Problem Solving with General Semantics.
Hewson, David
1996-01-01
Discusses how to use general semantics formulations to improve problem solving at home or at work--methods come from the areas of artificial intelligence/computer science, engineering, operations research, and psychology. (PA)
Problem solving and inference mechanisms
Energy Technology Data Exchange (ETDEWEB)
Furukawa, K; Nakajima, R; Yonezawa, A; Goto, S; Aoyama, A
1982-01-01
The heart of the fifth generation computer will be powerful mechanisms for problem solving and inference. A deduction-oriented language is to be designed, which will form the core of the whole computing system. The language is based on predicate logic with the extended features of structuring facilities, meta structures and relational data base interfaces. Parallel computation mechanisms and specialized hardware architectures are being investigated to make possible efficient realization of the language features. The project includes research into an intelligent programming system, a knowledge representation language and system, and a meta inference system to be built on the core. 30 references.
Using a general problem-solving strategy to promote transfer.
Youssef-Shalala, Amina; Ayres, Paul; Schubert, Carina; Sweller, John
2014-09-01
Cognitive load theory was used to hypothesize that a general problem-solving strategy based on a make-as-many-moves-as-possible heuristic could facilitate problem solutions for transfer problems. In four experiments, school students were required to learn about a topic through practice with a general problem-solving strategy, through a conventional problem solving strategy or by studying worked examples. In Experiments 1 and 2 using junior high school students learning geometry, low knowledge students in the general problem-solving group scored significantly higher on near or far transfer tests than the conventional problem-solving group. In Experiment 3, an advantage for a general problem-solving group over a group presented worked examples was obtained on far transfer tests using the same curriculum materials, again presented to junior high school students. No differences between conditions were found in Experiments 1, 2, or 3 using test problems similar to the acquisition problems. Experiment 4 used senior high school students studying economics and found the general problem-solving group scored significantly higher than the conventional problem-solving group on both similar and transfer tests. It was concluded that the general problem-solving strategy was helpful for novices, but not for students that had access to domain-specific knowledge. PsycINFO Database Record (c) 2014 APA, all rights reserved.
How to solve path integrals in quantum mechanics
International Nuclear Information System (INIS)
Grosche, C.
1994-10-01
A systematic classification of Feynman path integrals in quantum mechanics is presented and a table of solvable path integrals is given which reflects the progress made during the last 15 years, including, of course, the main contributions since the invention of the path integral by Feynman in 1942. An outline of the general theory is given which will serve as a quick reference for solving path integrals. Explicit formulae for the so-called basic path integrals are presented on which our general scheme to classify and calculate path integrals in quantum mechanics is based. (orig.)
Problem solving therapy - use and effectiveness in general practice.
Pierce, David
2012-09-01
Problem solving therapy (PST) is one of the focused psychological strategies supported by Medicare for use by appropriately trained general practitioners. This article reviews the evidence base for PST and its use in the general practice setting. Problem solving therapy involves patients learning or reactivating problem solving skills. These skills can then be applied to specific life problems associated with psychological and somatic symptoms. Problem solving therapy is suitable for use in general practice for patients experiencing common mental health conditions and has been shown to be as effective in the treatment of depression as antidepressants. Problem solving therapy involves a series of sequential stages. The clinician assists the patient to develop new empowering skills, and then supports them to work through the stages of therapy to determine and implement the solution selected by the patient. Many experienced GPs will identify their own existing problem solving skills. Learning about PST may involve refining and focusing these skills.
Generalized classical mechanics
International Nuclear Information System (INIS)
De Leon, M.; Rodrigues, P.R.
1985-01-01
The geometrical study of Classical Mechanics shows that the Hamiltonian (respectively, Lagrangian) formalism may be characterized by intrinsical structures canonically defined on the cotangent (respectively, tangent) bundle of a differentiable manifold. A generalized formalism for higher order Lagrangians is developed. Then the Hamiltonian form of the theory is developed. Finally, the Poisson brackets are defined and the conditions under which a mapping is a canonical transformation are studied. The Hamilton-Jacobi equation for this type of mechanics is established. (Auth.)
Students' Epistemological Framing in Quantum Mechanics Problem Solving
Modir, Bahar; Thompson, John D.; Sayre, Eleanor C.
2017-01-01
Students' difficulties in quantum mechanics may be the result of unproductive framing and not a fundamental inability to solve the problems or misconceptions about physics content. We observed groups of students solving quantum mechanics problems in an upper-division physics course. Using the lens of epistemological framing, we investigated four…
Solving problems in fluid mechanics. Vol. 1
International Nuclear Information System (INIS)
Douglas, J.F.
1986-01-01
Fluid mechanics is that part of applied mechanics concerned with the statics and dynamics of liquids and gases. The presentation is in a pedagogically sound question-and-answer format, which includes many worked examples preceding the exercises. This book which assumes only an elementary knowledge of mathematics and mechanics, offers a clear exposition of topics including hydrostatics, fluid pressure and the stability of floating bodies, fluid motion, flow measurement, pipelines, open channel flow, and fluid friction
Solved Problems in Quantum and Statistical Mechanics
Cini, Michele; Sbragaglia, Mauro
2012-01-01
This work arises from our teaching this subject during many years. The vast majority of these exercises are the exams we gave to our students in this period. We carefully selected the subjects of the exercises to cover all the material which is most needed and which is treated in the most well known texts on these subjects. Each exercise is carefully solved in full details, explaining the theory behind the solution with particular care for those issues that, from our experience, are found most difficult from the average student. Indeed, several exercises are designed to throw light on aspects of the theory that, for one reason or another, are usually neglected with the result to make the students feel uneasy about them. In fact most students get acquainted just with the more common manipulations, which are illustrated by many examples in textbooks. Our exercises never require extensive calculations but tend to be somewhat unusual and force the solver to think about the problem starting from the ...
Innovation and problem solving: a review of common mechanisms.
Griffin, Andrea S; Guez, David
2014-11-01
Behavioural innovations have become central to our thinking about how animals adjust to changing environments. It is now well established that animals vary in their ability to innovate, but understanding why remains a challenge. This is because innovations are rare, so studying innovation requires alternative experimental assays that create opportunities for animals to express their ability to invent new behaviours, or use pre-existing ones in new contexts. Problem solving of extractive foraging tasks has been put forward as a suitable experimental assay. We review the rapidly expanding literature on problem solving of extractive foraging tasks in order to better understand to what extent the processes underpinning problem solving, and the factors influencing problem solving, are in line with those predicted, and found, to underpin and influence innovation in the wild. Our aim is to determine whether problem solving can be used as an experimental proxy of innovation. We find that in most respects, problem solving is determined by the same underpinning mechanisms, and is influenced by the same factors, as those predicted to underpin, and to influence, innovation. We conclude that problem solving is a valid experimental assay for studying innovation, propose a conceptual model of problem solving in which motor diversity plays a more central role than has been considered to date, and provide recommendations for future research using problem solving to investigate innovation. This article is part of a Special Issue entitled: Cognition in the wild. Copyright © 2014 Elsevier B.V. All rights reserved.
Quantum mechanics from general relativity
International Nuclear Information System (INIS)
Sachs, M.
1986-01-01
A generalization of quantum mechanics is demonstrated in the context of general relativity, following from a generally covariant field theory of inertia. Nonrelativistically, the formalism corresponds with linear quantum mechanics. In the limit of special relativity, nonlinearity remains and several new features are derived: (1) Particle-antiparticle pairs do not annihilate; an exact bound state solution is derived corresponding with all experimental facts about annihilation/creation - which, in approximation, gives the blackbody radiation spectrum for a sea of such pairs. (2) A result is proven, without approximation, that is physically equivalent to the Pauli exclusion principle - which, in linear approximation, gives the totally antisymmetrised many-body wave function and Fermi-Dirac statistics. (3) The hydrogen spectrum is derived, including the Lamb shifts, in agreement with experiment; new results are found for high energy electron-proton scattering. (4) Finally, several applications to the elementary particle domain are demonstrated, in agreement with results from experimental high energy physics. (Auth.)
Tool use and mechanical problem solving in apraxia.
Goldenberg, G; Hagmann, S
1998-07-01
Moorlaas (1928) proposed that apraxic patients can identify objects and can remember the purpose they have been made for but do not know the way in which they must be used to achieve that purpose. Knowledge about the use of objects and tools can have two sources: It can be based on retrieval of instructions of use from semantic memory or on a direct inference of function from structure. The ability to infer function from structure enables subjects to use unfamiliar tools and to detect alternative uses of familiar tools. It is the basis of mechanical problem solving. The purpose of the present study was to analyze retrieval of instruction of use, mechanical problem solving, and actual tool use in patients with apraxia due to circumscribed lesions of the left hemisphere. For assessing mechanical problem solving we developed a test of selection and application of novel tools. Access to instruction of use was tested by pantomime of tool use. Actual tool use was examined for the same familiar tools. Forty two patients with left brain damage (LBD) and aphasia, 22 patients with right brain damage (RBD) and 22 controls were examined. Only LBD patients differed from controls on all tests. RBD patients had difficulties with the use but not with the selection of novel tools. In LBD patients there was a significant correlation between pantomime of tool use and novel tool selection but there were single cases who scored in the defective range on one of these tests and normally on the other. Analysis of LBD patients' lesions suggested that frontal lobe damage does not disturb novel tool selection. Only LBD patients who failed on pantomime of object use and on novel tool selection committed errors in actual use of familiar tools. The finding that mechanical problem solving is invariably defective in apraxic patients who commit errors with familiar tools is in good accord with clinical observations, as the gravity of their errors goes beyond what one would expect as a mere sequel
Novel Problem Solving - The NASA Solution Mechanism Guide
Keeton, Kathryn E.; Richard, Elizabeth E.; Davis, Jeffrey R.
2014-01-01
Over the past five years, the Human Health and Performance (HH&P) Directorate at the NASA Johnson Space Center (JSC) has conducted a number of pilot and ongoing projects in collaboration and open innovation. These projects involved the use of novel open innovation competitions that sought solutions from "the crowd", non-traditional problem solvers. The projects expanded to include virtual collaboration centers such as the NASA Human Health and Performance Center (NHHPC) and more recently a collaborative research project between NASA and the National Science Foundation (NSF). These novel problem-solving tools produced effective results and the HH&P wanted to capture the knowledge from these new tools, to teach the results to the directorate, and to implement new project management tools and coursework. The need to capture and teach the results of these novel problem solving tools, the HH&P decided to create a web-based tool to capture best practices and case studies, to teach novice users how to use new problem solving tools and to change project management training/. This web-based tool was developed with a small, multi-disciplinary group and named the Solution Mechanism Guide (SMG). An alpha version was developed that was tested against several sessions of user groups to get feedback on the SMG and determine a future course for development. The feedback was very positive and the HH&P decided to move to the beta-phase of development. To develop the web-based tool, the HH&P utilized the NASA Tournament Lab (NTL) to develop the software with TopCoder under an existing contract. In this way, the HH&P is using one new tool (the NTL and TopCoder) to develop the next generation tool, the SMG. The beta-phase of the SMG is planed for release in the spring of 2014 and results of the beta-phase testing will be available for the IAC meeting in September. The SMG is intended to disrupt the way problem solvers and project managers approach problem solving and to increase the
Method of mechanical quadratures for solving singular integral equations of various types
Sahakyan, A. V.; Amirjanyan, H. A.
2018-04-01
The method of mechanical quadratures is proposed as a common approach intended for solving the integral equations defined on finite intervals and containing Cauchy-type singular integrals. This method can be used to solve singular integral equations of the first and second kind, equations with generalized kernel, weakly singular equations, and integro-differential equations. The quadrature rules for several different integrals represented through the same coefficients are presented. This allows one to reduce the integral equations containing integrals of different types to a system of linear algebraic equations.
Solving the generalized Langevin equation with the algebraically correlated noise
International Nuclear Information System (INIS)
Srokowski, T.; Ploszajczak, M.
1997-01-01
The Langevin equation with the memory kernel is solved. The stochastic force possesses algebraic correlations, proportional to 1/t. The velocity autocorrelation function and related quantities characterizing transport properties are calculated at the assumption that the system is in the thermal equilibrium. Stochastic trajectories are simulated numerically, using the kangaroo process as a noise generator. Results of this simulation resemble Levy walks with divergent moments of the velocity distribution. The motion of a Brownian particle is considered both without any external potential and in the harmonic oscillator field, in particular the escape from a potential well. The results are compared with memory-free calculations for the Brownian particle. (author)
Solving Fully Fuzzy Linear System of Equations in General Form
Directory of Open Access Journals (Sweden)
A. Yousefzadeh
2012-06-01
Full Text Available In this work, we propose an approach for computing the positive solution of a fully fuzzy linear system where the coefficient matrix is a fuzzy $nimes n$ matrix. To do this, we use arithmetic operations on fuzzy numbers that introduced by Kaffman in and convert the fully fuzzy linear system into two $nimes n$ and $2nimes 2n$ crisp linear systems. If the solutions of these linear systems don't satisfy in positive fuzzy solution condition, we introduce the constrained least squares problem to obtain optimal fuzzy vector solution by applying the ranking function in given fully fuzzy linear system. Using our proposed method, the fully fuzzy linear system of equations always has a solution. Finally, we illustrate the efficiency of proposed method by solving some numerical examples.
Ekici, Didem Inel
2016-01-01
This study aimed to determine Turkish junior high-school students' perceptions of the general problem-solving process. The Turkish junior high-school students' perceptions of the general problem-solving process were examined in relation to their gender, grade level, age and their grade point with regards to the science course identified in the…
A generalized trial solution method for solving the aerosol equation
International Nuclear Information System (INIS)
Simons, S.; Simpson, D.R.
1988-01-01
It is shown how the introduction of orthogonal functions together with a time-dependent scaling factor may be used to develop a generalized trial solution method for tackling the aerosol equation. The approach is worked out in detail for the case where the initial particle size spectrum follows a γ-distribution, and it is shown to be a viable technique as long as the initial volume fraction of particulate material is not too large. The method is applied to several situations of interest, and is shown to give more accurate results (with marginally shorter computing times) than are given by the three-parameter log-normal or γ distribution trial functions. (author)
General presentation of projects mechanisms
International Nuclear Information System (INIS)
2003-01-01
This guide provides recommendations and tools to implement projects mechanisms, in the framework of the kyoto protocol. It precises the place of the projects mechanisms in the display of tools involved in the climatic change fight policies, at the national as international scale. It recalls the main characteristics and the rules of utilization and illustrates the corresponding interests. (A.L.B.)
S-equivalents lagrangians in generalized mechanics
International Nuclear Information System (INIS)
Negri, L.J.; Silva, Edna G. da.
1985-01-01
The problem of s-equivalent lagrangians is considered in the realm of generalized mechanics. Some results corresponding to the ordinary (non-generalized) mechanics are extended to the generalized case. A theorem for the reduction of the higher order lagrangian description to the usual order is found to be useful for the analysis of generalized mechanical systems and leads to a new class of equivalence between lagrangian functions. Some new perspectives are pointed out. (Author) [pt
Hidayati, H.; Ramli, R.
2018-04-01
This paper aims to provide a description of the implementation of Physic Problem Solving strategy combined with concept maps in General Physics learning at Department of Physics, Universitas Negeri Padang. Action research has been conducted in two cycles where each end of the cycle is reflected and improved for the next cycle. Implementation of Physics Problem Solving strategy combined with concept map can increase student activity in solving general physics problem with an average increase of 15% and can improve student learning outcomes from 42,7 in the cycle I become 62,7 in cycle II in general physics at the Universitas Negeri Padang. In the future, the implementation of Physic Problem Solving strategy combined with concept maps will need to be considered in Physics courses.
General principles of quantum mechanics
International Nuclear Information System (INIS)
Pauli, W.
1980-01-01
This book is a textbook for a course in quantum mechanics. Starting from the complementarity and the uncertainty principle Schroedingers equation is introduced together with the operator calculus. Then stationary states are treated as eigenvalue problems. Furthermore matrix mechanics are briefly discussed. Thereafter the theory of measurements is considered. Then as approximation methods perturbation theory and the WKB approximation are introduced. Then identical particles, spin, and the exclusion principle are discussed. There after the semiclassical theory of radiation and the relativistic one-particle problem are discussed. Finally an introduction is given into quantum electrodynamics. (HSI)
Problem-Solving Test: The Mechanism of Protein Synthesis
Szeberenyi, Jozsef
2009-01-01
Terms to be familiar with before you start to solve the test: protein synthesis, ribosomes, amino acids, peptides, peptide bond, polypeptide chain, N- and C-terminus, hemoglobin, [alpha]- and [beta]-globin chains, radioactive labeling, [[to the third power]H] and [[to the fourteenth power]C]leucine, cytosol, differential centrifugation, density…
Mataka, Lloyd M.; Cobern, William W.; Grunert, Megan L.; Mutambuki, Jacinta; Akom, George
2014-01-01
This study investigate the effectiveness of adding an "explicit general problem solving teaching strategy" (EGPS) to guided inquiry (GI) on pre-service elementary school teachers' ability to solve heat transfer problems. The pre-service elementary teachers in this study were enrolled in two sections of a chemistry course for pre-service…
A Computer Algebra Approach to Solving Chemical Equilibria in General Chemistry
Kalainoff, Melinda; Lachance, Russ; Riegner, Dawn; Biaglow, Andrew
2012-01-01
In this article, we report on a semester-long study of the incorporation into our general chemistry course, of advanced algebraic and computer algebra techniques for solving chemical equilibrium problems. The method presented here is an alternative to the commonly used concentration table method for describing chemical equilibria in general…
Directory of Open Access Journals (Sweden)
Jen-Yuan Chen
2014-01-01
Full Text Available Continuing from the works of Li et al. (2014, Li (2007, and Kincaid et al. (2000, we present more generalizations and modifications of iterative methods for solving large sparse symmetric and nonsymmetric indefinite systems of linear equations. We discuss a variety of iterative methods such as GMRES, MGMRES, MINRES, LQ-MINRES, QR MINRES, MMINRES, MGRES, and others.
Application of the Generalized Differential Quadrature Method in Solving Burgers' Equations
International Nuclear Information System (INIS)
Mokhtari, R.; Toodar, A. Samadi; Chegini, N.G.
2011-01-01
The aim of this paper is to obtain numerical solutions of the one-dimensional, two-dimensional and coupled Burgers' equations through the generalized differential quadrature method (GDQM). The polynomial-based differential quadrature (PDQ) method is employed and the obtained system of ordinary differential equations is solved via the total variation diminishing Runge-Kutta (TVD-RK) method. The numerical solutions are satisfactorily coincident with the exact solutions. The method can compete against the methods applied in the literature. (general)
The approval mechanism solves the prisoner's dilemma theoretically and experimentally
Tatsuyoshi Saijo; Yoshitaka Okano; Takafumi Yamakawa
2015-01-01
Consider a situation where players in a prisoner's dilemma game can approve or reject the other's choice such as cooperation or defection. If both players approve the other's choice, the outcome is the one they chose, whereas if either one rejects the other's choice, the outcome is the one when both defect, which we name the approval mechanism herein (this is inspired by the Cold War doctrine of mutually assured destruction). Experimentally, we find that the cooperation rate with the approval...
Shen, Peiping; Zhang, Tongli; Wang, Chunfeng
2017-01-01
This article presents a new approximation algorithm for globally solving a class of generalized fractional programming problems (P) whose objective functions are defined as an appropriate composition of ratios of affine functions. To solve this problem, the algorithm solves an equivalent optimization problem (Q) via an exploration of a suitably defined nonuniform grid. The main work of the algorithm involves checking the feasibility of linear programs associated with the interesting grid points. It is proved that the proposed algorithm is a fully polynomial time approximation scheme as the ratio terms are fixed in the objective function to problem (P), based on the computational complexity result. In contrast to existing results in literature, the algorithm does not require the assumptions on quasi-concavity or low-rank of the objective function to problem (P). Numerical results are given to illustrate the feasibility and effectiveness of the proposed algorithm.
Generalized mechanics as a representation of the ordinary mechanics
International Nuclear Information System (INIS)
Knapecz, G.
1974-01-01
It is shown that the generalized mechanics of one masspoint may be interpreted as a special representation of the ordinary mechanics of a system of masspoints. The hormorphism of both representations is shown in the case of two masspoints coupled by a harmonic force. The new representation is applied in the special relativic meachanics of mass-points. (author)
Quantum mechanics as a natural generalization of classical statistical mechanics
International Nuclear Information System (INIS)
Xu Laizi; Qian Shangwu
1994-01-01
By comparison between equations of motion of geometrical optics (GO) and that of classical statistical mechanics (CSM), it is found that there should be an analogy between GO and CSM instead of GO and classical mechanics (CM). Furthermore, by comparison between the classical limit (CL) of quantum mechanics (QM) and CSM, the authors find that CL of QM is CSM not CM, hence they demonstrated that QM is a natural generalization of CSM instead of CM
A Generalized FDM for solving the Poisson's Equation on 3D Irregular Domains
Directory of Open Access Journals (Sweden)
J. Izadian
2014-01-01
Full Text Available In this paper a new method for solving the Poisson's equation with Dirichlet conditions on irregular domains is presented. For this purpose a generalized finite differences method is applied for numerical differentiation on irregular meshes. Three examples on cylindrical and spherical domains are considered. The numerical results are compared with analytical solution. These results show the performance and efficiency of the proposed method.
Advanced mechanics and general relativity an introduction to general relativity
Franklin, Joel
2010-01-01
Aimed at advanced undergraduates with background knowledge of classical mechanics and electricity and magnetism, this textbook presents both the particle dynamics relevant to general relativity, and the field dynamics necessary to understand the theory. Focusing on action extremization, the book develops the structure and predictions of general relativity by analogy with familiar physical systems. Topics ranging from classical field theory to minimal surfaces and relativistic strings are covered in a homogeneous manner. Nearly 150 exercises and numerous examples throughout the textbook enable students to test their understanding of the material covered.
Mechanical problem-solving strategies in Alzheimer's disease and semantic dementia.
Lesourd, Mathieu; Baumard, Josselin; Jarry, Christophe; Etcharry-Bouyx, Frédérique; Belliard, Serge; Moreaud, Olivier; Croisile, Bernard; Chauviré, Valérie; Granjon, Marine; Le Gall, Didier; Osiurak, François
2016-07-01
The goal of this study was to explore whether the tool-use disorders observed in Alzheimer's disease (AD) and semantic dementia (SD) are of the same nature as those observed in left brain-damaged (LBD) patients. Recent evidence indicates that LBD patients with apraxia of tool use encounter difficulties in solving mechanical problems, characterized by the absence of specific strategies. This pattern may show the presence of impaired mechanical knowledge, critical for both familiar and novel tool use. So, we explored the strategies followed by AD and SD patients in mechanical problem-solving tasks in order to determine whether mechanical knowledge is also impaired in these patients. We used a mechanical problem-solving task in both choice (i.e., several tools were proposed) and no-choice (i.e., only 1 tool was proposed) conditions. We analyzed quantitative data and strategy profiles. AD patients but not SD patients met difficulties in solving mechanical problem-solving tasks. However, the key finding is that AD patients, despite their difficulties, showed strategy profiles that are similar to that of SD patients or controls. Moreover, AD patients exhibited a strategy profile distinct from the one previously observed in LBD patients. Those observations lead us to consider that difficulties met by AD patients to solve mechanical problems or even to use familiar tools may not be caused by mechanical knowledge impairment per se. In broad terms, what we call apraxia of tool use in AD is certainly not the same as apraxia of tool use observed in LBD patients. (PsycINFO Database Record (c) 2016 APA, all rights reserved).
A theory of solving TAP equations for Ising models with general invariant random matrices
DEFF Research Database (Denmark)
Opper, Manfred; Çakmak, Burak; Winther, Ole
2016-01-01
We consider the problem of solving TAP mean field equations by iteration for Ising models with coupling matrices that are drawn at random from general invariant ensembles. We develop an analysis of iterative algorithms using a dynamical functional approach that in the thermodynamic limit yields...... the iteration dependent on a Gaussian distributed field only. The TAP magnetizations are stable fixed points if a de Almeida–Thouless stability criterion is fulfilled. We illustrate our method explicitly for coupling matrices drawn from the random orthogonal ensemble....
Balasubrahmanya Hegde; B. N. Meera
2012-01-01
A perceived difficulty is associated with physics problem solving from a learner’s viewpoint, arising out of a multitude of reasons. In this paper, we have examined the microstructure of students’ thought processes during physics problem solving by combining the analysis of responses to multiple-choice questions and semistructured student interviews. Design of appropriate scaffoldings serves as pointers to the identification of student problem solving difficulties. An analysis of the results ...
Directory of Open Access Journals (Sweden)
Balasubrahmanya Hegde
2012-03-01
Full Text Available A perceived difficulty is associated with physics problem solving from a learner’s viewpoint, arising out of a multitude of reasons. In this paper, we have examined the microstructure of students’ thought processes during physics problem solving by combining the analysis of responses to multiple-choice questions and semistructured student interviews. Design of appropriate scaffoldings serves as pointers to the identification of student problem solving difficulties. An analysis of the results suggests the necessity of identification of the skill sets required for developing better problem solving abilities.
Hegde, Balasubrahmanya; Meera, B. N.
2012-01-01
A perceived difficulty is associated with physics problem solving from a learner's viewpoint, arising out of a multitude of reasons. In this paper, we have examined the microstructure of students' thought processes during physics problem solving by combining the analysis of responses to multiple-choice questions and semistructured student…
Capturing Students' Abstraction While Solving Organic Reaction Mechanism Problems across a Semester
Weinrich, M. L.; Sevian, H.
2017-01-01
Students often struggle with solving mechanism problems in organic chemistry courses. They frequently focus on surface features, have difficulty attributing meaning to symbols, and do not recognize tasks that are different from the exact tasks practiced. To be more successful, students need to be able to extract salient features, map similarities…
Frequent attenders in general practice: problem solving treatment provided by nurses [ISRCTN51021015
Directory of Open Access Journals (Sweden)
van Oppen P
2005-10-01
Full Text Available Abstract Background There is a need for assistance from primary care mental health workers in general practice in the Netherlands. General practitioners (GPs experience an overload of frequent attenders suffering from psychological problems. Problem Solving Treatment (PST is a brief psychological treatment tailored for use in a primary care setting. PST is provided by nurses, and earlier research has shown that it is a treatment at least as effective as usual care. However, research outcomes are not totally satisfying. This protocol describes a randomized clinical trial on the effectiveness of PST provided by nurses for patients in general practice. The results of this study, which currently being carried out, will be presented as soon as they are available. Methods/design This study protocol describes the design of a randomized controlled trial to investigate the effectiveness and cost-effectiveness of PST and usual care compared to usual care only. Patients, 18 years and older, who present psychological problems and are frequent attenders in general practice are recruited by the research assistant. The participants receive questionnaires at baseline, after the intervention, and again after 3 months and 9 months. Primary outcome is the reduction of symptoms, and other outcomes measured are improvement in problem solving skills, psychological and physical well being, daily functioning, social support, coping styles, problem evaluation and health care utilization. Discussion Our results may either confirm that PST in primary care is an effective way of dealing with emotional disorders and a promising addition to the primary care in the UK and USA, or may question this assumption. This trial will allow an evaluation of the effects of PST in practical circumstances and in a rather heterogeneous group of primary care patients. This study delivers scientific support for this use and therefore indications for optimal treatment and referral.
Generalized bond percolation and statistical mechanics
International Nuclear Information System (INIS)
Tsallis, C.
1978-05-01
A generalization of traditional bond percolation is performed, in the sens that bonds have now the possibility of partially transmitting the information (a fact which leads to the concept of 'fidelity' of the bond), and also in the sens that, besides the normal tendency to equiprobability, the bonds are allowed to substantially change the information. Furthermore the fidelity is allowed, to become an aleatory variable, and the operational rules concerning the associated distribution laws are determined. Thermally quenched random bonds and the whole body of Statistical Mechanics become particular cases of this formalism, which is in general adapted to the treatment of all problems whose main characteristic is to preserve a part of the information through a long path or array (critical phenomena, regime changements, thermal random models, etc). Operationally it provides a quick method for the calculation of the equivalent probability of complex clusters within the traditional bond percolation problem [pt
General mechanism for the 1 /f noise
Yadav, Avinash Chand; Ramaswamy, Ramakrishna; Dhar, Deepak
2017-08-01
We consider the response of a memoryless nonlinear device that acts instantaneously, converting an input signal ξ (t ) into an output η (t ) at the same time t . For input Gaussian noise with power-spectrum 1 /fα , the nonlinearity can modify the spectral index of the output to give a spectrum that varies as 1 /fα ' with α'≠α . We show that the value of α' depends on the nonlinear transformation and can be tuned continuously. This provides a general mechanism for the ubiquitous 1 /f noise found in nature.
The effect of a preceding cue on the conflict solving mechanism.
Goldfarb, Liat; Henik, Avishai
2013-01-01
In everyday life cues and signs are used in order to improve our performance and to modify and control our behavior. This study examines whether cues can improve the performance of the mental mechanism in charge of solving conflicts when the nature of the irrelevant task remains constant. In two experiments participants performed the Stroop task in which they were asked to name the color of a stimulus while ignoring its meaning. Half the trials were preceded by a conflict-cue containing information about an upcoming conflict. In addition, conflict trial proportions were manipulated. We found that only when the probability of conflict is low can cues alter the conflict solving mechanism. These findings are discussed in the context of the nature of the control mechanism and its tendency to minimize the cost of mental resources.
Sweller, John; Clark, Richard; Kirschner, Paul A.
2010-01-01
Sweller, J., Clark, R., & Kirschner, P. A. (2010). Teaching general problem-solving skills is not a substitute for, or a viable addition to, teaching mathematics. Notices of the American Mathematical Society, 57, 1303-1304.
Identification of general linear mechanical systems
Sirlin, S. W.; Longman, R. W.; Juang, J. N.
1983-01-01
Previous work in identification theory has been concerned with the general first order time derivative form. Linear mechanical systems, a large and important class, naturally have a second order form. This paper utilizes this additional structural information for the purpose of identification. A realization is obtained from input-output data, and then knowledge of the system input, output, and inertia matrices is used to determine a set of linear equations whereby we identify the remaining unknown system matrices. Necessary and sufficient conditions on the number, type and placement of sensors and actuators are given which guarantee identificability, and less stringent conditions are given which guarantee generic identifiability. Both a priori identifiability and a posteriori identifiability are considered, i.e., identifiability being insured prior to obtaining data, and identifiability being assured with a given data set.
Solving the patient zero inverse problem by using generalized simulated annealing
Menin, Olavo H.; Bauch, Chris T.
2018-01-01
Identifying patient zero - the initially infected source of a given outbreak - is an important step in epidemiological investigations of both existing and emerging infectious diseases. Here, the use of the Generalized Simulated Annealing algorithm (GSA) to solve the inverse problem of finding the source of an outbreak is studied. The classical disease natural histories susceptible-infected (SI), susceptible-infected-susceptible (SIS), susceptible-infected-recovered (SIR) and susceptible-infected-recovered-susceptible (SIRS) in a regular lattice are addressed. Both the position of patient zero and its time of infection are considered unknown. The algorithm performance with respect to the generalization parameter q˜v and the fraction ρ of infected nodes for whom infection was ascertained is assessed. Numerical experiments show the algorithm is able to retrieve the epidemic source with good accuracy, even when ρ is small, but present no evidence to support that GSA performs better than its classical version. Our results suggest that simulated annealing could be a helpful tool for identifying patient zero in an outbreak where not all cases can be ascertained.
Mechanical problem-solving strategies in left-brain damaged patients and apraxia of tool use.
Osiurak, François; Jarry, Christophe; Lesourd, Mathieu; Baumard, Josselin; Le Gall, Didier
2013-08-01
Left brain damage (LBD) can impair the ability to use familiar tools (apraxia of tool use) as well as novel tools to solve mechanical problems. Thus far, the emphasis has been placed on quantitative analyses of patients' performance. Nevertheless, the question still to be answered is, what are the strategies employed by those patients when confronted with tool use situations? To answer it, we asked 16 LBD patients and 43 healthy controls to solve mechanical problems by means of several potential tools. To specify the strategies, we recorded the time spent in performing four kinds of action (no manipulation, tool manipulation, box manipulation, and tool-box manipulation) as well as the number of relevant and irrelevant tools grasped. We compared LBD patients' performance with that of controls who encountered difficulties with the task (controls-) or not (controls+). Our results indicated that LBD patients grasped a higher number of irrelevant tools than controls+ and controls-. Concerning time allocation, controls+ and controls- spent significantly more time in performing tool-box manipulation than LBD patients. These results are inconsistent with the possibility that LBD patients could engage in trial-and-error strategies and, rather, suggest that they tend to be perplexed. These findings seem to indicate that the inability to reason about the objects' physical properties might prevent LBD patients from following any problem-solving strategy. Copyright © 2013 Elsevier Ltd. All rights reserved.
An extended step characteristic method for solving the transport equation in general geometries
International Nuclear Information System (INIS)
DeHart, M.D.; Pevey, R.E.; Parish, T.A.
1994-01-01
A method for applying the discrete ordinates method to solve the Boltzmann transport equation on arbitrary two-dimensional meshes has been developed. The finite difference approach normally used to approximate spatial derivatives in extrapolating angular fluxes across a cell is replaced by direct solution of the characteristic form of the transport equation for each discrete direction. Thus, computational cells are not restricted to the geometrical shape of a mesh element characteristic of a given coordinate system. However, in terms of the treatment of energy and angular dependencies, this method resembles traditional discrete ordinates techniques. By using the method developed here, a general two-dimensional space can be approximated by an irregular mesh comprised of arbitrary polygons. Results for a number of test problems have been compared with solutions obtained from traditional methods, with good agreement. Comparisons include benchmarks against analytical results for problems with simple geometry, as well as numerical results obtained from traditional discrete ordinates methods by applying the ANISN and TWOTRAN-II computer programs
DEFF Research Database (Denmark)
Helsgaun, Keld
2015-01-01
instances in a well-known library of benchmark instances, GTSPLIB, could be solved to optimality in a reasonable time. In addition, it was possible to solve a series of new very-large-scale instances with up to 17,180 clusters and 85,900 vertices. Optima for these instances are not known...... be downloaded in source code....
Higher-derivative generalization of conformal mechanics
Baranovsky, Oleg
2017-08-01
Higher-derivative analogs of multidimensional conformal particle and many-body conformal mechanics are constructed. Their Newton-Hooke counterparts are derived by applying appropriate coordinate transformations.
General approach for solving the density gradient theory in the interfacial tension calculations
DEFF Research Database (Denmark)
Liang, Xiaodong; Michelsen, Michael Locht
2017-01-01
Within the framework of the density gradient theory, the interfacial tension can be calculated by finding the density profiles that minimize an integral of two terms over the system of infinite width. It is found that the two integrands exhibit a constant difference along the interface for a finite...... property evaluations compared to other methods. The performance of the algorithm with recommended parameters is analyzed for various systems, and the efficiency is further compared with the geometric-mean density gradient theory, which only needs to solve nonlinear algebraic equations. The results show...... that the algorithm is only 5-10 times less efficient than solving the geometric-mean density gradient theory....
Solving Nonlinear Fractional Differential Equation by Generalized Mittag-Leffler Function Method
Arafa, A. A. M.; Rida, S. Z.; Mohammadein, A. A.; Ali, H. M.
2013-06-01
In this paper, we use Mittag—Leffler function method for solving some nonlinear fractional differential equations. A new solution is constructed in power series. The fractional derivatives are described by Caputo's sense. To illustrate the reliability of the method, some examples are provided.
46 CFR 154.1200 - Mechanical ventilation system: General.
2010-10-01
... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: General. 154.1200 Section... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a...
Baumann, Gerd
2005-01-01
Mathematica for Theoretical Physics: Electrodynamics, Quantum Mechanics, General Relativity, and Fractals This second edition of Baumann's Mathematica® in Theoretical Physics shows readers how to solve physical problems and deal with their underlying theoretical concepts while using Mathematica® to derive numeric and symbolic solutions. Each example and calculation can be evaluated by the reader, and the reader can change the example calculations and adopt the given code to related or similar problems. The second edition has been completely revised and expanded into two volumes: The first volume covers classical mechanics and nonlinear dynamics. Both topics are the basis of a regular mechanics course. The second volume covers electrodynamics, quantum mechanics, relativity, and fractals and fractional calculus. New examples have been added and the representation has been reworked to provide a more interactive problem-solving presentation. This book can be used as a textbook or as a reference work, by student...
Mechanics of extended masses in general relativity
International Nuclear Information System (INIS)
Harte, Abraham I
2012-01-01
The 'external' or 'Right' motion of extended bodies is studied in general relativity. Compact material objects of essentially arbitrary shape, spin, internal composition and velocity are allowed as long as there is no direct (non-gravitational) contact with other sources of stress-energy. Physically reasonable linear and angular momenta are proposed for such bodies and exact equations describing their evolution are derived. Changes in the momenta depend on a certain 'effective metric' that is closely related to a non-perturbative generalization of the Detweiler-Whiting R-field originally introduced in the self-force literature. If the effective metric inside a self-gravitating body can be adequately approximated by an appropriate power series, the instantaneous gravitational force and torque exerted on it is shown to be identical to the force and torque exerted on an appropriate test body moving in the effective metric. This result holds to all multipole orders. The only instantaneous effect of a body's self-field is to finitely renormalize the 'bare' multipole moments of its stress-energy tensor. The MiSaTaQuWa expression for the gravitational self-force is recovered as a simple application. A gravitational self-torque is obtained as well. Lastly, it is shown that the effective metric in which objects appear to move is approximately a solution to the vacuum Einstein equation if the physical metric is an approximate solution to Einstein's equation linearized about a vacuum background. (paper)
International Nuclear Information System (INIS)
Kumar, V.; Sahni, D.C.
1983-01-01
In this paper, the authors present the mathematical techniques that were developed for solving the integral transport equation for the criticality of a homogeneous cylinder of finite height with general anisotropic scattering. They present the integral transport equations for the Fourier transformed spherical harmonic moments of the angular flux. These moments are also represented by a series of products of spherical Bessel functions. The criticality problem is, then, posed by the matrix eigenvalue problem whose eigenvector is composed of the expansion coefficients mentioned above. An methodology of calculating the general matrix element is discussed by using the recursion relations derived in this paper. Finally, for the one-group criticality of finite cylinders, the benchmark results are generated when scattering is linearly anisotropic. Also, these benchmarks are solved and compared with the S/sub N/ method of TWOTRAN
Hook, Richard J.
1993-01-01
A self-administered problem-solving skill training video for nonclinical families with teens is evaluated. The study focuses on the generalization of skills to naturalistic family conversations and the program's social validity: potential iatrogenic aggravation of family problems, perceived effectiveness, and program enjoyment. Seventy families with young teens were randomly assigned to two treatment groups. One group (skill) viewed a skill training program that included information about ...
Application of symbolic and algebraic manipulation software in solving applied mechanics problems
Tsai, Wen-Lang; Kikuchi, Noboru
1993-01-01
As its name implies, symbolic and algebraic manipulation is an operational tool which not only can retain symbols throughout computations but also can express results in terms of symbols. This report starts with a history of symbolic and algebraic manipulators and a review of the literatures. With the help of selected examples, the capabilities of symbolic and algebraic manipulators are demonstrated. These applications to problems of applied mechanics are then presented. They are the application of automatic formulation to applied mechanics problems, application to a materially nonlinear problem (rigid-plastic ring compression) by finite element method (FEM) and application to plate problems by FEM. The advantages and difficulties, contributions, education, and perspectives of symbolic and algebraic manipulation are discussed. It is well known that there exist some fundamental difficulties in symbolic and algebraic manipulation, such as internal swelling and mathematical limitation. A remedy for these difficulties is proposed, and the three applications mentioned are solved successfully. For example, the closed from solution of stiffness matrix of four-node isoparametrical quadrilateral element for 2-D elasticity problem was not available before. Due to the work presented, the automatic construction of it becomes feasible. In addition, a new advantage of the application of symbolic and algebraic manipulation found is believed to be crucial in improving the efficiency of program execution in the future. This will substantially shorten the response time of a system. It is very significant for certain systems, such as missile and high speed aircraft systems, in which time plays an important role.
Directory of Open Access Journals (Sweden)
Олена Валентинівна Лупаренко
2015-03-01
Full Text Available When the wave processes in bounded elastic bodies are examined, we are faced with a significant complication of the structure of the wave field compared to the case of infinite bodies. This is due to the complex nature of the reflection of elastic waves from the boundaries of the body because the direction of the general flow of energy is changed. Even more complicated the structure of the wave field is, if there are inner boundaries between fields with different elastic properties. This entails the emergence of new wave effects associated with the dynamic stress concentration in the vicinity of the internal and external boundaries of the field. The nature of edge effects is changed too. They will depend not only from the size of the field but also from the geometric and elastic parameters defining the nature of heterogeneity. At the forefront are the questions of systematization of the results for the purpose of extradition of practical recommendations for optimal design of heterogeneous section details in particular conditions of its operation. Urgent enough is the question of the possibility of neglecting of structural heterogeneity and anisotropy of the section of the body in strengthening calculations and evaluation of possible errors. The mathematical basis for the study will be the expressions for particular solutions of equations of motion, constructed for infinite layers, which are sets of plane standing waves. When choosing the form of partial solutions, we must take into account not only the opportunity to satisfy the boundary conditions at the exterior boundary of the field, but also the mechanical properties at the interface of the sphere. This entails the complication of numerical-analytical algorithm of solving the problem
Khader, M M
2013-10-01
In this paper, an efficient numerical method for solving the fractional delay differential equations (FDDEs) is considered. The fractional derivative is described in the Caputo sense. The proposed method is based on the derived approximate formula of the Laguerre polynomials. The properties of Laguerre polynomials are utilized to reduce FDDEs to a linear or nonlinear system of algebraic equations. Special attention is given to study the error and the convergence analysis of the proposed method. Several numerical examples are provided to confirm that the proposed method is in excellent agreement with the exact solution.
A new approach for solving the three-dimensional steady Euler equations. I - General theory
Chang, S.-C.; Adamczyk, J. J.
1986-01-01
The present iterative procedure combines the Clebsch potentials and the Munk-Prim (1947) substitution principle with an extension of a semidirect Cauchy-Riemann solver to three dimensions, in order to solve steady, inviscid three-dimensional rotational flow problems in either subsonic or incompressible flow regimes. This solution procedure can be used, upon discretization, to obtain inviscid subsonic flow solutions in a 180-deg turning channel. In addition to accurately predicting the behavior of weak secondary flows, the algorithm can generate solutions for strong secondary flows and will yield acceptable flow solutions after only 10-20 outer loop iterations.
some generalized two-step block hybrid numerov method for solving ...
African Journals Online (AJOL)
Nwokem et al.
ABSTRACT. This paper proposes a class of generalized two-step Numerov methods, a block hybrid type for the direct solution of general second order ordinary differential equations. Both the main method and additional methods were derived via interpolation and collocation procedures. The basic properties of zero ...
A Simulated Annealing method to solve a generalized maximal covering location problem
Directory of Open Access Journals (Sweden)
M. Saeed Jabalameli
2011-04-01
Full Text Available The maximal covering location problem (MCLP seeks to locate a predefined number of facilities in order to maximize the number of covered demand points. In a classical sense, MCLP has three main implicit assumptions: all or nothing coverage, individual coverage, and fixed coverage radius. By relaxing these assumptions, three classes of modelling formulations are extended: the gradual cover models, the cooperative cover models, and the variable radius models. In this paper, we develop a special form of MCLP which combines the characteristics of gradual cover models, cooperative cover models, and variable radius models. The proposed problem has many applications such as locating cell phone towers. The model is formulated as a mixed integer non-linear programming (MINLP. In addition, a simulated annealing algorithm is used to solve the resulted problem and the performance of the proposed method is evaluated with a set of randomly generated problems.
Engineering a General Education Program: Designing Mechanical Engineering General Education Courses
Fagette, Paul; Chen, Shih-Jiun; Baran, George R.; Samuel, Solomon P.; Kiani, Mohammad F.
2013-01-01
The Department of Mechanical Engineering at our institution created two engineering courses for the General Education Program that count towards second level general science credit (traditional science courses are first level). The courses were designed for the general student population based upon the requirements of our General Education Program…
A Hybrid Dynamic Programming for Solving Fixed Cost Transportation with Discounted Mechanism
Directory of Open Access Journals (Sweden)
Farhad Ghassemi Tari
2016-01-01
Full Text Available The problem of allocating different types of vehicles for transporting a set of products from a manufacturer to its depots/cross docks, in an existing transportation network, to minimize the total transportation costs, is considered. The distribution network involves a heterogeneous fleet of vehicles, with a variable transportation cost and a fixed cost in which a discount mechanism is applied on the fixed part of the transportation costs. It is assumed that the number of available vehicles is limited for some types. A mathematical programming model in the form of the discrete nonlinear optimization model is proposed. A hybrid dynamic programming algorithm is developed for finding the optimal solution. To increase the computational efficiency of the solution algorithm, several concepts and routines, such as the imbedded state routine, surrogate constraint concept, and bounding schemes, are incorporated in the dynamic programming algorithm. A real world case problem is selected and solved by the proposed solution algorithm, and the optimal solution is obtained.
Parand, Kourosh; Latifi, Sobhan; Delkhosh, Mehdi; Moayeri, Mohammad M.
2018-01-01
In the present paper, a new method based on the Generalized Lagrangian Jacobi Gauss (GLJG) collocation method is proposed. The nonlinear Kidder equation, which explains unsteady isothermal gas through a micro-nano porous medium, is a second-order two-point boundary value ordinary differential equation on the unbounded interval [0, ∞). Firstly, using the quasilinearization method, the equation is converted to a sequence of linear ordinary differential equations. Then, by using the GLJG collocation method, the problem is reduced to solving a system of algebraic equations. It must be mentioned that this equation is solved without domain truncation and variable changing. A comparison with some numerical solutions made and the obtained results indicate that the presented solution is highly accurate. The important value of the initial slope, y'(0), is obtained as -1.191790649719421734122828603800159364 for η = 0.5. Comparing to the best result obtained so far, it is accurate up to 36 decimal places.
Ltaief, Hatem; Luszczek, Piotr R.; Haidar, Azzam; Dongarra, Jack
2012-01-01
This paper proposes an efficient implementation of the generalized symmetric eigenvalue problem on multicore architecture. Based on a four-stage approach and tile algorithms, the original problem is first transformed into a standard symmetric
BOOK REVIEW: Advanced Mechanics and General Relativity Advanced Mechanics and General Relativity
Louko, Jorma
2011-04-01
Joel Franklin's textbook `Advanced Mechanics and General Relativity' comprises two partially overlapping, partially complementary introductory paths into general relativity at advanced undergraduate level. Path I starts with the Lagrangian and Hamiltonian formulations of Newtonian point particle motion, emphasising the action principle and the connection between symmetries and conservation laws. The concepts are then adapted to point particle motion in Minkowski space, introducing Lorentz transformations as symmetries of the action. There follows a focused development of tensor calculus, parallel transport and curvature, using examples from Newtonian mechanics and special relativity, culminating in the field equations of general relativity. The Schwarzschild solution is analysed, including a detailed discussion of the tidal forces on a radially infalling observer. Basics of gravitational radiation are examined, highlighting the similarities to and differences from electromagnetic radiation. The final topics in Path I are equatorial geodesics in Kerr and the motion of a relativistic string in Minkowski space. Path II starts by introducing scalar field theory on Minkowski space as a limit of point masses connected by springs, emphasising the action principle, conservation laws and the energy-momentum tensor. The action principle for electromagnetism is introduced, and the coupling of electromagnetism to a complex scalar field is developed in a detailed and pedagogical fashion. A free symmetric second-rank tensor field on Minkowski space is introduced, and the action principle of general relativity is recovered from coupling the second-rank tensor to its own energy-momentum tensor. Path II then merges with Path I and, supplanted with judicious early selections from Path I, can proceed to the Schwarzschild solution. The choice of material in each path is logical and focused. A notable example in Path I is that Lorentz transformations in Minkowki space are introduced
Directory of Open Access Journals (Sweden)
V. M. Magilevets
2009-01-01
Full Text Available The computerized system to control depth of anesthesia during surgical operation was developed in our research center. The depth of anesthesia is regulated by controlled intravenous infusion of propofol. The varied propofol rate is controlled by the closed-loop propofol system (CLPS with mean arterial pressure (MAP controller. MAP is used in the CLPS as input parameter and indicator of anesthesia depth. CLPS consists PC, invasive blood pressure (BP sensor and Graseby 3400 infusion pump. The C language computer program sets the propofol infusion rate based on empirical algorithm including proportional component to maintain the measured MAP more closely to the target MAP (85% of patient standard MAP. The propofol concentrations are calculated by Runge–Kutta’s method PK/PD model differential equations solving with Marsh’s microconstants and Kazama’s BIS effect site microconstant and age depended BP effect site microconstants every 30 s. The designed CLPS was effective and useful for anesthesia maintenance during open-heart surgery, especially for early extubation.
Directory of Open Access Journals (Sweden)
P. G. Klyucharev
2017-01-01
Full Text Available A number of previous author’s papers proposed methods for constructing various cryptographic algorithms, including block ciphers and cryptographic hash functions, based on generalized cellular automata. This one is aimed at studying a possibility to use the algebraic cryptanalysis methods related to the construction of Gröbner bases for the generalized cellular automata to be applied in cryptography, i.e. this paper studies the possibility for using algebraic cryptanalysis methods to solve the problems of inversion of a generalized cellular automaton and recovering the key of such an automaton.If the cryptographic algorithm is represented as a system of polynomial equations over a certain finite field, then its breach is reduced to solving this system with respect to the key. Although the problem of solving a system of polynomial equations in a finite field is NP-difficult in the general case, the solution of a particular system can have low computational cost.Cryptanalysis based on the construction of a system of polynomial equations that links plain text, cipher-text and key, and its solution by algebraic methods, is usually called algebraic cryptanalysis. Among the main methods to solve systems of polynomial equations are those to construct Gröbner bases.Cryptanalysis of ciphers and hash functions based on generalized cellular automata can be reduced to various problems. We will consider two such problems: the problem of inversion of a generalized cellular automaton, which, in case we know the values of the cells after k iterations, enables us to find the initial values. And the task of recovering the key, which is to find the initial values of the remaining cells, using the cell values after k steps and the initial values of a part of the cells.A computational experiment was carried out to solve the two problems above stated in order to determine the maximum size of a generalized cellular automaton for which the solution of these
Solving the AKNS Hierarchy by Its Bilinear Form: Generalized Double Wronskian Solutions
International Nuclear Information System (INIS)
Yin Fumei; Sun Yepeng; Cai Fuqing; Chen Dengyuan
2008-01-01
Through the Wronskian technique, a simple and direct proof is presented that the AKNS hierarchy in the bilinear form has generalized double Wronskian solutions. Moreover, by using a unified way, soliton solutions, rational solutions, Matveev solutions and complexitons in double Wronskian form for it are constructed.
DEFF Research Database (Denmark)
Bendtsen, Claus; Nielsen, Ole Holm; Hansen, Lars Bruno
2001-01-01
The quantum mechanical ground state of electrons is described by Density Functional Theory, which leads to large minimization problems. An efficient minimization method uses a self-consistent field (SCF) solution of large eigenvalue problems. The iterative Davidson algorithm is often used, and we...
Directory of Open Access Journals (Sweden)
Ning Li
2013-01-01
Full Text Available The matrix equation ∑l=1uAlXBl+∑s=1vCsXTDs=F, which includes some frequently investigated matrix equations as its special cases, plays important roles in the system theory. In this paper, we propose an iterative algorithm for solving the quaternion matrix equation ∑l=1uAlXBl+∑s=1vCsXTDs=F over generalized (P,Q-reflexive matrices. The proposed iterative algorithm automatically determines the solvability of the quaternion matrix equation over generalized (P,Q-reflexive matrices. When the matrix equation is consistent over generalized (P,Q-reflexive matrices, the sequence {X(k} generated by the introduced algorithm converges to a generalized (P,Q-reflexive solution of the quaternion matrix equation. And the sequence {X(k} converges to the least Frobenius norm generalized (P,Q-reflexive solution of the quaternion matrix equation when an appropriate initial iterative matrix is chosen. Furthermore, the optimal approximate generalized (P,Q-reflexive solution for a given generalized (P,Q-reflexive matrix X0 can be derived. The numerical results indicate that the iterative algorithm is quite efficient.
Research Projects in Physics: A Mechanism for Teaching Ill-Structured Problem Solving
Milbourne, Jeff; Bennett, Jonathan
2017-10-01
Physics education research has a tradition of studying problem solving, exploring themes such as physical intuition and differences between expert and novice problem solvers. However, most of this work has focused on traditional, or well-structured, problems, similar to what might appear in a textbook. Less work has been done with open-ended, or ill-structured, problems, similar to the types of problems students might face in their professional lives. Given the national discourse on educational system reform aligned with 21st century skills, including problem solving, it is critical to provide educational experiences that help students learn to solve all types of problems, including ill-structured problems.
Directory of Open Access Journals (Sweden)
Imtiaz Wasim
2018-01-01
Full Text Available In this study, we introduce a new numerical technique for solving nonlinear generalized Burgers-Fisher and Burgers-Huxley equations using hybrid B-spline collocation method. This technique is based on usual finite difference scheme and Crank-Nicolson method which are used to discretize the time derivative and spatial derivatives, respectively. Furthermore, hybrid B-spline function is utilized as interpolating functions in spatial dimension. The scheme is verified unconditionally stable using the Von Neumann (Fourier method. Several test problems are considered to check the accuracy of the proposed scheme. The numerical results are in good agreement with known exact solutions and the existing schemes in literature.
Tschentscher, Nadja; Hauk, Olaf
2014-05-15
A number of previous studies have interpreted differences in brain activation between arithmetic operation types (e.g. addition and multiplication) as evidence in favor of distinct cortical representations, processes or neural systems. It is still not clear how differences in general task complexity contribute to these neural differences. Here, we used a mental arithmetic paradigm to disentangle brain areas related to general problem solving from those involved in operation type specific processes (addition versus multiplication). We orthogonally varied operation type and complexity. Importantly, complexity was defined not only based on surface criteria (for example number size), but also on the basis of individual participants' strategy ratings, which were validated in a detailed behavioral analysis. We replicated previously reported operation type effects in our analyses based on surface criteria. However, these effects vanished when controlling for individual strategies. Instead, procedural strategies contrasted with memory retrieval reliably activated fronto-parietal and motor regions, while retrieval strategies activated parietal cortices. This challenges views that operation types rely on partially different neural systems, and suggests that previously reported differences between operation types may have emerged due to invalid measures of complexity. We conclude that mental arithmetic is a powerful paradigm to study brain networks of abstract problem solving, as long as individual participants' strategies are taken into account. Copyright © 2014 Elsevier Inc. All rights reserved.
Ltaief, Hatem
2012-01-01
This paper proposes an efficient implementation of the generalized symmetric eigenvalue problem on multicore architecture. Based on a four-stage approach and tile algorithms, the original problem is first transformed into a standard symmetric eigenvalue problem by computing the Cholesky factorization of the right hand side symmetric definite positive matrix (first stage), and applying the inverse of the freshly computed triangular Cholesky factors to the original dense symmetric matrix of the problem (second stage). Calculating the eigenpairs of the resulting problem is then equivalent to the eigenpairs of the original problem. The computation proceeds by reducing the updated dense symmetric matrix to symmetric band form (third stage). The band structure is further reduced by applying a bulge chasing procedure, which annihilates the extra off-diagonal entries using orthogonal transformations (fourth stage). More details on the third and fourth stage can be found in Haidar et al. [Accepted at SC\\'11, November 2011]. The eigenvalues are then calculated from the tridiagonal form using the standard LAPACK QR algorithm (i.e., DTSEQR routine), while the complex and challenging eigenvector computations will be addressed in a companion paper. The tasks from the various stages can concurrently run in an out-of-order fashion. The data dependencies are cautiously tracked by the dynamic runtime system environment QUARK, which ensures the dependencies are not violated for numerical correctness purposes. The obtained tile four-stage generalized symmetric eigenvalue solver significantly outperforms the state-of-the-art numerical libraries (up to 21-fold speed up against multithreaded LAPACK with optimized multithreaded MKL BLAS and up to 4-fold speed up against the corresponding routine from the commercial numerical software Intel MKL) on four sockets twelve cores AMD system with a 24000×24000 matrix size. © 2012 The authors and IOS Press. All rights reserved.
Comments on microscopic mechanics, generalizations of classical mechanics and Planck's oscillators
International Nuclear Information System (INIS)
Yussouff, M.
1983-05-01
The new microscopic mechanics removes the dichotomy of physics into classical and quantum phenomena. Its physical picture and connections with generalizations of classical mechanics are discussed. It gives a new meaning to Bohr's frequency relation and Planck's oscillators. (author)
Mechanical similarity as a generalization of scale symmetry
International Nuclear Information System (INIS)
Gozzi, E; Mauro, D
2006-01-01
In this paper, we study the symmetry known (Landau and Lifshits 1976 Course of Theoretical Physics vol 1: Mechanics (Oxford: Pergamon)) as mechanical similarity (LMS) and present for any monomial potential. We analyse it in the framework of the Koopman-von Neumann formulation of classical mechanics and prove that in this framework the LMS can be given a canonical implementation. We also show that the LMS is a generalization of the scale symmetry which is present only for the inverse square and a few other potentials. Finally, we study the main obstructions which one encounters in implementing the LMS at the quantum-mechanical level
Problem-Solving Test: The Mechanism of Action of a Human Papilloma Virus Oncoprotein
Szeberenyi, Jozsef
2009-01-01
Terms to be familiar with before you start to solve the test: human papilloma virus; cervical cancer; oncoproteins; malignant transformation; retinoblastoma protein; cell cycle; quiescent and cycling cells; cyclin/cyclin-dependent kinase (Cdk) complexes; E2F; S-phase genes; enhancer element; proto-oncogenes; tumor suppressor genes; radioactive…
Research Projects in Physics: A Mechanism for Teaching Ill-Structured Problem Solving
Milbourne, Jeff; Bennett, Jonathan
2017-01-01
Physics education research has a tradition of studying problem solving, exploring themes such as physical intuition and differences between expert and novice problem solvers. However, most of this work has focused on traditional, or well-structured, problems, similar to what might appear in a textbook. Less work has been done with open-ended, or…
Sugiura, Yoshinori; Sugiura, Tomoko
2015-08-01
While research based on the emotion dysregulation model indicates a positive relationship between intense emotions and generalized anxiety disorder (GAD) symptoms, emotion-focused intervention involves the use of techniques to enhance emotional experiences, based on the notion that GAD patients are engaging in avoidance strategies. To reveal the conditions under which intense emotions lead to reduced GAD symptoms, we designed a longitudinal study to monitor changes in GAD symptoms among students (N = 129) over 3 months. Our focus was on possible moderators of the effect of emotional intensity. Results indicated that when fear of emotions and negative appraisals about problem solving were low, negative emotional intensity reduced later GAD symptoms. Moreover, under the condition of high responsibility to continue thinking, emotional intensity tended to reduce later GAD symptoms. Results suggest that reduced fear of emotions and reduced negative appraisals about problem solving may enhance the use of emotional processing techniques (e.g., emotional exposure). The interaction between responsibility to continue thinking and emotional intensity requires further examination. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Chen, Meixiong; Yuan, Jie; Long, Xingwu; Kang, Zhenglong; Wang, Zhiguo; Li, Yingying
2013-12-01
A general beam position controlling method for 3D optical systems based on the method of solving ray matrix equations has been proposed in this paper. As a typical 3D optical system, nonplanar ring resonator of Zero-Lock Laser Gyroscopes has been chosen as an example to show its application. The total mismatching error induced by Faraday-wedge in nonplanar ring resonator has been defined and eliminated quite accurately with the error less than 1 μm. Compared with the method proposed in Ref. [14], the precision of the beam position controlling has been improved by two orders of magnitude. The novel method can be used to implement automatic beam position controlling in 3D optical systems with servo circuit. All those results have been confirmed by related alignment experiments. The results in this paper are important for beam controlling, ray tracing, cavity design and alignment in 3D optical systems.
Constrained generalized mechanics. The second-order case
International Nuclear Information System (INIS)
Tapia, V.
1985-01-01
The Dirac formalism for constrained systems is developed for systems described by a Lagrangian depending on up to a second-order time derivatives of the generalized co-ordinates (accelerations). It turns out that for a Lagrangian of this kind differing by a total time derivative from a Lagrangian depending on only up to first-order time-derivatives of the generalized co-ordinates (velocities), both classical mechanics at the Lagrangian level are the same; at the Hamiltonian level the two classical mechanics differ conceptually even when the solutions to both sets of Hamiltonian equations of motion are the same
Vibrational mechanics nonlinear dynamic effects, general approach, applications
Blekhman, Iliya I
2000-01-01
This important book deals with vibrational mechanics - the new, intensively developing section of nonlinear dynamics and the theory of nonlinear oscillations. It offers a general approach to the study of the effect of vibration on nonlinear mechanical systems.The book presents the mathematical apparatus of vibrational mechanics which is used to describe such nonlinear effects as the disappearance and appearance under vibration of stable positions of equilibrium and motions (i.e. attractors), the change of the rheological properties of the media, self-synchronization, self-balancing, the vibrat
Solving the cardiac hypertrophy riddle: The angiotensin II-mechanical stress connection.
Zablocki, Daniela; Sadoshima, Junichi
2013-11-08
A series of studies conducted 20 years ago, documenting the cardiac hypertrophy phenotype and its underlying signaling mechanism induced by angiotensin II (Ang II) and mechanical stress, showed a remarkable similarity between the effect of the Gαq agonist and that of mechanical forces on cardiac hypertrophy. Subsequent studies confirmed the involvement of autocrine/paracrine mechanisms, including stretch-induced release of Ang II in load-induced cardiac hypertrophy. Recent studies showed that the Ang II type 1 (AT1) receptor is also directly activated by mechanical forces, suggesting that AT1 receptors play an important role in mediating load-induced cardiac hypertrophy through both ligand- and mechanical stress-dependent mechanisms.
Quantum-mechanical generalization of the Biot-Savart law
International Nuclear Information System (INIS)
Fassio-Canuto, L.
1978-01-01
The complex geometrical considerations involved in deriving the magnetic field due to a current of assigned geometry can be considerably simplified and, therefore, generalized if one employs the field-theoretical relation between the field Asub(μ) and the current jsub(μ). In the general case of a current with helicoidal structure, the magnetic field can be found for any point of space. The particular cases of the loop, the solenoid and the straight wire are then easily derived. The rationale for wanting to generalize the classical Biot-Savart law to include quantum-mechanical effects is discussed in the light of a more general program intended to study the origin of magnetic fields in collapsed objects. (author)
A 'general boundary' formulation for quantum mechanics and quantum gravity
International Nuclear Information System (INIS)
Oeckl, Robert
2003-01-01
I propose to formalize quantum theories as topological quantum field theories in a generalized sense, associating state spaces with boundaries of arbitrary (and possibly finite) regions of space-time. I further propose to obtain such 'general boundary' quantum theories through a generalized path integral quantization. I show how both, non-relativistic quantum mechanics and quantum field theory can be given a 'general boundary' formulation. Surprisingly, even in the non-relativistic case, features normally associated with quantum field theory emerge from consistency conditions. This includes states with arbitrary particle number and pair creation. I also note how three-dimensional quantum gravity is an example for a realization of both proposals and suggest to apply them to four-dimensional quantum gravity
Noncommutative unification of general relativity and quantum mechanics
International Nuclear Information System (INIS)
Heller, Michael; Pysiak, Leszek; Sasin, Wieslaw
2005-01-01
We present a model unifying general relativity and quantum mechanics based on a noncommutative geometry. This geometry is developed in terms of a noncommutative algebra A which is defined on a transformation groupoid Γ given by the action of a noncompact group G on the total space E of a principal fiber bundle over space-time M. The case is important since to obtain physical effects predicted by the model we should assume that G is a Lorentz group or some of its representations. We show that the generalized Einstein equation of the model has the form of the eigenvalue equation for the generalized Ricci operator, and all relevant operators in the quantum sector of the model are random operators; we study their dynamics. We also show that the model correctly reproduces general relativity and the usual quantum mechanics. It is interesting that the latter is recovered by performing the measurement of any observable. In the act of such a measurement the model 'collapses' to the usual quantum mechanics
Generalized Statistical Mechanics at the Onset of Chaos
Directory of Open Access Journals (Sweden)
Alberto Robledo
2013-11-01
Full Text Available Transitions to chaos in archetypal low-dimensional nonlinear maps offer real and precise model systems in which to assess proposed generalizations of statistical mechanics. The known association of chaotic dynamics with the structure of Boltzmann–Gibbs (BG statistical mechanics has suggested the potential verification of these generalizations at the onset of chaos, when the only Lyapunov exponent vanishes and ergodic and mixing properties cease to hold. There are three well-known routes to chaos in these deterministic dissipative systems, period-doubling, quasi-periodicity and intermittency, which provide the setting in which to explore the limit of validity of the standard BG structure. It has been shown that there is a rich and intricate behavior for both the dynamics within and towards the attractors at the onset of chaos and that these two kinds of properties are linked via generalized statistical-mechanical expressions. Amongst the topics presented are: (i permanently growing sensitivity fluctuations and their infinite family of generalized Pesin identities; (ii the emergence of statistical-mechanical structures in the dynamics along the routes to chaos; (iii dynamical hierarchies with modular organization; and (iv limit distributions of sums of deterministic variables. The occurrence of generalized entropy properties in condensed-matter physical systems is illustrated by considering critical fluctuations, localization transition and glass formation. We complete our presentation with the description of the manifestations of the dynamics at the transitions to chaos in various kinds of complex systems, such as, frequency and size rank distributions and complex network images of time series. We discuss the results.
Quantum mechanics vs. general covariance in gravity and string models
International Nuclear Information System (INIS)
Martinec, E.J.
1984-01-01
Quantization of simple low-dimensional systems embodying general covariance is studied. Functional methods are employed in the calculation of effective actions for fermionic strings and 1 + 1 dimensional gravity. The author finds that regularization breaks apparent symmetries of the theory, providing new dynamics for the string and non-trivial dynamics for 1 + 1 gravity. The author moves on to consider the quantization of some generally covariant systems with a finite number of physical degrees of freedom, assuming the existence of an invariant cutoff. The author finds that the wavefunction of the universe in these cases is given by the solution to simple quantum mechanics problems
Generalized Poisson processes in quantum mechanics and field theory
International Nuclear Information System (INIS)
Combe, P.; Rodriguez, R.; Centre National de la Recherche Scientifique, 13 - Marseille; Hoegh-Krohn, R.; Centre National de la Recherche Scientifique, 13 - Marseille; Sirugue, M.; Sirugue-Collin, M.; Centre National de la Recherche Scientifique, 13 - Marseille
1981-01-01
In section 2 we describe more carefully the generalized Poisson processes, giving a realization of the underlying probability space, and we characterize these processes by their characteristic functionals. Section 3 is devoted to the proof of the previous formula for quantum mechanical systems, with possibly velocity dependent potentials and in section 4 we give an application of the previous theory to some relativistic Bose field models. (orig.)
International Nuclear Information System (INIS)
Ates, S; Cataloglu, E
2007-01-01
The purpose of this study was to determine if there are relationships among freshmen/first year students' reasoning abilities, conceptual understandings and problem-solving skills in introductory mechanics. The sample consisted of 165 freshmen science education prospective teachers (female = 86, male = 79; age range 17-21) who were enrolled in an introductory physics course. Data collection was done during the fall semesters in two successive years. At the beginning of each semester, the force concept inventory (FCI) and the classroom test of scientific reasoning (CTSR) were administered to assess students' initial understanding of basic concepts in mechanics and reasoning levels. After completing the course, the FCI and the mechanics baseline test (MBT) were administered. The results indicated that there was a significant difference in problem-solving skill test mean scores, as measured by the MBT, among concrete, formal and postformal reasoners. There were no significant differences in conceptual understanding levels of pre- and post-test mean scores, as measured by FCI, among the groups. The Benferroni post hoc comparison test revealed which set of reasoning levels showed significant difference for the MBT scores. No statistical difference between formal and postformal reasoners' mean scores was observed, while the mean scores between concrete and formal reasoners and concrete and postformal reasoners were statistically significantly different
Quantum mechanics in general relativity and its special - relativistic limit
International Nuclear Information System (INIS)
Tagirov, Eh.A.
1998-01-01
Quantum mechanics of a neutral point-like particle in the general Riemannian space-time is constructed starting with the general Fock representation of the quantum scalar field. The known ambiguity of the representation is removed by the requirement that the quasi-one-particle wave functions in configurational space should admit the Born probabilistic interpretation after a transformation, generally nonlocal, and therefore may be considered as the one-particle wave functions. Operators of momentum and spatial position of a particle acting in the space of these transformed wave functions are deduced consecutively from basic naturally defined operators of the observables in the Fock space. They coincide with the canonical ones only in the case of the infinite velocity of light. In particular, even in the Minkowski space-time and inertial frames of reference , the operators of curvilinear coordinates do not commute
Yuksel, Ibrahim; Ates, Salih
2018-02-01
The purpose of this study is to determine relationship between scientific reasoning and mechanics problem solving skills of students in science education program. Scientific Reasoning Skills Test (SRST) and Basic Mechanics Knowledge Test (BMKT) were applied to 90 second, third and fourth grade students who took Scientific Reasoning Skills course at science teaching program of Gazi Faculty of Education for three successive fall semesters of 2014, 2015 and 2016 academic years. It was found a statistically significant positive (p = 0.038 <0.05) but a low correlation (r = 0.219) between SRST and BMKT. There were no significant relationship among Conservation Laws, Proportional Thinking, Combinational Thinking, Correlational Thinking, Probabilistic Thinking subskills of reasoning and BMKT. There were significant and positive correlation among Hypothetical Thinking and Identifying and Controlling Variables subskills of reasoning and BMKT. The findings of the study were compared with other studies in the field and discussed.
Solved problems in classical mechanics analytical and numerical solutions with comments
de Lange, O L
2010-01-01
Apart from an introductory chapter giving a brief summary of Newtonian and Lagrangian mechanics, this book consists entirely of questions and solutions on topics in classical mechanics that will be encountered in undergraduate and graduate courses. These include one-, two-, and three- dimensional motion; linear and nonlinear oscillations; energy, potentials, momentum, and angular momentum; spherically symmetric potentials; multi-particle systems; rigid bodies; translation androtation of the reference frame; the relativity principle and some of its consequences. The solutions are followed by a set of comments intended to stimulate inductive reasoning and provide additional information of interest. Both analytical and numerical (computer) techniques are used to obtain andanalyze solutions. The computer calculations use Mathematica (version 7), and the relevant code is given in the text. It includes use of the interactive Manipulate function which enables one to observe simulated motion on a computer screen, and...
The statistical mechanics of the classical two-dimensional Coulomb gas is exactly solved
International Nuclear Information System (INIS)
Samaj, L
2003-01-01
The model under consideration is a classical 2D Coulomb gas of pointlike positive and negative unit charges, interacting via a logarithmic potential. In the whole stability range of temperatures, the equilibrium statistical mechanics of this fluid model is exactly solvable via an equivalence with the integrable 2D sine-Gordon field theory. The exact solution includes the bulk thermodynamics, special cases of the surface thermodynamics and the large-distance asymptotic behaviour of the two-body correlation functions
A Hybrid Dynamic Programming for Solving Fixed Cost Transportation with Discounted Mechanism
Farhad Ghassemi Tari
2016-01-01
The problem of allocating different types of vehicles for transporting a set of products from a manufacturer to its depots/cross docks, in an existing transportation network, to minimize the total transportation costs, is considered. The distribution network involves a heterogeneous fleet of vehicles, with a variable transportation cost and a fixed cost in which a discount mechanism is applied on the fixed part of the transportation costs. It is assumed that the number of available vehicles i...
Linear differential equations to solve nonlinear mechanical problems: A novel approach
Nair, C. Radhakrishnan
2004-01-01
Often a non-linear mechanical problem is formulated as a non-linear differential equation. A new method is introduced to find out new solutions of non-linear differential equations if one of the solutions of a given non-linear differential equation is known. Using the known solution of the non-linear differential equation, linear differential equations are set up. The solutions of these linear differential equations are found using standard techniques. Then the solutions of the linear differe...
Galitski, Victor; Kogan, Vladimir; Galitski, Victor Jr
2013-01-01
A series of seminal technological revolutions has led to a new generation of electronic devices miniaturized to such tiny scales where the strange laws of quantum physics come into play. There is no doubt that, unlike scientists and engineers of the past, technology leaders of the future will have to rely on quantum mechanics in their everyday work. This makes teaching and learning the subject of paramount importance for further progress. Mastering quantum physics is a very non-trivial task and its deep understanding can only be achieved through working out real-life problems and examples. It is notoriously difficult to come up with new quantum-mechanical problems that would be solvable with a pencil and paper, and within a finite amount of time. This book remarkably presents some 700+ original problems in quantum mechanics together with detailed solutions covering nearly 1000 pages on all aspects of quantum science. The material is largely new to the English-speaking audience. The problems have been collect...
Macian-Sorribes, Hector; Pulido-Velazquez, Manuel; Tilmant, Amaury
2015-04-01
Stochastic programming methods are better suited to deal with the inherent uncertainty of inflow time series in water resource management. However, one of the most important hurdles in their use in practical implementations is the lack of generalized Decision Support System (DSS) shells, usually based on a deterministic approach. The purpose of this contribution is to present a general-purpose DSS shell, named Explicit Stochastic Programming Advanced Tool (ESPAT), able to build and solve stochastic programming problems for most water resource systems. It implements a hydro-economic approach, optimizing the total system benefits as the sum of the benefits obtained by each user. It has been coded using GAMS, and implements a Microsoft Excel interface with a GAMS-Excel link that allows the user to introduce the required data and recover the results. Therefore, no GAMS skills are required to run the program. The tool is divided into four modules according to its capabilities: 1) the ESPATR module, which performs stochastic optimization procedures in surface water systems using a Stochastic Dual Dynamic Programming (SDDP) approach; 2) the ESPAT_RA module, which optimizes coupled surface-groundwater systems using a modified SDDP approach; 3) the ESPAT_SDP module, capable of performing stochastic optimization procedures in small-size surface systems using a standard SDP approach; and 4) the ESPAT_DET module, which implements a deterministic programming procedure using non-linear programming, able to solve deterministic optimization problems in complex surface-groundwater river basins. The case study of the Mijares river basin (Spain) is used to illustrate the method. It consists in two reservoirs in series, one aquifer and four agricultural demand sites currently managed using historical (XIV century) rights, which give priority to the most traditional irrigation district over the XX century agricultural developments. Its size makes it possible to use either the SDP or
Quantum mechanical analogy for solving a competitive coexistence model in ecology
International Nuclear Information System (INIS)
Wio, H.S.; Kuperman, M.N.; Haeften, B. von
1994-07-01
We have studied an ecological system of three species: a strong and a weak one, competing for a single food resource, modelled as a reaction-diffusion process. An exact analytical solution has been found through a quantum mechanical analogy. Such solution indicates that in certain situations the classical results on extinction and coexistence of Lotka-Volterra type equations are no longer valid, essentially, as a consequence of the weak species mobility. A stability analysis of this solution against changes in different parameters has been carried out. (author). 19 refs, 5 figs
The mechanism of suppression: a component of general comprehension skill.
Gernsbacher, M A; Faust, M E
1991-03-01
We investigated whether the cognitive mechanism of suppression underlies differences in adult comprehension skill. Less skilled comprehenders reject less efficiently the inappropriate meanings of ambiguous words (e.g., the playing card vs. garden tool meaning of spade), the incorrect forms of homophones (e.g., patients vs. patience), the highly typical but absent members of scenes (e.g., a tractor in a farm scene), and words superimposed on pictures or pictures surrounding words. However, less skilled comprehenders are not less cognizant of what is contextually appropriate; in fact, they benefit from a biasing context just as much (and perhaps more) as more skilled comprehenders do. Thus, less skilled comprehenders do not have difficulty enhancing contextually appropriate information. Instead, we suggest that less skilled comprehenders suffer from a less efficient suppression mechanism, which we conclude is an important component of general comprehension skill.
Directory of Open Access Journals (Sweden)
Schuurmans Josien
2009-10-01
Full Text Available Abstract Background Even though depression and anxiety are highly prevalent in adolescence, youngsters are not inclined to seek help in regular healthcare. Therapy through the Internet, however, has been found to appeal strongly to young people. The main aim of the present study is to examine the efficacy of preventive Internet-based guided self-help problem-solving therapy with adolescents reporting depressive and anxiety symptoms. A secondary objective is to test potential mediating and moderating variables in order to gain insight into how the intervention works and for whom it works best. Methods/design This study is a randomized controlled trial with an intervention condition group and a wait-list control group. The intervention condition group receives Internet-based self-help problem-solving therapy. Support is provided by a professional and delivered through email. Participants in the wait-list control group receive the intervention four months later. The study population consists of adolescents (12-18-year-olds from the general population who report mild to moderate depressive and/or anxiety symptoms and are willing to complete a self-help course. Primary outcomes are symptoms of depression and anxiety. Secondary outcomes are quality of life, social anxiety, and cost-effectiveness. The following variables are examined for their moderating role: demographics, motivation, treatment credibility and expectancy, externalizing behaviour, perceived social support from parents and friends, substance use, the experience of important life events, physical activity, the quality of the therapeutic alliance, and satisfaction. Mediator variables include problem-solving skills, worrying, mastery, and self-esteem. Data are collected at baseline and at 3 weeks, 5 weeks, 4 months, 8 months, and 12 months after baseline. Both intention-to-treat and completer analyses will be conducted. Discussion This study evaluates the efficacy and mechanisms of
Directory of Open Access Journals (Sweden)
Mustafa Bayram
2017-01-01
Full Text Available In this study, we have applied a generalized successive numerical technique to solve the elasticity problem of based on the elastic ground with variable coefficient. In the first stage, we have calculated the generalized successive approximation of being given BVP and in the second stage we have transformed it into Padé series. At the end of study a test problem has been given to clarify the method.
Mainert, Jakob; Kretzschmar, André; Neubert, Jonas C.; Greiff, Samuel
2015-01-01
Transversal skills, such as complex problem solving (CPS) are viewed as central twenty-first-century skills. Recent empirical findings have already supported the importance of CPS for early academic advancement. We wanted to determine whether CPS could also contribute to the understanding of career advancement later in life. Towards this end, we…
Mashood, K. K.; Singh, Vijay A.
2013-01-01
Research suggests that problem-solving skills are transferable across domains. This claim, however, needs further empirical substantiation. We suggest correlation studies as a methodology for making preliminary inferences about transfer. The correlation of the physics performance of students with their performance in chemistry and mathematics in…
A κ-generalized statistical mechanics approach to income analysis
International Nuclear Information System (INIS)
Clementi, F; Gallegati, M; Kaniadakis, G
2009-01-01
This paper proposes a statistical mechanics approach to the analysis of income distribution and inequality. A new distribution function, having its roots in the framework of κ-generalized statistics, is derived that is particularly suitable for describing the whole spectrum of incomes, from the low–middle income region up to the high income Pareto power-law regime. Analytical expressions for the shape, moments and some other basic statistical properties are given. Furthermore, several well-known econometric tools for measuring inequality, which all exist in a closed form, are considered. A method for parameter estimation is also discussed. The model is shown to fit remarkably well the data on personal income for the United States, and the analysis of inequality performed in terms of its parameters is revealed as very powerful
The problem of time quantum mechanics versus general relativity
Anderson, Edward
2017-01-01
This book is a treatise on time and on background independence in physics. It first considers how time is conceived of in each accepted paradigm of physics: Newtonian, special relativity, quantum mechanics (QM) and general relativity (GR). Substantial differences are moreover uncovered between what is meant by time in QM and in GR. These differences jointly source the Problem of Time: Nine interlinked facets which arise upon attempting concurrent treatment of the QM and GR paradigms, as is required in particular for a background independent theory of quantum gravity. A sizeable proportion of current quantum gravity programs - e.g. geometrodynamical and loop quantum gravity approaches to quantum GR, quantum cosmology, supergravity and M-theory - are background independent in this sense. This book's foundational topic is thus furthermore of practical relevance in the ongoing development of quantum gravity programs. This book shows moreover that eight of the nine facets of the Problem of Time already occur upon ...
A κ-generalized statistical mechanics approach to income analysis
Clementi, F.; Gallegati, M.; Kaniadakis, G.
2009-02-01
This paper proposes a statistical mechanics approach to the analysis of income distribution and inequality. A new distribution function, having its roots in the framework of κ-generalized statistics, is derived that is particularly suitable for describing the whole spectrum of incomes, from the low-middle income region up to the high income Pareto power-law regime. Analytical expressions for the shape, moments and some other basic statistical properties are given. Furthermore, several well-known econometric tools for measuring inequality, which all exist in a closed form, are considered. A method for parameter estimation is also discussed. The model is shown to fit remarkably well the data on personal income for the United States, and the analysis of inequality performed in terms of its parameters is revealed as very powerful.
Statistical mechanics of sparse generalization and graphical model selection
International Nuclear Information System (INIS)
Lage-Castellanos, Alejandro; Pagnani, Andrea; Weigt, Martin
2009-01-01
One of the crucial tasks in many inference problems is the extraction of an underlying sparse graphical model from a given number of high-dimensional measurements. In machine learning, this is frequently achieved using, as a penalty term, the L p norm of the model parameters, with p≤1 for efficient dilution. Here we propose a statistical mechanics analysis of the problem in the setting of perceptron memorization and generalization. Using a replica approach, we are able to evaluate the relative performance of naive dilution (obtained by learning without dilution, following by applying a threshold to the model parameters), L 1 dilution (which is frequently used in convex optimization) and L 0 dilution (which is optimal but computationally hard to implement). Whereas both L p diluted approaches clearly outperform the naive approach, we find a small region where L 0 works almost perfectly and strongly outperforms the simpler to implement L 1 dilution
Thallium Toxicity: General Issues, Neurological Symptoms, and Neurotoxic Mechanisms.
Osorio-Rico, Laura; Santamaria, Abel; Galván-Arzate, Sonia
2017-01-01
Thallium (Tl + ) is a ubiquitous natural trace metal considered as the most toxic among heavy metals. The ionic ratio of Tl + is similar to that of potassium (K + ), therefore accounting for the replacement of the latter during enzymatic reactions. The principal organelle damaged after Tl + exposure is mitochondria. Studies on the mechanisms of Tl + include intrinsic pathways altered and changes in antiapoptotic and proapoptotic proteins, cytochrome c, and caspases. Oxidative damage pathways increase after Tl + exposure to produce reactive oxygen species (ROS), changes in physical properties of the cell membrane caused by lipid peroxidation, and concomitant activation of antioxidant mechanisms. These processes are likely to account for the neurotoxic effects of the metal. In humans, Tl + is absorbed through the skin and mucous membranes and then is widely distributed throughout the body to be accumulated in bones, renal medulla, liver, and the Central Nervous System. Given the growing relevance of Tl + intoxication, in recent years there is a notorious increase in the number of reports attending Tl + pollution in different countries. In this sense, the neurological symptoms produced by Tl + and its neurotoxic effects are gaining attention as they represent a serious health problem all over the world. Through this review, we present an update to general information about Tl + toxicity, making emphasis on some recent data about Tl + neurotoxicity, as a field requiring attention at the clinical and preclinical levels.
Multiple-event probability in general-relativistic quantum mechanics
International Nuclear Information System (INIS)
Hellmann, Frank; Mondragon, Mauricio; Perez, Alejandro; Rovelli, Carlo
2007-01-01
We discuss the definition of quantum probability in the context of 'timeless' general-relativistic quantum mechanics. In particular, we study the probability of sequences of events, or multievent probability. In conventional quantum mechanics this can be obtained by means of the 'wave function collapse' algorithm. We first point out certain difficulties of some natural definitions of multievent probability, including the conditional probability widely considered in the literature. We then observe that multievent probability can be reduced to single-event probability, by taking into account the quantum nature of the measuring apparatus. In fact, by exploiting the von-Neumann freedom of moving the quantum/classical boundary, one can always trade a sequence of noncommuting quantum measurements at different times, with an ensemble of simultaneous commuting measurements on the joint system+apparatus system. This observation permits a formulation of quantum theory based only on single-event probability, where the results of the wave function collapse algorithm can nevertheless be recovered. The discussion also bears on the nature of the quantum collapse
Statistical mechanics of learning orthogonal signals for general covariance models
International Nuclear Information System (INIS)
Hoyle, David C
2010-01-01
Statistical mechanics techniques have proved to be useful tools in quantifying the accuracy with which signal vectors are extracted from experimental data. However, analysis has previously been limited to specific model forms for the population covariance C, which may be inappropriate for real world data sets. In this paper we obtain new statistical mechanical results for a general population covariance matrix C. For data sets consisting of p sample points in R N we use the replica method to study the accuracy of orthogonal signal vectors estimated from the sample data. In the asymptotic limit of N,p→∞ at fixed α = p/N, we derive analytical results for the signal direction learning curves. In the asymptotic limit the learning curves follow a single universal form, each displaying a retarded learning transition. An explicit formula for the location of the retarded learning transition is obtained and we find marked variation in the location of the retarded learning transition dependent on the distribution of population covariance eigenvalues. The results of the replica analysis are confirmed against simulation
A damage mechanics based general purpose interface/contact element
Yan, Chengyong
Most of the microelectronics packaging structures consist of layered substrates connected with bonding materials, such as solder or epoxy. Predicting the thermomechanical behavior of these multilayered structures is a challenging task in electronic packaging engineering. In a layered structure the most complex part is always the interfaces between the strates. Simulating the thermo-mechanical behavior of such interfaces, is the main theme of this dissertation. The most commonly used solder material, Pb-Sn alloy, has a very low melting temperature 180sp°C, so that the material demonstrates a highly viscous behavior. And, creep usually dominates the failure mechanism. Hence, the theory of viscoplasticity is adapted to describe the constitutive behavior. In a multilayered assembly each layer has a different coefficient of thermal expansion. Under thermal cycling, due to heat dissipated from circuits, interfaces and interconnects experience low cycle fatigue. Presently, the state-of-the art damage mechanics model used for fatigue life predictions is based on Kachanov (1986) continuum damage model. This model uses plastic strain as a damage criterion. Since plastic strain is a stress path dependent value, the criterion does not yield unique damage values for the same state of stress. In this dissertation a new damage evolution equation based on the second law of thermodynamic is proposed. The new criterion is based on the entropy of the system and it yields unique damage values for all stress paths to the final state of stress. In the electronics industry, there is a strong desire to develop fatigue free interconnections. The proposed interface/contact element can also simulate the behavior of the fatigue free Z-direction thin film interconnections as well as traditional layered interconnects. The proposed interface element can simulate behavior of a bonded interface or unbonded sliding interface, also called contact element. The proposed element was verified against
GENERAL EQUATIONS OF CARBONIZATION OF EUCALYPTUS SPP KINETIC MECHANISMS
Directory of Open Access Journals (Sweden)
Túlio Jardim Raad
2006-06-01
Full Text Available In the present work, a set of general equations related to kinetic mechanism of wood compound carbonization: hemicelluloses, cellulose and lignin was obtained by Avrami-Eroffev and Arrhenius equations and Thermogravimetry of Eucalyptus cloeziana, Eucalyptus camaldulensis, Corymbia citriodora, Eucalyptus urophylla and Eucalyptus grandis samples, TG-Isothermal and TG-Dynamic. The different thermal stabilities and decomposition temperature bands of those species compounds were applied as strategy to obtain the kinetic parameters: activation energy, exponential factor and reaction order. The kinetic model developed was validated by thermogravimetric curves from carbonization of others biomass such as coconut. The kinetic parameters found were - Hemicelluloses: E=98,6 kJmol, A=3,5x106s-1 n=1,0; - Cellulose: E=182,2 kJmol, A=1,2x1013s-1 n=1,5; - Lignin: E=46,6 kJmol, A=2,01s-1 n=0,41. The set of equations can be implemented in a mathematical model of wood carbonization simulation (with heat and mass transfer equations with the aim of optimizing the control and charcoal process used to produce pig iron.
General aspects of solid on liquid growth mechanisms
International Nuclear Information System (INIS)
Laux, E; Charmet, J; Haquette, H; Banakh, O; Jeandupeux, L; Graf, B; Keppner, H
2009-01-01
Liquids, in general, tend to have a lower density as solids and therefore it is not straightforward to deposit solid over liquids in a way that the liquid becomes hermetically sealed under the solid layer. The authors review that several phenomena that can easily be observed in nature are only due to particular anomalies and solid on liquid is rather an exception as the rule. Natural solid on liquid systems are lacking of thermal, mechanical or chemical stability. It is not surprising, that one is not at all used thinking about to e.g. replace the gate oxide in a thin film transistor by a thin film of oil, or, to find in other microsystems functional liquids between a stack of thin solid films. However, once this becomes a serious option, a large variety of new Microsystems with new functionalities can be easily designed. In another paper (this conference and [1]) the authors pioneered that the polymer Parylene (poly(p-xylylene)) can be deposited on liquids coming already quite close to the above mentioned vision. In this paper the authors ask if one can synthesize other solid on liquid systems and surprisingly conclude, based on experimental evidence, that solid on liquid deposition seems to rather be the rule and not the exception.
One interpretation for both Quantum Mechanics and General Relativity
Energy Technology Data Exchange (ETDEWEB)
Halewijn, Ewoud
2014-07-01
In reconciling General Relativity with Quantum Mechanics, it is challenging to resolve the combined mathematical equations and to find an interpretation that makes sense ontologically. Such an interpretation has been developed by quantizing descriptive components in both the theories and other views. The resulting micro-components have been re-integrated within the scope of known gaps between science and 'the real world'. The odd peculiarities in these theories have been made look 'normal' by fully untraditionally answering fundamental questions. The interpretation is suggesting that we define time as a discrete operator and its eigenvalues as constraints on space-time manifolds, in order to reconcile the mathematical equations. Outside the mathematical arena we suggest reconsidering the concepts of Black Holes, the Big Bang, the epistemological problem of perception in philosophy and the supposed clash between scientific and the spiritual worldviews. It is concluded that developing one consistent ontological interpretation for both theorie is possible. It is a weird story, but it is making powerful suggestions for reviewing some of our fundamental convictions.
Blackburn, J. Joey; Robinson, J. Shane; Lamm, Alexa J.
2014-01-01
The purpose of this experimental study was to determine the effects of cognitive style and problem complexity on Oklahoma State University preservice agriculture teachers' (N = 56) ability to solve problems in small gasoline engines. Time to solution was operationalized as problem solving ability. Kirton's Adaption-Innovation Inventory was…
Vanhamäki, Heikki; Amm, Olaf; Fujii, Ryo; Yoshikawa, Aki; Ieda, Aki
2013-04-01
The Cowling mechanism is characterized by the generation of polarization space charges in the ionosphere in consequence of a partial or total blockage of FAC flowing between the ionosphere and the magnetosphere. Thus a secondary polarization electric field builds up in the ionosphere, which guarantees that the whole (primary + secondary) ionospheric current system is again in balance with the FAC. In the Earth's ionosphere the Cowling mechanism is long known to operate in the equatorial electrojet, and several studies indicate that it is important also in auroral current systems. We present a general method for calculate the secondary polarization electric field, when the ionospheric conductances, the primary (modeled) or the total (measured) electric field, and the Cowling efficiency are given. Here the Cowling efficiency is defined as the fraction of the divergent Hall current canceled by secondary Pedersen current. In contrast to previous studies, our approach is a general solution which is not limited to specific geometrical setups (like an auroral arc), and all parameters may have any kind of spatial dependence. The solution technique is based on spherical elementary current (vector) systems (SECS). This way, we avoid the need to specify explicit boundary conditions for the searched polarization electric field or its potential, which would be required if the problem was solved in a differential equation approach. Instead, we solve an algebraic matrix equation, for which the implicit boundary condition that the divergence of the polarization electric field vanishes outside our analysis area is sufficient. In order to illustrate the effect of Cowling mechanism on ionospheric current systems, we apply our method to two simple models of auroral electrodynamic situations: 1) a mesoscale strong conductance enhancement in the early morning sector within a relatively weak southward primary electric field, 2) a morning sector auroral arc with only a weak conductance
General relativistic continuum mechanics and the post-Newtonian equations of motion
International Nuclear Information System (INIS)
Morrill, T.H.
1991-01-01
Aspects are examined of general relativistic continuum mechanics. Perfectly elastic materials are dealt with but not exclusively. The derivation of their equations of motion is emphasized, in the post-Newtonian approximation. A reformulation is presented based on the tetrad formalism, of Carter and Quintana's theory of general relativistic elastic continua. A field Lagrangian is derived describing perfect material media; show that the usual covariant conservations law for perfectly elastic media is fully equivalent to the Euler-Lagrange equations describing these same media; and further show that the equations of motion for such materials follow directly from Einstein's field equations. In addition, a version of this principle shows that the local mass density in curved space-time partially depends on the amount and distribution of mass energy in the entire universe and is related to the mass density that would occur if space-time were flat. The total Lagrangian was also expanded in an EIH (Einstein, Infeld, Hoffmann) series to obtain a total post-Newtonian Lagrangian. The results agree with those found by solving Einstein's equations for the metric coefficients and by deriving the post-Newtonian equations of motion from the covariant conservation law
Nonequilibrium statistical mechanics in the general theory of relativity. I. A general formalism
International Nuclear Information System (INIS)
Israel, W.; Kandrup, H.E.
1984-01-01
This is the first in a series of papers, the overall objective of which is the formulation of a new covariant approach to nonequilibrium statistical mechanics in classical general relativity. The objecct here is the development of a tractable theory for self-gravitating systems. It is argued that the ''state'' of an N-particle system may be characterized by an N-particle distribution function, defined in an 8N-dimensional phase space, which satisfies a collection of N conservation equations. By mapping the true physics onto a fictitious ''background'' spacetime, which may be chosen to satisfy some ''average'' field equations, one then obtains a useful covariant notion of ''evolution'' in response to a fluctuating ''gravitational force.'' For many cases of practical interest, one may suppose (i) that these fluctuating forces satisfy linear field equations and (ii) that they may be modeled by a direct interaction. In this case, one can use a relativistic projection operator formalism to derive exact closed equations for the evolution of such objects as an appropriately defined reduced one-particle distribution function. By capturing, in a natural way, the notion of a dilute gas, or impulse, approximation, one is then led to a comparatively simple equation for the one-particle distribution. If, furthermore, one treats the effects of the fluctuating forces as ''localized'' in space and time, one obtains a tractable kinetic equation which reduces, in the Newtonian limit, to the stardard Landau equation
International Nuclear Information System (INIS)
Stancic, V.
2001-01-01
This paper presents some elements of a new approach to solve analytically the linearized three-dimensional (3-D) transport equation of neutral particles. Since this task is of such special importance, we present some results of a paper that is still in progress. The most important is that using this transformation, an integro-differential equation with an analytical solution is obtained. For this purpose, a simplest 3-D equation is being considered which describes the transport process in an infinite medium. Until now, this equation has been analytically considered either using the Laplace transform with respect to time parameter t or applying the Fourier transform over the space coordinate. Both of them reduce the number of differential terms in the equation; however, evaluation of the inverse transformation is complicated. In this paper, we introduce for the first time a Fourier transform induced by the Boltzmann operator. For this, we use a complete set of 3-D eigenfunctions of the Boltzmann transport operator defined in a similar way as those that have been already used in 3-D transport theory as a basic set to transform the transport equation. This set consists of a continuous part and a discrete one with spectral measure. The density distribution equation shows the known form asymptotic behavior. Several applications are to be performed using this equation and compared to the benchmark one. Such an analysis certainly would be out of the available space
General aspects of the mechanical integrity of canisters
International Nuclear Information System (INIS)
Saario, Timo
2007-01-01
This paper attempts to introduce a new point of view to the mechanical integrity of the canisters, 'mechanical integrity evolutionary path'. The mechanical integrity evolutionary path is a description of development of the critical parameters involved in the prevailing degradation modes as a function of time. The degradation mechanisms considered are: mechanical overload; creep; and stress corrosion cracking. For each degradation mechanism one may consider two different states; initial state; critical state. The initial state considered will be different for different degradation mechanisms. For example stress corrosion cracking (SCC), which involves electrochemical steps is not possible without a surface covering aqueous phase. Thus, potentially, the initial state for SCC is that existing after saturation. On the other hand, the initial state for a possible mechanical overload can be different in different periods during the mechanical integrity evolutionary path. During the handling and transport stages the initial state is 'ex works', while during a glaciation the initial state has been altered due to creep, corrosion and possible SCC processes. The canister will go through mechanical overload during saturation and bentonite swelling phases and it will deform to fit the form of the insert. The initial state for this period is 'ex works', with e.g. manufacturing defects. The insert is designed to bear the load after closing the gap. In the 'ex works' state directionality of the mechanical properties has been raised lately as a new issue worth checking. Within the projected evolutionary path two events have been especially considered; seismic events and glaciation. A glacier 2 km thick would increase the hydrostatic pressure with 20 MPa if there were a mechanism transmitting the load into the aqueous phase. Remembering what makes ice skating possible such a mechanism seems plausible. For mechanical overload the critical state is relatively straightforward to
General aspects of the mechanical integrity of canisters
Energy Technology Data Exchange (ETDEWEB)
Saario, Timo [VTT Materials and Building (Finland)
2007-09-15
This paper attempts to introduce a new point of view to the mechanical integrity of the canisters, 'mechanical integrity evolutionary path'. The mechanical integrity evolutionary path is a description of development of the critical parameters involved in the prevailing degradation modes as a function of time. The degradation mechanisms considered are: mechanical overload; creep; and stress corrosion cracking. For each degradation mechanism one may consider two different states; initial state; critical state. The initial state considered will be different for different degradation mechanisms. For example stress corrosion cracking (SCC), which involves electrochemical steps is not possible without a surface covering aqueous phase. Thus, potentially, the initial state for SCC is that existing after saturation. On the other hand, the initial state for a possible mechanical overload can be different in different periods during the mechanical integrity evolutionary path. During the handling and transport stages the initial state is 'ex works', while during a glaciation the initial state has been altered due to creep, corrosion and possible SCC processes. The canister will go through mechanical overload during saturation and bentonite swelling phases and it will deform to fit the form of the insert. The initial state for this period is 'ex works', with e.g. manufacturing defects. The insert is designed to bear the load after closing the gap. In the 'ex works' state directionality of the mechanical properties has been raised lately as a new issue worth checking. Within the projected evolutionary path two events have been especially considered; seismic events and glaciation. A glacier 2 km thick would increase the hydrostatic pressure with 20 MPa if there were a mechanism transmitting the load into the aqueous phase. Remembering what makes ice skating possible such a mechanism seems plausible. For mechanical overload the critical
Generalized contexts and consistent histories in quantum mechanics
International Nuclear Information System (INIS)
Losada, Marcelo; Laura, Roberto
2014-01-01
We analyze a restriction of the theory of consistent histories by imposing that a valid description of a physical system must include quantum histories which satisfy the consistency conditions for all states. We prove that these conditions are equivalent to imposing the compatibility conditions of our formalism of generalized contexts. Moreover, we show that the theory of consistent histories with the consistency conditions for all states and the formalism of generalized context are equally useful representing expressions which involve properties at different times
Alhusaini, Abdulnasser Alashaal F.
The Real Engagement in Active Problem Solving (REAPS) model was developed in 2004 by C. June Maker and colleagues as an intervention for gifted students to develop creative problem solving ability through the use of real-world problems. The primary purpose of this study was to examine the effects of the REAPS model on developing students' general creativity and creative problem solving in science with two durations as independent variables. The long duration of the REAPS model implementation lasted five academic quarters or approximately 10 months; the short duration lasted two quarters or approximately four months. The dependent variables were students' general creativity and creative problem solving in science. The second purpose of the study was to explore which aspects of creative problem solving (i.e., generating ideas, generating different types of ideas, generating original ideas, adding details to ideas, generating ideas with social impact, finding problems, generating and elaborating on solutions, and classifying elements) were most affected by the long duration of the intervention. The REAPS model in conjunction with Amabile's (1983; 1996) model of creative performance provided the theoretical framework for this study. The study was conducted using data from the Project of Differentiation for Diverse Learners in Regular Classrooms (i.e., the Australian Project) in which one public elementary school in the eastern region of Australia cooperated with the DISCOVER research team at the University of Arizona. All students in the school from first to sixth grade participated in the study. The total sample was 360 students, of which 115 were exposed to a long duration and 245 to a short duration of the REAPS model. The principal investigators used a quasi-experimental research design in which all students in the school received the treatment for different durations. Students in both groups completed pre- and posttests using the Test of Creative Thinking
Generalized statistical mechanics approaches to earthquakes and tectonics
Papadakis, Giorgos; Michas, Georgios
2016-01-01
Despite the extreme complexity that characterizes the mechanism of the earthquake generation process, simple empirical scaling relations apply to the collective properties of earthquakes and faults in a variety of tectonic environments and scales. The physical characterization of those properties and the scaling relations that describe them attract a wide scientific interest and are incorporated in the probabilistic forecasting of seismicity in local, regional and planetary scales. Considerable progress has been made in the analysis of the statistical mechanics of earthquakes, which, based on the principle of entropy, can provide a physical rationale to the macroscopic properties frequently observed. The scale-invariant properties, the (multi) fractal structures and the long-range interactions that have been found to characterize fault and earthquake populations have recently led to the consideration of non-extensive statistical mechanics (NESM) as a consistent statistical mechanics framework for the description of seismicity. The consistency between NESM and observations has been demonstrated in a series of publications on seismicity, faulting, rock physics and other fields of geosciences. The aim of this review is to present in a concise manner the fundamental macroscopic properties of earthquakes and faulting and how these can be derived by using the notions of statistical mechanics and NESM, providing further insights into earthquake physics and fault growth processes. PMID:28119548
General presentation of the core mechanical behaviour approach in France
International Nuclear Information System (INIS)
Bernard, A.; Dorsselaere, J.P. van
1984-01-01
This French review paper presents the evolution along time of the FBR core mechanical behaviour approach, from RAPSODIE to SPX2, through PHENIX and SPX1: core designs, knowledge of the irradiation laws, project criterias, calculation codes, and R and D fields. (author)
Directory of Open Access Journals (Sweden)
Leonova O.I.,
2014-11-01
Full Text Available At the moment the question of how to create and maintain the psychological safety of the educational environment of the school is not sufficiently studied. Meanwhile, there has been proved its positive effect on the psychological health of students, their emotional and personal well-being, the formation of a meta-subjective and personal educational outcomes. This paper describes a study the purpose of which was to examine and verify empiricaly the features of management activities in the educational organization to create a psychologically safe learning environment. We studied personality traits of the Head of an educational organization by the procedure "Troubleshooting leadership abilities" (E. Zharikova, E. Krushelnytsky, techniques "Diagnosis of the level of burnout" (V.V. Boyko, methods of self-management style assessment (A.V. Agrashenkova, modified by E.P. Ilyin, and methods for rapid assessment of health, activity, mood (SAN. We proposed mechanisms to solve the problem of creating a comfortable and safe learning environment in the educational organization of general education
Generalized space and linear momentum operators in quantum mechanics
International Nuclear Information System (INIS)
Costa, Bruno G. da; Borges, Ernesto P.
2014-01-01
We propose a modification of a recently introduced generalized translation operator, by including a q-exponential factor, which implies in the definition of a Hermitian deformed linear momentum operator p ^ q , and its canonically conjugate deformed position operator x ^ q . A canonical transformation leads the Hamiltonian of a position-dependent mass particle to another Hamiltonian of a particle with constant mass in a conservative force field of a deformed phase space. The equation of motion for the classical phase space may be expressed in terms of the generalized dual q-derivative. A position-dependent mass confined in an infinite square potential well is shown as an instance. Uncertainty and correspondence principles are analyzed
The Mechanism of Suppression: A Component of General Comprehension Skill
Gernsbacher, Morton Ann; Faust, Mark E.
1991-01-01
We investigated whether the cognitive mechanism of suppression underlies differences in adult comprehension skill. Less skilled comprehenders reject less efficiently the inappropriate meanings of ambiguous words (e.g., the playing card vs. garden tool meaning of spade), the incorrect forms of homophones (e.g., patients vs. patience), the highly typical but absent members of scenes (e.g., a tractor in a farm scene), and words superimposed on pictures or pictures surrounding words. However, les...
Corrosion resistance of zirconium: general mechanisms, behaviour in nitric acid
International Nuclear Information System (INIS)
Pinard Legry, G.
1990-01-01
Corrosion resistance of zirconium results from the strong affinity of this metal for oxygen; as a result a thin protective oxide film is spontaneously formed in air or aqueous media, its thickness and properties depending on the physicochemical conditions at the interface. This film passivates the underlying metal but obviously if the passive film is partially or completely removed, localised or generalised corrosion phenomena will occur. In nitric acid, this depassivation may be chemical (fluorides) or mechanical (straining, creep, fretting). In these cases it is useful to determine the physicochemical conditions (concentration, temperature, potential, stress) which will have to be observed to use safely zirconium and its alloys in nitric acid solutions [fr
Davidson's generalization of the Fenyes-Nelson stochastic model of quantum mechanics
International Nuclear Information System (INIS)
Shucker, D.S.
1980-01-01
Davidson's generalization of the Fenyes-Nelson stochastic model of quantum mechanics is discussed. It is shown that this author's previous results concerning the Fenyes-Nelson process extend to the more general theory of Davidson. (orig.)
Decaying states as complex energy eigenvectors in generalized quantum mechanics
International Nuclear Information System (INIS)
Sudarshan, E.C.G.; Chiu, C.B.; Gorini, V.
1977-04-01
The problem of particle decay is reexamined within the Hamiltonian formalism. By deforming contours of integration, the survival amplitude is expressed as a sum of purely exponential contributions arising from the simple poles of the resolvent on the second sheet plus a background integral along a complex contour GAMMA running below the location of the poles. One observes that the time dependence of the survival amplitude in the small time region is strongly correlated to the asymptotic behaviour of the energy spectrum of the system; one computes the small time behavior of the survival amplitude for a wide variety of asymptotic behaviors. In the special case of the Lee model, using a formal procedure of analytic continuation, it is shown that a complete set of complex energy eigenvectors of the Hamiltonian can be associated with the poles of the resolvent of the background contour GAMMA. These poles and points along GAMMA correspond to the discrete and the continuum states respectively. In this context, each unstable particle is associated with a well defined object, which is a discrete generalized eigenstate of the Hamiltonian having a complex eigenvalue, with its real and negative imaginary parts being the mass and half width of the particle respectively. Finally, one briefly discusses the analytic continuation of the scattering amplitude within this generalized scheme, and notes the appearance of ''redundant poles'' which do not correspond to discrete solutions of the modified eigenvalue problem
General-relativistic celestial mechanics. II. Translational equations of motion
International Nuclear Information System (INIS)
Damour, T.; Soffel, M.; Xu, C.
1992-01-01
The translational laws of motion for gravitationally interacting systems of N arbitrarily composed and shaped, weakly self-gravitating, rotating, deformable bodies are obtained at the first post-Newtonian approximation of general relativity. The derivation uses our recently introduced multi-reference-system method and obtains the translational laws of motion by writing that, in the local center-of-mass frame of each body, relativistic inertial effects combine with post-Newtonian self- and externally generated gravitational forces to produce a global equilibrium (relativistic generalization of d'Alembert's principle). Within the first post-Newtonian approximation [i.e., neglecting terms of order (v/c) 4 in the equations of motion], our work is the first to obtain complete and explicit results, in the form of infinite series, for the laws of motion of arbitrarily composed and shaped bodies. We first obtain the laws of motion of each body as an infinite series exhibiting the coupling of all the (Blanchet-Damour) post-Newtonian multipole moments of this body to the post-Newtonian tidal moments (recently defined by us) felt by this body. We then give the explicit expression of these tidal moments in terms of post-Newtonian multipole moments of the other bodies
Is there a relativistic nonlinear generalization of quantum mechanics?
Energy Technology Data Exchange (ETDEWEB)
Elze, Hans-Thomas [Dipartimento di Fisica ' Enrico Fermi' , Largo Pontecorvo 3, I-56127 Pisa (Italy)
2007-05-15
Yes, there is. - A new kind of gauge theory is introduced, where the minimal coupling and corresponding covariant derivatives are defined in the space of functions pertaining to the functional Schroedinger picture of a given field theory. While, for simplicity, we study the example of a U(1) symmetry, this kind of gauge theory can accommodate other symmetries as well. We consider the resulting relativistic nonlinear extension of quantum mechanics and show that it incorporates gravity in the (0+1)-dimensional limit, where it leads to the Schroedinger-Newton equations. Gravity is encoded here into a universal nonlinear extension of quantum theory. The probabilistic interpretation, i.e. Born's rule, holds provided the underlying model has only dimensionless parameters.
Study of General health, resiliency, and defense mechanisms in patients with migraine headache
Directory of Open Access Journals (Sweden)
Alireza Aghayusefi
2013-06-01
Full Text Available Background: Migraine is a neurological disease that the etiology, several factors affect its onset or its exacerbation. One of the factors affecting disease is psychological factors such as defense mechanisms, resiliency, and general health. This study assessed the relationship between general health, resiliency, and general defense mechanisms, and also predicts the general health of people with migraine headaches that have a high resiliency and use mature defense mechanisms. Material and Methods: 50 women with migraine headache in the city of Bushehr using defense mechanisms, resiliency, and general health questionnaires were studied. For statistical analysis, Pearson correlation and multiple regression tests were used by SPSS 17 software. Results: The results showed that most of the defense mechanisms of migraine sufferers are Immature and Neuroticism. There is significant negative correlation between the deterioration of general health and resiliency as well as the mature defense mechanism (p=0/003, and also there is a significant positive correlation between this deterioration with neuroticism (p=0/040 and immature defense mechanisms (p=0/041. On the other hand there is significant negative correlation between resiliencies with immature (p=0/009 and neuroticism defense mechanisms (p=0/04, and also with mature defense mechanism has a significant positive correlation (p=0/003. Also, as more people use the mature defense mechanism, their deterioration of general health will be reduced, but this relationship will be stronger with the presence of resiliency. So migraine people use the mature defense mechanisms with high resiliency will have more favorable general health (less deterioration of general health. Conclusion: This study showed that migraine patients use the mature defense mechanisms with high resiliency will have more favorable general health (less deterioration of general health.
Yarbus's Conceptions on the General Mechanisms of Color Perception.
Nikolaev, Petr P; Rozhkova, Galina I
2015-01-01
In the last series of papers published during 1975 to 1980, Alfred Yarbus tried to formulate general conceptions concerning the basic principles of retinal image processing in the human visual system. The original ideas of Yarbus were based on the results of his numerous and various experiments carried out with extraordinary inventiveness and great skill. Being concentrated primarily on the problems of color vision, Alfred Yarbus dreamed of elaborating a comprehensive model that would simulate visual information processing at the monocular precognitive level in the visual system of humans with normal trichromatic color perception. In this article, the most important of Yarbus' experimental paradigms, findings, statements, and conclusions are systematized and considered in relation to the classical theories of color perception and, in particular, fundamental theses of the Nyberg school. The perceptual model developed by Alfred Yarbus remained incomplete. Nevertheless, it is already evident that some intrinsic contradictions make it inadequate in terms of comprehensive modeling. However, certain partial advantages deserve more thorough appreciation and further investigation. © The Author(s) 2015.
GENERAL MECHANISMS OF CITATION SYSTEM OF SCIENTIFIC ARTICLES
Directory of Open Access Journals (Sweden)
Віктор Дмитрович ГОГУНСЬКИЙ
2016-02-01
Full Text Available Transformation competitive environment of higher education in the creation of effective mechanisms of management research encourages research teams and individual researchers to analyze their activity Publication search methods for improvement of citations of scientific publications. The paper analyzed the life cycle of scientific publications and show that the way to promote scientific articles in the world community inherent properties of Markov processes. Application of Markov chains allows top ground the need for active participation of the authors in the distribution of its publications in different scientometric databases, repositories of scientific and social networks. Markov model to describe decomposition of scientists made certain discrete states and proposed a schematic diagram of transitions between them. The model's 5A fully reflect the properties of the system. Communication influences the probability of changing system states with consistent movement along the trajectory from a lack of information about the publication to familiarize with it because of the positive attitude to state its citation. This is a must as well as a negative attitude to the publications. Proved that improve performance citation of scientific publications in the case of using Google Scholar, ORCID, Mendeley, Academia, ResearchGate, and others. The active participation of authors in their publications available in these systems leads to an increase in the proportion of articles that are available to colleagues in the global scientific community that is becoming one of the factors of increase in citations.
The avian egg exhibits general allometric invariances in mechanical design.
Juang, Jia-Yang; Chen, Pin-Yi; Yang, Da-Chang; Wu, Shang-Ping; Yen, An; Hsieh, Hsin-I
2017-10-27
The avian egg exhibits extraordinary diversity in size, shape and color, and has a key role in avian adaptive radiations. Despite extensive work, our understanding of the underlying principles that guide the "design" of the egg as a load-bearing structure remains incomplete, especially over broad taxonomic scales. Here we define a dimensionless number C, a function of egg weight, stiffness and dimensions, to quantify how stiff an egg is with respect to its weight after removing geometry-induced rigidity. We analyze eggs of 463 bird species in 36 orders across five orders of magnitude in body mass, and find that C number is nearly invariant for most species, including tiny hummingbirds and giant elephant birds. This invariance or "design guideline" dictates that evolutionary changes in shell thickness and Young's modulus, both contributing to shell stiffness, are constrained by changes in egg weight. Our analysis illuminates unique reproductive strategies of brood parasites, kiwis, and megapodes, and quantifies the loss of safety margin for contact incubation due to artificial selection and environmental toxins. Our approach provides a mechanistic framework for a better understanding of the mechanical design of the avian egg, and may provide clues to the evolutionary origin of contact incubation of amniote eggs.
Nakatsuji, Hiroshi
2012-09-18
Just as Newtonian law governs classical physics, the Schrödinger equation (SE) and the relativistic Dirac equation (DE) rule the world of chemistry. So, if we can solve these equations accurately, we can use computation to predict chemistry precisely. However, for approximately 80 years after the discovery of these equations, chemists believed that they could not solve SE and DE for atoms and molecules that included many electrons. This Account reviews ideas developed over the past decade to further the goal of predictive quantum chemistry. Between 2000 and 2005, I discovered a general method of solving the SE and DE accurately. As a first inspiration, I formulated the structure of the exact wave function of the SE in a compact mathematical form. The explicit inclusion of the exact wave function's structure within the variational space allows for the calculation of the exact wave function as a solution of the variational method. Although this process sounds almost impossible, it is indeed possible, and I have published several formulations and applied them to solve the full configuration interaction (CI) with a very small number of variables. However, when I examined analytical solutions for atoms and molecules, the Hamiltonian integrals in their secular equations diverged. This singularity problem occurred in all atoms and molecules because it originates from the singularity of the Coulomb potential in their Hamiltonians. To overcome this problem, I first introduced the inverse SE and then the scaled SE. The latter simpler idea led to immediate and surprisingly accurate solution for the SEs of the hydrogen atom, helium atom, and hydrogen molecule. The free complement (FC) method, also called the free iterative CI (free ICI) method, was efficient for solving the SEs. In the FC method, the basis functions that span the exact wave function are produced by the Hamiltonian of the system and the zeroth-order wave function. These basis functions are called complement
Intracellular transport driven by cytoskeletal motors: General mechanisms and defects
Appert-Rolland, C.; Ebbinghaus, M.; Santen, L.
2015-09-01
Cells are the elementary units of living organisms, which are able to carry out many vital functions. These functions rely on active processes on a microscopic scale. Therefore, they are strongly out-of-equilibrium systems, which are driven by continuous energy supply. The tasks that have to be performed in order to maintain the cell alive require transportation of various ingredients, some being small, others being large. Intracellular transport processes are able to induce concentration gradients and to carry objects to specific targets. These processes cannot be carried out only by diffusion, as cells may be crowded, and quite elongated on molecular scales. Therefore active transport has to be organized. The cytoskeleton, which is composed of three types of filaments (microtubules, actin and intermediate filaments), determines the shape of the cell, and plays a role in cell motion. It also serves as a road network for a special kind of vehicles, namely the cytoskeletal motors. These molecules can attach to a cytoskeletal filament, perform directed motion, possibly carrying along some cargo, and then detach. It is a central issue to understand how intracellular transport driven by molecular motors is regulated. The interest for this type of question was enhanced when it was discovered that intracellular transport breakdown is one of the signatures of some neuronal diseases like the Alzheimer. We give a survey of the current knowledge on microtubule based intracellular transport. Our review includes on the one hand an overview of biological facts, obtained from experiments, and on the other hand a presentation of some modeling attempts based on cellular automata. We present some background knowledge on the original and variants of the TASEP (Totally Asymmetric Simple Exclusion Process), before turning to more application oriented models. After addressing microtubule based transport in general, with a focus on in vitro experiments, and on cooperative effects in the
Hummers-Pradier, Eva; Beyer, Martin; Chevallier, Patrick; Eilat-Tsanani, Sophia; Lionis, Christos; Peremans, Lieve; Petek, Davorina; Rurik, Imre; Soler, Jean Karl; Stoffers, Henri Ejh; Topsever, Pinar; Ungan, Mehmet; van Royen, Paul
2010-09-01
The 'Research Agenda for General Practice/Family Medicine and Primary Health Care in Europe' summarizes the evidence relating to the core competencies and characteristics of the Wonca Europe definition of GP/FM, and its implications for general practitioners/family doctors, researchers and policy makers. The European Journal of General Practice publishes a series of articles based on this document. The previous articles presented background, objectives, and methodology, as well results on 'primary care management' and 'community orientation' and the person-related core competencies of GP/FM. This article reflects on the general practitioner's 'specific problem solving skills'. These include decision making on diagnosis and therapy of specific diseases, accounting for the properties of primary care, but also research questions related to quality management and resource use, shared decision making, or professional education and development. Clinical research covers most specific diseases, but often lacks pragmatism and primary care relevance. Quality management is a stronghold of GP/FM research. Educational interventions can be effective when well designed for a specific setting and situation. However, their message that 'usual care' by general practitioners is insufficient may be problematic. GP and their patients need more research into diagnostic reasoning with a step-wise approach to increase predictive values in a setting characterized by uncertainty and low prevalence of specific diseases. Pragmatic comparative effectiveness studies of new and established drugs or non-pharmaceutical therapy are needed. Multi-morbidity and complexity should be addressed. Studies on therapy, communication strategies and educational interventions should consider impact on health and sustainability of effects.
A Generalized Nonlocal Calculus with Application to the Peridynamics Model for Solid Mechanics
Alali, Bacim; Liu, Kuo; Gunzburger, Max
2014-01-01
A nonlocal vector calculus was introduced in [2] that has proved useful for the analysis of the peridynamics model of nonlocal mechanics and nonlocal diffusion models. A generalization is developed that provides a more general setting for the nonlocal vector calculus that is independent of particular nonlocal models. It is shown that general nonlocal calculus operators are integral operators with specific integral kernels. General nonlocal calculus properties are developed, including nonlocal...
María Gómez Castro, Berta; De Simone, Silvia; Rossi, Riccardo; Larese De Tetto, Antonia; Carrera Ramírez, Jesús
2015-04-01
Coupled thermo-hydro-mechanical modeling is essential for CO2 storage because of (1) large amounts of CO2 will be injected, which will cause large pressure buildups and might compromise the mechanical stability of the caprock seal, (2) the most efficient technique to inject CO2 is the cold injection, which induces thermal stress changes in the reservoir and seal. These stress variations can cause mechanical failure in the caprock and can also trigger induced earthquakes. To properly assess these effects, numerical models that take into account the short and long-term thermo-hydro-mechanical coupling are an important tool. For this purpose, there is a growing need of codes that couple these processes efficiently and accurately. This work involves the development of an open-source, finite element code written in C ++ for correctly modeling the effects of thermo-hydro-mechanical coupling in the field of CO2 storage and in others fields related to these processes (geothermal energy systems, fracking, nuclear waste disposal, etc.), and capable to simulate induced seismicity. In order to be able to simulate earthquakes, a new lower dimensional interface element will be implemented in the code to represent preexisting fractures, where pressure continuity will be imposed across the fractures.
Symmetry of Hamiltonian and conserved quantity for a system of generalized classical mechanics
International Nuclear Information System (INIS)
Zhang Yi
2011-01-01
This paper focuses on a new symmetry of Hamiltonian and its conserved quantity for a system of generalized classical mechanics. The differential equations of motion of the system are established. The definition and the criterion of the symmetry of Hamiltonian of the system are given. A conserved quantity directly derived from the symmetry of Hamiltonian of the generalized classical mechanical system is given. Since a Hamilton system is a special case of the generalized classical mechanics, the results above are equally applicable to the Hamilton system. The results of the paper are the generalization of a theorem known for the existing nonsingular equivalent Lagrangian. Finally, two examples are given to illustrate the application of the results. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Czech Academy of Sciences Publication Activity Database
Náhlík, Luboš; Šestáková, L.; Hutař, Pavel; Knésl, Zdeněk
2011-01-01
Roč. 452-453, - (2011), s. 445-448 ISSN 1013-9826 R&D Projects: GA AV ČR(CZ) KJB200410803; GA ČR GA101/09/1821 Institutional research plan: CEZ:AV0Z20410507 Keywords : generalized stress intensity factor * bimaterial interface * composite materials * strain energy density factor * fracture criterion * generalized linear elastic fracture mechanics Subject RIV: JL - Materials Fatigue, Friction Mechanics
Directory of Open Access Journals (Sweden)
Waqar Azeem Khan
Full Text Available The present paper deals with the analysis of melting heat and mass transfer characteristics in the stagnation point flow of an incompressible generalized Burgers fluid over a stretching sheet in the presence of non-linear radiative heat flux. A uniform magnetic field is applied normal to the flow direction. The governing equations in dimensional form are reduced to a system of dimensionless expressions by implementation of suitable similarity transformations. The resulting dimensionless problem governing the generalized Burgers is solved analytically by using the homotopy analysis method (HAM. The effects of different flow parameters like the ratio parameter, magnetic parameter, Prandtl number, melting parameter, radiation parameter, temperature ratio parameter and Schmidt number on the velocity, heat and mass transfer characteristics are computed and presented graphically. Moreover, useful discussions in detail are carried out with the help of plotted graphs and tables. Keywords: Generalized Burgers fluid, Non-linear radiative flow, Magnetic field, Melting heat transfer
Institute of Scientific and Technical Information of China (English)
Tang Wen-Lin; Tian Gui-Hua
2011-01-01
The spheroidal wave functions are found to have extensive applications in many branches of physics and mathematics. We use the perturbation method in supersymmetric quantum mechanics to obtain the analytic ground eigenvalue and the ground eigenfunction of the angular spheroidal wave equation at low frequency in a series form. Using this approach, the numerical determinations of the ground eigenvalue and the ground eigenfunction for small complex frequencies are also obtained.
A possible generalization of the concept of symmetry in analytical mechanics
International Nuclear Information System (INIS)
Grigore, D.R.
1987-09-01
A theorem of Lee Hwa Chung suggests a possible generalization of the symmetry concept in classical mechanics. It is shown that the theory of Konstant-Souriau-Kirillov can be adapted to this more general case. The theory is illustrated with a number of exaples.(author)
Hamlin, Larry
This document contains the competency test package for three sections of a general mechanical repair course: minor automotive maintenance, small engine mechanics, and welding. Following a list of the common essential elements for trade and industrial education, competency tests for the three sections are provided. Each test includes unit name,…
Could HPS Improve Problem-Solving?
Coelho, Ricardo Lopes
2013-05-01
It is generally accepted nowadays that History and Philosophy of Science (HPS) is useful in understanding scientific concepts, theories and even some experiments. Problem-solving strategies are a significant topic, since students' careers depend on their skill to solve problems. These are the reasons for addressing the question of whether problem solving could be improved by means of HPS. Three typical problems in introductory courses of mechanics—the inclined plane, the simple pendulum and the Atwood machine—are taken as the object of the present study. The solving strategies of these problems in the eighteenth and nineteenth century constitute the historical component of the study. Its philosophical component stems from the foundations of mechanics research literature. The use of HPS leads us to see those problems in a different way. These different ways can be tested, for which experiments are proposed. The traditional solving strategies for the incline and pendulum problems are adequate for some situations but not in general. The recourse to apparent weights in the Atwood machine problem leads us to a new insight and a solving strategy for composed Atwood machines. Educational implications also concern the development of logical thinking by means of the variety of lines of thought provided by HPS.
Quantum mechanical description of the two fluid model of liquid /sup 4/He solving the Bloch equation
International Nuclear Information System (INIS)
Fung, P.C.W.; Lam, C.C.
1986-01-01
The authors apply the U-matrix theory recently developed (Lam and Fung, Phys. Rev. A, vol.27, p.1760, 1983) to study certain physical properties of liquid /sup 4/He across a range of temperatures including the lambda -point. They propose a model for the chemical potential mu which is constant above T/sub lambda / but is a function of T below T/sub lambda /. They have discovered that the super-particles 'emerge' mathematically due to the uncommutability of the Hamiltonians at different temperatures, leading to a quantum mechanical description of the two-fluid model. Using the two-particle potential function deduced from scattering data, they have calculated numerically the approximate values of the number density for a range of temperatures starting from T/sub lambda /, taking the hard-core diameter Delta , 'effective chemical potential' mu ' as parameters
Progress in Solving the Elusive Ag Transport Mechanism in TRISO Coated Particles: “What is new?”
International Nuclear Information System (INIS)
Rooyen, I.J. van; Petti, D.A.; Nabielek, H.; Neethling, J.H; Kania, M.J.
2014-01-01
The tristructural isotropic (TRISO) particle for a high temperature reactor (HTR) has been developed to an advanced state where the coating withstands internal gas pressures and retains nearly all fission products during irradiation and under postulated accidents. However, one exception is silver (Ag) that has been found to be released from high quality TRISO coated particles during irradiation and high temperature accident heating tests. Although out-of-pile laboratory tests have yet to elucidate the mechanism of transport of Ag through silicon carbide (SiC), effective diffusion coefficients have been derived to successfully reproduce measured "1"1"0"mAg- releases from irradiated HTR fuel elements, compacts and TRISO particles. It was found that Ag transport through SiC does not proceed via bulk volume diffusion. Presently grain boundary diffusion that may be irradiation enhanced either by neutron bombardment or by the presence of fission products such as palladium (Pd), are the two hypotheses that have been proposed. Recent studies of irradiated AGR-1 TRISO fuel using scanning transmission electron microscopy (STEM), transmission Kikuchi diffraction (TKD) patterns, and high resolution transmission electron microscopy (HRTEM) have been used to further the understanding of Ag transport through TRISO particles. No Ag was observed in SiC grains, but Ag was identified at triple-points and grain boundaries of the SiC layer in the TRISO particle. Cadmium (Cd) was also found in some of the very same triple junctions, but this could be related to silver behavior as "1"1"0"mAg decays to "1"1"0Cd or true Cd release as a fission product. Palladium was identified as the main constituent of micron-sized precipitates present at the SiC grain boundaries. The potential role of Pd in the transport of Ag will be discussed further. (author)
Kelly, J
2003-01-01
"Sir Alan Wilson, vice-chancellor of Leeds University, has made a career out of solving big problems. This week he landed himself one of the biggest. Appointed the government's first ever director general of higher education, he becomes responsible for advising Charles Clarke at a pivotal moment in the history of the sector" (1 page).
General-Covariant Quantum Mechanics of Dirac Particle in Curved Space-Times
International Nuclear Information System (INIS)
Tagirov, Eh.A.
1994-01-01
A general covariant analog of the standard non-relativistic Quantum Mechanics with relativistic corrections in normal geodesic frames in the general Riemannian space-time is constructed for the Dirac particle. Not only the Pauli equation with hermitian Hamiltonian and the pre-Hilbert structure of space of its solutions but also the matrix elements of hermitian operators of momentum, (curvilinear) spatial coordinates and spin of the particle are deduced as general-covariant asymptotic approximation in c -2 , c being the velocity of light, to their naturally determined general-relativistic pre images. It is shown that the Hamiltonian in the Pauli equation originated by the Dirac equation is unitary equivalent to the operator of energy, originated by the metric energy-momentum tensor of the spinor field. Commutation and other properties of the observables connected with the considered change of geometrical background of Quantum Mechanics are briefly discussed. 7 refs
Operator algebras for general one-dimensional quantum mechanical potentials with discrete spectrum
International Nuclear Information System (INIS)
Wuensche, Alfred
2002-01-01
We define general lowering and raising operators of the eigenstates for one-dimensional quantum mechanical potential problems leading to discrete energy spectra and investigate their associative algebra. The Hamilton operator is quadratic in these lowering and raising operators and corresponding representations of operators for action and angle are found. The normally ordered representation of general operators using combinatorial elements such as partitions is derived. The introduction of generalized coherent states is discussed. Linear laws for the spacing of the energy eigenvalues lead to the Heisenberg-Weyl group and general quadratic laws of level spacing to unitary irreducible representations of the Lie group SU(1, 1) that is considered in detail together with a limiting transition from this group to the Heisenberg-Weyl group. The relation of the approach to quantum deformations is discussed. In two appendices, the classical and quantum mechanical treatment of the squared tangent potential is presented as a special case of a system with quadratic level spacing
Multiple-event probability in general-relativistic quantum mechanics. II. A discrete model
International Nuclear Information System (INIS)
Mondragon, Mauricio; Perez, Alejandro; Rovelli, Carlo
2007-01-01
We introduce a simple quantum mechanical model in which time and space are discrete and periodic. These features avoid the complications related to continuous-spectrum operators and infinite-norm states. The model provides a tool for discussing the probabilistic interpretation of generally covariant quantum systems, without the confusion generated by spurious infinities. We use the model to illustrate the formalism of general-relativistic quantum mechanics, and to test the definition of multiple-event probability introduced in a companion paper [Phys. Rev. D 75, 084033 (2007)]. We consider a version of the model with unitary time evolution and a version without unitary time evolution
General structure of quantum mechanics. The objections raised by Einstein, Podolsky and Rosen
International Nuclear Information System (INIS)
Laloe, F.
1981-01-01
First, the general formulation of quantum mechanics is briefly presented, with the so called 'Copenhagen interpretation', and a few very simple examples are given. Then, the general experimental scheme imagined by Einstein, Podolsky and Rosen is discussed in detail, for two correlated spin 1/2 particules, in terms of the elements of physical reality which can be attached to the system. A macroscopic analogue is given, in order to emphasize how strange the language of quantum mechanics may become when applied to every day life phenomena, where all correlation phenomena are explained in terms of a common cause in the past. Finally, the notions of separability, locality and determinism are introduced [fr
Anti-hydrogen: The cusp between quantum mechanics and general relativity
International Nuclear Information System (INIS)
Noyes, H.P.
1992-09-01
We argue that the crossing (CPT) symmetry of relativistic quantum mechanics requires that both the coulombic and the Newtonian force between pairs of particles will reverse when one is replaced by its anti-particle. For consistency, this requires a theory in which both the equivalence principles and gauge invariance are abandoned. thus whether anti-hydrogen ''falls'' up or down will provide an experiment crusis separating general relativity and gauge invariance from this version of quantum mechanics
Emotion Oriented Programming: Computational Abstractions for AI Problem Solving
Darty , Kevin; Sabouret , Nicolas
2012-01-01
International audience; In this paper, we present a programming paradigm for AI problem solving based on computational concepts drawn from Affective Computing. It is believed that emotions participate in human adaptability and reactivity, in behaviour selection and in complex and dynamic environments. We propose to define a mechanism inspired from this observation for general AI problem solving. To this purpose, we synthesize emotions as programming abstractions that represent the perception ...
Solving Environmental Problems
DEFF Research Database (Denmark)
Ørding Olsen, Anders; Sofka, Wolfgang; Grimpe, Christoph
2017-01-01
for Research and Technological Development (FP7), our results indicate that the problem-solving potential of a search strategy increases with the diversity of existing knowledge of the partners in a consortium and with the experience of the partners involved. Moreover, we identify a substantial negative effect...... dispersed. Hence, firms need to collaborate. We shed new light on collaborative search strategies led by firms in general and for solving environmental problems in particular. Both topics are largely absent in the extant open innovation literature. Using data from the European Seventh Framework Program...
Tolhoek, H.A.; Groot, S.R. de
1949-01-01
In the general case of a quantum mechanical system with a Hamiltonian that is invariant for rotations spatial degeneracy will exist. So the initial state must be characterized except by the energy also by e.g. the magnetic quantum number. Both for emission of light and electrons plus neutrinos
International Nuclear Information System (INIS)
Makhaldiani, N.; Voskresenskaya, O.
1998-01-01
We consider selected problems of Hamiltonization and integrability of a general dynamical system described by a system of ordinary differential equations; odd and even symplectic structures; a new approach to the linearization of non-linear systems by the extended Hamiltonian and Nambu's mechanics
A generalization of Fenyes-Nelson stochastic model of quantum mechanics
International Nuclear Information System (INIS)
Davidson, M.
1979-01-01
It is shown that the stochastic model of Fenyes and Nelson can be generalized in such a way that the diffusion constant of the Markov theory becomes a free parameter. This extra freedom allows one to identify quantum mechanics with a class of Markov processes with diffusion constants varying from 0 to infinity. (Auth.)
Hamlin, Larry
This document contains a curriculum guide and lesson plans for a general mechanical repair course with three sections: minor automotive maintenance, small engine repair, and welding. The curriculum guide begins with a matrix that relates the lesson plans to essential elements of math, science, language arts, and social studies and to Texas…
Hamlin, Larry
This document is a student manual for a general mechanical repair course. Following a list of common essential elements of trade and industrial education, the manual is divided into three sections. The first section, on minor automotive maintenance, contains 13 units: automotive shop safety; engine principles; fuel system operation and repair;…
Hamlin, Larry
This curriculum guide provides materials for teachers to use in developing a 1-year course in general mechanical repair as part of the trade and industrial education curriculum. The guide contains the following: (1) essential elements common to all trade and industrial courses; (2) an instructional delivery outline (teaching sequence) for the…
International Nuclear Information System (INIS)
Levin, F.S.; Krueger, H.
1977-01-01
We propose in this article that the non-Hermitian equations typical of some many-body scattering theories be used to help solve many-body bound-state problems. The basic idea is to exploit the channel nature of many-body bound states that must exist because bound states are obvious negative-energy extensions of scattering states. Since atomic, molecular, and nuclear systems all display multichannel effects for E > 0, at least through Pauli-principle effects if not through mass-transfer reactions, this use of positive-energy methods for solving bound-state problems could have wide applicability. The development used here is based on the channel-component-state method of the channel-coupling-array theory, recently described in detail for the E > 0 case, and various aspects of the formalism are discussed. Detailed calculations using simple approximations are discussed for H 2 + , one of the simplest systems displaying channel structure. Comparison with the exact, Born-Oppenheimer results of Wind show that the non-Hermitian-equation, channel-component values of the equilibrium separation and total binding energy are accurate to within 2%, while the dissociation energy is accurate to 10%. The resulting wave function is identical to that arising from the simplest MO calculation, for which these numbers are less accurate than the preceding by at least a factor of 3. We also show that identical particle symmetry for the H 2 + case reduces the pair of coupled (two-channel) equations to a single equation with an exchange term. Similar reductions will occur for larger numbers of identical particles, thus suggesting application of the formalism to atomic structure problems. A detailed analysis of the present numerical results, their general implications, and possible applications is also given
María Gómez Castro, Berta; De Simone, Silvia; Carrera, Jesús
2016-04-01
Nowadays, there are still some unsolved relevant questions which must be faced if we want to proceed to the hydraulic fracturing in a safe way. How much will the fracture propagate? This is one of the most important questions that have to be solved in order to avoid the formation of pathways leading to aquifer targets and atmospheric release. Will the fracture failure provoke a microseismic event? Probably this is the biggest fear that people have in fracking. The aim of this work (developed as a part of the EU - FracRisk project) is to understand the hydro-mechanical coupling that controls the shear of existing fractures and their propagation during a hydraulic fracturing operation, in order to identify the key parameters that dominate these processes and answer the mentioned questions. This investigation focuses on the development of a new C++ code which simulates hydro-mechanical coupling, shear movement and propagation of a fracture. The framework employed, called Kratos, uses the Finite Element Method and the fractures are represented with an interface element which is zero thickness. This means that both sides of the element lie together in the initial configuration (it seems a 1D element in a 2D domain, and a 2D element in a 3D domain) and separate as the adjacent matrix elements deform. Since we are working in hard, fragile rocks, we can assume an elastic matrix and impose irreversible displacements in fractures when rock failure occurs. The formulation used to simulate shear and tensile failures is based on the analytical solution proposed by Okada, 1992 and it is part of an iterative process. In conclusion, the objective of this work is to employ the new code developed to analyze the main uncertainties related with the hydro-mechanical behavior of fractures derived from the hydraulic fracturing operations.
Mechanism design of reverse auction on concession period and generalized quality for PPP projects
Institute of Scientific and Technical Information of China (English)
Xianjia WANG; Shiwei WU
2017-01-01
Reverse auctions of PPP projects usually require the bid to specify several characteristics of quality and the concession period to be fulfilled.This paper sets up a summary function of generalized quality,which contributes to reducing the dimensions of information.Thus,the multidimensional reverse auction model of a PPP project can be replaced by a two-dimensional direct mechanism based on the concession period and the generalized quality.Based on the theory of the revelation principle,the feasibility conditions,equilibrium solution and generalized quality requirements of such a mechanism,considering the influence of a variable investment structure are described.Moreover,two feasible multidimensional reverse auctions for implementing such a direct mechanism:Adjusting the scoring function and establishing a special reverse auction rule are built.The analysis shows that in these types of reverse auctions,optimal allocation can be achieved,the social benefit under the incomplete information will be maximized,and the private sector with the highest integrated management level wins the bid.In such a direct mechanism,the investment and financial pressure of the public sector can be reduced.
Study on generalized Toda mechanics system with loop algebra L(Dr)
International Nuclear Information System (INIS)
Zhu Qiao; Yang Zhanying; Shi Kangjie
2005-01-01
The authors generalize the Toda mechanics system with long range interaction to the case of Loop algebra L(D r ). By using a pair of ordered positive integer (X, Y) to describe Toda chains, authors extract the equation of motion and the Hamiltonian structure of this system for (3, 2) Toda chain. It turns out that both extra coordinates and standard Toda variables are Poisson non-commutative in the case of nontrivial generalization, and for some case, extra variables appear linearly on the right hand side of the Poisson bracket. (authors)
International Nuclear Information System (INIS)
Ohta, N.
1985-01-01
After elucidating the component structure of N = 2 supersymmetric gauge theories in the harmonic superspace formalism with central charges, we reformulate our previous dipole mechanism of spontaneous breaking of N = 2 supersymmetry free from the Nambu-Goldstone-fermion difficulties in this formalism. This allows a generalization of our previous model of generating finiteness-preserving mass terms for scalar hypermultiplets; we can also obtain the gauge-fermion and scalar mass terms together with specific cubic interactions for scalar fields. The mechanism is equivalent to the so-called spurion method
Vodovotz, Yoram; Xia, Ashley; Read, Elizabeth L; Bassaganya-Riera, Josep; Hafler, David A; Sontag, Eduardo; Wang, Jin; Tsang, John S; Day, Judy D; Kleinstein, Steven H; Butte, Atul J; Altman, Matthew C; Hammond, Ross; Sealfon, Stuart C
2017-02-01
Emergent responses of the immune system result from the integration of molecular and cellular networks over time and across multiple organs. High-content and high-throughput analysis technologies, concomitantly with data-driven and mechanistic modeling, hold promise for the systematic interrogation of these complex pathways. However, connecting genetic variation and molecular mechanisms to individual phenotypes and health outcomes has proven elusive. Gaps remain in data, and disagreements persist about the value of mechanistic modeling for immunology. Here, we present the perspectives that emerged from the National Institute of Allergy and Infectious Disease (NIAID) workshop 'Complex Systems Science, Modeling and Immunity' and subsequent discussions regarding the potential synergy of high-throughput data acquisition, data-driven modeling, and mechanistic modeling to define new mechanisms of immunological disease and to accelerate the translation of these insights into therapies. Copyright © 2016 Elsevier Ltd. All rights reserved.
Boron Stress Activates the General Amino Acid Control Mechanism and Inhibits Protein Synthesis
Uluisik, Irem; Kaya, Alaattin; Fomenko, Dmitri E.; Karakaya, Huseyin C.; Carlson, Bradley A.; Gladyshev, Vadim N.; Koc, Ahmet
2011-01-01
Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS) of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance. PMID:22114689
Boron stress activates the general amino acid control mechanism and inhibits protein synthesis.
Directory of Open Access Journals (Sweden)
Irem Uluisik
Full Text Available Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance.
Farassat, Fereidoun; Myers, Michael K.
2011-01-01
This paper is the first part of a three part tutorial on multidimensional generalized functions (GFs) and their applications in aeroacoustics and fluid mechanics. The subject is highly fascinating and essential in many areas of science and, in particular, wave propagation problems. In this tutorial, we strive to present rigorously and clearly the basic concepts and the tools that are needed to use GFs in applications effectively and with ease. We give many examples to help the readers in understanding the mathematical ideas presented here. The first part of the tutorial is on the basic concepts of GFs. Here we define GFs, their properties and some common operations on them. We define the important concept of generalized differentiation and then give some interesting elementary and advanced examples on Green's functions and wave propagation problems. Here, the analytic power of GFs in applications is demonstrated with ease and elegance. Part 2 of this tutorial is on the diverse applications of generalized derivatives (GDs). Part 3 is on generalized Fourier transformations and some more advanced topics. One goal of writing this tutorial is to convince readers that, because of their powerful operational properties, GFs are absolutely essential and useful in engineering and physics, particularly in aeroacoustics and fluid mechanics.
Wang, Fei; Gong, Haoran; Chen, Xi; Chen, C. Q.
2016-09-01
Origami structures enrich the field of mechanical metamaterials with the ability to convert morphologically and systematically between two-dimensional (2D) thin sheets and three-dimensional (3D) spatial structures. In this study, an in-plane design method is proposed to approximate curved surfaces of interest with generalized Miura-ori units. Using this method, two combination types of crease lines are unified in one reprogrammable procedure, generating multiple types of cylindrical structures. Structural completeness conditions of the finite-thickness counterparts to the two types are also proposed. As an example of the design method, the kinematics and elastic properties of an origami-based circular cylindrical shell are analysed. The concept of Poisson’s ratio is extended to the cylindrical structures, demonstrating their auxetic property. An analytical model of rigid plates linked by elastic hinges, consistent with numerical simulations, is employed to describe the mechanical response of the structures. Under particular load patterns, the circular shells display novel mechanical behaviour such as snap-through and limiting folding positions. By analysing the geometry and mechanics of the origami structures, we extend the design space of mechanical metamaterials and provide a basis for their practical applications in science and engineering.
Solving rational expectations models using Excel
DEFF Research Database (Denmark)
Strulik, Holger
2004-01-01
Problems of discrete time optimal control can be solved using backward iteration and Microsoft Excel. The author explains the method in general and shows how the basic models of neoclassical growth and real business cycles are solved......Problems of discrete time optimal control can be solved using backward iteration and Microsoft Excel. The author explains the method in general and shows how the basic models of neoclassical growth and real business cycles are solved...
Luo, X. M.; Zhang, B.; Zhang, G. P.
2014-09-01
Thermal fatigue failure of metallization interconnect lines subjected to alternating currents (AC) is becoming a severe threat to the long-term reliability of micro/nanodevices with increasing electrical current density/power. Here, thermal fatigue failure behaviors and damage mechanisms of nanocrystalline Au interconnect lines on the silicon glass substrate have been investigated by applying general alternating currents (the pure alternating current coupled with a direct current (DC) component) with different frequencies ranging from 0.05 Hz to 5 kHz. We observed both thermal fatigue damages caused by Joule heating-induced cyclic strain/stress and electromigration (EM) damages caused by the DC component. Besides, the damage formation showed a strong electrically-thermally-mechanically coupled effect and frequency dependence. At lower frequencies, thermal fatigue damages were dominant and the main damage forms were grain coarsening with grain boundary (GB) cracking/voiding and grain thinning. At higher frequencies, EM damages took over and the main damage forms were GB cracking/voiding of smaller grains and hillocks. Furthermore, the healing effect of the reversing current was considered to elucidate damage mechanisms of the nanocrystalline Au lines generated by the general AC. Lastly, a modified model was proposed to predict the lifetime of the nanocrystalline metal interconnect lines, i.e., that was a competing drift velocity-based approach based on the threshold time required for reverse diffusion/healing to occur.
Behavioral tagging is a general mechanism of long-term memory formation.
Ballarini, Fabricio; Moncada, Diego; Martinez, Maria Cecilia; Alen, Nadia; Viola, Haydée
2009-08-25
In daily life, memories are intertwined events. Little is known about the mechanisms involved in their interactions. Using two hippocampus-dependent (spatial object recognition and contextual fear conditioning) and one hippocampus-independent (conditioned taste aversion) learning tasks, we show that in rats subjected to weak training protocols that induce solely short term memory (STM), long term memory (LTM) is promoted and formed only if training sessions took place in contingence with a novel, but not familiar, experience occurring during a critical time window around training. This process requires newly synthesized proteins induced by novelty and reveals a general mechanism of LTM formation that begins with the setting of a "learning tag" established by a weak training. These findings represent the first comprehensive set of evidences indicating the existence of a behavioral tagging process that in analogy to the synaptic tagging and capture process, need the creation of a transient, protein synthesis-independent, and input specific tag.
Michelmann, Sebastian; Bowman, Howard; Hanslmayr, Simon
2016-01-01
Reinstatement of dynamic memories requires the replay of neural patterns that unfold over time in a similar manner as during perception. However, little is known about the mechanisms that guide such a temporally structured replay in humans, because previous studies used either unsuitable methods or paradigms to address this question. Here, we overcome these limitations by developing a new analysis method to detect the replay of temporal patterns in a paradigm that requires participants to mentally replay short sound or video clips. We show that memory reinstatement is accompanied by a decrease of low-frequency (8 Hz) power, which carries a temporal phase signature of the replayed stimulus. These replay effects were evident in the visual as well as in the auditory domain and were localized to sensory-specific regions. These results suggest low-frequency phase to be a domain-general mechanism that orchestrates dynamic memory replay in humans. PMID:27494601
Directory of Open Access Journals (Sweden)
Sebastian Michelmann
2016-08-01
Full Text Available Reinstatement of dynamic memories requires the replay of neural patterns that unfold over time in a similar manner as during perception. However, little is known about the mechanisms that guide such a temporally structured replay in humans, because previous studies used either unsuitable methods or paradigms to address this question. Here, we overcome these limitations by developing a new analysis method to detect the replay of temporal patterns in a paradigm that requires participants to mentally replay short sound or video clips. We show that memory reinstatement is accompanied by a decrease of low-frequency (8 Hz power, which carries a temporal phase signature of the replayed stimulus. These replay effects were evident in the visual as well as in the auditory domain and were localized to sensory-specific regions. These results suggest low-frequency phase to be a domain-general mechanism that orchestrates dynamic memory replay in humans.
A statistical mechanical approach for the computation of the climatic response to general forcings
Directory of Open Access Journals (Sweden)
V. Lucarini
2011-01-01
Full Text Available The climate belongs to the class of non-equilibrium forced and dissipative systems, for which most results of quasi-equilibrium statistical mechanics, including the fluctuation-dissipation theorem, do not apply. In this paper we show for the first time how the Ruelle linear response theory, developed for studying rigorously the impact of perturbations on general observables of non-equilibrium statistical mechanical systems, can be applied with great success to analyze the climatic response to general forcings. The crucial value of the Ruelle theory lies in the fact that it allows to compute the response of the system in terms of expectation values of explicit and computable functions of the phase space averaged over the invariant measure of the unperturbed state. We choose as test bed a classical version of the Lorenz 96 model, which, in spite of its simplicity, has a well-recognized prototypical value as it is a spatially extended one-dimensional model and presents the basic ingredients, such as dissipation, advection and the presence of an external forcing, of the actual atmosphere. We recapitulate the main aspects of the general response theory and propose some new general results. We then analyze the frequency dependence of the response of both local and global observables to perturbations having localized as well as global spatial patterns. We derive analytically several properties of the corresponding susceptibilities, such as asymptotic behavior, validity of Kramers-Kronig relations, and sum rules, whose main ingredient is the causality principle. We show that all the coefficients of the leading asymptotic expansions as well as the integral constraints can be written as linear function of parameters that describe the unperturbed properties of the system, such as its average energy. Some newly obtained empirical closure equations for such parameters allow to define such properties as an explicit function of the unperturbed forcing
Improved probabilistic inference as a general learning mechanism with action video games.
Green, C Shawn; Pouget, Alexandre; Bavelier, Daphne
2010-09-14
Action video game play benefits performance in an array of sensory, perceptual, and attentional tasks that go well beyond the specifics of game play [1-9]. That a training regimen may induce improvements in so many different skills is notable because the majority of studies on training-induced learning report improvements on the trained task but limited transfer to other, even closely related, tasks ([10], but see also [11-13]). Here we ask whether improved probabilistic inference may explain such broad transfer. By using a visual perceptual decision making task [14, 15], the present study shows for the first time that action video game experience does indeed improve probabilistic inference. A neural model of this task [16] establishes how changing a single parameter, namely the strength of the connections between the neural layer providing the momentary evidence and the layer integrating the evidence over time, captures improvements in action-gamers behavior. These results were established in a visual, but also in a novel auditory, task, indicating generalization across modalities. Thus, improved probabilistic inference provides a general mechanism for why action video game playing enhances performance in a wide variety of tasks. In addition, this mechanism may serve as a signature of training regimens that are likely to produce transfer of learning. Copyright © 2010 Elsevier Ltd. All rights reserved.
Exact Descriptions of General Relativity Derived from Newtonian Mechanics within Curved Geometries
Savickas, David
2015-04-01
General relativity and Newtonian mechanics are shown to be exactly related when Newton's second law is written in a curved geometry by using the physical components of a vector as is defined in tensor calculus. By replacing length within the momentum's velocity by the vector metric in a curved geometry the second law can then be shown to be exactly identical to the geodesic equation of motion occurring in general relativity. When time's vector direction is constant, as similarly occurs in Newtonian mechanics, this equation can be reduced to a curved three-dimensional equation of motion that yields the the Schwarzschild equations of motion for an isolated particle. They can be used to describe gravitational behavior for any array of masses for which the Newtonian gravitational potential is known, and is shown to describe a mass particle's behavior in the gravitational field of a thin mass-rod. This use of Newton's laws allows relativistic behavior to be described in a physically comprehensible manner. D. Savickas, Int. J. Mod. Phys. D 23 1430018, (2014).
DEFF Research Database (Denmark)
Foss, Kirsten; Foss, Nicolai Juul
2006-01-01
as a general approach to problem solving. We apply these Simonian ideas to organisational issues, specifically new organisational forms. Specifically, Simonian ideas allow us to develop a morphology of new organisational forms and to point to some design problems that characterise these forms.......Two of Herbert Simon's best-known papers are 'The Architecture of Complexity' and 'The Structure of Ill-Structured Problems.' We discuss the neglected links between these two papers, highlighting the role of decomposition in the context of problems on which constraints have been imposed...
2013-10-01
We are continuing to collect data through interviews and document searches, following a process of theoretical sampling (Clarke, 2005; Locke, 2001...problem solving. These interviews were recorded and transcribed. We collected additional data from two sources, a snowballing Google search and the
The Born-Infeld vortices induced from a generalized Higgs mechanism.
Han, Xiaosen
2016-04-01
We construct self-dual Born-Infeld vortices induced from a generalized Higgs mechanism. Two specific models of the theory are of focused interest where the Higgs potential is either of a | ϕ | 4 - or | ϕ | 6 -type. For the | ϕ | 4 -model, we obtain a sharp existence and uniqueness theorem for doubly periodic and planar vortices. For doubly periodic solutions, a necessary and sufficient condition for the existence is explicitly derived in terms of the vortex number, the Born-Infeld parameter, and the size of the periodic lattice domain. For the | ϕ | 6 -model, we show that both topological and non-topological vortices are present. This new phenomenon distinguishes the model from the classical Born-Infeld-Higgs theory studied earlier in the literature. A series of results regarding doubly periodic, topological, and non-topological vortices in the | ϕ | 6 -model are also established.
Gabriel, M G; Curtiss, Joshua; Hofmann, Stefan G; Khalsa, Sat Bir S
2018-04-26
The aim of this study was to examine the efficacy of Kundalini Yoga in reducing symptoms of generalized anxiety disorder (GAD) compared to a common treatment-as-usual condition using cognitive techniques. A secondary objective was to explore potential treatment mechanisms. Females aged 24 to 75 years with GAD ( n = 49) received either an 8-week Kundalini Yoga intervention ( n = 34) or an 8-week treatment-as-usual condition ( n = 15). The yoga condition resulted in lower levels of anxiety relative to the treatment-as-usual condition. Furthermore, changes in somatic symptoms mediated treatment outcome for Kundalini Yoga. Kundalini Yoga may show promise as a treatment for GAD, and this treatment might convey its effect on symptom severity by reducing somatic symptoms.
A general procedure for thermomechanical calibration of nano/micro-mechanical resonators
International Nuclear Information System (INIS)
Hauer, B.D.; Doolin, C.; Beach, K.S.D.; Davis, J.P.
2013-01-01
We describe a general procedure to calibrate the detection of a nano/micro-mechanical resonator’s displacement as it undergoes thermal Brownian motion. A brief introduction to the equations of motion for such a resonator is presented, followed by a detailed derivation of the corresponding power spectral density (PSD) function, which is identical in all situations aside from a system-dependent effective mass value. The effective masses for a number of different resonator geometries are determined using both finite element method (FEM) modeling and analytical calculations. -- Highlights: •Model micro- and nanomechanical resonators displaced by their own thermal motion. •Review the theoretical framework for describing thermomechanical systems. •Present a recipe for measurement calibration on devices of arbitrary shape. •Point out and correct inconsistencies in the existing literature. •Provide an authoritative guide and reference for practitioners in this area
A general procedure for thermomechanical calibration of nano/micro-mechanical resonators
Energy Technology Data Exchange (ETDEWEB)
Hauer, B.D., E-mail: bhauer@ualberta.ca; Doolin, C.; Beach, K.S.D., E-mail: kbeach@ualberta.ca; Davis, J.P., E-mail: jdavis@ualberta.ca
2013-12-15
We describe a general procedure to calibrate the detection of a nano/micro-mechanical resonator’s displacement as it undergoes thermal Brownian motion. A brief introduction to the equations of motion for such a resonator is presented, followed by a detailed derivation of the corresponding power spectral density (PSD) function, which is identical in all situations aside from a system-dependent effective mass value. The effective masses for a number of different resonator geometries are determined using both finite element method (FEM) modeling and analytical calculations. -- Highlights: •Model micro- and nanomechanical resonators displaced by their own thermal motion. •Review the theoretical framework for describing thermomechanical systems. •Present a recipe for measurement calibration on devices of arbitrary shape. •Point out and correct inconsistencies in the existing literature. •Provide an authoritative guide and reference for practitioners in this area.
International Nuclear Information System (INIS)
Sukhanov, A.D.
2004-01-01
Generalized correlations of the Schroedinger indefinitenesses are shown to have the meaning of the fundamental restrictions as to characteristics of space of states in any probability-like theory. Quantum mechanics, as well as, theory of the brownian movement at arbitrary space of time fall in the category of the mentioned theories. One compared correlations of coordinates-pulse indefinitenesses within the mentioned theory with the similar correlation of indefinitenesses for microparticle under the Gaussian wave packet state. One determined that in case of profound distinction in mathematical tools of two theories one observes their conceptual resemblance. It manifests itself under the alternative conditions - short times in one theory correspond to long ones in another theory and vice versa, while in any of the mentioned theories uncontrollable effect of either quantum or thermal type is of crucial importance [ru
Timilsina, Govinda R; Shrestha, Ram M
2006-09-01
The Clean Development Mechanism (CDM) under the Kyoto Protocol to the United Nations Framework Convention on Climate Change is considered a key instrument to encourage developing countries' participation in the mitigation of global climate change. Reduction of greenhouse gas (GHG) emissions through the energy supply and demand side activities are the main options to be implemented under the CDM. This paper analyses the general equilibrium effects of a supply side GHG mitigation option-the substitution of thermal power with hydropower--in Thailand under the CDM. A static multi-sector general equilibrium model has been developed for the purpose of this study. The key finding of the study is that the substitution of electricity generation from thermal power plants with that from hydropower plants would increase economic welfare in Thailand. The supply side option would, however, adversely affect the gross domestic product (GDP) and the trade balance. The percentage changes in economic welfare, GDP and trade balance increase with the level of substitution and the price of certified emission reduction (CER) units.
Appplication of a general fluid mechanics program to NTP system modeling
International Nuclear Information System (INIS)
Lee, S.K.
1993-01-01
An effort is currently underway at NASA and the Department of Energy (DOE) to develop an accurate model for predicting nuclear thermal propulsion (NTP) system performance. The objective of the effort is to develop several levels of computer programs which vary in detail and complexity according to user's needs. The current focus is on the Level 1 steady-state, parametric system model. This system model will combine a general fluid mechanics program, SAFSIM, with the ability to analyze turbines, pumps, nozzles, and reactor physics. SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program that simulates integrated performance of systems involving fluid mechanics, heat transfer, and reactor dynamics. SAFSIM has the versatility to allow simulation of almost any system, including a nuclear reactor system. The focus of this paper is the validation of SAFSIM's capabilities as a base computational engine for a nuclear thermal propulsion system model. Validation is being accomplished by modeling of a nuclear engine test using SAFSIM and comparing the results to known experimental data
A generalized allosteric mechanism for cis-regulated cyclic nucleotide binding domains.
Directory of Open Access Journals (Sweden)
Alexandr P Kornev
2008-04-01
Full Text Available Cyclic nucleotides (cAMP and cGMP regulate multiple intracellular processes and are thus of a great general interest for molecular and structural biologists. To study the allosteric mechanism of different cyclic nucleotide binding (CNB domains, we compared cAMP-bound and cAMP-free structures (PKA, Epac, and two ionic channels using a new bioinformatics method: local spatial pattern alignment. Our analysis highlights four major conserved structural motifs: 1 the phosphate binding cassette (PBC, which binds the cAMP ribose-phosphate, 2 the "hinge," a flexible helix, which contacts the PBC, 3 the beta(2,3 loop, which provides precise positioning of an invariant arginine from the PBC, and 4 a conserved structural element consisting of an N-terminal helix, an eight residue loop and the A-helix (N3A-motif. The PBC and the hinge were included in the previously reported allosteric model, whereas the definition of the beta(2,3 loop and the N3A-motif as conserved elements is novel. The N3A-motif is found in all cis-regulated CNB domains, and we present a model for an allosteric mechanism in these domains. Catabolite gene activator protein (CAP represents a trans-regulated CNB domain family: it does not contain the N3A-motif, and its long range allosteric interactions are substantially different from the cis-regulated CNB domains.
Montuoro, Paul; Mainhard, Tim
2017-01-01
Background: Considerable research has investigated the deleterious effects of teachers responding aggressively to students who misbehave, but the mechanism underlying this dysfunctional behaviour remains unknown. Aims: This study investigated whether the mechanism underlying teacher aggression follows I[superscript 3] theory or General Aggression…
International Nuclear Information System (INIS)
Heusler, Stefan
2006-01-01
The main focus of the second, enlarged edition of the book Mathematica for Theoretical Physics is on computational examples using the computer program Mathematica in various areas in physics. It is a notebook rather than a textbook. Indeed, the book is just a printout of the Mathematica notebooks included on the CD. The second edition is divided into two volumes, the first covering classical mechanics and nonlinear dynamics, the second dealing with examples in electrodynamics, quantum mechanics, general relativity and fractal geometry. The second volume is not suited for newcomers because basic and simple physical ideas which lead to complex formulas are not explained in detail. Instead, the computer technology makes it possible to write down and manipulate formulas of practically any length. For researchers with experience in computing, the book contains a lot of interesting and non-trivial examples. Most of the examples discussed are standard textbook problems, but the power of Mathematica opens the path to more sophisticated solutions. For example, the exact solution for the perihelion shift of Mercury within general relativity is worked out in detail using elliptic functions. The virial equation of state for molecules' interaction with Lennard-Jones-like potentials is discussed, including both classical and quantum corrections to the second virial coefficient. Interestingly, closed solutions become available using sophisticated computing methods within Mathematica. In my opinion, the textbook should not show formulas in detail which cover three or more pages-these technical data should just be contained on the CD. Instead, the textbook should focus on more detailed explanation of the physical concepts behind the technicalities. The discussion of the virial equation would benefit much from replacing 15 pages of Mathematica output with 15 pages of further explanation and motivation. In this combination, the power of computing merged with physical intuition would
International Nuclear Information System (INIS)
Diez, F.; Horro, R.
2000-01-01
This paper presents a brief description of the CAREM reactor pressure vessel and its main internal mechanical components and summarizes the functional requirements and approaches applied for their design, together with a review of the normative applicable in each case
International Nuclear Information System (INIS)
Tarasov, V.E.
1994-07-01
Sedov variational principle, which is the generalization of the least actional principle for the dissipative processes is used to generalize the canonical quantization and von Neumann equation for dissipative systems (particles and strings). (author). 66 refs, 1 fig
On a testable unification of electromagnetics, general relativity, and quantum mechanics
International Nuclear Information System (INIS)
Bearden, T.E.; Rosenthal, W.
1991-01-01
Unrecognized for what it was, in 1903-1904 E.T. Whittaker (W) published a fundamental, engineerable theory of electogravitation (EG) in two profound papers. The first (W-1903) demonstrated a hidden bidirectional EM wave structure in the scalar potential of vacuum, and showed how to produce a standing scalar EM potential wave -- the same wave discovered experimentally four years earlier by Nikola Tesla. W-1903 is a hidden variable theory that shows how to determinsitically curve the local and/or distant spacetime using EM. W-1904 shows that all force field EM can be replaced by interferometry of two scalar potentials, anticipating the Aharonov-Bohm effect by 55 years and extending it to the engineerable macroscopic world. W-1903 shows how to turn EM into G-potential, curve local and/or distant spacetime, and directly engineer the virtual particle flux of vacuum. W-1904 shows how to turn G-potential and curvature of spacetime back into force-field EM, even at a distance. The papers implement Sahkarov's 1968 statement that gravitation is not a fundamental field of nature, gut a conglomerate of other fields. Separately applied to electromagnetic (EM), quantum mechanics (QM), and general relativity (GR), an extended superset of each results. The three supersets are Whittaker-unified, so that a testable, engineerable, unified field theory is generated. EM, QM, and GR each contained a fundamental error that blocked unification, and these three errors are explain. The Schroedinger potential can also be structured and altered, indicating the direct engineering of physical quantum change. Recently Ignatovich has pointed out this hidden bidirectional EM wave structure in the Schroedinger potential, without referencing Whittaker's 1903 discovery of the basic effect
Directory of Open Access Journals (Sweden)
Mohammed Essaid Riffi
2017-11-01
Full Text Available The bat algorithm is one of the recent nature-inspired algorithms, which has been emerged as a powerful search method for solving continuous as well as discrete problems. The quadratic assignment problem is a well-known NP-hard problem in combinatorial optimization. The goal of this problem is to assign n facilities to n locations in such a way as to minimize the assignment cost. For that purpose, this paper introduces a novel discrete variant of bat algorithm to deal with this combinatorial optimization problem. The proposed algorithm was evaluated on a set of benchmark instances from the QAPLIB library and the performance was compared to other algorithms. The empirical results of exhaustive experiments were promising and illustrated the efficacy of the suggested approach.
DEFF Research Database (Denmark)
Foss, Kirsten; Foss, Nicolai Juul
as a general approach to problem solving. We apply these Simonian ideas to organizational issues, specifically new organizational forms. Specifically, Simonian ideas allow us to develop a morphology of new organizational forms and to point to some design problems that characterize these forms.Keywords: Herbert...... Simon, problem-solving, new organizational forms. JEL Code: D23, D83......Two of Herbert Simon's best-known papers are "The Architecture of Complexity" and "The Structure of Ill-Structured Problems." We discuss the neglected links between these two papers, highlighting the role of decomposition in the context of problems on which constraints have been imposed...
Inference rule and problem solving
Energy Technology Data Exchange (ETDEWEB)
Goto, S
1982-04-01
Intelligent information processing signifies an opportunity of having man's intellectual activity executed on the computer, in which inference, in place of ordinary calculation, is used as the basic operational mechanism for such an information processing. Many inference rules are derived from syllogisms in formal logic. The problem of programming this inference function is referred to as a problem solving. Although logically inference and problem-solving are in close relation, the calculation ability of current computers is on a low level for inferring. For clarifying the relation between inference and computers, nonmonotonic logic has been considered. The paper deals with the above topics. 16 references.
Math, Souvik; Horn, Roger; Jayaram, Vikram; Biswas, Sanjay Kumar
2007-04-15
Currently data obtained from surface force apparatus experiments are convoluted with the mechanical response of glue of unknown thickness, used to bond mica sheets to the substrates. This paper describes a formulation to precisely deconvolute out the forces between the mica sheets by determining the thickness of glue, knowing the mechanical properties of the glue. The formulation consists of a general solution based on the noniterative Hankel transform of the Laplace equation. The generality is achieved by treating all the layers except the one in contact as an effective lumped system consisting of a set of springs in series, where each spring represents a layer. The solution is validated by nanoindentation of trilayer systems consisting of layers with widely diverse mechanical properties, some differing from each other by three orders of magnitude. SFA experiments are done with carefully metered slabs of glue. The proposed method is validated by comparing the actual glue thicknesses with those determined using the present analysis.
Energy Technology Data Exchange (ETDEWEB)
Kinugawa, Tohru, E-mail: kinugawa@phoenix.kobe-u.ac.jp [Institute for Promotion of Higher Education, Kobe University, Kobe 657-8501 (Japan)
2014-02-15
This paper presents a simple but nontrivial generalization of Abel's mechanical problem, based on the extended isochronicity condition and the superposition principle. There are two primary aims. The first one is to reveal the linear relation between the transit-time T and the travel-length X hidden behind the isochronicity problem that is usually discussed in terms of the nonlinear equation of motion (d{sup 2}X)/(dt{sup 2}) +(dU)/(dX) =0 with U(X) being an unknown potential. Second, the isochronicity condition is extended for the possible Abel-transform approach to designing the isochronous trajectories of charged particles in spectrometers and/or accelerators for time-resolving experiments. Our approach is based on the integral formula for the oscillatory motion by Landau and Lifshitz [Mechanics (Pergamon, Oxford, 1976), pp. 27–29]. The same formula is used to treat the non-periodic motion that is driven by U(X). Specifically, this unknown potential is determined by the (linear) Abel transform X(U) ∝ A[T(E)], where X(U) is the inverse function of U(X), A=(1/√(π))∫{sub 0}{sup E}dU/√(E−U) is the so-called Abel operator, and T(E) is the prescribed transit-time for a particle with energy E to spend in the region of interest. Based on this Abel-transform approach, we have introduced the extended isochronicity condition: typically, τ = T{sub A}(E) + T{sub N}(E) where τ is a constant period, T{sub A}(E) is the transit-time in the Abel type [A-type] region spanning X > 0 and T{sub N}(E) is that in the Non-Abel type [N-type] region covering X < 0. As for the A-type region in X > 0, the unknown inverse function X{sub A}(U) is determined from T{sub A}(E) via the Abel-transform relation X{sub A}(U) ∝ A[T{sub A}(E)]. In contrast, the N-type region in X < 0 does not ensure this linear relation: the region is covered with a predetermined potential U{sub N}(X) of some arbitrary choice, not necessarily obeying the Abel-transform relation. In
Togelius, Julian; Yannakakis, Georgios N.; 2016 IEEE Conference on Computational Intelligence and Games (CIG)
2016-01-01
Arguably the grand goal of artificial intelligence research is to produce machines with general intelligence: the capacity to solve multiple problems, not just one. Artificial intelligence (AI) has investigated the general intelligence capacity of machines within the domain of games more than any other domain given the ideal properties of games for that purpose: controlled yet interesting and computationally hard problems. This line of research, however, has so far focuse...
Li, Zhenhai; Nie, Chenwei; Yang, Guijun; Xu, Xingang; Jin, Xiuliang; Gu, Xiaohe
2014-10-01
Leaf area index (LAI) and LCC, as the two most important crop growth variables, are major considerations in management decisions, agricultural planning and policy making. Estimation of canopy biophysical variables from remote sensing data was investigated using a radiative transfer model. However, the ill-posed problem is unavoidable for the unique solution of the inverse problem and the uncertainty of measurements and model assumptions. This study focused on the use of agronomy mechanism knowledge to restrict and remove the ill-posed inversion results. For this purpose, the inversion results obtained using the PROSAIL model alone (NAMK) and linked with agronomic mechanism knowledge (AMK) were compared. The results showed that AMK did not significantly improve the accuracy of LAI inversion. LAI was estimated with high accuracy, and there was no significant improvement after considering AMK. The validation results of the determination coefficient (R2) and the corresponding root mean square error (RMSE) between measured LAI and estimated LAI were 0.635 and 1.022 for NAMK, and 0.637 and 0.999 for AMK, respectively. LCC estimation was significantly improved with agronomy mechanism knowledge; the R2 and RMSE values were 0.377 and 14.495 μg cm-2 for NAMK, and 0.503 and 10.661 μg cm-2 for AMK, respectively. Results of the comparison demonstrated the need for agronomy mechanism knowledge in radiative transfer model inversion.
Generalized Airy functions for use in one-dimensional quantum mechanical problems
Eaves, J. O.
1972-01-01
The solution of the one dimensional, time independent, Schroedinger equation in which the energy minus the potential varies as the nth power of the distance is obtained from proper linear combinations of Bessel functions. The linear combinations called generalized Airy functions, reduce to the usual Airy functions Ai(x) and Bi(x) when n equals 1 and have the same type of simple asymptotic behavior. Expressions for the generalized Airy functions which can be evaluated by the method of generalized Gaussian quadrature are obtained.
2012-05-01
This survey of the feasibility of introducing carbon capture and storage (CCS) into light vehicles : started by reviewing the level of international support for CCS in general. While there have been : encouraging signs that CCS is gaining acceptance ...
Severgnini, Paolo; Selmo, Gabriele; Lanza, Christian; Chiesa, Alessandro; Frigerio, Alice; Bacuzzi, Alessandro; Dionigi, Gianlorenzo; Novario, Raffaele; Gregoretti, Cesare; de Abreu, Marcelo Gama; Schultz, Marcus J.; Jaber, Samir; Futier, Emmanuel; Chiaranda, Maurizio; Pelosi, Paolo
2013-01-01
The impact of intraoperative ventilation on postoperative pulmonary complications is not defined. The authors aimed at determining the effectiveness of protective mechanical ventilation during open abdominal surgery on a modified Clinical Pulmonary Infection Score as primary outcome and
Behavioral pattern separation and its link to the neural mechanisms of fear generalization.
Lange, Iris; Goossens, Liesbet; Michielse, Stijn; Bakker, Jindra; Lissek, Shmuel; Papalini, Silvia; Verhagen, Simone; Leibold, Nicole; Marcelis, Machteld; Wichers, Marieke; Lieverse, Ritsaert; van Os, Jim; van Amelsvoort, Therese; Schruers, Koen
2017-11-01
Fear generalization is a prominent feature of anxiety disorders and post-traumatic stress disorder (PTSD). It is defined as enhanced fear responding to a stimulus that bears similarities, but is not identical to a threatening stimulus. Pattern separation, a hippocampal-dependent process, is critical for stimulus discrimination; it transforms similar experiences or events into non-overlapping representations. This study is the first in humans to investigate the extent to which fear generalization relies on behavioral pattern separation abilities. Participants (N = 46) completed a behavioral task taxing pattern separation, and a neuroimaging fear conditioning and generalization paradigm. Results show an association between lower behavioral pattern separation performance and increased generalization in shock expectancy scores, but not in fear ratings. Furthermore, lower behavioral pattern separation was associated with diminished recruitment of the subcallosal cortex during presentation of generalization stimuli. This region showed functional connectivity with the orbitofrontal cortex and ventromedial prefrontal cortex. Together, the data provide novel experimental evidence that pattern separation is related to generalization of threat expectancies, and reduced fear inhibition processes in frontal regions. Deficient pattern separation may be critical in overgeneralization and therefore may contribute to the pathophysiology of anxiety disorders and PTSD. © The Author (2017). Published by Oxford University Press.
Lisa, María-Natalia; Palacios, Antonela R; Aitha, Mahesh; González, Mariano M; Moreno, Diego M; Crowder, Michael W; Bonomo, Robert A; Spencer, James; Tierney, David L; Llarrull, Leticia I; Vila, Alejandro J
2017-09-14
Carbapenem-resistant Enterobacteriaceae threaten human health, since carbapenems are last resort drugs for infections by such organisms. Metallo-β-lactamases (MβLs) are the main mechanism of resistance against carbapenems. Clinically approved inhibitors of MBLs are currently unavailable as design has been limited by the incomplete knowledge of their mechanism. Here, we report a biochemical and biophysical study of carbapenem hydrolysis by the B1 enzymes NDM-1 and BcII in the bi-Zn(II) form, the mono-Zn(II) B2 Sfh-I and the mono-Zn(II) B3 GOB-18. These MβLs hydrolyse carbapenems via a similar mechanism, with accumulation of the same anionic intermediates. We characterize the Michaelis complex formed by mono-Zn(II) enzymes, and we identify all intermediate species, enabling us to propose a chemical mechanism for mono and binuclear MβLs. This common mechanism open avenues for rationally designed inhibitors of all MβLs, notwithstanding the profound differences between these enzymes' active site structure, β-lactam specificity and metal content.Carbapenem-resistant bacteria pose a major health threat by expressing metallo-β-lactamases (MβLs), enzymes able to hydrolyse these life-saving drugs. Here the authors use biophysical and computational methods and show that different MβLs share the same reaction mechanism, suggesting new strategies for drug design.
Coletta, Vincent P.; Phillips, Jeffrey A.; Savinainen, Antti; Steinert, Jeffrey J.
2008-09-01
In a recent article, Ates and Cataloglu (2007 Eur. J. Phys. 28 1161-71), in analysing results for a course in introductory mechanics for prospective science teachers, found no statistically significant correlation between students' pre-instruction scores on the Lawson classroom test of scientific reasoning ability (CTSR) and post-instruction scores on the force concept inventory (FCI). As a possible explanation, the authors suggest that the FCI does not probe for skills required to determine reasoning abilities. Our previously published research directly contradicts the authors' finding. We summarize our research and present a likely explanation for their observation of no correlation.
Yin, Honglian; Sun, Aihua; Liu, Quanru; Chen, Zhiyi
2018-03-01
It is the key of motivating sub-contractors working hard and mutual cooperation, ensuring implementation overall goal of the project that to design rational incentive mechanism for general contractor. Based on the principal-agency theory, the subcontractor efforts is divided into two parts, one for individual efforts, another helping other subcontractors, team Cooperation incentive models of multiple subcontractors are set up, incentive schemes and intensities are also given. The results show that the general contractor may provide individual and team motivation incentives when subcontractors working independently, not affecting each other in time and space; otherwise, the general contractor may only provide individual incentive to entice teams collaboration between subcontractors and helping each other. The conclusions can provide a reference for the subcontract design of general and sub-contractor dynamic alliances.
Chapter 1. General information about uranium. 1.5. Mechanical properties
International Nuclear Information System (INIS)
Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.
2012-01-01
Full text: The mechanical properties of uranium depend on its purity, and which mechanical and thermal regimes are used for reprocessing. The average elasticity module value for cast uranium is 20.5•10"-"2 mega newton/m"2 (20.9•10"-"3 kilogram-force/mm"2), strength limit during tension at room temperature is 372–470 mega newton/m"2 (38–48 kilogram-force/mm"2), strength is increased after hardening from β - and γ - phases; and average rigidity by Brinell 19.6–21.6•10"2 mega newton/m"2 (200–220 kilogram-force/mm"2). Exposure by neutron flux (which occurs in nuclear reactors) changes the physical and mechanical properties of uranium: creeping develops and brittleness increases, goods deformation is observed, which forces the operator to use uranium in nuclear reactors as different uranium alloys.
Photoreactors for Solving Problems of Environmental Pollution
Tchaikovskaya, O. N.; Sokolova, I. V.
2015-04-01
Designs and physical aspects of photoreactors, their capabilities for a study of kinetics and mechanisms of processes proceeding under illumination with light, as well as application of photoreactors for solving various applied problem are discussed.
van Geert, P
Dynamic systems theory conceives of development as a self-organizational process. Both complexity and order emerge as a product of elementary principles of interaction between components involved in the developmental process. This article presents a dynamic systems model based on a general dual
Selective Short-Term Memory Deficits Arise from Impaired Domain-General Semantic Control Mechanisms
Hoffman, Paul; Jefferies, Elizabeth; Ehsan, Sheeba; Hopper, Samantha; Lambon Ralph, Matthew A.
2009-01-01
Semantic short-term memory (STM) patients have a reduced ability to retain semantic information over brief delays but perform well on other semantic tasks; this pattern suggests damage to a dedicated buffer for semantic information. Alternatively, these difficulties may arise from mild disruption to domain-general semantic processes that have…
Reichert, B.K.; Bengtsson, L.; Oerlemans, J.
2001-01-01
A process-oriented modeling approach is applied in order to simulate glacier mass balance for individual glaciers using statistically downscaled general circulation models (GCMs). Glacier-specific seasonal sensitivity characteristics based on a mass balance model of intermediate complexity are used
Generalization of the Activated Complex Theory of Reaction Rates. II. Classical Mechanical Treatment
Marcus, R. A.
1964-01-01
In its usual classical form activated complex theory assumes a particular expression for the kinetic energy of the reacting system -- one associated with a rectilinear motion along the reaction coordinate. The derivation of the rate expression given in the present paper is based on the general kinetic energy expression.
International Nuclear Information System (INIS)
Soldatov, A.V.
2000-01-01
The Peierls-Bogolyubov inequality was generalized and a set of inequalities was derived instead, so that every subsequent inequality in this set approximates the quality in question with better precision than the preceding one. These inequalities lead to a sequence of improving upper bounds to the free energy of a quantum system if this system allows representation in terms of coherent states [ru
The general mechanisms of Cu cluster formation in the processes of ...
Indian Academy of Sciences (India)
Sci., Vol. 38, No. 3, June 2015, pp. 701–706. c Indian Academy of Sciences. ... This work represents the basic mechanisms of cluster formation from the gas phase that has been ... required, or in catalytic reactions, where the main factor of effectiveness is the .... ature of liquid nitrogen (77 K), which is used in real exper-.
Valentin, J; Sprenger, M; Pflüger, D; Röhrle, O
2018-05-01
Investigating the interplay between muscular activity and motion is the basis to improve our understanding of healthy or diseased musculoskeletal systems. To be able to analyze the musculoskeletal systems, computational models are used. Albeit some severe modeling assumptions, almost all existing musculoskeletal system simulations appeal to multibody simulation frameworks. Although continuum-mechanical musculoskeletal system models can compensate for some of these limitations, they are essentially not considered because of their computational complexity and cost. The proposed framework is the first activation-driven musculoskeletal system model, in which the exerted skeletal muscle forces are computed using 3-dimensional, continuum-mechanical skeletal muscle models and in which muscle activations are determined based on a constraint optimization problem. Numerical feasibility is achieved by computing sparse grid surrogates with hierarchical B-splines, and adaptive sparse grid refinement further reduces the computational effort. The choice of B-splines allows the use of all existing gradient-based optimization techniques without further numerical approximation. This paper demonstrates that the resulting surrogates have low relative errors (less than 0.76%) and can be used within forward simulations that are subject to constraint optimization. To demonstrate this, we set up several different test scenarios in which an upper limb model consisting of the elbow joint, the biceps and triceps brachii, and an external load is subjected to different optimization criteria. Even though this novel method has only been demonstrated for a 2-muscle system, it can easily be extended to musculoskeletal systems with 3 or more muscles. Copyright © 2018 John Wiley & Sons, Ltd.
Solving the Schroedinger equation using Smolyak interpolants
International Nuclear Information System (INIS)
Avila, Gustavo; Carrington, Tucker Jr.
2013-01-01
In this paper, we present a new collocation method for solving the Schroedinger equation. Collocation has the advantage that it obviates integrals. All previous collocation methods have, however, the crucial disadvantage that they require solving a generalized eigenvalue problem. By combining Lagrange-like functions with a Smolyak interpolant, we device a collocation method that does not require solving a generalized eigenvalue problem. We exploit the structure of the grid to develop an efficient algorithm for evaluating the matrix-vector products required to compute energy levels and wavefunctions. Energies systematically converge as the number of points and basis functions are increased
Badre, David; Wagner, Anthony D
2004-02-05
Prefrontal cortex (PFC) supports flexible behavior by mediating cognitive control, though the elemental forms of control supported by PFC remain a central debate. Dorsolateral PFC (DLPFC) is thought to guide response selection under conditions of response conflict or, alternatively, may refresh recently active representations within working memory. Lateral frontopolar cortex (FPC) may also adjudicate response conflict, though others propose that FPC supports higher order control processes such as subgoaling and integration. Anterior cingulate cortex (ACC) is hypothesized to upregulate response selection by detecting response conflict; it remains unclear whether ACC functions generalize beyond monitoring response conflict. The present fMRI experiment directly tested these competing theories regarding the functional roles of DLPFC, FPC, and ACC. Results reveal dissociable control processes in PFC, with mid-DLPFC selectively mediating resolution of response conflict and FPC further mediating subgoaling/integration. ACC demonstrated a broad sensitivity to control demands, suggesting a generalized role in modulating cognitive control.
International Nuclear Information System (INIS)
Vossier, Alexis; Gualdi, Federico; Dollet, Alain; Ares, Richard; Aimez, Vincent
2015-01-01
In principle, the upper efficiency limit of any solar cell technology can be determined using the detailed-balance limit formalism. However, “real” solar cells show efficiencies which are always below this theoretical value due to several limiting mechanisms. We study the ability of a solar cell architecture to approach its own theoretical limit, using a novel index introduced in this work, and the amplitude with which the different limiting mechanisms affect the cell efficiency is scrutinized as a function of the electronic gap and the illumination level to which the cell is submitted. The implications for future generations of solar cells aiming at an improved conversion of the solar spectrum are also addressed
Gao, Song; Zheng, Rong; Hu, Teh-wei
2012-11-01
To explain China's cigarette pricing mechanism and the role of the Chinese State Tobacco Monopoly Administration (STMA) on cigarette pricing and taxation. Published government tobacco tax documentation and statistics published by the Chinese STMA are used to analyse the interrelations among industry profits, taxes and retail price of cigarettes in China. The 2009 excise tax increase on cigarettes in China has not translated into higher retail prices because the Chinese STMA used its policy authority to ensure that retail cigarette prices did not change. The government tax increase is being collected at both the producer and wholesale levels. As a result, the 2009 excise tax increase in China has resulted in higher tax revenue for the government and lower profits for the tobacco industry, with no increase in the retail price of cigarettes for consumers. Numerous studies have found that taxation is one of the most effective policy instruments for tobacco control. However, these findings come from countries that have market economies where market forces determine prices and influence how cigarette taxes are passed to the consumers in retail prices. China's tobacco industry is not a market economy; therefore, non-market forces and the current Chinese tobacco monopoly system determine cigarette prices. The result is that tax increases do not necessarily get passed on to the retail price.
Pure states of general quantum-mechanical systems as Kaehler bundles
International Nuclear Information System (INIS)
Abbati, M.C.; Cirelli, R.; Lanzavecchia, P.; Mania, A.
1984-01-01
Pure states of general quantum systems in the Csup(*)-algebraic approach are endowed with a structure both of Kaehler manifold and of projective bundle with uniformity on the total space. The former structure gives a geometric interpretation of transition probabilities and Wigner theorem. The latter is a finer structure which determines Csup(*)-algebras up to sup(*)-isomorphisms. Pure states of Csup(*)-algebras with continuous trace among projective bundles with uniformity are characterized
Hill Clarvis, M.; Allan, A.; Hannah, D. M.
2013-12-01
Climate change has significant ramifications for water law and governance, yet, there is strong evidence that legal regulations have often failed to protect environments or promote sustainable development. Scholars have increasingly suggested that the preservation and restoration paradigms of legislation and regulation are no longer adequate for climate change related challenges in complex and cross-scale social-ecological systems. This is namely due to past assumptions of stationarity, uniformitarianism and the perception of ecosystem change as predictable and reversible. This paper reviews the literature on law and resilience and then presents and discusses a set of practical examples of legal mechanisms from the water resources management sector, identified according to a set of guiding principles from the literature on adaptive capacity, adaptive governance as well as adaptive and integrated water resources management. It then assesses the aptness of these different measures according to scientific evidence of increased uncertainty and changing ecological baselines. A review of the best practice examples demonstrates that there are a number of best practice examples attempting to integrate adaptive elements of flexibility, iterativity, connectivity and subsidiarity into a variety of legislative mechanisms, suggesting that there is not as significant a tension between resilience and the law as many scholars have suggested. However, while many of the mechanisms may indeed be suitable for addressing challenges relating to current levels of change and uncertainty, analysis across a broader range of uncertainty highlights challenges relating to more irreversible changes associated with greater levels of warming. Furthermore the paper identifies a set of pre-requisites that are fundamental to the successful implementation of such mechanisms, namely monitoring and data sharing, financial and technical capacity, particularly in nations that are most at risk with the
Lo, Janet; Plutzky, Jorge
2012-01-01
Complications of atherosclerosis, including myocardial infarction and stroke, are the leading cause of death and disability worldwide. Recent data strongly implicate cardiovascular death as a contributor to mortality among patients with human immunodeficiency virus (HIV) infection, with evidence suggesting increased incidence of atherosclerosis among these patients. Therefore, greater understanding of atherosclerotic mechanisms and how these responses may be similar or distinct in HIV-infecte...
International Nuclear Information System (INIS)
Kim, Ki Hong; Lee, Dong Hun
1999-01-01
Generalizing the work of Shapiro and Loginov, we derive new formulae of differentiation useful for solving differential equations with complex-valued random coefficients. We apply the formulae to the quantum-mechanical problem of noninteracting electrons moving in a correlated random potential in one dimension
A general mechanism for intracellular toxicity of metal-containing nanoparticles
Sabella, Stefania
2014-04-09
The assessment of the risks exerted by nanoparticles is a key challenge for academic, industrial, and regulatory communities worldwide. Experimental evidence points towards significant toxicity for a range of nanoparticles both in vitro and in vivo. Worldwide efforts aim at uncovering the underlying mechanisms for this toxicity. Here, we show that the intracellular ion release elicited by the acidic conditions of the lysosomal cellular compartment-where particles are abundantly internalized-is responsible for the cascading events associated with nanoparticles-induced intracellular toxicity. We call this mechanism a "lysosome-enhanced Trojan horse effect" since, in the case of nanoparticles, the protective cellular machinery designed to degrade foreign objects is actually responsible for their toxicity. To test our hypothesis, we compare the toxicity of similar gold particles whose main difference is in the internalization pathways. We show that particles known to pass directly through cell membranes become more toxic when modified so as to be mostly internalized by endocytosis. Furthermore, using experiments with chelating and lysosomotropic agents, we found that the toxicity mechanism for different metal containing NPs (such as metallic, metal oxide, and semiconductor NPs) is mainly associated with the release of the corresponding toxic ions. Finally, we show that particles unable to release toxic ions (such as stably coated NPs, or diamond and silica NPs) are not harmful to intracellular environments. The Royal Society of Chemistry 2014.
A general mechanism for intracellular toxicity of metal-containing nanoparticles
Sabella, Stefania; Carney, Randy P.; Brunetti, Virgilio; Malvindi, Maria Ada; Al-Juffali, Noura; Vecchio, Giuseppe; Janes, Sam M.; Bakr, Osman; Cingolani, Roberto; Stellacci, Francesco; Pompa, Pier Paolo
2014-01-01
The assessment of the risks exerted by nanoparticles is a key challenge for academic, industrial, and regulatory communities worldwide. Experimental evidence points towards significant toxicity for a range of nanoparticles both in vitro and in vivo. Worldwide efforts aim at uncovering the underlying mechanisms for this toxicity. Here, we show that the intracellular ion release elicited by the acidic conditions of the lysosomal cellular compartment-where particles are abundantly internalized-is responsible for the cascading events associated with nanoparticles-induced intracellular toxicity. We call this mechanism a "lysosome-enhanced Trojan horse effect" since, in the case of nanoparticles, the protective cellular machinery designed to degrade foreign objects is actually responsible for their toxicity. To test our hypothesis, we compare the toxicity of similar gold particles whose main difference is in the internalization pathways. We show that particles known to pass directly through cell membranes become more toxic when modified so as to be mostly internalized by endocytosis. Furthermore, using experiments with chelating and lysosomotropic agents, we found that the toxicity mechanism for different metal containing NPs (such as metallic, metal oxide, and semiconductor NPs) is mainly associated with the release of the corresponding toxic ions. Finally, we show that particles unable to release toxic ions (such as stably coated NPs, or diamond and silica NPs) are not harmful to intracellular environments. The Royal Society of Chemistry 2014.
Abraini, Jacques H; Marassio, Guillaume; David, Helene N; Vallone, Beatrice; Prangé, Thierry; Colloc'h, Nathalie
2014-11-01
The mechanisms by which general anesthetics, including xenon and nitrous oxide, act are only beginning to be discovered. However, structural approaches revealed weak but specific protein-gas interactions. To improve knowledge, we performed x-ray crystallography studies under xenon and nitrous oxide pressure in a series of 10 binding sites within four proteins. Whatever the pressure, we show (1) hydrophobicity of the gas binding sites has a screening effect on xenon and nitrous oxide binding, with a threshold value of 83% beyond which and below which xenon and nitrous oxide, respectively, binds to their sites preferentially compared to each other; (2) xenon and nitrous oxide occupancies are significantly correlated respectively to the product and the ratio of hydrophobicity by volume, indicating that hydrophobicity and volume are binding parameters that complement and oppose each other's effects; and (3) the ratio of occupancy of xenon to nitrous oxide is significantly correlated to hydrophobicity of their binding sites. These data demonstrate that xenon and nitrous oxide obey different binding mechanisms, a finding that argues against all unitary hypotheses of narcosis and anesthesia, and indicate that the Meyer-Overton rule of a high correlation between anesthetic potency and solubility in lipids of general anesthetics is often overinterpreted. This study provides evidence that the mechanisms of gas binding to proteins and therefore of general anesthesia should be considered as the result of a fully reversible interaction between a drug ligand and a receptor as this occurs in classical pharmacology.
A general mechanism for intracellular toxicity of metal-containing nanoparticles
Sabella, Stefania; Carney, Randy P.; Brunetti, Virgilio; Malvindi, Maria Ada; Al-Juffali, Noura; Vecchio, Giuseppe; Janes, Sam M.; Bakr, Osman M.; Cingolani, Roberto; Stellacci, Francesco; Pompa, Pier Paolo
2014-05-01
The assessment of the risks exerted by nanoparticles is a key challenge for academic, industrial, and regulatory communities worldwide. Experimental evidence points towards significant toxicity for a range of nanoparticles both in vitro and in vivo. Worldwide efforts aim at uncovering the underlying mechanisms for this toxicity. Here, we show that the intracellular ion release elicited by the acidic conditions of the lysosomal cellular compartment - where particles are abundantly internalized - is responsible for the cascading events associated with nanoparticles-induced intracellular toxicity. We call this mechanism a ``lysosome-enhanced Trojan horse effect'' since, in the case of nanoparticles, the protective cellular machinery designed to degrade foreign objects is actually responsible for their toxicity. To test our hypothesis, we compare the toxicity of similar gold particles whose main difference is in the internalization pathways. We show that particles known to pass directly through cell membranes become more toxic when modified so as to be mostly internalized by endocytosis. Furthermore, using experiments with chelating and lysosomotropic agents, we found that the toxicity mechanism for different metal containing NPs (such as metallic, metal oxide, and semiconductor NPs) is mainly associated with the release of the corresponding toxic ions. Finally, we show that particles unable to release toxic ions (such as stably coated NPs, or diamond and silica NPs) are not harmful to intracellular environments.The assessment of the risks exerted by nanoparticles is a key challenge for academic, industrial, and regulatory communities worldwide. Experimental evidence points towards significant toxicity for a range of nanoparticles both in vitro and in vivo. Worldwide efforts aim at uncovering the underlying mechanisms for this toxicity. Here, we show that the intracellular ion release elicited by the acidic conditions of the lysosomal cellular compartment - where
Lo, Janet; Plutzky, Jorge
2012-06-01
Complications of atherosclerosis, including myocardial infarction and stroke, are the leading cause of death and disability worldwide. Recent data strongly implicate cardiovascular death as a contributor to mortality among patients with human immunodeficiency virus (HIV) infection, with evidence suggesting increased incidence of atherosclerosis among these patients. Therefore, greater understanding of atherosclerotic mechanisms and how these responses may be similar or distinct in HIV-infected patients is needed. Key concepts in atherosclerosis are reviewed, including the evidence that inflammation and abnormal metabolism are major drivers of atherosclerosis, and connected to the current literature regarding atherosclerosis in the context of HIV.
Problem Solving in Physics: Undergraduates' Framing, Procedures, and Decision Making
Modir, Bahar
In this dissertation I will start with the broad research question of what does problem solving in upper division physics look like? My focus in this study is on students' problem solving in physics theory courses. Some mathematical formalisms are common across all physics core courses such as using the process of separation of variables, doing Taylor series, or using the orthogonality properties of mathematical functions to set terms equal to zero. However, there are slight differences in their use of these mathematical formalisms across different courses, possibly because of how students map different physical systems to these processes. Thus, my first main research question aims to answer how students perform these recurring processes across upper division physics courses. I break this broad question into three particular research questions: What knowledge pieces do students use to make connections between physics and procedural math? How do students use their knowledge pieces coherently to provide reasoning strategies in estimation problems? How do students look ahead into the problem to read the information out of the physical scenario to align their use of math in physics? Building on the previous body of the literature, I will use the theory family of Knowledge in Pieces and provide evidence to expand this theoretical foundation. I will compare my study with previous studies and provide suggestions on how to generalize these theory expansions for future use. My experimental data mostly come from video-based classroom data. Students in groups of 2-4 students solve in-class problems in quantum mechanics and electromagnetic fields 1 courses collaboratively. In addition, I will analyze clinical interviews to demonstrate how a single case study student plays an epistemic game to estimate the total energy in a hurricane. My second research question is more focused on a particular instructional context. How do students frame problem solving in quantum mechanics? I
Safi, Sher Zaman; Kumar, Selva; Ismail, Ikram Shah Bin
2014-01-01
The growing number of people with diabetes worldwide suggests that diabetic retinopathy (DR) and diabetic macular edema (DME) will continue to be sight threatening factors. The pathogenesis of diabetic retinopathy is a widespread cause of visual impairment in the world and a range of hyperglycemia-linked pathways have been implicated in the initiation and progression of this condition. Despite understanding the polyol pathway flux, activation of protein kinase C (KPC) isoforms, increased hexosamine pathway flux, and increased advanced glycation end-product (AGE) formation, pathogenic mechanisms underlying diabetes induced vision loss are not fully understood. The purpose of this paper is to review molecular mechanisms that regulate cell survival and apoptosis of retinal cells and discuss new and exciting therapeutic targets with comparison to the old and inefficient preventive strategies. This review highlights the recent advancements in understanding hyperglycemia-induced biochemical and molecular alterations, systemic metabolic factors, and aberrant activation of signaling cascades that ultimately lead to activation of a number of transcription factors causing functional and structural damage to retinal cells. It also reviews the established interventions and emerging molecular targets to avert diabetic retinopathy and its associated risk factors. PMID:25105142
Singh, Chandralekha
2009-07-01
One finding of cognitive research is that people do not automatically acquire usable knowledge by spending lots of time on task. Because students' knowledge hierarchy is more fragmented, "knowledge chunks" are smaller than those of experts. The limited capacity of short term memory makes the cognitive load high during problem solving tasks, leaving few cognitive resources available for meta-cognition. The abstract nature of the laws of physics and the chain of reasoning required to draw meaningful inferences makes these issues critical. In order to help students, it is crucial to consider the difficulty of a problem from the perspective of students. We are developing and evaluating interactive problem-solving tutorials to help students in the introductory physics courses learn effective problem-solving strategies while solidifying physics concepts. The self-paced tutorials can provide guidance and support for a variety of problem solving techniques, and opportunity for knowledge and skill acquisition.
Teaching Creative Problem Solving.
Christensen, Kip W.; Martin, Loren
1992-01-01
Interpersonal and cognitive skills, adaptability, and critical thinking can be developed through problem solving and cooperative learning in technology education. These skills have been identified as significant needs of the workplace as well as for functioning in society. (SK)
The general theory of the mechanical, electromagnetic and thermodynamic properties of black holes
International Nuclear Information System (INIS)
Carter, B.
1979-01-01
The introductory section includes a brief account of the basic mathematical concept of a black hole in a general dynamical context. This is followed by a more detailed examination of the properties of the horizon with particular reference to situations in which the black hole is allowed to tend asymptotically towards a stationary final equilibrium state. A more specialized description is then provided of the properties of the horizon in an exactly stationary state. Quasi-stationary states are next considered. The mass of a black hole is discussed. The final section summarizes the results that provide the justification for the belief that a stationary, asymptotically flat black hole state is fully determined by its mass and angular momentum when external matter and fields are absent, or by its mass, angular momentum, and electric charge if electromagnetic fields are allowed for. (U.K.)
Silber, David; Kowalski, Piotr M; Traeger, Franziska; Buchholz, Maria; Bebensee, Fabian; Meyer, Bernd; Wöll, Christof
2016-09-30
Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO 2 (110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a significant substrate-mediated interaction between adsorbates. The result is a complex superstructure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not deprotonate on the defect-free terraces of the rutile TiO 2 (110) surface.
Effect of initial bulk density on high-solids anaerobic digestion of MSW: General mechanism.
Caicedo, Luis M; Wang, Hongtao; Lu, Wenjing; De Clercq, Djavan; Liu, Yanjun; Xu, Sai; Ni, Zhe
2017-06-01
Initial bulk density (IBD) is an important variable in anaerobic digestion since it defines and optimizes the treatment capacity of a system. This study reveals the mechanism on how IBD might affect anaerobic digestion of waste. Four different IBD values: D 1 (500-700kgm -3 ), D 2 (900-1000kgm -3 ), D 3 (1100-1200kgm -3 ) and D 4 (1200-1400kgm -3 ) were set and tested over a period of 90days in simulated landfill reactors. The main variables affected by the IBD are the methane generation, saturation degree, extraction of organic matter, and the total population of methanogens. The study identified that IBD >1000kgm -3 may have significant effect on methane generation, either prolonging the lag time or completely inhibiting the process. This study provides a new understanding of the anaerobic digestion process in saturated high-solids systems. Copyright © 2017 Elsevier Ltd. All rights reserved.
Wan, Mimi; Kaundal, Ravinder; Huang, Haichang; Zhao, Jiugang; Yang, Xiaojun; Chaiyachati, Barbara H; Li, Sicong; Chi, Tian
2013-01-15
Synthetic regulatory proteins such as tetracycline (tet)-controlled transcription factors are potentially useful for repression as well as ectopic activation of endogenous genes and also for probing their regulatory mechanisms, which would offer a versatile genetic tool advantageous over conventional gene targeting methods. In this study, we provide evidence supporting this concept using Cd4 as a model. CD4 is expressed in double-positive and CD4 cells but irreversibly silenced in CD8 cells. The silencing is mediated by heterochromatin established during CD8 lineage development via transient action of the Cd4 silencer; once established, the heterochromatin becomes self-perpetuating independently of the Cd4 silencer. Using a tet-sensitive Cd4 allele harboring a removable Cd4 silencer, we found that a tet-controlled repressor recapitulated the phenotype of Cd4-deficient mice, inhibited Cd4 expression in a reversible and dose-dependent manner, and could surprisingly replace the Cd4 silencer to induce irreversible Cd4 silencing in CD8 cells, thus suggesting the Cd4 silencer is not the (only) determinant of heterochromatin formation. In contrast, a tet-controlled activator reversibly disrupted Cd4 silencing in CD8 cells. The Cd4 silencer impeded this disruption but was not essential for its reversal, which revealed a continuous role of the silencer in mature CD8 cells while exposing a remarkable intrinsic self-regenerative ability of heterochromatin after forced disruption. These data demonstrate an effective approach for gene manipulation and provide insights into the epigenetic Cd4 regulatory mechanisms that are otherwise difficult to obtain.
Severgnini, Paolo; Selmo, Gabriele; Lanza, Christian; Chiesa, Alessandro; Frigerio, Alice; Bacuzzi, Alessandro; Dionigi, Gianlorenzo; Novario, Raffaele; Gregoretti, Cesare; de Abreu, Marcelo Gama; Schultz, Marcus J; Jaber, Samir; Futier, Emmanuel; Chiaranda, Maurizio; Pelosi, Paolo
2013-06-01
The impact of intraoperative ventilation on postoperative pulmonary complications is not defined. The authors aimed at determining the effectiveness of protective mechanical ventilation during open abdominal surgery on a modified Clinical Pulmonary Infection Score as primary outcome and postoperative pulmonary function. Prospective randomized, open-label, clinical trial performed in 56 patients scheduled to undergo elective open abdominal surgery lasting more than 2 h. Patients were assigned by envelopes to mechanical ventilation with tidal volume of 9 ml/kg ideal body weight and zero-positive end-expiratory pressure (standard ventilation strategy) or tidal volumes of 7 ml/kg ideal body weight, 10 cm H2O positive end-expiratory pressure, and recruitment maneuvers (protective ventilation strategy). Modified Clinical Pulmonary Infection Score, gas exchange, and pulmonary functional tests were measured preoperatively, as well as at days 1, 3, and 5 after surgery. Patients ventilated protectively showed better pulmonary functional tests up to day 5, fewer alterations on chest x-ray up to day 3 and higher arterial oxygenation in air at days 1, 3, and 5 (mmHg; mean ± SD): 77.1 ± 13.0 versus 64.9 ± 11.3 (P = 0.0006), 80.5 ± 10.1 versus 69.7 ± 9.3 (P = 0.0002), and 82.1 ± 10.7 versus 78.5 ± 21.7 (P = 0.44) respectively. The modified Clinical Pulmonary Infection Score was lower in the protective ventilation strategy at days 1 and 3. The percentage of patients in hospital at day 28 after surgery was not different between groups (7 vs. 15% respectively, P = 0.42). A protective ventilation strategy during abdominal surgery lasting more than 2 h improved respiratory function and reduced the modified Clinical Pulmonary Infection Score without affecting length of hospital stay.
Variability in the Use of Protective Mechanical Ventilation During General Anesthesia.
Ladha, Karim S; Bateman, Brian T; Houle, Timothy T; De Jong, Myrthe A C; Vidal Melo, Marcos F; Huybrechts, Krista F; Kurth, Tobias; Eikermann, Matthias
2018-02-01
The purpose of this study was to determine whether significant variation exists in the use of protective ventilation across individual anesthesia providers and whether this difference can be explained by patient, procedure, and provider-related characteristics. The cohort consisted of 262 anesthesia providers treating 57,372 patients at a tertiary care hospital between 2007 and 2014. Protective ventilation was defined as a median positive end-expiratory pressure of 5 cm H2O or more, tidal volume of protective ventilation was modified in sensitivity analyses. In unadjusted analysis, the mean probability of administering protective ventilation was 53.8% (2.5th percentile of provider 19.9%, 97.5th percentile 80.8%). After adjustment for a large number of covariates, there was little change in the results with a mean probability of 51.1% (2.5th percentile 24.7%, 97.5th percentile 77.2%). The variations persisted when the thresholds for protective ventilation were changed. There was significant variability across individual anesthesia providers in the use of intraoperative protective mechanical ventilation. Our data suggest that this variability is highly driven by individual preference, rather than patient, procedure, or provider-related characteristics.
Fernández-de-las-Peñas, César; Arendt-Nielsen, Lars; Cuadrado, María Luz; Pareja, Juan A
2009-06-01
No study has previously analyzed pressure pain sensitivity of nerve trunks in migraine. This study aimed to examine the differences in mechanical pain sensitivity over specific nerves between patients with unilateral migraine and healthy controls. Blinded investigators assessed pressure pain thresholds (PPT) over the supra-orbital nerves (V1) and peripheral nerve trunks of both upper extremities (median, radial, and ulnar nerves) in 20 patients with strictly unilateral migraine and 20 healthy matched controls. Pain intensity after palpation over both supra-orbital nerves was also assessed. A pressure algometer was used to quantify PPT, whereas a 10-point numerical pain rate scale was used to evaluate pain to palpation over the supra-orbital nerve. The analysis of covariance revealed that pain to palpation over the supra-orbital nerve was significantly higher (P0.6). In patients with unilateral migraine, we found increased mechano-sensitivity of the supra-orbital nerve on the symptomatic side of the head. Outside the head, the same patients showed increased mechano-sensitivity of the main peripheral nerves of both upper limbs, without asymmetries. Such diffuse hypersensitivity of the peripheral nerves lends further evidence to the presence of a state of hyperexcitability of the central nervous system in patients with unilateral migraine.
Energy Technology Data Exchange (ETDEWEB)
Silenko, Alexander J. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation)
2017-05-15
A general theoretical description of a magnetic resonance is presented. This description is necessary for a detailed analysis of spin dynamics in electric-dipole-moment experiments in storage rings. General formulas describing a behavior of all components of the polarization vector at the magnetic resonance are obtained for an arbitrary initial polarization. These formulas are exact on condition that the nonresonance rotating field is neglected. The spin dynamics is also calculated at frequencies far from resonance with allowance for both rotating fields. A general quantum-mechanical analysis of the spin evolution at the magnetic resonance is fulfilled and the full agreement between the classical and quantum-mechanical approaches is shown. Quasimagnetic resonances for particles and nuclei moving in noncontinuous perturbing fields of accelerators and storage rings are considered. Distinguishing features of quasimagnetic resonances in storage ring electric-dipole-moment experiments are investigated in detail. The exact formulas for the effect caused by the electric dipole moment are derived. The difference between the resonance effects conditioned by the rf electric-field flipper and the rf Wien filter is found and is calculated for the first time. The existence of this difference is crucial for the establishment of a consent between analytical derivations and computer simulations and for checking spin tracking programs. The main systematical errors are considered. (orig.)
Sweller, John; Clark, Richard; Kirschner, Paul A.
2012-01-01
Sweller, J., Clark, R. E., & Kirschner, P. A. (2012). Ensinar capacidades gerais de resolução de problemas não é uma substituição, nem um complemento viável, a ensinar matemática [Teaching general problem-solving skills is not a substitute for, or a viable addition to, teaching mathematics]. Gazeta
Generalized theory on the mechanism of site-specific DNA-protein interactions
Niranjani, G.; Murugan, R.
2016-05-01
We develop a generalized theoretical framework on the binding of transcription factor proteins (TFs) with specific sites on DNA that takes into account the interplay of various factors regarding overall electrostatic potential at the DNA-protein interface, occurrence of kinetic traps along the DNA sequence, presence of other roadblock protein molecules along DNA and crowded environment, conformational fluctuations in the DNA binding domains (DBDs) of TFs, and the conformational state of the DNA. Starting from a Smolochowski type theoretical framework on site-specific binding of TFs we logically build our model by adding the effects of these factors one by one. Our generalized two-step model suggests that the electrostatic attractive forces present inbetween the positively charged DBDs of TFs and the negatively charged phosphate backbone of DNA, along with the counteracting shielding effects of solvent ions, is the core factor that creates a fluidic type environment at the DNA-protein interface. This in turn facilitates various one-dimensional diffusion (1Dd) processes such as sliding, hopping and intersegmental transfers. These facilitating processes as well as flipping dynamics of conformational states of DBDs of TFs between stationary and mobile states can enhance the 1Dd coefficient on a par with three-dimensional diffusion (3Dd). The random coil conformation of DNA also plays critical roles in enhancing the site-specific association rate. The extent of enhancement over the 3Dd controlled rate seems to be directly proportional to the maximum possible 1Dd length. We show that the overall site-specific binding rate scales with the length of DNA in an asymptotic way. For relaxed DNA, the specific binding rate will be independent of the length of DNA as length increases towards infinity. For condensed DNA as in in vivo conditions, the specific binding rate depends on the length of DNA in a turnover way with a maximum. This maximum rate seems to scale with the
Solving Differential Equations in R: Package deSolve
Directory of Open Access Journals (Sweden)
Karline Soetaert
2010-02-01
Full Text Available In this paper we present the R package deSolve to solve initial value problems (IVP written as ordinary differential equations (ODE, differential algebraic equations (DAE of index 0 or 1 and partial differential equations (PDE, the latter solved using the method of lines approach. The differential equations can be represented in R code or as compiled code. In the latter case, R is used as a tool to trigger the integration and post-process the results, which facilitates model development and application, whilst the compiled code significantly increases simulation speed. The methods implemented are efficient, robust, and well documented public-domain Fortran routines. They include four integrators from the ODEPACK package (LSODE, LSODES, LSODA, LSODAR, DVODE and DASPK2.0. In addition, a suite of Runge-Kutta integrators and special-purpose solvers to efficiently integrate 1-, 2- and 3-dimensional partial differential equations are available. The routines solve both stiff and non-stiff systems, and include many options, e.g., to deal in an efficient way with the sparsity of the Jacobian matrix, or finding the root of equations. In this article, our objectives are threefold: (1 to demonstrate the potential of using R for dynamic modeling, (2 to highlight typical uses of the different methods implemented and (3 to compare the performance of models specified in R code and in compiled code for a number of test cases. These comparisons demonstrate that, if the use of loops is avoided, R code can efficiently integrate problems comprising several thousands of state variables. Nevertheless, the same problem may be solved from 2 to more than 50 times faster by using compiled code compared to an implementation using only R code. Still, amongst the benefits of R are a more flexible and interactive implementation, better readability of the code, and access to R’s high-level procedures. deSolve is the successor of package odesolve which will be deprecated in
Enhanced attentional gain as a mechanism for generalized perceptual learning in human visual cortex.
Byers, Anna; Serences, John T
2014-09-01
Learning to better discriminate a specific visual feature (i.e., a specific orientation in a specific region of space) has been associated with plasticity in early visual areas (sensory modulation) and with improvements in the transmission of sensory information from early visual areas to downstream sensorimotor and decision regions (enhanced readout). However, in many real-world scenarios that require perceptual expertise, observers need to efficiently process numerous exemplars from a broad stimulus class as opposed to just a single stimulus feature. Some previous data suggest that perceptual learning leads to highly specific neural modulations that support the discrimination of specific trained features. However, the extent to which perceptual learning acts to improve the discriminability of a broad class of stimuli via the modulation of sensory responses in human visual cortex remains largely unknown. Here, we used functional MRI and a multivariate analysis method to reconstruct orientation-selective response profiles based on activation patterns in the early visual cortex before and after subjects learned to discriminate small offsets in a set of grating stimuli that were rendered in one of nine possible orientations. Behavioral performance improved across 10 training sessions, and there was a training-related increase in the amplitude of orientation-selective response profiles in V1, V2, and V3 when orientation was task relevant compared with when it was task irrelevant. These results suggest that generalized perceptual learning can lead to modified responses in the early visual cortex in a manner that is suitable for supporting improved discriminability of stimuli drawn from a large set of exemplars. Copyright © 2014 the American Physiological Society.
General load function in geo-mechanics: application to underground works
International Nuclear Information System (INIS)
Maiolino, S.
2006-04-01
This work deals both with the behavioral and numerical aspects of the mechanical response of a rock massif to the digging out of a tunnel. The comparison between existing criteria has permitted to stress on some key points, like the dependence of the criterion to the average stress and the extension ratio. A load function, easily identifiable with tests, with regular and convex properties, has been proposed which allows to take into account the shape of the Mohr envelope of the criterion and the extension ratio. Regularized forms of Mohr-Coulomb and Hoek-Brown criteria can thus be achieved. The development of this new criterion has been completed by the proposal of a numerical charts method which greatly speeds up the resolution. For the proposed criterion, the physical problem is equivalent to a purely geometrical problem in polar coordinates in the plan. Numerical charts can thus be built which allow to find immediately the value of plastic deformations and to greatly reduce the processing time. Tunnel calculation methods have been the object of a bibliographic synthesis, specifying the domains and limitations of use of tunnel dimensioning methods used by engineers. The modeling of tunnels excavation has been performed with the stationary algorithm designed for the calculation of systems submitted to mobile loads. This algorithm has been adapted to integrate the new criterion and the numerical charts system. These tools have been validated using a real case study and data supplied by the French national agency of radioactive waste management (ANDRA) in the framework of the MODEX-REP European project (5. Euratom plan). The study of these data has permitted to define a rock wear variable, easily identifiable and allowing to parameterize the damaged rock criterion. (J.S.)
Adams, Wendy Kristine
The purpose of my research was to produce a problem solving evaluation tool for physics. To do this it was necessary to gain a thorough understanding of how students solve problems. Although physics educators highly value problem solving and have put extensive effort into understanding successful problem solving, there is currently no efficient way to evaluate problem solving skill. Attempts have been made in the past; however, knowledge of the principles required to solve the subject problem are so absolutely critical that they completely overshadow any other skills students may use when solving a problem. The work presented here is unique because the evaluation tool removes the requirement that the student already have a grasp of physics concepts. It is also unique because I picked a wide range of people and picked a wide range of tasks for evaluation. This is an important design feature that helps make things emerge more clearly. This dissertation includes an extensive literature review of problem solving in physics, math, education and cognitive science as well as descriptions of studies involving student use of interactive computer simulations, the design and validation of a beliefs about physics survey and finally the design of the problem solving evaluation tool. I have successfully developed and validated a problem solving evaluation tool that identifies 44 separate assets (skills) necessary for solving problems. Rigorous validation studies, including work with an independent interviewer, show these assets identified by this content-free evaluation tool are the same assets that students use to solve problems in mechanics and quantum mechanics. Understanding this set of component assets will help teachers and researchers address problem solving within the classroom.
Vozmishcheva, Tatiana
2016-09-01
The connection between the problems of celestial mechanics: the Kepler problem, the two-center problem and the two body problem in spaces of constant curvature with the generalized Kepler and Hooke potentials is investigated. The limit passage in the two-center and two body problems in the Lobachevsky space and on a sphere is carried out as λto0 (λ is the curvature of the corresponding space) for the two potentials. The potentials and metrics in spaces under study are written in the gnomonic coordinates. It is shown that as the curvature radius tends to infinity, the generalized gravitational and elastic potentials transform to the Kepler and Hooke forms in the Euclidean space.
Directory of Open Access Journals (Sweden)
Boyuan Yan
Full Text Available Many types of epileptic seizures are characterized by generalized spike-and-wave discharges. In the past, notable effort has been devoted to understanding seizure dynamics and various hypotheses have been proposed to explain the underlying mechanisms. In this paper, by taking an integrative view of the underlying mechanisms, we demonstrate that epileptic seizures can be generated by many different combinations of synaptic strengths and intrinsic membrane properties. This integrative view has important medical implications: the specific state of a patient characterized by a set of biophysical characteristics ultimately determines the optimal therapeutic treatment. Through the same view, we further demonstrate the potentiation effect of rational polypharmacy in the treatment of epilepsy and provide a new angle to resolve the debate on polypharmacy. Our results underscore the need for personalized medicine and demonstrate that computer modeling and simulation may play an important role in assisting the clinicians in selecting the optimal treatment on an individual basis.
Huang, Xian-Rong; Peng, Ru-Wen
2010-04-01
Interactions between light and conducting microstructures or nanostructures can result in a variety of novel phenomena, but their underlying mechanisms have not been completely understood. From calculations of surface charge density waves on conducting gratings and by comparing them with classical surface plasmons, we revealed a general yet concrete picture regarding the coupling of light to free electron oscillation on structured conducting surfaces that can lead to oscillating subwavelength charge patterns (i.e., structured surface plasmons). New wavelets emitted from these light sources then destructively interfere to form evanescent waves. This principle, usually combined with other mechanisms, is mainly a geometrical effect that can be universally involved in light scattering from all periodic and non-periodic structures containing free electrons. This picture may provide clear guidelines for developing conductor-based nano-optical devices.
DEFF Research Database (Denmark)
Chemi, Tatiana
2016-01-01
This chapter aims to deconstruct some persistent myths about creativity: the myth of individualism and of the genius. By looking at literature that approaches creativity as a participatory and distributed phenomenon and by bringing empirical evidence from artists’ studios, the author presents a p......, what can educators at higher education learn from the ways creative groups solve problems? How can artists contribute to inspiring higher education?......This chapter aims to deconstruct some persistent myths about creativity: the myth of individualism and of the genius. By looking at literature that approaches creativity as a participatory and distributed phenomenon and by bringing empirical evidence from artists’ studios, the author presents...... a perspective that is relevant to higher education. The focus here is on how artists solve problems in distributed paths, and on the elements of creative collaboration. Creative problem-solving will be looked at as an ongoing dialogue that artists engage with themselves, with others, with recipients...
International Nuclear Information System (INIS)
Paraschivoiu, I.; Prud'homme, M.; Robillard, L.; Vasseur, P.
2003-01-01
This book constitutes at the same time theoretical and practical base relating to the phenomena associated with fluid mechanics. The concept of continuum is at the base of the approach developed in this work. The general advance proceeds of simple balances of forces as into hydrostatic to more complex situations or inertias, the internal stresses and the constraints of Reynolds are taken into account. This advance is not only theoretical but contains many applications in the form of solved problems, each chapter ending in a series of suggested problems. The major part of the applications relates to the incompressible flows
Generalized ladder operators for the Dirac-Coulomb problem via SUSY QM
International Nuclear Information System (INIS)
Rodrigues, R. de Lima; Universidade Federal de Campina Grande, PB
2003-12-01
The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solving the Dirac-Coulomb problem. The ground state and the excited states are investigated via new generalized ladder operators. (author)
Introspection in Problem Solving
Jäkel, Frank; Schreiber, Cornell
2013-01-01
Problem solving research has encountered an impasse. Since the seminal work of Newell und Simon (1972) researchers do not seem to have made much theoretical progress (Batchelder and Alexander, 2012; Ohlsson, 2012). In this paper we argue that one factor that is holding back the field is the widespread rejection of introspection among cognitive…
Greene, Kim; Heyck-Williams, Jeff; Timpson Gray, Elicia
2017-01-01
Problem solving spans all grade levels and content areas, as evidenced by this compilation of projects from schools across the United States. In one project, high school girls built a solar-powered tent to serve their city's homeless population. In another project, 4th graders explored historic Jamestown to learn about the voices lost to history.…
Solving Linear Differential Equations
Nguyen, K.A.; Put, M. van der
2010-01-01
The theme of this paper is to 'solve' an absolutely irreducible differential module explicitly in terms of modules of lower dimension and finite extensions of the differential field K. Representations of semi-simple Lie algebras and differential Galo is theory are the main tools. The results extend
Utomo, P.H.; Makarim, R.H.
2017-01-01
A Binary puzzle is a Sudoku-like puzzle with values in each cell taken from the set {0,1} {0,1}. Let n≥4 be an even integer, a solved binary puzzle is an n×n binary array that satisfies the following conditions: (1) no three consecutive ones and no three consecutive zeros in each row and each
Ayrinhac, Simon
2014-01-01
We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question:…
Transport equation solving methods
International Nuclear Information System (INIS)
Granjean, P.M.
1984-06-01
This work is mainly devoted to Csub(N) and Fsub(N) methods. CN method: starting from a lemma stated by Placzek, an equivalence is established between two problems: the first one is defined in a finite medium bounded by a surface S, the second one is defined in the whole space. In the first problem the angular flux on the surface S is shown to be the solution of an integral equation. This equation is solved by Galerkin's method. The Csub(N) method is applied here to one-velocity problems: in plane geometry, slab albedo and transmission with Rayleigh scattering, calculation of the extrapolation length; in cylindrical geometry, albedo and extrapolation length calculation with linear scattering. Fsub(N) method: the basic integral transport equation of the Csub(N) method is integrated on Case's elementary distributions; another integral transport equation is obtained: this equation is solved by a collocation method. The plane problems solved by the Csub(N) method are also solved by the Fsub(N) method. The Fsub(N) method is extended to any polynomial scattering law. Some simple spherical problems are also studied. Chandrasekhar's method, collision probability method, Case's method are presented for comparison with Csub(N) and Fsub(N) methods. This comparison shows the respective advantages of the two methods: a) fast convergence and possible extension to various geometries for Csub(N) method; b) easy calculations and easy extension to polynomial scattering for Fsub(N) method [fr
Dobbs, David E.
2013-01-01
A direct method is given for solving first-order linear recurrences with constant coefficients. The limiting value of that solution is studied as "n to infinity." This classroom note could serve as enrichment material for the typical introductory course on discrete mathematics that follows a calculus course.
International Nuclear Information System (INIS)
Kraatz-Wadsack, G.
2009-01-01
The United Nations Global Counter-Terrorism Strategy was adopted by the UN General Assembly in September 2006. Preventing and responding to attacks using WMD were identified amongst the key areas of activities covered by the strategy. The Secretary-General's mechanism to carry out prompt investigations in response to allegations brought to his attention concerning the possible use of chemical and bacteriological (biological) and toxin weapons was developed in the late 1980s. Triggered by a request from any member State, the Secretary-General is authorized to launch an investigation including dispatching a fact-finding team to the site of the alleged incident(s) and to report to all UN Member States. This is to ascertain in an objective and scientific manner facts of alleged violations of the 1925 Geneva Protocol, which bans the use of chemical and biological weapons. Member States encouraged the Secretary-General in September 2006 to update the roster of experts and laboratories, as well as the technical guidelines and procedures, available to him for the timely and efficient investigation of alleged use. The roster of experts and laboratories and the guidelines and procedures constitute the key elements of the special mechanism available to the Secretary-General for investigation of reports by Member States of alleged use of chemical, biological and toxin weapons. The Office for Disarmament Affairs has been working with Member States since March 2007 to update the roster of experts and laboratories and the technical appendices of the guidelines and procedures so that they fully correspond with the rapid and substantial developments that have occurred in the biological area since the 1980s and also to take into account the fact that an Organization for the Prohibition of Chemical Weapons (OPCW) has since been established. Currently, the roster of experts and laboratories has been updated and includes experts from more than 50 countries. The information available in
Energy Technology Data Exchange (ETDEWEB)
Kraatz-Wadsack, G [Department for Disarmament Affairs at the United Nations, UN Office for Disarmament Affairs (UNODA), New York (United States)
2009-07-01
The United Nations Global Counter-Terrorism Strategy was adopted by the UN General Assembly in September 2006. Preventing and responding to attacks using WMD were identified amongst the key areas of activities covered by the strategy. The Secretary-General's mechanism to carry out prompt investigations in response to allegations brought to his attention concerning the possible use of chemical and bacteriological (biological) and toxin weapons was developed in the late 1980s. Triggered by a request from any member State, the Secretary-General is authorized to launch an investigation including dispatching a fact-finding team to the site of the alleged incident(s) and to report to all UN Member States. This is to ascertain in an objective and scientific manner facts of alleged violations of the 1925 Geneva Protocol, which bans the use of chemical and biological weapons. Member States encouraged the Secretary-General in September 2006 to update the roster of experts and laboratories, as well as the technical guidelines and procedures, available to him for the timely and efficient investigation of alleged use. The roster of experts and laboratories and the guidelines and procedures constitute the key elements of the special mechanism available to the Secretary-General for investigation of reports by Member States of alleged use of chemical, biological and toxin weapons. The Office for Disarmament Affairs has been working with Member States since March 2007 to update the roster of experts and laboratories and the technical appendices of the guidelines and procedures so that they fully correspond with the rapid and substantial developments that have occurred in the biological area since the 1980s and also to take into account the fact that an Organization for the Prohibition of Chemical Weapons (OPCW) has since been established. Currently, the roster of experts and laboratories has been updated and includes experts from more than 50 countries. The information available in
Directory of Open Access Journals (Sweden)
Adekemi O. Sekoni
2012-11-01
Objectives: This study assessed the various domains of stigma experienced by PLWHAs attending an HIV clinic at General Hospital, Lagos Island, their medication adherence patterns and their coping mechanisms for ensuring adherence to antiretroviral therapy. Method: A cross-sectional study design with a sample size of 200 was used. Respondents were selected using systematic random sampling. Interviewers administered structured questionnaires were used to collect information on the domains of stigma. Data was analysed using EPI info©. This was followed by a focus group discussion (FGD with seven participants at the clinic using an interview guide with open-ended questions. Results: Overall, stigma was experienced by 35% of the respondents. Within this group, 6.6%, 37.1%, 43.1% and 98.0% of the respondents reported experiencing negative self image stigma, personalised stigma, disclosure stigma and public attitude stigma respectively. Almost 90% of the respondents were adherent. The FGD revealed that disclosure was usually confined to family members and the coping mechanism for achieving adherence was to put antiretroviral (ARVs in unlabelled pill boxes. Conclusion: This study found that stigma was low and that the most common domain of stigma experienced was public attitude stigma. Medication adherence of respondents was good as a result of the coping mechanism, which involves putting ARVs in unlabelled pill boxes.
Toward Solving the Problem of Problem Solving: An Analysis Framework
Roesler, Rebecca A.
2016-01-01
Teaching is replete with problem solving. Problem solving as a skill, however, is seldom addressed directly within music teacher education curricula, and research in music education has not examined problem solving systematically. A framework detailing problem-solving component skills would provide a needed foundation. I observed problem solving…
Chang, Zhiwei; Halle, Bertil
2016-02-28
In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. We have embarked on a systematic program to develop, from the stochastic Liouville equation, a general and rigorous theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole coupling strengths, and Larmor frequencies. Here, we present a general theoretical framework applicable to spin systems of arbitrary size with symmetric or asymmetric exchange. So far, the dipolar EMOR theory is only available for a two-spin system with symmetric exchange. Asymmetric exchange, when the spin system is fragmented by the exchange, introduces new and unexpected phenomena. Notably, the anisotropic dipole couplings of non-exchanging spins break the axial symmetry in spin Liouville space, thereby opening up new relaxation channels in the locally anisotropic sites, including longitudinal-transverse cross relaxation. Such cross-mode relaxation operates only at low fields; at higher fields it becomes nonsecular, leading to an unusual inverted relaxation dispersion that splits the extreme-narrowing regime into two sub-regimes. The general dipolar EMOR theory is illustrated here by a detailed analysis of the asymmetric two-spin case, for which we present relaxation dispersion profiles over a wide range of conditions as well as analytical results for integral relaxation rates and time-dependent spin modes in the zero-field and motional-narrowing regimes. The general theoretical framework presented here will enable a quantitative analysis of frequency-dependent water-proton longitudinal relaxation in model systems with immobilized macromolecules and, ultimately, will provide a rigorous link between relaxation-based magnetic resonance image contrast and molecular parameters.
Student Obstacles in Solving Algebraic Thinking Problems
Andini, W.; Suryadi, D.
2017-09-01
The aim of this research is to analize the student obstacles on solving algebraic thinking problems in low grades elementary school. This research is a preliminary qualitative research, and involved 66 students of grade 3 elementary school. From the analysis student test results, most of student experience difficulty in solving algebraic thinking problems. The main obstacle is the student’s difficulty in understanding the problem of generalizing the pattern because the students are not accustomed to see the rules that exist in generalize the pattern.
Creativity and Problem Solving
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui
2004-01-01
This paper presents some modern and interdisciplinary concepts about creativity and creative processes of special relevance for Operational Research workers. Central publications in the area Creativity-Operational Research are shortly reviewed. Some creative tools and the Creative Problem Solving...... approach are also discussed. Finally, some applications of these concepts and tools are outlined. Some central references are presented for further study of themes related to creativity or creative tools....
Creativity and problem Solving
Directory of Open Access Journals (Sweden)
René Victor Valqui Vidal
2004-12-01
Full Text Available This paper presents some modern and interdisciplinary concepts about creativity and creative processes of special relevance for Operational Research workers. Central publications in the area Creativity-Operational Research are shortly reviewed. Some creative tools and the Creative Problem Solving approach are also discussed. Finally, some applications of these concepts and tools are outlined. Some central references are presented for further study of themes related to creativity or creative tools.
Directory of Open Access Journals (Sweden)
D. S. Blinov
2017-01-01
Full Text Available The most important trend in the development of aerospace industry is to increase load capacity of mechanisms, assemblies, and parts without increasing their size and weight. The above is also true for widely used in aircrafts and the most promising up to date Epicyclic Roller-Screw Mechanisms (ERSM that convert rotational movement into translational one. Previously (in the article, it was proposed to increase the load capacity (approximately by 15% through reduction of included angle of ERSM threaded parts from 90° to 70°.However, such improvement of ERSM will change dimensions of the mechanism parts and its parameters and characteristics (efficiency factor, position of initial point of contact of the conjugated thread turns and parameters of their contact interaction, as well as kinematic parameters, which will require additional studies. If we take into account the priority of these studies, then surely we must begin with development of technique to determine dimensions of the ERSM main parts and their tolerance zones because we need drawings to manufacture and test the upgraded ERSM. We have developed a technique to calculate dimensions of the main parts of ERSM and associated tolerance zones that takes in to account the change of included angle of threaded parts of the mechanism and radius of circular arc according to which roller thread profile has been fulfilled. So the proposed technique is the general one in comparison with the previous ones.This technique uses various conditions and equations to determine dimensions of parts and associated tolerance zones. For example, a nut encircles a screw with rollers, and their dimensions form a closed dimension chain, in which the dimensions and associated tolerances must be such as to ensure ERSM assembling, on the one hand, and, on the other hand the backlash of the mechanism should be minimal to ensure high load capacity, kinematic accuracy, and rigidity of ERSM. We used the following
Energy Technology Data Exchange (ETDEWEB)
Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2016-09-30
The iron-based, iron-chromium-aluminum (FeCrAl) alloys are promising, robust materials for deployment in current and future nuclear power plants. This class of alloys demonstrates excellent performance in a range of environments and conditions, including high-temperature steam (>1000°C). Furthermore, these alloys have the potential to have prolonged survival under loss-of-coolant accident (LOCA) conditions compared to the more traditional cladding materials that are either Zr-based alloys or austenitic steels. However, one of the issues associated with FeCrAl alloys is cracking during welding. The present project investigates the possibility of mitigating welding-induced cracking via alloying and precise structure control of the weldments; in the frame work of the project, several advanced alloys were developed and are being investigated prior to and after neutron irradiation to provide insight into the radiation tolerance and mechanical performance of the weldments. The present report provides preliminary results on the post-irradiation characterization and mechanical tests performed during United States Fiscal Year (FY) 2016. Chapter 1 provides a general introduction, and Chapter 2 describes the alloy compositions, welding procedure, specimen geometry and manufacturing parameters. Also, a brief discussion of the irradiation at the High Flux Isotope Reactor (HFIR) is provided. Chapter 3 is devoted to the analysis of mechanical tests performed at the hot cell facility; tensile curves and mechanical properties are discussed in detail focusing on the irradiation temperature. Limited fractography results are also presented and analyzed. The discussion highlights the limitations of the testing within a hot cell. Chapter 4 underlines the advantages of in-situ testing and discusses the preliminary results obtained with newly developed miniature specimens. Specimens were moved to the Low Activation Materials Development and Analysis (LAMDA) laboratory and prepared for
Dissociation of past and present experience in problem solving using a virtual environment.
Sturz, Bradley R; Bodily, Kent D; Katz, Jeffrey S
2009-02-01
An interactive 3D desktop virtual environment task was created to investigate learning mechanisms in human problem solving. Participants were assessed for previous video game experience, divided into two groups (Training and Control), and matched for gender and experience. The Training group learned specific skills within the virtual environment before being presented a problem. The Control group was presented the problem only. Completion time was faster for the Training group and was affected by level of previous video game experience. Results indicated problem solving was a function of specific and general experience and demonstrated a method for dissociating these two facets of experience.
General Intelligence Predicts Reasoning Ability Even for Evolutionarily Familiar Content
Kaufman, Scott Barry; DeYoung, Colin G.; Reis, Deidre L.; Gray, Jeremy R.
2011-01-01
The existence of general-purpose cognitive mechanisms related to intelligence, which appear to facilitate all forms of problem solving, conflicts with the strong modularity view of the mind espoused by some evolutionary psychologists. The current study assessed the contribution of general intelligence ("g") to explaining variation in…
D'Ulivo, Alessandro
2016-05-01
A reaction model describing the reactivity of metal and semimetal species with aqueous tetrahydridoborate (THB) has been drawn taking into account the mechanism of chemical vapor generation (CVG) of hydrides, recent evidences on the mechanism of interference and formation of byproducts in arsane generation, and other evidences in the field of the synthesis of nanoparticles and catalytic hydrolysis of THB by metal nanoparticles. The new "non-analytical" reaction model is of more general validity than the previously described "analytical" reaction model for CVG. The non-analytical model is valid for reaction of a single analyte with THB and for conditions approaching those typically encountered in the synthesis of nanoparticles and macroprecipitates. It reduces to the previously proposed analytical model under conditions typically employed in CVG for trace analysis (analyte below the μM level, borane/analyte ≫ 103 mol/mol, no interference). The non-analytical reaction model is not able to explain all the interference effects observed in CVG, which can be achieved only by assuming the interaction among the species of reaction pathways of different analytical substrates. The reunification of CVG, the synthesis of nanoparticles by aqueous THB and the catalytic hydrolysis of THB inside a common frame contribute to rationalization of the complex reactivity of aqueous THB with metal and semimetal species.
Montuoro, Paul; Mainhard, Tim
2017-12-01
Considerable research has investigated the deleterious effects of teachers responding aggressively to students who misbehave, but the mechanism underlying this dysfunctional behaviour remains unknown. This study investigated whether the mechanism underlying teacher aggression follows I 3 theory or General Aggression Model (GAM) metatheory of human aggression. I 3 theory explains exceptional, catastrophic events of human aggression, whereas the GAM explains common human aggression behaviours. A total of 249 Australian teachers participated in this study, including 142 primary school teachers (Mdn [age] = 35-39 years; Mdn [years teaching] = 10-14 years; 84% female) and 107 secondary school teachers (Mdn [age] = 45-49 years; Mdn [years teaching] = 15-19 years; 65% female). Participants completed four online self-report questionnaires, which assessed caregiving responsiveness, trait self-control, misbehaviour provocation, and teacher aggression. Analyses revealed that the GAM most accurately captures the mechanism underlying teacher aggression, with lower caregiving responsiveness appearing to indirectly lead to teacher aggression via higher misbehaviour provocation and lower trait self-control in serial, controlling for gender, age, years teaching, and current role (primary, secondary). This study indicates that teacher aggression proceeds from 'the person in the situation'. Specifically, lower caregiving responsiveness appears to negatively shape a teacher's affective, cognitive, and arousal states, which influence how they perceive and interpret student misbehaviour. These internal states, in turn, appear to negatively influence appraisal and decision processes, leading to immediate appraisal and impulsive actions. These results raise the possibility that teacher aggression is a form of countertransference. © 2017 The British Psychological Society.
International Nuclear Information System (INIS)
Marchetti-Sillans, L.
2007-11-01
In France, nickel base alloys, such as alloy 600 and alloy 690, are the materials constituting steam generators (SG) tubes of pressurized water reactors (PWR). The generalized corrosion resulting from the interaction between these alloys and the PWR primary media leads, on the one hand, to the formation of a thin protective oxide scale (∼ 10 nm), and on the other hand, to the release of cations in the primary circuit, which entails an increase of the global radioactivity of this circuit. The goal of this work is to supply some new comprehension elements about nickel base alloys corrosion phenomena in PWR primary media, taking up with underlining the effects of metallurgical and physico-chemical parameters on the nature and the growth mechanisms of the protective oxide scale. In this context, the passive film formed during the exposition of alloys 600, 690 and Ni-30Cr, in conditions simulating the PWR primary media, has been analyzed by a set of characterization techniques (SEM, TEM, PEC and MPEC, XPS). The coupling of these methods leads to a fine description, in terms of nature and structure, of the multilayered oxide forming during the exposition of nickel base alloys in primary media. Thus, the protective part of the oxide scale is composed of a continuous layer of iron and nickel mixed chromite, and Cr 2 O 3 nodules dispersed at the alloy / mixed chromite interface. The study of protective scale growth mechanisms by tracers and markers experiments reveals that the formation of the mixed chromite is the consequence of an anionic mechanism, resulting from short circuits like grain boundaries diffusion. Besides, the impact of alloy surface defects has also been studied, underlining a double effect of this parameter, which influences the short circuits diffusion density in oxide and the formation rate of Cr 2 O 3 nodules. The sum of these results leads to suggest a description of the nickel base alloys corrosion mechanisms in PWR primary media and to tackle some
DEFF Research Database (Denmark)
Hansen, David
2012-01-01
Many industrial production work systems have increased in complexity, and their new business model scompete on innovation, rather than low cost.At a medical device production facility committed to Lean Production, a research project was carried out to use Appreciative Inquiry to better engage...... employee strengths in continuou simprovements of the work system. The research question was: “How can Lean problem solving and Appreciative Inquiry be combined for optimized work system innovation?” The research project was carried out as a co-creation process with close cooperation between researcher...
1982-10-01
Artificial Intelig ~ence (Vol. III, edited by Paul R. Cohen and’ Edward A.. Feigenbaum)’, The chapter was written B’ Paul Cohen, with contributions... Artificial Intelligence (Vol. III, edited by Paul R. Cohen and EdWard A. Feigenbaum). The chapter was written by Paul R. Cohen, with contributions by Stephen...Wheevoats"EntermdI’ Planning and Problem ’Solving by Paul R. Cohen Chaptb-rXV-of Volumec III’of the Handbook of Artificial Intelligence edited by Paul R
A Microgenetic Study of Insightful Problem Solving
Luwel, Koen; Siegler, Robert S.; Verschaffel, Lieven
2008-01-01
An eight-session microgenetic study of acquisition of an insightful problem-solving strategy was conducted. A total of 35 second graders who did not use this insightful strategy initially were assigned to two groups that differed in the frequency of problems likely to facilitate discovery and generalization of the strategy. Children in the…
Discovering Steiner Triple Systems through Problem Solving
Sriraman, Bharath
2004-01-01
An attempt to implement problem solving as a teacher of ninth grade algebra is described. The problems selected were not general ones, they involved combinations and represented various situations and were more complex which lead to the discovery of Steiner triple systems.
A reflexive perspective in problem solving
Chio, José Angel; Álvarez, Aida; López, Margarita
2013-01-01
The objective of this paper is to favour the methodological process of reflexive analysis in problem solving in the general teaching methods that concentrates in strengthening the dimensional analysis, to gain a greater preparation of the students for the solution of mathematical problems.
Solving Differential Equations in R: Package deSolve
In this paper we present the R package deSolve to solve initial value problems (IVP) written as ordinary differential equations (ODE), differential algebraic equations (DAE) of index 0 or 1 and partial differential equations (PDE), the latter solved using the method of lines appr...
Solving Differential Equations in R: Package deSolve
Soetaert, K.E.R.; Petzoldt, T.; Setzer, R.W.
2010-01-01
In this paper we present the R package deSolve to solve initial value problems (IVP) written as ordinary differential equations (ODE), differential algebraic equations (DAE) of index 0 or 1 and partial differential equations (PDE), the latter solved using the method of lines approach. The
Pawaskar, Sainath Shrikant; Fisher, John; Jin, Zhongmin
2010-03-01
Contact detection in cartilage contact mechanics is an important feature of any analytical or computational modeling investigation when the biphasic nature of cartilage and the corresponding tribology are taken into account. The fluid flow boundary conditions will change based on whether the surface is in contact or not, which will affect the interstitial fluid pressurization. This in turn will increase or decrease the load sustained by the fluid phase, with a direct effect on friction, wear, and lubrication. In laboratory experiments or clinical hemiarthroplasty, when a rigid indenter or metallic prosthesis is used to apply load to the cartilage, there will not be any fluid flow normal to the surface in the contact region due to the impermeable nature of the indenter/prosthesis. In the natural joint, on the other hand, where two cartilage surfaces interact, flow will depend on the pressure difference across the interface. Furthermore, in both these cases, the fluid would flow freely in non-contacting regions. However, it should be pointed out that the contact area is generally unknown in advance in both cases and can only be determined as part of the solution. In the present finite element study, a general and robust algorithm was proposed to decide nodes in contact on the cartilage surface and, accordingly, impose the fluid flow boundary conditions. The algorithm was first tested for a rigid indenter against cartilage model. The algorithm worked well for two-dimensional four-noded and eight-noded axisymmetric element models as well as three-dimensional models. It was then extended to include two cartilages in contact. The results were in excellent agreement with the previous studies reported in the literature.
Diagrams benefit symbolic problem-solving.
Chu, Junyi; Rittle-Johnson, Bethany; Fyfe, Emily R
2017-06-01
The format of a mathematics problem often influences students' problem-solving performance. For example, providing diagrams in conjunction with story problems can benefit students' understanding, choice of strategy, and accuracy on story problems. However, it remains unclear whether providing diagrams in conjunction with symbolic equations can benefit problem-solving performance as well. We tested the impact of diagram presence on students' performance on algebra equation problems to determine whether diagrams increase problem-solving success. We also examined the influence of item- and student-level factors to test the robustness of the diagram effect. We worked with 61 seventh-grade students who had received 2 months of pre-algebra instruction. Students participated in an experimenter-led classroom session. Using a within-subjects design, students solved algebra problems in two matched formats (equation and equation-with-diagram). The presence of diagrams increased equation-solving accuracy and the use of informal strategies. This diagram benefit was independent of student ability and item complexity. The benefits of diagrams found previously for story problems generalized to symbolic problems. The findings are consistent with cognitive models of problem-solving and suggest that diagrams may be a useful additional representation of symbolic problems. © 2017 The British Psychological Society.
Narooei, K; Arman, M
2018-03-01
In this research, the exponential stretched based hyperelastic strain energy was generalized to the hyper-viscoelastic model using the heredity integral of deformation history to take into account the strain rate effects on the mechanical behavior of materials. The heredity integral was approximated by the approach of Goh et al. to determine the model parameters and the same estimation was used for constitutive modeling. To present the ability of the proposed hyper-viscoelastic model, the stress-strain response of the thermoplastic elastomer gel tissue at different strain rates from 0.001 to 100/s was studied. In addition to better agreement between the current model and experimental data in comparison to the extended Mooney-Rivlin hyper-viscoelastic model, a stable material behavior was predicted for pure shear and balance biaxial deformation modes. To present the engineering application of current model, the Kolsky bars impact test of gel tissue was simulated and the effects of specimen size and inertia on the uniform deformation were investigated. As the mechanical response of polyurea was provided over wide strain rates of 0.0016-6500/s, the current model was applied to fit the experimental data. The results were shown more accuracy could be expected from the current research than the extended Ogden hyper-viscoelastic model. In the final verification example, the pig skin experimental data was used to determine parameters of the hyper-viscoelastic model. Subsequently, a specimen of pig skin at different strain rates was loaded to a fixed strain and the change of stress with time (stress relaxation) was obtained. The stress relaxation results were revealed the peak stress increases by applied strain rate until the saturated loading rate and the equilibrium stress with magnitude of 0.281MPa could be reached. Copyright © 2017 Elsevier Ltd. All rights reserved.
Conceptual problem solving in high school physics
Docktor, Jennifer L.; Strand, Natalie E.; Mestre, José P.; Ross, Brian H.
2015-12-01
Problem solving is a critical element of learning physics. However, traditional instruction often emphasizes the quantitative aspects of problem solving such as equations and mathematical procedures rather than qualitative analysis for selecting appropriate concepts and principles. This study describes the development and evaluation of an instructional approach called Conceptual Problem Solving (CPS) which guides students to identify principles, justify their use, and plan their solution in writing before solving a problem. The CPS approach was implemented by high school physics teachers at three schools for major theorems and conservation laws in mechanics and CPS-taught classes were compared to control classes taught using traditional problem solving methods. Information about the teachers' implementation of the approach was gathered from classroom observations and interviews, and the effectiveness of the approach was evaluated from a series of written assessments. Results indicated that teachers found CPS easy to integrate into their curricula, students engaged in classroom discussions and produced problem solutions of a higher quality than before, and students scored higher on conceptual and problem solving measures.
Conceptual problem solving in high school physics
Directory of Open Access Journals (Sweden)
Jennifer L. Docktor
2015-09-01
Full Text Available Problem solving is a critical element of learning physics. However, traditional instruction often emphasizes the quantitative aspects of problem solving such as equations and mathematical procedures rather than qualitative analysis for selecting appropriate concepts and principles. This study describes the development and evaluation of an instructional approach called Conceptual Problem Solving (CPS which guides students to identify principles, justify their use, and plan their solution in writing before solving a problem. The CPS approach was implemented by high school physics teachers at three schools for major theorems and conservation laws in mechanics and CPS-taught classes were compared to control classes taught using traditional problem solving methods. Information about the teachers’ implementation of the approach was gathered from classroom observations and interviews, and the effectiveness of the approach was evaluated from a series of written assessments. Results indicated that teachers found CPS easy to integrate into their curricula, students engaged in classroom discussions and produced problem solutions of a higher quality than before, and students scored higher on conceptual and problem solving measures.
Energy Technology Data Exchange (ETDEWEB)
Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2016-06-03
The present report summarizes and discusses the preliminary results for the in-depth characterization of the modern, nuclear-grade FeCrAl alloys currently under development. The alloys were designed for enhanced radiation tolerance and weldability, and the research is currently being pursued by the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program. Last year, seven candidate FeCrAl alloys with well-controlled chemistry and microstructures were designed and produced; welding was performed under well-controlled conditions. The structure and general performance of unirradiated alloys were assessed using standardized and advanced microstructural characterization techniques and mechanical testing. The primary objective is to identify the best candidate alloy, or at a minimum to identify the contributing factors that increase the weldability and radiation tolerance of FeCrAl alloys, therefore enabling future generations of FeCrAl alloys to deliver better performance parameters. This report is structured so as to describe these critical assessments of the weldability; radiation tolerance will be reported on in later reports from this program.
International Nuclear Information System (INIS)
Gross, D.H.E.
2006-01-01
Heat can flow from cold to hot at any phase separation even in macroscopic systems. Therefore also Lynden-Bell's famous gravo-thermal catastrophe must be reconsidered. In contrast to traditional canonical Boltzmann-Gibbs statistics this is correctly described only by microcanonical statistics. Systems studied in chemical thermodynamics (ChTh) by using canonical statistics consist of several homogeneous macroscopic phases. Evidently, macroscopic statistics as in chemistry cannot and should not be applied to non-extensive or inhomogeneous systems like nuclei or galaxies. Nuclei are small and inhomogeneous. Multifragmented nuclei are even more inhomogeneous and the fragments even smaller. Phase transitions of first order and especially phase separations therefore cannot be described by a (homogeneous) canonical ensemble. Taking this serious, fascinating perspectives open for statistical nuclear fragmentation as test ground for the basic principles of statistical mechanics, especially of phase transitions, without the use of the thermodynamic limit. Moreover, there is also a lot of similarity between the accessible phase space of fragmenting nuclei and inhomogeneous multistellar systems. This underlines the fundamental significance for statistical physics in general. (orig.)
Solved problems in electromagnetics
Salazar Bloise, Félix; Bayón Rojo, Ana; Gascón Latasa, Francisco
2017-01-01
This book presents the fundamental concepts of electromagnetism through problems with a brief theoretical introduction at the beginning of each chapter. The present book has a strong didactic character. It explains all the mathematical steps and the theoretical concepts connected with the development of the problem. It guides the reader to understand the employed procedures to learn to solve the exercises independently. The exercises are structured in a similar way: The chapters begin with easy problems increasing progressively in the level of difficulty. This book is written for students of physics and engineering in the framework of the new European Plans of Study for Bachelor and Master and also for tutors and lecturers. .
Solved problems in electrochemistry
International Nuclear Information System (INIS)
Piron, D.L.
2004-01-01
This book presents calculated solutions to problems in fundamental and applied electrochemistry. It uses industrial data to illustrate scientific concepts and scientific knowledge to solve practical problems. It is subdivided into three parts. The first uses modern basic concepts, the second studies the scientific basis for electrode and electrolyte thermodynamics (including E-pH diagrams and the minimum energy involved in transformations) and the kinetics of rate processes (including the energy lost in heat and in parasite reactions). The third part treats larger problems in electrolysis and power generation, as well as in corrosion and its prevention. Each chapter includes three sections: the presentation of useful principles; some twenty problems with their solutions; and, a set of unsolved problems
Problem solving with genetic algorithms and Splicer
Bayer, Steven E.; Wang, Lui
1991-01-01
Genetic algorithms are highly parallel, adaptive search procedures (i.e., problem-solving methods) loosely based on the processes of population genetics and Darwinian survival of the fittest. Genetic algorithms have proven useful in domains where other optimization techniques perform poorly. The main purpose of the paper is to discuss a NASA-sponsored software development project to develop a general-purpose tool for using genetic algorithms. The tool, called Splicer, can be used to solve a wide variety of optimization problems and is currently available from NASA and COSMIC. This discussion is preceded by an introduction to basic genetic algorithm concepts and a discussion of genetic algorithm applications.
New method for solving multidimensional scattering problem
International Nuclear Information System (INIS)
Melezhik, V.S.
1991-01-01
A new method is developed for solving the quantum mechanical problem of scattering of a particle with internal structure. The multichannel scattering problem is formulated as a system of nonlinear functional equations for the wave function and reaction matrix. The method is successfully tested for the scattering from a nonspherical potential well and a long-range nonspherical scatterer. The method is also applicable to solving the multidimensional Schroedinger equation with a discrete spectrum. As an example the known problem of a hydrogen atom in a homogeneous magnetic field is analyzed
Hartog, J P Den
1961-01-01
First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e
Montuoro, Paul; Mainhard, Tim
2017-01-01
Background: Considerable research has investigated the deleterious effects of teachers responding aggressively to students who misbehave, but the mechanism underlying this dysfunctional behaviour remains unknown. Aims: This study investigated whether the mechanism underlying teacher aggression
Şengül, Caner
2016-01-01
College Mechanics QueBank has been designed to be different, enthusiastic, interesting and helpful to you. Therefore, it is not just a test bank about mechanics but also it is like a compass in order to find your way in mechanics Each chapter in this book is put in an order to follow a hierarchy of the mechanics topics; from vectors to simple harmonic motion. Throughout the book there are many multiple choice and long answer questions for you to solve. They have been created for YGS, LYS, SAT, IB or other standardized exams in the world because mechanics has no boundaries and so Physics has no country. Learn the main principle of each chapter and explore the daily life applications. Then you can start to solve the questions by planning a problem solving method carefully. Finally, enjoy solving the questions and discover the meachanics of the universe once more.
Applying homotopy analysis method for solving differential-difference equation
International Nuclear Information System (INIS)
Wang Zhen; Zou Li; Zhang Hongqing
2007-01-01
In this Letter, we apply the homotopy analysis method to solving the differential-difference equations. A simple but typical example is applied to illustrate the validity and the great potential of the generalized homotopy analysis method in solving differential-difference equation. Comparisons are made between the results of the proposed method and exact solutions. The results show that the homotopy analysis method is an attractive method in solving the differential-difference equations
Mander, Johannes V; Jacob, Gitta A; Götz, Lea; Sammet, Isa; Zipfel, Stephan; Teufel, Martin
2015-01-01
The study aimed at analyzing associations between Grawe's general mechanisms of change and Young's early maladaptive schemas (EMS). Therefore, 98 patients completed the Scale for the Multiperspective Assessment of General Change Mechanisms in Psychotherapy (SACiP), the Young Shema Questionnaire-Short Form Revised (YSQ S3R), and diverse outcome measures at the beginning and end of treatment. Our results are important for clinical applications, as we demonstrated strong predictive effects of change mechanisms on schema domains using regression analyses and cross-lagged panel models. Resource activation experiences seem to be especially crucial in fostering alterations in EMS, as this change mechanism demonstrated significant associations with several schema domains. Future research should investigate these aspects in more detail using observer-based micro-process analyses.
Klenke, Andrew M.; Dell, Tim W.
2007-01-01
Graduates of the automotive technology program at Pittsburg State University (PSU) generally enter the workforce in some type of automotive management role. As a result, the program does not require students to purchase their own tools, and it does not have room for all 280 majors to roll around a personal tool chest. Each instructor must maintain…
Solving the uncalibrated photometric stereo problem using total variation
DEFF Research Database (Denmark)
Quéau, Yvain; Lauze, Francois Bernard; Durou, Jean-Denis
2013-01-01
In this paper we propose a new method to solve the problem of uncalibrated photometric stereo, making very weak assumptions on the properties of the scene to be reconstructed. Our goal is to solve the generalized bas-relief ambiguity (GBR) by performing a total variation regularization of both...
Is Word-Problem Solving a Form of Text Comprehension?
Fuchs, Lynn S.; Fuchs, Douglas; Compton, Donald L.; Hamlett, Carol L.; Wang, Amber Y.
2015-01-01
This study's hypotheses were that (a) word-problem (WP) solving is a form of text comprehension that involves language comprehension processes, working memory, and reasoning, but (b) WP solving differs from other forms of text comprehension by requiring WP-specific language comprehension as well as general language comprehension. At the start of…
International Nuclear Information System (INIS)
Khorrami, M.
1995-01-01
A general formulation for discrete-time quantum mechanics, based on Feynman's method in ordinary quantum mechanics, is presented. It is shown that the ambiguities present in ordinary quantum mechanics (due to noncommutativity of the operators), are no longer present here. Then the criteria for the unitarity of the evolution operator are examined. It is shown that the unitarity of the evolution operator puts restrictions on the form of the action, and also implies the existence of a solution for the classical initial-value problem. 13 refs
Noncommutative quantum mechanics
Gamboa, J.; Loewe, M.; Rojas, J. C.
2001-09-01
A general noncommutative quantum mechanical system in a central potential V=V(r) in two dimensions is considered. The spectrum is bounded from below and, for large values of the anticommutative parameter θ, we find an explicit expression for the eigenvalues. In fact, any quantum mechanical system with these characteristics is equivalent to a commutative one in such a way that the interaction V(r) is replaced by V=V(HHO,Lz), where HHO is the Hamiltonian of the two-dimensional harmonic oscillator and Lz is the z component of the angular momentum. For other finite values of θ the model can be solved by using perturbation theory.
Energy Technology Data Exchange (ETDEWEB)
Maiolino, S
2006-04-15
This work deals both with the behavioral and numerical aspects of the mechanical response of a rock massif to the digging out of a tunnel. The comparison between existing criteria has permitted to stress on some key points, like the dependence of the criterion to the average stress and the extension ratio. A load function, easily identifiable with tests, with regular and convex properties, has been proposed which allows to take into account the shape of the Mohr envelope of the criterion and the extension ratio. Regularized forms of Mohr-Coulomb and Hoek-Brown criteria can thus be achieved. The development of this new criterion has been completed by the proposal of a numerical charts method which greatly speeds up the resolution. For the proposed criterion, the physical problem is equivalent to a purely geometrical problem in polar coordinates in the plan. Numerical charts can thus be built which allow to find immediately the value of plastic deformations and to greatly reduce the processing time. Tunnel calculation methods have been the object of a bibliographic synthesis, specifying the domains and limitations of use of tunnel dimensioning methods used by engineers. The modeling of tunnels excavation has been performed with the stationary algorithm designed for the calculation of systems submitted to mobile loads. This algorithm has been adapted to integrate the new criterion and the numerical charts system. These tools have been validated using a real case study and data supplied by the French national agency of radioactive waste management (ANDRA) in the framework of the MODEX-REP European project (5. Euratom plan). The study of these data has permitted to define a rock wear variable, easily identifiable and allowing to parameterize the damaged rock criterion. (J.S.)
Analytical method for solving radioactive transformations
International Nuclear Information System (INIS)
Vukadin, Z.
1999-01-01
The exact method of solving radioactive transformations is presented. Nonsingular Bateman coefficients, which can be computed using recurrence formulas, greatly reduce computational time and eliminate singularities that often arise in problems involving nuclide transmutations. Depletion function power series expansion enables high accuracy of the performed calculations, specially in a case of a decay constants with closely spaced values. Generality and simplicity of the method make the method useful for many practical applications. (author)
Analytical method for solving radioactive transformations
International Nuclear Information System (INIS)
Vudakin, Z.
1999-01-01
Analytical method for solving radioactive transformations is presented in this paper. High accuracy series expansion of the depletion function and nonsingular Bateman coefficients are used to overcome numerical difficulties when applying well-known Bateman solution of a simple radioactive decay. Generality and simplicity of the method are found to be useful in evaluating nuclide chains with one hundred or more nuclides in the chain. Method enables evaluation of complete chain, without elimination of short-lives nuclides. It is efficient and accurate
Chester, W
1979-01-01
When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How ever, the presentation is more sophisticated than might be considered appropri ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...
Difficulties in Genetics Problem Solving.
Tolman, Richard R.
1982-01-01
Examined problem-solving strategies of 30 high school students as they solved genetics problems. Proposes a new sequence of teaching genetics based on results: meiosis, sex chromosomes, sex determination, sex-linked traits, monohybrid and dihybrid crosses (humans), codominance (humans), and Mendel's pea experiments. (JN)
Problem Solving, Scaffolding and Learning
Lin, Shih-Yin
2012-01-01
Helping students to construct robust understanding of physics concepts and develop good solving skills is a central goal in many physics classrooms. This thesis examine students' problem solving abilities from different perspectives and explores strategies to scaffold students' learning. In studies involving analogical problem solving…
Problem Solving on a Monorail.
Barrow, Lloyd H.; And Others
1994-01-01
This activity was created to address a lack of problem-solving activities for elementary children. A "monorail" activity from the Evening Science Program for K-3 Students and Parents program is presented to illustrate the problem-solving format. Designed for performance at stations by groups of two students. (LZ)
Solving complex fisheries management problems
DEFF Research Database (Denmark)
Petter Johnsen, Jahn; Eliasen, Søren Qvist
2011-01-01
A crucial issue for the new EU common fisheries policy is how to solve the discard problem. Through a study of the institutional set up and the arrangements for solving the discard problem in Denmark, the Faroe Islands, Iceland and Norway, the article identifies the discard problem as related...
Modeling visual problem solving as analogical reasoning.
Lovett, Andrew; Forbus, Kenneth
2017-01-01
We present a computational model of visual problem solving, designed to solve problems from the Raven's Progressive Matrices intelligence test. The model builds on the claim that analogical reasoning lies at the heart of visual problem solving, and intelligence more broadly. Images are compared via structure mapping, aligning the common relational structure in 2 images to identify commonalities and differences. These commonalities or differences can themselves be reified and used as the input for future comparisons. When images fail to align, the model dynamically rerepresents them to facilitate the comparison. In our analysis, we find that the model matches adult human performance on the Standard Progressive Matrices test, and that problems which are difficult for the model are also difficult for people. Furthermore, we show that model operations involving abstraction and rerepresentation are particularly difficult for people, suggesting that these operations may be critical for performing visual problem solving, and reasoning more generally, at the highest level. (PsycINFO Database Record (c) 2016 APA, all rights reserved).
Insightful problem solving in an Asian elephant.
Directory of Open Access Journals (Sweden)
Preston Foerder
Full Text Available The "aha" moment or the sudden arrival of the solution to a problem is a common human experience. Spontaneous problem solving without evident trial and error behavior in humans and other animals has been referred to as insight. Surprisingly, elephants, thought to be highly intelligent, have failed to exhibit insightful problem solving in previous cognitive studies. We tested whether three Asian elephants (Elephas maximus would use sticks or other objects to obtain food items placed out-of-reach and overhead. Without prior trial and error behavior, a 7-year-old male Asian elephant showed spontaneous problem solving by moving a large plastic cube, on which he then stood, to acquire the food. In further testing he showed behavioral flexibility, using this technique to reach other items and retrieving the cube from various locations to use as a tool to acquire food. In the cube's absence, he generalized this tool utilization technique to other objects and, when given smaller objects, stacked them in an attempt to reach the food. The elephant's overall behavior was consistent with the definition of insightful problem solving. Previous failures to demonstrate this ability in elephants may have resulted not from a lack of cognitive ability but from the presentation of tasks requiring trunk-held sticks as potential tools, thereby interfering with the trunk's use as a sensory organ to locate the targeted food.
Problem Solving Model for Science Learning
Alberida, H.; Lufri; Festiyed; Barlian, E.
2018-04-01
This research aims to develop problem solving model for science learning in junior high school. The learning model was developed using the ADDIE model. An analysis phase includes curriculum analysis, analysis of students of SMP Kota Padang, analysis of SMP science teachers, learning analysis, as well as the literature review. The design phase includes product planning a science-learning problem-solving model, which consists of syntax, reaction principle, social system, support system, instructional impact and support. Implementation of problem-solving model in science learning to improve students' science process skills. The development stage consists of three steps: a) designing a prototype, b) performing a formative evaluation and c) a prototype revision. Implementation stage is done through a limited trial. A limited trial was conducted on 24 and 26 August 2015 in Class VII 2 SMPN 12 Padang. The evaluation phase was conducted in the form of experiments at SMPN 1 Padang, SMPN 12 Padang and SMP National Padang. Based on the development research done, the syntax model problem solving for science learning at junior high school consists of the introduction, observation, initial problems, data collection, data organization, data analysis/generalization, and communicating.
Insightful problem solving in an Asian elephant.
Foerder, Preston; Galloway, Marie; Barthel, Tony; Moore, Donald E; Reiss, Diana
2011-01-01
The "aha" moment or the sudden arrival of the solution to a problem is a common human experience. Spontaneous problem solving without evident trial and error behavior in humans and other animals has been referred to as insight. Surprisingly, elephants, thought to be highly intelligent, have failed to exhibit insightful problem solving in previous cognitive studies. We tested whether three Asian elephants (Elephas maximus) would use sticks or other objects to obtain food items placed out-of-reach and overhead. Without prior trial and error behavior, a 7-year-old male Asian elephant showed spontaneous problem solving by moving a large plastic cube, on which he then stood, to acquire the food. In further testing he showed behavioral flexibility, using this technique to reach other items and retrieving the cube from various locations to use as a tool to acquire food. In the cube's absence, he generalized this tool utilization technique to other objects and, when given smaller objects, stacked them in an attempt to reach the food. The elephant's overall behavior was consistent with the definition of insightful problem solving. Previous failures to demonstrate this ability in elephants may have resulted not from a lack of cognitive ability but from the presentation of tasks requiring trunk-held sticks as potential tools, thereby interfering with the trunk's use as a sensory organ to locate the targeted food.
Solving-Problems and Hypermedia Systems
Directory of Open Access Journals (Sweden)
Ricardo LÓPEZ FERNÁNDEZ
2009-06-01
Full Text Available The solving problems like the transfer constitute two nuclei, related, essential in the cognitive investigation and in the mathematical education. No is in and of itself casual that, from the first moment, in the investigations on the application gives the computer science to the teaching the mathematics, cybernetic models were developed that simulated processes problem solving and transfer cotexts (GPS, 1969 and IDEA (Interactive Decision Envisioning Aid, Pea, BrunerCohen, Webster & Mellen, 1987. The present articulates it analyzes, that can contribute to the development in this respect the new technologies hypermedias, give applications that are good to implement processes of learning the heuristic thought and give the capacity of «transfer». From our perspective and from the experience that we have developed in this field, to carry out a function gives analysis and the theories on the problem solving, it requires that we exercise a previous of interpretation the central aspsects over the theories gives the solving problem and transfer starting from the classic theories on the prosecution of the information. In this sense, so much the theory gives the dual memory as the most recent, J. Anderson (1993 based on the mechanisms activation nodes information they allow to establish an interpretation suggester over the mental mechanism that you/they operate in the heuristic processes. On this analysis, the present articulates it develops a theoritical interpretation over the function gives the supports based on technology hypermedia advancing in the definition of a necessary theoretical body, having in it counts that on the other hand the practical experimentation is permanent concluding in the efficiency and effectiveness gives the support hypermedia like mechanism of comunication in the processes heuristic learning.
Energy Technology Data Exchange (ETDEWEB)
Pallister, Sam [University of Bristol, School of Mathematics, Bristol (United Kingdom); Coop, Simon [The Barcelona Institute of Science and Technology, ICFO-Institut de Ciencies Fotoniques, Barcelona (Spain); Formichella, Valerio [Politecnico di Torino, Torino (Italy); Istituto Nazionale di Ricerca Metrologica (INRiM), Torino (Italy); Gampierakis, Nicolas [University of East Anglia, School of Natural Sciences, Norwich (United Kingdom); Notaro, Virginia [Sapienza University of Rome, Department of Mechanical and Aerospace Engineering, Rome (Italy); Knott, Paul [University of Sussex, Department of Physics and Astronomy, Brighton (United Kingdom); Azevedo, Rui [Faculdade de Ciencias da Universidade do Porto, Porto (Portugal); Buchheim, Nikolaus [Max Planck Institute of Quantum Optics, Garching (Germany); De Carvalho, Silvio [University of Applied Sciences Wiener Neustadt, Aerospace Engineering Department, Wiener Neustadt (Austria); Jaervelae, Emilia [Aalto University Metsaehovi Radio Observatory, Kylmaelae (Finland); Aalto University Department of Radio Science and Engineering, Aalto (Finland); Laporte, Matthieu [Universite Paris Diderot, APC (AstroParticule et Cosmologie), Paris (France); Kaikkonen, Jukka-Pekka [Aalto University, Low Temperature Laboratory, Department of Applied Physics, Aalto (Finland); Meshksar, Neda [Leibniz University Hanover, Albert Einstein Institute, Hanover (Germany); Nikkanen, Timo [Aalto University Department of Radio Science and Engineering, Aalto (Finland); Finnish Meteorological Institute, Radar and Space Technology Research Group, Helsinki (Finland); Yttergren, Madeleine [Chalmers University of Technology, Physics and Astronomy, Goeteborg (Sweden)
2017-12-15
In this paper we propose an experiment designed to observe a general-relativistic effect on single photon interference. The experiment consists of a folded Mach-Zehnder interferometer, with the arms distributed between a single Earth orbiter and a ground station. By compensating for other degrees of freedom and the motion of the orbiter, this setup aims to detect the influence of general relativistic time dilation on a spatially superposed single photon. The proposal details a payload to measure the required effect, along with an extensive feasibility analysis given current technological capabilities. (orig.)
Pastor, Dena A.; Dodd, Barbara G.; Chang, Hua-Hua
2002-01-01
Studied the impact of using five different exposure control algorithms in two sizes of item pool calibrated using the generalized partial credit model. Simulation results show that the a-stratified design, in comparison to a no-exposure control condition, could be used to reduce item exposure and overlap and increase pool use, while degrading…
Schulz, Russel E.; And Others
The report, the first of two documents examining the relationship among job requirements, training, and manpower considerations for Army aviation maintenance Personnel, discusses the development of task data gathering techniques and procedures for incorporating this data into training programs for the UH-1 helicopter mechanic sPecialty (MOS…
How to solve mathematical problems
Wickelgren, Wayne A
1995-01-01
Seven problem-solving techniques include inference, classification of action sequences, subgoals, contradiction, working backward, relations between problems, and mathematical representation. Also, problems from mathematics, science, and engineering with complete solutions.
Interactive Problem-Solving Interventions
African Journals Online (AJOL)
Frew Demeke Alemu
concerted efforts of unofficial actors to establish unofficial communication ... Frew Demeke Alemu (LLB, LLM in International Human Rights Law from Lund ..... 24 Tamra Pearson d'Estrée (2009), “Problem-Solving Approaches”, (in The SAGE ...
Energy Technology Data Exchange (ETDEWEB)
Smirnov, A. G., E-mail: smirnov@lpi.ru [I. E. Tamm Theory Department, P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 119991 (Russian Federation)
2015-12-15
We develop a general technique for finding self-adjoint extensions of a symmetric operator that respects a given set of its symmetries. Problems of this type naturally arise when considering two- and three-dimensional Schrödinger operators with singular potentials. The approach is based on constructing a unitary transformation diagonalizing the symmetries and reducing the initial operator to the direct integral of a suitable family of partial operators. We prove that symmetry preserving self-adjoint extensions of the initial operator are in a one-to-one correspondence with measurable families of self-adjoint extensions of partial operators obtained by reduction. The general scheme is applied to the three-dimensional Aharonov-Bohm Hamiltonian describing the electron in the magnetic field of an infinitely thin solenoid. We construct all self-adjoint extensions of this Hamiltonian, invariant under translations along the solenoid and rotations around it, and explicitly find their eigenfunction expansions.
Institute of Scientific and Technical Information of China (English)
燕雪; 张劲文
2015-01-01
在经济全球化推动下，各国、各地区之间的跨境工程合作日益频繁。然而，由于决策主体利益诉求不同、文化价值观差异、信息不对称等因素的影响，导致跨境工程决策主体间冲突越来越显著。如何科学有效地处理跨境工程主体间的决策冲突已引起理论和实践界的关注。结合港珠澳大桥工程多主体间决策冲突处理的实践，系统分析跨境工程前期决策冲突的起因，从内容维和关系维的角度对决策冲突进行分类。在冲突诱因分析及冲突分类的基础上，探索多主体间决策冲突处理机制，为一般跨境工程多主体间决策冲突的处理提供了新的思路和方法。%driven by increasing global economics,the cooperation of cross-border projects between states and districts has become more and more intense. However, due to different profits requirements,different culture and unbalanced information of different decision makers,the conflicts among these decision makers who are responsible for the cross-border projects are rising and becoming a significant factor. How to scientifically and effectively solve the conflicts among decision makers of cross-border projects has drawn attention both theoretically and practically. Based on the practice on dealing with conflicts between decision makers of Hong Kong-Zhuhai-Macao Bridge project,the paper systematically analyzes the cause of conflicts of cross-border projects in the early stage and categorizes such conflicts from the prospective of their contents and inner relationship. Then,the paper explores a conflicts solving system between multiple decision makers and provides new thoughts and methods for solving conflicts between decision makers in common cross-border projects.
International Nuclear Information System (INIS)
Lue Xing; Zhu Hongwu; Yao Zhenzhi; Meng Xianghua; Zhang Cheng; Zhang Chunyi; Tian Bo
2008-01-01
In this paper, the multisoliton solutions in terms of double Wronskian determinant are presented for a generalized variable-coefficient nonlinear Schroedinger equation, which appears in space and laboratory plasmas, arterial mechanics, fluid dynamics, optical communications and so on. By means of the particularly nice properties of Wronskian determinant, the solutions are testified through direct substitution into the bilinear equations. Furthermore, it can be proved that the bilinear Baecklund transformation transforms between (N - 1)- and N-soliton solutions
Tangram solved? Prefrontal cortex activation analysis during geometric problem solving.
Ayaz, Hasan; Shewokis, Patricia A; Izzetoğlu, Meltem; Çakır, Murat P; Onaral, Banu
2012-01-01
Recent neuroimaging studies have implicated prefrontal and parietal cortices for mathematical problem solving. Mental arithmetic tasks have been used extensively to study neural correlates of mathematical reasoning. In the present study we used geometric problem sets (tangram tasks) that require executive planning and visuospatial reasoning without any linguistic representation interference. We used portable optical brain imaging (functional near infrared spectroscopy--fNIR) to monitor hemodynamic changes within anterior prefrontal cortex during tangram tasks. Twelve healthy subjects were asked to solve a series of computerized tangram puzzles and control tasks that required same geometric shape manipulation without problem solving. Total hemoglobin (HbT) concentration changes indicated a significant increase during tangram problem solving in the right hemisphere. Moreover, HbT changes during failed trials (when no solution found) were significantly higher compared to successful trials. These preliminary results suggest that fNIR can be used to assess cortical activation changes induced by geometric problem solving. Since fNIR is safe, wearable and can be used in ecologically valid environments such as classrooms, this neuroimaging tool may help to improve and optimize learning in educational settings.
DEFF Research Database (Denmark)
Sørensen, Bent F.; Jørgensen, K.; Jacobsen, T.K.
2004-01-01
A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratiobetween the two applied moments, the full mode...... glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre bridging, eventually reaching asteady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement....
International Nuclear Information System (INIS)
1985-06-01
The French Rules of Mechanical equipments of Fast Neutron nuclear Reactors (RCC-MR) aims at equipments included in a safety classification. The equipments concerned are those of the nuclear boiler and its auxiliaries: tanks, vessels, internal equipments of the reactor, exchangers, pumps, fittings, pipes, and supports. The present edition of the RCC-MR comprises 12 books presented in the present one in the volume A. The chapter RA 3000 defines the documents to be established in application of the RCC-MR rules. The chapter RA 5000 defines the requirements to take into account to establish and carry out quality Assurance programs according to the RCC-MR rules [fr
Charles, Alexandre; Ballard, Patrick
2016-08-01
The dynamics of mechanical systems with a finite number of degrees of freedom (discrete mechanical systems) is governed by the Lagrange equation which is a second-order differential equation on a Riemannian manifold (the configuration manifold). The handling of perfect (frictionless) unilateral constraints in this framework (that of Lagrange's analytical dynamics) was undertaken by Schatzman and Moreau at the beginning of the 1980s. A mathematically sound and consistent evolution problem was obtained, paving the road for many subsequent theoretical investigations. In this general evolution problem, the only reaction force which is involved is a generalized reaction force, consistently with the virtual power philosophy of Lagrange. Surprisingly, such a general formulation was never derived in the case of frictional unilateral multibody dynamics. Instead, the paradigm of the Coulomb law applying to reaction forces in the real world is generally invoked. So far, this paradigm has only enabled to obtain a consistent evolution problem in only some very few specific examples and to suggest numerical algorithms to produce computational examples (numerical modeling). In particular, it is not clear what is the evolution problem underlying the computational examples. Moreover, some of the few specific cases in which this paradigm enables to write down a precise evolution problem are known to show paradoxes: the Painlevé paradox (indeterminacy) and the Kane paradox (increase in kinetic energy due to friction). In this paper, we follow Lagrange's philosophy and formulate the frictional unilateral multibody dynamics in terms of the generalized reaction force and not in terms of the real-world reaction force. A general evolution problem that governs the dynamics is obtained for the first time. We prove that all the solutions are dissipative; that is, this new formulation is free of Kane paradox. We also prove that some indeterminacy of the Painlevé paradox is fixed in this
Social problem solving ability predicts mental health among undergraduate students.
Ranjbar, Mansour; Bayani, Ali Asghar; Bayani, Ali
2013-11-01
The main objective of this study was predicting student's mental health using social problem solving- ability. In this correlational. descriptive study, 369 (208 female and 161 male) from, Mazandaran University of Medical Science were selected through stratified random sampling method. In order to collect the data, the social problem solving inventory-revised and general health questionnaire were used. Data were analyzed through SPSS-19, Pearson's correlation, t test, and stepwise regression analysis. Data analysis showed significant relationship between social problem solving ability and mental health (P Social problem solving ability was significantly associated with the somatic symptoms, anxiety and insomnia, social dysfunction and severe depression (P social problem solving ability and mental health.
Cincotti, Silvano; Ponta, Linda; Raberto, Marco; Scalas, Enrico
2005-05-01
In this paper, empirical analyses and computational experiments are presented on high-frequency data for a double-auction (book) market. Main objective of the paper is to generalize the order waiting time process in order to properly model such empirical evidences. The empirical study is performed on the best bid and best ask data of 7 U.S. financial markets, for 30-stock time series. In particular, statistical properties of trading waiting times have been analyzed and quality of fits is evaluated by suitable statistical tests, i.e., comparing empirical distributions with theoretical models. Starting from the statistical studies on real data, attention has been focused on the reproducibility of such results in an artificial market. The computational experiments have been performed within the Genoa Artificial Stock Market. In the market model, heterogeneous agents trade one risky asset in exchange for cash. Agents have zero intelligence and issue random limit or market orders depending on their budget constraints. The price is cleared by means of a limit order book. The order generation is modelled with a renewal process. Based on empirical trading estimation, the distribution of waiting times between two consecutive orders is modelled by a mixture of exponential processes. Results show that the empirical waiting-time distribution can be considered as a generalization of a Poisson process. Moreover, the renewal process can approximate real data and implementation on the artificial stocks market can reproduce the trading activity in a realistic way.
Jha, Sanjiv; Brown, Katie; Subramanian, Gopinath
We apply a recent formulation for searching minimum energy reaction path (MERP) and saddle point to atomic systems subjected to an external force. We demonstrate the effect of a loading modality resembling hydrostatic pressure on the trans to cis conformational change of 1,3-butadiene, and the simplest Diels-Alder reaction between ethylene and 1,3-butadiene. The calculated MERP and saddle points on the generalized force modified potential energy surface (G-FMPES) are compared with the corresponding quantities on an unmodified potential energy surface. Our study is performed using electronic structure calculations at the HF/6-31G** level as implemented in the AIMS-MOLPRO code. Our calculations suggest that the added compressive pressure lowers the energy of cis butadiene. The activation energy barrier for the concerted Diels-Alder reaction is found to decrease progressively with increasing compressive pressure.
Planning under uncertainty solving large-scale stochastic linear programs
Energy Technology Data Exchange (ETDEWEB)
Infanger, G. [Stanford Univ., CA (United States). Dept. of Operations Research]|[Technische Univ., Vienna (Austria). Inst. fuer Energiewirtschaft
1992-12-01
For many practical problems, solutions obtained from deterministic models are unsatisfactory because they fail to hedge against certain contingencies that may occur in the future. Stochastic models address this shortcoming, but up to recently seemed to be intractable due to their size. Recent advances both in solution algorithms and in computer technology now allow us to solve important and general classes of practical stochastic problems. We show how large-scale stochastic linear programs can be efficiently solved by combining classical decomposition and Monte Carlo (importance) sampling techniques. We discuss the methodology for solving two-stage stochastic linear programs with recourse, present numerical results of large problems with numerous stochastic parameters, show how to efficiently implement the methodology on a parallel multi-computer and derive the theory for solving a general class of multi-stage problems with dependency of the stochastic parameters within a stage and between different stages.
Collaborative problem solving with a total quality model.
Volden, C M; Monnig, R
1993-01-01
A collaborative problem-solving system committed to the interests of those involved complies with the teachings of the total quality management movement in health care. Deming espoused that any quality system must become an integral part of routine activities. A process that is used consistently in dealing with problems, issues, or conflicts provides a mechanism for accomplishing total quality improvement. The collaborative problem-solving process described here results in quality decision-making. This model incorporates Ishikawa's cause-and-effect (fishbone) diagram, Moore's key causes of conflict, and the steps of the University of North Dakota Conflict Resolution Center's collaborative problem solving model.
Rewarding Multitasking: Negative Effects of an Incentive on Problem Solving under Divided Attention
Wieth, Mareike B.; Burns, Bruce D.
2014-01-01
Research has consistently shown negative effects of multitasking on tasks such as problem solving. This study was designed to investigate the impact of an incentive when solving problems in a multitasking situation. Incentives have generally been shown to increase problem solving (e.g., Wieth & Burns, 2006), however, it is unclear whether an…
Social Problem Solving Ability Predicts Mental Health Among Undergraduate Students
Ranjbar, Mansour; Bayani, Ali Asghar; Bayani, Ali
2013-01-01
Background : The main objective of this study was predicting student′s mental health using social problem solving- ability . Methods : In this correlational- descriptive study, 369 (208 female and 161 male) from, Mazandaran University of Medical Science were selected through stratified random sampling method. In order to collect the data, the social problem solving inventory-revised and general health questionnaire were used. Data were analyzed through SPSS-19, Pearson′s correlation, t tes...
Using a genetic algorithm to solve fluid-flow problems
International Nuclear Information System (INIS)
Pryor, R.J.
1990-01-01
Genetic algorithms are based on the mechanics of the natural selection and natural genetics processes. These algorithms are finding increasing application to a wide variety of engineering optimization and machine learning problems. In this paper, the authors demonstrate the use of a genetic algorithm to solve fluid flow problems. Specifically, the authors use the algorithm to solve the one-dimensional flow equations for a pipe
Directory of Open Access Journals (Sweden)
Kai Yang
2016-01-01
Full Text Available This work investigates a bioinspired microimmune optimization algorithm to solve a general kind of single-objective nonlinear constrained expected value programming without any prior distribution. In the study of algorithm, two lower bound sample estimates of random variables are theoretically developed to estimate the empirical values of individuals. Two adaptive racing sampling schemes are designed to identify those competitive individuals in a given population, by which high-quality individuals can obtain large sampling size. An immune evolutionary mechanism, along with a local search approach, is constructed to evolve the current population. The comparative experiments have showed that the proposed algorithm can effectively solve higher-dimensional benchmark problems and is of potential for further applications.
Gustafsson, Peter; Jonsson, Gunnar; Enghag, Margareta
2015-01-01
The problem-solving process is investigated for five groups of students when solving context-rich problems in an introductory physics course included in an engineering programme. Through transcripts of their conversation, the paths in the problem-solving process have been traced and related to a general problem-solving model. All groups exhibit…
Melo, A; Tavares, I; Sousa, N; Pêgo, J M
2015-08-01
General anesthetics (GA) are well known for the ability to induce a state of reversible loss of consciousness and unresponsiveness to painful stimuli. However, evidence from animal models and clinical studies show that GA exposure may induce behavioral changes beyond acute effects. Most research and concerns are focused on changes in cognition and memory. We will look at effects of GA on behavior that is mediated by the dopaminergic system. Pharmacological resemblance of GA with drugs of abuse, and the complexity and importance of dopaminergic systems in both reward seeking and addictive illnesses make us believe that it deserves an overview about what is already known and what matters to us as healthcare workers and specifically as anesthesiologists. A review of available evidence strongly suggests that there may be a link between the effects of GA on the brain and substance abuse, partly explained by their influence on the dopaminergic system. © 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.
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Eugeniy A. Lukashev
2017-11-01
Full Text Available The occurrence of convective currents and their development from regular forms with the subsequent transition to irregular turbulent currents draw attention to the fact that they are responsible for the efficiency of many technological processes of heat and mass transfer. Such technological processes are basic in the chemical, petrochemical, power, metallurgical and other industries. Convective flows arise in liquids and gases in the gravitational field in the presence of spatial inhomogeneity of the density created by the inhomogeneity of the temperature and the concentration of components arising during, for example, chemical reactions or other causes. With increasing temperature difference, the resting liquid loses its stability, which then leads to the appearance of a convective flow (Rayleigh–Bénard instability. A further increase in the temperature difference leads to an instability of the primary convective flow, and the hydrodynamic crisis leads to a heat transfer crisis. The paper reconstructs the early stage of the Rayleigh–Bénard convective instability considered as a nonequilibrium phase transition with the spinodal decomposition (diffusion separation mechanism.
Energy Technology Data Exchange (ETDEWEB)
Soerensen, B.F.; Joergensen, K.; Oestergaard, R.C. [Risoe National Lab., Materials Dept., Roskilde (Denmark); Jacobsen, T.K. [LM Glasfiber A/S, Lunderskov (Denmark)
2004-03-01
A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratio between the two applied moments, the full mode mixity range from pure mode I to pure mode II can be generated for the same specimen geometry. The specimen allows stable crack growth. In case of large scale crack bridging, mixed mode cohesive laws can be obtained by a J integral based approach. As a preliminary example, fracture of adhesive joints between two glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre cross over bridging, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement. Cohesive stresses were determined by a J integral approach. The deducted shear stress was found to be relative high ({approx} = 20 MPa) in comparison with the normal stress ({approx} = 1 MPa). (au)
Customer-centered problem solving.
Samelson, Q B
1999-11-01
If there is no single best way to attract new customers and retain current customers, there is surely an easy way to lose them: fail to solve the problems that arise in nearly every buyer-supplier relationship, or solve them in an unsatisfactory manner. Yet, all too frequently, companies do just that. Either we deny that a problem exists, we exert all our efforts to pin the blame elsewhere, or we "Band-Aid" the problem instead of fixing it, almost guaranteeing that we will face it again and again.
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
Generalized vector calculus on convex domain
Agrawal, Om P.; Xu, Yufeng
2015-06-01
In this paper, we apply recently proposed generalized integral and differential operators to develop generalized vector calculus and generalized variational calculus for problems defined over a convex domain. In particular, we present some generalization of Green's and Gauss divergence theorems involving some new operators, and apply these theorems to generalized variational calculus. For fractional power kernels, the formulation leads to fractional vector calculus and fractional variational calculus for problems defined over a convex domain. In special cases, when certain parameters take integer values, we obtain formulations for integer order problems. Two examples are presented to demonstrate applications of the generalized variational calculus which utilize the generalized vector calculus developed in the paper. The first example leads to a generalized partial differential equation and the second example leads to a generalized eigenvalue problem, both in two dimensional convex domains. We solve the generalized partial differential equation by using polynomial approximation. A special case of the second example is a generalized isoperimetric problem. We find an approximate solution to this problem. Many physical problems containing integer order integrals and derivatives are defined over arbitrary domains. We speculate that future problems containing fractional and generalized integrals and derivatives in fractional mechanics will be defined over arbitrary domains, and therefore, a general variational calculus incorporating a general vector calculus will be needed for these problems. This research is our first attempt in that direction.
Solving multiconstraint assignment problems using learning automata.
Horn, Geir; Oommen, B John
2010-02-01
This paper considers the NP-hard problem of object assignment with respect to multiple constraints: assigning a set of elements (or objects) into mutually exclusive classes (or groups), where the elements which are "similar" to each other are hopefully located in the same class. The literature reports solutions in which the similarity constraint consists of a single index that is inappropriate for the type of multiconstraint problems considered here and where the constraints could simultaneously be contradictory. This feature, where we permit possibly contradictory constraints, distinguishes this paper from the state of the art. Indeed, we are aware of no learning automata (or other heuristic) solutions which solve this problem in its most general setting. Such a scenario is illustrated with the static mapping problem, which consists of distributing the processes of a parallel application onto a set of computing nodes. This is a classical and yet very important problem within the areas of parallel computing, grid computing, and cloud computing. We have developed four learning-automata (LA)-based algorithms to solve this problem: First, a fixed-structure stochastic automata algorithm is presented, where the processes try to form pairs to go onto the same node. This algorithm solves the problem, although it requires some centralized coordination. As it is desirable to avoid centralized control, we subsequently present three different variable-structure stochastic automata (VSSA) algorithms, which have superior partitioning properties in certain settings, although they forfeit some of the scalability features of the fixed-structure algorithm. All three VSSA algorithms model the processes as automata having first the hosting nodes as possible actions; second, the processes as possible actions; and, third, attempting to estimate the process communication digraph prior to probabilistically mapping the processes. This paper, which, we believe, comprehensively reports the
Multiscale empirical interpolation for solving nonlinear PDEs
Calo, Victor M.
2014-12-01
In this paper, we propose a multiscale empirical interpolation method for solving nonlinear multiscale partial differential equations. The proposed method combines empirical interpolation techniques and local multiscale methods, such as the Generalized Multiscale Finite Element Method (GMsFEM). To solve nonlinear equations, the GMsFEM is used to represent the solution on a coarse grid with multiscale basis functions computed offline. Computing the GMsFEM solution involves calculating the system residuals and Jacobians on the fine grid. We use empirical interpolation concepts to evaluate these residuals and Jacobians of the multiscale system with a computational cost which is proportional to the size of the coarse-scale problem rather than the fully-resolved fine scale one. The empirical interpolation method uses basis functions which are built by sampling the nonlinear function we want to approximate a limited number of times. The coefficients needed for this approximation are computed in the offline stage by inverting an inexpensive linear system. The proposed multiscale empirical interpolation techniques: (1) divide computing the nonlinear function into coarse regions; (2) evaluate contributions of nonlinear functions in each coarse region taking advantage of a reduced-order representation of the solution; and (3) introduce multiscale proper-orthogonal-decomposition techniques to find appropriate interpolation vectors. We demonstrate the effectiveness of the proposed methods on several nonlinear multiscale PDEs that are solved with Newton\\'s methods and fully-implicit time marching schemes. Our numerical results show that the proposed methods provide a robust framework for solving nonlinear multiscale PDEs on a coarse grid with bounded error and significant computational cost reduction.
Tong, Guoxiu; Du, Fangfang; Xiang, Lingjing; Liu, Fangting; Mao, Lulu; Guan, Jianguo
2013-12-01
This paper describes a green versatile glucose-engineered precipitation-sintering process that allows for the selective and mass preparation of spongy porous ferrite (M = Fe, Zn, Co, Ni, Mn, etc.) micro-polyhedra with tunable morphology, texture, and composition. Some kinetic factors, such as the molar ratio of glucose to metal nitrates, reaction temperature, sintering temperature and time, and type of metal nitrates, can be expediently employed to modulate their aspect ratio, shape, size, composition, and textural properties. In this protocol, glucose functions as a reductant, protecting agent, structure-directing agent, and a sacrificial template to guide the assembly of sheet-like nuclei into polyhedral precursors and the formation of spongy porous structures. Owing to larger EM parameters, multiresonant behavior, and dissipative current, spongy porous Fe3O4 polyhedra exhibited enhanced microwave-absorbing properties. This endows them with important potential applications in magnetic devices, catalysis, sorption, photoluminescence, electromagnetic wave absorbing materials, anode materials, and so on. Meanwhile, this general approach can be extended to synthesize other porous sponges with regular geometric configuration because it is simple, inexpensive, environmentally benign, and suitable for extensive production.This paper describes a green versatile glucose-engineered precipitation-sintering process that allows for the selective and mass preparation of spongy porous ferrite (M = Fe, Zn, Co, Ni, Mn, etc.) micro-polyhedra with tunable morphology, texture, and composition. Some kinetic factors, such as the molar ratio of glucose to metal nitrates, reaction temperature, sintering temperature and time, and type of metal nitrates, can be expediently employed to modulate their aspect ratio, shape, size, composition, and textural properties. In this protocol, glucose functions as a reductant, protecting agent, structure-directing agent, and a sacrificial template to
Directory of Open Access Journals (Sweden)
Libor Velíšek
Full Text Available Idiopathic generalized epilepsy (IGE syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mice, a null mutation at the homologous Brd2 locus results in embryonic lethality while heterozygous Brd2+/- mice are viable and overtly normal. However, using the flurothyl model, we now show, that compared to the Brd2+/+ littermates, Brd2+/- males have a decreased clonic, and females a decreased tonic-clonic, seizure threshold. Additionally, long-term EEG/video recordings captured spontaneous seizures in three out of five recorded Brd2+/- female mice. Anatomical analysis of specific regions of the brain further revealed significant differences in Brd2+/- vs +/+ mice. Specifically, there were decreases in the numbers of GABAergic (parvalbumin- or GAD67-immunopositive neurons along the basal ganglia pathway, i.e., in the neocortex and striatum of Brd2+/- mice, compared to Brd2+/+ mice. There were also fewer GABAergic neurons in the substantia nigra reticulata (SNR, yet there was a minor, possibly compensatory increase in the GABA producing enzyme GAD67 in these SNR cells. Further, GAD67 expression in the superior colliculus and ventral medial thalamic nucleus, the main SNR outputs, was significantly decreased in Brd2+/- mice, further supporting GABA downregulation. Our data show that the non-channel-encoding, developmentally critical Brd2 gene is associated with i sex-specific increases in seizure susceptibility, ii the development of spontaneous seizures, and iii seizure-related anatomical changes in the GABA system, supporting BRD2's involvement in human IGE.
Osman, Frederick; Ghahramani, Nader; Hora, Heinrich
2005-10-01
The studies of laser ablation have lead to a new theory of nuclei, endothermic nuclei generation, and quark-gluon plasmas. The surface of ablated plasma expanding into vacuum after high power laser irradiation of targets contains an electric double layer having the thickness of the Debye length. This led to the discovery of surface tension in plasmas, and led to the internal dynamic electric fields in all inhomogeneous plasmas. The surface tension causes stabilization by short length surface wave smoothing the expanding plasma plume and to stabilization against the Rayleigh Taylor instability. Generalizing this to the degenerate electrons in a metal with the Fermi energy instead of the temperature resulted in the first quantum theory of surface tension of metals in agreement with measurements. Taking the Fermi energy in the Debye length for nucleons results in a theory of nuclei with stable confinement of protons and neutrons just at the well-known nuclear density, and the Debye lengths equal to the Hofstadter decay of the nuclear surface. Increasing the nuclear density by a factor of 10 leads to a change of the Fermi energy into its relativistic branch where no surface energy is possible and the particle mass is not defined, permitting the quark gluon plasma. Expansion of this higher density at the big bang or in super-nova results in nucleation and element generation. The Boltzmann equilibrium permits the synthesis of nuclei even in the endothermic range, however with the limit to about uranium. A relation for the magic numbers leads to a quark structure of nuclear shells that can be understood as a duality property of nuclei with respect to nucleons and quarks
Fernandez, Renae C; Peters, Susan; Carey, Renee N; Davies, Michael J; Fritschi, Lin
2014-10-01
To develop a job-exposure matrix (JEM) that estimates exposure to eight variables representing different aspects of shiftwork among female workers. Occupational history and shiftwork exposure data were obtained from a population-based breast cancer case-control study. Exposure to light at night, phase shift, sleep disturbances, poor diet, lack of physical activity, lack of vitamin D, and graveyard and early morning shifts, was calculated by occupational code. Three threshold values based on the frequency of exposure were considered (10%, 30% and 50%) for use as cut-offs in determining exposure for each occupational code. JEM-based exposure classification was compared with that from the OccIDEAS application (job-specific questionnaires and assessment by rules) by assessing the effect on the OR for phase shift and breast cancer. Using data from the Australian Workplace Exposure Study, the specificity and sensitivity of the threshold values were calculated for each exposure variable. 127 of 413 occupational codes involved exposure to one or more shiftwork variables. Occupations with the highest probability of exposure shiftwork included nurses and midwives. Using the 30% threshold, the OR for the association between phase shift exposure and breast cancer was decreased and no longer statistically significant (OR=1.14, 95% CI 0.92 to 1.42). The 30% cut-off point demonstrated best specificity and sensitivity, although results varied between exposure variables. This JEM provides a set of indicators reflecting biologically plausible mechanisms for the potential impact of shiftwork on health and may provide an alternative method of exposure assessment in the absence of detailed job history and exposure data. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
The software package for solving problems of mathematical modeling of isothermal curing process
Directory of Open Access Journals (Sweden)
S. G. Tikhomirov
2016-01-01
Full Text Available Summary. On the basis of the general laws of sulfur vulcanization diene rubbers the principles of the effective cross-linking using a multi-component agents was discussed. It is noted that the description of the mechanism of action of the complex cross-linking systems are complicated by the diversity of interactions of components and the influence of each of them on the curing kinetics, leading to a variety technological complications of real technology and affects on the quality and technical and economic indicators of the production of rubber goods. Based on the known theoretical approaches the system analysis of isothermal curing process was performed. It included the integration of different techniques and methods into a single set of. During the analysis of the kinetics of vulcanization it was found that the formation of the spatial grid parameters vulcanizates depend on many factors, to assess which requires special mathematical and algorithmic support. As a result of the stratification of the object were identified the following major subsystems. A software package for solving direct and inverse kinetic problems isothermal curing process was developed. Information support “Isothermal vulcanization” is a set of applications of mathematical modeling of isothermal curing. It is intended for direct and inverse kinetic problems. When solving the problem of clarifying the general scheme of chemical transformations used universal mechanism including secondary chemical reactions. Functional minimization algorithm with constraints on the unknown parameters was used for solving the inverse kinetic problem. Shows a flowchart of the program. An example of solving the inverse kinetic problem with the program was introduced. Dataware was implemented in the programming language C ++. Universal dependence to determine the initial concentration of the curing agent was applied . It allowing the use of a model with different properties of multicomponent
Directory of Open Access Journals (Sweden)
Denollet Johan
2010-01-01
Full Text Available Abstract Background The objective was to review all available literature concerning Type D (distressed personality among the general population and to discuss its implications for research on health status, disease-promoting mechanisms and work-related problems in non-clinical populations. Methods A computerized search of the literature was performed independently and in duplicate by both investigators on December 21st, 2009. Published research reports were included if they studied Type D personality among the general population. Nineteen articles were selected and they were subjected to an 11-item standardised quality checklist by both investigators. Results The methodological quality of the selected studies was adequate to high. The studies included in this review showed that the presence of Type D characteristics had a negative impact on mental health status (more symptoms of depression, anxiety, post-traumatic stress disorder, mental distress, passive coping, and less social support and physical health status (more somatic complaints, lower health status, more influenza-like illness reporting. Other studies reported on behavioral and biological mechanisms of disease in apparently healthy individuals with a Type D personality. Finally, some studies also showed a negative effect of Type D personality on work-related problems (higher absence-leave, higher levels of vital exhaustion and burnout, and more work-related stress. Conclusions Type D personality is a vulnerability factor for general psychological distress that affects mental and physical health status and is associated with disease-promoting mechanisms and work-related problems in apparently healthy individuals.
International Nuclear Information System (INIS)
Hartmann, B.; Leng, M.; Ramstein, J.
1986-01-01
The deuteration rates of the poly(dA-dT).poly(dA-dT) amino and imino protons have been measured with stopped-flow spectrophotometry as a function of general and specific base catalyst concentration. Two proton exchange classes are found with time constants differing by a factor of 10 (4 and 0.4 s-1). The slower class represents the exchange of the adenine amino protons whereas the proton of the faster class has been assigned to the thymine imino proton. The exchange rates of these two classes of protons are independent of general and specific base catalyst concentration. This very characteristic behavior demonstrates that in our experimental conditions the exchange rates of the imino and amino protons in poly(dA-dT).poly(dA-dT) are limited by two different conformational fluctuations. We present a three-state exchange mechanism accounting for our experimental results
Funke, Joachim
2013-01-01
This paper presents a bibliography of 263 references related to human problem solving, arranged by subject matter. The references were taken from PsycInfo and Academic Premier data-base. Journal papers, book chapters, and dissertations are included. The topics include human development, education, neuroscience, and research in applied settings. It…
Solved problems in classical electromagnetism
Franklin, Jerrold
2018-01-01
This original Dover publication is the companion to a new edition of the author's Classical Electromagnetism: Second Edition. The latter volume will feature only basic answers; this book will contain some problems from the reissue as well as many other new ones. All feature complete, worked-out solutions and form a valuable source of problem-solving material for students.
Error Patterns in Problem Solving.
Babbitt, Beatrice C.
Although many common problem-solving errors within the realm of school mathematics have been previously identified, a compilation of such errors is not readily available within learning disabilities textbooks, mathematics education texts, or teacher's manuals for school mathematics texts. Using data on error frequencies drawn from both the Fourth…
Quantitative Reasoning in Problem Solving
Ramful, Ajay; Ho, Siew Yin
2015-01-01
In this article, Ajay Ramful and Siew Yin Ho explain the meaning of quantitative reasoning, describing how it is used in the to solve mathematical problems. They also describe a diagrammatic approach to represent relationships among quantities and provide examples of problems and their solutions.
Students' Problem Solving and Justification
Glass, Barbara; Maher, Carolyn A.
2004-01-01
This paper reports on methods of students' justifications of their solution to a problem in the area of combinatorics. From the analysis of the problem solving of 150 students in a variety of settings from high-school to graduate study, four major forms of reasoning evolved: (1) Justification by Cases, (2) Inductive Argument, (3) Elimination…
International Nuclear Information System (INIS)
Wei, Guang-Mei
2006-01-01
Generalized two-dimensional variable-coefficient Burgers model is of current value in fluid mechanics, acoustics and cosmic-ray astrophysics. In this paper, Painleve analysis leads to the constraints on the variable coefficients for such a model to pass the Painleve test and to an auto-Baecklund transformation. Moreover, four transformations from this model are constructed, to the standard two-dimensional and one-dimensional Burgers models with the relevant constraints on the variable coefficients via symbolic computation. By virtue of the given transformations the properties and solutions of this model can be obtained from those of the standard two-dimensional and one-dimensional ones
Problem solving skills for schizophrenia.
Xia, J; Li, Chunbo
2007-04-18
The severe and long-lasting symptoms of schizophrenia are often the cause of severe disability. Environmental stress such as life events and the practical problems people face in their daily can worsen the symptoms of schizophrenia. Deficits in problem solving skills in people with schizophrenia affect their independent and interpersonal functioning and impair their quality of life. As a result, therapies such as problem solving therapy have been developed to improve problem solving skills for people with schizophrenia. To review the effectiveness of problem solving therapy compared with other comparable therapies or routine care for those with schizophrenia. We searched the Cochrane Schizophrenia Group's Register (September 2006), which is based on regular searches of BIOSIS, CENTRAL, CINAHL, EMBASE, MEDLINE and PsycINFO. We inspected references of all identified studies for further trials. We included all clinical randomised trials comparing problem solving therapy with other comparable therapies or routine care. We extracted data independently. For homogenous dichotomous data we calculated random effects, relative risk (RR), 95% confidence intervals (CI) and, where appropriate, numbers needed to treat (NNT) on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD) using a random effects statistical model. We included only three small trials (n=52) that evaluated problem solving versus routine care, coping skills training or non-specific interaction. Inadequate reporting of data rendered many outcomes unusable. We were unable to undertake meta-analysis. Overall results were limited and inconclusive with no significant differences between treatment groups for hospital admission, mental state, behaviour, social skills or leaving the study early. No data were presented for global state, quality of life or satisfaction. We found insufficient evidence to confirm or refute the benefits of problem solving therapy as an additional
Rice, Frances; Rawal, Adhip; Riglin, Lucy; Lewis, Gemma; Lewis, Glyn; Dunsmuir, Sandra
2015-11-01
Effective methods to prevent adolescent depressive symptoms could reduce suffering and burden across the lifespan. However, psychological interventions delivered to adolescents show efficacy only in symptomatic or high-risk youth. Targeting causal risk factors and assessing mechanistic change can help devise efficacious universal or classroom based prevention programs. A non-randomized longitudinal design was used to compare three classroom-based prevention programs for adolescent depression (Behavioral Activation with Reward Processing, "Thinking about Reward in Young People" (TRY); Cognitive Behavioral Therapy (CBT) and Mindfulness Based Cognitive Therapy (MBCT)), and determine cognitive mechanisms of change in these programs. Cognitive mechanisms examined were reward-seeking, negative self-beliefs (assessed with behavioral tasks) and over-general autobiographical memory. 256 healthy adolescents aged 13-14 participated with 236 (92%) and 227 (89%) completing the pre- and post-assessments. TRY was the only intervention associated with a reduction in depressive symptoms at follow-up. Reward-seeking increased following TRY. In the other programs there were non-significant changes in cognitive mechanisms, with more reflective negative self-beliefs in CBT and fewer over-general autobiographical memories in MBCT In the TRY program, which focused on increasing sensitivity to rewarding activities, reward seeking increased and this was associated with decreased depressive symptoms. Due to the infeasibility of a cluster randomized controlled trial, a non-randomized design was used. Increased reward-seeking was associated with decreased depressive symptoms and may be a mechanism of depressive symptom change in the intervention with a focus on enhancing sensitivity and awareness of reward. This study provides preliminary evidence to suggest that incorporating activities to enhance reward sensitivity may be fruitful in randomized controlled trials of universal prevention
Genetics problem solving and worldview
Dale, Esther
The research goal was to determine whether worldview relates to traditional and real-world genetics problem solving. Traditionally, scientific literacy emphasized content knowledge alone because it was sufficient to solve traditional problems. The contemporary definition of scientific literacy is, "The knowledge and understanding of scientific concepts and processes required for personal decision-making, participation in civic and cultural affairs and economic productivity" (NRC, 1996). An expanded definition of scientific literacy is needed to solve socioscientific issues (SSI), complex social issues with conceptual, procedural, or technological associations with science. Teaching content knowledge alone assumes that students will find the scientific explanation of a phenomenon to be superior to a non-science explanation. Formal science and everyday ways of thinking about science are two different cultures (Palmer, 1999). Students address this rift with cognitive apartheid, the boxing away of science knowledge from other types of knowledge (Jedege & Aikenhead, 1999). By addressing worldview, cognitive apartheid may decrease and scientific literacy may increase. Introductory biology students at the University of Minnesota during fall semester 2005 completed a written questionnaire-including a genetics content-knowledge test, four genetic dilemmas, the Worldview Assessment Instrument (WAI) and some items about demographics and religiosity. Six students responded to the interview protocol. Based on statistical analysis and interview data, this study concluded the following: (1) Worldview, in the form of metaphysics, relates to solving traditional genetic dilemmas. (2) Worldview, in the form of agency, relates to solving traditional genetics problems. (3) Thus, worldview must be addressed in curriculum, instruction, and assessment.
International Nuclear Information System (INIS)
Papoyan, V.V.
1989-01-01
A Kerr generalized solution for a stationary axially-symmetric gravitational field of rotating self-gravitational objects is given. For solving the problem Einstein equations and their combinations are used. The particular cases: internal and external Schwarzschild solutions are considered. The external solution of the stationary problem is a Kerr solution generalization. 3 refs
Understanding catastrophizing from a misdirected problem-solving perspective.
Flink, Ida K; Boersma, Katja; MacDonald, Shane; Linton, Steven J
2012-05-01
The aim is to explore pain catastrophizing from a problem-solving perspective. The links between catastrophizing, problem framing, and problem-solving behaviour are examined through two possible models of mediation as inferred by two contemporary and complementary theoretical models, the misdirected problem solving model (Eccleston & Crombez, 2007) and the fear-anxiety-avoidance model (Asmundson, Norton, & Vlaeyen, 2004). In this prospective study, a general population sample (n= 173) with perceived problems with spinal pain filled out questionnaires twice; catastrophizing and problem framing were assessed on the first occasion and health care seeking (as a proxy for medically oriented problem solving) was assessed 7 months later. Two different approaches were used to explore whether the data supported any of the proposed models of mediation. First, multiple regressions were used according to traditional recommendations for mediation analyses. Second, a bootstrapping method (n= 1000 bootstrap resamples) was used to explore the significance of the indirect effects in both possible models of mediation. The results verified the concepts included in the misdirected problem solving model. However, the direction of the relations was more in line with the fear-anxiety-avoidance model. More specifically, the mediation analyses provided support for viewing catastrophizing as a mediator of the relation between biomedical problem framing and medically oriented problem-solving behaviour. These findings provide support for viewing catastrophizing from a problem-solving perspective and imply a need to examine and address problem framing and catastrophizing in back pain patients. ©2011 The British Psychological Society.
Internet computer coaches for introductory physics problem solving
Xu Ryan, Qing
The ability to solve problems in a variety of contexts is becoming increasingly important in our rapidly changing technological society. Problem-solving is a complex process that is important for everyday life and crucial for learning physics. Although there is a great deal of effort to improve student problem solving skills throughout the educational system, national studies have shown that the majority of students emerge from such courses having made little progress toward developing good problem-solving skills. The Physics Education Research Group at the University of Minnesota has been developing Internet computer coaches to help students become more expert-like problem solvers. During the Fall 2011 and Spring 2013 semesters, the coaches were introduced into large sections (200+ students) of the calculus based introductory mechanics course at the University of Minnesota. This dissertation, will address the research background of the project, including the pedagogical design of the coaches and the assessment of problem solving. The methodological framework of conducting experiments will be explained. The data collected from the large-scale experimental studies will be discussed from the following aspects: the usage and usability of these coaches; the usefulness perceived by students; and the usefulness measured by final exam and problem solving rubric. It will also address the implications drawn from this study, including using this data to direct future coach design and difficulties in conducting authentic assessment of problem-solving.
CSIR Research Space (South Africa)
Motara, YM
2017-09-01
Full Text Available the intersection between the SHA-1 preimage problem, the encoding of that problem for SAT-solving, and SAT-solving. The results demonstrate that SAT-solving is not yet a viable approach to take to solve the preimage problem, and also indicate that some...
Assessing Algebraic Solving Ability: A Theoretical Framework
Lian, Lim Hooi; Yew, Wun Thiam
2012-01-01
Algebraic solving ability had been discussed by many educators and researchers. There exists no definite definition for algebraic solving ability as it can be viewed from different perspectives. In this paper, the nature of algebraic solving ability in terms of algebraic processes that demonstrate the ability in solving algebraic problem is…
Zhang, Yin; Chu, Samuel K. W.
2016-01-01
In recent years, a number of models concerning problem solving systems have been put forward. However, many of them stress on technology and neglect the research of problem solving itself, especially the learning mechanism related to problem solving. In this paper, we analyze the learning mechanism of problem solving, and propose that when…
Methods of solving nonstandard problems
Grigorieva, Ellina
2015-01-01
This book, written by an accomplished female mathematician, is the second to explore nonstandard mathematical problems – those that are not directly solved by standard mathematical methods but instead rely on insight and the synthesis of a variety of mathematical ideas. It promotes mental activity as well as greater mathematical skills, and is an ideal resource for successful preparation for the mathematics Olympiad. Numerous strategies and techniques are presented that can be used to solve intriguing and challenging problems of the type often found in competitions. The author uses a friendly, non-intimidating approach to emphasize connections between different fields of mathematics and often proposes several different ways to attack the same problem. Topics covered include functions and their properties, polynomials, trigonometric and transcendental equations and inequalities, optimization, differential equations, nonlinear systems, and word problems. Over 360 problems are included with hints, ...
Confluent-Functional solving systems
Directory of Open Access Journals (Sweden)
V.N. Koval
2001-08-01
Full Text Available The paper proposes a statistical knowledge-acquision approach. The solving systems are considered, which are able to find unknown structural dependences between situational and transforming variables on the basis of statistically analyzed input information. Situational variables describe features, states and relations between environment objects. Transforming variables describe transforming influences, exerted by a goal-oriented system onto an environment. Unknown environment rules are simulated by a structural equations system, associating situational and transforming variables.
Social problem solving ability predicts mental health among undergraduate students
Directory of Open Access Journals (Sweden)
Mansour Ranjbar
2013-01-01
Methods : In this correlational- descriptive study, 369 (208 female and 161 male from, Mazandaran University of Medical Science were selected through stratified random sampling method. In order to collect the data, the social problem solving inventory-revised and general health questionnaire were used. Data were analyzed through SPSS-19, Pearson′s correlation, t test, and stepwise regression analysis. Results : Data analysis showed significant relationship between social problem solving ability and mental health (P < 0.01. Social problem solving ability was significantly associated with the somatic symptoms, anxiety and insomnia, social dysfunction and severe depression (P < 0.01. Conclusions: The results of our study demonstrated that there is a significant correlation between social problem solving ability and mental health.
Problem solving in foundation engineering using foundationPro
Yamin, Mohammad
2016-01-01
This book is at once a supplement to traditional foundation engineering textbooks and an independent problem-solving learning tool. The book is written primarily for university students majoring in civil or construction engineering taking foundation analysis and design courses to encourage them to solve design problems. Its main aim is to stimulate problem solving capability and foster self-directed learning. It also explains the use of the foundationPro software, available at no cost, and includes a set of foundation engineering applications. Taking a unique approach, Dr. Yamin summarizes the general step-by-step procedure to solve various foundation engineering problems, illustrates traditional applications of these steps with longhand solutions, and presents the foundationPro solutions. The special structure of the book allows it to be used in undergraduate and graduate foundation design and analysis courses in civil and construction engineering. The book stands as valuable resource for students, faculty, ...
On a generalized oscillator system: interbasis expansions
Energy Technology Data Exchange (ETDEWEB)
Kibler, M [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Mardoyan, L G; Pogosyan, G S [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics
1997-12-31
This article deals with a nonrelativistic quantum mechanical study of a dynamical system which generalizes the isotropic harmonic oscillator system in three dimensions. The Schroedinger equation for this generalized oscillator system is separable in spherical, cylindrical, and spheroidal (prolate and oblate) coordinates. The quantum mechanical spectrum of this system is worked out in some details. The problem of interbasis expansions of the wave functions is completely solved. The coefficients for the expansion of the cylindrical basis in terms of the spherical basis, and vice-versa, are found to be analytic continuations (to real values of their arguments) of Clebsch-Gordan coefficients for the group SU(2). The interbasis expansion coefficients for the prolate and oblate spheroidal bases in terms of the spherical or the cylindrical bases are shown to satisfy three-term recursion relations. Finally, a connection between the generalized oscillator system (projected on the z-line) and the Morse system (in one dimension) are discussed. 41 refs.,.
On a generalized oscillator system: interbasis expansions
International Nuclear Information System (INIS)
Kibler, M.; Mardoyan, L.G.; Pogosyan, G.S.
1996-01-01
This article deals with a nonrelativistic quantum mechanical study of a dynamical system which generalizes the isotropic harmonic oscillator system in three dimensions. The Schroedinger equation for this generalized oscillator system is separable in spherical, cylindrical, and spheroidal (prolate and oblate) coordinates. The quantum mechanical spectrum of this system is worked out in some details. The problem of interbasis expansions of the wave functions is completely solved. The coefficients for the expansion of the cylindrical basis in terms of the spherical basis, and vice-versa, are found to be analytic continuations (to real values of their arguments) of Clebsch-Gordan coefficients for the group SU(2). The interbasis expansion coefficients for the prolate and oblate spheroidal bases in terms of the spherical or the cylindrical bases are shown to satisfy three-term recursion relations. Finally, a connection between the generalized oscillator system (projected on the z-line) and the Morse system (in one dimension) are discussed. 41 refs.,
Divide et impera: subgoaling reduces the complexity of probabilistic inference and problem solving.
Maisto, Domenico; Donnarumma, Francesco; Pezzulo, Giovanni
2015-03-06
It has long been recognized that humans (and possibly other animals) usually break problems down into smaller and more manageable problems using subgoals. Despite a general consensus that subgoaling helps problem solving, it is still unclear what the mechanisms guiding online subgoal selection are during the solution of novel problems for which predefined solutions are not available. Under which conditions does subgoaling lead to optimal behaviour? When is subgoaling better than solving a problem from start to finish? Which is the best number and sequence of subgoals to solve a given problem? How are these subgoals selected during online inference? Here, we present a computational account of subgoaling in problem solving. Following Occam's razor, we propose that good subgoals are those that permit planning solutions and controlling behaviour using less information resources, thus yielding parsimony in inference and control. We implement this principle using approximate probabilistic inference: subgoals are selected using a sampling method that considers the descriptive complexity of the resulting sub-problems. We validate the proposed method using a standard reinforcement learning benchmark (four-rooms scenario) and show that the proposed method requires less inferential steps and permits selecting more compact control programs compared to an equivalent procedure without subgoaling. Furthermore, we show that the proposed method offers a mechanistic explanation of the neuronal dynamics found in the prefrontal cortex of monkeys that solve planning problems. Our computational framework provides a novel integrative perspective on subgoaling and its adaptive advantages for planning, control and learning, such as for example lowering cognitive effort and working memory load. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Nuclear and hadronic reaction mechanisms producing spin asymmetry
Indian Academy of Sciences (India)
We brieﬂy review concept of the quark recombination (QRC) model and a general success of the model. To solve the existing problem, so called anomalous spin observables, in the high energy hyperon spin phenomena, we propose a mechanism; the primarily produced quarks, which are predominantly and quarks, ...
Wang, Weiwei; Dang, Jingshuang; Zhao, Xiang
2011-08-28
Density functional theory (DFT) methods have been applied to study C(32) fullerenes built from four-, five-, and six-membered rings. The relative energies of pure C(32) fullerenes have been evaluated to locate three most stable structures, 32:D(4d) with two squares, 1:D(3) without square and 5:C(s) with one square. Structural analysis reveals that there is a rearrangement pathway between the lowest energy classical isomer 1:D(3) and the lowest energy non-classical isomer 32:D(4d), and 5:C(s) behaves just as an intermediate between them. The kinetic processes of generalized Stone-Wales transformation (GSWT) with four-membered rings have been explored and two distinct reaction mechanisms are determined by all the transition states and intrinsic reaction coordinates with PBE1PBE/6-31G(d) approach for the first time. One mechanism is the concerted reaction with a rotating dimer closed to the cage surface and another is the stepwise reaction with a carbene-like sp(3) structure, whereas the latter is sorted into two paths based on four-membered ring vanishing before or after the formation of the carbene-like structure. It is indicated that there is no absolute preference for any mechanism, which depends on the adaptability of different reactants on the diverse mechanisms. Furthermore, it's found that the interconversion process with the participation of squares is more reactive than the rearrangement between C(60)_I(h) and C(60)_C(2v), implying some potential importance of non-classical small fullerenes in the fullerene isomerization.
Generalized Continuum: from Voigt to the Modeling of Quasi-Brittle Materials
Directory of Open Access Journals (Sweden)
Jamile Salim Fuina
2010-12-01
Full Text Available This article discusses the use of the generalized continuum theories to incorporate the effects of the microstructure in the nonlinear finite element analysis of quasi-brittle materials and, thus, to solve mesh dependency problems. A description of the problem called numerically induced strain localization, often found in Finite Element Method material non-linear analysis, is presented. A brief historic about the Generalized Continuum Mechanics based models is presented, since the initial work of Voigt (1887 until the more recent studies. By analyzing these models, it is observed that the Cosserat and microstretch approaches are particular cases of a general formulation that describes the micromorphic continuum. After reporting attempts to incorporate the material microstructure in Classical Continuum Mechanics based models, the article shows the recent tendency of doing it according to assumptions of the Generalized Continuum Mechanics. Finally, it presents numerical results which enable to characterize this tendency as a promising way to solve the problem.
Comprehension and computation in Bayesian problem solving
Directory of Open Access Journals (Sweden)
Eric D. Johnson
2015-07-01
Full Text Available Humans have long been characterized as poor probabilistic reasoners when presented with explicit numerical information. Bayesian word problems provide a well-known example of this, where even highly educated and cognitively skilled individuals fail to adhere to mathematical norms. It is widely agreed that natural frequencies can facilitate Bayesian reasoning relative to normalized formats (e.g. probabilities, percentages, both by clarifying logical set-subset relations and by simplifying numerical calculations. Nevertheless, between-study performance on transparent Bayesian problems varies widely, and generally remains rather unimpressive. We suggest there has been an over-focus on this representational facilitator (i.e. transparent problem structures at the expense of the specific logical and numerical processing requirements and the corresponding individual abilities and skills necessary for providing Bayesian-like output given specific verbal and numerical input. We further suggest that understanding this task-individual pair could benefit from considerations from the literature on mathematical cognition, which emphasizes text comprehension and problem solving, along with contributions of online executive working memory, metacognitive regulation, and relevant stored knowledge and skills. We conclude by offering avenues for future research aimed at identifying the stages in problem solving at which correct versus incorrect reasoners depart, and how individual difference might influence this time point.
International Nuclear Information System (INIS)
Granger, R.A.
1985-01-01
This text offers the most comprehensive approach available to fluid mechanics. The author takes great care to insure a physical understanding of concepts grounded in applied mathematics. The presentation of theory is followed by engineering applications, helping students develop problem-solving skills from the perspective of a professional engineer. Extensive use of detailed examples reinforces the understanding of theoretical concepts
A Flipped Pedagogy for Expert Problem Solving
Pritchard, David
The internet provides free learning opportunities for declarative (Wikipedia, YouTube) and procedural (Kahn Academy, MOOCs) knowledge, challenging colleges to provide learning at a higher cognitive level. Our ``Modeling Applied to Problem Solving'' pedagogy for Newtonian Mechanics imparts strategic knowledge - how to systematically determine which concepts to apply and why. Declarative and procedural knowledge is learned online before class via an e-text, checkpoint questions, and homework on edX.org (see http://relate.mit.edu/physicscourse); it is organized into five Core Models. Instructors then coach students on simple ``touchstone problems'', novel exercises, and multi-concept problems - meanwhile exercising three of the four C's: communication, collaboration, critical thinking and problem solving. Students showed 1.2 standard deviations improvement on the MIT final exam after three weeks instruction, a significant positive shift in 7 of the 9 categories in the CLASS, and their grades improved by 0.5 standard deviation in their following physics course (Electricity and Magnetism).
Gross, Dietmar; Schröder, Jörg; Wall, Wolfgang A; Rajapakse, Nimal
Statics is the first volume of a three-volume textbook on Engineering Mechanics. The authors, using a time-honoured straightforward and flexible approach, present the basic concepts and principles of mechanics in the clearest and simplest form possible to advanced undergraduate engineering students of various disciplines and different educational backgrounds. An important objective of this book is to develop problem solving skills in a systematic manner. Another aim of this volume is to provide engineering students as well as practising engineers with a solid foundation to help them bridge the gap between undergraduate studies on the one hand and advanced courses on mechanics and/or practical engineering problems on the other. The book contains numerous examples, along with their complete solutions. Emphasis is placed upon student participation in problem solving. The contents of the book correspond to the topics normally covered in courses on basic engineering mechanics at universities and colleges. Now in i...
Generalized quasi variational inequalities
Energy Technology Data Exchange (ETDEWEB)
Noor, M.A. [King Saud Univ., Riyadh (Saudi Arabia)
1996-12-31
In this paper, we establish the equivalence between the generalized quasi variational inequalities and the generalized implicit Wiener-Hopf equations using essentially the projection technique. This equivalence is used to suggest and analyze a number of new iterative algorithms for solving generalized quasi variational inequalities and the related complementarity problems. The convergence criteria is also considered. The results proved in this paper represent a significant improvement and refinement of the previously known results.
Problem solving through recreational mathematics
Averbach, Bonnie
1999-01-01
Historically, many of the most important mathematical concepts arose from problems that were recreational in origin. This book takes advantage of that fact, using recreational mathematics - problems, puzzles and games - to teach students how to think critically. Encouraging active participation rather than just observation, the book focuses less on mathematical results than on how these results can be applied to thinking about problems and solving them. Each chapter contains a diverse array of problems in such areas as logic, number and graph theory, two-player games of strategy, solitaire ga
Lucius, Aaron L.; Maluf, Nasib K.; Fischer, Christopher J.; Lohman, Timothy M.
2003-01-01
Helicase-catalyzed DNA unwinding is often studied using “all or none” assays that detect only the final product of fully unwound DNA. Even using these assays, quantitative analysis of DNA unwinding time courses for DNA duplexes of different lengths, L, using “n-step” sequential mechanisms, can reveal information about the number of intermediates in the unwinding reaction and the “kinetic step size”, m, defined as the average number of basepairs unwound between two successive rate limiting steps in the unwinding cycle. Simultaneous nonlinear least-squares analysis using “n-step” sequential mechanisms has previously been limited by an inability to float the number of “unwinding steps”, n, and m, in the fitting algorithm. Here we discuss the behavior of single turnover DNA unwinding time courses and describe novel methods for nonlinear least-squares analysis that overcome these problems. Analytic expressions for the time courses, fss(t), when obtainable, can be written using gamma and incomplete gamma functions. When analytic expressions are not obtainable, the numerical solution of the inverse Laplace transform can be used to obtain fss(t). Both methods allow n and m to be continuous fitting parameters. These approaches are generally applicable to enzymes that translocate along a lattice or require repetition of a series of steps before product formation. PMID:14507688
Lucius, Aaron L; Maluf, Nasib K; Fischer, Christopher J; Lohman, Timothy M
2003-10-01
Helicase-catalyzed DNA unwinding is often studied using "all or none" assays that detect only the final product of fully unwound DNA. Even using these assays, quantitative analysis of DNA unwinding time courses for DNA duplexes of different lengths, L, using "n-step" sequential mechanisms, can reveal information about the number of intermediates in the unwinding reaction and the "kinetic step size", m, defined as the average number of basepairs unwound between two successive rate limiting steps in the unwinding cycle. Simultaneous nonlinear least-squares analysis using "n-step" sequential mechanisms has previously been limited by an inability to float the number of "unwinding steps", n, and m, in the fitting algorithm. Here we discuss the behavior of single turnover DNA unwinding time courses and describe novel methods for nonlinear least-squares analysis that overcome these problems. Analytic expressions for the time courses, f(ss)(t), when obtainable, can be written using gamma and incomplete gamma functions. When analytic expressions are not obtainable, the numerical solution of the inverse Laplace transform can be used to obtain f(ss)(t). Both methods allow n and m to be continuous fitting parameters. These approaches are generally applicable to enzymes that translocate along a lattice or require repetition of a series of steps before product formation.
Use of EPR to Solve Biochemical Problems
Sahu, Indra D.; McCarrick, Robert M.; Lorigan, Gary A.
2013-01-01
EPR spectroscopy is a very powerful biophysical tool that can provide valuable structural and dynamic information on a wide variety of biological systems. The intent of this review is to provide a general overview for biochemists and biological researchers on the most commonly used EPR methods and how these techniques can be used to answer important biological questions. The topics discussed could easily fill one or more textbooks; thus, we present a brief background on several important biological EPR techniques and an overview of several interesting studies that have successfully used EPR to solve pertinent biological problems. The review consists of the following sections: an introduction to EPR techniques, spin labeling methods, and studies of naturally occurring organic radicals and EPR active transition metal systems which are presented as a series of case studies in which EPR spectroscopy has been used to greatly further our understanding of several important biological systems. PMID:23961941
Solving fault diagnosis problems linear synthesis techniques
Varga, Andreas
2017-01-01
This book addresses fault detection and isolation topics from a computational perspective. Unlike most existing literature, it bridges the gap between the existing well-developed theoretical results and the realm of reliable computational synthesis procedures. The model-based approach to fault detection and diagnosis has been the subject of ongoing research for the past few decades. While the theoretical aspects of fault diagnosis on the basis of linear models are well understood, most of the computational methods proposed for the synthesis of fault detection and isolation filters are not satisfactory from a numerical standpoint. Several features make this book unique in the fault detection literature: Solution of standard synthesis problems in the most general setting, for both continuous- and discrete-time systems, regardless of whether they are proper or not; consequently, the proposed synthesis procedures can solve a specific problem whenever a solution exists Emphasis on the best numerical algorithms to ...
Exploiting Quantum Resonance to Solve Combinatorial Problems
Zak, Michail; Fijany, Amir
2006-01-01
Quantum resonance would be exploited in a proposed quantum-computing approach to the solution of combinatorial optimization problems. In quantum computing in general, one takes advantage of the fact that an algorithm cannot be decoupled from the physical effects available to implement it. Prior approaches to quantum computing have involved exploitation of only a subset of known quantum physical effects, notably including parallelism and entanglement, but not including resonance. In the proposed approach, one would utilize the combinatorial properties of tensor-product decomposability of unitary evolution of many-particle quantum systems for physically simulating solutions to NP-complete problems (a class of problems that are intractable with respect to classical methods of computation). In this approach, reinforcement and selection of a desired solution would be executed by means of quantum resonance. Classes of NP-complete problems that are important in practice and could be solved by the proposed approach include planning, scheduling, search, and optimal design.
A highly accurate method to solve Fisher's equation
Indian Academy of Sciences (India)
The solution of the Helmholtz equation was approximated by a sixth-order compact finite difference. (CFD6) method in [29]. In [30], a CFD6 scheme has been presented to ... efficiency of the proposed method are reported in §3. Finally .... our discussion, one can apply the proposed method to solve the more general problem.
Solving satisfiability problems by the ground-state quantum computer
International Nuclear Information System (INIS)
Mao Wenjin
2005-01-01
A quantum algorithm is proposed to solve the satisfiability (SAT) problems by the ground-state quantum computer. The scale of the energy gap of the ground-state quantum computer is analyzed for the 3-bit exact cover problem. The time cost of this algorithm on the general SAT problems is discussed
Comparison of neural networks for solving the travelling salesman problem
Maire, La B.F.J.; Mladenov, V.M.
2012-01-01
The TSP deals with finding a shortest path through a number of cities. This seemingly simple problem is hard to solve because of the amount of possible solutions. Which is why methods that give a good suboptimal solution in a reasonable time are generally used. In this paper three methods were
Ten-Year-Old Students Solving Linear Equations
Brizuela, Barbara; Schliemann, Analucia
2004-01-01
In this article, the authors seek to re-conceptualize the perspective regarding students' difficulties with algebra. While acknowledging that students "do" have difficulties when learning algebra, they also argue that the generally espoused criteria for algebra as the ability to work with the syntactical rules for solving equations is…
Reversible Reasoning and the Working Backwards Problem Solving Strategy
Ramful, Ajay
2015-01-01
Making sense of mathematical concepts and solving mathematical problems may demand different forms of reasoning. These could be either domain-based, such as algebraic, geometric or statistical reasoning, while others are more general such as inductive/deductive reasoning. This article aims at giving visibility to a particular form of reasoning…
The Importance of Monitoring Skills in Physics Problem Solving
Ali, Marlina; Talib, Corrienna-Abd; Hasniza Ibrahim, Nor; Surif, Johari; Halim Abdullah, Abdul
2016-01-01
The purpose of this paper is to show how important "monitoring" is as metacognitive skills in solving physics problems in the field mechanics. Based on test scores, twenty one students were divided into two groups: more successful (MS) and less successful (LS) problem solvers. Students were allowed to think-aloud while they worked on…
Cognitive load and the acquisition of a problem solving skill
Hoe, van R.R.G.; Brouwer-Janse, M.D.; Harrington, T.L.
1994-01-01
Current theories of leaming consider the restructuring of the components of a weak problem solving sequence into a domain-specific procedure to be the fundamental leaming mechanism in complex knowledge domains. Within the context of cognitive load theory, there is growing evidence that applying weak
Is Word-Problem Solving a Form of Text Comprehension?
Fuchs, Lynn S.; Fuchs, Douglas; Compton, Donald L.; Hamlett, Carol L.; Wang, Amber Y.
2015-01-01
This study’s hypotheses were that (a) word-problem (WP) solving is a form of text comprehension that involves language comprehension processes, working memory, and reasoning, but (b) WP solving differs from other forms of text comprehension by requiring WP-specific language comprehension as well as general language comprehension. At the start of the 2nd grade, children (n = 206; on average, 7 years, 6 months) were assessed on general language comprehension, working memory, nonlinguistic reasoning, processing speed (a control variable), and foundational skill (arithmetic for WPs; word reading for text comprehension). In spring, they were assessed on WP-specific language comprehension, WPs, and text comprehension. Path analytic mediation analysis indicated that effects of general language comprehension on text comprehension were entirely direct, whereas effects of general language comprehension on WPs were partially mediated by WP-specific language. By contrast, effects of working memory and reasoning operated in parallel ways for both outcomes. PMID:25866461
Li, Yun; Wang, Shengpei; Pan, Chuxiong; Xue, Fushan; Xian, Junfang; Huang, Yaqi; Wang, Xiaoyi; Li, Tianzuo; He, Huiguang
2018-01-01
The mechanism of general anesthesia (GA) has been explored for hundreds of years, but unclear. Previous studies indicated a possible correlation between NREM sleep and GA. The purpose of this study is to compare them by in vivo human brain function to probe the neuromechanism of consciousness, so as to find out a clue to GA mechanism. 24 healthy participants were equally assigned to sleep or propofol sedation group by sleeping ability. EEG and Ramsay Sedation Scale were applied to determine sleep stage and sedation depth respectively. Resting-state functional magnetic resonance imaging (RS-fMRI) was acquired at each status. Regional homogeneity (ReHo) and seed-based whole brain functional connectivity maps (WB-FC maps) were compared. During sleep, ReHo primarily weakened on frontal lobe (especially preoptic area), but strengthened on brainstem. While during sedation, ReHo changed in various brain areas, including cingulate, precuneus, thalamus and cerebellum. Cingulate, fusiform and insula were concomitance of sleep and sedation. Comparing to sleep, FCs between the cortex and subcortical centers (centralized in cerebellum) were significantly attenuated under sedation. As sedation deepening, cerebellum-based FC maps were diminished, while thalamus- and brainstem-based FC maps were increased. There're huge distinctions in human brain function between sleep and GA. Sleep mainly rely on brainstem and frontal lobe function, while sedation is prone to affect widespread functional network. The most significant differences exist in the precuneus and cingulate, which may play important roles in mechanisms of inducing unconciousness by anesthetics. Institutional Review Board (IRB) ChiCTR-IOC-15007454.
Fluid Ability (Gf) and Complex Problem Solving (CPS)
Patrick Kyllonen; Cristina Anguiano Carrasco; Harrison J. Kell
2017-01-01
Complex problem solving (CPS) has emerged over the past several decades as an important construct in education and in the workforce. We examine the relationship between CPS and general fluid ability (Gf) both conceptually and empirically. A review of definitions of the two factors, prototypical tasks, and the information processing analyses of performance on those tasks suggest considerable conceptual overlap. We review three definitions of CPS: a general definition emerging from the human pr...
Search and Coherence-Building in Intuition and Insight Problem Solving
Directory of Open Access Journals (Sweden)
Michael Öllinger
2017-05-01
Full Text Available Coherence-building is a key concept for a better understanding of the underlying mechanisms of intuition and insight problem solving. There are several accounts that address certain aspects of coherence-building. However, there is still no proper framework defining the general principles of coherence-building. We propose a four-stage model of coherence-building. The first stage starts with spreading activation restricted by constraints. This dynamic is a well-defined rule based process. The second stage is characterized by detecting a coherent state. We adopted a fluency account assuming that the ease of information processing indicates the realization of a coherent state. The third stage is designated to evaluate the result of the coherence-building process and assess whether the given problem is solved or not. If the coherent state does not fit the requirements of the task, the process re-enters at stage 1. These three stages characterize intuition. For insight problem solving a fourth stage is necessary, which restructures the given representation after repeated failure, so that a new search space results. The new search space enables new coherent states. We provide a review of the most important findings, outline our model, present a large number of examples, deduce potential new paradigms and measures that might help to decipher the underlying cognitive processes.
Investigation of physics thought experiments’ effects on students’ logical problem solving skills
Directory of Open Access Journals (Sweden)
Ince Elif
2016-01-01
Full Text Available The purpose of this study, investigation of physics thought experiments’ effects on students’ logical problem-solving skills in collaborative groups. In this context, it was requested to undergraduate students who have taken General Physics I and General Physics II to develop thought experiments in order to solve daily life problems. At the next stage, students’ thought experiments were classified according to common issues in cooperative groups and were asked to try to solve the problems by using thought experiments’ process from each group. As a result of this study; students’ thought experiments related to daily life were developed and problem solving processes have been presented in detail.
DEFF Research Database (Denmark)
Barari, Amin; Ganjavi, B.; Jeloudar, M. Ghanbari
2010-01-01
and fluid mechanics. Design/methodology/approach – Two new but powerful analytical methods, namely, He's VIM and HPM, are introduced to solve some boundary value problems in structural engineering and fluid mechanics. Findings – Analytical solutions often fit under classical perturbation methods. However......, as with other analytical techniques, certain limitations restrict the wide application of perturbation methods, most important of which is the dependence of these methods on the existence of a small parameter in the equation. Disappointingly, the majority of nonlinear problems have no small parameter at all......Purpose – In the last two decades with the rapid development of nonlinear science, there has appeared ever-increasing interest of scientists and engineers in the analytical techniques for nonlinear problems. This paper considers linear and nonlinear systems that are not only regarded as general...
LEGO Robotics: An Authentic Problem Solving Tool?
Castledine, Alanah-Rei; Chalmers, Chris
2011-01-01
With the current curriculum focus on correlating classroom problem solving lessons to real-world contexts, are LEGO robotics an effective problem solving tool? This present study was designed to investigate this question and to ascertain what problem solving strategies primary students engaged with when working with LEGO robotics and whether the…
Perspectives on Problem Solving and Instruction
van Merrienboer, Jeroen J. G.
2013-01-01
Most educators claim that problem solving is important, but they take very different perspective on it and there is little agreement on how it should be taught. This article aims to sort out the different perspectives and discusses problem solving as a goal, a method, and a skill. As a goal, problem solving should not be limited to well-structured…
Applying Groebner bases to solve reduction problems for Feynman integrals
International Nuclear Information System (INIS)
Smirnov, Alexander V.; Smirnov, Vladimir A.
2006-01-01
We describe how Groebner bases can be used to solve the reduction problem for Feynman integrals, i.e. to construct an algorithm that provides the possibility to express a Feynman integral of a given family as a linear combination of some master integrals. Our approach is based on a generalized Buchberger algorithm for constructing Groebner-type bases associated with polynomials of shift operators. We illustrate it through various examples of reduction problems for families of one- and two-loop Feynman integrals. We also solve the reduction problem for a family of integrals contributing to the three-loop static quark potential
Applying Groebner bases to solve reduction problems for Feynman integrals
Energy Technology Data Exchange (ETDEWEB)
Smirnov, Alexander V. [Mechanical and Mathematical Department and Scientific Research Computer Center of Moscow State University, Moscow 119992 (Russian Federation); Smirnov, Vladimir A. [Nuclear Physics Institute of Moscow State University, Moscow 119992 (Russian Federation)
2006-01-15
We describe how Groebner bases can be used to solve the reduction problem for Feynman integrals, i.e. to construct an algorithm that provides the possibility to express a Feynman integral of a given family as a linear combination of some master integrals. Our approach is based on a generalized Buchberger algorithm for constructing Groebner-type bases associated with polynomials of shift operators. We illustrate it through various examples of reduction problems for families of one- and two-loop Feynman integrals. We also solve the reduction problem for a family of integrals contributing to the three-loop static quark potential.
The generalized spherical model of ferromagnetic films
International Nuclear Information System (INIS)
Costache, G.
1977-12-01
The D→ infinity of the D-vectorial model of a ferromagnetic film with free surfaces is exactly solved. The mathematical mechanism responsible for the onset of a phase transition in the system is a generalized sticking phenomenon. It is shown that the temperature at which the sticking appears, the transition temperature of the model is monotonously increasing with increasing the number of layers of the film, contrary to what happens in the spherical model with overall constraint. Certain correlation inequalities of Griffiths type are shown to hold. (author)
Five Generalizations About Cognitive Development.
Siegler, Robert S.
1983-01-01
Proposes five generalizations on existing knowledge, learning, and their interaction, and discusses evidence for these from recent research on children's learning, memory, conceptual understanding, and problem solving. (Author/AOS)
Mathematical mechanic using physical reasoning to solve problems
Levi, Mark
2009-01-01
Everybody knows that mathematics is indispensable to physics--imagine where we'd be today if Einstein and Newton didn't have the math to back up their ideas. But how many people realize that physics can be used to produce many astonishing and strikingly elegant solutions in mathematics? Mark Levi shows how in this delightful book, treating readers to a host of entertaining problems and mind-bending puzzlers that will amuse and inspire their inner physicist. Levi turns math and physics upside down, revealing how physics can simplify proofs and lead to quicker solutions and new theorems, and how physical solutions can illustrate why results are true in ways lengthy mathematical calculations never can
Step by Step: Biology Undergraduates’ Problem-Solving Procedures during Multiple-Choice Assessment
Prevost, Luanna B.; Lemons, Paula P.
2016-01-01
This study uses the theoretical framework of domain-specific problem solving to explore the procedures students use to solve multiple-choice problems about biology concepts. We designed several multiple-choice problems and administered them on four exams. We trained students to produce written descriptions of how they solved the problem, and this allowed us to systematically investigate their problem-solving procedures. We identified a range of procedures and organized them as domain general, domain specific, or hybrid. We also identified domain-general and domain-specific errors made by students during problem solving. We found that students use domain-general and hybrid procedures more frequently when solving lower-order problems than higher-order problems, while they use domain-specific procedures more frequently when solving higher-order problems. Additionally, the more domain-specific procedures students used, the higher the likelihood that they would answer the problem correctly, up to five procedures. However, if students used just one domain-general procedure, they were as likely to answer the problem correctly as if they had used two to five domain-general procedures. Our findings provide a categorization scheme and framework for additional research on biology problem solving and suggest several important implications for researchers and instructors. PMID:27909021
[Out of hopelessness--problem solving training in suicide prevention].
Perczel Forintos, Dóra; Póos, Judit
2008-01-01
Psychological studies have great importance in suicide prevention since psychological factors belong to the modifiable risk factors in suicide. These are the negative cognitive triad and hopelessness which are related to vague, over-generalized autobiographical memory and lead to poor problem solving abilities. In this paper we review the most relevant clinical psychology studies and models such as the cognitive model of suicide as well as the entrapment theory by Williams (2004). In the second part we describe the frequently used method of problem solving training/therapy which can be used in either individual or group format. We hope that the problem solving skill training will soon become a part of suicide prevention in Hungary also, since short,focused and evidence based interventions are much needed in psychiatric care.
Solving Math Problems Approximately: A Developmental Perspective.
Directory of Open Access Journals (Sweden)
Dana Ganor-Stern
Full Text Available Although solving arithmetic problems approximately is an important skill in everyday life, little is known about the development of this skill. Past research has shown that when children are asked to solve multi-digit multiplication problems approximately, they provide estimates that are often very far from the exact answer. This is unfortunate as computation estimation is needed in many circumstances in daily life. The present study examined 4th graders, 6th graders and adults' ability to estimate the results of arithmetic problems relative to a reference number. A developmental pattern was observed in accuracy, speed and strategy use. With age there was a general increase in speed, and an increase in accuracy mainly for trials in which the reference number was close to the exact answer. The children tended to use the sense of magnitude strategy, which does not involve any calculation but relies mainly on an intuitive coarse sense of magnitude, while the adults used the approximated calculation strategy which involves rounding and multiplication procedures, and relies to a greater extent on calculation skills and working memory resources. Importantly, the children were less accurate than the adults, but were well above chance level. In all age groups performance was enhanced when the reference number was smaller (vs. larger than the exact answer and when it was far (vs. close from it, suggesting the involvement of an approximate number system. The results suggest the existence of an intuitive sense of magnitude for the results of arithmetic problems that might help children and even adults with difficulties in math. The present findings are discussed in the context of past research reporting poor estimation skills among children, and the conditions that might allow using children estimation skills in an effective manner.
Kim, Dong Hyup; Kim, So Youn
Block copolymers (BCPs) can be self-assembled forming periodic nanostructures, which have been employed in many applications. While general agreements exist for the phase diagrams of BCP self-assembly in bulk or thin films, a fundamental understanding of BCP structures at the air/water interface still remain elusive. The current study explains morphology transition of BCPs with relative fraction of each block at the air/water interface: block fraction is the only parameter to control the morphology. In this study, we show morphology transitions from spherical to cylindrical and planar structures with neat polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) via reducing the spreading area of BCP solution at the air/water interface. For example, PS-b-P2VP in a fixed block fraction known to form only spheres can experience sphere to cylinder or lamellar transitions depending on the spreading area at the air/water interface. Suggesting a new parameter to control the interfacial assembly of BCPs, a complete phase diagram is drawn with two paramters: relative block fraction and spreading area. We also explain the morphology transition with the combinational description of dewetting mechanism and spring effect of hydrophilic block.
Chuderski, Adam; Jastrzębski, Jan
2018-02-01
A battery comprising 4 fluid reasoning tests as well as 13 working memory (WM) tasks that involved storage, recall, updating, binding, and executive control, was applied to 318 adults in order to evaluate the true relationship of reasoning ability and WM capacity (WMC) to insight problem solving, measured using 40 verbal, spatial, math, matchstick, and remote associates problems (insight problems). WMC predicted 51.8% of variance in insight problem solving and virtually explained its almost isomorphic link to reasoning ability (84.6% of shared variance). The strong link between WMC and insight pertained generally to most WM tasks and insight problems, was identical for problems solved with and without reported insight, was linear throughout the ability levels, and was not mediated by age, motivation, anxiety, psychoticism, and openness to experience. In contrast to popular views on the sudden and holistic nature of insight, the solving of insight problems results primarily from typical operations carried out by the basic WM mechanisms that are responsible for the maintenance, retrieval, transformation, and control of information in the broad range of intellectual tasks (including fluid reasoning). Little above and beyond WM is unique about insight. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Generalized Superconductivity. Generalized Levitation
International Nuclear Information System (INIS)
Ciobanu, B.; Agop, M.
2004-01-01
In the recent papers, the gravitational superconductivity is described. We introduce the concept of generalized superconductivity observing that any nongeodesic motion and, in particular, the motion in an electromagnetic field, can be transformed in a geodesic motion by a suitable choice of the connection. In the present paper, the gravitoelectromagnetic London equations have been obtained from the generalized Helmholtz vortex theorem using the generalized local equivalence principle. In this context, the gravitoelectromagnetic Meissner effect and, implicitly, the gravitoelectromagnetic levitation are given. (authors)
Community-powered problem solving.
Gouillart, Francis; Billings, Douglas
2013-04-01
Traditionally, companies have managed their constituencies with specific processes: marketing to customers, procuring from vendors, developing HR policies for employees, and so on. The problem is, such processes focus on repeatability and compliance, so they can lead to stagnation. Inviting your constituencies to collectively help you solve problems and exploit opportunities--"co-creation"--is a better approach. It allows you to continually tap the skills and insights of huge numbers of stakeholders and develop new ways to produce value for all. The idea is to provide stakeholders with platforms (physical and digital forums) on which they can interact, get them to start exploring new experiences and connections, and let the system grow organically. A co-creation initiative by a unit of Becton, Dickinson and Company demonstrates how this works. A global leader in syringes, BD set out to deepen its ties with hospital customers and help them reduce the incidence of infections from unsafe injection and syringe disposal practices. The effort began with a cross-functional internal team, brought in the hospital procurement and supply managers BD had relationships with, and then reached out to hospitals' infection-prevention and occupational health leaders. Eventually product designers, nurses, sustainability staffers, and even hospital CFOs were using the platform, contributing data that generated new best practices and reduced infections.
Students’ difficulties in probabilistic problem-solving
Arum, D. P.; Kusmayadi, T. A.; Pramudya, I.
2018-03-01
There are many errors can be identified when students solving mathematics problems, particularly in solving the probabilistic problem. This present study aims to investigate students’ difficulties in solving the probabilistic problem. It focuses on analyzing and describing students errors during solving the problem. This research used the qualitative method with case study strategy. The subjects in this research involve ten students of 9th grade that were selected by purposive sampling. Data in this research involve students’ probabilistic problem-solving result and recorded interview regarding students’ difficulties in solving the problem. Those data were analyzed descriptively using Miles and Huberman steps. The results show that students have difficulties in solving the probabilistic problem and can be divided into three categories. First difficulties relate to students’ difficulties in understanding the probabilistic problem. Second, students’ difficulties in choosing and using appropriate strategies for solving the problem. Third, students’ difficulties with the computational process in solving the problem. Based on the result seems that students still have difficulties in solving the probabilistic problem. It means that students have not able to use their knowledge and ability for responding probabilistic problem yet. Therefore, it is important for mathematics teachers to plan probabilistic learning which could optimize students probabilistic thinking ability.
IDEAL Problem Solving dalam Pembelajaran Matematika
Directory of Open Access Journals (Sweden)
Eny Susiana
2012-01-01
Full Text Available Most educators agree that problem solving is among the most meaningful and importantkinds of learning and thingking. That is, the central focus of learning and instructionshould be learning to solve problems. There are several warrants supporting that claims.They are authenticity, relevance, problem solving engages deeper learning angtherefore enhances meaning making, and constructed to represent problems (problemsolving is more meaningful. It is the reason why we must provide teaching and learningto make studentâ€™s problem solving skill in progress. There are many informationprocessingmodels of problem solving, such as simplified model of the problem-solvingprocess by Gicks, Polyaâ€™s problem solving process etc. One of them is IDEAL problemsolving. Each letter of IDEAL is stand for an aspect of thinking that is important forproblem solving. IDEAL is identify problem, Define Goal, Explore possible strategies,Anticipate outcme and Act, and Look back and learn. Using peer interaction andquestion prompt in small group in IDEAL problem solving teaching and Learning canimprove problem solving skill.Kata kunci: IDEAL Problem Solving, Interaksi Sebaya, Pertanyaan Penuntun, KelompokKecil.
Problem-Solving After Traumatic Brain Injury in Adolescence: Associations With Functional Outcomes.
Wade, Shari L; Cassedy, Amy E; Fulks, Lauren E; Taylor, H Gerry; Stancin, Terry; Kirkwood, Michael W; Yeates, Keith O; Kurowski, Brad G
2017-08-01
To examine the association of problem-solving with functioning in youth with traumatic brain injury (TBI). Cross-sectional evaluation of pretreatment data from a randomized controlled trial. Four children's hospitals and 1 general hospital, with level 1 trauma units. Youth, ages 11 to 18 years, who sustained moderate or severe TBI in the last 18 months (N=153). Problem-solving skills were assessed using the Social Problem-Solving Inventory (SPSI) and the Dodge Social Information Processing Short Stories. Everyday functioning was assessed based on a structured clinical interview using the Child and Adolescent Functional Assessment Scale (CAFAS) and via adolescent ratings on the Youth Self Report (YSR). Correlations and multiple regression analyses were used to examine associations among measures. The TBI group endorsed lower levels of maladaptive problem-solving (negative problem orientation, careless/impulsive responding, and avoidant style) and lower levels of rational problem-solving, resulting in higher total problem-solving scores for the TBI group compared with a normative sample (Pproblem-solving composites were associated with overall functioning on the CAFAS, only maladaptive problem-solving (PProblem-solving after TBI differs from normative samples and is associated with functional impairments. The relation of problem-solving deficits after TBI with global functioning merits further investigation, with consideration of the potential effects of problem-solving interventions on functional outcomes. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
Students’ Algebraic Reasonsing In Solving Mathematical Problems With Adversity Quotient
Aryani, F.; Amin, S. M.; Sulaiman, R.
2018-01-01
Algebraic reasoning is a process in which students generalize mathematical ideas from a set of particular instances and express them in increasingly formal and age-appropriate ways. Using problem solving approach to develop algebraic reasoning of mathematics may enhace the long-term learning trajectory of the majority students. The purpose of this research was to describe the algebraic reasoning of quitter, camper, and climber junior high school students in solving mathematical problems. This research used qualitative descriptive method. Subjects were determined by purposive sampling. The technique of collecting data was done by task-based interviews.The results showed that the algebraic reasoning of three students in the process of pattern seeking by identifying the things that are known and asked in a similar way. But three students found the elements of pattern recognition in different ways or method. So, they are generalize the problem of pattern formation with different ways. The study of algebraic reasoning and problem solving can be a learning paradigm in the improve students’ knowledge and skills in algebra work. The goal is to help students’ improve academic competence, develop algebraic reasoning in problem solving.
DEFF Research Database (Denmark)
Hattel, Jesper; Hansen, Preben
1995-01-01
This paper presents a novel control volume based FD method for solving the equilibrium equations in terms of displacements, i.e. the generalized Navier equations. The method is based on the widely used cv-FDM solution of heat conduction and fluid flow problems involving a staggered grid formulati....... The resulting linear algebraic equations are solved by line-Gauss-Seidel....
Application of Homotopy Analysis Method to Solve Relativistic Toda Lattice System
International Nuclear Information System (INIS)
Wang Qi
2010-01-01
In this letter, the homotopy analysis method is successfully applied to solve the Relativistic Toda lattice system. Comparisons are made between the results of the proposed method and exact solutions. Analysis results show that homotopy analysis method is a powerful and easy-to-use analytic tool to solve systems of differential-difference equations. (general)
OECD Publishing, 2016
2016-01-01
The education sector performs well for information and communication technology (ICT) and problem-solving skills, although it still lags behind the professional, scientific and technical activities sector. Primary and secondary teachers have better ICT and problem-solving skills than the general population, and similar skills to other…
The Relationships of Problem Solving Styles to Parenting Styles: Two Studies
Neyen, Julia; Volpe, Carolyn Ann; Selby, Edwin C.; Houtz, John C.
2017-01-01
Two independent studies were conducted to examine the relationship of problem solving styles to parenting styles. Both studies used VIEW: An Assessment of Problem Solving Style and the Parental Authority Questionnaire (PAQ). Study 1 included 173 adults recruited using Mechanical Turk and Study 2 included 131 adults recruited using Qualtrics. Data…
Neto, Ary Serpa; Hemmes, Sabrine N T; Barbas, Carmen S V; Beiderlinden, Martin; Fernandez-Bustamante, Ana; Futier, Emmanuel; Gajic, Ognjen; El-Tahan, Mohamed R; Ghamdi, Abdulmohsin A Al; Günay, Ersin; Jaber, Samir; Kokulu, Serdar; Kozian, Alf; Licker, Marc; Lin, Wen-Qian; Maslow, Andrew D; Memtsoudis, Stavros G; Reis Miranda, Dinis; Moine, Pierre; Ng, Thomas; Paparella, Domenico; Ranieri, V Marco; Scavonetto, Federica; Schilling, Thomas; Selmo, Gabriele; Severgnini, Paolo; Sprung, Juraj; Sundar, Sugantha; Talmor, Daniel; Treschan, Tanja; Unzueta, Carmen; Weingarten, Toby N; Wolthuis, Esther K; Wrigge, Hermann; Amato, Marcelo B P; Costa, Eduardo L V; de Abreu, Marcelo Gama; Pelosi, Paolo; Schultz, Marcus J
2016-04-01
Protective mechanical ventilation strategies using low tidal volume or high levels of positive end-expiratory pressure (PEEP) improve outcomes for patients who have had surgery. The role of the driving pressure, which is the difference between the plateau pressure and the level of positive end-expiratory pressure is not known. We investigated the association of tidal volume, the level of PEEP, and driving pressure during intraoperative ventilation with the development of postoperative pulmonary complications. We did a meta-analysis of individual patient data from randomised controlled trials of protective ventilation during general anesthaesia for surgery published up to July 30, 2015. The main outcome was development of postoperative pulmonary complications (postoperative lung injury, pulmonary infection, or barotrauma). We included data from 17 randomised controlled trials, including 2250 patients. Multivariate analysis suggested that driving pressure was associated with the development of postoperative pulmonary complications (odds ratio [OR] for one unit increase of driving pressure 1·16, 95% CI 1·13-1·19; pprotective ventilation on development of pulmonary complications (p=0·027). In two studies that compared low with high PEEP during low tidal volume ventilation, an increase in the level of PEEP that resulted in an increase in driving pressure was associated with more postoperative pulmonary complications (OR 3·11, 95% CI 1·39-6·96; p=0·006). In patients having surgery, intraoperative high driving pressure and changes in the level of PEEP that result in an increase of driving pressure are associated with more postoperative pulmonary complications. However, a randomised controlled trial comparing ventilation based on driving pressure with usual care is needed to confirm these findings. None. Copyright © 2016 Elsevier Ltd. All rights reserved.
Molecular mechanisms of cancer
National Research Council Canada - National Science Library
Weber, Georg F
2007-01-01
... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Section I. General Mechanisms of Transformation 1. Theories of Carcinogenesis...
Recent developments in quantum mechanics
International Nuclear Information System (INIS)
Piron, C.
1989-01-01
It is essentially a review of recent progress in Quantum Mechanics obtained by the ''Geneva School'', put all together in a synthesis for the first time. During these twelve last years Quantum Mechanics has developed deeply in three aspects: 1) the interpretation has been completely clarified but many ''senior'' physicists delight in the mystery of their school-days Quantum Mechanics and do not want to change their minds. 2) The formalism has been developed and generalized to many (if it is not all) physical situations. 3) Many new rules of calculation have been developed. In conclusion many paradoxes and/or unsolved problems have been solved and many calculations which usually appear just as tricks can be explained and justified. I want here to give a brief survey of each one of these three points and to end by some examples which show the power and the efficiency of this new theory. (orig.)
Conceptual problem solving in high school physics
Jennifer L. Docktor; Natalie E. Strand; José P. Mestre; Brian H. Ross
2015-01-01
Problem solving is a critical element of learning physics. However, traditional instruction often emphasizes the quantitative aspects of problem solving such as equations and mathematical procedures rather than qualitative analysis for selecting appropriate concepts and principles. This study describes the development and evaluation of an instructional approach called Conceptual Problem Solving (CPS) which guides students to identify principles, justify their use, and plan their solution in w...
Solving global optimization problems on GPU cluster
Energy Technology Data Exchange (ETDEWEB)
Barkalov, Konstantin; Gergel, Victor; Lebedev, Ilya [Lobachevsky State University of Nizhni Novgorod, Gagarin Avenue 23, 603950 Nizhni Novgorod (Russian Federation)
2016-06-08
The paper contains the results of investigation of a parallel global optimization algorithm combined with a dimension reduction scheme. This allows solving multidimensional problems by means of reducing to data-independent subproblems with smaller dimension solved in parallel. The new element implemented in the research consists in using several graphic accelerators at different computing nodes. The paper also includes results of solving problems of well-known multiextremal test class GKLS on Lobachevsky supercomputer using tens of thousands of GPU cores.
General Reducibility and Solvability of Polynomial Equations ...
African Journals Online (AJOL)
General Reducibility and Solvability of Polynomial Equations. ... Unlike quadratic, cubic, and quartic polynomials, the general quintic and higher degree polynomials cannot be solved algebraically in terms of finite number of additions, ... Galois Theory, Solving Polynomial Systems, Polynomial factorization, Polynomial Ring ...
Applying Cooperative Techniques in Teaching Problem Solving
Directory of Open Access Journals (Sweden)
Krisztina Barczi
2013-12-01
Full Text Available Teaching how to solve problems – from solving simple equations to solving difficult competition tasks – has been one of the greatest challenges for mathematics education for many years. Trying to find an effective method is an important educational task. Among others, the question arises as to whether a method in which students help each other might be useful. The present article describes part of an experiment that was designed to determine the effects of cooperative teaching techniques on the development of problem-solving skills.
Assertiveness and problem solving in midwives.
Yurtsal, Zeliha Burcu; Özdemir, Levent
2015-01-01
Midwifery profession is required to bring solutions to problems and a midwife is expected to be an assertive person and to develop midwifery care. This study was planned to examine the relationship between assertiveness and problem-solving skills of midwives. This cross-sectional study was conducted with 201 midwives between July 2008 and February 2009 in the city center of Sivas. The Rathus Assertiveness Schedule (RAS) and Problem Solving Inventory (PSI) were used to determine the level of assertiveness and problem-solving skills of midwives. Statistical methods were used as mean, standard deviation, percentage, Student's T, ANOVA and Tukey HSD, Kruskal Wallis, Fisher Exact, Pearson Correlation and Chi-square tests and P problem-solving skills training. A statistically significant negative correlation was found between the RAS and PSI scores. The RAS scores decreased while the problem-solving scores increased (r: -0451, P problem solving skills of midwives, and midwives who were assertive solved their problems better than did others. Assertiveness and problem-solving skills training will contribute to the success of the midwifery profession. Midwives able to solve problems, and display assertive behaviors will contribute to the development of midwifery profession.
An Integrated Architecture for Engineering Problem Solving
National Research Council Canada - National Science Library
Pisan, Yusuf
1998-01-01
.... This thesis describes the Integrated Problem Solving Architecture (IPSA) that combines qualitative, quantitative and diagrammatic reasoning skills to produce annotated solutions to engineering problems...
International Nuclear Information System (INIS)
Nicklisch, F.
1984-01-01
Growing complexity of technical matter has meant that technical expertise is called upon in more and more legal proceedings. The technical expert is, in general terms, the mediator between technology and the law, he is also entrusted with the task of pointing up the differences in approach and in the nature of authority in these two areas and thus paving the way for mutual understanding. The evaluation of the technical expert's opinion is one of the cardinal problems bound up with the role of the expert in legal procedure. After the presentation of the expert's opinion, the judge is supposed to possess so much specialised knowledge that he can assess the opinion itself in scientific and technical respects and put his finger on any errors the expert may have made. This problem can only be solved via an assessment opinion. First of all, the opinion can be assessed indirectly via evaluation of the credentials and the neutrality and independence of the expert. In direct terms, the opinion can be subjected to a certain - albeit restricted - scrutiny, whether it is generally convincing, as far as the layman is competent to judge. This interpretation alone makes it possible to classify and integrate legally the technical standards and regulations represent expert statements on the scientific and technical theorems based on the knowledge and experience gained in a given area. They are designed to reflect prevailing opinion among leading representatives of the profession and can thus themselves be regarded as expert opinions. As a rule, these opinions will have such weight that - other than in exceptional cases - they will not be invalidated in procedure by deviating opinions from individual experts. (orig./HSCH) [de
Wave Mechanics or Wave Statistical Mechanics
International Nuclear Information System (INIS)
Qian Shangwu; Xu Laizi
2007-01-01
By comparison between equations of motion of geometrical optics and that of classical statistical mechanics, this paper finds that there should be an analogy between geometrical optics and classical statistical mechanics instead of geometrical mechanics and classical mechanics. Furthermore, by comparison between the classical limit of quantum mechanics and classical statistical mechanics, it finds that classical limit of quantum mechanics is classical statistical mechanics not classical mechanics, hence it demonstrates that quantum mechanics is a natural generalization of classical statistical mechanics instead of classical mechanics. Thence quantum mechanics in its true appearance is a wave statistical mechanics instead of a wave mechanics.
Spencer, A J M
2004-01-01
The mechanics of fluids and the mechanics of solids represent the two major areas of physics and applied mathematics that meet in continuum mechanics, a field that forms the foundation of civil and mechanical engineering. This unified approach to the teaching of fluid and solid mechanics focuses on the general mechanical principles that apply to all materials. Students who have familiarized themselves with the basic principles can go on to specialize in any of the different branches of continuum mechanics. This text opens with introductory chapters on matrix algebra, vectors and Cartesian ten
Solve the Dilemma of Over-Simplification
Schmitt, Gerhard
Complexity science can help to understand the functioning and the interaction of the components of a city. In 1965, Christopher Alexander gave in his book A city is not a tree a description of the complex nature of urban organization. At this time, neither high-speed computers nor urban big data existed. Today, Luis Bettencourt et al. use complexity science to analyze data for countries, regions, or cities. The results can be used globally in other cities. Objectives of complexity science with regard to future cities are the observation and identification of tendencies and regularities in behavioral patterns, and to find correlations between them and spatial configurations. Complex urban systems cannot be understood in total yet. But research focuses on describing the system by finding some simple, preferably general and emerging patterns and rules that can be used for urban planning. It is important that the influencing factors are not just geo-spatial patterns but also consider variables which are important for the design quality. Complexity science is a way to solve the dilemma of oversimplification of insights from existing cities and their applications to new cities. An example: The effects of streets, public places and city structures on citizens and their behavior depend on how they are perceived. To describe this perception, it is not sufficient to consider only particular characteristics of the urban environment. Different aspects play a role and influence each other. Complexity science could take this fact into consideration and handle the non-linearity of the system...
A Framework for Distributed Problem Solving
Leone, Joseph; Shin, Don G.
1989-03-01
This work explores a distributed problem solving (DPS) approach, namely the AM/AG model, to cooperative memory recall. The AM/AG model is a hierarchic social system metaphor for DPS based on the Mintzberg's model of organizations. At the core of the model are information flow mechanisms, named amplification and aggregation. Amplification is a process of expounding a given task, called an agenda, into a set of subtasks with magnified degree of specificity and distributing them to multiple processing units downward in the hierarchy. Aggregation is a process of combining the results reported from multiple processing units into a unified view, called a resolution, and promoting the conclusion upward in the hierarchy. The combination of amplification and aggregation can account for a memory recall process which primarily relies on the ability of making associations between vast amounts of related concepts, sorting out the combined results, and promoting the most plausible ones. The amplification process is discussed in detail. An implementation of the amplification process is presented. The process is illustrated by an example.
Exp-function method for solving Maccari's system
International Nuclear Information System (INIS)
Zhang Sheng
2007-01-01
In this Letter, the Exp-function method is used to seek exact solutions of Maccari's system. As a result, single and combined generalized solitonary solutions are obtained, from which some known solutions obtained by extended sine-Gordon equation method and improved hyperbolic function method are recovered as special cases. It is shown that the Exp-function method provides a very effective and powerful mathematical tool for solving nonlinear evolution equations in mathematical physics
Distance Measurement Solves Astrophysical Mysteries
2003-08-01
Location, location, and location. The old real-estate adage about what's really important proved applicable to astrophysics as astronomers used the sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA) to pinpoint the distance to a pulsar. Their accurate distance measurement then resolved a dispute over the pulsar's birthplace, allowed the astronomers to determine the size of its neutron star and possibly solve a mystery about cosmic rays. "Getting an accurate distance to this pulsar gave us a real bonanza," said Walter Brisken, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Monogem Ring The Monogem Ring, in X-Ray Image by ROSAT satellite CREDIT: Max-Planck Institute, American Astronomical Society (Click on Image for Larger Version) The pulsar, called PSR B0656+14, is in the constellation Gemini, and appears to be near the center of a circular supernova remnant that straddles Gemini and its neighboring constellation, Monoceros, and is thus called the Monogem Ring. Since pulsars are superdense, spinning neutron stars left over when a massive star explodes as a supernova, it was logical to assume that the Monogem Ring, the shell of debris from a supernova explosion, was the remnant of the blast that created the pulsar. However, astronomers using indirect methods of determining the distance to the pulsar had concluded that it was nearly 2500 light-years from Earth. On the other hand, the supernova remnant was determined to be only about 1000 light-years from Earth. It seemed unlikely that the two were related, but instead appeared nearby in the sky purely by a chance juxtaposition. Brisken and his colleagues used the VLBA to make precise measurements of the sky position of PSR B0656+14 from 2000 to 2002. They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. This effect, called parallax, provides a direct measurement of
Wavelet Methods for Solving Fractional Order Differential Equations
A. K. Gupta; S. Saha Ray
2014-01-01
Fractional calculus is a field of applied mathematics which deals with derivatives and integrals of arbitrary orders. The fractional calculus has gained considerable importance during the past decades mainly due to its application in diverse fields of science and engineering such as viscoelasticity, diffusion of biological population, signal processing, electromagnetism, fluid mechanics, electrochemistry, and many more. In this paper, we review different wavelet methods for solving both linea...
Galerkin projection methods for solving multiple related linear systems
Energy Technology Data Exchange (ETDEWEB)
Chan, T.F.; Ng, M.; Wan, W.L.
1996-12-31
We consider using Galerkin projection methods for solving multiple related linear systems A{sup (i)}x{sup (i)} = b{sup (i)} for 1 {le} i {le} s, where A{sup (i)} and b{sup (i)} are different in general. We start with the special case where A{sup (i)} = A and A is symmetric positive definite. The method generates a Krylov subspace from a set of direction vectors obtained by solving one of the systems, called the seed system, by the CG method and then projects the residuals of other systems orthogonally onto the generated Krylov subspace to get the approximate solutions. The whole process is repeated with another unsolved system as a seed until all the systems are solved. We observe in practice a super-convergence behaviour of the CG process of the seed system when compared with the usual CG process. We also observe that only a small number of restarts is required to solve all the systems if the right-hand sides are close to each other. These two features together make the method particularly effective. In this talk, we give theoretical proof to justify these observations. Furthermore, we combine the advantages of this method and the block CG method and propose a block extension of this single seed method. The above procedure can actually be modified for solving multiple linear systems A{sup (i)}x{sup (i)} = b{sup (i)}, where A{sup (i)} are now different. We can also extend the previous analytical results to this more general case. Applications of this method to multiple related linear systems arising from image restoration and recursive least squares computations are considered as examples.
International Nuclear Information System (INIS)
Kwon, Yeong Sik; Lee, Dong Seop; Ryu, Haung Ryong; Jang, Cheol Hyeon; Choi, Bong Jong; Choi, Sang Won
1993-07-01
The book concentrates on the latest general chemistry, which is divided int twenty-three chapters. It deals with basic conception and stoichiometry, nature of gas, structure of atoms, quantum mechanics, symbol and structure of an electron of ion and molecule, chemical thermodynamics, nature of solid, change of state and liquid, properties of solution, chemical equilibrium, solution and acid-base, equilibrium of aqueous solution, electrochemistry, chemical reaction speed, molecule spectroscopy, hydrogen, oxygen and water, metallic atom; 1A, IIA, IIIA, carbon and atom IVA, nonmetal atom and an inert gas, transition metals, lanthanons, and actinoids, nuclear properties and radioactivity, biochemistry and environment chemistry.
Creativity and Insight in Problem Solving
Golnabi, Laura
2016-01-01
This paper analyzes the thought process involved in problem solving and its categorization as creative thinking as defined by psychologist R. Weisberg (2006). Additionally, the notion of insight, sometimes present in unconscious creative thinking and often leading to creative ideas, is discussed in the context of geometry problem solving. In…
Metacognition: Student Reflections on Problem Solving
Wismath, Shelly; Orr, Doug; Good, Brandon
2014-01-01
Twenty-first century teaching and learning focus on the fundamental skills of critical thinking and problem solving, creativity and innovation, and collaboration and communication. Metacognition is a crucial aspect of both problem solving and critical thinking, but it is often difficult to get students to engage in authentic metacognitive…
Parallel Algorithm Solves Coupled Differential Equations
Hayashi, A.
1987-01-01
Numerical methods adapted to concurrent processing. Algorithm solves set of coupled partial differential equations by numerical integration. Adapted to run on hypercube computer, algorithm separates problem into smaller problems solved concurrently. Increase in computing speed with concurrent processing over that achievable with conventional sequential processing appreciable, especially for large problems.
Measuring Problem Solving Skills in "Portal 2"
Shute, Valerie J.; Wang, Lubin
2013-01-01
This paper examines possible improvement to problem solving skills as a function of playing the video game "Portal 2." Stealth assessment is used in the game to evaluate students' problem solving abilities--specifically basic and flexible rule application. The stealth assessment measures will be validated against commonly accepted…
Conceptual Problem Solving in High School Physics
Docktor, Jennifer L.; Strand, Natalie E.; Mestre, José P.; Ross, Brian H.
2015-01-01
Problem solving is a critical element of learning physics. However, traditional instruction often emphasizes the quantitative aspects of problem solving such as equations and mathematical procedures rather than qualitative analysis for selecting appropriate concepts and principles. This study describes the development and evaluation of an…
Concept mapping instrumental support for problem solving
Stoyanov, S.; Stoyanov, Slavi; Kommers, Petrus A.M.
2008-01-01
The main theoretical position of this paper is that it is the explicit problem-solving support in concept mapping software that produces a stronger effect in problem-solving performance than the implicit support afforded by the graphical functionality of concept mapping software. Explicit
Problem Solving Methods in Engineering Design
DEFF Research Database (Denmark)
Hartvig, Susanne C
1999-01-01
This short paper discusses typical engineering tasks and problem solving methods, based on a field study of engineering tasks at a Danish engineering firm. The field study has identified ten classes of design tasks and in this paper these classes are related to problem solving methods. The descri...
The Process of Solving Complex Problems
Fischer, Andreas; Greiff, Samuel; Funke, Joachim
2012-01-01
This article is about Complex Problem Solving (CPS), its history in a variety of research domains (e.g., human problem solving, expertise, decision making, and intelligence), a formal definition and a process theory of CPS applicable to the interdisciplinary field. CPS is portrayed as (a) knowledge acquisition and (b) knowledge application…
Strategy Keys as Tools for Problem Solving
Herold-Blasius, Raja
2017-01-01
Problem solving is one of the main competences we seek to teach students at school for use in their future lives. However, when dealing with mathematical problems, teachers encounter a wide variety of difficulties. To foster students' problem-solving skills, the authors developed "strategy keys." Strategy keys can serve as material to…
Problem Solving Strategies among Primary School Teachers
Yew, Wun Thiam; Lian, Lim Hooi; Meng, Chew Cheng
2017-01-01
The purpose of this article was to examine problem solving strategies among primary school teachers. The researchers employed survey research design to examine their problem solving strategies. The participants of this study consisted of 120 primary school teachers from a public university in Peninsula Malaysia who enrolled in a 4-year Graduating…
Teaching Effective Problem Solving Strategies for Interns
Warren, Louis L.
2005-01-01
This qualitative study investigates what problem solving strategies interns learn from their clinical teachers during their internships. Twenty-four interns who completed their internship in the elementary grades shared what problem solving strategies had the greatest impact upon them in learning how to deal with problems during their internship.…
Some Applications of Algebraic System Solving
Roanes-Lozano, Eugenio
2011-01-01
Technology and, in particular, computer algebra systems, allows us to change both the way we teach mathematics and the mathematical curriculum. Curiously enough, unlike what happens with linear system solving, algebraic system solving is not widely known. The aim of this paper is to show that, although the theory lying behind the "exact…
Mathematical problem solving in primary school
Kolovou, A.
2011-01-01
A student is engaged in (non-routine) problem solving when there is no clear pathway to the solution. In contrast to routine problems, non-routine ones cannot be solved through the direct application of a standard procedure. Consider the following problem: In a quiz you get two points for each
A Multivariate Model of Physics Problem Solving
Taasoobshirazi, Gita; Farley, John
2013-01-01
A model of expertise in physics problem solving was tested on undergraduate science, physics, and engineering majors enrolled in an introductory-level physics course. Structural equation modeling was used to test hypothesized relationships among variables linked to expertise in physics problem solving including motivation, metacognitive planning,…
Solving applied mathematical problems with Matlab
Xue, Dingyu
2008-01-01
Computer Mathematics Language-An Overview. Fundamentals of MATLAB Programming. Calculus Problems. MATLAB Computations of Linear Algebra Problems. Integral Transforms and Complex Variable Functions. Solutions to Nonlinear Equations and Optimization Problems. MATLAB Solutions to Differential Equation Problems. Solving Interpolations and Approximations Problems. Solving Probability and Mathematical Statistics Problems. Nontraditional Solution Methods for Mathematical Problems.
King, Sun-Kun
1996-01-01
The variances of the quantum-mechanical noise in a two-input-port Michelson interferometer within the framework of the Loudon-Ni model were solved exactly in two general cases: (1) one coherent state input and one squeezed state input, and (2) two photon number states inputs. Low intensity limit, exponential decaying signal and the noise due to mixing were discussed briefly.
Hassan Fathabadi
2013-01-01
In this study, several novel numerical solutions are presented to solve the turbulent filtration equation and its special case called “Non-Newtonian mechanical filtration equation”. The turbulent filtration equation in porous media is a very important equation which has many applications to solve the problems appearing especially in mechatronics, micro mechanic and fluid mechanic. Many applied mechanical problems can be solved using this equation. For example, non-Newtonian mechanical filtrat...
Self-Assessment of Problem Solving Disposition in Medical Students
Directory of Open Access Journals (Sweden)
Silvia Lizett Olivares-Olivares
2014-01-01
Full Text Available Medical schools are committed to both students and society to develop capabilities required to succeed in health care environments. Present diagnosis and treatment methods become obsolete faster, demanding that medical schools incorporate competency-based education to keep pace with future demands. This study was conducted to assess the problem solving disposition of medical students. A three-subcategory model of the skill is proposed. The instrument was validated on content by a group of 17 experts in medical education and applied to 135 registered students on the sixth year of the M.D. Physician Surgeon program at a private medical school. Cronbach’s alpha indicated an internal consistency of 0.751. The findings suggest that selected items have both homogeneity and validity. The factor analysis resulted in components that were associated with three problem-solving subcategories. The students’ perceptions are higher in the pattern recognition and application of general strategies for problem solving subcategories of the Problem solving disposition model.
Psychosocial dimensions of solving an indoor air problem.
Lahtinen, Marjaana; Huuhtanen, Pekka; Kähkönen, Erkki; Reijula, Kari
2002-03-01
This investigation focuses on the psychological and social dimensions of managing and solving indoor air problems. The data were collected in nine workplaces by interviews (n = 85) and questionnaires (n = 375). Indoor air problems in office environments have traditionally utilized industrial hygiene or technical expertise. However, indoor air problems at workplaces are often more complex issues to solve. Technical questions are inter-related with the dynamics of the work community, and the cooperation and interaction skills of the parties involved in the solving process are also put to the test. In the present study, the interviewees were very critical of the process of solving the indoor air problem. The responsibility for coordinating the problem-managing process was generally considered vague, as were the roles and functions of the various parties. Communication problems occurred and rumors about the indoor air problem circulated widely. Conflicts were common, complicating the process in several ways. The research focused on examining different ways of managing and resolving an indoor air problem. In addition, reference material on the causal factors of the indoor air problem was also acquired. The study supported the hypothesis that psychosocial factors play a significant role in indoor air problems.
Kamis, Arnold; Khan, Beverly K.
2009-01-01
How do we model and improve technical problem solving, such as network subnetting? This paper reports an experimental study that tested several hypotheses derived from Kolb's experiential learning cycle and Huber's problem solving model. As subjects solved a network subnetting problem, they mapped their mental processes according to Huber's…
Aljaberi, Nahil M.; Gheith, Eman
2016-01-01
This study aims to investigate the ability of pre-service class teacher at University of Petrain solving mathematical problems using Polya's Techniques, their level of problem solving skills in daily-life issues. The study also investigates the correlation between their ability to solve mathematical problems and their level of problem solving…
Perez, Nestor
2017-01-01
The second edition of this textbook includes a refined presentation of concepts in each chapter, additional examples; new problems and sections, such as conformal mapping and mechanical behavior of wood; while retaining all the features of the original book. The material included in this book is based upon the development of analytical and numerical procedures pertinent to particular fields of linear elastic fracture mechanics (LEFM) and plastic fracture mechanics (PFM), including mixed-mode-loading interaction. The mathematical approach undertaken herein is coupled with a brief review of several fracture theories available in cited references, along with many color images and figures. Dynamic fracture mechanics is included through the field of fatigue and Charpy impact testing. Explains computational and engineering approaches for solving crack-related problems using straightforward mathematics that facilitate comprehension of the physical meaning of crack growth processes; Expands computational understandin...
Solving large mixed linear models using preconditioned conjugate gradient iteration.
Strandén, I; Lidauer, M
1999-12-01
Continuous evaluation of dairy cattle with a random regression test-day model requires a fast solving method and algorithm. A new computing technique feasible in Jacobi and conjugate gradient based iterative methods using iteration on data is presented. In the new computing technique, the calculations in multiplication of a vector by a matrix were recorded to three steps instead of the commonly used two steps. The three-step method was implemented in a general mixed linear model program that used preconditioned conjugate gradient iteration. Performance of this program in comparison to other general solving programs was assessed via estimation of breeding values using univariate, multivariate, and random regression test-day models. Central processing unit time per iteration with the new three-step technique was, at best, one-third that needed with the old technique. Performance was best with the test-day model, which was the largest and most complex model used. The new program did well in comparison to other general software. Programs keeping the mixed model equations in random access memory required at least 20 and 435% more time to solve the univariate and multivariate animal models, respectively. Computations of the second best iteration on data took approximately three and five times longer for the animal and test-day models, respectively, than did the new program. Good performance was due to fast computing time per iteration and quick convergence to the final solutions. Use of preconditioned conjugate gradient based methods in solving large breeding value problems is supported by our findings.
Generalized Born Models of Macromolecular Solvation Effects
Bashford, Donald; Case, David A.
2000-10-01
It would often be useful in computer simulations to use a simple description of solvation effects, instead of explicitly representing the individual solvent molecules. Continuum dielectric models often work well in describing the thermodynamic aspects of aqueous solvation, and approximations to such models that avoid the need to solve the Poisson equation are attractive because of their computational efficiency. Here we give an overview of one such approximation, the generalized Born model, which is simple and fast enough to be used for molecular dynamics simulations of proteins and nucleic acids. We discuss its strengths and weaknesses, both for its fidelity to the underlying continuum model and for its ability to replace explicit consideration of solvent molecules in macromolecular simulations. We focus particularly on versions of the generalized Born model that have a pair-wise analytical form, and therefore fit most naturally into conventional molecular mechanics calculations.
Electrospun Nanofibers: Solving Global Issues
Si, Yang; Tang, Xiaomin; Yu, Jianyong; Ding, Bin
Energy and environment will head the list of top global issues facing society for the next 50 years. Nanotechnology is responding to these challenges by designing and fabricating functional nanofibers optimized for energy and environmental applications. The route toward these nano-objects is based primarily on electrospinning: a highly versatile method that allows the fabrication of continuous fibers with diameters down to a few nanometers. The mechanism responsible for the fiber formation mainly includes the Taylor Cone theory and flight-instability theory, which can be predicted theoretically and controlled experimentally. Moreover, the electrospinning has been applied to natural polymers, synthetic polymers, ceramics, and carbon. Fibers with complex architectures, such as ribbon fiber, porous fiber, core-shell fiber, or hollow fiber, can be produced by special electrospinning methods. It is also possible to produce nanofibrous membranes with designed aggregate structure including alignment, patterning, and two-dimensional nanonets. Finally, the brief analysis of nanofibers used for advanced energy and environmental applications in the past decade indicates that their impact has been realized well and is encouraging, and will continually represent a key technology to ensure sustainable energy and preserve our environment for the future.
Solving the wrong hierarchy problem
International Nuclear Information System (INIS)
Blinov, Nikita; Hook, Anson
2016-01-01
Many theories require augmenting the Standard Model with additional scalar fields with large order one couplings. We present a new solution to the hierarchy problem for these scalar fields. We explore parity- and Z_2-symmetric theories where the Standard Model Higgs potential has two vacua. The parity or Z_2 copy of the Higgs lives in the minimum far from the origin while our Higgs occupies the minimum near the origin of the potential. This approach results in a theory with multiple light scalar fields but with only a single hierarchy problem, since the bare mass is tied to the Higgs mass by a discrete symmetry. The new scalar does not have a new hierarchy problem associated with it because its expectation value and mass are generated by dimensional transmutation of the scalar quartic coupling. The location of the second Higgs minimum is not a free parameter, but is rather a function of the matter content of the theory. As a result, these theories are extremely predictive. We develop this idea in the context of a solution to the strong CP problem. Lastly, we show this mechanism postdicts the top Yukawa to be within 1σ of the currently measured value and predicts scalar color octets with masses in the range 9-200 TeV
Atom Wavelike Nature Solved Mathematically
Sven, Charles
2010-03-01
Like N/S poles of a magnet the strong force field surrounding, confining the nucleus exerts an equal force [noted by this author] driving electrons away from the attraction of positively charged protons force fields in nucleus -- the mechanics for wavelike nature of electron. Powerful forces corral closely packed protons within atomic nucleus with a force that is at least a million times stronger than proton's electrical attraction that binds electrons. This then accounts for the ease of electron manipulation in that electron is already pushed away by the very strong atomic N/S force field; allowing electrons to drive photons when I strike a match. Ageless atom's electron requirements, used to drive light/photons or atom bomb, without batteries, must be supplied from a huge, external, super high frequency, super-cooled source, undetected by current technology, one that could exist 14+ billion years without degradation -- filling a limitless space prior to Big Bang. Using only replicable physics, I show how our Universe emanated from that event.
Bubble collisions in general relativity
International Nuclear Information System (INIS)
Siklos, S.T.C.; Wu, Z.C.; University of Science and Technology of China, Hofei, Anhwei)
1983-01-01
The collision of two bubbles of true vacuum in a background of false vacuum is considered in the context of General Relativity. It is found that in the thin wall approximation, the problem, can be solved exactly. The region to the future of the collision is described by the pseudo-Schwarzschild de Sitter metric. The parameters in this metric are found by solving the junction conditions at each collision. (author)
Tchantchaleishvili, Vakhtang; Umakanthan, Ramanan; Karp, Seth; Stulak, John M; Keebler, Mary E; Maltais, Simon
2013-05-01
Multiple complications are associated with use of ventricular assist devices (VADs). Cardiac-related complications and infections are most frequently reported. VADs, however, can also lead to a number of general surgical complications equally significant in terms of morbidity and mortality. The authors performed a systematic literature search to review current data that specifically relate general surgical complications to patients who undergo left VAD implantation. The review provides a relatively clear understanding of the spectrum of general surgical complications and shows that they contribute significantly to morbidity and mortality in these patients.
Solving the flavour problem in supersymmetric Standard Models with three Higgs families
International Nuclear Information System (INIS)
Howl, R.; King, S.F.
2010-01-01
We show how a non-Abelian family symmetry Δ 27 can be used to solve the flavour problem of supersymmetric Standard Models containing three Higgs families such as the Exceptional Supersymmetric Standard Model (E 6 SSM). The three 27-dimensional families of the E 6 SSM, including the three families of Higgs fields, transform in a triplet representation of the Δ 27 family symmetry, allowing the family symmetry to commute with a possible high energy E 6 symmetry. The Δ 27 family symmetry here provides a high energy understanding of the Z 2 H symmetry of the E 6 SSM, which solves the flavour changing neutral current problem of the three families of Higgs fields. The main phenomenological predictions of the model are tri-bi-maximal mixing for leptons, two almost degenerate LSPs and two almost degenerate families of colour triplet D-fermions, providing a clear prediction for the LHC. In addition the model predicts PGBs with masses below the TeV scale, and possibly much lighter, which appears to be a quite general and robust prediction of all models based on the D-term vacuum alignment mechanism.
PSQP: Puzzle Solving by Quadratic Programming.
Andalo, Fernanda A; Taubin, Gabriel; Goldenstein, Siome
2017-02-01
In this article we present the first effective method based on global optimization for the reconstruction of image puzzles comprising rectangle pieces-Puzzle Solving by Quadratic Programming (PSQP). The proposed novel mathematical formulation reduces the problem to the maximization of a constrained quadratic function, which is solved via a gradient ascent approach. The proposed method is deterministic and can deal with arbitrary identical rectangular pieces. We provide experimental results showing its effectiveness when compared to state-of-the-art approaches. Although the method was developed to solve image puzzles, we also show how to apply it to the reconstruction of simulated strip-shredded documents, broadening its applicability.
Do job demands and job control affect problem-solving?
Bergman, Peter N; Ahlberg, Gunnel; Johansson, Gun; Stoetzer, Ulrich; Aborg, Carl; Hallsten, Lennart; Lundberg, Ingvar
2012-01-01
The Job Demand Control model presents combinations of working conditions that may facilitate learning, the active learning hypothesis, or have detrimental effects on health, the strain hypothesis. To test the active learning hypothesis, this study analysed the effects of job demands and job control on general problem-solving strategies. A population-based sample of 4,636 individuals (55% women, 45% men) with the same job characteristics measured at two times with a three year time lag was used. Main effects of demands, skill discretion, task authority and control, and the combined effects of demands and control were analysed in logistic regressions, on four outcomes representing general problem-solving strategies. Those reporting high on skill discretion, task authority and control, as well as those reporting high demand/high control and low demand/high control job characteristics were more likely to state using problem solving strategies. Results suggest that working conditions including high levels of control may affect how individuals cope with problems and that workplace characteristics may affect behaviour in the non-work domain.
Students' self-explanations while solving unfamiliar cases: the role of biomedical knowledge.
Chamberland, Martine; Mamede, Sílvia; St-Onge, Christina; Rivard, Marc-Antoine; Setrakian, Jean; Lévesque, Annie; Lanthier, Luc; Schmidt, Henk G; Rikers, Remy M J P
2013-11-01
General guidelines for teaching clinical reasoning have received much attention, despite a paucity of instructional approaches with demonstrated effectiveness. As suggested in a recent experimental study, self-explanation while solving clinical cases may be an effective strategy to foster reasoning in clinical clerks dealing with less familiar cases. However, the mechanisms that mediate this benefit have not been specifically investigated. The aim of this study was to explore the types of knowledge used by students when solving familiar and less familiar clinical cases with self-explanation. In a previous study, 36 third-year medical students diagnosed familiar and less familiar clinical cases either by engaging in self-explanation or not. Based on an analysis of previously collected data, the present study compared the content of self-explanation protocols generated by seven randomly selected students while solving four familiar and four less familiar cases. In total, 56 verbal protocols (28 familiar and 28 less familiar) were segmented and coded using the following categories: paraphrases, biomedical inferences, clinical inferences, monitoring statements and errors. Students provided more self-explanation segments from less familiar cases (M = 275.29) than from familiar cases (M = 248.71, p = 0.046). They provided significantly more paraphrases (p = 0.001) and made more errors (p = 0.008). A significant interaction was found between familiarity and the type of inferences (biomedical versus clinical, p = 0.016). When self-explaining less familiar cases, students provided significantly more biomedical inferences than familiar cases. Lack of familiarity with a case seems to stimulate medical students to engage in more extensive thinking during self-explanation. Less familiar cases seem to activate students' biomedical knowledge, which in turn helps them to create new links between biomedical and clinical knowledge, and eventually construct a more coherent mental
Environmental problem-solving: Psychosocial factors
Miller, Alan
1982-11-01
This is a study of individual differences in environmental problem-solving, the probable roots of these differences, and their implications for the education of resource professionals. A group of student Resource Managers were required to elaborate their conception of a complex resource issue (Spruce Budworm management) and to generate some ideas on management policy. Of particular interest was the way in which subjects dealt with the psychosocial aspects of the problem. A structural and content analysis of responses indicated a predominance of relatively compartmentalized styles, a technological orientation, and a tendency to ignore psychosocial issues. A relationship between problem-solving behavior and personal (psychosocial) style was established which, in the context of other evidence, suggests that problem-solving behavior is influenced by more deep seated personality factors. The educational implication drawn was that problem-solving cannot be viewed simply as an intellectual-technical activity but one that involves, and requires the education of, the whole person.
Improving mathematical problem solving : A computerized approach
Harskamp, EG; Suhre, CJM
Mathematics teachers often experience difficulties in teaching students to become skilled problem solvers. This paper evaluates the effectiveness of two interactive computer programs for high school mathematics problem solving. Both programs present students with problems accompanied by instruction
Indoor Air Quality Problem Solving Tool
Use the IAQ Problem Solving Tool to learn about the connection between health complaints and common solutions in schools. This resource provides an easy, step-by-step process to start identifying and resolving IAQ problems found at your school.
Problem solving using soft systems methodology.
Land, L
This article outlines a method of problem solving which considers holistic solutions to complex problems. Soft systems methodology allows people involved in the problem situation to have control over the decision-making process.
Exact Algorithms for Solving Stochastic Games
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Koucky, Michal; Lauritzen, Niels
2012-01-01
Shapley's discounted stochastic games, Everett's recursive games and Gillette's undiscounted stochastic games are classical models of game theory describing two-player zero-sum games of potentially infinite duration. We describe algorithms for exactly solving these games....
How to solve applied mathematics problems
Moiseiwitsch, B L
2011-01-01
This workbook bridges the gap between lectures and practical applications, offering students of mathematics, engineering, and physics the chance to practice solving problems from a wide variety of fields. 2011 edition.
Physics: Quantum problems solved through games
Maniscalco, Sabrina
2016-04-01
Humans are better than computers at performing certain tasks because of their intuition and superior visual processing. Video games are now being used to channel these abilities to solve problems in quantum physics. See Letter p.210
Generalized quantum statistics
International Nuclear Information System (INIS)
Chou, C.
1992-01-01
In the paper, a non-anyonic generalization of quantum statistics is presented, in which Fermi-Dirac statistics (FDS) and Bose-Einstein statistics (BES) appear as two special cases. The new quantum statistics, which is characterized by the dimension of its single particle Fock space, contains three consistent parts, namely the generalized bilinear quantization, the generalized quantum mechanical description and the corresponding statistical mechanics
Modelling human problem solving with data from an online game.
Rach, Tim; Kirsch, Alexandra
2016-11-01
Since the beginning of cognitive science, researchers have tried to understand human strategies in order to develop efficient and adequate computational methods. In the domain of problem solving, the travelling salesperson problem has been used for the investigation and modelling of human solutions. We propose to extend this effort with an online game, in which instances of the travelling salesperson problem have to be solved in the context of a game experience. We report on our effort to design and run such a game, present the data contained in the resulting openly available data set and provide an outlook on the use of games in general for cognitive science research. In addition, we present three geometrical models mapping the starting point preferences in the problems presented in the game as the result of an evaluation of the data set.
EISPACK-J: subprogram package for solving eigenvalue problems
International Nuclear Information System (INIS)
Fujimura, Toichiro; Tsutsui, Tsuneo
1979-05-01
EISPACK-J, a subprogram package for solving eigenvalue problems, has been developed and subprograms with a variety of functions have been prepared. These subprograms can solve standard problems of complex matrices, general problems of real matrices and special problems in which only the required eigenvalues and eigenvectors are calculated. They are compared to existing subprograms, showing their features through benchmark tests. Many test problems, including realistic scale problems, are provided for the benchmark tests. Discussions are made on computer core storage and computing time required for each subprogram, and accuracy of the solution. The results show that the subprograms of EISPACK-J, based on Householder, QR and inverse iteration methods, are the best in computing time and accuracy. (author)
The art and science of problem solving
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui
2005-01-01
In this paper we will document that real-life problem solving in complex situations demands both rational (scientific) and intuitive (artistic) thinking. First, the concepts of art and science will be discussed; differences and similarities will be enhanced. Thereafter the concept of group problem...... solving facilitation both as science and art will be presented. A case study related to examination's planning will be discussed to illustrate the main concepts in practice. In addition, other cases studies will also be shortly presented....
Local Strategy Improvement for Parity Game Solving
Friedmann, Oliver; Lange, Martin
2010-01-01
The problem of solving a parity game is at the core of many problems in model checking, satisfiability checking and program synthesis. Some of the best algorithms for solving parity game are strategy improvement algorithms. These are global in nature since they require the entire parity game to be present at the beginning. This is a distinct disadvantage because in many applications one only needs to know which winning region a particular node belongs to, and a witnessing winning strategy may...
Cross, Fiona R; Jackson, Robert R
2015-03-01
Intricate predatory strategies are widespread in the salticid subfamily Spartaeinae. The hypothesis we consider here is that the spartaeine species that are proficient at solving prey-capture problems are also proficient at solving novel problems. We used nine species from this subfamily in our experiments. Eight of these species (two Brettus, one Cocalus, three Cyrba, two Portia) are known for specialized invasion of other spiders' webs and for actively choosing other spiders as preferred prey ('araneophagy'). Except for Cocalus, these species also use trial and error to derive web-based signals with which they gain dynamic fine control of the resident spider's behaviour ('aggressive mimicry').The ninth species, Paracyrba wanlessi, is not araneophagic and instead specializes at preying on mosquitoes. We presented these nine species with a novel confinement problem that could be solved by trial and error. The test spider began each trial on an island in a tray of water, with an atoll surrounding the island. From the island, the spider could choose between two potential escape tactics (leap or swim), but we decided at random before the trial which tactic would fail and which tactic would achieve partial success. Our findings show that the seven aggressive-mimic species are proficient at solving the confinement problem by repeating 'correct' choices and by switching to the alternative tactic after making an 'incorrect' choice. However, as predicted, there was no evidence of C. gibbosus or P. wanlessi, the two non-aggressive-mimic species, solving the confinement problem. We discuss these findings in the context of an often-made distinction between domain-specific and domain-general cognition.
Quantum mechanical streamlines. I - Square potential barrier
Hirschfelder, J. O.; Christoph, A. C.; Palke, W. E.
1974-01-01
Exact numerical calculations are made for scattering of quantum mechanical particles hitting a square two-dimensional potential barrier (an exact analog of the Goos-Haenchen optical experiments). Quantum mechanical streamlines are plotted and found to be smooth and continuous, to have continuous first derivatives even through the classical forbidden region, and to form quantized vortices around each of the nodal points. A comparison is made between the present numerical calculations and the stationary wave approximation, and good agreement is found between both the Goos-Haenchen shifts and the reflection coefficients. The time-independent Schroedinger equation for real wavefunctions is reduced to solving a nonlinear first-order partial differential equation, leading to a generalization of the Prager-Hirschfelder perturbation scheme. Implications of the hydrodynamical formulation of quantum mechanics are discussed, and cases are cited where quantum and classical mechanical motions are identical.
International Nuclear Information System (INIS)
Bureau, D.
2000-05-01
Among the various existing incentive mechanisms for the abatement of greenhouse gas emissions, like the pollution regulations and the financial help for energy mastery, this document analyzes the conditions of efficiency of the negotiated voluntary agreements and of the tradable emission quotas and their articulation with the fiscality. (J.S.)