Laplace Transforms without Integration
ERIC Educational Resources Information Center
Robertson, Robert L.
2017-01-01
Calculating Laplace transforms from the definition often requires tedious integrations. This paper provides an integration-free technique for calculating Laplace transforms of many familiar functions. It also shows how the technique can be applied to probability theory.
NASA Astrophysics Data System (ADS)
Plastino, A.; Rocca, M. C.
2013-11-01
We introduce here the q-Laplace transform as a new weapon in Tsallis’ arsenal, discussing its main properties and analyzing some examples. The q-Gaussian instance receives special consideration. Also, we derive the q-partition function from the q-Laplace transform.
Waveform inversion in the Laplace and Laplace-Fourier domains
NASA Astrophysics Data System (ADS)
Shin, Changsoo; Ha, Wansoo
2010-05-01
We present a review of full waveform inversion in the Laplace and Laplace-Fourier domains. Since Tarantola's pioneering work on waveform inversion, the practical application of full waveform inversions to real field data in the time or frequency domain has been nominal. The main hindrances in recovering a long-wavelength velocity model through full waveform inversion originate from a lack of low-frequency information in the data and the high non-linearity of the objective functions. The Laplace-domain wave equation can be obtained simply by changing the real frequencies from the Fourier transform into imaginary numbers. In terms of numerical integration, the Laplace-transformed wavefield is the sum of the damped wavefield from zero to infinity. Hence, Laplace-domain wavefields for each Laplace frequency can be treated as zero-frequency components of damped wavefields. The Laplace-transformed wavefield resembles a direct current field where only the source is used for Poisson's equation. The logarithmic objective function, combined with the Laplace transformed wavefield, has no local minima and a smoother convex form than conventional objective functions in the time or frequency domain. These characteristics of the Laplace domain wavefields and the objective function make Laplace domain inversions robust for real data, allowing us to start from scratch and recover smooth velocity models. Moreover, coarse grids, compared with time or frequency domain numerical modeling, can be used in the Laplace-domain inversion without sacrificing accuracy. The choice of Laplace frequencies to be used for inversion is roughly determined by inspecting a kernel of the Green's function for a horizontally two-layered media. Just as the zero-frequency component is exploited in a Laplace-domain inversion, a Laplace-Fourier domain inversion utilizes low, medium and high frequency information of damped wavefields. By introducing complex-valued frequencies in the Fourier transform and
The Laplace Planes of Uranus and Pluto
NASA Technical Reports Server (NTRS)
Dobrovolskis, Anthony R.
1993-01-01
Satellite orbits close to an oblate planet precess about its equatorial plane, while distant satellites precess around the plane of the planet's heliocentric orbit. In between, satellites in nearly circular orbits precess about a warped intermediate surface called the Laplace 'plane.' Herein we derive general formulas for locating the Laplace plane. Because Uranus and Pluto have high obliquities, their Laplace planes are severely warped. We present maps of these Laplace planes, of interest in telescopic searches for new satellites. The Laplace plane of the Solar System as a whole is similarly distorted, but comets in the inner Oort cloud precess too slowly to sense the Laplace plane.
SATELLITE DYNAMICS ON THE LAPLACE SURFACE
Tremaine, Scott; Touma, Jihad; Namouni, Fathi E-mail: jihad.touma@gmail.com
2009-03-15
The orbital dynamics of most planetary satellites is governed by the quadrupole moment from the equatorial bulge of the host planet and the tidal field from the Sun. On the Laplace surface, the long-term orbital evolution driven by the combined effects of these forces is zero, so that orbits have a fixed orientation and shape. The 'classical' Laplace surface is defined for circular orbits, and coincides with the planet's equator at small planetocentric distances and with its orbital plane at large distances. A dissipative circumplanetary disk should settle to this surface, and hence satellites formed from such a disk are likely to orbit in or near the classical Laplace surface. This paper studies the properties of Laplace surfaces. Our principal results are: (1) if the planetary obliquity exceeds 68.{sup 0}875, there is a range of semimajor axes in which the classical Laplace surface is unstable; (2) at some obliquities and planetocentric distances, there is a distinct Laplace surface consisting of nested eccentric orbits, which bifurcates from the classical Laplace surface at the point where instability sets in; (3) there is also a 'polar' Laplace surface perpendicular to the line of nodes of the planetary equator on the planetary orbit; (4) for circular orbits, the polar Laplace surface is stable at small planetocentric distances and unstable at large distances; (5) at the onset of instability, this polar Laplace surface bifurcates into two polar Laplace surfaces composed of nested eccentric orbits.
Waveform inversion in the shifted Laplace domain
NASA Astrophysics Data System (ADS)
Kwon, Jungmin; Jun, Hyunggu; Song, Hyeonjun; Jang, U. Geun; Shin, Changsoo
2017-07-01
Laplace domain waveform inversion (WI) is one of the most effective algorithms to generate an initial velocity model. Because of its bandwidth independence with respect to the source wavelet, this method can yield reasonable initial models without low-frequency components in the seismic data. However, the conventional Laplace domain WI algorithm has an accuracy problem from its simultaneous consideration of the first arrival traveltime and apparent amplitude in the Laplace domain wavefield. This simultaneous consideration creates undesirable cross-correlation terms between the residual of the traveltime and the partial derivatives of the apparent amplitude in the gradient directions and between the residual of the apparent amplitude and the partial derivatives of the traveltime in the gradient directions. In this paper, we introduce a new objective function that uses a shifted Laplace domain wavefield to solve the problem of Laplace domain WI. Information that is associated with the traveltime and apparent amplitude can be separately inverted by using this shifted Laplace domain WI. This separation of the information can suppress the undesirable cross-correlation terms between the residual of the traveltime and the partial derivatives of apparent amplitude and between the residual of the apparent amplitude and the partial derivatives of the traveltime in the gradient directions. We can effectively perform shifted Laplace domain modelling by using the damped monochromatic wave equation. We verify the accuracy of this shifted Laplace domain modelling scheme by comparing the shifted Laplace-transformed result from a synthetic seismogram to a wavefield that is modelled in the shifted Laplace domain. We perform a contribution analysis to demonstrate that the shifted Laplace domain wavefield is essential to improve the accuracy of the inverted results. Finally, we confirm the robustness of the shifted Laplace domain WI algorithm by testing it against a BP model.
Inversion and approximation of Laplace transforms
NASA Technical Reports Server (NTRS)
Lear, W. M.
1980-01-01
A method of inverting Laplace transforms by using a set of orthonormal functions is reported. As a byproduct of the inversion, approximation of complicated Laplace transforms by a transform with a series of simple poles along the left half plane real axis is shown. The inversion and approximation process is simple enough to be put on a programmable hand calculator.
Generalized Laplace Transforms and Extended Heaviside Calculus
ERIC Educational Resources Information Center
Deakin, Michael A. B.
2008-01-01
An extended Heaviside calculus proposed by Peraire in a recent paper is similar to a generalization of the Laplace transform proposed by the present author. This similarity will be illustrated by analysis of an example supplied by Peraire.
On computing Laplace's coefficients and their derivatives.
NASA Astrophysics Data System (ADS)
Gerasimov, I. A.; Vinnikov, E. L.
The algorithm of computing Laplace's coefficients and their derivatives is proposed with application of recurrent relations. The A.G.M.-method is used for the calculation of values L0(0), L0(1). The FORTRAN-program corresponding to the algorithm is given. The precision control was provided with numerical integrating by Simpsons method. The behavior of Laplace's coefficients and their third derivatives whith varying indices K, n for fixed values of the α-parameter is presented graphically.
Cummings, Eric; LaJeunesse, Tony
2008-10-05
Laplace is a electric field driven flow simulation program for detailed device design support. Transport processes include electrokinesis, dielectrophoresis, and diffusion. Laplace solves for the electric field in a microfluidic system and the liquid and particle flow that is produced by the electric field for the primary purpose of microfluidic design development and simulation. Laplace allows you to visualize the flow by tracking tracer particles, viewing flow streamlines, etc. Laplace can make movies of simulated particle motion to allow you to test and share the behavior of microfuidic designs. The electric field is calculated using an iterative linear solver and particle motion is solved by finite difference, finite-displacement simulation of particle trajectories. Laplace uses a bitmapped picture or drawing of a microsystem to infer the geometry. The channel depth is everywhere proportional to the magnitude of the blue channel of the image: 0 (black) = zero depth, or no channel, 256 (saturated blue) = deepest channel, and intermediate values correspond to intermediate depths. Laplace automatically applies various boundary conditions (applied voltage or current) to ports, where channels cross the edge of the image.
Parseval-Type Relations for Laplace Transform and their Applications
ERIC Educational Resources Information Center
Herman, S.; Maceli, J.; Rogala, M.; Yurekli, O.
2008-01-01
In the present note, two Parseval-type relations involving the Laplace transform are given. The application of the relations is demonstrated in evaluating improper integrals and Laplace transforms of trigonometric functions.
Evaluation of the Laplace Integral. Classroom Notes
ERIC Educational Resources Information Center
Chen, Hongwei
2004-01-01
Based on the dominated convergence theorem and parametric differentiation, two different evaluations of the Laplace integral are displayed. This article presents two different proofs of (1) which may be of interest since they are based on principles within the realm of real analysis. The first method applies the dominated convergence theorem to…
Laplace, Pierre-Simon (1749-1827)
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
Celestial mechanician, born in Beaumont-en-Auge, Normandy, France, became professor of mathematics at the Ecole Militaire in Paris, examining the cadet Napoleon Bonaparte. This position made Laplace well known to people in positions of power, which he opportunistically exploited, becoming, under Napoleon, Minister of the Interior (Napoleon soon removed him from office `because he brought the spir...
An approximation for inverse Laplace transforms
NASA Technical Reports Server (NTRS)
Lear, W. M.
1981-01-01
Programmable calculator runs simple finite-series approximation for Laplace transform inversions. Utilizing family of orthonormal functions, approximation is used for wide range of transforms, including those encountered in feedback control problems. Method works well as long as F(t) decays to zero as it approaches infinity and so is appliable to most physical systems.
Laplace's equation and Faraday's lines of force
Narasimhan, T.N.
2007-06-01
Boundary-value problems involve two dependent variables: a potential function, and a stream function. They can be approached in two mutually independent ways. The first, introduced by Laplace, involves spatial gradients at a point. Inspired by Faraday, Maxwell introduced the other, visualizing the flow domain as a collection of flow tubes and isopotential surfaces. Boundary-value problems intrinsically entail coupled treatment (or, equivalently, optimization) of potential and stream functions Historically, potential theory avoided the cumbersome optimization task through ingenious techniques such as conformal mapping and Green's functions. Laplace's point-based approach, and Maxwell's global approach, each provides its own unique insights into boundary-value problems. Commonly, Laplace's equation is solved either algebraically, or with approximate numerical methods. Maxwell's geometry-based approach opens up novel possibilities of direct optimization, providing an independent logical basis for numerical models, rather than treating them as approximate solvers of the differential equation. Whereas points, gradients, and Darcy's law are central to posing problems on the basis of Laplace's approach, flow tubes, potential differences, and the mathematical form of Ohm's law are central to posing them in natural coordinates oriented along flow paths. Besides being of philosophical interest, optimization algorithms can provide advantages that complement the power of classical numerical models. In the spirit of Maxwell, who eloquently spoke for a balance between abstract mathematical symbolism and observable attributes of concrete objects, this paper is an examination of the central ideas of the two approaches, and a reflection on how Maxwell's integral visualization may be practically put to use in a world of digital computers.
The PROSAIC Laplace and Fourier Transform
Smith, G.A.
1994-11-01
Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today`s emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting.
Feeling Wall Tension in an Interactive Demonstration of Laplace's Law
ERIC Educational Resources Information Center
Letic, Milorad
2012-01-01
Laplace's Law plays a major role in explanations of the wall tension of structures like blood vessels, the bladder, the uterus in pregnancy, bronchioles, eyeballs, and the behavior of aneurisms or the enlarged heart. The general relation of Laplace's law, expressing that the product of the radius of curvature (r) and pressure (P) is equal to wall…
Feeling Wall Tension in an Interactive Demonstration of Laplace's Law
ERIC Educational Resources Information Center
Letic, Milorad
2012-01-01
Laplace's Law plays a major role in explanations of the wall tension of structures like blood vessels, the bladder, the uterus in pregnancy, bronchioles, eyeballs, and the behavior of aneurisms or the enlarged heart. The general relation of Laplace's law, expressing that the product of the radius of curvature (r) and pressure (P) is equal to wall…
Towards Informetrics: Haitun, Laplace, Zipf, Bradford and the Alvey Programme.
ERIC Educational Resources Information Center
Brookes, B. C.
1984-01-01
Review of recent developments in statistical theories for social sciences highlights Haitun's statistical distributions, Laplace's "Law of Succession" and distribution, Laplace and Bradford analysis of book-index data, inefficiency of frequency distribution analysis, Laws of Bradford and Zipf, natural categorization, and Bradford Law and…
Laplace and the era of differential equations
NASA Astrophysics Data System (ADS)
Weinberger, Peter
2012-11-01
Between about 1790 and 1850 French mathematicians dominated not only mathematics, but also all other sciences. The belief that a particular physical phenomenon has to correspond to a single differential equation originates from the enormous influence Laplace and his contemporary compatriots had in all European learned circles. It will be shown that at the beginning of the nineteenth century Newton's "fluxionary calculus" finally gave way to a French-type notation of handling differential equations. A heated dispute in the Philosophical Magazine between Challis, Airy and Stokes, all three of them famous Cambridge professors of mathematics, then serves to illustrate the era of differential equations. A remark about Schrödinger and his equation for the hydrogen atom finally will lead back to present times.
Correlation Filtering of Modal Dynamics using the Laplace Wavelet
NASA Technical Reports Server (NTRS)
Freudinger, Lawrence C.; Lind, Rick; Brenner, Martin J.
1997-01-01
Wavelet analysis allows processing of transient response data commonly encountered in vibration health monitoring tasks such as aircraft flutter testing. The Laplace wavelet is formulated as an impulse response of a single mode system to be similar to data features commonly encountered in these health monitoring tasks. A correlation filtering approach is introduced using the Laplace wavelet to decompose a signal into impulse responses of single mode subsystems. Applications using responses from flutter testing of aeroelastic systems demonstrate modal parameters and stability estimates can be estimated by correlation filtering free decay data with a set of Laplace wavelets.
Population dynamics under the Laplace assumption.
Marreiros, André C; Kiebel, Stefan J; Daunizeau, Jean; Harrison, Lee M; Friston, Karl J
2009-02-01
In this paper, we describe a generic approach to modelling dynamics in neuronal populations. This approach models a full density on the states of neuronal populations but finesses this high-dimensional problem by re-formulating density dynamics in terms of ordinary differential equations on the sufficient statistics of the densities considered (c.f., the method of moments). The particular form for the population density we adopt is a Gaussian density (c.f., the Laplace assumption). This means population dynamics are described by equations governing the evolution of the population's mean and covariance. We derive these equations from the Fokker-Planck formalism and illustrate their application to a conductance-based model of neuronal exchanges. One interesting aspect of this formulation is that we can uncouple the mean and covariance to furnish a neural-mass model, which rests only on the populations mean. This enables us to compare equivalent mean-field and neural-mass models of the same populations and evaluate, quantitatively, the contribution of population variance to the expected dynamics. The mean-field model presented here will form the basis of a dynamic causal model of observed electromagnetic signals in future work.
Convergence rate of Cesaro means of Fourier-Laplace series
NASA Astrophysics Data System (ADS)
Li, Luoqing; Yu, Chunwu
2007-01-01
The convergence rate of Fourier-Laplace series in logarithmic subclasses of L2([Sigma]d) defined in terms of moduli of continuity is of interest. Lin and Wang [C. Lin, K. Wang, Convergence rate of Fourier-Laplace series of L2-functions, J. Approx. Theory 128 (2004) 103-114] recently presented a characterization of those subclasses and provided the almost everywhere convergence rates of Fourier-Laplace series in those subclasses. In this note, the almost everywhere convergence rates of the Cesaro means for Fourier-Laplace series of the logarithmic subclasses are obtained. The strong approximation order of the Cesaro means and the partial summation operators are also presented.
Use and Misuse of Laplace's Law in Ophthalmology
Chung, Cheuk Wang; Girard, Michaël J. A.; Jan, Ning-Jiun; Sigal, Ian A.
2016-01-01
Purpose Laplace's Law, with its compactness and simplicity, has long been employed in ophthalmology for describing the mechanics of the corneoscleral shell. We questioned the appropriateness of Laplace's Law for computing wall stress in the eye considering the advances in knowledge of ocular biomechanics. Methods In this manuscript we recapitulate the formulation of Laplace's Law, as well as common interpretations and uses in ophthalmology. Using numerical modeling, we study how Laplace's Law cannot account for important characteristics of the eye, such as variations in globe shape and size or tissue thickness, anisotropy, viscoelasticity, or that the eye is a living, dynamic organ. Results We show that accounting for various geometrical and material factors, excluded from Laplace's Law, can alter estimates of corneoscleral wall stress as much as 456% and, therefore, that Laplace's Law is unreliable. Conclusions We conclude by illustrating how computational techniques, such as finite element modeling, can account for the factors mentioned above, and are thus more suitable tools to provide quantitative characterization of corneoscleral biomechanics. PMID:26803799
An extension of the Laplace transform to Schwartz distributions
NASA Technical Reports Server (NTRS)
Price, D. R.
1974-01-01
A characterization of the Laplace transform is developed which extends the transform to the Schwartz distributions. The class of distributions includes the impulse functions and other singular functions which occur as solutions to ordinary and partial differential equations. The standard theorems on analyticity, uniqueness, and invertibility of the transform are proved by using the characterization as the definition of the Laplace transform. The definition uses sequences of linear transformations on the space of distributions which extends the Laplace transform to another class of generalized functions, the Mikusinski operators. It is shown that the sequential definition of the transform is equivalent to Schwartz' extension of the ordinary Laplace transform to distributions but, in contrast to Schwartz' definition, does not use the distributional Fourier transform. Several theorems concerning the particular linear transformations used to define the Laplace transforms are proved. All the results proved in one dimension are extended to the n-dimensional case, but proofs are presented only for those situations that require methods different from their one-dimensional analogs.
Conformal Laplace superintegrable systems in 2D: polynomial invariant subspaces
NASA Astrophysics Data System (ADS)
Escobar-Ruiz, M. A.; Miller, Willard, Jr.
2016-07-01
2nd-order conformal superintegrable systems in n dimensions are Laplace equations on a manifold with an added scalar potential and 2n-1 independent 2nd order conformal symmetry operators. They encode all the information about Helmholtz (eigenvalue) superintegrable systems in an efficient manner: there is a 1-1 correspondence between Laplace superintegrable systems and Stäckel equivalence classes of Helmholtz superintegrable systems. In this paper we focus on superintegrable systems in two-dimensions, n = 2, where there are 44 Helmholtz systems, corresponding to 12 Laplace systems. For each Laplace equation we determine the possible two-variate polynomial subspaces that are invariant under the action of the Laplace operator, thus leading to families of polynomial eigenfunctions. We also study the behavior of the polynomial invariant subspaces under a Stäckel transform. The principal new results are the details of the polynomial variables and the conditions on parameters of the potential corresponding to polynomial solutions. The hidden gl 3-algebraic structure is exhibited for the exact and quasi-exact systems. For physically meaningful solutions, the orthogonality properties and normalizability of the polynomials are presented as well. Finally, for all Helmholtz superintegrable solvable systems we give a unified construction of one-dimensional (1D) and two-dimensional (2D) quasi-exactly solvable potentials possessing polynomial solutions, and a construction of new 2D PT-symmetric potentials is established.
Laplace equation, magnetic recording and the Karlqvist approximation
NASA Astrophysics Data System (ADS)
Tannous, C.
2015-09-01
Magnetic recording head theory is based on the Karlqvist approximation to solve the Laplace equation over a polygonal domain that originates from a magnetostatic approach to describe the magnetic field produced by the read/write head in the recording medium. The approximation is reviewed and compared to various approaches dealing with solving the Laplace equation using different boundary conditions. The solution is obtained by the Green function, Fourier transform, Fourier series and finally by conformal mapping methods that allow us, on one hand, to comply with the Sommerfeld edge condition required at angular points and on the other, to obtain exact results.
Reconfigurable liquid metal circuits by Laplace pressure shaping
NASA Astrophysics Data System (ADS)
Cumby, Brad L.; Hayes, Gerard J.; Dickey, Michael D.; Justice, Ryan S.; Tabor, Christopher E.; Heikenfeld, Jason C.
2012-10-01
We report reconfigurable circuits formed by liquid metal shaping with <10 pounds per square inch (psi) Laplace and vacuum pressures. Laplace pressure drives liquid metals into microreplicated trenches, and upon release of vacuum, the liquid metal dewets into droplets that are compacted to 10-100× less area than when in the channel. Experimental validation includes measurements of actuation speeds exceeding 30 cm/s, simple erasable resistive networks, and switchable 4.5 GHz antennas. Such capability may be of value for next generation of simple electronic switches, tunable antennas, adaptive reflectors, and switchable metamaterials.
Nonlinearities distribution Laplace transform-homotopy perturbation method.
Filobello-Nino, Uriel; Vazquez-Leal, Hector; Benhammouda, Brahim; Hernandez-Martinez, Luis; Hoyos-Reyes, Claudio; Perez-Sesma, Jose Antonio Agustin; Jimenez-Fernandez, Victor Manuel; Pereyra-Diaz, Domitilo; Marin-Hernandez, Antonio; Diaz-Sanchez, Alejandro; Huerta-Chua, Jesus; Cervantes-Perez, Juan
2014-01-01
This article proposes non-linearities distribution Laplace transform-homotopy perturbation method (NDLT-HPM) to find approximate solutions for linear and nonlinear differential equations with finite boundary conditions. We will see that the method is particularly relevant in case of equations with nonhomogeneous non-polynomial terms. Comparing figures between approximate and exact solutions we show the effectiveness of the proposed method.
Discovering the Laplace Transform in Undergraduate Differential Equations
ERIC Educational Resources Information Center
Quinn, Terrance J.; Rai, Sanjay
2008-01-01
The Laplace Transform is an object of fundamental importance in pure and applied mathematics. In addition, it has special pedagogical value in that it can provide a natural and concrete setting for a student to begin thinking about the modern concepts of "operator" and "functional". Most undergraduate textbooks, however, merely define the…
Dynamical analysis of the Gliese-876 Laplace resonance
NASA Astrophysics Data System (ADS)
Martí, J. G.; Giuppone, C. A.; Beaugé, C.
2013-08-01
The number of multiple-planet systems known to be involved in mean motion conmensurabilities has increased significantly since the Kepler mission. Although most correspond to two-planet resonances, multiple resonances have also been found. The Laplace resonance is a particular case of a three-body resonance in which the period ratio between consecutive pairs is n1/n2 ˜ n2/n3 ˜ 2/1. It is not clear how this triple resonance acts to stabilize (or not) the system. The most reliable extrasolar system located in a Laplace resonance is GJ 876, because it has two independent confirmations. However, best-fit parameters were obtained without previous knowledge of resonance structure, and not all possible stable solutions for the system have been explored. In the present work we explore the various configurations allowed by the Laplace resonance in the GJ 876 system by varying the planetary parameters of the third outer planet. We find that in this case the Laplace resonance is a stabilization mechanism in itself, defined by a tiny island of regular motion surrounded by (unstable) highly chaotic orbits. Low-eccentricity orbits and mutual inclinations from -20° to 20° are compatible with observations. A definite range of mass ratio must be assumed to maintain orbital stability. Finally, we provide constraints on the argument of pericentres and mean anomalies to ensure stability for this kind of system.
Numerical Laplace Transform Inversion Employing the Gaver-Stehfest Algorithm.
ERIC Educational Resources Information Center
Jacquot, Raymond G.; And Others
1985-01-01
Presents a technique for the numerical inversion of Laplace Transforms and several examples employing this technique. Limitations of the method in terms of available computer word length and the effects of these limitations on approximate inverse functions are also discussed. (JN)
Laplace transform and the Mittag-Leffler function
NASA Astrophysics Data System (ADS)
Sales Teodoro, G.; Capelas de Oliveira, E.
2014-05-01
The exponential function is solution of a linear differential equation with constant coefficients, and the Mittag-Leffler function is solution of a fractional linear differential equation with constant coefficients. Using infinite series and Laplace transform, we introduce the Mittag-Leffler function as a generalization of the exponential function. Particular cases are recovered.
Discovering the Laplace Transform in Undergraduate Differential Equations
ERIC Educational Resources Information Center
Quinn, Terrance J.; Rai, Sanjay
2008-01-01
The Laplace Transform is an object of fundamental importance in pure and applied mathematics. In addition, it has special pedagogical value in that it can provide a natural and concrete setting for a student to begin thinking about the modern concepts of "operator" and "functional". Most undergraduate textbooks, however, merely define the…
Using Expected Value to Introduce the Laplace Transform
ERIC Educational Resources Information Center
Lutzer, Carl V.
2015-01-01
We propose an introduction to the Laplace transform in which Riemann sums are used to approximate the expected net change in a function, assuming that it quantifies a process that can terminate at random. We assume only a basic understanding of probability.
Using Expected Value to Introduce the Laplace Transform
ERIC Educational Resources Information Center
Lutzer, Carl V.
2015-01-01
We propose an introduction to the Laplace transform in which Riemann sums are used to approximate the expected net change in a function, assuming that it quantifies a process that can terminate at random. We assume only a basic understanding of probability.
Laplace-domain waveform inversion versus refraction-traveltime tomography
NASA Astrophysics Data System (ADS)
Bae, Ho Seuk; Pyun, Sukjoon; Shin, Changsoo; Marfurt, Kurt J.; Chung, Wookeen
2012-07-01
Geophysicists and applied mathematicians have proposed a rich suite of long-wavelength velocity estimation algorithms to construct starting velocity models for subsequent pre-stack depth migration and inversion. Refraction-traveltime tomography derives subsurface velocity models from picked first-arrival traveltimes. In contrast, Laplace-domain waveform inversion recovers long-wavelength velocity structure using the weighted amplitudes of first and later arrivals. There are several implementations of first-arrival traveltime inversion, with most based on ray tracing, and some based on the damped monochromatic wave equation, which accurately represent simple and finite-frequency first arrivals. Computationally, Laplace-domain wavefield inversion is quite similar to refraction-traveltime tomography using damped monochromatic wavefield, but the objective functions used in inversion are radically different. As in classical ray trace-based traveltime inversion, the objective of refraction-traveltime tomography using damped monochromatic wavefield is to match the phase (traveltime) of the first arrival of each measured seismic trace. In contrast, the objective of Laplace-domain wavefield inversion is to match the weighted amplitudes of both first and later arrivals to the weighted amplitudes of the measured seismic trace. Principles of refraction-traveltime tomography were used to generate velocity models of the earth one century ago. Laplace-domain waveform inversion is a more recently introduced algorithm and has been less rigorously studied by the seismic research community, with many workers believing it be equivalent to finite-frequency first-arrival traveltime tomography. We show that Laplace-domain waveform inversion is both theoretically and empirically different from finite-frequency first-arrival traveltime tomography. Specifically, we examine the Jacobian (sensitivity) kernels used in the two inversion schemes to quantify the different sensitivities (and hence
Graph Laplace for occluded face completion and recognition.
Deng, Yue; Dai, Qionghai; Zhang, Zengke
2011-08-01
This paper proposes a spectral-graph-based algorithm for face image repairing, which can improve the recognition performance on occluded faces. The face completion algorithm proposed in this paper includes three main procedures: 1) sparse representation for partially occluded face classification; 2) image-based data mining; and 3) graph Laplace (GL) for face image completion. The novel part of the proposed framework is GL, as named from graphical models and the Laplace equation, and can achieve a high-quality repairing of damaged or occluded faces. The relationship between the GL and the traditional Poisson equation is proven. We apply our face repairing algorithm to produce completed faces, and use face recognition to evaluate the performance of the algorithm. Experimental results verify the effectiveness of the GL method for occluded face completion.
Exponentials and Laplace transforms on nonuniform time scales
NASA Astrophysics Data System (ADS)
Ortigueira, Manuel D.; Torres, Delfim F. M.; Trujillo, Juan J.
2016-10-01
We formulate a coherent approach to signals and systems theory on time scales. The two derivatives from the time-scale calculus are used, i.e., nabla (forward) and delta (backward), and the corresponding eigenfunctions, the so-called nabla and delta exponentials, computed. With these exponentials, two generalised discrete-time Laplace transforms are deduced and their properties studied. These transforms are compatible with the standard Laplace and Z transforms. They are used to study discrete-time linear systems defined by difference equations. These equations mimic the usual continuous-time equations that are uniformly approximated when the sampling interval becomes small. Impulse response and transfer function notions are introduced. This implies a unified mathematical framework that allows us to approximate the classic continuous-time case when the sampling rate is high or to obtain the standard discrete-time case, based on difference equations, when the time grid becomes uniform.
Vector Helmholtz-Gauss and vector Laplace-Gauss beams.
Bandres, Miguel A; Gutiérrez-Vega, Julio C
2005-08-15
We demonstrate the existence of vector Helmholtz-Gauss (vHzG) and vector Laplace-Gauss beams that constitute two general families of localized vector beam solutions of the Maxwell equations in the paraxial approximation. The electromagnetic components are determined starting from the scalar solutions of the two-dimensional Helmholtz and Laplace equations, respectively. Special cases of the vHzG beams are TE and TM Gaussian vector beams, nondiffracting vector Bessel beams, polarized Bessel-Gauss beams, modes in cylindrical waveguides and cavities, and scalar Helmholtz-Gauss beams. The general expression of the vHzG beams can be used straightforwardly to obtain vector Mathieu-Gauss and vector parabolic-Gauss beams, which to our knowledge have not yet been reported.
Multipole Matrix of Green Function of Laplace Equation
NASA Astrophysics Data System (ADS)
Makuch, K.; Górka, P.
Multipole matrix elements of Green function of Laplace equation are calculated. The multipole matrix elements of Green function in electrostatics describe potential on a sphere which is produced by a charge distributed on the surface of a different (possibly overlapping) sphere of the same radius. The matrix elements are defined by double convolution of two spherical harmonics with the Green function of Laplace equation. The method we use relies on the fact that in the Fourier space the double convolution has simple form. Therefore we calculate the multipole matrix from its Fourier transform. An important part of our considerations is simplification of the three dimensional Fourier transformation of general multipole matrix by its rotational symmetry to the one-dimensional Hankel transformation.
The nonsinglet structure function evolution by Laplace method
Boroun, G. R. E-mail: boroun@razi.ac.ir; Zarrin, S.
2015-12-15
We derive a general scheme for the evolution of the nonsinglet structure function at the leadingorder (LO) and next-to-leading-order (NLO) by using the Laplace-transform technique. Results for the nonsinglet structure function are compared with MSTW2008, GRV, and CKMT parameterizations and also EMC experimental data in the LO and NLO analysis. The results are in good agreement with the experimental data and other parameterizations in the low- and large-x regions.
Four Poission-Laplace Theory of Gravitation (I)
NASA Astrophysics Data System (ADS)
Nyambuya, Golden Gadzirayi
2015-08-01
The Poisson-Laplace equation is a working and acceptable equation of gravitation which is mostly used or applied in its differential form in Magneto-Hydro-Dynamic (MHD) modelling of e.g. molecular clouds. From a general relativistic standpoint, it describes gravitational fields in the region of low spacetime curvature as it emerges in the weak field limit. For non-static gravitational fields, this equation is not generally covariant. On the requirements of general covariance, this equation can be extended to include a time-dependent component, in which case one is led to the Four Poisson-Laplace equation. We solve the Four Poisson-Laplace equation for radial solutions, and apart from the Newtonian gravitational component, we obtain four new solutions leading to four new gravitational components capable (in-principle) of explaining e.g. the Pioneer anomaly, the Titius-Bode Law and the formation of planetary rings. In this letter, we focus only on writing down these solutions. The task showing that these new solutions might explain the aforesaid gravitational anomalies has been left for separate future readings.
The Laplace resonance in the Kepler-60 planetary system
NASA Astrophysics Data System (ADS)
Goździewski, K.; Migaszewski, C.; Panichi, F.; Szuszkiewicz, E.
2016-01-01
We investigate the dynamical stability of the Kepler-60 planetary system with three super-Earths. We determine their orbital elements and masses by transit timing variation (TTV) data spanning quarters Q1-Q16 of the Kepler mission. The system is dynamically active but the TTV data constrain masses to ˜4 M⊕ and orbits in safely wide stable zones. The observations prefer two types of solutions. The true three-body Laplace mean-motion resonance (MMR) exhibits the critical angle librating around ≃45° and aligned apsides of the inner and outer pair of planets. In the Laplace MMR formed through a chain of two-planet 5:4 and 4:3 MMRs, all critical angles librate with small amplitudes ˜30° and apsidal lines in planet's pairs are anti-aligned. The system is simultaneously locked in a three-body MMR with librations amplitude ≃10o. The true Laplace MMR can evolve towards a chain of two-body MMRs in the presence of planetary migration. Therefore, the three-body MMR formed in this way seems to be more likely state of the system. However, the true three-body MMR cannot be disregarded a priori and it remains a puzzling configuration that may challenge the planet formation theory.
Newton, laplace, and the epistemology of systems biology.
Bittner, Michael L; Dougherty, Edward R
2012-01-01
For science, theoretical or applied, to significantly advance, researchers must use the most appropriate mathematical methods. A century and a half elapsed between Newton's development of the calculus and Laplace's development of celestial mechanics. One cannot imagine the latter without the former. Today, more than three-quarters of a century has elapsed since the birth of stochastic systems theory. This article provides a perspective on the utilization of systems theory as the proper vehicle for the development of systems biology and its application to complex regulatory diseases such as cancer.
Transfer Functions Via Laplace- And Fourier-Borel Transforms
NASA Technical Reports Server (NTRS)
Can, Sumer; Unal, Aynur
1991-01-01
Approach to solution of nonlinear ordinary differential equations involves transfer functions based on recently-introduced Laplace-Borel and Fourier-Borel transforms. Main theorem gives transform of response of nonlinear system as Cauchy product of transfer function and transform of input function of system, together with memory effects. Used to determine responses of electrical circuits containing variable inductances or resistances. Also possibility of doing all noncommutative algebra on computers in such symbolic programming languages as Macsyma, Reduce, PL1, or Lisp. Process of solution organized and possibly simplified by algebraic manipulations reducing integrals in solutions to known or tabulated forms.
Investigations of Tides from the Antiquity to Laplace
NASA Astrophysics Data System (ADS)
Deparis, Vincent; Legros, Hilaire; Souchay, Jean
Tidal phenomena along the coasts were known since the prehistoric era, but a long journey of investigations through the centuries was necessary from the Greco-Roman Antiquity to the modern era to unravel in a quasi-definitive way many secrets of the ebb and flow. These investigations occupied the great scholars from Aristotle to Galileo, Newton, Euler, d'Alembert, Laplace, and the list could go on. We will review the historical steps which contributed to an increasing understanding of the tides.
Enclosure method for the p-Laplace equation
NASA Astrophysics Data System (ADS)
Brander, Tommi; Kar, Manas; Salo, Mikko
2015-04-01
We study the enclosure method for the p-Calderón problem, which is a nonlinear generalization of the inverse conductivity problem due to Calderón that involves the p-Laplace equation. The method allows one to reconstruct the convex hull of an inclusion in the nonlinear model by using exponentially growing solutions introduced by Wolff. We justify this method for the penetrable obstacle case, where the inclusion is modelled as a jump in the conductivity. The result is based on a monotonicity inequality and the properties of the Wolff solutions.
NASA Astrophysics Data System (ADS)
Blacic, T. M.; Jun, H.; Shin, C.; Rosado, H.
2016-02-01
2-D temperature images of the ocean with resolution within a few tens of meters in distance and depth can be recovered from conventional marine multichannel seismic (MCS; low frequency acoustic) data via full waveform inversion (FWI), as demonstrated by several research groups in recent years. A primary limitation with FWI is that the more computationally efficient local inversion methods require an accurate estimate of the background sound speed in the material as a starting point to avoid converging to a local, rather than global, solution. In the ocean, expendable instruments are often used to obtain 1-D temperature and sound speed profiles; in typical MCS data collection, however, expendables are deployed just once per day, resulting in only one hydrographic profile every few hundred kilometers. In addition, the band-limited nature of seismic data, which typically lacks reliable frequencies below 5 Hz, makes it inherently challenging to extract the long wavelength sound speed directly from seismic data. Laplace domain inversion (LDI) developed by Changsoo Shin and colleagues requires only a simple starting model to produce smooth background sound speed models without requiring prior information about the medium. It works by transforming input data to the Laplace domain and then examining the zero frequency component of the damped wavefield to extract a smooth sound speed model. Laplace-Fourier domain inversion extends the technique to include additional frequencies below 5 Hz. This ability to use frequencies below those effectively propagated by the seismic source is what enables LDI to produce the smooth background trend from the data. We applied LDI to five synthetic data sets based on simplified models of oceanographic features and recovered smoothed versions of our synthetic models, demonstrating the viability of this method for creating sound speed profiles suitable for use as starting models for other FWI methods that produce more detailed models.
Experiments on active cloaking and illusion for Laplace equation.
Ma, Qian; Mei, Zhong Lei; Zhu, Shou Kui; Jin, Tian Yu; Cui, Tie Jun
2013-10-25
In recent years, invisibility cloaks have received a lot of attention and interest. These devices are generally classified into two types: passive and active. The design and realization of passive cloaks have been intensively studied using transformation optics and plasmonic approaches. However, active cloaks are still limited to theory and numerical simulations. Here, we present the first experiment on active cloaking and propose an active illusion for the Laplace equation. We make use of a resistor network to simulate a conducting medium. Then, we surround the central region with controlled sources to protect it from outside detection. We show that by dynamically changing the controlled sources, the protected region can be cloaked or disguised as different objects (illusion). Our measurement results agree very well with numerical simulations. Compared with the passive counterparts, the active cloaking and illusion devices do not need complicated metamaterials. They are flexible, in-line controllable, and adaptable to the environment. In addition to dc electricity, the proposed method can also be used for thermodynamics and other problems governed by the Laplace equation.
Modelling a single phase voltage controlled rectifier using Laplace transforms
NASA Technical Reports Server (NTRS)
Kraft, L. Alan; Kankam, M. David
1992-01-01
The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly.
Three-dimensional transient electromagnetic modeling in the Laplace Domain
Mizunaga, H.; Lee, Ki Ha; Kim, H.J.
1998-09-01
In modeling electromagnetic responses, Maxwell's equations in the frequency domain are popular and have been widely used (Nabighian, 1994; Newman and Alumbaugh, 1995; Smith, 1996, to list a few). Recently, electromagnetic modeling in the time domain using the finite difference (FDTD) method (Wang and Hohmann, 1993) has also been used to study transient electromagnetic interactions in the conductive medium. This paper presents a new technique to compute the electromagnetic response of three-dimensional (3-D) structures. The proposed new method is based on transforming Maxwell's equations to the Laplace domain. For each discrete Laplace variable, Maxwell's equations are discretized in 3-D using the staggered grid and the finite difference method (FDM). The resulting system of equations is then solved for the fields using the incomplete Cholesky conjugate gradient (ICCG) method. The new method is particularly effective in saving computer memory since all the operations are carried out in real numbers. For the same reason, the computing speed is faster than frequency domain modeling. The proposed approach can be an extremely useful tool in developing an inversion algorithm using the time domain data.
Experiments on Active Cloaking and Illusion for Laplace Equation
NASA Astrophysics Data System (ADS)
Ma, Qian; Mei, Zhong Lei; Zhu, Shou Kui; Jin, Tian Yu; Cui, Tie Jun
2013-10-01
In recent years, invisibility cloaks have received a lot of attention and interest. These devices are generally classified into two types: passive and active. The design and realization of passive cloaks have been intensively studied using transformation optics and plasmonic approaches. However, active cloaks are still limited to theory and numerical simulations. Here, we present the first experiment on active cloaking and propose an active illusion for the Laplace equation. We make use of a resistor network to simulate a conducting medium. Then, we surround the central region with controlled sources to protect it from outside detection. We show that by dynamically changing the controlled sources, the protected region can be cloaked or disguised as different objects (illusion). Our measurement results agree very well with numerical simulations. Compared with the passive counterparts, the active cloaking and illusion devices do not need complicated metamaterials. They are flexible, in-line controllable, and adaptable to the environment. In addition to dc electricity, the proposed method can also be used for thermodynamics and other problems governed by the Laplace equation.
The resurrection of Laplace's method of initial orbit determination
NASA Astrophysics Data System (ADS)
Taff, L. G.
1983-01-01
This report deals with a number of interrelated topics. The common thread is Laplace's method of initial orbit determination based on passively acquired optical data. We discuss this method's principal competitor (that of Gauss), the difficulties of Gauss's technique, and the traditional reasons the Gaussian method is preferred to the Laplacian. We reject this hegemony for a variety of reasons and concentrate on Laplace's method in an era of a surfeit of high quality data. This leads us into a discussion of data smoothing. Once one leaves the raw observatorial data the possibility of combining observations from multiple observers comes to mind and hence the determination of parallax by trigonometrical means. All of this may be applied to two different classes of objects-astroids and artificial satellites. Our immediate interests are in fast moving asteroids (greater than 0.5/day or an abnormally fast ecliptic latitude rate) and high altitude artificial satellites (P greater than 6h). In both instances it is the high inclination and high eccentricity subset which is of special concern.
Theories of comets to the age of Laplace
NASA Astrophysics Data System (ADS)
Heidarzadeh, Tofigh
Although the development of ideas about cometary motion has been investigated in several projects, a comprehensive and detailed survey of physical theories of comets has not been conducted. The available works either illustrate relatively short periods in the history of physical cometology or portray a landscape view without adequate details. The present study is an attempt to depict the details of the major physical theories of comets from Aristotle to the age of Laplace. The basic question from which this project originated was simple: how did natural philosophers and astronomers define the nature and place of a new category of celestial objects--the comets--after Brahe's estimation of cometary distances? However, a study starting merely from Brahe without covering classical and medieval thought about comets would be incomplete. Thus, based on the fundamental physical characteristics attributed to comets, the history of cometology may be divided into three periods: from Aristotle to Brahe, in which comets were assumed to be meteorological phenomena; from Brahe to Newton, when comets were admitted as celestial bodies but with unknown trajectories; and from Newton to Laplace, in which they were treated as members of the solar system having more or less the same properties of the planets. By estimating the mass of comets in the 1800s, Laplace diverted cometology into a different direction wherein they were considered among the smallest bodies in the solar system and deprived of the most important properties that had been used to explain their physical constitution during the previous two millennia. Ideas about the astrological aspects of comets are not considered in this study. Also, topics concerning the motion of comets are explained to the extent that is helpful in illustrating their physical properties. The main objective is to demonstrate the foundations of physical theories of comets, and the interaction between observational and mathematical astronomy, and
Laplace-Runge-Lenz vector for arbitrary spin
Nikitin, A. G.
2013-12-15
A countable set of superintegrable quantum mechanical systems is presented which admit the dynamical symmetry with respect to algebra so(4). This algebra is generated by the Laplace-Runge-Lenz vector generalized to the case of arbitrary spin. The presented systems describe neutral particles with non-trivial multipole momenta. Their spectra can be found algebraically like in the case of hydrogen atom. Solutions for the systems with spins 1/2 and 1 are presented explicitly, solutions for spin 3/2 can be expressed via solutions of an ordinary differential equation of first order. A more extended version of this paper including detailed calculations is published as an e-print arXiv:1308.4279.
MLPG approximation to the p-Laplace problem
NASA Astrophysics Data System (ADS)
Mirzaei, Davoud; Dehghan, Mehdi
2010-11-01
Meshless local Petrov-Galerkin (MLPG) method is discussed for solving 2D, nonlinear, elliptic p-Laplace or p-harmonic equation in this article. The problem is transferred to corresponding local boundary integral equation (LBIE) using Divergence theorem. The analyzed domain is divided into small circular sub-domains to which the LBIE is applied. To approximate the unknown physical quantities, nodal points spread over the analyzed domain and MLS approximation, are utilized. The method is a meshless method, since it does not require any background interpolation and integration cells and it dose not depend on geometry of domain. The proposed scheme is simple and computationally attractive. Applications are demonstrated through illustrative examples.
Caecal perforation from TB and the Law of Laplace
Khan, Amad N.; Khalid, Salema; Chaudhry, Mohammad Naushad; Ho, Cherrie
2015-01-01
A 43-year-old man presented to the hospital with haemoptysis. When worked up, his history and examination were highly suggestive of pulmonary tuberculosis (TB). He subsequently developed a massive upper gastrointestinal bleed and underwent an emergency laparotomy, which revealed a massively dilated caecum measuring ∼20 cm in diameter. The caecum had perforated due to acute decompensation of intestinal TB. Though common in developing countries, TB is rare in the UK, especially the intestinal kind. The most striking feature of this case is, however, the size of the caecal distension caused by the tubercular inflammation and subsequent perforation—something unheard of in the literature. This massive caecal distention would be explained by the Law of Laplace. In conclusion, massive distension and caecal perforation are possible consequences of intestinal TB, especially in the 48–72 h immediately after starting anti-tubercular therapy. PMID:25972412
Waveform Inversion of Synthetic Ocean Models in the Laplace Domain
NASA Astrophysics Data System (ADS)
Rosado, H.; Blacic, T. M.; Jun, H.; Shin, C.
2014-12-01
In seismic oceanography, the processed images show where small temperature changes (as little as 0.03°C) occur, although they do not give absolute temperatures. To get a 2-D temperature map, the data must be inverted for sound speed, which is then converted to temperature using equations of state. Full waveform inversion requires a starting model that is iteratively updated until the residuals converge. Global search algorithms such as Genetic Algorithm do not require a starting model close to the true model, but are computationally exhausting. Local search inversion is less expensive, but requires a reasonably accurate starting model. Unfortunately, most marine seismic data has little associated hydrographic data and so it is difficult to create starting models close enough to the true model for convergence throughout the target area. In addition, the band-limited nature of seismic data makes it inherently challenging to extract the long wavelength sound speed trend directly from seismic data. Laplace domain inversion (LDI) developed by Changsoo Shin and colleagues requires only a rudimentary starting model to produce smooth background sound speed models without requiring prior information about the medium. It works by transforming input data to the Laplace domain, and then examining the zero frequency component of the damped wavefield to extract a smooth sound speed model - basically, removing higher frequency fluctuations to expose background trends. This ability to use frequencies below those effectively propagated by the seismic source is what enables LDI to produce the smooth background trend from the data. We applied LDI to five synthetic data sets based on simplified models of oceanographic features. Using LDI, we were able to recover smoothed versions of our synthetic models, showing the viability of the method for creating sound speed profiles suitable for use as starting models for other methods of inversion that output more detailed models.
A fast Laplace solver approach to pore scale permeability
NASA Astrophysics Data System (ADS)
Arns, Christoph; Adler, Pierre
2017-04-01
The permeability of a porous medium can be derived by solving the Stokes equations in the pore space with no slip at the walls. The resulting velocity averaged over the pore volume yields the permeability KS by application of the Darcy law. The Stokes equations can be solved by a number of different techniques such as finite differences, finite volume, Lattice Boltzmann, but whatever the technique it remains a heavy task since there are four unknowns at each node (the three velocity components and the pressure) which necessitate the solution of four equations (the projection of Newton's law on each axis and mass conservation). By comparison, the Laplace equation is scalar with a single unknown at each node. The objective of this work is to replace the Stokes equations by an elliptical equation with a space dependent permeability. More precisely, the local permeability k is supposed to be proportional to (r-alpha)**2 where r is the distance of the voxel to the closest wall, and alpha a constant; k is zero in the solid phase. The elliptical equation is div(k gradp)=0. A macroscopic pressure gradient is assumed to be exerted on the medium and again the resulting velocity averaged over space yields a permeability K_L. In order to validate this method, systematic calculations have been performed. First, elementary shapes (plane channel, circular pipe, rectangular channels) were studied for which flow occurs along parallel lines in which case KL is the arithmetic average of the k's. KL was calculated for various discretizations of the pore space and various values of alpha. For alpha=0.5, the agreement with the exact analytical value of KS is excellent for the plane and rectangular channels while it is only approximate for circular pipes. Second, the permeability KL of channels with sinusoidal walls was calculated and compared with analytical results and numerical ones provided by a Lattice Boltzmann algorithm. Generally speaking, the discrepancy does not exceed 25% when
Nonparametric identification of structural modifications in Laplace domain
NASA Astrophysics Data System (ADS)
Suwała, G.; Jankowski, Ł.
2017-02-01
This paper proposes and experimentally verifies a Laplace-domain method for identification of structural modifications, which (1) unlike time-domain formulations, allows the identification to be focused on these parts of the frequency spectrum that have a high signal-to-noise ratio, and (2) unlike frequency-domain formulations, decreases the influence of numerical artifacts related to the particular choice of the FFT exponential window decay. In comparison to the time-domain approach proposed earlier, advantages of the proposed method are smaller computational cost and higher accuracy, which leads to reliable performance in more difficult identification cases. Analytical formulas for the first- and second-order sensitivity analysis are derived. The approach is based on a reduced nonparametric model, which has the form of a set of selected structural impulse responses. Such a model can be collected purely experimentally, which obviates the need for design and laborious updating of a parametric model, such as a finite element model. The approach is verified experimentally using a 26-node lab 3D truss structure and 30 identification cases of a single mass modification or two concurrent mass modifications.
Effectiveness of the Young-Laplace equation at nanoscale
Liu, Hailong; Cao, Guoxin
2016-01-01
Using molecular dynamics (MD) simulations, a new approach based on the behavior of pressurized water out of a nanopore (1.3–2.7 nm) in a flat plate is developed to calculate the relationship between the water surface curvature and the pressure difference across water surface. It is found that the water surface curvature is inversely proportional to the pressure difference across surface at nanoscale, and this relationship will be effective for different pore size, temperature, and even for electrolyte solutions. Based on the present results, we cannot only effectively determine the surface tension of water and the effects of temperature or electrolyte ions on the surface tension, but also show that the Young-Laplace (Y-L) equation is valid at nanoscale. In addition, the contact angle of water with the hydrophilic material can be further calculated by the relationship between the critical instable pressure of water surface (burst pressure) and nanopore size. Combining with the infiltration behavior of water into hydrophobic microchannels, the contact angle of water at nanoscale can be more accurately determined by measuring the critical pressure causing the instability of water surface, based on which the uncertainty of measuring the contact angle of water at nanoscale is highly reduced. PMID:27033874
Feynman formulas for semigroups generated by an iterated Laplace operator
NASA Astrophysics Data System (ADS)
Buzinov, M. S.
2017-04-01
In the present paper, we find representations of a one-parameter semigroup generated by a finite sum of iterated Laplace operators and an additive perturbation (the potential). Such semigroups and the evolution equations corresponding to them find applications in the field of physics, chemistry, biology, and pattern recognition. The representations mentioned above are obtained in the form of Feynman formulas, i.e., in the form of a limit of multiple integrals as the multiplicity tends to infinity. The term "Feynman formula" was proposed by Smolyanov. Smolyanov's approach uses Chernoff's theorems. A simple form of representations thus obtained enables one to use them for numerical modeling the dynamics of the evolution system as a method for the approximation of solutions of equations. The problems considered in this note can be treated using the approach suggested by Remizov (see also the monograph of Smolyanov and Shavgulidze on path integrals). The representations (of semigroups) obtained in this way are more complicated than those given by the Feynman formulas; however, it is possible to bypass some analytical difficulties.
Wavelet-based denoising using local Laplace prior
NASA Astrophysics Data System (ADS)
Rabbani, Hossein; Vafadust, Mansur; Selesnick, Ivan
2007-09-01
Although wavelet-based image denoising is a powerful tool for image processing applications, relatively few publications have addressed so far wavelet-based video denoising. The main reason is that the standard 3-D data transforms do not provide useful representations with good energy compaction property, for most video data. For example, the multi-dimensional standard separable discrete wavelet transform (M-D DWT) mixes orientations and motions in its subbands, and produces the checkerboard artifacts. So, instead of M-D DWT, usually oriented transforms suchas multi-dimensional complex wavelet transform (M-D DCWT) are proposed for video processing. In this paper we use a Laplace distribution with local variance to model the statistical properties of noise-free wavelet coefficients. This distribution is able to simultaneously model the heavy-tailed and intrascale dependency properties of wavelets. Using this model, simple shrinkage functions are obtained employing maximum a posteriori (MAP) and minimum mean squared error (MMSE) estimators. These shrinkage functions are proposed for video denoising in DCWT domain. The simulation results shows that this simple denoising method has impressive performance visually and quantitatively.
4. Historic American Buildings Survey Drawing by LaPlace VIEW FROM ...
4. Historic American Buildings Survey Drawing by LaPlace VIEW FROM HILL TO REAR OF MISSION GROUNDS - 1839 - Mission San Carlos Borromeo, Rio Road & Lausen Drive, Carmel-by-the-Sea, Monterey County, CA
Extremal metrics for eigenvalues of the Laplace-Beltrami operator on surfaces
NASA Astrophysics Data System (ADS)
Penskoi, A. V.
2013-12-01
Known results on geometric optimisation of eigenvalues of the Laplace operator are briefly reviewed, and a more detailed survey of recent results in the theory of extremal metrics on surfaces is presented. Bibliography: 78 titles.
NASA Technical Reports Server (NTRS)
Truong, K. V.; Unal, Aynur; Tobak, M.
1989-01-01
Various features of the solutions of Duffing's equation are described using a representation of the solutions in the Laplace-Borel transform domain. An application of this technique is illustrated for the symmetry-breaking bifurcation of a hard spring.
Real Variable Inversion of Laplace Transforms: An Application in Plasma Physics.
ERIC Educational Resources Information Center
Bohn, C. L.; Flynn, R. W.
1978-01-01
Discusses the nature of Laplace transform techniques and explains an alternative to them: the Widder's real inversion. To illustrate the power of this new technique, it is applied to a difficult inversion: the problem of Landau damping. (GA)
Laplace homotopy perturbation method for Burgers equation with space- and time-fractional order
NASA Astrophysics Data System (ADS)
Johnston, S. J.; Jafari, H.; Moshokoa, S. P.; Ariyan, V. M.; Baleanu, D.
2016-01-01
The fractional Burgers equation describes the physical processes of unidirectional propagation of weakly nonlinear acoustic waves through a gas-filled pipe. The Laplace homotopy perturbation method is discussed to obtain the approximate analytical solution of space-fractional and time-fractional Burgers equations. The method used combines the Laplace transform and the homotopy perturbation method. Numerical results show that the approach is easy to implement and accurate when applied to partial differential equations of fractional orders.
Relaxation spectroscopy of deep levels in semiconductors: Laplace-DLTS method
NASA Astrophysics Data System (ADS)
Levin, M. N.; Bormontov, A. E.; Akhkubekov, A. É.; Tatokhin, E. A.
2010-11-01
Deep level transient spectroscopy (DLTS) is among the main methods used to determine the parameters of electrically active centers of charge localization in semiconductors. In order to increase the accuracy and adequacy of DLTS data, we propose a modified approach based on the application of an inverse Laplace transform. Using the proposed Laplace-DLTS method, it is possible to determine the parameters of centers with close carrier emission coefficients, which cannot be done using the traditional DLTS technique.
NASA Technical Reports Server (NTRS)
Friedrich, R.; Drewelow, W.
1978-01-01
An algorithm is described that is based on the method of breaking the Laplace transform down into partial fractions which are then inverse-transformed separately. The sum of the resulting partial functions is the wanted time function. Any problems caused by equation system forms are largely limited by appropriate normalization using an auxiliary parameter. The practical limits of program application are reached when the degree of the denominator of the Laplace transform is seven to eight.
Some practical observations on the predictor jump method for solving the Laplace equation
NASA Astrophysics Data System (ADS)
Duque-Carrillo, J. F.; Vega-Fernández, J. M.; Peña-Bernal, J. J.; Rossell-Bueno, M. A.
1986-01-01
The best conditions for the application of the predictor jump (PJ) method in the solution of the Laplace equation are discussed and some practical considerations for applying this new iterative technique are presented. The PJ method was remarked on in a previous article entitled ``A new way for solving Laplace's problem (the predictor jump method)'' [J. M. Vega-Fernández, J. F. Duque-Carrillo, and J. J. Peña-Bernal, J. Math. Phys. 26, 416 (1985)].
Cheng, Tian-Le; Wang, Yu U
2013-07-15
The self-assembly behavior of shape-anisotropic particles at curved fluid interfaces is computationally investigated by diffuse interface field approach (DIFA). A Gibbs-Duhem-type thermodynamic formalism is introduced to treat heterogeneous pressure within the phenomenological model, in agreement with Young-Laplace equation. Computer simulations are performed to study the effects of capillary forces (interfacial tension and Laplace pressure) on particle self-assembly at fluid interfaces in various two-dimensional cases. For isolated particles, it is found that the equilibrium liquid interface remains circular and particles of different shapes do not disturb the homogeneous curvature of liquid interface, while the equilibrium position, orientation and stability of a particle at the liquid interface depend on its shape and initial location with respect to the liquid interface. For interacting particles, the curvature of local liquid interfaces is different from the apparent curvature of the particle shell; nevertheless, irrespective of the particle shapes, a particle-coated droplet always tends to deform into a circular morphology under positive Laplace pressure, loses mechanical stability and collapses under negative Laplace pressure, while adapts to any morphology and stays in neutral equilibrium under zero Laplace pressure. Finally, the collective behaviors of particles and Laplace pressure evolution in bicontinuous interfacially jammed emulsion gels (bijels) are investigated. Copyright © 2013 Elsevier Inc. All rights reserved.
Investigation of Laplace barriers for arrayed electrowetting lab-on-a-chip.
Schultz, A; Papautsky, I; Heikenfeld, J
2014-05-13
Partial-post Laplace barriers have been postulated as a means to allow electrowetting transport and geometrical reshaping of fluids, followed by the preservation of fluid geometry after the electrowetting voltage is removed. Reported here is the first investigation of Laplace barriers with the arrayed electrodes and splitting/merging transport functions for an electrowetting lab-on-a-chip. Laplace barriers optimized for 500 × 500 μm(2) electrodes and 78 μm channel height are shown to provide geometrical control of fluid shape down to radii of curvature of ~70 μm. The Laplace barriers increase the splitting volume error, but with proper electrical control, the average error in the split volume is reduced to 5%. Improved programmable fluid storage in droplets or reservoirs and continuous channel flow are also shown. This work confirms the potential benefits of Laplace barriers for lab-on-a-chip and also reveals the unique challenges and operation requirements for Laplace barriers in lab-on-a-chip applications.
Laplace plane modifications arising from solar radiation pressure
Rosengren, Aaron J.; Scheeres, Daniel J.
2014-05-01
The dynamical effects of solar radiation pressure (SRP) in the solar system have been rigorously studied since the early 1900s. This non-gravitational perturbation plays a significant role in the evolution of dust particles in circumplanetary orbits, as well as in the orbital motion about asteroids and comets. For gravitationally dominated orbits, SRP is negligible and the resulting motion is largely governed by the oblateness of the primary and the attraction of the Sun. The interplay between these gravitational perturbations gives rise to three mutually perpendicular planes of equilibrium for circular satellite orbits. The classical Laplace plane lies between the equatorial and orbital planes of the primary, and is the mean reference plane about whose axis the pole of a satellite's orbit precesses. From a previously derived solution for the secular motion of an orbiter about a small body in a SRP dominated environment, we find that SRP acting alone will cause an initially circular orbit to precess around the pole of the primary's heliocentric orbital plane. When the gravitational and non-gravitational perturbations act in concert, the resulting equilibrium planes turn out to be qualitatively different, in some cases, from those obtained without considering the radiation pressure. The warping of the surfaces swept out by the modified equilibria as the semi-major axis varies depends critically on the cross-sectional area of the body exposed. These results, together with an adiabatic invariance argument on Poynting-Robertson drag, provide a natural qualitative explanation for the initial albedo dichotomy of Saturn's moon, Iapetus.
Fast Solvers for Transient Hydraulic Tomography based on Laplace transform
NASA Astrophysics Data System (ADS)
Bakhos, T.; Saibaba, A.; Kitanidis, P. K.
2013-12-01
Transient Hydraulic Tomography (THT) is a method to estimate the parameters hydraulic conductivity and specific storage, from measurements of hydraulic heads or pressure obtained in a series of interference tests in aquifer geologic formation such as an aquifer (i.e., pumping at one location and depth while measuring the response at several others). These measurements can be used to reconstruct the spatial variation of hydraulic parameters by solving a nonlinear inverse problem, which we tackle using the geostatistical approach. A central challenge associated with the application of the geostatistical approach to THT, is the computational cost associated with constructing the Jacobian - which represents the sensitivity of the measurements to the unknown parameters. This essentially requires repeated solutions to the 'forward problem' and the 'adjoint problem' for determination of derivatives, which are both time-dependent parabolic partial differential equations. To solve the 'forward problem', we use a Laplace Transform based exponential time integrator combined with a Krylov subspace based method for solving shifted systems. This approach allows us to independently evaluate the transient problem at different time instants at (almost) the cost of solving one steady-state groundwater equation. A similar approach can be used to accelerate the solution of the 'adjoint problem' as well. As we demonstrate, this approach dramatically lowers the computational cost associated with evaluating the Jacobian and as a result, the reconstruction of the parameters. The performance of our algorithm is demonstrated on some challenging synthetic examples; in particular, we apply it to large-scale inverse problems arising from transient hydraulic tomography.
Julià, Olga; Vidal-Mas, Jaume; Panikov, Nicolai S.; Vives-Rego, Josep
2010-01-01
We report a skew-Laplace statistical analysis of both flow cytometry scatters and cell size from microbial strains primarily grown in batch cultures, others in chemostat cultures and bacterial aquatic populations. Cytometry scatters best fit the skew-Laplace distribution while cell size as assessed by an electronic particle analyzer exhibited a moderate fitting. Unlike the cultures, the aquatic bacterial communities clearly do not fit to a skew-Laplace distribution. Due to its versatile nature, the skew-Laplace distribution approach offers an easy, efficient, and powerful tool for distribution of frequency analysis in tandem with the flow cytometric cell sorting. PMID:20592754
Julià, Olga; Vidal-Mas, Jaume; Panikov, Nicolai S; Vives-Rego, Josep
2010-01-01
We report a skew-Laplace statistical analysis of both flow cytometry scatters and cell size from microbial strains primarily grown in batch cultures, others in chemostat cultures and bacterial aquatic populations. Cytometry scatters best fit the skew-Laplace distribution while cell size as assessed by an electronic particle analyzer exhibited a moderate fitting. Unlike the cultures, the aquatic bacterial communities clearly do not fit to a skew-Laplace distribution. Due to its versatile nature, the skew-Laplace distribution approach offers an easy, efficient, and powerful tool for distribution of frequency analysis in tandem with the flow cytometric cell sorting.
Well test analysis benefits from new method of Laplace space inversion
Wooden, B.; Azari, M.; Soliman, M. )
1992-07-20
This paper reports that for modeling well test data more reliably, a new computer program easily and accurately inverts the Laplace transform. Converting real time and space solution to Laplace space is often done in the petroleum industry and provides the vehicle to develop numerous new solutions. The Laplace space transform is frequently used in pressure transient analysis primarily because it can reduce or transform a highly difficult problem into a much simpler one. Typically, a Laplace space equation can be manipulated by use of simple algebra to accomplish other desired ends, such as incorporating additional transformed equations to solve other aspects of the engineering problem. Once the transformed equation is complete, it is then necessary to convert to real time and space. This conversion is accomplished analytically by what is referred to as inverting the Laplace transform with sets of formulas and relationships between real and transformed space and time. In many cases, this inversion is not easy or cannot be done by conventional analytic means. In those situation, an engineer requires a program that numerically inverts the transform. The new program, the Azari-Wooden-Graver, or AWG method, has this capability.
Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis
NASA Astrophysics Data System (ADS)
Ahola, Susanna; Zhivonitko, Vladimir V.; Mankinen, Otto; Zhang, Guannan; Kantola, Anu M.; Chen, Hsueh-Ying; Hilty, Christian; Koptyug, Igor V.; Telkki, Ville-Veikko
2015-09-01
Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhancing the resolution and information content of corresponding 1D experiments as well as reducing the experiment time by one to two orders of magnitude or more as compared with its conventional 2D counterpart. We demonstrate that the method allows one to distinguish identical molecules in different physical environments and provides chemical resolution missing in NMR spectra. Although the sensitivity of the new method is reduced due to spatial encoding, the single-scan approach enables one to use hyperpolarized substances to boost the sensitivity by several orders of magnitude, significantly enhancing the overall sensitivity of multidimensional Laplace NMR.
NASA Astrophysics Data System (ADS)
Majić, Matt R. A.; Auguié, Baptiste; Le Ru, Eric C.
2017-03-01
We propose a powerful approach to solve Laplace's equation for point sources near a spherical object. The central new idea is to use prolate spheroidal solid harmonics, which are separable solutions of Laplace's equation in spheroidal coordinates, instead of the more natural spherical solid harmonics. Using electrostatics as an example, we motivate this choice and show that the resulting series expansions converge much faster. This improvement is discussed in terms of the singularity of the solution and its analytic continuation. The benefits of this approach are further illustrated for a specific example: the calculation of modified decay rates of light emitters close to nanostructures in the quasistatic approximation. We expect the general approach to be applicable with similar benefits to the solution of Laplace's equation for other geometries and to other equations of mathematical physics.
Fundamental improvements of the piecewise semi-smooth Laplace-Beltrami operator numerical stability
NASA Astrophysics Data System (ADS)
Pecha, Marek; Jirutkova, Pavla; Cermak, Martin
2017-07-01
The Laplace-Beltrami operator plays an important role as C2 function smoother and its eigenfunction applications are studied extensively in last five decades, not only, in image processing field but we can meet with these functions ranging from molecular physics scientific field to mechanical engineering. However, in many non-trivial cases, e.g. computations on non-uniform meshes, the discrete Laplace operator could be ill-conditioned and inappropriate for numerical computations. Especially, in the spectral clustering tool, a condition number of the graph Laplacian goes to infinity, when pairwise similarities among most graph nodes go to zero. Therefore, in this paper, we reformulate the image graph Laplacian as the semi-smooth Laplace-Beltrami operator on a non-uniform mesh and study its numerical properties, then we introduce our fundamental approach for improving a numerical stability of this operator.
Regularized Laplace-Fourier-Domain Full Waveform Inversion Using a Weighted l 2 Objective Function
NASA Astrophysics Data System (ADS)
Jun, Hyunggu; Kwon, Jungmin; Shin, Changsoo; Zhou, Hongbo; Cogan, Mike
2017-03-01
Full waveform inversion (FWI) can be applied to obtain an accurate velocity model that contains important geophysical and geological information. FWI suffers from the local minimum problem when the starting model is not sufficiently close to the true model. Therefore, an accurate macroscale velocity model is essential for successful FWI, and Laplace-Fourier-domain FWI is appropriate for obtaining such a velocity model. However, conventional Laplace-Fourier-domain FWI remains an ill-posed and ill-conditioned problem, meaning that small errors in the data can result in large differences in the inverted model. This approach also suffers from certain limitations related to the logarithmic objective function. To overcome the limitations of conventional Laplace-Fourier-domain FWI, we introduce a weighted l 2 objective function, instead of the logarithmic objective function, as the data-domain objective function, and we also introduce two different model-domain regularizations: first-order Tikhonov regularization and prior model regularization. The weighting matrix for the data-domain objective function is constructed to suitably enhance the far-offset information. Tikhonov regularization smoothes the gradient, and prior model regularization allows reliable prior information to be taken into account. Two hyperparameters are obtained through trial and error and used to control the trade-off and achieve an appropriate balance between the data-domain and model-domain gradients. The application of the proposed regularizations facilitates finding a unique solution via FWI, and the weighted l 2 objective function ensures a more reasonable residual, thereby improving the stability of the gradient calculation. Numerical tests performed using the Marmousi synthetic dataset show that the use of the weighted l 2 objective function and the model-domain regularizations significantly improves the Laplace-Fourier-domain FWI. Because the Laplace-Fourier-domain FWI is improved, the
Tidal Friction in the Earth-Moon System and Laplace Planes: Darwin Redux
NASA Technical Reports Server (NTRS)
Rubincam, David P.
2015-01-01
The dynamical evolution of the Earth-Moon system due to tidal friction is treated here. George H. Darwin used Laplace planes (also called proper planes) in his study of tidal evolution. The Laplace plane approach is adapted here to the formalisms of W.M. Kaula and P. Goldreich. Like Darwin, the approach assumes a three-body problem: Earth, Moon, and Sun, where the Moon and Sun are point-masses. The tidal potential is written in terms of the Laplace plane angles. The resulting secular equations of motion can be easily integrated numerically assuming the Moon is in a circular orbit about the Earth and the Earth is in a circular orbit about the Sun. For Earth-Moon distances greater than 10 Earth radii, the Earth's approximate tidal response can be characterized with a single parameter, which is a ratio: a Love number times the sine of a lag angle divided by another such product. For low parameter values it can be shown that Darwin's low-viscosity molten Earth, M. Ross's and G. Schubert's model of an Earth near melting, and Goldreich's equal tidal lag angles must all give similar histories. For higher parameter values, as perhaps has been the case at times with the ocean tides, the Earth's obliquity may have decreased slightly instead of increased once the Moon's orbit evolved further than 50 Earth radii from the Earth, with possible implications for climate. This is contrast to the other tidal friction models mentioned, which have the obliquity always increasing with time. As for the Moon, its orbit is presently tilted to its Laplace plane by 5.2deg. The equations do not allow the Moon to evolve out of its Laplace plane by tidal friction alone, so that if it was originally in its Laplace plane, the tilt arose with the addition of other mechanisms, such as resonance passages.
Regularized Laplace-Fourier-Domain Full Waveform Inversion Using a Weighted l 2 Objective Function
NASA Astrophysics Data System (ADS)
Jun, Hyunggu; Kwon, Jungmin; Shin, Changsoo; Zhou, Hongbo; Cogan, Mike
2016-09-01
Full waveform inversion (FWI) can be applied to obtain an accurate velocity model that contains important geophysical and geological information. FWI suffers from the local minimum problem when the starting model is not sufficiently close to the true model. Therefore, an accurate macroscale velocity model is essential for successful FWI, and Laplace-Fourier-domain FWI is appropriate for obtaining such a velocity model. However, conventional Laplace-Fourier-domain FWI remains an ill-posed and ill-conditioned problem, meaning that small errors in the data can result in large differences in the inverted model. This approach also suffers from certain limitations related to the logarithmic objective function. To overcome the limitations of conventional Laplace-Fourier-domain FWI, we introduce a weighted l 2 objective function, instead of the logarithmic objective function, as the data-domain objective function, and we also introduce two different model-domain regularizations: first-order Tikhonov regularization and prior model regularization. The weighting matrix for the data-domain objective function is constructed to suitably enhance the far-offset information. Tikhonov regularization smoothes the gradient, and prior model regularization allows reliable prior information to be taken into account. Two hyperparameters are obtained through trial and error and used to control the trade-off and achieve an appropriate balance between the data-domain and model-domain gradients. The application of the proposed regularizations facilitates finding a unique solution via FWI, and the weighted l 2 objective function ensures a more reasonable residual, thereby improving the stability of the gradient calculation. Numerical tests performed using the Marmousi synthetic dataset show that the use of the weighted l 2 objective function and the model-domain regularizations significantly improves the Laplace-Fourier-domain FWI. Because the Laplace-Fourier-domain FWI is improved, the
Tidal friction in the Earth-Moon system and Laplace planes: Darwin redux
NASA Astrophysics Data System (ADS)
Rubincam, David Parry
2016-03-01
The dynamical evolution of the Earth-Moon system due to tidal friction is treated here. George H. Darwin used Laplace planes (also called proper planes) in his study of tidal evolution. The Laplace plane approach is adapted here to the formalisms of W.M. Kaula and P. Goldreich. Like Darwin, the approach assumes a three-body problem: Earth, Moon, and Sun, where the Moon and Sun are point-masses. The tidal potential is written in terms of the Laplace plane angles. The resulting secular equations of motion can be easily integrated numerically assuming the Moon is in a circular orbit about the Earth and the Earth is in a circular orbit about the Sun. For Earth-Moon distances greater than ∼10 Earth radii, the Earth's approximate tidal response can be characterized with a single parameter, which is a ratio: a Love number times the sine of a lag angle divided by another such product. For low parameter values it can be shown that Darwin's low-viscosity molten Earth, M. Ross's and G. Schubert's model of an Earth near melting, and Goldreich's equal tidal lag angles must all give similar histories. For higher parameter values, as perhaps has been the case at times with the ocean tides, the Earth's obliquity may have decreased slightly instead of increased once the Moon's orbit evolved further than 50 Earth radii from the Earth, with possible implications for climate. This is contrast to the other tidal friction models mentioned, which have the obliquity always increasing with time. As for the Moon, its orbit is presently tilted to its Laplace plane by 5.2°. The equations do not allow the Moon to evolve out of its Laplace plane by tidal friction alone, so that if it was originally in its Laplace plane, the tilt arose with the addition of other mechanisms, such as resonance passages.
Convergent radial dispersion: a note on evaluation of the Laplace transform solution
Moench, A.F.
1991-01-01
A numerical inversion algorithm for Laplace transforms that is capable of handling rapid changes in the computed function is applied to the Laplace transform solution to the problem of convergent radial dispersion in a homogeneous aquifer. Prior attempts by the author to invert this solution were unsuccessful for highly advective systems where the Peclet number was relatively large. The algorithm used in this note allows for rapid and accurate inversion of the solution for all Peclet numbers of practical interest, and beyond. Dimensionless breakthrough curves are illustrated for tracer input in the form of a step function, a Dirac impulse, or a rectangular input. -Author
USDA-ARS?s Scientific Manuscript database
The Kyoto Protocol is an agreement among many of the world’s nations to, among other things, reduce atmospheric carbon dioxide concentrations in order to reduce global warming. One potential method to do so is to sequester carbon in soils. This has had the effect of stimulating the establishment of ...
NASA Astrophysics Data System (ADS)
Fadly Nurullah Rasedee, Ahmad; Ahmedov, Anvarjon; Sathar, Mohammad Hasan Abdul
2017-09-01
The mathematical models of the heat and mass transfer processes on the ball type solids can be solved using the theory of convergence of Fourier-Laplace series on unit sphere. Many interesting models have divergent Fourier-Laplace series, which can be made convergent by introducing Riesz and Cesaro means of the series. Partial sums of the Fourier-Laplace series summed by Riesz method are integral operators with the kernel known as Riesz means of the spectral function. In order to obtain the convergence results for the partial sums by Riesz means we need to know an asymptotic behavior of the latter kernel. In this work the estimations for Riesz means of spectral function of Laplace-Beltrami operator which guarantees the convergence of the Fourier-Laplace series by Riesz method are obtained.
Some Half-Row Sums from Pascal's Triangle via Laplace Transforms
ERIC Educational Resources Information Center
Dence, Thomas P.
2007-01-01
This article presents some identities on the sum of the entries in the first half of a row in Pascal's triangle. The results were discovered while the author was working on a problem involving Laplace transforms, which are used in proving of the identities.
New modification of Laplace decomposition method for seventh order KdV equation
NASA Astrophysics Data System (ADS)
Kashkari, B. S.; Bakodah, H. O.
2013-10-01
In this paper, we develop a new modification of Laplace decomposition method for solving the seventh order KdV equations. The numerical results show that the method converges rapidly and compared with the Adomian decomposition method. The conservation properties of solution are examined by calculating the first three invariants.
Extensivity of Rényi entropy for the Laplace-de Finetti distribution
NASA Astrophysics Data System (ADS)
Bergeron, H.; Curado, E. M. F.; Gazeau, J. P.; Rodrigues, Ligia M. C. S.
2016-01-01
The Boltzmann-Gibbs entropy is known to be asymptotically extensive for the Laplace-de Finetti distribution. We prove here that the same result holds in the case of the Rényi entropy. We also show some interesting lower and upper bounds for the asymptotic limit of these entropies.
Reuter, Martin; Wolter, Franz-Erich; Shenton, Martha; Niethammer, Marc
2009-01-01
This paper proposes the use of the surface based Laplace-Beltrami and the volumetric Laplace eigenvalues and -functions as shape descriptors for the comparison and analysis of shapes. These spectral measures are isometry invariant and therefore allow for shape comparisons with minimal shape pre-processing. In particular, no registration, mapping, or remeshing is necessary. The discriminatory power of the 2D surface and 3D solid methods is demonstrated on a population of female caudate nuclei (a subcortical gray matter structure of the brain, involved in memory function, emotion processing, and learning) of normal control subjects and of subjects with schizotypal personality disorder. The behavior and properties of the Laplace-Beltrami eigenvalues and -functions are discussed extensively for both the Dirichlet and Neumann boundary condition showing advantages of the Neumann vs. the Dirichlet spectra in 3D. Furthermore, topological analyses employing the Morse-Smale complex (on the surfaces) and the Reeb graph (in the solids) are performed on selected eigenfunctions, yielding shape descriptors, that are capable of localizing geometric properties and detecting shape differences by indirectly registering topological features such as critical points, level sets and integral lines of the gradient field across subjects. The use of these topological features of the Laplace-Beltrami eigenfunctions in 2D and 3D for statistical shape analysis is novel. PMID:20161035
Reuter, Martin; Wolter, Franz-Erich; Shenton, Martha; Niethammer, Marc
2009-10-01
This paper proposes the use of the surface based Laplace-Beltrami and the volumetric Laplace eigenvalues and -functions as shape descriptors for the comparison and analysis of shapes. These spectral measures are isometry invariant and therefore allow for shape comparisons with minimal shape pre-processing. In particular, no registration, mapping, or remeshing is necessary. The discriminatory power of the 2D surface and 3D solid methods is demonstrated on a population of female caudate nuclei (a subcortical gray matter structure of the brain, involved in memory function, emotion processing, and learning) of normal control subjects and of subjects with schizotypal personality disorder. The behavior and properties of the Laplace-Beltrami eigenvalues and -functions are discussed extensively for both the Dirichlet and Neumann boundary condition showing advantages of the Neumann vs. the Dirichlet spectra in 3D. Furthermore, topological analyses employing the Morse-Smale complex (on the surfaces) and the Reeb graph (in the solids) are performed on selected eigenfunctions, yielding shape descriptors, that are capable of localizing geometric properties and detecting shape differences by indirectly registering topological features such as critical points, level sets and integral lines of the gradient field across subjects. The use of these topological features of the Laplace-Beltrami eigenfunctions in 2D and 3D for statistical shape analysis is novel.
Some Half-Row Sums from Pascal's Triangle via Laplace Transforms
ERIC Educational Resources Information Center
Dence, Thomas P.
2007-01-01
This article presents some identities on the sum of the entries in the first half of a row in Pascal's triangle. The results were discovered while the author was working on a problem involving Laplace transforms, which are used in proving of the identities.
Laplace transform approach for solving integral equations using computer algebra system
NASA Astrophysics Data System (ADS)
Paneva-Konovska, Jordanka; Nikolova, Yanka
2016-12-01
The Laplace transform method, along with Computer Algebra Systems (CAS) "Maple" v. 13, are extremely successfully applied for solving a class of integral equations with an arbitrary order, including fractional order integral equations. The combining of both powerful approaches allows students more quickly, enjoyable and thoroughly to master the material.
NASA Technical Reports Server (NTRS)
Chang, F.-C.; Mott, H.
1974-01-01
This paper presents a technique for the partial-fraction expansion of functions which are ratios of polynomials with real coefficients. The expansion coefficients are determined by writing the polynomials as Taylor's series and obtaining the Laurent series expansion of the function. The general formula for the inverse Laplace transform is also derived.
Numerical inversion of the Laplace transform in some problems of granular media dynamics
NASA Astrophysics Data System (ADS)
Yavich, Nikolay B.
2004-04-01
Approximated value for the vertical displacement of a surface bounding a half space and a layer laying on rigid foundation filled with granular medium caused by a vertical symmetric load is received here. The results obtained for Kandaurov standard linear medium model are used. This model takes in account an internal friction. The Papoulis method of numerical inversion of the Laplace transform is applied.
The kernel of Laplace-Beltrami operators with zero-radius potential or on decorated graphs
NASA Astrophysics Data System (ADS)
Tolchennikov, A. A.
2008-08-01
An isomorphism is described for the kernel of the Laplace operator \\Delta^{\\!\\Lambda} (determined by a Lagrangian plane \\Lambda\\subset\\mathbb C^k\\oplus\\mathbb C^k) with potential \\sum_{j=1}^kc_j\\delta_{q_j}(x) on a manifold. The isomorphism is given by \\Gamma\\colon\\ker\\Delta^{\\!\\Lambda}\\to\\Lambda\\cap\
University Teachers' Perspectives on the Role of the Laplace Transform in Engineering Education
ERIC Educational Resources Information Center
Holmberg, Margarita; Bernhard, Jonte
2017-01-01
The Laplace transform is an important tool in many branches of engineering, for example, electric and control engineering, but is also regarded as a difficult topic for students to master. We have interviewed 22 university teachers from five universities in three countries (Mexico, Spain and Sweden) about their views on relationships among…
Concentration of Laplace Eigenfunctions and Stabilization of Weakly Damped Wave Equation
NASA Astrophysics Data System (ADS)
Burq, N.; Zuily, C.
2016-08-01
In this article, we prove some universal bounds on the speed of concentration on small (frequency-dependent) neighbourhoods of sub-manifolds of L 2-norms of quasi modes for Laplace operators on compact manifolds. We deduce new results on the rate of decay of weakly damped wave equations.
Existence results for degenerate p(x)-Laplace equations with Leray-Lions type operators
NASA Astrophysics Data System (ADS)
Ho, Ky; Sim, Inbo
2017-01-01
We show the various existence results for degenerate $p(x)$-Laplace equations with Leray-Lions type operators. A suitable condition on degeneracy is discussed and proofs are mainly based on direct methods and critical point theories in Calculus of Variations. In particular, we investigate the various situations of the growth rates between principal operators and nonlinearities.
Laplace-Gauss and Helmholtz-Gauss paraxial modes in media with quadratic refraction index.
Kiselev, Aleksei P; Plachenov, Alexandr B
2016-04-01
The scalar theory of paraxial wave propagation in an axisymmetric medium where the refraction index quadratically depends on transverse variables is addressed. Exact solutions of the corresponding parabolic equation are presented, generalizing the Laplace-Gauss and Helmholtz-Gauss modes earlier known for homogeneous media. Also, a generalization of a zero-order asymmetric Bessel-Gauss beam is given.
On a class of nonlocal boundary value problems for the Laplace operator in a disk
NASA Astrophysics Data System (ADS)
Sadybekov, Makhmud; Torebek, Berikbol
2016-12-01
In this work we consider a nonlocal boundary value problem for the Laplace operator in a disk. A Newton potential is a particular case of the problem. We establish conditions of its Noetherian property, Fredholm property and well-posedness. We prove self-adjointness of the problem. We construct all the eigenvalues and eigenfunctions of the problem for a correct case.
An evolution infinity Laplace equation modelling dynamic elasto-plastic torsion
NASA Astrophysics Data System (ADS)
Messelmi, Farid
2016-09-01
We consider in this paper a parabolic partial differential equation involving the infinity Laplace operator and a Leray-Lions operator with no coercitive assumption. We prove the existence and uniqueness of the corresponding approached problem and we show that at the limit the solution solves the parabolic variational inequality arising in the elasto-plastic torsion problem.
Existence results for degenerate p(x)-Laplace equations with Leray-Lions type operators
NASA Astrophysics Data System (ADS)
Ho, Ky; Sim, Inbo
2017-01-01
We show the various existence results for degenerate $p(x)$-Laplace equations with Leray-Lions type operators. A suitable condition on degeneracy is discussed and proofs are mainly based on direct methods and critical point theories in Calculus of Variations. In particular, we investigate the various situations of the growth rates between principal operators and nonlinearities.
Cluster analysis of European Y-chromosomal STR haplotypes using the discrete Laplace method.
Andersen, Mikkel Meyer; Eriksen, Poul Svante; Morling, Niels
2014-07-01
The European Y-chromosomal short tandem repeat (STR) haplotype distribution has previously been analysed in various ways. Here, we introduce a new way of analysing population substructure using a new method based on clustering within the discrete Laplace exponential family that models the probability distribution of the Y-STR haplotypes. Creating a consistent statistical model of the haplotypes enables us to perform a wide range of analyses. Previously, haplotype frequency estimation using the discrete Laplace method has been validated. In this paper we investigate how the discrete Laplace method can be used for cluster analysis to further validate the discrete Laplace method. A very important practical fact is that the calculations can be performed on a normal computer. We identified two sub-clusters of the Eastern and Western European Y-STR haplotypes similar to results of previous studies. We also compared pairwise distances (between geographically separated samples) with those obtained using the AMOVA method and found good agreement. Further analyses that are impossible with AMOVA were made using the discrete Laplace method: analysis of the homogeneity in two different ways and calculating marginal STR distributions. We found that the Y-STR haplotypes from e.g. Finland were relatively homogeneous as opposed to the relatively heterogeneous Y-STR haplotypes from e.g. Lublin, Eastern Poland and Berlin, Germany. We demonstrated that the observed distributions of alleles at each locus were similar to the expected ones. We also compared pairwise distances between geographically separated samples from Africa with those obtained using the AMOVA method and found good agreement.
Improved FFT-based numerical inversion of Laplace transforms via fast Hartley transform algorithm
NASA Technical Reports Server (NTRS)
Hwang, Chyi; Lu, Ming-Jeng; Shieh, Leang S.
1991-01-01
The disadvantages of numerical inversion of the Laplace transform via the conventional fast Fourier transform (FFT) are identified and an improved method is presented to remedy them. The improved method is based on introducing a new integration step length Delta(omega) = pi/mT for trapezoidal-rule approximation of the Bromwich integral, in which a new parameter, m, is introduced for controlling the accuracy of the numerical integration. Naturally, this method leads to multiple sets of complex FFT computations. A new inversion formula is derived such that N equally spaced samples of the inverse Laplace transform function can be obtained by (m/2) + 1 sets of N-point complex FFT computations or by m sets of real fast Hartley transform (FHT) computations.
Convergent radial dispersion: a Laplace transform solution for aquifer tracer testing
Moench, A.F.
1989-01-01
A Laplace transform solution was obtained for the injection of a tracer in a well situated in a homogeneous aquifer where steady, horizontal, radially convergent flow has been established due to pumping at a second well. The standard advection-dispersion equation for mass transfer was used as the controlling equation. For boundary conditions, mass balances that account for mixing of the tracer with the fluid residing in the injection and pumping wells were used. The derived solution, which can be adapted for either resident or flux-averaged concentration, is of practical use only for the pumped well. This problem is of interest because it is easily applied to field determination of aquifer dispersivity and effective porosity. Breakthrough curves were obtained by numerical inversion of the Laplace transform solution. -from Author
Highly efficient manipulation of Laplace fields in film system with structured bilayer composite.
Lan, Chuwen; Lei, Ming; Bi, Ke; Li, Bo; Zhou, Ji
2016-12-26
Using metamaterials or transformation optics to manipulate Laplace fields, such as magnetic, electric and thermal fields, has become a research highlight. These studies, however, are usually limited to a bulk material system and to single field manipulation. In this paper, we focus on a film system and propose a general practical method applicable for such a system. In this method, the background film is covered with another one to construct a so-called "bilayer composite" to achieve required physical parameters. On the basis of the bilayer composite, a multi-physics cloak and a multi-physics concentrator for electric current and thermal flux are designed, fabricated, and demonstrated. This work provides an efficient way to control and manipulate single/ multi-physics Laplace fields like a dc electric field and a thermal field in a film system, which may find potential applications in IC technology, MEMS, and so on.
Rolling Element Bearing Fault Diagnosis Using Laplace-Wavelet Envelope Power Spectrum
NASA Astrophysics Data System (ADS)
Al-Raheem, Khalid F.; Roy, Asok; Ramachandran, K. P.; Harrison, D. K.; Grainger, Steven
2007-12-01
The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to identify faults occurring at the BCF. However, the computation of the ED is suffering to strictly define the resonance frequency band. In this paper, an alternative approach based on the Laplace-wavelet enveloped power spectrum is proposed. The Laplace-Wavelet shape parameters are optimized based on Kurtosis maximization criteria. The results for simulated as well as real bearing vibration signal show the effectiveness of the proposed method to extract the bearing fault characteristic frequencies from the resonant frequency band.
High resolution Laplace DLTS studies of defects in ion-implanted silicon
NASA Astrophysics Data System (ADS)
Evans-Freeman, J. H.; Abdelgader, N.; Kan, P. Y. Y.; Peaker, A. R.
2002-01-01
We have used high resolution Laplace deep level transient spectroscopy (LDLTS) to investigate defects in n-type silicon caused by implantation of Si, Ge or Er with doses of the order of 1×10 9 cm-2. These are compared with defects created in proton irradiated n-type silicon. Unlike the simple proton irradiated case, LDLTS spectra of ion implanted silicon show that there are many emission rates associated with defects with energies in the region of Ec-400 meV. We have carried out annealing studies and Laplace DLTS depth profiling and show that the complex spectra measured from a region less than half way through the implant simplify as the profile is moved through the implant and towards the tail. Annealing studies show that these defects survive an anneal that should remove the E-centre.
Research on temporal features of LEMP based on Laplace wavelet in time and frequency domain
NASA Astrophysics Data System (ADS)
Li, Qin; Zhong, Jianwei; Ai, Qing; Gao, Shihong
2015-12-01
In this paper, the fine-structures of lightning electromagnetic pulse (LEMP) including 19 pulses in preliminary breakdown, 37 stepped leaders, 8 dart leaders, 73 first return strokes, and 52 subsequent return strokes have been analyzed based on Laplace wavelet. The main characteristics of field waveforms are presented: the correlation coefficient, the dominant frequency, the peak energy and the spread distribution of the power spectrum. The instantaneous field peak pulse can be precisely located by the value of the correlation coefficient. The pulses of preliminary breakdown and leaders are found to radiate in the dominant frequency in the range 100 kHz to 1 MHz. The field radiated by the first return strokes dominantly lies under 100 kHz, whereas the subsequent return strokes under 50 kHz. The statistical results show that the Laplace wavelet is effective and can accurately determine time and frequency of the electromagnetic field of first and subsequent return strokes.
Analytic solution for American strangle options using Laplace-Carson transforms
NASA Astrophysics Data System (ADS)
Kang, Myungjoo; Jeon, Junkee; Han, Heejae; Lee, Somin
2017-06-01
A strangle has been important strategy for options when the trader believes there will be a large movement in the underlying asset but are uncertain of which way the movement will be. In this paper, we derive analytic formula for the price of American strangle options. American strangle options can be mathematically formulated into the free boundary problems involving two early exercise boundaries. By using Laplace-Carson Transform(LCT), we can derive the nonlinear system of equations satisfied by the transformed value of two free boundaries. We then solve this nonlinear system using Newton's method and finally get the free boundaries and option values using numerical Laplace inversion techniques. We also derive the Greeks for the American strangle options as well as the value of perpetual American strangle options. Furthermore, we present various graphs for the free boundaries and option values according to the change of parameters.
Numerical Laplace transform density of states calculation for medium and large molecules
NASA Astrophysics Data System (ADS)
Romanini, D.; Lehmann, K. K.
1993-04-01
A novel implementation of the Laplace transform method for the calculation of the density of states of molecules, for which the partition function can be explicitly given is described. It consists of doing the inverse Laplace transform numerically after multiplying the integrand by a smoothing factor. This evaluation is more accurate than the method of steepest descent, and the computation can still be done on a PC in a few minutes. By first order expansion of the partition function in the anharmonic parameters we have been able to calculate the density of states for a model molecule composed by anharmonically coupled anharmonic oscillators, which cannot be treated by the well known Beyer-Swinehart algorithm.
Transverse colon perforation due to carcinoma rectum: an unusual presentation against Laplace's law.
Sahoo, Manash Ranjan; Kumar, Anil; Jaiswal, Sunil; C, Basavaraja
2013-08-16
We present a case of distal large bowel obstruction, in the setting of a competent ileocaecal valve, the caecum is the most common site of perforation (for Laplace's law). We describe a case of obstruction at the rectum due to constricting carcinomatous growth, presenting with perforation of transverse colon (against Laplace's law). A 60-year-old women presented to the emergency department with acute abdominal pain. The pain was preceded by 3 days of intestinal obstruction. Clinically there was guarding and rigidity. Straight X-ray of the abdomen revealed free gas under diaphragm. Surgical exploration revealed transverse colon perforation with carcinoma of rectum. Loop transverse colostomy was performed as the patient was very sick. The patient improved slowly in the intensive care unit. To conclude, even though the caecum is the most common site for perforation in case of distal obstruction, perforation of transverse colon can occur otherwise as a unique presentation.
NASA Astrophysics Data System (ADS)
Gzyl, Henryk; ter Horst, Enrique; Villasana, Minaya
2015-02-01
In a previous paper we studied a method to determine the probability density of barrier crossing times by a Brownian motion from the knowledge of its Laplace transform. This knowledge combined with the method of maximum entropy yields quite good reconstructions. The aim of this work is to extend the previous analysis in two directions. On one hand, we consider diffusions with non constant coefficients. This forces us to determine the Laplace transform numerically or by means of simulations. On the other hand, and this is the gist of this note, as numerical problems involve errors, we consider as well two possible extensions of the maximum entropy procedure which allow us to incorporate those errors into the probability reconstruction process.
Flow to a well in a water-table aquifer: An improved laplace transform solution
Moench, A.F.
1996-01-01
An alternative Laplace transform solution for the problem, originally solved by Neuman, of constant discharge from a partially penetrating well in a water-table aquifer was obtained. The solution differs from existing solutions in that it is simpler in form and can be numerically inverted without the need for time-consuming numerical integration. The derivation invloves the use of the Laplace transform and a finite Fourier cosine series and avoids the Hankel transform used in prior derivations. The solution allows for water in the overlying unsaturated zone to be released either instantaneously in response to a declining water table as assumed by Neuman, or gradually as approximated by Boulton's convolution integral. Numerical evaluation yields results identical with results obtained by previously published methods with the advantage, under most well-aquifer configurations, of much reduced computation time.
The local counting function of operators of Dirac and Laplace type
NASA Astrophysics Data System (ADS)
Li, Liangpan; Strohmaier, Alexander
2016-06-01
Let P be a non-negative self-adjoint Laplace type operator acting on sections of a hermitian vector bundle over a closed Riemannian manifold. In this paper we review the close relations between various P-related coefficients such as the mollified spectral counting coefficients, the heat trace coefficients, the resolvent trace coefficients, the residues of the spectral zeta function as well as certain Wodzicki residues. We then use the Wodzicki residue to obtain results about the local counting function of operators of Dirac and Laplace type. In particular, we express the second term of the mollified spectral counting function of Dirac type operators in terms of geometric quantities and characterize those Dirac type operators for which this coefficient vanishes.
On the Analytical and Numerical Properties of the Truncated Laplace Transform
2014-05-01
In this dissertation, we construct efficient algorithms for the eval- uation of the singular value decomposition ( SVD ) of such operators. The approach...by the ONR grants #N00014-11-1-0718 and #N00014-10-1-0570 and the NSF grant #1309858. Keywords: Truncated Laplace Transform, SVD . Report Documentation...decomposition ( SVD ) of integral operators . . . . . . . . . . . . 13 2.6 Tridiagonal and five-diagonal matrices
Membrane Operational Impedance Spectra in Chara corallina Estimated by Laplace Transforms Analysis 1
Homblé, Fabrice; Jenard, André
1986-01-01
The membrane operational impedance spectrum of Chara corallina Klein ex Willd. (R. Brown) cells is investigated using Laplace transform analysis. The spectrum changes with both amplitude and sign of the electrical stimulation when time- and voltage-dependent K+ channels contribute to the membrane conductance. We compare the advantages and disadvantage of this technique for studying membrane impedance with those of the alternating current method and the white noise method. PMID:16664925
Operation Plumbbob. Program 2. Neutron and gamma radiation from Shot Laplace
Chiment, J.A.; Goetz, J.L.; Facer, G.C.
1984-10-31
The objectives of this experiment were to determine, for Shot Laplace, a 1.22-kt device fired late in Operation Plumbbob: (1) intensity and decay of the neuron-induced gammafield; (2) neutron flux and spectra as a function of distance; (3) neutron flux as a function of soil depth with certain selected detectors; and (4) neutron dose and initial gamma dose as a function of distance.
Temme, N.M.
1987-11-01
The analytical approach of Temme (1983 and 1985), based on uniform asymptotic expansions, is extended to an additional class of incomplete Laplace integrals. The terminology is introduced; the construction of the formal series is explained; representations for the remainders are derived; the asymptotic nature of the expansions is explored; and error bounds are determined. Numerical results are presented for the case of the incomplete beta function. 14 references.
A numerical inversion of a the Laplace transform solution to radial dispersion in a porous medium.
Moench, A.F.; Ogata, A.
1981-01-01
A special form of the numerical inversion of the Laplace transform described by Stehfest (1970) is applied to the transformed solution of dispersion in a radial flow system in a porous medium. The inversion is extremely simple to use because the weighting coefficients depend only on the number of terms used in the computation and not upon the transform solution as required by most numerical inversion techniques.-from Authors
Tests of Fit for Asymmetric Laplace Distributions with Applications on Financial Data
NASA Astrophysics Data System (ADS)
Fragiadakis, Kostas; Meintanis, Simos G.
2008-11-01
New goodness-of-fit tests for the family of asymmetric Laplace distributions are constructed. The proposed tests are based on a weighted integral incorporating the empirical characteristic function of suitably standardized data, and can be written in a closed form appropriate for computer implementation. Monte Carlo results show that the new procedure are competitive with classical goodness-of-fit methods. Applications with financial data are also included.
Solving nonlinear or stiff differential equations by Laplace homotopy analysis method(LHAM)
NASA Astrophysics Data System (ADS)
Chong, Fook Seng; Lem, Kong Hoong; Wong, Hui Lin
2015-10-01
The initial value problems of nonlinear or stiff ordinary differential equation appear in many fields of engineering science, particularly in the studies of electrical circuits, chemical reactions, wave vibration and so on. In this research, the standard homotopy analysis method hybrids with Laplace transform method to solve nonlinear and stiff differential equations. Using this modification, the problems solved by LHAM successfully yield good solutions. Some examples are examined to highlight the convenience and effectiveness of LHAM.
Myocardial wall thickening from gated magnetic resonance images using Laplace's equation
NASA Astrophysics Data System (ADS)
Prasad, M.; Ramesh, A.; Kavanagh, P.; Gerlach, J.; Germano, G.; Berman, D. S.; Slomka, P. J.
2009-02-01
The aim of our work is to present a robust 3D automated method for measuring regional myocardial thickening using cardiac magnetic resonance imaging (MRI) based on Laplace's equation. Multiple slices of the myocardium in short-axis orientation at end-diastolic and end-systolic phases were considered for this analysis. Automatically assigned 3D epicardial and endocardial boundaries were fitted to short-axis and long axis slices corrected for breathold related misregistration, and final boundaries were edited by a cardiologist if required. Myocardial thickness was quantified at the two cardiac phases by computing the distances between the myocardial boundaries over the entire volume using Laplace's equation. The distance between the surfaces was found by computing normalized gradients that form a vector field. The vector fields represent tangent vectors along field lines connecting both boundaries. 3D thickening measurements were transformed into polar map representation and 17-segment model (American Heart Association) regional thickening values were derived. The thickening results were then compared with standard 17-segment 6-point visual scoring of wall motion/wall thickening (0=normal; 5=greatest abnormality) performed by a consensus of two experienced imaging cardiologists. Preliminary results on eight subjects indicated a strong negative correlation (r=-0.8, p<0.0001) between the average thickening obtained using Laplace and the summed segmental visual scores. Additionally, quantitative ejection fraction measurements also correlated well with average thickening scores (r=0.72, p<0.0001). For segmental analysis, we obtained an overall correlation of -0.55 (p<0.0001) with higher agreement along the mid and apical regions (r=-0.6). In conclusion 3D Laplace transform can be used to quantify myocardial thickening in 3D.
I termini di Cassini e Laplace della rifrazione atmosferica misurati alla Meridiana Clementina
NASA Astrophysics Data System (ADS)
Sigismondi, Costantino
2016-05-01
The measures of the atmospheric refraction terms of Cassini and Laplace are made at the Clementine Meridian Line of S. Maria degli Angeli in Rome by comparing the observed positions of the center of the Sun with the ones calculated without atmosphere. Three linear systems with the data of 21 Dec 2015; 18 Jan and 6 Feb 2016 give the refraction terms of tan(z) and tan3(z).
Using inverse Laplace transform for the solution of a flood routing problem
NASA Astrophysics Data System (ADS)
Saboorkazeran, H.; Maghrebi, M. F.
2012-08-01
The inverse Laplace transform is of great importance in mathematical sciences when an analytical solution exists in Laplace domain. A new solution of the linearized St. Venant equations (LSVE) has been obtained for flood routing. The LSVE has been previously used by many researchers. In the formulation, the linearized form of the Manning formula is combined with the LSVE to get a Laplace transformable, simplified set of equations. There are different simplifications in the literature to get an analytical solution in time domain, not applicable to complicated form of equations. The results of discharge and depth predictions show that improved De Hoog algorithm provides a solution with very small error, when applied to the LSVE. Moreover, the model solution is compared against the numerical solution of the LSVE using the well-known Preissmann implicit finite difference scheme. The model outputs indicate a very good agreement with the numerical solution. It is notable that in the results reported by Litrico and Fromion [1], the LSVE was limited to maximum variation of 5% in discharge, however in the current paper the range of the variation is reached to 50% of the initial discharge.
NASA Astrophysics Data System (ADS)
Liang, Yingjie; Chen, Wen; Magin, Richard L.
2016-07-01
Analytical solutions to the fractional diffusion equation are often obtained by using Laplace and Fourier transforms, which conveniently encode the order of the time and the space derivatives (α and β) as non-integer powers of the conjugate transform variables (s, and k) for the spectral and the spatial frequencies, respectively. This study presents a new solution to the fractional diffusion equation obtained using the Laplace transform and expressed as a Fox's H-function. This result clearly illustrates the kinetics of the underlying stochastic process in terms of the Laplace spectral frequency and entropy. The spectral entropy is numerically calculated by using the direct integration method and the adaptive Gauss-Kronrod quadrature algorithm. Here, the properties of spectral entropy are investigated for the cases of sub-diffusion and super-diffusion. We find that the overall spectral entropy decreases with the increasing α and β, and that the normal or Gaussian case with α = 1 and β = 2, has the lowest spectral entropy (i.e., less information is needed to describe the state of a Gaussian process). In addition, as the neighborhood over which the entropy is calculated increases, the spectral entropy decreases, which implies a spatial averaging or coarse graining of the material properties. Consequently, the spectral entropy is shown to provide a new way to characterize the temporal correlation of anomalous diffusion. Future studies should be designed to examine changes of spectral entropy in physical, chemical and biological systems undergoing phase changes, chemical reactions and tissue regeneration.
Shao, Yan-Lin Faltinsen, Odd M.
2014-10-01
We propose a new efficient and accurate numerical method based on harmonic polynomials to solve boundary value problems governed by 3D Laplace equation. The computational domain is discretized by overlapping cells. Within each cell, the velocity potential is represented by the linear superposition of a complete set of harmonic polynomials, which are the elementary solutions of Laplace equation. By its definition, the method is named as Harmonic Polynomial Cell (HPC) method. The characteristics of the accuracy and efficiency of the HPC method are demonstrated by studying analytical cases. Comparisons will be made with some other existing boundary element based methods, e.g. Quadratic Boundary Element Method (QBEM) and the Fast Multipole Accelerated QBEM (FMA-QBEM) and a fourth order Finite Difference Method (FDM). To demonstrate the applications of the method, it is applied to some studies relevant for marine hydrodynamics. Sloshing in 3D rectangular tanks, a fully-nonlinear numerical wave tank, fully-nonlinear wave focusing on a semi-circular shoal, and the nonlinear wave diffraction of a bottom-mounted cylinder in regular waves are studied. The comparisons with the experimental results and other numerical results are all in satisfactory agreement, indicating that the present HPC method is a promising method in solving potential-flow problems. The underlying procedure of the HPC method could also be useful in other fields than marine hydrodynamics involved with solving Laplace equation.
From entropy-maximization to equality-maximization: Gauss, Laplace, Pareto, and Subbotin
NASA Astrophysics Data System (ADS)
Eliazar, Iddo
2014-12-01
The entropy-maximization paradigm of statistical physics is well known to generate the omnipresent Gauss law. In this paper we establish an analogous socioeconomic model which maximizes social equality, rather than physical disorder, in the context of the distributions of income and wealth in human societies. We show that-on a logarithmic scale-the Laplace law is the socioeconomic equality-maximizing counterpart of the physical entropy-maximizing Gauss law, and that this law manifests an optimized balance between two opposing forces: (i) the rich and powerful, striving to amass ever more wealth, and thus to increase social inequality; and (ii) the masses, struggling to form more egalitarian societies, and thus to increase social equality. Our results lead from log-Gauss statistics to log-Laplace statistics, yield Paretian power-law tails of income and wealth distributions, and show how the emergence of a middle-class depends on the underlying levels of socioeconomic inequality and variability. Also, in the context of asset-prices with Laplace-distributed returns, our results imply that financial markets generate an optimized balance between risk and predictability.
NASA Astrophysics Data System (ADS)
Pashos, G.; Kokkoris, G.; Papathanasiou, A. G.; Boudouvis, A. G.
2016-01-01
The Minimum Energy Paths (MEPs) of wetting transitions on pillared surfaces are computed with the Young-Laplace equation, augmented with a pressure term that accounts for liquid-solid interactions. The interactions are smoothed over a short range from the solid phase, therefore facilitating the numerical solution of problems concerning wetting on complex surface patterns. The patterns may include abrupt geometric features, e.g., arrays of rectangular pillars, where the application of the unmodified Young-Laplace is not practical. The MEPs are obtained by coupling the augmented Young-Laplace with the modified string method from which the energy barriers of wetting transitions are eventually extracted. We demonstrate the method on a wetting transition that is associated with the breakdown of superhydrophobic behavior, i.e., the transition from the Cassie-Baxter state to the Wenzel state, taking place on a superhydrophobic pillared surface. The computed energy barriers quantify the resistance of the system to these transitions and therefore, they can be used to evaluate superhydrophobic performance or provide guidelines for optimal pattern design.
On the applicability of Young-Laplace equation for nanoscale liquid drops
NASA Astrophysics Data System (ADS)
Yan, Hong; Wei, Jiuan; Cui, Shuwen; Xu, Shenghua; Sun, Zhiwei; Zhu, Ruzeng
2016-03-01
Debates continue on the applicability of the Young-Laplace equation for droplets, vapor bubbles and gas bubbles in nanoscale. It is more meaningful to find the error range of the Young-Laplace equation in nanoscale instead of making the judgement of its applicability. To do this, for seven liquid argon drops (containing 800, 1000, 1200, 1400, 1600, 1800, or 2000 particles, respectively) at T = 78 K we determined the radius of surface of tension R s and the corresponding surface tension γ s by molecular dynamics simulation based on the expressions of R s and γ s in terms of the pressure distribution for droplets. Compared with the two-phase pressure difference directly obtained by MD simulation, the results show that the absolute values of relative error of two-phase pressure difference given by the Young-Laplace equation are between 0.0008 and 0.027, and the surface tension of the argon droplet increases with increasing radius of surface of tension, which supports that the Tolman length of Lennard-Jones droplets is positive and that Lennard-Jones vapor bubbles is negative. Besides, the logic error in the deduction of the expressions of the radius and the surface tension of surface of tension, and in terms of the pressure distribution for liquid drops in a certain literature is corrected.
A family of driving forces to suppress chaos in jerk equations: Laplace domain design.
Femat, Ricardo; Campos-Delgado, Daniel U; Martínez-López, Francisco J
2005-12-01
A family of driving forces is discussed in the context of chaos suppression in the Laplace domain. This idea can be attained by increasing the order of the polynomial in the expressions of the driving force to account for the robustness and/or the performance of the closed loop. The motivation arises from the fact that chaotic systems can be controlled by increasing the order of the Laplace controllers even to track arbitrary orbits. However, a larger order in the driving forces can induce an undesirable frequency response, and the control efforts can result in either peaking or large energy accumulation. We overcame these problems by showing that considering the frequency response (interpreted by norms), the closed-loop execution can be improved by designing the feedback suppressor in the Laplace domain. In this manner, the stabilization of the chaotic behavior in jerk-like systems is achieved experimentally. Jerk systems are particularly sensitive to control performance (and robustness issues) because the acceleration time-derivative is involved in their models. Thus, jerky systems are especially helped by a robust control design.
Laplace-domain waveform modeling and inversion for the 3D acoustic-elastic coupled media
NASA Astrophysics Data System (ADS)
Shin, Jungkyun; Shin, Changsoo; Calandra, Henri
2016-06-01
Laplace-domain waveform inversion reconstructs long-wavelength subsurface models by using the zero-frequency component of damped seismic signals. Despite the computational advantages of Laplace-domain waveform inversion over conventional frequency-domain waveform inversion, an acoustic assumption and an iterative matrix solver have been used to invert 3D marine datasets to mitigate the intensive computing cost. In this study, we develop a Laplace-domain waveform modeling and inversion algorithm for 3D acoustic-elastic coupled media by using a parallel sparse direct solver library (MUltifrontal Massively Parallel Solver, MUMPS). We precisely simulate a real marine environment by coupling the 3D acoustic and elastic wave equations with the proper boundary condition at the fluid-solid interface. In addition, we can extract the elastic properties of the Earth below the sea bottom from the recorded acoustic pressure datasets. As a matrix solver, the parallel sparse direct solver is used to factorize the non-symmetric impedance matrix in a distributed memory architecture and rapidly solve the wave field for a number of shots by using the lower and upper matrix factors. Using both synthetic datasets and real datasets obtained by a 3D wide azimuth survey, the long-wavelength component of the P-wave and S-wave velocity models is reconstructed and the proposed modeling and inversion algorithm are verified. A cluster of 80 CPU cores is used for this study.
NASA Technical Reports Server (NTRS)
Lyusternik, L. A.
1980-01-01
The mathematics involved in numerically solving for the plane boundary value of the Laplace equation by the grid method is developed. The approximate solution of a boundary value problem for the domain of the Laplace equation by the grid method consists of finding u at the grid corner which satisfies the equation at the internal corners (u=Du) and certain boundary value conditions at the boundary corners.
NASA Astrophysics Data System (ADS)
Fabijonas, Bruce R.
2002-09-01
We examine a Maple implementation of two distinct approaches to Laplace's method used to obtain asymptotic expansions of Laplace-type integrals. One algorithm uses power series reversion, whereas the other expands all quantities in Taylor or Puiseux series. These algorithms are used to derive asymptotic expansions for the real valued modified Bessel functions of pure imaginary order and real argument that mimic the well-known corresponding expansions for the unmodified Bessel functions.
NASA Astrophysics Data System (ADS)
Takatsuka, Akio; Ten-No, Seiichiro; Hackbusch, Wolfgang
2008-07-01
We implement the minimax approximation for the decomposition of energy denominators in Laplace-transformed Møller-Plesset perturbation theories. The best approximation is defined by minimizing the Chebyshev norm of the quadrature error. The application to the Laplace-transformed second order perturbation theory clearly shows that the present method is much more accurate than other numerical quadratures. It is also shown that the error in the energy decays almost exponentially with respect to the number of quadrature points.
2010-01-01
Micropolar fluids Dipolar fluids a b s t r a c t The exact inverses of a class of Laplace transforms involving doubly-nested square roots and two branch...mechanics, for a micropolar fluid is determined. Published by Elsevier Ltd. 1. Introduction and problem formulation Using the Laplace transform, we...to the case of micropolar fluids, the theory of which was formulated by Eringen (1966). In doing so, we also extend the re- sults of Jordan et al
NASA Astrophysics Data System (ADS)
Zhang, Dong; Zhang, Xiaolei; Yuan, Jianzheng; Ke, Rui; Yang, Yan; Hu, Ying
2016-01-01
The Laplace-Fourier domain full waveform inversion can simultaneously restore both the long and intermediate short-wavelength information of velocity models because of its unique characteristics of complex frequencies. This approach solves the problem of conventional frequency-domain waveform inversion in which the inversion result is excessively dependent on the initial model due to the lack of low frequency information in seismic data. Nevertheless, the Laplace-Fourier domain waveform inversion requires substantial computational resources and long computation time because the inversion must be implemented on different combinations of multiple damping constants and multiple frequencies, namely, the complex frequencies, which are much more numerous than the Fourier frequencies. However, if the entire target model is computed on every complex frequency for the Laplace-Fourier domain inversion (as in the conventional frequency domain inversion), excessively redundant computation will occur. In the Laplace-Fourier domain waveform inversion, the maximum depth penetrated by the seismic wave decreases greatly due to the application of exponential damping to the seismic record, especially with use of a larger damping constant. Thus, the depth of the area effectively inverted on a complex frequency tends to be much less than the model depth. In this paper, we propose a method for quantitative estimation of the effective inversion depth in the Laplace-Fourier domain inversion based on the principle of seismic wave propagation and mathematical analysis. According to the estimated effective inversion depth, we can invert and update only the model area above the effective depth for every complex frequency without loss of accuracy in the final inversion result. Thus, redundant computation is eliminated, and the efficiency of the Laplace-Fourier domain waveform inversion can be improved. The proposed method was tested in numerical experiments. The experimental results show that
Investigation of Jovian satellites and the origin of Jovian system by LAPLACE
NASA Astrophysics Data System (ADS)
Sasaki, Sho; Okada, Tatsuaki; Yamaji, Atsushi; Fujimoto, Masaki; Kasaba, Yasumasa; Kimura, Jun; Ikoma, Masahiro; Hussmann, Hauke; Kuramoto, Kiyoshi
LAPLACE (ESA-JAXA joint mission for the Jovian system) was selected as one of future ESA scientific missions Cosmic Vision in October 2007. LAPLACE is a mission with three spacecrafts aiming at coordinated observations of Jovian satellites and the magnetosphere, atmosphere and interior of Jupiter. An orbiter around Europa or Ganymede is involved. There is a possibility that JAXA (Japan Aerospace Exploration Agency) will take a role on the magnetosphere spinner. Japanese scientists working on the origin and evolution of Jupiter, satellite evolution, and astrobiology have been participating in the LAPLACE working group in Japan. Detailed observation of Jovian satellites Europa, Ganymede, Callisto and Io as well as smaller satellites such as Amalthea would be important also for the study of the origin of Jovian system. Resurfacing processes on Europa and Ganymede should be studied to know the properties of the internal oceans. The processes can be investigated by infrared observation for salt minerals and amorphous/crystal ices. Not only the thickness of icy crust of Europa but also thickness of the ocean and its bottom topography should be important targets, which would be investigated by gravity and magnetism measurements. For both Europa and Ganymede, the surface layering and structure of icy crust should be an interesting geological target, which will be clarified by subsurface radar. In Japan, KAGUYA is observing the Moon, and Venus remote sensing mission (PLANET-C) and Mercury mission Bepi Colombo will be launched in 2011 and 2013, respectively. Several instruments such as cameras, spectrometers, a laser altimeter, a radar, a magnetometer, plasma instruments, and a dust detector should come from the heritage of instruments on board KAGUYA, PLANET-C, and BepiColombo.
Laplace transform homotopy perturbation method for the approximation of variational problems.
Filobello-Nino, U; Vazquez-Leal, H; Rashidi, M M; Sedighi, H M; Perez-Sesma, A; Sandoval-Hernandez, M; Sarmiento-Reyes, A; Contreras-Hernandez, A D; Pereyra-Diaz, D; Hoyos-Reyes, C; Jimenez-Fernandez, V M; Huerta-Chua, J; Castro-Gonzalez, F; Laguna-Camacho, J R
2016-01-01
This article proposes the application of Laplace Transform-Homotopy Perturbation Method and some of its modifications in order to find analytical approximate solutions for the linear and nonlinear differential equations which arise from some variational problems. As case study we will solve four ordinary differential equations, and we will show that the proposed solutions have good accuracy, even we will obtain an exact solution. In the sequel, we will see that the square residual error for the approximate solutions, belongs to the interval [0.001918936920, 0.06334882582], which confirms the accuracy of the proposed methods, taking into account the complexity and difficulty of variational problems.
Laplace DLTS investigation of transition metal-hydrogen complexes in germanium
NASA Astrophysics Data System (ADS)
Gurimskaya, Y.; Mesli, A.
2014-02-01
High-resolution Laplace DLTS technique has been used to examine fine structures in the carrier emission processes hidden in the broad conventional DLTS peaks recorded in germanium samples, doped by several transition metals - Ni, Cr and Fe. These structures are found to be correlated with the acceptors, related to mentioned impurities, and also with possible presence of hydrogen-related defects. A link explaining interaction of transition metals with hydrogen due to the applied chemical treatment during sample preparation process is revealed and compared to what is known in silicon.
NASA Astrophysics Data System (ADS)
Vatsala, Aghalaya S.; Sowmya, M.
2017-01-01
Study of nonlinear sequential fractional differential equations of Riemann-Lioville type and Caputo type initial value problem are very useful in applications. In order to develop any iterative methods to solve the nonlinear problems, we need to solve the corresponding linear problem. In this work, we develop Laplace transform method to solve the linear sequential Riemann-Liouville fractional differential equations as well as linear sequential Caputo fractional differential equations of order nq which is sequential of order q. Also, nq is chosen such that (n-1) < nq < n. All our results yield the integer results as a special case when q tends to 1.
Benchmarks of 3D Laplace Equation Solvers in a Cubic Configuration for Streamer Simulation
NASA Astrophysics Data System (ADS)
Joseph-Marie, Plewa; Olivier, Ducasse; Philippe, Dessante; Carolyn, Jacobs; Olivier, Eichwald; Nicolas, Renon; Mohammed, Yousfi
2016-05-01
The aim of this paper is to test a developed SOR R&B method using the Chebyshev accelerator algorithm to solve the Laplace equation in a cubic 3D configuration. Comparisons are made in terms of precision and computing time with other elliptic equation solvers proposed in the open source LIS library. The first results, obtained by using a single core on a HPC, show that the developed SOR R&B method is efficient when the spectral radius needed for the Chebyshev acceleration is carefully pre-estimated. Preliminary results obtained with a parallelized code using the MPI library are also discussed when the calculation is distributed over one hundred cores.
The application of the Galerkin method to solving PIES for Laplace's equation
NASA Astrophysics Data System (ADS)
Bołtuć, Agnieszka; Zieniuk, Eugeniusz
2016-06-01
The paper presents the application of the Galerkin method to solving the parametric integral equation system (PIES) on the example of Laplace's equation. The main aim of the paper is the analysis of the effectiveness of two methods for PIES solving: the collocation method and the Galerkin method. Researches were performed on two examples with analytical solutions. Tests concern mainly the accuracy of obtained numerical solutions and their stability. For both analyzed methods calculations were made with the various number of expressions in the approximation series, whilst in the collocation method two variants of the arrangement of collocation points were considered. We also compared the complexity of both methods using the execution time.
A method extracting solar cell parameters from spectral response by inverse laplace transform
NASA Astrophysics Data System (ADS)
Tuominen, E.; Acerbis, M.; Hovinen, A.; Siirtola, T.; Sinkkonen, J.
1997-01-01
A mathematical method to interpret spectral responses measured from solar cells has been developed. Taking an inverse Laplace transform from the spectral response of a solar cell the spatial dependent collection efficiency of the cell can be obtained. Several important material parameters of the solar cell can be extracted from this function. Applying this method the properties of the solar cell can be investigated without applying characterization methods to the cell itself. We have applied the method both to simulated solar cells andto real solar cells.
High order numerical differentiation and approximation of Laplace fields using regular grid data
NASA Astrophysics Data System (ADS)
Berdnikov, A. S.
2011-07-01
Specialized numerical schemes for calculation of high order field derivatives are considered. The input data are a regular rectangular mesh with potential values at its nodes, the output data are high order derivative values at grid nodes and associated expressions which enable the calculation of potentials, field values or high order derivatives inside a grid cell with high accuracy. An important feature is that differentiation and approximation techniques are based on a priori knowledge about the Laplace equation which allow the production of numerical schemes with higher order properties.
Variations of (pseudo-)rotations and the Laplace-Beltrami operator on homogeneous spaces
Brezov, D. S.; Mladenova, C. D.; Mladenov, I. M.
2015-10-28
In this paper we obtain the Lie derivatives of the scalar parameters in the generalized Euler decomposition with respect to arbitrary axes under left and right deck transformations. This problem can be directly related to the representation of the angular momentum in quantum mechanics. As a particular example, we calculate the angular momentum and the corresponding quantum hamiltonian in the standard Euler and Bryan representations. Similarly, in the hyperbolic case, the Laplace-Beltrami operator is retrieved for the Iwasawa decomposition. The case of two axes is considered as well.
Zeta functions of Dirac and Laplace-type operators over finite cylinders
NASA Astrophysics Data System (ADS)
Kirsten, Klaus; Loya, Paul; Park, Jinsung
2006-08-01
In this paper, a complete description of the zeta functions and corresponding zeta determinants for Dirac and Laplace-type operators over finite cylinders using the contour integration method, for example described in [K. Kirsten, Spectral Functions in Mathematics and Physics, Chapman & Hall/CRC Press, Boca Raton, 2001] is given. Different boundary conditions, local and non-local ones, are considered. The method is shown to be very powerful in that it is easily adapted to each situation and in that answers are very elegantly obtained.
Bicubic B-spline interpolation method for two-dimensional Laplace's equations
NASA Astrophysics Data System (ADS)
Abd Hamid, Nur Nadiah; Majid, Ahmad Abd.; Ismail, Ahmad Izani Md.
2013-04-01
Two-dimensional Laplace's equation is solved using bicubic B-spline interpolation method. An arbitrary surface with some unknown coefficients is generated using bicubic B-spline surface's formula. This surface is presumed to be the solution for the equation. The values of the coefficients are calculated by spline interpolation technique using the corresponding differential equations and boundary conditions. This method produces approximated analytical solution for the equation. A numerical example will be presented along with a comparison of the results with finite element and isogeometrical methods.
Improvements on the minimax algorithm for the Laplace transformation of orbital energy denominators
Helmich-Paris, Benjamin Visscher, Lucas
2016-09-15
We present a robust and non-heuristic algorithm that finds all extremum points of the error distribution function of numerically Laplace-transformed orbital energy denominators. The extremum point search is one of the two key steps for finding the minimax approximation. If pre-tabulation of initial guesses is supposed to be avoided, strategies for a sufficiently robust algorithm have not been discussed so far. We compare our non-heuristic approach with a bracketing and bisection algorithm and demonstrate that 3 times less function evaluations are required altogether when applying it to typical non-relativistic and relativistic quantum chemical systems.
Axial and polar gravitational wave equations in a de Sitter expanding universe by Laplace transform
NASA Astrophysics Data System (ADS)
Viaggiu, Stefano
2017-02-01
In this paper we study the propagation in a de Sitter universe of gravitational waves generated by perturbating some unspecified spherical astrophysical object in the frequencies domain. We obtain the axial and polar perturbation equations in a cosmological de Sitter universe in the usual comoving coordinates, the coordinates we occupy in our galaxy. We write down the relevant equations in terms of Laplace transform with respect to the comoving time t instead of the usual Fourier one that is no longer available in a cosmological context. Both axial and polar perturbation equations are expressed in terms of a non trivial mixture of retarded-advanced metric coefficients with respect to the Laplace parameter s (complex translation). The axial case is studied in more detail. In particular, the axial perturbations can be reduced to a master linear second-order differential equation in terms of the Regge-Wheeler function Z where a coupling with a retarded Z with respect to the cosmological time t is present. It is shown that a de Sitter expanding universe can change the frequency ω of a gravitational wave as perceived by a comoving observer. The polar equations are much more involved. Nevertheless, we show that the polar perturbations can also be expressed in terms of four independent integrable differential equations.
Estimate for the decay rate of the general term of the laplace series for the geopotential
NASA Astrophysics Data System (ADS)
Kholshevnikov, K. V.; Shaidulin, V. Sh.
2011-02-01
The exact estimates with respect to the uniform (Chebyshev) norm of the general term V n of the Laplace series in spherical harmonics for the gravitational potential of a planet are known to be functions of the differential properties of distribution of masses. However, it is difficult to use them in practice because the norm for large n is difficult to calculate. The mean square (Euclidean) norm, however, is used almost entirely in applied research, and so the translation of the estimates from one norm to the other can be effected only in particular cases. In the present paper, a power law estimate of the general term of the Laplace series with respect to the mean square norm is obtained, and its parameters are evaluated numerically. For the EGM2008 geopotential model (Pavlis et al., 2008), the exponent ranges between 2.7 and 3.4. Preliminary calculations are made for a model body for which the harmonic factors are known exactly. A cautious conclusion is made: the geopotential model put forward is capable of adequately describing spherical harmonics for n ≤ 1000; for 1000 ≤ n ≤ 2000 the model gives a correct description, at least qualitatively; for larger n the spherical harmonics of the model do not correspond to reality.
Energy state distributions at oxide-semiconductor interfaces investigated by Laplace DLTS
NASA Astrophysics Data System (ADS)
Dobaczewski, L.; Markevich, V. P.; Kruszewski, P.; Hawkins, I. D.; Peaker, A. R.
2009-12-01
At disordered Si/SiO2 interfaces the lattice mismatching results in dangling bond Pb centres forming a rather broad distribution of energy states. In this study these energy distributions have been determined using isothermal current Laplace deep level transient spectroscopy (DLTS) for the (1 0 0) and (1 1 1) interface orientations. The (1 1 1) distribution is 0.08 eV broad and centred at 0.38 eV below the silicon conduction band. This is consistent with only Pb0 states being present. While for the (1 0 0) orientation this distribution is broader (0.1 eV) and deeper (0.43 eV) on the energy scale. Detailed studies revealed two types of the interface states in this broad distribution: one similar to the (1 1 1) orientation while the other has a negative-U character in which the emission rate versus surface potential dependence is qualitatively different from that observed for Pb0 and is presumed to be Pb1. Discrepancies between Pb states energy distributions obtained with a use of the isothermal Laplace and conventional DLTS measurements are discussed. The presented experimental procedure can be used for analysis of interface states observed at interfaces of other semiconductor-oxide/dielectric systems.
NASA Astrophysics Data System (ADS)
Yang, Bian-Xia; Sun, Hong-Rui; Feng, Zhaosheng
In this paper, we are concerned with the unilateral global bifurcation structure of fractional differential equation (‑Δ)αu(x) = λa(x)u(x) + F(x,u,λ),x ∈ Ω,u = 0,inℝN\\Ω with nondifferentiable nonlinearity F. It shows that there are two distinct unbounded subcontinua 𝒞+ and 𝒞‑ consisting of the continuum 𝒞 emanating from [λ1 ‑ d,λ1 + d] ×{0}, and two unbounded subcontinua 𝒟+ and 𝒟‑ consisting of the continuum 𝒟 emanating from [λ1 ‑d¯,λ1 + d¯] ×{∞}. As an application of this unilateral global bifurcation results, we present the existence of the principal half-eigenvalues of the half-linear fractional eigenvalue problem. Finally, we deal with the existence of constant sign solutions for a class of fractional nonlinear problems. Main results of this paper generalize the known results on classical Laplace operators to fractional Laplace operators.
Deep levels of vacancy-hydrogen centers in silicon studied by Laplace DLTS
NASA Astrophysics Data System (ADS)
Bonde Nielsen, K.; Dobaczewski, L.; Goscinski, K.; Bendesen, R.; Andersen, Ole; Bech Nielsen, B.
1999-12-01
We identify the acceptor levels (-/0) of the VH and V2H defects in silicon from comparison of DLTS and EPR annealing data. The levels are very close to each other and close to the acceptor level of the PV defect (the E-center) as well. In order to separate them, we have applied the high-resolution technique of Laplace DLTS and compared the formation and annealing properties of defects generated by implantation of hydrogen or helium. We further applied Laplace DLTS in combination with uniaxial stress to study the acceptor level at Ec-Et=0.31 eV previously assigned to a vacancy-hydrogen-oxygen defect. We find, in accordance with recent EPR measurements, that the defect displays orthorhombic-I symmetry and rule out that it contains two hydrogen atoms. The defect can be understood as a single hydrogen atom bound inside the A-center, the well-known VO defect of silicon, and we denote it VOH accordingly. The observed orthorhombic-I symmetry arises because the hydrogen atom (at T=160 K) swiftly jumps among two equivalent sites across the (1 1 0) plane that contains the Si-O-Si bond. Previous studies have shown that hydrogenation of oxygen-rich electron-irradiated samples leads to the formation of VOH with simultaneous depletion of the A-center. Our structural data are in accordance with this dynamic behavior.
The Classical Laplace Plane and Its use as a Stable Disposal Orbit for GEO
NASA Astrophysics Data System (ADS)
Rosengren, A.; Scheeres, D.; McMahon, J.
2013-09-01
The geosynchronous Earth orbit (GEO) is the most susceptible region to space debris because there is no natural cleansing mechanism, such as atmospheric drag. Placing satellites in super-synchronous disposal orbits at the ends of their operational lifetimes has been recommended and practiced as one possible means of protecting this environment. The discovery of the high area-to-mass ratio (HAMR) debris population in near geosynchronous orbit (ca. 2004) raises concern for the long-term sustainability of this unique resource. It is currently believed that HAMR objects are sheets of multilayer insulation detaching from satellites in GEO disposal orbits due to surface degradation and material deterioration. The low energy release of HAMR objects from aging satellites abandoned in disposal orbits is not directly addressed in the national policies that established the graveyard. The current disposal regions cannot account for the large solar radiation pressure (SRP) perturbations of HAMR objects, implying that these storage orbits are not well suited as a graveyard. The orbital dynamics of uncontrolled GEO satellites is governed by the oblateness of the Earth and luni-solar gravitational interactions. By itself, Earth's oblateness causes the pole of the orbital plane to precess around Earth's rotation pole. Lunisolar perturbations will have a similar effect, but the precession will now take place about the orbit poles of the Moon and the Sun, respectively. The classical Laplace plane is the mean reference plane about whose axis the satellite's orbit precesses. On the Laplace place, the secular orbital evolution driven by the combined effects of these perturbations is zero, so that the orbits are frozen. The Laplace plane at GEO lies between the plane of the Earth's equator and that of the ecliptic, passing through their intersection, and has an inclination of about 7.5 degrees relative to Earth's equator. The uncontrolled GEO satellites precess at a constant inclination
Massopust, P.R.
1997-08-01
All solutions of an in its angular coordinates continuously perturbed Laplace-Beltrami equation in the open unit ball IB{sup n+2} {contained_in} IR{sup n+2}, n {ge} 1, are characterized. Moreover, it is shown that such pertubations yield distributional boundary values which are different from, but algebraically and topologically equivalent to, the hyperfunctions of Lions & Magenes. This is different from the case of radially perturbed Laplace-Beltrami operators (cf. [7]) where one has stability of distributional boundary values under such perturbations.
Identifying the most likely contributors to a Y-STR mixture using the discrete Laplace method.
Andersen, Mikkel Meyer; Eriksen, Poul Svante; Mogensen, Helle Smidt; Morling, Niels
2015-03-01
In some crime cases, the male part of the DNA in a stain can only be analysed using Y chromosomal markers, e.g. Y-STRs. This may be the case in e.g. rape cases, where the male components can only be detected as Y-STR profiles, because the fraction of male DNA is much smaller than that of female DNA, which can mask the male results when autosomal STRs are investigated. Sometimes, mixtures of Y-STRs are observed, e.g. in rape cases with multiple offenders. In such cases, Y-STR mixture analysis is required, e.g. by mixture deconvolution, to deduce the most likely DNA profiles from the contributors. We demonstrate how the discrete Laplace method can be used to separate a two person Y-STR mixture, where the Y-STR profiles of the true contributors are not present in the reference dataset, which is often the case for Y-STR profiles in real case work. We also briefly discuss how to calculate the weight of the evidence using the likelihood ratio principle when a suspect's Y-STR profile fits into a two person mixture. We used three datasets with between 7 and 21 Y-STR loci: Denmark (n=181), Somalia (n=201) and Germany (n=3443). The Danish dataset with 21 loci was truncated to 15 and 10 loci to examine the effect of the number of loci. For each of these datasets, an out of sample simulation study was performed: A total of 550 mixtures were composed by randomly sampling two haplotypes, h1 and h2, from the dataset. We then used the discrete Laplace method on the remaining data (excluding h1 and h2) to rank the contributor pairs by the product of the contributors' estimated haplotype frequencies. Successful separation of mixtures (defined by the observation that the true contributor pair was among the 10 most likely contributor pairs) was found in 42-52% of the cases for 21 loci, 69-75% for 15 loci and 92-99% for 10 loci or less depending on the dataset and how the discrete Laplace model was chosen. Y-STR mixtures with many loci are difficult to separate, but even haplotypes
LAPLACE: A mission to Europa and the Jupiter System for ESA's Cosmic Vision Programme
NASA Astrophysics Data System (ADS)
Blanc, Michel; Alibert, Yann; André, Nicolas; Atreya, Sushil; Beebe, Reta; Benz, Willy; Bolton, Scott J.; Coradini, Angioletta; Coustenis, Athena; Dehant, Véronique; Dougherty, Michele; Drossart, Pierre; Fujimoto, Masaki; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Kasaba, Yasumasa; Kivelson, Margaret; Khurana, Krishan; Krupp, Norbert; Louarn, Philippe; Lunine, Jonathan; McGrath, Melissa; Mimoun, David; Mousis, Olivier; Oberst, Juergen; Okada, Tatsuaki; Pappalardo, Robert; Prieto-Ballesteros, Olga; Prieur, Daniel; Regnier, Pascal; Roos-Serote, Maarten; Sasaki, Sho; Schubert, Gerald; Sotin, Christophe; Spilker, Tom; Takahashi, Yukihiro; Takashima, Takeshi; Tosi, Federico; Turrini, Diego; van Hoolst, Tim; Zelenyi, Lev
2009-03-01
The exploration of the Jovian System and its fascinating satellite Europa is one of the priorities presented in ESA’s “Cosmic Vision” strategic document. The Jovian System indeed displays many facets. It is a small planetary system in its own right, built-up out of the mixture of gas and icy material that was present in the external region of the solar nebula. Through a complex history of accretion, internal differentiation and dynamic interaction, a very unique satellite system formed, in which three of the four Galilean satellites are locked in the so-called Laplace resonance. The energy and angular momentum they exchange among themselves and with Jupiter contribute to various degrees to the internal heating sources of the satellites. Unique among these satellites, Europa is believed to shelter an ocean between its geodynamically active icy crust and its silicate mantle, one where the main conditions for habitability may be fulfilled. For this very reason, Europa is one of the best candidates for the search for life in our Solar System. So, is Europa really habitable, representing a “habitable zone” in the Jupiter system? To answer this specific question, we need a dedicated mission to Europa. But to understand in a more generic way the habitability conditions around giant planets, we need to go beyond Europa itself and address two more general questions at the scale of the Jupiter system: to what extent is its possible habitability related to the initial conditions and formation scenario of the Jovian satellites? To what extent is it due to the way the Jupiter system works? ESA’s Cosmic Vision programme offers an ideal and timely framework to address these three key questions. Building on the in-depth reconnaissance of the Jupiter System by Galileo (and the Voyager, Ulysses, Cassini and New Horizons fly-by’s) and on the anticipated accomplishments of NASA’s JUNO mission, it is now time to design and fly a new mission which will focus on these
Decoupling the NLO-coupled QED⊗QCD, DGLAP evolution equations, using Laplace transform method
NASA Astrophysics Data System (ADS)
Mottaghizadeh, Marzieh; Eslami, Parvin; Taghavi-Shahri, Fatemeh
2017-05-01
We analytically solved the QED⊗QCD-coupled DGLAP evolution equations at leading order (LO) quantum electrodynamics (QED) and next-to-leading order (NLO) quantum chromodynamics (QCD) approximations, using the Laplace transform method and then computed the proton structure function in terms of the unpolarized parton distribution functions. Our analytical solutions for parton densities are in good agreement with those from CT14QED (1.2952 < Q2 < 1010) (Ref. 6) global parametrizations and APFEL (A PDF Evolution Library) (2 < Q2 < 108) (Ref. 4). We also compared the proton structure function, F2p(x,Q2), with the experimental data released by the ZEUS and H1 collaborations at HERA. There is a nice agreement between them in the range of low and high x and Q2.
Bayesian inference using two-stage Laplace approximation for differential equation models
NASA Astrophysics Data System (ADS)
Dass, Sarat C.; Lee, Jaeyong; Lee, Kyoungjae
2016-11-01
We consider the problem of Bayesian inference for parameters in non-linear regression models whereby the underlying unknown response functions are formed by a set of differential equations. Bayesian methods of inference for unknown parameters rely primarily on the posterior obtained by Bayes rule. For differential equation models, analytic and closed forms for the posterior are not available and one has to resort to approximations. We propose a two-stage Laplace expansion to approximate the marginal likelihood, and hence, the posterior, to obtain an approximate closed form solution. For large sample sizes, the method of inference borrows from non-linear regression theory for maximum likelihood estimates, and is therefore, consistent. Our approach is exact in the limit and does not need the specification of an additional penalty parameter. Examples in this paper include the exponential model and SIR (Susceptible-Infected-Recovered) disease spread model.
Laplace pressure induced droplet generation in micromold for synthesizing monodisperse microspheres.
NASA Astrophysics Data System (ADS)
Choi, Chang-Hyung; Lee, Jinkee; Lee, Chang-Soo
2012-02-01
Microspheres are widely used in applications such MEMS, chemical release systems, optical materials and various biological applications. Here, we report the new micromolding technique for synthesizing spherical monodisperse particles through surface-tension-induced flow. The spherical droplets were prepared using Laplace pressure difference, which is highly depending on geometries of the mold shape, without any pumping system to make flow. We calculated the minimum pressure difference to make the flow moves and form the droplets. It provides a synthetic tool for generating the microspheres using different reaction schemes; UV-polymerization, sol-gel reaction and colloidal assemblies. The monodisperse spherical particles, which are made of various materials, were successfully generated without any surfactant because each droplet can be separately positioned in mold patterns during solidification process.
Laplace-Runge-Lenz vector in quantum mechanics in noncommutative space
Gáliková, Veronika; Kováčik, Samuel; Prešnajder, Peter
2013-12-15
The main point of this paper is to examine a “hidden” dynamical symmetry connected with the conservation of Laplace-Runge-Lenz vector (LRL) in the hydrogen atom problem solved by means of non-commutative quantum mechanics (NCQM). The basic features of NCQM will be introduced to the reader, the key one being the fact that the notion of a point, or a zero distance in the considered configuration space, is abandoned and replaced with a “fuzzy” structure in such a way that the rotational invariance is preserved. The main facts about the conservation of LRL vector in both classical and quantum theory will be reviewed. Finally, we will search for an analogy in the NCQM, provide our results and their comparison with the QM predictions. The key notions we are going to deal with are non-commutative space, Coulomb-Kepler problem, and symmetry.
Numerical determination of the fundamental eigenvalue for the Laplace operator on a spherical domain
NASA Technical Reports Server (NTRS)
Walden, H.
1977-01-01
Methods for obtaining approximate solutions for the fundamental eigenvalue of the Laplace-Beltrami operator (i.e., the membrane eignevalue problem for the vibration equation) on the unit spherical surface are developed. Two types of spherical surface domains are considered: the interior of a spherical triangle, and the exterior of a great circle arc extending for less than pi radians (a spherical surface with a slit). In both cases, zero boundary conditions are imposed. In order to solve the resulting second-order elliptic partial differential equations in two independent variables, a finite difference approximation is employed. The fundamental eigenvalue is approximated by iteration utilizing the power method and point successive overrelaxation. Some numerical results are given and compared, in certain special cases, with analytical solutions to the eigenvalue problem. The significance of the numerical eigenvalue results is discussed in terms of the singularities in the solution of three-dimensional boundary-value problems near a polyhedral corner of the domain.
Reconstructing diffusion ordered NMR spectroscopy by simultaneous inversion of Laplace transform
NASA Astrophysics Data System (ADS)
Yuan, Bin; Ding, Yiming; Kamal, Ghulam M.; Shao, Limin; Zhou, Zhiming; Jiang, Bin; Sun, Peng; Zhang, Xu; Liu, Maili
2017-05-01
2D diffusion-ordered NMR spectroscopy (DOSY) has been widely recognized as a powerful tool for analyzing mixtures and probing inter-molecular interactions in situ. But it is difficult to differentiate molecules with similar diffusion coefficients in presence of overlapped spectra. Its performance is susceptible to the number of chemical components, and usually gets worse when the number of components increases. Here, to alleviate the problem, numerical simultaneous inversion of Laplace transform (SILT) of many related variables is proposed for reconstructing DOSY spectrum (SILT-DOSY). The advantage of the proposed method in comparison to other methods is that it is capable of estimating the number of analytes more accurately and deriving corresponding component spectra, which in turn leads to the more reliable identification of the components.
Origin and Use of the Laplace Distribution in Daily Sunspot Numbers
NASA Astrophysics Data System (ADS)
Noble, P. L.; Wheatland, M. S.
2013-02-01
Recently Pop ( Solar Phys. 276, 351, 2012) identified a Laplace (or double exponential) distribution in the number of days with a given absolute value in the change over a day, in sunspot number, for days on which the sunspot number does change. We show this phenomenological rule has a physical origin attributable to sunspot formation, evolution, and decay, rather than being due to the changes in sunspot number caused by groups rotating onto and off the visible disc. We also demonstrate a simple method to simulate daily sunspot numbers over a solar cycle using the Pop ( Solar Phys. 276, 351, 2012) result, together with a model for the cycle variation in the mean sunspot number. The procedure is applied to three recent solar cycles. We check that the simulated sunspot numbers reproduce the observed distribution of daily changes over those cycles.
NASA Astrophysics Data System (ADS)
Wang, Rong Feng; Mei, Zhong Lei; Yang, Xin Yu; Ma, Xiang; Cui, Tie Jun
2014-04-01
For ideal invisibility cloaks, electromagnetic radiations cannot penetrate through the cloaking shell. However, researchers have suggested that the originally hidden object with a cloaking shell is visible to the outside world when it is covered by an "anticloak." In this paper, we give the first experimental verification of the "anticloak" for the Laplace equation, which requires negative conductivity profiles. The proposed device consists of two layers—the cloak and anticloak, which can work individually or collectively and give rise to different functions. Functionality switching among the invisibility cloak, anticloak, transparent cloak, superscatterer, and illusion is suggested and demonstrated. Based on the circuit theory, we fabricate a switching resistor network with both positive and negative resistors to emulate the cloaking and anticloaking interactions. The switchable cloaking, anticloaking, transparent, superscatterer, and illusion performances are confirmed by the experiments and/or numerical simulations.
Quantification in time-domain diffuse optical tomography using Mellin-Laplace transforms
Zouaoui, Judy; Di Sieno, Laura; Hervé, Lionel; Pifferi, Antonio; Farina, Andrea; Mora, Alberto Dalla; Derouard, Jacques; Dinten, Jean-Marc
2016-01-01
Simulations and phantom measurements are used to evaluate the ability of time-domain diffuse optical tomography using Mellin-Laplace transforms to quantify the absorption perturbation of centimetric objects immersed at depth 1-2 cm in turbid media. We find that the estimated absorption coefficient varies almost linearly with the absorption change in the range of 0-0.15 cm−1 but is underestimated by a factor that depends on the inclusion depth (~2, 3 and 6 for depths of 1.0, 1.5 and 2.0 cm respectively). For larger absorption changes, the variation is sublinear with ~20% decrease for δμa = 0.37 cm−1. By contrast, constraining the absorption change to the actual volume of the inclusion may considerably improve the accuracy and linearity of the reconstructed absorption. PMID:27867736
Transition metals (Ti and Co) in silicon and their complexes with hydrogen: A Laplace DLTS study
NASA Astrophysics Data System (ADS)
Kolkovsky, Vl.; Scheffler, L.; Weber, J.
2014-04-01
The electrical properties of transition metals (TM) in Si were often determined by means of the conventional deep level transient spectroscopy (DLTS) technique. In the present study we demonstrate that the poor resolution of the conventional DLTS technique could lead to the wrong interpretation of the experimental data. On the example of well-known lifetime killers such as titanium and cobalt we show that the dominant defects appeared in samples doped with these impurities were previously wrongly attributed to different charged states of interstitial Ti and substitutional Co. Applying the high-resolution Laplace DLTS technique we re-examine the origin of these defects. Some of these defects will be shown to react with H and shallow acceptors leading to the appearance of new complex defects in the band gap of Si. Their nature will also be discussed in the present paper.
The nonsinglet spin-dependent structure function evolution by Laplace and characteristics methods
Boroun, G. R. E-mail: boroun@razi.ac.ir; Zarrin, S.; Dadfar, S.
2016-03-15
We evaluate the non-singlet spin-dependent structure function g{sub 1}{sup NS} at leading order (LO) and next-to-leading order (NLO) by using the Laplace-transform technique and method of characteristics and also obtain its first moment at NLO. The polarized non-singlet structure function results are compared with the data from HERMES (A. Airapetian et al., Phys. Rev. D 75, 012007 (2007)) and E143 (K. Abe et al. (E143 Collab.), Phys. Rev. D 58, 112003 (1998)) at LO and NLO analyses and the first-moment the result at NLO is compared with the result of the NLO GRSV2000 fit. Considering the solution, this method is valid at low- and large-x regions.
NASA Astrophysics Data System (ADS)
Kholshevnikov, Konstantin V.; Shaidulin, Vakhit Sh.
2016-11-01
The main form of the representation of a gravitational potential V for a celestial body T in outer space is the Laplace series in solid spherical harmonics (R/r)^{n+1}Y_n(θ ,λ ) with R being the radius of the enveloping T sphere. The surface harmonic Y_n satisfies the inequality < Y_nrangle < Cn^{-σ }. The angular brackets mark the maximum of a function's modulus over a unit sphere. For bodies with an irregular structure σ = 5/2 , and this value cannot be increased generally. However, a class of irregular bodies (smooth bodies with peaked mountains) has been found recently in which σ = 3 . In this paper, we will prove the exactness of this estimate, showing that a body belonging to the above class does exist and 0<\\varlimsup n^3< Y_nrangle <∞ for it.
Green's function and image system for the Laplace operator in the prolate spheroidal geometry
NASA Astrophysics Data System (ADS)
Xue, Changfeng; Deng, Shaozhong
2017-01-01
In the present paper, electrostatic image theory is studied for Green's function for the Laplace operator in the case where the fundamental domain is either the exterior or the interior of a prolate spheroid. In either case, an image system is developed to consist of a point image inside the complement of the fundamental domain and an additional symmetric continuous surface image over a confocal prolate spheroid outside the fundamental domain, although the process of calculating such an image system is easier for the exterior than for the interior Green's function. The total charge of the surface image is zero and its centroid is at the origin of the prolate spheroid. In addition, if the source is on the focal axis outside the prolate spheroid, then the image system of the exterior Green's function consists of a point image on the focal axis and a line image on the line segment between the two focal points.
Lu, Dingjie; Xie, Yi Min; Huang, Xiaodong; Zhou, Shiwei; Li, Qing
2015-11-28
Analytical studies on the size effects of a simply-shaped beam fixed at both ends have successfully explained the sudden changes of effective Young's modulus as its diameter decreases below 100 nm. Yet they are invalid for complex nanostructures ubiquitously existing in nature. In accordance with a generalized Young-Laplace equation, one of the representative size effects is transferred to non-uniformly distributed pressure against an external surface due to the imbalance of inward and outward loads. Because the magnitude of pressure depends on the principal curvatures, iterative steps have to be adopted to gradually stabilize the structure in finite element analysis. Computational results are in good agreement with both experiment data and theoretical prediction. Furthermore, the investigation on strengthened and softened Young's modulus for two complex nanostructures demonstrates that the proposed computational method provides a general and effective approach to analyze the size effects for nanostructures in arbitrary shape.
NASA Astrophysics Data System (ADS)
Chanu, Claudia Maria; Degiovanni, Luca; Rastelli, Giovanni
2017-03-01
It is natural to investigate if the quantization of integrable or superintegrable classical Hamiltonian systems is still integrable or superintegrable. We study here this problem in the case of natural Hamiltonians with constants of motion quadratic in the momenta. The procedure of quantization here considered transforms the Hamiltonian into the Laplace-Beltrami operator plus a scalar potential. In order to transform the constants of motion into symmetry operators of the quantum Hamiltonian, additional scalar potentials, known as quantum corrections, must be introduced, depending on the Riemannian structure of the manifold. We give here a complete geometric characterization of the quantum corrections necessary for the case considered. In particular, Stäckel systems are studied in detail. Examples in conformally and non-conformally flat manifolds are given.
Infinite-Dimensional Schur-Weyl Duality and the Coxeter-Laplace Operator
NASA Astrophysics Data System (ADS)
Tsilevich, N. V.; Vershik, A. M.
2014-05-01
We extend the classical Schur-Weyl duality between representations of the groups and to the case of and the infinite symmetric group . Our construction is based on a "dynamic," or inductive, scheme of Schur-Weyl dualities. It leads to a new class of representations of the infinite symmetric group, which has not appeared earlier. We describe these representations and, in particular, find their spectral types with respect to the Gelfand-Tsetlin algebra. The main example of such a representation acts in an incomplete infinite tensor product. As an important application, we consider the weak limit of the so-called Coxeter-Laplace operator, which is essentially the Hamiltonian of the XXX Heisenberg model, in these representations.
NASA Astrophysics Data System (ADS)
Telyakovskii, D. S.
2017-01-01
In this paper we weaken the sufficient conditions of harmonicity for functions of two variables. I.I. Privalov had shown that a continuous function that satisfies the Laplace equation in each point of the domain is harmonic. For function of two variables the Privalov’s condition on continuity can be weakened. G.P. Tolstov replaced the continuity condition by the boundness condition, later the author had shown that summability is sufficient. At the same time summability condition can not be weakened substantially. In this paper, while we keep the summability condition, we provide the sufficient condition for harmonicity of the functions, that satisfy less restricted condition than the Laplace equation in all points of the domain. We assume that arbitrary close to any point ζ there exists a collection of four nodes for which a difference relation of Schwartz type for the Laplace equation can be made arbitrary small by the absolute value. Nodes are the ends of two mutually perpendicular segments, that intersect at point ζ. We need to impose a certain weakened continuous assumption on function itself, in case of function that satisfy the traditional Laplace condition this continuity condition follows from the existence of the partial derivatives.
NASA Astrophysics Data System (ADS)
Mehrabi Pari, Sharareh; Javidan, Kurosh; Taghavi Shahri, Fatemeh
2016-05-01
The "Laplace Transform Method" is used to solve the Fokker-Plank equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.
ERIC Educational Resources Information Center
Iqbal, M.
2002-01-01
In this paper we have converted the Laplace transform into an integral equation of the first kind of convolution type, which is an ill-posed problem, and used a statistical regularization method to solve it. The method is applied to three examples. It gives a good approximation to the true solution and compares well with the method given by…
ERIC Educational Resources Information Center
Iqbal, M.
2002-01-01
In this paper we have converted the Laplace transform into an integral equation of the first kind of convolution type, which is an ill-posed problem, and used a statistical regularization method to solve it. The method is applied to three examples. It gives a good approximation to the true solution and compares well with the method given by…
NASA Astrophysics Data System (ADS)
Malezan, A.; Tomal, A.; Antoniassi, M.; Watanabe, P. C. A.; Albino, L. D.; Poletti, M. E.
2015-11-01
In this work, a spectral reconstruction methodology for diagnostic X-ray, using Laplace inverse transform of the attenuation, was successfully applied to dental X-ray equipments. The attenuation curves of 8 commercially available dental X-ray equipment, from 3 different manufactures (Siemens, Gnatus and Dabi Atlante), were obtained by using an ionization chamber and high purity aluminium filters, while the kVp was obtained with a specific meter. A computational routine was implemented in order to adjust a model function, whose inverse Laplace transform is analytically known, to the attenuation curve. This methodology was validated by comparing the reconstructed and the measured (using semiconductor detector of cadmium telluride) spectra of a given dental X-ray unit. The spectral reconstruction showed the Dabi Atlante equipments generating similar shape spectra. This is a desirable feature from clinic standpoint because it produces similar levels of image quality and dose. We observed that equipments from Siemens and Gnatus generate significantly different spectra, suggesting that, for a given operating protocol, these units will present different levels of image quality and dose. This fact claims for the necessity of individualized operating protocols that maximize image quality and dose. The proposed methodology is suitable to perform a spectral reconstruction of dental X-ray equipments from the simple measurements of attenuation curve and kVp. The simplified experimental apparatus and the low level of technical difficulty make this methodology accessible to a broad range of users. The knowledge of the spectral distribution can help in the development of operating protocols that maximize image quality and dose.
Validity of the "Laplace Swindle" in Calculation of Giant-Planet Gravity Fields
NASA Astrophysics Data System (ADS)
Hubbard, William B.
2014-11-01
Jupiter and Saturn have large rotation-induced distortions, providing an opportunity to constrain interior structure via precise measurement of external gravity. Anticipated high-precision gravity measurements close to the surfaces of Jupiter (Juno spacecraft) and Saturn (Cassini spacecraft), possibly detecting zonal harmonics to J10 and beyond, will place unprecedented requirements on gravitational modeling via the theory of figures (TOF). It is not widely appreciated that the traditional TOF employs a formally nonconvergent expansion attributed to Laplace. This suspect expansion is intimately related to the standard zonal harmonic (J-coefficient) expansion of the external gravity potential. It can be shown (Hubbard, Schubert, Kong, and Zhang: Icarus, in press) that both Jupiter and Saturn are in the domain where Laplace's "swindle" works exactly, or at least as well as necessary. More highly-distorted objects such as rapidly spinning asteroids may not be in this domain, however. I present a numerical test for the validity and precision of TOF via polar "audit points". I extend the audit-point test to objects rotating differentially on cylinders, obtaining zonal harmonics to J20 and beyond. Models with only low-order differential rotation do not exhibit dramatic effects in the shape of the zonal harmonic spectrum. However, a model with Jupiter-like zonal winds exhibits a break in the zonal harmonic spectrum above about J10, and generally follows the more shallow Kaula power rule at higher orders. This confirms an earlier result obtained by a different method (Hubbard: Icarus 137, 357-359, 1999).
Laplace domain automatic data assimilation of contaminant transport using a Wireless Sensor Network
NASA Astrophysics Data System (ADS)
Barnhart, K.; Illangasekare, T. H.
2011-12-01
Emerging in situ sensors and distributed network technologies have the potential to monitor dynamic hydrological and environmental processes more effectively than traditional monitoring and data acquisition techniques by sampling at greater spatial and temporal resolutions. In particular, Wireless Sensor Networks, the combination of low-power telemetry and energy-harvesting with miniaturized sensors, could play a large role in monitoring the environment on nature's time scale. Since sensor networks supply data with little or no delay, applications exist where automatic or real-time assimilation of this data would be useful, for example during smart remediation procedures where tracking of the plume response will reinforce real-time decisions. As a foray into this new data context, we consider the estimation of hydraulic conductivity when incorporating subsurface plume concentration data. Current practice optimizes the model in the time domain, which is often slow and overly sensitive to data anomalies. Instead, we perform model inversion in Laplace space and are able to do so because data gathered using new technologies can be sampled densely in time. An intermediate-scale synthetic aquifer is used to illustrate the developed technique. Data collection and model (re-)optimization are automatic. Electric conductivity values of passing sodium bromide plumes are sent through a wireless sensor network, stored in a database, scrubbed and passed to a modeling server which transforms the data and assimilates it into a Laplace domain model. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000
Computing the Distribution of Pareto Sums Using Laplace Transformation and Stehfest Inversion
NASA Astrophysics Data System (ADS)
Harris, C. K.; Bourne, S. J.
2017-05-01
that is shared by the sum of an arbitrary number of such variables. The technique involves applying the Laplace transform to the normalized sum (which is simply the product of the Laplace transforms of the densities of the individual variables, with a suitable scaling of the Laplace variable), and then inverting it numerically using the Gaver-Stehfest algorithm. After validating the method using a number of test cases, it was applied to address the distribution of total seismic moment, and the quantiles computed for various numbers of seismic events were compared with those obtained in the literature using Monte Carlo simulation. Excellent agreement was obtained. As an application, the method was applied to the evolution of total seismic moment released by tremors due to gas production in the Groningen gas field in the northeastern Netherlands. The speed, accuracy and ease of implementation of the method allows the development of accurate correlations for constraining statistical seismological models using, for example, the maximum-likelihood method. It should also be of value in other natural processes governed by Pareto distributions with exponent less than unity.
NASA Astrophysics Data System (ADS)
Tønning, Erik; Polders, Daniel; Callaghan, Paul T.; Engelsen, Søren B.
2007-09-01
This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T2- D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T2- D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T2- D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D = 3 × 10 -12 m 2 s -1 and T2 = 180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D = 10 -9 m 2 s -1, T2 = 10 ms and D = 3 × 10 -13 m 2 s -1, T2 = 13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it
Tripathi, Rajnee; Mishra, Hradyesh Kumar
2016-01-01
In this communication, we describe the Homotopy Perturbation Method with Laplace Transform (LT-HPM), which is used to solve the Lane-Emden type differential equations. It's very difficult to solve numerically the Lane-Emden types of the differential equation. Here we implemented this method for two linear homogeneous, two linear nonhomogeneous, and four nonlinear homogeneous Lane-Emden type differential equations and use their appropriate comparisons with exact solutions. In the current study, some examples are better than other existing methods with their nearer results in the form of power series. The Laplace transform used to accelerate the convergence of power series and the results are shown in the tables and graphs which have good agreement with the other existing method in the literature. The results show that LT-HPM is very effective and easy to implement.
NASA Astrophysics Data System (ADS)
Gomez, Raul; Gomez, Sandra; Marquina, Ma. Luisa
2004-03-01
Most of the Mechanics and Mathematics for Physicists books ignore the problem of obtaining the isochrone (tautochrone) curve in the uniform gravitational field of Earth. A noticeable exception is Arfken's^1 book, which uses the Laplace transform formalism and the convolution theorem to resolve the problem. Through an adequate change of variable, the Laplace transform can be extended in such a way as to be able to apply the convolution theorem. The tautachrone problem for an arbitrary potential energy function can then be resolved. Moreover, the inverse problem of finding the potential function associated with a given arbitrary trajectory can also be established. It is worth noting that the same results can also be obtained using a less known formalism of fractional derivatives ^2. ^1G. Arfken, Mathematical Methods for Physicists. Academic Press (1970) pp 713. ^2Eduardo Flores. The tautochrone under arbitrary potentials using fractional derivatives, Am. J. Phys. 67 (1999) 718-722.
Use of the augmented Young-Laplace equation to model equilibrium and evaporating extended menisci
DasGupta, S.; Schonberg, J.A.; Kim, I.Y.; Wayner, P.C.Jr. )
1993-05-01
The generic importance of fluid flow and change-of-phase heat transfer in the contact line region of an extended meniscus has led to theoretical and experimental research on the details of these transport processes. Numerical solutions of equilibrium and nonequilibrium models based on the augmented Young-Laplace equation were successfully used to evaluate experimental data for an extended meniscus. The data for the equilibrium and nonequilibrium meniscus profiles were obtained optically using ellipsometry and image processing interferometry. A Taylor series expansion of the fourth-order nonlinear transport model was used to obtain the extremely sensitive initial conditions at the interline. The solid-liquid-vapor Hamaker constants for the systems were obtained from the experimental data. The consistency of the data was demonstrated by using the combining rules to calculate the unknown value of the Hamaker constant for the experimental substrate. The sensitivity of the meniscus profile to small changes in the environment was demonstrated. Both temperature and intermolecular forces need to be included in modeling transport processes in the contact line region because the chemical potential is a function of both temperature and pressure.
Wang, Gang; Zhang, Xiaofeng; Su, Qingtang; Shi, Jie; Caselli, Richard J.; Wang, Yalin
2015-01-01
Cortical thickness estimation in magnetic resonance imaging (MRI) is an important technique for research on brain development and neurodegenerative diseases. This paper presents a heat kernel based cortical thickness estimation algorithm, which is driven by the graph spectrum and the heat kernel theory, to capture the grey matter geometry information from the in vivo brain magnetic resonance (MR) images. First, we construct a tetrahedral mesh that matches the MR images and reflects the inherent geometric characteristics. Second, the harmonic field is computed by the volumetric Laplace-Beltrami operator and the direction of the steamline is obtained by tracing the maximum heat transfer probability based on the heat kernel diffusion. Thereby we can calculate the cortical thickness information between the point on the pial and white matter surfaces. The new method relies on intrinsic brain geometry structure and the computation is robust and accurate. To validate our algorithm, we apply it to study the thickness differences associated with Alzheimer’s disease (AD) and mild cognitive impairment (MCI) on the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset. Our preliminary experimental results on 151 subjects (51 AD, 45 MCI, 55 controls) show that the new algorithm may successfully detect statistically significant difference among patients of AD, MCI and healthy control subjects. Our computational framework is efficient and very general. It has the potential to be used for thickness estimation on any biological structures with clearly defined inner and outer surfaces. PMID:25700360
Mulligan, Vikram Khipple; Hadley, Kevin Charles; Chakrabartty, Avijit
2012-02-01
Kinetic experiments provide much information about protein folding mechanisms. Time-resolved signals are often best described by expressions with many exponential terms, but this hinders the extraction of rate constants by nonlinear least squares (NLS) fitting. Numerical inverse Laplace transformation, which converts a time-resolved dataset into a spectrum of amplitudes as a function of rate constant, allows easy estimation of the rate constants, amplitudes, and number of processes underlying the data. Here, we present a Tikhonov regularization-based method that converts a dataset into a rate spectrum, subject to regularization constraints, without requiring an iterative search of parameter space. This allows more rapid generation of rate spectra as well as analysis of datasets too noisy to process by existing iterative search algorithms. This method's simplicity also permits highly objective, largely automatic analysis with minimal human guidance. We show that this regularization method reproduces results previously obtained by NLS fitting and that it is effective for analyzing datasets too complex for traditional fitting methods. This method's reliability and speed, as well as its potential for objective, model-free analysis, make it extremely useful as a first step in analysis of complicated noisy datasets and an excellent guide for subsequent NLS analysis. Copyright © 2011 Elsevier Inc. All rights reserved.
NASA Astrophysics Data System (ADS)
Choi, Chang-Hyung; Kim, Jongmin; Kang, Sung-Min; Lee, Jinkee; Lee, Chang-Soo
2013-03-01
Monodisperse microspheres play critical roles in many applications such as micro-electromechanical systems (MEMS), chemical release systems, optical materials and various biological applications. Although microfluidic systems have been developed for producing monodisperse microspheres, it still definitely requires pressure driven flow for continuous fluid injection as well as use of surfactant to achieve their uniformity. Here, we present a novel molding method that generates monodisperse microspheres through surface-tension-induced flow. Two immiscible fluids that consist of photocurable monomer and hydrophobic oil are sequentially applied onto the mold. The mold geometry results in Laplace pressure induced droplet formation, and these droplets formed are individually localized into each micromold. Photopolymerization of the droplets allow for the formation of polymer microspheres with narrow size distribution (CV =1.9%). We obtain the microspheres with diameter ranging from 20 to 300 μm by modulating mold dimensions. We provide a synthesis method to produce microspheres in micromolds for various reaction schemes: UV-polymerization, sol-gel reactions and colloidal assemblies.
Metric Optimization for Surface Analysis in the Laplace-Beltrami Embedding Space
Lai, Rongjie; Wang, Danny J.J.; Pelletier, Daniel; Mohr, David; Sicotte, Nancy; Toga, Arthur W.
2014-01-01
In this paper we present a novel approach for the intrinsic mapping of anatomical surfaces and its application in brain mapping research. Using the Laplace-Beltrami eigen-system, we represent each surface with an isometry invariant embedding in a high dimensional space. The key idea in our system is that we realize surface deformation in the embedding space via the iterative optimization of a conformal metric without explicitly perturbing the surface or its embedding. By minimizing a distance measure in the embedding space with metric optimization, our method generates a conformal map directly between surfaces with highly uniform metric distortion and the ability of aligning salient geometric features. Besides pairwise surface maps, we also extend the metric optimization approach for group-wise atlas construction and multi-atlas cortical label fusion. In experimental results, we demonstrate the robustness and generality of our method by applying it to map both cortical and hippocampal surfaces in population studies. For cortical labeling, our method achieves excellent performance in a cross-validation experiment with 40 manually labeled surfaces, and successfully models localized brain development in a pediatric study of 80 subjects. For hippocampal mapping, our method produces much more significant results than two popular tools on a multiple sclerosis study of 109 subjects. PMID:24686245
Nature of the X(5568) — A critical Laplace sum rule analysis at N2LO
NASA Astrophysics Data System (ADS)
Albuquerque, R.; Narison, S.; Rabemananjara, A.; Rabetiarivony, D.
2016-06-01
We scrutinize recent QCD spectral sum rules (QSSR) results to lowest order (LO) predicting the masses of the BK molecule and (su)(bd¯) four-quark states. We improve these results by adding NLO and N2LO corrections to the PT contributions giving a more precise meaning on the b-quark mass definition used in the analysis. We extract our optimal predictions using Laplace sum rule (LSR) within the standard stability criteria versus the changes of the external free parameters (τ-sum rule variable, tc continuum threshold and subtraction constant μ). The smallness of the higher order PT corrections justifies (a posteriori) the LO order results ⊕ the uses of the ambiguous heavy quark mass to that order. However, our predicted spectra in the range (5173 ˜ 5226) MeV, summarized in Table 7, for exotic hadrons built with four different flavors (buds), do not support some previous interpretations of the D0 candidate,1 X(5568), as a pure molecule or a four-quark state. If experimentally confirmed, it could result from their mixing with an angle: sin 2𝜃 ≈ 0.15. One can also scan the region (2327 ˜ 2444) MeV (where the Ds0∗(2317) might be a good candidate) and the one (5173 ˜ 5226) MeV for detecting these (cuds) and (buds) unmixed exotic hadrons (if any) via, eventually, their radiative or π+hadrons decays.
Emergence of Laplace therapeutics: declaring an end to end-stage heart failure.
Mehra, Mandeep R; Uber, Patricia A
2002-01-01
A large number of chronic heart failure patients escape from the benefits of neurohormonal blockade only to transit into a discouragingly miserable state of what the physician often refers to as end-stage heart failure. Conceptually, the designation of end-stage as a description of a clinical scenario implies pessimism concerning recourse to a therapeutic avenue. A variety of surgical therapeutic techniques that take advantage of the law of Laplace, designed to effectively restore the cardiac shape from a spherical, mechanically inefficient pump to a more elliptical, structurally sound organ are now being employed. Additionally, the field of mechanical device implantation is surging ahead at a rapid pace. The weight of evidence regarding mechanical unloading using assist devices suggests that hemodynamic restoration is accompanied by regression of cellular hypertrophy, normalization of the neuroendocrine axis, improved expression of contractile proteins, enhanced cellular respiratory control, and decreases in markers of apoptosis and cellular stress. Thus, these lines of data point toward discarding the notion of end-stage heart failure. We are at a new crossroad in our quest to tackle chronic heart failure. It is our contention that the use of antiremodeling strategies, including device approaches, will soon signal the end of end-stage heart failure.
Laplace's equation and the Dirichlet-Neumann map in multiply connected domains
NASA Technical Reports Server (NTRS)
Greenbaum, A.; Greengard, L.; Mcfadden, G. B.
1993-01-01
A variety of problems in material science and fluid dynamics require the solution of Laplace's equation in multiply connected domains. Integral equation methods are natural candidates for such problems, since they discretize the boundary alone, require no special effort for free boundaries, and achieve superalgebraic convergence rates on sufficiently smooth domains in two space dimensions, regardless of shape. Current integral equation methods for the Dirichlet problem, however, require the solution of M independent problems of dimension N, where M is the number of boundary components and N is the total number of points in the discretization. In this paper, we present a new boundary integral equation approach, valid for both interior and exterior problems, which requires the solution of a single linear system of dimension N + M. We solve this system by making use of an iterative method (GMRES) combined with the last multipole method for the rapid calculation of the necessary matrix vector products. For a two-dimensional system with 200 components and 100 points on each boundary, we gain a speedup of a factor of 100 from the new analytic formulation and a factor of 50 from the fast multipole method. The resulting scheme brings large scale calculations in extremely complex domains within practical reach.
Modeling of Sunspot Numbers by a Modified Binary Mixture of Laplace Distribution Functions
NASA Astrophysics Data System (ADS)
Sabarinath, A.; Anilkumar, A. K.
2008-07-01
This paper presents a new approach for describing the shape of 11-year sunspot cycles by considering the monthly averaged values. This paper also brings out a prediction model based on the analysis of 22 sunspot cycles from the year 1749 onward. It is found that the shape of the sunspot cycles with monthly averaged values can be described by a functional form of modified binary mixture of Laplace density functions, modified suitably by introducing two additional parameters in the standard functional form. The six parameters, namely two locations, two scales, and two area parameters, characterize this model. The nature of the estimated parameters for the sunspot cycles from 1749 onward has been analyzed and finally we arrived at a sufficient set of the parameters for the proposed model. It is seen that this model picks up the sunspot peaks more closely than any other model without losing the match at other places at the same time. The goodness of fit for the proposed model is also computed with the Hathaway Wilson Reichmann overline{χ} measure, which shows, on average, that the fitted model passes within 0.47 standard deviations of the actual averaged monthly sunspot numbers.
Wang, Gang; Zhang, Xiaofeng; Su, Qingtang; Shi, Jie; Caselli, Richard J; Wang, Yalin
2015-05-01
Cortical thickness estimation in magnetic resonance imaging (MRI) is an important technique for research on brain development and neurodegenerative diseases. This paper presents a heat kernel based cortical thickness estimation algorithm, which is driven by the graph spectrum and the heat kernel theory, to capture the gray matter geometry information from the in vivo brain magnetic resonance (MR) images. First, we construct a tetrahedral mesh that matches the MR images and reflects the inherent geometric characteristics. Second, the harmonic field is computed by the volumetric Laplace-Beltrami operator and the direction of the steamline is obtained by tracing the maximum heat transfer probability based on the heat kernel diffusion. Thereby we can calculate the cortical thickness information between the point on the pial and white matter surfaces. The new method relies on intrinsic brain geometry structure and the computation is robust and accurate. To validate our algorithm, we apply it to study the thickness differences associated with Alzheimer's disease (AD) and mild cognitive impairment (MCI) on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. Our preliminary experimental results on 151 subjects (51 AD, 45 MCI, 55 controls) show that the new algorithm may successfully detect statistically significant difference among patients of AD, MCI and healthy control subjects. Our computational framework is efficient and very general. It has the potential to be used for thickness estimation on any biological structures with clearly defined inner and outer surfaces.
NASA Astrophysics Data System (ADS)
Fatalov, V. R.
2017-06-01
We prove a theorem on the exact asymptotic relations of large deviations of the Bogoliubov measure in the L p norm for p = 4, 6, 8, 10 with p > p 0, where p 0 = 2+4 π 2/ β 2 ω 2 is a threshold value, β > 0 is the inverse temperature, and ω > 0 is the natural frequency of the harmonic oscillator. For the study, we use the Laplace method in function spaces for Gaussian measures.
NASA Technical Reports Server (NTRS)
Mccoy, M. J.
1980-01-01
Various finite difference techniques used to solve Laplace's equation are compared. Curvilinear coordinate systems are used on two dimensional regions with irregular boundaries, specifically, regions around circles and airfoils. Truncation errors are analyzed for three different finite difference methods. The false boundary method and two point and three point extrapolation schemes, used when having the Neumann boundary condition are considered and the effects of spacing and nonorthogonality in the coordinate systems are studied.
Jäntschi, Lorentz; Bálint, Donatella; Bolboacă, Sorana D
2016-01-01
Multiple linear regression analysis is widely used to link an outcome with predictors for better understanding of the behaviour of the outcome of interest. Usually, under the assumption that the errors follow a normal distribution, the coefficients of the model are estimated by minimizing the sum of squared deviations. A new approach based on maximum likelihood estimation is proposed for finding the coefficients on linear models with two predictors without any constrictive assumptions on the distribution of the errors. The algorithm was developed, implemented, and tested as proof-of-concept using fourteen sets of compounds by investigating the link between activity/property (as outcome) and structural feature information incorporated by molecular descriptors (as predictors). The results on real data demonstrated that in all investigated cases the power of the error is significantly different by the convenient value of two when the Gauss-Laplace distribution was used to relax the constrictive assumption of the normal distribution of the error. Therefore, the Gauss-Laplace distribution of the error could not be rejected while the hypothesis that the power of the error from Gauss-Laplace distribution is normal distributed also failed to be rejected.
Jäntschi, Lorentz
2016-01-01
Multiple linear regression analysis is widely used to link an outcome with predictors for better understanding of the behaviour of the outcome of interest. Usually, under the assumption that the errors follow a normal distribution, the coefficients of the model are estimated by minimizing the sum of squared deviations. A new approach based on maximum likelihood estimation is proposed for finding the coefficients on linear models with two predictors without any constrictive assumptions on the distribution of the errors. The algorithm was developed, implemented, and tested as proof-of-concept using fourteen sets of compounds by investigating the link between activity/property (as outcome) and structural feature information incorporated by molecular descriptors (as predictors). The results on real data demonstrated that in all investigated cases the power of the error is significantly different by the convenient value of two when the Gauss-Laplace distribution was used to relax the constrictive assumption of the normal distribution of the error. Therefore, the Gauss-Laplace distribution of the error could not be rejected while the hypothesis that the power of the error from Gauss-Laplace distribution is normal distributed also failed to be rejected. PMID:28090215
A boundary integral algorithm for the Laplace Dirichlet-Neumann mixed eigenvalue problem
NASA Astrophysics Data System (ADS)
Akhmetgaliyev, Eldar; Bruno, Oscar P.; Nigam, Nilima
2015-10-01
We present a novel integral-equation algorithm for evaluation of Zaremba eigenvalues and eigenfunctions, that is, eigenvalues and eigenfunctions of the Laplace operator with mixed Dirichlet-Neumann boundary conditions; of course, (slight modifications of) our algorithms are also applicable to the pure Dirichlet and Neumann eigenproblems. Expressing the eigenfunctions by means of an ansatz based on the single layer boundary operator, the Zaremba eigenproblem is transformed into a nonlinear equation for the eigenvalue μ. For smooth domains the singular structure at Dirichlet-Neumann junctions is incorporated as part of our corresponding numerical algorithm-which otherwise relies on use of the cosine change of variables, trigonometric polynomials and, to avoid the Gibbs phenomenon that would arise from the solution singularities, the Fourier Continuation method (FC). The resulting numerical algorithm converges with high order accuracy without recourse to use of meshes finer than those resulting from the cosine transformation. For non-smooth (Lipschitz) domains, in turn, an alternative algorithm is presented which achieves high-order accuracy on the basis of graded meshes. In either case, smooth or Lipschitz boundary, eigenvalues are evaluated by searching for zero minimal singular values of a suitably stabilized discrete version of the single layer operator mentioned above. (The stabilization technique is used to enable robust non-local zero searches.) The resulting methods, which are fast and highly accurate for high- and low-frequencies alike, can solve extremely challenging two-dimensional Dirichlet, Neumann and Zaremba eigenproblems with high accuracies in short computing times-enabling, in particular, evaluation of thousands of eigenvalues and corresponding eigenfunctions for a given smooth or non-smooth geometry with nearly full double-precision accuracy.
An empirically derived three-dimensional Laplace resonance in the Gliese 876 planetary system
NASA Astrophysics Data System (ADS)
Nelson, Benjamin E.; Robertson, Paul M.; Payne, Matthew J.; Pritchard, Seth M.; Deck, Katherine M.; Ford, Eric B.; Wright, Jason T.; Isaacson, Howard T.
2016-01-01
We report constraints on the three-dimensional orbital architecture for all four planets known to orbit the nearby M dwarf Gliese 876 based solely on Doppler measurements and demanding long-term orbital stability. Our data set incorporates publicly available radial velocities taken with the ELODIE and CORALIE spectrographs, High Accuracy Radial velocity Planet Searcher (HARPS), and Keck HIgh Resolution Echelle Spectrometer (HIRES) as well as previously unpublished HIRES velocities. We first quantitatively assess the validity of the planets thought to orbit GJ 876 by computing the Bayes factors for a variety of different coplanar models using an importance sampling algorithm. We find that a four-planet model is preferred over a three-planet model. Next, we apply a Newtonian Markov chain Monte Carlo algorithm to perform a Bayesian analysis of the planet masses and orbits using an N-body model in three-dimensional space. Based on the radial velocities alone, we find that a 99 per cent credible interval provides upper limits on the mutual inclinations for the three resonant planets (Φcb < 6.20° for the {c} and {b} pair and Φbe < 28.5° for the {b} and {e} pair). Subsequent dynamical integrations of our posterior sample find that the GJ 876 planets must be roughly coplanar (Φcb < 2.60° and Φbe < 7.87°, suggesting that the amount of planet-planet scattering in the system has been low. We investigate the distribution of the respective resonant arguments of each planet pair and find that at least one argument for each planet pair and the Laplace argument librate. The libration amplitudes in our three-dimensional orbital model support the idea of the outer three planets having undergone significant past disc migration.
Rivera, Eugenio J.; Laughlin, Gregory; Vogt, Steven S.; Meschiari, Stefano; Haghighipour, Nader
2010-08-10
Continued radial velocity (RV) monitoring of the nearby M4V red dwarf star GJ 876 with Keck/High Resolution Echelle Spectrograph has revealed the presence of a Uranus-mass fourth planetary companion in the system. The new planet has a mean period of P{sub e} = 126.6 days (over the 12.6-year baseline of the RV observations), and a minimum mass of m{sub e} sin i{sub e} = 12.9 {+-} 1.7 M {sub +}. The detection of the new planet has been enabled by significant improvements to our RV data set for GJ 876. The data have been augmented by 36 new high-precision measurements taken over the past five years. In addition, the precision of all of the Doppler measurements have been significantly improved by the incorporation of a high signal-to-noise template spectrum for GJ 876 into the analysis pipeline. Implementation of the new template spectrum improves the internal rms errors for the velocity measurements taken during 1998-2005 from 4.1 m s{sup -1} to 2.5 m s{sup -1}. Self-consistent, N-body fits to the RV data set show that the four-planet system has an invariable plane with an inclination relative to the plane of the sky of i = 59.{sup 0}5. The fit is not significantly improved by the introduction of a mutual inclination between the planets 'b' and 'c', but the new data do confirm a non-zero eccentricity, e{sub d} = 0.207 {+-} 0.055 for the innermost planet, 'd'. In our best-fit coplanar model, the mass of the new component is m{sub e} = 14.6 {+-} 1.7 M {sub +}. Our best-fitting model places the new planet in a three-body resonance with the previously known giant planets (which have mean periods of P{sub c} = 30.4 and P{sub b} = 61.1 days). The critical argument, {psi}{sub Laplace} = {lambda} {sub c} - 3{lambda} {sub b} + 2{lambda} {sub e}, for the Laplace resonance librates with an amplitude of {Delta}{psi}{sub Laplace} = 40{sup 0} {+-} 13{sup 0} about {psi}{sub Laplace} = 0{sup 0}. Numerical integration indicates that the four-planet system is stable for at least a
NASA Astrophysics Data System (ADS)
Helmich-Paris, Benjamin; Knecht, Stefan
2017-06-01
In the present article, we show how to formulate the partially contracted n-electron valence second-order perturbation theory (NEVPT2) energies in the atomic and active molecular orbital basis by employing the Laplace transformation of orbital-energy denominators (OEDs). As atomic-orbital (AO) basis functions are inherently localized and the number of active orbitals is comparatively small, our formulation is particularly suited for a linearly scaling NEVPT2 implementation. In our formulation, there are two kinds of NEVPT2 energy contributions, which differ in the number of active orbitals in the two-electron integrals involved. Those involving integrals with either no or a single active orbital can be formulated completely in the AO basis as single-reference second-order Møller-Plesset perturbation theory and benefit from sparse active pseudo-density matrices—particularly if the active molecular orbitals are localized only in parts of a molecule. Conversely, energy contributions involving integrals with either two or three active orbitals can be obtained from Coulomb and exchange matrices generalized for pairs of active orbitals. Moreover, we demonstrate that Laplace-transformed partially contracted NEVPT2 is nothing less than time-dependent NEVPT2 [A. Y. Sokolov and G. K.-L. Chan, J. Chem. Phys. 144, 064102 (2016)] iff the all-active intermediates are computed with the internal-contraction approximation. Furthermore, we show that for multi-reference perturbation theories it is particularly challenging to find optimal parameters of the numerical Laplace transformation as the fit range may vary among the 8 different OEDs by many orders of magnitude. Selecting the number of quadrature points for each OED separately according to an accuracy-based criterion allows us to control the errors in the NEVPT2 energies reliably.
An Empirically Derived Three-Dimensional Laplace Resonance in the GJ 876 Planetary System
NASA Astrophysics Data System (ADS)
Nelson, Benjamin Earl; Robertson, Paul; Pritchard, Seth
2015-08-01
We report constraints on the three-dimensional orbital architecture for all four planets known to orbit the nearby M dwarf Gliese 876 (=GJ 876) based solely on Doppler measurements and demanding long-term orbital stability. Our dataset incorporates publicly available radial velocities taken with the ELODIE and CORALIE spectrographs, HARPS, and Keck HIRES as well as previously unpublished HIRES RVs. We first quantitatively assess the validity of the planets thought to orbit GJ 876 by computing the Bayes factors for a variety of different coplanar models using an importance sampling algorithm. We confirm that a four-planet model is indeed preferred over a three-planet model. Next, we apply a Newtonian MCMC algorithm (RUN DMC, B. Nelson et al. 2014) to perform a Bayesian analysis of the planet masses and orbits using an n-body model that allows each planet to take on its own orbit in three-dimensional space. Based on the radial velocities alone, the mutual inclinations for the outer three resonant planets are constrained to Φcb = 2.8±1.71.3 degrees for the "c" and "b" pair and Φbe = 10.3±6.35.1 degrees for the "b" and "e" pair. We integrate the equations of motion of a sample of initial conditions drawn from our posterior for 107 years. We identify dynamically unstable models and find that the GJ 876 planets must be roughly coplanar (Φcb = 1.41±0.620.57 degrees) and (Φbe = 3.9±2.01.9 degrees), indicating the amount of planet-planet scattering in the system has been low. We investigate the distribution of the respective resonant arguments of each planet pair and find that at least one resonant argument for each planet pair and the Laplace argument librate. The libration amplitudes in our three-dimensional orbital model supports the idea of the outer-three planets having undergone significant past disk migration.
NASA Astrophysics Data System (ADS)
Sansottera, Marco; Libert, A.
2013-05-01
Abstract (2,250 Maximum Characters): In this work, we study the secular dynamics of exoplanetary systems consisting of two coplanar planets. In particular, we investigate the effects of the proximity to a mean motion resonance on the secular behavior of the planets. In order to obtain a good description of the secular dynamics, a straightforward method is to include in the unperturbed Hamiltonian the average of the perturbation over the fast angles; this is the so-called approximation at order one in the masses. However, if the system is near a mean motion resonance, the frequencies of the quasi-periodic flow given by this Hamiltonian are quite different from the true ones. Therefore we look for an approximation of the secular Hamiltonian up to order two in the masses, removing the main perturbation depending on the fast angles via a Kolmogorov-like normalization step. The approximation of lowest order in the eccentricities of the secular Hamiltonian is essentially the one considered in the Lagrange-Laplace theory. Following a quite standard procedure, we construct a high order Birkhoff normal form for the Hamiltonian using the Lie series method. Considering the Hamiltonian in non-resonant Birkhoff normal form, the equations of motion take a very simple form, being function of the actions only. So, using the secular frequencies that are easily computed, the long term motion of the planets can be easily integrated analytically. By comparing the semi-analytical results based on the secular approximation, with the dynamics of the complete system, we can better understand whether resonant contributions dominate the evolution of the planets or not. This leads to a simple criterion to discriminate between three categories of systems: : (i) secular systems (HD 11964, HD 74156, HD 134987, HD 163607, HD 12661 and HD 147018); (ii) systems near a mean-motion resonance (HD 11506, HD 177830, HD 9446, HD 169830 and $\\upsilon$ Andromedae); (iii) systems really close to or in a
Laplace-Pressure Actuation of Liquid Metal Devices For Reconfigurable Electromagnetics
NASA Astrophysics Data System (ADS)
Cumby, Brad Lee
it is resilient and shapeable to allow for reconfigurability. In this dissertation, first background information is given on the existing technology for reconfigurable microwave devices and the basic principles that these mechanisms are based upon. Then a new reconfigurable method is introduced that utilizes Laplace pressure. Materials that are associated with using liquid metals are discussed and an overall systematic view is given to provide a set of proof of concepts that are more applied and understandable by electronic designers and engineers. Finally a novel approach to making essential measurements of liquid metal microwave devices is devised and discussed. This dissertation encompasses a complete device design from materials used for fabrication, fabrication methods and measurement processes to provide a knowledge base for designing liquid metal microwave devices.
NASA Astrophysics Data System (ADS)
Adimurthi; Karthik, A.; Giacomoni, Jacques
2016-06-01
Let n ≥ 2 and Ω ⊂Rn be a bounded domain. Then by Trudinger-Moser embedding, W01,n (Ω) is embedded in an Orlicz space consisting of exponential functions. Consider the corresponding semilinear n-Laplace equation with critical or sub-critical exponential nonlinearity in a ball B (R) with dirichlet boundary condition. In this paper, we prove that under suitable growth conditions on the nonlinearity, there exists an γ0 > 0, and a corresponding R0 (γ0) > 0 such that for all 0 < R
A Comparison of the Laplace Distribution with an Empirical Model of D062 Demand in Lead Time.
1981-09-01
D062) are based on formu- las originally developed by Presutti and Trepp (1970). These authors consider the problem of determining order quantities and...Presutti and Trepp + -.. .5 Ayb*,OMl ; r4g that demand in a lead time is normally distrib- uted. Howeve;I they then utilize the Laplace distribution to A...i.e. k denotes the number of standard deviations that the demand value x exceeds the expected demand in a lead time. Given (1), - Presutti and Trepp
NASA Astrophysics Data System (ADS)
Studenikin, S. A.; Golego, Nickolay; Cocivera, Michael
1998-11-01
Slow relaxation of the photoconductivity over a period of days was studied in polycrystalline ZnO and TiO2 films prepared by spray pyrolysis. The phenomenon is described by a model involving deep sensitizing hole traps in the forbidden gap. The trap state distribution based on this model was calculated using an improved Laplace transform method. For ZnO and TiO2 films, the density of states was shown to have a peak-like distribution with a maximum near the lower third of the energy gap.
Characterization of defects created in Cz and epitaxial Si doped with Ga or B using Laplace-DLTS
NASA Astrophysics Data System (ADS)
Nyamhere, Cloud; Deenapanray, P. N. K.; Auret, F. D.; Farlow, F. C.
2006-04-01
We have measured the electrical and annealing properties of defects created in epitaxial and Czochralski-grown Si doped with either B or Ga by electron irradiation using both conventional and Laplace deep level transient spectroscopy (L)-DLTS. With L-DLTS, we have been able to resolve several defects that cannot be resolved using conventional DLTS. L-DLTS provides a new avenue to study defect introduction rates and annealing kinetics in B- and Ga-doped Si. The isochronal annealing behaviour of the defects was also investigated.
NASA Astrophysics Data System (ADS)
Orazov, Issabek; Besbaev, Gani A.
2016-12-01
In the present work we investigate a nonlocal boundary problem for the Laplace equation in a half-disk, with opposite flows at the part of the boundary. The difference of this problem is the impossibility of direct applying of the Fourier method (separation of variables). Because the corresponding spectral problem for the ordinary differential equation has the system of eigenfunctions not forming a basis. A special system of functions based on these eigenfunctions is constructed. This system has already formed the basis. This fact is used for solving the nonlocal boundary problem. The existence and the uniqueness of classical solution of the problem are proved.
NASA Astrophysics Data System (ADS)
Nejad, S. Mohammad Moosavi; Khanpour, Hamzeh; Tehrani, S. Atashbar; Mahdavi, Mahdi
2016-10-01
We present a detailed QCD analysis of nucleon structure functions x F3(x ,Q2) , based on Laplace transforms and the Jacobi polynomials approach. The analysis corresponds to the next-to-leading order and next-to-next-to-leading order approximations of perturbative QCD. The Laplace transform technique, as an exact analytical solution, is used for the solution of nonsinglet Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations at low- and large-x values. The extracted results are used as input to obtain the x and Q2 evolution of x F3(x ,Q2) structure functions using the Jacobi polynomials approach. In our work, the values of the typical QCD scale ΛMS¯ (nf) and the strong coupling constant αs(MZ2) are determined for four quark flavors (nf=4 ) as well. A careful estimation of the uncertainties shall be performed using the Hessian method for the valence-quark distributions, originating from the experimental errors. We compare our valence-quark parton distribution functions sets with those of other collaborations, in particular with the CT14, MMHT14, and NNPDF sets, which are contemporary with the present analysis. The obtained results from the analysis are in good agreement with those from the literature.
NASA Astrophysics Data System (ADS)
Jafari, Nasrin; Azhari, Mojtaba
2016-11-01
In this paper, the stability analysis of moderately thick time-dependent viscoelastic plates with various shapes is studied using the Laplace-Carson transformation and simple hp cloud meshless method. The shear effect of the plate is described by the first order shear deformation theory. The mechanical properties of the materials are supposed to be linear viscoelastic based on the constant bulk modulus. The displacement field is assumed to be the product of two functions, one being a function of geometrical parameters and the other a known exponential function of time. The simple hp cloud method is used for discretization which is based on Kronecker-delta properties. Thus, the essential boundary conditions can be imposed directly. A numerical investigation is made by employing the inverse of Laplace-Carson transformation. The time history of buckling coefficients of viscoelastic plates of various shapes with different boundary conditions is considered. Moreover, a number of numerical results are presented to study the effect of thickness, aspect ratio, different boundary conditions, and various shapes on the time history of buckling coefficients of the viscoelastic plate.
Schmitz, Gunnar; Hättig, Christof
2016-12-21
We present an implementation of pair natural orbital coupled cluster singles and doubles with perturbative triples, PNO-CCSD(T), which avoids the quasi-canonical triples approximation (T0) where couplings due to off-diagonal Fock matrix elements are neglected. A numerical Laplace transformation of the canonical expression for the perturbative (T) triples correction is used to avoid an I/O and storage bottleneck for the triples amplitudes. Results for a test set of reaction energies show that only very few Laplace grid points are needed to obtain converged energy differences and that PNO-CCSD(T) is a more robust approximation than PNO-CCSD(T0) with a reduced mean absolute deviation from canonical CCSD(T) results. We combine the PNO-based (T) triples correction with the explicitly correlated PNO-CCSD(F12*) method and investigate the use of specialized F12-PNOs in the conventional triples correction. We find that no significant additional errors are introduced and that PNO-CCSD(F12*)(T) can be applied in a black box manner.
NASA Astrophysics Data System (ADS)
Jafari, Nasrin; Azhari, Mojtaba
2017-08-01
In this paper, the stability analysis of moderately thick time-dependent viscoelastic plates with various shapes is studied using the Laplace-Carson transformation and simple hp cloud meshless method. The shear effect of the plate is described by the first order shear deformation theory. The mechanical properties of the materials are supposed to be linear viscoelastic based on the constant bulk modulus. The displacement field is assumed to be the product of two functions, one being a function of geometrical parameters and the other a known exponential function of time. The simple hp cloud method is used for discretization which is based on Kronecker-delta properties. Thus, the essential boundary conditions can be imposed directly. A numerical investigation is made by employing the inverse of Laplace-Carson transformation. The time history of buckling coefficients of viscoelastic plates of various shapes with different boundary conditions is considered. Moreover, a number of numerical results are presented to study the effect of thickness, aspect ratio, different boundary conditions, and various shapes on the time history of buckling coefficients of the viscoelastic plate.
NASA Astrophysics Data System (ADS)
Schmitz, Gunnar; Hättig, Christof
2016-12-01
We present an implementation of pair natural orbital coupled cluster singles and doubles with perturbative triples, PNO-CCSD(T), which avoids the quasi-canonical triples approximation (T0) where couplings due to off-diagonal Fock matrix elements are neglected. A numerical Laplace transformation of the canonical expression for the perturbative (T) triples correction is used to avoid an I/O and storage bottleneck for the triples amplitudes. Results for a test set of reaction energies show that only very few Laplace grid points are needed to obtain converged energy differences and that PNO-CCSD(T) is a more robust approximation than PNO-CCSD(T0) with a reduced mean absolute deviation from canonical CCSD(T) results. We combine the PNO-based (T) triples correction with the explicitly correlated PNO-CCSD(F12*) method and investigate the use of specialized F12-PNOs in the conventional triples correction. We find that no significant additional errors are introduced and that PNO-CCSD(F12*)(T) can be applied in a black box manner.
NASA Astrophysics Data System (ADS)
Petrov, P.; Newman, G. A.
2010-12-01
Quantitative imaging of the subsurface objects is essential part of modern geophysical technology important in oil and gas exploration and wide-range engineering applications. A significant advancement in developing a robust, high resolution imaging technology is concerned with using the different geophysical measurements (gravity, EM and seismic) sense the subsurface structure. A joint image of the subsurface geophysical attributes (velocity, electrical conductivity and density) requires the consistent treatment of the different geophysical data (electromagnetic and seismic) due to their differing physical nature - diffusive and attenuated propagation of electromagnetic energy and nonlinear, multiple scattering wave propagation of seismic energy. Recent progress has been reported in the solution of this problem by reducing the complexity of seismic wave field. Works formed by Shin and Cha (2009 and 2008) suggests that low-pass filtering the seismic trace via Laplace-Fourier transformation can be an effective approach for obtaining seismic data that has similar spatial resolution to EM data. The effect of Laplace- Fourier transformation on the low-pass filtered trace changes the modeling of the seismic wave field from multi-wave propagation to diffusion. The key benefit of transformation is that diffusive wave-field inversion works well for both data sets seismic (Shin and Cha, 2008) and electromagnetic (Commer and Newman 2008, Newman et al., 2010). Moreover the different data sets can also be matched for similar and consistent resolution. Finally, the low pass seismic image is also an excellent choice for a starting model when analyzing the entire seismic waveform to recover the high spatial frequency components of the seismic image; its reflectivity (Shin and Cha, 2009). Without a good starting model full waveform seismic imaging and migration can encounter serious difficulties. To produce seismic wave fields consistent for joint imaging in the Laplace
NASA Astrophysics Data System (ADS)
Petrov, P.; Newman, G. A.
2011-12-01
Recent developments in high resolution imaging technology of subsurface objects involves a combination of different geophysical measurements (gravity, EM and seismic). A joint image of the subsurface geophysical attributes (velocity, electrical conductivity and density) requires the consistent treatment of the different geophysical data due to their differing physical nature. For example, in conducting media, which is typical of the Earth's interior, EM energy propagation is defined by a diffusive mechanism and may be characterized by two specific length scales: wavelength and skin depth. However, the propagation of seismic signals is a multiwave process and is characterized by a set of wavelengths. Thus, to consistently treat seismic and electromagnetic data an additional length scale is needed for seismic data that does not directly depend on a wavelength and describes a diffusive process, similar to EM wave propagation in the subsurface. Works by Brown et al.(2005), Shin and Cha(2008), and Shin and Ha(2008) suggest that an artificial damping of seismic wave fields via Laplace-Fourier transformation can be an effective approach to obtain a seismic data that have similar spatial resolution to EM data. The key benefit of such transformation is that diffusive wave-field inversion works well for both data sets: seismic (Brown et al.,2005; Shin and Cha,2008) and electromagnetic (Commer and Newman,2008; Newman et al.,2010). With the recent interest in the Laplace-Fourier domain full waveform inversion, 3D fourth and second-order finite-difference schemes for modeling of seismic wave propagation have been developed (Petrov and Newman, 2010). Incorporation of attenuation and anisotropy into a velocity model is a necessary step for a more realistic description of subsurface media. Here we consider the extension of our method which includes attenuation and VTI anisotropy. Our approach is based on the integro-interpolation technique for velocity-stress formulation. Seven
Beer, Matthias; Ochsenfeld, Christian
2008-06-14
A density matrix-based Laplace reformulation of coupled-perturbed self-consistent field (CPSCF) theory is presented. It allows a direct, instead of iterative, solution for the integral-independent part of the density matrix-based CPSCF (D-CPSCF) equations [J. Kussmann and C. Ochsenfeld, J. Chem. Phys. 127, 054103 (2007)]. In this way, the matrix-multiplication overhead compared to molecular orbital-based solutions is reduced to a minimum, while at the same time, the linear-scaling behavior of D-CPSCF theory is preserved. The present Laplace-based equation solver is expected to be of general applicability.
NASA Astrophysics Data System (ADS)
López-Yela, A.; Pérez-Pardo, J. M.
2017-10-01
A numerical scheme to compute the spectrum of a large class of self-adjoint extensions of the Laplace-Beltrami operator on manifolds with boundary in any dimension is presented. The algorithm is based on the characterisation of a large class of self-adjoint extensions of Laplace-Beltrami operators in terms of their associated quadratic forms. The convergence of the scheme is proved. A two-dimensional version of the algorithm is implemented effectively and several numerical examples are computed showing that the algorithm treats in a unified way a wide variety of boundary conditions.
NASA Astrophysics Data System (ADS)
Filippi, P. J. T.
1983-11-01
In has been shown that the sound field reflected by the plane boundary of a layered ground can always be described by a specularly reflected wave, and layer potentials. Despite its generality, this representation is not quite suitable for numerical computation. Dealing with a very simple case, Weyl, and later on Ingard and Thomasson, proposed a representation of the solution in which the layer potential terms are replaced by the sum of surface wave and a Laplace type integral. Such an integral is very convenient for numerical purposes. In this paper, it is shown that this kind of representation can be obtained for a very wide class of sound propagation problems above or within layered media: a half-space bounded by a locally reacting surface, a finite layer of porous medium, a porous medium with depth-varying porosity, a thin elastic plate; wave propagation in shallow water with an impedance bottom. Many other applications could be developed.
NASA Technical Reports Server (NTRS)
Tiffany, S. H.; Adams, W. M., Jr.
1984-01-01
A technique which employs both linear and nonlinear methods in a multilevel optimization structure to best approximate generalized unsteady aerodynamic forces for arbitrary motion is described. Optimum selection of free parameters is made in a rational function approximation of the aerodynamic forces in the Laplace domain such that a best fit is obtained, in a least squares sense, to tabular data for purely oscillatory motion. The multilevel structure and the corresponding formulation of the objective models are presented which separate the reduction of the fit error into linear and nonlinear problems, thus enabling the use of linear methods where practical. Certain equality and inequality constraints that may be imposed are identified; a brief description of the nongradient, nonlinear optimizer which is used is given; and results which illustrate application of the method are presented.
Filobello-Nino, Uriel; Vazquez-Leal, Hector; Cervantes-Perez, Juan; Benhammouda, Brahim; Perez-Sesma, Agustin; Hernandez-Martinez, Luis; Jimenez-Fernandez, Victor Manuel; Herrera-May, Agustin Leobardo; Pereyra-Diaz, Domitilo; Marin-Hernandez, Antonio; Huerta Chua, Jesus
2014-01-01
This article proposes Laplace Transform Homotopy Perturbation Method (LT-HPM) to find an approximate solution for the problem of an axisymmetric Newtonian fluid squeezed between two large parallel plates. After comparing figures between approximate and exact solutions, we will see that the proposed solutions besides of handy, are highly accurate and therefore LT-HPM is extremely efficient.
Darwich, R.; Mani, A. A.
2010-08-15
New substructures of H4 and H5 hole traps have been revealed using Laplace deep-level transient spectroscopy. Our measurements show that the hole traps H4 and H5 can have at least three components for each. Moreover, the activation energies are deduced and the microscopic nature of these substructures is discussed.
Stefenelli, Mario; Todt, Juraj; Riedl, Angelika; Ecker, Werner; Müller, Thomas; Daniel, Rostislav; Burghammer, Manfred; Keckes, Jozef
2013-10-01
Novel scanning synchrotron cross-sectional nanobeam and conventional laboratory as well as synchrotron Laplace X-ray diffraction methods are used to characterize residual stresses in exemplary 11.5 µm-thick TiN coatings. Both real and Laplace space approaches reveal a homogeneous tensile stress state and a very pronounced compressive stress gradient in as-deposited and blasted coatings, respectively. The unique capabilities of the cross-sectional approach operating with a beam size of 100 nm in diameter allow the analysis of stress variation with sub-micrometre resolution at arbitrary depths and the correlation of the stress evolution with the local coating microstructure. Finally, advantages and disadvantages of both approaches are extensively discussed.
NASA Astrophysics Data System (ADS)
Kjærgaard, Thomas
2017-01-01
The divide-expand-consolidate resolution of the identity second-order Møller-Plesset perturbation (DEC-RI-MP2) theory method introduced in Baudin et al. [J. Chem. Phys. 144, 054102 (2016)] is significantly improved by introducing the Laplace transform of the orbital energy denominator in order to construct the double amplitudes directly in the local basis. Furthermore, this paper introduces the auxiliary reduction procedure, which reduces the set of the auxiliary functions employed in the individual fragments. The resulting Laplace transformed divide-expand-consolidate resolution of the identity second-order Møller-Plesset perturbation method is applied to the insulin molecule where we obtain a factor 9.5 speedup compared to the DEC-RI-MP2 method.
Shen, Changqing; Liu, Fang; Wang, Dong; Zhang, Ao; Kong, Fanrang; Tse, Peter W.
2013-01-01
The condition of locomotive bearings, which are essential components in trains, is crucial to train safety. The Doppler effect significantly distorts acoustic signals during high movement speeds, substantially increasing the difficulty of monitoring locomotive bearings online. In this study, a new Doppler transient model based on the acoustic theory and the Laplace wavelet is presented for the identification of fault-related impact intervals embedded in acoustic signals. An envelope spectrum correlation assessment is conducted between the transient model and the real fault signal in the frequency domain to optimize the model parameters. The proposed method can identify the parameters used for simulated transients (periods in simulated transients) from acoustic signals. Thus, localized bearing faults can be detected successfully based on identified parameters, particularly period intervals. The performance of the proposed method is tested on a simulated signal suffering from the Doppler effect. Besides, the proposed method is used to analyze real acoustic signals of locomotive bearings with inner race and outer race faults, respectively. The results confirm that the periods between the transients, which represent locomotive bearing fault characteristics, can be detected successfully. PMID:24253191
Xia, Yan; Hofmann, Hannes; Dennerlein, Frank; Mueller, Kerstin; Schwemmer, Chris; Bauer, Sebastian; Chintalapani, Gouthami; Chinnadurai, Ponraj; Hornegger, Joachim; Maier, Andreas
2014-03-01
It is known that a reduction of the field-of-view in 3-D X-ray imaging is proportional to a reduction in radiation dose. The resulting truncation, however, is incompatible with conventional reconstruction algorithms. Recently, a novel method for region of interest reconstruction that uses neither prior knowledge nor extrapolation has been published, named approximated truncation robust algorithm for computed tomography (ATRACT). It is based on a decomposition of the standard ramp filter into a 2-D Laplace filtering and a 2-D Radon-based residual filtering step. In this paper, we present two variants of the original ATRACT. One is based on expressing the residual filter as an efficient 2-D convolution with an analytically derived kernel. The second variant is to apply ATRACT in 1-D to further reduce computational complexity. The proposed algorithms were evaluated by using a reconstruction benchmark, as well as two clinical data sets. The results are encouraging since the proposed algorithms achieve a speed-up factor of up to 245 compared to the 2-D Radon-based ATRACT. Reconstructions of high accuracy are obtained, e.g., even real-data reconstruction in the presence of severe truncation achieve a relative root mean square error of as little as 0.92% with respect to nontruncated data.
NASA Astrophysics Data System (ADS)
Holota, Petr; Nesvadba, Otakar
2015-04-01
In this paper the reciprocal distance is used for generating Galerkin's approximations in the weak solution of Neumann's problem that has an important role in Earth's gravity field studies. The reciprocal distance has a natural tie to the fundamental solution of Laplace's partial differential equation and in the paper it is represented by means of an expansion into a series of oblate spheroidal harmonics. Subsequently, the gradient vector of the reciprocal distance is constructed. In the computation of its components the expansion mentioned above is employed. The paper then focuses on the scalar product of reciprocal distance gradients in two different points and in particular on a series representation of a volume integral of the scalar product spread over an unbounded domain given by the exterior of an oblate spheroid (oblate ellipsoid of revolution). The integral yields the entries of Galerkin's matrix. The numerical interpretation of all the expansions used as well as the respective software implementation within the OpenCL framework is treated, which concerns also a numerical evaluation of Legendre functions of a real and an imaginary argument. In parallel an approximate closed formula expressing the entries of Galerkin's matrix (with an accuracy up to terms multiplied by the square of numerical eccentricity) is derived for convenience and comparison. The paper is added extensive numerical examples that illustrate the approach applied and demonstrate the accuracy of the derived formulas. Aspects related to practical applications are discussed.
NASA Astrophysics Data System (ADS)
Wie, Bong; Ahn, Jaemyung
2016-09-01
This paper is concerned with a classical yet still mystifying problem regarding multiple roots of the angles-only initial orbit determination (IOD) polynomial equations of Lagrange, Laplace, and Gauss of the form: f(x) = x 8+a x 6+b x 3+c=0 where a,c<0. A possibility of multiple non-spurious roots of this 8th order polynomial equation with b>0 has been extensively treated in the celestial mechanics literature. However, the literature on applied astrodynamics has not treated this multiple-root issue in detail, and not many specific numerical examples with multiple roots are available in the literature. In this paper, a very simple method of determining the correct root from two or three non-spurious roots is presented, which doesn't utilize any a priori knowledge and/or additional observations of the object. The proposed method exploits a simple approximate polynomial equation of the form: g(x) = x 8+a x 6=0. An approximate polynomial equation, either g(x) = x 8+c=0 or g(x) = x 8+a x 6=x 6(x 2+a) = 0, can also be used for quickly estimating an initial guess of the correct root.
NASA Astrophysics Data System (ADS)
Miftahurrohmah, Brina; Iriawan, Nur; Fithriasari, Kartika
2017-06-01
Stocks are known as the financial instruments traded in the capital market which have a high level of risk. Their risks are indicated by their uncertainty of their return which have to be accepted by investors in the future. The higher the risk to be faced, the higher the return would be gained. Therefore, the measurements need to be made against the risk. Value at Risk (VaR) as the most popular risk measurement method, is frequently ignore when the pattern of return is not uni-modal Normal. The calculation of the risks using VaR method with the Normal Mixture Autoregressive (MNAR) approach has been considered. This paper proposes VaR method couple with the Mixture Laplace Autoregressive (MLAR) that would be implemented for analysing the first three biggest capitalization Islamic stock return in JII, namely PT. Astra International Tbk (ASII), PT. Telekomunikasi Indonesia Tbk (TLMK), and PT. Unilever Indonesia Tbk (UNVR). Parameter estimation is performed by employing Bayesian Markov Chain Monte Carlo (MCMC) approaches.
NASA Astrophysics Data System (ADS)
Wie, Bong; Ahn, Jaemyung
2017-03-01
This paper is concerned with a classical yet still mystifying problem regarding multiple roots of the angles-only initial orbit determination (IOD) polynomial equations of Lagrange, Laplace, and Gauss of the form: f( x) = x 8+ a x 6+ b x 3+ c=0 where a, c<0. A possibility of multiple non-spurious roots of this 8th order polynomial equation with b>0 has been extensively treated in the celestial mechanics literature. However, the literature on applied astrodynamics has not treated this multiple-root issue in detail, and not many specific numerical examples with multiple roots are available in the literature. In this paper, a very simple method of determining the correct root from two or three non-spurious roots is presented, which doesn't utilize any a priori knowledge and/or additional observations of the object. The proposed method exploits a simple approximate polynomial equation of the form: g( x) = x 8+ a x 6=0. An approximate polynomial equation, either g( x) = x 8+ c=0 or g( x) = x 8+ a x 6= x 6( x 2+ a) = 0, can also be used for quickly estimating an initial guess of the correct root.
NASA Astrophysics Data System (ADS)
Helmich-Paris, Benjamin; Repisky, Michal; Visscher, Lucas
2016-07-01
We present a formulation of Laplace-transformed atomic orbital-based second-order Møller-Plesset perturbation theory (MP2) energies for two-component Hamiltonians in the Kramers-restricted formalism. This low-order scaling technique can be used to enable correlated relativistic calculations for large molecular systems. We show that the working equations to compute the relativistic MP2 energy differ by merely a change of algebra (quaternion instead of real) from their non-relativistic counterparts. With a proof-of-principle implementation we study the effect of the nuclear charge on the magnitude of half-transformed integrals and show that for light elements spin-free and spin-orbit MP2 energies are almost identical. Furthermore, we investigate the effect of separation of charge distributions on the Coulomb and exchange energy contributions, which show the same long-range decay with the inter-electronic/atomic distance as for non-relativistic MP2. A linearly scaling implementation is possible if the proper distance behavior is introduced to the quaternion Schwarz-type estimates as for non-relativistic MP2.
NASA Technical Reports Server (NTRS)
Walden, H.
1974-01-01
Methods for obtaining approximate solutions for the fundamental eigenvalue of the Laplace-Beltrami operator (also referred to as the membrane eigenvalue problem for the vibration equation) on the unit spherical surface are developed. Two specific types of spherical surface domains are considered: (1) the interior of a spherical triangle, i.e., the region bounded by arcs of three great circles, and (2) the exterior of a great circle arc extending for less than pi radians on the sphere (a spherical surface with a slit). In both cases, zero boundary conditions are imposed. In order to solve the resulting second-order elliptic partial differential equations in two independent variables, a finite difference approximation is derived. The symmetric (generally five-point) finite difference equations that develop are written in matrix form and then solved by the iterative method of point successive overrelaxation. Upon convergence of this iterative method, the fundamental eigenvalue is approximated by iteration utilizing the power method as applied to the finite Rayleigh quotient.
Heavy-Light Exotics from QCD Laplace Sum Rule at N2LO in the chiral limit
NASA Astrophysics Data System (ADS)
Albuquerque, R. M.; Fanomezana, F.; Narison, S.; Rabemananjara, A.; Rabetiarivony, D.; Randriamanatrika, G.
2017-01-01
These talks review and summarize our results in [1, 2] on XYZ-like spectra obtained from QCD Laplace Sum Rule in the chiral limit at next-to-next-leading order (N2LO) of perturbation theory (PT) and including leading order (LO) contributions of dimensions d ≤ 6 - 8 non-perturbative condensates. We conclude that the observed XZ states are good candidates for 1+ and 0+ molecules or / and four-quark states while the predictions for 1- and 0- states are about 1.5 GeV above the Yc,b experimental candidates and hadronic thresholds. We (numerically) find that these exotic molecules couple weakly to the corresponding interpolating currents than ordinary D, B heavy-light mesons while we observe that these couplings decrease faster [ 1 /mb3/2 (resp. 1 /mb) for the 1+, 0+ (resp. 1-, 0-) states] than 1 /mb1/2. results do not also confirm the existence of the X(5568) state in agreement with LHCb findings.
Riebler, Andrea; Held, Leonhard
2017-05-01
The projection of age-stratified cancer incidence and mortality rates is of great interest due to demographic changes, but also therapeutical and diagnostic developments. Bayesian age-period-cohort (APC) models are well suited for the analysis of such data, but are not yet used in routine practice of epidemiologists. Reasons may include that Bayesian APC models have been criticized to produce too wide prediction intervals. Furthermore, the fitting of Bayesian APC models is usually done using Markov chain Monte Carlo (MCMC), which introduces complex convergence concerns and may be subject to additional technical problems. In this paper we address both concerns, developing efficient MCMC-free software for routine use in epidemiological applications. We apply Bayesian APC models to annual lung cancer data for females in five different countries, previously analyzed in the literature. To assess the predictive quality, we omit the observations from the last 10 years and compare the projections with the actual observed data based on the absolute error and the continuous ranked probability score. Further, we assess calibration of the one-step-ahead predictive distributions. In our application, the probabilistic forecasts obtained by the Bayesian APC model are well calibrated and not too wide. A comparison to projections obtained by a generalized Lee-Carter model is also given. The methodology is implemented in the user-friendly R-package BAPC using integrated nested Laplace approximations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
NASA Astrophysics Data System (ADS)
Geslain, A.; Raetz, S.; Hiraiwa, M.; Abi Ghanem, M.; Wallen, S. P.; Khanolkar, A.; Boechler, N.; Laurent, J.; Prada, C.; Duclos, A.; Leclaire, P.; Groby, J.-P.
2016-10-01
We present a method for the recovery of complex wavenumber information via spatial Laplace transforms of spatiotemporal wave propagation measurements. The method aids in the analysis of acoustic attenuation phenomena and is applied in three different scenarios: (i) Lamb-like modes in air-saturated porous materials in the low kHz regime, where the method enables the recovery of viscoelastic parameters; (ii) Lamb modes in a Duralumin plate in the MHz regime, where the method demonstrates the effect of leakage on the splitting of the forward S1 and backward S2 modes around the Zero-Group Velocity point; and (iii) surface acoustic waves in a two-dimensional microscale granular crystal adhered to a substrate near 100 MHz, where the method reveals the complex wavenumbers for an out-of-plane translational and two in-plane translational-rotational resonances. This method provides physical insight into each system and serves as a unique tool for analyzing spatiotemporal measurements of propagating waves.
Bakhos, Tania; Saibaba, Arvind K.; Kitanidis, Peter K.
2015-10-15
We consider the problem of estimating parameters in large-scale weakly nonlinear inverse problems for which the underlying governing equations is a linear, time-dependent, parabolic partial differential equation. A major challenge in solving these inverse problems using Newton-type methods is the computational cost associated with solving the forward problem and with repeated construction of the Jacobian, which represents the sensitivity of the measurements to the unknown parameters. Forming the Jacobian can be prohibitively expensive because it requires repeated solutions of the forward and adjoint time-dependent parabolic partial differential equations corresponding to multiple sources and receivers. We propose an efficient method based on a Laplace transform-based exponential time integrator combined with a flexible Krylov subspace approach to solve the resulting shifted systems of equations efficiently. Our proposed solver speeds up the computation of the forward and adjoint problems, thus yielding significant speedup in total inversion time. We consider an application from Transient Hydraulic Tomography (THT), which is an imaging technique to estimate hydraulic parameters related to the subsurface from pressure measurements obtained by a series of pumping tests. The algorithms discussed are applied to a synthetic example taken from THT to demonstrate the resulting computational gains of this proposed method.
Helmich-Paris, Benjamin; Repisky, Michal; Visscher, Lucas
2016-07-07
We present a formulation of Laplace-transformed atomic orbital-based second-order Møller-Plesset perturbation theory (MP2) energies for two-component Hamiltonians in the Kramers-restricted formalism. This low-order scaling technique can be used to enable correlated relativistic calculations for large molecular systems. We show that the working equations to compute the relativistic MP2 energy differ by merely a change of algebra (quaternion instead of real) from their non-relativistic counterparts. With a proof-of-principle implementation we study the effect of the nuclear charge on the magnitude of half-transformed integrals and show that for light elements spin-free and spin-orbit MP2 energies are almost identical. Furthermore, we investigate the effect of separation of charge distributions on the Coulomb and exchange energy contributions, which show the same long-range decay with the inter-electronic/atomic distance as for non-relativistic MP2. A linearly scaling implementation is possible if the proper distance behavior is introduced to the quaternion Schwarz-type estimates as for non-relativistic MP2.
ERIC Educational Resources Information Center
Grimm, C. A.
This document contains two units that examine integral transforms and series expansions. In the first module, the user is expected to learn how to use the unified method presented to obtain Laplace transforms, Fourier transforms, complex Fourier series, real Fourier series, and half-range sine series for given piecewise continuous functions. In…
Costanzo, Francesco; Brasseur, James G
2015-03-01
There are strong medical motivations to measure changes in material properties of tubular organs, in vivo and in vitro. The current approach estimates hoop stress from intraluminal pressure using the Laplace law and identifies 'elastic modulus' as the slope of a curve fitted hoop stress plotted against strain data. We show that this procedure is fundamentally flawed because muscle and other soft tissue are closely incompressible, so that the total stress includes a volume-preserving material-dependent hydrostatic response that invalidates the method. Furthermore, we show that the Laplace law incorrectly estimates total stress in biological vessels. However, the great need to estimate elastic modulus leads us to develop an alternative practical method, based on shear stress-strain, i.e. insensitive to nonelastic response from incompressibility, but that uses the same measurement data as the current (incorrect) method. The individual material parameters in the underlying (unknown) constitutive relation combine into an effective shear modulus that is a true measure of elastic response, unaffected by incompressibility and without reference to the Laplace law. Furthermore, our effective shear modulus is determined directly as a function of deformation, rather than as the slope of a fitted curve. We validate our method by comparing effective shear moduli against exact shear moduli for four theoretical materials with different degrees of nonlinearity and numbers of material parameters. To further demonstrate applicability, we reanalyse an in vivo study with our new method and show that it resolves an inconsistent change in modulus with the current method.
Barboza, Gia Elise
2016-04-01
This study quantifies the spatiotemporal risk of child abuse and neglect in Los Angeles at the census tract level over a recent 4-year period, identifies areas of increased risk, and evaluates the role of structural disadvantage in substantiated child maltreatment referrals. Child maltreatment data on 83,379 child maltreatment cases in 1,678 census tracts spanning 2006-2009 were obtained from the Los Angeles County Department of Children and Family Services. Substantiated referral counts were analyzed across census tracts with Bayesian hierarchical spatial models using integrated nested Laplace approximations. Results showed that the unadjusted yearly rate of child abuse and neglect held fairly steady over the study period decreasing by only 2.57%. However, the temporal term in the spatiotemporal model reflected a downward trend beginning in 2007. High rates of abuse and neglect were predicted by several neighborhood-level measures of structural burden. Every 1-unit decrease in the social vulnerability index reduced the risk of child abuse and neglect by 98.3% (95% CrI = 1.869-2.1042) while every 1-unit increase in the Black-White dissimilarity index decreased child abuse and neglect risk by 70.6%. The interaction of these variables demonstrated the protective effect of racial heterogeneity in socially vulnerable neighborhoods. No such effect was found in neighborhoods characterized by low levels of vulnerability. Population-based child abuse and neglect prevention and intervention efforts should be aided by the characteristics of neighborhoods that demonstrate strong spatial patterns even after accounting for the role of race and place.
An augmented Young-Laplace model of an evaporating meniscus in a micro-channel with high heat flux
NASA Technical Reports Server (NTRS)
Wayner, P. C., Jr.; Plawsky, J.; Schonberg, J. A.; Dasgupta, S.
1993-01-01
High flux evaporations from a steady meniscus formed in a 2 micron channel is modeled using the augmented Young-Laplace equation. The heat flux is found to be a function of the long range van der Waals dispersion force which represents interfacial conditions between heptane and various substrates. Heat fluxes of (1.3-1.6) x 10(exp 6) W/m(exp 2) based on the width of the channel are obtained for heptane completely wetting the substrate at 100 C. Small channels are used to obtain these large fluxes. Even though the real contact angle is 0 deg, the apparent contact angle is found to vary between 24.8 deg and 25.6 deg. The apparent contact angle, which represents viscous losses near the contact line, has a large effect on the heat flow rate because of its effect on capillary suction and the area of the meniscus. The interfacial heat flux is modeled using kinetic theory for the evaporation rate. The superheated state depends on the temperature and the pressure of the liquid phase. The liquid pressure differs from the pressure of the vapor phase due to capillarity and long range van der Waals dispersion forces which are relevant in the ultra think film formed at the leading edge of the meniscus. Important pressure gradients in the thin film cause a substantial apparent contact angle for a complete wetting system. The temperature of the liquid is related to the evaporation rate and to the substrate temperature through the steady heat conduction equation. Conduction in the liquid phase is calculated using finite element analysis except in the vicinity of the thin film. A lubrication theory solution for the thin film is combined with the finite element analysis by the method of matched asymptotic expansions.
Blumberg, L.N.
1992-03-01
The authors have analyzed simulated magnetic measurements data for the SXLS bending magnet in a plane perpendicular to the reference axis at the magnet midpoint by fitting the data to an expansion solution of the 3-dimensional Laplace equation in curvilinear coordinates as proposed by Brown and Servranckx. The method of least squares is used to evaluate the expansion coefficients and their uncertainties, and compared to results from an FFT fit of 128 simulated data points on a 12-mm radius circle about the reference axis. They find that the FFT method gives smaller coefficient uncertainties that the Least Squares method when the data are within similar areas. The Least Squares method compares more favorably when a larger number of data points are used within a rectangular area of 30-mm vertical by 60-mm horizontal--perhaps the largest area within the 35-mm x 75-mm vacuum chamber for which data could be obtained. For a grid with 0.5-mm spacing within the 30 x 60 mm area the Least Squares fit gives much smaller uncertainties than the FFT. They are therefore in the favorable position of having two methods which can determine the multipole coefficients to much better accuracy than the tolerances specified to General Dynamics. The FFT method may be preferable since it requires only one Hall probe rather than the four envisioned for the least squares grid data. However least squares can attain better accuracy with fewer probe movements. The time factor in acquiring the data will likely be the determining factor in choice of method. They should further explore least squares analysis of a Fourier expansion of data on a circle or arc of a circle since that method gives coefficient uncertainties without need for multiple independent sets of data as needed by the FFT method.
NASA Astrophysics Data System (ADS)
Guan, Wen; Li, Li; Jin, Weiqi; Qiu, Su; Zou, Yan
2015-10-01
Extreme-Low-Light CMOS has been widely applied in the field of night-vision as a new type of solid image sensor. But if the illumination in the scene has drastic changes or the illumination is too strong, Extreme-Low-Light CMOS can't both clearly present the high-light scene and low-light region. According to the partial saturation problem in the field of night-vision, a HDR image fusion algorithm based on the Laplace Pyramid was researched. The overall gray value and the contrast of the low light image is very low. We choose the fusion strategy based on regional average gradient for the top layer of the long exposure image and short exposure image, which has rich brightness and textural features. The remained layers which represent the edge feature information of the target are based on the fusion strategy based on regional energy. In the process of source image reconstruction with Laplacian pyramid image, we compare the fusion results with four kinds of basal images. The algorithm is tested using Matlab and compared with the different fusion strategies. We use information entropy, average gradient and standard deviation these three objective evaluation parameters for the further analysis of the fusion result. Different low illumination environment experiments show that the algorithm in this paper can rapidly get wide dynamic range while keeping high entropy. Through the verification of this algorithm features, there is a further application prospect of the optimized algorithm. Keywords: high dynamic range imaging, image fusion, multi-exposure image, weight coefficient, information fusion, Laplacian pyramid transform.
Lórenz-Fonfría, Víctor A; Kandori, Hideki
2007-01-01
The number, position, area, and width of the bands in a lifetime distribution give the number of exponentials present in time-resolved data and their time constants, amplitudes, and heterogeneities. The maximum entropy inversion of the Laplace transform (MaxEnt-iLT) provides a lifetime distribution from time-resolved data, which is very helpful in the analysis of the relaxation of complex systems. In some applications both positive and negative values for the lifetime distribution amplitudes are physical, but most studies to date have focused on positive-constrained solutions. In this work, we first discuss optimal conditions to obtain a sign-unrestricted maximum entropy lifetime distribution, i.e., the selection of the entropy function and the regularization value. For the selection of the regularization value we compared four methods: the chi2 criterion and Bayesian inference (already used in sign-restricted MaxEnt-iLT), and the L-curve and the generalized cross-validation methods (not yet used in MaxEnt-iLT to our knowledge). Except for the frequently used chi2 criterion, these methods recommended similar regularization values, providing close to optimum solutions. However, even when an optimal entropy function and regularization value are used, a MaxEnt lifetime distribution will contain noise-induced errors, as well as systematic distortions induced by the entropy maximization (regularization-induced errors). We introduce the concept of the apparent resolution function in MaxEnt, which allows both the noise and regularization-induced errors to be estimated. We show the capability of this newly introduced concept in both synthetic and experimental time-resolved Fourier transform infrared (FT-IR) data from the bacteriorhodopsin photocycle.
NASA Astrophysics Data System (ADS)
Noppel, M.; Vehkamäki, H.; Winkler, P. M.; Kulmala, M.; Wagner, P. E.
2013-10-01
Based on the results of a previous paper [M. Noppel, H. Vehkamäki, P. M. Winkler, M. Kulmala, and P. E. Wagner, J. Chem. Phys. 139, 134107 (2013)], we derive a thermodynamically consistent expression for reversible or minimal work needed to form a dielectric liquid nucleus of a new phase on a charged insoluble conducting sphere within a uniform macroscopic one- or multicomponent mother phase. The currently available model for ion-induced nucleation assumes complete spherical symmetry of the system, implying that the seed ion is immediately surrounded by the condensing liquid from all sides. We take a step further and treat more realistic geometries, where a cap-shaped liquid cluster forms on the surface of the seed particle. We derive the equilibrium conditions for such a cluster. The equalities of chemical potentials of each species between the nucleus and the vapor represent the conditions of chemical equilibrium. The generalized Young equation that relates contact angle with surface tensions, surface excess polarizations, and line tension, also containing the electrical contribution from triple line excess polarization, expresses the condition of thermodynamic equilibrium at three-phase contact line. The generalized Laplace equation gives the condition of mechanical equilibrium at vapor-liquid dividing surface: it relates generalized pressures in neighboring bulk phases at an interface with surface tension, excess surface polarization, and dielectric displacements in neighboring phases with two principal radii of surface curvature and curvatures of equipotential surfaces in neighboring phases at that point. We also re-express the generalized Laplace equation as a partial differential equation, which, along with electrostatic Laplace equations for bulk phases, determines the shape of a nucleus. We derive expressions that are suitable for calculations of the size and composition of a critical nucleus (generalized version of the classical Kelvin-Thomson equation).
NASA Astrophysics Data System (ADS)
Hohenstein, Edward G.; Parrish, Robert M.; Sherrill, C. David; Turney, Justin M.; Schaefer, Henry F.
2011-11-01
Symmetry-adapted perturbation theory (SAPT) provides a means of probing the fundamental nature of intermolecular interactions. Low-orders of SAPT (here, SAPT0) are especially attractive since they provide qualitative (sometimes quantitative) results while remaining tractable for large systems. The application of density fitting and Laplace transformation techniques to SAPT0 can significantly reduce the expense associated with these computations and make even larger systems accessible. We present new factorizations of the SAPT0 equations with density-fitted two-electron integrals and the first application of Laplace transformations of energy denominators to SAPT. The improved scalability of the DF-SAPT0 implementation allows it to be applied to systems with more than 200 atoms and 2800 basis functions. The Laplace-transformed energy denominators are compared to analogous partial Cholesky decompositions of the energy denominator tensor. Application of our new DF-SAPT0 program to the intercalation of DNA by proflavine has allowed us to determine the nature of the proflavine-DNA interaction. Overall, the proflavine-DNA interaction contains important contributions from both electrostatics and dispersion. The energetics of the intercalator interaction are are dominated by the stacking interactions (two-thirds of the total), but contain important contributions from the intercalator-backbone interactions. It is hypothesized that the geometry of the complex will be determined by the interactions of the intercalator with the backbone, because by shifting toward one side of the backbone, the intercalator can form two long hydrogen-bonding type interactions. The long-range interactions between the intercalator and the next-nearest base pairs appear to be negligible, justifying the use of truncated DNA models in computational studies of intercalation interaction energies.
Hohenstein, Edward G; Parrish, Robert M; Sherrill, C David; Turney, Justin M; Schaefer, Henry F
2011-11-07
Symmetry-adapted perturbation theory (SAPT) provides a means of probing the fundamental nature of intermolecular interactions. Low-orders of SAPT (here, SAPT0) are especially attractive since they provide qualitative (sometimes quantitative) results while remaining tractable for large systems. The application of density fitting and Laplace transformation techniques to SAPT0 can significantly reduce the expense associated with these computations and make even larger systems accessible. We present new factorizations of the SAPT0 equations with density-fitted two-electron integrals and the first application of Laplace transformations of energy denominators to SAPT. The improved scalability of the DF-SAPT0 implementation allows it to be applied to systems with more than 200 atoms and 2800 basis functions. The Laplace-transformed energy denominators are compared to analogous partial Cholesky decompositions of the energy denominator tensor. Application of our new DF-SAPT0 program to the intercalation of DNA by proflavine has allowed us to determine the nature of the proflavine-DNA interaction. Overall, the proflavine-DNA interaction contains important contributions from both electrostatics and dispersion. The energetics of the intercalator interaction are are dominated by the stacking interactions (two-thirds of the total), but contain important contributions from the intercalator-backbone interactions. It is hypothesized that the geometry of the complex will be determined by the interactions of the intercalator with the backbone, because by shifting toward one side of the backbone, the intercalator can form two long hydrogen-bonding type interactions. The long-range interactions between the intercalator and the next-nearest base pairs appear to be negligible, justifying the use of truncated DNA models in computational studies of intercalation interaction energies.
Schurkus, Henry F.; Ochsenfeld, Christian
2016-01-21
An atomic-orbital (AO) reformulation of the random-phase approximation (RPA) correlation energy is presented allowing to reduce the steep computational scaling to linear, so that large systems can be studied on simple desktop computers with fully numerically controlled accuracy. Our AO-RPA formulation introduces a contracted double-Laplace transform and employs the overlap-metric resolution-of-the-identity. First timings of our pilot code illustrate the reduced scaling with systems comprising up to 1262 atoms and 10 090 basis functions. .
NASA Astrophysics Data System (ADS)
Khanpour, Hamzeh; Mirjalili, Abolfazl; Tehrani, S. Atashbar
2017-03-01
An analytical solution based on the Laplace transformation technique for the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations is presented at next-to-leading order accuracy in perturbative QCD. This technique is also applied to extract the analytical solution for the proton structure function, F2p(x ,Q2) , in the Laplace s space. We present the results for the separate parton distributions of all parton species, including valence quark densities, the antiquark and strange sea parton distribution functions (PDFs), and the gluon distribution. We successfully compare the obtained parton distribution functions and the proton structure function with the results from GJR08 [Gluck, Jimenez-Delgado, and Reya, Eur. Phys. J. C 53, 355 (2008)], 10.1140/epjc/s10052-007-0462-9 and KKT12 [Khanpour, Khorramian, and Tehrani, J. Phys. G 40, 045002 (2013)], 10.1088/0954-3899/40/4/045002 parametrization models as well as the x -space results using
NASA Astrophysics Data System (ADS)
Dildabek, Gulnar; Orazov, Isabek
2016-08-01
In the present paper, we investigate a nonlocal boundary problem for the Laplace equation in a half-disk, with opposite flows at the part of the boundary. The difference of this problem is the impossibility of direct applying of the Fourier method (separation of variables). Because the corresponding spectral problem for the ordinary differential equation has the system of eigenfunctions not forming a basis. A special system of functions based on these eigenfunctions is constructed. This system has already formed the basis. This new basis is used for solving the nonlocal boundary value problem. The existence and the uniqueness of the classical solution of the problem are proved.
NASA Astrophysics Data System (ADS)
Li, H. J.; Feng, X. S.; Xiang, J.; Zuo, P. B.
2013-06-01
In this paper, the essential technique of Grad-Shafranov (GS) reconstruction is reformulated into an inverse boundary value problems (IBVPs) for Laplace's equation on a circle by introducing a Hilbert transform between the normal and tangent component of the boundary gradients. It is proved that the specified IBVPs have unique solution, given the known Dirichlet and Neumann conditions on certain arc. Even when the arc is reduced to only one point on the circle, it can be inferred logically that the unique solution still exists there on the remaining circle. New solution approach for the specified IBVP is suggested with the help of the introduced Hilbert transform. An iterated Tikhonov regularization scheme is applied to deal with the ill-posed linear operators appearing in the discretization of the new approach. Numerical experiments highlight the efficiency and robustness of the proposed method. According to linearity of the elliptic operator in GS equation, its solution can be divided into two parts. One is solved from a semilinear elliptic equation with an homogeneous Dirichlet boundary condition. The other is solved from the IBVP of Laplace's equation. It is concluded that there exists a unique solution for the so-called elliptic Cauchy problem for the essential technique of GS reconstruction.
Nagy, Péter R; Kállay, Mihály
2017-06-07
An improved algorithm is presented for the evaluation of the (T) correction as a part of our local natural orbital (LNO) coupled-cluster singles and doubles with perturbative triples [LNO-CCSD(T)] scheme [Z. Rolik et al., J. Chem. Phys. 139, 094105 (2013)]. The new algorithm is an order of magnitude faster than our previous one and removes the bottleneck related to the calculation of the (T) contribution. First, a numerical Laplace transformed expression for the (T) fragment energy is introduced, which requires on average 3 to 4 times fewer floating point operations with negligible compromise in accuracy eliminating the redundancy among the evaluated triples amplitudes. Second, an additional speedup factor of 3 is achieved by the optimization of our canonical (T) algorithm, which is also executed in the local case. These developments can also be integrated into canonical as well as alternative fragmentation-based local CCSD(T) approaches with minor modifications. As it is demonstrated by our benchmark calculations, the evaluation of the new Laplace transformed (T) correction can always be performed if the preceding CCSD iterations are feasible, and the new scheme enables the computation of LNO-CCSD(T) correlation energies with at least triple-zeta quality basis sets for realistic three-dimensional molecules with more than 600 atoms and 12 000 basis functions in a matter of days on a single processor.
NASA Astrophysics Data System (ADS)
Tang, H.; Sun, W.
2016-12-01
The theoretical computation of dislocation theory in a given earth model is necessary in the explanation of observations of the co- and post-seismic deformation of earthquakes. For this purpose, computation theories based on layered or pure half space [Okada, 1985; Okubo, 1992; Wang et al., 2006] and on spherically symmetric earth [Piersanti et al., 1995; Pollitz, 1997; Sabadini & Vermeersen, 1997; Wang, 1999] have been proposed. It is indicated that the compressibility, curvature and the continuous variation of the radial structure of Earth should be simultaneously taken into account for modern high precision displacement-based observations like GPS. Therefore, Tanaka et al. [2006; 2007] computed global displacement and gravity variation by combining the reciprocity theorem (RPT) [Okubo, 1993] and numerical inverse Laplace integration (NIL) instead of the normal mode method [Peltier, 1974]. Without using RPT, we follow the straightforward numerical integration of co-seismic deformation given by Sun et al. [1996] to present a straightforward numerical inverse Laplace integration method (SNIL). This method is used to compute the co- and post-seismic displacement of point dislocations buried in a spherically symmetric, self-gravitating viscoelastic and multilayered earth model and is easy to extended to the application of geoid and gravity. Comparing with pre-existing method, this method is relatively more straightforward and time-saving, mainly because we sum associated Legendre polynomials and dislocation love numbers before using Riemann-Merlin formula to implement SNIL.
NASA Astrophysics Data System (ADS)
Nagy, Péter R.; Kállay, Mihály
2017-06-01
An improved algorithm is presented for the evaluation of the (T) correction as a part of our local natural orbital (LNO) coupled-cluster singles and doubles with perturbative triples [LNO-CCSD(T)] scheme [Z. Rolik et al., J. Chem. Phys. 139, 094105 (2013)]. The new algorithm is an order of magnitude faster than our previous one and removes the bottleneck related to the calculation of the (T) contribution. First, a numerical Laplace transformed expression for the (T) fragment energy is introduced, which requires on average 3 to 4 times fewer floating point operations with negligible compromise in accuracy eliminating the redundancy among the evaluated triples amplitudes. Second, an additional speedup factor of 3 is achieved by the optimization of our canonical (T) algorithm, which is also executed in the local case. These developments can also be integrated into canonical as well as alternative fragmentation-based local CCSD(T) approaches with minor modifications. As it is demonstrated by our benchmark calculations, the evaluation of the new Laplace transformed (T) correction can always be performed if the preceding CCSD iterations are feasible, and the new scheme enables the computation of LNO-CCSD(T) correlation energies with at least triple-zeta quality basis sets for realistic three-dimensional molecules with more than 600 atoms and 12 000 basis functions in a matter of days on a single processor.
NASA Astrophysics Data System (ADS)
Kwon, Kibum
A dynamic analysis of the interaction between a crack and an auxetic (negative Poisson ratio)/non-auxetic inclusion is presented. The two most important fracture parameters, namely the stress intensity factors and the T-stress are analyzed by using the symmetric Galerkin boundary element method in the Laplace domain for three different models of crack-inclusion interaction. To investigate the effects of auxetic inclusions on the fracture behavior of composites reinforced by this new type of material, comparisons of the dynamic stress intensity factors and the dynamic T-stress are made between the use of auxetic inclusions as opposed to the use of traditional inclusions. Furthermore, the technique presented in this research can be employed to analyze for the interaction between a crack and a cluster of auxetic/non-auxetic inclusions. Results from the latter models can be employed in crack growth analysis in auxetic-fiber-reinforced composites.
Zhan, X.
2005-01-01
A parallel Fortran-MPI (Message Passing Interface) software for numerical inversion of the Laplace transform based on a Fourier series method is developed to meet the need of solving intensive computational problems involving oscillatory water level's response to hydraulic tests in a groundwater environment. The software is a parallel version of ACM (The Association for Computing Machinery) Transactions on Mathematical Software (TOMS) Algorithm 796. Running 38 test examples indicated that implementation of MPI techniques with distributed memory architecture speedups the processing and improves the efficiency. Applications to oscillatory water levels in a well during aquifer tests are presented to illustrate how this package can be applied to solve complicated environmental problems involved in differential and integral equations. The package is free and is easy to use for people with little or no previous experience in using MPI but who wish to get off to a quick start in parallel computing. ?? 2004 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Goldman, Saul
2009-11-01
The Young-Laplace equation for the pressure of a mechanically stable gas bubble is generalized to include the effects of both surface tension and elastic forces of its surroundings. The latter are taken to be comprised of a soft isotropic material. Generalizations are derived for conditions of constant external pressure and constant system volume. The derived equations are formally exact for a spherical bubble surrounded by a spherical shell of isotropic material, provided that the bubble is sufficiently large for the surface tension to be treated macroscopically, and that the bubble radius is much larger than the thickness of the bubble/soft material interface. The underlying equations are also used to derive a simple expression for the Gibbs free energy of deformation of an elastic medium that surrounds a gas bubble. The possible relevance of this expression to some recently published ideas on decompression sickness ("the bends") is discussed.
NASA Astrophysics Data System (ADS)
Nyamhere, C.; Das, A. G. M.; Auret, F. D.; Chawanda, A.; Mtangi, W.; Odendaal, Q.; Carr, A.
2009-12-01
We have used deep level transient spectroscopy (DLTS), and Laplace-DLTS to investigate the defects created in antimony doped germanium (Ge) by sputtering with 3 keV Ar ions. Hole traps at EV+0.09 eV and EV+0.31 eV and an electron trap at EC-0.38 eV ( E-center) were observed soon after the sputtering process. Room temperature annealing of the irradiated samples over a period of a month revealed a hole trap at EV+0.26 eV. Above room temperature annealing studies revealed new hole traps at EV+0.27 eV, EV+0.30 eV and EV+0.40 eV.
Puszka, Agathe; Hervé, Lionel; Planat-Chrétien, Anne; Koenig, Anne; Derouard, Jacques; Dinten, Jean-Marc
2013-01-01
We show how to apply the Mellin-Laplace transform to process time-resolved reflectance measurements for diffuse optical tomography. We illustrate this method on simulated signals incorporating the main sources of experimental noise and suggest how to fine-tune the method in order to detect the deepest absorbing inclusions and optimize their localization in depth, depending on the dynamic range of the measurement. To finish, we apply this method to measurements acquired with a setup including a femtosecond laser, photomultipliers and a time-correlated single photon counting board. Simulations and experiments are illustrated for a probe featuring the interfiber distance of 1.5 cm and show the potential of time-resolved techniques for imaging absorption contrast in depth with this geometry. PMID:23577292
NASA Astrophysics Data System (ADS)
Khelashvili, A. A.; Nadareishvili, T. P.
2015-01-01
Singular behavior of the Laplace operator in spherical coordinates is investigated. It is shown that in course of transition to the reduced radial wave function in the Schrodinger equation there appears additional term consisting the Dirac delta function, which was unnoted during the full history of physics and mathematics. The possibility of avoiding this contribution from the reduced radial equation is discussed. It is demonstrated that for this aim the necessary and sufficient condition is requirement the fast enough falling of the wave function at the origin. The result does not depend on character of potential—is it regular or singular. The various manifestations and consequences of this observation are considered as well. The corner-stone in our approach is the natural requirement that the solution of the radial equation at the same time must obey to the full equation.
Resolving the EH{sub 6/7} level in 4H-SiC by Laplace-transform deep level transient spectroscopy
Alfieri, G.; Kimoto, T.
2013-04-15
We show that Laplace transform deep level transient spectroscopy (LDLTS) is an effective technique for the separation of the overlapping emission rates of the EH{sub 6} and EH{sub 7} levels, which are known to constitute EH{sub 6/7}, a mid-gap level in n-type 4H-SiC. The analysis of the electron irradiation dose, electric field dependence, and the effects of carbon interstitials injection on the emission rates of EH{sub 6} and EH{sub 7} shows that EH{sub 7} is dominant over EH{sub 6} and confirms that their nature is related to a carbon vacancy.
NASA Astrophysics Data System (ADS)
Gelczuk, Ł.; Kamyczek, P.; Płaczek-Popko, E.; Dąbrowska-Szata, M.
2014-09-01
Electrical properties of commercial silicon carbide (SiC) Schottky rectifiers are investigated through the measurement and analysis of the forward current-voltage (I-V) and reverse capacitance-voltage (C-V) characteristics in a large temperature range. Some of devices show distinct discrepancies in specific ranges of their electrical characteristics, especially the excess current dominates at voltage <1 V and temperature <300 K. Standard deep level transient spectroscopy (DLTS) revealed the presence of a single deep-level defect with activation energy of about 0.3 eV, exhibiting the features characteristic for extended defects (e.g. dislocations), such as logarithmic capture kinetics. Furthermore, high-resolution Laplace DLTS showed that this deep level consists actually of three closely spaced levels with activation energies ranging from about 0.26 eV to 0.29 eV. A strong correlation between these two techniques implies that the revealed trap level is due to extended defects surrounded by point traps or clusters of defects. On the basis of obtained specific features of the deep-level defect, it was proposed that this defect is arguably responsible for the observed Schottky barrier inhomogeneities.
NASA Astrophysics Data System (ADS)
Ebaid, Abdelhalim; Al Sharif, Mohammed A.
2015-06-01
Since the discovery of the carbon nanotubes (CNTs), there is an increasing interest in their applications in industry and medical fields. Attempts of using such CNTs as drug carriers and in cancer therapy in the presence of a magnetic field are now undertaken because of their direct impacts on increasing the thermal conductivity of base fluids. Two types of CNTs are well known for the researchers, the single-walled CNT (SWCNTs) and the multi-walled CNTs (MWCNTs); however, the subject of which one is more effective in treatment of cancer deserves more investigations. The present article discusses the effect of such types of CNTs on the flow and heat transfer of nanofluids in the presence of a magnetic field. Exact analytical solution for the heat equation has been obtained by using the Laplace transform, where the solution is expressed in terms of a new special function, the generalised incomplete gamma function. The effects of various parameters on the fluid velocity, temperature distribution, and heat transfer rates have been introduced. Details of possible applications of the current results in the treatment of cancer have been also discussed.
Soligno, Giuseppe; Dijkstra, Marjolein; van Roij, René
2014-12-28
Many physical problems require explicit knowledge of the equilibrium shape of the interface between two fluid phases. Here, we present a new numerical method which is simply implementable and easily adaptable for a wide range of problems involving capillary deformations of fluid-fluid interfaces. We apply a simulated annealing algorithm to find the interface shape that minimizes the thermodynamic potential of the system. First, for completeness, we provide an analytical proof that minimizing this potential is equivalent to solving the Young-Laplace equation and the Young law. Then, we illustrate our numerical method showing two-dimensional results for fluid-fluid menisci between vertical or inclined walls and curved surfaces, capillary interactions between vertical walls, equilibrium shapes of sessile heavy droplets on a flat horizontal solid surface, and of droplets pending from flat or curved solid surfaces. Finally, we show illustrative three-dimensional results to point out the applicability of the method to micro- or nano-particles adsorbed at a fluid-fluid interface.
Soligno, Giuseppe; Roij, René van; Dijkstra, Marjolein
2014-12-28
Many physical problems require explicit knowledge of the equilibrium shape of the interface between two fluid phases. Here, we present a new numerical method which is simply implementable and easily adaptable for a wide range of problems involving capillary deformations of fluid-fluid interfaces. We apply a simulated annealing algorithm to find the interface shape that minimizes the thermodynamic potential of the system. First, for completeness, we provide an analytical proof that minimizing this potential is equivalent to solving the Young-Laplace equation and the Young law. Then, we illustrate our numerical method showing two-dimensional results for fluid-fluid menisci between vertical or inclined walls and curved surfaces, capillary interactions between vertical walls, equilibrium shapes of sessile heavy droplets on a flat horizontal solid surface, and of droplets pending from flat or curved solid surfaces. Finally, we show illustrative three-dimensional results to point out the applicability of the method to micro- or nano-particles adsorbed at a fluid-fluid interface.
NASA Astrophysics Data System (ADS)
Rodrigues, Davi C.; Mauro, Sebastião; de Almeida, Álefe O. F.
2016-10-01
General relativity extensions based on renormalization group effects are motivated by a known physical principle and constitute a class of extended gravity theories that have some unexplored unique aspects. In this work we develop in detail the Newtonian and post-Newtonian limits of a realization called renormalization group extended general relativity (RGGR). Special attention is given to the external potential effect, which constitutes a type of screening mechanism typical of RGGR. In the Solar System, RGGR depends on a single dimensionless parameter ν¯⊙, and this parameter is such that for ν¯⊙=0 one fully recovers GR in the Solar System. Previously this parameter was constrained to be |ν¯ ⊙|≲10-21 , without considering the external potential effect. Here we show that under a certain approximation RGGR can be cast in a form compatible with the parametrized post-Newtonian (PPN) formalism, and we use both the PPN formalism and the Laplace-Runge-Lenz technique to put new bounds on ν¯⊙, either considering or not the external potential effect. With the external potential effect the new bound reads |ν¯ ⊙|≲10-16 . We discuss the possible consequences of this bound on the dark matter abundance in galaxies.
NASA Astrophysics Data System (ADS)
Li, H.; Feng, X. S.; Xiang, J.; Zuo, P.
2014-12-01
In Li et al. [2013, New approach for solving the inverse boundary value problem of Laplace's equation on a circle: Technique renovation of the Grad-Shafranov (GS) reconstruction, J. Geophys. Res. Space., 118, 2876-2881], a couple of Hilbert transform relations were applied to the study of the ill-posedness for the essential GS reconstructions. In this further study, a detailed derivation for these reciprocal relations are presented in case of the plane circular region, and then the reciprocal relations are extended to apply to the plane rectangular region after a conformal mapping procedure. While for the case of plane rectangular region, it is confronted by a traditional problem of the so-called corner singularities, which divided the extended reciprocal relations into four integrals with end-point singularities. With the help of the extended Euler-Maclaurin expansion, new quadrature schemes are developed for these singular integrals. Benchmark testing with the analytic solutions on a rectangle boundary has also show the efficiency and robustness of these extensions. The new solution approach is also developed with the introduced reciprocal relations, and an iterated Tikhonov regularization scheme is applied to deal with the ill-posed linear operators appearing in the discretization of the new approach. The special case on the rectangular boundary is benchmarked with the analytic solutions. Numerical experiments highlight the efficiency and robustness of the proposed method. A robust solution approach is expected to be developed based on these new results for the GS equation on any 2D region with partial-known boundary conditions.
NASA Astrophysics Data System (ADS)
Hervé, Lionel; Planat-Chrétien, Anne; Di Sieno, Laura; Berger, Michel; Puszka, Agathe; Dalla Mora, Alberto; Contini, Davide; Boso, Gianluca; Dinten, Jean-Marc
2014-03-01
In order to increase sensitivity in the depth of diffusive media and to separate chromophores with distinct spectral signatures, we developed a method to process time-domain/multi-wavelength diffuse optical acquisitions: 3D Reconstructions of chromophore concentrations are performed with an algorithm based on the use of Mellin-Laplace Transform and material basis. A noise weighted data matching term is optimized by using the conjugated gradients method without expressing the Jacobian matrix of the system. As the algorithm uses reference measurements on a known medium, it does not require measurements or computations of the instrument response function of the system. Validations are performed in the reflectance geometry on a tissue-mimicking phantom composed of intralipid and black ink and a cylindrical blue dye inclusion with a radius of 4mm located at 15mm in depth. The optical tomography setup includes a laser whose picosecond pulses are injected via an optical fiber to the probed diffusive medium and the light collected by two fibers (located 15mm apart from the source), is sent to a Single-Photon Avalanche Diode (SPAD) connected to a Time-Correlated Single-Photon Counting (TCSPC) board. The source and two detectors scan the surface of the medium so as to provide 30 source-detector couples, 900 time-bins and 5 wavelength signals. 3D reconstructions performed on the black ink and blue dye materials on a mesh of around 10000 nodes show that we are able to detect, localize and determine the composition of the inclusion and the background.
Cook, Richard D.
2016-05-25
The ParaDIS_lib software is a project that is funded by the DOE ASC Program. Its purpose is to provide visualization and analysis capabilities for the existing ParaDIS parallel dislocation dynamics simulation code.
Pursuing laplace`s vision on modern computers
Schlick, T.
1996-12-31
This contribution is an informal essay based on a talk delivered at the Institute for Mathematics and its Applications (IMA) in Minneapolis, under the summer program in molecular biology, July 18-22, 1994. I exclude many technical details, which can be found elsewhere, and instead focus on the basic ideas of molecular dynamics simulations, with the goal of conveying to students and non-specialists the key concepts of the theory and practice of large-scale simulations. Following a description of the basic idea in molecular dynamics, I discuss some of the practical details involved in simulations of large biological molecules, the numerical timestep problem, and approaches to this problem based on implicit-integration techniques. I end with a perspective of open challenges in the field and directions for future research. 79 refs., 6 figs., 1 tab.
NASA Astrophysics Data System (ADS)
Mtangi, W.; Auret, F. D.; Meyer, W. E.; Legodi, M. J.; Janse van Rensburg, P. J.; Coelho, S. M. M.; Diale, M.; Nel, J. M.
2012-05-01
Effects of annealing ZnO in hydrogen, oxygen, and argon have been investigated using deep level transient spectroscopy (DLTS) and Laplace-DLTS (LDLTS) measurements. Current-voltage (IV) measurements indicate a decrease in zero-bias barrier height for all the annealed samples. Conventional DLTS measurements reveal the presence of three prominent peaks in the un-annealed and annealed samples. A new peak with an activation enthalpy of 0.60 eV has been observed in the H2 annealed samples, while an estimated energy level of 0.67 eV has been observed in Ar annealed samples. O2 annealing does not introduce new peaks but causes a decrease in the concentration of the E3 peak and an increase in concentration of the E1 peak. The concentrations of all the intrinsic defects have decreased after H2 and Ar annealing; with Ar annealing giving peaks with the lowest concentrations. The E2 peak anneals out after annealing ZnO in Ar and H2 at 300 °C. From the annealing behaviour of E3, we have attributed to transition metal ion related defects, while E4 has been explained as a defect, whose formation favours oxygen deficient conditions. Laplace DLTS has successfully been employed to resolve the closely spaced energy levels in the E4 peak, splitting it into three peaks with energy levels, 0.68 eV, 0.58 eV, and 0.50 eV below the minimum of the conduction band for the Ar annealed sample.
NASA Astrophysics Data System (ADS)
Woltjer, L.
1987-06-01
En la reunion celebrada en diciembre dei ano pasado informe al Consejo de mi deseo de terminar mi contrato como Director General de la ESO una vez que fuera aprobado el proyecto dei VLT, que se espera sucedera hacia fines de este aAo. Cuando fue renovada mi designacion hace tres aAos, el Consejo conocia mi intencion de no completar los cinco aAos dei contrato debido a mi deseo de disponer de mas tiempo para otras actividades. Ahora, una vez terminada la fase preparatoria para el VLT, Y habiendose presentado el proyecto formalmente al Consejo el dia 31 de marzo, y esperando su muy probable aprobacion antes dei termino de este ano, me parece que el 10 de enero de 1988 presenta una excelente fecha para que se produzca un cambio en la administracion de la ESO.
NASA Astrophysics Data System (ADS)
Roy, Arpita; Mahadevan, S.; Chakraborty, A.; Pathan, F. M.; Anandarao, B. G.
2010-01-01
The Physical Research Laboratory Advanced Radial-velocity All-sky Search (PARAS) is an efficient fiber-fed cross-dispersed high-resolution echelle spectrograph that will see first light in early 2010. This instrument is being built at the Physical Research laboratory (PRL) and will be attached to the 1.2m telescope at Gurushikhar Observatory at Mt. Abu, India. PARAS has a single-shot wavelength coverage of 370nm to 850nm at a spectral resolution of R 70000 and will be housed in a vacuum chamber (at 1x10-2 mbar pressure) in a highly temperature controlled environment. This renders the spectrograph extremely suitable for exoplanet searches with high velocity precision using the simultaneous Thorium-Argon wavelength calibration method. We are in the process of developing an automated data analysis pipeline for echelle data reduction and precise radial velocity extraction based on the REDUCE package of Piskunov & Valenti (2002), which is especially careful in dealing with CCD defects, extraneous noise, and cosmic ray spikes. Here we discuss the current status of the PARAS project and details and tests of the data analysis procedure, as well as results from ongoing PARAS commissioning activities.
NASA Astrophysics Data System (ADS)
Jia, Pin; Cheng, Linsong; Huang, Shijun; Xu, Zhongyi; Xue, Yongchao; Cao, Renyi; Ding, Guanyang
2017-08-01
This paper provides a comprehensive model for the flow behavior of a two-zone system with discrete fracture network. The discrete fracture network within the inner zone is represented explicitly by fracture segments. The Laplace-transform finite-difference method is used to numerically model discrete fracture network flow, with sufficient flexibility to consider arbitrary fracture geometries and conductivity distributions. Boundary-element method and line-source functions in the Laplace domain are employed to derive a semi-analytical flow solution for the two-zone system. By imposing the continuity of flux and pressure on discrete fracture surfaces, the semi-analytical two-zone system flow model and the numerical fracture flow model are coupled dynamically. The main advantage of the approach occurring in the Laplace domain is that simulation can be done with nodes only for discrete fractures and elements for boundaries and at predetermined, discrete times. Thus, stability and convergence problems caused by time discretization are avoided and the burden of gridding and computation is decreased without loss of important fracture characteristics. The model is validated by comparison with the results from an analytical solution and a fully numerical solution. Flow regime analysis shows that a two-zone system with discrete fracture network may develop six flow regimes: fracture linear flow, bilinear flow, inner zone linear flow, inner zone pseudosteady-state flow, outer zone pseudoradial flow and outer zone boundary-dominated flow. Especially, local solutions for the inner-zone linear flow have the same form with that of a finite conductivity planar fracture and can be correlated with the total length of discrete fractures and an intercept term. In the inner zone pseudosteady-state flow period, the discrete fractures, along with the boundary of the inner zone, will act as virtual closed boundaries, due to the pressure interference caused by fracture network and the
Planar Para Algebras, Reflection Positivity
NASA Astrophysics Data System (ADS)
Jaffe, Arthur; Liu, Zhengwei
2017-05-01
We define a planar para algebra, which arises naturally from combining planar algebras with the idea of ZN para symmetry in physics. A subfactor planar para algebra is a Hilbert space representation of planar tangles with parafermionic defects that are invariant under para isotopy. For each ZN, we construct a family of subfactor planar para algebras that play the role of Temperley-Lieb-Jones planar algebras. The first example in this family is the parafermion planar para algebra (PAPPA). Based on this example, we introduce parafermion Pauli matrices, quaternion relations, and braided relations for parafermion algebras, which one can use in the study of quantum information. An important ingredient in planar para algebra theory is the string Fourier transform (SFT), which we use on the matrix algebra generated by the Pauli matrices. Two different reflections play an important role in the theory of planar para algebras. One is the adjoint operator; the other is the modular conjugation in Tomita-Takesaki theory. We use the latter one to define the double algebra and to introduce reflection positivity. We give a new and geometric proof of reflection positivity by relating the two reflections through the string Fourier transform.
Nodal Solutions for Supercritical Laplace Equations
NASA Astrophysics Data System (ADS)
Dalbono, Francesca; Franca, Matteo
2016-11-01
In this paper we study radial solutions for the following equation Δ u(x)+f (u(x), |x|) = 0, where {x in {Rn}}, n > 2, f is subcritical for r small and u large and supercritical for r large and u small, with respect to the Sobolev critical exponent {2^{*} = 2n/n-2}. The solutions are classified and characterized by their asymptotic behaviour and nodal properties. In an appropriate super-linear setting, we give an asymptotic condition sufficient to guarantee the existence of at least one ground state with fast decay with exactly j zeroes for any j ≥ 0. Under the same assumptions, we also find uncountably many ground states with slow decay, singular ground states with fast decay and singular ground states with slow decay, all of them with exactly j zeroes. Our approach, based on Fowler transformation and invariant manifold theory, enables us to deal with a wide family of potentials allowing spatial inhomogeneity and a quite general dependence on u. In particular, for the Matukuma-type potential, we show a kind of structural stability.
El astronauta de la NASA José Hernández alienta a los estudiantes a que sigan sus sueños. Hernández también habla acerca del papel que juegan los padres para ayudar a que sus hijos hagan realidad s...
Programa de conservacion para aves migratorias neotropicales
Deborah Finch; Marcia Wilson; Roberto Roca
1992-01-01
Mas de 250 especies de aves terrestres migran a Norte America durante la epoca reproductiva para aprovechar los sistemas templados. No obstante, las aves migratorias neotropicales pasan la mayor parte de su ciclo de vida en los habitat tropicales y subtropicales de paises latinoamericanos y caribefios donde viven en una asociacion cercana con las aves residentes. Para...
Functional Expression of Drosophila para Sodium Channels
Warmke, Jeffrey W.; Reenan, Robert A.G.; Wang, Peiyi; Qian, Su; Arena, Joseph P.; Wang, Jixin; Wunderler, Denise; Liu, Ken; Kaczorowski, Gregory J.; Ploeg, Lex H.T. Van der; Ganetzky, Barry; Cohen, Charles J.
1997-01-01
The Drosophila para sodium channel α subunit was expressed in Xenopus oocytes alone and in combination with tipE, a putative Drosophila sodium channel accessory subunit. Coexpression of tipE with para results in elevated levels of sodium currents and accelerated current decay. Para/TipE sodium channels have biophysical and pharmacological properties similar to those of native channels. However, the pharmacology of these channels differs from that of vertebrate sodium channels: (a) toxin II from Anemonia sulcata, which slows inactivation, binds to Para and some mammalian sodium channels with similar affinity (Kd ≅ 10 nM), but this toxin causes a 100-fold greater decrease in the rate of inactivation of Para/TipE than of mammalian channels; (b) Para sodium channels are >10-fold more sensitive to block by tetrodotoxin; and (c) modification by the pyrethroid insecticide permethrin is >100-fold more potent for Para than for rat brain type IIA sodium channels. Our results suggest that the selective toxicity of pyrethroid insecticides is due at least in part to the greater affinity of pyrethroids for insect sodium channels than for mammalian sodium channels. PMID:9236205
Using ParaPost Tenax fiberglass and ParaCore build-up material to restore severely damaged teeth.
Caicedo, Ricardo; Castellon, Paulino
2005-01-01
This article describes a technique using ParaPost Tenax Fiber White, ParaPost Cement, and ParaPost ParaCore build-up material to restore a tooth with a significant loss of tooth structure. After successful root canal therapy, the posts were bonded in the canals and the core was built using ParaPost ParaCore build-up material. At that point, the tooth was prepared to receive a conventional porcelain-fused-to-metal crown.
Calcineurin hydrolysis of para-nitrophenyl phosphorothioate.
Spannaus-Martin, Donna J; Martin, Bruce L
2004-04-01
para-Nitrophenyl phosphorothioate (pNPT) was hydrolyzed by calcineurin at initial rates slightly, but comparable to rates for para-nitrophenyl phosphate (pNPP). Kinetic characterization yielded higher estimates for both Km and Vmax compared to pNPP. Metal ion activation of phosphorothioate hydrolysis was more promiscuous. Unlike the hydrolysis of with pNPP, Ca2+, Mg2+, and Ba2+ activated calcineurin as well as Mn2+.
NASA Astrophysics Data System (ADS)
Dyckmanns, Malte; Vaughan, Owen
2017-06-01
We generalise the hyper-Kähler/quaternionic Kähler (HK/QK) correspondence to include para-geometries, and present a new concise proof that the target manifold of the HK/QK correspondence is quaternionic Kähler. As an application, we construct one-parameter deformations of the temporal and Euclidean supergravity c-map metrics and show that they are para-quaternionic Kähler.
Process for para-ethyltoluene dehydrogenation
Chu, C.C.
1986-06-03
A process is described of dehydrogenating para-ethyltoluene to selectively form para-methylstyrene comprising contacting to para-ethyltoluene under dehydrogenation reaction conditions with a catalyst composition comprising: (a) from about 30% to 60% by weight of iron oxide, calculated as ferric oxide; (b) from about 13% to 48% by weight of a potassium compound, calculated as potassium oxide; and (c) from about 0% to 5% by weight of a chromium compound, calculated as chromic oxide. The improvement is described comprising dehydrogenating the para-ethyltoluene with a catalyst composition comprising, in addition to the components (a), (b) and (c), a modifying component (d) capable of rendering the para-methylstyrene-containing dehydrogenation reaction effluent especially resistant to the subsequent formation of popcorn polymers when the dehydrogenation of para-ethyltoluene is conducted over the modified catalyst, the modifying component (d) being a bismuth compound present to the extent of from about 1% to 20% by weight of the catalyst composition, calculated as bismuth trioxide.
A note on para-holomorphic Riemannian-Einstein manifolds
NASA Astrophysics Data System (ADS)
Ida, Cristian; Ionescu, Alexandru; Manea, Adelina
2016-06-01
The aim of this note is the study of Einstein condition for para-holomorphic Riemannian metrics in the para-complex geometry framework. First, we make some general considerations about para-complex Riemannian manifolds (not necessarily para-holomorphic). Next, using a one-to-one correspondence between para-holomorphic Riemannian metrics and para-Kähler-Norden metrics, we study the Einstein condition for a para-holomorphic Riemannian metric and the associated real para-Kähler-Norden metric on a para-complex manifold. Finally, it is shown that every semi-simple para-complex Lie group inherits a natural para-Kählerian-Norden Einstein metric.
The ParaScope parallel programming environment
NASA Technical Reports Server (NTRS)
Cooper, Keith D.; Hall, Mary W.; Hood, Robert T.; Kennedy, Ken; Mckinley, Kathryn S.; Mellor-Crummey, John M.; Torczon, Linda; Warren, Scott K.
1993-01-01
The ParaScope parallel programming environment, developed to support scientific programming of shared-memory multiprocessors, includes a collection of tools that use global program analysis to help users develop and debug parallel programs. This paper focuses on ParaScope's compilation system, its parallel program editor, and its parallel debugging system. The compilation system extends the traditional single-procedure compiler by providing a mechanism for managing the compilation of complete programs. Thus, ParaScope can support both traditional single-procedure optimization and optimization across procedure boundaries. The ParaScope editor brings both compiler analysis and user expertise to bear on program parallelization. It assists the knowledgeable user by displaying and managing analysis and by providing a variety of interactive program transformations that are effective in exposing parallelism. The debugging system detects and reports timing-dependent errors, called data races, in execution of parallel programs. The system combines static analysis, program instrumentation, and run-time reporting to provide a mechanical system for isolating errors in parallel program executions. Finally, we describe a new project to extend ParaScope to support programming in FORTRAN D, a machine-independent parallel programming language intended for use with both distributed-memory and shared-memory parallel computers.
Ortho-para-hydrogen equilibration on Jupiter
NASA Technical Reports Server (NTRS)
Carlson, Barbara E.; Lacis, Andrew A.; Rossow, William B.
1992-01-01
Voyager IRIS observations reveal that the Jovian para-hydrogen fraction is not in thermodynamic equilibrium near the NH3 cloud top, implying that a vertical gradient exists between the high-temperature equilibrium value of 0.25 at depth and the cloud top values. The height-dependent para-hydrogen profile is obtained using an anisotropic multiple-scattering radiative transfer model. A vertical correlation is found to exist between the location of the para-hydrogen gradient and the NH3 cloud, strongly suggesting that paramagnetic conversion on NH3 cloud particle surfaces is the dominant equilibration mechanism. Below the NH3 cloud layer, the para fraction is constant with depth and equal to the high-temperature equilibrium value of 0.25. The degree of cloud-top equilibration appears to depend on the optical depth of the NH3 cloud layer. Belt-zone variations in the para-hydrogen profile seem to be due to differences in the strength of the vertical mixing.
Kohli, Payal; Desai, Nihar R.; Giugliano, Robert P.; Kim, Jae B.; Somaratne, Ransi; Huang, Fannie; Knusel, Beat; McDonald, Shannon; Abrahamsen, Timothy; Wasserman, Scott M.; Scott, Robert; Sabatine, Marc S.
2013-01-01
Lowering low-density lipoprotein cholesterol (LDL-C) is a cornerstone for the prevention of atherosclerotic heart disease, improving clinical outcomes and reducing vascular mortality in patients with hypercholesterolemia. The clinical benefits of LDL-C reduction appear to extend even to patients starting with LDL-C as low as 60–80 mg/dL prior to initiating therapy. Statins are the first-line agents for treating hypercholesterolemia and are effective in reducing LDL-C, but many patients are unable to achieve their optimal lipid targets despite intensive statin therapy. Therefore, there has been a strong impetus for the development of novel pharmacologic agents designed to lower LDL-C further in patients already on statin therapy. Genetic mutations resulting in altered cholesterol homeostasis provide valuable information regarding novel approaches for treating hypercholesterolemia. To that end, mutations in proprotein convertase subtilisin/kexin type 9 (PCSK9) were linked to altered levels of LDL-C, illustrating this protein’s role in lipid metabolism. PCSK9 promotes degradation of the LDL receptor, preventing its transport back to the cell surface and thereby increasing circulating LDL-C. Conversely, inhibition of PCSK9 can profoundly decrease circulating LDL-C, and thus is an attractive new target for LDL-C–lowering therapy. AMG 145 is a fully human monoclonal immunoglobulin G2 antibody that binds specifically to human PCSK9 and inhibits its interaction with the low-density lipoprotein receptor. In this manuscript, we describe the rationale and design of LDL-C Assessment with PCSK9 Monoclonal Antibody Inhibition Combined With Statin Therapy–Thrombolysis In Myocardial Infarction 57 (LAPLACE-TIMI 57; NCT01380730), a 12-week, randomized, double-blind, dose-ranging, placebo-controlled study designed to assess the safety and efficacy of AMG 145 when added to statin therapy in patients with hypercholesterolemia. PMID:22714699
Laplace Boundary-Value Problem in Paraboloidal Coordinates
ERIC Educational Resources Information Center
Duggen, L.; Willatzen, M.; Voon, L. C. Lew Yan
2012-01-01
This paper illustrates both a problem in mathematical physics, whereby the method of separation of variables, while applicable, leads to three ordinary differential equations that remain fully coupled via two separation constants and a five-term recurrence relation for series solutions, and an exactly solvable problem in electrostatics, as a…
Nonlinear Laplace equation, de Sitter vacua, and information geometry
Loran, Farhang
2005-06-15
Three exact solutions say {phi}{sub 0} of massless scalar theories on Euclidean space, i.e. D=6 {phi}{sup 3}, D=4 {phi}{sup 4} and D=3 {phi}{sup 6} models are obtained which share similar properties. The information geometry of their moduli spaces coincide with the Euclidean AdS{sub 7}, AdS{sub 5} and AdS{sub 4} respectively on which {phi}{sub 0} can be described as a stable tachyon. In D=4 we recognize that the SU(2) instanton density is proportional to {phi}{sub 0}{sup 4}. The original action S[{phi}] written in terms of new scalars {phi}-tilde={phi}-{phi}{sub 0} is shown to be equivalent to an interacting scalar theory on D-dimensional de Sitter background.
Hermann-Bernoulli-Laplace-Hamilton-Runge-Lenz Vector.
ERIC Educational Resources Information Center
Subramanian, P. R.; And Others
1991-01-01
A way for students to refresh and use their knowledge in both mathematics and physics is presented. By the study of the properties of the "Runge-Lenz" vector the subjects of algebra, analytical geometry, calculus, classical mechanics, differential equations, matrices, quantum mechanics, trigonometry, and vector analysis can be reviewed. (KR)
Newton, Laplace, and The Epistemology of Systems Biology
Bittner, Michael L.; Dougherty, Edward R.
2012-01-01
For science, theoretical or applied, to significantly advance, researchers must use the most appropriate mathematical methods. A century and a half elapsed between Newton’s development of the calculus and Laplace’s development of celestial mechanics. One cannot imagine the latter without the former. Today, more than three-quarters of a century has elapsed since the birth of stochastic systems theory. This article provides a perspective on the utilization of systems theory as the proper vehicle for the development of systems biology and its application to complex regulatory diseases such as cancer. PMID:23170064
Solving Laplace equation to investigate the volcanic ground deformation pattern
NASA Astrophysics Data System (ADS)
Brahmi, Mouna; Castaldo, Raffaele; Barone, Andrea; Fedi, Maurizio; Tizzani, Pietro
2017-04-01
Volcanic eruptions are generally preceded by unrest phenomena, which are characterized by variations in the geophysical and geochemical state of the system. The most evident unrest parameters are the spatial and temporal topographic changes, which typically result in uplift or subsidence of the volcano edifice, usually caused by magma accumulation or hot fluid concentration in shallow reservoirs (Denasoquo et al., 2009). If the observed ground deformation phenomenon is very quick and the time evolution of the process shows a linear tendency, we can approximate the problem by using an elastic rheology model of the crust beneath the volcano. In this scenario, by considering the elastic field theory under the Boussinesq (1885) and Love (1892) approximations, we can evaluate the displacement field induced by a generic source in a homogeneous, elastic, half-space at an arbitrary point. To this purpose, we use the depth to extreme points (DEXP) method. By using this approach, we are able to estimate the depth and the geometry of the active source, responsible of the observed ground deformation.
Planck-Scale Mass Equidistribution of Toral Laplace Eigenfunctions
NASA Astrophysics Data System (ADS)
Granville, Andrew; Wigman, Igor
2017-10-01
We study the small scale distribution of the L 2-mass of eigenfunctions of the Laplacian on the two-dimensional flat torus. Given an orthonormal basis of eigenfunctions, Lester and Rudnick (Commun. Math. Phys. 350(1):279-300, 2017) showed the existence of a density one subsequence whose L 2-mass equidistributes more-or-less down to the Planck scale. We give a more precise version of their result showing equidistribution holds down to a small power of log above Planck scale, and also showing that the L 2-mass fails to equidistribute at a slightly smaller power of log above the Planck scale. This article rests on a number of results about the proximity of lattice points on circles, much of it based on foundational work of Javier Cilleruelo.
Hermann-Bernoulli-Laplace-Hamilton-Runge-Lenz Vector.
ERIC Educational Resources Information Center
Subramanian, P. R.; And Others
1991-01-01
A way for students to refresh and use their knowledge in both mathematics and physics is presented. By the study of the properties of the "Runge-Lenz" vector the subjects of algebra, analytical geometry, calculus, classical mechanics, differential equations, matrices, quantum mechanics, trigonometry, and vector analysis can be reviewed. (KR)
On Neumann and Poincare problems for Laplace equation
NASA Astrophysics Data System (ADS)
Ryazanov, Vladimir
2017-09-01
It is proved the existence of nonclassical solutions of the Neumann problem for the harmonic functions in the Jordan rectifiable domains with arbitrary measurable boundary distributions of normal derivatives. The same is stated for a special case of the Poincare problem on directional derivatives. Moreover, it is shown that the spaces of the found solutions have the infinite dimension.
Laplace Boundary-Value Problem in Paraboloidal Coordinates
ERIC Educational Resources Information Center
Duggen, L.; Willatzen, M.; Voon, L. C. Lew Yan
2012-01-01
This paper illustrates both a problem in mathematical physics, whereby the method of separation of variables, while applicable, leads to three ordinary differential equations that remain fully coupled via two separation constants and a five-term recurrence relation for series solutions, and an exactly solvable problem in electrostatics, as a…
Para-methylstyrene from toluene and acetaldehyde
Innes, R.A.; Occelli, M.L.
1984-08-01
High yields of para-methylstyrene (PMS) were obtained in this study by coupling toluene and acetaldehyde then cracking the resultant 1,1-ditolylethane (DTE) to give equimolar amounts of PMS and toluene. In the first step, a total DTE and ''trimer'' yield of 98% on toluene and 93% on acetaldehyde was obtained using 98% sulfuric acid as catalyst at 5-10/sup 0/C. In the second step, a choline chloride-offretite cracked DTE with 84.0% conversion and 91% selectivity to PMS and toluene. Additional PMS can be obtained by cracking the by-product ''trimer'' formed by coupling DTE and toluene with acetaldehyde. Zeolite Rho was as active but yielded less PMS (86%) and produced more para-ethyltoluene (PET), an undesirable by-product.
Para Bombay phenotype--a case report.
Mathai, J; Sulochana, P V; Sathyabhama, S
1997-10-01
Bombay phenotype is peculiar in that red cells are not agglutinated by antisera A, B or H; while serum contains anti A, B and H. Existence of modifying genes at independent loci with variable expression of ABO genes is postulated. We report here a case of partial suppression where antigens could be detected by elution tests and unlike classical Bombay type, normal amount of appropriate blood group substances were present in saliva. This case of para Bombay phenotype was detected as a result of discrepancy in cell and serum group ng. This highlights the importance of both forward and reverse grouping in ABO testing.
On q-DEFORMED Para Oscillators and PARA-q Oscillators
NASA Astrophysics Data System (ADS)
Kumari, M. Krishna; Shanta, P.; Chaturvedi, S.; Srinivasan, V.
Three generalized commutation relations for a single mode of the harmonic oscillator which contains para-bose and q oscillator commutation relations are constructed. These are shown to be inequivalent. The coherent states of the annihilation operator for these three cases are also constructed.
Allergic contact dermatitis to para-phenylenediamine.
Jenkins, David; Chow, Elizabeth T
2015-02-01
Exposure to hair dye is the most frequent route of sensitisation to para-phenylenediamine (PPD), a common contact allergen. International studies have examined the profile of PPD, but Australian-sourced information is lacking. Patients are often dissatisfied with advice to stop dyeing their hair. This study examines patients' characteristics, patch test results and outcomes of PPD allergy from a single Australian centre, through a retrospective analysis of patch test data from 2006 to 2013 at the Liverpool Hospital Dermatology Department. It reviews the science of hair dye allergy, examines alternative hair dyes and investigates strategies for hair dyeing. Of 584 patients, 11 were allergic to PPD. Our PPD allergy prevalence rate of 2% is at the lower end of international reported rates. About half these patients also react to para-toluenediamine (PTD). Affected patients experience a significant lifestyle disturbance. In all, 78% tried alternative hair dyes after the patch test diagnosis and more than half continued to dye their hair. Alternative non-PPD hair dyes are available but the marketplace can be confusing. Although some patients are able to tolerate alternative hair dyes, caution is needed as the risk of developing an allergy to other hair dye ingredients, especially PTD, is high.
Sensitization to para-tertiary-butylphenolformaldehyde resin.
Massone, L; Anonide, A; Borghi, S; Usiglio, D
1996-03-01
Phenolformaldehyde resins, especially the para-tertiary-butylphenolformaldehyde resin (PTBP-FR), are widely used in industry and in numerous materials of everyday use, such as glues, adhesives, or inks. They can cause many occupational and nonoccupational cases of dermatitis. Forty-one patients with positive patch test results to PTBP-FR were selected for this study. They were patch-tested with a series of chemically related compounds and cross-reactions were noted. Phenolformaldehyde resin (PF-R) was frequently positive (65.8%), whereas other compounds gave a much smaller number of positive results. Cases of occupational exposure (24.4%), location of the dermatitis (hands were involved in 46.3% of cases), and possible sources of exposure (shoes were the responsible agent in 12.2% of cases) were evaluated. Phenolformaldehyde resins are an important cause of contact dermatitis and must be studied chemically and clinically to improve the prognosis of sensitized patients.
[Laparoscopic treatment of para-esophageal hernias].
Collet, D; Wagner, T; Sa Cunha, A; Rault, A; Masson, B
2006-10-01
This retrospective study aims at analyzing the functional results obtained in patients operated by laparoscopy for a para-esophageal hernia. From 1994 to 2004, 38 patients underwent a laparoscopic procedure for a symptomatic para-esophageal hiatal hernia of at least 3/4 of the proximal stomach: 27 females and 11 males, mean age 65 years (extreme: 22-84). There was no case on emergency, 4 patients had have at least one episode of intrathoracic volvulus. The operation consisted in gastric reduction into the abdominal cavity, excision of the sac, suture of the crura reinforced with a mesh in 6 patients and the construction of a gastric wrap. A postoperative barium swallow was performed on POD 3 in order to confirm the anatomical result. Mean operating time was 157 minutes (75-480), no case was converted into laparotomy. Four postoperative complications were observed (morbidity 10.8%): one gastric perforation diagnosed on POD 1, 2 severe dysphagias linked to the wrap, and one atelectasia. There was no death in this series. Functional results were evaluated by the mean of a questionnaire in 33 patients who had a follow up more than 6 months. Thirty-three questionnaires have been sent, 3 patients were lost and one was dead. Among the 29 patients analyzed, 14 were very satisfied, 11 were satisfied and 3 were deceived by the operation. Best results are obtained in patients with GERD, dysphagia or postprandial cardiothoracic symptoms. These results compared to the published data allow us to discuss about indications of surgery, the necessity to removal the hernia sac, and the advantages to reinforce the crura by the mean of a non absorbable mesh.
Time domain para hydrogen induced polarization.
Ratajczyk, Tomasz; Gutmann, Torsten; Dillenberger, Sonja; Abdulhussaein, Safaa; Frydel, Jaroslaw; Breitzke, Hergen; Bommerich, Ute; Trantzschel, Thomas; Bernarding, Johannes; Magusin, Pieter C M M; Buntkowsky, Gerd
2012-01-01
Para hydrogen induced polarization (PHIP) is a powerful hyperpolarization technique, which increases the NMR sensitivity by several orders of magnitude. However the hyperpolarized signal is created as an anti-phase signal, which necessitates high magnetic field homogeneity and spectral resolution in the conventional PHIP schemes. This hampers the application of PHIP enhancement in many fields, as for example in food science, materials science or MRI, where low B(0)-fields or low B(0)-homogeneity do decrease spectral resolution, leading to potential extinction if in-phase and anti-phase hyperpolarization signals cannot be resolved. Herein, we demonstrate that the echo sequence (45°-τ-180°-τ) enables the acquisition of low resolution PHIP enhanced liquid state NMR signals of phenylpropiolic acid derivatives and phenylacetylene at a low cost low-resolution 0.54 T spectrometer. As low field TD-spectrometers are commonly used in industry or biomedicine for the relaxometry of oil-water mixtures, food, nano-particles, or other systems, we compare two variants of para-hydrogen induced polarization with data-evaluation in the time domain (TD-PHIP). In both TD-ALTADENA and the TD-PASADENA strong spin echoes could be detected under conditions when usually no anti-phase signals can be measured due to the lack of resolution. The results suggest that the time-domain detection of PHIP-enhanced signals opens up new application areas for low-field PHIP-hyperpolarization, such as non-invasive compound detection or new contrast agents and biomarkers in low-field Magnetic Resonance Imaging (MRI). Finally, solid-state NMR calculations are presented, which show that the solid echo (90y-τ-90x-τ) version of the TD-ALTADENA experiment is able to convert up to 10% of the PHIP signal into visible magnetization.
The para-Bombay phenotype in Chinese persons.
Lin-Chu, M; Broadberry, R E; Tsai, S J; Chiou, P W
1987-01-01
The para-Bombay phenotype occurs more frequently in Oriental than in white populations. This report describes the immunohematologic findings in 20 cases of the para-Bombay phenotype detected over a period of about 15 months in the Chinese population of Taiwan.
Cooling by Para-to-Ortho-Hydrogen Conversion
NASA Technical Reports Server (NTRS)
Sherman, A.; Nast, T.
1983-01-01
Catalyst speeds conversion, increasing capacity of solid hydrogen cooling system. In radial-flow catalytic converter, para-hydrogen is converted to equilibrium mixture of para-hydrogen and ortho-hydrogen as it passes through porous cylinder of catalyst. Addition of catalyst increases capacity of hydrogen sublimation cooling systems for radiation detectors.
Requisitos para utilizar el enlace | Smokefree Español
Espanol.smokefree.gov ofrece apoyo y recursos para norteamericanos que hablan español y quieren dejar de fumar. Este sitio en la red fue creada por la División de Investigación para el Control del Tabaco del Instituto Nacional del Cáncer.
A nontraumatic para-aortic lymphocele complicating nephrolithiasis.
Hyson, E A; Belleza, N A; Lowman, R M
1977-09-01
Many cases of traumatic para-aortic lymphocele have been reported. Recently, a case of nontraumatic para-aortic lymphocele was investigated. The etiologic consideration for this lymphocele formation is either a localized inflammatory process, or fibrosis induced by prior passage of calculi.
Towards a double field theory on para-Hermitian manifolds
NASA Astrophysics Data System (ADS)
Vaisman, Izu
2013-12-01
In a previous paper, we have shown that the geometry of double field theory has a natural interpretation on flat para-Kähler manifolds. In this paper, we show that the same geometric constructions can be made on any para-Hermitian manifold. The field is interpreted as a compatible (pseudo-)Riemannian metric. The tangent bundle of the manifold has a natural, metric-compatible bracket that extends the C-bracket of double field theory. In the para-Kähler case, this bracket is equal to the sum of the Courant brackets of the two Lagrangian foliations of the manifold. Then, we define a canonical connection and an action of the field that correspond to similar objects of double field theory. Another section is devoted to the Marsden-Weinstein reduction in double field theory on para-Hermitian manifolds. Finally, we give examples of fields on some well-known para-Hermitian manifolds.
Towards a double field theory on para-Hermitian manifolds
Vaisman, Izu
2013-12-15
In a previous paper, we have shown that the geometry of double field theory has a natural interpretation on flat para-Kähler manifolds. In this paper, we show that the same geometric constructions can be made on any para-Hermitian manifold. The field is interpreted as a compatible (pseudo-)Riemannian metric. The tangent bundle of the manifold has a natural, metric-compatible bracket that extends the C-bracket of double field theory. In the para-Kähler case, this bracket is equal to the sum of the Courant brackets of the two Lagrangian foliations of the manifold. Then, we define a canonical connection and an action of the field that correspond to similar objects of double field theory. Another section is devoted to the Marsden-Weinstein reduction in double field theory on para-Hermitian manifolds. Finally, we give examples of fields on some well-known para-Hermitian manifolds.
a New Equation of State for Solid para-HYDROGEN
NASA Astrophysics Data System (ADS)
Wang, Lecheng; Le Roy, Robert J.; Roy, Pierre-Nicholas
2015-06-01
Solid para-H_2 is a popular accommodating host for impurity spectroscopy due to its unique softness and the spherical symmetry of para-H_2 in its J}=0 rotational level. To simulate the properties of impurity-doped solid para-H_2, a reliable model for the `soft' pure solid para-H_2 at different pressures is highly desirable. While a couple of experimental and theoretical studies aimed at elucidating the equation of state (EOS) of solid para-H_2 have been reported, the calculated EOS was shown to be heavily dependent on the potential energy surface (PES) between two para-H_2 that was used in the simulations. The current study also demonstrates that different choices of the parameters governing the Quantum Monte Carlo simulation could produce different EOS curves. To obtain a reliable model for pure solid para-H_2, we used a new 1-D para-H_2 PES reported by Faruk et al. that was obtained by averaging over Hinde's highly accurate 6-D H_2--H_2 PES. The EOS of pure solid para-H_2 was calculated using the PIMC algorithm with periodic boundary conditions (PBC). To precisely determine the equilibrium density of solid para-H_2, both the value of the PIMC time step (τ) and the number of particles in the PBC cell were extrapolated to convergence. The resulting EOS agreed well with experimental observations, and the hcp structured solid para-H_2 was found to be more stable than the fcc one at 4.2K, in agreement with experiment. The vibrational frequency shift of para-H_2 as a function of the density of the pure solid was also calculated, and the value of the shift at the equilibrium density is found to agree well with experiment. T. Momose, H. Honshina, M. Fushitani and H. Katsuki, Vib. Spectrosc. 34, 95(2004). M. E. Fajardo, J. Phys. Chem. A 117, 13504 (2013). I. F. Silvera, Rev. Mod. Phys. 52, 393(1980). F. Operetto and F. Pederiva, Phys. Rev. B 73, 184124(2006). T. Omiyinka and M. Boninsegni, Phys. Rev. B 88, 024112(2013). N. Faruk, M. Schmidt, H. Li, R. J. Le Roy, and P
ParaDiS-FEM dislocation dynamics simulation code primer
Tang, M; Hommes, G; Aubry, S; Arsenlis, A
2011-09-27
The ParaDiS code is developed to study bulk systems with periodic boundary conditions. When we try to perform discrete dislocation dynamics simulations for finite systems such as thin films or cylinders, the ParaDiS code must be extended. First, dislocations need to be contained inside the finite simulation box; Second, dislocations inside the finite box experience image stresses due to the free surfaces. We have developed in-house FEM subroutines to couple with the ParaDiS code to deal with free surface related issues in the dislocation dynamics simulations. This primer explains how the coupled code was developed, the main changes from the ParaDiS code, and the functions of the new FEM subroutines.
Cooling by conversion of para to ortho-hydrogen
NASA Technical Reports Server (NTRS)
Sherman, A. (Inventor)
1983-01-01
The cooling capacity of a solid hydrogen cooling system is significantly increased by exposing vapor created during evaporation of a solid hydrogen mass to a catalyst and thereby accelerating the endothermic para-to-ortho transition of the vapor to equilibrium hydrogen. Catalyst such as nickel, copper, iron or metal hydride gels of films in a low pressure drop catalytic reactor are suitable for accelerating the endothermic para-to-ortho conversion.
Ortho- and para-hydrogen in neutron thermalization
Daemen, L. L.; Brun, T. O.
1998-01-01
The large difference in neutron scattering cross-section at low neutron energies between ortho- and para-hydrogen was recognized early on. In view of this difference (more than an order of magnitude), one might legitimately ask whether the ortho/para ratio has a significant effect on the neutron thermalization properties of a cold hydrogen moderator. Several experiments performed in the 60`s and early 70`s with a variety of source and (liquid hydrogen) moderator configurations attempted to investigate this. The results tend to show that the ortho/para ratio does indeed have an effect on the energy spectrum of the neutron beam produced. Unfortunately, the results are not always consistent with each other and much unknown territory remains to be explored. The problem has been approached from a computational standpoint, but these isolated efforts are far from having examined the ortho/para-hydrogen problem in neutron moderation in all its complexity. Because of space limitations, the authors cannot cover, even briefly, all the aspects of the ortho/para question here. This paper will summarize experiments meant to investigate the effect of the ortho/para ratio on the neutron energy spectrum produced by liquid hydrogen moderators.
ParaText : scalable text modeling and analysis.
Dunlavy, Daniel M.; Stanton, Eric T.; Shead, Timothy M.
2010-06-01
Automated processing, modeling, and analysis of unstructured text (news documents, web content, journal articles, etc.) is a key task in many data analysis and decision making applications. As data sizes grow, scalability is essential for deep analysis. In many cases, documents are modeled as term or feature vectors and latent semantic analysis (LSA) is used to model latent, or hidden, relationships between documents and terms appearing in those documents. LSA supplies conceptual organization and analysis of document collections by modeling high-dimension feature vectors in many fewer dimensions. While past work on the scalability of LSA modeling has focused on the SVD, the goal of our work is to investigate the use of distributed memory architectures for the entire text analysis process, from data ingestion to semantic modeling and analysis. ParaText is a set of software components for distributed processing, modeling, and analysis of unstructured text. The ParaText source code is available under a BSD license, as an integral part of the Titan toolkit. ParaText components are chained-together into data-parallel pipelines that are replicated across processes on distributed-memory architectures. Individual components can be replaced or rewired to explore different computational strategies and implement new functionality. ParaText functionality can be embedded in applications on any platform using the native C++ API, Python, or Java. The ParaText MPI Process provides a 'generic' text analysis pipeline in a command-line executable that can be used for many serial and parallel analysis tasks. ParaText can also be deployed as a web service accessible via a RESTful (HTTP) API. In the web service configuration, any client can access the functionality provided by ParaText using commodity protocols ... from standard web browsers to custom clients written in any language.
A Comparative Usage-Based Approach to the Reduction of the Spanish and Portuguese Preposition "Para"
ERIC Educational Resources Information Center
Gradoville, Michael Stephen
2013-01-01
This study examines the frequency effect of two-word collocations involving "para" "to," "for" (e.g. "fui para," "para que") on the reduction of "para" to "pa" (in Spanish) and "pra" (in Portuguese). Collocation frequency effects demonstrate that language speakers…
A Comparative Usage-Based Approach to the Reduction of the Spanish and Portuguese Preposition "Para"
ERIC Educational Resources Information Center
Gradoville, Michael Stephen
2013-01-01
This study examines the frequency effect of two-word collocations involving "para" "to," "for" (e.g. "fui para," "para que") on the reduction of "para" to "pa" (in Spanish) and "pra" (in Portuguese). Collocation frequency effects demonstrate that language speakers…
Hox and ParaHox genes: a review on molluscs.
Biscotti, Maria Assunta; Canapa, Adriana; Forconi, Mariko; Barucca, Marco
2014-12-01
Hox and ParaHox genes are involved in patterning the anterior-posterior body axis in metazoans during embryo development. Body plan evolution and diversification are affected by variations in the number and sequence of Hox and ParaHox genes, as well as by their expression patterns. For this reason Hox and ParaHox gene investigation in the phylum Mollusca is of great interest, as this is one of the most important taxa of protostomes, characterized by a high morphological diversity. The comparison of the works reviewed here indicates that species of molluscs, belonging to different classes, share a similar composition of Hox and ParaHox genes. Therefore evidence suggests that the wide morphological diversity of this taxon could be ascribed to differences in Hox gene interactions and expressions and changes in the Hox downstream genes rather than to Hox cluster composition. Moreover the data available on Hox and ParaHox genes in molluscs compared with those of other Lophotrochozoa shed light on the complex and controversial evolutionary histories that these genes have undergone within protostomes.
Detection of the MW Transition Between Ortho and Para States
NASA Astrophysics Data System (ADS)
Kanamori, Hideto; Dehghani, Zeinab Tafti; Mizoguchi, Asao; Endo, Yasuki
2017-06-01
Thorough the detailed analysis of the hyperfine resolved rotational transitions, we have been pointed out that there exists not a little interaction between ortho and para states in the molecular Hamiltonian of S_2Cl_2. Using the ortho-para mixed molecular wavefunctions derived from the Hamiltonian, we calculated the transition moment and frequency of the ortho-para forbidden transitions in the cm- and mm-wave region, and picked up some promising candidate transitions for the spectroscopic detection. In the experiment, the S_2Cl_2 vapor with Ar buffer gas in a supersonic jet condition was used with FTMW spectrometer at National Chiao Tung University. As a result, seven hyperfine resolved rotational transitions in the cm-wave region were detected as the ortho-para transition at the predicted frequency within the experimental error range. The observed intensity was 10^{-3} smaller than that of an allowed transition, which is also consistent with the prediction. This is the first time the electric dipole transition between ortho and para states has been detected in a free isolated molecule. A. Mizoguchi, S. Ota, H. Kanamori, Y. Sumiyoshi, and Y. Endo, J. Mol. Spectrosc, 250, 86 (2008) Z. T. Dehghani, S. Ota, A. Mizoguchi and H. Kanamori, J. Phys. Chem. A, 117(39), 10041, (2013)
Evolution of invertebrate deuterostomes and Hox/ParaHox genes.
Ikuta, Tetsuro
2011-06-01
Transcription factors encoded by Antennapedia-class homeobox genes play crucial roles in controlling development of animals, and are often found clustered in animal genomes. The Hox and ParaHox gene clusters have been regarded as evolutionary sisters and evolved from a putative common ancestral gene complex, the ProtoHox cluster, prior to the divergence of the Cnidaria and Bilateria (bilaterally symmetrical animals). The Deuterostomia is a monophyletic group of animals that belongs to the Bilateria, and a sister group to the Protostomia. The deuterostomes include the vertebrates (to which we belong), invertebrate chordates, hemichordates, echinoderms and possibly xenoturbellids, as well as acoelomorphs. The studies of Hox and ParaHox genes provide insights into the origin and subsequent evolution of the bilaterian animals. Recently, it becomes apparent that among the Hox and ParaHox genes, there are significant variations in organization on the chromosome, expression pattern, and function. In this review, focusing on invertebrate deuterostomes, I first summarize recent findings about Hox and ParaHox genes. Next, citing unsolved issues, I try to provide clues that might allow us to reconstruct the common ancestor of deuterostomes, as well as understand the roles of Hox and ParaHox genes in the development and evolution of deuterostomes.
β-Cyclodextrin- para-aminosalicylic acid inclusion complexes
NASA Astrophysics Data System (ADS)
Roik, N. V.; Belyakova, L. A.; Oranskaya, E. I.
2010-11-01
Complex formation of β-cyclodextrin with para-aminosalicylic acid in buffer solutions is studied by UV spectroscopy. It is found that the stoichiometric proportion of the components in the β-cyclodextrin-para-aminosalicylic acid inclusion complex is 1:1. The Ketelar equation is used to calculate the stability constants of the inclusion complexes at different temperatures. The thermodynamic parameters of the complex formation process (ΔG, ΔH, ΔS) are calculated using the van't Hoff equation. The 1:1 β-cyclodextrin-para-aminosalicylic acid inclusion complex is prepared in solid form and its characteristics are determined by IR spectroscopic and x-ray diffraction techniques.
Quantum simulation of driven para-Bose oscillators
NASA Astrophysics Data System (ADS)
Alderete, C. Huerta; Rodríguez-Lara, B. M.
2017-01-01
Quantum mechanics allows paraparticles with mixed Bose-Fermi statistics that have not been experimentally confirmed. We propose a trapped-ion scheme whose effective dynamics are equivalent to a driven para-Bose oscillator of even order. Our mapping suggest highly entangled vibrational and internal ion states as the laboratory equivalent of quantum simulated parabosons. Furthermore, we show the generation and reconstruction of coherent oscillations and para-Bose analogs of Gilmore-Perelomov coherent states from population inversion measurements in the laboratory frame. Our proposal, apart from demonstrating an analog quantum simulator of para-Bose oscillators, provides a quantum state engineering tool that foreshadows the potential use of paraparticle dynamics in the design of quantum information systems.
Una técnica para filtrar patrones de fringing
NASA Astrophysics Data System (ADS)
Ostrov, P. G.
Se presenta una nueva técnica para filtrar los patrones de fringing producidos en los CCDs tipo RCA. El método consiste en construir un mapa con los ángulos de inclinación de las franjas en cada punto de la imagen. Este mapa es ulteriormente utilizado para alinear con el patrón de interferencia una ventana estrecha, sobre la que se aplica un filtro de mediana. Este procedimiento permite eliminar la mayor parte del ruido del patrón de fringing sin destruirlo.
Ortho and para-armalcolite samples in Apollo 17.
NASA Technical Reports Server (NTRS)
Haggerty, S. E.
1973-01-01
Two paragenetically contrasting forms of armalcolite are present in basalts from the Apollo 17 Taurus-Littrow landing site. These armalcolites differ in optical properties, in crystal habit and in their distribution between coarse and fine grained rocks. It is proposed to call the two armalcolite forms ortho-armalcolite and para-armalcolite. Texural relationships and the evidence of experimental melting show that ortho-armalcolite is always the first crystalline phase to appear from unusually titanium rich magmas. The origin of para-armalcolite is not yet fully understood.
On some examples of para-Hermite and para-Kähler Einstein spaces with Λ ≠ 0
NASA Astrophysics Data System (ADS)
Chudecki, Adam
2017-02-01
Spaces equipped with two complementary (distinct) congruences of self-dual null strings and at least one congruence of anti-self-dual null strings are considered. It is shown that if such spaces are Einsteinian then the vacuum Einstein field equations can be reduced to a single nonlinear partial differential equation of the second order. Different forms of these equations are analyzed. Finally, several new explicit metrics of the para-Hermite and para-Kähler Einstein spaces with Λ ≠ 0 are presented. Some relation of that metrics to a modern approach to mechanical issues is discussed.
Utilice en forma segura los productos con cebo para roedores
Si se usan de manera inadecuada, los productos con veneno para ratas y ratones podrían hacerle daño a usted, a sus hijos o a sus mascotas. Siempre que use pesticidas lea la etiqueta del producto y siga todas las indicaciones.
Analyzing and Visualizing Cosmological Simulations with ParaView
Woodring, Jonathan; Heitmann, Katrin; Ahrens, James P; Fasel, Patricia; Hsu, Chung-Hsing; Habib, Salman; Pope, Adrian
2011-01-01
The advent of large cosmological sky surveys - ushering in the era of precision cosmology - has been accompanied by ever larger cosmological simulations. The analysis of these simulations, which currently encompass tens of billions of particles and up to a trillion particles in the near future, is often as daunting as carrying out the simulations in the first place. Therefore, the development of very efficient analysis tools combining qualitative and quantitative capabilities is a matter of some urgency. In this paper, we introduce new analysis features implemented within ParaView, a fully parallel, open-source visualization toolkit, to analyze large N-body simulations. A major aspect of ParaView is that it can live and operate on the same machines and utilize the same parallel power as the simulation codes themselves. In addition, data movement is in a serious bottleneck now and will become even more of an issue in the future; an interactive visualization and analysis tool that can handle data in situ is fast becoming essential. The new features in ParaView include particle readers and a very efficient halo finder that identifies friends-of-friends halos and determines common halo properties, including spherical overdensity properties. In combination with many other functionalities already existing within ParaView, such as histogram routines or interfaces to programming languages like Python, this enhanced version enables fast, interactive, and convenient analyses of large cosmological simulations. In addition, development paths are available for future extensions.
The total neutron cross section of liquid para-hydrogen
NASA Astrophysics Data System (ADS)
Celli, M.; Rhodes, N.; Soper, A. K.; Zoppi, M.
1999-12-01
We have measured, using the pulsed neutron source ISIS, the total neutron cross section of liquid para-hydrogen in the vicinity of the triple point. The experimental results compare only qualitatively with the results of the Young and Koppel theory. However, a much better agreement is found once modifications are included in the model which effectively take into account the intermolecular interactions.
"Espanol para ti": A Video Program That Works.
ERIC Educational Resources Information Center
Steele, Elena; Johnson, Holly
2000-01-01
Describes the development of "Espanol para ti," a video program for teaching Spanish at the elementary school level. The program was designed for use in Clark County, Nevada elementary schools and is taught by a certified Spanish teacher via video twice a week, utilizing comprehensible input through visuals, games, and songs that are conducive to…
Sistemas Correctores de Campo Para EL Telescopio Cassegrain IAC80
NASA Astrophysics Data System (ADS)
Galan, M. J.; Cobos, F. J.
1987-05-01
El proyecto de instrumentación de mayor importancia que ha tenido el Instituto de Astrofisica de Canarias en los últimos afios ha sido el diseflo y construcción del te1escopio IAC8O. Este requería del esfuerzo con junto en mec´nica, óptica y electrónica, lo que facilitó la estructuración y el crecimiento de los respectivos grupos de trabajo, que posteriormente se integraron en departamentos En su origen (1977), el telescopio IAC80 fue concebido como un sistema clásico tipo Cassegrain, con una razón focal F/i 1.3 para el sistema Casse grain y una razón focal F/20 para el sistema Coudé. Posteriormente, aunque se mantuvo la filosofia de que el sistema básico fuera el F/11.3, se consideró conveniente el diseño de secundarios para razones focales F/16 y F/32, y se eliminó el de F/20. Sin embargo, dada la importancia relativa que un foco estrictamente fotográfico tiene en un telescopio moderno, diseñado básicamente para fotometría fotoeléctrica y con un campo util mínimamente de 40 minutos de arco, se decídió Ilevar a cabo el diseño de un secundario F/8 con un sistema corrector de campo, pero que estuviera formado únicamente por lentes con superficies esféricas para que asl su construcción fuera posible en España ó en México. La creciente utilización de detectores bidimensionales para fines de investigación astron6mica y la viabilidad de que en un futuro cercano éstos tengan un área sensible cada vez mayor, hicieron atractiva la idea de tener diseñado un sistema corrector de campo para el foco primario (F/3), con un campo útil mínimo de un grado, y también con la limitante de que sus componentes tuvieron sólamente supérficies esféricas. Ambos diseños de los sis-temas correctores de campo se llevaron a cabo, en gran medida, como parte de un proyecto de colaboración e intercambio en el área de diseño y evaluación de sistemas ópticos.
Kit para aplicar la metodología de Lean en el gobierno
Este Kit para comenzar a aplicar la metodología Lean (Gobierno optimizado) ofrece información para ayudar a las agencias de protección ambiental a planificar e implementar iniciativas Lean exitosas.
Para-acetabular periarthritis calcarea: its radiographic manifestations.
Kawashima, A; Murayama, S; Ohuchida, T; Russell, W J
1988-01-01
On retrospective reviews of radiographs, periarthritis calcarea was distinguished from os acetabula by interval radiographic progression and regression. Among 59 men and 51 women, there were 137 instances of para-acetabular calcifications and ossifications, which were morphologically classified as 58 discrete, 58 amorphous, and 21 segmented types. Correlations with other radiographic abnormalities, symptoms, signs, and laboratory abnormalities were sought, but not established. Out of 93 serially imaged opacities, 90 changed, including 37 of the 40 instances (92.5%) of the discrete type and 53 instances (100%) of the amorphous and segmented types--due to periarthritis calcarea. At least 43 of 90 densities were newly developed. Mean age at first detection was 47.7 years. Three of the discrete densities were unchanged and represented os acetabula. Thus, recognition of para-acetabular periarthritis calcarea is not only of academic importance; it can facilitate proper treatment as well.
Focal para-hisian atrial tachycardia with dual exits
Lawrance Jesuraj, M.; Sharada, K.; Sridevi, C.; Narasimhan, C.
2013-01-01
Focal atrial tachycardias (AT) in the right atrium (RA) tend to cluster around the crista terminalis, coronary sinus (CS) region, tricuspid annulus, and para-hisian region. In most cases, the AT focus can be identified by careful activation mapping, and completely eliminated by radiofrequency (RF) catheter ablation. However, RF ablation near the His bundle (HB) carries a risk of inadvertent damage to the atrioventricular (AV) conduction system. Here we describe a patient with an AT originating in the vicinity of the AV node, which was successfully ablated earlier from non-coronary aortic cusp (NCC), and recurred with an exit from para-hisian location. Respiratory excursions of the catheter were associated with migration to the area of HIs. This was successfully ablated during controlled apnoea, using 3D electroanatomic mapping. PMID:23993015
Conversion of para and ortho hydrogen in the Jovian planets
NASA Technical Reports Server (NTRS)
Massie, S. T.; Hunten, D. M.
1982-01-01
A mechanism is proposed which partially equilibrates the para and ortho rotational levels of molecular hydrogen in the atmospheres of Jupiter, Saturn, and Uranus. Catalytic reactions between the free-radical surface sites of aerosol particles and hydrogen modecules yield significant equilibration near 1 bar pressure, if the efficiency of conversion per collision is between 10 to the -8th and 10 to the -10th and the effective eddy mixing coefficient is 10,000 sq cm/sec. At lower pressures the ortho-para ratio retains the value at the top of the cloud layer, except for a very small effect from conversion in the thermosphere. The influence of conversion on the specific heat and adiabatic lapse rate is also investigated. The effect is found to be generally small, though is can rise to 10% inside the aerosol layer.
Production Ratio for Para- and Ortho-Ps in Photodetachment of Ps^-
NASA Astrophysics Data System (ADS)
Igarashi, Akinori
2017-01-01
Para- and ortho-Ps atoms are formed in the photodetachment of positronium negative ion. Since the lifetime against the pair annihilation is much shorter for para-Ps( ns) than for ortho-Ps( ns), the production ratio of para- and ortho-Ps atoms is important for the photodetachment experiments. We have derived the ratio explicitly.
Synthesis of High Molecular Weight Para-Phenylene PBI
1974-11-01
give high molecular weight m-phenylene PBI (Reference 7). The polymer was completely soluble in methanesulfonic acid and 98% formic acid . Polymer with...mono- mer is a white crystalline solid which can be quantitatively hydrolized in an acid medium to give the free TAB. Stoichiometric quantities of IX...WEIGHT "PARA"-PHENYLENE PBI TECHNICAL REPORT AFML-TR-74-199 NOVEMBER 1974 Distribution limited to U.S.Government agencies only, test and evaluation
Photodissociation dynamics of the ortho- and para-xylyl radicals
NASA Astrophysics Data System (ADS)
Pachner, Kai; Steglich, Mathias; Hemberger, Patrick; Fischer, Ingo
2017-08-01
The photodissociation dynamics of the C8H9 isomers ortho- and para-xylyl are investigated in a free jet. The xylyl radicals are generated by flash pyrolysis from 2-(2-methylphenyl)- and 2-(4-methylphenyl) ethyl nitrite and are excited into the D3 state. REMPI- spectra show vibronic structure and the origin of the transition is identified at 32 291 cm-1 for the para- and at 32 132 cm-1 for the ortho-isomer. Photofragment H-atom action spectra show bands at the same energy and thus confirm H-atom loss from xylyl radicals. To gain further insight into the photodissociation dynamics, velocity map images of the hydrogen atom photofragments are recorded. Their angular distribution is isotropic and the translational energy release is in agreement with a dissociation to products in their electronic ground state. Photodissociation of para-xylyl leads to the formation of para-xylylene (C8H8), while the data for ortho-xylyl agree much better with the isomer benzocyclobutene as the dominant molecular fragment rather than ortho-xylylene. In computations we identified a new pathway for the reaction ortho-xylyl → benzocyclobutene + H with a barrier of 3.39 eV (27 340 cm-1), which becomes accessible at the employed excitation energy. It proceeds via a combination of scissoring and rotational motion of the -CH2 and -CH3 groups. However, the observed rate constants measured by delaying the excitation and ionization laser with respect to each other are significantly faster than computed ones, indicating intrinsic non-RRKM behaviour. A comparably high value of around 30% of the excess energy is released as translation of the H-atom photofragment.
Relative Contributions of Agricultural Drift, Para-Occupational ...
Background: Increased pesticide concentrations in house dust in agricultural areas have been attributed to several exposure pathways, including agricultural drift, para-occupational, and residential use. Objective: To guide future exposure assessment efforts, we quantified relative contributions of these pathways using meta-regression models of published data on dust pesticide concentrations. Methods: From studies in North American agricultural areas published from 1995-2015, we abstracted dust pesticide concentrations reported as summary statistics (e.g., geometric means (GM)). We analyzed these data using mixed-effects meta-regression models that weighted each summary statistic by its inverse variance. Dependent variables were either the log-transformed GM (drift) or the log-transformed ratio of GMs from two groups (para-occupational, residential use). Results: For the drift pathway, predicted GMs decreased sharply and nonlinearly, with GMs 64% lower in homes 250 m versus 23 m from fields (inter-quartile range of published data) based on 52 statistics from 7 studies. For the para-occupational pathway, GMs were 2.3 times higher (95% confidence interval [CI]: 1.5-3.3; 15 statistics, 5 studies) in homes of farmers who applied pesticides more versus less recently or frequently. For the residential use pathway, GMs were 1.3 (95%CI: 1.1-1.4) and 1.5 (95%CI: 1.2-1.9) times higher in treated versus untreated homes, when the probability that a pesticide was used for
TELEMEDICINA: UN DESAFÍO PARA AMÉRICA LATINA
Litewka, Sergio
2011-01-01
La telemedicina es una tendencia creciente en la prestación de los servicios médicos. Aunque la eficacia de esta práctica no ha estado bien establecida, es probable que los países en desarrollo compartirán este nuevo paradigma con los desarrollados. Los defensores de la telemedicina en América Latina sostienen que será una herramienta útil para reducir las disparidades y mejorar la accesibilidad de atención de salud. Aunque América Latina quizá se convierta en un lugar para la investigación e investigación de estos procedimientos, no está claro cómo la telemedicina podría contribuir a mejorar la accesibilidad para las poblaciones desfavorecidas, o coexistir con sistemas de atención de salud públicos crónicamente enfermos. Telemedicine is a growing trend in the provision of medical services. Although the effectiveness of this practice has not been well established, it is likely that developing countries will share this new paradigm with developed ones. Supporters of telemedicine in Latin America maintain that it will be a useful tool for reducing disparities and improving health care accessibility. Although Latin America might become a place for research and investigation of these procedures, it is not clear how telemedicine could contribute to improving accessibility for disadvantaged populations, or coexist with chronically ill-funded public healthcare systems. PMID:21625326
TELEMEDICINA: UN DESAFÍO PARA AMÉRICA LATINA.
Litewka, Sergio
2005-01-01
La telemedicina es una tendencia creciente en la prestación de los servicios médicos. Aunque la eficacia de esta práctica no ha estado bien establecida, es probable que los países en desarrollo compartirán este nuevo paradigma con los desarrollados. Los defensores de la telemedicina en América Latina sostienen que será una herramienta útil para reducir las disparidades y mejorar la accesibilidad de atención de salud. Aunque América Latina quizá se convierta en un lugar para la investigación e investigación de estos procedimientos, no está claro cómo la telemedicina podría contribuir a mejorar la accesibilidad para las poblaciones desfavorecidas, o coexistir con sistemas de atención de salud públicos crónicamente enfermos.Telemedicine is a growing trend in the provision of medical services. Although the effectiveness of this practice has not been well established, it is likely that developing countries will share this new paradigm with developed ones. Supporters of telemedicine in Latin America maintain that it will be a useful tool for reducing disparities and improving health care accessibility. Although Latin America might become a place for research and investigation of these procedures, it is not clear how telemedicine could contribute to improving accessibility for disadvantaged populations, or coexist with chronically ill-funded public healthcare systems.
Determination of the Ratio of Ortho Hydrogen and Para Hydrogen
NASA Astrophysics Data System (ADS)
Zhou, D.; Ihas, G. G.; Sullivan, N. S.
2003-03-01
The two different quantum states of hydrogen, ortho-hydrogen and para-hydrogen, possess different properties. The accurate determination of the ortho/para ratio in gaseous, liquid and solid state is important both for research needs and for applications in cryogenic engineering, such as H2 production, transport and storage. NMR can determine the ratio1 accurately, but it is cumbersome and often not practical. Cryogenic applications need a simple and reliable method. We report on the development of a thermal conductivity gauge employing a pure metal thin film that serves as both heater and thermometer for the detection of ortho-para hydrogen ratios in the gaseous state. This ratio-meter has been tested and found to have a nearly pressure-independent voltage response over a broad pressure range with a constant current. The thermal conductivity of hydrogen and nitrogen was measured and found to agree quantitatively with published data. The new development will be presented. *Thanks to Larry Phelps, Bill Malphurs, Stephen Wood, David Hernandez. # Supported by NASA Contract NAG3-2750 Ref. 1. D. Zhou, C. M. Edwards, and N. S. Sullivan, Phys. Rev. Lett. 62, 1528 (1989)
Surgical treatment of para-oesophageal hiatal hernia.
Rogers, M. L.; Duffy, J. P.; Beggs, F. D.; Salama, F. D.; Knowles, K. R.; Morgan, W. E.
2001-01-01
The development of laparoscopic antireflux surgery has stimulated interest in laparoscopic para-oesophageal hiatal hernia repair. This review of our practice over 10 years using a standard transthoracic technique was undertaken to establish the safety and effectiveness of the open technique to allow comparison. Sixty patients with para-oesophageal hiatal hernia were operated on between 1989 and 1999. There were 38 women and 22 men with a median age of 69.5 years. There were 47 elective and 13 emergency presentations. Operation consisted of a left thoracotomy, hernia reduction and crural repair. An antireflux procedure was added in selected patients. There were no deaths among the elective cases and one among the emergency cases. Median follow-up time was 19 months. There was one recurrence (1.5%). Seven patients (12%) required a single oesophagoscopy and dilatation up to 2 years postoperatively but have been asymptomatic since. Two patients (3%) developed symptomatic reflux which has been well controlled on proton-pump inhibitors. Transthoracic para-oesophageal hernia repair can be safely performed with minimal recurrence. PMID:11777134
Para rubber seed oil: new promising unconventional oil for cosmetics.
Lourith, Nattaya; Kanlayavattanakul, Mayuree; Sucontphunt, Apirada; Ondee, Thunnicha
2014-01-01
Para rubber seed was macerated in petroleum ether and n-hexane, individually, for 30 min. The extraction was additionally performed by reflux and soxhlet for 6 h with the same solvent and proportion. Soxhlet extraction by petroleum ether afforded the greatest extractive yield (22.90 ± 0.92%). Although antioxidant activity by means of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay was insignificantly differed in soxhleted (8.90 ± 1.15%) and refluxed (9.02 ± 0.71%) by n-hexane, soxhlet extraction by n-hexane was significantly (p < 0.05) potent scavenged 2,2'-azino-bis(3-ethylbenzothaiazoline)-6-sulfonic acid) or ABTS radical with trolox equivalent antioxidant capacity (TEAC) of 66.54 ± 6.88 mg/100 g oil. This extract was non cytotoxic towards normal human fibroblast cells. In addition, oleic acid and palmitic acid were determined at a greater content than in the seed of para rubber cultivated in Malaysia, although linoleic and stearic acid contents were not differed. This bright yellow extract was further evaluated on other physicochemical characters. The determined specific gravity, refractive index, iodine value, peroxide value and saponification value were in the range of commercialized vegetable oils used as cosmetic raw material. Therefore, Para rubber seed oil is highlighted as the promising ecological ingredient appraisal for cosmetics. Transforming of the seed that is by-product of the important industrial crop of Thailand into cosmetics is encouraged accordingly.
[Genetic analysis of an individual with para-Bombay phenotype].
Lin, Jia-jin; Huang, Ying; Zhu, Sui-yong
2013-04-01
To study genetic characteristics of an individual with para-Bombay phenotype and her family members. ABO and H antigens were detected with routine serological techniques.The entire coding region of FUT1 gene was amplified by polymerase chain reaction (PCR). PCR products was purified with enzymes digestion and directly sequenced. The RBCs of the proband did not agglutinate with H antibody. The proband therefore has a para-Bombay phenotype (Bmh). Direct sequencing indicated the FUT1 sequence of the proband contained a homozygous 547-552 del AG and heterozygous 814A>G mutation, which gave rise to two haplotypes of 547-552delAG, 547-552delAG and 814A>G. The ABO blood type of the proband' s mother and sisters were all B.Sequencing of the FUT1 gene has found heterozygous 547-552 del AG, 814A>G mutations in the mother and elder sister, and heterozygous 547-552 del AG mutation in her younger sister. The FUT1 547-552 del AG and 814 A>G mutations of the proband were inherited from her mother. A complex mutation of the FUT1 gene consisting of 547-55 del AG and 814 A>G has been identified in an individual with para-Bombay phenotype.
The Regulation of para-Nitrophenol Degradation in Pseudomonas putida DLL-E4.
Chen, Qiongzhen; Tu, Hui; Luo, Xue; Zhang, Biying; Huang, Fei; Li, Zhoukun; Wang, Jue; Shen, Wenjing; Wu, Jiale; Cui, Zhongli
2016-01-01
Pseudomonas putida DLL-E4 can efficiently degrade para-nitrophenol and its intermediate metabolite hydroquinone. The regulation of para-nitrophenol degradation was studied, and PNP induced a global change in the transcriptome of P. putida DLL-E4. When grown on PNP, the wild-type strain exhibited significant downregulation of 2912 genes and upregulation of 845 genes, whereas 2927 genes were downregulated and 891 genes upregulated in a pnpR-deleted strain. Genes related to two non-coding RNAs (ins1 and ins2), para-nitrophenol metabolism, the tricarboxylic acid cycle, the outer membrane porin OprB, glucose dehydrogenase Gcd, and carbon catabolite repression were significantly upregulated when cells were grown on para-nitrophenol plus glucose. pnpA, pnpR, pnpC1C2DECX1X2, and pnpR1 are key genes in para-nitrophenol degradation, whereas pnpAb and pnpC1bC2bDbEbCbX1bX2b have lost the ability to degrade para-nitrophenol. Multiple components including transcriptional regulators and other unknown factors regulate para-nitrophenol degradation, and the transcriptional regulation of para-nitrophenol degradation is complex. Glucose utilization was enhanced at early stages of para-nitrophenol supplementation. However, it was inhibited after the total consumption of para-nitrophenol. The addition of glucose led to a significant enhancement in para-nitrophenol degradation and up-regulation in the expression of genes involved in para-nitrophenol degradation and carbon catabolite repression (CCR). It seemed that para-nitrophenol degradation can be regulated by CCR, and relief of CCR might contribute to enhanced para-nitrophenol degradation. In brief, the regulation of para-nitrophenol degradation seems to be controlled by multiple factors and requires further study.
The Regulation of para-Nitrophenol Degradation in Pseudomonas putida DLL-E4
Chen, Qiongzhen; Tu, Hui; Luo, Xue; Zhang, Biying; Huang, Fei; Li, Zhoukun; Wang, Jue; Shen, Wenjing; Wu, Jiale; Cui, Zhongli
2016-01-01
Pseudomonas putida DLL-E4 can efficiently degrade para-nitrophenol and its intermediate metabolite hydroquinone. The regulation of para-nitrophenol degradation was studied, and PNP induced a global change in the transcriptome of P. putida DLL-E4. When grown on PNP, the wild-type strain exhibited significant downregulation of 2912 genes and upregulation of 845 genes, whereas 2927 genes were downregulated and 891 genes upregulated in a pnpR-deleted strain. Genes related to two non-coding RNAs (ins1 and ins2), para-nitrophenol metabolism, the tricarboxylic acid cycle, the outer membrane porin OprB, glucose dehydrogenase Gcd, and carbon catabolite repression were significantly upregulated when cells were grown on para-nitrophenol plus glucose. pnpA, pnpR, pnpC1C2DECX1X2, and pnpR1 are key genes in para-nitrophenol degradation, whereas pnpAb and pnpC1bC2bDbEbCbX1bX2b have lost the ability to degrade para-nitrophenol. Multiple components including transcriptional regulators and other unknown factors regulate para-nitrophenol degradation, and the transcriptional regulation of para-nitrophenol degradation is complex. Glucose utilization was enhanced at early stages of para-nitrophenol supplementation. However, it was inhibited after the total consumption of para-nitrophenol. The addition of glucose led to a significant enhancement in para-nitrophenol degradation and up-regulation in the expression of genes involved in para-nitrophenol degradation and carbon catabolite repression (CCR). It seemed that para-nitrophenol degradation can be regulated by CCR, and relief of CCR might contribute to enhanced para-nitrophenol degradation. In brief, the regulation of para-nitrophenol degradation seems to be controlled by multiple factors and requires further study. PMID:27191401
NASA Astrophysics Data System (ADS)
Uthrakumar, R.; Vesta, C.; Jose, M.; Sugandhi, K.; Krishnan, S.; Jerome Das, S.
2010-08-01
The unidirectional crystal growth technique has been employed for the bulk growth of semi-organic nonlinear optical barium bis-para-nitrophenolate para-nitrophenol tetra hydrate single crystals along the (2 2 0) direction with almost high solute-crystal conversion efficiency. The grown crystal was subjected to single crystal and powder XRD analyses in order to confirm the crystal identity. Optical absorption studies reveal very high transmittance in the entire visible and near IR region. The presence of various functional groups is confirmed by FTIR analysis. Low dielectric loss at high frequency region is indicative of enhanced optical quality with lesser defects. Photoconductivity measurements carried out on the grown crystal reveal the negative photoconducting nature.
ORTHO-PARA SELECTION RULES IN THE GAS-PHASE CHEMISTRY OF INTERSTELLAR AMMONIA
Faure, A.; Hily-Blant, P.; Le Gal, R.; Rist, C.
2013-06-10
The ortho-para chemistry of ammonia in the cold interstellar medium is investigated using a gas-phase chemical network. Branching ratios for the primary reaction chain involved in the formation and destruction of ortho- and para-NH{sub 3} were derived using angular momentum rules based on the conservation of the nuclear spin. We show that the 'anomalous' ortho-to-para ratio of ammonia ({approx}0.7) observed in various interstellar regions is in fact consistent with nuclear spin selection rules in a para-enriched H{sub 2} gas. This ratio is found to be independent of temperature in the range 5-30 K. We also predict an ortho-to-para ratio of {approx}2.3 for NH{sub 2}. We conclude that a low ortho-to-para ratio of H{sub 2} naturally drives the ortho-to-para ratios of nitrogen hydrides below the statistical values.
Amazon Land Wars in the South of Para
NASA Technical Reports Server (NTRS)
Simmons, Cynthia S.; Walker, Robert T.; Arima, Eugenio Y.; Aldrich, Stephen P.; Caldas, Marcellus M.
2007-01-01
The South of Para, located in the heart of the Brazilian Amazon, has become notorious for violent land struggle. Although land conflict has a long history in Brazil, and today impacts many parts of the country, violence is most severe and persistent here. The purpose of this article is to examine why. Specifically, we consider how a particular Amazonian place, the so-called South of Para has come to be known as Brazil's most dangerous badland. We begin by considering the predominant literature, which attributes land conflict to the frontier expansion process with intensified struggle emerging in the face of rising property values and demand for private property associated with capitalist development. From this discussion, we distill a concept of the frontier, based on notions of property rights evolution and locational rents. We then empirically test the persistence of place-based violence in the region, and assess the frontier movement through an analysis of transportation costs. The findings from the analyses indicate that the prevalent theorization of frontier violence in Amazonia does little to explain its persistent and pervasive nature in the South of Para. To fill this gap in understanding, we develop an explanation based the geographic conception of place, and we use contentious politics theory heuristically to elucidate the ways in which general processes interact with place specific history to engender a landscape of violence. In so doing, we focus on environmental, cognitive, and relational mechanisms (and implicated structures), and attempt to deploy them in an explanatory framework that allows direct observation of the accumulating layers of the region's tragic history. We end by placing our discussion within a political ecological context, and consider the implications of the Amazon Land War for the environment.
Amazon Land Wars in the South of Para
NASA Technical Reports Server (NTRS)
Simmons, Cynthia S.; Walker, Robert T.; Arima, Eugenio Y.; Aldrich, Stephen P.; Caldas, Marcellus M.
2007-01-01
The South of Para, located in the heart of the Brazilian Amazon, has become notorious for violent land struggle. Although land conflict has a long history in Brazil, and today impacts many parts of the country, violence is most severe and persistent here. The purpose of this article is to examine why. Specifically, we consider how a particular Amazonian place, the so-called South of Para has come to be known as Brazil's most dangerous badland. We begin by considering the predominant literature, which attributes land conflict to the frontier expansion process with intensified struggle emerging in the face of rising property values and demand for private property associated with capitalist development. From this discussion, we distill a concept of the frontier, based on notions of property rights evolution and locational rents. We then empirically test the persistence of place-based violence in the region, and assess the frontier movement through an analysis of transportation costs. The findings from the analyses indicate that the prevalent theorization of frontier violence in Amazonia does little to explain its persistent and pervasive nature in the South of Para. To fill this gap in understanding, we develop an explanation based the geographic conception of place, and we use contentious politics theory heuristically to elucidate the ways in which general processes interact with place specific history to engender a landscape of violence. In so doing, we focus on environmental, cognitive, and relational mechanisms (and implicated structures), and attempt to deploy them in an explanatory framework that allows direct observation of the accumulating layers of the region's tragic history. We end by placing our discussion within a political ecological context, and consider the implications of the Amazon Land War for the environment.
INTERVENCIÓN EDUCATIVA EFECTIVA EN VIH PARA MUJERES
Miner, Sarah; Poupin, Lauren; Bernales, Margarita; Ferrer, Lilian; Cianelli, Rosina
2016-01-01
RESUMEN En Chile se estima que aproximadamente 38 mil personas viven con el Virus de Inmunodeficiencia Humana [VIH]. En el año 2001, 1.092 mujeres chilenas vivían con VIH, actualmente se cree que hay más de 7.600 mujeres con el virus. Frente a estas cifras surge la necesidad de crear estrategias de prevención dirigidas a mujeres chilenas. Objetivo analizar los estudios ya realizados en la prevención de VIH para determinar qué aspectos se deben incluir en programas exitosos de prevención de VIH en mujeres. Diseño y Método se realizó una revisión de la literatura utilizando la base de datos Proquest, CINAHL, Pubmed y Scielo. Los límites comprendieron: textos completos, de los últimos 10 años, de acceso gratuito y escrito en español o inglés. Se seleccionaron 15 artículos para la revisión. Resultados todos los artículos comprenden la evaluación del efecto de una intervención sobre conocimiento y conductas relacionadas con VIH/SIDA. Catorce muestran resultados significativos en cambios positivos de conducta o conocimientos relacionados con la prevención de VIH. Conclusiones los programas de prevención de VIH en mujeres pueden ser efectivos para lograr cambios de conducta y de conocimiento. Las intervenciones exitosas son aquellas basadas en teorías o modelos de prevención y en cambios de conductas, todas adaptadas a la cultura de la población estudiada. PMID:27667897
RVA: A Plugin for ParaView 3.14
2015-09-04
RVA is a plugin developed for the 64-bit Windows version of the ParaView 3.14 visualization package. RVA is designed to provide support in the visualization and analysis of complex reservoirs being managed using multi-fluid EOR techniques. RVA, for Reservoir Visualization and Analysis, was developed at the University of Illinois at Urbana-Champaign, with contributions from the Illinois State Geological Survey, Department of Computer Science and National Center for Supercomputing Applications. RVA was designed to utilize and enhance the state-of-the-art visualization capabilities within ParaView, readily allowing joint visualization of geologic framework and reservoir fluid simulation model results. Particular emphasis was placed on enabling visualization and analysis of simulation results highlighting multiple fluid phases, multiple properties for each fluid phase (including flow lines), multiple geologic models and multiple time steps. Additional advanced functionality was provided through the development of custom code to implement data mining capabilities. The built-in functionality of ParaView provides the capacity to process and visualize data sets ranging from small models on local desktop systems to extremely large models created and stored on remote supercomputers. The RVA plugin that we developed and the associated User Manual provide improved functionality through new software tools, and instruction in the use of ParaView-RVA, targeted to petroleum engineers and geologists in industry and research. The RVA web site (http://rva.cs.illinois.edu) provides an overview of functions, and the development web site (https://github.com/shaffer1/RVA) provides ready access to the source code, compiled binaries, user manual, and a suite of demonstration data sets. Key functionality has been included to support a range of reservoirs visualization and analysis needs, including: sophisticated connectivity analysis, cross sections through simulation results between
Para-hydrogen narrow filament evaporation at low temperature
NASA Astrophysics Data System (ADS)
Elizarova, T. G.; Gogolin, A. A.; Montero, S.
2012-11-01
Undercooling of liquid para-hydrogen (pH2) below its freezing point at equilibrium (13.8 K) has been shown recently in flowing micro-filaments evaporating in low density background gas [M. Kühnel et al, Phys. Rev. Lett. 106, 245301 (2011)]. An hydrodynamical model accounting for this process is reported here. Analytical expressions for the local temperature T of a filament, averaged over its cross section, are obtained as a function of distance z to the nozzle. Comparison with the experiment is shown. It is shown also that the thermocapillary forces induce a parabolic profile of velocity across the jet.
RVA: A Plugin for ParaView 3.14
2015-09-04
RVA is a plugin developed for the 64-bit Windows version of the ParaView 3.14 visualization package. RVA is designed to provide support in the visualization and analysis of complex reservoirs being managed using multi-fluid EOR techniques. RVA, for Reservoir Visualization and Analysis, was developed at the University of Illinois at Urbana-Champaign, with contributions from the Illinois State Geological Survey, Department of Computer Science and National Center for Supercomputing Applications. RVA was designed to utilize and enhance the state-of-the-art visualization capabilities within ParaView, readily allowing joint visualization of geologic framework and reservoir fluid simulation model results. Particular emphasis was placed on enabling visualization and analysis of simulation results highlighting multiple fluid phases, multiple properties for each fluid phase (including flow lines), multiple geologic models and multiple time steps. Additional advanced functionality was provided through the development of custom code to implement data mining capabilities. The built-in functionality of ParaView provides the capacity to process and visualize data sets ranging from small models on local desktop systems to extremely large models created and stored on remote supercomputers. The RVA plugin that we developed and the associated User Manual provide improved functionality through new software tools, and instruction in the use of ParaView-RVA, targeted to petroleum engineers and geologists in industry and research. The RVA web site (http://rva.cs.illinois.edu) provides an overview of functions, and the development web site (https://github.com/shaffer1/RVA) provides ready access to the source code, compiled binaries, user manual, and a suite of demonstration data sets. Key functionality has been included to support a range of reservoirs visualization and analysis needs, including: sophisticated connectivity analysis, cross sections through simulation results between
Biodegradation of Para Amino Acetanilide by Halomonas sp. TBZ3
Hajizadeh, Nader; Sefidi Heris, Youssof; Zununi Vahed, Sepideh; Vallipour, Javad; Hejazi, Mohammad Amin; Golabi, Sayyed Mahdi; Asadpour-Zeynali, Karim; Hejazi, Mohammad Saeid
2015-01-01
Background: Aromatic compounds are known as a group of highly persistent environmental pollutants. Halomonas sp. TBZ3 was isolated from the highly salty Urmia Lake of Iran. In this study, characterization of a new Halomonas isolate called Halomonas sp. TBZ3 and its employment for biodegradation of para-amino acetanilide (PAA), as an aromatic environmental pollutant, is described. Objectives: This study aimed to characterize the TBZ3 isolate and to elucidate its ability as a biodegradative agent that decomposes PAA. Materials and Methods: Primarily, DNA-DNA hybridization between TBZ3, Halomonas denitrificans DSM18045T and Halomonas saccharevitans LMG 23976T was carried out. Para-amino acetanilide biodegradation was assessed using spectrophotometry and confirmed by gas chromatography-mass spectroscopy (GC-MS). Parameters effective on biodegradation of PAA were optimized by the Response Surface Methodology (RSM). Results: The DNA-DNA hybridization experiments between isolate TBZ3, H. denitrificans and H. saccharevitans revealed relatedness levels of 57% and 65%, respectively. According to GC-MS results, TBZ3 degrades PAA to benzene, hexyl butanoate, 3-methyl-1-heptanol and hexyl hexanoate. Temperature 32.92°C, pH 6.76, and salinity 14% are the optimum conditions for biodegradation with a confidence level of 95% (at level α = 0.05). Conclusions: According to our results, Halomonas sp. TBZ3 could be considered as a biological agent for bioremediation of PAA and possibly other similar aromatic compounds. PMID:26495103
Kilgore, Matthew B; Augustin, Megan M; May, Gregory D; Crow, John A; Kutchan, Toni M
2016-01-01
The Amaryllidaceae alkaloids are a family of amino acid derived alkaloids with many biological activities; examples include haemanthamine, haemanthidine, galanthamine, lycorine, and maritidine. Central to the biosynthesis of the majority of these alkaloids is a C-C phenol-coupling reaction that can have para-para', para-ortho', or ortho-para' regiospecificity. Through comparative transcriptomics of Narcissus sp. aff. pseudonarcissus, Galanthus sp., and Galanthus elwesii we have identified a para-para' C-C phenol coupling cytochrome P450, CYP96T1, capable of forming the products (10bR,4aS)-noroxomaritidine and (10bS,4aR)-noroxomaritidine from 4'-O-methylnorbelladine. CYP96T1 was also shown to catalyzed formation of the para-ortho' phenol coupled product, N-demethylnarwedine, as less than 1% of the total product. CYP96T1 co-expresses with the previously characterized norbelladine 4'-O-methyltransferase. The discovery of CYP96T1 is of special interest because it catalyzes the first major branch in Amaryllidaceae alkaloid biosynthesis. CYP96T1 is also the first phenol-coupling enzyme characterized from a monocot.
Kilgore, Matthew B.; Augustin, Megan M.; May, Gregory D.; Crow, John A.; Kutchan, Toni M.
2016-01-01
The Amaryllidaceae alkaloids are a family of amino acid derived alkaloids with many biological activities; examples include haemanthamine, haemanthidine, galanthamine, lycorine, and maritidine. Central to the biosynthesis of the majority of these alkaloids is a C-C phenol-coupling reaction that can have para-para', para-ortho', or ortho-para' regiospecificity. Through comparative transcriptomics of Narcissus sp. aff. pseudonarcissus, Galanthus sp., and Galanthus elwesii we have identified a para-para' C-C phenol coupling cytochrome P450, CYP96T1, capable of forming the products (10bR,4aS)-noroxomaritidine and (10bS,4aR)-noroxomaritidine from 4′-O-methylnorbelladine. CYP96T1 was also shown to catalyzed formation of the para-ortho' phenol coupled product, N-demethylnarwedine, as less than 1% of the total product. CYP96T1 co-expresses with the previously characterized norbelladine 4′-O-methyltransferase. The discovery of CYP96T1 is of special interest because it catalyzes the first major branch in Amaryllidaceae alkaloid biosynthesis. CYP96T1 is also the first phenol-coupling enzyme characterized from a monocot. PMID:26941773
Oropouche Virus. 3. Entomological Observations from Three Epidemics in Para, Brazil, 1975,
1979-10-06
by block number) OROPOUCHE VIRUS, CULICOIDES PARAENSIS, EPIDEMICS, BRAZIL, PARA I&2 ABSThAC (Cantmus = revers e e* I nessamy and idewtty by block nmbe...8217)URBAN EPIDEMTCS OF OROPOUCHE ORO FEVER IN THREE MUNICIPALITIES IN PARA, BR.tZIL WERE SrUDIED IN 1975. CULICOIDES PARAENSIS GOELDI WERE COLLECTED...Medicine and Hygiene OROPOUCHE VIRUS III. ENTOMOLOGICAL OBSERVATIONS FROM THREE EPIDEMICS IN PARA, BRAZIL, 1975* DONALD R. ROBERTS, ALFRED L. HOCH
NASA Astrophysics Data System (ADS)
Selvakumar, S.; Boobalan, Maria Susai; Anthuvan Babu, S.; Ramalingam, S.; Leo Rajesh, A.
2016-12-01
Single crystals of sodium para-nitrophenolate para-nitrophenol dihydrate (SPPD) were grown by slow evaporation technique and its structure has been studied by FT-IR, FT-Raman and single crystal X-ray diffraction techniques. The optical and electrical properties were characterized by UV-Vis spectrum, and dielectric studies respectively. SPPD was thermally stable up to 128 °C as determined by TG-DTA curves. Using the Kurtz-Perry powder method, the second-harmonic generation efficiency was found to be five times to that of KDP. Third-order nonlinear response was studied using Z-scan technique with a He-Ne laser (632.8 nm) and NLO parameters such as intensity dependent refractive index, nonlinear absorption coefficient and third-order susceptibility were also estimated. The molecular geometry from X-ray experiment in the ground state has been compared using density functional theory (DFT) with appropriate basis set. The first-order hyperpolarizability also calculated using DFT approaches. Stability of the molecule arising from hyperconjugative interactions leading to its nonlinear optical activity and charge delocalization were analyzed using natural bond orbital technique. HOMO-LUMO energy gap value suggests the possibility of charge transfer within the molecule. Based on optimized ground state geometries, Natural bond orbital (NBO) analysis was performed to study donor-acceptor interactions.
Ortho- and para-hydrogen in dense clouds, protoplanets, and planetary atmospheres
NASA Technical Reports Server (NTRS)
Decampli, W. M.; Cameron, A. G. W.; Bodenheimer, P.; Black, D. C.
1978-01-01
If ortho- and para-hydrogen achieve a thermal ratio on dynamical time scales in a molecular hydrogen cloud, then the specific heat is high enough in the temperature range 35-70 K to possibly induce hydrodynamic collapse. The ortho-para ratio in many interstellar cloud fragments is expected to meet this condition. The same may have been true for the primitive solar nebula. Detailed hydrodynamic and hydrostatic calculations are presented that show the effects of the assumed ortho-para ratio on the evolution of Jupiter during its protoplanetary phase. Some possible consequences of a thermalized ortho-para ratio in the atmospheres of the giant planets are also discussed.
Nuevos sistemas de frecuencia intermedia para el IAR
NASA Astrophysics Data System (ADS)
Olalde, J. C.; Perilli, D.; Larrarte, J. J.
Se presenta el diagrama en bloques de los nuevos sistemas de Frecuencia Intermedia para los dos radiómetros instalados en el IAR. Entre las características más importantes del sistema podemos mencionar la posibilidad de conectar cualquiera de las dos antenas a los ``backend" disponibles: analizador espectral de alta resolución (META II) de 0,05 Hz, autocorrelador de 1008 canales y contínuo. Se incorporan al sistema nuevos sintetizadores de frecuencia implementados con PLL y la moderna técnica de síntesis digital directa. Por último, el conjunto del sistema es susceptible de ser configurado por las computadoras de adquisición de datos, supervisadas por otra, que entrega el estado de funcionamiento actual y evita la selección de configuraciones incorrectas por parte del usuario.
Para-phenylenediamine allergy: current perspectives on diagnosis and management
Mukkanna, Krishna Sumanth; Stone, Natalie M; Ingram, John R
2017-01-01
Para-phenylenediamine (PPD) is the commonest and most well-known component of hair dyes. Oxidative hair dyes and dark henna temporary tattoos contain PPD. Individuals may be sensitized to PPD by temporary henna tattooing in addition to dyeing their hair. PPD allergy can cause severe reactions and may result in complications. In recent years, frequency of positive patch test reactions to PPD has been increasing. Cross-sensitization to other contact allergens may occur, in particular to other hair dye components. Hairdressers are at a high risk for PPD allergy and require counseling regarding techniques to minimize exposure and protective measures while handling hair dye. We focus this review on the current perspectives of diagnosis and management of PPD allergy. PMID:28176912
Pneumatic protection applied to an airbag for para-gliders
NASA Astrophysics Data System (ADS)
Raievski, V.; Valladas, G.
1998-02-01
We present a theory of pneumatic protection based on the laws of thermodynamics, elasticity and fluid mechanics. A general pneumatic protection system is made up of several communicating compartments, the differences in pressure of the compartments generating a transfer of mass and energy between them. The transfer offers interesting possibilities to improve the performance of the system. An example of this type of protection in aerial sport is the airbag for para-gliders, it is used in this paper to illustrate the theory. As the pressure in the airbag depends uniquely on its volume, the geometric model in the theory can be simplified. Experiments carried out with crash-test dummies equipped with sensors have confirmed the theoretical predictions.
Substrate mediated smooth growth of para-sexiphenyl on graphene
NASA Astrophysics Data System (ADS)
Poelsema, Bene; Hlawacek, Gregor; Khokhar, Fawad S.; van Gastel, Raoul; Teichert, Christian
2010-03-01
We report on the layer-by-layer growthof lying para-sexiphenyl (6P) molecules on metal supported graphene flakes. The formation of multilayers has been monitored in situ by means of LEEM. μ-LEED has been used to reveal a bulk-like structure of the submonolayer, monolayer and multilayer regime. Graphene is a flexible, highly conductive and transparent electrode material, making it a promising technological substrate for organic semiconductors. 6P is a blue light emitting molecule with a high charge carrier mobility. The combination of an established deposition technique with the unique properties of organic semiconductors and graphene is an enabler for future flexible and cost efficient devices based on small conjugated molecules.
Para-Hydrogen-Enhanced Gas-Phase Magnetic Resonance Imaging
Bouchard, Louis-S.; Kovtunov, Kirill V.; Burt, Scott R.; Anwar,M. Sabieh; Koptyug, Igor V.; Sagdeev, Renad Z.; Pines, Alexander
2007-02-23
Herein, we demonstrate magnetic resonance imaging (MRI) inthe gas phase using para-hydrogen (p-H2)-induced polarization. A reactantmixture of H2 enriched in the paraspin state and propylene gas is flowedthrough a reactor cell containing a heterogenized catalyst, Wilkinson'scatalyst immobilized on modified silica gel. The hydrogenation product,propane gas, is transferred to the NMR magnet and is spin-polarized as aresult of the ALTADENA (adiabatic longitudinal transport and dissociationengenders net alignment) effect. A polarization enhancement factor of 300relative to thermally polarized gas was observed in 1D1H NMR spectra.Enhancement was also evident in the magnetic resonance images. This isthe first demonstration of imaging a hyperpolarized gaseous productformed in a hydrogenation reaction catalyzed by a supported catalyst.This result may lead to several important applications, includingflow-through porous materials, gas-phase reaction kinetics and adsorptionstudies, and MRI in low fields, all using catalyst-free polarizedfluids.
Electron impact ionization dynamics of para-benzoquinone
NASA Astrophysics Data System (ADS)
Jones, D. B.; Ali, E.; Ning, C. G.; Colgan, J.; Ingólfsson, O.; Madison, D. H.; Brunger, M. J.
2016-10-01
Triple differential cross sections (TDCSs) for the electron impact ionization of the unresolved combination of the 4 highest occupied molecular orbitals (4b3g, 5b2u, 1b1g, and 2b3u) of para-benzoquinone are reported. These were obtained in an asymmetric coplanar geometry with the scattered electron being observed at the angles -7.5°, -10.0°, -12.5° and -15.0°. The experimental cross sections are compared to theoretical calculations performed at the molecular 3-body distorted wave level, with a marginal level of agreement between them being found. The character of the ionized orbitals, through calculated momentum profiles, provides some qualitative interpretation for the measured angular distributions of the TDCS.
ParaText : scalable text analysis and visualization.
Dunlavy, Daniel M.; Stanton, Eric T.; Shead, Timothy M.
2010-07-01
Automated analysis of unstructured text documents (e.g., web pages, newswire articles, research publications, business reports) is a key capability for solving important problems in areas including decision making, risk assessment, social network analysis, intelligence analysis, scholarly research and others. However, as data sizes continue to grow in these areas, scalable processing, modeling, and semantic analysis of text collections becomes essential. In this paper, we present the ParaText text analysis engine, a distributed memory software framework for processing, modeling, and analyzing collections of unstructured text documents. Results on several document collections using hundreds of processors are presented to illustrate the exibility, extensibility, and scalability of the the entire process of text modeling from raw data ingestion to application analysis.
Luttinger parameter of quasi-one-dimensional para -H2
NASA Astrophysics Data System (ADS)
Ferré, G.; Gordillo, M. C.; Boronat, J.
2017-02-01
We have studied the ground-state properties of para-hydrogen in one dimension and in quasi-one-dimensional configurations using the path-integral ground-state Monte Carlo method. This method produces zero-temperature exact results for a given interaction and geometry. The quasi-one-dimensional setup has been implemented in two forms: the inner channel inside a carbon nanotube coated with H2 and a harmonic confinement of variable strength. Our main result is the dependence of the Luttinger parameter on the density within the stable regime. Going from one dimension to quasi-one dimension, keeping the linear density constant, produces a systematic increase of the Luttinger parameter. This increase is, however, not enough to reach the superfluid regime and the system always remain in the quasicrystal regime, according to Luttinger liquid theory.
Sponges, Tubules and Modulated Phases of Para-Antinematic Membranes
NASA Astrophysics Data System (ADS)
Fournier, J. B.; Galatola, P.
1997-10-01
We theoretically analyze the behavior of membranes presenting a nematic susceptibility, induced by the presence of anisotropic phospholipids having a quadrupolar nematic symmetry. This kind of anisotropic phospholipids is either naturally found in some biological membranes, or can be chemically tailored by linking pairs of single surfactants at the level of their polar heads, giving rise to so-called “gemini” surfactants. We predict that such membranes can acquire a non-zero paranematic order induced by the membrane curvature, which in turn produces curvature instabilities. We call the resulting paranematic order para-antinematic, since it is opposite on opposite sides of the membrane. We find phase transitions toward sponges (L3), tubules, or modulated “egg-carton” phases.
Ortho-Para Mixing Hyperfine Interaction in the H2O+ Ion and Nuclear Spin Equilibration
NASA Astrophysics Data System (ADS)
Tanaka, Keiichi; Harada, Kensuke; Oka, Takeshi
2013-10-01
The ortho to para conversion of water ion, H2O+, due to the interaction between the magnetic moments of the unpaired electron and protons has been theoretically studied to calculate the spontaneous emission lifetime between the ortho- and para-levels. The electron spin-nuclear spin interaction term, Tab(Sa-Ib + Sb-Ia) mixes ortho (I = 1) and para (I = 0) levels to cause the -forbidden- ortho to para |-I| = 1 transition. The mixing term with Tab = 72.0 MHz is 4 orders of magnitude higher for H2O+ than for its neutral counterpart H2O where the magnetic field interacting with proton spins is by molecular rotation rather than the free electron. The resultant 108 increase of ortho to para conversion rate possibly makes the effect of conversion in H2O+ measurable in laboratories and possibly explains the anomalous ortho to para ratio recently reported by Herschel heterodyne instrument for the far-infrared (HIFI) observation. Results of our calculations show that the ortho - para mixings involving near-degenerate ortho and para levels are high (-10-3), but they tend to occur at high energy levels, -300 K. Because of the rapid spontaneous emission, such high levels are not populated in diffuse clouds unless the radiative temperature of the environment is very high. The low-lying 101 (para) and 111 (ortho) levels of H2O+ are mixed by -10-4 making the spontaneous emission lifetime for the para 101 - ortho 000 transition 520 years and 5200 years depending on the F value of the hyperfine structure. Thus the ortho - para conversion due to the unpaired electron is not likely to seriously affect thermalization of interstellar H2O+ unless either the radiative temperature is very high or number density of the cloud is very low.
The Ratio of Ortho- to Para-H2 in Photodissociation Regions
NASA Technical Reports Server (NTRS)
Sternberg, Amiel; Neufeld, David A.
1999-01-01
We discuss the ratio of ortho- to para-H2 in photodissociation regions (PDRs). We draw attention to an apparent confusion in the literature between the ortho-to-para ratio of molecules in FUV-pumped vibrationally excited states and the total H2 ortho-to-para abundance ratio. These ratios are not the same because the process of FUV pumping of fluorescent H2 emission in PDRs occurs via optically thick absorption lines. Thus gas with an equilibrium ratio of ortho- to para-H2 equal to 3 will yield FUV-pumped vibrationally excited ortho-to-para ratios smaller than 3, because the ortho-H2 pumping rates are preferentially reduced by optical depth effects. Indeed, if the ortho and para pumping lines are on the "square root" part of the curve of growth, then the expected ratio of ortho and para vibrational line strengths is 3(sup 1/2) approximately 1.7, close to the typically observed value. Thus, contrary to what has sometimes been stated in the literature, most previous measurements of the ratio of ortho- to para-H2 in vibrationally excited states are entirely consistent with a total ortho-to-para ratio of 3, the equilibrium value for temperatures greater than 200 K. We present an analysis and several detailed models that illustrate the relationship between the total ratios of ortho- to para-H2 and the vibrationally excited ortho-to-para ratios in PDRs. Recent Infrared Space Observatory measurements of pure rotational and vibrational H2 emissions from the PDR in the star-forming region S140 provide strong observational support for our conclusions.
The Ratio of Ortho- to Para-H2 in Photodissociation Regions
NASA Technical Reports Server (NTRS)
Sternberg, Amiel; Neufeld, David A.
1999-01-01
We discuss the ratio of ortho- to para-H2 in photodissociation regions (PDRs). We draw attention to an apparent confusion in the literature between the ortho-to-para ratio of molecules in FUV-pumped vibrationally excited states and the total H2 ortho-to-para abundance ratio. These ratios are not the same because the process of FUV pumping of fluorescent H2 emission in PDRs occurs via optically thick absorption lines. Thus gas with an equilibrium ratio of ortho- to para-H2 equal to 3 will yield FUV-pumped vibrationally excited ortho-to-para ratios smaller than 3, because the ortho-H2 pumping rates are preferentially reduced by optical depth effects. Indeed, if the ortho and para pumping lines are on the "square root" part of the curve of growth, then the expected ratio of ortho and para vibrational line strengths is 3(sup 1/2) approximately 1.7, close to the typically observed value. Thus, contrary to what has sometimes been stated in the literature, most previous measurements of the ratio of ortho- to para-H2 in vibrationally excited states are entirely consistent with a total ortho-to-para ratio of 3, the equilibrium value for temperatures greater than 200 K. We present an analysis and several detailed models that illustrate the relationship between the total ratios of ortho- to para-H2 and the vibrationally excited ortho-to-para ratios in PDRs. Recent Infrared Space Observatory measurements of pure rotational and vibrational H2 emissions from the PDR in the star-forming region S140 provide strong observational support for our conclusions.
Ortho-para mixing hyperfine interaction in the H2O+ ion and nuclear spin equilibration.
Tanaka, Keiichi; Harada, Kensuke; Oka, Takeshi
2013-10-03
The ortho to para conversion of water ion, H2O(+), due to the interaction between the magnetic moments of the unpaired electron and protons has been theoretically studied to calculate the spontaneous emission lifetime between the ortho- and para-levels. The electron spin-nuclear spin interaction term, Tab(SaΔIb + SbΔIa) mixes ortho (I = 1) and para (I = 0) levels to cause the "forbidden" ortho to para |ΔI| = 1 transition. The mixing term with Tab = 72.0 MHz is 4 orders of magnitude higher for H2O(+) than for its neutral counterpart H2O where the magnetic field interacting with proton spins is by molecular rotation rather than the free electron. The resultant 10(8) increase of ortho to para conversion rate possibly makes the effect of conversion in H2O(+) measurable in laboratories and possibly explains the anomalous ortho to para ratio recently reported by Herschel heterodyne instrument for the far-infrared (HIFI) observation. Results of our calculations show that the ortho ↔ para mixings involving near-degenerate ortho and para levels are high (∼10(-3)), but they tend to occur at high energy levels, ∼300 K. Because of the rapid spontaneous emission, such high levels are not populated in diffuse clouds unless the radiative temperature of the environment is very high. The low-lying 101 (para) and 111 (ortho) levels of H2O(+) are mixed by ∼10(-4) making the spontaneous emission lifetime for the para 101 → ortho 000 transition 520 years and 5200 years depending on the F value of the hyperfine structure. Thus the ortho ↔ para conversion due to the unpaired electron is not likely to seriously affect thermalization of interstellar H2O(+) unless either the radiative temperature is very high or number density of the cloud is very low.
USDA-ARS?s Scientific Manuscript database
En este articulo se reporta por primera vez para el Peru una especies del genero Nielsonia Young, 1977, de material procedente del Departamento de Tumbes. El genero ha sido reportada anteriormente de Ecuador, como unico registro para Sudamerica, y America Central. El unico especimen hembra encontra...
Guía para la evaluación del riesgo de los polinizadores
La Guía para la evaluación del riesgo de los polinizadores de la EPA es parte de una estrategia de la evaluación de los riesgos que presentan los pesticidas para las abejas a fin de mejorar la protección de los polinizadores.
Rate of para-aortic lymph node micrometastasis in patients with locally advanced cervical cancer
Zand, Behrouz; Euscher, Elizabeth D.; Soliman, Pamela T.; Schmeler, Kathleen M.; Coleman, Robert L.; Frumovitz, Michael; Jhingran, Anuja; Ramondetta, Lois M.; Ramirez, Pedro T.
2014-01-01
Objective Patients with micrometastasis to para-aortic lymph nodes may benefit from extended field chemoradiation. To determine the rate of para-aortic node micrometastasis in patients with locally advanced cervical cancer undergoing laparoscopic extraperitoneal para-aortic lymphadenectomy Methods We prospectively identified consecutive patients diagnosed with stage IB2-IVA biopsy-proven cervical cancer. Eligible patients included those who were candidates for treatment with radiotherapy and concurrent chemotherapy and had no evidence of para-aortic lymphadenopathy (all lymph nodes < 2 cm in diameter) by preoperative computed tomography or magnetic resonance imaging. All patients underwent preoperative positron emission tomography/computed tomography and laparoscopic extraperitoneal para-aortic lymphadenectomy. All lymph nodes were assessed for metastasis by routine hematoxylin-eosin (H&E) staining. Ultrastaging (serial sectioning) and immunohistochemical analysis were performed in H&E-negative specimens. Results Thirteen (22%) of 60 consecutive patients had para-aortic lymph node metastases detected on routine H&E staining. Of the remaining 47 patients, one (2.1%) had evidence of micrometastasis, which was detected by ultrastaging. This patient completed whole pelvic radiotherapy and chemotherapy but had a recurrence 27 months after completion of therapy. Conclusions The rate of para-aortic node micrometastasis in patients with locally advanced cervical cancer is low. The role of routine ultrastaging and immunohistochemical analysis in such patients remains uncertain. Future studies are needed to determine the clinical impact of para-aortic node micrometastasis in patients with locally advanced cervical cancer. PMID:20837355
The parA resolvase performs site-specific genomic excision in Arabidopsis
USDA-ARS?s Scientific Manuscript database
We have designed a site-specific excision detection system in Arabidopsis to study the in planta activity of the small serine recombinase ParA. Using a transient expression assay as well as stable transgenic plant lines, we show that the ParA recombinase is catalytically active and capable of perfo...
Norma para la Certificación de Aplicadores de Plaguicidas Revisada
La EPA emitió una propuesta para la revisión de la norma para la Certificación de Aplicadores de Plaguicidas. La norma ayudará a mantener nuestras comunidades seguras, salvaguardar el medio ambiente y reducir el riesgo a los que aplican los plaguicidas.
Overproduction and localization of Mycobacterium tuberculosis ParA and ParB proteins
Maloney, Erin; Madiraju, Murty; Rajagopalan, Malini
2011-01-01
SUMMARY The ParA and ParB family proteins are required for accurate partitioning of replicated chromosomes. The Mycobacterium tuberculosis genome contains parB, parA and two parA homologs, Rv1708 and Rv3213c. It is unknown if parA and its homologs are functionally related. To understand the roles of ParA and ParB proteins in M. tuberculosis cell cycle, we have evaluated the consequences of their overproduction and visualized their localization patterns in M. smegmatis. We show that cells overproducing of ParA, Rv1708 and Rv3213c and ParB are filamentous and multinucleoidal indicating defects in cell cycle progression. Visualization of green-fluorescent protein fusions of ParA and its homologues showed similar localization patterns with foci at poles, quarter-cell, midcell positions and spiral-like structures indicating that they are functionally related. On the other hand, the ParBGFP fusion protein localized only to the cell poles. The cyan and yellow fluorescent fusion proteins of ParA and ParB, respectively, colocalized at the cell poles indicating that these proteins interact and possibly associate with the chromosomal origin of replication. Collectively our results suggest that the M. tuberculosis Par proteins play important roles in cell cycle progression. PMID:20006309
Taylor-Laplace Expansions of the Yukawa and Related Potential Energy Functions.
1981-08-01
thle ’Yukawa po tenilt iaI i tseIf. Inl thle I iiit a,, thle 20 continued e xponei’i t 3 van is hes , t he Yu kawa pot en t i a I trains f’ rms i l the...analyses of nuclear models . The Woods-Saxon potential has a simple form: _-VO 1 l ’Ws 1+ exp[(r-rO)/p]. This function does not easily admit a Fourier
NASA Astrophysics Data System (ADS)
Turmetov, B. Kh.
2016-12-01
In the paper in a class of regular harmonic functions we study properties of some integro-differential operators that generalize the operators of fractional differentiation in Hadamard sense. These operators transfer regular harmonic functions to the same function, and are inverse to the regular harmonic functions. Boundary value problem with the boundary operator of fractional order is studied in the exterior of the unit sphere. The considered problem generalizes the well-known Neumann problem on boundary operators of fractional order. We prove a theorem on existence and uniqueness of solutions of the problem. Moreover, an integral representation of the problem solution is obtained.
LaPlace Transform1 Adaptive Control Law in Support of Large Flight Envelope Modeling Work
NASA Technical Reports Server (NTRS)
Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira
2011-01-01
This paper presents results of a flight test of the L1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented are in support of nonlinear aerodynamic modeling and instrumentation calibration.
Operation Plumbbob. Program 2. Neutron and Gamma Radiation from Shot Laplace
1984-10-31
plutonium, neptunium , uranium, and sulfur for ground-surface measurements, and gold, cadmium-shielded gold, and sulfur for soil-depth measurements...gold, cadmium-shielded gold, plutoniurn. neptunium , uranium, and sulfur. Thermal- neutron flux was measured by means of the gold and cadmium-gold...exception of plutonium, have various threshold energies in the fast- neutron region. These effective thresholds are: neptunium , 0.63 Mev; uranium
XYZ-like spectra from Laplace sum rule at N2LO in the chiral limit
NASA Astrophysics Data System (ADS)
Albuquerque, R.; Narison, S.; Fanomezana, F.; Rabemananjara, A.; Rabetiarivony, D.; Randriamanatrika, G.
2016-12-01
We present new compact integrated expressions of QCD spectral functions of heavy-light molecules and four-quark XY Z-like states at lowest order (LO) of perturbative (PT) QCD and up to d = 8 condensates of the Operator Product Expansion (OPE). Then, by including up to next-to-next leading order (N2LO) PT QCD corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results from QCD spectral sum rules (QSSR), on the XY Z-like masses and decay constants which suffer from the ill-defined heavy quark mass. PT N3LO corrections are estimated using a geometric growth of the PT series and are included in the systematic errors. Our optimal results based on stability criteria are summarized in Tables 11-14 and compared, in Sec. 10, with experimental candidates and some LO QSSR results. We conclude that the masses of the XZ observed states are compatible with (almost) pure JPC = 1+±, 0++ molecule or/and four-quark states. The ones of the 1-±, 0-± molecule/four-quark states are about 1.5 GeV above the Yc,b mesons experimental candidates and hadronic thresholds. We also find that the couplings of these exotics to the associated interpolating currents are weaker than that of ordinary D,B mesons (fDD ≈ 10-3f D) and may behave numerically as 1/m¯b3/2 (respectively 1/m¯b) for the 1+, 0+ (respectively 1-, 0-) states which can stimulate further theoretical studies of these decay constants.
The Masked Sample Covariance Estimator: An Analysis via the Matrix Laplace Transform
2012-02-01
to focus on estimating only the signi cant entries. To analyze this approach, Levina and Vershynin (2011) introduce a formalism called masked...contrast to the sample complexity n = O(B log5 p) obtained by Levina and Vershynin. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...covariance matrix is nearly sparse and to focus on estimating only the significant entries. To analyze this approach, Levina and Vershynin (2011) introduce
Laplace operators of infinite-dimensional Lie algebras and theta functions
Kac, Victor G.
1984-01-01
Until recently, the generalized Casimir operator constructed by Kac [Kac, V. G. (1974) Funct. Anal. Appl. 8, 68-70] has been the only known element of the center of a completion of the enveloping algebra of a Kac-Moody algebra. It has been conjectured [Deodhar, V. V., Gabber, O. & Kac, V. G. (1982) Adv. Math. 45, 92-116], however, that the image of the Harish-Chandra homomorphism contains all theta functions defined on the interior of the complexified Tits cone and hence separates the orbits of the Weyl group. Developing the ideas of Feigin and Fuchs [Feigin, B. L. & Fuchs, D. B. (1983) Dokl. Akad. Nauk SSSR 269, 1057-1060], I prove this conjecture. Another application of this method is the Chevalley type restriction theorem for simple finite-dimensional Lie superalgebras. PMID:16593411
Active exterior cloaking for the 2D Laplace and Helmholtz equations.
Vasquez, Fernando Guevara; Milton, Graeme W; Onofrei, Daniel
2009-08-14
A new cloaking method is presented for 2D quasistatics and the 2D Helmholtz equation that we speculate extends to other linear wave equations. For 2D quasistatics it is proven how a single active exterior cloaking device can be used to shield an object from surrounding fields, yet produce very small scattered fields. The problem is reduced to finding a polynomial which is close to 1 in a disk and close to 0 in another disk, and such a polynomial is constructed. For the 2D Helmholtz equation it is numerically shown that three exterior cloaking devices placed around the object suffice to hide it.
Application of DLTS and Laplace-DLTS to defect characterization in high-resistivity semiconductors
NASA Astrophysics Data System (ADS)
Makarenko, L. F.; Evans-Freeman, J. H.
2007-12-01
This paper shows that the use of conventional analytical procedures to determine defect parameters from DLTS spectra may lead to erroneous results for high-resistivity semiconductors. The effect is observed when the temperature range of a DLTS peak encompasses the temperature at which the equilibrium Fermi level intersects the energy level of defect under study. Based on this Fermi level effect, a procedure is proposed to determine the occupancy levels for defects with a strong temperature dependence of the carrier capture cross-section. It has been found that the procedure can be useful for characterization of positive-U states through to negative-U centers in semiconductors.
On the Analytical and Numerical Properties of the Truncated Laplace Transform I
2014-09-05
PERSON a. REPORT unclassified b. ABSTRACT unclassified c . THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 1...Transform Fc : L2[−1, 1] → L2[−1, 1]; for a given c > 0, Fc of a function f ∈ L2[−1, 1] is defined by the formula: (Fc(f)) (ω) = ∫ 1 −1 e−ictωf(t)dt. (3...which can be found, for example, in [18]. Theorem 2.1. Suppose that the function K : [ c , d] × [a, b] → R is square integrable, and T : L2[a, b]→ L2[ c
On the Analytical and Numerical Properties of the Truncated Laplace Transform II
2015-05-29
applications in mathematics and engineering, it is useful to define the “Trun- cated” Fourier Transform Fc : L2[−1, 1] → L2[−1, 1]; for a given c > 0...following theorem, which can be found, for example, in [20]. Theorem 2.1. Suppose that the function K : [ c , d] × [a, b] → R is square integrable, and...T : L2[a, b] → L2[ c , d] is defined by the formula (T (f)) (x) = ∫ b a K(x, t)f(t)dt. (16) 3 Then, there exist two orthonormal sequences of functions
A Method of Evaluating Laplace Transforms with Series of Complete or Incomplete Beta Functions,
1982-12-01
4-4 - 014, .-4.--4 mf II II fI I Ii Ii It I Ig i i I I I m0 r0 e3 C)0 00 0 0 m0 00 n 0 00 n0 on n 03 0 - (r( _ r-’~ T0 0.0 (n~i m P0 "I NINI NJ3j...1010 100 a 0 Q 4’ 0 0 0-0’ .-4-4 (0 ’"t ( -4" N-N Itt -rj 4.4 tiI’ LM .-44 t-4 cm l (. N o I I ON4 ItLf’ co0 .or-4 -4.-4 In1. am NINI 0%m 0% N 1- 0
Solution of the General Helmholtz Equation Starting from Laplace’s Equation
2002-11-01
infinity for the two dimensional case. For the 3D the general form case, this term does not exist, as the potential at infinity is zero. Hence the Green’s...companies. She has assisted the Comisi6n the Living System Laboratory, Interministerial de Ciencia y Tecnologia (National LG Electronics, From 1998 to 2000
From Laplace to Supernova SN 1987A: Bayesian Inference in Astrophysics
NASA Astrophysics Data System (ADS)
Loredo, Thomas Joseph
1995-01-01
This dissertation describes the Bayesian approach to general problems of statistical inference in astrophysics, and then describes in detail the application of such methods to the analysis of the neutrinos detected from supernova SN 1987A in the Large Magellanic Cloud. Part I presents the Bayesian approach to probability theory as an alternative to the currently used long-run relative frequency approach, which does not offer clear, compelling criteria for the design of statistical methods. Bayesian probability theory offers unique and demonstrably optimal solutions to well-posed statistical problems, and is historically the original approach to statistics. After a brief historical introduction, we outline the Bayesian approaches to parameter estimation and model comparison and illustrate them by application to simple problems based on the Gaussian distribution. As further illustrations of the Bayesian paradigm, we outline Bayesian solutions to some simple astrophysical problems. Finally, we present a brief bibliography of astrophysically interesting applications of Bayesian inference. Part II presents an analysis of the detected energies and arrival times of the neutrinos from supernova SN 1987A detected by the Kamiokande II, IMB, and Baksan detectors. This work improves on previous studies in several important respects, including use of a consistent and straightforward statistical methodology, proper treatment of background rates, and consideration of a wider variety of neutrino emission models than was explored previously. We show that the inferred neutrino emission model parameters are strongly correlated. Consequently, best fit values and one-dimensional confidence intervals for the individual parameters do not adequately summarize the implications of the data. Our analysis confirms that simple models of the neutrino cooling of the nascent neutron star formed by the supernova adequately explain the data. The inferred characteristics of these models are in spectacular agreement with the salient features of the theory of stellar collapse and neutron star formation that had developed over several decades in the absence of direct observational data. We discuss the technical and conceptual differences between our analysis and previous analyses.
2011-02-21
procédures classiques par bases réduites offline-online peuvent alors être appliquées, donnant une complexité algorithmique online d’ordre O(N3 +Nnf...Des stratégies similaires offline-online peuvent aussi être employées pour le calcul de la borne d’erreur. La complexité algorithmique online est
NASA Astrophysics Data System (ADS)
Gregory, Roger B.; Zhu, Yongkang
1990-05-01
The performance of the program CONTIN [Stephen W. Provencher, Comput. Phys. Commun. 27 (1982) 229], modified to solve Fredholm integral equations with convoluted kernels of the type that occur in the deconvolution and analysis of positron annihilation lifetime data, is investigated with computer-simulated test data. The method avoids direct determination of the instrument resolution function by employing the decay curve of a reference material with a well-known single lifetime. CONTIN employs a constrained, regularized least-squares analysis to calculate a continuous annihilation-rate probability density function (pdf) which is the most parsimonious solution that is consistent with the experimental data and prior knowledge. The performance of the algorithm for extracting positron annihilation lifetime information was evaluated by using several measures of the information content of the data described by Schrader and Usmar [in: Positron Annihilation Studies of Fluids, ed. S. Sharma (World Scientific, Singapore, 1988) p. 215]. The quality of the CONTIN reconstruction of the annihilation-rate pdf is strongly dependent on the information content of the data and is greatly improved as the total number of counts in the data set is increased. Nevertheless, the method provides excellent estimates of the intensities and mean lifetimes of peaks in the annihilation-rate pdf, even when the total counts in the data set are relatively low (10 5-10 6). The sensitivity of the algorithm to systematic errors in the data, including errors in the instrument resolution function, shifts in the positron of the zero-time channel of the sample and reference data and contamination of the reference decay by additional lifetime components was also evaluated. Errors in the FWHM of the instrument resolution function and shifts in the zero time channel as small as {1}/{10}to{1}/{5} of the channel width of the instrument generate additional spurious peaks in the annihilation-rate pdf and introduce errors in the lifetime parameters of the short-lived components.
NASA Technical Reports Server (NTRS)
Pearson, E. M.; Halicioglu, T.; Tiller, W. A.
1985-01-01
A direct and convenient method is presented for deriving expressions which equate any thermodynamic state function to averages of specific dynamical functions and their fluctuations over the classical microcanonical distribution. Specific expressions are obtained for a variety of thermodynamic quantities. The effect of various entropy definitions on the results are assessed, and the latter are compared to previous work in the literature. The derived formulas are applied to the analysis of molecular-dynamics computer simulations.
The Resurrection of Laplace’s Method of Initial Orbit Determination
1983-01-17
astronomical techniques were suitably refined for these new problems with their new observables. The use of laser radars, beacon tracking, electro... lanets of antiquity were the above minus the Earth, plus the Moon and the Sun. I3 these lay in the plane of the ecliptic revolving about the Sun in...The 2’ following year Herschel discovers the first new planet in the history of the world and it fits the above scheme very well. This plus earlier
Courtney, Daniel G. Shea, Herbert
2015-09-07
Passively fed ionic liquid electrospray sources are capable of efficiently emitting a variety of ion beams with promising applications to spacecraft propulsion and as focused ion beams. Practical devices will require integrated or coupled ionic liquid reservoirs; the effects of which have not been explored in detail. Porous reservoirs are a simple, scalable solution. However, we have shown that their pore size can dramatically alter the beam composition. Emitting the ionic liquid 1-ethyl-3-methylimidazolium bis(triflouromethylsulfonyl)amide, the same device was shown to yield either an ion or droplet dominated beam when using reservoirs of small or large pore size, respectively; with the latter having a mass flow in excess of 15 times larger than the former at negative polarity. Another source, emitting nearly purely ionic beams of 1-ethyl-3-methylimidazolium tetrafluoroborate, was similarly shown to emit a significant droplet population when coupled to reservoirs of large (>100 μm) pores; constituting a reduction in propulsive efficiency from greater than 70% to less than 30%. Furthermore, we show that reservoir selection can alter the voltage required to obtain and sustain emission, increasing with smaller pore size.
Laplace and Z Transform Solutions of Differential and Difference Equations With the HP-41C.
ERIC Educational Resources Information Center
Harden, Richard C.; Simons, Fred O., Jr.
1983-01-01
A previously developed program for the HP-41C programmable calculator is extended to handle models of differential and difference equations with multiple eigenvalues. How to obtain difference equation solutions via the Z transform is described. (MNS)
Accelerating the shifted Laplace preconditioner for the Helmholtz equation by multilevel deflation
NASA Astrophysics Data System (ADS)
Sheikh, A. H.; Lahaye, D.; Garcia Ramos, L.; Nabben, R.; Vuik, C.
2016-10-01
Many important physical phenomena can be described by the Helmholtz equation. We investigate to what extent the convergence of the shifted Laplacian preconditioner for the Helmholtz equation can be accelerated using deflation with multigrid vectors. We therefore present a unified framework for two published algorithms. The first deflates the preconditioned operator and requires no further preconditioning. The second deflates the original operator and combines deflation and preconditioning in a multiplicative fashion. We pursue two scientific contributions. First we show, using a model problem analysis, that both algorithms cluster the eigenvalues. The new and key insight here is that the near-kernel of the coarse grid operator causes a limited set of eigenvalues to shift away from the center of the cluster with a distance proportional to the wave number. This effect is less pronounced in the first algorithmic variant at the expense of a higher computational cost. In the second contribution we quantify for the first time the large amount of reduction in CPU-time that results from the clustering of eigenvalues and the reduction in iteration count. We report to this end on the findings of an implementation in PETSc on two and three-dimensional problems with constant and variable wave number.
Study of Caking of Powders Using NQR Relaxometry with Inversion of the Laplace Transform
NASA Astrophysics Data System (ADS)
Sinyavsky, N. Ya.
2017-04-01
For the first time, it has been proposed to study the processes of caking nonmetallic powders containing quadrupole nuclei using the distribution of the spin-lattice and spin-spin relaxation times in NQR. The results of experimental studies of the effect of caking samples on the distributions of relaxation times of T1 and T2 for the 14N NQR in powders of NaNO2 and C6H12N4 are presented.
A wavelet-laplace variational technique for image deconvolution and inpainting.
Dobrosotskaya, Julia A; Bertozzi, Andrea L
2008-05-01
We construct a new variational method for blind deconvolution of images and inpainting, motivated by recent PDE-based techniques involving the Ginzburg-Landau functional, but using more localized wavelet-based methods. We present results for both binary and grayscale images. Comparable speeds are achieved with better sharpness of edges in the reconstruction.
Laplace operators of infinite-dimensional Lie algebras and theta functions.
Kac, V G
1984-01-01
Until recently, the generalized Casimir operator constructed by Kac [Kac, V. G. (1974) Funct. Anal. Appl. 8, 68-70] has been the only known element of the center of a completion of the enveloping algebra of a Kac-Moody algebra. It has been conjectured [Deodhar, V. V., Gabber, O. & Kac, V. G. (1982) Adv. Math. 45, 92-116], however, that the image of the Harish-Chandra homomorphism contains all theta functions defined on the interior of the complexified Tits cone and hence separates the orbits of the Weyl group. Developing the ideas of Feigin and Fuchs [Feigin, B. L. & Fuchs, D. B. (1983) Dokl. Akad. Nauk SSSR 269, 1057-1060], I prove this conjecture. Another application of this method is the Chevalley type restriction theorem for simple finite-dimensional Lie superalgebras.
The Rapid Solution of the Laplace Equation on Regions with Fractal Boundaries
1992-10-21
J. of Sci. and Stat. Comput., 12:79-94 (1991). [28] P. Henrici , Applied and Computational Complex Analysis, Vol. 1, Jonn Wiley & Sons, New York, 1974...29] P. Henrici , Applied and Computational Complex Analysis, Vol. 3, Jonn Wiley & Sons, New York, 1974. [30] H. G. Heuser, Functional Analysis, John
Heat trace for Laplace type operators with non-scalar symbols
NASA Astrophysics Data System (ADS)
Iochum, B.; Masson, T.
2017-06-01
For an elliptic selfadjoint operator P = - [uμν∂μ∂ν +vν∂ν + w ] acting on a fiber bundle over a compact Riemannian manifold, where uμν ,vμ , w are N × N-matrices, we develop a method to compute the heat-trace coefficients ar which allows to get them by a pure computational machinery. It is exemplified in any even dimension by the value of a1 written both in terms of uμν =gμν u ,vμ , w or diffeomorphic and gauge invariants. We also address the question: when is it possible to get explicit formulae for ar?
Laplace Operators of Infinite-Dimensional Lie Algebras and Theta Functions
NASA Astrophysics Data System (ADS)
Kac, Victor G.
1984-01-01
Until recently, the generalized Casimir operator constructed by Kac [Kac, V. G. (1974) Funct. Anal. Appl. 8, 68-70] has been the only known element of the center of a completion of the enveloping algebra of a Kac-Moody algebra. It has been conjectured [Deodhar, V. V., Gabber, O. & Kac, V. G. (1982) Adv. Math. 45, 92-116], however, that the image of the Harish-Chandra homomorphism contains all theta functions defined on the interior of the complexified Tits cone and hence separates the orbits of the Weyl group. Developing the ideas of Feigin and Fuchs [Feigin, B. L. & Fuchs, D. B. (1983) Dokl. Akad. Nauk SSSR 269, 1057-1060], I prove this conjecture. Another application of this method is the Chevalley type restriction theorem for simple finite-dimensional Lie superalgebras.
Crookshanks-Newman, F K; Belshe, R B
1986-02-01
Parainfluenza virus type 3 (para 3) was adapted to replicate at 20 degrees C, a nonpermissive temperature for wild-type (wt) para 3. Serial passage at 20 degrees C resulted in the generation of cold-adapted (ca) and temperature-sensitive (ts) mutants. These mutant viruses have been characterized both in vitro and in vivo [Belshe and Hissom (1982): Journal of Medical Virology 10:235-242; Crookshanks and Belshe (1984): Journal of Medical Virology 13:243-249]. We now report the evaluation of three mutants (clone 1150, passaged 12 times in the cold [cp12], clone 1146, passaged 18 times in the cold [cp18], and clone 1328, passaged 45 times in the cold [cp45]) for their ability to protect hamsters from infection by wild-type para 3. Ether-anesthetized male syrian hamsters were intranasally vaccinated with either wt para 3 (clone 127) or one of the ca para 3 mutants and on day 28 post-vaccination; each animal was intranasally challenged with 10(5.0) pfu of wt para 3. On days 1, 2, 3, and 4 post-challenge, 4 to 13 hamsters from each group were sacrificed, and the quantity of para 3 in the nasal turbinates and lungs was determined. Wt virus induced protection from challenge. cp12, cp18, and cp45 reduced the peak titer of wt replication in the lungs by greater than 100-fold, tenfold, and tenfold, respectively. The duration of virus replication was shortened also by intranasal vaccination with the mutants. These data give evidence of an inverse relationship between the degree of protection induced by vaccination with cold-adapted mutants and the number of passages of the virus in the cold.
DYNA3D/ParaDyn Regression Test Suite Inventory
Lin, J I
2011-01-25
The following table constitutes an initial assessment of feature coverage across the regression test suite used for DYNA3D and ParaDyn. It documents the regression test suite at the time of production release 10.1 in September 2010. The columns of the table represent groupings of functionalities, e.g., material models. Each problem in the test suite is represented by a row in the table. All features exercised by the problem are denoted by a check mark in the corresponding column. The definition of ''feature'' has not been subdivided to its smallest unit of user input, e.g., algorithmic parameters specific to a particular type of contact surface. This represents a judgment to provide code developers and users a reasonable impression of feature coverage without expanding the width of the table by several multiples. All regression testing is run in parallel, typically with eight processors. Many are strictly regression tests acting as a check that the codes continue to produce adequately repeatable results as development unfolds, compilers change and platforms are replaced. A subset of the tests represents true verification problems that have been checked against analytical or other benchmark solutions. Users are welcomed to submit documented problems for inclusion in the test suite, especially if they are heavily exercising, and dependent upon, features that are currently underrepresented.
Conformation of ionizable poly Para phenylene ethynylene in dilute solutions
Wijesinghe, Sidath; Maskey, Sabina; Perahia, Dvora; ...
2015-11-03
The conformation of dinonyl poly para phenylene ethynylenes (PPEs) with carboxylate side chains, equilibrated in solvents of different quality is studied using molecular dynamics simulations. PPEs are of interest because of their tunable electro-optical properties, chemical diversity, and functionality which are essential in wide range of applications. The polymer conformation determines the conjugation length and their assembly mode and affects electro-optical properties which are critical in their current and potential uses. The current study investigates the effect of carboxylate fraction on PPEs side chains on the conformation of chains in the dilute limit, in solvents of different quality. The dinonylmore » PPE chains are modeled atomistically, where the solvents are modeled both implicitly and explicitly. Dinonyl PPEs maintained a stretched out conformation up to a carboxylate fraction f of 0.7 in all solvents studied. The nonyl side chains are extended and oriented away from the PPE backbone in toluene and in implicit good solvent whereas in water and implicit poor solvent, the nonyl side chains are collapsed towards the PPE backbone. Thus, rotation around the aromatic ring is fast and no long range correlations are seen within the backbone.« less
Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria
Ye, D.; Quensen, J.F.; Tiedje, J.M.
1995-06-01
When microorganisms eluted from upper Hudson River sediment were cultured without any substrate except polychlorobiphenyl (PCB)-free Hudson River sediment, methane formation was the terminal step of the anaerobic food chain. In sediments containing Aroclor 1242, addition of eubacterium-inhibiting antibiotics, which should have directly inhibited fermentative bacteria and thereby should have indirectly inhibited methanogens, resulted in no dechlorination activity or methane production. However, when substrates for methanogenic bacteria were provided along with the antibiotics (to free the methanogens from dependence on eubacteria), concomitant methane production and dechlorination of PCBs were observed. The dechlorination of Aroclor 1242 was from the para positions, a pattern distinctly different from, and more limited than, the pattern observed with untreated or pasteurized inocula. Both methane production and dechlorination in cultures amended with antibiotics plus methanogenic substrates were inhibited by 2-bromoethanesulfonic acid. These results suggest that the methanogenic bacteria are among the physiological groups capable of anaerobic dechlorination of PCBs, but that the dechlorination observed with methanogenic bacteria is less extensive than the dechlorination observed with more complex anaerobic consortia. 27 refs., 5 figs., 1 tab.
DYNA3D/ParaDyn Regression Test Suite Inventory
Lin, Jerry I.
2016-09-01
The following table constitutes an initial assessment of feature coverage across the regression test suite used for DYNA3D and ParaDyn. It documents the regression test suite at the time of preliminary release 16.1 in September 2016. The columns of the table represent groupings of functionalities, e.g., material models. Each problem in the test suite is represented by a row in the table. All features exercised by the problem are denoted by a check mark (√) in the corresponding column. The definition of “feature” has not been subdivided to its smallest unit of user input, e.g., algorithmic parameters specific to a particular type of contact surface. This represents a judgment to provide code developers and users a reasonable impression of feature coverage without expanding the width of the table by several multiples. All regression testing is run in parallel, typically with eight processors, except problems involving features only available in serial mode. Many are strictly regression tests acting as a check that the codes continue to produce adequately repeatable results as development unfolds; compilers change and platforms are replaced. A subset of the tests represents true verification problems that have been checked against analytical or other benchmark solutions. Users are welcomed to submit documented problems for inclusion in the test suite, especially if they are heavily exercising, and dependent upon, features that are currently underrepresented.
Para-hydrogen induced polarization in heterogeneous hydrogenationreactions
Koptyug, Igor V.; Kovtunov, Kirill; Burt, Scott R.; Anwar, M.Sabieh; Hilty, Christian; Han, Song-I; Pines, Alexander; Sagdeev, Renad Z.
2007-01-31
We demonstrate the creation and observation ofpara-hydrogen-induced polarization in heterogeneous hydrogenationreactions. Wilkinson's catalyst, RhCl(PPh3)3, supported on eithermodified silica gel or a polymer, is shown to hydrogenate styrene intoethylbenzene and to produce enhanced spin polarizations, observed throughNMR, when the reaction was performed with H2 gas enriched in the paraspinisomer. Furthermore, gaseous phase para-hydrogenation of propylene topropane with two catalysts, the Wilkinson's catalyst supported onmodified silica gel and Rh(cod)(sulfos) (cod = cycloocta-1,5-diene;sulfos) - O3S(C6H4)CH2C(CH2PPh2)3) supported on silica gel, demonstratesheterogeneous catalytic conversion resulting in large spin polarizations.These experiments serve as a direct verification of the mechanism ofheterogeneous hydrogenation reactions involving immobilized metalcomplexes and can be potentially developed into a practical tool forproducing catalyst-free fluids with highly polarized nuclear spins for abroad range of hyperpolarized NMR and MRI applications.
Para-nitrobenzyl esterases with enhanced activity in aqueous and nonaqueous media
Arnold, F.H.; Moore, J.C.
1999-05-25
A method is disclosed for isolating and identifying modified para-nitrobenzyl esterases which exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enzymes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase. 43 figs.
Para-nitrobenzyl esterases with enhanced activity in aqueous and nonaqueous media
Arnold, Frances H.; Moore, Jeffrey C.
1998-01-01
A method for isolating and identifying modified para-nitrobenzyl esterases which exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enzymes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase.
Para-nitrobenzyl esterases with enhanced activity in aqueous and nonaqueous media
Arnold, Frances H.; Moore, Jeffrey C.
1999-01-01
A method for isolating and identifying modified para-nitrobenzyl esterases which exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enzymes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase.
Para-nitrobenzyl esterases with enhanced activity in aqueous and nonaqueous media
Arnold, F.H.; Moore, J.C.
1998-04-21
A method is disclosed for isolating and identifying modified para-nitrobenzyl esterases. These enzymes exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enzymes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase. 43 figs.
Bourne, Godfrey R; Breden, Felix; Allen, Teresa C
2003-09-01
The first results of female preference and chosen male mating success in a new model organism, the pentamorphic livebearing fish, Poecilia parae, are presented. Poecilia parae is a relative of the guppy, P. reticulata, and is assumed to have similar reproductive behavior. We tested the hypothesis that P. parae females, like female guppies, prefer carotenoid colored males as mates. Here we show that the time a female spent with males was significantly greater for carotenoid coloration in red and yellow melanzona, but time with these two morphs did not differ. The preferred red and yellow males mated significantly more often with their choosing females than did the non-preferred blue and parae males. The few blue melanzona and parae males that mated did so without performing courtship displays. Some females mated with all phenotypes including immaculata males during open group trials. Female P. parae clearly preferred males with carotenoid coloration, thereby corroborating the hypothesis. Alternative male mating tactics by blue melanzona, parae, and immaculata morphs and promiscuous mating by females also resembled features of reproductive behaviors exhibited by guppies.
Quantum fluctuations increase the self-diffusive motion of para-hydrogen in narrow carbon nanotubes.
Kowalczyk, Piotr; Gauden, Piotr A; Terzyk, Artur P; Furmaniak, Sylwester
2011-05-28
Quantum fluctuations significantly increase the self-diffusive motion of para-hydrogen adsorbed in narrow carbon nanotubes at 30 K comparing to its classical counterpart. Rigorous Feynman's path integral calculations reveal that self-diffusive motion of para-hydrogen in a narrow (6,6) carbon nanotube at 30 K and pore densities below ∼29 mmol cm(-3) is one order of magnitude faster than the classical counterpart. We find that the zero-point energy and tunneling significantly smoothed out the free energy landscape of para-hydrogen molecules adsorbed in a narrow (6,6) carbon nanotube. This promotes a delocalization of the confined para-hydrogen at 30 K (i.e., population of unclassical paths due to quantum effects). Contrary the self-diffusive motion of classical para-hydrogen molecules in a narrow (6,6) carbon nanotube at 30 K is very slow. This is because classical para-hydrogen molecules undergo highly correlated movement when their collision diameter approached the carbon nanotube size (i.e., anomalous diffusion in quasi-one dimensional pores). On the basis of current results we predict that narrow single-walled carbon nanotubes are promising nanoporous molecular sieves being able to separate para-hydrogen molecules from mixtures of classical particles at cryogenic temperatures.
ERIC Educational Resources Information Center
Raval, Harini; McKenney, Susan; Pieters, Jules
2012-01-01
The appointment of para-professionals to overcome skill shortages and/or make efficient use of expensive resources is well established in both developing and developed countries. The present research concerns para-teachers in India. The literature on para-teachers is dominated by training for special needs settings, largely in developed societies.…
Irradiation of Pelvic and Para-Aortic Nodes in Carcinoma of the Cervix.
Rotman; Aziz; Eifel
1994-01-01
Extended-field irradiation offers a significant chance of cure for patients with para-aortic node metastases if pelvic disease can be controlled. Prognosis is best for patients with microscopic para-aortic disease or with a single enlarged node. Complications of extended-field irradiation can be minimized with careful radiation therapy technique that uses multiple fields and high-energy beams of 18 MV or greater and by avoiding transperitoneal surgical staging. Although the role of prophylactic para-aortic irradiation is still being defined, randomized trials suggest that extended fields do benefit some patients with locoregionally advanced disease.
Endovascular Treatment of a Ruptured Para-Anastomotic Aneurysm of the Abdominal Aorta
Sfyroeras, Giorgos S.; Lioupis, Christos Bessias, Nikolaos; Maras, Dimitris; Pomoni, Maria; Andrikopoulos, Vassilios
2008-07-15
We report a case of a ruptured para-anastomotic aortic aneurysm treated with implantation of a bifurcated stent-graft. A 72-year-old patient, who had undergone aortobifemoral bypass for aortoiliac occlusive disease 16 years ago, presented with a ruptured para-anastomotic aortic aneurysm. A bifurcated stent-graft was successfully deployed into the old bifurcated graft. This is the first report of a bifurcated stent-graft being placed through an 'end-to-side' anastomosed old aortobifemoral graft. Endovascular treatment of ruptured para-anastomotic aortic aneurysms can be accomplished successfully, avoiding open surgery which is associated with increased mortality and morbidity.
Measurement of the formaldehyde ortho to para ratio in three molecular clouds
NASA Technical Reports Server (NTRS)
Kahane, C.; Lucas, R.; Frerking, M. A.; Langer, W. D.; Encrenaz, P.
1984-01-01
Observations of ortho and para H2CO in two types of clouds, a warm cloud (Orion A) and two cold clouds (L183 and TMC1), are presented. The ortho to para ratio in Orion deduced from the H2(C-13)O data is about three, while that for TMC1 is about one and that for L183 is 1-2. The former value is in agreement with the value calculated from chemical models of ortho and para H2CO production. The values for the cold clouds are consistent with thermal equilibrium at a temperature slightly smaller than 10 K.
Barucca, Marco; Biscotti, Maria A; Olmo, Ettore; Canapa, Adriana
2006-03-15
The ParaHox gene cluster contains three homeobox genes, Gsx, Xlox and Cdx and has been demonstrated to be an evolutionary sister of the Hox gene cluster. Among deuterostomes the three genes are found in the majority of taxa, whereas among protostomes they have so far been isolated only in the phylum Sipuncula. We report the partial sequences of all three ParaHox genes in the polyplacophoran Nuttallochiton mirandus, the first species of the phylum Mollusca where all ParaHox genes have been isolated. This finding has phylogenetic implications for the phylum Mollusca and for its relationships with the other lophotrochozoan taxa.
Measurement of the formaldehyde ortho to para ratio in three molecular clouds
NASA Technical Reports Server (NTRS)
Kahane, C.; Lucas, R.; Frerking, M. A.; Langer, W. D.; Encrenaz, P.
1984-01-01
Observations of ortho and para H2CO in two types of clouds, a warm cloud (Orion A) and two cold clouds (L183 and TMC1), are presented. The ortho to para ratio in Orion deduced from the H2(C-13)O data is about three, while that for TMC1 is about one and that for L183 is 1-2. The former value is in agreement with the value calculated from chemical models of ortho and para H2CO production. The values for the cold clouds are consistent with thermal equilibrium at a temperature slightly smaller than 10 K.
Time is of the essence for ParaHox homeobox gene clustering
2013-01-01
ParaHox genes, and their evolutionary sisters the Hox genes, are integral to patterning the anterior-posterior axis of most animals. Like the Hox genes, ParaHox genes can be clustered and exhibit the phenomenon of colinearity - gene order within the cluster matching gene activation. Two new instances of ParaHox clustering provide the first examples of intact clusters outside chordates, with gene expression lending weight to the argument that temporal colinearity is the key to understanding clustering. See research articles: http://www.biomedcentral.com/1741-7007/11/68 and http://www.biomedcentral.com/1471-2148/13/129 PMID:23803337
Blood transfusion in the para-Bombay phenotype.
Lin-Chu, M; Broadberry, R E
1990-08-01
The H-deficient phenotypes found in Chinese so far, have all been secretors of soluble blood group substances in saliva. The corresponding isoagglutinin activity (e.g. anti-B in OB(Hm) persons) has been found to be weak in all cases. To determine the clinical significance of these weak isoagglutinins 51Cr red cell survival tests were performed on three OB(Hm) individuals transfused with small volumes (4 ml) of groups B and O RBC. Rapid destruction of most of the RBC occurred whether or not the isoagglutinins of the OB(Hm) individuals were indirect antiglobulin test (IAGT) reactive. When a larger volume (54 ml packed RBC) of group B cells (weakly incompatible by IAGT) was transfused to another OB(Hm) individual with IAGT active anti-HI, the survival of the transfused RBC was 93% at 24 h, with 30% of the RBC remaining in the circulation at 28 d in contrast to 76% as would be expected if the survival was normal. Therefore when whole units of blood of normal ABO blood groups, compatible by IAGT, are transfused, the survival is expected to be almost normal. These weak isoagglutinins may not be very clinically significant and we suggest that when para-Bombay blood is not available, the compatibility testing for OA(Hm) persons should be performed with group A and group O packed RBC; OB(Hm) with group B and group O packed RBC: OAB(Hm) with groups A, B, AB and O packed RBC. For cross matching, the indirect antiglobulin test by a prewarmed technique should be used.
Management of large para-esophageal hiatal hernias.
Collet, D; Luc, G; Chiche, L
2013-12-01
Para-esophageal hernias are relatively rare and typically occur in elderly patients. The various presenting symptoms are non-specific and often occur in combination. These include symptoms of gastro-esophageal reflux (GERD) in 26 to 70% of cases, microcytic anemia in 17 to 47%, and respiratory symptoms in 9 to 59%. Respiratory symptoms are not completely resolved by surgical intervention. Acute complications such as gastric volvulus with incarceration or strangulation are rare (estimated incidence of 1.2% per patient per year) but gastric ischemia leading to perforation is the main cause of mortality. Only patients with symptomatic hernias should undergo surgery. Prophylactic repair to prevent acute incarceration should only be undertaken in patients younger than 75 in good condition; surgical indications must be discussed individually beyond this age. The laparoscopic approach is now generally accepted. Resection of the hernia sac is associated with a lower incidence of recurrence. Repair of the hiatus can be reinforced with prosthetic material (either synthetic or biologic), but the benefit of prosthetic repair has not been clearly shown. Results of prosthetic reinforcement vary in different studies; it has been variably associated with four times fewer recurrences or with no measurable difference. A Collis type gastroplasty may be useful to lengthen a foreshortened esophagus, but no objective criteria have been defined to support this approach. The anatomic recurrence rate can be as high as 60% at 12years. But most recurrences are asymptomatic and do not affect the quality of life index. It therefore seems more appropriate to evaluate functional results and quality of life measures rather than to gauge success by a strict evaluation of anatomic hernia reduction.
NASA Astrophysics Data System (ADS)
Gaiolas, C.; Costa, A. P.; Santos Silva, M. J.; Belgacem, M. N.
2012-07-01
Cold-plasma-assisted treatment of additive-free hand sheet paper samples with styrene (ST), para-fluorostyrene (FST), para-fluoro-α-methylstyrene (FMST) and para-chloro-α-methylstyrene (ClMST) and para-bromostyrene (BrST) was studied and found that the grafting has occurred efficiently, as established by contact angle measurement. Thus, after solvent extraction of the modified substrates, in order to remove unbounded grafts, the contact angle value of a drop of water deposited at the surface of paper increased from 40° for unmodified substrate to 102, 99, 116, 100 and 107°, for ST-, FST- FMST-, ClMST- and BrST-treated samples, respectively, indicating that the surface has became totally hydrophobic. In fact, the polar component of the surface energy of treated samples decreased from 25 mJ/m2 to practically zero, indicating that treated surfaces were rendered totally non polar.
Successful Mnemonics for "por"/"para" and Affirmative Commands with Pronouns.
ERIC Educational Resources Information Center
Mason, Keith
1992-01-01
Two mnemonic devices, "4A Rule" and "PERFECT," are described to simplify the learning of two grammar points: the placement of object pronouns with respect to commands and the distinction between "por" and "para." (five references) (LB)
Genomic organisation of the seven ParaHox genes of coelacanths.
Mulley, John F; Holland, Peter W H
2014-09-01
Human and mouse genomes contain six ParaHox genes implicated in gut and neural patterning. In coelacanths and cartilaginous fish, an additional ParaHox gene exists-Pdx2-that dates back to the genome duplications in early vertebrate evolution. Here we examine the genomic arrangement and flanking genes of all ParaHox genes in coelacanths, to determine the full complement of these genes. We find that coelacanths have seven ParaHox genes in total, in four chromosomal locations, revealing that five gene losses occurred soon after vertebrate genome duplication. Comparison of intergenic sequences reveals that some Pdx1 regulatory regions associated with development of pancreatic islets are older than tetrapods, that Pdx1 and Pdx2 share few if any conserved non-coding elements, and that there is very high sequence conservation between coelacanth species.
Lampreys, the jawless vertebrates, contain only two ParaHox gene clusters.
Zhang, Huixian; Ravi, Vydianathan; Tay, Boon-Hui; Tohari, Sumanty; Pillai, Nisha E; Prasad, Aravind; Lin, Qiang; Brenner, Sydney; Venkatesh, Byrappa
2017-08-22
ParaHox genes (Gsx, Pdx, and Cdx) are an ancient family of developmental genes closely related to the Hox genes. They play critical roles in the patterning of brain and gut. The basal chordate, amphioxus, contains a single ParaHox cluster comprising one member of each family, whereas nonteleost jawed vertebrates contain four ParaHox genomic loci with six or seven ParaHox genes. Teleosts, which have experienced an additional whole-genome duplication, contain six ParaHox genomic loci with six ParaHox genes. Jawless vertebrates, represented by lampreys and hagfish, are the most ancient group of vertebrates and are crucial for understanding the origin and evolution of vertebrate gene families. We have previously shown that lampreys contain six Hox gene loci. Here we report that lampreys contain only two ParaHox gene clusters (designated as α- and β-clusters) bearing five ParaHox genes (Gsxα, Pdxα, Cdxα, Gsxβ, and Cdxβ). The order and orientation of the three genes in the α-cluster are identical to that of the single cluster in amphioxus. However, the orientation of Gsxβ in the β-cluster is inverted. Interestingly, Gsxβ is expressed in the eye, unlike its homologs in jawed vertebrates, which are expressed mainly in the brain. The lamprey Pdxα is expressed in the pancreas similar to jawed vertebrate Pdx genes, indicating that the pancreatic expression of Pdx was acquired before the divergence of jawless and jawed vertebrate lineages. It is likely that the lamprey Pdxα plays a crucial role in pancreas specification and insulin production similar to the Pdx of jawed vertebrates.
1983-12-22
IN TRANS ATION ~TITLE: .SPANISH COASTAL PATROL SHIPS FOR ARGENTINA AND MEXICO GUARDACOSTAS EFPANOLES PARA ARGENTINA Y MEJICO AUTHOR: M; RAMIREZ...SHIPS FOR ARGENTINA AND MEXICO [Ramirez Gabarrus, M.; Guardacostas espaioles para Argentina y Mejico; Tecnologia Militar, No. 4, 1983; pP. 50, 53-54... Mexico , Mr. Alvarez de Vayo, signed a contract with the Mexican War Minister, General Cardenas, to build a series of 10 coastal patrol boats and five
Chordate Hox and ParaHox gene clusters differ dramatically in their repetitive element content.
Osborne, Peter W; Ferrier, David E K
2010-02-01
The ParaHox and Hox gene clusters control aspects of animal anterior-posterior development and are related as paralogous evolutionary sisters. Despite this relationship, it is not clear if the clusters operate in similar ways, with similar constraints. To compare clusters, we examined the transposable-element (TE) content of amphioxus and mammalian ParaHox and Hox clusters. Chordate Hox clusters are known to be largely devoid of TEs, possibly due to gene regulation and constraints on clustering in these animals. Here, we describe several novel amphioxus TEs and show that the amphioxus ParaHox cluster is a hotspot for TE insertion. TE contents of mammalian ParaHox loci are at background levels, in stark contrast to chordate Hox clusters. This marks a significant difference between Hox and ParaHox clusters. The presence of so many potentially disruptive elements implies selection constrains these ParaHox clusters as they have not dispersed despite 500 My of evolution for each lineage.
para-C-H Borylation of Benzene Derivatives by a Bulky Iridium Catalyst.
Saito, Yutaro; Segawa, Yasutomo; Itami, Kenichiro
2015-04-22
A highly para-selective aromatic C-H borylation has been accomplished. By a new iridium catalyst bearing a bulky diphosphine ligand, Xyl-MeO-BIPHEP, the C-H borylation of monosubstituted benzenes can be affected with para-selectivity up to 91%. This catalytic system is quite different from the usual iridium catalysts that cannot distinguish meta- and para-C-H bonds of monosubstituted benzene derivatives, resulting in the preferred formation of meta-products. The para-selectivity increases with increasing bulkiness of the substituent on the arene, indicating that the regioselectivity of the present reaction is primarily controlled by steric repulsion between substrate and catalyst. Caramiphen, an anticholinergic drug used in the treatment of Parkinson's disease, was converted into five derivatives via our para-selective borylation. The present [Ir(cod)OH]2/Xyl-MeO-BIPHEP catalyst represents a unique, sterically controlled, para-selective, aromatic C-H borylation system that should find use in streamlined, predictable chemical synthesis and in the rapid discovery and optimization of pharmaceuticals and materials.
Diffusion Monte Carlo Study of Para-Diiodobenzene Polymorphism Revisited.
Hongo, Kenta; Watson, Mark A; Iitaka, Toshiaki; Aspuru-Guzik, Alán; Maezono, Ryo
2015-03-10
We revisit our investigation of the diffusion Monte Carlo (DMC) simulation of para-diiodobenzene (p-DIB) molecular crystal polymorphism. [See J. Phys. Chem. Lett. 2010, 1, 1789-1794.] We perform, for the first time, a rigorous study of finite-size effects and choice of nodal surface on the prediction of polymorph stability in molecular crystals using fixed-node DMC. Our calculations are the largest that are currently feasible using the resources of the K-computer and provide insights into the formidable challenge of predicting such properties from first principles. In particular, we show that finite-size effects can influence the trial nodal surface of a small (1 × 1 × 1) simulation cell considerably. Therefore, we repeated our DMC simulations with a 1 × 3 × 3 simulation cell, which is the largest such calculation to date. We used a density functional theory (DFT) nodal surface generated with the PBE functional, and we accumulated statistical samples with ∼6.4 × 10(5) core hours for each polymorph. Our final results predict a polymorph stability that is consistent with experiment, but they also indicate that the results in our previous paper were somewhat fortuitous. We analyze the finite-size errors using model periodic Coulomb (MPC) interactions and kinetic energy corrections, according to the CCMH scheme of Chiesa, Ceperley, Martin, and Holzmann. We investigate the dependence of the finite-size errors on different aspect ratios of the simulation cell (k-mesh convergence) in order to understand how to choose an appropriate ratio for the DMC calculations. Even in the most expensive simulations currently possible, we show that the finite size errors in the DMC total energies are much larger than the energy difference between the two polymorphs, although error cancellation means that the polymorph prediction is accurate. Finally, we found that the T-move scheme is essential for these massive DMC simulations in order to circumvent population explosions and
The PARA-suite: PAR-CLIP specific sequence read simulation and processing
Kloetgen, Andreas; Borkhardt, Arndt; Hoell, Jessica I.
2016-01-01
Background Next-generation sequencing technologies have profoundly impacted biology over recent years. Experimental protocols, such as photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation (PAR-CLIP), which identifies protein–RNA interactions on a genome-wide scale, commonly employ deep sequencing. With PAR-CLIP, the incorporation of photoactivatable nucleosides into nascent transcripts leads to high rates of specific nucleotide conversions during reverse transcription. So far, the specific properties of PAR-CLIP-derived sequencing reads have not been assessed in depth. Methods We here compared PAR-CLIP sequencing reads to regular transcriptome sequencing reads (RNA-Seq) to identify distinctive properties that are relevant for reference-based read alignment of PAR-CLIP datasets. We developed a set of freely available tools for PAR-CLIP data analysis, called the PAR-CLIP analyzer suite (PARA-suite). The PARA-suite includes error model inference, PAR-CLIP read simulation based on PAR-CLIP specific properties, a full read alignment pipeline with a modified Burrows–Wheeler Aligner algorithm and CLIP read clustering for binding site detection. Results We show that differences in the error profiles of PAR-CLIP reads relative to regular transcriptome sequencing reads (RNA-Seq) make a distinct processing advantageous. We examine the alignment accuracy of commonly applied read aligners on 10 simulated PAR-CLIP datasets using different parameter settings and identified the most accurate setup among those read aligners. We demonstrate the performance of the PARA-suite in conjunction with different binding site detection algorithms on several real PAR-CLIP and HITS-CLIP datasets. Our processing pipeline allowed the improvement of both alignment and binding site detection accuracy. Availability The PARA-suite toolkit and the PARA-suite aligner are available at https://github.com/akloetgen/PARA-suite and https://github.com/akloetgen/PARA
Spontaneous Emission Between - and Para-Levels of Water-Ion H_2O^+
NASA Astrophysics Data System (ADS)
Tanaka, Keiichi; Harada, Kensuke; Nanbu, Shinkoh; Oka, Takeshi
2012-06-01
Nuclear spin conversion interaction of water ion, H_2O^+, has been studied to derive spontaneous emission lifetime between ortho- and para-levels. H_2O^+ is a radical ion with the ^2B_1 electronic ground state. Its off-diagonal electron spin-nuclear spin interaction term, Tab(S_aΔ I_b + S_bΔ I_a), connects para and ortho levels, because Δ I = I_1 - I_2 has nonvanishing matrix elements between I = 0 and 1. The mixing by this term with Tab = 72 MHz predicted by ab initio theory in the MRD-CI/Bk level, is many orders of magnitude larger than for closed shell molecules because of the large magnetic interaction due to the un-paired electron. Using the molecular constants reported by Mürtz et al. by FIR-LMR, we searched for ortho and para coupling channels below 1000 cm-1 with accidental near degeneracy between para and ortho levels. For example, hyperfine components of the 42,2(ortho) and 33,0(para) levels mix by 1.2 × 10-3 due to their near degeneracy (Δ E = 0.417 cm-1), and give the ortho-para spontaneous emission lifetime of about 0.63 year. The most significant low lying 10,1(para) and 11,1(ortho) levels, on the contrary, mix only by 8.7 × 10-5 because of their large separation (Δ E = 16.267 cm-1) and give the spontaneous emission lifetime from 10,1(para) to 00,0(ortho) of about 100 year.These results qualitatively help to understand the observed high ortho- to para- H_2O^+ ratio of 4.8 ± 0.5 toward Sgr B2 but they are too slow to compete with the conversion by collision unless the number density of the region is very low (n ˜1 cm-3) or radiative temperature is very high (T_r > 100 K). M. Staikova, B. Engels, M. Peric, and S.D. Peyerimhoff, Mol. Phys. 80, 1485 (1993) P. Mürtz, L.R. Zink, K.M. Evenson, and J.M. Brown J. Chem. Phys. 109, 9744 (1998). LP. Schilke, et al., A&A 521, L11 (2010).
Vesicular erythema multiforme-like reaction to para-phenylenediamine in a henna tattoo.
Sidwell, Rachel U; Francis, Nick D; Basarab, Tamara; Morar, Nilesh
2008-01-01
Allergic contact dermatitis reaction to topical "black henna" tattoo is usually described secondary to the organic dye para-phenylenediamine, a derivative of analine. Allergic contact dermatitis reactions to para-phenylenediamine are well recognized and most commonly involve an eczematous reaction that may become generalized and an acute angio-edema. Only four previous instances have been reported of an erythema multiforme-like reaction to para-phenylenediamine and its derivatives, including only one mild reaction to a tattoo. A vesicular erythema multiforme-like reaction has not been reported. An erythema multiforme-like reaction to contact allergens is usually caused by potent allergens including plant quinolones in Compositae and sesquiterpene lactones in exotic woods, and it is also reported to topical drugs, epoxy resin, metals (particularly nickel), and various chemicals. A generalized vesicular erythema multiforme-like reaction is unusual, and rarely reported. We describe a 6-year-old boy who developed a localized, eczematous and severe generalized vesicular erythema multiforme-like contact allergy to para-phenylenediamine secondary to a henna tattoo. As henna tattoos are becoming increasingly popular, one should be aware of the possibility of such a reaction. This presentation also highlights the call to ban the use of para-phenylenediamine and its derivatives in dyes.
Estimation of Carbon Storage in Para Rubber Plantation in Eastern Thailand
NASA Astrophysics Data System (ADS)
Charoenjit, K.; Zuddas, P.; Allemand, P.
2012-12-01
This study aims to estimate the carbon stock and sequestration in Para rubber plantation of East Thailand using the THAICHOTE (Thailand Earth Observation System data). For that purpose we identify the area of every stage class Para rubber plantation by the analysis of different image objects (i.e., rule base and multiple regression classifications) and we map the carbon stock and sequestration of each Para rubber class using biomass allometric regressions and carbon content equations. THAICHOTE data include Multispectral image (4 bands at 15x15 m spatial resolution), Panchromatic image (2x2 m spatial resolution) and Stereo image, data acquisition from December 2011-April 2012. The preliminary investigated area is located in Wangchun, (Eastern, Thailand) and covers about 20 Km2. Calibrating the class stage, by image analysis that integrated edge-based segmentation, reflectance, remote sensing indices, texture analysis and canopy height model (CHM), we found that best classification was obtained by multiple regression (accuracy of 80%) compared to rule base logical operation (accuracy 70%) suggesting that manual 3D stereo measurements or Light Detection And Ranging (LiDAR) both are able to construct the CHM. The results of this study indicate that for a total Para rubber biomass of 14,651 tons, the amount of stored carbon is of 7,326 tons. Mature stage of Para rubber plantations exhibits the highest capacity of sequestering with a global flux of 0.21 tons C/ Km2/year.
The ortho/para ratio of water vapor in Comet Halley
NASA Technical Reports Server (NTRS)
Mumma, Michael J.; Larson, Harold P.; Weaver, Harold A.
1986-01-01
The ortho/para ratio of H2O is shown to be an invariant in the cometary coma. The dependence of ortho-para ratio on temperature in thermal equilibrium is given, and the nuclear-spin-temperature is defined. Its relation to the physical temperature of the cometary ices is discussed, and the prospects for using the observed ortho/para ratio to infer properties of the cometary nucleus are explored. The ortho/para ratio in Halley's comet is derived from high resolution infrared spectra of near 2.7 microns wavelength. On UT December 24.1, 1985 it was 2.73 + or - 0.17, and on UT March 22.7, 1986 it was 3.23 + or - 0.37. The nuclear-spin-temperature was 35 K (+9 K, -5 K) pre-perihelion, and less than 40 K post-perihelion, at the 67% confidence limit. Both numbers are consistent with modeled values of the equilibrium temperature of the cometary nucleus at aphelion (47 K). However, at the 95% confidence limit they are also fully consistent with temperatures less than 50 K, corresponding to an ortho/para ratio of about 3.0.
The formaldehyde ortho/para ratio as a probe of dark cloud chemistry and evolution
NASA Technical Reports Server (NTRS)
Dickens, J. E.; Irvine, W. M.
1999-01-01
We present measurements of the H2CO ortho/para ratio toward four star-forming cores, L723, L1228, L1527, and L43, and one quiescent core, L1498. Combining these data with earlier results by Minh et al., three quiescent cores are found to have ortho/para ratios near 3, the ratio of statistical weights expected for gas-phase formation processes. In contrast, ortho/para ratios are 1.5-2.1 in five star-forming cores, suggesting thermalization at a kinetic temperature of 10 K. We attribute modification of the ortho/para ratio in the latter cores to formation and/or equilibration of H2CO on grains with sub-sequent release back into the gas phase due to the increased energy inputs from the forming star and outflow. We see accompanying enhancements in the H2CO abundance relative to H, to support this idea. The results suggest that the formaldehyde ortho/para ratio can differentiate between quiescent cores and those in which low-mass star formation has occurred.
Influence of Molecular Oxygen on Ortho-Para Conversion of Water Molecules
NASA Astrophysics Data System (ADS)
Valiev, R. R.; Minaev, B. F.
2017-07-01
The mechanism of influence of molecular oxygen on the probability of ortho-para conversion of water molecules and its relation to water magnetization are considered within the framework of the concept of paramagnetic spin catalysis. Matrix elements of the hyperfine ortho-para interaction via the Fermi contact mechanism are calculated, as well as the Maliken spin densities on water protons in H2O and O2 collisional complexes. The mechanism of penetration of the electron spin density into the water molecule due to partial spin transfer from paramagnetic oxygen is considered. The probability of ortho-para conversion of the water molecules is estimated by the quantum chemistry methods. The results obtained show that effective ortho-para conversion of the water molecules is possible during the existence of water-oxygen dimers. An external magnetic field affects the ortho-para conversion rate given that the wave functions of nuclear spin sublevels of the water protons are mixed in the complex with oxygen.
The formaldehyde ortho/para ratio as a probe of dark cloud chemistry and evolution
NASA Technical Reports Server (NTRS)
Dickens, J. E.; Irvine, W. M.
1999-01-01
We present measurements of the H2CO ortho/para ratio toward four star-forming cores, L723, L1228, L1527, and L43, and one quiescent core, L1498. Combining these data with earlier results by Minh et al., three quiescent cores are found to have ortho/para ratios near 3, the ratio of statistical weights expected for gas-phase formation processes. In contrast, ortho/para ratios are 1.5-2.1 in five star-forming cores, suggesting thermalization at a kinetic temperature of 10 K. We attribute modification of the ortho/para ratio in the latter cores to formation and/or equilibration of H2CO on grains with sub-sequent release back into the gas phase due to the increased energy inputs from the forming star and outflow. We see accompanying enhancements in the H2CO abundance relative to H, to support this idea. The results suggest that the formaldehyde ortho/para ratio can differentiate between quiescent cores and those in which low-mass star formation has occurred.
Sistemas Correctores de Campo Para EL Telescopio Ritchey-Chretien UNAM212
NASA Astrophysics Data System (ADS)
Cobos, F. J.; Galan, M. J.
1987-05-01
El telescopio UNAM2l2 fue inaugurado hace siete años y concebido para trabajar en las razones focales: f/7.5, F/13.5, F/27 y F/98. El diseño Ritchey-Chretién corresponde a la razón focal F/7.5 y el foco primario (F/2.286) no se consideró como utilizable para fotografía directa. En el Instituto de Astronomía de la UNAM, se diseñó y construyó un sistema corrector de campo para la razón focal F/7.5, que actualmente está en funcionamiento. Dentro de un programa de colaboración en diseflo y evaluación de sistemas ópticos, entre el Instituto de Astrofísica de Canarias y el Instituto de Astronomía de la UNAM, decidimos intentar el diseño de una correctora de campo para el foco primario del tȩlescopio UNAM212 bajo la consideración de que no son insalvables los problemas que implicaría su instalación y de que es muy posible que, en un futuro relativamente cercano, podamom tener un detector bidimenmional tipo Mepsicrón cuya área sensible haga tentadora la idea de construir la cámara directa para foco primario
Modelos Teoricos de Linhas de Recombinacao EM Radio Frequencias Para Regioes H II
NASA Astrophysics Data System (ADS)
Abraham, Z.; Cancoro, A. C. O.
1987-05-01
Foram feitos modelos de linhas de recombinção provenientes de regiões HII nas frequências de rádio para distintos números quãnticos. Estes modelos consideram regrões H II esfericamente simétricas com variações radiais na densidade e temperatura eletrônica, efeitos de colisoes inelásticas dos eletrons (alargarnento por pressão), e afastarnento do equiliíbrio termodinâmico local. 0 bojetivo é construir o perfil da linha para cada ponto da nuvern e obter o valor médio resultante da sua convoluçã com o feixe da antena de tarnanho comparável corn o tarnanho angular da nuvern para posterIor cornpara o corn
Allergic contact dermatitis to para-phenylenediamine in a tattoo: a case report.
Turan, Hakan; Okur, Mesut; Kaya, Ertugrul; Gun, Emrah; Aliagaoglu, Cihangir
2013-06-01
It is highly popular among children and young adults to have temporary henna tattoos on their bodies in different colors and figures. Henna is a greenish natural powder obtained from the flowers and dry leaves of Lawsonia alba plant and its allergenicity is very low. Henna is also used in combination with other coloring substances such as para-phenylenediamine in order to darken the color and create a permanent tattoo effect. Para-phenylenediamine is a substance with high allergenicity potential and may cause serious allergic reactions. Here, we aimed to draw attention to the potential harms of para-phenylenediamine containing temporary tattoos by presenting a child patient who developed allergic contact dermatitis after having a scorpion-shaped temporary tattoo on his forearm.
The School of Posture as a postural training method for Paraíba Telecommunications Operators.
Cardia, M C; Soares Màsculo, F
2001-01-01
This work proposes to show the experience of posture training accomplished in the Paraíba State Telecommunication Company, using the knowledge of the Back School. The sample was composed of 12 operators, employees of the company, representing 31% of this population. The model applied in TELPA (Paraíba Telecommunication Company, Brazil) was based on the models of Sherbrooke, Canada, and of the School of Posture of Paraìba Federal University. Fifty-eight point four percent of participants showed a reduction of column pain, 25% improved the quality of the rest and the received training was considered enough for the learning of correct postures at work in 75% of the cases. The whole population approved of the training, and 83.3% of the cases considered that this training influenced their lives very positively.
Sobre la terapia génica para enfermedades de la retina.
Fischer, M Dominik
2017-07-11
Las mutaciones en un gran número de genes provocan degeneración de la retina y ceguera sin que exista actualmente cura alguna. En las últimas décadas, la terapia génica para enfermedades de la retina ha evolucionado y se ha convertido en un nuevo y prometedor paradigma terapéutico para estas enfermedades poco comunes. Este artículo refleja las ideas y los conceptos que parten de la ciencia básica hacia la aplicabilidad de la terapia génica en el ámbito clínico. Se describen los avances y las reflexiones actuales sobre la eficacia de los ensayos clínicos en la actualidad y se discuten los posibles obstáculos y soluciones de cara al futuro de la terapia génica para enfermedades de la retina. © 2017 S. Karger AG, Basel.
Complications of pelvic and para-aortic lymphadenectomy in patients with endometrial cancer.
Arduino, S; Leo, L; Febo, G; Tessarolo, M; Wierdis, T; Lanza, A
1997-01-01
The International Federation of Gynecology and Obstetrics (FIGO) changed the staging criteria for endometrial cancer in 1988 and adopted a surgical-pathological staging involving also pelvic and/or para-aortic lymphadenectomy. A total of 236 patients were treated for endometrial adenocarcinoma at Department B of the Gynecologic and Obstetrics Institute, University of Turin, between January 1976 and December 1995. Our protocol for surgical staging always entails pelvic and para-aortic lymphadenectomy and a simple total hysterectomy and bilateral adnexectomy with removal of the upper third of the vagina. The aim of this study was to carry out a retrospective evaluation of the morbidity in patients with endometrial cancer after surgical treatment, either TAH-BSO alone or TAH-BSO with pelvic and para-aortic lymphadenectomy.
Production and characterization of para-hydrogen gas for matrix isolation infrared spectroscopy
NASA Astrophysics Data System (ADS)
Sundararajan, K.; Sankaran, K.; Ramanathan, N.; Gopi, R.
2016-08-01
Normal hydrogen (n-H2) has 3:1 ortho/para ratio and the production of enriched para-hydrogen (p-H2) from normal hydrogen is useful for many applications including matrix isolation experiments. In this paper, we describe the design, development and fabrication of the ortho-para converter that is capable of producing enriched p-H2. The p-H2 thus produced was probed using infrared and Raman techniques. Using infrared measurement, the thickness and the purity of the p-H2 matrix were determined. The purity of p-H2 was determined to be >99%. Matrix isolation infrared spectra of trimethylphosphate (TMP) and acetylene (C2H2) were studied in p-H2 and n-H2 matrices and the results were compared with the conventional inert matrices.
Evidence for disequilibrium of ortho and para hydrogen on Jupiter from Voyager IRIS measurements
NASA Technical Reports Server (NTRS)
Conrath, B. J.; Gierasch, P. J.
1983-01-01
Preliminary results of an analysis of the ortho state/para state ratio (parallel/antiparallel) for molecular H2 in the Jovian atmosphere using Voyager IR spectrometer (IRIS) data are reported. The study was undertaken to expand the understanding of the thermodynamics of a predominantly H2 atmosphere, which takes about 100 million sec to reach equilibrium. IRIS data provided 4.3/cm resolution in the 300-700/cm spectral range dominated by H2 lines. Approximately 600 spectra were examined to detect any disequilibrium between the hydrogen species. The results indicate that the ortho-para ratio is not in an equilibrium state in the upper Jovian troposphere. A thorough mapping of the para-state molecules in the upper atmosphere could therefore aid in mapping the atmospheric flowfield.
Evidence for disequilibrium of ortho and para hydrogen on Jupiter from Voyager IRIS measurements
NASA Technical Reports Server (NTRS)
Conrath, B. J.; Gierasch, P. J.
1983-01-01
Preliminary results of an analysis of the ortho state/para state ratio (parallel/antiparallel) for molecular H2 in the Jovian atmosphere using Voyager IR spectrometer (IRIS) data are reported. The study was undertaken to expand the understanding of the thermodynamics of a predominantly H2 atmosphere, which takes about 100 million sec to reach equilibrium. IRIS data provided 4.3/cm resolution in the 300-700/cm spectral range dominated by H2 lines. Approximately 600 spectra were examined to detect any disequilibrium between the hydrogen species. The results indicate that the ortho-para ratio is not in an equilibrium state in the upper Jovian troposphere. A thorough mapping of the para-state molecules in the upper atmosphere could therefore aid in mapping the atmospheric flowfield.
Electrical detection of ortho-para conversion in fullerene-encapsulated water
NASA Astrophysics Data System (ADS)
Meier, Benno; Mamone, Salvatore; Concistrè, Maria; Alonso-Valdesueiro, Javier; Krachmalnicoff, Andrea; Whitby, Richard J.; Levitt, Malcolm H.
2015-08-01
Water exists in two spin isomers, ortho and para, that have different nuclear spin states. In bulk water, rapid proton exchange and hindered molecular rotation obscure the direct observation of two spin isomers. The supramolecular endofullerene H2O@C60 provides freely rotating, isolated water molecules even at cryogenic temperatures. Here we show that the bulk dielectric constant of this substance depends on the ortho/para ratio, and changes slowly in time after a sudden temperature jump, due to nuclear spin conversion. The attribution of the effect to ortho-para conversion is validated by comparison with nuclear magnetic resonance and quantum theory. The change in dielectric constant is consistent with an electric dipole moment of 0.51+/-0.05 Debye for an encapsulated water molecule, indicating the partial shielding of the water dipole by the encapsulating cage. The dependence of bulk dielectric constant on nuclear spin isomer composition appears to be a previously unreported physical phenomenon.
Identificación de Intervenciones para el Desarrollo Positivo de la Juventud
Sardiñas, Lili M.; Padilla, Viviana; Aponte, Mari; Boscio, Ana Morales; Pedrogo, Coralee Pérez; Santiago, Betzaida; Morales, Ángela Pérez; Dávila, Paloma Torres; Cesáreo, Marizaida Sánchez
2017-01-01
Resumen En el mundo hay más personas en la etapa de la juventud que en cualquier otra etapa del desarrollo. La juventud en Puerto Rico enfrenta muchas situaciones que inciden en su desarrollo y preparación para la adultez. Por lo tanto, es imperante identificar intervenciones para el desarrollo positivo de la juventud que han demostrado ser basadas en la evidencia. Además, a partir de dicha identificación, desarrollar prácticas que ayuden a los jóvenes a desarrollarse para prevenir situaciones adversas, promover experiencias positivas y propiciar que los niños y jóvenes estén involucrados y comprometidos. Se identificaron 147 intervenciones a través de una revisión tradicional de la literatura científica estadounidense. Los resultados reflejan que las intervenciones atienden la reducción de factores de riesgo y el incremento de factores de protección. Sin embargo, ninguna intervención propicia que los niños y jóvenes estén involucrados y comprometidos con su desarrollo óptimo y con sus comunidades. No obstante, todas brindan herramientas que podrían ser de utilidad para fomentar dichas prácticas en el contexto de Puerto Rico. De las 147 intervenciones identificadas seis están diseñadas para la población puertorriqueña residente en la Isla. Con el propósito de hacer la información accesible a los profesionales y la comunidad se expandió la colección del Archivo de Programas y Prácticas Basadas en Evidencia para la Prevención. PMID:28919943
Bonano, J S; Banks, M L; Kolanos, R; Sakloth, F; Barnier, M L; Glennon, R A; Cozzi, N V; Partilla, J S; Baumann, M H; Negus, S S
2015-01-01
Background and Purpose Methcathinone (MCAT) is a potent monoamine releaser and parent compound to emerging drugs of abuse including mephedrone (4-CH3 MCAT), the para-methyl analogue of MCAT. This study examined quantitative structure–activity relationships (QSAR) for MCAT and six para-substituted MCAT analogues on (a) in vitro potency to promote monoamine release via dopamine and serotonin transporters (DAT and SERT, respectively), and (b) in vivo modulation of intracranial self-stimulation (ICSS), a behavioural procedure used to evaluate abuse potential. Neurochemical and behavioural effects were correlated with steric (Es), electronic (σp) and lipophilic (πp) parameters of the para substituents. Experimental Approach For neurochemical studies, drug effects on monoamine release through DAT and SERT were evaluated in rat brain synaptosomes. For behavioural studies, drug effects were tested in male Sprague-Dawley rats implanted with electrodes targeting the medial forebrain bundle and trained to lever-press for electrical brain stimulation. Key Results MCAT and all six para-substituted analogues increased monoamine release via DAT and SERT and dose- and time-dependently modulated ICSS. In vitro selectivity for DAT versus SERT correlated with in vivo efficacy to produce abuse-related ICSS facilitation. In addition, the Es values of the para substituents correlated with both selectivity for DAT versus SERT and magnitude of ICSS facilitation. Conclusions and Implications Selectivity for DAT versus SERT in vitro is a key determinant of abuse-related ICSS facilitation by these MCAT analogues, and steric aspects of the para substituent of the MCAT scaffold (indicated by Es) are key determinants of this selectivity. PMID:25438806
Calcisponges have a ParaHox gene and dynamic expression of dispersed NK homeobox genes.
Fortunato, Sofia A V; Adamski, Marcin; Ramos, Olivia Mendivil; Leininger, Sven; Liu, Jing; Ferrier, David E K; Adamska, Maja
2014-10-30
Sponges are simple animals with few cell types, but their genomes paradoxically contain a wide variety of developmental transcription factors, including homeobox genes belonging to the Antennapedia (ANTP) class, which in bilaterians encompass Hox, ParaHox and NK genes. In the genome of the demosponge Amphimedon queenslandica, no Hox or ParaHox genes are present, but NK genes are linked in a tight cluster similar to the NK clusters of bilaterians. It has been proposed that Hox and ParaHox genes originated from NK cluster genes after divergence of sponges from the lineage leading to cnidarians and bilaterians. On the other hand, synteny analysis lends support to the notion that the absence of Hox and ParaHox genes in Amphimedon is a result of secondary loss (the ghost locus hypothesis). Here we analysed complete suites of ANTP-class homeoboxes in two calcareous sponges, Sycon ciliatum and Leucosolenia complicata. Our phylogenetic analyses demonstrate that these calcisponges possess orthologues of bilaterian NK genes (Hex, Hmx and Msx), a varying number of additional NK genes and one ParaHox gene, Cdx. Despite the generation of scaffolds spanning multiple genes, we find no evidence of clustering of Sycon NK genes. All Sycon ANTP-class genes are developmentally expressed, with patterns suggesting their involvement in cell type specification in embryos and adults, metamorphosis and body plan patterning. These results demonstrate that ParaHox genes predate the origin of sponges, thus confirming the ghost locus hypothesis, and highlight the need to analyse the genomes of multiple sponge lineages to obtain a complete picture of the ancestral composition of the first animal genome.
Superfluid Effects in PARA-H_2 Clusters Probed by CO_2 Rotation-Vibration Transitions
NASA Astrophysics Data System (ADS)
Li, Hui; Le Roy, Robert J.; Roy, Pierre-Nicholas; McKellar, A. R. W.
2010-06-01
The prospect of directly observing superfluidity in para-H_2 is a tantalizing but elusive goal. Like ^4He, para-H_2 is a light zero-spin boson. However, H_2-H_2 intermolecular interactions, though weak, are stronger than He-He interactions, and hydrogen is a solid below about 14 K. This makes detection of superfluidity in bulk hydrogen problematical, to say the least. But there are still possibilities for para-H_2 in the form of clusters or in nano-confined environments, and superfluid transition temperatures as high as ˜6 K have been predicted. Spectroscopic observations of (para-H_2)_N-CO_2 clusters were at first very difficult to interpret for N > 5. However, with the help of path integral Monte Carlo simulations and an accurate new H_2-CO_2 intermolecular potential surface which explicitly incorporates dependence on the CO_2 νb{3} asymmetric stretch, it is now possible to achieve a remarkably consistent picture of (para-H_2)_N-CO_2 clusters in the size range N = 1 ˜ 20. By combining the experimental spectroscopic measurements and theoretical simulations, we determine the size evolution of the superfluid response of the CO_2-doped para-H_2 clusters, which peaks for the "magic" number N = 12. V. L. Ginzburg and A. A. Sobyanin, JETP Lett. 15, 343 (1972). A. R. W. McKellar, Paper WH04, 63rd OSU International Symposium on Molecular Spectroscopy, June 16-20, 2008. H. Li, P.-N. Roy, and R. J. Le Roy, J. Chem. Phys., submitted.
Evaluation of an immobilized cell bioreactor for degradation of meta- and para-nitrobenzoate
NASA Astrophysics Data System (ADS)
Peretti, Steven W.; Thomas, Stuart M.
1994-01-01
Meta- and para-nitrobenzoic acid are pollutants found in waste streams from metal-stripping processes using cyanide-free solvents. The Kelly AFB industrial Waste Treatment Plant (IWTP) is currently incapable of removing these compounds from its wastewaters because of the presence of significant quantities of ethylenediamine, a preferred substrate and upper limit of 4-5 hours on the hydraulic residence time in the IWTP. This report describes the enrichment and preliminary characterization of a microbial consortium capable of utilizing both Meta- and Para-Nitrobenzoate as sole carbon sources.
Quantum rotation of ortho and para-water encapsulated in a fullerene cage
Beduz, Carlo; Carravetta, Marina; Chen, Judy Y.-C.; Concistrè, Maria; Denning, Mark; Frunzi, Michael; Horsewill, Anthony J.; Johannessen, Ole G.; Lawler, Ronald; Lei, Xuegong; Levitt, Malcolm H.; Li, Yongjun; Mamone, Salvatore; Murata, Yasujiro; Nagel, Urmas; Nishida, Tomoko; Ollivier, Jacques; Rols, Stéphane; Rõõm, Toomas; Sarkar, Riddhiman; Turro, Nicholas J.; Yang, Yifeng
2012-01-01
Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation and ortho–para conversion of single water molecules trapped inside closed fullerene cages. The existence of metastable ortho-water molecules is demonstrated, and the interconversion of ortho-and para-water spin isomers is tracked in real time. Our investigation reveals that the ground state of encapsulated ortho water has a lifted degeneracy, associated with symmetry-breaking of the water environment. PMID:22837402
Experiments at Scale with In-Situ Visualization Using ParaView/Catalyst in RAGE
Kares, Robert John
2014-10-31
In this paper I describe some numerical experiments performed using the ParaView/Catalyst in-situ visualization infrastructure deployed in the Los Alamos RAGE radiation-hydrodynamics code to produce images from a running large scale 3D ICF simulation on the Cielo supercomputer at Los Alamos. The detailed procedures for the creation of the visualizations using ParaView/Catalyst are discussed and several images sequences from the ICF simulation problem produced with the in-situ method are presented. My impressions and conclusions concerning the use of the in-situ visualization method in RAGE are discussed.
Quantum rotation of ortho and para-water encapsulated in a fullerene cage.
Beduz, Carlo; Carravetta, Marina; Chen, Judy Y-C; Concistrè, Maria; Denning, Mark; Frunzi, Michael; Horsewill, Anthony J; Johannessen, Ole G; Lawler, Ronald; Lei, Xuegong; Levitt, Malcolm H; Li, Yongjun; Mamone, Salvatore; Murata, Yasujiro; Nagel, Urmas; Nishida, Tomoko; Ollivier, Jacques; Rols, Stéphane; Rõõm, Toomas; Sarkar, Riddhiman; Turro, Nicholas J; Yang, Yifeng
2012-08-07
Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation and ortho-para conversion of single water molecules trapped inside closed fullerene cages. The existence of metastable ortho-water molecules is demonstrated, and the interconversion of ortho-and para-water spin isomers is tracked in real time. Our investigation reveals that the ground state of encapsulated ortho water has a lifted degeneracy, associated with symmetry-breaking of the water environment.
ERIC Educational Resources Information Center
Marcato, Carla
1997-01-01
Describes and analyzes the language of young people in Italy today. Particular focus is on the expressions using "para" (e.g., "in para totale" = to be very bored or worried) and the phrase "una cosa da panico" (something terrible or its opposite something wonderful). (CFM)
ERIC Educational Resources Information Center
Marcato, Carla
1997-01-01
Describes and analyzes the language of young people in Italy today. Particular focus is on the expressions using "para" (e.g., "in para totale" = to be very bored or worried) and the phrase "una cosa da panico" (something terrible or its opposite something wonderful). (CFM)
[Fut1 gene mutation for para-bombay blood type individual in Fujian Province of China].
Huang, Hao-Bou; Fan, Li-Ping; Wai, Shi-Jin; Zeng, Feng; Lin, Hai-Yan; Zhang, Rong
2010-10-01
This study was aimed to investigate the molecular mechanisms for para-Bombay blood type individual in Fujian Province of China. The para-Bombay blood type of this individual was identified by routine serological techniques. The full coding region of alpha (1,2) fucosyltransferase (FUT1) gene of this individual was amplified by polymerase chain reaction (PCR), then the PCR product was cloned into T vector. The mutation in coding region of fut1 gene was identified by TA cloning, so as to explore the molecular mechanisms for para-Bombay blood type individual. The results indicated that the full coding region of fut1 gene was successfully amplified by PCR. AG deletion at position 547-552 on 2 homologous chromosomes was detected by TA cloning method, leading to a reading frame shift and a premature stop codon. It is concluded that genetic mutation of fut1 gene in this para-bombay blood type individual was h1h1 homozygotic type.
Performance characteristics of magnesium/para-nitrophenol cells in 2:1 magnesium electrolytes
Kumar, G.; Sivashanugam, A.; Sridharan, R. )
1993-11-01
1 V/1 Ah magnesium/para-nitrophenol (PNP) reserve cells were fabricated and their performance was evaluated in different electrolytes [2M aqueous solutions of Mg(C1O[sub 4])[sub 2], MgCl[sub 2], and MgBr[sub 2
Factor Structure of the "Escala de Autoeficacia para la Depresion en Adolescentes" (EADA)
ERIC Educational Resources Information Center
Diaz-Santos, Mirella; Cumba-Aviles, Eduardo; Bernal, Guillermo; Rivera-Medina, Carmen
2011-01-01
The current concept and measures of self-efficacy for depression in adolescents do not consider developmental and cultural aspects essential to understand and assess this construct in Latino youth. We examined the factor structure of the "Escala de Autoeficacia para la Depresion en Adolescentes" (EADA), a Spanish instrument designed to…
Factor Structure of the "Escala de Autoeficacia para la Depresion en Adolescentes" (EADA)
ERIC Educational Resources Information Center
Diaz-Santos, Mirella; Cumba-Aviles, Eduardo; Bernal, Guillermo; Rivera-Medina, Carmen
2011-01-01
The current concept and measures of self-efficacy for depression in adolescents do not consider developmental and cultural aspects essential to understand and assess this construct in Latino youth. We examined the factor structure of the "Escala de Autoeficacia para la Depresion en Adolescentes" (EADA), a Spanish instrument designed to…
Para-Professionals in Further Education: Changing Roles in Vocational Delivery
ERIC Educational Resources Information Center
Scott, Gill
2005-01-01
Roles and structures within further education colleges seem to be in constant change and development; roles are becoming blurred, and lecturers are taking on more management tasks. Alongside this has been the development of para-professional roles, using non-lecturers to undertake teaching tasks. This can allow for the greater involvement of…
Ortho-para conversion of endohedral water in the fullerene C60 at cryogenic temperatures
NASA Astrophysics Data System (ADS)
Shugai, Anna; Nagel, U.; Rõõm, T.; Mamone, S.; Concistrè, M.; Meier, B.; Krachmalnicoff, A.; Whitby, R. J.; Levitt, M. H.; Lei, Xuegong; Li, Yongjun; Turro, N. J.
2015-03-01
Water displays the phenomenon of spin isomerism in which the two proton spins either couple to form a triplet (ortho water, I = 1) or a singlet nuclear spin state (para water, I = 0). Here we study the interconversion of para and ortho water. The exact mechanism of this process is still not fully understood. In order to minimize interactions between molecules we use a sample where a single H2O is trapped in the C60 molecular cage (H2O@C60)andH2O@C60iscrystallized.H2O@C60 has long-lived ortho state and ortho-para conversion kinetics is non-exponential at LHeT. We studied mixtures of H2O@C60, D2O@C60 and C60 using IR absorption, NMR and dielectric measurements. We saw the speeding up of the interconversion with the growth of H2O@C60 concentration in C60 or when D2O@C60 was added. At some temperatures the kinetics is exponential. Models are discussed in order to explain the T and concentration dependence of ortho-para interconversion kinetics. This work was supported by institutional research funding IUT23-3 of the Estonian Ministry of Education and Research.
Autoguía para el telescopio 2,15 mts de CASLEO
NASA Astrophysics Data System (ADS)
Aballay, J. A.; Casagrande, A. R.; Pereyra, P. F.; Marún, A. H.
Se está desarrollando un sistema de autoguía para el telescopio de 2,15 mts. El mismo se realizará aprovechando el Offset Guider. Al ocular móvil de éste se vinculará alguna cámara digital (ST4-ST7-CH250) para lograr la visión del objeto. El funcionamiento del equipo será el siguiente: primero, dadas las coordenadas del objeto a observar, se tomarán las coordenadas del telescopio para que, a través de una base de datos, se determine un campo de objetos que sirvan para la cámara de visión, luego, la PC obtendrá el offset entre la estrella de observación y la estrella seleccionada como guía, este valor será trasladado a los motores que posicionarán en forma automática el ocular. Una vez que la estrella es visualizada en la cámara (monitor de PC ) se correrá el programa que guiará el telescopio automáticamente.
UPLC-ESI-MS/MS analysis of Sudan dyes and Para Red in food.
Li, C; Wu, Y L; Shen, J Z
2010-09-01
An analytical method for the simultaneous determination of Sudan dyes (Sudan Red G, Sudan I, Sudan II, Sudan III, Sudan Red 7B and Sudan IV) and Para Red in food by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) was developed. Samples were extracted with acetonitrile, and water added into the extract. The supernatant was analysed by UPLC-MS/MS after refrigeration and centrifugation. The sample was separated on an Acquity BEH C(18) column, and detected by MS/MS with the multiple reaction monitoring mode. Matrix calibration was used for quantitative testing of the method. The linear matrix calibrations of Sudan dyes and Para Red were 2-50 and 10-250 ng g(-1), respectively, and the regression coefficients were >0.9945. The recoveries were 83.4-112.3% with good coefficients of variation of 2.0-10.8%. The limits of detection were between 0.3 and 1.4 ng g(-1) for the six Sudan dyes, and between 3.7 and 6.0 ng g(-1) for Para Red. The limits of quantification were between 0.9 and 4.8 ng g(-1) for the six Sudan dyes, and between 12.2 and 19.8 ng g(-1) for Para Red.
Can para-aryl-dithiols cross-link two plasmonic noble nanoparticles as monolayer dithiolate spacers
USDA-ARS?s Scientific Manuscript database
Para-aryl-dithiols (PADTs, HS-(C6H4)n-SH, n = 1, 2, and 3) have been used extensively in molecular electronics, surface-enhanced Raman spectroscopy (SERS), and quantum electron tunneling between two gold or silver nanoparticles (AuNPs and AgNPs). One popular belief is that these dithiols cross-link ...
An Analysis of Interlanguage Development Over Time: Part 1, "por" and "para".
ERIC Educational Resources Information Center
Guntermann, Gail
1992-01-01
The first part of a larger planned investigation, this study examines the use of "por" and "para" by nine Peace Corps volunteers in oral interviews at the end of training and roughly one year later, to trace their acquisition over time, in two learning contexts. (24 references) (LB)
ERIC Educational Resources Information Center
Lafford, Barbara A.; Ryan, John M.
1995-01-01
Examination of the development of form/function relations of the prepositions "por" and "para" at different levels of proficiency in the interlanguage of study-abroad students in Granada, Spain, revealed "noncanonical" as well as "canonical" uses of these prepositions. The most common noncanonical uses were…
Energia Renovable para Centros de Salud Rurales (Renewable Energy for Rural Health Clinics)
Jimenez, T.; Olson, K.
1999-07-28
Esta es la primera de una serie de guias de aplicaciones que el Programa de Energia de Villas de NREL esta comisionando para acoplar sistemas comerciales renovables con aplicaciones rurales, incluyendo agua, escuelas rurales y micro empresas. La guia esta complementada por las actividades de desarrollo del Programa de Energia de Villas de NREL, proyectos pilotos internacionales y programas de visitas profesionales.
ERIC Educational Resources Information Center
Paolantonio, Mario Di
2011-01-01
Recently, a few buildings within the "Espacio para la memoria" in Buenos Aires have been designated as a UNESCO Centre where, amongst other educational activities, evidentiary materials of the past repression are to be stored and displayed. Another building in the complex houses a Community Centre operated by the Mothers of the Plaza de…
Irradiation of para-aortic lymph node metastases from carcinoma of the cervix or endometrium
Komaki, R.; Mattingly, R.F.; Hoffman, R.G.; Barber, S.W.; Satre, R.; Greenberg, M.
1983-04-01
Twenty-two patients with biopsy-proved para-aortic lymph node metastases from carcinoma of the cervix (15 patients) or endometrium (7 patients) received a median dose of 5,000 rad/25 fractions. Para-aortic nodal metastases were controlled in 77% of cases. Control was significantly lower following radical retroperitoneal lymph node dissection than less extensive sampling procedures. Obstruction of the small bowel developed in 3 patients with tumor recurrence in the para-aortic region. Eight of the 10 patients who were disease-free at 2 years received >5,000 rad. Three patients were still alive without disease at 129, 63, and 60 months, respectively. The 5-year disease-free survival rate was 40% for cervical cancer and 60% for endometrial cancer: in the former group, it was significantly different depending on whether the para-aortic nodes were irradiated (40%) or not (0%). The authors suggest that 5,000-5,500 rad in 5-5.5 weeks is well tolerated and can control aortic nodal metastases in cervical and possibly endometrial cancer.
ERIC Educational Resources Information Center
Paolantonio, Mario Di
2011-01-01
Recently, a few buildings within the "Espacio para la memoria" in Buenos Aires have been designated as a UNESCO Centre where, amongst other educational activities, evidentiary materials of the past repression are to be stored and displayed. Another building in the complex houses a Community Centre operated by the Mothers of the Plaza de…
Anuncios de servicio público para proteger a los trabajadores de plaguicidas
Estos archivos de anuncios de servicio público se pueden descargar libremente para su uso en la formación, transmisiones de audio, etc.(These public service announcement files can be freely downloaded for use in training, audio broadcasts, etc.)
Malík, Ivan; Bukovský, Marián; Andriamainty, Fils; Gališinová, Jana
2013-01-01
In current research, nine basic esters of para-alkoxyphenylcarbamic acid with incorporated 4-(4-fluoro-/3-trifluoromethylphenyl)piperazin-1-yl fragment, 6i–6m and 8f–8i, were screened for their in vitro antimicrobial activity against Candida albicans, Staphylococcus aureus and Escherichia coli, respectively. Taking into account the minimum inhibitory concentration assay (MIC), as the most active against given yeast was evaluated 8i (MIC = 0.20 mg/mL), the most lipophilic structure containing para-butoxy and trifluoromethyl substituents. Investigating the efficiency of the compounds bearing only a single atom of fluorine and appropriate para-alkoxy side chain against Candida albicans, the cut-off effect was observed. From evaluated homological series, the maximum of the effectiveness was noticed for the stucture 6 k (MIC = 0.39 mg/mL), containing para-propoxy group attached to phenylcarbamoyloxy fragment, beyond which the compounds ceased to be active. On the contrary, all the tested molecules were against Staphylococcus aureus and Escherichia coli (MICs > 1.00 mg/mL) practically inactive. PMID:24294237
Fabrication and Evaluation of New Resins. Volume 1. Synthesis of Para- Ordered Aromatic Polymers
1978-04-01
identify by block number) Para-ordered Polymers Polybenzobisthiazoles Poly (diphenylbenzobisimidazoles) Polybenzobisoxazoles Thermally Stable Polymers...linear polybenzobisoxazole (PBO) , but with improved solubility, higher molecular weight, and increased thermooxidative stability. PBO PBO is soluble to...order to develop high strength in the oriented film or fiber this molecular weight may have to be increased. Although the thermooxidative stability of
Development of High-Activity Para- to Ortho-Hydrogen Conversion Catalysts. Volume 2
1989-09-28
and Loeb1, E. M., J. Phys. Chem. 73, 894 (1969). G. C. Michael , Ph.D. thesis, The Pennsylvania State Univ., University Park, 1969. Misono, M., and...hydrogen. Zhavoronkova, K. N.; Peshkov, A. V.; Spivak ,, N. A. Tr. - M’osk. Khim.-Tekhnol. Inst. im. 0. I. Mendeleeva, 99, 89-92 (1978). Ortho-para
NASA Astrophysics Data System (ADS)
Mishra, Piyush; Hewett, Daniel M.; Zwier, Timothy S.
2017-06-01
This talk focuses on the single-conformation spectroscopy of small-chain para-dialkylbenzenes. This work builds on previous studies from our group on long-chain n-alkylbenzenes that identified the first folded structure in octylbenzene. The dialkylbenzenes are representative of a class of molecules that are common components of coal and aviation fuel and are known to be present in vehicle exhaust. We bring the molecules para-diethylbenzene, para-dipropylbenzene and para-dibutylbenzene into the gas phase and cool the molecules in a supersonic expansion. The jet-cooled molecules are then interrogated using laser-induced fluorescence excitation, fluorescence dip IR spectroscopy (FDIRS) and dispersed fluorescence. The LIF spectra in the S_{0}-S_{1} origin region show dramatic increases in the number of resolved transitions with increasing length of alkyl chains, reflecting an explosion in the number of unique low-energy conformations formed when two independent alkyl chains are present. Since the barriers to isomerization of the alkyl chain are similar in size, this results in an 'egg carton' shape to the potential energy surface. We use a combination of electronic frequency shift and alkyl CH stretch infrared spectra to generate a consistent set of conformational assignments.
Vínculos observacionais para o processo-S em estrelas gigantes de Bário
NASA Astrophysics Data System (ADS)
Smiljanic, R. H. S.; Porto de Mello, G. F.; da Silva, L.
2003-08-01
Estrelas de bário são gigantes vermelhas de tipo GK que apresentam excessos atmosféricos dos elementos do processo-s. Tais excessos são esperados em estrelas na fase de pulsos térmicos do AGB (TP-AGB). As estrelas de bário são, no entanto, menos massivas e menos luminosas que as estrelas do AGB, assim, não poderiam ter se auto-enriquecido. Seu enriquecimento teria origem em uma estrela companheira, inicialmente mais massiva, que evolui pelo TP-AGB, se auto-enriquece com os elementos do processo-s e transfere material contaminado para a atmosfera da atual estrela de bário. A companheira evolui então para anã branca deixando de ser observada diretamente. As estrelas de bário são, portanto, úteis como testes observacionais para teorias de nucleossíntese pelo processo-s, convecção e perda de massa. Análises detalhadas de abundância com dados de alta qualidade para estes objetos são ainda escassas na literatura. Neste trabalho construímos modelos de atmosferas e, procedendo a uma análise diferencial, determinamos parâmetros atmosféricos e evolutivos de uma amostra de dez gigantes de bário e quatro normais. Determinamos seus padrões de abundância para Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu e Gd, concluindo que algumas estrelas classificadas na literatura como gigantes de bário são na verdade gigantes normais. Comparamos dois padrões médios de abundância, para estrelas com grandes excessos e estrelas com excessos moderados, com modelos teóricos de enriquecimento pelo processo-s. Os dois grupos de estrelas são ajustados pelos mesmos parâmetros de exposição de nêutrons. Tal resultado sugere que a ocorrência do fenômeno de bário com diferentes intensidades não se deve a diferentes exposições de nêutrons. Discutimos ainda efeitos nucleossintéticos, ligados ao processo-s, sugeridos na literatura para os elementos Cu, Mn, V e Sc.
Mothcakes made of para-dichlorobenzene have been widely available for the general population to be used as a moth repellant to protect garments from insect damage. Usually, a mothcake is expected to last for weeks or even months during which the para-dichlorobenzene emits slowly ...
Mothcakes made of para-dichlorobenzene have been widely available for the general population to be used as a moth repellant to protect garments from insect damage. Usually, a mothcake is expected to last for weeks or even months during which the para-dichlorobenzene emits slowly ...
Hox and ParaHox gene expression in early body plan patterning of polyplacophoran mollusks
Fritsch, Martin; Wollesen, Tim
2016-01-01
ABSTRACT Molecular developmental studies of various bilaterians have shown that the identity of the anteroposterior body axis is controlled by Hox and ParaHox genes. Detailed Hox and ParaHox gene expression data are available for conchiferan mollusks, such as gastropods (snails and slugs) and cephalopods (squids and octopuses), whereas information on the putative conchiferan sister group, Aculifera, is still scarce (but see Fritsch et al., 2015 on Hox gene expression in the polyplacophoran Acanthochitona crinita). In contrast to gastropods and cephalopods, the Hox genes in polyplacophorans are expressed in an anteroposterior sequence similar to the condition in annelids and other bilaterians. Here, we present the expression patterns of the Hox genes Lox5, Lox4, and Lox2, together with the ParaHox gene caudal (Cdx) in the polyplacophoran A. crinita. To localize Hox and ParaHox gene transcription products, we also investigated the expression patterns of the genes FMRF and Elav, and the development of the nervous system. Similar to the other Hox genes, all three Acr‐Lox genes are expressed in an anteroposterior sequence. Transcripts of Acr‐Cdx are seemingly present in the forming hindgut at the posterior end. The expression patterns of both the central class Acr‐Lox genes and the Acr‐Cdx gene are strikingly similar to those in annelids and nemerteans. In Polyplacophora, the expression patterns of the Hox and ParaHox genes seem to be evolutionarily highly conserved, while in conchiferan mollusks these genes are co‐opted into novel functions that might have led to evolutionary novelties, at least in gastropods and cephalopods. PMID:27098677
Hox and ParaHox gene expression in early body plan patterning of polyplacophoran mollusks.
Fritsch, Martin; Wollesen, Tim; Wanninger, Andreas
2016-03-01
Molecular developmental studies of various bilaterians have shown that the identity of the anteroposterior body axis is controlled by Hox and ParaHox genes. Detailed Hox and ParaHox gene expression data are available for conchiferan mollusks, such as gastropods (snails and slugs) and cephalopods (squids and octopuses), whereas information on the putative conchiferan sister group, Aculifera, is still scarce (but see Fritsch et al., 2015 on Hox gene expression in the polyplacophoran Acanthochitona crinita). In contrast to gastropods and cephalopods, the Hox genes in polyplacophorans are expressed in an anteroposterior sequence similar to the condition in annelids and other bilaterians. Here, we present the expression patterns of the Hox genes Lox5, Lox4, and Lox2, together with the ParaHox gene caudal (Cdx) in the polyplacophoran A. crinita. To localize Hox and ParaHox gene transcription products, we also investigated the expression patterns of the genes FMRF and Elav, and the development of the nervous system. Similar to the other Hox genes, all three Acr-Lox genes are expressed in an anteroposterior sequence. Transcripts of Acr-Cdx are seemingly present in the forming hindgut at the posterior end. The expression patterns of both the central class Acr-Lox genes and the Acr-Cdx gene are strikingly similar to those in annelids and nemerteans. In Polyplacophora, the expression patterns of the Hox and ParaHox genes seem to be evolutionarily highly conserved, while in conchiferan mollusks these genes are co-opted into novel functions that might have led to evolutionary novelties, at least in gastropods and cephalopods.
Ancient origins of axial patterning genes: Hox genes and ParaHox genes in the Cnidaria.
Finnerty, J R; Martindale, M Q
1999-01-01
Among the bilaterally symmetrical, triploblastic animals (the Bilateria), a conserved set of developmental regulatory genes are known to function in patterning the anterior-posterior (AP) axis. This set includes the well-studied Hox cluster genes, and the recently described genes of the ParaHox cluster, which is believed to be the evolutionary sister of the Hox cluster (Brooke et al. 1998). The conserved role of these axial patterning genes in animals as diverse as frogs and flies is believed to reflect an underlying homology (i.e., all bilaterians derive from a common ancestor which possessed an AP axis and the developmental mechanisms responsible for patterning the axis). However, the origin and early evolution of Hox genes and ParaHox genes remain obscure. Repeated attempts have been made to reconstruct the early evolution of Hox genes by analyzing data from the triphoblastic animals, the Bilateria (Schubert et al. 1993; Zhang and Nei 1996). A more precise dating of Hox origins has been elusive due to a lack of sufficient information from outgroup taxa such as the phylum Cnidaria (corals, hydras, jellyfishes, and sea anemones). In combination with outgroup taxa, another potential source of information about Hox origins is outgroup genes (e.g., the genes of the ParaHox cluster). In this article, we present cDNA sequences of two Hox-like genes (anthox2 and anthox6) from the sea anemone, Nematostella vectensis. Phylogenetic analysis indicates that anthox2 (= Cnox2) is homologous to the GSX class of ParaHox genes, and anthox6 is homologous to the anterior class of Hox genes. Therefore, the origin of Hox genes and ParaHox genes occurred prior to the evolutionary split between the Cnidaria and the Bilateria and predated the evolution of the anterior-posterior axis of bilaterian animals. Our analysis also suggests that the central Hox class was invented in the bilaterian lineage, subsequent to their split from the Cnidaria.
Rotational excitation of HCN by para- and ortho-H{sub 2}
Vera, Mario Hernández; Kalugina, Yulia; Denis-Alpizar, Otoniel; Stoecklin, Thierry; Lique, François
2014-06-14
Rotational excitation of the hydrogen cyanide (HCN) molecule by collisions with para-H{sub 2}( j = 0, 2) and ortho-H{sub 2}( j = 1) is investigated at low temperatures using a quantum time independent approach. Both molecules are treated as rigid rotors. The scattering calculations are based on a highly correlated ab initio 4-dimensional (4D) potential energy surface recently published. Rotationally inelastic cross sections among the 13 first rotational levels of HCN were obtained using a pure quantum close coupling approach for total energies up to 1200 cm{sup −1}. The corresponding thermal rate coefficients were computed for temperatures ranging from 5 to 100 K. The HCN rate coefficients are strongly dependent on the rotational level of the H{sub 2} molecule. In particular, the rate coefficients for collisions with para-H{sub 2}( j = 0) are significantly lower than those for collisions with ortho-H{sub 2}( j = 1) and para-H{sub 2}( j = 2). Propensity rules in favor of even Δj transitions were found for HCN in collisions with para-H{sub 2}( j = 0) whereas propensity rules in favor of odd Δj transitions were found for HCN in collisions with H{sub 2}( j ⩾ 1). The new rate coefficients were compared with previously published HCN-para-H{sub 2}( j = 0) rate coefficients. Significant differences were found due the inclusion of the H{sub 2} rotational structure in the scattering calculations. These new rate coefficients will be crucial to improve the estimation of the HCN abundance in the interstellar medium.
Wagner, Shawn
2014-06-01
To determine the storability of para-hydrogen before reestablishment of the room temperature thermal equilibrium mixture. Para-hydrogen was produced at near 100% purity and mixed with different oxygen quantities to determine the rate of conversion to the thermal equilibrium mixture of 75: 25% (ortho: para) by detecting the ortho-hydrogen (1)H nuclear magnetic resonance using a 9.4 T imager. The para-hydrogen to ortho-hydrogen velocity constant, k, near room temperature (292 K) was determined to be 8.27 ± 1.30 L/mol · min(-1). This value was calculated utilizing four different oxygen fractions. Para-hydrogen conversion to ortho-hydrogen by oxygen can be minimized for long term storage with judicious removal of oxygen contamination. Prior calculated velocity rates were confirmed demonstrating a dependence on only the oxygen concentration.
NASA Astrophysics Data System (ADS)
Tuttle, William Duncan; Gardner, Adrian M.; Whalley, Laura E.; Wright, Timothy G.
2017-06-01
We have employed resonance-enhanced multiphoton ionisation (REMPI) spectroscopy and zero-kinetic-energy (ZEKE) spectroscopy to investigate the first excited electronic singlet (S_{1}) state and the cationic ground state (D_{0}^{+}) of para-fluorotoluene (pFT) and para-xylene (pXyl). Spectra have been recorded via a large number of selected intermediate levels, to support assignment of the vibration and vibration-torsion levels in these molecules and to investigate possible couplings. The study of levels in this region builds upon previous work on the lower energy regions of pFT and pXyl and here we are interested in how vibration-torsion (vibtor) levels might combine and interact with vibrational ones, and so we consider the possible couplings which occur. Comparisons between the spectra of the two molecules show a close correspondence, and the influence of the second methyl rotor in para-xylene on the onset of intramolecular vibrational redistribution (IVR) in the S_{1} state is a point of interest. This has bearing on future work which will need to consider the role of both more flexible side chains of substituted benzene molecules, and multiple side chains. A. M. Gardner, W. D. Tuttle, L. Whalley, A. Claydon, J. H. Carter and T. G. Wright, J. Chem. Phys., 145, 124307 (2016). A. M. Gardner, W. D. Tuttle, P. Groner and T. G. Wright, J. Chem. Phys., (2017, in press). W. D. Tuttle, A. M. Gardner, K. O'Regan, W. Malewicz and T. G. Wright, J. Chem. Phys., (2017, in press).
Takiar, Vinita; Fontanilla, Hiral P.; Eifel, Patricia J.; Jhingran, Anuja; Kelly, Patrick; Iyer, Revathy B.; Levenback, Charles F.; Zhang, Yongbin; Dong, Lei; Klopp, Ann
2013-03-15
Purpose: Conformal treatment of para-aortic lymph nodes (PAN) in cervical cancer allows dose escalation and reduces normal tissue toxicity. Currently, data documenting the precise location of involved PAN are lacking. We define the spatial distribution of this high-risk nodal volume by analyzing fluorodeoxyglucose (FDG)-avid lymph nodes (LNs) on positron emission tomography/computed tomography (PET/CT) scans in patients with cervical cancer. Methods and Materials: We identified 72 PANs on pretreatment PET/CT of 30 patients with newly diagnosed stage IB-IVA cervical cancer treated with definitive chemoradiation. LNs were classified as left-lateral para-aortic (LPA), aortocaval (AC), or right paracaval (RPC). Distances from the LN center to the closest vessel and adjacent vertebral body were calculated. Using deformable image registration, nodes were mapped to a template computed tomogram to provide a visual impression of nodal frequencies and anatomic distribution. Results: We identified 72 PET-positive para-aortic lymph nodes (37 LPA, 32 AC, 3 RPC). All RPC lymph nodes were in the inferior third of the para-aortic region. The mean distance from aorta for all lymph nodes was 8.3 mm (range, 3-17 mm), and from the inferior vena cava was 5.6 mm (range, 2-10 mm). Of the 72 lymph nodes, 60% were in the inferior third, 36% were in the middle third, and 4% were in the upper third of the para-aortic region. In all, 29 of 30 patients also had FDG-avid pelvic lymph nodes. Conclusions: A total of 96% of PET positive nodes were adjacent to the aorta; PET positive nodes to the right of the IVC were rare and were all located distally, within 3 cm of the aortic bifurcation. Our findings suggest that circumferential margins around the vessels do not accurately define the nodal region at risk. Instead, the anatomical extent of the nodal basin should be contoured on each axial image to provide optimal coverage of the para-aortic nodal compartment.
NASA Astrophysics Data System (ADS)
Fletcher, Leigh N.; Irwin, Patrick G.; Sinclair, James; Giles, Rohini; Barstow, Joanna; Achterberg, Richard K.; Orton, Glenn S.
2014-11-01
Cassini/CIRS observations of Saturn’s 10-1400 cm-1 spectrum have been inverted to construct a global record of tropospheric temperature and para-hydrogen variability over the ten-year span of the Cassini mission. The data record the slow reversal of seasonal asymmetries in tropospheric conditions from northern winter (2004, Ls=293), through northern spring equinox (2009, Ls=0) to the present day (2014, Ls=60). Mid-latitude tropospheric temperatures have cooled by approximately 4-6 K in the south and warmed by 2-4 K in the north, with the seasonal contrast decreasing with depth. CIRS detected the north polar minimum 100-mbar temperatures 6-8 years after winter solstice, whereas the south polar maximum occurred 1-2 years after summer solstice, consistent with the lag times predicted by radiative equilibrium models. Warm polar cyclones and the northern hexagon persist throughout the mission, suggesting that they are permanent features of Saturn’s tropospheric circulation. The 200-mbar thermal enhancement (“knee”) that was strongest in the summer but weak or absent in winter in 2004-2006 (Fletcher et al., 2007, Icarus 189, p.457-478) has now shifted northward and is present globally in 2014, suggestive of radiative heating in Saturn’s tropospheric haze layer. Saturn’s para-H2 fraction, which serves as a tracer of both tropospheric mixing and the efficiency of re-equilibration between the ortho- and para-hydrogen states, is slowly altering: super-equilibrium conditions (para-H2 fraction exceeding equilibrium expectations and suggestive of subsiding airmasses) that dominated the southern summer hemisphere are now weakening, whereas the sub-equilibrium conditions (suggestive of uplift) of the northern winter are being replaced by equilibrium or super-equilibrium conditions in spring. The thermal ‘knee’ and the para-H2 distribution are tracking both the increased spring illumination and the increasing tropospheric haze opacity of the springtime hemisphere
Astronomia para/com crianças carentes em Limeira
NASA Astrophysics Data System (ADS)
Bretones, P. S.; Oliveira, V. C.
2003-08-01
Em 2001, o Instituto Superior de Ciências Aplicadas (ISCA Faculdades de Limeira) iniciou um projeto pelo qual o Observatório do Morro Azul empreendeu uma parceria com o Centro de Promoção Social Municipal (CEPROSOM), instituição mantida pela Prefeitura Municipal de Limeira para atender crianças e adolescentes carentes. O CEPROSOM contava com dois projetos: Projeto Centro de Convivência Infantil (CCI) e Programa Criança e Adolescente (PCA), que atendiam crianças e adolescentes em Centros Comunitários de diversas áreas da cidade. Esses projetos têm como prioridades estabelecer atividades prazerosas para as crianças no sentido de retirá-las das ruas. Assim sendo, as crianças passaram a ter mais um tipo de atividade - as visitas ao observatório. Este painel descreve as várias fases do projeto, que envolveu: reuniões de planejamento, curso de Astronomia para as orientadoras dos CCIs e PCAs, atividades relacionadas a visitas das crianças ao Observatório, proposta de construção de gnômons e relógios de Sol nos diversos Centros Comunitários de Limeira e divulgação do projeto na imprensa. O painel inclui discussões sobre a aprendizagem de crianças carentes, relatos que mostram a postura das orientadoras sobre a pertinência do ensino de Astronomia, relatos do monitor que fez o atendimento no Observatório e o que o número de crianças atendidas representou para as atividades da instituição desde o início de suas atividades e, em particular, em 2001. Os resultados são baseados na análise de relatos das orientadoras e do monitor do Observatório, registros de visitas e matérias da imprensa local. Conclui com uma avaliação do que tal projeto representou para as Instituições participantes. Para o Observatório, em particular, foi feita uma análise com relação às outras modalidades de atendimentos que envolvem alunos de escolas e público em geral. Também é abordada a questão do compromisso social do Observatório na educação do