Acoustic-structure interaction problems. Final report
Love, E.; Taylor, R.L.
1993-12-01
The purpose of this report is to compare and evaluate different numerical methods for solving problems of interaction between elastic solids and acoustic fluids. In particular, we concentrate our efforts on solution techniques involving the finite element method. To that end, in Chapter 2 we discuss different options for analysis of infinite fluids. In particular, the method of mesh trunction and the use of radiation elements and the use of infinite elements are discussed. Also discussed is the analysis of scattering from rigid boundaries. Chapter 3 is a brief discussion of finite element formulations for elastic solids. We review the development, of two dimensional plane strain elements and one dimensional plate and shell elements. In Chapter 4, there is a discussion of the method used to couple the solid and the fluid. We give examples for solution of scattering of pressure waves from thin elastic shell structures. Chapter 5 is a brief conclusion of results and includes recommendations for the best methods of solution and additional research.
Topological Design for Acoustic-Structure Interaction Problems with a Mixed Finite Element Method
Yoon, Gil Ho; Jensen, Jakob Søndergaard; Sigmund, Ole
2006-01-01
to subdomain interfaces evolving during the optimization process. In this paper, we propose to use a mixed finite element formulation with displacements and pressure as primary variables (u/p formulation) which eliminates the need for explicit boundary representation. In order to describe the...... dimensional acoustic-structure interaction problems are optimized to show the validity of the proposed method....
Computational and experimental techniques for coupled acoustic/structure interactions.
Sumali, Anton Hartono; Pierson, Kendall Hugh; Walsh, Timothy Francis; Dohner, Jeffrey Lynn; Reese, Garth M.; Day, David Minot
2004-01-01
This report documents the results obtained during a one-year Laboratory Directed Research and Development (LDRD) initiative aimed at investigating coupled structural acoustic interactions by means of algorithm development and experiment. Finite element acoustic formulations have been developed based on fluid velocity potential and fluid displacement. Domain decomposition and diagonal scaling preconditioners were investigated for parallel implementation. A formulation that includes fluid viscosity and that can simulate both pressure and shear waves in fluid was developed. An acoustic wave tube was built, tested, and shown to be an effective means of testing acoustic loading on simple test structures. The tube is capable of creating a semi-infinite acoustic field due to nonreflecting acoustic termination at one end. In addition, a micro-torsional disk was created and tested for the purposes of investigating acoustic shear wave damping in microstructures, and the slip boundary conditions that occur along the wet interface when the Knudsen number becomes sufficiently large.
The Interaction Programming Problem
LI Rong-sheng; CHENG Ying
2001-01-01
Based upon the research to the economic equilibrium problems, we present a kind of new mathematical programming problem-interaction programming problem (abbreviated by IPP). The IPP is composed of two or multiple parametric programming problems which is interrelated with each other. The IPP reflects the equality and mutual benefit relationship between two (or among multiple) economic planners in an economic system. In essence, the IPP is similar to the generalized Nash equilibria (GNE) game which has been given several names in the literature: social equilibria games, pseudo-Nash equilibria games, and equilibrium programming problems. In this paper, we establish the mathematical model and some basic concepts to the IPP. We investigate the structure and the properties of the IPP. We also give a necessary and sufficient conditions for the existence of the equilibrium points to a kind of linear IPP.
Interactive problem solving using LOGO
Boecker, Heinz-Dieter; Fischer, Gerhard
2014-01-01
This book is unique in that its stress is not on the mastery of a programming language, but on the importance and value of interactive problem solving. The authors focus on several specific interest worlds: mathematics, computer science, artificial intelligence, linguistics, and games; however, their approach can serve as a model that may be applied easily to other fields as well. Those who are interested in symbolic computing will find that Interactive Problem Solving Using LOGO provides a gentle introduction from which one may move on to other, more advanced computational frameworks or more
Low-Frequency Acoustic-Structure Analysis Using Coupled FEM-BEM Method
Jinlong Feng; Xiaoping Zheng; Haitao Wang; HongTao Wang; Yuanjie Zou; Yinghua Liu; Zhenhan Yao
2013-01-01
A numerical algorithm based on finite element method (FEM) and boundary element method (BEM) is proposed for the analyses of acoustic-structure coupled problems. By this algorithm, the structural domain and the acoustic domain are modelled by FEM and BEM, respectively, which are coupled with each other through the consideration of the appropriate compatibility and equilibrium conditions on the interface of the two domains. To improve the computational efficiency, the adaptive cross approximat...
Interactive Scenario Analysis of Exhaustible Resource Problems
Caplan, Arthur J.; Gilbert, John
2006-01-01
We provide several interactive models that can be used in an intermediate- or graduate-level, natural-resource economics course to numerically solve a host of exhaustible-resource problems, and thereby help to verify the intuition and symbolic solutions typically provided in textbooks. Examples are drawn from Tietenberg (2006).
Fluid Structure Interaction for Hydraulic Problems
Fluid Structure interaction plays an important role in engineering applications. Physical phenomena such as flow induced vibration in nuclear industry, fuel sloshing tank in automotive industry or rotor stator interaction in turbo machinery, can lead to structure deformation and sometimes to failure. In order to solve fluid structure interaction problems, the majority of numerical tests consists in using two different codes to separately solve pressure of the fluid and structural displacements. In this paper, a unique code with an ALE formulation approach is used to implicitly calculate the pressure of an incompressible fluid applied to the structure. The development of the ALE method as well as the coupling in a computational structural dynamic code, allows to solve more large industrial problems related to fluid structure coupling. (authors)
Interactive Problem Solving Tutorials Through Visual Programming
Undreiu, Lucian; Schuster, David; Undreiu, Adriana
2008-10-01
We have used LabVIEW visual programming to build an interactive tutorial to promote conceptual understanding in physics problem solving. This programming environment is able to offer a web-accessible problem solving experience that enables students to work at their own pace and receive feedback. Intuitive graphical symbols, modular structures and the ability to create templates are just a few of the advantages this software has to offer. The architecture of an application can be designed in a way that allows instructors with little knowledge of LabVIEW to easily personalize it. Both the physics solution and the interactive pedagogy can be visually programmed in LabVIEW. Our physics pedagogy approach is that of cognitive apprenticeship, in that the tutorial guides students to develop conceptual understanding and physical insight into phenomena, rather than purely formula-based solutions. We demonstrate how this model is reflected in the design and programming of the interactive tutorials.
Some studies on fluid structure interaction problems
In this report a review of fluid structure interaction problems has been made. The areas of development work on liquid container design, seismic response of pressure supression pool in a nuclear power plant, analysis of submerged structures and pulse induced vibration in coupled fluid shell systems are discussed. The areas of application for analysis of moderator filled calandria of a pressurised heavy water reactor (PHWR) and analysis of calandria tube/pressure tube/guide tube in case of overpressurisation of calandria are emphasised. A brief review of various methods for solving fluid structure interaction problem is then undertaken. A formulation for two dimensional and axi-symmetric problems based on finite element method using pressure field in fluid and displacement field in structure is presented along with a number of problems solved using this method. Implementation of implicit explicit mixed time integration scheme for solution of equations of the coupled field is discussed. A comparison has been made between present approach and structure mechanics priority approach. (author). 8 figs., 36 refs
ERROR ANALYSIS OF COMPOSITE SHOCK INTERACTION PROBLEMS.
LEE,T.MU,Y.ZHAO,M.GLIMM,J.LI,X.YE,K.
2004-07-26
We propose statistical models of uncertainty and error in numerical solutions. To represent errors efficiently in shock physics simulations we propose a composition law. The law allows us to estimate errors in the solutions of composite problems in terms of the errors from simpler ones as discussed in a previous paper. In this paper, we conduct a detailed analysis of the errors. One of our goals is to understand the relative magnitude of the input uncertainty vs. the errors created within the numerical solution. In more detail, we wish to understand the contribution of each wave interaction to the errors observed at the end of the simulation.
MONITORING OF THE METAL STRUCTURAL STATE BY ACOUSTICAL STRUCTURAL NOISE
V. V. Muraviev
2015-03-01
Full Text Available To determine the structural state of the metal as an informative parameter the structural acoustic noise is proposed. The paper represents the experimental results of the use at acoustical structural noise for the determination at the structural state of carbon pipe steels exposed by heat treatment, corrosion and tensile loads. The effect of grain size, corrosion and tensile loads on the level of structural noise is discussed.
Wavelet analysis of baryon acoustic structures in the galaxy distribution
Arnalte-Mur, P.; Labatie, A.; Clerc, N.; Martínez, V. J.; Starck, J.-L.; Lachièze-Rey, M.; Saar, E; Paredes, S.
2012-01-01
Baryon Acoustic Oscillations (BAO) are a feature imprinted in the density field by acoustic waves travelling in the plasma of the early universe. Their fixed scale can be used as a standard ruler to study the geometry of the universe. BAO have been previously detected using correlation functions and power spectra of the galaxy distribution. In this work, we present a new method for the detection of the real-space structures associated with this feature. These baryon acoustic structures are sp...
A partitioned scheme for fluid-composite structure interaction problems
Bukac, Martina; Canic, Suncica; Muha, Boris
2014-01-01
We present a loosely-coupled partitioned scheme for a benchmark problem in fluid-composite structure interaction. The benchmark problem proposed here consists of an incompressible, viscous fluid interacting with a composite structure that consists of two layers: a thin elastic layer which is in contact with the fluid, and a thick elastic layer which sits on top of the thin layer. The motivation comes from fluid-structure interaction (FSI) in hemodyam- ics. The equations of linear elasticity a...
Low-Frequency Acoustic-Structure Analysis Using Coupled FEM-BEM Method
Jinlong Feng
2013-01-01
Full Text Available A numerical algorithm based on finite element method (FEM and boundary element method (BEM is proposed for the analyses of acoustic-structure coupled problems. By this algorithm, the structural domain and the acoustic domain are modelled by FEM and BEM, respectively, which are coupled with each other through the consideration of the appropriate compatibility and equilibrium conditions on the interface of the two domains. To improve the computational efficiency, the adaptive cross approximation (ACA approach is incorporated into the proposed algorithm to deal with the nonsymmetric and fully populated matrices resulting from the coupling of the FEM and BEM. The validity and the high efficiency of the present approach are demonstrated by two examples.
On the Cauchy Problem Describing an Electron-Phonon Interaction
Jo(a)o-Paulo DIAS; Mário FIGUEIRA; Filipe OLIVEIRA
2011-01-01
In this paper, a model is derived to describe a quartic anharmonic interatomic interaction with an external potential involving a pair electron-phonon. The authors study the corresponding Cauchy Problem in the semilinear and quasilinear cases.
Pregnancy Problems, Postpartum Depression, and Early Mother-Infant Interactions.
Field, Tiffany; And Others
1985-01-01
Mothers observed at 3 to 5 months postpartum interacting with their infants were given attitude questionnaires. Mothers who had reported preganancy problems were more depressed and anxious and expressed more punitive childrearing attitudes than mothers not reporting pregnancy problems. (Author/NH)
Numerical approximation of fluid-structure interaction problems
Sváček P.
2008-11-01
Full Text Available This paper is devoted to numerical approximations of fluid-structure interaction problems. Namely the problem of interaction of turbulent flow over flexibly supported airfoil is addressed. In order to model the turbulence effects the flow is described by Reynolds Averaged Navier-Stokes (RANS equations. The Reynolds equations and the turbulence model is numerically approximated by the finite element method. In order to avoid spurious oscillations stabilization procedures are applied. The application of the developed numerical method is shown in several numerical experiments.
THE INTERACTION PROBLEM BETWEEN THE ELASTIC LINE INCLUSIONS
陶昉敏; 张明焕; 汤任基
2002-01-01
Using the engineering model of elastic line inclusion and the basic solutions of a single inclusion, the interaction problem between line inclusions in an elastic solid was investigated. A set of standard Cauchy-type singular equations of the problem was presented. The stress intensity factors at points of inclusions and the interface stresses of two sides of the inclusion were calculated. Several numerical examples were given. The results could be regarded as a reference to engineering.
Cheating for Problem Solving: A Genetic Algorithm with Social Interactions
Lahoz-Beltra, Rafeal; Aickelin, Uwe
2010-01-01
We propose a variation of the standard genetic algorithm that incorporates social interaction between the individuals in the population. Our goal is to understand the evolutionary role of social systems and its possible application as a non-genetic new step in evolutionary algorithms. In biological populations, ie animals, even human beings and microorganisms, social interactions often affect the fitness of individuals. It is conceivable that the perturbation of the fitness via social interactions is an evolutionary strategy to avoid trapping into local optimum, thus avoiding a fast convergence of the population. We model the social interactions according to Game Theory. The population is, therefore, composed by cooperator and defector individuals whose interactions produce payoffs according to well known game models (prisoner's dilemma, chicken game, and others). Our results on Knapsack problems show, for some game models, a significant performance improvement as compared to a standard genetic algorithm.
Topology optimization of fluid-structure-interaction problems in poroelasticity
Andreasen, Casper Schousboe; Sigmund, Ole
2013-01-01
This paper presents a method for applying topology optimization to fluid-structure interaction problems in saturated poroelastic media. The method relies on a multiple-scale method applied to periodic media. The resulting model couples the Stokes flow in the pores of the structure with the...
Interactive Drawing Therapy and Chinese Migrants with Gambling Problems
Zhang, Wenli; Everts, Hans
2012-01-01
Ethnic Chinese migrants in a country like New Zealand face a range of well-documented challenges. A proportion of such migrants find that recreational gambling turns into a pernicious gambling problem. This issue is addressed through illustrated case studies of Interactive Drawing Therapy, a drawing-based modality of therapy that facilitates…
Mathematical problems of interaction of different dimensional physical fields
In the paper we consider mathematical problem of interaction of different dimensional physical fields for complex composite structures. We investigate the mixed transmission problem arising in the model of fluid-solid acoustic interaction when a piezo-ceramic elastic body (Ω+) is embedded in an unbounded fluid (Ω−). The corresponding physical process is described by boundary-transmission problems for second order partial differential equations. In particular, in the bounded domain Ω+ we have 4 × 4 dimensional matrix strongly elliptic second order partial differential equation, while in the unbounded complement domain Ω− we have a scalar Helmholtz equation describing an acoustic wave propagation. The physical kinematic and dynamic relations mathematically are described by appropriate boundary and transmission conditions. With the help of the potential method and theory of pseudodifferential equations the uniqueness and existence theorems are proved in Sobolev-Slobodetski spaces
Social interaction as a heuristic for combinatorial optimization problems
Fontanari, Jose F
2010-01-01
We investigate the performance of a variant of Axelrod's model for dissemination of culture - the Adaptive Culture Heuristic (ACH) - on solving an NP-Complete optimization problem, namely, the classification of binary input patterns of size $F$ by a Boolean Binary Perceptron. In this heuristic, $N$ agents, characterized by binary strings of length $F$ which represent possible solutions to the optimization problem, are fixed at the sites of a square lattice and interact with their nearest neighbors only. The interactions are such that the agents' strings (or cultures) become more similar to the low-cost strings of their neighbors resulting in the dissemination of these strings across the lattice. Eventually the dynamics freezes into a homogeneous absorbing configuration in which all agents exhibit identical solutions to the optimization problem. We find through extensive simulations that the probability of finding the optimal solution is a function of the reduced variable $F/N^{1/4}$ so that the number of agen...
Inverse problem for multi-body interaction of nonlinear waves
Marruzzo, Alessia; Antenucci, Fabrizio; Pagnani, Andrea; Leuzzi, Luca
2016-01-01
The inverse problem is studied in multi-body systems with nonlinear dynamics representing, e.g., phase-locked wave systems, standard multimode and random lasers. Using a general model for four-body interacting complex-valued variables we test two methods based on pseudolikelihood, respectively with regularization and with decimation, to determine the coupling constants from sets of measured configurations. We test statistical inference predictions for increasing number of sampled configurations and for an externally tunable {\\em temperature}-like parameter mimicing real data noise and helping minimization procedures. Analyzed models with phasors and rotors are generalizations of problems of real-valued spherical problems (e.g., density fluctuations), discrete spins (Ising and vectorial Potts) or finite number of states (standard Potts): inference methods presented here can, then, be straightforward applied to a large class of inverse problems.
Sensitivity analysis of fluid-structure interaction problems
Interactions between solids and fluids (FSI) have been a topic of interest for engineers for many years. The behavior of vessels subject to wave loads, of planes in flight condition as well as submarine or transmission lines are but a few examples. In an attempt to address these problems, the present paper presents a formulation which allows to treat interactions between an incompressible flow and a structure undergoing large displacements. We assume existence and unicity of the solution. The interested reader is referred, for a mathematical discussion of existence and unicity. The approach to coupling can be addressed in two ways: weakly-coupled methods for which algorithms for structure and fluid are segregated, as is commonly done for simplicity and often because engineers have access to existing structural and fluid codes; and tightly-coupled or monolithic methods, for which the formulation guarantees satisfaction of equilibrium of the interface between the fluid and the solid. The latter has been chosen as it allows for quadratic convergence of Newton's method. The paper begins with the description of the steady state governing equations for laminar incompressible fluids, hyperelastic solid behaviour, pseudo-solid mapping and fluid-structure interfaces. The weak forms of the equations are then presented. We proceed with the description of the continuous sensitivity equations for fluid-structure interactions problems. The following sections detail the adaptive finite element procedure for the fluid-structure interaction and sensitivity problems. Results are presented and the paper ends with conclusions and discussions. (author)
An interactive approach to the stochastic multiobjective allocation problem
Maciej Nowak
2015-03-01
Full Text Available The paper considers the stochastic multiobjective allocation problem. An assumption is made that a particular resource should be allocated to T projects. The specified level of each goal (along with the known probabilities can be obtained based on the amount of the resources allocated. We will propose an identification strategy procedure that the decision maker can implement. Our technique combines multiobjective dynamic programming and an interactive approach. First, efficient strategies are identified using Bellman's principle applied to the multiobjective problem. Next, a dialog procedure is used to find a solution that is satisfactory for the decision maker. A numerical example is presented to show how the procedure can be applied.
Exacerbating the cosmological constant problem with interacting dark energy
Marsh, M. C. David
2016-01-01
Future cosmological surveys will probe the expansion history of the universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e. the cosmological constant problem (c.c.p.), but can make it spectacularly worse. We show that this is the case for 'interacting dark energy' models in which the masses of the dark matter states depend on the dark energy sector. If realised in nature, these models have far-reaching implic...
Electroreflectance and the problem of studying plasma-surface interactions
A long standing problem in low-temperature plasma discharge physics is to understand in detail the mutual interaction of real exposed surfaces (electrodes) with the reactive plasma environment. In particular, one wishes to discern the influence of these surfaces on the plasma parameters given their contributions from secondary electrons and ions. This paper briefly reviews the known surface interaction processes as well as currently available diagnostics to study the interface between plasmas and surfaces. Next comes a discussion describing the application of plasma-modulated electroreflectance to this research and some potential experimental techniques
TPLOT: an interactive data management system for transient problems
This report describes the use of an interactive data management system suitable for post-processing of transient structural problems. The system is designed for IBM compatible environment (Time Sharing Option command procedures TSO) and makes use of PLOT-10 (Tektronix) for graphical output (time plots). Interfaces are provided for experimental data and for various programs used in fast reactor safety analysis (EURDYN, SEURBNUK, ASTARTE, FRAP-T5, RODSWELL, SIMMER, TRACRUF, PHEAT, JOULE). A users' manual describes the command language used for interactive data processing. Some examples are given to illustrate the system
Exacerbating the cosmological constant problem with interacting dark energy
Marsh, M C David
2016-01-01
Future cosmological surveys will probe the expansion history of the universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e. the cosmological constant problem (c.c.p.), but can make it spectacularly worse. We show that this is the case for 'interacting dark energy' models in which the masses of the dark matter states depend on the dark energy sector. If realised in nature, these models have far-reaching implications for proposed solutions to the c.c.p. that require the number of vacua to exceed the fine-tuning of the vacuum energy density. We show that current estimates of the number of flux vacua in string theory, $N_{\\rm vac} \\sim {\\cal O}(10^{272,000})$, is far too small to realise certain simple models of interacting dark energy \\emph{and} solve the cosmological constant problem anthropically. These models admit distinctive observational signatures that can be targeted by future gamma-ray observatories, hence making it pos...
Three-nucleon problem: trinucleon bound states and trinucleon interactions
The assumptions underlying the formulation and solution of the Schroedinger equation for three nucleons in configuration space are reviewed, in conjunction with those qualitative aspects of the two-nucleon problem which are important. The geometrical features of the problem and the crucial role of the angular momentum barrier are developed. The boundary conditions for scattering are discussed qualitatively, and the Faddeev-Noyes equation is motivated. The method of splines and orthogonal collocation are shown to provide convenient techniques for generating numerical solutions. Properties of the many numerical solutions for the bound states and zero-energy scattering states are discussed. The evidence for three-body forces is reviewed, and the results of the recent calculations including such forces are discussed. The importance of electromagnetic interactions in the three-nucleon systems is motivated. Relativistic corrections and meson-exchange currents are discussed in the context of ''rules of scale'', and the pion-exchange currents of nonrelativistic order are derived. The experimental results for trinucleon electromagnetic interactions are reviewed, including recent tritium data. Conclusions are presented. 56 refs., 23 figs
Interaction Network Estimation: Predicting Problem-Solving Diversity in Interactive Environments
Eagle, Michael; Hicks, Drew; Barnes, Tiffany
2015-01-01
Intelligent tutoring systems and computer aided learning environments aimed at developing problem solving produce large amounts of transactional data which make it a challenge for both researchers and educators to understand how students work within the environment. Researchers have modeled student-tutor interactions using complex networks in…
Visualization of protein interaction networks: problems and solutions
Agapito Giuseppe
2013-01-01
Full Text Available Abstract Background Visualization concerns the representation of data visually and is an important task in scientific research. Protein-protein interactions (PPI are discovered using either wet lab techniques, such mass spectrometry, or in silico predictions tools, resulting in large collections of interactions stored in specialized databases. The set of all interactions of an organism forms a protein-protein interaction network (PIN and is an important tool for studying the behaviour of the cell machinery. Since graphic representation of PINs may highlight important substructures, e.g. protein complexes, visualization is more and more used to study the underlying graph structure of PINs. Although graphs are well known data structures, there are different open problems regarding PINs visualization: the high number of nodes and connections, the heterogeneity of nodes (proteins and edges (interactions, the possibility to annotate proteins and interactions with biological information extracted by ontologies (e.g. Gene Ontology that enriches the PINs with semantic information, but complicates their visualization. Methods In these last years many software tools for the visualization of PINs have been developed. Initially thought for visualization only, some of them have been successively enriched with new functions for PPI data management and PIN analysis. The paper analyzes the main software tools for PINs visualization considering four main criteria: (i technology, i.e. availability/license of the software and supported OS (Operating System platforms; (ii interoperability, i.e. ability to import/export networks in various formats, ability to export data in a graphic format, extensibility of the system, e.g. through plug-ins; (iii visualization, i.e. supported layout and rendering algorithms and availability of parallel implementation; (iv analysis, i.e. availability of network analysis functions, such as clustering or mining of the graph, and the
Land-Atmosphere Interactions: Successes, Problems and Prospects
Sud, Y. C.; Mocko, D. M.
1999-01-01
After two decades of active research, a much better understanding of the broader role of biospheric processes on the local climate has emerged. A surface-albedo increase, particularly in desert border regions of the subtropics (as well as the deforested tropical regions), leads to a net surface energy deficit, which in turn leads to a relative sinking and reduced rainfall. On the other hand, studies of the influence of altered ratios of evapotranspiration and sensible fluxes, in situations where the net solar income is unchanged, show that evapotranspiration is a more desirable flux for increased precipitation and vitality of the biosphere. Besides providing water vapor and convective available potential energy (CAPE) to the lower troposphere, evapotranspiration helps in building larger CAPE before "turning on" the moist-convection. Larger CAPE in the lower troposphere enables convection to reach into the deeper atmosphere thereby heating the upper troposphere; indeed, moist-convection is also accompanied by the evaporation of falling precipitation that cools and moistens the lower atmosphere. While convective, as opposed to stratiform, precipitation reduces the fractional cloud cover; it also allows more solar radiation to reach the surface thereby invigorating surface fluxes. These, together with moist convection and associated downdrafts help to maintain the characteristic upper temperature limit(s) of the moist-land as well as oceanic regions. Regardless of the above understanding, several important problems continue to hinder the accurate simulation of a realistic land atmosphere interaction in a numerical model (both GCM and/or Meso-scale models). Among the unsolved problems are parameterization of sub-grid scale land processes that include small-scale variability of soil moisture, snow-cover and snow-physics, the biodiversity of the biosphere, orography, local drainage characteristics under natural conditions, and surface flow over the natural terrain. A
The Interfacial Interaction Problem in Complex Multiple Porosity Fractured Reservoirs
Suarez-Arriaga, Mario-Cesar
2003-04-01
Many productive reservoirs (oil, gas, water, geothermal) are associated to natural fracturing. Fault zones and fractures act as open networks for fluid and energy flow from depth. Their petrophysical parameters are heterogeneous and randomly distributed, conforming extremely complex natural systems. Here, the simultaneous heat and mass flows are coupled to the deformation of thermoporoelastic rocks. The system's volume is divided into N interacting continua, each one occupying a region of space Vn wrapped by a surface Sn (n=1,N). The mass flow is represented by: ∂/∂t ∫ Vn ρf φdV + ∫ Sn F⃗M ṡ n⃗dS = ∫ Vn qMdV (3) Taking into account a non-isothermal process the coupled equation of energy is: ∂/∂t ∫ Vn [φρf hf + (1 - φ)ρrhr]dV + ∫ Sn F⃗E ṡ n⃗dS = ∫ Vn qEdV (4) Where t means time, φ is porosity, ρf, ρr are fluid and rock densities, F⃗M and F⃗E are total mass and energy flows, qM and qE are volumetric mass and energy extracted or injected into Vn, hf and hr are specific enthalpies for fluid and rock respectively. Rock deformation is coupled through the equation: ∇⃗ ṡ (ρf/μK ṡ ∇⃗pφ)Vn = φ (Dtρf + ρf/VφdVφ/dt)Vn (5) K is the absolute permeability tensor, μ means dynamic fluid viscosity, Dt is a total derivative, pφ is pore pressure and Vφ is the volume of pores in Vn. The N media interact with each other, every one has its own parameters and its own interporosity flow. Modelling these coupled phenomena requires to average highly contrasting physical properties, independently of the method used in the solution of equations. A lot of attention has been devoted to develop realistic numerical models to describe flows in reservoirs under exploitation. But to the best of our knowledge very little attention has been focused on the problem of interfacial interaction and averaging petrophysical parameters in multiple porosity reservoirs.
Repulsive interactions in quantum Hall systems as a pairing problem
Ortiz, G.; Nussinov, Z.; Dukelsky, J.; Seidel, A.
2013-10-01
A subtle relation between quantum Hall physics and the phenomenon of pairing is unveiled. By use of second quantization, we establish a connection between (i) a broad class of rotationally symmetric two-body interactions within the lowest Landau level and (ii) integrable hyperbolic Richardson-Gaudin-type Hamiltonians that arise in (px+ipy) superconductivity. Specifically, we show that general Haldane pseudopotentials (and their sums) can be expressed as a sum of repulsive noncommuting (px+ipy)-type pairing Hamiltonians. The determination of the spectrum and individual null spaces of each of these noncommuting Richardson-Gaudin-type Hamiltonians is nontrivial yet is Bethe ansatz solvable. For the Laughlin sequence, it is observed that this problem is frustration free and zero-energy ground states lie in the common null space of all of these noncommuting Hamiltonians. This property allows for the use of a new truncated basis of pairing configurations in which to express Laughlin states at general filling factors. We prove separability of arbitrary Haldane pseudopotentials, providing explicit expressions for their second quantized forms, and further show by explicit construction how to exploit the topological equivalence between different geometries (disk, cylinder, and sphere) sharing the same topological genus number, in the second quantized formalism, through similarity transformations. As an application of the second quantized approach, we establish a “squeezing principle” that applies to the zero modes of a general class of Hamiltonians, which includes but is not limited to Haldane pseudopotentials. We also show how one may establish (bounds on) “incompressible filling factors” for those Hamiltonians. By invoking properties of symmetric polynomials, we provide explicit second quantized quasihole generators; the generators that we find directly relate to bosonic chiral edge modes and further make aspects of dimensional reduction in the quantum Hall systems
Peer Interaction, Problem-Solving, and Cognition: Multidisciplinary Perspectives.
Webb, Noreen M., Ed.
1989-01-01
Current thinking of researchers from different disciplines about interaction among students in educational settings and the potential of peer interaction for learning and cognitive development is discussed. Topics of the eight papers presented include: potential outcomes of peer interaction, its nature, peer learning settings, and factors shaping…
Seal, Kala Chand; Przasnyski, Zbigniew H.; Leon, Linda A.
2010-01-01
Do students learn to model OR/MS problems better by using computer-based interactive tutorials and, if so, does increased interactivity in the tutorials lead to better learning? In order to determine the effect of different levels of interactivity on student learning, we used screen capture technology to design interactive support materials for…
A minmax problem for parabolic systems with competitive interactions
Sanjay Chawla
1999-12-01
Full Text Available In this paper we model the evolution and interaction between two competing populations as a system of parabolic partial differential equations. The interaction between the two populations is quantified by the presence of non-local terms in the system of equations. We model the whole system as a two-person zero-sum game where the gains accrued by one population necessarily translate into the others loss. For a suitably chosen objective functional(pay-off we establish and characterize the saddle point of the game. The controls(strategies are kernels of the interaction terms.
An interacting replica approach applied to the traveling salesman problem
Sun, Bo; Leonard, Blake; Ronhovde, Peter; Nussinov, Zohar
2014-01-01
We present a physics inspired heuristic method for solving combinatorial optimization problems. Our approach is specifically motivated by the desire to avoid trapping in metastable local minima- a common occurrence in hard problems with multiple extrema. Our method involves (i) coupling otherwise independent simulations of a system ("replicas") via geometrical distances as well as (ii) probabilistic inference applied to the solutions found by individual replicas. The {\\it ensemble} of replica...
Early Father-Child Interactions and Behaviour Problems
Domoney, J.
2013-01-01
Many development trajectories leading to maladaptive outcomes begin in infancy and toddlerhood. With more fathers caring for their children from a younger age there is a need to understand the associations between paternal behaviour and child development. This thesis will explore the relationship between father-child interaction and child outcomes in the early years. Part one is a review of the literature looking at the association between father-child interaction in the preschool years and c...
Molenaar, Dylan; Middeldorp, Christel; van Beijsterveldt, Toos; Boomsma, Dorret I
2015-01-01
This study tested for Genotype × Environment (G × E) interaction on behavioral and emotional problems in children using new methods that do not require identification of candidate genes or environments, can distinguish between interaction with shared and unique environment, and are insensitive to scale effects. Parental ratings of problem behavior from 14,755 twin pairs (5.3 years, SD = 0.22) indicated G × E interaction on emotional liability, social isolation, aggression, attention problems, dependency, anxiety, and physical coordination. Environmental influences increased in children who were genetically more predisposed to problem behavior, with ~20% of the variance due to G × E interaction (8% for anxiety to 37% for attention problems). Ignoring G × E interaction does not greatly bias heritability estimates, but it does offer a comprehensive model of the etiology for childhood problems. PMID:26509842
A minmax problem for parabolic systems with competitive interactions
Sanjay Chawla
1999-01-01
In this paper we model the evolution and interaction between two competing populations as a system of parabolic partial differential equations. The interaction between the two populations is quantified by the presence of non-local terms in the system of equations. We model the whole system as a two-person zero-sum game where the gains accrued by one population necessarily translate into the others loss. For a suitably chosen objective functional(pay-off) we establish and characterize the sadd...
Acanthamoeba and Fusarium interactions: A possible problem in keratitis.
Nunes, Thais Esther Teixeira; Brazil, Nathalya Tesch; Fuentefria, Alexandre Meneghello; Rott, Marilise Brittes
2016-05-01
The incidence of Acanthamoeba and Fusarium species has increased in contact lens-related infectious keratitis. They share several environments and cases of co-infection have been reported. The interaction between the amoebae and other microorganisms may result in significant changes for both, like increased virulence in mammalian hosts. In this study, we evaluated the interaction of three Acanthamoeba castellanii strains with Fusarium conidia and the possible implications on keratitis. F. conidia were internalized by A. castellanii strains and were able to germinate inside the amoebae. The co-culture with the live amoebae, as well as the amoebal culture supernatant and lysate, increased the fungal growth significantly. Moreover, live F. solani and its culture supernatant enhanced the survival of amoebae, but in a different way in each amoebal strain. The encystment of the A. castellanii strain re-isolated from rat lung was increased by the fungus. These results show that A. castellanii and F. solani interaction may have an important influence on survival of both, and specially indicate a possible effect on virulence characteristics of these microorganisms. These data suggest that the A. castellanii-F. solani interaction may cause severe impacts on keratitis. PMID:26851515
Textbook treatments of quantum electromagnetic interaction: pedagogical and conceptual problems
Fraile-Peláez, F. Javier
2001-07-01
In this paper we review and discuss the approaches used, almost universally, in textbooks dealing with quantum mechanics, and particularly those focused on optoelectronics devices, to explain the atom-field interactions. For this purpose, a true understanding and careful use of the first-order perturbation theory are necessary. By providing two alternative full derivations of the absorption/emission processes when the radiation is in a coherent multimode state, we highlight a number of conceptual and didactical failures in the usual textbook presentations, and propose more suitable and convincing strategies to improve them.
Use of Lanczos vectors in fluid/structure interaction problems
The goals of any numerical computational technique used for the solution of structural acoustics problems in the exterior infinite domain should be of accuracy with rapid convergence, robustness, and computational efficiency. A computer program has been developed to achieve each of these three goals. Accuracy and robustness in the numerical representation of the integral equations used to represent the infinite fluid was attained through the use of boundary element implementations of the surface Helmholtz integral equations. The computational efficiency was resolved through the use of Lanczos vectors to model the deformation characteristics of the structure. The authors have developed collocation and variational techniques to overcome the difficulties previously encountered in the numerical implementation of the hypersingular integral operator. The Cauchy singularity present in the integral formulation is made numerically amenable through the use of tangential derivatives in both the collocation and variational techniques. The variational approach has the advantage that the resulting added fluid mass term is symmetric and combines efficiently with a finite element approximation of the structural elastic response. Several different strategies making use of the Lanczos vectors have been investigated. The first involved the use of Lanczos vectors solely to characterize the structural response. This reduced form of the structural dynamical matrix was then substituted back into a Burton and Miller formulation of the acoustic problem. The second strategy investigated involved forming the complex Lanzcos vectors of the dynamical matrix formed from the addition of a symmetrical added fluid matrix to the structural mass matrix. The size of resultant matrix equation set solved at each frequency for this strategy is determined by the number of Lanczos vectors used. 19 refs., 10 figs., 2 tabs
Kook, Junghwan; Jensen, Jakob Søndergaard
2014-01-01
The aim of this paper is to investigate the enhancement of the damping ratio of a structure with embedded microbeam resonators in air-filled internal cavities. In this context, we discuss theoretical aspects in the framework of the effective modal damping ratio (MDR) and derive an approximate rel...
Acoustic-structural interaction in human vocal tract prolonged by a tube
Radolf, Vojtěch; Horáček, Jaromír
Praha: Institute of Thermomechanics AS CR, 2014 - (Zolotarev, I.; Pešek, L.), s. 53-58 ISBN 978-80-87012-54-3. [DYMAMESI 2014. Praha (CZ), 25.11.2014-26.11.2014] R&D Projects: GA ČR GPP101/12/P579 Institutional support: RVO:61388998 Keywords : biomechanics of voice * phonation into tubes * formant frequency Subject RIV: BI - Acoustics
Gavrilushkina O.P.; Malova A.A.; Pankratova M.V.
2012-01-01
The article presents the review of foreign and national investigations concerning genesis and specificity of interactions in children with difficulties in social contacts at early stages of ontogenesis. The following aspects of the problem were regarded: specificity of social interaction in children with autism spectrum disorder and mental retardation; peculiarities of child social interaction as depending on ethnic and gender attributes; factors determining the quality of interaction and so...
Cluster approach to corrosion inhibition problems: interaction studies
The interaction energies of 3,5 di-methyl pyridine (A) and 2,4 di-methyl pyridine (B) on the (1 0 0) surface of body-centered cubic (bcc) iron were determined via a cluster model and ab initio quantum chemical calculations at density functional theory level. The obtained energies were used to compare the inhibition behavior of these molecules for iron corrosion in hydrochloric acid solution. The iron surface and its adsorption sites (on-top, bridge, hollow) were considered as some clusters taken from two-layered planes, i.e. Fe1(1), Fe4(2,2), and Fe5(4,1). So, the process for which quantum chemical calculations was carried out consists of adsorption of molecule A (B) on these clusters. Also for these molecules, two adsorption modes (planar adsorption (P) via pyridine ring and vertical adsorption (V) through nitrogen atom) with three azimuthal angles (0, 45, and 90 A ) were applied. Comparison of the theoretical and previous experimental results shows a reasonably good correlation which, in turn, supports the reliability of the method employed here
A Non-smooth Nonlinear Conjugate Gradient Method for Interactive Contact Force Problems
Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny
Interactive rigid body simulation is important for robot simulation and virtual design. A vital part of the simulation is the computation of contact forces. This paper addresses the contact force problem, as used in interactive simulation. The contact force problem can be formulated in the form of...... a nonlinear complementarity problem (NCP), which can be solved using an iterative splitting method, such as the projected Gauss–Seidel (PGS) method. We present a novel method for solving the NCP problem by applying a Fletcher–Reeves type nonlinear nonsmooth conjugate gradient (NNCG) type method. We...
An interactive problem-solving approach to teach traumatology for medical students
Abu-Zidan, Fikri M; Elzubeir, Margaret A
2010-01-01
Aim We aimed to evaluate an interactive problem-solving approach for teaching traumatology from perspectives of students and consider its implications on Faculty development. Methods A two hour problem-solving, interactive tutorial on traumatology was structured to cover main topics in trauma management. The tutorial was based on real cases covering specific topics and objectives. Seven tutorials (5-9 students in each) were given by the same tutor with the same format for fourth and fifth yea...
Interactive Computer Based Assessment Tasks: How Problem-Solving Process Data Can Inform Instruction
Zoanetti, Nathan
2010-01-01
This article presents key steps in the design and analysis of a computer based problem-solving assessment featuring interactive tasks. The purpose of the assessment is to support targeted instruction for students by diagnosing strengths and weaknesses at different stages of problem-solving. The first focus of this article is the task piloting…
Lee, Chwee Beng
2010-01-01
This study examines the interactions between problem solving and conceptual change in an elementary science class where students build system dynamic models as a form of problem representations. Through mostly qualitative findings, we illustrate the interplay of three emerging intervening conditions (epistemological belief, structural knowledge…
Ceberio, Mikel; Almudí, José Manuel; Franco, Ángel
2016-01-01
In recent years, interactive computer simulations have been progressively integrated in the teaching of the sciences and have contributed significant improvements in the teaching-learning process. Practicing problem-solving is a key factor in science and engineering education. The aim of this study was to design simulation-based problem-solving…
Sakawa, M.; Kato, K.
2009-01-01
This paper considers stochastic two-level linear programming problems. Using the concept of chance constraints and probability maximization, original problems are transformed into deterministic ones. An interactive fuzzy programming method is presented for deriving a satisfactory solution efficiently with considerations of overall satisfactory balance.
A general purpose, modular computational platform for fluid-structure interaction problems
A general purpose fluid-structure interaction (FSI) methodology is currently under development with the capability of simulating several problems of interest, from aeroelasticity problems to sub-sea propulsion using shape deformation. This paper will describe a modular FSI code and present results for a few test cases that were used to validate the code. (author)
Solution to sign problems in models of interacting fermions and quantum spins
Huffman, Emilie
2016-01-01
We show that solutions to fermion sign problems in the CT-INT formulation can be extended to systems involving fermions interacting with dynamical quantum spins. While these sign problems seem unsolvable in the auxiliary field approach, solutions emerge in the worldline representation of quantum spins. Combining the idea with meron-cluster methods, we are able to extend the solvable models even further. We demonstrate these novel solutions to sign problems by considering several examples of strongly correlated systems.
SPH Simulation of Fluid-Structure Interaction Problems with Application to Hovercraft
Yang, Qing
2011-01-01
A Computational Fluid Dynamics (CFD) tool is developed in this thesis to solve complex fluid-structure interaction (FSI) problems. The fluid domain is based on Smoothed Particle Hydro-dynamics (SPH) and the structural domain employs large-deformation Finite Element Method (FEM). Validation tests of SPH and FEM are first performed individually. A loosely-coupled SPH-FEM model is then proposed for solving FSI problems. Validation results of two benchmark FSI problems are illustrated (Antoci et ...
Argeso, Hakan; Mengi, Yalcin
2014-02-01
A unified formulation is presented, based on the boundary element method, to perform the interaction analysis for the problems involving poroviscoelastic media. The proposed formulation permits the evaluation of all the elements of impedance and input motion matrices at a single step in terms of system matrices of boundary element method without solving any special problem, such as, unit displacement or load problem, as required by conventional methods. It further eliminates the complicated procedure and the need for using scattering analysis in the evaluation of input motion functions. The formulation is explained by considering a simple interaction problem involving an inclusion embedded in an infinite poroviscoelastic medium, which is under the influence of a dynamic excitation induced by seismic waves. In the formulation, an impedance relation is established for this interaction problem, suitable for performing the interaction analysis by substructure method, which permits carrying out the analysis for inclusion and its surrounding medium separately. The inclusion is first treated as poroviscoelastic, then viscoelastic and finally rigid, where the formulation in each of these cases is obtained consecutively as a special case of the previous one. It is remarkable to note that, a cavity problem where there is a hole in place of inclusion can be also considered within the framework of the present formulation. The formulation is assessed by applying it to some sample problems. The extension of the formulation to other types of interaction problems, such as, multi-inclusion problems, the analyses of foundations supported by a poroviscoelastic medium, etc., will be the subject of a separate study.
A Boundary Element Solution to the Problem of Interacting AC Fields in Parallel Conductors
Einar M. Rønquist
1984-04-01
Full Text Available The ac fields in electrically insulated conductors will interact through the surrounding electromagnetic fields. The pertinent field equations reduce to the Helmholtz equation inside each conductor (interior problem, and to the Laplace equation outside the conductors (exterior problem. These equations are transformed to integral equations, with the magnetic vector potential and its normal derivative on the boundaries as unknowns. The integral equations are then approximated by sets of algebraic equations. The interior problem involves only unknowns on the boundary of each conductor, while the exterior problem couples unknowns from several conductors. The interior and the exterior problem are coupled through the field continuity conditions. The full set of equations is solved by standard Gaussian elimination. We also show how the total current and the dissipated power within each conductor can be expressed as boundary integrals. Finally, computational results for a sample problem are compared with a finite difference solution.
Westlander, Meghan Joanne
Interactive engagement environments are critical to students' conceptual learning gains, and often the instructor is ultimately responsible for the creation of that environment in the classroom. When those instructors are graduate teaching assistants (GTAs), one of the primary ways in which they can promote interactive engagement is through their interactions with students. Much of the prior research on physics GTA-student interactions focuses on GTA training programs (e.g. Ezrailson (2004); Smith, Ward, and Rosenshein (1977)) or on GTAs' specific actions and beliefs (e.g. West, Paul, Webb, and Potter (2013); Goertzen (2010); Spike and Finkelstein (2012a)). Research on students' ideas and behaviors within and surrounding those interactions is limited but important to obtaining a more complete understanding of how GTAs promote an interactive environment. In order to begin understanding this area, I developed the Issues Framework to examine how GTA-student interactions are situated in students' processes during physics problem solving activities. Using grounded theory, the Issues Framework emerged from an analysis of the relationships between GTA-student interactions and the students procedures and expressions of physics content in and surrounding those interactions. This study is focused on introducing the Issues Framework and the insight it can provide into GTA-student interactions and students' processes. The framework is general in nature and has a visually friendly design making it a useful tool for consolidating complex data and quickly pattern-matching important pieces of a complex process. Four different categories of Issues emerged spanning the problem solving process: (1) Getting Started, (2) Solution Approach, (3) Unit Conversions, and (4) Other. The framework allowed for identification of the specific contents of the Issues in each category as well as revealing the common stories of students' processes and how the interactions were situated in those
Analysis of the Many-Body Problem in One Dimension with Repulsive Delta-Function Interaction
Albertsson, Martin
2014-01-01
The repulsive delta-function interaction model in one dimension is reviewed for spinless particles and for spin-1/2 fermions. The problem of solving the differential equation related to the Schrödinger equation is reduced by the Bethe ansatz to a system of algebraic equations. The delta-function interaction is shown to have no effect on spinless fermions which therefore behave like free fermions, in agreement with Pauli's exclusion principle. The ground-state problem of spinless bosons is red...
Comparison of shape parametrization techniques for fluid-structure interaction problems
Forti, Davide
2012-01-01
This master thesis describes the development in the framework of Fluid- Structure Interaction (FSI) problems of an efficient and flexible technique treating the fluid-structure interface and mesh motion problems. The main idea is to build, through a new hierarchical approach, a tool with accurate identication capabilities for both the structural rigid movement (translation/rotation) and the elastic deformation (displacement), with the possibility of facing arbitrary structural and fluid discr...
A Modular, Operator Splitting Scheme for Fluid-Structure Interaction Problems with Thick Structures
Bukac, Martina; Canic, Suncica; Glowinski, Roland; Muha, Boris; Quaini, Annalisa
2013-01-01
We present an operator-splitting scheme for fluid-structure interaction (FSI) problems in hemodynamics, where the thickness of the structural wall is comparable to the radius of the cylindrical fluid domain. The equations of linear elasticity are used to model the structure, while the Navier-Stokes equations for an incompressible viscous fluid are used to model the fluid. The operator splitting scheme, based on Lie splitting, separates the elastodynamics structure problem, from a fluid proble...
Background: In recent years some reactors have experienced significant steam dryer cracking. In some cases, this cracking has necessitated unplanned outages to implement steam dryer repairs and has also resulted in de-rated operation of the affected units. Initial inspection showed it was likely that steam dryer had been damaged by high cycle fatigue due to flow-induced acoustic resonance in the main steam lines. Because of the complexity and acoustic-structure coupling effect, scale model test is adopted to research the mechanism of acoustic fatigue. Purpose: This paper describes the derivations of scaling laws observed to control the system response for phenomena considered to be significant in the real plants. Methods: Basic governing equations of elasticity and acoustics are written in non-dimensional form, non-dimensional groups are defined and derived. Results: Using the reference values in the real plants, the scaling laws and scaling relationships are derived and recognized to enable conversion of model data into real plant predictions. Conclusions: Successful model testing can be achieved if these significant parameters are preserved in the model scale. (author)
Singh, Chandralekha
2016-01-01
We discuss the development of interactive video tutorial-based problems to help introductory physics students learn effective problem solving heuristics. The video tutorials present problem solving strategies using concrete examples in an interactive environment. They force students to follow a systematic approach to problem solving and students are required to solve sub-problems (research-guided multiple choice questions) to show their level of understanding at every stage of prob lem solvin...
A. S. Koval
2010-01-01
Full Text Available The paper considers problems concerning electromechanical interaction in elevators with an adjustable asynchronous electric drive equipped with the vector control systems under direct torque control and direct torque control with pulse-width modulator. A mathematical description of electromechanical elevator system with due account of nonlinearity of the worm gear is given in the paper. The paper presents a simplified circuit design of a control system with a fuzzy speed controller. It has been established that the factor of electromechanical interaction in electromechanical system with the adjustable asynchronous electric drive and an fuzzy speed controller is within the range which corresponds to existence of the essential electromechanical interaction.
Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny
2009-01-01
n interactive physical simulation, contact forces are applied to prevent rigid bodies from penetrating each other. Accurate contact force determination is a computationally hard problem. Thus, in practice one trades accuracy for performance. The result is visual artifacts such as viscous or damped...
EZLP: An Interactive Computer Program for Solving Linear Programming Problems. Final Report.
Jarvis, John J.; And Others
Designed for student use in solving linear programming problems, the interactive computer program described (EZLP) permits the student to input the linear programming model in exactly the same manner in which it would be written on paper. This report includes a brief review of the development of EZLP; narrative descriptions of program features,…
Karreman, Annemiek; van Tuijl, Cathy; van Aken, Marcel A. G.; Dekovi, Maja
2009-01-01
This study investigated interactions between observed temperamental effortful control and observed parenting in the prediction of externalizing problems. Child gender effects on these relations were examined. The relations were examined concurrently when the child was 3 years old and longitudinally at 4.5 years. The sample included 89 two-parent…
Radiation interaction with substance and simulation of the nuclear geophysical problems
Main processes of interaction of various types of nuclear radiation (NR) with substance, NR transport theory and physical- mathematical simulation of basic problems of nuclear geophysics (NG) are considered. General classification of NG methods according to the type of the detected radiation with a more detailed division according to the physical essence of the interaction process employed is given. Direct NG problems are related to the study of space- energy radiation distribution in substance under certain cross sections of elementary interaction processes, substance properties and specified geometric conditions. The theoretical solution of the direct problems is based on using mathematical models of radiation transport in specified media. The NG inverse problems consist in determining element composition and other medium properties by data of integral or spectral characteristics of NR fields measurements. The NR in the course of its transport in substance can experience dozens of elementary interaction processes, the predominance of this or that process depending on NR energy, medium properties and geometric measurement conditions. This explains a wide NG method diversity. The Monte Carlo method application in the NR transport theory and various methods of decreasing calculations labour input are considered
Gavrilushkina O.P.
2012-09-01
Full Text Available The article presents the review of foreign and national investigations concerning genesis and specificity of interactions in children with difficulties in social contacts at early stages of ontogenesis. The following aspects of the problem were regarded: specificity of social interaction in children with autism spectrum disorder and mental retardation; peculiarities of child social interaction as depending on ethnic and gender attributes; factors determining the quality of interaction and social interaction in various age groups; the role of early support in normalizing the further child development; positive dynamics of interaction in conditions of inclusive education and so on.The reviewed studies stress the most significant reasons for low level of social interaction: decrease in need for social interaction, isolation (deprivation, lack of socio-communicative skills, difficulties in utilizing symbolic means, unfavorable situation of development, etc. It is shown that in case of specially structured educational environment it is possible to achieve positive dynamics in development of social and communicative competences in children with difficulties in social interaction.
Solution of large unsymmetric Eigen-systems for fluid-structure interaction problems
The finite element solution of fluid-structure interaction problems is considered for a class of acousto-elastic problems where the fluid is linear acoustic and the structure is linear elastic. The finite element formulation in terms of fluid pressure and structural displacement results in a system of unsymmetric equations. Due to the complexities of eigen-solution for large systems involving unsymmetric matrices, little progress has been reported. Recently, Yu showed that the real form of QZ-algorithm can be used for solving small unsymmetric eigen-problems of fluid-structure interaction, and as a major advance, this paper presents the use of the subspace iteration method, in conjunction with the QZ-algorithm, for solving large fluid-structure systems. The computational procedure is similar to that for the real symmetric case, and the procedure can easily be adopted by any finite element code
A semi-implicit level set method for multiphase flows and fluid-structure interaction problems
Cottet, Georges-Henri; Maitre, Emmanuel
2016-06-01
In this paper we present a novel semi-implicit time-discretization of the level set method introduced in [8] for fluid-structure interaction problems. The idea stems from a linear stability analysis derived on a simplified one-dimensional problem. The semi-implicit scheme relies on a simple filter operating as a pre-processing on the level set function. It applies to multiphase flows driven by surface tension as well as to fluid-structure interaction problems. The semi-implicit scheme avoids the stability constraints that explicit scheme need to satisfy and reduces significantly the computational cost. It is validated through comparisons with the original explicit scheme and refinement studies on two-dimensional benchmarks.
Reformulation of the covering and quantizer problems as ground states of interacting particles
Torquato, S.
2010-11-01
It is known that the sphere-packing problem and the number-variance problem (closely related to an optimization problem in number theory) can be posed as energy minimizations associated with an infinite number of point particles in d -dimensional Euclidean space Rd interacting via certain repulsive pair potentials. We reformulate the covering and quantizer problems as the determination of the ground states of interacting particles in Rd that generally involve single-body, two-body, three-body, and higher-body interactions. This is done by linking the covering and quantizer problems to certain optimization problems involving the “void” nearest-neighbor functions that arise in the theory of random media and statistical mechanics. These reformulations, which again exemplify the deep interplay between geometry and physics, allow one now to employ theoretical and numerical optimization techniques to analyze and solve these energy minimization problems. The covering and quantizer problems have relevance in numerous applications, including wireless communication network layouts, the search of high-dimensional data parameter spaces, stereotactic radiation therapy, data compression, digital communications, meshing of space for numerical analysis, and coding and cryptography, among other examples. In the first three space dimensions, the best known solutions of the sphere-packing and number-variance problems (or their “dual” solutions) are directly related to those of the covering and quantizer problems, but such relationships may or may not exist for d≥4 , depending on the peculiarities of the dimensions involved. Our reformulation sheds light on the reasons for these similarities and differences. We also show that disordered saturated sphere packings provide relatively thin (economical) coverings and may yield thinner coverings than the best known lattice coverings in sufficiently large dimensions. In the case of the quantizer problem, we derive improved upper
A framework for the interactive resolution of multi-objective vehicle routing problems
Geiger, Martin Josef
2008-01-01
The article presents a framework for the resolution of rich vehicle routing problems which are difficult to address with standard optimization techniques. We use local search on the basis on variable neighborhood search for the construction of the solutions, but embed the techniques in a flexible framework that allows the consideration of complex side constraints of the problem such as time windows, multiple depots, heterogeneous fleets, and, in particular, multiple optimization criteria. In order to identify a compromise alternative that meets the requirements of the decision maker, an interactive procedure is integrated in the resolution of the problem, allowing the modification of the preference information articulated by the decision maker. The framework is prototypically implemented in a computer system. First results of test runs on multiple depot vehicle routing problems with time windows are reported.
Ceberio, Mikel; Almudí, José Manuel; Franco, Ángel
2016-03-01
In recent years, interactive computer simulations have been progressively integrated in the teaching of the sciences and have contributed significant improvements in the teaching-learning process. Practicing problem-solving is a key factor in science and engineering education. The aim of this study was to design simulation-based problem-solving teaching materials and assess their effectiveness in improving students' ability to solve problems in university-level physics. Firstly, we analyze the effect of using simulation-based materials in the development of students' skills in employing procedures that are typically used in the scientific method of problem-solving. We found that a significant percentage of the experimental students used expert-type scientific procedures such as qualitative analysis of the problem, making hypotheses, and analysis of results. At the end of the course, only a minority of the students persisted with habits based solely on mathematical equations. Secondly, we compare the effectiveness in terms of problem-solving of the experimental group students with the students who are taught conventionally. We found that the implementation of the problem-solving strategy improved experimental students' results regarding obtaining a correct solution from the academic point of view, in standard textbook problems. Thirdly, we explore students' satisfaction with simulation-based problem-solving teaching materials and we found that the majority appear to be satisfied with the methodology proposed and took on a favorable attitude to learning problem-solving. The research was carried out among first-year Engineering Degree students.
Ceberio, Mikel; Almudí, José Manuel; Franco, Ángel
2016-08-01
In recent years, interactive computer simulations have been progressively integrated in the teaching of the sciences and have contributed significant improvements in the teaching-learning process. Practicing problem-solving is a key factor in science and engineering education. The aim of this study was to design simulation-based problem-solving teaching materials and assess their effectiveness in improving students' ability to solve problems in university-level physics. Firstly, we analyze the effect of using simulation-based materials in the development of students' skills in employing procedures that are typically used in the scientific method of problem-solving. We found that a significant percentage of the experimental students used expert-type scientific procedures such as qualitative analysis of the problem, making hypotheses, and analysis of results. At the end of the course, only a minority of the students persisted with habits based solely on mathematical equations. Secondly, we compare the effectiveness in terms of problem-solving of the experimental group students with the students who are taught conventionally. We found that the implementation of the problem-solving strategy improved experimental students' results regarding obtaining a correct solution from the academic point of view, in standard textbook problems. Thirdly, we explore students' satisfaction with simulation-based problem-solving teaching materials and we found that the majority appear to be satisfied with the methodology proposed and took on a favorable attitude to learning problem-solving. The research was carried out among first-year Engineering Degree students.
Ana-Raluca Chiriac
2006-01-01
Full Text Available Between structure, infrastructure (foundation and soil there is an effective interaction, which has to be taken into account as correctly as possible every time we do the calculation. This effective interaction can be analysed in a global form, considering on one hand the entire building, and on the other hand the soil -- establishment surface, or in an analytical form: we consider first the soil -- infrastructure (foundation interaction and then the structure -- infrastructure one. Without considering the interaction, we cannot make neither the calculation (for the soil according to the limiting deformation state which has to be compatible with the structure’s resistance system, nor calculation for the limiting resistance state, because the correct distribution of efforts along the contact surface between the soil and the structure is unknown, so we cannot determine the zones of plastical equilibrium in the soil massive and the conditions of limited equilibrium. Also, without considering the infrastructure, we cannot correctly calculate the efforts and the deformations which may occur in all resistance elements of the building. Therefore, we cannot talk about limiting state calculation without considering the interaction between the soil and the structure itself. The problem of interaction between building, on one hand and soil foundation, on the other hand, is not approached very much in the specialized literature, because of the big difficulties raised by summarizing all the factors that describe the structure and the environment, which would be more accessible to a practical calculation. A lot of buildings or elements of buildings standing on the soil or on another environment with finite rigidity can be taken into account as beams supported on a straining environment, (continuous foundations, resistance walls, longitudinal and transversal membranes of civil and industrial buildings, hydrotechnic works. Therefore, in the present paper we
Zhang, Hao; Trias, F Xavier; Yu, Aibing; Tan, Yuanqiang; Oliva, Assensi
2015-01-01
In our recent work [H. Zhang, F.X. Trias, A. Oliva, D. Yang, Y. Tan, Y. Sheng. PIBM: Particulate immersed boundary method for fluid-particle interaction problems. Powder Technology. 272(2015), 1-13.], a particulate immersed boundary method (PIBM) for simulating fluid-particle multiphase flow was proposed and assessed in both two- and three-dimensional applications. In this study, the PIBM was extended to solve thermal interaction problems between spherical particles and fluid. The Lattice Boltzmann Method (LBM) was adopted to solve the fluid flow and temperature fields, the PIBM was responsible for the non-slip velocity and temperature boundary conditions at the particle surface, and the kinematics and trajectory of the solid particles were evaluated by the Discrete Element Method (DEM). Four case studies were implemented to demonstrate the capability of the current coupling scheme. Firstly, numerical simulation of natural convection in a two-dimensional square cavity with an isothermal concentric annulus was...
Solving the Milky Way Satellite Problem with Interactions between Cold Dark Matter and Radiation
Boehm, C; Wilkinson, R J; Baugh, C M; Pascoli, S
2014-01-01
The cold dark matter (CDM) model faces persistent challenges on small scales. In particular, the model significantly overestimates the number of satellite galaxies around the Milky Way. Attempts to solve this problem remain controversial and have even led some to abandon CDM altogether. However, current simulations are limited by the assumption that dark matter feels only gravity. Here we show that including interactions between CDM and radiation (photons or neutrinos) leads to a dramatic reduction in the number of satellite galaxies, providing a potential solution to the Milky Way satellite problem and indicating that physics beyond gravity may be essential to make accurate predictions of structure formation on small scales. The methodology introduced here gives constraints on dark matter interactions that are significantly improved over those from the cosmic microwave background.
Interactive Fuzzy Goal Programming approach for Tri-Level Linear Programming Problems
Dr. Taghreed A. Hassan
2014-11-01
Full Text Available The aim of this paper is to present an interactive fuzzy goal programming approach to determine the preferred compromise solution to Tri-level linear programming problems considering the imprecise nature of the decision makers’ judgments for the objectives. Using the concept of goal programming, fuzzy set theory, in combination with interactive programming, and improving the membership functions by means of changing the tolerances of the objectives provide a satisfactory compromise (near to ideal solution to the upper level decision makers. Two numerical examples for three-level linear programming problems have been solved to demonstrate the feasibility of the proposed approach. The performance of the proposed approach was evaluated by using of metric distance functions with other approaches.
Discrete and continuum links to a nonlinear coupled transport problem of interacting populations
Duong, Manh Hong; Muntean, Adrian; Richardson, Omar
2016-01-01
We are interested in exploring interacting particle systems that can be seen as microscopic models for a particular structure of coupled transport flux arising when different populations are jointly evolving. The scenarios we have in mind are inspired by the dynamics of pedestrian flows in open spaces and are intimately connected to cross-diffusion and thermo-diffusion problems holding a variational structure. The tools we use include a suitable structure of the relative entropy controlling T...
Muhtadie, Luma; Zhou, Qing; Eisenberg, Nancy; Wang, Yun
2013-01-01
The additive and interactive relations of parenting styles (authoritative and authoritarian parenting) and child temperament (anger/frustration, sadness, and effortful control) to children’s internalizing problems were examined in a 3.8-year longitudinal study of 425 Chinese children (6 – 9 years) from Beijing. At Wave 1, parents self-reported on their parenting styles, and parents and teachers rated child temperament. At Wave 2, parents, teachers, and children rated children’s internalizing ...
TPLOT: An interactive data management system for transient problems 3. Edition
This report describes the use of an interactive data management system suitable for post-processing of transient structural problems. The system is designed for IBM compatible environment (TSO command procedures) and makes use of PLOT-10 (TEKTRONIX) for graphical output (time plots). Interfaces are provided for experimental data and for various programs used in fast reactor safety analysis (EURDYN, SEURBNUK, ASTARTE, FRAP-T5, RODSWELL, SIMMER, TRACRUF, PHEAT, JOULE). Some examples are given to illustrate the system
Interaction between Dark Matter and Dark Energy and the Cosmological Coincidence Problem
Kourosh Nozari; Noushin Behrouz; Narges Rashidi
2014-01-01
We consider a quintessence model of dark energy inspired by scalar-tensor theories of gravity where the scalar field is nonminimally coupled to gravity and dark matter. By considering exponential potential as self-interaction potential, the stability and existence of the critical points are discussed in details. With nonminimally coupled dark sector with gravity, we obtain scaling solutions to address the coincidence problem by considering complex velocity for dark matter. The statefinder dia...
A. S. Koval; A. V. Shvayakou
2014-01-01
The paper considers problems concerning electromechanical interaction in elevators with an adjustable asynchronous electric drive equipped with the vector control systems under direct torque control and direct torque control with pulse-width modulator. A mathematical description of electromechanical elevator system with due account of nonlinearity of the worm gear is given in the paper. The paper presents a simplified circuit design of a control system with a fuzzy speed controller. It has be...
Nobile, Fabio; Pozzoli, Matteo; Vergara, Christian
2014-01-01
In this paper we consider the numerical solution of the three-dimensional fluid–structure interaction problem in haemodynamics, in the case of real geometries, physiological data and finite elasticity vessel deformations. We study some new inexact schemes, obtained from semi-implicit approximations, which treat exactly the physical interface conditions while performing just one or few iterations for the management of the interface position and of the fluid and structure non-linearities. We sh...
Exactly solvable models : a solution to different problems of laser matter interaction
Petite, Guillaume; Shvartsburg, Alexander
2004-01-01
With the increasing use of ultrashort laser pulses and nanoscale-materials, one is regularly confronted to situations in which the properties of the media supporting propagation are not varying slowly with time (or space). Hence, the usual WKB-type approximations fail, and one has to resort to numerical treatments of the problems, with a considerable loss in our insight into the physics of laser-matter interaction. We will present a new approach which allows a fully analytical solution of suc...
ABOUT THE PROBLEMS OF THE RESEARCH OF ORGANISMS INTERACTION WITH THE MICROWAVE RADIATION
DAROVSKIH S.N.; SHISHKOVA YU.S.; VDOVINA N.V.; VODYANITSKIY E.V.
2016-01-01
The analysis of the main problems of studies of the organisms interaction with electromagnetic radiation in the microwave range is submitted. The controversial approach to assessing the role of microwave radiations of artificial origin for organisms is noted. One group of scientists considers these radiations as potentially dangerous to an organism, and the other group claims that under certain conditions they can be used in the medical purposes. The specified contradiction is eliminated by u...
Fairbairn, Catharine E; Cranford, James A
2016-08-01
Models of alcohol use disorder (AUD) are increasingly conceptualizing social and relationship factors as being critical to the understanding of problem drinking. Close relationships involving conflict have been a particular research focus, and partners' expressions of negative emotion are theorized to affect drinking among those with AUD. Although it has long been presumed that behaviors during couples interactions influence drinking-and this assumption has informed many modern treatments for AUD-this hypothesis has not been directly tested. We bring multiple methods to bear on this question, combining laboratory-based behavioral observation with a longitudinal design. Forty-eight individuals with AUD (probands), together with their partners, completed a laboratory-based conflict interaction. Their behavior was coded with the Rapid Marital Interaction Coding System. Longitudinal follow-ups of drinking behaviors were completed at 6 and 12 months. Results showed that, above and beyond the proband's own behaviors, partner negative behaviors moderated probands' drinking trajectories, with drinkers whose partners displayed higher levels of hostility at baseline reporting slower declines in frequency of drinking, heavy episodic drinking, and alcohol problems over time and higher levels of drinking, heavy episodic drinking, and alcohol problems at follow-up. Results emphasize the importance of considering close relationships in the study of AUD and further indicate the utility of combining multiple methods in alcohol research. (PsycINFO Database Record PMID:27362489
Wang Yong
2011-10-01
Full Text Available Abstract Background With the development of genome-sequencing technologies, protein sequences are readily obtained by translating the measured mRNAs. Therefore predicting protein-protein interactions from the sequences is of great demand. The reason lies in the fact that identifying protein-protein interactions is becoming a bottleneck for eventually understanding the functions of proteins, especially for those organisms barely characterized. Although a few methods have been proposed, the converse problem, if the features used extract sufficient and unbiased information from protein sequences, is almost untouched. Results In this study, we interrogate this problem theoretically by an optimization scheme. Motivated by the theoretical investigation, we find novel encoding methods for both protein sequences and protein pairs. Our new methods exploit sufficiently the information of protein sequences and reduce artificial bias and computational cost. Thus, it significantly outperforms the available methods regarding sensitivity, specificity, precision, and recall with cross-validation evaluation and reaches ~80% and ~90% accuracy in Escherichia coli and Saccharomyces cerevisiae respectively. Our findings here hold important implication for other sequence-based prediction tasks because representation of biological sequence is always the first step in computational biology. Conclusions By considering the converse problem, we propose new representation methods for both protein sequences and protein pairs. The results show that our method significantly improves the accuracy of protein-protein interaction predictions.
Interactions between discontinuities for binary mixture separation problem and hodograph method
Elaeva, M S; Yu, Zhukov M
2016-01-01
The Cauchy problem for first-order PDE with the initial data which have a piecewise discontinuities localized in different spatial points is completely solved. The interactions between discontinuities arising after breakup of initial discontinuities are studied with the help of the hodograph method. The solution is constructed in analytical implicit form. To recovery the explicit form of solution we propose the transformation of the PDEs into some ODEs on the level lines (isochrones) of implicit solution. In particular, this method allows us to solve the Goursat problem with initial data on characteristics. The paper describes a specific problem for zone electrophoresis (method of the mixture separation). However, the method proposed allows to solve any system of two first-order quasilinear PDEs for which the second order linear PDE, arising after the hodograph transformation, has the Riemann-Green function in explicit form.
Muhtadie, Luma; Zhou, Qing; Eisenberg, Nancy; Wang, Yun
2013-08-01
The additive and interactive relations of parenting styles (authoritative and authoritarian parenting) and child temperament (anger/frustration, sadness, and effortful control) to children's internalizing problems were examined in a 3.8-year longitudinal study of 425 Chinese children (aged 6-9 years) from Beijing. At Wave 1, parents self-reported on their parenting styles, and parents and teachers rated child temperament. At Wave 2, parents, teachers, and children rated children's internalizing problems. Structural equation modeling indicated that the main effect of authoritative parenting and the interactions of Authoritarian Parenting × Effortful Control and Authoritative Parenting × Anger/Frustration (parents' reports only) prospectively and uniquely predicted internalizing problems. The above results did not vary by child sex and remained significant after controlling for co-occurring externalizing problems. These findings suggest that (a) children with low effortful control may be particularly susceptible to the adverse effect of authoritarian parenting and (b) the benefit of authoritative parenting may be especially important for children with high anger/frustration. PMID:23880383
The significance of the evanescent spectrum in structure-waveguide interaction problems.
Tsouvalas, Apostolos; van Dalen, Karel N; Metrikine, Andrei V
2015-10-01
Modal decomposition is often applied in elastodynamics and acoustics for the solution of problems related to propagation of mechanical disturbances in waveguides. One of the key elements of this method is the solution of an eigenvalue problem for obtaining the roots of the dispersion equation, which signify the wavenumbers of the waves that may exist in the system. For non-dissipative media, the wavenumber spectrum consists of a finite number of real roots supplemented by infinitely many imaginary and complex ones. The former refer to the propagating modes in the medium, whereas the latter constitute the so-called evanescent spectrum. This study investigates the significance of the evanescent spectrum in structure-waveguide interaction problems. Two cases are analysed, namely, a beam in contact with a fluid layer and a cylindrical shell interacting with an acousto-elastic waveguide. The first case allows the introduction of a modal decomposition method and the establishment of appropriate criteria for the truncation of the modal expansions in a simple mathematical framework. The second case describes structure-borne wave radiation in an offshore environment during the installation of a pile with an impact hammer-a problem that has raised serious concerns in recent years due to the associated underwater noise pollution. PMID:26520340
Study on the key problems of interaction between microwave and chemical reaction
YANG Xiaoqing; HUANG Kama
2007-01-01
Microwave has been found as an efficient heating method in chemical industry.However,in present days the interaction between microwave and chemical reactions has not been deeply understood,which restricts a wider application of high power microwave in chemical industry.In this Paper,the key problems of interaction between microwave and chemical reaction are investigated,such as complex effective permittivity of chemical reaction,simulation of microwave heating on chemical reaction and non-thermal effect of microwave,which will enhance further knowledge of the mechanism of interaction between microwave and chemical reaction.Moreover,such an analysis is beneficial for handling with difficulties in application of microwave chemical industry.
Prinsloo, Belinda
2014-01-01
Educators experience numerous daily challenges in the classroom, including learner problem behaviour. Within the classroom, problem behaviour is defined as any behaviour that interferes in the flow of the lesson. How educators experience problem behaviour, and how they manage interactions with learners who display problem behaviour in the classroom, impact on both educator and learner functioning. Difficulties in managing learner problem behaviour are viewed as a contributing cause of educato...
Hidekatsu Kuroda; Keisuke Kakisaka; Naohisa Kamiyama; Takayoshi Oikawa; Mio Onodera; Kei Sawara; Kanta Oikawa
2012-01-01
AIM:To use leptin-deficient (ob/ob) mice with demonstrated differences in steatosis levels to test a new diagnostic method using the acoustical structure quantification (ASQ) mode and the associated analytical parameter,"focal disturbance ratio" (FD-ratio).METHODS:Nine ob/ob mice,at 5,8,and 12 wk of age (n =3 in each age group),were used as models for hepatic steatosis.Echo signals obtained from ultrasonography in the mice were analyzed by ASQ,which uses a statistical analysis of echo amplitude to estimate inhomogeneity in the diagnostic region.FD-ratio,as calculated from this analysis,was the focus of the present study.FD-ratio and fat droplet areas and sizes were compared between age groups.RESULTS:No fibrosis or inflammation was observed in any of the groups.The fat droplet area significantly (P ＜ 0.01) increased with age from 1.25％ ± 0.28％ at 5 wk to 31.07％ ± 0.48％ at 8 wk to 51.69％ ± 3.19％at 12 wk.The median fat droplet size also significantly (P ＜ 0.01) increased with age,from 1.33 (0.55-10.52)μm at 5 wk,2.82 (0.61-44.13) μm at 8 wk and 6.34(0.66-81.83) μm at 12 wk.The mean FD-ratio was 0.42± 0.11 at 5 wk,0.11 ± 0.05 at 8 wk,and 0.03 ± 0.02at 12 wk.The FD-ratio was significantly lower at 12 wk than at 5 wk and 8 wk (P ＜ 0.01).A significant negative correlation was observed between the FD-ratio and either the fat droplet area (r =-0.7211,P =0.0017) or fat droplet size (r =-0.9811,P =0.0052).CONCLUSION:This tool for statistical analysis of signals from ultrasonography using the FD-ratio can be used to accurately quantify fat in vivo in an animal model of hepatic steatosis,and may serve as a quantitative biomarker of hepatic steatosis.
Singh, Chandralekha
2016-01-01
We discuss the development of interactive video tutorial-based problems to help introductory physics students learn effective problem solving heuristics. The video tutorials present problem solving strategies using concrete examples in an interactive environment. They force students to follow a systematic approach to problem solving and students are required to solve sub-problems (research-guided multiple choice questions) to show their level of understanding at every stage of prob lem solving. The tutorials are designed to provide scaffolding support at every stage of problem solving as needed and help students view the problem solving process as an opportunity for knowledge and skill acquisition rather than a "plug and chug" chore. A focus on helping students learn first to analyse a problem qualitatively, and then to plan a solution in terms of the relevant physics principles, can be useful for developing their reasoning skills. The reflection stage of problem solving can help students develop meta-cogniti...
Interactions of relativistic heavy ions in thick heavy element targets and some unresolved problems
Interactions of relativistic heavy ions with total energies above 30 GeV in thick Cu and Pb targets (≥2 cm) have been studied with various techniques. Radiochemical irradiation experiments using thick Cu targets, both in a compact form or as diluted '2π-Cu targets' have been carried out with several relativistic heavy ions, such as 44 GeV 12C (JINR, Dubna) and 72 GeV 40Ar (LBL, Berkeley, USA). Neutron measuring experiments using thick targets irradiated with various relativistic heavy ions up to 44 GeV 12C have been performed at JINR. In addition, the number of 'black prongs' in nuclear interactions (due to protons with energies less than 30 MeV and emitted from the target-like interaction partner at rest) produced with 72 GeV 22Ne ions in nuclear emulsion plates has been measured in the first nuclear interaction of the primary 22Ne ion and in the following second nuclear interaction of the secondary heavy (Z>1) ion. Some essential results have been obtained. 1) Spallation products produced by relativistic secondary fragments in interactions ([44 GeV 12C or 72 GeV 40Ar]+Cu) within thick copper yield less products close to the target and much more products far away from the target as compared to primary beam interactions. This applies also to secondary particles emitted into large angles (Θ>10deg). 2) The neutron production of 44 GeV 12C within thick Cu and Pb targets is beyond the estimated yield as based on experiments with 12 GeV 12C. These rather independent experimental results cannot be understood with well-accepted nuclear reaction models. They appear to present unresolved problems
Gainsbury, Sally M; Russell, Alex; Hing, Nerilee; Wood, Robert; Lubman, Dan I; Blaszczynski, Alex
2014-09-01
New technology is changing the nature of gambling with interactive modes of gambling becoming putatively associated with higher rates of problem gambling. This paper presents the first nationally representative data on the prevalence and correlates of problem gambling among Australian adults since 1999 and focuses on the impact of interactive gambling. A telephone survey of 15,006 adults was conducted. Of these, 2,010 gamblers (all interactive gamblers and a randomly selected subsample of those reporting land-based gambling in the past 12 months) also completed more detailed measures of problem gambling, substance use, psychological distress, and help-seeking. Problem gambling rates among interactive gamblers were 3 times higher than for noninteractive gamblers. However, problem and moderate risk gamblers were most likely to attribute problems to electronic gaming machines and land-based gambling, suggesting that although interactive forms of gambling are associated with substantial problems, interactive gamblers experience significant harms from land-based gambling. The findings demonstrate that problem gambling remains a significant public health issue that is changing in response to new technologies, and it is important to develop strategies that minimize harms among interactive gamblers. PMID:24865462
Efficient computational procedures for long-time duration fluidstructure interaction problems
In this paper, two different classes of transient algorithms, implicit-explicit and implicit-implicit, are developed for the response calculations of long-time duration fluid structure interaction problems which arise during a seismic event. To avoid the stringent time step, the generalized structural and fluid displacements are integrated implicitly. If the fluid wave effect is important (e.g., dam-reservoirs and fluid-pipe systems), the second-order accuracy explicit Rational Runge-Kutta (RRK) operator is employed to integrate the fluid pressure. If the fluid is incompressible or the fluid inertia is much greater than that due to the structure (e.g., fluid-tank systems and nuclear reactor systems), the implicit generalized trapezoidal family of methods are employed to integrate the fluid pressure. With the implicit-explicit partition, the advantage of employing larger time step is achieved; whereas with the implicit-implicit partition, unconditional stability is sought. The resulting coupled matrix equations are ''symmetric'' and ''profiled'', and there is only one structural response calculation per time step. The accuracy and stability of these two algorithms are studied via an elastic piston wave interaction problem. The economical advantages in both computations and computer storage are examined on the problem of a fluid-pipe system
Using Interactive Case Studies to Support Students Understandings of Local Environmental Problems
Z. Kostova
2012-12-01
Full Text Available The article presents designed and refined an interactive-enhanced curriculum module for 9th grade secondary school students in Bulgaria, based on environmental case studies. In the module activities students from two schools studied the local environments, performed observations and experiments, collected and analyzed data, prepared and presented posters and role plays, made connections between scientific processes and socio-scientific issues and drew conclusions about the global effects of locally created environmental problems. The students’ critical observations of the quality of their surroundings helped them to make a list of local environmental problems, to apply interactive strategies in studying them and to propose rational scientifically based solutions. In the study the attention was directed to the advantages and disadvantages of poster presentations and role playing and to the specific learning difficulties that students had to overcome. Students’ achievements from the two experimental schools were assessed independently in order to give us insights into the details of learning using different interactive strategies and into the acquired performance skills, dependant on students’ interests and personal abilities. The three versions of the module (traditional, dominated by teacher presentation; poster preparation and presentation in which students imitate scientific team research; and role playing in which students not only study the local environmental problems but assume social roles to cope with them demonstrate three levels of students learning independence. Specific assessment tests and check lists were developed for analyzing, evaluating and comparing students’ achievements in each version of the module and in each school. Ecological knowledge assessment tests were based on Bloom’s taxonomy of educational objectives. Poster and role playing preparations and presentations were assessed by specific criteria, shown in the
Gulland, E.-K.; Veenendaal, B.; Schut, A. G. T.
2012-07-01
Problem-solving knowledge and skills are an important attribute of spatial sciences graduates. The challenge of higher education is to build a teaching and learning environment that enables students to acquire these skills in relevant and authentic applications. This study investigates the effectiveness of traditional face-to-face teaching and online learning technologies in supporting the student learning of problem-solving and computer programming skills, techniques and solutions. The student cohort considered for this study involves students in the surveying as well as geographic information science (GISc) disciplines. Also, students studying across a range of learning modes including on-campus, distance and blended, are considered in this study. Student feedback and past studies reveal a lack of student interest and engagement in problem solving and computer programming. Many students do not see such skills as directly relevant and applicable to their perceptions of what future spatial careers hold. A range of teaching and learning methods for both face-to-face teaching and distance learning were introduced to address some of the perceived weaknesses of the learning environment. These included initiating greater student interaction in lectures, modifying assessments to provide greater feedback and student accountability, and the provision of more interactive and engaging online learning resources. The paper presents and evaluates the teaching methods used to support the student learning environment. Responses of students in relation to their learning experiences were collected via two anonymous, online surveys and these results were analysed with respect to student pass and retention rates. The study found a clear distinction between expectations and engagement of surveying students in comparison to GISc students. A further outcome revealed that students who were already engaged in their learning benefited the most from the interactive learning resources and
Adaptive solution of some steady-state fluid-structure interaction problems
This paper presents a general integrated and coupled formulation for modeling the steady-state interaction of a viscous incompressible flow with an elastic structure undergoing large displacements (geometric non-linearities). This constitutes an initial step towards developing a sensitivity analysis formulation for this class of problems. The formulation uses velocity and pressures as unknowns in a flow domain and displacements in the structural components. An interface formulation is presented that leads to clear and simple finite element implementation of the equilibrium conditions at the fluid-solid interface. Issues of error estimation and mesh adaptation are discussed. The adaptive formulation is verified on a problem with a closed form solution. It is then applied to a sample case for which the structure undergoes large displacements induced by the flow. (author)
Problems of Analyzing Consonant-tone Interaction in Thai: A Reply to Ruangjaroon
Tsung-Ying Chen
2007-12-01
Full Text Available The interaction between the distribution of tones and syllable types in Thai has been found to be interesting. The absence of the rising contour tone on CVO and CVVO supports the argument that syllables with shorter phonetic duration are bad licensers for the rising contour tone (Zhang 2002. The distributional gaps on CVO and CVVO are also found to be correlated with syllable-final glottalization (Moren & Zsiga 2006. Furthermore, Ruangjaroon (2006 argues that there is the consonant-tone interaction in Thai and analyzes it under the framework of OT. However, I will indicate both theoretical and analytical problems faced by analyses in Ruangjaroon (2006 in this paper.
A review of the plasma-material interaction problems for reacting and burning plasma experiments
Serious problems have to be faced at present in linking present plasma research to fusion reactor engineering. Even in fusion devices of the near-term and of the next generation which aim to evaluate the fusion engineering feasibility of burning plasma experiments such as TFTR, JET, R-tokamak, ZEPHYR and INTOR, plasma-material interactions cause many technological difficulties such as large heat loads, large erosion rates, large magnetic forces and large induced radioactivities. Moreover, impurity control, tritium handling, ash exhaust and refuelling need to be solved by realistic methods with technological justifications. Since present fusion approaches might not give hopeful predictions to an economical, safe, and reliable fusion reactor, it is most important at present to find a possible window of promising fusion research. In this paper, we review technological restrictions from viewpoints of plasma-material interactions, then discuss the fusion research and related material investigations that are necessary to realize reasonable fusion reactor concepts. (orig.)
Mei, Chuh; Pates, Carl S., III
1994-01-01
A coupled boundary element (BEM)-finite element (FEM) approach is presented to accurately model structure-acoustic interaction systems. The boundary element method is first applied to interior, two and three-dimensional acoustic domains with complex geometry configurations. Boundary element results are very accurate when compared with limited exact solutions. Structure-interaction problems are then analyzed with the coupled FEM-BEM method, where the finite element method models the structure and the boundary element method models the interior acoustic domain. The coupled analysis is compared with exact and experimental results for a simplistic model. Composite panels are analyzed and compared with isotropic results. The coupled method is then extended for random excitation. Random excitation results are compared with uncoupled results for isotropic and composite panels.
ALE Fractional Step Finite Element Method for Fluid-Structure Nonlinear Interaction Problem
无
2006-01-01
A computational procedure is developed to solve the problems of coupled motion of a structure and a viscous incompressible fluid. In order to incorporate the effect of the moving surface of the structure as well as the free surface motion, the arbitrary Lagrangian-Eulerian formulation is employed as the basis of the finite element spatial discretization. For numerical integration in time, the fraction step method is used. This method is useful because one can use the same linear interpolation function for both velocity and pressure. The method is applied to the nonlinear interaction of a structure and a tuned liquid damper. All computations are performed with a personal computer.
Innovative Interaction in Mixed Market: An Effect of Agency Problem in State-Owned Firm
Shinjiro Miyazawa
2008-01-01
I investigate an innovative interaction before a market competition in a mixed duopoly, where a state-owned firm and a private firm compete with each other. I find that although it reduces the effort level of the state-owned firm, an agency problem can improve the expected social welfare in some cases. I also find that setting the minimum wage level higher, which has an effect to lower the responsibility of bureaucratic managers, can be desirable from the viewpoint of expected social welfare ...
Problems with initial- and final-state interactions in deep-inelastic scattering
Although there exists a vast literature devoted to the theory of deep-inelastic scattering, the restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group and locality have not been considered. We argue that there is a problem with the current operator, leading to the standard parton-model results, satisfying these restrictions. At the same time, there exist models where the correct commutation relations and locality are satisfied but the initial- and final-state interactions of the struck quark with the remnants of the target cannot be neglected even in the Bjorken limit. (author)
Droplet Minimizers of an Isoperimetric Problem with long-range interactions
Cicalese, Marco
2011-01-01
We give a detailed description of the geometry of single droplet patterns in a nonlocal isoperimetric problem. In particular we focus on the sharp interface limit of the Ohta-Kawasaki free energy for diblock copolymers, regarded as a paradigm for those energies modeling physical systems characterized by a competition between short and a long-range interactions. Exploiting fine properties of the regularity theory for minimal surfaces, we extend previous partial results in different directions and give robust tools for the geometric analysis of more complex patterns.
Interaction between Dark Matter and Dark Energy and the Cosmological Coincidence Problem
Kourosh Nozari
2014-01-01
Full Text Available We consider a quintessence model of dark energy inspired by scalar-tensor theories of gravity where the scalar field is nonminimally coupled to gravity and dark matter. By considering exponential potential as self-interaction potential, the stability and existence of the critical points are discussed in details. With nonminimally coupled dark sector with gravity, we obtain scaling solutions to address the coincidence problem by considering complex velocity for dark matter. The statefinder diagnostic shows that the equation of state reaches ΛCDM model in the future.
Manuel Juárez Pacheco
2005-11-01
Full Text Available This study analyzes the practices of a group of high school science teachers in the development of a training seminar using the Computer-supported Collaborative Learning (CSCL approach. The pedagogical model, the tools used in collaboration, and the development of group dynamics are all described. The analysis is carried out using categories based on the concept of social infrastructure, which permits the identification of some of the skills required as well as problems that arose during the teachers’ synchronous and asynchronous interactions.
Lamont, L. A.; Chaar, L.; Toms, C.
2010-03-01
Interactive learning is beneficial to students in that it allows the continual development and testing of many skills. An interactive approach enables students to improve their technical capabilities, as well as developing both verbal and written communicative ability. Problem solving and communication skills are vital for engineering students; in the workplace they will be required to communicate with people of varying technical abilities and from different linguistic and engineering backgrounds. In this paper, a case study is presented that discusses how the traditional method of teaching control systems can be improved. 'Control systems' is a complex engineering topic requiring students to process an extended amount of mathematical formulae. MATLAB software, which enables students to interactively compare a range of possible combinations and analyse the optimal solution, is used to this end. It was found that students became more enthusiastic and interested when given ownership of their learning objectives. As well as improving the students' technical knowledge, other important engineering skills are also improved by introducing an interactive method of teaching.
Interacting dark energy models as an approach for solving Cosmic Coincidence Problem
Shojaei, Hamed
Understanding the dark side of the Universe is one of the main tasks of physicists. As there is no thorough understanding of nature of the dark energy, this area is full of new ideas and there may be several discoveries, theoretical or experimental, in the near future. We know that dark energy, though not detected directly, exists and it is not just an exotic idea. The presence of dark energy is required by the observation of the acceleration of the universe. There are several questions regarding dark energy. What is the nature of dark energy? How does it interact with matter, baryonic or dark? Why is the density of dark energy so tiny, i.e. why rhoΛ ≈ 10--120 M4Pl ? And finally why does its density have the same order of magnitude as the density of matter does at the present time? The last question is one form of what is known as the "Cosmic Coincidence Problem" and in this work, I have been investigating one way to resolve this issue. Observations of Type Ia supernovae indicate that we are in an accelerating universe. A matter-dominated universe cannot be accelerating. A good fit is obtained if we assume that energy density parameters are O Λ = 0.7 and Om = 0.3. Here O Λ is related to dark energy, or cosmological constant in ΛCDM model. At the same time data from Wilkinson Microwave Anisotropy Probe (WMAP) satellite and supernova surveys have placed a constraint on w, the equation of state for dark energy, which is actually the ratio of pressure and energy density. Any good theory needs to explain this coincidence problem and yields a value for w between -1.1 and -0.9. I have employed an interesting approach to solve this problem by assuming that there exists an interaction between dark energy and matter in the context of holographic dark energy. This interaction converts dark energy to matter or vice versa without violating the local conservation of energy in the universe. Holographic dark energy by itself indicates that the value of dark energy is related
Abrahamse Mariëlle E
2012-06-01
Full Text Available Abstract Background Persistent high levels of aggressive, oppositional and impulsive behaviours, in the early lives of children, are significant risk factors for adolescent and adult antisocial behaviour and criminal activity. If the disruptive behavioural problems of young children could be prevented or significantly reduced at an early age, the trajectory of these behavioural problems leading to adolescent delinquency and adult antisocial behaviour could be corrected. Parent–Child Interaction Therapy (PCIT is a short-term, evidence-based, training intervention for parents dealing with preschool children, who exhibit behavioural problems. Recently, PCIT was implemented in a Dutch community mental health setting. This present study aims to examine the short-term effects of PCIT on reducing the frequency of disruptive behaviour in young children. Methods This study is based on the data of 37 referred families. Whereby the results of which are derived from an analysis of parent reports of the Eyberg Child Behavior Inventory (ECBI, obtained during each therapeutic session. Furthermore, demographic information, extracted from client files, was also utilized. However, it must be noted that eleven families (27.5% dropped out of treatment before the treatment protocol was completed. To investigate the development of disruptive behaviour, a non-clinical comparison group was recruited from primary schools (N = 59. Results The results of this study indicate that PCIT significantly reduces disruptive behaviour in children. Large effect sizes were found for both fathers and mothers reported problems (d = 1.88, d = 1.99, respectively, which is similar to American outcome studies. At post treatment, no differences were found concerning the frequency of behavioural problems of children who completed treatment and those who participated in the non-clinical comparison group. Conclusion The findings of this study suggest that PCIT is potentially an
Li, Yun-He; Cui, Jing-Lei; Wang, Zhuo; Zhang, Xin
2010-01-01
Many dark energy models fail to pass the cosmic age test via the old quasar APM 08279+5255 at redshift $z=3.91$, even the $\\Lambda$CDM model and the holographic dark energy model are not exception. In this paper, we focus on the topic of age problem in the new agegraphic dark energy (NADE) model. We determine the age of the universe in the NADE model by using the fitting result of observational data including type Ia supernovae (SNIa), baryon acoustic oscillation (BAO) and cosmic microwave background (CMB). It is shown that the NADE model also faces the challenge of the age problem caused by the old quasar APM 08279+5255. In order to overcome such a difficulty, we consider the possible interaction between dark energy and matter. We show that the old quasar APM 08279+5255 at redshift $z=3.91$ can be successfully accommodated in the interacting new agegraphic dark energy (INADE) model at $2\\sigma$ level under the current observational constraints.
Nonlinear gauge interactions: a possible solution to the "measurement problem" in quantum mechanics
Hansson, Johan
2010-01-01
Two fundamental, and unsolved problems in physics are: i) the resolution of the "measurement problem" in quantum mechanics ii) the quantization of strongly nonlinear (nonabelian) gauge theories. The aim of this paper is to suggest that these two problems might be linked, and that a mutual, simultaneous solution to both might exist. We propose that the mechanism responsible for the "collapse of the wave function" in quantum mechanics is the nonlinearities already present in the theory via nonabelian gauge interactions. Unlike all other models of spontaneous collapse, our proposal is, to the best of our knowledge, the only one which does not introduce any new elements into the theory. A possible experimental test of the model would be to compare the coherence lengths - here defined as the distance over which quantum mechanical superposition is still valid - for, \\textit{e.g}, electrons and photons in a double-slit experiment. The electrons should have a finite coherence length, while photons should have a much ...
Lunkenheimer, Erika S.; Albrecht, Erin C.; Kemp, Christine J.
2013-01-01
Lower levels of parent-child affective flexibility indicate risk for children's problem outcomes. This short-term longitudinal study examined whether maternal depressive symptoms were related to lower levels of dyadic affective flexibility and positive affective content in mother-child problem-solving interactions at age 3.5?years…
Leckman-Westin, Emily; Cohen, Patricia R.; Stueve, Ann
2009-01-01
Objective: Increased behavior problems have been reported in offspring of mothers with depression. In-home observations link maternal depressive symptoms (MDS) and mother-child interaction patterns with toddler behavior problems and examine their persistence into late childhood. Method: Maternal characteristics (N = 153) and behaviors of…
Using interactive simulations to enhance conceptual development and problem solving skills
Van Heuvelen, Alan
1997-03-01
Research during recent decades indicates that traditional didactic instruction is not producing the student learning that we desire. More importantly, research is helping in the development of new pedagogical strategies and curriculum that are improving student achievement. We describe one effort based on this research. The goals are to help students develop qualitative representations and imagery so that they can reason effectively without math about physical processes; learn to use the symbolic language of physics by linking it to other representations such as words, sketches, diagrams, and graphs; develop the skills needed to solve complex multipart problems; learn to learn; and develop the skills needed to work effectively in groups. Interactive multimedia plays an important role in this learning system.
The Transitivity of Trust Problem in the Interaction of Android Applications
Bartsch, Steffen; Bunke, Michaela; Hofrichter, Oliver; Berger, Bernhard
2012-01-01
Mobile phones have developed into complex platforms with large numbers of installed applications and a wide range of sensitive data. Application security policies limit the permissions of each installed application. As applications may interact, restricting single applications may create a false sense of security for the end users while data may still leave the mobile phone through other applications. Instead, the information flow needs to be policed for the composite system of applications in a transparent and usable manner. In this paper, we propose to employ static analysis based on the software architecture and focused data flow analysis to scalably detect information flows between components. Specifically, we aim to reveal transitivity of trust problems in multi-component mobile platforms. We demonstrate the feasibility of our approach with Android applications, although the generalization of the analysis to similar composition-based architectures, such as Service-oriented Architecture, can also be explo...
Goldberg, Susan; And Others
This longitudinal study investigated the relationship of stress arising from medical problems of newborns to parent-infant interaction through the infant's first year. Significant interactive differences between full term and premature infants were found in feeding situations during the neonatal period and in floor play at eight months. The sample…
DYNAMIC SIMULATION OF FLUID-STRUCTURE INTERACTION PROBLEMS INVOLVING LARGE-AMPLITUDE SLOSHING
Chen Jianping; Zhou Rurong; Wu Wenlong
2004-01-01
An effective computational method is developed for dynamic analysis of fluid-structure interaction problems involving large-amplitude sloshing of the fluid and large-displacement motion of the structure.The structure is modeled as a rigid container supported by a system consisting of springs and dashpots.The motion of the fluid is decomposed into two parts: the large-displacement motion with the container and the large-amplitude sloshing relative to the container.The former is conveniently dealt with by defining a container-fixed noninertial local frame, while the latter is easily handled by adopting an ALE kinematical description.This leads to an easy and accurate treatment of both the fluid-structure interface and the fluid free surface without producing excessive distortion of the computational mesh.The coupling between the fluid and the structure is accomplished through the coupling matrices that can be easily established.Two numerical examples, including a TLD-structure system and a simplified liquid-loaded vehicle system, are presented to demonstrate the effectiveness and reliability of the proposed method.The present work can also be applied to simulate fluid-structure problems incorporating multibody systems and several fluid domains.
Rhodes, Jessica D; Colder, Craig R; Trucco, Elisa M; Speidel, Carolyn; Hawk, Larry W; Lengua, Liliana J; Das Eiden, Rina; Wieczorek, William
2013-01-01
A large literature suggests associations between self-regulation and motivation and adolescent problem behavior; however, this research has mostly pitted these constructs against one another or tested them in isolation. Following recent neural-systems based theories (e.g., Ernst & Fudge, 2009 ), the present study investigated the interactions between self-regulation and approach and avoidance motivation prospectively predicting delinquency and depressive symptoms in early adolescence. The community sample included 387 adolescents aged 11 to 13 years old (55% female; 17% minority). Laboratory tasks were used to assess self-regulation and approach and avoidance motivation, and adolescent self-reports were used to measure depressive symptoms and delinquency. Analyses suggested that low levels of approach motivation were associated with high levels of depressive symptoms, but only at high levels of self-regulation (p = .01). High levels of approach were associated with high levels of rule breaking, but only at low levels of self-regulation (p < .05). These findings support contemporary neural-based systems theories that posit integration of motivational and self-regulatory individual differences via moderational models to understand adolescent problem behavior. PMID:23477426
ADA ZHENG
2011-10-01
Full Text Available We have developed an innovative hybrid problem-based learning (PBL methodology. The methodology has the following distinctive features: i Each complex question was decomposed into a set of coherent finer subquestions by following the carefully designed criteria to maintain a delicate balance between guiding the students and inspiring them to think independently. This learning methodology enabled the students to solve the complex questions progressively in an inductive context. ii Facilitated by the utilization of our web-based learning systems, the teacher was able to interact with the students intensively and could allocate more teaching time to provide tailor-made feedback for individual student. The students were actively engaged in the learning activities, stimulated by the intensive interaction. iii The answers submitted by the students could be automatically consolidated in the report of the Moodle system in real-time. The teacher could adjust the teaching schedule and focus of the class to adapt to the learning progress of the students by analysing the automatically generated report and log files of the web-based learning system. As a result, the attendance rate of the students increased from about 50% to more than 90%, and the students’ learning motivation have been significantly enhanced.
Meyer Dirk
2012-02-01
Full Text Available Abstract Background The degree to which loud-calls in nonhuman primates can be used as a reliable taxonomic tool is the subject of ongoing debate. A recent study on crested gibbons showed that these species can be well distinguished by their songs; even at the population level the authors found reliable differences. Although there are some further studies on geographic and phylogenetic differences in loud-calls of nonhuman primate species, it is unclear to what extent loud-calls of other species have a similar close relation between acoustic structure, phylogenetic relatedness and geographic distance. We therefore conducted a field survey in 19 locations on Sumatra, Java and the Mentawai islands to record male loud-calls of wild surilis (Presbytis, a genus of Asian leaf monkeys (Colobinae with disputed taxanomy, and compared the structure of their loud-calls with a molecular genetic analysis. Results The acoustic analysis of 100 surili male loud-calls from 68 wild animals confirms the differentiation of P.potenziani, P.comata, P.thomasi and P.melalophos. In a more detailed acoustic analysis of subspecies of P.melalophos, a further separation of the southern P.m.mitrata confirms the proposed paraphyly of this group. In concordance with their geographic distribution we found the highest correlation between call structure and genetic similarity, and lesser significant correlations between call structure and geographic distance, and genetic similarity and geographic distance. Conclusions In this study we show, that as in crested gibbons, the acoustic structure of surili loud-calls is a reliable tool to distinguish between species and to verify phylogenetic relatedness and migration backgrounds of respective taxa. Since vocal production in other nonhuman primates show similar constraints, it is likely that an acoustic analysis of call structure can help to clarify taxonomic and phylogenetic relationships.
Lengua, L J; Wolchik, S A; Sandler, I N; West, S G
2000-06-01
Investigated the interaction between parenting and temperament in predicting adjustment problems in children of divorce. The study utilized a sample of 231 mothers and children, 9 to 12 years old, who had experienced divorce within the previous 2 years. Both mothers' and children's reports on parenting, temperament, and adjustment variables were obtained and combined to create cross-reporter measures of the variables. Parenting and temperament were directly and independently related to outcomes consistent with an additive model of their effects. Significant interactions indicated that parental rejection was more strongly related to adjustment problems for children low in positive emotionality, and inconsistent discipline was more strongly related to adjustment problems for children high in impulsivity. These findings suggest that children who are high in impulsivity may be at greater risk for developing problems, whereas positive emotionality may operate as a protective factor, decreasing the risk of adjustment problems in response to negative parenting. PMID:10802832
Kirschfink Michael
2010-07-01
Full Text Available Abstract Background In problem-based learning (PBL, tutors play an essential role in facilitating and efficiently structuring tutorials to enable students to construct individual cognitive networks, and have a significant impact on students' performance in subsequent assessments. The necessity of elaborate training to fulfil this complex role is undeniable. In the plethora of data on PBL however, little attention has been paid to tutor training which promotes competence in the moderation of specific difficult situations commonly encountered in PBL tutorials. Methods Major interactive obstacles arising in PBL tutorials were identified from prior publications. Potential solutions were defined by an expert group. Video clips were produced addressing the tutor's role and providing exemplary solutions. These clips were embedded in a PBL tutor-training course at our medical faculty combining PBL self-experience with a non-medical case. Trainees provided pre- and post-intervention self-efficacy ratings regarding their PBL-related knowledge, skills, and attitudes, as well as their acceptance and the feasibility of integrating the video clips into PBL tutor-training (all items: 100 = completely agree, 0 = don't agree at all. Results An interactive online tool for PBL tutor training was developed comprising 18 video clips highlighting difficult situations in PBL tutorials to encourage trainees to develop and formulate their own intervention strategies. In subsequent sequences, potential interventions are presented for the specific scenario, with a concluding discussion which addresses unresolved issues. The tool was well accepted and considered worth the time spent on it (81.62 ± 16.91; 62.94 ± 16.76. Tutors considered the videos to prepare them well to respond to specific challenges in future tutorials (75.98 ± 19.46. The entire training, which comprised PBL self-experience and video clips as integral elements, improved tutor's self-efficacy with
From video to computation of biological fluid-structure interaction problems
Dillard, Seth I.; Buchholz, James H. J.; Udaykumar, H. S.
2016-04-01
This work deals with the techniques necessary to obtain a purely Eulerian procedure to conduct CFD simulations of biological systems with moving boundary flow phenomena. Eulerian approaches obviate difficulties associated with mesh generation to describe or fit flow meshes to body surfaces. The challenges associated with constructing embedded boundary information, body motions and applying boundary conditions on the moving bodies for flow computation are addressed in the work. The overall approach is applied to the study of a fluid-structure interaction problem, i.e., the hydrodynamics of swimming of an American eel, where the motion of the eel is derived from video imaging. It is shown that some first-blush approaches do not work, and therefore, careful consideration of appropriate techniques to connect moving images to flow simulations is necessary and forms the main contribution of the paper. A combination of level set-based active contour segmentation with optical flow and image morphing is shown to enable the image-to-computation process.
Jaffee, Sara R.; Caspi, Avshalom; Moffitt, Terrie E; Dodge, Kenneth A.; Rutter, Michael,; Taylor, Alan; Tully, Lucy A.
2005-01-01
Maltreatment places children at risk for psychiatric morbidity, especially conduct problems. However, not all maltreated children develop conduct problems. We tested whether the effect of physical maltreatment on risk for conduct problems was strongest among those who were at high genetic risk for these problems using data from the E-risk Study, a representative cohort of 1,116 5-year-old British twin pairs and their families. Children's conduct problems were ascertained via parent and teache...
An Interactive Web-Based Learning NMR Spectroscopy course is developed to improve and facilitate student's learning as well as achievement of learning objectives in the concepts of multiplicity, chemical shift, and problem solving. This web-based learning course is emphasized on NMR problem solving, therefore, the concepts of multiplicity and chemical shift, basic concepts for practice problem solving, are also emphasized. Most of animations and pictures in this web-based learning are new created and simplified to explain processes and principles in NMR spectroscopy. With meaningful animations and pictures, simplified English language used, step-by-step problem solving, and interactive test, it can be self-learning web site and best on the student's convenience
Problem-Solving Examples as Interactive Learning Objects for Educational Digital Libraries
Brusilovsky, Peter; Yudelson, Michael; Hsiao, I-Han
2009-01-01
The paper analyzes three major problems encountered by our team as we endeavored to turn problem solving examples in the domain of programming into highly reusable educational activities, which could be included as first class objects in various educational digital libraries. It also suggests three specific approaches to resolving these problems,…
Local realizations of contact interactions in two- and three-body problems
Kruppa, A T; Révai, J
2001-01-01
Mathematically rigorous theory of the two-body contact interaction in three dimension is reviewed. Local potential realizations of this proper contact interaction are given in terms of Poschl-Teller, exponential and square-well potentials. Three body calculation is carried out for the halo nucleus 11Li using adequately represented contact interaction.
Baptista, Joana; Belsky, Jay; Marques, Sofia; Silva, Joana R; Oliveira, Paula; Mesquita, Ana; Martins, Carla; Soares, Isabel
2014-12-01
The current study extends research on the effects of institutionalization, most notably by examining whether-and how-both pre-institutional maltreatment in the family and the stability and consistency of institutional care interact to shape emotional and behavioral development. Fifty Portuguese children, placed in residential institutions when 8 days to 26 months of age, were evaluated using the Child Behavior Checklist when aged 18-31 months. Caregiver-rated internalizing and externalizing behavior problems proved to be unrelated to both early family and institutional experiences, as main effects, but the interaction of these factors significantly predicted externalizing problems: a history of maltreatment in the family coupled with unstable institutional caregiving arrangements predicted especially elevated levels of externalizing problems. Results are discussed in terms of the importance of more distal and proximate developmental experiences. PMID:25459985
Childhood problem behavior and parental divorce: evidence for gene–environment interaction
Robbers, Sylvana; Van Oort, Floor; Huizink, Anja; Verhulst, Frank; van Beijsterveldt, Toos; Boomsma, Dorret; Bartels, Meike
2012-01-01
textabstractObjective: The importance of genetic and environmental influences on children's behavioral and emotional problems may vary as a function of environmental exposure. We previously reported that 12-year-olds with divorced parents showed more internalizing and externalizing problems than children with married parents, and that externalizing problems in girls precede and predict later parental divorce. The aim of the current study was to investigate as to whether genetic and environmen...
Goodnight, Jackson A.; Bates, John E.; Pettit, Gregory S.; Dodge, Kenneth A.
2008-01-01
Longitudinal studies have found associations between parenting and the development of conduct problems, and have found that resistant to control temperament moderates these associations. Intervention studies have found associations between intervention-induced changes in parenting and subsequent reductions in children’s conduct problems. However, no study to date has evaluated whether parents’ self-initiated efforts to change their parenting practices affect children’s conduct problems and wh...
van Houwelingen, Anne H.; den Elzen, Wendy P.J.; le Cessie, Saskia; Blom, Jeanet W.; Gussekloo, Jacobijn
2015-01-01
This study explores the combination of four common health problems in older people and whether problems on four domains result in an additional effect on indicators of poor health. For this purpose, a total of 2681 participants (32% male, mean age 82 years) of the Integrated Systematic Care for Older People (ISCOPE) study were screened on the presence of health problems on four domains (functional, somatic, mental, social) with the postal ISCOPE questionnaire. Extensive interview data on heal...
Arbuzov, B A
2015-01-01
A possible effective interaction in the quantum gravity is considered. The compensation equation for a spontaneous generation of this interaction is shown to have a non-trivial solution. Would be consequences of a possible existence of effective interactions in the gravity theory are discussed. An example of running gravitational coupling is presented, which corresponds to a description of effects, which nowadays are prescribed to a dark mater and to a dark energy.
Childhood problem behavior and parental divorce: evidence for gene-environment interaction
S.C.C. Robbers (Sylvana); F.V.A. van Oort (Floor); A.C. Huizink (Anja); F.C. Verhulst (Frank); C.E.M. van Beijsterveldt (Toos); D.I. Boomsma (Dorret); M. Bartels (Meike)
2012-01-01
textabstractObjective: The importance of genetic and environmental influences on children's behavioral and emotional problems may vary as a function of environmental exposure. We previously reported that 12-year-olds with divorced parents showed more internalizing and externalizing problems than chi
M. Moret-Harman; R. Reuzel; J. Grin; C. Kramers; G.J. van der Wilt
2011-01-01
The quality of an evaluation largely depends on the quality of the underlying problem definition and the quality of the problem definition often improves as stakeholder involvement increases. By means of a study on the management of attempted suicides by drug overdose, we explored whether an interac
Thai, Khanh-Phuong; Son, Ji Y.; Hoffman, Jessica; Devers, Christopher; Kellman, Philip J.
2014-01-01
Mathematics is the study of structure but students think of math as solving problems according to rules. Students can learn procedures, but they often have trouble knowing when to apply learned procedures, especially to problems unlike those they trained with. In this study, the authors rely on the psychological mechanism of perceptual learning…
Kaplow, Roy; And Others
It is possible to separate the use of computers for instructional purposes into four modes, distinguished by the style of user interaction and sometimes by the implementation methods used. The four major modes are: 1) conversational, in which the interaction resembles an exchange between two persons; 2) data-based, wherein one component of the…
Marisa ePrzyrembel
2012-06-01
Full Text Available Successful human social interaction depends on our capacity to understand other people’s mental states and to anticipate how they will react to our actions. Despites its importance to the human condition, there are still quite a few debates about how we actually solve the problem of understanding other peoples’ actions, feelings and thoughts. Here we consider this problem from philosophical, psychological, and neuroscientific perspectives. In a critical review we show that attempts to draw parallels across these complementary levels of analysis are premature: The second-person perspective does not map directly to simulation theories, online social cognition or shared neural networks underlying action observation or empathy. Nor does the third-person perspective map onto theory-theory accounts of other agents mental states, offline social cognition or the neural networks that support Theory of Mind. We further propose that important qualities of social interaction emerge through the reciprocal interaction of two independent agents whose unpredictable behaviour requires a continual updating of models of their partner internal state. This analysis draws attention to the need for paradigms that allow two individuals to interact in a spontaneous and natural manner and to adapt their behaviour and cognitions in a response contingent fashion due to the unpredictability of their partners behaviour. Even if such paradigms were implemented, it is possible that the specific neural correlates supporting such reciprocal interaction would not reflect the processes unique to social interaction because much real social behaviour may reflect the use of basic cognitive and emotional process in a novel and unique manner. Given the role of social interaction in human evolution, ontogeny and every-day social life, a more theoretically and methodologically nuanced approach to the study of social interaction will help to shed new light on the dark matter of social
Calcavecchia, Francesco; Holzmann, Markus
2016-04-01
We use the shadow wave function formalism as a convenient model to study the fermion sign problem affecting all projector quantum Monte Carlo methods in continuum space. We demonstrate that the efficiency of imaginary-time projection algorithms decays exponentially with increasing number of particles and/or imaginary-time propagation. Moreover, we derive an analytical expression that connects the localization of the system with the magnitude of the sign problem, illustrating this behavior through numerical results. Finally, we discuss the computational complexity of the fermion sign problem and methods for alleviating its severity.
Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System
Bhende, C. N.; Kalam, A.; Malla, S. G.
2016-04-01
Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.
Archambeault, Betty
1993-01-01
Holistic math focuses on problem solving with numbers and concepts. Whole math activities for adults include shopping for groceries, eating in restaurants, buying gas, taking medicine, measuring a room, estimating servings, and compiling a family cookbook. (SK)
Gulland, E.-K.; B. Veenendaal; A. G. T. Schut
2012-01-01
Problem-solving knowledge and skills are an important attribute of spatial sciences graduates. The challenge of higher education is to build a teaching and learning environment that enables students to acquire these skills in relevant and authentic applications. This study investigates the effectiveness of traditional face-to-face teaching and online learning technologies in supporting the student learning of problem-solving and computer programming skills, techniques and solutions. ...
Non-perturbative Solution to the Quantum Interaction Problem via Schwinger's Action Principle
de Melo, C A M; Ramirez, J A
2016-01-01
The most realistic situations in quantum mechanics involve the interaction between two or more systems. In the most of reliable models, the form and structure of the interactions generate differential equations which are, in the most of cases, almost impossible to solve exactly. In this paper, using the Schwinger Quantum Action Principle, we found the time transformation function that solves exactly the harmonic oscillator interacting with a set of other harmonic coupled oscillators. In order to do it, we have introduced a new special set of creation and annihilation operators which leads directly to the \\emph{dressed states} associated to the system, which are the real quantum states of the interacting \\emph{\\textquotedblleft field-particle\\textquotedblright} system. To obtain the closed solution, it is introduced in the same foot a set of \\emph{normal mode} creation and annihilation operators of the system related to the first ones by an orthogonal transformation. We find the eigenstates, amplitude transiti...
Efficient Interactive Methods for a Class of Multiattribute Shortest Path Problems
Mordechai I. Henig
1994-01-01
Given an acyclic network and a preference-order relation on paths, when and how can Bellman's principle of optimality be combined with interactive programming to efficiently locate an optimal path? We show that if preferences are defined via a collection of attributes, then, under common conditions, the principle of optimality is valid if and only if the preferences can be represented by a linear (value) function over the attributes. Consequently, an interactive programming method is suggeste...
Confronting the missing epistasis problem: on the reproducibility of gene-gene interactions.
Murk, William; Bracken, Michael B; DeWan, Andrew T
2015-08-01
Epistasis (gene-gene interaction) is thought to play an integral role in the genetic basis of complex traits, and a significant amount of research has been invested into identifying this phenomenon in human disease. However, the overall success of empirical studies of epistasis in humans is unclear, as such studies are rarely systematically evaluated. Here, we have selected asthma as an example of a well-studied, complex human disease, and provide a critical analysis and replication attempt of nearly all prior reports of epistasis for this disease. Of 191 previously reported interactions, we find that 39.8% were not originally identified using an explicit test for interaction and thus may not have been true epistatic effects to begin with. Moreover, directions of effect were not described for 46.1% of the interactions, which prevents their rigorous replication. In the original studies, attempts at replication were made for 15.2% of the interactions, and 7.3% were actually replicated. In the current study, we were able to evaluate 85.9% of the interactions using a large asthma dataset from the GABRIEL Consortium. None of these interactions could be replicated based on strict criteria. However, we found nominally significant (p < 0.05) evidence in support of 23.8% of the evaluated interactions. Although many reports of epistasis are not robustly supported in the published literature, our results suggest that at least some of these reports may have been true-positive examples of epistasis. In general, improvements in empirical studies of epistasis are called for, in order to better understand the importance of this phenomenon in human disease. PMID:25998948
A note on the problems of plasma-neutral gas interaction
The presence of an immersed neutral gas affects the equilibrium and the instability and wave phenomena of magnetically confined plasmas. In this note attention is drawn to some areas for further research on plasma-neutral gas interaction, including the spatial distributions of plasma and neutral gas, relaxation times, constraints and limitations of gas blanket systems, interaction with radiation, oscillations and wave phenomena, as well as instabilities. (Auth.)
Melvin Ballera
2013-01-01
Full Text Available This paper examines the use of social network media at three aspects in African and Libyan perspective. Firstly, to use social network media as an open network learning environment that provide service for interaction necessary for learners to support socialization and collaboration during problem solving. Secondly, to use social media as a tool to support blended learning in e-learning system and encourage non-native English students to express their ideas and fill the gap of communication problems. Thirdly, to analyze the interaction of the learner in social media threaded messages and its relation to group and individual performance using different social schema and social network analyses. Quasi-experimental results indicate that there is an increase on the cognitive level of students at different level while qualitative results reveal that it helps deepen learning, memorable, have freedom to express opinions and lessen pressure and increase communication and socialization.
Wong, P. K.
1975-01-01
The closely-related problems of designing reliable feedback stabilization strategy and coordinating decentralized feedbacks are considered. Two approaches are taken. A geometric characterization of the structure of control interaction (and its dual) was first attempted and a concept of structural homomorphism developed based on the idea of 'similarity' of interaction pattern. The idea of finding classes of individual feedback maps that do not 'interfere' with the stabilizing action of each other was developed by identifying the structural properties of nondestabilizing and LQ-optimal feedback maps. Some known stability properties of LQ-feedback were generalized and some partial solutions were provided to the reliable stabilization and decentralized feedback coordination problems. A concept of coordination parametrization was introduced, and a scheme for classifying different modes of decentralization (information, control law computation, on-line control implementation) in control systems was developed.
Melvin Ballera; Ismail Ateya Lukandu; Abdalla Radwan
2013-01-01
This paper examines the use of social network media at three aspects in African and Libyan perspective. Firstly, to use social network media as an open network learning environment that provide service for interaction necessary for learners to support socialization and collaboration during problem solving. Secondly, to use social media as a tool to support blended learning in e-learning system and encourage non-native English students to express their ideas and fill the gap of communication p...
Petr Štourač; Hana Harazim; Daniel Schwarz; Ivo Křikava; Martin Komenda; Roman Štoudek; Olga Smékalová; Martina Kosinová; Richard Hůlek; Jan Maláska; Radim Šustr; Ivo Šnábl; Ladislav Dušek; Roman Gál
2013-01-01
This paper describes the interactive tools of the AKUTNE.CZ (part of MEFANET) and SEPSIS-Q portals for Problem Based Learning (PBL) sessions in medical education. The portals aim to be a comprehensive source of information and educational materials, covering all aspects of acute medicine for undergraduate medical students and health professionals. Our focus is mainly on simulation-based tools for teaching and learning algorithms in acute patient care, the backbone of the AKUTNE.CZ and SEPSIS-...
Popolo, A. Del [Dipartimento di Fisica e Astronomia, University Of Catania, Viale Andrea Doria 6, 95125 Catania (Italy); Delliou, M. Le, E-mail: adelpopolo@oact.inaf.it, E-mail: delliou@ift.unesp.br [Instituto de Fisica Teorica IFT-UNESP, Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2 - Barra Funda, 01140-070 São Paulo, SP Brazil (Brazil)
2014-12-01
We continue the study of the impact of baryon physics on the small scale problems of the ΛCDM model, based on a semi-analytical model (Del Popolo, 2009). With such model, we show how the cusp/core, missing satellite (MSP), Too Big to Fail (TBTF) problems and the angular momentum catastrophe can be reconciled with observations, adding parent-satellite interaction. Such interaction between dark matter (DM) and baryons through dynamical friction (DF) can sufficiently flatten the inner cusp of the density profiles to solve the cusp/core problem. Combining, in our model, a Zolotov et al. (2012)-like correction, similarly to Brooks et al. (2013), and effects of UV heating and tidal stripping, the number of massive, luminous satellites, as seen in the Via Lactea 2 (VL2) subhaloes, is in agreement with the numbers observed in the MW, thus resolving the MSP and TBTF problems. The model also produces a distribution of the angular spin parameter and angular momentum in agreement with observations of the dwarfs studied by van den Bosch, Burkert, and Swaters (2001)
Del Popolo, Antonino
2014-01-01
We {\\bf continue the study of the impact from} baryon physics on the small scale problems of the $\\Lambda$CDM model{\\bf, based on a semi-analytical model (Del Popolo, 2009). With such model, we show how the cusp/core, missing satellite (MSP), Too Big to Fail (TBTF) problems} and the angular momentum catastrophe can be reconciled with observations{\\bf, adding parent-sattelite interaction. Such interaction} between dark matter (DM) and baryons through dynamical friction (DF) can {\\bf sufficiently} flatten the inner cusp of the density profiles to solve the cusp/core problem. {\\bf Combining, in our model, a Zolotov et al. (2012)-like correction, similarly to Brooks et al. (2013), and effects of UV heating and tidal stripping, the number of massive, luminous satellites, as seen in the Via Lactea 2 (VL2) subhaloes,} is in agreement with the numbers observed in the MW, thus resolving the MSP and TBTF problems. The model also produces {\\bf a distribution of the angular spin parameter and angular momentum in agreemen...
We continue the study of the impact of baryon physics on the small scale problems of the ΛCDM model, based on a semi-analytical model (Del Popolo, 2009). With such model, we show how the cusp/core, missing satellite (MSP), Too Big to Fail (TBTF) problems and the angular momentum catastrophe can be reconciled with observations, adding parent-satellite interaction. Such interaction between dark matter (DM) and baryons through dynamical friction (DF) can sufficiently flatten the inner cusp of the density profiles to solve the cusp/core problem. Combining, in our model, a Zolotov et al. (2012)-like correction, similarly to Brooks et al. (2013), and effects of UV heating and tidal stripping, the number of massive, luminous satellites, as seen in the Via Lactea 2 (VL2) subhaloes, is in agreement with the numbers observed in the MW, thus resolving the MSP and TBTF problems. The model also produces a distribution of the angular spin parameter and angular momentum in agreement with observations of the dwarfs studied by van den Bosch, Burkert, and Swaters (2001)
Li, Hong; Zhang, Li; Jiao, Yong-Chang
2016-07-01
This paper presents an interactive approach based on a discrete differential evolution algorithm to solve a class of integer bilevel programming problems, in which integer decision variables are controlled by an upper-level decision maker and real-value or continuous decision variables are controlled by a lower-level decision maker. Using the Karush--Kuhn-Tucker optimality conditions in the lower-level programming, the original discrete bilevel formulation can be converted into a discrete single-level nonlinear programming problem with the complementarity constraints, and then the smoothing technique is applied to deal with the complementarity constraints. Finally, a discrete single-level nonlinear programming problem is obtained, and solved by an interactive approach. In each iteration, for each given upper-level discrete variable, a system of nonlinear equations including the lower-level variables and Lagrange multipliers is solved first, and then a discrete nonlinear programming problem only with inequality constraints is handled by using a discrete differential evolution algorithm. Simulation results show the effectiveness of the proposed approach.
Zhu, Zheng; Andresen, Juan Carlos; Moore, M A; Katzgraber, Helmut G
2014-02-01
We study the equilibrium and nonequilibrium properties of Boolean decision problems with competing interactions on scale-free networks in an external bias (magnetic field). Previous studies at zero field have shown a remarkable equilibrium stability of Boolean variables (Ising spins) with competing interactions (spin glasses) on scale-free networks. When the exponent that describes the power-law decay of the connectivity of the network is strictly larger than 3, the system undergoes a spin-glass transition. However, when the exponent is equal to or less than 3, the glass phase is stable for all temperatures. First, we perform finite-temperature Monte Carlo simulations in a field to test the robustness of the spin-glass phase and show that the system has a spin-glass phase in a field, i.e., exhibits a de Almeida-Thouless line. Furthermore, we study avalanche distributions when the system is driven by a field at zero temperature to test if the system displays self-organized criticality. Numerical results suggest that avalanches (damage) can spread across the whole system with nonzero probability when the decay exponent of the interaction degree is less than or equal to 2, i.e., that Boolean decision problems on scale-free networks with competing interactions can be fragile when not in thermal equilibrium. PMID:25353433
Eulerian method for fluid-structure interaction and submerged solid-solid contact problems
Valkov, Boris; Kamrin, Ken
2014-01-01
We present a fully Eulerian, blurred-interface numerical method for fluid-structure interaction (FSI) with extension to the case of fluid-immersed solids interacting through contact. The method uses the Eulerian-frame Reference Map Technique (RMT) to represent the solid phase(s), permitting simulation of large-deformation constitutive behaviors. We demonstrate the method with multiple examples involving a compressible Navier-Stokes fluid coupled to a neo-Hookean solid. We verify the method's convergence. The algorithm is faster and more stable than previous methods based on RMT. It is easily appended with a contact subroutine for multiple solids interacting within fluid, which we introduce and demonstrate with two examples.
The nucleon-nucleon interaction and the nuclear many-body problem
In this review we wish to relate effective forces in nuclear matter and in nuclei back to the interaction between two isolated nucleons. Low-brow meson theory is used to derive the nucleon-nucleon interaction, with dispersion theoretical calculations as a guide, and a certain amount of phenomenology to pin down the parameters. A chiral picture is in the back of our mind, but since the main approach here is a semi-phenomenological one, chiral invariance is not developed in detail. (orig.)
The nucleon-nucleon interaction and the nuclear many-body problem
In this review we wish to relate effective forces in nuclear matter and in nuclei back to the interaction between two isolated nucleons. Low-brow meson theory is used to derive the nucleon-nucleon interaction, with dispersion theoretical calculations as a guide, and a certain amount of phenomenology to pin down the parameters. A chiral picture is in the back of our mind, but since the main approach here is a semi-phenomenological one, chiral invariance is not developed in detail. (orig./WL)
Coley, Rebekah Levine; Carrano, Jennifer; Lewin-Bizan, Selva
2011-01-01
Building upon previous evidence for the intergenerational transmission of antisocial behaviors, this research assessed and compared three models seeking to explain links between fathers' antisocial behaviors and children's behavior problems. A representative sample of children from low-income families (N = 261) was followed from age 3 through age…
Global stability for an inverse problem in soil-structure interaction
Alessandrini, Giovanni; Morassi, Antonino; Rosset, Edi; Vessella, Sergio
2015-01-01
We consider the inverse problem of determining the Winkler subgrade reaction coefficient of a slab foundation modelled as a thin elastic plate clamped at the boundary. The plate is loaded by a concentrated force and its transversal deflection is measured at the interior points. We prove a global H\\"{o}lder stability estimate under (mild) regularity assumptions on the unknown coefficient.
Burt, Keith B.; Paysnick, Amy A.
2014-01-01
The present study examined sense of identity (assessed using the Identity subscale of the Psychosocial Maturity Inventory) as a moderator of associations between stressful life events, behavioral/emotional problems, and substance abuse in a sample of 187 college undergraduates (67% female). Correlations showed evidence for positive associations…
Solvability of an unsaturated porous media flow problem with thermomechanical interaction
Albers, Bettina; Krejci, Pavel; Rocca, Elisabetta
2016-01-01
A PDE system consisting of the momentum balance, mass balance, and energy balance equations for displacement, capillary pressure, and temperature as a model for unsaturated fluid flow in a porous viscoelastoplastic solid is shown to admit a solution under appropriate assumptions on the constitutive behavior. The problem involves two hysteresis operators accounting for plastic and capillary hysteresis.
Gene-by-Preschool Interaction on the Development of Early Externalizing Problems
Tucker-Drob, Elliot M.; Harden, K. Paige
2013-01-01
Background: Preschool involves an array of new social experiences that may impact the development of early externalizing behavior problems over the transition to grade school. Methods: Using longitudinal data from a nationally representative sample of over 600 pairs of US twins, we tested whether the genetic and environmental influences on…
Solution recommended by the CEA to minimize fuel-cladding interaction problems
To improve behavior of fuel elements under fast variation of power, the CEA developed a fracture resistant fuel: UO2 DCI and a cladding with low creep under irradiation: strong zircaloy 4. This paper gives main characteristics of these new materials and shows at what extent a better behavior of fuel pins is obtained concerning fuel-cladding interaction
Seven-step problem-based learning in an interaction design course
Schultz, Nette; Christensen, Hans Peter
2004-01-01
The objective in this paper is the implementation of the highly structured seven-step PBL procedure as part of the learning process in a human-computer interaction design course at the Technical University of Denmark, taking into account the common learning processes in PBL and the interaction de...... others in a single course. The evaluation results showed that the students definitely took a deep approach to learning, and indicated clearly that the students had obtained competences not only within the traditional HCI curriculum but also in terms of team-work skills.......The objective in this paper is the implementation of the highly structured seven-step PBL procedure as part of the learning process in a human-computer interaction design course at the Technical University of Denmark, taking into account the common learning processes in PBL and the interaction...... individual reports after each case in the PBL-process in order to explore the students’ inter- and intra-personal team skills development in the learning process. Different qualitative and quantitative evaluation methods have been used to obtain a thorough evaluation of PBL used as a learning method among...
Hernandez-Cortes, Patricia
2012-01-01
Vitellogenin (Vtg) is a lipid transfer protein that carries yolk to the ovary. The vitellogenin receptor (VtgR) mediates the uptake of Vtg into the oocyte of oviparous animals; its structure includes eight ligand-binding repeats (LBR). The binding site of VtgR and Vtg and the location of the interaction within the molecules are at these LBR.…
A technical assessment of the critical issues and problem areas in the field of plasma materials interactions (PMI) in magnetic fusion devices shows these problems to be central for near-term experiments, for intermediate-range reactor devices including D-T burning physics experiments, and for long-term reactor machines. Critical technical issues are ones central to understanding and successful operation of existing and near-term experiments/reactors or devices of great importance for the long run, i.e., ones which will require an extensive, long-term development effort and thus should receive attention now. Four subgroups were formed to assess the critical PMI issues along four major lines: (1) PMI and plasma confinement physics experiments; (2) plasma-edge modelling and theory; (3) surface physics; and (4) materials technology for in-vessel components and the first wall. The report which follows is divided into four major sections, one for each of these topics
Problem solving - an interactive active method for teaching the thermokinetic concept
Odochian Lucia
2014-07-01
Full Text Available The paper describes a strategy that uses problem solving to teach the thermokinetic concept, based on student’s previously established proficiency in thermochemistry and kinetics. Chemistry teachers often use this method because it ensures easy achievement of both formative and informative science skills. This teaching strategy is tailored for students that prove special intellectual resources, Olympiad participants and to those who find chemistry a potential professional route
Feistauer, M.; Sváček, P.; Horáček, Jaromír
1. Basel : Birkhäuser, 2014 - (Bodnár, T.; Galdi, G.; Nečasová, Š.), s. 321-394 ISBN 978-3-0348-0821-7. - (Advances in Mathematical Fluid Mechanics) R&D Projects: GA ČR(CZ) GAP101/11/0207 Institutional support: RVO:61388998 Keywords : aeroelasticity * ALE method * dynamic elasticity problem * vocal folds Subject RIV: BI - Acoustics
ADA ZHENG; YAN ZHOU
2011-01-01
We have developed an innovative hybrid problem-based learning (PBL) methodology. The methodology has the following distinctive features: i) Each complex question was decomposed into a set of coherent finer subquestions by following the carefully designed criteria to maintain a delicate balance between guiding the students and inspiring them to think independently. This learning methodology enabled the students to solve the complex questions progressively in an inductive context. ii) Facilitat...
Child behavior problems among cocaine-exposed toddlers: Indirect and interactive effects
Eiden, Rina D.; Granger, Douglas A.; Schuetze, Pamela; Veira, Yvette
2011-01-01
This study examined the role of maternal psychopathology and maternal warmth as mediators of the association between prenatal cocaine and other substance exposure and toddler behavior problems. It was also hypothesized that infant cortisol reactivity and environmental risk may moderate these associations. Participants were 220 caregiver–infant dyads (119 cocaine exposed, 101 not cocaine exposed; 49% boys). Mother–infant dyads were recruited at delivery with assessments at 4–8 weeks and 7, 13,...
In non-relativistic approximation, the SU(2) gauge group Yang-Mills equations with two quasistatic sources are shown to be reduced to the set of elliptic equations analogous to that of non-linear electrodynamics. The regular solutions of the obtained equations are discussed. An interpretation of the behavior of the quark field in such gluon configuration is given. The results of numerical calculations are discussed and two-body problem is analyzed
Zinoubi, J.; Maad, R.B.; Belghith, A. [Faculte des Sciences de Tunis, Tunis (Tunisia). Departement de Physique, Laboratoire d' Energetique et des Transferts de Chaleur et de Masse
2005-03-01
The quality of the surrounding air depends on the various dismissals of the combustion gases (exhaust cars, smokes of chimneys, ...), their scattering in the environment. Urban development around industrial zones and overexploitation of lands near factories triggered responsible interest in the problem of pollution. In order to decrease the impact of air pollution, several chimneys have been constructed in the different industrial facilities. So the improvement of the industrial chimney range became one of the current research problems. In order to improve the industrial chimney efficiency and to increase the vertical scattering of combustion products, we studied a system that could be integrated to the industrial chimney exit. This system is essentially constituted of an open-ended vertical cylinder of larger diameter. Thermal radiance emitted by smoke heats the internal cylinder wall. The heating of the fluid at the cylinder-inlet is the cause of the thermosiphon effect around the thermal plume. To study the problem in the laboratory we simulated the plume exiting of a chimney by a disk heated uniformly by the Joule effect at constant temperature. Different configurations were studied, while acting, on the source-cylinder spacing and the cylinder height. The study of the average fields permits, in a first stage, to get better information about the mechanism of the resulting flow development, and in a second stage, to determine the spacing of the source-cylinder and cylinder height optima, for which a clean increase of fluid flow rate is obtained. (author)
Site response - a critical problem in soil-structure interaction analyses for embedded structures
Soil-structure interaction analyses for embedded structures must necessarily be based on a knowledge of the manner in which the soil would behave in the absence of any structure - that is on a knowledge and understanding of the spatial distribution of motions in the ground within the depth of embedment of the structure. The nature of these spatial variations is discussed and illustrated by examples of recorded motions. It is shown that both the amplitude of peak acceleration and the form of the acceleration response spectrum for earthquake motions will necessarily vary with depth and failure to take these variations into account may introduce an unwarranted degree of conservatism into the soil-structure interaction analysis procedure
The classical relativistic two-body problem with spin and self-interactions
The recent classical model of a spinning Dirac particle with Zitterbewegung is generalized to two particles interacting electromagnetically. A variational principle is formulated which leads to covariant Hamiltonian with separate centre of mass and relative terms much like the quantum 2-body Dirac equation. The relative motion has the same form as the spinless case but with the time dependent modulated coupling constant representing the spin effects. The canonical quantization of the theory is immediate. (author). 10 refs
On the problem of parameterizing ice shelf-ocean interaction in global climate models
Hellmer, Hartmut
2005-01-01
Sensitivity studies for the Southern Ocean indicate that freshwater fluxes from various sources have a significant impact on the stability of the water column with consequences for sea ice and water mass characteristics. These sources are either atmospheric or result from ocean interaction with the base of Antarctic ice shelves and drifting icebergs. The resolution of global climate models does not allow for an adequate representation of the processes on polar continental shelves. Therefore, ...
Mpofu, D J; Lanphear, J; Stewart, T; Das, M; Ridding, P; Dunn, E
1998-09-01
The Faculty of Medicine and Health Sciences (FMHS), United Arab Emirates (UAE) University is in a unique position to explore issues related to English language proficiency and medical student performance. All students entering the FMHS have English as a second language. This study focused on the issues of students' proficiency in English as measured by the TOEFL test, student background factors and interaction in problem-based learning (PBL) groups. Using a modification of Bales Interaction Process Analysis, four problem-based learning groups were observed over four thematic units, to measure the degree of student interaction within PBL groups and to compare this to individual TOEFL scores and key background variables. The students' contributions correlated highly with TOEFL test results in the giving of information (range r = 0.67-0.74). The female students adhered to interacting in English during group sessions, whereas the male students were more likely to revert to using Arabic in elaborating unclear phenomena (p TOEFL scores for the male students, but not for female students. Multivariate analysis was undertaken to analyse the relative contribution of the TOEFL, parental education and years of studying in English. The best predictor of students' contributions in PBL groups was identified as TOEFL scores. The study demonstrates the importance of facilitating a locally acceptable level of English proficiency prior to admission to the FMHS. However, it also highlights the importance of not focusing only on English proficiency but paying attention to additional factors in facilitating medical students in maximizing benefits from interactions in PBL settings. PMID:10211288
Existence of a solution to a fluid-multi-layered-structure interaction problem
Muha, Boris; Canic, Suncica
2013-01-01
We study a nonlinear, unsteady, moving boundary, fluid-structure (FSI) problem in which the structure is composed of two layers: a thin layer which is in contact with the fluid, and a thick layer which sits on top of the thin structural layer. The fluid flow, which is driven by the time-dependent dynamic pressure data, is governed by the 2D Navier-Stokes equations for an incompressible, viscous fluid, defined on a 2D cylinder. The elastodynamics of the cylinder wall is governed by the 1D line...
Application of the Salpeter equation to the problem of describing quark-antiquark interaction
Various methods for solving the Salpeter equation for spinless particles, including a new method proposed here and the semiclassical approximation, are considered. It is shown that the heavy-quarkonium masses derived from the Salpeter equation with an effective QCD potential are in excellent agreement with experimental data. The efficiency of approximate methods is illustrated by considering the example of a Coulomb potential. The semiclassical spectrum is calculated-in particular, with allowance for color Coulomb interaction. The dynamical quark masses and the spectra of charmonia and bottomonia are calculated within various approximations
The application of interactive computer graphics to nuclear data evaluation problems
A comprehensive semi-automated data evaluation system is being developed at Atomics International, in order to overcome many of the deficiencies associated with the application of available nuclear data evaluation methods to the more detailed, systematic, and accurate data evaluations currently required. Interactive .computational techniques enable the computer to form displays on a screen, and to sense, interpret, and relate the displayed information in real time. These techniques not only permit the rapid display of data sets selected at random, but also allow the evaluator to perform a large number of sequential operations in a short time span. The evaluator can take full advantage of his experience in interpreting results at each operational step. Thus, a logical path may be followed through to conclusion, without intervening lengthy delays. A prototype interactive data evaluation system, SCORE, is currently being used in support of the ENDF/B national neutron cross-section evaluation effort. SCORE provides a unique data storage, manipulation, and retrieval system for experimental data stored on SCISRS I data tapes. Other operational modules include: (1) an interactive method for fitting multilevel resonance parameters, using either Breit-Wigner or Reich-Moore theory, (2) a method for fitting analytical cubic spline curves to experimental data, and (3) a method of intercomparing, by visually displayed overlays, ENDF/B evaluated data with SCISRS I experimental data tapes. Other operational modules include: (]) an interactive method for fitting multilevel resonance parameters, using either Breit-Wigner or Reich-Moore theory, (2) a method for fitting analytical cubic spline curves to experimental data, and (3) a method of intercomparing, by visually displayed overlays, ENDF/B evaluated data with SCISRS I experimental data. The SCORE system is currently being further expanded in several ways. These include: (1) incorporating the Adler-Adler resonance region
Problems with initial and final state interactions in deep inelastic scattering
Although there exists a vast literature devoted to the theory of deep inelastic scattering, the restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group have not been considered. We argue that the standard parton model results take place in the situation when the current operator does not properly commute with the representation operators of the Lorentz group. At the same time, in models with the correct commutation relations the initial and final state interactions of the struck quark with the remnants of the target cannot be neglected even in the Bjorken limit. (author). 27 refs
Phenomenon of Cross-Cultural Interaction: Problem of Non-Linear Modeling
Marina Mogeiko
2011-04-01
Full Text Available Interaction of cultural traditions breaks an equilibrium condition of a cultural environment and results in destruction of opposition between ortodoxy (axyological center and periphery (alternative tendencies of culture. A cultural environment loses potential of semantic and axyological stability. By virtue of it a nonequilibrium situation can be resolved neither by prevalence of one of traditions nor by their mutual destruction as well as an additive synthesis of their maintenances – it assumes actualization of creative potential of culture and formation of new traditions.
Solving the detour problem in navigation: A model of prefrontal and hippocampal interactions
Hugo J Spiers
2015-03-01
Full Text Available Adapting behavior to accommodate changes in the environment is an important function of the nervous system. A universal problem for motile animals is the discovery that a learned route is blocked and detour is required. Given the substantial neuroscience research on spatial navigation and decision-making it is surprising that so little is known about how the brain solves the detour problem. Here we review the limited number of relevant functional neuroimaging, single unit recording and lesion studies. We find that while the prefrontal cortex consistently responds to detours, the hippocampus does not. Recent evidence suggests the hippocampus tracks information about the future path distance to the goal. Based on this evidence we postulate a conceptual model in which: Lateral prefrontal cortex provides a prediction error signal about the change in the path, frontopolar and superior prefrontal cortex support the re-formulation of the route plan as a novel subgoal and the hippocampus simulates the new path. More data will be required to validate this model and understand 1 how the system processes the different options and 2 deals with situations where a new path becomes available (i.e. shortcuts.
Shock-interface interaction: Current research on the Richtmyer- Meshkov problem
Rupert, V.
1991-07-17
The basis for the study of the evolution of a shocked interface stems from the question of the Rayleigh-Taylor (RT) instability (Taylor 1950). Starting in the late 18th century, the stability of an interface submitted to gravitational forces was investigated for the case in which the density of one of the materials across the interface was negligible compared to the other. Taylor analyzed the case in which the Atwood number (ratio of the difference of the densities to their sum) is less than 1, and the acceleration of the system is constant. He determined that the interface was unstable to small perturbations only if the direction of the acceleration normal to the interface coincides with that of the density gradient. Richtmyer (1960) extended Taylor's analysis to the case of an implusive acceleration. His results implied that the interface would be unstable irrespective of the relative orientation of the velocity impulse and the density gradient. His predictions were verified experimentally by Meshkov (1969), and the Richtmyer-Meshkov (RM) instability became a subject of research in its own right. Experimental, numerical, and theoretical works address this problem. The RM problem has been studied with both the shock-tube and laser experiments. In this paper, only shock-tube work is considered. 48 refs., 6 figs.
The late Universe with non-linear interaction in the dark sector: the coincidence problem
Bouhmadi-López, Mariam; Zhuk, Alexander
2016-01-01
We study the Universe at the late stage of its evolution and deep inside the cell of uniformity. At such a scale the Universe is highly inhomogeneous and filled with discretely distributed inhomogeneities in the form of galaxies and groups of galaxies. As a matter source, we consider dark matter (DM) and dark energy (DE) with a non-linear interaction $Q = 3\\mathcal{H}\\gamma \\overline\\varepsilon_{\\mathrm{DE}} \\overline\\varepsilon_{\\mathrm{DM}} / (\\overline\\varepsilon_{\\mathrm{DE}} + \\overline\\varepsilon_{\\mathrm{DM}})$, where $\\gamma$ is a constant. We assume that DM is pressureless and DE has a constant equation of state parameter $w$. In the considered model, the energy densities of the dark sector components present a scaling behaviour with $\\overline\\varepsilon_{\\mathrm{DM}} / \\overline\\varepsilon_{\\mathrm{DE}} \\sim \\left({a_0} / {a} \\right)^{-3(w+\\gamma)}$. We investigate the possibility that the perturbations of DM and DE, which are interacting among themselves, could be coupled to the galaxies with the ...
In this paper gradient based shape design optimization of strongly coupled fluid-structure interaction problems between a viscous, incompressible fluid and an elastic solid undergoing large displacement is investigated. This topic has received much interest in recent years. The viscous incompressible flow can be laminar or turbulent and is described using the Reynolds-Averaged Navier-Stokes equations (RANS) together with one- and two-equation turbulence models. The turbulence models used include both the algebraic Baldwin-Lomax turbulence model, the Spalart-Allmaras one-equation model and two-equation models such as the Wilcox 1988 and 1998 κ - ω turbulence models and the shear stress transport (SST) κ - ω turbulence model. The solution for state of the 2D/3D stationary fluid-structure interaction problem is obtained using both Galerkin, Streamline-Upwind/Petrov-Galerkin and Pressure-Stabilized/Petrov-Galerkin FEM, and due to the large displacements allowed, the finite element mesh of the fluid domain has to be updated as part of the solution algorithm. The mesh is updated by solving an auxiliary elastic problem for the fluid mesh, considering the fluid as a linear elastic solid and imposing the calculated solid displacements found from the coupled problem as nodal displacements. The resulting nonlinear equations are solved using an approximate Newton method and design sensitivity analysis is performed using the direct differentiation approach. The use of an inexact Jacobian matrix in the analysis leads to an iterative but very efficient scheme for sensitivity analysis. Several 2D and 3D gradient based shape optimization examples will illustrate the potential of the proposed methods in the fields of aero- and hydroelasticity. Refs. 6 (author)
Petr Štourač
2013-10-01
Full Text Available This paper describes the interactive tools of the AKUTNE.CZ (part of MEFANET and SEPSIS-Q portals for Problem Based Learning (PBL sessions in medical education. The portals aim to be a comprehensive source of information and educational materials, covering all aspects of acute medicine for undergraduate medical students and health professionals. Our focus is mainly on simulation-based tools for teaching and learning algorithms in acute patient care, the backbone of the AKUTNE.CZ and SEPSIS-Q portals. Over the last five years, more than 30 interactive algorithms in the Czech and English languages (http://www.akutne.eu have been developed and published online, allowing users to test and improve their knowledge and skills in the field of acute medicine. Additionally, we have created six SEPSIS-Q interactive scenarios in the Czech version. The peer-reviewed algorithms were used for conducting PBL-like sessions in General Medicine (First Aid, Anaesthesiology and Pain Management, Emergency Medicine and in Nursing (Obstetric Analgesia and Anaesthesia for Midwives, Intensive Care Medicine. The interactive scenarios serve to demonstrate interesting cases, with preference for Intensive Care Medicine sessions in General Medicine and Nursing.
Brown, P.J. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1996-11-01
A semi-quantitative analysis is given of some of the ways in which spin-lattice interactions can modify the cross-sections observable in neutron scattering experiments. This analysis is applied to the scattering from the invar alloy Fe{sub 65}Ni{sub 35} using a model in which the magnetic moment is a function of the near neighbour separation. This model has been applied to clarify the results of inelastic scattering experiments carried out on Fe{sub 65}Ni{sub 35} using both polarised and unpolarised neutrons. The extra information obtainable using polarised neutrons as well as the difficulties and limitations of the technique for inelastic scattering are discussed. (author) 8 figs., 14 refs.
On the weak solution of the fluid-structure interaction problem for shear-dependent fluids
Hundertmark, A.; Medviďová-Lukáčová, M.; Nečasová, Šárka
Basel: Springer, 2016 - (Amann, H.; Giga, Y.; Kozono, H.; Okamoto, H.; Yamazaki, M.), s. 291-319. (Advances in Mathematical Fluid Mechanics). ISBN 978-3-0348-0938-2. ISSN 2297-0320. [International Conference on Mathematical Fluid Dynamics on the Occasion of Yoshihiro Shibata’s 60th Birthday. Nara (JP), 05.03.2013-09.03.2013] R&D Projects: GA ČR(CZ) GAP201/11/1304; GA MŠk LC06052 Institutional support: RVO:67985840 Keywords : existence of weak solution * fluid-structure interaction * hemodynamics Subject RIV: BA - General Mathematics http://link.springer.com/chapter/10.1007%2F978-3-0348-0939-9_16
After having determined the structural properties of smectic liquid crystals made from double chain surfactants/water binary systems, residual anisotropic interactions and relaxation times measurements were used to investigate the molecular ordering. Phosphorus, deuterium and nitrogen NMR of the surfactant molecules evidenced their high degree of order and the strong anisotropy of their motions. Quantitative results depended on the surfactant polar head -phosphate or ammonium-, while they displayed little variations with the hydrocarbon tail size. The marked dependence of the order and dynamics of small solutes in a lamellar phase on their hydrophilic or hydrophobic behaviour was shown using the same methods. By means of para-magnetically induced relaxation, it was proved that the non-polar solute benzene is located in the organic domain of the liquid crystalline matrix. (author)
Interacting star clusters in the LMC Overmerging problem solved by cluster group formation
Leon, S; Vallenari, A
1999-01-01
We present the tidal tail distributions of a sample of candidate binary clusters located in the bar of the Large Magellanic Cloud (LMC). One isolated cluster, SL 268, is presented in order to study the effect of the LMC tidal field. All the candidate binary clusters show tidal tails, confirming that the pairs are formed by physically linked objects. The stellar mass in the tails covers a large range, from $1.8\\times 10^3$ to $3\\times 10^4$\\msun. We derive a total mass estimate for SL 268 and SL 356. At large radii, the projected density profiles of SL 268 and SL 356 fall off as $r^{-\\gamma}$, with $\\gamma= 2.27$ and $\\gamma=3.44$, respectively. Out of 4 pairs or multiple systems, 2 are older than the theoretical survival time of binary clusters (going from a few $10^6$ yr to $10^8$ yr). A pair shows too large age difference between the components to be consistent with classical theoretical models of binary cluster formation (Fujimoto & Kumai 1997). We refer to this as the ``overmerging'' problem.A differe...
Janssens, Annelies; Van Den Noortgate, Wim; Goossens, Luc; Verschueren, Karine; Colpin, Hilde; De Laet, Steven; Claes, Stephan; Van Leeuwen, Karla
2015-07-01
Molecular gene-by-environment studies primarily have focuses on the parent-child relationship as an environmental factor, whereas studies including peer relationships as environmental factor are rare. However, the effects of the peer context may not be the same for all adolescents due to biological characteristics. This study examined whether the effects of peer rejection and acceptance on externalizing behavior depend upon adolescents' genotype for the dopamine transporter (DAT1) or receptor D4 (DRD4) gene. In a sample of 563 adolescents (52% girls; Mage = 13.81), saliva samples, within-classroom peer nominations, and multi-informant behavior ratings were collected. Peer rejection, but not acceptance, was associated with externalizing problems. One out of eight models tested for rule-breaking behavior showed genetic moderation. According to the Roisman criteria, there was evidence for the differential susceptibility hypothesis. DAT1 10R carriers showed more rule-breaking behavior according to parents when experiencing high peer rejection, but less rule-breaking behavior when experiencing low peer rejection. The long DRD4 variant was associated with less aggression, but no moderation effects were found. The results are discussed in light of the differential susceptibility hypothesis and the reward sensitivity mechanism. PMID:26006708
J Haabrekke, Kristin; Siqveland, Torill; Smith, Lars; Wentzel-Larsen, Tore; Walhovd, Kristine B; Moe, Vibeke
2015-10-01
This prospective, longitudinal study with data collected at four time points investigated how maternal psychiatric symptoms, substance abuse and maternal intrusiveness in interaction were related to early child language skills. Three groups of mothers were recruited during pregnancy: One from residential treatment institutions for substance abuse (n = 18), one from psychiatric outpatient treatment (n = 22) and one from well-baby clinics (n = 30). Maternal substance abuse and anti-social and borderline personality traits were assessed during pregnancy, postpartum depression at 3 months, maternal intrusiveness in interaction at 12 months, and child language skills at 2 years. Results showed that the mothers in the substance abuse group had the lowest level of education, they were younger and they were more likely to be single mothers than the mothers in the two other groups. There was a significant difference in expressive language between children born to mothers with substance abuse problems and those born to comparison mothers, however not when controlling for maternal age, education and single parenthood. No group differences in receptive language skills were detected. Results further showed that maternal intrusiveness observed in mother-child interaction at 12 months was significantly related to child expressive language at 2 years, also when controlling for socio-demographic risk factors. This suggests that in addition to addressing substance abuse and psychiatric problems, there is a need for applying treatment models promoting sensitive caregiving, in order to enhance child expressive language skills. PMID:25300194
Irena Schneiderová
Full Text Available Shrews have rich vocal repertoires that include vocalizations within the human audible frequency range and ultrasonic vocalizations. Here, we recorded and analyzed in detail the acoustic structure of a vocalization with unclear functional significance that was spontaneously produced by 15 adult, captive Asian house shrews (Suncus murinus while they were lying motionless and resting in their nests. This vocalization was usually emitted repeatedly in a long series with regular intervals. It showed some structural variability; however, the shrews most frequently emitted a tonal, low-frequency vocalization with minimal frequency modulation and a low, non-vocal click that was clearly noticeable at its beginning. There was no effect of sex, but the acoustic structure of the analyzed vocalizations differed significantly between individual shrews. The encoded individuality was low, but it cannot be excluded that this individuality would allow discrimination of family members, i.e., a male and female with their young, collectively resting in a common nest. The question remains whether the Asian house shrews indeed perceive the presence of their mates, parents or young resting in a common nest via the resting-associated vocalization and whether they use it to discriminate among their family members. Additional studies are needed to explain the possible functional significance of resting-associated vocalizations emitted by captive Asian house shrews. Our study highlights that the acoustic communication of shrews is a relatively understudied topic, particularly considering that they are highly vocal mammals.
Complete text of publication follows. Structure of high latitude magnetospheric plasma domains and transverse magnetospheric currents is very important for the solution of the problem of large-scale magnetosphere-ionosphere interactions. Arguments showing the necessity to reanalyze the traditional approaches to such structure description are summarized taking into account the latest results of THEMIS project observations. Daytime compression of magnetic field lines and the existence of magnetic field minima far from the equatorial plane are taken into account. Dayside integral transverse currents at the geocentric distances 7-10Re are calculated in the suggestion of the validity of the condition of magnetostatic equilibrium and compared with nighttime transverse currents. It is shown that ordinary ring current has the high latitude continuation until geocentric distances ∼10-12Re. Isolated substorm expansion phase onset in such a case at the equatorial boundary of the auroral oval becomes the problem of ring current instability instead of ordinary suggestion on the tail current instability. The appearance of plasma motion across the most equatorial inverted V structure is selected as the main reason of bright arc formation and the increase of such motion as the reason of auroral brightening at the beginning of substorm expansion phase onset. The problem of the formation of large and middle scale electrostatic fields, Region 1 and Region 2 field-aligned current is analyzed. It is shown that the existence of definite boundary conditions leads to the possibility of the excitation of discrete number of modes, which are eigenfunctions of the problem with scales comparable with the transverse scale of the magnetosphere. Large-scale dawn-dusk electric field can be considered as the zero mode of plasma pressure instability. Such approach gives the possibility to overcome difficulties connected with the hypothesis of solar wind electric field penetration inside the
R. Roostaee
2012-01-01
Full Text Available Decisions in the real-world contexts are often made in the presence of multiple, conflicting, and incommensurate criteria. Multiobjective programming methods such as multiple objective linear programming (MOLP are techniques used to solve such multiple-criteria decision-making (MCDM problems. One of the first interactive procedures to solve MOLP is STEM method. In this paper we try to improve STEM method in a way that we search a point in reduced feasible region whose criterion vector is closest to positive ideal criterion vector and furthest to negative ideal criterion vector. Therefore the presented method tries to increase the rate of satisfactoriness of the obtained solution. Finally, a numerical example for illustration of the new method is given to clarify the main results developed in this paper.
Kristiansen, Jesper; Persson, Roger; Björk, Jonas; Albin, Maria; Jakobsson, Kristina; Östergren, Per-Olof; Ardö, Jonas
2011-01-01
To examine the risk of sleep problems associated with work stress (job strain, job demands, and decision authority), worries and pain and to investigate the synergistic interaction between these factors and traffic noise. Sleep problems and predictor variables were assessed in a cross-sectional public health survey with 12,093 respondents. Traffic noise levels were assessed using modelled A-weighted energy equivalent traffic sound levels at the residence. The risk of sleep problems was modell...
Pazouki Arman
2014-08-01
Full Text Available This work outlines a unified multi-threaded, multi-scale High Performance Computing (HPC approach for the direct numerical simulation of Fluid-Solid Interaction (FSI problems. The simulation algorithm relies on the extended Smoothed Particle Hydrodynamics (XSPH method, which approaches the fluid flow in a La-grangian framework consistent with the Lagrangian tracking of the solid phase. A general 3D rigid body dynamics and an Absolute Nodal Coordinate Formulation (ANCF are implemented to model rigid and flexible multibody dynamics. The two-way coupling of the fluid and solid phases is supported through use of Boundary Condition Enforcing (BCE markers that capture the fluid-solid coupling forces by enforcing a no-slip boundary condition. The solid-solid short range interaction, which has a crucial impact on the small-scale behavior of fluid-solid mixtures, is resolved via a lubrication force model. The collective system states are integrated in time using an explicit, multi-rate scheme. To alleviate the heavy computational load, the overall algorithm leverages parallel computing on Graphics Processing Unit (GPU cards. Performance and scaling analysis are provided for simulations scenarios involving one or multiple phases with up to tens of thousands of solid objects. The software implementation of the approach, called Chrono:Fluid, is part of the Chrono project and available as an open-source software.
The International Standard Problem (ISP) No. 30 on Molten Core Concrete Interaction (MCCI), which has been proposed by OECD-CSNI, was performed to improve the understanding of the physical phenomena involved and to assess the predictability of computer codes used for MCCI-analysis. The experiment selected for this ISP was the BETA V5.1 experiment conducted at the Kernforschungszentrum Karlsruhe. BETA V5.1 was designed to investigate the influence of high Zr-metal content in a steel melt interacting with a siliceous concrete crucible at high temperature. Since the computer codes used may be divided into thermal hydraulic codes and aerosol release codes, the submitted results can also be divided into these two groups. To separate the modelling capability of the codes and - as far as possible - the user influences the ISP was conducted as an open ISP, i.e. all necessary experimental results have been reported to the participants before performing the calculations. The major phenomena addressed in this ISP are the thermal-hydraulic behavior of metallic melt with high zirconium content, the zirconium chemistry, especially of the condensed phases, the aerosol release and the two dimensional concrete erosion
Scalco, Matthew D; Colder, Craig R; Hawk, Larry W; Read, Jennifer P; Wieczorek, William F; Lengua, Liliana J
2014-09-01
Externalizing problem behavior is a robust predictor of early adolescent substance use (SU); however, findings regarding internalizing problems have been mixed, suggesting that there may be important moderators of the relationship between internalizing problems and SU. The present study used a community sample (mean age was 12.1 at the first assessment, 55% women, 83% White) to test a longitudinal latent variable interaction structural equation model to examine whether externalizing problems moderated the relationship between internalizing problems and SU. Peer delinquency was tested as a mediator in the model and prior levels of the mediator and outcome were controlled at each wave to establish temporal precedence. Results suggested that (1) internalizing problems were protective against associating with deviant peers, but only at high levels of externalizing symptomatology, (2) higher levels of peer delinquency were associated with increases in SU, and (3) peer delinquency mediated the effect of the problem behavior interaction on SU. Our findings suggest that the impact of internalizing problems on peer delinquency and SU needs to be considered in the context of externalizing problems. Moreover, developmental models involving internalizing symptoms should consider that internalizing symptoms are generally protective against substance use in early adolescence. PMID:25134030
Dubois-Comtois, Karine; Bernier, Annie; Tarabulsy, George M; Cyr, Chantal; St-Laurent, Diane; Lanctôt, Anne-Sophie; St-Onge, Janie; Moss, Ellen; Béliveau, Marie-Julie
2015-10-01
This study investigated different environmental and contextual factors associated with maltreated children's adjustment in foster care. Participants included 83 children (52 boys), ages 1-7 years, and their foster caregivers. Quality of interaction with the foster caregiver was assessed from direct observation of a free-play situation; foster caregiver attachment state of mind and commitment toward the child were assessed using two interviews; disruptive behavior symptoms were reported by foster caregivers. Results showed that quality of interaction between foster caregivers and children were associated with behavior problems, such that higher-quality interactions were related to fewer externalizing and internalizing problems. Foster caregivers' state of mind and commitment were interrelated but not directly associated with behavior problems of foster children. Type of placement moderated the association between foster caregiver commitment and foster child behavior problems. Whereas greater foster caregiver commitment was associated with higher levels of adjustment for children in foster families (kin and non-kin), this was not the case in foster-to-adopt families. Finally, the associations between foster child behavior problems and history of maltreatment and placement related-risk conditions fell below significance after considering child age and quality of interaction with the foster caregiver. Findings underscore the crucial contribution of the foster caregiver-child relationship to fostering child adjustment and, thereby, have important implications for clinical services offered to this population. PMID:26187685
Rosales, Javier; Vicente, Santiago; Chamoso, Jose M.; Munez, David; Orrantia, Josetxu
2012-01-01
Word problem solving involves the construction of two different mental representations, namely, mathematical and situational. Although educational research in word problem solving has documented different kinds of instruction at these levels, less is known about how both representational levels are evoked during word problem solving in day-to-day…
Kuo, Thomas T. S; Holt, Jeremy W; Lee, Sabine
2010-01-01
This book provides a comprehensive overview of some key developments in the understanding of the nucleon-nucleon interaction and nuclear many-body theory. The main problems at the level of meson exchange physics have been solved, and we have an effective field theory using a phenomenological interaction pioneered by Achim Schwenk and Scott Bogner, which is nearly universally accepted as a unique low-momentum interaction that includes all experimental data to date. This understanding is based on a multi-step development in which different scientific insights and a wide range of physical and mat
The Graphical Unitary Group Approach (GUGA) was cast into an extraordinarily powerful form by restructuring the Hamiltonian in terms of loop types. This restructuring allows the adoption of the loop-driven formulation which illuminates vast numbers of previously unappreciated relationships between otherwise distinct Hamiltonian matrix elements. The theoretical/methodological contributions made here include the development of the loop-driven formula generation algorithm, a solution of the upper walk problem used to develop a loop breakdown algorithm, the restriction of configuration space employed to the multireference interacting space, and the restructuring of the Hamiltonian in terms of loop types. Several other developments are presented and discussed. Among these developments are the use of new segment coefficients, improvements in the loop-driven algorithm, implicit generation of loops wholly within the external space adapted within the framework of the loop-driven methodology, and comparisons of the diagonalization tape method to the direct method. It is also shown how it is possible to implement the GUGA method without the time-consuming full (m5) four-index transformation. A particularly promising new direction presented here involves the use of the GUGA methodology to obtain one-electron and two-electron density matrices. Once these are known, analytical gradients (first derivatives) of the CI potential energy are easily obtained. Several test calculations are examined in detail to illustrate the unique features of the method. Also included is a calculation on the asymmetric 21A' state of SO2 with 23,613 configurations to demonstrate methods for the diagonalization of very large matrices on a minicomputer. 6 figures, 6 tables
Nikolova Yuliya S
2012-11-01
Full Text Available Abstract Background Research into neural mechanisms of drug abuse risk has focused on the role of dysfunction in neural circuits for reward. In contrast, few studies have examined the role of dysfunction in neural circuits of threat in mediating drug abuse risk. Although typically regarded as a risk factor for mood and anxiety disorders, threat-related amygdala reactivity may serve as a protective factor against substance use disorders, particularly in individuals with exaggerated responsiveness to reward. Findings We used well-established neuroimaging paradigms to probe threat-related amygdala and reward-related ventral striatum reactivity in a sample of 200 young adult students from the ongoing Duke Neurogenetics Study. Recent life stress and problem drinking were assessed using self-report. We found a significant three-way interaction between threat-related amygdala reactivity, reward-related ventral striatum reactivity, and recent stress, wherein individuals with higher reward-related ventral striatum reactivity exhibit higher levels of problem drinking in the context of stress, but only if they also have lower threat-related amygdala reactivity. This three-way interaction predicted both contemporaneous problem drinking and problem drinking reported three-months later in a subset of participants. Conclusions These findings suggest complex interactions between stress and neural responsiveness to both threat and reward mediate problem drinking. Furthermore, they highlight a novel protective role for threat-related amygdala reactivity against drug use in individuals with high neural reactivity to reward.
Rendall, Drew; Owren, Michael J.; Weerts, Elise; Hienz, Robert D.
2004-01-01
This study quantifies sex differences in the acoustic structure of vowel-like grunt vocalizations in baboons (Papio spp.) and tests the basic perceptual discriminability of these differences to baboon listeners. Acoustic analyses were performed on 1028 grunts recorded from 27 adult baboons (11 males and 16 females) in southern Africa, focusing specifically on the fundamental frequency (F0) and formant frequencies. The mean F0 and the mean frequencies of the first three formants were all significantly lower in males than they were in females, more dramatically so for F0. Experiments using standard psychophysical procedures subsequently tested the discriminability of adult male and adult female grunts. After learning to discriminate the grunt of one male from that of one female, five baboon subjects subsequently generalized this discrimination both to new call tokens from the same individuals and to grunts from novel males and females. These results are discussed in the context of both the possible vocal anatomical basis for sex differences in call structure and the potential perceptual mechanisms involved in their processing by listeners, particularly as these relate to analogous issues in human speech production and perception.
Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD
, and demonstrated in public settings. We then describe INTERACT, a proposed research project that stages the robotic marionettes in a live performance. The interdisciplinary project brings humanities research to bear on scientific and technological inquiry, and culminates in the development a live......This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested...
D. Van der Giessen; T. Hollenstein; W.W., III Hale; H.M. Koot; W. Meeus; S. Branje
2014-01-01
Emotional variability reflects the ability to flexibly switch among a broad range of positive and negative emotions from moment-to-moment during interactions. Emotional variability during mother-adolescent conflict interactions is considered to be important for healthy socio-emotional functioning of
The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists such as...
Calcavecchia, Francesco
2016-01-01
We use the Shadow Wave Function formalism as a convenient model to study the fermion sign problem affecting all projector Quantum Monte Carlo methods in continuum space. We demonstrate that the efficiency of imaginary time projection algorithms decays exponentially with increasing number of particles and/or imaginary-time propagation. Moreover, we derive an analytical expression that connects the localization of the system with the magnitude of the sign problem, illustrating this prediction through some numerical results. Finally, we discuss the fermion sign problem computational complexity and methods for alleviating its severity.
R. G.G. Pessoa et al
2015-01-01
The present project is part of the course in biochemistry for biomedical undergraduate students of the Federal University of Pernambuco - UFPE, which comprises theoretical and practical classes and interactive seminars prepared by students on studied topics to supplement learning. The aim of this research was to encourage students to innovate their search for knowledge, presenting an interactive strategy to demonstrate the importance of carbohydrates, as well as other energy fuels, for underg...
Woodham, Luke A; Ellaway, Rachel H.; Round, Jonathan; Vaughan, Sophie; Poulton, Terry; Zary, Nabil
2015-01-01
Background The impact of the use of video resources in primarily paper-based problem-based learning (PBL) settings has been widely explored. Although it can provide many benefits, the use of video can also hamper the critical thinking of learners in contexts where learners are developing clinical reasoning. However, the use of video has not been explored in the context of interactive virtual patients for PBL. Objective A pilot study was conducted to explore how undergraduate medical students ...
Muha, Boris; Canic, Suncica
2012-01-01
We study a nonlinear, unsteady, moving boundary, fluid-structure interaction (FSI) problem arising in modeling blood flow through elastic and viscoelastic arteries. The fluid flow, which is driven by the time-dependent pressure data, is governed by 2D incompressible Navier-Stokes equations, while the elastodynamics of the cylindrical wall is modeled by the 1D cylindrical Koiter shell model. Two cases are considered: the linearly viscoelastic and the linearly elastic Koiter shell. The fluid an...
Albina G. Dolgan
2016-06-01
Full Text Available Introduction: nowadays Russian people are proactively seeking cooperation with the Asian Pacific Rim. Considering this the author has developed a curricular for institutions of higher learning training students in intercultural business interaction in this region within such disciplines as “Foreign language” and “Professional foreign language”. Materials and Methods: the author puts forward a comprehensive test as a way to define the level of students’ preparedness for business interaction within the Asian Pacific Rim, to test that they understand what they learn and to identify qualitative indicators attending to acquisition of content, and development of communicative and linguistic competences, as well as such necessary characteristics as pragmatism and tolerance. The comprehensive test elaboration was based on A. A. Verbitskiy and E. E. Kreslavskaya’s method of assessing the students’ understanding of meaning and significance of information. Results: drawing upon ideas of researchers studying intercultural communication, East Asian peoples’ values, region’s social, cultural and economic problems, the author proposes some special direction for the learning process – it should orient the Far Eastern students to take into consideration values, behaviours, mental and cultural specifics of partners from China, Korea, Japan and other neighboring countries in the business interaction. It is impossible to subdivide such interaction into professional and social spheres, so the author has chosen a problem situation to be a basic form for organising the learning process. The prob- lem situations of the social and professional character have been taken from East Asia business practices. Discussion and Conclusions: to solve the problem how to check students’ understanding of the learning information, the author has developed a comprehensive test where a problem situation is also used. The paper’s objective is to show how these
Ş. Özdemir
2013-07-01
Full Text Available Mathematics is an important discipline, providing crucial tools, such as problem solving, to improve our cognitive abilities. In order to solve a problem, it is better to envision and represent through multiple means. Multiple representations can help a person to redefine a problem with his/her own words in that envisioning process. Dynamic and Interactive Mathematics Learning Environments (DIMLE, allow multiple representations in mathematics and therefore provide opportunities to explore, to explain, and to model (Karadag & McDougall, 2009 mathematical subjects or concepts. The goal of this study is to explore the effect of multiple representations on perceptions of elementary mathematics pre-service teachers in problem solving process. Hence, ten representations, which dynamically represent a word problem, are created by using one of the DIMLE, GeoGebra. The sample group consists of elementary mathematics pre-service teachers (n=17. In order to precisely analyze the data, which are gathered from sample group, quan-qual mix method was used. Consequently, the use of multiple representations, which were prepared by DIMLE, cause to a mental demand for the other mathematical concepts except for understanding and solving a problem.
A quark-model NN interaction and its application to the three-nucleon and nuclear-matter problems
Baryon-baryon interactions of the complete baryon octet (B8) are investigated in a unified framework of the (3q)-(3q) resonating-group method, which employs the spin-flavor SU6 quark-model were functions. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon interaction. Some characteristic features of the B8B8 interactions predicted by the most recent model fss2 are discussed. The nucleon-nucleon sector of this quark-model potential is used to calculate G-matrices for nuclear and neutron matter, and to solve the Faddeev equation of the three-nucleon bound state. The calculated binding energy for 3H is the closest to the experiment among many results obtained by detailed Faddeev calculations employing modern realistic nucleon-nucleon potentials. (author)
Belt, Ritva; Punamaki, Raija-Leena
2007-01-01
In this article we present a novel method of outpatient care: brief, dynamic mother-infant group psychotherapy with mothers who have substance use problems. In this therapy, substance abuse treatment is part of mental health and parenting interventions. The focus is on preventing disturbance in the mother-infant relationship in this high-risk…
Anatolii I. Zadorozhnyi; Igor V. Kolesnikov
2011-01-01
In the article the axially symmetric mixed problem of heat conduction for a system «a wheel-disk brake» is considered. The solution is obtained by Fox method of average and method of joining of the solutions on a demarcation line between the boundary conditions.
Anatolii I. Zadorozhnyi
2011-05-01
Full Text Available In the article the axially symmetric mixed problem of heat conduction for a system «a wheel-disk brake» is considered. The solution is obtained by Fox method of average and method of joining of the solutions on a demarcation line between the boundary conditions.
George, Carrie; Herman, Keith C.; Ostrander, Rick
2006-01-01
Prior studies have found remarkable similarity in the family characteristics across a wide range of child psychopathologies. This study investigated the unique relationships between symptoms of depression, conduct problems/aggression, and inattention/hyperactivity and characteristics of the family environment. Parents and teachers completed…
da Silva, André Constantino; Freire, Fernanda Maria Pereira; de Arruda, Alan Victor Pereira; da Rocha, Heloísa Vieira
2013-01-01
e-Learning environments offer content, such text, audio, video, animations, using the Web infrastructure and they are designed to users interacting with keyboard, mouse and a medium-sized screen. Mobile devices, such as smartphones and tablets, have enough computation power to render Web pages, allowing browsing the Internet and access e-Learning…
Yelovich, Mary-Clair
2016-08-01
Patient non-adherence is a common and important concern in clinical medicine. Some cases of patient non-adherence are cases in which the patient disagrees with the physician's recommended treatment based on particular reasons. Drawing upon science and technology studies literature, specifically the discussion by Collins and Evans and Wynne of how best to understand scientific controversies, I relate their ideas to the analogous conflict that may occur within a clinical interaction. I draw upon their recognition of the importance of contributory expertise and interactional expertise in providing legitimate knowledge. I also draw upon Wynne's idea of the 'negotiation of meanings' as an important element of the clinical interaction. To resolve potential conflicts between patient and physician before they develop into 'non-adherence', I propose the implementation of a new epistemological framework that recognizes legitimate knowledge offered by the patient as well as the physician. By situating this patient expertise framework within the paradigm of patient-centred medicine, and by assuming the goal of medical treatment to be treatment of suffering, patient expertise becomes centralized as a means of determining the nature of patient suffering. Two aspects of the patient's tacit knowledge - the body aspect and the meaning aspect - both of which are context-dependent and directly accessible only to the patient, are thus recognized as knowledge essential to the success of the interaction. The physician's role becomes that of both medical expert and possessor of 'interactional expertise', by which the physician recognizes and includes patient expertise in the treatment decision. By recognizing and incorporating the negotiation of meanings into the development of a treatment plan, this epistemological model of patient expertise should prevent cases of non-adherence based on disagreement. PMID:27189520
Andrei Halanay
2013-07-01
Full Text Available In the present paper, we use a penalization of the Stokes equationin order to obtain approximate solutions in a larger domain includingthe domain occupied by the structure. The coefficients of the fluid problem, excepting the penalizing term, are constant and independent of the deformation of the structure, which represents an advantage of this approach. Subtracting the structure equations from the fictitious fluid equations in the structure domain and using the Green's formula, we obtain a weak formulation where the continuity of the stress at the interface does not appear explicitly. This is a second advantage of this model, because the computation of the stress at the fluid-structure interface is not easy from the theoretical point of view as well as for the numerical approximation. This problem is a free boundary problem and a fundamental difficulty is to find the free interface between the fluid and the structure, which is unknown and has to be identified together with the solution of the given system of equations.
Morchio, G
2014-01-01
The electrodynamics of heavy charged particles is studied through a model of classical particles with Coulomb interaction and standard interaction with photons. The use of a Dollard strategy allows for the existence of the Moller operators and the identification of the asymptotic dynamics as a group, satisfying the ordinary interpolation formula; the S-matrix commutes with the asymptotic dynamics and exhibits an explicit factorization of all the infrared divergences. In the second quantized version, the asymptotic limit of the Heisenberg charged fields are obtained as strong limits of modified Lehmann-Symanzik-Zimmermann formulas, the corrections being explicitly given by a Coulomb phase operator and by an exponential of the photon field. The asymptotic field algebras have the structure of a semidirect product and the Hamiltonian is the sum of the two free Hamiltonians.
Solution to a 3D atom–laser interaction problem by sine-DVR and split-operator propagator
Highlights: • We present a 3D quantum approach for studying the atom–laser interaction. • Sine-DVR and split-operator propagator are used for economizing computational time. • Our calculated electron spectrum has good agreement with experimental result. • The ATI spectra have studied in linearly and circularly polarized lights. - Abstract: We present a three-dimensional quantum approach for exploring atom–laser interaction based on solution of time-dependent Schrödinger equation. And the numerical results are achieved with sine-DVR (discrete variable representation) and split-operator propagator in the length gauge. Applications of the present theoretical approach have been illustrated in the calculations of the photoelectron features for argon in either linearly or circularly polarized laser field. Our calculated photoelectron spectra have good agreement with experimental results in both of the two polarization laser fields, and the features of above threshold ionization spectra are investigated
The report contains an introduction to the physics of the lepton-nucleon scattering in the first three resonance regions, which correspond to the range of invariant masses W from 1.1 to ∼ 2 GeV. It is emphasized, that large uncertainty in the determination of the limits of the validity of the perturbative QCD is related with poor understanding of the evolution of a resonance structure as a function of W and Q2. The study of the VCS reaction and of its W dependence relatively to the π0 electroproduction can have a number of advantages in pursuing a problem of the resonance structure evolution. (author)
Maj-Lis Follér
2001-01-01
Full Text Available This article deals with methodological issues and how to link global processes - social and ecological - with environmental changes and human health in local communities. The discussion concerns how interdisciplinary approaches can help us find tools to develop new knowledge. Scientific knowledge and local knowledge are not seen as opposite epistemological forms, but as socially and culturally constructed. Power and social legitimacy have to be included when analyzing how to deal with the interaction between global processes and local environmental change and the health/disease interface.
Jiang, Xikai; Zhao, Xujun; Qin, Jian; Karpeev, Dmitry; Hernandez-Ortiz, Juan; de Pablo, Juan; Heinonen, Olle
2016-01-01
Large classes of materials systems in physics and engineering are governed by magnetic and electrostatic interactions. Continuum or mesoscale descriptions of such systems can be cast in terms of integral equations, whose direct computational evaluation requires O(N^2) operations, where N is the number of unknowns. Such a scaling, which arises from the many-body nature of the relevant Green's function, has precluded wide-spread adoption of integral methods for solution of large-scale scientific and engineering problems. In this work, a parallel computational approach is presented that relies on using scalable open source libraries and utilizes a kernel-independent Fast Multipole Method to evaluate the integrals in O(N) operations, with O(N) memory cost, thereby substantially improving the scalability and efficiency of computational integral methods. We demonstrate the accuracy, efficiency, and scalability of our approach in the contest of two examples. In the first, we solve a boundary value problem for a ferr...
Pasalich, Dave S; Dadds, Mark R; Hawes, David J
2014-11-30
Callous-unemotional (CU) traits and autism spectrum disorders (ASD) symptoms are characterized by problems in empathy; however, these behavioral features are rarely examined together in children with conduct problems. This study investigated additive and interactive effects of CU traits and ASD symptoms in relation to cognitive and affective empathy in a non-ASD clinic-referred sample. Participants were 134 children aged 3 to 9 years (M=5.60; 79% boys) with oppositional defiant/conduct disorder, and their parents. Clinicians, teachers, and parents reported on dimensions of child behavior, and parental reports of family dysfunction and direct observations of parental warmth/responsiveness assessed quality of family relationships. Results from multiple regression analysis showed that, over and above the effects of child conduct problem severity and quality of family relationships, both ASD symptoms and CU traits were uniquely associated with deficits in cognitive empathy. Moreover, CU traits demonstrated an independent association with affective empathy, and this relationship was moderated by ASD symptoms. That is, there was a stronger negative association between CU traits and affective empathy at higher versus lower levels of ASD symptoms. These findings suggest including both CU traits and ASD-related social impairments in models delineating the atypical development of empathy in children with conduct problems. PMID:25015711
Trout, Joseph; Bland, Jared
2013-03-01
In this pilot project, one hour of lecture time was replaced with one hour of in-class assignments, which groups of students collaborated on. These in-class assignments consisted of problems or projects selected for the calculus-based introductory physics students The first problem was at a level of difficulty that the majority of the students could complete with a small to moderate amount of difficulty. Each successive problem was increasingly more difficult, the last problem being having a level of difficulty that was beyond the capabilities of the majority of the students and required some instructor intervention. The students were free to choose their own groups. Students were encouraged to interact and help each other understand. The success of the in-class exercises were measured using pre-tests and post-tests. The pre-test and post-test were completed by each student independently. Statistics were also compiled on each student's attendance record and the amount of time spent reading and studying, as reported by the student. Statistics were also completed on the student responses when asked if they had sufficient time to complete the pre-test and post-test and if they would have completed the test with the correct answers if they had more time. The pre-tests and post-tests were not used in the computation of the grades of the students.
Pierce, S. A.
2014-12-01
Geosciences are becoming increasingly data intensive, particularly in relation to sustainability problems, which are multi-dimensional, weakly structured and characterized by high levels of uncertainty. In the case of complex resource management problems, the challenge is to extract meaningful information from data and make sense of it. Simultaneously, scientific knowledge alone is insufficient to change practice. Creating tools, and group decision support processes for end users to interact with data are key challenges to transforming science-based information into actionable knowledge. The ENCOMPASS project began as a multi-year case study in the Atacama Desert of Chile to design and implement a knowledge transfer model for energy-water-mining conflicts in the region. ENCOMPASS combines the use of cyberinfrastructure (CI), automated data collection, interactive interfaces for dynamic decision support, and participatory modelling to support social learning. A pilot version of the ENCOMPASS CI uses open source systems and serves as a structure to integrate and store multiple forms of data and knowledge, such as DEM, meteorological, water quality, geomicrobiological, energy demand, and groundwater models. In the case study, informatics and data fusion needs related to scientific uncertainty around deep groundwater flowpaths and energy-water connections. Users may upload data from field sites with handheld devices or desktops. Once uploaded, data assets are accessible for a variety of uses. To address multi-attributed decision problems in the Atacama region a standalone application with touch-enabled interfaces was created to improve real-time interactions with datasets by groups. The tool was used to merge datasets from the ENCOMPASS CI to support exploration among alternatives and build shared understanding among stakeholders. To date, the project has increased technical capacity among stakeholders, resulted in the creation of both for-profit and non
Holzhausen, K. P.; Gaertner, K. P.
1985-01-01
A significant problem concerning the integration of display and switching functions is related to the fact that numerous informative data which have to be processed by man must be read from only a few display devices. A satisfactory ergonomic design of integrated display devices and keyboards is in many cases difficult, because not all functions which can be displayed and selected are simultaneously available. A technical solution which provides an integration of display and functional elements on the basis of the highest flexibility is obtained by using a cathode ray tube with a touch-sensitive screen. The employment of an integrated data input/output system is demonstrated for the cases of onboard and ground-based flight control. Ergonomic studies conducted to investigate the suitability of an employment of touch-sensitive screens are also discussed.
A series of bow shock studies conducted for the purpose of investigating the interaction between the solar wind and the terrestrial planets is presented. Toward this end appropriate modeling techniques have been developed and applied to the bow wave observations at Venus, Earth, and Mars. For Mercury the measurements are so few in number that no accurate determination of shock shape was deemed possible. Flow solutions generated using the observed bow wave surface as a boundary condition in a single fluid variable obstacle shape gasdynamic model produced excellent fits to the measured width and shape of the earth's magnetosheath. This result and the observed ordering of shock shape and position by upstream sonic Mach number provide strong support for the validity of the gasdynamic approximation. At Mercury the application of earth type models to the individual Mariner 10 boundry crossings has led to the determination of an effective planetary magnetic moment of 6+-2 x 1022 G-cm3. Consistent with the presence of a small terrestrial style magnetosphere, southward interplanetary magnetic fields were found to significantly reduce the solar wind stand-off distance most probably through the effects of dayside magnetic reconnection. For Venus the low altitude solar wind flow field derived from gasdynamic modeling of bow shock location and shape indicates that a fraction of the incident streamlines are absorbed by the neutral atmosphere near the ionopause; approximately 1% and 8%, respectively, in the solar maximum Pioneer Venus and solar minimum Venera measurements. Accordingly, it appears that cometary processes must be included in model calculations of the solar wind flow about Venus. At Mars the moderate height of the gasdynamic solar wind-obstacle interface and the weakness of the Martian ionosphere/atmosphere are found to be incompatible with a Venus type interaction
R. G.G. Pessoa et al
2015-08-01
Full Text Available The present project is part of the course in biochemistry for biomedical undergraduate students of the Federal University of Pernambuco - UFPE, which comprises theoretical and practical classes and interactive seminars prepared by students on studied topics to supplement learning. The aim of this research was to encourage students to innovate their search for knowledge, presenting an interactive strategy to demonstrate the importance of carbohydrates, as well as other energy fuels, for undergraduates students attending classes of biochemistry at the first semester at the university, in order to clarify the importance of maintaining a healthy way of life. The methodology used was a field research, documented in videos in which the opinions of a few people were registered in different places, such as in a fast-food restaurant, on the importance of carbohydrates. Records acquired were associated with a slide presentation on the subject, based on scientific books and articles, which were presented to the students of the discipline. It was also developed a dynamic to illustrate the consumption of carbohydrates in daily life and in different situations. After the project exhibition, a review of the research was conducted to the audience to express innovations or additions to their pre-existing concepts, on consumption of carbohydrates. The results of our work were very promising and the main goal of the project was achieved, since 88.2% of the respondents said there was an improvement in their knowledge, both theoretical and practical, on the subject, while only 11.8% reported no improvement at all. In conclusion, there was a greater involvement of students during the presentation of the subject and a higher participation during the group dynamic on the consumption of carbohydrates.
The disagreement of the predicted abundance of primordial $^{7}$Li with the observed abundance is a longstanding problem in Big Bang Nucleosynthesis (BBN) theory (“Primordial $^{7}$Li problem”). While BBN theory correctly predicts the relative abundances of $^{2}$H/$^{1}$H, $^{3}$He/$^{1}$H and $^{4}$He/$^{1}$H (that vary over four orders of magnitudes), but it over-predicts the relative abundance of primordial $^{7}$Li/$^{1}$H by a factor of approximately 3-4 larger than observed (approximately 4-5$\\sigma$ discrepancy). Primordial $^{7}$Li is destroyed during the first 15 minutes primarily via the $^{7}$Li(p,$\\alpha$) reaction. Hence most of the primordial $^7$Li is predicted as the result of the (later when atoms are formed) electron capture $\\beta$-decay of the primordial $^{7}$Be that is produced primarily in the $^{3}$He($\\alpha$,$\\gamma$) )$^{7}$Be reaction. We propose to investigate the direct destruction of $^{7}$Be during (the first 15 minutes of) BBN via the $^{7}$Be(n,$\\alpha$) reaction to ch...
Smolyakov, Mikhail N.; Volobuev, Igor P.
2016-01-01
In this paper we examine, from the purely theoretical point of view and in a model-independent way, the case, when matter, gauge and Higgs fields are allowed to propagate in the bulk of five-dimensional brane world models with compact extra dimension, and the Standard Model fields and their interactions are supposed to be reproduced by the corresponding zero Kaluza-Klein modes. An unexpected result is that in order to avoid possible pathological behavior in the fermion sector, it is necessary to impose constraints on the fermion field Lagrangian. In the case when the fermion zero modes are supposed to be localized at one of the branes, these constraints imply an additional relation between the vacuum profile of the Higgs field and the form of the background metric. Moreover, this relation between the vacuum profile of the Higgs field and the form of the background metric results in the exact reproduction of the gauge boson and fermion sectors of the Standard Model by the corresponding zero mode four-dimensional effective theory in all the physically relevant cases, allowed by the absence of pathologies. Meanwhile, deviations from these conditions can lead either back to pathological behavior in the fermion sector or to a variance between the resulting zero mode four-dimensional effective theory and the Standard Model, which, depending on the model at hand, may, in principle, result in constraints putting the theory out of the reach of the present day experiments.
Jiang, Xikai; Li, Jiyuan; Zhao, Xujun; Qin, Jian; Karpeev, Dmitry; Hernandez-Ortiz, Juan; de Pablo, Juan J.; Heinonen, Olle
2016-08-01
Large classes of materials systems in physics and engineering are governed by magnetic and electrostatic interactions. Continuum or mesoscale descriptions of such systems can be cast in terms of integral equations, whose direct computational evaluation requires O(N2) operations, where N is the number of unknowns. Such a scaling, which arises from the many-body nature of the relevant Green's function, has precluded wide-spread adoption of integral methods for solution of large-scale scientific and engineering problems. In this work, a parallel computational approach is presented that relies on using scalable open source libraries and utilizes a kernel-independent Fast Multipole Method (FMM) to evaluate the integrals in O(N) operations, with O(N) memory cost, thereby substantially improving the scalability and efficiency of computational integral methods. We demonstrate the accuracy, efficiency, and scalability of our approach in the context of two examples. In the first, we solve a boundary value problem for a ferroelectric/ferromagnetic volume in free space. In the second, we solve an electrostatic problem involving polarizable dielectric bodies in an unbounded dielectric medium. The results from these test cases show that our proposed parallel approach, which is built on a kernel-independent FMM, can enable highly efficient and accurate simulations and allow for considerable flexibility in a broad range of applications.
Kawasaki Masahiro
2012-02-01
Full Text Available The plateau of 7Li abundance as a function of the iron abundance by spectroscopic observations of metal-poor halo stars (MPHSs indicates its primordial origin. The observed abundance levels are about a factor of three smaller than the primordial 7Li abundance predicted in the standard Big Bang Nucleosynthesis (BBN model. This discrepancy might originate from exotic particle and nuclear processes operating in BBN epoch. Some particle models include heavy (m >> 1 GeV long-lived colored particles which would be confined inside exotic heavy hadrons, i.e., strongly interacting massive particles (SIMPs. We have found reactions which destroy 7Be and 7Li during BBN in the scenario of BBN catalyzed by a long-lived sub-strongly interacting massive particle (sub-SIMP, X. The reactions are non radiative X captures of 7 Be and 7Li which can be operative if the X particle interacts with nuclei strongly enough to drive 7 Be destruction but not strongly enough to form a bound state with 4 He of relative angular momentum L = 1. We suggest that 7Li problem can be solved as a result of a new process beyond the standard model through which the observable signature was left on the primordial Li abundance.
Full text: A nonperturbative character of QCD at low and intermediate energies generates serious mathematical difficulties in describing the dynamics of hadron-hadron interactions in terms quark-gluon degrees of freedom. Therefore much effort has gone in past years into developing QCD-motivated approaches that formulate the theory of strong interaction in terms of hadron degrees of freedom. The path-integral technique together with idea of spontaneous chiral-symmetry breaking leads to Effective Field Theory (EFT) [1]. Unfortunately EFT can be applied to description of hadron-hadron interactions only at very low energies. On the other hand, meson theories of nuclear forces have long since been used to describe the properties of nucleon systems and scattering processes. Now it is not quite clear, up to what distances the meson-exchange pattern of nuclear forces is valid. Recently the new relativistic approach to the problem of constructing effective hadron-hadron interaction operators has been proposed [2-4] on the basis of analytic S-matrix theory and Gelfand-Levitan-Marchenko-Martin methods for solving the inverse quantum scattering problem. In this approach effective potential is defined as a local operator in a partial-wave equation of the quasipotential type such that it generates on-shell relativistic (Feynman) scattering amplitude that has required discontinuities at dynamical cuts. The discontinuities of partial-wave amplitudes are determined by model-independent quantities (renormalized vertex constants and amplitudes of subprocesses involving on-mass-shell particles off the physical region) and can be calculated by methods of relativistic quantum field theory within various dynamical approaches. In particular, EFT can be used to calculate the discontinuities across dynamical-cut segments closest to the physical region. In [2-4] we have examined the basic features of the proposed approach. Attention has been given primarily to analyzing the new mechanism of
Zheng Guo
2010-01-01
Full Text Available A new virtual baffle methodology is implemented to solve contact/detach problem which is often encountered in fluid and structure interaction simulations while using dynamic grids technique. The algorithm is based on tetrahedral unstructured grid, and a zero thickness baffle face is generated between actually contacted two objects. In computation process, this baffle face is divided into two parts representing convective and blocked area, respectively; the area of each part is calculated according to the actual displacement between the two objects. Convective part in a baffle face is treated as inner interface between cells, and on blocked part wall boundary condition is applied; so convective and blocking effect can be achieved on a single baffle face. This methodology can simulate real detaching process starting from contact, that is, zero displacement, while it has no restriction to minimum grid cell size. The methodology is then applied in modeling of a complicated safety valve opening process, involving multidisciplinary fluid and structure interaction and dynamic grids. The results agree well with experimental data, which proves that the virtual baffle method is successful.
Helga Loos
2004-12-01
Full Text Available Partindo de uma perspectiva construtivista e interacionista, pesquisadores têm apontado o conflito sócio-cognitivo como situação que favorece o desenvolvimento cognitivo em estudantes que resolvem problemas conjuntamente. Com base no pressuposto de que elementos afetivos estão interligados aos sociais e cognitivos, o estudo teve por objetivo observar como oito duplas de estudantes de sexta e sétima séries gerenciavam, simultaneamente, a busca de solução para quatro problemas algébricos, a relação interpessoal e a ansiedade gerada pelas dificuldades eventualmente encontradas. As sessões foram videografadas e analisadas qualitativamente. Observou-se que: (1 todas as duplas manifestaram ansiedade relacionada às dificuldades da tarefa; (2 uma boa interação facilitou o gerenciamento dessa ansiedade; (3 uma má interação piorou o desempenho, sendo fonte adicional de ansiedade e desencorajando o desencadeamento de conflitos sócio-cognitivos; (4 uma boa interação e um gerenciamento adequado da ansiedade não puderam garantir um bom desempenho na tarefa quando, a pelo menos um dos participantes, faltavam os requisitos cognitivos mínimos para dominá-la.From a constructionist and interactionist perspective, researchers have shown that the socio-cognitive conflict leads to a cognitive development by students in solving-problem tasks in small groups. Based on the paradigm that affective factors are interconnected to the social and cognitive ones, this study aimed to observe sixteen 6th and 7th grade students in working in pairs, how they manage simultaneously: the solution search to four given algebraic problems, the interpersonal relationship and the anxiety generated by the difficulties eventually found. The sessions were recorded in video and qualitatively analyzed. It was observed that: (1 all groups manifested anxiety related to the difficulties of the task; (2 good interactions facilitated anxiety management; (3 bad interactions