Science.gov

Sample records for posteriori parameter choice

  1. Marginal Maximum A Posteriori Item Parameter Estimation for the Generalized Graded Unfolding Model

    ERIC Educational Resources Information Center

    Roberts, James S.; Thompson, Vanessa M.

    2011-01-01

    A marginal maximum a posteriori (MMAP) procedure was implemented to estimate item parameters in the generalized graded unfolding model (GGUM). Estimates from the MMAP method were compared with those derived from marginal maximum likelihood (MML) and Markov chain Monte Carlo (MCMC) procedures in a recovery simulation that varied sample size,…

  2. An adaptive regularization parameter choice strategy for multispectral bioluminescence tomography

    SciTech Connect

    Feng Jinchao; Qin Chenghu; Jia Kebin; Han Dong; Liu Kai; Zhu Shouping; Yang Xin; Tian Jie

    2011-11-15

    Purpose: Bioluminescence tomography (BLT) provides an effective tool for monitoring physiological and pathological activities in vivo. However, the measured data in bioluminescence imaging are corrupted by noise. Therefore, regularization methods are commonly used to find a regularized solution. Nevertheless, for the quality of the reconstructed bioluminescent source obtained by regularization methods, the choice of the regularization parameters is crucial. To date, the selection of regularization parameters remains challenging. With regards to the above problems, the authors proposed a BLT reconstruction algorithm with an adaptive parameter choice rule. Methods: The proposed reconstruction algorithm uses a diffusion equation for modeling the bioluminescent photon transport. The diffusion equation is solved with a finite element method. Computed tomography (CT) images provide anatomical information regarding the geometry of the small animal and its internal organs. To reduce the ill-posedness of BLT, spectral information and the optimal permissible source region are employed. Then, the relationship between the unknown source distribution and multiview and multispectral boundary measurements is established based on the finite element method and the optimal permissible source region. Since the measured data are noisy, the BLT reconstruction is formulated as l{sub 2} data fidelity and a general regularization term. When choosing the regularization parameters for BLT, an efficient model function approach is proposed, which does not require knowledge of the noise level. This approach only requests the computation of the residual and regularized solution norm. With this knowledge, we construct the model function to approximate the objective function, and the regularization parameter is updated iteratively. Results: First, the micro-CT based mouse phantom was used for simulation verification. Simulation experiments were used to illustrate why multispectral data were used

  3. CHOICE OF PROTON DRIVER PARAMETERS FOR A NEUTRINO FACTORY.

    SciTech Connect

    KIRK, H.G.; BERG, J.S.; FERNOW, R.C.; GALLARDO, J.C.; SIMOS, N.; WENG, W.

    2006-06-23

    We discuss criteria for designing an optimal ''green field'' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power.

  4. Choice.

    PubMed

    Greenberg, Jay

    2008-09-01

    Understanding how and why analysands make the choices they do is central to both the clinical and the theoretical projects of psychoanalysis. And yet we know very little about the process of choice or about the relationship between choices and motives. A striking parallel is to be found between the ways choice is narrated in ancient Greek texts and the experience of analysts as they observe patients making choices in everyday clinical work. Pursuing this convergence of classical and contemporary sensibilities will illuminate crucial elements of the various meanings of choice, and of the way that these meanings change over the course of psychoanalytic treatment.

  5. Choice of Proton Driver Parameters for a Neutrino Factory

    SciTech Connect

    Kirk,H.G.; Berg, J. S.; Fernow, R. C.; Gallardo, J. C.; Simos, N.; Weng, W.-T.; Brooks, S.

    2006-06-26

    We discuss criteria for designing an optimal 'green field' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power. A neutrino factory may be the best experimental tool to unravel the physics involved in neutrino oscillation and CP violation phenomena [1]. To have sufficient neutrino flux for acceptable physics results within 5 years requires about 10{sup 22} protons on target per year, which corresponds to 1-4 MW of proton beam power from the proton driver depending on the beam energy. In the past, there were individual proposals from different laboratories of a particular design of proton driver capable of delivering beam power from 2 to 4 MW, without consistent attention paid to the needs or requirements from the downstream systems. In this study, we try to identify the requirements from those down stream systems first, then see whether it is possible to design a proton driver to meet those needs. Such a study will also assist site specific proposals to further improve on their designs to better serve the need of a proton driver for neutrino factory applications.

  6. Empirical estimation of consistency parameter in intertemporal choice based on Tsallis’ statistics

    NASA Astrophysics Data System (ADS)

    Takahashi, Taiki; Oono, Hidemi; Radford, Mark H. B.

    2007-07-01

    Impulsivity and inconsistency in intertemporal choice have been attracting attention in econophysics and neuroeconomics. Although loss of self-control by substance abusers is strongly related to their inconsistency in intertemporal choice, researchers in neuroeconomics and psychopharmacology have usually studied impulsivity in intertemporal choice using a discount rate (e.g. hyperbolic k), with little effort being expended on parameterizing subject's inconsistency in intertemporal choice. Recent studies using Tsallis’ statistics-based econophysics have found a discount function (i.e. q-exponential discount function), which may continuously parameterize a subject's consistency in intertemporal choice. In order to examine the usefulness of the consistency parameter (0⩽q⩽1) in the q-exponential discounting function in behavioral studies, we experimentally estimated the consistency parameter q in Tsallis’ statistics-based discounting function by assessing the points of subjective equality (indifference points) at seven delays (1 week-25 years) in humans (N=24). We observed that most (N=19) subjects’ intertemporal choice was completely inconsistent ( q=0, i.e. hyperbolic discounting), the mean consistency (0⩽q⩽1) was smaller than 0.5, and only one subject had a completely consistent intertemporal choice ( q=1, i.e. exponential discounting). There was no significant correlation between impulsivity and inconsistency parameters. Our results indicate that individual differences in consistency in intertemporal choice can be parameterized by introducing a q-exponential discount function and most people discount delayed rewards hyperbolically, rather than exponentially (i.e. mean q is smaller than 0.5). Further, impulsivity and inconsistency in intertemporal choice can be considered as separate behavioral tendencies. The usefulness of the consistency parameter q in psychopharmacological studies of addictive behavior was demonstrated in the present study.

  7. Time Required to Compute A Posteriori Probabilities,

    DTIC Science & Technology

    The paper discusses the time required to compute a posteriori probabilities using Bayes ’ Theorem . In a two-hypothesis example it is shown that, to... Bayes ’ Theorem as the group operation. Winograd’s results concerning the lower bound on the time required to perform a group operation on a finite group using logical circuitry are therefore applicable. (Author)

  8. Influence of choice of null network on small-world parameters of structural correlation networks.

    PubMed

    Hosseini, S M Hadi; Kesler, Shelli R

    2013-01-01

    In recent years, coordinated variations in brain morphology (e.g., volume, thickness) have been employed as a measure of structural association between brain regions to infer large-scale structural correlation networks. Recent evidence suggests that brain networks constructed in this manner are inherently more clustered than random networks of the same size and degree. Thus, null networks constructed by randomizing topology are not a good choice for benchmarking small-world parameters of these networks. In the present report, we investigated the influence of choice of null networks on small-world parameters of gray matter correlation networks in healthy individuals and survivors of acute lymphoblastic leukemia. Three types of null networks were studied: 1) networks constructed by topology randomization (TOP), 2) networks matched to the distributional properties of the observed covariance matrix (HQS), and 3) networks generated from correlation of randomized input data (COR). The results revealed that the choice of null network not only influences the estimated small-world parameters, it also influences the results of between-group differences in small-world parameters. In addition, at higher network densities, the choice of null network influences the direction of group differences in network measures. Our data suggest that the choice of null network is quite crucial for interpretation of group differences in small-world parameters of structural correlation networks. We argue that none of the available null models is perfect for estimation of small-world parameters for correlation networks and the relative strengths and weaknesses of the selected model should be carefully considered with respect to obtained network measures.

  9. Maximum a posteriori decoder for digital communications

    NASA Technical Reports Server (NTRS)

    Altes, Richard A. (Inventor)

    1997-01-01

    A system and method for decoding by identification of the most likely phase coded signal corresponding to received data. The present invention has particular application to communication with signals that experience spurious random phase perturbations. The generalized estimator-correlator uses a maximum a posteriori (MAP) estimator to generate phase estimates for correlation with incoming data samples and for correlation with mean phases indicative of unique hypothesized signals. The result is a MAP likelihood statistic for each hypothesized transmission, wherein the highest value statistic identifies the transmitted signal.

  10. A posteriori error estimates for Maxwell equations

    NASA Astrophysics Data System (ADS)

    Schoeberl, Joachim

    2008-06-01

    Maxwell equations are posed as variational boundary value problems in the function space H(operatorname{curl}) and are discretized by Nedelec finite elements. In Beck et al., 2000, a residual type a posteriori error estimator was proposed and analyzed under certain conditions onto the domain. In the present paper, we prove the reliability of that error estimator on Lipschitz domains. The key is to establish new error estimates for the commuting quasi-interpolation operators recently introduced in J. Schoeberl, Commuting quasi-interpolation operators for mixed finite elements. Similar estimates are required for additive Schwarz preconditioning. To incorporate boundary conditions, we establish a new extension result.

  11. On the choice of GARCH parameters for efficient modelling of real stock price dynamics

    NASA Astrophysics Data System (ADS)

    Pokhilchuk, K. A.; Savel'ev, S. E.

    2016-04-01

    We propose two different methods for optimal choice of GARCH(1,1) parameters for the efficient modelling of stock prices by using a particular return series. Using (as an example) stock return data for Intel Corporation, we vary parameters to fit the average volatility as well as fourth (linked to kurtosis of data) and eighth statistical moments and observe pure convergence of our simulated eighth moment to the stock data. Results indicate that fitting higher-order moments of a return series might not be an optimal approach for choosing GARCH parameters. In contrast, the simulated exponent of the Fourier spectrum decay is much less noisy and can easily fit the corresponding decay of the empirical Fourier spectrum of the used return series of Intel stock, allowing us to efficiently define all GARCH parameters. We compare the estimates of GARCH parameters obtained by fitting price data Fourier spectra with the ones obtained from standard software packages and conclude that the obtained estimates here are deeper in the stability region of parameters. Thus, the proposed method of using Fourier spectra of stock data to estimate GARCH parameters results in a more robust and stable stochastic process but with a shorter characteristic autocovariance time.

  12. An Anisotropic A posteriori Error Estimator for CFD

    NASA Astrophysics Data System (ADS)

    Feijóo, Raúl A.; Padra, Claudio; Quintana, Fernando

    In this article, a robust anisotropic adaptive algorithm is presented, to solve compressible-flow equations using a stabilized CFD solver and automatic mesh generators. The association includes a mesh generator, a flow solver, and an a posteriori error-estimator code. The estimator was selected among several choices available (Almeida et al. (2000). Comput. Methods Appl. Mech. Engng, 182, 379-400; Borges et al. (1998). "Computational mechanics: new trends and applications". Proceedings of the 4th World Congress on Computational Mechanics, Bs.As., Argentina) giving a powerful computational tool. The main aim is to capture solution discontinuities, in this case, shocks, using the least amount of computational resources, i.e. elements, compatible with a solution of good quality. This leads to high aspect-ratio elements (stretching). To achieve this, a directional error estimator was specifically selected. The numerical results show good behavior of the error estimator, resulting in strongly-adapted meshes in few steps, typically three or four iterations, enough to capture shocks using a moderate and well-distributed amount of elements.

  13. Order of Search in Fuzzy ART and Fuzzy ARTMAP: Effect of the Choice Parameter.

    PubMed

    Heileman, Gregory L.; Bebis, George; Fernlund, Hans; Georgiopoulos, Michael

    1996-12-01

    This paper focuses on two ART architectures, the Fuzzy ART and the Fuzzy ARTMAP. Fuzzy ART is a pattern clustering machine, while Fuzzy ARTMAP is a pattern classification machine. Our study concentrates on the order according to which categories in Fuzzy ART, or the ART(a) model of Fuzzy ARTMAP are chosen. Our work provides a geometrical, and clearer understanding of why, and in what order, these categories are chosen for various ranges of the choice parameter of the Fuzzy ART module. This understanding serves as a powerful tool in developing properties of learning pertaining to these neural network architectures; to strengthen this argument, it is worth mentioning that the order according to which categories are chosen in ART 1 and ARTMAP provided a valuable tool in proving important properties about these architectures. Copyright 1996 Elsevier Science Ltd.

  14. Parameters of rewards on choice behavior in Siamese fighting fish (Betta splendens).

    PubMed

    Shapiro, Martin S; Jensen, Ashley L

    2009-09-01

    Five experiments were conducted with Siamese fighting fish (Betta splendens) to investigate how choices in a T-maze were affected by parameters of a social reward (aggression display to another male): presence or absence, amount, delay and distance traveled. Bettas showed a preference for the side associated with the presence of another male rather than the side associated with nothing (Exp 1), a greater length of time of the reward (Exp 2) and shorter delay (Exp 3). The animals were indifferent when one side offered a longer delay to a longer reward time compared with a shorter delay to a shorter reward time (Exp 4). What was most surprising, however, was that fish preferred to choose the side that was associated with swimming a greater distance to reach an opponent male (Exp 5). These experiments demonstrate that, while some parameters of a visual reward affect behavior in predictable ways (greater amount, shorter delay), the complex motivations underlying inter-male aggression can produce what appear to be paradoxical results.

  15. Electron transport in magnetrons by a posteriori Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Costin, C.; Minea, T. M.; Popa, G.

    2014-02-01

    Electron transport across magnetic barriers is crucial in all magnetized plasmas. It governs not only the plasma parameters in the volume, but also the fluxes of charged particles towards the electrodes and walls. It is particularly important in high-power impulse magnetron sputtering (HiPIMS) reactors, influencing the quality of the deposited thin films, since this type of discharge is characterized by an increased ionization fraction of the sputtered material. Transport coefficients of electron clouds released both from the cathode and from several locations in the discharge volume are calculated for a HiPIMS discharge with pre-ionization operated in argon at 0.67 Pa and for very short pulses (few µs) using the a posteriori Monte Carlo simulation technique. For this type of discharge electron transport is characterized by strong temporal and spatial dependence. Both drift velocity and diffusion coefficient depend on the releasing position of the electron cloud. They exhibit minimum values at the centre of the race-track for the secondary electrons released from the cathode. The diffusion coefficient of the same electrons increases from 2 to 4 times when the cathode voltage is doubled, in the first 1.5 µs of the pulse. These parameters are discussed with respect to empirical Bohm diffusion.

  16. Superconvergence and recovery type a posteriori error estimation for hybrid stress finite element method

    NASA Astrophysics Data System (ADS)

    Bai, YanHong; Wu, YongKe; Xie, XiaoPing

    2016-09-01

    Superconvergence and a posteriori error estimators of recovery type are analyzed for the 4-node hybrid stress quadrilateral finite element method proposed by Pian and Sumihara (Int. J. Numer. Meth. Engrg., 1984, 20: 1685-1695) for linear elasticity problems. Uniform superconvergence of order $O(h^{1+\\min\\{\\alpha,1\\}})$ with respect to the Lam\\'{e} constant $\\lambda$ is established for both the recovered gradients of the displacement vector and the stress tensor under a mesh assumption, where $\\alpha>0$ is a parameter characterizing the distortion of meshes from parallelograms to quadrilaterals. A posteriori error estimators based on the recovered quantities are shown to be asymptotically exact. Numerical experiments confirm the theoretical results.

  17. A model selection algorithm for a posteriori probability estimation with neural networks.

    PubMed

    Arribas, Juan Ignacio; Cid-Sueiro, Jesús

    2005-07-01

    This paper proposes a novel algorithm to jointly determine the structure and the parameters of a posteriori probability model based on neural networks (NNs). It makes use of well-known ideas of pruning, splitting, and merging neural components and takes advantage of the probabilistic interpretation of these components. The algorithm, so called a posteriori probability model selection (PPMS), is applied to an NN architecture called the generalized softmax perceptron (GSP) whose outputs can be understood as probabilities although results shown can be extended to more general network architectures. Learning rules are derived from the application of the expectation-maximization algorithm to the GSP-PPMS structure. Simulation results show the advantages of the proposed algorithm with respect to other schemes.

  18. Analysis of the geophysical data using a posteriori algorithms

    NASA Astrophysics Data System (ADS)

    Voskoboynikova, Gyulnara; Khairetdinov, Marat

    2016-04-01

    The problems of monitoring, prediction and prevention of extraordinary natural and technogenic events are priority of modern problems. These events include earthquakes, volcanic eruptions, the lunar-solar tides, landslides, falling celestial bodies, explosions utilized stockpiles of ammunition, numerous quarry explosion in open coal mines, provoking technogenic earthquakes. Monitoring is based on a number of successive stages, which include remote registration of the events responses, measurement of the main parameters as arrival times of seismic waves or the original waveforms. At the final stage the inverse problems associated with determining the geographic location and time of the registration event are solving. Therefore, improving the accuracy of the parameters estimation of the original records in the high noise is an important problem. As is known, the main measurement errors arise due to the influence of external noise, the difference between the real and model structures of the medium, imprecision of the time definition in the events epicenter, the instrumental errors. Therefore, posteriori algorithms more accurate in comparison with known algorithms are proposed and investigated. They are based on a combination of discrete optimization method and fractal approach for joint detection and estimation of the arrival times in the quasi-periodic waveforms sequence in problems of geophysical monitoring with improved accuracy. Existing today, alternative approaches to solving these problems does not provide the given accuracy. The proposed algorithms are considered for the tasks of vibration sounding of the Earth in times of lunar and solar tides, and for the problem of monitoring of the borehole seismic source location in trade drilling.

  19. A Posteriori Analysis for Hydrodynamic Simulations Using Adjoint Methodologies

    SciTech Connect

    Woodward, C S; Estep, D; Sandelin, J; Wang, H

    2009-02-26

    This report contains results of analysis done during an FY08 feasibility study investigating the use of adjoint methodologies for a posteriori error estimation for hydrodynamics simulations. We developed an approach to adjoint analysis for these systems through use of modified equations and viscosity solutions. Targeting first the 1D Burgers equation, we include a verification of the adjoint operator for the modified equation for the Lax-Friedrichs scheme, then derivations of an a posteriori error analysis for a finite difference scheme and a discontinuous Galerkin scheme applied to this problem. We include some numerical results showing the use of the error estimate. Lastly, we develop a computable a posteriori error estimate for the MAC scheme applied to stationary Navier-Stokes.

  20. A Two-Stage Algorithm for Origin-Destination Matrices Estimation Considering Dynamic Dispersion Parameter for Route Choice

    PubMed Central

    Wang, Yong; Ma, Xiaolei; Liu, Yong; Gong, Ke; Henricakson, Kristian C.; Xu, Maozeng; Wang, Yinhai

    2016-01-01

    This paper proposes a two-stage algorithm to simultaneously estimate origin-destination (OD) matrix, link choice proportion, and dispersion parameter using partial traffic counts in a congested network. A non-linear optimization model is developed which incorporates a dynamic dispersion parameter, followed by a two-stage algorithm in which Generalized Least Squares (GLS) estimation and a Stochastic User Equilibrium (SUE) assignment model are iteratively applied until the convergence is reached. To evaluate the performance of the algorithm, the proposed approach is implemented in a hypothetical network using input data with high error, and tested under a range of variation coefficients. The root mean squared error (RMSE) of the estimated OD demand and link flows are used to evaluate the model estimation results. The results indicate that the estimated dispersion parameter theta is insensitive to the choice of variation coefficients. The proposed approach is shown to outperform two established OD estimation methods and produce parameter estimates that are close to the ground truth. In addition, the proposed approach is applied to an empirical network in Seattle, WA to validate the robustness and practicality of this methodology. In summary, this study proposes and evaluates an innovative computational approach to accurately estimate OD matrices using link-level traffic flow data, and provides useful insight for optimal parameter selection in modeling travelers’ route choice behavior. PMID:26761209

  1. A Two-Stage Algorithm for Origin-Destination Matrices Estimation Considering Dynamic Dispersion Parameter for Route Choice.

    PubMed

    Wang, Yong; Ma, Xiaolei; Liu, Yong; Gong, Ke; Henrickson, Kristian C; Henricakson, Kristian C; Xu, Maozeng; Wang, Yinhai

    2016-01-01

    This paper proposes a two-stage algorithm to simultaneously estimate origin-destination (OD) matrix, link choice proportion, and dispersion parameter using partial traffic counts in a congested network. A non-linear optimization model is developed which incorporates a dynamic dispersion parameter, followed by a two-stage algorithm in which Generalized Least Squares (GLS) estimation and a Stochastic User Equilibrium (SUE) assignment model are iteratively applied until the convergence is reached. To evaluate the performance of the algorithm, the proposed approach is implemented in a hypothetical network using input data with high error, and tested under a range of variation coefficients. The root mean squared error (RMSE) of the estimated OD demand and link flows are used to evaluate the model estimation results. The results indicate that the estimated dispersion parameter theta is insensitive to the choice of variation coefficients. The proposed approach is shown to outperform two established OD estimation methods and produce parameter estimates that are close to the ground truth. In addition, the proposed approach is applied to an empirical network in Seattle, WA to validate the robustness and practicality of this methodology. In summary, this study proposes and evaluates an innovative computational approach to accurately estimate OD matrices using link-level traffic flow data, and provides useful insight for optimal parameter selection in modeling travelers' route choice behavior.

  2. Suitable parameter choice on quantitative morphology of A549 cell in epithelial–mesenchymal transition

    PubMed Central

    Ren, Zhou-Xin; Yu, Hai-Bin; Li, Jian-Sheng; Shen, Jun-Ling; Du, Wen-Sen

    2015-01-01

    Evaluation of morphological changes in cells is an integral part of study on epithelial to mesenchymal transition (EMT), however, only a few papers reported the changes in quantitative parameters and no article compared different parameters for demanding better parameters. In the study, the purpose was to investigate suitable parameters for quantitative evaluation of EMT morphological changes. A549 human lung adenocarcinoma cell line was selected for the study. Some cells were stimulated by transforming growth factor-β1 (TGF-β1) for EMT, and other cells were as control without TGF-β1 stimulation. Subsequently, cells were placed in phase contrast microscope and three arbitrary fields were captured and saved with a personal computer. Using the tools of Photoshop software, some cells in an image were selected, segmented out and exchanged into unique hue, and other part in the image was shifted into another unique hue. The cells were calculated with 29 morphological parameters by Image Pro Plus software. A parameter between cells with or without TGF-β1 stimulation was compared statistically and nine parameters were significantly different between them. Receiver operating characteristic curve (ROC curve) of a parameter was described with SPSS software and F-test was used to compare two areas under the curves (AUCs) in Excel. Among them, roundness and radius ratio were the most AUCs and were significant higher than the other parameters. The results provided a new method with quantitative assessment of cell morphology during EMT, and found out two parameters, roundness and radius ratio, as suitable for quantification. PMID:26182364

  3. Limitations of the rheological mucoadhesion method: the effect of the choice of conditions and the rheological synergism parameter.

    PubMed

    Hägerström, Helene; Edsman, Katarina

    2003-04-01

    This work demonstrates several limitations of the simple rheological method that is widely used to investigate mucoadhesion of polymer gels. We establish the importance of the choice of conditions and the synergism parameter for the results obtained in comparative studies. Dynamic rheological measurements were performed on gels based on four slightly different poly(acrylic acid) (Carbopol) polymers and their corresponding mixtures with porcine stomach mucin and bovine submaxillary gland mucin. The rationale for the comparison of the polymers had a large influence on the results obtained. The method does not give the same ranking order when two different comparison strategies are used. Moreover, we show that the results obtained are also sensitive to where in the 'rheological range' the comparison is made, e.g., at which value of G'. Positive values of the synergism parameters are, for example, only seen with weak gels. The choice of synergism parameter also has a bearing on the results obtained, and here we suggest a new refined relative parameter, the log ratio (log(G'(mix)/G'(p))). We also investigated the adhesion of the gel preparations to porcine nasal mucosa, using tensile strength measurements. Increased gel strength resulted in stronger adhesion, which is in contrast to the results from the rheological method, where the positive values of the synergism parameters were seen only with weak gels. On the basis of the limitations demonstrated and discussed, we recommend that the rheological method should not be used as a stand-alone method for the studying of mucoadhesive properties of polymer gels.

  4. The Impact of Escape Alternative Position Change in Multiple-Choice Test on the Psychometric Properties of a Test and Its Items Parameters

    ERIC Educational Resources Information Center

    Hamadneh, Iyad Mohammed

    2015-01-01

    This study aimed at investigating the impact changing of escape alternative position in multiple-choice test on the psychometric properties of a test and it's items parameters (difficulty, discrimination & guessing), and estimation of examinee ability. To achieve the study objectives, a 4-alternative multiple choice type achievement test…

  5. Sensitivity of Human Choice to Manipulations of Parameters of Positive and Negative Sound Reinforcement

    ERIC Educational Resources Information Center

    Lambert, Joseph M.

    2013-01-01

    The purpose of this study was to determine whether altering parameters of positive and negative reinforcement in identical ways could influence behavior maintained by each in different ways. Three undergraduate students participated in a series of assessments designed to identify preferred and aversive sounds with similar reinforcing values.…

  6. Maximum a posteriori probability estimation for localizing damage using ultrasonic guided waves

    NASA Astrophysics Data System (ADS)

    Flynn, Eric B.; Todd, Michael D.; Wilcox, Paul D.; Drinkwater, Bruce W.; Croxford, Anthony J.

    2011-04-01

    Presented is an approach to damage localization for guided wave structural health monitoring (GWSHM) in plate-like structures. In this mode of SHM, transducers excite and sense guided waves in order to detect and characterize the presence of damage. The premise of the presented localization approach is simple: use as the estimated damage location the point on the structure with the maximum a posteriori probability (MAP) of being the location of damage (i.e., the most probable location given a set of sensor measurements). This is accomplished by constructing a minimally-informed statistical model of the GWSHM process. Parameters of the model which are unknown, such as scattered wave amplitude, are assigned non-informative Bayesian prior distributions and averaged out of the a posteriori probability calculation. Using an ensemble of measurements from an instrumented plate with stiffening stringers, the performance of the MAP estimate is compared to that of what were found to be the two most effective previously reported algorithms. The MAP estimate proved superior in nearly all test cases and was particularly effective in localizing damage using very sparse arrays of as few as three transducers.

  7. Parameter choices for a muon recirculating linear accelerator from 5 to 63 GeV

    SciTech Connect

    Berg, J. S.

    2014-06-19

    A recirculating linear accelerator (RLA) has been proposed to accelerate muons from 5 to 63 GeV for a muon collider. It should be usable both for a Higgs factory and as a stage for a higher energy collider. First, the constraints due to the beam loading are computed. Next, an expression for the longitudinal emittance growth to lowest order in the longitudinal emittance is worked out. After finding the longitudinal expression, a simplified model that describes the arcs and their approximate expression for the time of flight dependence on energy in those arcs is found. Finally, these results are used to estimate the parameters required for the RLA arcs and the linac phase.

  8. Haloperidol, dynamics of choice, and the parameters of the matching law.

    PubMed

    Aparicio, Carlos F

    2007-06-01

    The idea that dopamine mediates the reinforcing effects of stimuli persists in the field of neurosciences. The present study shows that haloperidol, a dopamine antagonist, does not eliminate the reinforcing value of food reinforcers. The ratio of reinforcers changed seven times across two levers within sessions, modeling a dynamic environment. The magnitude of the reinforcer was manipulated independently of the reinforcer ratio. Four doses of intraperitoneal haloperidol were assessed over periods of 12 daily sessions. Haloperidol did not impair the discrimination that the rats established between rich and lean levers; the response distributions favored the lever associated with the higher probability of reinforcement and the larger pellets. The parameters of the generalized matching law (bias and sensitivity) were used to estimate effects of haloperidol upon the motor system and upon the rats' motivation for food reinforcers.

  9. Extracting volatility signal using maximum a posteriori estimation

    NASA Astrophysics Data System (ADS)

    Neto, David

    2016-11-01

    This paper outlines a methodology to estimate a denoised volatility signal for foreign exchange rates using a hidden Markov model (HMM). For this purpose a maximum a posteriori (MAP) estimation is performed. A double exponential prior is used for the state variable (the log-volatility) in order to allow sharp jumps in realizations and then log-returns marginal distributions with heavy tails. We consider two routes to choose the regularization and we compare our MAP estimate to realized volatility measure for three exchange rates.

  10. High speed e-beam writing for large area photonic nanostructures — a choice of parameters

    NASA Astrophysics Data System (ADS)

    Li, Kezheng; Li, Juntao; Reardon, Christopher; Schuster, Christian S.; Wang, Yue; Triggs, Graham J.; Damnik, Niklas; Müenchenberger, Jana; Wang, Xuehua; Martins, Emiliano R.; Krauss, Thomas F.

    2016-09-01

    Photonic nanostructures are used for many optical systems and applications. However, some high-end applications require the use of electron-beam lithography (EBL) to generate such nanostructures. An important technological bottleneck is the exposure time of the EBL systems, which can exceed 24 hours per 1 cm2. Here, we have developed a method based on a target function to systematically increase the writing speed of EBL. As an example, we use as the target function the fidelity of the Fourier Transform spectra of nanostructures that are designed for thin film light trapping applications, and optimize the full parameter space of the lithography process. Finally, we are able to reduce the exposure time by a factor of 5.5 without loss of photonic performance. We show that the performances of the fastest written structures are identical to the original ones within experimental error. As the target function can be varied according to different purposes, the method is also applicable to guided mode resonant grating and many other areas. These findings contribute to the advancement of EBL and point towards making the technology more attractive for commercial applications.

  11. High speed e-beam writing for large area photonic nanostructures — a choice of parameters

    PubMed Central

    Li, Kezheng; Li, Juntao; Reardon, Christopher; Schuster, Christian S.; Wang, Yue; Triggs, Graham J.; Damnik, Niklas; Müenchenberger, Jana; Wang, Xuehua; Martins, Emiliano R.; Krauss, Thomas F.

    2016-01-01

    Photonic nanostructures are used for many optical systems and applications. However, some high-end applications require the use of electron-beam lithography (EBL) to generate such nanostructures. An important technological bottleneck is the exposure time of the EBL systems, which can exceed 24 hours per 1 cm2. Here, we have developed a method based on a target function to systematically increase the writing speed of EBL. As an example, we use as the target function the fidelity of the Fourier Transform spectra of nanostructures that are designed for thin film light trapping applications, and optimize the full parameter space of the lithography process. Finally, we are able to reduce the exposure time by a factor of 5.5 without loss of photonic performance. We show that the performances of the fastest written structures are identical to the original ones within experimental error. As the target function can be varied according to different purposes, the method is also applicable to guided mode resonant grating and many other areas. These findings contribute to the advancement of EBL and point towards making the technology more attractive for commercial applications. PMID:27633902

  12. Effects of using a posteriori methods for the conservation of integral invariants. [for weather forecasting

    NASA Technical Reports Server (NTRS)

    Takacs, Lawrence L.

    1988-01-01

    The nature and effect of using a posteriori adjustments to nonconservative finite-difference schemes to enforce integral invariants of the corresponding analytic system are examined. The method of a posteriori integral constraint restoration is analyzed for the case of linear advection, and the harmonic response associated with the a posteriori adjustments is examined in detail. The conservative properties of the shallow water system are reviewed, and the constraint restoration algorithm applied to the shallow water equations are described. A comparison is made between forecasts obtained using implicit and a posteriori methods for the conservation of mass, energy, and potential enstrophy in the complete nonlinear shallow-water system.

  13. Testing the role of the Barbero-Immirzi parameter and the choice of connection in loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Achour, Jibril Ben; Geiller, Marc; Noui, Karim; Yu, Chao

    2015-05-01

    We study the role of the Barbero-Immirzi parameter γ and the choice of connection in the construction of (a symmetry-reduced version of) loop quantum gravity. We start with the four-dimensional Lorentzian Holst action that we reduce to three dimensions in a way that preserves the presence of γ . In the time gauge, the phase space of the resulting three-dimensional theory mimics exactly that of the four-dimensional one. Its quantization can be performed, and on the kinematical Hilbert space spanned by SU(2) spin network states the spectra of geometric operators are discrete and γ dependent. However, because of the three-dimensional nature of the theory, its SU(2) Ashtekar-Barbero Hamiltonian constraint can be traded for the flatness constraint of an s l (2 ,C ) connection, and we show that this latter has to satisfy a linear simplicitylike condition analogous to the one used in the construction of spin foam models. The physically relevant solution to this constraint singles out the noncompact subgroup SU(1, 1), which in turn leads to the disappearance of the Barbero-Immirzi parameter and to a continuous length spectrum, in agreement with what is expected from Lorentzian three-dimensional gravity.

  14. Comparison between three option, four option and five option multiple choice question tests for quality parameters: A randomized study

    PubMed Central

    Vegada, Bhavisha; Shukla, Apexa; Khilnani, Ajeetkumar; Charan, Jaykaran; Desai, Chetna

    2016-01-01

    Background: Most of the academic teachers use four or five options per item of multiple choice question (MCQ) test as formative and summative assessment. Optimal number of options in MCQ item is a matter of considerable debate among academic teachers of various educational fields. There is a scarcity of the published literature regarding the optimum number of option in each item of MCQ in the field of medical education. Objectives: To compare three options, four options, and five options MCQs test for the quality parameters – reliability, validity, item analysis, distracter analysis, and time analysis. Materials and Methods: Participants were 3rd semester M.B.B.S. students. Students were divided randomly into three groups. Each group was given one set of MCQ test out of three options, four options, and five option randomly. Following the marking of the multiple choice tests, the participants’ option selections were analyzed and comparisons were conducted of the mean marks, mean time, validity, reliability and facility value, discrimination index, point biserial value, distracter analysis of three different option formats. Results: Students score more (P = 0.000) and took less time (P = 0.009) for the completion of three options as compared to four options and five options groups. Facility value was more (P = 0.004) in three options group as compared to four and five options groups. There was no significant difference between three groups for the validity, reliability, and item discrimination. Nonfunctioning distracters were more in the four and five options group as compared to three option group. Conclusion: Assessment based on three option MCQs is can be preferred over four option and five option MCQs. PMID:27721545

  15. A posteriori operation detection in evolving software models

    PubMed Central

    Langer, Philip; Wimmer, Manuel; Brosch, Petra; Herrmannsdörfer, Markus; Seidl, Martina; Wieland, Konrad; Kappel, Gerti

    2013-01-01

    As every software artifact, also software models are subject to continuous evolution. The operations applied between two successive versions of a model are crucial for understanding its evolution. Generic approaches for detecting operations a posteriori identify atomic operations, but neglect composite operations, such as refactorings, which leads to cluttered difference reports. To tackle this limitation, we present an orthogonal extension of existing atomic operation detection approaches for detecting also composite operations. Our approach searches for occurrences of composite operations within a set of detected atomic operations in a post-processing manner. One major benefit is the reuse of specifications available for executing composite operations also for detecting applications of them. We evaluate the accuracy of the approach in a real-world case study and investigate the scalability of our implementation in an experiment. PMID:23471366

  16. Implicit a posteriori error estimates for the Maxwell equations

    NASA Astrophysics Data System (ADS)

    Izsak, Ferenc; Harutyunyan, Davit; van der Vegt, Jaap J. W.

    2008-09-01

    An implicit a posteriori error estimation technique is presented and analyzed for the numerical solution of the time-harmonic Maxwell equations using Nedelec edge elements. For this purpose we define a weak formulation for the error on each element and provide an efficient and accurate numerical solution technique to solve the error equations locally. We investigate the well-posedness of the error equations and also consider the related eigenvalue problem for cubic elements. Numerical results for both smooth and non-smooth problems, including a problem with reentrant corners, show that an accurate prediction is obtained for the local error, and in particular the error distribution, which provides essential information to control an adaptation process. The error estimation technique is also compared with existing methods and provides significantly sharper estimates for a number of reported test cases.

  17. Cost functions to estimate a posteriori probabilities in multiclass problems.

    PubMed

    Cid-Sueiro, J; Arribas, J I; Urbán-Muñoz, S; Figueiras-Vidal, A R

    1999-01-01

    The problem of designing cost functions to estimate a posteriori probabilities in multiclass problems is addressed in this paper. We establish necessary and sufficient conditions that these costs must satisfy in one-class one-output networks whose outputs are consistent with probability laws. We focus our attention on a particular subset of the corresponding cost functions; those which verify two usually interesting properties: symmetry and separability (well-known cost functions, such as the quadratic cost or the cross entropy are particular cases in this subset). Finally, we present a universal stochastic gradient learning rule for single-layer networks, in the sense of minimizing a general version of these cost functions for a wide family of nonlinear activation functions.

  18. A posteriori pointwise error estimates for the boundary element method

    SciTech Connect

    Paulino, G.H.; Gray, L.J.; Zarikian, V.

    1995-01-01

    This report presents a new approach for a posteriori pointwise error estimation in the boundary element method. The estimator relies upon the evaluation of hypersingular integral equations, and is therefore intrinsic to the boundary integral equation approach. This property allows some theoretical justification by mathematically correlating the exact and estimated errors. A methodology is developed for approximating the error on the boundary as well as in the interior of the domain. In the interior, error estimates for both the function and its derivatives (e.g. potential and interior gradients for potential problems, displacements and stresses for elasticity problems) are presented. Extensive computational experiments have been performed for the two dimensional Laplace equation on interior domains, employing Dirichlet and mixed boundary conditions. The results indicate that the error estimates successfully track the form of the exact error curve. Moreover, a reasonable estimate of the magnitude of the actual error is also obtained.

  19. 4D maximum a posteriori reconstruction in dynamic SPECT using a compartmental model-based prior.

    PubMed

    Kadrmas, D J; Gullberg, G T

    2001-05-01

    A 4D ordered-subsets maximum a posteriori (OSMAP) algorithm for dynamic SPECT is described which uses a temporal prior that constrains each voxel's behaviour in time to conform to a compartmental model. No a priori limitations on kinetic parameters are applied; rather, the parameter estimates evolve as the algorithm iterates to a solution. The estimated parameters and time-activity curves are used within the reconstruction algorithm to model changes in the activity distribution as the camera rotates, avoiding artefacts due to inconsistencies of data between projection views. This potentially allows for fewer, longer-duration scans to be used and may have implications for noise reduction. The algorithm was evaluated qualitatively using dynamic 99mTc-teboroxime SPECT scans in two patients, and quantitatively using a series of simulated phantom experiments. The OSMAP algorithm resulted in images with better myocardial uniformity and definition, gave time-activity curves with reduced noise variations, and provided wash-in parameter estimates with better accuracy and lower statistical uncertainty than those obtained from conventional ordered-subsets expectation-maximization (OSEM) processing followed by compartmental modelling. The new algorithm effectively removed the bias in k21 estimates due to inconsistent projections for sampling schedules as slow as 60 s per timeframe, but no improvement in wash-out parameter estimates was observed in this work. The proposed dynamic OSMAP algorithm provides a flexible framework which may benefit a variety of dynamic tomographic imaging applications.

  20. Enabling Predictive Simulation and UQ of Complex Multiphysics PDE Systems by the Development of Goal-Oriented Variational Sensitivity Analysis and A Posteriori Error Estimation Methods

    SciTech Connect

    Ginting, Victor

    2014-03-15

    it was demonstrated that a posteriori analyses in general and in particular one that uses adjoint methods can accurately and efficiently compute numerical error estimates and sensitivity for critical Quantities of Interest (QoIs) that depend on a large number of parameters. Activities include: analysis and implementation of several time integration techniques for solving system of ODEs as typically obtained from spatial discretization of PDE systems; multirate integration methods for ordinary differential equations; formulation and analysis of an iterative multi-discretization Galerkin finite element method for multi-scale reaction-diffusion equations; investigation of an inexpensive postprocessing technique to estimate the error of finite element solution of the second-order quasi-linear elliptic problems measured in some global metrics; investigation of an application of the residual-based a posteriori error estimates to symmetric interior penalty discontinuous Galerkin method for solving a class of second order quasi-linear elliptic problems; a posteriori analysis of explicit time integrations for system of linear ordinary differential equations; derivation of accurate a posteriori goal oriented error estimates for a user-defined quantity of interest for two classes of first and second order IMEX schemes for advection-diffusion-reaction problems; Postprocessing finite element solution; and A Bayesian Framework for Uncertain Quantification of Porous Media Flows.

  1. A posteriori registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment

    PubMed Central

    Chibinski, Ana Cláudia; Coelho, Ulisses; Wambier, Letícia Stadler; Zedebski, Rosário de Arruda Moura; de Moraes, Mari Eli Leonelli; de Moraes, Luiz Cesar

    2016-01-01

    Purpose This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. Materials and Methods A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the posttreatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. Results The mean EARR observed was 15.44±12.1 pixels (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. Conclusion A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment. PMID:27051635

  2. A Posteriori Finite Element Bounds for Sensitivity Derivatives of Partial-Differential-Equation Outputs. Revised

    NASA Technical Reports Server (NTRS)

    Lewis, Robert Michael; Patera, Anthony T.; Peraire, Jaume

    1998-01-01

    We present a Neumann-subproblem a posteriori finite element procedure for the efficient and accurate calculation of rigorous, 'constant-free' upper and lower bounds for sensitivity derivatives of functionals of the solutions of partial differential equations. The design motivation for sensitivity derivative error control is discussed; the a posteriori finite element procedure is described; the asymptotic bounding properties and computational complexity of the method are summarized; and illustrative numerical results are presented.

  3. Preconditioned Alternating Projection Algorithms for Maximum a Posteriori ECT Reconstruction

    PubMed Central

    Krol, Andrzej; Li, Si; Shen, Lixin; Xu, Yuesheng

    2012-01-01

    We propose a preconditioned alternating projection algorithm (PAPA) for solving the maximum a posteriori (MAP) emission computed tomography (ECT) reconstruction problem. Specifically, we formulate the reconstruction problem as a constrained convex optimization problem with the total variation (TV) regularization. We then characterize the solution of the constrained convex optimization problem and show that it satisfies a system of fixed-point equations defined in terms of two proximity operators raised from the convex functions that define the TV-norm and the constrain involved in the problem. The characterization (of the solution) via the proximity operators that define two projection operators naturally leads to an alternating projection algorithm for finding the solution. For efficient numerical computation, we introduce to the alternating projection algorithm a preconditioning matrix (the EM-preconditioner) for the dense system matrix involved in the optimization problem. We prove theoretically convergence of the preconditioned alternating projection algorithm. In numerical experiments, performance of our algorithms, with an appropriately selected preconditioning matrix, is compared with performance of the conventional MAP expectation-maximization (MAP-EM) algorithm with TV regularizer (EM-TV) and that of the recently developed nested EM-TV algorithm for ECT reconstruction. Based on the numerical experiments performed in this work, we observe that the alternating projection algorithm with the EM-preconditioner outperforms significantly the EM-TV in all aspects including the convergence speed, the noise in the reconstructed images and the image quality. It also outperforms the nested EM-TV in the convergence speed while providing comparable image quality. PMID:23271835

  4. A regularized parameter choice in regularization for a common solution of a finite system of ill-posed equations involving Lipschitz continuous and accretive mappings

    NASA Astrophysics Data System (ADS)

    Buong, Nguyen; Dung, Nguyen Dinh

    2014-03-01

    In this paper, we present a regularized parameter choice in a new regularization method of Browder-Tikhonov type, for finding a common solution of a finite system of ill-posed operator equations involving Lipschitz continuous and accretive mappings in a real reflexive and strictly convex Banach space with a uniformly Gateaux differentiate norm. An estimate for convergence rates of regularized solution is also established.

  5. Combined Uncertainty and A-Posteriori Error Bound Estimates for General CFD Calculations: Theory and Software Implementation

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.

    2014-01-01

    This workshop presentation discusses the design and implementation of numerical methods for the quantification of statistical uncertainty, including a-posteriori error bounds, for output quantities computed using CFD methods. Hydrodynamic realizations often contain numerical error arising from finite-dimensional approximation (e.g. numerical methods using grids, basis functions, particles) and statistical uncertainty arising from incomplete information and/or statistical characterization of model parameters and random fields. The first task at hand is to derive formal error bounds for statistics given realizations containing finite-dimensional numerical error [1]. The error in computed output statistics contains contributions from both realization error and the error resulting from the calculation of statistics integrals using a numerical method. A second task is to devise computable a-posteriori error bounds by numerically approximating all terms arising in the error bound estimates. For the same reason that CFD calculations including error bounds but omitting uncertainty modeling are only of limited value, CFD calculations including uncertainty modeling but omitting error bounds are only of limited value. To gain maximum value from CFD calculations, a general software package for uncertainty quantification with quantified error bounds has been developed at NASA. The package provides implementations for a suite of numerical methods used in uncertainty quantification: Dense tensorization basis methods [3] and a subscale recovery variant [1] for non-smooth data, Sparse tensorization methods[2] utilizing node-nested hierarchies, Sampling methods[4] for high-dimensional random variable spaces.

  6. An Analysis of a Finite Element Method for Convection-Diffusion Problems. Part II. A Posteriori Error Estimates and Adaptivity.

    DTIC Science & Technology

    1983-03-01

    AN ANALYSIS OF A FINITE ELEMENT METHOD FOR CONVECTION- DIFFUSION PROBLEMS PART II: A POSTERIORI ERROR ESTIMATES AND ADAPTIVITY by W. G. Szymczak Y 6a...PERIOD COVERED AN ANALYSIS OF A FINITE ELEMENT METHOD FOR final life of the contract CONVECTION- DIFFUSION PROBLEM S. Part II: A POSTERIORI ERROR ...Element Method for Convection- Diffusion Problems. Part II: A Posteriori Error Estimates and Adaptivity W. G. Szvmczak and I. Babu~ka# Laboratory for

  7. A posteriori information effects on culpability judgments from a cross-cultural perspective.

    PubMed

    Wan, Wendy W N; Chiu, Chi-Yue; Luk, Chung-Leung

    2005-10-01

    A posteriori information about the moral attributes of the victim of a crime can affect an observer's judgment on the culpability of the actor of the crime so that negative moral attributes of the victim will lead to a lower judgment of culpability. The authors found this effect of a posteriori information among 118 American and 123 Chinese participants, but the underlying mechanisms were different between the two cultural groups. The Americans considered the psychological state of the actor during the crime, whereas the Chinese considered the morality of the actor during the crime. The authors discussed these results in light of the respondents' implicit theories of morality.

  8. A-Posteriori Error Estimation for Hyperbolic Conservation Laws with Constraint

    NASA Technical Reports Server (NTRS)

    Barth, Timothy

    2004-01-01

    This lecture considers a-posteriori error estimates for the numerical solution of conservation laws with time invariant constraints such as those arising in magnetohydrodynamics (MHD) and gravitational physics. Using standard duality arguments, a-posteriori error estimates for the discontinuous Galerkin finite element method are then presented for MHD with solenoidal constraint. From these estimates, a procedure for adaptive discretization is outlined. A taxonomy of Green's functions for the linearized MHD operator is given which characterizes the domain of dependence for pointwise errors. The extension to other constrained systems such as the Einstein equations of gravitational physics are then considered. Finally, future directions and open problems are discussed.

  9. Segmenting pectoralis muscle on digital mammograms by a Markov random field-maximum a posteriori model

    PubMed Central

    Ge, Mei; Mainprize, James G.; Mawdsley, Gordon E.; Yaffe, Martin J.

    2014-01-01

    Abstract. Accurate and automatic segmentation of the pectoralis muscle is essential in many breast image processing procedures, for example, in the computation of volumetric breast density from digital mammograms. Its segmentation is a difficult task due to the heterogeneity of the region, neighborhood complexities, and shape variability. The segmentation is achieved by pixel classification through a Markov random field (MRF) image model. Using the image intensity feature as observable data and local spatial information as a priori, the posterior distribution is estimated in a stochastic process. With a variable potential component in the energy function, by the maximum a posteriori (MAP) estimate of the labeling image, given the image intensity feature which is assumed to follow a Gaussian distribution, we achieved convergence properties in an appropriate sense by Metropolis sampling the posterior distribution of the selected energy function. By proposing an adjustable spatial constraint, the MRF-MAP model is able to embody the shape requirement and provide the required flexibility for the model parameter fitting process. We demonstrate that accurate and robust segmentation can be achieved for the curving-triangle-shaped pectoralis muscle in the medio-lateral-oblique (MLO) view, and the semielliptic-shaped muscle in cranio-caudal (CC) view digital mammograms. The applicable mammograms can be either “For Processing” or “For Presentation” image formats. The algorithm was developed using 56 MLO-view and 79 CC-view FFDM “For Processing” images, and quantitatively evaluated against a random selection of 122 MLO-view and 173 CC-view FFDM images of both presentation intent types. PMID:26158068

  10. An Iterative Maximum a Posteriori Estimation of Proficiency Level to Detect Multiple Local Likelihood Maxima

    ERIC Educational Resources Information Center

    Magis, David; Raiche, Gilles

    2010-01-01

    In this article the authors focus on the issue of the nonuniqueness of the maximum likelihood (ML) estimator of proficiency level in item response theory (with special attention to logistic models). The usual maximum a posteriori (MAP) method offers a good alternative within that framework; however, this article highlights some drawbacks of its…

  11. Weighted Maximum-a-Posteriori Estimation in Tests Composed of Dichotomous and Polytomous Items

    ERIC Educational Resources Information Center

    Sun, Shan-Shan; Tao, Jian; Chang, Hua-Hua; Shi, Ning-Zhong

    2012-01-01

    For mixed-type tests composed of dichotomous and polytomous items, polytomous items often yield more information than dichotomous items. To reflect the difference between the two types of items and to improve the precision of ability estimation, an adaptive weighted maximum-a-posteriori (WMAP) estimation is proposed. To evaluate the performance of…

  12. [Correlations between colorimetric parameters of teeth, eyes and skin. Perspectives in the choice of tooth shade for complete denture].

    PubMed

    Seck, A; Guèye, M; Dieng, L; Mbodj, E B; Ndiaye, C; Seck, M T; Lo, A S; Ngom, P I

    2013-09-01

    Rehabilitation with complete denture include among other objectives, improvement of facial and dental esthetics. To these ends, the artificial teeth should mimic as far as possible, healthy and natural dentition. The main objective of this study was to investigate factors associated with tooth color among black African subjects. One hundred and two subjects (72 men and 30 women) were included in this investigation. The colorimetric parameters of their teeth as well as those of the conjunctiva of their eyes and skin were recorded from standardized photographs. Two software, Mesurim and Photoshop were used for that purpose. Univariate and linear regression analysis were run to assess the association between tooth color and the variables age, gender and colorimetric parameters of eyes and skin. It appears from the result of this study that tooth color was positively and significantly associated with age. Stepwise multiple regression analysis further revealed that tooth hue can be best predicted by a combination of skin complexion and brightness and eye lightness.

  13. Nonmarket valuation of water quality in a rural transition economy in Turkey applying an a posteriori bid design

    NASA Astrophysics Data System (ADS)

    Bederli Tümay, Aylin; Brouwer, Roy

    2007-05-01

    In this paper, we investigate the economic benefits associated with public investments in wastewater treatment in one of the special protected areas along Turkey's touristic Mediterranean coast, the Köyceǧiz-Dalyan watershed. The benefits, measured in terms of boatable, fishable, swimmable and drinkable water quality, are estimated using a public survey format following the contingent valuation (CV) method. The study presented here is the first of its kind in Turkey. The study's main objective is to assess public perception, understanding, and valuation of improved wastewater treatment facilities in the two largest population centers in the watershed, facing the same water pollution problems as a result of lack of appropriate wastewater treatment. We test the validity and reliability of the application of the CV methodology to this specific environmental problem in a rural transition economy and evaluate the transferability of the results within the watershed. In order to facilitate willingness to pay (WTP) value elicitation we apply a novel dichotomous choice procedure where bid design takes place a posteriori instead of a priori. The statistical efficiency of different bid vectors is evaluated in terms of the estimated welfare measures' mean square errors using Monte Carlo simulation. The robustness of bid function specification is analyzed through average WTP and standard deviation estimated using parametric and nonparametric methods.

  14. A posteriori error estimation for hp -adaptivity for fourth-order equations

    NASA Astrophysics Data System (ADS)

    Moore, Peter K.; Rangelova, Marina

    2010-04-01

    A posteriori error estimates developed to drive hp-adaptivity for second-order reaction-diffusion equations are extended to fourth-order equations. A C^1 hierarchical finite element basis is constructed from Hermite-Lobatto polynomials. A priori estimates of the error in several norms for both the interpolant and finite element solution are derived. In the latter case this requires a generalization of the well-known Aubin-Nitsche technique to time-dependent fourth-order equations. We show that the finite element solution and corresponding Hermite-Lobatto interpolant are asymptotically equivalent. A posteriori error estimators based on this equivalence for solutions at two orders are presented. Both are shown to be asymptotically exact on grids of uniform order. These estimators can be used to control various adaptive strategies. Computational results for linear steady-state and time-dependent equations corroborate the theory and demonstrate the effectiveness of the estimators in adaptive settings.

  15. Maximum a posteriori estimation of crystallographic phases in X-ray diffraction tomography

    PubMed Central

    Gürsoy, Doĝa; Biçer, Tekin; Almer, Jonathan D.; Kettimuthu, Raj; Stock, Stuart R.; De Carlo, Francesco

    2015-01-01

    A maximum a posteriori approach is proposed for X-ray diffraction tomography for reconstructing three-dimensional spatial distribution of crystallographic phases and orientations of polycrystalline materials. The approach maximizes the a posteriori density which includes a Poisson log-likelihood and an a priori term that reinforces expected solution properties such as smoothness or local continuity. The reconstruction method is validated with experimental data acquired from a section of the spinous process of a porcine vertebra collected at the 1-ID-C beamline of the Advanced Photon Source, at Argonne National Laboratory. The reconstruction results show significant improvement in the reduction of aliasing and streaking artefacts, and improved robustness to noise and undersampling compared to conventional analytical inversion approaches. The approach has the potential to reduce data acquisition times, and significantly improve beamtime efficiency. PMID:25939627

  16. A Posteriori Error Estimation for Discontinuous Galerkin Approximations of Hyperbolic Systems

    NASA Technical Reports Server (NTRS)

    Larson, Mats G.; Barth, Timothy J.

    1999-01-01

    This article considers a posteriori error estimation of specified functionals for first-order systems of conservation laws discretized using the discontinuous Galerkin (DG) finite element method. Using duality techniques, we derive exact error representation formulas for both linear and nonlinear functionals given an associated bilinear or nonlinear variational form. Weighted residual approximations of the exact error representation formula are then proposed and numerically evaluated for Ringleb flow, an exact solution of the 2-D Euler equations.

  17. [Experience with using mathematic model for evaluation of a posteriori occupational risk].

    PubMed

    Piktushanskaia, T E

    2009-01-01

    The author analyzed changes in occupational morbidity among workers of leading economic branches of Russian Federation, gave prognosis of occupational morbidity level for recent and distant future. The morbidity level is characterized by reliable decreasing trend--that is due to long decline in diagnostic rate of occupational diseases in periodic medical examinations. The author specified mathematic model to evaluate a posteriori occupational risk, based on materials concerning periodic medical examinations in coal miners.

  18. Explicit a posteriori error estimates for eigenvalue analysis of heterogeneous elastic structures.

    SciTech Connect

    Walsh, Timothy Francis; Reese, Garth M.; Hetmaniuk, Ulrich L.

    2005-07-01

    An a posteriori error estimator is developed for the eigenvalue analysis of three-dimensional heterogeneous elastic structures. It constitutes an extension of a well-known explicit estimator to heterogeneous structures. We prove that our estimates are independent of the variations in material properties and independent of the polynomial degree of finite elements. Finally, we study numerically the effectivity of this estimator on several model problems.

  19. A posteriori correction for source decay in 3D bioluminescent source localization using multiview measured data

    NASA Astrophysics Data System (ADS)

    Sun, Li; Wang, Pu; Tian, Jie; Liu, Dan; Wang, Ruifang

    2009-02-01

    As a novel optical molecular imaging technique, bioluminescence tomography (BLT) can be used to monitor the biological activities non-invasively at the cellular and molecular levels. In most of known BLT studies, however, the time variation of the bioluminescent source is neglected. It gives rise to the inconsistent views during the multiview continuous wave measurement. In other words, the real measured data from different measured views come from 'different' bioluminescent sources. It could bring large errors in bioluminescence reconstruction. In this paper, a posteriori correction strategy for adaptive FEM-based reconstruction is proposed and developed. The method helps to improve the source localization considering the bioluminescent energy variance during the multiview measurement. In the method, the correction for boundary signals by means of a posteriori correction strategy, which adopts the energy ratio of measured data in the overlapping domains between the adjacent measurements as the correcting factor, can eliminate the effect of the inconsistent views. Then the adaptive mesh refinement with a posteriori error estimation helps to improve the precision and efficiency of BLT reconstruction. In addition, a priori permissible source region selection based on the surface measured data further reduces the ill-posedness of BLT and enhances numerical stability. Finally, three-dimension numerical simulations using the heterogeneous phantom are performed. The numerically measured data is generated by Monte Carlo (MC) method which is known as the Gold standard and can avoid the inverse crime. The reconstructed result with correction shows more accuracy compared to that without correction.

  20. Consistent robust a posteriori error majorants for approximate solutions of diffusion-reaction equations

    NASA Astrophysics Data System (ADS)

    Korneev, V. G.

    2016-11-01

    Efficiency of the error control of numerical solutions of partial differential equations entirely depends on the two factors: accuracy of an a posteriori error majorant and the computational cost of its evaluation for some test function/vector-function plus the cost of the latter. In the paper consistency of an a posteriori bound implies that it is the same in the order with the respective unimprovable a priori bound. Therefore, it is the basic characteristic related to the first factor. The paper is dedicated to the elliptic diffusion-reaction equations. We present a guaranteed robust a posteriori error majorant effective at any nonnegative constant reaction coefficient (r.c.). For a wide range of finite element solutions on a quasiuniform meshes the majorant is consistent. For big values of r.c. the majorant coincides with the majorant of Aubin (1972), which, as it is known, for relatively small r.c. (< ch -2 ) is inconsistent and looses its sense at r.c. approaching zero. Our majorant improves also some other majorants derived for the Poisson and reaction-diffusion equations.

  1. A coordinate-invariant model for deforming geodetic networks: understanding rank deficiencies, non-estimability of parameters, and the effect of the choice of minimal constraints

    NASA Astrophysics Data System (ADS)

    Chatzinikos, Miltiadis; Dermanis, Athanasios

    2016-11-01

    By considering a deformable geodetic network, deforming in a linear-in-time mode, according to a coordinate-invariant model, it becomes possible to get an insight into the rank deficiency of the stacking procedure, which is the standard method for estimating initial station coordinates and constant velocities, from coordinate time series. Comparing any two out of the infinitely many least squares estimates of stacking unknowns (initial station coordinates, velocity components and transformation parameters for the reference system in each data epoch), it is proven that the two solutions differ only by a linear-in-time trend in the transformation parameters. These pass over to the initial coordinates (the constant term) and to the velocity estimates (the time coefficient part). While the difference in initial coordinates is equivalent to a change of the reference system at the initial epoch, the differences in velocity components do not comply with those predicted by the same change of reference system for all epochs. Consequently, the different velocity component estimates, obtained by introducing different sets of minimal constraints, correspond to physically different station velocities, which are therefore non-estimable quantities. The theoretical findings are numerically verified for a global, a regional and a local network, by obtaining solutions based on four different types of minimal constraints, three usual algebraic ones (inner or partial inner) and the lately introduced kinematic constraints. Finally, by resorting to the basic ideas of Felix Tisserand, it is explained why the station velocities are non-estimable quantities in a very natural way. The problem of the optimal choice of minimal constraints and, hence, of the corresponding spatio-temporal reference system is shortly discussed.

  2. A coordinate-invariant model for deforming geodetic networks: understanding rank deficiencies, non-estimability of parameters, and the effect of the choice of minimal constraints

    NASA Astrophysics Data System (ADS)

    Chatzinikos, Miltiadis; Dermanis, Athanasios

    2017-04-01

    By considering a deformable geodetic network, deforming in a linear-in-time mode, according to a coordinate-invariant model, it becomes possible to get an insight into the rank deficiency of the stacking procedure, which is the standard method for estimating initial station coordinates and constant velocities, from coordinate time series. Comparing any two out of the infinitely many least squares estimates of stacking unknowns (initial station coordinates, velocity components and transformation parameters for the reference system in each data epoch), it is proven that the two solutions differ only by a linear-in-time trend in the transformation parameters. These pass over to the initial coordinates (the constant term) and to the velocity estimates (the time coefficient part). While the difference in initial coordinates is equivalent to a change of the reference system at the initial epoch, the differences in velocity components do not comply with those predicted by the same change of reference system for all epochs. Consequently, the different velocity component estimates, obtained by introducing different sets of minimal constraints, correspond to physically different station velocities, which are therefore non-estimable quantities. The theoretical findings are numerically verified for a global, a regional and a local network, by obtaining solutions based on four different types of minimal constraints, three usual algebraic ones (inner or partial inner) and the lately introduced kinematic constraints. Finally, by resorting to the basic ideas of Felix Tisserand, it is explained why the station velocities are non-estimable quantities in a very natural way. The problem of the optimal choice of minimal constraints and, hence, of the corresponding spatio-temporal reference system is shortly discussed.

  3. Quantitative evaluation of efficiency of the methods for a posteriori filtration of the slip-rate time histories

    NASA Astrophysics Data System (ADS)

    Kristekova, M.; Galis, M.; Moczo, P.; Kristek, J.

    2012-04-01

    Simulated slip-rate time histories often are not free from spurious high-frequency oscillations. This is because the used spatial grid is not fine enough to properly discretize possibly broad-spectrum slip-rate and stress variations and the spatial breakdown zone of the propagating rupture. In order to reduce the oscillations some numerical modelers apply the artificial damping. An alternative way is the application of the adaptive smoothing algorithm (ASA, Galis et al. 2010). The other modelers, however, rely on the a posteriori filtration. If the oscillations do not affect (change) development and propagation of the rupture during simulations, it is possible to apply a posteriori filtration to reduce the oscillations. Often, however, the a posteriori filtration is a problematic trade-off between suppression of oscillations and distortion of a true slip rate. We present quantitative comparison of efficiency of several methods. We have analyzed slip-rate time histories simulated by the FEM-TSN method. Signals containing spurious high-frequency oscillations and signals after application of a posteriori filtering have been compared to the reference signal. The reference signal was created by application of a careful iterative and adjusted denoising of the slip rate simulated using the finest (technically possible) spatial grid. We performed extensive numerical simulations in order to test efficiency of a posteriori filtration for slip rates with different level and nature of spurious oscillations. We show that the time-frequency analysis and time-frequency misfit criteria (Kristekova et al. 2006, 2009) are suitable tools for evaluation of efficiency of a posteriori filtration methods and also clear indicators of possible distortions introduced by a posteriori filtration.

  4. A maximum a posteriori probability time-delay estimation for seismic signals

    NASA Astrophysics Data System (ADS)

    Carrier, A.; Got, J.-L.

    2014-09-01

    Cross-correlation and cross-spectral time delays often exhibit strong outliers due to ambiguities or cycle jumps in the correlation function. Their number increases when signal-to-noise, signal similarity or spectral bandwidth decreases. Such outliers heavily determine the time-delay probability density function and the results of further computations (e.g. double-difference location and tomography) using these time delays. In the present research we expressed cross-correlation as a function of the squared difference between signal amplitudes and show that they are closely related. We used this difference as a cost function whose minimum is reached when signals are aligned. Ambiguities may be removed in this function by using a priori information. We propose using the traveltime difference as a priori time-delay information. By modelling the probability density function of the traveltime difference by a Cauchy distribution and the probability density function of the data (differences of seismic signal amplitudes) by a Laplace distribution we were able to find explicitly the time-delay a posteriori probability density function. The location of the maximum of this a posteriori probability density function is the maximum a posteriori time-delay estimation for earthquake signals. Using this estimation to calculate time delays for earthquakes on the south flank of Kilauea statistically improved the cross-correlation time-delay estimation for these data and resulted in successful double-difference relocation for an increased number of earthquakes. This robust time-delay estimation improves the spatiotemporal resolution of seismicity rates in the south flank of Kilauea.

  5. Three-dimensional super-resolution structured illumination microscopy with maximum a posteriori probability image estimation.

    PubMed

    Lukeš, Tomáš; Křížek, Pavel; Švindrych, Zdeněk; Benda, Jakub; Ovesný, Martin; Fliegel, Karel; Klíma, Miloš; Hagen, Guy M

    2014-12-01

    We introduce and demonstrate a new high performance image reconstruction method for super-resolution structured illumination microscopy based on maximum a posteriori probability estimation (MAP-SIM). Imaging performance is demonstrated on a variety of fluorescent samples of different thickness, labeling density and noise levels. The method provides good suppression of out of focus light, improves spatial resolution, and allows reconstruction of both 2D and 3D images of cells even in the case of weak signals. The method can be used to process both optical sectioning and super-resolution structured illumination microscopy data to create high quality super-resolution images.

  6. Phylogenomics and a posteriori data partitioning resolve the Cretaceous angiosperm radiation Malpighiales.

    PubMed

    Xi, Zhenxiang; Ruhfel, Brad R; Schaefer, Hanno; Amorim, André M; Sugumaran, M; Wurdack, Kenneth J; Endress, Peter K; Matthews, Merran L; Stevens, Peter F; Mathews, Sarah; Davis, Charles C

    2012-10-23

    The angiosperm order Malpighiales includes ~16,000 species and constitutes up to 40% of the understory tree diversity in tropical rain forests. Despite remarkable progress in angiosperm systematics during the last 20 y, relationships within Malpighiales remain poorly resolved, possibly owing to its rapid rise during the mid-Cretaceous. Using phylogenomic approaches, including analyses of 82 plastid genes from 58 species, we identified 12 additional clades in Malpighiales and substantially increased resolution along the backbone. This greatly improved phylogeny revealed a dynamic history of shifts in net diversification rates across Malpighiales, with bursts of diversification noted in the Barbados cherries (Malpighiaceae), cocas (Erythroxylaceae), and passion flowers (Passifloraceae). We found that commonly used a priori approaches for partitioning concatenated data in maximum likelihood analyses, by gene or by codon position, performed poorly relative to the use of partitions identified a posteriori using a Bayesian mixture model. We also found better branch support in trees inferred from a taxon-rich, data-sparse matrix, which deeply sampled only the phylogenetically critical placeholders, than in trees inferred from a taxon-sparse matrix with little missing data. Although this matrix has more missing data, our a posteriori partitioning strategy reduced the possibility of producing multiple distinct but equally optimal topologies and increased phylogenetic decisiveness, compared with the strategy of partitioning by gene. These approaches are likely to help improve phylogenetic resolution in other poorly resolved major clades of angiosperms and to be more broadly useful in studies across the Tree of Life.

  7. Experimental delayed-choice entanglement swapping

    NASA Astrophysics Data System (ADS)

    Ma, Xiao-Song; Zotter, Stefan; Kofler, Johannes; Ursin, Rupert; Jennewein, Thomas; Brukner, Časlav; Zeilinger, Anton

    2012-06-01

    Motivated by the question of which kind of physical interactions and processes are needed for the production of quantum entanglement, Peres has put forward the radical idea of delayed-choice entanglement swapping. There, entanglement can be `produced a posteriori, after the entangled particles have been measured and may no longer exist'. Here, we report the realization of Peres's gedanken experiment. Using four photons, we can actively delay the choice of measurement--implemented through a high-speed tunable bipartite-state analyser and a quantum random-number generator--on two of the photons into the time-like future of the registration of the other two photons. This effectively projects the two already registered photons onto one of two mutually exclusive quantum states in which the photons are either entangled (quantum correlations) or separable (classical correlations). This can also be viewed as `quantum steering into the past'.

  8. A posteriori correction of camera characteristics from large image data sets.

    PubMed

    Afanasyev, Pavel; Ravelli, Raimond B G; Matadeen, Rishi; De Carlo, Sacha; van Duinen, Gijs; Alewijnse, Bart; Peters, Peter J; Abrahams, Jan-Pieter; Portugal, Rodrigo V; Schatz, Michael; van Heel, Marin

    2015-06-11

    Large datasets are emerging in many fields of image processing including: electron microscopy, light microscopy, medical X-ray imaging, astronomy, etc. Novel computer-controlled instrumentation facilitates the collection of very large datasets containing thousands of individual digital images. In single-particle cryogenic electron microscopy ("cryo-EM"), for example, large datasets are required for achieving quasi-atomic resolution structures of biological complexes. Based on the collected data alone, large datasets allow us to precisely determine the statistical properties of the imaging sensor on a pixel-by-pixel basis, independent of any "a priori" normalization routinely applied to the raw image data during collection ("flat field correction"). Our straightforward "a posteriori" correction yields clean linear images as can be verified by Fourier Ring Correlation (FRC), illustrating the statistical independence of the corrected images over all spatial frequencies. The image sensor characteristics can also be measured continuously and used for correcting upcoming images.

  9. Conjugate quasilinear Dirichlet and Neumann problems and a posteriori error bounds

    NASA Technical Reports Server (NTRS)

    Lavery, J. E.

    1976-01-01

    Quasilinear Dirichlet and Neumann problems on a rectangle D with boundary D prime are considered. Using these concepts, conjugate problems, that is, a pair of one Dirichlet and one Neumann problem, the minima of the energies of which add to zero, are introduced. From the concept of conjugate problems, two-sided bounds for the energy of the exact solution of any given Dirichlet or Neumann problem are constructed. These two-sided bounds for the energy at the exact solution are in turn used to obtain a posteriori error bounds for the norm of the difference of the approximate and exact solutions of the problem. These bounds do not involve the unknown exact solution and are easily constructed numerically.

  10. Anatomical labeling of the circle of willis using maximum a posteriori graph matching.

    PubMed

    Robben, David; Sunaert, Stefan; Thijs, Vincent; Wilms, Guy; Maes, Frederik; Suetens, Paul

    2013-01-01

    A new method for anatomically labeling the vasculature is presented and applied to the Circle of Willis. Our method converts the segmented vasculature into a graph that is matched with an annotated graph atlas in a maximum a posteriori (MAP) way. The MAP matching is formulated as a quadratic binary programming problem which can be solved efficiently. Unlike previous methods, our approach can handle non tree-like vasculature and large topological differences. The method is evaluated in a leave-one-out test on MRA of 30 subjects where it achieves a sensitivity of 93% and a specificity of 85% with an average error of 1.5 mm on matching bifurcations in the vascular graph.

  11. Maximum a posteriori video super-resolution using a new multichannel image prior.

    PubMed

    Belekos, Stefanos P; Galatsanos, Nikolaos P; Katsaggelos, Aggelos K

    2010-06-01

    Super-resolution (SR) is the term used to define the process of estimating a high-resolution (HR) image or a set of HR images from a set of low-resolution (LR) observations. In this paper we propose a class of SR algorithms based on the maximum a posteriori (MAP) framework. These algorithms utilize a new multichannel image prior model, along with the state-of-the-art single channel image prior and observation models. A hierarchical (two-level) Gaussian nonstationary version of the multichannel prior is also defined and utilized within the same framework. Numerical experiments comparing the proposed algorithms among themselves and with other algorithms in the literature, demonstrate the advantages of the adopted multichannel approach.

  12. Real-time maximum a-posteriori image reconstruction for fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Jabbar, Anwar A.; Dilipkumar, Shilpa; C K, Rasmi; Rajan, K.; Mondal, Partha P.

    2015-08-01

    Rapid reconstruction of multidimensional image is crucial for enabling real-time 3D fluorescence imaging. This becomes a key factor for imaging rapidly occurring events in the cellular environment. To facilitate real-time imaging, we have developed a graphics processing unit (GPU) based real-time maximum a-posteriori (MAP) image reconstruction system. The parallel processing capability of GPU device that consists of a large number of tiny processing cores and the adaptability of image reconstruction algorithm to parallel processing (that employ multiple independent computing modules called threads) results in high temporal resolution. Moreover, the proposed quadratic potential based MAP algorithm effectively deconvolves the images as well as suppresses the noise. The multi-node multi-threaded GPU and the Compute Unified Device Architecture (CUDA) efficiently execute the iterative image reconstruction algorithm that is ≈200-fold faster (for large dataset) when compared to existing CPU based systems.

  13. An a posteriori-driven adaptive Mixed High-Order method with application to electrostatics

    NASA Astrophysics Data System (ADS)

    Di Pietro, Daniele A.; Specogna, Ruben

    2016-12-01

    In this work we propose an adaptive version of the recently introduced Mixed High-Order method and showcase its performance on a comprehensive set of academic and industrial problems in computational electromagnetism. The latter include, in particular, the numerical modeling of comb-drive and MEMS devices. Mesh adaptation is driven by newly derived, residual-based error estimators. The resulting method has several advantageous features: It supports fairly general meshes, it enables arbitrary approximation orders, and has a moderate computational cost thanks to hybridization and static condensation. The a posteriori-driven mesh refinement is shown to significantly enhance the performance on problems featuring singular solutions, allowing to fully exploit the high-order of approximation.

  14. A posteriori compensation of the systematic error due to polynomial interpolation in digital image correlation

    NASA Astrophysics Data System (ADS)

    Baldi, Antonio; Bertolino, Filippo

    2013-10-01

    It is well known that displacement components estimated using digital image correlation are affected by a systematic error due to the polynomial interpolation required by the numerical algorithm. The magnitude of bias depends on the characteristics of the speckle pattern (i.e., the frequency content of the image), on the fractional part of displacements and on the type of polynomial used for intensity interpolation. In literature, B-Spline polynomials are pointed out as being able to introduce the smaller errors, whereas bilinear and cubic interpolants generally give the worst results. However, the small bias of B-Spline polynomials is partially counterbalanced by a somewhat larger execution time. We will try to improve the accuracy of lower order polynomials by a posteriori correcting their results so as to obtain a faster and more accurate analysis.

  15. A posteriori error estimates for the Johnson–Nédélec FEM–BEM coupling

    PubMed Central

    Aurada, M.; Feischl, M.; Karkulik, M.; Praetorius, D.

    2012-01-01

    Only very recently, Sayas [The validity of Johnson–Nédélec's BEM-FEM coupling on polygonal interfaces. SIAM J Numer Anal 2009;47:3451–63] proved that the Johnson–Nédélec one-equation approach from [On the coupling of boundary integral and finite element methods. Math Comput 1980;35:1063–79] provides a stable coupling of finite element method (FEM) and boundary element method (BEM). In our work, we now adapt the analytical results for different a posteriori error estimates developed for the symmetric FEM–BEM coupling to the Johnson–Nédélec coupling. More precisely, we analyze the weighted-residual error estimator, the two-level error estimator, and different versions of (h−h/2)-based error estimators. In numerical experiments, we use these estimators to steer h-adaptive algorithms, and compare the effectivity of the different approaches. PMID:22347772

  16. Variance Difference between Maximum Likelihood Estimation Method and Expected A Posteriori Estimation Method Viewed from Number of Test Items

    ERIC Educational Resources Information Center

    Mahmud, Jumailiyah; Sutikno, Muzayanah; Naga, Dali S.

    2016-01-01

    The aim of this study is to determine variance difference between maximum likelihood and expected A posteriori estimation methods viewed from number of test items of aptitude test. The variance presents an accuracy generated by both maximum likelihood and Bayes estimation methods. The test consists of three subtests, each with 40 multiple-choice…

  17. Safer Choice

    EPA Pesticide Factsheets

    Safer Choice is a voluntary program that works to advance the mission of EPA to protect human health and the environment by helping product manufacturers choose the safest chemical ingredients possible.

  18. Volcanic eruption source parameters from active and passive microwave sensors

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario; Marzano, Frank S.; Cimini, Domenico; Mereu, Luigi

    2016-04-01

    It is well known, in the volcanology community, that precise information of the source parameters characterising an eruption are of predominant interest for the initialization of the Volcanic Transport and Dispersion Models (VTDM). Source parameters of main interest would be the top altitude of the volcanic plume, the flux of the mass ejected at the emission source, which is strictly related to the cloud top altitude, the distribution of volcanic mass concentration along the vertical column as well as the duration of the eruption and the erupted volume. Usually, the combination of a-posteriori field and numerical studies allow constraining the eruption source parameters for a given volcanic event thus making possible the forecast of ash dispersion and deposition from future volcanic eruptions. So far, remote sensors working at visible and infrared channels (cameras and radiometers) have been mainly used to detect, track and provide estimates of the concentration content and the prevailing size of the particles propagating within the ash clouds up to several thousand of kilometres far from the source as well as track back, a-posteriori, the accuracy of the VATDM outputs thus testing the initial choice made for the source parameters. Acoustic wave (infrasound) and microwave fixed scan radar (voldorad) were also used to infer source parameters. In this work we want to put our attention on the role of sensors operating at microwave wavelengths as complementary tools for the real time estimations of source parameters. Microwaves can benefit of the operability during night and day and a relatively negligible sensitivity to the presence of clouds (non precipitating weather clouds) at the cost of a limited coverage and larger spatial resolution when compared with infrared sensors. Thanks to the aforementioned advantages, the products from microwaves sensors are expected to be sensible mostly to the whole path traversed along the tephra cloud making microwaves particularly

  19. Choice Matters.

    ERIC Educational Resources Information Center

    Hicks, Darcy

    2001-01-01

    Describes how the author allows the children to make choices about their art and writing, enabling them to make connections between their own lives and work. Suggests that educators need to provide doorways to the things that give students ideas: books, music, objects, pictures, smells, sounds, and textures. (SG)

  20. Project Choice.

    ERIC Educational Resources Information Center

    Ewing Marion Kauffman Foundation, Kansas City, MO.

    Project Choice was begun with the goal of increasing the number of inner-city students who graduate on time. Ewing M. Kauffman and his business and foundation associates designed and elected to test a model that used the promise of postsecondary education or training as the incentive to stay in school. This report details the evolution of Project…

  1. Phylogenetic assignment of Mycobacterium tuberculosis Beijing clinical isolates in Japan by maximum a posteriori estimation.

    PubMed

    Seto, Junji; Wada, Takayuki; Iwamoto, Tomotada; Tamaru, Aki; Maeda, Shinji; Yamamoto, Kaori; Hase, Atsushi; Murakami, Koichi; Maeda, Eriko; Oishi, Akira; Migita, Yuji; Yamamoto, Taro; Ahiko, Tadayuki

    2015-10-01

    Intra-species phylogeny of Mycobacterium tuberculosis has been regarded as a clue to estimate its potential risk to develop drug-resistance and various epidemiological tendencies. Genotypic characterization of variable number of tandem repeats (VNTR), a standard tool to ascertain transmission routes, has been improving as a public health effort, but determining phylogenetic information from those efforts alone is difficult. We present a platform based on maximum a posteriori (MAP) estimation to estimate phylogenetic information for M. tuberculosis clinical isolates from individual profiles of VNTR types. This study used 1245 M. tuberculosis clinical isolates obtained throughout Japan for construction of an MAP estimation formula. Two MAP estimation formulae, classification of Beijing family and other lineages, and classification of five Beijing sublineages (ST11/26, STK, ST3, and ST25/19 belonging to the ancient Beijing subfamily and modern Beijing subfamily), were created based on 24 loci VNTR (24Beijing-VNTR) profiles and phylogenetic information of the isolates. Recursive estimation based on the formulae showed high concordance with their authentic phylogeny by multi-locus sequence typing (MLST) of the isolates. The formulae might further support phylogenetic estimation of the Beijing lineage M. tuberculosis from the VNTR genotype with various geographic backgrounds. These results suggest that MAP estimation can function as a reliable probabilistic process to append phylogenetic information to VNTR genotypes of M. tuberculosis independently, which might improve the usage of genotyping data for control, understanding, prevention, and treatment of TB.

  2. On Evaluation of Recharge Model Uncertainty: a Priori and a Posteriori

    SciTech Connect

    Ming Ye; Karl Pohlmann; Jenny Chapman; David Shafer

    2006-01-30

    Hydrologic environments are open and complex, rendering them prone to multiple interpretations and mathematical descriptions. Hydrologic analyses typically rely on a single conceptual-mathematical model, which ignores conceptual model uncertainty and may result in bias in predictions and under-estimation of predictive uncertainty. This study is to assess conceptual model uncertainty residing in five recharge models developed to date by different researchers based on different theories for Nevada and Death Valley area, CA. A recently developed statistical method, Maximum Likelihood Bayesian Model Averaging (MLBMA), is utilized for this analysis. In a Bayesian framework, the recharge model uncertainty is assessed, a priori, using expert judgments collected through an expert elicitation in the form of prior probabilities of the models. The uncertainty is then evaluated, a posteriori, by updating the prior probabilities to estimate posterior model probability. The updating is conducted through maximum likelihood inverse modeling by calibrating the Death Valley Regional Flow System (DVRFS) model corresponding to each recharge model against observations of head and flow. Calibration results of DVRFS for the five recharge models are used to estimate three information criteria (AIC, BIC, and KIC) used to rank and discriminate these models. Posterior probabilities of the five recharge models, evaluated using KIC, are used as weights to average head predictions, which gives posterior mean and variance. The posterior quantities incorporate both parametric and conceptual model uncertainties.

  3. Finite Element A Posteriori Error Estimation for Heat Conduction. Degree awarded by George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Lang, Christapher G.; Bey, Kim S. (Technical Monitor)

    2002-01-01

    This research investigates residual-based a posteriori error estimates for finite element approximations of heat conduction in single-layer and multi-layered materials. The finite element approximation, based upon hierarchical modelling combined with p-version finite elements, is described with specific application to a two-dimensional, steady state, heat-conduction problem. Element error indicators are determined by solving an element equation for the error with the element residual as a source, and a global error estimate in the energy norm is computed by collecting the element contributions. Numerical results of the performance of the error estimate are presented by comparisons to the actual error. Two methods are discussed and compared for approximating the element boundary flux. The equilibrated flux method provides more accurate results for estimating the error than the average flux method. The error estimation is applied to multi-layered materials with a modification to the equilibrated flux method to approximate the discontinuous flux along a boundary at the material interfaces. A directional error indicator is developed which distinguishes between the hierarchical modeling error and the finite element error. Numerical results are presented for single-layered materials which show that the directional indicators accurately determine which contribution to the total error dominates.

  4. Enhancing adaptive sparse grid approximations and improving refinement strategies using adjoint-based a posteriori error estimates

    DOE PAGES

    Jakeman, J. D.; Wildey, T.

    2015-01-01

    In this paper we present an algorithm for adaptive sparse grid approximations of quantities of interest computed from discretized partial differential equations. We use adjoint-based a posteriori error estimates of the interpolation error in the sparse grid to enhance the sparse grid approximation and to drive adaptivity. We show that utilizing these error estimates provides significantly more accurate functional values for random samples of the sparse grid approximation. We also demonstrate that alternative refinement strategies based upon a posteriori error estimates can lead to further increases in accuracy in the approximation over traditional hierarchical surplus based strategies. Throughout this papermore » we also provide and test a framework for balancing the physical discretization error with the stochastic interpolation error of the enhanced sparse grid approximation.« less

  5. Enhancing adaptive sparse grid approximations and improving refinement strategies using adjoint-based a posteriori error estimates

    SciTech Connect

    Jakeman, J. D.; Wildey, T.

    2015-01-01

    In this paper we present an algorithm for adaptive sparse grid approximations of quantities of interest computed from discretized partial differential equations. We use adjoint-based a posteriori error estimates of the interpolation error in the sparse grid to enhance the sparse grid approximation and to drive adaptivity. We show that utilizing these error estimates provides significantly more accurate functional values for random samples of the sparse grid approximation. We also demonstrate that alternative refinement strategies based upon a posteriori error estimates can lead to further increases in accuracy in the approximation over traditional hierarchical surplus based strategies. Throughout this paper we also provide and test a framework for balancing the physical discretization error with the stochastic interpolation error of the enhanced sparse grid approximation.

  6. Noise stochastic corrected maximum a posteriori estimator for birefringence imaging using polarization-sensitive optical coherence tomography

    PubMed Central

    Kasaragod, Deepa; Makita, Shuichi; Hong, Young-Joo; Yasuno, Yoshiaki

    2017-01-01

    This paper presents a noise-stochastic corrected maximum a posteriori estimator for birefringence imaging using Jones matrix optical coherence tomography. The estimator described in this paper is based on the relationship between probability distribution functions of the measured birefringence and the effective signal to noise ratio (ESNR) as well as the true birefringence and the true ESNR. The Monte Carlo method is used to numerically describe this relationship and adaptive 2D kernel density estimation provides the likelihood for a posteriori estimation of the true birefringence. Improved estimation is shown for the new estimator with stochastic model of ESNR in comparison to the old estimator, both based on the Jones matrix noise model. A comparison with the mean estimator is also done. Numerical simulation validates the superiority of the new estimator. The superior performance of the new estimator was also shown by in vivo measurement of optic nerve head. PMID:28270974

  7. Determination of quantitative trait variants by concordance via application of the a posteriori granddaughter design to the U.S. Holstein population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experimental designs that exploit family information can provide substantial predictive power in quantitative trait variant discovery projects. Concordance between quantitative trait locus genotype as determined by the a posteriori granddaughter design and marker genotype was determined for 29 trai...

  8. A Posteriori Study of a DNS Database Describing Super critical Binary-Species Mixing

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Taskinoglu, Ezgi

    2012-01-01

    Currently, the modeling of supercritical-pressure flows through Large Eddy Simulation (LES) uses models derived for atmospheric-pressure flows. Those atmospheric-pressure flows do not exhibit the particularities of high densitygradient magnitude features observed both in experiments and simulations of supercritical-pressure flows in the case of two species mixing. To assess whether the current LES modeling is appropriate and if found not appropriate to propose higher-fidelity models, a LES a posteriori study has been conducted for a mixing layer that initially contains different species in the lower and upper streams, and where the initial pressure is larger than the critical pressure of either species. An initially-imposed vorticity perturbation promotes roll-up and a double pairing of four initial span-wise vortices into an ultimate vortex that reaches a transitional state. The LES equations consist of the differential conservation equations coupled with a real-gas equation of state, and the equation set uses transport properties depending on the thermodynamic variables. Unlike all LES models to date, the differential equations contain, additional to the subgrid scale (SGS) fluxes, a new SGS term that is a pressure correction in the momentum equation. This additional term results from filtering of Direct Numerical Simulation (DNS) equations, and represents the gradient of the difference between the filtered pressure and the pressure computed from the filtered flow field. A previous a priori analysis, using a DNS database for the same configuration, found this term to be of leading order in the momentum equation, a fact traced to the existence of high-densitygradient magnitude regions that populated the entire flow; in the study, models were proposed for the SGS fluxes as well as this new term. In the present study, the previously proposed constantcoefficient SGS-flux models of the a priori investigation are tested a posteriori in LES, devoid of or including, the

  9. Modelling of turbulent lifted jet flames using flamelets: a priori assessment and a posteriori validation

    NASA Astrophysics Data System (ADS)

    Ruan, Shaohong; Swaminathan, Nedunchezhian; Darbyshire, Oliver

    2014-03-01

    This study focuses on the modelling of turbulent lifted jet flames using flamelets and a presumed Probability Density Function (PDF) approach with interest in both flame lift-off height and flame brush structure. First, flamelet models used to capture contributions from premixed and non-premixed modes of the partially premixed combustion in the lifted jet flame are assessed using a Direct Numerical Simulation (DNS) data for a turbulent lifted hydrogen jet flame. The joint PDFs of mixture fraction Z and progress variable c, including their statistical correlation, are obtained using a copula method, which is also validated using the DNS data. The statistically independent PDFs are found to be generally inadequate to represent the joint PDFs from the DNS data. The effects of Z-c correlation and the contribution from the non-premixed combustion mode on the flame lift-off height are studied systematically by including one effect at a time in the simulations used for a posteriori validation. A simple model including the effects of chemical kinetics and scalar dissipation rate is suggested and used for non-premixed combustion contributions. The results clearly show that both Z-c correlation and non-premixed combustion effects are required in the premixed flamelets approach to get good agreement with the measured flame lift-off heights as a function of jet velocity. The flame brush structure reported in earlier experimental studies is also captured reasonably well for various axial positions. It seems that flame stabilisation is influenced by both premixed and non-premixed combustion modes, and their mutual influences.

  10. Hard choices.

    PubMed

    Furedi, A

    1999-01-01

    The cultural discourse that frames the abortion debate has changed and become more complex over the years. To date, concerns about the need to defend the choice have shifted to moral and ethical issues surrounding abortion. The right of women to abortion can be situated in the context of ethical principles, which are basic to what we hold valuable in the modern society. The ethical principle of "procreative autonomy", the right of humans to control their own role in procreation has an unusually significant place in modern political culture in which human dignity was an important feature. Central to human dignity was the principle that "people possess the moral right and responsibility to answer the basic questions about the value and meaning of their own lives." Another crucial issue is the need to defend the "bodily autonomy" of women. Forcing women to support the fetus against her will flies against such principles as the need for voluntary consent to medical treatment. These arguments do not suggest for a moral indifference towards abortion choices, but as Ronald Dworkin argues, "tolerance is a cost we must pay for our adventure in liberty."

  11. Choice-Based Conjoint Analysis: Classification vs. Discrete Choice Models

    NASA Astrophysics Data System (ADS)

    Giesen, Joachim; Mueller, Klaus; Taneva, Bilyana; Zolliker, Peter

    Conjoint analysis is a family of techniques that originated in psychology and later became popular in market research. The main objective of conjoint analysis is to measure an individual's or a population's preferences on a class of options that can be described by parameters and their levels. We consider preference data obtained in choice-based conjoint analysis studies, where one observes test persons' choices on small subsets of the options. There are many ways to analyze choice-based conjoint analysis data. Here we discuss the intuition behind a classification based approach, and compare this approach to one based on statistical assumptions (discrete choice models) and to a regression approach. Our comparison on real and synthetic data indicates that the classification approach outperforms the discrete choice models.

  12. Effect of parameter choice in root water uptake models - the arrangement of root hydraulic properties within the root architecture affects dynamics and efficiency of root water uptake

    NASA Astrophysics Data System (ADS)

    Bechmann, M.; Schneider, C.; Carminati, A.; Vetterlein, D.; Attinger, S.; Hildebrandt, A.

    2014-10-01

    Detailed three-dimensional models of root water uptake have become increasingly popular for investigating the process of root water uptake. However, they suffer from a lack of information on important parameters, particularly on the spatial distribution of root axial and radial conductivities, which vary greatly along a root system. In this paper we explore how the arrangement of those root hydraulic properties and branching within the root system affects modelled uptake dynamics, xylem water potential and the efficiency of root water uptake. We first apply a simple model to illustrate the mechanisms at the scale of single roots. By using two efficiency indices based on (i) the collar xylem potential ("effort") and (ii) the integral amount of unstressed root water uptake ("water yield"), we show that an optimal root length emerges, depending on the ratio between roots axial and radial conductivity. Young roots with high capacity for radial uptake are only efficient when they are short. Branching, in combination with mature transport roots, enables soil exploration and substantially increases active young root length at low collar potentials. Second, we investigate how this shapes uptake dynamics at the plant scale using a comprehensive three-dimensional root water uptake model. Plant-scale dynamics, such as the average uptake depth of entire root systems, were only minimally influenced by the hydraulic parameterization. However, other factors such as hydraulic redistribution, collar potential, internal redistribution patterns and instantaneous uptake depth depended strongly on the arrangement on the arrangement of root hydraulic properties. Root systems were most efficient when assembled of different root types, allowing for separation of root function in uptake (numerous short apical young roots) and transport (longer mature roots). Modelling results became similar when this heterogeneity was accounted for to some degree (i.e. if the root systems contained between

  13. Blind deconvolution of images with model discrepancies using maximum a posteriori estimation with heavy-tailed priors

    NASA Astrophysics Data System (ADS)

    Kotera, Jan; Å roubek, Filip

    2015-02-01

    Single image blind deconvolution aims to estimate the unknown blur from a single observed blurred image and recover the original sharp image. Such task is severely ill-posed and typical approaches involve some heuristic or other steps without clear mathematical explanation to arrive at an acceptable solution. We show that a straight- forward maximum a posteriori estimation incorporating sparse priors and mechanism to deal with boundary artifacts, combined with an efficient numerical method can produce results which compete with or outperform much more complicated state-of-the-art methods. Our method is naturally extended to deal with overexposure in low-light photography, where linear blurring model is violated.

  14. Combined Uncertainty and A-Posteriori Error Bound Estimates for CFD Calculations: Theory and Implementation

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.

    2014-01-01

    Simulation codes often utilize finite-dimensional approximation resulting in numerical error. Some examples include, numerical methods utilizing grids and finite-dimensional basis functions, particle methods using a finite number of particles. These same simulation codes also often contain sources of uncertainty, for example, uncertain parameters and fields associated with the imposition of initial and boundary data,uncertain physical model parameters such as chemical reaction rates, mixture model parameters, material property parameters, etc.

  15. School Choice. IDRA Focus.

    ERIC Educational Resources Information Center

    Robledo Montecel, Maria, Ed.; Supik, Josie Danini, Ed.

    1994-01-01

    This newsletter contains five articles on the implications of school choice for minority and disadvantaged students. "School Choice: Choices for Whom? Promises and Panaceas," by Maria Robledo Montecel, discusses some major problems related to school choice and vouchers, particularly who would have the choice (families or schools), who…

  16. The psychopathology of choice.

    PubMed

    Headlee, R; Kalogjera, I J

    1988-10-01

    The important, often neglected factor of choice, learned in childhood, is examined in detail and illustrated by clinical examples. The primary etiological factors in psychopathology of choice are: (1) Too much choice allowed before integration is possible; (2) Too little choice allowed and (3) Distortions of choice due to racial, sexual, and religious prejudices or cognitive distortions.

  17. Allowing for MSD prevention during facilities planning for a public service: an a posteriori analysis of 10 library design projects.

    PubMed

    Bellemare, Marie; Trudel, Louis; Ledoux, Elise; Montreuil, Sylvie; Marier, Micheline; Laberge, Marie; Vincent, Patrick

    2006-01-01

    Research was conducted to identify an ergonomics-based intervention model designed to factor in musculoskeletal disorder (MSD) prevention when library projects are being designed. The first stage of the research involved an a posteriori analysis of 10 recent redesign projects. The purpose of the analysis was to document perceptions about the attention given to MSD prevention measures over the course of a project on the part of 2 categories of employees: librarians responsible for such projects and personnel working in the libraries before and after changes. Subjects were interviewed in focus groups. Outcomes of the analysis can guide our ergonomic assessment of current situations and contribute to a better understanding of the way inclusion or improvement of prevention measures can support the workplace design process.

  18. An a-posteriori error estimator for linear elastic fracture mechanics using the stable generalized/extended finite element method

    NASA Astrophysics Data System (ADS)

    Lins, R. M.; Ferreira, M. D. C.; Proença, S. P. B.; Duarte, C. A.

    2015-12-01

    In this study, a recovery-based a-posteriori error estimator originally proposed for the Corrected XFEM is investigated in the framework of the stable generalized FEM (SGFEM). Both Heaviside and branch functions are adopted to enrich the approximations in the SGFEM. Some necessary adjustments to adapt the expressions defining the enhanced stresses in the original error estimator are discussed in the SGFEM framework. Relevant aspects such as effectivity indexes, error distribution, convergence rates and accuracy of the recovered stresses are used in order to highlight the main findings and the effectiveness of the error estimator. Two benchmark problems of the 2-D fracture mechanics are selected to assess the robustness of the error estimator hereby investigated. The main findings of this investigation are: the SGFEM shows higher accuracy than G/XFEM and a reduced sensitivity to blending element issues. The error estimator can accurately capture these features of both methods.

  19. A Novel Gibbs Maximum A Posteriori (GMAP) Approach on Bayesian Nonlinear Mixed-Effects Population Pharmacokinetics (PK) Models

    PubMed Central

    Kim, Seongho; Hall, Stephen D.; Li, Lang

    2009-01-01

    In this paper, various Bayesian Monte Carlo Markov Chain (MCMC) methods and the proposed algorithm, Gibbs maximum a posteriori (GMAP) algorithm, are compared for implementing the nonlinear mixed-effects model in pharmacokinetics (PK) studies. An intravenous two-compartmental PK model is adopted to fit the PK data from the midazolam (MDZ) studies, which recruited 24 individuals with 9 different time points per subject. The three-stage hierarchical nonlinear mixed model is constructed. Data analysis and model performance comparisons show that GMAP converges the fastest, and provides reliable results. At the mean time, data augmentation (DA) methods are used for the Random-walk Metropolis method. Data analysis shows that the speed of the convergence of Random-walk Metropolis can be improved by DA, but all of them are not as fast as GMAP. The performance of GMAP and various MCMC algorithms are compared through Midazolam data analysis and simulation. PMID:20183435

  20. Reliable and efficient a posteriori error estimation for adaptive IGA boundary element methods for weakly-singular integral equations

    NASA Astrophysics Data System (ADS)

    Feischl, Michael; Gantner, Gregor; Praetorius, Dirk

    2015-06-01

    We consider the Galerkin boundary element method (BEM) for weakly-singular integral equations of the first-kind in 2D. We analyze some residual-type a posteriori error estimator which provides a lower as well as an upper bound for the unknown Galerkin BEM error. The required assumptions are weak and allow for piecewise smooth parametrizations of the boundary, local mesh-refinement, and related standard piecewise polynomials as well as NURBS. In particular, our analysis gives a first contribution to adaptive BEM in the frame of isogeometric analysis (IGABEM), for which we formulate an adaptive algorithm which steers the local mesh-refinement and the multiplicity of the knots. Numerical experiments underline the theoretical findings and show that the proposed adaptive strategy leads to optimal convergence.

  1. Reliable and efficient a posteriori error estimation for adaptive IGA boundary element methods for weakly-singular integral equations

    PubMed Central

    Feischl, Michael; Gantner, Gregor; Praetorius, Dirk

    2015-01-01

    We consider the Galerkin boundary element method (BEM) for weakly-singular integral equations of the first-kind in 2D. We analyze some residual-type a posteriori error estimator which provides a lower as well as an upper bound for the unknown Galerkin BEM error. The required assumptions are weak and allow for piecewise smooth parametrizations of the boundary, local mesh-refinement, and related standard piecewise polynomials as well as NURBS. In particular, our analysis gives a first contribution to adaptive BEM in the frame of isogeometric analysis (IGABEM), for which we formulate an adaptive algorithm which steers the local mesh-refinement and the multiplicity of the knots. Numerical experiments underline the theoretical findings and show that the proposed adaptive strategy leads to optimal convergence. PMID:26085698

  2. A Maximum a Posteriori Estimation Framework for Robust High Dynamic Range Video Synthesis

    NASA Astrophysics Data System (ADS)

    Li, Yuelong; Lee, Chul; Monga, Vishal

    2017-03-01

    High dynamic range (HDR) image synthesis from multiple low dynamic range (LDR) exposures continues to be actively researched. The extension to HDR video synthesis is a topic of significant current interest due to potential cost benefits. For HDR video, a stiff practical challenge presents itself in the form of accurate correspondence estimation of objects between video frames. In particular, loss of data resulting from poor exposures and varying intensity make conventional optical flow methods highly inaccurate. We avoid exact correspondence estimation by proposing a statistical approach via maximum a posterior (MAP) estimation, and under appropriate statistical assumptions and choice of priors and models, we reduce it to an optimization problem of solving for the foreground and background of the target frame. We obtain the background through rank minimization and estimate the foreground via a novel multiscale adaptive kernel regression technique, which implicitly captures local structure and temporal motion by solving an unconstrained optimization problem. Extensive experimental results on both real and synthetic datasets demonstrate that our algorithm is more capable of delivering high-quality HDR videos than current state-of-the-art methods, under both subjective and objective assessments. Furthermore, a thorough complexity analysis reveals that our algorithm achieves better complexity-performance trade-off than conventional methods.

  3. Choosing Choice: School Choice in International Perspective.

    ERIC Educational Resources Information Center

    Plank, David N., Ed.; Sykes, Gary, Ed.

    The chapters in this book originated as papers for a conference, School Choice and Educational Change, held in March 2000 at Michigan State University. An introductory chapter provides a comparative analysis of the lessons learned from international experience with school-choice policies, based on a review of case studies in several countries. The…

  4. A Priori and a Posteriori Dietary Patterns during Pregnancy and Gestational Weight Gain: The Generation R Study.

    PubMed

    Tielemans, Myrte J; Erler, Nicole S; Leermakers, Elisabeth T M; van den Broek, Marion; Jaddoe, Vincent W V; Steegers, Eric A P; Kiefte-de Jong, Jessica C; Franco, Oscar H

    2015-11-12

    Abnormal gestational weight gain (GWG) is associated with adverse pregnancy outcomes. We examined whether dietary patterns are associated with GWG. Participants included 3374 pregnant women from a population-based cohort in the Netherlands. Dietary intake during pregnancy was assessed with food-frequency questionnaires. Three a posteriori-derived dietary patterns were identified using principal component analysis: a "Vegetable, oil and fish", a "Nuts, high-fiber cereals and soy", and a "Margarine, sugar and snacks" pattern. The a priori-defined dietary pattern was based on national dietary recommendations. Weight was repeatedly measured around 13, 20 and 30 weeks of pregnancy; pre-pregnancy and maximum weight were self-reported. Normal weight women with high adherence to the "Vegetable, oil and fish" pattern had higher early-pregnancy GWG than those with low adherence (43 g/week (95% CI 16; 69) for highest vs. lowest quartile (Q)). Adherence to the "Margarine, sugar and snacks" pattern was associated with a higher prevalence of excessive GWG (OR 1.45 (95% CI 1.06; 1.99) Q4 vs. Q1). Normal weight women with higher scores on the "Nuts, high-fiber cereals and soy" pattern had more moderate GWG than women with lower scores (-0.01 (95% CI -0.02; -0.00) per SD). The a priori-defined pattern was not associated with GWG. To conclude, specific dietary patterns may play a role in early pregnancy but are not consistently associated with GWG.

  5. Privatization and Educational Choice.

    ERIC Educational Resources Information Center

    Lieberman, Myron

    This book describes how and why educational choice movements will affect public education. It uses a public-choice approach to argue that both the supporters and opponents of private and school choice have failed to address several critical issues. Following an introductory chapter, chapter 2 is devoted to the rationale for contracting out…

  6. A posteriori testing of algebraic flame surface density models for LES

    NASA Astrophysics Data System (ADS)

    Ma, T.; Stein, O. T.; Chakraborty, N.; Kempf, A. M.

    2013-06-01

    In the application of Large Eddy Simulation (LES) to premixed combustion, the unknown filtered chemical source term can be modelled by the generalised flame surface density (FSD) using algebraic models for the wrinkling factor Ξ. The present study compares the behaviour of the various models by first examining the effect of sub-grid turbulent velocity fluctuation on Ξ through a one-dimensional analysis and by the LES of the ORACLES burner (Nguyen, Bruel, and Reichstadt, Flow, Turbulence and Combustion Vol. 82 [2009], pp. 155-183) and the Volvo Rig (Sjunnesson, Nelsson, and Max, Laser Anemometry, Vol. 3 [1991], pp. 83-90; Sjunnesson, Henrikson, and Löfström, AIAA Journal, Vol. 28 [1992], pp. AIAA-92-3650). Several sensitivity studies on parameters such as the turbulent viscosity and the grid resolution are also carried out. A statistically 1-D analysis of turbulent flame propagation reveals that counter gradient transport of the progress variable needs to be accounted for to obtain a realistic flame thickness from the simulations using algebraic FSD based closure. The two burner setups are found to operate mainly within the wrinkling/corrugated flamelet regime based on the premixed combustion diagram for LES (Pitsch and Duchamp de Lageneste, Proceedings of the Combustion Institute, Vol. 29 [2002], pp. 2001-2008) and this suggests that the models are operating within their ideal range. The performance of the algebraic models are then assessed by comparing velocity statistics, followed by a detailed error analysis for the ORACLES burner. Four of the tested models were found to perform reasonably well against experiments, and one of these four further excels in being the most grid-independent. For the Volvo Rig, more focus is placed upon the comparison of temperature data and identifying changes in flame structure amongst the different models. It is found that the few models which largely over-predict velocities in the ORACLES case and volume averaged ? in a

  7. A Priori and a Posteriori Dietary Patterns during Pregnancy and Gestational Weight Gain: The Generation R Study

    PubMed Central

    Tielemans, Myrte J.; Erler, Nicole S.; Leermakers, Elisabeth T. M.; van den Broek, Marion; Jaddoe, Vincent W. V.; Steegers, Eric A. P.; Kiefte-de Jong, Jessica C.; Franco, Oscar H.

    2015-01-01

    Abnormal gestational weight gain (GWG) is associated with adverse pregnancy outcomes. We examined whether dietary patterns are associated with GWG. Participants included 3374 pregnant women from a population-based cohort in the Netherlands. Dietary intake during pregnancy was assessed with food-frequency questionnaires. Three a posteriori-derived dietary patterns were identified using principal component analysis: a “Vegetable, oil and fish”, a “Nuts, high-fiber cereals and soy”, and a “Margarine, sugar and snacks” pattern. The a priori-defined dietary pattern was based on national dietary recommendations. Weight was repeatedly measured around 13, 20 and 30 weeks of pregnancy; pre-pregnancy and maximum weight were self-reported. Normal weight women with high adherence to the “Vegetable, oil and fish” pattern had higher early-pregnancy GWG than those with low adherence (43 g/week (95% CI 16; 69) for highest vs. lowest quartile (Q)). Adherence to the “Margarine, sugar and snacks” pattern was associated with a higher prevalence of excessive GWG (OR 1.45 (95% CI 1.06; 1.99) Q4 vs. Q1). Normal weight women with higher scores on the “Nuts, high-fiber cereals and soy” pattern had more moderate GWG than women with lower scores (−0.01 (95% CI −0.02; −0.00) per SD). The a priori-defined pattern was not associated with GWG. To conclude, specific dietary patterns may play a role in early pregnancy but are not consistently associated with GWG. PMID:26569303

  8. The impact of the choice of radiative transfer model and inversion method on the OSIRIS ozone and nitrogen dioxide retrievals

    NASA Astrophysics Data System (ADS)

    Haley, Craig; McLinden, Chris; Sioris, Christopher; Brohede, Samuel

    Key to the retrieval of stratospheric minor species information from limb-scatter measurements are the selections of a radiative transfer model (RTM) and inversion method (solver). Here we assess the impact of choice of RTM and solver on the retrievals of stratospheric ozone and nitrogen dioxide from the OSIRIS instrument using the ‘Ozone Triplet' and Differential Optical Absorption Spectroscopy (DOAS) techniques that are used in the operational Level 2 processing algorithms. The RTMs assessed are LIMBTRAN, VECTOR, SCIARAYS, and SASKTRAN. The solvers studied include the Maximum A Posteriori (MAP), Maximum Likelihood (ML), Iterative Least Squares (ILS), and Chahine methods.

  9. Making School Choice Work

    ERIC Educational Resources Information Center

    DeArmond, Michael; Jochim, Ashley; Lake, Robin

    2014-01-01

    School choice is increasingly the new normal in urban education. But in cities with multiple public school options, how can civic leaders create a choice system that works for all families, whether they choose a charter or district public school? To answer this question, the Center on Reinventing Public Education (CRPE) researchers surveyed 4,000…

  10. Tense Choices in Citations.

    ERIC Educational Resources Information Center

    Hawes, Thomas; Thomas, Sarah

    1997-01-01

    Examines tense, aspect, and voice choices in the reporting verbs in a corpus of research articles from the "Journal of Psychosomatic Medicine." Investigates how such choices correlate with other syntactic elements in the citations, as well as with the discourse functions of the citations in their contexts. (TB)

  11. School Choice Marches forward

    ERIC Educational Resources Information Center

    Butcher, Jonathan

    2013-01-01

    One year ago, the "Wall Street Journal" dubbed 2011 "the year of school choice," opining that "this year is shaping up as the best for reformers in a very long time." School-choice laws took great strides in 2011, both in the number of programs that succeeded across states and also in the size and scope of the adopted…

  12. Retirement Choice 2014

    DTIC Science & Technology

    2014-09-01

    retirement plans at their 15th year of service.1 Once the final selection is made, the choice is irrevocable. The two options are: 1. High-3 retirement...and examples to help servicemembers.2 We have used a different approach that many have found useful in evalu- ating these retirement choices .3 Here, we

  13. The Illusion of Choice

    ERIC Educational Resources Information Center

    Chitty, Clyde

    2004-01-01

    Both New Labour and the Conservatives are keen to emphasise choice and diversity in crucial areas of public provision--and particularly with regard to education and health. In this article, "FORUM" co-Editor Clyde Chitty concentrates on recent proposals by the two main parties for promoting greater choice in secondary schooling in…

  14. Making Smart Food Choices

    MedlinePlus

    ... turn JavaScript on. Feature: Healthy Aging Making Smart Food Choices Past Issues / Winter 2015 Table of Contents Everyday ... NIH www.nia.nih.gov/Go4Life Making Smart Food Choices To maintain a healthy weight, balance the calories ...

  15. California's Districts of Choice

    ERIC Educational Resources Information Center

    Kronholz, June

    2014-01-01

    This article describes the results of a California state law established in 2010 that created "Districts of Choice." The District of Choice law was meant to encourage districts to compete for students by offering innovative programs and this-school-fits-my-child options that parents wanted. This designation meant that children from any…

  16. Children's Choices for 2008

    ERIC Educational Resources Information Center

    Reading Teacher, 2008

    2008-01-01

    Each year 12,500 school children from different regions of the United States read and vote on the newly published children's and young adults' trade books that they like best. The Children's Choices for 2008 list is the 34th in a series that first appeared as "Classroom Choices" in the November 1975 issue of "The Reading Teacher" (RT), a…

  17. More Choice, Less Crime

    ERIC Educational Resources Information Center

    Dills, Angela K.; Hernandez-Julian, Rey

    2011-01-01

    Previous research debates whether public school choice improves students' academic outcomes, but there is little examination of its effects on their nonacademic outcomes. We use data from a nationally representative sample of high school students, a previously developed Tiebout choice measure, and metropolitan-level data on teenage arrest rates to…

  18. Choice and reinforcement delay

    SciTech Connect

    Gentry, G.D.; Marr, M.J.

    1980-01-01

    Previous studies of choice between two delayed reinforcers have indicated that the relative immediacy of the reinforcer is a major determinant of the relative frequency of responding. Parallel studies of choice between two interresponse times have found exceptions to this generality. The present study looked at the choice by pigeons between two delays, one of which was always four times longer than the other, but whose absolute durations were varied across conditions. The results indicated that choice is not uniquely determined by the relative immediacy of reinforcement, but that absolute delays are also involved. Models for concurrent chained schedules appear to be more applicable to the present data than the matching relation; however, these too failed to predict choice for long delays.

  19. Measuring saliency in images: which experimental parameters for the assessment of image quality?

    NASA Astrophysics Data System (ADS)

    Fredembach, Clement; Woolfe, Geoff; Wang, Jue

    2012-01-01

    Predicting which areas of an image are perceptually salient or attended to has become an essential pre-requisite of many computer vision applications. Because observers are notoriously unreliable in remembering where they look a posteriori, and because asking where they look while observing the image necessarily in uences the results, ground truth about saliency and visual attention has to be obtained by gaze tracking methods. From the early work of Buswell and Yarbus to the most recent forays in computer vision there has been, perhaps unfortunately, little agreement on standardisation of eye tracking protocols for measuring visual attention. As the number of parameters involved in experimental methodology can be large, their individual in uence on the nal results is not well understood. Consequently, the performance of saliency algorithms, when assessed by correlation techniques, varies greatly across the literature. In this paper, we concern ourselves with the problem of image quality. Specically: where people look when judging images. We show that in this case, the performance gap between existing saliency prediction algorithms and experimental results is signicantly larger than otherwise reported. To understand this discrepancy, we rst devise an experimental protocol that is adapted to the task of measuring image quality. In a second step, we compare our experimental parameters with the ones of existing methods and show that a lot of the variability can directly be ascribed to these dierences in experimental methodology and choice of variables. In particular, the choice of a task, e.g., judging image quality vs. free viewing, has a great impact on measured saliency maps, suggesting that even for a mildly cognitive task, ground truth obtained by free viewing does not adapt well. Careful analysis of the prior art also reveals that systematic bias can occur depending on instrumental calibration and the choice of test images. We conclude this work by proposing a

  20. A comparative estimation of the errors in the sunspot coordinate catalog compiled at Cuba and the methods of their a posteriori decrease.

    NASA Astrophysics Data System (ADS)

    Nagovitsyn, Yu. A.; Nikonov, O. V.; Perez Doval, J.

    1992-06-01

    A comparison of the accuracy of the Cuba, Greenwich and Debrecen catalogs of sunspot coordinates has been made. A new method for a posteriori decrease of coordinate errors is given. The following conclusions have been made: 1. The accuracy of absolute heliographic coordinates for the Cuban catalog is 0.26 and for the Greenwich catalog is 0.32 of the heliographic degree. 2. Reduction to smoothed coordinate values improves the accuracy by a factor of 1.5. 3. Reduction values within the frame of the proposed technique REPORT to "pseudorelative" coordinates enables an improvement of the initial accuracy of sunspot coordinate measurement by 5 - 7 times.

  1. Resurgence as Choice.

    PubMed

    Shahan, Timothy A; Craig, Andrew R

    2016-10-26

    Resurgence is typically defined as an increase in a previously extinguished target behavior when a more recently reinforced alternative behavior is later extinguished. Some treatments of the phenomenon have suggested that it might also extend to circumstances where either the historic or more recently reinforced behavior is reduced by other non-extinction related means (e.g., punishment, decreases in reinforcement rate, satiation, etc.). Here we present a theory of resurgence suggesting that the phenomenon results from the same basic processes governing choice. In its most general form, the theory suggests that resurgence results from changes in the allocation of target behavior driven by changes in the values of the target and alternative options across time. Specifically, resurgence occurs when there is an increase in the relative value of an historically effective target option as a result of a subsequent devaluation of a more recently effective alternative option. We develop a more specific quantitative model of how extinction of the target and alternative responses in a typical resurgence paradigm might produce such changes in relative value across time using a temporal weighting rule. The example model does a good job in accounting for the effects of reinforcement rate and related manipulations on resurgence in simple schedules where Behavioral Momentum Theory has failed. We also discuss how the general theory might be extended to other parameters of reinforcement (e.g., magnitude, quality), other means to suppress target or alternative behavior (e.g., satiation, punishment, differential reinforcement of other behavior), and other factors (e.g., non- contingent versus contingent alternative reinforcement, serial alternative reinforcement, and multiple schedules).

  2. Make Better Food Choices

    MedlinePlus

    10 tips Nutrition Education Series make better food choices 10 tips for women’s health Fruits Grains Dairy Vegetables Protein Make yourself a priority and take time to care for yourself. ChooseMyPlate. gov ...

  3. Choice and conditioned reinforcement.

    PubMed Central

    Fantino, E; Freed, D; Preston, R A; Williams, W A

    1991-01-01

    A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only one of two concurrent-chains schedules and on only one of two corresponding concurrent-tandem schedules. This manipulation increased rate of conditioned reinforcement sharply in the chain but not in the tandem schedule. According to a formulation of delay-reduction theory, when the outcomes chosen (the terminal links) are equal, as in Experiment 1, choice should depend only on rate of primary reinforcement; thus, choice should be equivalent for the tandem and chain schedules despite a large difference in rate of conditioned reinforcement. When the outcomes chosen are unequal, however, as in Experiment 2, choice should depend upon both rate of primary reinforcement and relative signaled delay reduction; thus, larger preferences should occur in the chain than in the tandem schedules. These predictions were confirmed, suggesting that increasing the rate of conditioned reinforcement on concurrent-chains schedules may have no independent effect on choice. PMID:2037826

  4. Estimating random signal parameters from noisy images with nuisance parameters

    PubMed Central

    Whitaker, Meredith Kathryn; Clarkson, Eric; Barrett, Harrison H.

    2008-01-01

    In a pure estimation task, an object of interest is known to be present, and we wish to determine numerical values for parameters that describe the object. This paper compares the theoretical framework, implementation method, and performance of two estimation procedures. We examined the performance of these estimators for tasks such as estimating signal location, signal volume, signal amplitude, or any combination of these parameters. The signal is embedded in a random background to simulate the effect of nuisance parameters. First, we explore the classical Wiener estimator, which operates linearly on the data and minimizes the ensemble mean-squared error. The results of our performance tests indicate that the Wiener estimator can estimate amplitude and shape once a signal has been located, but is fundamentally unable to locate a signal regardless of the quality of the image. Given these new results on the fundamental limitations of Wiener estimation, we extend our methods to include more complex data processing. We introduce and evaluate a scanning-linear estimator that performs impressively for location estimation. The scanning action of the estimator refers to seeking a solution that maximizes a linear metric, thereby requiring a global-extremum search. The linear metric to be optimized can be derived as a special case of maximum a posteriori (MAP) estimation when the likelihood is Gaussian and a slowly varying covariance approximation is made. PMID:18545527

  5. Factors that influence beverage choices at meal times. An application of the food choice kaleidoscope framework.

    PubMed

    Mueller Loose, S; Jaeger, S R

    2012-12-01

    Beverages are consumed at almost every meal occasion, but knowledge about the factors that influence beverage choice is less than for food choice. The aim of this research was to characterize and quantify factors that influence beverage choices at meal times. Insights into what beverages are chosen by whom, when and where can be helpful for manufacturers, dieticians/health care providers, and health policy makers. A descriptive framework - the food choice kaleidoscope (Jaeger et al., 2011) - was applied to self-reported 24h food recall data from a sample of New Zealand consumers. Participants (n=164) described 8356 meal occasions in terms of foods and beverages consumed, and the contextual characteristics of the occasion. Beverage choice was explored with random-parameter logit regressions to reveal influences linked to food items eaten, context factors and person factors. Thereby this study contributed to the food choice kaleidoscope research approach by expressing the degree of context dependency in the form of odds ratios and according significance levels. The exploration of co-occurrence of beverages with food items suggests that beverage-meal item combinations can be meal specific. Furthermore, this study integrates psychographic variables into the 'person' mirror of the food choice kaleidoscope. A measure of habit in beverage choice was obtained from the inter-participant correlation.

  6. Choices, Frameworks and Refinement

    NASA Technical Reports Server (NTRS)

    Campbell, Roy H.; Islam, Nayeem; Johnson, Ralph; Kougiouris, Panos; Madany, Peter

    1991-01-01

    In this paper we present a method for designing operating systems using object-oriented frameworks. A framework can be refined into subframeworks. Constraints specify the interactions between the subframeworks. We describe how we used object-oriented frameworks to design Choices, an object-oriented operating system.

  7. A Matter of Choice

    ERIC Educational Resources Information Center

    Vriend, John

    1973-01-01

    Since the goal of helping the client make wise decisions is at the core of counseling, it is suggested that existentialism as a state of mind may give the contemporary counselor an outlook most conducive to achieving that goal. The entire role of choice must be dealt with by the counselor in light of the reality of current events. (Author)

  8. Deterministic Walks with Choice

    SciTech Connect

    Beeler, Katy E.; Berenhaut, Kenneth S.; Cooper, Joshua N.; Hunter, Meagan N.; Barr, Peter S.

    2014-01-10

    This paper studies deterministic movement over toroidal grids, integrating local information, bounded memory and choice at individual nodes. The research is motivated by recent work on deterministic random walks, and applications in multi-agent systems. Several results regarding passing tokens through toroidal grids are discussed, as well as some open questions.

  9. Project Choice: Lessons Learned.

    ERIC Educational Resources Information Center

    Ewing Marion Kauffman Foundation, Kansas City, MO.

    Project Choice began with a simple goal: to increase the number of inner-city students who graduate from high school on time and become productive members of society. To that end, Ewing M. Kauffman, his Foundation, and associates designed and implemented a program that promised postsecondary education or training to some students in the Kansas…

  10. Choices, Not Circumstances.

    ERIC Educational Resources Information Center

    National Education Association, Washington, DC. Div. of Instruction and Professional Development.

    Following a brief account of the circumstances of migrant workers and the status of migrant education in the United States, this pamphlet describes how the National Education Association (NEA) has impacted and will continue to impact the process of providing educational choices for migrant students. The NEA has consistently testified before…

  11. Too Few Choices

    ERIC Educational Resources Information Center

    Murray, Meg

    2007-01-01

    In this article, the author, who is a scientist, a wife and a mother of two preschool children talks about how these two roles exerted a disproportionate impact on her career choices. She is also an X-Gal, one of a group of nine female biologists who have banded together to offer one another advice and support as they seek careers in academic…

  12. The Choice for Learning

    ERIC Educational Resources Information Center

    Bennett, Scott

    2006-01-01

    We are building conventional library space without making the paradigm shift our digital environment requires. The chief obstacles to change lie in our conception of readers as information consumers, in our allegiance to library operations as the drivers of library design, and in the choice made between foundational and non-foundational views of…

  13. Children's Choices for 2003.

    ERIC Educational Resources Information Center

    Reading Teacher, 2003

    2003-01-01

    Presents 103 titles for the 2003 Children's Choice grouped by reading levels: beginning, young, intermediate, and advanced readers. Provides the title, author, illustrator, publisher, ISBN, and price for each title as well as a brief annotation prepared by a review team. (SG)

  14. Quantifying the impact of material-model error on macroscale quantities-of-interest using multiscale a posteriori error-estimation techniques

    SciTech Connect

    Brown, Judith A.; Bishop, Joseph E.

    2016-07-20

    An a posteriori error-estimation framework is introduced to quantify and reduce modeling errors resulting from approximating complex mesoscale material behavior with a simpler macroscale model. Such errors may be prevalent when modeling welds and additively manufactured structures, where spatial variations and material textures may be present in the microstructure. We consider a case where a <100> fiber texture develops in the longitudinal scanning direction of a weld. Transversely isotropic elastic properties are obtained through homogenization of a microstructural model with this texture and are considered the reference weld properties within the error-estimation framework. Conversely, isotropic elastic properties are considered approximate weld properties since they contain no representation of texture. Errors introduced by using isotropic material properties to represent a weld are assessed through a quantified error bound in the elastic regime. Lastly, an adaptive error reduction scheme is used to determine the optimal spatial variation of the isotropic weld properties to reduce the error bound.

  15. Fixing the c Parameter in the Three-Parameter Logistic Model

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2012-01-01

    For several decades, the "three-parameter logistic model" (3PLM) has been the dominant choice for practitioners in the field of educational measurement for modeling examinees' response data from multiple-choice (MC) items. Past studies, however, have pointed out that the c-parameter of 3PLM should not be interpreted as a guessing parameter. This…

  16. Estimating nuisance parameters in inverse problems

    NASA Astrophysics Data System (ADS)

    Aravkin, Aleksandr Y.; van Leeuwen, Tristan

    2012-11-01

    Many inverse problems include nuisance parameters which, while not of direct interest, are required to recover primary parameters. The structure of these problems allows efficient optimization strategies—a well-known example is variable projection, where nonlinear least-squares problems which are linear in some parameters can be very efficiently optimized. In this paper, we extend the idea of projecting out a subset over the variables to a broad class of maximum likelihood and maximum a posteriori likelihood problems with nuisance parameters, such as variance or degrees of freedom (d.o.f.). As a result, we are able to incorporate nuisance parameter estimation into large-scale constrained and unconstrained inverse problem formulations. We apply the approach to a variety of problems, including estimation of unknown variance parameters in the Gaussian model, d.o.f. parameter estimation in the context of robust inverse problems, and automatic calibration. Using numerical examples, we demonstrate improvement in recovery of primary parameters for several large-scale inverse problems. The proposed approach is compatible with a wide variety of algorithms and formulations, and its implementation requires only minor modifications to existing algorithms.

  17. A Scalar Product Model for the Multidimensional Scaling of Choice

    ERIC Educational Resources Information Center

    Bechtel, Gordon G.; And Others

    1971-01-01

    Contains a solution for the multidimensional scaling of pairwise choice when individuals are represented as dimensional weights. The analysis supplies an exact least squares solution and estimates of group unscalability parameters. (DG)

  18. Retirement Choice: 2010

    DTIC Science & Technology

    2010-03-01

    Retirement Choice: 2010 Aline Quester • Lewis G. Lee • Anita Hattiangadi • Robert Shuford CRM D0022180.A1/Final March 2010 Report Documentation Page...824-2123. Copyright  2010 CNA Approved for distribution: March 2010 Anita Hattiangadi Marine Corps Manpower Team Resource Analysis Division Contents...several CNA col- leagues: Gerald Cox, Donald Cymrot, Michael Hansen, and Ann Par- cell. Kathleen Utgoff (former Director of the Pension Benefit

  19. 2014 Retirement Choices

    DTIC Science & Technology

    2014-09-01

    transferred from another branch of the military. It is called Date of Entry into Armed Forces ( DEAF ), Date of Initial Entry to Military Service...to compensate for inflation (cost-of-living adjustment, or COLA) at the Consumer Price Index (CPI) rate minus 1 percent. Under the High-3 option, a...compensate for the full value of inflation (cost-of-living adjustment) at the CPI rate . 5 Both retirement choices have the following features

  20. Optimal filtration of the atmospheric parameters profiles

    NASA Technical Reports Server (NTRS)

    Zuev, V. E.; Glazov, G. N.; Igonin, G. M.

    1986-01-01

    The idea of optimal Marcovian filtration of fluctuating profiles from lidar signals is developed but as applied to a double-frequency sounding which allows the use of large cross sections of elastic scattering and correct separation of the contributions due to aerosol and Rayleigh scatterings from the total lidar return. The filtration efficiency is shown under different conditions of sounding using a computer model. The accuracy of restituted profiles (temperature, pressure, density) is determined by the elements of a posteriori matrix K. The results obtained allow the determination of the lidar power required for providing the necessary accuracy of restitution of the atmospheric parameter profiles at chosen wavelengths of sounding in the ultraviolet and visible range.

  1. Alternative fuels and vehicles choice model

    SciTech Connect

    Greene, D.L.

    1994-10-01

    This report describes the theory and implementation of a model of alternative fuel and vehicle choice (AFVC), designed for use with the US Department of Energy`s Alternative Fuels Trade Model (AFTM). The AFTM is a static equilibrium model of the world supply and demand for liquid fuels, encompassing resource production, conversion processes, transportation, and consumption. The AFTM also includes fuel-switching behavior by incorporating multinomial logit-type equations for choice of alternative fuel vehicles and alternative fuels. This allows the model to solve for market shares of vehicles and fuels, as well as for fuel prices and quantities. The AFVC model includes fuel-flexible, bi-fuel, and dedicated fuel vehicles. For multi-fuel vehicles, the choice of fuel is subsumed within the vehicle choice framework, resulting in a nested multinomial logit design. The nesting is shown to be required by the different price elasticities of fuel and vehicle choice. A unique feature of the AFVC is that its parameters are derived directly from the characteristics of alternative fuels and vehicle technologies, together with a few key assumptions about consumer behavior. This not only establishes a direct link between assumptions and model predictions, but facilitates sensitivity testing, as well. The implementation of the AFVC model as a spreadsheet is also described.

  2. Diet Choices to Prevent Cancer

    MedlinePlus

    ... Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight Loss and Diet Plans Nutrients and Nutritional ... Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight Loss and Diet Plans Nutrients and Nutritional ...

  3. The malleability of intertemporal choice

    PubMed Central

    Lempert, Karolina M.; Phelps, Elizabeth A.

    2015-01-01

    Intertemporal choices are ubiquitous: people often have to choose between outcomes realized at different times. Although it is generally believed that people have stable tendencies toward being impulsive or patient, an emerging body of evidence indicates that intertemporal choice is malleable and can be profoundly influenced by context. How the choice is framed, or the state of the decision-maker at the time of choice, can induce a shift in preference. Framing effects are underpinned by: allocation of attention to choice attributes, reference-dependence and time construal. Incidental affective states and prospection also influence intertemporal choice. We advocate that intertemporal choice models account for these context effects, and encourage the use of this knowledge to nudge people toward making more advantageous choices. PMID:26483153

  4. A Bayesian approach to tracking patients having changing pharmacokinetic parameters

    NASA Technical Reports Server (NTRS)

    Bayard, David S.; Jelliffe, Roger W.

    2004-01-01

    This paper considers the updating of Bayesian posterior densities for pharmacokinetic models associated with patients having changing parameter values. For estimation purposes it is proposed to use the Interacting Multiple Model (IMM) estimation algorithm, which is currently a popular algorithm in the aerospace community for tracking maneuvering targets. The IMM algorithm is described, and compared to the multiple model (MM) and Maximum A-Posteriori (MAP) Bayesian estimation methods, which are presently used for posterior updating when pharmacokinetic parameters do not change. Both the MM and MAP Bayesian estimation methods are used in their sequential forms, to facilitate tracking of changing parameters. Results indicate that the IMM algorithm is well suited for tracking time-varying pharmacokinetic parameters in acutely ill and unstable patients, incurring only about half of the integrated error compared to the sequential MM and MAP methods on the same example.

  5. School Choice. Trends and Issues.

    ERIC Educational Resources Information Center

    Hadderman, Margaret, Comp.

    This document examines many of the issues surrounding school choice. It summarizes the prevalence of school choice and touches on elements of the debate, such as the dilemma in finding the right balance between individual/family freedom and the interests of the community. In looking at school-choice options, the paper divides them into…

  6. Dynamics of Choice: A Tutorial

    ERIC Educational Resources Information Center

    Baum, William M.

    2010-01-01

    Choice may be defined as the allocation of behavior among activities. Since all activities take up time, choice is conveniently thought of as the allocation of time among activities, even if activities like pecking are most easily measured by counting. Since dynamics refers to change through time, the dynamics of choice refers to change of…

  7. Student Curriculum Choice and Change.

    ERIC Educational Resources Information Center

    Miner, Norris

    This study investigated changes in student curriculum choice at Seminole Junior College (Florida) A code system was developed for 72 curriculum choices (23 in terminal degree areas), grouped into 19 broad clusters. A computerized Student Flow Matrix was then constructed to display the first and second term curriculum choices of 1,391 students who…

  8. Overconfidence and Career Choice

    PubMed Central

    Schulz, Jonathan F.; Thöni, Christian

    2016-01-01

    People self-assess their relative ability when making career choices. Thus, confidence in their own abilities is likely an important factor for selection into various career paths. In a sample of 711 first-year students we examine whether there are systematic differences in confidence levels across fields of study. We find that our experimental confidence measures significantly vary between fields of study: While students in business related academic disciplines (Political Science, Law, Economics, and Business Administration) exhibit the highest confidence levels, students of Humanities range at the other end of the scale. This may have important implications for subsequent earnings and professions students select themselves in. PMID:26808273

  9. Overconfidence and Career Choice.

    PubMed

    Schulz, Jonathan F; Thöni, Christian

    2016-01-01

    People self-assess their relative ability when making career choices. Thus, confidence in their own abilities is likely an important factor for selection into various career paths. In a sample of 711 first-year students we examine whether there are systematic differences in confidence levels across fields of study. We find that our experimental confidence measures significantly vary between fields of study: While students in business related academic disciplines (Political Science, Law, Economics, and Business Administration) exhibit the highest confidence levels, students of Humanities range at the other end of the scale. This may have important implications for subsequent earnings and professions students select themselves in.

  10. Variation, Repetition, And Choice

    PubMed Central

    Abreu-Rodrigues, Josele; Lattal, Kennon A; dos Santos, Cristiano V; Matos, Ricardo A

    2005-01-01

    Experiment 1 investigated the controlling properties of variability contingencies on choice between repeated and variable responding. Pigeons were exposed to concurrent-chains schedules with two alternatives. In the REPEAT alternative, reinforcers in the terminal link depended on a single sequence of four responses. In the VARY alternative, a response sequence in the terminal link was reinforced only if it differed from the n previous sequences (lag criterion). The REPEAT contingency generated low, constant levels of sequence variation whereas the VARY contingency produced levels of sequence variation that increased with the lag criterion. Preference for the REPEAT alternative tended to increase directly with the degree of variation required for reinforcement. Experiment 2 examined the potential confounding effects in Experiment 1 of immediacy of reinforcement by yoking the interreinforcer intervals in the REPEAT alternative to those in the VARY alternative. Again, preference for REPEAT was a function of the lag criterion. Choice between varying and repeating behavior is discussed with respect to obtained behavioral variability, probability of reinforcement, delay of reinforcement, and switching within a sequence. PMID:15828592

  11. Quantifying the impact of material-model error on macroscale quantities-of-interest using multiscale a posteriori error-estimation techniques

    DOE PAGES

    Brown, Judith A.; Bishop, Joseph E.

    2016-07-20

    An a posteriori error-estimation framework is introduced to quantify and reduce modeling errors resulting from approximating complex mesoscale material behavior with a simpler macroscale model. Such errors may be prevalent when modeling welds and additively manufactured structures, where spatial variations and material textures may be present in the microstructure. We consider a case where a <100> fiber texture develops in the longitudinal scanning direction of a weld. Transversely isotropic elastic properties are obtained through homogenization of a microstructural model with this texture and are considered the reference weld properties within the error-estimation framework. Conversely, isotropic elastic properties are considered approximatemore » weld properties since they contain no representation of texture. Errors introduced by using isotropic material properties to represent a weld are assessed through a quantified error bound in the elastic regime. Lastly, an adaptive error reduction scheme is used to determine the optimal spatial variation of the isotropic weld properties to reduce the error bound.« less

  12. A simple robust and accurate a posteriori sub-cell finite volume limiter for the discontinuous Galerkin method on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Dumbser, Michael; Loubère, Raphaël

    2016-08-01

    In this paper we propose a simple, robust and accurate nonlinear a posteriori stabilization of the Discontinuous Galerkin (DG) finite element method for the solution of nonlinear hyperbolic PDE systems on unstructured triangular and tetrahedral meshes in two and three space dimensions. This novel a posteriori limiter, which has been recently proposed for the simple Cartesian grid case in [62], is able to resolve discontinuities at a sub-grid scale and is substantially extended here to general unstructured simplex meshes in 2D and 3D. It can be summarized as follows: At the beginning of each time step, an approximation of the local minimum and maximum of the discrete solution is computed for each cell, taking into account also the vertex neighbors of an element. Then, an unlimited discontinuous Galerkin scheme of approximation degree N is run for one time step to produce a so-called candidate solution. Subsequently, an a posteriori detection step checks the unlimited candidate solution at time t n + 1 for positivity, absence of floating point errors and whether the discrete solution has remained within or at least very close to the bounds given by the local minimum and maximum computed in the first step. Elements that do not satisfy all the previously mentioned detection criteria are flagged as troubled cells. For these troubled cells, the candidate solution is discarded as inappropriate and consequently needs to be recomputed. Within these troubled cells the old discrete solution at the previous time tn is scattered onto small sub-cells (Ns = 2 N + 1 sub-cells per element edge), in order to obtain a set of sub-cell averages at time tn. Then, a more robust second order TVD finite volume scheme is applied to update the sub-cell averages within the troubled DG cells from time tn to time t n + 1. The new sub-grid data at time t n + 1 are finally gathered back into a valid cell-centered DG polynomial of degree N by using a classical conservative and higher order

  13. Connecting cognition and consumer choice.

    PubMed

    Bartels, Daniel M; Johnson, Eric J

    2015-02-01

    We describe what can be gained from connecting cognition and consumer choice by discussing two contexts ripe for interaction between the two fields. The first-context effects on choice-has already been addressed by cognitive science yielding insights about cognitive process but there is promise for more interaction. The second is learning and representation in choice where relevant theories in cognitive science could be informed by consumer choice, and in return, could pose and answer new questions. We conclude by discussing how these two fields of research stand to benefit from more interaction, citing examples of how interfaces of cognitive science with other fields have been illuminating for theories of cognition.

  14. Parental Voucher Enrollment Decisions: Choice within Choice in New Orleans

    ERIC Educational Resources Information Center

    Beabout, Brian R.; Cambre, Belinda M.

    2013-01-01

    Set in the context of a choice-saturated public school system, this study examines the school choice process of low-income parents who participated in Louisiana's 2008 voucher program. Based on semistructured interviews with 16 parents at 1 Catholic school, we report that spirituality, small class and school size, character/values, familiarity,…

  15. Introduction: What Will Be the Supreme Court's Choice on Choice?

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2001-01-01

    Introduces article by Kemerer that takes issue with the conclusions reached by Elizabeth and Andrew Lugg in their article entitled "Vouchers as School Choice: An Analysis of 'Jackson v. Benson': The Milwaukee Parental Choice Program" in the April 2000 issue of "The Journal of Law and Education." (PKP)

  16. Deafness, culture, and choice.

    PubMed

    Levy, N

    2002-10-01

    The recent controversy surrounding the choice, by a deaf lesbian couple, to have children who were themselves deaf, has focused attention on the ethics of choosing (apparent) disabilities for children. Deaf activists argue that deafness is not a disability, but instead the constitutive condition of access to a rich culture. Being deaf carries disadvantages with it, but these are a product of discrimination, not of the condition itself. It is, however, implausible to think that all the disadvantages which stem from deafness are social in origin. Moreover, though it may be true that being deaf carries with it the important compensation of access to a rich culture, no physical condition is required for such access. Cultures are simply the kind of things to which we are born, and therefore to which the children of deaf parents, hearing or deaf, normally belong. Thus these parents are making a mistake in choosing deafness for their children. Given their own experience of isolation as children, however, it is a mistake which is understandable, and our reaction to them ought to be compassion, not condemnation.

  17. Addiction: Choice or Compulsion?

    PubMed Central

    Henden, Edmund; Melberg, Hans Olav; Røgeberg, Ole Jørgen

    2013-01-01

    Normative thinking about addiction has traditionally been divided between, on the one hand, a medical model which sees addiction as a disease characterized by compulsive and relapsing drug use over which the addict has little or no control and, on the other, a moral model which sees addiction as a choice characterized by voluntary behavior under the control of the addict. Proponents of the former appeal to evidence showing that regular consumption of drugs causes persistent changes in the brain structures and functions known to be involved in the motivation of behavior. On this evidence, it is often concluded that becoming addicted involves a transition from voluntary, chosen drug use to non-voluntary compulsive drug use. Against this view, proponents of the moral model provide ample evidence that addictive drug use involves voluntary chosen behavior. In this article we argue that although they are right about something, both views are mistaken. We present a third model that neither rules out the view of addictive drug use as compulsive, nor that it involves voluntary chosen behavior. PMID:23966955

  18. Evidence based contraceptive choices.

    PubMed

    Scott, Alison; Glasier, Anna

    2006-10-01

    People who attend for contraceptive advice have usually formulated an idea of the type of contraceptive that will suit them best. They may wish to use a method that is long, short or medium acting. These are defined as follows: Long-acting method requires renewal no more frequently than every 3 months (e.g. injectable or intrauterine). Short-acting method used daily or with every act of intercourse (e.g. pills, condoms) Medium-acting method requires renewal weekly or monthly (e.g. ring, patch). For men the choice is limited to condoms or vasectomy. Some women do not wish to use hormonal preparations or have an intrauterine device (IUD) or implant inserted. There may also be cultural influences making certain methods of contraception unacceptable. Each of these factors influences the final decision of which method of contraception is decided upon. In addition to taking a full medical and sexual history to identify any risks to the individual's health, which might be increased by a particular contraceptive, time must be spent discussing the options available. It is important to ensure that there is a full understanding of the advantages and disadvantages of each method. The most successful contraceptive method is likely to be the one that the woman (or man) chooses, rather than the one the clinician chooses for them. Access for women to contraception can be improved by having convenient clinic times and service developments such as nurse prescribing and Patient Group Directions.

  19. Eye Movements in Risky Choice

    PubMed Central

    Hermens, Frouke; Matthews, William J.

    2015-01-01

    Abstract We asked participants to make simple risky choices while we recorded their eye movements. We built a complete statistical model of the eye movements and found very little systematic variation in eye movements over the time course of a choice or across the different choices. The only exceptions were finding more (of the same) eye movements when choice options were similar, and an emerging gaze bias in which people looked more at the gamble they ultimately chose. These findings are inconsistent with prospect theory, the priority heuristic, or decision field theory. However, the eye movements made during a choice have a large relationship with the final choice, and this is mostly independent from the contribution of the actual attribute values in the choice options. That is, eye movements tell us not just about the processing of attribute values but also are independently associated with choice. The pattern is simple—people choose the gamble they look at more often, independently of the actual numbers they see—and this pattern is simpler than predicted by decision field theory, decision by sampling, and the parallel constraint satisfaction model. © 2015 The Authors. Journal of Behavioral Decision Making published by John Wiley & Sons Ltd. PMID:27522985

  20. Inside a School of Choice.

    ERIC Educational Resources Information Center

    Fizzell, Robert L.

    1987-01-01

    Outlines the benefits individual students experience at the Alternative Learning Center in Evergreen, Washington. An important element in the successful operation of a school of choice is the admissions procedure. To provide a clear and informed decision in school choice this school's admission procedure includes information, screening, and…

  1. The Globalisation of School Choice?

    ERIC Educational Resources Information Center

    Forsey, Martin, Ed.; Davies, Scott, Ed.; Walford, Geoffrey, Ed.

    2008-01-01

    "Which school should I choose for my child?" For many parents, this question is one of the most important of their lives. "School choice" is a slogan being voiced around the globe, conjuring images of a marketplace with an abundance of educational options. Those promoting educational choice also promise equality, social…

  2. PATERNAL INFLUENCE ON CAREER CHOICE.

    ERIC Educational Resources Information Center

    WERTS, CHARLES E.

    FATHER'S OCCUPATION WAS COMPARED WITH SON'S CAREER CHOICE FOR A SAMPLE OF 76,015 MALE, COLLEGE FRESHMEN. RESULTS INDICATED THAT CERTAIN TYPES OF FATHERS' OCCUPATIONS WERE ASSOCIATED WITH SIMILAR TYPES OF CAREER CHOICES BY SONS. BOYS WHOSE FATHERS WERE IN SCIENTIFIC OCCUPATIONS (ENGINEERS, MILITARY OFFICERS, ARCHITECTS, BIOLOGISTS, CHEMISTS, AND…

  3. College Choice in the Philippines

    ERIC Educational Resources Information Center

    Tan, Christine Joy

    2009-01-01

    This descriptive and correlational study examined the applicability of major U.S. college choice factors to Philippine high school seniors. A sample of 226 students from a private school in Manila completed the College Choice Survey for High School Seniors. Cronbach's alpha for the survey composite index was 0.933. The purposes of this…

  4. School Choice with Chinese Characteristics

    ERIC Educational Resources Information Center

    Wu, Xiaoxin

    2012-01-01

    This paper explores the major characteristics of school choice in the Chinese context. It highlights the involvement of cultural and economic capital, such as choice fees, donations, prize-winning certificates and awards in gaining school admission, as well as the use of social capital in the form of "guanxi". The requirement for these…

  5. Preference Reversal in Multiattribute Choice

    ERIC Educational Resources Information Center

    Tsetsos, Konstantinos; Usher, Marius; Chater, Nick

    2010-01-01

    A central puzzle for theories of choice is that people's preferences between options can be reversed by the presence of decoy options (that are not chosen) or by the presence of other irrelevant options added to the choice set. Three types of reversal effect reported in the decision-making literature, the attraction, compromise, and similarity…

  6. School Choice: To What End?

    ERIC Educational Resources Information Center

    Wagner, Tony

    1996-01-01

    Debunks two fantasies: the feasibility of a free-market educational system and the idea that greater choice automatically means better schools. Public education is too labor-intensive and undercapitalized to be profitable. Communities need "skunk works" schools of choice to do research and development and smaller, collaboratively managed…

  7. Religious Education and Religious Choice

    ERIC Educational Resources Information Center

    Hand, Michael

    2015-01-01

    According to the "religious choice case" for compulsory religious education, pupils have a right to be made aware of the religious and irreligious paths open to them and equipped with the wherewithal to choose between them. A familiar objection to this argument is that the idea of religious choice reduces religion to a matter of taste. I…

  8. School: A Matter of Choice.

    ERIC Educational Resources Information Center

    Organisation for Economic Cooperation and Development, Paris (France). Centre for Educational Research and Innovation.

    Measures to improve parent and student choice of school have recently become an important issue for educational reform in a number of Organisation for Economic Co-operation and Development (OECD) countries. This book summarizes the school-choice experiences of selected OECD countries. The data, collected by the OECD/Centre for Educational Research…

  9. The Supply Side of Choice

    ERIC Educational Resources Information Center

    Hill, Paul T.

    2005-01-01

    New school creation is key to success of choice. For the last two decades, the struggle over school choice has focused on freeing up parents to choose. It continues to this day, with growing success in the forms of public and private voucher programs, charter school laws in 40 states and the District of Columbia, and state and federal laws that…

  10. School Choice: Examining the Evidence.

    ERIC Educational Resources Information Center

    Rasell, Edith, Ed.; Rothstein, Richard, Ed.

    This book presents a summary of school-choice issues, and is organized around a 1992 seminar entitled "Choice: What Role in American Education?" Each part presents a set of conference papers, followed by discussants' remarks and excerpts from audience discussion. The introduction summarizes the papers' positions and conclusions. Participants…

  11. Economic analysis of the first 20 years of universal hepatitis B vaccination program in Italy: an a posteriori evaluation and forecast of future benefits.

    PubMed

    Boccalini, Sara; Taddei, Cristina; Ceccherini, Vega; Bechini, Angela; Levi, Miriam; Bartolozzi, Dario; Bonanni, Paolo

    2013-05-01

    Italy was one of the first countries in the world to introduce a routine vaccination program against HBV for newborns and 12-y-old children. From a clinical point of view, such strategy was clearly successful. The objective of our study was to verify whether, at 20 y from its implementation, hepatitis B universal vaccination had positive effects also from an economic point of view. An a posteriori analysis evaluated the impact that the hepatitis B immunization program had up to the present day. The implementation of vaccination brought an extensive reduction of the burden of hepatitis B-related diseases in the Italian population. As a consequence, the past and future savings due to clinical costs avoided are particularly high. We obtained a return on investment nearly equal to 1 from the National Health Service perspective, and a benefit-to-cost ratio slightly less than 1 for the Societal perspective, considering only the first 20 y from the start of the program. In the longer-time horizon, ROI and BCR values were positive (2.78 and 2.46, respectively). The break-even point was already achieved few years ago for the NHS and for the Society, and since then more and more money is progressively saved. The implementation of universal hepatitis B vaccination was very favorable during the first 20 y of adoption, and further benefits will be increasingly evident in the future. The hepatitis B vaccination program in Italy is a clear example of the great impact that universal immunization is able to provide in the medium-long-term when health care authorities are so wise as to invest in prevention.

  12. SU-E-J-170: Beyond Single-Cycle 4DCT: Maximum a Posteriori (MAP) Reconstruction-Based Binning-Free Multicycle 4DCT for Lung Radiotherapy

    SciTech Connect

    Cheung, Y; Sawant, A; Hinkle, J; Joshi, S

    2014-06-01

    Purpose: Thoracic motion changes from cycle-to-cycle and day-to-day. Conventional 4DCT does not capture these cycle to cycle variations. We present initial results of a novel 4DCT reconstruction technique based on maximum a posteriori (MAP) reconstruction. The technique uses the same acquisition process (and therefore dose) as a conventional 4DCT in order to create a high spatiotemporal resolution cine CT that captures several breathing cycles. Methods: Raw 4DCT data were acquired from a lung cancer patient. The continuous 4DCT was reconstructed using MAP algorithm which uses the raw, time-stamped CT data to reconstruct images while simultaneously estimating deformation in the subject's anatomy. This framework incorporates physical effects such as hysteresis and is robust to detector noise and irregular breathing patterns. The 4D image is described in terms of a 3D reference image defined at one end of the hysteresis loop, and two deformation vector fields (DVFs) corresponding to inhale motion and exhale motion respectively. The MAP method uses all of the CT projection data and maximizes the log posterior in order to iteratively estimate a timevariant deformation vector field that describes the entire moving and deforming volume. Results: The MAP 4DCT yielded CT-quality images for multiple cycles corresponding to the entire duration of CT acquisition, unlike the conventional 4DCT, which only yielded a single cycle. Variations such as amplitude and frequency changes and baseline shifts were clearly captured by the MAP 4DC Conclusion: We have developed a novel, binning-free, parameterized 4DCT reconstruction technique that can capture cycle-to-cycle variations of respiratory motion. This technique provides an invaluable tool for respiratory motion management research. This work was supported by funding from the National Institutes of Health and VisionRT Ltd. Amit Sawant receives research funding from Varian Medical Systems, Vision RT and Elekta.

  13. Preference for free choice over forced choice in pigeons

    PubMed Central

    Catania, A. Charles; Sagvolden, Terje

    1980-01-01

    In a six-key chamber variable-interval initial links of concurrent-chain schedules operated on two lower white keys. Terminal links operated on four upper keys; green keys were correlated with fixed-interval reinforcement and red keys with extinction. Free-choice terminal links arranged three green keys and one red key; forced-choice terminal links arranged one green key and three red keys. Thus, terminal links were equivalent in number, variety, and information value (in bits) of the keylights. Preferences (relative initial-link rates) were studied both with location of the odd key color varying over successive terminal links and with the odd color fixed at key locations that had controlled either relatively high or relatively low terminal-link response rates. Free choice was consistently preferred to forced choice. Magnitude of preference did not vary systematically with terminal-link response rate or stimulus control by green and red keys. The origins of free-choice preference could be ontogenic or phylogenic: organisms may learn that momentarily preferred alternatives are more often available in free than in forced choice, and evolutionary contingencies may favor the survival of organisms that prefer free to forced choice. PMID:16812181

  14. The logistics of choice.

    PubMed

    Killeen, Peter R

    2015-07-01

    The generalized matching law (GML) is reconstructed as a logistic regression equation that privileges no particular value of the sensitivity parameter, a. That value will often approach 1 due to the feedback that drives switching that is intrinsic to most concurrent schedules. A model of that feedback reproduced some features of concurrent data. The GML is a law only in the strained sense that any equation that maps data is a law. The machine under the hood of matching is in all likelihood the very law that was displaced by the Matching Law. It is now time to return the Law of Effect to centrality in our science.

  15. Eye Movements in Strategic Choice

    PubMed Central

    Gächter, Simon; Noguchi, Takao; Mullett, Timothy L.

    2015-01-01

    Abstract In risky and other multiattribute choices, the process of choosing is well described by random walk or drift diffusion models in which evidence is accumulated over time to threshold. In strategic choices, level‐k and cognitive hierarchy models have been offered as accounts of the choice process, in which people simulate the choice processes of their opponents or partners. We recorded the eye movements in 2 × 2 symmetric games including dominance‐solvable games like prisoner's dilemma and asymmetric coordination games like stag hunt and hawk–dove. The evidence was most consistent with the accumulation of payoff differences over time: we found longer duration choices with more fixations when payoffs differences were more finely balanced, an emerging bias to gaze more at the payoffs for the action ultimately chosen, and that a simple count of transitions between payoffs—whether or not the comparison is strategically informative—was strongly associated with the final choice. The accumulator models do account for these strategic choice process measures, but the level‐k and cognitive hierarchy models do not. © 2015 The Authors. Journal of Behavioral Decision Making published by John Wiley & Sons Ltd. PMID:27513881

  16. Understanding Parameter Invariance in Unidimensional IRT Models

    ERIC Educational Resources Information Center

    Rupp, Andre A.; Zumbo, Bruno D.

    2006-01-01

    One theoretical feature that makes item response theory (IRT) models those of choice for many psychometric data analysts is parameter invariance, the equality of item and examinee parameters from different examinee populations or measurement conditions. In this article, using the well-known fact that item and examinee parameters are identical only…

  17. Effort, success, and nonuse determine arm choice.

    PubMed

    Schweighofer, Nicolas; Xiao, Yupeng; Kim, Sujin; Yoshioka, Toshinori; Gordon, James; Osu, Rieko

    2015-07-01

    How do humans choose one arm or the other to reach single targets in front of the body? Current theories of reward-driven decisionmaking predict that choice results from a comparison of "action values," which are the expected rewards for possible actions in a given state. In addition, current theories of motor control predict that in planning arm movements, humans minimize an expected motor cost that balances motor effort and endpoint accuracy. Here, we test the hypotheses that arm choice is determined by comparison of action values comprising expected effort and expected task success for each arm, as well as a handedness bias. Right-handed subjects, in either a large or small target condition, were first instructed to use each hand in turn to shoot through an array of targets and then to choose either hand to shoot through the same targets. Effort was estimated via inverse kinematics and dynamics. A mixed-effects logistic-regression analysis showed that, as predicted, both expected effort and expected success predicted choice, as did arm use in the preceding trial. Finally, individual parameter estimation showed that the handedness bias correlated with mean difference between right- and left-arm success, leading to overall lower use of the left arm. We discuss our results in light of arm nonuse in individuals' poststroke.

  18. The Neuroscience of Consumer Choice

    PubMed Central

    Hsu, Ming; Yoon, Carolyn

    2015-01-01

    We review progress and challenges relating to scientific and applied goals of the nascent field of consumer neuroscience. Scientifically, substantial progress has been made in understanding the neurobiology of choice processes. Further advances, however, require researchers to begin clarifying the set of developmental and cognitive processes that shape and constrain choices. First, despite the centrality of preferences in theories of consumer choice, we still know little about where preferences come from and the underlying developmental processes. Second, the role of attention and memory processes in consumer choice remains poorly understood, despite importance ascribed to them in interpreting data from the field. The applied goal of consumer neuroscience concerns our ability to translate this understanding to augment prediction at the population level. Although the use of neuroscientific data for market-level predictions remains speculative, there is growing evidence of superiority in specific cases over existing market research techniques. PMID:26665152

  19. How do stereotypes influence choice?

    PubMed

    Chaxel, Anne-Sophie

    2015-05-01

    In the study reported here, I tracked one process through which stereotypes affect choice. The Implicit Association Test (IAT) and a measurement of predecisional information distortion were used to assess the influence of the association between male gender and career on the evaluation of information related to the job performance of stereotypical targets (male) and nonstereotypical targets (female). When the IAT revealed a strong association between male gender and career and the installed leader in the choice process was a stereotypical target, decision makers supported the leader with more proleader distortion; when the IAT revealed a strong association between male gender and career and the installed leader in the choice process was a nonstereotypical target, decision makers supported the trailer with less antitrailer distortion. A stronger association between male gender and career therefore resulted in an upward shift of the evaluation related to the stereotypical target (both as a trailer and a leader), which subsequently biased choice.

  20. Hyperbolic value addition and general models of animal choice.

    PubMed

    Mazur, J E

    2001-01-01

    Three mathematical models of choice--the contextual-choice model (R. Grace, 1994), delay-reduction theory (N. Squires & E. Fantino, 1971), and a new model called the hyperbolic value-added model--were compared in their ability to predict the results from a wide variety of experiments with animal subjects. When supplied with 2 or 3 free parameters, all 3 models made fairly accurate predictions for a large set of experiments that used concurrent-chain procedures. One advantage of the hyperbolic value-added model is that it is derived from a simpler model that makes accurate predictions for many experiments using discrete-trial adjusting-delay procedures. Some results favor the hyperbolic value-added model and delay-reduction theory over the contextual-choice model, but more data are needed from choice situations for which the models make distinctly different predictions.

  1. Modeling one-choice and two-choice driving tasks.

    PubMed

    Ratcliff, Roger

    2015-08-01

    An experiment is presented in which subjects were tested on both one-choice and two-choice driving tasks and on non-driving versions of them. Diffusion models for one- and two-choice tasks were successful in extracting model-based measures from the response time and accuracy data. These include measures of the quality of the information from the stimuli that drove the decision process (drift rate in the model), the time taken up by processes outside the decision process and, for the two-choice model, the speed/accuracy decision criteria that subjects set. Drift rates were only marginally different between the driving and non-driving tasks, indicating that nearly the same information was used in the two kinds of tasks. The tasks differed in the time taken up by other processes, reflecting the difference between them in response processing demands. Drift rates were significantly correlated across the two two-choice tasks showing that subjects that performed well on one task also performed well on the other task. Nondecision times were correlated across the two driving tasks, showing common abilities on motor processes across the two tasks. These results show the feasibility of using diffusion modeling to examine decision making in driving and so provide for a theoretical examination of factors that might impair driving, such as extreme aging, distraction, sleep deprivation, and so on.

  2. Kinetics of Aggregation with Choice

    DOE PAGES

    Ben-Naim, Eli; Krapivsky, Paul

    2016-12-01

    Here we generalize the ordinary aggregation process to allow for choice. In ordinary aggregation, two random clusters merge and form a larger aggregate. In our implementation of choice, a target cluster and two candidate clusters are randomly selected and the target cluster merges with the larger of the two candidate clusters.We study the long-time asymptotic behavior and find that as in ordinary aggregation, the size density adheres to the standard scaling form. However, aggregation with choice exhibits a number of different features. First, the density of the smallest clusters exhibits anomalous scaling. Second, both the small-size and the large-size tailsmore » of the density are overpopulated, at the expense of the density of moderate-size clusters. Finally, we also study the complementary case where the smaller candidate cluster participates in the aggregation process and find an abundance of moderate clusters at the expense of small and large clusters. Additionally, we investigate aggregation processes with choice among multiple candidate clusters and a symmetric implementation where the choice is between two pairs of clusters.« less

  3. Kinetics of Aggregation with Choice

    SciTech Connect

    Ben-Naim, Eli; Krapivsky, Paul

    2016-12-01

    Here we generalize the ordinary aggregation process to allow for choice. In ordinary aggregation, two random clusters merge and form a larger aggregate. In our implementation of choice, a target cluster and two candidate clusters are randomly selected and the target cluster merges with the larger of the two candidate clusters.We study the long-time asymptotic behavior and find that as in ordinary aggregation, the size density adheres to the standard scaling form. However, aggregation with choice exhibits a number of different features. First, the density of the smallest clusters exhibits anomalous scaling. Second, both the small-size and the large-size tails of the density are overpopulated, at the expense of the density of moderate-size clusters. Finally, we also study the complementary case where the smaller candidate cluster participates in the aggregation process and find an abundance of moderate clusters at the expense of small and large clusters. Additionally, we investigate aggregation processes with choice among multiple candidate clusters and a symmetric implementation where the choice is between two pairs of clusters.

  4. Semiparametric Thurstonian Models for Recurrent Choices: A Bayesian Analysis

    ERIC Educational Resources Information Center

    Ansari, Asim; Iyengar, Raghuram

    2006-01-01

    We develop semiparametric Bayesian Thurstonian models for analyzing repeated choice decisions involving multinomial, multivariate binary or multivariate ordinal data. Our modeling framework has multiple components that together yield considerable flexibility in modeling preference utilities, cross-sectional heterogeneity and parameter-driven…

  5. Mechanisms of Individual Differences in Impulsive and Risky Choice in Rats.

    PubMed

    Kirkpatrick, Kimberly; Marshall, Andrew T; Smith, Aaron P

    2015-01-01

    Individual differences in impulsive and risky choice are key risk factors for a variety of maladaptive behaviors such as drug abuse, gambling, and obesity. In our rat model, ordered individual differences are stable across choice parameters, months of testing, and span a broad spectrum, suggesting that rats, like humans, exhibit trait-level impulsive and risky choice behaviors. In addition, impulsive and risky choices are highly correlated, suggesting a degree of correlation between these two traits. An examination of the underlying cognitive mechanisms has suggested an important role for timing processes in impulsive choice. In addition, in an examination of genetic factors in impulsive choice, the Lewis rat strain emerged as a possible animal model for studying disordered impulsive choice, with this strain demonstrating deficient delay processing. Early rearing environment also affected impulsive behaviors, with rearing in an enriched environment promoting adaptable and more self-controlled choices. The combined results with impulsive choice suggest an important role for timing and reward sensitivity in moderating impulsive behaviors. Relative reward valuation also affects risky choice, with manipulation of objective reward value (relative to an alternative reference point) resulting in loss chasing behaviors that predicted overall risky choice behaviors. The combined results are discussed in relation to domain-specific versus domain-general subjective reward valuation processes and the potential neural substrates of impulsive and risky choice.

  6. Mechanisms of Individual Differences in Impulsive and Risky Choice in Rats

    PubMed Central

    Kirkpatrick, Kimberly; Marshall, Andrew T.; Smith, Aaron P.

    2016-01-01

    Individual differences in impulsive and risky choice are key risk factors for a variety of maladaptive behaviors such as drug abuse, gambling, and obesity. In our rat model, ordered individual differences are stable across choice parameters, months of testing, and span a broad spectrum, suggesting that rats, like humans, exhibit trait-level impulsive and risky choice behaviors. In addition, impulsive and risky choices are highly correlated, suggesting a degree of correlation between these two traits. An examination of the underlying cognitive mechanisms has suggested an important role for timing processes in impulsive choice. In addition, in an examination of genetic factors in impulsive choice, the Lewis rat strain emerged as a possible animal model for studying disordered impulsive choice, with this strain demonstrating deficient delay processing. Early rearing environment also affected impulsive behaviors, with rearing in an enriched environment promoting adaptable and more self-controlled choices. The combined results with impulsive choice suggest an important role for timing and reward sensitivity in moderating impulsive behaviors. Relative reward valuation also affects risky choice, with manipulation of objective reward value (relative to an alternative reference point) resulting in loss chasing behaviors that predicted overall risky choice behaviors. The combined results are discussed in relation to domain-specific versus domain-general subjective reward valuation processes and the potential neural substrates of impulsive and risky choice. PMID:27695580

  7. Suboptimal choice behavior by pigeons.

    PubMed

    Stagner, Jessica P; Zentall, Thomas R

    2010-06-01

    Contrary to the law of effect and optimal foraging theory, pigeons show suboptimal choice behavior by choosing an alternative that provides 20% reinforcement over another that provides 50% reinforcement. They choose the 20% reinforcement alternative--in which 20% of the time, that choice results in a stimulus that always predicts reinforcement, and 80% of the time, it results in another stimulus that predicts its absence--rather than the 50% reinforcement alternative, which results in one of two stimuli, each of which predicts reinforcement 50% of the time. This choice behavior may be related to suboptimal human monetary gambling behavior, because in both cases, the organism overemphasizes the infrequent occurrence of the winning event and underemphasizes the more frequent occurrence of the losing event.

  8. Does health affect portfolio choice?

    PubMed

    Love, David A; Smith, Paul A

    2010-12-01

    A number of recent studies find that poor health is empirically associated with a safer portfolio allocation. It is difficult to say, however, whether this relationship is truly causal. Both health status and portfolio choice are influenced by unobserved characteristics such as risk attitudes, impatience, information, and motivation, and these unobserved factors, if not adequately controlled for, can induce significant bias in the estimates of asset demand equations. Using the 1992-2006 waves of the Health and Retirement Study, we investigate how much of the connection between health and portfolio choice is causal and how much is due to the effects of unobserved heterogeneity. Accounting for unobserved heterogeneity with fixed effects and correlated random effects models, we find that health does not appear to significantly affect portfolio choice among single households. For married households, we find a small effect (about 2-3 percentage points) from being in the lowest of five self-reported health categories.

  9. Articulatory Parameters.

    ERIC Educational Resources Information Center

    Ladefoged, Peter

    1980-01-01

    Summarizes the 16 parameters hypothesized to be necessary and sufficient for linguistic phonetic specifications. Suggests seven parameters affecting tongue shapes, three determining the positions of the lips, one controlling the position of the velum, four varying laryngeal actions, and one controlling respiratory activity. (RL)

  10. Foundation doctors career choice and factors influencing career choice.

    PubMed

    Wiener-Ogilvie, Sharon; Begg, Drummond; Dixon, Guy

    2015-11-01

    This study is seeking to establish the factors influencing foundation doctors' decision-making when applying for speciality training. A questionnaire was sent to all foundation doctors in Scotland (n = 1602, response rate 34%) asking them about their career intention in relation to General Practice, whether they received career advice and the extent to which certain factors influenced their career choice. For the majority of trainees, General Practice was not their first choice but just under half were considering it as a career. There were significant differences in career choices between the four Scottish regions and between the medical schools, with a greater proportion of those who studied in Aberdeen and Dundee Medical Schools opting for a career in General Practice. Undergraduate GP placement was reported as the strongest influence in favour of a career in General Practice followed by discussion with family and friends and discussion with speciality trainees. There were differences between medical schools in the way hospital placements, General Practice placements and role models influenced career choices. Career advice on General Practice was reported to be less available and more difficult to find.

  11. Flooring choices for newborn ICUs.

    PubMed

    White, R D

    2007-12-01

    Floors are a major element of newborn intensive care unit (NICU) construction. They provide visual cues, sound control, and with certain materials, some degree of physical comfort for workers. Flooring materials may entail a significant cost for installation and upkeep and can have substantial ecological impact, both in the choice of the flooring itself, as well as the substances used to clean it. In this article the important aspects to consider for each factor are explored and recommendations are offered for appropriate choices in various NICU areas.

  12. A priori and a posteriori approaches for finding genes of evolutionary interest in non-model species: osmoregulatory genes in the kidney transcriptome of the desert rodent Dipodomys spectabilis (banner-tailed kangaroo rat).

    PubMed

    Marra, Nicholas J; Eo, Soo Hyung; Hale, Matthew C; Waser, Peter M; DeWoody, J Andrew

    2012-12-01

    One common goal in evolutionary biology is the identification of genes underlying adaptive traits of evolutionary interest. Recently next-generation sequencing techniques have greatly facilitated such evolutionary studies in species otherwise depauperate of genomic resources. Kangaroo rats (Dipodomys sp.) serve as exemplars of adaptation in that they inhabit extremely arid environments, yet require no drinking water because of ultra-efficient kidney function and osmoregulation. As a basis for identifying water conservation genes in kangaroo rats, we conducted a priori bioinformatics searches in model rodents (Mus musculus and Rattus norvegicus) to identify candidate genes with known or suspected osmoregulatory function. We then obtained 446,758 reads via 454 pyrosequencing to characterize genes expressed in the kidney of banner-tailed kangaroo rats (Dipodomys spectabilis). We also determined candidates a posteriori by identifying genes that were overexpressed in the kidney. The kangaroo rat sequences revealed nine different a priori candidate genes predicted from our Mus and Rattus searches, as well as 32 a posteriori candidate genes that were overexpressed in kidney. Mutations in two of these genes, Slc12a1 and Slc12a3, cause human renal diseases that result in the inability to concentrate urine. These genes are likely key determinants of physiological water conservation in desert rodents.

  13. More Choice Isn't Always Better

    ERIC Educational Resources Information Center

    Schuller, Tom

    2012-01-01

    Choice is important to everyone, for one's identity as well as one's material satisfaction. Everyone has choices, but even the head of state's choices are constrained. In recent years choice has risen up the political agenda in the UK. It has become a key component of the drive to reform public services such as health and education. The…

  14. School Choice in Less Populated Areas.

    ERIC Educational Resources Information Center

    Hammond, Tom; Dennison, Bill

    1995-01-01

    Discusses a parental choice case involving a rural (British) school with a 13+ transfer age to determine parents' use of the open enrollment system, effects of transport policy on exercising parental choice, quality of information provided, and factors influencing choice. Transportation was problematic. Four choice factors stood out: teacher…

  15. The Surprising Consensus on School Choice.

    ERIC Educational Resources Information Center

    Greene, Jay P.

    2001-01-01

    Discusses whether school choice benefits students who do and do not receive vouchers, noting how choice affects integration and democratic ideals. Overall, there are important benefits for families participating in choice programs. Choice does not cream off the best students. Educational vouchers may influence public schools to improve. Private…

  16. School Choice in an Established Market.

    ERIC Educational Resources Information Center

    Gorard, Stephen

    This book examines the trend toward markets in UK schools by outlining the varied economic and political arguments both for and against increased parental choice. It describes how choice actually takes place--including when the choice takes place, who has the final say, how many schools are considered, and which choice criteria are reported. One…

  17. The Additive Effects of Choice and Control.

    ERIC Educational Resources Information Center

    Karbowski, Joseph; And Others

    In separate research studies, students who were given a choice of learning materials or who had control over aversive noise, demonstrated higher motivation and better task performance. To investigate the additive effects of choice and control on perception of control, 80 male and female college students participated in a 2 (choice vs. no-choice) X…

  18. A priori and a posteriori investigations for developing large eddy simulations of multi-species turbulent mixing under high-pressure conditions

    SciTech Connect

    Borghesi, Giulio; Bellan, Josette

    2015-03-15

    , and the filtered species mass fluxes. Improved models were developed based on a scale-similarity approach and were found to perform considerably better than the classical ones. These improved models were also assessed in an a posteriori study. Different combinations of the standard models and the improved ones were tested. At the relatively small Reynolds numbers achievable in DNS and at the relatively small filter widths used here, the standard models for the filtered pressure, the filtered heat flux, and the filtered species fluxes were found to yield accurate results for the morphology of the large-scale structures present in the flow. Analysis of the temporal evolution of several volume-averaged quantities representative of the mixing layer growth, and of the cross-stream variation of homogeneous-plane averages and second-order correlations, as well as of visualizations, indicated that the models performed equivalently for the conditions of the simulations. The expectation is that at the much larger Reynolds numbers and much larger filter widths used in practical applications, the improved models will have much more accurate performance than the standard one.

  19. Methodological Individualism and Public Choice.

    ERIC Educational Resources Information Center

    Sproule-Jones, Mark, Ed.

    1984-01-01

    The economic reasoning that individuals use in making public choices regarding politics, society, and the economy is examined in these essays. All of the essays set the agenda for addressing the perplexing problems of understanding individual behavior in relation to the behavior of others. (RM)

  20. Moral Dimensions of Curriculum Choices.

    ERIC Educational Resources Information Center

    MacMillan, C. J. B.

    This paper argues that just as subject matter is inherently value-laden, educators should not feel trepidation about morally justifying their criteria for choosing curricula to be taught in the classroom. It recommends that true "moral" choices should be made on the bases of relevance to student experiences; moral propriety of subject matter…

  1. Accommodations for Multiple Choice Tests

    ERIC Educational Resources Information Center

    Trammell, Jack

    2011-01-01

    Students with learning or learning-related disabilities frequently struggle with multiple choice assessments due to difficulty discriminating between items, filtering out distracters, and framing a mental best answer. This Practice Brief suggests accommodations and strategies that disability service providers can utilize in conjunction with…

  2. No Easy Road to Choice

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2008-01-01

    In the new educational landscape of New Orleans--where public school choice is a fundamental element--pounding the pavement to drum up students has become a familiar pursuit. Proponents say a central idea of the education system that has emerged since Hurricane Katrina hit in 2005 is to provide a diverse array of high-quality school options, with…

  3. Dimensions of Charter School Choice

    ERIC Educational Resources Information Center

    Holyoke, Thomas T.

    2008-01-01

    In this paper I develop indices capturing business/market and nonprofit/mission characteristics of charter schools that can be used to explain many of their observed operational and political choices. This improves on earlier research using only a binary variable classifying charter schools as market or mission rather than letting them take on…

  4. Educational Choice and Educational Space

    ERIC Educational Resources Information Center

    Thomson, Kathleen Sonia

    2016-01-01

    This dissertation entitled "Educational choice and educational space" aims to explore the confluence of constructed space and geographic space using a supply-side context for New Zealand's public school system of quasi-open enrollment. In Part I, New Zealand's state and state-integrated school system across four urban areas is analyzed…

  5. Choice in P-16 Initiatives

    ERIC Educational Resources Information Center

    Meyer, Rhonda

    2008-01-01

    A system of PK-16 parental choice would look much more like the current situation in early education and in postsecondary education than like the system of K-12 neighborhood schools. The changes required would provide more options for a tailored or customized educational experience for each child than those now offered by the K-12 public school…

  6. Young Adults' Choices for 2008

    ERIC Educational Resources Information Center

    Journal of Adolescent & Adult Literacy, 2008

    2008-01-01

    This article presents annotations of 30 trade books on the 2008 list of Young Adults' Choices that are the result of voting by students in five different regions of the United States. Trade books (books other than textbooks) published in 2006 were submitted by more than 50 publishers. Each book had to have at least two positive reviews from…

  7. Improving Multiple-Choice Questions

    ERIC Educational Resources Information Center

    Torres, Cristina; Lopes, Ana Paula; Babo, Lurdes; Azevedo, Jose

    2011-01-01

    A MC (multiple-choice) question can be defined as a question in which students are asked to select one alternative from a given set of alternatives in response to a question stem. The objective of this paper is to analyse if MC questions may be considered as an interesting alternative for assessing knowledge, particularly in the mathematics area,…

  8. Students' Choices and Moral Growth

    ERIC Educational Resources Information Center

    Goodman, Joan F.

    2006-01-01

    Can schools encourage children to become independent moral decision-makers, maintaining controlled environments suitable to instructing large numbers of children? Two opposing responses are reviewed: one holds that the road to morality is through discipline and obedience, the other through children's experimentation and choice-making.…

  9. Coming Around on School Choice.

    ERIC Educational Resources Information Center

    Viteritti, Joseph P.

    2002-01-01

    Asserts that opponent's predictions that school choice would result in mass exodus of students and a disparate impact on public schools have failed to materialize. Argues that disadvantaged students, especially blacks, in inner-city schools are the principal beneficiaries of voucher programs. (Contains 13 references.) (PKP)

  10. Impulsive Choice and Workplace Safety: A New Area of Inquiry for Research in Occupational Settings

    ERIC Educational Resources Information Center

    Reynolds, Brady; Schiffbauer, Ryan M.

    2004-01-01

    A conceptual argument is presented for the relevance of behavior-analytic research on impulsive choice to issues of occupational safety and health. Impulsive choice is defined in terms of discounting, which is the tendency for the value of a commodity to decrease as a function of various parameters (e.g., having to wait or expend energy to receive…

  11. PEER REVIEW FOR THE CONSUMER VEHICLE CHOICE ...

    EPA Pesticide Factsheets

    The U.S. Environmental Protection Agency’s (EPA) Office of Transportation and Air Quality (OTAQ) has recently sponsored the development of a Consumer Vehicle Choice Model (CVCM) by the Oak Ridge National Laboratory (ORNL). The specification by OTAQ to ORNL for consumer choice model development was to develop a Nested Multinomial Logit (NMNL) or other appropriate model capable of estimating the consumer surplus impacts and the sales mix effects of greenhouse gas (GHG) emission standards. The CVCM will use output from the EPA’s Optimization Model for reducing Emissions of Greenhouse gases from Automobiles (OMEGA), including changes in retail price equivalents, changes in fuel economy, and changes in emissions, to estimate these impacts. In addition, the CVCM will accept approximately 60 vehicle types, with the flexibility to function with fewer or more vehicle types, and will use a 15 year planning horizon, matching the OMEGA parameters. It will be calibrated to baseline sales projection data provided by the EPA and will include a buy/no-buy option to simulate the possibility that consumers will choose to keep their old vehicle or to buy a used vehicle. To support EPA's future assessment of potential light duty greenhouse gas standards

  12. [The choice of a pediatric anesthesia ventilator].

    PubMed

    Kern, D; Larcher, C; Cottron, N; Ait Aissa, D; Fesseau, R; Alacoque, X; Delort, F; Masquère, P; Agnès, E; Visnadi, G; Fourcade, O

    2013-12-01

    The technology of anesthesia ventilators has substantially progressed during last years. The choice of a pediatric anesthesia ventilator needs to be led by multiple parameters: requirement, technical (pneumatic performance, velocity of halogenated or oxygen delivery), cost (purchase, in operation, preventive and curative maintenance), reliability, ergonomy, upgradability, and compatibility. The demonstration of the interest of pressure support mode during maintenance of spontaneous ventilation anesthesia makes this mode essential in pediatrics. In contrast, the financial impact of target controlled inhalation of halogenated has not be studied in pediatrics. Paradoxically, complex and various available technologies had not been much prospectively studied. Anesthesia ventilators performances in pediatrics need to be clarified in further clinical and bench test studies.

  13. Breech presentation: increasing maternal choice.

    PubMed

    Tiran, Denise

    2004-11-01

    Pregnant women with a third trimester breech presentation are almost invariably offered Caesarean section as the mode of delivery of first choice, especially when external version has failed to turn the fetus to cephalic. However, increasingly women are resorting to alternatives, to avoid either operative delivery or manipulative intervention in late pregnancy. This paper reviews some of the options for women with breech presentation, focusing especially on integrating these options into conventional maternity care.

  14. How suboptimal is suboptimal choice?

    PubMed

    Hinnenkamp, Jay E; Shahan, Timothy A; Madden, Gregory J

    2017-01-01

    In a frequently used suboptimal-choice procedure pigeons choose between an alternative that delivers three food pellets with p = 1.0 and an alternative that delivers ten pellets with p = 0.2. Because pigeons reliably choose the probabilistic (suboptimal) alternative, the procedure has been proposed as a nonhuman analog of human gambling. The present experiments were conducted to evaluate two potential threats to the validity of this procedure. Experiments 1 and 2 evaluated if pigeons obtained food at a lower unit price (i.e., pecks per pellet) on the suboptimal alternative than on the optimal alternative. When pigeons worked under this suboptimal procedure they all preferred the suboptimal alternative despite some pigeons paying a higher price for food on that alternative. In Experiment 2, when the unit price ratio more closely approximated the inverse of the expected value ratio, pigeons continued to prefer the suboptimal alternative despite its economic suboptimality. Experiment 3 evaluated if, in accord with the string-theory of gambling, the valuation of the suboptimal alternative was increased when pigeons misattributed a subset of the suboptimal no-food trials to the optimal alternative. When trial sequences were arranged to minimize these possible attribution errors, pigeons still preferred the suboptimal alternative. These data remove two threats to the validity of the suboptimal choice procedure; threats that would have suggested that suboptimal choice reflects economic maximization.

  15. Street choice logit model for visitors in shopping districts.

    PubMed

    Kawada, Ko; Yamada, Takashi; Kishimoto, Tatsuya

    2014-09-01

    In this study, we propose two models for predicting people's activity. The first model is the pedestrian distribution prediction (or postdiction) model by multiple regression analysis using space syntax indices of urban fabric and people distribution data obtained from a field survey. The second model is a street choice model for visitors using multinomial logit model. We performed a questionnaire survey on the field to investigate the strolling routes of 46 visitors and obtained a total of 1211 street choices in their routes. We proposed a utility function, sum of weighted space syntax indices, and other indices, and estimated the parameters for weights on the basis of maximum likelihood. These models consider both street networks, distance from destination, direction of the street choice and other spatial compositions (numbers of pedestrians, cars, shops, and elevation). The first model explains the characteristics of the street where many people tend to walk or stay. The second model explains the mechanism underlying the street choice of visitors and clarifies the differences in the weights of street choice parameters among the various attributes, such as gender, existence of destinations, number of people, etc. For all the attributes considered, the influences of DISTANCE and DIRECTION are strong. On the other hand, the influences of Int.V, SHOPS, CARS, ELEVATION, and WIDTH are different for each attribute. People with defined destinations tend to choose streets that "have more shops, and are wider and lower". In contrast, people with undefined destinations tend to choose streets of high Int.V. The choice of males is affected by Int.V, SHOPS, WIDTH (positive) and CARS (negative). Females prefer streets that have many shops, and couples tend to choose downhill streets. The behavior of individual persons is affected by all variables. The behavior of people visiting in groups is affected by SHOP and WIDTH (positive).

  16. Grading School Choice: Evaluating School Choice Programs by the Friedman Gold Standard. School Choice Issues in Depth

    ERIC Educational Resources Information Center

    Enlow, Robert C.

    2008-01-01

    In 2004, The Friedman Foundation for Educational Choice published a report titled "Grading Vouchers: Ranking America's School Choice Programs." Its purpose was to measure every existing school choice program against the gold standard set by Milton and Rose Friedman: that the most effective way to improve K-12 education and thus ensure a stable…

  17. Making Healthy Choices at Fast Food Restaurants

    MedlinePlus

    ... Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight Loss and Diet Plans Nutrients and Nutritional ... Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight Loss and Diet Plans Nutrients and Nutritional ...

  18. How the twain can meet: Prospect theory and models of heuristics in risky choice.

    PubMed

    Pachur, Thorsten; Suter, Renata S; Hertwig, Ralph

    2017-03-01

    Two influential approaches to modeling choice between risky options are algebraic models (which focus on predicting the overt decisions) and models of heuristics (which are also concerned with capturing the underlying cognitive process). Because they rest on fundamentally different assumptions and algorithms, the two approaches are usually treated as antithetical, or even incommensurable. Drawing on cumulative prospect theory (CPT; Tversky & Kahneman, 1992) as the currently most influential instance of a descriptive algebraic model, we demonstrate how the two modeling traditions can be linked. CPT's algebraic functions characterize choices in terms of psychophysical (diminishing sensitivity to probabilities and outcomes) as well as psychological (risk aversion and loss aversion) constructs. Models of heuristics characterize choices as rooted in simple information-processing principles such as lexicographic and limited search. In computer simulations, we estimated CPT's parameters for choices produced by various heuristics. The resulting CPT parameter profiles portray each of the choice-generating heuristics in psychologically meaningful ways-capturing, for instance, differences in how the heuristics process probability information. Furthermore, CPT parameters can reflect a key property of many heuristics, lexicographic search, and track the environment-dependent behavior of heuristics. Finally, we show, both in an empirical and a model recovery study, how CPT parameter profiles can be used to detect the operation of heuristics. We also address the limits of CPT's ability to capture choices produced by heuristics. Our results highlight an untapped potential of CPT as a measurement tool to characterize the information processing underlying risky choice.

  19. A Framework for Choice Remedy Litigation

    ERIC Educational Resources Information Center

    Bolick, Clint

    2008-01-01

    Although school choice proponents have generally been on the offensive in legislative arenas over the past 2 decades, they have played almost constant defense in the judiciary, seeking to prevent courts from undoing school choice programs. Opponents typically wield state constitutional provisions against school choice programs. Properly construed,…

  20. Public School Choice: Searching for Direction.

    ERIC Educational Resources Information Center

    Glenn, Charles L.

    1998-01-01

    If high- and middle-income parents make disproportionate use of school choice through residential and private school decisions, lower-income parents are more strongly represented in public school choices, many related to desegregation options. Magnet schools and voucher systems benefit those who hear about them. Universal controlled choice has had…

  1. School Choice Acceptance: An Exploratory Explication

    ERIC Educational Resources Information Center

    Koven, Steven G.; Khan, Mobin

    2014-01-01

    School choice is presented by some as a panacea to the challenges facing education in the United States. Acceptance of choice as a solution, however, is far from universal. This article examines two possible contributors to choice adoption: ideology and political culture. Political culture was found to better explain the complex phenomenon of…

  2. Discrepancy between Snack Choice Intentions and Behavior

    ERIC Educational Resources Information Center

    Weijzen, Pascalle L. G.; de Graaf, Cees; Dijksterhuis, Garmt B.

    2008-01-01

    Objective: To investigate dietary constructs that affect the discrepancy between intentioned and actual snack choice. Design: Participants indicated their intentioned snack choice from a set of 4 snacks (2 healthful, 2 unhealthful). One week later, they actually chose a snack from the same set. Within 1 week after the actual choice, they completed…

  3. Vocational Choice: A Decision Making Perspective

    ERIC Educational Resources Information Center

    Sauermann, Henry

    2005-01-01

    We propose a model of vocational choice that can be used for analyzing and guiding the decision processes underlying career and job choices. Our model is based on research in behavioral decision making (BDM), in particular the choice goals framework developed by Bettman, Luce, and Payne (1998). The basic model involves two major processes. First,…

  4. School Choice as a Bounded Ideal

    ERIC Educational Resources Information Center

    Ben-Porath, Sigal R.

    2009-01-01

    School choice is most often viewed through the lens of provision: most of the debate on the issue searches for desirable ways to offer vouchers, scholarships or other tools that provides choice as a way to achieve equality and/or freedom. This paper focuses on the consumer side of school choice, and utilises behavioural economics as well as…

  5. Choice: The Route to Community Control?

    ERIC Educational Resources Information Center

    Margonis, Frank; Parker, Laurence

    1999-01-01

    While school choice offers inner-city parents a means of educating their children well, it represents further deterioration of society's commitment to educating all students. This paper describes: the push for private school choice; parent choice in context (historical context and failures of desegregation); and segregationist strategies and…

  6. Risk and Career Choice: Evidence from Turkey

    ERIC Educational Resources Information Center

    Caner, Asena; Okten, Cagla

    2010-01-01

    In this paper, we examine the college major choice decision in a risk and return framework using university entrance exam data from Turkey. Specifically we focus on the choice between majors with low income risk such as education and health and others with riskier income streams. We use a unique dataset that allows us to control for the choice set…

  7. Pricing effects on food choices.

    PubMed

    French, Simone A

    2003-03-01

    Individual dietary choices are primarily influenced by such considerations as taste, cost, convenience and nutritional value of foods. The current obesity epidemic has been linked to excessive consumption of added sugars and fat, as well as to sedentary lifestyles. Fat and sugar provide dietary energy at very low cost. Food pricing and marketing practices are therefore an essential component of the eating environment. Recent studies have applied economic theories to changing dietary behavior. Price reduction strategies promote the choice of targeted foods by lowering their cost relative to alternative food choices. Two community-based intervention studies used price reductions to promote the increased purchase of targeted foods. The first study examined lower prices and point-of-purchase promotion on sales of lower fat vending machine snacks in 12 work sites and 12 secondary schools. Price reductions of 10%, 25% and 50% on lower fat snacks resulted in an increase in sales of 9%, 39% and 93%, respectively, compared with usual price conditions. The second study examined the impact of a 50% price reduction on fresh fruit and baby carrots in two secondary school cafeterias. Compared with usual price conditions, price reductions resulted in a four-fold increase in fresh fruit sales and a two-fold increase in baby carrot sales. Both studies demonstrate that price reductions are an effective strategy to increase the purchase of more healthful foods in community-based settings such as work sites and schools. Results were generalizable across various food types and populations. Reducing prices on healthful foods is a public health strategy that should be implemented through policy initiatives and industry collaborations.

  8. The PXIE LEBT Design Choices

    SciTech Connect

    Prost, Lionel; Shemyakin, Alexander

    2016-06-01

    Typical front-ends of modern light-ion high-intensity accelerators typically consist of an ion source, a Low Energy Beam Transport (LEBT), a Radiofrequency Quadrupole and a Medium Energy Beam Transport (MEBT), which is followed by the main linac accelerating structures. Over the years, many LEBTs have been designed, constructed and operated very successfully. In this paper, we present the guiding principles and compromises that lead to the design choices of the PXIE LEBT, including the rationale for a beam line that allows un-neutralized transport over a significant portion of the LEBT whether the beam is pulsed or DC.

  9. TAFV Alternative Fuels and Vehicles Choice Model Documentation

    SciTech Connect

    Greene, D.L.

    2001-07-27

    A model for predicting choice of alternative fuel and among alternative vehicle technologies for light-duty motor vehicles is derived. The nested multinomial logit (NML) mathematical framework is used. Calibration of the model is based on information in the existing literature and deduction based on assuming a small number of key parameters, such as the value of time and discount rates. A spreadsheet model has been developed for calibration and preliminary testing of the model.

  10. Bayesian Parameter Estimation and Segmentation in the Multi-Atlas Random Orbit Model.

    PubMed

    Tang, Xiaoying; Oishi, Kenichi; Faria, Andreia V; Hillis, Argye E; Albert, Marilyn S; Mori, Susumu; Miller, Michael I

    2013-01-01

    This paper examines the multiple atlas random diffeomorphic orbit model in Computational Anatomy (CA) for parameter estimation and segmentation of subcortical and ventricular neuroanatomy in magnetic resonance imagery. We assume that there exist multiple magnetic resonance image (MRI) atlases, each atlas containing a collection of locally-defined charts in the brain generated via manual delineation of the structures of interest. We focus on maximum a posteriori estimation of high dimensional segmentations of MR within the class of generative models representing the observed MRI as a conditionally Gaussian random field, conditioned on the atlas charts and the diffeomorphic change of coordinates of each chart that generates it. The charts and their diffeomorphic correspondences are unknown and viewed as latent or hidden variables. We demonstrate that the expectation-maximization (EM) algorithm arises naturally, yielding the likelihood-fusion equation which the a posteriori estimator of the segmentation labels maximizes. The likelihoods being fused are modeled as conditionally Gaussian random fields with mean fields a function of each atlas chart under its diffeomorphic change of coordinates onto the target. The conditional-mean in the EM algorithm specifies the convex weights with which the chart-specific likelihoods are fused. The multiple atlases with the associated convex weights imply that the posterior distribution is a multi-modal representation of the measured MRI. Segmentation results for subcortical and ventricular structures of subjects, within populations of demented subjects, are demonstrated, including the use of multiple atlases across multiple diseased groups.

  11. Choice as a Global Language in Local Practice: A Mixed Model of School Choice in Taiwan

    ERIC Educational Resources Information Center

    Mao, Chin-Ju

    2015-01-01

    This paper uses school choice policy as an example to demonstrate how local actors adopt, mediate, translate, and reformulate "choice" as neo-liberal rhetoric informing education reform. Complex processes exist between global policy about school choice and the local practice of school choice. Based on the theoretical sensibility of…

  12. The determinants of food choice.

    PubMed

    Leng, Gareth; Adan, Roger A H; Belot, Michele; Brunstrom, Jeffrey M; de Graaf, Kees; Dickson, Suzanne L; Hare, Todd; Maier, Silvia; Menzies, John; Preissl, Hubert; Reisch, Lucia A; Rogers, Peter J; Smeets, Paul A M

    2016-12-01

    Health nudge interventions to steer people into healthier lifestyles are increasingly applied by governments worldwide, and it is natural to look to such approaches to improve health by altering what people choose to eat. However, to produce policy recommendations that are likely to be effective, we need to be able to make valid predictions about the consequences of proposed interventions, and for this, we need a better understanding of the determinants of food choice. These determinants include dietary components (e.g. highly palatable foods and alcohol), but also diverse cultural and social pressures, cognitive-affective factors (perceived stress, health attitude, anxiety and depression), and familial, genetic and epigenetic influences on personality characteristics. In addition, our choices are influenced by an array of physiological mechanisms, including signals to the brain from the gastrointestinal tract and adipose tissue, which affect not only our hunger and satiety but also our motivation to eat particular nutrients, and the reward we experience from eating. Thus, to develop the evidence base necessary for effective policies, we need to build bridges across different levels of knowledge and understanding. This requires experimental models that can fill in the gaps in our understanding that are needed to inform policy, translational models that connect mechanistic understanding from laboratory studies to the real life human condition, and formal models that encapsulate scientific knowledge from diverse disciplines, and which embed understanding in a way that enables policy-relevant predictions to be made. Here we review recent developments in these areas.

  13. Anterior Cruciate Ligament Graft Choices

    PubMed Central

    Macaulay, Alec A.; Perfetti, Dean C.; Levine, William N.

    2012-01-01

    Context: Reconstruction of the anterior cruciate ligament (ACL) is a common surgical procedure; however, there is no consensus to what the best graft option is to replace the injured ACL. The main options available consist of allografts and autografts, which include patellar tendon, hamstring tendon, and quadriceps tendon autografts. Evidence Acquisition: The PubMed database was searched in August 2010 for English-language articles pertaining to ACL grafts. Results: Postoperative outcome variables were analyzed to determine similarities and differences among the different graft options. These variables include stability, strength, function, return to sports, patient satisfaction, complications, and cost. Conclusions: Both allografts and the 3 main options for autografts can provide excellent results in ACL reconstruction and lead to a high percentage of satisfied patients. However, differences exist among the graft choices. Both the similarities and the differences are important to discuss with a patient who will be undergoing ACL reconstruction so that he or she has the best information available when making a choice of graft. PMID:23016071

  14. Prospect theory based estimation of drivers' risk attitudes in route choice behaviors.

    PubMed

    Zhou, Lizhen; Zhong, Shiquan; Ma, Shoufeng; Jia, Ning

    2014-12-01

    This paper applied prospect theory (PT) to describe drivers' route choice behavior under Variable Message Sign (VMS), which presented visual traffic information to assist them to make route choice decisions. A quite rich empirical data from questionnaire and field spot was used to estimate parameters of PT. In order to make the parameters more realistic with drivers' attitudes, they were classified into different types by significant factors influencing their behaviors. Based on the travel time distribution of alternative routes and route choice results from questionnaire, the parameterized value function of each category was figured out, which represented drivers' risk attitudes and choice characteristics. The empirical verification showed that the estimates were acceptable and effective. The result showed drivers' risk attitudes and route choice characteristics could be captured by PT under real-time information shown on VMS. For practical application, once drivers' route choice characteristics and parameters were identified, their route choice behavior under different road conditions could be predicted accurately, which was the basis of traffic guidance measures formulation and implementation for targeted traffic management. Moreover, the heterogeneous risk attitudes among drivers should be considered when releasing traffic information and regulating traffic flow.

  15. Supergranular Parameters

    NASA Astrophysics Data System (ADS)

    Udayashankar, Paniveni

    2016-07-01

    I study the complexity of supergranular cells using intensity patterns from Kodaikanal solar observatory. The chaotic and turbulent aspect of the solar supergranulation can be studied by examining the interrelationships amongst the parameters characterizing supergranular cells namely size, horizontal flow field, lifetime and physical dimensions of the cells and the fractal dimension deduced from the size data. The findings are supportive of Kolmogorov's theory of turbulence. The Data consists of visually identified supergranular cells, from which a fractal dimension 'D' for supergranulation is obtained according to the relation P α AD/2 where 'A' is the area and 'P' is the perimeter of the supergranular cells. I find a fractal dimension close to about 1.3 which is consistent with that for isobars and suggests a possible turbulent origin. The cell circularity shows a dependence on the perimeter with a peak around (1.1-1.2) x 105 m. The findings are supportive of Kolmogorov's theory of turbulence.

  16. The choice of practice location

    PubMed Central

    Butler, J. R.; Knight, Rose

    1975-01-01

    A ten per cent sample survey of all general practitioners in England and Wales in 1969-70 included two questions about the choice of practice location. The most common reasons given were the absence of any real alternatives (in the immediate post-war period), the influence of family or friends, the existence of medical contacts in the area, and favourable points about the practice itself. In considering possible future moves, general practitioners would pay closest attention to the educational facilities of an area, its rural or coastal location, its social and cultural amenities, and the practice conditions. The conclusion is drawn that financial incentives are unlikely to contribute much towards a more equal distribution of general-practitioner manpower. More thought should be given to recruitment to the medical profession in under-doctored areas through the development of the highest professional standards and facilities in such places. PMID:1195223

  17. Parameter Optimization of a Box and a Three-Dimensional Ocean Carbon Cycle Model Using the Adjoint Method: What Can We Learn?

    NASA Astrophysics Data System (ADS)

    Tjiputra, J.; Winguth, A.

    2005-12-01

    A data assimilation technique is used to optimize marine ecosystem parameters that constraining carbon fluxes in a three-dimensional ocean carbon cycle model. An identical twin experiment is able to produce an a posteriori parameter set with significantly reduced model-data misfit. Error analysis using the Hessian matrix is applied to provide detailed information on the sensitivity of different parameters. Parameters associated with zooplankton grazing and phytoplankton growth reveal to be most sensitive with respect to surface chlorophyll concentration. In order to analyze the sensitivity of these parameters in more detail, biweekly BATS data are compared with a box model as well as with three-dimensional model. Interestingly, when different ocean regions are assimilated separately based on different physical and biogeochemical conditions, regional variation of ecosystem parameters significantly reduces the model-data misfit. Our results also show that certain regions need to have improved ecosystem model formulations in order to reduce the model data-misfit further.

  18. A Simplified Model of Choice Behavior under Uncertainty

    PubMed Central

    Lin, Ching-Hung; Lin, Yu-Kai; Song, Tzu-Jiun; Huang, Jong-Tsun; Chiu, Yao-Chu

    2016-01-01

    The Iowa Gambling Task (IGT) has been standardized as a clinical assessment tool (Bechara, 2007). Nonetheless, numerous research groups have attempted to modify IGT models to optimize parameters for predicting the choice behavior of normal controls and patients. A decade ago, most researchers considered the expected utility (EU) model (Busemeyer and Stout, 2002) to be the optimal model for predicting choice behavior under uncertainty. However, in recent years, studies have demonstrated that models with the prospect utility (PU) function are more effective than the EU models in the IGT (Ahn et al., 2008). Nevertheless, after some preliminary tests based on our behavioral dataset and modeling, it was determined that the Ahn et al. (2008) PU model is not optimal due to some incompatible results. This study aims to modify the Ahn et al. (2008) PU model to a simplified model and used the IGT performance of 145 subjects as the benchmark data for comparison. In our simplified PU model, the best goodness-of-fit was found mostly as the value of α approached zero. More specifically, we retested the key parameters α, λ, and A in the PU model. Notably, the influence of the parameters α, λ, and A has a hierarchical power structure in terms of manipulating the goodness-of-fit in the PU model. Additionally, we found that the parameters λ and A may be ineffective when the parameter α is close to zero in the PU model. The present simplified model demonstrated that decision makers mostly adopted the strategy of gain-stay loss-shift rather than foreseeing the long-term outcome. However, there are other behavioral variables that are not well revealed under these dynamic-uncertainty situations. Therefore, the optimal behavioral models may not have been found yet. In short, the best model for predicting choice behavior under dynamic-uncertainty situations should be further evaluated. PMID:27582715

  19. A Simplified Model of Choice Behavior under Uncertainty.

    PubMed

    Lin, Ching-Hung; Lin, Yu-Kai; Song, Tzu-Jiun; Huang, Jong-Tsun; Chiu, Yao-Chu

    2016-01-01

    The Iowa Gambling Task (IGT) has been standardized as a clinical assessment tool (Bechara, 2007). Nonetheless, numerous research groups have attempted to modify IGT models to optimize parameters for predicting the choice behavior of normal controls and patients. A decade ago, most researchers considered the expected utility (EU) model (Busemeyer and Stout, 2002) to be the optimal model for predicting choice behavior under uncertainty. However, in recent years, studies have demonstrated that models with the prospect utility (PU) function are more effective than the EU models in the IGT (Ahn et al., 2008). Nevertheless, after some preliminary tests based on our behavioral dataset and modeling, it was determined that the Ahn et al. (2008) PU model is not optimal due to some incompatible results. This study aims to modify the Ahn et al. (2008) PU model to a simplified model and used the IGT performance of 145 subjects as the benchmark data for comparison. In our simplified PU model, the best goodness-of-fit was found mostly as the value of α approached zero. More specifically, we retested the key parameters α, λ, and A in the PU model. Notably, the influence of the parameters α, λ, and A has a hierarchical power structure in terms of manipulating the goodness-of-fit in the PU model. Additionally, we found that the parameters λ and A may be ineffective when the parameter α is close to zero in the PU model. The present simplified model demonstrated that decision makers mostly adopted the strategy of gain-stay loss-shift rather than foreseeing the long-term outcome. However, there are other behavioral variables that are not well revealed under these dynamic-uncertainty situations. Therefore, the optimal behavioral models may not have been found yet. In short, the best model for predicting choice behavior under dynamic-uncertainty situations should be further evaluated.

  20. Psychophysics of time perception and intertemporal choice models

    NASA Astrophysics Data System (ADS)

    Takahashi, Taiki; Oono, Hidemi; Radford, Mark H. B.

    2008-03-01

    Intertemporal choice and psychophysics of time perception have been attracting attention in econophysics and neuroeconomics. Several models have been proposed for intertemporal choice: exponential discounting, general hyperbolic discounting (exponential discounting with logarithmic time perception of the Weber-Fechner law, a q-exponential discount model based on Tsallis's statistics), simple hyperbolic discounting, and Stevens' power law-exponential discounting (exponential discounting with Stevens' power time perception). In order to examine the fitness of the models for behavioral data, we estimated the parameters and AICc (Akaike Information Criterion with small sample correction) of the intertemporal choice models by assessing the points of subjective equality (indifference points) at seven delays. Our results have shown that the orders of the goodness-of-fit for both group and individual data were [Weber-Fechner discounting (general hyperbola) > Stevens' power law discounting > Simple hyperbolic discounting > Exponential discounting], indicating that human time perception in intertemporal choice may follow the Weber-Fechner law. Indications of the results for neuropsychopharmacological treatments of addiction and biophysical processing underlying temporal discounting and time perception are discussed.

  1. An organizational model of choice: a theoretical analysis differentiating choice, personal control, and self-determination.

    PubMed

    Williams, S

    1998-11-01

    Individuals experience choice when they select one option from among meaningful alternatives that possess relatively equal attractiveness and some degree of indeterminacy. Choice has been found to influence important psychological and behavioral outcomes. After differentiating among choice, personal control, and self-determination, the author offers a model of choice, with self-determination as the key mechanism regulating how choice influences intrinsic motivation. The model suggests specific types of choice-relevant information that should affect whether choice results in an internal (self-determined) or external (controlled) locus of causality. The individual characteristics of locus of control, self-presentation, self-esteem, and Type A personality are suggested as possible moderators of the effects of choice. Finally, the implications of the choice model for organizations and further areas of research are discussed.

  2. Behavioural social choice: a status report.

    PubMed

    Regenwetter, Michel; Grofman, Bernard; Popova, Anna; Messner, William; Davis-Stober, Clintin P; Cavagnaro, Daniel R

    2009-03-27

    Behavioural social choice has been proposed as a social choice parallel to seminal developments in other decision sciences, such as behavioural decision theory, behavioural economics, behavioural finance and behavioural game theory. Behavioural paradigms compare how rational actors should make certain types of decisions with how real decision makers behave empirically. We highlight that important theoretical predictions in social choice theory change dramatically under even minute violations of standard assumptions. Empirical data violate those critical assumptions. We argue that the nature of preference distributions in electorates is ultimately an empirical question, which social choice theory has often neglected. We also emphasize important insights for research on decision making by individuals. When researchers aggregate individual choice behaviour in laboratory experiments to report summary statistics, they are implicitly applying social choice rules. Thus, they should be aware of the potential for aggregation paradoxes. We hypothesize that such problems may substantially mar the conclusions of a number of (sometimes seminal) papers in behavioural decision research.

  3. Multiple Choice Knapsack Problem: example of planning choice in transportation.

    PubMed

    Zhong, Tao; Young, Rhonda

    2010-05-01

    Transportation programming, a process of selecting projects for funding given budget and other constraints, is becoming more complex as a result of new federal laws, local planning regulations, and increased public involvement. This article describes the use of an integer programming tool, Multiple Choice Knapsack Problem (MCKP), to provide optimal solutions to transportation programming problems in cases where alternative versions of projects are under consideration. In this paper, optimization methods for use in the transportation programming process are compared and then the process of building and solving the optimization problems is discussed. The concepts about the use of MCKP are presented and a real-world transportation programming example at various budget levels is provided. This article illustrates how the use of MCKP addresses the modern complexities and provides timely solutions in transportation programming practice. While the article uses transportation programming as a case study, MCKP can be useful in other fields where a similar decision among a subset of the alternatives is required.

  4. Suboptimal Choice in Pigeons: Stimulus Value Predicts Choice over Frequencies

    PubMed Central

    Bailey, Alexandria R.; Chow, Jonathan J.; Beckmann, Joshua S.; Zentall, Thomas R.

    2016-01-01

    Pigeons have shown suboptimal gambling-like behavior when preferring a stimulus that infrequently signals reliable reinforcement over alternatives that provide greater reinforcement overall. As a mechanism for this behavior, recent research proposed that the stimulus value of alternatives with more reliable signals for reinforcement will be preferred relatively independently of their frequencies. The present study tested this hypothesis using a simplified design of a Discriminative alternative that, 50% of the time, led to either a signal for 100% reinforcement or a blackout period indicative of 0% reinforcement against a Nondiscriminative alternative that always led to a signal that predicted 50% reinforcement. Pigeons showed a strong preference for the Discriminative alternative that remained despite reducing the frequency of the signal for reinforcement in subsequent phases to 25% and then 12.5%. In Experiment 2, using the original design of Experiment 1, the stimulus following choice of the Nondiscriminative alternative was increased to 75% and then to 100%. Results showed that preference for the Discriminative alternative decreased only when the signals for reinforcement for the two alternatives predicted the same probability of reinforcement. The ability of several models to predict this behavior are discussed, but the terminal link stimulus value offers the most parsimonious account of this suboptimal behavior. PMID:27441394

  5. Making healthy choices easy choices: the role of empowerment.

    PubMed

    Koelen, M A; Lindström, B

    2005-08-01

    An important goal of health promotion is to make it easier for people to make healthy choices. However, this may be difficult if people do not feel control over their environment and their personal circumstances. An important concept in relation to this is empowerment. Health professionals are expected to facilitate and enable people moving towards empowerment. In this paper, we address the question what is meant by individual empowerment. In an attempt to provide a theoretical framework, we discuss individual empowerment from a salutogenic perspective. This perspective introduces two fundamental concepts: the general resistance resources, and the sense of coherence. In addition, in order to further clarify and operationalise the concept, some factors influencing individual empowerment are identified, that is, locus of control, learned helplessness, self-efficacy and outcome expectations. These concepts find common ground in feelings of (lack of) control, but they differ in stability and changeability. We provide some suggestions how these factors can be influenced, and we discuss the meaning of the identified factors for empowering interactions between professionals and their clients. Health professionals can facilitate people to see a correspondence between their efforts and the outcomes thereof, improve and facilitate health literacy, in a relationship which can be characterised as partnership.

  6. Nuclear position dictates DNA repair pathway choice

    PubMed Central

    Lemaître, Charlène; Grabarz, Anastazja; Tsouroula, Katerina; Andronov, Leonid; Furst, Audrey; Pankotai, Tibor; Heyer, Vincent; Rogier, Mélanie; Attwood, Kathleen M.; Kessler, Pascal; Dellaire, Graham; Klaholz, Bruno; Reina-San-Martin, Bernardo; Soutoglou, Evi

    2014-01-01

    Faithful DNA repair is essential to avoid chromosomal rearrangements and promote genome integrity. Nuclear organization has emerged as a key parameter in the formation of chromosomal translocations, yet little is known as to whether DNA repair can efficiently occur throughout the nucleus and whether it is affected by the location of the lesion. Here, we induce DNA double-strand breaks (DSBs) at different nuclear compartments and follow their fate. We demonstrate that DSBs induced at the nuclear membrane (but not at nuclear pores or nuclear interior) fail to rapidly activate the DNA damage response (DDR) and repair by homologous recombination (HR). Real-time and superresolution imaging reveal that DNA DSBs within lamina-associated domains do not migrate to more permissive environments for HR, like the nuclear pores or the nuclear interior, but instead are repaired in situ by alternative end-joining. Our results are consistent with a model in which nuclear position dictates the choice of DNA repair pathway, thus revealing a new level of regulation in DSB repair controlled by spatial organization of DNA within the nucleus. PMID:25366693

  7. Basic and applied research on choice responding.

    PubMed Central

    Fisher, W W; Mazur, J E

    1997-01-01

    Choice responding refers to the manner in which individuals allocate their time or responding among available response options. In this article, we first review basic investigations that have identified and examined variables that influence choice responding, such as response effort and reinforcement rate, immediacy, and quality. We then describe recent bridge and applied studies that illustrate how the results of basic research on choice responding can help to account for human behavior in natural environments and improve clinical assessments and interventions. PMID:9316255

  8. Parameter Estimation and Model Selection in Computational Biology

    PubMed Central

    Lillacci, Gabriele; Khammash, Mustafa

    2010-01-01

    A central challenge in computational modeling of biological systems is the determination of the model parameters. Typically, only a fraction of the parameters (such as kinetic rate constants) are experimentally measured, while the rest are often fitted. The fitting process is usually based on experimental time course measurements of observables, which are used to assign parameter values that minimize some measure of the error between these measurements and the corresponding model prediction. The measurements, which can come from immunoblotting assays, fluorescent markers, etc., tend to be very noisy and taken at a limited number of time points. In this work we present a new approach to the problem of parameter selection of biological models. We show how one can use a dynamic recursive estimator, known as extended Kalman filter, to arrive at estimates of the model parameters. The proposed method follows. First, we use a variation of the Kalman filter that is particularly well suited to biological applications to obtain a first guess for the unknown parameters. Secondly, we employ an a posteriori identifiability test to check the reliability of the estimates. Finally, we solve an optimization problem to refine the first guess in case it should not be accurate enough. The final estimates are guaranteed to be statistically consistent with the measurements. Furthermore, we show how the same tools can be used to discriminate among alternate models of the same biological process. We demonstrate these ideas by applying our methods to two examples, namely a model of the heat shock response in E. coli, and a model of a synthetic gene regulation system. The methods presented are quite general and may be applied to a wide class of biological systems where noisy measurements are used for parameter estimation or model selection. PMID:20221262

  9. Not all choices are created equal: Task-relevant choices enhance motor learning compared to task-irrelevant choices.

    PubMed

    Carter, Michael J; Ste-Marie, Diane M

    2017-02-21

    Lewthwaite et al. (2015) reported that the learning benefits of exercising choice (i.e., their self-controlled condition) are not restricted to task-relevant features (e.g., feedback). They found that choosing one's golf ball color (Exp. 1) or choosing which of two tasks to perform at a later time plus which of two artworks to hang (Exp. 2) resulted in better retention than did being denied these same choices (i.e., yoked condition). The researchers concluded that the learning benefits derived from choice, whether irrelevant or relevant to the to-be-learned task, are predominantly motivational because choice is intrinsically rewarding and satisfies basic psychological needs. However, the absence of a group that made task-relevant choices and the lack of psychological measures significantly weakened their conclusions. Here, we investigated how task-relevant and task-irrelevant choices affect motor-skill learning. Participants practiced a spatiotemporal motor task in either a task-relevant group (choice over feedback schedule), a task-irrelevant group (choice over the color of an arm-wrap plus game selection), or a no-choice group. The results showed significantly greater learning in the task-relevant group than in both the task-irrelevant and no-choice groups, who did not differ significantly. Critically, these learning differences were not attributed to differences in perceptions of competence or autonomy, but instead to superior error-estimation abilities. These results challenge the perspective that motivational influences are the root cause of self-controlled learning advantages. Instead, the findings add to the growing evidence highlighting that the informational value gained from task-relevant choices makes a greater relative contribution to these advantages than motivational influences do.

  10. Consumers, health insurance and dominated choices.

    PubMed

    Sinaiko, Anna D; Hirth, Richard A

    2011-03-01

    We analyze employee health plan choices when the choice set offered by their employer includes a dominated plan. During our study period, one-third of workers were enrolled in the dominated plan. Some may have selected the plan before it was dominated and then failed to switch out of it. However, a substantial number actively chose the dominated plan when they had an unambiguously better choice. These results suggest limitations in the ability of health reform based solely on consumer choice to achieve efficient outcomes and that implementation of health reform should anticipate, monitor and account for this consumer behavior.

  11. Teen Choice of Inwood House.

    PubMed

    1994-05-01

    The Teen Choice Program in New York City was described and the outcome of the program evaluation was reported. Teen Choice is a school based sex education and pregnancy prevention program run by trained social workers. The aim is to provide information, counseling, and referrals on a range of issues relating to sexuality. The program is elective and meets during a regularly scheduled gym period for one or two semesters from the 7th to the 12th grades. There are single sex and coeducational classes. The program aim is to change attitudes toward birth control, to change risky sexual behavior, such as unprotected coitus, to offer accurate knowledge about contraception, and to prevent unplanned pregnancies. Abstinence is encouraged, but for those sexually experienced, there is attention to responsible and reliable use of contraception. Program methods include small group discussion, individual counseling, and classroom discussion. Topics of discussion range from sexuality issues and birth control to values clarification and peer pressure. Small groups may discuss human sexual growth, relationship formation, family life, responsibility to self and others, consequences of teenage pregnancy, and social and cultural peer pressures. Girls are encouraged to assume more assertive and less reactive roles. Communication skills are reinforced in respectful exchanges of personal views and questions. Differentiating facts and issues is a primary focus. A question about when an individual first had sex would be redirected to asking about the appropriate age to first have sex. Respect for privacy helps to build students confidence in the program. A longitudinal evaluation conducted between 1984 and 1987 found that the program was effective in reaching and recruiting high risk adolescents. Students left the program with increased knowledge about contraception, more mature and responsible attitudes about the use of birth control, and reduced frequency of unprotected coitus. Boys were

  12. Enabling Predictive Simulation and UQ of Complex Multiphysics PDE Systems by the Development of Goal-Oriented Variational Sensitivity Analysis and a-Posteriori Error Estimation Methods

    SciTech Connect

    Estep, Donald

    2015-11-30

    This project addressed the challenge of predictive computational analysis of strongly coupled, highly nonlinear multiphysics systems characterized by multiple physical phenomena that span a large range of length- and time-scales. Specifically, the project was focused on computational estimation of numerical error and sensitivity analysis of computational solutions with respect to variations in parameters and data. In addition, the project investigated the use of accurate computational estimates to guide efficient adaptive discretization. The project developed, analyzed and evaluated new variational adjoint-based techniques for integration, model, and data error estimation/control and sensitivity analysis, in evolutionary multiphysics multiscale simulations.

  13. Male contraception: expanding reproductive choice.

    PubMed

    Rajalakshmi, M

    2005-11-01

    The development of steroid-based oral contraceptives had revolutionized the availability of contraceptive choice for women. In order to expand the contraceptive options for couples by developing an acceptable, safe and effective male contraceptive, scientists have been experimenting with various steroidal/non-steroidal regimens to suppress testicular sperm production. The non-availability of a long-acting androgen was a limiting factor in the development of a male contraceptive regimen since all currently tested anti-spermatogenic agents also concurrently decrease circulating testosterone levels. A combination regimen of long-acting progestogen and androgen would have advantage over an androgen-alone modality since the dose of androgen required would be much smaller in the combination regimen, thereby decreasing the adverse effects of high steroid load. The progestogen in the combination regimen would act as the primary anti-spermatogenic agent. Currently, a number of combination regimens using progestogen or GnRH analogues combined with androgen are undergoing trials. The side effects of long-term use of androgens and progestogens have also undergone evaluation in primate models and the results of these studies need to be kept in view, while considering steroidal regimens for contraceptive use in men. Efforts are also being made to popularize non-scalpel vasectomy and to develop condoms of greater acceptability. The development of contraceptive vaccines for men, using sperm surface epitopes not expressed in female reproductive tract as source, still requires considerable research efforts.

  14. Evaluating choices by single neurons in the frontal lobe: outcome value encoded across multiple decision variables.

    PubMed

    Kennerley, Steven W; Wallis, Jonathan D

    2009-05-01

    Damage to the frontal lobe can cause severe decision-making impairments. A mechanism that may underlie this is that neurons in the frontal cortex encode many variables that contribute to the valuation of a choice, such as its costs, benefits and probability of success. However, optimal decision-making requires that one considers these variables, not only when faced with the choice, but also when evaluating the outcome of the choice, in order to adapt future behaviour appropriately. To examine the role of the frontal cortex in encoding the value of different choice outcomes, we simultaneously recorded the activity of multiple single neurons in the anterior cingulate cortex (ACC), orbitofrontal cortex (OFC) and lateral prefrontal cortex (LPFC) while subjects evaluated the outcome of choices involving manipulations of probability, payoff and cost. Frontal neurons encoded many of the parameters that enabled the calculation of the value of these variables, including the onset and offset of reward and the amount of work performed, and often encoded the value of outcomes across multiple decision variables. In addition, many neurons encoded both the predicted outcome during the choice phase of the task as well as the experienced outcome in the outcome phase of the task. These patterns of selectivity were more prevalent in ACC relative to OFC and LPFC. These results support a role for the frontal cortex, principally ACC, in selecting between choice alternatives and evaluating the outcome of that selection thereby ensuring that choices are optimal and adaptive.

  15. Can "Word Choices" Compromise a Woman's Career?

    ERIC Educational Resources Information Center

    Mendoza, Sylvia

    2011-01-01

    A letter of recommendation can catapult a woman into the next phase of the interview process for a particular job--or land her in the slush pile. Word choice in describing this female candidate can make or break her career. Letters of recommendation--especially when a reference's word choice paints a negative, less than stellar picture of the…

  16. School Choice for Transnational Parents in Tokyo

    ERIC Educational Resources Information Center

    Velliaris, Donna M.; Willis, Craig R.

    2013-01-01

    School choice is centred on parents deciding where and how their children will be educated, and this issue is similar--to varying degrees--for parents all around the world. Parental school choice is the authority that parents exercise in making decisions about where their children will attend school, and choosing a particular educational pathway…

  17. A Teacher Examines School Choice Reform.

    ERIC Educational Resources Information Center

    Frick, William

    1994-01-01

    Examines the school choice movement in the United States, which advocates claim will make schools more efficient by allowing parents to select the best schools for their children. Argues that the school choice movement is a surreptitious plan to gradually put the functions of public education in private hands, with public funds going to support…

  18. Factors Influencing Career Choice among Police Recruits

    ERIC Educational Resources Information Center

    Cole, Bryan

    2012-01-01

    This quantitative, non-experimental study examined the career choice factors of 154 (n = 154) police recruits to determine a correlation of age group generation to the five career choice factors presented in the Sibson Reward of Work Model. Law enforcement agencies faced a shortage of viable candidates to fill vacant positions. While extensive…

  19. Choice and Diversity in Education: A Defence.

    ERIC Educational Resources Information Center

    Tooley, James

    1997-01-01

    Considers the criticism that recent reforms involving school choice and diversity do not adequately address issues of educational equity in Great Britain. Outlines a series of three reforms that could make the system more equitable given the assumption that school choice is desirable. Examines and criticizes these assumptions. (MJP)

  20. Using a Foreign Language Changes Our Choices.

    PubMed

    Hayakawa, Sayuri; Costa, Albert; Foucart, Alice; Keysar, Boaz

    2016-11-01

    A growing literature demonstrates that using a foreign language affects choice. This is surprising because if people understand their options, choice should be language independent. Here, we review the impact of using a foreign language on risk, inference, and morality, and discuss potential explanations, including reduced emotion, psychological distance, and increased deliberation.

  1. Responsibility and School Choice in Education

    ERIC Educational Resources Information Center

    Colburn, Ben

    2012-01-01

    Consider the following argument for school choice, based on an appeal to the virtues of the market: allowing parents some measure of choice over their particular children's education ultimately serves the interests of all children, because creating a market mechanism in state education will produce improvements through the same pressures that lead…

  2. A Chronology of Parental Choice in Education.

    ERIC Educational Resources Information Center

    McDonald, Sister Dale

    2001-01-01

    Traces the history of parental rights in education since the landmark case Pierce vs. the Society of Sisters (1925), when the existence of private schools was validated. States that initiatives promoting parental choice include : (1) tax relief/credits; (2) vouchers or scholarships; (3) public school choice; and (4) home schooling. Provides a…

  3. Constructive Multiple-Choice Testing System

    ERIC Educational Resources Information Center

    Park, Jooyong

    2010-01-01

    The newly developed computerized Constructive Multiple-choice Testing system is introduced. The system combines short answer (SA) and multiple-choice (MC) formats by asking examinees to respond to the same question twice, first in the SA format, and then in the MC format. This manipulation was employed to collect information about the two…

  4. Choices of local anesthetics for ocular surgery.

    PubMed

    Cass, Gary D

    2006-06-01

    This article will help clinicians to be aware of their choices of local anesthetic solutions before they make their ocular anesthetic plan based on the specific requirements of the patient, the surgical procedure, and the properties of the local anesthetic. Choices of local anesthetic solutions and additives for both topical anesthesia and conduction blockade are discussed.

  5. Consumer empowerment behavior and hospital choice.

    PubMed

    Weng, Hui-Ching

    2006-01-01

    The association between empowerment behavior and a patient's choice of hospitals was examined. Enhancing empowerment behavior did not lead to greater satisfaction with the choice made. The demographic profiles of three patient groups are presented and key health care marketing strategies are discussed.

  6. Career Choice Anxiety, Coping, and Perceived Control.

    ERIC Educational Resources Information Center

    Weinstein, Faye M.; Healy, Charles C.; Ender, Philip B.

    2002-01-01

    Presents a study exploring whether perceived control moderates the relation between coping with career indecision and choice anxiety among women in low-level jobs. Results revealed that perceived control interacted with problem-focused coping to increase accountable variance in choice anxiety. Discusses implications for interventions with women in…

  7. Career Choice and Development. Third Edition.

    ERIC Educational Resources Information Center

    Brown, Duane; And Others

    This book contains 12 papers examining established and newly emerging theories of career choice and development. Following prefaces to the third, second, and first editions by Duane Brown and Linda Brooks, the following papers are included: "Introduction to Theories of Career Development and Choice: Origins, Evolution, and Current Efforts" (Duane…

  8. Making the Most of Multiple Choice

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Multiple-choice questions draw criticism because many people perceive they test only recall or atomistic, surface-level objectives and do not require students to think. Although this can be the case, it does not have to be that way. Susan M. Brookhart suggests that multiple-choice questions are a useful part of any teacher's questioning repertoire…

  9. Work Values and College Major Choice

    ERIC Educational Resources Information Center

    Balsamo, Michela; Lauriola, Marco; Saggino, Aristide

    2013-01-01

    Our study sought to clarify the nature of the known individual differences in work values associated with academic college major choice, specifically the question whether these precede or follow the choice of an academic major. To rule out environmental influences during academic study, group differences in five value orientations were evaluated…

  10. Informed Consumer Choice in Community Rehabilitation Programs

    ERIC Educational Resources Information Center

    Hagen-Foley, Debra L.; Rosenthal, David A.; Thomas, Dale F.

    2005-01-01

    This study investigated consumer and staff member perceptions regarding the extent of consumer choice and participatory planning in community-based rehabilitation programs (CRPs) and the relationship between these elements, satisfaction, and outcomes. Consumers reported moderate to high levels of choice in services and employment goals, and…

  11. Household Mobility, School Choices, and School Outcomes.

    ERIC Educational Resources Information Center

    Bayer, Patrick J.

    This paper summarizes work from a dissertation, the main contribution of which was to develop and estimate a new empirical framework for analyzing the equilibrium outcomes of families' choices for choosing a particular residence. The principal component of the framework is a random-coefficients discrete-choice model of the residential location…

  12. Democratic Education and School Choice Revisited

    ERIC Educational Resources Information Center

    Paquette, Jerry

    2005-01-01

    This article features the author's reply to John Coons's "Dodging Democracy: The Educator's Flight from the Specter of Choice." First, he wants to thank Coons for his thoughtful and thought-provoking reply to "Public Funding for 'Private' Education: The Equity Challenge of Enhanced Choice." So thought provoking, in fact, did the author find…

  13. "Score Choice": A Tempest in a Teapot?

    ERIC Educational Resources Information Center

    Hoover, Eric

    2009-01-01

    A new option that allows students to choose which of their test scores to send to colleges has generated renewed criticism of the College Board. College Board officials tout the option, called Score Choice, as a way to ease test taker anxiety. Some prominent admissions officials have publicly described Score Choice as a sales tactic that will…

  14. Personality Differences in Career Choice Patterns

    ERIC Educational Resources Information Center

    Borges, Nicole J.; Roth, Karl S.; Seibel, Hugo R.

    2004-01-01

    Vocational identity is an important construct for physician career development. Physician vocational development has been grouped into three tasks (crystallization, specification, and implementation) pertaining to career choice and specialty choice (1) In defining the construct of vocational identity, it has been suggested that the relation…

  15. A Personalized Parents' Workshop on Vocational Choice

    ERIC Educational Resources Information Center

    Lea, H. Daniel

    1976-01-01

    A Parent's Workshop on Vocational Choice was conducted to stimulate thought and dialogue about career choice between secondary school students and their parents. Holland's Vocational Preference Inventory (VPI) was administered to students and their parents. Student responses were compared to their parents' predictions of their responses. A…

  16. 34 CFR 361.52 - Informed choice.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... informed choice, including the availability of support services for individuals with cognitive or other... acquiring information that enables them to exercise informed choice in the development of their IPEs with... vocational rehabilitation needs and during development of the IPE, the designated State unit must provide...

  17. 34 CFR 361.52 - Informed choice.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... informed choice, including the availability of support services for individuals with cognitive or other... acquiring information that enables them to exercise informed choice in the development of their IPEs with... vocational rehabilitation needs and during development of the IPE, the designated State unit must provide...

  18. 34 CFR 361.52 - Informed choice.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... informed choice, including the availability of support services for individuals with cognitive or other... acquiring information that enables them to exercise informed choice in the development of their IPEs with... vocational rehabilitation needs and during development of the IPE, the designated State unit must provide...

  19. 34 CFR 361.52 - Informed choice.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... informed choice, including the availability of support services for individuals with cognitive or other... acquiring information that enables them to exercise informed choice in the development of their IPEs with... vocational rehabilitation needs and during development of the IPE, the designated State unit must provide...

  20. 34 CFR 361.52 - Informed choice.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... informed choice, including the availability of support services for individuals with cognitive or other... acquiring information that enables them to exercise informed choice in the development of their IPEs with... vocational rehabilitation needs and during development of the IPE, the designated State unit must provide...

  1. Race, Social Background, and School Choice Options

    ERIC Educational Resources Information Center

    Goyette, Kimberly A.

    2008-01-01

    This research contributes to discussions about social inequality in school choices in two ways. First, educational choices include the multitude of options families may consider, including choosing a home in a particular area and home-schooling. Decision-making is considered not at a single point in time, but over children's educational careers.…

  2. Choice policies in Northern European health systems.

    PubMed

    Vrangbaek, Karsten; Robertson, Ruth; Winblad, Ulrika; Van de Bovenkamp, Hester; Dixon, Anna

    2012-01-01

    This paper compares the introduction of policies to promote or strengthen patient choice in four Northern European countries - Denmark, England, the Netherlands and Sweden. The paper examines whether there has been convergence in choice policies across Northern Europe. Following Christopher Pollitt's suggestion, the paper distinguishes between rhetorical (discursive) convergence, decision (design) convergence and implementation (operational) convergence (Pollitt, 2002). This leads to the following research question for the article: Is the introduction of policies to strengthen choice in the four countries characterised by discursive, decision and operational convergence? The paper concludes that there seems to be convergence among these four countries in the overall policy rhetoric about the objectives associated with patient choice, embracing both concepts of empowerment (the intrinsic value) and market competition (the instrumental value). It appears that the institutional context and policy concerns such as waiting times have been important in affecting the timing of the introduction of choice policies and implementation, but less so in the design of choice policies. An analysis of the impact of choice policies is beyond the scope of this paper, but it is concluded that further research should investigate how the institutional context and timing of implementation affect differences in how the choice policy works out in practice.

  3. Leadership Practices and School Choice. Research Brief

    ERIC Educational Resources Information Center

    Cravens, Xiu; Goldring, Ellen; Penaloza, Roberto V.

    2011-01-01

    As part of a larger study on school choice, researchers at the National Center on School Choice examined variation in leadership practices across school types, relying on a convenience matched sample of schools that included charter, magnet, private, and traditional public schools. A total of 284 schools agreed to participate in the study--116…

  4. Schools of Choice: An Annotated Catalog of Key Choice Elements: Open Enrollment, Diversity and Empowerment.

    ERIC Educational Resources Information Center

    Oakland Univ., Rochester, MI. School of Human and Educational Services.

    This catalog, an outcome of the Project To Access Choice in Education (PACE), lists examples of public schools throughout the nation offering choices in education. "Schools of Choice" are defined as those offering one or more of the following three dynamics: (1) open enrollment, the freedom for families to choose the elementary or secondary…

  5. Increasing Choice-Making and Choice Awareness for Students with Intellectual Disability

    ERIC Educational Resources Information Center

    Sparks, Shannon Lynn

    2013-01-01

    A number of studies have suggested that when children with disabilities are presented with choice-making opportunities, they can make choices (Bambara, 2004; Carlson, Luiselli, Slyman, & Markowski, 2008; Dibley & Lim, 1999; Manhertz, 2006). Teaching choice-making to students with intellectual disability is an important skill. Students with…

  6. S-SAD phasing of monoclinic histidine kinase from Brucella abortus combining data from multiple crystals and orientations: an example of data-collection strategy and a posteriori analysis of different data combinations.

    PubMed

    Klinke, Sebastián; Foos, Nicolas; Rinaldi, Jimena J; Paris, Gastón; Goldbaum, Fernando A; Legrand, Pierre; Guimarães, Beatriz G; Thompson, Andrew

    2015-07-01

    The histidine kinase (HK) domain belonging to the light-oxygen-voltage histidine kinase (LOV-HK) from Brucella abortus is a member of the HWE family, for which no structural information is available, and has low sequence identity (20%) to the closest HK present in the PDB. The `off-edge' S-SAD method in macromolecular X-ray crystallography was used to solve the structure of the HK domain from LOV-HK at low resolution from crystals in a low-symmetry space group (P21) and with four copies in the asymmetric unit (∼108 kDa). Data were collected both from multiple crystals (diffraction limit varying from 2.90 to 3.25 Å) and from multiple orientations of the same crystal, using the κ-geometry goniostat on SOLEIL beamline PROXIMA 1, to obtain `true redundancy'. Data from three different crystals were combined for structure determination. An optimized HK construct bearing a shorter cloning artifact yielded crystals that diffracted X-rays to 2.51 Å resolution and that were used for final refinement of the model. Moreover, a thorough a posteriori analysis using several different combinations of data sets allowed us to investigate the impact of the data-collection strategy on the success of the structure determination.

  7. Junior doctors' preferences for specialty choice.

    PubMed

    Sivey, Peter; Scott, Anthony; Witt, Julia; Joyce, Catherine; Humphreys, John

    2012-12-01

    A number of studies suggest that there is an over-supply of specialists and an under-supply of general practitioners in many developed countries. Previous econometric studies of specialty choice from the US suggest that although income plays a role, other non-pecuniary factors may be important. This paper presents a novel application of a choice experiment to identify the effects of expected future earnings and other attributes on specialty choice. We find the implied marginal wage estimated from our discrete choice model is close to the actual wages of senior specialists, but much higher than those of senior GPs. In a policy simulation we find that increasing GPs' earnings by $50,000, or increasing opportunities for procedural or academic work can increase the number of junior doctors choosing general practice by between 8 and 13 percentage points. The simulation implies an earnings elasticity of specialty choice of 0.95.

  8. Prenatal Screening, Reproductive Choice, and Public Health

    PubMed Central

    Wilkinson, Stephen

    2015-01-01

    One widely held view of prenatal screening (PNS) is that its foremost aim is, or should be, to enable reproductive choice; this is the Pure Choice view. The article critiques this position by comparing it with an alternative: Public Health Pluralism. It is argued that there are good reasons to prefer the latter, including the following. (1) Public Health Pluralism does not, as is often supposed, render PNS more vulnerable to eugenics-objections. (2) The Pure Choice view, if followed through to its logical conclusions, may have unpalatable implications, such as extending choice well beyond health screening. (3) Any sensible version of Public Health Pluralism will be capable of taking on board the moral seriousness of abortion and will advocate, where practicable, alternative means of reducing the prevalence of disease and disability. (4) Public Health Pluralism is at least as well-equipped as the Pure Choice model to deal with autonomy and consent issues. PMID:25521971

  9. Design parameters for wearable optical imagers

    NASA Astrophysics Data System (ADS)

    Akin, Ata; Kim, Sanghyun; Pourrezaei, Kambiz; Chance, Britton; Nioka, Shoko

    2001-06-01

    This paper summarizes the design steps that are followed during the development of the portable optical imager for breast cancer screening. The design steps considered the parameters such as total power consumption versus battery weight and size, speed of data acquisition versus cost and complexity of the design (functionality), graphical display versus operating system choice. We have used a single board computer system that uses Windows CE as the real time operating system. This choice was preferred since our graphical display requirements can only be carried out with the CE environment's GUI kernels.

  10. A fair range of choice: justifying maximum patient choice in the British National Health Service.

    PubMed

    Wilmot, Stephen

    2007-06-01

    In this paper I put forward an ethical argument for the provision of extensive patient choice by the British National Health Service. I base this argument on traditional liberal rights to freedom of choice, on a welfare right to health care, and on a view of health as values-based. I argue that choice, to be ethically sustainable on this basis, must be values-based and rational. I also consider whether the British taxpayer may be persuadable with regard to the moral acceptability of patient choice, making use of Rawls' theory of political liberalism in this context. I identify issues that present problems in terms of public acceptance of choice, and also identify a boundary issue with regard to public health choices as against individual choices.

  11. Choice of Variables and Preconditioning for Time Dependent Problems

    NASA Technical Reports Server (NTRS)

    Turkel, Eli; Vatsa, Verr N.

    2003-01-01

    We consider the use of low speed preconditioning for time dependent problems. These are solved using a dual time step approach. We consider the effect of this dual time step on the parameter of the low speed preconditioning. In addition, we compare the use of two sets of variables, conservation and primitive variables, to solve the system. We show the effect of these choices on both the convergence to a steady state and the accuracy of the numerical solutions for low Mach number steady state and time dependent flows.

  12. Propulsion System Choices and Their Implications

    NASA Technical Reports Server (NTRS)

    Joyner, Claude R., II; Levack, Daniel J. H.; Rhodes, Russell, E.; Robinson, John W.

    2010-01-01

    In defining a space vehicle architecture, the propulsion system and related subsystem choices will have a major influence on achieving the goals and objectives desired. There are many alternatives and the choices made must produce a system that meets the performance requirements, but at the same time also provide the greatest opportunity of reaching all of the required objectives. Recognizing the above, the SPST Functional Requirements subteam has drawn on the knowledge, expertise, and experience of its members, to develop insight that wiIJ effectively aid the architectural concept developer in making the appropriate choices consistent with the architecture goals. This data not only identifies many selected choices, but also, more importantly, presents the collective assessment of this subteam on the "pros" and the "cons" of these choices. The propulsion system choices with their pros and cons are presented in five major groups. A. System Integration Approach. Focused on the requirement for safety, reliability, dependability, maintainability, and low cost. B. Non-Chemical Propulsion. Focused on choice of propulsion type. C. Chemical Propulsion. Focused on propellant choice implications. D. Functional Integration. Focused on the degree of integration of the many propulsive and closely associated functions, and on the choice of the engine combustion power cycle. E. Thermal Management. Focused on propellant tank insulation and integration. Each of these groups is further broken down into subgroups, and at that level the consensus pros and cons are presented. The intended use of this paper is to provide a resource of focused material for architectural concept developers to use in designing new advanced systems including college design classes. It is also a possible source of input material for developing a model for designing and analyzing advanced concepts to help identify focused technology needs and their priorities.

  13. Estimation of Dynamic Discrete Choice Models by Maximum Likelihood and the Simulated Method of Moments

    PubMed Central

    Eisenhauer, Philipp; Heckman, James J.; Mosso, Stefano

    2015-01-01

    We compare the performance of maximum likelihood (ML) and simulated method of moments (SMM) estimation for dynamic discrete choice models. We construct and estimate a simplified dynamic structural model of education that captures some basic features of educational choices in the United States in the 1980s and early 1990s. We use estimates from our model to simulate a synthetic dataset and assess the ability of ML and SMM to recover the model parameters on this sample. We investigate the performance of alternative tuning parameters for SMM. PMID:26494926

  14. School Choice, School Quality and Postsecondary Attainment

    PubMed Central

    Deming, David J.; Hastings, Justine S.; Kane, Thomas J.; Staiger, Douglas O.

    2015-01-01

    We study the impact of a public school choice lottery in Charlotte-Mecklenburg schools on college enrollment and degree completion. We find a significant overall increase in college attainment among lottery winners who attend their first choice school. Using rich administrative data on peers, teachers, course offerings and other inputs, we show that the impacts of choice are strongly predicted by gains on several measures of school quality. Gains in attainment are concentrated among girls. Girls respond to attending a better school with higher grades and increases in college-preparatory course-taking, while boys do not. PMID:27244675

  15. Linear-Nonlinear-Poisson Models of Primate Choice Dynamics

    PubMed Central

    Corrado, Greg S; Sugrue, Leo P; Sebastian Seung, H; Newsome, William T

    2005-01-01

    The equilibrium phenomenon of matching behavior traditionally has been studied in stationary environments. Here we attempt to uncover the local mechanism of choice that gives rise to matching by studying behavior in a highly dynamic foraging environment. In our experiments, 2 rhesus monkeys (Macacca mulatta) foraged for juice rewards by making eye movements to one of two colored icons presented on a computer monitor, each rewarded on dynamic variable-interval schedules. Using a generalization of Wiener kernel analysis, we recover a compact mechanistic description of the impact of past reward on future choice in the form of a Linear-Nonlinear-Poisson model. We validate this model through rigorous predictive and generative testing. Compared to our earlier work with this same data set, this model proves to be a better description of choice behavior and is more tightly correlated with putative neural value signals. Refinements over previous models include hyperbolic (as opposed to exponential) temporal discounting of past rewards, and differential (as opposed to fractional) comparisons of option value. Through numerical simulation we find that within this class of strategies, the model parameters employed by animals are very close to those that maximize reward harvesting efficiency. PMID:16596981

  16. Stochastic Matching and the Voluntary Nature of Choice

    PubMed Central

    Neuringer, Allen; Jensen, Greg; Piff, Paul

    2007-01-01

    Attempts to characterize voluntary behavior have been ongoing for thousands of years. We provide experimental evidence that judgments of volition are based upon distributions of responses in relation to obtained rewards. Participants watched as responses, said to be made by “actors,” appeared on a computer screen. The participant's task was to estimate how well each actor represented the voluntary choices emitted by a real person. In actuality, all actors' responses were generated by algorithms based on Baum's (1979) generalized matching function. We systematically varied the exponent values (sensitivity parameter) of these algorithms: some actors matched response proportions to received reinforcer proportions, others overmatched (predominantly chose the highest-valued alternative), and yet others undermatched (chose relatively equally among the alternatives). In each of five experiments, we found that the matching actor's responses were judged most closely to approximate voluntary choice. We found also that judgments of high volition depended upon stochastic (or probabilistic) generation. Thus, stochastic responses that match reinforcer proportions best represent voluntary human choice. PMID:17725049

  17. Is your choice my choice? The owners' effect on pet dogs' (Canis lupus familiaris) performance in a food choice task.

    PubMed

    Prato-Previde, E; Marshall-Pescini, S; Valsecchi, P

    2008-01-01

    This study investigates the influence of owners on their dogs' performance in a food choice task using either different or equal quantities of food. Fifty-four pet dogs were tested in three different conditions. In Condition 1 we evaluated their ability to choose between a large and small amount of food (quantity discrimination task). In Condition 2 dogs were again presented with a choice between the large and small food quantity, but only after having witnessed their owner favouring the small quantity. In Condition 3 dogs were given a choice between two equally small quantities of food having witnessed their owner favouring either one or the other. A strong effect of the owner on the dogs' performance was observed. In Condition 1 dogs as a group chose significantly more often the large food quantity, thus showing their ability to solve the quantity discrimination task. After observing their owner expressing a preference for the small food quantity they chose the large quantity of food significantly less than in the independent choice situation. The tendency to conform to the owner's choice was higher when the dogs had to choose between equally small quantities of food (Condition 3) rather than between a large and a small one (Condition 2). These results provide evidence that dogs can be influenced by their owners even when their indications are clearly in contrast with direct perceptual information, thus leading dogs to ultimately make counterproductive choices.

  18. Monkeys are more patient in a foraging task than in a standard intertemporal choice task.

    PubMed

    Blanchard, Tommy C; Hayden, Benjamin Y

    2015-01-01

    Studies of animal impulsivity generally find steep subjective devaluation, or discounting, of delayed rewards - often on the order of a 50% reduction in value in a few seconds. Because such steep discounting is highly disfavored in evolutionary models of time preference, we hypothesize that discounting tasks provide a poor measure of animals' true time preferences. One prediction of this hypothesis is that estimates of time preferences based on these tasks will lack external validity, i.e. fail to predict time preferences in other contexts. We examined choices made by four rhesus monkeys in a computerized patch-leaving foraging task interleaved with a standard intertemporal choice task. Monkeys were significantly more patient in the foraging task than in the intertemporal choice task. Patch-leaving behavior was well fit by parameter-free optimal foraging equations but poorly fit by the hyperbolic discount parameter obtained from the intertemporal choice task. Day-to-day variation in time preferences across the two tasks was uncorrelated with each other. These data are consistent with the conjecture that seemingly impulsive behavior in animals is an artifact of their difficulty understanding the structure of intertemporal choice tasks, and support the idea that animals are more efficient rate maximizers in the multi-second range than intertemporal choice tasks would suggest.

  19. Refusing The Choice: Balancing Life and Work

    NASA Astrophysics Data System (ADS)

    Brooks, J.

    2012-12-01

    The Choice The intellect of man is forced to choose perfection of the life, or of the work, And if it take the second must refuse A heavenly mansion, raging in the dark. When all that story's finished, what's the news? In luck or out the toil has left its mark: That old perplexity an empty purse, Or the day's vanity, the night's remorse. William Butler Yeats William Yeats put forward The Choice that I feel too many scientists feel they must make. Too often, many choose to leave science. How do we refuse this choice and find balance between life and our careers? While I don't know the answer, I will share choices that have lead to not perfection but satisfaction in science careers and lives. The role of mentors, supportive spouses, the luck of the job, and flexibility in research directions have all contributed to being able to refuse to choose.

  20. Strategy application, observability, and the choice combinator.

    SciTech Connect

    Winter, Victor Lono

    2004-03-01

    In many strategic systems, the choice combinator provides a powerful mechanism for controlling the application of rules and strategies to terms. The ability of the choice combinator to exercise control over rewriting is based on the premise that the success and failure of strategy application can be observed. In this paper we present a higher-order strategic framework with the ability to dynamically construct strategies containing the choice combinator. To this framework, a combinator called hide is introduced that prevents the successful application of a strategy from being observed by the choice combinator. We then explore the impact of this new combinator on a real-world problem involving a restricted implementation of the Java Virtual Machine.

  1. Irrational choice and the value of information

    PubMed Central

    Vasconcelos, Marco; Monteiro, Tiago; Kacelnik, Alex

    2015-01-01

    Irrational decision making in humans and other species challenges the use of optimality in behavioural biology. Here we show that such observations are in fact powerful tools to understand the adaptive significance of behavioural mechanisms. We presented starlings choices between probabilistic alternatives, receiving or not information about forthcoming, delayed outcomes after their choices. Subjects could not use this information to alter the outcomes. Paradoxically, outcome information induced loss-causing preference for the lower probability option. The effect depended on time under uncertainty: information given just after each choice caused strong preference for lower probability, but information just before the outcome did not. A foraging analysis shows that these preferences would maximize gains if post-choice information were usable, as when predators abandon a chase when sure of the prey escaping. Our study illustrates how experimentally induced irrational behaviour supports rather than weakens the evolutionary optimality approach to animal behaviour. PMID:26350951

  2. Whose Choice? Teaching Films About Abortion

    ERIC Educational Resources Information Center

    Gledhill, Christine

    1977-01-01

    Examines a film entitled "Whose Choice?" which chronicles the struggle to protect and extend existing abortion rights through the campaigns set in motion by the James White Abortion (Amendment) Bill (1975). (MH)

  3. Irrational choice and the value of information.

    PubMed

    Vasconcelos, Marco; Monteiro, Tiago; Kacelnik, Alex

    2015-09-09

    Irrational decision making in humans and other species challenges the use of optimality in behavioural biology. Here we show that such observations are in fact powerful tools to understand the adaptive significance of behavioural mechanisms. We presented starlings choices between probabilistic alternatives, receiving or not information about forthcoming, delayed outcomes after their choices. Subjects could not use this information to alter the outcomes. Paradoxically, outcome information induced loss-causing preference for the lower probability option. The effect depended on time under uncertainty: information given just after each choice caused strong preference for lower probability, but information just before the outcome did not. A foraging analysis shows that these preferences would maximize gains if post-choice information were usable, as when predators abandon a chase when sure of the prey escaping. Our study illustrates how experimentally induced irrational behaviour supports rather than weakens the evolutionary optimality approach to animal behaviour.

  4. Making Choices about Everyday Care (for Families)

    MedlinePlus

    ... here Home Making Choices About Everyday Care (for Families) Order this publication Printer-friendly version The diagnosis ... 30 Smart Patients Caregivers Community In partnership with Family Caregiver Alliance Learn more CAREGIVER STORIES I feel ...

  5. Multi-choice stochastic bi-level programming problem in cooperative nature via fuzzy programming approach

    NASA Astrophysics Data System (ADS)

    Maiti, Sumit Kumar; Roy, Sankar Kumar

    2016-05-01

    In this paper, a Multi-Choice Stochastic Bi-Level Programming Problem (MCSBLPP) is considered where all the parameters of constraints are followed by normal distribution. The cost coefficients of the objective functions are multi-choice types. At first, all the probabilistic constraints are transformed into deterministic constraints using stochastic programming approach. Further, a general transformation technique with the help of binary variables is used to transform the multi-choice type cost coefficients of the objective functions of Decision Makers(DMs). Then the transformed problem is considered as a deterministic multi-choice bi-level programming problem. Finally, a numerical example is presented to illustrate the usefulness of the paper.

  6. Enhancing Consumer Choice: Are We Making Appropriate Recommendations?

    ERIC Educational Resources Information Center

    Lee, Jinkook; Geistfeld, Loren V.

    1998-01-01

    This study used conjoint analysis to identify consumer choice models. Results suggest a need to base choice-making aids on ideal choice models if the aid is to lead consumers to decisions consistent with true preferences. (Author/JOW)

  7. Powder Flow Testing: Judicious Choice of Test Methods.

    PubMed

    Tay, Justin Yong Soon; Liew, Celine Valeria; Heng, Paul Wan Sia

    2016-11-14

    Flow property of pharmaceutical powders can be assessed by various flow testers and test methods. In this study, eight commercially available lactose grades were sourced and tested for angles of repose, tapping studies, shear cell measurements, stirred powder rheometry, and avalanching powder measurements. The relationships between various flow parameters and particle size were analyzed. Deviations from the general trend could be attributed to either the insensitivity of the test or differences in particle shape. The basic flowability energy of the powder rheometer was unable to reconcile the effects of shape and particle size on powder flowability. Avalanche time of the revolving drum powder analyzer and angle of repose exhibited good correlation with each other (r = 0.92) but experienced poor resolution for samples of smaller particle sizes due to powder cohesiveness and the propensity for agglomerative flow. Flow test parameters could be categorized into three broad types, based on their relationship with particle size: (i) linear relationship, (ii) test parameter more sensitive to smaller sized particles, and (iii) test parameter more sensitive to larger sized particles. Choice of test parameters used to represent powder flow should be dependent on the sensitivity of the selected flow test methods to the sample types.

  8. A Normalized Direct Approach for Estimating the Parameters of the Normal Ogive Three-Parameter Model for Ability Tests.

    ERIC Educational Resources Information Center

    Gugel, John F.

    A new method for estimating the parameters of the normal ogive three-parameter model for multiple-choice test items--the normalized direct (NDIR) procedure--is examined. The procedure is compared to a more commonly used estimation procedure, Lord's LOGIST, using computer simulations. The NDIR procedure uses the normalized (mid-percentile)…

  9. Dynamics in the Parameter Space of a Neuron Model

    NASA Astrophysics Data System (ADS)

    Paulo, C. Rech

    2012-06-01

    Some two-dimensional parameter-space diagrams are numerically obtained by considering the largest Lyapunov exponent for a four-dimensional thirteen-parameter Hindmarsh—Rose neuron model. Several different parameter planes are considered, and it is shown that depending on the combination of parameters, a typical scenario can be preserved: for some choice of two parameters, the parameter plane presents a comb-shaped chaotic region embedded in a large periodic region. It is also shown that there exist regions close to these comb-shaped chaotic regions, separated by the comb teeth, organizing themselves in period-adding bifurcation cascades.

  10. Search, Memory, and Choice Error: An Experiment.

    PubMed

    Sanjurjo, Adam

    2015-01-01

    Multiple attribute search is a central feature of economic life: we consider much more than price when purchasing a home, and more than wage when choosing a job. An experiment is conducted in order to explore the effects of cognitive limitations on choice in these rich settings, in accordance with the predictions of a new model of search memory load. In each task, subjects are made to search the same information in one of two orders, which differ in predicted memory load. Despite standard models of choice treating such variations in order of acquisition as irrelevant, lower predicted memory load search orders are found to lead to substantially fewer choice errors. An implication of the result for search behavior, more generally, is that in order to reduce memory load (thus choice error) a limited memory searcher ought to deviate from the search path of an unlimited memory searcher in predictable ways-a mechanism that can explain the systematic deviations from optimal sequential search that have recently been discovered in peoples' behavior. Further, as cognitive load is induced endogenously (within the task), and found to affect choice behavior, this result contributes to the cognitive load literature (in which load is induced exogenously), as well as the cognitive ability literature (in which cognitive ability is measured in a separate task). In addition, while the information overload literature has focused on the detrimental effects of the quantity of information on choice, this result suggests that, holding quantity constant, the order that information is observed in is an essential determinant of choice failure.

  11. Search, Memory, and Choice Error: An Experiment

    PubMed Central

    Sanjurjo, Adam

    2015-01-01

    Multiple attribute search is a central feature of economic life: we consider much more than price when purchasing a home, and more than wage when choosing a job. An experiment is conducted in order to explore the effects of cognitive limitations on choice in these rich settings, in accordance with the predictions of a new model of search memory load. In each task, subjects are made to search the same information in one of two orders, which differ in predicted memory load. Despite standard models of choice treating such variations in order of acquisition as irrelevant, lower predicted memory load search orders are found to lead to substantially fewer choice errors. An implication of the result for search behavior, more generally, is that in order to reduce memory load (thus choice error) a limited memory searcher ought to deviate from the search path of an unlimited memory searcher in predictable ways-a mechanism that can explain the systematic deviations from optimal sequential search that have recently been discovered in peoples' behavior. Further, as cognitive load is induced endogenously (within the task), and found to affect choice behavior, this result contributes to the cognitive load literature (in which load is induced exogenously), as well as the cognitive ability literature (in which cognitive ability is measured in a separate task). In addition, while the information overload literature has focused on the detrimental effects of the quantity of information on choice, this result suggests that, holding quantity constant, the order that information is observed in is an essential determinant of choice failure. PMID:26121356

  12. Partner Choice in Raven (Corvus corax) Cooperation

    PubMed Central

    Asakawa-Haas, Kenji; Schiestl, Martina; Bugnyar, Thomas; Massen, Jorg J. M.

    2016-01-01

    Although social animals frequently make decisions about when or with whom to cooperate, little is known about the underlying mechanisms of partner choice. Most previous studies compared different dyads’ performances, though did not allow an actual choice among partners. We tested eleven ravens, Corvus corax, in triads, giving them first the choice to cooperate with either a highly familiar or a rather unfamiliar partner and, second, with either a friend or a non-friend using a cooperative string-pulling task. In either test, the ravens had a second choice and could cooperate with the other partner, given that this one had not pulled the string in the meantime. We show that during the experiments, these partner ravens indeed learn to wait and inhibit pulling, respectively. Moreover, the results of these two experiments show that ravens’ preferences for a specific cooperation partner are not based on familiarity. In contrast, the ravens did show a preference based on relationship quality, as they did choose to cooperate significantly more with friends than with non-friends and they were also more proficient when cooperating with a friend. In order to further identify the proximate mechanism of this preference, we designed an open-choice experiment for the whole group where all birds were free to cooperate on two separate apparatuses. This set-up allowed us to distinguish between preferences for close proximity and preferences to cooperate. The results revealed that friends preferred staying close to each other, but did not necessarily cooperate with one another, suggesting that tolerance of proximity and not relationship quality as a whole may be the driving force behind partner choice in raven cooperation. Consequently, we stress the importance of experiments that allow such titrations and, suggest that these results have important implications for the interpretations of cooperation studies that did not include open partner choice. PMID:27286247

  13. CHAMP: Changepoint Detection Using Approximate Model Parameters

    DTIC Science & Technology

    2014-06-01

    detecting changes in the parameters and mod- els that generate observed data. Commonly cited examples include detecting changes in stock market behavior [4...experimentally verified using artifi- cially generated data and are compared to those of Fearnhead and Liu [5]. 2 Related work Hidden Markov Models ( HMMs ) are...largely the de facto tool of choice when analyzing time series data, but the standard HMM formulation has several undesirable properties. The number of

  14. Choice-Induced Preference Change in the Free-Choice Paradigm: A Critical Methodological Review

    PubMed Central

    Izuma, Keise; Murayama, Kou

    2013-01-01

    Choices not only reflect our preference, but they also affect our behavior. The phenomenon of choice-induced preference change has been of interest to cognitive dissonance researchers in social psychology, and more recently, it has attracted the attention of researchers in economics and neuroscience. Preference modulation after the mere act of making a choice has been repeatedly demonstrated over the last 50 years by an experimental paradigm called the “free-choice paradigm.” However, Chen and Risen (2010) pointed out a serious methodological flaw in this paradigm, arguing that evidence for choice-induced preference change is still insufficient. Despite the flaw, studies using the traditional free-choice paradigm continue to be published without addressing the criticism. Here, aiming to draw more attention to this issue, we briefly explain the methodological problem, and then describe simple simulation studies that illustrate how the free-choice paradigm produces a systematic pattern of preference change consistent with cognitive dissonance, even without any change in true preference. Our stimulation also shows how a different level of noise in each phase of the free-choice paradigm independently contributes to the magnitude of artificial preference change. Furthermore, we review ways of addressing the critique and provide a meta-analysis to show the effect size of choice-induced preference change after addressing the critique. Finally, we review and discuss, based on the results of the stimulation studies, how the criticism affects our interpretation of past findings generated from the free-choice paradigm. We conclude that the use of the conventional free-choice paradigm should be avoided in future research and the validity of past findings from studies using this paradigm should be empirically re-established. PMID:23404185

  15. Referential Choice: Predictability and Its Limits

    PubMed Central

    Kibrik, Andrej A.; Khudyakova, Mariya V.; Dobrov, Grigory B.; Linnik, Anastasia; Zalmanov, Dmitrij A.

    2016-01-01

    We report a study of referential choice in discourse production, understood as the choice between various types of referential devices, such as pronouns and full noun phrases. Our goal is to predict referential choice, and to explore to what extent such prediction is possible. Our approach to referential choice includes a cognitively informed theoretical component, corpus analysis, machine learning methods and experimentation with human participants. Machine learning algorithms make use of 25 factors, including referent’s properties (such as animacy and protagonism), the distance between a referential expression and its antecedent, the antecedent’s syntactic role, and so on. Having found the predictions of our algorithm to coincide with the original almost 90% of the time, we hypothesized that fully accurate prediction is not possible because, in many situations, more than one referential option is available. This hypothesis was supported by an experimental study, in which participants answered questions about either the original text in the corpus, or about a text modified in accordance with the algorithm’s prediction. Proportions of correct answers to these questions, as well as participants’ rating of the questions’ difficulty, suggested that divergences between the algorithm’s prediction and the original referential device in the corpus occur overwhelmingly in situations where the referential choice is not categorical. PMID:27721800

  16. Parental role models, gender and educational choice.

    PubMed

    Dryler, H

    1998-09-01

    Parental role models are often put forward as an explanation for the choice of gender-atypical educational routes. This paper aims to test such explanations by examining the impact of family background variables like parental education and occupation, on choice of educational programme at upper secondary school. Using a sample of around 73,000 Swedish teenagers born between 1972 and 1976, girls' and boys' gender-atypical as well as gender-typical educational choices are analysed by means of logistic regression. Parents working or educated within a specific field increase the probability that a child will make a similar choice of educational programme at upper secondary school. This same-sector effect appeared to be somewhat stronger for fathers and sons, while no such same-sex influence was confirmed for girls. No evidence was found that, in addition to a same-sector effect, it matters whether parents' occupations represent gender-traditional or non-traditional models. Parents of the service classes or highly educated parents--expected to be the most gender egalitarian in attitudes and behaviours--have a positive influence upon children's choice of gender-atypical education.

  17. The drift diffusion model as the choice rule in reinforcement learning.

    PubMed

    Pedersen, Mads Lund; Frank, Michael J; Biele, Guido

    2016-12-13

    Current reinforcement-learning models often assume simplified decision processes that do not fully reflect the dynamic complexities of choice processes. Conversely, sequential-sampling models of decision making account for both choice accuracy and response time, but assume that decisions are based on static decision values. To combine these two computational models of decision making and learning, we implemented reinforcement-learning models in which the drift diffusion model describes the choice process, thereby capturing both within- and across-trial dynamics. To exemplify the utility of this approach, we quantitatively fit data from a common reinforcement-learning paradigm using hierarchical Bayesian parameter estimation, and compared model variants to determine whether they could capture the effects of stimulant medication in adult patients with attention-deficit hyperactivity disorder (ADHD). The model with the best relative fit provided a good description of the learning process, choices, and response times. A parameter recovery experiment showed that the hierarchical Bayesian modeling approach enabled accurate estimation of the model parameters. The model approach described here, using simultaneous estimation of reinforcement-learning and drift diffusion model parameters, shows promise for revealing new insights into the cognitive and neural mechanisms of learning and decision making, as well as the alteration of such processes in clinical groups.

  18. A Thurstonian Pairwise Choice Model with Univariate and Multivariate Spline Transformations.

    ERIC Educational Resources Information Center

    De Soete, Geert; Winsberg, Suzanne

    1993-01-01

    A probabilistic choice model, based on L. L. Thurstone's Law of Comparative Judgment Case V, is developed for paired comparisons data about psychological stimuli. The model assumes that each stimulus is measured on a small number of physical variables. An algorithm for estimating parameters is illustrated with real data. (SLD)

  19. The "Tyranny of Choice": Choice Overload as a Possible Instance of Effort Discounting

    ERIC Educational Resources Information Center

    Reed, Derek D.; Reed, Florence D. DiGennaro; Chok, James; Brozyna, Gary A.

    2011-01-01

    When making a choice, people like to have options, but an emerging literature on "choice overload" suggests that the provision of too many options results in adverse experiences, including a depletion of cognitive resources and postdecision feelings of regret. A strong implication is that individuals should shy away from situations…

  20. Final Report of Project CHOICE: A Center for Helping Organizations Improve Choice in Education.

    ERIC Educational Resources Information Center

    Chapman, Davis W.; And Others

    The purpose of the Center for Helping Organizations Improve Choice in Education (CHOICE) project, the scope of its activities, and evaluations of the effectiveness of those activities are described. One major project goal was to encourage and facilitate institutional efforts to provide more complete and accurate information to prospective…

  1. Preferences, Information, and Parental Choice Behavior in Public School Choice. NBER Working Paper No. 12995

    ERIC Educational Resources Information Center

    Hastings, Justine S.; Van Weelden, Richard; Weinstein, Jeffrey

    2007-01-01

    The incentives and outcomes generated by public school choice depend to a large degree on parents' choice behavior. There is growing empirical evidence that low-income parents place lower weights on academics when choosing schools, but there is little evidence as to why. We use a field experiment in the Charlotte-Mecklenburg Public School district…

  2. AdChoices? Compliance with Online Behavioral Advertising Notice and Choice Requirements. Revised Version

    DTIC Science & Technology

    2011-10-07

    Alliance Announces Self-Regulatory Program For Online Behavioural Advertising, http://www.dglaw.com/images_user/newsalerts/AdvMktngPromo_Behavioral...including AOL Advertising, Collective, Google, interCLICK, and Traffic Marketplace. This suggests that some online advertising buyers are interested in...AdChoices? Compliance with Online Behavioral Advertising Notice and Choice Requirements Saranga Komanduri, Richard Shay, Greg

  3. Similar Performance, but Different Choices: Social Class and Higher Education Choice in Greece

    ERIC Educational Resources Information Center

    Sianou-Kyrgiou, Eleni; Tsiplakides, Iakovos

    2011-01-01

    Higher education choice has been a central theme in sociological research in recent decades, especially following the policies for the widening of participation adopted in many countries. Research has shown a relationship between social class and higher education choice, and this is a reason why the expansion of higher education does not reduce…

  4. Refocusing College Choice: Women's Reflections on Their Postsecondary Education Choices

    ERIC Educational Resources Information Center

    Bergerson, Amy A.; Heiselt, April K.; Aiken-Wisniewski, Sharon

    2013-01-01

    College choice is often tied to persistence and it emphasizes how family background affects both enrollment in higher education and persistence to degree. Despite extensive research related to both access to higher education and choice processes, there is still much to be learned about students' postsecondary decisions. This qualitative study…

  5. Transition Choices Program: Preparing To Participate in Life's Choices. Teaching Guide and Curriculum.

    ERIC Educational Resources Information Center

    Stowitschek, Joseph J.; And Others

    The Transition Choices Program (TCP) is designed to increase the ability of young persons with disabilities to participate more fully in the school-to-adult life process through systematic instruction in six skills: exploring choices and developing preferences; planning goals and following through; seeking assistance when needed; recognizing and…

  6. School Choice, Competition, and Academic Quality: Essays on the Milwaukee Parental Choice Program

    ERIC Educational Resources Information Center

    Mader, Nicholas Salomon

    2010-01-01

    The essays of this dissertation contribute to the understanding of how public schools respond to competition in educational markets. Evidence is drawn from the Milwaukee Parental Choice Program, the longest-running and largest-scale private school voucher program in the United States. A major justification school choice programs is that they…

  7. Efficient and Flexible Strategy Use on Multi-Digit Sums: A Choice/No-Choice Study

    ERIC Educational Resources Information Center

    Torbeyns, Joke; Verschaffel, Lieven

    2013-01-01

    This study analysed children's use of mental computation strategies and standard written algorithms in the domain of multi-digit addition and subtraction, using the choice/no-choice method. Twenty-one Flemish fourth-graders (M[subscript Age] =9y10m) solved problem-items that either stimulated the use of mental computation strategies or a standard…

  8. The Relationship between Career Choice Attitudes and Career Choice Competencies of Ninth-Grade Pupils

    ERIC Educational Resources Information Center

    Westbrook, Bert W.

    1976-01-01

    This paper presents the results of a study designed to determine whether or not Career Choice Attitudes and Career Choice Competencies are interrelated as hypothesized in the Crites' (1965, 1973a) model of career maturity. Resulting correlations appear to be mostly consistent with the model of career maturity. (Author)

  9. Determinants of Awareness, Consideration, and Choice Set Size in University Choice.

    ERIC Educational Resources Information Center

    Dawes, Philip L.; Brown, Jennifer

    2002-01-01

    Developed and tested a model of students' university "brand" choice using five individual-level variables (ethnic group, age, gender, number of parents going to university, and academic ability) and one situational variable (duration of search) to explain variation in the sizes of awareness, consideration, and choice decision sets. (EV)

  10. Every School a School of Choice: School Choice in Ireland as Viewed through American Eyes

    ERIC Educational Resources Information Center

    Buchanan, Nina K.; Fox, Robert A.

    2008-01-01

    "Choice" and "freedom" as measured by the ability of parents to select their children's schools are deeply embedded in the national ethos of the United States of America. Wealthy American parents have always exercised school choice but minority and low-income students are often trapped in failing schools. This paper is based on…

  11. Will Choice Hurt? Compared to What? A School Choice Experiment in Estonia

    ERIC Educational Resources Information Center

    Põder, Kaire; Lauri, Triin

    2014-01-01

    This article presents the empirical analysis of the effects of a school choice policy in Estonia. The article shows that relying on markets and giving autonomy to the schools over student selection will produce admission tests, even at the elementary school level. This article's contribution is to show that a school choice policy experiment with…

  12. Visual mate choice in poison frogs.

    PubMed Central

    Summers, K; Symula, R; Clough, M; Cronin, T

    1999-01-01

    We investigated female mate choice on the basis of visual cues in two populations of Dendrobates pumilio, the strawberry poison frog, from the Bocas del Toro Archipelago in Panama, Central America. Mate choice experiments were carried out by presenting subject females of each of two morphs of this species (orange and green) from two different island populations (Nancy Key and Pope Island) with object frogs (one of each morph) under glass at one end of a terrarium. Recorded calls were played simultaneously from behind both object frogs. The experiments were carried out under two light regimes: (i) white light, and (ii) relatively monochromatic filtered blue light. Subject females from each population displayed a significant preference for their own morph under white light, but not under blue light. These results indicate that female D. pumilio use visual cues in mate choice, and suggest that colour may be the visual cue they use. PMID:10649631

  13. Does reflection lead to wise choices?

    PubMed Central

    Bortolotti, Lisa

    2011-01-01

    Does conscious reflection lead to good decision-making? Whereas engaging in reflection is traditionally thought to be the best way to make wise choices, recent psychological evidence undermines the role of reflection in lay and expert judgement. The literature suggests that thinking about reasons does not improve the choices people make, and that experts do not engage in reflection, but base their judgements on intuition, often shaped by extensive previous experience. Can we square the traditional accounts of wisdom with the results of these empirical studies? Should we even attempt to? I shall defend the view that philosophy and cognitive sciences genuinely interact in tackling questions such as whether reflection leads to making wise choices. PMID:22408385

  14. When good news leads to bad choices.

    PubMed

    McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L; Ludvig, Elliot A

    2016-01-01

    Pigeons and other animals sometimes deviate from optimal choice behavior when given informative signals for delayed outcomes. For example, when pigeons are given a choice between an alternative that always leads to food after a delay and an alternative that leads to food only half of the time after a delay, preference changes dramatically depending on whether the stimuli during the delays are correlated with (signal) the outcomes or not. With signaled outcomes, pigeons show a much greater preference for the suboptimal alternative than with unsignaled outcomes. Key variables and research findings related to this phenomenon are reviewed, including the effects of durations of the choice and delay periods, probability of reinforcement, and gaps in the signal. We interpret the available evidence as reflecting a preference induced by signals for good news in a context of uncertainty. Other explanations are briefly summarized and compared.

  15. APS control system operating system choice

    SciTech Connect

    Knott, M.; Kraimer, M.; Lenkszus, F.

    1990-05-01

    The purpose of this document is to set down the reasons and decisions regarding what is an important choice for the APS Control System design staff, namely the choice of an operating system for its principle computer resources. Since the choice also may affect cost estimates and the design handbook, there is a further need to document the process. The descriptions and explanations which follow are intended for reading by other APS technical area managers and will contain a minimum of buzz-words, and where buzz-words are used, they will be explained. The author hopes that it will help in understanding the current trends and developments in the volatile and fast-developing computer field.

  16. Nonrestricted multiple-choice examination items.

    PubMed

    Kolstad, R; Goaz, P; Kolstad, R

    1982-08-01

    Multiple-choice items are frequently used in objective examinations. The format chosen should conform to the nature of the instruction. Knowledge about cumulative information, such as lists of attributes, can be tested efficiently by means of multiple-choice items that include a variable number of correct answers. In contrast to conventional, single-answer questions, nonrestricted multiple-choice items are capable of including more facts and fewer incorrect responses. In addition, the nonrestricted format is not burdened with the repetitious pattern of one correct answer coupled with several incorrect responses, a cue that may promote successful guessing. Item analyses can be performed on examinations that include both conventional and nonrestricted items. The reliability of one examination constructed totally with nonrestricted items was analyzed by means of the Kuder-Richardson Formula No. 20. The value 0.72 proved this examination to be both discriminating and consistent.

  17. Does Presentation Order Impact Choice After Delay?

    PubMed

    Berger, Jonah

    2016-07-01

    Options are often presented incidentally in a sequence, but does serial position impact choice after delay, and if so, how? We address this question in a consequential real-world choice domain. Using 25 years of citation data, and a unique identification strategy, we examine the relationship between article order (i.e., position in a journal issue) and citation count. Results indicate that mere serial position affects the prominence that research achieves: Earlier-listed articles receive more citations. Furthermore, our identification strategy allows us to cast doubt on alternative explanations (i.e., editorial placement) and instead indicate that the effect is driven by psychological processes of attention and memory. These findings deepen the understanding of how presentation order impacts choice, suggest that subtle presentation factors can bias an important scientific metric, and shed light on how psychological processes shape collective outcomes.

  18. GALAPAGOS: from pixels to parameters

    NASA Astrophysics Data System (ADS)

    Barden, Marco; Häußler, Boris; Peng, Chien Y.; McIntosh, Daniel H.; Guo, Yicheng

    2012-05-01

    To automate source detection, two-dimensional light profile Sérsic modelling and catalogue compilation in large survey applications, we introduce a new code Galaxy Analysis over Large Areas: Parameter Assessment by GALFITting Objects from SEXTRACTOR (GALAPAGOS). Based on a single set-up, GALAPAGOS can process a complete set of survey images. It detects sources in the data, estimates a local sky background, cuts postage stamp images for all sources, prepares object masks, performs Sérsic fitting including neighbours and compiles all objects in a final output catalogue. For the initial source detection, GALAPAGOS applies SEXTRACTOR, while GALFIT is incorporated for modelling Sérsic profiles. It measures the background sky involved in the Sérsic fitting by means of a flux growth curve. GALAPAGOS determines postage stamp sizes based on SEXTRACTOR shape parameters. In order to obtain precise model parameters, GALAPAGOS incorporates a complex sorting mechanism and makes use of modern CPU's multiplexing capabilities. It combines SEXTRACTOR and GALFIT data in a single output table. When incorporating information from overlapping tiles, GALAPAGOS automatically removes multiple entries from identical sources. GALAPAGOS is programmed in the Interactive Data Language (IDL). We test the stability and the ability to properly recover structural parameters extensively with artificial image simulations. Moreover, we apply GALAPAGOS successfully to the STAGES data set. For one-orbit Hubble Space Telescope data, a single 2.2-GHz CPU processes about 1000 primary sources per 24 h. Note that GALAPAGOS results depend critically on the user-defined parameter set-up. This paper provides useful guidelines to help the user make sensible choices.

  19. Does Expert Advice Improve Educational Choice?

    PubMed Central

    2015-01-01

    This paper reports evidence that an individual meeting with a study counselor at high school significantly improves the quality of choice of tertiary educational field, as self-assessed 18 months after graduation from college. To address endogeneity, we explore the variation in study counseling practices between schools as an instrumental variable (IV). Following careful scrutiny of the validity of the IV, our results indicate a significant and positive influence of study counseling on the quality of educational choice, foremost among males and those with low educated parents. The overall result is stable across a number of robustness checks. PMID:26692388

  20. Host nutritive quality and host plant choice in two grass miners: primary roles for primary compounds?

    PubMed

    Scheirs, Jan; De Bruyn, Luc; Verhagen, Ron

    2003-06-01

    The relationship between host plant choice and plant nutritional quality was investigated in two oligophagous grass miners Chromatomyia milii and C. nigra (Diptera, Agromyzidae). We tested whether host choice is determined by chemically mediated host suitability for offspring performance and/or adult performance. A second goal was to relate the observed variation among the different fitness parameters to quantitative and qualitative variation in foliar food quality. Choice experiments illustrated that both miners discriminated among grass species, and that C. milii has a smaller host range than C. nigra, as observed under natural conditions. Oviposition preference was correlated with adult feeding preference and related adult performance (longevity and fecundity) for both miners. Offspring performance measures (survival and pupal size) of at least C. nigra were more weakly related to host preference. Nearly all variation in adult performance of both miners was explained by foliar protein content, which had a positive effect on adult longevity and fecundity. Pupal size of both miners was positively related to foliar water and amino acid content and negatively related to lignin content. No clear relationship between host chemistry and offspring survival was observed. These observations show that fitness parameters are differentially related to host chemistry. Secondly, they suggest that chemically mediated host suitability for adult performance is an important determinant of host choice in this species. Finally, the results suggest a primary role for foliar protein content in host choice of the study species in general and in shaping the host range of C. milii in particular.

  1. School Choice in America: The Great Debate. Hot Topics Series.

    ERIC Educational Resources Information Center

    Metcalf, Kim K., Ed.; Muller, Patricia A., Ed.; Legan, Natalie A., Ed.

    This document strives to answer questions about school choice, such as What does school choice mean?, What does school choice look like?, and What are the likely consequences of giving parents greater voice in their children's education? Reports are grouped into three thematic chapters. In chapter 1, "Public-Public Choice," reports include:…

  2. School Choice and Segregation: "Tracking" Racial Equity in Magnet Schools

    ERIC Educational Resources Information Center

    Davis, Tomeka M.

    2014-01-01

    Three arguments regarding racial equity have arisen in the school choice debate. Choice advocates charge that choice will improve access to quality schools for disadvantaged minority students (Chubb & Moe 1990; Coons & Sugarman, 1978; Godwin & Kemerer, 2002; Viteritti, 1999). Critics argue that choice is unlikely to benefit minority…

  3. The ABCs of School Choice, 2009-2010 Edition

    ERIC Educational Resources Information Center

    Friedman Foundation for Educational Choice, 2010

    2010-01-01

    This publication presents the 2009-2010 edition of the Friedman Foundation for Educational Choice's "ABCs of School Choice". The "ABCs of School Choice" provides the latest in up-to-date and accurate information about the many school choice success stories taking place throughout the country. Readers will find this guide an…

  4. School Choice in a Post-Desegregation World

    ERIC Educational Resources Information Center

    Cobb, Casey D.; Glass, Gene V.

    2009-01-01

    In contrast to unregulated school choice, regulated choice programs oversee the assignment of students to schools with equity in mind. This article puts forth evidence for three claims with respect to unregulated and regulated school choice: (c) Unregulated choice plans tend to exacerbate the stratification of students along race, class, and…

  5. Thermodynamic consistency of the interaction parameter formalism

    NASA Astrophysics Data System (ADS)

    Srikanth, S.; Jacob, K. T.

    1988-04-01

    The apparent contradiction between the exact nature of the interaction parameter formalism as presented by Lupis and Elliott and the inconsistencies discussed recently by Pelton and Bale arise from the truncation of the Maclaurin series in the latter treatment. The truncation removes the exactness of the expression for the logarithm of the activity coefficient of a solute in a multi-component system. The integrals are therefore path dependent. Formulae for integration along paths of constant Xi, or X i/Xj are presented. The expression for In γsolvent given by Pelton and Bale is valid only in the limit that the mole fraction of solvent tends to one. The truncation also destroys the general relations between interaction parameters derived by Lupis and Elliott. For each specific choice of parameters special relationships are obtained between interaction parameters.

  6. Enhanced nearfield acoustic holography for larger distances of reconstructions using fixed parameter Tikhonov regularization

    DOE PAGES

    Chelliah, Kanthasamy; Raman, Ganesh G.; Muehleisen, Ralph T.

    2016-07-07

    This paper evaluates the performance of various regularization parameter choice methods applied to different approaches of nearfield acoustic holography when a very nearfield measurement is not possible. For a fixed grid resolution, the larger the hologram distance, the larger the error in the naive nearfield acoustic holography reconstructions. These errors can be smoothed out by using an appropriate order of regularization. In conclusion, this study shows that by using a fixed/manual choice of regularization parameter, instead of automated parameter choice methods, reasonably accurate reconstructions can be obtained even when the hologram distance is 16 times larger than the grid resolution.

  7. Estimating A Reference Standard Segmentation With Spatially Varying Performance Parameters: Local MAP STAPLE

    PubMed Central

    Commowick, Olivier; Akhondi-Asl, Alireza; Warfield, Simon K.

    2012-01-01

    We present a new algorithm, called local MAP STAPLE, to estimate from a set of multi-label segmentations both a reference standard segmentation and spatially varying performance parameters. It is based on a sliding window technique to estimate the segmentation and the segmentation performance parameters for each input segmentation. In order to allow for optimal fusion from the small amount of data in each local region, and to account for the possibility of labels not being observed in a local region of some (or all) input segmentations, we introduce prior probabilities for the local performance parameters through a new Maximum A Posteriori formulation of STAPLE. Further, we propose an expression to compute confidence intervals in the estimated local performance parameters. We carried out several experiments with local MAP STAPLE to characterize its performance and value for local segmentation evaluation. First, with simulated segmentations with known reference standard segmentation and spatially varying performance, we show that local MAP STAPLE performs better than both STAPLE and majority voting. Then we present evaluations with data sets from clinical applications. These experiments demonstrate that spatial adaptivity in segmentation performance is an important property to capture. We compared the local MAP STAPLE segmentations to STAPLE, and to previously published fusion techniques and demonstrate the superiority of local MAP STAPLE over other state-of-the- art algorithms. PMID:22562727

  8. Choice in the repeated-gambles experiment.

    PubMed

    Silberberg, A; Murray, P; Christensen, J; Asano, T

    1988-09-01

    Humans chose 10 times between two roulette wheels projected on a monitor. During the first trial, the left wheel provided a hypothetical $100 with p = .94, and the right wheel provided $250 with p = .39. A titration procedure adjusted the probability of a $250 win across trials to permit estimation of an indifference point between alternatives. In Experiment 1, intertrial-interval duration (25 vs. 90 s) and whether sessions began with an intertrial interval or a trial were varied in a 2 x 2 design in this risky-choice procedure. Risk aversion (preference for the $100 wheel) increased with intertrial interval but was unaffected by whether sessions began with a trial or an intertrial interval. In Experiment 2, all sessions began with a trial, and subjects were informed that the experiment ended after 10 trials. Intertrial-interval duration had no effect on choice. In Experiment 3, intertrial-interval duration and whether subjects were given $10 or $10,000 before beginning were varied among four groups in a 2 x 2 design. In all other ways, the procedure was unchanged from Experiment 2. Intertrial interval had no effect on choice, but the $10,000 groups showed less risk aversion than the $10 groups. These results can be explained more readily in terms of Kahneman and Tversky's (1984) notion of "framing of the prospect" than in terms of Rachlin, Logue, Gibbon, and Frankel's (1986) behavioral account of risky choice.

  9. Moral Choices in Contemporary Society: Source Book.

    ERIC Educational Resources Information Center

    Hellman, Mary, Ed.

    One of several supplementary materials for a newspaper course on moral choices in contemporary society, this sourcebook contains program ideas and resources to help civic leaders and educators plan programs based on the course topics. There are four sections. The first section explains how the topics can be used in planning programs, identifies…

  10. Children's Choices: Teaching with Books Children Like.

    ERIC Educational Resources Information Center

    Roser, Nancy, Ed.; Frith, Margaret, Ed.

    Supplementing Children's Choices--a list of children's literature that children grades K-8 found most enjoyable, published annually in "The Reading Teacher" journal--this collection of articles provides suggestions for effective use of children's favorite books in the classroom. In addition to providing an extensive bibliography of…

  11. The response dynamics of preferential choice.

    PubMed

    Koop, Gregory J; Johnson, Joseph G

    2013-12-01

    The ubiquity of psychological process models requires an increased degree of sophistication in the methods and metrics that we use to evaluate them. We contribute to this venture by capitalizing on recent work in cognitive science analyzing response dynamics, which shows that the bearing information processing dynamics have on intended action is also revealed in the motor system. This decidedly "embodied" view suggests that researchers are missing out on potential dependent variables with which to evaluate their models-those associated with the motor response that produces a choice. The current work develops a method for collecting and analyzing such data in the domain of decision making. We first validate this method using widely normed stimuli from the International Affective Picture System (Experiment 1), and demonstrate that curvature in response trajectories provides a metric of the competition between choice options. We next extend the method to risky decision making (Experiment 2) and develop predictions for three popular classes of process model. The data provided by response dynamics demonstrate that choices contrary to the maxim of risk seeking in losses and risk aversion in gains may be the product of at least one "online" preference reversal, and can thus begin to discriminate amongst the candidate models. Finally, we incorporate attentional data collected via eye-tracking (Experiment 3) to develop a formal computational model of joint information sampling and preference accumulation. In sum, we validate response dynamics for use in preferential choice tasks and demonstrate the unique conclusions afforded by response dynamics over and above traditional methods.

  12. Incentives, Choice, Education and Well-Being

    ERIC Educational Resources Information Center

    Schwartz, Barry

    2009-01-01

    It is a truism that giving people multiple reasons to engage in some activity will increase the chances of that activity--that two reasons are better than one. It is another truism, in the developed, Western world, that more freedom brings more well-being, and that more choice brings more freedom. In education, these truisms have led to the use of…

  13. Investigating intertemporal choice through experimental evolutionary robotics.

    PubMed

    Paglieri, Fabio; Parisi, Domenico; Patacchiola, Massimiliano; Petrosino, Giancarlo

    2015-06-01

    In intertemporal choices, subjects face a trade-off between value and delay: achieving the most valuable outcome requires a longer time, whereas the immediately available option is objectively poorer. Intertemporal choices are ubiquitous, and comparative studies reveal commonalities and differences across species: all species devalue future rewards as a function of delay (delay aversion), yet there is a lot of inter-specific variance in how rapidly such devaluation occurs. These differences are often interpreted in terms of ecological rationality, as depending on environmental factors (e.g., feeding ecology) and the physiological and morphological constraints of different species (e.g., metabolic rate). Evolutionary hypotheses, however, are hard to verify in vivo, since it is difficult to observe precisely enough real environments, not to mention ancestral ones. In this paper, we discuss the viability of an approach based on evolutionary robotics: in Study 1, we evolve robots without a metabolism in five different ecologies; in Study 2, we evolve metabolic robots (i.e., robots that consume energy over time) in three different ecologies. The intertemporal choices of the robots are analyzed both in their ecology and under laboratory conditions. Results confirm the generality of delay aversion and the usefulness of studying intertemporal choice through experimental evolutionary robotics.

  14. Matching, Demand, Maximization, and Consumer Choice

    ERIC Educational Resources Information Center

    Wells, Victoria K.; Foxall, Gordon R.

    2013-01-01

    The use of behavioral economics and behavioral psychology in consumer choice has been limited. The current study extends the study of consumer behavior analysis, a synthesis between behavioral psychology, economics, and marketing, to a larger data set. This article presents the current work and results from the early analysis of the data. We…

  15. Modeling Spanish Mood Choice in Belief Statements

    ERIC Educational Resources Information Center

    Robinson, Jason R.

    2013-01-01

    This work develops a computational methodology new to linguistics that empirically evaluates competing linguistic theories on Spanish verbal mood choice through the use of computational techniques to learn mood and other hidden linguistic features from Spanish belief statements found in corpora. The machine learned probabilistic linguistic models…

  16. Weighing Huck Finn's Choices and Decisions.

    ERIC Educational Resources Information Center

    Demastes, William

    1988-01-01

    Presents five steps to understanding and assessing Huckleberry Finn's decision-making process: (1) determining options; (2) describing the "system" of thinking that justifies one option over another; (3) observing which option is chosen; (4) determining how that supporting "system" rationalizes choice; and (5) assessing whether…

  17. Choice, Conditioned Reinforcement, and the Prius Effect

    ERIC Educational Resources Information Center

    Fantino, Edmund

    2008-01-01

    Psychologists have long been intrigued with the rationales that underlie our decisions. Similarly, the concept of conditioned reinforcement has a venerable history, particularly in accounting for behavior not obviously maintained by primary reinforcers. The studies of choice and of conditioned reinforcement have often developed in lockstep. Many…

  18. Language Choice on soc.culture.punjab.

    ERIC Educational Resources Information Center

    Paolillo, John C.

    1996-01-01

    Examines factors influencing language choice on the newsgroup soc.culture.punjab, a forum discussing the culture of the Punjab region of India and Pakistan. Finds that Punjabi is used only with interlocutors who are Punjabi community members. Accounts for limited usage in terms of intergenerational language shift, cultural ambivalence among…

  19. Women and the Choice to Study Economics

    ERIC Educational Resources Information Center

    Emerson, Tisha L. N.; McGoldrick, KimMarie; Mumford, Kevin J.

    2012-01-01

    Underrepresentation of women in economics is documented in many studies. Investigation of its sources at the undergraduate level is examined through students' decisions to persist in economics, either beyond an introductory course or in their major choices. The authors add to the literature by analyzing students' decisions to take their first…

  20. Does Challenge by Choice Increase Participation?

    ERIC Educational Resources Information Center

    Chase, Daniel L.

    2015-01-01

    Challenge by choice (CBC) has been regarded as a foundational principle for challenge ropes course programs. Although CBC is widely accepted as the primary mechanism for facilitating intended ropes course outcomes, especially a participant's involvement, until recently it had remained an untested assumption. This study explored the role of CBC as…

  1. MLS Students' Choice of a Library Career.

    ERIC Educational Resources Information Center

    Van House, Nancy A.

    1988-01-01

    A survey of library school students examined: (1) preferences influencing career choice; (2) reasons for getting an MLS; (3) comparisons with alternative occupations; (4) accuracy of expectations about salaries and placement; (5) comparison of expectations of students with and without previous library experience; and (6) differences between male…

  2. Code Choice in the Language Classroom

    ERIC Educational Resources Information Center

    Levine, Glenn S.

    2011-01-01

    Code Choice in the Language Classroom argues that the foreign language classroom is and should be regarded as a multilingual community of practice rather than as a perpetually deficient imitator of an exclusive second-language environment. From a sociocultural and ecological perspective, Levine guides the reader through a theoretical, empirical,…

  3. Career Path Guide for Adult Career Choices.

    ERIC Educational Resources Information Center

    Case, Clydia

    Intended for adults who are considering career choices or changes, this booklet provides opportunities for self-study and reflection in six career paths. The booklet begins with tips for long-term career survival and myths and realities of career planning. After a brief career survey, readers are introduced to six career paths: arts and…

  4. Misrepresenting "Choice Biographies"?: A Reply to Woodman

    ERIC Educational Resources Information Center

    Roberts, Steven

    2010-01-01

    This paper provides a reply to Woodman's (2009) recent argument that youth studies often incorrectly attribute the concept of "choice biographies" to the work of Ulrich Beck. Drawing heavily on Beck's own words, this paper contends that youth researchers might not be making this association unduly. Consideration is paid to some conceptual issues…

  5. Elementary Magnet School Students' Interracial Interaction Choices.

    ERIC Educational Resources Information Center

    Dickinson, Gerald B.; Holifield, Mitchell L.; Holifield, Glenda; Creer, Donna Grady

    2000-01-01

    Investigated elementary students' interracial interaction preferences in four desegregated, urban magnet schools. Data from a sociogram of students' working, playing, and sitting choices indicated that black students were less willing than white students to interact. Racial considerations were more pronounced among girls. There was no trend toward…

  6. 45 CFR 98.30 - Parental choice.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Welfare Department of Health and Human Services GENERAL ADMINISTRATION CHILD CARE AND DEVELOPMENT FUND Program Operations (Child Care Services)-Parental Rights and Responsibilities § 98.30 Parental choice. (a) The parent or parents of an eligible child who receives or is offered child care services shall...

  7. 45 CFR 98.30 - Parental choice.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CHILD CARE AND DEVELOPMENT FUND Program Operations (Child Care Services)-Parental Rights and Responsibilities § 98.30 Parental choice. (a) The parent or parents of an eligible child who receives or is offered child care services shall...

  8. 45 CFR 98.30 - Parental choice.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CHILD CARE AND DEVELOPMENT FUND Program Operations (Child Care Services)-Parental Rights and Responsibilities § 98.30 Parental choice. (a) The parent or parents of an eligible child who receives or is offered child care services shall...

  9. 45 CFR 98.30 - Parental choice.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CHILD CARE AND DEVELOPMENT FUND Program Operations (Child Care Services)-Parental Rights and Responsibilities § 98.30 Parental choice. (a) The parent or parents of an eligible child who receives or is offered child care services shall...

  10. 45 CFR 98.30 - Parental choice.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CHILD CARE AND DEVELOPMENT FUND Program Operations (Child Care Services)-Parental Rights and Responsibilities § 98.30 Parental choice. (a) The parent or parents of an eligible child who receives or is offered child care services shall...

  11. School Choice Tradeoffs: Liberty, Equity and Diversity.

    ERIC Educational Resources Information Center

    Godwin, R. Kenneth; Kemerer, Frank R.

    Education policy should encourage liberty and equality of opportunity, political tolerance, respect for diversity, and citizenship. The authors compare current policy that uses family residence to assign students to schools with alternative policies that range from expanding public choice options to school vouchers. They identify the benefits and…

  12. Choice Shift in Opinion Network Dynamics

    NASA Astrophysics Data System (ADS)

    Gabbay, Michael

    Choice shift is a phenomenon associated with small group dynamics whereby group discussion causes group members to shift their opinions in a more extreme direction so that the mean post-discussion opinion exceeds the mean pre-discussion opinion. Also known as group polarization, choice shift is a robust experimental phenomenon and has been well-studied within social psychology. In opinion network models, shifts toward extremism are typically produced by the presence of stubborn agents at the extremes of the opinion axis, whose opinions are much more resistant to change than moderate agents. However, we present a model in which choice shift can arise without the assumption of stubborn agents; the model evolves member opinions and uncertainties using coupled nonlinear differential equations. In addition, we briefly describe the results of a recent experiment conducted involving online group discussion concerning the outcome of National Football League games are described. The model predictions concerning the effects of network structure, disagreement level, and team choice (favorite or underdog) are in accord with the experimental results. This research was funded by the Office of Naval Research and the Defense Threat Reduction Agency.

  13. Choices and Motivations of Infertile Couples.

    ERIC Educational Resources Information Center

    van Balen, Frank; Verdurmen, Jacqueline; Ketting, Evert

    1997-01-01

    Infertile couples' (N=131) consideration of options for dealing with infertility (medical help, adoption, fostering, alternative medicine, and focusing on other life goals) is studied. Options were related to specific motivations including altruistic motives for adoption or foster care. Results, timing of choices, and motivations are discussed.…

  14. School Choice Evidence and Its Significance

    ERIC Educational Resources Information Center

    Merrifield, John

    2008-01-01

    Pressing questions about the merits of full-fledged market accountability in K-12 education, and more limited choice programs, have spawned a large scholarly literature. This article assesses what we know from the most prominent studies and the importance of those findings to school system reform discussions. The studies most widely cited in the…

  15. Neural Correlates of Affective Influence on Choice

    ERIC Educational Resources Information Center

    Piech, Richard M.; Lewis, Jade; Parkinson, Caroline H.; Owen, Adrian M.; Roberts, Angela C.; Downing, Paul E.; Parkinson, John A.

    2010-01-01

    Making the right choice depends crucially on the accurate valuation of the available options in the light of current needs and goals of an individual. Thus, the valuation of identical options can vary considerably with motivational context. The present study investigated the neural structures underlying context dependent evaluation. We instructed…

  16. Mate Choice: Charting Desire's Tangled Bank.

    PubMed

    Rosenthal, Gil G

    2016-04-04

    Choosing a mate requires a way to turn sexual arousal into sexual action. A recent paper identifies a hormone receptor that acts as a molecular gatekeeper in reproductive decisions. Focusing on mate-choice mechanisms may clarify longstanding evolutionary puzzles in sexual selection and speciation.

  17. Restricted Liberty, Parental Choice and Homeschooling

    ERIC Educational Resources Information Center

    Merry, Michael S.; Karsten, Sjoerd

    2010-01-01

    In this paper the authors carefully study the problem of liberty as it applies to school choice, and whether there ought to be restricted liberty in the case of homeschooling. They examine three prominent concerns that might be brought against homeschooling, viz., that it aggravates social inequality, worsens societal conflict and works against…

  18. Project Choice: Lessons Learned in Dropout Prevention.

    ERIC Educational Resources Information Center

    Sims, Abby

    In Project Choice, Ewing Marion Kauffman, through his Kauffman Foundation, offered a college education to inner city youth in selected schools in Kansas City, Kansas, and Kansas City, Missouri. In exchange students and parents agreed among other things that students would avoid disciplinary problems in school and the community, maintain…

  19. School Choice Litigation after "Zelman" and "Locke"

    ERIC Educational Resources Information Center

    Liekweg, John A.

    2004-01-01

    In the past 2 years, the United States Supreme Court has decided two important cases that will bear directly on legislation and litigation involving school choice programs that provide financial aid to parents of children attending religious schools. Those cases are "Zelman v. Simmons-Harris" (2002) and "Locke v. Davey" (2004).…

  20. Program to Combat Stereotyping in Career Choice.

    ERIC Educational Resources Information Center

    Harrison, Laurie R.

    Divided into three sections which deal with sex, race, and handicap stereotyping in career choice, the twenty-eight programs described here attempt to combat stereotypes among students and/or staff (K-12). Most descriptions list the goals of the program, target population, staffing and management, facilities and activities, program effectiveness…

  1. Personality Factors and Occupational Specialty Choice.

    ERIC Educational Resources Information Center

    Borges, Nicole J.; Jones, Bonnie J.

    This study is a continuation of an earlier investigation of personality and medical specialty choice. The earlier study determined that personality differences existed among family practitioners, anesthesiologists, and general surgeons. Based on this initial research, an attempt was made to answer the question of how the personality factors of…

  2. The Probabilistic Nature of Preferential Choice

    ERIC Educational Resources Information Center

    Rieskamp, Jorg

    2008-01-01

    Previous research has developed a variety of theories explaining when and why people's decisions under risk deviate from the standard economic view of expected utility maximization. These theories are limited in their predictive accuracy in that they do not explain the probabilistic nature of preferential choice, that is, why an individual makes…

  3. Public School Choice: A Selected Annotated Bibliography.

    ERIC Educational Resources Information Center

    Crohn, Leslie; Hansen, Kenneth H.

    This annotated bibliography offers a sampling of a wide variety of viewpoints on the topic of school choice. Fourteen references selected for annotation, ranging from a 3-page journal article to a 266-page book, are listed at the beginning of the bibliography. Among the viewpoints that different authors represent are the following: (1) unlimited…

  4. Choice, Charters, and Public School Competition

    ERIC Educational Resources Information Center

    Hanushek, Eric A.

    2006-01-01

    In the last century, public schools changed in ways that dramatically reduced the control that parents have over their local schools. Regaining that control is one key to improving the quality of our schools, and giving students a choice of schools is one way of increasing the influence that parents have over the way schools are run. Several…

  5. Choice: A Thematic Sequence of English Units.

    ERIC Educational Resources Information Center

    Institute for Services to Education, Inc., Washington, DC.

    One of a series of volumes containing units on specific themes designed for use in college freshman English courses, this particular volume considers the issue of choice through literature (short stories, novels, and poems). A section describing chamber theatre technique, which is an integral part of many of the units in this sequence, is…

  6. Race, Inequality of Opportunity, and School Choice

    ERIC Educational Resources Information Center

    Darby, Derrick; Saatcioglu, Argun

    2015-01-01

    Both neoliberals and liberals call for mitigating inequality of educational opportunity stemming from circumstances beyond an individual's control. In this article, we challenge the wisdom of making equality of opportunity hinge on emphasizing the distinction rather than the relationship between choices and circumstances. We utilize an empirical…

  7. Gender and Choice in Education and Occupation.

    ERIC Educational Resources Information Center

    Radford, John, Ed.

    Nine chapters present cutting-edge research on "brainsex" and its effects on personality, education, and choice. It targets concepts such as job attributes, work flexibility, long-term life planning, home-work conflict, prestige versus occupational interest, and intrinsic motivational mechanisms to explain the relative failure of…

  8. Methodological Choices in Rating Speech Samples

    ERIC Educational Resources Information Center

    O'Brien, Mary Grantham

    2016-01-01

    Much pronunciation research critically relies upon listeners' judgments of speech samples, but researchers have rarely examined the impact of methodological choices. In the current study, 30 German native listeners and 42 German L2 learners (L1 English) rated speech samples produced by English-German L2 learners along three continua: accentedness,…

  9. Doing School Choice Right: Preliminary Findings

    ERIC Educational Resources Information Center

    Harvey, James; Hill, Paul T.

    2006-01-01

    The Center on Reinventing Public Education (CRPE) has launched a new initiative entitled "Doing School Choice Right." Funded by the Bill and Melinda Gates, Annie E. Casey, and Lynde and Harry Bradley Foundations, the initiative's goal is to help state and local leaders handle practical issues whose resolution can determine whether school…

  10. Science, Technology and the Matter of Choice

    ERIC Educational Resources Information Center

    Tellez, Theresa

    1973-01-01

    Discusses the problem faced by underdeveloped countries of making the right choices about the application of science and technology. The main issues facing Latin American countries center on how much research they should undertake, how much technology they should innovate and adopt, and how much they should continue to import. (Author/JR)

  11. Teaching, Communication, and Book Choice Processes

    ERIC Educational Resources Information Center

    Ryan, Dana Marie

    2013-01-01

    Allowing students to select their own books for independent reading has been linked to increased reading engagement, heightened motivation to read, and greater independence and efficacy in reading. However, there has been little exploration of the processes surrounding book choice in elementary classrooms, particularly teaching practices that…

  12. Typeface and Multiple Choice Option Format.

    ERIC Educational Resources Information Center

    Follman, John; And Others

    The effects of typeface and item options arrangement on comprehension as indicated by multiple-choice test performance were investigated. Copies of the Ability to Interpret Reading Materials in the Social Studies, SRA Iowa Tests of Educational Development, Form X-4 were prepared in four typefaces: elite, pica, proportional, and script. For each…

  13. Career Choices Among Saudi Medical Students.

    ERIC Educational Resources Information Center

    Al-Faris, Eiad; And Others

    1997-01-01

    A survey of 253 final-year students at the four Saudi medical schools found the most frequently-chosen specialties were internal medicine, surgery, pediatrics, and obstetrics/gynecology. Over one-fourth were unsure of career choice. Gender differences were found. Most common locations for postgraduate training were Saudi Arabia and Canada, and a…

  14. Queer Decisions? Gay Male Students' University Choices

    ERIC Educational Resources Information Center

    Taulke-Johnson, Richard

    2010-01-01

    This article examines the reported influences on the university choices of 17 gay male undergraduate students attending a UK institution. It is argued that this process is strongly mediated by, and, therefore, has to be considered in relation to, class. Data analysis provides insight into the factors gay students say are important in selecting…

  15. More Choices, Higher Scores, and Worse Education

    ERIC Educational Resources Information Center

    American Educator, 2010

    2010-01-01

    If there is one thing all educators know and many studies have confirmed for decades, it is that there is no single answer to educational improvement. There are no grounds for the claim made in the past decade that accountability all by itself is a silver bullet, nor for the oft-asserted argument that choice by itself is a panacea. This article…

  16. Turning to Teaching: Gender and Career Choice

    ERIC Educational Resources Information Center

    Raggl, Andrea; Troman, Geoff

    2008-01-01

    As the largest public sector institution in the United Kingdom, education is a key site for studying the context of "choice" and changes in the identities of professional workers in contemporary society. Recruitment and retention problems in education have led to the creation of new routes into teaching to attract career changers from…

  17. From School Choice to Student Voice.

    ERIC Educational Resources Information Center

    Heckman, Paul E.; Montera, Viki L.

    2001-01-01

    Educational mass marketing approaches are like fast-food franchises; they offer homogeneous, standardized products that cannot satisfy every consumer's needs. A niche market looks inside the masses to address more individual, specialized choices missing from the menu. Variability, not uniformity, should guide development of public schooling. (MLH)

  18. Handbook of Research on School Choice

    ERIC Educational Resources Information Center

    Berends, Mark, Ed.; Springer, Matthew G., Ed.; Ballou, Dale, Ed.; Walberg, Herbert J., Ed.

    2009-01-01

    Since the early 1990s when the nation's first charter school was opened in Minneapolis, the scope and availability of school-based options to parents has steadily expanded. No longer can public education be characterized as a monopoly. Sponsored by the National Center on School Choice (NCSC), this handbook makes readily available the most rigorous…

  19. Understanding Adolescent Contraceptive Choice: An Empirical Test.

    ERIC Educational Resources Information Center

    Adler, Nancy E.; And Others

    Research using expectancy models has shown contraceptive choice among adults to be a rational process in that intentions and behaviors reflect an individual's beliefs, values, attitudes, and perceptions of social norms. This study examined whether such an approach could accurately represent adolescents' contraceptive decision-making. It used the…

  20. Subjects of Choice and Lifelong Learning

    ERIC Educational Resources Information Center

    Bansel, Peter

    2007-01-01

    This paper addresses some of the discursive practices of neoliberal government through which the subject is constituted as a subject of choice--subjects whose life trajectory is shaped by the imperatives of a labour market in which they will become mobile and flexible workers with multiple careers and jobs. Mobility among these multiple careers…

  1. Choice of For-Profit College

    ERIC Educational Resources Information Center

    Chung, Anna S.

    2012-01-01

    In this paper I investigate whether students self-select into the U.S. for-profit colleges or whether the choice of for-profit sector is accidental or due to the reasons external to the students (geographic exposure to for-profit providers, tuition pricing, or random circumstances). The main student-level data samples come from the National…

  2. Action and valence modulate choice and choice-induced preference change.

    PubMed

    Koster, Raphael; Duzel, Emrah; Dolan, Raymond J

    2015-01-01

    Choices are not only communicated via explicit actions but also passively through inaction. In this study we investigated how active or passive choice impacts upon the choice process itself as well as a preference change induced by choice. Subjects were tasked to select a preference for unfamiliar photographs by action or inaction, before and after they gave valuation ratings for all photographs. We replicate a finding that valuation increases for chosen items and decreases for unchosen items compared to a control condition in which the choice was made post re-evaluation. Whether choice was expressed actively or passively affected the dynamics of revaluation differently for positive and negatively valenced items. Additionally, the choice itself was biased towards action such that subjects tended to choose a photograph obtained by action more often than a photographed obtained through inaction. These results highlight intrinsic biases consistent with a tight coupling of action and reward and add to an emerging understanding of how the mode of action itself, and not just an associated outcome, modulates the decision making process.

  3. GluN2B in corticostriatal circuits governs choice learning and choice shifting.

    PubMed

    Brigman, Jonathan L; Daut, Rachel A; Wright, Tara; Gunduz-Cinar, Ozge; Graybeal, Carolyn; Davis, Margaret I; Jiang, Zhihong; Saksida, Lisa M; Jinde, Seiichiro; Pease, Matthew; Bussey, Timothy J; Lovinger, David M; Nakazawa, Kazu; Holmes, Andrew

    2013-08-01

    A choice that reliably produces a preferred outcome can be automated to liberate cognitive resources for other tasks. Should an outcome become less desirable, behavior must adapt in parallel or it becomes perseverative. Corticostriatal systems are known to mediate choice learning and flexibility, but the molecular mechanisms of these processes are not well understood. We integrated mouse behavioral, immunocytochemical, in vivo electrophysiological, genetic and pharmacological approaches to study choice. We found that the dorsal striatum (DS) was increasingly activated with choice learning, whereas reversal of learned choice engaged prefrontal regions. In vivo, DS neurons showed activity associated with reward anticipation and receipt that emerged with learning and relearning. Corticostriatal or striatal deletion of Grin2b (encoding the NMDA-type glutamate receptor subunit GluN2B) or DS-restricted GluN2B antagonism impaired choice learning, whereas cortical Grin2b deletion or OFC GluN2B antagonism impaired shifting. Our convergent data demonstrate how corticostriatal GluN2B circuits govern the ability to learn and shift choice behavior.

  4. Route choice in pedestrians: determinants for initial choices and revising decisions.

    PubMed

    Liao, Weichen; Kemloh Wagoum, Armel U; Bode, Nikolai W F

    2017-02-01

    In moving pedestrian crowds, the distribution of individuals over different available routes emerges from the decisions of individuals that may be influenced by the actions of others. Understanding this phenomenon not only is important for research into collective behaviour, but also has practical applications for building safety and event management. Here, we study the mechanisms underlying pedestrian route choice, focusing on how time-independent information, such as path lengths, and time-dependent information, such as queue lengths, affect both initial decisions and subsequent changes in route choices. We address these questions using experiments with nearly 140 volunteers and an individual-based model for route choice. Crucially, we consider a wide range of route choice scenarios. We find that initial route choices of pedestrians achieve a balanced usage of available routes. Our model suggests that pedestrians performing trade-offs between exit widths and predicted exit crowdedness can explain this emergent distribution in many contexts. Few pedestrians adjust their route choice in our experiments. Simulations suggest that these decisions could be explained by pedestrians comparing estimates of the time it would take them to reach their target using different routes. Route choice is complex, but our findings suggest that conceptually simple behaviours may explain many movement decisions.

  5. The ABCs of School Choice: The Comprehensive Guide to Every Private School Choice Program in America. 2016 Edition

    ERIC Educational Resources Information Center

    Friedman Foundation for Educational Choice, 2016

    2016-01-01

    "The ABCs of School Choice" is a comprehensive, data-rich guide to every private school choice program in America. The 2016 edition of "The ABCs of School Choice" is the best yet, not just because of the new look and the fantastic growth in the number of school choice programs, but also because it is now paired with a…

  6. How Many Choices Are Good? Measurement of the Effects of Course Choice on Perceptions of a Marketing Option

    ERIC Educational Resources Information Center

    Ackerman, David S.; Gross, Barbara L.

    2006-01-01

    This study examines the effects of amount of choice given students in selecting courses to complete a marketing minor, referred to as a marketing option. It examines how differing levels of choice can affect perceptions of, and feelings about, a marketing option. The course choice process is also explored. The impact of choice on students' desire…

  7. Some Remarks on the Choice of Ductility Class for Earthquake-Resistant Steel Structures

    NASA Astrophysics Data System (ADS)

    Matejčeková-Farhat, Miroslava; Ároch, Rudolf

    2013-09-01

    The implementation of the Eurocodes in current structural design practice has brought about a new emphasis on the design of earthquake-resistant structures. In some European countries, new earthquake zones have been defined; henceforth, the design requirements of many ongoing projects have changed as well. The choice of the ductility class of steel structures as one of the key design parameters, the consequences of this choice on design procedure, and some applications of the Eurocode 8 design criteria by comparing French and Slovak national practice are discussed, using a practical example of a structure.

  8. Patient-specific parameter estimation in single-ventricle lumped circulation models under uncertainty.

    PubMed

    Schiavazzi, Daniele E; Baretta, Alessia; Pennati, Giancarlo; Hsia, Tain-Yen; Marsden, Alison L

    2017-03-01

    Computational models of cardiovascular physiology can inform clinical decision-making, providing a physically consistent framework to assess vascular pressures and flow distributions, and aiding in treatment planning. In particular, lumped parameter network (LPN) models that make an analogy to electrical circuits offer a fast and surprisingly realistic method to reproduce the circulatory physiology. The complexity of LPN models can vary significantly to account, for example, for cardiac and valve function, respiration, autoregulation, and time-dependent hemodynamics. More complex models provide insight into detailed physiological mechanisms, but their utility is maximized if one can quickly identify patient specific parameters. The clinical utility of LPN models with many parameters will be greatly enhanced by automated parameter identification, particularly if parameter tuning can match non-invasively obtained clinical data. We present a framework for automated tuning of 0D lumped model parameters to match clinical data. We demonstrate the utility of this framework through application to single ventricle pediatric patients with Norwood physiology. Through a combination of local identifiability, Bayesian estimation and maximum a posteriori simplex optimization, we show the ability to automatically determine physiologically consistent point estimates of the parameters and to quantify uncertainty induced by errors and assumptions in the collected clinical data. We show that multi-level estimation, that is, updating the parameter prior information through sub-model analysis, can lead to a significant reduction in the parameter marginal posterior variance. We first consider virtual patient conditions, with clinical targets generated through model solutions, and second application to a cohort of four single-ventricle patients with Norwood physiology. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Methods of optimal control choice of non-Keplerian orbits

    NASA Astrophysics Data System (ADS)

    Starinova, Olga

    2017-01-01

    The developed method of iterative optimization of interplanetary missions with the low thrust, using sequence of movement specified mathematical models and design shape spacecraft, is realized. The new articular analytical decision describing planar movement of spacecraft with solar electric propulsion is described, allowing to construct initial approach in the iterative scheme of optimization. Developed a method of modelling and optimization of interplanetary missions ballistic schemes, based on a combination of Pontryagin's maximum principle formalism conditions of transversality and methods of the mathematical programming, allowing to consider restrictions characteristic for concrete interplanetary missions. Recommendations for choice design-ballistic parameters of the interplanetary missions spacecraft, received taking into account features nuclear and solar power plant for missions on delivery of a payload to orbits of Mars, expeditions the Earth-Mars-Earth are received.

  10. Choices at Space Station End of Life

    NASA Astrophysics Data System (ADS)

    Burke, J. D.; Coderre, K. M.; Dator, J. A.

    Extending International Space Station (ISS) operations will expand the scope for deciding its fate at its end of life. In this paper we examine the choices likely to be available at that distant unknown day when it is decided, for whatever reasons, to bring crew-directed engineering and science operations to a close. Of course a premature accidental termination is possible at any time, and measures to cope with that (and return to normal if possible) should be kept ready and augmented as ISS service capacities improve, but here we do not focus on accidents. Rather, we consider what may be done with an old but functioning spacecraft after it is declared surplus. We use the technique of Futures Studies to look at the choices. Without attempting prediction, futurists develop a set of empirically-based alternate futures, describe the likely consequences of each, and point to preferred outcomes. For the ISS at end of scheduled operation the choices are in three classes: DOWN, STAY, or UP. In the DOWN choice, after possible salvage and transfer of long-running investigations to another (e.g., Chinese-led) international station, the ISS is commanded to descend and burn up. The STAY choice, not viable in the long run, might be chosen to provide time for later decisions, but eventually it would prove impractical to continue re-boosting to maintain the station in Low Earth Orbit (LEO). In the UP choice the ISS is propelled, by heavy-lift boost impulses or a low-thrust spiral-out or a combination of both, into a high orbit with a lifetime of hundreds of years, opening the prospect of a wide variety of options to be compared in search of a preferred longer-term future. The decision to boost the ISS into a high orbit could be completely rational based on any of several arguments, or it could be partly irrational as in the case of the USS Constitution, an eighteenth- century warship saved from the ship-breakers by a poem.

  11. Behavioral Economics and the Supplemental Nutrition Assistance Program:: Making the Healthy Choice the Easy Choice.

    PubMed

    Ammerman, Alice S; Hartman, Terry; DeMarco, Molly M

    2017-02-01

    The Supplemental Nutrition Assistance Program (SNAP) serves as an important nutritional safety net program for many Americans. Given its aim to use traditional economic levers to provide access to food, the SNAP program includes minimal nutritional requirements and restrictions. As food choices are influenced by more than just economic constraints, behavioral economics may offer insights and tools for altering food purchases for SNAP users. This manuscript outlines behavioral economics strategies that have potential to encourage healthier food choices within the SNAP program.

  12. Choice ball: a response interface for two-choice psychometric discrimination in head-fixed mice.

    PubMed

    Sanders, Joshua I; Kepecs, Adam

    2012-12-01

    The mouse is an important model system for investigating the neural circuits mediating behavior. Because of advances in imaging and optogenetic methods, head-fixed mouse preparations provide an unparalleled opportunity to observe and control neural circuits. To investigate how neural circuits produce behavior, these methods need to be paired with equally well-controlled and monitored behavioral paradigms. Here, we introduce the choice ball, a response device that enables two-alternative forced-choice (2AFC) tasks in head-fixed mice based on the readout of lateral paw movements. We demonstrate the advantages of the choice ball by training mice in the random-click task, a two-choice auditory discrimination behavior. For each trial, mice listened to binaural streams of Poisson-distributed clicks and were required to roll the choice ball laterally toward the side with the greater click rate. In this assay, mice performed hundreds of trials per session with accuracy ranging from 95% for easy stimuli (large interaural click-rate contrast) to near chance level for low-contrast stimuli. We also show, using the record of individual paw strokes, that mice often reverse decisions they have already initiated and that decision reversals correlate with improved performance. The choice ball enables head-fixed 2AFC paradigms, facilitating the circuit-level analysis of sensory processing, decision making, and motor control in mice.

  13. An integrated model of choices and response times in absolute identification.

    PubMed

    Brown, Scott D; Marley, A A J; Donkin, Christopher; Heathcote, Andrew

    2008-04-01

    Recent theoretical developments in the field of absolute identification have stressed differences between relative and absolute processes, that is, whether stimulus magnitudes are judged relative to a shorter term context provided by recently presented stimuli or a longer term context provided by the entire set of stimuli. The authors developed a model (SAMBA: selective attention, mapping, and ballistic accumulation) that integrates shorter and longer term memory processes and accounts for both the choices made and the associated response time distributions, including sequential effects in each. The model's predictions arise as a consequence of its architecture and require estimation of only a few parameters with values that are consistent across numerous data sets. The authors show that SAMBA provides a quantitative account of benchmark choice phenomena in classical absolute identification experiments and in contemporary data involving both choice and response time.

  14. Do framing effects reveal irrational choice?

    PubMed

    Mandel, David R

    2014-06-01

    Framing effects have long been viewed as compelling evidence of irrationality in human decision making, yet that view rests on the questionable assumption that numeric quantifiers used to convey the expected values of choice options are uniformly interpreted as exact values. Two experiments show that when the exactness of such quantifiers is made explicit by the experimenter, framing effects vanish. However, when the same quantifiers are given a lower bound (at least) meaning, the typical framing effect is found. A 3rd experiment confirmed that most people spontaneously interpret the quantifiers in standard framing tests as lower bounded and that their interpretations strongly moderate the framing effect. Notably, in each experiment, a significant majority of participants made rational choices, either choosing the option that maximized expected value (i.e., lives saved) or choosing consistently across frames when the options were of equal expected value.

  15. Mate choice for optimal (k)inbreeding.

    PubMed

    Puurtinen, Mikael

    2011-05-01

    Mating between related individuals results in inbreeding depression, and this has been thought to select against incestuous matings. However, theory predicts that inbreeding can also be adaptive if it increases the representation of genes identical by descent in future generations. Here, I recapitulate the theory of inclusive fitness benefits of incest, and extend the existing theory by deriving the stable level of inbreeding in populations practicing mate choice for optimal inbreeding. The parsimonious assumptions of the model are that selection maximizes inclusive fitness, and that inbreeding depression is a linear function of homozygosity of offspring. The stable level of inbreeding that maximizes inclusive fitness, and is expected to evolve by natural selection, is shown to be less than previous theory suggests. For wide range of realistic inbreeding depression strengths, mating with intermediately related individuals maximizes inclusive fitness. The predicted preference for intermediately related individuals as reproductive partners is in qualitative agreement with empirical evidence from mate choice experiments and reproductive patterns in nature.

  16. Consumer choice of pork chops in Taiwan.

    PubMed

    Chen, M T; Guo, H L; Tseng, T F; Roan, S W; Ngapo, T M

    2010-07-01

    Digital photographs of pork chops varying systematically in appearance were presented to 716 Taiwanese consumers in a study that aimed to identify the most important characteristics of fresh pork which determine consumer choice in Taiwan. Relationships between consumer segmentation in choice and socio-demographic and cultural differences were also investigated. Colour and fat cover were the most frequently chosen of the four characteristics studied. Dark red colour was preferred by 64% of consumers and lean fat cover by 44%. Marbling and drip were less important in the decision making process being used by less than a half of consumers. The four preference-based clusters of consumers showed no correlation with socio-demographic-based consumer clusters, but did show significant links with possession of a refrigerator, age at which schooling was completed, liking pork for its price and gender of consumer.

  17. Sustainable food consumption. Product choice or curtailment?

    PubMed

    Verain, Muriel C D; Dagevos, Hans; Antonides, Gerrit

    2015-08-01

    Food consumption is an important factor in shaping the sustainability of our food supply. The present paper empirically explores different types of sustainable food behaviors. A distinction between sustainable product choices and curtailment behavior has been investigated empirically and predictors of the two types of behavior have been identified. Respondents were classified into four segments based on their sustainable food behaviors: unsustainers, curtailers, product-oriented consumers, and sustainers. Significant differences between the segments were found with regard to food choice motives, personal and social norms, food involvement, subjective knowledge on sustainable food, ability to judge how sustainably a product has been produced and socio-demographics. It is concluded that distinguishing between behavioral strategies toward sustainable food consumption is important as consumer segments can be identified that differ both in their level of sustainable food consumption and in the type of behavior they employ.

  18. INJECTION CHOICE FOR SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; BRODOWSKI,J.; FEDOTOV,A.; GARDNER,C.; LEE,Y.Y.; RAPARIA,D.; DANILOV,V.; HOLMES,J.; PRIOR,C.; REES,G.; MACHIDA,S.

    2001-06-18

    Injection is key in the low-loss design of high-intensity proton facilities like the Spallation Neutron Source (SNS). During the design of both the accumulator and the rapid-cycling-synchrotron version of the SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's low-loss design criteria. This paper presents issues and considerations pertaining to the final choice of the SNS injection systems.

  19. Shared decision making, paternalism and patient choice.

    PubMed

    Sandman, Lars; Munthe, Christian

    2010-03-01

    In patient centred care, shared decision making is a central feature and widely referred to as a norm for patient centred medical consultation. However, it is far from clear how to distinguish SDM from standard models and ideals for medical decision making, such as paternalism and patient choice, and e.g., whether paternalism and patient choice can involve a greater degree of the sort of sharing involved in SDM and still retain their essential features. In the article, different versions of SDM are explored, versions compatible with paternalism and patient choice as well as versions that go beyond these traditional decision making models. Whenever SDM is discussed or introduced it is of importance to be clear over which of these different versions are being pursued, since they connect to basic values and ideals of health care in different ways. It is further argued that we have reason to pursue versions of SDM involving, what is called, a high level dynamics in medical decision-making. This leaves four alternative models to choose between depending on how we balance between the values of patient best interest, patient autonomy, and an effective decision in terms of patient compliance or adherence: Shared Rational Deliberative Patient Choice, Shared Rational Deliberative Paternalism, Shared Rational Deliberative Joint Decision, and Professionally Driven Best Interest Compromise. In relation to these models it is argued that we ideally should use the Shared Rational Deliberative Joint Decision model. However, when the patient and professional fail to reach consensus we will have reason to pursue the Professionally Driven Best Interest Compromise model since this will best harmonise between the different values at stake: patient best interest, patient autonomy, patient adherence and a continued care relationship.

  20. Household location choices: implications for biodiversity conservation.

    PubMed

    Peterson, M Nils; Chen, Xiaodong; Liu, Jianguo

    2008-08-01

    Successful conservation efforts require understanding human behaviors that directly affect biodiversity. Choice of household location represents an observable behavior that has direct effects on biodiversity conservation, but no one has examined the sociocultural predictors of this choice relative to its environmental impacts. We conducted a case study of the Teton Valley of Idaho and Wyoming (U.S.A.) that (1) explored relationships between sociodemographic variables, environmental attitudes, and the environmental impact of household location choices, (2) assessed the potential for small household sizes in natural areas to multiply the environmental impacts of household location decisions, and (3) evaluated how length of residency predicted the environmental attitudes of people living in natural areas. We collected sociodemographic data, spatial coordinates, and land-cover information in a survey of 416 households drawn from a random sample of Teton Valley residents (95% compliance rate). Immigrants (respondents not born in the study area) with the lowest education levels and least environmentally oriented attitudes lived in previously established residential areas in disproportionately high numbers, and older and more educated immigrants with the most environmentally oriented attitudes lived in natural areas in disproportionately high numbers. Income was not a significant predictor of household location decisions. Those living in natural areas had more environmental impact per person because of the location and because small households (<3 people/household) were 4 times as likely in natural areas as large households. Longer residency in natural areas predicted less environmentally oriented attitudes, suggesting that living in natural areas does not foster more concern for nature. Because populaces are rapidly aging, growing more educated, and potentially growing more environmentally oriented, these patterns are troubling for biodiversity conservation. Our results

  1. Redefining solubility parameters: the partial solvation parameters.

    PubMed

    Panayiotou, Costas

    2012-03-21

    The present work reconsiders a classical and universally accepted concept of physical chemistry, the solubility parameter. Based on the insight derived from modern quantum chemical calculations, a new definition of solubility parameter is proposed, which overcomes some of the inherent restrictions of the original definition and expands its range of applications. The original single solubility parameter is replaced by four partial solvation parameters reflecting the dispersion, the polar, the acidic and the basic character of the chemical compounds as expressed either in their pure state or in mixtures. Simple rules are adopted for the definition and calculation of these four parameters and their values are tabulated for a variety of common substances. In contrast, however, to the well known Hansen solubility parameters, their design and evaluation does not rely exclusively on the basic rule of "similarity matching" for solubility but it makes also use of the other basic rule of compatibility, namely, the rule of "complementarity matching". This complementarity matching becomes particularly operational with the sound definition of the acidic and basic components of the solvation parameter based on the third σ-moments of the screening charge distributions of the quantum mechanics-based COSMO-RS theory. The new definitions are made in a simple and straightforward manner, thus, preserving the strength and appeal of solubility parameter stemming from its simplicity. The new predictive method has been applied to a variety of solubility data for systems of pharmaceuticals and polymers. The results from quantum mechanics calculations are critically compared with the results from Abraham's acid/base descriptors.

  2. Honey bees selectively avoid difficult choices.

    PubMed

    Perry, Clint J; Barron, Andrew B

    2013-11-19

    Human decision-making strategies are strongly influenced by an awareness of certainty or uncertainty (a form of metacognition) to increase the chances of making a right choice. Humans seek more information and defer choosing when they realize they have insufficient information to make an accurate decision, but whether animals are aware of uncertainty is currently highly contentious. To explore this issue, we examined how honey bees (Apis mellifera) responded to a visual discrimination task that varied in difficulty between trials. Free-flying bees were rewarded for a correct choice, punished for an incorrect choice, or could avoid choosing by exiting the trial (opting out). Bees opted out more often on difficult trials, and opting out improved their proportion of successful trials. Bees could also transfer the concept of opting out to a novel task. Our data show that bees selectively avoid difficult tasks they lack the information to solve. This finding has been considered as evidence that nonhuman animals can assess the certainty of a predicted outcome, and bees' performance was comparable to that of primates in a similar paradigm. We discuss whether these behavioral results prove bees react to uncertainty or whether associative mechanisms can explain such findings. To better frame metacognition as an issue for neurobiological investigation, we propose a neurobiological hypothesis of uncertainty monitoring based on the known circuitry of the honey bee brain.

  3. Sensitivity, changeover responses, and choice in transition.

    PubMed

    Jiménez, Angel A; Aparicio, Carlos F

    2009-09-01

    Studies of choice in steady state have shown that sensitivity to reinforcement increases with increasing fixed-ratio changeover (FR CO) requirements. We assessed the generality of this finding with choice in transition. Food deliveries were programmed according to concurrent variable-interval (VI) schedules. Seven different VI pairs arranged ratios of food deliveries (left/right) of 27:1, 9:1, 3:1, 1:1, 1:3, 1:9, and 1:27 at a constant overall rate across components. Within sessions, all seven ratios were presented in random order. Each component lasted for 10 food deliveries; components were separated by 60-s blackouts. A changeover lever required 1, 2, 4, 8, 16, 32, and 64 responses to alternate between two main levers. Redeterminations to all FR COs, but 64 responses, were obtained in descending order. Choice adjusted rapidly to rapid changes in the reinforcer ratio, tracking the lever associated with the highest probability of reinforcer. Sensitivity to reinforcement increased with increasing FR CO, replicating the negatively accelerated function found in our earlier study. With successive reinforcers in components, however, sensitivity reached asymptote values sooner with the largest (8, 16, and 32 responses), than with the smallest (1, 2, and 4 responses), FR CO requirements.

  4. Choices enhance punching performance of competitive kickboxers.

    PubMed

    Halperin, Israel; Chapman, Dale W; Martin, David T; Lewthwaite, Rebecca; Wulf, Gabriele

    2016-07-27

    While self-controlled practice has been shown to enhance motor learning with various populations and novel tasks, it remains unclear if such effects would be found with athletes completing familiar tasks. Study 1 used a single case-study design with a world-champion kickboxer. We investigated whether giving the athlete a choice over the order of punches would affect punching velocity and impact force. Separated by 1 min of rest, the athlete completed 2 rounds of 12 single, maximal effort punches (lead straight, rear straight, lead hook and rear hook) delivered to a punching integrator in a counterbalanced order over six testing days. In one round the punches were delivered in a predetermined order while in the second round the order was self-selected by the athlete. In the choice condition, the world champion punched with greater velocities (6-11 %) and impact forces (5-10 %). In Study 2, the same testing procedures were repeated with 13 amateur male kickboxers over 2 testing days. Similar to Study 1, the athletes punched with significantly greater velocities (6 %, p < 0.05) and normalised impact forces (2 %, p < 0.05) in the choice condition. These findings complement research on autonomy support in motor learning by demonstrating immediate advantages in force production and velocity with experienced athletes.

  5. Air Cargo Transportation Route Choice Analysis

    NASA Technical Reports Server (NTRS)

    Obashi, Hiroshi; Kim, Tae-Seung; Oum, Tae Hoon

    2003-01-01

    Using a unique feature of air cargo transshipment data in the Northeast Asian region, this paper identifies the critical factors that determine the transshipment route choice. Taking advantage of the variations in the transport characteristics in each origin-destination airports pair, the paper uses a discrete choice model to describe the transshipping route choice decision made by an agent (i.e., freight forwarder, consolidator, and large shipper). The analysis incorporates two major factors, monetary cost (such as line-haul cost and landing fee) and time cost (i.e., aircraft turnaround time, including loading and unloading time, custom clearance time, and expected scheduled delay), along with other controls. The estimation method considers the presence of unobserved attributes, and corrects for resulting endogeneity by use of appropriate instrumental variables. Estimation results find that transshipment volumes are more sensitive to time cost, and that the reduction in aircraft turnaround time by 1 hour would be worth the increase in airport charges by more than $1000. Simulation exercises measures the impacts of alternative policy scenarios for a Korean airport, which has recently declared their intention to be a future regional hub in the Northeast Asian region. The results suggest that reducing aircraft turnaround time at the airport be an effective strategy, rather than subsidizing to reduce airport charges.

  6. Arbitration between controlled and impulsive choices

    PubMed Central

    Economides, M.; Guitart-Masip, M.; Kurth-Nelson, Z.; Dolan, R.J.

    2015-01-01

    The impulse to act for immediate reward often conflicts with more deliberate evaluations that support long-term benefit. The neural architecture that negotiates this conflict remains unclear. One account proposes a single neural circuit that evaluates both immediate and delayed outcomes, while another outlines separate impulsive and patient systems that compete for behavioral control. Here we designed a task in which a complex payout structure divorces the immediate value of acting from the overall long-term value, within the same outcome modality. Using model-based fMRI in humans, we demonstrate separate neural representations of immediate and long-term values, with the former tracked in the anterior caudate (AC) and the latter in the ventromedial prefrontal cortex (vmPFC). Crucially, when subjects' choices were compatible with long-run consequences, value signals in AC were down-weighted and those in vmPFC were enhanced, while the opposite occurred when choice was impulsive. Thus, our data implicate a trade-off in value representation between AC and vmPFC as underlying controlled versus impulsive choice. PMID:25573670

  7. Model for understanding consumer textural food choice.

    PubMed

    Jeltema, Melissa; Beckley, Jacqueline; Vahalik, Jennifer

    2015-05-01

    The current paradigm for developing products that will match the marketing messaging is flawed because the drivers of product choice and satisfaction based on texture are misunderstood. Qualitative research across 10 years has led to the thesis explored in this research that individuals have a preferred way to manipulate food in their mouths (i.e., mouth behavior) and that this behavior is a major driver of food choice, satisfaction, and the desire to repurchase. Texture, which is currently thought to be a major driver of product choice, is a secondary factor, and is important only in that it supports the primary driver-mouth behavior. A model for mouth behavior is proposed and the qualitative research supporting the identification of different mouth behaviors is presented. The development of a trademarked typing tool for characterizing mouth behavior is described along with quantitative substantiation of the tool's ability to group individuals by mouth behavior. The use of these four groups to understand textural preferences and the implications for a variety of areas including product design and weight management are explored.

  8. Model for understanding consumer textural food choice

    PubMed Central

    Jeltema, Melissa; Beckley, Jacqueline; Vahalik, Jennifer

    2015-01-01

    The current paradigm for developing products that will match the marketing messaging is flawed because the drivers of product choice and satisfaction based on texture are misunderstood. Qualitative research across 10 years has led to the thesis explored in this research that individuals have a preferred way to manipulate food in their mouths (i.e., mouth behavior) and that this behavior is a major driver of food choice, satisfaction, and the desire to repurchase. Texture, which is currently thought to be a major driver of product choice, is a secondary factor, and is important only in that it supports the primary driver—mouth behavior. A model for mouth behavior is proposed and the qualitative research supporting the identification of different mouth behaviors is presented. The development of a trademarked typing tool for characterizing mouth behavior is described along with quantitative substantiation of the tool's ability to group individuals by mouth behavior. The use of these four groups to understand textural preferences and the implications for a variety of areas including product design and weight management are explored. PMID:25987995

  9. A Comment On Birnbaum's Three-Parameter Logistic Model In The Latent Trait Theory

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    1973-01-01

    The three-parameter logistic model by Birnbaum for the multiple-choice item in the latent trait theory is considered with respect to the item response information function and the unique maximum condition. (Editor/RK)

  10. Water surface area and depth determine oviposition choice in Aedes albopictus (Diptera: Culicidae).

    PubMed

    Reiskind, Michael H; Zarrabi, Ali A

    2012-01-01

    Oviposition choice is a well-studied aspect of the mosquito life cycle, and offers a potential avenue for species-specific surveillance and control. In container inhabiting mosquitoes, there has been a focus on how the components of the aquatic media determine choice, with little work on the physical characteristics of the containers themselves. We performed five experiments examining the effect of physical container parameters on oviposition choice by Aedes albopictus. We examined containers of three different surface areas (small, 496 cm2; medium, 863 cm2; and large, 1,938 cm2) at the same water depth and the same or different heights in a series of binary choice assays. We also examined different depths with the same surface area in clear containers (where the depth may be perceived by the darkness of the water) and in opaque containers, which appear uniformly dark at different depths. We found a significant preference for medium containers over large containers, whether the containers were different or the same heights, and a trend toward a preference for small containers over medium containers. There was a preference for deeper water regardless of whether containers were clear or opaque. These behaviors suggest mosquitoes take into account physical aspects of their habitats and their oviposition choices are consistent with minimizing the risk of habitat drying.

  11. A likelihood-based biostatistical model for analyzing consumer movement in simultaneous choice experiments.

    PubMed

    Zeilinger, Adam R; Olson, Dawn M; Andow, David A

    2014-08-01

    Consumer feeding preference among resource choices has critical implications for basic ecological and evolutionary processes, and can be highly relevant to applied problems such as ecological risk assessment and invasion biology. Within consumer choice experiments, also known as feeding preference or cafeteria experiments, measures of relative consumption and measures of consumer movement can provide distinct and complementary insights into the strength, causes, and consequences of preference. Despite the distinct value of inferring preference from measures of consumer movement, rigorous and biologically relevant analytical methods are lacking. We describe a simple, likelihood-based, biostatistical model for analyzing the transient dynamics of consumer movement in a paired-choice experiment. With experimental data consisting of repeated discrete measures of consumer location, the model can be used to estimate constant consumer attraction and leaving rates for two food choices, and differences in choice-specific attraction and leaving rates can be tested using model selection. The model enables calculation of transient and equilibrial probabilities of consumer-resource association, which could be incorporated into larger scale movement models. We explore the effect of experimental design on parameter estimation through stochastic simulation and describe methods to check that data meet model assumptions. Using a dataset of modest sample size, we illustrate the use of the model to draw inferences on consumer preference as well as underlying behavioral mechanisms. Finally, we include a user's guide and computer code scripts in R to facilitate use of the model by other researchers.

  12. TADtool: visual parameter identification for TAD-calling algorithms.

    PubMed

    Kruse, Kai; Hug, Clemens B; Hernández-Rodríguez, Benjamín; Vaquerizas, Juan M

    2016-10-15

    Eukaryotic genomes are hierarchically organized into topologically associating domains (TADs). The computational identification of these domains and their associated properties critically depends on the choice of suitable parameters of TAD-calling algorithms. To reduce the element of trial-and-error in parameter selection, we have developed TADtool: an interactive plot to find robust TAD-calling parameters with immediate visual feedback. TADtool allows the direct export of TADs called with a chosen set of parameters for two of the most common TAD calling algorithms: directionality and insulation index. It can be used as an intuitive, standalone application or as a Python package for maximum flexibility.

  13. 75 FR 68169 - Participants' Choices of TSP Funds

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-05

    ... Part 1601 Participants' Choices of TSP Funds AGENCY: Federal Retirement Thrift Investment Board. ACTION... 1601--PARTICIPANTS' CHOICES OF TSP FUNDS 0 1. The authority citation for part 1601 continues to read...

  14. The role of word choice and criterion on intentional memory.

    PubMed

    Toyota, Hiroshi

    2015-02-01

    The relationship between the criterion for choosing and the self-choice effects (greater recall in a self-choice compared to a forced-choice condition) on intentional memory was examined. Thirty-three female nursing school volunteers were administered 24 word pairs in a 2 × 2 design to assess the influence of motivation upon free recall. When word pairs were presented to participants, they were asked to choose a word to-be-remembered, either in a self-choice condition or a forced-choice condition. Words chosen by the participants were recalled more often than those chosen by the experimenter (forced choice). Thus, the self-choice effect was greater for words chosen with a self-reference criterion compared to a metamemory criterion, supporting the integration hypothesis as the origin of the self-choice effect.

  15. The Relationship between Congruent Specialty Choice within Occupations and Satisfaction.

    ERIC Educational Resources Information Center

    Meir, Elchanan I.; Yaari, Yael

    1988-01-01

    Examined hypothesis that relationship between congruent specialty choice within occupations and satisfaction exceeds relationship between congruent occupational choice and satisfaction. Responses from 324 engineers, physicians, nurses, teachers, policemen, biologists, lawyers, and psychologists to appropriate within-occupation interest inventories…

  16. Autonomous mechanism of internal choice estimate underlies decision inertia.

    PubMed

    Akaishi, Rei; Umeda, Kazumasa; Nagase, Asako; Sakai, Katsuyuki

    2014-01-08

    Our choice is influenced by choices we made in the past, but the mechanism responsible for the choice bias remains elusive. Here we show that the history-dependent choice bias can be explained by an autonomous learning rule whereby an estimate of the likelihood of a choice to be made is updated in each trial by comparing between the actual and expected choices. We found that in perceptual decision making without performance feedback, a decision on an ambiguous stimulus is repeated on the subsequent trial more often than a decision on a salient stimulus. This inertia of decision was not accounted for by biases in motor response, sensory processing, or attention. The posterior cingulate cortex and frontal eye field represent choice prediction error and choice estimate in the learning algorithm, respectively. Interactions between the two regions during the intertrial interval are associated with decision inertia on a subsequent trial.

  17. The Susceptibility of Item Parameters to Instructions for Completion.

    ERIC Educational Resources Information Center

    McDonald, Jo-Anne

    The purpose of this study was to examine the effect of completion instructions on item parameters and category use as students completed a self-report personality survey. Instructions allowed free-choice allotment of ratings (nonforced distribution) or requested the subject to assign a certain number of ratings to either the highest or lowest…

  18. Alternative Weights and Invariant Parameters in Optimal Scaling.

    ERIC Educational Resources Information Center

    McDonald, Roderick P.

    1983-01-01

    Under conditions commonly met in optimal scaling problems, arbitrary sets of optimal weights can be obtained by choices of generalized universe scores. It is suggested that the invariant parameters of optimal scaling should be interpreted according to latent trait theory, rather than the arbitrary weights. (Author/JKS)

  19. Choice from non-choice: Predicting consumer preferences from BOLD signals obtained during passive viewing

    PubMed Central

    Levy, Ifat; Lazzaro, Stephanie C.; Rutledge, Robb B.; Glimcher, Paul W.

    2011-01-01

    Decision-making is often viewed as a two-stage process, where subjective values are first assigned to each option and then the option of the highest value is selected. Converging evidence suggests that these subjective values are represented in the striatum and medial prefrontal cortex (MPFC). A separate line of evidence suggests that activation in the same areas represents the values of rewards even when choice is not required, as in classical conditioning tasks. However, it is unclear whether the same neural mechanism is engaged in both cases. To address this question we measured brain activation with fMRI while human subjects passively viewed individual consumer goods. We then sampled activation from predefined regions of interest and used it to predict subsequent choices between the same items made outside of the scanner. Our results show that activation in the striatum and MPFC in the absence of choice predicts subsequent choices, suggesting that these brain areas represent value in a similar manner whether or not choice is required. PMID:21209196

  20. Asymmetry of reinforcement and punishment in human choice.

    PubMed

    Rasmussen, Erin B; Newland, M Christopher

    2008-03-01

    The hypothesis that a penny lost is valued more highly than a penny earned was tested in human choice. Five participants clicked a computer mouse under concurrent variable-interval schedules of monetary reinforcement. In the no-punishment condition, the schedules arranged monetary gain. In the punishment conditions, a schedule of monetary loss was superimposed on one response alternative. Deviations from generalized matching using the free parameters c (sensitivity to reinforcement) and log k (bias) were compared in the no-punishment and punishment conditions. The no-punishment conditions yielded values of log k that approximated zero for all participants, indicating no bias. In the punishment condition, values of log k deviated substantially from zero, revealing a 3-fold bias toward the unpunished alternative. Moreover, the c parameters were substantially smaller in punished conditions. The values for bias and sensitivity under punishment did not change significantly when the measure of net reinforcers (gains minus losses) was applied to the analysis. These results mean that punishment reduced the sensitivity of behavior to reinforcement and biased performance toward the unpunished alternative. We concluded that a single punisher subtracted more value than a single reinforcer added, indicating an asymmetry in the law of effect.

  1. Study of the Voluntary Public School Choice Program. Final Report

    ERIC Educational Resources Information Center

    Yin, Robert K.; Ahonen, Pirkko S.

    2008-01-01

    The Voluntary Public School Choice (VPSC) Program supports the emergence and growth of choice initiatives across the country, by assisting states and local school districts in developing innovative strategies to expand public school choice options for students. This report contains the final assessment of the first five years of the VPSC Program…

  2. Public Choice, Market Failure, and Government Failure in Principles Textbooks

    ERIC Educational Resources Information Center

    Fike, Rosemarie; Gwartney, James

    2015-01-01

    Public choice uses the tools of economics to analyze how the political process allocates resources and impacts economic activity. In this study, the authors examine twenty-three principles texts regarding coverage of public choice, market failure, and government failure. Approximately half the texts provide coverage of public choice and recognize…

  3. School Choice and Educational Opportunity: Rationales, Outcomes and Racial Disparities

    ERIC Educational Resources Information Center

    Ben-Porath, Sigal

    2012-01-01

    This article examines the rationales for school choice, and the significance of choice mechanisms for racial disparities in educational opportunities and outcomes. It identifies tensions between liberty-based rationales and equality-based rationales, and surveys research findings on the outcomes of school choice policies, especially with regard to…

  4. The Stay/Switch Model of Concurrent Choice

    ERIC Educational Resources Information Center

    MacDonall, James S.

    2009-01-01

    This experiment compared descriptions of concurrent choice by the stay/switch model, which says choice is a function of the reinforcers obtained for staying at and for switching from each alternative, and the generalized matching law, which says choice is a function of the total reinforcers obtained at each alternative. For the stay/switch model…

  5. Free School Choice and the Educational Achievement Gap

    ERIC Educational Resources Information Center

    van Welie, Liesbeth; Hartog, Joop; Cornelisz, Ilja

    2013-01-01

    In the Netherlands, school choice is free and all schools are equally funded by the government. We measured distance from home to school as a proxy for the selectivity of choice and used characteristics of the nearest school to explain the choice of a school other than the nearest school. Almost 89% of all pupils in the 4 largest cities do not…

  6. A Case Study of Technology Choices by High School Students

    ERIC Educational Resources Information Center

    Owens-Hartman, Amy R.

    2015-01-01

    The purpose of this case study was to examine student technology choices when given the freedom to choose technology devices to complete a project-based learning activity in a content area of study. The study also analyzed factors affecting technology choice as well as how technology proficiency scores aligned to technology choices. Patterns and…

  7. School Choice: Today's Scope and Barriers to Growth

    ERIC Educational Resources Information Center

    Manno, Bruno V.

    2010-01-01

    Few people realize the movement's breadth and the forms in which school choice expansion is manifest. Out of slightly more than 57 million K-12 schoolchildren, almost 29.4 million--nearly 52%--are enrolled in a K-12 school choice option. This article provides an overview of the scope of school choice today and summarizes the political, policy, and…

  8. Who Gains, Who Loses from School Choice: A Research Summary.

    ERIC Educational Resources Information Center

    Fuller, Bruce

    Although the school-choice movement has spread quickly, little time has been taken to assess whether the claimed benefits of school choice have actually been realized. This policy brief summarizes empirical evidence to date and addresses the following questions: Who gains from school choice and who loses? Do innovative school organizations arise…

  9. The School Choice Market in China: A Case Study

    ERIC Educational Resources Information Center

    Wu, Xiaoxin

    2013-01-01

    Background: In contrast to the top-down government-designated school choice programmes in many countries, e.g. in the UK and USA in particular, school choice in the Chinese context is a bottom-up movement initiated by parents and is characterised by the payment of a substantial "choice fee" to the preferred school, and by competition by…

  10. Preliminary Assessment of Choice Making among Children with Rett Syndrome.

    ERIC Educational Resources Information Center

    Sigafoos, Jeff; And Others

    1995-01-01

    Choice making was studied among 7 students (ages 7-17) with Rett syndrome. Half the opportunities to choose food, beverage, and leisure items elapsed without a choice being made. Results suggest that the relationship between selecting and accepting items vary as a function of task configuration, and lack of choice may not necessarily indicate lack…

  11. Expanding Choice: Tax Credits and Educational Access in Idaho

    ERIC Educational Resources Information Center

    Carpenter, Dick M., II

    2011-01-01

    The past 30 years have seen a steady expansion in the educational choices available to parents as school choice programs have spread around the country. Enabling parents to choose schools that fit their children's unique needs is a win-win-win: Research shows that such school choice policies benefit the children who participate, give traditional…

  12. Female Adolescents' Educational Choices about Reproductive Health Modules

    ERIC Educational Resources Information Center

    Gold, Melanie A.; Chiappetta, Laurel; Young, Amanda J.; Zuckoff, Allan; DiClemente, Carlo C.

    2008-01-01

    Purpose: To assess girls' reproductive educational choices, satisfaction with choice, and relationship between demographics, module choice, and satisfaction. Methods: We recruited 286 girls, aged 13 to 21 years, from a hospital-based adolescent clinic, from advertisements, and by word of mouth. At enrollment, participants completed a 60-minute…

  13. Freedom and School Choice in American Education. Education Policy

    ERIC Educational Resources Information Center

    Forster, Greg, Ed.; Thompson, C. Bradley, Ed.

    2011-01-01

    Leading intellectual figures in the school reform movement, all of them favoring approaches centered around the value of competition and choice, outline different visions for the goal of choice-oriented educational reform and the best means for achieving it. This volume takes the reader inside the movement to empower parents with choice, airing…

  14. Choice Strategies in Multiple-Cue Probability Learning

    ERIC Educational Resources Information Center

    White, Chris M.; Koehler, Derek J.

    2007-01-01

    Choice strategies for selecting among outcomes in multiple-cue probability learning were investigated using a simulated medical diagnosis task. Expected choice probabilities (the proportion of times each outcome was selected given each cue pattern) under alternative choice strategies were constructed from corresponding observed judged…

  15. 48 CFR 352.233-70 - Choice of law (overseas).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Choice of law (overseas... Choice of law (overseas). As prescribed in 333.215-70(a), the Contracting Officer shall insert the following clause: Choice of Law (Overseas) (January 2010) This contract shall be construed in...

  16. 14 CFR 1260.59 - Choice of law.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Choice of law. 1260.59 Section 1260.59... Special Conditions § 1260.59 Choice of law. Choice of Law October 2000 The rights and obligations of the parties to the grant (or cooperative agreement) shall be ascertainable by recourse to the laws of...

  17. 14 CFR 1260.59 - Choice of law.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Choice of law. 1260.59 Section 1260.59... Special Conditions § 1260.59 Choice of law. Choice of Law October 2000 The rights and obligations of the parties to the grant (or cooperative agreement) shall be ascertainable by recourse to the laws of...

  18. 48 CFR 252.233-7001 - Choice of law (overseas).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Choice of law (overseas... of Provisions And Clauses 252.233-7001 Choice of law (overseas). As prescribed in 233.215-70, use the following clause: Choice of Law (Overseas) (JUN 1997) This contract shall be construed and interpreted...

  19. School Choice and Social Controversy: Politics, Policy, and Law.

    ERIC Educational Resources Information Center

    Sugarman, Stephen D., Ed.; Kemerer, Frank R., Ed.

    The essays in this collection provide analysis designed to be helpful to all sides of the school choice debate and to those charged with designing and implementing school choice programs. Discussion of the types, politics, and consequences of school choice is followed by discussion of the implications for school finance, accountability, and…

  20. Parent Choice of Early Childhood Education and Care Services

    ERIC Educational Resources Information Center

    Noble, Karen

    2007-01-01

    This paper reports on a study designed to enhance knowledge and understanding of parent choice in relation to early childhood education and care (ECEC) services. It investigates the ways parents make their choices of early childhood services and examines and interprets the meanings they ascribe to those choices. An orthodox grounded theory…

  1. Celebrating Children's Choices: 25 Years of Children's Favorite Books.

    ERIC Educational Resources Information Center

    Post, Arden DeVries

    This book provides the background and development of the Children's Choices project and highlights many of the best known and most popular books that have appeared on the Children's Choices list over the past 25 years. Each book selection features a picture of the book jacket, an annotation from the Choices list, a list of classroom applications,…

  2. Section II: Dealing with Conflict--The Element of Personal Choice: Personal Choice in the American Revolution

    ERIC Educational Resources Information Center

    Social Education, 1974

    1974-01-01

    An introductory and a negotiations exercise offer activities related to the choices offered to the participants in the American Revolution. The choices offered are discussed from the viewpoint of Roger Fisher, a law professor. (KM)

  3. Genetic Algorithms for Multiple-Choice Problems

    NASA Astrophysics Data System (ADS)

    Aickelin, Uwe

    2010-04-01

    This thesis investigates the use of problem-specific knowledge to enhance a genetic algorithm approach to multiple-choice optimisation problems.It shows that such information can significantly enhance performance, but that the choice of information and the way it is included are important factors for success.Two multiple-choice problems are considered.The first is constructing a feasible nurse roster that considers as many requests as possible.In the second problem, shops are allocated to locations in a mall subject to constraints and maximising the overall income.Genetic algorithms are chosen for their well-known robustness and ability to solve large and complex discrete optimisation problems.However, a survey of the literature reveals room for further research into generic ways to include constraints into a genetic algorithm framework.Hence, the main theme of this work is to balance feasibility and cost of solutions.In particular, co-operative co-evolution with hierarchical sub-populations, problem structure exploiting repair schemes and indirect genetic algorithms with self-adjusting decoder functions are identified as promising approaches.The research starts by applying standard genetic algorithms to the problems and explaining the failure of such approaches due to epistasis.To overcome this, problem-specific information is added in a variety of ways, some of which are designed to increase the number of feasible solutions found whilst others are intended to improve the quality of such solutions.As well as a theoretical discussion as to the underlying reasons for using each operator,extensive computational experiments are carried out on a variety of data.These show that the indirect approach relies less on problem structure and hence is easier to implement and superior in solution quality.

  4. Chance, choice, and the future of reproduction.

    PubMed

    Miller, W B

    1983-11-01

    The evolution of reproduction has been characterized by the development of complex biological and behavioral mechanisms that serve to regulate chance events. Human reproduction has been characterized by the increasing importance of individual choice. Some contemporary manifestations of this broad trend are the high incidence of contraceptive and "proceptive" behavior among couples in Western, industrialized nations. The former behavior willingly attempts to prevent conception while the latter actively attempts to induce conception (such as concentrating intercourse around the time of ovulation). Both patterns of behavior indicate that a choice is being made. A 3-year study of 1000 women revealed proceptive behavior as the most important factor predicting occurance of conception among married couples in the United States. The general strategeis people follow while making childbearing decisions: termination, sequencing, and pre-planning form a continuum following the historical trend toward greater reproductive control. In the terminating strategy, a couple makes no decision about child bearing until the number of children they have become enough or too much. In the sequencing strategy, decisions to have children are made 1 child at a time until a satisfactory limit is reached. In the pre-planning strategy, a plan is worked out ahead of time and is subsequently carried out. As new reproductive technology is introduced and as progressive change is made in society's reproductive related values and beliefs, choice will continue to dominate chance as the highly likely trend for the future of reproduction. Surrogate maternity is just 1 example of this trend. However, these new options, which culminate in the theory and practice of "progensis," (still in its infancy), as well as offering a rich opportunity, can also incur psychological burdens on a couple. Thus, as with any kind of freedom, these developments will require care, caution and responsibility.

  5. Preferred choice of work setting among nurses in Thailand: A discrete choice experiment.

    PubMed

    Kunaviktikul, Wipada; Chitpakdee, Bunpitcha; Srisuphan, Wichit; Bossert, Thomas

    2014-05-08

    The shortage of health personnel and nurses is an important issue in many developed and developing countries. Understanding preferred choice of work setting is an important strategy for retaining nurses in their work. The purpose of this study was to determine choices made by nurses in Thailand relative to their preferences for a work setting. A discrete choice experiment was conducted to elicit attributes and levels of job characteristics expected to contribute to work-place preferences. The sample included 921 nurses and was selected using stratified random sampling. A random effects probit model was used to identify factors contributing to work-setting preferences. The results showed that nurses' first work-place preference was a high level of work setting. The second preference was to work in a hospital in the same province as their families. The results provide information for hospital and nurse administrators and policymakers seeking to address the nursing shortage.

  6. Transgender Reproductive Choice and Fertility Preservation.

    PubMed

    Mitu, Khadija

    2016-11-01

    Increasing numbers of young transgender people are now using medical technologies to achieve a physical gender transition. However, the procedures of physical gender transition might cause temporary or permanent sterility. Thus many transgender people are now using fertility preservation technologies. Nonetheless, they can experience dilemmas in making reproductive and family-building decisions and face challenges in gaining access to and utilizing fertility preservation services. Based on qualitative research conducted with transgender men and women who used reproductive technologies for preserving their fertility before or during their physical transition, this paper contributes to the discourse of reproductive choice by the inclusion of transgender people's experience.

  7. Governing genetics: reifying choice and progress.

    PubMed

    Kerr, Anne

    2003-08-01

    The governance of genetics involves a wide range of policy networks and covers a considerable array of genetic technoscience. Despite this apparent diversity, the uniformity of some genetic governance requires investigation. Reviewing policy documents on genetic patenting and embryonic stem cell research, I shall argue that policy networks often conceive of the ethical aspects of these practices in similar ways. In particular, I shall argue that individual choice and medico-scientific progress are common rhetorical devices in their frameworks. I shall end by commenting upon the implications of these trends for the future.

  8. Current Challenges in Bayesian Model Choice

    NASA Astrophysics Data System (ADS)

    Clyde, M. A.; Berger, J. O.; Bullard, F.; Ford, E. B.; Jefferys, W. H.; Luo, R.; Paulo, R.; Loredo, T.

    2007-11-01

    Model selection (and the related issue of model uncertainty) arises in many astronomical problems, and, in particular, has been one of the focal areas of the Exoplanet working group under the SAMSI (Statistics and Applied Mathematical Sciences Institute) Astrostatistcs Exoplanet program. We provide an overview of the Bayesian approach to model selection and highlight the challenges involved in implementing Bayesian model choice in four stylized problems. We review some of the current methods used by statisticians and astronomers and present recent developments in the area. We discuss the applicability, computational challenges, and performance of suggested methods and conclude with recommendations and open questions.

  9. Super-resolution optical microscopy: multiple choices.

    PubMed

    Huang, Bo

    2010-02-01

    The recent invention of super-resolution optical microscopy enables the visualization of fine features in biological samples with unprecedented clarity. It creates numerous opportunities in biology because vast amount of previously obscured subcellular processes now can be directly observed. Rapid development in this field in the past two years offers many imaging modalities that address different needs but they also complicates the choice of the 'perfect' method for answering a specific question. Here I will briefly describe the principles of super-resolution optical microscopy techniques and then focus on comparing their characteristics in various aspects of practical applications.

  10. Women's choices for fetal chromosome analysis.

    PubMed

    Abramsky, L; Rodeck, C H

    1991-01-01

    Five hundred and eighty women aged 35 or more at the expected date of delivery were offered the chance to join the MRC trial comparing CVS and amniocentesis at Queen Charlotte's Hospital. After a 1 h non-directive counselling session, they were asked to choose between having no test, having amniocentesis, or joining the trial in the hopes of having CVS (or in some cases having CVS outside the trial). The majority of women chose to have some test, and CVS was a more popular choice than amniocentesis.

  11. Ambient taxes when polluters have multiple choices

    SciTech Connect

    Horan, R.D.; Shortle, J.S.; Abler, D.G.

    1998-09-01

    Economic research on environmental policy design has largely been concerned with the merits of emissions-based economic incentives (e.g., emissions charges, emissions reduction subsidies, transferable discharge permits). Ambient-based tax-subsidy schemes have drawn considerable interest in nonpoint pollution literature as alternatives to emissions-based instruments. Expanding especially on Segerson`s seminal article, this article examines the optimal design and budget-balancing properties of ambient tax-subsidy schemes under more realistic assumptions about the dimensions of firms` choice sets than prior research.

  12. MEDICAL EXPENDITURE RISK AND HOUSEHOLD PORTFOLIO CHOICE

    PubMed Central

    Goldman, Dana

    2013-01-01

    Medical expenses are an increasingly important contributor to household financial risk. We examine the effect of medical expenditure risk on the willingness of Medicare beneficiaries to hold risky assets. Using a discrete factor maximum likelihood method to address the endogeneity of insurance choices, we find that having a moderately protective Medigap or employer supplemental policy increases risky asset holding by 7.1 percentage points relative to those without supplemental coverage, while participation in a highly protective Medicare HMO increases risky asset holding by 13.0 percentage points. Our results highlight an important link between the availability of health insurance and financial behavior. PMID:23997424

  13. Modeling choice and valuation in decision experiments.

    PubMed

    Loomes, Graham

    2010-07-01

    This article develops a parsimonious descriptive model of individual choice and valuation in the kinds of experiments that constitute a substantial part of the literature relating to decision making under risk and uncertainty. It suggests that many of the best known "regularities" observed in those experiments may arise from a tendency for participants to perceive probabilities and payoffs in a particular way. This model organizes more of the data than any other extant model and generates a number of novel testable implications which are examined with new data.

  14. The 'empty choice': A sociological examination of choosing medical research participation in resource-limited Sub-Saharan Africa.

    PubMed

    Kingori, Patricia

    2015-09-01

    This article explores the views of frontline research staff in different Sub-Saharan African contexts on the notion of choice in biomedical research. It argues that the current emphasis on individual choice, in the conduct of biomedical research, ignores significant structural and contextual factors in resource-limited settings. These factors severely constrain individual options and often make biomedical research enrolment the most amenable route to healthcare for the world's poorest. From the position of frontline research staff, local contextual factors and structural issues narrowly frame the parameters within which many prospective participants are asked to choose, to such an extent that individuals are effectively presented with an 'empty choice'. The article draws on ethnographic and interview data and insights gained through graphic elucidation techniques. It demonstrates that for frontline research staff, macro-level structural factors and their bearing on everyday realities shape what choice in biomedical research participation means in practice.

  15. Education by the Numbers: The Fiscal Effect of School Choice Programs, 1990-2006. School Choice Issues in Depth

    ERIC Educational Resources Information Center

    Aud, Susan L.

    2007-01-01

    School choice programs, which allow students to attend the public or private school of their choice using public funds, have taken root in the U.S. and are growing rapidly both in number and size. Their fiscal impact has become an important political issue. Proponents say school choice saves money because private schooling is more efficient,…

  16. The ABCs of School Choice: The Comprehensive Guide to Every Private School Choice Program in America. 2013 Edition

    ERIC Educational Resources Information Center

    Friedman Foundation for Educational Choice, 2013

    2013-01-01

    "The ABCs of School Choice" is the most comprehensive guide to every private school choice program in America, showcasing the voucher, tax-credit scholarship, education savings accounts, and individual tax credit/deduction programs currently operating in 21 states and Washington, D.C. "The ABCs of School Choice" provides policymakers, advocates,…

  17. Simulating future value in intertemporal choice

    PubMed Central

    Solway, Alec; Lohrenz, Terry; Montague, P. Read

    2017-01-01

    The laboratory study of how humans and other animals trade-off value and time has a long and storied history, and is the subject of a vast literature. However, despite a long history of study, there is no agreed upon mechanistic explanation of how intertemporal choice preferences arise. Several theorists have recently proposed model-based reinforcement learning as a candidate framework. This framework describes a suite of algorithms by which a model of the environment, in the form of a state transition function and reward function, can be converted on-line into a decision. The state transition function allows the model-based system to make decisions based on projected future states, while the reward function assigns value to each state, together capturing the necessary components for successful intertemporal choice. Empirical work has also pointed to a possible relationship between increased prospection and reduced discounting. In the current paper, we look for direct evidence of a relationship between temporal discounting and model-based control in a large new data set (n = 168). However, testing the relationship under several different modeling formulations revealed no indication that the two quantities are related. PMID:28225034

  18. Insights into decision making using choice probability.

    PubMed

    Crapse, Trinity B; Basso, Michele A

    2015-12-01

    A long-standing question in systems neuroscience is how the activity of single neurons gives rise to our perceptions and actions. Critical insights into this question occurred in the last part of the 20th century when scientists began linking modulations of neuronal activity directly to perceptual behavior. A significant conceptual advance was the application of signal detection theory to both neuronal activity and behavior, providing a quantitative assessment of the relationship between brain and behavior. One metric that emerged from these efforts was choice probability (CP), which provides information about how well an ideal observer can predict the choice an animal makes from a neuron's discharge rate distribution. In this review, we describe where CP has been studied, locational trends in the values found, and why CP values are typically so low. We discuss its dependence on correlated activity among neurons of a population, assess whether it arises from feedforward or feedback mechanisms, and investigate what CP tells us about how many neurons are required for a decision and how they are pooled to do so.

  19. The role of simulation in intertemporal choices

    PubMed Central

    O'Connell, Garret; Christakou, Anastasia; Chakrabarti, Bhismadev

    2015-01-01

    One route to understanding the thoughts and feelings of others is by mentally putting one's self in their shoes and seeing the world from their perspective, i.e., by simulation. Simulation is potentially used not only for inferring how others feel, but also for predicting how we ourselves will feel in the future. For instance, one might judge the worth of a future reward by simulating how much it will eventually be enjoyed. In intertemporal choices between smaller immediate and larger delayed rewards, it is observed that as the length of delay increases, delayed rewards lose subjective value; a phenomenon known as temporal discounting. In this article, we develop a theoretical framework for the proposition that simulation mechanisms involved in empathizing with others also underlie intertemporal choices. This framework yields a testable psychological account of temporal discounting based on simulation. Such an account, if experimentally validated, could have important implications for how simulation mechanisms are investigated, and makes predictions about special populations characterized by putative deficits in simulating others. PMID:25873852

  20. Modulation of Drosophila male behavioral choice

    PubMed Central

    Certel, Sarah J.; Savella, Mary Grace; Schlegel, Dana C. F.; Kravitz, Edward A.

    2007-01-01

    The reproductive and defensive behaviors that are initiated in response to specific sensory cues can provide insight into how choices are made between different social behaviors. We manipulated both the activity and sex of a subset of neurons and found significant changes in male social behavior. Results from aggression assays indicate that the neuromodulator octopamine (OCT) is necessary for Drosophila males to coordinate sensory cue information presented by a second male and respond with the appropriate behavior: aggression rather than courtship. In competitive male courtship assays, males with no OCT or with low OCT levels do not adapt to changing sensory cues and court both males and females. We identified a small subset of neurons in the suboesophageal ganglion region of the adult male brain that coexpress OCT and male forms of the neural sex determination factor, Fruitless (FruM). A single FruM-positive OCT neuron sends extensive bilateral arborizations to the suboesophageal ganglion, the lateral accessory lobe, and possibly the posterior antennal lobe, suggesting a mechanism for integrating multiple sensory modalities. Furthermore, eliminating the expression of FruM by transformer expression in OCT/tyramine neurons changes the aggression versus courtship response behavior. These results provide insight into how complex social behaviors are coordinated in the nervous system and suggest a role for neuromodulators in the functioning of male-specific circuitry relating to behavioral choice. PMID:17360588

  1. Hedonism and the choice of everyday activities

    PubMed Central

    Taquet, Maxime; Quoidbach, Jordi; de Montjoye, Yves-Alexandre; Desseilles, Martin; Gross, James J.

    2016-01-01

    Most theories of motivation have highlighted that human behavior is guided by the hedonic principle, according to which our choices of daily activities aim to minimize negative affect and maximize positive affect. However, it is not clear how to reconcile this idea with the fact that people routinely engage in unpleasant yet necessary activities. To address this issue, we monitored in real time the activities and moods of over 28,000 people across an average of 27 d using a multiplatform smartphone application. We found that people’s choices of activities followed a hedonic flexibility principle. Specifically, people were more likely to engage in mood-increasing activities (e.g., play sports) when they felt bad, and to engage in useful but mood-decreasing activities (e.g., housework) when they felt good. These findings clarify how hedonic considerations shape human behavior. They may explain how humans overcome the allure of short-term gains in happiness to maximize long-term welfare. PMID:27528666

  2. Free Choice and Patient Best Interests.

    PubMed

    Bullock, Emma C

    2016-12-01

    In medical practice, the doctrine of informed consent is generally understood to have priority over the medical practitioner's duty of care to her patient. A common consequentialist argument for the prioritisation of informed consent above the duty of care involves the claim that respect for a patient's free choice is the best way of protecting that patient's best interests; since the patient has a special expertise over her values and preferences regarding non-medical goods she is ideally placed to make a decision that will protect her interests. In this paper I argue against two consequentialist justifications for a blanket prioritisation of informed consent over the duty of care by considering cases in which patients have imperfect access to their overall best interests. Furthermore, I argue that there are cases where the mere presentation of choice under the doctrine of informed consent is detrimental to patient best interests. I end the paper by considering more nuanced approaches to resolving the conflict between informed consent and the duty of care and consider the option of permitting patients to waive informed consent.

  3. Choice mechanisms for past, temporally extended outcomes

    PubMed Central

    Vestergaard, Martin D.; Schultz, Wolfram

    2015-01-01

    Accurate retrospection is critical in many decision scenarios ranging from investment banking to hedonic psychology. A notoriously difficult case is to integrate previously perceived values over the duration of an experience. Failure in retrospective evaluation leads to suboptimal outcome when previous experiences are under consideration for revisit. A biologically plausible mechanism underlying evaluation of temporally extended outcomes is leaky integration of evidence. The leaky integrator favours positive temporal contrasts, in turn leading to undue emphasis on recency. To investigate choice mechanisms underlying suboptimal outcome based on retrospective evaluation, we used computational and behavioural techniques to model choice between perceived extended outcomes with different temporal profiles. Second-price auctions served to establish the perceived values of virtual coins offered sequentially to humans in a rapid monetary gambling task. Results show that lesser-valued options involving successive growth were systematically preferred to better options with declining temporal profiles. The disadvantageous inclination towards persistent growth was mitigated in some individuals in whom a longer time constant of the leaky integrator resulted in fewer violations of dominance. These results demonstrate how focusing on immediate gains is less beneficial than considering longer perspectives. PMID:26063841

  4. Inversion of Electromagnetic Models for Bare Soil Parameter Estimation from Multifrequency Polarimetric SAR Data

    PubMed Central

    Pierdicca, Nazzareno; Castracane, Paolo; Pulvirenti, Luca

    2008-01-01

    The potentiality of polarimetric SAR data for the estimation of bare soil geophysical parameters (i.e., roughness and soil moisture) is investigated in this work. For this purpose, two forward models available in the literature, able to simulate the measurements of a multifrequency radar polarimeter, have been implemented for use within an inversion scheme. A multiplicative noise has been considered in the multidimensional space of the elements of the polarimetric Covariance Matrix, by adopting a complex Wishart distribution to account for speckle effects. An additive error has been also introduced on the simulated measurements to account for calibration and model errors. Maximum a Posteriori Probability and Minimum Variance criteria have been considered to perform the inversion. As for the algorithms to implement the criteria, simple optimization/integration procedures have been used. A Neural Network approach has been adopted as well. A correlation between the roughness parameters has been also supposed in the simulation as a priori information, to evaluate its effect on the estimation accuracy. The methods have been tested on simulated data to compare their performances as function of number of looks, incidence angles and frequency bands, thus identifying the best radar configuration in terms of estimation accuracy. Polarimetric measurements acquired during MAC Europe and SIR-C campaigns, over selected bare soil fields, have been also used as validation data. PMID:27873982

  5. A computer program for enzyme kinetics that combines model discrimination, parameter refinement and sequential experimental design.

    PubMed Central

    Franco, R; Gavaldà, M T; Canela, E I

    1986-01-01

    A method of model discrimination and parameter estimation in enzyme kinetics is proposed. The experimental design and analysis of the model are carried out simultaneously and the stopping rule for experimentation is deduced by the experimenter when the probabilities a posteriori indicate that one model is clearly superior to the rest. A FORTRAN77 program specifically developed for joint designs is given. The method is very powerful, as indicated by its usefulness in the discrimination between models. For example, it has been successfully applied to three cases of enzyme kinetics (a single-substrate Michaelian reaction with product inhibition, a single-substrate complex reaction and a two-substrate reaction). By using this method the most probable model and the estimates of the parameters can be obtained in one experimental session. The FORTRAN77 program is deposited as Supplementary Publication SUP 50134 (19 pages) at the British Library (Lending Division), Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1986) 233, 5. PMID:3800965

  6. Item analysis of in use multiple choice questions in pharmacology

    PubMed Central

    Kaur, Mandeep; Singla, Shweta; Mahajan, Rajiv

    2016-01-01

    Background: Multiple choice questions (MCQs) are a common method of assessment of medical students. The quality of MCQs is determined by three parameters such as difficulty index (DIF I), discrimination index (DI), and distracter efficiency (DE). Objectives: The objective of this study is to assess the quality of MCQs currently in use in pharmacology and discard the MCQs which are not found useful. Materials and Methods: A class test of central nervous system unit was conducted in the Department of Pharmacology. This test comprised 50 MCQs/items and 150 distracters. A correct response to an item was awarded one mark with no negative marking for incorrect response. Each item was analyzed for three parameters such as DIF I, DI, and DE. Results: DIF of 38 (76%) items was in the acceptable range (P = 30–70%), 11 (22%) items were too easy (P > 70%), and 1 (2%) item was too difficult (P < 30%). DI of 31 (62%) items was excellent (d > 0.35), of 12 (24%) items was good (d = 0.20–0.34), and of 7 (14%) items was poor (d < 0.20). A total of 50 items had 150 distracters. Among these, 27 (18%) were nonfunctional distracters (NFDs) and 123 (82%) were functional distracters. Items with one NFD were 11 and with two NFDs were 8. Based on these parameters, 6 items were discarded, 17 were revised, and 27 were kept for subsequent use. Conclusion: Item analysis is a valuable tool as it helps us to retain the valuable MCQs and discard the items which are not useful. It also helps in increasing our skills in test construction and identifies the specific areas of course content which need greater emphasis or clarity. PMID:27563581

  7. No Effects of Psychosocial Stress on Intertemporal Choice

    PubMed Central

    Seinstra, Maayke; Fehr, Ernst; Joëls, Marian; Kalenscher, Tobias

    2013-01-01

    Intertemporal choices - involving decisions which trade off instant and delayed outcomes - are often made under stress. It remains unknown, however, whether and how stress affects intertemporal choice. We subjected 142 healthy male subjects to a laboratory stress or control protocol, and asked them to make a series of intertemporal choices either directly after stress, or 20 minutes later (resulting in four experimental groups). Based on theory and evidence from behavioral economics and cellular neuroscience, we predicted a bidirectional effect of stress on intertemporal choice, with increases in impatience or present bias immediately after stress, but decreases in present bias or impatience when subjects are tested 20 minutes later. However, our results show no effects of stress on intertemporal choice at either time point, and individual differences in stress reactivity (changes in stress hormone levels over time) are not related to individual differences in intertemporal choice. Together, we did not find support for the hypothesis that psychosocial laboratory stressors affect intertemporal choice. PMID:24250800

  8. Free availability of high-energy foods led to energy over-ingestion and protein under-ingestion in choice-fed broilers.

    PubMed

    Catanese, Francisco; Rodriguez Ganduglia, Héctor; Villalba, Juan J; Distel, Roberto A

    2015-12-01

    The objective of this study was to compare energy and protein content of the diet selected by choice-fed broilers with that of broilers fed a balanced diet. One hundred and eighty 1-day-old male broilers were randomly assigned in groups of 10 to one of three experimental treatments (n = 6). Control broilers were fed a standard balanced diet, whereas choice-fed broilers were fed three foods which were more concentrated (Choice C+ treatment) or less concentrated (Choice C- treatment) in protein, carbohydrate or fat. We evaluated food intake behavior, nutrient intake, and performance parameters of broilers from 2 to 7 weeks of age. Choice C+ broilers showed enhanced preference for the high-fat food, which led to higher energy intake and lower protein intake than those of control broilers at 2 to 4 weeks of age. Body weight, weight gain and feed conversion efficiency were negatively affected by diet selection of Choice C+ broilers. Choice C- broilers selected a balanced diet, and showed performance parameters similar to those of control broilers. Our results supported the hypothesis that free availability of high-energy foods bias ingestive behavior of choice-fed broilers toward selecting a diet with higher energy and lower protein than needed for normal growth.

  9. Technology choice in a least-cost expansion analysis framework: Implications for state regulators

    SciTech Connect

    Guziel, K.A.; South, D.W.

    1990-01-01

    It is inevitable that new power plants will need to be constructed in the near future; however, it is unclear which technologies will be selected for these new plants. In a study for the US Department of Energy, the impacts of fuel prices, length of the planning period, and the characteristics of the generating system were examined for their influence on technology choice in 10 representative power pools. It was determined that natural gas combined-cycle technology was generally preferred for base-load and intermediate/cycling capacity when gas prices are low and the planning period is short (10 years). Integrated coal gasification combined-cycle plants were selected to serve most base-load requirements under other conditions. One aspect often overlooked in making a least-cost technology choice is system reliability: nonoptimal technology choices call be made if alternative expansion plans do not have the same level of reliability when discounted system costs are compared. Utilities have become capital averse due to a multitude of regulatory, market, and supply issues. Utilities are looking at natural gas technologies, since they offer rapid construction/deployment, low capital investment, and higher availability than coal-fired technologies. Of concern to state regulators is how to evaluate a least-cost plan. Key parameters studied were based on the following: (1) What is the impact of alternative gas projections on technology choice (2) What influence does the planning horizon (10 versus 30 years) have on technology choice (3) How important are existing system characteristics (e.g., mix of technologies, operating costs, load shape) on technology choice This paper summarizes the analysis framework and presents results for two power pools: Power Pool 1, the American Electric Power (AEP) service territory, and Power Pool 16, with all the utilities in Florida. 7 refs., 17 figs., 2 tabs. (JF)

  10. The Effects of a Free School Choice Policy on Parents' School Choice Behaviour

    ERIC Educational Resources Information Center

    Altrichter, Herbert; Bacher, Johann; Beham, Martina; Nagy, Gertrud; Wetzelhutter, Daniela

    2011-01-01

    Recently, European school systems have seen various attempts to "modernise" their governance. Market and competition oriented reforms have not been central to governance innovation strategies in German speaking countries, however, their number and relevance is rising in recent years. A free school choice policy which abolishes…

  11. Spoilt for Choice, Spoilt by Choice: Long-Term Consequences of Limitations Imposed by Social Background

    ERIC Educational Resources Information Center

    Duckworth, Vicky; Cochrane, Matthew

    2012-01-01

    Purpose: The purpose of this paper is to explore the choices learners have in steering their way through the educational system in the UK. Design/methodology/approach: The paper draws on data from two studies, one conducted in a state secondary school and the other in a Further Education College, both based in the north-west of England. Both used…

  12. Latino Parents' Choice of Magnet School: How School Choice Differs across Racial and Ethnic Boundaries

    ERIC Educational Resources Information Center

    Haynes, Katherine Taylor; Phillips, Kristie J. R.; Goldring, Ellen B.

    2010-01-01

    Historically, magnet schools have served predominantly Black and Anglo populations. Consequently, little research exists on Latino parent's engagement in school choice and their patterns of participation. Magnet schools are increasingly part of the landscape for improving school achievement for all students. Yet Latino enrollment rates in magnet…

  13. Free Choice or Adaptable Choice: Self-Determination Theory and Play

    ERIC Educational Resources Information Center

    King, Pete; Howard, Justine

    2016-01-01

    The authors explore the use of three basic tenets from Self-Determination Theory--competence, relatedness, and autonomy--for a definition of play that resists the current popular call for play to be freely chosen. They explore whether free play truly exists and whether complete choice constitutes an absolute requirement for children to consider…

  14. The Composition of Consideration and Choice Sets in Undergraduate University Choice: An Exploratory Study

    ERIC Educational Resources Information Center

    Dawes, Philip L.; Brown, Jennifer

    2004-01-01

    We examine university choice as a case of consumer decision making and adopt a brand elimination framework. This approach is predicated on the grounds that a large amount of research in consumer behavior has shown that in markets where there are many alternative brands, consumers use phased-decision strategies. In these research studies, the…

  15. Choice of College Major: An Exploration of Appalachian Female Choice of an Early Childhood Education Major

    ERIC Educational Resources Information Center

    Gannoe, Lisa N.

    2013-01-01

    First generation Appalachian female students are exposed to gender differences in roles and career choices that are modeled in the family. A case study approach was used to obtain qualitative data from five students at Eastern Kentucky University and their mothers regarding why these students chose to major in child development and early childhood…

  16. Choice, Contol and Change: Using Scientific Evidence to Promote Healthful Food and Activity Choices

    ERIC Educational Resources Information Center

    Koch, Pamela; Barton, Angela Calabrese; Whitaker, Rabi; Contento, Isobel

    2007-01-01

    Childhood obesity and its long-term health implications should be of major concern to science educators. In an effort to support teachers and youth about this growing problem, a five-unit, 19-lesson module entitled Choice, Control, and Change (C3) was developed at Teachers College Columbia University. C3 is a standards-driven and inquiry-based…

  17. Word-Tool Match. Review Software for Basic CHOICE. CHOICE (Challenging Options in Career Education).

    ERIC Educational Resources Information Center

    Pitts, Ilse M.; And Others

    CHOICE Word-Tool Match provides migrant youth the opportunity to use the computer in self-directed ways, while reinforcing job and role information presented in Basic Job and Role activity folders and workbooks. Learners select whether to play with one or two players, the career that will provide the theme for the game, and whether to play the…

  18. Choice in a Variable Environment: Visit Patterns in the Dynamics of Choice

    ERIC Educational Resources Information Center

    Baum, William M.; Davison, Michael

    2004-01-01

    Molar and molecular views of behavior imply different approaches to data analysis. The molecular view privileges moment-to-moment analyses, whereas the molar view supports analysis of more and less extended activities. In concurrent performance, the molar view supports study of both extended patterns of choice and more local patterns of visiting…

  19. Parameter Plane Design Method

    DTIC Science & Technology

    1989-03-01

    Th usr a toente aninteer a thca sms b esta 1 Fp-ocsing 2. Enter P1 values, lwgt, ldig - > 9 Table I give us proper values. Table 1. PARAMETER TABLE...necessary and identify by block number) In this thesis a control systems analysis package is developed using parameter plane methods. It is an interactive...designer is able to choose values of the parameters which provide a good compromise between cost and dynamic behavior. 20 Distribution Availability of

  20. HYDROGEN ATOM THERMAL PARAMETERS.

    PubMed

    JENSEN, L H; SUNDARALINGAM, M

    1964-09-11

    Isotropic hydrogen atom thermal parameters for N,N'- hexamethylenebispropionamide have been determined. They show a definite trend and vary from approximately the same as the mean thermal parameters for atoms other than hydrogen near the center of the molecule to appreciably greater for atoms near the end. The indicated trend for this compound, along with other results, provides the basis for a possible explanation of the anomolous values that have been obtained for hydrogen atom thermal parameters.