAR 1201.404 Class deviations. The SPE may grant in writing class deviations from the (FAR) 48 CFR chapter 1 and (TAR) 48 CFR chapter 12, unless (FAR) 48 CFR 1.405(e) applies....
48 CFR 1901.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... THE BROADCASTING BOARD OF GOVERNORS ACQUISITION REGULATION SYSTEM Deviations From the FAR 1901.403 Individual deviations. Deviations from the IAAR or the FAR in individual cases shall be authorized by the Board Procurement Executive or a designee unless FAR 1.405(e) is applicable. The request shall cite...
Code of Federal Regulations, 2013 CFR
2013-01-01
... 10 Energy 4 2013-01-01 2013-01-01 false Deviations. 961.4 Section 961.4 Energy DEPARTMENT OF ENERGY STANDARD CONTRACT FOR DISPOSAL OF SPENT NUCLEAR FUEL AND/OR HIGH-LEVEL RADIOACTIVE WASTE General § 961.4 Deviations. Requests for authority to deviate from this part shall be submitted in writing...
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 4 2012-01-01 2012-01-01 false Deviations. 961.4 Section 961.4 Energy DEPARTMENT OF ENERGY STANDARD CONTRACT FOR DISPOSAL OF SPENT NUCLEAR FUEL AND/OR HIGH-LEVEL RADIOACTIVE WASTE General § 961.4 Deviations. Requests for authority to deviate from this part shall be submitted in writing...
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Deviations. 961.4 Section 961.4 Energy DEPARTMENT OF ENERGY STANDARD CONTRACT FOR DISPOSAL OF SPENT NUCLEAR FUEL AND/OR HIGH-LEVEL RADIOACTIVE WASTE General § 961.4 Deviations. Requests for authority to deviate from this part shall be submitted in writing...
48 CFR 301.403 - Individual deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Individual deviations. 301.403 Section 301.403 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL HHS ACQUISITION REGULATION SYSTEM Deviations From the FAR 301.403 Individual deviations. Contracting...
48 CFR 301.404 - Class deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Class deviations. 301.404 Section 301.404 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL HHS ACQUISITION REGULATION SYSTEM Deviations From the FAR 301.404 Class deviations. Contracting activities shall...
48 CFR 301.403 - Individual deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Individual deviations. 301.403 Section 301.403 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL HHS ACQUISITION REGULATION SYSTEM Deviations From the FAR 301.403 Individual deviations. Contracting...
48 CFR 301.404 - Class deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Class deviations. 301.404 Section 301.404 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL HHS ACQUISITION REGULATION SYSTEM Deviations From the FAR 301.404 Class deviations. Contracting activities shall...
Introducing the Mean Absolute Deviation "Effect" Size
ERIC Educational Resources Information Center
Gorard, Stephen
2015-01-01
This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme…
48 CFR 2501.403 - Individual deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Individual deviations. 2501.403 Section 2501.403 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.403 Individual deviations....
Code of Federal Regulations, 2011 CFR
2011-01-01
... the deviation and nuclear power reactor(s) affected; (e) A statement as to whether the deviation has... 10 Energy 4 2011-01-01 2011-01-01 false Deviations. 961.4 Section 961.4 Energy DEPARTMENT OF ENERGY STANDARD CONTRACT FOR DISPOSAL OF SPENT NUCLEAR FUEL AND/OR HIGH-LEVEL RADIOACTIVE WASTE...
48 CFR 2501.403 - Individual deviations.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Individual deviations. 2501.403 Section 2501.403 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.403 Individual deviations....
48 CFR 2501.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Individual deviations. 2501.403 Section 2501.403 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.403 Individual deviations....
48 CFR 2501.403 - Individual deviations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Individual deviations. 2501.403 Section 2501.403 Federal Acquisition Regulations System NATIONAL SCIENCE FOUNDATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Deviations From the FAR 2501.403 Individual deviations....
The Standard Deviation of Launch Vehicle Environments
NASA Technical Reports Server (NTRS)
Yunis, Isam
2005-01-01
Statistical analysis is used in the development of the launch vehicle environments of acoustics, vibrations, and shock. The standard deviation of these environments is critical to accurate statistical extrema. However, often very little data exists to define the standard deviation and it is better to use a typical standard deviation than one derived from a few measurements. This paper uses Space Shuttle and expendable launch vehicle flight data to define a typical standard deviation for acoustics and vibrations. The results suggest that 3dB is a conservative and reasonable standard deviation for the source environment and the payload environment.
Structure of deviations from optimality in biological systems
Pérez-Escudero, Alfonso; Rivera-Alba, Marta; de Polavieja, Gonzalo G.
2009-01-01
Optimization theory has been used to analyze evolutionary adaptation. This theory has explained many features of biological systems, from the genetic code to animal behavior. However, these systems show important deviations from optimality. Typically, these deviations are large in some particular components of the system, whereas others seem to be almost optimal. Deviations from optimality may be due to many factors in evolution, including stochastic effects and finite time, that may not allow the system to reach the ideal optimum. However, we still expect the system to have a higher probability of reaching a state with a higher value of the proposed indirect measure of fitness. In systems of many components, this implies that the largest deviations are expected in those components with less impact on the indirect measure of fitness. Here, we show that this simple probabilistic rule explains deviations from optimality in two very different biological systems. In Caenorhabditis elegans, this rule successfully explains the experimental deviations of the position of neurons from the configuration of minimal wiring cost. In Escherichia coli, the probabilistic rule correctly obtains the structure of the experimental deviations of metabolic fluxes from the configuration that maximizes biomass production. This approach is proposed to explain or predict more data than optimization theory while using no extra parameters. Thus, it can also be used to find and refine hypotheses about which constraints have shaped biological structures in evolution. PMID:19918070
Fang, H. Z.; Shang, S. L.; Wang, Y.; Liu, Z. K.; Alfonso, D.; Alman, D. E.; Shin, Y. K.; Zou, C. Y.; Duin, A. C. T. van; Lei, Y. K.; Wang, G. F.
2014-01-28
This paper is concerned with the prediction of oxygen diffusivities in fcc nickel from first-principles calculations and large-scale atomic simulations. Considering only the interstitial octahedral to tetrahedral to octahedral minimum energy pathway for oxygen diffusion in fcc lattice, greatly underestimates the migration barrier and overestimates the diffusivities by several orders of magnitude. The results indicate that vacancies in the Ni-lattice significantly impact the migration barrier of oxygen in nickel. Incorporation of the effect of vacancies results in predicted diffusivities consistent with available experimental data. First-principles calculations show that at high temperatures the vacancy concentration is comparable to the oxygen solubility, and there is a strong binding energy and a redistribution of charge density between the oxygen atom and vacancy. Consequently, there is a strong attraction between the oxygen and vacancy in the Ni lattice, which impacts diffusion.
NASA Astrophysics Data System (ADS)
Osei-Kuffuor, Daniel; Fattebert, Jean-Luc
2014-01-01
We present the first truly scalable first-principles molecular dynamics algorithm with O(N) complexity and controllable accuracy, capable of simulating systems with finite band gaps of sizes that were previously impossible with this degree of accuracy. By avoiding global communications, we provide a practical computational scheme capable of extreme scalability. Accuracy is controlled by the mesh spacing of the finite difference discretization, the size of the localization regions in which the electronic wave functions are confined, and a cutoff beyond which the components of the overlap matrix can be omitted when computing selected elements of its inverse. We demonstrate the algorithm's excellent parallel scaling for up to 101 952 atoms on 23 328 processors, with a wall-clock time of the order of 1 min per molecular dynamics time step and numerical error on the forces of less than 7×10-4 Ha/Bohr.
Osei-Kuffuor, Daniel; Fattebert, Jean-Luc
2014-01-01
We present the first truly scalable first-principles molecular dynamics algorithm with O(N) complexity and controllable accuracy, capable of simulating systems with finite band gaps of sizes that were previously impossible with this degree of accuracy. By avoiding global communications, we provide a practical computational scheme capable of extreme scalability. Accuracy is controlled by the mesh spacing of the finite difference discretization, the size of the localization regions in which the electronic wave functions are confined, and a cutoff beyond which the components of the overlap matrix can be omitted when computing selected elements of its inverse. We demonstrate the algorithm's excellent parallel scaling for up to 101 952 atoms on 23 328 processors, with a wall-clock time of the order of 1 min per molecular dynamics time step and numerical error on the forces of less than 7x10^{-4} Ha/Bohr.
NASA Astrophysics Data System (ADS)
Lindsay, L.; Broido, D. A.; Reinecke, T. L.
2013-10-01
The interplay between phonon-isotope and phonon-phonon scattering in determining lattice thermal conductivities in semiconductors and insulators is examined using an ab initio Boltzmann transport equation approach. We identify materials with large enhancements to their thermal conductivities with isotopic purification, known as the isotope effect, and we focus in particular on results for beryllium-VI compounds and cubic germanium carbide. We find that germanium carbide and beryllium selenide have very large room temperature isotope effects of 450%, far larger than in any other material. Thus, isotopic purification in these materials gives surprisingly high intrinsic room temperature thermal conductivities, over 1500 Wm-1 K-1 for germanium carbide and over 600 Wm-1 K-1 for beryllium selenide, well above those of the best metals. In compound semiconductors, a large mass ratio of the constituent atoms and large isotope mixture for the heavier atom gives enhanced isotope scattering. A frequency gap between acoustic and optic phonons (also due to a large mass ratio) and bunching of the acoustic phonon branches give weak anharmonic scattering. Combined, weak anharmonic phonon scattering and strong isotope scattering give a large isotope effect in the materials examined here. The physical insights discussed in this work will help guide the efficient manipulation of thermal transport properties of compound semiconductors through isotopic modification.
Nasal Septal Deviation and Facial Skeletal Asymmetries.
Hartman, Christopher; Holton, Nathan; Miller, Steven; Yokley, Todd; Marshall, Steven; Srinivasan, Sreedevi; Southard, Thomas
2016-03-01
During ontogeny, the nasal septum exerts a morphogenetic influence on the surrounding facial skeleton. While the influence of the septum is well established in long snouted animal models, its role in human facial growth is less clear. If the septum is a facial growth center in humans, we would predict that deviated septal growth would be associated with facial skeletal asymmetries. Using computed tomographic (CT) scans of n = 55 adult subjects, the purpose of this study was to test whether there is a correlation between septal deviation and facial asymmetries using three-dimensional (3D) geometric morphometric techniques. We calculated deviation as a percentage of septal volume relative to the volume of a modeled non-deviated septum. We then recorded skeletal landmarks representing the nasal, palatal, and lateral facial regions. Landmark data were superimposed using Procrustes analysis. First, we examined the correlation between nasal septal deviation and the overall magnitude of asymmetry. Next, we assessed whether there was a relationship between nasal septal deviation and more localized aspects of asymmetry using multivariate regression analysis. Our results indicate that while there was no correlation between septal deviation and the overall magnitude of asymmetry, septal deviation was associated with asymmetry primarily in the nasal floor and the palatal region. Septal deviation was unassociated with asymmetries in the lateral facial skeleton. Though we did not test the causal relationship between nasal septal deviation and facial asymmetry, our results suggest that the nasal septum may have an influence on patterns of adult facial form. PMID:26677010
A Scalable O(N) Algorithm for Large-Scale Parallel First-Principles Molecular Dynamics Simulations
Osei-Kuffuor, Daniel; Fattebert, Jean-Luc
2014-01-01
Traditional algorithms for first-principles molecular dynamics (FPMD) simulations only gain a modest capability increase from current petascale computers, due to their O(N^{3}) complexity and their heavy use of global communications. To address this issue, we are developing a truly scalable O(N) complexity FPMD algorithm, based on density functional theory (DFT), which avoids global communications. The computational model uses a general nonorthogonal orbital formulation for the DFT energy functional, which requires knowledge of selected elements of the inverse of the associated overlap matrix. We present a scalable algorithm for approximately computing selected entries of the inverse of the overlap matrix, based on an approximate inverse technique, by inverting local blocks corresponding to principal submatrices of the global overlap matrix. The new FPMD algorithm exploits sparsity and uses nearest neighbor communication to provide a computational scheme capable of extreme scalability. Accuracy is controlled by the mesh spacing of the finite difference discretization, the size of the localization regions in which the electronic orbitals are confined, and a cutoff beyond which the entries of the overlap matrix can be omitted when computing selected entries of its inverse. We demonstrate the algorithm's excellent parallel scaling for up to O(100K) atoms on O(100K) processors, with a wall-clock time of O(1) minute per molecular dynamics time step.
Large deviations of Rouse polymer chain: First passage problem
NASA Astrophysics Data System (ADS)
Cao, Jing; Zhu, Jian; Wang, Zuowei; Likhtman, Alexei E.
2015-11-01
The purpose of this paper is to investigate several analytical methods of solving first passage (FP) problem for the Rouse model, a simplest model of a polymer chain. We show that this problem has to be treated as a multi-dimensional Kramers' problem, which presents rich and unexpected behavior. We first perform direct and forward-flux sampling (FFS) simulations and measure the mean first-passage time τ(z) for the free end to reach a certain distance z away from the origin. The results show that the mean FP time is getting faster if the Rouse chain is represented by more beads. Two scaling regimes of τ(z) are observed, with transition between them varying as a function of chain length. We use these simulation results to test two theoretical approaches. One is a well known asymptotic theory valid in the limit of zero temperature. We show that this limit corresponds to fully extended chain when each chain segment is stretched, which is not particularly realistic. A new theory based on the well known Freidlin-Wentzell theory is proposed, where dynamics is projected onto the minimal action path. The new theory predicts both scaling regimes correctly, but fails to get the correct numerical prefactor in the first regime. Combining our theory with the FFS simulations leads us to a simple analytical expression valid for all extensions and chain lengths. One of the applications of polymer FP problem occurs in the context of branched polymer rheology. In this paper, we consider the arm-retraction mechanism in the tube model, which maps exactly on the model we have solved. The results are compared to the Milner-McLeish theory without constraint release, which is found to overestimate FP time by a factor of 10 or more.
Large Deviation Statistics of Vorticity Stretching in Isotropic Turbulence
NASA Astrophysics Data System (ADS)
Johnson, Perry; Meneveau, Charles
2015-11-01
A key feature of 3D fluid turbulence is the stretching/re-alignment of vorticity by the action of the strain-rate. It is shown using the cumulant-generating function that cumulative vorticity stretching along a Lagrangian path in isotropic turbulence behaves statistically like a sum of i.i.d. variables. The Cramer function for vorticity stretching is computed from the JHTDB isotropic DNS (Reλ = 430) and compared to those of the finite-time Lyapunov exponents (FTLE) for material deformation. As expected the mean cumulative vorticity stretching is slightly less than that of the most-stretched material line (largest FTLE), due to the vorticity's preferential alignment with the second-largest eigenvalue of strain-rate and the material line's preferential alignment with the largest eigenvalue. However, the vorticity stretching tends to be significantly larger than the second-largest FTLE, and the Cramer functions reveal that the statistics of vorticity stretching fluctuations are more similar to those of largest FTLE. A model Fokker-Planck equation is constructed by approximating the viscous destruction of vorticity with a deterministic non-linear relaxation law matching conditional statistics, while the fluctuations in vorticity stretching are modelled by stochastic noise matching the statistics encoded in the Cramer function. The model predicts a stretched-exponential tail for the vorticity magnitude PDF, with good agreement for the exponent but significant error (30-40%) in the pre-factor. Supported by NSF Graduate Fellowship (DGE-1232825) and NSF Grant CMMI-0941530.
Large deviations of Rouse polymer chain: First passage problem.
Cao, Jing; Zhu, Jian; Wang, Zuowei; Likhtman, Alexei E
2015-11-28
The purpose of this paper is to investigate several analytical methods of solving first passage (FP) problem for the Rouse model, a simplest model of a polymer chain. We show that this problem has to be treated as a multi-dimensional Kramers' problem, which presents rich and unexpected behavior. We first perform direct and forward-flux sampling (FFS) simulations and measure the mean first-passage time τ(z) for the free end to reach a certain distance z away from the origin. The results show that the mean FP time is getting faster if the Rouse chain is represented by more beads. Two scaling regimes of τ(z) are observed, with transition between them varying as a function of chain length. We use these simulation results to test two theoretical approaches. One is a well known asymptotic theory valid in the limit of zero temperature. We show that this limit corresponds to fully extended chain when each chain segment is stretched, which is not particularly realistic. A new theory based on the well known Freidlin-Wentzell theory is proposed, where dynamics is projected onto the minimal action path. The new theory predicts both scaling regimes correctly, but fails to get the correct numerical prefactor in the first regime. Combining our theory with the FFS simulations leads us to a simple analytical expression valid for all extensions and chain lengths. One of the applications of polymer FP problem occurs in the context of branched polymer rheology. In this paper, we consider the arm-retraction mechanism in the tube model, which maps exactly on the model we have solved. The results are compared to the Milner-McLeish theory without constraint release, which is found to overestimate FP time by a factor of 10 or more. PMID:26627948
48 CFR 1001.404 - Class deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Class deviations. 1001.404 Section 1001.404 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY GENERAL DEPARTMENT OF THE TREASURY ACQUISITION REGULATION (DTAR) SYSTEM Deviations from the FAR 1001.404 Class...
48 CFR 1001.403 - Individual deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Individual deviations. 1001.403 Section 1001.403 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY GENERAL DEPARTMENT OF THE TREASURY ACQUISITION REGULATION (DTAR) SYSTEM Deviations from the FAR 1001.403...
Code of Federal Regulations, 2014 CFR
2014-07-01
... 34 Education 1 2014-07-01 2014-07-01 false Deviations. 74.4 Section 74.4 Education Office of the Secretary, Department of Education ADMINISTRATION OF GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 74.4 Deviations. The Secretary, after consultation with the Office of...
Code of Federal Regulations, 2012 CFR
2012-07-01
... 34 Education 1 2012-07-01 2012-07-01 false Deviations. 74.4 Section 74.4 Education Office of the Secretary, Department of Education ADMINISTRATION OF GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 74.4 Deviations. The Secretary,...
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 1 2013-10-01 2013-10-01 false Deviations. 19.4 Section 19.4 Transportation Office of the Secretary of Transportation UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 19.4 Deviations. The Office of Management and Budget...
Code of Federal Regulations, 2013 CFR
2013-04-01
... 22 Foreign Relations 2 2013-04-01 2009-04-01 true Deviations. 518.4 Section 518.4 Foreign Relations BROADCASTING BOARD OF GOVERNORS UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 518.4 Deviations. The Office of Management and Budget...
Code of Federal Regulations, 2011 CFR
2011-04-01
... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Deviations. 518.4 Section 518.4 Foreign Relations BROADCASTING BOARD OF GOVERNORS UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 518.4 Deviations....
Code of Federal Regulations, 2012 CFR
2012-04-01
... 22 Foreign Relations 2 2012-04-01 2009-04-01 true Deviations. 518.4 Section 518.4 Foreign Relations BROADCASTING BOARD OF GOVERNORS UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 518.4 Deviations....
Code of Federal Regulations, 2011 CFR
2011-04-01
... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Deviations. 145.4 Section 145.4 Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 145.4 Deviations. The Office of Management...
Code of Federal Regulations, 2013 CFR
2013-04-01
... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Deviations. 145.4 Section 145.4 Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 145.4 Deviations. The Office of Management...
Code of Federal Regulations, 2013 CFR
2013-04-01
... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Deviations. 435.4 Section 435.4 Employees' Benefits SOCIAL SECURITY ADMINISTRATION UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, OTHER NON-PROFIT ORGANIZATIONS, AND COMMERCIAL ORGANIZATIONS General § 435.4 Deviations. The...
Code of Federal Regulations, 2014 CFR
2014-04-01
... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Deviations. 145.4 Section 145.4 Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 145.4 Deviations. The Office of Management and Budget (OMB) may grant exceptions for classes...
Code of Federal Regulations, 2014 CFR
2014-04-01
... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Deviations. 518.4 Section 518.4 Foreign Relations BROADCASTING BOARD OF GOVERNORS UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 518.4 Deviations....
48 CFR 1901.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... BROADCASTING BOARD OF GOVERNORS ACQUISITION REGULATION SYSTEM Deviations From the FAR 1901.404 Class deviations... Procurement Executive, unless FAR 1.405(e) is applicable, and shall be subject to the limitations set forth in FAR 1.404. Requests shall include the same information as cited in 1901.403....
48 CFR 1201.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... Executive Service (SES) official or that of a Flag Officer, may authorize individual deviations (unless (FAR) 48 CFR 1.405(e) applies). However, see TAM 1201.403. ... FEDERAL ACQUISITION REGULATIONS SYSTEM 70-Deviations From the FAR and TAR 1201.403 Individual...
48 CFR 3001.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... is authorized to approve FAR class deviations, except (FAR) 48 CFR 30.201-3, and 30.201-4 (the requirements of the Cost Accounting Standards Board); 48 CFR Chapter 99 (FAR Appendix); and part 50. Prior to... class deviation requests shall be submitted to the CPO per (HSAR) 48 CFR subpart 3001.70...
Code of Federal Regulations, 2010 CFR
2010-07-01
... 34 Education 1 2010-07-01 2010-07-01 false Deviations. 74.4 Section 74.4 Education Office of the Secretary, Department of Education ADMINISTRATION OF GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 74.4 Deviations. The Secretary,...
Code of Federal Regulations, 2010 CFR
2010-04-01
... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Deviations. 145.4 Section 145.4 Foreign Relations DEPARTMENT OF STATE CIVIL RIGHTS GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General § 145.4 Deviations. The Office of Management...
48 CFR 2001.403 - Individual deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Individual deviations. 2001.403 Section 2001.403 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION GENERAL NUCLEAR REGULATORY COMMISSION ACQUISITION REGULATION SYSTEM Deviations From the FAR and the NRCAR...
48 CFR 2001.404 - Class deviations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Class deviations. 2001.404 Section 2001.404 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION GENERAL NUCLEAR REGULATORY COMMISSION ACQUISITION REGULATION SYSTEM Deviations From the FAR and the NRCAR 2001.404...
Code of Federal Regulations, 2010 CFR
2010-01-01
... would be a deviation from 10 CFR part 600, the deviation must also be authorized in accordance with the... ENERGY (CONTINUED) ASSISTANCE REGULATIONS THE OFFICE OF ENERGY RESEARCH FINANCIAL ASSISTANCE PROGRAM... or Deputy Director of ER or the Head of a Contracting Activity upon the written request of DOE...
Code of Federal Regulations, 2010 CFR
2010-01-01
... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false Deviations. 215.4 Section 215.4 Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET CIRCULARS AND GUIDANCE Reserved UNIFORM ADMINISTRATIVE... ORGANIZATIONS (OMB CIRCULAR A-110) General § 215.4 Deviations. The Office of Management and Budget (OMB)...
Code of Federal Regulations, 2010 CFR
2010-07-01
... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Deviation. 105-1.110 Section 105-1.110 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 1-INTRODUCTION 1.1-Regulations System § 105-1.110 Deviation....
48 CFR 2901.404 - Class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... through the Director, DAMS. (b) Requests for deviations under paragraph (a) of this section must be... contracting actions which will be affected. (c) For a FAR class deviation the Director, DAMS will consult with... Director, DAMS as required in FAR 1.404....
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Deviations. 609.18 Section 609.18 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS LOAN GUARANTEES FOR PROJECTS THAT EMPLOY INNOVATIVE TECHNOLOGIES § 609.18 Deviations. To the extent that such requirements are not specified by the Act or other applicable statutes, DOE may authorize...
Management of mandibular deviation after mandibulectomy by simplified approach.
Arora, Varuni; Singh, Kamleshwar; Agrawal, Kaushal Kishor; Alvi, Habib Ahmed
2013-01-01
Unfavourable sequelae from mandibular surgeries include malocclusion and temporomandibular joint dysfunction. The management of the situation before these complications arise is largely based on experience. This report presents a case where mandibular deviation is decreased through an additional row of teeth in the maxillary removable partial denture, and by decreasing scar contracture in the surgical site by means of a simple exercise. PMID:23625665
Large perpendicular magnetic anisotropy of single Co atom on MgO monolayer: A first-principles study
Shao, Bin; Shi, Wu-Jun; Feng, Min; Zuo, Xu
2015-05-07
Realizing the magnetic bit with a single atom is the ultimate goal for magnetic storage. Based on density functional theory, the magnetic anisotropy (MA) of single Co atom on MgO monolayer has been investigated. Results show that this two dimensional system possesses a large perpendicular MA, about 5.8 meV per Co atom. Besides, there exists remarkable unquenched orbital moments for different magnetization directions, which can be attributed to the reduction of coordination number in two dimensional system and is responsible for the enhanced MA. The Bloch pseudo-wavefunction and band structure of Co d-orbitals have been calculated to elucidate the origin of the perpendicular MA.
Raypath deviation under stable and unstable conditions
NASA Astrophysics Data System (ADS)
Dion, Denis; Seiffer, Dirk; Stein, Karin; Forand, Luc; Potvin, Guy
2005-10-01
Ray-bending resulting from atmospheric refraction in the maritime environment has been shown to potentially produce significant effects on electro-optical target detection and imaging. Positive bending makes possible detection beyond the horizon while negative bending reduces the maximum inter-vision range (MIVR) and is likely to produce severe image distortion or mirages. It has been shown by many authors that these phenomena can be efficiently described using ray-tracing in conjunction with bulk estimations of the refractivity profiles based on the Monin-Obhukov theory. In this paper, the accuracy of bulk methods to describe ray bending is assessed by examining angular deviations of apparent target elevations with respect to the meteorological conditions. Prediction accuracy is shown for a large spectrum of conditions, characterized by the air-sea temperature difference, by combining measurements collected in the North Sea and in the Baltic Sea. Moreover, the use of bulk profiles as opposed to profiles measured at sea by using a buoy is discussed.
NASA Astrophysics Data System (ADS)
Miller, E. K.
There is a growing need to determine the electromagnetic performance of increasingly complex systems at ever higher frequencies. The ideal approach would be some appropriate combination of measurement, analysis, and computation so that system design and assessment can be achieved to a needed degree of accuracy at some acceptable cost. Both measurement and computation benefit from the continuing growth in computer power that, since the early 1950s, has increased by a factor of more than a million in speed and storage. For example, a CRAY2 has an effective throughput (not the clock rate) of about 10(exp 11) floating point operations (FLOPs) per hour compared with the approx. 10(exp 5) provided by the UNIVAC-1. The purpose of this discussion is to illustrate the computational complexity of modeling large (in wavelengths) electromagnetic problems. In particular the point is made that simply relying on faster computers for increasing the size and complexity of problems that can be modeled is less effective than might be anticipated from this raw increase in computer throughput. It is suggested that rather than depending on faster computers alone, various analytical and numerical alternatives need development for reducing the overall FLOP count required to acquire the information desired. One approach is to decrease the operation count of the basic model computation itself, by reducing the order of the frequency dependence of the various numerical operations or their multiplying coefficients. Another is to decrease the number of model evaluations that are needed, an example being the number of frequency samples required to define a wideband response, by using an auxiliary model of the expected behavior.
Scaling Deviations for Neutrino Reactions in Aysmptotically Free Field Theories
DOE R&D Accomplishments Database
Wilczek, F. A.; Zee, A.; Treiman, S. B.
1974-11-01
Several aspects of deep inelastic neutrino scattering are discussed in the framework of asymptotically free field theories. We first consider the growth behavior of the total cross sections at large energies. Because of the deviations from strict scaling which are characteristic of such theories the growth need not be linear. However, upper and lower bounds are established which rather closely bracket a linear growth. We next consider in more detail the expected pattern of scaling deviation for the structure functions and, correspondingly, for the differential cross sections. The analysis here is based on certain speculative assumptions. The focus is on qualitative effects of scaling breakdown as they may show up in the X and y distributions. The last section of the paper deals with deviations from the Callan-Gross relation.
The influence of geology on blasthole deviation
Singh, S.P.
1996-12-31
Blasthole deviation is a frequent, well documented and undesirable occurrence in mining operations. It is caused by the drill string mechanics, operating variables and the interaction between the drill bit and the rock mass characteristics. It is composed of three distinct components: collaring or marking error, alignment error and trajectory deviation. This study has focused on the dependence of trajectory or natural deviation on the geological features of the rock mass being drilled. The methodology involved the study of visible half barrels at road cuts, open pits, quarries, underground drifting and breasting operations. The effects of the following geological features on drillhole deviation have been investigated and discussed in this paper (1) strength and hardness of rocks (2) alternate layers of hard and soft rocks (3) anisotropy in rock mass (4) thickness and inclination of layers and bedding planes and (5) joints or other geological boundaries.
Tertiary recovery method using inverted deviated holes
Goodhart, M.E.
1987-03-13
A method is described of recovering oil and the like from a subsurface earth formation comprising the steps of: establishing a substantially vertical shaft hole extending from the surface of the earth of the subsurface earth formation, boring from the vertical shaft initially in an essentially upward direction in the formation at least one deviated hole in the formation, the deviated hole having an upper end and communicating at its lower end with the vertical shaft, forming from an upper end in the vertical shaft in an essentially downward direction an outer borehole in the subsurface earth formation in proximity with the deviated hole, the outer borehole communicating with the vertical shaft and horizontally overlapping the deviated hole, and directing recovery enhancing fluids from the surface through the upper end of the vertical shaft to the outer borehole and injecting the fluids into the formation in proximity with the deviated hole whereby the fluids injected into the earth formation in proximity with the hole facilitates drainage of oil and the like into the upwardly directed deviated hole.
Role of Extracorporeal Septoplasty in Deviated Noses.
Ghaisas, Virendra; Parab, Sapna Ramkrishna
2015-09-01
Severe gross septal deviations present big surgical challenges for operating surgeon. Septal deviations has direct effect on aesthetic and functional part of nose. Correcting septal deviations during rhinoplasty is basic procedure. Extreme deviations of septum especially on dorsal and caudal end of cartilaginous septum are difficult to treat. The classical septoplasty approach becomes unsuitable for such severe deviations. Gubisch has first reported in 1995 about extracorporeal septoplasty. To report the experience of Extracorporeal septoplasty and the complication rates with the technique. Retrospective study of 112 patients who underwent extracorporeal septoplasty in primary rhinoplasty from May 2009 to June 2014. Patient's pre and postoperatively evaluation was done by photographs, nasal endoscopy and subjective by symptoms evaluation satisfaction scale 6 and 12 months postoperatively. Nasal endoscopy revealed significant improvement in nasal airway and nasal valve and subjective evaluation satisfaction score was very encouraging. Complications like septal perforation, bleeding, aesthetic complications were minimal (9 %) On basis of results obtained, shows that this technique, increases patients nasal airway and aesthetic look of the patients. Irrespective of extreme nasal deviations. PMID:26405652
Attacks exploiting deviation of mean photon number in quantum key distribution and coin tossing
NASA Astrophysics Data System (ADS)
Sajeed, Shihan; Radchenko, Igor; Kaiser, Sarah; Bourgoin, Jean-Philippe; Pappa, Anna; Monat, Laurent; Legré, Matthieu; Makarov, Vadim
2015-03-01
The security of quantum communication using a weak coherent source requires an accurate knowledge of the source's mean photon number. Finite calibration precision or an active manipulation by an attacker may cause the actual emitted photon number to deviate from the known value. We model effects of this deviation on the security of three quantum communication protocols: the Bennett-Brassard 1984 (BB84) quantum key distribution (QKD) protocol without decoy states, Scarani-Acín-Ribordy-Gisin 2004 (SARG04) QKD protocol, and a coin-tossing protocol. For QKD we model both a strong attack using technology possible in principle and a realistic attack bounded by today's technology. To maintain the mean photon number in two-way systems, such as plug-and-play and relativistic quantum cryptography schemes, bright pulse energy incoming from the communication channel must be monitored. Implementation of a monitoring detector has largely been ignored so far, except for ID Quantique's commercial QKD system Clavis2. We scrutinize this implementation for security problems and show that designing a hack-proof pulse-energy-measuring detector is far from trivial. Indeed, the first implementation has three serious flaws confirmed experimentally, each of which may be exploited in a cleverly constructed Trojan-horse attack. We discuss requirements for a loophole-free implementation of the monitoring detector.
Online Deviation Detection for Medical Processes
Christov, Stefan C.; Avrunin, George S.; Clarke, Lori A.
2014-01-01
Human errors are a major concern in many medical processes. To help address this problem, we are investigating an approach for automatically detecting when performers of a medical process deviate from the acceptable ways of performing that process as specified by a detailed process model. Such deviations could represent errors and, thus, detecting and reporting deviations as they occur could help catch errors before harm is done. In this paper, we identify important issues related to the feasibility of the proposed approach and empirically evaluate the approach for two medical procedures, chemotherapy and blood transfusion. For the evaluation, we use the process models to generate sample process executions that we then seed with synthetic errors. The process models describe the coordination of activities of different process performers in normal, as well as in exceptional situations. The evaluation results suggest that the proposed approach could be applied in clinical settings to help catch errors before harm is done. PMID:25954343
Fatigue, pilot deviations and time of day
NASA Technical Reports Server (NTRS)
Baker, Susan P.
1989-01-01
The relationships between pilot fatigue, pilot deviations, reported incidents, and time of day are examined. A sample of 200 Aviation Safety Reporting System (ASRS) reports were analyzed from 1985 and 200 reports from 1987, plus 100 reports from late 1987 and early 1988 that were selected because of possible association with fatigue. The FAA pilot deviation data and incident data were analyzed in relation to denominator data that summarized the hourly operations (landings and takeoffs of scheduled flights) at major U.S. airports. Using as numerators FAA data on pilot deviations and incidents reported to the FAA, the rates by time of day were calculated. Pilot age was also analyzed in relation to the time of day, phase of flight, and type of incident.
ERIC Educational Resources Information Center
Hewitt, Paul G.
2004-01-01
Some teachers have difficulty understanding Bernoulli's principle particularly when the principle is applied to the aerodynamic lift. Some teachers favor using Newton's laws instead of Bernoulli's principle to explain the physics behind lift. Some also consider Bernoulli's principle too difficult to explain to students and avoid teaching it…
Code of Federal Regulations, 2012 CFR
2012-04-01
... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Deviations. 435.4 Section 435.4 Employees' Benefits SOCIAL SECURITY ADMINISTRATION UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, OTHER NON-PROFIT ORGANIZATIONS, AND COMMERCIAL...
Code of Federal Regulations, 2012 CFR
2012-10-01
... 49 Transportation 1 2012-10-01 2012-10-01 false Deviations. 19.4 Section 19.4 Transportation Office of the Secretary of Transportation UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS General §...
48 CFR 3001.403 - Individual deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... CFR 30.201-3, 30.201-4; the requirements of the Cost Accounting Standards board rules and regulations at 48 CFR chapter 99 (FAR appendix); and part 50). Submit requests per (HSAR) 48 CFR 3001.7000... from the FAR and HSAR 3001.403 Individual deviations. Unless precluded by law, executive order,...
41 CFR 109-1.5304 - Deviations.
Code of Federal Regulations, 2011 CFR
2011-01-01
... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle...
41 CFR 109-1.5304 - Deviations.
Code of Federal Regulations, 2012 CFR
2012-01-01
... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle...
41 CFR 109-1.5304 - Deviations.
Code of Federal Regulations, 2013 CFR
2013-07-01
... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle...
48 CFR 201.404 - Class deviations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... Air Force, and the Directors of the Defense Commissary Agency, the Defense Contract Management Agency, and the Defense Logistics Agency, may approve any class deviation, other than those described in 201... department or agency; (B) Have a significant cost or administrative impact on contractors or offerors;...
48 CFR 201.404 - Class deviations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... Air Force, and the Directors of the Defense Commissary Agency, the Defense Contract Management Agency, and the Defense Logistics Agency, may approve any class deviation, other than those described in 201... department or agency; (B) Have a significant cost or administrative impact on contractors or offerors;...
Manifestations of Deviation in the Adolescent Subculture
ERIC Educational Resources Information Center
Sobkin, V. S.; Abrosimova, Z. B.; Adamchuk, D. V.; Baranova, E. V.
2005-01-01
In this article the authors look at questions relating to school students' attitudes toward types of deviation such as smoking and the use of alcohol and narcotics. The empirical material is divided into the following topics: how widespread these forms of behavior are; motives that cause adolescents to start smoking, using alcohol, and taking…
Code of Federal Regulations, 2010 CFR
2010-04-01
... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Deviations. 435.4 Section 435.4 Employees' Benefits SOCIAL SECURITY ADMINISTRATION UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND AGREEMENTS WITH... will be permitted only in unusual circumstances. SSA may apply more restrictive requirements to a...
41 CFR 109-1.5304 - Deviations.
Code of Federal Regulations, 2010 CFR
2010-07-01
... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle...
Code of Federal Regulations, 2011 CFR
2011-07-01
... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Deviation. 101-1.110 Section 101-1.110 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.110...
Code of Federal Regulations, 2012 CFR
2012-07-01
... 41 Public Contracts and Property Management 2 2012-07-01 2012-07-01 false Deviation. 101-1.110 Section 101-1.110 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.110...
Code of Federal Regulations, 2010 CFR
2010-07-01
... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Deviation. 101-1.110 Section 101-1.110 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.110...
Code of Federal Regulations, 2014 CFR
2014-07-01
... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Deviation. 101-1.110 Section 101-1.110 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.110...
Code of Federal Regulations, 2012 CFR
2012-01-01
...” within the meaning of the Paperwork Reduction Act (44 U.S.C. 35) and its implementation in 5 CFR part... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Deviations. 1260.7 Section 1260.7 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS...
Code of Federal Regulations, 2010 CFR
2010-01-01
...” within the meaning of the Paperwork Reduction Act (44 U.S.C. 35) and its implementation in 5 CFR part... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Deviations. 1260.7 Section 1260.7 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS...
Code of Federal Regulations, 2011 CFR
2011-01-01
...” within the meaning of the Paperwork Reduction Act (44 U.S.C. 35) and its implementation in 5 CFR part... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Deviations. 1260.7 Section 1260.7 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS...
Code of Federal Regulations, 2014 CFR
2014-01-01
...” within the meaning of the Paperwork Reduction Act (44 U.S.C. 35) and its implementation in 5 CFR part... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Deviations. Â§ 1260.7 Section Â§ 1260.7 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS...
Code of Federal Regulations, 2013 CFR
2013-01-01
...” within the meaning of the Paperwork Reduction Act (44 U.S.C. 35) and its implementation in 5 CFR part... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Deviations. 1260.7 Section 1260.7 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS...
Bodily Deviations and Body Image in Adolescence
ERIC Educational Resources Information Center
Vilhjalmsson, Runar; Kristjansdottir, Gudrun; Ward, Dianne S.
2012-01-01
Adolescents with unusually sized or shaped bodies may experience ridicule, rejection, or exclusion based on their negatively valued bodily characteristics. Such experiences can have negative consequences for a person's image and evaluation of self. This study focuses on the relationship between bodily deviations and body image and is based on a…
Code of Federal Regulations, 2013 CFR
2013-01-01
... 7 Agriculture 15 2013-01-01 2013-01-01 false Deviations. 2502.3 Section 2502.3 Agriculture Regulations of the Department of Agriculture (Continued) OFFICE OF ADVOCACY AND OUTREACH, DEPARTMENT OF AGRICULTURE AGRICULTURAL CAREER AND EMPLOYMENT (ACE) GRANTS PROGRAM General Information § 2502.3...
NASA Astrophysics Data System (ADS)
Deng, Hui-Xiong; Li, Jingbo; Li, Shu-Shen; Peng, Haowei; Xia, Jian-Bai; Wang, Lin-Wang; Wei, Su-Huai
2010-11-01
For large size- and chemical-mismatched isovalent semiconductor alloys, such as N and Bi substitution on As sites in GaAs, isovalent defect levels or defect bands are introduced. The evolution of the defect states as a function of the alloy concentration is usually described by the popular phenomenological band anticrossing (BAC) model. Using first-principles band-structure calculations we show that at the impurity limit the N- (Bi)-induced impurity level is above (below) the conduction- (valence-) band edge of GaAs. These trends reverse at high concentration, i.e., the conduction-band edge of GaAs1-xNx becomes an N-derived state and the valence-band edge of GaAs1-xBix becomes a Bi-derived state, as expected from their band characters. We show that this band crossing phenomenon cannot be described by the popular BAC model but can be naturally explained by a simple band broadening picture.
NASA Technical Reports Server (NTRS)
Litvin, Faydor L.; Kuan, Chihping; Zhang, YI
1991-01-01
A numerical method is developed for the minimization of deviations of real tooth surfaces from the theoretical ones. The deviations are caused by errors of manufacturing, errors of installment of machine-tool settings and distortion of surfaces by heat-treatment. The deviations are determined by coordinate measurements of gear tooth surfaces. The minimization of deviations is based on the proper correction of initially applied machine-tool settings. The contents of accomplished research project cover the following topics: (1) Descriptions of the principle of coordinate measurements of gear tooth surfaces; (2) Deviation of theoretical tooth surfaces (with examples of surfaces of hypoid gears and references for spiral bevel gears); (3) Determination of the reference point and the grid; (4) Determination of the deviations of real tooth surfaces at the points of the grid; and (5) Determination of required corrections of machine-tool settings for minimization of deviations. The procedure for minimization of deviations is based on numerical solution of an overdetermined system of n linear equations in m unknowns (m much less than n ), where n is the number of points of measurements and m is the number of parameters of applied machine-tool settings to be corrected. The developed approach is illustrated with numerical examples.
Deviations from LTE in a stellar atmosphere
NASA Technical Reports Server (NTRS)
Kalkofen, W.; Klein, R. I.; Stein, R. F.
1979-01-01
Deviations for LTE are investigated in an atmosphere of hydrogen atoms with one bound level, satisfying the equations of radiative, hydrostatic, and statistical equilibrium. The departure coefficient and the kinetic temperature as functions of the frequency dependence of the radiative cross section are studied analytically and numerically. Near the outer boundary of the atmosphere, the departure coefficient is smaller than unity when the radiative cross section grows with frequency faster than with the square of frequency; it exceeds unity otherwise. Far from the boundary the departure coefficient tends to exceed unity for any frequency dependence of the radiative cross section. Overpopulation always implies that the kinetic temperature in the statistical-equilibrium atmosphere is higher than the temperature in the corresponding LTE atmosphere. Upper and lower bounds on the kinetic temperature are given for an atmosphere with deviations from LTE only in the optically shallow layers when the emergent intensity can be described by a radiation temperature.
Equivalence Principle and Gravitational Redshift
Hohensee, Michael A.; Chu, Steven; Mueller, Holger; Peters, Achim
2011-04-15
We investigate leading order deviations from general relativity that violate the Einstein equivalence principle in the gravitational standard model extension. We show that redshift experiments based on matter waves and clock comparisons are equivalent to one another. Consideration of torsion balance tests, along with matter-wave, microwave, optical, and Moessbauer clock tests, yields comprehensive limits on spin-independent Einstein equivalence principle-violating standard model extension terms at the 10{sup -6} level.
NASA Astrophysics Data System (ADS)
Areshkin, Denis A.; Nikolić, Branislav K.
2010-04-01
The recent fabrication of graphene nanoribbon (GNR) field-effect transistors poses a challenge for first-principles modeling of carbon nanoelectronics due to many thousand atoms present in the device. The state of the art quantum transport algorithms, based on the nonequilibrium Green function formalism combined with the density-functional theory (NEGF-DFT), were originally developed to calculate self-consistent electron density in equilibrium and at finite bias voltage (as a prerequisite to obtain conductance or current-voltage characteristics, respectively) for small molecules attached to metallic electrodes where only a few hundred atoms are typically simulated. Here we introduce combination of two numerically efficient algorithms which make it possible to extend the NEGF-DFT framework to device simulations involving large number of atoms. Our first algorithm offers an alternative to the usual evaluation of the equilibrium part of electron density via numerical contour integration of the retarded Green function in the upper complex half-plane. It is based on the replacement of the Fermi function f(E) with an analytic function f˜(E) coinciding with f(E) inside the integration range along the real axis, but decaying exponentially in the upper complex half-plane. Although f˜(E) has infinite number of poles, whose positions and residues are determined analytically, only a finite number of those poles have non-negligible residues. We also discuss how this algorithm can be extended to compute the nonequilibrium contribution to electron density, thereby evading cumbersome real-axis integration (within the bias voltage window) of NEGFs which is very difficult to converge for systems with large number of atoms while maintaining current conservation. Our second algorithm combines the recursive formulas with the geometrical partitioning of an arbitrary multiterminal device into nonuniform segments in order to reduce the computational complexity of the retarded Green
Note Onset Deviations as Musical Piece Signatures
Serrà, Joan; Özaslan, Tan Hakan; Arcos, Josep Lluis
2013-01-01
A competent interpretation of a musical composition presents several non-explicit departures from the written score. Timing variations are perhaps the most important ones: they are fundamental for expressive performance and a key ingredient for conferring a human-like quality to machine-based music renditions. However, the nature of such variations is still an open research question, with diverse theories that indicate a multi-dimensional phenomenon. In the present study, we consider event-shift timing variations and show that sequences of note onset deviations are robust and reliable predictors of the musical piece being played, irrespective of the performer. In fact, our results suggest that only a few consecutive onset deviations are already enough to identify a musical composition with statistically significant accuracy. We consider a mid-size collection of commercial recordings of classical guitar pieces and follow a quantitative approach based on the combination of standard statistical tools and machine learning techniques with the semi-automatic estimation of onset deviations. Besides the reported results, we believe that the considered materials and the methodology followed widen the testing ground for studying musical timing and could open new perspectives in related research fields. PMID:23935971
Note onset deviations as musical piece signatures.
Serrà, Joan; Özaslan, Tan Hakan; Arcos, Josep Lluis
2013-01-01
A competent interpretation of a musical composition presents several non-explicit departures from the written score. Timing variations are perhaps the most important ones: they are fundamental for expressive performance and a key ingredient for conferring a human-like quality to machine-based music renditions. However, the nature of such variations is still an open research question, with diverse theories that indicate a multi-dimensional phenomenon. In the present study, we consider event-shift timing variations and show that sequences of note onset deviations are robust and reliable predictors of the musical piece being played, irrespective of the performer. In fact, our results suggest that only a few consecutive onset deviations are already enough to identify a musical composition with statistically significant accuracy. We consider a mid-size collection of commercial recordings of classical guitar pieces and follow a quantitative approach based on the combination of standard statistical tools and machine learning techniques with the semi-automatic estimation of onset deviations. Besides the reported results, we believe that the considered materials and the methodology followed widen the testing ground for studying musical timing and could open new perspectives in related research fields. PMID:23935971
Geometry of river networks. I. Scaling, fluctuations, and deviations
Dodds, Peter Sheridan; Rothman, Daniel H.
2001-01-01
This paper is the first in a series of three papers investigating the detailed geometry of river networks. Branching networks are a universal structure employed in the distribution and collection of material. Large-scale river networks mark an important class of two-dimensional branching networks, being not only of intrinsic interest but also a pervasive natural phenomenon. In the description of river network structure, scaling laws are uniformly observed. Reported values of scaling exponents vary, suggesting that no unique set of scaling exponents exists. To improve this current understanding of scaling in river networks and to provide a fuller description of branching network structure, here we report a theoretical and empirical study of fluctuations about and deviations from scaling. We examine data for continent-scale river networks such as the Mississippi and the Amazon and draw inspiration from a simple model of directed, random networks. We center our investigations on the scaling of the length of a subbasin's dominant stream with its area, a characterization of basin shape known as Hack's law. We generalize this relationship to a joint probability density, and provide observations and explanations of deviations from scaling. We show that fluctuations about scaling are substantial, and grow with system size. We find strong deviations from scaling at small scales which can be explained by the existence of a linear network structure. At intermediate scales, we find slow drifts in exponent values, indicating that scaling is only approximately obeyed and that universality remains indeterminate. At large scales, we observe a breakdown in scaling due to decreasing sample space and correlations with overall basin shape. The extent of approximate scaling is significantly restricted by these deviations, and will not be improved by increases in network resolution.
Variability of Ocular Deviation in Strabismus
Economides, John R.; Adams, Daniel L.; Horton, Jonathan C.
2015-01-01
IMPORTANCE In strabismus, the fixating eye conveys the direction of gaze while the fellow eye points at a peripheral location in space. The stability of the eyes may be reduced by the absence of a common target. OBJECTIVE To quantify the stability of eye position in strabismus and to measure variability in the ocular deviation. DESIGN, SETTING, AND PARTICIPANTS From 2010 to 2014, a prospective comparative case study of 25 patients with alternating exotropia with normal visual acuity in each eye and 25 control individuals was conducted in a laboratory at a tertiary eye center. A video eye tracker was used to measure the position of each eye while participants alternated fixation on the center of a cross under dichoptic conditions or scanned pictures of natural scenes. MAIN OUTCOMES AND MEASURES Spatial and temporal variability in the position of the fixating eye and the nonfixating eye in patients with strabismus and control individuals, quantified by the log area of ellipses containing 95% of eye positions or mean SDs of eye position. RESULTS In the 25 patients with strabismus, the mean (SD) age was 28 (14) years (range, 8–55 years) and the mean (SD) ocular deviation was 14.2° (5.9°) (range, 4.4°–22.4°). In the patients with strabismus, the mean position variability (1.80 log units; 95% CI, 1.66–1.93) for the deviating eye was greater than for the fixating eye (1.26 log units; 95% CI, 1.17–1.35) (P < .001). The fixating eye of patients with strabismus was more variable in position than the fixating eye of individuals without strabismus (0.98 log units; 95% CI, 0.88–1.08) (P < .005). CONCLUSIONS AND RELEVANCE In patients with strabismus, even without amblyopia, the deviated eye is more variable in position than the fixating eye. Both eyes are less stable in position than the eyes of control individuals, which indicates that strabismus impairs the ability to fixate targets steadily. Saccades contribute to variability of the deviation angle because they
NASA Astrophysics Data System (ADS)
Pardo, Enric; Šouc, Ján; Frolek, Lubomir
2015-04-01
Many large-scale applications require electromagnetic modelling with extensive numerical computations, such as magnets or three-dimensional (3D) objects like transposed conductors or motors and generators. Therefore, it is necessary to develop computationally time-efficient but still accurate numerical methods. This article develops a general variational formalism for any {E}({J}) relation and applies it to model coated-conductor coils containing up to thousands of turns, taking magnetization currents fully into account. The variational principle, valid for any 3D situation, restricts the computations to the sample volume, reducing the computation time. However, no additional magnetic materials interacting with the superconductor are taken directly into account. Regarding the coil modelling, we use a power law E(J) relation with magnetic field-dependent critical current density, Jc, and power law exponent, n. We test the numerical model by comparing the results to analytical formulas for thin strips and experiments for stacks of pancake coils, finding a very good agreement. Afterwards, we model a magnet-size coil of 4000 turns (stack of 20 pancake coils of 200 turns each). We found that the ac loss is mainly due to magnetization currents. We also found that for an n exponent of 20, the magnetization currents are greatly suppressed after 1 h relaxation. In addition, in coated conductor coils magnetization currents have an important impact on the generated magnetic field; which should be taken into account for magnet design. In conclusion, the presented numerical method fulfills the requirements for electromagnetic design of coated conductor windings.
Standard deviation of scatterometer measurements from space.
NASA Technical Reports Server (NTRS)
Fischer, R. E.
1972-01-01
The standard deviation of scatterometer measurements has been derived under assumptions applicable to spaceborne scatterometers. Numerical results are presented which show that, with sufficiently long integration times, input signal-to-noise ratios below unity do not cause excessive degradation of measurement accuracy. The effects on measurement accuracy due to varying integration times and changing the ratio of signal bandwidth to IF filter-noise bandwidth are also plotted. The results of the analysis may resolve a controversy by showing that in fact statistically useful scatterometer measurements can be made from space using a 20-W transmitter, such as will be used on the S-193 experiment for Skylab-A.
Measuring and Plotting Surface-Contour Deviations
NASA Technical Reports Server (NTRS)
Aragon, Lino A.; Shuck, Thomas; Crockett, Leroy K.
1987-01-01
Hand-held device measures deviation of contour of surface from desired contour and provides output to x-y plotter. Carriage on device rolled along track representing desired contour, while spring-loaded stylus on device deflects perpendicularly to track to follow surface. Operator moves carriage of contour-measuring device on beamlike track. Stylus on carriage traces contour of surface above it. Carriage of measuring device holds transducer measuring cross-track displacement of surface from desired contour, and multiple-turn potentiometer measuring position along track.
NASA Astrophysics Data System (ADS)
Prins, Steven L.; Blatchford, James; Olubuyide, Oluwamuyiwa; Riley, Deborah; Chang, Simon; Hong, Qi-Zhong; Kim, T. S.; Borges, Ricardo; Lin, Li
2009-03-01
As design rules and corresponding logic standard cell layouts continue to shrink node-on-node in accordance with Moore's law, complex 2D interactions, both intra-cell and between cells, become much more prominent. For example, in lithography, lack of scaling of λ/NA implies aggressive use of resolution enhancement techniques to meet logic scaling requirements-resulting in adverse effects such as 'forbidden pitches'-and also implies an increasing range of optical influence relative to cell size. These adverse effects are therefore expected to extend well beyond the cell boundary, leading to lithographic marginalities that occur only when a given cell is placed "in context" with other neighboring cells in a variable design environment [1]. This context dependence is greatly exacerbated by increased use of strain engineering techniques such as SiGe and dual-stress liners (DSL) to enhance transistor performance, both of which also have interaction lengths on the order of microns. The use of these techniques also breaks the formerly straightforward connection between lithographic 'shapes' and end-of-line electrical performance, thus making the formulation of design rules that are robust to process variations and complex 2D interactions more difficult. To address these issues, we have developed a first-principles-based simulation flow to study contextdependent electrical effects in layout, arising not only from lithography, but also from stress and interconnect parasitic effects. This flow is novel in that it can be applied to relatively large layout clips- required for context-dependent analysis-without relying on semi-empirical or 'black-box' models for the fundamental electrical effects. The first-principles-based approach is ideal for understanding contextdependent effects early in the design phase, so that they can be mitigated through restrictive design rules. The lithographic simulations have been discussed elsewhere [1] and will not be presented in detail. The
48 CFR 2801.470 - Requests for class deviations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... DEPARTMENT OF JUSTICE ACQUISITION REGULATIONS SYSTEM Deviations From the FAR and JAR 2801.470 Requests for class deviations. Requests for approval of class deviations from the FAR or the JAR shall be forwarded... deviations shall be submitted as far in advance as the exigencies of the situation permit and shall...
Spotting deviations from R2 inflation
NASA Astrophysics Data System (ADS)
de la Cruz-Dombriz, Álvaro; Elizalde, Emilio; Odintsov, Sergei D.; Sáez-Gómez, Diego
2016-05-01
We discuss the soundness of inflationary scenarios in theories beyond the Starobinsky model, namely a class of theories described by arbitrary functions of the Ricci scalar and the K-essence field. We discuss the pathologies associated with higher-order equations of motion which will be shown to constrain the stability of this class of theories. We provide a general framework to calculate the slow-roll parameters and the corresponding mappings to the theory parameters. For paradigmatic gravitational models within the class of theories under consideration we illustrate the power of the Planck/Bicep2 latest results to constrain such gravitational Lagrangians. Finally, bounds for potential deviations from Starobinsky-like inflation are derived.
NASA Astrophysics Data System (ADS)
Lamport, Leslie
2012-08-01
Buridan's principle asserts that a discrete decision based upon input having a continuous range of values cannot be made within a bounded length of time. It appears to be a fundamental law of nature. Engineers aware of it can design devices so they have an infinitessimal probability of not making a decision quickly enough. Ignorance of the principle could have serious consequences.
ERIC Educational Resources Information Center
MacBeath, John; Swaffield, Sue; Frost, David
2009-01-01
This article provides an overview of the "Carpe Vitam: Leadership for Learning" project, accounting for its provenance and purposes, before focusing on the principles for practice that constitute an important part of the project's legacy. These principles framed the dialogic process that was a dominant feature of the project and are presented,…