bluuebunny/crossref_metadata_2025_split huggingface dataset:
CALIBRATION OF EVOLUTIONARY DIAGNOSTICS IN HIGH-MASS STAR FORMATION
Authors: Molinari S. , Merello M. , Elia D. , Cesaroni R. , Testi L. , Robitaille T. 
Published: July 2016

ABSTRACT
The evolutionary classification of massive clumps that are candidate progenitors of high-mass young stars and clusters relies on a variety of independent diagnostics based on observables from the near-infrared to the radio. A promising evolutionary indicator for massive and dense cluster-progenitor clumps is the L/M ratio between the bolometric luminosity and the mass of the clumps. With the aim of providing a quantitative calibration for this indicator, we used SEPIA/APEX to obtain CH3C2H(J = 12–11) observations, which is an excellent thermometer molecule probing densities

≥

10

5

cm−3, toward 51 dense clumps with

M
≥
1000

M

⊙

and uniformly spanning −2 ≲ Log(L/M) [L

⊙

/M

⊙

] ≲ 2.3. We identify three distinct ranges of L/M that can be associated to three distinct phases of star formation in massive clumps. For L/M

≤

1

no clump is detected in CH3C2H, suggesting an inner envelope temperature below ∼30K. For 1 ≲ L/M ≲ 10 we detect 58% of the clumps with a temperature between ∼30 and ∼35 K independently from the exact value of L/M; such clumps are building up luminosity due to the formation of stars, but no star is yet able to significantly heat the inner clump regions. For L/M ≳ 10 we detect all the clumps with a gas temperature rising with Log(L/M), marking the appearance of a qualitatively different heating source within the clumps; such values are found toward clumps with UCH ii counterparts, suggesting that the quantitative difference in T versus L/M behavior above L/M ∼ 10 is due to the first appearance of ZAMS stars in the clumps.
ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES?
Authors: Zaritsky Dennis , Crnojević Denija , Sand David J. 
Published: July 2016

ABSTRACT
The confirmation of a globular cluster (GC) in the recently discovered ultrafaint galaxy Eridanus II (Eri II) motivated us to examine the question posed in the title. After estimating the halo mass of Eri II using a published stellar mass—halo mass relation, the one GC in this galaxy supports extending the relationship between the number of GCs hosted by a galaxy and the galaxy’s total mass about two orders of magnitude in stellar mass below the previous limit. For this empirically determined specific frequency of between 0.06 and 0.39 GCs per 109
M
⊙ of total mass, the surviving Milky Way (MW) subhalos with masses smaller than 1010
M
⊙ could host as many as 5–31 GCs, broadly consistent with the actual population of outer halo MW GCs, although matching the radial distribution in detail remains a challenge. Using a subhalo mass function from published high-resolution numerical simulations and a Poissonian model for populating those halos with the aforementioned empirically constrained frequency, we find that about 90% of these GCs lie in lower-mass subhalos than that of Eri II. From what we know about the stellar mass–halo mass function, the subhalo mass function, and the mass-normalized GC specific frequency, we conclude that some of the MW’s outer halo GCs are likely to be hosted by undetected subhalos with extremely modest stellar populations.
Les caractéristiques des managers comme prédicteurs de faillite des PME belges ?
Authors: Cultrera Loredana 
Published: July 2016

Cet article fournit les premières mises en évidence de caractéristiques spécifiques aux managers pouvant expliquer le déclenchement du processus de défaillance d’entreprise. Il cherche à mettre en évidence les facteurs susceptibles d’entraîner la faillite des PME belges, au moyen d’entretiens individuels effectués auprès de spécialistes du domaine. Les différents entretiens semi-directifs menés, analysés au moyen de la technique de théorisation ancrée, suggèrent que le niveau d’éducation et de formation du dirigeant, ainsi que sa capacité à réagir à un environnement changeant et son orientation vers des processus de contrôle opérationnel et administratif permanents sont les facteurs principaux favorisant la survie de l’entreprise. Classification JEL : G32, G33, H12
The relationship of postural body stability and severity of malocclusion
Authors: Arumugam Prasanna , Padmanabhan Sridevi , Chitharanjan Arun B. 
Published: July 2016

Objective
To evaluate the relationship between postural body stability (static and dynamic) and malocclusions of varying severity and to find whether different skeletal patterns showed variation in postural body stability.

Materials and Methods
Seventy-five subjects were divided into three groups based on case complexity using ABO discrepancy index. Group A consisted of 25 subjects restricted to Class I skeletal base and an ABO score ≤10; Group B consisted of 25 subjects with either Class II or III skeletal base and an ABO score of 11–25; Group C consisted of 25 subjects with either Class II or III skeletal base and an ABO score >25. Postural body stability in both static and dynamic equilibrium was recorded using a computerized dynamic posturography. The average values were obtained for the scores obtained in each group and the data obtained wes subjected to statistical analysis using one-way analysis of variance and post hoc Tukey’s test. A P ≤ 0.05 was considered significant.

Results
In both static and dynamic conditions, postural body stability was inversely proportional to the severity of malocclusion. The assessment of the overall body score showed that subjects in Group A and Group B had acceptable postural stability and only subjects with Group C showed statistically significant lack of postural stability.

Conclusions
Our study showed that patients with malocclusion showed decreased stability and increased sway with increasing severity of malocclusion.
A Flexible Boundary Procedure for Hyperbolic Problems: Multiple Penalty Terms Applied in a Domain
Authors: Nordström Jan , Abbas Qaisar , Erickson Brittany A. , Frenander Hannes 
Published: July 2016

AbstractA new weak boundary procedure for hyperbolic problems is presented. We consider high order finite difference operators of summation-by-parts form with weak boundary conditions and generalize that technique. The new boundary procedure is applied near boundaries in an extended domain where data is known. We show how to raise the order of accuracy of the scheme, how to modify the spectrum of the resulting operator and how to construct non-reflecting properties at the boundaries. The new boundary procedure is cheap, easy to implement and suitable for all numerical methods, not only finite difference methods, that employ weak boundary conditions. Numerical results that corroborate the analysis are presented.
Simulation of Inviscid Compressible Flows Using PDE Transform
Authors: Hu Langhua , Yang Siyang , Wei Guo-Wei 
Published: July 2016

AbstractThe solution of systems of hyperbolic conservation laws remains an interesting and challenging task due to the diversity of physical origins and complexity of the physical situations. The present work introduces the use of the partial differential equation (PDE) transform, paired with the Fourier pseudospectral method (FPM), as a new approach for hyperbolic conservation law problems. The PDE transform, based on the scheme of adaptive high order evolution PDEs, has recently been applied to decompose signals, images, surfaces and data to various target functional mode functions such as trend, edge, texture, feature, trait, noise, etc. Like wavelet transform, the PDE transform has controllable time-frequency localization and perfect reconstruction. A fast PDE transform implemented by the fast Fourier Transform (FFT) is introduced to avoid stability constraint of integrating high order PDEs. The parameters of the PDE transform are adaptively computed to optimize the weighted total variation during the time integration of conservation law equations. A variety of standard benchmark problems of hyperbolic conservation laws is employed to systematically validate the performance of the present PDE transform based FPM. The impact of two PDE transform parameters, i.e., the highest order and the propagation time, is carefully studied to deliver the best effect of suppressing Gibbs’ oscillations. The PDE orders of 2-6 are used for hyperbolic conservation laws of low oscillatory solutions, while the PDE orders of 8-12 are often required for problems involving highly oscillatory solutions, such as shock-entropy wave interactions. The present results are compared with those in the literature. It is found that the present approach not only works well for problems that favor low order shock capturing schemes, but also exhibits superb behavior for problems that require the use of high order shock capturing methods.
Numerical Analysis of an Adaptive FEM for Distributed Flux Reconstruction
Authors: Li Mingxia , Li Jingzhi , Mao Shipeng 
Published: July 2016

AbstractThis paper studies convergence analysis of an adaptive finite element algorithm for numerical estimation of some unknown distributed flux in a stationary heat conduction system, namely recovering the unknown Neumann data on interior inaccessible boundary using Dirichlet measurement data on outer accessible boundary. Besides global upper and lower bounds established in [23], a posteriori local upper bounds and quasi-orthogonality results concerning the discretization errors of the state and adjoint variables are derived. Convergence and quasi-optimality of the proposed adaptive algorithm are rigorously proved. Numerical results are presented to illustrate the quasi-optimality of the proposed adaptive method.
Quantum Dynamics in Continuum for Proton Transport I: Basic Formulation
Authors: Chen Duan , Wei Guo-Wei 
Published: July 2016

AbstractProton transport is one of the most important and interesting phenomena in living cells. The present work proposes a multiscale/multiphysics model for the understanding of the molecular mechanism of proton transport in transmembrane proteins. We describe proton dynamics quantum mechanically via a density functional approach while implicitly model other solvent ions as a dielectric continuum to reduce the number of degrees of freedom. The densities of all other ions in the solvent are assumed to obey the Boltzmann distribution. The impact of protein molecular structure and its charge polarization on the proton transport is considered explicitly at the atomic level. We formulate a total free energy functional to put proton kinetic and potential energies as well as electrostatic energy of all ions on an equal footing. The variational principle is employed to derive nonlinear governing equations for the proton transport system. Generalized Poisson-Boltzmann equation and Kohn-Sham equation are obtained from the variational framework. Theoretical formulations for the proton density and proton conductance are constructed based on fundamental principles. The molecular surface of the channel protein is utilized to split the discrete protein domain and the continuum solvent domain, and facilitate the multiscale discrete/continuum/quantum descriptions. A number of mathematical algorithms, including the Dirichlet to Neumann mapping, matched interface and boundary method, Gummel iteration, and Krylov space techniques are utilized to implement the proposed model in a computationally efficient manner. The Gramicidin A (GA) channel is used to demonstrate the performance of the proposed proton transport model and validate the efficiency of proposed mathematical algorithms. The electrostatic characteristics of the GA channel is analyzed with a wide range of model parameters. The proton conductances are studied over a number of applied voltages and reference concentrations. A comparison with experimental data verifies the present model predictions and validates the proposed model.
Implicit-Explicit Runge-Kutta Schemes for the Boltzmann-Poisson System for Semiconductors
Authors: Dimarco Giacomo , Pareschi Lorenzo , Rispoli Vittorio 
Published: July 2016

AbstractIn this paper we develop a class of Implicit-Explicit Runge-Kutta schemes for solving the multi-scale semiconductor Boltzmann equation. The relevant scale which characterizes this kind of problems is the diffusive scaling. This means that, in the limit of zero mean free path, the system is governed by a drift-diffusion equation. Our aim is to develop a method which accurately works for the different regimes encountered in general semiconductor simulations: the kinetic, the intermediate and the diffusive one. Moreover, we want to overcome the restrictive time step conditions of standard time integration techniques when applied to the solution of this kind of phenomena without any deterioration in the accuracy. As a result, we obtain high order time and space discretization schemes which do not suffer from the usual parabolic stiffness in the diffusive limit. We show different numerical results which permit to appreciate the performances of the proposed schemes.
Dirichlet-to-Neumann Mapping for the Characteristic Elliptic Equations with Symmetric Periodic Coefficients
Authors: Kang Jingsu , Zhang Meirong , Zheng Chunxiong 
Published: July 2016

AbstractBased on the numerical evidences, an analytical expression of the Dirichlet-to-Neumann mapping in the form of infinite product was first conjectured for the one-dimensional characteristic Schrödinger equation with a sinusoidal potential in [Commun. Comput. Phys., 3(3): 641-658, 2008]. It was later extended for the general second-order characteristic elliptic equations with symmetric periodic coefficients in [J. Comp. Phys., 227: 6877-6894, 2008]. In this paper, we present a proof for this Dirichlet-to-Neumann mapping.
Local Discontinuous Galerkin Methods for the 2D Simulation of Quantum Transport Phenomena on Quantum Directional Coupler
Authors: Guo Li , Xu Yan 
Published: July 2016

AbstractIn this paper, we present local discontinuous Galerkin methods (LDG) to simulate an important application of the 2D stationary Schrödinger equation called quantum transport phenomena on a typical quantum directional coupler, which frequency change mainly reflects in y-direction. We present the minimal dissipation LDG (MD-LDG) method with polynomial basis functions for the 2D stationary Schrödinger equation which can describe quantum transport phenomena. We also give the MD-LDG method with polynomial basis functions in x-direction and exponential basis functions in y-direction for the 2D stationary Schrödinger equation to reduce the computational cost. The numerical results are shown to demonstrate the accuracy and capability of these methods.
Fourth Order Difference Approximations for Space Riemann-Liouville Derivatives Based on Weighted and Shifted Lubich Difference Operators
Authors: Chen Minghua , Deng Weihua 
Published: July 2016

AbstractHigh order discretization schemes play more important role in fractional operators than classical ones. This is because usually for classical derivatives the stencil for high order discretization schemes is wider than low order ones; but for fractional operators the stencils for high order schemes and low order ones are the same. Then using high order schemes to solve fractional equations leads to almost the same computational cost with first order schemes but the accuracy is greatly improved. Using the fractional linear multistep methods, Lubich obtains thev-th order (v <6) approximations of theα-th derivative (α >0) or integral (α <0) [Lubich, SIAM J. Math. Anal., 17, 704-719, 1986], because of the stability issue the obtained scheme can not be directly applied to the space fractional operator withαЄ (1,2) for time dependent problem. By weighting and shifting Lubich’s 2nd order discretization scheme, in [Chen & Deng, SINUM, arXiv:1304.7425] we derive a series of effective high order discretizations for space fractional derivative, called WSLD operators there. As the sequel of the previous work, we further provide new high order schemes for space fractional derivatives by weighting and shifting Lubich’s 3rd and 4th order discretizations. In particular, we prove that the obtained 4th order approximations are effective for space fractional derivatives. And the corresponding schemes are used to solve the space fractional diffusion equation with variable coefficients.
The Modern Information Technologies and Visualization Methods for Analysis of Computer Simulation Results for Complex Plasma
Authors: Ramazanov T. S. , Kodanova S. K. , Issanova M. K. , Bastykova N. Kh. , Moldabekov Zh. A. 
Published: July 2016

AbstractIn this paper we present a software package based on modern information technologies that allows rapid analysis and visualization of the properties of complex plasmas. The properties of plasma are simulated by two means. First of all, we have applied the molecular dynamics simulation method which numerically solves the equations of motions for plasma particles. Secondly, we calculate microscopic properties of plasma by using the Boltzmann equation with additional relations, initial and boundary conditions.
A Conservative Local Discontinuous Galerkin Method for the Schrödinger-KdV System
Authors: Xia Yinhua , Xu Yan 
Published: July 2016

AbstractIn this paper we develop a conservative local discontinuous Galerkin (LDG) method for the Schrödinger-Korteweg-de Vries (Sch-KdV) system, which arises in various physical contexts as a model for the interaction of long and short nonlinear waves. Conservative quantities in the discrete version of the number of plasmons, energy of the oscillations and the number of particles are proved for the LDG scheme of the Sch-KdV system. Semi-implicit time discretization is adopted to relax the time step constraint from the high order spatial derivatives. Numerical results for accuracy tests of stationary traveling soliton, and the collision of solitons are shown. Numerical experiments illustrate the accuracy and capability of the method.
A Nonlinear PIC Algorithm for High Frequency Waves in Magnetized Plasmas Based on Gyrocenter Gauge Kinetic Theory
Authors: Liu Jian , Yu Zhi , Qin Hong 
Published: July 2016

AbstractNumerical methods based on gyrocenter gauge kinetic theory are suitable for first principle simulations of high frequency waves in magnetized plasmas. The δf gyrocenter gauge PIC simulation for linear rf wave has been previously realized. In this paper we further develop a full-f nonlinear PIC algorithm appropriate for the nonlinear physics of high frequency waves in magnetized plasmas. Numerical cases of linear rf waves are calculated as a benchmark for the nonlinear GyroGauge code, meanwhile nonlinear rf-wave phenomena are studied. The technique and advantage of the reduction of the numerical noise in this full-f gyrocenter gauge PIC algorithm are also discussed.
A Scalable Numerical Method for Simulating Flows Around High-Speed Train Under Crosswind Conditions
Authors: Yan Zhengzheng , Chen Rongliang , Zhao Yubo , Cai Xiao-Chuan 
Published: July 2016

AbstractThis paper presents a parallel Newton-Krylov-Schwarz method for the numerical simulation of unsteady flows at high Reynolds number around a high-speed train under crosswind. With a realistic train geometry, a realistic Reynolds number, and a realistic wind speed, this is a very challenging computational problem. Because of the limited parallel scalability, commercial CFD software is not suitable for supercomputers with a large number of processors. We develop a Newton-Krylov-Schwarz based fully implicit method, and the corresponding parallel software, for the 3D unsteady incompressible Navier-Stokes equations discretized with a stabilized finite element method on very fine unstructured meshes. We test the algorithm and software for flows passing a train modeled after China’s high-speed train CRH380B, and we also compare our results with results obtained from commercial CFD software. Our algorithm shows very good parallel scalability on a supercomputer with over one thousand processors.
DelEnsembleElec: Computing Ensemble-Averaged Electrostatics Using DelPhi
Authors: Votapka Lane W. , Czapla Luke , Zhenirovskyy Maxim , Amaro Rommie E. 
Published: July 2016

AbstractA new VMD plugin that interfaces with DelPhi to provide ensemble-averaged electrostatic calculations using the Poisson-Boltzmann equation is presented. The general theory and context of this approach are discussed, and examples of the plugin interface and calculations are presented. This new tool is applied to systems of current biological interest, obtaining the ensemble-averaged electrostatic properties of the two major influenza virus glycoproteins, hemagglutinin and neuraminidase, from explicitly solvated all-atom molecular dynamics trajectories. The differences between the ensemble-averaged electrostatics and those obtained from a single structure are examined in detail for these examples, revealing how the plugin can be a powerful tool in facilitating the modeling of electrostatic interactions in biological systems.
Solving Two-Mode Shallow Water Equations Using Finite Volume Methods
Authors: Castro Diaz Manuel Jesús , Cheng Yuanzhen , Chertock Alina , Kurganov Alexander 
Published: July 2016

AbstractIn this paper, we develop and study numerical methods for the two-mode shallow water equations recently proposed in [S. STECHMANN, A. MAJDA, and B. KHOUIDER, Theor. Comput. Fluid Dynamics, 22 (2008), pp. 407-432]. Designing a reliable numerical method for this system is a challenging task due to its conditional hyperbolicity and the presence of nonconservative terms. We present several numerical approaches—two operator splitting methods (based on either Roe-type upwind or central-upwind scheme), a central-upwind scheme and a path-conservative central-upwind scheme—and test their performance in a number of numerical experiments. The obtained results demonstrate that a careful numerical treatment of nonconservative terms is crucial for designing a robust and highly accurate numerical method.
The Lognormal Distribution and Quantum Monte Carlo Data
Authors: Moodley Mervlyn 
Published: July 2016

AbstractQuantum Monte Carlo data are often afflicted with distributions that resemble lognormal probability distributions and consequently their statistical analysis cannot be based on simple Gaussian assumptions. To this extent a method is introduced to estimate these distributions and thus give better estimates to errors associated with them. This method entails reconstructing the probability distribution of a set of data, with given mean and variance, that has been assumed to be lognormal prior to undergoing a blocking or renormalization transformation. In doing so, we perform a numerical evaluation of the renormalized sum of lognormal random variables. This technique is applied to a simple quantum model utilizing the single-thread Monte Carlo algorithm to estimate the ground state energy or dominant eigenvalue of a Hamiltonian matrix.