Analytical solutions to matrix diffusion problems
Kekäläinen, Pekka
2014-10-06
We report an analytical method to solve in a few cases of practical interest the equations which have traditionally been proposed for the matrix diffusion problem. In matrix diffusion, elements dissolved in ground water can penetrate the porous rock surronuding the advective flow paths. In the context of radioactive waste repositories this phenomenon provides a mechanism by which the area of rock surface in contact with advecting elements is greatly enhanced, and can thus be an important delay mechanism. The cases solved are relevant for laboratory as well for in situ experiments. Solutions are given as integral representations well suited for easy numerical solution.
Analytic prediction of airplane equilibrium spin characteristics
NASA Technical Reports Server (NTRS)
Adams, W. M., Jr.
1972-01-01
The nonlinear equations of motion are solved algebraically for conditions for which an airplane is in an equilibrium spin. Constrained minimization techniques are employed in obtaining the solution. Linear characteristics of the airplane about the equilibrium points are also presented and their significance in identifying the stability characteristics of the equilibrium points is discussed. Computer time requirements are small making the method appear potentially applicable in airplane design. Results are obtained for several configurations and are compared with other analytic-numerical methods employed in spin prediction. Correlation with experimental results is discussed for one configuration for which a rather extensive data base was available. A need is indicated for higher Reynolds number data taken under conditions which more accurately simulate a spin.
Approximated analytical solution to an Ebola optimal control problem
NASA Astrophysics Data System (ADS)
Hincapié-Palacio, Doracelly; Ospina, Juan; Torres, Delfim F. M.
2016-11-01
An analytical expression for the optimal control of an Ebola problem is obtained. The analytical solution is found as a first-order approximation to the Pontryagin Maximum Principle via the Euler-Lagrange equation. An implementation of the method is given using the computer algebra system Maple. Our analytical solutions confirm the results recently reported in the literature using numerical methods.
Eco-analytical Methodology in Environmental Problems Monitoring
NASA Astrophysics Data System (ADS)
Agienko, M. I.; Bondareva, E. P.; Chistyakova, G. V.; Zhironkina, O. V.; Kalinina, O. I.
2017-01-01
Among the problems common to all mankind, which solutions influence the prospects of civilization, the problem of ecological situation monitoring takes very important place. Solution of this problem requires specific methodology based on eco-analytical comprehension of global issues. Eco-analytical methodology should help searching for the optimum balance between environmental problems and accelerating scientific and technical progress. The fact that Governments, corporations, scientists and nations focus on the production and consumption of material goods cause great damage to environment. As a result, the activity of environmentalists is developing quite spontaneously, as a complement to productive activities. Therefore, the challenge posed by the environmental problems for the science is the formation of geo-analytical reasoning and the monitoring of global problems common for the whole humanity. So it is expected to find the optimal trajectory of industrial development to prevent irreversible problems in the biosphere that could stop progress of civilization.
Computational neural networks driving complex analytical problem solving.
Hanrahan, Grady
2010-06-01
Neural network computing demonstrates advanced analytical problem solving abilities to meet the demands of modern chemical research. (To listen to a podcast about this article, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html .).
Geometric and analytic problems on bicomplex plane
NASA Astrophysics Data System (ADS)
Dimiev, Stancho; Stoev, Peter; Stoilova, Stanislava
2015-11-01
Let us recall that the bicomplex plane is a complex ring of complex dimension 2. It consists of couples of the kind (z, w) = z + jw, where z and w are complex numbers and j is a symbol with the property j2 = -1. We note that the bicomplex plane admits singular points. The set of these singular points coincides with the cross-choped set of complex bisectrices (z, ±z), z is a complex. The main problem in the function theory on the bicomplex plane is to describe the interconnection between the same theory of the cross-choped subset and whole bicomplex plane. The first theory is of one complex variable and the second one is of two complex variables. Another problems are related with the comformal mappings and the movement of a partials of this subset on the whole one. Presented paper is a start studies in this direction.
Assessing Cognitive Learning of Analytical Problem Solving
NASA Astrophysics Data System (ADS)
Billionniere, Elodie V.
Introductory programming courses, also known as CS1, have a specific set of expected outcomes related to the learning of the most basic and essential computational concepts in computer science (CS). However, two of the most often heard complaints in such courses are that (1) they are divorced from the reality of application and (2) they make the learning of the basic concepts tedious. The concepts introduced in CS1 courses are highly abstract and not easily comprehensible. In general, the difficulty is intrinsic to the field of computing, often described as "too mathematical or too abstract." This dissertation presents a small-scale mixed method study conducted during the fall 2009 semester of CS1 courses at Arizona State University. This study explored and assessed students' comprehension of three core computational concepts---abstraction, arrays of objects, and inheritance---in both algorithm design and problem solving. Through this investigation students' profiles were categorized based on their scores and based on their mistakes categorized into instances of five computational thinking concepts: abstraction, algorithm, scalability, linguistics, and reasoning. It was shown that even though the notion of computational thinking is not explicit in the curriculum, participants possessed and/or developed this skill through the learning and application of the CS1 core concepts. Furthermore, problem-solving experiences had a direct impact on participants' knowledge skills, explanation skills, and confidence. Implications for teaching CS1 and for future research are also considered.
Analytic semigroups: Applications to inverse problems for flexible structures
NASA Technical Reports Server (NTRS)
Banks, H. T.; Rebnord, D. A.
1990-01-01
Convergence and stability results for least squares inverse problems involving systems described by analytic semigroups are presented. The practical importance of these results is demonstrated by application to several examples from problems of estimation of material parameters in flexible structures using accelerometer data.
Does Incubation Enhance Problem Solving? A Meta-Analytic Review
ERIC Educational Resources Information Center
Sio, Ut Na; Ormerod, Thomas C.
2009-01-01
A meta-analytic review of empirical studies that have investigated incubation effects on problem solving is reported. Although some researchers have reported increased solution rates after an incubation period (i.e., a period of time in which a problem is set aside prior to further attempts to solve), others have failed to find effects. The…
Does Incubation Enhance Problem Solving? A Meta-Analytic Review
ERIC Educational Resources Information Center
Sio, Ut Na; Ormerod, Thomas C.
2009-01-01
A meta-analytic review of empirical studies that have investigated incubation effects on problem solving is reported. Although some researchers have reported increased solution rates after an incubation period (i.e., a period of time in which a problem is set aside prior to further attempts to solve), others have failed to find effects. The…
On analytic design of loudspeaker arrays with uniform radiation characteristics
Aarts; Janssen
2000-01-01
Some notes on analytical derived loudspeaker arrays with uniform radiation characteristics are presented. The array coefficients are derived via analytical means and compared with so-called maximal flat sequences known from telecommunications and information theory. It appears that the newly derived array, i.e., the quadratic phase array, has a higher efficiency than the Bessel array and a flatter response than the Barker array. The method discussed admits generalization to the design of arrays with desired nonuniform radiating characteristics.
Analytical calculation of intracellular calcium wave characteristics.
Kupferman, R; Mitra, P P; Hohenberg, P C; Wang, S S
1997-06-01
We present a theoretical analysis of intracellular calcium waves propagated by calcium feedback at the inositol 1,4,5-trisphosphate (IP3) receptor. The model includes essential features of calcium excitability, but is still analytically tractable. Formulas are derived for the wave speed, amplitude, and width. The calculations take into account cytoplasmic Ca buffering, the punctate nature of the Ca release channels, channel inactivation, and Ca pumping. For relatively fast buffers, the wave speed is well approximated by V(infinity) = (J(eff)D(eff)/C0)1/2, where J(eff) is an effective, buffered source strength; D(eff) is the effective, buffered diffusion constant of Ca; and C(0) is the Ca threshold for channel activation. It is found that the saturability and finite on-rate of buffers must be taken into account to accurately derive the wave speed and front width. The time scale governing Ca wave propagation is T(r), the time for Ca release to reach threshold to activate further release. Because IP3 receptor inactivation is slow on this time scale, channel inactivation does not affect the wave speed. However, inactivation competes with Ca removal to limit wave height and front length, and for biological parameter ranges, it is inactivation that determines these parameters. Channel discreteness introduces only small corrections to wave speed relative to a model in which Ca is released uniformly from the surface of the stores. These calculations successfully predict experimental results from basic channel and cell parameters and explain the slowing of waves by exogenous buffers.
Problem Solving, Reasoning, and Analytical Thinking in a Classroom Environment
ERIC Educational Resources Information Center
Robbins, Joanne K.
2011-01-01
Problem solving, reasoning, and analytical thinking are defined and described as teachable repertoires. This paper describes work performed at a school serving special needs children, Morningside Academy, that has resulted in specific procedures developed over the past 15 years. These procedures include modifying "Think Aloud Pair Problem…
An analytically solvable eigenvalue problem for the linear elasticity equations.
Day, David Minot; Romero, Louis Anthony
2004-07-01
Analytic solutions are useful for code verification. Structural vibration codes approximate solutions to the eigenvalue problem for the linear elasticity equations (Navier's equations). Unfortunately the verification method of 'manufactured solutions' does not apply to vibration problems. Verification books (for example [2]) tabulate a few of the lowest modes, but are not useful for computations of large numbers of modes. A closed form solution is presented here for all the eigenvalues and eigenfunctions for a cuboid solid with isotropic material properties. The boundary conditions correspond physically to a greased wall.
Problems encountered during impact calculations using analytic equations of state
Kerrisk, J.F.; Harvey, W.B.
1997-02-01
During modeling of the impact of a projectile on a target or other calculations that bring materials together at high velocities, computer simulations of materials being shocked to high pressure and then releasing to low pressure are performed. Depending on the circumstances, the release to low pressure is often accompanied by release to a very low density. Numerical problems leading to very large sound speeds (and thus small time steps) or to negative Lagrangian volumes have been encountered during MESA-2D calculations of this nature. These problems can be traced to the behavior of the equation of state (EOS) in the limit as the density becomes much less than the normal or reference density. Although analytic solutions for expansion isentropes may show acceptable behavior in the low-density limit, numerical solutions can show undesirable behavior. Examples of this undesirable behavior in the low-density regime are given for some simple, analytic equations of state that have closed-form solutions for isentropes. The behavior of three analytic EOSs that are frequently used in MESA-2D calculations are then discussed. These EOSs are the Los Alamos EOS, the MESA polynomial EOS, and a Mie-Gruneisen EOS based on a linear relation between shock and particle velocity. The problems in the low-density region can be corrected for the Los Alamos EOS and the MESA polynomial EOS by the proper choice of EOS coefficients in the expansion region (density less than the reference density). Problems with the Mie-Gruneisen EOS can be corrected if the functional relationship between the Gruneisen parameter ({Tau}) and density differs above and below the reference density.
Does incubation enhance problem solving? A meta-analytic review.
Sio, Ut Na; Ormerod, Thomas C
2009-01-01
A meta-analytic review of empirical studies that have investigated incubation effects on problem solving is reported. Although some researchers have reported increased solution rates after an incubation period (i.e., a period of time in which a problem is set aside prior to further attempts to solve), others have failed to find effects. The analysis examined the contributions of moderators such as problem type, presence of solution-relevant or misleading cues, and lengths of preparation and incubation periods to incubation effect sizes. The authors identified a positive incubation effect, with divergent thinking tasks benefiting more than linguistic and visual insight tasks from incubation. Longer preparation periods gave a greater incubation effect, whereas filling an incubation period with high cognitive demand tasks gave a smaller incubation effect. Surprisingly, low cognitive demand tasks yielded a stronger incubation effect than did rest during an incubation period when solving linguistic insight problems. The existence of multiple types of incubation effect provides evidence for differential invocation of knowledge-based vs. strategic solution processes across different classes of problem, and it suggests that the conditions under which incubation can be used as a practical technique for enhancing problem solving must be designed with care.
Unified analytical solutions to two-body problems with drag
NASA Astrophysics Data System (ADS)
Breiter, S.; Jackson, A. A.
1998-08-01
The two-body problem with a generalized Stokes drag is discussed. The drag force is proportional to the product of the velocity vector and the inverse square of the distance. The generalization consists of allowing two different proportionality constants for the radial and the transverse components of the force. Under the `generalized Robertson transformation', the equation of the orbit takes the form of the Lommel equation and admits solutions in terms of Bessel and Lommel functions. The exact, analytical solutions for this type of drag reveal a paradoxical effect of increasing eccentricity for all trajectories. The Poynting-Robertson drag and Poynting-Plummer-Danby problems are discussed as particular cases of the general solution.
An analytic model for MODFET capacitance-voltage characteristics
NASA Astrophysics Data System (ADS)
George, G.; Hauser, John R.
1990-05-01
An analytic model for the capacitance-voltage (C-V) characteristics of n-channel modulation doped FETs (MODFETs) is derived. Gauss law is used to relate the net areal gate charge density in an AlGaAs/GaAs MODFET to the electric field intensity at the metal-AlGaAs interface. An analytic expression for the electric field intensity which accounts for the neutralization of donors and the generation of free electrons is derived. The gate capacitance is derived as a closed-form analytic function of the gate voltage. The expression derived is easily computable and affords physical insight. The results, when compared with numerical calculations and experimental data, yield good agreement over a wide range of gate voltages.
Extension of a combined analytical/numerical initial value problem solver for unsteady periodic flow
NASA Astrophysics Data System (ADS)
de Chant, Lawrence J.; Seidel, Jonathan A.; Kline, Teresa R.
2002-11-01
Here we describe analytical and numerical modifications that extend the Differential Reduced Ejector/ mixer Analysis (DREA), a combined analytical/numerical, multiple species ejector/mixing code developed for preliminary design applications, to apply to periodic unsteady flow. An unsteady periodic flow modelling capability opens a range of pertinent simulation problems including pulse detonation engines (PDE), internal combustion engine ICE applications, mixing enhancement and more fundamental fluid dynamic unsteadiness, e.g. fan instability/vortex shedding problems. Although mapping between steady and periodic forms for a scalar equation is a classical problem in applied mathematics, we will show that extension to systems of equations and, moreover, problems with complex initial conditions are more challenging. Additionally, the inherent large gradient initial condition singularities that are characteristic of mixing flows and that have greatly influenced the DREA code formulation, place considerable limitations on the use of numerical solution methods. Fortunately, using the combined analytical-numerical form of the DREA formulation, a successful formulation is developed and described. Comparison of this method with experimental measurements for jet flows with excitation shows reasonable agreement with the simulation. Other flow fields are presented to demonstrate the capabilities of the model. As such, we demonstrate that unsteady periodic effects can be included within the simple, efficient, coarse grid DREA implementation that has been the original intent of the DREA development effort, namely, to provide a viable tool where more complex and expensive models are inappropriate.
The Finite Analytic Method for steady and unsteady heat transfer problems
NASA Technical Reports Server (NTRS)
Chen, C.-J.; Li, P.
1980-01-01
A new numerical method called the Finite Analytical Method for solving partial differential equations is introduced. The basic idea of the finite analytic method is the incorporation of the local analytic solution in obtaining the numerical solution of the problem. The finite analytical method first divides the total region of the problem into small subregions in which local analytic solutions are obtained. Then an algebraic equation is derived from the local analytic solution for each subregion relating an interior nodal value at a point P in the subregion to its neighboring nodal values. The assembly of all the local analytic solutions thus provides the finite-analytic numerical solution of the problem. In this paper the finite analytic method is illustrated in solving steady and unsteady heat transfer problems.
Killeen, Anthony A; Long, Tom; Souers, Rhona; Styer, Patricia; Ventura, Christina B; Klee, George G
2014-09-01
Both the regulations in the Clinical Laboratory Improvement Amendments of 1988 (CLIA) and the checklists of the College of American Pathologists (CAP) Laboratory Accreditation Program require clinical laboratories to verify performance characteristics of quantitative test systems. Laboratories must verify performance claims when introducing an unmodified, US Food and Drug Administration-cleared or approved test system, and they must comply with requirements for periodic calibration and calibration verification for existing test systems. They must also periodically verify the analytical measurement range of many quantitative test systems. To provide definitions for many of the terms used in these regulations, to describe a set of basic analyses that laboratories may adapt to demonstrate compliance with both CLIA and the CAP Laboratory Accreditation Program checklists for performing calibration verification and for verifying the analytical measurement range of test systems, to review some of the recommended procedures for establishing performance goals, and to provide data illustrating the performance goals used in some of the CAP's calibration verification and linearity surveys. The CAP's calibration verification and linearity survey programs, the CLIA regulations, the Laboratory Accreditation Program requirements, and published literature were used to meet these objectives. Calibration verification and linearity and analytical measurement range verification should be performed using suitable materials with assessment of results using well-defined evaluation protocols. We describe the CAP's calibration verification and linearity programs that may be used for these purposes.
Konovalov, Aleksandr B; Vlasov, V V; Kalintsev, A G; Lyubimov, Vladimir V; Kravtsenyuk, Olga V
2006-11-30
The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions. (special issue devoted to multiple radiation scattering in random media)
Analytical and Numerical Studies of Several Fluid Mechanical Problems
NASA Astrophysics Data System (ADS)
Kong, D. L.
2014-03-01
In this thesis, three parts, each with several chapters, are respectively devoted to hydrostatic, viscous, and inertial fluids theories and applications. Involved topics include planetary, biological fluid systems, and high performance computing technology. In the hydrostatics part, the classical Maclaurin spheroids theory is generalized, for the first time, to a more realistic multi-layer model, establishing geometries of both the outer surface and the interfaces. For one of its astrophysical applications, the theory explicitly predicts physical shapes of surface and core-mantle-boundary for layered terrestrial planets, which enables the studies of some gravity problems, and the direct numerical simulations of dynamo flows in rotating planetary cores. As another application of the figure theory, the zonal flow in the deep atmosphere of Jupiter is investigated for a better understanding of the Jovian gravity field. An upper bound of gravity field distortions, especially in higher-order zonal gravitational coefficients, induced by deep zonal winds is estimated firstly. The oblate spheroidal shape of an undistorted Jupiter resulting from its fast solid body rotation is fully taken into account, which marks the most significant improvement from previous approximation based Jovian wind theories. High viscosity flows, for example Stokes flows, occur in a lot of processes involving low-speed motions in fluids. Microorganism swimming is such a typical case. A fully three dimensional analytic solution of incompressible Stokes equation is derived in the exterior domain of an arbitrarily translating and rotating prolate spheroid, which models a large family of microorganisms such as cocci bacteria. The solution is then applied to the magnetotactic bacteria swimming problem, and good consistency has been found between theoretical predictions and laboratory observations of the moving patterns of such bacteria under magnetic fields. In the analysis of dynamics of planetary
Analytic model and frequency characteristics of plasma synthetic jet actuator
NASA Astrophysics Data System (ADS)
Zong, Hao-hua; Wu, Yun; Li, Ying-hong; Song, Hui-min; Zhang, Zhi-bo; Jia, Min
2015-02-01
This paper reports a novel analytic model of a plasma synthetic jet actuator (PSJA), considering both the heat transfer effect and the inertia of the throat gas. Both the whole cycle characteristics and the repetitive working process of PSJA can be predicted with this model. The frequency characteristics of a PSJA with 87 mm3 volume and different orifice diameters are investigated based on the analytic model combined with experiments. In the repetitive working mode, the actuator works initially in the transitional stage with 20 cycles and then in the dynamic balanced stage. During the transitional stage, major performance parameters of PSJA experience stepped growth, while during the dynamic balanced stage, these parameters are characterized by periodic variation. With a constant discharge energy of 6.9 mJ, there exists a saturated frequency of 4 kHz/6 kHz for an orifice diameter of 1 mm/1.5 mm, at which the time-averaged total pressure of the pulsed jet reaches a maximum. Between 0.5 mm and 1.5 mm, a larger orifice diameter leads to a higher saturated frequency due to the reduced jet duration time. As the actuation frequency increases, both the time-averaged cavity temperature and the peak jet velocity initially increase and then remain almost unchanged at 1600 K and 280 m/s, respectively. Besides, with increasing frequency, the mechanical energy incorporated in single pulsed jet, the expelled mass per pulse, and the time-averaged density in the cavity, decline in a stair stepping way, which is caused by the intermittent decrease of refresh stage duration in one period.
Semi-analytic approach for electromagnetic problems of large arrays structures
NASA Astrophysics Data System (ADS)
Rostami-Angas, Masoud
There are limited electromagnetic problems which have closed form analytic solutions. Most of the real-world electromagnetic problems like electromagnetic scattering, electromagnetic radiation, waveguide modeling, etc., are not analytically calculable, because of the multitude of irregular geometries found in actual devices. Numerical computational techniques can be used as alternative method to overcome the inability of deriving closed form solutions of Maxwell's equations under various constitutive relations of media, and boundary conditions. This makes computational electromagnetics important in microwave, RF and photonic areas. Care must be taken into choosing the right method; otherwise the wrong method can either yield incorrect results, or results which take excessively long or demand great computational resources. Moreover, there are important electromagnetic problems for which numerical method solutions are challenging, if not impossible. Large non-periodic array of dipoles and multilayer spheres are examples of those problems. Some of these problems, because of their specific geometries and characteristics, can be modeled accurately and efficiently by applying Discrete Dipole Approximation (DDA), multipole expansion and translation addition theorem. The usual solution approach is to model the electromagnetic fields, or other unknowns, using multipole expansions, truncate appropriately the infinite summations, apply the boundary conditions, and then solve the resulting matrix problem by numerical methods. Because the approach contains both of analytic methods and numerical matrix solvers, it can be considered as a semi-analytic approach. The first chapter briefly describes the electromagnetic problems and semi-analytic approaches of this thesis. In the second chapter, a large array of molecular aggregates is investigated with the goal of solving the multiscale problem of a large array of molecules to explore its optical behaviors. Quantum electrodynamics
Asbestos quantification in track ballast, a complex analytical problem
NASA Astrophysics Data System (ADS)
Cavallo, Alessandro
2016-04-01
Track ballast forms the trackbeb upon which railroad ties are laid. It is used to bear the load from the railroad ties, to facilitate water drainage, and also to keep down vegetation. It is typically made of angular crushed stone, with a grain size between 30 and 60 mm, with good mechanical properties (high compressive strength, freeze - thaw resistance, resistance to fragmentation). The most common rock types are represented by basalts, porphyries, orthogneisses, some carbonatic rocks and "green stones" (serpentinites, prasinites, amphibolites, metagabbros). Especially "green stones" may contain traces, and sometimes appreciable amounts of asbestiform minerals (chrysotile and/or fibrous amphiboles, generally tremolite - actinolite). In Italy, the chrysotile asbestos mine in Balangero (Turin) produced over 5 Mt railroad ballast (crushed serpentinites), which was used for the railways in northern and central Italy, from 1930 up to 1990. In addition to Balangero, several other serpentinite and prasinite quarries (e.g. Emilia Romagna) provided the railways ballast up to the year 2000. The legal threshold for asbestos content in track ballast is established in 1000 ppm: if the value is below this threshold, the material can be reused, otherwise it must be disposed of as hazardous waste, with very high costs. The quantitative asbestos determination in rocks is a very complex analytical issue: although techniques like TEM-SAED and micro-Raman are very effective in the identification of asbestos minerals, a quantitative determination on bulk materials is almost impossible or really expensive and time consuming. Another problem is represented by the discrimination of asbestiform minerals (e.g. chrysotile, asbestiform amphiboles) from the common acicular - pseudo-fibrous varieties (lamellar serpentine minerals, prismatic/acicular amphiboles). In this work, more than 200 samples from the main Italian rail yards were characterized by a combined use of XRD and a special SEM
Analytical Solution to the Riemann Problem of Three-Phase Flow in Porous Media
Juanes, Ruben; Patzek, Tadeusz W.
2002-09-26
In this paper we study one-dimensional three-phase flow through porous media of immiscible, incompressible fluids. The model uses the common multiphase flow extension of Darcy's equation, and does not include gravity and capillarity effects. Under these conditions, the mathematical problem reduces to a 2 x 2 system of conservation laws whose essential features are: (1) the system is strictly hyperbolic; (2) both characteristic fields are nongenuinely nonlinear, with single, connected inflection loci. These properties, which are natural extensions of the two-phase flow model, ensure that the solution is physically sensible. We present the complete analytical solution to the Riemann problem (constant initial and injected states) in detail, and describe the characteristic waves that may arise, concluding that only nine combinations of rarefactions, shocks and rarefaction-shocks are possible. We demonstrate that assuming the saturation paths of the solution are straightlines may result in inaccurate predictions for some realistic systems. Efficient algorithms for computing the exact solution are also given, making the analytical developments presented here readily applicable to interpretation of lab displacement experiments, and implementation of streamline simulators.
Kramers problem: numerical Wiener-Hopf-like model characteristics.
Ezin, A N; Samgin, A L
2010-11-01
Since the Kramers problem cannot be, in general, solved in terms of elementary functions, various numerical techniques or approximate methods must be employed. We present a study of characteristics for a particle in a damped well, which can be considered as a discretized version of the Melnikov [Phys. Rev. E 48, 3271 (1993)] turnover theory. The main goal is to justify the direct computational scheme to the basic Wiener-Hopf model. In contrast to the Melnikov approach, which implements factorization through a Cauchy-theorem-based formulation, we employ the Wiener-Levy theorem to reduce the Kramers problem to a Wiener-Hopf sum equation written in terms of Toeplitz matrices. This latter can provide a stringent test for the reliability of analytic approximations for energy distribution functions occurring in the Kramers problems at arbitrary damping. For certain conditions, the simulated characteristics are compared well with those determined using the conventional Fourier-integral formulas, but sometimes may differ slightly depending on the value of a dissipation parameter. Another important feature is that, with our method, we can avoid some complications inherent to the Melnikov method. The calculational technique reported in the present paper may gain particular importance in situations where the energy losses of the particle to the bath are a complex-shaped function of the particle energy and analytic solutions of desired accuracy are not at hand. In order to appreciate more readily the significance and scope of the present numerical approach, we also discuss concrete aspects relating to the field of superionic conductors.
Characteristics of Problems for Problem-Based Learning: The Students' Perspective
ERIC Educational Resources Information Center
Sockalingam, Nachamma; Schmidt, Henk G.
2011-01-01
This study aimed to identify salient problem characteristics perceived by students in problem-based curricula. To this end, reflective essays from biomedical students (N = 34) on characteristics of good problems were text-analyzed. Students identified eleven characteristics, of which they found the extent to which the problem leads to desired…
Nanomaterials in consumer products: a challenging analytical problem
NASA Astrophysics Data System (ADS)
Contado, Catia
2015-08-01
Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits versus risks of engineered nanomaterials and consequently to legislate in favor of consumer’s protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.
Nanomaterials in consumer products: a challenging analytical problem
Contado, Catia
2015-01-01
Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits vs. risks of engineered nanomaterials and consequently to legislate in favor of consumer's protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices. PMID:26301216
Visual Attention Modulates Insight versus Analytic Solving of Verbal Problems
ERIC Educational Resources Information Center
Wegbreit, Ezra; Suzuki, Satoru; Grabowecky, Marcia; Kounios, John; Beeman, Mark
2012-01-01
Behavioral and neuroimaging findings indicate that distinct cognitive and neural processes underlie solving problems with sudden insight. Moreover, people with less focused attention sometimes perform better on tests of insight and creative problem solving. However, it remains unclear whether different states of attention, within individuals,…
Overview of tritium: characteristics, sources, and problems.
Okada, S; Momoshima, N
1993-12-01
Tritium has certain characteristics that present unique challenges for dosimetry and health-risk assessment. For example, in the gas form, tritium can diffuse through almost any container, including those made of steel, aluminum, and plastics. In the oxide form, tritium can generally not be detected by commonly used survey instruments. In the environment, tritium can be taken up by all hydrogen-containing molecules, distributing widely on a global scale. Tritium can be incorporated into humans through respiration, ingestion, and diffusion through skin. Its harmful effects are observed only when it is incorporated into the body. Several sources contribute to the inventory of tritium in our environment. These are 1) cosmic ray interaction with atmospheric molecules; 2) nuclear reactions in the earth's crust; 3) nuclear testing in the atmosphere during the 1950s and 1960s; 4) continuous release of tritium from nuclear power plants and tritium production facilities under normal operation; 5) incidental releases from these facilities; and 6) consumer products. An important future source will be nuclear fusion facilities expected to be developed for the purpose of electricity generation. The principal health physics problems associated with tritium are 1) the determination of the parameters for risk estimation with further reduction of their uncertainties (e.g., relative biological effectiveness and dose-rate dependency); 2) risk estimation from complex exposures to tritium in gas form, tritium in oxide form, tritium surface contamination, and other tritium-contaminated forms, with or without other ionizing radiations and/or nonionizing radiations; 3) the dose contributions of elemental tritium in the lung and from its oxidized tritium in the gastrointestinal tract; 4) prevention of tritium (in oxide form) intake and enhancement of tritium (oxide form) excretion from the human body; 5) precise health effects information for low-level tritium exposure; and 6) public
Features and Characteristics of Problem Based Learning
ERIC Educational Resources Information Center
Ceker, Eser; Ozdamli, Fezile
2016-01-01
Throughout the years, there appears to be an increase in Problem Based Learning applications in education; and Problem Based Learning related research areas. The main aim of this research is to underline the fundamentals (basic elements) of Problem Based Learning, investigate the dimensions of research approached to PBL oriented areas (with a look…
Three-body quantum Coulomb problem: Analytic continuation
NASA Astrophysics Data System (ADS)
Turbiner, A. V.; Lopez Vieyra, J. C.; Olivares Pilón, H.
2016-08-01
The second (unphysical) critical charge in the three-body quantum Coulomb system of a nucleus of positive charge Z and mass mp, and two electrons, predicted by Stillinger has been calculated to be equal to ZB∞ = 0.904854 and ZBmp = 0.905138 for infinite and finite (proton) mass mp, respectively. It is shown that in both cases, the ground state energy E(Z) (analytically continued beyond the first critical charge Zc, for which the ionization energy vanishes, to ReZ
Detecting doping use: more than an analytical problem.
Delanghe, J R; Maenhout, T M; Speeckaert, M M; De Buyzere, M L
2014-01-01
The recent Armstrong case, where more than 250 negative doping tests are confronted with the athlete's confession of erythropoietin use, blood doping, steroid, and growth hormone abuse, illustrates the limitations of current laboratory tests in detecting doping in sport. Despite numerous doping controls and simultaneous indications of common doping abuse among professional athletes in the last two decades, the number of positive urine tests for recombinant human erythropoietin (rHuEPO) remains remarkably low. Athletes are using various masking strategies, among them protease inhibitors, intravenous injections of rHuEPO and alternative erythropoiesis stimulating agents. As one of the countermeasures, the Athlete's Biological Passport has been introduced. The sensitivity of the Athlete's Biological Passport is limited if the effect of a low-dose doping remains within the intra-individual reference range. A possible solution could be the use of a novel Epo test (MAIIA Diagnostics). Another performance-enhancing strategy is the return to 'old' doping techniques, such as autologous blood transfusions. Several indirect methods to detect autologous blood transfusions have been proposed with the majority relying on changes in erythropoiesis-sensitive blood markers. Currently, an algorithm based on the haemoglobin (Hb) level concentration and the percentage of reticulocytes (OFF-hr model; Hb(g/l)-60·√%ret) is approved by the World Anti-Doping Agency. Genetic factors have been identified which may interfere with test interpretation. A large inter- and intra-ethnic variation in testosterone glucuronidation and excretion has been described. Consideration of genetic variation should improve performance of the testosterone doping test. Taking into account the pre-analytical care and better tailoring of the threshold values could increase test sensitivity. Anti-doping laboratories should routinely adjust for multiple testing as failure of doping control to detect cheaters
Trindade, Mariana Teixeira da; Kogawa, Ana Carolina; Salgado, Hérida Regina Nunes
2017-09-11
Diabetes mellitus is considered a public health problem. The initial treatment consists of improving the lifestyle and making changes in the diet. When these changes are not enough, the use of medication becomes necessary. The metformin aims to reduce the hepatic production of glucose and is the preferred treatment for type 2. The objective is to survey the characteristics and properties of metformin, as well as hold a discussion on the existing analytical methods to green chemistry and their impacts for both the operator and the environment. For the survey data searches were conducted by scientific papers in the literature as well as in official compendium. The characteristics and properties are shown, also, methods using liquid chromatography techniques, titration, absorption spectrophotometry in the ultraviolet and the infrared region. Most of the methods presented are not green chemistry oriented. It is necessary the awareness of everyone involved in the optimization of the methods applied through the implementation of green chemistry to determine the metformin.
ERIC Educational Resources Information Center
Cancilla, Devon A.
2001-01-01
Introduces an undergraduate level problem-based analytical chemistry laboratory course integrated with an environmental law course. Aims to develop an understanding among students on the use of environmental indicators for environmental evaluation. (Contains 30 references.) (YDS)
ERIC Educational Resources Information Center
Cancilla, Devon A.
2001-01-01
Introduces an undergraduate level problem-based analytical chemistry laboratory course integrated with an environmental law course. Aims to develop an understanding among students on the use of environmental indicators for environmental evaluation. (Contains 30 references.) (YDS)
Chemometric classification techniques as a tool for solving problems in analytical chemistry.
Bevilacqua, Marta; Nescatelli, Riccardo; Bucci, Remo; Magrì, Andrea D; Magrì, Antonio L; Marini, Federico
2014-01-01
Supervised pattern recognition (classification) techniques, i.e., the family of chemometric methods whose aim is the prediction of a qualitative response on a set of samples, represent a very important assortment of tools for solving problems in several areas of applied analytical chemistry. This paper describes the theory behind the chemometric classification techniques most frequently used in analytical chemistry together with some examples of their application to real-world problems.
An analytic approach to resolving problems in medical ethics.
Candee, D; Puka, B
1984-01-01
Education in ethics among practising professionals should provide a systematic procedure for resolving moral problems. A method for such decision-making is outlined using the two classical orientations in moral philosophy, teleology and deontology. Teleological views such as utilitarianism resolve moral dilemmas by calculating the excess of good over harm expected to be produced by each feasible alternative for action. The deontological view focuses on rights, duties, and principles of justice. Both methods are used to resolve the 1971 Johns Hopkins case of a baby born with Down's syndrome and duodenal atresia. PMID:6234395
Analytical derivation: An epistemic game for solving mathematically based physics problems
NASA Astrophysics Data System (ADS)
Bajracharya, Rabindra R.; Thompson, John R.
2016-06-01
Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the analytical derivation game. This game involves deriving an equation through symbolic manipulations and routine mathematical operations, usually without any physical interpretation of the processes. This game often creates cognitive obstacles in students, preventing them from using alternative resources or better approaches during problem solving. We conducted hour-long, semi-structured, individual interviews with fourteen introductory physics students. Students were asked to solve four "pseudophysics" problems containing algebraic and graphical representations. The problems required the application of the fundamental theorem of calculus (FTC), which is one of the most frequently used mathematical concepts in physics problem solving. We show that the analytical derivation game is necessary, but not sufficient, to solve mathematically based physics problems, specifically those involving graphical representations.
Analytical Derivation: An Epistemic Game for Solving Mathematically Based Physics Problems
ERIC Educational Resources Information Center
Bajracharya, Rabindra R.; Thompson, John R.
2016-01-01
Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the "analytical derivation" game. This game involves deriving an…
ERIC Educational Resources Information Center
Trentacosta, Christopher J.; Fine, Sarah E.
2010-01-01
The present meta-analytic review examined the magnitude of the relation between discrete emotion knowledge and three of its most commonly studied correlates in childhood and adolescence: social competence, internalizing problems, and externalizing problems. Emotion knowledge demonstrated small to medium-sized relations with each correlate.…
Analytical Derivation: An Epistemic Game for Solving Mathematically Based Physics Problems
ERIC Educational Resources Information Center
Bajracharya, Rabindra R.; Thompson, John R.
2016-01-01
Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the "analytical derivation" game. This game involves deriving an…
Characteristics of Early Community College Dropouts. CCRC Analytics
ERIC Educational Resources Information Center
Crosta, Peter M.
2013-01-01
For colleges to develop effective dropout prevention strategies, it is necessary to have a clear picture of who these early dropouts are. This report identifies distinguishing characteristics of this group by analyzing six years of transcript data on 14,429 first-time college students who in 2005 and 2006 enrolled at one of five community colleges…
Li, Yan; Thomas, Manoj; Osei-Bryson, Kweku-Muata; Levy, Jason
2016-01-01
With the growing popularity of data analytics and data science in the field of environmental risk management, a formalized Knowledge Discovery via Data Analytics (KDDA) process that incorporates all applicable analytical techniques for a specific environmental risk management problem is essential. In this emerging field, there is limited research dealing with the use of decision support to elicit environmental risk management (ERM) objectives and identify analytical goals from ERM decision makers. In this paper, we address problem formulation in the ERM understanding phase of the KDDA process. We build a DM3 ontology to capture ERM objectives and to inference analytical goals and associated analytical techniques. A framework to assist decision making in the problem formulation process is developed. It is shown how the ontology-based knowledge system can provide structured guidance to retrieve relevant knowledge during problem formulation. The importance of not only operationalizing the KDDA approach in a real-world environment but also evaluating the effectiveness of the proposed procedure is emphasized. We demonstrate how ontology inferencing may be used to discover analytical goals and techniques by conceptualizing Hazardous Air Pollutants (HAPs) exposure shifts based on a multilevel analysis of the level of urbanization (and related economic activity) and the degree of Socio-Economic Deprivation (SED) at the local neighborhood level. The HAPs case highlights not only the role of complexity in problem formulation but also the need for integrating data from multiple sources and the importance of employing appropriate KDDA modeling techniques. Challenges and opportunities for KDDA are summarized with an emphasis on environmental risk management and HAPs. PMID:27983713
Li, Yan; Thomas, Manoj; Osei-Bryson, Kweku-Muata; Levy, Jason
2016-12-15
With the growing popularity of data analytics and data science in the field of environmental risk management, a formalized Knowledge Discovery via Data Analytics (KDDA) process that incorporates all applicable analytical techniques for a specific environmental risk management problem is essential. In this emerging field, there is limited research dealing with the use of decision support to elicit environmental risk management (ERM) objectives and identify analytical goals from ERM decision makers. In this paper, we address problem formulation in the ERM understanding phase of the KDDA process. We build a DM³ ontology to capture ERM objectives and to inference analytical goals and associated analytical techniques. A framework to assist decision making in the problem formulation process is developed. It is shown how the ontology-based knowledge system can provide structured guidance to retrieve relevant knowledge during problem formulation. The importance of not only operationalizing the KDDA approach in a real-world environment but also evaluating the effectiveness of the proposed procedure is emphasized. We demonstrate how ontology inferencing may be used to discover analytical goals and techniques by conceptualizing Hazardous Air Pollutants (HAPs) exposure shifts based on a multilevel analysis of the level of urbanization (and related economic activity) and the degree of Socio-Economic Deprivation (SED) at the local neighborhood level. The HAPs case highlights not only the role of complexity in problem formulation but also the need for integrating data from multiple sources and the importance of employing appropriate KDDA modeling techniques. Challenges and opportunities for KDDA are summarized with an emphasis on environmental risk management and HAPs.
Solution of prey-predator problem by numeric-analytic technique
NASA Astrophysics Data System (ADS)
Chowdhury, M. S. H.; Hashim, I.; Mawa, S.
2009-04-01
In this paper, an analytical expression for the solution of the prey-predator problem by an adaptation of the classical Adomian decomposition method (ADM). The ADM is treated as an algorithm for approximating the solution of the problem in a sequence of time intervals, i.e. the classical ADM is converted into a hybrid numeric-analytic method called the multistage ADM (MADM). Numerical comparisons with the classical ADM, and the classical fourth-order Rungge-Kutta (RK4) methods are presented.
Analytical treatment of the two-body problem with slowly varying mass
NASA Astrophysics Data System (ADS)
Rahoma, W. A.; Abd El-Salam, F. A.; Ahmed, M. K.
2009-12-01
The present work is concerned with the two-body problem with varying mass in case of isotropic mass loss from both components of the binary systems. The law of mass variation used gives rise to a perturbed Keplerian problem depending on two small parameters. The problem is treated analytically in the Hamiltonian frame-work and the equations of motion are integrated using the Lie series developed and applied, separately by Delva (1984) and Hanslmeier (1984). A second order theory of the two bodies eject mass is constructed, returning the terms of the rate of change of mass up to second order in the small parameters of the problem.
An analytical procedure for evaluating shuttle abort staging aerodynamic characteristics
NASA Technical Reports Server (NTRS)
Meyer, R.
1973-01-01
An engineering analysis and computer code (AERSEP) for predicting Space Shuttle Orbiter - HO Tank longitudinal aerodynamic characteristics during abort separation has been developed. Computed results are applicable at Mach numbers above 2 for angle-of-attack between plus or minus 10 degrees. No practical restrictions on orbiter-tank relative positioning are indicated for tank-under-orbiter configurations. Input data requirements and computer running times are minimal facilitating program use for parametric studies, test planning, and trajectory analysis. In a majority of cases AERSEP Orbiter-Tank interference predictions are as accurate as state-of-the-art estimates for interference-free or isolated-vehicle configurations. AERSEP isolated-orbiter predictions also show excellent correlation with data.
NASA Astrophysics Data System (ADS)
Zingerman, K. M.; Shavyrin, D. A.
2016-06-01
The approximate analytical solution of a quasi-static plane problem of the theory of viscoelasticity is obtained under finite strains. This is the problem of the stress-strain state in an infinite body with circular viscoelastic inclusion. The perturbation technique, Laplace transform, and complex Kolosov-Muskhelishvili's potentials are used for the solution. The numerical results are presented. The nonlinear effects and the effects of viscosity are estimated.
Li, Rui; Wang, Pengcheng; Tian, Yu; Wang, Bo; Li, Gang
2015-01-01
A unified analytic solution approach to both static bending and free vibration problems of rectangular thin plates is demonstrated in this paper, with focus on the application to corner-supported plates. The solution procedure is based on a novel symplectic superposition method, which transforms the problems into the Hamiltonian system and yields accurate enough results via step-by-step rigorous derivation. The main advantage of the developed approach is its wide applicability since no trial solutions are needed in the analysis, which is completely different from the other methods. Numerical examples for both static bending and free vibration plates are presented to validate the developed analytic solutions and to offer new numerical results. The approach is expected to serve as a benchmark analytic approach due to its effectiveness and accuracy. PMID:26608602
Rating Students' Problem Behaviour: The Role of Teachers' Individual Characteristics
ERIC Educational Resources Information Center
Kokkinos, Constantinos M.; Kargiotidis, Apostolos
2016-01-01
This study examined the role of teachers' personal characteristics and mental health status on their frequency ratings of student problem behaviour. A sample of 121 primary school teachers were asked to rate the frequency of a student's behavioural problems, and to self-report their personality traits, psychopathology symptoms and burnout.…
Rating Students' Problem Behaviour: The Role of Teachers' Individual Characteristics
ERIC Educational Resources Information Center
Kokkinos, Constantinos M.; Kargiotidis, Apostolos
2016-01-01
This study examined the role of teachers' personal characteristics and mental health status on their frequency ratings of student problem behaviour. A sample of 121 primary school teachers were asked to rate the frequency of a student's behavioural problems, and to self-report their personality traits, psychopathology symptoms and burnout.…
ERIC Educational Resources Information Center
Wetterneck, Chad T.; Hart, John M.
2012-01-01
Problems with intimacy and interpersonal issues are exhibited across most psychiatric disorders. However, most of the targets in Cognitive Behavioral Therapy are primarily intrapersonal in nature, with few directly involved in interpersonal functioning and effective intimacy. Functional Analytic Psychotherapy (FAP) provides a behavioral basis for…
Impulsive-Analytic Disposition in Mathematical Problem Solving: A Survey and a Mathematics Test
ERIC Educational Resources Information Center
Lim, Kien H.; Wagler, Amy
2012-01-01
The Likelihood-to-Act (LtA) survey and a mathematics test were used in this study to assess students' impulsive-analytic disposition in the context of mathematical problem solving. The results obtained from these two instruments were compared to those obtained using two widely-used scales: Need for Cognition (NFC) and Barratt Impulsivity Scale…
ERIC Educational Resources Information Center
Boyce, Mary C.; Singh, Kuki
2008-01-01
This paper describes a student-focused activity that promotes effective learning in analytical chemistry. Providing an environment where students were responsible for their own learning allowed them to participate at all levels from designing the problem to be addressed, planning the laboratory work to support their learning, to providing evidence…
ERIC Educational Resources Information Center
Boyce, Mary C.; Singh, Kuki
2008-01-01
This paper describes a student-focused activity that promotes effective learning in analytical chemistry. Providing an environment where students were responsible for their own learning allowed them to participate at all levels from designing the problem to be addressed, planning the laboratory work to support their learning, to providing evidence…
New analytical solutions to the two-phase water faucet problem
Zou, Ling; Zhao, Haihua; Zhang, Hongbin
2016-06-17
Here, the one-dimensional water faucet problem is one of the classical benchmark problems originally proposed by Ransom to study the two-fluid two-phase flow model. With certain simplifications, such as massless gas phase and no wall and interfacial frictions, analytical solutions had been previously obtained for the transient liquid velocity and void fraction distribution. The water faucet problem and its analytical solutions have been widely used for the purposes of code assessment, benchmark and numerical verifications. In our previous study, the Ransom’s solutions were used for the mesh convergence study of a high-resolution spatial discretization scheme. It was found that, atmore » the steady state, an anticipated second-order spatial accuracy could not be achieved, when compared to the existing Ransom’s analytical solutions. A further investigation showed that the existing analytical solutions do not actually satisfy the commonly used two-fluid single-pressure two-phase flow equations. In this work, we present a new set of analytical solutions of the water faucet problem at the steady state, considering the gas phase density’s effect on pressure distribution. This new set of analytical solutions are used for mesh convergence studies, from which anticipated second-order of accuracy is achieved for the 2nd order spatial discretization scheme. In addition, extended Ransom’s transient solutions for the gas phase velocity and pressure are derived, with the assumption of decoupled liquid and gas pressures. Numerical verifications on the extended Ransom’s solutions are also presented.« less
New analytical solutions to the two-phase water faucet problem
Zou, Ling; Zhao, Haihua; Zhang, Hongbin
2016-06-17
Here, the one-dimensional water faucet problem is one of the classical benchmark problems originally proposed by Ransom to study the two-fluid two-phase flow model. With certain simplifications, such as massless gas phase and no wall and interfacial frictions, analytical solutions had been previously obtained for the transient liquid velocity and void fraction distribution. The water faucet problem and its analytical solutions have been widely used for the purposes of code assessment, benchmark and numerical verifications. In our previous study, the Ransom’s solutions were used for the mesh convergence study of a high-resolution spatial discretization scheme. It was found that, at the steady state, an anticipated second-order spatial accuracy could not be achieved, when compared to the existing Ransom’s analytical solutions. A further investigation showed that the existing analytical solutions do not actually satisfy the commonly used two-fluid single-pressure two-phase flow equations. In this work, we present a new set of analytical solutions of the water faucet problem at the steady state, considering the gas phase density’s effect on pressure distribution. This new set of analytical solutions are used for mesh convergence studies, from which anticipated second-order of accuracy is achieved for the 2nd order spatial discretization scheme. In addition, extended Ransom’s transient solutions for the gas phase velocity and pressure are derived, with the assumption of decoupled liquid and gas pressures. Numerical verifications on the extended Ransom’s solutions are also presented.
NASA Astrophysics Data System (ADS)
Zou, Li; Liang, Songxin; Li, Yawei; Jeffrey, David J.
2017-03-01
Nonlinear boundary value problems arise frequently in physical and mechanical sciences. An effective analytic approach with two parameters is first proposed for solving nonlinear boundary value problems. It is demonstrated that solutions given by the two-parameter method are more accurate than solutions given by the Adomian decomposition method (ADM). It is further demonstrated that solutions given by the ADM can also be recovered from the solutions given by the two-parameter method. The effectiveness of this method is demonstrated by solving some nonlinear boundary value problems modeling beam-type nano-electromechanical systems.
New Tools to Prepare ACE Cross-section Files for MCNP Analytic Test Problems
Brown, Forrest B.
2016-06-17
Monte Carlo calculations using one-group cross sections, multigroup cross sections, or simple continuous energy cross sections are often used to: (1) verify production codes against known analytical solutions, (2) verify new methods and algorithms that do not involve detailed collision physics, (3) compare Monte Carlo calculation methods with deterministic methods, and (4) teach fundamentals to students. In this work we describe 2 new tools for preparing the ACE cross-section files to be used by MCNP^{®} for these analytic test problems, simple_ace.pl and simple_ace_mg.pl.
Semi-analytical method for solving nonlinear heat diffusion problems in spherical medium
NASA Astrophysics Data System (ADS)
Abd-El-Malek, Mina B.; Helal, Medhat M.
2006-08-01
A semi-analytical methodology, based on the finite integral transform technique, is proposed to solve the heat diffusion problem in a spherical medium subject to nonlinear boundary conditions due to radiation exchange at the interface according to the fourth power law. The method proceeds by treating the nonlinearity term in the boundary condition as a source in the differential equation and keeping other conditions unchanged. The results obtained from this semi-analytical solutions are compared with those obtained from a numerical solution developed using an explicit finite difference method, which showed very good agreement.
Fast and accurate analytical model to solve inverse problem in SHM using Lamb wave propagation
NASA Astrophysics Data System (ADS)
Poddar, Banibrata; Giurgiutiu, Victor
2016-04-01
Lamb wave propagation is at the center of attention of researchers for structural health monitoring of thin walled structures. This is due to the fact that Lamb wave modes are natural modes of wave propagation in these structures with long travel distances and without much attenuation. This brings the prospect of monitoring large structure with few sensors/actuators. However the problem of damage detection and identification is an "inverse problem" where we do not have the luxury to know the exact mathematical model of the system. On top of that the problem is more challenging due to the confounding factors of statistical variation of the material and geometric properties. Typically this problem may also be ill posed. Due to all these complexities the direct solution of the problem of damage detection and identification in SHM is impossible. Therefore an indirect method using the solution of the "forward problem" is popular for solving the "inverse problem". This requires a fast forward problem solver. Due to the complexities involved with the forward problem of scattering of Lamb waves from damages researchers rely primarily on numerical techniques such as FEM, BEM, etc. But these methods are slow and practically impossible to be used in structural health monitoring. We have developed a fast and accurate analytical forward problem solver for this purpose. This solver, CMEP (complex modes expansion and vector projection), can simulate scattering of Lamb waves from all types of damages in thin walled structures fast and accurately to assist the inverse problem solver.
Analytical stability criteria for the Caledonian Symmetric Four and Five Body Problems
NASA Astrophysics Data System (ADS)
Steves, Bonnie; Shoaib Afridi, Mohammad; Sweatman, Winston
2017-06-01
Analytical studies of the stability of three or more body gravitational systems are difficult because of the greater number of variables involved with the increasing number of bodies and the limitation of 10 integrals that exist in the gravitational n-body problem. Utilisation of symmetries or the neglecting of the masses of some of the bodies compared to others can simplify the dynamical problem and enable global analytical stability solutions to be derived. These symmetric and restricted few body systems with their analytical stability criterion can then provide useful information on the stability of the general few body system when near symmetry or the restricted situation. Even with symmetrical reductions, analytical stability derivations for four and five body problems are rare. In this paper, we develop an analytical stability criterion for the Caledonian Symmetric Five Body Problem (CS5BP) , a dynamically symmetrical planar problem with two pairs of equal masses and a fifth mass located at the centre of mass. Sundman’s inequality is applied to derive boundary surfaces to the allowed real motion of the system. This enables the derivation of a stability criterion valid for all time for the hierarchical stability of the CS5BP and its subset the Caledonian Symmetric Four Body Problem (CSFBP), where the central mass is taken to be equal to zero. We show that the hierarchical stability depends solely on the Szebehely constant C0, which is a function of the total energy H and angular momentum c. The critical value Ccrit at which the system becomes hierarchically stable for all time depends only on the two mass ratios of the symmetric five body system. We then explore the effect on the stability of the whole system of adding an increasing massive central body. It is shown both analytically and numerically that all CS5BPs and CSFBPs of different mass ratios are hierarchically stable if C0 > 0.0659 and C0 > 0.0465, respectively. The Caledonian Symmetric Four and
NASA Astrophysics Data System (ADS)
Toro, Eleuterio F.; Montecinos, Gino I.
2015-12-01
We present a semi-analytical, implicit solution to the generalized Riemann problem (GRP) for non-linear systems of hyperbolic balance laws with stiff source terms. The solution method is based on an implicit, time Taylor series expansion and the Cauchy-Kowalewskaya procedure, along with the solution of a sequence of classical Riemann problems. Our new GRP solver is then used to construct locally implicit ADER methods of arbitrary accuracy in space and time for solving the general initial-boundary value problem for non-linear systems of hyperbolic balance laws with stiff source terms. Analysis of the method for model problems is carried out and empirical convergence rate studies for suitable tests problems are performed, confirming the theoretically expected high order of accuracy.
Relations Between Toddler Sleep Characteristics, Sleep Problems, and Temperament.
Molfese, Victoria J; Rudasill, Kathleen M; Prokasky, Amanda; Champagne, Carly; Holmes, Molly; Molfese, Dennis L; Bates, John E
2015-01-01
Two sources of information (parent-reported sleep diaries and actigraph records) were used to investigate how toddler sleep characteristics (bed time/sleep onset, wake time/sleep offset, total nighttime sleep, and total sleep time) are related to sleep problems and temperament. There were 64 toddler participants in the study. Consistent with studies of older children, parent reports differed from actigraph-based records. The findings that parent-reported and actigraph-recorded sleep characteristics varied as a function of parent report of toddler sleep problems and temperament add needed information on toddler sleep. Such information may contribute to improving parents' awareness of their child's sleep characteristics and correlates of problem sleep.
An analytic solution to the Förster energy transfer problem in two dimensions.
Wolber, P K; Hudson, B S
1979-01-01
An analytic solution of the Förster energy transfer problem in two dimensions is presented for the case in which the orientation factor is independent of the donor-acceptor distance, and both the donors and acceptors are randomly distributed in a plane. A general solution based on the method of Förster is possible since all distances are measured in units of R0. The analytic solution is extended to the cases of donors embedded in structures that exclude acceptors, and donors that bind acceptors. The validity of the analytic solutions is demonstrated by comparison with numerical simulation calculations. Numerical approximations to the exact solutions are given for ease of computation. Specific applications to the case of fluorescence quenching of a membrane-bound donor by membrane-bound acceptors are presented. PMID:262548
An analytically iterative method for solving problems of cosmic-ray modulation
NASA Astrophysics Data System (ADS)
Kolesnyk, Yuriy L.; Bobik, Pavol; Shakhov, Boris A.; Putis, Marian
2017-09-01
The development of an analytically iterative method for solving steady-state as well as unsteady-state problems of cosmic-ray (CR) modulation is proposed. Iterations for obtaining the solutions are constructed for the spherically symmetric form of the CR propagation equation. The main solution of the considered problem consists of the zero-order solution that is obtained during the initial iteration and amendments that may be obtained by subsequent iterations. The finding of the zero-order solution is based on the CR isotropy during propagation in the space, whereas the anisotropy is taken into account when finding the next amendments. To begin with, the method is applied to solve the problem of CR modulation where the diffusion coefficient κ and the solar wind speed u are constants with an Local Interstellar Spectra (LIS) spectrum. The solution obtained with two iterations was compared with an analytical solution and with numerical solutions. Finally, solutions that have only one iteration for two problems of CR modulation with u = constant and the same form of LIS spectrum were obtained and tested against numerical solutions. For the first problem, κ is proportional to the momentum of the particle p, so it has the form κ = k0η, where η =p/m_0c. For the second problem, the diffusion coefficient is given in the form κ = k0βη, where β =v/c is the particle speed relative to the speed of light. There was a good matching of the obtained solutions with the numerical solutions as well as with the analytical solution for the problem where κ = constant.
Constructive-analytical solution of the problem of the secular evolution of polar satellite orbits
NASA Astrophysics Data System (ADS)
Vashkov'yak, M. A.
2017-07-01
The well-known twice-averaged Hill problem is considered by taking into account the oblateness of the central body. This problem has several integrable cases that have been studied qualitatively by many scientists, beginning with M.L. Lidov and Y. Kozai. However, no rigorous analytical solution can be obtained in these cases due to the complexity of the integrals. This paper is devoted to studying the case where the equatorial plane of the central body coincides with the plane of its orbital motion relative to the perturbing body, while the satellite itself moves in a polar orbit. A more detailed qualitative study is performed, and an approximate constructive-analytical solution of the evolution system in the form of explicit time dependences of the eccentricity and pericenter argument of the satellite orbit is proposed. The methodical accuracy for the polar orbits of lunar satellites has been estimated by comparison with the numerical solution of the system.
A multigroup radiation diffusion test problem: Comparison of code results with analytic solution
Shestakov, A I; Harte, J A; Bolstad, J H; Offner, S R
2006-12-21
We consider a 1D, slab-symmetric test problem for the multigroup radiation diffusion and matter energy balance equations. The test simulates diffusion of energy from a hot central region. Opacities vary with the cube of the frequency and radiation emission is given by a Wien spectrum. We compare results from two LLNL codes, Raptor and Lasnex, with tabular data that define the analytic solution.
An investigation into some problems in analytical processing of lunar orbiter photography
NASA Technical Reports Server (NTRS)
Ghosh, S. K.; Ekenobi, S.
1972-01-01
Problems in analytical processing of lunar orbiter photography are discussed. The effects of image motion and image motion compensation on the location of the principal point are analyzed. The effect of the focal plane shutter on the distortion and interior geometry is examined. Real data is used to confirm the workability of a mathematical model and the use of a computer to calibrate spaceborne photographic imagery.
Analytical two-dimensional model of solar cell current-voltage characteristics
NASA Astrophysics Data System (ADS)
Caldararu, F.; Caldararu, M.; Nan, S.; Nicolaescu, D.; Vasile, S.
1991-06-01
This paper describes an analytical two-dimensional model for pn junction solar cell I-V characteristic. In order to solve the two-dimensional equations for the minority carrier concentration the Laplace transformation method is used. The model eliminates Hovel's assumptions concerning a one-dimensional model and provides an I-V characteristic that is simpler than those derived from the one-dimensional model. The method can be extended to any other device with two-dimensional symmetry.
Trajectory design using approximate analytic solutions of the N-body problem
NASA Astrophysics Data System (ADS)
Benavides, Julio Cesar
The N-body problem as formulated by Sir Isaac Newton in the seventeenth century has been a rich source of mathematical and scientific discovery. Continuous attempts invested into the solution of this problem over the years have resulted in a host of remarkable theories that have changed the way the world is viewed and analyzed. A final solution in terms of an infinite time-dependent power series was finally discovered in the latter part of the twentieth century. However, the slow convergence of this result makes its implementation impractical in every day spacecraft trajectory design and optimization. The only feasible way to solve the N-body problem reliably is to numerically integrate the equations of motion. This dissertation derives two new variable time step algorithms using time dependent power series solutions developed for the two-body problem. These power series solutions allow the space-dependent N-body problem to be transformed into a time-dependent system of equations that can be solved analytically. The analytic results do not yield global solutions, but rather approximate outcomes whose order of accuracy can be controlled by the user. The two algorithms are used to investigate scenarios corresponding to a highly elliptical orbit in the two-body problem; periodic, central configuration scenarios in the three-body problem; and a non-periodic scenario in the restricted three-body problem. The results obtained are compared to the outcomes returned by a variable time step fourth-order, fifth-order Runge-Kutta numerical integration algorithm. The outcomes derived for each situation demonstrate that the two new variable time step algorithms are both more accurate and much more efficient than their Runge-Kutta counterpart.
NASA Astrophysics Data System (ADS)
Lau, Chun Sing
This thesis studies two types of problems in financial derivatives pricing. The first type is the free boundary problem, which can be formulated as a partial differential equation (PDE) subject to a set of free boundary condition. Although the functional form of the free boundary condition is given explicitly, the location of the free boundary is unknown and can only be determined implicitly by imposing continuity conditions on the solution. Two specific problems are studied in details, namely the valuation of fixed-rate mortgages and CEV American options. The second type is the multi-dimensional problem, which involves multiple correlated stochastic variables and their governing PDE. One typical problem we focus on is the valuation of basket-spread options, whose underlying asset prices are driven by correlated geometric Brownian motions (GBMs). Analytic approximate solutions are derived for each of these three problems. For each of the two free boundary problems, we propose a parametric moving boundary to approximate the unknown free boundary, so that the original problem transforms into a moving boundary problem which can be solved analytically. The governing parameter of the moving boundary is determined by imposing the first derivative continuity condition on the solution. The analytic form of the solution allows the price and the hedging parameters to be computed very efficiently. When compared against the benchmark finite-difference method, the computational time is significantly reduced without compromising the accuracy. The multi-stage scheme further allows the approximate results to systematically converge to the benchmark results as one recasts the moving boundary into a piecewise smooth continuous function. For the multi-dimensional problem, we generalize the Kirk (1995) approximate two-asset spread option formula to the case of multi-asset basket-spread option. Since the final formula is in closed form, all the hedging parameters can also be derived in
Client Engagement Characteristics Associated with Problem Gambling Treatment Outcomes
ERIC Educational Resources Information Center
Dowling, Nicki A.; Cosic, Sanja
2011-01-01
Previous research examining the factors associated with problem gambling treatment outcomes has examined client factors and to date, treatment characteristics, therapist factors, and client-therapist interactions have essentially remained unexplored. This study aimed to investigate how client engagement variables (client-rated therapeutic…
Problem Gambling in Chinese American Adolescents: Characteristics and Risk Factors
ERIC Educational Resources Information Center
Chiu, Eddie Yu-Wai; Woo, Kent
2012-01-01
This preliminary study examined the characteristics and risk factors of problem gambling among Chinese American adolescents. A total of 192 Chinese American students (aged 13-19) from 9th to 12th grades were recruited from three high schools in San Francisco, California. Students were administered the South Oaks Gambling Screen Revised for…
Problem Gambling in Chinese American Adolescents: Characteristics and Risk Factors
ERIC Educational Resources Information Center
Chiu, Eddie Yu-Wai; Woo, Kent
2012-01-01
This preliminary study examined the characteristics and risk factors of problem gambling among Chinese American adolescents. A total of 192 Chinese American students (aged 13-19) from 9th to 12th grades were recruited from three high schools in San Francisco, California. Students were administered the South Oaks Gambling Screen Revised for…
Client Engagement Characteristics Associated with Problem Gambling Treatment Outcomes
ERIC Educational Resources Information Center
Dowling, Nicki A.; Cosic, Sanja
2011-01-01
Previous research examining the factors associated with problem gambling treatment outcomes has examined client factors and to date, treatment characteristics, therapist factors, and client-therapist interactions have essentially remained unexplored. This study aimed to investigate how client engagement variables (client-rated therapeutic…
A Multilevel Analysis of Problem-Based Learning Design Characteristics
ERIC Educational Resources Information Center
Scott, Kimberly S.
2014-01-01
The increasing use of experience-centered approaches like problem-based learning (PBL) by learning and development practitioners and management educators has raised interest in how to design, implement and evaluate PBL in that field. Of particular interest is how to evaluate the relative impact of design characteristics that exist at the…
A Multilevel Analysis of Problem-Based Learning Design Characteristics
ERIC Educational Resources Information Center
Scott, Kimberly S.
2014-01-01
The increasing use of experience-centered approaches like problem-based learning (PBL) by learning and development practitioners and management educators has raised interest in how to design, implement and evaluate PBL in that field. Of particular interest is how to evaluate the relative impact of design characteristics that exist at the…
NASA Astrophysics Data System (ADS)
Konovalov, Aleksandr B.; Vlasov, V. V.; Kalintsev, A. G.; Kravtsenyuk, Olga V.; Lyubimov, Vladimir V.
2006-11-01
The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions.
NASA Technical Reports Server (NTRS)
Eberle, W. R.
1981-01-01
A computer program to calculate the wake downwind of a wind turbine was developed. Turbine wake characteristics are useful for determining optimum arrays for wind turbine farms. The analytical model is based on the characteristics of a turbulent coflowing jet with modification for the effects of atmospheric turbulence. The program calculates overall wake characteristics, wind profiles, and power recovery for a wind turbine directly in the wake of another turbine, as functions of distance downwind of the turbine. The calculation procedure is described in detail, and sample results are presented to illustrate the general behavior of the wake and the effects of principal input parameters.
Analytical solution of the problem of the rise of a Taylor bubble
NASA Astrophysics Data System (ADS)
Zudin, Yuri B.
2013-05-01
In the classical works of Prandtl and Taylor devoted to the analysis of the problem of the rise of a Taylor bubble in a round tube, a solution of the Laplace equation is used, which contains divergent infinite series. The present paper outlines a method for the correct analysis of the mentioned problem. Using the method of superposition of "elementary flows," a solution was obtained for flow of an ideal fluid over a body of revolution in a pipe. Satisfying the free surface condition in the vicinity of the stagnation point and using the limiting transition with respect to the main parameter lead to the relation for the rise velocity of a Taylor bubble expressed in terms of the Froude number. In order to validate the method of superposition, it was applied to the problem of the rise of a plane Taylor bubble in a flat gap, which also has an exact analytical solution obtained with the help of the complex variable theory.
Statistical Mechanics of a Simplified Bipartite Matching Problem: An Analytical Treatment
NASA Astrophysics Data System (ADS)
Dell'Erba, Matías Germán
2012-03-01
We perform an analytical study of a simplified bipartite matching problem in which there exists a constant matching energy, and both heterosexual and homosexual pairings are allowed. We obtain the partition function in a closed analytical form and we calculate the corresponding thermodynamic functions of this model. We conclude that the model is favored at high temperatures, for which the probabilities of heterosexual and homosexual pairs tend to become equal. In the limits of low and high temperatures, the system is extensive, however this property is lost in the general case. There exists a relation between the matching energies for which the system becomes more stable under external (thermal) perturbations. As the difference of energies between the two possible matches increases the system becomes more ordered, while the maximum of entropy is achieved when these energies are equal. In this limit, there is a first order phase transition between two phases with constant entropy.
Fast multigrid solution of the advection problem with closed characteristics
Yavneh, I.; Venner, C.H.; Brandt, A.
1996-12-31
The numerical solution of the advection-diffusion problem in the inviscid limit with closed characteristics is studied as a prelude to an efficient high Reynolds-number flow solver. It is demonstrated by a heuristic analysis and numerical calculations that using upstream discretization with downstream relaxation-ordering and appropriate residual weighting in a simple multigrid V cycle produces an efficient solution process. We also derive upstream finite-difference approximations to the advection operator, whose truncation terms approximate {open_quotes}physical{close_quotes} (Laplacian) viscosity, thus avoiding spurious solutions to the homogeneous problem when the artificial diffusivity dominates the physical viscosity.
Dolgikh, T I
2009-08-01
In the organization of a present-day laboratory, there are 8 fundamental elements that provide its activity and are integrated into the uniform system: safety; the correct organization of work; the range of studies; a current material-and-technical basis; the metrological provision of diagnostic and analytical processes; manpower; and adequate sanitary-and-hygienic and antiepidemic measures. The problems of the laboratory's activity are outlined in the light of implementation of Federal Law on the Uniformity of Measurements under No. 102 - dated June 26, 2008, and ways of their solution are proposed.
Psychological Characteristics of Problem Gamblers With and Without Mood Disorder
Lister, Jamey J; Milosevic, Aleks; Ledgerwood, David M
2015-01-01
Objective: Problem and pathological gamblers are significantly more likely to experience mood disorders, compared with the general population. Our study examined the relation of psychological characteristics (personality, trait impulsiveness, and gambling motives) to current co-occurring mood disorder (major depression and dysthymia) status among problem and pathological gamblers. Method: Problem and pathological gamblers (N = 150) underwent a clinical interview to assess current co-occurring mood disorders; participants completed measures of problem gambling severity, personality, impulsiveness, and gambling motives. Results: Problem and pathological gamblers with a current co-occurring mood disorder were more likely to be female, older, and to report higher lifetime and past-year gambling severity. A co-occurring mood disorder was associated with higher personality scores for alienation and stress reaction, lower scores for well-being, social closeness, and control, as well as higher impulsiveness scores for urgency and lack of premeditation, and lower sensation seeking scores. Participants with a co-occurring mood disorder also reported higher coping motives for gambling. Multivariate logistic regression analyses demonstrated that personality factors (lower social closeness and higher alienation) contributed to the greatest likelihood of being diagnosed with a co-occurring mood disorder. Conclusions: Mood disorders frequently co-occur with problem and pathological gambling, and they are associated with greater gambling severity. These findings highlight that interpersonal facets of personality contribute substantially to co-occurring mood disorder status. Implications for treatment will be discussed. PMID:26454559
NASA Astrophysics Data System (ADS)
Schulreich, M. M.; Breitschwerdt, D.
2011-07-01
Aims: Bow shock waves are a common feature of groups and clusters of galaxies since they are generated as a result of supersonic motion of galaxies through the intergalactic medium. The goal of this work is to present an analytical solution technique for such astrophysical hypersonic blunt body problems. Methods: A method, developed by Schneider (1968, JFM, 31, 397) in the context of aeronautics, allows calculation of the galaxy's shape as long as the shape of the bow shock wave is known (so-called inverse method). In contrast to other analytical models, the solution is valid in the whole flow region (from the stagnation point up to the bow shock wings) and in particular takes into account velocity gradients along the streamlines. We compare our analytical results with two-dimensional hydrodynamical simulations carried out with an extended version of the VH-1 hydrocode which is based on the piecewise parabolic method with a Lagrangian remap. Results: It is shown that the applied method accurately predicts the galaxy's shape and the fluid variables in the post-shock flow, thus saving a tremendous amount of computing time for future interpretations of similar objects. We also find that the method can be applied to arbitrary angles between the direction of the incoming flow and the axis of symmetry of the body. We emphasize that it is general enough to be applied to other astrophysical bow shocks, such as those on stellar and galactic scales.
Hybrid numerical and analytical solutions for acoustic boundary problems in thermo-viscous fluids
NASA Astrophysics Data System (ADS)
Bossart, R.; Joly, N.; Bruneau, M.
2003-05-01
The present work aims at contributing to the investigation of methods to solve some classes of problems of acoustic propagation in thermo-viscous fluids, in unbounded or bounded media. The focus here is on thermal and vortical diffusion at the boundaries, which have to be considered for an accurate description of the acoustic field in small fluid-filled cavities and ducts. Existing boundary element or finite element acoustic software does not include these phenomena, as they are not compatible with the basic equations involved. A methodology is given to solve such problems when using this software, introducing a hybrid method which combines both numerical solutions and analytical solutions (for the fields inside the boundary layers). A detailed application is presented to validate the process using a boundary elements method.
ERIC Educational Resources Information Center
Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, A. L.
2014-01-01
The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking…
ERIC Educational Resources Information Center
Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, A. L.
2014-01-01
The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking…
Comer, Jonathan S.; Chow, Candice; Chan, Priscilla T.; Cooper-Vince, Christine; Wilson, Lianna A.S.
2012-01-01
Objective Service use trends showing increased off-label prescribing in very young children and reduced psychotherapy use raise concerns about quality of care for early disruptive behavior problems. Meta-analysis can empirically clarify best practices and guide clinical decision making by providing a quantitative synthesis of a body of literature, identifying the magnitude of overall effects across studies, and determining systematic factors associated with effect variations. Method We used random-effects meta-analytic procedures to empirically evaluate the overall effect of psychosocial treatments on early disruptive behavior problems, as well as potential moderators of treatment response. Thirty-six controlled trials, evaluating 3,042 children, met selection criteria (mean sample age, 4.7 years; 72.0% male; 33.1% minority youth). Results Psychosocial treatments collectively demonstrated a large and sustained effect on early disruptive behavior problems (Hedges’ g = 0.82), with the largest effects associated with behavioral treatments (Hedges’ g = 0.88), samples with higher proportions of older and male youth, and comparisons against treatment as usual (Hedges’ g = 1.17). Across trials, effects were largest for general externalizing problems (Hedges’ g =0.90) and problems of oppositionality and noncompliance (Hedges’ g = 0.76), and were weakest, relatively speaking, for problems of impulsivity and hyperactivity (Hedges’ g = 0.61). Conclusions In the absence of controlled trials evaluating psychotropic interventions, findings provide robust quantitative support that psychosocial treatments should constitute first-line treatment for early disruptive behavior problems. Against a backdrop of concerning trends in the availability and use of supported interventions, findings underscore the urgency of improving dissemination efforts for supported psychosocial treatment options, and removing systematic barriers to psychosocial care for affected youth. PMID
Analytical Study of Periodic Solutions on Perturbed Equatorial Two-Body Problem
NASA Astrophysics Data System (ADS)
Abouelmagd, Elbaz I.; Mortari, Daniele; Selim, Hadia H.
2015-12-01
This paper presents analytical derivations to study periodic solutions for the two-body problem perturbed by the first zonal harmonic parameter. In particular, three different semianalytical approaches to solve this problem have been studied: (1) the classic perturbation theory, (2) the Lindstedt-Poincaré technique, and (3) the Krylov-Bogoliubov-Mitropolsky method. In addition, the numerical integration by Runge-Kutta algorithm is established. However, the numerical comparison tests show that by increasing the value of angular momentum the solutions provided by Lindstedt-Poincaré and Krylov-Bogoliubov-Mitropolsky methods become similar, and they provide almost identical results using a smaller value for the perturbed parameter which quantify the dynamical flattening of the main body, the Krylov-Bogoliubov-Mitropolsky provides more accurate results to design elliptical periodic solutions than Lindstedt-Poincaré technique when the perturbed parameter has a relatively large value, regardless of the value of angular momentum. This study can be applied to equatorial orbits to obtain closed-form analytical solutions.
Estimation of the smallest eigenvalue in fractional escape problems: Semi-analytics and fits
NASA Astrophysics Data System (ADS)
Dybiec, Bartłomiej; Sokolov, Igor M.
2015-02-01
Continuous time random walks with heavy tailed distributions of waiting times and jump lengths lead to situations when evolution of a probability density of finding a particle at given point at given time is described by the bi-fractional Smoluchowski-Fokker-Planck equation. A power-law distribution of waiting times results in very general properties of a survival probability which in turn can be used to estimate eigenvalues of some fractional operators. Here, the problem of numerical estimation of the smallest eigenvalues is discussed for the two generic problems: escape from a finite interval and the Kramers problem of escape from a potential well. We discuss both how to numerically obtain the (effective) smallest eigenvalue of the problem, and how it can be used in numerically assessing other important characteristics of the processes.
NASA Astrophysics Data System (ADS)
Broman, Karolina; Bernholt, Sascha; Parchmann, Ilka
2015-05-01
found successful to analyse both the test items as well as students' responses in a systematic way. The framework can therefore be applied in the design of new tasks, the analysis and assessment of students' responses, and as a tool for teachers to scaffold students in their problem-solving process. Conclusions:This paper gives implications for practice and for future research to both develop new context-based problems in a structured way, as well as providing analytical tools for investigating students' higher order thinking in their responses to these tasks.
On the location selection problem using analytic hierarchy process and multi-choice goal programming
NASA Astrophysics Data System (ADS)
Ho, Hui-Ping; Chang, Ching-Ter; Ku, Cheng-Yuan
2013-01-01
Location selection is a crucial decision in cost/benefit analysis of restaurants, coffee shops and others. However, it is difficult to be solved because there are many conflicting multiple goals in the problem of location selection. In order to solve the problem, this study integrates analytic hierarchy process (AHP) and multi-choice goal programming (MCGP) as a decision aid to obtain an appropriate house from many alternative locations that better suit the preferences of renters under their needs. This study obtains weights from AHP and implements it upon each goal using MCGP for the location selection problem. According to the function of multi-aspiration provided by MCGP, decision makers can set multi-aspiration for each location goal to rank the candidate locations. Compared to the unaided selection processes, the integrated approach of AHP and MCGP is a better scientific and efficient method than traditional methods in finding a suitable location for buying or renting a house for business, especially under multiple qualitative and quantitative criteria within a shorter evaluation time. In addition, a real case is provided to demonstrate the usefulness of the proposed method. The results show that the proposed method is able to provide better quality decision than normal manual methods.
Smith, Douglas R; Moy, Marie A; Dolan, Anthony R; Wood, Troy D
2006-04-01
As miniaturization of electrospray continues to become more prevalent in the mass spectrometry arsenal, numerous types of conductive coatings have been developed with miniaturized electrospray emitters. Different conductive coatings have different properties that may lead to differences in analytical performance. This paper investigates and compares the analytical properties of a series of applied conductive coatings for low-flow electrospray ionization developed in this laboratory vs. commercially-available types. Evaporated graphite is thoroughly compared with commercially available polyaniline (PANI) coated emitters and metal coated emitters. Each set of emitters was investigated to determine various performance characteristics, including susceptibility to electrical discharge in both positive and negative ionization modes, as well as emitter reproducibility and generation of a standard curve to determine each emitter coating's limit of detection and limit of quantitation. Furthermore, evaporated graphite and polyaniline coated fused silica capillaries were investigated to determine which coating is more stable over long-term analyses and during electrical discharge.
Analytical beam-width characteristics of distorted cat-eye reflected beam
NASA Astrophysics Data System (ADS)
Zhao, Yanzhong; Shan, Congmiao; Zheng, Yonghui; Zhang, Laixian; Sun, Huayan
2015-02-01
The analytical expression of beam-width of distorted cat-eye reflected beam under far-field condition is deduced using the approximate three-dimensional analytical formula for oblique detection laser beam passing through cat-eye optical lens with center shelter, and using the definition of second order moment, Gamma function and integral functions. The laws the variation of divergence angle and astigmatism degree of the reflected light with incident angle, focal shift, aperture size, and center shelter ratio are established by numerical calculation, and physical analysis. The study revealed that the cat-eye reflected beam is like a beam transmitted and collimated by the target optical lens, and has the same characteristics as that of Gaussian beam. A proper choice of positive focal shift would result in a divergence angle smaller than that of no focal shift. The astigmatism is mainly caused by incidence angle.
Analytical solutions and numerical modeling for a dam-break problem in inclined channels
NASA Astrophysics Data System (ADS)
Pelinovsky, Efim; Didenkulova, Ira; Didenkulov, Oleg; Rodin, Artem
2016-04-01
Here we obtain different analytical solutions of the shallow-water equations for inviscid nonlinear waves in inclined channels. (i) The first solution describes Riemann wave moving up or down alone the channel slope. It requires the initial fluid flow, which often accompanies waves generated by landslides. This solution is valid for a finite time before the wave breaks. (ii) The second solution generalizes the classical dam-break problem for the case of a dam located in the inclined channel. In this case the cross-section of the channel influences the speed of wave propagation inside the channel, and therefore changes wave dynamics inside the channel compare to the plane beach. (iii) The third solution describes the intermediate stage of the wave front dynamics for a dam of a large height. This solution is derived with the use of generalized Carrier-Greenspan approach developed early by Didenkulova & Pelinovsky (2011) and Rybkin et al (2014). Some of the analytical solutions are tested with the means of numerical modeling. The numerical modeling is carried out using the CLAWPACK software based on nonlinear shallow water equations. Application of the described solutions to possible laboratory experiments is discussed.
NASA Astrophysics Data System (ADS)
Cancilla, Devon A.
2001-12-01
Environmental chemists face difficult challenges related to generating, interpreting, and communicating complex chemical data in a manner understandable by nonchemists. For this reason, it is essential that environmental chemistry students develop the skills necessary not only to collect and interpret complex data sets, but also to communicate their findings in a credible manner in nonscientific forums. Key to this requirement is an understanding of the quality assurance/quality control (QA/QC) elements used to support specific findings. This paper describes the development of a problem-based undergraduate environmental analytical chemistry laboratory and its integration with an undergraduate environmental law course. The course is designed to introduce students to the principles of performance-based analytical methods and the use of environmental indicators to perform environmental assessments. Conducting a series of chemical and toxicological tests, chemistry students perform an environmental assessment on the watershed of the mythical City of Rowan. Law students use these assessments to develop legal arguments under both the Safe Drinking Water Act and the Clean Water Act.
An analytical approach to estimate the number of small scatterers in 2D inverse scattering problems
NASA Astrophysics Data System (ADS)
Fazli, Roohallah; Nakhkash, Mansor
2012-07-01
This paper presents an analytical method to estimate the location and number of actual small targets in 2D inverse scattering problems. This method is motivated from the exact maximum likelihood estimation of signal parameters in white Gaussian noise for the linear data model. In the first stage, the method uses the MUSIC algorithm to acquire all possible target locations and in the next stage, it employs an analytical formula that works as a spatial filter to determine which target locations are associated to the actual ones. The ability of the method is examined for both the Born and multiple scattering cases and for the cases of well-resolved and non-resolved targets. Many numerical simulations using both the coincident and non-coincident arrays demonstrate that the proposed method can detect the number of actual targets even in the case of very noisy data and when the targets are closely located. Using the experimental microwave data sets, we further show that this method is successful in specifying the number of small inclusions.
Sockalingam, Nachamma; Rotgans, Jerome I; Schmidt, Henk G
2011-10-01
This study investigated the influence of five problem characteristics on students' achievement-related classroom behaviors and academic achievement. Data from 5,949 polytechnic students in PBL curricula across 170 courses were analyzed by means of path analysis. The five problem characteristics were: (1) problem clarity, (2) problem familiarity, (3) the extent to which the problem stimulated group discussion, (4) self-study, and (5) identification of learning goals. The results showed that problem clarity led to more group discussion, identification of learning goals, and self-study than problem familiarity. On the other hand, problem familiarity had a stronger and direct impact on academic achievement.
Analytic P-value calculation for the higher criticism test in finite d problems.
Barnett, Ian J; Lin, Xihong
The higher criticism is effective for testing a joint null hypothesis against a sparse alternative, e.g., for testing the effect of a gene or a genetic pathway that consists of d genetic markers. Accurate p-value calculations for the higher criticism based on the asymptotic distribution require a very large d, which is not the case for the number of genetic variants in a gene or a pathway. In this paper we propose an analytic method that accurately computes the p-value of the higher criticism test for finite d problems. Unlike previous treatments, this method does not rely on asymptotics in d or simulation, and is exact for arbitrary d when the test statistics are normally distributed. The method is particularly computationally advantageous when d is not large. We illustrate the proposed method with a case-control genome-wide association study of lung cancer and compare its power to competing methods through simulations.
Friedman, Ronald S; Förster, Jens
2005-02-01
In 4 experiments, participants were led to focus on either the prospect of positive outcomes (approach anticipation) or the prospect of negative outcomes (avoidance anticipation) and were subsequently administered behavioral measures of relative hemispheric activation. It was found that approach, relative to avoidance-related anticipatory states, produced greater relative right (diminished relative left) hemispheric activation. Experiment 3 additionally demonstrated that this pattern of activation was reversed when approach and avoidance states were not merely anticipatory but were also emotionally arousing. Finally, Experiment 4 replicated earlier findings demonstrating an influence of approach and avoidance anticipatory states on creativity and analytical problem solving (R. S. Friedman & J. Forster, 2001, 2003) and provided evidence that such effects are mediated by differences in relative hemispheric activation.
Analytical solutions for some defect problems in 1D hexagonal and 2D octagonal quasicrystals
NASA Astrophysics Data System (ADS)
Wang, X.; Pan, E.
2008-05-01
We study some typical defect problems in one-dimensional (1D) hexagonal and two-dimensional (2D) octagonal quasicrystals. The first part of this investigation addresses in detail a uniformly moving screw dislocation in a 1D hexagonal piezoelectric quasicrystal with point group 6mm. A general solution is derived in terms of two functions \\varphi_1, \\varphi_2, which satisfy wave equations, and another harmonic function \\varphi_3. Elementary expressions for the phonon and phason displacements, strains, stresses, electric potential, electric fields and electric displacements induced by the moving screw dislocation are then arrived at by employing the obtained general solution. The derived solution is verified by comparison with existing solutions. Also obtained in this part of the investigation is the total energy of the moving screw dislocation. The second part of this investigation is devoted to the study of the interaction of a straight dislocation with a semi-infinite crack in an octagonal quasicrystal. Here the crack penetrates through the solid along the period direction and the dislocation line is parallel to the period direction. We first derive a general solution in terms of four analytic functions for plane strain problem in octagonal quasicrystals by means of differential operator theory and the complex variable method. All the phonon and phason displacements and stresses can be expressed in terms of the four analytic functions. Then we derive the exact solution for a straight dislocation near a semi-infinite crack in an octagonal quasicrystal, and also present the phonon and phason stress intensity factors induced by the straight dislocation and remote loads.
NASA Technical Reports Server (NTRS)
Fasanella, E. L.; Mcgehee, J. R.; Pappas, M. S.
1977-01-01
An experimental and analytical investigation was conducted to determine which characteristics of a light aircraft landing gear influence gear dynamic behavior significantly. The investigation focused particularly on possible modification for load control. Pseudostatic tests were conducted to determine the gear fore-and-aft spring constant, axial friction as a function of drag load, brake pressure-torque characteristics, and tire force-deflection characteristics. To study dynamic tire response, vertical drops were conducted at impact velocities of 1.2, 1.5, and 1.8 m/s onto a level surface; to determine axial-friction effects, a second series of vertical drops were made at 1.5 m/s onto surfaces inclined 5 deg and 10 deg to the horizontal. An average dynamic axial-friction coefficient of 0.15 was obtained by comparing analytical data with inclined surface drop test data. Dynamic strut bending and associated axial friction were found to be severe for the drop tests on the 10 deg surface.
NASA Astrophysics Data System (ADS)
Bayón, L.; Grau, J. M.; Ruiz, M. M.; Suárez, P. M.
2012-12-01
One of the most well-known problems in the field of Microeconomics is the Firm's Cost-Minimization Problem. In this paper we establish the analytical expression for the cost function using the Cobb-Douglas model and considering maximum constraints for the inputs. Moreover we prove that it belongs to the class C1.
NASA Technical Reports Server (NTRS)
Romanofsky, Robert R.
1989-01-01
In this report, a thorough analytical procedure is developed for evaluating the frequency-dependent loss characteristics and effective permittivity of microstrip lines. The technique is based on the measured reflection coefficient of microstrip resonator pairs. Experimental data, including quality factor Q, effective relative permittivity, and fringing for 50-omega lines on gallium arsenide (GaAs) from 26.5 to 40.0 GHz are presented. The effects of an imperfect open circuit, coupling losses, and loading of the resonant frequency are considered. A cosine-tapered ridge-guide text fixture is described. It was found to be well suited to the device characterization.
NASA Technical Reports Server (NTRS)
Lake, Renee C.; Izadpanah, Amir P.; Baucom, Robert M.
1993-01-01
The results from a study aimed at improving the dynamic and aerodynamic characteristics of composite rotor blades through the use of extension-twist coupling are presented. A set of extension-twist-coupled composite spars was manufactured with four plies of graphite-epoxy cloth prepreg. These spars were noncircular in cross-section design and were therefore subject to warping deformations. Three different cross-sectional geometries were developed: D-shape, square, and flattened ellipse. Three spars of each type were fabricated to assess the degree of repeatability in the manufacturing process of extension-twist-coupled structures. Results from free-free vibration tests of the spars were compared with results from normal modes and frequency analyses of companion shell-finite-element models. Five global modes were identified within the frequency range from 0 to 2000 Hz for each spar. The experimental results for only one D-shape spar could be determined, however, and agreed within 13.8 percent of the analytical results. Frequencies corresponding to the five global modes for the three square spars agreed within 9.5, 11.6, and 8.5 percent of the respective analytical results and for the three elliptical spars agreed within 4.9, 7.7, and 9.6 percent of the respective analytical results.
Characteristics, Properties and Analytical Methods of Amoxicillin: A Review with Green Approach.
de Marco, Bianca Aparecida; Natori, Jéssica Sayuri Hisano; Fanelli, Stefany; Tótoli, Eliane Gandolpho; Salgado, Hérida Regina Nunes
2017-01-12
Bacterial infections are the second leading cause of global mortality. Considering this fact, it is extremely important studying the antimicrobial agents. Amoxicillin is an antimicrobial agent that belongs to the class of penicillins; it has bactericidal activity and is widely used in the Brazilian health system. In literature, some analytical methods are found for the identification and quantification of this penicillin, which are essential for its quality control, which ensures maintaining the product characteristics, therapeutic efficacy and patient's safety. Thus, this study presents a brief literature review on amoxicillin and the analytical methods developed for the analysis of this drug in official and scientific papers. The major analytical methods found were high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography (U-HPLC), capillary electrophoresis and iodometry and diffuse reflectance infrared Fourier transform. It is essential to note that most of the developed methods used toxic and hazardous solvents, which makes necessary industries and researchers choose to develop environmental-friendly techniques to provide enhanced benefits to environment and staff.
NASA Technical Reports Server (NTRS)
Landrum, E. J.; Miller, D. S.
1980-01-01
Trends toward the automation of the design process for airplanes and missiles accentuate the need for analytic techniques for the prediction of aerodynamic characteristics. A number of computer codes have been developed or are under development which show promise of significantly improving the estimation of aerodynamic characteristics for arbitrarily-shaped bodies at supersonic speeds. The programs considered range in complexity from a simple linearized solution employing slender body theory to an exact finite difference solution of the Euler equations. The results from five computer codes are compared with experimental data to determine the accuracy, range of applicability, ease of use, and computer time and cost of the programs. The results provide a useful guide for selecting the appropriate method for treating bodies at the various levels of an automated design process.
NASA Astrophysics Data System (ADS)
Miranda, E.; Palumbo, F.
2011-07-01
It is shown in this communication that the Fowler-Nordheim (FN) tunneling expression for the current-voltage ( I- V) characteristic can be analytically inverted so that an exact expression for the voltage-current ( V- I) characteristic can be obtained. The solution of the resulting implicit equation is found using the Lambert W function, i.e. the solution of the transcendental equation we w = x. The reported expressions are supported by experimental I- V curves measured in thin (≈5 nm) SiO 2 films in MOS capacitors. The analysis includes the case of a tunneling oxide with a large series resistance. For practical purposes, a closed-form expression for W based on a Padé-type approximation is also provided.
NASA Technical Reports Server (NTRS)
Lara, Martin; Palacian, Jesus F.
2007-01-01
Frozen orbits of the Hill problem are determined in the double averaged problem, where short and long period terms are removed by means of Lie transforms. The computation of initial conditions of corresponding quasi periodic solutions in the non-averaged problem is straightforward for the perturbation method used provides the explicit equations of the transformation that connects the averaged and non-averaged models. A fourth order analytical theory reveals necessary for the accurate computation of quasi periodic, frozen orbits.
Demands, control, and support: a meta-analytic review of work characteristics interrelationships.
Luchman, Joseph N; González-Morales, M Gloria
2013-01-01
The job demands-control-support model (DCS; Karasek, 1979) is an influential theory for understanding how work characteristics relate to employee well-being, health, and performance. However, previous research has largely neglected theory-building regarding the interrelationships between job demands, control, and support. We remedy such theoretical underdevelopment by reviewing and integrating theory on the relationships between demands, control, and support to develop five hypotheses. We test our hypotheses within a meta-analytic framework using a set of 106 studies. Our results show negative demands-supervisor support and demands-coworker support relationships, but no significant demand-control relationship. Our findings also indicate positive control-supervisor support and control-coworker support relationships. Using the meta-analytic effect sizes, we also estimate two competing structural equation models intended to discern which theoretical model using DCS work characteristics to predict occupational strain and well-being is more consistent with our data. Our results suggest that job control and both sources of social support should be treated independently, as opposed to indicators of a shared latent factor, in terms of their prediction of well-being and job demands. Our study offers support for the usefulness of the DCS and more modern conceptualizations of the working environment in understanding the employee work experience and for predicting important work outcomes. (
Hard Data Analytics Problems Make for Better Data Analysis Algorithms: Bioinformatics as an Example.
Bacardit, Jaume; Widera, Paweł; Lazzarini, Nicola; Krasnogor, Natalio
2014-09-01
Data mining and knowledge discovery techniques have greatly progressed in the last decade. They are now able to handle larger and larger datasets, process heterogeneous information, integrate complex metadata, and extract and visualize new knowledge. Often these advances were driven by new challenges arising from real-world domains, with biology and biotechnology a prime source of diverse and hard (e.g., high volume, high throughput, high variety, and high noise) data analytics problems. The aim of this article is to show the broad spectrum of data mining tasks and challenges present in biological data, and how these challenges have driven us over the years to design new data mining and knowledge discovery procedures for biodata. This is illustrated with the help of two kinds of case studies. The first kind is focused on the field of protein structure prediction, where we have contributed in several areas: by designing, through regression, functions that can distinguish between good and bad models of a protein's predicted structure; by creating new measures to characterize aspects of a protein's structure associated with individual positions in a protein's sequence, measures containing information that might be useful for protein structure prediction; and by creating accurate estimators of these structural aspects. The second kind of case study is focused on omics data analytics, a class of biological data characterized for having extremely high dimensionalities. Our methods were able not only to generate very accurate classification models, but also to discover new biological knowledge that was later ratified by experimentalists. Finally, we describe several strategies to tightly integrate knowledge extraction and data mining in order to create a new class of biodata mining algorithms that can natively embrace the complexity of biological data, efficiently generate accurate information in the form of classification/regression models, and extract valuable new
NASA Astrophysics Data System (ADS)
Siddheshwar, P. G.; Mahabaleswar, U. S.; Andersson, H. I.
2013-08-01
The paper discusses a new analytical procedure for solving the non-linear boundary layer equation arising in a linear stretching sheet problem involving a Newtonian/non-Newtonian liquid. On using a technique akin to perturbation the problem gives rise to a system of non-linear governing differential equations that are solved exactly. An analytical expression is obtained for the stream function and velocity as a function of the stretching parameters. The Clairaut equation is obtained on consideration of consistency and its solution is shown to be that of the stretching sheet boundary layer equation. The present study throws light on the analytical solution of a class of boundary layer equations arising in the stretching sheet problem
A three-dimensional (3D) analytical model for subthreshold characteristics of uniformly doped FinFET
NASA Astrophysics Data System (ADS)
Tripathi, Shweta; Narendar, Vadthiya
2015-07-01
In this paper, three dimensional (3D) analytical model for subthreshold characteristics of doped FinFET has been presented. The separation of variables technique is used to solve the 3D Poisson's equation analytically with appropriate boundary conditions so as to obtain the expression for channel potential. The thus obtained potential distribution function has been employed in deriving subthreshold current and subthreshold slope model. The channel potential characteristics have been studied as a function of various device parameters such as gate length, gate oxide thickness and channel doping. The proposed analytical model results have been validated by comparing with the simulation data obtained by the 3D device simulator ATLAS™ from Silvaco.
NASA Astrophysics Data System (ADS)
Hamed, Haikel Ben; Bennacer, Rachid
2008-08-01
This work consists in evaluating algebraically and numerically the influence of a disturbance on the spectral values of a diagonalizable matrix. Thus, two approaches will be possible; to use the theorem of disturbances of a matrix depending on a parameter, due to Lidskii and primarily based on the structure of Jordan of the no disturbed matrix. The second approach consists in factorizing the matrix system, and then carrying out a numerical calculation of the roots of the disturbances matrix characteristic polynomial. This problem can be a standard model in the equations of the continuous media mechanics. During this work, we chose to use the second approach and in order to illustrate the application, we choose the Rayleigh-Bénard problem in Darcy media, disturbed by a filtering through flow. The matrix form of the problem is calculated starting from a linear stability analysis by a finite elements method. We show that it is possible to break up the general phenomenon into other elementary ones described respectively by a disturbed matrix and a disturbance. A good agreement between the two methods was seen. To cite this article: H.B. Hamed, R. Bennacer, C. R. Mecanique 336 (2008).
An analytic solution of the stochastic storage problem applicable to soil water
Milly, P.C.D.
1993-01-01
The accumulation of soil water during rainfall events and the subsequent depletion of soil water by evaporation between storms can be described, to first order, by simple accounting models. When the alternating supplies (precipitation) and demands (potential evaporation) are viewed as random variables, it follows that soil-water storage, evaporation, and runoff are also random variables. If the forcing (supply and demand) processes are stationary for a sufficiently long period of time, an asymptotic regime should eventually be reached where the probability distribution functions of storage, evaporation, and runoff are stationary and uniquely determined by the distribution functions of the forcing. Under the assumptions that the potential evaporation rate is constant, storm arrivals are Poisson-distributed, rainfall is instantaneous, and storm depth follows an exponential distribution, it is possible to derive the asymptotic distributions of storage, evaporation, and runoff analytically for a simple balance model. A particular result is that the fraction of rainfall converted to runoff is given by (1 - R−1)/(eα(1−R−1) − R−1), in which R is the ratio of mean potential evaporation to mean rainfall and a is the ratio of soil water-holding capacity to mean storm depth. The problem considered here is analogous to the well-known problem of storage in a reservoir behind a dam, for which the present work offers a new solution for reservoirs of finite capacity. A simple application of the results of this analysis suggests that random, intraseasonal fluctuations of precipitation cannot by themselves explain the observed dependence of the annual water balance on annual totals of precipitation and potential evaporation.
The problem of effect size heterogeneity in meta-analytic structural equation modeling.
Yu, Jia Joya; Downes, Patrick E; Carter, Kameron M; O'Boyle, Ernest H
2016-10-01
Scholars increasingly recognize the potential of meta-analytic structural equation modeling (MASEM) as a way to build and test theory (Bergh et al., 2016). Yet, 1 of the greatest challenges facing MASEM researchers is how to incorporate and model meaningful effect size heterogeneity identified in the bivariate meta-analysis into MASEM. Unfortunately, common MASEM approaches in applied psychology (i.e., Viswesvaran & Ones, 1995) fail to account for effect size heterogeneity. This means that MASEM effect sizes, path estimates, and overall fit values may only generalize to a small segment of the population. In this research, we quantify this problem and introduce a set of techniques that retain both the true score relationships and the variability surrounding those relationships in estimating model parameters and fit indices. We report our findings from simulated data as well as from a reanalysis of published MASEM studies. Results demonstrate that both path estimates and overall model fit indices are less representative of the population than existing MASEM research would suggest. We suggest 2 extension MASEM techniques that can be conducted using online software or in R, to quantify the stability of model estimates across the population and allow researchers to better build and test theory. (PsycINFO Database Record
Chen, Frances R; Raine, Adrian; Granger, Douglas A
2015-01-01
Individual differences in the psychobiology of the stress response have been linked to behavior problems in youth yet most research has focused on single signaling molecules released by either the hypothalamic-pituitary-adrenal axis or the autonomic nervous system. As our understanding about biobehavioral relationships develops it is clear that multiple signals from the biological stress systems work in coordination to affect behavior problems. Questions are raised as to whether coordinated effects should be statistically represented as ratio or interactive terms. We address this knowledge gap by providing a theoretical overview of the concepts and rationales, and illustrating the analytical tactics. Salivary samples collected from 446 youth aged 11-12 were assayed for salivary alpha-amylase (sAA), dehydroepiandrosterone-sulfate (DHEA-s) and cortisol. Coordinated effect of DHEA-s and cortisol, and coordinated effect of sAA and cortisol on externalizing and internalizing problems (Child Behavior Checklist) were tested with the ratio and the interaction approaches using multi-group path analysis. Findings consistent with previous studies include a positive association between cortisol/DHEA-s ratio and internalizing problems; and a negative association between cortisol and externalizing problems conditional on low levels of sAA. This study highlights the importance of matching analytical strategy with research hypothesis when integrating salivary bioscience into research in behavior problems. Recommendations are made for investigating multiple salivary analytes in relation to behavior problems. Copyright © 2014 Elsevier Ltd. All rights reserved.
Applied Analytical Methods for Solving Some Problems of Wave Propagation in the Coastal Areas
NASA Astrophysics Data System (ADS)
Gagoshidze, Shalva; Kodua, Manoni
2016-04-01
Analytical methods, easy for application, are proposed for the solution of the following four classical problems of coastline hydro mechanics: 1. Refraction of waves on coast slopes of arbitrary steepness; 2. Wave propagation in tapering water areas; 3. Longitudinal waves in open channels; 4. Long waves on uniform and non-uniform flows of water. The first three of these problems are solved by the direct Galerkin-Kantorovich method with a choice , of basic functions which completely satisfy all boundary conditions. This approach leads to obtaining new evolutionary equations which can be asymptotically solved by the WKB method. The WKB solution of the first problem enables us to easily determine the three-dimensional field of velocities and to construct the refraction picture of the wave surface near the coast having an arbitrary angle of slope to the horizon varying from 0° to 180°. This solution, in particular for a vertical cliff, fully agrees with Stoker's particular but difficult solution. Moreover, it is shown for the first time that our Schrödinger type evolutionary equation leads to the formation of the so-called "potential wells" if the angle of coast slope to the horizon exceeds 45°, while the angle given at infinity (i.e. at a large distance from the shore) between the wave crests and the coastline exceeds 75°. This theoretical result expressed in terms of elementary functions is well consistent with the experimental observations and with lot of aerial photographs of waves in the coastal zones of the oceans [1,2]. For the second problem we introduce the notions of "wide" and "narrow" water areas. It is shown that Green's law on the wave height growth holds only for the narrow part of the water area, whereas in the wide part the tapering of the water area leads to an insignificant decrease of the wave height. For the third problem, the bank slopes of trapezoidal channels are assumed to have an arbitrary angle of steepness. So far we have known the
Yang, D G; Choi, Y H; Kim, Y G; Song, J B; Lee, H G
2016-03-01
This paper presents results, experimental and analytical, of the electrical characteristics of GdBCO single-pancake coils co-wound with a brass tape as metallic insulation (MI coil). The GdBCO pancakes were subjected to sudden discharge, charge-discharge, and over-current tests. The sudden discharge and charge-discharge test results of the MI coil demonstrated that MI coils can be charged and discharged significantly faster than non-insulated coils that are wound only with GdBCO tape. In over-current tests at 150 A (1.25I(c)), the MI coil exhibited better electrical behavior, i.e., self-protecting features, than its counterpart co-wound with Kapton tape, an insulator. Moreover, the experimental and analytical results are in agreement, validating the use of a concise equivalent parallel-RL circuit model for the MI coil to characterize its electrical behavior. Overall, the MI winding technique is highly promising to help build compact, mechanically robust, and self-protecting magnets composed of REBCO pancake coils. With no organic material in the winding, MI REBCO pancakes will be immune to neutron radiation damage, making the MI winding technique a viable option for fusion reactors, such as for toroidal field, poroidal field magnets, and central solenoid.
NASA Astrophysics Data System (ADS)
Yang, D. G.; Choi, Y. H.; Kim, Y. G.; Song, J. B.; Lee, H. G.
2016-03-01
This paper presents results, experimental and analytical, of the electrical characteristics of GdBCO single-pancake coils co-wound with a brass tape as metallic insulation (MI coil). The GdBCO pancakes were subjected to sudden discharge, charge-discharge, and over-current tests. The sudden discharge and charge-discharge test results of the MI coil demonstrated that MI coils can be charged and discharged significantly faster than non-insulated coils that are wound only with GdBCO tape. In over-current tests at 150 A (1.25Ic), the MI coil exhibited better electrical behavior, i.e., self-protecting features, than its counterpart co-wound with Kapton tape, an insulator. Moreover, the experimental and analytical results are in agreement, validating the use of a concise equivalent parallel-RL circuit model for the MI coil to characterize its electrical behavior. Overall, the MI winding technique is highly promising to help build compact, mechanically robust, and self-protecting magnets composed of REBCO pancake coils. With no organic material in the winding, MI REBCO pancakes will be immune to neutron radiation damage, making the MI winding technique a viable option for fusion reactors, such as for toroidal field, poroidal field magnets, and central solenoid.
ERIC Educational Resources Information Center
Thorsland, Martin N.; Novak, Joseph D.
1974-01-01
Described is an approach to assessment of intuitive and analytic modes of thinking in physics. These modes of thinking are associated with Ausubel's theory of learning. High ability in either intuitive or analytic thinking was associated with success in college physics, with high learning efficiency following a pattern expected on the basis of…
ERIC Educational Resources Information Center
Thorsland, Martin N.; Novak, Joseph D.
1974-01-01
Described is an approach to assessment of intuitive and analytic modes of thinking in physics. These modes of thinking are associated with Ausubel's theory of learning. High ability in either intuitive or analytic thinking was associated with success in college physics, with high learning efficiency following a pattern expected on the basis of…
Characteristics of Moral Problems as Formulated by Gifted Adolescents.
ERIC Educational Resources Information Center
Colangelo, Nicholas
1982-01-01
Gifted adolescents from grades 9-12 were asked to generate stories involving a moral problem and to provide a solution. Half of the moral problems written involved friendship or a love relationship; 92 percent of the students were able to give guidelines for solutions to their moral problems. (RM)
Critical Task Characteristics in Problem-Based Learning
ERIC Educational Resources Information Center
Otting, Hans; Zwaal, Wichard
2006-01-01
Tasks and problems in problem-based learning (PBL) are supposed to trigger and structure the learning process. The quality of problems in PBL is generally regarded as an important driver of the individual and collaborative learning processes. Although the importance of the PBL task is widely recognized, there is a lack of empirical findings and…
Krupskaia, E V; Machinskaia, R I
2006-01-01
The information concerning specific features of different attention components (alertness, sustention and selectivity) in children with attention deficit hyperactivity disorder (ADHD) is analyzed and systematized. According to the data reviewed, behavioral and attention problems described as ADHD are not homogeneous. Literature analysis of attention characteristics in children with ADHD shows that different components can be disrupted if ADHD is diagnosed as inattentive or combined subtype, but the main deficit in this case is that of selective voluntary attention. In case of hyperactivity/impulsivity subtype of ADHD, attention is impaired mainly in its brain activation components.
A measurement-based analytical approach to the bioluminescence tomography problem
NASA Astrophysics Data System (ADS)
Erkol, Hakan; Demirkiran, Aytac; Kipergil, Esra-Aytac; Uluc, Nasire; Unlu, Mehmet B.
2014-03-01
This work presents an analytical approach for the solution of the tissue diffusion equation based on the bound- ary measurements. We consider a bioluminescent point source in both homogeneous and heterogeneous circular turbid media. The point source is described by the Dirac delta function. Analytical expressions for the strength and position of the point source are obtained introducing boundary measurements and then applying appropriate boundary conditions. In addition, numerical simulations are performed for the position of the source. Calculations show that that the analytical results are in a good accordance with the numerical results.
NASA Astrophysics Data System (ADS)
Moench, Allen F.
2008-06-01
A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric soil moisture measured at various times and distances from the pumped well. Analytical analyses were conducted with the model published in 2001 by Moench and colleagues, which allows for gradual drainage but does not include unsaturated zone characteristics, and the model published in 2006 by Mathias and Butler, which assumes that moisture retention and relative hydraulic conductivity (RHC) in the unsaturated zone are exponential functions of pressure head. Parameters estimated with either model yield good matches between measured and simulated drawdowns in piezometers. Numerical analyses were conducted with two versions of VS2DT: one that uses traditional Brooks and Corey functional relations and one that uses a RHC function introduced in 2001 by Assouline that includes an additional parameter that accounts for soil structure and texture. The analytical model of Mathias and Butler and numerical model of VS2DT with the Assouline model both show that the RHC function must contain a fitting parameter that is different from that used in the moisture retention function. Results show the influence of field-scale heterogeneity and suggest that the RHC at the Borden site declines more rapidly with elevation above the top of the capillary fringe than would be expected if the parameters were to reflect local- or core-scale soil structure and texture.
Moench, A.F.
2008-01-01
A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric soil moisture measured at various times and distances from the pumped well. Analytical analyses were conducted with the model published in 2001 by Moench and colleagues, which allows for gradual drainage but does not include unsaturated zone characteristics, and the model published in 2006 by Mathias and Butler, which assumes that moisture retention and relative hydraulic conductivity (RHC) in the unsaturated zone are exponential functions of pressure head. Parameters estimated with either model yield good matches between measured and simulated drawdowns in piezometers. Numerical analyses were conducted with two versions of VS2DT: one that uses traditional Brooks and Corey functional relations and one that uses a RHC function introduced in 2001 by Assouline that includes an additional parameter that accounts for soil structure and texture. The analytical model of Mathias and Butler and numerical model of VS2DT with the Assouline model both show that the RHC function must contain a fitting parameter that is different from that used in the moisture retention function. Results show the influence of field-scale heterogeneity and suggest that the RHC at the Borden site declines more rapidly with elevation above the top of the capillary fringe than would be expected if the parameters were to reflect local- or core-scale soil structure and texture.
Gonis, Antonios; Daene, Markus W; Nicholson, Don M; Stocks, George Malcolm
2012-01-01
We have developed and tested in terms of atomic calculations an exact, analytic and computationally simple procedure for determining the functional derivative of the exchange energy with respect to the density in the implementation of the Kohn Sham formulation of density functional theory (KS-DFT), providing an analytic, closed-form solution of the self-interaction problem in KS-DFT. We demonstrate the efficacy of our method through ground-state calculations of the exchange potential and energy for atomic He and Be atoms, and comparisons with experiment and the results obtained within the optimized effective potential (OEP) method.
Analytic Solution to the Problem of Aircraft Electric Field Mill Calibration
NASA Technical Reports Server (NTRS)
Koshak, William
2003-01-01
It is by no means a simple task to retrieve storm electric fields from an aircraft instrumented with electric field mill sensors. The presence of the aircraft distorts the ambient field in a complicated way. Before retrievals of the storm field can be made, the field mill measurement system must be "calibrated". In other words, a relationship between impressed (i.e., ambient) electric field and mill output must be established. If this relationship can be determined, it is mathematically inverted so that ambient field can be inferred from the mill outputs. Previous studies have primarily focused on linear theories where the relationship between ambient field and mill output is described by a "calibration matrix" M. Each element of the matrix describes how a particular component of the ambient field is enhanced by the aircraft. For example the product M(sub ix), E(sub x), is the contribution of the E(sub x) field to the i(th) mill output. Similarly, net aircraft charge (described by a "charge field component" E(sub q)) contributes an amount M(sub iq)E(sub q) to the output of the i(th) sensor. The central difficulty in obtaining M stems from the fact that the impressed field (E(sub x), E(sub y), E(sub z), E(sub q) is not known but is instead estimated. Typically, the aircraft is flown through a series of roll and pitch maneuvers in fair weather, and the values of the fair weather field and aircraft charge are estimated at each point along the aircraft trajectory. These initial estimates are often highly inadequate, but several investigators have improved the estimates by implementing various (ad hoc) iterative methods. Unfortunately, none of the iterative methods guarantee absolute convergence to correct values (i.e., absolute convergence to correct values has not been rigorously proven). In this work, the mathematical problem is solved directly by analytic means. For m mills installed on an arbitrary aircraft, it is shown that it is possible to solve for a single 2m
Analytic Solution to the Problem of Aircraft Electric Field Mill Calibration
NASA Technical Reports Server (NTRS)
Koshak, William
2003-01-01
It is by no means a simple task to retrieve storm electric fields from an aircraft instrumented with electric field mill sensors. The presence of the aircraft distorts the ambient field in a complicated way. Before retrievals of the storm field can be made, the field mill measurement system must be "calibrated". In other words, a relationship between impressed (i.e., ambient) electric field and mill output must be established. If this relationship can be determined, it is mathematically inverted so that ambient field can be inferred from the mill outputs. Previous studies have primarily focused on linear theories where the relationship between ambient field and mill output is described by a "calibration matrix" M. Each element of the matrix describes how a particular component of the ambient field is enhanced by the aircraft. For example the product M(sub ix), E(sub x), is the contribution of the E(sub x) field to the i(th) mill output. Similarly, net aircraft charge (described by a "charge field component" E(sub q)) contributes an amount M(sub iq)E(sub q) to the output of the i(th) sensor. The central difficulty in obtaining M stems from the fact that the impressed field (E(sub x), E(sub y), E(sub z), E(sub q) is not known but is instead estimated. Typically, the aircraft is flown through a series of roll and pitch maneuvers in fair weather, and the values of the fair weather field and aircraft charge are estimated at each point along the aircraft trajectory. These initial estimates are often highly inadequate, but several investigators have improved the estimates by implementing various (ad hoc) iterative methods. Unfortunately, none of the iterative methods guarantee absolute convergence to correct values (i.e., absolute convergence to correct values has not been rigorously proven). In this work, the mathematical problem is solved directly by analytic means. For m mills installed on an arbitrary aircraft, it is shown that it is possible to solve for a single 2m
Arnab, Salman M.; Kabir, M. Z.
2014-01-21
An analytical model for analyzing the current-voltage (J-V) characteristics of bulk heterojunction (BHJ) organic solar cells is developed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun's model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The charge carrier concentrations and hence the photocurrent are calculated by solving the carrier continuity equation for both holes and electrons in the organic layer. The overall load current is calculated considering the actual solar spectrum and voltage dependent forward dark current. The model is verified by published experimental results. The efficiency of the P3HT:PCBM based solar cells critically depends on the dissociation of bound EHPs. On the other hand, cells made of a blend of the conjugated polymer (PCDTBT) with the soluble fullerene derivative (PCBM) show nearly unity dissociation efficiency, and their cell efficiency strongly depends on the charge collection efficiency. The effects of carrier lifetimes on the performance of PCDTBT solar cells have also been studied. The model is also used to investigate the effect of titanium oxide (TiO{sub x}) layer (at the back contact) on the J-V characteristics of PCDTBT solar cells. The results of this paper indicate that improvement of charge carrier transport in PCDTBT:PCBM blend and dissociation of bound EHPs in P3HT:PCBM blend are extremely important to increase the power conversion efficiency of the respective BHJ solar cells.
Hoppmann, Christiane A; Blanchard-Fields, Fredda
2011-09-01
Problem-solving does not take place in isolation and often involves social others such as spouses. Using repeated daily life assessments from 98 older spouses (M age = 72 years; M marriage length = 42 years), the present study examined theoretical notions from social-contextual models of coping regarding (a) the origins of problem-solving variability and (b) associations between problem-solving and specific problem-, person-, and couple- characteristics. Multilevel models indicate that the lion's share of variability in everyday problem-solving is located at the level of the problem situation. Importantly, participants reported more proactive emotion regulation and collaborative problem-solving for social than nonsocial problems. We also found person-specific consistencies in problem-solving. That is, older spouses high in Neuroticism reported more problems across the study period as well as less instrumental problem-solving and more passive emotion regulation than older spouses low in Neuroticism. Contrary to expectations, relationship satisfaction was unrelated to problem-solving in the present sample. Results are in line with the stress and coping literature in demonstrating that everyday problem-solving is a dynamic process that has to be viewed in the broader context in which it occurs. Our findings also complement previous laboratory-based work on everyday problem-solving by underscoring the benefits of examining everyday problem-solving as it unfolds in spouses' own environment.
Kocifaj, Miroslav
2011-06-10
The approximate bulk-scattering phase function of a polydisperse system of dust particles is derived in an analytical form. In the theoretical solution, the particle size distribution is modeled by a modified gamma function that can satisfy various media differing in modal radii. Unlike the frequently applied power law, the modified gamma distribution shows no singularity when the particle radius approaches zero. The approximate scattering phase function is related to the parameters of the size distribution function. This is an important advantage compared to the empirical Henyey-Greenstein (HG) approximation, which is a simple function of the average cosine. However, any optimized value of average cosine of the HG function cannot provide the information on particle microphysical characteristics, such as the size distribution function. In this paper, the mapping between average cosine and the parameters of size distribution function is given by a semianalytical expression that is applicable in rapid numerical simulations on various dust populations. In particular, the modal radius and half-width can be quickly estimated using the presented formulas.
Problem-Based Learning: Instructor Characteristics, Competencies, and Professional Development
2011-01-01
Department of the Army Deputy Chief of Staff, G1 Authorized and approved for distribution: BARBARA A. BLACK, Ph.D. MICHELLE SAMS...problems used to situate learning serve a valid, applicable instructional purpose ( Barron , Schwartz, Vye, et al., 1998; Thompson, 1990). For instance...accountability ( Barron et al., 1998). The collaboration requirements of a problem should be representative of the transfer environment such that learner
Al-Swiahb, Jamil Nasser; Hwang, Eul Seung; Kong, Ji Sun; Kim, Woo Jin; Yeo, Sang Won; Park, Shi Nae
2016-12-01
This study was performed to analyze clinical and audiologic characteristics of sensorineural tinnitus and to investigate the associating factors reflecting psychological aspects of stress and depression of the patients. This is a retrospective analytical study conducted in a tinnitus clinic of a tertiary referral center of a university hospital. The medical records of 216 patients suffering from sensorineural tinnitus were thoroughly evaluated to determine correlations between clinical and audiological characteristics, including age, sex, predisposing or etiologic factors, hearing levels up to extended high frequencies, and tinnitus severity. Psychological aspects of stress and depression were also evaluated and analyzed to seek the associations with tinnitus severity. All data were stored in our database bank and were statistically analyzed. Our study subjects showed a slight male predominance. The highest percentage of tinnitus was found in patients of 60-80 years old. Only 32.5 % of tinnitus patients were subjectively aware of their hearing loss, whereas 73 % of subjects had hearing deficits in some frequencies in their audiogram. Hearing impairments were of the low-frequency sensorineural type in 18.2 % of patients and were limited to the high frequencies in 77.9 % of patients. Tinnitus was unilateral in 51 % of patients and had a tonal nature in 45 % of patients. In total, 45.8 % of patients with high-frequency sensorineural hearing loss had high-pitched tinnitus. There were significant correlations between tinnitus severity, loudness and annoyance. Correlations with THI (Tinnitus Handicap Inventory) and Beck depression index scores were also found. Sensorineural tinnitus was related with hearing loss in some frequencies nevertheless of patients' own awareness of hearing loss. Loudness and annoyance of tinnitus seems to be two important factors reflecting psychological problems of patients' stress and depression.
Filho, J. F. P.
2013-07-01
In this work, an analytical discrete ordinates method is used to solve a nodal formulation of a neutron transport problem in x, y-geometry. The proposed approach leads to an important reduction in the order of the associated eigenvalue systems, when combined with the classical level symmetric quadrature scheme. Auxiliary equations are proposed, as usually required for nodal methods, to express the unknown fluxes at the boundary introduced as additional unknowns in the integrated equations. Numerical results, for the problem defined by a two-dimensional region with a spatially constant and isotropically emitting source, are presented and compared with those available in the literature. (authors)
Procida, Giuseppe; Cichelli, Angelo; Lagazio, Corrado; Conte, Lanfranco S
2016-01-15
The volatile fraction of virgin olive oil is characterised by low molecular weight compounds that vaporise at room temperature. In order to obtain an aroma profile similar to natural olfactory perception, the composition of the volatile compounds was determined by applying dynamic headspace gas chromatography, performed at room temperature, with a cryogenic trap directly connected to a gas chromatograph-mass spectrometer system. Samples were also evaluated according to European Union and International Olive Council official methods for sensory evaluation. In this paper, the composition of the volatile fraction of 25 extra virgin olive oils from different regions of Italy was analysed and some preliminary considerations on relationships between chemical composition of volatile fraction and sensory characteristics are reported. Forty-two compounds were identified by means of the particular analytical technique used. All the analysed samples, classified as extra virgin by the panel test, never present peaks whose magnitude is important enough in defected oils. The study was focused on the evaluation of volatile compounds responsible for the positive impact on olive odour properties ('green-fruity' and 'sweet') and olfactory perception. Chemometric evaluation of data, obtained through headspace analysis and the panel test evaluation, showed a correlation between chemical compounds and sensory properties. On the basis of the results, the positive attributes of virgin olive oil are divided into two separated groups: sweet types or green types. Sixteen volatile compounds with known positive impact on odour properties were extracted and identified. In particular, eight compounds seem correlated with sweet properties whereas the green sensation appears to be correlated with eight other different substances. The content of the compounds at six carbon atoms proves to be very important in defining positive attributes of extra virgin olive oils and sensory evaluation. © 2015
How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?
West, Brady T.; Sakshaug, Joseph W.; Aurelien, Guy Alain S.
2016-01-01
Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data. PMID:27355817
How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?
West, Brady T; Sakshaug, Joseph W; Aurelien, Guy Alain S
2016-01-01
Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data.
NASA Astrophysics Data System (ADS)
Carbillet, Marcel; Jolissaint, Laurent; Maire, Anne-Lise
We present the Software Package PAOLAC (“PAOLA within Caos”) in its first distributed version. This new numerical simulation tool is an embedment of the analytical adaptive optics simulation code PAOLA (“Performance of Adaptive Optics for Large (or Little) Apertures”) within the CAOS problem-solving environment. The main goal of this new tool is to allow an easier and direct comparison between studies performed with the analytical open-loop code PAOLA and studies performed with the end-to-end closed-loop Software Package CAOS (“Code for Adaptive Optics Systems”), with the final scope of better understanding how to take advantage from the two approaches: one analytical allowing extremely quick results on a wide range of cases and the other extremely detailed but with a computational and memory costs which can be impressive. The practical implementation of this embedment is briefly described, showing how this absolutely does not affect any aspect of the original code which is simply directly called from the CAOS global graphical interface through ad hoc modules. A comparison between end-to-end modelling and analytical modelling is hence also initiated, within the specific framework of wide-field adaptive optics at Dome C, Antarctica.
ERIC Educational Resources Information Center
Thorsland, Martin N.; Novak, Joseph D.
A study on individual differences in problem solving approach and their relationships to various learning-related parameters was conducted with a random sample of 25 subjects enrolled in an introductory physics course utilizing instruction through audio-tutorial methods. The subjects received interviews consisting of four problems in energy…
Stahl, Cynthia; Cimorelli, Alan
2013-01-01
Because controversy, conflict, and lawsuits frequently characterize US Environmental Protection Agency (USEPA) decisions, it is important that USEPA decision makers understand how to evaluate and then make decisions that have simultaneously science-based, social, and political implications. Air quality management is one category of multidimensional decision making at USEPA. The Philadelphia, Pennsylvania metropolitan area experiences unhealthy levels of ozone, fine particulate matter, and air toxics. Many ozone precursors are precursors for particulate matter and certain air toxics. Additionally, some precursors for particulate matter are air toxics. However, air quality management practices have typically evaluated these problems separately. This approach has led to the development of independent (and potentially counterproductive) implementation strategies. This is a methods article about the necessity and feasibility of using a clumsy approach on wicked problems, using an example case study. Air quality management in Philadelphia is a wicked problem. Wicked problems are those where stakeholders define or view the problem differently, there are many different ways to describe the problem (i.e., different dimensions or levels of abstraction), no efficient or optimal solutions exist, and they are often complicated by moral, political, or professional dimensions. The USEPA has developed the multicriteria integrated resource assessment (MIRA) decision analytic approach that engages stakeholder participation through transparency, transdisciplinary learning, and the explicit use of value sets; in other words, a clumsy approach. MIRA's approach to handling technical indicators, expert judgment, and stakeholder values makes it a potentially effective method for tackling wicked environmental problems. Copyright © 2012 SETAC.
Multiple steady states for characteristic initial value problems
NASA Technical Reports Server (NTRS)
Salas, M. D.; Abarbanel, S.; Gottlieb, D.
1984-01-01
The time dependent, isentropic, quasi-one-dimensional equations of gas dynamics and other model equations are considered under the constraint of characteristic boundary conditions. Analysis of the time evolution shows how different initial data may lead to different steady states and how seemingly anamolous behavior of the solution may be resolved. Numerical experimentation using time consistent explicit algorithms verifies the conclusions of the analysis. The use of implicit schemes with very large time steps leads to erroneous results.
Zatsiorsky, Vladimir M.
2011-01-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423–453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem. PMID:21311907
Terekhov, Alexander V; Zatsiorsky, Vladimir M
2011-02-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423-453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem.
Faller, H; Gossler, S
1998-05-01
The present paper has the objective of demonstrating the content-analytical assessment of problems reported by the patient and of his expectations in respect of psychotherapeutic treatment. In this approach of qualitative research, the interpretation process is split up into several steps which can be tested with regard to their adequacy to the material. This reduces the range of subjective interpretations. The development of the analysis of content is described in detail. First of all, a system of categories was outlined on the basis of patients' Nos. 1-40. This system was then used to rate the texts Nos. 41-80 and modified. After that, the revised version was applied to rate the texts Nos. 81-120, and so on. As can be shown, high interrater reliabilities were achieved by this procedure. The coding of the entire sample of n = 198 patient reports yielded the following results. Of all problems, depressive complaints, bodily complaints, anxiety and interpersonal problems were most frequent. The most important goals concerned coping with anxiety, gaining joy of living/happiness/satisfaction, greater self-assertion, better family relations/partnership, coping with problems and peace of mind/calmness. The categories of goals (18 items) seemed to be more complex and manifold than the categories of problems (10 items) and went beyond mere reduction of complaints or problems. As was to be expected, differences between diagnostic groups with regard to frequency of problems and expectations could be demonstrated. However, these differences were found only in the frequencies of deficits (complaints and problems) and reduction of complaints or coping with problems, respectively, whereas positive, health-related goals did not seem to be specific to the disorder. This suggests that it would be worth while to utilise patients' subjective definitions of problems and goals for assessment schedules to evaluate treatment outcomes.
Analytical solution of the contact problem for a system of bodies under collective wear
NASA Astrophysics Data System (ADS)
Soldatenkov, I. A.
2017-01-01
The contact problem is considered for a system of bodies subject to wear on a common base. The deformation properties of the bodies and the base are described by the Winkler model. The problem is reduced to a system of ordinary differential equations and an integral equation of hereditary type with difference kernel. The solution of the problem is constructed with the use of the Laplace transform. The asymptotics of the solution at large times is studied. The continuity conditions for the contact of each of the bodies with the base are derived.
Method of characteristics for the 3D perfect plasticity problem with the von Mises yield criterion
NASA Astrophysics Data System (ADS)
Verveyko, N. D.; Kuptsov, A. V.
2009-04-01
We present a linearized system of partial differential equations for the three-dimensional perfect plasticity problem with the von Mises yield criterion. We construct the characteristics of the three-dimensional problem, obtain differential relations along the characteristic planes, and devise a consistent stable finite-difference scheme. The use of conditions on the stress discontinuity surfaces permits simultaneously solving the Cauchy, Goursat, and mixed problems.
1991-01-15
This research project was to develop methods for the numerical and analytic analysis of implicit systems of differential equations, (DAE)- F(x’, z ,t...0 (1) which are not equivalent to an explicit ordinary differential equation (ODE), (ODE) z ’ = G( z , t) (2) That is, the Jacobian Fe of (1) is...structure theorems and a general numerical procedure for the linear time varying DAE E(t)w’(t) + F(t) z (t) = f(t) (3) This numerical algorithm was the
NASA Technical Reports Server (NTRS)
Gossard, Myron L
1952-01-01
An iterative transformation procedure suggested by H. Wielandt for numerical solution of flutter and similar characteristic-value problems is presented. Application of this procedure to ordinary natural-vibration problems and to flutter problems is shown by numerical examples. Comparisons of computed results with experimental values and with results obtained by other methods of analysis are made.
Some Problems of Rocket-Space Vehicles' Characteristics co- ordination
NASA Astrophysics Data System (ADS)
Sergienko, Alexander A.
2002-01-01
of the XX century suffered a reverse. The designers of the United States' firms and enterprises of aviation and rocket-space industry (Boeing, Rocketdyne, Lockheed Martin, McDonnell Douglas, Rockwell, etc.) and NASA (Marshall Space Flight Center, Johnson Space Center, Langley Research Center and Lewis Research Center and others) could not correctly co-ordinate the characteristics of a propulsion system and a space vehicle for elaboration of the "Single-Stage-To-Orbit" reusable vehicle (SSTO) as an integral whole system, which is would able to inject a payload into an orbit and to return back on the Earth. jet nozzle design as well as the choice of propulsion system characteristics, ensuring the high ballistic efficiency, are considered in the present report. The efficiency criterions for the engine and launch system parameters optimization are discussed. The new methods of the nozzle block optimal parameters' choice for the satisfaction of the object task of flight are suggested. The family of SSTO with a payload mass from 5 to 20 ton and initial weight under 800 ton is considered.
Clinical characteristics and surgical problems of ruptured globe injury.
Bi, Hongsheng; Cui, Yan; Li, Yang; Wang, Xingrong; Zhang, Jianhua
2013-06-01
Ocular trauma is a major cause of vision loss, especially in the young patients, and is the leading cause of unilateral blind in China. The aims of this report are to analyze ciliary and choroidal lesion characteristics and outcomes of a group of patients with ruptured globe injuries and discuss finding a more effective treatment protocol. Here we report our experience treating ruptured globe injuries. Seventy-five patients (75 eyes) with a diagnosis of ruptured globe injuries were selected from 264 patients with open globe injuries at the Shierming Eye Hospital of Shandong Province between January 2009 and December 2011. General information and clinical characteristics such as ciliary and choroidal lesion features were reviewed. Of the 75 patients, 85.3% were men, and the average age of the patients was 37.2 years (range, 6-63 years). The right eye was injured in 52.0%; enucleation was performed in 9 patients. There was no light perception, in the final corrected visual acuity in another 3 patients. The ratio of better visual acuity (better than 0.1) increased from 0 preoperatively to 16.0% postoperatively. Among the 75 patients with ruptured globe injuries, 13 had ciliary injury and 47 (62.7%) had choroidal injuries. Both ciliary and choroidal injuries were detected in 15 patients. Retinal tissue incarceration during sclera suturing was usually the vital point leading to unfavorable results. Ruptured globe injury usually results in severe visual acuity damage. Active treatment could help to restore visual acuity in patients to some degree. Some effective treatment protocols for ruptured globe injuries could be followed. Some unsuitable procedures in primary treatment should be avoided to achieve a better prognosis.
Clinical Characteristics and Surgical Problems of Ruptured Globe Injury☆
Bi, Hongsheng; Cui, Yan; Li, Yang; Wang, Xingrong; Zhang, Jianhua
2013-01-01
Background Ocular trauma is a major cause of vision loss, especially in the young patients, and is the leading cause of unilateral blind in China. Objective The aims of this report are to analyze ciliary and choroidal lesion characteristics and outcomes of a group of patients with ruptured globe injuries and discuss finding a more effective treatment protocol. Here we report our experience treating ruptured globe injuries. Methods Seventy-five patients (75 eyes) with a diagnosis of ruptured globe injuries were selected from 264 patients with open globe injuries at the Shierming Eye Hospital of Shandong Province between January 2009 and December 2011. General information and clinical characteristics such as ciliary and choroidal lesion features were reviewed. Results Of the 75 patients, 85.3% were men, and the average age of the patients was 37.2 years (range, 6–63 years). The right eye was injured in 52.0%; enucleation was performed in 9 patients. There was no light perception, in the final corrected visual acuity in another 3 patients. The ratio of better visual acuity (better than 0.1) increased from 0 preoperatively to 16.0% postoperatively. Among the 75 patients with ruptured globe injuries, 13 had ciliary injury and 47 (62.7%) had choroidal injuries. Both ciliary and choroidal injuries were detected in 15 patients. Retinal tissue incarceration during sclera suturing was usually the vital point leading to unfavorable results. Conclusions Ruptured globe injury usually results in severe visual acuity damage. Active treatment could help to restore visual acuity in patients to some degree. Some effective treatment protocols for ruptured globe injuries could be followed. Some unsuitable procedures in primary treatment should be avoided to achieve a better prognosis. PMID:24385006
Sexual problems and post-traumatic stress disorder following sexual trauma: A meta-analytic review.
O'Driscoll, Ciarán; Flanagan, Esther
2016-09-01
Difficulties with sex often develop following sexual trauma, yet are rarely targeted within treatment of post-traumatic stress disorder (PTSD). Where outcomes of sexual function are included, they are secondary to other measures. This review aimed to assess whether psychological treatment for PTSD (from sexual trauma) has an effect on sexual functioning. Systematic searches of MEDLINE, PsycINFO, EMBASE, and trial registers were performed. Five studies met inclusion criteria. Pre-post treatment effect sizes were also calculated. Data from four good-quality RCTs were included in the meta-analyses. These examined females (n = 799) who had experienced adult sexual trauma or child sexual abuse. Studies compared psychological treatment to control conditions, but no effect on outcomes of sexual concerns, standardized mean difference (SMD) = 0.03 and dysfunctional sexual behaviour, SMD = 0.02, was found. Pre-post treatment effect sizes were small to medium (SMD = 0.36 and 0.47, respectively). While firm conclusions cannot be drawn, the available evidence suggests that psychological treatment for PTSD has no effect on sexual problems. Pre-post effects indicate some improvement over the course of treatment, which may be strengthened if treatment actively targeted sexual problems. The paucity of evidence in this area suggests that there is substantial need for further research in order to establish a set of evidence-based guidelines for practitioners implementing treatment in this area. The measurement of sexual problems is overlooked in psychological treatment RCTs for sexual trauma. Current treatments for post-traumatic stress disorder (PTSD) from sexual trauma do not appear to be addressing sexual problems. Integrated treatments for comorbid sexual problems and PTSD treatment may be warranted. It is imperative that in future, RCTs that examine people with PTSD from sexual trauma use outcomes of sexual problems. © 2015 The British Psychological Society.
The analytic solution of the structural analysis problem and its use in structural synthesis
NASA Astrophysics Data System (ADS)
Fuchs, M. B.
An overview is presented of the analytic expressions for the inverse of the stiffness matrix, the nodal displacements, and the internal forces in linear elastic redundant structures. The inverse of the stiffness matrix and the nodal displacements are obtained using Binet and Cauchy's theorem on the product of compound matrices. The formula for the internal forces is derived from the principles of structural mechanics. This approach is shown to apply to all framed structures via the unimodal stiffnesses of its elements. Approximate models are constructed which are exact at preselected points along a line in the analysis space. An argument is also made for the use of multilinear polynomials as an alternative to Taylor expansion-based approximations.
Exact analytical solution to a transient conjugate heat-transfer problem
NASA Technical Reports Server (NTRS)
Sucec, J.
1973-01-01
An exact analytical solution is found for laminar, constant-property, slug flow over a thin plate which is also convectively cooled from below. The solution is found by means of two successive Laplace transformations when a transient in the plate and the fluid is initiated by a step change in the fluid inlet temperature. The exact solution yields the transient fluid temperature, surface heat flux, and surface temperature distributions. The results of the exact transient solution for the surface heat flux are compared to the quasi-steady values, and a criterion for the validity of the quasi-steady results is found. Also the effect of the plate coupling parameter on the surface heat flux are investigated.
Kuznetsov, A V
2013-01-01
The purpose of this paper was to develop an analytical solution describing retrograde transport of nerve growth factors (NGFs) from a target tissue to the neuron soma. The obtained solution is applied to describe two situations: (1) when all dynein motors are moving at a constant velocity and (2) when the dynein velocity distribution is described by a probability density function. The dynamics of NGF concentrations and fluxes is investigated. It is established that the magnitude of the diffusion flux forms a wave localised in space and propagating towards the neuron soma; the magnitude of this wave decreases as the wave propagates downstream. The dynein-driven flux of NGFs is demonstrated to be the main component in the NGF flux, which is shown to be strongly correlated with the NGF concentration.
Remote Estimation of Crop Biophysical Characteristics: Problems and Solutions
NASA Astrophysics Data System (ADS)
Gitelson, A. A.; Rundquist, D. C.; Keydan, G. P.
2007-12-01
Characterization of crop physiological and phenological status, or crop condition, requires robust retrievals of important crop biophysical properties, preferably using non-destructive methods. The sensitivity of the widely used Normalized Difference Vegetation Index (NDVI) saturates at moderate levels of aboveground biomass; i.e., when leaf area index (LAI) increases above about 2. We report the results of our investigation of the performance of an advanced suite of four vegetation indices that expand the dynamic ranges of canopy biophysical properties over high biomass surfaces. The indices are: 1) the Visible Atmospherically Resistant Vegetation Index (VARI), for retrieving the fractional cover of green vegetation; 2) the Wide Dynamic Range Vegetation Index (WDRVI), which allows retrieval of LAI: 3) the Green NDVI and Red Edge NDVI, designed to yield the photosynthetically active component of total absorbed photosynthetically active radiation (fAPAR); and 4) Green and Red Edge Chlorophyll Indices for measuring the total chlorophyll content in a vegetation canopy. We discuss the results of estimating the biophysical characteristics noted above using close range sensing (reflectance taken 6 meters above the canopy), an airborne imaging spectrometer and satellite observations. The techniques were tested for maize and soybean in agricultural fields under irrigated and rainfed conditions. It is possible to accurately estimate the fractional cover of green vegetation, the photosynthetically active component of absorbed PAR, green LAI and chlorophyll content in crops with different canopy architectures and leaf structures with green leaf area indices ranging from 0 to more than 6.
ERIC Educational Resources Information Center
Comer, Jonathan S.; Chow, Candice; Chan, Priscilla T.; Cooper-Vince, Christine; Wilson, Lianna A. S.
2013-01-01
Objective: Service use trends showing increased off-label prescribing in very young children and reduced psychotherapy use raise concerns about quality of care for early disruptive behavior problems. Meta-analysis can empirically clarify best practices and guide clinical decision making by providing a quantitative synthesis of a body of…
ERIC Educational Resources Information Center
van Rooij, Iris; Schactman, Alissa; Kadlec, Helena; Stege, Ulrike
2006-01-01
The Euclidean Traveling Salesperson Problem (E-TSP) is a useful task to study how humans optimize when faced with computational intractability. It has been found that humans are capable of finding high-quality solutions for E-TSP in a relatively short time and with seemingly little cognitive effort. This observation has led to two general…
Some Analytical Results for the Dynamic Weapon-Target Allocation Problem
1990-02-04
and presents some numerical results in [7]. Matlin [91 provides a review of the literature on weapon-target allocation problems. Several references are...is NP-Complete," in Proceedings of the 1986 Summer Conference on Simulation, (Reno, Nevada), July 1986. [9] Matlin , S. M., "A Review of the
Firing the Executive: When an Analytic Approach to Problem Solving Helps and Hurts
ERIC Educational Resources Information Center
Aiello, Daniel A.; Jarosz, Andrew F.; Cushen, Patrick J.; Wiley, Jennifer
2012-01-01
There is a general assumption that a more controlled or more focused attentional state is beneficial for most cognitive tasks. However, there has been a growing realization that creative problem solving tasks, such as the Remote Associates Task (RAT), may benefit from a less controlled solution approach. To test this hypothesis, in a 2x2 design,…
Educational Reform as a Dynamic System of Problems and Solutions: Towards an Analytic Instrument
ERIC Educational Resources Information Center
Luttenberg, Johan; Carpay, Thérèse; Veugelers, Wiel
2013-01-01
Large-scale educational reforms are difficult to realize and often fail. In the literature, the course of reform and problems associated with this are frequently discussed. The explanations and recommendations then provided are so diverse that it is difficult to gain a comprehensive overview of what factors are at play and how to take them into…
Firing the Executive: When an Analytic Approach to Problem Solving Helps and Hurts
ERIC Educational Resources Information Center
Aiello, Daniel A.; Jarosz, Andrew F.; Cushen, Patrick J.; Wiley, Jennifer
2012-01-01
There is a general assumption that a more controlled or more focused attentional state is beneficial for most cognitive tasks. However, there has been a growing realization that creative problem solving tasks, such as the Remote Associates Task (RAT), may benefit from a less controlled solution approach. To test this hypothesis, in a 2x2 design,…
ERIC Educational Resources Information Center
Comer, Jonathan S.; Chow, Candice; Chan, Priscilla T.; Cooper-Vince, Christine; Wilson, Lianna A. S.
2013-01-01
Objective: Service use trends showing increased off-label prescribing in very young children and reduced psychotherapy use raise concerns about quality of care for early disruptive behavior problems. Meta-analysis can empirically clarify best practices and guide clinical decision making by providing a quantitative synthesis of a body of…
ERIC Educational Resources Information Center
Durand, V. Mark; Merges, Eileen
2001-01-01
This article describes functional communication training (FCT) with students who have autism. FCT involves teaching alternative communication strategies to replace problem behaviors. The article reviews the conditions under which this intervention is successful and compares the method with other behavioral approaches. It concludes that functional…
Educational Reform as a Dynamic System of Problems and Solutions: Towards an Analytic Instrument
ERIC Educational Resources Information Center
Luttenberg, Johan; Carpay, Thérèse; Veugelers, Wiel
2013-01-01
Large-scale educational reforms are difficult to realize and often fail. In the literature, the course of reform and problems associated with this are frequently discussed. The explanations and recommendations then provided are so diverse that it is difficult to gain a comprehensive overview of what factors are at play and how to take them into…
ERIC Educational Resources Information Center
van Rooij, Iris; Schactman, Alissa; Kadlec, Helena; Stege, Ulrike
2006-01-01
The Euclidean Traveling Salesperson Problem (E-TSP) is a useful task to study how humans optimize when faced with computational intractability. It has been found that humans are capable of finding high-quality solutions for E-TSP in a relatively short time and with seemingly little cognitive effort. This observation has led to two general…
NASA Astrophysics Data System (ADS)
Hayek, Mohamed; Kosakowski, Georg; Churakov, Sergey
2011-07-01
We present exact analytical solutions for a one-dimensional diffusion problem coupled with the precipitation-dissolution reaction ? and feedback of porosity change. The solutions are obtained in the form of traveling waves and describe spatial and temporal evolutions of solute concentration, porosity, and mineral distribution for a set of initial and boundary conditions. The form of the solutions limits the choice of admissible boundary conditions, which might be difficult to adapt in natural systems, and thus, the solutions are of limited use for such a system. The main application of the derived solutions is therefore the benchmarking of numerical reactive transport codes for systems with strong porosity change. To test the performance of numerical codes, numerical solutions obtained by using a global implicit finite volume technique are compared to the analytical solutions. Good agreement is obtained between the analytical solutions and the numerical solutions when a sufficient spatial discretization resolves the spatial concentration gradients at any time. In the limit of fast kinetics (local equilibrium), steep concentration fronts cannot be resolved in a numerical discretization schema.
Lu, Zhengang; Tan, Jiubin
2008-10-10
The transmitting characteristics of high-transparency double-layer metallic meshes with submillimeter period were analyzed using an analytical model, which was established using angular spectrum propagation theory and verified through experiments. It was found through analysis that rotating misalignment has significant effect on the distribution of diffraction spot intensity. Large period and small linewidth can be used to obtain high transmittance and low levels of stray light. Substrate thickness has little effect on transmitting characteristics of mesh, and so it is a variable free to choose in optimizing shielding characteristics of mesh. We think, together with other ways and means of optimizing shielding characteristics of mesh, the model can also be used for the optimization of a high-pass mesh filter.
NASA Technical Reports Server (NTRS)
Fuller, C. R.
1986-01-01
A simplified analytical model of transmission of noise into the interior of propeller-driven aircraft has been developed. The analysis includes directivity and relative phase effects of the propeller noise sources, and leads to a closed form solution for the coupled motion between the interior and exterior fields via the shell (fuselage) vibrational response. Various situations commonly encountered in considering sound transmission into aircraft fuselages are investigated analytically and the results obtained are compared to measurements in real aircraft. In general the model has proved successful in identifying basic mechanisms behind noise transmission phenomena.
NASA Technical Reports Server (NTRS)
Carden, H. D.
1974-01-01
Experimental and analytical natural frequencies, nodal patterns, and typical modal displacements for a corrugated, flexibly supported, heat-shield panel are discussed. Good correlation was found between the experimental data and NASTRAN analytical results for the corrugated panel over a relatively wide frequency spectrum covered in the investigation. Of the two experimental techniques used for mode shape and displacement measurements (a noncontacting displacement sensor system and a holographic technique using a helium-neon, continuous-wave laser), the holographic technique was found, in the present investigation, to be faster and better suited for determining a large number of complex nodal patterns of the corrugated panel.
A protocol-analytic study of metacognition in mathematical problem solving
NASA Astrophysics Data System (ADS)
Cai, Jinfa
1994-12-01
The metacognitive behaviours of two subjects having a high level of mathematical experience and two subjects having a low level of mathematical experience were compared within each of the four cognitive processes of mathematical problem solving: orientation, organisation, execution, and verification. The results showed that the high-experience subjects engaged in self-regulation during the problem-solving process and that the low-experience subjects did not. Also, the high-experience subjects had stronger awareness about what they knew and how they should use this knowledge, and were able to sequentially monitor their goal-changing and decision-making activities in order to implement their goal. Another important finding was that the high-experience subjects spent the majority of their time on orientation and organisation rather than on execution, while low-experience subjects spent the majority of their time on execution rather than on orientation and organisation. Finally, the high-experience subjects accurately evaluated their strategies, actions and intermediate results. The results suggest that individual differences between the high- and low-experience subjects are unlikely to emerge either from the subjects' selection of solution strategies or from the level of mathematical knowledge required for solving the problem. Therefore, the results from this study support the argument that metacognitive behaviours have important influences on subjects' problem-solving success. This study also suggests that a complex, difficult, or novel task appears to function well as a task for examining metacognitive behaviours because such a task results in the subjects being unable to arrive at closure quickly.
Analytical solution of the problem of a shock wave in the collapsing gas in Lagrangian coordinates
NASA Astrophysics Data System (ADS)
Kuropatenko, V. F.; Shestakovskaya, E. S.
2016-10-01
It is proposed the exact solution of the problem of a convergent shock wave and gas dynamic compression in a spherical vessel with an impermeable wall in Lagrangian coordinates. At the initial time the speed of cold ideal gas is equal to zero, and a negative velocity is set on boundary of the sphere. When t > t0 the shock wave spreads from this point into the gas. The boundary of the sphere will move under the certain law correlated with the motion of the shock wave. The trajectories of the gas particles in Lagrangian coordinates are straight lines. The equations determining the structure of the gas flow between the shock front and gas border have been found as a function of time and Lagrangian coordinate. The dependence of the entropy on the velocity of the shock wave has been found too. For Lagrangian coordinates the problem is first solved. It is fundamentally different from previously known formulations of the problem of the self-convergence of the self-similar shock wave to the center of symmetry and its reflection from the center, which was built up for the infinite area in Euler coordinates.
NASA Astrophysics Data System (ADS)
Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, AL
2014-01-01
The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking ability of students in both the treatment and control groups were evaluated before and at the end of the implementation of the programme, using the Torrance Tests of Creative Thinking. In addition, changes in students' self-regulated learning skills using the Self-Regulated Learning Interview Schedule (SRLIS) and their self-evaluation proficiency were evaluated. Analysis of covariance showed that the creative thinking ability of the treatment group had improved statistically significantly after the PBL course (p < 0.001) compared to that of the students in the comparison group. PBL was shown to have a positive effect on creative thinking ability. The SRLIS test showed that students in the treatment group used self-regulated learning strategies more frequently than students in the comparison group. According to the results of the self-evaluation, students became more positive and confident in problem-solving and group work as the semester progressed. Overall, PBL was shown to be an effective pedagogical instructional strategy for enhancing chemistry students' creative thinking ability, self-regulated learning skills and self-evaluation.
Spencer, Steven J
2010-05-01
Closed-form analytical solutions are found for the time difference of arrival (TDOA) source location problem. Solutions are found for both two-dimensional (2D) and three-dimensional (3D) source location by formulating the TDOA equations in, respectively, polar and spherical coordinate systems, with the radial direction coincident with the assumed geodesic path of signal propagation to a reference sensor. Quadratic equations for TDOA 2D and 3D source location based on the spherical intersection (SX) scheme, in some cases permitting dual physical solutions, are found for three and four sensor element monitoring arrays, respectively. A method of spherical intersection subarrays (SXSAs) is developed to derive from these quadratic equations globally unique closed-form analytical solutions for TDOA 2D and 3D source location, for four and five sensor element monitoring arrays, respectively. Errors in 2D source location for introduced bias in time differences of arrival are shown to have a strong geometrical dependence. The SXSA and SX methods perform well in terms of accuracy and precision at high levels of arrival time bias for both 2D and 3D source location and are much more efficient than nonlinear least-squares schemes. The SXSA scheme may have particular applicability to accurately solving source location problems in demanding real-time situations.
Goals and Characteristics of Long-Term Care Programs: An Analytic Model.
ERIC Educational Resources Information Center
Braun, Kathryn L.; Rose, Charles L.
1989-01-01
Used medico-social analytic model to compare five long-term care programs: Skilled Nursing Facility-Intermediate Care Facility (SNF-ICF) homes, ICF homes, foster homes, day hospitals, and home care. Identified similarities and differences among programs. Preliminary findings suggest that model is useful in the evaluation and design of long-term…
Fitting of dihedral terms in classical force fields as an analytic linear least-squares problem.
Hopkins, Chad W; Roitberg, Adrian E
2014-07-28
The derivation and optimization of most energy terms in modern force fields are aided by automated computational tools. It is therefore important to have algorithms to rapidly and precisely train large numbers of interconnected parameters to allow investigators to make better decisions about the content of molecular models. In particular, the traditional approach to deriving dihedral parameters has been a least-squares fit to target conformational energies through variational optimization strategies. We present a computational approach for simultaneously fitting force field dihedral amplitudes and phase constants which is analytic within the scope of the data set. This approach completes the optimal molecular mechanics representation of a quantum mechanical potential energy surface in a single linear least-squares fit by recasting the dihedral potential into a linear function in the parameters. We compare the resulting method to a genetic algorithm in terms of computational time and quality of fit for two simple molecules. As suggested in previous studies, arbitrary dihedral phases are only necessary when modeling chiral molecules, which include more than half of drugs currently in use, so we also examined a dihedral parametrization case for the drug amoxicillin and one of its stereoisomers where the target dihedral includes a chiral center. Asymmetric dihedral phases are needed in these types of cases to properly represent the quantum mechanical energy surface and to differentiate between stereoisomers about the chiral center.
NASA Astrophysics Data System (ADS)
Holman, Benjamin R.
In recent years, revolutionary "hybrid" or "multi-physics" methods of medical imaging have emerged. By combining two or three different types of waves these methods overcome limitations of classical tomography techniques and deliver otherwise unavailable, potentially life-saving diagnostic information. Thermoacoustic (and photoacoustic) tomography is the most developed multi-physics imaging modality. Thermo- and photo- acoustic tomography require reconstructing initial acoustic pressure in a body from time series of pressure measured on a surface surrounding the body. For the classical case of free space wave propagation, various reconstruction techniques are well known. However, some novel measurement schemes place the object of interest between reflecting walls that form a de facto resonant cavity. In this case, known methods cannot be used. In chapter 2 we present a fast iterative reconstruction algorithm for measurements made at the walls of a rectangular reverberant cavity with a constant speed of sound. We prove the convergence of the iterations under a certain sufficient condition, and demonstrate the effectiveness and efficiency of the algorithm in numerical simulations. In chapter 3 we consider the more general problem of an arbitrarily shaped resonant cavity with a non constant speed of sound and present the gradual time reversal method for computing solutions to the inverse source problem. It consists in solving back in time on the interval [0, T] the initial/boundary value problem for the wave equation, with the Dirichlet boundary data multiplied by a smooth cutoff function. If T is sufficiently large one obtains a good approximation to the initial pressure; in the limit of large T such an approximation converges (under certain conditions) to the exact solution.
Analytical solution of the optimal three dimensional reentry problem using Chapman's exact equations
NASA Technical Reports Server (NTRS)
Vinh, N. X.; Busemann, A.; Culp, R. D.
1974-01-01
This paper presents the general solution for the optimal three dimensional aerodynamic control of a lifting vehicle entering a planetary atmosphere. A set of dimensionless variables is introduced, and the resulting exact equations of motion have the distinctive advantage that they are completely free of the physical characteristics of the vehicle. Furthermore, a general lift-drag polar is used to define the aerodynamic control. Hence, the results obtained apply to any type of vehicle of arbitrary weight, dimensions and shape, having an arbitrary polar and entering any planetary atmosphere.
Analytical solution of the optimal three dimensional reentry problem using Chapman's exact equations
NASA Technical Reports Server (NTRS)
Vinh, N. X.; Busemann, A.; Culp, R. D.
1974-01-01
This paper presents the general solution for the optimal three dimensional aerodynamic control of a lifting vehicle entering a planetary atmosphere. A set of dimensionless variables is introduced, and the resulting exact equations of motion have the distinctive advantage that they are completely free of the physical characteristics of the vehicle. Furthermore, a general lift-drag polar is used to define the aerodynamic control. Hence, the results obtained apply to any type of vehicle of arbitrary weight, dimensions and shape, having an arbitrary polar and entering any planetary atmosphere.
Semi-analytical solution to the 2014 eddy current benchmark problem
NASA Astrophysics Data System (ADS)
Miorelli, Roberto; Reboud, Christophe; Voulgaraki, Charitini; Poulakis, Nikolaos; Theodoulidis, Theodoros
2015-03-01
This work proposes a solution to the 2014 eddy current testing benchmark, published by the WFNDEC and proposed by the authors. The aim of this benchmark is to provide reference data for eddy current testing configurations involving magnetic sensors -here Hall sensors- as receivers, as they present some advantages in terms of resolution and sensitivity. After a presentation of the benchmark cases, the theoretical approach used to solve the equivalent electromagnetic problem is detailed and a alternative computation of eddy current signals is proposed. Then, simulations are quantitatively compared to experimental data in each case and the results are discussed.
Application of Advanced Decision-Analytic Technology to Rapid Deployment Joint Task Force Problems
1981-06-01
60 4 E F I T 20 0 2U 40 60 s0 100 CO3T Figure A-1 BENEFIT/COST CURVE A-4 This is not an approach that DDI uses unilaterally to study and recommend...UNCLASSIFIED SICURITv CLAS.IPICATION OP TNIS PA@e(hm bets goIu .... useful product in the near term. This problem concerned the provision of an...construction programs, permit rapid ex- ploration of the usefulness of new proposed base options, and add to under- standing whether and how decision
A general analytical solution to the geometrical problem of field matching in radiotherapy.
Hernandez, V; Arenas, M; Pons, F; Sempau, J
2009-09-01
Several authors studied the problem of geometrical matching of fields produced by medical linear accelerators. However, a general solution has yet to be published. Currently available solutions are based on parallelism arguments. This study provides a general solution, considering not only parallelism but also field sizes. A fixed field with arbitrary field size, gantry, collimator, and couch angle is considered, and another field with a fixed gantry angle is matched to it. A single reference system attached to the treatment couch is used, and two approaches are followed. In the first approach, fixed field sizes are assumed and parallelism of the adjacent field-side planes is imposed. In the second approach, fixed isocenter positions are considered and both parallelism and coincidence between field-side planes are required. When fixed field sizes are assumed, rotation angles are obtained; however, the isocenters may need to be shifted to make side planes coincident and therefore achieve a proper match. When fixed isocenter positions are considered, solutions for all parameters, including the field size, are obtained and an exact geometrical match is achieved. General expressions to the field-matching problem are found for the two approaches followed, fixed field sizes, and fixed isocenter positions. These results can be applied to any treatment technique and can easily be implemented in modern treatment planning systems.
A general analytical solution to the geometrical problem of field matching in radiotherapy
Hernandez, V.; Arenas, M.; Pons, F.; Sempau, J.
2009-09-15
Purpose: Several authors studied the problem of geometrical matching of fields produced by medical linear accelerators. However, a general solution has yet to be published. Currently available solutions are based on parallelism arguments. This study provides a general solution, considering not only parallelism but also field sizes. Methods: A fixed field with arbitrary field size, gantry, collimator, and couch angle is considered, and another field with a fixed gantry angle is matched to it. A single reference system attached to the treatment couch is used, and two approaches are followed. In the first approach, fixed field sizes are assumed and parallelism of the adjacent field-side planes is imposed. In the second approach, fixed isocenter positions are considered and both parallelism and coincidence between field-side planes are required. Results: When fixed field sizes are assumed, rotation angles are obtained; however, the isocenters may need to be shifted to make side planes coincident and therefore achieve a proper match. When fixed isocenter positions are considered, solutions for all parameters, including the field size, are obtained and an exact geometrical match is achieved. Conclusions: General expressions to the field-matching problem are found for the two approaches followed, fixed field sizes, and fixed isocenter positions. These results can be applied to any treatment technique and can easily be implemented in modern treatment planning systems.
Baldessari, Fabio; Leal, L Gary
2005-09-01
We solve the problem of the creeping motion of a uniaxial extensional flow past two touching spherical drops when the line of centers is parallel to the axis of symmetry of the flow, using tangent sphere coordinates. We apply this solution to the case of two equal size drops. It provides an exact result for the equal and opposite force acting on each drop along the line of centers. We also use it to determine the magnitude of the internal recirculating flow in the vicinity of the rear stagnation point, which can be used to evaluate the importance of this flow on the film drainage process for two (nearly) touching drops in a coalescence process for the limiting case, Ca < 1.
Vertex cover problem studied by cavity method: Analytics and population dynamics
NASA Astrophysics Data System (ADS)
Zhou, Haijun
2003-03-01
We study the vertex cover problem on finite connectivity random graphs by zero-temperature cavity method. The minimum vertex cover corresponds to the ground state(s) of a proposed Ising spin model. When the connectivity c > e = 2.718282, there is no state for this system as the reweighting parameter y, which takes a similar role as the inverse temperature β in conventional statistical physics, approaches infinity; consequently the ground state energy is obtained at a finite value of y when the free energy function attains its maximum value. The minimum vertex cover size at given c is estimated using population dynamics and compared with known rigorous bounds and numerical results. The backbone size is also calculated.
NASA Technical Reports Server (NTRS)
Purvis, C. K.; Stevens, N. J.; Oglebay, J. C.
1977-01-01
A one-dimensional model for charging of samples is used in conjunction with experimental data taken to develop material charging characteristics for silvered Teflon. These characteristics are then used in a one dimensional model for charging in space to examine expected response. Relative charging rates as well as relative charging levels for silvered Teflon and metal are discussed.
ERIC Educational Resources Information Center
Trinter, Christine P.; Moon, Tonya R.; Brighton, Catherine M.
2015-01-01
The purpose of this qualitative study was to provide empirical evidence of the extent to which the types of tasks recommended by Sheffield for eliciting characteristics of mathematical promise allowed for the manifestation of these characteristics in primary-grade students within a problem-based learning (PBL) context. Data included student work…
ERIC Educational Resources Information Center
Orme, John G.; Buehler, Cheryl
2001-01-01
Reviews the literature on the foster family characteristics that are thought to contribute to the behavioral and emotional problems of foster children. The review is shaped by an understanding of the personal and familial factors associated with children's problem behaviors. Factors include parenting, family home environment, family functioning,…
Peer and Parenting Characteristics of Boys and Girls with Subclinical Attention Problems
ERIC Educational Resources Information Center
Rielly, Nicole E.; Craig, Wendy M.; Parker, Kevin C. H.
2006-01-01
Objective: This study examines peer and parenting characteristics of 149 boys and girls with and without subclinical attention problems. Method: Multivariate analyses showed that children with attention problems had higher levels of negative peer nominations and conflict and betrayal in friendships, and their parents tended to use higher levels of…
NASA Astrophysics Data System (ADS)
Cozzolino, Luca; Cimorelli, Luigi; Covelli, Carmine; Della Morte, Renata; Pianese, Domenico
2015-06-01
The general solution of the dam-break problem with partial uplift of the sluice-gate is presented in the framework of the one-dimensional Shallow-Water Equations, under the hypothesis that the classic Energy-Momentum (E-M) formulation is used to evaluate the flow characteristics at the gate. Due to the nonlinearity of the problem, there are ranges of the initial conditions for which the problem admits multiple solutions, or no solution. In the ranges in which there are multiple solutions, the maximization of the discharge under the gate is used as a disambiguation criterion. The exact solutions are used as a benchmark in order to evaluate the results of a simple Finite-Volume scheme, where the discharge under the gate and the forces exerted on the flow by the gate itself are calculated using the E-M formulation.
Language Problems Among Abused and Neglected Children: A Meta-Analytic Review.
Sylvestre, Audette; Bussières, Ève-Line; Bouchard, Caroline
2016-02-01
Research data show that exposure to abuse and neglect has detrimental effects on a child's language development. In this meta-analysis, we analyze studies (k = 23), to compare the language skills (receptive language, expressive language, pragmatics) of children who have experienced abuse and/or neglect with the language skills of children who have not experienced abuse and/or neglect and to examine whether age or type of maltreatment moderate the relationship between maltreatment and language skills. Results confirm that the language skills of children who have experienced abuse and/or neglect are delayed when compared to children who have not experienced abuse and/or neglect. Compared to older children, young children seem particularly vulnerable to abuse and neglect. No significant differences were demonstrated concerning the type of maltreatment suffered by the child. These findings support the necessity of early detection of language problems in abused and neglected children as well as early intervention in order to implement interventions that will positively stimulate their development. © The Author(s) 2015.
Analytic model to estimate thermonuclear neutron yield in z-pinches using the magnetic Noh problem
NASA Astrophysics Data System (ADS)
Allen, Robert C.
The objective was to build a model which could be used to estimate neutron yield in pulsed z-pinch experiments, benchmark future z-pinch simulation tools and to assist scaling for breakeven systems. To accomplish this, a recent solution to the magnetic Noh problem was utilized which incorporates a self-similar solution with cylindrical symmetry and azimuthal magnetic field (Velikovich, 2012). The self-similar solution provides the conditions needed to calculate the time dependent implosion dynamics from which batch burn is assumed and used to calculate neutron yield. The solution to the model is presented. The ion densities and time scales fix the initial mass and implosion velocity, providing estimates of the experimental results given specific initial conditions. Agreement is shown with experimental data (Coverdale, 2007). A parameter sweep was done to find the neutron yield, implosion velocity and gain for a range of densities and time scales for DD reactions and a curve fit was done to predict the scaling as a function of preshock conditions.
Transport synthetic acceleration for long-characteristics assembly-level transport problems
Zika, M.R.; Adams, M.L.
2000-02-01
The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authors devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly.
A Simple Analytical Approach to the Aeroelastic Stability Problem of Long-Span Cable-Stayed Bridges
NASA Astrophysics Data System (ADS)
Vairo, Giuseppe
2010-01-01
This paper deals with the aeroelastic stability problem of long-span cable-stayed bridges under an approaching crosswind flow. Starting from a continuous model of the fan-shaped bridge scheme with both H- or A-shaped towers, critical states of the coupled wind-structure system are identified by means of a variational formulation, accounting for torsional and flexural (vertical and lateral) bridge oscillations. The overall bridge dynamics is described by introducing simple mechanical systems with equivalent stiffness properties and, under the assumption of a prevailing truss-like bridge behavior, analytical estimates for dominant stiffness contributions are proposed. Several case studies are discussed and comparisons with experimental evidences as well as with available analytical and numerical results are presented. The proposed simplified approach proves to be consistent and effective for successfully capturing the main wind-bridge interaction mechanisms, and it could be considered as a useful engineering tool for the aeroelastic stability analysis of long-span cable-stayed bridges.
NASA Astrophysics Data System (ADS)
Stoyanov, D. G.
2007-11-01
The elementary processes taking place in the formation of charged particles and their flow in parallel-plane, cylindrical and spherical geometry cases of ionization chamber are considered. On the basis of particles and charges balance a differential equation describing the distribution of current densities in the ionization chamber volume is obtained. As a result of the differential equation solution an analytical form of the current-voltage characteristic of an ionization chamber with homogeneous ionization is obtained. For the parallel-plane case comparision with experimental data is performed.
Characteristics of the boundary-layer equations of the minimum time-to-climb problem
NASA Technical Reports Server (NTRS)
Ardema, M. D.
1976-01-01
In many singular perturbation solutions of optimal control problems, the most difficult numerical task is to solve the boundary-layer equations. However, these equations have a special structure that may often be used to expedite their solution. This paper begins by noting the general nature of the boundary-layer equations for optimal control problems. These results are then applied to the aircraft minimum time-to-climb problem. A specific numerical example is considered to illustrate the characteristics of the solution of the boundary-layer equations for this problem.
Mercado-Borrayo, B M; Schouwenaars, R; González-Chávez, J L; Ramírez-Zamora, R M
2013-01-01
A multi-analytical approach was used to develop a mathematical regression model to calculate the residual concentration of borate ions in water present at high initial content, as a function of the main physicochemical, mineralogical and electrokinetic characteristics after adsorption on five different types of iron and steel slag. The analytical techniques applied and slag properties obtained in this work were: X-ray Fluorescence for the identification of the main chemical compounds, X-ray Diffraction to determine crystalline phases, physical adsorption of nitrogen for the quantification of textural properties and zeta-potential for electrokinetic measurements of slag particles. Adsorption tests were carried out using the bottle-point technique and a highly concentrated borate solution (700 mg B/L) at pH 10, with a slag dose of 10 g/L. An excellent correlation between the residual concentration of boron and three independent variables (content of magnesium oxide, zeta potential and specific surface area) was established for the five types of slag tested in this work. This shows that the methodology based on a multi-analytical approach is a very strong and useful tool to estimate the performance of iron and steel slag as adsorbent of metalloids.
NASA Technical Reports Server (NTRS)
Purvis, C. K.; Stevens, N. J.; Oglebay, J. C.
1977-01-01
An understanding of the behavior of materials, of dielectrics in particular, under charged particle bombardment is essential to the prediction and prevention of the adverse effects of spacecraft charging. A one-dimensional model for charging of samples in a test facility was used in conjunction with experimental data taken to develop "material charging characteristics" for silvered Teflon. These characteristics were then used in a one-dimensional model for charging in space to examine expected response. Relative charging rates as well as relative charging levels for silvered Teflon and metal are discussed.
Test-Taker Characteristics and Integrated Speaking Test Performance: A Path-Analytic Study
ERIC Educational Resources Information Center
Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan; Hong, He-Ting Vivian
2016-01-01
This study explored the relationships among language proficiency, two selected test-taker characteristics (i.e., topical knowledge and anxiety), and integrated speaking test performance. Data collection capitalized on three sets of instruments: three integrated tasks derived from TOEFL-iBT preparation materials, the state anxiety inventory created…
Test-Taker Characteristics and Integrated Speaking Test Performance: A Path-Analytic Study
ERIC Educational Resources Information Center
Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan; Hong, He-Ting Vivian
2016-01-01
This study explored the relationships among language proficiency, two selected test-taker characteristics (i.e., topical knowledge and anxiety), and integrated speaking test performance. Data collection capitalized on three sets of instruments: three integrated tasks derived from TOEFL-iBT preparation materials, the state anxiety inventory created…
NASA Astrophysics Data System (ADS)
Marshall, J. S.
2016-12-01
We analytically construct solutions for the mean first-passage time and splitting probabilities for the escape problem of a particle moving with continuous Brownian motion in a confining planar disc with an arbitrary distribution (i.e., of any number, size and spacing) of exit holes/absorbing sections along its boundary. The governing equations for these quantities are Poisson's equation with a (non-zero) constant forcing term and Laplace's equation, respectively, and both are subject to a mixture of homogeneous Neumann and Dirichlet boundary conditions. Our solutions are expressed as explicit closed formulae written in terms of a parameterising variable via a conformal map, using special transcendental functions that are defined in terms of an associated Schottky group. They are derived by exploiting recent results for a related problem of fluid mechanics that describes a unidirectional flow over "no-slip/no-shear" surfaces, as well as results from potential theory, all of which were themselves derived using the same theory of Schottky groups. They are exact up to the determination of a finite set of mapping parameters, which is performed numerically. Their evaluation also requires the numerical inversion of the parameterising conformal map. Computations for a series of illustrative examples are also presented.
NASA Astrophysics Data System (ADS)
Faudzi, Syakinah; Abdul-Rahman, Syariza; Rahman, Rosshairy Abd; Hew, Jafri Hj. Zulkepli
2016-10-01
This paper discusses on identifying and prioritizing the student's preference criteria towards supervisor using Analytical Hierarchical Process (AHP) for student-lecturer allocation problem of internship programme. Typically a wide number of students undertake internship every semester and many preferences criteria may involve when assigning students to lecturer for supervision. Thus, identifying and prioritizing the preference criteria of assigning students to lecturer is critically needed especially when involving many preferences. AHP technique is used to prioritize the seven criteria which are capacity, specialization, academic position, availability, professional support, relationship and gender. Student's preference alternative is classified based on lecturer's academic position which are lecturer, senior lecturer, associate professor and professor. Criteria are ranked to find the best preference criteria and alternatives of the supervisor that students prefer to have. This problem is solved using Expert Choice 11 software. A sample of 30 respondents who are from semester 6 and above are randomly selected to participate in the study. By using questionnaire as our medium in collecting the student's data, consistency index is produced to validate the proposed study. Findings and result showed that, the most important preference criteria is professional support. It is followed by specialization, availability, relationship, gender, academic position and capacity. This study found that student would like to have a supportive supervisor because lack of supervision can lead the students to achieve low grade and knowledge from the internship session.
Jiang, Liuwei; Marcus, R Kenneth
2016-02-01
Capillary-channeled polymer (C-CP) fiber stationary phases are finding utility in the realms of protein analytics as well as downstream processing. We have recently described the modification of poly(ethylene terephthalate) (PET) C-CP fibers to affect amine-rich phases for the weak anion-exchange (WAX) separation of proteins. Polyethylenimine (PEI) is covalently coupled to the PET surface, with subsequent cross-linking imparted by treatment with 1,4-butanediol diglycidyl ether (BUDGE). These modifications yield vastly improved dynamic binding capacities over the unmodified fibers. We have also previously employed native (unmodified) nylon 6 C-CP fibers as weak anion/cation-exchange (mixed-mode) and hydrophobic interaction chromatography (HIC) phases for protein separations. Polyamide, nylon 6, consists of amide groups along the polymer backbone, with primary amines and carboxylic acid end groups. The analytical separation characteristics of these three amine-based C-CP fiber phases are compared here. Each of the C-CP fiber columns in this study was shown to be able to separate a bovine serum albumin/hemoglobin/lysozyme mixture at high mobile phase linear velocity (∼70 mm s(-1)) but with different elution characteristics. These differences reflect the types of protein-surface interactions that are occurring, based on the active group composition of the fiber surfaces. This study provides important fundamental understanding for the development of surface-modified C-CP fiber columns for protein separation.
NASA Astrophysics Data System (ADS)
Wu, Wen-hua; Lv, Bai-cheng; Yue, Qian-jin; Zhang, Yan-tao; Lin, Yang
2017-04-01
By focusing on the vulnerability of the structure of marine equipments, together with considering the randomness of meta-ocean load in statistics, a kind of analytical method of fatigue characteristics of marine structure based on full-scale and actual measurement of prototype is proposed. On the basis of short-term field measurement results of structural response, research is carried out on the fatigue analysis of hinge joints at the upper part of the Soft Yoke single point Mooring System (SYMS) by simultaneously monitoring the environmental load and considering the design criteria of offshore structure. Through analysis of finite element modeling, the time-histories of typical stress response are obtained, and then the assessment of fatigue damage at key hinge joints is conducted. The simulation results indicate that the proposed method can accurately analyze the fatigue damage of offshore engineering structure caused by the effect of wave load. The present analytical method of fatigue characteristics can be extended on other offshore engineering structures subjected to meta-ocean load.
Barry, Declan T; Steinberg, Marvin A; Wu, Ran; Potenza, Marc N
2009-02-01
The characteristics of Asian American and white problem gamblers using a gambling helpline were examined to identify race-related differences. Logistic regression analyses were conducted on data obtained from callers to a gambling helpline serving southern New England in 2000-2003, inclusive. Of the 144 phone calls used in the analyses, 72 were from Asian American callers and 72 were from white callers who were matched on gender, education, income, marital/cohabitation status, and age. Race-related differences were observed in forms of gambling problems, psychiatric problems secondary to gambling, substance use problems, and family history. Asian American gamblers were more likely to report suicide attempts related to gambling and problems with non-strategic gambling. White gamblers were more likely to report both casino and non-casino gambling problems and personal and familial alcohol use problems. High proportions of both groups reported problems with strategic gambling, gambling-related anxiety, family and financial problems secondary to gambling, financial debt, daily tobacco use, and a family history of problem gambling. Race-related differences should be considered in optimizing prevention and treatment strategies related to problem gambling.
Faraji, Obeidollah; Ramazani, Abbas Ali; Hedaiati, Pouria; Aliabadi, Ali; Elhamirad, Samira; Valiee, Sina
2015-11-01
Many factors influence the organizational commitment of employees. One of these factors is job designing since it affects the attitude, beliefs, and feelings of the organization employees. We aimed to determine the relationship between job characteristics and organizational commitment among the employees of hospitals. In this descriptive and correlational study, 152 Iranian employees of the hospitals (physicians, nurses, and administrative staff) were selected through stratified random sampling. Data gathered using 3-part questionnaire of "demographic information", "job characteristics model," and "organizational commitment," in 2011. Study data were analyzed using SPSS v. 16. There was significant statistical correlation between organizational commitment and variables of educational level (P = 0.001) and job category (P = 0.001). Also, a direct and significant correlation existed between motivating potential score and job feedback on one hand and organizational commitment on the other hand (P = 0.014). According to the results, managers of the hospitals should increase staff's commitment through paying attention to proper job designing.
NASA Astrophysics Data System (ADS)
Wailliez, Sébastien E.
2014-03-01
In the two-body model, time of flight between two positions can be expressed as a single-variable function and a variety of formulations exist. Lambert’s problem can be solved by inverting such a function. In this article, a method which inverts Lagrange’s flight time equation and supports the problematic 180° transfer is proposed. This method relies on a Householder algorithm of variable order. However, unlike other iterative methods, it is semi-analytical in the sense that flight time functions are derived analytically to second order vs. first order finite differences. The author investigated the profile of Lagrange’s elliptic flight time equation and its derivatives with a special focus on their significance to the behaviour of the proposed method and the stated goal of guaranteed convergence. Possible numerical deficiencies were identified and dealt with. As a test, 28 scenarios of variable difficulty were designed to cover a wide variety of geometries. The context of this research being the orbit determination of artificial satellites and debris, the scenarios are representative of typical such objects in Low-Earth, Geostationary and Geostationary Transfer Orbits. An analysis of the computational impact of the quality of the initial guess vs. that of the order of the method was also done, providing clues for further research and optimisations (e.g. asteroids, long period comets, multi-revolution cases). The results indicate fast to very fast convergence in all test cases, they validate the numerical safeguards and also give a quantitative assessment of the importance of the initial guess.
Analytical investigation in bending characteristic of twisted stacked-tape cable conductor
NASA Astrophysics Data System (ADS)
Takayasu, Makoto; Chiesa, Luisa
2015-12-01
An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour.
Experimental and analytical transonic flutter characteristics of a geared-elevator configuration
NASA Technical Reports Server (NTRS)
Ruhlin, C. L.; Doggett, R. V., Jr.; Gregory, R. A.
1980-01-01
The flutter model represented the aft fuselage and empennage of a proposed supersonic transport airplane and had an all movable horizontal tail with a geared elevator. It was tested mounted from a sting in the transonic dynamics tunnel. Symmetric flutter boundaries were determined experimentally at Mach numbers from 0.7 to 1.14 for a geared elevator configuration (gear ratio of 2.8 to 1.0) and an ungeared elevator configuration (gear ratio of 1.0 to 1.0). Gearing the elevator increased the experimental flutter dynamic pressures about 20 percent. Flutter calculations were made for the geared elevator configuration by using two analytical methods based on subsonic lifting surface theory. Both methods analyzed the stabilizer and elevator as a single, deforming surface, but one method also allowed the elevator to be analyzed as hinged from the stabilizer. All analyses predicted lower flutter dynamic pressures than experiment with best agreement (within 12 percent) for the hinged elevator method. Considering the model as mounted from a flexible rather than rigid sting in the analyses, had only a slight effect on the flutter results but was significant in that a sting related vibration mode was identified as a potentially flutter critical mode.
NASA Astrophysics Data System (ADS)
Zlotnik, V. A.; Ledder, G.; Kacimov, A. R.
2014-12-01
Disposal of excessive runoff or treated sewage into wadis and ephemeral streams is a common practice and an important hydrological problem in many Middle Eastern countries. While chemical and biological properties of the injected treated wastewater may be different from those of the receiving aquifer, the density contrast between the two fluids can be small. Therefore, studies of the fluid interface for variable density fluids or water intrusion are not directly relevant in many Managed Aquifer Recharge (MAR) problems. Other factors, such as the transient nature of injection and lack of detailed aquifer information must be considered. The disposed water reaching the water table through the vadose zone creates groundwater mounds, deforms the original water table, and develops finite-size convex-concave lenses of treated water over receiving water. After cessation of infiltration, these mounds flatten, water levels become horizontal, and infiltrated water becomes fully embedded in the receiving aquifer. The shape of the treated water body is controlled by the aquifer parameters, the magnitude of ambient flow, and the duration, rate, and cyclicity of infiltration. In case of limited aquifer data, advective transport modeling offers the most appropriate tools for predicting plume shapes over time, but surprisingly little work has been done on this important 3D flow problem. We investigate the lateral and vertical spreading of infiltrated water combining techniques of spatial velocity analyses by Zlotnik and Ledder (1992, 1993) with particle tracking. This approach allows for evaluating the geometry of the plume and the protection zone, the flow development phases, and other temporal and spatial effects and results can be used in conditions of limited data availability and quality. (Funding was provided by the USAID, DAI Subcontract 1001624-12S-19745)
Pinsky, Benjamin A; Sahoo, Malaya K; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; Denison, Blake; Higuchi, Russell; Van Atta, Reuel; Beer, Neil Reginald; Carrillo, Alda Celena; Naraghi-Arani, Pejman; Mire, Chad E; Ranadheera, Charlene; Grolla, Allen; Lagerqvist, Nina; Persing, David H
2015-01-01
The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. This study evaluated the assay's analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51-97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163-302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In summary, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.
Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; Denison, Blake; Higuchi, Russell; Van Atta, Reuel; Beer, Neil Reginald; Carrillo, Alda Celena; Naraghi-Arani, Pejman; Mire, Chad E.; Ranadheera, Charlene; Grolla, Allen; Lagerqvist, Nina; Persing, David H.
2015-11-12
The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Our study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In conclusion, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.
Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; ...
2015-11-12
The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Our study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay,more » the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In conclusion, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.« less
Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; Denison, Blake; Higuchi, Russell; Van Atta, Reuel; Beer, Neil Reginald; Carrillo, Alda Celena; Naraghi-Arani, Pejman; Mire, Chad E.; Ranadheera, Charlene; Grolla, Allen; Lagerqvist, Nina; Persing, David H.
2015-01-01
Background The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Methods and Findings This study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. Conclusion In summary, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection
Analytic characteristics of three Bayer contour blood glucose monitoring systems in neonates.
Dietzen, Dennis J; Nenninger, Denise A; Simmons, David A; Pardo, Scott; Pandya, Mauli; Fullam, Jeanellen
2015-03-01
Hypoglycemia in infants is common, is difficult to recognize, and may lead to permanent neurologic impairment. Low glucose concentrations and high hematocrits in newborns pose significant analytic challenges for whole blood glucose meters. Three Bayer glucose monitoring systems were evaluated using 211 blood samples from 162 neonates (age range 5 hours to 29 days, median age 3 days). Hematocrit and whole blood glucose were determined in heparinized whole blood, and plasma glucose was determined using the Roche Cobas 6000. Accuracy was evaluated against plasma concentrations using ISO 15197:2013 and CLSI POCT 12-A3 criteria. Glucose imprecision on the Cobas system was 1.8-2.6% (CV) from 26-610 mg/dL. Imprecision across all meter systems was 2.8% (CV) at 130 mg/dL. Glucose concentrations, hematocrit, and total bilirubin ranged from 20-150 mg/dL, 18 -75%, and 0.5-19.6 mg/dL, respectively. Linear regression analysis of whole blood versus plasma for the 3 combined systems yielded an average slope of 1.06 and correlation coefficient greater than 0.980. Bias between the Contour and Cobas was not significantly correlated with hematocrit. Greater than 99% of meter results were within 15 mg/dL and 20% of plasma results at glucose concentrations ≤ 75 and > 75 mg/dL, respectively. Of meter results, 97% were within 12.5 mg/dL of plasma results at concentrations ≤ 100 mg/dL, while 96% of meter results were within 12.5% of plasma at concentrations > 100 mg/dL. The Bayer CONTOUR Blood Glucose Monitoring Systems exceed ISO 15197:2013 and CLSI criteria in neonatal blood samples.
Dray, Julia; Bowman, Jenny; Freund, Megan; Campbell, Elizabeth; Hodder, Rebecca K; Lecathelinais, Christophe; Wiggers, John
2016-01-01
Population level data regarding the general mental health status, and the socio-demographic factors associated with the mental health status of adolescents in Australia aged 12-16 years is limited. This study assessed prevalence of mental health problems in a regional population of Australian students in Grades 7-10, and investigated associations between mental health problems and socio-demographic factors. A web-based survey was conducted in 21 secondary schools located in disadvantaged local government areas in one regional local health district of NSW Australia. Mental health problems were measured using the youth self-report Strengths and Difficulties Questionnaire (SDQ) total SDQ score and three subscale scores (internalising problems, externalising problems and prosocial behaviour). Associations between each SDQ outcome and student socio-demographic characteristics (age, gender, Aboriginal and/or Torres Strait Islander Status, remoteness of residential location and socio-economic disadvantage) were investigated. Data are reported for 6793 students aged 12-16 years. Nineteen percent of participants scored in the 'very high' range for the total SDQ, 18.0 % for internalising problems, 11.3 % for externalising problems and 8.9 % for prosocial behaviour problems. Gender and Aboriginal status were associated with all four SDQ outcomes, while age was associated with two, excluding externalising problems and prosocial behaviour. Aboriginal adolescents scored higher for mental health problems than non-Aboriginal adolescents for all four SDQ outcomes. Females scored higher than males for total SDQ and internalising problems, with mean difference greatest at age 15. Males scored higher for externalising problems and lower for prosocial behaviour than females. The finding that mental health problems significantly varied by age, gender and Aboriginality may suggest a need for tailored interventions for groups of adolescents with highest levels of mental health
Faraji, Obeidollah; Ramazani, Abbas Ali; Hedaiati, Pouria; Aliabadi, Ali; Elhamirad, Samira; Valiee, Sina
2015-01-01
Background: Many factors influence the organizational commitment of employees. One of these factors is job designing since it affects the attitude, beliefs, and feelings of the organization employees. Objectives: We aimed to determine the relationship between job characteristics and organizational commitment among the employees of hospitals. Patients and Methods: In this descriptive and correlational study, 152 Iranian employees of the hospitals (physicians, nurses, and administrative staff) were selected through stratified random sampling. Data gathered using 3-part questionnaire of “demographic information”, “job characteristics model,” and “organizational commitment,” in 2011. Study data were analyzed using SPSS v. 16. Results: There was significant statistical correlation between organizational commitment and variables of educational level (P = 0.001) and job category (P = 0.001). Also, a direct and significant correlation existed between motivating potential score and job feedback on one hand and organizational commitment on the other hand (P = 0.014). Conclusions: According to the results, managers of the hospitals should increase staff’s commitment through paying attention to proper job designing. PMID:26734472
Lee, Erica H; Zhou, Qing; Ly, Jennifer; Main, Alexandra; Tao, Annie; Chen, Stephen H
2014-04-01
Using data from a socioeconomically diverse sample of Chinese American children (n = 258, aged 6-9 years) in immigrant families, we examined the concurrent relations among neighborhood economic disadvantage and concentration of Asian residents, parenting styles, and Chinese American children's externalizing and internalizing problems. Neighborhood characteristics were measured with 2000 U.S. Census tract-level data, parents (mostly mothers) rated their own parenting styles, and parents and teachers rated children's behavioral problems. Path analysis was conducted to test two hypotheses: (a) parenting styles mediate the relations between neighborhood characteristics and children's behavioral problems, and (b) children's behavioral problems mediate the relations between neighborhood and parenting styles. We found that neighborhood Asian concentration was positively associated with authoritarian parenting, which in turn was associated with Chinese American children's higher externalizing and internalizing problems (by parents' reports). In addition, neighborhood economic disadvantage was positively related to children's externalizing problems (by parents' reports), which in turn predicted lower authoritative parenting. The current results suggest the need to consider multiple pathways in the relations among neighborhood, family, and child adjustment, and they have implications for the prevention and intervention of behavioral problems in Chinese American children.
NASA Technical Reports Server (NTRS)
Simpson, Myles A.; Mathur, Gopal P.
1992-01-01
Measurements conducted on a DC-9 aircraft test section to define the shell and cavity modes of the fuselage, understand its structural-acoustic coupling characteristics, and measure its response to different types of acoustic and vibration excitations are reported. The data were processed to generate spatial plots and wavenumber maps of the shell acceleration and cabin acoustic pressure field. Analysis and interpretation of the spatial plots and wavenumber maps showed that the only structural-acoustic coupling occurred at 105 Hz between the N=2 circumferential structural mode and the (n=2, p=0) circumferential cavity mode. The fuselage response to vibration excitation was found to be dominated by modes whose order increases with frequency.
NASA Technical Reports Server (NTRS)
Simpson, Myles A.; Mathur, Gopal P.
1992-01-01
Measurements conducted on a DC-9 aircraft test section to define the shell and cavity modes of the fuselage, understand its structural-acoustic coupling characteristics, and measure its response to different types of acoustic and vibration excitations are reported. The data were processed to generate spatial plots and wavenumber maps of the shell acceleration and cabin acoustic pressure field. Analysis and interpretation of the spatial plots and wavenumber maps showed that the only structural-acoustic coupling occurred at 105 Hz between the N=2 circumferential structural mode and the (n=2, p=0) circumferential cavity mode. The fuselage response to vibration excitation was found to be dominated by modes whose order increases with frequency.
NASA Astrophysics Data System (ADS)
Chew, W. C.; Kong, J. A.
1981-09-01
Through the matched asymptotic expansions technique, asymptotic eigenequations for the even and odd modes of an open wide microstrip transmission line are derived. The eigenequations, and simplifications thereof which do not involve integration, can be solved easily for the effective permittivity. Even though d/W is assumed to be small, the solutions are good even if d/W is approximately 0.8 when compared with the numerical results of Jansen (1978). From these eigenequations, asymptotic formulas for the effective permittivity can be derived which are excellent when d/W is approximately 0.2. When the frequency goes to zero, the asymptotic formula derived under the quasi-TEM approximation in Mittra and Itoh (1970) were reproduced. The asymptotic analysis provides good physical insight into the problem, otherwise unavailable from numerical analysis.
Human-machine analytics for closed-loop sense-making in time-dominant cyber defense problems
NASA Astrophysics Data System (ADS)
Henry, Matthew H.
2017-05-01
Many defense problems are time-dominant: attacks progress at speeds that outpace human-centric systems designed for monitoring and response. Despite this shortcoming, these well-honed and ostensibly reliable systems pervade most domains, including cyberspace. The argument that often prevails when considering the automation of defense is that while technological systems are suitable for simple, well-defined tasks, only humans possess sufficiently nuanced understanding of problems to act appropriately under complicated circumstances. While this perspective is founded in verifiable truths, it does not account for a middle ground in which human-managed technological capabilities extend well into the territory of complex reasoning, thereby automating more nuanced sense-making and dramatically increasing the speed at which it can be applied. Snort1 and platforms like it enable humans to build, refine, and deploy sense-making tools for network defense. Shortcomings of these platforms include a reliance on rule-based logic, which confounds analyst knowledge of how bad actors behave with the means by which bad behaviors can be detected, and a lack of feedback-informed automation of sensor deployment. We propose an approach in which human-specified computational models hypothesize bad behaviors independent of indicators and then allocate sensors to estimate and forecast the state of an intrusion. State estimates and forecasts inform the proactive deployment of additional sensors and detection logic, thereby closing the sense-making loop. All the while, humans are on the loop, rather than in it, permitting nuanced management of fast-acting automated measurement, detection, and inference engines. This paper motivates and conceptualizes analytics to facilitate this human-machine partnership.
The Characteristic of the Process of Students' Metacognition in Solving Calculus Problems
ERIC Educational Resources Information Center
Purnomo, Dwi; Nusantara, Toto; Subanji; Rahardjo, Swasono
2017-01-01
This article is the result of research aims to describe the patterns and characteristics of the process of metacognition student of mathematics in solving calculus problems. Description was done by looking at changes in "awareness," "evaluation," and "regulation" as components of metacognition. The changes in…
Integral Method of Boundary Characteristics in Solving the Stefan Problem: Dirichlet Condition
NASA Astrophysics Data System (ADS)
Kot, V. A.
2016-09-01
The integral method of boundary characteristics is considered as applied to the solution of the Stefan problem with a Dirichlet condition. On the basis of the multiple integration of the heat-conduction equation, a sequence of identical equalities with boundary characteristics in the form of n-fold integrals of the surface temperature has been obtained. It is shown that, in the case where the temperature profile is defined by an exponential polynomial and the Stefan condition is not fulfilled at a moving interphase boundary, the accuracy of solving the Stefan problem with a Dirichlet condition by the integral method of boundary characteristics is higher by several orders of magnitude than the accuracy of solving this problem by other known approximate methods and that the solutions of the indicated problem with the use of the fourth-sixth degree polynomials on the basis of the integral method of boundary characteristics are exact in essence. This method surpasses the known numerical methods by many orders of magnitude in the accuracy of calculating the position of the interphase boundary and is approximately equal to them in the accuracy of calculating the temperature profile.
Investigating Grade Nine Textbook Problems for Characteristics Related to Mathematical Literacy
ERIC Educational Resources Information Center
Gatabi, Abolfazl Rafiepour; Stacey, Kaye; Gooya, Zahra
2012-01-01
This study presents a content analysis of the new Iranian Grade 9 mathematics textbook and two Australian Year 9 mathematics textbooks, examining the extent to which the problems show characteristics associated in the literature with promoting mathematical literacy. The new Iranian book was produced to meet a range of needs including several well…
ERIC Educational Resources Information Center
Johnson, Cynthia R.; Turner, Kylan; Stewart, Patricia A.; Schmidt, Brianne; Shui, Amy; Macklin, Eric; Reynolds, Anne; James, Jill; Johnson, Susan L.; Manning Courtney, Patty; Hyman, Susan L.
2014-01-01
Many children with autism spectrum disorders (ASD) have co-occurring feeding problems. However, there is limited knowledge about how these feeding habits are related to other behavioral characteristics ubiquitous in ASD. In a relatively large sample of 256 children with ASD, ages 2-11, we examined the relationships between feeding and mealtime…
Small/Rural Two-Year Colleges: An Analysis of Their Problems and Characteristics.
ERIC Educational Resources Information Center
Ross, Robert Allison
A nationwide survey of two-year colleges was conducted in 1978 to determine the unique characteristics of the country's small and/or rural colleges. The survey instrument asked college presidents to indicate if their institutions could be considered small and/or rural and to rank the importance of 32 selected problem areas. Survey findings, based…
ERIC Educational Resources Information Center
Houtz, John C.; Shaning, Dennis J.
1982-01-01
Predicted divergent thinking and problem-solving performance of elementary school students from teachers' ratings of students' affective/behavioral characteristics, and from intelligence test scores. Found teachers' ratings of sensitivity to beauty, risk taking, awareness of impulses, and humor were the most frequent significant predictors in…
ERIC Educational Resources Information Center
Johnson, Cynthia R.; Turner, Kylan; Stewart, Patricia A.; Schmidt, Brianne; Shui, Amy; Macklin, Eric; Reynolds, Anne; James, Jill; Johnson, Susan L.; Manning Courtney, Patty; Hyman, Susan L.
2014-01-01
Many children with autism spectrum disorders (ASD) have co-occurring feeding problems. However, there is limited knowledge about how these feeding habits are related to other behavioral characteristics ubiquitous in ASD. In a relatively large sample of 256 children with ASD, ages 2-11, we examined the relationships between feeding and mealtime…
The role of paternal drinking problems in the psychological characteristics of high school students.
Choi, Dong Hyun; Kim, Jong Sung; Jung, Jin Gyu; Ryou, Young Il; Kim, Young Seok; Uh, Won Chul
2013-11-01
It has been reported that children with parental drinking problems are at increased risk of drinking problems or psychiatric diseases in adulthood. The present study was conducted to examine the psychiatric characteristics of high school students according to paternal drinking problems. The subjects were 950 high school students (390 male and 560 female). The paternal drinking problems were assessed by using the Father-Short Michigan Alcoholism Screening Test. The Alcohol Use Disorders Identification Test, Beck's depression inventory, and Beck's anxiety inventory were used to evaluate the drinking behavior, depression, and anxiety of high school students. While male students with paternal drinking problems showed significantly increased risk of anxiety (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.05 to 4.63), female students with paternal drinking problems showed significantly increased risk of depression (OR, 1.84; 95% CI, 1.24 to 2.74) according to the results of logistic regression analysis with adjustments for participants' age, whether they live together with parents, their religion, club activities, and smoking habits on the basis of students without paternal drinking problems. The above results suggest that paternal drinking problems lead to unstable mentalities in both male and female students, and that a family physician should address the mental state of teenagers with paternal drinking problems during clinical encounters.
Walach, Harald; Loef, Martin
2015-11-01
The hierarchy of evidence presupposes linearity and additivity of effects, as well as commutativity of knowledge structures. It thereby implicitly assumes a classical theoretical model. This is an argumentative article that uses theoretical analysis based on pertinent literature and known facts to examine the standard view of methodology. We show that the assumptions of the hierarchical model are wrong. The knowledge structures gained by various types of studies are not sequentially indifferent, that is, do not commute. External validity and internal validity are at least partially incompatible concepts. Therefore, one needs a different theoretical structure, typical of quantum-type theories, to model this situation. The consequence of this situation is that the implicit assumptions of the hierarchical model are wrong, if generalized to the concept of evidence in total. The problem can be solved by using a matrix-analytical approach to synthesizing evidence. Here, research methods that produce different types of evidence that complement each other are synthesized to yield the full knowledge. We show by an example how this might work. We conclude that the hierarchical model should be complemented by a broader reasoning in methodology. Copyright © 2015 Elsevier Inc. All rights reserved.
Chen, Chong; Wu, Fan; Geng, Hongwei; Shen, Wei; Wang, Mingtai
2011-04-19
The photocurrent in bilayer polymer photovoltaic cells is dominated by the exciton dissociation efficiency at donor/acceptor interface. An analytical model is developed for the photocurrent-voltage characteristics of the bilayer polymer/TiO2 photovoltaic cells. The model gives an analytical expression for the exciton dissociation efficiency at the interface, and explains the dependence of the photocurrent of the devices on the internal electric field, the polymer and TiO2 layer thicknesses. Bilayer polymer/TiO2 cells consisting of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and TiO2, with different thicknesses of the polymer and TiO2 films, were prepared for experimental purposes. The experimental results for the prepared bilayer MEH-PPV/TiO2 cells under different conditions are satisfactorily fitted to the model. Results show that increasing TiO2 or the polymer layer in thickness will reduce the exciton dissociation efficiency in the device and further the photocurrent. It is found that the photocurrent is determined by the competition between the exciton dissociation and charge recombination at the donor/acceptor interface, and the increase in photocurrent under a higher incident light intensity is due to the increased exciton density rather than the increase in the exciton dissociation efficiency.
NASA Astrophysics Data System (ADS)
Jaikumar, M. G.; Rao, R. Ramakrishna; Karmalkar, Shreepad
2015-12-01
The high concentration of interface traps in SiC Double-implanted (D) MOSFETs makes the threshold voltage imprecise, and kills the surface mobility which raises the channel and accumulation layer resistances. Using a detailed comparison with numerical simulations, we examine the extent to which the above factors make analytical on-resistance models, which have proved useful for designing Si DMOSFETs, inaccurate for SiC DMOSFET design. Practical devices are 3-D; however, 3-D simulation is time and resource intensive, and prone to convergence problems. We discuss prediction of 3-D simulations of a square cell SiC DMOSFET having interface traps, field dependent mobility and non-uniform doping, using either 2-D simulation of a linear cell device and "inaccurate" analytical models, or 2-D simulation using rotational symmetry. Finally, we report a procedure for calibration of the mobility and interface trap parameters useful for simulating the on-state DC behavior of 4H-SiC DMOSFETs including the effect of elevated temperatures.
NASA Astrophysics Data System (ADS)
Wang, Weiguang; Zou, Shan; Shao, Quanxi; Xing, Wanqiu; Chen, Xi; Jiao, Xiyun; Luo, Yufeng; Yong, Bin; Yu, Zhongbo
2016-10-01
The concept of elasticity has been widely employed to quantify the hydrological response to changes in climate and catchments properties. To separate the effect of different climatic variables on runoff, the potential evaporation (E0) elasticity of runoff needs to be presented in term of observed climate variables. To fully reflect the effects of maximum and minimum temperatures and reduce the influence of the correlations of radiation with sunshine duration and relative humidity on the assessment results, we decompose the E0 elasticity into five evaporation-related elasticities (i.e., sunshine duration, maximum and minimum temperature, wind speed and relative humidity) via the first-order differentiation of the FAO 56 Penman equation. As the catchment runoff is frequently affected by the land use/cover change, we also consider changes in catchment characteristics and derive a catchment alteration elasticity based on the Budyko framework. An application was carried out in 30 catchments with widespread climatic types in China. For the two periods (i.e., the baseline period and the changed period) divided by the Pettitt test, the contributions of different climatic variables and land use/cover conditions to runoff change were quantified. In general, the alteration of catchment characteristics and climatic change should be mainly responsible for changes in runoff in water-limited and humid basins, respectively. Although the elasticity of maximum temperature are usually higher than that of minimum temperature, the contributions to runoff change present the opposite direction. Furthermore, additional analysis indicated some overestimation in relative humidity elasticities in the previous studies, further emphasizing the necessity of our extension to alleviate the influence of correlation between climatic variables to the assessment results. Moreover, the results of model performance versus model complexity showed that the choice of model complexity still depends on the
Malaterre, Vincent; Pedersen, Maireadh; Ogorka, Joerg; Gurny, Robert; Loggia, Nicoletta; Taday, Philip F
2010-01-01
The aim of this study was to investigate coating characteristics of push-pull osmotic systems (PPOS) using three-dimensional terahertz pulsed imaging (3D-TPI) and to detect physical alterations potentially impacting the drug release. The terahertz time-domain reflection signal was used to obtain information on both the spatial distribution of the coating thickness and the coating internal physical mapping. The results showed that (i) the thickness distribution of PPOS coating can be non-destructively analysed using 3D-TPI and (ii) internal physical alterations impacting the drug release kinetics were detectable by using the terahertz time-domain signal. Based on the results, the potential benefits of implementing 3D-TPI as quality control analytical tool were discussed.
Shevyrin, Vadim; Melkozerov, Vladimir; Nevero, Alexander; Eltsov, Oleg; Shafran, Yuri; Morzherin, Yuri; Lebedev, Albert T
2015-08-01
Illicit new psychoactive substances (NPS) are a serious threat to health throughout the world. Such NPS do not usually pass preliminary pharmacological trials. In 2014, we identified a series of five new synthetic cannabinoids with an indazole-3-carboxamide structure bearing an N-1-methoxycarbonylalkyl group. The compounds have very high cannabimimetic activity which has caused mass severe intoxication and deaths. The compounds were identified by means of gas chromatography-mass spectrometry (GC-MS), including high-resolution mass spectrometry (GC-HRMS), ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS(2)), and (1)H and (13)C nuclear magnetic resonance spectroscopy (NMR). The peculiarities of mass-spectral fragmentation of the compounds after electron ionization (EI) ionization and collision-induced dissociation (CID) were studied. The analytical characteristics reported for the compounds will enable their identification in a variety of materials seized from criminals.Graphical Abstract.
2014-01-01
A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors. PMID:24636423
Przyjazny, Andrzej; Kokosa, John M
2002-11-22
Headspace solvent microextraction (HSM) is a novel method of sample preparation for chromatographic analysis. It involves exposing a microdrop of high-boiling point organic solvent extruded from the needle tip of a gas chromatographic syringe to the headspace above a sample. Volatile organic compounds are extracted and concentrated in the microdrop. Next, the microdrop is retracted into the microsyringe and injected directly into the chromatograph. HSM has a number of advantages, including renewable drop (no sample carryover), low cost, simplicity and ease of use, short time of analysis, high sensitivity and low detection limits, good precision, minimal solvent use, and no need for instrument modification. This paper presents analytical characteristics of HSM as applied to the determination of benzene, toluene, ethylbenzene and xylenes in water.
NASA Astrophysics Data System (ADS)
Shelyakina, Margaryta K.; Soldatkin, Oleksandr O.; Arkhypova, Valentyna M.; Kasap, Berna O.; Akata, Burcu; Dzyadevych, Sergei V.
2014-03-01
A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors.
NASA Technical Reports Server (NTRS)
Damerow, W. P.; Murtaugh, J. P.; Burggraf, F.
1972-01-01
The flow characteristics of turbine airfoil cooling system components were experimentally investigated. Flow models representative of leading edge impingement, impingement with crossflow (midchord cooling), pin fins, feeder supply tube, and a composite model of a complete airfoil flow system were tested. Test conditions were set by varying pressure level to cover the Mach number and Reynolds number range of interest in advanced turbine applications. Selected geometrical variations were studied on each component model to determine these effects. Results of these tests were correlated and compared with data available in the literature. Orifice flow was correlated in terms of discharge coefficients. For the leading edge model this was found to be a weak function of hole Mach number and orifice-to-impinged wall spacing. In the impingement with crossflow tests, the discharge coefficient was found to be constant and thus independent of orifice Mach number, Reynolds number, crossflow rate, and impingement geometry. Crossflow channel pressure drop showed reasonable agreement with a simple one-dimensional momentum balance. Feeder tube orifice discharge coefficients correlated as a function of orifice Mach number and the ratio of the orifice-to-approach velocity heads. Pin fin data was correlated in terms of equivalent friction factor, which was found to be a function of Reynolds number and pin spacing but independent of pin height in the range tested.
NASA Astrophysics Data System (ADS)
Wei, Xiaoling; Du, Liangwei; Li, Dongmei; Gong, Qi; Wang, Lisheng; Lin, Yu
In this paper, Ni (II) reacting with captopril (CPT) can form complex in alkaline solution and the formed complex has a characteristic absorption peak at 340 nm. The absorbance of the Ni-CPT complex increases linearly with the increased concentration of captopril. The study also shows that ammonia has an obvious sensitizing effect on the absorbance. Based on the study, a new method for the determination of captopril is established. Experimental results show that the linear range of this method under optimum condition is 1.0-60 mg/L with correlation coefficient, detection limit and precision of 0.9999, 0.31 mg/L and 0.87%, respectively. The method used to determine captopril in commercial captopril tablets has a satisfactory result with the recoveries in the range of 99.0-103.6% and the relative standard deviation (RSD) in the range of 0.8-3.7%. We preliminarily study the reaction mechanism and demonstrate that the complex ratio of Ni (II) with captopril is 1:2 and the formation constant is 6.3 × 109.
Wei, Xiaoling; Du, Liangwei; Li, Dongmei; Gong, Qi; Wang, Lisheng; Lin, Yu
2012-08-01
In this paper, Ni (II) reacting with captopril (CPT) can form complex in alkaline solution and the formed complex has a characteristic absorption peak at 340nm. The absorbance of the Ni-CPT complex increases linearly with the increased concentration of captopril. The study also shows that ammonia has an obvious sensitizing effect on the absorbance. Based on the study, a new method for the determination of captopril is established. Experimental results show that the linear range of this method under optimum condition is 1.0-60mg/L with correlation coefficient, detection limit and precision of 0.9999, 0.31mg/L and 0.87%, respectively. The method used to determine captopril in commercial captopril tablets has a satisfactory result with the recoveries in the range of 99.0-103.6% and the relative standard deviation (RSD) in the range of 0.8-3.7%. We preliminarily study the reaction mechanism and demonstrate that the complex ratio of Ni (II) with captopril is 1:2 and the formation constant is 6.3×10(9). Copyright © 2012 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Chernyshev, Vsevolod L.; Tolchennikov, Anton A.; Shafarevich, Andrei I.
2016-09-01
We review our recent results concerning the propagation of "quasi-particles" in hybrid spaces — topological spaces obtained from graphs via replacing their vertices by Riemannian manifolds. Although the problem is purely classical, it is initiated by the quantum one, namely, by the Cauchy problem for the time-dependent Schrödinger equation with localized initial data.We describe connections between the behavior of quasi-particles with the properties of the corresponding geodesic flows. We also describe connections of our problem with various problems in analytic number theory.
Christenson, R H; Apple, F S; Morgan, D L; Alonsozana, G L; Mascotti, K; Olson, M; McCormack, R T; Wians, F H; Keffer, J H; Duh, S H
1998-01-01
We evaluated the ACCESS cardiac troponin I (cTnI) immunoassay as a marker for myocardial infarction (MI). Total imprecision was 6.0% to 13.5%, the minimum detectable concentration was 0.007 microg/L, and the limit of quantitation was 0.046 microg/L. Comparison of cTnI measurement between the ACCESS and Stratus systems (n = 114) showed a proportional difference: ACCESS cTnI = 0.0996 Stratus cTnI + 0.049 microg/L (r = 0.811). Fifty-nine of 61 ambulatory patients without cardiac symptoms had no detectable cTnI (95% range, 0.00 to 0.025 microg/L). The optimum cutoff for discriminating MI (n = 289, 45 with MI) was 0.15 microg/L by receiver operator characteristic curve analysis; at this cutoff, the ACCESS cTnI assay showed a sensitivity of 88.9% (95% CI, 79.7-98.1%) and specificity of 91.8% (95% CI, 88.4-95.2%). The ACCESS cTnI assay results showed 89.4% and 93.0% concordance with the MB isoenzyme of creatine kinase (CK-MB) mass and Stratus cTnI results, respectively, for classification of patients with suspected MI. The ACCESS cTnI assay appears to show sensitivity and specificity comparable with those of both CK-MB mass and Stratus cTnI assays for the diagnosis of MI in patients presenting within 12 h of onset of symptoms.
Hing, Nerilee; Russell, Alex M T
2017-09-01
Background and aims Few studies have examined the stigma of problem gambling and little is known about those who internalize this prejudice as damaging self-stigma. This paper aimed to identify psychological factors, sociodemographic characteristics, and coping mechanisms associated with the self-stigma of problem gambling. Methods An online survey was conducted on 177 Australian adults with a current gambling problem to measure self-stigma, self-esteem, social anxiety, self-consciousness, psychological distress, symptom severity, most problematic gambling form, stigma coping mechanisms, and sociodemographic characteristics. Results All variables significantly correlated with self-stigma were considered for inclusion in a regression model. A multivariate linear regression indicated that higher levels of self-stigma were associated with: being female, being older, lower self-esteem, higher problem gambling severity score, and greater use of secrecy (standardized coefficients: 0.16, 0.14, -0.33, 0.23, and 0.15, respectively). Strongest predictors in the model were self-esteem, followed by symptom severity score. Together, predictors in the model accounted for 38.9% of the variance in self-stigma. Discussion and conclusions These results suggest that the self-stigma of problem gambling may be driven by similar mechanisms as the self-stigma of other mental health disorders, and impact similarly on self-esteem and coping. Thus, self-stigma reduction initiatives used for other mental health conditions may be effective for problem gambling. In contrast, however, the self-stigma of problem gambling increased with female gender and older age, which are associated with gaming machine problems. This group should, therefore, be a target population for efforts to reduce or better cope with the self-stigma of problem gambling.
NASA Astrophysics Data System (ADS)
Sperling, Michael; Welz, Bernard; Hertzberg, Joachim; Rieck, Christof; Marowsky, Gerd
1996-07-01
compared with those obtained earlier for a longitudinally heated graphite tube atomizer (HGA), including some analytical applications of these two furnace types. Both the temperature characteristics and the resulting analytical characteristics substantiate the superiority of the THGA in comparison to the HGA as an atomizer for ETAAS.
2013-01-01
Background The past decade has witnessed a growing body of research on welfare state characteristics and health inequalities but the picture is, despite this, inconsistent. We aim to review this research by focusing on theoretical and methodological differences between studies that at least in part may lead to these mixed findings. Methods Three reviews and relevant bibliographies were manually explored in order to find studies for the review. Related articles were searched for in PubMed, Web of Science and Google Scholar. Database searches were done in PubMed and Web of Science. The search period was restricted to 2005-01-01 to 2013-02-28. Fifty-four studies met the inclusion criteria. Results Three main approaches to comparative welfare state research are identified; the Regime approach, the Institutional approach, and the Expenditure approach. The Regime approach is the most common and regardless of the empirical regime theory employed and the amendments made to these, results are diverse and contradictory. When stratifying studies according to other features, not much added clarity is achieved. The Institutional approach shows more consistent results; generous policies and benefits seem to be associated with health in a positive way for all people in a population, not only those who are directly affected or targeted. The Expenditure approach finds that social and health spending is associated with increased levels of health and smaller health inequalities in one way or another but the studies are few in numbers making it somewhat difficult to get coherent results. Conclusions Based on earlier reviews and our results we suggest that future research should focus less on welfare regimes and health inequalities and more on a multitude of different types of studies, including larger analyses of social spending and social rights in various policy areas and how these are linked to health in different social strata. But, we also need more detailed evaluation of
"Live Chat" Clients at Kids Help Phone: Individual Characteristics and Problem Topics.
Haner, Dilys; Pepler, Debra
2016-01-01
Young people in Canada prefer to use the Internet over face-to-face contact when seeking help for problems of daily living and mental health problems. Kids Help Phone (KHP) provides on-demand, anonymous help to young people via telephone and Live Chat technologies. Two hundred thirty-two phone clients and 230 Live Chat clients responded to a questionnaire at this otherwise anonymous service, providing previously inaccessible data about their individual characteristics and characterizations of the problems for which they sought help. There was a larger proportion of weighty problems (mental health and suicide) among chatters than callers. There were also more non-heterosexual youth, and those who identified as Asian and Black African or Caribbean, using Live Chat than phone. Implications for training Live Chat counsellors to respond effectively to chatters are discussed.
“Live Chat” Clients at Kids Help Phone: Individual Characteristics and Problem Topics
Haner, Dilys; Pepler, Debra
2016-01-01
Objective Young people in Canada prefer to use the Internet over face-to-face contact when seeking help for problems of daily living and mental health problems. Kids Help Phone (KHP) provides on-demand, anonymous help to young people via telephone and Live Chat technologies. Methods Two hundred thirty-two phone clients and 230 Live Chat clients responded to a questionnaire at this otherwise anonymous service, providing previously inaccessible data about their individual characteristics and characterizations of the problems for which they sought help. Results There was a larger proportion of weighty problems (mental health and suicide) among chatters than callers. There were also more non-heterosexual youth, and those who identified as Asian and Black African or Caribbean, using Live Chat than phone. Conclusions Implications for training Live Chat counsellors to respond effectively to chatters are discussed. PMID:27924143
Schlarb, Angelika A; Kulessa, Dominika; Gulewitsch, Marco D
2012-01-01
Background Sleep problems, especially insomnia, are a common complaint among adults. International studies on university students have shown prevalence rates between 4.7% and 36.2% for sleep difficulties, and 13.1% and 28.1% for insomnia. Sleep problems are associated with lower social and academic performance and can have a severe impact on psychological and physical health. Objective The goal of this study was to outline sleep characteristics, prevalence of sleep problems, insomnia, and associations with self-efficacy among German university students. Methods A total of 2196 university students (70.9% women; mean age 24.16 years) participated in the study. Sleep characteristics, sleep problems, insomnia, and self-efficacy were assessed using a questionnaire. Results and conclusion Analyses revealed that more than 16% of surveyed students needed more than 30 minutes to fall asleep. About 7.7% of the students suffered from insomnia. Short sleep was significantly associated with a considerably increased rate of insomnia (20%). Insomniacs showed lower self-efficacy than students without sleep problems. PMID:23616724
DEMİR, Türkay; BOLAT, Nurullah; YAVUZ, Mesut; KARAÇETİN, Gül; DOĞANGÜN, Burak; KAYAALP, Levent
2014-01-01
Introduction This study aimed to assess the behavioral problems and the attachment characteristics of children and adolescents with congenital blindness (CB). Method Forty children and adolescents aged 11–14 years with CB were included as the case group. Forty healthy children and adolescents who were matched for age, gender, and socioeconomic status with the case group served as the comparison group. Behavioral problems were assessed by the Child Behavior Checklist for ages 4–18 (CBCL 4/18). Attachment characteristics were assessed via the Short Form of Inventory of Parent and Peer Attachment (s-IPPA). Results The case group had lower CBCL total problems scores as well as anxiety/depression, withdrawal/depression, and attention problems subscales scores with respect to the comparison group. There were no significant differences between the two groups in s-IPPA scores. Conclusion Children and adolescents with CB did not differ from the comparison group in terms of attachment, whereas, they had lower scores on behavioral problems than the comparison group. Although previous studies indicate that children and adolescents with CB may be at the risk of insecure attachment, our study suggested that adaptive mechanisms of their families together with professional help from specialized teachers and services provided by schools for children and adolescents with CB may play compensatory roles. PMID:28360610
Learning and teaching in small groups: characteristics, benefits, problems and approaches.
Jones, R W
2007-08-01
Small group learning may be defined as a group of learners demonstrating three common characteristics; active participation, a specific task and reflection. This article provides an overview of small group learning and teaching, describes the characteristics of this form of small group work, benefits, problems, potential causes of less than optimal sessions, and summarises specific approaches. These include tutorials, free-discussion groups, brainstorming, snowballing, buzz groups, paired (or one-to-one) discussion, clinical teaching, simulations, seminars, plenary sessions, problem-based learning, team-based learning, role plays, games and IT approaches. The article concludes with an emphasis on the importance of the teacher and a check list for use when planning, teaching and evaluating a small group session.
NASA Astrophysics Data System (ADS)
Shin, Kyung-Hun; Park, Hyung-Il; Cho, Han-Wook; Choi, Jang-Young
2017-05-01
This paper presents the torque calculation and parametric analysis of a coaxial magnetic gear (CMG). We obtained analytical magnetic field solutions produced by permanent magnets based on a magnetic vector potential. Then, the analytical solutions for magnetic torque were obtained. All analytical results were extensively validated with nonlinear two-dimensional finite element analysis. Finally, using the derived analytical magnetic torque solutions, we carried out parametric analysis to determine the influence of the design parameters on the CMG's behavior.
Engels, Rutger C M E; Vermulst, Ad A; Dubas, Judith S; Bot, Sander M; Gerris, Jan
2005-01-01
Several studies have shown that disturbances in the parent-child relationship in childhood are related to patterns of alcohol abuse in adolescence and young adulthood. Recently some researchers, however, argue that whether poor parenting is detrimental depends on specific child characteristics. Hence, instead of examining overall effects of parenting, it might be more appropriate to search for specific child-environment effects that lead to problematic drinking patterns. In this paper, we investigate the interplay between child characteristics (lack of self-control and aggression) and parenting on problematic alcohol use in young adulthood. Data were used from a longitudinal study that followed 301 children and their parents for a period of 10 years. Both parents and their children were interviewed on parenting practices and child characteristics when the child was a young adolescent (mean age of 12 years at time 1) and extensive information on problematic alcohol use was gathered when the participants were young adults (mean age was 22 at time 3). Findings showed strong effects of childhood aggression (men only) and poor family functioning on enhanced levels of problem drinking in young adulthood. Further, the combination of high levels of aggression and low levels of family functioning were related to problem drinking in men, whereas the combination of low parental control and low levels of affection expression were related to problem drinking in women.
Quilty, Lena C; Avila Murati, Daniela; Bagby, R Michael
2014-03-01
Many gamblers would prefer to reduce gambling on their own rather than to adopt an abstinence approach within the context of a gambling treatment program. Yet responsible gambling guidelines lack quantifiable markers to guide gamblers in wagering safely. To address these issues, the current investigation implemented receiver operating characteristic (ROC) analysis to identify behavioral indicators of harmful and problem gambling. Gambling involvement was assessed in 503 participants (275 psychiatric outpatients and 228 community gamblers) with the Canadian Problem Gambling Index. Overall gambling frequency, duration, and expenditure were able to distinguish harmful and problematic gambling at a moderate level. Indicators of harmful gambling were generated for engagement in specific gambling activities: frequency of tickets and casino; duration of bingo, casino, and investments; and expenditures on bingo, casino, sports betting, games of skill, and investments. Indicators of problem gambling were similarly produced for frequency of tickets and casino, and expenditures on bingo, casino, games of skill, and investments. Logistic regression analyses revealed that overall gambling frequency uniquely predicted the presence of harmful and problem gambling. Furthermore, frequency indicators for tickets and casino uniquely predicted the presence of both harmful and problem gambling. Together, these findings contribute to the development of an empirically based method enabling the minimization of harmful or problem gambling through self-control rather than abstinence.
Oswald, Tasha M; Beck, Jonathan S; Iosif, Ana-Maria; McCauley, James B; Gilhooly, Leslie J; Matter, John C; Solomon, Marjorie
2016-04-01
Mathematics achievement in autism spectrum disorder (ASD) has been understudied. However, the ability to solve applied math problems is associated with academic achievement, everyday problem-solving abilities, and vocational outcomes. The paucity of research on math achievement in ASD may be partly explained by the widely-held belief that most individuals with ASD are mathematically gifted, despite emerging evidence to the contrary. The purpose of the study was twofold: to assess the relative proportions of youth with ASD who demonstrate giftedness versus disability on applied math problems, and to examine which cognitive (i.e., perceptual reasoning, verbal ability, working memory) and clinical (i.e., test anxiety) characteristics best predict achievement on applied math problems in ASD relative to typically developing peers. Twenty-seven high-functioning adolescents with ASD and 27 age- and Full Scale IQ-matched typically developing controls were assessed on standardized measures of math problem solving, perceptual reasoning, verbal ability, and test anxiety. Results indicated that 22% of the ASD sample evidenced a mathematics learning disability, while only 4% exhibited mathematical giftedness. The parsimonious linear regression model revealed that the strongest predictor of math problem solving was perceptual reasoning, followed by verbal ability and test anxiety, then diagnosis of ASD. These results inform our theories of math ability in ASD and highlight possible targets of intervention for students with ASD struggling with mathematics.
NASA Technical Reports Server (NTRS)
Lamar, J. E.; Frink, N. T.
1981-01-01
Sixteen analytically and empirically designed strakes have been tested experimentally on a wing-body at three subcritical speeds in such a way as to isolate the strake-forebody loads from the wing-afterbody loads. Analytical estimates for these longitudinal results are made using the suction analogy and the augmented vortex lift concepts. The synergistic data are reasonably well estimated or bracketed by the high- and low-angle-of-attack vortex lift theories over the Mach number range and up to maximum lift or strake-vortex breakdown over the wing. Also, the strake geometry is very important in the maximum lift value generated and the lift efficiency of a given additional area. Increasing size and slenderness ratios are important is generating lift efficiently, but similar efficiency can also be achieved by designing a strake with approximately half the area of the largest gothic strake tested. These results correlate well with strake-vortex-breakdown observations in the water tunnel.
Building characteristics associated with moisture related problems in 8,918 Swedish dwellings.
Hägerhed-Engman, Linda; Bornehag, Carl-Gustaf; Sundell, Jan
2009-08-01
Moisture problems in buildings have in a number of studies been shown to increase the risk for respiratory symptoms. The study Dampness in Buildings and Health (DBH) was initiated with the aim to identify health relevant exposures related to dampness in buildings. A questionnaire study about home environment with a focus on dampness problems and health was conducted in one county of Sweden (8,918 homes, response rate 79%). Building characteristics that were associated with one or more of the dampness indicators were for single-family houses, older houses, flat-roofed houses built in the 1960s and 1970s, houses with a concrete slab on the ground that were built before 1983. Moreover, tenancy and earlier renovation due to mould or moisture problems was strongly associated with dampness. A perception of dry air was associated with window-pane condensation, e.g. humid indoor air.
The linearized characteristics method and its application to practical nonlinear supersonic problems
NASA Technical Reports Server (NTRS)
Ferri, Antonio
1952-01-01
The methods of characteristics has been linearized by assuming that the flow field can be represented as a basic flow field determined by nonlinearized methods and a linearized superposed flow field that accounts for small changes of boundary conditions. The method has been applied to two-dimensional rotational flow where the basic flow is potential flow and to axially symmetric problems where conical flows have been used as the basic flows. In both cases the method allows the determination of the flow field to be simplified and the numerical work to be reduced to a few calculations. The calculations of axially symmetric flow can be simplified if tabulated values of some coefficients of the conical flow are obtained. The method has also been applied to slender bodies without symmetry and to some three-dimensional wing problems where two-dimensional flow can be used as the basic flow. Both problems were unsolved before in the approximation of nonlinear flow.
Identification of dynamic characteristics of flexible rotors as dynamic inverse problem
NASA Technical Reports Server (NTRS)
Roisman, W. P.; Vajingortin, L. D.
1991-01-01
The problem of dynamic and balancing of flexible rotors were considered, which were set and solved as the problem of the identification of flexible rotor systems, which is the same as the inverse problem of the oscillation theory dealing with the task of the identifying the outside influences and system parameters on the basis of the known laws of motion. This approach to the problem allows the disclosure the picture of disbalances throughout the rotor-under-test (which traditional methods of flexible rotor balancing, based on natural oscillations, could not provide), and identify dynamic characteristics of the system, which correspond to a selected mathematical model. Eventually, various methods of balancing were developed depending on the special features of the machines as to their design, technology, and operation specifications. Also, theoretical and practical methods are given for the flexible rotor balancing at far from critical rotation frequencies, which does not necessarily require the knowledge forms of oscillation, dissipation, and elasticity and inertia characteristics, and to use testing masses.
Sleep Characteristics, Sleep Problems, and Associations to Quality of Life among Psychotherapists.
Schlarb, Angelika A; Reis, Dorota; Schröder, Annette
2012-01-01
Sleep problems, especially insomnia, are a common complaint among adults. International studies have shown prevalence rates between 4.7 and 36.2% for sleep difficulties in general, whereas 13.1-28.1% report insomnia symptoms. Sleep problems are associated with lower social and academic performance and can have a severe impact on psychological and physical health. Psychotherapists are suppliers within the public health system. The goal of this study was to outline sleep characteristics, prevalence of sleep problems, insomnia, and associations of quality of life among psychotherapists. A total of 774 psychotherapists (74.7% women; mean age 46 years) participated in the study. Sleep characteristics, sleep problems, well-being, life satisfaction and workload, as well as specific job demands, were assessed via a questionnaire. Analyses revealed that more than 4.2% of the surveyed psychotherapists have difficulties falling asleep, 12.7% often wake up in the night, and 26.6% feel tired, and 3.4% think that their interrupted sleep affects work performance. About 44.1% of them suffer from symptoms of insomnia. Path models showed that insomnia is significantly related to well-being and life satisfaction.
Sleep Characteristics, Sleep Problems, and Associations to Quality of Life among Psychotherapists
Schlarb, Angelika A.; Reis, Dorota; Schröder, Annette
2012-01-01
Sleep problems, especially insomnia, are a common complaint among adults. International studies have shown prevalence rates between 4.7 and 36.2% for sleep difficulties in general, whereas 13.1–28.1% report insomnia symptoms. Sleep problems are associated with lower social and academic performance and can have a severe impact on psychological and physical health. Psychotherapists are suppliers within the public health system. The goal of this study was to outline sleep characteristics, prevalence of sleep problems, insomnia, and associations of quality of life among psychotherapists. A total of 774 psychotherapists (74.7% women; mean age 46 years) participated in the study. Sleep characteristics, sleep problems, well-being, life satisfaction and workload, as well as specific job demands, were assessed via a questionnaire. Analyses revealed that more than 4.2% of the surveyed psychotherapists have difficulties falling asleep, 12.7% often wake up in the night, and 26.6% feel tired, and 3.4% think that their interrupted sleep affects work performance. About 44.1% of them suffer from symptoms of insomnia. Path models showed that insomnia is significantly related to well-being and life satisfaction. PMID:23471477
NASA Astrophysics Data System (ADS)
Rivalta, Eleonora
2010-05-01
In the past decades volcano seismologists and geodesists have collected many observations on the transient regime of dike emplacement that current models of dike propagation do not explain. The cause of this failure has been already identified by several authors in the common assumption that magma chambers can maintain their pressure constant while feeding dikes. This assumption collides e.g. with the convex upward shape of the volume evolution during the 1997 dike intrusion at KIlauea, as noted by Owen et al. [2000] and Segall et al. [2001]. Segall et al. [2001] described the flow of the magma from a chamber to a dike with an ordinary differential equation for the unknown pressures of chamber and dike. The feeding of dikes is then associated to a pressure drop in the magma chamber, controlled by magma bulk modulus and elastic compressibility of surrounding rock. Here I present a model developing on that intuition, which makes use of mass conservation (instead of volume conservation) as a constraint for pressure, as magma flows from the chamber to the dike. This ansatz allows to solve the problem analytically. The model predicts that chamber and intrusion volume change exponentially with time as V (t) = V ∞[1 - exp(-t-?)]. Intrusion velocity is found to change as v = v0 exp(-t-?), where v0 is the initial dike velocity. The asymptotic volume V ∞ and the time scale ? can be expressed in terms of rock, magma, chamber and dike parameters and of the initial pressure conditions. Fitting volume or velocity curves can provide independent constraints on parameters difficult to retrieve otherwise. I validate my model with data from the 2000 Miyakejima intrusion (Japan), the 1978 Krafla event (Iceland) and from some intrusions following the 2005 event in Afar (Ethiopia). The fit between model and observations is excellent. This paper confirms and extends the results of a previous study [Rivalta and Segall , 2008] that explained the volume imbalance found during some dike
ERIC Educational Resources Information Center
Berg-Nielsen, Turid Suzanne; Solheim, Elisabet; Belsky, Jay; Wichstrom, Lars
2012-01-01
In this study, we explored informant characteristics as determinants of parent-teacher disagreement on preschoolers' psychosocial problems. Teacher characteristics were included in the analyses, in addition to child and parent factors. Psychosocial problems of 732 4-year olds from a Norwegian community sample were assessed by parents and teachers…
NASA Technical Reports Server (NTRS)
Gorton, C. A.; Lakshminarayana, B.
1980-01-01
The inviscid and viscid effects existing within the passages of a three bladed axial flow inducer operating at a flow coefficient of 0.065 are investigated. The blade static pressure and blade limiting streamline angle distributions were determined and the three components of mean velocity, turbulence intensities, and turbulence stresses were measured at locations inside the inducer blade passage utilizing a rotating three sensor hotwire probe. Applicable equations were derived for the hotwire data reduction analysis and solved numerically to obtain the appropriate flow parameters. The three dimensional inviscid flow in the inducer was predicted by numerically solving the exact equations of motion, and the three dimensional viscid flow was predicted by incorporating the dominant viscous terms into the exact equations. The analytical results are compared with the experimental measurements and design values where appropriate. Radial velocities are found to be of the same order as axial velocities within the inducer passage, confirming the highly three dimensional characteristic of inducer flow. Total relative velocity distribution indicate a substantial velocity deficiency near the tip at mid-passage which expands significantly as the flow proceeds toward the inducer trailing edge. High turbulence intensities and turbulence stresses are concentrated within this core region. Considerable wake diffusion occurs immediately downstream of the inducer trailing edge to decay this loss core. Evidence of boundary layer interactions, blade blockage effects, radially inward flows, annulus wall effects, and backflows are all found to exist within the long, narrow passages of the inducer.
Characteristics of eating and swallowing problems in patients who have dementia with Lewy bodies.
Shinagawa, Shunichiro; Adachi, Hiroyoshi; Toyota, Yasutaka; Mori, Takaaki; Matsumoto, Izumi; Fukuhara, Ryuji; Ikeda, Manabu
2009-06-01
Eating problems occur frequently in patients with dementia, and almost half of all patients with Parkinson's disease have such problems. It has therefore been assumed that eating problems are also common in patients with dementia with Lewy bodies (DLB). However, few systematic studies have investigated eating problems in DLB patients. The aim of this study was to clarify the frequency and characteristics of eating problems in patients with DLB. We examined 29 consecutive patients with DLB and 33 with Alzheimer's disease (AD) in terms of age, sex, education, Mini-mental State Examination, clinical dementia rating (CDR), neuropsychiatric inventory (NPI), Unified Parkinson disease rating scale (UPDRS), fluctuations in cognition, and usage of neuroleptic drugs / antiparkinsonian drugs. We employed a comprehensive questionnaire comprising 40 items and compared the scores between the two groups. DLB patients showed significantly higher scores than AD patients for "difficulty in swallowing foods," "difficulty in swallowing liquids," "coughing or choking when swallowing," "taking a long time to swallow," "suffering from sputum," "loss of appetite," "need watching or help," and "constipation". Only the UPDRS score significantly affected the scores for "difficulty in swallowing foods," "taking a long time to swallow" and "needs watching or help" score, whereas only the NPI score affected the score for "loss of appetite." The scores for UPDRS, NPI and CDR significantly affected the scores for "difficulty in swallowing liquids." No significant independent variables affected the scores for "coughing or choking when swallowing," "suffering from sputum" and "constipation." Although DLB patients show many eating problems, the causes of each problem vary, and the severity of dementia or Parkinsonism is not the only determinant.
Sijtsema, J J; Oldehinkel, A J; Veenstra, R; Verhulst, F C; Ormel, J
2014-06-01
Both structural (i.e., SES, familial psychopathology, family composition) and dynamic (i.e., parental warmth and rejection) family characteristics have been associated with aggressive and depressive problem development. However, it is unclear to what extent (changes in) dynamic family characteristics have an independent effect on problem development while accounting for stable family characteristics and comorbid problem development. This issue was addressed by studying problem development in a large community sample (N = 2,230; age 10-20) of adolescents using Linear Mixed models. Paternal and maternal warmth and rejection were assessed via the Egna Minnen Beträffande Uppfostran for Children (EMBU-C). Aggressive and depressive problems were assessed via subscales of the Youth/Adult Self-Report. Results showed that dynamic family characteristics independently affected the development of aggressive problems. Moreover, maternal rejection in preadolescence and increases in paternal rejection were associated with aggressive problems, whereas decreases in maternal rejection were associated with decreases in depressive problems over time. Paternal and maternal warmth in preadolescence was associated with fewer depressive problems during adolescence. Moreover, increases in paternal warmth were associated with fewer depressive problems over time. Aggressive problems were a stable predictor of depressive problems over time. Finally, those who increased in depressive problems became more aggressive during adolescence, whereas those who decreased in depressive problems became also less aggressive. Besides the effect of comorbid problems, problem development is to a large extent due to dynamic family characteristics, and in particular to changes in parental rejection, which leaves much room for parenting-based interventions.
NASA Technical Reports Server (NTRS)
Hong, D. C.; Langer, J. S.
1986-01-01
An analytic approach to the problem of predicting the widths of fingers in a Hele-Shaw cell is presented. The analysis is based on the WKB technique developed recently for dealing with the effects of surface tension in the problem of dendritic solidification. It is found that the relation between the dimensionless width lambda and the dimensionless group of parameters containing the surface tension, nu, has the form lambda - 1/2 = nu exp 2/3 in the limit of small nu.
NASA Technical Reports Server (NTRS)
Hong, D. C.; Langer, J. S.
1986-01-01
An analytic approach to the problem of predicting the widths of fingers in a Hele-Shaw cell is presented. The analysis is based on the WKB technique developed recently for dealing with the effects of surface tension in the problem of dendritic solidification. It is found that the relation between the dimensionless width lambda and the dimensionless group of parameters containing the surface tension, nu, has the form lambda - 1/2 = nu exp 2/3 in the limit of small nu.
NASA Astrophysics Data System (ADS)
Alhussan, K.; Morozov, D. O.; Stankevich, Yu. A.; Stanchits, L. K.; Stepanov, K. L.
2014-07-01
The thermal properties of hot air needed for describing the hypersonic motion of bodies in the Earth's atmosphere have been considered. Such motion, as is known, is accompanied by the propagation of strong shock waves analogous to waves generated by powerful explosions. Calculations have been made and data banks have been created for the equations of state and thermal characteristics of air in the temperature and density ranges corresponding to velocities of motion of bodies of up to 10 km/s at altitudes of 0-100 km. The formulation of the problem of hypersonic motion in the absence of thermodynamic equilibrium is discussed.
Uniqueness Results for Ill-Posed Characteristic Problems in Curved Space-Times
NASA Astrophysics Data System (ADS)
Ionescu, Alexandru D.; Klainerman, Sergiu
2009-02-01
We prove two uniqueness theorems concerning linear wave equations; the first theorem is in Minkowski space-times, while the second is in the domain of outer communication of a Kerr black hole. Both theorems concern ill-posed Cauchy problems on bifurcate, characteristic hypersurfaces. In the case of the Kerr space-time, the hypersurface is precisely the event horizon of the black hole. The uniqueness theorem in this case, based on two Carleman estimates, is intimately connected to our strategy to prove uniqueness of the Kerr black holes among smooth, stationary solutions of the Einstein-vacuum equations, as formulated in [14].
ERIC Educational Resources Information Center
Oshiro, Claudia Kami Bastos; Kanter, Jonathan; Meyer, Sonia Beatriz
2012-01-01
Functional Analytic Psychotherapy (FAP) is emerging as an effective psychotherapy for psychiatric clinical cases. However, there is little research demonstrating the process of change of FAP. The present study evaluated the introduction and withdrawal of FAP interventions on therapy-interfering verbal behaviors of two participants who were in…
The association of parental characteristics and psychological problems in obese youngsters.
Decaluwé, V; Braet, C; Moens, E; Van Vlierberghe, L
2006-12-01
The aim of the present study was to examine to what extent parental psychological characteristics and parental behavior are related to psychological problems in obese youngsters. Data were collected from 196 families having an overweight youngster (range 10-16 years old) (mean body mass index (BMI)=31.2; s.d.=5.3) seeking weight-loss treatment and compared with data from normal weight samples. Behavior problems were measured using the Child Behavior Checklist; the Child version of the Eating Disorder Examination was used to assess eating disorder psychopathology. Parental psychopathology was measured using the Symptom Checklist-90; parenting behavior was assessed with the Ghent Parental Behavior Scale. Parental psychopathology was prevalent in 59.6% of mothers and 35.7% of fathers. Youngsters exceeding the cutoff for problem behavior ranged between 41.4 and 53.1%. Children's problem behavior was most associated with psychopathology in the mother (r=0.40 for Internalizing and r=0.37 for Externalizing; both P<0.01). The research findings further revealed that the effects of maternal psychopathology were partly mediated by a specific form of parenting behavior, namely Inconsistent discipline, although the effect was stronger for Externalizing behavior (explained variance: 10%) than for Internalizing behavior (explained variance: 4%). No evidence was found for a mediator effect from parenting behavior on the eating disorder symptoms of the obese youngsters. However, several direct relations emerged, suggesting a negative association between a child's eating disorder symptoms and Positive parenting behavior by the mother (r= -0.20 for Eating concern; r= -0.18 for Restraint eating; r= -0.16 for Shape concern; all P<0.05) as well as by the father (r= -0.25 for Eating concern; r= -0.25 for Weight concern; both P<0.01; r= -0.21 for Shape concern; P<0.05). Parental characteristics were associated with psychological problems in obese youngsters, not only in a direct way but
NASA Astrophysics Data System (ADS)
Song, Qing-Wen; Zhang, Yu-Ming; Zhang, Yi-Men; Lü, Hong-Liang; Chen, Feng-Ping; Zheng, Qing-Li
2009-12-01
A new analytical model for reverse characteristics of 4H-SiC merged PN-Schottky diodes (MPS or JBS) is developed. To accurately calculate the reverse characteristics of the 4H-SiC MPS diode, the relationship between the electric field at the Schottky contact and the reverse bias is analytically established by solving the cylindrical Poisson equation after the channel has pinched off. The reverse current density calculated from the Wentzel-Kramers-Brillouin (WKB) theory is verified by comparing it with the experimental result, showing that they are in good agreement with each other. Moreover, the effects of P-region spacing (S) and P-junction depth (Xj) on the characteristics of 4H-SiC MPS are analysed, and are particularly useful for optimizing the design of the high voltage MPS diodes.
Terekhov, Alexander V; Pesin, Yakov B; Niu, Xun; Latash, Mark L; Zatsiorsky, Vladimir M
2010-09-01
We consider the problem of what is being optimized in human actions with respect to various aspects of human movements and different motor tasks. From the mathematical point of view this problem consists of finding an unknown objective function given the values at which it reaches its minimum. This problem is called the inverse optimization problem. Until now the main approach to this problems has been the cut-and-try method, which consists of introducing an objective function and checking how it reflects the experimental data. Using this approach, different objective functions have been proposed for the same motor action. In the current paper we focus on inverse optimization problems with additive objective functions and linear constraints. Such problems are typical in human movement science. The problem of muscle (or finger) force sharing is an example. For such problems we obtain sufficient conditions for uniqueness and propose a method for determining the objective functions. To illustrate our method we analyze the problem of force sharing among the fingers in a grasping task. We estimate the objective function from the experimental data and show that it can predict the force-sharing pattern for a vast range of external forces and torques applied to the grasped object. The resulting objective function is quadratic with essentially non-zero linear terms.
Pesin, Yakov B.; Niu, Xun; Latash, Mark L.
2010-01-01
We consider the problem of what is being optimized in human actions with respect to various aspects of human movements and different motor tasks. From the mathematical point of view this problem consists of finding an unknown objective function given the values at which it reaches its minimum. This problem is called the inverse optimization problem. Until now the main approach to this problems has been the cut-and-try method, which consists of introducing an objective function and checking how it reflects the experimental data. Using this approach, different objective functions have been proposed for the same motor action. In the current paper we focus on inverse optimization problems with additive objective functions and linear constraints. Such problems are typical in human movement science. The problem of muscle (or finger) force sharing is an example. For such problems we obtain sufficient conditions for uniqueness and propose a method for determining the objective functions. To illustrate our method we analyze the problem of force sharing among the fingers in a grasping task. We estimate the objective function from the experimental data and show that it can predict the force-sharing pattern for a vast range of external forces and torques applied to the grasped object. The resulting objective function is quadratic with essentially non-zero linear terms. PMID:19902213
Schlinkmann, K M; Razum, O; Werber, D
2017-04-01
Foodborne disease outbreaks (FBDOs) occur frequently in Europe. Employing analytical epidemiological study designs increases the likelihood of identifying the suspected vehicle(s), but these studies are rarely applied in FBDO investigations. We used multivariable binary logistic regression analysis to identify characteristics of investigated FBDOs reported to the European Food Safety Authority (2007-2011) that were associated with analytical epidemiological evidence (compared to evidence from microbiological investigations/descriptive epidemiology only). The analysis was restricted to FBDO investigations, where the evidence for the suspected vehicle was considered 'strong', i.e. convincing. The presence of analytical epidemiological evidence was reported in 2012 (50%) of these 4038 outbreaks. In multivariable analysis, increasing outbreak size, number of hospitalizations, causative (i.e. aetiological) agent (whether identified and, if so, which one), and the setting in which these outbreaks occurred (e.g. geographically dispersed outbreaks) were independently associated with presence of analytical evidence. The number of investigations with reported analytical epidemiological evidence was unexpectedly high, likely indicating the need for quality assurance within the European Union foodborne outbreak reporting system, and warranting cautious interpretation of our findings. This first analysis of evidence implicating a food vehicle in FBDOs may help to inform public health authorities on when to use analytical epidemiological study designs.
Boev, B V; Semenenko, T A; Bondarenko, V M; Gintsburg, A L
2011-01-01
Structure and modules of computer informational-analytical system "Electronic atlas of Russia" is presented, the object of mapping in this system is epidemiology of socially significant infectious diseases. Systemic information on processes of emergence and spread of socially significant infectious diseases (anthroponoses, zoonoses and sapronoses) in the population of Russian Federation is presented in the atlas. Detailed electronic maps of country territory filled with prognosis-analytical information created by using technological achievements of mathematic and computer modeling of epidemics and outbreaks of viral and bacterial infections are of particular interest. Atlas allows to objectively evaluate the pattern of infection spread, prepare prognoses of epidemic and outbreak developments taking into account the implementation of control measures (vaccination, prophylaxis, diagnostics and therapy) and evaluate their economic effectiveness.
National Helpline for Problem Gambling: A Profile of Its Users' Characteristics
Bastiani, Luca; Fea, Maurizio; Potente, Roberta; Luppi, Claudia; Lucchini, Fabio; Molinaro, Sabrina
2015-01-01
Gambling has seen a significant increase in Italy in the last 10 years and has rapidly become a public health issue, and for these reasons the first National Helpline for Problem Gambling (GR-Helpline) has been established. The aims of this study are to describe the GR-Helpline users' characteristics and to compare the prevalence rates of the users with those of moderate-risk/problematic gamblers obtained from the national survey (IPSAD 2010-2011). Statistical analysis was performed on data obtained from the counselling sessions (phone/e-mail/chat) carried out on 5,805 users (57.5% gamblers; 42.5% families/friends). This confirms that the problems related to gambling concern not only the gamblers but also their families and friends. Significant differences were found between gamblers and families/friends involving gender (74% of gamblers were male; 76.9% of families/friends were female), as well as age-classes and geographical area. Female gamblers had a higher mean age (47.3 versus 40.2 years) and preferred nonstrategy-based games. Prevalence rates of GR-Helpline users and of moderate risk/problematic gamblers were correlated (Rho = 0.58; p = 0.0113). The results highlight the fact that remote access to counselling can be an effective means of promoting treatment for problem gamblers who do not otherwise appeal directly for services. PMID:26064772
NASA Astrophysics Data System (ADS)
Butt, N.; Pidlisecky, A.; Ganshorn, H.; Cockett, R.
2015-12-01
The software company 3 Point Science has developed three interactive learning programs designed to teach, test and practice visualization skills and geoscience concepts. A study was conducted with 21 geoscience students at the University of Calgary who participated in 2 hour sessions of software interaction and written pre and post-tests. Computer and SMART touch table interfaces were used to analyze user interaction, problem solving methods and visualization skills. By understanding and pinpointing user problem solving methods it is possible to reconstruct viewpoints and thought processes. This could allow us to give personalized feedback in real time, informing the user of problem solving tips and possible misconceptions.
Alexandrov, D V; Nizovtseva, I G; Malygin, A P; Huang, H-N; Lee, D
2008-03-19
A model is presented that describes nonstationary solidification of binary melts or solutions from a cooled boundary maintained at a time-dependent temperature. Heat and mass transfer processes are described on the basis of the principles of a mushy layer, which divides pure solid material and a liquid phase. Nonlinear equations characterizing the dynamics of the phase transition boundaries are deduced. Approximate analytical solutions of the model under consideration are constructed. A method for controlling the external temperature at a cooled wall in order to obtain a required solidification velocity is discussed.
Not Available
2006-06-01
In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.
Jaqaman, H.R.
1988-09-01
Overhauser's suggestion that plane-wave orbitals, which yield a homogeneous-density fluid phase, may not correspond to the ground state of nuclear matter is investigated by an approximate analytic method. Wave functions constructed from so-called Overhauser orbitals, which lead to an oscillating-density crystalline solid phase, are shown to yield an energy gain over the plane wave orbitals only at densities well below the saturation density rho/sub 0/approx.0.17 fm/sup -3/. This is in good agreement with previous numerical results. The analytic solution is then generalized to finite temperatures and it is found that the solid phase can survive up to temperatures of approximately 1.1 MeV only. Nuclear matter in the solid phase is similar to an intrinsic semiconductor with an energy gap occurring at the Fermi energy. The gap decreases with the rise in temperature until the melting point is reached where it discontinuously jumps to zero indicating that the transition is of first order.
Tsai, Y.M.; Crane, R.A. )
1992-05-01
Heat transfer across surfaces in imperfect contact occurs in many practical situations. Since the thermal contact conductance problem has appeared in the literature, substantial efforts have been made to estimate the thermal conductance across the interface. Some of the techniques recently developed of estimating thermal contact conductance are based on experimental temperature data at one or several interior positions of the contacting solids and the calculation of the temperature at these locations for known contact conductance. Consequently, an accurate and efficient method for computing temperature distributions because quite important. FDM and FEM are most widely used. However, for most contact conductance computation methods, only the temperatures at the contacting regions and several other positions near the interface need to be determined, so the general FDM and FEM are not particularly efficient in solving this problem. This paper presents an analytical temperature distribution solution to the one-dimensional symmetric system with heat flux on one outside surface and insulation on the other. This analysis provides a theoretical basis for transient measurement of thermal contact conductance. While it is common practice in steady-state measurements to use a water-cooled heat sink, it is possible to limit the transient solution to time interval prior to any detectable temperature increase at the cold end. This effectively eliminates the need for water cooling and permits the use of an insulated boundary. The analytical solution to the mentioned problem obtained shows that for a symmetric system the temperature distribution solution includes two sets of distinct eigenfunctions.
Johnson, Cynthia R; Turner, Kylan; Stewart, Patricia A; Schmidt, Brianne; Shui, Amy; Macklin, Eric; Reynolds, Anne; James, Jill; Johnson, Susan L; Manning Courtney, Patty; Hyman, Susan L
2014-09-01
Many children with autism spectrum disorders (ASD) have co-occurring feeding problems. However, there is limited knowledge about how these feeding habits are related to other behavioral characteristics ubiqitious in ASD. In a relatively large sample of 256 children with ASD, ages 2-11, we examined the relationships between feeding and mealtime behaviors and social, communication, and cognitive levels as well repetitive and ritualistic behaviors, sensory behaviors, and externalizing and internalizing behaviors. Finally, we examined whether feeding habits were predictive of nutritional adequacy. In this sample, we found strong associations between parent reported feeding habits and (1) repetitive and ritualistic behaviors, (2) sensory features, and (3) externalizing and internalizing behavior. There was a lack of association between feeding behaviors and the social and communication deficits of ASD and cognitive levels. Increases in the degree of problematic feeding behaviors predicted decrements in nutritional adequacy.
ERIC Educational Resources Information Center
Baker, Amy J. L.; Archer, Marc; Curtis, Patrick
2007-01-01
This study aimed to determine what youth characteristics were associated with emotional and behavioral problems exhibited within the first three months of placement in residential treatment centers (RTCs) in a sample of youth from 20 agencies in 13 states. Two primary research questions were addressed: 1) What characteristics were associated with…
ERIC Educational Resources Information Center
Baker, Amy J. L.; Archer, Marc; Curtis, Patrick
2007-01-01
This study aimed to determine what youth characteristics were associated with emotional and behavioral problems exhibited within the first three months of placement in residential treatment centers (RTCs) in a sample of youth from 20 agencies in 13 states. Two primary research questions were addressed: 1) What characteristics were associated with…
Berg-Nielsen, Turid Suzanne; Solheim, Elisabet; Belsky, Jay; Wichstrom, Lars
2012-06-01
In this study, we explored informant characteristics as determinants of parent-teacher disagreement on preschoolers' psychosocial problems. Teacher characteristics were included in the analyses, in addition to child and parent factors. Psychosocial problems of 732 4-year olds from a Norwegian community sample were assessed by parents and teachers (CBCL-TRF). Furthermore, teachers reported on their education, experience and relationship to the child. Parental stress and psychopathology were also measured. Teachers rated children considerably lower than their parents did, especially on internalizing problems. When teachers rated more child problems, this was strongly associated with conflict in the teacher-child relationship, which predicted disagreement more than other factors. The highest agreement was on boys' externalizing problems. Girls' behavior was rated much lower by teachers than boys' behavior compared to parents' ratings. Possible teacher perception biases are discussed, such as teacher-child conflict, non-identification of internalizing problems, and same-gender child preference.
NASA Astrophysics Data System (ADS)
Babich, M. D.; Zadiraka, V. K.; Lyudvichenko, V. A.; Sergienko, I. V.
2010-12-01
The use of various opportunities for computation optimization in computer technologies for applied and computational mathematics problems with prescribed quality characteristics is investigated. More precisely, the choice and determination of computational resources and methods of their efficient use for finding an approximate solution of problems up to prescribed accuracy in a limited amount of processor time are investigated.
NASA Astrophysics Data System (ADS)
Dutta, Ivy; Chowdhury, Anirban Roy; Kumbhakar, Dharmadas
2013-03-01
Using Chebyshev power series approach, accurate description for the first higher order (LP11) mode of graded index fibers having three different profile shape functions are presented in this paper and applied to predict their propagation characteristics. These characteristics include fractional power guided through the core, excitation efficiency and Petermann I and II spot sizes with their approximate analytic formulations. We have shown that where two and three Chebyshev points in LP11 mode approximation present fairly accurate results, the values based on our calculations involving four Chebyshev points match excellently with available exact numerical results.
Lorenz, Ralph D
2012-08-01
Thermal drilling has been applied to studies of glaciers on Earth and proposed for study of the martian ice caps and the crust of Europa. Additionally, inadvertent thermal drilling by radioisotope sources released from the breakup of a space vehicle is of astrobiological concern in that this process may form a downward-propagating "warm little pond" that could convey terrestrial biota to a habitable environment. A simple analytic solution to the asymptotic slow-speed case of thermal drilling is noted and used to show that the high thermal conductivity of the low-temperature ice on Europa and Titan makes thermal drilling qualitatively more difficult than at Mars. It is shown that an isolated General Purpose Heat Source (GPHS) "brick" can drill effectively on Earth or Mars, whereas on Titan or Europa with ice at 100 K, the source would stall and become stuck in the ice with a surface temperature of <200 K.
ERIC Educational Resources Information Center
Thorsland, Martin Nils
The purposes of this study were: (1) to evaluate the effectiveness of audio-tutorial (A-T) instruction and (2) to identify, classify and study differences in problem solving approach using a theoretical framework derived from the ideas of D. P. Ausubel. Seventy of 420 students taking a college introductory non-calculus physics course used A-T…
A Meta-Analytic and Qualitative Review of Online versus Face-to-Face Problem-Based Learning
ERIC Educational Resources Information Center
Jurewitsch, Brian
2012-01-01
Problem-based learning (PBL) is an instructional strategy that is poised for widespread application in the current, growing, on-line digital learning environment. While enjoying a track record as a defensible strategy in face-to-face learning settings, the research evidence is not clear regarding PBL in on-line environments. A review of the…
ERIC Educational Resources Information Center
Polito, Vincent A., Jr.
2010-01-01
The objective of this research was to explore the possibilities of identifying knowledge style factors that could be used as central elements of a professional business analyst's (PBA) performance attributes at work for those decision makers that use advanced analytical technologies on decision making tasks. Indicators of knowledge style were…
ERIC Educational Resources Information Center
Polito, Vincent A., Jr.
2010-01-01
The objective of this research was to explore the possibilities of identifying knowledge style factors that could be used as central elements of a professional business analyst's (PBA) performance attributes at work for those decision makers that use advanced analytical technologies on decision making tasks. Indicators of knowledge style were…
Bereketli Zafeirakopoulos, Ilke Erol Genevois, Mujde
2015-09-15
Life Cycle Assessment is a tool to assess, in a systematic way, the environmental aspects and its potential environmental impacts and resources used throughout a product's life cycle. It is widely accepted and considered as one of the most powerful tools to support decision-making processes used in ecodesign and sustainable production in order to learn about the most problematic parts and life cycle phases of a product and to have a projection for future improvements. However, since Life Cycle Assessment is a cost and time intensive method, companies do not intend to carry out a full version of it, except for large corporate ones. Especially for small and medium sized enterprises, which do not have enough budget for and knowledge on sustainable production and ecodesign approaches, focusing only on the most important possible environmental aspect is unavoidable. In this direction, finding the right environmental aspect to work on is crucial for the companies. In this study, a multi-criteria decision-making methodology, Analytic Network Process is proposed to select the most relevant environmental aspect. The proposed methodology aims at providing a simplified environmental assessment to producers. It is applied for a hand blender, which is a member of the Electrical and Electronic Equipment family. The decision criteria for the environmental aspects and relations of dependence are defined. The evaluation is made by the Analytic Network Process in order to create a realistic approach to inter-dependencies among the criteria. The results are computed via the Super Decisions software. Finally, it is observed that the procedure is completed in less time, with less data, with less cost and in a less subjective way than conventional approaches. - Highlights: • We present a simplified environmental assessment methodology to support LCA. • ANP is proposed to select the most relevant environmental aspect. • ANP deals well with the interdependencies between aspects and
NASA Astrophysics Data System (ADS)
Bashiri, Mahdi; Karimi, Hossein
2012-07-01
Quadratic assignment problem (QAP) is a well-known problem in the facility location and layout. It belongs to the NP-complete class. There are many heuristic and meta-heuristic methods, which are presented for QAP in the literature. In this paper, we applied 2-opt, greedy 2-opt, 3-opt, greedy 3-opt, and VNZ as heuristic methods and tabu search (TS), simulated annealing, and particle swarm optimization as meta-heuristic methods for the QAP. This research is dedicated to compare the relative percentage deviation of these solution qualities from the best known solution which is introduced in QAPLIB. Furthermore, a tuning method is applied for meta-heuristic parameters. Results indicate that TS is the best in 31%of QAPs, and the IFLS method, which is in the literature, is the best in 58 % of QAPs; these two methods are the same in 11 % of test problems. Also, TS has a better computational time among heuristic and meta-heuristic methods.
NASA Astrophysics Data System (ADS)
Trifonenkov, A. V.; Trifonenkov, V. P.
2017-01-01
This article deals with a feature of problems of calculating time-average characteristics of nuclear reactor optimal control sets. The operation of a nuclear reactor during threatened period is considered. The optimal control search problem is analysed. The xenon poisoning causes limitations on the variety of statements of the problem of calculating time-average characteristics of a set of optimal reactor power off controls. The level of xenon poisoning is limited. There is a problem of choosing an appropriate segment of the time axis to ensure that optimal control problem is consistent. Two procedures of estimation of the duration of this segment are considered. Two estimations as functions of the xenon limitation were plot. Boundaries of the interval of averaging are defined more precisely.
Drugli, May Britt; Fossum, Sturla; Larsson, Bo; Morch, Willy-Tore
2010-07-01
In the present study, predictors of persistent conduct problems among children aged 4-8 years were investigated in a randomized controlled trial 1 year after treatment with the Incredible Years parent training program (PT), or combined parent training and child treatment (PT + CT). Data were collected before and after treatment and at a 1-year follow-up. Pre-treatment child characteristics predicting persistent conduct problems in the child at the 1-year follow-up were high levels of internalizing and aggression problems as reported by mothers. The only family characteristic predicting persistence of child conduct problems was having contacts with child protection services. Clinicians and researchers need to closely monitor and identify children with conduct problems not responding to parent training programs. These individuals and their families are likely to need further support.
NASA Technical Reports Server (NTRS)
Longuski, James M.; Mcronald, Angus D.
1988-01-01
In previous work the problem of injecting the Galileo and Ulysses spacecraft from low earth orbit into their respective interplanetary trajectories has been discussed for the single stage (Centaur) vehicle. The central issue, in the event of spherically distributed injection errors, is what happens to the vehicle? The difficulties addressed in this paper involve the multi-stage problem since both Galileo and Ulysses will be utilizing the two-stage IUS system. Ulysses will also include a third stage: the PAM-S. The solution is expressed in terms of probabilities for total percentage of escape, orbit decay and reentry trajectories. Analytic solutions are found for Hill's Equations of Relative Motion (more recently called Clohessy-Wiltshire Equations) for multi-stage injections. These solutions are interpreted geometrically on the injection sphere. The analytic-geometric models compare well with numerical solutions, provide insight into the behavior of trajectories mapped on the injection sphere and simplify the numerical two-dimensional search for trajectory families.
NASA Astrophysics Data System (ADS)
Chang, Guobin; Xu, Tianhe; Wang, Qianxin; Zhang, Shubi; Chen, Guoliang
2017-05-01
The symmetric Helmert transformation model is widely used in geospatial science and engineering. Using an analytical least-squares solution to the problem, a simple and approximate error analysis is developed. This error analysis follows the Pope procedure solving nonlinear problems, but no iteration is needed here. It is simple because it is not based on the direct and cumbersome error analysis of every single process involved in the analytical solution. It is approximate because it is valid only in the first-order approximation sense, or in other words, the error analysis is performed approximately on the tangent hyperplane at the estimates instead of the original nonlinear manifold of the observables. Though simple and approximate, this error analysis's consistency is not sacrificed as can be validated by Monte Carlo experiments. So the practically important variance-covariance matrix, as a consistent accuracy measure of the parameter estimate, is provided by the developed error analysis. Further, the developed theory can be easily generalized to other cases with more general assumptions about the measurement errors.
NASA Astrophysics Data System (ADS)
Delshams, Amadeu; Gidea, Marian; Roldan, Pablo
2016-11-01
We consider the spatial circular restricted three-body problem, on the motion of an infinitesimal body under the gravity of Sun and Earth. This can be described by a 3-degree of freedom Hamiltonian system. We fix an energy level close to that of the collinear libration point L1, located between Sun and Earth. Near L1 there exists a normally hyperbolic invariant manifold, diffeomorphic to a 3-sphere. For an orbit confined to this 3-sphere, the amplitude of the motion relative to the ecliptic (the plane of the orbits of Sun and Earth) can vary only slightly. We show that we can obtain new orbits whose amplitude of motion relative to the ecliptic changes significantly, by following orbits of the flow restricted to the 3-sphere alternatively with homoclinic orbits that turn around the Earth. We provide an abstract theorem for the existence of such 'diffusing' orbits, and numerical evidence that the premises of the theorem are satisfied in the three-body problem considered here. We provide an explicit construction of diffusing orbits. The geometric mechanism underlying this construction is reminiscent of the Arnold diffusion problem for Hamiltonian systems. Our argument, however, does not involve transition chains of tori as in the classical example of Arnold. We exploit mostly the 'outer dynamics' along homoclinic orbits, and use very little information on the 'inner dynamics' restricted to the 3-sphere. As a possible application to astrodynamics, diffusing orbits as above can be used to design low cost maneuvers to change the inclination of an orbit of a satellite near L1 from a nearly-planar orbit to a tilted orbit with respect to the ecliptic. We explore different energy levels, and estimate the largest orbital inclination that can be achieved through our construction.
NASA Technical Reports Server (NTRS)
Gorton, C. A.; Lakshminarayana, B.
1974-01-01
The effort conducted to gather additional understanding of the complex inviscid and viscid effects existing within the passages of a three-bladed axial flow inducer operating at a flow coefficient of 0.065 is summarized. The experimental investigations included determination of the blade static pressure and blade limiting streamline angle distributions, and measurement of the three components of mean velocity, turbulence intensities and turbulence stresses at locations inside the inducer blade passage utilizing a rotating three-sensor hotwire probe. Applicable equations were derived for the hotwire data reduction analysis and solved numerically to obtain the appropriate flow parameters. Analytical investigations were conducted to predict the three-dimensional inviscid flow in the inducer by numerically solving the exact equations of motion, and to approximately predict the three-dimensional viscid flow by incorporating the dominant viscous terms into the exact equations. The analytical results are compared with the experimental measurements and design values where appropriate.
Characteristics and gender differences among self-excluded casino problem gamblers: Missouri data.
Nower, Lia; Blaszczynski, Alex
2006-01-01
The present study explores gender-related differences in the demographic and gambling-related characteristics of 2670 problem gamblers participating in a state-administered (Missouri) casino self-exclusion program between 2001 and 2003. Female (n=1298, 48.4%) and male (n=1372, 51.1%) participants ranged in age from 21 to 84 years. Gender-related differences were noted among demographic variables, patterns of gambling behavior, reasons for self-exclusion, and involvement in self-help, counseling, and bankruptcy services. Female self-excluders were more likely than males to be older at time of application, African American, and either retired, unemployed or otherwise outside the traditional workforce. In addition, female self-excluders were more likely to report a later age of gambling onset, a shorter period between onset and self-exclusion, a preference for non-strategic forms of gambling and prior bankruptcy. The main predictors for female participation in self-exclusion included a desire to gain control and prevent suicide and referral by a counselor. The desire to save the marriage was a motivating factor for all participants. Findings suggest that the most efficacious treatment strategies with this group will include family systemic therapy and financial management in addition to pharmaco-treatment and culturally-sensitive individual therapy.
Bifocal contact lenses: History, types, characteristics, and actual state and problems
Toshida, Hiroshi; Takahashi, Kozo; Sado, Kazushige; Kanai, Atsushi; Murakami, Akira
2008-01-01
Since people who wear contact lenses (CL) often continue using CL even when they develop presbyopia, there are growing expectations for bifocal CL. To understand actual state and problems, history, types, and their characteristics are summarized in this review. Bifocal CL have a long history over 70 years. Recently, bifocal CL have achieved remarkable progress. However, there still is an impression that prescription of bifocal CL is not easy. It should also be remembered that bifocal CL have limits, including limited addition for near vision, as well as the effects of aging and eye diseases in the aged, such as dry eye, astigmatism, cataract, etc. Analysis of the long-term users of bifocal CL among our patients has revealed the disappearance of bifocal CL that achieved unsatisfactory vision and poor contrast compared with those provided by other types of CL. Changing the prescription up to 3 times for lenses of the same brand may be appropriate. Lenses that provide poor contrast sensitivity, suffer from glare, or give unsatisfactory vision have been weeded out. The repeated replacement of products due to the emergence of improved or new products will be guessed. PMID:19668441
Characteristics of fluent skills in a complex, dynamic problem-solving task.
Sohn, Myeong-Ho; Douglass, Scott A; Chen, Mon-Chu; Anderson, John R
2005-01-01
We examined critical characteristics of fluent cognitive skills, using the Georgia Tech Aegis Simulation Program, a tactical decision-making computer game that simulates tasks of an anti-air-warfare coordinator. To characterize learning, we adopted the unit-task analysis framework, in which a task is decomposed into several unit tasks that are further decomposed into functional-level subtasks. Our results showed that learning at a global level could be decomposed into learning smaller component tasks. Further, most learning was associated with a reduction in cognitive processes, in which people make inferences from the currently available information. Eye-movement data also revealed that the time spent on task-irrelevant regions of the display decreased more than did the time spent on task-relevant regions. In sum, although fluency in dynamic, complex problem solving was achieved by attaining efficiency in perceptual, motor, and cognitive processes, the magnitude of the gains depended on the preexisting fluency of the component skills. These results imply that a training program should decompose a task into its component skills and emphasize those components with which trainees have relatively little prior experience. Actual or potential applications of this research include learning and training of complex tasks as well as evaluation of performance on those tasks.
Guneser, Onur; Zorba, Murat
2014-06-01
Tahin helva is one of Turkish traditional confectionary foods. Sesame paste, sugar syrup and soapwort extract were used for tahin helva's production. The purpose of this study was to solve the oil separation problem occurred in tahin helva by using food additives permitted as an emulsifier for tahin helva in the Turkish and EU Codex. Sorbitan tristearate (STS), sorbitan monopalmitate (SMP) and their combinations (STS:SMP, 1:1) were added to tahin helva, then helva samples were stored at the storage temperatures of 20 °C, 30 °C, and 40 °C. The emulsifiers did not have any effect on physical, chemical and sensory properties of tahin helva except on its oil content, whereas storage temperature and storage time had effects on those properties of helva. STS:SMP combination was found to be statistically more effective than SMP and STS formulations in preventing oil separation. Penetration force of tahin helva has increased by increasing the storage temperature and storage time. It was found that there was a decrease in -a colour value of helva through the storage time at 20 °C and 30 °C, while there was an increase in that value at 40 °C. The highest change in the moisture content of all helva samples through storage was observed at the storage temperature of 20 °C. Sensory scores for appearance, texture and flavour characteristics of helva have decreased significantly during the storage period.
Analytical Production and Collimation of Astrophysical Jets
NASA Astrophysics Data System (ADS)
Bernal, C. G.; Lee, W. H.
2005-09-01
The structure and evolution of jet-like structures under a variety of physical conditions is a problem that generally requires numerical modelling. However, in certain cases valuable insight can be gained from purely hydrodynamical analytical solutions which exhibit outflows of varying characteristics. We show here several solutions of this type, applicable to various accretion scenarios.
Lubman, Dan I; Garfield, Joshua B B; Manning, Victoria; Berends, Lynda; Best, David; Mugavin, Janette M; Lam, Tina; Buykx, Penny; Larner, Andrew; Lloyd, Belinda; Room, Robin; Allsop, Steve
2016-07-19
People seeking treatment for substance use disorders often have additional health and social issues. Although individuals presenting with alcohol as the primary drug of concern (PDOC) account for nearly half of all treatment episodes to the Australian alcohol and other drug (AOD) service system, previous treatment cohort studies have focused only on the profile of Australian heroin or methamphetamine users. While studies overseas indicate that clients seeking treatment primarily for their drinking are less likely to experience social and economic marginalisation than those seeking treatment primarily for illicit or pharmaceutical drug use, very little research has directly compared individuals presenting with alcohol as the PDOC to those primarily presenting with other drugs as their PDOC. Seven hundred and ninety-six participants were recruited at entry to specialist AOD treatment in Victoria and Western Australia, and completed measures of demographic and social factors, substance use, quality of life, service use, and criminal justice involvement. We compared those with alcohol as their PDOC to those with other drugs as their PDOC using Pearson chi-square and Mann-Whitney U tests. Rates of social disadvantage, poor quality of life, high severity of substance dependence, and past-year AOD, mental health, acute health, and social service use were high in all groups. However, participants with alcohol as the PDOC were older; more likely to have an educational qualification; less likely to report criminal justice involvement, housing/homelessness service use, tobacco smoking, or problems with multiple substances; and reported better environmental quality of life; but were more likely to have used ambulance services, than those with other drugs as their PDOC. While those seeking treatment primarily for alcohol problems appear less likely to suffer some forms of social and economic disadvantage or to use multiple substances than those with a primary drug problem, they
Owen, William E; Rawlins, Mindy L; Roberts, William L
2010-08-05
Serum testosterone measurements have utility in diagnosis of clinical conditions characterized by both increased and decreased testosterone concentrations. Studies have indicated that testosterone immunoassays may give inaccurate results for women and children. We evaluated the performance of a second generation testosterone immunoassay from Roche Diagnostics. Testo II performed on a Modular Analytics E 170 analyzer is an automated random access electrochemiluminometric assay. We evaluated limit of blank (LoB), imprecision, linearity, interference, and method comparison with liquid chromatography-tandem mass spectrometry assay (LC-MS/MS). Method comparison included the current generation Roche testosterone assay (Testo I) and the Access 2 testosterone chemiluminometric assay (Beckman Coulter). Results for men and women were analyzed for analytic concordance. The relative % differences of immunoassay compared to LC-MS/MS results were evaluated. The LoB was 0.07nmol/l. Total imprecision was <6%. The assay was linear from 0.2 to 46.6nmol/l. Negative interference was observed for lipemia at concentrations >22.5g/l. Analytic concordance showed improved specificity for women. Comparison of results to LC-MS/MS indicated comparable performance with other immunoassays for men and improved performance for women, boys, and girls with mean differences of 0.5%, -0.7%, and 24.4%, respectively. The Roche Testo II assay demonstrated excellent precision. Comparison to 2 other automated immunoassays showed comparable performance for men and improved performance for women and children. However, challenges still exist for quantifying testosterone concentrations <10.4nmol/l for men and <1.7nmol/l for women and children by immunoassay. Copyright 2010 Elsevier B.V. All rights reserved.
Pauli, Daniela; Seyfarth, Michael; Dibbelt, Leif
2005-01-01
Applying basic potentiometric and photometric assays, we evaluated the fully automated random access chemistry analyzer Architect c8000, a new member of the Abbott Architect system family, with respect to both its analytical and operational performance and compared it to an established high-throughput chemistry platform, the Abbott Aeroset. Our results demonstrate that intra- and inter-assay imprecision, inaccuracy, lower limit of detection and linear range of the c8000 generally meet actual requirements of laboratory diagnosis; there were only rare exceptions, e.g. assays for plasma lipase or urine uric acid which apparently need to be improved by additional rinsing of reagent pipettors. Even with plasma exhibiting CK activities as high as 40.000 U/l, sample carryover by the c8000 could not be detected. Comparison of methods run on the c8000 and the Aeroset revealed correlation coefficients of 0.98-1.00; if identical chemistries were applied on both analyzers, slopes of regression lines approached unity. With typical laboratory workloads including 10-20% STAT samples and up to 10% samples with high analyte concentrations demanding dilutional reruns, steady-state throughput numbers of 700 to 800 tests per hour were obtained with the c8000. The system generally responded to STAT orders within 2 minutes yielding analytical STAT order completion times of 5 to 15 minutes depending on the type and number of assays requested per sample. Due to its extended test and sample processing capabilities and highly comfortable software, the c8000 may meet the varying needs of clinical laboratories rather well.
NASA Astrophysics Data System (ADS)
Liang, Dong; Fu, Kai; Wang, Wenqia
2016-11-01
In this paper, a splitting characteristic method is developed for solving general multi-component aerosol transports in atmosphere, which can efficiently compute the aerosol transports by using large time step sizes. The proposed characteristic finite difference method (C-FDM) can solve the multi-component aerosol distributions in high dimensional domains over large ranges of concentrations and for different aerosol types. The C-FDM is first tested to compute the moving of a Gaussian concentration hump. Comparing with the Runge-Kutta method (RKM), our C-FDM can use very large time step sizes. Using Δt = 0.1, the accuracy of our C-FDM is 10-4, but the RKM only gets the accuracy of 10-2 using a small Δt = 0.01 and the accuracy of 10-3 even using a much smaller Δt = 0.002. A simulation of sulfate transport in a varying wind field is then carried out by the splitting C-FDM, where the sulfate pollution is numerically showed expanding along the wind direction and the effects of the different time step sizes and different wind speeds are analyzed. Further, a realistic multi-component aerosol transport over an area in northeastern United States is studied. Concentrations of PM2.5 sulfate, ammonium, nitrate are high in the urban area, and low in the marine area, while sea salts of sodium and chloride mainly exist in the marine area. The normalized mean bias and the normalized mean error of the predicted PM2.5 concentrations are -6.5% and 24.1% compared to the observed data measured at monitor stations. The time series of numerical aerosol concentration distribution show that the strong winds can move the aerosol concentration peaks horizontally for a long distance, such as from the urban area to the rural area and from the marine area to the urban and rural area. Moreover, we also show the numerical time duration patterns of the aerosol concentration distributions due to the affections of the turbulence and the deposition removal. The developed splitting C-FDM algorithm
NASA Astrophysics Data System (ADS)
Tsuji, Mineo; Xu, Fujin; Tsuruda, Yasutaka; Hamasaki, Shin-Ichi
We have proposed a current-observer-based speed-sensorless vector control system that is in a rotating reference frame and takes into account iron loss. By deriving a linear model and by computing the trajectories of poles and zeros, the system stability on various parameters such as operating points, observer gain, controller gain and stator resistance has been investigated. Furthermore, an exact analytical model including PWM control, dead time and non-ideal features of power devices is developed. The characteristic improvement and stability limit of the proposed system are discussed by simulation and experiment.
Mishra, Shailendra Kumar; Dasgupta, Doyel; Ray, Subha
2016-02-27
The present study aims to understand the relationship of socioeconomic characteristics, menstrual hygiene practices and gynaecological problems among adolescent girls residing in rural and urban areas in the state of West Bengal, India. The study was based on a sample of 715 adolescent girls from rural (325) and urban (390) areas of West Bengal, a state in Eastern India. These girls belong to the Bengali-speaking Hindu community. Data on socioeconomic characteristics, menstrual hygiene practices (such as type of absorbents used and mode of cleaning of genitals during days of menstrual discharge) and gynaecological problems were collected using pretested questionnaires. Rural and urban girls differ (p<0.01) for age at menarche, menstrual hygiene practices and prevalence of gynaecological problems. Urban girls have better menstrual hygiene practices (β=0.343, p<0.01) than rural girls. A similar trend is noted for gynaecological problems (β=0.080, p<0.01) among the study participants. Apart from socioeconomic characteristics, menstrual hygiene (β=-0.121, p<0.01) remains a significant predictor of gynaecological problems. The results of path analysis also indicate that girls of higher socioeconomic status have better menstrual hygiene practices which subsequently reduce the prevalence of gynaecological problems among them. A concerted effort from parents, educational institutions and existing healthcare institutions along with media may ensure safe and secure reproductive health prospects for adolescents in the region.
Åkerstedt, Torbjörn; Kecklund, Göran
2017-03-01
The purpose was to investigate which detailed characteristics of shift schedules that are seen as problems to those exposed. A representative national sample of non-day workers (N = 2031) in Sweden was asked whether they had each of a number of particular work schedule characteristics and, if yes, to what extent this constituted a "big problem in life". It was also inquired whether the individual's work schedules had negative consequences for fatigue, sleep and social life. The characteristic with the highest percentage reporting a big problem was "short notice (<1 month) of a new work schedule" (30.5%), <11 h off between shifts (27.8%), and split duty (>1.5 h break at mid-shift, 27.2%). Overtime (>10 h/week), night work, morning work, day/night shifts showed lower prevalences of being a "big problem". Women indicated more problems in general. Short notice was mainly related to negative social effects, while <11 h off between shifts was related to disturbed sleep, fatigue and social difficulties. It was concluded that schedules involving unpredictable working hours (short notice), short daily rest between shifts, and split duty shifts constitute big problems. The results challenge current views of what aspects of shift work need improvement, and negative social consequences seem more important than those related to health.
NASA Technical Reports Server (NTRS)
Sutliff, Daniel L.; Walker, Bruce E.
2014-01-01
An Ultrasonic Configurable Fan Artificial Noise Source (UCFANS) was designed, built, and tested in support of the NASA Langley Research Center's 14x22 wind tunnel test of the Hybrid Wing Body (HWB) full 3-D 5.8% scale model. The UCFANS is a 5.8% rapid prototype scale model of a high-bypass turbofan engine that can generate the tonal signature of proposed engines using artificial sources (no flow). The purpose of the program was to provide an estimate of the acoustic shielding benefits possible from mounting an engine on the upper surface of a wing; a flat plate model was used as the shielding surface. Simple analytical simulations were used to preview the radiation patterns - Fresnel knife-edge diffraction was coupled with a dense phased array of point sources to compute shielded and unshielded sound pressure distributions for potential test geometries and excitation modes. Contour plots of sound pressure levels, and integrated power levels, from nacelle alone and shielded configurations for both the experimental measurements and the analytical predictions are presented in this paper.
Behaviour-Emotional Characteristics of Primary-School Children Rated as Having Language Problems
ERIC Educational Resources Information Center
Lundervold, A. J.; Heimann, M.; Manger, T.
2008-01-01
Background: Primary-school teachers are expected to detect problems related to language function, but the teachers' evaluations may be heavily influenced by gender and classroom behaviour. Aim: To investigate the relationship between language problems (LPs) and behaviour-emotional problems as rated by primary-school teachers. Methods: All…
Behaviour-Emotional Characteristics of Primary-School Children Rated as Having Language Problems
ERIC Educational Resources Information Center
Lundervold, A. J.; Heimann, M.; Manger, T.
2008-01-01
Background: Primary-school teachers are expected to detect problems related to language function, but the teachers' evaluations may be heavily influenced by gender and classroom behaviour. Aim: To investigate the relationship between language problems (LPs) and behaviour-emotional problems as rated by primary-school teachers. Methods: All…
NASA Technical Reports Server (NTRS)
Murphy, A. C.
1981-01-01
Experimental data and correlative analytical results on the flutter and gust response characteristics of a torsion-free-wing (TFW) fighter airplane model are presented. TFW consists of a combined wing/boom/canard surface and was tested with the TFW free to pivot in pitch and with the TFW locked to the fuselage. Flutter and gust response characteristics were measured in the Langley Transonic Dynamics Tunnel with the complete airplane model mounted on a cable mount system that provided a near free flying condition. Although the lowest flutter dynamic pressure was measured for the wing free configuration, it was only about 20 deg less than that for the wing locked configuration. However, no appreciable alleviation of the gust response was measured by freeing the wing.
NASA Astrophysics Data System (ADS)
Zemskov, Serguey V.; Jonkers, Henk M.; Vermolen, Fred J.
The present study is performed in the framework of the investigation of the potential of bacteria to act as a catalyst of the self-healing process in concrete, i.e. their ability to repair occurring cracks autonomously. Spherical clay capsules containing the healing agent (calcium lactate) are embedded in the concrete structure. Water entering a freshly formed crack releases the healing agent and activates the bacteria which will seal the crack through the process of metabolically mediated calcium carbonate precipitation. In the paper, an analytic formalism is developed for the computation of the probability that a crack hits an encapsulated particle, i.e. the probability that the self-healing process starts. Most computations are performed in closed algebraic form in the computer algebra system Mathematica which allows to perform the last step of calculations numerically with a higher accuracy.
ERIC Educational Resources Information Center
Ozgen, Kemal; Alkan, Huseyin
2012-01-01
The present study examined the potential relationship between 1st and 5th year secondary school pre-service mathematics teachers' skills in understanding, method, modelling, verification, and extension dimensions of problem solving and their learning style characteristics. The data consisted of the skills pre-service teachers demonstrated in the…
USDA-ARS?s Scientific Manuscript database
A novel hybrid muskmelon has been bred specifically for use by the fresh-cut industry in winter. Quality characteristics of fresh-cut chunks from the hybrid were compared to those of its inbred parental lines and to those of a commercial netted muskmelon (cantaloupe) and a non-netted muskmelon (hon...
NASA Technical Reports Server (NTRS)
Thompson, W. C.; Boghani, A. B.; Leland, T. J. W.
1977-01-01
An investigation was conducted to compare the steady-state and dynamic flow characteristics of an axial-flow fan which had been used previously as the air supply fan for some model air cushion landing system studies. Steady-state flow characteristics were determined in the standard manner by using differential orifice pressures for the flow regime from free flow to zero flow. In this same regime, a correlative technique was established so that fan inlet and outlet pressures could be used to measure dynamic flow as created by a rotating damper. Dynamic tests at damper frequencies up to 5 Hz showed very different flow characteristics when compared with steady-state flow, particularly with respect to peak pressures and the pressure-flow relationship at fan stall and unstall. A generalized, rational mathematical fan model was developed based on physical fan parameters and a steady-state flow characteristic. The model showed good correlation with experimental tests at damper frequencies up to 5 Hz.
Strunk, Kathleen C; Strunk, Kamden K
2012-09-01
The purpose of this study was to determine how personality characteristics, sense of organizational empowerment, and job satisfaction combine to predict turnover intention among a population of Sexual Assault Nurse Examiners (SANEs). Data were collected from 161 SANEs from 23 SANE organizations across the central and west United States through standardized tools and a demographic questionnaire. Both personality, namely agreeableness and workplace characteristics, particularly perceived empowerment and job satisfaction, combine to predict intention to leave the job of these sampled SANEs. One particularly curious finding was the positive prediction of agreeableness on turnover intention - that is, more agreeable people would be more likely to leave their jobs as SANEs. Professionals can gain insight from the path analysis results that show the need to address both personal and organizational factors in mitigating turnover intention among SANEs. This appears to be particularly true in providing a sense of empowerment and opportunity within the organization. © 2012 International Association of Forensic Nurses.
Chahine, G.L.; Genoux, P.F.; Johnson, V.E. Jr.; Frederick, G.S.
1984-09-01
Waterjet nozzles (STRATOJETS) have been developed which achieve passive structuring of cavitating submerged jets into discrete ring vortices, and which possess cavitation incipient numbers six times higher than obtained with conventional cavitating jet nozzles. In this study we developed analytical and numerical techniques and conducted experimental work to gain an understanding of the basic phenomena involved. The achievements are: (1) a thorough analysis of the acoustic dynamics of the feed pipe to the nozzle; (2) a theory for bubble ring growth and collapse; (3) a numerical model for jet simulation; (4) an experimental observation and analysis of candidate second-generation low-sigma STRATOJETS. From this study we can conclude that intensification of bubble ring collapse and design of highly resonant feed tubes can lead to improved drilling rates. The models here described are excellent tools to analyze the various parameters needed for STRATOJET optimizations. Further analysis is needed to introduce such important factors as viscosity, nozzle-jet interaction, and ring-target interaction, and to develop the jet simulation model to describe the important fine details of the flow field at the nozzle exit.
Characteristics of a Cognitive Tool That Helps Students Learn Diagnostic Problem Solving
ERIC Educational Resources Information Center
Danielson, Jared A.; Mills, Eric M.; Vermeer, Pamela J.; Preast, Vanessa A.; Young, Karen M.; Christopher, Mary M.; George, Jeanne W.; Wood, R. Darren; Bender, Holly S.
2007-01-01
Three related studies replicated and extended previous work (J.A. Danielson et al. (2003), "Educational Technology Research and Development," 51(3), 63-81) involving the Diagnostic Pathfinder (dP) (previously Problem List Generator [PLG]), a cognitive tool for learning diagnostic problem solving. In studies 1 and 2, groups of 126 and 113…
ERIC Educational Resources Information Center
Matson, Johnny L.; Horovitz, Max; Sipes, Megan
2011-01-01
The prevalence of toileting problems was assessed in 153 adults with intellectual disability (ID) using the "Profile of Toileting Issues" ("POTI") and comparisons were made based on various demographic variables. The most frequently endorsed problems were "has toileting accidents during the day," "has toileting…
Characteristics of a Cognitive Tool That Helps Students Learn Diagnostic Problem Solving
ERIC Educational Resources Information Center
Danielson, Jared A.; Mills, Eric M.; Vermeer, Pamela J.; Preast, Vanessa A.; Young, Karen M.; Christopher, Mary M.; George, Jeanne W.; Wood, R. Darren; Bender, Holly S.
2007-01-01
Three related studies replicated and extended previous work (J.A. Danielson et al. (2003), "Educational Technology Research and Development," 51(3), 63-81) involving the Diagnostic Pathfinder (dP) (previously Problem List Generator [PLG]), a cognitive tool for learning diagnostic problem solving. In studies 1 and 2, groups of 126 and 113…
Against All Odds: Problem-Solving Strategies and Behavioural Characteristics of Novice Students
ERIC Educational Resources Information Center
Chang, Pei-Fen; Lin, Miao-Chen
2015-01-01
This study investigates problem-solving difficulties of novices in a classroom setting, using a German instructional tool, the Fischertechnik kit of approximately 400 parts. In order to analyse the students' thinking processes as they solved the problems, verbal protocol analysis (VPA) was used to record the students'' thinking processes and…
ERIC Educational Resources Information Center
Matson, Johnny L.; Horovitz, Max; Sipes, Megan
2011-01-01
The prevalence of toileting problems was assessed in 153 adults with intellectual disability (ID) using the "Profile of Toileting Issues" ("POTI") and comparisons were made based on various demographic variables. The most frequently endorsed problems were "has toileting accidents during the day," "has toileting…
Benito, Ángel; Calderón, Fernando; Benito, Santiago
2016-12-18
The most common way to produce red wine is through the use of Saccharomyces cerevisiae strains for alcoholic fermentation and lactic acid bacteria for malolactic fermentation. This traditional winemaking methodology produces microbiologically stable red wines. However, under specific conditions off-flavours can occur, wine quality can suffer and human health problems are possible, especially after the second fermentation by the lactic acid bacteria. In warm countries, problems during the malolactic fermentation arise because of the high pH of the must, which makes it very difficult to properly control the process. Under such conditions, wines with high acetic acid and histamine concentrations are commonly produced. This study investigates a recent red wine-making technology that uses a combination of Lachancea thermotolerans and Schizosaccharomyces pombe as an alternative to the conventional malolactic fermentation. This work studies new parameters such as aroma compounds, amino acids, ethanol index and sensory evaluation. Schizosaccharomyces pombe totally consumes malic acid while Lachancea thermotolerans produces lactic acid, avoiding excessive deacidification of musts with low acidity in warm viticulture areas. This methodology also reduces the malolactic fermentation hazards in wines with low acidity. The main products are wines that contain less acetic acid, less biogenic amines and precursors and less ethyl carbamate precursors than the traditional wines produced via conventional fermentation techniques.
EPA’s Web Analytics Program collects, analyzes, and provides reports on traffic, quality assurance, and customer satisfaction metrics for EPA’s website. The program uses a variety of analytics tools, including Google Analytics and CrazyEgg.
Gender differences in characteristics of Chinese treatment-seeking problem gamblers.
Tang, Catherine So-kum; Wu, Anise M S; Tang, Joe Y C
2007-06-01
A total of 952 (841 men and 111 women) Chinese treatment-seeking problem gamblers completed self-report assessment forms. Female in contrast to male gamblers were more likely to be older, married, less educated, and without employment. Female gamblers also started gambling at an older age, had a shorter gambling history, preferred casino and mahjong gambling, and reported more somatic complaints and suicidal thoughts. Male and female gamblers accumulated similar amount of gambling debt and reported an average of 12 gambling-related problems on the Chinese version of the South Oaks Gambling Screen [Lesieur and Blume (Am J Psychiatry 144:1184-1188, 1987)]. Both groups were similarly troubled by their indebtedness, inability to control gambling, and gambling-related interpersonal problems. However, female gamblers had fewer means to pay their gambling debt. Given that significant gender-related differences were observed in Chinese problem gamblers, prevention and treatment services should attend to specific needs of male and female gamblers.
Velychko, T P; Soldatkin, О О; Melnyk, V G; Marchenko, S V; Kirdeciler, S K; Akata, B; Soldatkin, A P; El'skaya, A V; Dzyadevych, S V
2016-12-01
Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05-15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis.
Holzhauser, Thomas; Ree, Ronald van; Poulsen, Lars K; Bannon, Gary A
2008-10-01
There is detailed guidance on how to perform bioinformatic analyses and enzymatic degradation studies for genetically modified crops under consideration for approval by regulatory agencies; however, there is no consensus in the scientific community on the details of how to perform IgE serum studies. IgE serum studies are an important safety component to acceptance of genetically modified crops when the introduced protein is novel, the introduced protein is similar to known allergens, or the crop is allergenic. In this manuscript, we describe the characteristics of the reagents, validation of assay performance, and data analysis necessary to optimize the information obtained from serum testing of novel proteins and genetically modified (GM) crops and to make results more accurate and comparable between different investigations.
NASA Astrophysics Data System (ADS)
Velychko, T. P.; Soldatkin, O. O.; Melnyk, V. G.; Marchenko, S. V.; Kirdeciler, S. K.; Akata, B.; Soldatkin, A. P.; El'skaya, A. V.; Dzyadevych, S. V.
2016-02-01
Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05-15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis.
1980-06-01
Therefore (-( I=(- 1) :nd the matrices (T-( ) , (T- W))((2 ) are analytic in 0(4). Since v11 (’) = (I-KM ()( ))u (,) and the matrix M W(4) is a nilpotent ...detA-0.4 hv uISi! j :’ h’ 1’’lq- A - matrix , we ohtai n an a priori eIst imaIt, which iSIh h’(11 I; dependence of the ;oluti on on the...2.1 Generalized eigenvectors, spectral pairs and invariant subspaces 9 2.2 Linearization of X- matrix 19 2.3 Spectral theory of linear X-matrices 21
Linking Family Characteristics with Poor Peer Relations: The Mediating Role of Conduct Problems
Bierman, Karen Linn; Smoot, David L.
2012-01-01
Parent, teacher, and peer ratings were collected for 75 grade school boys to test the hypothesis that certain family interaction patterns would be associated with poor peer relations. Path analyses provided support for a mediational model, in which punitive and ineffective discipline was related to child conduct problems in home and school settings which, in turn, predicted poor peer relations. Further analyses suggested that distinct subgroups of boys could be identified who exhibited conduct problems at home only, at school only, in both settings, or in neither setting. Boys who exhibited cross-situational conduct problems were more likely to experience multiple concurrent problems (e.g., in both home and school settings) and were more likely than any other group to experience poor peer relations. However, only about one-third of the boys with poor peer relations in this sample exhibited problem profiles consistent with the proposed model (e.g., experienced high rates of punitive/ineffective home discipline and exhibited conduct problems in home and school settings), suggesting that the proposed model reflects one common (but not exclusive) pathway to poor peer relations. PMID:1865049
Characteristics of Oral Problems and Effects of Oral Care in Terminally Ill Patients With Cancer.
Nakajima, Nobuhisa
2017-06-01
Various distresses appear in the terminal stage of cancer. Oral problems including dry mouth, stomatitis and candidiasis are one of the important problems which should be resolved. The purpose of this study was to investigate oral problems in this stage and improvement of dry mouth by oral care. The study subjects were consecutive terminally ill cancer patients admitted over the past 2 years. Patients were divided based on the status of oral food intake into good oral food intake group (≥30%) and poor oral food intake group. The following 3 items were retrospectively investigated: 1) The incidences of these oral problems, 2) Severity of dry mouth and complication with other oral problems, 3) Improvement of dry mouth using standard oral care by nursing staff and specialist oral care including dentists as needed. There were 115 and 158 patients in good and poor oral intake groups, respectively. 1) The incidences of dry mouth, stomatitis, and candidiasis were significantly higher in poor oral intake group ( p < 0.001). 2) Severe cases of dry mouth (Grade-2&3) were noted in 20.0% and 64.8% in good and poor oral intake groups, respectively ( p < 0.0001). Candidiasis complication rate was significantly higher in poor oral intake group ( p = 0.0002). 3) The rate of dry mouth improvement by oral care was 100% in Grade-1, 86% in Grade-2 and 81% in Grade-3. Oral problems occur in many of terminally ill cancer patients. Accurate diagnosis of oral problems and corresponding appropriate interventions are important for improving quality of end-of-life care.
Gau, Susan Shur-Fen; Chiu, Yen-Nan; Soong, Wei-Tsuen; Lee, Ming-Been
2008-09-01
The literature has documented maternal distress and behavioral problems among children with Down syndrome (DS), however, little is known about paternal adjustment and behavioural problems among the siblings of children with DS. Here, we examined parental psychopathology, parenting style and emotional/behavioral problems among children with DS, their siblings, and controls in Taiwan. We recruited 45 families of children with DS (age, 2-4 years) and 50 families of normally developing children (age, 3-5 years). If there were more than two children in the case family, the sibling whose age was closest to the child with DS was recruited (age, 3-8 years). Both parents completed self-administered measures of their personality characteristics, psychopathology, family functioning, parenting styles, and child behavioral problems, using the Chinese versions of the Maudsley Personality Inventory, Brief Symptom Rating Scale, Family Adaptability and Cohesion Evaluation Scale, Parental Bonding Instrument, and Child Behavioral Checklist, respectively. Children with DS demonstrated significantly more severe symptoms than normal children of a wide range of behavioral problems such as attention problems, delinquency, social problems, somatic complaints, thought problems, and withdrawal compared with the other two groups, and obtained similar parental treatment, except for paternal overprotection. Their parents suffered from more psychopathology and their mothers were less often employed than their counterparts. The siblings of children with DS obtained less overprotection from their mothers than children with DS and less maternal care and control than normal children. There was no difference in emotional/behavioral problems between the siblings and normal controls. Our findings suggest that in addition to the physical, educational and psychological needs of children with DS, the psychological care of their mothers, fathers and siblings also needs to be evaluated. Moreover, parenting
Sasaki, Osamu
2013-06-01
Longevity is an economically important trait of dairy cattle for increasing the profitability of dairy management. The reasons for culling can be either voluntary (primarily productivity) or involuntary (primarily health and fertility). Longevity characteristics include: (i) true longevity (all culling reasons, including productivity); and (ii) functional longevity (all culling reasons, except productivity). Improvements to longevity are made to decrease the rate of involuntary culling rather than extend the herd life (HL). The proportional hazard model is useful for evaluating genetic ability for HL. However, the differences between estimates made using the proportional hazard model and those made using linear single or multiple-trait animal models are not clear. The model commonly used for evaluation differs among countries. Productive traits, udder traits, and feet and legs traits are genetically correlated with longevity, and consequently these traits are used to indirectly evaluate longevity. The reliability of estimates of genetic ability for longevity is increased by combining direct and indirect estimates. In Japan, HL is evaluated using the multiple-traits model. The genetic correlations between HL and other traits vary with the birth year. Therefore, these genetic correlations need to be reviewed regularly.
Extreme Scale Visual Analytics
Wong, Pak C.; Shen, Han-Wei; Pascucci, Valerio
2012-05-08
Extreme-scale visual analytics (VA) is about applying VA to extreme-scale data. The articles in this special issue examine advances related to extreme-scale VA problems, their analytical and computational challenges, and their real-world applications.
ERIC Educational Resources Information Center
Gaudiano, Brandon A.; Brown, Lily A.; Miller, Ivan W.
2012-01-01
Objective: The objective was to learn about the characteristics of psychotherapists who use energy meridian techniques (EMTs). Methods: We conducted an Internet-based survey of the practices and attitudes of licensed psychotherapists. Results: Of 149 survey respondents (21.4% social workers), 42.3% reported that they frequently use or are inclined…
Learning-Method Choices and Personal Characteristics in Solving a Physical Education Problem
ERIC Educational Resources Information Center
Vincent-Morin, Madeleine; Lafont, Lucile
2005-01-01
The goal of this study was to identify the relationships between the learning choices made by pupils and their personal characteristics, including cognitive style (field dependence--independence), a motivational variable (feeling of self-efficacy), and a cognitive variable (task representation). The participants were 64 twelve-year-old sixth…
ERIC Educational Resources Information Center
Barry, Adam E.; Misra, Ranjita; Dennis, Maurice
2006-01-01
Driving a vehicle under the influence of alcohol is a major public health concern. By distinguishing the type of individuals violating driving while intoxicated (DWI) sanctions, intervention programs will be better suited to reduce drinking and driving. The purpose of this study was to examine the personal characteristics of DWI offenders and…
ERIC Educational Resources Information Center
Flessner, Christopher A.; Woods, Douglas W.
2006-01-01
In this study, the authors collected data on the demographic characteristics, phenomenology, and social and economic impact of skin picking. A total of 92 participants completed an anonymous, Internet-based survey through a link to the Trichotillomania Learning Center's home page. Results indicated that skin pickers experienced social,…
ERIC Educational Resources Information Center
Flessner, Christopher A.; Woods, Douglas W.
2006-01-01
In this study, the authors collected data on the demographic characteristics, phenomenology, and social and economic impact of skin picking. A total of 92 participants completed an anonymous, Internet-based survey through a link to the Trichotillomania Learning Center's home page. Results indicated that skin pickers experienced social,…
ERIC Educational Resources Information Center
Gaudiano, Brandon A.; Brown, Lily A.; Miller, Ivan W.
2012-01-01
Objective: The objective was to learn about the characteristics of psychotherapists who use energy meridian techniques (EMTs). Methods: We conducted an Internet-based survey of the practices and attitudes of licensed psychotherapists. Results: Of 149 survey respondents (21.4% social workers), 42.3% reported that they frequently use or are inclined…
ERIC Educational Resources Information Center
Barry, Adam E.; Misra, Ranjita; Dennis, Maurice
2006-01-01
Driving a vehicle under the influence of alcohol is a major public health concern. By distinguishing the type of individuals violating driving while intoxicated (DWI) sanctions, intervention programs will be better suited to reduce drinking and driving. The purpose of this study was to examine the personal characteristics of DWI offenders and…
THE COMPUTATION OF CHARACTERISTIC EXPONENTS IN THE PLANAR RESTRICTED PROBLEM OF THREE BODIES
methods are applied to evaluate the characteristic exponents of Rabe’s Trojan Orbits; they are found to be of the stable type for the ovals, and of...the unstable type for the horse -shoe shaped orbit. When the periodic orbit is symmetric with respect to the axis of syzygies, four independent
ERIC Educational Resources Information Center
Smith-Bonahue, Tina; Larmore, Anne; Harman, Jennifer; Castillo, Melissa
2009-01-01
Children with learning disorders (LD) are at increased risk for a host of psychosocial problems, including Attention Deficit Hyperactivity Disorder (ADHD) (e.g., Bouffard, Roy, & Vezeau, 2005; Elksnin & Elksnin, 2004; Greenham, 1999; Michaels & Lewandowski, 1990; Sideridis, Morgan, Botsas, Padeliadu & Fuchs, 2006; Weiner &…
Maternal Characteristics and Child Problem Behaviors: A Comparison of Foster and Biological Mothers
ERIC Educational Resources Information Center
Lucey, Rose; Fox, Robert A.; Byrnes, Judith B.
2006-01-01
The purpose of this exploratory study was to compare the parenting behavior, stress and support of foster mothers and biological mothers of young children. A sample of 60 mothers of young children (30 foster mothers, 30 biological mothers) completed measures of parenting behavior, parenting stress, child problem behaviors, and perceived social…
Maternal Characteristics and Child Problem Behaviors: A Comparison of Foster and Biological Mothers
ERIC Educational Resources Information Center
Lucey, Rose; Fox, Robert A.; Byrnes, Judith B.
2006-01-01
The purpose of this exploratory study was to compare the parenting behavior, stress and support of foster mothers and biological mothers of young children. A sample of 60 mothers of young children (30 foster mothers, 30 biological mothers) completed measures of parenting behavior, parenting stress, child problem behaviors, and perceived social…
ERIC Educational Resources Information Center
Khan, Anwar; Yusoff, Rosman Bin Md; Isa, Khairunesa Binti
2016-01-01
Scholarly work and research are globally known as stressful and challenging. Teachers may develop different psychological health problems once they are exposed to workplace stressors. Considering it as a serious issue of education sector, this study has examined the linkages between prevalent workplace stressors and psychological health problems…
ERIC Educational Resources Information Center
Smith-Bonahue, Tina; Larmore, Anne; Harman, Jennifer; Castillo, Melissa
2009-01-01
Children with learning disorders (LD) are at increased risk for a host of psychosocial problems, including Attention Deficit Hyperactivity Disorder (ADHD) (e.g., Bouffard, Roy, & Vezeau, 2005; Elksnin & Elksnin, 2004; Greenham, 1999; Michaels & Lewandowski, 1990; Sideridis, Morgan, Botsas, Padeliadu & Fuchs, 2006; Weiner &…
ERIC Educational Resources Information Center
Nitschke, Kai; Ruh, Nina; Kappler, Sonja; Stahl, Christoph; Kaller, Christoph P.
2012-01-01
Understanding the functional neuroanatomy of planning and problem solving may substantially benefit from better insight into the chronology of the cognitive processes involved. Based on the assumption that regularities in cognitive processing are reflected in overtly observable eye-movement patterns, here we recorded eye movements while…
ERIC Educational Resources Information Center
Nitschke, Kai; Ruh, Nina; Kappler, Sonja; Stahl, Christoph; Kaller, Christoph P.
2012-01-01
Understanding the functional neuroanatomy of planning and problem solving may substantially benefit from better insight into the chronology of the cognitive processes involved. Based on the assumption that regularities in cognitive processing are reflected in overtly observable eye-movement patterns, here we recorded eye movements while…
ERIC Educational Resources Information Center
Mergendoller, John R.; Maxwell, Nan L.; Bellisimo, Yolanda
2006-01-01
This study compared the effectiveness of problem-based learning (PBL) and traditional instructional approaches in developing high-school students' macroeconomics knowledge and examined whether PBL was differentially effective with students demonstrating different levels of four aptitudes: verbal ability, interest in economics, preference for group…
Multimedia Analysis plus Visual Analytics = Multimedia Analytics
Chinchor, Nancy; Thomas, James J.; Wong, Pak C.; Christel, Michael; Ribarsky, Martin W.
2010-10-01
Multimedia analysis has focused on images, video, and to some extent audio and has made progress in single channels excluding text. Visual analytics has focused on the user interaction with data during the analytic process plus the fundamental mathematics and has continued to treat text as did its precursor, information visualization. The general problem we address in this tutorial is the combining of multimedia analysis and visual analytics to deal with multimedia information gathered from different sources, with different goals or objectives, and containing all media types and combinations in common usage.
Allen, Brian
2017-04-01
Research examining children with sexual behavior problems (SBP) almost exclusively relies on caregiver reports. The current study, involving a sample of 1112 children drawn from a prospective study, utilizes child self-reports and teacher reports, as well caregiver-reports. First, analyses examined children displaying any SBP; a second set of analyses specifically examined children displaying interpersonal forms of SBP. Caregivers reported greater internalizing, externalizing, and social problems for children with general SBP and/or interpersonal SBP when compared to children without SBP. Caregiver concerns were rarely corroborated by teacher and child reports. Protective services records indicated that SBP was linked to childhood sexual abuse, but sexual abuse occurred in the minority of these cases. Physical abuse was more common among children with interpersonal forms of SBP. The data in the current study suggest the need for multiple reporters when assessing children presenting with SBP and that conventional views of these children may be misleading.
Combining Cauchy and characteristic codes. I. The vacuum cylindrically symmetric problem
NASA Astrophysics Data System (ADS)
Clarke, Chris J.; D'inverno, Ray A.; Vickers, James A.
1995-12-01
This paper is part of a long term program to develop combined Cauchy and characteristic codes as investigative tools in numerical relativity. We set up the necessary machinery for investigating vacuum cylindrical symmetry with two gravitational degrees of freedom. In particular, we demonstrate the need for a decomposition relative to the translational Killing direction using the technique of Geroch in order to obtain regular compactified equations.
NASA Technical Reports Server (NTRS)
Yokota, Jeffrey W.; Huynh, Hung T.
1989-01-01
A new, nonoscillatory upwind scheme is developed for the multidimensional convection equation. The scheme consists of an upwind, nonoscillatory interpolation of data to the surfaces of an intermediate finite volume; a characteristic convection of surface data to a midpoint time level; and a conservative time integration based on the midpoint rule. This procedure results in a convection scheme capable of resolving discontinuities neither aligned with, nor convected along, grid lines.
Dogra, Nisha; Svirydzenka, Nadzeya; Dugard, Pat; Singh, Swaran P; Vostanis, Panos
2013-07-01
Sampling techniques for national surveys have constrained the statistical power in estimating prevalence rates of child mental health problems in minority ethnic groups. To establish the prevalence rates of mental health problems in ethnic Indian adolescents in England and compare these with matched White adolescents living in the same areas. A cross-sectional survey with oversampling of Indian adolescents aged 13-15 years of age. The sample size was 2900 (71% response rate) with 1087 (37%) Indian and 414 (14%) White adolescents. Ethnically Indian adolescents had lower rates of all types of mental health problems (5% v. 13% and 21% v. 30% for abnormal Strengths and Difficulties Questionnaire and Short Mood and Feelings Questionnaire scores, respectively) and substance misuse (18% v. 57%, 5% v.15% and 6% v. 9% for regular alcohol, smoking and drug use, respectively), with the exception of eating disorders, compared with their White counterparts. The odds of an abnormal score on the mental health questionnaires were worse for White compared with Indian children irrespective of sociodemographic variables. Factors relating to how Indian adolescents are parented or their social support networks may be influencing their mental health and may warrant further investigation.
Kim, Hyun-Sil; Kim, Hun-Soo
2005-01-01
The present study aimed to identify the prevalence of incest among Korean adolescents and to determine the family problems, perceived family dynamics, and psychological consequences associated with incest in South Korea. A cross-sectional study was performed, using an anonymous, self-reporting questionnaire. Data were analyzed by percentages, Chi-square, and t-test statistical analyses, using SAS software program. A total of 1,672 adolescents (1,053 student adolescents and 619 delinquent adolescents) were selected using proportional stratified random sampling method in this study. The results showed a 3.7% prevalence of incest in the tested Korean population. Families in which incest occurred were characterized by higher levels of problems, such as psychotic disorders, depression, criminal acts, and alcoholism among family members. Adolescent incest victims showed significantly more dysfunctional and unhealthy in terms of family dynamics and expressed significantly higher maladaptive and problematic psychological patterns than nonvictimized adolescents. The present findings identified some of the family problems and dysfunctional family dynamics may associate with intrafamilial child sexual abuse in Korea. Therefore, when an allegation of intrafamilial sexual abuse is made, health professionals should carry out a comprehensive assessment of their family dynamics and an evaluation of the impact of the abuse on the child and family.
Taylor, Peter J; Wood, Alex M
2013-09-01
Parental appraisals of an adolescent may have an effect upon the adolescent's well-being and likelihood of emotional problems. However, the impact of these parental appraisals is likely to be partly determined by the young person's self-appraisal. It was predicted that a discrepancy in self- and parent appraisals of positive, prosocial qualities would be associated with an increased risk of emotional problems. The study employed a cross-sectional design within a large sample of adolescent and caregiver dyads (N = 3,976, aged 11-17 years), drawn from the 'Mental health of children and young people in Great Britain, 2004' survey. Two separate measures of prosociality were used to ensure that effects were not specific to one measure. The analysis explored the discrepancy in parent and self-ratings on these measures via interactions within a logistic regression framework. Potential confounds, including gender, parental mental health, conduct and hyperkinetic problems were controlled for in the analysis. The logistic regression analyses demonstrated significant interactions between self- and parent ratings of prosocial qualities in predicting the odds of emotional disorder (i.e., depression and anxiety). This effect occurred across both measures of prosocial qualities whilst controlling for confounds. The pattern of the interactions suggested that low parental appraisals had a more detrimental effect on well-being when self-appraisals were highly positive. The results suggest that moderately high self-appraised positive traits may carry a cost of leaving young people more vulnerable to discrepant, negative parental appraisals. This has important implications for the meaning attributed to self-appraised positive traits in clinical contexts. Clinicians should be aware that the association between parental perceptions of a child's prosociality and emotional disorder may be influenced by the adolescents' self-perceptions. Clinicians should therefore endeavour to assess both
Analytical and simulator study of advanced transport
NASA Technical Reports Server (NTRS)
Levison, W. H.; Rickard, W. W.
1982-01-01
An analytic methodology, based on the optimal-control pilot model, was demonstrated for assessing longitidunal-axis handling qualities of transport aircraft in final approach. Calibration of the methodology is largely in terms of closed-loop performance requirements, rather than specific vehicle response characteristics, and is based on a combination of published criteria, pilot preferences, physical limitations, and engineering judgment. Six longitudinal-axis approach configurations were studied covering a range of handling qualities problems, including the presence of flexible aircraft modes. The analytical procedure was used to obtain predictions of Cooper-Harper ratings, a solar quadratic performance index, and rms excursions of important system variables.
Bain, R.J. . Dept. of Geology)
1993-03-01
Fluidized bed combustion of coal is considered one of the more promising clean coal technologies for the future. While much research has gone into the design and operation of FBC units, there is little concern for what characterizes a high quality sorbent and the source of such a sorbent. Carbonate rocks, limestone and dolomite, have been tested extensively as sorbents and primarily two rock characteristics appear to significantly control reactivity: composition and texture. Calcium carbonate is more reactive than magnesium carbonate where all other rock characteristics are the same. In considering texture, highest reactivity is measured for carbonate rocks which consist of homogeneous, euhedral crystals ranging in size from .05 to .2 mm and which possess uniform intercrystalline porosity. The most reactive material possesses both high calcium content, uniform microcrystalline texture and intercrystalline porosity, however, such material is not very abundant in nature and is not locally available to midcontinent facilities. Sucrosic dolomite, which possesses uniform microcrystalline texture and intercrystalline porosity has high rank reactivity. While this rock is quite common, it occurs as beds, generally less than twenty feet thick, interlayered with less reactive dolomite types. Therefore, without selective quarrying methods, production of sorbent with uniformly high reactivity will be impossible.
The Red Herring technique: a methodological response to the problem of demand characteristics.
Laney, Cara; Kaasa, Suzanne O; Morris, Erin K; Berkowitz, Shari R; Bernstein, Daniel M; Loftus, Elizabeth F
2008-07-01
In past research, we planted false memories for food related childhood events using a simple false feedback procedure. Some critics have worried that our findings may be due to demand characteristics. In the present studies, we developed a novel procedure designed to reduce the influence of demand characteristics by providing an alternate magnet for subjects' natural suspicions. We used two separate levels of deception. In addition to giving subjects a typical untrue rationale for the study (i.e., normal deceptive cover story), we built in strong indicators (the "Red Herring") that the study actually had another purpose. Later, we told subjects that we had deceived them, and asked what they believed the "real purpose" of the study was. We also interviewed a subset of subjects in depth in order to analyze their subjective experiences of the procedure and any relevant demand. Our Red Herring successfully tricked subjects, and left little worry that our false memory results were due to demand. This "double cross" technique may have widespread uses in psychological research that hopes to conceal its real hypotheses from experimental subjects.
Zucker, Kenneth J; Bradley, Susan J; Owen-Anderson, Allison; Kibblewhite, Sarah J; Wood, Hayley; Singh, Devita; Choi, Kathryn
2012-01-01
This study provided a descriptive and quantitative comparative analysis of data from an assessment protocol for adolescents referred clinically for gender identity disorder (n = 192; 105 boys, 87 girls) or transvestic fetishism (n = 137, all boys). The protocol included information on demographics, behavior problems, and psychosexual measures. Gender identity disorder and transvestic fetishism youth had high rates of general behavior problems and poor peer relations. On the psychosexual measures, gender identity disorder patients had considerably greater cross-gender behavior and gender dysphoria than did transvestic fetishism youth and other control youth. Male gender identity disorder patients classified as having a nonhomosexual sexual orientation (in relation to birth sex) reported more indicators of transvestic fetishism than did male gender identity disorder patients classified as having a homosexual sexual orientation (in relation to birth sex). The percentage of transvestic fetishism youth and male gender identity disorder patients with a nonhomosexual sexual orientation self-reported similar degrees of behaviors pertaining to transvestic fetishism. Last, male and female gender identity disorder patients with a homosexual sexual orientation had more recalled cross-gender behavior during childhood and more concurrent cross-gender behavior and gender dysphoria than did patients with a nonhomosexual sexual orientation. The authors discuss the clinical utility of their assessment protocol.
Coxell, Adrian; King, Michael; Mezey, Gillian; Gordon, Dawn
1999-01-01
Objective To identify the lifetime prevalence of non-consensual sexual experiences in men, the relationship between such experiences as a child and as an adult, associated psychological and behavioural problems, and help received. Design Cross sectional survey. Setting England. Subjects 2474 men (mean age 46 years) attending one of 18 general practices. Main outcome measures Experiences of non-consensual and consensual sex before and after the age of 16 years—that is, as a child and adult respectively—psychological problems experienced for more than 2 weeks at any one time, use of alcohol (CAGE questionnaire), self harm, and help received. Results 2474 of 3142 men (79%) agreed to participate; 71/2468 (standardised rate 2.89%, 95% confidence interval 2.21% to 3.56%) reported non-consensual sexual experiences as adults, 128/2423 (5.35%, 4.39% to 6.31%) reported non-consensual sexual experiences as children, and 185/2406 (7.66%, 6.54% to 8.77%) reported consensual sexual experiences as children that are illegal under English law. Independent predictors of non-consensual sex as adults were reporting male sexual partners (odds ratio 6.0, 2.6 to 13.5), non-consensual sex in childhood (4.2, 2.1 to 8.6), age (0.98, 0.96 to 0.99), and sex of interviewer (2.0, 1.2 to 3.5). Non-consensual sexual experiences were associated with a greater prevalence of psychological problems, alcohol misuse, and self harm. These sexual experiences were also significant predictors of help received from mental health professionals. Conclusion Almost 3% of men in England report non-consensual sexual experiences as adults. Medical professionals need to be aware of the range of psychological difficulties in men who have had such experiences. They also need to be aware of the relationship between sexual experiences in childhood and adulthood in men. Key messagesAlmost 3% of men report non-consensual sexual experiences as adultsOver 5% of men report sexual abuse as childrenNon-consensual sexual
Devereux, J J; Rydstedt, L W; Cropley, M
2011-09-01
From an original sample of 2454 participants free of self-reported psychological distress, 1463 workers completed a 15-month follow-up. Baseline measures included exposure to job demands, decision latitude, social support and need for recovery. Psychological distress was assessed using the General Health Questionnaire at baseline and at follow-up. The findings showed that medium and high exposure to job demands and social support increased the risk of reporting psychological distress at 15-months (relative risk (RR) = 1.65, 1.45). The highest adjusted RR was observed for workers reporting a high need for recovery after work (RR 2.12, 1.90) and this finding was independent of the effects of job demands, decision latitude and social support. Neither decision latitude, nor low back problems increased the risk of reporting future psychological distress, although neck problems (RR = 1.66) and hand/wrist problems (RR = 1.45) did. It was concluded that need for recovery appears to be an important indicator of individual workers who are at risk of developing psychological distress long term. STATEMENT OF RELEVANCE: This paper reports the findings of a longitudinal study showing that need for recovery from work was the strongest predictor, relative to psychosocial work characteristics (job demands, decision latitude and social support), and musculoskeletal problems, of psychological distress 15 months later in individuals initially free from distress.
NASA Astrophysics Data System (ADS)
Brown-Dymkoski, Eric; Kasimov, Nurlybek; Vasilyev, Oleg V.
2014-04-01
In order to introduce solid obstacles into flows, several different methods are used, including volume penalization methods which prescribe appropriate boundary conditions by applying local forcing to the constitutive equations. One well known method is Brinkman penalization, which models solid obstacles as porous media. While it has been adapted for compressible, incompressible, viscous and inviscid flows, it is limited in the types of boundary conditions that it imposes, as are most volume penalization methods. Typically, approaches are limited to Dirichlet boundary conditions. In this paper, Brinkman penalization is extended for generalized Neumann and Robin boundary conditions by introducing hyperbolic penalization terms with characteristics pointing inward on solid obstacles. This Characteristic-Based Volume Penalization (CBVP) method is a comprehensive approach to conditions on immersed boundaries, providing for homogeneous and inhomogeneous Dirichlet, Neumann, and Robin boundary conditions on hyperbolic and parabolic equations. This CBVP method can be used to impose boundary conditions for both integrated and non-integrated variables in a systematic manner that parallels the prescription of exact boundary conditions. Furthermore, the method does not depend upon a physical model, as with porous media approach for Brinkman penalization, and is therefore flexible for various physical regimes and general evolutionary equations. Here, the method is applied to scalar diffusion and to direct numerical simulation of compressible, viscous flows. With the Navier-Stokes equations, both homogeneous and inhomogeneous Neumann boundary conditions are demonstrated through external flow around an adiabatic and heated cylinder. Theoretical and numerical examination shows that the error from penalized Neumann and Robin boundary conditions can be rigorously controlled through an a priori penalization parameter η. The error on a transient boundary is found to converge as O
Characteristics of gamblers using a national online counselling service for problem gambling.
Rodda, Simone; Lubman, Dan I
2014-06-01
Immediate interventions for a range of health concerns are increasingly being delivered online due to their ease of access and potential to attract new treatment cohorts. This paper describes the development and implementation of a national Australian real time chat and email service for problem gambling. Between September 2009 and September 2011, over 85,000 people visited Gambling Help Online. In addition, 1,722 people engaged in real time chat with trained gambling counsellors, while 299 accessed the email support program. Almost 70 % of people accessing these programs were seeking treatment for the first time, with email contacts significantly more likely to be new treatment seekers (78.0 %) compared with chat clients (68.1 %). Chat clients were more likely to be male than female and aged under 40 years, while email clients, while still highly accessed by young males, were more often female and aged over 40 years. These initial findings suggest that online counselling provides an important alternate mode of service delivery, which is attractive to new treatment seekers. Further research is required to determine the efficacy and impact of this service type on long-term gambling outcomes.
The main characteristics, problems, and prospects for Western European coastal seas.
Dauvin, Jean-Claude
2008-01-01
Located to the far West of Western Europe, France has a western maritime coastal zone of more than 3800 km, which is widely influenced by the North-eastern Atlantic. The English Channel, an epi-continental shallow sea with very strong tides, runs along 650 km of the French coast and 1100 km of the English coast. It is also a bio-geographical crossroad encompassing a much wider range of ecological conditions than other European seas. France's Atlantic coast north of the Gironde estuary is a succession of rocky and sandy shorelines, including a sizeable intertidal zone, a wide continental shelf, and two major estuaries (Loire and Gironde). South of the Gironde, the 260 km of coastline is low, sandy and straight, with a narrowing continental shelf further on South due to the presence of the Cape Breton canyon in the bathyal and abyssal zones. Interface between the continental and oceanic systems, these bordering seas--North Sea, English Channel and Atlantic Ocean--have been the subject of many recent research programmes (the European Mast-FLUXMANCHE and INTERREG programmes; the national coastal environment programme and the LITEAU programme in France), designed to improve comprehension of the functions, production, and dynamics of these seas as well as their future evolution. Given the many conflicting practices in these littoral zones, integrated coastal zone management appears to be essential in order to cope with both natural phenomena, such as the infilling of estuarine zones, cliff erosion, and rising sea levels, and chronic anthropogenic pressures, such as new harbour installations (container dikes, marinas), sea aggregate extraction for human constructions, and offshore wind mill farms. This article provides as complete an overview as possible of the research projects on these bordering seas, both those that have recently been accomplished and those that are currently in progress, in order to highlight the main characteristics of these ecosystems and to
Mgalobelov, Yu. B.; Deineko, A. V.
2011-01-15
A modern approach is proposed for analytical investigation of the stress-strain state, strength, and stability of water-development works. Actual trends in the refinement of analytical investigations are noted: incorporation of parallel-calculation technology, integration of analytical programs and automated design systems, development of structural analyses, etc. A procedure for consideration of the influence exerted by massive production equipment on the stress-strain state of a structure DURING a seismic event is examined.
NASA Astrophysics Data System (ADS)
Milton, Graeme W.
2016-11-01
The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90° rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.
Milton, Graeme W
2016-11-01
The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90(°) rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.
NASA Astrophysics Data System (ADS)
Petrov, D. I.; Petrov, I. B.; Favorskaya, A. V.; Khokhlov, N. I.
2016-06-01
The goal of this paper is the numerical solution of direct problems concerning hydrocarbon seismic exploration on the Arctic shelf. The task is addressed by solving a complete system of linear elasticity equations and a system of acoustic field equations. Both systems are solved by applying the grid-characteristic method, which takes into account all wave processes in a detailed and physically correct manner and produces a solution near the boundaries and interfaces of the integration domain, including the interface between the acoustic and linear elastic media involved. The seismograms and wave patterns obtained by numerically solving these systems are compared. The effect of ice structures on the resulting wave patterns is examined.
NASA Astrophysics Data System (ADS)
Yuan, S.; Xin, C.; Ying, Z.
2016-12-01
In recent years, earthquake disaster occurred frequently in Chinese mainland, the secondary disaster which have been caused by it is more serious in mountainous region. Because of the influence of terrain and geological conditions, the difficulty of earthquake emergency rescue work greatly increased, rescue force is also urged. Yet, it has been studied less on earthquake emergency rescue in mountainous region, the research in existing equipment whether can meet the actual needs of local earthquake emergency rescue is poorly. This paper intends to discuss and solve these problems. Through the mountainous regions Ganzi and Liangshan states in Sichuan field research, we investigated the process of earthquake emergency response and the projects for rescue force after an earthquake, and we also collected and collated local rescue force based data. By consulting experts and statistical analyzing the basic data, there are mainly two problems: The first is about local rescue force, they are poorly equipped and lack in the knowledge of medical help or identify architectural structure. There are no countries to establish a sound financial investment protection mechanism. Also, rescue equipment's updates and maintenance; The second problem is in earthquake emergency rescue progress. In the complicated geologic structure of mountainous regions, traffic and communication may be interrupted by landslides and mud-rock flows after earthquake. The outside rescue force may not arrive in time, rescue equipment was transported by manpower. Because of unknown earthquake disaster information, the local rescue force was deployed unreasonable. From the above, the local government worker should analyze the characteristics of the earthquake disaster in mountainous regions, and research how to improve their earthquake emergency rescue ability. We think they can do that by strengthening and regulating the rescue force structure, enhancing the skills and knowledge, training rescue workers
Solving multiple scattering problems in planetary atmospheres
NASA Technical Reports Server (NTRS)
Irvine, W. M.; Lenoble, J.
1974-01-01
Multiple scattering problems, radiative transfer problems in planetary atmospheres within extended visible portion of the spectrum, are examined. The direct and inverse problems and the extinction coefficient are defined, along with other scattering characteristics. Albedos in semi-infinite and finite atmospheres are considered, as well as surface illumination, energy deposition, and polarization. The Eddington approximation figures prominently in the calculations. Precise numerical methods and analytical solutions are included.
Visual Analytics: How Much Visualization and How Much Analytics?
Keim, Daniel; Mansmann, Florian; Thomas, James J.
2009-12-16
The term Visual Analytics has been around for almost five years by now, but still there are on-going discussions about what it actually is and in particular what is new about it. The core of our view on Visual Analytics is the new enabling and accessible analytic reasoning interactions supported by the combination of automated and visual analytics. In this paper, we outline the scope of Visual Analytics using two problem and three methodological classes in order to work out the need for and purpose of Visual Analytics. Thereby, the respective methods are explained plus examples of analytic reasoning interaction leading to a glimpse into the future of how Visual Analytics methods will enable us to go beyond what is possible when separately using the two methods.
Bustamante, Miguel D; Brachet, Marc
2012-12-01
Numerical simulations of the incompressible Euler equations are performed using the Taylor-Green vortex initial conditions and resolutions up to 4096^{3}. The results are analyzed in terms of the classical analyticity-strip method and Beale, Kato, and Majda (BKM) theorem. A well-resolved acceleration of the time decay of the width of the analyticity strip δ(t) is observed at the highest resolution for 3.7
NASA Astrophysics Data System (ADS)
Bustamante, Miguel D.; Brachet, Marc
2012-12-01
Numerical simulations of the incompressible Euler equations are performed using the Taylor-Green vortex initial conditions and resolutions up to 40963. The results are analyzed in terms of the classical analyticity-strip method and Beale, Kato, and Majda (BKM) theorem. A well-resolved acceleration of the time decay of the width of the analyticity strip δ(t) is observed at the highest resolution for 3.7
NASA Astrophysics Data System (ADS)
Zaki, Wael; Moumni, Ziad
2015-04-01
We propose two frameworks for the derivation of constitutive models for solids undergoing phase transformations. The first is based on the assumption that solid phases within the material are finely mixed whereas the second considers the material as a heterogeneous solution of phase fragments and uses the homogenization theory to derive equilibrium conditions for displacement fields and phase distributions. It is shown that in the case of reversible phase transformation, the energy of the material can be obtained by taking the convex envelope of the energy functions of the constituent phases. As an application, a schematic model is derived for an idealized shape memory alloy and used to obtain a novel analytical solution for the problem of semi-infinite mode III crack in this material. The derivation of the analytical solution uses the hodograph method to map Cartesian coordinates into the hodograph plane. The resulting boundary-value problem for the mode III crack considered becomes analytically tractable for the idealized shape memory alloy considered and leads to closed-form expressions for the displacement and phase volume fraction fields near the crack tip as well as for the boundaries between different phase regions.
NASA Technical Reports Server (NTRS)
Flannelly, W. G.; Fabunmi, J. A.; Nagy, E. J.
1981-01-01
Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described.
Dixon, Robert L.; Boone, John M.
2011-07-15
Purpose: Knowledge of the complete axial dose profile f(z), including its long scatter tails, provides the most complete (and flexible) description of the accumulated dose in CT scanning. The CTDI paradigm (including CTDI{sub vol}) requires shift-invariance along z (identical dose profiles spaced at equal intervals), and is therefore inapplicable to many of the new and complex shift-variant scan protocols, e.g., high dose perfusion studies using variable (or zero) pitch. In this work, a convolution-based beam model developed by Dixon et al.[Med. Phys. 32, 3712-3728, (2005)] updated with a scatter LSF kernel (or DSF) derived from a Monte Carlo simulation by Boone [Med. Phys. 36, 4547-4554 (2009)] is used to create an analytical equation for the axial dose profile f(z) in a cylindrical phantom. Using f(z), equations are derived which provide the analytical description of conventional (axial and helical) dose, demonstrating its physical underpinnings; and likewise for the peak axial dose f(0) appropriate to stationary phantom cone beam CT, (SCBCT). The methodology can also be applied to dose calculations in shift-variant scan protocols. This paper is an extension of our recent work Dixon and Boone [Med. Phys. 37, 2703-2718 (2010)], which dealt only with the properties of the peak dose f(0), its relationship to CTDI, and its appropriateness to SCBCT. Methods: The experimental beam profile data f(z) of Mori et al.[Med. Phys. 32, 1061-1069 (2005)] from a 256 channel prototype cone beam scanner for beam widths (apertures) ranging from a = 28 to 138 mm are used to corroborate the theoretical axial profiles in a 32 cm PMMA body phantom. Results: The theoretical functions f(z) closely-matched the central axis experimental profile data{sup 11} for all apertures (a = 28 -138 mm). Integration of f(z) likewise yields analytical equations for all the (CTDI-based) dosimetric quantities of conventional CT (including CTDI{sub L} itself) in addition to the peak dose f(0) relevant to
NASA Astrophysics Data System (ADS)
Bellouquid, Abdelghani
2015-03-01
The new systems approach in biological sciences proposed in [1] is a constructive reply to the hints of the scientific community [2] and opens new research paths toward developments of new mathematical methods to model the living matter. This comment focuses on some analytic and modeling issues which are somewhat related to my personal scientific knowhow. I look forward to the answer to them as a critical analysis on the topics presented in the following might contribute to research activity in the field and, specifically, to the complex interplay between mathematics and biology. Therefore, after some introductory comment, I pose, for each issue, a specific question.
NASA Technical Reports Server (NTRS)
Degani, Asaf; Mitchell, Christine M.; Chappell, Alan R.; Shafto, Mike (Technical Monitor)
1995-01-01
Task-analytic models structure essential information about operator interaction with complex systems, in this case pilot interaction with the autoflight system. Such models serve two purposes: (1) they allow researchers and practitioners to understand pilots' actions; and (2) they provide a compact, computational representation needed to design 'intelligent' aids, e.g., displays, assistants, and training systems. This paper demonstrates the use of the operator function model to trace the process of mode engagements while a pilot is controlling an aircraft via the, autoflight system. The operator function model is a normative and nondeterministic model of how a well-trained, well-motivated operator manages multiple concurrent activities for effective real-time control. For each function, the model links the pilot's actions with the required information. Using the operator function model, this paper describes several mode engagement scenarios. These scenarios were observed and documented during a field study that focused on mode engagements and mode transitions during normal line operations. Data including time, ATC clearances, altitude, system states, and active modes and sub-modes, engagement of modes, were recorded during sixty-six flights. Using these data, seven prototypical mode engagement scenarios were extracted. One scenario details the decision of the crew to disengage a fully automatic mode in favor of a semi-automatic mode, and the consequences of this action. Another describes a mode error involving updating aircraft speed following the engagement of a speed submode. Other scenarios detail mode confusion at various phases of the flight. This analysis uses the operator function model to identify three aspects of mode engagement: (1) the progress of pilot-aircraft-autoflight system interaction; (2) control/display information required to perform mode management activities; and (3) the potential cause(s) of mode confusion. The goal of this paper is twofold
NASA Technical Reports Server (NTRS)
Degani, Asaf; Mitchell, Christine M.; Chappell, Alan R.; Shafto, Mike (Technical Monitor)
1995-01-01
Task-analytic models structure essential information about operator interaction with complex systems, in this case pilot interaction with the autoflight system. Such models serve two purposes: (1) they allow researchers and practitioners to understand pilots' actions; and (2) they provide a compact, computational representation needed to design 'intelligent' aids, e.g., displays, assistants, and training systems. This paper demonstrates the use of the operator function model to trace the process of mode engagements while a pilot is controlling an aircraft via the, autoflight system. The operator function model is a normative and nondeterministic model of how a well-trained, well-motivated operator manages multiple concurrent activities for effective real-time control. For each function, the model links the pilot's actions with the required information. Using the operator function model, this paper describes several mode engagement scenarios. These scenarios were observed and documented during a field study that focused on mode engagements and mode transitions during normal line operations. Data including time, ATC clearances, altitude, system states, and active modes and sub-modes, engagement of modes, were recorded during sixty-six flights. Using these data, seven prototypical mode engagement scenarios were extracted. One scenario details the decision of the crew to disengage a fully automatic mode in favor of a semi-automatic mode, and the consequences of this action. Another describes a mode error involving updating aircraft speed following the engagement of a speed submode. Other scenarios detail mode confusion at various phases of the flight. This analysis uses the operator function model to identify three aspects of mode engagement: (1) the progress of pilot-aircraft-autoflight system interaction; (2) control/display information required to perform mode management activities; and (3) the potential cause(s) of mode confusion. The goal of this paper is twofold
ERIC Educational Resources Information Center
Crone, Regina M.; Mehta, Smita Shukla
2016-01-01
Setting variables such as location of parent training, programming with common stimuli, generalization of discrete responses to non-trained settings, and subsequent reduction in child problem behavior may influence the effectiveness of interventions. The purpose of this study was to evaluate the effectiveness of home-versus clinic-based training…
ERIC Educational Resources Information Center
Jordan, Michael P.
1980-01-01
This discussion of information structures in written texts describes how linguistic analysis of short published reports leads to the presentation of an algorithm that depicts the problem-solving process in terms of a series of evaluative questions. (Author/CHC)
NASA Astrophysics Data System (ADS)
Popescu, Vasile A.; Puscas, Niculae Tiberiu; Perrone, Guido
2013-10-01
A new fiber optic sensor recently proposed for sensing an analyte with a large refractive index, such as benzene, is investigated using a finite element method in order to optimize its sensitivity. The device exploits the resonant coupling between some modes in a microstructured optical fiber made by a SiO2 rod with several holes, some filled with air, some filled with a liquid analyte, and a central hollow core surrounded by a gold layer and filled with the analyte as well. The structure presents three resonant frequencies, at λ = 0.7105 μm, λ = 2.611 μm and λ = 1.094 μm, depending on the hollow core radius and the different couplings between guided and polariton modes. The first resonant coupling, at λ = 0.7105 μm, is due to a perfect phase matching condition between a mode in the analyte and a supermode; its advantages are a small value of the full width at half maximum (8.6 nm), and a high value of the signal-to-noise ratio (0.29). The second resonant coupling, at λ = 2.611 μm, is due to a loss matching condition between a supermode and a plasmon mode, and its main advantages are large spectral sensitivity and sensor resolution (1.3 × 10-6 RIU). This resonance has also some disadvantages due to a very large value of the full width at half maximum (102 nm for a symmetric line shape), and a small value of the signal-to-noise ratio (0.13). The third resonant coupling is at λ = 1.094 μm and is related again to a phase matching condition between a supermode and a plasmon mode, but for a smaller value of the radius of the central core filled with the analyte. Its advantages are a high value of the amplitude sensitivity (5741.2 RIU-1) and a better value of the sensor resolution (1.74 × 10-6 RIU). The major disadvantages of this structure are a small value of the shift (1.0 nm) towards longer wavelengths of the phase matching point for an increase of the analyte refractive index by 0.001 RIU, a small value of the signal-to-noise ratio (0.03) and a small
NASA Astrophysics Data System (ADS)
Lozhnikov, D. A.
2012-03-01
S. Yu. Dobrokhotov, B. Tirozzi, S. Ya. Sekerzh-Zenkovich, A. I. Shafarevich, and their co-authors suggested new effective asymptotic formulas for solving a Cauchy problem with localized initial data for multidimensional linear hyperbolic equations with variable coefficients and, in particular, for a linearized system of shallow-water equations over an uneven bottom in their cycle of papers. The solutions are localized in a neighborhood of fronts on which focal points and self-intersection points (singular points) occur in the course of time, due to the variability of the coefficients. In the present paper, a numerical realization of asymptotic formulas in a neighborhood of singular points of fronts is presented in the case of the system of shallow-water equations, gluing problems for these formulas together with formulas for regular domains are discussed, and also a comparison of asymptotic solutions with solutions obtained by immediate numerical computations is carried out.
Couturier, Yves
2009-06-01
This communication distinguishes interdisciplinary problems from other neighbouring difficulties, such as difficulties related to work organization. The conceptual proximity between discipline and profession can in fact cause difficulties experienced in the interprofessionnal space to mistakenly incriminate interdisciplinarity. For the analyst, this proximity blurs his insight and, in effect, inhibits the development of adequate solutions to the encountered problem. Hence, this article, based on an ethnographic study of interdisciplinary relations in a small long-term care hospital, aims to alleviate the ambiguity surrounding this issue. In order to do so, this article will begin by recalling the parameters of the theoretical field of interdisciplinarity. Subsequently, the difficulties observed in the long-term care hospital's setting, as they were conceived in the light of interdisciplinarity theory, will be exposed. This article will notably highlight how the nursing staffs contribute to the maintenance of a philosophy of care favourable to the long term deployment of interdisciplinarity.
Brown, Noah A; Weigelin, Helmut C; Bailey, Nathanael; Laliberte, Julie; Elenitoba-Johnson, Kojo S J; Lim, Megan S; Betz, Bryan L
2015-09-01
Detection of high-frequency BRAF V600E mutations in hairy cell leukemia (HCL) has important diagnostic utility. However, the requisite analytic performance for a clinical assay to routinely detect BRAF V600E mutations in HCL has not been clearly defined. In this study, we sought to determine the level of analytic sensitivity needed for formalin-fixed, paraffin-embedded (FFPE) and frozen samples and to compare the performance of 2 allele-specific polymerase chain reaction (PCR) assays. Twenty-nine cases of classic HCL, including 22 FFPE bone marrow aspirates and 7 frozen specimens from blood or bone marrow were evaluated using a laboratory-developed allele-specific PCR assay and a commercially available allele-specific quantitative PCR assay-myT BRAF Ultra. Also included were 6 HCL variant and 40 non-HCL B-cell lymphomas. Two cases of classic HCL, 1 showing CD5 expression, were truly BRAF V600E-negative based on negative results by PCR and sequencing despite high-level leukemic involvement. Among the remaining 27 specimens, V600E mutations were detected in 88.9% (17/20 FFPE; 7/7 frozen) and 81.5% (15/20 FFPE; 7/7 frozen), for the laboratory-developed and commercial assays, respectively. No mutations were detected among the 46 non-HCL lymphomas. Both assays showed an analytic sensitivity of 0.3% involvement in frozen specimens and 5% in FFPE tissue. On the basis of these results, an assay with high analytic sensitivity is required for the clinical detection of V600E mutations in HCL specimens. Two allele-specific PCR assays performed well in both frozen and FFPE bone marrow aspirates, although detection in FFPE tissue required 5% or more involvement.
NASA Astrophysics Data System (ADS)
Newbury*, Dale E.
2005-12-01
Automatic qualitative analysis for peak identification is a standard feature of virtually all modern computer-aided analysis software for energy dispersive X-ray spectrometry with electron excitation. Testing of recently installed systems from four different manufacturers has revealed the occasional occurrence of misidentification of peaks of major constituents whose concentrations exceeded 0.1 mass fraction (10 wt%). Test materials where peak identification failures were observed included ZnS, KBr, FeS2, tantalum-niobium alloy, NIST Standard Reference Material 482 (copper gold alloy), Bi2Te3, uranium rhodium alloys, platinum chromium alloy, GaAs, and GaP. These misidentifications of major constituents were exacerbated when the incident beam energy was 10 keV or lower, which restricted or excluded the excitation of the high photon energy K- and L-shell X-rays where multiple peaks, for example, K[alpha] (K-L2,3) K[beta] (K-M2,3); L[alpha] (L3-M4,5) L[beta] (L2-M4) L[gamma] (L2-N4), are well resolved and amenable to identification with high confidence. These misidentifications are so severe as to properly qualify as blunders that present a serious challenge to the credibility of this critical analytical technique. Systematic testing of a peak identification system with a suite of diverse materials can reveal the specific elements and X-ray peaks where failures are likely to occur.
Plenis, Alina; Oledzka, Ilona; Kowalski, Piotr; Baczek, Tomasz
2016-01-01
During the last few years there has been a growing interest in research focused on the metabolism of steroid hormones despite that the study of metabolic hormone pathways is still a difficult and demanding task because of low steroid concentrations and a complexity of the analysed matrices. Thus, there has been an increasing interest in the development of new, more selective and sensitive methods for monitoring these compounds in biological samples. A lot of bibliographic databases for world research literature were structurally searched using selected review question and inclusion/exclusion criteria. Next, the reports of the highest quality were selected using standard tools (181) and they were described to evaluate the advantages and limitations of different approaches in the measurements of the steroids and their metabolites. The overview of the analytical challenges, development of methods used in the assessment of the metabolic pathways of steroid hormones, and the priorities for future research with a special consideration for liquid chromatography (LC) and capillary electrophoresis (CE) techniques have been presented. Moreover, many LC and CE applications in pharmacological and psychological studies as well as endocrinology and sports medicine, taking into account the recent progress in the area of the metabolic profiling of steroids, have been critically discussed. The latest reports show that LC systems coupled with mass spectrometry have the predominant position in the research of steroid profiles. Moreover, CE techniques are going to gain a prominent position in the diagnosis of hormone levels in the near future.
ERIC Educational Resources Information Center
Akyuz, Halil Ibrahim; Keser, Hafize
2015-01-01
The aim of this study is to investigate the effect of an educational agent, used in online task based learning media, and its form characteristics on problem solving ability perceptions of students. 2x2 factorial design is used in this study. The first study factor is the role of the educational agent and the second factor is form characteristics…
ERIC Educational Resources Information Center
Seiverling, Laura; Hendy, Helen M.; Williams, Keith
2011-01-01
The present study evaluated the 23-item Screening Tool for Feeding Problems (STEP; Matson & Kuhn, 2001) with a sample of children referred to a hospital-based feeding clinic to examine the scale's psychometric characteristics and then demonstrate how a children's revision of the STEP, the STEP-CHILD is associated with child and parent variables.…
ERIC Educational Resources Information Center
Akyuz, Halil Ibrahim; Keser, Hafize
2015-01-01
The aim of this study is to investigate the effect of an educational agent, used in online task based learning media, and its form characteristics on problem solving ability perceptions of students. 2x2 factorial design is used in this study. The first study factor is the role of the educational agent and the second factor is form characteristics…
ERIC Educational Resources Information Center
Seiverling, Laura; Hendy, Helen M.; Williams, Keith
2011-01-01
The present study evaluated the 23-item Screening Tool for Feeding Problems (STEP; Matson & Kuhn, 2001) with a sample of children referred to a hospital-based feeding clinic to examine the scale's psychometric characteristics and then demonstrate how a children's revision of the STEP, the STEP-CHILD is associated with child and parent variables.…
Analytic elements of smooth shapes
NASA Astrophysics Data System (ADS)
Strack, Otto D. L.; Nevison, Patrick R.
2015-10-01
We present a method for producing analytic elements of a smooth shape, obtained using conformal mapping. Applications are presented for a case of impermeable analytic elements as well as for head-specified ones. The mathematical operations necessary to use the elements in practical problems can be carried out before modeling of flow problems begins. A catalog of shapes, along with pre-determined coefficients could be established on the basis of the approach presented here, making applications in the field straight forward.
Guassora, Ann Dorrit; Nielsen, Søren Beck; Reventlow, Susanne
2015-01-01
Objective. The aim of this study is to analyse the interaction between patients and GPs in preventive consultations with an emphasis on how patients answer GPs’ questions about lifestyle, and the conditions these answers impose on the process of establishing agreement about lifestyle as a problem or not. Design. Six general practitioners (GPs) video-recorded 15 annual preventive consultations. From these, 32 excerpts of discussions about lifestyle were analysed using conversation analysis (CA). Results. GPs used an interview format to assess risk in patients’ lifestyles. In some cases patients adhered to this format and answered the GPs’ questions, but in many cases patients gave what we have termed “anticipatory answers”. These answers indicate that the patients anticipate a response from their GPs that would highlight problems with their lifestyle. Typically, in an anticipatory answer, patients bypass the interview format to give their own evaluation of their lifestyle and GPs accept this evaluation. In cases of “no-problem” answers from patients, GPs usually encouraged patients by adding support for current habits. Conclusion. Patients anticipated that GPs might assess their lifestyles as problematic and they incorporated this possibility into their responses. They thereby controlled the definition of their lifestyle as a problem or not. GPs generally did not use the information provided in these answers as a resource for further discussion, but rather relied on standard interview procedures. Staying within the patients’ frame of reference and using the patients’ anticipatory answers might provide GPs with a better point of departure for discussion regarding lifestyle. PMID:26467342
Advances in analytical chemistry
NASA Technical Reports Server (NTRS)
Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.
1991-01-01
Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.
Advances in analytical chemistry
NASA Technical Reports Server (NTRS)
Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.
1991-01-01
Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.
Lewis, D.W. . Dept. of Geology); McConchie, D.M. . Centre for Coastal Management)
1994-01-01
Both a self instruction manual and a cookbook'' guide to field and laboratory analytical procedures, this book provides an essential reference for non-specialists. With a minimum of mathematics and virtually no theory, it introduces practitioners to easy, inexpensive options for sample collection and preparation, data acquisition, analytic protocols, result interpretation and verification techniques. This step-by-step guide considers the advantages and limitations of different procedures, discusses safety and troubleshooting, and explains support skills like mapping, photography and report writing. It also offers managers, off-site engineers and others using sediments data a quick course in commissioning studies and making the most of the reports. This manual will answer the growing needs of practitioners in the field, either alone or accompanied by Practical Sedimentology, which surveys the science of sedimentology and provides a basic overview of the principles behind the applications.
Techniques of Problem Solving.
ERIC Educational Resources Information Center
Krantz, Steven G.
The purpose of this book is to teach the basic principles of problem solving in both mathematical and non-mathematical problems. The major components of the book consist of learning to translate verbal discussion into analytical data, learning problem solving methods for attacking collections of analytical questions or data, and building a…
Techniques of Problem Solving.
ERIC Educational Resources Information Center
Krantz, Steven G.
The purpose of this book is to teach the basic principles of problem solving in both mathematical and non-mathematical problems. The major components of the book consist of learning to translate verbal discussion into analytical data, learning problem solving methods for attacking collections of analytical questions or data, and building a…
ERIC Educational Resources Information Center
Kelly, William E.
2005-01-01
This study explored the relationship between night-sky watching and self-reported cognitive variables: need for cognition and social problem-solving. University students (N = 140) completed the Noctcaelador Inventory, the Need for Cognition Scale, and the Social Problem Solving Inventory. The results indicated that an interest in the night-sky was…
ERIC Educational Resources Information Center
Kelly, William E.
2005-01-01
This study explored the relationship between night-sky watching and self-reported cognitive variables: need for cognition and social problem-solving. University students (N = 140) completed the Noctcaelador Inventory, the Need for Cognition Scale, and the Social Problem Solving Inventory. The results indicated that an interest in the night-sky was…
ERIC Educational Resources Information Center
Liljequist, Laura; Renk, Kimberly
2007-01-01
This study examined the relationships among teachers' perceptions of students' behavioural problems and their own efficacy and psychological symptoms. Findings suggested that teachers were more bothered by externalising (i.e., acting out) than internalising (i.e., withdrawal, depression) behavioural problems in their students, and believed that…
van Gent, Tiejo; Goedhart, Arnold W; Treffers, Philip D A
2011-06-01
High rates of psychopathology were found amongst deaf adolescents, but little is known about the psychosocial risk factors. This study investigated whether (1) less severe deafness and/or acquired or otherwise complicated deafness, and (2) having mainly contacts with hearing people, each represent chronic stressful conditions that moderate the associations between self-esteem and emotional problems. In addition, the moderating effect of observed peer rejection on the association between social acceptance and behavioural problems was explored. Deaf adolescents of normal intelligence (N = 68) completed the Self Perception Profile for Adolescents. Psychopathology was assessed using a semi-structured interview with adolescents and reports by parents, teachers and expert ratings. Data on moderator variables were collected from school records, parental and teachers' reports. Emotional mental health problems were negatively associated with self-esteem and positively with peer rejection. The association between self-esteem and emotional problems was moderated by the deafness variable less severe deafness or acquired or otherwise complicated deafness. Behavioural mental health problems were positively associated with social acceptance and peer rejection but negatively with the amount of involvement with hearing people. Peer rejection moderated the association between social acceptance and behavioural problems. The findings emphasise the importance of considering self-concept dimensions, peer problems and deafness- and context-related characteristics when assessing and treating deaf adolescents. © 2011 The Authors. Journal of Child Psychology and Psychiatry © 2011 Association for Child and Adolescent Mental Health.
Araujo, G.L.; Castano, J.; Luque, A.; Sanchez, E.
1983-12-01
The current-voltage characteristics of p/sup +/-i-n/sup +/ solar cells is analyzed and an approximated two-exponential model for the dark and J /SUB sc/ -V /SUB oc/ operation is presented. It is shown that this two-exponential model and the superposition principle can be used as a first approximation and as a means of attaining further insight on the basic mechanisms actually occurring in the cell. However, some care should be taken when trying to determine the physical solar cell parameters from experimental data through fitting techniques. All this facts are illustrated and confirmed with theoretical examples and measured currentvoltage characteristics of six different devices.
NASA Technical Reports Server (NTRS)
Tarnopolskiy, V. I.
1978-01-01
Widely used remote probing methods, and especially the multispectral method, for studying the earth from aerospace platforms necessitate the systematization and accumulation of data on the relationships between remote observations and measured parameters and characteristic properties and conditions of phenomena on the earth's surface. Data were presented on the optical characteristics of natural objects which arise during observations of these objects over a wide spectral interval which encompasses solar radiation reflected by the object as well as the object's inherent thermal radiation. The influence of the earth's atmosphere on remote measurements and several problems in simulation and calculation are discussed.
ERIC Educational Resources Information Center
Novak, Elena
2012-01-01
The study explored instructional benefits of a storyline gaming characteristic (GC) on learning effectiveness, efficiency, and engagement with the use of an online instructional simulation for graduate students in an introductory statistics course. In addition, the study focused on examining the effects of a storyline GC on specific learning…
Gao, Fei; Xu, Lingzhi; Zhang, Yuejing; Yang, Zengling; Han, Lujia; Liu, Xian
2018-02-01
The objectives of the current study were to explore the correlation between Raman spectroscopy and lipid characteristics and to assess the potential of Raman spectroscopic methods for distinguishing the different sources of animal-originated feed based on lipid characteristics. A total of 105 lipid samples derived from five animal species have been analyzed by gas chromatography (GC) and FT-Raman spectroscopy. High correlations (r(2)>0.94) were found between the characteristic peak ratio of the Raman spectra (1654/1748 and 1654/1445) and the degree of unsaturation of the animal lipids. The results of FT-Raman data combined with chemometrics showed that the fishmeal, poultry, porcine and ruminant (bovine and ovine) MBMs could be well separated based on their lipid spectral characteristics. This study demonstrated that FT-Raman spectroscopy can mostly exhibit the lipid structure specificity of different species of animal-originated feed and can be used to discriminate different animal-originated feed samples. Copyright © 2017. Published by Elsevier Ltd.
ERIC Educational Resources Information Center
Novak, Elena
2012-01-01
The study explored instructional benefits of a storyline gaming characteristic (GC) on learning effectiveness, efficiency, and engagement with the use of an online instructional simulation for graduate students in an introductory statistics course. In addition, the study focused on examining the effects of a storyline GC on specific learning…
Smarius, Laetitia Joanna Clara Antonia; Strieder, Thea G A; Loomans, Eva M; Doreleijers, Theo A H; Vrijkotte, Tanja G M; Gemke, Reinoud J; van Eijsden, Manon
2017-03-01
The onset of behavioral problems starts in early life. This study examined whether excessive infant crying (maternal ratings) is a determinant of emotional and behavioral problems at age 5-6 years. In the Amsterdam Born Children and their Development (ABCD) study, a large prospective, observational, population-based multiethnic birth cohort, excessive infant crying (crying for three or more hours per 24 h day over the past week) during the 13th week after birth (range 11-25 weeks, SD 2 weeks), maternal burden of infant care and maternal aggressive behavior (either angry speaking, or physical aggression) was assessed using a questionnaire. Children's behavioral and emotional problems at the age of 5-6 were assessed by Goodman's Strengths and Difficulties Questionnaire (SDQ), by the subscale of generalized anxiety of the preschool anxiety scale (PAS), and by the Short Mood and Feelings Questionnaire (SMFQ). Inclusion criterion was singleton birth. Exclusion criteria were preterm born babies or congenital disorders. Among 3389 children, excessive infant crying (n = 102) was associated with a twofold increased risk of the overall problem behavior, conduct problems, hyperactivity, and mood problems at the age of 5-6 [ORs between 1.75 (95 % CI 1.09-2.81) and 2.12 (95 % CI 1.30-3.46)]. This association was mediated by maternal burden of infant care (change in odds' ratio 1-17 %) and maternal aggressive behavior (change in odds' ratio 4-10 %). There was no effect modification by the child's gender or maternal parity. Excessive infant crying was not associated with general anxiety problems. Excessive infant crying doubles the risk of behavioral, hyperactivity, and mood problems at the age of 5-6, as reported by their mother. Maternal burden of infant care partially mediates the association between excessive crying and behavioral and mood problems. Special care for mothers with a high burden of care for their excessive crying infant, notwithstanding their own good
Ledgerwood, David M; Milosevic, Aleks
2015-06-01
Problem and pathological gamblers (PPGs) are more likely than the general population to experience co-occurring psychiatric problems. However, the problem gambling literature has largely overlooked the importance of trauma and post-traumatic stress disorder (PTSD) as a prevalent co-occurring condition among PPGs. This study examined clinical differences between PPGs with and without a history of co-occurring PTSD. Lifetime PPGs (N = 150) recruited from community sources completed clinical assessments including measures of problem gambling severity, co-occurring psychiatric conditions, gambling motivations and personality traits. Over 19% of the participants met criteria for a lifetime diagnosis of PTSD. Those presenting with PTSD histories were more likely to be women, and were more likely to have lifetime substance use disorder (abuse and/or dependence) and substance dependence, lifetime major depressive disorder, current dysthymic disorder, and lifetime and current anxiety disorder. Those with lifetime PTSD also were more likely to use gambling as a way to cope with negative emotions and experienced greater negative emotionality. Few PPGs (16%) had ever sought treatment for their gambling problems. PTSD is a prevalent condition among individuals with lifetime PPG recruited from the community, and is associated with greater psychiatric co-morbidity among these populations. More research is needed to further understand the relationship between gambling and trauma, and better outreach is needed to encourage these individuals to seek treatment.
Cooley, Richard L.
1992-01-01
MODFE, a modular finite-element model for simulating steady- or unsteady-state, area1 or axisymmetric flow of ground water in a heterogeneous anisotropic aquifer is documented in a three-part series of reports. In this report, part 2, the finite-element equations are derived by minimizing a functional of the difference between the true and approximate hydraulic head, which produces equations that are equivalent to those obtained by either classical variational or Galerkin techniques. Spatial finite elements are triangular with linear basis functions, and temporal finite elements are one dimensional with linear basis functions. Physical processes that can be represented by the model include (1) confined flow, unconfined flow (using the Dupuit approximation), or a combination of both; (2) leakage through either rigid or elastic confining units; (3) specified recharge or discharge at points, along lines, or areally; (4) flow across specified-flow, specified-head, or head-dependent boundaries; (5) decrease of aquifer thickness to zero under extreme water-table decline and increase of aquifer thickness from zero as the water table rises; and (6) head-dependent fluxes from springs, drainage wells, leakage across riverbeds or confining units combined with aquifer dewatering, and evapotranspiration. The matrix equations produced by the finite-element method are solved by the direct symmetric-Doolittle method or the iterative modified incomplete-Cholesky conjugate-gradient method. The direct method can be efficient for small- to medium-sized problems (less than about 500 nodes), and the iterative method is generally more efficient for larger-sized problems. Comparison of finite-element solutions with analytical solutions for five example problems demonstrates that the finite-element model can yield accurate solutions to ground-water flow problems.
NASA Astrophysics Data System (ADS)
Seo, In-jin; Choi, Won; Seong, Jae-gyu; Lee, Bang-wook; Koo, Ja-yoon
2014-08-01
It has been reported that the insulation design under DC stress is considered as one of the critical factors in determining the performance of high-voltage direct current (HVDC) superconducting cable. Therefore, it is fundamentally necessary to investigate the DC breakdown characteristics of the composite insulation system consisting of liquid nitrogen (LN2)/polypropylene-laminated-paper (PPLP). In particular, the insulation characteristics under DC polarity reversal condition should be verified to understand the polarity effect of the DC voltage considering the unexpected incidents taking place at line-commutated-converters (LCC) under service at a DC power grid. In this study, to examine the variation of DC electric field strength, the step voltage and polarity reversal breakdown tests are performed under DC stress. Also, we investigate the electric field distributions in a butt gap of the LN2/PPLP condition considering the DC polarity reversal by using simulation software.
Challenges for Visual Analytics
Thomas, James J.; Kielman, Joseph
2009-09-23
Visual analytics has seen unprecedented growth in its first five years of mainstream existence. Great progress has been made in a short time, yet great challenges must be met in the next decade to provide new technologies that will be widely accepted by societies throughout the world. This paper sets the stage for some of those challenges in an effort to provide the stimulus for the research, both basic and applied, to address and exceed the envisioned potential for visual analytics technologies. We start with a brief summary of the initial challenges, followed by a discussion of the initial driving domains and applications, as well as additional applications and domains that have been a part of recent rapid expansion of visual analytics usage. We look at the common characteristics of several tools illustrating emerging visual analytics technologies, and conclude with the top ten challenges for the field of study. We encourage feedback and collaborative participation by members of the research community, the wide array of user communities, and private industry.
ERIC Educational Resources Information Center
Munoz-Martinez, Amanda; Novoa-Gomez, Monica; Gutierrez, Rochy Vargas
2012-01-01
Functional Analytic Psychotherapy (FAP) has been making an important rise in Ibero-America in recent years. This paper presents a review of different contributions, problems and some proposals. Three principal topics are reviewed: (a) general characteristics and theoretical bases of FAP, (b) the uses of FAP and its relationship with other…
Florin, Cécile; Garraud, Olivier; Molliex, Serge; Tardy, Brigitte; Campos, Lydia; Scherrer, Carine
2016-06-01
The Innovance VWF:Ac test (Siemens) has the particularity to assess the binding capacity of von Willebrand factor (VWF) to recombinant platelet GPIb mutated in the absence of ristocetin. Our study aimed to evaluate and validate according to standard NF EN ISO 15189 the original protocol adaptation on STA-R Evolution series analyser (Diagnostica Stago). We evaluated the performance in terms of imprecision and we validate additional parameters necessary in range B as recommended by the SH GTA 04 (Cofrac). We compared the new assay with the reference assay: ristocetin cofactor activity (VWF:RCo) performed on the BCS-XP analyser by testing retrospectively samples from 82 healthy normal subjects and 61 patients with von Willebrand disease (VWD). This new assay is consistent with objectives set in terms of imprecision with CV around 4%. Excepted limit of quantification higher, additional parameters evaluated in range B have been validated. The Innovance VWF: Ac assay allowed the detection of all deficits of VWF already detected by the VWF:RCo test on the BCS-XP. This adjustment on STA-R analyser therefore has satisfactory analytical performance criteria. Apart from the limit of quantification, this reagent can be used according to the recommendations specified in the original protocol adaptation. Its performance and compatibility with the spot measurement allow the diagnosis and therapeutic monitoring of VWD according to current requirements and guidelines.
ERIC Educational Resources Information Center
Fischer, Benedikt; Dawe, Meghan; Mcguire, Fraser; Shuper, Paul A; Jones, Wayne; Rudzinski, Katherine; Rehm, Jurgen
2012-01-01
Aims: Assess key cannabis use, risk and outcome characteristics among high-frequency cannabis users within a university student sample in Toronto, Canada. Methods: N = 134 active universities students (ages of 18-28) using cannabis at least three times per week were recruited by mass advertisement, telephone-screened and anonymously assessed by an…
Ryan E Emanuel; John J Buckley; Peter V Caldwell; Steve McNulty; Ge Sun
2015-01-01
Interbasin water transfers are globally important water management strategies, yet little is known about their role in the hydrologic cycle at regional and continental scales. Specifically, there is a dearth of centralized information on transfer locations and characteristics, and few analyses place transfers into a relevant hydrological context. We assessed...
ERIC Educational Resources Information Center
Barry, Tammy D.; Lochman, John E.; Fite, Paula J.; Wells, Karen C.; Colder, Craig R.
2012-01-01
The current study utilized a longitudinal design to examine the effects of neighborhood and parenting on 120 at-risk children's academic and aggressive outcomes, concurrently and at two later timepoints during the transition to middle school. Random effects regression models were estimated to examine whether neighborhood characteristics and harsh…
ERIC Educational Resources Information Center
Barry, Tammy D.; Lochman, John E.; Fite, Paula J.; Wells, Karen C.; Colder, Craig R.
2012-01-01
The current study utilized a longitudinal design to examine the effects of neighborhood and parenting on 120 at-risk children's academic and aggressive outcomes, concurrently and at two later timepoints during the transition to middle school. Random effects regression models were estimated to examine whether neighborhood characteristics and harsh…
ERIC Educational Resources Information Center
Fischer, Benedikt; Dawe, Meghan; Mcguire, Fraser; Shuper, Paul A; Jones, Wayne; Rudzinski, Katherine; Rehm, Jurgen
2012-01-01
Aims: Assess key cannabis use, risk and outcome characteristics among high-frequency cannabis users within a university student sample in Toronto, Canada. Methods: N = 134 active universities students (ages of 18-28) using cannabis at least three times per week were recruited by mass advertisement, telephone-screened and anonymously assessed by an…
ERIC Educational Resources Information Center
Young, Martin; Stevens, Matthew
2009-01-01
To explore the structure of gambling participation and its association with problem gambling, we draw upon Caillois's distinction between games based on competition (i.e. "agon") and those based on chance (i.e. "alea"). The idea that "alea" and "agon" are socially patterned and associated with differing…
ERIC Educational Resources Information Center
Young, Martin; Stevens, Matthew
2009-01-01
To explore the structure of gambling participation and its association with problem gambling, we draw upon Caillois's distinction between games based on competition (i.e. "agon") and those based on chance (i.e. "alea"). The idea that "alea" and "agon" are socially patterned and associated with differing…
ERIC Educational Resources Information Center
Sen, Bisakha
2010-01-01
Objective: To examine the association between frequency of family dinners (FFD) and selected problem behaviors for adolescents after adjusting for family connectedness, parental awareness, other family activities, and other potentially confounding factors. Methods: Data are drawn from the National Longitudinal Survey of Youth, 1997. The primary…
ERIC Educational Resources Information Center
de Koning, Bjorn B.; Loyens, Sofie M. M.; Rikers, Remy M. J. P.; Smeets, Guus; van der Molen, Henk T.
2012-01-01
This study investigated the simultaneous impact of demographic, personality, intelligence, and (prior) study performance factors on students' academic achievement in a three-year academic problem-based psychology program. Information regarding students' gender, age, nationality, pre-university education, high school grades, Big Five personality…
ERIC Educational Resources Information Center
Sen, Bisakha
2010-01-01
Objective: To examine the association between frequency of family dinners (FFD) and selected problem behaviors for adolescents after adjusting for family connectedness, parental awareness, other family activities, and other potentially confounding factors. Methods: Data are drawn from the National Longitudinal Survey of Youth, 1997. The primary…
ERIC Educational Resources Information Center
de Koning, Bjorn B.; Loyens, Sofie M. M.; Rikers, Remy M. J. P.; Smeets, Guus; van der Molen, Henk T.
2012-01-01
This study investigated the simultaneous impact of demographic, personality, intelligence, and (prior) study performance factors on students' academic achievement in a three-year academic problem-based psychology program. Information regarding students' gender, age, nationality, pre-university education, high school grades, Big Five personality…
Collaborative Visual Analytics: A Health Analytics Approach to Injury Prevention
Fisher, Brian; Smith, Jennifer; Pike, Ian
2017-01-01
Background: Accurate understanding of complex health data is critical in order to deal with wicked health problems and make timely decisions. Wicked problems refer to ill-structured and dynamic problems that combine multidimensional elements, which often preclude the conventional problem solving approach. This pilot study introduces visual analytics (VA) methods to multi-stakeholder decision-making sessions about child injury prevention; Methods: Inspired by the Delphi method, we introduced a novel methodology—group analytics (GA). GA was pilot-tested to evaluate the impact of collaborative visual analytics on facilitating problem solving and supporting decision-making. We conducted two GA sessions. Collected data included stakeholders’ observations, audio and video recordings, questionnaires, and follow up interviews. The GA sessions were analyzed using the Joint Activity Theory protocol analysis methods; Results: The GA methodology triggered the emergence of ‘common ground’ among stakeholders. This common ground evolved throughout the sessions to enhance stakeholders’ verbal and non-verbal communication, as well as coordination of joint activities and ultimately collaboration on problem solving and decision-making; Conclusions: Understanding complex health data is necessary for informed decisions. Equally important, in this case, is the use of the group analytics methodology to achieve ‘common ground’ among diverse stakeholders about health data and their implications. PMID:28895928
Collaborative Visual Analytics: A Health Analytics Approach to Injury Prevention.
Al-Hajj, Samar; Fisher, Brian; Smith, Jennifer; Pike, Ian
2017-09-12
Background: Accurate understanding of complex health data is critical in order to deal with wicked health problems and make timely decisions. Wicked problems refer to ill-structured and dynamic problems that combine multidimensional elements, which often preclude the conventional problem solving approach. This pilot study introduces visual analytics (VA) methods to multi-stakeholder decision-making sessions about child injury prevention; Methods: Inspired by the Delphi method, we introduced a novel methodology-group analytics (GA). GA was pilot-tested to evaluate the impact of collaborative visual analytics on facilitating problem solving and supporting decision-making. We conducted two GA sessions. Collected data included stakeholders' observations, audio and video recordings, questionnaires, and follow up interviews. The GA sessions were analyzed using the Joint Activity Theory protocol analysis methods; Results: The GA methodology triggered the emergence of 'common ground' among stakeholders. This common ground evolved throughout the sessions to enhance stakeholders' verbal and non-verbal communication, as well as coordination of joint activities and ultimately collaboration on problem solving and decision-making; Conclusions: Understanding complex health data is necessary for informed decisions. Equally important, in this case, is the use of the group analytics methodology to achieve 'common ground' among diverse stakeholders about health data and their implications.
Danner, Marion; Vennedey, Vera; Hiligsmann, Mickaël; Fauser, Sascha; Gross, Christian; Stock, Stephanie
2017-09-01
In this study, we conducted an analytic hierarchy process (AHP) and a discrete choice experiment (DCE) to elicit the preferences of patients with age-related macular degeneration using identical attributes and levels. To compare preference-based weights for age-related macular degeneration treatment attributes and levels generated by two elicitation methods. The properties of both methods were assessed, including ease of instrument use. A DCE and an AHP experiment were designed on the basis of five attributes. Preference-based weights were generated using the matrix multiplication method for attributes and levels in AHP and a mixed multinomial logit model for levels in the DCE. Attribute importance was further compared using coefficient (DCE) and weight (AHP) level ranges. The questionnaire difficulty was rated on a qualitative scale. Patients were asked to think aloud while providing their judgments. AHP and DCE generated similar results regarding levels, stressing a preference for visual improvement, frequent monitoring, on-demand and less frequent injection schemes, approved drugs, and mild side effects. Attribute weights derived on the basis of level ranges led to a ranking that was opposite to the AHP directly calculated attribute weights. For example, visual function ranked first in the AHP and last on the basis of level ranges. The results across the methods were similar, with one exception: the directly measured AHP attribute weights were different from the level-based interpretation of attribute importance in both DCE and AHP. The dependence/independence of attribute importance on level ranges in DCE and AHP, respectively, should be taken into account when choosing a method to support decision making. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
Sen, Bisakha
2010-02-01
To examine the association between frequency of family dinners (FFD) and selected problem behaviors for adolescents after adjusting for family connectedness, parental awareness, other family activities, and other potentially confounding factors. Data are drawn from the National Longitudinal Survey of Youth, 1997. The primary variable of interest is self-reported FFD in a typical week. Problem behaviors studied are substance-use, physical violence, property-destruction, stealing, running away from home, andgang membership. Multivariate logistic models are estimated for each behaviors. Linear regression models are estimated for behavior-frequency for the sub-samples engaging in them. Analysis is done separately by gender. FFD is negatively associated with substance-use and running away for females; drinking, physical violence, property-destruction, stealing and running away for males. Family meals are negatively associated to certain problem behaviors for adolescents even after controlling rigorously for potentially confounding factors. Thus, programs that promote family meals are beneficial. Copyright (c) 2009 The Association for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.
Cohen-Kettenis, Peggy T; Owen, Allison; Kaijser, Vanessa G; Bradley, Susan J; Zucker, Kenneth J
2003-02-01
This study examined demographic characteristics, social competence, and behavior problems in clinic-referred children with gender identity problems in Toronto, Canada (N = 358), and Utrecht, The Netherlands (N = 130). The Toronto sample was, on average, about a year younger than the Utrecht sample at referral, had a higher percentage of boys, had a higher mean IQ, and was less likely to be living with both parents. On the Child Behavior Checklist (CBCL), both groups showed, on average, clinical range scores in both social competence and behavior problems. A CBCL-derived measure of poor peer relations showed that boys in both clinics had worse ratings than did the girls. A multiple regression analysis showed that poor peer relations were the strongest predictor of behavior problems in both samples. This study-the first cross-national, cross-clinic comparative analysis of children with gender identity disorder-found far more similarities than differences in both social competence and behavior problems. The most salient demographic difference was age at referral. Cross-national differences in factors that might influence referral patterns are discussed.
[Analytical problems of altered states of consciousness].
Frolov, M V
1993-01-01
Modified states of consciousness are created under the conditions of monotony with modulating influences in minute wave length diapason. These data point to an important role of the modulating system of the cerebral brain in consciousness the content of which is determined by informational processes.
Parallel Aircraft Trajectory Optimization with Analytic Derivatives
NASA Technical Reports Server (NTRS)
Falck, Robert D.; Gray, Justin S.; Naylor, Bret
2016-01-01
Trajectory optimization is an integral component for the design of aerospace vehicles, but emerging aircraft technologies have introduced new demands on trajectory analysis that current tools are not well suited to address. Designing aircraft with technologies such as hybrid electric propulsion and morphing wings requires consideration of the operational behavior as well as the physical design characteristics of the aircraft. The addition of operational variables can dramatically increase the number of design variables which motivates the use of gradient based optimization with analytic derivatives to solve the larger optimization problems. In this work we develop an aircraft trajectory analysis tool using a Legendre-Gauss-Lobatto based collocation scheme, providing analytic derivatives via the OpenMDAO multidisciplinary optimization framework. This collocation method uses an implicit time integration scheme that provides a high degree of sparsity and thus several potential options for parallelization. The performance of the new implementation was investigated via a series of single and multi-trajectory optimizations using a combination of parallel computing and constraint aggregation. The computational performance results show that in order to take full advantage of the sparsity in the problem it is vital to parallelize both the non-linear analysis evaluations and the derivative computations themselves. The constraint aggregation results showed a significant numerical challenge due to difficulty in achieving tight convergence tolerances. Overall, the results demonstrate the value of applying analytic derivatives to trajectory optimization problems and lay the foundation for future application of this collocation based method to the design of aircraft with where operational scheduling of technologies is key to achieving good performance.
NASA Astrophysics Data System (ADS)
Emanuel, Ryan E.; Buckley, John J.; Caldwell, Peter V.; McNulty, Steven G.; Sun, Ge
2015-12-01
Interbasin water transfers are globally important water management strategies, yet little is known about their role in the hydrologic cycle at regional and continental scales. Specifically, there is a dearth of centralized information on transfer locations and characteristics, and few analyses place transfers into a relevant hydrological context. We assessed hydrological characteristics of interbasin transfers (IBTs) in the conterminous US using a nationwide inventory of transfers together with historical climate data and hydrological modeling. Supplying and receiving drainage basins share similar hydroclimatological conditions, suggesting that climatological drivers of water shortages in receiving basins likely have similar effects on supplying basins. This result calls into question the effectiveness of transfers as a strategy to mitigate climate-driven water shortages, as the water shortage may be displaced but not resolved. We also identified hydrologically advantageous and disadvantageous IBTs by comparing the water balances of supplying and receiving basins. Transfer magnitudes did not vary between the two categories, confirming that factors driving individual IBTs, such as patterns of human water demand or engineering constraints, also influence the continental-scale distribution of transfers. Some IBTs impact streamflow for hundreds of kilometers downstream. Transfer magnitude, hydroclimate and organization of downstream river networks mediate downstream impacts, and these impacts have the potential to expand downstream nonlinearly during years of drought. This work sheds new light on IBTs and emphasizes the need for updated inventories and analyses that place IBTs in an appropriate hydrological context.
Khanbhai, Yasmin; Smith, David; Battersby, Malcolm
2017-03-01
Problem gambling is a growing public health concern and treatment incompletion levels remain high. The study aims to support and extend previous studies in relation to the heterogeneity of the gambling population based on gender and gambling type, and the implications of subgroup differences on treatment outcomes. Additionally, the concept of drop-out is addressed in terms of categorical treatment measures. The empirical findings are examined in the context of the theoretical framework of the pathways model. Participants were recruited from the Statewide Gambling Therapy Service and stratified into subgroups based on gender and gambling mode preference [Electronic Gambling Machines (EGM) or track race betters]. Baseline predictors collected and analysed using multinomial logistical regression included demographic information as well as gambling variables, while treatment outcomes consisted of three therapist rated measures. Significant differences between the subgroups were found for age, marital and employment status, gambling duration, alcohol use and the Kessler 10 measure of psychological distress. Specifically, male track race gamblers were younger, married, employed, had a longer duration of gambling, higher alcohol use and lower psychological distress relative to EGM users. No difference was found in any of the treatment outcomes, however, consistent with previous studies, all subgroups had high treatment incompletion levels. The findings demonstrate the importance of screening, assessing and treating problem gamblers as a heterogeneous group with different underlying demographics and psychopathologies. It is also hoped future studies will continue to address treatment incompletion with a re-conceptualisation of the term drop-out.
Bashammakh, A S; Bahaffi, S O; Al-Shareef, F M; El-Shahawi, M S
2009-03-01
The kinetic parameters of gold(III) sorption by unloaded polyurethane foams (PUFs) and PUFs impregnated with some onium cations e.g. tetramethylammonium perchlorate (TMA(+)ClO(4)(-)), tetrabutylammonium iodide (TBA(+)I(-)), and tetraheptylammonium bromide (THA(+)Br(-)), have been determined. The retention steps were found to be fast, reached equilibrium in a few minutes and followed a first-order rate equation with an overall rate constant, k, of 0.0076 and 0.007 min(-1), respectively. The thermodynamic characteristics of gold(III) retention by the unloaded PUFs and THA(+)Br(-) immobilized PUFs have been critically studied. The negative values of DeltaH and DeltaS are interpreted as the exothermic and spontaneous reaction of gold(III) sorption onto unloaded PUFs and foams impregnated with THA(+)Br(-). The cellular structure of the PUFs sorbent offer unique advantages over conventional bulk-type sorbents in the rapid, versatile effective separation and/or preconcentration of gold ions.
Solving multiple scattering problems in planetary atmospheres
NASA Technical Reports Server (NTRS)
Irvine, W. M.; Lenoble, J.
1974-01-01
Definitions are provided of the basic concepts occurring in the solution of multiple scattering problems involving planetary atmospheres and attention is given to aspects of problem characterization. Approaches are considered for finding the answer to a particular problem without the performance of detailed calculations. The characteristics of albedos are investigated, taking into account semiinfinite atmospheres and finite atmospheres. Questions of surface illumination are discussed along with aspects related to energy deposition in the atmosphere, intensity, and polarization. Precise numerical methods are examined and analytical solutions are presented.
NASA Astrophysics Data System (ADS)
Biryukov, V. A.; Muratov, M. V.; Petrov, I. B.; Sannikov, A. V.; Favorskaya, A. V.
2015-10-01
Seismic responses from fractured geological layers are mathematically simulated by applying the grid-characteristic method on unstructured tetrahedral meshes with the use of high-performance computer systems. The method is intended for computing complicated spatial dynamical processes in complex heterogeneous media and is characterized by exact formulation of contact conditions. As a result, it can be applied to the simulation of seismic exploration problems, including in regions with a large number of inhomogeneities, examples of which are fractured structures. The use of unstructured tetrahedral meshes makes it possible to specify geological cracks of various shapes and spatial orientations. As a result, problems are solved in a formulation maximally close to an actual situation. A cluster of computers is used to improve the accuracy of the computation by optimizing its duration.
Seiverling, Laura; Hendy, Helen M; Williams, Keith
2011-01-01
The present study evaluated the 23-item Screening Tool for Feeding Problems (STEP; Matson & Kuhn, 2001) with a sample of children referred to a hospital-based feeding clinic to examine the scale's psychometric characteristics and then demonstrate how a children's revision of the STEP, the STEP-CHILD is associated with child and parent variables. Participants included 142 children (95 boys, 47 girls; mean age = 61.4 months; 43 with autism, 51 with other special needs, 48 with no special needs). Children ranged in age from 24 months to 18 years. Factor analysis revealed a 15-item STEP-CHILD with six subscales of child feeding problems: chewing problems, rapid eating, food refusal, food selectivity, vomiting, and stealing food. Mediation analysis documented that "overly permissive" actions by parents (such as infrequent insistence on eating during meals, or frequent preparation of Special Meals for children different than the family meal) explained over 34% of the links between children's feeding problems and poor weight and diet outcomes.
Backhaus, Autumn; Gholizadeh, Shadi; Godfrey, Kathryn M; Pittman, James; Afari, Niloofar
Previous research has demonstrated that veterans with posttraumatic stress disorder (PTSD) are at higher risk for aggression, hostility, and anger, potentially leading to problems with the law or disciplinary action while in the military. There have been calls for increased consideration of the unique aspects of the judicial system in legal matters with veterans involved. The bulk of the research so far has considered the link between PTSD, traumatic brain injury (TBI), and combat exposure, but little is known about the potential role of chronic pain and Military Sexual Trauma (MST) in a veteran's experience of anger, aggression, and discipline while in the military and legal concerns. The present study used retrospective cross-sectional health screening data in a sample of 1250 Iraq and Afghanistan veterans to examine the associations of demographic, service-related, and clinical characteristics with self-reported legal problems. A total of 440 veterans (34.6%) endorsed having experienced some type of problems with the law. Independent logistic regression analyses demonstrated that those who screened positive for PTSD, MST, TBI, and clinical levels of pain were more likely to report legal problems; only the associations with positive PTSD (p=0.001) and MST (p=0.007) screens remained significant in multivariate regression analyses. The findings underscore the need for a thorough psychological evaluation when veterans are involved in the legal system with a special emphasis on factors prevalent to Iraq and Afghanistan veterans.
Fabricating Cotton Analytical Devices.
Lin, Shang-Chi; Hsu, Min-Yen; Kuan, Chen-Meng; Tseng, Fan-Gang; Cheng, Chao-Min
2016-08-30
A robust, low-cost analytical device should be user-friendly, rapid, and affordable. Such devices should also be able to operate with scarce samples and provide information for follow-up treatment. Here, we demonstrate the development of a cotton-based urinalysis (i.e., nitrite, total protein, and urobilinogen assays) analytical device that employs a lateral flow-based format, and is inexpensive, easily fabricated, rapid, and can be used to conduct multiple tests without cross-contamination worries. Cotton is composed of cellulose fibers with natural absorptive properties that can be leveraged for flow-based analysis. The simple but elegant fabrication process of our cotton-based analytical device is described in this study. The arrangement of the cotton structure and test pad takes advantage of the hydrophobicity and absorptive strength of each material. Because of these physical characteristics, colorimetric results can persistently adhere to the test pad. This device enables physicians to receive clinical information in a timely manner and shows great potential as a tool for early intervention.
Aleluia, João; Ferrão, Paulo
2016-12-01
, despite some common characteristics shared among cities in developing Asia, their specific circumstances can significantly vary, even within the same country, calling for the need for context-specific waste management approaches. Set against this background, this paper proposes a guiding framework in the form of a matrix that maps out approaches observed in the management of municipal solid waste in cities of developing Asian countries as a function of the city dimension, share of organics on waste streams, and wealth generated by the city. The cities of Surabaya (Indonesia), Bangalore (India), Quy Nhon (Viet Nam), and Matale (Sri Lanka) are showcased as good practices in the region in the management of solid waste, with their experiences used to illustrate the framework laid out in the matrix. Copyright © 2016 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Hamida, Youcef
Metal Organic Frameworks (MOFs) exhibit many excellent physical properties including magnetic properties for potential applications in devices. More importantly for the subject of this thesis, MOFs are ideal for the realization of low dimensional magnetism because of the large selection of ligands connecting magnetic centers in making the framework. The materials studied in this thesis include ten magnetic MOFs of the form M(L1)(L2) [M = Cu, Ni, Co, Fe, Mn; L1 = NDC, bpdc, BDC, BODC, N3; L2 = DMF, H2O, TED, bpy]. Polycrystalline powder samples as well as single crystal samples were synthesized. Their crystal structures were determined, and their magnetic and thermodynamic properties were measured and analyzed. Eight of these materials were characterized as 1D magnets and two as 3D magnets. In the 1D case it is found that above Tm [the temperature at which the magnetic susceptibility chi(T) has a peak] the magnetic behavior of MOFs (S ≥ 1) can be well described with the Classical Fisher Model (CFM). Near and below TC the spins take a more definite orientation than allowed for in the CFM and hence the Ising Model (IM) was used for fitting. Both CFM and IM yield fairly consistent intrachain couplings ( J) when applied in their appropriate temperature region. To estimate the interchain exchange (J'), the susceptibility for a magnetic chain in the mean field of neighboring chains is used. In all cases, as expected, the ratio of J to J' was less than 10%. The special case of Cu(N3)2bpy ( S = ½) was analyzed with the spin ½ IM. Although the specific heat data (Ctotal) for most of the 1D MOFs showed no clear phase transition, a low temperature fit to the electron-phonon specific heats yielded apparent heavy fermion-like gamma values on the order of several hundred mJ/mol K2. The lattice specific heat (Clattice) was estimated using a Debye-Einstein hybrid model. Subtracting Clattice from Ctotal, magnetic specific heat ( CM) with a broad peak characteristic of low
Bochkov, N P; Khaitov, M N; Kuleshov, N P; Anfalova, T V; Diachenko, S S
1975-01-01
The paper comprises results of studying some demographic and populaton characteristics of the inhabitans of the Samarkand region as a whole and two villages, Karakent and Ishan, inhabited with Uzbeks-Khoja, a special religious-social caste in the past. It is shown that 87.4% of marriages in the Samarkand region are of international character (the information has been obtained on 7995 married couples). The frequency of consanguineous marriages is 11.6%, and among them 40.5% are first-cousin marriages and 39.1% are marriages of remote relatives. The coefficients of inbreeding are rather high among the Jewish, Tajik and Uzbek communities. The coefficient of inbreeding as a whole is F=0.0042 in this region and approaches to the maximal level, characterizing a panmix population. The average size of a family in the villages of Karakent and Ishan is approximately 4.0 persons. The values of reproductive performance, the nature of termination of pregnancies do not differ from those of panmix population. The percentage of intravillage and consanguineous marriages are 56% and 12.5% for the first village, and 25% and 2% for the second one respectively. The coefficient of inbreeding for karakent is F=0.0064, for Ishan--F=0.0014. Taking into consideration the historical development of the two villages and the cumulative data, the conclusion is drawn that Karakent is an isolate on a religious ground whereas Ishan is a disintegrated isolate.
Davenport, Thomas H
2006-01-01
We all know the power of the killer app. It's not just a support tool; it's a strategic weapon. Companies questing for killer apps generally focus all their firepower on the one area that promises to create the greatest competitive advantage. But a new breed of organization has upped the stakes: Amazon, Harrah's, Capital One, and the Boston Red Sox have all dominated their fields by deploying industrial-strength analytics across a wide variety of activities. At a time when firms in many industries offer similar products and use comparable technologies, business processes are among the few remaining points of differentiation--and analytics competitors wring every last drop of value from those processes. Employees hired for their expertise with numbers or trained to recognize their importance are armed with the best evidence and the best quantitative tools. As a result, they make the best decisions. In companies that compete on analytics, senior executives make it clear--from the top down--that analytics is central to strategy. Such organizations launch multiple initiatives involving complex data and statistical analysis, and quantitative activity is managed atthe enterprise (not departmental) level. In this article, professor Thomas H. Davenport lays out the characteristics and practices of these statistical masters and describes some of the very substantial changes other companies must undergo in order to compete on quantitative turf. As one would expect, the transformation requires a significant investment in technology, the accumulation of massive stores of data, and the formulation of company-wide strategies for managing the data. But, at least as important, it also requires executives' vocal, unswerving commitment and willingness to change the way employees think, work, and are treated.
Kong, Grace; Tsai, Jack; Pilver, Corey E.; Tan, Hwee Sim; Hoff, Rani A.; Cavallo, Dana; Krishnan-Sarin, Suchitra; Steinberg, Marvin A.; Rugle, Loreen; Potenza, Marc N.
2013-01-01
Studies of Asian-American adults have found high estimates of problematic gambling. However, little is known about gambling behaviors and associated measures among Asian-American adolescents. This study examined gambling perceptions and behaviors and health/functioning characteristics stratified by problem-gambling severity and Asian-American and Caucasian race using cross-sectional survey data of 121 Asian-American and 1,659 Caucasian high-school students. Asian-American and Caucasian adolescents significantly differed on problem-gambling severity, with Asian-American adolescents more often reporting not gambling (24.8% vs. 16.4%), but when they did report gambling, they showed higher levels of at-risk/problem gambling (30.6% vs. 26.4%). Parental approval or disapproval of adolescent gambling also significantly differed between races, with Asian-American adolescents more likely to perceive both parental disapproval (50.0% vs. 38.2%) and approval (19.3% vs. 9.6%) of gambling. Asian-American adolescents were also more likely to express concern about gambling among close family members (25.2% vs. 11.6%). Among Asian-American adolescents, stronger associations were observed between at-risk/problem gambling and smoking cigarettes (interaction odds ratio=12.6). In summary, differences in problem-gambling severity and gambling perceptions indicate possible cultural differences in familial attitudes towards gambling. Stronger links between cigarette smoking and risky/problematic gambling amongst Asian-American adolescents suggest that prevention and treatment efforts targeting youth addictions consider cultural differences. PMID:24183532
Kong, Grace; Tsai, Jack; Pilver, Corey E; Tan, Hwee Sim; Hoff, Rani A; Cavallo, Dana A; Krishnan-Sarin, Suchitra; Steinberg, Marvin A; Rugle, Loreen; Potenza, Marc N
2013-12-30
Studies of Asian-American adults have found high estimates of problematic gambling. However, little is known about gambling behaviors and associated measures among Asian-American adolescents. This study examined gambling perceptions and behaviors and health/functioning characteristics stratified by problem-gambling severity and Asian-American and Caucasian race using cross-sectional survey data of 121 Asian-American and 1659 Caucasian high-school students. Asian-American and Caucasian adolescents significantly differed on problem-gambling severity, with Asian-American adolescents more often reporting not gambling (24.8% vs. 16.4%), but when they did report gambling, they showed higher levels of at-risk/problem gambling (30.6% vs. 26.4%). Parental approval or disapproval of adolescent gambling also significantly differed between races, with Asian-American adolescents more likely to perceive both parental disapproval (50.0% vs. 38.2%) and approval (19.3% vs. 9.6%) of gambling. Asian-American adolescents were also more likely to express concern about gambling among close family members (25.2% vs. 11.6%). Among Asian-American adolescents, stronger associations were observed between at-risk/problem gambling and smoking cigarettes (interaction odds ratio=12.6). In summary, differences in problem-gambling severity and gambling perceptions indicate possible cultural differences in familial attitudes towards gambling. Stronger links between cigarette smoking and risky/problematic gambling amongst Asian-American adolescents suggest that prevention and treatment efforts targeting youth addictions consider cultural differences. © 2013 Published by Elsevier Ireland Ltd.
Fujiwara, Kyoko; Tsukishima, Eri; Kishi, Reiko
2003-07-01
The aims of this study were to describe job characteristics for daytime and shift workers in home care services for the elderly and to clarify health care in the work setting, social support, and job satisfaction and possibilities. A self-reported questionnaire was given to 433 home care workers, both full time and part time (more than 15 hours), at 35 institutions that provide home care services to residents of Sapporo (return rate; 80.2%). The following issues were investigated: job content (physical care, assistance with housework, and advice), specialty, job satisfaction, possibilities, job training, health care and social support. The results were compared among employed types: full-time and part-time daytime and shift workers using the t-test or the Fisher's test. The participants demonstrated high dissatisfaction with wages, physical uneasiness themselves and limited social support from their supervisors. Especially full-time workers were dissatisfied with the payment, whereas part-time workers complained about insufficient attention to the prevention of lumbago. It was found that part-time daytime workers were given insufficient on-job-training and education for prevention of infection, and that full-time shift workers greatly wished to leave the employment. However, the home care workers were satisfied with their job itself and expected to continue their work. Furthermore, half of the part-time workers hoped to work full time. Health management and educational training for part-time workers may be necessary to improve the quality of care services and protection of health. Promotion of full time employment and reconsideration of working condition might be necessary to provide sufficient home care services.
Kido, Yasuhiro; Sakazume, Satoru; Abe, Yoshiko; Oto, Yuji; Itabashi, Hisashi; Shiraishi, Masahisa; Yoshino, Atsunori; Tanaka, Yuriko; Obata, Kazuo; Murakami, Nobuyuki; Nagai, Toshiro
2013-09-01
Prader-Willi syndrome (PWS), a complex genetic disorder, arises from suppressed expression of paternally inherited imprinted genes on chromosome 15q11-q13. Characteristics include short stature, intellectual disability, behavioral problems, hypogonadism, obesity, and reduced bone and muscle mass. Testosterone replacement (TR) remains controversial due to concerns regarding behavioral problems. To evaluate the effects of TR on secondary sexual characteristics, body composition, and behavior in adult males with PWS, 22 male PWS patients over the age of 16 with behavioral scores of less than grade 4 on the Modified Overt Aggression Scale (MOAS) underwent monthly intramuscular TR (125 mg). Pubertal change, body composition and behavior were evaluated before and after 24 months of therapy. Serum testosterone, LH, and FSH did not change. Increased pubic hair was observed in 16 of 22 patients (72.7%). Percent body fat decreased from 47.55 ± 2.06% to 39.75 ± 1.60% (n = 18) (P = 0.018). Bone mineral density increased from 0.8505 ± 0.0426 g/cm(2) to 0.9035 ± 0.0465 g/cm(2) (n = 18) (P = 0.036), and lean body mass increased from 18093.4 ± 863.0 g to 20312.1 ± 1027.2 g (n = 18) (P = 0.009). The MOAS was unchanged, from 4.5 ± 2.0 at the beginning of the study to 3.0 ± 1.7 at the end of study indicating no increase in aggression. No behavioral problems were observed. Based on this pilot study, TR with 125 mg monthly is a potentially safe and useful intervention for adult males with PWS. Copyright © 2013 Wiley Periodicals, Inc.
NASA Astrophysics Data System (ADS)
Zhang, Ji; Yuan, Han; Zhao, Jian; Mei, Ning
2016-12-01
To identify the ingredients of an oil-water mixture in petroleum production or petrochemicals process, a method based on a characteristic liquid inverse problem was developed by clarifying its real viscosity and thermal conductivity. A heat transfer and fluid flow model for an oil-water mixture was established for tube flow in this paper. By means of the measured temperature distribution in the tube, the thermal physical properties of the oil-water mixture can be obtained by the governing equations in the model according to their characteristics as a Newtonian or non-Newtonian fluid. The fluid characteristic can be deduced by the rheological properties of the oil-water mixture. Both the Newtonian fluid and non-Newtonian fluid governing equations were established to determine the mixture components. Experiments were also conducted to verify the numerical solutions for the ingredients of the oil-water mixture. The comparison between theoretical solutions and experimental results shows that the maximum error based on the suitable fluid model is 3.11 %, which demonstrated the feasibility of the proposed method for estimating the ingredients of an oil-water mixture.
42 CFR 493.1289 - Standard: Analytic systems quality assessment.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 42 Public Health 5 2014-10-01 2014-10-01 false Standard: Analytic systems quality assessment. 493... Nonwaived Testing Analytic Systems § 493.1289 Standard: Analytic systems quality assessment. (a) The..., assess, and when indicated, correct problems identified in the analytic systems specified in §§ 493.1251...
42 CFR 493.1289 - Standard: Analytic systems quality assessment.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 5 2013-10-01 2013-10-01 false Standard: Analytic systems quality assessment. 493... Nonwaived Testing Analytic Systems § 493.1289 Standard: Analytic systems quality assessment. (a) The..., assess, and when indicated, correct problems identified in the analytic systems specified in §§ 493.1251...
42 CFR 493.1289 - Standard: Analytic systems quality assessment.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 5 2012-10-01 2012-10-01 false Standard: Analytic systems quality assessment. 493... Nonwaived Testing Analytic Systems § 493.1289 Standard: Analytic systems quality assessment. (a) The..., assess, and when indicated, correct problems identified in the analytic systems specified in §§ 493.1251...
Analytical solutions of moisture flow equations and their numerical evaluation
Gibbs, A.G.
1981-04-01
The role of analytical solutions of idealized moisture flow problems is discussed. Some different formulations of the moisture flow problem are reviewed. A number of different analytical solutions are summarized, including the case of idealized coupled moisture and heat flow. The evaluation of special functions which commonly arise in analytical solutions is discussed, including some pitfalls in the evaluation of expressions involving combinations of special functions. Finally, perturbation theory methods are summarized which can be used to obtain good approximate analytical solutions to problems which are too complicated to solve exactly, but which are close to an analytically solvable problem.
Instrumentation for analytical scale supercritical fluid chromatography.
Berger, Terry A
2015-11-20
Analytical scale supercritical fluid chromatography (SFC) is largely a sub-discipline of high performance liquid chromatography (HPLC), in that most of the hardware and software can be used for either technique. The aspects that separate the 2 techniques stem from the use of carbon dioxide (CO2) as the main component of the mobile phase in SFC. The high compressibility and low viscosity of CO2 mean that pumps, and autosamplers designed for HPLC either need to be modified or an alternate means of dealing with compressibility needs to be found. The inclusion of a back pressure regulator and a high pressure flow cell for any UV-Vis detector are also necessary. Details of the various approaches, problems and solutions are described. Characteristics, such as adiabatic vs. isothermal compressibility, thermal gradients, and refractive index issues are dealt with in detail. Copyright © 2015 Elsevier B.V. All rights reserved.
Sande, Matej
2016-01-01
The study presents the characteristics of the use of new psychoactive substances (NPS), the perceived problems experienced by users, and the reasons for cessation or cutting down. The research focused mainly on synthetic cathinones and the use of 3-MMC in Slovenia. In order to research the characteristics of NPS use, we used a questionnaire which had been developed to determine the characteristics of the use of ATS and cocaine in the context of nightlife and was elaborated in our study on the use of mephedrone. The final non-representative sample included 249 users of NPS from Slovenia, who had completed an on-line survey over a period of 5 months in 2014. Part of the sampling was conducted on the ground and with the help of peer-groups. DrogArt's outreach workers and correspondents visited open public places, clubs, and discotheques to encourage users to participate in the survey. Most users of NPS in Slovenia have tried NPS from the groups of synthetic cathinones and amphetamines. Most respondents included in the sample (67.9%) have tried 3-MMC, while 43.0% have tried methylone and 37.3% have tried mephedrone (4-MMC). Users attributed greater risks to the use of new drugs and preferred the effects of traditional drugs to those of new drugs. The most frequently reported problems were depression (55.2% of users), concentration difficulties (44.0%), damage to the mucous membrane of the nose and to the throat (39.8%), feelings of fear and anxiety (39.4%), and tingling in the arms or legs (34.4%). The main reasons for cutting down or discontinuing the use of NPS were 'fear of the health consequences', 'actual health consequences', and 'growing weary of using'. Among users of NPS, 7% have sought help, while 9.1% have considered doing so. The results also highlight differences between the NPS drug markets in Slovenia and the United Kingdom. In 2014, the most frequently used NPS in Slovenia were synthetic cathinones such as 3-MMC. Users experienced various problems
Ricci-Cabello, Ignacio; Reeves, David; Bell, Brian G; Valderas, Jose M
2017-08-07
To identify patient and family practice characteristics associated with patient-reported experiences of safety problems and harm. Cross-sectional study combining data from the individual postal administration of the validated Patient Reported Experiences and Outcomes of Safety in Primary Care (PREOS-PC) questionnaire to a random sample of patients in family practices (response rate=18.4%) and practice-level data for those practices obtained from NHS Digital. We built linear multilevel multivariate regression models to model the association between patient-level (clinical and sociodemographic) and practice-level (size and case-mix, human resources, indicators of quality and safety of care, and practice safety activation) characteristics, and outcome measures. practices distributed across five regions in the North, Centre and South of England. 1190 patients registered in 45 practices purposefully sampled (maximal variation in practice size and levels of deprivation). Self-reported safety problems, harm and overall perception of safety. Higher self-reported levels of safety problems were associated with younger age of patients (beta coefficient 0.15) and lower levels of practice safety activation (0.44). Higher self-reported levels of harm were associated with younger age (0.13) and worse self-reported health status (0.23). Lower self-reported healthcare safety was associated with lower levels of practice safety activation (0.40). The fully adjusted models explained 4.5% of the variance in experiences of safety problems, 8.6% of the variance in harm and 4.4% of the variance in perceptions of patient safety. Practices' safety activation levels and patients' age and health status are associated with patient-reported safety outcomes in English family practices. The development of interventions aimed at improving patient safety outcomes would benefit from focusing on the identified groups. © Article author(s) (or their employer(s) unless otherwise stated in the text of
NASA Astrophysics Data System (ADS)
Batory, Krzysztof J.; Govindjee; Andersen, Dale; Presley, John; Lucas, John M.; Sears, S. Kelly; Vali, Hojatollah
Unambiguous detection of extraterrestrial nitrogenous hydrocarbon microbiology requires an instrument both to recognize potential biogenic specimens and to successfully discriminate them from geochemical settings. Such detection should ideally be in-situ and not jeopardize other experiments by altering samples. Taken individually most biomarkers are inconclusive. For example, since amino acids can be synthesized abiotically they are not always considered reliable biomarkers. An enantiomeric imbalance, which is characteristic of all terrestrial life, may be questioned because chirality can also be altered abiotically. However, current scientific understanding holds that aggregates of identical proteins or proteinaceous complexes, with their well-defined amino acid residue sequences, are indisputable biomarkers. Our paper describes the Mars Analytical Microimager, an instrument for the simultaneous imaging of generic autofluorescent biomarkers and overall morphology. Autofluorescence from ultraviolet to near-infrared is emitted by all known terrestrial biology, and often as consistent complex bands uncharacteristic of abiotic mineral luminescence. The MAM acquires morphology, and even sub-micron morphogenesis, at a 3-centimeter working distance with resolution approaching a laser scanning microscope. Luminescence is simultaneously collected via a 2.5-micron aperture, thereby permitting accurate correlation of multi-dimensional optical behavior with specimen morphology. A variable wavelength excitation source and photospectrometer serve to obtain steady-state and excitation spectra of biotic and luminescent abiotic sources. We believe this is the first time instrumentation for detecting hydrated or desiccated microbiology non-destructively in-situ has been demonstrated. We have obtained excellent preliminary detection of biota and inorganic matrix discrimination from terrestrial polar analogues, and perimetric morphology of individual magnetotactic bacteria. Proposed
Analytical Chemistry Division's sample transaction system
Stanton, J.S.; Tilson, P.A.
1980-10-01
The Analytical Chemistry Division uses the DECsystem-10 computer for a wide range of tasks: sample management, timekeeping, quality assurance, and data calculation. This document describes the features and operating characteristics of many of the computer programs used by the Division. The descriptions are divided into chapters which cover all of the information about one aspect of the Analytical Chemistry Division's computer processing.
Problems for Computer Mathematics.
ERIC Educational Resources Information Center
Allison, Ronald; And Others
This booklet contains some 80 problems in mathematics suitable for computer solution. The problems range from very simple to complex. Problems have been included from most mathematic disciplines, including number theory, analytical geometry, probability and statistics, trigonometry, equations, and sequence and limits. For the most part these…
ERIC Educational Resources Information Center
MacNeill, Sheila; Campbell, Lorna M.; Hawksey, Martin
2014-01-01
This article presents an overview of the development and use of analytics in the context of education. Using Buckingham Shum's three levels of analytics, the authors present a critical analysis of current developments in the domain of learning analytics, and contrast the potential value of analytics research and development with real world…
ERIC Educational Resources Information Center
Oblinger, Diana G.
2012-01-01
Talk about analytics seems to be everywhere. Everyone is talking about analytics. Yet even with all the talk, many in higher education have questions about--and objections to--using analytics in colleges and universities. In this article, the author explores the use of analytics in, and all around, higher education. (Contains 1 note.)
Miller, Racheli; Hilsenroth, Mark
2016-12-12
This investigation's goal was to assess the concurrent validity of the four scales of the Anaclitic and Introjective Depression Assessment (AIDA), a newly developed clinician-rated measure, and the Inventory of Interpersonal Problems Circumplex Scales (IIP-64). The AIDA is composed of Shedler-Westen Assessment Procedure items and is comprised of two primitive and two more mature scales of introjective and anaclitic personality types. Specific predictions of relationships were made and are discussed further in this paper. The participants in this study were 106 outpatients engaged in psychodynamic psychotherapy. Patients completed the IIP-64 upon assessment and were rated by their therapist on the Shedler-Westen Assessment Procedure 200 (SWAP-200). The present findings demonstrated several expected relationships between the SWAP-derived AIDA and the IIP-64. Primitive levels of Anaclitic and Introjective characteristics on the AIDA were related to more difficulties involving Affiliation and Dominance on the IIP. The primitive Introjective-Dismissive (Dismissive Depression) scale was related to difficulties involving high Dominance and low Affiliation. The more adaptive Introjective-Self-Critical (Self-Critical Depression) scale was not related to any interpersonal problem. The more adaptive Anaclitic-Needy (Needy Depression) scale was related to difficulties involving high Affiliation, and the primitive Anaclitic-Submissive (Submissive Depression) scale was associated with difficulties related to high Affiliation, as well as problems related to low Dominance in one of two domains. Our results bolster the concurrent validity of the four AIDA scales and add to current knowledge of the differential interpersonal patterns of individuals with more mature and primitive levels of anaclitic and introjective personality types. Copyright © 2016 John Wiley & Sons, Ltd.
Collaborative Analytical Toolbox version 1.0
2008-08-21
The purpose of the Collaborative Analytical Toolbox (CAT) is to provide a comprehensive, enabling, collaborative problem solving environment that enables users to more effectively apply and improve their analytical and problem solving capabilities. CAT is a software framework for integrating other tools and data sources. It includes a set of core services for collaboration and information exploration and analysis, and a framework that facilitates quickly integrating new ideas, techniques, and tools with existing data sources.
Analytical description of the electrodynamic properties of metallic photonic crystals
NASA Astrophysics Data System (ADS)
Vetluzhskii, A. Yu.; Lomukhin, Yu. L.
2017-08-01
We consider the excitation by a dipole of metallic photonic crystals—systems of infinitely extended parallel-oriented metallic cylinders with a small circular cross section. Based on the rigorous statement of the problem, analytical expressions are obtained that make it possible to give a simple estimate of frequencies that determine the band gap edges in the spectrum of eigenstates of such a crystal and, also, to describe the amplitude characteristics of radiation in the low-frequency range, in which the approximations used in our study are correct. We compare our results with those obtained by strictly numerical simulation.
Big Data Analytics in Healthcare
Belle, Ashwin; Thiagarajan, Raghuram; Soroushmehr, S. M. Reza; Beard, Daniel A.
2015-01-01
The rapidly expanding field of big data analytics has started to play a pivotal role in the evolution of healthcare practices and research. It has provided tools to accumulate, manage, analyze, and assimilate large volumes of disparate, structured, and unstructured data produced by current healthcare systems. Big data analytics has been recently applied towards aiding the process of care delivery and disease exploration. However, the adoption rate and research development in this space is still hindered by some fundamental problems inherent within the big data paradigm. In this paper, we discuss some of these major challenges with a focus on three upcoming and promising areas of medical research: image, signal, and genomics based analytics. Recent research which targets utilization of large volumes of medical data while combining multimodal data from disparate sources is discussed. Potential areas of research within this field which have the ability to provide meaningful impact on healthcare delivery are also examined. PMID:26229957
Big Data Analytics in Healthcare.
Belle, Ashwin; Thiagarajan, Raghuram; Soroushmehr, S M Reza; Navidi, Fatemeh; Beard, Daniel A; Najarian, Kayvan
2015-01-01
The rapidly expanding field of big data analytics has started to play a pivotal role in the evolution of healthcare practices and research. It has provided tools to accumulate, manage, analyze, and assimilate large volumes of disparate, structured, and unstructured data produced by current healthcare systems. Big data analytics has been recently applied towards aiding the process of care delivery and disease exploration. However, the adoption rate and research development in this space is still hindered by some fundamental problems inherent within the big data paradigm. In this paper, we discuss some of these major challenges with a focus on three upcoming and promising areas of medical research: image, signal, and genomics based analytics. Recent research which targets utilization of large volumes of medical data while combining multimodal data from disparate sources is discussed. Potential areas of research within this field which have the ability to provide meaningful impact on healthcare delivery are also examined.
ALARA: Analytic and Laplacian adaptive radioactivity analysis
NASA Astrophysics Data System (ADS)
Wilson, Paul Philip Hood
While many codes have been written to compute the induced activation and changes in composition caused by neutron irradiation, most of those which are still being updated are only slowly adding functionality and not improving the accuracy, speed and usability of their existing methods. ALARA moves forward in all four of these areas, with primary importance being placed on the accuracy and speed of solution. By carefully analyzing the various ways to model the physical system, the methods to solve the mathematical problem and the interaction between these two issues, ALARA chooses an optimum combination to achieve high accuracy, fast computation, and enhanced versatility and ease of use. In addition to a set of base features, standard to any activation code, ALARA offers a number of extensions, including arbitrary hierarchical irradiation schedules and a form of reverse problem for calculating the detailed activation of specific isotopes. The physical system is modeled using advanced linear chains, which include the contributions from straightened loops in the reaction scheme, while the truncation philosophy minimizes the discrepancies between the model and the real problem. The mathematical method is then adaptively chosen based on the characteristics of each linear chain to use analytically exact methods when possible and an accurate expansion technique otherwise. ALARA has been successfully validated against established fusion activation codes using a standard activation benchmark problem. In addition to demonstrating ALARA 's accuracy, this validation excerise has demonstrated its speed. Furthermore, by extending the benchmark problem to validate its advanced features, ALARA 's flexibility has been proven. With its modern computational techniques and continuing development, it is hoped that ALARA will become a widely used code for the activation analysis of nuclear systems.
Analytical and Computational Aspects of Collaborative Optimization
NASA Technical Reports Server (NTRS)
Alexandrov, Natalia M.; Lewis, Robert Michael
2000-01-01
Bilevel problem formulations have received considerable attention as an approach to multidisciplinary optimization in engineering. We examine the analytical and computational properties of one such approach, collaborative optimization. The resulting system-level optimization problems suffer from inherent computational difficulties due to the bilevel nature of the method. Most notably, it is impossible to characterize and hence identify solutions of the system-level problems because the standard first-order conditions for solutions of constrained optimization problems do not hold. The analytical features of the system-level problem make it difficult to apply conventional nonlinear programming algorithms. Simple examples illustrate the analysis and the algorithmic consequences for optimization methods. We conclude with additional observations on the practical implications of the analytical and computational properties of collaborative optimization.
Data Intensive Architecture for Scalable Cyber Analytics
Olsen, Bryan K.; Johnson, John R.; Critchlow, Terence J.
2011-11-15
Cyber analysts are tasked with the identification and mitigation of network exploits and threats. These compromises are difficult to identify due to the characteristics of cyber communication, the volume of traffic, and the duration of possible attack. It is necessary to have analytical tools to help analysts identify anomalies that span seconds, days, and weeks. Unfortunately, providing analytical tools effective access to the volumes of underlying data requires novel architectures, which is often overlooked in operational deployments. Our work is focused on a summary record of communication, called a flow. Flow records are intended to summarize a communication session between a source and a destination, providing a level of aggregation from the base data. Despite this aggregation, many enterprise network perimeter sensors store millions of network flow records per day. The volume of data makes analytics difficult, requiring the development of new techniques to efficiently identify temporal patterns and potential threats. The massive volume makes analytics difficult, but there are other characteristics in the data which compound the problem. Within the billions of records of communication that transact, there are millions of distinct IP addresses involved. Characterizing patterns of entity behavior is very difficult with the vast number of entities that exist in the data. Research has struggled to validate a model for typical network behavior with hopes it will enable the identification of atypical behavior. Complicating matters more, typically analysts are only able to visualize and interact with fractions of data and have the potential to miss long term trends and behaviors. Our analysis approach focuses on aggregate views and visualization techniques to enable flexible and efficient data exploration as well as the capability to view trends over long periods of time. Realizing that interactively exploring summary data allowed analysts to effectively identify
Characteristic formulation for metric f (R ) gravity
NASA Astrophysics Data System (ADS)
Mongwane, Bishop
2017-07-01
In recent years, the characteristic formulation of numerical relativity has found increasing use in the extraction of gravitational radiation from numerically generated spacetimes. In this paper, we formulate the characteristic initial value problem for f (R ) gravity. We consider, in particular, the vacuum field equations of Metric f (R ) gravity in the Jordan frame, without utilizing the dynamical equivalence with scalar-tensor theories. We present the full hierarchy of nonlinear hypersurface and evolution equations necessary for numerical implementation in both tensorial and eth forms. Furthermore, we specialize the resulting equations to situations where the spacetime is almost Minkowski and almost Schwarszchild using standard linearization techniques. We obtain analytic solutions for the dominant ℓ=2 mode and show that they satisfy the concomitant constraints. These results are ideally suited as testbed solutions for numerical codes. Finally, we point out that the characteristic formulation can be used as a complementary analytic tool to the 1 +1 +2 semitetrad formulation.
Analytical solution approximation for bearing
NASA Astrophysics Data System (ADS)
Hanafi, Lukman; Mufid, M. Syifaul
2017-08-01
The purpose of lubrication is to separate two surfaces sliding past each other with a film of some material which can be sheared without causing any damage to the surfaces. Reynolds equation is a basic equation for fluid lubrication which is applied in the bearing problem. This equation can be derived from Navier-Stokes equation and continuity equation. In this paper Reynolds equation is solved using analytical approximation by making simplification to obtain pressure distribution.
Analytical Challenges in Biotechnology.
ERIC Educational Resources Information Center
Glajch, Joseph L.
1986-01-01
Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)
Analytical Challenges in Biotechnology.
ERIC Educational Resources Information Center
Glajch, Joseph L.
1986-01-01
Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)
Mumghamba, E. G.
2017-01-01
Aim. To assess self-reported halitosis, oral hygiene practices, oral health conditions, general health problems, sociodemographic factors, and behavioural and psychological characteristics among workers in Ilala and Temeke municipals. Materials and Methods. This was a cross-sectional descriptive study. Four hundred workers were recruited using a self-administered structured questionnaire. Results. Self-reported tooth brushing practice was 100%, tongue cleaning 58.5%, dental flossing 4.3%, gum bleeding on tooth brushing 79.3%, presence of hard deposits on teeth 32%, mobile teeth 15.3%, and self-reported halitosis (SRH) 48.5%. Tea users were 95%, coffee users 75.8%, smokers 21%, and alcohol consumers 47%. The SRH was significantly associated with bleeding gums, hard deposits, and mobile and malaligned teeth. Tongue cleaning and regular change of toothbrush were associated with low prevalence of SRH (P < 0.001). Higher occurrence of SRH was significantly related to low education and smoking. Conclusion. Self-reported halitosis was prevalent among workers and was significantly associated with bleeding gums, hard dental deposits, mobile teeth, and smoking. All participants brushed their teeth and cleaned the tongue regularly but use of dental floss was extremely low. Oral health education and health promotion are recommended. PMID:28280509
Kayombo, C M; Mumghamba, E G
2017-01-01
Aim. To assess self-reported halitosis, oral hygiene practices, oral health conditions, general health problems, sociodemographic factors, and behavioural and psychological characteristics among workers in Ilala and Temeke municipals. Materials and Methods. This was a cross-sectional descriptive study. Four hundred workers were recruited using a self-administered structured questionnaire. Results. Self-reported tooth brushing practice was 100%, tongue cleaning 58.5%, dental flossing 4.3%, gum bleeding on tooth brushing 79.3%, presence of hard deposits on teeth 32%, mobile teeth 15.3%, and self-reported halitosis (SRH) 48.5%. Tea users were 95%, coffee users 75.8%, smokers 21%, and alcohol consumers 47%. The SRH was significantly associated with bleeding gums, hard deposits, and mobile and malaligned teeth. Tongue cleaning and regular change of toothbrush were associated with low prevalence of SRH (P < 0.001). Higher occurrence of SRH was significantly related to low education and smoking. Conclusion. Self-reported halitosis was prevalent among workers and was significantly associated with bleeding gums, hard dental deposits, mobile teeth, and smoking. All participants brushed their teeth and cleaned the tongue regularly but use of dental floss was extremely low. Oral health education and health promotion are recommended.
Fröberg, Frida; Rosendahl, Ingvar K; Abbott, Max; Romild, Ulla; Tengström, Anders; Hallqvist, Johan
2015-09-01
We aimed to estimate the incidence of a first episode of problem gambling among Swedish 16-24 year-olds by demographic and socio-economic characteristics, and to compare the incidence between 16-24 and 25-44 year-olds, and between young women and men. Other aims were to estimate the proportions of recovery and incidence in recurrent problem gambling, and prevalence of problem gambling among 16-44 year-olds in Sweden. We selected 4,358 participants aged 16-44 from the nationally representative Swedish Longitudinal Gambling Study in 2008/2009 and 2009/2010. The primary outcome measure was a first episode of problem gambling during 12 months before the follow-up as measured by the Problem Gambling Severity Index among participants without a history of problem gambling at baseline. The incidence proportion of a first episode of problem gambling among 16-24 year-olds was 2.26% (95% confidence interval 1.52-3.36); three times lower among females (1.14; 0.42-3.07%) than males (3.32; 2.19-5.01%). Young age and household financial problems were associated with first episode problem gambling among young women. Among 25-44 year-olds, the incidence proportion of a first episode of problem gambling was 0.81% (0.41-1.56). Recovery from problem gambling was high, in particular among females. Individual transitions from problem gambling to recovery and to recurrent problem gambling, between baseline and follow-up, were common regardless of age. This study adds further evidence to research suggesting that there is a high mobility in and out of problem gambling over time on an individual level. The high incidence of first episode problem gambling among youth in Sweden stresses the importance of prevention of problem gambling at an early age.
Analyticity without Differentiability
ERIC Educational Resources Information Center
Kirillova, Evgenia; Spindler, Karlheinz
2008-01-01
In this article we derive all salient properties of analytic functions, including the analytic version of the inverse function theorem, using only the most elementary convergence properties of series. Not even the notion of differentiability is required to do so. Instead, analytical arguments are replaced by combinatorial arguments exhibiting…
Design of Analytical Run Length for Clinical Chemistry Analytes.
Hu, Litao; Wang, Wei; Xiao, Yaling; Wang, Zhiguo
2015-01-01
The expected number of unacceptable patient results E (Nu) can be set as a patient-based quality goal. Analytical run length can be designed to limit E (Nu) < 1. The new internal quality control (IQC) strategy and length of analytical run for each analyte was applied to routine IQC paralleled with the way before redesign. IQC charts were produced by QC test results to analyze and compare the performance of out-of-control error detection. Optimal analytical run lengths designed by the quality control computer software QCCS 2008 were 39 for albumin, 61 for cholesterol, 900 for triglycerides, 112 for aspartate aminotransferase, 279 for lactate dehydrogenase, 267 for alcaline phospatase, 363 for total bilirubin, 151 for ceatinine, 230 for uric acid, 46 for phosphorus PHOS, 158 for carbon dioxide, and 580 for glucose. After being redesigned, IQC strategies for ALB, CHOL, and PHOS detected more out-of-control error than before and achieved more cost-effectiveness. Using E (Nu) as a QC performance measure, frequency of QC testing can be objectively designed. Additionally, new QC strategies can help find more problems of testing systems and promote efficiency and cost savings.
Tien, Kai-Wen; Kulvatunyou, Boonserm; Jung, Kiwook; Prabhu, Vittaldas
2017-01-01
As cloud computing is increasingly adopted, the trend is to offer software functions as modular services and compose them into larger, more meaningful ones. The trend is attractive to analytical problems in the manufacturing system design and performance improvement domain because 1) finding a global optimization for the system is a complex problem; and 2) sub-problems are typically compartmentalized by the organizational structure. However, solving sub-problems by independent services can result in a sub-optimal solution at the system level. This paper investigates the technique called Analytical Target Cascading (ATC) to coordinate the optimization of loosely-coupled sub-problems, each may be modularly formulated by differing departments and be solved by modular analytical services. The result demonstrates that ATC is a promising method in that it offers system-level optimal solutions that can scale up by exploiting distributed and modular executions while allowing easier management of the problem formulation.
Schauber, Stefan K; Hecht, Martin; Nouns, Zineb M; Kuhlmey, Adelheid; Dettmer, Susanne
2015-10-01
In medical education, the effect of the educational environment on student achievement has primarily been investigated in comparisons between traditional and problem-based learning (PBL) curricula. As many of these studies have reached no clear conclusions on the superiority of the PBL approach, the effect of curricular reform on student performance remains an issue. We employed a theoretical framework that integrates antecedents of student achievement from various psychosocial domains to examine how students interact with their curricular environment. In a longitudinal study with N = 1,646 participants, we assessed students in a traditional and a PBL-centered curriculum. The measures administered included students' perception of the learning environment, self-efficacy beliefs, positive study-related affect, social support, indicators of self-regulated learning, and academic achievement assessed through progress tests. We compared the relations between these characteristics in the two curricular environments. The results are two-fold. First, substantial relations of various psychosocial domains and their associations with achievement were identified. Second, our analyses indicated that there are no substantial differences between traditional and PBL-based curricula concerning the relational structure of psychosocial variables and achievement. Drawing definite conclusions on the role of curricular-level interventions in the development of student's academic achievement is constrained by the quasi-experimental design as wells as the selection of variables included. However, in the specific context described here, our results may still support the view of student activity as the key ingredient in the acquisition of achievement and performance.
Analytical optical scattering in clouds
NASA Technical Reports Server (NTRS)
Phanord, Dieudonne D.
1989-01-01
An analytical optical model for scattering of light due to lightning by clouds of different geometry is being developed. The self-consistent approach and the equivalent medium concept of Twersky was used to treat the case corresponding to outside illumination. Thus, the resulting multiple scattering problem is transformed with the knowledge of the bulk parameters, into scattering by a single obstacle in isolation. Based on the size parameter of a typical water droplet as compared to the incident wave length, the problem for the single scatterer equivalent to the distribution of cloud particles can be solved either by Mie or Rayleigh scattering theory. The super computing code of Wiscombe can be used immediately to produce results that can be compared to the Monte Carlo computer simulation for outside incidence. A fairly reasonable inverse approach using the solution of the outside illumination case was proposed to model analytically the situation for point sources located inside the thick optical cloud. Its mathematical details are still being investigated. When finished, it will provide scientists an enhanced capability to study more realistic clouds. For testing purposes, the direct approach to the inside illumination of clouds by lightning is under consideration. Presently, an analytical solution for the cubic cloud will soon be obtained. For cylindrical or spherical clouds, preliminary results are needed for scattering by bounded obstacles above or below a penetrable surface interface.