bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limited Sampling Strategies to Estimate the Area under the Concentration-time Curve
Authors: Fukumoto M. , Bax L. , Kohno A. , Morishita Y. , Tsuruta H. 
Published: May 2012

SummaryBackground: Over 100 limited sampling strategies (LSSs) have been proposed to reduce the number of blood samples necessary to estimate the area under the concentration-time curve (AUC). The conditions under which these strategies succeed or fail remain to be clarified.Objectives: We investigated the accuracy of existing LSSs both theoretically and numerically by Monte Carlo simulation. We also proposed two new methods for more accurate AUC estimations.Methods: We evaluated the following existing methods theoretically: i) nonlinear curve fitting algorithm (NLF), ii) the trapezium rule with exponential curve approximation (TZE), and iii) multiple linear regression (MLR). Taking busulfan (BU) as a test drug, we generated a set of theoretical concentration-time curves based on the identified distribution of pharmacokinetic parameters of BU and re-evaluated the existing LSSs using these virtual validation profiles. Based on the evaluation results, we improved the TZE so that unrealistic parameter values were not used. We also proposed a new estimation method in which the most likely curve was selected from a set of pre-generated theoretical concentration-time curves.Results: Our evaluation, based on clinical profiles and a virtual validation set, revealed: i) NLF sometimes overestimated the absorption rate constant Ka, ii) TZE overestimated AUC over 280% when Ka is small, and iii) MLR underestimated AUC over 30% when the elimination rate constant Ke is small. These results were consistent with our mathematical evaluations for these methods. In contrast, our two new methods had little bias and good precision.Conclusions: Our investigation revealed that existing LSSs induce different but specific biases in the estimation of AUC. Our two new LSSs, a modified TZE and one using model concentration-time curves, provided accurate and precise estimations of AUC.
Microsatellite markers for Bistorta vivipara (Polygonaceae)
Authors: Vik Unni , Carlsen Tor , Eidesen Pernille Bronken , Brysting Anne Krag , Kauserud Håvard 
Published: May 2012

• Premise of the study: Using genomic shotgun 454 sequencing, 50 candidate microsatellite markers were targeted for the arctic–alpine polyploid perennial herb Bistorta vivipara to distinguish between individual genets and ramets within a population.• Methods and Results: Out of the 50 markers, 31 were polymorphic for seven test samples. We have developed a multiplex protocol for 16 of these microsatellite markers.• Conclusions: Our results show that the microsatellite markers provide a powerful tool for the research on genetic variation of B. vivipara.
Isolation and characterization of microsatellite markers from Clematoclethra scandens (Actinidiaceae)
Authors: Li Lu , Chen Li , Zhang Zhi‐Rong , Xiao Long‐Qian 
Published: May 2012

• Premise of the study: Microsatellite makers were developed for Clematoclethra scandens to investigate its population genetics and speciation.• Methods and Results: A total of 36 microsatellite markers were isolated using the Fast Isolation by AFLP of Sequences COntaining repeats (FIASCO) method. Their polymorphisms were assessed in two natural populations. The results showed that 30 markers displayed prominent polymorphisms and six markers were monomorphic.• Conclusions: These microsatellite loci will facilitate further studies on population genetics and speciation of C. scandens.
A Numerical Study of Quantum Decoherence
Authors: Adami Riccardo , Negulescu Claudia 
Published: May 2012

AbstractThe present paper provides a numerical investigation of the decoherence effect induced on a quantum heavy particle by the scattering with a light one. The time dependent two-particle Schrödinger equation is solved by means of a time-splitting method. The damping undergone by the non-diagonal terms of the heavy particle density matrix is estimated numerically as well as the error in the Joos-Zeh approximation formula.
Numerical Simulation of Glottal Flow in Interaction with Self Oscillating Vocal Folds: Comparison of Finite Element Approximation with a Simplified Model
Authors: Sváček P. , Horáček J. 
Published: May 2012

AbstractIn this paper the numerical method for solution of an aeroelastic model describing the interactions of air flow with vocal folds is described. The flow is modelled by the incompressible Navier-Stokes equations spatially discretized with the aid of the stabilized finite element method. The motion of the computational domain is treated with the aid of the Arbitrary Lagrangian Eulerian method. The structure dynamics is replaced by a mechanically equivalent system with the two degrees of freedom governed by a system of ordinary differential equations and discretized in time with the aid of an implicit multistep method and strongly coupled with the flow model. The influence of inlet/outlet boundary conditions is studied and the numerical analysis is performed and compared to the related results from literature.
Viscoelastic Immersed Boundary Methods for Zero Reynolds Number Flow
Authors: Strychalski Wanda , Guy Robert D. 
Published: May 2012

AbstractThe immersed boundary method has been extensively used to simulate the motion of elastic structures immersed in a viscous fluid. For some applications, such as modeling biological materials, capturing internal boundary viscosity is important. We present numerical methods for simulating Kelvin-Voigt and standard linear viscoelastic structures immersed in zero Reynolds number flow. We find that the explicit time immersed boundary update is unconditionally unstable above a critical boundary to fluid viscosity ratio for a Kelvin-Voigt material. We also show there is a severe time step restriction when simulating a standard linear boundary with a small relaxation time scale using the same explicit update. A stable implicit method is presented to overcome these computation challenges.
A Variational Model for Two-Phase Immiscible Electroosmotic Flow at Solid Surfaces
Authors: Shao Sihong , Qian Tiezheng 
Published: May 2012

AbstractWe develop a continuum hydrodynamic model for two-phase immiscible flows that involve electroosmotic effect in an electrolyte and moving contact line at solid surfaces. The model is derived through a variational approach based on the On-sager principle of minimum energy dissipation. This approach was first presented in the derivation of a continuum hydrodynamic model for moving contact line in neutral two-phase immiscible flows (Qian, Wang, and Sheng, J. Fluid Mech. 564, 333-360 (2006)). Physically, the electroosmotic effect can be formulated by the Onsager principle as well in the linear response regime. Therefore, the same variational approach is applied here to the derivation of the continuum hydrodynamic model for charged two-phase immiscible flows where one fluid component is an electrolyte exhibiting electroosmotic effect on a charged surface. A phase field is employed to model the diffuse interface between two immiscible fluid components, one being the electrolyte and the other a nonconductive fluid, both allowed to slip at solid surfaces. Our model consists of the incompressible Navier-Stokes equation for momentum transport, the Nernst-Planck equation for ion transport, the Cahn-Hilliard phase-field equation for interface motion, and the Poisson equation for electric potential, along with all the necessary boundary conditions. In particular, all the dynamic boundary conditions at solid surfaces, including the generalized Navier boundary condition for slip, are derived together with the equations of motion in the bulk region. Numerical examples in two-dimensional space, which involve overlapped electric double layer fields, have been presented to demonstrate the validity and applicability of the model, and a few salient features of the two-phase immiscible electroosmotic flows at solid surface. The wall slip in the vicinity ofmoving contact line and the Smoluchowski slip in the electric double layer are both investigated.
Statistics of Particle Suspensions in Turbulent Channel Flow
Authors: Zhao Lihao , Andersson Helge I. 
Published: May 2012

AbstractParticle dynamics in a turbulent channel flow is considered. The effects of particle concentration and Reynolds number on the particle velocity statistics are investigated. Four different particle response times, τ+=1, 5, 30 and 100, are examined for three different Reynolds numbers, Re*=200, 360 and 790 (based on channel height and friction velocity). The particle concentration evolves with time and statistics obtained during three different sampling periods might be distinctly different. The mean and fluctuating particle velocities are substantially affected both by the particle response time and by the Reynolds number of the flow.
An Iterative Two-Fluid Pressure Solver Based on the Immersed Interface Method
Authors: Xu Sheng 
Published: May 2012

AbstractAn iterative solver based on the immersed interface method is proposed to solve the pressure in a two-fluid flow on a Cartesian grid with second-order accuracy in the infinity norm. The iteration is constructed by introducing an unsteady term in the pressure Poisson equation. In each iteration step, a Helmholtz equation is solved on the Cartesian grid using FFT. The combination of the iteration and the immersed interface method enables the solver to handle various jump conditions across two-fluid interfaces. This solver can also be used to solve Poisson equations on irregular domains.
High-Order Low Dissipation Conforming Finite-Element Discretization of the Maxwell Equations
Authors: Jund Sébastien , Salmon Stéphanie , Sonnendrücker Eric 
Published: May 2012

AbstractIn this paper, we study high order discretization methods for solving the Maxwell equations on hybrid triangle-quad meshes. We have developed high order finite edge element methods coupled with different high order time schemes and we compare results and efficiency for several schemes. We introduce in particular a class of simple high order low dissipation time schemes based on a modified Taylor expansion.
Composite Coherent States Approximation for One-Dimensional Multi-Phased Wave Functions
Authors: Yin Dongsheng , Zheng Chunxiong 
Published: May 2012

AbstractThe coherent states approximation for one-dimensional multi-phased wave functions is considered in this paper. The wave functions are assumed to oscillate on a characteristic wave length 0(ε) with ε ≪ 1. A parameter recovery algorithm is first developed for single-phased wave function based on a moment asymptotic analysis. This algorithm is then extended to multi-phased wave functions. If cross points or caustics exist, the coherent states approximation algorithm based on the parameter recovery will fail in some local regions. In this case, we resort to the windowed Fourier transform technique, and propose a composite coherent states approximation method. Numerical experiments show that the number of coherent states derived by the proposed method is much less than that by the direct windowed Fourier transform technique.
Computational Methods for Electromechanical Fields in Self-Assembled Quantum Dots
Authors: Barettin D. , Madsen S. , Lassen B. , Willatzen M. 
Published: May 2012

AbstractA detailed comparison of continuum and valence force field strain calculations in quantum-dot structures is presented with particular emphasis to boundary conditions, their implementation in the finite-element method, and associated implications for electronic states. The first part of this work provides the equation framework for the elastic continuum model including piezoelectric effects in crystal structures as well as detailing the Keating model equations used in the atomistic valence force field calculations. Given the variety of possible structure shapes, a choice of pyramidal, spherical and cubic-dot shapes is made having in mind their pronounced shape differences and practical relevance. In this part boundary conditions are also considered; in particular the relevance of imposing different types of boundary conditions is highlighted and discussed.
Computational Investigation of the Interaction Between Hydrogen Atoms and an Intense Circularly Polarized Laser Field
Authors: Yang Lifeng , Xu Wang , Zhang Qiren , Luo Wen , Pan Qiangyan , Cai Xiaolu , Fan Gongtao , Li Yongjiang , Xu Benji , Yan Zhe , Fan Guangwei , An Zhendong 
Published: May 2012

AbstractThe study of interactions between a high-power laser and atoms has been one of the fundamental and interesting topics in strong field physics for decades. Based on a nonperturbative model, ten years ago, we developed a set of programs to facilitate the study of interactions between a circularly polarized laser and atomic hydrogen. These programs included only contribution from the bound states of the hydrogen atom. However, as the laser intensity increases, contribution from continuum states to the excitation and ionization processes becomes larger and can no longer be neglected. Furthermore, because the original code is not able to add this contribution directly due to its many disadvantages, a major upgrade of the code is required before including the contribution from continuum states in future. In this paper, first we deduce some important formulas for contribution of continuum states and present modifications and tests for the upgraded code in detail. Second we show some comparisons among new results, old results from the original codes and the available experimental data. Overall the new result agrees with experimental data well. Last we present our calculation of above-threshold ionization (ATI) rate and compare it with a pertuba-tive calculation. The comparison shows that our nonperturbative calculation can also produce ATI peak suppression.
Oblique Drop Impact on Deep and Shallow Liquid
Authors: Ray B. , Biswas G. , Sharma A. 
Published: May 2012

AbstractNumerical simulations using CLSVOF (coupled level set and volume of fluid) method are performed to investigate the coalescence and splashing regimes when a spherical water drop hits on the water surface with an impingement angle. Impingement angle is the angle between the velocity vector of primary drop and the normal vector to water surface. The effect of impingement angle, impact velocity and the height of target liquid are carried out. The impingement angle is varied from 0° to 90° showing the gradual change in phenomena. The formation of ship pro like shape, liquid sheet, secondary drops and crater are seen. Crater height, crater displacement, crown height and crown angle are calculated and the change in the parameters with change in impingement angle is noted.
Simulation of Plasma Flow Injection with Multi-Hierarchy Model Aiming Magnetic Reconnection Studies
Authors: Usami S. , Ohtani H. , Horiuchi R. , Den M. 
Published: May 2012

AbstractA multi-hierarchy simulation model aiming magnetic reconnection studies is developed and improved in which macroscopic and microscopic physics are computed consistently and simultaneously. Macroscopic physics is solved by mag-netohydrodynamics (MHD) algorithm, while microscopic dynamics is expressed by particle-in-cell (PIC) algorithm. The multi-hierarchy model relies on the domain decomposition method, and macro- and micro-hierarchies are interlocked smoothly by hand-shake scheme. As examination, plasma flow injection is simulated in the multi-hierarchy model. It is observed that plasmas flow from a macro-hierarchy to a micro-hierarchy across the magnetic field smoothly and continuously.
A New Variational Model with Dual Level Set Functions for Selective Segmentation
Authors: Rada Lavdie , Chen Ke 
Published: May 2012

AbstractIn this paper we present a selective segmentation model using a dual level set variational formulation. Our variational model aims to segment all objects with one level set function (global) and the selected object, which is the closest to the geometric constraints (markers), with another level set (local). It is a combination of edge detection, markers distance function and active contour without edges. Experimental results show that our model is more robust than previous work.
An Immersed Interface Method for the Simulation of Inextensible Interfaces in Viscous Fluids
Authors: Tan Zhijun , Le D. V. , Lim K. M. , Khoo B. C. 
Published: May 2012

AbstractIn this paper, an immersed interface method is presented to simulate the dynamics of inextensible interfaces in an incompressible flow. The tension is introduced as an augmented variable to satisfy the constraint of interface inextensibility and the resulting augmented system is solved by the GMRES method. In this work, the arclength of the interface is locally and globally conserved as the enclosed region undergoes deformation. The forces at the interface are calculated from the configuration of the interface and the computed augmented variable, and then applied to the fluid through the related jump conditions. The governing equations are discretized on a MAC grid via a second-order finite difference scheme which incorporates jump contributions and solved by the conjugate gradient Uzawa-type method. The proposed method is applied to several examples including the deformation of a liquid capsule with inextensible interfaces in a shear flow. Numerical results reveal that both the area enclosed by interface and arclength of interface are conserved well simultaneously. These provide further evidence on the capability of the present method to simulate incompressible flows involving inextensible interfaces.
Improving the High Order Spectral Volume Formulation Using a Diffusion Regulator
Authors: Kannan Ravi , Wang Zhijian 
Published: May 2012

AbstractThe concept of diffusion regulation (DR) was originally proposed by Jaisankar for traditional second order finite volume Euler solvers. This was used to decrease the inherent dissipation associated with using approximate Riemann solvers. In this paper, the above concept is extended to the high order spectral volume (SV) method. The DR formulation was used in conjunction with the Rusanov flux to handle the inviscid flux terms. Numerical experiments were conducted to compare and contrast the original and the DR formulations. These experiments demonstrated (i) retention of high order accuracy for the new formulation, (ii) higher fidelity of the DR formulation, when compared to the original scheme for all orders and (iii) straightforward extension to Navier Stokes equations, since the DR does not interfere with the discretization of the viscous fluxes. In general, the 2D numerical results are very promising and indicate that the approach has a great potential for 3D flow problems.
Numerical Methods for Fluid-Structure Interaction — A Review
Authors: Hou Gene , Wang Jin , Layton Anita 
Published: May 2012

AbstractThe interactions between incompressible fluid flows and immersed structures are nonlinear multi-physics phenomena that have applications to a wide range of scientific and engineering disciplines. In this article, we review representative numerical methods based on conforming and non-conforming meshes that are currently available for computing fluid-structure interaction problems, with an emphasis on some of the recent developments in the field. A goal is to categorize the selected methods and assess their accuracy and efficiency. We discuss challenges faced by researchers in this field, and we emphasize the importance of interdisciplinary effort for advancing the study in fluid-structure interactions.
Phase-Field Models for Multi-Component Fluid Flows
Authors: Kim Junseok 
Published: May 2012

AbstractIn this paper, we review the recent development of phase-field models and their numerical methods for multi-component fluid flows with interfacial phenomena. The models consist of a Navier-Stokes system coupled with a multi-component Cahn-Hilliard system through a phase-field dependent surface tension force, variable density and viscosity, and the advection term. The classical infinitely thin boundary of separation between two immiscible fluids is replaced by a transition region of a small but finite width, across which the composition of the mixture changes continuously. A constant level set of the phase-field is used to capture the interface between two immiscible fluids. Phase-field methods are capable of computing topological changes such as splitting and merging, and thus have been applied successfully to multi-component fluid flows involving large interface deformations. Practical applications are provided to illustrate the usefulness of using a phase-field method. Computational results of various experiments show the accuracy and effectiveness of phase-field models.
Welfare during gathering and loading of deer bred for meat in Italy
Authors: Quiliquini D , Alpigiani I 
Published: May 2012

AbstractThe aim of this study was to evaluate welfare status and the implementation of Regulation (EC) 1/2005 during the gathering and loading of deer(Cervus elaphus)bred for meat in Northern Italy. Four journeys overland along with related operations of 45 deer, destined for game farms, were observed over a period of four months. Planning, animal-management procedures, equipment and facilities, such as enclosures and corridors, influenced the success of the operations and affected the safety of animals and operators. Environmental factors, such as land inclination, were also extremely influential. Elements of the gathering technique led to stress and hyperventilation in a number of animals that were rounded up. Chemical restraint of deer was complicated by consequent physical manipulation and an inability to control withdrawal periods in game reserves. Where facilities were specific to deer, animals displayed no signs of distress and loading was carried out in the absence of stressful behaviour. Instances in which means of transport were nonspecific for deer were characterised by falls, escape and trauma during loading and unloading. Where operators had been trained and had extensive knowledge of deer physiology and behaviour, welfare and the safety of professionals were promoted along with an overall regard for the relevant legislation. This study demonstrates a number of the challenges associated with deer transport and related activities. The paucity of specific legislation regarding the management and transport of farmed deer and the absence of European standard procedures have created a lack of harmonisation in transport procedures, ultimately jeopardising the welfare of deer.